JPS648033B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a silyl compound obtained by radical polymerization of a vinyl compound and an unsaturated organic silane having a hydrolyzable group in the presence of a chain transfer agent, and which is made into a low polymer (number average molecular weight of 10,000 or less) with a chain transfer agent. The present invention relates to a paint made of a group-containing vinyl polymer. The silyl group-containing vinyl polymer of the present invention is a compound containing a silyl group that has a hydrolyzable group at its terminal or side chain, and is therefore a characteristic of vinyl polymers. In addition to weather resistance and high gloss, adhesion is improved, and in the absence of a catalyst or in the presence of a curing catalyst, moisture, especially atmospheric moisture, forms a dense network structure through room-temperature crosslinking, resulting in solvent resistance, water resistance, The resin has excellent heat resistance, hardness, and weather resistance. Since it crosslinks at room temperature or low temperature and becomes a resin with excellent physical properties, it is very suitable as a resin for paints and coatings, where pollution-free and resource-saving are currently attracting great attention. Furthermore, since the polymer used in the present invention is a compound containing a silyl group having a hydrolyzable group at the terminal or side chain, it can be used in the same manner as a normal silane coupling agent. ,
It can be used in combination with ordinary resins and adhesives to improve the adhesion between the resin material and the inorganic compound substrate or filler. Moreover, the silyl group-containing vinyl polymer of the present invention is
By including various polar vinyl compounds as copolymerization components, the adhesion characteristics to inorganic compounds due to the silyl group having a hydrolyzable group are further increased, and at the same time, the adhesion to organic compounds is greatly increased. Therefore, it is very convenient as a paint and coating resin that can be used not only for inorganic materials but also for organic materials. In particular, a major feature of the silyl group-containing vinyl polymer of the present invention is that by controlling the amount of the chain transfer agent, it can be made into a low polymer (number average molecular weight of about
10,000 or less), and by controlling the amount of unsaturated organic silane, it is possible to obtain sufficient physical properties of the coating film obtained by curing. One of the major advantages of low polymerization is that it can be applied as a high solid content type paint or coating agent, which contributes to resource saving and pollution-free, while also reducing the need for one thick coating. It is possible to achieve low cost, and it is also possible to improve the physical properties of the coating film, such as gloss. One of the other characteristics concerns storage stability. Various compounds containing a silyl group bonded to a hydrolyzable group as shown in the present invention are known, and include paints, coating agents,
It is suitable for use as adhesives, sealants, silane coupling agents, etc., but during storage, it tends to react with the system and gradually increase its viscosity. Although it is stored and used in a state that is kept as low as possible, it is unavoidable that moisture in the air will be mixed in when used repeatedly, and when pigments and fillers are added, water on the surface of the compound will be mixed in. , holding stability is a big issue. The present inventors have also filed a patent application regarding the addition of alcohol and the addition of a hydrolyzable ester compound in order to improve storage stability (Japanese Patent Application No. 1983).
