JPS61266474A - Resin composition for paint - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. for paints having excellent dryability and stain resistance, by graft copolymerizing an alpha,beta-ethylenically unsatd. acid glycidyl ester modified with an aliphatic acid with a copolymerizable monomer in the presence of an oxidative polymerization alkyd resin. CONSTITUTION:A (semi)drying oil fatty acid (e.g.: linseed oil fatty acid) is reacted with an alpha,beta-ethylenically unsatd. acid glycidyl ester (e.g.: glycidyl acrylate) to produce a fatty acid-modified monomer. The fatty acid-modified monomer is graft-copolymerized with other copolymerizable monomer (e.g.: acrylic acid) in the presence of an oxidative polymerization alkyd resin to obtain an intended resin compsn. for paints. The oxidative polymerization alkyd resin can be obtained, e.g., by reacting a (semi)drying oil with a polyhydric alcohol (e.g.: glycerin), forming a monoester by means of an ester exchange reaction and reacting the monoester with a polybasic acid( e.g.: phthalic anhydride).

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a resin composition for paints, and more specifically, a resin composition for paints that has improved drying properties, stain resistance, and repaintability and is made of a novel oxidation-polymerized alkyd craft acrylic resin. The present invention relates to a composition.

PRIOR ART Conventionally, so-called medium oil or long oil alkyd resins containing a large amount of drying oil or semi-drying oil as a component have been used as resins for air-drying paints that are crosslinked by air oxidation. However, these resins often have slow initial drying properties or problems with long-term weather resistance. In order to overcome these drawbacks, alkyd craft acrylic resins, which are obtained by graft polymerizing thermoplastic acrylic resins to these alkyd resins, have been studied and used. However, considering the synthesis method of current alkyd and grafted acrylic resins, it is difficult to imagine that all thermoplastic acrylic resins are grafted with alkyd resins, and during oxidative curing, thermoplastic resins that do not participate in crosslinking at all The result is that acrylic resin is always present. Therefore, even after the coating film is oxidized and cured, the coating film often remains sticky. For this reason, flakes and the like are likely to adhere and the coating film is likely to be contaminated.

In order to prevent sticking, it is possible to raise the glass transition temperature of the thermoplastic acrylic resin, but on the other hand, the coating film becomes brittle and its flexibility is reduced.

In addition, since alkyd craft acrylic resin has crosslinking points only in the alkyd resin portion, crosslinking takes time, and shrinkage may occur due to partial dissolution during recoating.

Problems to be Solved by the Invention Therefore, there is a strong need for an air-drying resin composition for paints that has excellent initial drying properties, weather resistance, improved adhesion (staining resistance), and improved recoatability. The present invention has been made to achieve this goal.

Means for Solving the Problems According to the present invention, the above-mentioned object is achieved by producing fatty acid-modified monomers obtained by reacting drying oil fatty acids and/or semi-drying oil fatty acids with α, β, β-ethylene saturated acid glycidyl esters. This can be achieved by using a coating resin composition obtained by graft copolymerizing the compound (A) and another copolymerizable monomer (B) in the presence of an oxidatively polymerizable alkyd resin. “One of the raw materials for producing the resin composition of the present invention is a fatty acid modified by the reaction of a drying oil fatty acid and/or a semi-drying oil fatty acid with an α,β-ethylenic saturated acid lycidyl ester. It is a monomer.

Such monomers can be easily obtained, for example, by reacting drying oil fatty acids and/or semi-drying oil fatty acids with α,β-ethylenic saturated acid lysidyl ester in the presence of a polymerization inhibitor at 80 to 200°C. In this case, an inert solvent may be used.

Drying oil fatty acids or semi-drying oil fatty acids include tung oil fatty acids, dehydrated and mustard oil fatty acids, linseed oil fatty acids, safflower oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, corn oil fatty acids, sunflower oil fatty acids, etc. Any of the usual types may be used. Typical examples of the α,β-ethylenically unsaturated saturated acid lycidyl ester include glycidyl acrylate and glycidyl methacrylate. Other components of the copolymer are other α, β, β-ethylene saturated monomers that can be copolymerized with the fatty acid-modified monomer. Such monomers include acrylic acid, methacrylic acid, their hydroxyalkyl esters, alkyl esters, unsaturated amide compounds such as acrylamide, 1'1 and methacrylamide; styrene, vinyltoluene, α-methylstyrene, etc. Styrenic monomers; unsaturated nitriles such as acrylonitrile and methacrylonitrile;
Examples include vinyl acetate, and one or more of them may be used in combination.

