JPS6247226B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention provides an excellent and long-lasting effect that can be achieved by simply bringing the surface of a synthetic resin film, sheet, panel, glass, metal, etc. into contact with a surface treated with a synthetic resin (hereinafter referred to as a synthetic resin surface). This invention relates to a drip-proof agent that provides drip-proof properties. As is well known, transparent or semi-transparent synthetic resin films are used as covering materials in agricultural and fisheries greenhouses where crops, fish, and the like are cultivated and cultured.
This coating material is made of hard or soft vinyl chloride resin,
It is a film or sheet made of polyethylene, ethylene-vinyl acetate copolymer, or a sheet or panel made of acrylic resin or polyester resin reinforced with glass fiber, and most of its surfaces are hydrophobic. In such a greenhouse, if the temperature inside the greenhouse is set higher than the outside temperature so that the temperature is suitable for cultivation, dew condensation will occur on the inner surfaces of the synthetic resin plates. Water droplets produced by dew condensation, regardless of their size, block the passage of sunlight, and as they grow, they drip, causing various obstacles to the growth of crops and fish. Furthermore, lenses of glasses, cameras, and the like made of synthetic resin or glass whose surface has been treated with synthetic resin often fog up due to the adhesion of fine water droplets in humid environments. As anti-fogging and drip-proofing measures, various surfactants and other chemicals have conventionally been mixed into the synthetic resin or coated on the surface of the synthetic resin. However, these methods have the following drawbacks. (1) If anionic, nonionic, or cationic surfactants are used as drip-proofing agents, since they are water-soluble, they tend to flow out from the synthetic resin surface due to condensation, resulting in poor sustainability of the effect. (2) If plasticizers, stabilizers, etc. in the synthetic resin migrate or volatilize and are discharged or recondensed onto the surface, or if oils, dust, or other contaminants scattered during various operations adhere to the synthetic resin surface, the synthetic resin Since the surface is always hydrophobic, even if a drip-proofing agent is mixed into the synthetic resin in advance, it is difficult to maintain drip-proof properties for a period that is sufficient for the mechanical and physical usable life of the synthetic resin body. It is. Therefore, there is a need to extend the drip-proof retention time while preventing contamination of the synthetic resin surface, and to be able to immediately reprocess it if the drip-proof effect deteriorates. Thus, the inventors of the present invention have completed the present invention as a result of repeated studies in order to meet the above-mentioned demands. The first feature of the present invention is that the synthetic resin surface has a strong drip-proofing effect, and the duration of the drip-proofing property is significantly extended. Another feature of the present invention is that the coating amount is small and sufficient drip-proofing effect is achieved just by forming a thin film layer on the synthetic resin surface, so that the transparency of the synthetic resin surface is not impaired. Another feature of the invention is that the processing operation is extremely simple. For example, you can simply dilute the undiluted solution with water on-site, or spray, sprinkle, or apply the solution diluted with water in advance onto the synthetic resin surface, and the drip-proof effect can be achieved immediately without post-treatment such as heating or drying. able to demonstrate. Another feature of the present invention is that it has good wettability and strong adhesion to synthetic resin surfaces made of various materials, so that a wide range of objects can be treated with drip-proof treatment. That is, the above-mentioned agricultural and fishery greenhouse;
It can be directly attached to various materials such as glasses, goggles, building windows, automobile glass, etc. by spraying, scattering, coating, etc., even if the treated surface is dry or wet. In most cases, it is not necessary to remove these deposits in advance even if they are contaminated with oil components or dust, or have drip-proofing agents that have lost their effectiveness. The present invention relates to a drip-proofing agent whose main component is a composition prepared by heating a mixture of silica and an organic silane compound. More specifically _, using an organic silane compound specified as A solution (hereinafter referred to as The synthetic resin surface is treated using a quasi-colloidal solution (referred to as a quasi-colloidal solution), and if necessary, an aqueous polymeric substance, a surfactant, and a water-soluble organic solvent may be mixed therein. Silica in the present invention is fine particles of basic unit SiO ₂ with an average particle diameter of 0.1 to 50 mμ that is dispersed in water to form a quasi-colloidal solution, but in actual use, silica fine powder, which is commercially available as silica, is Dispersed in water or produced by other known methods, solid content concentration 10-40% by weight
