JPH0680155B2 - Resin composition for paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a newly useful resin composition for coatings, and more specifically, a specific active hydrogen-containing compound having a triazine ring and a polyisocyanate are essential. The present invention relates to a resin composition for a two-pack type urethane coating, which is contained as a component.

[Conventional technology]

2. Description of the Related Art Conventionally, two-component urethane paints have been widely used as woodworking furniture paints, anticorrosion paints, automobile repair paints, etc. because they are fast-curing, have strong coating film performance, and have excellent durability.

By the way, this type of two-component urethane coating composition is generally composed of active hydrogen-containing compound as a main component, generally polyol, and polyisocyanate as a curing agent.

Of these, alkyd polyols, polyester polyols, acrylic polyols, etc. have been frequently used as polyols, but first of all, alkyd polyols are excellent in pigment dispersibility, luster and texture,
Although it is mainly used as a paint for woodwork furniture, it has a short pot life when compounded with polyisocyanate, making it difficult to achieve high solids.

Polyester polyols have a long pot life and exhibit excellent coating properties, but on the other hand, they have poor drying properties.
Furthermore, although acrylic polyol has excellent drying properties and is widely used in exterior paints and automobile repair paints, it has the drawback that the pigment dispersibility is poor and that a coating film with a gloss and a long-lasting feeling cannot be obtained.

Therefore, it is possible to use the respective polyols by blending them in order to compensate for the various drawbacks of the respective polyols, but the compatibility between the respective polyols is extremely limited.

In addition, it is a fibrous material that is superior in weather resistance to such two-component urethane paints, and is also excellent in leveling property and “sagging” stopping property, mainly 1/2 second cellulose acetate butyrate (1/2 ″ CAB Although there is a need to use)), the compatibility with 1/2 ″ CAB also exists in the fact that most of these polyols, most of all, alkyd polyols are not compatible with each other.

[Problems to be solved by the invention]

Therefore, it has a pigment dispersibility, gloss, and a feeling of flesh comparable to that of an alkyd polyol, and has a pot life and coating performance comparable to that of a polyester polyol, and also has a drying property comparable to that of an acrylic polyol. Liquid urethane paint has not been obtained at present.

Thus, as long as the conventional technology is followed, it has pigment dispersibility, gloss, flesh feeling, coating performance and pot life comparable to existing polyols, especially alkyd polyols. The fact is that no truly practical two-component urethane paint has been found that has compatibility with various resins such as resin and fibrin, and also has good drying property. Is.

Therefore, the problem to be solved by the present invention is to overcome the technical situation as described above and solve the problem.

[Means for solving problems]

However, in view of these circumstances, the present inventors have the pigment dispersibility, gloss / flesh feeling, coating film performance and pot life comparable to those of respective polyols, and further, with resins such as acrylic polyol and fibrin. As a result of earnest research to provide a two-component urethane coating that is compatible with each other and can improve the drying property, as a main ingredient, a specific active hydrogen-containing compound called an alkyd-modified active hydrogen-containing compound having a triazine ring in the molecule As a result, the present invention has been completed by finding a resin composition for a coating that meets such an intended purpose.

That is, the present invention, as an essential component, the general formula A triazine-based amino compound, formaldehyde, a polyol, and a fatty acid, a polyvalent carboxylic acid and a polyhydric alcohol, and 50-100 of the fatty acid.
An alkyd resin having a hydroxyl group with an average number of hydroxyl groups per molecule of 1 to 2.5, which is characterized by containing saturated fatty acids in a weight percentage, and a triazine ring obtained by co-condensing a monohydric alcohol if necessary. With the active hydrogen-containing compound and the (B) polyisocyanate as essential components, the solid content weight ratio of these (A) and (B) components is (A) /
(B) = 5/95 to 95/5, so that the resin composition for coating composition, more specifically, the average number of hydroxyl groups per molecule is 1 to
The alkyd resin having a hydroxyl group of 2.5 is composed of a fatty acid, a polycarboxylic acid and a polyhydric alcohol, and
50-100% by weight of a saturated fatty acid, and 30-100% by weight of the polyvalent carboxylic acid is an aromatic polyvalent carboxylic acid and / or an alicyclic polyvalent carboxylic acid. It is to provide things.

