JPH0524271B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing a waterproof sheet. More specifically, the present invention relates to a method for manufacturing a waterproof sheet in which the fibrous base fabric constituting the waterproof sheet does not have water absorbency. [Prior Art] Conventionally, waterproof sheets have been manufactured by forming a film made of a high molecular weight polymer on the surface of a fibrous base fabric. However, in a waterproof sheet formed by forming a coating on both sides of a fibrous base fabric, if the intermediate layer of fibrous base fabric sandwiched between the coatings cracks or tears even slightly, the crack or tear occurs. There is a drawback that water is absorbed from the sheet or from the cut cross section of the sheet even in the absence of such a phenomenon. If the fibers are dense, this water absorption is further increased by capillary action. And, due to the absorption of water, the tarpaulin not only becomes heavier, but also
This results in a decrease in the adhesion between the fibrous base fabric and the coating. In addition, the absorbed water is difficult to release from the fibrous base fabric, and furthermore, there is a drawback that, for example, it causes the growth of mold, and it absorbs sewage or water with a different color, which impairs the appearance of the sheet. In order to eliminate such drawbacks, it has been conventional practice to treat a fibrous base fabric with a water repellent and then form a polymer coating on both surfaces thereof. In this case, since the fibrous base fabric is treated with a water repellent, water penetration is prevented, but on the other hand, if the water repellent effect is increased, the adhesion between the polymer coating and the water repellent treated fibrous base fabric will be reduced. The adhesive strength of the polymer coating decreases, making it undesirable for practical use. Efforts have also been made to improve adhesion by adding adhesive substances such as isocyanates to water repellents and coating agents, but currently no satisfactory results have been obtained. It is. [Problems to be Solved by the Invention] In view of these current circumstances, the present invention provides a fibrous base fabric with sufficient water repellency while sufficiently increasing the adhesion between the fibrous base fabric and a polymer coating. A method for manufacturing a waterproof sheet is provided. [Means for Solving the Problems and Their Effects] According to the present invention, there is provided a method for manufacturing a waterproof sheet by forming a polymer coating on both sides of a fibrous base fabric. , the fibrous base fabric is first treated with a water repellent, then both surfaces thereof are subjected to a corona discharge treatment, and then a polymer film is formed on both surfaces. The method of the present invention not only significantly improves the adhesive strength between the water repellent layer and the polymer coating, but also significantly improves the adhesive strength between the water repellent agent and the base fabric, and improves the adhesive strength between each layer of the waterproof sheet as a whole. can improve the adhesive strength of Fibrous base fabrics useful in the present invention include natural fibers such as cotton, linen, etc., inorganic fibers such as glass fibers, carbon fibers, asbestos fibers, metal fibers, etc.
Regenerated fibers, such as viscose rayon, cupra, etc., semi-synthetic fibers, such as g- and tri-acetate fibers, and synthetic fibers, such as nylon 6, nylon 66, polyester (polyethylene terephthalate, etc.) fibers, aromatic polyamide fibers, It is made of at least one selected from acrylic fibers, polyvinyl chloride fibers, polyolefin fibers, and insoluble or hardly soluble polyvinyl alcohol fibers. The fibers in the base fabric are short fiber spun yarn, long fiber yarn, split yarn,
It may be in any form such as tape yarn, and the base fabric may be a woven fabric, a knitted fabric, a non-woven fabric, or a composite fabric thereof. In general,
The fibers used in the waterproof sheet of the present invention are preferably polyester fibers and glass fibers, and considering that they have little elongation under stress, these fibers are preferably in the form of long fibers (filaments), and Although it is preferable to form a plain woven fabric, there are no particular limitations on the weaving structure or its form. The fibrous base fabric is useful for maintaining the mechanical strength of the resulting tarpaulin sheet at a high level. These base fabrics are first treated with a water repellent (some of which necessarily exhibit oil repellency) for the purpose of imparting water repellency (water absorption prevention properties). Typical water repellent (oil repellent) agents include, for example, wax, aluminum soap, zirconium salts, quaternary ammonium salts (e.g., stearoylmethylamide methylene pyridinium salt), N-methylol fatty acid amides (e.g., N- methylolstearamide),
Amino resin derivatives (e.g. stearoyl melamine), fluorine compounds (e.g. polyacrylic acid fluorinated alkyl ester), silicones (e.g.
dimethylpolysiloxane) and other known water repellents. These water repellents can be used alone or as a mixture of two or more. Although the treatment with the water repellent can be carried out by impregnation, coating, spraying, or other methods, the impregnation method is simple and effective. The base fabric treated with a water repellent in this manner is dried or, as the case may be, without drying, is subjected to a corona discharge treatment. Corona discharge treatment involves applying a high voltage between a roller that supports the base fabric and an electrode placed opposite it.
