JPH0156670B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a composite barrier membrane, and more particularly to a method for producing a composite barrier membrane having a specific surface protection layer and having excellent weather resistance.

As membrane materials for balloons, air membrane structures, etc., there is a desire for membrane materials that have barrier properties and are excellent in mechanical strength and weather resistance. Conventionally, for this purpose, a composite barrier membrane has been proposed in which a reinforcing fiber layer is provided on one side of the barrier material to improve mechanical strength, and a surface protective layer is provided on the other side to provide weather resistance. The surface protective layer has been mainly formed by laminating a polyfluorinated vinyl film onto a barrier material via an adhesive layer.

However, in the conventional method for producing composite membranes, the process is complicated and the weight of the resulting composite membrane is large, as it is essential to interpose an adhesive layer between the surface protection layer/barrier layer. In addition to this, there were other drawbacks such as deterioration of the adhesive layer normally interposed between the barrier layer/reinforcing fiber layer during the formation of the surface protective layer, resulting in loss of weather resistance.

Recognizing the above problems, the present inventors conducted extensive research and found that a reinforcing fiber material was added to a barrier material on which a surface protective layer consisting of a cured coating film of a specific fluorine-containing copolymer was previously formed. It has been found that by employing a laminating method, such problems can be solved and a composite barrier film with excellent weather resistance can be manufactured smoothly.

The present invention has thus been completed based on the above findings, and provides a method for producing a composite barrier membrane having a surface protective layer, a barrier layer and a reinforcing fiber layer, which comprises a unit based on tetrafluoroethylene and an alkyl vinyl ether as the main component, and further comprises: An organic solvent solution containing a curing agent and a fluorine-containing copolymer containing units based on monomers that provide reaction sites at a ratio of 20 mol% or less is applied, and the solvent is volatilized and the coating film is cured. The present invention provides a novel method for manufacturing a composite barrier membrane, which is characterized in that a reinforcing fiber material is laminated on a barrier material on which a surface protective layer has been previously formed by tightening the barrier material.

In the present invention, it is possible to use a fluorine-containing copolymer which has units based on tetrafluoroethylene and alkyl vinyl ether as main components and further contains units based on a monomer that provides a reactive site in a proportion of 20 mol% or less. is important.

Here, the content ratio of units based on tetrafluoroethylene and alkyl vinyl ether in the fluorine-containing copolymer can preferably be in the range of about 70:30 to 30:70 from the viewpoint of weather resistance, flexibility, etc. From the viewpoint of copolymerization properties and coating film properties, preferred alkyl vinyl ether components include those containing a linear, branched or cyclic alkyl group having about 2 to 8 carbon atoms.
As a comonomer that provides a reactive site in such a copolymer, functional group-containing vinyl ethers such as hydroxyalkyl vinyl ether or glycidyl vinyl ether can be preferably employed from the viewpoint of copolymerization properties. The content of units based on comonomers providing reactive sites in the copolymer is 20 mol% or less, preferably about 1 to 15 mol%. If the ratio is too small, curing will be insufficient,
Moreover, if it is too large, the flexibility of the coating film may be impaired, which is disadvantageous.

The above-mentioned copolymers can be produced by causing a copolymerization reaction by causing a polymerization initiator or a polymerization initiation source such as ionizing radiation to act on a monomer mixture of a predetermined ratio in the presence or absence of a polymerization medium. It can be manufactured by

In the present invention, various curing agents that can be included in the coating composition include various polyfunctional compounds that are reactive with the reactive sites of the fluorine-containing copolymer, and curing aids and curing agents. It is also possible to use it in combination with a catalyst. The amount of the curing agent is not particularly limited, but is usually selected appropriately from a range of about 0.1 to 100 parts by weight, particularly about 0.5 to 50 parts by weight, per 100 parts by weight of the copolymer.

The type of curing agent is preferably selected appropriately depending on the type of the reaction site and the curing method. For example, for a fluorine-containing polymer whose reactive site is a hydroxyl group, if the composition is to be cured at room temperature,
Polyisocyanate or titanium alkoxide can be preferably employed as the curing agent. In addition, when the composition is of a heat-curing type, melamine curing agents, urea resin curing agents, polybasic acid curing agents, etc., which are used in ordinary thermosetting acrylic paints, are effective as curing agents. Here, examples of the melamine curing agent include butylated melamine, methylated melamine, epoxy-modified melamine, etc., and various degrees of modification from 0 to 6 can be used depending on the application, and the degree of self-condensation can also be selected as appropriate. be able to. Examples of the urea resin include methylated urea, butylated urea, and the like. Further, as the polybasic acid curing agent, long-chain aliphatic dicarboxylic acids, aromatic polycarboxylic acids or their anhydrides, blocked polyvalent isocyanates, and the like are useful. When using a melamine or urea curing agent, curing can be accelerated by adding an acidic catalyst. As another example, when the reactive site of the fluorine-containing polymer is an epoxy group, amines, carboxylic acids, phenols,
Alcohols and the like are effective as curing agents, and in this case polyhydroxy compounds, especially non-aromatic diols, are useful as curing aids.

In the present invention, various properties such as film durability, aesthetic appearance, and water repellency can be improved by adding various components such as ultraviolet absorbers, colorants, and water-repellent imparting components to the coating composition. It is possible.

The coating composition can be applied by various methods including, but not limited to, brush coating, dip coating, roll coating, flow coating, and spray coating, but from the viewpoint of productivity and uniformity of the coating film, etc. , spray painting and roll coating methods can be preferably employed.

