JPS62277476A - Matte coating material composition - Google Patents

Abstract

PURPOSE:A matte coating material composition, obtained by containing fine powdery silica and specific acrylic oligomer without changing hue with a change in coating condition and requiring post-treatment. CONSTITUTION:A composition obtained by blending (A) fine powdery silica with (B) an acrylic oligomer containing a basic monomer having tertiary amino group in an amount of >=20wt% based on constituent monomers and having 600-12,000mol.wt. The component (A) is preferably blended in an amount of 1-500% expressed in terms of solid weight ratio based on the component (A).

Description

3. Detailed Description of the Invention Technical Field The present invention relates to a matte coating composition, and more particularly to a matte coating composition containing finely powdered silica and a specific acrylic oligomer.

BACKGROUND OF THE INVENTION Matte coating compositions have been proposed in which finely powdered silica is added as a matting agent. However, the hue of such paints varies greatly depending on whether the silica is coated with cold or damp hemp or +su6-cut; For paints that are not very effective and have a large hue change, you can age the paint overnight and use it, or use shift toning that predicts the direction in which the hue will shift.1 If a problem occurs, you can retouch and re-tone the color later. Only passive measures such as doing so could be taken.

Problems to be Solved by the Invention Therefore, a matte coating composition containing finely powdered silica as a matting agent, which does not cause hue changes due to changes in coating conditions, and which prevents aging of the coating before coating. There is a need for a coating composition that does not require troublesome post-treatments such as color adjustment, shift toning, and retoning, and it is an object of the present invention to provide such a matte coating composition.

Means for Solving the Problems According to the present invention, the above-mentioned object is obtained by using finely powdered silica and a basic heptamer having a number average molecular weight of 600 to 20% by weight or more of the implanted monomer having a tertiary amino group. 12,000 acrylic oligomers.

The acrylic oligomer used in the present invention is a polymer having a number average molecular weight of 600 to 12,000, in which 20% by weight or more, preferably 30% by weight or more of the constituent monomers are basic monomers having a tertiary amino group. Such an acrylic oligomer is prepared by using a basic hexamer having a tertiary amino group and an addition-polymerizable unsaturated bond and another addition-polymerizable monomer at least 20% by weight of the former, and an appropriate initiator in an organic solvent. It is conveniently produced by a commonly used solution polymerization method, and its molecular weight is controlled to about 600 to 12,000.

Examples of the basic monomer having a tertiary amino group include dimethylaminomethyl acrylate.

Diethylaminomethyl acrylate, dibutylaminomethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, di(t-butyl)aminoethyl acrylate, diisohexylaminoethyl acrylate, diethylaminoethyl acrylate, di(t-butyl)amino Examples include hexyl acrylate, the corresponding methacrylates, 4-vinylpyridine, 2-vinylpyridine, 2-methyl-5-vinylpyridine, and the like. However, the present invention is not limited to these.
Any basic monomer can be used as long as it has a tertiary amino group and an addition-polymerizable unsaturated bond. These can be used alone or in a mixture of two or more.

Other addition-polymerizable monomers to be polymerized with the basic hexamer are those commonly used in the production of vinyl resins. Preferred are any monomers other than acidic monomers, which can be roughly divided into the following groups.

(1) Hydroxyl group-containing monomers, such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, allyl alcohol, methalyl alcohol, and the like.

(2) Polymerizable amides, such as acrylic amide and methacrylic amide.

(3) Polymerizable nitriles, such as acrylonitrile and methacrylate trile.

(4) Alkyl acrylate or methacrylate,
For example, methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate and the like.

(5) α-olefins, such as ethylene, propylene, etc.

(6) Vinyl compounds, such as vinyl acetate and vinyl propionate.

(7) Diene compounds, such as butadiene, isoprene, etc.

Furthermore, if the amount of basic monomer is sufficient, acidic monomers such as carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid can also be included.

In any case, in the present invention, the amount of the basic heptamer having a tertiary amino group in the acrylic oligomer must be at least 20% by weight of the monomer, and if it is less than this, the effect of preventing hue change is insufficient.

Also, the number average molecular weight of acrylic oligomer is about 6.
If it is less than 0.00, the color stability over time will be poor, and if it is less than 120.
It has been found that when it exceeds 00, the compatibility with the main resin deteriorates.

The amount of acrylic oligomer added depends on the amount of silica, the type of paint, the composition of the acrylic oligomer, etc., but usually,
1 to 500% by weight of solid content based on fine powder silica
, preferably within the range of 1 to 300% by weight.

When the acrylic oligomer is less than 1% by weight of the silica, the effect of preventing hue change is small, and when it exceeds 500% by weight, the coating film becomes glossy and the matte effect is reduced.

The acrylic oligomer can be added to the paint together with the finely powdered silica and mixed by stirring, or the finely powdered silica can be previously treated with the acrylic oligomer and then added to the paint.

Although the reason why hue change is effectively prevented by adding an acrylic oligomer to a coating composition made of finely powdered silica has not yet been fully elucidated, the present inventors have It is believed that this is because the amine adsorbs (masks) the silanol groups present in large quantities in the silica, effectively preventing co-aggregation of the finely powdered silica and the pigment (especially Shanin Blue, etc.).

In any case, in the present invention, by adding a specific acrylic oligomer to a matte paint using finely powdered silica, the yield value of the paint is lowered, and changes in hue due to differences in coating conditions can be reliably and effectively prevented. It is.

That is, discoloration due to changes in coating temperature and shearing speed is extremely small, color stability during storage is good, and yellowing during baking is not observed.

