JPH04342749A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition capable of being extrusion molded in a molten state, having excellent flexibility, mixable with a resin of saponified material of olefin-vinyl acetate copolymer and a polyamide-based resins. CONSTITUTION:A polyvinyl alcohol-based copolymer resin obtained by subjecting a vinyl acetate monomer and an ethylene monomer to emulsion polymerization in the presence of >=3wt.% to <10wt.% polyvinyl alcohol based on total of polyvinyl alcohol and vinyl acetate monomer is blended with a polyvinyl alcohol- based resin. The mixture is optionally blended with a resin of a saponified material of olefin-vinyl copolymer or a polyamide-based resin.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition, and more particularly to a resin composition having good melt flowability and excellent flexibility.

0002

BACKGROUND OF THE INVENTION Polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) cannot be melt-extruded because its melting temperature and thermal decomposition temperature are extremely close. Also, PVA
The membrane is flexible and strong under high humidity conditions, but loses its flexibility under low humidity conditions and becomes brittle and easily torn.

As a method for solving this problem, a method is known in which α-olefin and vinyl acetate are copolymerized and saponified. For example, saponified ethylene-vinyl acetate copolymer (hereinafter referred to as EVO
(sometimes abbreviated as H) is known to be used. E
Although VOH can be melt-extruded, it is much more expensive than PVA and has poorer gas barrier properties than PVA under conditions of low humidity, which limits its use. In addition, since PVA cannot be melt-extruded, as a method for obtaining a film, for example, as disclosed in Poval P-374: Kobunshi Kankokai (published on April 25, 1984), PVA can be molded with water and glycol. Casting method in which PVA is dissolved with a plasticizer such as PVA and cast through a slit onto a drying drum or belt or applied by a roll coater and dried on a drum or belt to obtain a film. A method is used in which pellets are made by impregnating them with an appropriate amount of water and then extruded using an extruder equipped with special dissolving, kneading, and defoaming mechanisms. This extrusion molding is BRITISH POLYMER JOUR
NAL VOL. 20, NO. 4, P335 (1988
), a PVA solution is continuously formed in a twin-screw extruder, and the aqueous solution is introduced into a single-screw extruder, weighed under pressure while equalizing the temperature, filtered, and then extruded from a T-die.

[0004] As described above, molding PVA was extremely complicated, requiring a special molding machine, a filtration process to remove gel components, and a drying process to remove moisture from an aqueous solution after forming a film. . Therefore, it has been desired that it can be easily melt-molded like thermoplastic resins.

[0005] A method for making PVA melt-moldable and preventing it from becoming brittle is to add a plasticizer such as dipropylene glycol, triethylene glycol, diethylene glycol, or glycerin to PVA to lower its melting point or flow start temperature. It has been known. For this method,
R. K. Tubbs, J. Polymer. Sci, A.
3,4181 (1965) and Polymer Chemistry Vol. 26 P1
18 (1969) and others.

However, although this method is effective in lowering the flow initiation temperature, it also reduces gas barrier properties, generally reduces strength, and tends to absorb moisture and soften at high temperatures, while at low temperatures It had a tendency to become hard and brittle. There was also the problem that the plasticizer would bleed onto the surface of the molded product if stored for a long time.

[0007] Also, a method of mixing EVOH with PVA to make it melt moldable (Japanese Unexamined Patent Publication No. 49-33945), a saponified product of a long-chain α-olefin-vinyl acetate copolymer having 5 to 30 carbon atoms, A method of mixing so-called modified PVA with polymers excluding polyolefins (Japanese Patent Laid-Open No. 49-1175
36), a method of mixing bisphenols with modified PVA (Japanese Unexamined Patent Publication No. 50-123151), a method of grafting a polyolefin resin to PVA, and combining this grafted product with P
A method of mixing VA and polyolefin resin to make it melt moldable (Japanese Unexamined Patent Publication No. 188488/1988) has been known. However, all of these methods were inferior in melt moldability, uniform mixing properties, and gas barrier properties.

