JP2023146408A - laminate - Google Patents

Abstract

To provide a laminate which is excellent in gas barrier property, adhesion, and secondary workability.SOLUTION: A laminate includes at least a base material layer, and a layer (C), a layer (B) and a layer (A) that are adjacent to each other from the base material layer side, wherein the base material layer is composed of a composite base material (S) satisfying (i) to (ii), the layer (A) is composed of polyolefin (a), the layer (B) is composed of an adhesive resin (b), and the layer (C) is composed of an ethylene-vinyl alcohol copolymer (c) satisfying (iii). (i) The composite base material contains a cellulose-based material and a thermoplastic resin, (ii) the percentage content of the cellulose-based material is 25 wt.% or more and 75 wt.% or less, and (iii) the ethylene content C2 is 50 mol% or less.SELECTED DRAWING: None

Description

The present invention relates to a laminate.

Ethylene-vinyl alcohol copolymer (hereinafter referred to as "ethylene-vinyl alcohol copolymer"), which has excellent gas barrier properties, fragrance retention properties, and solvent resistance, is used as a packaging material made of thermoplastic resin for foods, beverages, pharmaceuticals, etc., with the aim of preventing the contents from deteriorating. EVOH (sometimes abbreviated as EVOH) is used for various purposes, and laminates are produced by coextruding polyethylene resin, acid-modified polyolefin, and EVOH onto a paper base material such as paperboard (for example, see Patent Document 1). ing.

However, when a laminate using such a paper base material is formed into a box by heat sealing, oxygen and the like pass through the sealed portion, resulting in poor gas barrier properties as a container. On the other hand, even if vacuum forming, drawing forming, etc., in which no seal portion occurs, a laminate using a paper base material cannot be formed because it does not have secondary processability.

Against this background, there has been a desire for a laminate with excellent gas barrier properties, adhesive properties, and secondary processability.

Japanese Patent Application Publication No. 1992-234645

The present invention was made in view of the above situation, and an object of the present invention is to provide a laminate exhibiting excellent gas barrier properties, adhesive properties, and secondary processability.

As a result of intensive studies to solve the above problems, the present inventors discovered that a specific laminate exhibits excellent gas barrier properties, adhesive properties, and secondary processability, and completed the present invention.

Each aspect of the present invention is [1] to [12] shown below.
[1] A laminate including at least a base material layer and (C) layer/(B) layer/(A) layer adjacent to each other from the base material layer side, wherein the base material layer includes (i) to (ii). Composite base material (S) that satisfies (iii), the (A) layer is a polyolefin (a), the (B) layer is an adhesive resin (b), and the (C) layer is an ethylene-vinyl alcohol copolymer that satisfies (iii). A laminate consisting of c).

(i) Contains cellulose material and thermoplastic resin (ii) Content of cellulose material is 25% by weight or more and 75% by weight or less (iii) Ethylene content _C2 is 50 mol% or less [2] Composite base material (S) The laminate according to [1] above, wherein the content of the cellulosic material contained in the laminate is 35% by weight or more and 65% by weight or less.
[3] The laminate according to any one of [1] to [2] above, wherein the cellulose material contained in the composite base material (S) is a pulverized product of pulp fibers and/or paper.
[4] The laminate according to [3] above, wherein the composite substrate (S) is a sheet made of a melt-kneaded product of a pulverized paper product and a thermoplastic resin containing polyolefin and/or polyester.
[5] The laminate according to [3] above, wherein the composite base material (S) is a mixed paper of pulp fibers, polyolefin fibers, and/or polyester fibers.
[6] The laminate according to any one of [1] to [5] above, wherein the polyolefin (a) satisfies (iv) to (vi).

(iv) Melt mass flow rate (MFR _PO ) measured according to JIS K6922-1 (1997) is 1.0 g/10 minutes or more and 10.0 g/10 minutes or less (v) Measured at a temperature of 190°C and a withdrawal speed of 10 m/min. The melt tension (MS _PO ) is 3 mN or more and 50 mN or less (vi) Product of MFR _PO (g/10 min) and MS _PO (mN) MFR _PO × MS _PO is 70 or more and 250 or less [7] Polyolefin (a) is ethylene - The laminate according to any one of [1] to [6] above, which contains an α-olefin copolymer and/or a high-pressure low-density polyethylene.
[8] The laminate according to any one of [1] to [7] above, wherein the adhesive resin (b) contains a maleic anhydride-modified polyolefin.
[9 _{] The} above ^[ [ 1] to [8].

D _EVOH <-4.265×C ₂ +1325 (1)
[10] Further includes (E) layer/(D) layer between the base material layer and the (C) layer, the (E) layer is adjacent to the base material layer, and the (D) layer is adjacent to the (C) layer. The laminate according to any one of [1] to [9] above, wherein the (E) layer is made of polyethylene (e) and the (D) layer is made of adhesive resin (d), which are adjacent to each other.
[11] (C) layer/(B) layer/(A) layer, or (E) layer/(D) layer/(C) layer/(B) layer/(A) layer simultaneously by coextrusion lamination molding The method for producing a laminate according to any one of [1 to 10] above.
[12] A method for manufacturing a container, comprising molding the laminate according to any one of [1] to [10] above by secondary processing.

According to the present invention, it is possible to provide a laminate with excellent gas barrier properties, adhesive properties, and secondary processability.

Hereinafter, a laminate that is one embodiment of the present invention will be described in detail.

The present invention is a laminate including at least a base material layer and (C) layer/(B) layer/(A) layer adjacent to each other from the base material layer side, wherein the base material layer is (i) to (ii). The composite base material (S) satisfies (iii), the (A) layer is a polyolefin (a), the (B) layer is an adhesive resin (b), and the (C) layer is an ethylene-vinyl alcohol copolymer (c) that satisfies (iii). ), it relates to a laminate consisting of

(i) Contains cellulose material and thermoplastic resin (ii) Content of cellulose material is 25% by weight or more and 75% by weight or less (iii) Ethylene content _C2 is 50 mol% or less (A) Layer is made of polyolefin (a) Consisted of.

