JP2874614B2 - Antifoggant composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention imparts anti-fogging properties to the surface of various products made of glass and synthetic resin materials, and can particularly maintain the anti-fogging speed and anti-fogging properties over a long period of time. The present invention relates to an antifogging composition.

[0002]

2. Description of the Related Art In recent years, various thermoplastic resins have been industrially manufactured and used in a wide range of fields. Many molded articles manufactured from these thermoplastic resins have a hydrophobic surface, and depending on the temperature, humidity, and other conditions at which the molded article is used, the surface of the molded article may become cloudy, causing various inconveniences. I'm coming. For example, in goggles, safety glasses, and the like using a synthetic resin lens, the view becomes invisible due to fogging, and in a food packaging film, the contents become difficult to see due to fogging. In addition, in agricultural films used in greenhouses, the penetration of sunlight is deteriorated due to cloudiness, the growth of plants is slowed down, and water droplets generated by aggregation of cloudy fine water droplets fall on cultivated plants by The germ may be harmed or cause disease.

It is known that in order to solve such inconvenience, it is only necessary to impart anti-fogging property to the surface of a thermoplastic resin molded product. To impart anti-fog properties to the surface of a thermoplastic resin molded article, a method of kneading a hydrophilic substance such as a surfactant into a thermoplastic resin to form a molded article, or after forming a molded article, apply For example, various methods have been proposed for applying a mixture of silica or alumina and a surfactant. However, in the former method, the time required for the hydrophilic substance kneaded in the thermoplastic resin to be wiped out and coordinated on the surface of the molded article, impart antifogging property to the molded article, and develop the antifogging property is short. However, it is easily washed away by water and loses its antifogging properties in a short time. On the other hand, even in the latter method, since the adhesion with the thermoplastic resin is poor, the formed coating film falls off with the passage of time, and the speed of developing the anti-fog property and the continuation of the anti-fog effect can be achieved by either method. Sex was not compatible.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned drawbacks, the present inventor has set a glass transition temperature of 35.
An invention relating to an antifogging agent composition comprising a hydrophobic acrylic resin and an inorganic colloid sol having a temperature in the range of -80 ° C has been proposed as Japanese Patent Application Laid-Open No. 62-246984, but this time, an aqueous dispersion of the hydrophobic acrylic resin has been proposed. By adding a monovalent electrolyte separately when mixing the inorganic colloidal sol with the resin, the adhesion to the surface of the thermoplastic resin molded product is excellent, the time to develop anti-fog properties is short, and molding is performed for a long time It has been found that the antifogging property of the product can be maintained, and the present invention has been completed.

[0005]

The gist of the present invention is to provide (a) an aqueous dispersion of a hydrophobic acrylic resin having a glass transition temperature in the range of 35 to 80 ° C., and (b) an inorganic colloid sol. , (C) a monovalent electrolyte (excluding chlorine compounds) as an essential component, and 0.01 to 30 parts by weight of the component (c) based on 100 parts by weight of the solid content of the component (b). In the antifogging agent composition.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The hydrophobic acrylic resin, which is the component (a) of the antifogging agent composition of the present invention, may have any glass transition temperature in the range of 35 to 80 ° C., but may be any of alkyl (meth) acrylates or ( It is obtained by polymerizing at least 60% by weight of a mixture of alkyl (meth) acrylates and alkenylbenzenes and 0 to 40% by weight of an α, β-ethylenically unsaturated monomer copolymerizable therewith. Homopolymers or copolymers are preferred.

[0007] Alkyl (meth) acrylates are alkyl esters of acrylic acid or methacrylic acid, and specifically include, for example, methyl acrylate, ethyl acrylate, and n-propyl acrylate. Isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, Methacrylic acid-n-butyl ester, methacrylic acid-2-ethylhexyl ester,
And methacrylic acid decyl ester.
An alkyl acrylate having 1 to 20 carbon atoms in an alkyl group and / or an alkyl methacrylate having 1 to 20 carbon atoms in an alkyl group are used.

The alkenylbenzenes include, for example, styrene, α-methylstyrene, vinyltoluene and the like. When a mixture of alkenylbenzenes and alkyl (meth) acrylates is used, α,
Although it varies depending on the amount of the β-ethylenically unsaturated monomer used, it is usually preferable to use the (meth) acrylic acid alkyl ester in an amount of 10% by weight or more, and occupy in the hydrophobic acrylic resin. Those containing alkenylbenzenes in a range of 70% by weight or less are preferred.

