JPH0267380A - Acrylic lacquer composition - Google Patents

Abstract

PURPOSE:To prepare an acrylic lacquer compsn. which gives a coating film with excellent gloss, build-up properties and brightness, by using, as an essential component, a copolymer obtd. by copolymerizing t-butyl methacrylate, methyl methacrylate and a monomer component comprising a specific reaction mixture. CONSTITUTION:5-80wt.% t-butyl methacrylate, 5-80wt.% methyl methacrylate, 0.1-10wt.% reaction mixture obtd. by the reaction of 1mol of an alpha,beta-unsatd. carboxylic acid (e.g., acrylic acid) with 0.9-1.3mol of an alkylene oxide (e.g., propylene oxide) in the presence of a catalyst (0.01-10wt.% based on said alpha,beta- unsatd. carboxylic acid) of the formula (wherein R1 is H, CH3; each of R2 and R3 is CH3; n is 1 or 2), if necessary not more than 5wt.% alpha,beta-unsatd. carboxylic acid (e.g., acrylic acid) and, if necessary not more than 89.9wt.% polymerizable monomer component (in a total amt. of all components of 100wt.%) are copolymerized with each other to give a copolymer, which is compounded as an essential component.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to new and improved acrylic lacquer compositions. More specifically, it provides a coating film with excellent gloss, durability, sharpness, weather resistance, and solvent resistance that is useful for various uses such as paints and inks, as well as pigment dispersibility, solvent dilubility, and spray workability. This invention relates to an acrylic lacquer composition that also has excellent drying properties.

(Conventional technology) Acrylic lacquer has been widely known as an acrylic resin paint, and it has superior weather resistance, chemical resistance, water resistance, etc. than alkyd resin paints and other resin paints, so it is a high-quality finish. It is widely used in fields that require

Acrylic lacquers are used to achieve the desired coating performance without three-dimensional crosslinking and curing with amino resins such as melamine resins, incyanate compounds such as tolylene diisocyanate, and epoxy resins. In general, acrylic resins for lacquers have higher molecular weights and higher glass transition points (Tg) than cross-linked acrylic resins, and in order to further improve drying properties, nitrocellulose or cellulose acetate edges are added to the acrylic lacquers. A large amount of cellulose derivatives such as lattice are added.

(Problems to be solved by the invention) Therefore, conventional acrylic lacquers have poor solvent dilutability and atomization during spraying, and the resulting coating film has poor leveling during painting, poor gloss, and poor durability. There are problems such as poor image clarity and poor weather resistance.

In other words, when the molecular weight of acrylic resin is increased or when a cellulose derivative is used, the solvent dilutability is poor, and as a result, a large amount of solvent is required to match the viscosity of the spray etc. The non-volatile content of the paint becomes low,
To obtain a desired coating thickness, the amount of coating must be increased and the coating thickness when wet must be increased. Therefore, vertical surfaces etc. tend to sag, and the dried paint film becomes more faded.

Furthermore, those with a large molecular weight have poor atomization during spraying, resulting in severe roughness of the coating film, difficulty in obtaining a smooth coating surface, and extremely poor gloss and appearance.

As a way to improve these shortcomings, strong solvents or strong solvents with high boiling points are used to improve solvent dilution and spray workability, but this increases the cost and the high boiling point There are problems such as poor drying properties and damage to the base material when painted on plastic base materials, which are not fully satisfied.Also, in order to improve gloss and durability, paints for lacquer For example, when a styrene monomer is introduced into a part of the composition of the acrylic resin, gloss and durability are improved, but yellowing is strong when exposed outdoors and weather resistance is deteriorated.

In addition, general drawbacks of conventional acrylic lacquers include poor pigment dispersibility, which can easily cause problems such as thickening when pigments are mixed together, pigment sedimentation due to agglomeration of primary color paints, and color separation with toning paints. It has been pointed out that the durability and sharpness of images are poor.
(Molar ratio) - Shipman (a) (However, in the formula, R8 is a hydrogen atom or a methyl group, R2 and R3 are each a methyl group, and n is an integer of 1 or 2.) Catalyst ( However, we have proposed an acrylic resin for paints in which the reaction mixture obtained by reacting α, β-unsaturated carboxylic acid with one catalyst is used as a polymerization component.The acrylic resin for paints is Although the dispersibility was significantly improved, solvent resistance, spray workability, weather resistance, thickening properties, solvent dilutability, drying properties, etc. were not fully satisfactory.