The polyolefin (a) is not particularly limited, and includes homopolymers of α-olefins having 2 to 12 carbon atoms such as ethylene, propylene, and 1-butene, or copolymers thereof, ethylene and vinyl esters, and/or acrylic acid. Examples include copolymers with esters. More specifically, ethylene homopolymers such as high-pressure low-density polyethylene and high-density polyethylene, ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, Ethylene/α-olefin copolymers such as ethylene/4-methyl-1-pentene copolymers, ethylene/vinyl acetate copolymers, ethylene/acrylic ester copolymers, ethylene/methacrylic ester copolymers, etc. Examples include ethylene polymers, propylene homopolymers, propylene/ethylene copolymers, propylene/1-butene copolymers, poly-1-butene, poly-1-hexene, poly-4-methyl-1-pentene, and the like. The polyolefin (a) may be used alone or in a composition of two or more. Among these, ethylene homopolymers, ethylene/α-olefin copolymers, and ethylene-based copolymers are preferred because of their excellent ease of opening, and high-pressure low-density polyethylene and ethylene/α-olefin copolymers are more preferred. From the viewpoint of moldability, the ethylene/α-olefin copolymer preferably contains high-pressure low density polyethylene.

A high-pressure method for producing low-density polyethylene can be exemplified by high-pressure radical polymerization, and such resins can be conveniently selected from commercially available products, such as those commercially available from Tosoh Corporation under the trade name Petrocene. ing.

Ethylene/α-olefin copolymers can be obtained by copolymerizing ethylene and α-olefins using high, medium, and low pressure ionic polymerization methods using Ziegler-Natta catalysts, Phillips catalysts, or metallocene catalysts.

The α-olefins constituting the ethylene/α-olefin copolymer include propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, and 1-heptene. , 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, etc., and one or more of these may be used. Among these α-olefins, α-olefins having 5 or less carbon atoms are preferred because of their excellent ease of opening.

Such an ethylene/α-olefin copolymer can be conveniently selected from commercially available products. For example, they are commercially available from Tosoh Corporation under the trade names of Nipolon-L, Nipolon-Z, and Lumitac.

The melt mass flow rate (hereinafter abbreviated as "MFR _PO ") measured according to JIS K6922-1 (1997) of polyolefin (a) is based on the coextrusion lamination processability with adhesive resin and ethylene/vinyl alcohol copolymer ( (migration), the range is preferably 1.0 g/10 minutes or more and 10.0 g/10 minutes or less, more preferably 1.0 g/10 minutes or more and 6.0 g/10 minutes or less, and most preferably 3.0 g/10 minutes. /10 minutes or more and 5.0g/10 minutes or less.

In addition, the melt tension (hereinafter abbreviated as "MS _PO ") of polyolefin (a) measured at a temperature of 190° C. and a drawing speed of 10 m/min is preferably in the range of 3 mN or more and 50 mN or less, more preferably is in the range of 10 mN or more and 45 mN or less, most preferably 15 mN or more and 40 mN or less.

The MS _PO in the present invention has an extrusion speed of 10 m under the conditions that a capillary viscometer with a barrel diameter of 9.55 mm is equipped with a die having a length of 8 mm, a diameter of 2.095 mm, an inlet angle of 90°, and a heat retention chamber. /min, a take-up speed of 10 m/min, and a set temperature of 190°C.

The product of MFR _PO (g/10 min) and MS _PO (mN) of polyolefin (a), MFR _PO ×MS _PO , is preferably in the range of 70 or more and 250 or less, more preferably 70 or more and 200 or less. It is in the following range, most preferably in the range of 90 or more and 160 or less. If MFR _PO ×MS _PO is less than 70, lamination workability is poor, which is undesirable, and if it exceeds 250, stretchability is poor, which is not preferred. Such MFR _PO ×MS _PO is a value that correlates with the ratio of melt elasticity to melt viscosity of polyethylene, that is, the nonlinearity during melt deformation of polyethylene.

The density (hereinafter simply referred to as density) of polyolefin (a) measured according to JIS K6922-1 (1997) is not particularly limited, but is preferably in the range of 910 to 930 kg/m ³ because it has excellent moldability. The preferred range is 914 to 925 kg/m ³ .

Other thermoplastic resins may be blended with the polyolefin (a) as long as this objective is achieved.

When mixing a thermoplastic resin with polyolefin (a), a pellet mixture in which polyolefin pellets and thermoplastic resin pellets are mixed in a solid state may be used, but a single screw extruder, twin screw extruder, kneader, A mixture melt-kneaded using Banbury or the like is preferable because a product with stable quality can be obtained. When using a melt-kneading device, the melting temperature is preferably from the melting point of the polyolefin to about 300°C.

In addition, additives commonly used in polyolefin resins, such as antioxidants, light stabilizers, antistatic agents, lubricants, and antiblocking agents, may be added to the polyolefin (a) as necessary to impede the purpose of the present invention. It may be added within the range.

In the laminate of the present invention, the (B) layer is composed of the adhesive resin (b).

The adhesive resin (b) is not particularly limited as long as the present purpose is achieved, and examples thereof include known resins used in molding applications. Examples of such adhesive resins include acid-modified polyolefins modified with unsaturated carboxylic acids or their anhydrides such as maleic acid and maleic anhydride, boronic acids, etc., ethylene, propylene, 1-butene, etc. such as polyamide-grafted polyolefins, etc. homopolymers of α-olefins having 2 to 12 carbon atoms or modified products of copolymers thereof, ethylene and unsaturated carboxylic esters such as vinyl esters and/or acrylic esters, methacrylic esters, and glycidyl methacrylate. Examples include copolymers of ethylene and vinyl ester copolymers, saponified ethylene/vinyl ester copolymers, copolymers of ethylene and unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and ionomers thereof. Among these, from the viewpoint of adhesiveness and cost, it is preferable to contain at least maleic anhydride-modified polyolefin, and more preferably to contain maleic anhydride-modified polyethylene (hereinafter abbreviated as MAH-PE).

