Articles made from recycled foam and methods for their manufacture

Abstract

This discloses a multilayer article comprising a first layer having a first thermoplastic polyolefin; and wherein the first layer is in contact with a fourth layer having an olefin polymer having a peak melting point of 130 to 170°C; wherein the first layer has a lower modulus of elasticity than the fourth layer, the modulus of elasticity being measured according to ASTM D638; wherein the multilayer article is functional for use as a trim in the interior of a motor vehicle.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority over the preliminary US patent application with serial number 63 / 701,284, filed on September 30, 2024, the entire contents of which are hereby incorporated by reference. BACKGROUND

[0002] This disclosure relates to articles made from recycled foam and methods for their manufacture.

[0003] The recycling of polymeric materials is becoming increasingly important and economically valuable. Significant progress has been made in recycling thermoplastic polymers, but recycling cross-linked (also known as thermoset) materials remains a major challenge. Once a polymer is cross-linked, it does not remelt, and this property is a major obstacle to recycling cross-linked materials. Furthermore, cross-linked materials, particularly cross-linked foams, are often bonded to thermoplastics. Attempts to reuse these materials have typically involved separating the thermoplastic from the cross-linked foam—a time-consuming and labor-intensive process. Recycling a cross-linked material has previously involved various chemical methods to reduce the number of cross-links.These methods are generally expensive and can have negative environmental impacts. When applied to cross-linked foam, there is the additional problem of gas release from the foam cells, which can negatively affect the final product. Even if the cross-linked material is adequately processed for reuse, residual cross-linking agents can still negatively impact the final product.

[0004] There is still a need in the technology sector for a process for the reprocessing of cross-linked materials, especially foamed cross-linked material. SHORT DESCRIPTION

[0005] This discloses a multilayer article comprising a first layer having a first thermoplastic polyolefin; and wherein the first layer is in contact with a fourth layer having an olefin polymer having a peak melting point of 130 to 170°C; wherein the first layer has a lower modulus of elasticity than the fourth layer, the modulus of elasticity being measured according to ASTM D638; wherein the multilayer article is functional for use as a trim in the interior of a motor vehicle.

[0006] This discloses a method for producing a multilayer article, the method comprising: extruding a first layer, the first layer comprising a first thermoplastic polyolefin; unwinding a fourth layer from a feed roll, the fourth layer comprising an olefin polymer having a peak melting point of 130 to 170°C; the first layer having a lower modulus of elasticity than the fourth layer; and feeding the first layer and the fourth layer to a roll gap in a rolling mill, the first layer and the fourth layer being laminated to form a multilayer article.

[0007] This also discloses a method for recycling a multi-layered object, wherein the method comprises: shredding a multi-layered object (A) comprising: a) a first layer comprising a first thermoplastic polyolefin; and b) a fourth layer comprising an olefin polymer with a peak melting point of 130 to 170°C; or comminution of a multilayered object (B) comprising: i) a first layer comprising a first thermoplastic polyolefin; ii) a second layer comprising a second thermoplastic polyolefin; iii) a third layer comprising a third thermoplastic polyolefin; and iv) a fourth layer comprising an olefin polymer having a peak melting point of 130-170°C; wherein the first thermoplastic polyolefin differs from the second thermoplastic polyolefin; and melt mixing of a powder of each comminuted multilayer article (A) or (B) with additional thermoplastic polyolefin in a melt processor; wherein the powder of each comminuted multilayer article (A) or (B) comprises at least 50 wt.% of a thermoplastic polyolefin. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a schematic representation of an exemplary multi-layered object; Fig. Figure 2 is a simplified schematic representation of an exemplary procedure for producing the multilayered object; and Fig. Figure 3 is a schematic representation of an exemplary multi-layered object made of Fig. 1, wherein the multilayer object is bonded with a cross-linked polypropylene and a thermoplastic polyolefin substrate. DETAILED DESCRIPTION Definitions

[0008] Foam cells refer to the cellular structure in foams where gas bubbles are trapped in a solid matrix, creating a lightweight, porous structure.

[0009] Cross-linked polypropylene (sometimes referred to by the acronym XLPP) is widely used in applications such as automotive components, insulation materials, and foam products, especially where durability and stability under harsh conditions are required. It is a modified form of polypropylene (PP) in which covalent bonds, or "cross-links," are formed between the polymer chains. This cross-linking process improves the material's performance by making it more resistant to thermal, chemical, and mechanical stresses. It strengthens the material's structure, resulting in better resistance to heat deformation, impact, and cracking, and also improving durability under prolonged exposure to extreme conditions.Cross-linked polypropylene foam is a special material known for its use in industrial sectors where low weight, durability and thermal insulation properties are desired.

[0010] The term "olefin" refers to a class of hydrocarbons that contain at least one carbon-carbon double bond (C=C). Olefins are polymerized to produce polyolefins.