In order to solve the above problems, the present inventors first developed a state in which the polyvinyl alcohol resin and the polyvinyl alcohol were present in an amount of at least 10% by weight based on the total amount of the polyvinyl alcohol and vinyl acetate monomer. The ethylene content obtained by emulsion polymerization of vinyl acetate monomer and ethylene monomer is 1 to 5.
0% by weight polyvinyl alcohol copolymer resin 95~
A polyvinyl alcohol resin composition containing 5% by weight was investigated.

However, although this polyvinyl alcohol resin composition is particularly excellent in melt moldability, gas barrier properties, and stickiness on the surface of molded products, and also has good other properties, depending on the molded product, it may have even more flexibility. There may be cases where it is desired to further improve the

0010

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to obtain a resin composition that is more flexible than the above-mentioned polyvinyl alcohol resin composition. In this case, even if a product with better flexibility is obtained, there may be disadvantages such as a decrease in gas barrier properties and stickiness on the surface of the molded product. A second object of the present invention is to provide a saponified olefin-vinyl acetate copolymer with flexibility and improve impact resistance without causing stickiness on the surface of the molded product. A third object of the present invention is to improve the flexibility and other properties of polyamide resins by blending the resin composition with better flexibility obtained in the first object of the present invention.

[0011]

[Means for Solving the Problems] That is, the present invention provides (A
) Polyvinyl alcohol is 3% by weight or more and 10% by weight based on the total amount of polyvinyl alcohol and vinyl acetate monomer.
A polyvinyl alcohol copolymer resin with an ethylene content of 1 to 50% by weight, obtained by emulsion polymerization of vinyl acetate monomer and ethylene monomer, and (B) a polyvinyl alcohol resin of 95 to 95% by weight, A resin composition (composition I) comprising 5% by weight is provided. The present invention also provides the above (A) polyvinyl alcohol copolymer resin in an amount of 5 to 95% by weight and (B
) A resin composition prepared by blending 5 parts by weight or more of a composition comprising 95 to 5% by weight of a polyvinyl alcohol resin to 100 parts by weight of (C) a saponified olefin-vinyl acetate copolymer (Composition II ). Furthermore,
In the present invention, 5 parts by weight or more of a composition consisting of (A) 5-95% by weight of the polyvinyl alcohol copolymer resin and (B) 95-5% by weight of the polyvinyl alcohol-based resin, (
D) A resin composition (composition III) is provided, which is blended with 100 parts by weight of a polyamide resin.

In the resin composition I of the present invention, the polyvinyl alcohol copolymer resin used as component (A) contains polyvinyl alcohol in an amount of 3% by weight or more and less than 10% by weight based on the total amount of polyvinyl alcohol and vinyl acetate monomer. It refers to a polyvinyl alcohol copolymer resin with an ethylene content of 1 to 50% by weight, obtained by emulsion polymerization of vinyl acetate monomer and ethylene monomer.

Regarding the polyvinyl alcohol copolymer resin which is the component (A) of the present invention, for example,
It can be produced by the methods described in JP-A No. 96637, JP-A No. 63-108016, and the like. An example of a method for producing this polyvinyl alcohol copolymer resin is to copolymerize it with vinyl acetate monomer and ethylene monomer using a known catalyst in the presence of polyvinyl alcohol having an average degree of polymerization of 20 to 5,000. It will be done.

[0014] The polyvinyl alcohol used here may have any degree of hydrolysis, but preferably has an average saponification degree of 50 to 99%, particularly an average saponification degree of 70 to 99%.
% is more preferable. Especially, the average degree of saponification is 70~
99% and an average degree of polymerization of 100 to 3000 are preferable, and furthermore, an average saponification degree of 78 to 99% and an average degree of polymerization of 300 to 3000.
2500 is optimal.

