Resin composition, molded article, modifier for ABS resin, method for producing resin composition, and method for modifying ABS resin

Abstract

The present invention provides, as a resin composition capable of improving the oil resistance of a molded article, a resin composition that contains an ABS resin (A) and an ethylene-vinyl alcohol resin (B), wherein the ethylene-vinyl alcohol resin (B) contains a modified ethylene-vinyl alcohol resin (B1) that has a structural unit represented by chemical formula (1).

Description

Resin composition, molded product, modifier for ABS resin, method for producing resin composition, and method for modifying ABS resin

[0001] The present invention relates to a resin composition containing an ABS resin and an ethylene-vinyl alcohol-based resin, and more particularly to a resin composition that can be formed into a molded article having excellent oil resistance, a molded article, a method for producing the resin composition, a modifier for ABS resin used therein, and a method for modifying an ABS resin.

[0002] 2. Description of the Related Art ABS resins have been widely used in various industrial fields, including the automobile industry, due to their excellent processability and mechanical properties such as impact resistance.

[0003] In recent years, the need for ABS resins has expanded to include applications in a variety of environments, and various proposals have been made to further improve the physical properties of molded articles made from ABS resins.

[0004] For example, in order to improve the physical properties of molded articles made of ABS resin and to obtain molded articles with excellent antistatic properties and transparency, a technique has been proposed in which an antistatic agent made of polyether ester amide and an acid-modified methacrylic acid polymer are blended with the ABS resin (see Patent Document 1).

[0005] JP 2015-196809 A

[0006] As described above, ABS resins have excellent mechanical properties and are widely used in various industrial fields, but they have the problem of being poor in oil resistance and limiting their applications.

[0007] The present invention has been made in view of the above circumstances, and provides a resin composition capable of improving the oil resistance of a molded article, a molded article thereof, a method for producing the resin composition, an ABS resin modifier to be used therein, and a method for modifying an ABS resin.

[0008] However, the present inventors have conducted extensive research into methods for modifying resin compositions containing ABS resin to improve the oil resistance of molded articles made from such compositions. As a result, they have found that blending a specific modified ethylene-vinyl alcohol resin with the ABS resin improves the oil resistance of molded articles. The present inventors have also found that, for resin compositions containing ABS resin and ethylene-vinyl alcohol resins, the oil resistance of molded articles can be improved by setting the mass change rate in an immersion test within a specific range. Furthermore, they have found that the oil resistance of molded articles formed from resin compositions containing ABS resin and ethylene-vinyl alcohol resins can be improved by setting the contact angle within a specific range.

[0009] That is, the present invention provides the following [1] to

[12] .

[0010] [1] A resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol-based resin (B), wherein the ethylene-vinyl alcohol-based resin (B) contains a modified ethylene-vinyl alcohol-based resin (B1) having a structural unit represented by the following chemical formula (1): [2] A resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol-based resin (B), wherein the mass change rate in the following immersion test is 0.45% or less. [Immersion test] The mass (W1) of a test piece of the resin composition measuring 80 mm in length, 10 mm in width, and 4 mm in thickness is measured. Next, the test piece is immersed in a test oil (Daphne Super Gear Oil 150, manufactured by Idemitsu Kosan Co., Ltd.) at 23°C for 168 hours, and then the test oil is wiped off, and the mass (W2) of the test piece is measured, and the mass change rate (%) is calculated using the following formula: Mass change rate (%) = (W2 - W1) / W1 × 100 [3] The resin composition according to [1] or [2], wherein the content of the ethylene-vinyl alcohol-based resin (B) is 1 to 70 parts by mass per 100 parts by mass of the total of the ABS resin (A) and the ethylene-vinyl alcohol-based resin (B). [4] The resin composition according to [1] or [2], wherein the content of the ethylene-vinyl alcohol-based resin (B) is 1 to 40 parts by mass per 100 parts by mass of the total of the ABS resin (A) and the ethylene-vinyl alcohol-based resin (B). [5] The resin composition according to any one of [1], [3], and [4], wherein the modification rate of the modified ethylene-vinyl alcohol-based resin (B1) having the structural unit represented by chemical formula (1) is 0.1 to 30 mol %. [6] The resin composition according to any one of [1] and [3] to [5], wherein the modified ethylene-vinyl alcohol-based resin (B1) having the structural unit represented by chemical formula (1) is a ring-opening polymer of a lactone ring having 3 to 10 carbon atoms constituting the ring. [7] A molded product comprising the resin composition according to any one of [1] to [6]. [8] The molded product according to [7], wherein the molded product is a sheet or film. [9] A modifier for ABS resins comprising a modified ethylene-vinyl alcohol-based resin (B1) having a structural unit represented by the following chemical formula (1):

[10] A method for producing a resin composition, comprising a step of incorporating a modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1) into an ABS resin (A):

[11] A method for modifying an ABS resin, comprising a step of incorporating a modified ethylene-vinyl alcohol resin having a structural unit represented by the following chemical formula (1) into an ABS resin (A):

[12] A molded product formed from a resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol-based resin (B), wherein the contact angle of the molded product is less than 85°.

[0011] The present invention can provide a resin composition having improved oil resistance and a molded article containing the resin composition.

[0012] Furthermore, according to the modifier for ABS resin and the method for modifying an ABS resin of the present invention, by incorporating the modifier into the ABS resin, it is possible to provide an ABS resin having the above-mentioned excellent physical properties.

[0013] Hereinafter, specific embodiments for carrying out the present invention will be described, but the present invention is not limited to these descriptions. In the present invention, when "X to Y" (X and Y are arbitrary numbers) is expressed, unless otherwise specified, it means "X or more and Y or less," as well as "preferably greater than X" or "preferably smaller than Y." Furthermore, when "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number) is expressed, it also means "preferably greater than X" or "preferably less than Y." Furthermore, "X and / or Y (X and Y are arbitrary components)" means at least one of X and Y, and can mean three possibilities: X only, Y only, or X and Y. In the present invention, the term "main component" refers to a component that has a significant effect on the properties of the material. The content of the component is usually 50% by mass or more of the entire material, preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0014] <Resin Composition According to First Embodiment> First, the resin composition according to the first embodiment of the present invention is a resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol-based resin (hereinafter referred to as "EVOH") (B), in which the EVOH (B) contains a modified EVOH (B1) having a structural unit represented by the following chemical formula (1):

[0015] These will be explained in order below.

