Adhesive compositions and uses thereof

Abstract

Methods of producing a thermoplastic dispersion or adhesive from unprocessed plastic and / or waste plastic are described, as well as uses of the dispersion or adhesive for producing thermoplastic composite products, such as composite boards. A portion of the thermoplastic can be treated with heat and / or a catalyst, or reacted with a coupling agent to produce a functionalized thermoplastic, and / or dispersed in water under agitation to produce a thermoplastic dispersion.

Description

Technical Field

[0001] This invention relates to a method for producing thermoplastic dispersions and / or adhesives, and thus their use in the manufacture of plastic composite products. Background Technology

[0002] Plastic is a widely used material in both household and industrial products. Many countries are working to dispose of or use waste plastics in an economical and safe manner. Recycling plastics into other goods is known, but it requires energy and resources to wash the plastics, reduce them from their original shape to the desired particle size, and then reuse them in recycled products.

[0003] Adhesives (also known as adhesives) are used in a variety of industrial and consumer applications. One such adhesive is urea-formaldehyde (UF), named for its common synthetic route and overall structure. UF products are thermosetting resins or polymers used as adhesives / glues. However, UF adhesives have drawbacks such as volatile organic compound emissions, which can lead to harmful health effects, energy-intensive production processes, and associated regulatory hurdles. Therefore, alternative adhesives are needed. Furthermore, UF adhesives undergo a condensation reaction to bond materials, and this condensation reaction is reversible, especially under certain environmental conditions. In wet or humid areas, UF bonds can hydrolyze, meaning the bonds can break down and revert to their original components. This hydrolysis leads to reduced bond strength and durability, making UF adhesives less suitable for use in environments that expose them to moisture and potentially causing failure of the structural integrity of the bonded products.

[0004] Plastic waste presents a range of environmental, economic, and social challenges. These include environmental impacts caused by its non-biodegradability, such as marine pollution harming marine life, chemical leaching of hazardous products and byproducts into the food chain, microplastic pollution, and air pollution when plastics are burned for energy. Therefore, it is necessary to reduce, reuse, and recycle plastic waste to extend its usable lifespan and reduce its harmful environmental impacts.

[0005] The object of the present invention is to provide a method for manufacturing thermoplastic dispersions and / or adhesives, and optionally their uses, or at least to provide the public with an option available to them. Summary of the Invention

[0006] In a first aspect, we describe a method for producing thermoplastic dispersions, comprising introducing a polymer into an extruder, wherein the polymer is subjected to a treatment step.

[0007] In another aspect, we describe a particulate thermoplastic having an average particle size of less than 0.5 mm and a metal catalyst.

[0008] In another aspect, we describe a method for producing thermoplastic dispersions, which includes... Heating thermoplastics to produce molten thermoplastics. The thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles, and This involves processing the thermoplastic material.

[0009] In another aspect, we describe a thermoplastic dispersion comprising particulate thermoplastics having an average particle size of less than 0.5 mm, the particulate thermoplastics having i) Melt flow index greater than 8 g / 10 min at 190°C ii) Complex viscosity less than 5,000 Pa·s at 160°C iii) The average molecular weight is reduced by more than 30% relative to the source, untreated, or unprocessed thermoplastic, or any one or more of (iv)(i) to (iii).

[0010] In another aspect, we describe a method for producing thermoplastic dispersions, which includes... Heating thermoplastics to produce molten thermoplastics. The thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles, and The process involves subjecting the thermoplastic to treatment steps, which are selected from... i) Heating thermoplastics at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both.

[0011] In another aspect, we describe a method for producing thermoplastic dispersions, which includes... Heating thermoplastics to produce molten thermoplastics. Molten thermoplastic is dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles. The process involves subjecting the thermoplastic to treatment steps, which are selected from... i) Heating thermoplastics at the activation temperature, ii) Add a metal catalyst selected from metal oxides, metal acetates, metals having a single s orbital electron in the outer shell, or iii)(i) and (ii) both.

[0012] In another aspect, we describe a method for producing thermoplastic dispersions, which includes... Heating thermoplastics to produce molten thermoplastics. Molten thermoplastic is dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles. The process involves subjecting the thermoplastic to treatment steps, which are selected from... i) Heating thermoplastics at the activation temperature, ii) Adding a metal catalyst in the form of a metal acetate, a group XI metal oxide, or a metal sulfate, or iii)(i) and (ii) both.

[0013] In another aspect, we describe a method for producing thermoplastic dispersions, which includes... Heating thermoplastics to produce molten thermoplastics. Molten thermoplastic is dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles. The process involves subjecting molten thermoplastic (whether molten or dispersed) to a treatment step, the treatment step being selected from... i) Heating thermoplastics at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both, and Metal catalysts a) Increase the melt flow index of thermoplastics. b) Reduce the viscosity of thermoplastics. c) Reduce the molecular weight of thermoplastics, or d)(a) to (c) any one or more of them.

[0014] According to another aspect, a method for preparing a moisture-resistant composite material product is described, which includes... Obtain a thermoplastic dispersion, which is produced by the following manner. • Heating thermoplastics to produce molten thermoplastics, • The thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles, and • This includes the process of subjecting thermoplastics to treatment; Thermoplastic dispersions are combined with crosslinking agents and fibers to produce composite material mixtures, and Heat and pressure were applied to the composite mixture to form a moisture-resistant composite product, which exhibited less than about 15% swelling after 24 hours when measured by a 24-hour swelling test.

[0015] According to another aspect, a method for preparing a moisture-resistant composite material product is described, which includes... Obtain a thermoplastic dispersion, which is produced by the following manner. • Heating thermoplastics to produce molten thermoplastics, • The thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles, and • This includes the process of subjecting thermoplastics to treatment; Thermoplastic dispersions are combined with crosslinking agents and fibers to produce composite material mixtures, and Applying heat and pressure to composite material mixtures, and The moisture-resistant composite products do not include moisture-resistant mixtures other than thermoplastic dispersions.

[0016] According to another aspect, a method for preparing a moisture-resistant composite material product is described, which includes... Obtain a thermoplastic dispersion, which is produced by the following manner. • Heating thermoplastics to produce molten thermoplastics, • The thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles, and • In which thermoplastics are subjected to processing steps selected from the following i) Heating thermoplastics at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both; A thermoplastic dispersion is combined with a crosslinking agent and fibers, at a weight of approximately 1% to approximately 5% (based on the weight of the sheet), to produce a composite material mixture. Heat and pressure were applied to the composite mixture to form a moisture-resistant composite product, which exhibited less than about 15% swelling after 24 hours when measured by a 24-hour swelling test.

[0017] According to another aspect, a method for preparing a moisture-resistant composite material product is described, which includes... To obtain a thermoplastic dispersion comprising particulate thermoplastics with an average particle size of less than 0.5 mm and a crosslinking agent. Thermoplastic dispersions are mixed with fibers to form composite material mixtures, and Heat and pressure are applied to the composite mixture to form a thermoplastic composite product, which exhibits less than about 15% swelling after 24 hours when measured by a 24-hour swelling test.

[0018] According to another aspect, a method for producing thermoplastic composite products is described, comprising: A thermoplastic dispersion comprising particulate thermoplastics with an average particle size of less than 0.5 mm, a crosslinking agent, and a metal catalyst is obtained. Thermoplastic dispersions are mixed with fibers to form composite material mixtures, and Heat and pressure are applied to a composite material mixture in a press or mold to form a thermoplastic composite product.

[0019] According to another aspect, a method for producing thermoplastic composite products is described, comprising: A thermoplastic dispersion comprising particulate thermoplastics with an average particle size of less than 0.5 mm and a metal catalyst is obtained. Thermoplastic dispersions are mixed with crosslinking agents and fibers to form composite material mixtures, and Heat and pressure are applied to a composite material mixture in a press or mold to form a thermoplastic composite product.

[0020] According to another aspect, a method for producing thermoplastic composite products is described, comprising: Obtain an adhesive comprising particulate thermoplastics with an average particle size of less than 0.5 mm, a crosslinking agent, and a metal catalyst. The adhesive has been formed through the following process Thermoplastic material is introduced into the inlet end of one or more extruders, where it is melted and treated with a metal catalyst. The treated thermoplastic material is then combined with a crosslinking agent. Thermoplastic dispersions are mixed with fibers to form composite material mixtures, and Heat and pressure are applied to a composite material mixture in a press or mold to form a thermoplastic composite product.

[0021] According to another aspect, a method for producing thermoplastic composite products is described, comprising: To obtain a treated thermoplastic comprising particulate thermoplastic with an average particle size of less than 0.5 mm and a metal catalyst, The processed thermoplastic has been formed through the following process. Thermoplastic material is introduced into the inlet end of one or more extruders, and within the one or more extruders, the thermoplastic material is heated to produce molten thermoplastic material and treated with a metal catalyst to provide treated thermoplastic material. Treated thermoplastics are mixed with crosslinking agents and fibers to form composite material mixtures, and Heat and pressure are applied to a composite material mixture in a press or mold to form a thermoplastic composite product.

[0022] According to another aspect, a composite panel is described, comprising: Waste thermoplastics; Lignocellulose materials; and Metal catalysts Lignocellulose materials account for at least 75% of the composite board.

[0023] The following can apply to any one or more of the aspects described above.

[0024] In one instance, the processing steps are selected from... i) Heating thermoplastics at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both.

[0025] The heat and pressure applied to the composite mixture can be provided in a press or mold.

[0026] The thermoplastic used to form the adhesive can be in the form of a powder or a dispersion. In one example, the thermoplastic used to form the adhesive is an aqueous thermoplastic dispersion.

[0027] In one example, the activation temperature mentioned in aspects of the invention is at least 150°C higher than the melt temperature of the thermoplastic. In another example, the activation temperature is at least 175°C higher than the melt temperature. In yet another example, the temperature is at least 200°C higher than the melt temperature. In the example configurations, these activation temperatures are applied to thermoplastics comprising polyethylene and / or polypropylene, such as LDPE, LLDPE, or HDPE.

[0028] In another example, the activation temperature includes greater than about 300°C, greater than 310°C, greater than 320°C, or greater than 330°C. In a specific example, the thermoplastic is selected from the group consisting of LLDPE, LDPE, HDPE, or PP, and the activation temperature is greater than 300°C. The described thermoplastic may be waste thermoplastic.

[0029] In one example, a metal catalyst a) Increase the melt flow index of thermoplastics. b) Reduce the viscosity of thermoplastics. c) Reduce the average molecular weight of thermoplastics by more than 35%, or d)(a) to (c) any one or more of them.

[0030] In one example, the metal catalyst is selected from the group consisting of group XI transition metal catalysts, group XI transition metal oxide catalysts, copper catalysts, copper oxide catalysts, copper oxide (I), copper oxide (II), copper sulfate (II), silver catalysts, silver oxide (I), silver oxide (II), gold, and metal catalysts having a single s orbital electron in the outer electron shell, metal acetate catalysts, or zinc acetate.

[0031] In one instance, the metal catalyst is copper oxide (I) or copper oxide (II).

[0032] In one instance, the metal catalyst is added at a rate of 0.01% to 100% by weight of the thermoplastic. For example, the metal catalyst can be combined in ratios of at least about 0.01%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or 20% by weight of the thermoplastic.

[0033] In one instance, a metal catalyst is combined with a thermoplastic prior to heating.

[0034] In one instance, a metal catalyst is combined with a thermoplastic during or after heating.

[0035] In one example, molten thermoplastic is heated at an activation temperature.

[0036] In one example, the thermoplastic dispersion is heated at an activation temperature.

[0037] In one instance, the processing steps resulted in an average reduction in the molecular weight of the thermoplastic by more than 30%. In one configuration, the molecular weight of the thermoplastic included less than about 100,000 g / mol, less than 90,000 g / mol, or less than 80,000 g / mol.

[0038] In one instance, thermoplastics and a metal catalyst are added to an extruder.

[0039] In one instance, the melting, dispersing, and / or processing steps are performed within an extruder.

[0040] In one instance, melting involves extensively melting the thermoplastic in an extruder to define the extruder melt zone.

[0041] In one instance, the dispersion stage further includes dispersing the thermoplastic in water under agitation in the emulsification zone of an extruder.

[0042] In one example, the emulsification zone includes a dilution zone for adding additional water. In one example, the ratio of thermoplastic to water is approximately 0.8:1 to 1.8:1.

[0043] In one example, the temperature of the melt zone is between about 140°C and about 240°C, and the temperature of the subsequent zone is lower than that of the melt zone.

[0044] In one instance, a crosslinking agent is added to at least one of a treated thermoplastic and a thermoplastic dispersion to produce an activated thermoplastic adhesive.

[0045] In one example, the crosslinking agent is added in an amount of about 5% to about 50% by weight of the dispersion. In another example, the crosslinking agent is added in an amount of about 10% to about 30% by weight of the dispersion.

[0046] In one instance, the crosslinking agent is selected from organic peroxides or isocyanates.

[0047] In one example, isocyanate is added at 5% to 50% by weight of the adhesive. In another example, isocyanate is added at 5% to 20% by weight of the adhesive.

[0048] In one instance, isocyanate is added at 0.5% to 5% by weight of the plate. In another instance, isocyanate is added at up to 3% by weight of the plate. In yet another instance, isocyanate is added at 1% to 3% by weight of the plate.

[0049] In one instance, the isocyanate is selected from the group consisting of eMDI, pMDI, and diisocyanates.

[0050] In one instance, a thermoplastic composite product can be made by mixing an adhesive from any of the aspects or examples detailed above with fibers to form a composite mixture and applying heat and pressure to the composite mixture in a press or mold to form the thermoplastic composite product.

[0051] In one example, the board contains approximately 70% to 95% fiber by weight of the board. In another example, the board contains approximately 70% to 92% fiber by weight of the board.

[0052] In one instance, the fiber is selected from glass fiber, carbon fiber, aramid fiber, and combinations thereof.

[0053] In one instance, the fiber comprises lignocellulosic material. In one instance, the lignocellulosic material is selected from the group consisting of sawdust, wood fiber, wood pellets, wood chips, wood shavings, coconut shells, straw or rice husks, barley straw, bamboo, palm leaves, or combinations thereof.

[0054] In one example, the composite mixture has a moisture content of about 5% to about 15%.

[0055] In one instance, sources of thermoplastics include high-melting-point thermoplastics such as polypropylene and low-melting-point thermoplastics such as polyethylene, or combinations thereof.

[0056] In one instance, the ratio of high-melting-point thermoplastic to low-melting-point thermoplastic ranged from 1:4 to 4:1.

[0057] In one instance, the source of thermoplastics includes waste thermoplastics.

[0058] In one example, molten thermoplastic is reacted with a coupling agent to produce a functionalized thermoplastic, thereby defining a functionalized phase. The molten thermoplastic may be treated with at least one of heat treatment or catalyst as described above.

[0059] In one instance, the functionalized phase is processed in the functionalization zone of the extruder.

[0060] In one instance, the coupling agent is selected from graft compatibilizers or active hydrogen donors.

[0061] In one instance, the coupling agent is selected from glycidyl methacrylate, maleic anhydride, acrylic acid, glycidyl methacrylate, N-vinylformamide, bismaleimide, or silane.

[0062] In one instance, at least a portion of the thermoplastic is reacted with an initiator in an extruder.

[0063] In one example, the moisture content of the thermoplastic dispersion or adhesive is from about 25% to about 75%.

[0064] In one instance, the plastic particles in the thermoplastic dispersion or adhesive have a length of less than 0.5 mm in any orientation or axis.

[0065] In one example, the thermoplastic is subjected to a pre-processing step, which includes... a) Increase the melt flow index of thermoplastics, for example, by heating to the activation temperature or treating with a catalyst. b) Wash thermoplastics. c) Shred the thermoplastic to reduce the variance of the thermoplastic particle size. d) Standardization of particle size and / or density, e) Granulation to a particle size of 2 mm to 8 mm, or any combination of one or more of f)(a) to (e).

[0066] In one instance, a thermoplastic is subjected to a characterization step that analyzes one or more physical properties of the thermoplastic.

[0067] In one instance, the described method can be used in the following manufacturing process. Lignocellulose thermoplastic composite products, Synthetic fiber composite materials products, or Concrete composite material products.

[0068] In one instance, the described method can be used in the manufacture of a lignocellulosic thermoplastic composite board having the following characteristics. a) Elastic modulus between about 1,000 and about 4,000 MPa b) Fracture modulus of approximately 10 to approximately 25 MPa c) Screw holding force of approximately 200 to approximately 500 N. d) A density of approximately 550 to approximately 1,100 kg / m³, or e)(a) to (d) any combination of one or more of them.

[0069] In one instance, the moisture-resistant composite product contains less than approximately 15%, 14%, 13%, 12%, 11%, or 10% 24-hour swelling.

[0070] In one instance, a moisture-resistant composite material product is provided that does not include moisture-resistant mixtures other than thermoplastic dispersions or adhesives.

[0071] In one instance, the moisture-resistant compound is wax.

[0072] In one instance, the composite mixture has a moisture content of less than 15% before heat and pressure. In another instance, the composite mixture has a moisture content of less than 12% before heat and pressure.

[0073] In one instance, the thermoplastic was derived from waste plastic.

[0074] The invention may also be broadly defined to include portions, elements, and features individually or jointly mentioned or indicated in the description of this application, as well as any or all combinations of any two or more of said portions, elements, or features, and where specific integers mentioned herein have known equivalents in the field to which the invention relates, such known equivalents are considered to be incorporated herein as if separately stated.

[0075] In this specification, when external sources of information (including patent specifications and other documents) are referenced, this is generally for the purpose of providing context for discussing the features of the invention.

[0076] Unless otherwise stated, references to such sources of information in any jurisdiction shall not be construed as an admission that such sources are prior art or part of common general knowledge in the art. Attached Figure Description

[0077] The invention will now be described by way of example only and with reference to the following figures.

[0078] Figure 1a The DSC spectrum of unprocessed LDPE is shown. Figure 1b The DSC spectrum of the rPE membrane after construction is shown. Figure 1c The DSC spectrum of the r-PE film after agricultural processing is shown. Figure 1d The DSC spectrum of recycled LLDPE after consumption is shown. Figure 1e The DSC analysis of post-granulated LDPE in the industrial process is shown.

[0079] Figure 2A(i) shows the average MFI of sample BWT1-4 relative to the average cylinder temperature. Figures 2A(ii) and 2A(iii) show the performance of boards (MOE and MOR, respectively) prepared using heat-treated thermoplastic dispersions from building cladding as adhesives, compared to the control.

[0080] Figures 2B(i) to (iv) show the performance of plates produced using combinations of pMDI crosslinking agent and heat-treated thermoplastic dispersions at different loading levels, compared to the control plate.

[0081] Figure 3a , 3b Figures 3 and 3c show a comparison of melt flow index, viscosity, and molecular weight between the catalyst-treated and heat-treated samples compared to untreated or extruded unprocessed LDPE samples.

[0082] Figures 4A(i) and 4A(ii) show the changes in melt flow behavior and complex viscosity as the amount of CuO catalyst in unprocessed LDPE increases. Figures 4B(i) and 4B(ii) show similar data for recycled LDPE samples. Figures 4C(i) and 4C(ii) show the effect of CuO metering on two forms of recycled linear low-density polyethylene.

[0083] Figure 5A and 5B An example of the method of the present invention is shown.

[0084] Figure 5C and 5D Examples are shown of grafting an active hydrogen donor onto the polymer backbone to form bonds with lignocellulosic material fibers or crosslinking agents.

[0085] Figures 5E to 5S An example of the method of the present invention is shown.

[0086] Figures 6(i) to (iv) show the average MoE, MoR, IB, and thickness swelling of wood fiberboard made from CuO-catalyzed thermoplastic dispersions after a 24-hour immersion test.

[0087] Figures 7a-7e Calibration plots are shown of the natural logarithm of different recycled PP compositions versus the average MFI at different setpoint temperatures from 190°C to 230°C.

[0088] Figures 8a-8c show the average MOE, MOR, and IB of boards made using eMDI and pMDI.

[0089] Figure 9A shows the changes in elastic modulus (MoE), modulus of rupture (MoR), internal bond strength (IB), and swelling ratio (SB) of different plates over 24 hours.

[0090] Figures 10a-10d The MoE, MoR, IB, and 24-h swelling results of composite plates made using different recycled thermoplastic dispersions are shown. Detailed Implementation definition

[0091] As used herein, the terms “cellulose,” “cellulosic,” or their grammatical equivalents refer to processed plant materials, such as paper or cardboard, and do not include lignocellulose materials.

[0092] As used herein, the terms "lignocellulose," "lignocellulosic," or their grammatical equivalents refer to plant materials in which the wood fibers remain substantially intact, such as wood chips, sawdust, wood pellets, wood chips, coconut shells, straw or rice husks, barley straw, bamboo, wood fibers, etc., and do not include cellulose as defined herein. As mentioned herein, lignocellulose materials, lignocellulose-based materials, lignocellulose matrix materials, and lignocellulose fibers will be read interchangeably.

[0093] As used in this specification, the term "comprising" means "consisting of at least in part with". When interpreting a statement in this specification that includes this term, the feature introduced by that term must be present in each statement, but other features may also be present. Related terms such as "comprise" and "comprised" will be interpreted in the same manner.

[0094] As mentioned herein, “waste plastic” means plastic that has been previously used in products or processes for single or multiple uses after the initial synthesis of the plastic polymer. Compared to unprocessed plastic, waste plastic has different properties due to wear and tear from previous use and recycling processes. Waste plastic may have been pre-processed, for example by manual, automatic, or mechanical sorting, washing, or shredding. Waste plastic may originate from household or industrial waste collection services, municipal recycling facilities, or other recycling facilities. In some embodiments, waste plastic may comprise at least one of post-industrial (or pre-consumer) plastic and / or post-consumer plastic and may include recycled plastic.

[0095] As mentioned in this article, "unprocessed plastics" refers to plastics made from plastic resins that have not been previously used in products or processes. They are newly manufactured plastic materials produced directly from petrochemical feedstocks such as natural gas or crude oil, with no recycled plastic content. Because they have not been previously used or processed, unprocessed plastics possess consistent quality and properties. Therefore, they are often chosen for applications where specific structural, aesthetic, or hygiene properties are critical, such as medical devices, high-quality consumer products, or food packaging.

[0096] As mentioned herein, a "dispersion" refers to a system in which particles of one substance (dispersed phase) are dispersed or distributed throughout another substance (dispersion medium). The particle size can be within a certain range. A dispersion can comprise solid particles dispersed in a liquid, a liquid of one density dispersed in another immiscible liquid, or solid particles dispersed within another solid particle. In one example, a dispersion comprises droplets and / or particles of a polymeric material dispersed in water.

[0097] As used herein, "emulsion" means a material comprising a combination of at least two immiscible fractions in a liquid or semi-liquid state or already mixed in a liquid or semi-liquid state. Emulsions according to this disclosure are examples of dispersions and do not necessarily contain two liquids. They will typically contain a polymer in water, wherein the polymer may be a size-reduced cured polymer that has undergone heating and mixing to form the emulsion.

