JP2819412B2 - Resin composition for coating - Google Patents

Description

The present invention relates to a novel and useful coating resin composition. More specifically, the present invention relates to a vinyl monomer (A) having a polymerizable unsaturated double bond and a siloxy group in a molecule and a vinyl monomer having a polymerizable unsaturated double bond and an isocyanate group in a molecule, respectively. Monomer (B)
And, if necessary, the monomer (A),
(B) a vinyl copolymer (I) obtained by copolymerizing another vinyl monomer copolymerizable with (B), and a hydrolysis promoting catalyst (II) excluding amines or carboxylic acid metal salts Wherein the copolymer (I) comprises: a hydroxyl group generated by decomposition of a siloxy group introduced by the monomer (A); The present invention relates to a so-called self-curing type coating resin composition having reactivity with an isocyanate group introduced by a monomer (B). [Prior Art] In recent years, plasticization of outer plates, parts, and the like has been rapidly progressing in the automobile industry and the home appliance industry. Conventionally, when the material is a steel plate, a baking one-pack type paint using an aminoplast-based curing agent as a main component such as an acrylic resin or an Alkit resin has been usually adopted as a paint to be used. However, when the material is made of plastic, some materials have a low heat-resistant temperature, and it is inappropriate to use a conventional one-component baking paint having a high baking temperature of 140 to 150 ° C. for plastic. Therefore, room temperature-curable and low-temperature curable paints have been studied or partially adopted for plastics. Examples of these paints include urethane paints composed of a combination of a polyol type resin and an isocyanate prepolymer, and 3 paints.
There are an epoxy-based coating of a combination of an acrylic resin having a secondary amino group and a polyfunctional epoxy resin, and a curing-type coating with aminoplast using a low-temperature curing catalyst such as paratoluenesulfonic acid. However, among these paints, urethane-based paints and epoxy-based paints that can be cured at room temperature are both two-pack type paints and have major drawbacks in workability such as pot life. On the other hand, aminoplast-curing paints using a low-temperature curing catalyst are in a one-part form because the main agent and the curing agent are pre-mixed, but the baking temperature is about 110 ° C. even if it is lower than before. Therefore, it was unsuitable for plastics. In addition, if an isocyanate prepolymer obtained by blocking an isocyanate prepolymer with an appropriate blocking agent is used, a one-pack type polyol resin-blocked isocyanate prepolymer curing system is obtained, but at present, the dissociation temperature of the blocking agent is 150 ° C. or higher. It is hard to say that it is a high-temperature, low-temperature or low-temperature curable resin system. [Problems to be Solved by the Invention] As described above, in the industry, from the viewpoint of coating workability, or from the viewpoint of material conversion and energy saving, etc., the long-term storage stability of In fact, there is a demand for the rapid development of so-called low-temperature-curable paints, which are excellent in various physical properties, weather resistance, etc., at room temperature or at about 110 ° C. or lower. Therefore, the problem to be solved by the present invention is that, while having excellent storage stability, it is also excellent in the balance of various physical properties of the coating film, and that it is particularly excellent in low-temperature curability,
An object of the present invention is to obtain an extremely practical coating resin composition. [Means for Solving the Problems] However, the present inventors have solved the present invention in order to provide a vinyl paint having extremely high practicality in accordance with the above-mentioned requirements or various demands. As a result of intensive studies with an eye on the problem to be solved, a vinyl monomer (A) having at least one polymerizable unsaturated double bond and a siloxy group in one molecule, respectively.
And a specific copolymer obtained using a vinyl-based monomer (B) having at least one polymerizable unsaturated double bond and an isocyanate group in one molecule,
Surprisingly, they have found that such various required properties can be improved, and as a result, they are not only excellent in storage stability and curability, but also in particular, are excellent in balance of various physical properties of the coating film, and are particularly excellent in low-temperature curability. The present invention has now been completed by finding that an extremely practical coating resin composition can be obtained. That is, the present invention basically comprises a vinyl copolymer (I) and a hydrolysis-promoting catalyst (II) excluding amines or metal salts of carboxylic acids, respectively. Is a vinyl monomer (A) having at least one polymerizable unsaturated double bond and a siloxy group in one molecule.
