JPH0615225B2 - STRUCTURAL MEMBRANE MATERIAL, MEMBRANE STRUCTURE, AND METHOD FOR PRODUCING THEM - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is excellent in weather resistance, antifouling property, flexibility, low flammability, and airtightness, and is particularly useful for air dome, warehouse, flexible container, automobile, large machine, etc. The present invention relates to a film-like structure composed of a structural film material using a fluororesin having flexibility suitable for a cover and a bonded product thereof, and a method for producing these.

[Prior art]

As a structural membrane material for an air dome, some fluororesins such as glass fiber cloth coated with polytetrafluoroethylene (PTFE) have begun to be used. In order to increase the area of these film productions, heat welding is performed with a tape of tetrafluororetien (TFE) -hexafluoropropene (HFP) copolymer resin (FEP) interposed, and further bonding strength is required. In the case of the use, sewing is also used together.

In addition, a fluorine-based polymer [PTFE, polyvinyl fluoride (P
VF), polyvinylidene fluoride (PVDF), etc.] to form a film body, and the film bodies are heat-welded together via a band-shaped film (JP-A-60-125637).
Further, a synthetic fiber-based coarse-density woven fabric is used as an interlining material, and a soft vinyl chloride sheet having soft vinyl chloride resin coatings formed on both sides of the soft vinyl chloride sheet surface is covered with a thin laminated film of PVDF and acrylic resin so that the VDF layer becomes the uppermost layer. The fusion-integrated sheet is interposed with a polymethylmethacryl (PMMA) film, or a solution type acrylic resin is applied to a portion to be adhered of the sheet and dried with hot air or the like, and then the sheets are heated, A method of pressure welding (JP-A-60-52328) is known.

[Problems to be solved by the invention]

Fluororesin, which has been known as a conventional structural film material, has excellent heat resistance, weather resistance, airtightness, etc., but lacks flexibility and processability, and when used as the top layer of a structural film material, changes in temperature change. If it has been used for many years because it cannot follow the condition, layer peeling occurs with the base material of the structural film material, cracks due to falling objects, whitening or wrinkles generated during construction remain as is. was there.

Further, the fluororesin layer is inert and extremely stable thermally and chemically, but in order to obtain the bonding strength required as a structural film material, the bonding process only by heating is insufficient,
I had no choice but to use sewing etc. together.

The present invention was devised in order to overcome the above-mentioned drawbacks of the prior art, and is a structural film material having weather resistance, antifouling property, flexibility, low flammability, and airtightness and sufficient mechanical properties. The present invention provides a laminated body as a structural film material bonded with strength and durability, a manufacturing method thereof, and a film-like structure using the same and a manufacturing method thereof.

[Means for solving problems]

One of the means for solving the above problems is one or more kinds of monomers containing at least one kind of fluorine-containing monomer, and a monomer having a double bond and a peroxy bond at the same time in the molecule. By copolymerizing with a monomer, a fluorine-containing elastic copolymer (trunk polymer) containing a peroxy group in its molecule and having a glass transition temperature at room temperature is produced.
A soft fluororesin obtained by graft-polymerizing 20 to 80 parts by weight of a vinylidene fluoride monomer with respect to 100 parts by weight is used as a structural film material.

The present inventors have disclosed a method for producing this soft fluororesin, which is disclosed in Japanese Examined Patent Publication No. 62-34324, but as the soft fluororesin used as a structural film material and a film-like structure intended by the present invention, From studies of solubility, weather resistance, antifouling property, etc., it is suitable to use a graft copolymer of vinylidene fluoride on a trunk polymer, and the ratio is 20% vinylidene fluoride monomer per 100 parts by weight of the trunk polymer. It is preferable that the graft polymerization of ˜80 parts by weight is carried out.

If the amount of vinylidene fluoride is less than this range, the strength of the coating obtained by coating or melt molding will be weak and there will be the inconvenience of breaking during bending, and if it is more than this range, the desired flexibility of the coating will be lost.