[0098] As mentioned in this article, an "extruder" refers to a machine used to mix and push or pull materials while heating them. An extruder can be a single-screw extruder or a twin-screw extruder, a co-rotating twin-screw extruder, a co-kneader, a Banbury mixer, a high-pressure homogenizer, or any other machine containing an internal screw or rotor to knead or mix materials while applying high pressure and temperature. An extruder typically consists of a heated barrel equipped with a rotating screw or kneading element. The raw material is usually fed into the barrel in granular or pellet form, where it melts and mixes due to the combined action of the screw's mechanical work and the heat from the barrel. The molten plastic is then forced through a die at the end of the barrel, giving it the desired shape.

[0099] As mentioned in this article, “micronization” refers to processing materials to reduce the size of their particles. Micronization can be achieved using a variety of methods, including, for example, extrusion in single-screw or twin-screw extruders, shredding, mechanical grinding, crushing, milling, ultrasonic disintegration, micronization, cryogenic grinding, shearing, high-pressure homogenization, microfluidization, and pulverization.

[0100] We describe a thermoplastic dispersion and / or treated thermoplastic and / or thermoplastic adhesive and their use in forming thermoplastic composite products. In short, these methods involve melting a thermoplastic source and subsequently dispersing the thermoplastic in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles. During this method, the thermoplastic is subjected to a treatment step selected from (a) heating the thermoplastic at an activation temperature, (b) adding a metal catalyst, or both (a) and (b).

[0101] A crosslinking agent can then be added to the treated and / or functionalized thermoplastic or thermoplastic dispersion to produce an adhesive. The crosslinking agent can be added to an extruder or to the extruded functionalized thermoplastic or thermoplastic dispersion. In use, the adhesive can be mixed with fibers to form a composite mixture. The composite mixture can then be formed into a composite product, for example, by introducing it into a press or mold and subjecting it to heat and pressure to form a thermoplastic composite product.

[0102] The inventors have discovered that, according to the methods described herein, waste thermoplastics, when treated and / or functionalized and formed into thermoplastic dispersions, exhibit certain beneficial properties that enable their sustainable and efficient reuse as adhesives. These findings have the potential to transform the chemical recycling industry, enabling the reuse of waste plastics from landfills while simultaneously reducing the use and emissions of fossil fuels associated with the extraction and manufacture of unprocessed plastics.

[0103] Thermoplastics (or thermoplastics) are plastic polymers. Most thermoplastics have a high molecular weight. The polymer chains of thermoplastics are associated by intermolecular forces, which weaken as the temperature rises, producing a viscous liquid. In this state, thermoplastics can be reshaped. Thermoplastics can contain unprocessed plastics, waste plastics, or a mixture of unprocessed and waste plastics.

[0104] The system, method, and apparatus can be used to process a variety of input plastics. In some embodiments, the majority of the input thermoplastic is selected from polypropylene or polyethylene, or combinations thereof. The input thermoplastic may contain at least 60%, 65%, 70%, 75%, 80%, 85%, or 90% polypropylene or polyethylene, or combinations thereof, and suitable ranges may be selected from any of these values ​​(e.g., about 60% to about 90%, about 60% to about 85%, about 60% to about 80%, about 65% to about 90%, about 65% to about 80%, or about 70% to about 90% by weight of the plastic). Polyethylene may comprise 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90% of the thermoplastic by weight, and suitable ranges may be selected from any of these values ​​(e.g., about 55% to about 90%, about 55% to about 80%, about 55% to about 70%, about 60% to about 90%, about 60% to about 85%, about 60% to about 80%, about 65% to about 90%, about 65% to about 80%, or about 70% to about 90% by weight of the plastic).

[0105] Waste plastics provide a usable source of plastic for this method. In many countries, waste plastics contribute to environmental problems as society strives to recycle or dispose of them economically and safely. Sources of waste plastics can be, for example, types of plastics from waste recycling processes. However, it should be understood that various types of input plastics can be used depending on the desired output slurry.

[0106] Problems in processing waste plastics include the variability in polymer type and size, as well as the presence of additives or contaminants. For example, post-consumer waste contains a variety of different polymers and may include organic and inorganic contaminants such as food waste, glass, and foil. A key step in effectively processing waste plastics is to characterize them rapidly and efficiently. Waste plastic processing typically requires knowledge of their physical and chemical properties to optimally apply processing parameters and derive correct stoichiometry.

[0107] Therefore, the methods provided herein may include a waste characterization step, which includes the analysis of one or more physical properties. These physical properties may include melt flow index, melting point, viscosity, glass transition temperature, density, tensile strength, crystallinity, or any combination thereof. Similarly, the methods provided herein may include a waste characterization step, which includes the analysis of one or more chemical properties. These chemical properties may include chemical formula, molecular weight, monomer content, degree of branching, crosslinking density, oxidative stability, or any combination thereof.

[0108] Waste plastics may include any one or a combination of the following: polyethylene terephthalate (PETE or PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), polystyrene or polystyrene foam (PS), polycarbonate, polylactide, acrylic, acrylonitrile butadiene, styrene, fiberglass, rubber, paper, and nylon. This mixture of waste plastics may, for example, originate from blended plastic waste streams. Given the widespread use of plastics in society, waste plastics may originate from daily waste products such as plastic bottles (e.g., milk, carbonated beverage, water bottles, cleaning products), plastic containers (e.g., for industrial products such as oil, food items), and packaging (whether rigid or flexible), although it should be understood that the list of waste products is extremely broad.

[0109] Waste plastics may undergo one or more pre-processing steps. These pre-processing steps can be carried out in a pre-processing facility that includes all the equipment, piping, and controls necessary for the pre-processing of waste plastics. Alternatively, waste plastics may not undergo pre-processing, and the waste plastic stream may not be subjected to any pre-processing prior to any of the downstream steps described herein. Pre-processing facilities for waste plastic sources may include at least one separation step or zone. The separation step or zone may be configured to separate the waste plastic stream into two or more streams rich in certain types of plastics. Such separation can be advantageous when waste plastics undergo chemical recycling steps such as functionalization.

[0110] Some thermoplastics are difficult to recycle or reuse, such as plastic films. Plastic films can be used in the methods described herein, which are important given the lack of other options for recycling them. The ability of the methods described herein to reuse plastic films stems from the extruder's efficient ability to melt, compress, and mix. Additional advantages may include the ability to inject additives or reactive components into the molten plastic and incorporate them into the final product. The methods described herein use extrusion technology to produce an adhesive, which can then be used to manufacture new composite products. One source of plastic can be shredded plastic. That is, it is shredded so that it can be placed inside the inlet of a twin-screw extruder. Various methods for shredding plastic products are known. For example, using cutting and / or extruders, shredders, pelletizers, or grinders. Cutting and extrusion machines (see, for example, U.S. Patent 9,744,689) may include one or more blades rotating within a housing, such that any plastic introduced into the housing is cut into smaller particles by the blades. In some machines, the plastic may begin to melt or partially melt due to the action of the blades (i.e., through heat generated by friction), and this molten or partially molten plastic may enter an extruder, where a screw carries the plastic away from the cutting blades. The plastic can then be extruded and cut into small pellets at the extruder exit. Choppers (see, for example, U.S. Patent 6,241,170), pelletizers (see, for example, U.S. Patent 6,749,138), and grinders (see, for example, U.S. Patent 5,547,136 or German Patent DE 19614030 A1) may include one or more cutting wheels or rollers that, as the plastic passes between the cutting wheels or rollers and the inner surface of the housing, rotate again within the housing and reduce the size of the plastic by the action of the cutting wheels or rollers against the plastic. Alternatively, the plastic may pass between two or more sets of blades or rollers that, in some cases, overlap, such that the plastic is cut or ground by this passage. Such methods typically use rotating blades or bottom blades whose rotation cuts the plastic into smaller particles or fragments.

[0111] It should be understood that plastic waste may include some contaminants. In some embodiments, waste thermoplastics may include some cellulose materials, such as paper and labels. Preferably, the thermoplastics contain less than about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% cellulose material by weight of the thermoplastics, and suitable ranges may be selected from any of these values.

[0112] The functionalization and / or emulsification processes described herein may require the use of pre-processed waste thermoplastics. Functionalization and / or emulsification processes may be required prior to the use of waste plastics (such as plastic films) or thin “shards” of thermoplastics (such as common types of plastic bottles) in the described methods. Granulation of waste plastics prior to processing ensures uniformity in plastic particle size and density, which allows for better control over material flow and melting. Smaller and more uniform particle sizes allow for more efficient melting and mixing during the extrusion process. As used herein, the granulation pre-processing step may include preparing particles with a size of about 2, 3, 4, 5, 6, 7, or 8 mm, and suitable ranges may be selected from any of these values ​​(e.g., about 2 to about 8, 2 to about 6, about 2 to about 5, about 3 to about 8, about 3 to about 7, about 3 to about 6, about 4 to about 8, or about 4 to about 6 mm). When these steps are employed, this can result in more uniform functionalization and emulsification. In addition, the pellets can be fed efficiently at a predetermined rate, which ensures that the stoichiometry is maintained during functionalization and emulsification.

[0113] The inventors have discovered that the melt flow index (MFI) of the thermoplastic to be dispersed is positively correlated with the particle size in any dispersion obtained after the processing steps described herein. A higher MFI results in increased sheet strength, as shown in Example 2B. In one example, the MFI of the thermoplastic to be processed was greater than 8 g / 10 min at 190°C. The inventors have further determined that the MFI of the thermoplastic can be increased after passing through an extruder. Higher melt flow thermoplastics are believed to provide benefits during sheet formation because they melt and spread more efficiently, enhancing the mechanical interlocking between the thermoplastic and the lignocellulosic material.

[0114] The method described herein can provide preprocessing of thermoplastics, which includes steps to increase the melt flow index (MFI) of the thermoplastic. Preprocessing steps can be performed as follows: Before functionalization After functionalization and before emulsification, or Before emulsification in the absence of functionalization.

[0115] Functionalization can include both of the following: a) Functionalizing thermoplastics; and b) Increase the melt flow index.

[0116] When combined with a crosslinking agent, step (a) above can increase the reactivity of the thermoplastic. Step (b) above can lead to improved processing via extruder, enhanced emulsification, and the achievement of smaller particle sizes. The steps to increase the melt flow index (MFI) of the thermoplastic can be performed by any one or more of the following. a) Add a catalyst. b) Add a melt flow index increasing additive to the extruder. The additive may be at least one of a plasticizer and an initiator. The initiator may be an initiator described herein, such as DCP. The plasticizer may be tall oil or a polyolefin-specific plasticizer. c) Applying extruder temperature increases MFI. d) Processing thermoplastics using an extruder to reduce the molecular weight of the thermoplastic molecules. In the presence of branched polymers such as polypropylene, the branched polymers are easier to process in this manner due to the branched nature of the molecules, and the processing reduces the polymer chain length. e) Combining a thermoplastic (such as waste thermoplastic) with a second thermoplastic.

[0117] Step (c) may include combining the thermoplastic with a second thermoplastic having a higher melt flow index. That is, the first thermoplastic may comprise a low-melting-point thermoplastic, and the second thermoplastic may comprise a high-melting-point thermoplastic. The second thermoplastic may comprise polypropylene. The second thermoplastic (comprising the high-melting-point thermoplastic) may constitute 10%, 20%, 30%, 40%, or 50% of the total weight of the thermoplastic, and suitable ranges may be selected from any of these values ​​(e.g., about 10% to about 50%, about 10% to about 40%, about 10% to about 30%, about 20% to about 50%, about 20% to about 49%, or about 30% to about 50% of the total weight of the thermoplastic). Example 8 illustrates the effect of adding different amounts of recycled polypropylene on the melt flow index. This demonstrates that the addition of recycled polypropylene provides a method for increasing the melt flow index of a mixed waste thermoplastic composition.

[0118] As mentioned in this article, high-melting-point thermoplastics include those with a melting point greater than 130°C, and low-melting-point thermoplastics include those with a melting point of 130°C or lower.

[0119] Melt flow index can be increased by processing thermoplastics through an extruder with the addition of an initiator. This can be particularly effective in processing polypropylene, as the initiator extracts hydrogen from the polymer backbone, leading to a decrease in molecular weight through chain breakage. Therefore, in one embodiment, thermoplastics comprising polypropylene can be processed to increase the melt flow index by using an extruder. In this example, the initiator can be added to the extruder or feed material before entering the extruder.

[0120] Figure 6A shows an example of the method as described herein, wherein: Functionalizing thermoplastics in an extruder to form functionalized thermoplastics. Alternatively, additional processing steps may be used, including heat treatment or the introduction of a catalyst. Functionalized and optionally treated thermoplastics are combined with crosslinking agents and substrates in a mixer to form an adhesive mixture. The adhesive mixture is formulated into mats for pressing in a press, and Heat and pressure are applied to the felt to produce composite products.

[0121] Composite products can undergo post-processing, such as cutting or lamination, to form usable products. Thermoplastics may have already undergone at least one of pre-processing (e.g., washing or sorting) and / or characterization steps. As shown in Figure 6B, thermoplastics may not undergo functionalization in an extruder. Thermoplastics may have already been functionalized, or functionalization may not be required to provide usable composite products. Figure 6B illustrates an example of the method described herein, wherein: At least a portion of the thermoplastic is melted extensively, optionally processed, and combined with water in an extruder to form a thermoplastic dispersion. Optional processing steps may include heat treatment or the introduction of a catalyst. The dispersion is mixed with a crosslinking agent and a substrate in a mixer to form an adhesive mixture. The adhesive mixture is formulated into mats for pressing in a press, and Heat and pressure are applied to the felt to produce composite products.

[0122] Composite products may undergo post-processing, such as cutting or lamination, to form usable products. Thermoplastics may have already undergone at least one of the pre-processing (e.g., washing or sorting) and / or characterization steps.

[0123] Examples 7-13 illustrate various examples of producing thermoplastic dispersions for the preparation of composite panels.

[0124] As shown in Figure 6C, thermoplastics can undergo both functionalization (to form functionalized thermoplastics) and dispersion (to form thermoplastic dispersions). Figure 6C illustrates an example of the method described herein, wherein: Functionalizing thermoplastics in an extruder to form functionalized thermoplastics. Alternatively, additional processing steps may be used, including heat treatment or the introduction of a catalyst. At least a portion of the functionalized thermoplastic is melted extensively and combined with water in an extruder to form a thermoplastic dispersion. Thermoplastic dispersions are combined with crosslinking agents and substrates in a mixer to form adhesive mixtures. The adhesive mixture is formulated into mats for pressing in a press, and Heat and pressure are applied to the felt to produce composite products.

[0125] Composite products may undergo post-processing, such as cutting or lamination, to form usable products. Thermoplastics may have already undergone at least one of the pre-processing (e.g., washing or sorting) and / or characterization steps.

[0126] Examples 7-13 illustrate the efficient production of adhesives and their use in the preparation of composite panels.

[0127] It should be understood that the adhesive mixtures mentioned herein can be used to prepare a range of composite materials or adhesives, such as those described below. In one embodiment, the substrate comprises a lignocellulose material / substrate.

[0128] In some instances, sourced or unprocessed thermoplastics are treated to obtain treated thermoplastics. Compared to untreated, sourced, waste, or unprocessed thermoplastics, the treated thermoplastics exhibit certain properties that synergistically work with downstream process steps and composition components to provide enhanced thermoplastic dispersions. For example, when bonded to fibers within composite materials such as composite sheets, thermoplastic dispersions with smaller particle sizes provide enhanced dispersion stability and adhesion properties. In some instances, these improved downstream properties of the dispersion and sheet are achieved when the adhesive contains particulate thermoplastics with an average particle size of less than 0.5 mm. i) Melt flow index greater than 8 g / 10 min at 190°C ii) Complex viscosity less than 5,000 Pa·s at 160°C iii) The average molecular weight is reduced by more than 30% relative to the source, untreated, or unprocessed thermoplastic, or any one or more of (iv)(i) to (iii).

[0129] In one example, a crosslinking agent is added to at least one of a treated thermoplastic and a thermoplastic dispersion to produce an activated thermoplastic adhesive. The inventors have discovered that using an isocyanate-based crosslinking agent provides an adhesive with properties of adhering to and integrating with a fibrous substrate, thus providing synergistically enhanced adhesive properties. When the adhesive is used within the composite panel as shown in Example 6, this combination of the treated thermoplastic, moisture, and crosslinking agent produces a composite product with unexpectedly superior performance compared to a control.

[0130] In one example, isocyanate is added at 5% to 20% by weight of the adhesive. In another example, isocyanate is added at 5% to 50% by weight of the adhesive.

[0131] In one instance, the isocyanate is selected from the group consisting of pMDI (polymerized methylene diphenyl diisocyanate), eMDI (emulsified methylene diphenyl diisocyanate), and diisocyanates.

[0132] Figure 6D shows an example of the method as described in this paper, wherein: Thermoplastics are processed in an extruder to form treated thermoplastics. Thermoplastics can be optionally functionalized before, during, or after processing. Treatment may include heat treatment or the introduction of a catalyst to increase MFI. The treated thermoplastic is combined with a crosslinking agent and a substrate in a mixer to form an adhesive mixture. The adhesive mixture is formulated into mats for pressing in a press, and Heat and pressure are applied to the felt to produce composite products.

[0133] Composite products may undergo post-processing, such as cutting or lamination, to form usable products. Thermoplastics may have already undergone at least one of the pre-processing (e.g., washing or sorting) and / or characterization steps.

[0134] As shown in Figure 6E, thermoplastics can be processed in an extruder before, during, or after dispersing the thermoplastic in water. The thermoplastic may have been functionalized, or functionalization may not be required to provide a usable composite product. Figure 6E illustrates an example of the method described herein, wherein: At least a portion of the thermoplastic is melted, processed, and combined with water in an extruder to form a thermoplastic dispersion. Thermoplastics are treated before, during, or after being combined with water, wherein the treatment may include heat treatment or the introduction of a catalyst to increase MFI. The dispersion is mixed with a crosslinking agent and a substrate in a mixer to form an adhesive mixture. The adhesive mixture is formulated into mats for pressing in a press, and Heat and pressure are applied to the felt to produce composite products.

[0135] Composite products may undergo post-processing, such as cutting or lamination, to form usable products. Thermoplastics may have already undergone at least one of the pre-processing (e.g., washing or sorting) and / or characterization steps.

[0136] Examples 7-13 illustrate various examples of producing thermoplastic dispersions for the preparation of composite panels.

[0137] As shown in Figure 6F, thermoplastics can undergo both treatment (to form treated thermoplastics) and dispersion (to form thermoplastic dispersions). Thermoplastics can optionally undergo functionalization before, during, or after treatment. Figure 6F illustrates an example of the method as described herein, wherein: Thermoplastics are processed in an extruder to form treated thermoplastics, which are optionally functionalized before, during, or after the processing. At least a portion of the treated thermoplastic is melted extensively and combined with water in an extruder to form a thermoplastic dispersion. Thermoplastic dispersions are combined with crosslinking agents and substrates in a mixer to form adhesive mixtures. The adhesive mixture is formulated into mats for pressing in a press, and Heat and pressure are applied to the felt to produce composite products.

[0138] Composite products may undergo post-processing, such as cutting or lamination, to form usable products. Thermoplastics may have already undergone at least one of the pre-processing (e.g., washing or sorting) and / or characterization steps.

[0139] One form of processing thermoplastics involves mixing them at temperatures significantly above their melting point. This can be done in a mixing container or an extruder. It should be understood that the standard processing temperature of the thermoplastic in the extruder will be equal to or slightly above the plastic's melting temperature. This ensures the thermoplastic melts while minimizing energy consumption. The inventors unexpectedly discovered that when higher temperatures are used, the melt flow index increases in a non-linear manner, indicating a fundamental change in the structure of the processed thermoplastic.

[0140] Example 2a illustrates how the melt flow index (MFI) increases with increasing processing temperature. Figure 2a shows the non-linear increase in MFI. Figure 2b shows the unexpected increase in plate properties observed as processing temperature increases.

[0141] To avoid being bound by theory, this effect is considered to be due to the thermoplastic reaching the activation temperature at which polymer chain breakage occurs or begins to dominate the crosslinking reaction. Different thermoplastics have different degrees of branching, so different amounts of side chains can affect the activation temperature for chain breakage.

[0142] Therefore, in one example, the present invention provides a method for processing thermoplastics, comprising heating the thermoplastic to an activation temperature equal to or higher than its chain rupture temperature. In this context, the activation temperature is a temperature setpoint where a heating device, such as an extruder, is set to achieve heating of the thermoplastic. In one example, the activation temperature is at least 150°C higher than the melt temperature. In another example where the chain rupture temperature is even higher, the activation temperature is at least 175°C higher than the melt temperature. In yet another example where the polymer exhibits a higher degree of branching, the temperature is at least 200°C higher than the melt temperature.

[0143] In another example, the activation temperature can be expressed as an absolute temperature, although this will vary for different thermoplastics with different degrees of branching and melt temperatures. For polyolefins, including LDPE, HDPE, LLDPE, and PP, the activation temperature can be greater than about 300°C. For some more highly branched polyolefins, the activation temperature can be greater than 310°C. In some instances, the temperature can be greater than 320°C or greater than 330°C. In one specific example, the thermoplastic includes LDPE film and the activation temperature is greater than 300°C. Thermoplastics can be waste plastics.

[0144] In some instances, the methods described herein can be used to process a variety of different thermoplastics that may contain waste thermoplastics. The activation temperature for such alternative thermoplastics can vary and can be determined by those skilled in the art with reference to the experimental procedures outlined in Example 2 (where MFI is measured at different activation temperatures). In some instances, the activation temperatures for different thermoplastics include the following:

[0145] Therefore, in one example, a method is provided for treating thermoplastics to increase the melt flow index (MFI). In one example, the MFI is defined as greater than 8 g / 10 min at 190°C. In another example, the MFI is defined as greater than 10 or 15 g / 10 min at 190°C.

[0146] Another treatment for thermoplastics is to treat them with a catalyst that increases MFI. Example 3 illustrates a screening test for potential catalysts. In this example, a catalyst was added to an extruder containing waste plastics and the MFI was measured. Figure 3a The results show that copper oxide (I) (CuO) and copper oxide (II) (Cu2O) have a surprisingly beneficial effect on the MFI of the treated plastics.

[0147] Examples 4a and 4b investigated the metered addition of the catalyst for the catalyst of interest. It can be seen that even when applied at concentrations of thermoplastics ranging from approximately 0.1% to at least 3% w / w, the copper oxide catalyst exhibits a significant MFI-increasing effect. Example 4A demonstrates that the catalyst is operated at concentrations less than 0.1%, for example, greater than 0.01%, to reduce the MFI.

[0148] Therefore, in one example, a method is provided for treating thermoplastics to increase the melt flow index, wherein the treatment includes processing the thermoplastics with a catalyst that increases the melt flow index.