A corona discharge is generated, and the surface of the base fabric is sequentially treated while moving the base fabric during that time. The corona discharge treatment can be performed continuously, for example, by running the base fabric at a predetermined speed between a pair of rolled discharge electrodes as shown in FIG. In FIG. 1, a pair of rolled discharge electrodes 1
and 2 each have one metal electrode core 3, 4 and a non-electrically conductive resin layer 5, 6 (for example, a rubber layer) covering it. The electrode core 3 of one roll-shaped discharge electrode is connected to a high-voltage power source 7, and the electrode core 4 of the other roll-shaped electrode is connected to ground 8. The base fabric 10 fed through the guide roll 9 is moved between the discharge electrodes at a constant speed (for example, 2 to 10 m/min) with one side 11 in contact with the circumferential surface of the rolled electrode 2 connected to the ground. Migrate with . At this time, when a predetermined voltage (100 to 200 V) is applied between both rolled electrodes 1 and 2, a corona discharge of 10 to 60 A is generated, and the surface of the base fabric 10 on the base fabric 12 side is treated by this corona discharge. . The distance A between the circumferential surfaces of both electrodes is 30 mm or less, generally 5 ~
It is 20mm. Base fabric 10 subjected to corona discharge treatment
is wound up via a guide roll 13 to form a roll 14. For corona discharge treatment, spark gap method,
Vacuum tube method, solid state method, etc. can be used. In order to improve the adhesion of the water repellent treated base fabric, its critical surface tension should be increased from 35 to
It is preferable to set it to 60 dyn/cm, and for this purpose, it is preferable to apply processing energy of about 5 to 50,000 W/m ² /min, preferably about 150 to 40,000 W/m ² /min to the surface of the base fabric. The amount of energy to be applied (voltage, current amount, distance between electrodes, etc.) is determined in consideration of the width of the base fabric, processing speed, etc. For example, when performing corona discharge treatment on a base fabric surface with a width of 2 m at a processing speed of 10 m/min, the output (power consumption) is preferably about 4 kW to 800 kW. However, it is not necessarily limited to this condition. The corona discharge device used in the method of the invention may be of the usual metal electrode type. The performance of the high-voltage power supply and the like of the corona discharge device can be arbitrarily determined as desired. In the present invention, since the purpose of the waterproof sheet formed by forming a waterproof coating on both sides of a fibrous base fabric is to prevent the fibrous base fabric from absorbing water, the corona discharge treatment is performed on a waterproof sheet formed by forming a waterproof coating on both sides of the fibrous base fabric. It is necessary to perform this on both surfaces of the fibrous base fabric. In the present invention, the corona discharge treatment is performed only on the surface layer of the surface of the base fabric, which significantly improves the adhesion of the fibrous base fabric to the polymer coating via the water repellent layer, which is preferable. It was discovered that it can become a thing. What is important here is that rather than applying corona discharge treatment to the base fabric to improve its adhesion and then treating it with a water repellent, The method of the present invention is characterized by removing the adhesion-inhibiting property of the water repellent. The fabric thus treated is then coated with a high molecular weight polymer on both surfaces thereof. Examples of the high molecular weight polymer include synthetic resin, synthetic rubber, and natural rubber. Preferred synthetic resins include, for example, polyvinyl chloride (PVC), polyurethane, ethylene-vinyl acetate copolymer, isotactic polypropylene, polyethylene, Examples include polyacrylonitrile, polyester, polyamide, fluororesin, silicone resin, and other known materials. Examples of preferable synthetic rubbers include styrene-butadiene rubber (SBR), chlorosulfonated polyethylene rubber, polyurethane rubber, butyl rubber, isoprene rubber, silicone rubber, fluorine rubber, and other known materials. In particular, polyvinyl chloride, fluorine-based and silicone-based rubbers and resins, and acrylic resins are preferred polymers for the present invention. These polymers may contain plasticizers, colorants, various stabilizers, flame retardants, etc., as long as they do not impede the purpose of the present invention. In particular, in order to strengthen the adhesiveness between the fibrous base fabric and the polymer, it is more preferable to interpose an adhesive substance at the interface between the fibrous base fabric and the polymer. Examples of useful adhesives include melamine adhesives, phenolic adhesives, epoxy adhesives, polyester adhesives, polyethyleneimine adhesives, polyisocyanate adhesives, polyurethane adhesives, and acrylic adhesives. Examples include, but are not limited to, copolymer adhesives, silicone adhesives, polyamide adhesives, vinyl acetate-vinyl chloride adhesives, vinyl acetate-ethylene adhesives, etc. Any known adhesive can be selected and used. The adhesive substance may be used by being mixed into the polymer, or may be applied to the interface. The surface coating can be formed by conventional methods such as