Unsaturated peroxides used here include unsaturated peroxyesters such as t-butylperoxymethacrylate and t-butylperoxycrotonate, and unsaturated peroxycarbonates such as t-butylperoxyallylcarbonate and P-menthane peroxyallylcarbonate. Can be illustrated.

The composition of one or more of the fluorine-containing monomers is an elastic polymer having a composition of fluororubber, which is a binary system of vinylidene fluoride (VDF) and hexafluoropropene (HFP), VDF, HFP and tetrafluoro. Ethylene (TF
Examples thereof include ternary systems of E) and binary systems of VDF and chlorotrifluoroethylene (CTFE).

By using the resin as a top layer of turboline composed of a combination of polyester fiber cloth and soft vinyl chloride resin, the general properties required for the structural film are weather resistance, antifouling property, flexibility and anti-wrinkle property. A structural film material satisfying all the properties, low flammability and secondary workability such as welding and adhesion can be obtained.

In the accelerated exposure test with a sunshine weatherometer, the soft fluororesin has a good retention of tensile properties (breaking strength, elongation) of 90% or more even after 5000 hours, and the transparency of the film hardly changes. The Shore-D hardness, which is a measure of flexibility, is 40 to 55, and PTFE (55 to 65), PVDF, which is a conventionally known general fluororesin, and PVDF are used.
It is much more flexible than (80) and is a material with excellent impact resistance and flex resistance. Further, the resin has a melting point of about 165 ° C, a low temperature use limit (brittleness temperature) minus 55 ° C,
On the high temperature side, in a long-term exposure test at 150 ° C in a gear oven, properties such as flexibility and tensile properties hardly change even after 10,000 hours, and thermal deterioration hardly occurs.

As the turbo link loss used in the present invention, the tensile strength is
A polyester fiber cloth of 80 kg / 3 cm or more is suitable,
Polyester cloth has excellent wrinkle resistance, bending recovery, mold retention, dimensional stability, high tensile resistance, and excellent weather resistance. This fiber also has the property of being easily compatible with other resins. Further, as a resin for making the polyester fiber cloth waterproof, it is preferable to use a soft vinyl chloride resin in consideration of flexibility, processability, economy and the like.

As a method for producing the polyester fiber cloth-soft vinyl chloride resin tarpaulin, the polyester fiber cloth is dipped in a soft vinyl chloride resin paste, pulled up and dried,
Depending on the purpose, a method of applying pressure or a method of adhering a film obtained by calender molding of a soft vinyl chloride resin to both surfaces of the polyester fiber cloth can be used. The tarpaulins produced by these methods are used for various purposes, and although they are easily available on the market, these tarpaulins are used as structural film materials such as tents and film-like structures using the same. When used as, the strength of the vinyl chloride resin is reduced due to the deterioration of the weather resistance of the resin during use, migration of the plasticizer to the surface of the sheet, deterioration of aesthetics due to adhesion of dust, generation of mold, etc. are observed. However, it is insufficient as a film material. The present invention solves the above-mentioned drawbacks by forming a film of the above-mentioned soft fluororesin on these tarpaulins. As the film, the soft fluororesin is directly extruded or dimethylformamide (DMF) is mainly used. A film having a thickness of 0.5 to 300 μm, which is obtained by spreading a solution of 5 to 30% by weight dissolved in a solvent on a release paper and drying it, is used. The resin film can also be obtained by a method in which a solution containing a soft fluororesin DMF as a main component is directly coated on a substrate and dried. When the film thickness is 0.5 μm or less, the exudation of the plasticizer from the soft vinyl chloride resin cannot be sufficiently prevented, and the desired antifouling property is difficult to be exhibited. Further, when it is 300 μ or more, it is not suitable from the economical point of view.

One of the features of the polyester fiber cloth-soft vinyl chloride resin tarpaulin of the present invention is ease of bonding. That is, the tarpaulin has an advantage that both hot air pressure welding and welding by a high frequency welder can be performed as they are without applying a new adhesive agent or using an adhesive tape in the joining.

