JPH04175309A - Production of aqueous silicone graft copolymer - Google Patents

Abstract

PURPOSE:To obtain a copolymer desirable for a coating agent excellent in adhesion to a substrate, strengths and film forming properties by reacting a graft copolymer obtained by copolymerizing three specified radical- copolymerizable components with a base. CONSTITUTION:The purpose aqueous silicone graft copolymer is obtained by reating a copolymer of an acid value of 30-260mgKOH/g of resin, obtained by copolymerizing the following radical-copolymerizable components (A), (B) and (C), with a base. Component (A) is a macromonomer prepared by introducing a (meth)acryloyl group into one end of a silicone, component (B) is an alpha, beta-ethylenically unsaturated carboxylic acid, and component (C) is a radical- polymerizable monomer other than components (A) and (B). Because the aqueous graft copolymer can impart the properties of silicone to a surface and has the function of the trunk polymer part, it can give a coating film excellent in water resistance, solvent resistance, weathering resistance, lubricity, mold releasability and adhesion, can be used in the form of a nontoxic aqueous organic solvent-free solution free from fire hazard and therefore is useful in respect of the prevention of environmental pollution and the saving of resources.

Description

[Detailed Description of the Invention] (a) Purpose of the Invention [Field of Industrial Application] The present invention exhibits the properties of silicone, has excellent adhesion to objects to be coated, strength, etc., and has excellent film-forming properties. It relates to a coating composition that has weather resistance, lubricity, mold releasability, water repellency, heat resistance, and stain resistance, and can be used in the form of an aqueous solution with less fire risk due to organic solvents and less toxicity. It is suitable as a coating material for the following purposes.

[Conventional technologies and their problems] Various silicone coating agents have been developed as coating agents that impart properties such as lubricity, mold releasability, water repellency, and heat resistance to the surface of substrates. Known examples include silicone alkyd varnish, silicone epoxy varnish, silicone acrylic varnish, silicone polyester varnish, and silicone urethane varnish.

However, the above-mentioned silicone varnish does not have sufficient adhesion to the object to be coated, and the current situation is that a primer is used in combination. In addition, in the silicone varnish mentioned above,
If the content of noricorn is reduced for the purpose of improving adhesion, the lubricity and mold releasability will deteriorate, and in general, silicone-based coatings have excellent adhesion to the object to be coated and excellent film strength. It has been extremely difficult to achieve both the properties of silicone, especially lubricity and mold releasability.

As a means to solve the above problems, a graft copolymer coating agent has been proposed that has silicone as a branch component and an alkyl acrylate copolymer as a main component (
JP-A-60-123518, JP-A-63-227
670). The above-mentioned coating agent is mainly composed of a silicone-based graft copolymer system consisting of a trunk polymer that has adhesion to the object to be coated and a silicone branch polymer, so it has physical properties related to adhesion and film strength, and lubricity and It has both physical properties related to mold release, and is expected to be used as weather-resistant paints, various plastic films, and surface protection materials for molded products.

However, all of the silicone-based graft copolymer coating agents mentioned above require the use of organic solvents, and in order to meet the demands of the times for pollution-free and resource-saving, they must be used in aqueous solutions rather than solvent-based coatings. There has been a strong desire for a silicone-based graft copolymer that can be used.

(B) Structure of the Invention [Means for Solving the Problems] The present inventors have arrived at the present invention as a result of intensive studies to solve the above-mentioned problems.

That is, the first invention of the present invention is a graft copolymer of a resin with an acid value of 30 to 260 mgKOH/g, obtained by copolymerizing the following radical copolymerization components (A), (B), and (C), with a base. A method for producing an aqueous silicone-based graft copolymer characterized by reacting (A) a macromonomer having a (meth)acryloyl group at one end of silicone (B) an α,β-ethylenically unsaturated carboxylic acid; (C) Radical polymerizable monomer other than the above (A) and (B) Also, in the second invention, the radical polymerizable component (C) is (meth)
This is an aqueous coating agent made of an aqueous silicone-based graft copolymer obtained by the above production method, which is a monomer mixture containing alkyl acrylate or hydroxyalkyl (meth)acrylate as a main component.