[0149] The catalyst can be selected from the group consisting of metals with a single s orbital electron in the outer electron shell, group XI transition metal catalysts, group XI transition metal oxide catalysts, copper catalysts, copper oxide catalysts, copper oxide (I), copper oxide (II), copper sulfate (II), silver catalysts, silver oxide (I), silver oxide (II), gold catalysts, metal acetate catalysts, or zinc acetate.

[0150] Examples 4a and 4b investigated the metered addition of the catalyst for the catalyst of interest. It was found that even when applied at a concentration of 0.1% w / w thermoplastic, the copper oxide catalyst exhibited a significant increase in MFI.

[0151] The catalyst can be combined with the thermoplastic material before or during mixing, for example, in an extruder. In one example, the catalyst is combined with the thermoplastic material at a ratio of 0.01% to 100% w / w. For example, the catalyst is combined at a ratio of at least about 0.01%, 1%, 3%, 5%, 8%, 10%, or 20%.

[0152] Not wanting to be bound by theory, it is believed that Cu in copper(II) oxide, as a group XI transition metal, 2+ It is easily reduced to Cu due to its electronic configuration. +1 C 2+ The electronic configuration places a single electron in a high-energy d-orbital to become the more energy-stable Cu. 1+ Therefore, in the presence of atmospheric oxygen, Cu 2+ To Cu 1+ The reduction reaction attacks the CH bonds in LDPE and generates hydroxyl radicals, which in turn promote chain scission in LDPE. Reduced Cu 1+ It is very likely that it will be oxidized again to Cu at elevated temperatures. 2+ This also facilitates catalytic cycle transfer. Similar high-temperature redox behavior is expected to be observed in other Group XI metals such as Ag and Au.

[0153] Another hypothesis regarding the observed effectiveness of copper oxide rather than copper sulfate is that copper oxide outperforms other catalysts due to Lewis theory. Sulfate and oxide anions are classified as hard bases. However, oxides are harder bases than sulfates because they are smaller and less readily polarized. Copper ions are classified as soft acids and therefore have stronger interactions with softer ions such as sulfate. This means that copper sulfate is more stable than copper oxide, and therefore copper oxide will more easily separate into copper and oxide ions.

[0154] The methods described herein may include functionalizing the thermoplastic during the preparation of the adhesive to improve its reactivity with a crosslinking agent. This functionalization may be performed with or without the processing steps described herein, such as heat treatment or catalytic treatment. All previously proposed examples of heat and catalytic treatments may be combined with functionalization to obtain the thermoplastic adhesive as described. Figure 5A and 5B Examples of the invention are shown. Adhesives can be used in a variety of applications, such as in combination with lignocellulosic materials / substrates to form plastic composite products.

[0155] The method described herein can produce composite materials comprising: Thermoplastic material is introduced into the extruder; Thermoplastics may be treated with heat treatment or catalytic treatment. Reacting thermoplastics with coupling agents to form functionalized thermoplastics; Functionalized thermoplastics are formulated with crosslinking agents to form adhesives; and The adhesive is mixed with a cellulose matrix to form a composite material mixture.

[0156] The method may further include heating and pressing the composite mixture to produce composite products.

[0157] Most plastic waste, especially PP and PE, is hydrophobic. Lignocellulosic fibers are hydrophilic. Therefore, combining the two can be difficult. Coupling agents, such as graft compatibilizers, can be used, which have both hydrophobic and hydrophilic functional groups and thus enable crosslinking agents to bond with thermoplastics.

[0158] This allows the thermoplastic introduced into the extruder to melt extensively in the melt zone of the extruder. The coupling agent can optionally be added to the molten thermoplastic in the melt zone in combination with heat treatment or catalytic treatment. Functionalization of thermoplastic waste with coupling agents can occur simultaneously or sequentially in multiple extruders or modular extruders within the extruder. Similarly, heat or catalytic treatment can occur simultaneously or sequentially in multiple extruders or modular extruders within the extruder.

[0159] Without being bound by theory, differences exist between the chemical structures and / or polarities of thermoplastic polymers and lignocellulosic fibers. These differences can lead to weak interfacial adhesion. For example, polyolefins are hydrophobic and lignocellulosic fibers are hydrophilic, meaning they repel each other. Weak interfacial adhesion can result in lower tensile strength and weaker thermoplastic composite products, leading to weaker end products such as plastic-lignocellulosic composite boards. Coupling agents can be added with functional groups that provide available hydrogen, or grafted onto the polymer to alter its polarity and create favorable interactions with the lignocellulosic material. These favorable interactions with the lignocellulosic material can result in stronger interfacial adhesion. In the case of crosslinking agents, the coupling agent can form bonds with the crosslinking agent.

[0160] At least one coupling agent can be added to the extruder along with the thermoplastic. This coupling agent can be added before heating and operating the extruder. Alternatively, it can be added after initial heating and operation of the extruder.

[0161] The amount of each coupling agent added may be about 1%, 2%, 3%, 4% or 5% by weight of thermoplastic, and a suitable range may be selected from any of these values ​​(e.g. about 1% to about 5%, about 1% to about 4%, about 1% to about 3%, about 2% to about 5%, about 2% to about 4%, about 3% to about 5% or about 3% to about 4% by weight of thermoplastic).

[0162] When adding different types of coupling agents, the total amount of the added coupling agent may be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% by weight of the thermoplastic, and a suitable range may be selected from any of these values ​​(e.g., about 2% to about 10%, about 2% to about 8%, about 2% to about 7%, about 3% to about 10%, about 3% to about 9%, about 3% to about 7%, about 3% to about 6%, about 4% to about 10%, about 4% to about 9%, about 4% to about 8%, about 5% to about 10%, about 5% to about 9%, about 5% to about 8%, about 6% to about 10%, about 6% to about 8%, about 7% to about 10% or about 7% to about 9% by weight of the thermoplastic).

[0163] The degree of functionalization of a polymer backbone refers to the extent to which functional groups are attached to the polymer backbone. In polymer chemistry, a functional group is a specific group of atoms within a molecule that is responsible for the molecule's characteristic chemical reactions. The degree of functionalization quantifies how many of these groups are attached to the polymer. For example, in a functionalized polymer, not every repeating unit may have the attached functional group. As mentioned herein, the degree of functionalization represents the percentage of repeating units in the polymer that have been functionalized. The degree of functionalization is controlled during reactive extrusion processes.

[0164] A method for preparing a functionalized thermoplastic, or a method for producing a functionalized thermoplastic using the method described herein, wherein the functionalized thermoplastic has a degree of functionalization ranging from 0.5%, 1%, 2%, 3%, 4%, 5%, or 6%, and suitable ranges may be selected from any of these values ​​(e.g., about 0.5% to about 6%, about 0.5% to about 5%, about 0.5% to about 4%, about 0.5% to about 2%, about 1% to about 6%, about 1% to about 5%, about 1% to about 4%, about 2% to about 6%, about 2% to about 5%, about 3% to about 6%, or about 3% to about 4%). The functionalized thermoplastic may comprise PE or PP or a mixture of PE and PP. Methods for measuring the degree of functionalization will be known to those skilled in the art. For example, the method may include the use of FTIR and / or acid-base titration.

[0165] In one example, the coupling agent comprises the monomer GMA (glycidyl methacrylate). GMA can be added to the extruder simultaneously or continuously with the thermoplastic via feed. In one example, GMA is added to the melt zone of the extruder via a syringe. The amount added depends on the desired degree of functionalization. GMA can be added in the range of 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% by weight of the thermoplastic, and suitable ranges can be selected from any of these values ​​(e.g., about 2% to about 10%, about 2% to about 8%, about 2% to about 7%, about 3% to about 10%, about 3% to about 9%, about 3% to about 7%, about 4% to about 10%, about 4% to about 9%, about 4% to about 8%, about 5% to about 10%, about 5% to about 8%, or about 6% to about 10% by weight of the thermoplastic). Adding a higher proportion of coupling agent may result in undesirable phase separation, where the relatively hydrophilic and hydrophobic reactants hinder effective mixing. In this case, undesirable homopolymerization may occur, leading to monomer self-reaction or polymer degradation, and impaired monomer miscibility / miscibility.

[0166] In one example, the present invention includes the functionalization of recycled polypropylene using GMA. Analysis shows that the processed GMA-functionalized polypropylene has a smaller particle size than the unfunctionalized material. When the material is processed by an extruder to achieve the emulsification and production of thermoplastic dispersions, the smaller particle size is expected to result in a reduction in particle size within the resulting thermoplastic dispersion, and subsequently, increased strength in wood fiberboard containing dispersions with crosslinking agents such as isocyanates.

[0167] Coupling agents can be added to the extruder as powders or other forms of solids. Coupling agents can be selected from graft compatibilizers, active hydrogen donors, or combinations thereof.

[0168] Grafted comonomers can be used to increase the affinity between coupling agents and thermoplastics. Styrene can be used to bridge monomers and polymers because it has an affinity for both and acts as a cosolvent.

[0169] Graft compatibilizers promote adhesion between immiscible or incompatible components in blends or composites. A lack of compatibilization can lead to poor mechanical properties in the final product. For example, graft compatibilizers can improve the cohesiveness between inherently hydrophilic wood chips and inherently hydrophobic PP / PE. Graft compatibilizers work by grafting chemical groups onto the polymer backbone, altering the fundamental characteristics of the polymer chain and thus making it "compatible" with the composite components. Graft compatibilizers possess functional groups compatible with each component in the composite. In this way, they can "anchor" themselves between these two incompatible components and reduce interfacial tension, promoting finer dispersion and better adhesion between the components.

[0170] Coupling agents or graft compatibilizers can be selected from maleic anhydride, acrylic acid, glycidyl methacrylate, N-vinylformamide, bismaleimide, or silanes. The use of N-vinylformamide can increase flexural strength and modulus. Silane graft compatibilizers can be selected from vinyltriethoxysilane or γ-aminopropyltriethoxysilane. Graft compatibilizers can also be selected from titanate coupling agents.

[0171] Maleic anhydride (MA) can be used as a grafting compatibilizer or coupling agent to form maleicized polyethylene or maleicized polypropylene. Maleicized polyethylene is formed by reacting polyethylene with maleic anhydride. Maleicized polypropylene is formed by reacting polypropylene with maleic anhydride. During the manufacture of composite panels, the anhydride functional groups of MA can interact with the surface hydroxyl groups of wood or lignocellulose polymers. Similarly, during the manufacture of composite panels, the carbon chains of maleate copolymers can crosslink with the unfunctionalized polymer matrix due to their similar polarity. Sufficient maleic anhydride can be added to form maleicized thermoplastics. Not wishing to be limited by theory, during the manufacture of composite panels, maleic anhydride can form bonds with the hydroxyl groups on lignocellulose fibers. The hydroxyl groups can react with one of the carbonyl groups on the maleic anhydride, forming a covalent bond between the lignocellulose oxygen and one of the carbonyl carbons on the maleic anhydride. This can lead to ring opening and the formation of a carboxylic acid moiety at another carbonyl group. The resulting carboxylic acid can then form additional bonds with another hydroxyl group of the lignocellulose material or with a crosslinking agent such as diisocyanate. The polymer chains attached to maleic acid can then form favorable interactions with the non-maleic acid-modified plastic matrix through chain entanglement, resulting in stronger interfacial adhesion. Hydrogen bonding between the hydroxyl groups of lignocellulose and the hydroxyl groups of carboxylic acids can also contribute to these favorable interactions.

[0172] The inventors conducted experiments to produce composite wood fiberboard using maleic anhydride-functionalized polyethylene (MAPE) and Luperox 231 as crosslinking agents. The adhesive was prepared by blending and emulsifying LDPE to prepare a thermoplastic dispersion. Results showed that boards with MAPE exhibited significantly higher MoE strength compared to those without. Examples demonstrate that MAPE improves the adhesion of LDPE to wood fibers during the preparation of composite boards.

[0173] The amount of graft compatibilizer added may be about 1%, 2%, 3%, 4% or 5% by weight of thermoplastic, and a suitable range may be selected from any of these values ​​(e.g. about 1% to about 5%, about 1% to about 4%, about 1% to about 3%, about 2% to about 5%, about 2% to about 4%, about 3% to about 5% or about 3% to about 4% by weight of thermoplastic).

[0174] In one embodiment, glycidyl methacrylate is used as a graft compatibilizer or coupling agent to form a functionalized thermoplastic.

[0175] Initiators can be added together with grafting compatibilizers and functionalizing agents, or simultaneously with heat or catalytic treatment. Initiators are added to promote thermal dissociation and generate free radicals to promote grafting or adhesion between lignocellulosic raw materials and binder or crosslinking agent molecules. In one example, the initiator comprises a free radical generating initiator.

[0176] The use of initiators in combination with the functionalization of thermoplastics has been explored. Thermoplastics can be functionalized with glycidyl methacrylate (GMA), wherein the thermoplastic can be a high-melting-point thermoplastic such as polypropylene and a low-melting-point thermoplastic such as polyethylene, or a combination thereof. The inventors have found that processing high-melting-point thermoplastics such as PP in the presence of an initiator results in increased melt flow. This provides enhanced size reduction and better emulsification of the waste plastic.

[0177] The method described herein can provide a thermoplastic dispersion comprising an initial step of processing a high-melting-point thermoplastic such as PP in the presence of an initiator, followed by combining the high-melting-point thermoplastic such as PP with a low-melting-point thermoplastic such as PE in an extruder prior to emulsification to prepare the thermoplastic dispersion as described herein. The high-melting-point thermoplastic such as polypropylene, or the low-melting-point thermoplastic such as polyethylene, or both may optionally be functionalized. The ratio of the high-melting-point thermoplastic (such as polypropylene) to the low-melting-point thermoplastic (such as polyethylene) can be from 1:4 to 4:1, and suitable ranges may be selected from any of these values ​​(e.g., about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, or about 1:4).

[0178] In the context of emulsion-based processes, it has been found to be preferable to minimize the viscosity difference between phases (such as polymer and water), as this results in smaller particle sizes within the emulsion. Adding high-melting-point thermoplastics such as polypropylene to form thermoplastic compositions is an example of this, as illustrated in Examples 8 and 9. Higher melt flow rates of thermoplastics also provide benefits during sheet formation, as they melt and spread more efficiently, enhancing the mechanical interlocking between the plastic and the lignocellulosic material. Furthermore, the hydrophilic properties of GMA promote better adhesion to the lignocellulosic material, facilitating closer mixing.

[0179] The advantages of GMA grafting extend beyond the emulsification process. The hydrophilic properties of GMA help reduce surface tension between immiscible phases, resulting in smaller droplets and finer dispersions. Furthermore, GMA and maleic anhydride (MAH) act as potential compatibilizers, potentially improving the uniformity of the blend, which can positively influence melt flow and other aspects.

[0180] The initiator can be selected from organic peroxides, such as benzoyl peroxide, dicumyl peroxide, octanoyl peroxide, lauroyl peroxide, stearyl peroxide, cumene hydroperoxide, tert-butyl peroxide, tert-butyl peroxylaurate, tert-butyl isopropyl peroxycarbonate, tert-butyl peracetate, and diisopropylbenzene hydroperoxide. The initiator may contain thermoplastics irradiated with UV or electron beam.

[0181] The initiator can be selected from dicumyl peroxide and dicumylene.

[0182] Furthermore, functionalization can be achieved using groups that provide "active hydrogen." The active hydrogen donor is a coupling agent and can be selected from acids such as acrylic acid and itaconic acid, or alcohols such as polyvinyl alcohol. Figure 5C and 5D As shown, if included, an active hydrogen donor may be grafted onto the polymer backbone to form bonds with the lignocellulosic material fibers or to form covalent bonds with a crosslinking agent.

[0183] The amount of the added active hydrogen donor or coupling agent may be about 1%, 2%, 3%, 4% or 5% by weight of the thermoplastic, and a suitable range may be selected from any of these values ​​(e.g. about 1% to about 5%, about 1% to about 4%, about 1% to about 3%, about 2% to about 5%, about 2% to about 4%, about 3% to about 5% or about 3% to about 4% by weight of the thermoplastic).

[0184] Suitable active hydrogen donors can be selected from compounds containing at least one reactive functional group for isocyanates and a functional group suitable for grafting onto the polyolefin backbone. The reactive functional group for isocyanates is a reactive functional group containing reactive, active, or Zerewitinoff active hydrogen.

[0185] Where compounds having isocyanate reactive functional groups are not suitable for grafting onto polyolefins, those skilled in the art will understand that the compounds can be modified to be suitable for grafting, such as by incorporating olefin functional groups or short-chain olefin side chains. Examples of coupling agent compounds containing isocyanate active hydrogen atoms include alcohols, glycols, thiols, carboxylic acids such as polyacids, amines, ureas, silanes, and amides.

[0186] The active hydrogen donor can be selected from compounds that provide acidic, alcoholic, or amine functional groups. Not wishing to be limited by theory, groups with available hydrogen can bond with hydroxyl hydrogens on wood fibers, which also produces a favorable but weaker interaction. Groups with available hydrogen also provide the necessary hydrogen and subsequent interaction to form urethane bonds with diisocyanates.

[0187] Preferred active hydrogen donors or coupling agents are selected from short- to medium-chain compounds containing at least one of the functional groups of olefins and alcohols, carboxylic acids, or amines. This may include vinyl alcohol, acrylic acid, or itaconic acid.

[0188] Examples of suitable active hydrogen donors or coupling agents containing carboxylic acid functional groups for grafting include methacrylic acid, acrylic acid, maleic acid or its monoesters (such as monomethyl maleate), maleic anhydride, ethylacrylic acid, fumaric acid or its monoesters (such as monomethyl fumarate), crotonic acid, itaconic acid or its monoesters (such as monomethyl itaconic acid), itaconic anhydride, vinyl sulfonic acid, 2-methacryloyloxy-ethane sulfonate, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), vinylphosphonic acid, etc. 2-(methacryloyloxy)ethyl phosphate, citrate, citric acid or their monoesters (such as monomethyl citrate), pentenediaic acid or its monoesters (such as monomethyl pentenediaic acid), methyl maleic acid or its monoesters (such as monomethyl methyl maleate), methyl maleic anhydride, citrate anhydride, pentenediaic anhydride, intracyclic bicyclic [2,2,1]-5-heptene-2,3-dicarboxylic acid or its monoesters (such as monomethyl esters of hepten-2,3-dicarboxylic acid) and intracyclic bicyclic [2,2,1]-5-heptene-2,3-dicarboxylic anhydride.

[0189] Active hydrogen donors suitable for grafting may include olefin derivatives of the following: glycols, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol and other pentanediols, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, other 2-ethyl-hexanediols, 1,6-hexanediol and other hexanediols, 2,2,4-trimethylpentane-1,3-diol, decanediol, dodecanediol, bisphenol A, hydrogenated bisphenol A, 1,4-cyclohexanediol, 1,4-bis(2-hydroxyethoxy)cyclohexane, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-bis(2-hydroxyethoxy)benzene, ester diol 204 (available from TCI Corporation, USA). (American) propionic acid, 3-hydroxy-2,2-dimethyl, 3-hydroxy-2,2-dimethylpropyl ester.

[0190] Suitable amines for grafting include olefin derivatives of the following: N-methylethanolamine, N-methylisopropylamine, 4-aminocyclohexanol, 1,2-diaminoethane, 1,3-diaminopropane, diethylenetriamine, toluene-2,4-diamine, and toluene-1,6-diamine. Aliphatic compounds containing 2 to 8 carbon atoms are preferred. Ethylenediamine, monoethanolamine, and propylenediamine are also suitable.

[0191] Other acids suitable for grafting include olefin derivatives of the following: bis(hydroxymethyl)propionic acid, diaminobenzoic acid, bis(hydroxymethyl)acetic acid, 2,2,2-tris(hydroxymethyl)acetic acid, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butyric acid, 2,2-bis(hydroxymethyl)valerate, 2,5-dihydroxy-3-methylvalerate, 3,5-dihydroxy-3-methylvalerate, 4,5-dihydroxy-3-methylvalerate, 3,4-dihydroxy-3-methylvalerate, 2,3-dihydroxy-3-methylvalerate, 2,4-dihydroxy-3-methylvalerate, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid. Benzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,3-dihydroxysuccinic acid, 2,5-diaminovaleric acid, 3,5-diaminovaleric acid, 4,5-diaminovaleric acid, 2,3-dihydroxybenzenesulfonic acid, 3,4-dihydroxybenzenesulfonic acid, 2,4-dihydroxybenzenesulfonic acid, 2,5-dihydroxybenzenesulfonic acid, 3,5-dihydroxybenzenesulfonic acid, 2,3-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 2,4-diaminobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, 3,5-diaminobenzenesulfonic acid, 3,4-dihydroxy-2-toluenesulfonic acid, 3,4-diamino-2-toluenesulfonic acid, 4,5-dihydroxy-2-toluenesulfonic acid, 4,5-diamino-2-toluenesulfonic acid, 5, 6-Dihydroxy-2-toluenesulfonic acid, 5,6-diamino-2-toluenesulfonic acid, 3,5-dihydroxy-2-toluenesulfonic acid, 3,5-diamino-2-toluenesulfonic acid, 3,6-dihydroxy-2-toluenesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, 4,6-dihydroxy-2-toluenesulfonic acid, 4,6-diamino-2-toluenesulfonic acid, 2,4-dihydroxy-3-toluenesulfonic acid, 2,5-dihydroxy-3-toluenesulfonic acid, 2,5-diamino-3-toluenesulfonic acid, 2,6-dihydroxy-3-toluenesulfonic acid, 2,6-diamino-3-toluenesulfonic acid, 4,5-dihydroxy-3-toluenesulfonic acid, 4,5-diamino-3-toluenesulfonic acid, 4 ,6-Dihydroxy-3-toluenesulfonic acid, 4,6-diamino-3-toluenesulfonic acid, 5,6-dihydroxy-3-toluenesulfonic acid, 5,6-diamino-3-toluenesulfonic acid, 2,3-dihydroxy-4-toluenesulfonic acid, 2,3-diamino-4-toluenesulfonic acid, 2,5-dihydroxy-4-toluenesulfonic acid, 2,5-diamino-4-toluenesulfonic acid, 2,6-dihydroxy-4-toluenesulfonic acid, 2,6-diamino-4-toluenesulfonic acid, 3,5-dihydroxy-4-toluenesulfonic acid, 3,5-diamino-4-toluenesulfonic acid, 3,6-dihydroxy-4-toluenesulfonic acid, 3,6-diamino-4-toluenesulfonic acid, 5,6-dihydroxy-4-toluenesulfonic acid, 5,6-diamino-4-toluenesulfonic acid.

