JP2935889B2 - Laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polyolefin resin layer and a layer of a mixed composition comprising a saponified ethylene-vinyl acetate copolymer and the like.
Gas barrier properties, fragrance retention properties, comprising at least two layers,
And a laminate such as a film, a sheet, and a container having excellent oil resistance.

[Prior Art] A saponified ethylene-vinyl acetate copolymer is a thermoplastic resin that is mechanically good and has excellent gas barrier properties, fragrance retention properties, oil resistance, and the like. However, since it is hydrophilic, it has a disadvantage that the above properties are lost when it is exposed to a high-humidity atmosphere or comes into contact with a polar solvent such as water or alcohol.

Therefore, a laminate comprising at least two layers of a saponified ethylene-vinyl acetate copolymer and a hydrophobic polyolefin,
In particular, a laminated molded article comprising a saponified ethylene-vinyl acetate copolymer as an intermediate layer and an outer layer thereof protected by a polyolefin is desired. However, since the interface with the saponified ethylene-vinyl acetate copolymer polyolefin is insufficient for bonding, a laminate which can be used practically cannot be obtained.

Therefore, lamination of a saponified ethylene-vinyl acetate copolymer layer and a polyolefin layer is performed through an adhesive resin proposed in Japanese Patent Publication Nos. 48-126768 and 61-12782.

Further, there has also been proposed an example comprising a polyolefin layer, a saponified ethylene-vinyl acetate copolymer and a composition of a polyolefin without interposing an adhesive layer as described in JP-B-51-48512.

However, in this case, the adhesive strength between the polyolefin layer and the saponified ethylene-vinyl acetate copolymer / polyolefin composition layer is weak in a range where the gas barrier property is effective, and a laminate that can withstand practical use cannot be obtained. As long as the layer and the saponified ethylene-vinyl acetate copolymer and polyolefin composition layer can be laminated, the gas barrier effect is poor.

[Problems to be Solved by the Invention] As described above, in the prior art, a laminate with a polyolefin utilizing characteristics such as gas barrier properties and aroma retention properties of a saponified ethylene-vinyl acetate copolymer without an adhesive layer is used. There was a problem that could not be obtained.

In view of the above, the object of the present invention is to eliminate these drawbacks (problems), that is, the gas barrier property, which is a property of a saponified ethylene-vinyl acetate copolymer, without using an adhesive layer,
The purpose is to obtain a laminate with a polyolefin utilizing the scent retention and the like.

[Means and Actions for Solving the Problems] According to the present invention, these problems are as follows. The polyolefin resin layer and (a) 100 parts by weight of the polyolefin resin, (b) the copolymerization ratio of ethylene is 10% 10 to 80 parts by weight of a saponified ethylene-vinyl acetate copolymer obtained by saponifying at least 90% of an ethylene-vinyl acetate copolymer, and (c) a styrene-based thermoplastic elastomer. And 3 to 50 parts by weight of the maleic acid-modified resin, (d) ethylene and at least α, β-
5 to 40 parts by weight of an ethylene-based copolymer which is a copolymer with at least one monomer selected from the group consisting of unsaturated carboxylic acids, α, β-unsaturated dicarboxylic acids and anhydrides thereof And a layered product comprising a layer of the mixed composition.

 Hereinafter, the present invention will be described specifically.

A. Polyolefin resin Typical examples of the polyolefin resin used for producing the polyolefin resin layer of the present invention and the polyolefin resin used for the layer of the mixed composition include polypropylene. A random or block copolymer with propylene and / or ethylene and at most 12 other α-olefins (copolymerization ratio with α-olefin is at most 20% by weight) %), A homopolymer of ethylene, a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, and a homopolymer of an α-olefin having 4 to 6 carbon atoms.

Further, the present invention also includes a modified polyolefin obtained by graft-polymerizing a compound having at least one double bond (for example, an unsaturated carboxylic acid or a vinylsilane compound) to these olefin-based polymers. These polyolefin resins and modified polyolefins may be used alone or in combination of two or more.

In addition, two or more of these polyolefin-based resins and modified polyolefins may be used as a resin blend at an arbitrary ratio.