[0011] Polyolefins are sometimes referred to here as "olefin polymers". Detailed description

[0012] This document describes a multi-layered object that behaves like artificial leather and can be used as trim in a motor vehicle. The trim has a soft feel and can be used in the interior of motor vehicles either alone (in which case the resulting part is soft and flexible) or in combination with a rigid substrate material (in which case the resulting part is rigid). In one embodiment, the multi-layered object can comprise two or more layers, preferably three or more layers, and preferably four or more layers (a multi-layered object), each containing a thermoplastic polyolefin. The thermoplastic polyolefin is present in an amount of more than 50% by weight of each layer, based on the total weight of the layer. In one embodiment, the thermoplastic polyolefin is present in an amount of more than 50% by weight, preferably more than 55% by weight.-% and preferably more than 60% by weight, based on the total weight of the multi-layered item, are present.

[0013] The polyolefins used in the individual layers can be thermoplastic or cross-linked (sometimes also referred to as thermosets). In one embodiment, the polyolefins used in each layer are thermoplastics. This allows for easy recycling of the multilayered object. Since each layer contains a polyolefin, the multilayered object can be advantageously recycled to a landfill for further use (during its life cycle or after its life cycle has ended) with minimal material loss.

[0014] This document also discloses a method for manufacturing the multilayer articles. In one embodiment, a first method for manufacturing the multilayer article comprises co-extruding at least two or more layers, and preferably three or more layers (each comprising a polyolefin), to form a first laminate, which is then joined in a rolling mill to a fourth layer (hereinafter referred to as the carrier layer), also comprising a polyolefin, to form the multilayer article. In one embodiment, the fourth layer comprises an olefin polymer with a peak melting point of 130 to 170 °C.

[0015] A method for recycling the aforementioned multilayered article is also described here. In use, the multilayered article can optionally be arranged on a cross-linked polypropylene foam (sometimes referred to as XLPP foam) and / or a rigid thermoplastic polyolefin substrate (sometimes referred to as TPO substrate) (serving as a support) to form a rigid multilayered article. The cross-linked polypropylene foam and the rigid thermoplastic polyolefin substrate impart strength and geometric shape to the multilayered article (first layer 102 in combination with any of the remaining layers 104, 106, and 108) to form a three-dimensional object suitable for use in the interior of a motor vehicle.The rigid multilayered object thus has a soft surface (provided by layer 102), but possesses structural rigidity and can be load-bearing if required (due to the cross-linked polypropylene foam and / or the rigid thermoplastic polyolefin substrate). In one embodiment, the thermoplastic polyolefin is present in an amount of more than at least 50 wt.%, preferably more than 55 wt.%, and even more preferably more than 60 wt.%, based on the total weight of the rigid multilayered object.

[0016] The multilayer article or the rigid multilayer article can advantageously be recycled in its entirety to form regranulates, which can then be partially used to form the multilayer article disclosed herein. Since each layer of the rigid multilayer article contains polyolefins, it can advantageously be completely recycled in a single process without significant material loss in the form of waste. Furthermore, the absence of a substantial amount of cross-linked material in the multilayer article or the rigid multilayer article results in minimal phase separation between the various polymeric components added during recycling to aid the conversion of the recycled waste into a reusable thermoplastic polyolefin.The multilayered or rigid multilayered object is essentially free of polymers other than polyolefins, which minimizes phase separation, inhomogeneity, and incompatibility during reprocessing, thereby reducing waste and defects that would otherwise commonly occur. Only a minimal amount of material needs to be disposed of in a landfill. The recycled polyolefin can then be incorporated into each of the layers of the object. Fig. 1 and Fig. The 3 multi-layered articles shown are used.

[0017] Fig. Figure 1 is a schematic representation of an exemplary multilayered object 100, comprising several layers 102, 104, 106, and 108, at least one of which has a composition different from at least one other layer. In one embodiment, the multilayered object comprises at least one layer 102 (here referred to as the first layer 102) in contact with a layer 108 (here referred to as the fourth layer 108). In another embodiment, the object comprises at least two different layers—the first layer 102 and a second layer 104 arranged on the fourth layer 108—but may also comprise at least three layers: the first layer 102, the second layer 104, and a third layer 106 arranged on the fourth layer 108. The layers 104 and 106 may be optional (e.g., the multilayered object 100 may function without them).In a preferred embodiment, the multilayered object comprises at least four different layers: the first layer 102, the second layer 104, the third layer 106, and the fourth layer 108. Each of the four different layers—the first layer 102, the second layer 104, the third layer 106, and the fourth layer 108—contains polyolefins. In one embodiment, the first layer 102, the second layer 104, and the third layer 106 comprise thermoplastic elastomers. In another embodiment, the second layer 102 comprises a foamed thermoplastic elastomer.

[0018] As from Fig. As can be seen in Figure 1, the first layer 102 is in direct contact with the second layer 104, while the second layer 104, if present, is in direct contact on opposite sides with both the first layer 102 and the third layer 106. The third layer is in direct contact on opposite sides with the second layer 104 and the fourth layer 108. The fourth layer 108 is in direct contact with the third layer 106 on at least one of its sides. As can be seen from Fig. As can be seen in Figure 1, the first layer 102 and the fourth layer 108 form the outer layers of the multilayer object in one embodiment.

