Open cell polymer foam composition with adjustable degree of curvature and method for producing same

Abstract

A polymeric composition is provided that includes a crosslinkable thermoplastic matrix, a crosslinking agent, a blowing agent, and at least one cell opener. A method of producing an open cell polymeric foam from the polymeric composition is also provided. The method includes heating a foamable precursor under positive pressure to a temperature above the decomposition temperature of the crosslinking agent and below the decomposition temperature of the chemical blowing agent to produce a primary foam. The method then includes heating the primary foam to a temperature above the decomposition temperature of the chemical blowing agent, and then allowing the primary foam to cool to a temperature below the softening temperature of the crosslinkable thermoplastic polymer to form an open cell polymeric foam. The open cell polymeric foam produced has an open cell content of at least 80% immediately after the step of allowing the primary foam to cool.

Description

[Background technology]

[0001] Polymer foams with open cell structure, such as polyurethane foams, are useful in a wide range of applications, including thermal insulation, sound and shock absorption, cushioning, furniture and packaging. For open cell foams based on thermoplastics, high open cell content is generally achieved by using mechanical deformation after making closed cell or partially closed cell foams. However, open cell foams made using mechanical deformation techniques generally have low flexural strength and poor thermal dimensional stability. Summary of the Invention [Problem to be solved by the invention]

[0002] This Summary is provided to introduce some concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. [Means for solving the problem]

[0003] In one aspect, embodiments described herein relate to a polymeric composition that includes a crosslinkable thermoplastic matrix, a crosslinking agent, a foaming agent, and at least one cell opener.

[0004] In another aspect, embodiments described herein relate to open cell polymer foams, including thermoplastic polymer foams. The foams have an open cell content of at least 80% and a cell density of 13 to 60 kg / m 3 It has a density in the range of

[0005] In yet another aspect, embodiments described herein relate to a method for adjusting the tortuosity of an open cell polymer foam, the method comprising the steps of selecting a target tortuosity range, selecting a polymer composition based on the target tortuosity range, blending the polymer compositions to form a foamable precursor, heating the foamable precursor under positive pressure to a temperature above the decomposition temperature of the crosslinking agent and below the decomposition temperature of the chemical blowing agent to produce a primary foam, heating the primary foam to a temperature above the decomposition temperature of the chemical blowing agent, and cooling the primary foam to a temperature below the softening temperature of the crosslinkable thermoplastic polymer to form an open cell polymer foam having a target tortuosity range. The polymer composition comprises a crosslinkable thermoplastic polymer, a crosslinking agent, a chemical blowing agent, and at least one cell opener.

[0006] In another aspect, the embodiments described herein relate to a method for producing an open cell polymer foam. The method includes heating a foamable precursor, the foamable precursor including a crosslinkable thermoplastic polymer, a crosslinking agent, a chemical blowing agent, and at least one cell opener. The step of heating the foamable precursor includes heating the foamable precursor under positive pressure to a temperature above the decomposition temperature of the crosslinking agent and below the decomposition temperature of the chemical blowing agent to produce a primary foam. The method then includes heating the primary foam to a temperature above the decomposition temperature of the chemical blowing agent, and then cooling the primary foam to a temperature below the softening temperature of the crosslinkable thermoplastic polymer to form an open cell polymer foam. The produced open cell polymer foam has an open cell content of at least 80% immediately after the step of cooling the primary foam.

[0007] In yet another aspect, embodiments described herein relate to a cell opener master batch composition comprising a carrier polymer and 10% to about 70% by weight of at least one cell opener.

[0008] Other aspects and advantages of the claimed subject matter will become apparent from the following description and the appended claims. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram of the foaming stage of a method according to one or more embodiments. [Diagram 2] FIG. 2 is a diagram of the foaming stage of the method according to one or more embodiments. [Diagram 3] FIG. 3 is a depiction of a diagram showing bending. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In one aspect, the embodiments described herein relate to open cell polymer foams with tunable tortuosity and high open cell content. Open cell polymer foams are particularly useful foams due to the interconnectivity of the cells that make up the foam. Foams according to the present disclosure have unique tunable properties because high open cell content can be achieved directly through the foam manufacturing process without mechanical deformation. High open cell content is achieved by a combination of a base polymer composition and a method for manufacturing the foam. Additionally, the embodiments relate to polymer compositions and cell opener masterbatches and the like that can be combined with the polymer compositions and other ingredients to arrive at the foams described herein.

[0011] [Polymer composition] One or more embodiments of the present disclosure relate to a polymeric composition that includes a crosslinkable thermoplastic matrix, a crosslinking agent, a blowing agent, and at least one cell opener.

[0012] The polymer composition according to the present disclosure comprises 100 parts by weight of a crosslinkable thermoplastic matrix suitable as a base for an open cell polymer foam. In certain embodiments, the crosslinkable thermoplastic matrix may comprise various types of polyolefin polymers. In one or more embodiments, the crosslinkable thermoplastic matrix may be selected from polyolefins, ethylene-based polymers, propylene-based polymers, and combinations thereof. In one or more embodiments, the crosslinkable thermoplastic matrix may be selected from the group consisting of low density polyethylene, high density polyethylene, linear low density polyethylene, copolymers of ethylene and one or more C3-C20 alpha olefins, polypropylene, ethylene vinyl acetate copolymers, ethylene methyl acrylate copolymers, ethylene butyl acrylate copolymers, ethylene-propylene copolymers, ethylene-propylene diene copolymers, thermoplastic ethylene elastomers, metallocene polymers, polyether block amide copolymers, polyvinylidene fluoride, copolyesters, polyolefin elastomers, vulcanized thermoplastic elastomers or styrene block copolymers, chlorinated derivatives thereof, and combinations thereof. In certain embodiments, the thermoplastic matrix is ​​selected from ethylene vinyl acetate copolymers, low density polyethylene, and combinations thereof. In some embodiments, the thermoplastic matrix may include polymers produced from petroleum-based monomers and / or bio-based monomers (such as ethylene derived from ethanol derived from sugar cane). Commercial examples of bio-based polymers include the "I'm Green™" line of bio-polyethylene and bio-ethylene vinyl acetate copolymers from Braskem SA.

[0013] In one or more embodiments, the thermoplastic matrix according to the present disclosure may include an ethylene vinyl acetate copolymer (EVA polymer) having various percentages of ethylene and vinyl acetate, in addition to one or more optional additional comonomers. For example, the thermoplastic matrix according to the present disclosure may include a vinyl acetate content in weight percent ranging from a lower limit selected from one of 5%, 8%, 12%, 15%, 20% by weight, and an upper limit selected from 25%, 30%, 35%, 40%, 60%, 75%, or 95% by weight, based on the weight of the ethylene vinyl acetate copolymer, as determined by ASTM D5594, where any lower limit may be paired with any upper limit. Furthermore, of this total amount of vinyl acetate, at least a portion of the vinyl acetate may be based on a renewable carbon source, if desired.

[0014] The thermoplastic matrix according to the present disclosure may include an EVA polymer, which exhibits a melt index, as determined by ASTM D1238 and measured at 190° C. with a load of 2.16 kg, that may range from a lower limit selected from one of 0.1 g / 10 min, 1 g / 10 min, 2 g / 10 min, 5 g / 10 min, 10 g / 10 min, 20 g / 10 min, and 50 g / 10 min, to an upper limit selected from one of 50 g / 10 min, 100 g / 10 min, 200 g / 10 min, 300 g / 10 min, or 400 g / 10 min, where any lower limit may be paired with any upper limit.

[0015] The thermoplastic matrix according to the present disclosure may include an EVA polymer, the density of which is 0.91 g / cm as determined by ASTM D792. 3 , 0.95g / cm 3 , 0.97g / cm 3 , or 1.1 g / cm 3 and 1.1 g / cm 3 , 1.5g / cm 3 , 1.9g / cm 3 , 1.21g / cm 3 , or 1.25 g / cm 3and any lower limit may be paired with any upper limit.

[0016] The polymer compositions described herein include a crosslinking agent suitable for crosslinking with the crosslinkable thermoplastic matrix. The crosslinking agent may be selected based on the type of crosslinkable thermoplastic matrix used. In one or more embodiments, the crosslinking agent may be a peroxide. In other embodiments, the crosslinking agent may be a silane. In one or more embodiments, the crosslinking agent may be 1,1-bis(tert-butylperoxyl)-3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, 2,2-bis(tert-butylperoxyl)butane, dicumyl peroxide, dieter amyl peroxide, dieter butyl peroxide, 1,2-bis(tert-butyl)-isopropylbenzene, 2,5-bis(tert-butylperoxy)-2-5-dimethylhexane, 2,5-dimethyl-2,5 di(tert-butylperoxy)hexyne-3, 1, 3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-tuylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl perbenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, t-butylcumyl peroxide, and combinations thereof.