Further, an inorganic filler may be further added to these polyolefin resins, and the inorganic filler is generally widely used in the fields of synthetic resin and rubber. As these inorganic fillers, inorganic compounds which do not react with oxygen and water and which do not decompose during mixing and molding are preferably used. As inorganic fillers,
Aluminum, copper, iron, lead, nickel, magnesium,
Oxides of metals such as calcium, barium, zinc, zirconium, molybdenum, silicon, antimony, titanium,
Compounds such as hydrates (hydroxides), sulfates and carbonate silicates, double salts thereof, and mixtures thereof are roughly classified. Representative examples of the inorganic filler include the above-mentioned aluminum oxide (alumina), its hydrate, calcium hydroxide, magnesium oxide (magnesia), magnesium hydroxide, zinc oxide (zinc white), lead tin and lead white. Such as lead oxide, magnesium carbonate, calcium carbonate, basic magnesium carbonate, white carbon, asbestos,
Mica, talc, glass fiber, glass powder, glass beads, clay, diatomaceous earth, silica, wollastonite, iron oxide, antimony oxide, titanium oxide (titania), lithopone, pumice powder, aluminum sulfate (gypsum, etc.), silicate zirconium , Zirconium oxide, barium carbonate, dolomite, molybdenum disulfide and iron sand. Among these inorganic fillers, the powdery one has a diameter of 20μ.
m or less (preferably 10 μm or less). In the case of a fibrous material, the diameter is 1 to 500 μm (preferably 1 to 300 μm).
μm) and a length of 0.1 to 6 mm (preferably 0.1 to 5 mm) is desirable. Further, it is preferable that the flat plate has a diameter of 30 μm or less (preferably 10 μm or less). Among these inorganic fillers, those in the form of a flat plate (flakes) and those in the form of powder are particularly preferred.

Melt index of the olefin resin (JIS K7
Measured under condition 14 according to 210, hereinafter referred to as “MI (2)”] is usually 0.005 to 100 g / 10 min, and 0.01 to 80 g / 10 min.
Minutes, and particularly preferably 0.02 to 50 g / 10 minutes. If a polyolefin-based resin having an MI (2) of less than 0.005 g / 10 minutes is used, extrusion molding cannot be performed due to poor fluidity, and a sheet layer cannot be formed. 100g / 10
If a polyolefin-based resin is used in excess of this amount, a good product with a large drawdown cannot be obtained when producing these coextruded sheets.

In addition, when blending an inorganic filler, the blending ratio of the inorganic filler in the total amount of the polyolefin resin and the inorganic filler is generally at most 80% by weight and 70% by weight.
The following is preferable, and especially 60% by weight or less is suitable. 80% by weight of inorganic filler in the total amount
If it exceeds 3, it is difficult to form a sheet by press forming, and a good sheet cannot be obtained.

B. Saponified ethylene-vinyl acetate copolymer Further, the saponified ethylene-vinyl acetate copolymer used in the mixed composition layer in the present invention has an ethylene content of 10%.
エ チ レ ン 60 mol% of an ethylene-vinyl acetate copolymer is saponified at least 90 mol% or more.

Further, those having a molecular weight that can be formed into a film and a sheet are desirable, and a melt index [measured at a temperature of 210 ° C. and a load of 2.16 kg according to JIS K-7210 below “MI
(2) ") is usually 0.1 to 50 g / 10 minutes, and 0.1 to 20 g
g / 10 minutes is desirable.

When a saponified ethylene-vinyl acetate copolymer having an MI (2) of less than 0.1 / 10 minutes is used, when a laminate is produced, the flowability of the resin is so low that the resin does not flow and a good laminate cannot be obtained. On the other hand, when a saponified ethylene-vinyl acetate copolymer exceeding 20 g / 10 is used, when a laminate is produced, the fluidity of the resin is too high to obtain a good laminate.

C. Styrene-based thermoplastic elastomer The styrene-based thermoplastic elastomer used in the mixed composition in the present invention is styrene and hydrogenated butadiene copolymer or styrene and hydrogenated isoprene copolymer, and styrene and hydrogenated butadiene copolymer. Further, those obtained by adding maleic anhydride to a styrene-hydrogenated isoprene copolymer are also very good.