[0019] As will be explained in more detail below, each of the aforementioned layers (the first layer 102, the optional second layer 104, the optional third layer 106 and the fourth layer 108) can be arranged on a cross-linked polypropylene foam.

[0020] In one embodiment, each of the layers—the first layer 102, the second layer 104, and the third layer 106—can have the same or different chemical compositions, although they may have different physical structures. For example, the first layer 102 and the third layer 106 may have the same or different thicknesses but are both solid films (with essentially no porosity), while the second layer 104 is a foamed layer (with a porosity of more than 25% by volume, preferably more than 40% by volume, and particularly preferably more than 50% by volume) that may have a different thickness than the first layer 102 or the third layer 106. All of these features are explained below.

[0021] In one embodiment, the first layer 102 and the optional third layer 106 have a higher modulus of elasticity than the modulus of elasticity of the second layer 104 (determined according to ASTM D638), which comprises a foam. The modulus of elasticity of the fourth layer 108 is higher than that of the first layer 102, the second layer 104, and the third layer 106.

[0022] The first layer 102 can have the same or a different composition than the third layer 106. The third layer 106 can be optional. Layers 102 and 106 are elastomers (each has a modulus of elasticity from 0.01 megapascals (MPa) to less than 100 MPa, preferably less than 10 MPa, determined according to ASTM D638) and can each comprise a thermoplastic elastomer. In one embodiment, the first layer 102 can comprise a first thermoplastic elastomer, while the third layer 106 can comprise a third thermoplastic elastomer. In one embodiment, the first thermoplastic elastomer can have the same chemical composition as the third thermoplastic elastomer. In another embodiment, the first thermoplastic elastomer can have a different chemical composition than the third thermoplastic elastomer.

[0023] The first thermoplastic elastomer comprises a polypropylene-based elastomer, an ethylene-based elastomer, a polypropylene, and a filler. In one embodiment, the filler may be optional. The first layer 102 and the third layer 106 each contain at least 50 wt.% of a thermoplastic olefin polymer and are both in the form of rigid films that exhibit no significant porosity. The two layers 102 and 106 comprise flexible films that preferably have a soft feel.

[0024] As used here, the term "propylene-based elastomer" refers to a polymer containing more than 50 mol percent polymerized propylene monomer (based on the total amount of polymerizable monomers) and at least one comonomer.

[0025] In the embodiments described herein, the propylene-based elastomer is a propylene copolymer or a combination of a polypropylene homopolymer with a polypropylene copolymer. In some embodiments, the propylene-based elastomer is a propylene / olefin copolymer. The polypropylene homopolymer may be isotactic, atactic, or syndiotactic. In some embodiments, the propylene-based elastomer is an isotactic polypropylene homopolymer.

[0026] The propylene / olefin copolymer can be a statistical or block copolymer. The propylene / olefin copolymer comprises more than or equal to 100 percent, for example, at least 70 percent, at least 80 percent, at least 90 percent, at least 92 percent, or at least 95 percent, by weight, of units derived from propylene; and (b) less than 30 percent, for example, less than 25 percent, less than 20 percent, less than 10 percent, less than 8 percent, or less than 5 percent, by weight, of units derived from one or more alpha-olefin comonomers. In further embodiments, the propylene-based elastomer can be a combination of one or more propylene homopolymers, one or more propylene copolymers, or a combination of one or more propylene homopolymers and one or more propylene copolymers.

[0027] In embodiments described herein, in which the propylene-based elastomer comprises at least one alpha-olefin comonomer, the alpha-olefin comonomers have no more than 20 carbon atoms. For example, the alpha-olefin comonomers may have 3 to 10 carbon atoms or 3 to 8 carbon atoms. Examples of alpha-olefin comonomers include, but are not limited to, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene. The one or more alpha-olefin comonomers may, for example, be selected from the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene, or alternatively from the group consisting of ethylene. In the embodiments described here, the propylene-based elastomer may or may not be a homopolymer, copolymer or interpolymer.

[0028] The propylene-based elastomer can be produced using any polymerization method for propylene and, optionally, a comonomer. For example, gas-phase, bulk, slurry-phase, solution polymerization, or any combination thereof can be used. The polymerization can be a one-step, two-step, or multi-step process carried out in at least one polymerization reactor. For two-step or multi-step processes, various combinations can be used, such as gas-gas phase, slurry-slurry-phase, or slurry-gas phase processes. Suitable catalysts can be Ziegler-Natta catalysts, single-site catalysts (metallocene or with restricted geometry), or non-metallocene, metal-centered heteroaryl ligand catalysts, or combinations thereof.

[0029] The propylene-based elastomer can be used in the first layer 102 or the third layer 106 in an amount of 50 to 70 wt.%, preferably 55 to 65 wt.%, based on the total weight of the first layer 102 or the third layer 106, respectively.