[0016] [ABS Resin (A)] The ABS resin (A) used in the present invention is not particularly limited, and any ABS resin containing the three components acrylonitrile, butadiene, and styrene can be used, including commercially available ABS resins. Examples of ABS resin (A) include a type in which acrylonitrile and styrene are grafted onto butadiene latex, a blend of nitrile rubber (NBR), which is a copolymer of acrylonitrile and butadiene, with a copolymer of acrylonitrile and styrene, a copolymer obtained by block or graft polymerization of one or more monomers, such as an aromatic vinyl monomer and a vinyl cyanide monomer, onto a diene rubber, and blends of such copolymers. The diene rubbers referred to here include polybutadiene, polyisoprene, acrylonitrile-butadiene copolymers, styrene-butadiene copolymers, etc., and examples of aromatic vinyl monomers include styrene, α-methylstyrene, and various alkyl-substituted styrenes. Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, and various halogen-substituted acrylonitriles. Specific examples of the above-mentioned copolymers and blends thereof include acrylonitrile-butadiene-styrene terpolymers and acrylonitrile-styrene binary copolymers polymer alloyed with polybutadiene. There are no particular limitations on the composition ratio of the three monomers constituting the ABS resin (A).

[0017] [EVOH (B)] Next, the EVOH (B) used together with the ABS resin (A) will be described.

[0018] The EVOH (B) is a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and a vinyl ester monomer, and is a water-insoluble thermoplastic resin.

[0019] The polymerization of ethylene with a vinyl ester monomer can be carried out by any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization, and solution polymerization using methanol as a solvent is generally used. The resulting ethylene-vinyl ester copolymer can also be saponified by a known method.

[0020] The EVOH (B) produced in this manner is mainly composed of structural units derived from ethylene and vinyl alcohol structural units, and usually contains a small amount of vinyl ester structural units that remain unsaponified.

[0021] Vinyl acetate is typically used as the vinyl ester monomer because of its commercial availability and the efficiency of impurity removal during production. Other vinyl ester monomers include, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate, and aromatic vinyl esters such as vinyl benzoate. Typically, aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms can be used. These can be used alone or in combination of two or more types.

[0022] The content of ethylene structural units in the EVOH (B) can be controlled by the ethylene pressure when copolymerizing the vinyl ester monomer with ethylene, and is usually 20 to 60 mol %, preferably 25 to 50 mol %, and particularly preferably 30 to 45 mol %. If the content is too low, melt moldability tends to decrease. Conversely, if the content is too high, gas barrier properties tend to decrease. The content of ethylene structural units can be measured in accordance with ISO 14663.

[0023] The degree of saponification of the vinyl ester component in the EVOH (B) can be controlled by the amount, temperature, time, etc. of the saponification catalyst (usually an alkaline catalyst such as sodium hydroxide is used) used when saponifying the ethylene-vinyl ester copolymer, and is usually 90 to 100 mol%, preferably 95 to 100 mol%, and particularly preferably 99 to 100 mol%. If the saponification degree is too low, the gas barrier properties, thermal stability, moisture resistance, etc. tend to decrease. The saponification degree of the EVOH (B) can be measured in accordance with JIS K6726 (however, the EVOH is used as a solution uniformly dissolved in a water / methanol solvent).

[0024] The EVOH (B) may further contain structural units derived from the comonomers shown below within a range that does not impair the effects of the present invention (for example, 10 mol % or less of the EVOH).Examples of the comonomer include olefins such as propylene, 1-butene, and isobutene; hydroxyl group-containing α-olefins such as 3-butene-1-ol, 3-butene-1,2-diol, 4-pentene-1-ol, and 5-hexene-1,2-diol, and derivatives thereof such as esters and acylation products; hydroxyalkylvinylidenes such as 2-methylenepropane-1,3-diol and 3-methylenepentane-1,5-diol; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyryloxy-2-methylenepropane. -Hydroxyalkylvinylidene diacetates such as 2-methylenepropane; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, or their salts or mono- or di-alkyl esters in which the alkyl group has 1 to 18 carbon atoms; acrylamide, N-alkylacrylamide in which the alkyl group has 1 to 18 carbon atoms, N,N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salt, acrylamidopropyldimethylamine or its acid salt or its quaternary salt, etc. acrylamides such as methacrylamide, N-alkylmethacrylamides in which the alkyl group has 1 to 18 carbon atoms, N,N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidepropyldimethylamine or an acid salt or a quaternary salt thereof, and the like; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; alkyl vinyl ethers in which the alkyl group has 1 to 18 carbon atoms, hydrochlorides, and the like. vinyl ethers such as alkoxyalkyl vinyl ether and alkoxyalkyl vinyl ether; halogenated vinyl compounds such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride and vinyl bromide; vinyl silanes such as trimethoxyvinylsilane; halogenated allyl compounds such as allyl acetate and allyl chloride; allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; and comonomers such as trimethyl-(3-acrylamido-3-dimethylpropyl)-ammonium chloride and acrylamido-2-methylpropanesulfonic acid.These may be used alone or in combination of two or more.

[0025] In particular, EVOH having a primary hydroxyl group in the side chain is preferred because it has good secondary formability in stretching treatment and vacuum / pressure molding, and among these, EVOH having a 1,2-diol structure in the side chain is preferred.

[0026] The EVOH (B) used in the present invention may be "post-modified" such as urethanized, acetalized, cyanoethylated, oxyalkylenated, or acylated.

[0027] Furthermore, the EVOH (B) used in the present invention may be a mixture with a different EVOH. Examples of such other EVOH include EVOHs having a different degree of saponification, a different degree of polymerization, or a different copolymerization component.

[0028] [Modified EVOH (B1)] The resin composition according to the first embodiment of the present invention contains, as EVOH (B), a modified EVOH (B1) having a structural unit represented by the following chemical formula (1). EVOH (B) may contain an EVOH other than modified EVOH (B1), but from the viewpoint of the effects of the present invention, it is preferable that EVOH (B) is modified EVOH (B1). The modified EVOH (B1) will be described below.

[0029]

[0030] The modified EVOH (B1) used in the first embodiment of the present invention has a structural unit represented by the above chemical formula (1) in the main chain.

[0031] In the above chemical formula (1), X represents an organic chain having a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, and a silicon atom. Among these, from an industrial viewpoint, the heteroatom is preferably an oxygen atom, a nitrogen atom, or a sulfur atom, and particularly preferably an oxygen atom.

[0032] From the viewpoint of production, X is preferably an organic chain having a hydrocarbon chain which may have a substituent and which has a carbonyl group as the starting point and a heteroatom which may have a substituent at the repeating end. X may also have other heteroatoms as long as it has a heteroatom at least at the repeating end, which has a carbonyl group as the starting point.

[0033] The above X is an organic chain having a hydrocarbon chain which may have a substituent and a heteroatom which may have a substituent at a repeating terminal, and the hydrocarbon chain which may have a substituent is R x When the heteroatom which may have a substituent and which is located at the repeating end is Z, it is represented by the following chemical formula (2).

[0034]

[0035] In the chemical formula (2), when Z is an oxygen atom, the repeating unit is -CO-R x When Z is a nitrogen atom, the repeating unit is —CO—R x -NH-, -CO-R x -NR 3 When Z is a sulfur atom, the repeating unit is —CO—R x Examples of the substituents that the hydrocarbon and heteroatom may have include alkyl groups such as methyl groups and ethyl groups, aryl groups such as aromatic rings, and acyl groups such as acetyl groups. x -NR 3 R in - 3 represents an alkyl group such as a methyl group or an ethyl group, an aryl group such as an aromatic ring, or an acyl group such as an acetyl group. Among these, from the viewpoint of improving gas barrier properties, the repeating unit is preferably —CO—R x -O-, -CO-R x -NH- or -CO-R x -S- is preferred, and it is particularly preferred that Z is an oxygen atom. Specifically, it is preferred to contain an aliphatic polyester unit represented by the following chemical formula (3).

