JP2674173B2 - Matting agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a matting agent that is preferably used for paints and the like.

(Prior art and problems) In recent years, consumer preferences for paints have been diversified, and one of the trends is that a moderate to low-gloss color tone coating film is preferred to a high-gloss paint film. Came.

Hitherto, as a method of imparting a matting effect to a paint, a method of adding various solid additives to the paint as a matting agent has been adopted, for example, an inorganic pigment represented by calcium carbonate or a silicon compound. Inorganic materials such as and glass fibers have been used. However, the coating film using such a solid additive is flat and lacks in sense of volume and is inferior in designability, and also in terms of coating film performance, the incorporation of an inorganic material increases the hardness of the coating film and increases the particle size of the inorganic material. When the size is 10 μm or more, the abrasion resistance and scratch resistance tend to decrease due to the brittleness that is a characteristic of the inorganic substance itself, and the inorganic material that is a matting agent is an organic resin that is a matrix. However, there were various drawbacks such as poor adhesion to and poor workability of the coating film because the inorganic material itself did not have ductility.

As a method for removing such defects of the inorganic material, for example, a method of using thermoplastic organic polymer particles such as polyethylene, polypropylene and polyester has been proposed. It had poor adhesion and solvent resistance, and had the drawback of melting and diminishing the matte effect. On the other hand, among the organic polymer particles, acrylonitrile (hereinafter referred to as AN) -based polymer particles have various desirable properties such as excellent weather resistance and solvent resistance, and are desirable as matting agents. An AN polymer obtained by a commonly used polymerization method such as aqueous precipitation polymerization, melt polymerization or bulk polymerization has irregular particle shape and size, or the particles are porous. Therefore, it has been difficult to obtain a uniform coating surface from a coating material containing these AN polymer particles.

To address such problems, for example, JP-A-55-106269,
No. 57-126863, etc., a method of using an AN polymer having uniform particles and a size is proposed, and the matting effect is improved by such means, but the production of the AN polymer spherical particles is It involved complicated operations and processes.

(Problems to be solved by the invention) Based on such a situation, the present inventors have conducted diligent studies, and as a result, use an AN fiber having a very short fiber length containing a specific functional group as a matting agent. According to the present invention, the inventors have found that it is possible to provide a delustering agent having excellent designability, weatherability, solvent resistance, and adhesion without producing problems.

That is, the object of the present invention is excellent in designability, weather resistance,
It is to industrially provide a matting agent having practically no problems such as solvent resistance and adhesion.

(Means for Solving the Problems) The above-mentioned object of the present invention comprises a polymer containing 50% by weight or more of AN and contains a functional group having active hydrogen, and has a fiber diameter of 100 μ or less and a fiber length of 100 μm or less. Achieved with acrylic fibers of 3 mm or less.

 Hereinafter, the present invention will be described in detail.

The acrylic fiber used in the present invention needs to be formed of a polymer containing 50% by weight or more of AN, and if it is less than the lower limit, satisfactory solvent resistance and weather resistance are not provided, and as a result, Since the matte effect cannot be obtained, the intended purpose cannot be achieved. Further, the fiber diameter of the fiber is determined according to the thickness of the coating film, but 100μ or less, preferably 40μ or less, and the fiber length needs to be 3mm or less, preferably 1mm or less. When the amount exceeds the upper limit, the coating cannot be made uniform as a matting agent when dispersed in a coating or applied, and the intended purpose cannot be achieved.

Here, the acrylic fiber has a functional group having active hydrogen,
For example, hydroxyl group, carboxyl group, amide group, amino group,
It is necessary to contain at least one kind such as a sulfonic acid group and a sulfuric acid group, and the introduction of such a functional group improves the adhesion to the coating matrix resin. The content of the functional group is 0.2 to 1 with respect to the weight of the acrylic fiber.
The content is preferably 0%, preferably 0.5 to 5%. If it is out of the lower limit, the effect of improving the adhesiveness is small, and if it exceeds the upper limit, the water resistance of the coating film is lowered.

The method of introducing such a functional group is not limited, and known means such as copolymerization of a monomer containing a desired functional group, introduction as a catalyst end, modification of acrylic fiber (hydrolysis, reduction, etc.), etc. May be appropriately adopted, and some of these means may be combined.

The cross-sectional shape of the acrylic fiber may be any shape such as round or irregular shape, but may be flat, eyebrows, triangular, square, Y
Irregular cross-sectional shapes such as a letter, a cross, and a U-shape, among which flat, eyebrows, and triangles are desirable from the viewpoint of the design properties (glitter) of the coating film.

The method for producing such a matting agent is not limited at all as long as a fiber satisfying the desired AN content, functional group content, fiber diameter, and fiber length is obtained as described above, but the AN content,
It can be obtained by cutting acrylic fibers in the form of short fibers or long fibers having a fiber diameter within a desired range to a desired fiber length. When the functional group is introduced by modifying the acrylic fiber, it may be performed before or after cutting.
Here, it is important not to cause fusion between fibers at the time of cutting (plural fibers are pressed against each other at the cutting surface due to the pressure at the time of cutting), and if there is fusion, the fluidity of the paint deteriorates,
A uniform coating film cannot be obtained.

In addition, from the viewpoint of applicability (dispersibility in paint), it is desirable to attach an oil agent to the fiber surface. The type of oil agent cannot be unambiguously determined because it needs to be changed depending on the type of matrix resin or dispersion medium or solvent in the paint,
For water-based paints, for example, nonionic, anionic, or cationic hydrophilic oil agents are preferable, and for drainage paints, for example, fluorine-based or silicone-based hydrophobic oil agents are desirable. The amount of oil agent adhesion is approximately 0.
It is in the range of 1-3%. The procedure for applying the oil agent may be either before or after cutting into the extremely short fiber length, but operability,
Before cutting is desirable from the viewpoint of avoiding fusion between fibers at the time of cutting.