[0030] In addition to the propylene-based elastomer, the first layer 102 or the third layer 106 comprises an ethylene-based elastomer. The ethylene-based elastomer comprises (a) less than or equal to 100 percent, for example, at least 70 percent, or at least 80 percent, or at least 90 percent, or at least 92 percent, or at least 95 percent, by weight, of units derived from ethylene; and (b) less than 30 percent, for example, less than 25 percent, or less than 20 percent, or less than 10 percent, or less than 8 percent, or less than 5 percent, by weight, of units derived from one or more alpha-olefin comonomers. The term "ethylene-based elastomer" as used herein refers to a polymer containing more than 50 mol percent polymerized ethylene monomer (based on the total amount of polymerizable monomers) and may optionally contain at least one comonomer.

[0031] In the embodiments described here, in which the ethylene-based elastomer contains at least one alpha-olefin comonomer, the alpha-olefin comonomers have no more than 20 carbon atoms. For example, the alpha-olefin comonomers may have 3 to 10 carbon atoms or 3 to 8 carbon atoms. Examples of alpha-olefin comonomers include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene. The one or more alpha-olefin comonomers may, for example, be selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene, or alternatively from the group consisting of 1-hexene and 1-octene. In the embodiments described here, the ethylene-based elastomer may or may not be a homopolymer, copolymer or interpolymer.

[0032] The ethylene-based elastomer can be produced by gas-phase, solution-phase, or slurry polymerization processes, or any combination thereof, using any type of reactor or reactor configuration known in the art, e.g., fluidized bed gas-phase reactors, loop reactors, stirred tank reactors, batch reactors in parallel or series, and / or any combination thereof. In some embodiments, gas or solution reactors are used. The catalysts used to produce the ethylene-based elastomer described herein can be Ziegler-Natta catalysts, metallocene catalysts, catalysts with restricted geometry, single-site catalysts, or combinations thereof.For example, the ethylene-based elastomer can be an LLDPE, such as a znLLDPE, which denotes linear polyethylene produced using Ziegler-Natta catalysts, a uLLDPE or “ultralinear low-density polyethylene”, which can include linear polyethylenes produced using Ziegler-Natta catalysts, or an mLLDPE, which refers to LLDPE produced using metallocene or restricted geometry catalyzed polyethylene.

[0033] The ethylene-based elastomer can be used in the first layer 102 or the third layer 106 in an amount of 10 to 30 wt.%, preferably 15 to 25 wt.%, based on the total weight of the first layer 102 or the third layer 106, respectively.

[0034] The first layer 102 and the third layer 106 further comprise a polypropylene homopolymer. It should be noted that this polypropylene homopolymer is present in addition to any polypropylene homopolymer that may be part of the polypropylene-based elastomer described above. The polypropylene homopolymer may be isotactic, atactic, or syndiotactic. In some embodiments, the polypropylene homopolymer is an isotactic polypropylene homopolymer. The polypropylene homopolymer may also contain small amounts of a statistical copolymer polypropylene (which is a copolymer of propylene with ethylene or an alpha-olefin comonomer with 3 to 20 carbon atoms), injection-molded polypropylene, or high-melt polypropylene. The alpha-olefin comonomers with 3 to 20 carbon atoms have already been listed above and are not repeated here for the sake of brevity.In one embodiment, polypropylene with high melt strength is produced using polypropylene with long-chain branching. In one embodiment, the long-chain branching can be produced by electron beam irradiation, reactive compounding, or a combination thereof.

[0035] The polypropylene homopolymer can be used in the first layer 102 or the third layer 106 in an amount of 5 to 25 wt.%, preferably 10 to 20 wt.%, based on the total weight of the first layer 102 or the third layer 106.

[0036] The first layer 102 and / or the third layer 106 may also contain fillers and additives. A “filler” includes reinforcing fillers such as glass fibers and beads, carbon fibers, carbon nanotubes, carbon black, polymer fibers (e.g., polyester fibers, polyaramid fibers, polyimide fibers, polyetherimide fibers, or the like, or a combination thereof), clay, or the like, or a combination thereof. These fillers may be in the form of nanoparticles (with an average particle size of less than 100 nanometers) or micrometer-sized particles (with an average particle size of more than or equal to 100 nanometers). The fillers may have a unimodal particle size distribution or a multimodal (e.g., bimodal, trimodal, etc.) particle size distribution.

[0037] Furthermore, the first layer 102 and / or the third layer 106 may contain additives such as antistatic agents, color enhancers, dyes, lubricants, fillers such as TiO2 or CaCO3, opacifiers, nucleating agents, processing aids, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, antiblocking agents, lubricants, tackifiers, flame retardants, antimicrobial agents, odor reducers, antifungal agents and combinations thereof.

[0038] The one or more fillers and additives may be present in the first layer 102 and / or the third layer 106 in quantities commonly used in the industry to fulfill their intended purpose. In some examples, the one or more additives are present in quantities of 0 to 10 wt.%, 1 to 5 wt.%, or 1.5 to 4 wt.% of the total weight of the first layer 102 and / or the third layer 106.

[0039] As mentioned above, the first layer 102 can be arranged directly on the fourth layer 108 or alternatively on the second layer 104 and the third layer 106. If the first layer 102 is directly bonded to the fourth layer 108, the first layer has a thickness of 0.10 to 0.7 millimeters, preferably 0.2 to 0.6 millimeters.

