Novel artificial board and preparation method thereof

Abstract

The invention discloses a novel artificial board and a preparation method thereof.The novel artificial board comprises a core layer and two surface layers located on the surface of the outer side of the core layer, the thickness of the core layer is 60-80% of that of the novel artificial board, and the core layer is prepared from, by weight, 20-40 parts of polymer rubber powder, 60-80 parts of wood raw materials, 1-4 parts of dispersing agent and 0.02-0.16 part of antioxidant; the surface layer comprises the following raw materials in parts by weight: 10-20 parts of an adhesive and 80-90 parts of a wood raw material. According to the scheme, the macromolecular hot melt adhesive prepared from maleic anhydride grafted polyolefin is adopted as the adhesive, no organic solvent or formaldehyde is added in the whole processing process, and the environmental protection performance is improved. And meanwhile, the adhesive and the wood raw material have extremely high affinity, so that the mechanical strength of the hot-pressed board is improved. In addition, the polyolefin material serving as a non-polar hydrophobic material can permeate into the wood fibers under the conditions of high temperature and high pressure, so that the wood fibers are well wrapped, and the overall moisture-proof performance of the board is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of artificial boards, and in particular to a novel artificial board and a preparation method thereof. Background Art

[0002] Medium density fiberboard (MDF) and particleboard are common man-made boards in furniture manufacturing, interior decoration and other fields.

[0003] Among them, medium-density fiberboard (MDF) is made by mixing wood fiber or other plant fiber with synthetic resin adhesive and pressing under high temperature and high pressure, while particleboard is made by adding sawdust and powder and other wood debris and pressing with synthetic resin adhesive. The main advantage of particleboard is low cost, but it is more likely to absorb water and deform, affecting normal use. The above two types of boards use more liquid adhesives, which will release more formaldehyde, and have relatively weak nail holding power, which is not suitable for frequent disassembly. Summary of the invention

[0004] In view of the above defects, the technical problem to be solved by the present invention is to provide a new type of artificial board and a preparation method thereof, so as to solve the problem that the artificial board manufactured by the prior art has relatively weak nail holding force or is easy to absorb water and deform.

[0005] To this end, the first aspect of the present application provides a new type of artificial board, comprising a core layer and two surface layers located on the outer surface of the core layer, wherein the thickness of the core layer is 60-80% of the thickness of the new type of artificial board.

[0006] The core layer comprises the following raw materials in parts by weight: 20-40 parts of polymer rubber powder, 60-80 parts of wood raw materials, 1-4 parts of dispersant and 0.02-0.16 parts of antioxidant;

[0007] The surface layer comprises the following raw materials in parts by weight: 10-20 parts of adhesive and 80-90 parts of wood raw materials.

[0008] In the above technical solution, preferably, the polymer adhesive powder is obtained by compounding polyolefin hot melt adhesive powder and polymer resin powder, in parts by weight: 5-35 parts of polyolefin hot melt adhesive powder and 2-35 parts of resin powder.

[0009] In the above technical solution, preferably, the high molecular polymer resin powder can be selected from one or more of powdered low-density polyethylene, high-density polyethylene, polypropylene, and nylon 6, and the raw material can be crushed into 40-80 meshes using a plastic grinder.

[0010] In the above technical solution, preferably, the polyolefin hot melt adhesive powder can be maleic anhydride grafted polyolefin.

[0011] In the above technical solution, preferably, the wood raw material used for the surface layer is the same as the wood raw material used for the core layer.

[0012] In the above technical solution, preferably, the adhesive is a urea-formaldehyde resin adhesive.

[0013] In the above technical solution, preferably, the adhesive is diphenylmethane diisocyanate glue.

[0014] In the above technical solution, preferably, the adhesive is the same as the polymer rubber powder used in the core layer.

