JP7577925B2 - Hydrolyzate and laminate - Google Patents

Description

The present invention relates to a hydrolysate that has excellent adhesion to both thermoplastic resins with few polar groups and EVOH, has few foreign matter such as fish eyes and gel-like substances, and has an excellent appearance, and to a laminate that includes the hydrolysate as an intermediate layer.

Ethylene-vinyl alcohol copolymers (hereinafter referred to as "EVOH") are excellent in gas barrier properties, aroma retention, solvent resistance, and the like, and are therefore used as packaging materials for foods, beverages, medicines, and the like to prevent deterioration of the contents.
EVOH is hydrophilic and its gas barrier properties and the like deteriorate due to moisture absorption, so it is generally used as an intermediate layer in laminates of thermoplastic resins having excellent water resistance, such as polyethylene and polypropylene.

However, since EVOH has many hydroxyl groups in its molecules, its affinity with thermoplastic resins that do not have polar groups is extremely low, and the two generally do not adhere to each other. For this reason, it is known to insert, as an intermediate layer between the EVOH and the thermoplastic resin, a laminate using a graft-modified ethylene-based resin composition grafted with an unsaturated carboxylic acid or its derivative (Patent Documents 1 and 2), or a composition of an ethylene-vinyl acetate copolymer, a saponified ethylene-vinyl acetate copolymer, and a tackifier (Patent Document 3), and to use the intermediate layer as an adhesive layer.

The compositions disclosed in Patent Documents 1 and 2 have excellent adhesive properties. However, when the compositions are repeatedly kneaded, the resin remaining in the extruder or die increases in viscosity and becomes discolored and gelled, resulting in the presence of numerous fish eyes and gel-like substances in the product, which poses a problem in appearance.
On the other hand, the saponified ethylene-vinyl acetate copolymer disclosed in Patent Document 3 does not discolor or gel when repeatedly kneaded, and furthermore, because an adhesive resin is added, the adhesiveness to EVOH is improved. However, the adhesive strength is not sufficient, and peeling often occurs when small impacts or friction are applied during transportation or use, and there was an issue with the adhesive strength.

As a method to solve the problem of low adhesion, a technology has been disclosed that uses a hydrolysate of a resin composition containing ethylene-vinyl acetate copolymers with different vinyl acetate contents and their graft-modified products. The hydrolysate has good adhesion and exhibits a certain level of performance in terms of appearance, but further improvement is desired.

Japanese Unexamined Patent Publication No. 61-270155 Japanese Unexamined Patent Publication No. 62-158043 Japanese Unexamined Patent Publication No. 7-108655 Patent Publication 2017-210608

The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a hydrolysate that has excellent adhesion to both a thermoplastic resin with few polar groups and EVOH, has few foreign matters such as fish eyes and gel-like substances, and has an excellent appearance, and a laminate that includes the hydrolysate as an intermediate layer.

As a result of intensive research aimed at solving the above problems, the inventors discovered that a hydrolyzate obtained by hydrolyzing a composition containing specific components is less susceptible to contamination with foreign matter and has excellent adhesion to a layer containing a thermoplastic resin and an EVOH layer, thereby solving the present invention.

That is, the present invention relates to a hydrolysate of a melt-kneaded product comprising: a copolymer (A) of ethylene and a vinyl ester having a vinyl ester content of 3.5 mol % or more and 7.0 mol % or less; a copolymer (B) of ethylene and a vinyl ester having a vinyl ester content of 17 mol % or more and 75 mol % or less; a compatibilizer (C); a crosslinking agent (D); and a thermoplastic resin (E) that satisfies the following requirements (1) and (2):
(1) The vinyl ester content is less than 3.5 mol %.
(2) The melt mass flow rate at 190°C under a load of 2.16 kg is higher than the melt mass flow rate of a copolymer (A) of ethylene and a vinyl ester having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less, and the melt mass flow rate of a copolymer (B) of ethylene and a vinyl ester having a vinyl ester content of 17 mol% or more and 75 mol% or less.