[0192] The initiator can be added together with an active hydrogen donor. Adding the initiator and undergoing thermal dissociation to generate free radicals facilitates and promotes grafting. In one configuration, the initiator is selected from organic peroxides, such as benzoyl peroxide, dicumyl peroxide, octanoyl peroxide, lauroyl peroxide, stearyl peroxide, cumene hydroperoxide, tert-butyl peroxide, tert-butyl peroxylaurate, tert-butyl isopropyl peroxycarbonate, tert-butyl peracetate, and diisopropylbenzene hydroperoxide.

[0193] The initiator can be selected from dicumyl peroxide. The initiator can be combined with the material before being fed into the extruder. Alternatively or additionally, the initiator can be injected into the extruder in the melt zone or after the melt zone. The initiator is preferably injected after effective mixing of the polymer and coupling agent to ensure uniform dispersion and efficient free radical generation. The initiator can be dissolved in the coupling agent (e.g., GMA) or a suitable organic solvent (e.g., in the case of maleic anhydride, since it is solid at room temperature).

[0194] The method described herein results in the production of thermoplastic dispersions or emulsions. The emulsion can be prepared from different portions of a thermoplastic, wherein one portion of the thermoplastic has been functionalized with a coupling agent / functionalizing agent to form a functionalized thermoplastic fraction, and another portion can be a non-functionalized thermoplastic that has not yet undergone the process of functionalization. The resulting thermoplastic dispersion or emulsion may contain granulated thermoplastic, wherein approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% by weight of the granulated thermoplastic in the emulsion is functionalized thermoplastic, and the remainder of the thermoplastic (if any) is non-functionalized. Therefore, only a portion of the waste used for downstream adhesive production purposes can be functionalized, and this has been found to have beneficial effects in terms of processing speed and efficiency as well as the cost of functionalizing agents.

[0195] Functionalized thermoplastics for processing in the emulsification zone by an extruder or TSE can be prepared by the first module of the extruder or TSE that provides the melt and functionalization of the thermoplastic.

[0196] Some or all of the functionalized thermoplastics can be obtained from commercially available compatibilized thermoplastics, such as compatibilized PE functionalized, for example, with maleic anhydride. The inventors have demonstrated the production of composite sheets containing functionalized thermoplastics.

[0197] Commercially available compatibilized thermoplastics can be mixed with nonfunctionalized thermoplastics already processed by the first module (melt zone), functionalized thermoplastics already processed by the first module (melt zone with one or more coupling agents), or combinations thereof, for subsequent emulsification.

[0198] Dispersants may be added to promote the formation of stable dispersions or emulsions. In selected embodiments, the dispersant may be a surfactant, a polymer, or a mixture thereof. In some embodiments, the polymer may be a polar polymer having polar groups as comonomers or graft monomers. In preferred embodiments, the dispersant may comprise a stabilizer comprising one or more polar polyolefins having polar groups as comonomers or graft monomers.

[0199] The dispersant may comprise at least one carboxylic acid, a salt of at least one carboxylic acid, or a carboxylic acid ester or a salt of a carboxylic acid ester. The carboxylic acid, its salt, or the carboxylic acid moiety of a carboxylic acid ester, or a salt of such an ester, may have up to 60, 50, 40, 30, or 25 carbon atoms. The carboxylic acid, its salt, or the carboxylic acid moiety of a carboxylic acid ester, or a salt of such an ester, may have at least 12, at least 15, at least 20, or at least 25 carbon atoms. If in salt form, the dispersant comprises a cation selected from the group consisting of alkali metal cations, alkaline earth metal cations, or ammonium or alkylammonium cations. The dispersant may be an olefin (e.g., ethylene) carboxylic acid polymer, or a salt thereof, such as an ethylene-acrylic acid copolymer or an ethylene-methacrylic acid copolymer.

[0200] For example, the dispersant may include an ethylene / α-β-unsaturated carboxylic acid copolymer. In some embodiments, the ethylene / α-β-unsaturated carboxylic acid copolymer may include an ethylene-acid copolymer, such as an ethylene-acrylic acid copolymer or an ethylene-methacrylic acid copolymer. Typical copolymers include ethylene-acrylic acid (EAA) and ethylene-methacrylic acid copolymers, such as those marketed under the trademark PRIMACOR. TM (Trademark of The Dow Chemical Company), NUCREL TM (Trademarks of EI DuPont de Nemours) and ESCOR TM Those available (trademark of ExxonMobil). Other copolymers include ethylene ethyl acrylate (EEA) copolymers, ethylene methyl methacrylate (EMMA) and ethylene butyl acrylate (EBA). Other ethylene-carboxylic acid copolymers may also be used.

[0201] Alternatively, the dispersant may be selected from alkyl ether carboxylates, petroleum sulfonates, sulfonated polyoxyethylene alcohols, sulfated or phosphorylated polyoxyethylene alcohols, polymerized ethylene oxide / propylene oxide dispersants, primary and secondary alcohol ethoxylates, alkyl glycosides, and alkyl glycerides.

[0202] A combination of the above dispersants can be used.

[0203] In the case of certain dispersants or compatibilizers, it may be desirable to include a neutralizing agent to improve the effectiveness of the dispersant. For example, if the polar groups of the thermoplastic polymer are acidic or basic in nature, the dispersant may be partially or completely neutralized by a neutralizing agent to form the corresponding salt. In some embodiments, the neutralization of the dispersant (such as a long-chain fatty acid or EAA) may be based on a molar ratio of 25% to 200%; in other embodiments, it may be based on a molar ratio of 50% to 110%. For example, for EAA, the neutralizing agent is a base, such as, for example, ammonium hydroxide or potassium hydroxide. Other neutralizing agents may include, for example, lithium hydroxide or sodium hydroxide. Those skilled in the art will understand that the selection of a suitable neutralizing agent depends on the specific composition being formulated, and such selection is within the knowledge of those skilled in the art.

[0204] This document describes a method for forming a polymer-aqueous dispersion, optionally an emulsion, containing plastic. The dispersion can be formed in one or more extruders, such as a single-screw or twin-screw extruder (TSE). The single-screw or twin-screw extruder comprises a housing having an inlet end and an outlet end, and one or two rotating screws within the housing between the inlet end and the outlet end. Thermoplastic is introduced into the inlet end of the one or more single-screw or twin-screw extruders. The one or more single-screw or twin-screw extruders cause the thermoplastic to melt extensively to define a melt zone. In one example, at least a portion of the thermoplastic is reacted with a coupling agent selected from at least one of graft compatibilizers, active hydrogen donors, and functionalizing agents to define a functionalized thermoplastic. In another example, the thermoplastic (optionally functionalized) undergoes treatments including heat treatment and / or catalyst treatment to increase the molecular weight fraction (MFI).

[0205] Particle size reduction in an extruder is achieved via capillary breakup. In the melt zone, molten polymer is present. Following the melt zone may be a molten polymer seal. After the seal, water and optionally a surfactant are present, which undergo high-shear mixing to obtain striata—small fibers—which are metastable particles. The energy required to achieve particle size reduction using these methods is significantly lower than that of standard size reduction techniques.

[0206] In some embodiments, at least 10% by weight of the thermoplastic may be functionalized. The remaining portion of the thermoplastic (90% or less by weight of the thermoplastic) may be unfunctionalized. Other proportions of functionalized and unfunctionalized materials may be used. The degree of functionalization of the functionalized thermoplastic portion may vary depending on the reaction conditions and reactant availability. In some embodiments, as previously discussed, the degree of functionalization of the thermoplastic polymer in a portion of the functionalized thermoplastic may be between 0.5% and 6%.

[0207] A twin-screw extruder (TSE) consists of two screws mounted in a barrel with a "figure-eight" cross-section. The "figure-eight" cross-section is derived from the machining of two cylindrical bores whose centers are less than two radii apart. Twin-screw extruders typically use segmented screws, which are assembled on a high-torque splined shaft or have a solid screw machined from round bar stock. The TSE barrel can be modular. Liquid cooling can also be used in TSEs. The TSE motor inputs energy into the process via the rotating screws. A feeder meteres material into the TSE. The screw rpm can be independent of other processing conditions and can therefore be set to optimize processing efficiency. The combination of segmented screws and barrel with the controlled pumping and wiping characteristics of co-rotating screws allows the screw / barrel geometry to be matched to the process task.

[0208] The TSE or other extruder can be modular, wherein the first module contains at least the melt zone of the TSE or other extruder and the second module contains at least the emulsification zone of the TSE or other extruder.

[0209] In the case of a single non-modular twin-screw extruder, such as Figure 5E As shown, the thermoplastic 7 travels directly from inlet 3 to outlet 4, passing through each of the various zones of the TSE, such as melt zone 5 and emulsification zone 6. Similar zones and operating modes are also found in other extruders that may replace the twin-screw extruder mentioned herein. In one example, all the extruded thermoplastic is subjected to a functionalization reaction to compatibilize the thermoplastic. Those skilled in the art will understand that this does not mean that all thermoplastic polymer groups are actually functionalized. Typically, only a small fraction of the groups will be functionalized, for example, between 0.5% and 6%. There are various reasons for the lack of functionalization of all polymer functional groups, including—functional groups being blocked by other chemical moieties, incomplete melting, mixing, or granulation of the thermoplastic. In cases where the thermoplastic is being processed, optionally in addition to functionalization, the thermoplastic may be processed in melt zone 5.

[0210] In some cases, it may be desirable to provide emulsions comprising a mixture of granulated functionalized thermoplastics and granulated nonfunctionalized thermoplastics. In some cases, granulation can be achieved within the extruder and does not require prior pre-processing. This can be achieved by batch processing of thermoplastics via a single modular or non-modular extruder, wherein one batch 8 includes the addition of one or more coupling agents and / or crosslinking agents, and a second batch 9 does not include the addition of coupling agents or crosslinking agents. The two resulting thermoplastic dispersions or emulsions can then be subsequently mixed to form a combined thermoplastic dispersion or emulsion having the desired mixture of functionalized and nonfunctionalized granulated thermoplastics. Alternatively, as... Figure 5FAs shown, the functionalized thermoplastic 8 and the unfunctionalized thermoplastic 9 can be processed through a single melt zone 5 and then run through the extruder / TSE emulsification zone 6 to produce an emulsion.

[0211] Alternatively, a combination of extruder / TSE modules, or either the extruder or the TSE, can be used. For example, such as Figure 5G As shown, the method may include multiple first modules (51 and 52) containing melt zones. The thermoplastic in one melt zone module 51 may be reacted with one or more coupling agents, while the thermoplastic in the second melt zone module 52 may not be reacted with coupling agents. The resulting molten thermoplastic from both modules may be fed into a second module 6 (i.e., the emulsification module) to provide a resulting thermoplastic dispersion or emulsion of a mixture of functionalized and unfunctionalized thermoplastics.

[0212] Alternatively, such as Figure 5H As shown, thermoplastic 7 can be fed into an extruder / TSE module having a melt zone 5 and reacted with one or more coupling agents to produce molten functionalized thermoplastic 8. The molten functionalized thermoplastic 8 can then be fed together with non-molten, non-functionalized thermoplastic 1 into a second module containing an emulsification zone 6.

[0213] Functionalized molten thermoplastics can be emulsified in the emulsification zone of a twin-screw extruder by exposing the functionalized molten thermoplastics to water, a surfactant, and shear forces sufficient to form functionalized thermoplastics with an average particle size (Dv50) of less than 0.5 mm, to produce a functionalized thermoplastic dispersion or emulsion having water as the continuous phase. The functionalized thermoplastic dispersion or emulsion is then extruded through the outlet end of one or more of the twin-screw extruders, the emulsion containing functionalized plastic particles with an average particle size (Dv50) of less than 0.5 mm.

[0214] Example 13 provides an example relating to the preparation of wood fiberboard from a variety of recycled thermoplastic raw materials.

[0215] The method may further include adding a crosslinking agent in liquid form and optionally additional water to the functionalized thermoplastic emulsion within one or more extruders or twin-screw extruders at a temperature insufficient to chemically activate the crosslinking agent.

[0216] Thermoplastic dispersions / emulsions derived from emulsification / TSE processes can be used as binders. The binder can then be mixed with lignocellulosic material fibers to form a composite mixture and added to a press that applies heat and pressure to the composite mixture to form a lignocellulosic-thermoplastic composite.

[0217] The extruder or twin-screw extruder can be modular. That is, a first module may contain the melt zone of the twin-screw extruder, which may include the addition of coupling agents and optionally the treatment with heat or a catalyst, and a second module may contain the emulsification zone of the extruder or twin-screw extruder, which at least includes the addition of water and surfactants and optionally the treatment with a catalyst.

[0218] exist Figures 5O to 5S In the examples shown, the extruder includes zones adapted for specific processing steps. The extruder or TSE is configured with different zones for processing thermoplastics. In one example, thermoplastic feeding and melting occur in a first section of the extruder or TSE (referred to as the "melt zone"). The melt zone may also include zones for functionalizing, heat-treating, or catalyzing the thermoplastic (which occurs downstream of where the thermoplastic melts). Zones for functionalization or catalysis may include the addition of one or more coupling agents to functionalize the thermoplastic, such that the coupling agent functionalizes the thermoplastic after it has melted. The coupling agent and / or catalyst may be combined with the thermoplastic before it is fed into the extruder or TSE, or the coupling agent and / or catalyst may be added to the extruder or TSE via an injection port during or after the thermoplastic melts in the melt zone.

[0219] Figures 5O to 5S An example of thermoplastic 7 being processed in an extruder is shown. Figure 5O In this process, thermoplastic 7 is fed into the extruder via feeder 3 and travels through melt zone 5 to provide molten thermoplastic. The molten thermoplastic proceeds to functionalization or treatment zone 5A, where it is mixed with a coupling agent or catalyst, which may be injected at inlet 5Ai or added simultaneously or sequentially with the thermoplastic 7 via feeder 3. In one example, functionalization or treatment zone 5A is controlled to provide an optimal temperature for functionalization or thermal / catalytic treatment of the thermoplastic. In another example, functionalization or treatment zone 5A is adapted to be heated to a treatment activation temperature to achieve an increase in MFI as described herein. For example, heat treatment can achieve an activation temperature significantly higher than the melt temperature of the thermoplastic or a mixture of thermoplastics. The thermoplastic then enters mixing zone 5B, where it is mixed before extrusion through outlet 4 to provide functionalized and / or treated thermoplastic. Functionalized or treated thermoplastics can be emulsified using a separate extruder to provide thermoplastic dispersions.

[0220] exist Figure 5PIn another example shown, the mixing zone 7a may be replaced by or combined with the emulsifying zone 6. In this example, water, optionally a surfactant, and optionally a catalyst are injected at the injection port 6Ai and mixed throughout the emulsifying zone to provide a thermoplastic dispersion extruded through the outlet 4.

[0221] exist Figure 5Q In another example shown, the thermoplastic travels through melt zone 5 to emulsification zone 6, which may include the processing of the thermoplastic. In this example, water, optionally a catalyst, and optionally a surfactant are injected at inlet 6Ai and mixed throughout the emulsification zone to provide a thermoplastic dispersion extruded through outlet 4.

[0222] exist Figure 5R In another example shown, the thermoplastic travels through melt zone 5 to mixing zone 5B (where it is optionally mixed with a catalyst), which may include the processing of the thermoplastic. In this example, water, optionally a catalyst, and optionally a surfactant are injected at inlet 6Ai and mixed throughout emulsification zone 6 to provide a thermoplastic dispersion extruded through outlet 4.

[0223] In one instance, the extrusion process described in 5R occurs... Figure 5O Following the process described in [the document / article].

[0224] An extruder can contain multiple mixing zones, heat treatment zones, and injection zones.

[0225] exist Figure 5S In another example shown, thermoplastic 7 is fed into the extruder via feeder 3 and travels through melt zone 5 to provide molten thermoplastic. The molten thermoplastic proceeds to functionalization / treatment zone 5A, where it is mixed with at least one of a coupling agent and a catalyst, which may be injected at inlet 5Ai or added simultaneously or sequentially with the thermoplastic 7 via feeder 3. In one example, functionalization / treatment zone 5A is controlled to provide an optimal temperature for the functionalization and / or treatment of the thermoplastic. The thermoplastic then enters mixing zone 5B, where it is mixed before proceeding to emulsification zone 6. Water and optionally a surfactant are injected at inlet 6Ai and mixed throughout the emulsification zone to provide a functionalized and / or treated thermoplastic dispersion. The dispersion may be subjected to an additional mixing zone (not shown) or conveying zone (not shown) before being extruded through outlet 4.

[0226] In one example, the apparatus comprises a sequential combination of a melt zone, a mixing / processing zone, and an emulsification zone. This example provides particularly efficient size reduction and dispersion preparation. This is believed to be due to the syringe port 6Ai being located after the mixing zone. In one example, the syringe port 6Ai serves to lower the temperature by adding liquids (i.e., water and surfactants) at a significantly lower temperature than the molten material.

[0227] The extruder temperature configuration can be determined based on reaction requirements. The melt zone is defined as requiring a temperature setpoint higher than the melt temperature at which the thermoplastic is being processed. Temperatures for LDPE can be above 130°C, and for PP, temperatures can be above 160°C–220°C. The mixing zone comprises temperatures approximately the same as the melt temperature to maintain the thermoplastic in a molten state. An optional venting zone is defined after the mixing zone to allow unreacted monomers to evaporate and to purify the thermoplastic output. The temperature in the venting zone is set to allow coupling agents to volatilize and can be up to 20°C hotter than the melt zone, for example, above 200°C. The temperature can be lowered before exiting the extruder to reduce the viscosity of the extruded material.

[0228] In one instance, the thermoplastic undergoes a treatment that includes heat treatment. This involves heating the thermoplastic to an “activation temperature” significantly above its melt temperature. As shown in Examples 2A and 2B, this heat treatment has been demonstrated to significantly increase the melt flow index and improve sheet properties compared to thermoplastics processed at lower temperatures. Further discussion of activation temperatures is provided below.

[0229] The definitions of the zones described above will be clear to those skilled in the art. However, for example, the melt zone encompasses the zone of an extruder with a temperature setpoint that achieves substantially complete melting of the polymer feedstock. The melt zone can be defined by an aggressive melt zone design, for example, by using neutral / wide kneading block elements. The melt zone can also use a reverse element. A reverse element can achieve complete melting of the thermoplastic polymer. Alternatively, the melt zone can be defined by an extended screw design using narrow-disc kneading block elements. Narrow-disc kneading block elements can result in a lower intensity shear stress input into the thermoplastic polymer, leading to a more gradual melting of the polymer.

[0230] As the components are delivered along the length of the screw, extruder screw elements are selected for different unit operations. In one example, the sequence is first the melting zone, then the mixing and conveying zone, followed by the emulsification zone, and finally the dilution and cooling zone. Vapor pressure at the feed end is controlled by placing kneading blocks and bubble cap elements between the melt mixing zones and by using a back pressure regulator. Polyolefins, dispersants, compatibilizers, and water are melt-kneaded in the extruder.

[0231] The melt zone can be heated to approximately 140°C to approximately 240°C, or as needed, until the thermoplastic melts in the melt zone. For some low-melting-point thermoplastics, the melt zone can be set to 95°C to 140°C. During startup, the extruder temperature is increased to a higher set point compared to the operating temperature. In one example, the startup temperature is increased to at least approximately 150°C. In another example, where the thermoplastic melt temperature is even higher, the temperature is increased to approximately 180°C.

[0232] The melt zone can be heated using external heating elements. It should be understood that when the extruder or TSE is started, it will include heat inputs (such as heating elements or heating jackets). However, once the extruder or TSE has been running for a sufficient period, it will generate heat via frictional heating. As frictional heat increases, the external heat input can be reduced (or possibly removed) to prevent overheating. Overheating can lead to degradation of thermoplastics, as indicated by smoke and discoloration. The extruder or TSE may include cooling elements in the melt zone to prevent overheating. Cooling elements can take the form of cooling channels. Cooling liquids (such as water) can flow through the cooling channels to cool the extruder or TSE. During operation, the extruder or twin-screw extruder is maintained at setpoint temperatures along the barrel in these zones. In one example, the barrel contains one or more water-cooled zones.

[0233] The temperature setpoint of the cylinder can be automatically adjusted to maintain it at or near the cylinder temperature setpoint. This automatic feedback mechanism is implemented using a temperature regulating device. In this device, a temperature sensor located in or near the cylinder senses the temperature and then feeds the data to a temperature controller. Based on the cylinder temperature setpoint, the controller adjusts the temperature using components of the temperature regulating device. The temperature can be regulated by a water cooling device adapted to the cooling cylinder. The temperature can also be regulated by a heating element adapted to the heating cylinder.

[0234] Multiple extruder zones may exist, each containing a temperature control device. These examples discuss experiments using waste polymers. These experiments demonstrate that, to achieve more effective emulsification of the waste polymers, the extruder temperature setpoint can be set above the melt temperature of the polymer being processed, for example, by 20%.

[0235] In other experiments, the inventors have found that applying an average barrel temperature significantly higher than the melting point of the polymer has a beneficial effect on MFI and plate properties. Examples 2A and 2B demonstrate this unexpected effect when a significantly higher temperature (referred to herein as the “activation temperature”) is reached, and Figure 2A(i) shows an unexpected increase in MFI.

[0236] Therefore, in one instance, the melt zone temperature can be the activation temperature as previously described. The melt zone temperature can be calculated by taking the average temperature across the entire melt zone. The melt zone may contain no or substantially no water. The melt zone may contain less than 5%, 4%, 3%, 2%, or 1% water by weight of the thermoplastic, and suitable ranges may be selected from any of these values.

[0237] Once processed through the melt zone, thermoplastics can be processed by different sections of an extruder or TSE. In one example, the next zone contains a mixing zone. The mixing zone may contain kneading and mixing elements. Processes including heat treatment and catalyst treatment can be performed before, during, or after mixing in the mixing zone.

[0238] The examples provided herein may also include emulsification or dispersion zones, which include the addition of water and optionally a surfactant.

[0239] Once in the emulsification zone of the extruder or TSE, water and optionally a surfactant are added to the thermoplastic, which can also be functionalized. When water and surfactant are added, the thermoplastic can form a bicontinuous phase in the first section of the emulsification zone. The bicontinuous phase is an intermediate phase between oil-in-water and water-in-oil mixtures. The bicontinuous phase can also be an intermediate phase between polymer-in-water and water-in-polymer mixtures. When additional water is added to the emulsification zone, the emulsion forms with water as the continuous phase.

[0240] An emulsion is formed while being subjected to shear forces in the emulsification zone of an extruder or TSE. The shear forces are provided by the design of the extruder, such as one or more screws in the emulsification zone of the extruder or TSE that impart shear forces (or shear stress).

[0241] The emulsification zone may include a water mixing zone, where water and surfactant are initially mixed, and a shear zone downstream of the water mixing zone to impart shear force. In one example, the water (and optionally surfactant) mixing zone and the shear zone are combined to define a dispersion zone. The dispersion zone appears before the dilution zone.

