JPH0757846B2 - Water-soluble coating composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a baking-type water-soluble paint, which is a type of water-based paint, and an acid-curing water-soluble paint containing a mountain bark, and a method for producing the same.

(Prior art and its problems) The metal surfaces of automobiles, electric devices and their parts are coated to prevent metal corrosion and to give a beautiful appearance. Water-based paint is one type of paint for painting.

Water-based paint is a generic term for water-soluble paints and is made using water-soluble or water-dispersed coating film forming elements (JIS paint term K5500-1068). The water-based paints are roughly classified into powdery water-based paints, synthetic resin emulsion paints, baking-type water-soluble paints and acid-curable water-soluble paints.

The above-mentioned bake-type and acid-curable water-soluble paints have better workability than other water-based paints, that is, when the coating film is coated, such as wrinkles, blisters, pin poles, sagging, etc. It has the advantages that there are few defects that occur between the two and that it has excellent gloss.

However, the coating film obtained by baking after applying the water-soluble paint has a problem that the water resistance and the water-resistant adhesiveness are low depending on the object and the coating film life is short.

Various attempts have been made to solve these problems. One of the specific methods is to passivate the surface of an object to be coated by adding strontium chromate to the paint. However, this method has a drawback in that it uses strontium chromate, which is problematic in terms of environmental hygiene. Another solution is to use a resin containing a small amount of hydrophilic component in combination with an amino resin (JP-A-57-21462). However, the water resistance and water-resistant adhesion of a coating film obtained by coating and baking the water-soluble coating material obtained by this method still do not satisfy the market demand.

Therefore, the inventors of the present invention have made extensive studies in order to solve the problems of the above-mentioned conventional techniques, and as a result, have accomplished the present invention.

The object of the present invention is not only to permanently maintain the dryness, gloss, hardness, acid resistance, alkali resistance, etc., which are the conventional advantages of water-soluble paints, but in addition to this, water resistance and water resistance To provide a water-soluble coating composition having improved properties and a method for producing the same.

(Structure and Action of the Present Invention) The first invention (hereinafter referred to as the first invention) in the present application is a water-soluble coating composition containing a water-soluble coating resin, water, a solvent, and fibrous mountain bark as main components. A fine fibrous mountain bark containing 0.5 to 50 parts by weight of fibrous mountain bark with respect to 100 parts by weight of the resin for water-soluble paint, and said fibrous mountain bark having a diameter of 0.002 to 0.1 μm. The fine fibrous mountain bark is a water-soluble coating composition characterized by being uniformly dispersed in the water-soluble coating composition in an irregular three-dimensional direction.

The second invention of the present application (hereinafter referred to as the second invention)
Is 0.5 to 0.5 parts of mountain bark for 100 parts by weight of resin component of water-soluble paint.
The mountain bark is crushed and mixed by adding 50 parts by weight and water, and the mountain bark is made into a fiber state until the diameter becomes 0.002 to 0.1 μm, and the fiber state fibrous mountain bark is added to the water-soluble paint. A water-soluble paint comprising a crushing and mixing step of uniformly dispersing a mountain bark dispersion coating material, and a mixing step of adding an appropriate amount of a solvent to the mountain bark dispersion coating material and adjusting it to an appropriate viscosity. It is a manufacturing method of a composition.

First, the first invention will be described.

The water-soluble paint resin in the first aspect of the present invention is an alkyd resin, an acrylic resin, an epoxy ester resin, an oil-free alkyd resin, and an amino resin as a curing agent.

Further, the mountain bark used in the present invention is a magnesium-containing clay mineral, and a mineral having a highly reactive hydroxyl group on the surface thereof. Specifically, sepiolite containing hydrous magnesium silicate as a main component, Attapulgite mainly composed of hydrous magnesium aluminum silicate, one or two of these
Use more than one seed.

