JP2023154456A - Resin composition and method for producing the same, and multilayer structure and recovery aid each used in the production method - Google Patents

Abstract

To provide a resin composition that suppresses fisheye defects in the film while exhibiting superior transparency and a method for producing the same, and a multilayer structure and a recovery aid each of which is used in the production method.SOLUTION: A resin composition includes PO (A), an EVA composition including two or more types of EVA different in ethylene unit content (B), EVOH with an ethylene unit content of 20-55 mol% and a degree of saponification of 95 mol% or more (C), and a fatty acid bivalent metal salt (D), wherein the EVA composition (B) has a degree of saponification of 5 mol% or less and an acid modification level of 0.01 mmol/g or less.SELECTED DRAWING: None

Description

The present invention relates to a resin composition containing a polyolefin and a saponified ethylene-vinyl acetate copolymer, and a method for producing the same. The present invention also relates to a multilayer structure and a recovery aid used in the manufacturing method.

Conventionally, a polyolefin (hereinafter sometimes abbreviated as "PO") layer such as polyethylene or polypropylene, and a saponified ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVOH) layer, which has excellent barrier properties, have been used. Multilayered structures containing this material are used in various applications such as food packaging containers and fuel containers, taking advantage of their barrier properties. Such multilayer structures are used as various molded products such as films, sheets, cups, trays, and bottles. In recent years, activities to reduce waste plastic waste have become active, and waste containers made of the above-mentioned molded products from general households are collected and melt-molded to produce films, sheets, cups, trays, etc. It may be reused as recycled molded objects such as bottles. Such recycling technology is industrially useful from the viewpoint of waste reduction and economic efficiency, and has been put into practical use.

However, since PO and EVOH have poor compatibility, when a laminate having a PO layer and an EVOH layer is melt-molded again and reused as a recycled molded product, gelation may occur due to thermal deterioration during melt-molding. Degraded substances adhere to the screws in the extruder, etc., causing poor appearance such as fish eyes in the resulting molded products. In addition, streaks (striped patterns) may occur on the surface due to poor compatibility between PO and EVOH.

As a measure to solve such problems, Patent Document 1 describes a resin composition containing PO, EVOH, and an acid-modified olefin-carboxylic acid vinyl ester copolymer, and according to this resin composition, It is said that the occurrence of fish eyes, lines, and streaks in the resulting molded product can be reduced.

Patent Document 2 describes a resin composition for modifying recovered materials containing an ethylene-vinyl acetate copolymer and a saponified ethylene-vinyl acetate copolymer having an ethylene unit content of 70 mol% or more. , the recycled molded product obtained by using the recovered and modified resin composition when recovering and melt-molding a multilayer structure including a PO layer and an EVOH layer has suppressed discoloration and suppressed the occurrence of eye stain. It is said that the molded product has an excellent appearance.

Patent Document 3 describes one type selected from olefin-carboxylic acid vinyl ester copolymer and/or saponified product thereof, fatty acid metal salt and/or metal oxide, metal hydroxide, metal carbonate, and metal silicate. A resin composition containing the above metal compound is described, and a recycled molded product obtained using the resin composition when recovering and melt-molding a multilayer structure including a PO layer and an EVOH layer is In addition to excellent long-run moldability, there is no phase separation of thermoplastic resin and EVOH foreign matter (eye stain) mixed into the molded product, and there is excellent delamination resistance between the regrind layer and the adjacent layer, and the regrind layer has excellent resistance to delamination. It is said that the result is a molded product with no deterioration in mechanical properties such as impact resistance.

International Publication No. 2012/060371 International Publication No. 2009/041440 Japanese Patent Application Publication No. 2002-234971

However, as the quality of recycled molded products of multilayer structures including PO layers and EVOH layers has been improved in recent years, the transparency of recycled molded products has sometimes been insufficient using the above-mentioned conventional techniques. In order to improve such transparency, it is possible to increase the compatibility between PO and EVOH by adding a large amount of an acid-modified compatibilizer or increasing the degree of acid modification of the compatibilizer. However, recycled molded products whose transparency has been improved using such methods may be prone to fish eyes due to the increased viscosity of the resulting resin composition, and it is difficult to achieve both suppression of fish eyes and transparency. It was difficult.

The present invention has been made to solve the above problems, and provides a resin composition that suppresses fish eyes in a film and has excellent transparency, a method for producing the same, a multilayer structure used in the method, and a recovery aid. The purpose is to provide a drug.

The above issues are
[1] Polyolefin (A) (hereinafter sometimes abbreviated as "PO(A)"), ethylene-vinyl acetate copolymer composition (B) containing two or more types of EVA with different ethylene unit contents (hereinafter (sometimes abbreviated as "EVA composition (B)"), a saponified ethylene-vinyl acetate copolymer (C) having an ethylene unit content of 20 to 55 mol% and a saponification degree of 95 mol% or more ( (hereinafter sometimes abbreviated as "EVOH (C)") and fatty acid divalent metal salt (D), the degree of saponification of the EVA composition (B) is 5 mol% or less, and the amount of acid modification is 0.01 mmol. /g or less;
[2] The resin composition of [1], wherein the ethylene unit content of the EVA composition (B) is 50 to 90 mol%;
[3] In two or more types of EVA having different ethylene unit contents constituting the EVA composition (B), the difference in the ethylene unit content of at least one set of EVA is 5 to 50 mol%, [1] or The resin composition of [2];
[4] The resin composition according to any one of [1] to [3], wherein the mass ratio (B/C) of the EVA composition (B) and EVOH (C) is 0.05 to 2;
[5] The resin composition according to any one of [1] to [4], wherein the mass ratio (B/D) of the EVA composition (B) and the fatty acid divalent metal salt (D) is 3 to 100;
[6] The resin composition according to any one of [1] to [5], wherein the mass ratio (C/D) of EVOH (C) and fatty acid divalent metal salt (D) is 10 to 1000;
[7] The difference in refractive index (AB) between PO (A) and EVA composition (B) satisfies 0.015 to 0.050, and the refraction of EVOH (C) and EVA composition (B) The resin composition according to any one of [1] to [6], wherein the ratio difference (CB) satisfies 0.001 to 0.080;
[8] The content of PO (A) is 80 to 99% by mass, the content of EVA composition (B) is 0.10 to 6.0% by mass, and the content of EVOH (C) is 0. The resin composition according to any one of [1] to [7], wherein the content of fatty acid divalent metal salt (D) is 0.005 to 0.50% by mass;
[9] A step of melt-kneading a multilayer structure having a layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component, at least one of the layers constituting the multilayer structure. A manufacturing method for manufacturing the resin composition according to any one of [1] to [8], wherein the resin composition comprises at least one selected from the group consisting of an EVA composition (B) and a fatty acid divalent metal salt (D);
[10] A layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component, at least one of the layers constituting the multilayer structure contains EVA composition (B) and fatty acid diamide. A multilayer structure used in the manufacturing method of [9], comprising at least one member selected from the group consisting of valent metal salts (D);
[11] A step of mixing and melt-kneading a multilayer structure having a layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component and a recovery aid, wherein the recovery aid is EVA. A manufacturing method for manufacturing the resin composition according to any one of [1] to [8], comprising the composition (B) and the fatty acid divalent metal salt (D);
[12] A recovery aid used in the production method of [11], comprising the EVA composition (B) and the fatty acid divalent metal salt (D);
This is solved by providing

According to the present invention, a resin composition containing PO and EVOH that suppresses fish eyes in a film obtained using the resin composition and also has excellent transparency, a method for producing the same, and a method for producing the same. It is possible to provide a multilayer structure and a recovery aid used for this purpose.

A film obtained using the resin composition of the present invention is sometimes referred to as a "recovered film." The recovered film may be a single layer or a multilayer film, and in the Examples, transparency and fish-eye evaluations were mainly performed using a single layer film, but similar effects can be obtained with a multilayer film. In the present specification, "scrap" refers to collected ends and defective products generated when obtaining a multilayer structure or a molded product. As used herein, the term "main component" means more than 50% by mass, preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably consists essentially only of that component. do.

The resin composition of the present invention contains PO (A), an EVA composition (B), EVOH (C), and a fatty acid divalent metal salt (D), and the degree of saponification of the EVA composition (B) is 5 mol%. The following is a resin composition having an acid modification amount of 0.01 mmol/g or less. By including the EVA composition (B) containing two or more types of EVA with different ethylene unit contents, the transparency of the single-layer film obtained by melt-molding the resin composition containing PO (A) and EVOH (C) can be improved. The characteristics tend to be superior. That is, recycled molded products (such as recovered films) obtained by recovering and melt-molding materials containing PO (A) and EVOH (C) tend to have excellent transparency. Furthermore, by including the fatty acid divalent metal salt (D), the number of fish eyes in the recovered film tends to decrease. Furthermore, surprisingly, by including the EVA composition (B) and the fatty acid divalent metal salt (D), the transparency of the recovered film tends to be even better.