Such maleic anhydride-modified polyolefin is not particularly limited, and may be a copolymer of an olefin component and maleic anhydride, or a polyolefin graft-modified with maleic anhydride. Furthermore, there are no particular limitations on the method for producing such a resin.

The olefin component constituting the maleic anhydride-modified polyolefin is not particularly limited, and includes vinyl esters such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, vinyl acetate and vinyl benzoate, acrylic acid, methacrylic acid, and acrylic. Examples include acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate, ethyl methacrylate, and glycidyl methacrylate, and unsaturated carboxylic acids such as acrylic acid and methacrylic acid. It may be used in combination of more than one species.

The maleic anhydride content of such maleic anhydride-modified polyolefin is preferably 0.10 to 1.2% by weight, more preferably 0.40 to 1.0% by weight, since it provides excellent adhesiveness and film appearance. , most preferably 0.40 to 0.80% by weight.

Such a resin can be conveniently selected from commercially available products. For example, a copolymer of an olefin component and maleic anhydride is available from SK Geo Centric Japan (under the trade name Amplify) from Dow Chemical Japan Co., Ltd. It is commercially available under the trade names Rotader, Bondine, and OREVACT from Co., Ltd., respectively. In addition, as polyolefins graft-modified with maleic anhydride, for example, Mitsui Chemicals Co., Ltd. sells them under the trade name Admer, Mitsubishi Chemical Co., Ltd. sells them under the trade name Modic, and Dow Chemical Japan Co., Ltd. sells them under the trade name Fusabond. These are commercially available from SK Geo Centric Japan Co., Ltd. under the trade name OREVAC G, and from Addivant Japan LLC under the trade name Polybond.

From the viewpoints of adhesiveness and film appearance, the adhesive resin (b) is preferably a polyolefin composition containing at least a polyolefin and a maleic anhydride-modified polyolefin.

From the viewpoint of adhesiveness and film appearance, the polyolefin composition contains 50 to 90 parts by weight of polyolefin and 10 to 50 parts by weight of maleic anhydride-modified polyolefin (total of polyolefin and maleic anhydride-modified polyolefin is 100 parts by weight). More preferably, it contains 65 to 85 parts by weight of polyolefin and 15 to 35 parts by weight of maleic anhydride-modified polyolefin (the total of polyolefin and maleic anhydride-modified polyolefin is 100 parts by weight).

The polyolefin is not particularly limited, and includes homopolymers of α-olefins having 2 to 12 carbon atoms such as ethylene, propylene, and 1-butene, copolymers thereof, and combinations of ethylene and vinyl esters and/or acrylic esters. Examples include copolymers.

For example, ethylene homopolymers such as high-pressure low-density polyethylene and high-density polyethylene, ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, ethylene/4- Ethylene polymers such as methyl-1-pentene copolymer, ethylene/vinyl acetate copolymer, ethylene/acrylic acid ester copolymer, ethylene/methacrylic acid ester copolymer, propylene homopolymer, propylene/ethylene copolymer, etc. Polymers, propylene/1-butene copolymer, poly-1-butene, poly-1-hexene, poly-4-methyl-1-pentene, and the like. The polyolefins may be used alone or in a composition of two or more. Among them, from the viewpoint of moldability, at least one of the group consisting of high-pressure low density polyethylene, ethylene/vinyl acetate copolymer, high density polyethylene, ethylene/1-butene copolymer, ethylene/1-hexene copolymer, and polypropylene is used. One type is preferable, and these compositions are most preferable because they have excellent moldability.

A high-pressure method for producing low-density polyethylene can be exemplified by high-pressure radical polymerization, and such resins can be conveniently selected from commercially available products, such as those commercially available from Tosoh Corporation under the trade name Petrocene. ing. The manufacturing method of high-density polyethylene, ethylene/1-butene copolymer, and ethylene/1-hexene copolymer is not particularly limited, but high- and medium-density polyethylene using Ziegler-Natta catalyst, Phillips catalyst, and metallocene catalyst are used. - Low-pressure ionic polymerization can be exemplified, and such resins can be conveniently selected from commercially available products. For example, they are commercially available from Tosoh Corporation under the trade names of Nipolon Hard, Nipolon-L, Nipolon-Z, and Lumitac.

The method for producing the ethylene/vinyl acetate copolymer is not particularly limited, but includes known production methods such as high-pressure radical polymerization, solution polymerization, and latex polymerization, and such resins may be conveniently selected from commercially available products. It is commercially available as an ethylene/vinyl acetate copolymer from Tosoh Corporation under the trade name Ultrasen.

The method of mixing such a polyolefin composition is not particularly limited, and a pellet mixture in which polyolefin pellets and maleic anhydride-modified polyolefin pellets are mixed in a solid state may be used, but from the viewpoint of quality stability, melt kneading is preferred. A mixture of these is preferred.

Such a melt-kneading method is not particularly limited as long as it is a melt-kneading device that can uniformly disperse each component, and it can be produced using a commonly used resin mixing device. Examples include melt-kneading devices such as a single-screw extruder, a multi-screw extruder, a Banbury mixer, a pressure kneader, a rotary roll, and a laboplast mill. The melting temperature is preferably from the melting point of the polyolefin to about 260°C.

The melt mass flow rate (hereinafter abbreviated as "MFR _ADD ") measured according to JIS K6922-1 (1997) of adhesive resin (b) is based on the coextrusion lamination processability (hereinafter referred to as "MFR ADD") with polyolefin and ethylene/vinyl alcohol copolymer. (migration), the range is preferably 1.0 g/10 minutes or more and 10.0 g/10 minutes or less, more preferably 1.0 g/10 minutes or more and 6.0 g/10 minutes or less, and most preferably 3.0 g/10 minutes. /10 minutes or more and 5.0g/10 minutes or less.