-25728, 54-121181) Although not perfect, as a result of further intensive study, we discovered that it is possible to dramatically improve the polymer by using a chain transfer agent to reduce the polymer, which led to the present invention. . The effectiveness will be shown in the examples, but surprisingly, a silyl group-containing vinyl polymer containing polar vinyl monomers such as acrylamide and maleic anhydride as a copolymerization component has been developed, which was completely impossible with conventional techniques. In the case of coalescence, within the scope of the present invention, sufficient physical properties of the cured coating film and satisfactory storage stability were obtained even in the state of pigment dispersion. In addition to the method of using a chain transfer agent shown in the present invention, the method of reducing the molecular weight carried out in the present invention includes a method of using a large amount of a radical initiator. It is difficult to remove, there is a possibility of gelation, and it is difficult to reproducibly control the molecular weight, and the molecular weight distribution is wide.It is only by using a chain transfer agent that a low degree of polymerization can be achieved reproducibly, and the molecular weight distribution is narrow. A silyl group-containing vinyl polymer is obtained which has a low solution viscosity and is suitable for high solid content (high solid content concentration). It is unclear why the silyl group-containing vinyl polymer of the present invention has excellent retention stability, but the narrow molecular weight distribution resulting from the use of a chain transfer agent as well as low molecular weight is a major factor. This is thought to be the cause. In this way, it could not have been predicted that a region of low molecular weight that can be used for high solids paints and coatings and that has sufficient cured film physical properties and storage stability exists in the low molecular weight region that can be obtained using chain transfer agents. Yes, it is therefore a completely new substance. That is, the present invention provides (A) 95 to 62 mol% of a vinyl compound, (B) 4 to 30 mol% of a formula (R is an organic residue having a polymerizable double bond,
R' is an alkyl group having 1 to 10 carbon atoms, an aryl group,
A monovalent hydrocarbon group selected from aralkyl groups, X
is a hydrolyzable group, and n is an integer of 0 to 2. ) unsaturated organic silane (C) 1 to 8 mol% chain transfer agent containing a hydrolyzable silyl group-containing mercaptan compound as an essential component. The present invention relates to a high-solids paint with excellent storage stability made of a silyl group-containing polymer obtained by copolymerization. The vinyl compound used in the present invention is not particularly limited, and includes methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,
Acrylic acid, methacrylic acid esters such as butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, 2-methylstyrene, alkyl vinyl ether, vinyl chloride, vinyl acetate, vinyl propionate, Vinyl compounds with polar groups include acrylic acid, methacrylic acid, itaconic acid,
Acids such as maleic acid and acid anhydrides such as maleic anhydride, acrylamide, methacrylamide, N
- Amide groups such as methylol acrylamide and N-methylol methacrylamide, epoxy groups such as glycidyl acrylate and glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2- Examples include vinyl compounds containing a hydroxyl group such as hydroxy vinyl ether, an amino group such as diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and aminoethyl vinyl ether, and others such as acrylonitrile and iminol methacrylate. By including vinyl compounds containing such polar groups in the copolymerization component, it is possible to greatly improve physical properties such as adhesion, but since it has a negative effect on storage stability, the content of vinyl compounds containing polar groups is is preferably 0 to 20 mol%, preferably 0 to 10 mol%. When the silyl group-containing vinyl polymer of the present invention is used as a paint, a high-gloss paint film can be obtained by containing 20 mol% or more of styrene in terms of the gloss of the paint film obtained after curing. The unsaturated organic silane used in the present invention includes _CH2 =CHSi( _OCH3 ) ₃ ,