(PO(A))
The resin composition of the present invention contains PO(A). PO (A) used in the present invention is, for example, a polyethylene resin such as high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene; ethylene, 1-butene, 1-hexene, 4-methyl - Ethylene copolymer copolymerized with α-olefins such as 1-pentene or acrylic ester; polypropylene; α-olefins such as propylene and ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, etc. Poly(1-butene); poly(4-methyl-1-pentene); ionomer resin, etc. Among these, PO(A) is preferably a polyethylene resin such as polyethylene or an ethylene copolymer, or a polypropylene resin such as polypropylene or a polypropylene copolymer, and more preferably a polyethylene resin. One type may be used alone, or two or more types may be used in combination.

The refractive index of PO(A) measured by a known prism coupling method is preferably 1.500 or more, more preferably 1.505 or more. Moreover, the refractive index of PO(A) is preferably 1.540 or less, more preferably 1.530 or less. When the refractive index of PO (A) is within the above range, it is easy to adjust the relationship of the refractive index with EVA composition (B) and EVOH (C), etc., which will be described later, and the transparency of the resulting resin composition is increased. There is a tendency to The refractive index of PO(A) can be measured, for example, by the method described in Examples.

(EVA composition (B))
The resin composition of the present invention includes an EVA composition (B) containing two or more types of EVA having different ethylene unit contents. If only one type of ethylene-vinyl acetate copolymer is used, the compatibility between the polyolefin (A) and EVOH (C) tends to decrease, and the transparency of the recovered film tends to deteriorate. The EVA composition (B) may consist of two types or three or more types of EVA. Hereinafter, a preferred embodiment of the EVA composition (B) means an embodiment after mixing two or more types of EVA, for example, 50 parts by mass of EVA with an ethylene unit content of 90 mol%, 75 parts by mass of EVA with an ethylene unit content of 75 The ethylene unit content of the EVA composition (B), which is a blend of 50% by mass of EVA (mol%), is 83% by mole.

It is preferable that two or three types of EVA constitute the EVA composition (B). At least two types of EVA constituting the EVA composition (B) are EVA (b1) and EVA (b2) in descending order of ethylene unit content (if three types are included, the EVA with the lowest ethylene unit content is EVA) (b3)), the mass ratio (b1/B2) of EVA (b1) and EVA (b2) is preferably 30/70 or more and 90/10 or less. Moreover, the mass ratio (b1/(b2+b3)) of EVA (b1) to the total amount of EVA (b2) and EVA (b3) is preferably 30/70 or more and 90/10 or less. The proportion of EVA (b1) in the EVA composition (B) is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 45% by mass or more. Further, the proportion of EVA (b1) in the EVA composition (B) may be 95% by mass or less, 85% by mass or less, or 75% by mass or less.

The EVA composition (B) may be saponified, and the degree of saponification is 5 mol% or less. If the degree of saponification of the EVA composition (B) exceeds 5 mol%, the compatibility between PO (A) and EVOH (C) may decrease, and the transparency of the recovered film may deteriorate. The degree of saponification of the EVA composition (B) is more preferably 3 mol% or less, even more preferably 1 mol% or less, and particularly preferably not saponified. The degree of saponification of EVA composition (B) can be measured by NMR. The preferable aspect of the degree of saponification of EVA constituting EVA composition (B) is also the same as that of EVA composition (B).

The EVA composition (B) may be acid-modified, and the acid-modified amount is 0.01 mmol/g or less. When the amount of acid modification exceeds 0.01 mmol/g, the film tends to thicken due to reaction with EVOH (C), and fish eyes in the recovered film may increase. Furthermore, if the amount of acid modification exceeds 0.01 mmol/g, the action of the fatty acid divalent metal salt (D) is likely to be inhibited, and fish eyes in the recovered film may increase. The amount of acid modification of the EVA composition (B) is more preferably 0.007 mol/g or less, and even more preferably 0.005 mol/g or less. The amount of acid modification of the EVA composition (B) can be measured according to the method described in JIS K2501:2003. A preferred aspect of the degree of acid modification of EVA constituting EVA composition (B) is also the same as that of EVA composition (B).

The EVA composition (B) preferably has an ethylene unit content of 50 to 90 mol%. When the ethylene unit content is within the above range, the compatibility between PO (A) and EVOH (C) will improve, and the transparency of the recovered film will improve. The ethylene unit content of the EVA composition (B) is more preferably 60 mol% or more, and even more preferably 70 mol% or more. The ethylene unit content of the EVA composition (B) is more preferably 87 mol% or less, and even more preferably 85 mol% or less. From the viewpoint of improving the transparency of the recovered film, the ethylene unit content of EVA constituting the EVA composition (B) is preferably 20 to 95 mol%. The ethylene unit content of EVA composition (B) and EVA constituting EVA composition (B) can be measured by NMR.

When the EVA composition (B) contains EVA (b1) and EVA (b2), the ethylene unit content of EVA (b1) is preferably 65 mol% or more, more preferably 75 mol% or more, and 80 mol% or more. More preferably, it may be 85 mol% or more. Moreover, the ethylene unit content of EVA (b1) is preferably 99 mol% or less. Moreover, the ethylene unit content of EVA (b2) is preferably 30 mol% or more, and may be 50 mol% or more, 60 mol% or more, or 70 mol% or more. Moreover, the ethylene unit content of EVA (b2) is preferably 95 mol% or less, more preferably 90 mol% or less, and may be 85 mol% or less. When EVA (B) further contains EVA (b3), the ethylene unit content of EVA (b3) is preferably 25 mol% or more, more preferably 30 mol% or more, and even more preferably 35 mol% or more. Moreover, the ethylene unit content of EVA (b3) is preferably 90 mol% or less, and may be 70 mol% or less, or may be 50 mol% or less. When the ethylene unit content of EVA (b1), EVA (b2), and EVA (b3) is within the above range, transparency and suppression of fish eyes tend to be better.

The EVA constituting the EVA composition (B) may have a difference in ethylene unit content of at least one set of EVA of 5 to 50 mol% when taking the difference in ethylene unit content of each EVA. It is preferably 8 to 25 mol%, and even more preferably 10 to 20 mol%. For example, when the EVA composition (B) contains EVA (b1), EVA (b2), and EVA (b3), the difference in ethylene unit content of each EVA is determined by the ethylene unit content of EVA (b1) and EVA (b2). It means the difference in quantity, the difference in ethylene unit content between EVA (b1) and EVA (b3), and the difference in ethylene unit content between EVA (b2) and EVA (b3). More specifically, an EVA composition containing three types of EVA with an ethylene unit content of 50 mol%, 70 mol%, and 80 mol% (hereinafter, the ethylene unit content is expressed as Et50, Et70, and Et80, respectively). , the difference in ethylene unit content of each EVA can be calculated as follows.
Et70 - Et50 = 20 mol%
Et80 - Et50 = 30 mol%
Et80 - Et70 = 10 mol%

The melt flow rate (MFR) of the EVA composition (B) at 190° C. and under a load of 2160 g is not particularly limited, but is preferably 0.1 to 30 g/10 minutes. The MFR of the EVA composition (B) is more preferably 0.5 g/10 minutes or more, and even more preferably 1 g/10 minutes or more. Further, the MFR of the EVA composition (B) is more preferably 10 g/10 minutes or less, and even more preferably 5 g/10 minutes or less. A preferred aspect of the MFR of EVA constituting the EVA composition (B) is also the same as that of the EVA composition (B).

One or more of the EVA constituting the EVA composition (B) of the present invention may be modified with an unsaturated carboxylic acid or a derivative thereof, and examples of the unsaturated carboxylic acid or derivative thereof include, for example, acrylic Acids include methacrylic acid, maleic acid, fumaric acid, itaconic acid; methyl esters or ethyl esters of the above-mentioned acids; maleic anhydride, itaconic anhydride, and the like. These may be used alone or in combination of two or more.

EVA constituting the EVA composition (B) in the present invention may be crosslinked. Examples of the crosslinking modification method include a method of adding a crosslinking agent to the EVA composition (B), and the crosslinking agent is not particularly limited as long as it can crosslink each component. Preference is given to using organic peroxides. The organic peroxide used as a crosslinking agent is not particularly limited as long as it is an organic peroxide, and examples include dicumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di(t-butyl peroxide). ) hexane, 1,1-di(t-butylperoxy)cyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, 1,3-bis(t-butylperoxyisopropyl) Benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,3-bis(t-butylperoxy)diisopropylbenzene, n-butyl-4,4-bis(t-butyl Examples include peroxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, t-butyl cumyl peroxide, etc. . These may be used alone or in combination of two or more. Among them, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 1,1-di(t-butylperoxy)cyclohexane are preferably used from the viewpoint of reactivity.