The present invention will be explained in more detail below.

[Production of silicone macromonomer] The silicone macromonomer used in the present invention is a silicone macromonomer having a methacrylic group at its terminal, and preferably has a number average molecular weight of 1°000 to 50,000.

When the number average molecular weight of the macromonomer is less than 1.000, it is difficult to exhibit properties derived from silicone, such as lubricity, mold releasability, and weather resistance. If it is above, the copolymerizability of the macromonomer will be poor, unpolymerized silicone will likely remain, and the silicone will not be water-soluble. The number average molecular weight in the present invention is a polystyrene equivalent number average molecular weight determined by gel permeation chromatography.

Furthermore, as the polymerizable group of the macromonomer, a methacryloyl group is more preferable.

The macromonomer can be produced by the method shown below. For example, a method using an anionic polymerization method involves reacting a living polymer formed by anionically polymerizing a cyclic siloxane using lithium trialkyl silate as an initiator and a vinyl polymerizable silicone compound shown in the table below. There is a method for producing silicone macromonomers (Japanese Unexamined Patent Publication No. 78236/1983).

[A fleet of vinyl polymerizable silicone compounds] CH2=C
-C0O-(CH2) l-(0)m-(CH2)3-
3i(CH3)2-CI (wherein R3 is hydrogen or a methyl group, m is 0 or 1, 1 is an integer from 0 to 2 when m=o, and 2 when m=■).

In addition, as a manufacturing method using a condensation reaction, JP-A No. 5
Publication No. 8-167606 and JP-A-60-123518
In the publication, there is a method for producing a silicone-based macromonomer obtained as a condensation reaction product of a terminal silanol group-containing noricone and a residual silicon compound.

[Silicone-based graft copolymer] The silicone-based graft copolymer in the present invention is obtained by copolymerizing the silicone-based macromonomer, α, β-ethylenically unsaturated carboxylic acid, and other radically polymerizable components. It is a graft copolymer with an acid value of 30 to 260 mgKOH/g resin.

The preferred amount of silicone macromonomer used in radical copolymerization to obtain a graft copolymer is 0.5 to 6,000,000 based on the total amount of all monomers used in the copolymerization.
It is 0% by weight, more preferably 2 to 50% by weight.

If the amount of the macromonomer is less than 0.5% by weight, the properties of silicone such as lubricity and mold releasability will not be sufficiently expressed, while if it exceeds 60% by weight, it will cause problems during polymerization or graft copolymerization. Phase separation occurs easily during storage, making it difficult to obtain a stable solution and making it difficult for the graft copolymer to become water-soluble.

Next, the above α,β-ethylenically unsaturated carbonic acid will be explained.

As the α,β-ethylenically unsaturated carboxylic acid in the present invention, acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc. are used. The amount of α, β-ethylenically unsaturated carboxylic acid used is 30 to 260 mg when the acid value of the graft copolymer is 30 to 260 mg.
Use the amount that gives KOH/g resin. The amount of α, β-ethylenically unsaturated carboxylic acid used that gives such an acid value, expressed in weight % based on the total amount of all radically polymerizable components subjected to polymerization, varies depending on the type of unsaturated carboxylic acid used. However, it is usually about 3 to 40% by weight.

If the acid value of the graft copolymer is less than 30 mgK OH/g resin, the graft copolymer cannot be made water-soluble even if neutralized with a base, whereas if it exceeds 260 mgK OH/g resin, it becomes water resistant. .

Other radically polymerizable components are appropriately selected depending on the use of the silicone-based graft copolymer, and the amount used is 1
It is preferably 0 to 96% by weight, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylate.
Isobutyl acrylate, tert-(meth)acrylate
Butyl, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, (meth)
2-ethylhexyl acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, cyclohexyl (meth)acrylate,
Benzyl (meth)acrylate, phenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, polyalkylene glycol (meth)acrylate, (meth)acrylic acid ester, (meth)acrylate dimethylaminoethyl, (
(meth)acrylic acid esters such as perfluoroalkyl meth)acrylate, aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, (meth)acrylonitrile, vinyl acetate, vinyl propionate, N-methylol (meth) Examples include acrylamide, vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride, trichlorethylene, and the like.

