JPS6228825B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has excellent anti-fog properties and abrasion resistance,
Moreover, the present invention relates to an antifogging coating composition for forming a coating film with excellent weather resistance. A disadvantage of conventionally used transparent materials such as plastics and inorganic glasses is that when the surface temperature falls below the dew point of the environment, they become cloudy and lose their transparency, causing great inconvenience. For this reason, coating methods for forming an antifogging coating film on the surface of transparent materials have been researched and various attempts have been made. For example, it is known to form a coating mainly composed of hydroxyethyl methacrylate polymer or polyvinyl alcohol, but all of the antifogging coatings that have been tried so far, including this one, only have antifogging properties. Although this has been met with some satisfaction, it has the drawbacks of being extremely easily scratched, having poor abrasion resistance, and poor weather resistance, so it has not been put to practical use yet. For this reason, the present inventors have conducted intensive research into a composition that can form a coating film that has antifogging properties as well as abrasion resistance and weather resistance.
By adding a vinyl polymer having an epoxy group, a polyhydric alcohol having an ethylene oxide chain, a curing catalyst, and optionally a crosslinking agent, especially a crosslinking agent containing an epoxy group, it has excellent antifogging properties and abrasion resistance. Moreover, it has been found that a coating film with excellent weather resistance can be obtained. That is,
The present invention is a copolymer of (A) a (meth)acrylic monomer having an epoxy group in its side chain and an alkyl (meth)acrylate containing a hydroxyl group, which has the general formula (In the formula, R ¹ and R ² each independently represent a hydrogen atom or a lower alkyl group, and X represents an alkyl group having an epoxy group.) Copolymer 20 containing at least 20% by weight of the repeating structural unit represented by
~75 parts by weight, (B) 25 to 80 parts by weight of polyhydric alcohol having an ethylene oxide chain, the total of (A) and (B) above.
This is an antifogging coating composition comprising 100 parts by weight as a main component, further containing a curing catalyst and, if necessary, a crosslinking agent, preferably a crosslinking agent containing an epoxy group. General formula used as component (A) of the present invention (In the formula, R ¹ and R ² each independently represent a hydrogen atom or a lower alkyl group, and X represents an alkyl group having an epoxy group.) A copolymer (including a cooligomer) containing a repeating structural unit is It can be obtained by copolymerizing a (meth)acrylic monomer having at least one epoxy group in the molecule as exemplified below and a hydroxyl group-containing alkyl (meth)acrylate described below. Specific examples of (meth)acrylic monomers having epoxy groups include glycidyl methacrylate and acrylate, β-glycidoxyethyl methacrylate and acrylate, 3,4-epoxybutyl methacrylate and acrylate, 4,5-epoxypentyl methacrylate, and Examples include acrylate. Moreover, hydroxyethyl methacrylate and acrylate, diethylene glycol monomethacrylate and acrylate, etc. can be used as the hydroxyl group-containing alkyl (meth)acrylate. Component (A) may be only a copolymer of an epoxy group-containing (meth)acrylic monomer and a hydroxyl group-containing alkyl (meth)acrylate; Copolymers of monomers such as methyl methacrylate and acrylate, ethyl methacrylate and acrylate, butyl methacrylate and acrylate are also possible. However, if the proportion of the repeating structural unit represented by the above general formula contained in component (A) is too small, the abrasion resistance of the coating will decrease.
The content is more preferably 40% by weight or more. In addition, considering component (A) from the viewpoint of its production, if you try to polymerize only the vinyl monomer having an epoxy group, it will tend to gel due to self-crosslinking. It is preferable to copolymerize it with other copolymerizable monomers. The polyhydric alcohol having an ethylene oxide chain used as component (B) of the present invention is a polyhydric alcohol having at least one chain (-CH ₂ CH ₂ O-) in the molecule. If the molecular weight of the polyhydric alcohol having ethylene oxide chains is too large, the reactivity of the hydroxyl groups will decrease, making curing difficult and sufficient film forming properties cannot be obtained. The molecular weight of the polyhydric alcohol with ethylene oxide chain is
It is preferably within the range of 100 to 3000, particularly preferably 200 to 2000. Typical examples of the polyhydric alcohol having an ethylene oxide chain that can be applied to the present invention include diethylene glycol and triethylene glycol with a molecular weight of 100.
Polyethylene glycol with a molecular weight of ~3000, preferably 200-2000, with the general formula HOCnH ₂ nOH (n=