[0017] Crosslinkers include benzoyl peroxide; dicumyl peroxide; di-tert-butyl peroxide; 0-Tert-amyl-0-2-ethylhexyl monoperoxycarbonate; tert-butyl cumyl peroxide; tert-butyl 3,5,5-trimethylhexanoate peroxide; tert-butyl peroxybenzoate; 2-ethylhexyl carbonate tert-butyl peroxide; 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane; 1,1-di(t butyl 4,4-di(tert-butylperoxide)valerate; di(2,4-dichlorobenzoyl)peroxide; di(4-methylbenzoyl)peroxide; di(tert-butylperoxyisopropyl)benzene peroxide and the like may also be included.

[0018] Crosslinkers include benzoyl peroxide, 2,5-di(cumylperoxy)-2,5-dimethylhexane, 2,5-di(cumylperoxy)-2,5-dimethylhexyne-3,4-methyl-4-(t-butylperoxy)-2-pentanol, butyl-peroxy-2-ethyl-hexanoate, tert-butyl peroxypivalate, tertiary butyl peroxyneodecanoate, t-butyl-peroxy-benzoate, t-butyl-peroxy-2-ethyl-hexanoate, 4-methyl-4-(t-amylperoxy)-2-pentanoate, and tert-butyl peroxypivalate. 4-Methyl-4-(cumylperoxy)-2-pentanol, 4-Methyl-4-(t-butylperoxy)-2-pentanone, 4-Methyl-4-(t-amylperoxy)-2-pentanone, 4-Methyl-4-(cumylperoxy)-2-pentanone, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-amylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(t-amylperoxy)hexyne-3, 2,5-di Methyl-2-t-butylperoxy-5-hydroperoxyhexane, 2,5-dimethyl-2-cumylperoxy-5-hydroperoxyhexane, 2,5-dimethyl-2-t-amylperoxy-5-hydroperoxyhexane, m / p-alpha,alpha-di[(t-butylperoxy)isopropyl]benzene, 1,3,5-tris(t-butylperoxyisopropyl)benzene, 1,3,5-tris(t-amylperoxyisopropyl)benzene, 1,3,5-tris(cumylperoxyisopropyl)benzene, di[1,3-dimethyl -3-(t-butylperoxy)butyl]carbonate, di[1,3-dimethyl-3-(t-amylperoxy)butyl]carbonate, di[1,3-dimethyl-3-(cumylperoxy)butyl]carbonate, di-t-amyl peroxide, t-amyl cumyl peroxide, t-butyl-isopropenyl cumyl peroxide, 2,4,6-tri(butylperoxy)-s-triazine, 1,3,5-tri[1-(t-butylperoxy)-1-methylethyl]benzene, 1,3,5-tri-[(t-butylperoxy)isopropyl]benzene, 1,3-Dimethyl-3-(t-butylperoxy)butanol, 1,3-Dimethyl-3-(t-amylperoxy)butanol, di(2-phenoxyethyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, dimyristylperoxydicarbonate, dibenzylperoxydicarbonate, di(isobomy)peroxydicarbonate, 3-cumylperoxy-1,3-dimethylbutylmethacrylate, 3-t-butylperoxy-1,3-dimethylbutylmethacrylate, 3-t-amylperoxy-1 ,3-Dimethylbutyl methacrylate, tri(1,3-dimethyl-3-t-butylperoxybutyloxy)vinylsilane, 1,3-dimethyl-3-(t-butylperoxy)butyl N-[1-{3-(1-methylethenyl)-phenyl}1-methylethyl]carbamate, 1,3-dimethyl-3-(t-amylperoxy)butyl N-[1-{3(1-methylethenyl)-phenyl}-1-methylethyl]carbamate, 1,3-dimethyl-3-(cumylperoxy))butyl N-[1-{3-(1-methylethenyl)-phenyl}-1-methyl Ethyl]carbamate, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-butylperoxy)cyclohexane, n-butyl 4,4-di(t-amylperoxy)valerate, ethyl 3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, 3,6,6,9,9-pentamethyl-3-ethoxycarbonyl(cabonyl)methyl-1,2,4,5-tetraoxacyclononane, n-butyl-4,4-bis(t-butylperoxy)valerate, ethyl-3, 3-Di(t-amylperoxy)butyrate, benzoyl peroxide, OO-t-butyl-O-hydrogen-monoperoxy-succinate, OO-t-amyl-O-hydrogen-monoperoxy-succinate, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane (or methyl ethyl ketone peroxide cyclic trimer), methyl ethyl ketone peroxide cyclic dimer, 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane, 2,5-dimethyl-2,5-Di(benzoylperoxy)hexane, t-butyl perbenzoate, t-butyl peroxyacetate, t-butyl peroxy-2-ethylhexanoate, t-amyl perbenzoate, t-amyl peroxyacetate, t-butyl peroxyisobutyrate, 3-hydroxy-1,1-dimethyl t-butylperoxy-2-ethylhexanoate, OO-t-amyl-O-hydrogen-monoperoxysuccinate, OO-t-butyl t-Butyl-O-hydrogen-monoperoxysuccinate, di-t-butyl diperoxyphthalate, t-butylperoxy(3,3,5-trimethylhexanoate), 1,4-bis(t-butylperoxycarbo)cyclohexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl-peroxy-(cis-3-carboxy)propionate, allyl 3-methyl-3-t-butylperoxybutyrate, OO-t-bu butyl-O-isopropyl monoperoxycarbonate, OO-t-butyl-O-(2-ethylhexyl) monoperoxycarbonate, 1,1,1-tris[2-(t-butylperoxycarbonyloxy)ethoxymethyl]propane, 1,1,1-tris[2-(t-amylperoxycarbonyloxy)ethoxymethyl]propane, 1,1,1-tris[2-(cumylperoxycarbonyloxy)ethoxymethyl]propane, OO-t -amyl-O-isopropyl monoperoxycarbonate, di(4-methylbenzoyl) peroxide, di(3-methylbenzoyl) peroxide, di(2-methylbenzoyl) peroxide, didecanoyl peroxide, dilauroyl peroxide, 2,4-dibromo-benzoyl peroxide, succinic acid peroxide, dibenzoyl peroxide, di(2,4-dichloro-benzoyl) peroxide, and combinations thereof.

[0019] In one or more embodiments, the crosslinker may be present in the polymer composition in an amount ranging from 0.1 to 4.0 phr (parts by weight per 100 parts by weight of the crosslinkable thermoplastic matrix). For example, the crosslinker may be present in an amount having a lower limit of one of 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.2, 1.4, 1.5, 1.7, and 2.0 phr and an upper limit of one of 2.2, 2.4, 2.5, 2.7, 3.0, 3.2, 3.5, 3.7, and 4.0, with any lower limit paired with any mathematically compatible upper limit.

[0020] The polymer composition of one or more embodiments includes one or more blowing agents. The blowing agent may include solid, liquid, or gas blowing agents. The physical blowing agents may include volatile organic solvents such as hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, isohexane, cyclohexane, alcohols such as ethanol and methanol, and gases such as nitrogen, carbon dioxide, carbon monoxide, hydrofluoroolefins (HFOs), hydrofluorocarbons (HFCs), and other physical blowing agents. The blowing agent may be a chemical blowing agent. In embodiments where the blowing agent is a chemical blowing agent, the chemical blowing agent may be selected from the group consisting of azodicarbonamide, azobisisobutyronitrile, oxydibenzenesulfonylhydrazide, 5-phenyltetrazole, sodium bicarbonate, citric acid, citrate, urea, N,N'dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosoterephthalamidotrinitrodimethyl(timethyl)triamine, 4,4'-oxybis(benzenesulfonylhydrazide), paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, allylbis(sulfonylhydrazide), p-toluylenesulfonylsemicarbazide, 4,4'-oxybis(benzenesulfonylsemicarbazide), trichloromonofluoromethane, dichloromonofluoromethane, 5-morpholyl-1,2,3,4-thiatriazole, and combinations thereof. In one or more embodiments, the polymeric composition may include a physical blowing agent and a chemical blowing agent.

[0021] In one or more embodiments, the blowing agent is included in the polymer composition in an amount ranging from 1 to 60 phr. For example, the blowing agent may be included in an amount having a lower limit of one of 1, 2.5, 5, 10, 15, 20, 25, and 30 phr and an upper limit of one of 35, 40, 45, 50, 55, and 60 phr, any lower limit paired with any mathematically compatible upper limit.

