JPS5874354A - Manufacture of laminate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a laminate with good barrier properties.

In general, high barrier properties are required for packaging materials for oil-containing foods that are at risk of oxidation, foods that are expected to brown due to oxidation, and pharmaceutical solutions.

Examples of such materials having high barrier properties include polyvinyl alcohol, polyvinylidene chloride, polyacrylonitrile, polyamide, saponified ethylene-vinyl acetate copolymer, and the like.

Among these, various laminates using saponified ethylene-vinyl acetate copolymers have been developed and proposed.

For example, a laminate using a film made of saponified ethylene-vinyl acetate copolymer as the intermediate layer, dry laminating a base sheet on one side and a heat-adhesive film on the other side; A laminate obtained by sand laminating or dry laminating a multilayer film having a polyolefin layer and a saponified ethylene-vinyl acetate copolymer layer with a base sheet, including at least a saponified ethylene-vinyl acetate copolymer layer Laminated products are known in which a film is extruded and laminated onto a base sheet, and then a heat-sealable film is further dry-laminated or a heat-sealable resin is extrusion coated.

As a result of various studies to produce a laminate including a saponified ethylene-vinyl acetate copolymer layer as described above, the inventor of the present invention has discovered that ethylene-vinyl acetate can be produced using a simple, extreme-pressure method that requires only -1 extrusion lamination. The present invention was completed by demonstrating that it is possible to produce a Hiko laminate that has a saponified copolymer layer, has high barrier properties as a packaging material, and can be used as is.

That is, the gist of the present invention is to combine at least a resin containing a saponified ethylene-vinyl acetate copolymer 10 to 100 parts by weight, and a resin containing at least 30 parts by weight of a polyethylene resin. When the resin is laminated on one surface (extrusion lamination is performed to produce an extruded laminate, and then immediately after the extrusion lamination of the extruded laminate, at least a surface portion thereof is in a molten state) is a resin layer containing a polyethylene resin. ozone treatment by spraying ozone-containing gas onto the surface of the extruded laminate, and
A laminate characterized in that a separately manufactured base sheet whose surface has been subjected to an anchor coat treatment is laminated so that the ozone-treated surface of the former and the anchor coat-treated surface of the latter face each other, and is suppressed and cooled. This is the manufacturing method.

Generally, methods for obtaining laminates by extrusion lamination of saponified ethylene-vinyl acetate copolymers have been known, but saponified ethylene-vinegar-vinyl copolymers decompose when heated to high temperatures. It is necessary to process at a temperature below 230°C. Therefore, in consideration of adhesion to the base sheet, an isocyanate-based anchor coating agent must be used, and the layer in contact with the base sheet must contain a saponified ethylene-vinyl acetate copolymer. Moreover, the actual situation is that it is difficult to select an anchor coating agent and sufficient adhesive strength cannot be obtained. 230℃ with coating agent
It was possible to sufficiently adhere the four base sheets at the following extrusion temperature.

The saponified ethylene-vinyl acetate copolymer in the present invention refers to a saponified ethylene-vinyl acetate copolymer having an ethylene content of 0-SO mole so that the degree of saponification is 93% or more, preferably 114 or more. It is obtained by saponification.

In addition, in the present invention, the polyethylene resin includes polyethylene, ethylene, 70 pyrene, butene,
α-olefins such as pentene, hexene, ofnonene, decene, co-methylbentene-1, or vinyl acetate,
Acrylic acid, methacrylic acid, ethyl acrylate, vinyl alcohol Cape Nanatsuma τ, maleic acid, fumaric acid,
It is one or more copolymers of unsaturated carboxylic acids such as itaconic acid and hymic acid or their anhydrides. Alternatively, the acid groups of a copolymer containing acid groups may be ionized with a metal such as N-transformed Mg or ZζAt.