[0040] When the first layer 102 is bonded to the second layer 104 and the third layer 106, the first layer 102 and the optional third layer 106 can have the same thickness, or one layer can have a different thickness than the other. In one embodiment, the first layer 102 has a thickness of 0.05 to 0.35 millimeters. In another embodiment, the third layer 106 has a thickness of 0.05 to 0.35 millimeters.

[0041] The second layer 104 is preferably a foamed layer comprising a second thermoplastic elastomer. The second thermoplastic elastomer may be identical to or different from the first thermoplastic elastomer (used in the first layer 102) or the third thermoplastic elastomer (used in the third layer 106). The second layer 104 is preferably a foamed layer having the same composition as the first layer 102 and the third layer 106, except that it contains (before foaming) a blowing agent and / or a nucleating agent that promotes cell formation during the foaming process. Residues of the blowing agent and the nucleating agent may be present in the foam after foaming. The foam may be an open-cell foam, a closed-cell foam, or a foam comprising both closed and open cells.In one embodiment, the foam is preferably a closed-cell foam. Depending on the application, the foam can be a soft, flexible foam or a rigid foam. In a preferred embodiment, the foam is a soft, flexible foam containing a thermoplastic polyolefin. The foam layer 104 is not cross-linked.

[0042] The propellants can be physical propellants, chemical propellants, or a combination thereof. In a preferred embodiment, the propellant is a chemical propellant. Both types of propellants are described below.

[0043] Physical blowing agents typically undergo phase separation from the organic polymer (in which they are dissolved) when they experience a change in environmental conditions to produce the foam, while chemical blowing agents are those that undergo a reaction or decomposition when they experience a change in environmental conditions to release a gas that leads to the formation of the foam.

[0044] A blowing agent is a substance capable of creating a cellular structure through a foaming process in various materials undergoing curing or phase transitions, such as organic polymers. They are typically used when the material to be foamed (e.g., the organic polymer) is in a liquid or molten state. The cellular structure within the polymer reduces its density while simultaneously increasing the relative stiffness of the original organic polymer. Blowing agents or related mechanisms for creating pores in a matrix that generate cellular materials are classified as follows: Physical blowing agents include chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrocarbons (e.g., pentane, butane, isopentane, cyclopentane, or the like), and liquid or supercritical carbon dioxide. The bubble / foam formation process is irreversible and endothermic, meaning it requires heat (e.g., from a melting process or chemical exothermicity due to cross-linking) or a pressure change to vaporize the liquid blowing agent.

[0045] Chemical blowing agents include azodicarbonamide, hydrazine, and other nitrogen-based organic polymers for thermoplastic and elastomeric polymer foams, as well as sodium bicarbonate for other thermoplastic polymer foams. Gaseous products and other byproducts are formed through a chemical reaction of the blowing agent, which is promoted by the heat of the foaming process or the exothermic heat of a reacting polymer. Since the foaming reaction proceeds to form low-molecular-weight compounds that act as blowing gases, additional exothermic heat is also released.

[0046] Mixed physical / chemical blowing agents can also be used to produce foamed organic polymers. Here, both the chemical and physical blowing agents are used together to balance each other with regard to the heat energy released and absorbed, thereby minimizing the temperature rise in the organic polymer and preventing thermal degradation.

[0047] Examples of suitable physical propellants include methyl fluoride, methyl chloride, difluoromethane, methylene chloride, perfluoromethane or the like; hydrocarbons such as acetylene, ammonia, butane, butene, isobutane, isobutylene, propane, dimethylpropane, ethane, methane, trimethylamine, pentane, cyclopentane, hexane, propane, propylene, alcohols, ethers, ketones or the like, or a combination thereof.

[0048] In another embodiment, a thermally expandable microsphere can be used as the propellant.

[0049] The microsphere consists of a gas-tight polymer shell (e.g., polyacrylonitrile or polyvinylidene chloride) encapsulating a (cyclo)aliphatic hydrocarbon (e.g., liquid isobutene). When the thermally expandable microspheres are exposed to temperatures of approximately 50°C to 200°C, the polymer shell softens and the (cyclo)aliphatic hydrocarbon expands, promoting an increase in the microsphere's volume. In the expanded state, the microspheres have a diameter 3.5 to 4 times larger than their original diameter, so their expanded volume is consequently about 50 to 60 times greater than their original volume in the unexpanded state. EXPANCEL is an example of such thermally expandable microspheres. ®DU microspheres, distributed by Nouryon Industries.

[0050] The blowing agent is present in the second layer before foaming in an amount of 1 to 5 wt.%, preferably 1.25 to 2.0 wt.%, based on the total weight of the second layer 104. The residual blowing agent (the amount of residual agent in the foam after foaming) is 0.01 to 2 wt.%, based on the total weight of the foamed second layer 104.