In the present invention, the type of organic solvent, the volatilization of the solvent, and the conditions for curing the coating film are not particularly limited, and are desirably selected depending on the use of the composite film, the curing method, etc. In terms of the relationship between curing conditions and the type of solvent, in the case of room temperature curing or low temperature curing up to about 80℃, low boiling point materials such as xylene, toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and butanol are recommended. In the case of baking at a high temperature such as 120 to 140°C, a high boiling point aromatic solvent or a high boiling point solvent such as cellosolve acetate may be added as appropriate to the above low boiling point, respectively. It can be preferably adopted.

The thickness of the cured coating film thus formed is:
Usually, the range is 5 to 60 μm, preferably 10 to 30 μm. If it is too thin, the protective effect will decrease,
If it is too thick, it is not only uneconomical but also unsuitable for applications that require lightness.

In the present invention, various materials can be used as the barrier material, including those conventionally known or well-known, such as films made of polyethylene terephthalate, saponified ethylene-vinyl acetate copolymer, aromatic polyamide, and even polyacrylonitrile. Illustrated. Further, the reinforcing fiber material is similarly not limited to polyester fibers, aromatic polyamide fibers, etc., and various materials can be employed.

In the present invention, it is important to laminate the reinforcing fiber material onto a barrier material on which a surface protective layer consisting of a cured coating film of a specific fluorine-containing copolymer as described above has been formed. By adopting such a configuration, it becomes easy to form a homogeneous surface protective layer, and the restrictions regarding the curing conditions when forming the surface protective layer based on the heat resistance of the adhesive layer that is normally interposed between the barrier layer/reinforcing fiber layer are removed. It also has the effect of

According to the present invention, it is possible to easily manufacture a composite barrier membrane that has high gas barrier properties, high mechanical strength, and excellent weather resistance, and has particular utility in the field of membrane materials for outdoor use. is extremely large.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 The following coating composition was prepared using a fluorine-containing copolymer containing units based on tetrafluoroethylene, ethyl vinyl ether, and hydroxybutyl ether in proportions of 50 mol%, 35 mol%, and 15 mol%, respectively. did.

Fluorine-containing copolymer 100 parts by weight Melamine resin (Mitsui Toatsu: Cymel 325) 10 Curing catalyst (Same as above: Catalyst 6000) 0.5 Titanium oxide (Ishihara Sangyo: CR-90) 40 Mixed solvent 200 The mixed solvent is methyl ethyl ketone, ethyl acetate, cellosolve acetate, and a high-boiling aromatic solvent (Solbetsuso #150 manufactured by Tonen) in a weight ratio of 1:1:
They were mixed at a ratio of 1:1.

The coating composition obtained above was applied onto a saponified ethylene-vinyl acetate copolymer film (30 μm thick).
Spray paint to a dry film thickness of 20μm,
Bake hardening was performed at 120°C for 40 minutes to form a barrier material with a homogeneous surface protective layer.

Next, aromatic polyamide fiber (DU
Pont: Kevlar) basket woven fabric (160g/m ² )
were laminated to produce a composite barrier membrane.

When the thus obtained composite barrier film was subjected to a 400-hour accelerated weathering test using a due cycle weather meter, it was confirmed that there was almost no deterioration as shown below.

Before test After test [Barrier material/reinforcing fiber material] Adhesive strength (Kg/cm)
2.0 1.7 Helium permeability (cc/ ^m2・24hr・atm)
72 73 On the other hand, in the case of a laminate of barrier material and reinforcing fiber material without the above-mentioned surface layer, accelerated weathering tests using a similar dual cycle weather meter showed that the barrier material deteriorated significantly and the adhesive strength It also became impossible to measure helium permeability.

Example 2 A fluorine-containing copolymer containing units based on tetrafluoroethylene, cyclohexyl vinyl ether, isobutyl vinyl ether, and hydroxybutyl vinyl ether in proportions of 50 mol%, 25 mol%, 15 mol%, and 10 mol%, respectively, was used. , the following coating composition was prepared.

Fluorine-containing copolymer 100 parts by weight Titanium oxide (Ishihara Sangyo: CR-90) 40 Mixed solvent 200 Isocyanate curing agent (Nippon Polyurethane: Coronate EH)
18 〃 Dibutyltin laurylate 0.003 〃 Ultraviolet absorber (manufactured by Ciba Geigy: Tinuvin 327) 10 〃 The mixed solvent is a mixture of methyl ethyl ketone, butyl acetate, cellosolve acetate, and xylene in a weight ratio of 1:1:1:3 It is.

A composite barrier film was produced in the same manner as in Example 1 except that the above coating composition was used and the coating film was cured at room temperature for 7 days.

After a 400-hour accelerated weather test using a due-cycle weather meter, the adhesive strength and helium permeability of the thus obtained composite barrier membrane to [barrier material/reinforcing fiber material] were 1.5 Kg/cm and 85 Kg/cm, respectively.
It was cc/ ^m2 , 24hr, atm.

Claims (1)

[Claims] 1. In a method for producing a composite barrier membrane having a surface protective layer, a barrier layer and a reinforcing fiber layer, the main components are units based on tetrafluoroethylene and alkyl vinyl ether, and the content of units based on monomers that provide reaction sites is 20 mol% or less. By applying an organic solvent solution containing a fluorine-containing copolymer and a curing agent in a ratio of A method for producing a composite barrier membrane characterized by laminating fiber materials.