[0036]

[0037] The hydrocarbon chain R in the chemical formulas (2) and (3) x is preferably a straight or branched chain having 1 to 10 carbon atoms. Examples of the straight or branched hydrocarbon chain having 1 to 10 carbon atoms include a methylene group (-CH2-), a methine group (-CHR-), a quaternary carbon group having no hydrogen atom (-CR 1 R 2 -), propylene group, isopropylene group, butylene group, isobutylene group, phenylene group, etc. 1 , R 2 represents an alkyl group such as a methyl group or an ethyl group, or an aryl group such as an aromatic ring. Of these, the hydrocarbon chain is more preferably a linear or branched alkyl chain having 2 to 8 carbon atoms, and even more preferably a linear or branched alkyl chain having 3 to 7 carbon atoms. Of these, from the viewpoint of improving the storage stability and processing stability of the resin, a linear hydrocarbon chain is preferred, a linear alkyl chain having 2 to 8 carbon atoms is more preferred, and a linear alkyl chain having 3 to 7 carbon atoms is particularly preferred.

[0038] In chemical formulas (1) to (3), n represents a positive integer. n is preferably an integer of 1 to 20, and more preferably an integer of 1 to 10. If n is too large, the barrier properties tend to decrease, so n is preferably an integer of 20 or less.

[0039] In the chemical formula (1), when n is 2 or more, the multiple Xs may be the same or different, but are preferably the same from the viewpoint of barrier properties. x In the chemical formula (3), when n is 2 or more, a plurality of R x may be the same or different, but are preferably the same from the viewpoint of barrier properties.

[0040] In the resin composition according to the first embodiment of the present invention, the average value of n in the chemical formulas (1) to (3) in the modified EVOH (B1) (i.e., sometimes referred to as the average chain length of the graft chains) is preferably in the range of 1 to 10, more preferably in the range of 1 to 5, even more preferably in the range of 1 to 2, and particularly preferably in the range of 1 to 1.5. If the average value of n becomes too large, the variation in the chain length of the graft chains increases, which tends to result in a decrease in gas barrier properties, so it is preferably 10 or less.

[0041] The structural units represented by the chemical formulas (1) to (3) can be identified by common organic chemistry techniques such as nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy, mass spectrometry, etc. The average chain length of the graft chains in the chemical formulas (1) to (3) in the modified EVOH (B1) of this embodiment is 1 It can be calculated from the results of H-NMR measurement.

[0042] [Method for Producing Modified EVOH (B1)] Modified EVOH (B1) having a structural unit represented by chemical formula (1) in its main chain can be obtained, for example, by grafting EVOH and a compound having a heterofunctional group in a molten state of EVOH in a stirred tank-type production apparatus equipped with a stirring blade while heating and stirring, or by using an extruder, a shear molding machine equipped with a feedback screw, etc. The repeating unit consisting of chemical formula (1) in the main chain of modified EVOH (B1), i.e., the formation of a side-chain graft structure by graft reaction, begins at the initiation terminal of the hydroxyl group of EVOH.

[0043] [Compound Having a Heterofunctional Group] A heterofunctional group is a functional group having a heteroatom, and examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, and a silicon atom. Specific examples of the functional group having a heteroatom include an ester group, a carboxylic acid group, an acyl group, a thioester group, an amide group, a carbonate group, a carbamate group, a thiocarbamate group, a carbamide group, an N-acyl group, and an N,N'-diacyl group.

[0044] Examples of compounds having a heterofunctional group include cyclic compounds having a heterofunctional group, carboxylic acid compounds, carbonate compounds, carbamate compounds, thiocarbamate compounds, diacyl compounds, triacyl compounds, and analogs thereof. Of these, cyclic compounds having a heterofunctional group are preferred.

[0045] [Cyclic Compound Having Heterofunctional Group] The cyclic compound having a heterofunctional group is preferably a heterocyclic compound having 2 or more carbon atoms. Examples of the cyclic compound having a heterofunctional group include cyclic esters such as lactones, cyclic amides such as lactams, cyclic carbonates such as ethylene carbonate and propylene carbonate, cyclic thioesters such as thietan-2-one, 3,3-dimethylthietan-2-one, 4-methylthietan-2-one, 3-methylthietan-2-one, 3-ethylthietan-2-one, and 3-methyl-3-ethylthietan-2-one, cyclic carbamates such as ethylene carbamate, imide compounds such as phenylphthalimide and cyclohexanedicarboximide, cyclic urea derivatives such as N,N'-dimethylpropyleneurea and 1,3-dimethyl-2-imidazolidinone, and cyclic N,N'-diacyl compounds such as N-acyl-substituted caprolactam. Among these, cyclic esters are preferred, and lactones are more preferred.

[0046] The lactones are preferably lactones having 3 to 10 carbon atoms constituting the ring that forms the aliphatic polyester by ring-opening polymerization. When such lactones have no substituent, they are represented by the following general formula (4):

[0047]

[0048] In the above formula (4), n is an integer of 2 to 9, and preferably n is 4 to 5. In addition, the alkylene chain —(CH) in the above formula (4) n Any of the carbon atoms may have at least one substituent such as a lower alkyl group having about 1 to 8 carbon atoms, a lower alkoxy group, a cycloalkyl group, a phenyl group, or an aralkyl group.

[0049] Specific examples of such lactones include β-propionolactones, γ-butyrolactones, ε-caprolactones, and δ-valerolactones.

[0050] Examples of the β-propionolactones include β-propionolactone and dimethylpropionolactone.

[0051] Examples of the γ-butyrolactones include butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprylolactone, γ-laurolactone, γ-palmitolactone, γ-stearolactone, crotonolactone, α-angelicalactone, and β-angelicalactone.

[0052] Examples of the ε-caprolactones include monoalkyl-ε-caprolactones such as ε-caprolactone, monomethyl-ε-caprolactone, monoethyl-ε-caprolactone, monodecyl-ε-caprolactone, monopropyl-ε-caprolactone, and monodecyl-ε-caprolactone; dialkyl-ε-caprolactones in which two alkyl groups are substituted on carbon atoms other than the ε position; trialkyl-ε-caprolactones in which three alkyl groups are substituted on carbon atoms other than the ε position; alkoxy-ε-caprolactones such as ethoxy-ε-caprolactone; cycloalkyl-lactones such as cyclohexyl-ε-caprolactone; aralkyl-ε-caprolactones such as benzyl-ε-caprolactone; and aryl-ε-caprolactones such as phenyl-ε-caprolactone.