[0051] The second layer 104 may also contain a nucleating agent. Nucleating agents are typically used in conjunction with chemical blowing agents. They promote the nucleation of cells, which eventually grow in size through binodal segregation to form the foam. Nucleating agents for polymer foaming are additives that promote the formation of gas bubbles during the foaming process, resulting in a more uniform cell structure and improved mechanical properties. These agents help control the size, distribution, and density of the foam cells, thereby enhancing the final properties of the polymer foam. Examples of nucleating agents include talc, calcium carbonate, silicon dioxide, sodium bicarbonate, organic salts, clay, titanium dioxide, metal oxides (e.g., zinc oxide, magnesium oxide, or the like), carbon dioxide gas, nitrogen gas, or the like, or a combination thereof.

[0052] The nucleating agent can optionally be present in the second layer 104 prior to foaming in an amount of 0.5 to 2.5 wt.%, preferably 1 to 2 wt.%, based on the total weight of the second layer 104.

[0053] In one embodiment, the foam can first be produced by mixing the polymer with a suitable blowing agent, such that the polymer-blowing agent combination exists in a single phase. The polymer-blowing agent combination is maintained at a pressure and temperature effective in keeping the combination in a single phase until it is ready for use. If desired, the combination is pumped through a nozzle or poured into the cavities, and the pressure and / or temperature is changed to promote binodal segregation, which leads to nucleation and cell growth in the polymer to form the foam. When the pressure and / or temperature in the cavities is changed, the blowing agent nucleates and grows in the polymer matrix, resulting in the formation of a polymer foam.

[0054] Alternatively, when using a chemical blowing agent, the polymer-blowing agent combination is maintained at a pressure and temperature effective in keeping the combination in a single phase until it is ready for use. If desired, the combination is pumped through a nozzle or poured into the cavities, and the pressure and / or temperature is changed to promote the separation of the blowing agent, releasing a gas that leads to nucleation and cell growth in the polymer to form the foam.

[0055] In one embodiment, the second layer 104 has a thickness of 0.15 to 0.90 millimeters.

[0056] The second layer 104 has a porosity of 60 to 90 volume percent, preferably 70 to 88 volume percent, and particularly preferably 75 to 85 volume percent. The pores have an average cell size of between 15 and 100 micrometers.

[0057] In one embodiment, the fourth layer 108 comprises an olefin polymer with a peak melting point of 130 to 170 °C. The fourth layer 108 (sometimes referred to as the support layer) generally comprises a polypropylene homopolymer or a polypropylene copolymer. Both polypropylene homopolymers and polypropylene copolymers have already been described in detail above and will not be discussed again for the sake of brevity.

[0058] The fourth layer 108 can be in the form of a solid film or in the form of a woven or nonwoven textile. In one embodiment, the fourth layer 108 is in the form of a circular knit fabric. A circular knit fabric is a type of fabric produced on a circular knitting machine rather than a flatbed knitting machine. In circular knitting, the fabric is knitted in a continuous tube as the machine's needles move up and down while also rotating. The fabric tube is then cut lengthwise. It can be washed / finished on a frame. The result is a seamless, stretchable fabric that can be used for a wide variety of applications, particularly for garments requiring comfort and flexibility. The fourth layer 108 typically has a higher modulus of elasticity than the first layer 102.

[0059] In one embodiment, where the first layer 102 is directly connected to the fourth layer 108, the fourth layer has a thickness of 0.3 to 1.2 millimeters, preferably 0.5 to 0.9 millimeters. If, on the other hand, the first layer is connected to the fourth layer via the second and third layers, the fourth layer has a thickness of 0.1 to 0.5 millimeters, preferably 0.15 to 0.45 millimeters.

[0060] In one embodiment, in one method of manufacturing the multilayer object 100, the composition for the first layer 102 and optionally the second layer 104 and the third layer 106 is arranged in three separate extruders 202, 204 and 206, as shown in Fig. 2 can be seen. Fig. Figure 2 is a simplified schematic representation of an exemplary manufacturing plant used to produce the multilayer object 100. The first layer 102 and the third layer 106 can be extruded as solid films, while the second layer 104 can be extruded as a foam.

[0061] The first layer 102, and optionally layers 104 and 106, can be co-extruded together with the fourth layer 108 into the "roll gap" of a rolling mill. The "roll gap" (the distance between the opposing rolls 210 and 212) is adjusted so that the desired pressure is exerted on the first to fourth layers—102, optionally 104, optionally 106, and 108—to form the multilayered object. The fourth layer 108 can be unwound from a feed roll 208 and fed into the roll gap. Alternatively, it can be co-extruded and fed into the gap to be laminated to form the multilayered object 100. As shown in the Fig. 1 and Fig. As can be seen in Figure 3, the first layer and the fourth layer each lie on an outer surface of the second layer and the third layer, respectively. The inner surface of the second layer touches an inner surface of the third layer.

[0062] The rolling mill can be a 2-roll mill or a 3-roll mill. 3-roll mills are preferred. During the rolling process, the pressure exerted on the various layers should be sufficient to enable lamination and create adequate adhesion between the different layers (102 to 108) without compromising the quality of the second layer 104 (the foam layer). Excessive pressure in the roll gap could reduce the porosity of the foam layer, which is undesirable.