Styrene and hydrogenated butadiene copolymer or styrene and hydrogenated isoprene copolymer consists of styrene polymer block and hydrogenated butadiene or hydrogenated isoprene block,
Examples of the styrene-based polymer include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, vinylnaphthalene, and a mixture thereof.

In addition, styrene and hydrogenated butadiene copolymer or styrene and hydrogenated isoprene copolymer used in the present invention, and styrene and hydrogenated butadiene copolymer or styrene and hydrogenated isoprene copolymer with maleic anhydride added Has a styrene content of 10 to 40 wt% and a solution viscosity (25 wt%
Toluene solution at 25 ° C) having characteristics of 100 to 50,000 CCPS. If the solution viscosity is less than 100 CPS, the fluidity is high and the compatibility of the mixed composition is poor, so that the gas barrier effect and the adhesive strength after the polyolefin are not exhibited.

On the other hand, if the solution viscosity exceeds 50,000 CPS, the fluidity is poor, the compatibility in the mixed composition is poor, and the gas barrier effect and the adhesive strength with the polyolefin resin are not exhibited.

These are also commercially available and can be made by methods well known to those skilled in the art.

D. Ethylene copolymer Melt index of the ethylene copolymer used in the mixed composition layer in the present invention (according to JIS K7210,
Measured under condition 4, hereinafter referred to as “MI (1)”] is usually 1.0
1,0001,000 g / 10 min, preferably 1.0-800 g / 10 min, particularly preferably 2.0-700 g / 10 min.

When an ethylene copolymer having an MI (1) of less than 1.0 g / 10 minutes is used, the compatibility in the mixed composition layer is poor, the adhesion to the polyolefin resin phase is poor, and a laminate that can withstand practical use cannot be obtained. .

When an ethylene copolymer having an MI (1) of more than 1,000 g / 10 minutes is used, similarly, the compatibility in the mixed composition layer is poor, the adhesion to the polyolefin resin phase is poor, and the laminate can withstand practical use. Can not be obtained.

Further, the ethylene copolymer used in the mixed composition layer in the present invention may be an ethylene copolymer composed of ethylene and a comonomer (1) whose representative examples are described below,
An ethylene-based multi-component copolymer composed of ethylene, a comonomer (1) and a comonomer (2) whose representative examples are described below may be used.

Comonomer (1) is an α, β-unsaturated monocarboxylic acid,
It is at least one comonomer selected from α, β-unsaturated dicarboxylic acids and their anhydrides.

Among the comonomers (1), the α, β-unsaturated monocarboxylic acid generally has 3 to 20 carbon atoms, preferably 3 to 15 carbon atoms, and more preferably 3 to 10 carbon atoms.
Representative examples of suitable α, β-unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, monoalkyl malates, monoalkyl fumarate, and the like. The α, β-unsaturated dicarboxylic acid usually has 4 to 30 carbon atoms, preferably 4 to 20 carbon atoms, and more preferably 4 to 20 carbon atoms.
Sixteen are preferred. Representative examples of suitable α, β-unsaturated dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid, 3,6-endomethylene-1,2,3,6
-Tetrahydro-cis-phthalic acid (nadic acid).

As the comonomer (1), anhydrides of these α, β-unsaturated dicarboxylic acids can also be preferably used.

Further, comonomer (2) is selected from vinyl esters and unsaturated carboxylic esters.

Among the comonomers (2), the vinyl ester generally has 4 to 25 carbon atoms, preferably 4 to 20 carbon atoms,
Particularly, those having 4 to 16 pieces are preferable. Representative examples of suitable vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, and the like.

The unsaturated carboxylic acid ester usually has 4 to 40 carbon atoms, preferably 4 to 30 carbon atoms, and particularly preferably 4 to 20 carbon atoms. Representative examples of suitable unsaturated carboxylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate and the like. Further, as the unsaturated carboxylic acid ester, alkoxyalkyl (meth) acrylate is also exemplified as the comonomer (2). The alkoxyalkyl (meth) acrylate preferably has an alkyl group having 1 to 8 (preferably 1 to 4) carbon atoms. Further, it is desirable that the alkoxy group has 1 to 8 (preferably 1 to 4) carbon atoms. Representative examples of suitable alkoxyalkyl (meth) acrylates include methoxymer (meth) acrylate and methoxyethyl (meth) acrylate.
Acrylates, ethoxyethyl (meth) acrylate and butoxyethyl (meth) acrylate are mentioned.