The hydrophobic acrylic resin used in the present invention is:
It contains at least 60% by weight of a (meth) acrylic acid alkyl ester or a mixture thereof with an alkenylbenzene, and when the amount is less than 60% by weight, the formed coating film has insufficient water resistance, Anti-fog sustaining performance cannot be exhibited. As the α, β-ethylenically unsaturated monomer copolymerizable with the alkyl (meth) acrylate or a mixture thereof with an alkenylbenzene,
For example, α, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid
β-ethylenically unsaturated carboxylic acids; α, β-ethylenically unsaturated sulfonic acids such as ethylene sulfonic acid; 2
-Acrylamide-2-methylpropanoic acid; α, β-ethylenically unsaturated phosphonic acids; hydroxyl-containing vinyl monomers such as hydroxyethyl of acrylic acid or methacrylic acid;
Acrylonitriles; acrylamides; glycidyl esters of acrylic acid or methacrylic acid. These monomers may be used alone or in combination of two or more, and may be used in the range of 0 to 40% by weight. If it exceeds 40% by weight, the antifogging performance is undesirably reduced.

As a method of polymerizing a hydrophobic acrylic resin from these monomers, various conventionally known emulsifiers such as an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used. Emulsion polymerization in aqueous medium in the presence of one or more selected from emulsifiers, polymerization using reactive emulsifier, polymerization based on oligosoap theory without emulsifier And so on. In the case of the polymerization method in the presence of an emulsifier, these emulsifiers are used in an amount of 0.1 to the total amount of charged monomers.
It is used in the range of 1 to 10% by weight. Outside this range, it is difficult to control the polymerization rate, and the dispersion stability of the synthesized resin is poor.

Examples of the polymerization initiator used for producing the hydrophobic acrylic resin include persulfates such as ammonium persulfate and potassium persulfate, and organic peroxides such as acetyl peroxide and benzoyl peroxide. Can be These are 0.1 to 0.1 based on the total amount of charged monomers.
Used in the range of 10% by weight. The hydrophobic acrylic resin of the present invention has a glass transition temperature (Tg) of 35.
Must be in the range of ８０80 ° C. Such Tg can be obtained by selecting the type of the monomer to be used and the amount to be used (blended amount). If the Tg of the acrylic resin used exceeds 80 ° C., it is difficult to obtain a transparent and uniform coating film. When the Tg is less than 35 ° C., the inorganic colloid particles are easily aggregated several times to form a non-uniform dispersion state, and the inorganic colloid particles are not sufficiently fixed to the coating substrate. Colloidal particles fall off or flow off the surface of the base material, thereby impairing the antifogging performance.

The aqueous emulsion of the hydrophobic acrylic resin, which is the component (a) of the composition of the present invention, can be used as it is by using the aqueous emulsion obtained by polymerizing each monomer in an aqueous medium as it is. This may be diluted by adding a liquid dispersion medium, or a polymer produced by the above-described polymerization may be separately collected and redispersed in a liquid dispersion medium to form an aqueous emulsion.

The inorganic colloid sol, which is the component (b) of the antifogging agent composition of the present invention, has a function of imparting hydrophilicity to the surface of a molded article by applying it to the surface of a hydrophobic molded article. As the inorganic colloid sol, for example, silica, alumina, water-insoluble lithium silicate, iron hydroxide, tin hydroxide, titanium oxide, inorganic aqueous colloid particles such as barium sulfate, by various methods, dispersed in water or a hydrophilic medium. And an aqueous sol. Among them, silica sol and alumina sol are preferable. They are,
They may be used alone or in combination. The inorganic colloid sol used has a solid average particle diameter of 5 to 100 μm.
Are preferred. Within this range, two or more types of colloid sols having different average particle sizes may be used in combination. If the average particle diameter exceeds 100 μm, not only does the coating film tend to be white and devitrified, but also the antifogging durability decreases, which is not preferred. If it is less than 5 μm, the stability of the inorganic colloid sol may be lacking.

