Thermoplastic resin composition, compatibilizer, multilayer structure, method for manufacturing thermoplastic resin composition, package, and food package

Abstract

The present invention provides the following as a thermoplastic resin composition capable of improving compatibility between different types of resins in a mixed resin, preventing generation of phase-separated foreign matter (gum), preventing generation of gel and deterioration of color tone, and improving transparency of an obtained molded article, and simultaneously having excellent impact resistance.　A thermoplastic resin composition containing an amine-modified resin (A) and a copolymer (B) having a structural unit derived from maleic anhydride, wherein the mass ratio of the amine-modified resin (A) to the copolymer (B) having a structural unit derived from maleic anhydride is 65 / 35 to 99 / 1 in terms of A / B.

Description

Thermoplastic resin composition, compatibilizer, multilayer structure, method for producing thermoplastic resin composition, packaging, and food packaging

[0001] The present disclosure relates to a thermoplastic resin composition, a compatibilizer, a multilayer structure, a method for producing a thermoplastic resin composition, a package, and a food package.

[0002] A recycling technology aimed at reducing the amount of plastic packaging waste is known in which multilayer structures containing multiple types of resins are collected, pulverized by grinding or other methods, melt-kneaded, granulated, molded, and reused as a regrind layer for a multilayer structure. However, when the mixed resin obtained in this manner contains an ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH resin") and a polyolefin resin, there is a problem in that the EVOH resin and the polyolefin resin are poorly compatible. As a result, the EVOH resin aggregates within the recycled resin layer, affecting the quality of the recycled multilayer structure, resulting in poor recyclability.

[0003] As one means for solving the above problem, Patent Document 1 describes the use of a mixed resin in order to improve recyclability, which contains, per 100 parts by mass of polyolefin (A), 0.1 to 20 parts by mass of ethylene-vinyl alcohol copolymer (B) having an ethylene unit content of 15 to 60 mol% and a degree of saponification of 85 mol% or more, and 0.1 to 10 parts by mass of block copolymer (C) of aromatic vinyl compound and olefin, wherein block copolymer (C) of aromatic vinyl compound and olefin has at least one selected from the group consisting of halogen, epoxy group, carboxy group, and group having a carboxylic acid anhydride structure.

[0004] Japanese Patent Application Laid-Open No. 2021-88684

[0005] The mixed resin described in Patent Document 1 can reduce deterioration in color tone and adhesion of resin degradation products to the screw and die even when melt molding is repeated, and can produce molded products with excellent appearance. However, according to the investigations of the present inventors, it has been found that there is room for further improvement in the transparency and impact resistance of the molded products.

[0006] The present disclosure has been made in consideration of such problems, and provides a thermoplastic resin composition that improves the compatibility between different resins in a mixed resin, prevents the generation of phase-separated foreign matter (die deposits), prevents the generation of gel and deterioration in color tone, and further improves the transparency of the resulting molded article, while also having excellent impact resistance.

[0007] As a result of extensive research to solve the above problems, the present inventors have found that by preparing a thermoplastic resin composition containing an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride in a specific ratio, the compatibility between the different resins in the mixed resin is improved, the generation of phase-separated foreign matter (dye deposits) is prevented, the generation of gel and deterioration in color tone are prevented, and further, the transparency of the obtained molded article can be improved, and the impact resistance of the molded article can be improved.

[0008] That is, the present disclosure provides the following [1] to

[11] . [1] A thermoplastic resin composition comprising an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride, wherein the mass ratio of the amine-modified resin (A) to the copolymer (B) having structural units derived from maleic anhydride, expressed as A / B, is 65 / 35 to 99 / 1. [2] The thermoplastic resin composition according to [1], wherein the amine-modified resin (A) is an amine-modified elastomer. [3] The thermoplastic resin composition according to [1], wherein the amine-modified resin (A) is an amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene. [4] The thermoplastic resin composition according to [1], wherein the copolymer (B) having structural units derived from maleic anhydride is a multi-component olefin copolymer (B1) having structural units derived from maleic anhydride, comprising structural units (X1) derived from a monomer selected from ethylene and an α-olefin having 3 to 10 carbon atoms and structural units (Z1) derived from maleic anhydride. [5] The thermoplastic resin composition according to [4], wherein the multi-olefin copolymer (B1) having structural units derived from maleic anhydride is at least one selected from the group consisting of ethylene-maleic anhydride-methyl acrylate copolymer, ethylene-maleic anhydride-ethyl acrylate copolymer, ethylene-maleic anhydride-methyl methacrylate copolymer, ethylene-maleic anhydride-ethyl methacrylate copolymer, and ethylene-maleic anhydride-vinyl acetate copolymer. [6] A compatibilizer comprising the thermoplastic resin composition according to any one of [1] to [5]. [7] A multilayer structure having a layer comprising the thermoplastic resin composition according to any one of [1] to [5]. [8] The multilayer structure according to [7], wherein the layer comprising the thermoplastic resin composition further comprises a polyolefin resin. [9] A method for producing the thermoplastic resin composition according to any one of [1] to [5], comprising mixing the amine-modified resin (A) and the copolymer (B) having structural units derived from maleic anhydride.

[10] A package comprising the multilayer structure according to [7] or [8].

[11] A food package comprising the multilayer structure according to [7] or [8].

[0009] The thermoplastic resin composition of the present disclosure improves the compatibility between different resins in a mixed resin, prevents the generation of phase-separated foreign matter (seam buildup), prevents the generation of gel and deterioration in color tone, and further improves the transparency of the resulting molded article, thereby improving the impact resistance of the molded article.

[0010] Embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following description and can be modified as desired without departing from the spirit and scope of the present disclosure. In this specification, when a term is expressed using "to" followed by a numerical value or physical property value, the term is used to include the values ​​before and after the term. Furthermore, the expressions "X or greater" (X is any number) or "Y or less" (Y is any number) also encompass the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, "X and / or Y (X and Y are any configurations)" refers to at least one of X and Y, and can mean three possibilities: X only, Y only, or X and Y. Regarding numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range can also be replaced with the values ​​shown in the examples.