Other thermoplastic resins may be blended with the adhesive resin (b) as long as this objective is achieved. When a thermoplastic resin is mixed with the adhesive resin (b), it may be a pellet mixture in which saponified ethylene/vinyl ester copolymer pellets and thermoplastic resin pellets are mixed in a solid state. A mixture melt-kneaded using an extruder, twin-screw extruder, kneader, Banbury, etc. is preferable because a product with stable quality can be obtained. When using a melt-kneading device, the melting temperature is preferably from the melting point of the adhesive resin to about 300°C.

In addition, the adhesive resin (b) may contain additives commonly used for antioxidants, light stabilizers, antistatic agents, lubricants, antiblocking agents, tackifiers, and polyolefin resins, as necessary. It may be added as long as it does not impair the purpose of the present invention.

The ethylene content (hereinafter sometimes abbreviated as C ₂ ) of the ethylene/vinyl alcohol copolymer (c) is 50 mol% or less, preferably 20 to 35 mol%, since it has excellent gas barrier properties. This further improves gas barrier properties. Here, C ₂ (mol%) refers to the content of the ethylene component in the monomer units contained in the ethylene/vinyl alcohol copolymer (c).

The method for producing the ethylene/vinyl alcohol copolymer (c) is not particularly limited; for example, a copolymer of ethylene and fatty acid vinyl ester is produced according to a known method, and then this is hydrolyzed ( EVOH can be produced by saponification).

The degree of saponification of such ethylene/vinyl alcohol copolymer (c) is preferably in the range of 80% by weight or more since it has excellent gas barrier properties.

Furthermore, in addition to the ethylene unit and the vinyl alcohol unit, EVOH may have other structural units as long as they are in small amounts.

Such resins can be conveniently selected from commercially available products, and are commercially available, for example, from Kuraray Co., Ltd. under the trade names of EVAL, and from Mitsubishi Chemical Co., Ltd. under the trade names of Soarnol and G-Soarnol.

The melt mass flow rate at 190°C (temperature 190°C, load 2.16 kg, hereinafter abbreviated as "MFR _EVOH ") of such ethylene-vinyl alcohol copolymer (c) measured in accordance with ISO 1133 is the moldability And from the viewpoint of film appearance, the range is preferably 1.0 g/10 minutes or more and 8.0 g/10 minutes or less, more preferably 1.0 g/10 minutes or more and 6.0 g/10 minutes or less, and 1.0 g/10 minutes or more and 6.0 g/10 minutes or less. /10 minutes or more and 3.0 g/10 minutes or less is most preferable. In addition, the melt mass flow rate at 210°C (temperature 210°C, load 2.16 kg) of the ethylene-vinyl alcohol copolymer (c) measured in accordance with ISO1133 was 2.5 from the viewpoint of moldability and film appearance. The range is preferably 20.0 g/10 minutes, more preferably 2.5 to 15.0 g/10 minutes, and most preferably 2.5 to 7.5 g/10 minutes.

The density of the ethylene/vinyl alcohol copolymer (c) at 20°C measured in accordance with ISO1183-3 (hereinafter abbreviated as "D _EVOH ") is less than 1190 kg/m ³ from the viewpoint of film appearance and adhesion. It is preferably 1100 to 1180 kg/m ³ , more preferably 1140 to 1180 kg/m ³ .

In addition, in order to have excellent film appearance and adhesive properties, it is preferable that C ₂ (mol%) and D _EVOH (kg/m ³ ) of the ethylene/vinyl alcohol copolymer (c) satisfy the following formula (1), It is more preferable that the following formula (2) is satisfied.

D _EVOH <-4.265×C ₂ +1325 (1)
D _EVOH <-4.265×C ₂ +1315 (2)
Note that the slopes of formulas (1) and (2) were calculated using standard grade and semi-standard grade C ₂ and D _EVOH of ethylene/vinyl alcohol copolymers manufactured by Kuraray. Specifically, an ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., trade name EVAL L171B) containing 27 mol% of _{C2 and} 1210 kg/ ^m3 of D _EVOH , 32 mol% of _C2 , and 1190 kg/m3 of D _EVOH . Ethylene-vinyl alcohol copolymer with 35 mol% of _C2 and 1180 kg/ ^m3 of D _EVOH (manufactured by Kuraray Co., Ltd. ^, trade name: EVAL F171B) Ethylene-vinyl alcohol copolymer (product name: EVAL H171B, manufactured by Kuraray Co., Ltd.) with 38 mol% C ₂ and 1170 kg/m ³ of D _EVOH , 44 mol % C ₂ and 1170 kg/m 3 of D _EVOH . Ethylene-vinyl alcohol copolymer with 1140 kg/ ^m3 (manufactured by Kuraray Co., Ltd., trade name EVAL E105B), ethylene-vinyl alcohol copolymer with 48 mol% _C2 and 1120 kg/ ^m3 of _DEVOH (manufactured by Kuraray Co., Ltd.). ) Calculated from the correlation between C ₂ and D _EVOH of Kuraray product name EVAL G156B).
In the laminate of the present invention, the base material layer is composed of a composite base material (S) containing a cellulose material and a thermoplastic resin.

There are no particular limitations on the cellulose-based materials constituting the composite substrate (S), including mechanical pulp fibers, chemical pulp fibers, microfibrillated cellulose, nanocellulose materials such as cellulose nanofibers and cellulose nanocrystals, and pulverized paper products. Examples include films made of modified cellulose such as cellophane, and pulverized products thereof. Examples of such papers include kraft paper, high-quality paper, stretch paper, glassine paper, paperboard such as cup base paper and photographic paper base paper. As the cellulose material constituting the composite base material (S) of the present invention, one or more of these may be used.

Moreover, such cellulose may be subjected to a modification treatment. Examples of such modified cellulose include ester cellulose such as cellulose acetate, ether cellulose such as methyl cellulose, carboxyalkyl cellulose such as carboxymethyl cellulose, viscose, and rayon.

