JPS6079071A - Protective coating agent - Google Patents

Abstract

PURPOSE:To provide a protective coating agent capable of forming a coating film which has an excellent protecting effect and does not cause Moire fringe, discoloration, glittering, etc., by blending an organohydroxysilane, colloidal silica and a solid content modifier. CONSTITUTION:A protective coating agent having a solid content of 1-40wt% is obtd. by blending 5-200pts.wt. colloidal silica having an average particle size of 5-150mmu and a pH of 8-9 and a solid content modifier (e.g. lower aliph. alcohol, ethylene glycol derivative or diacetone alcohol) with 100pts.wt. organohydroxysilane (or partial condensate) of the formula [wherein R<1> is methyl, ethyl, proplyl, phenyl (5-50% thereof is phenyl)] such as phenyltrimethoxysilane.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a protective coating agent used for modifying and improving the surface condition and optical properties of a substrate, and more particularly, the present invention relates to a protective coating agent used for modifying and improving the surface condition and optical properties of a substrate. B,'8 No interference fringes or color appear when used to modify or protect the surface.
! Regarding coating agents.

[Technical background of the invention and its problems] In recent years, transparent plate glass has been replaced by molded bodies made of transparent plastics, which take advantage of their advantages such as light resistance, easy build-up, and excellent impact resistance. It is used in a wide range of applications, including lenses for optical equipment, window glass for buildings, and window glass for transportation vehicles such as trains and automobiles.

Polycarbonate resin is known as one of the most commonly used materials among such transparent plastics. This resin has a refractive index as high as 1.584 among transparent plastics, and that of glass is 1,50 to 1,52.
Since it has a high value even compared to , it is expected to be used as a substitute for glass in applications such as lenses. Furthermore, this resin has high impact resistance and heat deflection temperature, and is excellent in dimensional stability, workability, and self-extinguishing properties. However, on the other hand, since the surface hardness is low, it is easily susceptible to abrasions and scratches, and its resistance to petroleum solvents and the like is also poor, so it has problems in that its transparency is easily impaired.

In response to these problems, various attempts have been made to improve surface properties such as surface hardness and solvent resistance. For example, coating agents have been applied to the surface of polycarbonate resin. ing. These coating materials not only provide scratch resistance and chemical resistance to transparent putestink, but also provide IlI'lJ weatherability and antistatic properties, and further increase light transmittance and improve transparency. It is something that makes you Melamine resins, curable acrylic resins, polyester resins, polyurethane resins, silicone resins, etc. have been studied as surface hardening coating compositions used in this field, and some of them have been put into practical use. .

However, when a plastic surface is coated with these surface-curing coating M1 compositions, there is a large difference in the refractive index of the cured coating from the refractive index of the plastic material to which it is coated, so that fringes may occur due to light interference phenomena. Since patterns and colors are expressed on the substrate surface, optical properties become two issues.

In order to solve these problems, a method of increasing the thickness of the coating material has been adopted; however, it is difficult to completely eliminate the stripes; The mechanical properties of the plastic material, especially the impact resistance and flexibility of the plastic material, are reduced, and the ease of use of the surface coating composition and the workability during the coating process are reduced. or,
As another method, it has been proposed to make the refractive index of the resin forming the film or skin 11R close to that of the substrate to be coated. One such technique is a method of coating a substrate surface with a thin layer of inorganic material, and vacuum deposition methods, moxibustion battering methods, electron beam methods, and the like are used. However, these techniques have many problems when applied to plastic materials. That is,
Since plastic materials generally have insufficient heat resistance, they cannot withstand the above-mentioned coating process, and in some cases, the substrate itself may decompose, melt, thermally deform, optically distort, etc. Furthermore, the adhesion to the substrate is generally poor. Furthermore, coating with an inorganic layer significantly reduces the impact resistance and flexibility of the plastic material. In this way, the optical properties of the plastic material are maintained or improved,
A coating agent or coating technique that has good adhesion to a substrate and is useful for protecting the substrate has not yet been obtained.

