JPH0134664B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a dip coating method using a slurry paint in which resin particles are dispersed in water. More specifically, the present invention relates to a method for dipping a slurry paint, which allows a thick coat of uniform thickness to be applied in one coat without sagging, unevenness, bulging, or wrinkles. Dip coating methods for slurry paints have been attracting attention because they allow thick coatings to be formed in one coat and have good coating efficiency. However, in dip coating with such slurry paint, when the object to be coated is pulled up from the dip coating tank, a film is applied to openings such as holes or bent parts of the object to be coated, and when the film is torn, water etc. Since it flows down all at once, it washes away the coating film below the membrane rupture point, which has the disadvantage of causing scratches on the object to be coated or exposing the substrate. As a result, not only is the paint finish poor in that area, but rust may occur as well.
This caused paint film peeling, etc., resulting in a decrease in long-term durability. In order to solve the above-mentioned drawbacks, attempts have been made to add antifoaming agents to slurry paints. The dispersion stability of the resin particles tended to be impaired. In addition, since the paint in the tank is circulated or stirred, the antifoaming agent is dispersed and the antifoaming effect decreases over time, making it necessary to add the antifoaming agent intermittently. Furthermore, the amount of antifoaming agent contained in the slurry paint increased, resulting in a decrease in corrosion resistance, water resistance, etc. of the paint film. Therefore, the addition of antifoaming agents was not a suitable solution. In addition, dip coating with a slurry paint has the disadvantage that clumps tend to form on the horizontal parts of the object to be coated. Therefore, an attempt was made to eliminate the sag by increasing the water dilution of the slurry paint in order to improve the sagging and flow in the horizontal areas, but this method made it impossible to achieve thick film coating, which is a characteristic of slurry paint. was not a suitable solution. An object of the present invention is to provide a coating method that enables thick coating with a uniform film thickness without sagging, unevenness, bulging, wrinkles, etc., without changing the composition of the slurry coating. That is, the present invention is a method of coating an object by dipping it into a dip coating tank containing a slurry-like paint, in which the object to be coated is immersed within at least 1 minute after being lifted from the dip coating tank. This invention relates to a dip coating method for slurry paint, which is characterized by applying air at a wind speed of ~50 m/sec. By the method of the present invention, a homogeneous coating film can be obtained because the film is broken at an early stage, sagging and sagging of the substrate are prevented, and sagging is also eliminated. The paint used in the present invention contains resin particles of about 1 to 80μ in water as a medium with a solid concentration of 10
It is a slurry-like paint that is dispersed in a range of ~70% by weight and further contains pigments or small amounts of additives such as surfactants and thickeners as necessary. The properties of the slurry paint described above are particularly suitable for the method of the present invention. That is, it has a structural viscosity of 100 to 500 CPS after painting (stirring at a rate of 60 rpm with a No. 3 rotor, and measuring the viscosity with a B-type viscometer after 1 minute), and a thixotropic ratio [No. 3 rotor]. at 6r.pm and 60r.pm
A slurry-like paint having a viscosity ratio (viscosity of 6 rpm)/(viscosity of 60 rpm) of 1.5 or more according to Type B viscosity after 1 minute is suitable for the method of the present invention. The resin of the slurry paint may be either a self-curing type or a curing agent-curing type, such as acrylic resin, polyester resin, alkyd resin,
Epoxy resin, epoxy modified polyester resin,
Urethane-modified polyester resin etc. can be used. Particularly in the present invention, a slurry paint that does not easily cause wrinkles or cracks as described below is suitable. That is, (A) (a) consists of an epoxy resin with an average molecular weight of 900 to 3,000 obtained by the reaction of bisphenol A and epichlorohydrin and/or methyl epichlorohydrin, dicyandiamide, a blocked isocyanate compound, and a polyester resin with an acid value of 40 to 250. A composition consisting of 30 to 55% by weight of resin particles with an average particle diameter of 10 to 80μ and (b) 70 to 45% by weight of water, consisting of at least one type of cured product selected from the group consisting of 100 parts by weight, (B ) Polyethylene oxide and/or bentonite with an average molecular weight of 300,000 to 4 million...0.05 to 0.6