Next, in the present invention, any resin that can be blended with the saponified ethylene-vinyl acetate copolymer may be any resin that can be blended, such as those listed above as polyethylene resins, Ruru, or polyamide. I don't mind. In particular, in the present invention, it is preferable to include a partially saponified ethylene-vinyl acetate copolymer in the form of an ethylene-vinyl acetate-vinyl alcohol copolymer. In the present invention, the best blend composition with high barrier properties and transparency is ethylene-vinyl acetate copolymer saponified III! Ij″-100% by weight,
Partially saponified ethylene-vinyl acetate copolymer o-tsx
Amount: ethylene-vinyl acetate copolymer θ~to*Ik%
It is. Alternatively, metal ionized products of ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer may be used.

Next, in the present invention, any resin layer may be used as the resin layer other than the resin layer containing saponified ethylene-vinyl acetate copolymer and the resin layer containing polyethylene resin. .

However, it is necessary to give sufficient consideration to the adhesiveness between each resin layer. For example, in the case of 100 saponified ethylene-vinyl acetate copolymers, both sides are made of polyamide or unsaturated carboxylic acids such as acrylic acid, maleic acid, fumaric acid, itaconic acid, and hymic acid, or their anhydrides. Modified polyolefins are preferred.

Next, in the present invention, the resin layer containing the saponified ethylene-vinyl acetate copolymer and the resin layer containing the polyethylene resin may be the same in some cases.

For example, as a resin layer containing polyethylene resin,
The resin layer may be composed of 70 to 70 parts by weight of a saponified ethylene-vinyl acetate copolymer and 90 to 30 parts by weight of a polyethylene resin.

In this case, the polyethylene resin layer containing the saponified ethylene-vinyl acetate copolymer is treated with ozone.

Next, the ozone-containing gas in the present invention can be obtained by supplying air or oxygen to a normal ozone generator, but in the present invention, the ozone-containing gas contains a polyethylene resin whose surface at least is in a molten state. A gas with an ozone concentration tL9 is applied to one side of the resin layer.
It is preferable to spray at the above ratio.

Next, the base sheet in the present invention refers to a base sheet that is conveniently used in the conventional manufacturing method of this type of laminate, such as paper, metal foil such as aluminum foil, cellophane, polypropylene, polyamide, polyester. , unstretched or stretched films of various plastics such as polystyrene and bocarbonate, laminated films in which these films are coated with machine-grade resins such as polyvinylidene chloride and nitrified cotton, and lamination of two or more of these films. laminate sheets, etc. These various base material sheets are coated with an anchor coating agent such as an organic titanate, polyethyleneimine, a compound having an isocyanate group, etc. on the surface to be adhered to the film whose surface portion is in a molten state. If it is necessary to have a small layer, the surface of the base sheet F can be subjected to a four-discharge treatment and a general adhesion improvement treatment for fire disposal parts.

Next, a method for manufacturing a laminate according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a transverse wave explanatory diagram showing an example of the method for manufacturing a laminate according to the present invention in the order of steps. As shown in FIG. 1, an ozone generator (1) is supplied with air or gas (2) from an oxygen cylinder using a blower or compressor.

On the other hand, in the present invention, at least ethylene-vinyl acetate copolymer saponified eyelid lO~1 is produced from the extrusion die (3).
00 weight - and polyethylene resin 30
The extruded laminate (4) is produced by extruding and laminating the resin containing the polyethylene resin on one surface, and then the extruded laminate (4).
The surface of a resin layer containing polyethylene resin, at least the surface portion of which is in a molten state immediately after extrusion lamination (
Ozone-containing gas is sprayed onto Al from the ozone generator (connected to 11&C) through a nozzle with a pore provided in the tube (6) to produce an ozone-treated extruded laminate (button).

On the other hand, the ozone-treated extruded stack was prepared by spraying the ozone-containing gas onto a base sheet (7) having an anchor coat layer (6) made of a separate anchor foot agent, and the ozone-treated surface and base sheet The anchor coat layer (7) is laminated so that the (6) side faces each other, and is simultaneously pressed, cooled, and crimped using a nip roll (8) and a chill roll (9) at a temperature of about 1s°C. The laminate aυ of the present invention can also be obtained.