[0022] The polymer composition according to the present disclosure also includes at least one cell opener. The cell opener is useful for opening cells during foam production. Thus, the cell opener contributes to achieving a foam with adjustable tortuosity. Different types of cell openers may be selected based on the desired physical properties of the foam produced from the polymer composition. Types of cell openers include surface tension modifiers, rheology modifiers, and inorganic compounds. The cell openers may be used alone or in combination.

[0023] In one or more embodiments, the cell opener includes one or more surface tension modifiers. The surface tension modifiers may be polymer matrices blended with the crosslinkable polymer matrices described above. Examples of types of surface tension modifiers include styrenic materials, polyolefins, polyamides, acrylate-based polymers, polyesters, biodegradable products, rubbers, and thermoplastic elastomers. In certain embodiments, the surface tension modifier may be selected from the group consisting of polystyrene, styrene acrylonitrile, polypropylene, polyolefins having a weight average molecular weight higher than the crosslinkable matrix, polymethyl methacrylate, polyethylene terephthalate, glycol modified polyethylene terephthalate, polyhydroxyalkanoates (PHAs), polylactic acid, starch, polyvinyl alcohol, natural rubber, ethylene-propylene-diene monomer (EPDM), polydimethylsiloxane (PDMS), acrylonitrile butadiene rubber (NBR), polyether block amides (PEBA), thermoplastic polyolefin elastomers (TPO), styrene block copolymers (TPS), thermoplastic polyurethane elastomers (TPU), thermoplastic vulcanizates (also called crosslinked thermoplastic elastomers), and thermoplastic copolyester elastomers.

[0024] In one or more embodiments, the surface tension modifier is present in an amount ranging from 1 to 50 phr. For example, the surface tension modifier may be included in an amount having a lower limit of one of 1, 5, 10, 15, 20, and 25 phr and an upper limit of one of 25, 30, 35, 40, 45, and 50 phr, any lower limit may be paired with any mathematically compatible upper limit.

[0025] In one or more embodiments, the cell opener includes one or more rheology modifiers. Rheology modifiers are compounds that disrupt the crosslinking process and change the rheology of the composition. In one or more specific embodiments, the rheology modifier can be a primary or secondary amide or bisamide, or an amide or bisamide formed from a primary or secondary fatty acid. For example, the rheology modifier can be erucamide, oleamide, docosanamide, stearamide, ethylene bis-oleamide, stearyl erucamide, or oleyl palmitamide. In one or more embodiments, the rheology modifier is present in an amount ranging from 0.05 to 7.0 phr. For example, the rheology modifier may be included in an amount having a lower limit of one of 0.05, 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 and an upper limit of one of 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, and 7.0, any lower limit may be paired with any upper limit.

[0026] In one or more embodiments, the cell opener includes one or more inorganic compounds. The inorganic compounds facilitate the rupture of the cell walls during foaming. The inorganic compounds may be any suitable inorganic compounds in granular or particulate form. Examples of types of inorganic compounds include, but are not limited to, talc, carbonates such as calcium carbonate and sodium carbonate, silicates, mica, silica, hydroxides such as metal hydroxides (e.g., aluminum hydroxide and magnesium hydroxide), and clays such as montmorollonite and sepiolite. The inorganic materials may have particles with particle sizes ranging from nanometer-scale to micrometer-scale.

[0027] In one or more embodiments, the inorganic compound is present in an amount ranging from 1 to 50 phr. For example, the inorganic compound may be included in an amount having a lower limit of one of 1, 5, 10, 15, 20, and 25 phr and an upper limit of one of 30, 35, 40, 45, and 50 phr, any lower limit being paired with any upper limit.

[0028] The polymer composition according to the present disclosure may include one or more foaming accelerators (also called kickers) that accelerate or initiate the action of the foaming agent by lowering the associated activation temperature. For example, foaming accelerators may be used when the selected foaming agent reacts or decomposes at temperatures above 140°C, such as 220°C or higher, and the surrounding polymer is decomposed when heated to the activation temperature. The foaming accelerator may include any suitable foaming accelerator capable of activating the selected foaming agent. In one or more embodiments, suitable foaming accelerators may include cadmium salts, cadmium-zinc salts, lead salts, lead-zinc salts, barium salts, barium-zinc (Ba-Zn) salts, zinc oxide, titanium dioxide, triethanolamine, diphenylamine, sulfonated aromatic acids and their salts, and the like.

[0029] In one or more embodiments, the foam accelerator may be included in an amount ranging from 0.01 to 4.00 phr. For example, the foam accelerator may be included in an amount having a lower limit of one of 0.01, 0.05, 0.10, 0.50, 1.00, 1.20, 1.50, 1.70, and 2.00 phr and an upper limit of one of 2.20, 2.40, 2.60, 2.80, 3.00, 3.20, 3.40, 3.60, 3.80, and 4.00 phr, where any lower limit may be paired with any mathematically compatible upper limit.

[0030] The polymer compositions disclosed herein may include processing aids. In one or more embodiments, the processing aids may include stearic acid, glycerol monostearate (GMS), metal stearates such as zinc stearate or magnesium stearate, waxes such as paraffin, and polyolefin waxes.

[0031] In one or more embodiments, the processing aid may be included in an amount ranging from 0.05 to 2.0 phr. For example, the processing aid may be included in an amount having a lower limit of one of 0.05, 0.1, 0.2, 0.5, 0.7, and 1.0 phr and an upper limit of one of 1.0, 1.2, 1.5, 1.7, and 2.0 phr, any lower limit may be paired with any mathematically compatible upper limit.

[0032] The polymeric composition of the present disclosure may include a cell enlarger. The cell enlarger may be a polymer having a linear chain structure that has the same properties as the crosslinkable thermoplastic matrix. Regardless of the molecular structure (branched or linear) of the crosslinkable thermoplastic matrix, the cell enlarger is a polymer that exhibits a linear molecular chain. In one or more specific embodiments, the cell enlarger may be selected from the group consisting of linear low density polyethylene, linear polypropylene, high density polyethylene, and combinations thereof.

[0033] In one or more embodiments, the cell enlarger may be included in an amount ranging from 1 to 30 phr. For example, the cell enlarger may be included in an amount having a lower limit of one of 1, 2, 5, 10, 12, and 15 phr and an upper limit of one of 15, 22, 25, 27, and 30 phr, any lower limit being paired with any mathematically compatible upper limit.

[0034] The polymer composition according to the present disclosure may include one or more physical property modifiers such as fillers and additives that modify various physical and chemical properties when added to the polymer composition during blending, including one or more polymer additives such as lubricants, antistatic agents, clarifiers, nucleating agents, β-nucleating agents, antioxidants, compatibilizers, antacids, light stabilizers such as HALS, IR absorbers, whitening agents, inorganic fillers, organic and / or inorganic dyes, antiblocking agents, flame retardants, plasticizers, fungicides, adhesion promoters, metal oxides, mineral fillers, lubricants, oils, anti-oxidants, antiozonants, accelerators, pigments, colorants, and vulcanizing agents.

[0035] The polymer compositions according to the present disclosure may contain one or more inorganic fillers as physical property modifiers such as talc, glass fiber, marble powder, cement powder, clay, carbon black, graphite, feldspar, silica or glass, fumed silica, silicates, calcium silicate, silicic acid powder, glass microspheres, mica, metal oxide particles and nanoparticles such as magnesium oxide, antimony oxide, zinc oxide, inorganic salt particles and nanoparticles such as barium sulfate, wollastonite, alumina, aluminum silicate, titanium oxide, calcium carbonate, polyhedral oligomeric silsesquioxanes (POSS), or recycled polymer matrices such as LDPE (low density polyethylene), EVA (ethylene vinyl acetate), HDPE (high density polyethylene), PP (polypropylene), etc. As defined herein, recycled polyolefins may be derived from regrind material that has been subjected to at least one processing method such as molding or extrusion or foaming, and thereafter the sprues, runners, flash, rejects, etc. are ground or chopped.

[0036] In one or more embodiments, the physical property modifier may be included in an amount ranging from 0.01 to 50 phr. For example, the physical property modifier may be included in an amount having a lower limit of one of 0.01, 0.1, 1.0, 5.0, 10, 15, and 20 phr and an upper limit of one of 25, 30, 35, 40, 45, and 50 phr, any lower limit being paired with any mathematically compatible upper limit.

[0037] The polymer compositions described herein may be expanded and cured to produce polymer foams, which are produced by a process combining the aforementioned polymer compositions to provide high open cell content and tunable tortuosity of the produced foams.