The amount of the inorganic colloid sol is preferably 0.5 to 4 based on the acrylic resin in terms of solids weight ratio. That is, when it is less than 0.5, a sufficient antifogging effect cannot be exhibited. When it exceeds 4, not only does the anti-fog effect not increase in proportion to the blending amount, but when the molded article is transparent, the coating film formed after application becomes cloudy and reduces the light transmittance. This is not preferred because the coating is rough and vulnerable to weakness.

The monovalent electrolyte which is the component (c) of the antifogging agent composition of the present invention may be any electrolyte compound other than a chlorine compound, and specifically, nitric acid, an alkali metal or an alkali metal. Examples include strong electrolytes such as earth metal hydroxides and inorganic salts, and weak electrolytes such as organic acids and organic bases. As strong electrolytes, nitric acid, inorganic acids such as hydrogen bromide,
Inorganic hydroxides such as potassium hydroxide, lithium hydroxide and sodium hydroxide, sodium bromide, sodium iodide, potassium bromide, potassium nitrate, rubidium bromide, rubidium iodide, cesium bromide, cesium iodide, silver nitrate And inorganic salts such as ammonium bromide and ammonium iodide. Specific examples of the weak electrolyte include acetic acid, ammonium acetate, potassium acetate, and sodium acetate. These electrolytes may be used alone or in combination of two or more.

The amount of the monovalent electrolyte is 0.01 to 100 parts by weight of the solid content of the inorganic colloid sol.
The amount is 30 parts by weight, preferably 0.01 to 20 parts by weight, particularly preferably 0.01 to 10 parts by weight. If the electrolyte is a liquid, it refers to the weight of 100% active ingredient. The amount added is 0.01
When the amount is less than 10 parts by weight, it takes time to exhibit anti-fogging properties. It is not preferable because the speed of developing the haze becomes slow.

The antifogging agent composition prepared according to the present invention preferably contains a crosslinking agent. The acrylic resin is cross-linked by the cross-linking agent, and the water resistance can be improved. Examples of the cross-linking agent include phenolic resins, amino resins, amine compounds, aziridine compounds, azo compounds, isocyanate compounds, epoxy compounds, silane compounds, and the like. Particularly, amine compounds,
Aziridine compounds and epoxy compounds are preferred.

Examples of the amine compounds include aliphatic polyamines such as diethylenetriamine, triethylenepentamine and hexamethylenediamine; 3,3′-dimethyl-4,
Alicyclic amines such as 4'-diaminodicyclohexylmethane and isophoronediamine; and aromatic amines such as 4,4'-diaminodiphenylmethane and m-phenylenediamine are used.

Aziridine compounds include 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 and the like are used.

Epoxy compounds include epoxidized novolak resin formed by the reaction of epichlorohydrin with the reaction product of bisphenol A or phenol F with epichlorohydrin, resin reaction product of phenol (or substituted phenol) with formaldehyde, epichlorohydrin And aliphatic polyhydric alcohols such as glycerol, 1,4-butanediol, poly (oxypropylene) glycol or similar polyhydric alcohol components, resinous reaction products, and resins obtained by epoxidation using peracetic acid, etc. Is used. In the case of epoxy compounds, it is preferable to use a tertiary amine or a quaternary ammonium salt in combination 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, the range of 0.5 to 10% by weight is preferable.

The antifogging agent composition is usually used in a liquid state. The liquid dispersion medium includes an affinity or water-miscible solvent including water, and water; monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin; Cyclic alcohols such as benzyl alcohol; cellosolve acetates; ketones and the like. These may be used alone or in combination, but are determined in consideration of the dispersion stability of the anti-fogging agent composition to be used, the wettability after being applied to the film surface, the difficulty of removing the liquid dispersion medium and the economic efficiency. Is preferred.

The antifogging agent composition comprises a hydrophobic acrylic resin,
The solid content of the inorganic colloid is generally prepared at a concentration of 0.5 to 50% by weight, usually prepared at a concentration of 1 to 20% by weight, and this is often used after dilution. The antifogging agent composition prepared in the present invention may further contain, if necessary, conventional additives such as an antifoaming agent, a plasticizer, a film-forming aid, a thickener, a pigment, and a pigment dispersant. it can.