It is preferable to use so-called silica sol as a raw material. Examples of organic silane compounds having a general formula specific to the present invention include those illustrated below. (1) H ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) ₃ (2) H ₂ N (CH ₂ ) ₃ Si (OC ₂ H ₅ ) _3All of the above-mentioned organosilane compounds are easily hydrolyzed, When hydrolyzed, it is covalently bonded or physically adsorbed to the surface of colloidal silica particles, forming an organic silica layer as the outermost layer. On the other hand, when water-soluble polymer substances, surfactants, and water-soluble organic solvents are sprayed, scattered, or applied onto synthetic resin surfaces, they further improve wetting of the synthetic resin surface and spread the main component evenly over the entire surface. Preferred examples of water-soluble polymer substances include non-dissociable or dissociable polymers that generate polymer anions, such as polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and sodium carboxymethyl cellulose. It is a substance. Preferred examples of surfactants include polyoxyethylene monoalkyl ether, polyoxyethylene monoalkyl ether, N-alkylpolyoxyethylene perfluoroalkyl sulfonate, fatty acid monoglyceride sulfate salt, long-chain alkyl sulfate salt, and long-chain alkyl sulfate salt. Nonionic or anionic surfactants represented by chain alkyl allyl sulfate salts, perfluoroalkyl sulfate salts, long chain alkyl sulfonate salts, etc. Preferred examples of water-soluble organic solvents include glycidol and ethyl alcohol. , ethylene glycol, polyethylene glycol, etc. The drip-proofing agent of the present invention can be produced extremely easily. For example, a silica colloid aqueous solution is supplied to a tank equipped with a stirrer, and an organic silane compound is further added to the temperature range not exceeding 70°C, preferably 50 to 70°C.
Stir for at least 60 minutes while heating. When a mixture of a silica colloid and an organic silane compound is sufficiently stirred while being heated in the above temperature range, a uniform colloid solution composition is obtained as a whole. Note that if the heating temperature exceeds 70°C, the particles will aggregate and become coarse, resulting in a drop in drip-proof function. Furthermore, below 50°C, the reaction rate decreases and the production efficiency decreases. A water-soluble polymer substance is added to this colloidal solution as needed so that the weight ratio to silica is about 0.5 to 20%, and the mixture is stirred.If more spreadability is desired, the weight ratio to silica is 0.05 to 2.
% of a surfactant and further a water-soluble organic solvent are added and stirred. However, adding large amounts of surfactants or water-soluble organic solvents may impair the sustainability of the drip-proof effect when they adhere to synthetic resin surfaces. Preferably, only the molecular substance is added in an amount of 1 to 10% by weight relative to the silica. The drip-proofing agent of the present invention is a condensation adduct (organosilane compound) obtained by reacting silica and an organic silane compound at a mole percentage of 0.001 to 3%, preferably 0.05 to 1%, of the organic silane compound relative to Si in the silica. The main component is silica bonded to the surface, but the molar ratio of organic silane compound to silica is 0.01/
When it is less than 100, the adhesion of the silica particles to the synthetic resin surface hardly changes, and the sustainability improvement effect of the organic silane compound is no longer apparent. Even if the amount exceeds 3/100, no further improvement in sustainability is observed due to the organic silane compound, and moreover, the organic silane compounds form coarse insoluble matter by condensation with each other, and crystallize after adhering to the synthetic resin surface. Inconveniences such as precipitation may occur. Therefore, in the present invention, the blending ratio of silica and organic silane compound is specified as described above. To use the drip-proofing agent of the present invention, dilute it with water to a silica solid content concentration of 0.05 to 2% by weight, generally 0.1 to 1% by weight, and reduce the silica solid content per 1 m ² of synthetic resin surface. so that it contains 0.05~0.5g
Spray, sprinkle, apply, or dip in a solution of 50ml or more. When spraying, the diluted solution can be placed in an air spray can, and conventionally known means can be used for spraying or coating. If the synthetic resin surface is contaminated or has moisture attached, it is preferable to increase the concentration higher than that for a dry or clean surface. In this way, after the drip-proof agent is attached to the synthetic resin surface, the drip-proof function can be immediately maintained for a long period of time without heating or drying. (Test method for drip-proof performance) The drawing shows a test device for determining the performance of the drip-proof agent of the present invention. In this figure, A is a steam generating tank (30 x 30 x 30 cm) with an open top, which maintains a water volume of 20 cm deep and heats it to 90±2°C. A net is placed on the top surface of the steam generating tank A, and a glass box B (32 x 32 x 30 cm) with an open bottom that allows the inside to be seen is placed on top of the screen. There is a test piece mounting box C in the center of the glass box B.