[0011] Hereinafter, the monomer units contained in the copolymer resin may be simply referred to as "units." For example, a monomer unit based on ethylene may be referred to as an "ethylene unit."

[0012] In the present disclosure, the melt flow rate (MFR) and density of a resin are values ​​measured as follows.

[0013] <MFR> According to JIS K7210, it is measured under a load of 2.16 kg at a temperature of 230°C (for amine-modified resin (A)), 190°C (for copolymer (B) having structural units derived from maleic anhydride), 190°C (for ethylene-based resins among polyolefin resins), or 210°C (for propylene-based resins and EVOH resins among polyolefin resins). When these are mixtures, the MFR is the weighted average of the individual MFRs based on the mixture mass ratio.

[0014] <Density> Measured by the underwater displacement method in accordance with JIS K7112.

[0015] Resin Composition The thermoplastic resin composition of the present disclosure (hereinafter also referred to as "the thermoplastic resin composition") contains an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride (hereinafter also simply referred to as "copolymer (B)") in a specific ratio. The thermoplastic resin composition can improve the compatibility between different resins, particularly the compatibility between EVOH resin and polyolefin resin, and therefore can be suitably used as a compatibilizer, and can be most suitably used as a compatibilizer for EVOH resin.

[0016] <Amine-Modified Resin (A)> The present thermoplastic resin composition contains an amine-modified resin (A). Since the present thermoplastic resin composition contains the amine-modified resin (A), it does not undergo a chemical reaction with the EVOH resin during the recycling process, and the generation of crosslinked gel can be suppressed, making it suitable for use as a compatibilizer. Among these, an amine-modified elastomer is preferred as the amine-modified resin (A) from the viewpoint of recyclability.

[0017] [Amine-Modified Elastomer] The amine-modified elastomer has an amino group at least partially contained in an elastomer (thermoplastic elastomer) and is obtained by introducing an amino group into the elastomer. Here, the amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group, and among these, a primary amino group or a secondary amino group is particularly preferred. Furthermore, when introducing the amino group into the elastomer, an organic amine is usually used.

[0018] Specific examples of the organic amine include alkylamines, alkenylamines, arylamines, aralkylamines, and cyclic nitrogen-containing compounds.

[0019] Examples of the alkylamines include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, s-butylamine, isobutylamine, t-butylamine, and pentylamine. Examples of the alkenylamines include dodecenylamine, octadecenylamine, and docosenylamine. Examples of the arylamines include aniline, methylaniline, ethylaniline, p-isopropylaniline, and N-methylaniline. Examples of the aralkylamines include benzylamine, 1-phenylethylamine, and 2-phenylethylamine. Examples of the cyclic nitrogen-containing compounds include cyclic alkylamines such as cyclohexylamine and dicyclohexylamine; cyclic imides such as imidazolidinone; and heterocyclic amines such as thienylamine and quinolylamine. These organic amines can be used alone or in combination of two or more.

[0020] From the viewpoint of compatibility, the modification amount with the organic amine is preferably 0.1 to 20 mol %. Here, the modification amount with the organic amine represents the ratio (mol %) of the partial structure derived from the organic amine to the total number of moles of the structural units constituting the amine-modified elastomer. It is preferably 0.001 to 10, more preferably 0.01 to 5.0.

[0021] The amine-modified elastomer is preferably an amine-modified block copolymer of an aromatic vinyl compound and an olefin and / or a hydrogenated product thereof, and from the viewpoint of improving compatibility between different resins, an amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene and / or a hydrogenated product thereof is particularly preferred.

[0022] Examples of the aromatic vinyl compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethylstyrene, vinyltoluene, and p-tert-butylstyrene. These compounds can be used alone or in combination of two or more. Among these, styrene is preferred.

[0023] Examples of the olefin include ethylene, butylene, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and farnesene. These can be used alone or in combination of two or more. Of these, conjugated dienes such as 1,3-butadiene and isoprene are preferred.

[0024] The amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene preferably has a block containing structural units derived from styrene and a block containing structural units derived from the conjugated diene, and is preferably a block copolymer containing a block mainly containing structural units derived from styrene and a block mainly containing structural units derived from the conjugated diene. Here, "mainly containing" means that the target block contains 60 mass % or more of the target structural units derived from styrene or the target structural units derived from the conjugated diene.

[0025] Furthermore, the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene may contain, in addition to the structural units derived from styrene and the structural units derived from the conjugated diene, structural units derived from other monomers copolymerizable with styrene and the conjugated diene.

[0026] The content of structural units derived from aromatic vinyl compounds in the block copolymer of an aromatic vinyl compound and a conjugated diene is preferably 2 to 40% by mass, more preferably 3 to 35% by mass, and even more preferably 5 to 30% by mass. When the content of structural units derived from aromatic vinyl compounds in the block copolymer of an aromatic vinyl compound and a conjugated diene is equal to or greater than the above-mentioned lower limit, aggregation of the block copolymer of aromatic vinyl compounds and a conjugated diene tends to be prevented, and the generation of gel tends to be effectively suppressed. Furthermore, when the content of structural units derived from aromatic vinyl compounds in the block copolymer of an aromatic vinyl compound and a conjugated diene is equal to or less than the above-mentioned upper limit, good compatibility between different resins tends to be ensured.

