JPH0478670B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention provides an antifogging agent composition that can impart antifogging properties to the surfaces of various products made of glass and synthetic resin materials, and can maintain this antifogging property for a long period of time. Concerning the preparation method. (Prior Art and its Problems) In recent years, various thermoplastic resins have been industrially manufactured and used in a wide range of fields. Many of the molded products made from these thermoplastic resins have hydrophobic surfaces, so depending on the conditions such as temperature and humidity in which the molded product is used, the surface of the molded product may become cloudy and cause various problems. It's causing inconvenience. For example, goggles, safety glasses, etc. that use synthetic resin lenses may become cloudy, making it difficult to see, and food packaging films may become cloudy, making it difficult to see the contents. In addition, with agricultural films used in greenhouses, cloudy weather impairs the penetration of sunlight, slowing down plant growth, and causing cloudy microscopic water droplets to collect and fall onto cultivated plants. , young buds may be damaged or cause disease outbreaks. In order to eliminate such inconveniences, it is known that antifogging properties may be imparted to the surface of thermoplastic resin molded articles. In order to impart antifogging properties to the surface of a thermoplastic resin molded product, there is a method of kneading a hydrophilic substance such as a surfactant into the thermoplastic resin to form a molded product, or a method of kneading a hydrophilic substance such as a surfactant into the thermoplastic resin to form a molded product, or adding a method to the surface of the molded product after forming the molded product. For example, various methods have been proposed for applying a mixture of silica or alumina and a surfactant. However, in the former method, the hydrophilic substance kneaded into the thermoplastic resin bulges out and coordinates on the surface of the molded product, giving the molded product antifogging properties, but it is easily washed out by water and is short-lived. The anti-fog properties will disappear over time.
On the other hand, even in the latter method, the adhesion to the thermoplastic resin is poor, so the formed coating will fall off over time, and no matter which method is used, the anti-fogging effect cannot be maintained over a long period of time. I couldn't do it. In order to eliminate the above-mentioned drawbacks of the conventional art, the present inventor has previously developed an invention relating to an antifogging agent composition comprising a hydrophobic acrylic resin having a glass transition temperature in the range of 35 to 80°C and an inorganic colloidal sol. Special request for 1986
-223712, but this time, when mixing the aqueous dispersion of hydrophobic acrylic resin and inorganic colloidal sol, by adding a separate surfactant, the former two can be mixed extremely easily and uniformly. Furthermore, the present inventors have discovered that they have excellent adhesion to the surface of thermoplastic resin molded products and can maintain the antifogging properties of molded products over a long period of time, and have completed the present invention. That is, an object of the present invention is to provide an easy method for preparing an antifogging agent composition comprising an aqueous dispersion of a hydrophobic acrylic resin and an inorganic colloidal sol. (Means for Solving the Problems) Therefore, the gist of the present invention is to provide an aqueous dispersion and an inorganic colloidal sol of a hydrophobic acrylic resin having a glass transition temperature in the range of 35 to 80°C.