[Development ψ) Purpose of the present invention] The purpose of the present invention is to solve the problems described in , to effectively protect the substrate when applied to a substrate such as plastic, and to
Sixth, it is an object of the present invention to provide a surface-curing protective coating agent that does not cause interference fringes, coloring, glare, etc. after application.

[Summary of the Invention] The protective coating agent of the present invention has the following formula: represents a group 17, R1
5 to 50 mol% of the group is a phenyl group, and the remainder represents at least one monovalent group selected from the group consisting of a methyl group, an ethyl group, and a propyl group. ) or a partial condensate thereof, (B) colloidal silica, and (G) solid content wA moderator, characterized in that the solid content is 1 to 40% by weight. It is.

In the following, the invention will be explained in more detail.

The organohydroxysilane (A) used in the present invention has the formula: R' 5i(OR2) 3 (wherein R
1 has the same meaning as above, and R2 represents a group selected from the group consisting of a methyl group, an ethyl group, and a propyl group. The organohydroxysilane is obtained by hydrolyzing the organoalkoxysilane in an acidic water-alcohol mixture or an aqueous dispersion of colloidal silica (B). Examples of such organoalkoxysilanes include the following compounds.

3CH5l(QC2)15)3, CHS+(0(l)+3)3, 3CHS+(QCH), C)l5l(QC)13)
3.3 373 25 C)l 5i(OCH), CH5i(QC)+3)3
The organohydroxysilane of 37 33 65 CH5i (QCH) 65 253 (A) includes those in which the alkoxy group of the above-mentioned organoalkoxysilane is V-substituted with a hydroxy group. Of the 4'iX represented by R1 of the organohydroxysilane, 5 to 50
The mole percent must be phenyl groups. By blending an organohydroxysilane having a phenyl group, the refractive index of the protective coating agent increases and the adhesion to the substrate improves. If the amount of phenyl groups is less than 5 mol %, the refractive index will not be very high and good adhesion to the substrate will not be achieved. On the other hand, if it exceeds 50 mol%, the rate of increase in the refractive index as the phenyl group content increases slows down, and the effect of its addition decreases, which also reduces the dispersion stability of each component of the protective coating agent. As a result, the cured film tends to become cloudy, and the pot life of the protective coating agent is shortened.

The colloidal silica (B) used in the present invention imparts abrasive properties to the coating agent and improves the deposition properties of the anti-reflective gold and alcoholic substances formed in the coating layer. It is an ingredient that is blended for. The average particle size of such silica is preferably 5 to 150 m pot,
More preferably, it is 5 to 30 ml. If the average particle size of silica is less than 5 mμ, the performance required for practical use will not be sufficient, while if it exceeds 150 mμ, the abrasion resistance of the resulting coating will be reduced.

Such colloidal silica is formulated as a colloidal dispersion upon its use. Such a dispersion has a pH of
(hydrogen ion concentration) is preferably in a weak basic range of 8 to 9, and the silica content in the dispersion is 15 to 4.
It is preferably 0 double star%, more preferably 20~
It is 30% by weight.

If the pH is less than 8, the hardness of the resulting film will be low, while if it exceeds 9, it will be difficult to set the conditions for the hydrolysis reaction of organoalkoxysilane. Furthermore, if the silica content in the dispersion is less than 15% by weight, the silica blending efficiency will be poor and the amount of water introduced into the system will increase.
Contains phenyl group, 71 Knee + Kame, 106 Yuzumu and Han T
1st system Godai Haha Ayu # Neutralization decreases. On the other hand, if it exceeds 40% by weight, it becomes difficult to manufacture the dispersion itself.

