JP2814515B2 - One-component low-temperature curable coating resin composition - Google Patents

Description

The present invention relates to a novel and useful low-temperature curable resin composition. More specifically, the present invention provides an essential coating of a low-temperature curable resin obtained by subjecting a specific carbonate group-containing copolymer and a specific aminosilane compound to an addition reaction by heating under moisture-free conditions. The present invention relates to a resin composition for a one-component low-temperature-curable coating material, which comprises a forming component.

[Conventional technology]

In recent years, acrylic lacquers and polyisocyanate-curable two-part urethane paints have been widely used as room-temperature drying paints with good weather resistance. Despite the merit, there is a drawback that the physical properties of the coating film are inferior to those of the crosslinked paint.

On the other hand, in the case of the latter polyisocyanate-curable two-pack urethane paint, there is a problem of toxicity caused by the isocyanate compound, and none of these is preferable.

[Problems to be solved by the invention]

Therefore, the development of a new curing system is urgently desired.

Therefore, the present inventors have conducted intensive studies in view of the existence of various disadvantages in the prior art as described above, and as a result, a specific carbonate group-containing copolymer and a specific aminosilane compound, no water at all In the system, a resin composition containing a hydrolyzable silyl group-containing resin as an essential film-forming component, which is obtained by heating and performing an addition reaction, has low-temperature curability, and balances various properties. The present invention has been completed by finding out that it has been used, in particular, it is useful for paints.

Therefore, the object of the present invention is to provide a coating resin composition having excellent low-temperature curability, and particularly to one of the series of inventions that can be cured with moisture such as moisture in the air. An object of the present invention is to provide a resin composition for a liquid type low temperature curable coating material.

[Means for solving the problem]

That is, the present invention firstly uses the general formula 0.2 to 90% by weight of the polymerizable monomer (a-1)
And another monoethylenically unsaturated monomer (a-2) copolymerizable with this monomer (a-1), the total amount of all monomers being
A carbonate group-containing copolymer (A) obtained by copolymerization so as to be 100% by weight, and a compound (B) having both one amino group and at least one hydrolyzable silyl group in one molecule. ), For example, in an atmosphere of a so-called inert gas such as nitrogen gas, that is, an essential film form of a hydrolyzable silyl group-containing resin obtained by performing an addition reaction by heating in a system free of moisture. An object of the present invention is to provide a resin composition which is excellent in low-temperature curability and which is useful as a one-pack type coating composition, which is contained as an active ingredient.

Here, first, only typical examples of the polymerizable monomer (a-1) used in preparing the above-mentioned carbonate group-containing copolymer (A) will be 2,3. -Carbonate propyl (meth) acrylate, 3,4-carbonate butyl (meth) acrylate, 4,5-carbonate pentyl (meth) acrylate, 5,6-carbonate hexyl (meth) acrylate or 6,7-carbonate heptyl (meth) Acrylate and the like.

The amount of the carbonate group-containing polymerizable monomer (a-1) to be used is in the range of 0.2 to 90% by weight, preferably in the range of 2 to 45% by weight, based on the total amount of all monomers. Inside is appropriate.

Further, as the copolymerizable monoethylenically unsaturated monomer (a-2), the polymerizable monomer (a
Any of those which can be copolymerized with -1) can be used. Among them, particularly typical ones are methyl (meth) acrylate, ethyl (meth) acrylate and (meth) acrylate. (Meth) acrylates of various monohydric alcohols such as butyl acrylate, 2-ethylhexyl (meth) acrylate or lauryl (meth) acrylate; styrene, α-methylstyrene, p-
various aromatic vinyl compounds such as tert-butylstyrene, dimethylstyrene or vinyltoluene; (meth) acrylamides such as (meth) acrylamide, N-methylol (meth) acrylamide or butoxy (meth) acrylamide or various derivatives thereof; Alternatively, various dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate or diethylaminoethyl (meth) acrylate, and further, (meth) acrylonitrile,
Vinyl acetate, diethyl maleate, dibutyl maleate, dibutyl fumarate, diethyl itaconate or dibutyl itaconate.

The carbonate group-containing copolymer (A) can be prepared using any of the above-listed monomers by any known and commonly used method. It is most convenient to use a law.

In that case, an aromatic hydrocarbon solvent such as toluene or xylene; a (cyclic) aliphatic hydrocarbon solvent such as pentane, hexane or cyclohexane; ethyl acetate;
Ester solvents such as n-butyl acetate or ethylene glycol monomethyl ether acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone; or alcohol solvents such as methanol, ethanol, isopropanol, n-butanol or isobutanol. Polymerization may be carried out by a conventional method using various organic solvents such as azo-based or peroxide-based and various commonly used polymerization initiators such as azo-based or peroxide-based.

In the polymerization, various mercaptans such as tert-dodecyl mercaptan, lauryl mercaptan, thioglycolic acid alkyl ester or β-mercaptopropionic acid, and polymerization using a molecular weight regulator such as α-methylstyrene dimer are performed. You can also.