For radical copolymerization to obtain a graft polymer, known methods such as radiation irradiation and a method using a radical polymerization initiator can be used, but the method using a radical polymerization initiator is easier to perform the polymerization operation and produces less It is preferable from the viewpoint of ease of controlling the molecular weight of the graft polymer, and it is more preferable to use a solution polymerization method using an organic solvent.

Solvents used in the solution polymerization method include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, acetate ester solvents such as ethyl acetate and butyl acetate, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, cyclohexane, and hexane. , aliphatic hydrocarbon solvents such as heptane, methanol, ethanol, isopropanol, methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, alcohol solvents such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, tetrahydrofuran, dioxane, dimethyl Solvents such as formamide, dimethyl sulfoxide, hexamethylphosphoamide, etc. When making an aqueous solution, if the organic solvent used is not miscible with water, a step to remove the organic solvent is required, so alcohol-based solvents that can mix freely with water Solvents, acetone, dioxane, etc. are preferred.

As the radical polymerization initiator, any of those commonly used in radical polymerization can be used, and an appropriate one can be selected depending on the polymerization method.For example, as an inorganic radical polymerization initiator, ammonium persulfate, Hydrogen peroxide is used as an organic polymerization initiator, and 2,2-his(
Peroxyketals such as tert-butylperoxy)octane, hydroperoxides such as cumene hydroperoxide, dialkyl peroxides such as tert-butylcumyl peroxide, diacyl peroxides such as benzoyl peroxide, peroxydicarbonates,
Examples include azo compounds represented by peroxy ester and 2,2'-azobisisobutyronitrile.

It is possible to use a relatively low polymerization temperature, suppress side reactions, and obtain a highly purified graft polymer with a clear structure.
Organic peroxides and azo compounds with low decomposition temperatures are preferred, and azo compounds are particularly preferred. Specific examples of Ab-based compounds include 2,2°-azobisisobutyronitrile, 2
, 2'-azobis(2-methylbutyronitrile),
Azobis-4-cyanovaleric acid, Azobis(2,4-
dimethylvaleronitrile), azobis(4-methoxy-
2,4-dimethylvaleronitrile), dimethyl-2,2
' -azobisisobutyrate and azobis-1-
Examples include cyclohexacarbonitrile.

Further, in order to adjust the molecular weight and viscosity, a serial transfer agent can be used as necessary, such as mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 1-butanethiol, 2-methyl-2-propanethiol, 2-
Mercaptoethanol, ethyl mercaptoacetate,
Thiophenol, 2-naphthalenethiol, dodecylmercaptan, thioglycerol, etc. can be used.

The temperature of radical copolymerization is generally 50 to 150°.
The temperature is preferably about C, more preferably 60 to 100°C. In addition, the polymerization time is suitable for 3 to 100 hours,
Preferably it is 5 to 10 hours.

A base is added to the thus obtained graft copolymer solution to neutralize some or all of the carboxyl groups to obtain an aqueous graft copolymer.

Examples of the base used include inorganic alkali metal bases such as caustic soda and caustic potash, ammonia or triethylamine, diisopropylamine, monoethanolamine,
These are primary, secondary, or tertiary amine compounds such as triethanolamine, diisopropanolamine, and dimethylethanolamine, or heterosubstituted amine compounds such as pyridine and piperidine.

The amount of neutralization of carboxyl groups is 0.0% per mole. An amount of base of 5 molar equivalents or more is required. If the amount is less than 0.5 molar equivalent, the graft copolymer will precipitate in water, making it impossible to make it aqueous.

Surprisingly, the graft copolymer synthesized in this manner did not show any insolubilization of the silicone portion due to its aqueous nature. The exact reason why a water-soluble graft copolymer can be obtained despite the presence of a highly hydrophobic silicone moiety to some extent is unclear. Presumably, in an aqueous solution, the hydrophobic silicone part is oriented within the extremely small micelle, and the hydrophilic carboxylate part is oriented outside the micelle, making it appear to be dissolved in water. It can be done.