(20 x 20 x 20 cm) and attach the film, panel, or sheet to be tested to the window D (6 x 14 cm) provided on the side wall of the mounting box C. Fill with water and drain. The steam chamber E, which is a space sandwiched between the glass box B and the mounting box C, has a temperature of 55 to 60°C and a relative humidity of almost 100%. Water vapor condenses continuously on the specimen facing this environment, but the water droplet adhesion area is 20% of the total area.
Measure the time it takes to reach this point and use it as the drip-proof duration. All of the drip-proof durations shown in the Examples below were measured by the method described above. Example 1 Silica colloid aqueous solution [Snowtex C manufactured by Nissan Chemical Industries, Ltd., _SiO2 content 20% by weight, PH8.5~
9.0) Collect 85 parts by weight in a heatable container, and gradually add 0.5 parts by weight of γ-aminopropyltriethoxysilane (KBE903, manufactured by Shin-Etsu Chemical Co., Ltd.) while continuing to stir. After addition, gradually heat to 50-70℃
After stirring for 60 minutes while maintaining the liquid temperature, 14.5 parts by weight of water was added to obtain 100 parts of a homogeneous modified silica solution with a silica solid content concentration of 17.5% by weight. The resulting reaction product liquid was diluted with water to 90 parts by weight to obtain a drip-proofing agent with a silica solid content concentration of 0.2% by weight. Example 2 70 parts by weight of water was collected into the apparatus used in Example 1, and
Add 0.2 parts by weight of monoethanolamine to prepare an aqueous solution with a pH of 8.5, and add silica particles (Japan Aerological Products, Aerological
200) 85 parts by weight was gradually added to prepare a homogeneous silica colloid solution. This silica colloidal solution was prepared in the same manner as in Example 1 to obtain γ-aminopropyltriethoxysilane [Shin-Etsu Chemical Co., Ltd. product KBE903].
0.3 parts by weight was added and dissolved with heating to obtain a reaction product. To this, 1 part by weight of polyvinyl alcohol [Gohsenol GH17 manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.] and 0.1 part by weight of a nonionic surfactant [Neugen EA130T manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] were added to 18.4 parts by weight of water in advance. The dissolved aqueous solution was added and heated and stirred for 15 minutes to obtain 100 parts by weight of a milky white translucent colloidal solution with a silica solid content concentration of 11.6% by weight. This was diluted to 60 parts by weight with water to obtain a drip-proofing agent with a silica solid content concentration of 0.2% by weight. Comparative Example 1 Snowtex O 80% by weight Water 20% by weight The above liquid composition having a solid content concentration of 19% by weight was diluted to 95 parts by weight to obtain a test liquid having a solid content concentration of 0.2% by weight. Description of product name Snowtics O; manufactured by Nissan Chemical Co., Ltd. SiO ₂ 20% by weight Comparative example of silica colloid solution at pH 3.5 2 Snowtics C 80% by weight Paru 3608 1.5% by weight Gohsenol GH-17 1% by weight Water 17.5% by weight Above solids A composition liquid with a solid content of 18.5% by weight was diluted 90 times to obtain a test liquid with a solid content of 0.2% by weight. Description of product name Snowtex C: SiO ₂ 20% by weight PH8.7 silica colloid solution Paru 3608; Nonylphenol 1 manufactured by Marubishi Yuka Co., Ltd.
condensate of 8 moles of ethylene oxide and 8 moles of ethylene oxide Gohsenol GH; Polyvinyl alcohol manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd. The drip-proofing agents of Examples 1 and 2 and Comparative Examples 1 and 2 were applied to a soft polyvinyl chloride film with a thickness of 0.1 mm. and 50ml/1.2mm thick polymethyl methacrylate plate.
The test pieces were sprayed at a ratio of m ² and the drip-proof duration was measured by the method described above. The results are shown in Table 1. 【table】

[Brief explanation of the drawing]

The drawing is a schematic diagram of a drip-proof performance test device.

Claims (1)

[Claims] 1 For a silica colloid aqueous solution, the general formula
An organic silane compound represented by Si-Y ₃ (where X is a γ-aminopropyl group and Y is an alkoxy group having 1 or 2 carbon atoms) is added in a molar ratio of 0.01/100 to 3/100 to Si in the silica. Synthetic resin that imparts water repellency to the surface of a synthetic resin characterized by being made of a colloidal solution obtained by dispersing the composition obtained by mixing the composition within a temperature range of 70°C and heating for 60 minutes or more in a temperature range not exceeding 70°C in water. A drip-proof agent that prevents water droplets from adhering to surfaces.