And 1 to 99% by weight of a vinyl monomer (B) having at least one polymerizable unsaturated double bond and an isocyanate group in one molecule.
If necessary, it can be obtained by copolymerizing the above (A) and (B) with 0 to 98% by weight of another vinyl monomer (C) copolymerizable therewith. In the coating resin of the present invention, a siloxy group introduced from a vinyl monomer (A), which is one of the constituent components of the resin, is reacted with moisture in the air to generate a hydroxyl group. Which reacts with an isocyanate group introduced from a vinyl monomer (B), which is the other component, to form a strong coating film, thereby providing excellent storage stability and excellent low-temperature curability. A liquid self-curing coating resin can be provided. Here, as the vinyl monomer (A), vinyl containing at least one polymerizable unsaturated double bond in one molecule and a siloxy group typically bonded to a carbon atom represented by the following formula: It is a system monomer. The method for producing the vinyl monomer (A) is not particularly limited, but may be, for example, trialkylchlorosilane, triphenylchlorosilane, triallylchlorine in the presence of a hydrochloric acid scavenger such as triethylamine or pyridine. A product obtained by reacting a silane, a dialkylchlorosilane, a dialkyldichlorosilane, a dialkylhydrosilane, or the like with a hydroxyl group-containing vinyl monomer as described below is referred to, and among them, trimethylsiloxyethyl (meth) is representative. ) Acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate, triethylsiloxyethyl (meth) acrylate,
Examples include tributylsiloxypropyl (meth) acrylate or triphenylsiloxyalkyl (meth) acrylate. These can be used alone or as a mixture of two or more. Examples of the hydroxyl group-containing vinyl monomer used in the production of the vinyl monomer (A) include β-hydroxyethyl (meth) acrylate, β-hydroxypropyl (meth) acrylate, and β-hydroxybutyl (meth) acrylate. Hydroxyalkyl (meth) acrylates or N-methylolated (meth) acrylamide; β-hydroxyethyl (meth) acrylate with ε-caprolataton added; polypropylene glycol monomethacrylate polyethylene glycol monomethacrylate; (meth) acryl Unsaturated carboxylic acids such as acid, maleic acid, fumaric acid or itaconic acid and glycidyl esters of branched fatty acids, glycidyl octylate or glycidyl coconut oil Typical examples include adducts with monoepoxy compounds represented by monoglycidyl esters of monovalent carboxylic acids or monoglycidyl ethers such as butyl glycidyl ether, and these hydroxyl group-containing vinyl monomers are used alone. Alternatively, they can be used as a mixture of two or more. The amount of the vinyl monomer (A) used is preferably 99 to 1% by weight, and more preferably 90 to 5% by weight. 1% by weight
If it is less than 1, the effect of the monomer cannot be expected. Next, as the other vinyl monomers (B) constituting the coating resin of the present invention, at least one vinyl monomer per molecule is used.