E. Mixing ratio of mixed composition and its production The mixing ratio of each resin used in the mixed composition layer of the present invention is 100 to 100 parts by weight of polyolefin resin, ethylene-vinyl acetate copolymer saponified 10 to 80. Parts by weight, 3 to 50 parts by weight of a styrene-based thermoplastic elastomer, 5 to 40 parts by weight of an ethylene-based copolymer, and the proportion of the polyolefin-based resin in the mixed composition is 20 to 80% by weight. 30
~ 70% by weight.

The proportion of the polyolefin resin in the mixed composition is
If the amount is less than 20% by weight, a laminate which has poor adhesion to the polyolefin layer and cannot be used practically is not obtained. On the other hand, if it exceeds 80% by weight, a product exhibiting gas barrier properties and fragrance retention properties cannot be obtained. The ratio of the saponified ethylene-vinyl acetate copolymer in the mixture is 10 to 80 parts by weight, preferably 20 to 70 parts by weight, based on 100 parts by weight of the polyolefin resin.
At the end of 20 parts by weight, gas barrier properties and fragrance retention properties are not exhibited, and when it exceeds 80 parts by weight, adhesion to the polyolefin layer is weak, and a laminate that can withstand practical use cannot be obtained.

The styrene thermoplastic elastomer is used in an amount of 3 to 50 parts by weight, preferably 5 to 40 parts by weight, based on 100 parts by weight of the polyolefin resin. If the styrene-based thermoplastic elastomer is less than 3 parts by weight, the dispersion of the saponified ethylene-vinyl acetate copolymer in the mixed composition is poor, and the gas barrier property does not exhibit aroma retention. On the other hand, if it exceeds 50 parts by weight, the polyolefin layer and Is poor in adhesiveness, and a laminated body that can withstand practical use cannot be obtained.

Further, the proportion of the ethylene copolymer resin in the mixed composition is 5 to 4 parts by weight per 100 parts by weight of the polyolefin resin.
0 parts by weight, preferably 8 to 30 parts by weight. If the proportion of the ethylene copolymer resin is less than 5 parts by weight, the dispersion of the saponified ethylene-vinyl acetate copolymer in the mixed composition is poor and the gas barrier is poor. Fragrance and fragrance are not exhibited, while 40
When the amount exceeds the weight part, gas barrier properties and fragrance retention properties are not exhibited.

In the production of the mixed composition of the present invention, each resin constituting the mixed composition may be mixed with a mixing mixer such as a tumbler, a Henschel mixer, a super mixer, or the like, and may be mixed with a mixing mixer of a raw material supply system before the extruder. It can also be produced by melt-mixing each resin constituting the mixed composition using a kneader generally used in the field of synthetic resins such as a screw type extruder, a Banbury mixer and a kneader.

F. Production of Laminate The laminate of the present invention is a laminate of at least two layers composed of the polyolefin layer and the mixed composition layer described above.

A laminate of these layers can be obtained by a generally known coextrusion method, for example, a film, a sheet by coextrusion T-die molding, a film, a sheet by cocircular die molding, a container, a bottle, a co-injection by coextrusion hollow molding. Various types of containers and the like can be obtained by molding.

The extrusion temperature of the coextrusion molding for obtaining the laminate of the present invention is generally 100 to 350 ° C, preferably 150 to 330 ° C, particularly
180-300 ° C is preferred.

Further, the thickness of each layer of the laminate of the present invention, the mixed composition layer constituting the intermediate layer is 20 ~ 3000μ, preferably 50 ~ 2000μ
It is.

If the thickness of the mixed composition layer constituting the intermediate layer is less than 20 μm, the gas barrier effect is poor. On the other hand, if it exceeds 300 μm, molding is difficult and the product has poor practicality.

Furthermore, one side of the polyolefin layer that forms the inner and outer layers is 50 to
3000μ, preferably 10-1000μ.