On the other hand, in Japanese Patent Publication No. Sho 62-7230, a specific amount of t-butyl methacrylate and other copolymerizable monomers are combined to yield 100! Obtained by polymerizing in a proportionate manner,
It has been proposed that a mixture of a copolymer with a number average molecular weight of 5000 to 5000 and a glass transition point of 60 to 95°C and a fibrillar compound has excellent abrasion resistance and alcohol resistance. However, such human copolymers have problems such as insufficient pigment dispersibility and resulting coating films that are not fully satisfied with gloss, durability, image clarity, etc.

Although acrylic lacquer is often used as a relatively expensive, high-quality, high-grade finishing paint, it has many problems as described above, and there has been a strong demand for improvements.

As a result of intensive research to overcome the above-mentioned problems, the inventors of the present invention have created a coating film with excellent gloss, durability, sharpness, solvent resistance, and weather resistance, as well as pigment dispersibility and Solvent dilutability,
An acrylic lacquer composition with excellent spray workability and drying properties was completed without degrading other properties.

(Means and effects for solving the problems) That is, the present invention provides: (A) t-butyl methacrylate (1) 5-80
Weight section, CB) Methyl methacrylate) (2) 5-80
Weight ratio, (C) 0.9 to 1.3 mol of alkylene oxide per 1 mol of α, β-unsaturated carboxylic acid to the general formula (a) ORs (However, in the formula, R1 is a hydrogen atom or a methyl group, & and R8 each represent a methyl group, and n represents an integer of 1 or 2.) (However, the amount of catalyst used is α,
0°0 per 100% Bk% of β-unsaturated carboxylic acid
Reaction mixture (3) obtained by reacting in the presence of 0.1-10% by weight (CD) α, β-
Polymerizable monomer component consisting of unsaturated carboxylic acid (4) O to 5% by weight and (E) other polymerizable unsaturated monomers (5) 0 to 89.9% by weight (provided that (1), ( 2), (
The total of components 3), (4) and (5) is 100% by weight. This invention relates to an acrylic lacquer composition containing as an essential component a copolymer obtained by copolymerizing

In the present invention, t-butyl methacrylate (1) is used within the range of 5 to 80% by weight in the polymerizable monomer components, but if the amount of t-butyl methacrylate (1) used is less than 5% by weight, it is difficult to obtain When using lacquer compositions for various paints, they tend to have poor gloss, durability, sharpness, solvent dilutability, etc. On the other hand, when the lacquer composition exceeds 80% by weight, spray workability deteriorates. Both are undesirable, and there is a risk of cracking.

Methyl methacrylate (2j is
It is an essential component for improving dryness, weather resistance, and solvent resistance, and is used in an amount of 5 to 80% by weight. If the amount of methyl methacrylate is less than 5% by weight, the drying properties, weather resistance, and solvent resistance may be insufficient when used as the resin coating, while if it exceeds 80% by weight, the spray workability,
It does not cause deterioration in durability, solvent dilutability, or gloss.
Both are unfavorable as they may cause cracks.

The reaction mixture (3) in the present invention contains 0.9 to 1 alkylene oxide per mole of α,β-unsaturated carboxylic acid.
．． 3 moles of a catalyst represented by the general formula (a) ORs (wherein R1 represents a hydrogen atom or a methyl group, Rt and R3 each represent a methyl group, and n represents an integer of 1 or 2) (however, The amount of catalyst used is α
, 0.0 for β-unsaturated carboxylic acid 1oo fk coefficient
1 to 10% by weight). Examples of the α,β-unsaturated carboxylic acid used in this case include (meth)acrylic acid, and examples of the alkylene oxide include ethylene oxide and propylene oxide. This reaction is carried out in the range of 0.9 to 1.3 moles of alkylene oxide per mole of α,β-unsaturated carboxylic acid, but if the amount of alkylene oxide used is less than 0.9 moles, the reaction will not proceed sufficiently. On the other hand, if it exceeds 1.3 moles, the alkylene oxide remains unreacted, which is not preferable.