A method for preparing an antifogging agent composition, which comprises post-adding 0.1 to 50 parts by weight of a surfactant per 100 parts by weight of a hydrophobic acrylic resin. The present invention will be explained in detail below. In the present invention, the hydrophobic acrylic resin refers to alkyl esters of acrylic acid or methacrylic acid (hereinafter referred to as (meth)acrylic acid alkyl esters) containing at least 60% by weight in total. ], or a mixture consisting of monomers of (meth)acrylic acid alkyl esters and alkenylbenzenes, and 0 to 40% by weight of a copolymerizable α,β-ethylenically unsaturated monomer, by conventional polymerization. It is a water-dispersible polymer or copolymer obtained by emulsion polymerization in an aqueous medium depending on the conditions, for example, in the presence of an emulsifier. Monomers used in the production of hydrophobic acrylic resins,
As (meth)acrylic acid alkyl esters,
For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, Examples include methacrylic acid ethyl ester, methacrylic acid n-propyl ester, methacrylic acid isopropyl ester, methacrylic acid n-butyl ester, methacrylic acid 2-ethylhexyl ester, methacrylic acid decyl ester, etc. Generally, the carbon of the alkyl group Acrylic acid alkyl esters having 1 to 20 carbon atoms and/or methacrylic acid alkyl esters having alkyl groups having 1 to 20 carbon atoms are used. Examples of alkenylbenzenes include styrene, α-methylstyrene, and vinyltoluene. Such alkenylbenzenes and (meth)
When using a monomer consisting of a mixture with an acrylic acid alkyl ester, the amount of the (meth)acrylic acid alkyl ester is usually It is preferable to use a proportion of 10% by weight or more. The hydrophobic acrylic resin preferably contains alkenylbenzenes in an amount of 70% by weight or less. The hydrophobic acrylic resin used in the present invention contains at least 60% by weight of monomers consisting of the above-mentioned (meth)acrylic acid alkyl esters or a mixture of (meth)acrylic acid alkyl esters and alkenylbenzenes. %, and if it is less than 60% by weight, the formed coating film will not have sufficient water resistance and will not be able to exhibit lasting antifogging performance. Other copolymerizable α,β-ethylenically unsaturated monomers used to obtain the hydrophobic acrylic resin include, for example, acrylic acid, methacrylic acid,
α, β-ethylenically unsaturated carboxylic acids such as maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid; α, β-ethylenically unsaturated carboxylic acids such as ethylene sulfonic acid,
β-ethylenically unsaturated sulfonic acids; 2-acrylamido-2-methylpropanoic acid; α, β-ethylenically unsaturated phosphonic acids; hydroxyl group-containing vinyl monomers such as hydroxyethyl acrylic acid or methacrylic acid; acrylonitriles; Acrylamides: Examples include glycidyl esters of acrylic acid or methacrylic acid. These monomers may be used alone or in combination of two or more types, and can be used in a range of 0 to 40% by weight. If it exceeds 40% by weight,
This is not preferable because it reduces the anti-fog performance. The water-dispersible hydrophobic acrylic resin is one selected from various conventionally known emulsifiers, such as anionic surfactants, cationic surfactants, nonionic surfactants, or A method of emulsion polymerization in an aqueous medium in the presence of two or more types,
It can be obtained by a method of polymerization using a reactive emulsifier, a method of polymerization based on oligosoap theory without containing an emulsifier, and the like. In the case of a polymerization method in the presence of an emulsifier, the emulsifier is used in an amount of 0.1 to 10% by weight based on the total amount of monomers charged. If it is outside this range, it will be difficult to adjust the polymerization rate and the dispersion stability of the synthesized resin will be poor, which is not preferred. Examples of the polymerization initiator used in the production of the hydrophobic acrylic resin of the present invention include persulfates such as ammonium persulfate and potassium persulfate; organic peroxides such as acetyl peroxide and benzoyl peroxide. It will be done. These are used in an amount of 0.1 to 10% by weight based on the total amount of monomers charged. The hydrophobic acrylic resin used in the present invention must have a glass transition temperature (Tg) within the range of 35 to 80°C. Such Tg ones are
It can be obtained by selecting the type and amount (compounding amount) of the monomers used. However, if the Tg of the acrylic resin used exceeds 80°C, it is difficult to obtain a transparent and uniform coating film. In addition, when Tg is less than 35°C, the inorganic colloid particles tend to aggregate several times and become non-uniformly dispersed, and the inorganic colloid particles and surfactant are not sufficiently fixed to the coated substrate, so it takes a long time. As time passes, inorganic colloidal particles and surfactants fall off or wash away from the surface of the base material, impairing its antifogging performance. The inorganic colloidal sol, which is the active ingredient of the present invention, can be applied to the surface of a hydrophobic molded product.