[0038] [Cell opener masterbatch composition] One or more embodiments of the present disclosure relate to a cell opener master batch composition. The cell opener master batch composition may include at least one cell opener and a carrier polymer. For example, the cell opener master batch stock may be formulated for storage or transportation and, if necessary, combined with a thermoplastic matrix or other materials, such as a crosslinker and a blowing agent, to produce a final polymer composition having concentrations of the above components that provide physical and chemical properties tailored to the selected end use. Thus, the master batch composition may be formulated such that the concentration of the cell opener is greater than the desired final concentration of the aforementioned polymer composition. Although the final polymer composition of the present disclosure includes a crosslinker and a blowing agent, such components may be omitted from the cell opener master batch to inhibit premature crosslinking and foaming. The cell opener master batch generally includes at least one cell opener and a carrier polymer, which may be the same or different from the thermoplastic matrix, and the cell opener master batch may include additional components, such as cell enlargers, fillers, pigments, etc.

[0039] The carrier polymer included in the cell opener masterbatch composition may be the same as the thermoplastic matrix of the final polymer composition, although other polymers may be used. In one or more embodiments, the carrier polymer may be selected from the group consisting of low density polyethylene, high density polyethylene, linear low density polyethylene, copolymers of ethylene and one or more C3-C20 alpha olefins, polypropylene, ethylene vinyl acetate copolymers, ethylene methyl acrylate copolymers, ethylene butyl acrylate copolymers, ethylene-propylene copolymers, ethylene-propylene diene copolymers, thermoplastic ethylene elastomers, metallocene polymers, polyether block amide copolymers, polyvinylidene fluoride, chlorinated derivatives thereof, and combinations thereof. Thus, as stated above, it can be understood that the carrier polymer and the thermoplastic matrix may be selected to be the same or different, and that even if the same polymer type is selected, different grades of the same polymer type may be used.

[0040] As noted above, the concentration of the cell opener in the masterbatch may be greater than the concentration of the cell opener in the final polymer composition. In one or more embodiments, the masterbatch may include about 10% to 75% by weight of the cell opener. The cell opener may be present in the masterbatch in an amount having a lower limit of 10%, 15%, 20%, 25%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, and 50% by weight and an upper limit of 25%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, 50%, 52%, 55%, 57%, 60%, 62%, 65%, 67%, 70% and 75% by weight, any lower limit may be paired with any mathematically compatible upper limit. The balance of the mass of the masterbatch composition may be the carrier polymer and additives described above.

[0041] In one or more embodiments, the cell opener masterbatch composition may be blended with a crosslinker and a blowing agent (and other optional ingredients described herein) to arrive at the polymer composition, or may be blended with a crosslinker, a blowing agent, and a crosslinkable thermoplastic matrix (and other optional ingredients described herein) to arrive at the final polymer composition. In this second scenario, it is contemplated that the cell opener masterbatch is blended with a crosslinkable thermoplastic matrix, and such blend may include a sufficient amount of the cell opener masterbatch to achieve the above-mentioned cell opener concentrations in the polymer composition. In one or more embodiments, the cell opener masterbatch may be included in the polymer composition in an amount having a lower limit of one of 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, and 25% by weight, and an upper limit of one of 10%, 12%, 15%, 17%, 20%, 25%, 30%, 35%, 40%, 45%, and 50% by weight, any lower limit may be paired with any mathematically compatible upper limit.

[0042] [Open cell foam manufacturing method] In another aspect, one or more embodiments of the present disclosure relate to a method for producing a polymer foam from the aforementioned composition, the method according to one or more embodiments comprising a two-step process of blending the polymer composition to form a foamable precursor, and then expanding and curing the foamable precursor.

[0043] The polymeric composition according to the present disclosure may be blended in any conventional mixing device or means to form a foamable precursor. In one or more embodiments, the polymeric composition may be blended by a conventional kneader, Banbury mixer, mixing roller, twin screw extruder, press, and the like. The blending step is typically carried out at a temperature below the decomposition temperature of the crosslinking agent and the foaming agent. For example, in one or more embodiments, the blending step may be carried out at a temperature ranging from about 70° C. to 150° C. As will be understood by one skilled in the art, the blending temperature depends on the melting or softening point of the crosslinkable thermoplastic matrix used in the polymeric composition and the decomposition temperature of the crosslinking agent used.

[0044] In one or more embodiments, certain components of the polymer composition may be included in a cell opener masterbatch that is prepared separately and then blended with additional components to form the foamable precursor. In such an embodiment, the carrier polymer and at least one cell opener may be included in the cell opener masterbatch. The cell opener masterbatch may optionally include other components and may be blended with the aforementioned components to form the polymer composition and the foamable precursor. The cell opener masterbatch may help improve the dispersion of the cell opener in the polymer composition and may be used in any composition. However, the cell opener masterbatch may be particularly beneficial when a surface tension modifier is used as the cell opener, especially when the cell opener is a polymer with a high softening temperature compared to the crosslinkable thermoplastic matrix.

[0045] After forming the expandable precursor in the blending step, the expandable precursor is heated in a first heating step. An exemplary embodiment of the first heating step 100 is shown in FIG. 1. FIG. 1 shows a mold 102 on two hot plates 104 of a press. The expandable precursor 106 is placed in the mold 102 for the first heating step, as shown by the press labelled 108. This first heating step is performed under positive pressure. In one or more embodiments, and as shown in FIG. 1, pressure is applied by pressing the mold with a press 110. The pressure should be sufficient to maintain the volume of the expandable precursor 106 such that it does not expand by more than 15% by volume, or more than 10% by volume, or more than 5% by volume, or more than 3% by volume, or more than 2% by volume, or more than 1% by volume in this step. When pressure is applied, the mold pressed against the expandable precursor is heated to a temperature above the decomposition temperature of the crosslinking agent and below the decomposition temperature of the chemical blowing agent. As will be appreciated by those skilled in the art, this temperature will vary depending on the type of crosslinkable thermoplastic polymer, crosslinking agent, and blowing agent used. In an exemplary embodiment, the temperature of the first heating step may range from about 130° C. to 160° C. The foamable precursor is then held at the elevated temperature for a sufficient time for the material to reach the desired crosslinking level. The time at elevated temperature will vary depending on the composition and thickness of the foamable precursor. For example, for a foamable precursor having a thickness of about 25 mm (millimeters), the time at elevated temperature under pressure may be about 40 to 60 minutes. During this step, about 2% to 40% of the blowing agent may be decomposed. As will be appreciated by those skilled in the art, the amount of time at elevated temperature during this step will depend on the thickness of the foamable precursor. A foamable precursor having a thickness of about 25 mm should be heated for about 40 to 60 minutes. However, thicker samples may require additional heating time, and thinner samples may require less heating time. Such adjustments may be made as needed, as will be appreciated by those skilled in the art.

[0046] After the first heating step, the pressure is released 112 and the foamable precursor expands to produce a primary foam 114. At this point, the foamable precursor expands to the primary foam at an expansion ratio of about 1.1 to 10.0. For example, the expansion ratio of foamable precursor to primary foam may be about 1.1, 1.2, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10.0.

[0047] The primary foam is then heated in the second heating step of the method, as shown in FIG. 2. During this step 200, the primary foam is heated using a hot plate 204 similar to that used in the first step. The primary foam 114 is heated in a volume (such as a mold) at a temperature above the decomposition temperature of the chemical blowing agent. As will be appreciated by those skilled in the art, this temperature will vary depending on the type of crosslinkable thermoplastic polymer and blowing agent used. In an exemplary embodiment, the temperature of the second heating step may range from about 160° C. to 200° C. Additional external pressure may or may not be applied during this step, including expansion in a reduced pressure environment (i.e., vacuum), but the volume to which the heated primary foam is heated is controlled to control the rate of expansion of the foam. In embodiments where pressure is applied during this step, pressure may be applied using a moving press with a piston, using a sealed mold and injecting pressurized gas, or by performing this subsequent step in a pressure vessel. During step 200, the foam expands to fill volume 206 and the foam has an expansion ratio compared to the initial volume of about 10 to 45. The expansion ratio during the second step can be about 10, 15, 20, 25, 30, 35, 40 or 45.

[0048] After the primary foam has expanded, it can be cooled to a temperature below the softening temperature of the polymer to form an open cell polymer foam 208 that fills a predetermined volume. Cooling below the softening temperature eliminates any unwanted additional expansion. After the foam has cooled, it can be removed from the expanded volume. Immediately after the cooling step, the open cell foam can have an open cell content of at least 80%. The foam can also have a flexure within a selected flexure range.

[0049] An additional mechanical deformation step may not be necessary to achieve the target degree of flexion, however, in one or more embodiments, the open cell polymer foam can be mechanically deformed to change the degree of flexion of the open cell polyolefin foam.

[0050] The above-described methods for preparing an open cell polymer foam can be used to vary the tortuosity of the foam. In such cases, the method includes selecting a target tortuosity range, selecting a polymer based on the target tortuosity range, and then proceeding with the manufacture of the polymer foam as described above.