This can be carried out by a calendering method, an extrusion method, a coating method, a dipping method, or the like. In addition, the treatment of the present invention can be applied to base fabrics made of inorganic fibers,
Especially when applied to base fabrics made of glass fibers, in addition to the aforementioned effects, there are also disadvantages of glass fiber base fabrics;
In other words, it is possible to overcome the drawback of low bending resistance, such as easy breakage during repeated bending, resulting in a decrease in strength. Therefore, the waterproof sheet obtained by the present invention has the feature that even when an inorganic fiber base fabric is used, it can be used for a long period of time in applications that involve repeated folding, folding, and vibration. [Example] Hereinafter, the present invention will be further explained with reference to Examples. Example 1 and Comparative Examples 1 and 2 Polyester fiber base fabric: 1000 d x 1000 d / 32 pieces / 1 x 32 pieces / 300 g / m ² thickness 0.35 mm was treated with Hobotex as a water repellent under the following conditions.
Treated with FTC (Ciba-Geigy product, amino resin derivative water repellent). Catalyzer RB (manufactured by Ciba-Geigy) was used as a reaction catalyst in a proportion of 25% by weight based on Hobotex FTC. Water repellent concentration (% aqueous solution) 9.0, 4.5, 3.6, 3.0, 2.1,
1.5, 0.9, 0.3 Solid content concentration (%owf) 3.0, 1.5, 1.2, 1.0,
0.7, 0.5, 0.3, 0.1 After immersing the base fabric in water repellent baths of various concentrations, squeezing with a mangle to give a wet adhesion amount of 100 g/ ^m2 , pre-drying at 80 to 90°C, then pre-drying at 150°C. Baking was performed for 3 minutes and water repellent treatment was performed. Furthermore, the base fabric thus obtained was subjected to a corona discharge treatment using the apparatus shown in FIG. The base fabric was fed between a pair of discharge electrodes at a speed of 10 m/min such that one layer of the base fabric was in contact with the circumferential surface of the rolled electrode connected to ground. The distance A between both electrodes is 10 mm, and the voltage is 160 on the surface of this base fabric.
Volts, current 18 amps maximum output 8kW (power consumption
Corona discharge treatment was performed continuously at a rate of 7.9kW/hr). At this time, the diameter of the metal electrode core of both electrodes is 20
cm, the thickness of the resin layer is 2 mm (roll diameter 20.4 cm),
The roll length was 2 m and the discharge width was 1.92 m. At this time, the energy radiated to the sample surface was approximately 440W/
m ² /min. For the fibrous base fabric treated with water repellent and corona discharge in this way, 100%
Part Nitsuporan 3105 and 15 parts Coronate L (both products of Nippon Polyurethane Industries Co., Ltd.: polyurethane adhesive) were diluted with ethyl acetate to make a 50% solution, and this was applied in an amount of 30 g/m ² . Dry. Next, a PVC film (0.1 mm) having the following composition was attached by heating. PVC 100 parts DOP (plasticizer) 75 parts titanium dioxide 8 parts antimony trioxide (flame retardant) 5 parts zinc stearate (stabilizer) 3 parts The resulting waterproof sheets were evaluated for their peel strength and water absorption properties. It was measured. For comparison, a comparative waterproof sheet (Comparative Example 1) was created using the above method but omitting the corona discharge treatment. Measurement method Peeling strength: JIS-K-6328-1977, 5, 3, 7
The peel test was conducted in accordance with the peel test. The condition of the peeled surface of the peeled sample was also observed. Water absorption: Take a sample 20 cm long and 3 cm wide from the double-sided coated cloth, fix the top in the length direction, and place the bottom end approximately 0.5 cm into a dipping container containing commercially available red ink diluted to 5%. Immerse it in the immersion liquid, soak it at room temperature for 24 hours, then take it out, sandwich the immersion liquid at the bottom with a piece of filter paper, wipe it gently, and measure the height at which the red ink has risen (the higher the height, the greater the water absorption). . The results are shown in Table 1. Water pressure resistance is 2000mm for both
It was above the water column.