The present invention provides a hydrolysate that has excellent adhesion to thermoplastic resins with few polar groups and EVOH, and combines mechanical properties and appearance, and is suitable for use in food packaging and sanitary packaging, as well as a laminate having a layer of the hydrolysate.

The resin composition, which is one aspect of the present invention, is described in detail below.

The hydrolysate of the present invention is a hydrolysate of a melt-kneaded product containing (A) a copolymer of ethylene and a vinyl ester having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less, (B) a copolymer of ethylene and a vinyl ester having a vinyl ester content of 17 mol% or more and 75 mol% or less, (C) a compatibilizer, (D) a crosslinking agent, and (E) a thermoplastic resin that satisfies the following requirements (1) and (2) (hereinafter referred to as "the hydrolysate of the present invention").
(1) The vinyl ester content is less than 3.5 mol %.
(2) The melt mass flow rate at 190°C under a load of 2.16 kg is higher than the melt mass flow rate of a copolymer (A) of ethylene and a vinyl ester having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less, and the melt mass flow rate of a copolymer (B) of ethylene and a vinyl ester having a vinyl ester content of 17 mol% or more and 75 mol% or less.

More specifically, the composition of the present invention is a product obtained by hydrolysis treatment (hereinafter also referred to as "hydrolysate") of a composition containing a graft modified product (hereinafter also referred to as "graft modified product") of an ethylene and vinyl ester copolymer (A) having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less, an ethylene and vinyl ester copolymer (B) having a vinyl ester content of 17 mol% or more and 75 mol% or less, a compatibilizer (C), and a specific thermoplastic resin (E).
The graft modified product can be, for example, a product obtained by subjecting the compositions (A), (B), (C), and (E) to a crosslinking treatment. Examples of the crosslinking treatment include a method in which a crosslinking agent such as a peroxide is added to the composition and the composition is melt-kneaded, and a method in which electron beam irradiation is used. The graft modified product is preferably a product that has been subjected to a melt-kneading method.

In the present invention, the copolymer (A) of ethylene and vinyl ester having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less (hereinafter referred to as component (A)) is specifically a copolymer having ethylene residue units and vinyl ester residue units.

The vinyl esters in component (A) include aliphatic vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, and vinyl stearate, and aromatic vinyl esters such as vinyl benzoate. From the viewpoint of cost, component (A) is preferably an ethylene-vinyl acetate copolymer.

From the viewpoint of adhesion with the thermoplastic resin layer when laminated, the vinyl ester content of component (A) is 3.5 mol% or more and 7.0 mol% or less, and most preferably 4.5 mol% or more and 6.5 mol% or less.

When components (B), (C), and (E) described below are copolymers of ethylene and vinyl ester, component (A) differs from the other components in at least one of the vinyl ester content, melt mass flow rate, and density. The vinyl ester content of component (A) is less than that of component (B). It is also preferable that the vinyl ester content of component (A) is less than that of component (C) and more than that of component (E).

The melt mass flow rate (hereinafter referred to as "MFR") of component (A) at 190°C under a load of 2.16 kg is preferably 0.5 g/10 min or more and 40 g/10 min or less, and most preferably 3 g/10 min or more and 35 g/10 min or less.

The method for producing the ethylene-vinyl acetate copolymer in component (A) is not particularly limited as long as it is possible to produce the ethylene-vinyl acetate copolymer, but examples include known production methods such as high-pressure radical polymerization, solution polymerization, and latex polymerization. Such resins can be conveniently selected from commercially available products, and are commercially available from Tosoh Corporation under the name Ultrathene.

In the present invention, examples of the copolymer (B) of ethylene and vinyl ester having a vinyl ester content of 17 mol % or more and 75 mol % or less (hereinafter referred to as component (B)) include aliphatic vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, and vinyl stearate, and aromatic vinyl esters such as vinyl benzoate, but from the viewpoint of cost, ethylene-vinyl acetate copolymers are preferred.