[0015] The second aspect of the present application provides a method for preparing the above-mentioned novel artificial board, comprising the following steps:

[0016] Drying the wood raw material to control the moisture content below 3wt%;

[0017] Prepare the raw materials according to the composition ratio of the surface layer and the core layer, and evenly disperse them through a mixer to obtain the surface layer paving raw materials and the core layer paving raw materials;

[0018] First, a layer of surface paving material is laid on the base, then a core layer of paving material is laid, and finally, a layer of surface paving material is laid on the core layer of paving material;

[0019] Pre-press the laid board material to obtain a rough embryo of a new type of artificial board;

[0020] The rough blank of the new artificial board is hot-pressed under high temperature and high pressure to completely melt the polymer rubber powder into shape, and the finished new artificial board is obtained after cooling.

[0021] In the above method, preferably, the pre-pressing process parameters are: hot pressing temperature 100-140°C, hot pressing time 10-60s, hot pressing pressure 5-12MPa; hot pressing process parameters are: hot pressing temperature 160-240°C, hot pressing time 180-600s, hot pressing pressure 8-20MPa.

[0022] It can be seen from the above technical solutions that the new artificial board and its preparation method provided by the present invention solve the problems of the prior art that the nail holding force is relatively weak or it is easy to absorb water and deform. Compared with the prior art, the present invention has the following beneficial effects:

[0023] The polymer hot melt adhesive prepared by maleic anhydride grafted polyolefin is used as an adhesive, and the artificial board is obtained by hot pressing process. No organic solvent and formaldehyde are added during the whole processing process, which improves environmental performance. At the same time, the polarity of the maleic anhydride group is similar to the hydroxyl polarity in the wood, so that the adhesive has a strong affinity with the wood raw material, and the mechanical strength of the hot pressing board is improved. In addition, the polyolefin material, as a non-polar hydrophobic material, can penetrate into the inside of the wood fiber under high temperature and high pressure conditions, well wrap the wood fiber, and enhance the overall moisture resistance of the board. Thus, the new artificial board prepared by the present application not only has excellent mechanical properties and moisture resistance, but also does not add organic solvents and formaldehyde during the preparation process, fully demonstrating environmental characteristics and high strength advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces and describes the drawings required for use in the embodiments of the present invention or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A cross-sectional view of the novel wood-based panel provided for this application;

[0026] Figure 2 This is a flow chart of the preparation method of the new artificial board provided in this application. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] In order to more clearly explain and illustrate the technical solution and implementation of the present invention, several preferred specific embodiments for implementing the technical solution of the present invention are introduced below.

[0029] It should be noted that the directional words such as "inside, outside", "front, back" and "left, right" in this article are expressed based on the product usage status. Obviously, the use of the corresponding directional words does not constitute a limitation on the protection scope of this scheme.

[0030] At present, the common artificial boards in furniture manufacturing, interior decoration and other fields are medium-density fiberboard (MDF) and particleboard. Among them, medium-density fiberboard uses a lot of liquid adhesive, which will release more formaldehyde and has relatively weak nail holding power. Particleboard not only has weak nail holding power, but is also more likely to absorb water and deform, affecting normal use.

[0031] In this application, a polymer hot melt adhesive prepared by grafting maleic anhydride with polyolefin is used as an adhesive, and an artificial board is prepared by a hot pressing process. No organic solvent and formaldehyde are added during the entire processing process, thereby improving environmental protection performance. At the same time, the polarity of the maleic anhydride group is similar to the polarity of the hydroxyl group in the wood, so that the adhesive has a strong affinity with the wood raw material, thereby improving the mechanical strength of the hot-pressed board. In addition, as a non-polar hydrophobic material, the polyolefin material can penetrate into the wood fiber under high temperature and high pressure conditions, well wrap the wood fiber, and enhance the overall moisture-proof performance of the board.

[0032] Specifically, Figure 1 As shown, the new artificial board provided by the present application comprises a core layer 10 and a surface layer 20 located on the outer surface of the core layer 10, wherein the thickness of the core layer 10 is 60-80% of the thickness of the new artificial board.

[0033] The core layer 10 comprises the following raw materials in parts by weight: 20-40 parts of polymer rubber powder, 60-80 parts of wood raw materials, 1-4 parts of dispersants and 0.02-0.16 parts of antioxidants.