[0053] Examples of the δ-valerolactones include 5-valerolactone, 3-methyl-5-valerolactone, 3,3-dimethyl-5-valerolactone, 2-methyl-5-valerolactone, and 3-ethyl-5-valerolactone.

[0054] These lactones can be used alone or in combination of two or more.

[0055] Among these, ε-caprolactones and δ-valerolactones are particularly preferred, with ε-caprolactone being particularly preferred because it is inexpensive and easily available.

[0056] [Carboxylic Acid Compound] Examples of the carboxylic acid compound include linear carboxylic acid esters, linear carboxylic acid thioesters, linear carboxylic acid amides, acyl halides of carboxylic acids, acid anhydrides, etc. Among these, linear carboxylic acid esters are preferred.

[0057] [Carbonate Compound] Examples of the carbonate compound include various dialkyl carbonates, diaryl carbonates, and aryl alkyl carbonates.

[0058] [Carbamate Compound] Examples of the carbamate compound include methyl carbamate and ethyl carbamate.

[0059] [Thiocarbamate Compound] Examples of the thiocarbamate compound include derivatives such as dimethylamino-S-arylthiocarbamate.

[0060] [Diacyl Compound] Examples of the diacyl compound include diacetamide and diacetyl(cyclopentyl)azane.

[0061] [Triacyl Compound] Examples of the triacyl compound include triacetamide and tribenzamide.

[0062] Other compounds having a heterofunctional group include oligomers or polymers of the repeating structural units represented by n in chemical formulas (1) to (3). For example, polyesters such as poly-ε-caprolactone and polylactic acid, polyamides such as poly-ε-caprolactam, and polythioesters can be used.

[0063] As described above, the modified EVOH (B1) having a structural unit represented by chemical formula (1) can be produced by melt-kneading EVOH and a compound having a heterofunctional group in a molten state of EVOH while heating and stirring in a stirred tank-type production apparatus equipped with stirring blades, or by using an extruder, a shear molding machine equipped with a feedback screw, or the like.

[0064] For example, when a cyclic compound having a heterofunctional group is used as the compound having a heterofunctional group, a modified EVOH (B1) having a structural unit represented by chemical formula (1) in its main chain can be produced by carrying out a ring-opening polymerization reaction of the cyclic compound having a heterofunctional group and a graft reaction in the presence of EVOH. On the other hand, when a carboxylic acid compound is used as the compound having a heterofunctional group, a modified EVOH (B1) having a structural unit represented by chemical formula (1) in its main chain can be produced by carrying out a nucleophilic substitution reaction or dehydration condensation reaction of the carboxylic acid compound and a graft reaction in the presence of EVOH.

[0065] Among these, the modified EVOH (B1) is preferably an EVOH containing an aliphatic polyester unit (aliphatic polyester-modified EVOH), which is a ring-opening polymer of a lactone ring having 3 to 10 carbon atoms constituting the ring.

[0066] In the case of the reaction involving ring-opening polymerization, it is preferable to add a conventionally known ring-opening polymerization catalyst. Examples of ring-opening polymerization catalysts include titanium-based compounds and tin-based compounds. Specific examples include titanium alkoxides such as tetra-n-butoxytitanium, tetraisobutoxytitanium, and tetraisopropoxytitanium; tin alkoxides such as dibutyldibutoxytin; and tin ester compounds such as tin 2-ethylhexanoate and dibutyltin diacetate. Among these, tetra-n-butoxytitanium and tin 2-ethylhexanoate are preferred because they are inexpensive and easily available.

[0067] The reaction can also be carried out in a heated, molten state in a kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a Brabender.

[0068] The reaction time and temperature in the ring-opening polymerization are not particularly limited and may be selected appropriately, but are preferably carried out at 50 to 250°C for 10 seconds to 24 hours with stirring, and more preferably at 150 to 230°C for 50 seconds to 10 hours with stirring. If the reaction time is shorter than the lower limit or the reaction temperature is lower than the lower limit, the reaction rate decreases, which tends to cause unreacted compounds to bleed out from the molded product, resulting in deterioration of the surface appearance. If the reaction time is longer than the upper limit or the reaction temperature is higher than the upper limit, crosslinking occurs between the modified EVOH molecules, which tends to cause poor appearance of the molded product, such as fisheyes.

[0069] In the modified EVOH (B1) obtained in this manner, the content of the EVOH units forming the main chain of the modified EVOH (B1) is usually 40 to 99% by mass, preferably 45 to 95% by mass, and particularly preferably 50 to 90% by mass. The content of the structural unit represented by any one of chemical formulas (1) to (3) grafted to the main chain is usually 1 to 60% by mass, preferably 5 to 55% by mass, and particularly preferably 10 to 50% by mass. If the content of the EVOH units is too high, the mechanical strength, particularly the tensile break strain, will not improve and compatibility with the ABS resin (A) will decrease, tending to prevent the effects of the present invention from being achieved. On the other hand, if the amount of the EVOH units is too low, the adhesiveness will be strong and blocking of the molded product will be more likely to occur. The contents of the EVOH units and the structural units represented by any one of chemical formulas (1) to (3) in the modified EVOH (B1) are as follows: 1 It can be calculated from the results of H-NMR measurement.

[0070] The number average molecular weight of the modified EVOH (B1) (measured by GPC in terms of standard polystyrene) is usually 5,000 to 300,000, preferably 10,000 to 200,000, and particularly preferably 10,000 to 100,000. If the number average molecular weight of the modified EVOH (B) is too high, its melt viscosity will be too high, and its dispersibility in the ABS resin (A), which is the main component, will tend to decrease. On the other hand, if the number average molecular weight of the modified EVOH (B1) is too low, its melt viscosity will be too low, and stable melt molding will tend to be difficult. The number average molecular weight of the modified EVOH (B1) can be calculated from the results of GPC measurement.

[0071] The modification rate of the modified EVOH (B1) is usually 0.1 to 30 mol%, more preferably 1 to 25 mol%, and particularly preferably 5 to 20 mol%. If the modification rate is too low, the oil resistance as a modifier will be poor and the compatibility with the ABS resin (A) will be reduced, so that the effects of the present invention will not be obtained. On the other hand, if the modification rate is too high, the adhesiveness will be strong and blocking of the molded product will be likely to occur. The modification rate is 1 It can be calculated from the results of H-NMR measurement.

[0072] Furthermore, the average value of n in the chemical formulas (1) to (3) in the modified EVOH (B1) (i.e., the average chain length of the graft chains) is usually 1 to 15, preferably 1 to 10, and particularly preferably 1 to 8. If the average chain length of the graft chains is too long, the tackiness tends to be strong and blocking of the molded product tends to occur. The average chain length of the graft chains is 1 It can be calculated from the results of H-NMR measurement.