[0027] The content of structural units derived from conjugated dienes in the block copolymer of an aromatic vinyl compound and a conjugated diene is preferably 60 to 98% by mass, more preferably 65 to 97% by mass, and even more preferably 70 to 95% by mass. Having the content of structural units derived from conjugated dienes in the block copolymer of an aromatic vinyl compound and a conjugated diene equal to or greater than the above-mentioned lower limit tends to ensure good compatibility between different resins. Furthermore, having the content of structural units derived from conjugated dienes in the block copolymer of an aromatic vinyl compound and a conjugated diene equal to or less than the above-mentioned upper limit tends to prevent aggregation of the block copolymer of an aromatic vinyl compound and a conjugated diene, thereby effectively suppressing gel formation.

[0028] The content of the structural unit of the aromatic vinyl compound in the block copolymer of an aromatic vinyl compound and a conjugated diene can be measured using a nuclear magnetic resonance (NMR) spectrometer after isolating the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene. The content of the structural unit derived from the aromatic vinyl compound can be controlled by adjusting the amount of the aromatic vinyl compound added in the polymerization step of the block copolymer of an aromatic vinyl compound and a conjugated diene.

[0029] The vinyl bond content of the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene (when the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene is a hydrogenated product, the vinyl bond content before hydrogenation) is preferably 20 to 100 mol % from the viewpoints of the fluidity of the amine-modified block copolymer component of an aromatic vinyl compound and a conjugated diene and compatibility with polyolefin resins. Note that the "vinyl bond content before hydrogenation" refers to the 1,2-bond content (mol %) relative to the total amount of 1,4-bonds (cis and trans) and 1,2-bonds (however, when a 3,4-bond is incorporated into the block copolymer of an aromatic vinyl compound and a conjugated diene that has been amine-modified with a 3,4-bond, this refers to the total amount of 1,2-bonds and 3,4-bonds) resulting from the conjugated diene incorporated into the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene before hydrogenation. The vinyl bond content before hydrogenation of the block containing a structural unit derived from a conjugated diene is more preferably 30 to 90 mol %, and even more preferably 35 to 80 mol %.

[0030] The vinyl bond content in the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene can be measured by isolating the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene and then using a nuclear magnetic resonance (NMR) spectrometer, etc. The vinyl bond content can be controlled within the above-mentioned range by using a Lewis base, such as an ether or an amine, as a vinyl bond amount adjuster (hereinafter referred to as a vinylating agent).

[0031] When the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene is a hydrogenated product, the hydrogenation rate of the block containing structural units derived from the conjugated diene is preferably 0 to 100 mol%, and from the viewpoint of compatibility with polyolefin resins, the hydrogenation rate is preferably greater than 0 mol%. The hydrogenation rate of the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene is preferably 40 to 100 mol%, more preferably 70 to 100 mol%, even more preferably 80 to 100 mol%, and even more preferably 90 to 100 mol%. The hydrogenation rate of the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene can be measured using a nuclear magnetic resonance (NMR) spectrometer or the like. The hydrogenation rate can be controlled within the above numerical range, for example, by adjusting the amount of hydrogen during the hydrogenation step.

[0032] The melt flow rate (MFR: 230°C, load 2.16 kg, in accordance with ISO 1133) of the amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene is preferably in the range of 0.1 to 50 g / 10 min, more preferably in the range of 0.5 to 30 g / 10 min, and even more preferably in the range of 1.0 to 25 g / 10 min, from the viewpoint of processability of the thermoplastic resin composition.

[0033] Amine-modified block copolymers of aromatic vinyl compounds and conjugated dienes are available as commercially available products, including, but not limited to, "TUFTECH (trademark) MP10" manufactured by Asahi Kasei Corporation.

[0034] The amine-modified resin (A) may be used alone or in combination of two or more.

[0035] Specific examples of the amine-modified resin (A) include amine-modified styrene-ethylene-butylene-styrene block copolymer (amine-modified SEBS), amine-modified styrene-butadiene-butylene-styrene block copolymer (amine-modified SBBS), amine-modified hydrogenated styrene-ethylene-butylene-styrene block copolymer (amine-modified HSEBS), amine-modified hydrogenated styrene-butadiene-butylene-styrene block copolymer (amine-modified HSBBS), amine-modified hydrogenated styrene-butadiene copolymer rubber (amine-modified HSBR), amine-modified styrene-butadiene-styrene block copolymer (amine-modified SBS), amine-modified styrene-isoprene-styrene copolymer (amine-modified SIS), and amine-modified styrene-ethylene-propylene-styrene block copolymer (amine-modified SEPS). These can be used alone or in combination of two or more. Among these, amine-modified hydrogenated styrene-butadiene-butylene-styrene block copolymer (amine-modified HSBBS) is preferred because of its excellent compatibility with polyolefin resins when recycled.

[0036] The content of the amine-modified resin (A) in the present thermoplastic resin composition is preferably 65 to 95 mass %, more preferably 70 to 87 mass %, and even more preferably 75 to 85 mass %, relative to the mass of the present thermoplastic resin composition.

[0037] <Copolymer (B) Having Structural Units Derived from Maleic Anhydride> The copolymer (B) having structural units derived from maleic anhydride is a copolymer obtained by copolymerizing maleic anhydride as a raw material monomer with other raw material monomers. Therefore, the copolymer (B) is distinguished from a graft-modified polymer obtained by graft-modifying a polymer by reacting maleic anhydride with the polymer. Examples of the copolymer (B) include an elastomer having structural units derived from maleic anhydride, and a multi-olefin copolymer (B1) having structural units derived from maleic anhydride. These may be used alone or in combination of two or more. Among these, the multi-olefin copolymer (B1) having structural units derived from maleic anhydride is preferred because of its excellent compatibility with polyolefin resins when recycled.

[0038] [Elastomer Having Structural Unit Derived from Maleic Anhydride] Examples of elastomers having structural units derived from maleic anhydride include styrene-based elastomers, polyester-based elastomers, polyurethane-based elastomers, polyamide-based elastomers, and the like, each having a structural unit derived from maleic anhydride.