[0063] In one embodiment, the multilayered object, comprising two to four layers, is then applied to a cross-linked polypropylene foam (sometimes referred to as XLPP foam) and / or a rigid thermoplastic polyolefin substrate (sometimes referred to as TPO substrate) (serving as a support) to form a rigid multilayered object. The cross-linked polypropylene layer can be a foam or, alternatively, a solid, non-porous layer. Fig. Figure 3 shows the multilayer object 100 which is combined with a cross-linked polypropylene 302 and a rigid thermoplastic polyolefin substrate 304 to form the rigid multilayer object 400.

[0064] In one embodiment, the joining of the multilayer article 100 with the layers of cross-linked polypropylene 302 and the rigid thermoplastic polyolefin substrate 304 can be carried out by a process comprising cutting, sewing, and wrapping. When the joining of the multilayer article 100 with the layers of cross-linked polypropylene 302 and the rigid thermoplastic polyolefin substrate 304 is carried out by a process comprising cutting, sewing, and wrapping, the layer of cross-linked polypropylene 302 has a thickness of 1.0 to 1.5 millimeters, preferably 1.1 to 1.4 millimeters, while the rigid thermoplastic polyolefin substrate 304 has a thickness of 2.0 to 3.0 millimeters, preferably 2.2 to 2.8 millimeters.

[0065] In another embodiment, the multilayer article 100 can be joined with the layers of cross-linked polypropylene 302 and the rigid thermoplastic polyolefin substrate 304 by a thermoforming process. When the multilayer article 100 is joined with the layers of cross-linked polypropylene 302 and the rigid thermoplastic polyolefin substrate 304 by a thermoforming process, the layer of cross-linked polypropylene 302 has a thickness of 2.0 to 3.0 millimeters, preferably 2.2 to 2.8 millimeters, while the rigid thermoplastic polyolefin substrate 304 has a thickness of 2.0 to 3.0 millimeters, preferably 2.2 to 2.8 millimeters. The film thickness and the thickness of the individual layers are measured perpendicular to the direction in which the extrudate exits the die of the extruder.

[0066] In one embodiment, the multilayered or rigid multilayered object can be recycled at the end of its life cycle. Since the entire multilayered object consists of a polyolefin, it can be recycled without any part having to be discarded due to incompatibility. As mentioned earlier, the presence of a thermoplastic polyolefin in an amount greater than 50% by weight, preferably greater than 55% by weight, and preferably greater than 60% by weight, based on the total weight of the multilayered or rigid multilayered object, makes the recycling process efficient and reduces waste due to incompatibility with materials added downstream in the recycling process.

[0067] In one embodiment, the multilayer or rigid multilayer object is optionally reduced in a comminution machine after use to a size that facilitates its introduction into the hopper of an extruder. The reduced object is then introduced, together with other thermoplastic polyolefins (such as those described above), into a melt processor to produce a new mixture of thermoplastic polyolefins, which is used in the Fig. 1 and Fig. The 3 described multi-layered objects can be reused.

[0068] Suitable melt processors include extruders, both single-screw and multi-screw. In addition to this requirement, and depending on the target application of the melt-processable material, the multilayer article (or rigid multilayer article) may require more rigorous processing to achieve the desired level of trapped gas in the melt-processable material. For example, for a film application, it may be necessary for the processed multilayer article (or rigid multilayer article) to have an average particle size that is less than or equal to the average cell size of the polymer foam (i.e., the second layer 104). Based on the average particle size of the processed material, tailored properties (e.g., hardness) are possible.A processed foam with a larger average particle size can produce a softer feel or a unique tactile / appearance due to the higher proportion of trapped gases remaining in the melt during processing. Conversely, an extremely demanding application may require the material of the multilayered (or rigid multilayered) item to have a very small average particle size to ensure that only negligible amounts of trapped gases are present during thermal processing. Processing includes any process that can achieve the appropriate particle size, such as shredding, milling, cryogenic milling, or a combination thereof. In addition to these exemplary processes, separation, solidification (i.e., compaction), or blending (e.g., mixing) may also be involved.(with an abrasive particle to aid size reduction).

[0069] The processed multilayer item (or rigid multilayer item) has a domain size under melt mixing conditions that is less than or equal to the processing spaces of the melt processor. The domain size is defined as the volume occupied by a discrete portion of the material of the processed multilayer item (or rigid multilayer item). This domain may or may not contain an trapped gas. The domain may or may not have a regular shape under melt mixing conditions. Furthermore, the domain may deform under melt mixing conditions to allow passage through the processing spaces. The processing spaces are defined as the spaces through which the melt-mixed material moves.In an extruder, the processing spaces would include, for example, the cylinder (especially the spaces between the screw(s) and the cylinder), a melt filter (if used), and holes in the die (if used). The domain size under melt mixing conditions is smaller than or equal to the smallest processing spaces of the melt processor to prevent clogging and blockages.