[0073] Specifically, under the following conditions: 1 By measuring H-NMR, the modification rate and the average chain length of the grafted chains in the modified EVOH (B1) can be calculated. 1H-NMR measurement conditions: Internal standard substance: tetramethylsilane; Solvent: d6-DMSO; Polymer concentration measured: 5% by mass (0.1 g sample, 2 mL solvent); Measurement temperature: 50°C (323 K); Irradiation pulse: 45° pulse; Pulse interval: 10 sec; Number of accumulations: 16 (b) Assignment of resonance absorption peaks (I) 0.8 to 0.9 ppm: -CH3 at the terminal of modified EVOH (II) 1.0 to 1.9 ppm: -CH2- at the main chain of modified EVOH and -CH2- adjacent to each other in graft chains (III) 2.0 ppm: -CH3 of the residual acetyl group of modified EVOH (IV) 2.1 to 2.3 ppm: -CH2- adjacent to the carboxy group in the graft chain (V) 3.3 to 4.0 ppm: -CH- adjacent to -OH in the modified EVOH, and -CH2- adjacent to -OH in the graft chain (VI) 4.0 to 4.7 ppm: -OH in the modified EVOH and the graft chain, and -CH2- adjacent to the ester bond in the graft chain (c) Calculation of Modification Rate and Average Chain Length Using the integral values ​​of the resonance absorption peaks of (I) to (VI) above, the following simultaneous equations (i) to (vi) were established, and the amount of modifying groups C (mol) and the average chain length n (mol) of the graft chains were calculated from the solutions of the simultaneous equations. Furthermore, the modification rate X (mol %) was calculated from equation (vii). Formula (i): 3 × M = [Integral value of peak (I)] Formula (ii): (2 × M) + (2 × A) + (4 × E) + (2 × O) + (6 × n + 2) × C = [Integral value of peak (II)] Formula (iii): 3 × A = [Integral value of peak (III)] Formula (vi): 2 × n × C = [Integral value of peak (IV)] Formula (v): O + (2 × C) = [Integral value of peak (V)] Formula (vi): O + (2 × n - 1) × C = [Integral value of peak (VI)] Formula (vii): X = C / (M + A + O + C + E) × 100 Here, M, A, O, C, n, E, and X represent the following values. M: Amount (mol) of terminal methyl groups in modified EVOH; A: Amount (mol) of acetyl groups in modified EVOH; O: Amount (mol) of hydroxyl groups in modified EVOH; C: Amount (mol) of modifying groups in modified EVOH; n: Average chain length of graft chains (number); E: Amount (mol) of ethylene groups in modified EVOH; X: Modification rate (mol %) of modified EVOH

[0074] The glass transition temperature (Tg) of the modified EVOH (B1) is usually −50 to 60° C., preferably −30 to 45° C., and particularly preferably −10 to 35° C. If the glass transition temperature is too low, blocking of the molded product tends to occur, while if the glass transition temperature is too high, the effects of the present invention tend not to be obtained. The glass transition temperature can be measured using a differential scanning calorimeter.

[0075] Specifically, the glass transition temperature of modified EVOH (B1) can be calculated by measurement using a differential scanning calorimeter under the following conditions: (a) Conditioning of test piece: After melting at 230°C for 1 minute, the sample is cooled to -30°C at a cooling rate of 10°C / min. (b) Analysis of glass transition temperature: The sample cooled in (a) is heated to 230°C at a heating rate of 10°C / min. (c) Calculation of glass transition temperature: From the DSC curve obtained in (b), the midpoint temperature of the stepwise change in the glass transition is calculated as the glass transition temperature.

[0076] The MFR (melt flow rate) of the modified EVOH (B1) is usually 0.5 to 100 g / 10 min, preferably 1 to 50 g / 10 min, and particularly preferably 3 to 35 g / 10 min. If the MFR is too high, the melt viscosity of the modified EVOH (B1) may be too low, making stable melt molding difficult. If the MFR is too low, the melt viscosity of the modified EVOH (B1) may be too high, tending to reduce dispersibility in the ABS resin (A). The MFR is an index of the degree of polymerization of the EVOH that forms the main chain of the modified EVOH (B1), and can be adjusted by the amount of polymerization initiator and the amount of solvent used when copolymerizing the monomers.

[0077] <Resin Composition> Next, a resin composition according to a first embodiment of the present invention will be described. The resin composition according to the first embodiment of the present invention contains an ABS resin (A) and an EVOH (B), and the EVOH (B) contains a modified EVOH (B1). The ABS resin (A) is preferably the main component of the resin composition.

[0078] The content of EVOH (B) is not particularly limited, but is preferably 1 to 70 parts by mass per 100 parts by mass of the total of the ABS resin (A) and the EVOH (B).

[0079] That is, the lower limit of the content of EVOH (B) is preferably 1 part by mass, more preferably 5 parts by mass, and even more preferably 10 parts by mass. The upper limit of the content of EVOH (B) is preferably 70 parts by mass, more preferably 60 parts by mass, even more preferably 50 parts by mass, particularly preferably 40 parts by mass, and especially preferably 20 parts by mass. Among these, the content of EVOH (B) is preferably 1 to 70 parts by mass, more preferably 1 to 40 parts by mass, and even more preferably 1 to 20 parts by mass.

[0080] If the content of EVOH (B) is greater than the above range, the balance of the compatibility between the ABS resin (A) and the EVOH (B) is lost, and the water resistance of the resulting molded product tends to decrease. On the other hand, if the content of EVOH (B) is too small, the modifying effect on the ABS resin (A) tends to be lost.

[0081] The resin composition according to the first embodiment of the present invention may contain, as other components, within a range that does not impair the effects of the present invention (for example, typically 30% by mass or less of the resin composition, preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less), a carboxylic acid-modified polyolefin resin, a hydrocarbon resin having a number-average molecular weight of 100 to 3,000 and a softening point of 60°C or more but less than 170°C, other thermoplastic resins, and additives generally added to EVOH, such as heat stabilizers, antioxidants, antistatic agents, colorants, UV absorbers, lubricants, plasticizers, light stabilizers, surfactants, antibacterial agents, desiccants, antiblocking agents, flame retardants, crosslinking agents, curing agents, foaming agents, crystal nucleating agents, antifogging agents, biodegradable additives, silane coupling agents, oxygen absorbers, etc. These additives may be used alone or in combination of two or more.

[0082] Examples of the heat stabilizer, for the purpose of improving various physical properties such as thermal stability during melt molding, include organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, and behenic acid, and salts thereof such as alkali metal salts (sodium, potassium, and the like), alkaline earth metal salts (calcium, magnesium, and the like), and zinc salts; and inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, and boric acid, and additives thereof such as alkali metal salts (sodium, potassium, and the like), alkaline earth metal salts (calcium, magnesium, and the like), and zinc salts. Among these, boron compounds including acetic acid, boric acid, and salts thereof, acetates, and phosphates are preferably used.

[0083] <Preparation of Resin Composition> Next, a method for obtaining the resin composition according to the first embodiment of the present invention will be described. The resin composition according to the first embodiment of the present invention can be obtained by mixing the ABS resin (A), the modified EVOH (B1) as the EVOH (B), and any optional components that are blended as necessary.