Parts by weight, and (C) Nonionic surfactant with HLB value 12 to 16...0.1
It is preferable to use a slurry paint containing 0.5 parts by weight. The resin particles, which are the main components of this slurry paint, are composed of an epoxy resin and a curing agent. The epoxy resin used is one with an average molecular weight of 900 to 3,000 obtained by reacting bisphenol A with epichlorohydrin and/or methylepichlorohydrin. If the average molecular weight is smaller than the above range, it is undesirable because the coating film tends to have wrinkles, the thick film coating properties are poor, and the storage stability of the coating material is also poor. , corrosion resistance deteriorates, which is not preferable. Furthermore, dicyandiamide, blocked isocyanate compounds, and polyester resins can be used as curing agents. Blocked isocyanate compounds are polyvalent isocyanates masked with active hydrogen compounds. The active hydrogen compound has a boiling point of 140 to 250°C, especially
A temperature of 150 to 230°C is preferred. Active hydrogen compounds include oxime types such as methyl ethyl ketoxime, methyl isobutyl ketoxime, and cyclohexanone oxime; lactam types such as γ-butyrolactam, δ-valerolactam, ε-caprolactam, and peptolactam; furfuryl alcohol, benzyl alcohol, and cyclohexanol. Alcohol-based products such as: butyl cellosolve,
Ether alcohols such as phenyl cellosolve, methyl carbitol, carbitol, and butyl carbitol; Amides such as formanilide, acetanilide, benzanilide, and lactoanilide; Imides such as succinimide, maleimide, and phthalimide; or combinations of two or more of these. Mixtures can typically be used. Examples of polyvalent isocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, o-tricidine diisocyanate, dianisidine diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, and isophorone. Diisocyanate, 1-methyl-2,4-diisocyanate cyclohexane, 1-methyl-2,6-diisocyanate cyclohexane, 4,4'-methylenebiscyclohexyl isocyanate, 4,4'-ethylenebis(cyclohexylisocyanate), ω, ω' −
Diisocyanate-1,4-dimethylcyclohexane, ω,ω'-diisocyanate-1,3-dimethylcyclohexane, 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, isopropylidenecyclohexyl diisocyanate, or a mixture of two or more of these It can be used as a representative. Further, the polyester resin used has an acid value of 40 to 250. If the acid value of the polyester resin is lower than the above range, the crosslinking density will be low, resulting in insufficient water resistance, corrosion resistance, hardness, etc. If it is larger than the above range, water resistance and corrosion resistance will be insufficient due to excess carboxyl groups, and further immersion will be difficult. This is undesirable because it reduces the stability of the paint in the paint bath. In addition, the softening point of polyester resin is 30~120℃
Preferably. If the softening point is lower than the above range, resin particles tend to aggregate and the stability of the paint decreases, while if it is higher than the above range, cracks tend to occur in the resulting coating film and the thick coating properties deteriorate, which is preferable. do not have. In the synthesis of polyester resins, the carboxylic acid component is preferably reacted in a proportion of 30 to 70% by weight. Specific examples of the components include (anhydrous) phthalic acid, isophthalic acid, (anhydrous) trimellitic acid,
(anhydrous) pyromellitic acid, tetrahydro (anhydrous)
Phthalic acid, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hymic anhydride, succinic acid, adipic acid, sebacic acid, benzoic acid, para-tertiary butyl Examples include benzoic acid, and these may be used alone or in a mixture of two or more. In the synthesis of polyester resin, the polyhydric alcohol component is preferably reacted in a proportion of 30 to 70% by weight. Specific examples of the components include ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, dipropylene glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, butanediol, pentanediol, hexanediol, 1,
There are 4-cyclohexanedimethanol, (hydrogenated) bisphenol A, etc., and these may be used alone or in a mixture of two or more, and if necessary, in combination with Cardular E (trade name, manufactured by Schiel Chemical Co., Ltd.). In addition, animal and vegetable oils, their fatty acids, petroleum resins, rosin, etc. can also be used as modified raw materials for polyester resins, if necessary. The appropriate mixing ratio of the epoxy resin and curing agent is 3 to 10 parts by weight for dicyandiamide and 10 to 100 parts by weight for blocked isocyanate compounds or polyester resins, per 100 parts by weight of the epoxy resin. It is also possible to add 3 to 100 parts by weight of a mixture of two or more of the three types of curing agents. Furthermore, the resin particles can also contain coloring pigments, extender pigments, or additives commonly used in powder coatings, if necessary. The average particle diameter of the resin particles is suitably 10-80μ, particularly preferably 12-40μ. If the average particle size is smaller than the above range, the cohesiveness of the resin particles will increase,