The aqueous silicone coating agent of the second invention in the present invention comprises the silicone macromonomer, α, β-ethylenically unsaturated carboxylic acid, alkyl (meth)acrylate or hydroxyalkyl (meth)acrylate, and optionally It consists of an aqueous silicone-based graft copolymer obtained by copolymerizing other radically polymerizable monomers, and can be made into a coating agent by the following method.

In the case of the obtained aqueous solution of the graft copolymer of the present invention, the obtained aqueous solution is applied as it is or further diluted with water and applied to the object to be coated. It will be done. In this case, the copolymer is
It is possible to crosslink and cure by a conventionally known method, and specifically, (a) when the copolymer has a hydroxyl group, it is possible to cure the copolymer by a method derived from the hydroxyl group and α,β-ethylenically unsaturated carboxylic acid. A crosslinking reaction that occurs when carboxyl groups or esterification reactions occur.

(b) Water-soluble or water-dispersible amino resins (fully alkyl type methylated melamine, methylol group type methylated melamine, imino group type methylated melamine, imino group type etherified melamine, glycol urea resin, carboxy-modified amino resin, etc. ).

(C) Chelation reaction between a carboxyl group and a transition metal salt by adding zinc chloride or the like used as an ionomer resin.

(d) Self-crosslinking reaction when N-methylol groups such as N-methylol acrylamide are introduced into a copolymer component.

There are several examples.

In addition, the coating agent of the present invention may contain other resins other than the silicone copolymer of the present invention, such as acrylic resins, epoxy resins, etc., within the range that does not impair the properties as a silicone coating agent provided by the silicone copolymer of the present invention. A curable composition consisting of a resin, an unsaturated polyester resin, a fluorine resin, and a radically polymerizable component as a polymer precursor such as polyester polyacrylate disclosed in JP-A-49-120889 is blended. may be done. The amount of resin other than the graft copolymer used is desirably 50% by weight or less based on the total amount of the graft polymer and these resins.

Furthermore, additives such as fillers, various stabilizers, and pigments may be added to the coating agent of the present invention, and specifically, various silicas, calcium carbonate, magnesium carbonate, titanium oxide, iron oxide, glass, etc. Additives include fibers, dispersion stabilizers, antioxidants, antistatic agents, ultraviolet absorbers, film-forming aids, antifoaming agents, and leveling agents.

The coating amount of the coating agent of the present invention on the object to be coated is suitably 0.01 to 100 g/m2, more preferably 0.05 to 50 g/m2.

The coating can be applied by any coating method such as spray, brush coating, roll coater, bar coater, etc.

[Subjects to be coated] The objects to be coated with the silicone coating agent of the present invention include rubbers, plastic parts, plastic films, metals, metal plates, etc. that require weather resistance, heat resistance, lubricity, mold releasability, etc. Ceramics, glass, wood, paper, etc., and specific applications of the silicone coating agent of the present invention include anti-graffiti paint, anti-sticking paint, antifouling paint, electrodeposition paint, and prevention of freezing and dew condensation. Vehicles for paints and highly weather-resistant paints; foaming agents for urethane foam, highly weather-resistant coating agents for resin-impregnated wood, polishing agents for paper and leather, water repellent and waterproof materials for Japanese straw, bricks, wood, concrete, etc. Stain treatment agent, release paper, masking tape, adhesive tape, confectionery cup, mold release agent for concrete, mortar, and plaster molds and stamping foil, mold release agent for plastic and ceramic molds, magnetic tape, etc. There are lubricating coating agents for films, cassette sheets, thermal transfer recording films, etc., lubricating protective coating agents for magnetic cards, IC cards, cash cards, credit cards, brivate cards, magnetic tickets, etc., and they can be used for these purposes. Can be used as a base material or coated object.

[Examples, Reference Examples, and Comparative Examples] The present invention will be explained in more detail by giving Examples, Reference Examples, and Comparative Examples below.

The physical properties of the silicone copolymer on each side and the physical properties of the coating film of the silicone coating agent obtained from the copolymer were evaluated in the following manner.