In the present invention, when a soft fluororesin film is laminated on the surface of the tarpaulin, PVF or PV which is conventionally known in that the above-mentioned bonding characteristics can be maintained.
This is a point that is greatly different from the structural film material in which the DF film is laminated.

That is, in the conventional hot-air pressure welding method, it is necessary that the resins on the front surface and the back surface of the laminated sheet melt at the same temperature and have a compatibility capable of expressing sufficient adhesive strength. Further, when the surface coating is thin, the adhesive layer between the surface coating and the tarpaulin also participates in this welding, so it is necessary that the resin on the back surface and the resin in the adhesive layer be the same or have good compatibility. .

The high-frequency welder welding method is a useful welding method in which the width of the joint can be freely changed or curved welding can be performed according to the desired strength, but in general, a fluororesin has a small dielectric loss tangent and a high frequency. It is known that welding by a high-frequency welder is difficult because the amount of heat generated by the welding is small, and even if it is possible, the bonding strength is low.

The present inventors have studied various fluororesins and found that the soft fluororesin used in the present invention is ASTM D150.
The dielectric loss tangent value at 10 ⁶ Hz was 0.28 and PVD
It was found to be superior to 0.16 of F and 2 × 10 ^{5 of} PTFE and excellent in high frequency welding characteristics. It is known that, with respect to the conventionally proposed combination of PVF film and tarpaulin, any welding method is difficult because the melting temperature and the decomposition temperature of PVF are close to each other.

Based on the above facts, various studies were conducted on the back surface resin of the laminated sheet and the adhesive layer resin between the soft fluororesin film and the tarpaulin that satisfy the welding performance, and as a result, PMMA
The inventors have found that only a system adhesive gives the structural film material, and further the adhesive strength and the bonding strength required for a film-like structure using the structural film material. The PMMA-based resin is one which is sufficiently melted at a melting temperature of the soft fluororesin of 180 to 220 ° C. and has compatibility with both the soft fluororesin and the vinyl chloride resin.

Methyl methacrylate resins useful in the present invention include methyl methacrylate homopolymers and copolymers of methyl methacrylate and other unsaturated monomers (preferably copolymerization ratios of other unsaturated monomers. Is 25 mol% or less), and examples of the copolymerizable monomer include methyl acrylate, methyl (meth) acrylate, propyl (meth) acrylate, and (meth).
Examples thereof include butyl acrylate, cyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic glycisol, styrene, α-methylstyrene, and methacrylic acid.

Also, commercially available modified PMMA adhesives can be used, and examples of modified PMMA-based resins include those having an amino group introduced into the side chain and those having an ethyleneimine structure. A thin film of PMMA-based resin can be produced by coating a tarpaulin surface in the form of an organic solvent solution having a solid content concentration of 30 to 40% and drying. It is sufficient that the thickness of these adhesive layers is several μ.

The economical production method of the structural film material of the present invention is to apply a thin coating of PMMA adhesive on both sides of the tarpaulin, dry it, and then coat one side of it with a DMF solution of a soft fluororesin and dry it.

The thus produced laminated sheet has improved adhesiveness, antifouling property, volatility of the plasticizer on the sheet surface due to the plasticizer bleed of the soft vinyl chloride resin, and is imparted with water / oil repellency and stain resistance. .

Further, the adhesive strength between the tarpaulin and the soft fluororesin film of the laminated sheet has sufficient strength as a structural film material, and the welding strength of the laminated sheet is obtained by hot air pressure welding or high frequency welder welding. Even if it is adopted, it is higher than the adhesive strength between the tarpaulin and the soft fluororesin, and sufficient strength can be obtained. There is no restriction on the shape and width of joint welding of sheets at the same time, and it is far superior to the conventionally proposed method of heat welding through a tape-shaped film or the method of applying an adhesive to the joining point. ing.

The present invention is described in detail below with reference to examples, but the present invention is not limited thereto.

