A dry powder paint for casting and a method for producing the same

Abstract

The present application relates to the technical field of foundry coating, and provides a dry powder coating for casting, which comprises, in parts by mass, 100 parts of refractory aggregate, 0.4-1.2 parts of film forming aid, 0.1-4 parts of binder, 0.01-1 part of wetting agent, 0.01-5 parts of dispersing agent, 0.01-1 part of defoaming agent, and 1-4.5 parts of suspending agent; wherein the refractory aggregate is one or more of forsterite, graphite, mica powder and talc powder; the present application has good comprehensive performance, and the 24h suspending property, coating wear resistance, high-temperature exposure crack level and shear thinning index of the coating meet the use requirements and are superior to the existing indexes; meanwhile, the present application overcomes the problems of sand sticking and coating wall sticking after use of the existing dry powder coating; the present application increases the convenience of coating transportation and reduces the coating transportation cost, and improves the storage safety of the coating without fire risk.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foundry coating, more particularly to a powder alcohol-based foundry coating. BACKGROUND

[0002] At present, the foundry coating is mainly supplied in the form of finished slurry coating, which usually contains about 50% carrier liquid. For alcohol-based coating, it contains up to 40% methanol. Therefore, the slurry coating has the problem of inconvenient transportation for the supplier, and the use cost of the coating is increased for the user due to the increase of the transportation cost of the coating, and there is a certain safety risk for the user. Therefore, the supply mode of the slurry coating has certain disadvantages for the supplier and the user. If the dry powder coating is supplied, the problem of inconvenient transportation can be solved, and the transportation cost of the coating can be greatly reduced to reduce the use cost of the coating in foundry, and there is no flammable material for storage, and the safety is greatly improved. However, the existing dry powder coating on the market has a certain gap in the comprehensive performance index with the slurry foundry coating due to the imperfect formula technology. SUMMARY

[0003] The present application provides a powder foundry coating to solve the problems of inconvenient transportation of the slurry coating, high use cost of the coating and poor comprehensive performance index of the dry powder coating in the prior art. The dry powder coating has good comprehensive performance, and the 24h suspension, coating wear resistance, high temperature exposure crack level and shear thinning index meet the use requirements and are better than the existing index. At the same time, the problems of sticking sand and coating wall sticking after using the existing dry powder coating are overcome. The coating of the present application increases the convenience of coating transportation and reduces the transportation cost of the coating, improves the storage safety of the coating, has no risk of fire, and can directly use the purchased methanol to mix with the coating for use.

[0004] To achieve the purpose, the present application provides the following technical scheme:

[0005] A dry powder coating for foundry, by mass fraction, comprises refractory aggregate 100 parts, film forming aid 0.4-1.2 parts, binder 0.1-4 parts, wetting agent 0.01-1 parts, dispersing agent 0.01-5 parts, defoaming agent 0.01-1 parts, and suspending agent 1-4.5 parts. The refractory aggregate is one or more of forsterite, graphite, mica powder and talc powder.

[0006] In one embodiment, the MgO content of the forsterite is greater than or equal to 44%, and the SiO2 content is greater than or equal to 42%; the Al2O3 content of the mica powder is greater than or equal to 35%, and the SiO2 content is greater than or equal to 49%.

[0007] In one of the embodiments, the film forming aids are one or more of alcohol ester twelve, diisobutyl nylonic acid ester, ethylene glycol phenyl ether.

[0008] In one of the embodiments, the binders are one or more of acrylic modified polyester resin, hydroxy acrylic resin, urethane resin, esterified rosin, phenol formaldehyde resin.

[0009] In one of the embodiments, the wetting agents are one or more of sodium dodecyl benzene sulfonate, dodecynediol polyoxyethylene ether, ethylene diamine polyoxyethylene polyoxypropylene ether, stearyl alcohol polyoxypropylene ether.