Further, in addition to the crosslinking agent, a crosslinking aid such as triallylisocyanurate or divinylbenzene may be used as necessary. The ethylene-vinyl acetate copolymer composition (B) containing the above-mentioned crosslinking agent can be crosslinked by applying heat and kneading it. At this time, the kneading temperature is preferably from the melting point of the EVA composition (B) to about 300°C.

Methods for producing EVA constituting the EVA composition (B) of the present invention include known production methods such as high-pressure radical polymerization, solution polymerization, and emulsion polymerization. The EVA constituting the EVA composition (B) can be appropriately selected from commercially available products, and examples thereof include Ultrasen manufactured by Tosoh Corporation, Levaprene and Levamelt manufactured by Lanxess Corporation, and the like.

The method for producing the EVA composition (B) is not particularly limited, but from the viewpoint of uniformly dispersing each component, various materials constituting the EVA composition (B) may be blended and then melt-kneaded using a kneading device. is preferred. The kneading device is not particularly limited as long as each component can be uniformly dispersed, and the kneading device can be manufactured using a commonly used resin kneading device. Examples include kneading devices such as a single-screw extruder, a twin-screw extruder, a multi-screw extruder, a Banbury mixer, a pressure kneader, a rotating roll, and an internal mixer. Among these, a twin-screw extruder is more preferable because it has excellent dispersibility and continuous productivity. The screw rotation speed when performing kneading with a twin screw extruder is not particularly limited, but it is preferably kneaded at 50 rpm or more and 3000 rpm or less, more preferably 100 rpm or more and 2000 rpm or less, and even more preferably 150 rpm or more and 1000 rpm or less.

The proportion of EVA in the EVA composition (B) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 99% by mass or more, and the EVA composition (B) may be composed only of EVA. In addition, when the EVA composition (B) contains a crosslinking agent and a crosslinking aid as necessary, the proportion of EVA, the crosslinking agent, and the crosslinking aid as necessary in the EVA composition (B) is 80% by mass. The above is preferably 90% by mass or more, more preferably 95% by mass or more, particularly preferably 99% by mass or more, and the EVA composition (B) is composed only of EVA, a crosslinking agent, and, if necessary, a crosslinking aid. may have been

(EVOH(C))
The resin composition of the present invention contains EVOH (C) having an ethylene unit content of 20 to 55 mol% and a saponification degree of 95 mol% or more. When the ethylene unit content of EVOH (C) is 20 mol% or more, the compatibility with PO (A) improves. The ethylene unit content of EVOH (C) is more preferably 25 mol% or more. Further, when the ethylene unit content of EVOH (C) is 55 mol% or less, the gas barrier properties of the multilayer structure that can be used as a raw material for the resin composition of the present invention are improved. The ethylene unit content of EVOH (C) is more preferably 50 mol% or less.

The degree of saponification of the EVOH (C) is 95 mol% or more, more preferably 98 mol% or more, from the viewpoint of gas barrier properties and thermal stability of the multilayer structure that can be used as a raw material for the resin composition of the present invention. , more preferably 99 mol% or more. The degree of saponification of EVOH (C) may be 100 mol% or less.

The MFR of EVOH (C) at 210° C. and under a load of 2160 g is preferably 0.1 to 50 g/10 minutes from the viewpoint of melt moldability and extrusion moldability. The MFR of EVOH (C) is more preferably 0.5 g/10 minutes or more, and even more preferably 1 g/10 minutes or more. Further, the MFR of EVOH (C) is more preferably 20 g/10 minutes or less, and even more preferably 10 g/10 minutes or less.

EVOH (C) may have units derived from monomers other than ethylene, vinyl acetate, and saponified products thereof, as long as the object of the present invention is not impaired. When EVOH (C) has the other monomer units, the content of each of the other monomer units relative to the total structural units of EVOH (C) is preferably 30 mol% or less. , more preferably 20 mol% or less, even more preferably 10 mol% or less, particularly preferably 5 mol% or less. Moreover, when EVOH (C) has a unit derived from the above-mentioned other monomer, the lower limit may be 0.05 mol% or 0.10 mol%. Examples of the other monomers include alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4- Diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2- Methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6- Alkenes having ester groups such as acyloxy-1-hexene, 5,6-diasiloxy-1-hexene, 1,3-diacetoxy-2-methylenepropane, or saponified products thereof; acrylic acid, methacrylic acid, crotonic acid, itaconic acid, etc. unsaturated acids or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefins such as vinylsulfonic acid, allylsulfonic acid, and methalylsulfonic acid. Sulfonic acid or its salt; vinyl silane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, γ-methacryloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketone, N-vinylpyrrolidone, vinyl chloride , vinylidene chloride, etc.

EVOH (C) may be post-modified by methods such as urethanization, acetalization, cyanoethylation, and oxyalkylenation.

EVOH (C) can be used alone or in combination of two or more.

(Fatty acid divalent metal salt (D))
The resin composition used in the present invention contains a fatty acid divalent metal salt (D). By containing the fatty acid divalent metal salt (D), it is possible to suppress the occurrence of fish eyes resulting from aggregation of degraded substances. Examples of fatty acid divalent metal salts (D) include lauric acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, basic stearic acid, hydroxystearic acid, basic hydroxystearic acid, Examples include metal salts of higher fatty acids having 12 or more carbon atoms, such as nonadecanoic acid, oleic acid, behenic acid, montanic acid, and linoleic acid.

In addition, fatty acid metal salts having carbon atoms of 11 or less (acetate, propionate, etc.), metal salts other than fatty acid metal salts (nitrate, sulfate, etc.), etc. can also be used.

Further, the divalent metal salt constituting the fatty acid divalent metal salt (D) may be any metal salt of Group 2 of the periodic table and various divalent transition metal salts, such as magnesium salt, calcium salt, zinc salt, etc. salts, cobalt salts, manganese salts, and the like. Among these, from the viewpoint of productivity and practicality, at least one kind selected from the group consisting of magnesium salts, calcium salts, and zinc salts is preferable as the divalent metal salt constituting the fatty acid divalent metal salt (D).

The divalent metal ion constituting the fatty acid divalent metal salt (D) contained in the resin composition of the present invention may exist in a state dissociated from an anion. Further, it may exist in a coordinated state with a group (for example, a carboxy group, a hydroxyl group, etc.) possessed by EVOH (C) or other optional components.

(Adhesive resin (E))
In addition to the above-mentioned PO (A), EVA composition (B), EVOH (C) and fatty acid divalent metal salt (D), the adhesive resin (E) is used as a component constituting the resin composition of the present invention. It is preferable to contain. As the adhesive resin (E), for example, a modified olefin polymer containing a carboxyl group obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to an olefin polymer by an addition reaction, a graft reaction, etc. can be mentioned. Examples of unsaturated carboxylic acids or anhydrides thereof include maleic acid, maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride, etc. Among them, maleic anhydride is preferably used. Specifically, maleic anhydride graft modified polyethylene, maleic anhydride graft modified polypropylene, maleic anhydride graft modified ethylene-propylene copolymer, maleic anhydride graft modified ethylene-ethyl acrylate copolymer, maleic anhydride graft modified ethylene -Vinyl acetate copolymers, etc., or a mixture of two or more thereof is preferred.

(Resin composition)
The content of PO(A) in the resin composition of the present invention is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 87% by mass or more from the viewpoint of the transparency of the recovered film and fish eyes. . Moreover, the content of PO(A) is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 96% by mass or less. When the content of PO(A) is 99% by mass or less, costs tend to be suppressed when the resin composition of the present invention is produced by recovering a multilayer structure including an EVOH layer.

From the viewpoint of transparency of the recovered film, the content of the EVA composition (B) in the resin composition of the present invention is preferably 0.10% by mass or more, more preferably 0.25% by mass or more, and 0.5% by mass or more. More preferably, the amount is % by mass or more. Further, the content of the EVA composition (B) in the resin composition of the present invention is preferably 6.0% by mass or less, more preferably 3.0% by mass or less, and 2.0% by mass or less from the viewpoint of suppressing fish eyes. It is more preferably less than % by mass.

The content of EVOH (C) in the resin composition of the present invention is preferably 0.10% by mass or more, more preferably 0.5% by mass or more, and even more preferably 2.0% by mass or more. When the content of EVOH (C) is 0.10% by mass or more, costs tend to be suppressed when the resin composition of the present invention is produced by recovering a multilayer structure including an EVOH layer. Further, the content of EVOH (C) in the resin composition of the present invention is preferably 20% by mass or less, more preferably 15% by mass or less, and 10% by mass or less from the viewpoint of the transparency of the recovered film and fish eyes. It is more preferable, and particularly preferably 6.0% by mass or less.