Example 1 (A) Production of Trunk Polymer To a 30-volume stainless steel oclave were added 15 kg of water, 30 g of potassium persulfate, 40 g of ammonium perfluorooctanoate and 30 g of t-butylperoxyallyl carbonate, and after evacuation a vinylidene fluoride monomer. Charge 3.8 kg and 2.3 kg of chlorotrifluoroethylene monomer, and stir 5
Polymerization reaction is performed at a temperature of 1 ° C. for 19 hours, and at the end of the reaction, the number of rotations of stirring is increased to precipitate the polymer,
A powdery polymer was obtained. The yield after washing and drying is 5.
At 0 kg, the amount of active oxygen based on t-butylheroxyallyl carbonate in the copolymer was determined by iodometric titration.
It was measured as 0.041%.

(B) Production of graft polymer 144 g of the trunk polymer obtained by the above copolymerization reaction and Freon R1
13 1500 g was charged into a 2-volume stainless steel autoclave, and after evacuation, 100 g of vinylidene fluoride monomer was charged and 98 ° C.
Graft polymerization was carried out for 22 hours. The generated polymer is separated from the solvent, washed with water, and dried to give a white powder of soft fluororesin.
224 g was obtained. The melting point of this polymer was measured by DSC to be 167 ° C. Also, the sheet-shaped molded product obtained by kneading this polymer with a two-roll mill heated to 170 ° C is compressed (temperature
A sheet of 2 mm thick and 160 mm square was prepared at 200 ° C. and a pressure of 80 kgf / cm ² ). The Shore D hardness of this sheet was 50.

(C) Dissolution of soft fluororesin 45 g of soft fluororesin obtained by the above graft polymerization was added to 500 ml.
Into a stainless steel beaker, add 255 g of NN-dimethylformamide (DMF) and stir for 1 hour with TK homodisper manufactured by Tokushu Kika Kogyo Co., Ltd. while not heating to 50 ° C.
After that, it is cooled to room temperature by allowing it to cool, and the soft fluororesin D
An MF solution was obtained.

The viscosity of this solution at 25 ° C. was measured with a B-type viscometer to be 3000 cp.

(D) Manufacture of laminated sheet Composite tarpaulin of polyester fiber cloth and soft vinyl chloride resin (Kuraray Co., Ltd. product number E-5 thickness about 500μ)
Both sides of PMMA adhesive (Sony Chemical
Co., Ltd. product number SC-462, solid content concentration 29-31%, viscosity 30
0 cp (25 ° C.)) was thinly coated, and the solvent was volatilized at room temperature to form an adhesive layer having a thickness of 2 to 3 μm.

Next, the soft fluororesin solution produced in (C) was coated. As for the coating method, the solution was applied on a tarpaulin, the thickness was adjusted with an applicator, and the coating was dried in an oven at 100 ° C. for 5 minutes to obtain a film having a thickness of about 20 μm.

(E) Bonding and Adhesion Test of Sheets by High Frequency Welder The sheets are stacked and a flat electrode of 3 mm × 300 mm is used, and the output adjustment scale is 40 by a high frequency welder (KV-3000TD manufactured by Seidensha Electronics Co., Ltd.). Welding was performed for 5 seconds. Then, a 25 × 125 mm test piece was cut from the welded sheet so that the welded portion was located at the center in the longitudinal direction, and a tensile tester was used to remove 23
A tensile test was performed at a temperature of 50 mm / min. The tensile breaking load was measured as 82kg / 25mm and the tensile breaking load of E-5 itself was 109k.
It showed about 75% of g / 25 mm. The fracture points in this test were the interface between the soft fluororesin and the PMMA adhesive layer and PM.
Since it is the interface of the MA-based adhesive layer, the value of the above breaking load means that the adhesive force of these layers is substantially measured, and it can be said that the bonding strength of the portion welded by the high frequency welder is higher than that.