It is a vinyl monomer having one polymerizable unsaturated double bond and an isocyanate group. Typical examples are isocyanate ethyl (meth) acrylate, isocyanate propyl (meth) acrylate, isocyanate butyl (meth) acrylate, vinyl isocyanate, isopropenyl isocyanate, and 2-hydroxyethyl (meth) acrylate in which 1 is a bifunctional isocyanate. Mole: Isocyanate group-containing (meth) acrylate monomer obtained by addition in 1 mole is exemplified. Representative difunctional isocyanates which may be used in this case are aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate or xylylene diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate or trimethylhexane diisocyanate; There are alicyclic diisocyanates such as isophorone diisocyanate, methylcyclohexane-2,4- (or 2,6-) diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate or 1,3-di (isocyanatomethyl) -cyclohexane. The vinyl monomer (B) can be used alone or as a mixture of two or more kinds. If the amount is less than 1% by weight, the effect of the monomer cannot be expected.Next, a vinyl type copolymerizable with the vinyl type monomers (A) and (B) Typical examples of the monomer (C) include alkyl (meth) acrylates having 1 to 22 carbon atoms, styrene, vinyltoluene, t-butylstyrene,
α-methylstyrene, glycidyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (meth) acrylonitrile, cyclohexyl (meth) acrylate, maleic acid or fumaric acid and C _{1 to} C ₁₈ 1
Diesters with polyhydric alcohols, N, N-dialkylaminoalkyl (meth) acrylates, or phosphoric acid group-containing (meth) acrylates, and fluorine-containing vinyl monomers such as vinyl acetate, hexafluoropropylene, and tetrafluoroethylene. is there. These vinyl monomers (C) can be used alone or as a mixture of two or more thereof depending on the desired coating film performance, and the amount used is 0 to 98% by weight. Further, in the coating resin of the present invention, the above (A),
In addition to the use ratio of each monomer component of (B) and (C),
Hydroxyl group (-OH) generated from vinyl monomer (A)
Group of vinyl monomer (B) and isocyanate group (-NC
OH / NCO = 1 / 0.2 to 1/3 (equivalent ratio)
Should be within the range. The vinyl copolymer of the present invention can be obtained by a known and publicly known method using the above-mentioned monomers, typically by a solution polymerization method using, for example, a radical generator. As the radical generator used in the polymerization, any one can be used as long as it is generally used for the polymerization of a vinyl monomer.Among them, azobisisobutyronitrile, Di-tert-butyl peroxide or benzoyl peroxide; and as a solvent, aromatic hydrocarbons such as toluene or xylene; acetates such as ethyl acetate, butyl acetate or cellosolve acetate; methyl ethyl ketone or methyl isobutyl Ketones such as ketones can also be used. If necessary, a commonly used chain transfer agent such as mercaptans, α-methylstyrene and dipentene can also be used. The coating resin of the present invention thus obtained preferably has a number average molecular weight (n) of 500 to 50,000. When n of the resin is less than 500, the physical properties of the coating film cannot be sufficient, and the hydroxyl value generated after the trialkylsiloxy group or the like of the resin is released in order to obtain the physical properties of the coating film. (Hereinafter, this is referred to as "OH value.")
Higher is not preferable because the coating film becomes brittle, and conversely
If it exceeds 50,000, defects tend to appear in the appearance, gloss, texture, coating workability and the like of the coating film, which is not preferable. Next, the curing performance of the vinyl-based copolymer (I), which is one of the essential components constituting the coating resin composition according to the present invention, which is a coating resin, is further enhanced. In order to achieve a coating resin composition that can be cured even in a low temperature range of about 100 ° C or lower,
It is necessary to use a hydrolysis promoting catalyst (II) as another component of the essential components constituting the coating resin composition according to the present invention, and the hydrolysis promoting catalyst ( As II), various compounds in the form excluding the amines or the metal carboxylate, respectively, are applicable. As typical examples of such catalysts, phosphoric acid, phosphoric acid ester or phosphite or p-toluenesulfonic acid or an amine salt thereof (D-1); benzoic acid, Trichloroacetic acid, trifluoroacetic acid or naphthalenesulfonic acid or amine salts thereof (D-2); various sulfide-type or mercaptide-type organotin compounds such as monobutyltin sulfide or dioctyltin methylcaptide (D-
3); or various compounds generating fluorine ions, such as tetraethylammonium fluoride or cesium fluoride. The amount of these hydrolysis-promoting catalysts to be used is as follows, based on the above-mentioned vinyl copolymer (I), which is a coating resin.
The range of about 0.001 to about 10% by weight is preferably 0.005 to about 10% by weight.
