JP2715142B2 - Paint composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coating composition, and more particularly to a coating composition comprising a hydrolyzable silyl group-containing vinyl polymer as a main component of a coating composition, and particularly excellent in storage stability. The present invention relates to a coating composition.

(Conventional technology and its problems) Conventionally, a hydrolyzable silyl group-containing vinyl polymer has good adhesion to inorganic materials such as metals and siliceous materials,
It is excellent in water resistance, weather resistance and heat resistance, and can provide a wide range of physical properties by appropriately selecting and combining the vinyl monomers constituting the polymer. Therefore, the above polymer is widely used as a film-forming component of paints, coating agents, sealants, inorganic composite materials and the like.

However, since the hydrolyzable silyl group-containing vinyl polymer is cured by the cross-linking reaction of the silyl group due to water, the viscosity increases or gels when water is mixed in during production, storage, or use. Therefore, it is necessary to avoid mixing of water as much as possible.

However, when a hydrolyzable silyl group-containing vinyl polymer is used as a film-forming component such as a paint, an extender pigment is contained in the paint for coating and decorative properties, workability and functionality.
It is necessary to add various fillers such as a coloring pigment and an inorganic filler, and perform dispersion and preparation.

The filler used at this time always has a certain amount of adsorbed water, and the silyl groups in the polymer are hydrolyzed due to the adsorbed water and the water absorbed during the dispersion by the disperser and during the blending operation. There is a problem that it loses its function due to stickiness or gelation.

Conventionally, in order to solve the above-mentioned problems, the method of heating and drying the filler to be used immediately before use to remove the adsorbed water in advance and the method of dispersing and blending the filler in the paint in a completely closed system are conventionally used. Although the method is performed, it is difficult to completely remove the adsorbed moisture of the filler by drying,
Even if it is sufficiently removed, it re-adsorbs moisture in the air in a short time, so only some fillers without adsorbed water can be used,
Therefore, sufficient decorativeness, workability, and various necessary physical properties could not be imparted to the formed film. In addition, it is very expensive to carry out the preparation of the paint in a completely closed system, and since the sealed storage is also required after the preparation,
Such a method is industrially difficult to implement.

Accordingly, an object of the present invention is to provide a coating composition containing a hydrolyzable silyl group-containing vinyl polymer as a main component of a film-forming component,
Eliminate the mixing of water when adding and dispersing the filler,
An object of the present invention is to provide a coating composition having excellent storage stability.

(Means for Solving the Problems) The above object is achieved by the present invention described below.

That is, the present invention comprises a hydrolyzable silyl group-containing vinyl polymer as a main component of a film-forming component, and is obtained by melt-kneading a thermoplastic resin and a filler compatible with the polymer with a kneader. A coating composition comprising a masterbatch as an additive.

(Action) By melting and kneading the filler with the thermoplastic resin to form a master batch, the moisture adsorbed in the filler is removed by evaporation at the temperature at the time of production of the master batch.

Therefore, if the masterbatch is blended with a paint containing a hydrolyzable silyl group-containing vinyl polymer as a film-forming component,
Moisture entering the paint can be eliminated.

Further, since the filler in the master batch thus prepared is surrounded by the thermoplastic resin, it does not absorb new moisture even when the paint is stored.

Therefore, the hydrolysis of the silyl group of the hydrolyzable silyl group-containing vinyl polymer in the obtained coating composition is prevented, and the storage stability of the coating composition is significantly improved.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

The hydrolyzable silyl group-containing vinyl polymer used in the present invention is obtained by homopolymerization of a hydrolyzable silyl group-containing vinyl monomer or copolymerization with another vinyl monomer.

Examples of hydrolyzable silyl group-containing vinyl monomers include:
For example, vinyl trimethoxy silane, vinyl triethoxy silane, methyl vinyl dimethoxy silane, γ-propyl methacrylate trimethoxy silane, γ-propyl methacrylic acid propyl methyl dimethoxy silane and the like can be mentioned.

Other vinyl monomers that may be copolymerized with the above monomers include, for example, (meth) acrylates, for example, methyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) Examples thereof include nitrogen-containing vinyl compounds such as acrylate, 2-hydroxyl (meth) acrylate, glycidyl (meth) acrylate, acrylonitrile and acrylamide, and aromatic ring-containing vinyl compounds such as styrene.

When the above-mentioned hydrolyzable silyl group-containing vinyl monomer is copolymerized with another vinyl monomer, the amount of the silyl group-containing vinyl monomer used is preferably at least 10 mol% of all monomers. When the amount is less than 10 mol%, the resulting coating film is insufficient in crosslinkability, which is not preferred.

The polymerization of the hydrolyzable silyl group-containing vinyl monomer or the copolymerization thereof with another monomer may be a conventionally known method, and is not particularly limited, but generally, an aromatic solvent, For example, a method in which each monomer is subjected to a lump or split reaction at 50 to 140 ° C. in the presence of a radical polymerization initiator such as benzoyl peroxide in xylene, and a desired hydrolyzable silyl group is produced by these polymerization methods. A vinyl polymer containing is obtained.