When blending component (B), it is preferable that 5 to 200 parts by weight of silica be added, more preferably 10 to 60 parts by weight, per 100 parts by weight of the organoalkoxysilane of component (A) during hydrolysis. be. For example, when component (B) is a colloidal aqueous dispersion of silica with a silica content of 20% by weight to 1IX%, the amount of organoalkoxysilane that is the precursor of component (^) is 100ji! This corresponds to blending about 20 to 350 parts by weight of the silica dispersion liquid per part of the silica. (B) The amount of component is 5tF
! If the thickness is less than 100 mm, the abrasion resistance of the coating will be poor, and it will be difficult to deposit a metal oxide for anti-reflection. On the other hand, if it exceeds 200 parts by weight, the dispersion stability of each component of the protective coating agent will be low, causing cloudiness in the film after curing, and the pot life of the protective coating agent will be shortened. The adhesion between the cured film and the substrate is significantly reduced.

The solid content regulator (G) used in the present invention adjusts the solid content of the protective coating agent of the present invention, and
This improves the dispersion stability and further improves workability, making it easier to obtain a transparent film.

Examples of such solid content regulators include methanol, ethanol, propatool, inpropatool, n-
lower aliphatic alcohols such as butanol and inbutanol; and ethylene glycol derivatives such as ethylene glycol, ethylene glycol monoethyl ether, and acetic acid ethylene glycol monoethyl ether; and diacetone alcohol. One or more of these may be used.

Among these, at least one selected from the group consisting of impropatol, n-butanol, imbutanol, acetic acid ethylene glycol monoethyl ether, and diacetone alcohol is particularly used because it provides good workability. It is preferable to do so.

The solids content of the protective coating of the present invention is 1 to 40% by weight. When storing the protective coating agent, adjust the solid content to 10 to 40% by weight and store it.
It is preferable to further dilute it with a solid content regulator if necessary before use. If the solid content exceeds 40% by weight, the dispersion stability will be significantly reduced, workability will be poor, and the resulting film will be thick and prone to cracking. On the other hand, if it is less than 1% by weight, a uniform and suitable film thickness cannot be obtained when dip coating is performed.

To make the protective coating of the present invention.

First, the organoalkoxysilane is hydrolyzed in a water-alcohol mixture or in a colloidal aqueous dispersion of silica. This hydrolysis may be performed by dissolving a colloidal dispersion of silica in the case of further coating the protective coating of the present invention with another surface hardening coating composition and in the case of vapor deposition of antireflective metal oxides. What you do inside is tl
It's so cute.

The hydrolysis conditions are preferably carried out by maintaining the liquid temperature at 10 to 40°C and stirring under the same pressure for 4 to 30 hours, and more preferably by stirring the reaction at a liquid temperature of 25 to 35°C for 6 to 24 hours. It is to let

The organoalkoxysilane is hydrolyzed in the water-alcohol mixture as described above, and at this time, various inorganic acids, organic acids, or hydrolysis catalysts such as aluminum chelate may be used as necessary. Such hydrolysis catalysts include, for example, hydrochloric acid, @acid, acetic acid, acetic anhydride,
Acids such as chloroacetic acid, propionic acid, oxalic acid, malonic acid, dimethylmalonic acid, maleic acid, glycolic acid, glutaric acid, citric acid, benzoic acid, toluene sulfonic acid, aluminum diacetylacetonate, aluminum ethyl acetate bisacetyl Examples thereof include aluminum chelates such as acetonate, aluminum bisethyl acetate acetylacetonate, aluminum di-n-butoxymonoethyl acetoacetate, and aluminum diisopropoxide monomethylacetoacetonate.

Among these, it is particularly preferable to use acetic acid or acetic anhydride.

The amount of the hydrolysis catalyst used is preferably 0.1 to 15 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the colloidal aqueous silica dispersion.

Then, in order to remove excess water from the colloidal aqueous dispersion of silica, a lower aliphatic alcohol is added and the condensation reaction of the hydrolyzate is azeotropically distilled off in an uncontrolled manner. Any lower aliphatic alcohol may be used as long as it is azeotrope with water, and examples thereof include methanol, ethanol, propatool, impropatol, n-butanol, imbutanol, etc. One or more selected from the group consisting of: Such water removal can be carried out, for example, by keeping the liquid temperature at 20 to 70°C and applying a pressure of 20 to 300 m+mH.
Stripping is preferably carried out under a reduced pressure of
The conditions are a C1 pressure of 30 to 50 maHg.