[0051] In contrast to conventional methods for preparing open cell polymer foams, the open cell content and target tortuosity can be achieved directly from the foam synthesis process, i.e., no mechanical deformation of the foam is required to achieve high open cell content and a certain tortuosity. That is, high open cell content and a certain tortuosity can be achieved by the combination of the polymer composition and synthesis method described herein. In contrast, conventional methods generally must use mechanical deformation to achieve high open cell content. According to the present method, since high open cell content is achieved directly from the composition and synthesis process, if mechanical deformation is used, it may be to modify the tortuosity of the foam, not to increase the open cell content.

[0052] Tortuosity, as described herein, is a measure of how fluid (i.e., gas or liquid) is transported through a foam. Tortuosity is defined as the ratio between the real and apparent distances that a fluid trapped within the cell structure must cover to move from one side of the foam to the other. Figure 3 is a diagram used to illustrate how tortuosity is defined.

[0053] The formula used herein to represent the degree of tortuosity is shown in Formula (I):

number

[0054] As described herein, tortuosity is determined experimentally using electrochemical measurements as described below.

[0055] A CuSO4·5H2O solution (0.4 M) may be used as the auxiliary solution. Two copper disks (15 mm diameter) are used as electrodes. The copper electrodes can be connected to a power supply (EA-3048B Elektro-Automatik GmbH, Germany) that supplies alternating current.

[0056] First, the electrical conductivity of the solution without the foaming sample between the electrodes is measured over a certain voltage range. The electrical resistance (R c ) is determined by application of Ohm's law. Measurements are made in 0.5 volt increments over the voltage range of 3 to 6 volts. A 2 minute interval is allowed between each measurement. Conventional ammeters and voltmeters are used to measure voltage and intensity during electrical experiments.

[0057] After measuring the electrical resistance of the solution without the sample, the electrical conductivity of the solution with the foam sample placed between two copper electrodes is determined. For this purpose, a cylindrical foam specimen with a thickness of 25 mm and a diameter of 30 mm is immersed in the solution for 14 hours before the measurement to evaluate the proper and complete penetration of the auxiliary liquid inside the cell structure. After this, the sample is placed between the two copper electrodes and the electrical conductivity is measured in the same voltage range and under the same conditions and with the same equipment as used for the solution. The electrical resistance (R f ) can be obtained using Ohm's law.

[0058] The tortuosity (T) is the electrical resistance (R f ) and the electrical resistance (R c ) is defined by the formula shown in formula (III).

number

[0059] As previously discussed, the method according to one or more embodiments includes selecting a target flexion range for the open cell polymer foam. In one or more embodiments, a low target flexion range may be selected. In such embodiments, the target flexion range is 1.1 to 2.5. For example, the low target flexion range may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or 2.5. In other embodiments, a high target flexion range may be selected. In such cases, the target flexion range is 2.5 to 6.0. For example, the high target flexion range may be 2.5, 2.7, 3.0, 3.2, 3.5, 3.7, 4.0, 4.2, 4.5, 4.7, 5.0, 5.2, 5.5, 5.7, or 6.0.

[0060] After the target tortuosity is selected, a polymer composition based on the target tortuosity range may be selected. In one or more embodiments, a small amount of surface tension modifier may be used to produce a foam with high tortuosity. For example, a polystyrene polymer in an EVA matrix in an amount of 5 to 10 phr may result in a foam with a high tortuosity in the range of 2.5 to 6. On the other hand, a surface tension modifier (e.g., polystyrene) in an amount of 5 to 15 phr and a rheology modifier (e.g., amide of fatty acid) in an amount of 1 to 3 phr may produce a foam with low tortuosity, with a tortuosity in the range of 1.1 to 2.5. Additionally, a combination of a surface tension modifier in a proportion of 5 to 15 phr and an inorganic filler in a proportion of 5 to 20 phr is a method to reduce the tortuosity of the foam. After the polymer composition is selected, the polymer composition may be made into an open cell foam as described above.

[0061] As previously mentioned, in one or more embodiments, the target degree of tortuosity may be achieved directly from the method of manufacturing the open cell foam. However, in one or more embodiments, an optional mechanical deformation step may be used to change the degree of tortuosity. For example, if an open cell foam with a higher degree of tortuosity is to be produced, mechanical deformation may be used to reduce the degree of tortuosity. Mechanical deformation generally involves compressive and / or shear forces that break additional cell walls in the foam structure. In one or more particular embodiments, the foam may be mechanically deformed using rolls, for example, a set of two rolls that may be set at different rotational speeds and deformation ratios.

[0062] [Open cell polymer foam] Open cell polymer foams made from the aforementioned compositions using the aforementioned methods can provide a unique combination of physical properties useful for a wide range of applications. Open cell content is a measure of the degree of cell interconnectivity in a polymer foam. For example, a high open cell content indicates a high level of cell interconnectivity in the polymer foam. As defined herein, an open cell polymer foam is a foam having an open cell content of at least 80%.

[0063] The open cell content of the polymer foams described herein may be determined by gas pycnometer. A gas pycnometer operating under nitrogen or argon gas may be used to determine the open cell content using the formula shown in Equation (II):

number

[0064] The open cell polymeric foams described herein may have a suitable density, and in some cases may have a very low density. In one or more embodiments, the polymeric foam may have a density of 13 kg / m or less as determined in accordance with ASTM D3575-00, Suffix W-Density. 3From 60kg / m 3 In an embodiment in which the open cell polymer foam has a very low density, the open cell polymer foam may have a density in the range of 20 kg / m as determined in accordance with ASTM D3575-00, Suffix W- Density. 3 Less than 18kg / m 3 Less than or kg / m 3 It may have a density of less than 100 nm.

[0065] The open cell polymer foams disclosed herein may have particularly small cells compared to conventional open cell polymer foams. In one or more embodiments, the polymer foam may have an average cell size range of 50 to 70 microns as measured using a scanning electron microscope in accordance with ASTM D3576-98. In particular, in embodiments where smaller cell sizes are required, the polymer foam may have an average cell size range of 50 to 350 microns as measured using a scanning electron microscope in accordance with ASTM D3576-98. The average cell size may have a lower limit of one of 50, 75, 100, 125, 150, 175, and 200 microns and an upper limit of one of 175, 200, 225, 250, 375, 300, 350, 400, 500, 600, and 700 microns, and any lower limit may be paired with any mathematically compatible upper limit.

[0066] The open-cell polymer foams disclosed herein exhibit unique mechanical properties. For example, when subjected to compressive strain, the response is strain rate dependent. When a polymer foam with high flexurality is subjected to compressive strain at low strain rates, it behaves as a flexible open-cell product, such as a flexible polyurethane foam. However, when this same foam product is subjected to a compression test (e.g., impact test) performed at high strain rates, it behaves very similarly to a closed-cell foam, and as a result, it does not resemble a flexible polyurethane foam at all. Without wishing to be bound by any particular mechanism of theory, it is believed that the reason for this strain rate dependent behavior is the high flexibility of the cell structure. At low strain rates, the gas trapped within the cell structure has enough time to leave the material when the material is deformed (i.e., the time for the gas to escape is less than the time scale of the experiment), and as a result (and unlike closed-cell foams), the gas phase does not contribute to the stress value achieved. However, at high strain rates, the gas trapped in the cells containing the cellular structure does not have time to escape the structure because the time for the gas to leave the structure is greater than the time scale of the experiment. As a result, the gas phase has a positive contribution to the material stress when the product is impact tested. This dual property of foams when subjected to compressive strain makes them an ideal candidate for applications requiring both impact protection and comfort.

[0067] Open cell foams made by conventional methods that require mechanical deformation to open the cells suffer from reduced thermal stability to mechanically open the cells. Thus, the polymer foams disclosed herein provide improved thermal stability compared to conventional open cell foams. In one or more embodiments, the polymer foams may have an average thermal dimensional stability of ±1% in each direction (length, width, and thickness) when measured at 70° C. according to ASTM D3575, Suffix S Thermal Stability. In one or more embodiments, the polymer foams may have an average thermal dimensional stability of ±5% in each direction (length, width, and thickness) when measured at 85° C., 90° C., or 100° C. according to ASTM D3575, Suffix S Thermal Stability. In one or more exemplary embodiments, the polymer foam may have a thermal stability of ±5% when measured at 85° C. for a foam based on EVA with 19% vinyl acetate, or at 100° C. for a foam based on LDPE, or at 90° C. for a foam based on EBA with 17% butyl acrylate.