Further, foaming tends to occur during heating film formation, and on the other hand, if it is larger than the above range, storage stability becomes poor and it becomes difficult to obtain a smooth coating film, which is not preferable. The resin particles used in the present invention can be prepared by a known method,
For example, it is manufactured by mechanically pulverizing the solid resin, spray drying the resin solution, suspending the resin solution in water, removing the solvent, and taking out the solid particles. Next, as the thickener, polyethylene oxide, bentonite, or a combination of both is suitable. Polyethylene oxide has an average molecular weight of 300,000~
4 million, particularly preferably 600,000 to 3 million. If the average molecular weight of polyethylene oxide is smaller than the above range, the viscosity of the paint will be insufficient, the thick film coating properties will be poor, and the resin particles during coating will tend to precipitate, while if it is larger than the above range, the solubility in water will decrease. However, this is not preferable because the stability of the coating material against temperature changes becomes poor, the coating material becomes stringy, and the coating becomes difficult to drip off, making it unsuitable for dip coating. When bentonite is made into a 3% by weight aqueous dispersion
Preferably, the viscosity at 20°C is 5 centipoise or more. If the viscosity of bentonite is less than 5 centipoise, the viscosity of the coating material will be insufficient and the same problems as those of polyethylene oxide will arise, which is not preferable. In particular, the viscosity of bentonite is
Approximately 200 centipoise is suitable. The amount of thickener added is approximately 0.05 to 0.6% by weight in the paint.
is appropriate. Especially in the case of polyethylene oxide alone
0.1-0.5% by weight, for bentonite alone
0.05-0.3% by weight is suitable. If the amount of the thickener added is less than the above range, the viscosity of the paint will be insufficient, while if it is more than the above range, the water resistance and corrosion resistance of the coating film will deteriorate, which is not preferable. Next, the nonionic surfactant preferably has an HLB value of 12 to 16. If the HLB value is smaller than the above range, the fluidity of the paint will be poor, making it unsuitable for dip coating. The nonionic surfactant is suitably added to the paint in an amount of about 0.1 to 0.5% by weight. Nonionic surfactants include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbital fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene higher alcohol ether, polyoxyethylene lanolin derivative, polyoxyethylene castor oil derivative,
Typical examples that can be used include polyoxyethylene alkylphenol formaldehyde condensates, polyoxypropylene polyoxyethylene alkyl ethers, and polyoxyethylene alkylphenol ethers. Next, water is used as a dispersion medium for the slurry paint. It is particularly preferable that the amount of water is about 45 to 70% by weight added to the paint, and within this range the dip coating workability is excellent. In the present invention, the smoothness of the coating film can be further improved by adding 1 to 5% by weight of polyethylene glycol having an average molecular weight of about 2,000 to 10,000 to the coating material. In the present invention, as explained above, a slurry-like paint is placed in a dip coating tank, and the object to be coated is dipped therein to be coated. The immersion coating tank is equipped with a stirring device.
It is also preferable to have a temperature control device and a paint circulation device such as an overflow tank. Slurry paint has structural viscosity, so it is necessary to sufficiently stir the bath to keep the viscosity constant.
It is preferable to use a propeller stirrer or other forced stirring device in combination. Furthermore, since the slurry paint is made by dispersing resin particles with a relatively large particle size, it is preferable to use a pump without sliding parts, such as a diaphragm pump or a roller pump, as the paint circulation pump. When painting, the paint temperature is usually adjusted to a range of 5 to 35 degrees Celsius, preferably 15 to 25 degrees Celsius, and the object to be coated is immersed uniformly, then 0.5 to 1.5 m/s
It is appropriate to raise it by min. In the present invention, immediately after the object to be coated is lifted from the dip coating bath as described above, within at least one minute, the object to be coated is exposed to a wind speed of 3 to 50 mph immediately before the object to be coated.
