JPH0448511B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a coating method for forming a coating on organic coatings, wood or inorganic materials. [Prior art and problems to be solved by the invention] The present inventors have discovered a polymer whose main chain consists essentially of carbon-carbon bonds and which contains a silyl group having a hydrolyzable group at the terminal or side chain. The combination of these resins results in high gloss, weather resistance, color fastness, etc., which are characteristics of ordinary vinyl resins whose main chain is essentially composed of only carbon-carbon bonds, and excellent properties as paints, coating materials, sealants, and adhesives. In addition to its unique characteristics, the hydrolyzable silyl group improves adhesion to inorganic substrates, and it also forms a dense network structure through room-temperature crosslinking due to moisture, especially moisture in the atmosphere, resulting in solvent resistance, water resistance, and heat resistance. discovered that it could be made into a resin with high hardness and excellent weather resistance, and filed a patent application (Japanese Patent Laid-Open No. 54-36395). The present inventors further investigated silyl group-containing vinyl resins, and found that a resin composition consisting of a silyl group-containing vinyl resin and an isocyanate compound was easily cured not only at high temperatures but also at low temperatures. By further improving the excellent physical properties of vinyl resins, it becomes a coating with improved adhesion and flexibility, especially on organic coatings, wood, or inorganic materials. The inventors have discovered a method for forming a coating film having various physical properties, and have arrived at the present invention. [Means and effects for solving the problems] That is, the coating method of the present invention coats an organic coating film, wood or inorganic material with a main chain consisting essentially of repeating carbon-carbon bonds and hydration at the terminal or side chain. At least one silicon atom bonded to a decomposable group per molecule
A paint consisting of a silyl group-containing vinyl resin (A) and an isocyanate compound (B) is applied. The polymer (A) constituting the paint used in the coating method of the present invention consists of a vinyl polymer whose main chain consists essentially of carbon-carbon single bonds, and which is bonded to a hydrolyzable group at the terminal or side chain. It contains at least one, preferably two or more, silicon atoms in one molecule, and most of the silyl groups are It is indicated by. (However, X is a hydrolyzable group, R ¹ and R ² are hydrogen or an alkyl group having 1 to 10 carbon atoms, an aryl group, or an aralkyl group, and n is an integer of 1, 2, or 3). Hydrolyzable groups include halogen, alkoxy, acyloxy, ketoximate, amide, acid amide, aminooxy, mercapto, and alkenyloxy groups. The silyl group-containing vinyl resin can be produced by various methods, but the following method is hydrosilylation using a vinyl resin having a carbon-carbon double bond in the side chain or terminal and a hydrosilane having a hydrolyzable group. A method based on reaction and copolymerization of a vinyl compound and a silyl compound having a polymerizable double bond and a hydrolyzable group is an industrially effective method. This will be explained in detail below. Method by hydrosilylation A silyl group-containing vinyl resin is easily produced by reacting a hydrosilane compound with a vinyl resin having a carbon-carbon double bond under a group transition metal catalyst. The hydrosilane compound has the following general formula. (In the formula, R ¹ is hydrogen or a monovalent hydrocarbon group selected from alkyl groups having 1 to 10 carbon atoms, aryl groups, and aralkyl groups, X is a hydrolyzable group, and n is 1
to 3) Specific examples of hydrosilane compounds included in this general formula include halogenated silanes such as methyldichlorosilane, trichlorosilane, and phenyldichlorosilane; methyldiethoxysilane, methyldimethoxy Alkoxysilanes such as silane, phenyldimethoxysilane, trimethoxysilane, and triethoxysilane; Acyloxysilanes such as methyldiacetoxysilane, phenyldiacetoxysilane, and triacetoxysilane; Methyldiaminoxysilane, triaminoxysilane , methyldiaminosilane, triaminosilane, pis(dimethylketoximate)methylsilane, pis(cyclohexylketoximate)methylsilane, methyldiisopropenooxysilane, and triisopropenooxysilane. The amount of the hydrosilane compound to be used can be any arbitrary amount, but it is preferably used in an amount of 0.5 to 2 times the mole of carbon-carbon double bonds contained in the vinyl