The range of ８8% by weight is appropriate. The vinyl copolymer (I) as a coating resin, which is one of the essential components constituting the coating resin composition according to the present invention obtained as described above, is not exposed to the atmosphere unless it is exposed to the atmosphere. Since no hydroxyl group capable of reacting with the curing agent is generated, the coating resin composition of the present invention is a one-pack type, and provides a paint having good stability. However, in order to ensure long-term storage stability, a small amount of water that enters for some reason may be captured. That is, long-term stability is ensured by adding a water binder reactive with moisture. In addition, the water binder may be mixed and used in the initial stage of the production of the coating resin. Examples of the water binding agent having reactivity with water include trialkyl orthoformates such as trimethyl orthoformate, triethyl orthoformate and tributyl orthoformate; trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate. Trialkyl orthoborates such as tributyl orthoborate and triethyl orthoborate; tetra (substituted) such as tetramethylsilicate, tetraethylsilicate, tetrabutylsilicate, tetra (2-methoxyethyl) silicate or tetra (2-chloroethyl) silicate Alkyl silicates alone; the same active substances as the above tetra (substituted) alkyl silicates such as tetraphenyl silicate and tetrabenzyl silicate (hereinafter abbreviated as the same effective single units); or tetraethyl The above-mentioned tetra (substituted) alkyl silicates alone such as dimer, trimer, tetramer, hexamer of silicate and a mixture of tetramer, pentamer and hexamer of tetraethyl silicate, and a hydrolyzate such as a condensate of the same effective silicate alone There are decomposable ester compounds, compounds having an isocyanate group such as phenyl isocyanate, p-chlorophenyl isocyanate, benzenesulfonyl isocyanate, p-trienesulfonyl isocyanate, isocyanate ethyl methacrylate, and the like. The amount used is 0.1 to 30% by weight, preferably 0.5 to 20% by weight, based on the coating resin. The coating resin composition according to the present invention thus obtained can be used in the form of a solution, a non-aqueous dispersion, or a powder. In addition, it can be used in a wide variety of applications such as automobiles, home appliances and building exteriors, as well as for precoating of metals, but the effect is remarkable especially in the field of one-pack type requiring storage stability. It is. Next, the present invention will be described in detail with reference to Examples and Examples. In the following, all parts and percentages are by weight unless otherwise specified. Reference Example 1 300 parts of trimethylsiloxyethyl methacrylate,
100 parts of styrene, 230 parts of isocyanatoethyl methacrylate, of n- butyl methacrylate 270 parts and SL- methacrylate (monomer mixture consisting of methacrylate 100 parts with alkyl C ₁₂ -C ₁₃ manufactured by Mitsubishi Rayon Co. 200 parts, toluene 500 parts, isobutyl acetate 200 parts, azobisisobutyronitrile (AIBN) 5
And 10 parts of tert-butyl perbenzoate (t-BPB) were placed in a four-necked flask equipped with a stirrer, an inert gas inlet, a thermometer and a condenser, kept at 90 ° C. for 1 hour, and then kept at 30 ° C. for 1 hour. It takes a minute to raise the temperature to 115 ° C, and at the same temperature 800 parts of the remaining monomer mixture and 300 parts of isobutyl acetate, t-BPB1
By holding a mixture of 0 parts and 5 parts of AIBN, a resin solution (1) having a nonvolatile content of 50.1%, a particle size (Gardner viscosity at 25 ° C .; the same applies hereinafter) Z ₂ -Z ₃ , and a number average molecular weight of 12,000 was obtained. Reference Example 2 1 mol of β-hydroxyethyl methacrylate
Reaction product of a hydroxyl group-containing vinyl monomer to which mol ε-caprolactone is added and trimethylchlorosilane 25
0 parts, styrene 100 parts, n-butyl methacrylate 175
Parts, isobutyl methacrylate 174 parts, n-butyl acrylate 100 parts, SL-methacrylate 150 parts, methacryloyl isocyanate was changed to use 51 parts, by the same operation as in Reference Example 1, nonvolatile content 49.8%,