The content of the fatty acid divalent metal salt (D) in the resin composition of the present invention is preferably 0.005% by mass or more, more preferably 0.015% by mass or more, and even more preferably 0.020% by mass or more. Further, the content of the fatty acid divalent metal salt (D) is preferably 1.2% by mass or less, more preferably 0.50% by mass or less, even more preferably 0.30% by mass or less, and 0.25% by mass or less. It is even more preferable, and particularly preferably 0.15% by mass or less. When the content of the fatty acid divalent metal salt (D) is within the above range, fish eyes in the recovered film tend to be suppressed.

The mass ratio (B/C) of the EVA composition (B) and EVOH (C) in the resin composition of the present invention is preferably 0.05 to 2. When the mass ratio (B/C) is 0.05 or more, the transparency of the recovered film tends to improve. The mass ratio (B/C) is more preferably 0.1 or more, and even more preferably 0.2 or more. Moreover, when the mass ratio (B/C) is 2 or less, fish eyes in the obtained recovered film tend to be suppressed. The mass ratio (B/C) is more preferably 1.5 or less, and even more preferably 1.0 or less.

The mass ratio (B/D) of the EVA composition (B) and the fatty acid divalent metal salt (D) in the resin composition of the present invention is preferably 3 to 100. When the mass ratio (B/D) is 3 or more, transparency tends to improve. The mass ratio (B/D) is more preferably 5 or more, and even more preferably 10 or more. Moreover, when the mass ratio (B/D) is 100 or less, fish eyes in the recovered film tend to be suppressed. The mass ratio (B/D) is more preferably 75 or less, and even more preferably 50 or less.

The mass ratio (C/D) of EVOH (C) to fatty acid divalent metal salt (D) in the resin composition of the present invention is preferably 10 to 1000. When the mass ratio (C/D) is 10 or more, thermal deterioration during melt-kneading of EVOH (C) is suppressed, and fish eyes in the recovered film tend to be suppressed. The mass ratio (C/D) is more preferably 20 or more, and even more preferably 50 or more. Furthermore, when the mass ratio (C/D) is 1000 or less, fish eyes tend to be suppressed. C/D is more preferably 500 or less, and even more preferably 200 or less.

The difference in refractive index (A-B) between PO (A) and EVA composition (B) in the resin composition of the present invention satisfies 0.015 to 0.050, and It is preferable that the difference in refractive index (CB) in B) satisfies 0.001 to 0.080. When the refractive index difference of each component is within the above range, the transparency of the recovered film is improved. Although the reason is not clear, the presence of the EVA composition (B) that satisfies the refractive index difference at the interface between the matrix of PO (A) and the domain of EVOH (C) results in the apparent refraction of EVOH (C). Since the refractive index approaches that of PO(A), light scattering in the recovered film is suppressed, and it is presumed that the transparency of the recovered film is improved as a result. The difference in refractive index (AB) between PO (A) and EVA composition (B) is more preferably 0.020 to 0.045, and even more preferably 0.025 to 0.040. Further, the difference in refractive index (CB) between EVOH (C) and EVA composition (B) is more preferably 0.010 to 0.070, and even more preferably 0.030 to 0.060.

(other compounds)
PO (A), EVA composition (B), EVOH (C), aliphatic divalent metal salt (D) and adhesive resin (E) are added to the resin composition of the present invention within a range that does not impede the effects of the present invention. It is also possible to contain other compounds. Examples of the other compounds include PO (A), EVA composition (B), EVOH (C), resins other than adhesive resin (E), carboxylic acid compounds, phosphoric acid compounds, boron compounds, metal salts ( Examples include alkali metal salts, alkaline earth metal salts other than fatty acid divalent metal salts (D)), antioxidants, ultraviolet absorbers, plasticizers, lubricants, fillers, and antistatic agents. The content of the other compound in the resin composition of the present invention is usually 5% by mass or less, preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. When the resin composition of the present invention contains a carboxylic acid compound, a phosphoric acid compound, a boric acid compound, or a metal salt, it is preferable that these compounds are mixed with EVOH (C) in advance.

Examples of resins other than PO (A), EVA composition (B), EVOH (C), and adhesive resin (E) include polyamide, polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, epoxy resin, and acrylic resin. , urethane resin, polyester resin, etc.

The carboxylic acid compound may be a monocarboxylic acid, a polycarboxylic acid, or a combination thereof. The carboxylic acid compound may be an ion, and such carboxylic acid ion may form a salt with a metal ion. The content of carboxylic acid and carboxylic acid ion is preferably 0.05 to 20 ppm. As the carboxylic acid compound, for example, aliphatic carboxylic acids such as acetic acid and stearic acid are preferably used. When the resin composition of the present invention contains a carboxylic acid compound, it tends to prevent coloring during melt molding.

The phosphoric acid compound is not particularly limited, and various acids such as phosphoric acid and phosphorous acid, salts thereof, etc. can be used. The phosphate may be contained in any form of primary phosphate, secondary phosphate, or tertiary phosphate, but primary phosphate is preferred. The cation type is not particularly limited either, but alkali metal salts are preferred. Among these, sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferred. When the resin composition of the present invention contains a phosphoric acid compound, the content of the phosphoric acid compound is preferably 0.05 to 25 ppm in terms of phosphate radicals. When the content of the phosphoric acid compound is 0.05 ppm or more, the coloring resistance during melt molding tends to be good. On the other hand, when the content of the phosphoric acid compound is 25 ppm or less, melt moldability tends to be good.

The boron compound is not particularly limited, and examples include boric acids, boric acid esters, borates, and boron hydrides. Specifically, boric acids include orthoboric acid, metaboric acid, tetraboric acid, etc., boric acid esters include triethyl borate, trimethyl borate, etc., and borates include the various borates mentioned above. Examples include alkali metal salts of acids, alkaline earth metal salts, borax, and the like. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferred. When the resin composition of the present invention contains a boron compound, the content of the boron compound is preferably 1 to 100 ppm in terms of boron element. When the content of the boron compound is 1 ppm or more, torque fluctuations during heating and melting tend to be suppressed. On the other hand, when the boron compound content is 100 ppm or less, moldability tends to be maintained well.

The cation type of the alkali metal salt is not particularly limited, but sodium salt or potassium salt is preferred. The type of anion of the alkali metal salt is also not particularly limited. It can be added as a carboxylate, carbonate, hydrogen carbonate, phosphate, hydrogen phosphate, borate, hydroxide, etc. When the resin composition of the present invention contains an alkali metal salt, the content of the alkali metal salt is preferably 0.5 to 25 ppm in terms of metal element. When the content of the alkali metal salt is 0.5 ppm or more, interlayer adhesion tends to be good. On the other hand, when the content of the alkali metal salt is 25 ppm or less, the melt stability tends to be excellent.

The cation type of the alkaline earth metal salt other than the fatty acid divalent metal salt (D) is not particularly limited, but magnesium salts or calcium salts are preferred. The type of anion of the alkaline earth metal salt is also not particularly limited. It can be added as carbonate, hydrogen carbonate, phosphate, hydrogen phosphate, borate, hydroxide, etc. The content of alkaline earth metal salt is preferably 0.5 to 25 ppm. When the resin composition of the present invention contains an alkaline earth metal salt, it tends to suppress deterioration when a molded article is repeatedly melt-molded and suppress the generation of deteriorated products such as gel.

Antioxidants: 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis(6-t-butylphenol), 2,2'-methylenebis( 4-methyl-6-t-butylphenol), octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis(6-t-butylphenol), etc. .

Ultraviolet absorber: ethylene-2-cyano-3,3'-diphenylacrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl- 5'-methylphenyl) 5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, etc.

Plasticizers: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate esters, etc.

Lubricants: Stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisstearic acid amide, methylol stearic acid amide, N-oleyl palmitamide, N-stearyl erucamide, liquid paraffin, natural paraffin, synthetic paraffin , polyolefin wax, stearyl alcohol, lauryl alcohol, stearic acid, lauric acid, myristic acid, behenic acid, montanic acid, stearyl stearate, stearyl laurate, calcium stearate, magnesium stearate, zinc stearate, lead stearate, etc.

Fillers: fiberglass, asbestos, ballastonite, calcium silicate, etc.

Antistatic agents: glycerin monofatty acid ester, fatty acid diethanolamide, alkyl diethanolamine, alkyl sulfonate, alkylbenzene sulfonate, alkyl trimethyl ammonium salt, alkyl benzyl dimethyl ammonium salt, alkyl betaine, alkylimidazolium betaine, etc.