Examples of the catalysts represented by al used in the production of the reaction mixture (3) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, and diethylamine ethyl methacrylate. The amount used is 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of α,β-unsaturated carboxyl r!R.
The amount is in the range of 5 parts by weight. Catalysts used in the reaction between α, β-unsaturated carboxylic acids and alkylene oxides include: - Generally, saturated tertiary amines such as triethylamine and tributylamine; metals such as iron, chromium, and nickel, or salts thereof, etc. However, when the reaction mixture obtained by using these catalysts is used instead of the reaction mixture (3) of the present invention, it has excellent pigment dispersibility, which is one of the objects of the present invention. It cannot be considered a copolymer.

The reaction mixture (3) is prepared by introducing an alkylene oxide into a mixture of an α,β-unsaturated carboxylic acid and a catalyst represented by the general formula (a), and heating the mixture at 30 to 120°C, preferably at 50°C under normal pressure or increased pressure. It is obtained by heating to a temperature of ~100°C to cause a reaction. In order to prevent polymerization, the reaction is preferably carried out under an air stream and a polymerization inhibitor is added. Examples of polymerization inhibitors used include hydroquinone, hydroquinone monomethyl ether, t-butylhydroxyanisole, p-nitrophenol, and phenothiazine.
An amount in the range of o, oi to 0.1 part by weight based on 0 ONN mass is preferred. The obtained reaction mixture (3) is used as it is as a copolymerization component without being purified by distillation. If the main fraction obtained by distillation purification is used as a copolymerization component, a copolymer having excellent pigment dispersibility, which is the object of the present invention, cannot be obtained. However, it is possible to remove excess unreacted alkylene oxide from the reaction mixture (3) by methods such as air blowing or vacuum distillation.

The reaction mixture (3) thus obtained is an essential component for obtaining the acrylic lacquer composition of the present invention with improved pigment dispersibility, image clarity, and gloss, and the reaction mixture (3) is a polymerizable monomer component. Medium 0.1 to 1O weight ratio, preferably 14 to 5
It is used in an amount of 4 to 5 parts by weight. If it is less than 0.1% by weight, sufficient pigment dispersibility, image clarity, and gloss will not be exhibited, and on the contrary, 10!
If the amount exceeds i-%, water resistance, weather resistance, etc. will decrease.

Examples of the α,β-unsaturated carboxylic acid (4) used in the present invention include carboxyl group-containing unsaturated monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and maleic anhydride. can give. The amount of α, β-unsaturated carboxylic acid (4) used is in the range of 0 to 5% by weight based on the polymerizable monomer components, but in order to highly express the effect of the reaction mixture (3). It is preferable to use it indispensably,
It is suitable to use 0.05 to 35 to 3 parts by weight, preferably 0.08 to 2 parts by weight, in the polymerizable monomer component. 5 weight -
If an amount exceeding 100% is used, water resistance will decrease.

Other polymerizable unsaturated monomers (5) used in the present invention
For example, methyl acrylate, ethyl (meth)
Acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary
t-Butyl methacrylate and methyl such as butyl acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, octyl (meth)acrylate, inoctyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. (Meth)acrylic acid alkyl esters excluding methacrylate; cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclooctyl (meth)acrylate, cyclododecyl (
(meth)acrylic acid cycloalkyl esters such as meth)acrylate; (meth)acrylamide, (meth)acrylonitrile, N,N'-dimethylaminoethyl (meth)acrylate, styrene, α-methylstyrene, vinyltoluene, vinyl acetate, Examples include vinylpyridine and vinylimidazole, and one or more of these can be used.

Other polymerizable monomers (5) are used in an amount of 0 to 89.9% by weight based on the polymerizable monomer components (if necessary). If the usage amount of the monomer (5) exceeds 89.9% by weight, the usage amount of the components (1) to (3) will be less than the amount specified in the present invention, and the characteristics of the present invention will not be satisfied. It will no longer be effective.

However, among the other polymerizable monomers (5), cyclohexyl methacrylate is a monomer that can be preferably used, and 6D
When cyclohexyl methacrylate is used in a polymerizable monomer component at 2 to 75 wt. It exhibits a significant synergistic effect in obtaining superior acrylic lacquer compositions.