The antifogging agent composition according to the present invention is applied to the surface of a molded article, and is forcibly dried or air-dried, and a coating film is formed by evaporating a liquid dispersion medium to thereby prevent the surface of the molded article. It develops cloudiness. As a method of forced drying, a hot air drying method, an infrared radiation method, or the like can be employed.
The heating temperature at the time of forced drying is determined by the applied anti-fogging agent composition, and is in the range of 50 to 250 ° C, preferably 70 to 200 ° C.

Examples of molded articles whose characteristics are remarkably recognized by applying the antifogging agent composition of the present invention include plastics, inorganic glasses, transparent ceramics, metals, mirror materials and the like. Among these, examples of particularly high practical value include plastic molded products, plastic films, inorganic glass lenses, windows of buildings, windows of bathrooms, windows of vehicles such as automobiles or trains, aircraft, ships and the like. Can be In order to apply the antifogging agent composition of the present invention to the surface of a molded article, any method known per se such as a roll coating method, a dip coating method, a brush coating method, a spray coating method, a bar coating method, a knife coating method, etc. Good.

After the antifogging agent composition is applied to the surface of the molded article, and the liquid dispersion medium is dried and volatilized, the adhered amount of the solid substance is as follows:
0.01 to 10 g / m ² , preferably 0.1 to 5 g / m ²
It is in the range of ² . If the adhesion between the molded article surface and the coating film derived from the antifogging agent composition according to the present invention is not sufficient,
Before applying the antifogging agent composition, the surface of the molded article is preferably modified by subjecting the surface of the molded article to a plasma treatment or a corona discharge treatment.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments, but the present invention is not limited to the following examples unless it exceeds the gist. (1) Preparation of Acrylic Resin Resins A to D Into a four-necked flask were charged 2 parts by weight of polyoxyethylene lauryl ether and 80 parts by weight of water, and heated to 60 ° C. under a stream of nitrogen gas. 5 parts by weight were added, and 100 parts by weight of a mixture of each monomer shown in Table 1 was added dropwise over 3 hours. At this time, the reaction temperature was maintained in the range of 60 to 70 ° C., and after the completion of the dropwise addition, the temperature was maintained at the same temperature range for 2 hours, followed by cooling to produce an aqueous dispersion of an acrylic resin. The glass transition temperature of each resin is as shown in Table 1, and is a value calculated by the following equation.

[0027]

1 / Tg = (W ₁ / Tg ₁ ) + (W ₂ / T
g ₂ )... + (W _n / Tg _n ) [Tg; glass transition temperature of hydrophobic acrylic resin (K
_{°) Tg 1, Tg 2,} ··· Tg n; components 1, 2 · · · n
The glass transition temperature (K °) of the homopolymer of W ₁ , W ₂ ,... W _n ;

[0028]

[Table 1]

(2) Preparation of antifoggant composition Acrylic resin aqueous dispersion A obtained in the above Production Example
To D, the types and amounts of inorganic colloid sols, monovalent electrolytes and other components shown in Table 2 were blended to prepare various antifogging compositions.

[0030]

[Table 2]

[0031]

[Table 3]

Notes to Table 2 * 1: Indicates the amount of polymer solids in the aqueous emulsion * 2: Indicates the amount of inorganic particles * 3: Indicates acetic acid in a 90% acetic acid aqueous solution * 4: Water / ethanol is 3 * 5: Aziridine-based compound manufactured by Mutual Pharmaceutical Co., Ltd. * 6: Epicron 860, bisphenol A type epoxy compound manufactured by Dainippon Ink Co., Ltd. * 7: Abbreviation of tetraethylenepentamine

The obtained antifogging agent composition was applied to the surface of the molded article shown in Table 3 by a bar coating method so that the coating amount (as solid content) after drying was 0.5 g / m ^2. Then, the mixture was kept in hot air at 90 ° C. for 1 minute to disperse the solvent. Regarding the properties of the coating film formed on the obtained molded product,
Various properties were evaluated by the methods described below.

Adhesion A cellophane tape is adhered to the surface of the molded product on which the coating film is formed,
When the cellophane tape was peeled off, the peeling state of the coating film was visually observed. The evaluation criteria are as follows.・ ・ ・: The coating film did not peel at all and remained completely. Ｘx: 2/3 or more of the coating film remained without peeling. Δ: 2/3 or more of the coating film peeled off. ×: The coating film was completely peeled off.