[0242] The emulsification zone may include a dilution zone containing an inlet for adding additional water. That is, an initial amount of water is optionally added along with the surfactant before the mixing zone. Additional water is injected at the dilution zone as the material moves downstream of the water mixing zone. This additional water can be introduced where the bicontinuous phase transitions to an oil-in-water or polymer-in-water phase (with water as the continuous phase).

[0243] The surfactant can be blended with the feed mixture before it enters the extruder, which is particularly effective when using solid surfactants such as PVOH. Alternatively, the surfactant can be injected into the extruder downstream of the feed, and preferably downstream of the melt zone.

[0244] Water can be supplied through a water inlet, for example, see [link to example]. Figures 50 to 5S And optionally, additional inlet ports. That is, the water injection line terminating at the inlet port may include a flow meter and valve to control the amount of water added to the extruder or TSE.

[0245] The water flow rate allows for the determination of a specific moisture content in the resulting thermoplastic dispersion. Given that this amount is scale-dependent, it is typically described as a resin:water ratio w / v. In the methods described herein, the resin comprises a thermoplastic. In some embodiments, the resin:water ratio is in the range of 1:1 to 5:1. The resin:water ratio after the mixing zone can be a ratio of 2:1 to 5:1. This provides water but maintains a high resin loading during the particle decomposition phase. The water input into the dilution zone can be adjusted to achieve a resin:water ratio between approximately 0.8:1 and 1.8:1 in the dilution zone. The increased amount of water added to the dilution zone, optionally in combination with a surfactant, results in the dispersion of particles to form a thermoplastic dispersion.

[0246] The resin:water ratio can be adjusted to achieve the target moisture content of the thermoplastic dispersion. Moisture content is a critical parameter in the production of composite boards, such as those made from lignocellulosic materials, because too much moisture results in a weak board. Similarly, too little moisture can impair the ability of certain crosslinking agents to effectively bond with the lignocellulosic material.

[0247] Thermoplastic dispersions can contain a moisture content between 25% and 75%. This moisture content can be tailored to ensure that the moisture content of the sheets prepared using the thermoplastic dispersion is within a preferred range. Therefore, the moisture content of the thermoplastic dispersion is preferably in the range of 35% to 55%. The moisture content of the dispersion can be adjusted, for example, by dilution in the dilution zone of an extruder. Alternatively, it can be further adjusted by drying after extrusion. Achieving a specific preferred moisture content reduces the drying requirements of the dispersion, which has considerable benefits in terms of reducing energy consumption and preparation time. In this example, the moisture content of the thermoplastic dispersion is between about 40% and 50%.

[0248] The water injection system can be a high-pressure, low-volume system. For example, the system may include an injector, which may be based on a spring-loaded ball, manifold, and pump installed in the inlet chamber of the extruder. The manifold may include a gate valve, a needle valve for regulation, and a flow meter.

[0249] The inventors have discovered that the properties of the thermoplastic dispersion obtained after emulsification can affect the properties of materials made with adhesives containing the thermoplastic dispersion. In particular, the properties affected include variations in particle size, particle size distribution, and melt flow index.

[0250] Furthermore, the properties of the thermoplastic introduced into the extruder also affect the properties of the resulting thermoplastic dispersion after emulsification. The inventors have discovered that using thermoplastics with higher melt flow indices provides thermoplastic dispersions with lower particle sizes. Smaller particle sizes facilitate mixing with lignocellulosic materials to form composite panels. Additionally, smaller particle sizes provide enhanced bonding between the binder and the lignocellulosic material.

[0251] A method is described for processing thermoplastics to increase their melt flow index, followed by steps to prepare thermoplastic dispersions and optionally produce sheets. The preparation of the dispersions and sheets is carried out according to the method described herein. Thermoplastic dispersions with higher melt flow indices can be associated with reduced particle size and reduced particle size distribution.

[0252] As discussed herein, the inventors have discovered specific methods for achieving unexpectedly high MFI by applying certain treatment steps during the processing of thermoplastics. For example, heat treatment at activation temperature and catalyst treatment have been identified as methods for unexpectedly achieving this effect for both unprocessed and waste plastics. This effect is particularly important for waste plastics because they typically have lower MFI and higher branching than unprocessed polymers intended to melt and form.

[0253] A crosslinking agent is added before manufacturing the composite board. The crosslinking agent can be added to the extruder / TSE or the extruded thermoplastic dispersion / emulsion, or both the extruder / TSE and the extruded emulsion.

[0254] The crosslinking agent can be selected from participating crosslinking agents or non-participating crosslinking agents. A participating crosslinking agent is a crosslinking agent that directly participates in the bonding between the two compounds being linked. That is, one end of the participating crosslinking agent forms a bond with one of these compounds and the other end forms a bond with the other compound.

[0255] Non-participatory crosslinking agents are crosslinking agents that do not directly participate in the bonding between the two compounds. That is, they do not form bonds with the two compounds to be bonded. Instead, the non-participatory crosslinking agent interacts with one or more of these compounds to provide an active site on at least one of these compounds. This active site then provides a site for bonding between the two compounds.

[0256] The temperature of the extruder or TSE can be altered before or during the addition of the participating crosslinking agent. The extruder / TSE temperature can be reduced using a water-based cooling system (such as a high-pressure water cooling system, barrel cooling, or water jacket). The extruder / TSE temperature can also be reduced by adding water. A combination of water addition and an active cooling system can be used to reduce the temperature.

[0257] The cross-linking agent can be isocyanate. However, without being limited by theory, the addition of isocyanate can also reduce the hydrophilicity of lignocellulose fibers / materials.

[0258] The temperature of the extruder / TSE can be altered before or during the addition of a non-participating crosslinking agent. The temperature of the extruder / TSE can be reduced using a water-based cooling system (such as a high-pressure water cooling system, barrel cooling, or water jacket). The temperature of the extruder / TSE can be reduced by adding water. The temperature of the extruder / TSE can be reduced using a combination of water addition and an active cooling system.

[0259] Non-participatory cross-linking agents can be organic peroxides.

[0260] If a non-participating crosslinking agent such as an organic peroxide is added, it can be added at approximately 0.1%, 0.5%, 1%, 2%, 3%, 4%, or 5% by weight of the thermoplastic dispersion / emulsion, and a suitable range can be selected from any of these values. A non-participating crosslinking agent such as an organic peroxide can be added when a graft compatibilizer or an active hydrogen donor has already been added.

[0261] The inventors have prepared wood fiber composite boards using organic peroxide crosslinking agents. Specifically, 1,1-di-(tert-butylperoxide)-3,3,5-trimethylcyclohexane enhances the strength of wood fiber composite boards prepared from a thermoplastic dispersion of LDPE in water. Organic peroxide crosslinking agents can be added to the thermoplastic dispersion to form a binder containing between 1% and 10% organic peroxide to provide enhanced strength. In some embodiments where lower strength is acceptable, the organic peroxide crosslinking agent is added between 2% and 8%.

[0262] As described, the adhesive may contain the following: Organic peroxides (e.g., Luprox) 3%-5% MAPE 10%-20% Thermoplastic dispersions 75%-87%

[0263] As described, the composite plate of the present invention may comprise the following components (w / w): 95% lignocellulosic material (e.g., wood fiber); 4% thermoplastic dispersion 0.75% MAPE 0.25% organic peroxide (e.g., luprox)

[0264] Organic peroxides can be provided in powder or liquid form. Experiments conducted by the inventors have shown that the powder form makes mixing easier. Powdered organic peroxides can contain 40% benzoyl peroxide.

[0265] If a crosslinking agent such as isocyanate is added, it can be added at about 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% by weight of the thermoplastic dispersion / emulsion, and suitable ranges can be selected from any of these values ​​(e.g., about 0.1% to about 15%, about 0.1% to about 13%, about 0.1% to about 10%, about 0.1% to about 8% by weight of the thermoplastic dispersion / emulsion). Approximately 0.1% to approximately 5%, approximately 0.5% to approximately 20%, approximately 0.5% to approximately 19%, approximately 0.5% to approximately 17%, approximately 0.5% to approximately 12%, approximately 0.5% to approximately 9%, approximately 0.5% to approximately 5%, approximately 1% to approximately 20%, approximately 1% to approximately 18%, approximately 1% to approximately 16%, approximately 1% to approximately 14%, approximately 1% to approximately 10%, approximately 2% to approximately 20%, approximately 2% to approximately 18%, approximately 2% to approximately 16%, approximately 2% to approximately 14%, approximately 2% to approximately 10%, approximately 3% to approximately 20%, approximately 3% to approximately 17%, approximately 3 % to about 15%, about 3% to about 11%, about 3% to about 9%, about 4% to about 20%, about 4% to about 18%, about 4% to about 16%, about 4% to about 10%, about 5% to about 20%, about 5% to about 18%, about 5% to about 17%, about 5% to about 11%, about 6% to about 20%, about 6% to about 18%, about 6% to about 16%, about 6% to about 12%, about 6% to about 10%, about 7% to about 20%, about 7% to about 18%, about 7% to about 15%, about 7% to about 12%, about 7% to about 10% %, about 8% to about 20%, about 8% to about 17%, about 8% to about 15%, about 8% to about 13%, about 8% to about 10%, about 9% to about 20%, about 9% to about 16%, about 9% to about 13%, about 10% to about 20%, about 10% to about 16%, about 11% to about 20%, about 11% to about 17%, about 12% to about 20%, about 12% to about 17%, about 13% to about 20%, about 13% to about 18%, about 14% to about 20%, about 14% to about 18%, or about 15% to about 20%. When an active hydrogen donor has already been added as a coupling agent, a participating crosslinking agent, such as isocyanate, may be added.

[0266] The inventors have determined a preferred stoichiometric ratio of isocyanate to thermoplastic dispersion, which achieves efficient reaction kinetics and composite board strength. Therefore, the adhesive can contain between 5% and 50% isocyanate. In other words, the isocyanate is added at 5% to 50% by weight of the adhesive. In some instances, the adhesive properties of the crosslinking agent synergize more effectively with the treated thermoplastic, and in these cases, the crosslinking agent can be contained between 5% and 20%, wherein the crosslinking agent can be an isocyanate. In one specific example, the composite board can contain the following composition (w / w): 90% lignocellulosic materials (e.g., wood fiber); 9% thermoplastic dispersion; 1% eMDI.

[0267] Alternative composite panel compositions may include: 90% lignocellulose material; 8% thermoplastic dispersion; 2% eMDI.

[0268] Alternative composite panel compositions may include: 90% lignocellulose material; 9.5% thermoplastic dispersion; 0.5% eMDI.

[0269] Alternative composite panel compositions may include: 87% lignocellulose material; 10% thermoplastic dispersion; 3% eMDI.

[0270] Examples 2B and 12 provide various further examples of the composite board compositions as described. Particleboards containing thermoplastic binders prepared according to the method described in Example 2B at 1%, 2%, and 3% pMDI loadings exhibited unexpectedly good performance characteristics. This example demonstrates that high-grade wood fiberboard produced using high-temperature processed LDPE waste thermoplastics outperforms boards produced without thermoplastic binders at all pMDI loadings. Therefore, compared to the control, activated waste thermoplastics impart the quality of improved composite board performance to the adhesive.

[0271] To avoid being limited by theory, it is believed that the reaction of isocyanates with natural fibers alters their polarity. An urethane link forms between the isocyanate functional group and the hydroxyl groups of the natural fiber, which blocks the hydrophilic hydroxyl sites, resulting in less hydrophilicity of the wood fiber and therefore greater compatibility with hydrophobic thermoplastics. As described, the use of diisocyanates can form bonds with the reactive moieties of functionalized and / or treated polymers. One isocyanate group of the diisocyanate can react with the hydroxyl groups on the wood fiber, and another isocyanate group reacts with the reactive moieties on the functionalized and / or treated polymer. This can form a covalent bond between the reactive moieties on the functionalized and / or treated polymer and the diisocyanate.

[0272] Isocyanates can also react with other hydroxyl groups on lignocellulose fibers, such as wood fibers, which may mask their hydrophobicity. In this way, diisocyanates can be used to block polar hydrophobic hydroxyl groups on fibers or to form covalent bonds with reactive moieties on functionalized and / or treated polymers, which can increase the compatibility of plastic polymers and wood fibers.

[0273] Emulsified isocyanate compounds, such as emulsified methylene diphenyl diisocyanate (eMDI), can be used as crosslinking agents in combination with thermoplastic dispersions to produce composite panels. Example 12 shows that when isocyanates are combined with thermoplastic dispersions (e.g., thermoplastic dispersions prepared according to the methods described herein), eMDI achieves better mixing properties and enhanced strength compared to pMDI.

[0274] Thermoplastic dispersions can be formulated into adhesives by combining the dispersions with one or more crosslinking agents as described in detail above. To form a composite board, the adhesive is then combined with a lignocellulosic material. The adhesive can comprise between 1% and 50% of the composite mixture. However, providing more than 20% adhesive within the board may impair its properties due to the reduced fiber content (which provides the physical matrix for enhanced strength).

[0275] Therefore, the adhesive formulation may constitute 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the composite panel by weight, and suitable ranges may be selected from any of these values ​​(e.g., about 1% to about 20%, about 1% to about 18%, about 1% to about 16%, about 1% to about 14%, about 1% to about 10%, about 2% to about 20%, about 2% to about 18%, about 2% to about 16%, about 2% to about 14%, about 2% to about 10%, about 3% to about 20%, about 3% to about 17%, about 3% to about 15%, about 3% to about 11%, about 3% to about 9%, about 4% to about 20%, about 4% to about 18%, about 4% to about 16%, about 4% to about 10%, about 5% to about 20%) by weight of the composite panel, and suitable ranges may be selected from any of these values ​​(e.g., about 1% to about 20%, about 1% to about 18%, about 4% to about 16%, about 4% to about 10%, about 5% to about 20%) by weight of the composite panel. %, about 5% to about 18%, about 5% to about 17%, about 5% to about 11%, about 6% to about 20%, about 6% to about 18%, about 6% to about 16%, about 6% to about 12%, about 6% to about 10%, about 7% to about 20%, about 7% to about 18%, about 7% to about 15%, about 7% to about 12%, about 7% to about 10%, about 8% to about 20%, about 8% to about 17%, about 8% to about 15%, about 8% to about 13%, about 8% to about 10%, about 9% to about 20%, about 9% to about 16%, about 9% to about 13%, about 10% to about 20%, about 10% to about 16%, about 11% to about 20%, about 11% to about 17%, about 12% to about 20%, about 12% to about 17%, about 13% to about 20%, about 13% to about 18%, about 14% to about 20%, about 14% to about 18% or about 15% to about 20%. If the formulation contains too little binder, the coating of the lignocellulose particles is insufficient to create effective bonds between the particles. This results in a board that separates under load. Therefore, the lignocellulose material:binder ratio can range from approximately 80% lignocellulose material: 20% binder to 95% lignocellulose material to 5% binder. In other examples, the lignocellulose material:binder ratio can range from approximately 85% lignocellulose material: 15% binder to 92% lignocellulose material to 8% binder.

[0276] Example 12 shows that composite boards with lower lignocellulosic material content experience less swelling and are therefore more suitable for outdoor or humid environments. Therefore, for boards exhibiting less than 20% swelling after 24 hours, the lignocellulosic material:binder ratio ranges from approximately 90:10 to 85:15.

[0277] Composite panels can be designed to meet certain minimum strength standards. Examples 2B and 12 provide exemplary adhesive compositions comprising different levels of crosslinking agent, thermoplastic dispersion, and lignocellulosic material. The composite panel prepared using a thermoplastic dispersion prepared according to the methods described herein has a modulus of elasticity of at least 1000 MPa when measured according to ASTM D1037 or EN310. This provides a panel suitable for lightweight applications. In alternative examples where stronger panels are required, the composite panel may have a MoE greater than 1200, 1400, or 1600, depending on the end-use requirements. Example 2B provides an example of a composite panel that meets these strength requirements with different levels of crosslinking agent. In this example, the adhesive comprises between 70% and 95% thermoplastic dispersion and between 5% and 30% crosslinking agent. In another example, the adhesive comprises between 85% and 94% thermoplastic dispersion and between 6% and 15% crosslinking agent. In the case of preparing composite panels according to the methods described herein, the adhesive may comprise between about 5% and 20% of the composite material mixture used to prepare the composite panel, with the remainder consisting of lignocellulosic materials. In alternative examples, the adhesive comprises between about 8% and 15% of the composite material mixture, with the remainder consisting of lignocellulosic materials, such as sawdust.

[0278] Combining adhesives with fibers such as lignocellulose materials can be achieved in a variety of ways, including mixing with a paddle mixer, mixing by tumbling, and / or spraying the adhesive while mixing. The preparation of thermoplastic dispersions as described herein offers enhanced mixing and resulting board properties compared to simply mixing dimensionally reduced thermoplastics with crosslinking agents and lignocellulose substrates.

[0279] In one instance, the crosslinking agent can be added in powder form or, alternatively, in solid form. The crosslinking agent is typically added in small amounts to the extruder / TSE, and therefore can also be added to the TSE in liquid form (i.e., dissolved in water).

[0280] After adding the crosslinking agent, additional water can be added to the TSE.

[0281] When the crosslinking agent is a non-participating crosslinking agent such as an organic peroxide, the emulsion can be dried to a water content of less than about 3% by weight.

[0282] When the crosslinking agent is a participatory crosslinking agent such as isocyanate, drying may not be required. That is, isocyanates are more water-resistant than organic peroxide crosslinking agents. The increased presence of water can provide heat transfer benefits during the board fabrication process. Emulsions containing isocyanates can have a solids content of about 30%, 40%, 50%, 60%, or 70% by weight, and suitable ranges can be selected from any of these values. In some preferred embodiments, emulsions containing isocyanates can have a solids content of about 50%, 55%, 60%, 65%, or 70% by weight, and suitable ranges can be selected from any of these values. In some embodiments, additional water may be used. For example, additional water may be added immediately before board fabrication to dilute the emulsion. Adding water allows for controlled viscosity.

[0283] The adhesive mixture contains at least a thermoplastic dispersion and a crosslinking agent and can be used in the manufacture of plastic composite materials, such as panels or sheets. When the plastic composite material is mixed with fibers (such as lignocellulosic matrix / materials), the sheet can be selected from fiberboard, oriented strand board, waffle board, particleboard, flexible board, MDF, and / or rigid board.

[0284] In alternative examples, adhesive materials are used in the preparation of composite materials comprising fibers selected from the group consisting of: fiber-reinforced polymers (FRP), glass fiber-reinforced polymers (GFRP or glass fiber), carbon fiber-reinforced polymers (CFRP), aramid fiber-reinforced polymers (AFRP, such as Kevlar), particle-reinforced composites, polymer cement and concrete, metal matrix composites (MMC), laminated composites, plywood, laminated safety glass, adhesive-based composite joints, or laminates. In alternative embodiments, the adhesive can be used as an adhesive, whether or not it is combined with the fiber / matrix.

[0285] The composite panels described herein meet the needs of industries using recycled and waste plastic raw materials. Furthermore, these composite panels offer greater durability and water resistance. Specifically, bonds are formed through a substantially irreversible reaction using an isocyanate crosslinking agent incorporated into the thermoplastic polymer matrix. This results in a more durable and moisture-resistant bond, which is particularly advantageous in applications where exposure to humid or damp conditions is anticipated. The isocyanate-thermoplastic adhesive provides enhanced resistance to water and humidity, ensuring the lifespan and integrity of the bond in challenging environments.

[0286] Crosslinking agents can be added in powder form or, alternatively, in solid form. When added directly to the extruder / TSE, crosslinking agents are typically added in small amounts in liquid form (i.e., dissolved in water). Additional water can be added to the extruder / TSE after the crosslinking agent has been added.

[0287] When the crosslinking agent is a non-participating crosslinking agent such as an organic peroxide, the emulsion can be dried to a water content of less than about 3% by weight.

[0288] When the crosslinking agent is a participatory crosslinking agent such as isocyanate, drying may not be required. That is, isocyanates are more water-resistant than organic peroxide crosslinking agents. The increased presence of water can provide heat transfer benefits during the board fabrication process. Emulsions containing isocyanates can have a solids content of about 30%, 40%, 50%, 60%, or 70% by weight, and suitable ranges can be selected from any of these values. In some preferred embodiments, emulsions containing isocyanates can have a solids content of about 50%, 55%, 60%, 65%, or 70% by weight, and suitable ranges can be selected from any of these values. In some embodiments, additional water may be used. For example, additional water may be added immediately before board fabrication to dilute the emulsion. Adding water allows for controlled viscosity.

[0289] Achieving the target moisture content in adhesives and composite boards prepared according to the methods described herein can be important in determining bonding and strength. Crosslinking agents such as isocyanates and organic peroxides are highly reactive chemicals and can react with or be inhibited by the hydroxyl groups present in lignocellulose fibers. For example, isocyanate (-NCO) groups react with hydroxyl groups (-OH) to form urethane bonds (-NHCOO-). The moisture content in the wood fibers affects the availability of these OH groups. If the wood fibers are too dry, there may not be enough moisture to promote the reaction with isocyanates, resulting in poor adhesion and reduced board quality. Therefore, it is particularly important to match the moisture content of the board to the type of crosslinking agent used.

[0290] The moisture content of pre-compressed composite mixtures containing isocyanates can be greater than about 5%. This helps ensure that the isocyanates have sufficient binding capacity.

[0291] Example 13 describes the preparation of a composite mixture containing a moisture content between approximately 8% and 14%.

[0292] Furthermore, experimental verification has shown that the boards containing the composite mixture generated in the press should have a total pre-compression moisture content of less than about 15%. Preferably, the pre-compression moisture content is less than 12% or 13%. This minimizes the risk of problems such as excessive board expansion or warping during pressing and curing. Excessive vapor generated in the board can cause bubbles and may lead to failure. Therefore, the total pre-compression moisture content of the composite mixture can be between about 5% and about 15%.

[0293] A composite material mixture comprising an isocyanate crosslinking agent, a lignocellulose matrix, and a thermoplastic dispersion described herein is described, wherein the moisture content of the board is between 5% and 15%.

[0294] Unregulated lignocellulosic materials, such as sawdust, typically have a moisture content of 8%–12%. With this in mind, adhesives comprising crosslinking agents plus thermoplastic dispersions preferably contain less than 45% moisture.

[0295] The inventors have discovered that higher moisture content can impair bonding. Therefore, when the crosslinking agent contains organic peroxides, the total moisture content of the board can be less than 10%. When using a composite mixture with 10% adhesive and adhesive formulation with 5% organic peroxides, the moisture content of the thermoplastic dispersion is preferably reduced to less than 1% to achieve effective bonding.

[0296] Methods for producing thermoplastic composite sheets generally involve introducing a composite material mixture into a press or mold containing a binder and a fibrous or particulate lignocellulosic material. The composite material mixture may contain approximately 4% to approximately 30% binder by weight, with the remainder provided by the lignocellulosic material – a fibrous or particulate matrix. These examples provide several instances of different binder-to-composite material ratios.

