JPH07329251A - Membrane structure material and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] A film that imparts hydrophilicity to the film structure material of the air film structure or tension structure used for the roof of a building to make the film surface wet easily and prevent water droplets adhering to the surface from falling. Providing structural materials. [Structure] Membrane base material such as inorganic fiber or heat-resistant organic synthetic fiber is impregnated with or coated with a fluororesin, and the surface of the base material is swelled with a polymer having a hydrophilic group in the molecule, particularly polyvinyl alcohol. A membrane structure material provided with a hydrophilic layer composed of a silicate, and a hydrophilic property obtained by applying an aqueous solution of the above-mentioned polymer having a hydrophilic group and a swelling silicate to the surface of the membrane substrate and removing water from the coating film. A method for manufacturing a membrane structure material having a layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane structure material, and more specifically to a membrane structure material having an affinity for water, suitable for an air membrane structure and a tension structure, and used for the inner surface of a building, and its manufacture. It is about the method.

[0002]

2. Description of the Related Art In recent years, pools, baseball fields, gymnasiums and factories,
For roofs of buildings such as arcades, (1) small roof weight (2) large span (3) translucency (4) construction period is short, so air film structure and tension structure Is used.

As these membrane structure materials, cloths made of inorganic fibers such as glass fibers or heat-resistant organic synthetic fibers coated with a resin having excellent weather resistance and antifouling property are used. A typical resin for coating is a fluorine-containing resin such as polytetrafluoroethylene (hereinafter referred to as PTFE). For example, in Japanese Examined Patent Publication No. 55-7148, there is a silicone resin layer, PTFE on the surface of a glass fiber cloth.
A layer and a glass bead-containing PTFE layer are sequentially formed.

Many of these coating resins are hydrophobic because they require weather resistance and antifouling properties on their coated surfaces. For this reason, it has been pointed out that water drops are formed on the ceiling and the like in the building where the membrane structure material is used to easily cause dew condensation, and the water drops drop downward due to air vibration such as cheering of the audience. In particular,
This problem is remarkable in the membrane structure material coated with the fluorine-containing resin, which is considered to be an optimum material for this application because of its excellent weather resistance, and improvement is desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to impart hydrophilicity to a film structure material while maintaining the properties of the film structure material such as weather resistance, antifouling property and translucency. It is to provide a membrane structure material in which water droplets are prevented from becoming large on the surface of the membrane structure material by making it easy to wet and the hydrophilicity thereof is stably maintained for a long period of time. Another object of the present invention is to provide a manufacturing method in which a hydrophilic membrane structure material can be obtained by a simple treatment such as coating or drying, and further hydrophilic treatment or repair is possible even after the construction of the membrane structure. .

[0006]

Means for Solving the Problems As a result of studying a method for solving the above-mentioned problems, the inventor has found that by providing a layer in which a specific silicate is mixed with a hydrophilic polymer on the surface of a membrane substrate, the hydrophilic property is improved. It has been found that a film structure material having an improved is obtained.

That is, the present invention provides a membrane structure material having a hydrophilic layer comprising a polymer having a hydrophilic group in the molecule and a swelling silicate on the surface of a membrane substrate, and a polymer having a hydrophilic group in the molecule and swelling. A method for producing a membrane structural material provided with the hydrophilic layer, which comprises applying an aqueous solution of a water-soluble silicate to the surface of a membrane base material and removing water contained in the coating film.

The present invention will be described in detail below. The polymer used in the present invention are those having a hydrophilic group in the molecule, as its hydrophilic group, -SO ₃ H, -SO _{3
M, -COOM, -NR 3 X,} -COOH, -NH 2,
_{-OH, - (OCH 2 CH 2} ) n -, - COOCH 3 and the like (wherein R: represents a haloalkyl group, M:: alkali metal or -NH _4, X). Specific examples of the polymer having such a hydrophilic group include polyvinyl alcohol, polyethylene oxide, methyl cellulose, polyacrylic acid, polyacrylamide, sodium polyacrylate, polymethacrylic acid, polymethacrylamide, polyhydroxyethylmethacrylate and polyvinyl. Pyrrolidone, polystyrene sulfonic acid, polyvinyl sulfonic acid or sodium salt thereof, and the like, and tetrafluoroethylene / vinyl acetate copolymers, and alkylene oxide adducts of acrylic acid and methacrylic acid can be mentioned. Among these polymers having a hydrophilic group, polyvinyl alcohol is preferable because it is easily dissolved in water to form a film.