[0034] The polymer adhesive powder is compounded by polyolefin hot melt adhesive powder and polymer resin powder, and the weight proportions are as follows: 5-35 parts of polyolefin hot melt adhesive powder and 3-17 parts of polymer resin powder.

[0035] The polymer resin powder can be selected from one or more of powdered low-density polyethylene, high-density polyethylene, polypropylene, and nylon 6, such as one or more of LDPE 7042, HDPE 8008, PP K8003, and Shijiazhuang Refining Nylon PA 6, and the compounding is not limited. One embodiment is compounded by weight: (3-8): (2-10): (4-9), that is, the weight of one component can be 3-8, the weight of another component can be 2-10, and the weight of the third combination can be 4-9. The above raw materials can be crushed to 40-80 meshes by a plastic mill.

[0036] Polyolefin hot melt adhesive powder can be selected from maleic anhydride grafted polyolefins, for example, maleic anhydride grafted polyolefins from China Science and Technology Pioneer Engineering Plastics National Engineering Research Center Co., Ltd. 2120.

[0037] The wood raw material is sawdust or wood powder obtained by crushing natural wood, such as poplar wood powder of 60 mesh and poplar sawdust of 10 mesh.

[0038] Liquid paraffin is used as the dispersant.

[0039] The antioxidant can be selected from hindered phenols, hindered amines, and thioesters, or a mixture of two or more thereof, for example, any one or a mixture of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-p-cresol, or didodecaproic acid, and the mixing ratio is not limited.

[0040] The surface layer 20 includes the following raw materials in parts by weight: 10-20 parts of adhesive and 80-90 parts of wood raw materials.

[0041] The wood material used for the surface layer 20 is the same as the wood material used for the core layer 10 .

[0042] There are three options for using adhesives for the surface layer 20: one is urea-formaldehyde resin adhesive; the second is isocyanate adhesive, such as diphenylmethane diisocyanate (MDI) adhesive; the third is polymer rubber powder, which is the same as the polymer rubber powder used in the core layer 10, but the proportion of the rubber powder added can be smaller than that of the core layer.

[0043] Several typical embodiments of the core layer are shown in Table 1 below.

[0044] Table 1, core layer composition example.

[0045]

[0046]

[0047] Several typical embodiments of the surface layer are shown in Table 2 below.

[0048] Table 2, surface layer component composition example.

[0049]

[0050] The second aspect of the present application provides a method for preparing the novel artificial board, such as Figure 2 As shown, the method comprises the following steps:

[0051] Step 110, raw material processing.

[0052] The sawdust or wood powder after wood processing is selected as the wood raw material for drying, and the moisture content is controlled below 3wt%.

[0053] For example, poplar wood powder of 60 mesh or poplar wood sawdust of 10 mesh is dried at 103° C. for more than 4 hours, and the moisture content is controlled below 3 wt %.

[0054] Step 120, mixing raw materials.

[0055] Prepare the raw materials according to the component ratio of the surface layer and the core layer, and disperse them evenly through a mixer to obtain the surface layer paving raw materials and the core layer paving raw materials.

[0056] Step 130, paving the board.

[0057] First, lay a layer of surface paving material on the base to ensure it is flat and even, then lay the core layer paving material, and finally, lay another layer of surface paving material on the core layer paving material. Make sure that each layer of paving material is tightly combined.

[0058] Step 140: pre-pressing and forming.

[0059] The laid board materials are pre-pressed to obtain a rough blank of a new type of artificial board.

[0060] The pre-pressing process parameters are: hot pressing temperature 100-140°C, hot pressing time 10-60s, and hot pressing pressure 5-12MPa.

[0061] Step 150: hot pressing.

[0062] The rough blank of the new artificial board is hot-pressed under high temperature and high pressure to completely melt the polymer rubber powder into shape, and the finished new artificial board is obtained after cooling.

[0063] The hot pressing process parameters are: hot pressing temperature 160-240°C, hot pressing time 180-600s, and hot pressing pressure 8-20MPa.