[Table] The practical guideline for water absorption is that it should be at most 10 cm, preferably less than 5 cm, and preferably 0 cm.
It is. For this purpose, it is necessary to attach a water repellent of 1.0% owf or more. Generally, the practical guideline for peel strength is 6 kg/3 cm or more, preferably 8 to 9 kg/3 cm.
or more. As can be seen from Table 1, in the conventional method (comparative treated fabric), sample No. 3
It can be seen that only 4 to 4 have almost practical utility, while the others are unsatisfactory. Moreover, it is extremely difficult to obtain a product with stable production and stable performance under these conditions. However, according to the method of the present invention, the peeling strength is hardly affected by the concentration of water repellent as in the conventional method, and the peel strength is 1.0 owf.
High adhesive strength can be obtained even when the above water repellent is attached, and a waterproof sheet with stable product performance can be obtained under stable processing conditions. Further, in the above method, for comparison, a comparative waterproof sheet (Comparative Example 2) was prepared by subjecting the base fabric to corona discharge, followed by water repellent treatment and polymer coating. This comparative waterproof sheet also has a water repellent coating amount of 1.0.
%owf or higher, the peel strength was significantly reduced and no effect of corona discharge treatment was observed.
Furthermore, when the peeled surfaces of the peeled samples of Example 1 and Comparative Examples 1 and 2 were observed, it was found that the polymer coating was torn off on the peeled surface of the base fabric of Example 1 according to the method of the present invention. The results showed that the adhesive strength between the water repellent-treated base fabric and the polymer coating was higher than that of the polymer coating. However, in Comparative Examples 1 and 2, no polymer film was observed to remain attached on the release surface of the base fabric. That is, in Comparative Example 2, the corona discharge treatment applied to the base fabric was not effective in improving the adhesive strength between the polymer coating and the water repellent layer. Example 2 and Comparative Examples 3 and 4 Polyester spun yarn fabric: 14S/1 x 14S/1/53 pieces/inch x 50 pieces/inch plain weave, weight 190 g/m ² thickness 0.3 mm, in the same manner as in Example 1. Hobotex FTC 5
% aqueous solution, squeezed with a mangle into a pick-up of 100 g/m ² and pre-dried at 80 to 90°C. The fabric was then baked at 150° C. for 3 minutes to adhere the water repellent to obtain a treated cloth with a water repellent adhesion amount of 2.5% owf.
This treated cloth was subjected to corona discharge treatment (method of the present invention) in the same manner as in Example 1, and then subjected to waterproofing treatment under the following conditions. PVC 100 parts DOP 60 parts CaCO ₃ 20 parts Cd-Ba stabilizer 3 parts Toluene 100 parts Nituporan 3105 10 parts Coronate L Soaked in a solution of 2 parts, squeezed with a mangle and heat treated at 190℃ for 3 minutes to make PVC resin was gelled and fixed. The amount of the waterproof layer thus applied was 200 g/m ² in terms of solid content. All of the obtained waterproof fabrics had a water pressure resistance of 2000 mm or more of water column. For comparison, a comparative waterproof sheet (Comparative Example 3) was prepared using the above method but omitting corona discharge. When a truck top was made using the waterproof sheet according to the method of the present invention and put into practical use, no water seepage into the fibrous base fabric was observed, but when using the waterproof sheet of Comparative Example 3, the coating was rubbed off after about one month, and the base fabric It peeled off in a state where it partially rose from the fabric interface, the water pressure resistance decreased, and after two months it became unusable.