Here, the above-mentioned triazine-based amino compound refers to the compound represented by the above-mentioned general formula [I], and the most typical compound among them is melamine, benzoguanamine or acetoguanamine, but of course, formoguanamine. , Propioguanamine or isopropylguanamine can also be used, and these granamine compounds can be used alone or as a mixture of two or more kinds.

Since these guanamine compounds are generally synthesized from dicyandiamide and a nitrile compound [eg, Nomura, Ta, Kakurai, Noguchi; “Synthetic Organic Chemistry”, Vol. 24, No. 2, p. 125 (1966)] Various kinds of guanamine having different substituents can be obtained depending on the kind.

It is well known that the triazine-based amino compound reacts with formaldehyde to form a methylol compound, and the number of amino groups in the compound determines the upper limit of the number of moles of formaldehyde to react.

That is, since 2 mol of formaldehyde is added to one amino group to generate two methylol groups, if the number of amino groups bonded to the triazine ring is n (for example, in the case of guanamines, n = 2, and in the case of melamines, n = 3), and a maximum of 2 nmoles of formaldehyde will be added to this triazine-based amino compound.

At this time, it is appropriate that the amount of formaldehyde used is in the range of n to 20n with respect to 1 mol of the compound,
If the amount is less than nmol, the reactivity with the following polyhydric alcohol is lowered, which is not preferable. On the contrary, if the amount exceeds 20nmol, the obtained cocondensate (triazine ring-containing polyol) is obtained.
The free formaldehyde content (unreacted content) in the solution increases, which is not preferable.

Particularly preferable amount of formaldehyde used is 2n ± 1
Within the range of molar.

In the present invention, in addition to the above-mentioned formaldehyde, various aldehydes such as acetaldehyde, propioaldehyde, glyoxal, succinic acid aldehyde, and chloral may be used in combination if necessary.

Typical examples of the above-mentioned polyols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, butanediol, pentanediol, neopentyl glycol, hexanediol, 2,2,4- Polyhydric alcohols such as trimethyl-1,3-pentanediol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol or sorbitol,
Bisphenols, hydrogenated bisphenols or halogenated bisphenols, and further addition compounds of various polyhydric alcohols and alkylene oxides fried above and various polyhydric alcohols or bisphenols and polybasic acids Polyester obtained by the reaction of.

Other than these, hydroxyl group-containing fatty acid ester polyols such as alcoholysis reaction products of various oils and fats and various polyols, or esterification reaction products of various higher fatty acids and various polyols or epoxy compounds, and castor oil are also used. it can.

Of course, these polyols can be used alone or in the form of a mixture.

Further, the above-mentioned alkyd resin having a hydroxyl group is one molecule characterized by being obtained by the reaction of a fatty acid, a polyvalent carboxylic acid and a polyhydric alcohol, and 50 to 100% by weight of the fatty acid is a saturated fatty acid. The average number of hydroxyl groups per hit is 1
An alkyd resin having a hydroxyl group of 2.5, specifically consisting of a fatty acid, a polycarboxylic acid and a polyhydric alcohol, and 50 to 100% by weight of the fatty acid is a saturated fatty acid, and 30 to 100 of the polycarboxylic acid. An alkyd resin having a hydroxyl group with an average number of hydroxyl groups per molecule of 1 to 2.5, which is characterized in that the weight% is an aromatic polycarboxylic acid and / or an alicyclic polycarboxylic acid, is first designated as a fatty acid. Typical examples include those obtained from natural oils and fats such as coconut oil fatty acid, castor oil fatty acid, safflower oil fatty acid, soybean oil fatty acid, rice bran oil fatty acid or tall oil fatty acid, or versatic acid or "PAMOLYN". ) ”(Product of Hercules, Inc.)
On the other hand, typical polyvalent carboxylic acids include phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid,
Examples include tetrahydrophthalic anhydride, hexahydrophthalic anhydride or adipic acid.