The mountain skin in the present invention is commonly called a mountain cork (Mounta
in cork), Mountain leather (Mountain leather),
It is a mineral that is also called mountain wood, etc., and sepiolite in Japan is one of these minerals.The magnesium-containing clay mineral itself has the property of absorbing a large amount of water.

The clay mineral crystal is an aggregate of long fibers having a quadrangular cross section with one side of about 0.1 μm, and the aggregate has a large number of pores in the length direction of the fibers.

The fibrous mountain bark referred to in the first invention has a diameter of 0.002 to 0.1 μ.
m is a fine fibrous mountain bark in a fiber state with a length of 0.1 to several μm, and is uniformly dispersed in the resin for water-soluble paint in an irregular three-dimensional direction.

Mountain bark is normally mined from a mine and crushed by a normal method such as a crusher.
It is a particle of 0 μm. That is, the fibrous fibrous mountain bark according to the present invention is different from the mountain bark particles generally known from the past, and has a finer fiber shape with a large slenderness and a large slenderness ratio.

The amount of the fibrous mountain bark and the resin mixed is 0.5 to 50 parts by weight with respect to 100 parts by weight of the resin for water-soluble paint, and in this range, it can be obtained without impairing the advantages of the water-soluble paint. Improves the water resistance of the coating film and the water resistance of the metal plate. In order to obtain a better effect, the amount of mountain bark mixed is most preferably 3 to 20 parts by weight.

When the amount of mountain bark is less than 0.5 parts by weight, the effect of water resistance and water resistant adhesion to the coating film cannot be obtained, and when it exceeds 50 parts by weight, the viscosity of the water-soluble coating composition is It becomes too high and the coating workability is deteriorated, and the gloss of the coating film obtained by baking after application is lost and the aesthetic appearance is impaired.

The water-soluble coating composition in the first aspect of the present invention may contain pigments and additives. As the pigment, there can be used inorganic pigments such as carbon black, red iron oxide, titanium white, organic pigments such as scapine and quinacridone, and extender pigments such as calcium carbonate, talc, clay, magnesium carbonate and barium sulfate.

Further, as the additive, a dryer, a defoaming agent, a leveling agent, a color separation preventing agent or the like can be appropriately used.

In addition to water, butyl cellosolve, ethyl cellosolve, isopropyl alcohol, butyl carbitol and the like can be used as the solvent.

The water-soluble paint composition according to the first aspect of the present invention comprises a water-soluble paint resin, water, and a solvent as main components, and if necessary, pigments and additives, and a fibrous mountain bark having an amorphous shape. They are uniformly dispersed in the three-dimensional direction, and these are adjusted by the above-mentioned solvent to have a viscosity suitable for coating work.

The water-soluble coating composition according to the first aspect of the present invention is applied to the surface of an object to be coated by a known coating method, for example, electrostatic coating, air spray coating, dip coating, etc., and dried to form a coating film. FIG. 1 shows the results of applying the coating material obtained by the present invention to a test plate and observing the coating film with a transmission electron microscope. In the figure, it can be seen that the fibrous mountain bark 1 in the fiber state is uniformly dispersed in the irregular three-dimensional direction.

Next, the second invention will be described.

The second invention is a method for producing the water-soluble coating composition of the first invention.

First, a mountain bark is added to a water-soluble paint at a ratio of 0.5 to 50 parts by weight with respect to 100 parts by weight of a resin content of the paint, and the mountain bark is crushed and mixed, and the mountain bark has a diameter of 0.002 to 0.1 μm. A fibrous mountain bark in which the fibrous state has been fibrous is uniformly dispersed in the resin to obtain a mountain bark dispersion paint (crushing and mixing step). The mountain bark mixed at this time is crushed by an ordinary method, and the particle size thereof may be about 0.5 to 200 μm. Although it may be out of this preferable range, the particle size is
If it exceeds 200 μm, the workability in this process is poor and it requires a long time. Further, in order to facilitate the crushing and mixing in this step, a small amount of solvent may be added to adjust the viscosity.