[0297] Those skilled in the art will understand that a press or mold can include any device that applies heat and / or pressure to produce a flat or shaped solid product. Non-limiting examples of presses or molds can include 3-D molds, injection molds, compression molds, transfer molds, or rotary molds capable of producing complex 3D products.

[0298] In another instance, the thermoplastic dispersions or binders described herein can be used as resins in other applications, such as 3D printing.

[0299] The adhesive of this invention can be combined with fibers to produce composite panels. In one example, the fibers comprise lignocellulosic materials. The lignocellulosic material or fibrous or particulate matrix can comprise wood (such as sawdust, wood fiber, wood pellets, wood chips, or wood flakes), coconut shell, straw or rice husk, barley straw, or bamboo. The choice of lignocellulosic material or fibrous or particulate matrix will define the properties and uses of the composite product.

[0300] The examples provided in this article describe several instances of preparing composite panels using wood fibers. Furthermore, Example 11 describes the preparation of composite panels using a variety of other lignocellulosic materials.

[0301] For plywood and glued laminated timber products, the timber can be in sheet form, which is glued together using adhesives. In this case, the timber sheets can have at least one dimension with a length greater than about 1 m.

[0302] For other products, such as oriented strand board (OSB), waffle board, particleboard, softboard, MDF, or hardboard, the lignocellulose-based material / substrate may have at least one dimension (such as the major dimension) with a length less than 500 mm. For example, OSB may contain a lignocellulose-based material / substrate with a major dimension between about 50 mm and about 500 mm. Waffle board may contain a lignocellulose-based material / substrate with a major dimension between about 10 mm and about 50 mm. Particleboard may contain a lignocellulose-based material / substrate with a major dimension between about 1 mm and about 15 mm. Softboard, MDF, and hardboard may contain a lignocellulose-based material / substrate with a major dimension between about 1 mm and 5 mm.

[0303] Regarding lignocellulose-based materials / matrixes, the matrix can be derived from a range of different lignocellulose-based material products. For example, fine-grade lignocellulose-based materials / matrixes can have an average particle size of about 0.5, 1, 1.5, or 2 mm, and suitable ranges can be selected from any of these values ​​(e.g., about 0.5 to about 2, about 0.5 to about 1.5, about 0.5 to about 1, about 1 to about 2, about 1 to about 1.5, or about 1.5 to about 2 mm). For example, fine-grade lignocellulose-based materials / matrixes can be derived from sawdust or wood flour. It should be understood that, for use, any source producing lignocellulose-based materials / matrixes with an average particle size as defined above may be suitable. For example, grinding, such as using a hammer mill. The grinding system can control the size of the particles produced by using a grinding mill screen, which is a screen with a set perforation size.

[0304] The lignocellulose-based material / substrate can be a coarser grade of substrate having an average particle size of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 mm, and a suitable range can be selected from any of these values ​​(e.g., about 1 to about 15, about 1 to about 13, about 1 to about 10, about 1 to about 8, about 1 to about 5, about 2 to about 15, about 2 to about 14, about 2 to about 10, about 2 to about 6, about 3 to about 15, about 3 to about 12, about 3 to about 9, about 4 to about 15, about 4 to about 11, about 4 to about 8, about 5 to about 15, about 5 to about 13, about 5 to about 10, about 6 to about 15, about 6 to about 12, about 6 to about 10, about 6 to about 8, about 7 to about 15, about 7 to about 11, about 8 to about 15, about 8 to about 13, about 9 to about 15, about 9 to about 12 or about 10 to about 15 mm). For example, coarser grades of wood-based substrates can be derived from wood chips and wood pellets.

[0305] When defining the size of lignocellulose material particles as "average particle size," it should be understood that the size of lignocellulose material particles is not uniform. Considering that the shape of lignocellulose material particles is usually irregular, the average particle size refers to the length of the longest axis.

[0306] The conventional method for obtaining particle size distribution is mechanical sieving. The American Society of Agricultural and Biological Engineers (ASABE Standard S424.1, 2007) developed mechanical sieving as the standard particle size analysis method for biomass pellets. Mechanical sieving determines the percentage of particles by mass retained on each sieve. However, since particles pass through the sieve based on their width, particle length is ignored during the sieving process. Given that particles can be largely irregular and non-uniform in size and shape, two particles passing through the same sieve may have different shapes.

[0307] Unlike conventional mechanical sieving methods, advanced technologies such as machine vision can use image analysis techniques to analyze particle size and shape. Image analysis is a practical method for determining the actual size and shape of individual particles. Image analysis is not subjective and is repeatable on the same image.

[0308] Another way to characterize the size of lignocellulosic material particles is to observe the bulk density of the product. Smaller particles will allow them to rearrange themselves for more efficient packing conditions, resulting in a higher bulk density. For example, the bulk density of wood sawdust is approximately 370 kg / m³. 3 Approximately 415 kg / m 3 .

[0309] If a lignocellulosic material-composite product is desired, the substrate can include fine wood substrates and coarse wood substrates as mentioned above. The board is formed by first preparing a fine mixture and a coarse mixture. The fine mixture is prepared by mixing fine wood fibers with a binder containing a functionalized thermoplastic and a crosslinking agent. The coarse mixture is prepared by mixing coarse lignocellulosic material fibers with a binder containing a functionalized thermoplastic and a crosslinking agent.

[0310] When forming a sheet, the sheet can be formed by first layering a fine composite mixture in the bottom of a mold, then layering a coarse composite mixture, and then layering the fine composite mixture on top to clamp the coarse mixture. The prepared composite material is then pressed under pressure and temperature. In some embodiments, the ratio of the fine composite mixture to the coarse composite mixture is about 20:80 to 80:20. It should be understood that when preparing the fine composite mixture, it can be divided into top and bottom layers. Typically, the division ratio is from 40:60:60:40, and about 50:50 is preferred.

[0311] As mentioned above, the ratio of coarse composite mixture to fine composite mixture can be between 20:80 and 80:20, and ratios of 40:60 to 60:40 are also envisioned.

[0312] In a preferred embodiment, the plate is formed of 20% by weight of a fine composite material mixture, 60% by weight of a coarse composite material mixture, and then 20% by weight of a fine composite material mixture.

[0313] For composite products in plywood style, adhesive is applied between sheets by spraying or spreading the adhesive.

[0314] The composite material is formed into a mat in a press. The mat can be pre-compressed in a continuous press or subjected to separate stages in a non-continuous press to make the mat more compact before being placed in a hot press. The thickness of the composite material decreases under pressure, so that the final product cured before pressure and heat can be approximately 10%, 15%, 20%, 25%, 30%, or 35% of the thickness of the original composite mixture.

[0315] The pressure applied to the composite material mixture can be about 3, 4, 5, 6, 7, 8, 9 or 10 MPa, and a suitable range can be selected from any of these values ​​(e.g., about 3 to about 10, about 3 to about 9, about 3 to about 7, about 3 to about 6, about 3 to about 5, about 4 to about 10, about 4 to about 8, about 4 to about 6, about 5 to about 10, about 5 to about 8, about 5 to about 7, about 6 to about 10, about 6 to about 9 or about 7 to about 10 MPa).

[0316] The temperature of the press or mold heats the composite material to approximately 100°C to approximately 220°C. This is a temperature sufficient to melt the adhesive, allowing it to encapsulate and bond the substrate and form the product. In some embodiments, some thermoplastics within the adhesive may not melt, which may be a case where the adhesive contains thermoplastic contaminants. That is, while enough thermoplastics within the adhesive can melt to form a continuous phase encapsulating the substrate, some thermoplastics in the adhesive may remain unmelted and retained as particulate matter in the composite material.

[0317] Several factors can influence the hot pressing process, including pressing temperature, felt moisture content (MC), press closing speed, resin properties, and wood particle type. The rate of increase in press temperature significantly affects the adhesive curing rate. This not only affects the total pressing time but also plays a crucial role in creating a vertical density gradient within the material. Among these factors, felt moisture content significantly influences heat transfer within the felt. The rate at which heat penetrates the felt determines the required pressing time. Higher MC in the felt requires more energy for water vaporization.

[0318] It should be understood that the top and bottom fine mixture layers can be exposed to greater heating compared to the inner coarse mixture layer. Therefore, the functionalized thermoplastics used in the adhesive for the fine mixture can comprise functionalized thermoplastics with a higher melting point than those used in the adhesive for the coarse mixture (used in the middle layer of the board).

[0319] Each layer can comprise 5%, 10%, or 15% of the total thickness of the felt, and a suitable range can be selected from any of these values.

[0320] Thermoplastics can be mixtures of low-density or high-density PE and PP. Functionalized thermoplastics may contain a small percentage of contaminant thermoplastics, subjecting the composite mixture to pressure sufficient to reduce the thickness of the composite mixture, and subsequently heating the composite mixture to approximately 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, or 220°C to form a wood composite panel, and suitable ranges may be selected from any of these values.

[0321] A release agent can be applied to the surface of the press to prevent the composite material from adhering to the press platen. In some embodiments, the outer layer of the composite material may include urea-formaldehyde to inhibit the composite material from adhering to the press, such as the UF fine composite material blend layer mentioned above.

[0322] Compared to coarse fibers, the particle size of thermoplastics used for fine fibers can be smaller. That is, to achieve effective coating of fine fibers, it is optimal to utilize thermoplastic particles with a finer average particle size to ensure good coating of fine lignocellulosic material fibers.

[0323] The crosslinking agents used in the fine mixture and the coarse mixture can be different. For example, the crosslinking agent used in the fine mixture can be selected based on its performance at higher temperatures, while the crosslinking agent used in the coarse layer can be selected based on its performance at lower temperatures.

[0324] The moisture content of the finer layers can be increased relative to that of the coarser layers.

[0325] The composite material mixture may also contain additives. Additives may be present in the binder. Additives may be selected from any one or more of the following: Accelerator, Modifier, Activator, and / or catalyst.

[0326] Regarding the accelerator, the accelerator can be an amine-based accelerator. More specifically, the accelerator can be a toluidine-based accelerator. Specifically, the accelerator can be selected from N-(2-hydroxyethyl)-N-methyl-p-toluidine, ethoxylated p-toluidine, N,N-dimethyl-p-toluidine, N,N-dihydroxyethyl-p-toluidine, diisopropoxy-p-toluidine, or combinations thereof.

[0327] The adhesive may contain 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, or 3.0% of an accelerator by weight of the adhesive, and a suitable range may be selected from any of these values.

[0328] Unwilling to be bound by theory, the accelerator increases the amount of free radicals through the crosslinking agent, which increases the polymerization rate of functionalized thermoplastic materials into thermosetting materials.

[0329] The produced boards can have a modulus of elasticity (MoE) of approximately 1,000, 1,500, 2,000, 2,500, 3,000, 3,500, or 4,000 MPa, and a suitable range can be selected from any of these values. Static bending is commonly used for mechanical stress grading (MSR) of wood-based products. MSR is currently the most common dynamic mechanical loading procedure. The board is fed longitudinally and laid flat through the machine and bent upward and downward by rollers in two sections. The span between the rollers is typically about 1.2 m. Depending on the design, the machine bends the board to a constant deflection and measures the required force, or the machine bends the board with a constant force and measures the deflection. Using the load-deflection relationship, the local MOE can be determined directly using equations derived from the fundamental mechanics of the material at every point on the board except for approximately the first and last 500 mm. This test method allows for the determination of the board's stiffness characteristics.

[0330] The manufactured composite panels have modulus of rupture (MOR) of approximately 5, 10, 15, 20, or 25 MPa, and a suitable range can be selected from any of these values. MOR (sometimes called flexural strength) is a measure of the strength of a specimen before it breaks. It can be used to determine the overall strength of wood-based products; unlike the modulus of elasticity, which measures the deflection of wood but not its final strength. MOR “σ” can be calculated using the equation σr = 3Fx / yz², using the load force F on the material and the dimensional scales in the three directions (x, y, and z). In this case, the load is the external force applied to the material of interest. The load force is applied to the center of the composite product of the material slightly above ground level.

[0331] In some embodiments, the composite material product has a surface screw holding force of about 200, 250, 300, 350, 400, 450 or 500 N, and a suitable range may be selected from any of these values ​​(e.g., about 200 to about 500, about 200 to about 400, about 200 to about 300, about 250 to about 500, about 250 to about 450, about 250 to about 350, about 300 to about 500, about 300 to about 450, about 350 to about 500, about 350 to about 450 N).

[0332] The density of composite panels can be controlled by the degree of compression applied in a press or mold. For example, lower pressures can be used to provide panels with densities of approximately 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, or 650 kgm³. 3 The density of the low-density composite board is such that a suitable range can be selected from any of these values.

[0333] Greater pressures can be used to provide pressures of approximately 650, 700, 750, or 800 kgm. 3 Medium density composite boards of a certain density, and a suitable range can be selected from any of these values.

[0334] Greater pressures can be used to provide pressures of approximately 800, 850, 900, 950, 1000, 1050, or 1100 kgm. 3 The density of the high-density composite board is such that a suitable range can be selected from any of these values.

[0335] In particleboard made from lignocellulose fibers, moisture resistance is important to prevent swelling, warping, or other deformation of the material. Swelling can lead to loss of structural integrity, performance, and / or durability.

[0336] Wood is particularly hydrophilic, and when wood fibers or other hydrophilic fibers are used in damp or humid environments, they can absorb water, which degrades the material.

[0337] Adding hydrophobic compounds (i.e., hydrophobic agents) to boards can increase their moisture resistance and prevent swelling, warping, and the development of mold or rot. During the manufacturing process, hydrophobic agents can be applied to the surface of the board or added to the wood fibers.

[0338] Common hydrophobic agents used in board manufacturing include natural or synthetic waxes, silicone-based compounds, and fatty acids and salts (such as stearates). The most common types of wax are paraffin wax, slack wax, and microcrystalline wax. Typically, when wax is used to impart moisture resistance in industrial wood fiberboard production, it is added at an amount of 0.75% of the total weight of the board. When wax is used to impart moisture resistance in particleboard production, it is typically added at an amount of 0.5% to 1.5% of the total weight of the board.

[0339] Paraffin wax is a cost-effective and readily available material that can be easily emulsified and sprayed onto wood fibers. It provides effective moisture resistance, reduces thickness swelling, and improves dimensional stability. However, paraffin wax has limited thermal stability, which can lead to deterioration at high temperatures, potentially affecting its performance during the hot pressing of particleboard. Furthermore, it may interfere with the adhesion between the resin and wood fibers, potentially reducing the internal bond strength of the board.

[0340] Oil-based waxes are less refined than paraffin wax, offering better adhesion properties. They also provide good moisture-proof properties similar to paraffin wax and are relatively inexpensive and widely used in industry. However, oil-based waxes can have inconsistent quality and composition, resulting in variable properties. Like paraffin wax, they also have lower thermal stability and can deteriorate at high temperatures, affecting their effectiveness during board production.

[0341] On the other hand, compared to paraffin and oil-based waxes, microcrystalline waxes have a higher melting point and better thermal stability, making them more suitable for high-temperature processing. They offer improved flexibility and toughness, enhancing the overall durability of the particleboard. Microcrystalline waxes provide excellent moisture resistance, significantly reducing swelling and improving dimensional stability. However, they are more expensive than paraffin and oil-based waxes, which may increase the production cost of particleboards. Furthermore, they may require more complex emulsification processes and equipment for effective application.

[0342] When isocyanate- and urea-formaldehyde-based adhesives are used under conditions exhibiting higher humidity, these resins are often modified with significantly more expensive compounds such as melamine, phenol, or resorcinol (see A. Pizzi (2014). Synthetic adhesives for wood panels: chemistry and technology - a critical review [Rev. Adhes. Adhes. 2, pp. 85–126). It has been previously reported that adding wax to isocyanate and urea-formaldehyde particleboards adversely affects the internal bonding (see Papadopoulos, AN (2006). Property Comparisons and Bonding Efficiency of UF and PMDI Bonded Particleboards as Affected by Key Process Variables. BioResources, 1(2), 201-208).

[0343] The thermoplastic dispersion disclosed herein can be used as a hydrophobic agent. That is, the thermoplastic dispersion disclosed herein can increase the moisture resistance of the sheet without compromising its strength. In one example, the sheet does not include moisture-resistant mixtures (such as waxes) other than the thermoplastic dispersion described herein.

[0344] In one instance, composite products manufactured using thermoplastic dispersions exhibited swelling of less than approximately 15%, 14%, 13%, 12%, 11%, and 10% when tested by a 24-hour swelling test. The 24-hour swelling test is also known as the immersion test. An example of the immersion test is given in British Standard EN 317-1993: Particle Boards & Wood Fiber Boards - Determination of Swelling after Immersion in Water. The immersion test specifies a method for determining the thickness swelling of flat-pressed particleboard and fiberboard. Thickness swelling is determined by measuring the increase in thickness of the test specimen after complete immersion in water for 2 hours (indicative result) and 24 hours (final result). The water absorption rate by weight and volume is determined by measuring the increase in weight and volume of the test specimen after complete immersion in water for 2 hours (indicative result) and 24 hours (final result).

[0345] The method for performing the immersion test (swelling test) is now described, as in the example described below. Two test specimens are taken from each plate. An example of a suitable size test specimen for the swelling test described herein is 50 x 50 mm ± 1 mm. During the procedure, holes (e.g., 3.5 mm holes) are drilled near the edges of the test specimens using a drill press. The holes allow the sample to be immersed in water. The test specimens are conditioned to a constant mass in an atmosphere of 65% ± 5% relative humidity and 20°C ± 2°C. A constant mass is achieved when the results of two consecutive weighing operations performed at 24-hour intervals differ by no more than 0.1%. The weight (m1) of each test specimen is measured, and the thickness at four points along the middle of each side is measured using calipers to calculate the average thickness (t1). The width and length of each sample are measured using calipers to allow the volume (v1) to be calculated. The test specimens are immersed in a temperature-controlled water bath by suspending them on a metal wire attached to a steel rod and ensuring that the test specimens are covered with at least 25 ± 5 mm of water. The water temperature should be maintained at 20°C ± 1°C for the duration of the procedure. After 2 hours, the samples are removed from the water bath and excess water is removed. The weight, thickness, and volume (m², t², v²) of each test piece are measured in the same manner as described above. The test pieces are then re-immersed, and after another 22 hours, the test samples are removed from the water bath and excess water is removed. The weight, thickness, and volume (m³, t³, v³) of each test piece are measured in the same manner as described above.

[0346] Calculate the 2-hour time (TS) based on the percentage of the original thickness using the following formula. 2h ) and 24 hours (TS)24h Thickness swelling (TS):

[0347]

[0348]

[0349] in t1 is the thickness of the test piece before immersion, in millimeters. t2 is the thickness of the test piece after 2 hours of immersion, in millimeters. t3 is the thickness of the test piece after 24 hours of immersion, in millimeters.

[0350] Calculate 2 hours (WA) using the following formula. 2h ) and 24 hours (WA) 24h Water absorption rate (WA) by volume:

[0351]

[0352]

[0353] in v1 is the volume of the test specimen before immersion, in cubic millimeters (mm). 3 ) v2 is the volume of the test specimen after 2 hours of immersion, in cubic millimeters (mm). 3 ) v3 is the volume of the test specimen after 24 hours of immersion, in cubic millimeters (mm). 3

[0354] Calculate 2 hours (WA) using the following formula. 2h ) and 24 hours (WA) 24h Water absorption rate (WA) by weight:

[0355]

[0356]

[0357] in m1 is the weight of the test piece before immersion, in grams. m2 is the weight of the test piece after 2 hours of immersion, in grams. m3 is the weight of the test specimen after 24 hours of immersion, in grams.

[0358] As shown in Example 14, even when wax was applied to the board, the board made with adhesive showed reduced swelling in the 24-hour swelling test compared to a board made with isocyanate only. The board with wax applied to the surface had reduced internal bond strength compared to a board made without a thermoplastic dispersion. However, the internal bond strength was the same compared to a board made with adhesive.

[0359] As shown in Example 15, the moisture resistance of the board increases with the increase of the amount of thermoplastic dispersion.

[0360] The composite material products described can have a variety of applications in industry.

[0361] For example, moisture-resistant composite products, as described, can exhibit enhanced durability and stability under wet or humid conditions.

[0362] In some instances, such as in the construction and building industry, these products can be provided as composite panels for use as exterior sheathing, providing additional insulation and moisture protection, roofing underlayment, or acting as a protective layer beneath roofing materials to improve weather resistance. These composite products can be used as a stable and durable base layer for rough flooring beneath finished floors, particularly in areas prone to moisture exposure such as bathrooms and kitchens. Furthermore, these composite panels can be used in both interior and exterior wall construction to enhance moisture resistance and structural integrity.

[0363] In some instances, such as furniture and cabinetry, moisture-resistant products can be used in the construction of kitchen cabinets. Kitchen cabinets are often exposed to high humidity and occasional water contact, as are bathroom vanities, where resistance to moisture and humidity is essential. Because of their ability to withstand exposure to these elements, such moisture-resistant products can also be used in outdoor furniture, such as garden furniture and decks.

[0364] In some instances, such as in the packaging industry, moisture-resistant products can be used as protective packaging materials to protect goods during transport and storage. Industrial applications can include their use in the construction of shipping containers and pallets that must withstand moisture and rough handling, as well as in sound insulation panels, where moisture resistance contributes to product durability.

[0365] In some instances, such as in retail environments, moisture-resistant products can be used in the construction of store fixtures (such as display units and shelves) where they may be exposed to varying humidity levels. Specific applications include outdoor signage and display panels requiring moisture resistance for extended lifespan, as well as certain types of sports equipment, such as skate ramps and other outdoor sports structures, where moisture resistance is important.

[0366] As described, moisture-resistant products can exhibit versatility and enhanced properties, making them suitable for many applications where conventional wood fiberboard is unqualified due to its susceptibility to moisture damage.

[0367] Currently, there are standards for moisture-resistant wood fiberboard, such as the European standard EN 312. European standard EN 312. P3 boards are designed for use as non-load-bearing components in damp conditions. The P3 classification ensures that wood fiberboard is suitable for indoor use in damp environments, such as kitchens, bathrooms, or utility rooms where moisture levels are higher than in standard living areas. The main characteristics and requirements of P3 boards include: • Moisture resistance: Compared to standard boards, P3 boards have enhanced moisture resistance, making them suitable for use in environments where they may be exposed to higher humidity levels but not in direct contact with water. • Internal bond strength: P3 boards must meet specific internal bond strength requirements to ensure they maintain structural integrity under humid conditions. • Thickness swelling: The standard sets limits on thickness swelling after exposure to moisture, indicating that P3 boards should not swell excessively when exposed to moisture. • Bending strength (MOR) and modulus of elasticity (MOE): P3 plates have specific requirements for bending strength and modulus of elasticity to ensure that they can withstand stresses encountered under wet conditions without deforming or breaking.

