JPS60243164A - Resin composition of coating - Google Patents

Abstract

PURPOSE:The titled composition that is obtained by using a vinyl copolymer modified with a specific drying oil fatty acid and a polyfunctional acrylic monomer at a specific ratio, thus being suitable for use as a finish coating for industrial machines, because it has high oil resistance and high adhesion to metal. CONSTITUTION:The objective composition is obtained by adding (A) 30-5wt%, preferably 20-10wt% of a polyfunctional acrylic monomer such as ethylene diaacrylate to (B) 70-95wt%, preferably 80-90wt% of fatty acid-modified vinyl copolymer which is prepared by addition reaction of (i) 10-60pts.wt., preferably 20-50pts.wt. of a drying oil fatty acid with an iodine value of 100-200 such as dehydrogenated castor oil, to (ii) 100pts.wt. of a vinyl copolymer from 5-50wt% of a vinyl monomer bearing hydroxyls and/or glycidyl group such as glycidyl acrylate and an alpha,beta-ethylenically unsaturated monomer copolymerizable with the above monomer such as methyl acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and useful resin composition for coatings,
More specifically, it relates to a resin composition that contains a specific drying oil-fatty acid-modified vinyl copolymer and a polyfunctional acrylic monomer as essential components, and has particularly excellent oil resistance and adhesion to metals. .

Traditionally, medium-oil or long-oil alkyd resins and acrylic lacquers, which are cured by the addition of a metal dryer, have been mainly used as top coats for industrial machinery, agricultural equipment, large vehicles, land structures, etc.

However, alkyd resins generally have excellent pigment dispersibility and coating workability, and the resulting cured coating film also has excellent flexibility and adhesion to metal substrates. In particular, −
One example is that it is extremely resistant to cracking in cold and hot cyclic fatigue tests in the temperature range of 60°C to +80°C, and these properties mean that, for example, industrial machinery and large vehicles will not cause paint film cracking in cold regions. This is an extremely important factor.

As described above, although alkyd resins have excellent properties, they have the disadvantage of poor drying properties.

On the other hand, the acrylic resins used in acrylic lacquers generally have a high molecular weight, and therefore acrylic lacquers obtained from such acrylic resins or in combination with fibrous cords such as nitrified cotton or cellulose acetate butyrate are very difficult to obtain. Although it dries quickly, it is inferior to the above-mentioned alkyd resins in terms of paint workability and texture, and is hard and brittle, so it has the disadvantage of being easily broken in cold regions.

Therefore, the present inventors conducted extensive research to develop a well-balanced resin that combines the quick-drying properties of acrylic lacquers with the gloss, texture, and physical properties of the coating that are inherent to alkyd resins. As a result, it was confirmed that a mixture of a drying oil fatty acid modified □ vinyl copolymer and a polyfunctional acrylic monomer is suitable for these purposes.

By the way, such a drying oil fatty acid modified vinyl copolymer itself has been known for a long time, for example, as disclosed in British Patent No. 79.
No. 3776 describes a copolymer of glycidyl methacrylate with a drying oil fatty acid added to it, and JP-A-53-99231 discloses a copolymer of glycidyl methacrylate in which residual hydroxyl groups are added in order to improve pigment dispersibility and physical properties. It has also been reported that a method of adding carboxylic anhydride has been adopted.

And this kind of drying oil fatty acid modified vinyl copolymer is
For example, it can also be obtained by directly esterifying a hydroxyl group-containing vinyl copolymer with a drying oil fatty acid, but such a method has also been known for a long time.・A method of esterifying a β-hydroxyethyl acrylate copolymer with a drying oil fatty acid has been reported, and recently, the glass transition temperature was determined using the same kind of drying oil fatty acid modified vinyl copolymer as mentioned above. (T
A high solids composition in which g) is 20° C. or higher is also reported in JP-A-56-18659.