In addition to this, it is perfectly acceptable to use benzoic acid or tertiary butyl benzoic acid together.

Furthermore, the above-mentioned alkyd resin having a hydroxyl group refers to, for example, one prepared by the method shown below.

That is, a method of transesterifying oils and fats with a polyol as described above by a conventional method and then performing an esterification reaction by a conventional method using a polycarboxylic acid as described above, or a fatty acid and a polyol as described above respectively. And a polycarboxylic acid are used to carry out an esterification reaction by a conventional method.

In any of these methods, the desired hydroxyl group-containing alkyd resin can be obtained, but as the alkyd resin thus obtained, firstly, the average number of hydroxyl group functional groups per molecule is 1 to 2.5. Those within the range are suitable. If it is less than 1, a large amount of the alkyd resin, which is a plasticizing component that does not react with the polyisocyanate (B), remains in the finally obtained two-component urethane coating film, and as a result, the drying property deteriorates significantly. On the contrary, when it exceeds 2.5, the content of the active hydrogen-containing compound is rapidly increased during the synthesis of the triazine-containing active hydrogen-containing compound using the triazine-based amino compound, formaldehyde, polyol, and hydroxyl group-containing alkyd resin. The viscosity of the reaction system increases sharply due to the increase in the degree of branching of the compound,
Therefore, it becomes difficult to obtain a desired viscosity.

Secondly, it is preferable that the aromatic and / or alicyclic polycarboxylic acid accounts for 30 to 100% by weight of the polycarboxylic acid which is one of the raw materials of the alkyd resin. that is,
As the molecular structure of the alkyd resin, those aromatic and / or alicyclic polycarboxylic acids having a rigid structure are
The amount is preferably 30% by weight or more, and when the amount of the aliphatic carboxylic acid exceeds 70% by weight, the drying property is deteriorated and the coating film becomes extremely soft.

Third, as the fatty acid which is one of the raw materials of the alkyd resin, 50% by weight or more is preferably a so-called saturated fatty acid having no carbon-carbon double bond in the molecule. This is because it is difficult to obtain an active hydrogen-containing compound having a triazine ring, which is less colored, and thus the coating film finally obtained is also easily colored with time. This is because the viscosity stability of the compound over time is also lost.

In preparing the active hydrogen-containing compound having a triazine ring described above, a monohydric alcohol can be further used if necessary. Typical examples of the monohydric alcohol include methanol and ethanol, Aliphatic alcohols such as propanol, butanol, amyl alcohol or octanol; alicyclic alcohols such as cyclohexanol; or aromatic alcohols such as benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, Various ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether or tetrahydrofurfuryl alcohol. There is such as alcohols (cellosolves).

Next, a method for preparing an active hydrogen-containing compound having a triazine ring using the above-mentioned various raw material compounds will be illustrated as follows.

That is, (1) a method of using an alkoxymethylated triazine-based amino compound as a starting material and (2) a method of simultaneously reacting a triazine-based amino compound, formaldehyde and a polyol are mentioned as typical ones. The above-mentioned alkoxymethylated triazine-based amino compound has the general formula Or general formula Indicated by.

Provided that at least one of R ₁ , R ₂ , R ₃ or R ₄ or R ₅ or R ₆ bonded to the nitrogen atom in the formula [II] or [III] is a methylol group and / or Or it must be an alkoxymethyl group.

Of these, a methoxy, ethoxy or butoxy group is preferable as the alkoxyl group (—CH ₂ OR ₇ ), but it goes without saying that a mixed form thereof may be used.

Further, each compound represented by the above general formula [II] or [III] does not necessarily have to be a simple substance, and needless to say, may be a compound obtained by multimerization with a methylene bond or a dimethylene bond. is there.

Further, the alkoxymethylated triazine-based amino compound preferably has at least three alkoxymethyl groups per one triazine nucleus, and it is particularly preferable to use hexamethoxymethylmelamine.

Thus, the reaction of the alkoxymethylated triazine-based amino compound with the above-mentioned polyol and the hydroxyl group-containing alkyd resin is carried out in the presence or absence of a catalyst without using a solvent or in a non-reactive solvent. Done.