[0064] The present application can prepare a new type of artificial board with a thickness of 5 to 40 mm. Taking the new type of artificial board with a thickness of 5 mm as an example, the performance is compared with the existing products. Comparison standard 1 refers to GB / T11718-2021 "Medium Density Fiberboard", and comparison standard 2 refers to GB / T 4897-2015 "Particleboard".

[0065] Among them, the physical and chemical properties are tested in accordance with GB / T 17657-2022 "Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels", and the moisture-proof performance is compared with the standard value under high humidity conditions.

[0066] The formaldehyde emission classification refers to the GB / T 39600-2021 standard "Classification of Formaldehyde Emission of Artificial Boards and Their Products", and the E1 limit value is 0.124 mg / m 3 The limit value of E0 is 0.05mg / m 3 , E NF The limit value is 0.025mg / m 3 .

[0067] The test results are shown in the following table:

[0068]

[0069] According to the above test results, compared with the existing particleboard and medium-density fiberboard standards, the new artificial board provided by the present invention meets the use requirements of the national standards in terms of static bending strength and water absorption expansion rate. After being immersed in 70°C water, the static bending strength loss is small, which can meet the use requirements under high humidity conditions. Among them, the static bending strength of Example 2 and the static bending strength after immersion treatment reach 300% of the standard value of particleboard, and the water absorption expansion rate under high humidity conditions is only 10% of the standard value, indicating that the embodiments of the present invention are excellent in mechanical strength and moisture resistance.

[0070] At the same time, the classification of formaldehyde emission is in line with the provisions of the standard for artificial boards, and the lowest can reach E NF Therefore, the new artificial board prepared by the present application scheme not only has excellent mechanical properties and no formaldehyde emission characteristics, but also has relatively stable quality in high temperature and high humidity environments, and has broad application prospects.

[0071] At present, the adhesives used in traditional wood-based panels mainly include urea-formaldehyde resin, phenol-formaldehyde resin, melamine-formaldehyde resin and their modified products (collectively referred to as "trialdehyde glue"). Most trialdehyde glues use formaldehyde and other raw materials, and usually produce incompletely reacted free formaldehyde during the production process. Even after the hot-pressing curing treatment of the wood-based panels, these free formaldehydes are still difficult to react completely, resulting in the slow release of formaldehyde during the production and use of the wood-based panels, posing long-term health risks to the living environment. In addition, traditional trialdehyde glues are generally thermosetting resins, and the glue layer formed after curing is often brittle. The cured resin contains hydrophilic free hydroxymethyl groups, which are easily combined with moisture. In a high humidity environment, it is easy to absorb water, swell, crack, and even cause deformation and distortion. This not only affects the structural strength of the board, but also leads to insufficient nail holding force, limiting the widespread application of wood-based panels.

[0072] The novel artificial board raw material provided by the present invention uses polymer powder as an adhesive, and utilizes its own thermoplasticity to complete the bonding of the boards. No organic solvent is added during the preparation and processing process, which solves the problem of formaldehyde release from the root, and realizes a green and healthy environmentally friendly artificial board. At the same time, the polyolefin material itself is a non-polar hydrophobic material, which can enter the interior of the wood fiber under high temperature and high pressure conditions and can well wrap the wood fiber, thereby improving the overall moisture-proof performance of the board.

[0073] The hot melt adhesive powder used in the present invention is maleic anhydride grafted polyolefin, and the maleic anhydride graft contains polar group aldehyde group and olefin non-polar chain segment, which has good compatibility with the base material polyolefin on the one hand, and can be chemically bonded with ~OH in the wood structure on the other hand, thereby improving the bonding strength between the polyolefin and the wood structure, and the polarity of the maleic anhydride group is similar to the polarity of the hydroxyl group in the wood, so that the adhesive has a strong affinity with the wood raw material. Therefore, the new artificial board has high strength and long-term stability, which can effectively avoid the decline of physical properties caused by aging of the adhesive, thereby extending the service life of the board.