[0068] Sound absorption is an important application of flexible polyurethane foams. These materials usually exhibit maximum absorption at frequencies higher than 2000-2500 Hz. However, some specific applications require materials with good absorption capacity below 2000 Hz. The polymer foams disclosed herein provide higher sound absorption capacity below 2000 Hz compared to conventional foams such as flexible polyurethane foams. The polymer foams have an average sound absorption capacity of at least 0.50 between f1=500 Hz and f2=2000 Hz, as measured according to ASTM 1050-98 and calculated using the formula shown in formula (IV).

number

number

[0069] The polymer foams described herein exhibit high oil absorption capacity. Foams with low tortuosity have many useful characteristics for oil spill remediation. Extremely low density allows the foam to absorb many volumes of oil per volume of foam. In addition, flexible polyolefins such as LDPE or EVA can be used in one or more embodiments as crosslinkable thermoplastics to provide flexible foams for oil absorption, allowing for foam reuse. After absorbing oil, the flexible foams can be squeezed and reused for many cycles. The high open cell content and low density of the foams disclosed herein also contribute to efficient oil absorption. Polyolefin-based materials such as many crosslinkable thermally crosslinkable matrices disclosed herein are hydrophobic and oleophilic, providing oil-water selectivity.

[0070] The oil absorption capacity as disclosed herein may be determined by placing a sample on the surface of the oil. The foam is placed on the oil sample without immersion or squeezing and allowed to sit for 10 minutes. The oil absorption is calculated using the formula shown in Equation (IV):

number

[0071] In an exemplary embodiment, the oil absorption capacity is 22 kg / m 3 The open cell EVA foam (12% vinyl acetate content) with a density of 2.0 and a flexural index of 2.6 was compared with Foam W. Foam Up to 25 grams of oil per gram of Oil In another exemplary embodiment, the thickness may be 17 kg / m 3 The open cell EVA foam (18% vinyl acetate content) has a density of 1.0 and a flexural index of 1.9. Foam 43 grams of oil per gram of Oil It can be made to the same height.

[0072] The open cell foam according to one or more embodiments may have a high ability to dampen vibration. This property can be measured by tan δ, the ratio of storage modulus (E') to loss modulus (E'') in a Dynamic Mechanical Analysis (DMA) experiment performed in compression mode according to ASTM D5024-01. The open cell foam may have a tan δ at 23°C and a frequency of 1 Hz that is 0.5 or greater, or 0.7 or greater, or 0.9 or greater. In one or more specific embodiments, the open cell foam has a tensile strength of 17 kg / m 3 For an open cell EVA foam (vinyl acetate content 18%) having a density of 20 kg / m and a flexural index of 1.9, the foam may have a tan δ of 0.5 or more at 23° C. and a frequency of 1 Hz. 3 For an open cell EBA foam (butyl acrylate content 17%) with a density of 0.2 and a flexural index of 1.9, it may be equal to 0.9 at 23° C. and a frequency of 1 Hz.

[0073] The open cell foams described herein can be easily thermoformed into complex shapes using conventional methods involving pressure (or vacuum) and temperature. Additionally, the foams can be laminated with other materials (fabrics, foams, solid polymers, etc.) using traditional means such as adhesive bonding or thermal bonding. Additionally, the materials can be washed using conventional washing machines with standard temperature programs and laundry detergents. Such physical properties make them useful for applications in the clothing industry to produce components such as bras, body protection components for sports fields, thermal clothing, cups, etc.

[0074] [Goods] The open cell polymer foam according to one or more embodiments of the present disclosure may be used to manufacture many polymer articles for a variety of end uses, including cushioning (seats, mattresses, cushions, mats, etc.), protective components for sports fields, packaging for various types of goods, sealing applications and gaskets, liquid absorbing articles (water or oil based), filters, sound absorbing materials, clothing, bras, carpet underlay, furniture products, vibration damping materials, components for automobiles (crash pads, carpet backing, energy management, filters, headliners, headrests, armrests, seats, sound insulation (roof), steering wheels, sun visors, trim, vibration damping), bicycle and motorcycle seats, helmets, crafts, diapers, earplugs, electronic products, toys, sanitary napkins, sealers for construction fields, insulation materials, cushioning materials for precision instruments or transportation or glass, carriers for septic tanks, sealing and / or sound absorbing materials for systems including air conditioning systems, refrigeration systems, speakers, and personal computers, and sealants for LCD TVs. EXAMPLES

[0075] [Sample formulation] Examples I-VI are open cell foams prepared from various formulations according to the teachings of the present disclosure. The formulations of the samples of Examples I-VI are shown in Table 1. Examples I-III are open cell foams based on formulations including EVA (ethylene vinyl acetate copolymer) with 18% by weight vinyl acetate as a crosslinkable thermoplastic matrix; Example IV is an ultra-low density open cell foam based on EBA (ethylene butyl acrylate copolymer) with 17% butyl acrylate as a crosslinkable thermoplastic matrix; Example V is a high flexibility open cell foam based on LDPE (low density polyethylene) as a crosslinkable thermoplastic matrix; and Example VI is an ultra-low density foam based on EVA with 18% vinyl acetate as a crosslinkable thermoplastic matrix. [Table 1]

[0076] [Open cell foam preparation method] The open cell foam examples shown herein were prepared using the following procedure.

[0077] 1. Mixing the ingredients For Examples I and III, the foamable precursor was prepared using a conventional two roll mill with two rolls heated to 118° C., with a mixing time of 15 minutes. The equipment used is DW5110 from Hefei Fanyuan Instrument Co., ltd.

[0078] For those formulations containing polystyrene (PS) (Examples II, IV, V and VI), cell opener masterbatches were prepared containing the base polymer of each formulation as the carrier polymer and PS as the cell opener in a mass ratio of 70:30 (carrier:cell opener). The masterbatches were produced in a twin screw extruder ZK 25 T Teachline from Dr. Collin at temperatures ranging from 100°C (in the hopper) to 180°C (in the die).

[0079] This masterbatch was then incorporated into the formulation using a conventional two-roll mill with two rolls heated to 118°C, with a mixing time of 15 minutes, with the material ratio of foamable precursors shown in Table 1. The equipment used is DW5110 from Hefei Fanyuan Instrument Co.,ltd.

[0080] 2. The first heating step to produce the primary foam The process was carried out with a conventional two-plate hotplate press manufactured by Talleres Remtex (Barcelona, ​​Spain). The mould was made from aluminium. The inner dimensions of the mould were 79x79x25 mm. 3 The conditions used for each experiment are detailed in Table 2. The mold was completely filled with the foamable precursor produced in the mixing process.

[0081] 3. The second heating step to produce an open cell foam The process was carried out with a conventional two-plate hotplate press manufactured by Talleres Remtex (Barcelona, ​​Spain). The mould in which the primary foam was introduced was made from aluminium. The internal dimensions of this mould were 200x200x100 mm. 3 The conditions used for each experiment are detailed in Table 2.

[0082] 4. Cooling to below the softening point This cooling step was carried out by introducing the mould used in the second heating step into water for 40 minutes.

[0083] The process conditions used in the preparation of Examples I-VI are summarized in Table 2. [Table 2]

[0084] Open Cell Foam Properties The open cell foams produced according to the formulation and manufacturing process described above were evaluated for density, open cell content and flexurality. The physical properties of the foams of Examples I to VI are shown in Table 3. [Table 3]

[0085] Although a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications to the exemplary embodiments are possible without essentially departing from the invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover not only the structures described herein as performing the stated function and structural equivalents, but also equivalent structures. Thus, while nails and screws may not be structural equivalents in that nails employ cylindrical surfaces to fasten wooden pieces together, whereas screws employ helical surfaces, in the context of fastening wooden pieces, nails and screws may be equivalent structures. It is Applicant's intention not to invoke 35 USC § 112(f) to limit the scope of the claims herein, except where the claims expressly use the words "means for" with the relevant function. [Explanation of symbols]

[0086] 100...First heating step 102 Mold 104: Hot plate 106...Foamable precursor 108 Press machine 110 Press machine 112 Press machine 114 Primary foam 200 Second heating process 204 Hot plate 206...Volume 208 Open cell polymer foam 300···Products 304 Cell wall 306...hole

Claims

1. a crosslinkable thermoplastic matrix; cross-linking agent; a blowing agent; and At least one cell opener 1. A polymer composition comprising:

2. 2. The polymer composition of claim 1, wherein the crosslinkable thermoplastic matrix is ​​selected from the group consisting of low density polyethylene, high density polyethylene, linear low density polyethylene, copolymers of ethylene and one or more C3 to C20 alpha olefins, polypropylene, ethylene vinyl acetate copolymer, ethylene methyl acrylate copolymer, ethylene butyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene diene copolymer, thermoplastic ethylene elastomer, metallocene polymer, polyether block amide copolymer, polyvinylidene fluoride, copolyester, polyolefin elastomer, vulcanized thermoplastic elastomer or styrene block copolymer, chlorinated derivatives thereof, and combinations thereof.