(F) A sheet manufactured in the stain resistance test (D) and a 100 mm square test piece of E-5 manufactured by Kuraray Co., Ltd. were put in a ball mill together with a dirt substance having the following composition, mixed at room temperature for one week, and then taken out. When the stain degree after washing with water was evaluated on a scale of 5, the results shown in Table 1 were obtained.
The antifouling property of the sheet produced in (D) was clear.

<Fouling substance composition> wt% Peat moss 40 Cement 24 Clay 24 Carbon black 1.5 Iron oxide 0.5 Liquid paraffin 10 Example 2 (a) Preparation of soft fluororesin solution The soft fluororesin solution produced in (A) to (C) of Example 1
By weight of methyl ethyl ketone (MEK) was added to adjust the viscosity at 25 ° C. on a B type viscometer to about 1000 cp.

(B) Manufacture of laminated sheet PMMA adhesive (Nippon Shokubai Co., Ltd., product number Polyment) on one side of a composite tarpaulin (made by Toray Industries, Inc .: product number T-8000, thickness about 600μ) of polyester cloth and soft vinyl chloride resin NK350] a solid content concentration of 35% and a viscosity of 500 cp (25 ° C.)] were thinly coated by a gravure printing method, and the solvent was volatilized at 50 to 60 ° C. to form an adhesive layer having a thickness of 2 to 3 μm. Next to
The soft fluororesin solution prepared in (a) was coated on the adhesive layer by the same method and then passed through a drying oven at 140 to 150 ° C. to form a soft fluororesin film having a thickness of 5 to 6 μm.
After that, a PMMA adhesive was gravure-printed on the other surface to obtain a target laminated sheet.

(C) Adhesion measurement of soft fluororesin film The result of the cellophane tape peeling test specified in JIS D0202 Eye contact test method is 100/100, and the adhesion of soft fluororesin film and tarpaulin is good. Met.

(D) Joining of laminated sheets The sheets produced in (b) are overlapped with a width of about 30 mm, and hot air (220 to 250 ° C) is applied to the inside of the overlapped sheets using a hot air welding machine (Karl Leister Leister 1A type). ), The sheets were joined together by pressure bonding with a hand roller.

(E) Properties of the bonded sheet When a tensile test was conducted on the bonded part by the same method as shown in (E) of Example 1, the tensile breaking load was measured to be 78 kg / 25 mm. On the other hand, T made by Toray Co., Ltd. joined in the same way as (d)
The joint strength of the -8000 sheet was 88 kg / 25 mm, and there was no significant difference between the two.

(F) Sheets manufactured in the outdoor exposure test (b) and Tray manufactured by Toray Industries Inc. as a comparative example
When -8000 was held vertically and exposed outdoors, the surface condition was observed 6 months later. As a result, although the soft fluororesin surface had dust on it, it was easy to remove it by washing with water. On the other hand, the surface of the vinyl chloride resin is roughened, and brown streak-like stains are attached, and the stains on the resin surface cannot be removed even by washing with water. It was revealed that the stain resistance was excellent.

Comparative Example 1 A PVDF composite film (manufactured by Kureha Chemical Co., Ltd.), which is commercially available as a film for imparting antifouling property and weather resistance, on the surface of tarpaulin (T-8000) manufactured by Toray Industries, Inc. used in Example 2 Product number ST-50Y. Thickness about 50μ) 180-190 by press molding machine
Thermal welding was performed at a temperature of ° C and a pressure of 10 kgf / cm ² . The back side is PM
A MA-based adhesive SC-462 was thinly coated and the solvent was volatilized at room temperature to form an adhesive layer having a thickness of 2 to 3 μm.

This laminated sheet was tried to be joined by a high-frequency welder by the same method as shown in (E) of Example 1, but even if the conditions of the high-frequency welder were variously changed, one having sufficient joining strength was not obtained.

Furthermore, the wrinkle resistance of the laminated sheet obtained above and the laminated sheet obtained in Example 2 was measured by the wire method defined in JIS L1096 (23 ° C., untreated). The results are shown in Table 2.