[0084] The mixing method is not particularly limited, and the components can be dry-blended and used directly. Generally, however, the components are mixed by a melt mixing method, a solution mixing method, or the like, and then molded into an easily handleable shape such as pellets to prepare a resin composition. From the viewpoint of productivity, the melt mixing method is preferred.

[0085] The melt mixing method can be a method in which the components are dry-blended and then melted and mixed, or can be carried out using a known kneading device such as a kneader-ruder, extruder, mixing roll, Banbury mixer, or plastomill. However, it is usually industrially preferable to use a single-screw or twin-screw extruder, and it is also preferable to provide a vent suction device, a gear pump device, a screen device, or the like, as necessary.

[0086] The melt-kneading temperature is usually set in the range of 50 to 250° C. as the temperature of the extruder and the die, preferably 100 to 240° C., and particularly preferably 150 to 230° C. If the temperature is too low, the resin tends to be in an unmelted state and the processing state tends to become unstable, whereas if the temperature is too high, the resin composition tends to be thermally deteriorated and the quality of the obtained molded product tends to decrease.

[0087] Furthermore, examples of methods for adding additives such as acetic acid, boron compounds, acetates, and phosphates to a resin composition include: i) a method in which the resin composition is brought into contact with an aqueous solution of the additive to incorporate the additive into the resin composition, and then drying the resulting mixture; and ii) a method in which the resin composition and the additive are mixed together and then melt-kneaded in an extruder or the like.

[0088] It is also possible to blend two or more different types of modified EVOH (B1), or to blend a modified EVOH (B1) with a normal EVOH (B).

[0089] <Resin composition according to a second embodiment> The resin composition according to a second embodiment of the present invention is a resin composition containing an ABS resin (A) and an EVOH (B), and has a mass change rate in an immersion test that is not more than a specific value. Therefore, the resin composition according to the second embodiment of the present invention can improve oil resistance. Furthermore, the resin composition according to the second embodiment of the present invention preferably contains the ABS resin (A) and the EVOH (B) as main components.

[0090] The details of the ABS resin (A) and the EVOH (B) used in the resin composition according to the second embodiment of the present invention have been described above, and therefore will not be described again. The content of EVOH (B), other components, production method, etc. in the resin composition according to the second embodiment of the present invention may be similar to those of the resin composition according to the first embodiment of the present invention.

[0091] The mass change rate in the immersion test is 0.45% or less, preferably 0.30% or less, and particularly preferably 0.20% or less, with the lower limit being 0%. The mass change rate in the immersion test can be determined as follows. [Immersion test] The mass (W1) of a test piece of the resin composition measuring 80 mm in length, 10 mm in width, and 4 mm in thickness is measured. Next, the test piece is immersed in test oil (Daphne Super Gear Oil 150, manufactured by Idemitsu Kosan Co., Ltd.) at 23°C for 168 hours, after which the test oil is removed and the mass (W2) of the test piece is measured, and the mass change rate (%) is calculated using the following formula: Mass change rate (%) = (W2 - W1) / W1 x 100

[0092] To achieve a mass change rate of 0.45% or less for the resin composition according to the second embodiment of the present invention, for example, a method using the modified EVOH (B1) described in connection with the resin composition according to the first embodiment of the present invention, a method using an EVOH (B) having a relatively high content of ethylene structural units of 35 to 60 mol%, or a method using lactones described in connection with the resin composition according to the first embodiment of the present invention can be used. These methods can be used alone or in combination to achieve a mass change rate of 0.45% or less. Of these, the method using the modified EVOH (B1) described in connection with the resin composition according to the first embodiment of the present invention is preferred.

[0093] <Molded Product> Next, a molded product obtained using the resin composition according to the first embodiment or the second embodiment of the present invention, and a molded product formed from a resin composition containing an ABS resin (A) and an EVOH (B), wherein the contact angle of the molded product is less than 85°, will be described.

[0094] The contact angle of the molded product is less than 85°, preferably 83° or less, more preferably 81° or less. By setting the contact angle of the molded product within the above range, a molded product with excellent oil resistance can be obtained. The contact angle of the molded product is measured by conditioning a test piece of the resin composition, 200 mm long x 20 mm wide x 4 mm thick, in an environment of 23°C and 50% RH for 3 days, and then dropping 2 μm of water onto the test piece under measurement conditions of 23°C and 50% RH, and measuring the angle between the water and the test piece 120 seconds after the dropping.

[0095] Examples of methods for making the contact angle of a molded product less than 85° include a method using a modified EVOH (B1) described in connection with the resin composition according to the first embodiment of the present invention, a method using an EVOH (B) having a relatively high content of ethylene structural units, such as 35 to 60 mol%, and a method using lactones described in connection with the resin composition according to the first embodiment of the present invention. The contact angle can be made less than 85° by using these methods alone or in combination. Of these, the method using a modified EVOH (B1) described in connection with the resin composition according to the first embodiment of the present invention is preferred.

[0096] The resin composition is usually provided as a molded product having various shapes according to the purpose, such as a film, a sheet, a container, a fiber, a rod, a tube, etc., by melt molding or the like. Examples of uses thereof include a wide variety of uses, such as packaging materials, fibers, daily necessities, home appliance parts, automobile parts, medical components, and civil engineering and construction materials.

[0097] Molded articles obtained using the resin composition can be used not only as virgin products, but also as crushed products (e.g., when recycled articles are reused) of the molded articles, which can be melt-molded again for reuse. The melt-molding methods mainly used are extrusion molding (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.) and injection molding. The melt-molding temperature is usually in the range of 50 to 250°C, preferably 100 to 240°C, and particularly preferably 150 to 230°C. If the melt-molding temperature is too low, the melt-moldability tends to decrease due to insufficient fluidity, while if the melt-molding temperature is too high, the resin composition tends to thermally deteriorate, resulting in poor appearance such as the occurrence of fisheyes and discoloration.

[0098] When the resin composition is used to form a single layer film or sheet, the thickness thereof will vary depending on the application, but is usually 5 to 2000 μm, preferably 10 to 500 μm, and more preferably 10 to 200 μm.

[0099] Furthermore, when the resin composition is molded into a film or sheet, it can be used not only as a single molded product, but also as a multilayer structure having at least one layer made of the resin composition, which can be molded into various molded products.

[0100] Examples of methods for producing the multilayer structure include a method of melt-extruding a thermoplastic resin onto a film or sheet containing the resin composition, a method of conversely melt-extruding the resin composition onto a substrate such as a thermoplastic resin, a method of co-extruding the resin composition with another thermoplastic resin, and a method of dry-laminating a film or sheet containing the resin composition with a film or sheet of another substrate using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester compound, or a polyurethane compound.