During the copolymerization reaction of vinyl acetate monomer and ethylene monomer, the amount of polyvinyl alcohol present in the aqueous emulsion must be 3% by weight or more and less than 10% by weight based on the total amount of vinyl acetate monomer and polyvinyl alcohol. It is. If it is less than 3% by weight, the aqueous emulsion during the copolymerization reaction will become unstable, which is not preferable. Moreover, if it is more than 10% by weight, flexibility and mechanical strength may be impaired, which is not preferable especially when trying to improve these properties.

Furthermore, the ethylene content in the polyvinyl alcohol copolymer resin produced by the above method is 1
-50% by weight, preferably 10-45% by weight. If the ethylene content exceeds 50% by weight, the compatibility with the polyvinyl alcohol resin as component (B) and the gas barrier properties will be poor, making it unsuitable for the purpose of the present invention. On the other hand, 1% by weight
If it is less than that, it cannot be used because the melt moldability is poor.

The content of vinyl acetate units in the polyvinyl alcohol copolymer resin is not particularly limited, but is preferably from 1 to 89% by weight. If it is less than 1% by weight, melt moldability will be poor, and if it exceeds 89% by weight, problems such as compatibility with PVA and stickiness on the surface of the molded product may occur.

The above polyvinyl alcohol copolymer resin may be copolymerized with the following monomers in place of vinyl acetate monomer or ethylene monomer, or may be copolymerized with vinyl acetate monomer or ethylene monomer.
In addition to the ethylene monomer, a monomer having an ethylenically unsaturated bond can be copolymerized. Examples of these monomers include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, or their alkyl esters, and unsaturated carboxylic acids such as acrylamide, methacrylamide, and N-methylolacrylamide. Acid amide, styrene, acrylonitrile or functional group monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, α-olefins such as propylene, butene, decene, octadecene, vinyl propionate, butyric acid Examples include vinyl esters such as vinyl, vinyl pivalate, vinyl laurate, and vinyl versatate, and vinyl halides such as vinyl chloride and vinyl fluoride.

On the other hand, the polyvinyl alcohol resin which is the component (B) of the present invention refers to a partially or completely saponified product of polyvinyl acetate or a modified polyvinyl alcohol resin thereof. Polyvinyl acetate polymerization methods include bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. Among these, bulk polymerization is not preferred because it has problems such as an increase in the viscosity of the polymerization degree, adhesion of the polymer to the polymerization vessel, and difficulty in removing the heat of polymerization. On the other hand, in emulsion polymerization, the emulsion polymerized liquid is used directly as a raw material for adhesives, paints, etc., but it is not necessarily suitable as a method for producing polyvinyl acetate. Also,
Suspension polymerization has problems such as difficulty in controlling production conditions.

Therefore, the solution polymerization described below is generally suitably used as a method for producing polyvinyl acetate. In this solution polymerization, a method is adopted in which vinyl acetate monomer is diluted with a solvent such as methanol, ethanol, or methyl acetate, a catalyst is added, polymerization is performed, and the heat of polymerization is removed by the heat of evaporation of the solvent. Since solution polymerization has a low viscosity, it is easy to stir and remove the heat of polymerization. These polymerizations are usually carried out by methods using thermally decomposable initiators. Other methods include polymerization using ultraviolet rays, polymerization using radiation such as γ rays, and low-temperature polymerization using a redox catalyst. As an initiator that decomposes with heat, benzoyl peroxide (
BPO), azobisisobutyronitrile (AIBN), etc. are commonly used. The polyvinyl alcohol resin which is the component (B) of the present invention can be obtained by saponifying the polyvinyl acetate thus polymerized using an alkali catalyst or an acid catalyst.