In addition, parts and % represent parts by weight and % by weight, respectively.

・Water resistance: Impregnate gauze with water, wrap it around your index finger, and rub the painted surface. Observe the condition of the paint film after rubbing it back and forth 100 times.

・Solvent resistance: Thoroughly impregnate gauze with methyl ethyl ketone, wrap it around your index finger, and rub the painted surface.

Observe the condition of the paint film after rubbing it back and forth 100 times.

・Weather resistance: QUV accelerated weather resistance test (UV/condensation cycle accelerated weather resistance test) ATLAS-U newly manufactured by Toyo Seiki
60°C x UV irradiation x 4 hours using VCON, -40
The gloss value was measured after 2,000 hours under the repeated conditions of °C x saturated humidity x 4 hours. In addition, it was expressed as a retention rate (%) when the glossiness before the accelerated weathering test was set as 100.

・Flexing resistance: According to JIS K5400 bending resistance,
Tests were conducted with various diameters of the mandrel of the bending resistance tester, and the diameter of the mandrel was the smallest diameter when only cracks or flakes were observed in the coating film.

- Lubricity: Using a surface property measuring device manufactured by Shinrai Kagaku Co., Ltd., a coated object coated with the coating agent of the present invention was used as a sample, and the lubricity was measured under the following conditions and expressed as a coefficient of kinetic friction (μk).

Contact: Stainless steel ball with a diameter tomm.

Load: 50g0 Traveling speed: 150mm/min.

Temperature: 25°C6 Humidity: 60%RH.

・Releasability 2 Using a coated object coated with the coating agent of the present invention as a sample, KOKUYO sellotape (24 mm width) was pressed onto the coating surface, and the sellotape was tensile tested at a tensile tester at a speed of 200 mm/min, 25 °C260%
Tensile strength (g) when peeled at 180° under RH conditions
It was expressed as・Adhesion: 1m with a cutter knife to the coating film
After drawing 100 dots at m intervals, a cellophane tape peeling test was conducted and the number of remaining coatings was expressed.

Example 1 α, in a flask equipped with a stirrer, condenser, and thermometer.
ω-dihydroxypolydimethylsilicone H3 ■ [HO-(S i -0) n-H n is 300 on average]
111 g (0,005 mol) of H3, 0.12 g of p-toluenesulfonic acid, 74 g of toluene and 37 g of methyl ethyl ketone (hereinafter abbreviated as MEK), 2.48 g of γ-methacryloyloxypropyltrimethoxysilane (
0.01 mol) and heated at 70°C for 3 hours.

Thereafter, after cooling, 30 g of a basic anion exchange resin (A-21 manufactured by Organo) was added to the reaction solution, and the mixture was stirred at 40° C. for 2 hours to neutralize it. The ion exchange resin was removed by filtration, and the filtrate was distilled under reduced pressure to remove the solvent, yielding 110 g of a colorless and transparent oily macromonomer. The number average molecular weight (number average molecular weight in terms of polystyrene determined by gel permeation chromatography) of the obtained silicone macromonomer was 35.000. Next, per 30 parts of this macromonomer, 20 parts of methyl methacrylate, 20 parts of butyl methacrylate, 2 parts of methacrylic acid,
-20 parts of hydroxyethyl, 10 parts of methacrylic acid, n
-Dodecyl mercaptan 1.0 part, 2,2' -Azobisisobutyronitrile 1.0 part, isopropanol 10
Pour 0 parts into a flask equipped with a stirrer, condenser, thermometer, and nitrogen inlet tube, and then bubble with nitrogen.
After heating at 0°C for 4 hours, add 5 parts of AIB No.
The mixture was heated at the same temperature for 4 hours to synthesize a graft copolymer with an acid value of 65 mgKOH/g resin.

To the obtained reaction solution, 100 g of a 5% aqueous solution of dimethylethanolamine was gradually added while stirring. The resulting liquid was a clear solution with a pH of 7.7.

Next, the obtained aqueous solution was diluted to 30% with water, and then applied to a glass plate using a bar coater to a film thickness of about 20μ, dried at 60°C for 30 minutes, and then cured at 150°C for 30 minutes. Ta.