resin. Although this does not preclude the use of a larger amount of silane, it will simply be recovered as unreacted hydrosilane. Furthermore, halogenated silanes, which are inexpensive basic raw materials and have high reactivity, can be easily used as hydrosilane compounds. Silyl group-containing vinyl resins obtained using halogenated silanes harden quickly at room temperature while generating hydrogen chloride when exposed to the air, but hydrogen chloride produces a pungent odor, and when exposed to air, It is desirable to further convert the halogen functional group into another hydrolyzable functional group because it can be practically used only in limited applications due to the problem of corroding the materials used. For example, JP-A-54-
It can be converted into alkoxy, acyloxy, aminooxy, amide, acid amide, ketoximate, and mercapto groups by the method shown in 91546. The vinyl resin used in the hydrosilylation method is not particularly limited, except for vinyl compounds containing hydroxyl groups, and examples include methyl acrylate, methyl methacrylate, ethyl acrylate,
Butyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate,
Acrylic acid, methacrylic acid ester such as 2-ethylhexyl methacrylate; carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, acid anhydride such as maleic anhydride, epoxy such as glycidyl acrylate, glycidyl methacrylate, etc. compounds, amino compounds such as diethylaminoethyl acrylate, diethylaminoethyl methacrylate, aminoethyl vinyl ether,
Amide compounds such as acrylamide, methacrylamide, itaconic acid diamide, α-ethylacrylamide, crotonamide, fumaric acid diamide, maleic acid diamide, N-ptoxymethyl acrylamide, N-ptoxymethyl methacrylamide, acrylonitrile, iminol methacrylate, A resin whose main component is a copolymer selected from styrene, α-methylstyrene, vinyl chloride, vinyl acetate, vinyl propionate, etc. is suitable.
When producing these vinyl compounds alone or as copolymers, by radical copolymerizing some allyl acrylate, allyl methacrylate, diallyl phthalate, etc., carbon/carbon doubles for hydrosilylation reaction are created in the vinyl resin. It is possible to introduce the linkage at the end of the molecule or at the side chain. The amount of monomer necessary for this purpose can be arbitrarily determined depending on the number of silyl groups in the target resin. Furthermore,
The molecular weight can be controlled by adding a chain transfer agent such as n-dodecylmercaptan or t-dodecylmercaptan. When polymerizing these vinyl compounds, a solvent may or may not be used, but if used, ethers, hydrocarbons,
The use of non-reactive solvents such as acetate esters is preferred. In the hydrosilylation reaction, a transition metal complex catalyst is required in the step of reacting the hydrosilane compound with the side chain or terminal carbon-carbon double bond of the polymer. As the transition metal complex catalyst, group transition metal complex compounds selected from platinum, rhodium, cobalt, palladium and nickel are effectively used. This hydrosilylation reaction is achieved at any temperature from 50 to 150°C, and the reaction time is about 1 to 10 hours. Method by copolymerization of vinyl compound and silyl compound This method uses the formula (In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms,
A monovalent hydrocarbon group selected from an aryl group and an aralkyl group, R ³ is an organic residue having a polymerizable double bond, X is a hydrolyzable group, and n is an integer of 1, 2, or 3) It is produced by radical copolymerization of silane compounds and various vinyl compounds. Examples of silyl compounds include: _CH2 =CHSi( _OCH3 ) ₃ , _CH2 = _CHSiCl3 , _CH2 =CHCOO( _CH2 ) _3Si ( _OCH3 ) ₃ , _{CH2 =} CHCOO( _CH2 ) _3SiCl3 , _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _OCH3 ) ₃ , _CH2 =C( _CH3 ) _COO ( _CH2 ) _3SiCl3 , etc. These silyl compounds are synthesized by various methods, but for example, acetylene, allyl acrylate, allyl methacrylate, diallyl phthalate and methyldimethoxysilane, methyldichlorosilane, trimethoxysilane, trichlorosilane are synthesized under a group transition metal catalyst. It can be produced by reaction. As the vinyl compound, it is possible to use the same kind of compound used in the synthesis of vinyl resin in the above method, but in addition to those described in the method, 2.
-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxyvinyl ether, N-
Vinyl compounds containing hydroxyl groups such as methylol acrylamide and Aronix 5700 (manufactured by Toagosei Co., Ltd.) can also be used. Synthesis of these copolymers of vinyl compounds and silyl compounds is carried out by ordinary solution polymerization methods.