[0021] The modified PVA resin refers to a partially or completely saponified copolymer as described below. For example, copolymers of vinyl acetate and olefins having 4 to 18 carbon atoms, copolymers of vinyl acetate and vinyl carboxylates (vinyl versatate, vinyl stearate, etc.), vinyl acetate and alkyl vinyl ethers (lauryl vinyl ether, methyl copolymers of vinyl acetate and (meth)acrylates (methyl methacrylate, etc.), vinyl acetate and acrylamide (acrylamide;
copolymers with vinyl acetate and unsaturated carboxylic acids or their anhydrides or esters (acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, etc.) Polymers, copolymers of vinyl acetate and sulfonic acid monomers (vinylsulfonic acid, acrylsulfonic acid, etc.), copolymers of vinyl acetate and cationic monomers (dimethylaminoethyl methacrylate, vinyl imidadol, vinyl pyridine, vinyl succinimide, etc.) These include copolymers, copolymers of vinyl acetate and other monomers (vinylene carbonate, allyl alcohol, allyl acetate, etc.).

[0022] The polyvinyl alcohol (PVA) thus obtained is composed of vinyl alcohol units and vinyl acetate units, and the degree of polymerization is not particularly limited and may be appropriately selected depending on the use etc. Usually 50
~2500 is good. In particular, in consideration of melt fluidity, mechanical strength, etc., those having a degree of polymerization of 200 to 1800 are preferred. On the other hand, the saponification degree is preferably 50 mol% or more, and in consideration of melt fluidity, the saponification degree is preferably 70 to 99.5 mol%. If the degree of saponification is less than 50 mol%, the mechanical strength will be poor, while if it exceeds 99.5 mol%, the melt fluidity will be poor.

The blending ratio of the polyvinyl alcohol copolymer resin as the component (A) and the polyvinyl alcohol resin as the component (B) of the present invention is 5% by weight to 95% by weight of the polyvinyl alcohol copolymer resin. % and polyvinyl alcohol-based resin in the range of 95% to 5% by weight, preferably polyvinyl alcohol-based copolymer resin 85%
~15% by weight and polyvinyl alcohol resin 15~8
It is 5% by weight. Further, in the resin composition I of the present invention, when a polyvinyl alcohol resin having a particularly low degree of polymerization is used, the melt fluidity tends to improve as the blending ratio of the polyvinyl alcohol resin increases. Here, if the blending ratio of the polyvinyl alcohol resin exceeds 95% by weight, melt moldability may be limited due to excessive melt fluidity. On the other hand, if it is less than 5% by weight, when a polyvinyl alcohol resin with a high degree of polymerization and a high degree of saponification is mixed, melt moldability will not be exhibited and it will not be usable.

Although the resin composition I of the present invention has better flexibility, it has some drawbacks such as gas barrier properties and stickiness on the surface of molded products. Therefore, as a result of various studies in an attempt to solve these drawbacks, we found that 5 parts by weight or more of the above resin composition I (i.e., a resin composition consisting of components (A) and (B)) was added to the olefin-vinyl acetate component (C). A resin composition (resin composition II) formed by blending with 100 parts by weight of the saponified copolymer,
It has been found that the high rigidity, which is a drawback of saponified olefin-vinyl acetate copolymers, can be made into a state of superior flexibility, and gas barrier properties and stickiness on the surface of molded products can be improved.

The saponified olefin-vinyl acetate copolymer, component (C) of the present invention, refers to a part of a copolymer of various olefins, such as ethylene, propylene, butene-1, etc., and vinyl acetate. Refers to all saponified products,
Examples include saponified ethylene-vinyl acetate copolymers, saponified propylene-vinyl acetate copolymers, and saponified ethylene-vinyl acetate copolymers (EVOH) are particularly preferred because they are easy to polymerize. There are various types of EVOH, but those having an ethylene content of 15 to 60 mol% and a saponification degree of 90 mol% or more are preferably used. If the ethylene content is less than 15 mol%, melt moldability may be reduced, and if the degree of saponification of the vinyl acetate component is less than 90 mol%, gas barrier properties may be reduced. Particularly preferably an ethylene content of 25 to 50 mol% and a saponification degree of 96
EVOH of mol % or more can be mentioned. In addition to ethylene and vinyl acetate (or saponified vinyl alcohol), unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and maleic acid, or their alkyl esters, as well as propylene, butene, α-decene, There is no problem even if a small amount of α-olefin such as α-octadecene is contained as a comonomer.