Of all the resins in the resin composition of the present invention, the proportion of PO (A), EVA composition (B) and EVOH (C) is preferably 80% by mass or more, more preferably 90% by mass or more, and 95% by mass. The above is more preferable, and 98% by mass or more is particularly preferable, and it may be substantially only PO (A), EVA composition (B) and EVOH (C), or it may be composed of PO (A), EVA composition (B) ) and EVOH (C) alone. When the resin composition of the present invention contains adhesive resin (E), among all the resins in the resin composition of the present invention, PO (A), EVA composition (B), EVOH (C) and adhesive resin ( The proportion occupied by E) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, and substantially contains PO (A) and EVA composition (B). ), EVOH (C) and adhesive resin (E) only, or PO (A), EVA composition (B), EVOH (C) and adhesive resin (E) only. . Further, the proportion of PO (A), EVA composition (B), EVOH (C), and fatty acid divalent metal salt (D) in the resin composition of the present invention is preferably 80% by mass or more, and 90% by mass or more. is more preferable, more preferably 95% by mass or more, particularly preferably 98% by mass or more, and is made essentially only of PO (A), EVA composition (B), EVOH (C) and fatty acid divalent metal salt (D). may be configured. When the resin composition of the present invention contains adhesive resin (E), PO (A), EVA composition (B), EVOH (C), fatty acid divalent metal salt (D) in the resin composition of the present invention The proportion occupied by the adhesive resin (E) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, and substantially PO(A), It may be composed only of the EVA composition (B), EVOH (C), fatty acid divalent metal salt (D), and adhesive resin (E).

(Method for manufacturing resin composition)
The method for producing the resin composition of the present invention is not particularly limited, but for example, a method of dry blending and melt-kneading PO (A), EVA composition (B), EVOH (C), and fatty acid divalent metal salt (D). ; At least one selected from the group consisting of PO (A), EVA composition (B), EVOH (C) and fatty acid divalent metal salt (D) is dry blended in advance, and then other components are blended. Melt-kneading method: At least one member selected from the group consisting of PO (A), EVA composition (B), EVOH (C), and fatty acid divalent metal salt (D) is melt-kneaded in advance, and then other components are mixed. A method of blending and melt-kneading; a multilayer structure having a layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component, an EVA composition (B) and a fatty acid divalent metal salt ( D) A method of melt-kneading a recovery aid containing PO (A); a multilayer structure having a layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component; Examples include a method of melt-kneading a multilayer structure containing the EVA composition (B) and the fatty acid divalent metal salt (D) in one layer. Further, when the resin composition of the present invention contains the other compound, the other compound may be added to the multilayer structure, whether mixed in the dry blending process or included in the layers constituting the multilayer structure. Even if it is a layer constituting a structure, it may be added as a recovery aid during melt-kneading.

Among these, it includes a step of melt-kneading a multilayer structure having a layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component, and at least one of the layers constituting the multilayer structure A method including at least one selected from the group consisting of EVA composition (B) and fatty acid divalent metal salt (D) is preferred from the viewpoint of practicality and economy. Furthermore, from the viewpoint of maintaining the performance as a multilayer structure, the layer containing PO (A) as a main component contains at least one member selected from the group consisting of an EVA composition (B) and a fatty acid divalent metal salt (D). It is more preferable. The method of including at least one selected from the group consisting of the EVA composition (B) and the fatty acid divalent metal salt (D) in at least one of the layers constituting the multilayer structure is not particularly limited, but for example, The EVA composition (B) and the fatty acid divalent metal salt (D) may be contained in separate layers, or may be contained in the same layer. Alternatively, the resin serving as the raw material for the layers constituting the multilayer structure may be dry-blended with the recovery aid or its components described below to directly form a film, or the resin serving as the raw material for the layers constituting the multilayer structure may be dry blended with a recovery aid or its components described below. After producing pellets by dry blending with a recovery aid or its components to be described later and melt-kneading, the pellets may be used to form a film.

Further, in the production of the resin composition of the present invention, a step of mixing and melt-kneading a multilayer structure having a layer containing PO (A) as a main component and a layer containing EVOH (C) as a main component and a recovery aid. A method in which the recovery aid includes the EVA composition (B) and the fatty acid divalent metal salt (D) is also preferable from the viewpoints of practicality and economic efficiency. At this time, the multilayer structure is preferably used as scraps pulverized by a known method. As a recovery aid added to the crushed scrap, for example, the EVA composition (B) and the fatty acid divalent metal salt (D) may be blended separately, but the EVA composition (B) It is preferable to dry blend a composition containing the fatty acid divalent metal salt (D) and melt-knead the pellet-shaped recovery aid, and then melt-knead the mixture. Note that the scrap obtained from one molded product may be used, or a mixture of related scraps obtained from two or more molded products may be used.

The recovery aid of the present invention includes an EVA composition (B) and a fatty acid divalent metal salt (D). By including the EVA composition (B), the recoverability becomes good, and the recycled molded product obtained after recovery becomes good in transparency. Furthermore, by including the fatty acid divalent metal salt (D), it tends to be possible to suppress the occurrence of fish eyes in the recycled molded product obtained after recovery. A preferred embodiment of the EVA composition (B) and fatty acid divalent metal salt (D) contained in the present recovery aid is the EVA composition (B) and fatty acid divalent metal salt (D) contained in the resin composition described above. ). The content of the EVA composition (B) in the recovery aid of the present invention is preferably 20% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, and may be 99% by mass or more, It may be 100% by mass or less. Further, the content of the fatty acid divalent metal salt (D) in the recovery aid of the present invention is preferably 0.1 to 25% by mass, more preferably 0.5 to 10% by mass. The proportion occupied by the EVA composition (B) and the fatty acid divalent metal salt (D) in the recovery aid of the present invention is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, It may be 99% by mass or more. The recovery aid of the present invention may essentially consist of only the EVA composition (B) and the fatty acid divalent metal salt (D).

Furthermore, the recovery aid of the present invention may contain PO(A) from the viewpoint of feedability during production of the recovery aid. When the recovery aid of the present invention contains PO(A), the content of PO(A) in the recovery aid of the present invention is preferably 20% by mass to 90% by mass, more preferably 30% to 80% by mass. preferable. When the recovery aid of the present invention contains PO (A), the content of the EVA composition (B) in the recovery aid of the present invention is preferably 10% by mass to 80% by mass, and preferably 20% by mass to 70% by mass. is more preferable. When the recovery aid of the present invention contains PO (A), the content of fatty acid divalent metal salt (D) in the recovery aid of the present invention is preferably 0.1% by mass to 15% by mass, and 1% by mass. More preferably 10% by mass. When the recovery aid of the present invention contains PO (A), the proportion of PO (A), EVA composition (B), and fatty acid divalent metal salt (D) in the recovery aid of the present invention is 90% by mass. The content is preferably at least 95% by mass, more preferably at least 97% by mass, and may be at least 99% by mass. The recovery aid of the present invention may essentially consist of only PO (A), EVA composition (B), and fatty acid divalent metal salt (D). Note that the PO(A) contained in the recovery aid may be the same as or different from the PO(A) constituting the multilayer structure that can be used as a raw material for the resin composition of the present invention.

The recovery aid of the present invention may contain compounds other than PO (A), EVA composition (B), and fatty acid divalent metal salt (D) as long as they do not impede the effects of the present invention. good. Examples of the other compounds include other compounds that may be included in the resin composition described above, and the recovery aid may also contain EVOH (C). The content of other compounds in the recovery aid of the present invention is usually 50% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 7% by mass or less, and 3% by mass or less. is particularly preferred.

From the viewpoint of compatibility, when the recovery aid of the present invention contains PO(A), the PO(A) contained in the recovery aid is the same as the PO(A) contained in the multilayer structure to be recovered. Preferably, it is a type of PO. For example, when the PO (A) contained in the multilayer structure to be recovered is polypropylene, it is preferable that the PO (A) contained in the recovery aid is also polypropylene, and the PO (A) contained in the multilayer structure to be recovered is preferably polypropylene. When the PO(A) contained is polyethylene, it is preferable that the PO(A) contained in the recovery aid is also polyethylene.

When the recovery aid of the present invention contains a compound other than the EVA composition (B) and the fatty acid divalent metal salt (D), the EVA composition (B) and the fatty acid divalent metal salt (D) and the other compounds It is preferable to melt and knead them in advance to form a recovery aid containing all of them before adding them to the recovered material. Such a recovery aid is preferably blended into the recovered material in the form of pellets. The recovered material is preferably pulverized to an appropriate size, and it is preferable that a recovery aid in the form of pellets is mixed with the pulverized recovered material.