The vinyl ester content of component (B) is from 17 mol% to 75 mol%, and most preferably from 17 mol% to 40 mol%, in order to further improve the adhesion between the hydrolyzate of the present invention and EVOH.

The MFR of component (B) at 190°C under a load of 2.16 kg is preferably 0.5 g/10 min or more and less than 75 g/10 min.

The method for producing the ethylene-vinyl acetate copolymer in component (B) is not particularly limited as long as it is possible to produce the ethylene-vinyl acetate copolymer, but examples include known production methods such as high-pressure radical polymerization, solution polymerization, and latex polymerization. Such resins can be conveniently selected from commercially available products, and are commercially available under the trade names Ultrathene from Tosoh Corporation and Levaprene and Levamelt from Lanxess KK.

The graft modified product of the present invention before the hydrolysis treatment of the hydrolyzate further contains a compatibilizer (C) (hereinafter referred to as "component (C)") in addition to components (A) and (B).
Component (C) is added to enhance the dispersibility of components (A) and (B).

Component (C) is preferably a copolymer of ethylene and a vinyl ester, in which case component (C) has a higher vinyl ester content than component (A) and a lower vinyl ester content than component (B).
The vinyl ester content of component (C) is preferably in the range of 7.5 mol % or more and 16 mol % or less.

Examples of vinyl esters of component (C) include aliphatic vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, and vinyl stearate, and aromatic vinyl esters such as vinyl benzoate.

When component (C) contains a copolymer of ethylene and a vinyl ester, the polymer may be used alone or in a composition containing two or more types of copolymers, but it is preferable to use two or more types of copolymers of ethylene and a vinyl ester. This improves the dispersibility of components (A) and (B), improves the adhesion of the hydrolyzate of the present invention to thermoplastic resins and EVOH, and also contributes to reducing fish eyes and gels.

When component (C) is a composition containing at least two types of copolymers of ethylene and vinyl ester, at least one of the vinyl ester content, melt mass flow rate, and density of each component of the composition is different. Preferably, the vinyl ester content of each component of the composition is different.

When two or more types of copolymers of ethylene and vinyl ester are used as the compatibilizer (C), the difference in the content of each vinyl ester is preferably within 8 mol%, and most preferably within 5 mol%.

The preferred blend ratio of components (A), (B), and (C) in the saponification product is 4 to 95 parts by weight of component (A), 4 to 95 parts by weight of component (B), and 1 to 50 parts by weight of component (C) (the total of (A), (B), and (C) is 100 parts by weight), since it reduces foreign matter such as fish eyes and gels and improves adhesion to the thermoplastic resin and EVOH of the present application. More preferably, component (A) is 15 to 90 parts by weight, component (B) is 5 to 75 parts by weight, and component (C) is 5 to 45 parts by weight, and even more preferably, component (A) is 15 to 80 parts by weight, component (B) is 15 to 50 parts by weight, and component (C) is 5 to 40 parts by weight.

The graft modified product of the present invention before the hydrolysis treatment of the hydrolyzate further contains a thermoplastic resin (E) (hereinafter referred to as "component (E)") in addition to components (A), (B), and (C).

Component (E) can be a polyolefin, more specifically a homopolymer of an α-olefin having 2 to 12 carbon atoms, such as ethylene, propylene, or 1-butene, a copolymer of the olefin, an ethylene-vinyl ester copolymer, or an ethylene-acrylic acid ester copolymer.

Component (E) is preferably a copolymer of ethylene and a vinyl ester. Here, when the aforementioned components (A), (B), and (C) are copolymers of ethylene and a vinyl ester, component (E) differs from the other components in at least one of the vinyl ester content, melt mass flow rate, and density. Preferably, the vinyl ester content of component (E) is different from the vinyl ester content of the other components, and the vinyl ester content of component (E) is preferably less than the vinyl ester content of any of components (A), (B), and (C).

Specifically, the vinyl ester content in component (E) is preferably in the range of 0.1 mol% to 3.4 mol%.