A vinyl compound, a silyl compound, a radical initiator, and a chain transfer agent such as n-dodecyl mercaptan or t-dodecyl mercaptan are added as necessary to obtain a silyl group-containing copolymer with an appropriate molecular weight at 50 to 150°C. React with. A solvent may or may not be used, but when used, it is preferable to use a non-reactive solvent such as ethers, hydrocarbons, and acetic esters. The hydrolyzable groups of the silyl group-containing vinyl resin thus obtained can be converted, for example, by the method disclosed in JP-A-54-91546. In this way, a silyl group-containing vinyl resin whose main chain is substantially composed of a vinyl polymer and which has at least one silicon atom in one molecule bonded to a hydrolyzable group at the terminal or side chain is obtained. can get. The composition of each monomer constituting the silyl group-containing vinyl resin used in the production of the paint used in the present invention is not particularly limited, but may include carboxylic acid groups, hydroxyl groups, amino groups, amide groups, etc. as exemplified above. By including an ethylenically unsaturated organic monomer containing active hydrogen, it is possible to improve adhesion and at the same time react with the isocyanate compound to obtain a more excellent coating material. From the viewpoint of weather resistance as a paint (less cracking, yellowing, chalking, etc. even when exposed outdoors), it is preferable that the main chain does not contain unsaturated bonds. When synthesizing a group-containing vinyl resin, it is not preferable to use a compound containing a conjugated double bond such as butadiene as a copolymerization component. The isocyanate compound (B) is not particularly limited as long as it has at least two isocyanate groups in one molecule, and examples include paraphenylene diisocyanate, tolylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, octadecyl diisocyanate, and naphthalene. Diisocyanate, 4,4'-diphenylmethane diisocyanate, dianisidine isocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-
Diisocyanate, bifunctional diisocyanate such as methylcyclohexylene diisocyanate, isophorone diisocyanate; polyhydric alcohol such as trimethylolpropane and diisocyanate such as tolylene diisocyanate, hexamethylene diisocyanate, etc.
Addition compounds with functional diisocyanates, and copolymers of bifunctional diisocyanates such as tolylene diisocyanate and hexamethylene diisocyanate, such as "Desmodyur" manufactured by Sumitomo Bayer Ltd.
"Sumidiur"etc.; diamines such as ethylenediamine, triethylenediamine, and phenylenediamine; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, fumaric acid, and phthalic acid; Included are addition compounds of polysiloxanes and bifunctional diisocyanates; and the like. From the viewpoint of weather resistance of the resin composition of the present invention, an isocyanate compound containing no aromatic ring in the molecule is preferable. The amount of the isocyanate compound (B) is not particularly limited, but is 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, per 100 parts by weight of the silyl group-containing vinyl resin. When the paint used in the present invention is exposed to the atmosphere, it forms a network structure and hardens at room temperature. During curing, a curing accelerator may or may not be used. When used, alkyl titanates, metal salts of carboxylic acids such as tin octylate, dibutyltin dilaurate, and lead octylate, sulfide type and mercaptide type organotin compounds such as monobutyltin sulfide and dioctyltin mercaptite, phosphoric acid , p-toluenesulfonic acid, acidic catalysts such as phthalic acid, amines such as tetraethylenepentamine, triethylenediamine, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, alkalis such as potassium hydroxide, sodium hydroxide, etc. Catalysts are effective. The amount of these curing accelerators added is preferably 0.001 to 10% by weight based on the resin. The paint used in the present invention cures at room temperature or low temperature and becomes a resin with excellent weather resistance and adhesion, so it is particularly useful as an organic paint film or a paint on the surface of wood. It can also be used for tin plates, galvanized iron plates, aluminum plates, zinc plates, roof tiles, slate, etc.). In addition, since it can be cured at low temperatures, it is effective as a repair paint for bridges and automobiles. Ethyl silicate, silane coupling agent, etc.
By adding a compound capable of co-condensation with the silyl group-containing vinyl resin of the present invention, it is also possible to improve physical properties such as surface hardness and sealing performance. It can also be blended with various resins currently used as paints and coatings, such as lacquer paints, acrylic lacquer paints,
It can be used by mixing with thermosetting acrylic paints, alkyd paints, melamine paints, epoxy paints, etc. in appropriate proportions, and can improve the physical properties such as weather resistance and adhesion of these paints and coatings. . The paint used in the present invention contains various fillers,
It is possible to mix pigments and the like. Fillers and pigments include various silyls, calcium carbonate, magnesium carbonate, glass fibers, various organic pigments,
Various inorganic pigments can be used. Next, the present invention will be specifically explained using examples. Production Example 1 In 90 g of xylene solvent heated to 90°C, 30 g of styrene, 16 g of allyl methacrylate, 20 g of methyl methacrylate, 19 g of n-butyl methacrylate, 14 g of butyl acrylate, 4 g of maleic anhydride, n-
A solution of 2 g of azobisisobutyronitrile dissolved in 2 g of dodecyl mercaptan was added dropwise and reacted for 10 hours to obtain a vinyl polymer containing allylic unsaturated groups with a molecular weight of 8,000. In the infrared absorption spectrum of this product, absorption due to carbon-carbon double bond at 1648 cm ^-1 and absorption of acid anhydride at 1780 cm ^-1 were observed.