Usually, the water-soluble paint resin and the mountain bark are hard to mix with each other, and it is difficult to uniformly disperse the mountain bark by a normal mixing method.

Therefore, the crushing and mixing in this step is a method of dispersing by so-called rheological mixing, and is performed by applying shearing force to the mixture of resin and mountain bark. At this time, the resin makes strong contact with the mountain bark, and the mountain bark becomes a fiber state and is uniformly dispersed in the resin. This crushing and mixing can be performed using a disperser such as a sand grinder, a Paignton shaker, a ball mill and the like. For example, when using a sand grinder, a container with a volume of 1 has a diameter of 1 mm.
Put the glass beads of to make the closest packing ratio 45-55%, then put the mountain bark, resin, and if necessary solvent etc., then put the disk in the container at a peripheral speed of 3 m / sec or more It can be crushed and mixed by rotating at a shearing speed of 3 m / sec or more. In this case, if the peripheral speed of the disk is low or the mixing time is short, the crushing and mixing will be insufficient, and the mountain bark will not be in a sufficiently fibrous state.

Next, an appropriate amount of solvent is added to and mixed with the coating material in which the fibrous mountain bark is dispersed to adjust the viscosity to an appropriate level (mixing step).

Here, the pigment, various additives, and the solvent may be added during or at the beginning of the crushing and mixing step (that is, at the same time as the mixing step), but the addition of the solvent may significantly change the viscosity of the resin, so that the crushing and mixing step may be performed. After is desirable.

Next, an example of a method for forming a coating film using the water-soluble coating composition which is the first invention will be described.

In this example, first, a water-soluble paint is prepared, and the mountain bark is added at a ratio of 0.5 to 50 parts by weight with respect to 100 parts by weight of the resin content of the water-soluble paint, and the mountain bark is loosened in the presence of the resin to obtain a fiber state. At the same time, it is dispersed in the resin (crushing and mixing step). At this time, an appropriate amount of solvent is added to the resin, and the resin content is preferably 15 to 65% in the resin solution. The mountain bark added to the water-soluble paint resin may be crushed by a usual method, and its particle size may be about 0.5 to 200 μm. The particle size may be 0.5 μm or less, or 200 μm or more, but if the particles are large, the workability in the crushing and mixing process is poor, and a long time is required.

Usually, the water-soluble paint resin and the mountain bark are difficult to mix with each other, and it is difficult to uniformly disperse the mountain bark by the usual mixing method.

Therefore, the crushing and mixing in this step is a method of dispersing by so-called rheological mixing, and is performed by applying shearing force to the mixture of resin and mountain bark. At this time, the resin makes strong contact with the mountain bark, and the mountain bark becomes a fiber state and is uniformly dispersed in the resin. This crushing and mixing can be performed by using a disperser such as a sand grinder, a paint shaker, and a ball mill. For example, when using a sand grinder, the diameter of a container with a volume of 1
Put 1mm glass beads so that the closest packing ratio is 45-55%, and then add the mountain bark, resin, and solvent if necessary,
It is advisable to rotate the disk provided in the container at a peripheral speed of 3 m / sec or more (that is, a shear rate of 3 m / sec or more) to crush and mix.

In this case, if the peripheral speed of the disk is low or if the time is short, the crushing and mixing will be insufficient, and the mountain bark will not be sufficiently fiberized, and there will be a part that is not partially dispersed.

A solvent, if necessary, a pigment and an additive are added to and mixed with the mountain bark dispersion paint in which the mountain bark is made into a fiber state and uniformly dispersed. Next, the water-soluble coating composition thus obtained is applied to an object to be coated. After coating, apply the temperature of 60-180 ℃ to 10-6
Bake for 0 minutes to obtain a coating. It is essential that the water content in the dry coating film is 5% or less of the coating film weight. If the temperature is less than 60 ° C, the coating film is not sufficiently dried and the water adsorbed on the mountain bark cannot be sufficiently removed. If the temperature exceeds 180 ° C, the temperature will be too high and the water will evaporate rapidly and the coating film will become rough. If the drying time is less than 10 minutes, the temperature must be raised and the coating film becomes rough. In addition, the drying becomes uneven. If the drying time exceeds 180 minutes, the workability deteriorates and the resin hardens before the moisture adsorbed on the mountain bark is sufficiently removed, which is inconvenient.