The MFR of component (E) at 190°C under a load of 2.16 kg is higher than that of both component (A) and component (B). The MFR of component (E) is preferably 75 g/10 min or more.

Examples of component (E) include ethylene-based polymers such as high-pressure low-density polyethylene, high-density polyethylene, medium-density polyethylene, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, and ethylene-methacrylic acid ester copolymer, polypropylene, propylene-ethylene copolymer, propylene-1-butene copolymer, poly-1-butene, poly-1-hexene, and poly-4-methyl-1-pentene. Thermoplastic resin (E) may be used alone or in combination of two or more.

Among these, from the viewpoints of adhesion of the hydrolyzate of the present invention to thermoplastic resins such as polyethylene and polypropylene, and cost, at least one of the group consisting of high-pressure low-density polyethylene, high-density polyethylene, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-vinyl acetate copolymer, and polypropylene is most preferred.

The method for producing high-pressure low-density polyethylene can be exemplified by high-pressure radical polymerization, and such resins can be conveniently selected from commercially available products, for example, those available from Tosoh Corporation under the trade name Petrocene. The methods for producing high-density polyethylene, ethylene-1-butene copolymer, and ethylene-1-hexene copolymer are not particularly limited, and examples include high-, medium-, and low-pressure ionic polymerization methods using Ziegler-Natta catalysts, Phillips catalysts, and metallocene catalysts, and such resins can be conveniently selected from commercially available products, for example, those available from Tosoh Corporation under the trade names Nipolon Hard, Nipolon-L, and Nipolon-Z.

The method for producing ethylene-vinyl acetate copolymer is not particularly limited as long as it is possible to produce a copolymer of ethylene and vinyl ester, but examples include the well-known high-pressure radical polymerization method and ionic polymerization method. An ethylene-vinyl acetate copolymer produced by high-pressure radical polymerization method is commercially available from Tosoh Corporation under the product name Ultrathene.

There is no particular limitation on the method for producing polypropylene, but for example, it can be obtained by polymerizing propylene or copolymerizing propylene with one or more other α-olefins in the presence of a single-site catalyst, typically a catalyst formed from a solid titanium catalyst component and an organometallic compound catalyst component, or a catalyst formed from both of these components and an electron donor, or a metallocene catalyst. Such resins can be conveniently selected from commercially available products. For example, they are commercially available from Japan Polypropylene Corporation under the trade names Novatec and Wintech, respectively.

The amount of component (E) added is preferably 0.1 parts by weight or more and 40 parts by weight or less per 100 parts by weight of the total of components (A), (B), and (C).

The hydrolyzate of the present invention is obtained by hydrolyzing a graft modified product obtained by crosslinking the compositions (A), (B), (C), and (E). Examples of the crosslinking treatment include a method of adding a crosslinking agent such as a peroxide to the composition and melt-kneading the composition, and a method of irradiating the composition with an electron beam. The graft modified product is preferably one that has been treated by melt-kneading. When using the melt-kneading method, it is preferable to include a crosslinking agent (hereinafter referred to as component (D)).

The component (D) is not particularly limited as long as it is an organic peroxide, and examples thereof include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,1-di(t-butylperoxy)cyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 1,3-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,3-di-(t-butylperoxy)-diisopropylbenzene, n-butyl-4,4-bis(t-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxybenzoate, t-butylperoxyisopropylcarbonate, diacetyl peroxide, lauroyl peroxide, and t-butylcumyl peroxide. These can be used alone or in combination of two or more.
Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 1,1-di(t-butylperoxy)cyclohexane are preferably used from the viewpoint of reactivity, and such crosslinking agents (D) can be conveniently selected from commercially available products, and are commercially available from NOF Corporation under the trade names PERHEXA 25B and PERHEXA C, respectively.

In addition, in order to improve the dispersibility of the crosslinking agent during melt kneading, the crosslinking agent (D) may be impregnated into any of components (A), (B), and (C).