Although no particular catalyst is required, when used, well-known and commonly used Lewis acids, mineral acids, formic acid, oxalic acid, maleic anhydride, phthalic anhydride monoalkyl ester, phenylsulfonic acid, p-toluenesulfonic acid, Organic acids such as tetrachloroacetic acid or tetrachlorophthalic anhydride monoalkyl ester, or metal alcoholates such as sodium methylate can be used.

Further, although the reaction product is dissolved with the non-reactive solvent described above,
We refer to something that does not interfere with the alcohol exchange reaction,
In addition to alcohol solvents such as aromatic hydrocarbon solvents such as benzene, toluene and xylene, various ester solvents, ether solvents or ketone solvents can be used.

Thus, the alcohol exchange reaction varies depending on the presence or absence of a catalyst, but in the temperature range of 50 to 180 ° C., preferably 80 to 150 ° C., while carrying out dealcoholization under normal pressure or reduced pressure, it takes 1 to 20 hours. It is preferable to complete it.

A high temperature reaction at 180 ° C. or higher using a strongly acidic catalyst is not common because it accelerates the self-condensation of the alkoxymethylated triazine-based amino compound.

The active hydrogen-containing compound (A) having a triazine ring thus obtained can be prepared by the method (2) described above, and the method (2) is one step of the method (1) described above. Since it is a production method, it can be obtained at a low price because no intermediate raw material (intermediate) is used. Therefore, when using formalin (formaldehyde aqueous solution), a heterogeneous system can be obtained in an organic solvent. It has the advantage that polyhydric alcohols such as pentaerythritol or dipentaerythritol can be reacted in a homogeneous system. However, on the other hand, in the final resin, that is, in the solution of the active hydrogen-containing compound having a triazine ring, unreacted formaldehyde is likely to remain, and further, the degree of condensation of the final triazine-based resin is likely to be increased, which is a drawback. is there.

The reaction in preparing the active hydrogen-containing compound having the triazine ring proceeds by removing water and / or alcohol, and in order to facilitate the removal of such substance, benzene, toluene, xylene, or the like is used. Aromatic hydrocarbons can also be used as entrainers.

In that case, the solvent of the final triazine-based resin should be replaced with a solvent which is non-reactive with the polyisocyanate (B) curing agent by either of the above-mentioned methods (1) and (2).

As such non-reactive solvent, there are various solvents as mentioned in the above-mentioned method (1), but among them, toluene or xylene is used alone, or with these, ethyl acetate and / or butyl acetate. It is recommended to use in combination with.

The polyisocyanate (B) which is another component constituting the coating resin composition of the present invention means 1,6-hexamethylene diisocyanate, 1,8-octamethylene diisocyanate, 1,2-dodecamethylene diisocyanate or
Alkylene diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate, 3,3'-diisocyanate dipropyl ether, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, cyclopentylene-1,3-diisocyanate , Cyclohexylene-1,4-diisocyanate, methyl-2,6-
Diisocyanate caproate, bis (2-isocyanatoethyl) fumarate, 4-methyl-1,3-diisocyanate cyclohexane, trans vinylene diisocyanate and similar unsaturated isocyanates; 4,4'-methylene bis (cyclohexyl isocyanate), methane diisocyanate, N , N ', N "-Tris (6-isocyanatohexamethyl) bullet or aliphatic or cycloaliphatic polyisocyanates such as bis (2-isocyanatoethyl) carbonate and similar diisocyanates; toluene diisocyanate, xylylene diisocyanate, dianisidine diisocyanate , 4,4'-diphenylmethane diisocyanate, 1-ethoxy-2,4-
Aromatic polyisocyanates such as diisocyanate benzene, 1-chloro-2,4-diisocyanate benzene, tris (4-isocyanatephenyl) methane, naphthalene diisocyanate, fluorein diisocyanate or 4,4'-biphenyl diisocyanate; further phenylene diisocyanate, 3,3'-dimethyl-
There are 4,4'-biphenyl diisocyanate, p-isocyanate benzyl isocyanate, tetrachloro-1,3-phenylene diisocyanate, etc., and one or two of these
A mixture of one or more species may be used, and an isocyanate-terminated prepolymer which is a reaction product of the above-mentioned various polyisocyanates with a low molecular weight polyhydroxy compound or polyamine compound may also be used.