3. The crosslinking agent is present in an amount ranging from 0.1 to 2.0 phr and is selected from the group consisting of 1,1-bis(tert-butylperoxyl)-3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, 2,2-bis(tert-butylperoxyl)butane, dicumyl peroxide, diether amyl peroxide, diether butyl peroxide, 1,2-bis(tert-butyl)-isopropylbenzene, 2,5-bis(tert-butylperoxy)-2-5-dimethylhexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl) ...bis(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-bis(tert-butylperoxy)-2-5-dimethylhexane, 2,5-bis(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-bis(tert-butylperoxy)-2-5-dimethylhexane, 2,5-bis(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-bis(tert- Propyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-tuylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl perbenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, t-butylcumyl peroxide, benzoyl peroxide; dicumyl peroxide; di-tert-butyl peroxide; 00-Tert-amyl-0-2-ethylhexyl monoperoxycarbonate; tert-butylcumyl peroxide; tert-Butyl 3,5,5-trimethylhexanoate peroxide; tert-butyl peroxybenzoate; 2-ethylhexyl carbonate tert-butyl peroxide; 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane; 1,1-di(tert-butylperoxide)-3,3,5-trimethylcyclohexane; 2,5-dimethyl-2,5-di(tert-butylperoxide)hexyne-3; 3,3,5,7,7-pentamethyl-1,2,4-trioxepane; butyl 4,4-di(tert-butylperoxide)valerate; di(2,4-dichlorobenzoyl)peroxide; di(4-methylbenzoyl)peroxide; peroxide di(tert-butylperoxyisopropyl)benzene, benzoyl peroxide, 2,5-di(cumylperoxy)-2,5-dimethylhexane, 2,5-di(cumylperoxy)-2,5-dimethylhexyne-3,4-methyl-4-(t-butylperoxy)-2-penta peroxyl, butyl peroxy-2-ethyl hexanoate, tert-butyl peroxypivalate, tertiary butyl peroxyneodecanoate, t-butyl peroxybenzoate, t-butyl peroxy-2-ethyl hexanoate, 4-methyl-4-(t-amylperoxy)-2-pentanol, 4-methyl-4-(cumylperoxy)-2-pentanol, 4-methyl-4-(t-butylperoxy)-2-pentanone, 4-methyl-4-(t-amylperoxy)-2-pentanone, 4-methyl 2,5-dimethyl-4-(cumylperoxy)-2-pentanone, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-amylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(t-amylperoxy)hexyne-3, 2,5-dimethyl-2-t-butylperoxy-5-hydroperoxyhexane, 2,5-dimethyl-2-cumylperoxy-5-hydroperoxyhexane, 2,5-dimethyl-2- t-Amylperoxy-5-hydroperoxyhexane, m / p-alpha,alpha-di[(t-butylperoxy)isopropyl]benzene, 1,3,5-tris(t-butylperoxyisopropyl)benzene, 1,3,5-tris(t-amylperoxyisopropyl)benzene, 1,3,5-tris(cumylperoxyisopropyl)benzene, di[1,3-dimethyl-3-(t-butylperoxy)butyl]carbonate, di[1,3-dimethyl-3-(t-amylperoxy)butyl]carbonate, di[1,3-dimethyl-3-(cumylperoxy)butyl]carbonate, di-t-amyl peroxide, t-amyl cumyl peroxide, t-butyl-isopropenyl cumyl peroxide, 2,4,6-tri(butylperoxy)-s-triazine, 1,3,5-tri[1-(t-butylperoxy)-1-methylethyl]benzene, 1,3,5-tri-[(t-butylperoxy)isopropyl]benzene, 1,3-dimethyl-3-(t-butylperoxy)butanol, 1,3-dimethyl-3-(t-amylperoxy)butyl peroxydicarbonate, di(2-phenoxyethyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, dimyristyl peroxydicarbonate, dibenzyl peroxydicarbonate, di(isobomyl)peroxydicarbonate, 3-cumylperoxy-1,3-dimethylbutyl methacrylate, 3-t-butylperoxy-1,3-dimethylbutyl methacrylate, 3-t-amylperoxy-1,3-dimethylbutyl methacrylate, tri(1,3-dimethyl-3- t-Butylperoxybutyloxy)vinylsilane, 1,3-dimethyl-3-(t-butylperoxy)butyl N-[1-{3-(1-methylethenyl)-phenyl}1-methylethyl]carbamate, 1,3-dimethyl-3-(t-amylperoxy)butyl N-[1-{3(1-methylethenyl)-phenyl}-1-methylethyl]carbamate, 1,3-dimethyl-3-(t-cumylperoxy))butyl N-[1-{3-(1-methylethenyl)-phenyl}-1-methylethyl]carbamate, 1,1- Di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-butylperoxy)cyclohexane, n-butyl 4,4-di(t-amylperoxy)valerate, ethyl 3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, 3,6,6,9,9-pentamethyl-3-ethoxycarbonylmethyl-1,2,4,5-tetraoxacyclononane, n-butyl-4,4-bis(t-butylperoxy)valerate, ethyl-3,3-Di(t-amylperoxy)butyrate, benzoyl peroxide, OO-t-butyl-O-hydrogen-monoperoxy-succinate, OO-t-amyl-O-hydrogen-monoperoxy-succinate, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane (or methyl ethyl ketone peroxide cyclic trimer), methyl ethyl ketone peroxide cyclic dimer, 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane, 2,5-di Methyl-2,5-di(benzoylperoxy)hexane, t-butyl perbenzoate, t-butyl peroxyacetate, t-butylperoxy-2-ethylhexanoate, t-amyl perbenzoate, t-amyl peroxyacetate, t-butylperoxyisobutyrate, 3-hydroxy-1,1-dimethyl t-butylperoxy-2-ethylhexanoate, OO-t-amyl-O-hydrogen-monoperoxysuccinate, OO-t-butyl-O-hydrogen-monoperoxysuccinate, di-t-butyldi Peroxyphthalate, t-butylperoxy(3,3,5-trimethylhexanoate), 1,4-bis(t-butylperoxycarbo)cyclohexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl-peroxy-(cis-3-carboxy)propionate, allyl 3-methyl-3-t-butylperoxybutyrate, OO-t-butyl-O-isopropyl monoperoxycarbonate, OO-t-butyl-O-(2-ethylhexyl) monoperoxycarbonate, 1,1,1-tris[2-( t-butylperoxy-carbonyloxy)ethoxymethyl]propane, 1,1,1-tris[2-(t-amylperoxy-carbonyloxy)ethoxymethyl]propane, 1,1,1-tris[2-(cumylperoxy-carbonyloxy)ethoxymethyl]propane, OO-t-amyl-O-isopropyl monoperoxycarbonate, di(4-methylbenzoyl)peroxide, di(3-methylbenzoyl)peroxide, di(2-methylbenzoyl)peroxide, didecanoyl peroxide, dilauroyl peroxide, 2,The polymer composition according to claim 1 or 2, wherein the peroxide is selected from the group consisting of 4-dibromo-benzoyl peroxide, succinic acid peroxide, dibenzoyl peroxide, di(2,4-dichloro-benzoyl) peroxide, and combinations thereof.

4. The blowing agent is present in an amount ranging from 1 to 60 phr and is selected from the group consisting of azodicarbonamide, azobisisobutyronitrile, oxydibenzenesulfonylhydrazide, 5-phenyltetrazole, sodium bicarbonate, citric acid, urea, N,N'-dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosoterephthalamidotrinitrodimethyl(timethyl)triamine, 4,4'-oxybis(benzenesulfonylhydrazide), p-toluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, allylbis(sulfonylhydrazide), p-toluylenesulfonylsemicarbazide, 4,4'-oxybis(benzenesulfonylhydrazide), p-toluene ...

4. The polymer composition according to claim 1, wherein the blowing agent is either a chemical blowing agent selected from the group consisting of benzenesulfonylsemicarbazide, trichloromonofluoromethane, dichloromonofluoromethane, 5-morpholyl-1,2,3,4-thiatriazole, and combinations thereof, or a physical blowing agent selected from the group consisting of propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, isohexane, cyclohexane, ethanol, methanol, nitrogen gas, carbon dioxide gas, carbon monoxide gas, hydrofluoroolefins (HFOs), hydrofluorocarbons (HFCs), and combinations thereof.

5. 5. The polymer composition of claim 1, wherein the at least one cell opener is selected from the group consisting of a surface tension modifier, a rheology modifier, an inorganic compound, and combinations thereof.

