JPS649944B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a laminate useful as a material for various containers, a lid material, etc. Recently, blow-molded polyester resin containers and paper containers with polyester resin laminated on the inner surface have been used as containers for foods and beverages such as sauces, salad oil, soybean oil, sauces, dressings, cutlet cheese, and seasonings. ing. In order to improve the barrier properties, especially for containers containing sake etc.
It may also be necessary to laminate aluminum foil or plastic film onto the polyester resin layer. When extrusion coating polyester resin on paper, the polyester resin penetrates into the paper fibers, so the adhesive strength of the polyester resin-paper laminate is excellent, but the polyester resin-
In the case of aluminum foil (or plastic film) laminates, the above-mentioned penetration does not occur, so there is a drawback that the adhesive strength is insufficient. It is also possible to extrude coat polyester resin after applying an anchor coating agent on aluminum foil or plastic film, but since no suitable anchor coating agent has been found, it is difficult to find a laminate with satisfactory adhesive strength. The current situation is that it has not been obtained. As a result of various studies aimed at solving the above-mentioned problems with laminates, the present inventor has developed a specific resin composition as an adhesive layer between a base material made of aluminum foil or plastic film and a polyester resin layer. The inventors have discovered that the object can be achieved by using the present invention, and have completed the present invention. That is, the present invention provides the following laminate. In a laminate in which a base material made of aluminum foil or plastic film and a polyester resin layer are laminated via an adhesive layer, the adhesive layer contains 30 to 99 parts by weight of a linear copolymerized polyester resin and 70 to 1 part by weight of an epoxy resin. 1. A laminate comprising a resin composition comprising: In a laminate in which a base material made of aluminum foil or plastic film and a polyester resin layer are laminated via an adhesive layer, the adhesive layer contains 30 to 99 parts by weight of a linear copolymerized polyester resin and 70 to 1 part by weight of an epoxy resin. 100 parts by weight of a resin composition consisting of 100 parts by weight and 0.5 to 0.5 parts by weight of finely powdered polyolefin
250 parts by weight of a laminate. The constituent components of the adhesive used in the present invention are detailed below. (i) Linear copolymerized polyester resin: (a) Polyethylene terephthalate is used as a starting material, triethylene glycol and other diols are added to it, and a depolymerization reaction and a recondensation reaction based on a transesterification reaction with the diols are carried out. A modified ether type polyester resin in which ethylene glycol in polyethylene terephthalate is partially replaced with diol. (b) A linear random copolymer polyester resin in which 95 to 50 mol% of the acid component is a terephthalic acid residue and 20 to 70 mol% of the alcohol component is an ethylene glycol residue. In this case, the remaining 5 to 50 mol% of the acid components are aliphatic dibasic acids such as adipic acid and sebacic acid, isophthalic acid,
It may consist of residues of aromatic dibasic acids such as orthophthalic acid and diphenylcarboxylic acid, and the remaining 80 to 30 mol% of the alcohol component.
is 1,2-propylene glycol, 1,3
- Glycol residues such as propylene glycol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, or oxyacid residues such as oxybenzoic acid Also good. (ii) Epoxy resins used in combination with the linear copolymer polyester resin mentioned above include not only epoxy resins alone, but also amines, polyamides, acid anhydrides, phenolic resins, butylated melamine formaldehyde resins, butylated urea, It may also contain a curing agent such as formaldehyde resin. The composition of the present invention, which uses a linear copolymerized polyester resin and an epoxy resin in combination, does not reduce the adhesiveness to the polyester resin layer.
Improves adhesion to base materials such as plastic films such as polyethylene terephthalate, vinyl chloride resin, low, medium and high density polyethylene, polypropylene, nylon, polycarbonate, polystyrene, cellophane and aluminum foil. In addition, when an adhesive layer is first formed on the base material surface and then once wound up to form a polyester resin layer again in an off-line method, the blocking resistance of the adhesive layer can be improved. The amount of epoxy resin relative to the linear copolymerized polyester resin is determined from 30 to 99 parts by weight of the former to 70 parts by weight of the latter, taking into account the mutual compatibility of both resins, the adhesion to the polyester resin layer and the base material, etc.
It is preferable to set it as 1 part by weight. If the latter is less than 1 part by weight, no effect of improving adhesion is observed, while if it exceeds 70 parts by weight, the adhesion to the polyester resin layer tends to decrease. (iii) Finely powdered polyolefin resin mixed in a proportion of 0.5 to 250 parts by weight with respect to 100 parts by weight of the above-mentioned linear copolymerized polyester resin and epoxy resin: When blending finely powdered polyolefin,
The adhesiveness to the polyester resin layer can be greatly improved, and the blocking resistance of the adhesive layer can be improved. Examples of the fine powder polyolefin resin include low, medium and high density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer and the like. The particle size of polyolefin resin fine powder is the average diameter
The thickness is preferably about 10 to 50 μm. If the average particle size is less than 10 μm, blocking resistance will not be sufficiently improved.
On the other hand, if it exceeds 50 μm, adhesiveness tends to decrease. The amount of the finely powdered polyolefin resin added to 100 parts by weight of the linear copolymerized polyester resin is usually 0.5 to 250 parts by weight. When the amount added is less than 0.5 parts by weight, no improvement in the effect is substantially observed, and when it exceeds 250 parts by weight, the adhesive strength is rather reduced. The polyester resin to be laminated with the base material such as aluminum foil or plastic film is polyethylene terephthalate, isophthalic acid, p-
Modified polyethylene terephthalate modified with oxybenzoic acid, methoxypolyethylene glycol, pentaerythritol, etc., and a blend of these resins with at least 30% by weight of at least one of rosin, terpene resin, petroleum resin, wax, ethylene-vinyl acetate resin, etc. refers to the resin that has been The laminate of the present invention is usually manufactured as follows. First, an organic solvent solution or aqueous emulsion containing the adhesive component of the present invention is applied onto a base material such as aluminum foil or plastic film by gravure coating, roll coating, etc., and dried.
Next, on the formed adhesive layer, a polyester resin is directly melt-extruded coated, a heated and melted polyester resin is applied in layers by gravure coating, roll coating, etc., or a polyester resin film is thermocompression bonded. let Formation of the polyester resin layer may be performed subsequent to the formation of the adhesive layer, or alternatively, after the adhesive layer is formed, it is wound up into a coil shape, and after a predetermined time elapses, it is unwound to form the polyester resin. It's okay. The thickness of the adhesive layer should be 0.1 to 10 μm after comprehensive consideration of pinhole prevention, adhesion, economic efficiency, etc.
The thickness of the polyester resin layer is preferably about 5 to 50 μm, more preferably about 10 to 40 μm. In addition, in order to further improve the adhesive strength between the base material and the polyester resin layer in the laminate and to more effectively prevent delamination between the two, as is done in the production of known laminates. , the laminate may be heated afterward. In addition, in the laminate of the present invention, paper, cellophane, plastic film, etc. can be further laminated on the surface of a base material such as aluminum foil or plastic film via an adhesive according to a known method. When paper is laminated on the outer layer, any printing can be carried out, so it is advantageously used as a decorative container. Examples 1 to 5 300 g of a toluene-methyl ethyl ketone (weight ratio 8:2) mixed solution containing modified ether type polyester resin A and epoxy resin B in various ratios shown in Table 1 below and having a resin concentration of 10% by weight. / ^m2 cup raw material - 15μm low density polyethylene - 7μm
The adhesive layer was applied onto an aluminum substrate made of aluminum foil and dried to form an adhesive layer with a thickness of 1.5 μm. Next, polyethylene terephthalate resin was melt-extruded onto the adhesive layer obtained above using a 65 mmφ extruder at a molten resin temperature of 280° C. through a T-die to form a layer of 30 μm. The adhesive strength (T peel) between polyethylene terephthalate and aluminum foil in each of the obtained laminates is as shown in Table 1. Each laminate is
It demonstrated excellent strength, durability, and barrier properties as a material for various containers. Comparative Examples 1-2 A laminate was obtained in the same manner as in Examples 1-5 except that the resin blending ratio was as shown in Table 1. The adhesive strength of both laminates is very weak as shown in Table 1, so
It cannot be used as a container material.