However, the sheet obtained by the method of the present invention did not peel off from the polymer coating even after two years of use, and no other abnormalities were observed. Further, a comparative waterproof sheet (Comparative Example 4) obtained by subjecting a base fabric for comparison to a corona discharge treatment, and then applying the water repellent treatment and coating with a polymer was treated with a water repellent agent in the polymer coating. The waterproof sheet exhibited the same unsatisfactory performance as the waterproof sheet of Comparative Example 3, including peeling from the treated base fabric interface, and no particular effect was observed in the corona discharge treatment. Example 3 and Comparative Examples 5 and 6 Glass fiber base fabric: DE150 1/2 3.3S/55 pieces/inch x 51 pieces/inch Turkish satin textured 290g/ ^m2 gray fabric was coated with a fluorine-based water-repellent and oil-repellent agent. A water repellent treated fabric was obtained by dipping it in a treatment solution containing 5% Scotchigard FC-232 (product of Sumitomo 3M), squeezing it with a pick-up to 50% using a mangle, pre-drying it, and then baking it at 150°C for 1.5 minutes. (Conventional method). Furthermore,
This was subjected to the same corona discharge treatment as in Example 1. Next, in the same manner as in Example 1, PVC films were attached to both surfaces of the water-repellent treated base fabric and the corona discharge treated base fabric by heating to obtain waterproof sheets. The water pressure resistance of the obtained sheets is
The water column was 2000 mm or more, and the water absorption was 0 in all cases. However, the peel strength of the sheet obtained by the method of the present invention was 8.6 kg/3 cm, and the PVC coating remained attached to the base fabric interface in a torn off state on the peeled surface. In contrast, the conventional method (without corona discharge treatment)
The comparative tarpaulin sheet (Comparative Example 5) is 4.0Kg/
It showed an unsatisfactory peel strength of 3 cm, and no residual PVC coating was observed on the peeled surface of the base fabric. In addition, another comparative waterproof sheet (Comparative Example 6) obtained by first corona discharge treatment on the base fabric and then water repellent treatment and polymer coating showed an insufficient peel strength of 4.0 kg/3 cm, and No residual PVC coating was observed on the peeled surface of the water repellent treated base fabric, and no effect of the corona treatment on the adhesive strength between the water repellent layer and the polymer coating was observed. As mentioned above, when using the conventional method, it is extremely difficult to obtain a waterproof sheet with a well-balanced excellent peeling strength and water repellency (water absorption prevention property), but when using the method of the present invention, it is easy to obtain Moreover, a high-performance waterproof sheet was obtained under stable processing conditions. Examples 4 to 7 and Comparative Example 7 Glass fiber base fabric: DE150 1/2 3.3S/55 pieces/inch x 51 pieces/inch Turkey satin textured 290g/ ^m2 was scoured and dried, and the following water repellent aqueous emulsion was prepared. Impregnated with liquid. Water repellent A (Example 4) 22 parts of paraffin wax with a melting point of 60°C Wax-carboxylic acid addition reaction product with an acid value of 70 and a melting point of 72°C 8 parts Aqueous ammonia 0.3 parts Water 70 parts Wax solid content 30% PH 8.3 Viscosity (25°C) <100 cp The above addition reaction product was an addition reaction product of a mixture of a low molecular weight polyolefin wax and a petroleum distillate wax with maleic anhydride. The above paraffin wax and the addition reaction product are melt-mixed at 110°C, ammonia water is added thereto, then cooled to 100°C, and boiling water is gradually added to increase the viscosity and lower the temperature. The emulsion was inverted (W/
(from O type to O/W type), a stable O/W type emulsion was obtained. Water Repellent B (Example 5) Water Repellent B was prepared by mixing Water Repellent A with the following polymer emulsion at a ratio of 3:1. (Polymer emulsion) Acrylic acid butyl ester 50 parts Acrylic acid ethyl ester 28 parts Methacrylic acid methyl ester 22 parts Unsaturated sodium sulfonate 1 part Ammonium persulfate 0.8 parts Water 136 parts Solid content 42.5% Viscosity (25℃) 40 cp PH 3.8 (Water and aqueous ammonia were added to the above polymer emulsion to adjust the pH to 7.4 and solid content to 40%.) The polymer emulsion was prepared as follows. Pour the specified amount of water into a 500c.c. four-necked kolben,
The reactor was fixed in a hot water bath, equipped with a stirrer, a reflux condenser, and a thermometer, and the entire reactor was airtight. Nitrogen gas was fed until the reaction was completed, but this gas was discharged through a cooling tube. The water bath temperature was set to around 40°C, and a separate separating funnel was attached to the remaining opening with a rubber stopper, taking care to keep it airtight. Next, 50 parts of butyl acrylate, 28 parts of ethyl acrylate, and methyl methacrylate.