[0010] In one of the embodiments, the dispersants are one or more of methylene bis naphthalene sulfonic acid sodium, polyethylene wax, maleic acid acrylic copolymer.

[0011] In one of the embodiments, the defoaming agents are one or more of fatty acid diethanol amide, sodium hexadecyl benzene sulfonate, octyl phenol polyoxyethylene ether.

[0012] In one of the embodiments, the suspending agents are one or more of attapulgite, lithium bentonite, organic bentonite, cellulose, polyvinyl butyral.

[0013] The application also provides a preparation method of the dry powder coating for casting, characterized by comprising the following steps:

[0014] S1: grinding the blocky materials in the components into powders;

[0015] S2: sequentially feeding the suspending agents, the binders and the film forming aids into a spiral mixer and mixing for 10-30 minutes;

[0016] S3: sequentially feeding the mixed materials, the wetting agents, the dispersants, the defoaming agents and the refractory aggregates into the spiral mixer and mixing for 20-30 minutes until uniform, and then discharging and packaging.

[0017] The application also provides a use method of the dry powder coating for casting, characterized by adding methanol into a stirring tank, then starting a mechanical stirring motor, slowly feeding the dry powder coating for casting, and continuously stirring for 0.5-1.5 hours until use, wherein the weight ratio of the methanol to the dry powder coating for casting is 1:1-1:2, and the stirring speed is greater than or equal to 100 revolutions per minute.

[0018] The application has the following advantages:

[0019] The application provides a dry powder coating for casting, and the powder coating formula of the application does not contain liquid components, is convenient to transport, and reduces the coating transportation cost by about 40-50%, thereby effectively reducing the coating use cost of a casting factory; the application changes the component ratio of refractory aggregates, and a small amount of refractory aggregate with good sintering property is added in the selection of the refractory aggregate, so that the coating has good high-temperature strength and is not easy to stick sand, and the sticking sand problem caused by the coating in the prior art after casting is overcome; meanwhile, the selected refractory aggregate and the selected film-forming aid effectively ensure the refractory strength and good sintering property, the film-forming aid uses nylon acid diisobutyl ester and dodecynediol polyoxyethylene ether, the coating has good leveling property and is smooth to brush; the application introduces a low-temperature binder, and the introduction of the acrylic acid modified polyester resin makes the coating have high low-temperature strength, is not easy to drop powder when being hand-wound, has small brush marks on the coating surface, and has better application effect.

[0020] The powder alcohol-based coating has good comprehensive performance, and the indexes of 24h suspensibility, coating wear resistance, high-temperature exposure heat crack grade and shear thinning index are all better than those of the dry powder coating in the prior art. In addition, the surface tension of the finished slurry coating prepared from the dry powder coating of the application is low, and the sand mold surface can be better wetted, which is favorable for the application of the coating. The powder alcohol-based coating of the application is mixed with dry powder coating and methanol on site before use, and can be normally used after being uniformly mechanically stirred, so that the coating can be prepared on site and used, and the on-site coating use management is facilitated. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the application, the application will be described more fully below.

[0022] Case 1

[0023] The application provides a dry powder coating for casting, and the powder coating formula of the application does not contain liquid components, is convenient to transport, and reduces the coating transportation cost by about 40-50%, thereby effectively reducing the coating use cost of a casting factory; the application changes the component ratio of refractory aggregates, and a small amount of refractory aggregate with good sintering property is added in the selection of the refractory aggregate, so that the coating has good high-temperature strength and is not easy to stick sand, and the sticking sand problem caused by the coating in the prior art after casting is overcome; meanwhile, the selected refractory aggregate and the selected film-forming aid effectively ensure the refractory strength and good sintering property, the film-forming aid uses nylon acid diisobutyl ester and dodecynediol polyoxyethylene ether, the coating has good leveling property and is smooth to brush; the application introduces a low-temperature binder, and the introduction of the acrylic acid modified polyester resin makes the coating have high low-temperature strength, is not easy to drop powder when being hand-wound, has small brush marks on the coating surface, and has better application effect.