When the water content of the coating film after curing and drying of the water-soluble coating composition is 5% or more of the weight of the coating film after curing and drying, the mountain bark removes a part of the remaining moisture in the coating film. The ability to adsorb water that newly infiltrates into the coating film from outside the coating film decreases. Therefore, water that newly invades from the outside of the coating film can easily reach the interface between the object to be coated and the coating film, even if the mountain bark is in a fiber state and is uniformly dispersed in the irregular three-dimensional direction. , The effect of water resistance and water resistance adhesion cannot be expected.

According to the method for forming a coating film of a water-soluble coating composition according to this example, the mountain bark was made into a fiber state in the presence of a resin, and the water content in the coating film after curing and drying was 5% of the coating weight. Because of the following, the mountain bark in the coating film still has a high ability to absorb water, and absorbs the water that enters the coating film from the outside of the coating film, and the water reaches the interface between the coating object and the coating film. To deter
It has excellent water resistance and water resistance adhesion.

Further, the water-soluble coating composition of the present invention can also be used by appropriately mixing it with a colloid emulsion coating or an emulsion coating. In addition, when the mountain bark is blended with the resin solution for colloid emulsion paint or the resin solution for emulsion paint and the resin solution is crushed and mixed until the mountain bark is in a fiber state and uniformly dispersed in the irregular three-dimensional direction, the colloid emulsion paint The particles of the resin for emulsion and the resin for emulsion paint fuse together, resulting in gelation. Therefore, it is difficult to mix the mountain bark directly with the resin solution for the colloid emulsion paint or the resin solution for the emulsion paint to make the mountain bar in a fiber state and uniformly disperse the mountain bar in the irregular three-dimensional direction. Therefore, the water-soluble coating composition in which the mountain bark is in a fibrous state and is uniformly dispersed in three-dimensional directions and the colloid emulsion coating composition are mixed and used as an intermediate type coating composition of each coating composition. You can also do it.

(Effect of the present invention) The water-soluble coating composition according to the first aspect of the present invention, in which the fibrous mountain bark is uniformly dispersed, exhibits appropriate thixotropy and good coating workability. Further, since the mountain bark is fibrous and dispersed in the irregular three-dimensional direction even in the dry coating film obtained by the composition, it has water resistance and water resistance adhesion. That is, even if the coating film is immersed in water for a long period of time, the coating film does not peel off from the object to be coated, and it does not peel off even if some force is applied.

According to the method for producing a water-soluble coating composition according to the second aspect of the present invention, the mountain bark is crushed or loosened in the water-soluble coating resin, so that the mountain bark can be easily made into a fiber state, and even in the resin and even in the paint. It can be dispersed.

According to the method for forming a coating film of a water-soluble coating composition according to the second aspect of the present invention, the mountain bark is made into a fiber state in the presence of a resin, and the moisture content in the coating film after curing and drying is 5% of the coating film weight. %, The mountain bark in the coating film still has a high ability to absorb water, and absorbs the water entering the coating film from outside the coating film,
It prevents moisture from reaching the interface between the object to be coated and the coating film, and exhibits excellent effects in water resistance and water resistance adhesion.

(Example) Hereinafter, an example will be described.

First, the method for confirming the water resistance and the water resistant adhesion of the coating film, which was performed in each example, is as follows.

