JPH02223448A - Composite film - Google Patents

Abstract

PURPOSE:To improve the workability of a composite film by a method in which after the coating layer of sol plus the vinyl chloride copolymer containing adhesion-imparting agent has been formed on both surfaces of the film with gas barrier property, said materials are heated, thereby forming an adhesion film. CONSTITUTION:The both surfaces of the film with gas barrier property is coated with the composition of sol plus the polyvinyl copolymer containing an adhesion- imparting agent, whereby a coater layer is provided. Next, the coating layer is heated and melted at most the dissociating temperature of polyvinyl chloride copolymer and at least said dissociating temperature, and it is solidified. The gelling film of polyvinyl chloride stuck firmly to the surface of said film is formed, and a composite film is obtained. The obtained composite film may be easily composited with the different material compatible with vinylchloride resin such as nitrile rubber and butyl rubber. The weld working of the composition films to each other may be achieved by the operation of a welder.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to applications where gas barrier properties are desired, such as diaphragms, air-extraction materials, packaging materials, and pneumatic toys such as radio-controlled airships. As a film, it not only has gas barrier properties, but also
The present invention relates to a composite film that has excellent secondary processability such as thermoformability and welder processability.

[Conventional technology]

Conventionally, gas barrier properties have been essential in flexible packaging, especially in the field of food and fragrance packaging, and depending on the application, performance such as transparency, printability, non-static properties, heat-sealability, and unsealability are also required. is desired. For this reason, the base material is polyvinylidene chloride, saponified ethylene vinyl acetate copolymer, polyvinyl alcohol film, which has gas barrier properties, and is laminated with nylon resin, polyethylene resin, cellophane, ethylene vinyl acetate copolymer resin, ionomer resin film, etc. It has been developed and provided for a variety of uses.

On the other hand, in fields other than food and flexible packaging applications, thinner walls and lighter weights are progressing, and similar demands are being made for gas barrier materials. For example, materials such as metal, nitrile rubber, and butyl rubber have traditionally been used for diaphragm applications, but metals have limited applications because they are difficult to shape and cannot be applied to complex product shapes. On the other hand, elastomers such as nitrile rubber and butyl rubber are easy to mold, but have the disadvantage of poor gas barrier properties. In addition, since the advertising radio-controlled airships that have been seen from time to time are lightweight and come in a wide variety of complex shapes, a simple welder bonding method is desired as the bonding method. The above-described laminate film for food packaging does not take into consideration the heat-pressing molding and welder adhesion processability at all.

[Problem to be solved by the invention]

However, the present inventors have developed a lightweight, thin-walled material based on a material with gas barrier properties, and developed a rubber vulcanization condition of 130°C to 15°C.
As a result of extensive research into a composite film that can be molded under heat and pressure at 0°C heating time (15 to 30 minutes) and is suitable for welder bonding as an adhesive processing method, we found that an adhesion-imparting agent was added to the gas barrier film. The present inventors have discovered that a composite film prepared by coating a vinyl chloride polymer plastisol containing a polyvinyl chloride polymer and forming a film by heating and melting is suitable for the above-mentioned purpose, leading to the present invention.

That is, an object of the present invention is to provide a thin, lightweight composite film that is a gas barrier film that has heat-pressing moldability and welder bonding processability.

[Means to solve the problem]

In order to achieve the above object, in the present invention, a coating layer made of a polyvinyl chloride polymer plastisol composition containing an adhesion promoter is formed on both surfaces of a gas barrier film, and the coating layer is heat-treated. It is gelled and formed into a film to form an adhesive film, resulting in a composite film.

In detail, the vinyl chloride polymer, which is the main component of the plastisol composition used in the present invention, is prepared by combining vinyl chloride or a mixture of vinyl chloride and a comonomer copolymerizable therewith with an emulsifier and water-soluble polymerization. Particle size produced by emulsion polymerization in the presence of an initiator: 5μ or less, preferably 0.0
In the presence of a paste resin of about 5 to 3 microns, or a dispersant and an oil-soluble polymerization initiator, the whole or part of vinyl chloride or a mixture of vinyl chloride and a comonomer copolymerizable therewith is mechanically finely dispersed and then polymerized. This is a resin for mixing base resin or paste resin manufactured by a fine suspension polymerization method. In addition, a vinyl chloride resin with a large particle size produced by ordinary suspension polymerization may be used in combination as long as it does not adversely affect the viscosity, fluidity, processability, etc. of the paste sol.