Next, if only a typical example of a so-called aminosilane compound (B), which is a compound having one amino group and at least one hydrolyzable silyl group in one molecule, is to be mentioned. , 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane or (3-glycol And adducts of amines with compounds having both an epoxy group and a hydrolyzable silyl group, such as (sidoxypropyl) methyldiethoxysilane.

The amount of the aminosilane compound (B) used is as follows: the equivalent ratio of the carbonate group in the carbonate group-containing copolymer (A) to the amino group in the aminosilane compound (B): amino group / carbonate group = 0.01-2.
In the range of 00, preferably in the range of 0.1 to 1.5, and by setting the equivalent ratio in such a range, the coating film has good coating performance, and easily with moisture such as moisture in the air. The target resin which can be cured is obtained.

When the equivalent ratio exceeds 2, the cured coating film tends to have a problem of yellowing due to ultraviolet rays or heat,
In addition, chemical resistance, weather resistance, gloss and the like are likely to be adversely affected, while if it is less than 0.01, the curing itself is inevitably insufficient, so that the coating film performance becomes inferior. Are not preferred.

The objective is to heat-add the aminosilane compound (B) to the carbonate group-containing copolymer (A) under water-free conditions, respectively, as listed above.
A one-pack type curable resin having a hydrolyzable silyl group and excellent in low-temperature curability can be obtained.To prepare the target resin, various methods can be adopted. After the preparation of the group-containing copolymer (A), the aminosilane compound is subsequently prepared in the same reaction apparatus in the presence of the copolymer (A), for example, under an atmosphere of an inert gas such as nitrogen gas. (B) is diluted with an appropriate amount of an alcoholic solvent such as methanol, ethanol, propanol or butanol, if necessary, and gradually added dropwise while heating at a temperature of 40 to 110 ° C. In addition, a method in which the reaction is continued under stirring for several tens of minutes is simple and reliable.

The low-temperature curable resin thus obtained has a feature as a one-pack type curable resin which can be cured by moisture such as moisture in the air, because it contains a hydrolyzable silyl group itself. Yes, it can be used as a clear paint as it is, or it can be used as an enamel paint by mixing an appropriate pigment.

In addition, the target resin as an essential film-forming component,
Further, if necessary, by blending various film-forming resins compatible with the resin, such as acrylic resin, polyester resin, alkyd resin, polyamide resin, epoxy resin or urethane resin, as described above, air It has the characteristics of a one-pack type curable resin composition that can be cured with moisture such as moisture, and can be used as it is as a clear paint, or it can be enameled by mixing an appropriate pigment. It can also be used as a paint.

The amount of the optional film-forming resin to be used should be within the range not departing from the purpose and effect of the present invention, and at most, about 150 parts by weight based on 100 parts by weight of the low-temperature curable resin of the present invention. The range up to is appropriate.

Further, the low-temperature curable resin composition of the present invention may contain various conventional additives such as a leveling agent, an ultraviolet absorber or a pigment dispersant, if necessary.

In addition, it is of course possible to incorporate a hydrolyzable silyl group-containing compound such as tetramethoxysilane or tetraethoxysilane as a curing aid,
It goes without saying that a curing catalyst such as dibutyltin dilaurate can also be blended.

The resin composition of the present invention obtained in this manner is applied to an object to be coated according to a known and commonly used method such as a brush, a coater, a spray or a dip, and the object to be coated is paper or paper. Typical examples are processed products, wood materials or processed wood products, inorganic materials such as concrete or processed inorganic materials, metal materials or processed metal products, ceramics or processed products thereof, and various plastics or processed plastic products.

〔The invention's effect〕

Since the low-temperature curable resin composition of the present invention comprises a resin having a specific functional group called a hydrolyzable silyl group, the resin composition of the present invention itself has excellent low-temperature curability. Of course, on the other hand, the above-mentioned carbonate group-containing copolymer (A) and aminosilane compound (B), which are used for preparing the resin composition of the present invention, respectively, have an extremely good reaction. It gives a cured coating film having excellent performance from the point of having a property.

[Examples] Next, the present invention by reference examples, examples and comparative examples,
Although described more specifically, all parts and percentages are by weight unless otherwise specified below.

Reference Example 1 [Preparation Example of Carbonate Group-Containing Copolymer (A)] 700 parts of toluene was charged into a reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a cooling tube. To 300 ° C., and then 300 parts of styrene, 200 parts of methyl methacrylate, 95 parts of n-butyl acrylate, 5 parts of acrylic acid, 400 parts of 2,3-carbonate propyl methacrylate, azobis A mixture consisting of 10 parts of isobronitrile, 10 parts of tert-butyl peroxyoctoate, 5 parts of tert-butyl peroxybenzoate and 300 parts of toluene was added dropwise over 3 hours and then kept at the same temperature for 15 hours. The reaction was continued for a period of time.

As a result, a solution of a vinyl copolymer having a carbonate group (A) having a nonvolatile content of 50.2%, a Gardner viscosity at 25 ° C. (the same applies hereinafter) of UV, and a number average molecular weight of 13,700 was obtained. Hereinafter, this is referred to as a vinyl copolymer (A
Abbreviated as -1).