In the present invention, the fatty acid-modified monomer (A) and the copolymerizable monomer (B) are graft-copolymerized in the presence of an oxidation-polymerizable alkyd resin. The oxidation-polymerized alkyd resin used here is a drying oil or semi-drying oil, such as linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, etc., or coconut oil is added to such drying oil or semi-drying oil. A monoester is produced by transesterification by reacting an oil or oil mixture with a non-drying oil such as sunflower oil with a polyhydric alcohol such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc.
Then polybasic acids such as phthalic anhydride, isophthalic acid,
Ordinary oxidative polymerization type obtained by reacting succinic anhydride, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, fumaric acid, trimellitic anhydride, etc. It is an alkyd resin.

When the fatty acid-modified monomer (A) and the copolymerizable monomer (B) are copolymerized using an initiator in the presence of such oxidation-polymerizable alkyd resin, unsaturated bond sites in the alkyd resin,
Alternatively, radicals are generated at the unsaturated bond sites of monomers (A) and (B) and polymerization proceeds, resulting in an acrylic resin grafted with an oxidatively polymerized alkyd. Oxidative polymerization points derived from the monomer are introduced, and the alkyd part also contains oxidative polymerization points, so the amount of unsaturated double bonds in the entire resin increases, resulting in an increase in crosslinking points and the occurrence of shrinkage due to recoating. Since the acrylic part is also three-dimensional, the occurrence of adhesion due to the acrylic part is improved, and it is extremely useful as a vehicle for an excellent air-drying exterior top coat.

In addition, even if acrylic resin that is not grafted is mixed in the resin composition, oxidation polymerization points are introduced into the acrylic resin itself and the acrylic resin itself becomes three-dimensional, so stickiness after the coating film dries is avoided. Ru.

In the present invention, fatty acid modified monomer (A) and monomer (B)
and oxidation-polymerizable alkyd resins are used in combination in extremely wide ranges depending on the purpose of use, but the amount of fatty acid-modified monomer is usually 2 to 20% of the total solids.
It can be appropriately selected within the range of weight %. This is because if it is less than 2%, there will be too few crosslinking points in the acrylic part even if it undergoes oxidative polymerization, and no improvement in performance will be observed.On the other hand, if it exceeds 20%, the number of crosslinking points will increase and oxidative polymerization will proceed too much, resulting in poor flexibility. This is because a decrease in

In addition, the amount of oxidative polymerization type alkyd resin is 10 to 9 of the total solid content.
It is preferably within the range of 0 weight M%.

This is because if it is less than 10%, curing due to oxidative polymerization is not observed much, and if it exceeds 90%, a decrease in initial drying properties and weather resistance is observed.

In the above copolymerization, a conventional method of heating using a conventional radical polymerization catalyst in a suitable solvent is used, and it is particularly preferable to use an organic peroxide as the catalyst.

The resin composition of the present invention is particularly useful for air-drying paints, but of course it can also be accelerated in curing using a metal dryer, whereby the resin itself is three-dimensionally cross-linked and hardened by oxidation, forming a tough coating film. be given

Pigments, colorants, resins, and other additives can be added as desired when forming paints, and the paints can be applied to various materials by dipping, brushing, spraying, roll coating, etc. A paint using the resin composition of the present invention has excellent drying properties, stain resistance (adhesiveness), and recoatability, and is particularly useful as a top coat for external coatings such as galvanized iron roofs.

The present invention will be explained below with reference to Examples. Parts and percentages are by weight unless otherwise specified.

Production Example 1 Stirrer, reflux device, water separator, rectification column, temperature control device,
940.0 parts of linseed oil in a flask equipped with a nitrogen introduction tube;
222.2 parts of pentol and 0.7 parts of lithium hydroxide were charged, and transesterification reaction was carried out at 240°C for 30 minutes.

Then, 240.2 parts of phthalic anhydride M, 15 parts of azelaic acid
After charging 2.5 parts and 50 parts of refluxing Kijirole and reacting at 240° C. for 6 hours under a nitrogen stream, mineral turpentine was added to adjust the nonvolatile content to 80% to obtain an oxidative polymerization type alkyd resin. This alkyd resin had a nonvolatile content of 80.3%, a viscosity (Gardner at 25° C.>2, an acid value of 5.2, and a number average molecular weight of 2,700).