That is, the coated plate is a mild steel plate (SPCD) having a size of 150 mm × 70 mm and a thickness of 0.8 mm, and its surface is degreased with an organic solvent before coating. After coating on these to form a coating film, it was immersed in pure water at 40 ° C and the time until blistering occurred was measured, and this was used as the criterion for judging water resistance.

To determine the water-resistant adhesion, the coating film is immersed in pure water at 40 ° C. for 240 hours, and then 11 cuts at 1 mm intervals are put in the vertical and horizontal directions in the coating film to make 100 1 mm square cells. Then, the cellophane tape was directly adhered to the squares, and then the cellophane tape was peeled from the end of the cellophane tape at a constant speed, and the number of squares remaining without peeling was counted. The larger the remaining squares, the better the water-resistant adhesion.

In detail, the method for producing the water-soluble paint used in the examples of the present invention was reproduced by incorporating a typical method for producing the water-soluble paint which is currently in the market, while other examples are commercially available while in the market. It was selected and purchased in order to see the effect of purchasing resin and arranging a mountain bark on it.

Examples 1 to 9 First, a water-soluble coating resin was prepared.

43.90 parts by weight of safflower oil was placed in a stainless steel reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and heating equipment.
After heating to 0 ℃, adding 16.44 parts by weight of trimethylolpropane and raising the temperature to 220 ℃, litharge
0.02 parts by weight was added and reacted. The reaction was continued at this temperature until 1 part by weight of the obtained product was dissolved in 5 parts by weight of methanol. After completion of the reaction, the product was cooled to 166 ° C., 12.54 parts by weight of butyl carbitol was added, and the mixture was stirred until uniformly dispersed. Then trimellitic anhydride 23.6
After adding 0 parts by weight, the reaction mixture is heated again to 166 ° C.,
Hold at this temperature for 20 minutes. Then, the mixture was further heated at 190 ° C. for 4 hours for reaction. When the acid value of the reaction product reached 35, the temperature was lowered to 170 ° C., and 3.5 parts by weight of phthalic anhydride was added thereto, and the reaction was continued until the acid value became 45. 100 parts by weight of the obtained reaction product was diluted with a mixture of 55 parts by weight of pure water, 6 parts by weight of isopropyl alcohol and 5 parts by weight of 28% ammonia water to obtain a water-soluble coating resin solution. The water-soluble paint resin content was 60%, the viscosity (Gardner) was Z ₄ , and PH was 8.

100 parts by weight of the resin component of the resin solution for water-soluble paint obtained and 10 parts by weight of the resin component of a methylated methylol melamine resin solution (Sumimar M-40W, manufactured by Sumitomo Chemical Co., Ltd., nonvolatile content 80%) as a curing agent Particle size is about 0.1-150μ
10 parts by weight of mountain bark of m was added and mixed by a sand grinder which is a disperser. And the mountain bark dispersion resin solution was obtained. The sand grinder used had a volume of 1, in which 3 disks with a diameter of 80 mm were mounted, and glass beads with a diameter of 1 mm were placed so that the closest packing ratio was 50%. The mixing was performed for 2 hours at a disk peripheral speed of 4 m / sec.
Immediately after the start of dispersion, 4 parts by weight of carbon black as a pigment, 6 parts by weight of calcium carbonate, 0.5 parts by weight of an antifoaming agent, 40 parts by weight of isopropyl alcohol as a solvent, and 29 parts by weight of pure water were added to 100 parts by weight of the resin content after the dispersion was started. Parts were sequentially mixed and mixed to obtain a water-soluble coating composition according to the first invention.

In this water-soluble coating composition, a fiber-stated diameter of 0.
A large number of 002-0.1 μm and 0.1-several μm long bark were uniformly dispersed in the three-dimensional irregular shape, and the mixed bark was almost in a fibrous state.

Next, the coating composition was coated on the coated plate by air spray, baked and dried at 130 ° C. for 20 minutes, and then the water resistance and the water resistance adhesion were investigated. The results are shown in the column of Example 1 in Table 1 together with the coating film hardness (based on JIS K5400) and the coating film gloss (based on JIS K5400). Also, when the coating film was observed with an electron microscope, the mountain bark was in a fiber state as shown in FIG.
It was dispersed in irregular three-dimensional directions.