The masterbatch used in the present invention is obtained by melting and kneading a filler with a thermoplastic resin and dispersing the filler in the resin.

The thermoplastic resin used in the masterbatch must have strict conditions that have good compatibility with the hydrolyzable silyl group-containing vinyl polymer and do not deteriorate the physical properties of the coating film composed of the hydrolyzable silyl group-containing vinyl polymer. And its selection was extremely difficult.

As a result of intensive studies, the present inventors have found that esterified cellulose, nitrocellulose, or an acrylic resin satisfies the above strict conditions. Among them, cellulose acetate butyrate (hereinafter referred to as CAB) gave the best result. This CAB has particularly good compatibility with the hydrolyzable silyl group-containing vinyl polymer, and does not lower the performance of a coating film composed of the hydrolyzable silyl group-containing vinyl polymer.

The above-mentioned CAB is obtained by acetylating and butylating cellulose, and various types having different degrees of acetylation, butylation and viscosity (molecular weight) are commercially available and can be obtained and used in the present invention. Further, for example, various esterified celluloses such as cellulose acetate having only acetylation and those obtained by acetylation and propylation can also be used in the present invention. CAB is the most advantageous in terms of properties.

The filler used in the present invention is titanium oxide,
Extender pigments such as calcium carbonate, barium sulfate, silica, alumina and clay; organic pigments; colored pigments such as inorganic pigments;
Any known fillers for paints such as glass fibers and inorganic fibers can be used in the present invention, but the present invention is particularly useful for inorganic fillers that readily adsorb moisture.

The amount of the filler used for the thermoplastic resin is preferably used in a proportion of 20 to 500 parts by weight of the filler per 100 parts by weight of the resin.If the amount of the filler used is too small, the amount of the filler relative to the paint may be reduced. Insufficient filling amount, while too much filler is not preferable because it is insufficient in preventing moisture absorption of the filler.

A method for producing a master batch in which a filler is dispersed in a thermoplastic resin is preferably a method in which both are melt-kneaded by a usual kneader such as a roll, a kneader, a Banbury mixer, and an extruder, and at this time, sufficient dehydration is achieved. For 100
The desired master batch is obtained by kneading at a temperature of at least 110 ° C., preferably at a temperature of from 110 to 200 ° C., and then granulating into pellets or flakes. It is also preferable to use a plasticizer such as dioctyl phthalate in order to facilitate the kneading of the resin and the filler. The water content of the master batch thus obtained is usually 0.1% by weight or less, and contains substantially no water. Further, in such a masterbatch, since the filler that easily absorbs moisture is sufficiently surrounded by the thermoplastic resin, it does not absorb moisture even if left as it is.

The coating composition of the present invention is obtained by adding, mixing, and dissolving the master batch in an organic solvent solution containing the hydrolyzable silyl group-containing vinyl polymer. The mixing order of the silyl group-containing vinyl polymer, the solvent, the masterbatch, and other necessary components is not limited at all, but the masterbatch may have a relatively high concentration in a solvent used in advance in the paint or another organic solvent compatible with the solvent. Particularly preferred is a method of dissolving to prepare a mill base and mixing it in a solvent containing a hydrolyzable silyl group-containing vinyl polymer. According to this method, dissolution of the master batch and dispersion of the filler are more easily performed. You can do it.

In the coating composition of the present invention obtained as described above, the hydrolyzable silyl group-containing vinyl polymer contains about 10 to 40.
%, The thermoplastic resin is about 0.5 to 5% by weight, the filler is about 0.1 to 10% by weight, and the solvent is 60 to 80% by weight.

Also, in addition to the hydrolyzable silyl group-containing vinyl polymer, other resins such as epoxy resin and melamine resin are mixed as a film forming component of the coating composition for the purpose of improving the curability of the coating and the properties of the coating film. It can also be used, and of course, a leveling agent, an antistatic agent and other general paint additives can likewise be incorporated as required.

(Effects) According to the present invention as described above, by melting and kneading a filler with a thermoplastic resin to form a master batch, moisture adsorbed in the filler is removed by evaporation at a temperature at the time of manufacturing the master batch. I have.

Therefore, if the masterbatch is blended with a paint containing a hydrolyzable silyl group-containing vinyl polymer as a film-forming component,
Moisture entering the paint can be eliminated.

Further, since the filler in the master batch thus prepared is surrounded by the thermoplastic resin, it does not absorb new moisture even when the paint is stored.

Therefore, the hydrolysis of the silyl group of the hydrolyzable silyl group-containing vinyl polymer in the obtained coating composition is prevented, and the storage stability of the coating composition is significantly improved.

(Examples) Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, "parts" and "%" are based on weight unless otherwise specified.

Example 1 Production of Mill Base (MB-1) 65 parts of CAB381-0.5 (manufactured by Eastman Chemical Products), 35 parts of carbon black FW200 (manufactured by Degussa) and 5 parts of DOP were heated and melted with a mixing roll to prepare a master batch. did. 10 parts of the masterbatch were mixed with xylene, ethyl acetate and MIBK (methyl isobutyl ketone).
It was dissolved in 50 parts of a 1: 1: 1 (weight ratio) mixed solvent (hereinafter referred to as S-1) to obtain a mill base (MB-1).