[0026] The above (A) in the resin composition II of the present invention
), (B) component and the saponified olefin-vinyl acetate copolymer that is component (C), the total amount of components (A) and (B) is 5 parts by weight or more, preferably 1 part by weight.
The amount is selected so as to be blended in an amount of 0 parts by weight or more with respect to 100 parts by weight of the saponified olefin-vinyl acetate copolymer as component (C). Note that the ratio of component (A) and component (B) here is 5 to 95% by weight of component (A) and (
It consists of 95 to 5% by weight of component B). If the total amount of components (A) and (B) is less than 5 parts by weight, gas barrier properties and mechanical strength will not be sufficiently developed, making it impossible to achieve the object of the present invention. However, (A) component and (B
) The upper limit of the blending ratio of the total amount of the components is not particularly limited and may be appropriately selected depending on the application. but,
Usually, the total amount of components (A) and (B) can be selected in the range of 5 to 1900 parts by weight based on 100 parts by weight of the saponified olefin-vinyl acetate copolymer, which is component (C). Most preferred.

Next, polyamide resins have poor flexibility and do not have sufficient gas barrier properties. Therefore, as a result of various studies, the present inventors found that the total amount of the above (A) component and (B) component is 5 parts by weight or more, and 100 parts by weight of the polyamide resin as the (D) component.
It has been found that resin composition III, which is blended in parts by weight, improves the flexibility, gas barrier properties, and other properties of polyamide resins.

There are various kinds of polyamide resins which are component (D), such as polyamide resins which are polycondensates of lactams, ε-amino acids, dibasic acids, and diamines. Specifically, ε-caprolactam, aminolactam, enantholactam, 11-aminoundecanoic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, α-
Polymers such as pyrrolidone and α-piperidone, diamines such as hexamethylene diamine, nonamethylene diamine, undecamethylene diamine, dodecamethylene diamine, metaxylylene diamine, and terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecane dibasic Examples include polycondensates with acids, dicarboxylic acids such as glutaric acid, and copolymers thereof. More specifically, nylon 4, nylon 6, nylon 7, nylon 8, nylon 11, nylon 12, nylon 6.6, nylon 6.
9, Nylon 6/10, Nylon 6/11, Nylon 6
-12, nylon MXD, etc. can be mentioned.

[0029] Regarding the blending ratio of the above-mentioned (A), (B) components and the polyamide resin which is the (D) component in the resin composition III of the present invention, the total amount of the (A) component and (B) component is 5. At least 10 parts by weight, preferably at least 10 parts by weight,
It is selected so as to be blended with respect to 100 parts by weight of the polyamide resin which is the component (D). Note that the ratio of component (A) and component (B) here is 5 to 9 as described above.
5% by weight and 95 to 5% by weight of component (B). If the total amount of components (A) and (B) is less than 5 parts by weight, gas barrier properties and mechanical strength will not be sufficiently developed, making it impossible to achieve the object of the present invention. However, the upper limit of the total blending ratio of component (A) and component (B) is not particularly limited and may be appropriately selected depending on the application. However, polyamide resin 100, which is component (D), is usually
Most preferably, the total amount of component (A) and component (B) is selected in the range of 5 to 1900 parts by weight.

Resin compositions I, II and III of the present invention
The melting index (MFR, according to JIS-K6758. Load 2.16 kg, temperature 230°C) is not particularly limited and may be selected depending on the molding method, but depending on extrusion molding it may be 0.1 to 50. A range of is appropriate.