Apply air at m/sec to open areas such as cracks in the object to be coated,
Breaks the film formed on bent parts and removes clumps that occur on horizontal parts of the object to be coated. As mentioned above, it is preferable to blow air immediately after lifting, and it is necessary to blow the air within one minute at the latest.
If the air blowing period is delayed, the film will naturally rupture, and the water flowing down will push out the underlying paint film, leaving undesirable sagging marks on the paint film. In addition, the scum generated on the horizontal portions of the object to be coated becomes thickened and becomes difficult to blow away even by blowing air. Moreover, as mentioned above, the appropriate wind speed is 3 to 50 m/sec. If the wind speed is lower than the above range, water etc. from the membrane rupture cannot be blown away, and the object of the present invention cannot be achieved. On the other hand, if the wind speed is higher than the above range, the air will be blown more than necessary, the object to be coated will shake more, and additional power costs will be required, which is not practical. In particular, it is appropriate to blow air at a rate of 5 to 50 m/sec to eliminate bulges that occur on horizontal areas of the object to be coated, and to blow air at a rate of 3 to 30 m/sec to break the membrane formed at the openings. Conventionally, it was thought to accelerate the evaporation of water by blowing air at several tens of cm/sec onto the dip-coated object, but at such low speeds, the remaining paint would be blown away. I can't do that and it's not appropriate. The above-mentioned air blowing is preferably carried out above the immersion coating tank in order to collect scattered water and paint, and also because of the timing of the air blowing. In this case, the position where the object to be coated is in contact with the air should be at least 15 mm above the level of the paint in the bath.
Must be separated by at least mm. If this position is too close to the liquid surface, wind will hit the paint in the bath and the water will evaporate, making the paint more likely to thicken, which is undesirable. In addition, the appropriate air blowing time is usually around 30 seconds.
Furthermore, in order to blow off excess paint adhering to the object, the air blowing point to the object to be coated is a point where the membrane formed at openings such as holes, bends, etc. of the object to be coated is ruptured;
It may be applied only to the horizontal part where the bulging occurs, but it may be applied to the entire surface of the object to be coated. The blowing means includes fans such as centrifugal fans and axial fans; blowers such as turbo blowers; compressors such as reciprocating compressors, centrifugal compressors, axial compressors, rotary compressors, and injection compressors; It is appropriate to use a method in which the air generated by a gas transporter passes through piping and is blown out from a nozzle or slit. In this case, the shape of the nozzle or slit outlet is not particularly limited, but circular or linear shapes are practical. Also, the nozzle diameter is 0.1 to 10 mm, especially 1 to 3 mm.
The degree is appropriate. If the nozzle diameter is smaller than the above range, the wind speed in front of the object to be coated will decrease, and as a result, it will be necessary to bring the nozzle quite close to the object to be coated, which is not appropriate in view of the play of the conveyor and the shaking of the object to be coated. Furthermore, if the nozzle diameter is made larger than the above range, the wind speed similarly decreases and the power of the gas transporter becomes labor-intensive, making it impractical. When using a slit, the slit width is preferably about 0.05 to 3 mm, particularly about 0.1 to 2 mm, for the same reason. In the present invention, when continuously dip-coating objects of the same shape, the air flows almost constantly at areas where the membrane ruptures or stagnates, so a nozzle or slit is used so that air can hit the object efficiently. All you have to do is decide the position and fix it. On the other hand, when dip-coating objects of different shapes, the object is rotated or the nozzle or slit is moved so that air can efficiently hit the object. FIG. 1 is a schematic diagram showing an example of the dip coating method of the present invention, and FIG. 2 shows the relationship between the flow direction of the object to be coated (conveyor) and the flow direction of air. Both figures show that a workpiece 2 to be coated is conveyed by a conveyor 3 into a dip coating tank 1, and after being coated, air is blown through between nozzles 4 and 4'. A film tends to form in the holes of the object to be coated, and in order to break the film efficiently, the blower is installed so that the hole of the object to be coated and the nozzle opening are at the same height. In addition, in the present invention, blowing heated air at 100°C or less accelerates the evaporation of water in the dripping paint after membrane rupture or removal of sag, so that a uniform film thickness with no scratches can be achieved. This method is more suitable because it provides a good finish. After applying air to the workpiece as described above, the workpiece is set in an atmosphere of room temperature to 120℃ for 1 to 20 minutes, the paint is drained, water is evaporated, and the workpiece is set for 1 to 20 minutes.