The amount of lower aliphatic alcohol added may be sufficient to azeotropically distill off excess water originating from the silica colloidal dispersion, and should be 2 parts by weight per 100 parts by weight of water in the dispersion.
The amount is preferably 1 part by weight or more, and if it is desired to increase the degree of water distillation, a large amount of alcohol may be added in several portions. If the amount of the lower aliphatic alcohol added is less than 21 parts by weight, it will be difficult to suppress or control the condensation reaction of organohydroxysilane or its partial condensate during azeotropy, resulting in a decrease in the hardness and transparency of the resulting film. I may invite you.

After azeotropic distillation of excess water originating from the colloidal aqueous dispersion of silica, the organic solvent as a solid content regulator is added to adjust the solid content of the composition to 10 to 40% by weight. do. The water content in the composition thus obtained is preferably 20% by weight or less, more preferably 10% by weight or less. At this time, the azeotropic alcohol cannot be used even if it remains.

The thus obtained protective coating agent of the present invention may further contain a leveling agent, a thickener, a dye,
Even if various additives such as ultraviolet absorbers are added, there will be no difference.

In order to obtain a cured film by applying the protective coating agent of the present invention onto a substrate, it is possible to employ, for example, the following method.

That is, it is preferable to apply the protective coating agent of the present invention to a substrate by a commonly known method such as coating, spray coating, or dip coating to a thickness of about 0.05 to 20 g, more preferably. is 0.1 to l.

Apply to desired thickness. Then, heat at 80"C for 3 hours to 1
By heating at 20°C for about 1 hour, a film having good adhesion to the substrate can be obtained. If it is desired to cure under milder conditions, the curing reaction can be carried out by adding a silanol condensation catalyst. Examples of such condensation catalysts include 1. For example, alkali metal carboxylates such as sodium acetate and potassium formate; amine carboxylates such as dimethylamine acetate, ethanolamine acetate, and dimethylaniline formate; quaternary carboxylates such as tetramethylammonium acetate; Ammonium carboxylate; Carboxylic acid metal salts such as soot naphthenate; Amines such as triethanolamine and pyridine; Alkali hydroxides such as sodium hydroxide and ammonium hydroxide; γ-aminopropyltriethoxysilane, γ-(N
Examples include amine-based silane coupling agents such as -β-aminoethyl)aminopropyltrimethoxysilane, aluminum chelate compounds, and one or more selected from the group consisting of these.

The amount of these condensation catalysts added is appropriately selected depending on the curing conditions, but is 0.05 to 5,
It is preferably 0% by weight, more preferably 0.0% by weight.
It is 8 to 0.15% by weight. By adding the above-mentioned condensation catalyst, the protective coating agent of the present invention cures on the substrate at a temperature of about 65 to 120"C in a relatively short time, and forms a transparent film with excellent adhesion to the substrate. It is something to give.

Substrate materials to which the protective coating of the present invention can be applied include, for example, transparent to opaque plastics, metals, wood, leather, glass, and ceramics. Among these, examples of plastic materials include acrylic resin, polyester resin, polyimide resin, polyamide resin, acrylonitrile-butadiene copolymer resin, polyvinyl chloride resin, polyethylene resin, polycarbonate resin, and metal materials. Examples include aluminum, sprocketed chromium alloy, and the like. At this time, if adhesion to the substrate is a problem, it is possible to apply the coating by applying a primer treatment to the substrate surface in advance. Therefore, it is possible to apply the coating to the surface of almost all solid materials. It is possible. The coating agent of the present invention is particularly useful as a coating agent for polycarbonate resins and acrylic resins, and has extremely good adhesion to acrylic resins after one application. It is possible to form a film.