[0368] In some instances, such as the moisture-resistant products described, the products conform to the P3 standard as set forth above. Example Standard Method

[0369] Unless otherwise specified, the following test methods and board characteristics are used in the examples provided below: Table 1 - Standard methods used in this invention. Example 1 - Characterization of Thermoplastic Polymers Purpose

[0370] Analyzing various thermoplastic polymers as is to understand their composition and identity. This characterization is an important first step when using unknown waste / recycled plastics, especially when downstream processes (such as catalysis, functionalization, and emulsification) are sensitive to the identity and composition of the raw materials. method FTIR analysis

[0371] Analyzing industrial post-recycled LDPE (Astron), agricultural post-recycled LLDPE (Bale wrap or r-LLDPE), construction post-recycled LDPE (Building wrap or r-LDPE), and consumer post-recycled LLDPE (p-LLDPE) to assess the amount of PE and other polymers. Measurements were performed using a PerkinElmer Spectrum Two FT-IR instrument equipped with a diamond ATR attachment, according to the manufacturer's instructions. Measurements were taken at wavenumbers (cm²) from 450 to 4000. -1 ) below 1 cm -1 The average of four scans at the specified resolution was taken. For each blend, five different films prepared from randomly selected granules were measured. Data were processed and peak areas were analyzed using PerkinElmer Spectrum IR software. Data from the recycled polymers were compared with the FTIR spectra of unprocessed LDPE.

[0372] For 1350 cm -1 With 1380 cm -1 The peaks corresponding to CH3 bends and CH2 bends were deconvolved and analyzed to determine the variation between LLDPE and LDPE. Differential scanning calorimetry

[0373] Differential scanning calorimetry (DSC) analysis was performed on 2–4 mg of cut polymer pellets using a PerkinElmer DSC4000. Each sample underwent initial heating and cooling cycles to eliminate thermal history. The samples were then analyzed using the following thermal program: held at 30°C for 1 minute, heated from 30°C to 140°C at 20°C / min, then cooled from 140°C to 30°C at 20°C / min and held for 1 minute. Peaks were then integrated using Pyris software. The peak melting temperature, enthalpy of fusion, peak crystallization temperature, and enthalpy of crystallization were recorded. The following samples were analyzed: Table 2 - Analyzed plastic samples result

[0374] The results and conclusions related to each plastic are provided below: 1A - Results - Unprocessed LDPE (ExxonMobil LD104BR) pellets Table 3 - Properties of unprocessed LDPE (LD104BR) from Sample 1a of ExxonMobil

[0375] Figure 1a The DSC analysis of unprocessed LDPE is shown.

[0376] The FTIR spectrum reveals the characteristic peaks of LDPE. The melting peak in the DSC curve is at 114.3°C and exhibits a broad characteristic. This peak is an indicator of LDPE with non-uniform chain lengths. 1B - Results - Post-construction membrane (r-LDPE) analysis Table 4 - Properties of the membrane after sample 1B construction

[0377] Figure 1b The DSC analysis of the rPE membrane after construction is shown.

[0378] The FTIR spectrum of the membrane after construction showed that the sample was mainly composed of LDPE. In the DSC curve, a broad, single melt peak at 110.7°C indicated LDPE with non-uniform chain lengths. No visible MDPE, HDPE, or PP contamination was observed. 1C - Results - Analysis of Agricultural Post-Wrapping Film (Bundling Material) Table 5 - Properties of Sample 1C Agricultural Post-Film (r-LLDPE)

[0379] Figure 1c The DSC analysis of the r-PE film after the agricultural packaging is shown.

[0380] FTIR spectra indicate that the bundled contents are primarily composed of LLDPE. The first melt peak in the DSC curve at 122°C indicates LLDPE. The second peak at 111.5°C indicates LDPE. 1D - Results - Post-consumer Printed Recycled LLDPE (p-LLDPE) Table 6 - Characteristics of Sample 1D Post-Consumer Printed Recycled LLDPE (p-LLDPE)

[0381] Figure 1d The DSC of p-LLDPE is shown.

[0382] The first melting peak in the DSC curve is at 124.7°C, indicating LLDPE. The second peak at 111.5°C indicates LDPE. The broad peaks indicate that p-LLDPE is composed of polymers with non-uniform chain lengths. 1E - Results - Post-industrial granulated LDPE

[0383] Figure 1e The DSC analysis of sample 1E - post-industrial granulated LDPE is shown. Table 7 - Characteristics of Post-Industrial Granulated LDPE of Sample 1e

[0384] The first melting peak at 106°C in the DSC curve indicates LDPE. The broad peak indicates uneven chain length. The second melting peak at 125°C is sharp and indicates medium-density PE with uniform chain length. No visible HDPE or PP contamination is observed. Example 2A - Heat treatment of thermoplastics in an extruder

[0385] This example describes the processing of thermoplastics in an extruder at temperatures far above their melt temperature. The properties of the high-temperature extrudate as an adhesive in wood fiberboard were also investigated. method

[0386] Recycled agricultural post-LDPE film (bundled wrapping material (BWT)) is passed through a twin-screw extruder at several different processing temperatures, as shown below.

[0387] Using the following twin-screw extruder processing conditions, calculate the average barrel temperature (activation temperature) based on zone 3-8.

[0388] Thermoplastic dispersions were prepared by passing heat-treated thermoplastic granules through a twin-screw extruder. The extruder included two water injection points and a surfactant was used to stabilize the emulsion. The water flow rate was adjusted to achieve a resin:water ratio of 3.5 after injection point 1 and 1.3 after injection point 2. The thermoplastic dispersion was mixed with 1% pMDI by weight of the composite mixture and mixed for 10 minutes. The mixed formulation was distributed in a die on a press plate and flattened to prepare a felt with a consistent height and uniform distribution of material. The felt was pre-compressed at 5 tons of force and then subjected to hot pressing at a compression factor of 12 and a target density of 620 to produce compressed wood fiberboard. The MFI of the treated bundled package samples was measured.

[0389] Building cladding (r-LDPE film processed according to the same parameters as BWT4 above and compared with control building cladding samples extruded at 200°C. Mechanical tests were performed to understand the effect of heat-treated thermoplastic dispersions from recycled polyethylene - modulus of elasticity (MoE) and modulus of rupture (MoR).

[0390] Three replica plates were produced from different thermoplastic dispersions and their performance was tested according to the standards listed in Table 1. result Table 8. Processing temperatures for r-LLDPE samples extruded at different temperatures

[0391] Figure 2A (i) shows the average MFI of sample BWT1-4 relative to the average barrel temperature. Figures 2A (ii) and 2A (iii) show that the boards prepared using heat-treated thermoplastic dispersions from building cladding as adhesives are significantly superior to the control (not heat-treated to activation temperature).

[0392] MFI showed an unexpected increase at the average cylinder temperature between 300°C and 333°C.

[0393] This is possible due to the high processing temperatures of the extrudate. These high temperatures can cause chain breakage in the polymer chains, which leads to a reduction in viscosity and an improvement in melt flow behavior.

[0394] Higher processing temperatures above the melting point can also accelerate the reaction rate of polymers undergoing chemical transformation during processing. Not wanting to be bound by theory, the inventors propose that the improved melt behavior enhances polymer-wood chip compatibility, thereby improving the overall performance of wood fiberboard. Example 2B - Production of wood fiberboard using heat-treated recycled LDPE and pMDI thermoplastic dispersions

[0395] This example demonstrates the production of wood fiberboard using a thermoplastic dispersion produced from r-LDPE and pMDI as a crosslinking agent. Control panels were prepared using pMDI and without the thermoplastic dispersion for comparison. method

[0396] Thermoplastic dispersions were produced from heat-treated recycled LDPE (building cladding pellets) according to the parameters described in Example 2A. Thermoplastic dispersions and pMDI were added to sawdust to produce four replicates of 450 × 450 × 15 mm wood fiberboard with a compression factor of 12 seconds / mm. The boards contained 10% (w / w) thermoplastic dispersion with 1%, 2%, and 3% (w / w) pMDI. The remainder of the boards was sawdust. Control boards were prepared using 1%, 2%, and 3% (w / w) of sawdust and no thermoplastic dispersion. Four mechanical tests were performed to understand the effect of heat-treated thermoplastic dispersions from recycled polyethylene with pMDI as a crosslinking agent: modulus of elasticity (MoE), modulus of rupture (MoR), internal bond strength (IB), and a 24-hour immersion test. result

[0397] Figures 2B(i) to (iv) show that the boards produced using the combination of pMDI crosslinking agent and heat-treated thermoplastic dispersion as binder exhibit superior performance compared to the control boards. The results indicate that the use of thermoplastic dispersion from r-LDPE effectively enhances board performance at all pMDI loadings.

[0398] These figures also show that incorporating a thermoplastic dispersion as a binder into a board with 1% (w / w) pMDI as a crosslinking agent provides the board with performance approximately equivalent to the control board with 3% pMDI (w / w).

[0399] Examples show that the addition of heat-treated waste LDPE provides enhanced bonding of thermoplastics when incorporated into wood fiberboard containing pMDI crosslinking agents. Without being bound by theory, it appears that superior properties of boards containing thermoplastic dispersions are possible due to improved compatibility of the dispersion with wood chips and pMDI. It is also possible that the thermoplastics with improved melt behavior have been chemically activated (i.e., no longer inert) and are more efficient in dispersion through a wood chip matrix. Example 3 - Catalyst Screening

[0400] This example illustrates the treatment of extruded raw LDPE with various catalysts. During extrusion, 2.5 wt.% of catalyst was added to the raw LDPE. method Extrusion production Table 9 - Different catalysts used in this example.

[0401] Nine LDPE samples (C1 to C9) blended with different catalysts and one LDPE sample (C0) without catalyst were processed by a twin-screw extruder at 350°C. Unprocessed LDPE pellets were premixed with different catalysts (2.5% w / w) and fed into the extruder. Extruded polymer pellets were collected in batches from the twin-screw extruder, and their melt behavior was evaluated using MFI testing and molecular weight modification via rheology. Zero-shear (oscillatory) viscosity of the catalytic extrudates was obtained using an Anton Paar MCR 102e rheometer. The apparatus contained a 25 mm parallel plate system with Peltier temperature control. Data were analyzed using RheoCompass software, and complex viscosities were reported at melting point at 160°C. Control samples not processed by the extruder (heat-treated) were also included in the analysis (“Control” / “as is”). result Table 10 - Rheological properties of catalytically extruded unprocessed LDPE

[0402] Figure 3a and 3b The table shows a comparison of the melt flow index and viscosity of the samples listed in Table 11. The data indicate that the samples extruded using the Cu-O-based catalyst exhibit excellent flow and complex viscosity characteristics.

[0403] Analysis of molecular weight ( Figure 3c The results show a significant decrease in molecular weight in the copper oxide-treated samples. The polymers treated with copper oxide (II) have a molecular weight approximately 50% smaller than the control.

[0404] In the samples presented in this example, copper oxide had a significantly greater effect than the others. Not wishing to be bound by theory, the inventors believe that this is due to the following possible mechanism—Cu in copper(II) oxide, as a group XI transition metal. 2+ It is easily reduced to Cu due to its electronic configuration. +1 Cu outperforms other compounds. C 2+ The electronic configuration places a single electron in a high-energy d-orbital to become the more energy-stable Cu. 1+ Therefore, in the presence of atmospheric oxygen, Cu 2+ To Cu 1+ The reduction reaction attacks the CH bonds in LDPE and generates hydroxyl radicals, which in turn promote chain scission in LDPE. Reduced Cu 1+ It is very likely that it will be oxidized again to Cu at elevated temperatures. 2+ This also facilitates catalytic cycle transfer. Similar high-temperature redox behavior is expected to be observed in other Group XI metals such as Ag and Au. Example 4A - Effect of Copper Oxide (II) on Unprocessed LDPE

[0405] This example illustrates the effect of copper oxide catalysts on the melt behavior of unprocessed LDPE. method

[0406] Unprocessed thermoplastic granules from Exxon Mobil (LD104BR) were processed using a twin-screw extruder at an average barrel temperature of 350°C with varying amounts of copper oxide. A control sample without a Cu catalyst was also granulated via a twin-screw extruder at 350°C.

[0407] Three unprocessed LDPE samples (LD104 BR) from Exxon Mobil and one control LDPE were extruded via a twin-screw extruder using a CuO catalyst. The catalyst in this example was fed via a microfeeder. Table 11 - CuO content added in three different unprocessed LDPE samples. Results & Conclusions Table 12 - MFI and complex viscosity of CuO-catalyzed unprocessed LDPE

[0408] Figure 4A(i) shows the change in melt flow behavior with increasing catalyst dosage, and Figure 4A(ii) shows the change in complex viscosity with increasing Cu catalyst dosage. These figures indicate that melt flow behavior and viscosity are inversely proportional. These figures also show that the CuO catalyst exhibits effectiveness across a wide range of dosage schemes and can be more efficient for unprocessed LDPE at lower dosages. Example 4B - Different catalyst dosages in post-construction rPE method

[0409] Recycled LDPE pellets were processed using a twin-screw extruder at 350°C with varying amounts of copper oxide. 1 wt.%, 2 wt.%, and 3 wt.% CuO powder were fed into the extruder using a micro-feeder. Control r-LDPE samples without CuO catalyst were also extruded to evaluate changes in molecular properties. Table 13. Catalyst concentrations used for different samples. Results & Conclusions

[0410] The melt flow behavior and viscosity of the samples were analyzed and compared with control samples (pure building wrapping granules) extruded at 350°C to determine the effect of CuO on polymer properties.

[0411] Figures 4B(i) and 4B(ii) show that r-LDPE behaves in a manner similar to that of unprocessed LDPE described in Example 3A. In this example, CuO reduced the complex viscosity and increased melt flow by more than 60%. Although the differences in properties between the control sample and the copper oxide sample were significant, the increased Cu dosage only slightly altered the properties. Example 4: The effect of C-CuO catalyst on recycled linear low-density polyethylene. method

[0412] Agricultural-recycled LLDPE (r-LLDPE) and post-consumer printed LLDPE (p-LLDPE) pellets were processed at 350°C using a twin-screw extruder with 2.5 wt.% (polymer) copper oxide. A control sample without Cu catalyst was also extruded via twin-screw extrusion for comparison. Table 14 - Catalyst dosage in different linear LDPE samples. result

[0413] Figures 4C(i) and 4C(ii) show that CuO stoichiometry reduces the complex viscosity and increases the molecular weight index (MFI). The decrease in viscosity implies a decrease in the molecular weight of the polymer. In this example, the introduction of the CuO catalyst reduced the viscosity by 34% for r-LLDPE and by 40% for p-LLDPE. Example 5 - Preparation of thermoplastic dispersions from pre-constructed r-LDPE (2.5 wt.% Cu(II)O) using CuO catalysis method

[0414] Granules prepared with 2.5 wt% CuO according to the method described in Example 4B were passed through a twin-screw extruder, wherein the first zone was set above the melting point of the polymer, and subsequent zones were set at 95°C under a pressure of 10 bar. Water was added to achieve a final moisture content of 50% to 70% in the recycled thermoplastic dispersion.

[0415] Under the same conditions as mentioned above, the heat-treated r-LDPE granules (control sample) without Cu(II)O catalysis were also passed through a twin-screw extruder.

[0416] The particle size distribution (PSD) of thermoplastic dispersions was measured using a Bettersizer 2600 equipped with laser diffraction technology. The measuring instrument has a range from 0.02 μm to 2600 μm. The dispersion was added to the measuring chamber with water until a masking level of 5%–8% was achieved. The PSD value at the 50th percentile (D50) of the measurement was reported. result

[0417] Before being blended into sawdust to prepare 15 mm thick granular plates of 450 mm × 450 mm, the thermoplastic dispersion was collected and its PSD D50 was analyzed. The particle size of the dispersion used for copper oxide catalysis was reduced by 23%. Table 15. Particle size distribution of thermoplastic dispersions prepared from heat-treated r-LDPE pellets with and without 2.5 wt% Cu(II)O.

[0418] When passed through a twin-screw extruder, the reduced PSD of the CuO-catalyzed thermoplastic dispersion improves its properties. The resulting dispersion exhibits a unimodal particle size distribution and excellent stability. Example 6 - WFB plates prepared using thermoplastic dispersions from Example 4

[0419] This example describes the production of composite wood fiberboard using the thermoplastic dispersion prepared in Example 4. It also provides insights into the potential of using recycled thermoplastics with modified melt behavior as sustainable alternatives to enhance the processing and / or custom mechanical properties of wood fiber composites. method

[0420] Four mechanical tests were conducted to understand the effects of CuO-catalyzed r-LDPE and r-LLDPE dispersions on elastic modulus (MoE), modulus of rupture (MoR), internal bond strength (IB), and thickness swelling percentage (24-hour immersion).

[0421] Three replica plates were produced from different thermoplastic dispersions and their performance was tested according to the standards listed in Table 1. result

[0422] Figure 6 shows the average MoE, MoR, IB, and swelling thickness after a 24-hour immersion test. The results indicate that, for all tests, the CuO-catalyzed thermoplastic dispersion outperformed the control, and MoE, MoR, and IB surpassed the P3 industry standard.

[0423] The reduced viscosity of stable Cu(II)O-catalyzed thermoplastic dispersions may improve the distribution of dispersions in a wood chip matrix. Therefore, wood fiberboard exhibits excellent properties.

[0424] Improved melt behavior and dispersion stability of thermoplastic resins play a key role in enhancing the properties of wood chips (WFB). Not wishing to be bound by theory, the inventors hypothesize that the viscosity and melt behavior of the CuO-catalyzed thermoplastic dispersion provide improved affinity for wood chips compared to a control, thereby improving the MoE, MoR, and IB of the composite board. The enhanced compatibility between wood chips and the dispersion indicates that the dispersion exhibits improved wetting behavior for the wood chips. Consequently, the wood chips possess a more uniform polymer coating, leading to improved moisture resistance. Example 7 - Adhesive Production

[0425] This example demonstrates the preparation of wood fiberboard from thermoplastic dispersions using various LDPE raw materials and processing conditions. method Table 16 - Twin-screw extruder temperature configurations for different polymer samples

[0426] Three LDPE samples were processed using a twin-screw extruder at the temperature settings shown above. The polymer samples were premixed with polyvinyl alcohol (PVOH) granules (5% w / w and 10% w / w) and fed into the extruder feed to enhance processing efficiency. PVOH increased the flow of the samples through the twin-screw extruder, and no high-pressure / torque failure was observed. Water was added to achieve a final moisture content of 50%–70% in the thermoplastic dispersion.

[0427] Thermoplastic dispersions are collected from a twin-screw extruder and mixed with eMDI and wood fibers using a paddle mixer. Composite mixtures and sheets are produced according to the schemes described in Examples 2A and 2B, except that emulsified methylene diphenyl diisocyanate (eMDI) is used instead of pMDI. result Table 17 - Wood Fiberboard Pressing Parameters Physical test results of different adhesive sources for wood fiberboard Table 18 - Test Results of Wood Fiberboard Table 19 - Average MoE, MoR, and IB Table 20 - Wood fiberboard testing with differences in PVOH levels using unprocessed LDPE B

[0428] Unprocessed LDPE B has an MFI of 21.4, while unprocessed LDPE A has an MFI of 2 g / 10 mins. Both LDPE A and LDPE B provide thermoplastic dispersions for the preparation of wood fiberboard with excellent board properties. The level of PVOH in the binder affects the mechanical strength of the boards produced using the binder. In particular, 5% PVOH provides stronger boards compared to 10% PVOH. Furthermore, the addition of 5% PVOH enhances the melt flow of the thermoplastic through the extruder. The addition of PVOH is believed to provide additional hydroxyl groups that bind with isocyanate functional groups. Supersaturation with 10% PVOH has an adverse effect on the strength of the wood fiberboard. Example 8 - Production of Mixed Waste Polymer Adhesives

[0429] This example demonstrates the production of adhesives using recycled polypropylene and recycled polyethylene feedstocks. These represent high-melting-point thermoplastics (PP, melting point approximately 171°C) and low-melting-point thermoplastics (LDPE, melting point approximately 106°C). Three thermoplastic material treatments were tested: a. Recycled PP (Yuplene): Recycled industrial LDPE (Astron) 1:1 b. Recycled PP (Yuplene): Recycled industrial LDPE (Astron) 1:4 c. 100% recycled LDPE (Astron)

[0430] These three raw materials were processed using a twin-screw extruder to prepare thermoplastic dispersions. Wood fiberboard was produced using adhesives, and its strength properties were tested.

[0431] Three mechanical tests were conducted to understand the effect of varying the thermoplastic ratios – modulus of elasticity (MOE), modulus of rupture (MOR), and internal bond strength (IB). This example provides insights into the potential of using high-melting-point recyclable thermoplastics (such as PP) and low-melting-point recyclable thermoplastics (such as LDPE) as sustainable alternatives to enhance the processing and / or custom mechanical properties of wood fiber composite panels. method Adhesive preparation

[0432] Raw materials are passed through a twin-screw extruder to homogenize the material and mix different plastic sources to produce thermoplastic granules. The thermoplastic granules are then passed through a twin-screw extruder with added water to induce emulsification and particle size reduction, producing a thermoplastic dispersion.

[0433] Three replica plates were produced using an adhesive prepared from these three thermoplastic dispersions. The same twin-screw extruder emulsification conditions were used. Table 21 - Temperature distribution of adhesives used in twin-screw extrusion

[0434] The twin-screw extruder temperature distribution shown in the table above includes a higher initial temperature to allow the thermoplastic to melt before mixing.

[0435] The extruder includes two water injection points. Two surfactants—an anionic surfactant, Dowfax 2A-1, and a nonionic surfactant, Teric 463—are used at the corresponding first and second injection points. The surfactant input is adjusted to achieve a 4% surfactant w / w ratio with the resin. Water is injected at injection point 1 (after the melt zone) and injection point 2 (the dilution zone). The water flow rate is adjusted to achieve a resin:water ratio of 3.5 after injection point 1 and 1.3 after injection point 2.

[0436] During processing, torque (current, in amperes) readings on the twin-screw extruder were evaluated and graded from 1 – minimum processable / maximum current – ​​to 5 – maximum processable / minimum current. This indicates the processability of the recycled material and is related to energy consumption. Initial tests of LDPE after using the recycled industry failed due to extruder shutdown caused by high torque / current readings.

[0437] After processing in an extruder, the moisture content of the dispersion is adjusted by drying for 24 hours to achieve a composite mixture moisture content of 8%-12%. The thermoplastic dispersion is mixed with emulsified methylene diphenyl diisocyanate (eMDI) for 10 minutes. By weight, 1% of the composite mixture is eMDI. 500 g of coarse sawdust is added in two batches and mixed for 10 minutes each to prepare the composite mixture. Plate preparation

[0438] The mixed ingredients are distributed in a mold on a pressure plate and flattened to prepare a felt with a consistent height and uniform distribution of material. The felt is pre-compressed with a force of 5 tons and then subjected to hot pressing with a compression factor of 12 and a target density of 620 to produce compressed wood fiberboard. Board testing

[0439] MOE, MOR, and IB tests were performed on four strips from three replication plates / processes to investigate how different combinations of recycled PP and PE affect mechanical strength. Torque readings for each sample were evaluated during processing to provide indicators of machinability. result Table 22 - MOE, MOR, and IB for thermoplastic polymer blends

[0440] MOE - The above represents the average elastic modulus of the three treatment groups. 50% recycled PP has the lowest average MOE at 1774 MPa, while the MOE of LDPE alone is 1811 MPa. There is no significant trend in MOE (P>0.1), with higher LDPE indicating a higher MOE.