Polyvinyl alcohol is obtained by saponifying polyvinyl acetate, and can be usually used as an aqueous solution of about 5 to 30% by weight to form a film. The solubility of polyvinyl alcohol in water is largely controlled by the degree of polymerization and the degree of saponification, particularly the degree of saponification. For example, those having a saponification degree of 88% or less are almost completely dissolved even at room temperature of 20 ° C. Since the solubility greatly decreases with an increase in the degree of saponification, a partially saponified product is more easily dissolved in water, but a saponification degree of about 86 to 98% is suitable for the purpose of the present invention from the viewpoint of the water resistance of the coating. . The solubility of the partially saponified product (88%) is almost unchanged unless it is subjected to an extreme heat treatment of 180 ° C. × 1 h.

When the degree of polymerization is less than 1000, the hydrophilic layer is easily eluted by contacting water after the formation of 350.
When it exceeds 0, the solubility in water is insufficient and the film formation itself becomes difficult. Therefore, 1000 to 3500, particularly 1500 to 2
400 is preferred.

The swelling silicate used in the present invention has a property of absorbing water in the air or immersing it in water and taking it into the intermediate layer in the crystal to swell.
Structurally, it is a phyllosilicate that has a layered structure of two-dimensionally spread SiO ₄ tetrahedra, and other ions are sandwiched between the layers, making it easy to form inorganic compounds and organic compounds between the layers to form intercalation compounds. .

The size of the particles of the swelling silicate is preferably 10 μm or less in average particle diameter, more preferably 5 μm.
m or less. Since the particle size is small, it becomes a colloidal solution (sol) when placed in water. The colloid-forming ability is represented by a thickening effect when added to water. In the present invention, it is preferable that the addition of at least 5% by weight shows a viscosity of 10 ² cp or more.

The swelling silicate used in the present invention is
Since it is a layered compound, it is easily oriented and has a film forming ability. A semitransparent film can be obtained by pouring 3 to 4% sol on a flat plate and slowly drying.

Specifically, smectite, which is a group of minerals constituting fluoromica or clay, can be used. What is smectite? SiO ₄ tetrahedra are connected by sharing the vertices, and two tetrahedral sheets are joined together by ions having octahedral coordination with the remaining vertices facing inward, and a silicate layer and an alkali. Alternatively, it is a layered silicate having an interlayer structure composed of alkaline earth ions and water molecules coordinated with the alkaline earth ions. Fluorine mica also has a structure and chemical composition similar to that of smectite, and the silicate layer and the layers made of ions such as sodium or lithium are alternately layered, and the hydroxyl ion which is the structure water is partially substituted with fluorine ion. In the present invention, synthetic smectite or fluoromica is preferable from the viewpoint of swelling property and color tone.

The mixing ratio of the polymer having a hydrophilic group in the molecule and the swelling silicate is preferably 70/30 to 5/95 by weight ratio, and when the swelling silicate is 30 wt% or less, the water resistance improving effect is obtained. When the heat treatment temperature is low, a film having high water resistance cannot be obtained. If it is 95 wt% or more, the strength of the hydrophilic layer is insufficient.

The thickness of the hydrophilic layer formed on the surface of the membrane structural material is preferably 0.1 to 30 μm, more preferably 0.1.
It is 5 to 10 μm. If the thickness of the hydrophilic layer is thinner than 0.1 μm, the effect of hydrophilization is small, and if it is 30 μm or more, peeling or loss of the film tends to occur when swollen with water.

The membrane substrate used in the present invention is usually a cloth made of inorganic fibers such as glass fibers or heat-resistant organic synthetic fibers coated with a resin, and these are used in buildings such as pools, baseball fields, gymnasiums and factories. It is used for the roof of.

The inorganic fibers or heat-resistant organic synthetic fibers include inorganic fibers such as glass fibers, alumina fibers, boron fibers, boron nitride fibers, silicone carbide fibers and titania fibers, aromatic polyamide fibers, ultra high molecular weight polyethylene fibers, A woven fabric, a non-woven fabric or a knitted body made of an organic fiber such as an aromatic polyester fiber or a composite yarn using two or more kinds of these can be mentioned. Among them, the fiberglass B yarn is preferable because it has excellent strength and heat resistance and is not affected by low temperature and ultraviolet rays.