3 to 10) diols with 1 to 10, preferably 1 to 7, ethylene oxide chains added to both ends, and polyhydric diols such as glycerin, trimethylolpropane, diglycerin, pentaerythritol, adonitol, sorbitol, and inositol. Alcohols in which an ethylene oxide chain is added to at least one hydroxyl group, and mixtures thereof can be used. Especially the following formula (In the formula, n ₁ to n _n are each independently an integer of 0 to 7, and at least two of them are integers of 1 or more, and m is an integer of 3 to 9.) A polyhydric alcohol having an oxide chain, especially in the above formula, n ₁ to n _n is 1 to
5 is preferred. In the present invention, the components (A) and (B) are used at a ratio of 20 to 75 parts by weight and 25 to 80 parts by weight, respectively (however, a total of 100 parts by weight), but more preferably 40 parts by weight each.
~70 parts by weight, preferably 30 to 60 parts by weight. If the amount of component (A) exceeds 75 parts by weight, that is, if the amount of component (B) is less than 25 parts by weight, the antifogging performance will be significantly reduced and at the same time a transparent and smooth film will not be obtained. Furthermore, if the component (A) is less than 20 parts by weight, that is, if the component (B) exceeds 80 parts by weight, the hot water resistance will be poor and the abrasion resistance will not be sufficient. Curing catalysts used in the present invention include catalysts capable of initiating ring-opening polymerization, such as perchloric acid, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, sulfonic acid derivatives, p-toluenesulfonic acid, boron trifluoride, and its electron donor. complex with. _SnCl4 , _ZnCl2 , _FeCl3 , _AlCl3 ,
Lewis acids such as SbCl ₅ and TiCl ₄ and their complexes. Organic acid metal salts such as sodium acetate, zinc naphthenate, cobalt naphthenate, zinc octylate, and tin octylate. Boufurated metal salts such as zinc borofluoride and tin borofluoride. Boric acid organic esters such as ethyl borate and methyl borate. Alkali such as sodium hydroxide and potassium hydroxide. Titanate esters such as tetrabutoxytitanium and tetraisopropoxytitanium. Metal acetylacetonates such as chromium acetylacetonate, titanyl acetylacetonate, aluminum acetylacetonate, cobalt acetylacetonate, and nickel acetylacetonate. n-butylamine,
Amines such as di-n-butylamine, tri-n-butylamine, guanidine, biguanide, and imidazole. Examples include ammonium perchlorate. Among these catalysts, ammonium perchlorate can be particularly preferably used. That is, when ammonium perchlorate is used, the pot life of the coating composition as a paint is long, the curing conditions such as baking curing temperature and time are practical, and the water resistance and adhesion of the coating film are particularly excellent. It is from. If the amount of curing catalyst added is too small, the time required for curing will be long, and if it is too large, it tends to worsen the water resistance or cause the coating film to become discolored. It is desirable to add 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, per 100 parts by weight of B) and the optional crosslinking agent. In the present invention, it is not necessarily necessary to further contain a crosslinking agent in addition to the component (A), the component (B), and the curing catalyst, but a crosslinking agent may be contained. In particular, by using a crosslinking agent containing an epoxy group as a crosslinking agent, the abrasion resistance of the coating obtained using the coating composition of the present invention can be further improved. Examples of the epoxy group-containing crosslinking agent used here include the following. Polyhydric phenols such as bisphenol A, bisphenol F, resorcinol and novolak resin, or polyphenols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerin, diglycerol, neopentyl glycol, trimethylolpropane, pentaerythritol, and sorbitol. polyglycidyl ethers obtained from polyhydric alcohols and epichlorohydrin, polyglycidyl esters obtained from epichlorohydrin and polybasic acids such as phthalic acid, hexahydrophthalic acid, and dimer acid, aniline, toluidine, 4,4'-diaminodiphenylmethane, and isocyanuric acid. Examples include polyglycidylamines obtained from amines such as acids and epichlorohydrin, and alicyclic epoxy resins such as cyclopentadiene dioxide and cyclohexene oxide. These compounds can be used alone or in a mixture of two or more. The amount of crosslinking agent, especially these crosslinking agents having epoxy groups, is preferably 3 to 80 parts by weight per 100 parts by weight of components (A) and (B), and more preferably 5 to 60 parts by weight. is desirable. Additionally, γ is added to the crosslinking agent containing the epoxy group.
Even if an organic silane compound having an epoxy group such as -glycidoxypropyltrimethoxysilane is further added and mixed, there is no problem in terms of performance, and a combination of these organic silane compounds is also included in the present invention. It is also possible to improve wettability by adding a surfactant to the antifogging coating composition, which is composed of (A), (B), a curing catalyst, and a crosslinking agent added as necessary. The surfactant is not particularly limited and conventionally available surfactants can be used, but polyoxyethylene type nonionic surfactants are particularly preferably used. Specifically, polyoxyethylene alkyl ether type R-O
(CH ₂ CHO−) _o H, polyoxyethylene alkylaryl ether type