[0024] The refractory aggregate includes 400Kg of magnesium olivine, 300Kg of graphite and 300Kg of mica powder.

[0025] The MgO content of the magnesium olivine is 46%, and the SiO2 content is 44%; the Al2O3 content of the mica powder is 35%, and the SiO2 content is 52%.

[0026] The film-forming aid is 2Kg of nylon acid isobutyl ester and 8Kg of ethylene glycol phenyl ether.

[0027] The binder is 10Kg of acrylic acid modified polydiester resin, 20Kg of esterified rosin and 5Kg of hydroxy acrylic acid resin and 5Kg of phenolic resin.

[0028] Wetting agent: dodeca acetylene glycol polyoxyethylene ether 5Kg, ethylenediamine polyoxyethylene polyoxypropylene ether 4Kg;

[0029] Dispersant: methylene bis naphthalene sulfonic acid sodium 1Kg, polyethylene wax 4Kg;

[0030] Defoaming agent: octyl phenol polyoxyethylene ether 2Kg;

[0031] Suspending agent: polyvinyl butyral 5Kg, attapulgite 20Kg.

[0032] The application provides a preparation method:

[0033] S1: grinding the acrylic modified polyester resin and the esterified rosin into powder;

[0034] S2: putting the poly-suspending agent polyvinyl butyral 5Kg, attapulgite 20Kg, and the binder acrylic modified polyester resin 10Kg, esterified rosin 20Kg, hydroxy acrylic resin 5Kg, phenolic resin 5Kg, and film forming aid nylon acid diisobutyl ester 2Kg, ethylene glycol phenyl ether 8Kg into a spiral mixer, and mixing for 20 minutes;

[0035] S3: putting the mixed materials in step S2, the wetting agent dodeca acetylene glycol polyoxyethylene ether 5Kg, the ethylenediamine polyoxyethylene polyoxypropylene ether 4Kg, the dispersant methylene bis naphthalene sulfonic acid sodium 1Kg, the polyethylene wax 4Kg, the defoaming agent octyl phenol polyoxyethylene ether 2Kg, the refractory aggregate peridot 400Kg, the graphite 300Kg, and the mica powder 300Kg into a spiral mixer in sequence, mixing for 10 minutes, and then discharging and packaging.

[0036] The use method of the dry powder paint for casting in the embodiment is as follows: 50Kg of methanol is added into a mechanical stirring tank, then a mechanical stirring motor is started, 50Kg of the dry powder paint for casting is slowly put in, and continuous stirring is carried out for 1 hour to obtain a finished product alcohol-based paint; wherein the stirring speed is 100 revolutions per minute.

[0037] Embodiment two:

[0038] The application provides a dry powder paint for casting, which comprises, in parts by mass, refractory aggregate 100 parts, film forming aid 1 part, binder 3 parts, wetting agent 0.9 parts, dispersant 0.4 parts, defoaming agent 0.25 parts, and suspending agent 2 parts.

[0039] The refractory aggregate comprises peridot 400Kg, graphite 200Kg, and talc powder 400Kg.

[0040] The MgO content in the peridot is 44%, and the SiO2 content is 42%; the Al2O3 content in the mica powder is 35%, and the SiO2 content is 49%;

[0041] Film forming aid is: diisobutyl nylonic acid 2Kg, ethylene glycol phenyl ether 8Kg;

[0042] Binder: acrylic modified polyester resin 10Kg, esterified rosin 10Kg, hydroxy acrylic resin 5Kg, phenolic resin 5Kg;

[0043] Wetting agent: dodecynediol polyoxyethylene ether 5Kg, ethylenediamine polyoxyethylene polyoxypropylene ether 4Kg;

[0044] Dispersant: methylene bis naphthalene sulfonic acid sodium 1Kg, maleic acid acrylic copolymer 3Kg;

[0045] Defoaming agent is: octylphenol polyoxyethylene ether 2.5Kg;

[0046] Suspending agent: polyvinyl butyral 5Kg, cellulose 15Kg.