However, this type of drying oil-fatty acid modified vinyl copolymer is independent of whether the backbone polymer has a hydroxyl group or a glycidyl group; Products esterified with drying oil fatty acids, and products with dicarboxylic anhydride added to the remaining hydroxyl groups, generally have a glossy and fleshy feel, and are not well-balanced in terms of quick-drying properties. However, the adhesion to metal substrates is still insufficient and there is room for improvement.

However, as mentioned above, the present inventors have discovered that a resin composition containing this type of drying oil fatty acid-modified vinyl copolymer and a polyfunctional acrylic monomer as essential components can be applied to metal substrates. The present invention was completed based on the discovery that it has excellent oil resistance as well as adhesion.

That is, the present invention contains hydroxyl groups and/or
Alternatively, 5 to 50% by weight of a vinyl monomer having a glycidyl group and 5 to 50% by weight of another α,β-ethylenically inert saturated monomer copolymerizable with the vinyl monomer. For 100 parts by weight of the vinyl copolymer (a-1) obtained by polymerization, the drying oil fatty acid (a-2) having an iodine value of 100 to 200 is added in a proportion of 10 to 60 parts by weight. Fatty acid modified vinyl copolymer (A) obtained by addition reaction
70 to 95% by weight of polyfunctional acrylic monomer (B'
) as an essential ingredient.
The present invention provides a resin composition for paint that can be cured at a low temperature of 80° C. or lower and has particularly excellent oil resistance and adhesion to metal materials.

Here, the backbone polymer of the fatty acid-modified vinyl copolymer mentioned above refers to a vinyl monomer having a hydroxyl group and/or a glycidyl group, that is, a group consisting of a hydroxyl group-containing vinyl monomer and a glycidyl group-containing vinyl monomer. A specific ratio of at least one selected specific functional group-containing vinyl monomer and an α,β-ethylenically unsaturated monomer copolymerizable with these specific functional group-containing vinyl monomers. It refers to a copolymer, among which the representative hydroxyl group-containing vinyl monomers include β
-Hydroxyalkyl acrylates or hydroxyalkyl methacrylates such as hydroxyethyl (meth)acrylate, β-hydroxypropyl (meth)acrylate or γ-hydroxybutyl (meth)acrylate, and are also representative of the glycidyl group-containing vinyl monomers mentioned above. Typical examples include glycidyl (meth)acrylate and β-methylglycidyl (meth)acrylate, and these vinyl monomers containing both functional groups can be used alone or in combination.

Although allyl glycidyl ether is not included in vinyl monomers, it can be treated as a co-effective substance of such vinyl monomers in the present invention.

On the other hand, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, etc. ) acrylate, alkyl (meth)acrylates such as butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate or stearyl (meth)acrylate; methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate or Ether esters, such as tetrahydrofurfuryl (meth)acrylate; Dialkyl or monoalkyl esters of basic acids; unsaturated dibasic acids or their anhydrides such as maleic anhydride, fumaric acid or itaconic acid; unsaturated-basic acids such as (meth)acrylic acid or crotonic acid; or Styrene, vinyltoluene, vinyl acetate, vinyl propionate, (meth)acrylonitrile, hinyl chloride,
Examples include ethylene, (meth)acrylamide, vinylpyrrolitone or cyclohexyl methacrylate.

However, among these acidic monomers, although there is no problem when copolymerizing with the above-mentioned hydroxyl group-containing vinyl monomer, when copolymerizing with the glycidyl group-containing vinyl monomer, Since there is a possibility that a reaction between glycidyl groups and carboxyl groups occurs during copolymerization, resulting in gelation, care must be taken in selecting monomers and polymerization conditions.

The amount of the vinyl monomer having a hydroxyl group and/or glycidyl group used is 5 to 5 in the total copolymer component.
A suitable range is 0% by weight, preferably 20 to 40% by weight.