[Formula] Polyoxyethylene alkylamine type R-NH (CH ₂ CH ₂ O-) _o H
and

[Formula] Polyoxyethylene alkylamide type R-CONH (CH ₂ CH ₂ O-) _o
H and

[Formula] Polyoxyethylene polyol ester type

[Formula] (where n ₁ to n ₃ are each independently an integer of 1 to 7, R ₁ to R ₃ are each independently hydrogen or an acyl group having 6 to 16 carbon atoms,
m is 0 or an integer from 1 to 9), polyoxyethylene sorbitan ester type Examples include nonionic surfactants such as. Before use, the antifogging coating composition of the present invention is usually diluted to a concentration suitable for application.
Examples of the solvent used for this dilution include alcohols, ketones, esters, ethers, cellosolves, halides, carboxylic acids, aromatic compounds, etc., and these may be used alone or in combination. It may also be used as a mixed solvent of the above. Among these, lower alcohols (e.g. methanol, ethanol, propanol, butanol), cellosolves (e.g. methyl cellosolve, ethyl cellosolve, butyl cellosolve), lower alkyl carboxylic acids (e.g. formic acid, acetic acid, propionic acid), aromatic compounds (e.g. toluene) , xylene) and esters (for example, ethyl acetate, butyl acetate), etc. are preferably used alone or as a mixed solvent. If necessary, a flow control agent may be added to the composition of the present invention in order to obtain a smooth coating film. A small amount of the flow control agent is sufficient, and the purpose can be achieved with an amount of 5% by weight or less based on the solid content of the composition. Coating with the composition of the present invention is carried out by a commonly used coating method such as dipping, spraying, roller coating, or flow coating at a temperature below the deformation temperature of the substrate for 15 minutes to 5 hours. By baking and hardening,
A coating film with good anti-fog properties, abrasion resistance, hot water resistance, adhesion and weather resistance can be obtained. In addition, this antifogging coating composition can also be easily colored using a coloring agent after being applied to a substrate and baked. As a coloring method, it is also possible to color the substrate coated with the antifogging coating composition in the gas phase using a vaporizable coloring agent, as described in the already filed Japanese Patent Application No. 35262/1986. Moreover, as described in Japanese Patent Application No. 77525/1983, which has also been filed, a substrate coated with the antifogging coating composition is coated with a coloring agent, a surfactant, and if necessary a solvent. It is also possible to color by contacting with a dye liquor in which the amount of active agent is 0 to 100% by weight, based on the total amount of surfactant and solvent. The preferred thickness of the coating film after applying the antifogging coating composition of the present invention to a substrate and baking is 1 to 40.