Furthermore, together with the crosslinking agent (D), a crosslinking assistant such as triallyl isocyanurate or divinylbenzene may be used, if necessary.
The amount of the crosslinking agent (D) is preferably in the range of 0.005 part by weight to 1 part by weight based on 100 parts by weight in total of the components (A), (B) and (C), which is preferable from the viewpoint of improving the adhesion of the hydrolyzate of the present invention to EVOH and also from the viewpoint of moldability.

In the present invention, a specific example of a manufacturing process for obtaining a melt-kneaded product containing a graft-modified product is as follows:

The dry blend of components (A) to (E) is fed into the hopper of an extruder. At this time, at least a portion of components (A) to (E) may be added from a side feeder or the like. Furthermore, two or more extruders may be used to sequentially melt-knead the components in stages. A Henschel mixer, V blender, ribbon blender, tumbler, or the like may be used to dry blend components (A) to (E).

In addition to the above-mentioned components, additives such as crosslinking aids, antioxidants, lubricants, neutralizing agents, antiblocking agents, surfactants, slip agents, etc., which are normally used in polyolefins such as polyethylene and polypropylene, may also be added as necessary.

The method of melt-kneading components (A) to (E) is not particularly limited as long as the melt-kneading device can uniformly disperse each component, and production can be performed using a commonly used resin mixing device. Examples of melt-kneading devices include single-screw extruders, multi-screw extruders, Banbury mixers, pressure kneaders, and rotating rolls. Among these, twin-screw extruders, which have a high degree of kneading and can be operated continuously, are preferred because they can achieve a fine and uniform dispersion state. The melting temperature is preferably in the range of the melting point of component (A) to about 260°C. By melt-kneading at the above temperature, a melt-kneaded product containing a graft modified product can be obtained.

In terms of productivity, the hydrolysis method for obtaining the hydrolyzate of the present invention is preferably a direct hydrolysis treatment of pellets or powder of the melt-kneaded product containing the graft modified product in an alkali. As the alkali, it is preferable to use an alcohol solution in which sodium hydroxide is dissolved. As the alcohol, it is preferable to use methanol, which is excellent in terms of cost, and the concentration of sodium hydroxide is preferably adjusted in the range of 0.1 to 10% by weight. The temperature of the hydrolysis treatment is appropriately set depending on the desired degree of saponification, and when methanol is used as the alcohol, it is preferably adjusted in the range of 30 to 65°C under normal pressure conditions. If hydrolysis does not proceed easily under normal pressure conditions, it may be performed under pressurized conditions.

The degree of saponification can be determined from the difference in vinyl ester content between the molten kneaded product and the hydrolyzate, and the vinyl ester content can be measured in accordance with JIS K7192 (1999).

The hydrolyzate of the present invention is preferably one in which the degree of saponification of the vinyl ester component of the melt-kneaded product containing components (A) to (E) is 10% by weight or more. If it is 10% by weight or more, the adhesion to EVOH is sufficient.

The hydrolysate of the present invention can be used in any form, such as pellets or powder.

The laminate, which is one aspect of the present invention, is described in detail below.

The hydrolysate of the present invention may be used as a laminate (hereinafter referred to as the "laminate of the present invention") consisting of a layer of the hydrolysate and at least one layer of another material.

The laminate of the present invention is preferably a laminate having a layer made of the hydrolyzate and at least one layer of a thermoplastic resin group, such as polyolefins such as polyethylene and polypropylene, polyesters such as polylactic acid and polybutylene terephthalate, polyamides such as nylon, and EVOH. It may also have a laminate structure having a combination of two or more of these groups or a combination of various resin layers. In particular, from the viewpoints of cost and moldability, those having a thermoplastic resin with few polar groups, such as polyethylene or polypropylene, and EVOH are preferred.