Production of Hydrolyzable Silyl Group-Containing Vinyl Polymer Solution (A-1) 100 parts of xylene and 50 parts of n-butanol were placed in a reactor equipped with a cooler and a stirrer, and heated to 90 ° C. 40 parts of methyl methacrylate, 20 parts of butyl methacrylate, 20 parts of lauryl methacrylate, glycidyl methacrylate
A mixture of 10 parts, 1 part of acrylic acid, 10 parts of γ-methacryloxypropyltrimethoxysilane and 5 parts of a 10% xylene solution of benzoyl peroxide was quantitatively supplied to the reactor in 3 hours to obtain a hydrolyzable substance having a molecular weight of 40,000. A silyl group-containing vinyl polymer solution (A-1) was obtained.

Preparation of paint A coating composition of the present invention was prepared by uniformly mixing 10 parts of MB-1 and 73 parts of A-1. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Comparative Example 1 In 37 parts of A-1, 3 parts of carbon black pre-dried at 110 ° C. for 24 hours were dispersed with a motor mill (manufactured by Eiger), and 66 parts of A-1 were mixed with 8 parts of this dispersion. Solvent S-1
Was added and mixed uniformly to obtain a coating composition for comparison. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Example 2 A master batch (titanium oxide: 70 parts, CAB: 25 parts and DOP: 5) prepared in the same manner as in Example 1 except that titanium oxide R-820 (manufactured by Ishihara Sangyo Co., Ltd.) was used instead of carbon black.
Parts) 1 part and 4 parts of mixed solvent S-1 to mill base (MB-
2) was obtained.

A coating composition of the present invention was obtained in the same manner as in Example 1 from 1 part of MB-2 and 5 parts of A-1. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Comparative Example 2 20 parts of titanium oxide was added to 80 parts of A-1 and dispersed with a three-roll mill. To 14 parts of this dispersion, 86 parts of A-1 and 16 parts of a mixed solvent S-1 were added. A coating composition of Comparative Example 2 was obtained in the same manner as in Example 1. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Example 3 Phthalocyanine blue 52 instead of carbon black
A master batch (25 parts of cyanine blue and CAB7) prepared in the same manner as in Example 1 using 40K (manufactured by Dainichi Seika Kogyo Co., Ltd.)
5 parts) 1 part and 5 parts of mixed solvent S-1 to mill base (MB
-3) was obtained.

10 parts of MB-3 and 73 parts of A-1 were mixed in the same manner as in Example 1 to obtain a coating composition of the present invention. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Comparative Example 3 To 90 parts of A-1 was added 10 parts of cyanine blue, and the mixture was dispersed with a three-roll mill. To 10 parts of this dispersion, 88 parts of A-1 and 20 parts of the mixed solvent S-1 were added. Comparative Example 3 as in Example 1
Was obtained. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Example 4 Using 45 parts of nitrocellulose SS1 / 8 (manufactured by Daicel), 45 parts of carbon black, and 10 parts of DOP, a mixed solvent of 10 parts and 50 parts of a master batch prepared in the same manner as in Example 1 was used.
From 1 a millbase (MB-4) was obtained.

A coating composition of the present invention was obtained in the same manner as in Example 1 from 10 parts of MB-4 and 94 parts of A-1. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

Example 5 Using 45 parts of Dianal BR77 (manufactured by Mitsubishi Rayon Co., Ltd.), 45 parts of carbon black and 10 parts of DOP, 10 parts of a master batch prepared in the same manner as in Example 1 and 50 parts of a mixed solvent S-1
To obtain a mill base (MB-5).

A coating composition of the present invention was obtained in the same manner as in Example 1 from 10 parts of MB-5 and 94 parts of A-1. The stability of the paint and the performance of the coating film formed on the stainless steel plate were evaluated, and the results shown in Table 1 below were obtained.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masuto Ogushi 2-8-7, Jinnai, Minamata City, Kumamoto Prefecture (72) Inventor Kenichi Watanabe 10-2, Oibocho, Kanazawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Hideaki Kakiuchi 358-49, Yoneshima, Showa-cho, Kita-Katsushika-gun, Saitama (56) References JP-A-60-51753 (JP, A) JP-A-54-129050 (JP, A) JP-A-50-109234 (JP, A)

Claims (4)

(57) [Claims] 1. A master obtained by melting and kneading a thermoplastic resin and a filler which contain a hydrolyzable silyl group-containing vinyl polymer as a main component of a film-forming component and are compatible with the polymer. A coating composition comprising a batch as an additive. 2. The coating composition according to claim 1, wherein the masterbatch contains substantially no water. 3. The thermoplastic resin is an esterified cellulose,
The coating composition according to claim 1, which is a nitrocellulose or an acrylic resin. 4. The coating composition according to claim 3, wherein the esterified cellulose is a cellulose acetate butyrate resin.