[0039] [Multi-component olefin copolymer (B1) having structural units derived from maleic anhydride] Examples of the multi-component olefin copolymer (B1) having structural units derived from maleic anhydride include multi-component olefin copolymers containing structural units (X1) derived from a monomer selected from ethylene and an α-olefin having 3 to 10 carbon atoms, and structural units (Z1) derived from maleic anhydride.

[0040] Examples of the monomer that constitutes the structural unit (X1) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, and 4-methyl-1-pentene.

[0041] The content of the structural unit (X1) in the multi-component olefin copolymer (B1) having a structural unit derived from maleic anhydride is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more. When the content of the structural unit (X1) is the above upper limit or less, good compatibility with the mixed resin tends to be ensured.

[0042] Furthermore, the content of the structural unit (Z1) derived from maleic anhydride in the multi-component olefin copolymer (B1) having a structural unit derived from maleic anhydride is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. When the content of the structural unit (Z1) derived from maleic anhydride is not more than the above upper limit, it tends to easily interact with the amine-modified resin (A), improve the compatibility between different resins in the mixed resin, prevent the generation of phase-separated foreign matter (dye deposits), and prevent the generation of gel, thereby improving the transparency of the resulting molded article.

[0043] The multi-component olefin copolymer (B1) containing a structural unit derived from maleic anhydride preferably contains, in addition to the structural unit (X1) and the structural unit (Z1) derived from maleic anhydride, a structural unit (Z2) derived from another monomer, from the viewpoint of improving compatibility between different resins.

[0044] Examples of monomers that constitute the structural unit (Z2) include alkyl acrylates in which the alkyl group has 1 to 8 carbon atoms, such as methyl acrylate and ethyl acrylate; alkyl methacrylates in which the alkyl group has 1 to 8 carbon atoms, such as methyl methacrylate and ethyl methacrylate; and vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and vinyl versatate.

[0045] Specific examples of the multi-olefin copolymer (B1) containing a structural unit derived from maleic anhydride include ethylene-maleic anhydride-methyl acrylate copolymer, ethylene-maleic anhydride-ethyl acrylate copolymer, ethylene-maleic anhydride-methyl methacrylate copolymer, ethylene-maleic anhydride-ethyl methacrylate copolymer, and ethylene-maleic anhydride-vinyl acetate copolymer.

[0046] The melt flow rate (MFR: 190°C, load 2.16 kg) of the copolymer (B) having structural units derived from maleic anhydride is usually 0.01 g / 10 min or more and less than 15 g / 10 min, preferably 0.5 to 10 g / 10 min. Having an MFR in the above range ensures a good balance of viscosities between the copolymer (B) having structural units derived from maleic anhydride and the polyolefin resin (C). As a result, the dispersibility of the EVOH resin (D) tends to be further improved.

[0047] The density of the copolymer (B) having a structural unit derived from maleic anhydride is 0.855 to 0.955 g / cm ３ By ensuring that the content is within the above range, there is a tendency that deterioration in the mechanical properties of the recycled film can be more effectively prevented.

[0048] The content of the copolymer (B) in the present thermoplastic resin composition is preferably 5 to 35 mass%, more preferably 13 to 30 mass%, and even more preferably 15 to 25 mass%, relative to the mass of the present thermoplastic resin composition.

[0049] In addition, in the thermoplastic resin composition, the mass ratio of the amine-modified resin (A) to the copolymer (B), expressed as A / B, is 65 / 35 to 99 / 1, more preferably 68 / 32 to 92 / 8, and even more preferably 70 / 30 to 90 / 10. By having the mass ratio within this range, the compatibility between the different resins is improved, the generation of phase-separated foreign matter (dew deposits) is prevented, the generation of gel and deterioration of color tone are prevented, and the transparency and impact resistance of the resulting molded article are improved.

[0050] [Other Components] The thermoplastic resin composition of the present invention may contain any additives other than the amine-modified resin (A) and the copolymer (B) according to various purposes, as long as the additives do not significantly impair the effects of the present disclosure. The other components may be used alone or in any combination and ratio of two or more.

[0051] Examples of the additives include heat stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, plasticizers, lubricants, fillers, neutralizing agents, rust inhibitors, pigments, etc. These may be used alone or in combination of two or more.

[0052] The total content of these additives in the present thermoplastic resin composition is usually 50% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less.

[0053] [Method for producing thermoplastic resin composition] There are no particular limitations on the method for mixing the components to obtain the thermoplastic resin composition, and the composition can be produced by a production method including mixing the amine-modified resin (A) and the copolymer (B). Specific examples include a method in which the amine-modified resin (A), the copolymer (B), and optional additives are dry-blended all at once and melt-kneaded; and a method in which the amine-modified resin (A), the copolymer (B), and optional additives are previously melt-kneaded, and then the other components are added and further melt-kneaded.

[0054] A specific example of a method for melt-kneading is to mix the components uniformly at a predetermined blending ratio using a Henschel mixer, ribbon blender, V-type blender, or the like, and then knead them using a multi-screw kneading extruder, for example, a twin-screw kneading extruder, TEX25, manufactured by The Japan Steel Works.

[0055] The temperature for melt-kneading each component is usually 100 to 300°C, preferably 120 to 280°C, and more preferably 150 to 250°C.

[0056] [Uses of Thermoplastic Resin Composition] The present thermoplastic resin composition can improve the compatibility of a mixed resin containing different resins, and therefore can be suitably used as a compatibilizer, and can be most suitably used as a compatibilizer for EVOH resins. When the present thermoplastic resin composition is used as a compatibilizer, the mixed resin containing different resins and the present thermoplastic resin composition can be melt-kneaded by a known method to form a resin composition.

[0057] The blending ratio of the mixed resin and the present thermoplastic resin composition is usually 0.1 to 40 parts by mass, preferably 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 2 to 8 parts by mass of the present thermoplastic resin composition per 100 parts by mass of the mixed resin.