Furthermore, a water-soluble coating composition in which the amount of mountain bark was variously changed to 100 parts by weight of the resin content of the same water-soluble coating resin solution was obtained.
The water resistance and the water resistance of the coating film obtained by baking were examined in the same manner as in Example 1 before and after coating. The results are shown in Examples 2 to 9 in Table 1. Further, as comparative examples, those in which 60 parts by weight of mountain bark was added (Comparative Example 1), those in which 0.4 part by weight was added (Comparative Example 2), and those not added at all (Comparative Example 3) were also investigated. The results are also shown in Table 1.

In addition, mixing was carried out for 30 minutes by the above sand grinder, and otherwise the dispersion was carried out in the same manner as in Example 1 to obtain a water-soluble coating composition which remained in granular form without converting the mountain bark into a fiber state, The water resistance and water resistance of the coating film obtained by baking after coating were investigated. The results are shown in Comparative Example 4 in Table 1.

As is clear from Table 1, the water resistance and the water resistance adhesion of the present invention are remarkably improved as compared with Comparative Examples 3 and 4.

A composition obtained by rheologically mixing 60 parts by weight of mountain bark with 100 parts by weight of water-soluble coating resin (Comparative Example 1)
As a result of the water resistance and water resistance adhesion test, the result was good, but the appearance of the coating film was poor, and the result of the gloss test was 35, which was inferior to the conventional coating film and could not meet the market needs. .

Furthermore, the hardness and gloss of the coating film were confirmed based on the test results of the implementation order in which the amount of mountain bark was added to 0.5 parts by weight to 50 parts by weight at approximately equal intervals to 100 parts by weight of the resin for water-soluble paint. In consideration of the above, the most preferable range of the amount of mountain bark mixed is 3 to 20 parts by weight. Further, according to the results of Comparative Example 4, even if the mountain bark, which is said to have an improved effect, is mixed, the mountain bark has an irregular three-dimensional direction as a composition confirmation of the water-soluble coating composition due to the difference in the process and the mixing technique. It was shown that it was not evenly dispersed in the water, which did not lead to the effect of water resistance and water resistance adhesion, because the mixing time of the resin solution for water-soluble paint and mountain bark was short. Is.

FIG. 2 shows the results of transmission electron microscope observation of the coating film. From this result, it is understood that the particulate mountain bark 2 is dispersed as it is. That is, it shows that the mountain bark in the water-soluble coating composition needs to be in a fiber state and uniformly dispersed.

Example 10 3.55 parts by weight of acrylic acid, 7.35 parts by weight of N-methylolacrylamide, 16.6 parts by weight of ethyl acrylate, 16.6 parts by weight of methyl methacrylate, isopropyl in a glass-lined reaction vessel equipped with a stirrer, a reflux condenser, and heating equipment. 55.5 parts by weight of alcohol and 0.22 parts by weight of caprylyl peroxide were added, and the mixture was heated under reflux for 16 hours. After that, 230 parts by weight of pure water, 2
10% by weight of 8% ammonia water was added to obtain a water-soluble coating resin solution. Nonvolatile content is 30% viscosity (Gardner) is V-W,
PH was 8.8. 100 parts by weight of the resin content of the obtained resin solution and 10 parts by weight of the resin content of the methylated methylol melamine resin solution (Sumimar M-40W, manufactured by Sumitomo Chemical Co., Ltd., nonvolatile content 80%) as a curing agent Diameter about 0.5-2
10 parts by weight of 00 μm mountain bark was added and mixed by a side grinder of a disperser. And the mountain bark dispersion resin solution was obtained. The sand grinder used had a volume of one, and three disks with a diameter of 80 mm were mounted in it, and glass beads with a diameter of 1 mm were placed so that the closest packing ratio was 50%. The mixing was performed for 2.5 hours at a disk peripheral speed of 4 m / sec.
Immediately after the start of dispersion, 4 parts by weight of carbon black as a pigment, 6 parts by weight of calcium carbonate, 0.5 parts by weight of a defoaming agent, 40 parts by weight of isopropyl alcohol, and 29 parts by weight of pure water were added to 100 parts by weight of the resin content immediately after the dispersion was started. Were sequentially mixed and mixed to obtain a water-soluble coating composition according to the present application.