The type of resin to be coated is not particularly limited, and various types can be used, but fluorine-containing resins such as PTFE are particularly preferable. The preferred fluorine-containing resin is PTFE, but in addition, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / fluoroalkoxy vinyl ether copolymer, polyvinyl fluoride, polyvinylidene fluoride, etc. may be used.

[0020]

The present invention will be described in detail with reference to the following examples. The types of hydrophilic layer forming materials used in Examples and Comparative Examples, the hydrophilic layer forming method, and the water resistance evaluation method thereof are as follows.

(1) Polyvinyl alcohol Polyvinyl alcohol-500 (Reagent manufactured by Wako Pure Chemical Industries, Ltd., polymerization degree about 500, saponification degree 86 to 90%) Polyvinyl alcohol-1500 (same as above, polymerization degree about 1500,
Saponification degree 86-90%) Polyvinyl alcohol-2000 (Same as above, degree of polymerization about 2000,
Saponification degree 98%) Polyvinyl alcohol-3500 (Kuraray Co., Ltd., polymerization degree, about 3500, saponification degree 88%)

(2) Silicate swellable mica: Fluorine mica ME-100 manufactured by Cope Chemical Co., Ltd. Synthetic smectite: SWN and SWF non-swelling mica manufactured by Cope Chemical Co., Ltd. MK-1
00S

(3) Formation of Hydrophilic Layer 100 mm × 100 mm of PTFE-coated tent membrane (FGT-600 manufactured by Chukoh Chemical Industries, Ltd.)
A liquid in which a swelling silicate is dispersed in a polyvinyl alcohol aqueous solution is applied to one surface of each corner sample by a roll. This is placed in a dryer to remove water and form a coating film.

(4) Evaluation of Water Resistance of Hydrophilic Layer A test film sample having a hydrophilic film formed on the surface by the above-mentioned method was applied to a garden water sprinkler (Toyox nozzle, hole diameter 0) from a height of 1.5 m. 12 mm at 3 mm x 445 pieces)
℃ water at a precipitation of 100 mm / min for 10 minutes and then air-dried. From the weight change before and after the shower, the residual weight% of the coating film
Was calculated and evaluated as the water resistance of the hydrophilic layer.

(5) Hydrophilicity evaluation The membrane structural material, which has been tested for water resistance, is immersed in pure water in a 1 L glass beaker up to 80 mm from the lower end and left standing for 60 seconds. This film is pulled up at a speed of 5 mm / sec to wipe off water on the back side of the hydrophilic layer, and the weight (g) of water retained in the hydrophilic layer is measured.

(6) Wettability Evaluation The hydrophilic layer surface evaluated for hydrophilicity was observed, and the affinity of the membrane structural material for water was evaluated in the following three steps. Dry: Almost no water adheres to the surface of the film Semi-hydrophilic film: Water droplets in a smooth water film-like part and water drops are unevenly wet due to water repellency Hydrophilic film: Water Has a smooth water film and has no unevenness due to water repellency

[Examples 1 to 4] Four kinds of polyvinyl alcohol shown in Table 1 were used as the polymer having a hydrophilic group,
A solution prepared by mixing an aqueous solution containing 10% by weight of this and a colloidal solution containing 10% by weight of swelling mica (ME-100 manufactured by Corp Chemical) at the ratio shown in Table 1
A FE-coated tent film (FGT-600 manufactured by Chukoh Chemical Industry Co., Ltd.) was roller-coated to form a hydrophilic layer on the PTFE. This hydrophilic layer was heat-treated at 50 ° C. for 30 minutes to immobilize it on the tent membrane. With respect to the tent membrane having the hydrophilic layer thus obtained, the hydrophilicity and the water resistance of the hydrophilic layer were evaluated by the methods (4) to (6). The results are shown in Table 1.

[Examples 5 to 9] The same polyvinyl alcohol and swelling mica as those used in Example 3 were used, and the mixing ratio of the two was changed to the ratio shown in Table 1 and mixed in the same manner as in Example 3. The resulting solution was applied to a PTFE-coated tent membrane to immobilize the hydrophilic layer on the tent membrane, and the hydrophilicity and water resistance of the hydrophilic layer were evaluated. The results are shown in Table 1 together with the results of Example 3.