[0058] As described above, the thermoplastic resin composition can improve the compatibility of a mixed resin containing different resins, and therefore can reduce the amount of phase-separated foreign matter (seam) generated when the resin composition is pelletized. The amount of phase-separated foreign matter (seam) generated when the resin composition is pelletized is preferably 20 mg or less, more preferably 15 mg or less, even more preferably 10 mg or less, particularly preferably 5 mg or less, and may even be 0 mg per 5 kg of pellets.

[0059] The present thermoplastic resin composition can improve the compatibility between the polyolefin resin and the EVOH resin in particular, and therefore the mixed resin preferably contains a polyolefin resin and an EVOH resin.

[0060] [Polyolefin Resin] Examples of the polyolefin resin (excluding those corresponding to the EVOH resin described below) include polypropylene resins such as polypropylene and propylene-based copolymers obtained by copolymerizing propylene with an α-olefin such as ethylene, 1-butene, 1-hexene, or 4-methyl-1-pentene; polyethylene resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene; and polyethylene resins such as ethylene-based copolymers obtained by copolymerizing ethylene with an α-olefin such as 1-butene, 1-hexene, or 4-methyl-1-pentene; poly(1-butene), poly(4-methyl-1-pentene), etc. One type of polyolefin resin may be used alone, or two or more types may be used in combination. Among these, propylene resins such as polypropylene and propylene-based copolymers, and polyethylene resins such as polyethylene, high-density polyethylene, or ethylene-based copolymers are preferred as the polyolefin resin.

[0061] The melt flow rate (MFR: 190°C or 210°C, load 2.16 kg) of the polyolefin resin is preferably 0.01 to 10 g / 10 min. If the MFR of the polyolefin resin is 0.01 g / 10 min or more, the difference in melt viscosity between the EVOH resin and the polyolefin resin does not become too large, and the dispersibility of the EVOH resin in the resin composition tends to be better. On the other hand, if the MFR of the polyolefin resin is 10 g / 10 min or less, the impact resistance of the resulting molded article tends to be better. The MFR of the polyolefin resin is more preferably 5 g / 10 min or less, even more preferably 3 g / 10 min or less, and particularly preferably 2 g / 10 min or less.

[0062] When the resin composition contains a polyolefin resin, the content of the polyolefin resin is preferably 1 to 99.99 mass%, more preferably 30 to 99.9 mass%, and even more preferably 50 to 99.9 mass%, relative to the mass of the resin composition.

[0063] When the resin composition contains a polyolefin resin, the content of the amine-modified resin (A) is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, still more preferably 0.5 to 10 parts by mass, and particularly preferably 3 to 6 parts by mass, relative to 100 parts by mass of the polyolefin resin.

[0064] When the resin composition contains a polyolefin resin, the content of the copolymer (B) is preferably 0.01 to 50 parts by mass, more preferably 0.05 to 10 parts by mass, still more preferably 0.1 to 5 parts by mass, and particularly preferably 0.2 to 3 parts by mass, relative to 100 parts by mass of the polyolefin resin.

[0065] [EVOH Resin] The EVOH resin can be obtained by saponifying an ethylene-vinyl ester copolymer. A typical example of the vinyl ester is vinyl acetate, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can also be used. The ethylene-vinyl ester copolymer can be produced by any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization, and the saponification of the ethylene-vinyl ester copolymer can also be carried out by a known method.

[0066] The ethylene unit content of the EVOH resin is preferably 20 to 60 mol%. If the ethylene unit content is 20 mol% or more, the gas barrier property and melt moldability at high humidity tend to be good. The ethylene unit content of the EVOH resin is more preferably 23 mol% or more. Furthermore, if the ethylene unit content is 60 mol% or less, the barrier property tends to be excellent. The ethylene unit content of the EVOH resin is more preferably 55 mol% or less, and even more preferably 50 mol% or less. The ethylene unit content is usually １ It is measured by H-NMR measurement. For example, １ H-NMR measurement was performed using DMSO-d ６ The measurement method is performed using a thermocouple at a measurement temperature of 50°C.

[0067] The saponification degree of the vinyl ester unit of the EVOH resin is preferably 80 mol% or more, more preferably 98 mol% or more, and even more preferably 99 mol% or more, from the viewpoints of barrier property, thermal stability, and moisture resistance. １ It is measured by H-NMR measurement. For example, １ H-NMR measurement was performed using DMSO-d ６ The measurement method is performed using a thermocouple at a measurement temperature of 50°C.

[0068] The melt flow rate (MFR: 210°C, load 2.16 kg) of the EVOH resin is preferably 0.1 to 100 g / 10 min. If the MFR of the EVOH resin is 100 g / 10 min or less, the difference in melt viscosity between the EVOH resin and the polyolefin resin will not be too large, the dispersibility of the EVOH resin in the resin composition will be better, and the thermal stability will tend to be more excellent. The MFR of the EVOH resin is more preferably 50 g / 10 min or less, and even more preferably 30 g / 10 min or less. On the other hand, if the MFR of the EVOH resin is 0.1 g / 10 min or more, the difference in viscosity from the polyolefin resin will not be too large, and the dispersibility of the EVOH resin in the resin composition will tend to be better. The MFR of the EVOH resin is more preferably 0.5 g / 10 min or more.

[0069] The EVOH resin may be copolymerized with a polymerizable monomer other than ethylene and vinyl ester within a range that does not impair the effects of the present disclosure, generally within a range of 5 mol% or less. Examples of such polymerizable monomers include α-olefins such as propylene, isobutene, α-octene, α-dodecene, and α-octadecene; hydroxyl-containing α-olefins such as 3-butene-1-ol, 4-pentene-1-ol, and 3-butene-1,2-diol, and hydroxyl-containing α-olefin derivatives such as esters and acylates thereof; hydroxymethylvinylidene diacetates such as 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyronyloxy-2-methylenepropane; unsaturated carboxylic acids or salts thereof, partial alkyl esters, complete alkyl esters, nitriles, amides, or anhydrides; unsaturated sulfonic acids or salts thereof; vinylsilane compounds; vinyl chloride; and styrene. These may be used alone or in combination of two or more.