22 parts of the mixture was mixed well and placed in the separatory funnel. Separately, 0.8 part of ammonium persulfate and 1 part of unsaturated sodium sulfonate were added to water in a four-necked Kolben and mixed uniformly. The external temperature was kept at 60 to 65°C, and a polymer (acrylic acid butyl ester, etc.) was added dropwise from a separating funnel, and polymerization was performed while stirring at 65 RPM. In this case, the internal temperature did not exceed 75°C due to the exothermic reaction, and the reaction was carried out while cooling the reaction by adding water to the external bath so as not to interfere with the reaction, and the polymerization reaction was completed after about 6 hours. Confirm that there is no monomer dripping from the reflux condenser while stirring for 30 minutes at an internal temperature of 80°C or higher and around 85°C. If there is no dripping, this indicates that the reaction is complete. A stable emulsion with fine particles was obtained. In both cases, the yield was close to 100%. Water repellent C (Example 6) Paraffin wax with a melting point of 60°C 30 parts Polyethylene oxide stearyl ether (HLB: 13) 8.5 parts Caustic potash 0.04 parts Water 61.5 parts Wax solid content 30% PH 7.8 Viscosity (25°C) <100 cp Repellent Water agent D (Example 7) Catalyzer RB (product of Ciba-Geigy) was added as a reaction catalyst to Hobotex FTC (product of Ciba-Geigy, amino resin derivative water repellent) at a ratio of 25% by weight to Hobotex FTC. It was mixed and used. The base fabric was immersed in each water repellent treatment solution at the above concentration, squeezed with a mangle and dried at 120°C to make the base fabric water repellent. The adhesion amount (solid content) of each water repellent agent was adjusted to be 3% based on the weight of the base fabric. In Examples 4 to 7 and Comparative Example 7, water repellents listed in Tables 2 and 3 were used. Each of the fibrous base fabrics thus obtained was further subjected to the same corona discharge treatment as in Example 1. Next, 100 parts of Nitsuporan 3105 and 15 were applied to both sides of these base fabrics.
Coronate L (both manufactured by Nippon Polyurethane Industries Co., Ltd.: polyurethane adhesive) was diluted with ethyl acetate to make a 50% solution, which was applied in an amount of 30 g/m ² and dried. Next, a PVC film (0.1 mm) having the following composition was attached by heating. PVC 100 parts DOP (plasticizer) 75 parts titanium dioxide 8 parts antimony trioxide (flame retardant) 5 parts zinc stearate (stabilizer) 3 parts Regarding these waterproof fiber sheet materials obtained, the peeling strength of the coating and Water absorption was measured. The results are shown in Table 2. Water pressure resistance is 2000mm for both
It was above the water column.

[Table] Furthermore, the folding strength of each product was measured in accordance with JIS-P-8115 (1976), "Test method for folding strength using MIT type tester for paper and paperboard".
The results shown in the table were obtained.