The thermoplastic resin constituting the composite substrate (S) is not particularly limited, and may include polyolefins, polyvinyl alcohol, polyesters, polyamides, polyacetals such as polyoxymethylene, and liquid crystal polymers such as polycondensates of ethylene terephthalate and parahydroxybenzoic acid. , cycloolefin polymers consisting of fluororesins such as polyvinylidene fluoride, crystalline thermoplastic resins such as polylactic acid and polyglycolic acid, and cyclic olefins such as norbornene, and ethylene, which is a copolymer of ethylene and cyclic olefins such as norbornene. Cycloolefin copolymer, polycarbonate, polyarylate which is a copolymer of bisphenol A and terephthalic acid, polyphenylene ether, modified polyphenylene ether which is a polymer alloy of polyphenylene ether and polystyrene (including impact-resistant polystyrene), polyvinyl chloride, Examples include amorphous thermoplastic resins such as polyphenylene sulfide, polyether sulfone, polyamideimide, polyetherimide, and polyester carbonate, and one or more of these may be used. Among these, the thermoplastic resin is preferably polyolefin and/or polyester because of its excellent secondary processability.

Examples of such polyolefins include homopolymers of α-olefins having 2 to 12 carbon atoms such as ethylene, propylene, and 1-butene, copolymers thereof, and copolymers of ethylene with vinyl esters and/or acrylic esters. Examples include merging.

For example, ethylene homopolymers such as high-pressure low-density polyethylene and high-density polyethylene, ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, ethylene/4- Ethylene polymers such as methyl-1-pentene copolymer, ethylene/vinyl acetate copolymer, ethylene/acrylic acid ester copolymer, ethylene/methacrylic acid ester copolymer, propylene homopolymer, propylene/ethylene copolymer, etc. Polymers, propylene/1-butene copolymer, poly-1-butene, poly-1-hexene, poly-4-methyl-1-pentene, and the like. The polyolefins may be used alone or in a composition of two or more.

In addition, such polyesters include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid, and ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,6- These include polycondensates of aliphatic diols such as hexanediol and cyclohexanedimethanol, or aromatic diols such as bisphenol A, and polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol, and terephthalic acid and 1,4-butane. Examples include polybutylene terephthalate, which is a polycondensate with diol, and polyethylene naphthalate, which is a polycondensate of 2,6-naphthalene dicarboxylic acid and ethylene glycol. Each of these aromatic dicarboxylic acids, aliphatic diols, and aromatic diols may be used alone or in combination of two or more.

The method for combining the cellulose material and thermoplastic resin in the composite base material (S) is not particularly limited, and may include dry blending of the cellulose material and thermoplastic resin pellets, melt kneading of the cellulose material and thermoplastic resin, An example is a mixture of fibers made of cellulose material and fibers made of thermoplastic resin.

Among such composite base materials (S), sheets made of melt-kneaded products of cellulose material and polyolefin and/or polyester, or pulp fibers and polyolefin fibers and/or polyester are used because they have excellent secondary processability. Preferably, the paper is a mixed paper made of fibers.

Such melt-kneaded products of cellulose-based materials and polyolefin and/or polyester are produced by Daicel Millize Co., Ltd. under the trade name Cellblen, which is a melt-kneaded product of pulp fiber and polypropylene, and is a product of crushed paper and polyolefin. A melt-kneaded product is produced by Environmental Management Research Institute Co., Ltd. under the trade name MAPKA, a melt-kneaded product of cellulose nanofiber and polyolefin is produced by Daio Paper Co., Ltd. under the trade name cellulose composite resin pellets, and Seiko PMC Co., Ltd. Each is commercially available under the brand name STARCEL. Further, a sheet made of a pulverized paper product and a melt-kneaded product of polyolefin is commercially available from Environmental Management Research Institute Co., Ltd. under the trade name MAPKA Sheet.

In addition, as a mixed paper made of fibers made of cellulose material and fibers made of thermoplastic resin, a mixed paper made of pulp fiber and polyester fiber is produced by Tomegawa Paper Co., Ltd. under the trade name of conversion sheet, and Hirose Paper Co., Ltd. Co., Ltd. under the product name HOS-PF, Kinsei Paper Co., Ltd. under the product name Airlaid, and Kinsei Paper Co., Ltd. under the product name Airlaid as a mixed paper of pulp fiber and polyolefin fiber. Daio Paper Co., Ltd. sells paper made with synthetic fibers as a mixed paper with polyester fibers, and Kinsei Paper Co., Ltd. sells it as Airlaid paper as a paper made with rayon fibers and thermoplastic resin fibers. Each is commercially available under the trade name of Chemical Bond.

The content of the cellulose material in the composite base material (S) is in the range of 25% by weight or more and 75% by weight or less, more preferably 35% by weight or more and 65% by weight, since it is excellent in secondary processability and the appearance of the laminate. % by weight or less, most preferably from 45% to 55% by weight. If the content of the cellulose material is less than 25% by weight, the appearance of the laminate will be poor, which is undesirable, and if it exceeds 75% by weight, the secondary processability will be poor, which is not preferred.

The basis weight (g/m ² ) or thickness (mm) of the composite base material (S) is not particularly limited and is appropriately selected depending on the application.

A laminate that is one embodiment of the present invention is characterized in that it includes at least a base material layer and (C) layer/(B) layer/(A) layer from the base material layer side, and these four components It may not only consist of the same, but may also contain other components, such as the (D) layer, (E) layer, and (F) layer. Specifically, base material layer/(C) layer/(B) layer/(A) layer, (D) layer/base material layer/(C) layer/(B) layer/(A) layer, base material Layer / (D) layer / (C) layer / (B) layer / (A) layer, (E) layer / Base material layer / (D) layer / (C) layer / (B) layer / (A) layer , base material layer / (E) layer / (D) layer / (C) layer / (B) layer / (A) layer, (F) layer / base material layer / (E) layer / (D) layer / ( Examples include C) layer/(B) layer/(A) layer. Note that the symbol / between layers indicates that they are adjacent layers.