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

The following coating compositions were used in these Examples and Comparative Examples.

Production example 1 Oil-free polyester wood 6 coats Blue Paint composition Titanium oxide 14.8% by weight
Carbon black 0.3% by weight
Phthalocyanine blue 2.2% by weight
Lead oxide yellow 2.0% by weight
Oil-free polyester resin varnish 50.3% by weight
Butylated melamine resin varnish 15.1% by weight
Butyl cellosolve 5.1% by weight
Tsurupets 150 5.2% by weight
Weigh the above ingredients and use a paint shaker.

A coating composition obtained by dispersing for 1 hour was used.

Production Example 2 Production of basic acrylic oligomer 1. Acrylic oligomer containing 30% basic monomer based on the total monomers. 160 parts of butyl acetate was placed in a reaction vessel equipped with a stirrer, a thermometer, 2 dropping funnels, and a nitrogen introduction tube. Prepare and raise the temperature to 120°C. Pour 140 parts of methyl methacrylate and 60 parts of dimethylaminoethyl methacrylate into one dropping funnel,
The other dropping funnel was charged with 14 parts of tertiary-butyl peroxy 2-ethylhexanoate and 30 parts of butyl acetate, and dropping was started at the same time and completed in 3 hours. After holding the temperature at 120°C for an additional 30 minutes, 4 parts of tert-butyl peroxyhexanoate and 20 parts of butyl acetate were added dropwise over 1 hour, and the mixture was held at 120°C for 2 hours to complete the polymerization. The resulting varnish was a clear solution with a nonvolatile content of 50% and a viscosity of I. Gel permeation chromatography (G
The number average molecular weight by PC) was 2,510.

2. A varnish was synthesized using the same procedure as for acrylic No. 11 I-1 in which the basic content was 65%, except that the monomers were changed to 70 parts of methyl methacrylate and 130 parts of dimethylaminoethyl methacrylate. The resulting varnish has a nonvolatile content of 50%.
It was a transparent solution with a viscosity of GH1 and a number average molecular weight of 2,460.

3. Basic varnish was synthesized in the same manner as in acrylic oligomer 1 with a 100% mer content, except that the 7 mer was changed to 200 parts of dimethylaminoethyl methacrylate. The obtained varnish was a transparent solution with a non-volatile content of 50%, a viscosity of FG, and a number average molecular weight of 2440. Tert-butyl peroxy 2-ethylhexanoate, an initiator, was added in the same manner as in 4.3. The amount was changed to 20 parts, and a varnish was synthesized. The obtained varnish was a transparent solution with a nonvolatile content of 50% and a viscosity B1 molecular weight of 1050.

Using the same procedure as in 5.3, changing the amount of tert-butyl peroxy 2-ethylhexanoate to 4 parts, a varnish was synthesized.6 The obtained varnish had a non-volatile content of 50%, a viscosity of W-x,
It was a transparent solution with a molecular weight of 9,800.

Synthesis was carried out by changing dimethylaminoethyl methacrylate to diethylaminoethyl methacrylate in 6.1.

The obtained varnish was a transparent solution with a nonvolatile content of 50%, a viscosity of IJ, and a number average molecular weight of 25oO.

Synthesis was carried out by changing dimethylaminoethyl methacrylate to diethylaminoethyl methacrylate in 7.3.

The obtained varnish was a transparent solution with a nonvolatile content of 50%, a viscosity of G, and a number average molecular weight of 245o.

Example 1 Two parts of finely powdered silica (average particle size 2.5μ) was added to 100 solids of the coating composition of Production Example 1, and the basic powder obtained in Production Example 2 was added to the uniformly mixed coating composition. 30 monomers
% of acrylic oligomer was added to the finely powdered silica in an amount equivalent to 15% by weight of the solid content, and the mixture was uniformly stirred and mixed to obtain a matte coating composition.

Examples 2 to 10 Various acrylic oligomers with different basic monomer amounts obtained in Production Example 2 were added to the finely powdered silica-containing coating composition of Example 1 in the amounts listed in Table 1 below to form a matte coating composition. Obtained.

Comparative Example 1 A coating composition prepared by mixing finely powdered silica (average particle size: 2.degree. 5.mu.) with the coating composition of Production Example 1 in Example 1 was used as a comparative coating composition.

Comparative Example 2 Same method as Example 1, except that the average particle size of silica was 3.
．． A coating composition was obtained using a 5 μm one.

Next, each of the coating compositions of the above Examples and Comparative Examples was applied to a tin plate using an automatic bar coater to a dry film thickness of 15 μm, and baked at 160° C. for 2 minutes to obtain a coated plate.

All of these paints were adjusted to have a 60° gloss of about 30.

The discoloration of each paint was examined by changing the paint temperature and coating speed (shedding speed) and measuring the color difference using a color difference meter manufactured by Suga Test Instruments.

Discoloration property (1) is measured at 20°C, 4. When a shearing rate of OX 10"scc" is used as the standard, at 20°C, 7. Color difference (△E) from OX 101sec per 1, discoloration (2) is based on a shearing speed of 20°C14, OX 10"sec"1.

Color difference (ΔE) with 40'C17 and OX 101se61
It is. The 60° gloss value of each coated plate was also determined, and the results are shown in Table 1.

(Margin below)

Claims (2)

[Claims] (1) A matte coating composition containing finely powdered silica and an acrylic oligomer having a number average molecular weight of 600 to 12,000, in which 20% by weight or more of the constituent monomers is a basic monomer having a tertiary amino group. (2) The composition according to claim 1, which contains 1 to 500% by weight of acrylic oligomer based on the solid content of finely powdered silica.