It functions to impart hydrophilicity to the surface of the molded product. Examples of inorganic colloidal sols include silica,
Examples include aqueous sols in which inorganic aqueous colloidal particles such as alumina, water-insoluble lithium silicate, iron hydroxide, tin hydroxide, titanium oxide, barium sulfate, etc. are dispersed in water or a hydrophilic medium by various methods. Among them, silica sol and alumina sol are preferred. These may be used alone or in combination. The inorganic colloidal sol used preferably has an average solid particle diameter of 5 to 100 mμ. Within this range, two or more types of colloidal sols having different average particle diameters may be used in combination. When the average particle diameter exceeds 100 mμ,
This is not preferable because the coating film tends to become white and devitrified. Moreover, when it is less than 5 mμ, there is a possibility that the inorganic colloidal sol lacks stability. The amount of inorganic colloidal sol is 50 to 50% of the solid content of the acrylic resin.
Preferably it is 400% by weight. In other words, if it is less than 50% by weight, there is a risk that sufficient antifogging effect cannot be achieved, whereas if it exceeds 400% by weight,
The anti-fogging effect does not improve in proportion to the amount added, and if the molded product is transparent, the coating film formed after application becomes cloudy, which is an undesirable phenomenon that reduces light transmittance. . Moreover, the coating film tends to be rough and fragile. The surfactants added (post-added) during the preparation of the antifogging agent composition of the present invention include anionic surfactants,
Cationic surfactants, nonionic surfactants,
Examples include polymeric surfactants. Examples of anionic surfactants include fatty acid salts such as sodium oleate and potassium oleate; higher alcohol sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzenes such as sodium dodecylbenzene sulfonate and sodium alkylnaphthalene sulfonate. Sulfonates and alkylnaphthalene sulfonates; naphthalene sulfonic acid formalin condensates; dialkyl sulfosuccinates; dialkyl phosphate salts; polyoxyethylene sulfates such as sodium polyoxyethylene alkyl ether sulfate and sodium polyoxyethylene alkyl phenyl ether sulfate. There are ate salts, etc. Examples of cationic surfactants include ethanolamines; amine salts such as laurylamine acetate, triethanolamine monostearate formate; stearamide ethyl diethylamine acetate; lauryl trimethylammonium chloride, stearyl trimethylammonium chloride, dilauryl; Examples include quaternary ammonium salts such as dimethylammonium chloride, distearyldimethylammonium chloride, lauryldimethylbenzylammonium chloride, and stearyldimethylbenzylammonium chloride. Examples of nonionic surfactants include polyoxyethylene higher alcohol ethers such as polyoxyethylene lauryl alcohol, polyoxyethylene lauryl ether, and polyoxyethylene oleyl ether; polyoxyethylene octylphenol, polyoxyethylene nonylphenol, etc. Polyoxyethylene alkylaryl ethers; polyoxyethylene acyl esters such as polyethylene glycol monostearate; polypropylene glycol ethylene oxide adducts; sorbitan fatty acid esters such as sorbitan monostearate, sorbitan monopalmitate, sorbitan monobenzoate; Diglycerin fatty acid esters such as glycerin monopalmitate and diglycerin monostearate; glycerin fatty acid esters such as glycerin monostearate; pentaerythritol fatty acid esters such as pentaerythritol monostearate; dipentaerythritol monopalmitate, etc. Dipentaerythritol fatty acid esters; sorbitan and diglycerin fatty acid/dibasic acid esters such as sorbitan monopalmitate/half adipate, diglycerin monostearate/half glutamic acid ester; or these and alkylene oxides such as ethylene oxide, propylene oxide Condensates such as oxides, such as polyoxyethylene sorbitan monolaurate, polyoxypropylene sorbitan monostearate, etc.; polyoxyethylene alkyl amines such as polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearamide, etc. Fatty acid amides; sugar esters, etc. Examples of polymeric surfactants include polyacrylates, polymethacrylates, cellulose ethers, and the like. Among