The coating film is cured by heating at 150-220°C for about 10-30 minutes. By the dip coating method of the slurry paint of the present invention, a thick coating film with good coating workability, homogeneity, and excellent corrosion resistance can be obtained. The present invention will be explained below using examples. In the examples, "parts" and "%" indicate "parts by weight" and "% by weight," respectively. [Preparation of resin particles A to F] The formulations shown in Table 1 were uniformly kneaded at 120°C,
After cooling and solidifying, there is a method of mechanically crushing (hereinafter referred to as manufacturing method (2)), or (2) dissolving in methyl ethyl ketone, kneading and dispersing, and spraying it into a large amount of water (20°C) to make it into fine particles, and methyl ethyl ketone is dissolved in water. Resin particles A to F were prepared by a method (hereinafter referred to as manufacturing method ()) of extracting into a phase and granulating (water-containing resin particles). [Slurry paint formulation] The formulation shown in Table 2 was used.

【table】

[Table] Example 1 Paint No. 1 shown in Table 2 was placed in a boat-shaped dip coating tank (height: 2 m, base length: 2 m, top length: 4 m, width: 2 m), and the paint in the bath was pumped by a circulation pump. While circulating the coating material [2.3 (board thickness) x 70 (width) x 500 (length)
A plate-like object with a diameter of 18 mm at a location 250 mm from the top edge, and a hole of 2.3 mm (plate thickness) at a location 100 mm from the top edge.
A small dull steel plate made by vertically welding a plate-like material of × 70 (width) × 20 (length) mm] was immersed in the bath, pulled up, and
After a few seconds, compressed air was blown by a reciprocating compressor toward the horizontal part of the object to be coated and the holes on the immersion coating tank 60 cm above the paint liquid surface. Air blowing conditions Nozzle diameter: 1.5mm Distance between nozzle opening and object to be coated: 15cm Air speed just before the object to be coated: 5 m/sec Air blowing time: 30 seconds After blowing, leave the object to be coated at 100℃ for 10 minutes, then 180℃,
Baked for 30 minutes. The results are shown in Table-3. Example 2 Painting was carried out in the same manner as in Example 1, except that paint No. 2 was used instead of paint No. 1 in Example 1, and air was blown under the following conditions using a blower. Air blowing conditions Slit width: 2.5 mm Distance between slit opening and object to be coated: 15 cm Wind speed just before the object to be coated: 5 m/sec Air blowing time: 30 seconds The results are shown in Table 3. Example 3 Painting was carried out in the same manner as in Example 2, except that the blower had a built-in heater and 60°C air was blown. The results are shown in Table-3. Comparative Example 1 Coating was carried out in the same manner as in Example 1, except that the object to be coated was pulled up and air was blown 80 seconds later.
The results are shown in Table-3. Comparative Example 2 Coating was carried out in the same manner as in Example 1, except that air was blown on the immersion coating tank 10 cm from the paint liquid level. The results are shown in Table-3. Comparative Example 3 Painting was carried out in the same manner as in Example 1 except that the wind speed was 2 m/sec. The results are shown in Table-3. Comparative Example 4 Painting was carried out in the same manner as in Example 1 except that the wind speed was 55 m/sec. The results are shown in Table-3. In addition, since one compressor did not have enough capacity, it was necessary to install two compressors in series. Comparative Example 5 Painting was carried out in the same manner as in Example 1 except that the nozzle diameter was 0.05 mm. Table 3 shows the results.
Shown below. Comparative example 6 In Example 1, the nozzle diameter was 12 mm, and the wind speed was
Painting was carried out in the same manner as in Example 1, except that the air velocity was 4.5 m/sec (even if the air volume was maximized, a higher wind speed could not be obtained). The results are shown in Table-3. Comparative Example 7 Coating was carried out in the same manner as in Example 2 except that the slit width was 0.03 mm. Table 3 shows the results.