[0441] MOR - The above represents the average MOR for the three treatment groups. The average modulus of break for these three treatment groups is 11.817 MPa (50 / 50 = recycled PP / recycled LDPE), 12.82 MPa (20 / 80 = recycled PP / recycled LDPE), and 13.140 MPa (100% recycled LDPE). There is no significant trend towards higher MOR with higher LDPE content (p>0.05).

[0442] IB - The above represents the average IB of the three treatment groups. The average internal bond strength of these three different board compositions shows a negative correlation with the proportion of recycled LDPE. However, there was no significant difference in the average values ​​among the treatment groups (p>0.05).

[0443] Processability - As the PP content increases, the processability of the sample increases - that is, the energy required for processing is lower and the possibility of clogging is less.

[0444] Melt Flow Index - The following shows a significant increase in the melt flow index (measured at 190°C) as the proportion of LDPE in the blend increases. Table 23 - Melt Flow Index for PP:LDPR Blends

[0445] The results show that recycled high-melting-point thermoplastics and recycled low-melting-point thermoplastics, including blends of PP and LDPE, can be used to produce wood fiberboard without adverse effects on MOE or MOR. The processability of the blends increases with higher PP content. This experiment demonstrates that the described method can process materials with high melt temperatures to produce adhesives and wood fiberboard with improved processability, reduced energy consumption, and consistently high strength.

[0446] Recycled PP has a higher melt temperature of approximately 171°C. Recycled LDPE has a lower melt temperature of approximately 106°C. Increasing the proportion of PP in the blend leads to an increase in the melt flow index. This, in turn, provides a favorable reduction in torque and improved processability via a twin-screw extruder. This example demonstrates that blends of recycled PP and LDPE can provide viable wood fiberboard after extrusion processing. It also shows that the melt flow index can be increased by adding recycled PP to the blend, for example, at least 50% recycled PP in a blend of LDPE and PP provides enhanced processability and blendability. Example 9 - Characterization of recycled thermoplastic materials for enhanced processing

[0447] This example illustrates some of the pre-processing characterization steps used in the embodiments to tailor extrusion parameters in the methods and apparatus described herein. Specifically, this example provides numerical models for characterizing waste thermoplastic polymers to determine the PP:LDPE ratio and the adjustment of processing parameters. This enhances the processing and energy efficiency of the extrusion process by determining the properties of unknown thermoplastics and then adjusting the extrusion and optionally functionalization parameters of the process to prepare reinforced thermoplastic dispersions for sheet fabrication. Waste polypropylene (PP) is combined with waste low-density polyethylene (LDPE), and the melt flow index is measured at temperatures ranging from 190°C to 230°C according to ASTM D1238. result Figures 7a-7e Calibration plots are shown, which illustrate experimental results for different recycled PP:LDPE compositions versus the natural logarithm of the mean MFI at different setpoint temperatures from 190°C to 230°C. Table 24 - Linear modeling of different compositions of waste PP and waste LDPE at different temperatures.

[0448] Different set temperatures used for melt flow index testing provided linear regressions between the percentage of polypropylene (PP) and the melt flow index at different temperatures (190°C, 200°C, 210°C, 220°C, and 230°C). This linear relationship provides a method for determining the level of PP in mixed waste thermoplastic polymers. Determining the PP and LDPE composition allows extrusion emulsification modification to enhance the dispersion preparation of thermoplastics and the mechanical properties of wood fiberboard. Example 10 - Production of Composite Boards Using Isocyanates

[0449] This experiment describes the production of composite wood fiberboard made using a thermoplastic dispersion and an isocyanate variant polymer, methylene diphenyl diisocyanate (pMDI), and an emulsion of pMDI in water (eMDI). method

[0450] Thermoplastic dispersions were prepared from unprocessed LDPE A blended with 5% PVOH using a twin-screw extruder, following the methods and twin-screw configuration outlined in Example 3. Wood fiberboard was prepared according to the mixing and sheet pressing procedures outlined in Examples 2A and 2B. Two replicas were prepared. result

[0451] Figures 8a-8c show the average MOE, MOR, and IB of boards made using eMDI and pMDI. Compared with pMDI MOE (2077.5 MPa), MOR (13.63 MPa), and IB (0.7 MPa), eMDI exhibits higher average MOE (2247.07 MPa), MOR (14.23 MPa), and IB (0.825 MPa).

[0452] High-quality wood fiberboard is produced using eMDI and pMDI, which are LDPE thermoplastic dispersions. Compared to pMDI, eMDI offers higher strength boards. Example 11 - Alternative Lignocellulosic Materials Purpose

[0453] This example study may include several lignocellulosic substrates within a composite board containing the thermoplastic dispersion described herein. method

[0454] Two lignocellulosic substrates were tested in comparison to pine sawdust: pea straw and barley straw. Pea and barley straw have a coarse, fibrous texture and are commonly used for water retention in horticultural and agricultural applications. Mechanical strength was tested according to standard methods.

[0455] pMDI was used as a crosslinking agent at 10 wt% of the adhesive. A thermoplastic dispersion containing LDPE (Exxon) was used. The twin-screw configuration used for dispersion preparation was as described in Examples 2A and 2B. The melt flow index of the polymer was 2 g / 10 mins at 190°C. The moisture content of the lignocellulose matrix was normalized to 10 wt%. 10 wt% of the board composition consisted of the adhesive. A 10 mm thick board with a weight of 620 kg / m³ was prepared. 3 The board is used for testing. result

[0456] The mechanical strength test results for each type of plate are shown below:

[0457] Table 25 - Strength test results of boards prepared using alternative substrates.

[0458] As measured by MOR and MOE, boards made from barley straw exhibit the highest mechanical strength. Barley straw typically has a higher lignin content compared to some other crop residues. The lignin content in barley straw is estimated to be in the range of 15%–20%, while that in pea straw ranges from 5%–15%.

[0459] This experiment demonstrates that a range of lignocellulose substrates can be used to produce composite boards. Example 12 - Optimizing the Adhesive Content in Wood Fiberboard Using Recycled Thermoplastic Dispersions

[0460] This case study examines various ratios of adhesives to crosslinking agents used in the production of composite boards containing wood fibers. method

[0461] Thermoplastic dispersions were prepared in a twin-screw extruder. The thermoplastics comprised unprocessed LDPE B (MFI: 20 g / 10 mins, 190°C) blended with twin-screw feed and then emulsified to improve processability, along with 5% PVOH (wt%). Wood fiberboard was extruded at 620 kg / m³. 3 Density formulation.

[0462] Table 26 - Temperature distribution in a twin-screw extruder

[0463] Table 27 - Composite Board Pressing Parameters.

[0464] Adjust the adhesive ratio and isocyanate (eMDI) content to find the optimal ratio. result

[0465] Table 28 - Composite Panel Characteristics.

[0466] Figure 9A shows the variation of the elastic modulus (MoE) under different plate treatments. Figure 9b The variation of the modulus of rupture (MoR) is shown under different plate treatments. Figure 9c The internal bond strength (IB) is shown for different plate treatments. Figure 9d The swelling rate (SB) is shown over 24 hours on different plate treatments.

[0467] The results showed that a high concentration of isocyanate (sample 4) provided the best mechanical properties (MoE and MoR). The board contained 90% lignocellulose material by weight. The mixture of thermoplastic dispersion and isocyanate provided good dispersion throughout the board and resulted in high strength.

[0468] The internal bond strength is determined by the interaction between the lignocellulosic fibers and the binder containing a thermoplastic dispersion. Optimal performance with a strength of 1.19 MPa was achieved using 10% binder and 2% isocyanate. The relatively high isocyanate content enhances the adhesion between the wood fibers and the binder.

[0469] The swelling rate of wood particleboard depends on the sawdust content. Figure 19d shows that increasing sawdust content and reducing adhesive content leads to an increased swelling rate. This may be partly due to the adhesive providing reduced porosity and thus increasing water resistance within the board. The enhanced hydrophobicity of the adhesive is also believed to contribute to this beneficial property of boards containing adhesive. Example 13 - Recycled thermoplastic dispersions for making wood fiberboard

[0470] This example describes the preparation of thermoplastic dispersions from four different waste thermoplastics (low-density polyethylene and polypropylene) and one unprocessed LDPE. The preparation of a composite board incorporating wood fibers is also described. method

[0471] The thermoplastic sample is prepared into pellets and fed into a twin-screw extruder with the configuration outlined below. The water flow rate is adjusted to achieve a moisture content of 45% to 55% in the thermoplastic dispersion.

[0472] Two samples of PE / PP blends with a 1:1 ratio were prepared to enhance post-extrusion processability and reduce the particle size of the thermoplastic dispersion. The first sample contained a 1:1 ratio of industrial post-LDPE (Astron) and recycled PP. The second sample contained a 1:1 ratio of agricultural post-LDPE film and recycled polypropylene. Each blend was subjected to a first twin-screw extruder for mixing and then to a second twin-screw extruder for preparing the thermoplastic dispersion.

[0473] Table 29 - Temperature Distribution in Twin-Screw Extruders

[0474] The TSE temperature distribution for all samples remained constant.

[0475] Table 30 - Plates with constant parameters formed in all samples

[0476] For each treatment, two replica plates were prepared. The moisture content of the prepared adhesive was evaluated. result

[0477] Table 31 shows processability metrics that depend on the thermoplastic source and any modifications (e.g., blending with PP).

[0478] Table 32 - Moisture content and composite plate results (average of two replicated plates)

[0479] Figures 10a-10d The swelling results for MoE, MoR, IB, and 24 h are shown.

[0480] Twin-screw extruder torque and current data illustrate the binder processability for each processing step. Torque measured in a twin-screw extruder reflects the shear forces capable of inducing mixing within the TSE. Polymers with high melt flow index (MFI), such as unprocessed LDPE A and recycled PP, exhibit lower torque. Blending of polymers (specifically Astron / rePP and bundled wrapper / rePP) when combined with the high MFI of recycled PP results in reduced torque.

[0481] MoE and MoR indicate that all processed thermoplastic dispersions provide adhesive compositions with acceptable sheet properties. Post-industrial LDPE (Astron) exhibits superior performance compared to other types of waste thermoplastic dispersions.

[0482] Unprocessed LDPE exhibits stronger composite sheets. This is believed to be due to additives or contaminants in waste thermoplastics that interfere with the bonding properties of the crosslinking agents.

[0483] Internal bond strength determines the bond between the wood fibers and the polymer adhesive. These four different waste polymer adhesives provided similar internal bond strengths of approximately 0.2–0.3 MPa.

[0484] Unprocessed LDPE A adhesive exhibits an internal bond strength of 0.5 MPa, twice that of adhesive sheets based on waste thermoplastic polymers. This indicates that waste thermoplastics can lose bond strength due to additives or contaminants. The methods described herein, such as treatment or functionalization using heat or catalysts, represent inventive steps toward controlling and improving the harmful properties of the waste thermoplastics used. These inventive steps represent significant progress in the ability to process difficult raw materials, such as waste LDPE or PP film and other waste plastics.

[0485] The swelling rate observed in water over a 24-hour period indicates a significant tendency for water absorption in recycled polypropylene sheets. This swelling rate appears to depend on the moisture content of the sheets before and during the preparation process. Interestingly, contrary to expectations, sheets with lower initial moisture content exhibited higher water absorption and were more prone to swelling. Experimental results show that, with a moisture content of 9.14%, the recycled polypropylene sheets swelled by more than 60% over a 24-hour timeframe. Furthermore, both Astron's 8% moisture content and Astron / PP's 9.53% moisture content (which are considered low) showed increased swelling rates over the 24-hour period. Example 14 - Production of composite boards containing thermoplastic dispersions and crosslinking agents, with and without wax.

[0486] This example compares the performance of composite panels made with 3% isocyanate with or without Aquawax 88 Gen wax coating. method

[0487] Composite panels 14A and 14B are control samples made using dimensionally reduced pine sawdust and 3% pMDI. Composite panels 14C and 14D were made using dimensionally reduced pine sawdust, 3% pMDI, and 10% thermoplastic dispersion (made from recycled building cladding) according to the process of BWT4 in Example 2A. Aquawax 88 Gen was applied to composite panels 14B and 14D at a rate of 0.75% of the panel weight.

[0488] Table 33 - Plate Composition Parameters.

[0489] The evaluation panel was tested for its performance in terms of strength, stiffness, bond strength, and swelling. result

[0490] Table 34 - Performance characteristics of plates with and without wax.

[0491] There was no significant difference in MOR and MOE between boards without wax and boards containing wax.

[0492] Significant differences exist between IB in plate samples 14A and 14B compared to plate samples 14C and 14D, which were made from heat-treated thermoplastic dispersions.

[0493] The control panel containing wax (without thermoplastic dispersion) showed some improvement in swelling resistance (from 33.58% to 23.26%). However, for both the wax-free and wax-containing panels, the sample containing thermoplastic dispersion showed an improvement in swelling resistance (i.e., increased moisture resistance), decreasing to only 10.85% and 10.64%, respectively. Furthermore, compared to the control panel (regardless of whether the control panel contained wax), the panel containing thermoplastic dispersion exhibited enhanced strength (MOR) and stiffness (MOE). Example 15 - Comparison of different amounts of thermoplastic dispersions at 1% isocyanate

[0494] This example compares the performance of sheets made with 1% isocyanate and 10%, 15%, and 20% thermoplastic dispersions by weight of the sheet, in the case of 1% isocyanate. method

[0495] Based on the parameters outlined for BWT4 in Example 2A, 10%, 15%, and 20% thermoplastic dispersions made from recycled post-industrial LDPE film (building cladding) were used to make boards with 1% pMDI.

[0496] Table 35 - Performance characteristics of plates with different amounts of thermoplastic dispersion.

[0497] Increasing the amount of thermoplastic dispersion resulted in a decrease in thickness swelling during swelling tests, with even 10% thermoplastic dispersion showing almost three times less swelling than the absence of thermoplastic dispersion. Thickness decreased with increasing thermoplastic dispersion amount.

[0498] The plates containing thermoplastic dispersions all exhibited similar MOR and IBS, which were higher than the control plate. Plates with 10% thermoplastic dispersions showed increased MOE, which decreased with increasing amounts of thermoplastic dispersion.

Claims

1. A method for producing a thermoplastic dispersion, comprising: Applying heat to thermoplastics to produce molten thermoplastics. The molten thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles. The molten thermoplastic is subjected to a processing step, which is selected from... i) Heating the thermoplastic at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both.

2. A method for producing a thermoplastic dispersion, comprising: Applying heat to thermoplastics to produce molten thermoplastics. The molten thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles. The molten thermoplastic is subjected to a processing step, which is selected from... i) Heating the thermoplastic at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both, and This processing step a) Reduce the melt flow index of the thermoplastic. b) Reduce the viscosity of the thermoplastic. c) The average molecular weight distribution of the thermoplastic is reduced by more than 35%, or d)(a) to (c) any one or more of them.

3. The method as described in claim 1 or 2, wherein, This processing step is applied during the melting or dispersion of the thermoplastic.

4. The method according to any one of claims 1 to 3, wherein, This treatment step resulted in an average decrease in the molecular weight of the thermoplastic by more than 30%.

5. The method according to any one of claims 1 to 4, wherein, The processing step includes heating at an activation temperature greater than 300°C.

6. The method according to any one of claims 1 to 5, wherein, The metal catalyst is selected from the group consisting of group XI transition metal catalysts, group XI transition metal oxide catalysts, copper catalysts, copper oxide catalysts, copper oxide (I), copper oxide (II), copper sulfate (II), silver catalysts, silver oxide (I), silver oxide (II), gold catalysts, metal catalysts with a single s orbital electron in the outer electron shell, metal acetate catalysts, and zinc acetate.

7. The method according to any one of claims 1 to 5, wherein, The metal catalyst is copper oxide.

8. The method according to any one of claims 1 to 7, wherein, The metal catalyst is added at a rate of 0.01% to 100% by weight of the thermoplastic.

9. The method according to any one of claims 1 to 8, wherein, The thermoplastic and the metal catalyst were added to the extruder.

10. The method of claim 9, wherein, After emulsification, the extruder includes a dilution zone for adding additional water to obtain a thermoplastic-to-water ratio of approximately 0.8:1 to 1.8:

1.

11. The method according to any one of claims 1 to 10, wherein, A crosslinking agent is added to the thermoplastic dispersion to produce an adhesive.

12. The method of claim 11, wherein, The crosslinking agent is selected from organic peroxides or isocyanates.

13. The method of claim 12, wherein, Isocyanate is added at 5% to 50% by weight of the adhesive.

14. The method of any one of claims 12 or 13, wherein, This isocyanate is a diisocyanate.

15. A method for producing a thermoplastic composite product, comprising mixing a thermoplastic dispersion as claimed in any one of claims 1 to 10 or an adhesive as claimed in any one of claims 11 to 14 with fibers to form a composite mixture, and applying heat and pressure to the composite mixture in a press or mold to form a thermoplastic composite product.

16. The method of claim 15, wherein, The fiber is selected from glass fiber, carbon fiber, aramid fiber and combinations thereof.

17. The method of claim 15, wherein, The fiber is selected from lignocellulose materials, which are selected from sawdust, wood fiber, wood pellets, wood chips, wood chips, coconut shells, straw or rice husks, barley straw, bamboo, palm leaves or combinations thereof.

18. The method of any one of claims 15 to 17, further comprising the step of forming a thermoplastic composite product, wherein the composite mixture has a moisture content of about 5% to about 15%.

19. The method according to any one of claims 1 to 18, wherein, The thermoplastic includes at least one of LDPE, HDPE, LLDPE and PP.

20. The method according to any one of claims 1 to 18, wherein, Sources of thermoplastics include high-melting-point thermoplastics such as polypropylene and low-melting-point thermoplastics such as polyethylene, or combinations thereof.

21. The method of claim 20, wherein, The ratio of high-melting-point thermoplastics to low-melting-point thermoplastics ranges from 1:4 to 4:

1.

22. The method according to any one of claims 1 to 21, wherein, The sources of this thermoplastic include waste thermoplastic.

23. The method according to any one of claims 1 to 22, wherein, The molten thermoplastic is reacted with a coupling agent to produce a functionalized thermoplastic, thus defining the functionalization stage.

24. The method of claim 23, wherein, This functionalization stage takes place in the functionalization zone of the extruder.

25. The method of claim 23 or 24, wherein, The coupling agent is selected from graft compatibilizers or active hydrogen donors.

26. The method according to any one of claims 23 to 25, wherein, The coupling agent is selected from glycidyl methacrylate, maleic anhydride, acrylic acid, glycidyl methacrylate, N-vinylformamide, bismaleimide, or silane.

27. The method according to any one of claims 23 to 26, wherein, At least a portion of the thermoplastic is reacted with an initiator in the extruder.

28. The method according to any one of claims 11 to 27, wherein, The moisture content of the thermoplastic dispersion or the adhesive is from about 25% to about 75%.

29. The method according to any one of claims 1 to 28, wherein, The plastic particles in the thermoplastic dispersion or the adhesive have a length of less than 0.5 mm in any orientation or axis.

30. The method according to any one of claims 1 to 29, wherein, The thermoplastic is subjected to a pre-processing step, which includes... a) Increase the melt flow index of the thermoplastic. b) Wash the thermoplastic. c) Crush the thermoplastic to reduce the variance of its particle size. d) Standardization of particle size and / or density, e) Granulate to a particle size of 2-8 mm, or any combination of one or more of f)(a) to (e).

31. The method according to any one of claims 1 to 30, wherein, The thermoplastic is subjected to a characterization step, which analyzes one or more physical properties of the thermoplastic.

32. The method according to any one of claims 1 to 31, wherein it is used in the manufacture of: a) Lignocellulose thermoplastic composite products, b) Synthetic fiber composite products, or c) Concrete composite material products.

33. The method according to any one of claims 1 to 32, used in the manufacture of a lignocellulosic thermoplastic composite board, the lignocellulosic thermoplastic composite board having a) Elastic modulus between about 1,000 and about 4,000 MPa b) Fracture modulus of approximately 10 to approximately 25 MPa c) Screw holding force of approximately 200 to approximately 500 N d) A density of approximately 550 to approximately 1,100 kg / m³, or e)(a) to (d) any combination of one or more of them.

34. A method for manufacturing a moisture-resistant composite material product, comprising: Obtain a thermoplastic dispersion, which is produced by the following manner. • Heating thermoplastics to produce molten thermoplastics, • The thermoplastic was then dispersed in water under stirring to produce a thermoplastic dispersion containing thermoplastic particles, and •The process involves subjecting the thermoplastic to treatment steps; The thermoplastic dispersion is combined with a crosslinking agent and fibers to produce a composite material mixture, and Heat and pressure were applied to the composite mixture to form a moisture-resistant composite product, which exhibited less than about 15% swelling after 24 hours when measured by a 24-hour swelling test.

35. The moisture-resistant composite material product as described in claim 34, wherein, This processing step is selected from i) Heating the thermoplastic at the activation temperature, ii) Add a metal catalyst, or iii)(i) and (ii) both.

36. The moisture-resistant composite material product as described in claim 34 or 35, wherein, The crosslinking agent is present in an amount of 0.5% to 5% by weight of the composite product.

37. The moisture-resistant composite material product according to any one of claims 34 to 36, wherein, The product exhibits swelling of less than approximately 14%, 13%, 12%, 11%, or 10% over 24 hours.

38. The moisture-resistant composite material product according to any one of claims 34 to 37, wherein it does not contain any moisture-resistant mixture other than the thermoplastic dispersion.

39. The moisture-resistant composite material product as described in claim 38, wherein, The moisture-resistant mixture is wax.

40. A composite board comprising: a) Waste thermoplastic plastics; b) Lignocellulose materials; and c) Metal catalysts, The lignocellulose material accounts for at least 75% of the composite board.

41. A composite board comprising: a) Waste thermoplastic plastics; b) Lignocellulose materials; and c) Crosslinking agent, The lignocellulose material comprises at least 75% of the composite board, and When measured by a 24-hour swelling test, the composite board exhibited a swelling of less than approximately 15% over 24 hours.

42. The composite panel as claimed in claim 41, wherein, The crosslinking agent is present in an amount of 0.5% to 5% by weight of the thermoplastic dispersion.

43. The composite panel as described in claim 41 or 42, wherein, The plate exhibited swelling of less than approximately 14%, 13%, 12%, 11%, or 10% over 24 hours.

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