[0101] Among the above methods, the method of co-extruding the resin composition with another thermoplastic resin is preferred because it allows for easy operation management. Examples of the thermoplastic resins to be co-extruded include polyolefin resins, polyester resins, polyamide resins, copolymerized polyamides, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride, acrylic resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, chlorinated polypropylene, aromatic and aliphatic polyketones, and aliphatic polyalcohols. Among these, polyolefin resins are preferred because of their excellent mechanical properties, extrusion processability, and ability to be used in a wide variety of molding processes.

[0102] The polyolefin resin is not particularly limited, but examples thereof include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), very low-density polyethylene (VLDPE), ethylene-vinyl acetate copolymer (EVA), and ionomers, which are preferred in that the resulting laminated packaging material has excellent resistance to bending fatigue, vibration fatigue, and the like.

[0103] When the resin composition is used to obtain a multilayer structure, the layer structure is a (a1, a2, ...) where a layer containing the resin composition is a layer a (a1, a2, ...) and another substrate, for example, a layer made of a thermoplastic resin, is b (b1, b2, ...), and in the form of a film, sheet, bottle, pipe, or tube, not only a two-layer structure of a / b but also any combination such as b / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / b1 / a / b1 / b2, b1 / b2 / a / b3 / b4, or a1 / b1 / a2 / b2 is possible. Furthermore, when a fibrous or filamentous molded product is obtained, the resin composition can be used in combination with another substrate in the same manner, and any combination of a and b is possible, such as a bimetal type, core (a)-sheath (b) type, core (b)-sheath (a) type, or eccentric core-sheath type.

[0104] In the multilayer structure, adhesive resin layers can be provided between the layers as needed. The resin used for the adhesive resin layer cannot be generalized because it varies depending on the type of resin used for the other layers (b), but examples include modified olefin polymers containing carboxy groups obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to an olefin polymer by addition reaction, graft reaction, or the like.

[0105] Specifically, suitable examples include one or a mixture of two or more selected from maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block or random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft-modified ethylene-vinyl acetate copolymer, etc. In this case, the amount of unsaturated carboxylic acid or anhydride contained in the olefin polymer is preferably 0.001 to 3 mass%, more preferably 0.01 to 1 mass%, and particularly preferably 0.03 to 0.5 mass%. If the modification amount in the modified product is low, adhesion tends to be insufficient, while if it is high, crosslinking reaction tends to occur, resulting in poor moldability.

[0106] These adhesive resins can also be blended with the above-mentioned resin composition, other rubber / elastomer components such as EVOH, polyisobutylene, ethylene-propylene rubber, and the resin of the layer b (the layer to be adhered), etc. In particular, it is possible to blend a polyolefin resin different from the base polyolefin resin of the adhesive resin.

[0107] The thickness of each layer of the multilayer structure cannot be generally determined depending on the layer configuration, the type of b, the application, the shape of the molded product, the required physical properties, etc., but is usually suitably selected from the ranges of 5 to 2000 μm, more preferably 10 to 500 μm, and particularly 10 to 200 μm for layer a, 5 to 5000 μm, more preferably 30 to 1000 μm for layer b, and 5 to 400 μm, more preferably 10 to 150 μm for the adhesive resin layer. Furthermore, the thickness ratio of layer a to the adhesive resin layer is usually such that layer a is thicker, and the ratio (thickness ratio) of layer a / adhesive resin layer is usually 1 to 100, preferably 1 to 50, and particularly preferably 1 to 10.

[0108] Furthermore, in the above multilayer structure, the thickness ratio of layer a to layer b is typically greater than that of layer b when the thicknesses of all layers of the same type in the multilayer structure are added together, with the ratio (thickness ratio) of layer b to layer a typically being 1 to 100, preferably 3 to 20, and particularly preferably 6 to 15. If layer a is too thin, mechanical properties such as rigidity and impact resistance tend to be insufficient, and thickness control tends to be unstable. Conversely, if layer a is too thick, bending fatigue resistance tends to be poor and the structure tends to be uneconomical. Furthermore, if layer b is too thin, rigidity tends to be insufficient, and conversely, if layer b is too thick, bending fatigue resistance tends to be poor and the structure tends to be large in mass. On the other hand, if the adhesive resin layer is too thin, interlayer adhesion tends to be insufficient and thickness control tends to be unstable. Conversely, if layer b is too thick, the structure tends to be large in mass and uneconomical. Furthermore, in order to improve moldability and various physical properties, the various additives described above, and various modifiers, fillers, other resins, and the like other than the EVOH (B) used in the resin composition may also be added to each layer of the multilayer structure within a range that does not impair the effects of the present invention.

[0109] Furthermore, it is also preferable to perform a stretching treatment to improve the physical properties of the multilayer structure. The stretching treatment may be either uniaxial or biaxial stretching. Stretching at as high a ratio as possible results in better physical properties, and molded products such as stretched films, stretched sheets, stretched containers, and stretched bottles can be obtained that are free of pinholes, cracks, stretching unevenness, delamination, and other defects during stretching. As stretching methods, roll stretching, tenter stretching, tubular stretching, stretch-blow methods, and deep drawing and vacuum-pressure forming, which have high stretching ratios, can also be used. In the case of biaxial stretching, either simultaneous biaxial stretching or sequential biaxial stretching can be used. The stretching temperature is usually selected from the range of 40 to 170°C, preferably approximately 60 to 160°C. If the stretching temperature is below 60°C, poor stretchability results, while if it exceeds 170°C, it tends to be difficult to maintain a stable stretched state.

[0110] After the stretching is completed, it is also preferable to heat set the stretched film for the purpose of imparting dimensional stability. Heat setting can be carried out by known means, and the stretched film is heat-treated, for example, at typically 80 to 180°C, preferably 100 to 165°C, for typically 2 to 600 seconds while maintained in a tensioned state. When used for heat-shrink packaging of raw meat, processed meat, cheese, etc., the film is not heat-set after stretching, but is used as a product film. After the raw meat, processed meat, cheese, etc. are placed in the film, the film is heat-treated at typically 50 to 130°C, preferably 70 to 120°C, for typically 2 to 300 seconds to heat-shrink the film and allow for close packaging.

[0111] The multilayer structure can be used as it is in various shapes, such as films, sheets, tapes, bottles, pipes, filaments, and modified cross-section extrudates. Furthermore, when a cup- or tray-shaped multilayer container is obtained from a multilayer sheet or film, a drawing method is used, specifically vacuum forming, pressure forming, vacuum pressure forming, and plug-assisted vacuum pressure forming. Furthermore, when a tube- or bottle-shaped multilayer container is obtained from a multilayer parison (a hollow tubular preform before blowing), a blow molding method is used, specifically extrusion blow molding (double-head, mold-moving, parison-shift, rotary, accumulator, horizontal parison, etc.), cold parison blow molding, injection blow molding, and biaxial stretch blow molding (extrusion cold parison biaxial stretch blow molding, injection cold parison biaxial stretch blow molding, injection in-line biaxial stretch blow molding, etc.). The resulting multilayer structure may be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making, deep drawing, box processing, tube processing, splitting processing, etc., as needed.