Of course, the optimal ratio of these vinyl monomers containing both functional groups varies depending on how each resin is designed depending on the use of the composition of the present invention, but if it is less than about 5% by weight, the drying property The addition rate of oil fatty acids is low, making it difficult to obtain oxidative polymerizability, and conversely, if it exceeds 50% by weight, the addition rate becomes high, resulting in a decrease in drying properties, so in either case. I also don't like it.

The vinyl copolymer (a
-1), in the presence of a known and commonly used radical polymerization catalyst in an aromatic, ketone, or ester solvent, various functional group-containing vinyl monomers as listed above are used. The compound and other α,β-ethylenically unsaturated monomers may be copolymerized by a conventional method.

In this case, when a hydroxyl group-containing vinyl monomer is used as the functional group-containing vinyl monomer, an esterification process accompanied by a dehydration reaction with a drying oil fatty acid such as a backbone is carried out subsequent to this copolymerization reaction. Therefore, it is desirable to use toluene or xylene as the polymerization solvent.

Furthermore, the final resin solution may be one in which part or all of the polymerization solvent is replaced with an aliphatic or naphthenic solvent.

In particular, when recoatability is important, replace with turpentine, Swasol 310J (an aliphatic hydrocarbon mixture manufactured by Maruzen Sekiyu S), or even Isopar (an isoparaffin mixture solvent manufactured by Exxon in the United States). It is preferable.

Further, typical radical polymerization catalysts used in the copolymerization reaction include organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, tert-butyl perbenzoate, di-tert-butyl peroxide, and cumene hydroperoxide. and azo compounds such as azobisisobutyronitrile.

Furthermore, a chain transfer agent such as lauryl mercaptan or thioglycolic acid ester can be used simultaneously with these various radical polymerization catalysts, if necessary.

In addition, the polymerization conditions and method are not particularly limited, but generally it is appropriate to carry out the polymerization at a temperature of 80 to 140°C under normal pressure. It is appropriate to carry out under pressure.

The drying oil fatty acid (a-2) used in the esterification of the vinyl copolymer (a-1) thus obtained is suitably one with an iodine value within the range of 100 to 200; Typical drying oil fatty acids (a-2) include fatty acids from natural oils such as rice bran oil, tall oil, soybean oil, cottonseed oil, safflower oil, dehydrated castor oil, linseed oil, and tung oil; There are synthetic oils and fatty acids such as Percules Co., Ltd. products), but these may be used alone or in combination, and the amount used is 10 to 6 parts by weight per 100 parts by weight of the vinyl copolymer (a-1).
A suitable amount is 0 parts by weight, preferably 20 to 50 parts by weight.

If the amount used is less than 10@777 parts, the desired oxidative polymerizability cannot be obtained, and on the other hand, if it exceeds 60 parts by weight, the amount of drying oil fatty acid added is too large. Both are unfavorable because they reduce drying properties.

The conditions for the esterification with the fatty acid, that is, the addition reaction between the vinyl copolymer (a-1) and the drying oil fatty acid (a-2), are based on the functional groups in the vinyl copolymer (a-1>) used. It varies depending on the type, but in the case of a copolymer containing hydroxyl groups, the copolymer is obtained by solution polymerization, which is then heated while removing the solvent, and finally reaches 180%
It is best to react at a temperature of ~240°C until the reaction rate of hydroxyl groups reaches 90% or more, and the addition reaction (
Dehydration (esterification) can be monitored by measuring the acid value of free fatty acids.

After this addition reaction (dehydration esterification) is completed, the modified copolymer is diluted with a solvent such as toluene, xylene, turpentine, "Swazol" or "Isopar" alone or in a mixture, as described above. .

Next, in the case of a copolymer containing a glycidyl group, since it can be easily subjected to an addition reaction (ring-opening esterification) in a solution state, that is, in a copolymer solution after solution polymerization, The drying oil fatty acid (a-2) was added to the solution polymerized copolymer solution, and 11
The reaction is preferably carried out at a temperature of 0 to 140°C, and the end point of the addition reaction (ring-opening esterification) can be monitored by measuring the acid value of the free fatty acid in the same manner as in the case of dehydration esterification as described above. Bye.