[0070] Furthermore, the EVOH resin may be a "post-modified" EVOH such as urethanized, acetalized, cyanoethylated, or oxyalkylenated. One type of EVOH resin may be used alone, or two or more types may be used in combination.

[0071] When the resin composition contains an EVOH resin, the content of the EVOH resin is preferably 0.01 to 30 mass %, more preferably 0.1 to 15 mass %, and even more preferably 0.5 to 10 mass %, relative to the mass of the resin composition.

[0072] When the resin composition contains a polyolefin resin and an EVOH resin, the content of the EVOH resin is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the polyolefin resin.

[0073] When the resin composition contains an EVOH resin, the mass ratio represented by the content of the amine-modified resin (A) / the content of the EVOH resin is preferably 99 / 1 to 1 / 99, more preferably 90 / 10 to 10 / 90, and even more preferably 70 / 30 to 30 / 70.

[0074] When the resin composition contains an EVOH resin, the mass ratio represented by the content of copolymer (B) / the content of EVOH resin is preferably 99 / 1 to 1 / 99, more preferably 90 / 10 to 10 / 90, and even more preferably 70 / 30 to 30 / 70.

[0075] A suitable method for using the present thermoplastic resin composition as a compatibilizer is, for example, a method comprising melt-kneading the present thermoplastic resin composition with recycled multilayer structures comprising a polyolefin resin layer and an EVOH resin layer. Here, the recycled multilayer structures refer to recycled materials such as scraps, such as burrs, generated during the production of molded articles made of multilayer structures, or rejected products during molding. In the present disclosure, an additive that is blended during melt-kneading of such recycled materials to improve the compatibility between different resins is called a compatibilizer, and the present thermoplastic resin composition is preferably used.

[0076] The resin composition is generally used as at least one layer (regrind layer) of a multilayer structure. Hereinafter, a multilayer structure containing this regrind layer (also simply referred to as a "multilayer structure") will be described.

[0077] [Regrind layer-containing multilayer structure] The regrind layer-containing multilayer structure is sufficient if it has at least one layer containing the resin composition (hereinafter also referred to as "regrind layer" or "Reg layer") in its laminate, and generally, in addition to the regrind layer, it may also contain a polyolefin resin layer (hereinafter also referred to as "PO layer"), an EVOH resin layer, an acid-modified polyolefin resin layer (hereinafter also referred to as "acid-modified PO layer"), etc.

[0078] Specific layer configurations of the Reg layer-containing multilayer structure include, for example, PO layer / Reg layer / acid-modified PO layer / EVOH resin layer, PO layer / Reg layer / acid-modified PO layer / EVOH resin layer / acid-modified PO layer / PO layer, PO layer / Reg layer / acid-modified PO layer / EVOH resin layer / acid-modified PO layer / Reg layer / PO layer, and further, Reg layer / EVOH resin layer, Reg layer / acid-modified PO layer / EVOH resin layer, and Examples include VOH resin layer, Reg layer / acid-modified PO layer / EVOH resin layer / acid-modified PO layer / EVOH resin layer, Reg layer / acid-modified PO layer / EVOH resin layer / acid-modified PO layer / PO layer, Reg layer / acid-modified PO layer / EVOH resin layer / acid-modified PO layer / Reg layer / PO layer, and PO layer / acid-modified PO layer / EVOH resin layer / Reg layer / EVOH resin layer / acid-modified PO layer / PO layer.

[0079] The thickness of each layer of the regrind layer-containing multilayer structure cannot be generally determined depending on the layer configuration, type of polyolefin resin, intended use, container form, required physical properties, etc., but the thickness of the regrind layer is usually 5 to 5,000 μm, preferably 30 to 1,000 μm. The thickness of the EVOH resin layer is usually 5 to 500 μm, preferably 10 to 200 μm. The thickness of the polyolefin resin layer is usually 5 to 5,000 μm, preferably 30 to 1,000 μm. The thickness of the acid-modified PO layer is usually 5 to 400 μm, preferably 10 to 150 μm.

[0080] The thickness ratio of the regrind layer to the polyolefin resin layer is usually 1 / 5 to 10 / 1, and preferably 1 / 2 to 5 / 1. The thickness ratio of the regrind layer to the EVOH resin layer is usually 1 / 1 to 100 / 1, and preferably 5 / 1 to 20 / 1.

[0081] [Method for manufacturing a regrind layer-containing multilayer structure] Such a regrind layer-containing multilayer structure can be manufactured, for example, by molding the same type of resin as the recycled multilayer structure using the same method. In this case, there is no particular limitation on the molding method of the resin composition, and any molding method applicable to general resin compositions can be used. Specifically, the polyolefin resin or EVOH resin can be manufactured by lamination methods such as extrusion molding, blow molding, injection molding, thermoforming, etc., especially coextrusion molding and coinjection molding, particularly coextrusion molding.

[0082] The regrind layer-containing multilayer structure preferably has a bullet mass of 400 g or more, more preferably 405 g or more, and even more preferably 410 g or more, upon dart impact measured by Method A in accordance with JIS K 7124-1 "Plastic films and sheets - Impact test method using free-falling dart method."

[0083] [Molded Article] The molded article of the present disclosure is obtained by molding the resin composition or multilayer structure.

[0084] Examples of shapes of the molded article of the present disclosure include films, sheets, tapes, cups, trays, tubes, bottles, pipes, filaments, irregular cross-section extrusions, and various irregularly shaped articles.