Examples of the (D) layer, (E) layer, and (F) layer include layers formed from synthetic polymers, woven fabrics, nonwoven fabrics, metal foils, papers, cellophane, and the like. For example, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as nylon 6 and nylon 66, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-ethyl acrylate copolymer, ethylene- Polyethylene resins such as methacrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ionomer, polypropylene resin, polybutene, acrylic resin, polyvinyl alcohol, polymethylpentene, polyvinyl chloride, Examples include layers formed from synthetic polymers such as polyvinylidene chloride, polystyrene, polycarbonate, polyurethane, and cellulose resin. Furthermore, these polymer films and sheets may be further subjected to aluminum vapor deposition, alumina vapor deposition, silicon dioxide vapor deposition, or acrylic treatment. Furthermore, these polymer films and sheets may be printed using urethane ink or the like. Examples of the metal foil include aluminum foil and copper foil, and examples of paper include kraft paper, high-quality paper, stretch paper, glassine paper, and paperboard such as cup base paper and photographic paper base paper.

Among these laminates, at least the adjacent base material layer/(E) layer/(D) layer/(C) layer/(B) layer/(A) has excellent productivity and gas barrier properties. It is preferable that the laminate is a laminate including layers, in which the (E) layer is made of polyethylene (e) and the (D) layer is made of acid-modified polypropylene (d). Here, the polyethylene (a) constituting the (A) layer and the polyethylene (e) constituting the (E) layer may be independently the same or different, but from the viewpoint of productivity , more preferably have the same components. In addition, the acid-modified polypropylene (b) constituting the layer (B) and the acid-modified polypropylene (e) constituting the layer (D) may be independently the same or different; From this point of view, it is more preferable that the components are the same.
The extrusion lamination method for obtaining a laminate is not particularly limited, and various extrusion lamination methods can be exemplified, such as a tandem lamination method in which each layer is laminated in sequence, and a coextrusion lamination method in which several layers are laminated simultaneously. can. Among these, from the viewpoint of cost, (C) layer / (B) layer / (A) layer or (E) layer / (D) layer / (C) layer / (B) layer / (A) layer Preferably, they are formed simultaneously by a coextrusion lamination process. Most preferably, the (A) layer and the (E) layer are made of the same component, and the (B) layer and the (D) layer are made of the same component, which is a three-type, five-layer extrusion lamination method. In such an extrusion lamination method, the temperature of the resin is preferably in the range of 180 to 280°C, and the surface temperature of the cooling roll is preferably in the range of 10 to 50°C.

In addition, in extrusion lamination, immediately after the thermoplastic resin constituting the layer adjacent to the base layer is made into an extruded layer in a molten state, the adhesive surface of the base material of the layer is exposed to an oxygen-containing gas or an ozone-containing gas to form a base layer. It is preferable to use a method of bonding the material to the base material layer because it has excellent adhesiveness to the base material layer. When improving the adhesion between the thermoplastic resin and the base material using an ozone-containing gas, the amount of ozone gas to be treated is 0.5 mg or more of ozone per 1 m ² of the film made of the thermoplastic resin extruded from the die. Spraying is preferred.

In order to further improve the adhesion between the thermoplastic resin layer and the base material layer, the extrusion lamination method used to obtain the laminate is performed at a temperature that does not cause the resin of each layer to foam, for example, at a temperature of 30°C to 60°C. Heat treatment can be performed for 10 hours or more. Further, if necessary, the adhesive surface of the base material layer may be subjected to known surface treatments such as corona treatment, flame treatment, and plasma treatment. Furthermore, if necessary, an anchor coating agent may be applied to the base layer.

By performing secondary processing, the laminate can be molded into a container without heat sealing. Therefore, it has superior gas barrier properties compared to containers made by heat sealing. There is no particular limitation on such secondary processing, and examples include vacuum forming, pressure forming, vacuum pressure forming, drawing forming, press forming, and the like.

The laminate has a high film appearance, adhesion, and gas barrier properties against oxygen, etc., and has excellent secondary processability, so it can be used as a material for foods, beverages, pharmaceuticals, etc. that require these properties. It can be suitably used for packaging materials, containers, etc.

The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
(1) Melt mass flow rate (MFR)
MFR was measured in accordance with either JIS K6922-1 (1997) or ISO1133.
(2) Density Density was measured in accordance with either JIS K6922-1 (1997) or ISO1183-3.
(3) Melt tension (MS)
A capillary viscometer with a barrel diameter of 9.55 mm equipped with a die having a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 degrees and a heat-retaining chamber was set at a temperature of 190 °C in a thermostatic chamber set at 23 °C. (Toyo Seiki Seisakusho, trade name: Capillograph) was filled with 18 g of polyolefin, the piston descending speed was set to 10 mm/min, the take-up speed was 10 m/min, and the load (mN) required for take-off was taken as the melt tension (MS). It was measured.
(4) Migration Migration was performed by setting the rotational speed of each extruder to obtain the thickness described in the example (10/5/5/5/10 μm) at a processing speed of 50 m/min, and extruding the extruder from the T-die. The melted film was visually measured. The molten film directly under the die was observed, and the width where the EVOH layer generated at both ends of the molten film did not wrap around was measured, and the total sum at both ends of the molten film was defined as migration (mm). The smaller the migration, the better the productivity.
(5) Maximum processing speed/productivity The maximum processing speed is determined by adjusting the rotation speed and processing speed of each extruder so that the thickness of the laminate becomes the thickness described in the example (10/5/5/5/10 μm). The processing speed was increased in conjunction with the processing speed, and the processing speed at which film breakage occurred was defined as the maximum processing speed (m/min). The higher the maximum machining speed, the better the productivity; when the maximum machining speed was less than 20, it was evaluated as ×, when it was 20 or more and less than 50, it was evaluated as △, when it was 75 or more, it was evaluated as ○, and when the maximum processing speed was judged as △ to 〇, productivity was evaluated as good.
(6) Appearance of laminate The appearance of the laminate was evaluated by visually observing the base material side of the laminate obtained in the example. When noticeable unevenness occurred on the base material, it was evaluated as ×, when slight unevenness occurred, it was evaluated as △, and when no unevenness occurred, it was evaluated as ○, and the appearance was evaluated as good with a rating of △ to 〇.
(7) Vacuum forming/secondary workability A mold with a bottom inner diameter of 58.0 mm, a drawing depth of 5.8 mm, and a drawing angle of 10° (made of chemical wood, concave, multiple degassing holes (1 mmφ) The laminate obtained in the example was installed in a compact vacuum forming machine 450DT (manufactured by Formech) equipped with a vacuum forming machine (heating surface, (A) layer surface of the laminate, suction surface, composite base material (S) surface of the laminate). ), vacuum forming was performed with heater output settings such that the surface temperature of the heater was 500°C (Heater 1 84%, Heater 2 84%, Heater 3 94%, Heater 4 86%), heating time 30 seconds, and molding time 20 seconds. Ta. The laminate after vacuum forming was observed and the secondary processability was evaluated. × if the laminate is broken or cannot be shaped, △ if the surface that hits the mold is not sharp even though it can be shaped, 〇 if the surface that hits the mold is somewhat sharp, the surface that hits the mold is sharp If it was, it was marked as ◎, and if it was judged as △ to ◎, the secondary workability was considered to be good.