The resin composition of the present invention can be molded into films, sheets, bottles, etc. by known melt molding methods and compression molding methods. Although the composition of the present invention formed into a film or sheet can be used as it is, it is also effective to further laminate it with other layers and use it as a multilayer laminate. For example, such a lamination method includes so-called dry lamination molding, in which other thermoplastic resin layers are laminated on a single-layer product of the resin composition of the present invention using a polyurethane-based or polyacrylic-based dry lamination adhesive. Is it done by law or sand lamination method?
Alternatively, various methods such as coextrusion lamination method, coextrusion method (feed block, multi-manifold method), co-injection molding method, co-extrusion pipe molding method, and solution coating molding method in which the resin composition of the present invention is dissolved in a solvent and coated. There is.

The multilayer laminate thus obtained may be further heated and stretched using a vacuum forming machine, compression molding machine, stretch blow molding machine, etc., or the above multilayer laminate may be uniaxially or A heating stretching operation can be performed using a biaxial stretching machine. Other thermoplastic resins to be laminated to the resin composition of the present invention include polyethylene resins, polypropylene resins, copolymers of ethylene and α-olefins having 3 to 12 carbon atoms, polyolefin resins such as ionomer resins, polystyrene resins, Thermoplastic resins include polyethylene terephthalate resin, polyvinyl chloride resin, polycarbonate resin, and polyamide resin. Copolymers of ethylene and α-olefin having 3 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-4 methylpentene-1 copolymer, ethylene-hexene-1 copolymer, and ethylene-1 copolymer. Modified polypropylene blended with propylene rubber, modified polybutene, modified poly-4-methylpentene, or the above-mentioned polyolefin polymers are grafted with unsaturated carboxylic acids or their anhydrides in the presence of organic peroxides, or with other monomers ( For example, those copolymerized with methyl methacrylate, ethyl acrylate, etc.) are also included.

The layer structure of the multilayer laminate is as follows: (a) layer is the resin composition of the present invention, (b) layer is the adhesive resin layer, and (c) layer is the other thermoplastic resin. (b) layer/(c
) layer, (c) layer / (b) layer / (a) layer / (b) layer / (c
) layer, (c) layer/(b) layer/metal foil/(a) layer/(b)
Typical examples include layer/(c) layer. The thermoplastic resins for both outer layers may be different, or the same resin may be used. As the adhesive resin layer, the so-called dry lamination adhesives such as the aforementioned polyurethane adhesives, polyacrylic adhesives, polyester adhesives, etc., and adhesive resins known in the coextrusion molding method can be used. For example, such a resin layer may include a resin obtained by grafting or copolymerizing a polyolefin resin with an unsaturated carboxylic acid, acid anhydride, or ester monomer.

[0034] Examples of the grafting method at this time include a method in which a polyolefin resin is modified by melt grafting with an organic peroxide and the above components, or a method in which a polyolefin resin is dissolved in hot xylene and the above components are grafted with an organic peroxide. be. Unsaturated carboxylic acids, acid anhydrides, and ester monomers include methacrylic acid, acrylic acid, ethacrylic acid, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, diethyl maleate, and monoethyl maleate. , di-n-butyl maleate, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, itaconic acid, itaconic anhydride, 5-norbornene-2,3-anhydride, citraconic acid, citraconic anhydride Examples include crotonic acid, crotonic anhydride, acrylonitrile, methacrylonitrile, sodium acrylate, calcium acrylate, and magnesium acrylate. Regarding these graft polymers, U.S. Pat.
6967 specification and US Pat.
It is described in detail in Publication No. 23, Japanese Patent Publication No. 49-4822, etc.

[0035] The blending method for obtaining the resin composition of the present invention is not particularly limited, and a ribbon blender,
It is preferable to pelletize and dry using a high-speed mixer, kneader, pelletizer, mixing roll, etc. Alternatively, each component may be directly supplied to a molding machine for molding.