[0085] The molding method for the molded article is not particularly limited, and any molding method applicable to general resin compositions can be used, such as extrusion molding, blow molding, injection molding, thermoforming, etc.

[0086] Furthermore, in molding, a heat stretching treatment is often performed to improve the physical properties of the molded product or to mold it into a desired container shape. Here, heat stretching refers to the process of uniformly molding a thermally uniformly heated film, sheet, or parison-shaped product into a cup, tray, tube, bottle, or film shape using a chuck, plug, vacuum force, compressed air force, blowing, or the like. Examples of such stretching methods include roll stretching, tenter stretching, tubular stretching, stretch-blow method, vacuum forming, compressed air forming, and vacuum-compressed air forming. Stretching may be either uniaxial or biaxial, and in the case of biaxial stretching, either simultaneous biaxial stretching or sequential biaxial stretching can be used. The stretching temperature is usually 60 to 170°C, and preferably 80 to 160°C.

[0087] The molded products obtained in this manner, whether recycled or re-recycled, are useful as various packaging materials for general foods, seasonings such as mayonnaise and dressings, fermented foods such as miso, oily foods such as salad oil, beverages, etc., cosmetics, pharmaceuticals, etc.

[0088] <Effects> The thermoplastic resin composition contains an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride. Therefore, it is believed that the intermolecular interaction between the primary or secondary amino groups of the amine-modified resin (A) and the maleic anhydride groups of the copolymer (B) improves mechanical strength and exhibits excellent compatibility, thereby achieving the effects of the present invention. Furthermore, the use of the thermoplastic resin composition as a compatibilizer can enhance compatibility, particularly with mixed resins containing polyolefin resins and EVOH resins. This is believed to be due to the improved mechanical strength resulting from the bond between the primary or secondary amino group and the carboxy group, as well as the chemical or intermolecular bond between the carboxy group of the copolymer (B) and the hydroxy group of the EVOH resin. Furthermore, the improved compatibility is due to the intermolecular bond between the hydrophobic moieties of the main chains of the amine-modified resin (A) and the copolymer (B) and the hydrophobic moieties of the polyolefin resin and the EVOH resin, thereby suppressing the formation of phase-separated foreign matter (dye deposits), gel formation, and deterioration in color tone.

[0089] Specific embodiments of the present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples as long as it does not deviate from the gist of the disclosure. Note that the values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present disclosure, and a preferred range may be defined by a combination of the above-mentioned upper or lower limit values ​​and the values ​​in the following examples or values ​​between the examples.

[0090] The materials used in the following Examples, Comparative Examples, and Reference Examples are as follows: [Thermoplastic Resin Composition] <Amine-Modified Resin (A)> A-1: ​​Amine-modified hydrogenated styrene-based thermoplastic elastomer: "Tuftec (registered trademark) MP10" manufactured by Asahi Kasei Corporation, MFR (230°C, load 2.16 kg): 4.0 g / 10 min, density: 0.91 g / cm ３ <Copolymer (B) Having Structural Units Derived from Maleic Anhydride> B1-1: Ethylene-Methyl Acrylate-Maleic Anhydride Copolymer: "Rexpearl (trademark) ET350X" manufactured by Japan Polyethylene Corporation, Methyl Acrylate Content: 23% by mass, MFR (190°C, load 2.16 kg): 12 g / 10 min, Density: 0.947 g / cm ３ B1-2: Ethylene-methyl acrylate-maleic anhydride copolymer: "Rexpearl (trademark) ET530H" manufactured by Japan Polyethylene Corporation, methyl acrylate content: 16% by mass, MFR (190 ° C, load 2.16 kg): 30 g / 10 min, density: 0.945 g / cm ３ <Maleic anhydride graft modified polymer (B')> B'-1: maleic anhydride graft modified polyethylene, MFR (190°C, load 2.16 kg): 2.5 g / 10 min, density: 0.910 g / cm ３ B'-2: Maleic anhydride graft-modified ethylene-octene copolymer: "Retain (trademark) 3000" manufactured by The Dow Chemical Company, MFR: 660 g / 10 min (190 ° C, load 2160 g), density: 0.87 g / cm ３

[0091] [Production of Thermoplastic Resin Compositions] <Examples 1 to 4, Comparative Examples 1 to 7, Reference Example> The amine-modified resin (A) and the copolymer (B) having a structural unit derived from maleic anhydride shown in Table 1 below were blended in the ratio shown in Table 1 to produce the thermoplastic resin compositions of each example.

[0092] In Table 1, "-" means that the component was not blended or that the component was not evaluated.

[0093] [Production of Multilayer Structure] 100 parts by mass of a model composition for a multilayer structure (polyethylene (linear low-density polyethylene (LLDPE) (UF641 manufactured by Japan Polyethylene Corporation, MFR: 2.1 g / 10 min (190°C, load 2160 g))), adhesive resin (maleic anhydride-modified polyolefin resin), and EVOH resin (ethylene unit content 32 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g), saponification degree 99.6 mol%): content (mass %) ratio 90 / 5 / 5) were added to 5 parts by mass of the thermoplastic resin composition of each example and dry-blended (however, in the Reference Example, only the model composition for the multilayer structure was used). The obtained dry-blend composition was melt-extruded (pelletized) using a single-screw extruder to obtain pellets. The pellets obtained above were used to form a single-layer film using a single-screw extruder to obtain a 100 μm single-layer film. The appearance of the obtained film was evaluated.

[0094] [Evaluation of Eye Boom] In the above pelletization, the amount of phase-separated foreign matter (eye boom) generated when 5 kg of the dry blend composition was extruded was quantified. Based on the quantified values, evaluation was performed according to the following evaluation criteria. The results are shown in Table 1. <Evaluation criteria> ・0 mg or more but less than 10 mg: A (excellent) ・10 mg or more but less than 20 mg: B (good) ・20 mg or more but less than 30 mg: C (poor) ・30 mg or more: D (very poor)

[0095] [Evaluation of film appearance] The obtained monolayer films were visually evaluated for the presence or absence of gels according to the following evaluation criteria. The results are shown in Table 1. <Evaluation criteria> - None: No cloudy areas were found on the surface or inside of the monolayer film, confirming that no gels had occurred. - Present: Cloudy areas were found on the surface or inside of the monolayer film, confirming that gels had occurred.