As a result, it is clear that the structural membrane material according to the present invention is superior in high-frequency welding property and anti-wrinkle property as compared with the conventionally proposed laminate of a hard soft fluororesin film such as PVDF.

Comparative Example 2 (A) Production of Soft Fluorine Resin without Graft Polymerization 5 kg of water, 10 g of potassium persulfate and 10 g of ammonium perfluorooctanoate were added to 10 parts of stainless steel oclave, and after exhaustion, 2400 g of vinylidene fluoride monomer, Charge 598g of chlorotrifluoroethylene monomer and stir 48
Polymerization reaction was carried out at a temperature of ° C for 14 hours to obtain a milky white latex. This latex was salted out, filtered, washed and dried to obtain 2.6 kg of a white powder. The melting point of this polymer is 11 by DSC.
It was measured to be 9 ° C. A sheet-shaped molded product obtained by kneading this polymer with two rolls heated to 120 ° C was compression-molded (temperature 140 ° C, pressure 80 kgf / cm ² ) to obtain 2 mm thickness × 160 mm × 16
A 0 mm sheet was produced. The Shore D hardness of this sheet was 53. It had almost the same flexibility as the soft fluororesin in Example 1.

(B) Dissolution The polymer was dissolved in DMF in the same manner as in (C) of Example 1. The viscosity of this solution at 25 ° C is B
It was measured as 5100 cps with a Brookfield viscometer.

(C) Production of Laminated Sheet A laminated sheet was produced by the same method as shown in (D) of Example 1.

(D) Bonding Test and Adhesion Test of Sheet Using High-Frequency Welder The sheet was subjected to high-frequency welding by the same method as shown in (E) of Example 1. The condition of the high frequency welder is the first embodiment.
Under the same conditions as above, sufficient welding strength could not be obtained, so that the output adjustment scale 50 was used for 8 seconds.

A tensile test was carried out by the method shown in (E) of Example 1 at 80 ° C. in consideration of use at room temperature and outdoors. The result is the third
As shown in the table, the difference from Example 1 is clear, and it can be seen that the graft copolymer proposed by the present invention is excellent as the soft fluororesin.

[Effects of the Invention] The structural film material of the present invention and a film-like structure using the same are
Since it is configured as described above, sufficient film bonding strength can be obtained by direct hot air welding or high frequency welding without using an adhesive tape or welding rod as in the past, which simplifies construction It greatly contributes to the increase in area.

Also, because soft fluororesin is used as the surface material,
It has excellent antifouling properties, weather resistance, transparency, anti-wrinkle properties, low flammability, and airtightness, and does not cause peeling or cracking between layers. Further, the structured film material of the present invention has a feature that it can be mass-produced at high speed by the above-mentioned integrated production system.

Claims (5)

[Claims] 1. A structural film material in which a PMMA adhesive layer is provided on both sides of a tarpaulin coated with soft vinyl chloride on both sides of a polyester fiber cloth, and a soft fluororesin is laminated on one side thereof. 2. One or more kinds of monomers containing at least one kind of fluorine-containing monomer and a monomer having a double bond and a peroxy bond at the same time in the molecule are copolymerized to form an intramolecular compound. 2. A soft fluororesin obtained by producing a trunk polymer comprising a fluorine-containing copolymer having a peroxy group and a glass transition temperature of room temperature or lower, and vinylidene fluoride being graft-polymerized on the trunk polymer. Structural membrane material. 3. A polyester fiber cloth is dipped in a soft vinyl chloride resin paste, pulled up and dried to produce a tarpaulin, a PMMA adhesive is applied to both surfaces of the tarpaulin and dried, and a solution containing a soft fluororesin on one surface thereof. A method for manufacturing a structured film material, which comprises: 4. A film-like structure obtained by heat-sealing a plurality of the structure film materials according to claim 1. 5. A method for producing a film-like structure, comprising joining and welding a plurality of structural film materials produced by the method according to claim 3 by means of a high-frequency welder.