Examples of comonomers that can be copolymerized with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate;
Examples include acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate and ethyl methacrylate, maleic esters such as dibutyl maleate, vinyl ethers such as vinyl methyl ether vinyl butyl ether, etc. Species or more is less than 30M amount%, preferably 20% by weight
Used in the following ranges.

The plasticizer that is one component of the plastisol composition is not particularly limited as long as it is used for vinyl chloride polymers, but for example, dibutyl phthalate, di-n-phthalate, etc.
Phthalate plasticizers such as octyl and di-2-ethylhexyl phthalate, fatty acid ester plasticizers such as di-2-ethylhexyl adipate and dibutyl sebacate, phosphoric acid esters such as tricresyl phosphate, trioctyl trimellitate, etc. Examples include epoxy plasticizers such as trimellitic acid esters and epoxidized soybean oil, and these may be used alone or in combination of two or more.

The amount of plasticizer used depends on the solid content concentration required for the paste sol,
It is selected appropriately depending on the fluidity or the use of the composite, but it is usually 40 to 40 parts by weight per 100 parts by weight of the vinyl chloride polymer.
It is preferable to select it within the range of 100 parts by weight. Further, part of the plasticizer can be replaced with a diluent such as mineral spirit or texanol isobutyrate, thereby reducing the amount of plasticizer used.

The plastisol composition contains blocks of diisocyanate polymers, preferably long chain alkylphenol blocks or oxybenzoic acid ester blocks of diisocyanate polymers, in order to impart adhesive properties to it or to enable it to be used as an adhesive. Contains it as an ingredient.

It is preferable to use a diisocyanate polymer block having an average molecular weight in the range of 1,000 to 10,000.

If the average degree of polymerization of the block is less than 1,000, the anchoring effect as an adhesive cannot be sufficiently exhibited and the adhesive strength is insufficient.On the other hand, if it is greater than 10,000, the sol composition will significantly deteriorate. This is undesirable as it causes an increase in the viscosity.

Therefore, the diisocyanate monomers constituting the diisocyanate polymer include, for example, fatty acid diisocyanates such as hexamethylene diisocyanate and lysine isocyanate, alicyclic diisocyanates such as hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, and hydrogenated tolylene diisocyanate, and tolylene diisocyanate. , aromatic diisocyanates such as diphenylmethane diisocyanate and xylene diisocyanate.

Among these, aromatic diisocyanates, particularly tolylene diisocyanate and diphenylmethane diisocyanate are preferred. The diisocyanate polymers can then be prepared, for example in inert solutions such as ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane chlorobenzene, or in plasticizers such as phthalates, phosphates, adipates or trimellitates. catalysts such as tertiary amines, alkali metals of Mannich base fatty acids, alcolades, etc., by known methods, followed by blocking agents such as long-chain alkylphenols and oxybenzoic acid esters. A blocking reaction is carried out to produce a long chain alkylphenol block or oxybenzoic acid ester block of diisocyanate polymer. As the diisocyanate polymer used in the present invention, it is particularly preferable to use one containing an isocyanurate ring obtained by polymerizing diisocyanate monomers. Those containing isocyanurate rings are produced according to the method described above. Of course, the diisocyanate polymer may also be a so-called isocyanate group-terminated polyurethane, polyurea, etc. obtained by the reaction of a diisocyanate and an active hydrogen compound. The alkylphenol used as a blocking agent is a phenol having an alkyl group having 4 or more carbon atoms as a substituent, such as butylphenol,
Examples of the oxybenzoic acid ester include hexylphenol, octylphenol, nonylphenol, and the like, and examples of the oxybenzoic acid ester include ortho, meta, and para oxybenzoic acid esters, with rose-substituted esters being particularly preferred. One group constituting the oxybenzoic acid ester is, for example, a long chain alkyl group such as a meta- and para-substituted group such as an n-heptyl group, n-octyl group, Z-ethylhexyl group, nonyl group, or dodecyl group,
An alkoxyalkyl group having a long-chain polyoxyethylene group or a polyoxypropylene group bonded thereto, or an alkoxyalkyl group having an oxyethylene group or an oxypropylene group bonded to a long-chain alkyl group are preferred. The appropriate amount of the blocking agent to be used is approximately equivalent to the free isocyanate groups of the diisocyanate polymer. The amount of the blocked diisocyanate polymer added is preferably in the range of 1 to 25 parts by weight per 100 parts by weight of the vinyl chloride polymer.
The active NGO content in the plastisol composition is 0.03 to 1% by weight, preferably 0.03 to 0.6% by weight, especially 0.05% by weight.
Preferably, it is present in a range of 0.5% by weight. If the effective NGO content is less than 0.03% by weight, the adhesive effect will be small, and if it is more than 1% by weight, the sol viscosity will increase.
Unfavorable phenomena such as coloring are likely to occur. The plastisol composition used in the present invention includes an adhesion imparting agent,
For example, it is preferable to contain an accelerator for dissociating blocks of the oxybenzoic acid ester blocked diisocyanate polymer.