[Examples 10 to 14] A solution prepared by mixing the same polyvinyl alcohol as used in Example 3 and swelling mica in the mixing ratio shown in Table 1 was applied to a PTFE-coated tent membrane to obtain a hydrophilic layer. Was formed on PTFE and then fixed on a tent membrane under a heat treatment condition of 140 ° C. for 30 minutes, and the hydrophilicity and the water resistance of the hydrophilic layer were evaluated. The results are shown in Table 1.

[Examples 15 to 16] Polyvinyl alcohol (polyvinyl alcohol) was used in the same manner as in Example 7 except that synthetic smectite (SWN and SWF manufactured by Cope Chemical Co., Ltd.) was used instead of mica ME-100 as the swelling silicate. The solution mixed with Alcohol-2000) is applied to the PTFE-coated tent membrane to make the hydrophilic layer PT.
After being formed on FE, it was heat-treated at 50 ° C. for 30 minutes to be immobilized on the tent membrane, and the hydrophilicity and the water resistance of the hydrophilic layer were evaluated. The results are shown in Table 1.

[Comparative Examples 1 to 4] A PTFE coated tent membrane (FGT-manufactured by Chukoh Chemical Industries, Ltd.) was prepared in the same manner as in Examples except that an aqueous solution containing 10% by weight of polyvinyl alcohol was used without adding a swelling silicate. 600) was coated with a roller to form a polyvinyl alcohol layer on the PTFE. This was immobilized on a tent membrane under the heat treatment conditions shown in Table 1 to evaluate hydrophilicity and water resistance of the hydrophilic layer. The results are shown in Table 2.

Comparative Example 5 Only a colloidal solution containing 10% by weight of swelling mica (ME-100 manufactured by Corp Chemical) was roller-coated on a PTFE-coated tent film to form a layer of swelling mica on PTFE. did. This one
After heat treatment at 40 ° C. for 30 minutes to immobilize it on the tent membrane, hydrophilicity and water resistance of the hydrophilic layer were evaluated. The results are shown in Table 2.

[Comparative Example 6] In Example 7, instead of the swelling mica, a non-swelling mica (MK-1 manufactured by Corp Chemical) was used.
00S) was used, and PTF was prepared in the same manner as in Example 7.
E Coating tent film is roller coated and the coating layer is PT
Formed on FE. This was heat-treated at 50 ° C. for 30 minutes to be immobilized on the tent membrane, and the hydrophilicity and the water resistance of the hydrophilic layer were evaluated. The results are shown in Table 1.

[Comparative Examples 7 to 8] The PTFE coating tent membrane (FGT-600 manufactured by Chukoh Kasei Kogyo Co., Ltd.) and the glass plate used as the membrane base material in the Examples were not subjected to hydrophilic treatment, but were hydrophilic as they were. Was evaluated. The results are shown in Table 1.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

INDUSTRIAL APPLICABILITY The membrane structure material of the present invention has an excellent affinity for water as compared with the conventional membrane structure material, and the condensed water on the membrane surface becomes a thin water film and is retained on the membrane or along the membrane. Can flow down. Therefore, it is suitable for a building that does not want to drop water drops due to dew condensation on the inner surface of the membrane structure, especially on the ceiling.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location D06M 15/333 E04H 15/54 // C09D 127/12

Claims (6)

[Claims] 1. A membrane structure material having a hydrophilic layer comprising a polymer having a hydrophilic group in the molecule and a swelling silicate on the surface of the membrane substrate. 2. The membrane structure material according to claim 1, wherein the weight ratio of the polymer having a hydrophilic group in the molecule to the swelling silicate is 70/30 to 5/95. 3. A polymer having a hydrophilic group in the molecule is 100.
The film structure material according to claim 1 or 2, which is polyvinyl alcohol having a degree of polymerization of 0 to 3,500. 4. The membrane structural material according to claim 1, wherein the membrane base material is a base cloth made of inorganic fibers or heat-resistant organic synthetic fibers impregnated with or coated with a fluorine-containing resin. 5. A method comprising applying an aqueous solution containing a polymer having a hydrophilic group in the molecule and a swelling silicate to the surface of a membrane substrate to remove the water content from the coating film. 1. The method for producing a membrane structure material according to 1. 6. Polyvinyl alcohol and average particle size 10
The weight ratio with the swelling silicate having a size of μm or less is 70/30 to 5 /
The method for producing a membrane structure material according to claim 1, wherein an aqueous solution of 95 is applied to the surface of the membrane substrate to remove the water content from the coating film.