In particular, in order to further improve the fusion property, coatability, etc., a fiber length of 0.5 mm or less, more preferably 0.3 mm or less is desirable, and such a fiber is obtained by, for example, contracting after cutting acrylic fiber after stretching. .

In addition, depending on the final use of the paint, the coating film may be required to have functions such as flame retardancy to nonflammability, antistatic property to conductivity, moisture absorption and water absorption. Acrylic fiber having a function can be appropriately used as a matting agent.

As a method of adding the matting agent of the present invention to a paint, a method usually used, for example, a method of adding and kneading during the production of paint, a method in which the paint diluent is dispersed in advance in a paint diluent and the paint diluent is added to the paint. Various methods such as a method of adding are employed.

At this time, the mixing ratio of the matting agent to the paint is
It is desirable that the amount of the delusterant is 1 to 50 parts, preferably 2 to 30 parts per 100 parts. If the lower limit of the range is not satisfied, a sufficient matting effect cannot be exhibited, and if the upper limit is exceeded, the matting agent cannot be uniformly dispersed in the paint and the intended purpose is achieved. I don't get it.

The paint using the matting agent is not limited, and non-aqueous paints such as acrylics, melamine alkyds, epoxy, phenols, polyesters, silicone acrylics, and vinyls, or water-based paints are used.

(Effects of the Invention) In this way, a matting agent having excellent weatherability, solvent resistance, adhesiveness, dispersibility in a coating material, and excellent designability with a sense of volume can be obtained without requiring special equipment or complicated operations. What can be provided industrially advantageously is the remarkable effect of the present invention.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited by the descriptions of these Examples. The percentages given in the examples are by weight unless otherwise stated.

The solvent resistance, gloss, weather resistance, adhesion, design and dispersibility were measured as follows.

(1) Solvent resistance After drying the fiber as a matting agent, xylol / butanol / cyclohexane / butyl carbitol = 40/1.
After immersion in a mixed solvent of 5/15/30 and storage at 50 ° C. × 300 hours, the weight loss rate was measured.

(2) Gloss Acrylic ester-based polymer residue as a main component
A test paint was prepared by uniformly dispersing a predetermined amount of a matting agent in a 50% aqueous emulsion paint. The paint is rolled to a thickness of about 25μ on a zinc phosphate plate with a thickness of 0.35mm, which is coated with an epoxy-based paint as a primer to a thickness of about 5μ as a primer and then baked. Thus, a coated steel sheet was produced.

The gloss of this steel sheet was measured by a 60-degree specular reflectance (%).

(3) Weather resistance A coated steel sheet was prepared in the same manner as above except that a polyester-based solvent paint was used instead of the acrylic ester-based polymer water-based emulsion paint. After 1000 hours of the sunshine weather meter test, the steel plate before the test was prepared. The color difference ΔE was measured with a Hitachi color analyzer Model 307 as a standard plate.

(4) Designability The glittering feeling of the coated steel sheet produced in the same manner as the above weather resistance measurement was visually evaluated.

◯: There is a feeling of glittering Δ: A little feeling of glittering is observed ×: There is no feeling of glittering (5) Adhesion property A coated steel sheet manufactured in the same manner as the above weather resistance measurement has a radius.
It was wrapped around a 5 mm round bar and the peeled state of the film was observed with a magnifying glass of 10 times.

◯: No peeling of the coating occurs Δ: Some peeling is observed ×: remarkable peeling (6) Dispersibility The appearance of the coated steel sheet produced in the same manner as the above weather resistance measurement was visually evaluated.

◯: The fibers are uniformly distributed. Δ: Some fiber lumps are observed. X: Fiber lumps are noticeable. Example 1 Methacrylic acid, acrylamide or methyl acrylate was used as a monomer to be copolymerized with AN. 5 kinds of AN-based polymers are prepared by changing the type and the amount of copolymerization of the monomers, and the polymers are spun according to a conventional method to obtain a circular cross-section acrylic fiber (fiber diameter 25 μ, nonion-based Oil adhesion amount 0.7%)
Then, the fiber length was reduced to 0 with a cutter manufactured by Matsushita Seiki Co., Ltd.
It was cut into 15 mm to obtain 5 kinds of test fibers (solvent resistance: 0.3% in each case).

Table 1 below shows the results of evaluation of various performances (addition of 20% of the test fiber to the pure coating material).

From the above table, the product of the present invention containing a predetermined functional group (No. 1 ~
The fact that 4) improves the adhesion while maintaining other performances is clearly understood.

Example 2 Three kinds of test fibers were produced in the same manner as in Example 1 No. 1 except that the cross-sectional shape of the fiber was changed as shown in Table 2 below.

 The evaluation results of the designability are also shown in Table 2.

As is clear from the above table, the modified shape method is superior to the circle in terms of imparting a design property (glittering feeling) to the coating film.

Example 3 Three types of test fibers were produced in the same manner as in Example 1 No. 1 except that the amount of oil agent adhesion was changed as shown in Table 3 below.

 The results of dispersibility evaluation are shown in Table 3.

From the above table, apply an oil agent within the recommended range of the present invention (N
It is understood that the dispersibility is improved by o.10-11).

Claims (1)

(57) [Claims] 1. A matting agent comprising a polymer containing 50% by weight or more of acrylonitrile, containing a functional group having active hydrogen, and comprising an acrylic fiber having a fiber diameter of 100 μ or less and a fiber length of 3 mm or less.