Among these, as the low molecular weight polyhydroxy compound, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, 1,4-butanediol, hexane methylene glycol, neopentyl glycol, polyethylene adipate glycol,
Polybutylene adipate glycol and other polyester polyols, glycerin, trimethylol propane, polyhydric alcohols such as pentaerythritol are typical examples, on the other hand, as the low molecular weight polyamine compound, ethylenediamine, propylenediamine,
Hexamethylenediamine and the like are typical examples. Further, the above-mentioned organic polyisocyanate is an isocyanuric ring-containing polyisocyanate obtained by polymerizing using a polymerization catalyst such as a metal catalyst or a quaternary ammonium salt, and a burette type of the above-mentioned organic polyisocyanate buretted with water. Polyisocyanates are also used.

The coating resin composition of the present invention comprises an active hydrogen-containing compound (A) having a triazine ring and a polyisocyanate (B) as essential components, and the compounding ratio thereof is B / A = 5 / A value of 95-95 / 5 (% by weight of solid content) is suitable.

The isocyanate group in the polyisocyanate reacts with the amino group, imino group, methylol group and hydroxyl group in the triazine-based resin to form a coating film having a three-dimensional network structure, which depends on the functionality, purpose and application of each. The mixing ratio of B / A should be selected arbitrarily.

When the blending ratio of the polyisocyanate (B) is less than 5% by weight, the crosslink density is small and sufficient coating film performance cannot be obtained. Further, when the compounding ratio of the active hydrogen-containing compound (A) is less than 5% by weight, the composition does not have desired performance. The compounding ratio of polyisocyanate (B) is 20
It is preferably used in the range of 50% by weight.

The composition of the present invention can be used in either clear paint or enamel paint, and the composition of the present invention may be made into a paint according to a conventional method. Furthermore, the type and amount of the pigment, paint auxiliary agent or curing catalyst and the like used. May also be known and conventional.

〔Example〕

Next, the present invention will be described more specifically with reference to Examples.
In the following, all parts are parts by weight unless otherwise specified.

Reference Examples 1 to 9 (Preparation Example of Alkyd Resin Having Hydroxyl Group) Oils and fats, active hydrogen-containing compounds and acid components as shown in Table 1 were charged at a predetermined ratio, and transesterification reaction and / or reaction was carried out in the usual way An esterification reaction was performed to obtain the target resin.

The average hydroxyl functionality of each hydroxyl group-containing alkyd resin is summarized in the same table.

Reference Examples 10 to 21 A thermometer, a stirrer, and a bifurcated connecting pipe (T-shaped pipe) for desolvation, to which one of a Liebig cooling pipe and a collector was connected, "Cymel # 300" [Mitsui Hexamethoxymethylol melamine manufactured by Cyanamid Co., Ltd.], a hydroxyl group-containing alkyd resin, and if necessary, a polyol and a solvent are added in the proportions shown in Table 2, heated to 50 ° C., and then stirred, and then 1 The temperature is raised to 120 ° C. over time, and the alcohol exchange reaction proceeds while collecting and collecting the by-produced methanol and / or solvents by cooling.
Then, the temperature was lowered when a predetermined viscosity was reached, and the target compound was obtained by diluting with a solvent.

Examples 1 to 11 and Comparative Examples 1 to 5 Resin compositions of the present invention and control resin compositions were obtained by using the respective components in the compounding ratios shown in Tables 3 and 4.

The coating properties and coating film performance of each resin composition were compared and examined, and the results are summarized in each table.

The evaluation method at that time is as follows.

First, a paint is prepared by separately mixing active hydrogen-containing compounds having a triazine ring, polyisocyanate, and a diluent solvent of toluene / ethyl acetate / butyl acetate / cellosolve acetate = 1/1/1/1 (weight ratio). Then, each paint was applied by brush onto a commercial plywood.