these surfactants, nonionic surfactants are particularly preferred. There is no problem in using these in combination. The addition of these surfactants makes it possible to uniformly disperse the hydrophobic acrylic resin and the inorganic colloidal sol very easily, quickly, and by applying them together with the inorganic colloidal sol, it is possible to form hydrophobic thermoplastic resins. It functions to synergistically impart hydrophilicity to the surface of the product. Therefore, the amount of surfactant added is required to be 0.1 to 50 parts by weight per 100 parts by weight of the solid content of the hydrophobic acrylic resin, and it is particularly preferable to select from the range of 0.5 to 3 parts by weight. When the amount of surfactant added is less than 0.1 part by weight, the uniform dispersion of the hydrophobic acrylic resin and the inorganic colloidal sol is slower than expected, and the antifogging effect cannot be sufficiently exerted when used in combination with the inorganic colloidal sol. . On the other hand, if the amount is in excess of 50 parts by weight, a bleed-out phenomenon occurs on the surface of the coating film formed after coating, which tends to reduce the transparency of the coating film and deteriorate blocking resistance. Furthermore, there is a tendency to reduce the water resistance of the dried coating. It is preferable to incorporate a crosslinking agent into the antifogging agent composition prepared according to the present invention. The acrylic resins are crosslinked with each other by the crosslinking agent, and water resistance can be improved. Examples of the crosslinking agent include phenolic resins, amino resins, amine compounds, aziridine compounds, azo compounds, isocyanate compounds, epoxy compounds, silane compounds, and especially amine compounds and aziridine compounds. , epoxy compounds are preferred. Examples of amine compounds include aliphatic polyamines such as diethylenetriamine, triethylenepentamine, and hexamethylene diamine; alicyclic amines such as 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and isophoronediamine; 4,4 Aromatic amines such as '-diaminodiphenylmethane and m-phenylenediamine are used. As aziridine compounds, tris-2,
4,6-(1-aziridinyl)-1,3,5-triazine, trimethylolpropane-tri-β-aziridinylpropionate, tris[1-(2-
methyl)aziridinyl]phosphine oxide, hexa[1-(2-methyl)-aziridinyl]triphosphatriazine, etc. are used. As epoxy compounds, bisphenol A
or reaction product of bisphenol F and epichlorohydrin, phenol (or substituted phenol)
Epoxidized novolac resins produced by the reaction of epichlorohydrin with the resin reaction product of formaldehyde and formaldehyde, epichlorohydrin and aliphatic polyhydric alcohols such as glycerol, 1,4-butanediol, poly(oxypropylene) glycol or similar polyhydric alcohols. Resin-like reaction products produced from the components and resins obtained by epoxidation with peracetic acid are used. For epoxy compounds, it is preferable to further use tertiary amines or quaternary ammonium salts as a catalyst. These crosslinking agents can be used in an amount of 0.1 to 30% by weight based on the solid content of the acrylic resin. In particular, a range of 0.5 to 10% by weight is preferred. A liquid dispersion medium may be added to the antifogging agent composition, if necessary. Such liquid dispersion media include water-containing hydrophilic or water-miscible solvents, such as water; monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; and polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin. Examples include alcohols; cyclic alcohols such as benzyl alcohol; cellosolve acetates; ketones, and the like. These liquid dispersion media may be used alone or in combination, but the dispersion stability of the antifogging agent composition according to the present invention, the wettability after coating on the surface of a molded article, the difficulty of removing the liquid dispersion medium, and the economy It is preferable to decide based on gender. Antifogging agent compositions generally consist of a solid content of hydrophobic acrylic resin, inorganic colloid, and surfactant.