Although only unused resin may be used as a raw material for the resin composition of the present invention, it is preferable to use recovered multilayer structures as described above as at least a part of the raw material to reduce the amount of waste and Preferable from the viewpoint of cost reduction. The proportion of the recovered material in the raw material of the resin composition of the present invention is preferably 50% by mass or more. In addition, as long as the effects of the present invention are not impaired, packaging materials (multilayer structures) consumed in the market may be used as raw materials for recovered materials. In that case, the packaging materials are cut and cut as necessary. After separation and washing, a process of melt-kneading using an extruder is generally adopted.

The multilayer structure used as a raw material for the resin composition of the present invention is not particularly limited, and examples include multilayer structures having the following layer configurations. In the following examples, the PO (A) layer is referred to as "A", the EVOH (C) layer as "C", the adhesive resin (E) layer as "E", the resin composition layer of the present invention as "F", and the direct Use “/” to indicate that they are stacked.
3 layers A/E/C, A/C/A
5 layers A/E/C/E/A, A/E/C/E/F
6 layers A/E/C/E/F/A, F/A/E/C/E/A, A/F/E/C/E/F, F/A/E/C/E/F
7 layers A/F/E/C/E/F/A, A/F/E/C/E/A/F, F/A/E/C/E/A/F

It is preferable that the multilayer structure has a layer of the resin composition of the present invention from the viewpoint of reducing the amount of waste and reducing costs. Further, from the viewpoint of improving interlayer adhesion, it is preferable that the EVOH (C) layer and the adhesive resin (E) layer are in contact with each other.

The overall thickness of the multilayer structure can be appropriately set depending on the application. The total thickness is preferably 20 to 2000 μm. When the total thickness is 20 μm or more, a highly rigid multilayer structure can be obtained. More preferably, the total thickness is 50 μm or more. On the other hand, when the total thickness is 2000 μm or less, a flexible multilayer structure can be obtained. More preferably, the total thickness is 1000 μm or less.

The method for manufacturing the multilayer structure is not particularly limited. For example, molding methods practiced in the general PO field, such as extrusion molding, blow molding, injection molding, thermoforming, etc., can be mentioned. Among these, coextrusion molding and co-injection molding are preferred, and coextrusion molding is more preferred.

The multilayer structure of the present invention is excellent in terms of environment and cost by including a layer containing the resin composition of the present invention as a main component. Further, the multilayer structure of the present invention preferably further includes a PO (A) layer, an EVOH (C) layer, and an adhesive resin (E) layer. Regarding the preferred layer structure and manufacturing method for the multilayer structure of the present invention, those described as examples having the resin composition layer of the present invention in the multilayer structure used as the above-mentioned raw material can be mentioned. Furthermore, the multilayer structure of the present invention may have resin layers other than the PO (A) layer, the EVOH (C) layer, and the adhesive resin (E) layer as long as the effects of the present invention are not impaired. good. Examples of the other resin layers include an ethylene-vinyl acetate copolymer layer, a polyester layer such as polyethylene terephthalate, a polyester elastomer layer, a polyamide layer such as nylon-6 and nylon-66, a polystyrene layer, a polyvinyl chloride layer, and a polychloride layer. Examples include a vinylidene layer, an acrylic resin layer, a vinyl ester resin layer, a polyurethane layer, and a polycarbonate layer.

The resin composition of the present invention can be produced into a film using a well-known melt extrusion molding machine, compression molding machine, transfer molding machine, injection molding machine, blow molding machine, thermoforming machine, rotary molding machine, dip molding machine, etc. It can be formed into any molded product such as sheets, tubes, bottles, and cups. The extrusion temperature for molding depends on the type of PO (A) constituting the resin composition of the present invention, the MFR of PO (A) and EVOH (C), the composition ratio of PO (A) and EVOH (C), or the molding machine. Although the temperature is appropriately selected depending on the type of temperature, in most cases it is in the range of 130 to 350°C.

Molded articles obtained by molding the resin composition of the present invention can be used as food packaging containers, beverage containers, cosmetic containers, fuel containers, pharmaceutical containers, and the like.

Hereinafter, the present invention will be explained in more detail using Examples, but the present invention is not limited to these Examples in any way.

<Evaluation method>
(1) Quantification of acid denaturation amount Measure the acid value of EVA composition (B), EVA (b1), EVA (b2), or EVA (b3) used in Examples and Comparative Examples based on JIS K2501:2003. Then, the amount of acid modification (mmol/g) was calculated from the acid value. The results are shown in Table 1.

(2) Measurement of refractive index Using PO (A), EVA composition (B), and EVOH (C) used in Examples and Comparative Examples, the refractive index was measured by a known prism coupling method. Specifically, 10 g of each resin was poured into the circular opening of a 100 μm thick iron plate spacer placed on a Teflon (registered trademark) sheet using a tabletop heat press device (Shinto Metal Industry Co., Ltd.). This was sandwiched between another Teflon (registered trademark) sheet and hot pressed at 200° C. for 120 seconds to obtain a pressed film with a thickness of 100 μm. Using the obtained press film, the refractive index in the thickness direction of a laser beam with a wavelength of 532 nm was measured using "Prism Coupler Model 2010/M" manufactured by Metricon.

(3) Evaluation of Transparency A square sample of 10 cm x 10 cm was cut out from the recovered single-layer film (I) obtained in Examples and Comparative Examples, centered at the center. Subsequently, the haze of the cut sample was measured in accordance with JIS K7375 using a Boick integrating sphere type light transmittance/total light reflectance meter ("Model HR-100" manufactured by Murakami Color Research Institute).

(4) Evaluation of fish eyes When producing the recovered single-layer films (II) obtained in Examples and Comparative Examples, a defect detector (FE Counter manufactured by Frontier Systems Co., Ltd.) was used to measure 0.08 m in width x 1 m in length. The number of fish eyes in (0.08 m ² ) was counted.The evaluation criteria were as follows.
A: Number of fish eyes 500 or less B: Number of fish eyes 501 or more and 1500 or less C: Number of fish eyes 1501 or more

<Materials used>
・PO(A)
A1: "Novatec (trademark) LJ400" LDPE, manufactured by Japan Polyethylene Co., Ltd., EVA composition (B)
(EVA(b1))
b1-1: EVA produced by a known method, ethylene unit content 90 mol%, saponification degree 0 mol%, acid modification amount 0.005 mmol/g, density 0.95 g/cm ³
b1-2: EVA produced by a known method, ethylene unit content 93 mol%, degree of saponification 0 mol%, acid modification amount 0.005 mmol/g, density 0.94 g/cm ³
b1-3: EVA produced by a known method, ethylene unit content 87 mol%, degree of saponification 0 mol%, acid modification amount 0.004 mmol/g, density 0.95 g/cm ³
b1-4: EVA saponified product produced by a known method, ethylene unit content 89 mol%, degree of saponification 97.1 mol%, acid modification amount 0.012 mmol/g, density 0.97 g/cm ³
b1-5: EVA produced by a known method, ethylene unit content 96 mol%, degree of saponification 0 mol%, acid modification amount 0.004 mmol/g, density 0.93 g/cm ³
(EVA(b2))
b2-1: EVA produced by a known method, ethylene unit content 75 mol%, degree of saponification 0 mol%, acid modification amount 0.003 mmol/g, density 1.00 g/cm ³
b2-2: EVA manufactured by a known method, ethylene unit content 87 mol%, degree of saponification 0 mol%, acid modification amount 0.004 mmol/g, density 0.95 g/cm ³
b2-3: EVA produced by a known method, ethylene unit content 43 mol%, degree of saponification 0 mol%, acid modification amount 0.003 mmol/g, density 1.11 g/cm ³
b2-4: EVA produced by a known method, ethylene unit content 70 mol%, degree of saponification 0 mol%, acid modification amount 0.15 mmol/g, density 0.95 g/cm ³
b2-5: EVA produced by a known method, ethylene unit content 90 mol%, degree of saponification 0 mol%, acid modification amount 0.005 mmol/g, density 0.95 g/cm ³
(EVA(b3))
b3-1: EVA produced by a known method, ethylene unit content 81 mol%, saponification degree 0 mol%, acid modification amount 0.003 mmol/g, density 0.97 g/cm ³
b3-2: EVA produced by a known method, ethylene unit content 43 mol%, degree of saponification 0 mol%, acid modification amount 0.003 mmol/g, density 1.11 g/cm ³
・EVOH (C)
C1: "EVAL (trademark) F171B" EVOH, manufactured by Kuraray Co., Ltd., ethylene unit content 32 mol%, degree of saponification 99 mol% or more C2: "EVAL (trademark) L171B" EVOH, manufactured by Kuraray Co., Ltd., contains ethylene units Amount: 27 mol%, saponification degree: 99 mol% or more C3: "Eval (trademark) G156B" EVOH, manufactured by Kuraray Co., Ltd., ethylene unit content: 48 mol%, saponification degree: 99 mol% or more, fatty acid divalent metal salt ( D)
StMg: Magnesium stearate StCa: Calcium stearate StZn: Zinc stearate/adhesive resin (E)
E1: "Admer (trademark) NF518" maleic anhydride modified polyethylene, manufactured by Mitsui Chemicals, Inc., density 0.91 g/cm ³

<Example>
Example 1
(Preparation of EVA composition (B1))
50 parts by mass of EVA (b1-1) and 50 parts by mass of EVA (b2-1) were dry blended, and a twin-screw extruder (twin-screw segment extruder "2D30W2" manufactured by Toyo Seiki Seisakusho Co., Ltd.) (D (mm) = EVA composition (B1) pellets were obtained by melt-molding using a screw (No. 25, L/D = 30, screws: same-direction, fully intermeshing type).