If one side of the polyolefin layer constituting the inner and outer layers is less than 5μ, the permeation of water vapor is large and the barrier effect of the mixed composition layer cannot be maintained for a long time, whereas if it exceeds 300μ, molding is difficult, resulting in poor practicality. .

Examples and Comparative Examples Hereinafter, the present invention will be described in more detail with reference to Examples.

In the examples and comparative examples, the oxygen permeability of each sample was measured using an oxygen permeation measuring apparatus “Modern Control (USA) Model OX-RTAN10 / 50” at a measurement temperature of 23 ° C. and a relative humidity of 6
It was measured under the condition of 0%.

The adhesive strength (stripping strength) is 15% of the obtained laminate.
Sampling a sample with a width of 10 mm
A peel test was performed in the direction of 180 ° / min, and the adhesive strength was determined.

Types of polyolefin resin, ethylene copolymer resin, styrene thermoplastic elastomer resin, maleic acid modified resin of styrene thermoplastic elastomer resin, saponified ethylene vinyl acetate copolymer used in Examples and Comparative Examples And physical properties are shown below.

[(A) Polyolefin-based resin] As a polyolefin-based resin, an ethylene-propylene block copolymer having an MI (1) of 0.5 / 10 minutes and an ethylene copolymerization ratio of 18% by weight [hereinafter referred to as “PP (A) ) "
MI (1) is 2.0 / 10 minutes, propylene homopolymer [hereinafter referred to as “PP (B)”] MI (3) is 0.2 / 10 minutes, and the density is 0.955 g / cm ³ . An ethylene homopolymer [hereinafter referred to as “PE (1)”] Ethylene having an MI (3) of 1.0 / 10 minutes, a density of 0.928 g / cm ³ , and a copolymerization ratio of butene-1 of 20 wt% -Butene-1 copolymer [hereinafter referred to as "PE (2)"] [(B) Saponified ethylene-vinyl acetate copolymer] As a saponified ethylene-vinyl acetate copolymer, the copolymerization ratio of ethylene is 25. Mol%, saponification obtained by saponifying an ethylene-vinyl acetate copolymer [a degree of saponification of 99%, MI (2) of 5.0 g / 10 min.
(1) "] Further, as a saponified ethylene-vinyl acetate copolymer, a saponified product obtained by saponifying an ethylene-vinyl acetate copolymer having a copolymerization ratio of ethylene of 38 mol% is obtained. 99%, MI (2) 3.0g / 10min, hereinafter referred to as “EVOH (2)”] [(C) Styrene-based thermoplastic elastomer] KRATON (trade name, manufactured by Shell Chemical Co., Ltd.) as a styrene-based thermoplastic elastomer FG1901X (styrene content 28
wt%, maleic anhydride addition rate 2wt%, solution viscosity 6,000CP
S, hereinafter referred to as "SEBS-M"] Kuraray Co., Ltd. product name Septon 1001 [styrene content 35 wt%, solution viscosity 6,100 CPS, hereinafter referred to as "SEBS"] [(D) Ethylene copolymer As an ethylene-based copolymer, an ethylene-acrylic acid-maleic anhydride terpolymer having MI (1) of 500 g / 10 minutes [copolymerization ratio of acrylic acid: 24.5 wt%, copolymerization ratio of maleic anhydride] 4.4 wt%, hereinafter referred to as "EEA"] Ethylene-methyl methacrylate-maleic anhydride terpolymer having MI (1) of 7.0 g / 10 min [copolymerization ratio of methyl methacrylate 2.9 wt%, maleic anhydride Examples 1 to 7 Comparative Examples 1 to 7 The mixed compositions constituting the mixed composition layer were determined by the mixing ratio of each resin shown in Table 1 below. Created in the way.

Using an extruder with L / D = 28, diameter 65mmΦ, extruding temperature 2
The temperature was set at 20 ° C., and kneading and mixing were performed to prepare pellets for a mixed composition layer.