The resin composition of the present invention can generally contain other additives commonly used in thermoplastic resins. Examples of such additives include 2,5-di-
t-butylhydroquinone; 2,6-di-t-butyl-
p-cresol; 4,4'-thiobis(6-t-butylphenol); 2,2-methylene-bis(4-methyl-
6-t-butylphenol); octadecyl-3-(3
',5'-di-t-butyl-1'-hydroxyphenyl) propionate; 4,4'-thiobis(6-butylphenol), etc. Ethyl-2-cyano-3,3-diphenylacrylate as a UV absorber; 2 -(2'-hydroxy-5-methylphenyl)benzotriazole;
2-hydroxy-4-octoxybenzophenone, etc.
dimethyl phthalate; glycerin; dipropylene glycol; triethylene glycol; diethylene glycol diethyl phthalate; wax; liquid paraffin; polyethylene oxide; carbowax, etc.; ethylene bisstearamide as a lubricant; butyl stearate, etc.; carbon black as a coloring agent; phthalocyanine; quinacridone; indoline; azo pigment; titanium oxide; red iron oxide, etc.; glass fiber as a filler;
Asbestos; mica; ballastonite; calcium silicate; aluminum silicate; calcium carbonate, etc. Moreover, many other polymeric compounds can also be blended to the extent that the effects of the present invention are not inhibited.

[0037]

[Function] The reason why the flexibility of the resin composition is further improved in the resin composition of the present invention is not clear, but by mixing both the polyvinyl alcohol copolymer resin and the polyvinyl alcohol resin, it is possible to As a result, the polyvinyl alcohol resin becomes melt-flowable and has excellent mechanical strength. By blending the resin composition consisting of components (A) and (B) of the present invention with a saponified olefin-vinyl acetate copolymer, which is component (C), the resulting composition can be molded. When molded, pinholes, cracks, uneven thickness, etc. do not occur, and the molded product has excellent flexibility. Moreover, the containers etc. that are formed have excellent barrier properties. The reason why the conventional problems can be solved in this way is not clear, but (A) of the present invention
The resin composition consisting of component and component (B) is highly flexible,
And because it has excellent compatibility with the saponified olefin-vinyl acetate copolymer and the polyamide resin, it is suitable for the saponified olefin-vinyl acetate copolymer as the component (C) and the polyamide resin as the component (D). It is presumed that these two materials complement each other's shortcomings without impairing their inherent characteristics.

[0038]

【Example】

Hereinafter, the present invention will be explained in more detail with reference to Examples. Examples 1 to 16 and Comparative Examples 1 to 6

(1) (Preparation of polyvinyl alcohol copolymer resin) Using an autoclave with a capacity of 30 liters, PVA205 manufactured by Kuraray Co., Ltd., which is a partially saponified polyvinyl alcohol resin with a degree of polymerization of 500 and a degree of saponification of 88%, was used. (trade name), the ratio of PVA and vinyl acetate monomer was changed as shown in Table 1, and while ammonium persulfate and sodium metabisulfite were added as catalysts, the concentration of vinyl acetate and the pressure of ethylene gas were adjusted. Emulsion polymerization was carried out by changing the formula to obtain polyvinyl alcohol copolymer resins having ethylene contents shown in Table 1. The solids concentration of the polymerized emulsion was about 20-60% by weight. This emulsion was allowed to stand at -20°C for 20 hours to undergo freeze precipitation to obtain a polymer (polyvinyl alcohol copolymer resin). The obtained polymer was then freeze-pulverized, freeze-dried, and vacuum-dried at a temperature of 80°C. Incidentally, the proportion of ethylene component in the polymer was determined by an alkali saponification method.

[0040]

[Table 1]

(2) (Mixture of polyvinyl alcohol copolymer resin and polyvinyl alcohol resin) Above (1)
The polyvinyl alcohol copolymer resin obtained in ) and the specified polyvinyl alcohol resin were thoroughly mixed using a super mixer manufactured by Kawada Co., Ltd., and then a 30 mm twin screw extruder manufactured by Nakatani Kikai Co., Ltd. Mix at a temperature of 220°C using
A resin composition shown in Table 2 was obtained. The resin composition obtained in this way was processed using a melt indexer manufactured by Takara Industries.
MFR was measured at a temperature of 230° C. according to JIS-K6758. Next, a film with a thickness of 50 μm was formed using a 40 mm T-die forming machine manufactured by Yoshii Iron Works.