Examples of the dissociation promoter include inorganic or organic compounds of alkali metals, and inorganic or organic compounds of metals such as lead, tin, cadmium, and zinc, and it is desirable to use at least one of these. Examples of the alkali metal compound include fatty acids, especially fatty acids whose alkyl group has 8 to 18 carbon atoms, alkyl sulfuric acids, alkyl sulfonic acids, or potassium salts and sodium salts of polyoxyethylene adducts thereof;
Further examples include composite stabilizers used as stabilizers for polyvinyl chloride polymers, such as potassium-zinc, sodium-zinc, calcium-zinc, barium-zinc, and cadmium-barium-zinc group stabilizers. . Metal compounds other than alkali metals include inorganic metal compounds such as lead white basic lead silicate, dibasic lead sulfate, and zinc white, lauric acid, stearic acid, ricinoleic acid, salicylic acid, and 2-ethylhexoin. Examples include metal salts of fatty acids or resin acids such as cadmium, barium, calcium, zinc, lead, tin, or magnesium, and organic compounds such as zinc octylate, dibutyltin laurate, dioctyltin maleate, and dibutyltin mercaptide. The amount added is not particularly limited, but usually vinyl chloride polymer 1
0.5 to 10 parts by weight, preferably 1
~5 parts by weight can achieve that purpose.

The gas barrier film that serves as the base material of the composite film of the present invention is not particularly limited as long as it has gas barrier properties, such as hynylidene chloride resin,
Examples include films of polyvinyl alcohol, ethylene-vinyl acetate copolymer saponified resin, and the like. Among these, biaxially stretched polyvinyl alcohol film is particularly suitable.

Compared to polyvinyl alcohol, vinylidene chloride resin is easily thermally decomposed and has a heat shrinkage rate of 5% to 30% at 100°C.
In the case of saponified ethylene-vinyl acetate copolymer resin, the heat shrinkage rate is 1% to 2% at 150°C, which is equivalent to biaxially oriented polyvinyl alcohol, but the melting point is 180°C.
Since the temperature is around °C, it has the disadvantage that it tends to flow during hot and pressure molding, so it is desirable to use it properly depending on the purpose.

The polyvinyl alcohol used as the biaxially stretched film has a polymerization degree of 800 to 23, which is relatively easy to adjust.
At around 00, the degree of saponification is 98%, which is said to be complete saponification.
It is desirable to use mol % or more. When the saponification degree is 98 mol% or less, the solubility in water becomes high,
The humidity dependence of gas barrier properties also tends to increase.

Although the film is formed by a biaxial stretching method, either a sequential two-wheel stretching method or a simultaneous two-wheel stretching method may be used. Even if the stretching method is different,
The stretching ratio is in the range of 2 to 4 times in both the length and width, and usually about 3 times is suitable.

If the stretching ratio is 4 times or more, the stretching process is difficult and the processing yield tends to be extremely poor, and if the stretching ratio is 2 times or less, the gas barrier properties and mechanical properties become poor.

After biaxial stretching, it is heat set at 170-220°C.

The biaxially stretched polyvinyl alcohol film thus obtained is highly crystallized and oriented with a degree of crystallinity of approximately 45 to 55%, resulting in a gas barrier film with excellent mechanical strength.

The thickness of the gas barrier film used in the present invention can be appropriately selected from 12 .mu.m to 100 .mu.m depending on the application. Also,
Commercially available gas barrier films may also be used.

In the composite film of the present invention, a plastisol composition containing blocks of diisocyanate polymers as described above is applied to the surface of the gas barrier film, and then heated to melt and solidify on the surface at a temperature below or above the dissociation temperature of the blocks. By this, a gelled layer of polyvinyl chloride is formed which firmly adheres to the gas barrier film surface of the base material.

The plastisol composition may be applied by various methods such as reverse roll, knife coater, and dip coating.

〔Effect of the invention〕

In the composite film obtained as described above, the vinyl chloride resin thin film is well adhered without impairing the gas barrier properties of the stretched polyvinyl alcohol film, and the film is made of nitrile rubber, butyl rubber, etc. It can be easily composited by heat-pressing molding with a different material that is compatible with vinyl chloride resin, and welder bonding can be used to bond the composite films together. Moreover, the vinyl chloride resin thin film can have a thickness of several microns to 100 microns, and can be made lightweight, making it an extremely useful material in industry.