[Table] Examples 6 to 10 80 parts by weight of modified ether type polyester resin A and 20 parts by weight of epoxy resin B were dissolved in a mixture of toluene and methyl ethyl ketone (8:2), and a second polyethylene fine powder C having an average particle size of 20 μm was dissolved. Add in the proportions shown in the table to prepare an adhesive composition with a total resin solids concentration of 10 parts by weight. A 49g/ ^m2 single-gloss kraft paper and a 7μm aluminum foil are pasted together using a vinyl acetate adhesive, and at the same time, the adhesive composition obtained above is applied in-line to the surface of the aluminum foil, dried, and 2μm
While forming an adhesive layer, the product is wound into a coil with the adhesive layer facing inside. Next, while unwinding the coil, a polyethylene terephthalate resin layer is formed on the adhesive layer in the same manner as in Example 1 to obtain a laminate of the present invention. The adhesive force between aluminum foil and polyethylene terephthalate in each laminate is in the range of 300 to 500 g/15 mm width, and composite cans (spiral-wound cans) made using these laminates can be used for liquids such as beer and youth. It exhibited excellent properties as a container without causing delamination. Furthermore, even in the state of the coil prior to the formation of the polyethylene terephthalate layer, no blocking phenomenon occurred and it was possible to easily unwind it. Comparative Examples 3 to 5 Whether to add polyethylene fine powder (Comparative Example 3)
A laminate is obtained in the same manner as in Examples 6 to 10, except that a small amount (Comparative Example 4) or an excessive amount (Comparative Example 5) is added. The resin blending ratio is as shown in Table 2. If polyethylene fine powder is not added or only a small amount is added, a blocking phenomenon will occur in the rolled up state after the adhesive layer is formed, so it is practically impossible to obtain a laminate using the methods of Examples 6 to 10. It turns out that there is something. On the other hand, if an excessive amount of polyethylene fine powder is used, although the blocking phenomenon is completely prevented, the adhesive force becomes less than 50 g/15 mm width, making it difficult to put it to practical use.

【table】

Claims (1)

[Scope of Claims] 1. A laminate in which a base material made of aluminum foil or plastic film and a polyester resin layer are laminated with an adhesive layer interposed therebetween, wherein the adhesive layer contains 30 to 99 parts by weight of a linear copolymerized polyester resin. and 70 to 1 part by weight of an epoxy resin. 2. A laminate in which a base material made of aluminum foil or plastic film and a polyester resin layer are laminated via an adhesive layer, in which the adhesive layer contains 30 to 99 parts by weight of a linear copolymerized polyester resin and 70 to 1 part by weight of an epoxy resin. Resin composition consisting of 100 parts by weight
1. A laminate comprising a mixture of parts by weight and 0.5 to 250 parts by weight of finely powdered polyolefin.