Shown below. Comparative Example 8 Coating was carried out in the same manner as in Example 2 except that the slit width was 4 mm and the distance between the slit opening and the object to be coated was 8 cm. The results are shown in Table-3. Comparative Example 9 In Example 2, 0.05% of antifoaming agent (trade name "Formaster V", manufactured by Nopko Chemical Co., Ltd.) was added to paint No. 2.
Coating was carried out in the same manner as in Example 2, except that a paint containing 10% of the total amount was used, and no air was blown after lifting. The results are shown in Table-3. As is clear from Table 3, Examples 1, 2, and 3, which were coated according to the present invention, had good coating film condition, paint condition in the bath, coating condition, etc. On the other hand, as in Comparative Example 1, when the air blowing time was late, the coating film at the bottom of the hole had sagging and sagging, and there were sag in the horizontal part, and a homogeneous coating film could not be obtained. Furthermore, as in Comparative Example 2, when air was blown close to the paint liquid surface, the paint in the bath thickened. The next day, when the same coating treatment was carried out in the same dip coating tank, the condition of the coating film was poor. Further, when the wind speed was low as in Comparative Example 3, the coating film condition was poor as in Comparative Example 1. In addition, when the wind velocity was high as in Comparative Example 4, the object to be coated was shaken greatly, the coating workability was poor, more power was required than necessary, and the paint in the bath increased in viscosity. Also, in Comparative Examples 5 and 7, which had small nozzle diameters and slit widths, the coating film condition was poor as in Comparative Example 1. Further, in Comparative Examples 6 and 8, which had a large nozzle diameter and a large slit width, the object to be coated shook greatly and the coating workability was poor, and extra power was required. In addition, as in Comparative Example 9, in which an antifoaming agent was added, lumps remained in the horizontal portions, and salt water spray resistance was poor. Furthermore, when paints Nos. 3 to 12 in Table 2 were painted in the same manner as in Example 1, paints Nos. 9, 10, and 12 had poor dry coating smoothness, and paints Nos. 11 and 12 had poor smoothness.
The same results as in Example 1 were obtained except that aggregates were generated in the paint in the bath.

【table】 [Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of the dip coating apparatus of the present invention, and FIG. 2 shows the relationship between the flow direction of the object to be coated (conveyor) and the flow direction of air.
Arrow _F1 in FIG. 2 indicates the flow direction of the object to be coated (conveyor). 1: Dip coating tank, 2: Object to be coated, 3: Conveyor,
4, 4': Nozzle.

Claims (1)

[Scope of Claims] 1. In a method of painting by dipping an object to be coated in a dip coating tank containing a slurry-like paint, within at least one minute after lifting the object from the dip coating tank, A dip coating method for slurry paint, which is characterized by exposing objects to air at a wind speed of 3 to 50 m/sec. 2 Inject air through a nozzle with a nozzle diameter of 0.1 to 10 mm or a slit with a slit width of 0.05 to 3 mm,
2. A method for dip coating a slurry-like paint according to claim 1, characterized in that the object to be coated is exposed to air. 3. A method for dip coating a slurry paint according to claim 1, which comprises applying heated air of 100° C. or less to the object to be coated. 4. The dip coating method for slurry paint according to claim 1, characterized in that air is applied to the object to be coated at a position above the dip coating tank and at least 15 cm above the paint liquid level. 5 A slurry paint is made of (A) (a) an epoxy resin with an average molecular weight of 900 to 3000 obtained by the reaction of bisphenol A and epichlorohydrin and/or methyl epichlorohydrin, dicyandiamide, a blocked isocyanate compound, and an acid value of 40 to 250. A composition consisting of 30 to 55 weight percent of resin particles with an average particle size of 10 to 80 μ and (b) 70 to 45 percent water by weight, consisting of at least one type of curing agent selected from the group consisting of polyester resins... 100 weight percent Part (B) Polyethylene oxide and/or bentonite with an average molecular weight of 300,000 to 4 million...0.05 to 0.6
Parts by weight, and (C) Nonionic surfactant with HLB value 12 to 16...0.1
The dip coating method for a slurry-like paint according to claim 1, characterized in that the amount is 0.5 parts by weight. 6. The dip coating method for a slurry paint according to claim 5, wherein the bentonite has a viscosity of 5 centipoise or more at 20°C when made into a 3% by weight aqueous dispersion.