Such addition reactions, whether dehydration esterification or ring-opening esterification, may be carried out using a known and commonly used esterification catalyst, but it is better to carry out the modification without a catalyst. This is advantageous because there is no coloration of the copolymer and no deterioration in the performance of the resulting coating film.

During such an addition reaction, the drying oil fatty acid (a-2)
is usually 0.0 for each hydroxyl or glycidyl group.
It is preferable to use it in a proportion of 8 to 1.0 mol, and it is desirable to reduce the amount of unreacted fatty acid as much as possible.

Next, the polyfunctional acrylic monomer (B), which can also be called the second essential component constituting the composition of the present invention, is a so-called oligoacrylate or oligomethacrylate.
It refers to an oligomer having a (meth)acryloyloxy group at the end or side chain of the molecule, and acts as a crosslinking agent component for crosslinking and curing the fatty acid-modified vinyl copolymer (A) as described above.

Among them, typical oligoacrylates include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, 1,3-
Butylene glycol, 1,4-butylene glyconyl, 1
, 6-hexanediol, neopentyl glycol, bisoxyethylene bisphenol A or bisoxypropylene bisphenol A di(meth)acrylate; trimethylolethane, trimethylolpropane, glycerin also available; tris(2-hydroxyethyl isocyanurate) di- or tri(meth)acrylates; tri-, tetra-, penta- or hexa(meth)acrylates of pentaerythritol or dipentaerythritol; one example is benku or hexa(meth)acrylate of hexahydroxymethylmelamine;

The amount of the polyfunctional acrylic monomer (B) used is 70 to 70% of the fatty acid-modified vinyl copolymer (A).
30-5% by weight relative to 95% by weight, preferably (A)
This is in a proportion of 20 to 10% by weight relative to 80 to 90% by weight of the components.

As this usage ratio, the presence rate in the target composition is 5.
If it is less than 30% by weight, sufficient crosslinking will not be achieved, and if it exceeds 30% by weight, the monomer (
B) remains unreacted, or the monomer (
Both are unfavorable because a coating film with sufficient performance cannot be obtained due to the formation of the homopolymer B).

The resin composition for coating of the present invention thus obtained can be blended with a curing accelerator, or the accelerator and peroxides, and by doing so, the composition of the present invention can be cured. .

Here, typical curing accelerators include one or a mixture of two or more metal soaps such as cobalt, lead, calcium or manganese salts of naphthenic acid.

Furthermore, as peroxides used to further improve quick drying properties, the various radical polymerization catalysts listed above can be used as they are.

The appropriate amount of the metal soap used is 0.001 to 1% by weight based on the composition of the present invention.

When using more than 1% by weight, drying of only the surface of the coating film takes priority in the case of thick coating, and internal curing may be delayed.
This is not preferable because the paint film may be colored.

When curing with only metallic soap, liquid painting is common, and especially when cobalt soap is used as a dryer (hardening accelerator), "skinning" may occur in the paint system. Therefore, as with general-purpose alkyd resin paints such as phthalic acid resin paints, it is desirable to add a small amount of an antioxidant such as methyl ethyl ketoxime as an anti-skinning agent.

Furthermore, when using the above-mentioned peroxides, curing is extremely rapid, so two-component coatings are common.

The appropriate amount of such peroxides to be used is within the range of 0.001 to 1% by weight based on the composition of the present invention.

If the amount exceeds 1% by weight, the gel time becomes very short, resulting in poor coating workability and the performance of the resulting coating film, which is not preferred.

The thus obtained coating resin composition of the present invention is applied to coating large-scale machinery made of M gold, such as industrial machinery, agricultural machinery, large-sized vehicles, or land-based structures as described above.

Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified.

