JP2764995B2 - Low temperature curable resin composition - Google Patents

Description

The present invention relates to a novel and useful low-temperature curable resin composition.

More specifically, the present invention relates to a resin composition obtained by mixing a specific carbonate group-containing copolymer and a specific aminosilane compound as essential film-forming components, and in particular, has excellent low-temperature curability. .

[Conventional technology]

In recent years, acrylic lacquers and polyisocyanate-curable two-part urethane paints have been widely used as room-temperature drying paints having good weather resistance, but in the case of the former acrylic lacquer, they are low-priced and therefore economical. 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.

Accordingly, the present inventors have conducted intensive studies in view of the existence of various disadvantages in the conventional art as described above, and as a result, a specific carbonate group-containing copolymer and a specific aminosilane compound, the essential film forming properties The present invention has been completed by finding a resin composition having low-temperature curability, which is obtained by mixing the components, and having a balance of various properties, and which is particularly useful for coating materials.

Therefore, the object of the present invention is to provide a two-component low-temperature curable resin composition, particularly in a series of inventions for providing a coating resin composition having excellent low-temperature curability. And thereby seek to provide a novel curing system.

[Means to solve 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 is used as a base resin component, and one amino group and at least one hydrolyzable silyl group are combined in one molecule. It is intended to provide a two-component low-temperature curable resin composition comprising the compound (b-1) as a curing agent component, and in addition, a polymerizable monomer represented by the aforementioned general formula [I] 0.2 to 90% by weight of (a-1) and another monoethylenically unsaturated monomer (a-2) copolymerizable with this monomer (a-1), A carbonate group-containing copolymer (A) obtained by copolymerizing so that the total amount becomes 100% by weight, and the above-mentioned compound (a-1) as a curing agent component (B) of the copolymer (A) And / or at least two amino groups and at least one hydrolyzable silyl in one molecule Compounds having both bets (b-
2) is intended to provide a two-part low-temperature curable resin composition obtained by mixing at room temperature immediately before use as an essential film-forming component.

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 so-called carbonate group-containing polymerizable monomer (a-1) is used in an amount of 0.2 to 9% based on the total amount of all monomers.
A range of 0% by weight, preferably a range of 2 to 45% by weight 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) acrylic esters of various monohydric alcohols such as butyl acrylate, 2-ethylhexyl (meth) acrylate or lauryl (meth) acrylate; styrene, α-methylstyrene, p-te
Various aromatic vinyl compounds such as rt-butylstyrene, dimethylstyrene or vinyltoluene; (meth)
(Meth) acrylamides such as acrylamide, N-methylol (meth) acrylamide or butoxy (meth) acrylamide or various derivatives thereof; or various dialkylaminoalkyls such as dimethylaminoethyl (meth) acrylate or diethylaminoethyl (meth) acrylate Examples include (meth) acrylates and the like, and further include (meth) acrylonitrile, vinyl acetate, diethyl maleate, dibutyl maleate, dibutyl fumarate, diethyl itaconate and 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 known 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, the so-called aminosilane compound (B), which is the compound (b-1) and / or (b-2) having both an amino group and a hydrolyzable silyl group in one molecule, is described above. The carbonate group-containing polymer (A) is used as a curing agent component of a so-called base resin component.

As the aminosilane compound (B), when the components (A) and (B) are mixed,
First, before the low-temperature curable resin composition of the present invention is put to practical use, when both of these components (A) and (B) are mixed in advance by an ordinary method, in particular, one component per molecule is preferably used. 1
The compound (b-1) having both a primary amino group or a secondary amino group and at least one hydrolyzable silyl group is used. On the other hand, immediately before the low-temperature curable resin composition of the present invention is put into practical use When these components (A) and (B) are mixed at room temperature by a conventional method, in addition to the compound (b-1), at least two primary and / or two Compound (b-2) having both a primary amino group and at least one hydrolyzable silyl group is also used.

Among them, firstly, if only typical examples of the former compound (b-1) are exemplified, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, A compound having both an epoxy group and a hydrolyzable silyl group, such as 3-aminopropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane or (3-glycidoxypropyl) methyldiethoxysilane; And adducts with amines.

On the other hand, if only typical examples of the latter compound (b-2) are exemplified, N- (2-aminoethyl)
-3-aminopropyltrimethoxysilane or N-
Compounds containing an epoxy group and a hydrolyzable silyl group, such as (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, a copolymer of glycidyl (meth) acrylate and vinyltrimethoxysilane, and various amines And the like.

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.
It is appropriate to be within the range of 00, preferably within the range of 0.1 to 1.5, and by setting the equivalent ratio within such a range, a target resin composition having good coating film performance can be 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 low-temperature curable resin composition of the present invention thus obtained is
It can be used as a clear paint as it is,
Furthermore, by mixing an appropriate pigment, it can be used as an enamel paint.

The composition of the present invention may further contain, if necessary, various conventional additives such as a leveling agent, an ultraviolet absorber or a pigment dispersant.

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 composition of the present invention thus obtained 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. Representative examples include raw 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〕

The low-temperature-curable resin composition of the present invention is excellent in low-temperature curability, because the compound containing a hydrolyzable silyl group is used as a curing agent component as one component thereof. On the other hand, the copolymer (A) having a carbonate group as a base resin component has extremely good reactivity with an aminosilane compound as a curing agent component, and therefore, has a high performance in curing. It gives a coating film.

〔Example〕

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, and the mixture was placed in a nitrogen atmosphere The temperature was raised to 110 ° 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, and azobisisobromide A mixture consisting of 10 parts of nitrile, 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 at the same temperature for 15 hours. Hold and let the reaction proceed.

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.

Examples 1 to 9 and Comparative Example 1 Each solution of the carbonate group-containing copolymer (A) obtained in each Reference Example was used as a base resin component, and was blended as shown in Table 2 (1). A clear paint was obtained by ratio.

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

First, spray coating each diluted paint on a polypropylene plate, leave it at 25 ° C, and measure the gel fraction for each dry cured coating formed over time, thereby evaluating the low-temperature curability. Done. The results are as summarized in the table.

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 (2) were obtained.

In Comparative Example 1, "Acridic A-135-50" (a product of Dainippon Ink and Chemicals, Inc.) itself was used as a commercially available acrylic lacquer.

The evaluation of “low-temperature curability” in Table 2 (1) is based on the weight of the coating film after immersion in acetone for 24 hours and then 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 evaluations of "clearness" and "appearance" in Table 2 (2) were based on visual observation of 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 evident from the results in Table 2, the low-temperature curable resin composition of the present invention has an essential film-forming component in which the carbonate group-containing copolymer is compatible with an aminosilane compound as a curing agent. It is known that it gives excellent cured products. In particular, the composition of the present invention is excellent in low-temperature curability.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 33/14 C08F 220/26-220/30 C09D 133/14 C08F 20/26-20/30 C08F 120/26-120 / 30

Claims (2)

(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 the monomer (a-1) so that the total amount of all the monomers is 100% by weight. A carbonate group-containing copolymer (A) obtained by copolymerization is used as a base resin component, and one amino group and at least one amino group in one molecule.
(B-) having both hydrolyzable silyl groups
A two-component low-temperature-curable resin composition comprising 1) as a curing agent component. 2. The general formula 0.2 to 90% by weight of the polymerizable monomer (a-1)
And another monoethylenically unsaturated monomer (a-2) copolymerizable with the monomer (a-1) so that the total amount of all the monomers is 100% by weight. A compound (b-1) having both a carbonate group-containing copolymer (A) obtained by copolymerization, one amino group and at least one hydrolyzable silyl group in one molecule, and one compound in one molecule At least one compound (B) selected from the group consisting of compounds (b-2) having at least two amino groups and at least one hydrolyzable silyl group, immediately before use, A two-part low-temperature curable resin composition, which is mixed.