40 g of solvent is removed from the resulting polymer solution under reduced pressure. A solution of 1.5 g of methyldimethoxysilane and 0.0005 g of chloroplatinic acid dissolved in isopropanol was added to 16 g of the obtained vinyl copolymer solution containing an allylic unsaturated group, and the mixture was reacted at 90° C. for 6 hours under sealed conditions. In the infrared absorption spectrum of this product, the absorption at 1648 cm ^-1 disappeared, and a silyl group-containing vinyl polymer was obtained. Production example 2 Styrene was added to 70g of xylene heated to 90℃.
30g, γ-methacryloxypropyltrimethoxysilane 22g, methyl methacrylate 22g, n-butyl methacrylate 15g, butyl acrylate 18g, n
A solution of 2 g of azobisisobutyronitrile dissolved in 1 g of -dodecyl mercaptan was added dropwise and reacted for 10 hours to obtain a silyl group-containing vinyl resin with a molecular weight of 12,000. Production example 3 Styrene was added to 70g of xylene heated to 90℃.
30g, 22g of γ-methacryloxypropyltrimethoxysilane, 22g of methyl methacrylate, 15g of n-butyl methacrylate, 18g of butyl acrylate, 4g of acrylamide, 10g of acetone, 2g of azobisisobutyronitrile dissolved in 2g of n-dodecylmercaptan. The solution was added dropwise and reacted for 10 hours.
A silyl group-containing vinyl resin with a molecular weight of 12,000 was obtained. Production example 4 Styrene was added to 70g of xylene heated to 90℃.
30g, γ-methacryloxypropyltrimethoxysilane 22g, methyl methacrylate 22g, n-butyl methacrylate 18g, methyl acrylate 18g, 2-
A solution of 2 g of azobisisobutyronitrile dissolved in 6 g of hydroxyethyl methacrylate and 4 g of n-dodecyl mercaptan was added dropwise and reacted for 10 hours to obtain a silyl group-containing vinyl resin with a molecular weight of 6,000. Examples 1 to 4 and Comparative Examples 1 to 4 To the resin solutions obtained in Production Examples 1 to 4 above, the isocyanate compounds and curing accelerator shown in Table 1 were added to adjust the coating viscosity (15 seconds with food cup No. 4). diluted with xylene and applied to the organic coating shown in Table 1,
The same heat treatment shown in Table 1 was carried out, and 3 days later, adhesion (burlap test) and scratch thinner resistance (spot test) were conducted. As comparative examples, cases in which no isocyanate compound was included are similarly shown in Table 1 as Comparative Examples 1 to 4, respectively.

[Table] As shown above, it can be seen that the adhesion on organic coatings (goblin test, scratch thinner resistance) has been significantly improved. *1 Kansai Paint Co., Ltd., melamine resin baking paint *2 *5, *8 Sankyoki Co., Ltd., stabilizer for PVC *3 Isamu Paint Co., Ltd., 2-component urethane surfer *4 *7 Manufactured by Bayer Co., Ltd., isocyanate compound *6 Manufactured by Kansai Paint Co., Ltd., nitrocellulose modified acrylic lacquer *9 Manufactured by Isamu Paint Co., Ltd., lacquer surfer [Effects of the invention] According to the coating method of the present invention, A coating film with excellent physical properties such as adhesion and weather resistance can be formed on organic coatings, wood, or inorganic materials.

Claims (1)

[Scope of Claims] 1. On an organic coating film, wood or inorganic material, a silicon atom whose main chain consists essentially of repeating carbon-carbon bonds and which is bonded to a hydrolyzable group at the terminal or side chain in one molecule. A coating method comprising applying a paint comprising a silyl group-containing polymer (A) having at least one silyl group and an isocyanate compound (B). 2. The coating method according to claim 1, wherein the silyl group-containing polymer (A) is a vinyl type polymer whose main chain consists of only repeating carbon-carbon single bonds. 3. The coating method according to claim 1 or 2, characterized in that the polymer (A) is comprised of 100 parts by weight and the isocyanate compound (B) is comprised of 0.1 to 100 parts by weight.