[0070] During recycling, thermoplastic materials and optional compatibility enhancers are mixed with the processed material of the multilayer (or rigid multilayer) item in the melt processor. The desired properties of the melt-processable materials ultimately depend on the specific material system. The additional materials should be readily melt-processable and, ideally, fully compatible with all existing materials. For example, a propylene-ethylene copolymer (e.g., a thermoplastic polyolefin) would be a suitable thermoplastic polymer to add to a system containing cross-linked polypropylene foam or cross-linked polypropylene foam bonded to a polyethylene skin.A compatibility enhancer is defined here as an additive that facilitates the distribution of the processed multilayer (or rigid multilayer) item throughout the matrix of the melt-processable polymeric material and stabilizes the morphology of the final product. The choice of a compatibility enhancer depends on the composition of the processed multilayer (or rigid multilayer) item and the composition of the final product matrix. Polymer compatibility enhancers include block / graft copolymers, polymers with polar side groups, and reactive functional polymers. Reactive compounds (reactive compatibility enhancers) that promote the in-situ formation of copolymers are also suitable. Examples of such reactive compatibility enhancers include unsaturated carboxylic acids and the like.

[0071] Examples of unsaturated carboxylic acids are maleic acid, fumaric acid, itaconic acid, methacrylic acid, crotonic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citraconic acid, or the like, or a combination thereof. Examples of derivatives of unsaturated carboxylic acids are maleic anhydride, citraconic anhydride, itaconic anhydride, malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, pimelic anhydride, suberic anhydride, azelaic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, or the like, or a combination thereof. Maleic anhydride is the preferred graft compound.

[0072] If the processed material includes a processed thermoplastic material (e.g., such as the multilayer article described here (or the rigid multilayer article)), no additional thermoplastic material may be desired, although additional thermoplastic material can be added. If an additional thermoplastic is included in the composition, it may be the same as or different from the processed thermoplastic material. For example, if the processed thermoplastic material is polyethylene, the additional thermoplastic material may be polyethylene, polypropylene, or a polyolefin copolymer. A compatibility enhancer, as described above, may also be added to the melt mixture composition.

[0073] During melt mixing, the design and / or conditions of the melt processor are chosen to minimize or eliminate the effects of any residual blowing agents, crosslinking agents, or a combination thereof. The melt mixture composition may also contain rheology modifiers to aid the extraction of volatile components during the melt mixing process. Modifying the rheology of the melt mixture composition can facilitate the removal of volatile components through the use of a vacuum. Rheology modifiers can also increase the viscosity and / or melt strength of the composition after the removal of the volatile components. Common rheology modifiers include commercially available plasticizers, which improve the flowability of a material.Certain classes of plasticizers include linear or branched phthalates, trimellites, adipates, polymers, and terephthalates. Processing conditions that affect the quality of the final material include, but are not limited to: screw design, screw speed, cylinder temperature profile, nozzle design, granule size, use of an underwater pelletizer, cutting tool design, and cutting speed, etc.

[0074] It is also envisaged that the processed polymer material can be melt-blended to form a granulated processed polymer material, and that the granulated processed polymer material can be melt-blended with another thermoplastic material. Similarly, a processed cross-linked polymer foam can be melt-blended with a first thermoplastic to form a granulated material, which is then melt-blended with a second thermoplastic to form the melt-processable material. Rheology modifiers and compatibility enhancers can be added at each melt-blending step.

[0075] In one embodiment, the recycled thermoplastic polyolefins can be incorporated into each of the layers of the material in the Fig. 1 and Fig. The multi-layered object described in section 3 can be reused.

[0076] In general, the invention may alternatively comprise, consist of, or consist substantially of all suitable components disclosed herein. The invention may additionally or alternatively be formulated such that it is free or substantially free of components, materials, ingredients, excipients, or species that are used in prior art compositions or that are otherwise not necessary to achieve the function and / or objectives of the present invention.

[0077] All ranges disclosed herein include the endpoints, and the endpoints are independently combinable with one another (e.g., the range "up to 25 wt.%, or, more precisely, 5 wt.% to 20 wt.%" includes the endpoints and all intermediate values ​​of the ranges from "5 wt.% to 25 wt.%," etc.). A "combination" includes mixtures, blends, alloys, reaction products, and the like. Furthermore, the terms "first," "second," and the like do not denote any order, quantity, or significance here, but are used to distinguish one element from another. The expressions "a," "an," and "the" do not imply any quantitative limitation here and are to be understood as including both the singular and the plural unless otherwise stated herein or clearly evident from the context.The suffix "(s)" / "en", as used here, is intended to encompass both the singular and plural forms of the term it modifies and thus includes one or more of these terms (e.g., "(the) foil(s) includes one or more foils"). References throughout the description to "a single embodiment", "another embodiment", "an embodiment", etc., mean that a particular element (e.g., a feature, structure, and / or property) described in connection with the embodiment is included in at least one embodiment described herein and may or may not be present in other embodiments. Furthermore, it should be understood that the described elements may be combined in any suitable manner in the various embodiments.

[0078] Although certain embodiments have been described, applicants or other persons skilled in the art may conceive of alternatives, modifications, variations, improvements, and substantial equivalents that are not currently foreseeable or even possible. Accordingly, the attached claims, as filed and as amended, are intended to encompass all such alternatives, modifications, variations, improvements, and substantial equivalents. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 701,284

[0001]

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