The water resistance, solvent resistance, weather resistance, bending resistance, lubricity, mold releasability, and adhesion of the resulting coating film were measured using the methods described above. No change was observed, and the gloss retention rate was 85% in the weather resistance test.
Bending resistance 2mm, lubricity 0.031μk, mold release property 50g
/1 nch, adhesion was 100/100.

Example 2 In Example 1, silicone macromonomer was synthesized using an anionic polymerization method (FMO7 manufactured by Chisso).
25, molecular weight 10,000), the obtained acid value was 65 mgK.
A solution of the graft copolymer of OH/g resin was diluted with 1.0 g of triethylamine. An aqueous solution of the graft copolymer was obtained by the same operations as in Example 1, except that 100 g of a 7% aqueous solution was used to form an aqueous solution, and then the same method was used using the obtained aqueous solution of the graft copolymer. Various physical properties were measured for the coating film prepared.

As a result, no change was observed in the coating film in water resistance and solvent resistance tests, and in weather resistance tests, gloss retention was 80%, and bending resistance was 2 m.
m, lubricity is 0.038μk, mold release property is 40g/1nch
, the adhesion was 100/100.

Example 3 Using 100 parts of isopropanol as a polymerization solvent, 30 parts of the soricone macromonomer synthesized in Example 1 as monomer components, 25 parts of methyl methacrylate, 20 parts of butyl acrylate, 5 parts of styrene, and 20 parts of methacrylic acid. The resulting solution of the graft copolymer with an acid value of 163 mgK OH/g resin was diluted with a 5% aqueous solution of ammonia.
A graft copolymer aqueous solution was obtained in the same manner as in Example 1, except that the isopropanol was removed by distillation under reduced pressure, and then the obtained graft copolymer aqueous solution was used. A coating film was prepared in the same manner as in Example 1, and the water resistance, solvent resistance, weather resistance,
When we measured bending resistance, lubricity, mold releasability, and adhesion, we found that the water resistance and solvent resistance tests showed slight swelling in the paint film, and the weather resistance tests showed gloss retention of 80% and bending resistance. sex 2m
m, lubricity is 0.025μk, mold release property is 22g/1nch
The adhesion was 100/100.

Example 4 100 parts of the reaction solution obtained in Example 1 was added with water to make the solid content 20%.
After diluting to
When we measured water resistance, solvent resistance, weather resistance, bending resistance, lubricity, mold releasability, and adhesion, no change was observed in the coating film in the water resistance/solvent resistance test, and the weather resistance test The gloss retention rate was 85%, the bending resistance was 2 mm, the lubricity was 0.047 μk, the mold release property was 66 g/1 nch, and the adhesion was 100/100.

(c) Effects of the Invention The aqueous graft copolymer produced by the present invention exhibits the properties of silicone on the surface and simultaneously exhibits the functions of a portion of the backbone polymer. Therefore, the coating film made of it has water resistance, It has good solvent resistance, weather resistance, lubricity, mold releasability, and adhesion, and it can be used in the form of an aqueous solution without the risk of fire due to organic solvents and is nontoxic, so it is pollution-free and resource-saving. Useful.

The aqueous graft copolymer according to the present invention is suitably used as a coating agent for the various coated objects described above.

Patent applicant Takuya Gosei Kagaku Kogyo Co., Ltd. December 1991
17th of the month

Claims (1)

[Claims] 1. The following radical copolymerization components (A), (B) and (C)
obtained by copolymerizing, acid value 30-260mgKOH/
A method for producing an aqueous silicone-based graft copolymer, which comprises reacting a resin graft copolymer with a base. (A) Macromonomer having a (meth)acryloyl group at one end of silicone (B) α,β-ethylenically unsaturated carboxylic acid (C) Radically polymerizable monomer 2 other than the above (A) and (B) , wherein the radical polymerization component (C) is a monomer mixture containing an alkyl (meth)acrylate or a hydroxyalkyl (meth)acrylate as a main component. A water-based coating agent consisting of a copolymer.