microns, more preferably 3 to 30 microns. If it is less than 1 micron, antifogging properties and abrasion resistance will not be sufficient, and if it is more than 40 microns, hot water resistance and adhesion will be poor. The composition of the present invention can be applied to plastic substrates such as glass, polycarbonate, polymethyl methacrylate, polystyrene, polyvinyl chloride, polyester, cellulose, etc., but it can be further strengthened by primer treatment if necessary. A coating film with adhesive properties can be obtained. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by these Examples. In addition, in the examples, the anti-fogging property was measured by measuring the sample kept at -10℃ at 22℃-60%.
Take it out in an RH atmosphere and observe whether there is any clouding. Abrasion resistance was evaluated by rubbing with a brass wire brush (Yoji type 4 line type) and examining the resistance to scratches as follows. A: No scratches even if rubbed strongly. B: Slight damage occurs when rubbed strongly. C: Even weak friction causes scratches. Hot water resistance was determined by immersing the sample in boiling water for 1 hour.
The condition of the paint film was examined. Examples 1 to 12 Comparative Examples 1 to 4 (1) Preparation of glycidyl methacrylate (60 parts by weight)-hydroxyethyl methacrylate (40 parts by weight) copolymer solution (A-1) 140 g of ethyl cellosolve, 36 g of glycidyl methacrylate, 24 g of hydroxyethyl methacrylate, Add 0.3g of azobisisobutyronitrile (AIBN) and cool while stirring gently.
Raise to 90℃. The process continues for about 4 hours while constantly blowing nitrogen. The resulting solution turned into a pale yellow liquid with a viscosity of approximately 90 CPS (molecular weight approximately 20,000), and a copolymer of glycidyl methacrylate and hydroxyethyl methacrylate was formed. (2) 3,4-epoxybutyl methacrylate (70
parts by weight) - Methyl methacrylate (15 parts by weight) -
Hydroxyethyl methacrylate (15 parts by weight)
Preparation of copolymer solution (A-2) 140 g of ethyl cellosolve, 42 g of 3,4-epoxybutyl methacrylate, 9 g of methyl methacrylate, 9 g of hydroxyethyl methacrylate
Add g and AIBN0.3g and bring to temperature while stirring gently.
Raise to 90℃. The process continues for about 4 hours or more while constantly blowing nitrogen. The resulting solution has a pale yellow color and a viscosity of approximately 80 CPS (molecular weight approximately
18000), and a copolymer of 3,4-epoxybutyl methacrylate, methyl methacrylate, and hydroxyethyl methacrylate was formed. (3) Preparation of glycidyl methacrylate (15 parts by weight) - ethyl methacrylate (50 parts by weight) - hydroxyethyl methacrylate (35 parts by weight) copolymer solution (A-3) 140 g of ethyl cellosolve, 9 g of glycidyl methacrylate, 30 g of ethyl methacrylate, hydroxyethyl Methacrylate 21g and AIBN0.3
Add g and raise the temperature to 90℃ while stirring gently. While continuously blowing nitrogen,
Continuation of time. The resulting solution is pale yellow in color and has a viscosity of approx.
It becomes a liquid of about 100 CPS (molecular weight about 20,000),
A copolymer of glycidyl methacrylate, ethyl methacrylate and hydroxyethyl methacrylate was formed. (4) Polyhydric alcohols (B-1 to B-4) having ethylene oxide chains. Those shown in Table 1 were used.

[Table] (5) Crosslinking agent containing epoxy group (C-1 to C-
7). Those shown in Table 2 were used.