Reference Examples 2 to 5 (same as above) The same operation as in Reference Example 1 was repeated except that the monomer mixture was modified as shown in Table 1 to obtain various vinyl copolymers (A-2) to A solution of (A-5) was obtained.

The property values (nonvolatile content, viscosity and number average molecular weight) of each resin solution are shown in the same table.

Reference Examples 6 to 11 For each of the carbonate group-containing copolymers (A) obtained in Reference Examples 1 to 5, the type of aminosilane compound (B) as shown in Table 2 (1) and Using the amounts used, a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet was charged with each raw material, and nitrogen gas was introduced at a temperature of 100 ° C. The addition reaction was carried out for 30 minutes to obtain the desired one-pack low-temperature curable resin containing a hydrolyzable silyl group.

The addition reaction at this time was confirmed by tracking the rate of decrease in the characteristic absorption region of the carbonate group at 1817 cm ^-1 by infrared spectrum analysis.

Reference Examples 12 to 14 With respect to 100 parts by weight of each of the low-temperature curable resins (R-1) and (R-2) obtained in Reference Examples 6 and 7, 1
The low-temperature curable resin compositions of Reference Examples 12 and 13 were obtained by blending 00 parts by weight of “Acrydic A-135-50” (acrylic lacquer manufactured by Dainippon Ink and Chemicals, Inc.). For 100 weight of each low temperature curable resin, 100
Acrylic A-135-50 (acrylic lacquer manufactured by Dainippon Ink and Chemicals, Inc.) in parts by weight was blended to obtain a desired one-part low-temperature curable resin composition.

In Reference Example 14, "Acridic A-135-50" itself was used as a commercially available acrylic lacquer.

Examples 1 to 8 and Comparative Example 1 Tetraethoxysilane and di-n were added to the respective resins obtained in Reference Examples 6 to 11 at the compounding ratio (weight ratio) shown in Table 2 (2). -Butyl tin dioctoate was blended to obtain clear paints (P-1) to (P-6).

Further, with respect to the low-temperature curable resin compositions obtained in Reference Examples 12 and 13, tetraethoxysilane and di-n-butyltin were added at a compounding ratio (weight ratio) as shown in Table 2 (2). Dioctoate is blended and clear paint (P
-7) and (P-8) were obtained.

Further, as the paint of Comparative Example 1, "Acridic A
−135-50 ”was used.

Next, each paint was diluted to a spray viscosity with a diluting solvent.

First, each diluted paint is spray-coated on a polypropylene plate and left at 25 ° C to measure the gel fraction of the dried and cured coating film formed over time, thereby evaluating the low-temperature curability. Was performed. The results are summarized in Table 2 (2).

Subsequently, the above-mentioned various diluted paints were separately spray-coated on a glass plate and a Bondelite # 144-treated steel plate, and then left at room temperature (25 ° C.) for 7 days to be dried and hardened.

When the performance of each of the cured coating films thus obtained was evaluated, the results shown in Table 2 (3) were obtained.

The evaluation of “low-temperature curability” in Table 2 (2) is based on the weight of the coating film after immersion in acetone for 24 hours, followed by drying and weighing, that is, the weight loss due to immersion. The weight, that is, the value obtained by dividing by the original weight and multiplying by 100, is indicated by "%".

Further, the evaluation of “clearness” and “appearance” in Table 2 (3) was conducted by visually observing the coating film on the glass plate obtained by drying and curing at room temperature (25 ° C.) for 7 days. The "impact resistance" was measured using a DuPont impact tester with a 1 / 2-inch notch and 500
It is measured under the condition of a concave type with a g load, and
“Chemical resistance” is determined by visually observing the state of the coated surface after immersion for 24 hours.

In addition, various properties other than the above-mentioned "clearness" and "appearance", that is, "pencil hardness", "impact resistance",
Only the evaluation of the "yellowing degree" and the "chemical resistance" was performed on the coating film on the Bondelite # 144-treated steel sheet.

As is clear from Tables 2 (2) and (3), it is known that the low-temperature curable resin composition of the present invention gives an excellent cured product. In particular, the resin composition of the present invention has excellent low-temperature curability.

Claims (4)

(57) [Claims] (1) General formula 0.2 to 90% by weight of the polymerizable monomer (a-1)
And another monoethylenically unsaturated monomer (a-2) copolymerizable with this monomer (a-1), the total amount of all monomers being
A carbonate group-containing copolymer (A) obtained by copolymerization so as to be 100% by weight, and a compound (B) having both one amino group and at least one hydrolyzable silyl group in one molecule. ) As an essential film-forming component of a hydrolyzable silyl group-containing resin obtained by heating and subjecting to an addition reaction under moisture-free conditions. 2. The one-component low-temperature curable coating resin composition according to claim 1, wherein the condition without moisture is a nitrogen atmosphere. 3. The method according to claim 1, further comprising a curing catalyst.
The resin composition for a one-pack low-temperature-curable coating material according to item 1. 4. The resin composition for a one-component low-temperature curable coating according to claim 3, further comprising a curing aid.