Example 1
As the polyethylene constituting the (A) layer and (E) layer, 30 weight of high-pressure low-density polyethylene (manufactured by Tosoh Corporation, trade name Petrocene 225) with an MFR of 3.7 g/10 min and a density of 923 kg/ ^m3 was used. 70 parts by weight of high-pressure low-density polyethylene (manufactured by Tosoh Corporation, trade name Petrocene 190) having an MFR of 4.0 g/10 minutes and a density of 922 kg/ ^m3 , and a single screw extruder. A low-density polyethylene composition (MFR _PO 3.9 g/10 minutes, density 922 kg/m ³ , MS _PO 33 mN) (A1) melt-kneaded at a resin temperature of 160° C. (manufactured by Plako Co., Ltd., diameter 40 mm) (A1) 80 parts by weight of polyethylene (A1) as adhesive resin constituting layer B) and layer (D), MFR 7.0 g/10 min, density 930 kg/m ³ , MAH content 0.60% by weight. 20 parts by weight of maleic anhydride-modified polyethylene (manufactured by SK Geo Centric Japan Co., Ltd., trade name: OREVAC G OE850, M1) was blended, and the resin was heated to a resin temperature of 160 mm using a single-screw extruder (manufactured by Placo Co., Ltd., diameter 40 mm). A polyolefin resin composition (MFR _ADD 4.4 g/10 min, density 926 kg/m ³ , MAH content 0.12% by weight) (B1) melt-kneaded at ℃ was mixed with ethylene/vinyl alcohol constituting layer (C). As a polymer, ethylene vinyl has an MFR _EVOH of 2.0 g/10 min, an ethylene content of 32 mol%, a degree of saponification of 100 wt%, a density of 1160 kg/m ³ and an MFR of 4.1 g/10 min at 210°C. Alcohol copolymer (manufactured by Kuraray Co., Ltd., trade name EVAL SP482B) (C1), a composite base material (S) of cellulose material and thermoplastic resin as the base material layer, a mixture of pulp fiber, polyolefin fiber, and polyester fiber. Paper (manufactured by Daio Paper Co., Ltd., trade name: synthetic fiber mixed paper, basis weight: 25 g/m ² , cellulose material content: 55% by weight) (S1) was used.

First, (A1) is supplied to a single screw extruder (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) having a screw with a diameter of 40 mmφ set at 260°C, and (B1) is supplied with a screw having a diameter of 40 mmφ set at 260°C. (C1) was supplied to a single screw extruder (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.), and (C1) was supplied to a single screw extruder (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) having a screw with a diameter of 40 mmφ set at 260 ° C. The sample was extruded through a T-die at a temperature of 260° C., and the extrusion rotation speed was set to the same as that used to create the extruded laminate film shown below, and migration was evaluated from the molten film. Next, on a PET film (manufactured by Toyobo Co., Ltd., trade name: Toyobo Polyester Film E5100) with a thickness of 25 μm, processing speed was 20 m/min, air gap length was 110 mm, (A1), (B1), (C1), We started extrusion lamination of 3 types and 5 layers so that (B1) and (A1) had a thickness of 10 μm, 5 μm, 5 μm, 5 μm, and 10 μm, respectively, and increased the extrusion rotation speed and processing speed in conjunction to reach the maximum processing speed. was evaluated. Immediately before extrusion lamination of three types and five layers, the adhesive surface with layer (E) was corona treated at a treatment intensity of 31 W min/m ² , and then processed at a processing speed of 50 m/min. Extrusion laminate molding of 3 types and 5 layers so that the air gap length is 110 mm and the thicknesses of (A1), (B1), (C1), (B1), and (A1) are 10 μm, 5 μm, 5 μm, 5 μm, and 10 μm, respectively. Then, the surface of the layer (E) that adheres to the composite base material (S1) of three types and five layers, which is in a molten state immediately after being extruded from the T-die, is treated with ozone at a treatment intensity of 78 mg/ ^m2 . , composite base material (S1), polyethylene (A1) ((E) layer), adhesive resin (B1) ((D) layer), ethylene/vinyl alcohol copolymer (C1) ((C) layer), adhesive A laminate was obtained in which polyethylene resin (B1) (layer (B)) and polyethylene (A1) (layer (A)) were laminated in this order. Using the obtained laminate, the appearance and secondary processability of the laminate were evaluated. The results are shown in Table 1.