It is prepared at a concentration of 0.5 to 50% by weight, usually 1 to 20% by weight, and is often used after being diluted. The antifogging agent composition prepared according to the present invention may further include an antifoaming agent, a plasticizer, a film-forming agent, a thickening agent,
Conventional additives such as pigments and pigment dispersants can be mixed. After the antifogging agent composition according to the present invention is applied to the surface of a molded article, the liquid dispersion medium is volatilized by forced drying or natural drying. As a method of forced drying, a hot air drying method, an infrared radiation method, etc. can be adopted. The heating temperature during forced drying is determined by the applied antifog composition, but is in the range of 50 to 250°C, preferably 70 to 200°C. Examples of molded products whose characteristics can be clearly recognized by applying the antifogging agent composition according to the present invention include plastics, inorganic glasses, transparent ceramics, metals, and mirror-finished materials. Among these, examples of particularly high practical value include plastic molded products, plastic films, inorganic glass lenses, building windows, bathroom windows, automobiles and trains,
Examples include windows of vehicles such as aircraft and ships. In order to apply the antifogging agent composition according to the present invention to the surface of a molded article, roll coating method, dip coating method,
Brush coating method, spray coating method, barcode method,
Any method known per se such as a knife coating method may be used. After applying the antifogging agent composition to the surface of the molded product and drying and volatilizing the liquid dispersion medium, the amount of solid matter deposited is:
It ranges from 0.01 to 10 g/m ² , preferably from 0.1 to 5 g/m ² . If the adhesion between the surface of the molded product and the coating film derived from the antifog composition according to the present invention is insufficient, the surface of the molded product may be subjected to plasma treatment before applying the antifog composition. Alternatively, the surface of the molded product may be modified by subjecting it to a corona discharge treatment. (Effects of the Invention) The present invention has the following remarkable effects and has extremely great industrial utility value. (1) According to the method for preparing the antifogging agent composition of the present invention, the aqueous dispersion of the hydrophobic acrylic resin and the inorganic colloidal sol can be easily and quickly uniformly dispersed by post-addition of the surfactant. Moreover, due to the synergistic action of the surfactant and the inorganic colloidal sol, the formed coating film exhibits extremely excellent antifogging properties, and this antifogging property can be maintained for a long period of time. (2) Since the antifogging agent composition prepared by the method of the present invention contains a hydrophobic acrylic resin, the coating film formed has excellent water resistance and is good on the surface of hydrophobic molded products. It has good adhesion. (3) In the antifogging agent composition according to the present invention, the glass transition temperature of the hydrophobic acrylic resin contained is 35 to 80°C.
Since it is within this range, it is not easily affected by the ambient temperature during use, and exhibits stable coating film performance especially under high temperature and high humidity conditions. (4) In the antifogging agent composition according to the present invention, when an inorganic colloidal sol having a specific average particle size is used, the formed coating film has excellent transparency. (5) Since the antifogging agent composition according to the present invention contains an inorganic colloidal sol, the formed coating film is excellent in non-adhesion, strength, surface hardness, and water resistance. (Examples) Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Note that the acrylic resin was manufactured as follows. Preparation of acrylic resin manufacturing examples 1 to 10 2 parts by weight of polyoxyethylene lauryl ether and 80 parts by weight of water were placed in a four-necked flask and heated to 60°C under a stream of nitrogen gas, and 0.5 parts by weight of ammonium persulfate was added thereto. Furthermore, 100 parts by weight of a mixture of each monomer shown in Table 1 below was added dropwise over 3 hours. The reaction temperature at this time is 60-70
After the completion of the dropwise addition, the temperature was maintained at the same temperature range for 2 hours, and then cooled and neutralized with aqueous ammonia to produce an aqueous dispersion of acrylic resin.
The glass transition temperature of each resin is as shown in Table 1, and is a value calculated using the following formula. 1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ ...+Wn/Tgn [Tg; Glass transition temperature (absolute temperature) of hydrophobic acrylic resin Tg ₁ , Tg ₂ , ...Tgn; Each component 1, 2...n The glass transition temperature (absolute temperature) of the homopolymer W ₁ , W ₂ ,...Wn; indicates the weight fraction of each component 1, 2...n, respectively] In Production Examples 6 and 7, the glass transition temperature is the same as that used in the present invention. Unlike hydrophobic acrylic resin, production example 8
The polymerized amount of 2-hydroxyethyl methacrylate was large and became hydrophilic.

【table】

[Table] Examples 1 to 15, Comparative Examples 1 to 10 (1) Preparation of antifogging agent composition Acrylic resin aqueous dispersions A to J obtained in the above production examples were added to the types and types shown in Table 2. Various antifogging agent compositions were prepared by blending various amounts of inorganic colloidal sol, surfactant, and other ingredients.

【table】

[Table] Notes to Table 2 *1 The amount of acrylic resin blended is the amount of polymer solids, the amount of inorganic colloidal sol is shown as the amount of inorganic particles, and the amount of surfactant is shown as the active ingredient.
*2 Aziridine compound manufactured by Sogo Yakuko Co., Ltd. *3 Bisphenol A type epoxy compound manufactured by Dainippon Ink Chemical Co., Ltd.