[Table] (6) Curing catalyst. Ammonium perchlorate (D-
1), aluminum acetylacetonate (D
-2) was used. (7) Surfactants. Among nonionic surfactants, polyoxyethylene alkylaryl type surfactants (Liponox NCN manufactured by Lion Oil Co., Ltd.) (E-
1) Polyoxyethylene sorbitan ester type activator (Nitsusan Nonion, manufactured by NOF Corporation)
LT-221) (E-2) was used. (8) Preparation of paint The above-mentioned epoxy group-containing polymer (A-1
~A-3), a polyhydric alcohol having an ethylene oxide chain (B-1 to B-4), a curing catalyst (D-1 to D-2), and optionally a crosslinking agent containing an epoxy group (C -1 to C-7) and surfactants (E-1 to E-2) in the proportions shown in Table 3, and then add a small amount of flow control agent so that the solid content is 20 to 50% by weight. Diluted with ethyl cellosolve. (9) Painting The above paint was applied by dipping to a 3 mm thick diethylene glycol bisallyl carbonate plate that had been cleaned in advance, and cured by heating at 130°C for 1 hour. The performance results of the coating film are summarized in Table 3. Example 13 In Example 3 of Table 3, C-3 was used as a crosslinking agent.
Instead of using 25 parts by weight of C-3, 12.5 parts by _{weight of a hydrolyzate of γ-glycidoxypropyltrimethoxysilane (calculated as RSiO 1.5 )}
A paint prepared in the same manner as above was applied by dipping onto a 3 mm thick diethylene glycol bisallyl carbonate plate that had been cleaned in advance, and cured by heating at 130°C for 1 hour. I let it happen. The coating film had good antifogging properties, abrasion resistance, and hot water resistance. Example 14 Anthraquinone disperse dye Sumikalon Blue E- was prepared by crushing an antifogging base material obtained in exactly the same manner as in Example 4 sufficiently finely in a mortar.
Maintain a distance of approximately 50 mm from the colorant container containing FBL (product name: Sumitomo Chemical Co., Ltd.).

[Table] Next, isolate the inside of the bell jar from the outside air, reduce the pressure inside to 0.5 Torr with a vacuum pump, then turn on the heater of the colorant container and raise the temperature to 200℃.
It was held for 10 minutes to allow the colorant to evaporate. The anti-fog base material set in this bell gear is rotated at a rate of 60 revolutions per minute in a colorant gas to prevent uneven coloring density, thereby obtaining a base material having a uniformly colored anti-fog colored coating on one side. I was able to do that. The base material having this antifogging colored coating has the same antifogging properties, abrasion resistance, and hot water resistance as in Example 7, and at the same time, it has passed the color fastness test against carbon arc lighting (JIS L-
0842-1971) (hereinafter referred to as fade test) It had fastness with almost no fading even after 200 hours. Example 15 An antifogging base material obtained in exactly the same manner as in Example 7 was treated with a polyoxyethylene alkylaryl type surfactant (trademark Liponox manufactured by Lion Oil Co., Ltd.).
NCO) 90g and anthraquinone disperse dye (trademark Sumikalon Blue E- manufactured by Sumitomo Chemical Co., Ltd.)
By immersing the base material in a dye bath consisting of 10 g of FBL at 95°C for 5 minutes, it was possible to obtain a base material having a uniform blue transparent anti-fog colored coating. The base material having this anti-fog colored coating has the same anti-fog properties, abrasion resistance, and hot water resistance as in Example 6, and at the same time, it has undergone a fade test.
It had fastness with almost no fading even after 200 hours.

Claims (1)

[Scope of Claims] 1 (A) A copolymer of a (meth)acrylic monomer having an epoxy group in its side chain and an alkyl (meth)acrylate containing a hydroxyl group, which has the general formula (In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a lower alkyl group, and X represents an alkyl group having an epoxy group.) Copolymer 20 containing at least 20% by weight of the repeating structural unit represented by
~75 parts by weight, (B) 25 to 80 parts by weight of polyhydric alcohol having an ethylene oxide chain, the total of (A) and (B) above.
An antifogging coating composition containing 100 parts by weight as a main component and further containing a curing catalyst. 2 In addition to the components (A) and (B) above and the curing catalyst, the crosslinking agent containing an epoxy group is the sum of the above (A) and (B).
The antifogging coating composition according to claim 1, which is contained in an amount of 3 to 80 parts by weight per 100 parts by weight. 3 The polyhydric alcohol having an ethylene oxide chain has the general formula (In the formula, n ₁ to n _n are each independently an integer of 0 to 7, and at least two of them are integers of 1 or more, and m is an integer of 3 to 9.) The antifogging coating composition according to claim 1 or 2. 4. The curing catalyst is ammonium perchlorate and is contained in an amount of 0.05 to 20 parts by weight per 100 parts by weight of the total of component (A), component (B), and optionally added crosslinking agent. -Anti-fog coating composition according to item 3.