In this water-soluble coating composition, a fibrous diameter of 0.00
A large number of mountain bark with a length of 2-0.1 μm and a length of 0.1-several μm were uniformly dispersed in the irregular three-dimensional direction.

Next, the coating composition is applied to the plate to be coated by air spray,
After baking and drying, the water resistance and water resistance adhesion were investigated. The results are shown in the column of Example 10 in Table 2 by baking and drying conditions, coating film hardness (in accordance with JIS K5400), coating film gloss (JIS K54
It is shown together with the water content in the coating film after curing and drying. Further, the test results of the coating film obtained by variously changing the baking and drying conditions are shown in Examples 11 and 12 of Table 2. When measuring the water content in the coating film, a water vaporizer (ADP-341,
The measurement was performed using an apparatus in which a Karl Fischer moisture meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd.) was attached to Kyoto Electronics Manufacturing Co., Ltd.).

Example 13 In a stainless steel reaction vessel equipped with a stirrer, a reflux condenser and heating equipment, 46.5 parts by weight of pure water and sodium bisulfite of 0.
Add 0425 parts by weight, 0.00425 parts by weight of sodium lauryl sulfate and heat to 180 ° C., and sequentially add 23.4 parts by weight of styrene, 2.12 parts by weight of methacrylic acid, 17.0 parts by weight of ethyl acrylate, 0.17 parts by weight of potassium persulfate, 7.45 parts by weight of pure water. The mixture was added dropwise. The mixture was heated to 66 ° C for 30 minutes and then for an additional 2.5 hours 6
The reaction was continued at 5 to 66 ° C to obtain a resin solution for emulsion paint. Resin content of the obtained resin solution for emulsion paint 10
3 parts by weight of carbon black, 4.5 parts by weight of calcium carbonate, 0.7 parts by weight of an antifoaming agent, 7.5 parts by weight of butyl cellosolve, and 13.5 parts by weight of pure water were sequentially mixed with 0 parts by weight to obtain an emulsion paint.

100 parts by weight of this emulsion paint and 100 parts by weight of the water-soluble paint composition obtained in Example 11 and cobalt drier 3
Part by weight was added and mixed to obtain a colloid emulsion type coating composition.

This colloid emulsion type coating composition was applied in the same manner as in Example 11, and the water resistance and water resistance adhesion were investigated.
The results are shown in Example 14 in Table 2. That is, it showed good water resistance and water resistant adhesion.

Comparative Example 5 A water-soluble paint was obtained by using the same production method as in Example 10, except that the mountain bark was not added.

100 parts by weight of this water-soluble paint and 100 parts by weight of the emulsion paint obtained in Example 14 were added and mixed to obtain a colloid emulsion type paint.

This colloid emulsion type coating material was applied in the same manner as in Example 11, and the water resistance and water resistance adhesion were investigated. The results are shown in Comparative Example 5 in Table 2. Thus, both water resistance and water resistance were low.

As is clear from Table 2, the water content in the coating film after curing and drying of the water-soluble coating composition is 5% of the coating film weight after curing and drying.
It can be seen that when the content is less than 5%, the water resistance and the water resistant adhesion of the coating film are remarkably superior to the coating film having a water content of 5% or more. In addition, 10 parts of the mountain bark is added to 100 parts by weight of the water-soluble paint resin
By weight, water resistance of a coating film obtained by baking a colloid emulsion type coating composition obtained by mixing a water-soluble coating composition obtained by uniformly dispersing and an emulsion coating composition,
The water-resistant adhesion was several orders of magnitude better than the colloid emulsion-type paint that did not include mountain bark at all.