〔Example〕

Next, the composite film of the present invention will be explained in detail using Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example 1.2 Axial oriented polyvinyl alcohol film (1 degree 900, degree of saponification 99%, stretching ratio 3 x 3, film thickness 14μ)
and a biaxially oriented ethylene-vinyl acetate copolymer saponified resin film (ethylene content 29%, degree of saponification 99%, stretching ratio 3 x 3, film thickness 14 μm) with the following composition on each side surface. Polyvinyl chloride plastisol was applied to a film thickness of 20 μm, heated and melted in a gear oven at 130° C. for 2 minutes, and cooled to solidify to form a film.

Composition: After dispersing the rubber compound with the following composition,
This was applied to both sides of the two types of composite films 1 and vulcanized for 20 minutes at 150°C in a concave press mold, and at the same time, heated and pressure molded to form the composite film 1 as shown in Figure 1. A molded article (thickness: 2 mm) having a cross-sectional structure having rubber layers 2 on both sides was obtained.

Rubber compounding comparative example 1 In place of the biaxially oriented polyvinyl alcohol used in Example 1, an ethylene-vinyl acetate copolymer film (ethylene content 29%, stretching ratio 3 x 3 times) 14μ thick was used in Example 1. Heat and pressure molding was performed in the same manner as above.

The oxygen permeability and peel strength after welder bonding of the samples prepared in Example 1.2 and Comparative Example 1 were measured.

The results are shown in Table 1.

The oxygen permeation measuring device is 0X-TRAN 100A (Mlo
oA (C0NTR0LS, manufactured by INC). (A
STM: D3985-81) The welder adhesion processing method is as follows: High frequency welder equipment, model KL2-1 manufactured by Nippon Koshuha ■
000 adhesive electrode bar 2K for 2 seconds on 3 cylinders in 50m length
Adhesive processing was performed using G load.

The peel strength was determined by cutting the sample to be measured into a size of 15 mm x 200 nun so that the welder bonded part was approximately in the middle position, and peeling was performed at 180 degrees at a tensile speed of 100 mn+/min using an autograph (IM-100 manufactured by Shimadzu).

Table 1 Oxygen permeability Peel strength Example 1 0.2 cc/nr 24hrs atm
620g/15mm Example 2 0.28 cc/r
rf 24hrs atm 620g10.5mm
Comparative example 1 4.5 cc/rf 24hrs atm
Example 3 A polyvinyl chloride plastisol having the following composition was applied to the polyvinyl alcohol film used in Example 1, and
The material was heated and melted at 150° C. for 2 minutes with the gear open, and then cooled and solidified to create a vinyl chloride resin film with a thickness of 20 μm.

Vinyl chloride base resin P-540 (manufactured by Mitsubishi Kasei Vinyl ■) 100 parts by weight trioctyl trimellitate 20 Epoxidized soybean oil 3 Lead-based stabilizer
2 33x1) BP solution of oxybenzoic acid ester of TDI trimer 15 The vinyl chloride resin films of the above laminate film were brought into close contact with each other and welder bonding was performed using a high frequency welder, and the peel strength of the bonded portion was measured.

Comparative Example 2 A laminate film was created by laminating a 70 μ thick soft vinyl chloride resin film (DOP 40 parts) to the base material used in Example 1 using a thermosetting two-component polyurethane resin adhesive (10 g/rn dry). did. The sample was subjected to welder bonding processing in the same manner as in Example 1, and the peel strength of the bonded portion was measured.

Table 2 shows the results of Example 3 and Comparative Example 2.

Table 2 Oxygen permeability Peel strength Example 3 0.3 cc/n? 24hrs atm
490g/15mm Comparative Example 2 Same as above
215 g/15 mm In both Example 3 and Comparative Example 2, peeling occurred at the adhesive interface between the polyvinyl alcohol layer and the vinyl chloride resin layer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a molded product using the composite film of the present invention, and is a schematic enlarged view of the layer structure. FIG. 2 is a plan view thereof. 1... Composite film layer of the present invention 2... NBR rubber layer

Claims (1)

[Claims] 1. A coating layer made of a polyvinyl chloride polymer plastisol composition containing an adhesion imparting agent is formed on both surfaces of a gas barrier film, and the coating layer is heat-treated to gel and form an adhesive film. composite film.