[0074] Based on the description of the above specific embodiments, the high-strength new environmentally friendly artificial board and its preparation method provided by the present invention have the following advantages compared with the prior art:

[0075] First, the present invention uses polymer powder as an adhesive and utilizes its own thermoplasticity to complete the bonding of the boards. The preparation process is achieved through two-step hot pressing, and the process flow is simple. After the polymer powder is melted and bonded, the properties are stable and will not hydrolyze, and the stability of the board is enhanced. The polyolefin material itself exhibits plastic properties as a non-polar hydrophobic material. After hot pressing, a hydrophobic continuous phase is formed in the board, thereby improving the overall moisture-proof performance of the board. According to the heat resistance requirements of different boards, adding high-temperature resistant nylon 6 can improve the thermal stability of the board. Therefore, the new artificial board has good mechanical properties, stable quality under high temperature and high humidity environments, is not easy to expand after absorbing water, and exhibits excellent moisture-proof properties.

[0076] Second, the present invention uses maleic anhydride grafted polyolefin as hot melt adhesive, and no formaldehyde is added to the raw materials, which solves the problem of formaldehyde release from the root, so that the prepared artificial board reaches a higher environmental protection level. At the same time, the maleic anhydride group forms a chemical bond with the wood structure, which improves the bonding strength of the polyolefin and the wood structure, and further improves the strength and long-term stability of the board under the premise of green and environmentally friendly adhesive, thereby extending the service life of the board.

[0077] Finally, it should be noted that the terms "comprises", "includes" or any other variants thereof as used herein are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0078] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone should be aware that any structural changes made under the inspiration of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention.

Claims

1. A novel artificial board, comprising a core layer and two surface layers located on the outer surface of the core layer, wherein the thickness of the core layer is 60-80% of the thickness of the novel artificial board, and characterized in that: The core layer comprises the following raw materials in parts by weight: 20-40 parts of polymer rubber powder, 60-80 parts of wood raw materials, 1-4 parts of dispersant and 0.02-0.16 parts of antioxidant; The surface layer comprises the following raw materials in parts by weight: 10-20 parts of adhesive and 80-90 parts of wood raw materials.

2. The new artificial board according to claim 1 is characterized in that: The polymer adhesive powder is obtained by compounding polyolefin hot melt adhesive powder and polymer resin powder.

3. The new artificial board according to claim 2 is characterized in that: The high molecular polymer resin powder can be selected from one or a combination of powdered low-density polyethylene, high-density polyethylene, polypropylene, and nylon 6.

4. The new artificial board according to claim 2 is characterized in that: The polyolefin hot melt adhesive powder can be made of maleic anhydride grafted polyolefin.

5. The novel artificial board according to claim 1 is characterized in that: The wood raw material used in the surface layer is the same as the wood raw material used in the core layer.

6. The novel artificial board according to claim 1, characterized in that: The adhesive is urea-formaldehyde resin adhesive.

7. The novel artificial board according to claim 1 is characterized in that: The adhesive is diphenylmethane diisocyanate glue.

8. The novel artificial board according to claim 1, characterized in that: The adhesive is the same as the polymer rubber powder used in the core layer.

9. A method for preparing a novel artificial board, characterized in that: The method is used to prepare the novel wood-based panel according to any one of claims 1 to 8, and the method comprises the following steps: Drying the wood raw material to control the moisture content below 3wt%; Prepare the raw materials according to the composition ratio of the surface layer and the core layer, and evenly disperse them through a mixer to obtain the surface layer paving raw materials and the core layer paving raw materials; First, a layer of surface paving material is laid on the base, then a core layer of paving material is laid, and finally, a layer of surface paving material is laid on the core layer of paving material; Pre-press the laid board material to obtain a rough embryo of a new type of artificial board; The rough blank of the new artificial board is hot-pressed to make the polymer rubber powder completely melted and formed, and the finished new artificial board is obtained after cooling.

10. The method according to claim 9, characterized in that The pre-pressing process parameters are: hot pressing temperature 100-140°C, hot pressing time 10-60s, hot pressing pressure 5-12MPa; The hot pressing process parameters are: hot pressing temperature 160-240°C, hot pressing time 180-600s, and hot pressing pressure 8-20MPa.

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