6. When at least one of the cell openers comprises the surface tension modifier, the surface tension modifier is present in an amount ranging from 1 to 50 phr; and / or 6. The polymer composition of claim 5, wherein the surface tension modifier is selected from the group consisting of polyamide, polystyrene, styrene acrylonitrile, polypropylene, a polyolefin having a weight average molecular weight higher than that of the crosslinkable thermoplastic matrix, polymethyl methacrylate, polyethylene terephthalate, glycol-modified polyethylene terephthalate, polyhydroxyalkanoate, polylactic acid, starch, polyvinyl alcohol, natural rubber, ethylene-propylene-diene monomer, polydimethylsiloxane, acrylonitrile butadiene rubber, polyether block amide, thermoplastic polyolefin elastomer, styrene block copolymer, thermoplastic polyurethane elastomer, thermoplastic vulcanizate, thermoplastic copolyester elastomer, and combinations thereof.

7. When at least one of the cell openers comprises the rheology modifier, the rheology modifier is present in an amount ranging from 0.05 to 7.0 phr; and / or 7. The polymer composition of claim 5 or 6, wherein the rheology modifier is a primary or secondary amide or bisamide fatty acid and combinations thereof.

8. When the at least one cell opener comprises the inorganic compound, the inorganic compound is present in an amount ranging from 1 to 50 phr; and / or 8. The polymer composition of claim 5, wherein the inorganic compound is selected from the group consisting of talc, calcium carbonate, sodium carbonate, silicate, mica, silica, aluminum hydroxide, magnesium hydroxide, montmorollonite, sepiolite, and combinations thereof.

9. 9. The polymer composition of claim 1, further comprising a foaming accelerator in an amount ranging from 0.01 to 4.0 phr, The polymer composition, wherein the foaming accelerator is selected from the group consisting of transition metal compounds, zinc oxide, polyols, ureas, alkanolamines, organic acids, and combinations thereof.

10. 10. The polymer composition of claim 1, further comprising a processing aid, a cell enlarger, and a physical property modifier selected from the group consisting of fillers, additives, and combinations thereof in an amount ranging from 0.05 to 2.0 phr.

11. 11. An open cell polymer foam prepared from the composition of any one of claims 1 to 10.

12. 1. An open cell polymer foam, including a thermoplastic polymer foam, comprising: The thermoplastic polymer foam is an open cell content of at least 80%; and 13 to 60 kg / m ３ Density in the range an open cell polymer foam comprising:

13. an open cell content of at least 90%; and / or a density of less than 20 kg / m 3 ; and / or 13. The open cell polymer foam of claim 11 or 12, having an average cell size in the range of 50 to 700 microns as measured using a scanning electron microscope according to ASTM D3576-98.

14. An open-cell polymer foam described in any one of claims 11 to 13, having a tortuosity of either 1.1 to 2.5 or 2.5 to 6.0, as determined using an electrochemical measurement method.

15. The following physical properties: - Thermal dimensional stability of an average of ±1% in each direction (length, width, and thickness) when measured at 70°C according to ASTM D3575, Suffix S Thermal Stability; an average sound absorption capacity of at least 0.50 between f 1 =500 Hz and f 2 =2000 Hz, measured according to ASTM 1050-98 and calculated using the formula shown in formula (IV); [Equation 1] [Equation 2] an oil absorption capacity of at least 25 grams of oil W oil per gram mass of foam W Foam; 15. The open-cell polymer foam of claim 11, wherein the open-cell polymer foam has at least one of the following properties:

16. 16. An article comprising the open cell polymer foam of any one of claims 11 to 15, An article selected from the group consisting of seats, mattresses, cushions, mats, sports protection materials, packaging, gaskets, liquid absorbent articles, filters, sound absorbing materials, clothing, bras, carpet underlays, furniture products, vibration damping materials, automotive crash pads, automotive carpet backings, automotive energy management, automotive filters, automotive headliners, automotive headrests, automotive armrests, automotive seats, automotive roof sound insulation, automotive steering wheels, automotive sun visors, automotive trim, bicycle seats, motorcycle seats, helmets, crafts, diapers, earplugs, electronic products, toys, sanitary napkins, sealers for the construction industry, heat insulation materials, cushioning materials for precision instruments or transportation or glass, carriers for septic tanks, sealants for air conditioning systems, sealants for refrigeration systems, sealants for speakers, sealants for computers, sound absorbing materials for air conditioning systems, sound absorbing materials for refrigeration systems, sound absorbing materials for speakers, sound absorbing materials for computers, and sealants for LCD TVs.

17. 1. A method for adjusting the flexibility of an open cell polymer foam, comprising: selecting a target flexion range; selecting a polymer composition based on the target tortuosity range; blending the polymer composition to form a foamable precursor, the polymer composition comprising: crosslinkable thermoplastic polymers; cross-linking agent; Chemical blowing agents; and at least one cell opener; a process comprising: heating the foamable precursor under positive pressure to a temperature above the decomposition temperature of the crosslinker and below the decomposition temperature of the chemical blowing agent to produce a primary foam; heating the primary foam to a temperature above the decomposition temperature of the chemical blowing agent; and cooling the primary foam to a temperature below the softening temperature of the crosslinkable thermoplastic polymer to form an open-cell polymer foam having a target flexural range, Optionally, the target tortuosity range is determined using electrochemical measurements and is either 1.5 to 2.5 or 2.5 to 6.

0.

18. 1. A method for producing an open cell polymer foam, comprising: heating a foamable precursor, the foamable precursor comprising: crosslinkable thermoplastic polymers; cross-linking agent; Chemical blowing agents; and at least one cell opener; heating the foamable precursor under positive pressure to a temperature above the decomposition temperature of the crosslinker and below the decomposition temperature of the chemical blowing agent to produce a primary foam; heating the primary foam to a temperature above the decomposition temperature of the chemical blowing agent; and cooling the primary foam to a temperature below the softening temperature of the crosslinkable thermoplastic polymer to form an open-cell polymer foam having a desired flexural range; Including, Optionally, - blending the crosslinkable thermoplastic polymer, the crosslinking agent, the chemical blowing agent, and one or more cell openers to form the expandable precursor prior to the heating step; and / or - mechanically deforming the open cell polymer foam to change the degree of tortuosity of the open cell polymer foam; and / or - preparing a cell opener masterbatch comprising a carrier polymer and at least one cell opener prior to said blending step, wherein said blending step blends said crosslinking agent and said chemical blowing agent, and optionally said crosslinkable thermoplastic; further comprising The method wherein the open cell polymer foam has an open cell content of at least 80% immediately after the step of cooling the primary foam.

19. 19. The method of claim 18, wherein the foamable precursor comprises the polymer composition of any one of claims 1 to 10.

20. While heating the foamable precursor under positive pressure, the foamable precursor expands with an expansion ratio of 1.5 to 10.0; and / or 20. The method of claim 18 or 19, wherein during heating the primary foam, the primary foam expands with an expansion ratio of 15 to 40 relative to the initial volume of the foamable precursor.

21. 21. An open cell polymer foam made from the method of any one of claims 18 to 20.

22. a carrier polymer; and 10% to about 70% by weight of at least one cell opener 1. A cell opener masterbatch composition comprising:

23. 23. The masterbatch composition of claim 22, wherein the at least one cell opener is selected from the group consisting of a surface tension modifier, a rheology modifier, an inorganic compound, and combinations thereof; the surface tension modifier is selected from the group consisting of polystyrene, styrene acrylonitrile, polypropylene, polyolefins having a weight average molecular weight higher than the crosslinkable thermoplastic matrix, polymethyl methacrylate, polyethylene terephthalate, glycol-modified polyethylene terephthalate, polyhydroxyalkanoates, polylactic acid, starch, polyvinyl alcohol, natural rubber, ethylene-propylene-diene monomer, polydimethylsiloxane, acrylonitrile butadiene rubber, polyether block amides, thermoplastic polyolefin elastomers, styrene block copolymers, thermoplastic polyurethane elastomers, thermoplastic vulcanizates, thermoplastic copolyester elastomers, and combinations thereof, preferably polystyrene; - said rheology modifier is selected from the group consisting of erucamide, oleamide, docosanamide, stearamide, ethylene bis-oleamide, stearyl erucamide, oleyl palmitamide, and combinations thereof; - said inorganic compounds are selected from the group consisting of talc, calcium carbonate, sodium carbonate, silicates, mica, silica, aluminum hydroxide, magnesium hydroxide, montmorillonite, sepiolite, and combinations thereof; and 23. The masterbatch composition of claim 22, wherein the carrier polymer is selected from the group consisting of low density polyethylene, linear low density polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene methyl acrylate copolymer, ethylene butyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene diene copolymer, thermoplastic elastomers including polyether block amide copolymers, copolyesters, polyolefin elastomers, vulcanized thermoplastic elastomers or styrenic block copolymers, metallocene polymers, polyvinylidene fluoride, chlorinated derivatives thereof, and combinations thereof.

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