A resin solution (2) having a viscosity ST and a number average molecular weight of 13,000 was obtained. Reference Example 3 Triphenylsiloxyethyl methacrylate 250
Parts, styrene 400 parts, n-butyl methacrylate 100
Parts, n-butyl acrylate 54 parts, and isocyanate butyl methacrylate 196 parts, except that the nonvolatile content was 49.9, the viscosity was 49.9
A resin solution having a ZZ ₁ and a number average molecular weight of 1300-(3) was obtained. Reference Example 4 The same operation as in Reference Example 1 was conducted except that 200 parts of trimethylsiloxyethyl acrylate, 400 parts of methyl methacrylate, 235 parts of n-butyl methacrylate, and 165 parts of isocyanate ethyl methacrylate were used. 50.3%, viscosity Z ₂ -Z ₃ , number average molecular weight 130
A resin solution No. 00- (4) was obtained. Example 1 In 100 parts of the resin solution (1) obtained in Reference Example 1, 0.1 part of trichloroacetic acid, 1.0 part of p-toluenesulfonyl isocyanate, and "Taipeku CR-93" [manufactured by Ishihara Sangyo Co., Ltd.] Is a trade name of rutile-type titanium oxide, and “Taipec” is a registered trademark of the same company. 20 parts), and then, in accordance with a conventional method, made into a paint,
Thereafter, the paint thus obtained was spray-coated on a zinc phosphate-treated steel sheet and baked at a temperature of 110 ° C. After the baking, the cured coating film thus obtained was allowed to stand at room temperature for 3 days, and a test for evaluating the properties of the cured coating film thus obtained was performed. That is, gloss by 60 degree mirror reflectance (60 degree reflectance:
%) Is 92, the pencil hardness is F, and the adherence by peeling of cellophane tape from Goban (cellophane from Goban)
The tape peeling) was 100/100, and the alkali resistance (5%) was determined by immersing the film in a 5% aqueous NaOH solution for 24 hours and then visually checking the state change of the coating film. NaOH, 24 hours) and acid resistance (5% H ₂ SO 5) by visually determining the change in state of the coating film after immersion in a 5% H ₂ SO ₄ aqueous solution for 24 hours. SO ₄ , 24 hours)
No abnormality was found. In addition, the storage stability of the paint itself, as determined by standing at room temperature for 3 months, did not gel. Examples 2 to 7 In order to evaluate various physical properties of the resin solution obtained in each of the reference examples, a composition having the composition shown in Table 1 was used as a coating according to a conventional coating method, and then as shown in the table. A physical property test was performed for each of the items. The results are summarized in the same table. [Effects of the Invention] The coating resin of the present invention is a self-curing resin having excellent low-temperature curability and also excellent storage stability, and a coating film obtained from such a resin has gloss, It also has excellent coating appearance.

Continuation of front page (56) References JP-A-62-250017 (JP, A) JP-A-63-30512 (JP, A) JP-A-64-75578 (JP, A) (58) Fields studied (Int .Cl. ⁶ , DB name) C09D 143/00 C09D 139/00 C09D 133/06 C09D 175/00 C09D 175/04

Claims (1)

(57) [Claims] 99-1% by weight of the vinyl monomer (A) having at least one polymerizable unsaturated double bond and siloxy group in one molecule, and at least one polymerizable monomer in one molecule, respectively. 1 to 99% by weight of the vinyl monomer (B) having an unsaturated double bond and an isocyanate group
And, if necessary, the above (A) and (B)
A vinyl copolymer (I) obtained by copolymerizing 0 to 98% by weight of a copolymerizable vinyl monomer (C) other than the above, and phosphorus, excluding amines or carboxylic acid metal salts, respectively. Acid, phosphoric acid ester or phosphite or p-toluenesulfonic acid or an amine salt thereof (D-1); benzoic acid, trichloroacetic acid, trifluoroacetic acid, naphthalenesulfonic acid or an amine salt thereof (D- 2); a sulfide-type or mercaptide-type organotin compound (D-3); or a hydrolysis-promoting catalyst (I) represented by a compound (D-4) that generates fluorine ions.
(I) A coating resin composition comprising: