JPH03128982A - Coating resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in the balance between the dryability and the appearance by using a specified acrylic polyol in a two-pack acrylic urethane coating resin composition consisting of a principal component composed mainly of an acrylic polyol and a curing agent comprising a polyisocyanate. CONSTITUTION:A two-pack acrylic urethane coating resin composition consisting of a principal component composed mainly of an acrylic polyol and a curing agent comprising a polyisocyanate which are mixed before use, wherein an acrylic polyol mixture containing a low molecular acrylic polyol (A) (e.g. a copolymer of methyl, n-butyl or hydroxyethyl methacrylate, hydroxyethyl acrylate, styrene, or methacrylic acid) having a number-average molecular weight of 7, 000 or lower and a high-molecular acrylic polyol (B) (e.g. a copolymer obtained from the same raw material as that for the copolymer mentioned above) having a number-average molecular weight of 10,000 or higher at a weight ratio of A to B of 00.5 to 9 is used as the acrylic polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a resin composition for a two-component acrylic urethane paint that has a good balance between drying properties and appearance.

[Conventional technology]

In two-component acrylic urethane paints, drying performance can be improved by blending a hard resin such as nitrified cotton or cellulose acetate butyrate (CAB) with the acrylic polyol as the main ingredient, or by increasing the molecular weight of the polyol. .

However, the viscosity of the paint increases and the flowability of the paint film decreases, resulting in poor appearance and poor workability.

Furthermore, nitrified cotton, CAB, and the like have limitations in the composition of acrylic polyols.

In order to obtain a paint with a good appearance, - For boat fishing, it is possible to use a high solid type paint film with good flowability, such as a low molecular weight acrylic polyol.

However, when the molecular weight of the acrylic polyol becomes low, the drying properties tend to decrease and performance such as moisture resistance, chemical resistance, and weather resistance tends to decrease.

Furthermore, due to its low molecular weight, it had the disadvantage that the paint easily dripped when applied.

[Problem to be solved by the invention]

As described above, there is a contradictory tendency that increasing the drying property reduces the appearance, and increasing the appearance reduces the drying property.Therefore, there was a desire for a resin composition for paints with a balance between drying property and appearance. .

[Means to solve the problem]

In order to solve the above problems, the present invention was developed as a result of intensive studies, and by co-curing a high molecular weight acrylic polyol with a low molecular weight acrylic polyol of the acrylic polyol that is the main component in a two-component acrylic urethane paint,
We were able to develop a two-component acrylic urethane paint resin composition that has a good balance between drying properties and appearance, and finally completed the present invention.

That is, the present invention provides a resin composition for a two-component acrylic urethane paint in which a main component mainly composed of an acrylic polyol and a curing agent which is a polyisocyanate are mixed at the time of use, wherein the acrylic polyol is (1) ) contains a low molecular weight acrylic polyol (A) with a number average molecular weight of 7,000 or less and (2) an acrylic high molecular weight polyol (B) with a number average molecular weight of 10,000 or more; (3) a mixing ratio of A and B; An object of the present invention is to provide a resin composition for a two-component acrylic urethane paint in which the weight ratio is in the range of 0.5≦(A)/(B)≦9.

The low molecular weight acrylic polyol (A) used in the present invention has a number average molecular weight of 7.000 or less, preferably 4.
,000 to 7,000 is appropriate.

The number average molecular weight of the low molecular weight acrylic polyol is 4.00.
If it is less than 0, sufficient drying properties cannot be obtained, and if it exceeds 7.000, the appearance tends to deteriorate.

Further, the high molecular weight acrylic polyol (B) has a number average molecular weight of 10,000 or more, preferably 12.0
00 to 20,000 is appropriate.

The number average molecular weight of high molecular weight acrylic polyol is 12.0
If it is less than 20.00, sufficient drying properties cannot be obtained;
If it exceeds 0, the appearance deteriorates, which is not preferable.

The mixing ratio of low molecular weight acrylic polyol (A) and high molecular weight acrylic polyol (B) is 0.5≦(A
)/(B)≦9 is appropriate.

When (A)/(B) exceeds 9, the drying property becomes extremely slow, and when it is less than 0.5, the appearance deteriorates.

The acrylic polyol used in the present invention includes -i
A copolymer synthesized by solution mixing using radical polymerization is suitable, and can be obtained, for example, by copolymerizing a hydroxyl group-containing vinyl monomer and an acrylic monomer.

Here, the hydroxyl group-containing monomer includes, for example, a monoester of acrylic acid or methacrylic acid and a glycol having 2 to 10 carbon atoms, and specifically, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl Examples include methacrylate.

Examples of acrylic monomers include alkyl (carbon numbers 1 to 24) esters of acrylic acid or methacrylic acid, and also carboxy group-containing vinyl monomers such as acrylic acid and methacrylic acid, amide vinyl monomers, and glycidyl group m Vinyl monomers, styrene and its derivatives, acrylonitrile, vinyltoluene, vinyl chloride, vinyl acetate, etc. can also be used in combination. These may be used alone or in combination of two or more.

In the present invention, the above acrylic polyol alone is preferred, but other components such as polyester polyol and epoxy polyol can also be used in combination.

As the acrylic polyol used in the present invention, it is preferable to use one with a hydroxyl group of 10 to 150 KOI (■/g). If the hydroxyl group is 10 KOH■/g, water resistance etc. will decrease, and 150 KOH■/g If it exceeds the limit, the adhesion will decrease.

A more preferable acrylic polyol has 3 hydroxyl groups.
It is about 0 to 80 KOI (■/g).

As the polyisocyanate used as a curing agent in the present invention, any commonly used and known polyisocyanate can be used.

Examples of these polyisocyanates include hexamethylene diisocyanate (HMDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), 1,4-cyclohexane diisocyanate, and dicyclohexylmethane diisocyanate (HMD).
I), bis(isocyanatomethyl)cyclohexane (H
Aliphatic or alicyclic diisocyanates such as XDT), or tolylene diisocyanate (TDI), diphenylmethane isocyanate (MDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), diphenyl ether diisocyanate, tolidine diisocyanate, dianisidine Aromatic diisocyanates such as diisocyanate and naphthalene diisocyanate (MDI), or aromatic substances such as crude tolylene diisocyanate (crude↑DI), polymethylene polyphenylene polyisocyanate (polymeric MDI), triphenylmethane triisocyanate, and tris(phenylisocyanate) thiophosphate. Group polyisocyanates, and isocyanate-modified products such as isocyanurate-modified products, biuret-modified products, and carbodiimide-modified products of the above-mentioned diisocyanate monomers can be used.

The blending ratio of polyol and polyisocyanate can be variously selected depending on the purpose, but in the present invention, isocyanate groups (N
It is preferable that the equivalent ratio (NCO10H) of CO) and hydroxyl group (OH) be in the range of 0.7 to 1.5.

It is preferable that the composition of the present invention further contains a catalyst such as a tin compound.

As the above catalyst, those commonly used in urethanization reactions can be used, but tin-based compounds are most preferred.

Examples of these compounds include dibutyltin laurate, diptyltin di(2-ethylhexoate), tin chloride, and tetra-n-butyltin. Among these, dibutyltin laurate is particularly preferred.

The blending amount of the above catalyst is 0.00 parts per 100 parts by weight of the acrylic polyol. Approximately 1 to 0.5 parts by weight of O is suitable.

In the present invention, pigments such as coloring pigments, extender pigments, aluminum flakes, etc., leveling agents, anti-settling agents, etc., which are usually blended in this type of coating composition, can also be blended as necessary.

Further, as the organic solvent, for example, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and ester solvents such as ethyl acetate and cellosolve acetate can be used.

When using the two-component acrylic urethane paint resin composition of the present invention, for example, the coating viscosity (Ford cup #420°C) is 10 to 20 seconds, preferably 13 to 17 seconds.
The cured coating film is adjusted to 10 to 40 seconds and then applied according to conventionally known painting methods such as air spray or airless spray.
It is best to paint so that the thickness is around μ.

It can also be applied to coating systems such as paper cure, paper injection cure (VIC), etc., in which the coating system is brought into contact with tertiary amine vapor after or during coating.

According to the present invention, there is no need to blend a hard resin such as nitrified cotton or cellulose acetate butyrate (CAB) into a base agent mainly composed of acrylic polyol, as in the past, so the viscosity of the paint is relatively low. Therefore, it is possible to provide a resin composition for a two-component urethane type acrylic urethane paint, which has an extremely excellent appearance due to improved flowability of the coating film, and has excellent drying properties.

〔Example〕

EXAMPLES Hereinafter, in order to explain the present invention more specifically, Examples and Comparative Examples will be given and explained, but the present invention is not limited to these Examples.

Reference Example 1 After purging nitrogen into a four-bottle flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, 100 parts of Kijirole was charged into the flask and the temperature was raised to 130°C. . Next, the raw materials shown in Table 1 were added dropwise over 5.5 hours, and after 1.5 hours, the mixture was held at 110°C for 2 hours to obtain an acrylic polyol with a solid content of about 50%.

Reference Example 2 Acrylic Polyol b No. 0 After purging nitrogen into a four-bottle flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 70 parts of Kijirole was charged into the flask and the temperature was raised to 100°C. . Next, the raw materials shown in Table 1 were added dropwise over 5.5 hours.
After the dropwise addition and holding at the temperature for an additional 5 hours, 30 parts of Kijirole was added to obtain an acrylic polyol with a solid content of approximately 50%.

Examples 1-4 Pacco S 1st Ken The base coat paint was formulated as follows.

Synthesized acrylic resin (solid content 50χ) 70 parts Titanium oxide CR-90 (manufactured by Ishihara Sangyo Co., Ltd.) 46.5 parts Thinner (xylene: toluene: butyl acetate: methyl isobutyl ketone -2:1:1:1) 30 parts Cash register Gotsukusu RL-4 (level linking agent; manufactured by Mitsui Toatsu Chemical Co., Ltd.) 0.07 parts VIC5054 (manufactured by Ashland Kegokal Co., Ltd.) 0.0
7 parts The pigment was dispersed in the above formulation for 1 hour using a paint shaker.

As a curing agent, Olestar NP100O (manufactured by Mitsui Toatsu Chemical Co., Ltd.) was blended so that the equivalent ratio was NC0101-I-1, and further diluted with the above thinner.
The viscosity was adjusted to 14 seconds/20°C to obtain a hair coat paint.

Table 2 shows blending examples of acrylic polyol resins.

Apply this paint to the 5PCC-5 [l #144 treated plate, VI
It was sprayed using a C system to a film thickness of 30 μm.

The results are shown in Table-3.

Comparative examples 1 to 4 A hair coat paint was obtained in exactly the same manner as in the example.

Table 2 shows blending examples of acrylic polyol resins.

This paint was applied to 5PCC-3B#144 as in the example.
The treated plate was sprayed with a VTG system to a film thickness of 30 μm.

2 Display results Shown in 3.

Performance evaluation was performed as follows.

1) Visual appearance Those with excellent coating film appearance were rated ◎, and those with poor coating film appearance were rated ×.

2) Gloss The gloss was measured using a gloss meter at 60°C gloss.

3) Drying time to the touch and complete curing time (no marks left when rubbed with fingers) 4) Adhesion JIS K5400 cellophane tape test 3 Table 5 16 [Effects of the invention] Two-component acrylic according to the present invention Resin bottoms for urethane paints are well-balanced and have excellent drying properties and appearance, whereas conventional resin bottoms for two-component acrylic urethane paints (comparative example 4)
Table 3 shows that although drying property is fast, the appearance deteriorates, and the two-component acrylic urethane paint resin composition (Comparative Example 3), which has low molecular weight acrylic polyol as the main ingredient, has excellent appearance but poor drying property. it is obvious.

Claims (1)

[Scope of Claims] 1. A two-component acrylic urethane paint resin composition in which a main component containing an acrylic polyol and a curing agent which is a polyisocyanate are mixed at the time of use,
The acrylic polyol contains (1) a low molecular weight acrylic polyol (A) having a number average molecular weight of 7,000 or less and (2) a high molecular weight acrylic polyol (B) having a number average molecular weight of 10,000 or more; ) A resin composition for a two-component acrylic urethane paint, characterized in that the mixing ratio of A and B is in the range of 0.5≦(A)/(B)≦9 in terms of weight ratio.