[Table] As can be seen from Table 3, when glass fiber base fabric is treated according to the present invention, it not only improves peel strength and water absorption, but also improves the low folding strength, which is a drawback of glass fiber base fabric. , it has a remarkable effect that was previously unimaginable in improving this, and is extremely suitable for applications that involve repeated bending (portable tents, etc.), flaps, and vibrations (open tents that are exposed to wind pressure, etc.), and other applications. Useful. The present invention is also effective in expanding the applications of flame-retardant, quasi-non-flammable, non-flammable membranes, etc. using inorganic fiber base fabrics. Examples 8-9 and Comparative Examples 8-9 Glass fiber base fabric: DE150 1/2 3.3S/55 pieces/inch x 51 pieces/inch Turkish satin texture 290g/ ^m2 was scoured and dried to make it fluorine-based water repellent. The oil agent Asahi Guard AG-740 (manufactured by Asahi Glass Co., Ltd.) is soaked in a treatment solution containing 7%, squeezed to 40% with a mangle, pre-dried, and then baked at 180℃ for 1.5 minutes to form a water repellent agent. Treated fabrics were obtained (Example 8 and Comparative Example 8). Similarly, the base fabric was scoured and dried, dipped in a treatment solution containing 5% of silicone water repellent SH-8627 (product of Toray Silicone Co., Ltd.), squeezed to 40% with a mangle, and then pre-treated. After drying, the fabrics were baked at 350°C for 5 minutes to obtain water repellent treated fabrics (Example 9 and Comparative Example 9). Half of these treated fabrics were subjected to the same corona discharge treatment as in Example 1 (Examples 8 and 9), and the remaining half were not treated (Comparative Examples 8 and 9). Then, these corona discharge treated cloths
It was immersed in a treatment solution containing 2% KBM303 (product of Shin-Etsu Silicone Co., Ltd., an epoxy silane coupling agent), squeezed with a mangle, and dried at 120°C for 3 minutes to obtain a coupling agent-treated fabric (Example 8,
9). Next, the glass fiber treated cloths obtained in this way (Examples 8 and 9, Comparative Examples 8 and 9) were coated with viscosity
100 parts of dimethylpolysiloxane endblocked with vinyl groups at both ends of 10000CS, 1.0 part of methylhydrodiene polysiloxane with a viscosity of 40CS, and a platinum compound catalyst, containing 0.11 parts of benzotriazole as an addition reaction retarder, 1.0 part of carbon black, and hydroxide. By coating a light gray paste-like addition reaction-curable silicone rubber composition containing 50 parts of aluminum powder as a flame retardant improver using a knife coater method, and heating and vulcanizing at 170°C for 5 minutes,
Flame-retardant silicone rubber layers with a thickness of 0.1 mm were formed on both sides. The peeling strength and water absorption of the resulting silicone sheet materials were measured. The results are shown in Table 4. Water pressure resistance is 2000mm for both
It was above the water column.

[Table] Silicone adhesive was used as the adhesive.
Furthermore, the folding strength of each product was measured in accordance with JIS-P-8115 (1976), "Test method for folding strength using MIT type tester for paper and paperboard", and it was found to be No. 5.
The results shown in the table were obtained.

〔Effect of the invention〕

The method of the present invention involves preparing a base fabric that has both extremely high water repellency and adhesive properties, and using this base fabric to stably manufacture a waterproof sheet having excellent waterproof performance and waterproof durability. I can do it. Therefore, the method of the present invention is extremely valuable as an industrial method for producing waterproof sheets.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram of the corona discharge treatment used in the method of the present invention. 1, 2...discharge electrode, 3,4...electrode core, 5,6...
Resin layer, 7... High voltage power supply, 8... Earth, 9, 13...
Guide roll, 10... Base fabric, 11... Surface in contact with the grounded electrode, 12... Surface in contact with the guide roll, 14... Winding roll.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a waterproof sheet by forming a polymer coating on both sides of a fibrous base fabric, in which the fibrous base fabric is first treated with a water repellent, and then both surfaces are treated with a corona coating. A method for producing a waterproof sheet, which comprises forming a polymer film on both surfaces of the sheet after discharge treatment. 2. The method according to claim 1, wherein the fibrous base fabric is made of at least one selected from natural fibers, inorganic fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers. 3. The method according to claim 1, wherein the water repellent is selected from wax, aluminum soap, zirconium salts, quaternary aluminum salts, N-methylol fatty acid amides, amino resin derivatives, fluorine compounds, and silicones. 4. The method according to claim 1, wherein the water repellent treatment is performed by an impregnation method, a coating method, or a spraying method. 5. The method according to claim 1, wherein the polymer is selected from synthetic resins, synthetic rubbers and natural rubbers. 6 Synthetic resins include polyvinyl chloride, polyurethane,
6. The method according to claim 5, wherein the resin is selected from ethylene-vinyl acetate copolymer, isotactic polypropylene, polyethylene, polyacrylonitrile, polyester, polyamide, fluororesin, and silicone resin. 7. The method according to claim 5, wherein the synthetic rubber is selected from styrene-butadiene rubber, chlorosulfonated polyethylene rubber, polyurethane rubber, butyl rubber, isopropylene rubber, silicone rubber, and fluorine rubber. 8. The method according to claim 1, wherein the polymer film is formed by a calendering method, an extrusion method, a coating method, or a dipping method. 9. The method according to claim 1, wherein the corona discharge treatment is performed at an output of 4 to 800 kW. 10. The method according to claim 1, wherein the corona discharge treatment is performed with an electrode spacing of 30 mm or less.