[Effects of the Invention] The skin obtained by applying the protective coating agent of the present invention is transparent, has excellent heat resistance and impact resistance, has excellent adhesion to the substrate, and has a high refractive index. It has the following. Furthermore, interference fringes and coloring phenomena due to the coating thin film applied to the substrate do not occur.

The reason why the coating obtained using the protective coating agent of the present invention does not cause interference fringes or coloring phenomena is considered to be as follows. That is, in general, when transparent thin films with different refractive indexes come into contact with a transparent substance, if there is a large difference in their refractive indexes,
They cause stripes and coloring phenomena due to light interference. By blending the protective coating agent of the present invention with an organohydroxysilane having a phenyl group, it is possible to adjust the refractive index of the formed film over the range of 1.44 ft to 1.530, so it can be used as a substrate. By selecting a composition that reduces the difference in refractive index depending on the refractive index of the material, interference fringes and the like can be prevented.

Furthermore, the film formed by the protective coating agent of the present invention can be further coated with a surface hardening coating composition or a metal compound for antireflection can be deposited to improve optical properties and The present invention provides a surface coating treatment agent that is excellent in both substrate protection properties.

[Examples of the Invention] The present invention will be explained in more detail with reference to Examples below. In addition, in the following examples and comparative examples, parts are parts by weight, and %
respectively mean % by weight.

Example 1 30.3 parts of methyltriethoxysilane, 1.78 parts of phenyltrimethoxysilane, 30.0 parts of colloidal silica (aqueous colloid liquid with 20% silica content, average particle size 5 to 20 mg) manufactured by Kochi Inguri Co., Ltd.
A mixture of 1 part and 0.2 part of acetic anhydride was placed in a glass flask, and the hydrolysis reaction was carried out while maintaining the temperature at 20 to 35°C and stirring for 16 hours. Next, 27.9 parts of isobutyl alcohol was added as a co-extracting alcohol, and after distilling off part of the water and alcohol originating from colloidal silica under a reduced pressure of 20 to 70 mmHH at a temperature of 20 to 50°C, solid Inbutanol 3 as a regulator
6 parts were added to obtain a processing agent (sample number 1) containing 30% solid content regulator.

In the same operation as above, the type and amount of organoalkoxysilane, azeotropic alcohol and solid content 1JRPrI
Eight types of coating agents (sample numbers 2 to 9) according to the present invention were obtained in the same manner except that the type and amount of the agent were changed as shown in Table MS1.

Comparative Example 1 1 Coating: 37 parts of methyltriethoxysilane, colloidal silica (
30 parts of the same material as in Example 1) and 0.0 parts of acetic anhydride.
The mixture consisting of two parts was placed in a flask and the following Example 1 was prepared.
A comparative coating agent (sample number 10) with a solid content concentration of 30% was obtained in the same manner as above.

Next, five types of comparative coating agents (sample numbers 11 to 15) were obtained in the same manner as in Example 1, except that the type of alkoxysilane and the amount of colloidal silica were changed as shown in Table 1. .

Furthermore, in the same manner as in Example 1, three types of comparative coating agents (sample numbers 16 to 18) were obtained using the alkoxysilanes and colloidal silicas shown in Table 1.

Example 2 The nine types of protective coating agents (sample numbers 1 to 9) prepared in Example 1 were applied to an acrylic resin plate (trade name: Niacrylite, manufactured by Mitsubishi Rayon Co., Ltd.), diethylene glycol bis Allyl carbonate (product name: C,
R-39, manufactured by Pittsburgh Puto Glass Co., Ltd.) by cast polymerization (hereinafter simply referred to as "polymer sheet"), polycarbonate plates (trade name: Nilexane, manufactured by General Electric Company), and glass plates. Applied using flow coating method, acrylic resin board was e o 'c for 3 hours, other test boards! A cured film was obtained by heating for 20'0÷1 hour. A pretreatment liquid (trade name: PHI3 +, manufactured by Toshiba Silicone Co., Ltd.) was applied to the surfaces of the acrylic resin plate and the polycarbonate plate in advance. Further, a pretreatment liquid (trade name -XP83-301, manufactured by Toshiba Silicone Co., Ltd.) was applied in advance to a polymer plate prepared by polymerizing diethylene glycol bisallyl carbonate.