[Formula] CH ₂ = CHSi (OC ₂ H ₅ ) ₃ ,

[Formula] CH ₂ = CHCOO(CH ₂ ) ₃ Si(OCH ₃ ) ₃ ,

【formula】

【formula】

【formula】

etc. The amount of unsaturated organic silane is determined based on the balance between the molecular weight (controlled by a chain transfer agent) and the physical properties of the coating film, and in the low molecular weight region, sufficient physical properties of the coating film can be obtained by increasing the amount of unsaturated organic silane. Therefore, in the scope of the present invention, it is 4 to 30 mol%, preferably 5 to 20 mol%. A compound containing a hydrolyzable silyl group-containing mercaptan compound as an essential component is used, and various compounds can be considered, but for example, γ-mercaptopropyltrimethoxysilane can be preferably used. The amount of the chain transfer agent is preferably 1 to 8 mol %, and by using the chain transfer agent within this range, a polymer having a number average molecular weight of 10,000 or less and a molecular weight distribution of 2 or less can be obtained. As the radical initiator used in the present invention,
Azobisisobutyronitrile, Azobis2,4-
Azobis compounds such as dimethylvaleronitrile, and peroxides such as benzoyl peroxide and lauroyl peroxide are used. The silyl group-containing vinyl polymer used in the present invention is synthesized by a conventional solution polymerization method, in which a vinyl compound, an unsaturated organic silane, a chain transfer agent, and a radical initiator are reacted at 50 to 150°C. It will be done.
A solvent may or may not be used, but when used, it is preferable to use a non-reactive solvent such as ethers, aromatic and aliphatic compounds, hydrocarbons, and acetic acid esters. When the silyl group-containing vinyl polymer used in the present invention obtained in this manner is exposed to the atmosphere, it forms a network structure and hardens at room temperature. When curing the silyl group-containing vinyl polymer used in the present invention, a curing accelerator may or may not be used, but when using a curing accelerator, alkyl titanates, octylic acid Tin and metal salts of carboxylic acids such as dibutyltin dilaurate and dioctyltin dimaleate, dibutylamine-2
- Amine salts such as hexoate, amines such as tetraethylenepentamine, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, acids such as γ-toluenesulfonic acid and phthalic acid, and alkaline catalysts such as potassium hydroxide. It is valid. The amount of these curing accelerators added is 0.001 to 10% by weight based on the polymer.
It is preferable to use it in The silyl group-containing vinyl polymer used in the present invention is effective as a paint or coating agent because it can be cured at room temperature or at low temperature. In particular, the silyl group-containing vinyl polymer used in the present invention has greatly improved storage stability and can also be used as a one-component paint or coating agent containing a curing catalyst other than an alkali. Furthermore, it can be blended with various resins currently used as paint coating agents, and physical properties such as adhesion and weather resistance can be improved. The silyl group-containing vinyl polymer used in the present invention has excellent storage stability even when mixed with various fillers, pigments, etc., and can be used with various silicas, calcium carbonate, magnesium carbonate, glass fiber, titanium oxide, titanium oxide, etc. Iron, and especially transparent iron oxides with high water content, can also be used. In this way, it is useful not only for the above-mentioned uses but also as a coating composition for aircraft structures, automobiles, glass, etc., a sealing composition, and a surface treatment agent for various inorganic materials. Examples will now be described. Examples and Comparative Examples The vinyl compound, unsaturated organic silane, chain transfer agent, and radical initiator (azobisisobutyronitrile) shown in the table below were dropped into 100 g of xylene heated to 90°C and reacted for 10 hours. A silyl group-containing vinyl polymer having the molecular weight shown in the table below was obtained. A-189: HSCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ Manufactured by Nippon Unica Co., Ltd.

[Table] The obtained silyl group-containing vinyl polymer was mixed with titanium oxide at a ratio of 1:1 to the solid content, and dispersed in a ball mill to make white enamel. To the resulting white enamel, 10 parts of methanol and 7 parts to the polymer were added.
of ethyl silicate was added, diluted with xylene to an appropriate solution viscosity, sealed, and the storage stability at 50°C was examined. Similarly, 3 parts of dioctyltin dimerate was added to the white enamel containing 10 parts of methanol and 7 parts of ethyl silicate, and while checking the pot life, it was applied on a lacquer type surfer and heated at 60°C for 40 minutes. The pencil hardness, solvent resistance (spot test), and gloss (60 degree specular reflection) were examined on the third day.

[Table] As shown above, it is clear that the polymer has excellent storage stability and physical properties. Furthermore, the gloss has been improved by lowering the molecular weight. Transparent iron oxide (Trans Oxide Red, manufactured by Hilton Davis) was mixed with the solid content of the polymers obtained in Examples and Comparative Example 3 at a ratio of 100:30.
The polymer was dispersed in a Pall mill to make an enamel, and 10 parts of methanol and 7 parts of ethyl silicate were added to the polymer to check its storage stability at 50°C. The enamel of Comparative Example 3 gelled in one day. However, the enamel of the example slightly thickened after 3 weeks but remained stable.

Claims (1)

[Claims] 1 (A) 95-62 mol% vinyl compound (B) 4-30 mol% formula; (In the formula, R is an organic residue having a polymerizable double bond, R' is a monovalent hydrocarbon group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group, and an aralkyl group, and X is a hydrolyzable group. , n is an integer of 0 to 2.) Unsaturated silane (C) 1 to 8 mol% chain transfer agent containing a hydrolyzable silyl group-containing mercaptan compound as an essential component (A), ( A paint consisting of a silyl group-containing vinyl polymer obtained by copolymerizing B) and (C) using a radical initiator. 2. The paint according to claim 1, wherein the hydrolyzable silyl group-containing mercaptan compound is γ-mercaptopropyltrimethoxysilane.