(Preparation of multilayer structure)
Using a coextrusion multilayer cast film forming device, the PO layer is made of low density polyethylene (LDPE; "Novatec (trademark) LJ400" made by Japan Polyethylene Co., Ltd.), and the barrier layer is made of EVOH (C) ("Eval" made by Kuraray Co., Ltd.). (trademark) F171B"), and the adhesive layer is a ^multilayer structure (LDPE layer/maleic anhydride A multilayer structure (5-layer coextruded multilayer cast film) having a layer thickness and layer structure of acid-modified polyethylene layer / EVOH layer / maleic anhydride-modified polyethylene layer / LDPE layer = 40 μm / 5 μm / 10 μm / 5 μm / 40 μm was formed. The film forming conditions at this time are shown below.
Coextrusion conditions PO layer extrusion temperature: Supply section/compression section/measuring section/die = 180/220/220/220°C
Barrier layer extrusion temperature: supply section/compression section/measuring section/die = 180/220/220/220°C
Adhesive layer extrusion temperature: supply section/compression section/measuring section/die = 180/220/220/220°C
Extruder:
・PO layer 32φ extruder GT-32-A type (manufactured by Plastic Engineering Research Institute Co., Ltd.)
・Barrier layer 20φ extruder Lab machine ME type CO-EXT (manufactured by Toyo Seiki Seisakusho Co., Ltd.)
・Adhesive layer 25φ extruder P25-18-AC type (manufactured by Osaka Seiki Kogyo Co., Ltd.)
T-die: 300mm width, 3 types, 5 layers (manufactured by Plastic Engineering Research Institute Co., Ltd.)
Cooling roll temperature: 80℃
Pick-up speed: 3.0m/min

(Preparation of single layer film)
The film was formed in the same manner as the multilayer structure described above, except that all the resin used in each extruder was changed to low-density polyethylene (LDPE; "Novatec (trademark) LJ400" manufactured by Japan Polyethylene Co., Ltd.). A 100 μm LDPE single layer film was obtained.

(Crush)
The multilayer structure obtained above was pulverized using a pulverizer with a diameter of 8 mmΦ mesh to produce a recovered multilayer structure. In addition, the single-layer film obtained above was pulverized using a pulverizer with a diameter of 8 mmΦ mesh to produce a recovered single-layer film.

(Preparation of recovered resin composition pellets)
The respective recovered materials obtained above were dry blended so that the mass ratio of multilayer structure recovered material/monolayer film recovered material was 50/50. For 100 parts by mass of the obtained dry blend resin, the EVA composition (B1) was 1.25 parts by mass, and the fatty acid divalent metal salt (D) was 0.03 parts by mass of magnesium stearate (StMg). Further, the mixture was dry blended and melt-kneaded. The melt kneading was carried out using a twin-screw segment extruder "2D30W2" manufactured by Toyo Seiki Seisakusho Co., Ltd. (D (mm) = 25, L/D = 30, screws: same direction fully meshing type), and the resin temperature was 220 ° C. The mixture was melt-kneaded to obtain recovered resin composition pellets (I) (cylindrical pellets with a diameter of 2 mm and a length of 4 mm). Furthermore, the obtained recovered resin composition pellets (II) were melt-kneaded again in the above-mentioned melt-kneading operation, and by melt-kneading a total of 5 times, the recovered resin composition pellets (II) (diameter 2 mm) were melt-kneaded. , cylindrical pellets with a length of 4 mm) were obtained.

(Formation of recovered single-layer film)
50 parts by mass of the recovered resin composition pellets (I) obtained above and 50 parts by mass of low-density polyethylene (LDPE; "Novatec (trademark) LJ400" manufactured by Japan Polyethylene Co., Ltd.) were dry blended, and Toyo Seiki Seisakusho Co., Ltd. Using a 20 mm extruder "D2020" (D (mm) = 20, L/D = 20, compression ratio 3.5, screw: full flight) under the following conditions, a single layer film was formed under the following conditions. A layered film (I) was obtained. In addition, single-layer film formation was performed under the same conditions as above, except that recovered resin composition pellets (II) were used instead of recovered resin composition pellets (I), to obtain recovered single-layer films (II). . During the production of the recovered single-layer film (II), fish eyes were evaluated according to the method described in the evaluation method (4) above. The results are shown in Table 1.
(Extrusion conditions)
Extrusion temperature: Supply section/compression section/measuring section/die = 180/220/220/220℃
Screw rotation speed: 40rpm
Cooling roll temperature: 50℃
Film thickness: 25μm

The obtained recovered monolayer film (I) was evaluated for transparency according to the method described in the evaluation method (3) above. The results are shown in Table 1.

Examples 2 to 38, Comparative Examples 1 to 11
Content and type of PO (A), content and type of EVA composition (B), content and type of EVOH (C), content and type of fatty acid divalent metal salt (D), and adhesive resin A multilayer structure, a single layer film, a recovered resin composition pellet, and a recovered single layer film were prepared and evaluated in the same manner as in Example 1, except that the content of (E) was changed as shown in Table 1. . The results are shown in Tables 1, 2, 3 and 4. In addition, in Comparative Example 1 and Comparative Example 3, EVA composition (B) was not added during production of EVA composition (B) pellets and during production of recovered resin composition pellets. Furthermore, in Comparative Example 5, EVA (b1-1) was used as it was as an EVA composition (B8).

Example 39
(Preparation of recovery aid pellets)
97.5 parts by mass of the EVA composition (B12) obtained in Example 21 and 2.5 parts by mass of magnesium stearate (StMg) as the fatty acid divalent metal salt (D) were dry blended, and the mixture was dried in a twin-screw extruder ( Recovery aid pellets were obtained by melt molding using a twin-screw segment extruder "2D30W2" manufactured by Toyo Seiki Seisakusho Co., Ltd. (D (mm) = 25, L/D = 30, screws: fully meshing in the same direction)). Ta.

(Preparation of multilayer structure)
Using a coextrusion multilayer cast film forming device, the PO layer was dry blended with 100 parts by mass of low-density polyethylene (LDPE; "Novatec (trademark) LJ400" manufactured by Japan Polyethylene Co., Ltd.) and 3 parts by mass of the above recovery aid pellets. The barrier layer is made of EVOH (C) ("EVAL (trademark) F171B" manufactured by Kuraray Co., Ltd.), and the adhesive layer is made of maleic anhydride-modified polyethylene ("Admar (trademark)" manufactured by Mitsui Chemicals Co., Ltd.). )NF518'') has a layer thickness and layer structure of LDPE layer/maleic anhydride modified polyethylene layer/EVOH layer/maleic anhydride modified polyethylene layer/LDPE layer = 40 μm/5 μm/10 μm/5 μm/40 μm. A multilayer structure (5-layer coextruded multilayer cast film) was formed.The film forming conditions at this time are shown below.
Coextrusion conditions PO layer extrusion temperature: Supply section/compression section/measuring section/die = 180/220/220/220°C
Barrier layer extrusion temperature: supply section/compression section/measuring section/die = 180/220/220/220°C
Adhesive layer extrusion temperature: supply section/compression section/measuring section/die = 180/220/220/220°C
Extruder:
・PO layer 32φ extruder GT-32-A type (manufactured by Plastic Engineering Research Institute Co., Ltd.)
・Barrier layer 20φ extruder Lab machine ME type CO-EXT (manufactured by Toyo Seiki Seisakusho Co., Ltd.)
・Adhesive layer 25φ extruder P25-18-AC type (manufactured by Osaka Seiki Kogyo Co., Ltd.)
T-die: 300mm width, 3 types, 5 layers (manufactured by Plastic Engineering Research Institute Co., Ltd.)
Cooling roll temperature: 80℃
Pick-up speed: 3.0m/min

(Preparation of single layer film)
The film was formed in the same manner as the multilayer structure described above, except that all the resin used in each extruder was changed to low-density polyethylene (LDPE; "Novatec (trademark) LJ400" manufactured by Japan Polyethylene Co., Ltd.). A 100 μm LDPE single layer film was obtained.