[0112] <Modifier for ABS resin and method for modifying ABS resin> The modifier for ABS resin of the present invention contains modified EVOH (B1). That is, the modified EVOH (B1) used in the resin composition itself is used as a modifier for ABS resin (A). This makes it possible to improve the oil resistance of ABS resin (A). Details of the ABS resin (A) and the modified EVOH (B1) have already been described, and therefore further description will be omitted.

[0113] The ABS resin (A) can be modified by adding the modified EVOH (B1) to the ABS resin (A).

[0114] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0115] <Materials> First, the details of the materials used in the examples and comparative examples are shown below. - (A) ABS resin (product name: TOYOLAC 600-309, manufactured by Toray Industries, Inc.) - (B1-1) Modified EVOH in which aliphatic polyester units derived from ring-opening polymerization of ε-caprolactone are bonded to the side chain (modified EVOH having a structural unit represented by chemical formula (1)): ethylene content 44 mol%, saponification degree 99.7%, modification rate 7.2 mol%, average chain length of graft chains (aliphatic polyester units) 1.4, glass transition temperature 23°C, MFR 12 g / 10 min (210°C, 2.16 kg) (B1-2) Modified EVOH having aliphatic polyester units derived from the ring-opening polymerization of ε-caprolactone bonded to side chains (modified EVOH having a structural unit represented by chemical formula (1)): ethylene content 32 mol%, degree of saponification 99.7%, modification rate 7.0 mol%, average chain length of graft chains (aliphatic polyester units) 1.4, glass transition temperature 30°C, MFR 12 g / 10 min (210°C, 2.16 kg) (B) Unmodified EVOH: ethylene content 32 mol%, degree of saponification 99.7%, glass transition temperature 61°C, MFR 12 g / 10 min (210°C, 2.16 kg)

[0116] Example 1 Material (A) and material (B1-1) were charged into a twin-screw kneading extruder (TEX30α, manufactured by Nippon Steel Corporation), and each resin was transported and melt-kneaded to obtain a resin composition consisting of 99% material (A) and 1% material (B1).

[0117] Examples 2 to 6 and Comparative Examples 1 and 2 Resin compositions were prepared in the same manner as in Example 1, except that the types and amounts of the components were changed as shown in Table 1.

[0118] Measurements and evaluations were carried out for the following evaluation items (mass change rate, strength change, contact angle) for Examples 1 to 6 and Comparative Examples 1 and 2. These results are shown in Table 1 below.

[0119] [Mass Change Rate] The resin compositions prepared in each Example and Comparative Example were cut into test specimens measuring 80 mm in length, 10 mm in width, and 4 mm in thickness using an injection molding machine. The test specimens were immersed in a test oil (Daphne Super Gear Oil 150, manufactured by Idemitsu Kosan Co., Ltd.) at 23°C for 168 hours (immersion test conditions conforming to JIS K7114).

[0120] The mass (W1) before the immersion test and the mass (W2) after the immersion test with the oil removed were measured using a precision balance, and the mass change rate of the test piece before and after the immersion test was calculated using the following formula: Mass change rate (%) = (W2 - W1) ÷ W1 × 100

[0121] [Strength Change] A tensile test was performed on each of the test pieces before and after the immersion test using a tensile tester (Shimadzu Corporation's bench-top precision universal testing machine AGS-X), and the strength change was calculated from the tensile strength before the immersion test (TS1) and the tensile strength after the immersion test (TS2) (tensile measurement conditions conforming to JIS K6251). The strength change was calculated using the following formula: Strength change (%) = (TS2 - TS1) ÷ TS1 × 100

[0122] [Contact Angle] The resin compositions prepared in each Example and Comparative Example were cut into test pieces measuring 200 mm in length, 20 mm in width, and 4 mm in thickness using an injection molding machine. These test pieces were conditioned for 3 days at 23°C and 50% RH. Thereafter, using a surface / interfacial tension measuring device (manufactured by Kyowa Interface Science Co., Ltd.), 2 μm of water was dropped onto the test pieces conditioned at 23°C and 50% RH, and the data after 120 seconds was recorded as the contact angle.

[0123]

[0124] The above results show that Examples 1 to 6 have smaller mass change rates and better oil resistance than Comparative Example 1, which does not contain modified EVOH (B1). Furthermore, comparing Examples 1 to 4 and 6 with Example 5, it is clear that by having a content of modified EVOH (B1) of 40 mass% or less, not only is oil resistance improved but strength change is also improved, resulting in a more excellent modification effect. Furthermore, Comparative Example 2 shows that the effect of the present invention cannot be obtained with unmodified EVOH (B) and is an effect specific to modified EVOH (B1).

[0125] 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 all intended to fall within the scope of the present invention.

[0126] Molded articles obtained from the resin composition of the present invention have excellent oil resistance and can therefore be widely used.

Claims

1. A resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol resin (B), wherein the ethylene-vinyl alcohol resin (B) contains a modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1). 【Chemical 1】

2. A resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol resin (B), wherein the mass change rate in the following immersion test is 0.45% or less. [Immersion Test] Measure the mass (W 1 ) of a test piece of the resin composition with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. Next, after immersing the test piece in a test oil (Daphne Super Gear Oil 150, manufactured by Idemitsu Kosan Co., Ltd.) at 23°C for 168 hours, wipe off the test oil and measure the mass (W 2 ) of the test piece, and calculate the mass change rate (%) from the following formula. Mass change rate (%) = (W 2 - W 1 ) / W 1 × 100

3. The resin composition according to claim 1 or 2, wherein the content of the ethylene-vinyl alcohol resin (B) is 1 to 70 parts by mass with respect to a total of 100 parts by mass of the ABS resin (A) and the ethylene-vinyl alcohol resin (B).

4. The resin composition according to claim 1 or 2, wherein the content of the ethylene-vinyl alcohol resin (B) is 1 to 40 parts by mass with respect to a total of 100 parts by mass of the ABS resin (A) and the ethylene-vinyl alcohol resin (B).

5. The resin composition according to claim 1, wherein the modification rate of the modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1) is 0.1 to 30 mol%.

6. The resin composition according to claim 1 or 5, wherein the modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1) is a ring-opening polymer of a lactone ring having 3 to 10 carbon atoms constituting the ring.

7. A molded article comprising the resin composition according to claim 1 or 2.

8. The molded article according to claim 7, wherein the molded article is a sheet or a film.

9. A modifier for ABS resin comprising a modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1). 【Chemical 2】

10. A method for producing a resin composition, comprising a step of incorporating a modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1) into an ABS resin (A). [Chemical Formula 3]

11. A method for modifying an ABS resin, comprising a step of incorporating a modified ethylene-vinyl alcohol resin (B1) having a structural unit represented by the following chemical formula (1) into an ABS resin (A). 【Chemical Formula 4】

12. A molded article formed from a resin composition containing an ABS resin (A) and an ethylene-vinyl alcohol resin (B), wherein the contact angle of the molded article is less than 85°.

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