As detailed above, according to the present invention, it is possible to provide a layer containing a saponified ethylene-vinyl acetate copolymer on a base sheet with sufficient adhesive strength by extrusion coating. The laminate material has good barrier properties.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 Low density polyethylene (MI=
iz, a==avz7) Modified low-density polyethylene graft copolymerized with maleic anhydride (MI=Us, d=Q
Del) Saponified ethylene-vinyl acetate copolymer (ethylene content 35 mol, saponification rate deqo'%') was mixed into 10μ of low-density polyethylene/modified low-density polyethylene Sμ/1 body of ethylene-vinyl acetate copolymer The layer structure and thickness of saponified IO voice/modified low-density polyethylene and lenjμ/low-density polyethylene IOμ are extrusion molded at COCOQ°C, and the surface portion of the obtained film is molten on one side, where ozone is generated. A stainless steel gas blower with a nozzle connected to the machine sprays ozone uniformly from the tube at a ratio of ozone concentration/jl of air, and then
This film was closely pressed with a separate biaxially oriented polypropylene having a thickness of 20 .mu.m and a base sheet 1 having an anchor coating agent (Takerac Cart Layer) to obtain a laminate.

The adhesive strength of this laminate is 4Iλof/ls*m. In addition, the oxygen gas permeability is 53-24' Hr (RE deo
s>.

Example 3 From a three-layer coextrusion die, ethylene-vinyl acetate copolymer (MI = '2j, d = = 0923, va content = 6ch)
and saponified ethylene-vinyl acetate copolymer (ethylene content 35 mole, saponification rate qqo@) soM amount*,
Partially saponified ethylene-vinyl acetate copolymer [manufactured by Toyo Shoji Co., Ltd.: Mersen H-44110D'JSO weight] was mixed with a blend of ethylene-vinyl acetate copolymer 10μ/EV
A saponified product - EVAg component saponified product 20μ / ethylene-vinyl acetate copolymer" 10μ layer structure and thickness
Ozone-containing gas was sprayed on one side of the obtained film in a molten state in the same manner as in Example 1, and then the film was closely pressed against the base sheet to form a laminate. I got it. The adhesive strength of this laminate is 3101
／ ・／ It was j@l. Further, the oxygen gas permeability was / j"l @J I Hr←unv0%).

Example 3 Low-density polyethylene 7 (M1=
1! , a = (A9/l), EvA saponified product (ethylene content 35 mol, saponification rate de 9.θ%), Is weight %,
EVA partially saponified product [Dumilan c- manufactured by Takeda Pharmaceutical Co., Ltd.
ts-〇〇〕1O1iliti, ethylene-vinyl acid copolymer (MI='2S.

d=Q Day 3, a blend containing Va and t=>as wt. Extrusion molding was carried out at 10° C., and ozone-containing gas was blown onto the blend layer surface, where the surface portion of the obtained film was in a molten state, in the same manner as in Example 1, and then the film was brought into close contact with the base sheet and pressed. A laminate was obtained. The adhesion strength of this laminate was 100%. Also, the oxygen gas permeability was -s'3・J 4I
Hr(nHvots).

A simple explanation of Gfl/If 1st
The figure is a schematic explanatory diagram showing an example of a method for producing a laminate according to the process order.

Claims (1)

[Scope of Claims] A resin containing a resin is extruded and laminated to form an extruded laminate on one surface, and then the extruded laminate σ) A polyethylene resin whose surface portion is at least in a molten state immediately after extrusion lamination. The surface of the resin layer containing ozone is sprayed with an ozone-containing gas to perform ozone treatment, and then the above extruded laminate and the surface are subjected to anchor coating treatment, and a separately manufactured base sheet. A method for producing a laminate, characterized in that the ozone-treated surface of the former and the anchor coat-treated surface of the superior are laminated so as to face each other, and then suppressed and cooled. (21 Saponified ethylene-vinyl acetate copolymer/θ~i
The resins containing 0% by weight are saponified ethylene-vinyl acetate copolymer 10-100% by weight, partially saponified ethylene-vinyl acetate copolymer 0% by weight, and ethylene-vinyl acetate copolymer Q~ 5% by weight of g.