[0047] The application provides a preparation method:

[0048] S1: grinding acrylic modified polyester resin and esterified rosin into powder;

[0049] S2: put poly-suspending agent polyvinyl butyral 5Kg, cellulose 15Kg, binder acrylic modified polyester resin 10Kg, esterified rosin 10Kg, hydroxy acrylic resin 5Kg, phenolic resin 5Kg, film forming aid diisobutyl nylonic acid 2Kg, ethylene glycol phenyl ether 8Kg into a spiral mixer, and mix for 20min;

[0050] S3: put the mixed materials in step S2, wetting agent dodecynediol polyoxyethylene ether 5Kg, ethylenediamine polyoxyethylene polyoxypropylene ether 4Kg, dispersant methylene bis naphthalene sulfonic acid sodium 1Kg, maleic acid acrylic copolymer 3Kg, defoaming agent octylphenol polyoxyethylene ether 2Kg, refractory aggregate peridot 400Kg, graphite 200Kg, talc powder 400Kg into a spiral mixer in sequence, mix for 10min, and then discharge and package.

[0051] The use method of the dry powder paint for casting in the embodiment is as follows: 50Kg of methanol is added into a mechanical stirring tank, then a mechanical stirring motor is started, 100Kg of the dry powder paint for casting is slowly put in, and continuous stirring is carried out for 1h to obtain a finished product alcohol-based paint; wherein, the stirring speed is 150r / min.

[0052] Embodiment three:

[0053] The embodiment of the application provides a dry powder paint for casting, which comprises, in parts by mass, refractory aggregate 100 parts, film forming aid 1.1 parts, binder 3.5 parts, wetting agent 0.8 parts, dispersant 0.4 parts, defoaming agent 0.25 parts, and suspending agent 3 parts.

[0054] The refractory aggregate comprises 400 Kg of forsterite, 300 Kg of mica powder and 300 Kg of talc powder;

[0055] The MgO content of the forsterite is 47%, and the SiO2 content is 43%; the Al2O3 content of the mica powder is 36%, and the SiO2 content is 49%;

[0056] The film forming aid comprises 5 Kg of diisobutyl naphthalene acid and 6 Kg of pure ester twelve;

[0057] The binder comprises 15 Kg of acrylic modified polyester resin, 10 Kg of esterified rosin, 5 Kg of hydroxy acrylic resin and 5 Kg of urethane resin;

[0058] The wetting agent comprises 4 Kg of dodecynediol polyoxyethylene ether and 4 Kg of stearyl alcohol polyoxypropylene ether;

[0059] The dispersing agent comprises 2 Kg of methylene bis naphthalene sulfonic acid sodium and 2 Kg of polyethylene wax;

[0060] The defoaming agent is 2.5 Kg of fatty acid diethanol amide;

[0061] The suspending agent comprises 5 Kg of polyvinyl butyral and 25 Kg of organic bentonite.

[0062] The application provides a preparation method:

[0063] S1: grinding the acrylic modified polyester resin and the esterified rosin into powder;

[0064] S2: putting the poly-suspending agent (5 Kg of polyvinyl butyral and 25 Kg of organic bentonite), the binder (15 Kg of acrylic modified polyester resin, 10 Kg of esterified rosin, 5 Kg of hydroxy acrylic resin and 5 Kg of urethane resin), the film forming aid (5 Kg of diisobutyl naphthalene acid and 6 Kg of pure ester twelve) into a spiral mixer and mixing for 20 min;

[0065] S3: putting the mixed materials in step S2, the wetting agent (5 Kg of dodecynediol polyoxyethylene ether and 4 Kg of ethylenediamine polyoxyethylene polyoxypropylene ether), the dispersing agent (1 Kg of methylene bis naphthalene sulfonic acid sodium and 4 Kg of polyethylene wax), the defoaming agent (2.5 Kg of fatty acid diethanol amide), the refractory aggregate (400 Kg of forsterite, 200 Kg of graphite and 400 Kg of talc powder) into a spiral mixer in sequence, mixing for 10 min and then discharging and packaging.