The copolymer which is an essential component of the acrylic lacquer composition of the present invention is obtained by polymerizing the polymerizable monomer components consisting of the components (1) to (5). Polymerization can be carried out by well-known methods, such as solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc., but in order to maximize the features of the present invention, solution polymerization is preferred. is preferable.

When employing the solution polymerization method, radical polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, di-tertiary-butyl peroxide can be used as the polymerization initiator, and as the polymerization solvent,
Toluene, xylene and other high-boiling aromatic solvents;
Ester solvents such as ethyl acetate, butyl acetate and cellosolve acetate, and alcohol solvents such as butyl alcohol can be used alone or in combination.

The acrylic lacquer composition of the present invention, which comprises as an essential component the copolymer obtained by the above procedure, is usually a solution in a suitable organic solvent. Furthermore, cellulose derivatives such as nitrocellulose and cellulose acetate butyrate may be blended as necessary.

The organic solvent used to form a solution of the copolymer is not particularly limited as long as the polymerization solvent used in solution polymerization as described above can be used as is, and it can dissolve the copolymer at a relatively high concentration. .

(Effects of the Invention) The acrylic lacquer composition of the present invention provides a coating film with excellent gloss, durability, sharpness, weather resistance, and solvent resistance, and also has excellent pigment dispersibility, solvent dilutability, and spray workability. It has excellent properties such as hardness and drying properties, and can be used as a clear paint.It can also be used as a colored enamel paint by dispersing various inorganic and organic pigments using known pigment dispersion methods. Further, various known additives for paints can be added as necessary.

The paint thus prepared can be applied to wood products, metals, plastics, etc. using general coating methods such as spray coating, roll coating, and brush coating.

(Examples) The present invention will be explained in more detail below using production examples, examples, and comparative examples. In addition, parts in the examples indicate parts by weight, and ``parts'' indicate parts by weight.

Production Example 1 144 parts of acrylic acid, 4.0 parts of dimethylaminoethyl methacrylate, and 0.05 parts of hydroquinone monomethyl ether were placed in a reactor equipped with a washing stirrer, a reflux condenser, a dropping funnel, a thermometer, and a gas blowing tube. The liquid temperature was raised to 70° C. under stirring and an air stream. 122 parts of propylene oxide was dropped there over 3 hours,
The reaction was further continued for 5 hours. During this time, the liquid temperature was maintained at 70°C. Next, the liquid temperature was raised to 100°C, the reaction was continued at this temperature for 2 hours, and then the temperature was lowered. The reaction mixture thus obtained had an acid value of 10 my KOH/! i+.

The hydroxyl value is 345 KOH/! i' was a colorless and transparent liquid substance (hereinafter referred to as [reaction mixture A]).

Production Example 2 One part of methacrylic acid was added to the same reactor used in Production Example 1.
72 parts, diethylaminoethyl methacrylate 4.8
1 part and 0.06 part of hydroquinone monomethyl ether were charged, and the liquid temperature was raised to 70° C. while stirring and under a stream of air. 122 parts of propylene oxide was added dropwise thereto over 3 hours, followed by reaction in the same manner as in Production Example 1, and then the temperature was lowered. The reaction mixture thus obtained had an acid value of 151 vKOH/g and a hydroxyl value of 310 m9 KO.
The H/IO colorless transparent liquid substance (hereinafter referred to as [reaction mixture B]) was obtained.

Example 1 61.1 parts of toluene and 61.1 parts of butanol were charged under a nitrogen gas stream into a four-bottle flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube, and the temperature was raised to 75°C. , 15 parts of t-butyl methacrylate, 49.7 parts of methyl methacrylate, 5 parts of the reaction mixture obtained in Production Example 1, 0.3 parts of acrylic acid, 30 parts of butyl methacrylate, and 0 parts of azobisisobutyronitrile. A polymerizable monomer component consisting of .5 parts was added dropwise over 2 hours, and an additional 75 parts
The copolymer was maintained at ℃ for 4 hours to reduce the non-volatile content to 44.9%.
It was obtained as a solution (referred to as copolymer solution (1)) with a viscosity of Z.