Comparative Example 2 1 Using the nine types of comparative coachib agents (sample numbers 10 to 18) obtained in Comparative Example 1, acrylic resin plates and polymer plates were prepared according to the method shown in Example 2. ,
It was applied onto a polycarbonate plate and a glass plate by a flow coating method and cured by heating.

In addition, 11 cured skins obtained from comparative coating agents (sample numbers 17 and 18) developed cloudiness and could not obtain sufficient light transmittance.

Example 3 Good 1st grade Among the test pieces obtained in Example 2 and Comparative Example 2,
Regarding the cured film obtained by applying each coating agent to a polycarbonate plate, the following strip 4'
A performance test of the cured film was conducted using 1. The results are shown in Table 2.

Appearance two-sight test. Checked for abnormalities such as discoloration, cranks, and flow marks.

Adhesion: Number of remaining squares after three times of base tape peeling test.

Warm water resistance: Soaked in warm water at 280℃ for 500 minutes.

Abrasion resistance: Measured haze value after 50 cycles of wear using EiOrpm using a standard wear ring CS-+6 with a load of 500g using a Ronitary Absorber (manufactured by Toyo Seiki Co., Ltd.).

Thermal shock resistance knee 30℃ x 3hr+ + 12 (1℃
One cycle was x 3 hours, and the presence or absence of any abnormalities in the film was checked after three cycles.

Light transmittance: Measure the total light transmittance (when covered with a polycarbonate plate).

Refractive index: Calculated value based on measurements of light reflection properties.

Metal oxide vapor deposition WA adhesion: ZrOCeO, Nd2O
A mixed oxide consisting of 3 to 1 was heated to 2,500° C. in a vacuum of 10-2 Torr to evaporate to obtain a deposited film.

After being left in a constant temperature and humidity chamber at a temperature of 65° C. and a humidity of 95% R1 for 24 hours, the adhesion of the deposited film was examined by a cross-cut method.

Example 4 Among the test pieces obtained in Example 2 and Comparative Example 2,
The cured film obtained by applying the coating agent of sample number 1-te was visually observed for the appearance of interference fringes on each substrate. The results are shown in Table 3.

Example 5 The chemical resistance and solvent resistance of each sample of the protective coating agent according to the present invention coated on a polycarbonate plate with sample numbers 1 to 9 was investigated by immersing it in various test solutions for 24 hours. Furthermore, for stain resistance, various detergents, oils, cosmetics, insecticides, etc. were attached to each test plate.
After 0 minutes, it was wiped off with filter paper and the degree of stain removal was examined. The results are shown in Table 4.

As is clear from the results in Table 4, the protective coating agent of the present invention does not produce interference fringes when applied to a substrate, and has excellent heat resistance, impact resistance, and excellent substrate properties. It was confirmed that the adhesiveness was as follows.

Claims (1)

[Claims] 1. (A) The following formula: % formula % () (wherein RI represents a group selected from the group consisting of a methyl group, an ethyl group, a propyl group, and a phenyl group;
~50 mol% is a phenyl group, and the remainder represents at least one monovalent group selected from the group consisting of a methyl group, an ethyl group, and a propyl group. ) Organohydroxysilane or a partial condensate thereof, (B) colloidal silica, and (C) a solid content regulator, and the protective coating agent has a solid content of 1 to 40% by weight. . 2. The protective coating agent according to claim 1, wherein the amount of silica in (B) is 5 to 200 parts by weight based on 100 parts by weight of (A). 3. The average particle size of the siloidal silica (B) is 5 to 150
The protective coating agent according to claim 1, which is mJL. 4. The protective coating agent according to claim 1, wherein (B) has a pH of 8 to 9. 5. The protective coating agent according to claim 1, wherein the silica content in (B) is 15 to 40% by weight.