(Crush)
The multilayer structure obtained above was pulverized using a pulverizer with a diameter of 8 mmΦ mesh to produce a recovered multilayer structure. In addition, the single-layer film obtained above was pulverized using a pulverizer with a diameter of 8 mmΦ mesh to produce a recovered single-layer film.

(Preparation of recovered resin composition pellets)
The respective recovered materials obtained above were dry blended and melt-kneaded so that the mass ratio of multilayer structure recovered material/monolayer film recovered material was 50/50. The melt kneading was carried out using a twin-screw segment extruder "2D30W2" manufactured by Toyo Seiki Seisakusho Co., Ltd. (D (mm) = 25, L/D = 30, screws: same direction fully meshing type), and the resin temperature was 220 ° C. The mixture was melt-kneaded to obtain recovered resin composition pellets (I) (cylindrical pellets with a diameter of 2 mm and a length of 4 mm).

(Preparation of multilayer film including recovered resin composition layer (recovered multilayer film))
Using a coextrusion multilayer cast film forming apparatus, the PO layer was made of 50 parts by mass of low-density polyethylene (LDPE; "Novatec (trademark) LJ400" manufactured by Japan Polyethylene Co., Ltd.) and 50 parts by mass of recovered resin composition pellets (I). The barrier layer is made of EVOH (C) ("EVAL (trademark) F171B" manufactured by Kuraray Co., Ltd.), and the adhesive layer is made of maleic anhydride-modified polyethylene (manufactured by Mitsui Chemicals Co., Ltd.). "ADMER (trademark) NF518") multilayer film (recovered resin composition layer/maleic anhydride modified polyethylene layer/EVOH layer/maleic anhydride modified polyethylene layer/recovered resin composition layer = 40 μm/5 μm/10 μm/5 μm/ A recovered multilayer film (5-layer coextruded multilayer cast film) having a layer thickness of 40 μm and a layer structure was produced. As a control, the PO layer was made of low-density polyethylene (LDPE; "Novatec (trademark) LJ400" manufactured by Japan Polyethylene Co., Ltd.), and the barrier layer was made of EVOH (C) ("EVAL (trademark) F171B" manufactured by Kuraray Co., Ltd.). The adhesive layer is a multilayer film (LDPE layer/maleic anhydride modified polyethylene layer/EVOH layer/maleic anhydride modified polyethylene layer/ A multilayer film (5-layer coextruded multilayer cast film) having a layer thickness and layer configuration of LDPE layer = 40 μm/5 μm/10 μm/5 μm/40 μm was formed. The extrusion processability of the pellet group containing recovered resin composition pellets (I) was stable and good. Furthermore, the recovered multilayer film had a good appearance with almost no difference in the amount of fish eyes and transparency compared to the multilayer film containing the LDPE layer.

Comparative example 12
A multilayer structure including a multilayer structure, a single layer film, recovered resin composition pellets, a recovered multilayer film, and a polyethylene layer was prepared in the same manner as in Example 39, except that the recovery aid pellets were not blended into the PO layer of the multilayer structure. A film was produced. Although the extrusion processability of the recovered composition was stable and good, the recovered multilayer film had increased fish eyes and decreased transparency compared to a multilayer film containing an LDPE layer.

Example 40
The layer thickness and layer structure of the recovered multilayer film are as follows: LDPE layer / recovered resin composition layer / maleic anhydride modified polyethylene layer / EVOH layer / maleic anhydride modified polyethylene layer / recovered resin composition layer / LDPE layer = 20 μm / 20 μm / 5 μm Recovery aid pellets and multilayer structure were prepared in the same manner as in Example 39, except that the recovered multilayer film (7-layer coextruded multilayer cast film) having the layer thickness and layer structure of /10μm/5μm/20μm/20μm was used. , a single layer film, a recovered resin composition pellet, a recovered multilayer film, and a multilayer film containing a polyethylene layer were produced. The extrusion processability of the pellet group containing recovered resin composition pellets (I) was stable and good. Furthermore, the recovered multilayer film had a good appearance with almost no difference in the amount of fish eyes and transparency compared to the multilayer film containing the LDPE layer.

Comparative example 13
A multilayer structure including a multilayer structure, a single layer film, recovered resin composition pellets, a recovered multilayer film, and a polyethylene layer was prepared in the same manner as in Example 40, except that the recovery aid pellets were not blended into the PO layer of the multilayer structure. A film was produced. Although the extrusion processability of the recovered composition was stable and good, the recovered multilayer film had increased fish eyes and decreased transparency compared to a multilayer film containing an LDPE layer.

Claims (12)

Polyolefin (A), ethylene-vinyl acetate copolymer composition (B) containing two or more ethylene-vinyl acetate copolymers having different ethylene unit contents, ethylene unit content 20 to 55 mol%, saponified The saponified ethylene-vinyl acetate copolymer composition (B) contains a saponified ethylene-vinyl acetate copolymer (C) having a saponification degree of 95 mol% or more and a fatty acid divalent metal salt (D), and the saponification degree of the ethylene-vinyl acetate copolymer composition (B) is A resin composition having an acid modification amount of 5 mol% or less and an acid modification amount of 0.01 mmol/g or less. The resin composition according to claim 1, wherein the ethylene unit content of the ethylene-vinyl acetate copolymer composition (B) is 50 to 90 mol%. In the two or more types of ethylene-vinyl acetate copolymers having different ethylene unit contents constituting the ethylene-vinyl acetate copolymer composition (B), the ethylene unit content of at least one set of ethylene-vinyl acetate copolymers The resin composition according to claim 1 or 2, wherein the difference is 5 to 50 mol%. Any one of claims 1 to 3, wherein the mass ratio (B/C) of the ethylene-vinyl acetate copolymer composition (B) and the saponified ethylene-vinyl acetate copolymer (C) is 0.05 to 2. The resin composition according to item 1. The resin according to any one of claims 1 to 4, wherein the mass ratio (B/D) of the ethylene-vinyl acetate copolymer composition (B) and the fatty acid divalent metal salt (D) is 3 to 100. Composition. The resin according to any one of claims 1 to 5, wherein the mass ratio (C/D) of the saponified ethylene-vinyl acetate copolymer (C) and the fatty acid divalent metal salt (D) is 10 to 1000. Composition. The difference in refractive index (AB) between the polyolefin (A) and the ethylene-vinyl acetate copolymer composition (B) satisfies 0.015 to 0.050, and the saponified ethylene-vinyl acetate copolymer composition (C ) and the ethylene-vinyl acetate copolymer composition (B), the difference in refractive index (C-B) satisfies 0.001 to 0.080, the resin composition according to any one of claims 1 to 6. thing. The content of the polyolefin (A) is 80 to 99% by mass, the content of the ethylene-vinyl acetate copolymer composition (B) is 0.10 to 6.0% by mass, and the content of the ethylene-vinyl acetate copolymer composition is 0.10 to 6.0% by mass. The content of the combined saponified product (C) is 0.10 to 20% by mass, and the content of the fatty acid divalent metal salt (D) is 0.005 to 0.50% by mass. The resin composition according to any one of the items. A step of melt-kneading a multilayer structure having a layer containing a polyolefin (A) as a main component and a layer containing a saponified ethylene-vinyl acetate copolymer (C) as a main component, the layers constituting the multilayer structure. 9. At least one layer of the ethylene-vinyl acetate copolymer composition (B) and the fatty acid divalent metal salt (D) contains at least one member selected from the group consisting of the ethylene-vinyl acetate copolymer composition (B) and the fatty acid divalent metal salt (D). A manufacturing method for manufacturing the described resin composition. The multilayer structure includes a layer containing polyolefin (A) as the main component and a layer containing saponified ethylene-vinyl acetate copolymer (C) as the main component, and at least one of the layers constituting the multilayer structure is ethylene-vinyl acetate copolymer. A multilayer structure used in the manufacturing method according to claim 9, comprising at least one member selected from the group consisting of a copolymer composition (B) and a fatty acid divalent metal salt (D). The step of mixing and melt-kneading a multilayer structure having a layer containing polyolefin (A) as a main component and a layer containing saponified ethylene-vinyl acetate copolymer (C) as a main component and a recovery aid, A method for producing a resin composition according to any one of claims 1 to 8, wherein the recovery aid comprises an ethylene-vinyl acetate copolymer composition (B) and a fatty acid divalent metal salt (D). A recovery aid used in the production method according to claim 11, comprising an ethylene-vinyl acetate copolymer composition (B) and a fatty acid divalent metal salt (D).