Examples 2 to 6 and Comparative Examples 1 to 4 The same operations as in Example 1 were repeated except that the composition of the polymerizable monomer mixture used in Example 1 was the same as shown in Table 1. Copolymer solutions (2) to (6) and comparative copolymer solutions (1) to (4) were obtained.

Example 7 Copolymer solutions (1) to (6) and comparative copolymer solutions (1) to (4) obtained in Examples 1 to 6 and Comparative Examples 1 to 4
), various pigments were kneaded according to the following procedure to prepare primary color paints, and the pigment dispersibility was tested. The results are shown in Table 2. Further, the obtained primary color paints of each color were mixed according to the following procedure to prepare a toning paint, and the pigment dispersibility was similarly tested. The results are shown in Table 3.

[Preparation of primary color paint] (White paint) Copolymer solutions (1) to (6) and comparative copolymer solution (
White pigment "Tie Bake R-8" was applied to each of 1) to (4).
20" (manufactured by Ishihara Sangyo ■, rutile type titanium oxide) was added so that the resin nonvolatile content/pigment ratio was 1/1 (weight ratio), and kneaded for 30 minutes in a sand mill (using a glass piece. The same applies hereinafter). This is xylene/toluene/butyl acetate=
Paint viscosity was 20 seconds (Ford Cup, %4/25°C) with 1/1/1 (weight ratio) thinner (hereinafter simply referred to as "thinner").

The same applies to the following. ) The sample was diluted as much as possible.

(Black paint) Copolymer solutions (1) to (6) and comparative copolymer solution (
The black pigment “FW-2007” was added to each of 1) to (4).
(manufactured by Degutsusa, carbon black) as resin non-volatile content/
The pigment was added so that the weight ratio was 110.04, and the mixture was kneaded for 30 minutes using a sand mill. This was diluted with thinner in the same manner as in the case of preparing the white paint described above and used as a sample.

[Preparation of toning paint]

Samples of toning paints were prepared by using the above two primary color paints, white and black, obtained using each copolymer solution and blending them in the following blending ratios.

Gray color: white paint/black paint = 90/10 (weight ratio)
Example 8 Copolymer solutions (1) to (6) obtained in Examples 1 to 6 and comparative copolymer solutions (1) to obtained in Comparative Examples 1 to 4
(4) and its acrylic silica compositions 1) to (
6) and comparative acrylic lacquer compositions (1) to (4)
) and titanium oxide (Tiebake R-820,
(manufactured by Ishihara Sangyo ■) was blended to give a pigment weight concentration of 40% and dispersed in a sand mill to prepare white enamel.

Each of the obtained white enamels was applied to a mild steel plate by air spraying to a dry film thickness of 20 μm, and after drying at room temperature for 48 hours, the performance of the coating film was evaluated. The performance of the coating film was evaluated according to the following performance test method in four grades: ◎~O~Δ~×, and the evaluation results are shown in Table 4.

Claims (1)

[Claims] 1. [A] t-butyl methacrylate (1) 5-80
% by weight, [B] 5 to 80% by weight of methyl methacrylate (2), [C] 0.9 to 1.3 mol of alkylene oxide per mol of α,β-unsaturated carboxylic acid, general formula (a) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, R_1 is a hydrogen atom or a methyl group, and R_
2 and R_3 each represent a methyl group, n is 1 or 2
represents an integer. ) (however, the amount of catalyst used is 0% based on 100% by weight of α,β-unsaturated carboxylic acid)
．． 0.1 to 10% by weight of the reaction mixture (3) obtained by reacting in the presence of 0.01 to 10% by weight), 0 to 5% by weight of [D] α,β-unsaturated carboxylic acid (4) and [E ] Polymerizable monomer component consisting of 0 to 89.9% by weight of other polymerizable unsaturated monomers (5) (However, (1), (2), (
The total of components 3), (4) and (5) is 100% by weight
It is. ) An acrylic lacquer composition containing as an essential component a copolymer obtained by copolymerizing. 2. The amount of t-butyl methacrylate (1) is 5 to 78% by weight in the polymerizable monomer component, and cyclohexyl methacrylate is used as the other polymerizable unsaturated monomer (5). An acrylic lacquer composition according to claim 1, wherein the acrylic lacquer composition is used in an amount of 2 to 75% by weight of the ingredients.