Production Example 2 Stirrer, reflux device, water separator, rectification column, temperature control device,
In a flask equipped with a nitrogen introduction tube, 851.2 parts of soybean oil, 407.6 parts of trimethylolpropane, and 0 lithium hydroxide were added.
．． 7 parts were charged and the transesterification reaction was carried out at 240°C for 1 hour. Then anhydrous) '541.3 parts of tarric acid and 70 parts of refluxing kijiroru were charged, and after reacting for 7 hours at 240°C under a nitrogen stream, mineral turpentine was added to reduce the non-volatile content to 8.
The amount was adjusted to 0% to obtain an oxidative polymerization type alkyd resin. This alkyd resin has a nonvolatile content of 79.4%, a viscosity (25°C Gardner) ZI Z2, an acid value of 4.9, and a number average molecular weight of 430.
It was 0.

Manufacturing example 3 237 parts of linseed oil fatty acid and methacrylate in the flask.

119 parts of glycidyl oxalate, 20.4 parts of hydroquino, 0.2 parts of tetraethylammonium bromide, and 89 parts of mineral turpentine were added, and while stirring, the
Carry out the reaction at °C. The addition reaction between epoxy groups and carboxyl groups was monitored while measuring the amount of residual carboxyl groups. The reaction took approximately 3 hours to complete.

Production Example 4 A flask was charged with 236 parts of safflower oil fatty acid, 131 parts of glycidyl methacrylate, 0.4 parts of hydroquinone, 0.2 parts of tetraethylammonium bromide, and 92 parts of mineral turpentine, and heated to 1'30 to 140°C while stirring.
Perform the reaction. The addition reaction between epoxy groups and carboxyl groups was monitored while measuring the amount of remaining carboxyl groups.

The reaction took approximately 4 hours to complete.

Example 1 150 parts of the alkyd resin of Production Example 1 and 150 parts of mineral turpentine are charged into a flask equipped with a stirrer, a cooler, and a temperature controller U1 nitrogen inlet tube, and the temperature is raised to 120°C. 120℃
while keeping it. 40.2 parts of styrene, 66.3 parts of methyl methacrylate, 112 parts of 2-ethylhexyl methacrylate
A monomer initiator mixture prepared by adding 4.8 parts of t-butyl peroxybenzoate to a monomer mixture of 49.5 parts of lauryl methacrylate and 15.0 parts of the addition reaction product of Production Example 3 was heated for 3 hours. was added dropwise into the flask, and polymerization was carried out for 30 minutes while maintaining the temperature at 120°C. Next, mineral turpentine 12
A mixture of 1.2 parts of 0 parts t-butyl peroxybenzoate was added dropwise into the flask over 1 hour, polymerization was further carried out at 120°C for 2 hours, 24.2 parts of mineral turpentine was added, and oxidative polymerization type alkyd craft acrylic resin was added. Obtained. This alkyd grafted acrylic resin had a non-volatile content of 54.5%, a viscosity (25° C. Gardner) YZ, an acid value of 1.8, and a number average content of 12,000.

Examples 2 to 6 and Comparative Examples 1 to 2 Resins were synthesized in the same manner as in Example 1. The composition of monomers etc. is shown in Table-(1).

Above, 64 parts of alkyd grafted acrylic resin of each Example and Comparative Example, 10.0 parts of color pigment, and 11.0 parts of extender pigment.
The film performance of the paint obtained by adding and dispersing 3.0 parts of additives, 3.0 parts of additives, and 12.0 parts of mineral turpentine is shown in Table (2).

(Margin below) Note 1) Drying property Curing time based on JIS-54005,8.

◎ Within 6 hrs 0. 6-16 hours.

△　16～24　hrs.

X 24-48 hrs.

XX 48 hrs or more Note 2) Adhesive JIS-54006.8 non-adhesive test (drying condition 50℃ x 24 hrs) Note 3) Erichsen sample was applied to a galvanized iron plate and dried at 50℃. After drying for 7 days, Erichsen test is carried out.

Note 4) Drop one drop of turpentine on the turpentine spot coating and observe the state of the coating after the turpentine evaporates. Stiffness indicates poor curing.

◎　No abnormalities ○ Almost no abnormality Δ There is a little bit of stiffness Note 5) Weather resistance W-0-M Gloss retention rate after 1000 hours (%) ◎ 70% or more 0 70-50% △　50~30% X　　　30~10% ×× 10% or less Note 6) Contamination Contamination after 1 month of natural exposure patent application agent

Claims (1)

[Claims] α, β- in drying oil fatty acids and/or semi-drying oil fatty acids
A fatty acid-modified monomer (A) obtained by reacting an ethylenically unsaturated acid glycidyl ester and another copolymerizable monomer (B) are graft-copolymerized in the presence of an oxidation-polymerizable alkyd resin. A resin composition for paint obtained by