Reference Example 1 [Steel production example of fatty acid-modified vinyl copolymer (A)] 500 parts of xylene was charged into a four-eye flask equipped with a thermometer, a reflux condenser, and a stirrer, and heated to 120°C while introducing nitrogen gas. At the same temperature, a mixture consisting of 172 parts of methyl methacrylate, 197.5 parts of styrene, 130.5 parts of glycidyl methacrylate, and 3 parts of tert-butyl perbenzoate was added dropwise over 5 hours. After the polymerization was completed, the polymerization was continued until the non-volatile content (NV) reached 49.3%, and then 218 parts of dehydrated castor oil fatty acids were added and the temperature was raised to 140°C until the acid value became 3 or less. After the addition reaction, xylene 2
When 16 parts were added, NV was 49.9%, Gardner viscosity at 25°C (hereinafter the same) was T3-U, acid value was 7 months.
A transparent objective copolymer with a Gardner color number of 1 to 2 (A
) solution was obtained.

Hereinafter, this will be abbreviated as copolymer (A-1).

Reference Example 2 (same as above) Into the same flask as in Reference Example I, 5% of 1so-butanol was added.
00 parts and 10 parts of tert-butyl perbenzoate
The temperature was raised to 110°C while introducing nitrogen gas.
At the same temperature, 250 parts of styrene, 65 parts of n-butyl acrylate, 17 parts of β-hydroxyethyl methacrylate
A mixture consisting of 5 parts of acrylonitrile, 15 parts of acrylonitrile, and 10 parts of tert-butylperoxy-2-ethylhexanoate was added dropwise over 5 hours, and the polymerization reaction was continued even after the addition was completed until the NV reached 4969%. Then, 318 parts of dehydrated castor oil fatty acid was added and the temperature was slowly raised to 200°C while distilling off 1so-butanol, and the addition reaction was carried out at the same temperature until the acid value became 3 or less.
Xylene was added to adjust the NV to 50%.

The objective copolymer (A) obtained here is transparent and has an NV of 5.
0.1%, the viscosity was ST, 8, and the number of colors was 1 to 2.

Hereinafter, the solution of this copolymer (A) was converted into copolymer (A-2).
It is abbreviated as

Reference Example 3 (Same as above) NV was prepared in the same manner as Reference Example I, except that the same amount of soybean oil fatty acid was used instead of dehydrated castor oil fatty acid.
A transparent solution of the target copolymer (A) having a viscosity of 49.2%, a viscosity of 1-T, an acid value of 1.8, and a color number of 1 to 2 was obtained.

Hereinafter, this will be abbreviated as copolymer (A-3>).

Examples 1 to 3 Copolymers (A-1) to (A-3) obtained in Reference Examples 1 to 3
) so that the PWC is 40%,
20J [rutile type titanium oxide manufactured by Ishiya Sangyo Corporation] and milled each mixture in a sand mill for 30 minutes to prepare an enamel base. [Monocizer TD-
1500J (trimethylolpropane trimethacrylate manufactured by Dainippon Ink & Chemicals), a dryer (metallic soap) and "Disparon #5" as a skin-preventing agent.
Add 01J (Kusumoto Kasei @ product), then add xylene/
Dilute with a thinner of 1so-butanol/[Tsurpetz #100J (isoparaffinic mixed solvent manufactured by Exxon, USA)/Cellosolve acetate 4/2/3/1 (weight ratio) using a Ford Cup 4 for 25 seconds. Various paints were prepared.

That is, the paint composition before diluting with thinner is as follows.

Fatty acid modified vinyl copolymer 108 parts [Tybake R-820J 40'' Monocizer TD-1500J 6J 24% lead naphthenate 1.5J 6% cobalt naphthenate 0.6〃 [Disparon #501J O,6〃 Then, each Paint was applied onto a zinc phosphate-treated steel plate to a dry film thickness of 25 to 30μIn, and heated at 20°C.
After being allowed to stand for 7 days, it was subjected to a coating film performance test.

The results are summarized in Table 1.

Comparative Examples 1 to 3 “Monocizer TD-15iJ” to be added after pigment grinding
12 of each copolymer (A-1), (A-2) or (A-3) to be used for the enamel base.
Examples 1 to 3 except that the amount was increased to
A cured coating film was obtained in the same manner as in 3, and then each coating was
A performance comparison was made for 11M. Those results are the first
They are summarized in the table.

Ultimately, the paint formulations in each of these comparative examples before being diluted with thinner are as follows.

Fatty acid modified vinyl copolymer 114 parts [Tybake R-820, 140 parts 24% lead naphthenate 1.5J 6% cobalt naphthenate 0.6 [Disbaron #501J, 0.6] Examples 4 to 6 [Mono Instead of Sizer TD-1500J, the same amount of [Monocizer TD-1520J (1,6-hexanethiol dimethacrylate manufactured by the same company), r9EG-AJ (
polyethylene glycol diacrylate manufactured by Kyoeisha Yushi Kagaku Kogyo■ and rBP-2EAJ (bisoxyethylated bisphenol A diacrylate manufactured by the same company)
The same procedures as in Examples 1 to 3 were carried out, except that each of the following examples was changed to be used in the manner shown in Table 2. However, the fatty acid-modified vinyl copolymer (A) was fixed only to the copolymer (A-1) obtained in Reference Example 1.

The results of the coating film performance test are summarized in the same table.

In addition, the results of Example 1 are also listed in the same table.

Reference Example 4 [Preparation example of fatty acid-modified vinyl copolymer (A)]
In a flask similar to Reference Example 1, 1 so-butanol
00 parts and 10 parts of tert-butyl perbenzoate were charged, the temperature was raised to 110°C while introducing nitrogen gas, and at the same temperature 125 parts of styrene, 125 parts of vinyltoluene,
A mixture consisting of 250 parts of β-hydroxyethyl methacrylate and 10 parts of tert-butylperoxy-2-ethylhexanoate was added dropwise over 3 hours, and after the addition was completed, the same temperature was maintained for 5 hours to carry out the polymerization reaction. A vinyl copolymer (a-1) with an NV of 49.8% by continuing
A solution of was obtained.

Next, 512 parts of soybean oil fatty acid was added to this resin solution, and the mixture was slowly heated to 20 parts while distilling off 1so-butanol.
The temperature was raised to 0°C, and the addition reaction was allowed to proceed at the same temperature until the acid value became 10 or less, and then a turpentine was added to adjust the NV to 50%.

The objective copolymer (A) obtained here is transparent and has 5 NY.
The solution had a viscosity of 0.2%, a viscosity of R-3, an acid value of 4.1, and a color number of 2 to 3.

Hereinafter, this will be abbreviated as copolymer (A-4).

Examples 7 to 9 and Comparative Example 4 840 parts of the copolymer (A-4) obtained in Reference Example 4 and [
An enamel base was prepared by kneading 400 parts of Thai Bake R-820J with three rolls.

Each enamel base was then used to formulate various paints.

The paint composition in each example is shown in Table 3.

Thereafter, each of the prepared paints was diluted with a turpentine to a Ford Cup & 4 viscosity for 30 seconds, and painted on a zinc phosphate-treated steel plate with a brush to a dry film thickness of 25 to 30 μm at 20°C. So I left it for 7 days.

Next, the coating film performance of each cured coating film was investigated and summarized in Table 4.

Claims (1)

[Scope of Claims] (A) 5 to 50% by weight of a vinyl monomer having a hydroxyl group and/or glycidyl group, and other α,β-ethylenically unsaturated monomers copolymerizable with the above monomer. A vinyl copolymer (a-1) obtained by copolymerizing 95 to 50% by weight of
), the iodine value is 100 to 200
70 to 95% by weight of a fatty acid modified blue 1-vinyl copolymer obtained by addition-reacting drying oil fatty acid (a-2) in a proportion of 10 to 60 parts by weight, and (B) polyfunctional acrylic monomer. A resin composition for coating, comprising 30 to 5% by weight of the body as an essential component.