Preferably, the laminate is laminated in the order of an outer layer made of a thermoplastic resin having few polar groups/a layer of the hydrolyzate of the present invention/an EVOH layer, and more preferably, an outer layer made of a thermoplastic resin having few polar groups/a layer of the hydrolyzate of the present invention/an EVOH layer/a layer of the hydrolyzate of the present invention/an inner layer made of a thermoplastic resin having few polar groups. The laminate of the present invention can be molded using a normal molding device, and examples of the molding method include any method such as extrusion molding, blow molding, sheet molding, injection molding, compression molding, calendar molding, and vacuum molding, and can be molded into a sheet, film, pipe, block, or other arbitrary shape. By adopting a laminate structure with other materials, it is possible to impart the properties of the other materials, such as gas barrier properties, mechanical properties, oil resistance, and weather resistance, to the laminate.

The laminate of the present invention can be used for packaging materials and containers made of thermoplastic resins for foods, beverages, medicines, and other items that require these properties.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[Melt mass flow rate (MFR)]
Measurement was performed in accordance with JIS K6922-1 (1997).
[Saponification degree]
Each of the hydrolysates obtained in the examples was measured in accordance with JIS K7192 (1999).
[Film appearance]
A monolayer film having a thickness of 50 μm was produced using each hydrolyzate obtained in the examples. The monolayer film was produced using a monolayer cast film molding machine (manufactured by Sumiju Modern Co., Ltd.) at a set temperature of 200° C. The obtained monolayer film was cut into a size of 10 cm x 10 cm, and the presence or absence of fish eyes of 0.3 mm or more in the film was observed. If there were 100 or more fish eyes (foreign matter) of 0.3 mm or more, the film was marked with "X", if there were 50 or more but less than 100, the film was marked with "△", and if there were less than 50, the film was marked with "O".
[Interlayer adhesive strength (peel strength)]
Using each hydrolyzate obtained in the examples, a three-kind five-layer film including a thermoplastic resin layer (polyethylene) and an ethylene-vinyl alcohol layer was produced. The three-kind five-layer film was produced using a multilayer cast film molding machine (manufactured by Plastics Engineering Research Institute Co., Ltd.) at a set temperature of 200°C, and the film structure was a thermoplastic resin layer/hydrolyzate layer/ethylene-vinyl alcohol copolymer layer/hydrolyzate layer/thermoplastic resin layer, with thicknesses of 20 μm/10 μm/10 μm/10 μm/20 μm, respectively. The interlayer adhesive strength (peel strength) between the thermoplastic resin layer/hydrolyzate layer or between the hydrolyzate layer/ethylene-vinyl alcohol copolymer layer of the three-kind five-layer film was measured using a tensile tester (300 mm/min, T-type peel) after peeling a part of the interlayer at the end of the three-kind five-layer film, cutting out the film at intervals of 15 mm in the direction of resin flow (MD direction). If peeling between layers is difficult, it is possible to peel relatively easily by immersing the end of the three-kind five-layer film in a methanol solution for 1 to 2 minutes.

The measurement of interlayer adhesive strength was repeated 3 to 5 times for the same sample. Adhesive strength less than 2.5 N/15 mm was judged to be poor adhesion, and 2.5 N/15 mm or more was judged to be good adhesion. The thermoplastic resin (polyethylene) and EVOH used in film molding were as follows:
(1) Polyethylene: high-pressure low-density polyethylene with a melt mass flow rate of 2 g/10 min and a density of 923 kg/ ^m3 (manufactured by Tosoh Corporation, product name Petrothene 226)
(2) EVOH: ethylene-vinyl alcohol copolymer having a melt mass flow rate of 1.7 g/10 min and an ethylene content of 32 mol% (Kuraray Co., Ltd., product name EVAL F171B)