Next, two-type, three-layer multilayer sheet manufacturing equipment (Toshiba Machine Co., Ltd.)
Co-extrusion molding using a feed block type 40 mmφ extruder (manufactured by Sharp Corporation) at an extrusion temperature of 230 ° C. so that the intermediate layer becomes the mixed composition layer shown in Table 1 and the inner and outer layers become the polyolefin resin layer. A laminated sheet having the layer configuration shown in Table 2 was prepared.

Table 2 shows the results of measuring the oxygen gas permeability of the obtained laminated sheet and the adhesive strength between the polyolefin layer and the mixed composition layer of the laminated sheet.

In the same manner as in Example 1, pellets of the mixed composition having a resin composition out of the range of the present invention shown in Comparative Examples of Table 1 were prepared, and the intermediate layer was formed into a first layer by a two-type and three-layer multilayer sheet manufacturing apparatus. The mixed composition layer and the inner and outer layers shown in the table were co-extruded and formed into a polyolefin resin layer to prepare a laminated sheet.

The results of measuring the oxygen gas permeability of the obtained laminated sheet and the adhesive strength between the polyolefin layer and the mixed composition layer of the laminated sheet are shown in Table 2 as in Example 1.

The results obtained in this way are shown secondly as Examples and Comparative Examples. However, the laminate of the present invention is superior in oxygen barrier properties as compared with Comparative Examples, and the laminate of the mixed composition layer and the polyolefin layer has It is clear that the adhesive strength is excellent.

Examples 8 to 11 Comparative Examples 6 to 10 In the same manner as in Example 1, mixed compositions of the respective resin compositions shown in Table 3 were prepared.

Next, using a two-type three-layer co-extrusion blow molding machine (two 40 mmφ extruders manufactured by Nippon Steel Corporation) so that the mixed composition becomes the intermediate layer and the polyolefin resin layer becomes the inner and outer layers, The die temperature was set to 200 ° C., and a cylindrical multilayer bottle having a capacity of 500 cc was prepared.

Obtained, oxygen permeability of the cylindrical multilayer bottle of 500 cc capacity, and measured by cutting the body of the bottle, the adhesive strength between the polyolefin resin layer and the mixed composition layer, and the polyolefin resin layer and the mixed composition layer Table 4 shows the composition ratio of the layer thickness.

In the same manner as in Example 1, pellets of a mixed composition having a resin composition outside the scope of the present invention shown in Comparative Examples in Table 3 were prepared, and a two-type, three-layer co-extrusion blow molding machine was formed in the same manner as in Example. Was used to make a cylindrical multilayer bottle with a capacity of 500 cc.

Obtained, oxygen permeability of the cylindrical multilayer bottle of 500 cc capacity, and measured by cutting the body of the bottle, the adhesive strength between the polyolefin resin layer and the mixed composition layer, and the polyolefin resin layer and the mixed composition layer Table 4 shows the composition ratio of layer thickness as a comparative example.

The results obtained in this way are shown in Table 4. It is clear that the laminate of the present invention has excellent oxygen barrier properties and excellent adhesive strength between the mixed composition layer and the polyolefin layer. is there.

[Effects of the Invention] The laminate of the present invention is formed by coextrusion T-die molding, coextrusion circular die molding, coextrusion hollow molding, coextrusion injection molding, etc., into films, sheets, pipes, and various containers such as balls. It is formed into a tray-shaped, bottle-shaped, or tank-shaped container, and is used in a wide range of fields such as general food packaging, packaging of chemicals and pharmaceuticals, and general industrial use.

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Claims (1)

(57) [Claims] 1. A polyolefin resin layer, wherein the copolymerization ratio of (b) ethylene is 10 to 65 mol% with respect to 100 parts by weight of the polyolefin resin (a), and at least ethylene-vinyl acetate copolymer is used. 10 to 80 parts by weight of a saponified ethylene-vinyl acetate copolymer obtained by saponifying at least 90%, (c) 3 to 50 parts by weight of a styrene-based thermoplastic elastomer and its maleic acid-modified resin, (d)
Ethylene and at least an α, β-unsaturated carboxylic acid, α,
5 to 40 parts by weight of an ethylene copolymer which is a copolymer with at least one monomer selected from the group consisting of β-unsaturated dicarboxylic acids and anhydrides thereof, and A laminate comprising: