JP2608231B2 - Curable coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable coating composition which does not cause sagging.

[0002]

2. Description of the Related Art In recent years, in order to increase the durability of coating of marine structures, bridges, and the like, there has been a demand for an improvement in coating technology for spreading a coating film in a single coating process. In the conventional technology, as a means of giving thickness to the coating film, including vinyl resin paint, increasing the viscosity of the liquid component including the effect of the volatilization of the liquid component at the time of coating, and solid such as anhydrous silica fine powder. It has been proposed to improve the viscosity characteristics by adding a filler so as to prevent sagging.

[0003]

However, any of the above-mentioned prior arts has an insufficient sagging prevention effect, and it is difficult to obtain a coating film exceeding 1 mm in a single coating process. An object of the present invention is to solve the above-mentioned conventional problems and to provide a curable coating composition that does not cause sagging.

[0004]

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the present inventors have formulated a specific unsaturated alkyd into a vinyl resin paint, and added an organic peroxide and a polyvalent metal carboxylic acid. It has been found that the addition of a salt shows a specific increase in viscosity, and the present invention has been completed. That is, in the present invention, 10% or more of (1) hydroxyl terminal is represented by the following formula (I):

[0005]

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A unsaturated alkyd having a number average molecular weight of 5,000 or more occupied by the group of (2), (2) a vinyl compound, (3) an organic peroxide, and (4) a polyvalent metal carboxylate. It is intended to provide a curable coating composition comprising:

The present invention will be described in more detail below. (Unsaturated alkyd) In the unsaturated alkyd used in the present invention, 10% or more of the hydroxyl terminal is represented by the following formula (I):

[0008]

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Is an unsaturated alkyd having a number average molecular weight of 5,000 or more (hereinafter, referred to as a high molecular weight unsaturated alkyd).

The high-molecular-weight unsaturated alkyd is an unsaturated alkyd disclosed in Japanese Patent Application No. 3-62046 filed by the present applicant and not described in the literature, and its production method is described in detail in the specification. However, the outline is described below.

The high molecular weight unsaturated alkyd contains [A] (1) α, β-unsaturated polybasic acid or its acid anhydride as one component, and the ratio of its use is saturated or unsaturated. Not less than 10 mol% with respect to a total of 100 mol% with a basic acid (or an acid anhydride thereof),
And (2) a polyhydric alcohol having a boiling point of 300 ° C. or less at 760 mmHg,
A polyhydric alcohol containing 50 mol% or more with respect to 00 mol% is esterified and then subjected to a deglycolization reaction, which has a number average molecular weight of 5000 or more and has a terminal group substantially a hydroxyl group. It is obtained by reacting [B] trimellitic anhydride with a saturated alkyd in an amount of 10 mol% or more with respect to the hydroxyl group in the unsaturated alkyd of [A].

More specifically, first, in the step [A], (1) an α, β-unsaturated polybasic acid or its acid anhydride is contained as a component, and any saturated or unsaturated polybasic acid or its acid is added. (2) 100 parts by weight of a hydroxyl polyester having an acid value of 15 or less and a number average molecular weight of 500 or more obtained by esterification with a polyhydric alcohol, and 0.01 part by weight or more of an organic titanium compound catalyst. In addition, a glycol removal reaction is performed under a reduced pressure of 5 mmHg or less to synthesize an unsaturated alkyd having a number average molecular weight of 5000 or more. Subsequently, in step [B], the molecular terminal of the unsaturated alkyd is modified with trimellitic anhydride.

The raw materials of the polybasic acid used for synthesizing the high molecular weight unsaturated alkyd are not different from those of the conventional unsaturated alkyd production. Examples of the raw materials to be used include the following. (A) Examples of the α, β-unsaturated polybasic acid and its acid anhydride include maleic anhydride, fumaric acid, and itaconic acid. (B) Saturated or unsaturated polybasic acids (or acid anhydrides thereof) include those having a benzene nucleus, such as phthalic anhydride, isophthalic acid, terephthalic acid, and dimethyl ester; and aliphatic cyclic polybasic acids. Or as the acid anhydride thereof, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, het acid, and the like, further as an aliphatic dicarboxylic acid, Examples include succinic acid, adipic acid, azelaic acid, sebacic acid and the like. Examples of the halogen-containing acid include tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and the like, in addition to hettic acid.

Polyhydric alcohols having a boiling point of 300 ° C./760 mmHg or less include, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol 1,3, butanediol 1,3.
4, neopentyl glycol, 2-ethyl-2-methylpropanediol 1,3, 2-methyl-1,3-propanediol, pentanediol 1,5, hexanediol 1,
6. Further, as the alkylene monoepoxy compound,
Examples thereof include ethylene oxide, propylene oxide, epichlorohydrin, phenyl glycidyl ether and allyl glycidyl ether. The following types of polyhydric alcohols, which have high boiling points and are difficult to exchange with glycol, are 50 mol%
The following combinations can be used. That is, examples of the high boiling point polyhydric alcohol include hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin diallyl ether, and trimethylolpropane mono- or diallyl ether.

The synthesis of high molecular weight unsaturated alkyds is
The step [A] is carried out by esterification and deglycol reaction, and then the step [B] is carried out by carboxylation by addition of trimellitic anhydride. The esterification is carried out according to a conventional method at a temperature of 160 to 230 ° C. in an inert gas stream, and by substantially synthesizing a hydroxyl polyester with an acid value of 15 or less, preferably 10 or less.
As described above, the number average molecular weight at this time is 500 or more. The glycol removal reaction (transesterification reaction) is carried out in the presence of a catalyst under a high reduced pressure of 5 mmHg, preferably 1 mmHg or less. If the acid value exceeds 15 at this time, the deglycolization reaction will not be sufficiently performed, and as a result, it will be difficult to synthesize a desired high molecular weight unsaturated alkyd. As the catalyst, an organic compound of titanium can be used. Examples are tetrabutyl titanate, tetrapropyl titanate, and acetylacetonate of titanium. The amount used is 0.01 to 0.5 parts by weight, preferably 0.1 to 0.3 parts by weight, based on 100 parts by weight of the hydroxyl polyester.

The step (B) is carried out by adding a predetermined amount of trimellitic anhydride and treating the mixture at about 150 to 250 ° C. under a reduced pressure of 5 mmHg or less under a flow condition of a high molecular weight unsaturated alkyd. At this time, the proportion of the carboxyl group is 10 mol% or more in terms of the total mol% of the terminal groups. Below this, the substantial meaning of introducing a carboxyl group is poor. The most suitable range is, of course, 30 mol% or more and 90 mol% or less, although it depends on the application. Of course, the number of terminal groups per unit weight differs depending on the molecular weight, the molecular weight in the present invention, GPC (column Showdex, No.KF-805 type, 4 × 10 ⁶ in exclusion limit molecular weight polystyrene, Showa (Manufactured by Denko Corporation).

The high molecular weight unsaturated alkyd is preferably used in an amount of 2 to 70% by weight, preferably 3 to 50% by weight, based on the vinyl compound. If it is less than 2% by weight, the action of the polyvalent metal carboxylate is weakened, and if it is more than 70% by weight, the viscosity of the vinyl compound becomes excessively large, which is not preferable for use as a coating material. The preferred molecular weight is 5,000 to 15,000.

(Vinyl Compound) As the vinyl compound used in the present invention, various compounds can be used, and examples thereof include styrene, divinylbenzene, methyl methacrylate, N-vinylpyridine, higher alcohols and acrylic acid or methacrylic acid. Unsaturated esters obtained from acids,
Unsaturated esters obtained from polyhydric alcohols and acrylic acid or methacrylic acid, unsaturated urethanes obtained from alcohols including polyhydric alcohols as raw materials,
Examples thereof include radically polymerizable compounds such as unsaturated epoxy esters and unsaturated alkyds obtained from an epoxy resin and acrylic acid or methacrylic acid.
In addition, the higher alcohol mentioned here also means a monohydroxy compound having a molecular weight of 100 to 500 including cellosolves, for example. Further, the polyhydric alcohol referred to here means a molecular weight of 100 to 100 such as polypropylene glycol.
It also means 5000 divalent hydroxy compounds. The vinyl resin can be produced by appropriately selecting these compounds.

(Organic peroxide) Examples of the organic peroxide which can be used in the composition of the present invention include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, cumene hydroperoxide, p- Hydroperoxides such as Menthane Hydroperoxide, Benzoyl Peroxide,
Mention may be made of diacyl peroxides such as 2,4-dichlorobenzoyl peroxide. When using diacyl peroxide, it is preferable to use a decomposition accelerator such as dimethylaniline in combination. When another organic peroxide is used, it is preferable to use a cobalt salt in combination as a decomposition accelerator to act as a curing agent at around normal temperature. The amount of the organic peroxide to be used is about 0.5 to 5% by weight based on the total weight of the composition.

(Polyvalent metal carboxylate) The polyvalent metal carboxylate used in the present invention is used as an organic peroxide decomposition accelerator or a thickener. For example,
Examples thereof include zinc, magnesium, calcium, cobalt, zirconium, lead, copper, tin and nickel salts of naphthenic acid and octylic acid. Among them, a preferred polyvalent metal carboxylate is a cobalt salt of octylic acid. Among the polyvalent metal carboxylate salts, the cobalt salt is effective because it functions as a decomposition accelerator for many peroxides added for curing the vinyl resin at room temperature. In addition, the polyvalent metal carboxylate can be used in various combinations. The amount of the polyvalent metal carboxylate to be used is about 0.01% to 0.2% by weight as a metal based on the weight of the whole composition. The polyvalent metal carboxylate can be previously mixed in the coating composition. Further, it can be added at the time of forming the coating film.

Furthermore, various fillers can be added to the composition of the present invention, if necessary. For example, talc,
Titania, zirconia, glass powder, glass flakes, mica, calcium carbonate, lead sulfate, beryllium sulfate, etc. are used.
The following volume ratio is preferable.

When the curable coating composition of the present invention is used as a coating material, first, a high molecular weight unsaturated alkyd and a vinyl compound are blended, and then an organic peroxide and a polyvalent metal carboxylate are added. At this time, as a means for incorporating the polyvalent metal carboxylate into the composition, the polyvalent metal carboxylate may be previously mixed with the composition, but the polyvalent metal carboxylate may be added to the spray liquid of the paint. The two-liquid spray method, which is carried out while mixing the above spray liquid, is an excellent means from the viewpoint of uniformity of coating film and speed of work. When the above components are mixed in the respective usage ratios, they can be used as they are as a coating material which does not cause sagging.

[0023]

The present invention will be described below with reference to examples. In the examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 (Synthesis of High Molecular Weight Unsaturated Alkyd) 2-Methyl-1,
11.5 mol of 3-propanediol and 8 mol of dimethyl terephthalate were added in the presence of 2 g of zinc acetate to 185-1.
After heating at 95 ° C. to distill off methanol, 2 mol of fumaric acid was added to proceed esterification to an acid value of 7.9. The number average molecular weight was about 1700. 3.2 g of tetraisopropyl titanate and 0.6 of hydroquinone
g was added, and the pressure was finally reduced to 0.8 mmHg at 205 to 210 ° C. to carry out the deglycol reaction. It was determined that the product had substantially no acid value and the terminal group was a hydroxyl group. 90 g of trimellitic anhydride was added to this,
The mixture was heated and stirred at 205 to 210 ° C. for 30 minutes to obtain a high molecular weight unsaturated alkyd. Its number average molecular weight is 11,
It was 000.

Subsequently, paint formulations shown in Table 1 below were prepared,
Further, 1 part of methyl ethyl ketone peroxide and 0.5 part of cobalt octylate solution (containing 8% by weight of cobalt) were sequentially added.

[0026]

[Table 1]

Upon mixing with the cobalt octylate liquor, the coating composition changed from a fluid liquid to a less fluid putty. When applied to a vertical surface with a rubber spatula to a thickness of 2 to 3 mm, the coating was cured without sagging.

Example 2 11.5 mol of 2 -methyl-1,3-propanediol,
After 8 mol of dimethyl terephthalate was heated at 185 to 195 ° C. in the presence of 2 g of zinc acetate to distill off methanol, 2 mol of fumaric acid was added and esterification was allowed to proceed to an acid value of 8.3. The number average molecular weight was about 1500. 3.2 g of tetraisopropyl titanate and 0.6 g of hydroquinone were added thereto, and the pressure was reduced to a final value of 0.8 mmHg at 205 to 210 ° C. to carry out a deglycol-reaction. This was determined to have substantially no acid value and the terminal group to be a hydroxyl group. To this, 115 g of trimellitic anhydride was added, and the mixture was heated and stirred at 205 to 210 ° C. for 30 minutes to obtain a high molecular weight unsaturated alkyd. Its number average molecular weight was 8,300.

Subsequently, paint formulations shown in Table 2 below were prepared,
Furthermore, 1 part of methyl ethyl ketone peroxide and 0.3 part of a cobalt octylate solution (containing 8% by weight of cobalt) were sequentially added.

[0030]

[Table 2]

Upon mixing with the cobalt octylate liquor, the coating composition changed from a fluid liquid to a less fluid putty. When applied to a vertical surface with a rubber spatula to a thickness of 2 to 3 mm, the coating was cured without sagging.

Example 3 The formulations shown in Table 3 below were prepared. The high molecular weight unsaturated alkyd used was the same as that produced in Example 2. In addition, cumene hydroperoxide 1.
5 parts were added. Spray-mixing of the two liquids at a ratio of 2 parts by weight of cobalt octylate liquid (containing 4% by weight of cobalt) to 100 parts by weight of this coating liquid gave 2-3
mm spray painted. Cured without sagging.

[0033]

[Table 3]

[0034]

EFFECT OF THE INVENTION The present invention provides a curable coating composition free from sagging.

Claims (1)

(57) [Claims] (1) 10% or more of a hydroxyl terminal is
The following formula (I) (2) a vinyl compound, (3) an organic peroxide, and (4) a polyvalent metal carboxylate. Composition for curable paint.