Transparency The appearance of the molded article was visually observed. The evaluation criteria are as follows. ○ ・ ・ ・ Compared with a molded article to which the antifogging agent composition is not applied,
Those with almost the same transparency. ○ x: Transparency is slightly reduced. Δ: A significant decrease in transparency was observed. X: Transparency is extremely severe and is not practical.

Blocking resistance The surface of the molded product on which the coating film is formed and the untreated surface are overlapped,
After being left for 1 day under a load of 2 kg in a 50 ° C. gear oven, the test piece was taken out, and the peeling state of the overlapped portion was visually observed. The evaluation criteria are as follows.・ ・ ・: A film which can be peeled off with almost no resistance and does not break the coating film. ○ x: Some resistance to peeling, part of coating film is broken. Δ: Resistance to peeling, half of the coating film was broken. X: A film having extremely resistance to peeling and most of the coating film is broken.

Anti-fogging property i) Condition 1 The surface on which the coating film of the molded article was formed was placed on the top of a water tank filled with water, facing the inside of the water tank. At 5 minutes and 10 minutes after the holding and holding of the molded article on the upper part of the water tank, the appearance speed of the antifogging property was visually observed and determined at each time point. The evaluation criteria are as follows. ◎: A state in which water adheres in a thin film form and no water droplets are observed. : Water is attached in a thin film state, but slightly large water droplets are observed. X: a state in which water adheres in the form of a thin film, but adhesion of large water droplets is partially observed. Δ: A state in which fine water droplets are partially adhered. ×: A state in which fine water droplets adhere to the entire inner surface of the molded article.

Ii) Condition 2 The molded article was placed in a single-roof house (frontage 2 m, depth 20 m, building height 2 m, roof slope 30
On the other hand, coating was performed with the surface provided with the coating film inside the house, and a stretching test was conducted for 18 months from April to September of the following year. During the extension test, the antifogging property of each molded article was visually observed with time. This evaluation criterion is the same as that in the above condition 1. Table 3 shows the results of these evaluations.

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

The antifogging agent composition of the present invention can be used as an antifogging agent because it is rapidly applied to molded articles and exhibits antifogging properties quickly and the antifogging properties are maintained for a long period of time. The value is extremely large.

Continued on the front page (72) Inventor Kazuya Kinoshita 2 Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi Pref. Nagoya Office of Mitsubishi Chemical MKV Corporation Co., Ltd. (56) References JP-A-51-81877 (JP, A) JP 4-78670 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09K 3/18 C03C 17/32 C08J 3/20 WPI / L (QUESTEL)

Claims (7)

(57) [Claims] 1. An aqueous dispersion of a hydrophobic acrylic resin having a glass transition temperature in the range of 35 to 80 ° C., (b) an inorganic colloid sol, and (c) a monovalent electrolyte (excluding chlorine compounds). An antifogging agent composition which is an essential component and contains 0.01 to 30 parts by weight of the component (c) based on 100 parts by weight of the solid content of the component (b). 2. The method according to claim 1, wherein the hydrophobic acrylic resin of the component (a) is
(Meth) acrylic acid alkyl esters or (meth)
At least 60% by weight of a mixture of an alkyl acrylate and an alkenylbenzene, and a single polymer obtained by polymerizing 0 to 40% by weight of an α, β-ethylenically unsaturated monomer copolymerizable therewith. The antifogging agent composition according to claim 1, which is a coalesced or copolymerized product. 3. The antifogging composition according to claim 2, wherein the proportion of the component (c) is 0.01 to 10 parts by weight based on 100 parts by weight of the solid content of the component (b). 4. The composition according to claim 1, wherein the amount of the component (b) is from 0.5 to 4 based on the solid content of the component (a).
4. The antifogging agent composition according to any one of items 3 to 3. 5. The solid average particle diameter of the component (b) is 5 to 1
The antifogging composition according to any one of claims 1 to 4, wherein the composition has a particle size of 00mμ. 6. The antifogging composition according to claim 1, wherein the component (b) is a silica sol or an alumina sol. 7. An antifogging agent composition comprising the antifogging agent composition according to claim 1 and a crosslinking agent for a hydrophobic acrylic resin as the component (a).