[0096] [Evaluation of Impact Resistance] The impact strength of the multilayer structures of Examples 1 to 4, Comparative Examples 1 to 3 and 7, and Reference Example was measured in an atmosphere of 23°C and 50% RH using a Bakelite dart with a diameter of 38 mm and a mass of 32 g according to Method A in accordance with JIS K 7124-1 "Plastic films and sheets - Impact test method using a free-falling dart" using a No. 613 Dart Impact Tester manufactured by Toyo Seiki Seisaku-sho, Ltd. The measurement results were evaluated according to the following evaluation criteria. The results are shown in Table 1. <Evaluation criteria> 400 g or more: A (excellent) 385 g or more but less than 400 g: B (good) 370 g or more but less than 385 g: C (poor) Less than 370 g: D (very poor)

[0097] [Evaluation of Color Tone Stability] The pellets obtained in the production of the multilayer structure were packed into a cylinder with an inner diameter of 50 mm and a height of 50 mm, and the YI value before heating was measured using a spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd.). The pulverized product was also heat-treated in an oven under air atmosphere at 60°C for 14 days, and the YI value after heating was measured in the same manner. The ratio of the YI value after heating to the YI value before heating (YI increase rate) was calculated and evaluated based on the following evaluation criteria. A larger value means that the resin composition is colored yellow after heating, indicating poorer thermal stability. The results are shown in Table 1. <Evaluation criteria> 150% or less: ◯ (excellent) 151 to 200%: Δ (poor) 200% or more: × (very poor)

[0098]

[0099] The results in Table 1 show that the thermoplastic resin compositions of Examples 1 to 4, which contain an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride, and in which the mass ratio of the amine-modified resin (A) to the copolymer (B) having structural units derived from maleic anhydride is within a specific range, were able to reduce the amount of die buildup and suppress gel formation and deterioration in color tone. Furthermore, some Examples also achieved high impact resistance. On the other hand, the thermoplastic resin compositions of Comparative Examples 1 and 2, which contain a polymer (B) other than the copolymer (B) having structural units derived from maleic anhydride, despite having a mass ratio of the amine-modified resin (A) to the polymer (B) having structural units derived from maleic anhydride within a specific range, were unable to suppress deterioration in color tone. Furthermore, the thermoplastic resin composition of Comparative Example 3, which contains an amine-modified resin (A) but does not contain a copolymer (B) having structural units derived from maleic anhydride, exhibits a high amount of die buildup, insufficient impact resistance, and is unable to suppress deterioration in color tone. Furthermore, it is clear that gels were generated in the thermoplastic resin composition of Comparative Example 4, which contained a copolymer (B) having structural units derived from maleic anhydride but did not contain an amine-modified resin (A), and in the thermoplastic resin composition of Comparative Example 5, which contained a polymer (B) other than the copolymer (B) having structural units derived from maleic anhydride but did not contain an amine-modified resin (A). Furthermore, it is clear that the thermoplastic resin compositions of Comparative Examples 6 and 7, which contained an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride but had a mass ratio of the amine-modified resin (A) to the polymer (B) having structural units derived from maleic anhydride outside a specific range, generated gels in Comparative Example 6, and generated eye boogers and had poor impact resistance in Comparative Example 7. Furthermore, in the Reference Example, it is clear that when neither the amine-modified resin (A) nor the copolymer (B) having structural units derived from maleic anhydride was contained, eye boogers and gels were generated and impact resistance was poor. As described above, the thermoplastic resin composition of the present disclosure can reduce the amount of eye boogers, suppress the generation of gels, and inhibit deterioration of color tone. Furthermore, in some examples, high impact resistance can be obtained at the same time. Therefore, compatibilizers, multilayer structures, methods for producing thermoplastic resin compositions, packages, and food packages containing the same also have excellent effects.

[0100] Although the above examples show specific embodiments of the present invention, the examples are merely illustrative and should not be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

Claims

1. A thermoplastic resin composition comprising an amine-modified resin (A) and a copolymer (B) having structural units derived from maleic anhydride, wherein the mass ratio of the amine-modified resin (A) to the copolymer (B) having structural units derived from maleic anhydride, expressed as A / B, is 65 / 35 to 99 / 1.

2. The thermoplastic resin composition according to claim 1, wherein the amine-modified resin (A) is an amine-modified elastomer.

3. The thermoplastic resin composition according to claim 1, wherein the amine-modified resin (A) is an amine-modified block copolymer of an aromatic vinyl compound and a conjugated diene.

4. The thermoplastic resin composition according to claim 1, wherein the copolymer (B) having structural units derived from maleic anhydride is a multi-component olefin copolymer (B1) having structural units derived from maleic anhydride, which comprises structural units (X1) derived from a monomer selected from ethylene and an α-olefin having 3 to 10 carbon atoms, and structural units (Z1) derived from maleic anhydride.

5. A compatibilizer comprising the thermoplastic resin composition according to any one of claims 1 to 4.

6. A multilayer structure having a layer containing the thermoplastic resin composition according to any one of claims 1 to 4.

7. The multilayer structure according to claim 6, wherein the layer comprising the thermoplastic resin composition further comprises a polyolefin resin.

8. A method for producing the thermoplastic resin composition according to any one of claims 1 to 4, comprising mixing the amine-modified resin (A) with the copolymer (B) having structural units derived from maleic anhydride.

9. A package comprising the multilayer structure of claim 6.

10. A food package comprising the multilayer structure of claim 6.

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