(2) Formation of coating film and evaluation of coating film The obtained antifogging agent composition was coated on the surface of the molded product by the bar coating method as shown in Table 3, and the coating amount after drying (as solid content) was applied to the surface of the molded product as shown in Table 3. ) was applied at a concentration of 0.5 g/m ² and allowed to stay in hot air at 90° C. for 1 minute to scatter the solvent. Various properties of the coating film formed on the obtained molded article were evaluated using the methods described below. Adhesion Cellophane tape was adhered to the surface of the molded article on which the coating was formed, and when the cellophane tape was peeled off, the peeling status of the coating was observed with the naked eye. The evaluation criteria are as follows. ○...The paint film did not peel off at all and remained completely. ○ _X : More than 2/3 of the paint film remains without peeling. △…2/3 or more of the paint film has peeled off. ×...The paint film has completely peeled off. Transparency The appearance of the molded product was observed with the naked eye. The evaluation criteria are as follows. ○...The transparency is almost the same as that of a molded product that is not coated with an antifogging composition. ○ _X : A slight decrease in transparency is observed. △…Significant reduction in transparency is observed. ×: Transparency decreases so drastically that it cannot be put into practical use. Blocking resistance The coated side and untreated side of the molded product were stacked together and left in a gear oven at 50°C under a load of 2 kg for 1 day, then the test piece was taken out and the state of peeling in the overlapped area was observed with the naked eye. I observed it. The evaluation criteria are as follows. ○: Can be removed with almost no resistance and no damage to the paint film has occurred. _○ △: There is resistance to peeling off, and half of the coating film is destroyed. ×: There is significant resistance to peeling off, and most of the paint film is destroyed. Anti-fogging properties Condition 1 Place the molded product on the top of a water tank with the coated surface facing towards the inside of the tank, maintain the outside temperature at 20°C and the inside temperature at 50°C. After placing the molded item on the top
After 30 minutes and after 120 minutes,
Judgment was made by visual observation. The evaluation criteria are as follows. ◎…Water adheres in a thin film and no water droplets are observed. ○…Water is attached in a thin film, but slightly large water droplets are observed. _○ △…A state in which fine water droplets are observed to be attached partially. ×: Condition in which fine water droplets are observed on the entire inner surface of the molded product. Condition 2 The molded product was coated on a single-roofed house (frontage 2 m, depth 20 m, ridge height 2 m, roof slope 30 degrees) installed in an outdoor test field, with the coated side facing inside the house. Expansion tests were conducted for 18 months from April to September of the following year. During the stretching test, the antifogging properties of each molded article were visually observed over time. This evaluation criteria is
This is the same as in Condition 1 above. These evaluation results are shown in Table 3.

【table】

[Table] *4 During the outdoor extension test, the film hardened and tore, so it was not possible to continue the test.

Claims (1)

[Claims] 1. 0.1 per 100 parts by weight of the hydrophobic acrylic resin to an aqueous dispersion and an inorganic colloidal sol of a hydrophobic acrylic resin having a glass transition temperature in the range of 35 to 80°C.
A method for preparing an antifogging agent composition, characterized in that ~50 parts by weight of a surfactant are post-added. 2. The hydrophobic acrylic resin is produced using a monomer consisting of an alkyl ester of acrylic acid or methacrylic acid, or a monomer mixture of an alkyl ester of acrylic acid or methacrylic acid and an alkenylbenzene as a main component. A method for preparing an antifogging agent composition according to claim 1, which is a polymer or a copolymer. 3 The solid average particle diameter of the inorganic colloidal sol is 5~
A method for preparing an antifogging agent composition according to claim 1, which has a particle size in the range of 100 mμ. 4. The method for preparing an antifogging agent composition according to claim 1, wherein the inorganic colloidal sol is silica sol or alumina sol. 5. The method for preparing an antifogging agent composition according to claim 1, wherein the surfactant is a nonionic surfactant. 6. A method for preparing an antifogging agent composition according to claim 1, which contains a crosslinking agent for a hydrophobic acrylic resin.