[Example 1]
45 parts by weight of ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation under the trade name Ultrathene 625) (hereinafter sometimes abbreviated as component (A-1)) having an MFR of 14 g/10 ^min , a density of 935 kg/m 3 and a vinyl acetate content of 5.4 mol % (15 wt %) as component (A),
45 parts by weight of ethylene-vinyl acetate copolymer having an MFR of 70 g/10 min, a density of 968 kg/m ³ and a vinyl acetate content of 19 mol % (42 wt %) (manufactured by Tosoh Corporation, trade name Ultrathene 760, hereinafter sometimes abbreviated as component (B-1)) as component (B);
10 parts by weight of the following component (C-1) as a compatibilizer (C),
[Component (C-1)]
A composition obtained by dry blending the following three types of ethylene-vinyl acetate copolymers at 3.3 parts by weight each: An ethylene-vinyl acetate copolymer having an MFR of 20 g/10 min, a density of 940 kg/m ³ and a vinyl acetate content of 20% by weight (manufactured by Tosoh Corporation, trade name Ultrathene 633).
Ethylene-vinyl acetate copolymer having an MFR of 18 g/10 min, a density of 949 kg/m ³ and a vinyl acetate content of 28% by weight (manufactured by Tosoh Corporation, product name Ultrathene 710)
Ethylene-vinyl acetate copolymer having an MFR of 30 g/10 min, a density of 954 kg/m ³ and a vinyl acetate content of 32% by weight (manufactured by Tosoh Corporation, product name Ultrathene 750)
0.02 parts by weight of an organic peroxide (manufactured by NOF Corp., trade name Perhexa 25B, hereinafter sometimes abbreviated as component (D-1)) as a crosslinking agent (D);
5 parts by weight of ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation under the trade name Ultrathene 530) (hereinafter sometimes abbreviated as component (E-1)) having an MFR of 75 g/10 ^min , a density of 923 kg/m 3 and a vinyl acetate content of 2.0 mol % (6 wt %) as component (E),
The mixture was dry-blended in a ratio of 1:1 and melt-kneaded in a twin-screw extruder at a set temperature of 190°C to obtain a melt-kneaded product containing the graft modified product in the form of pellets. The melt-kneaded product containing the graft modified product obtained was then subjected to a hydrolysis treatment in a 2% by weight solution of sodium hydroxide in methanol at 55°C to obtain a hydrolysate. The obtained hydrolysate was used to evaluate the film appearance and adhesion, and the results are shown in Table 1. In Table 1, the numerical values of each component represent parts by weight.

[Example 2]
A hydrolysate was obtained in the same manner as in Example 1, except that 5 parts by weight of a high-pressure low-density polyethylene having an MFR of 145 g/10 min and a density of 915 kg/ ^m3 (manufactured by Tosoh Corporation, product name Petrothene 353) (hereinafter sometimes abbreviated as component (E-2)) was added instead of component (E-1). The obtained hydrolysate was used to evaluate the film appearance and adhesion, and the results are shown in Table 1.

[Example 3]
A hydrolysate was obtained in the same manner as in Example 1, except that the amount of component (A-1) was changed to 70 parts by weight, and 20 parts by weight of an ethylene-vinyl acetate copolymer having an MFR of 5 g/10 min and a vinyl acetate content of 57 mol % (50 wt %) (manufactured by LANXESS KK, trade name Levapren 500; hereinafter sometimes abbreviated as component (B-2)) was added instead of component (B-1). The obtained hydrolysate was used to evaluate the film appearance and adhesion, and the results are shown in Table 1.

[Example 4]
A hydrolysate was obtained in the same manner as in Example 1, except that the amount of component (E-1) added was changed to 0.5 parts by weight. The obtained hydrolysate was used to evaluate the film appearance and adhesiveness, and the results are shown in Table 1.

[Example 5]
A hydrolysate was obtained in the same manner as in Example 1, except that the amount of component (E-1) added was changed to 30 parts by weight. The obtained hydrolysate was used to evaluate the film appearance and adhesion, and the results are shown in Table 1.

[Example 6]
A hydrolysate was obtained in the same manner as in Example 1, except that the amount of component (E-1) added was changed to 40 parts by weight. The obtained hydrolysate was used to evaluate the film appearance and adhesiveness, and the results are shown in Table 1.