Then, each coated plate was dried and cured at 20 ° C. for 7 days to obtain a cured coating film.

Dryability: Both touch drying and curing drying were in accordance with JIS K-5400.

Pot life: It was judged by the state of the blended liquid after 12 hours from the blending of the paint.

Pencil hardness: According to JIS K-5400.

Pigment dispersibility: PW composed of base polyol and carbon black
After kneading so that the C content is 20%, the remaining main component polyol, polyisocyanate and diluent solvent are mixed to form PW.
Judgment was made based on the gloss of the composition coated so that C was 5%.

◎: Excellent ○: Good △: Normal ×: Impossible × ×: Unusable Feeling of flesh: Determined visually.

◎: Excellent ○: Good △: Normal XX: No Compatibility with CAB: 10% by weight of resin (solid content conversion)
CAB was mixed so that

Repeated cold heat: According to Japanese Agricultural Standards (JAS) for special plywood, the evaluation was made by visually observing the degree of whitening of the coating film.

◎: Excellent ○: Good △: Normal ×: Impossible × ×: Unusable [Effects of the Invention] The composition of the present invention is quick-drying, has good gloss, sensation of feeling, pigment dispersibility and durability, and has excellent coating workability and high solidification. It is particularly suitable as a paint for woodworking or furniture, a paint for repairing automobiles, an anticorrosive paint, a paint for plastics, etc., and the composition of the present invention is more suitable than an alkyd polyol which has been widely used as a two-component urethane paint from the past. It is also possible to design a paint that gives a coating film with even more excellent gloss and flesh, and has a drying time that is almost the same as that of conventional alkyd polyols, but with a longer pot life.

Moreover, in the conventional alkyd polyol, it was almost impossible to use the blend in order to improve the gloss and suppleness of the acrylic polyol, which is excellent in drying property, and also to improve the pigment dispersibility. On the other hand, since the active hydrogen-containing compound having a triazine ring exhibits wide compatibility with this acrylic polyol, it is effective as a resin for modifying acrylic polyol, and therefore, the active hydrogen-containing compound having such characteristics is essential. The usefulness of the composition of the present invention, which is contained as one component, is remarkable.

Further, the active hydrogen-containing compound having such a triazine ring is used as a phase modifier with a fibrin useful as a modifier for a coating material such as CAB or a vinyl chloride / vinyl acetate copolymer such as "VAGH" (a product of Union Carbide Co., USA). The composition of the present invention has further usefulness because of its excellent solubility.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-50-135121 (JP, A) JP-A-47-17897 (JP, A) JP-B-3-73593 (JP, B2)

Claims (2)

[Claims] 1. A general formula (A) [However, X in the formula is _{-H, -CH 3, -C 2 H} 5, -C 3 H 7, -C
_It shall represent ₆ H ₅ or -NH ₂ . ] A triazine-based amino compound represented by, formaldehyde, a polyol, and a fatty acid, a polyvalent carboxylic acid and a polyhydric alcohol, and 50-100 of the fatty acid
An alkyd resin having a hydroxyl group with an average number of hydroxyl groups per molecule of 1 to 2.5, which is characterized by containing saturated fatty acids in a weight percentage, and a triazine ring obtained by co-condensing a monohydric alcohol if necessary. With the active hydrogen-containing compound and the polyisocyanate (B) as essential components, the solid content weight ratio of both components (A) and (B) is (A) / (B) = 5/95 to 95/5. A resin composition for coating, which comprises: 2. An alkyd resin having a hydroxyl group with an average number of hydroxyl groups per molecule of 1 to 2.5 is composed of a fatty acid, a polyvalent carboxylic acid and a polyhydric alcohol, and 50 to 100 of the fatty acid.
% By weight of saturated fatty acid, and 30 to 10% of the polycarboxylic acid.
The coating resin composition according to claim 1, wherein 0% by weight is an aromatic polycarboxylic acid and / or an alicyclic polycarboxylic acid.