Example 14 Water-soluble alkyd resin paint (Watersol S-123,
Resin made from Dainippon Ink and Chemicals, Inc., non-volatile content 50%) 100 parts by weight and methylated methylol melamine resin (Sumimar M-40W, manufactured by Sumitomo Chemical Co., Ltd., non-volatile content 80%) as a curing agent 10 parts by weight for 10 parts of mountain bark
Parts by weight were added and mixed with a sand grinder. The sand grinder used had a volume of 1, in which 3 disks with a diameter of 80 mm were mounted, and glass beads with a diameter of 1 mm were placed so that the closest packing ratio was 50%. The mixing was performed for 2 hours at a disk peripheral speed of 4 m / sec. Immediately after the start of dispersion, 4 parts by weight of carbon black, 6 parts by weight of calcium carbonate, 0.5 parts by weight of antifoaming agent, 4 parts of butylcellosolve
A water-soluble coating composition was obtained by sequentially blending 0 part by weight and 29 parts by weight of pure water.

The coating composition was applied in the same manner as in Example 1, and the water resistance and water resistant adhesion of the coating film were investigated. The results are shown in Table 3 and Example 14. In addition, as a comparative example, investigation was also conducted for a case where no mountain bark was added. The results are shown in Table 3, Comparative Example 6.

From the test results of Example 14 and Comparative Example 6, it can be confirmed that the resin used in the present invention has substantially the same effect even when a general commercially available resin is used.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which fibrous mountain hides are uniformly dispersed in the coating film, and FIG. 2 is a diagram showing a state in which particulate mountain hides are dispersed in the coating film. 1 ... Filamentous mountain hide 2 ... Particulate mountain hide

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Sugiura, Aki Prefecture, Aichi Prefecture, Nagakute Town, Aichi Prefecture 1 41, Yokosuka, Yokouchi Central Research Institute Co., Ltd. (72) Inventor, Mitsumasa Horii 1 in 41, Yokochi, Yokosuka Central Research Institute Co., Ltd. (72) Ken Kiku Kiku, Aki Prefecture, 146 Nakago, Nakamachi, Toyota-shi, Aichi Prefecture (72) Inventor, Yukie Hide Okumura, Yamatogaike, Arako-cho, Nakagawa-ku, Aichi Prefecture No. 20 Judgment Panel for Judgment Chief Judge Yoshio Narui Judge Kane Toshitoshi Judge Kakizawa Norio (56) References JP-A-60-152574 (JP, A)

Claims (2)

[Claims] 1. A water-soluble coating composition comprising a water-soluble coating resin, water, a solvent and a fibrous mountain bark as main components, wherein 0.5 parts of the fibrous mountain bark is added to 100 parts by weight of the water-soluble coating resin. ˜50 parts by weight, and the fibrous mountain bark is a fine fibrous mountain bark having a diameter of 0.002 to 0.1 μm, and the fine fibrous mountain bark has an amorphous shape in the water-soluble coating composition. A water-soluble coating composition characterized by being uniformly dispersed in a three-dimensional direction. 2. 0.5 to 50 parts by weight of mountain bark is added to 100 parts by weight of the resin component of the water-soluble paint, and the mountain bark is crushed and mixed, and the mountain bark is made into a fiber state until the diameter becomes 0.002 to 0.1 μm. Along with the crushing and mixing step to obtain a mountain bark dispersion paint in which the fibrous mountain bark in the fiber state is evenly dispersed in the resin, an appropriate amount of a solvent is added to the mountain bark dispersion paint and mixed, and an appropriate amount is added. A method for producing a water-soluble coating composition, which comprises a mixing step of adjusting the viscosity.