[Comparative Example 1]
A hydrolysate was obtained in the same manner as in Example 1, except that 5 parts by weight of a high-pressure low-density polyethylene having an MFR of 8 g/10 min and a density of 919 kg/ ^m3 (manufactured by Tosoh Corporation, product name Petrothene 203) (hereinafter sometimes abbreviated as component (E-3)) was added instead of component (E-1). The obtained hydrolysate was used to evaluate the film appearance and adhesion to LDPE and EVOH, and the results are shown in Table 2. In Table 2, the numerical value of each component represents parts by weight. The obtained film had poor appearance.

[Comparative Example 2]
A hydrolysate was obtained in the same manner as in Example 1, except that component (C) was not added. The obtained hydrolysate was used to evaluate the film appearance and adhesion to LDPE and EVOH, and the results are shown in Table 2. The obtained film had poor adhesion to the EVOH layer.

[Comparative Example 3]
A hydrolysate was obtained in the same manner as in Example 1, except that component (D) was not added. The obtained hydrolysate was used to evaluate the film appearance and adhesion to LDPE and EVOH, and the results are shown in Table 2. The obtained film had poor adhesion to the EVOH layer.

[Comparative Example 4]
A hydrolysate was obtained in the same manner as in Example 1, except that component (E) was not added. The obtained hydrolysate was used to evaluate the film appearance and adhesion to LDPE and EVOH, and the results are shown in Table 2. The obtained film had poor appearance.

[Comparative Example 5]
A melt-kneaded product containing a graft modified product was obtained in the same manner as in Example 1, except that no hydrolysis treatment was performed. The obtained melt-kneaded product containing a graft modified product was used to evaluate the film appearance and adhesion to LDPE and EVOH, and the results are shown in Table 2. The obtained film had poor adhesion to the EVOH layer.

Claims (5)

A hydrolysate of a melt-kneaded product comprising: (A) a copolymer of ethylene and a vinyl ester having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less; (B) a copolymer of ethylene and a vinyl ester having a vinyl ester content of 17 mol% or more and 75 mol% or less; (C) a compatibilizer; (D) a crosslinking agent; and (E) a thermoplastic resin that satisfies the following requirements (1) and (2):
(1 ) At least one member selected from the group consisting of homopolymers of α-olefins having 2 to 12 carbon atoms, copolymers thereof, and copolymers of ethylene and vinyl esters having a vinyl ester content of 0.1 mol % or more and 3.4 mol % or less.
(2) The melt mass flow rate at 190° C. under a load of 2.16 kg is the melt mass flow rate of an ethylene-vinyl ester copolymer (A) having a vinyl ester content of 3.5 mol % or more and 7.0 mol % or less, and the melt mass flow rate of an ethylene-vinyl ester copolymer (A) having a vinyl ester content of 17 mol % or more and 7.0 mol % or less.
The melt mass flow rate is higher than that of the copolymer (B) of 5 mol % or less of ethylene and a vinyl ester. The compatibilizer (C) is a copolymer of ethylene and vinyl ester, and the vinyl ester content is 7.
The hydrolysate according to claim 1, comprising at least one copolymer of ethylene and vinyl ester in an amount of 5 mol % or more and 16 mol % or less. 3. The hydrolysate according to claim 1 or 2, further comprising 0.1 part by weight or more and 40 parts by weight or less of a thermoplastic resin (E) per 100 parts by weight in total of the ethylene and vinyl ester copolymer (A) having a vinyl ester content of 3.5 mol% or more and 7.0 mol% or less, the ethylene and vinyl ester copolymer (B) having a vinyl ester content of 17 mol% or more and 75 mol% or less, and the compatibilizer (C). A laminate comprising a layer made of the hydrolysate according to any one of claims 1 to 3. A layer containing a thermoplastic resin/a layer containing the hydrolysate according to any one of claims 1 to 3/
A laminate in which layers containing ethylene-vinyl alcohol copolymers are laminated in order.