Example 2
A sheet made of a melt-kneaded product of paper powder, which is a pulverized paper product, and polyolefin, as a composite base material (S) of cellulose material and thermoplastic resin, which is the base material layer (Product manufactured by Environmental Management Research Institute Co., Ltd.) A laminate was obtained after evaluating migration and maximum processing speed in the same manner as in Example 1, except for using MAPKA Sheet, thickness 0.37 mm, cellulose material content 51% by weight) (S2). . Using the obtained laminate, the appearance and secondary processability of the laminate were evaluated. The results are shown in Table 1.

Example 3
The polyethylene constituting layer (A) and layer (E) is high-pressure low-density polyethylene (manufactured by Tosoh Corporation, product name) with MFR _PO of 3.7 g/10 min, density of 923 kg/m ³ , and MS _PO of 105 mN. A laminate was obtained after evaluating migration and maximum processing speed in the same manner as in Example 1 except that Petrocene 225) (A2) was used. Using the obtained laminate, the appearance and secondary processability of the laminate were evaluated. The results are shown in Table 1.

Example 4
The polyethylene constituting the (A) layer and (E) layer is a high-pressure process low-density polyethylene (manufactured by Tosoh Corporation, trade name Petrocene 212) with an MFR _PO of 13 g/10 min, a density of 919 kg/m ³ , and an MS _PO of 13 mN. ) (A3) was used, but the migration and maximum processing speed were evaluated in the same manner as in Example 1, and then a laminate was obtained. Using the obtained laminate, the appearance and secondary processability of the laminate were evaluated. The results are shown in Table 1.

Comparative example 1
As a substitute for the composite base material (S) of cellulose material and thermoplastic resin that is the base layer, kraft paper (manufactured by Chuetsu Package Co., Ltd., unbleached kraft paper, basis weight 50 g/ ^m2 , cellulose material content 100% by weight) ) (S5) was used, but the migration and maximum processing speed were evaluated in the same manner as in Example 1, and then a laminate was obtained. Using the obtained laminate, the appearance and secondary processability of the laminate were evaluated. The results are shown in Table 1. The laminate broke during vacuum forming, resulting in poor secondary processability.

Comparative example 2
Paperboard (manufactured by Nippon Paper Industries Co., Ltd., uncoated cup paper) Basis weight 300 g/m ² Cellulose material content 100% by weight as a substitute for the composite base material (S) of cellulose material and thermoplastic resin that is the base material layer ) (S6) was used, but the migration and maximum processing speed were evaluated in the same manner as in Example 1, and then a laminate was obtained. Using the obtained laminate, the appearance and secondary processability of the laminate were evaluated. The results are shown in Table 1. Because the laminate could not be shaped during vacuum forming, it had poor secondary processability.

The laminate of the present invention can be used for laminates that require adhesive properties, gas barrier properties, and secondary processability, and is particularly suitable for laminates used for packaging materials for foods, drinks, pharmaceuticals, etc. be able to.

Claims (12)

A laminate including at least a base material layer and (C) layer/(B) layer/(A) layer adjacent to each other from the base material layer side, wherein the base material layer satisfies (i) to (ii). Composite base material (S), (A) layer is polyolefin (a), (B) layer is adhesive resin (b), (C) layer is made of ethylene vinyl alcohol copolymer (c) that satisfies (iii) composed of a laminate.
(i) Contains cellulose material and thermoplastic resin (ii) Content of cellulose material is 25% by weight or more and 75% by weight or less (iii) Ethylene content _C2 is 50 mol% or less The laminate according to claim 1, wherein the content of the cellulose material contained in the composite substrate (S) is 35% by weight or more and 65% by weight or less. The laminate according to any one of claims 1 to 2, wherein the cellulosic material contained in the composite substrate (S) is a pulverized product of pulp fiber and/or paper. The laminate according to claim 3, wherein the composite substrate (S) is a sheet made of a melt-kneaded product of a pulverized paper product and a thermoplastic resin containing polyolefin and/or polyester. The laminate according to claim 3, wherein the composite base material (S) is a mixed paper of pulp fibers, polyolefin fibers, and/or polyester fibers. The laminate according to any one of claims 1 to 5, wherein the polyolefin (a) satisfies (iv) to (vi).
(iv) Melt mass flow rate (MFR _PO ) measured according to JIS K6922-1 (1997) is 1.0 g/10 minutes or more and 10.0 g/10 minutes or less (v) Measured at a temperature of 190°C and a withdrawal speed of 10 m/min. The melt tension (MS _PO ) is 3 mN or more and 50 mN or less (vi) The product of MFR _PO (g/10 min) and MS _PO (mN) MFR _PO × MS _PO is 70 or more and 250 or less The laminate according to any one of claims 1 to 6, wherein the polyolefin (a) contains an ethylene/α-olefin copolymer and/or a high-pressure low-density polyethylene. The laminate according to any one of claims 1 to 7, wherein the adhesive resin (b) contains a maleic anhydride-modified polyolefin. Claims 1 to 8, wherein the C ₂ (mol%) of the ethylene-vinyl alcohol copolymer (c) and the density D _EVOH (kg/m ³ ) at 20°C measured according to ISO1183-3 satisfy the following formula (1). The laminate according to any one of the above.
D _EVOH <-4.265×C ₂ +1325 (1) Between the base material layer and the (C) layer, further including (E) layer/(D) layer, the (E) layer is adjacent to the base material layer, the (D) layer is adjacent to the (C) layer, The laminate according to any one of claims 1 to 9, wherein the (E) layer is composed of polyethylene (e) and the (D) layer is composed of adhesive resin (d). (C) layer / (B) layer / (A) layer, or (E) layer / (D) layer / (C) layer / (B) layer / (A) layer are formed simultaneously by coextrusion lamination, A method for manufacturing a laminate according to any one of claims 1 to 10. A method for manufacturing a container, comprising molding the laminate according to any one of claims 1 to 10 by secondary processing.