(3) (Mixing of saponified ethylene-vinyl acetate copolymer or polyamide resin and the resin composition obtained in (2) above) Using the above mixer and extruder, at a temperature of 230°C. The resin composition (modified PVA) obtained in (2) above was mixed with 100 parts by weight of saponified ethylene-vinyl acetate copolymer (EVOH) or polyamide resin at a predetermined ratio. In the same manner as above, a film with a thickness of 50 μm was formed using a 40 mm T-die forming machine manufactured by Yoshii Iron Works, and the following physical properties were evaluated. Regarding the resin composition or film produced as described above, using a melt indexer manufactured by Takara Industries,
MFR measurements were performed at a temperature of 230° C. according to IS-K6758. On the other hand, for the film, a Toyo Sokki Tensilon UTM-III type tensile tester was used to test the JIS-Z
Tensile test according to 1702 and ASTM D-88
2, and the amount of oxygen permeation was measured using OXTRAN-10/50A manufactured by Modern Control. These results are also shown in Tables 2 and 3.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Effects of the Invention] The resin composition I of the present invention has extremely good flexibility. Furthermore, the resin composition II of the present invention has good gas barrier properties and extremely good flexibility. Furthermore, the resin composition III of the present invention has excellent flexibility and has improved gas barrier properties of the polyamide resin. Therefore, the resin composition of the present invention can be effectively used as containers for food packaging materials, pharmaceutical packaging materials, cosmetic packaging materials, and the like.

Claims (5)

[Claims] Claim 1: (A) Polyvinyl alcohol is 3% of the total amount of polyvinyl alcohol and vinyl acetate monomer.
A polyvinyl alcohol copolymer resin having an ethylene content of 1 to 50% by weight and 5 to 95% by weight obtained by emulsion polymerization of vinyl acetate monomer and ethylene monomer in the presence of 5% to 95% by weight and (B) A resin composition comprising 95 to 5% by weight of a polyvinyl alcohol resin. Claim 2: (A) Polyvinyl alcohol is 3% of the total amount of polyvinyl alcohol and vinyl acetate monomer.
A polyvinyl alcohol copolymer resin having an ethylene content of 1 to 50% by weight and 5 to 95% by weight obtained by emulsion polymerization of vinyl acetate monomer and ethylene monomer in the presence of 5% to 95% by weight and (B) A resin composition comprising 5 parts by weight or more of a resin composition comprising 95 to 5% by weight of a polyvinyl alcohol resin, based on 100 parts by weight of (C) a saponified olefin-vinyl acetate copolymer. Claim 3: (A) Polyvinyl alcohol is 3% relative to the total amount of polyvinyl alcohol and vinyl acetate monomer.
A polyvinyl alcohol copolymer resin having an ethylene content of 1 to 50% by weight and 5 to 95% by weight obtained by emulsion polymerization of vinyl acetate monomer and ethylene monomer in the presence of 5% to 95% by weight and (B) A resin composition comprising 5 parts by weight or more of a resin composition comprising 95 to 5% by weight of a polyvinyl alcohol resin, based on 100 parts by weight of (D) a polyamide resin. 4. The polyvinyl alcohol resin of component (B) is composed of vinyl alcohol units and vinyl acetate units, has a degree of polymerization of 50 to 2500, and a degree of saponification of 50 mol%.
The resin composition according to any one of claims 1 to 3, which is the above. 5. The resin composition according to claim 2, wherein the saponified olefin-vinyl acetate copolymer as component (C) has an ethylene content of 15 to 60 mol% and a saponification degree of 90 mol% or more.