[0066] The use method of the dry powder paint for casting in the embodiment is as follows: 50 Kg of methanol is added into a mechanical stirring tank, then a mechanical stirring motor is started, 100 Kg of the dry powder paint for casting is slowly put in and stirring is continuously conducted for 1 hour to obtain a finished product alcohol-based paint; wherein the stirring speed is 100 revolutions per minute.

[0067] Embodiment four:

[0068] The embodiment of the present application provides a dry powder paint for casting, which comprises, in parts by mass, refractory aggregate 100 parts, film forming aid 1.2 parts, binder 4 parts, wetting agent 0.7 parts, dispersant 0.5 parts, defoaming agent 0.25 parts, and suspending agent 4 parts.

[0069] The refractory aggregate comprises mica powder 300 Kg, graphite 200 Kg, and talc powder 500 Kg.

[0070] The MgO content of the forsterite is 46%, and the SiO2 content is 42%; the Al2O3 content of the mica powder is 36%, and the SiO2 content is 49%.

[0071] The film forming aid is diisobutyl nylonic acid 5 Kg and ethylene glycol phenyl ether 7 Kg.

[0072] The binder is acrylic modified polyester resin 5 Kg, esterified rosin 30 Kg, and hydroxy acrylic resin 5 Kg.

[0073] The wetting agent is dodecaacetylene glycol polyoxyethylene ether 3 Kg and ethylenediamine polyoxyethylene polyoxypropylene ether 4 Kg.

[0074] The dispersant is methylene bis naphthalene sulfonic acid sodium 2 Kg and polyethylene wax 3 Kg.

[0075] The defoaming agent is fatty acid diethanol amide 2.5 Kg.

[0076] The suspending agent is cellulose 15 Kg and organic bentonite 25 Kg.

[0077] The present application provides a preparation method.

[0078] S1: grinding acrylic modified polyester resin and esterified rosin into powder;

[0079] S2: putting the suspending agent cellulose 15 Kg and organic bentonite 25 Kg, the binder acrylic modified polyester resin 5 Kg, esterified rosin 30 Kg, and hydroxy acrylic resin 5 Kg, the film forming aid diisobutyl nylonic acid 5 Kg and ethylene glycol phenyl ether 7 Kg into a spiral mixer, and mixing for 20 min;

[0080] S3: putting the mixed materials in step S2, the wetting agent dodecaacetylene glycol polyoxyethylene ether 3 Kg and ethylenediamine polyoxyethylene polyoxypropylene ether 4 Kg, the dispersant methylene bis naphthalene sulfonic acid sodium 2 Kg and polyethylene wax 3 Kg, the defoaming agent fatty acid diethanol amide 2.5 Kg, and the refractory aggregate mica powder 300 Kg, graphite 200 Kg, and talc powder 500 Kg into a spiral mixer in sequence, mixing for 10 min, and then discharging and packaging.

[0081] The use method of the dry powder coating for casting in this embodiment is as follows: 50Kg of methanol is added into a mechanical stirring tank, then the mechanical stirring motor is started, 100Kg of the dry powder coating for casting is slowly added, and stirring is continuously carried out for 1 hour to obtain the finished product alcohol-based coating; wherein the stirring speed is 150r / min.

[0082] Case five:

[0083] The embodiment of the present application provides a dry powder coating for casting, which comprises, in parts by mass, 100 parts of refractory aggregate, 1 part of film forming aid, 3 parts of binder, 0.6 parts of wetting agent, 0.8 parts of dispersing agent, 0.25 parts of defoaming agent, and 3.5 parts of suspending agent.

[0084] The refractory aggregate comprises 400Kg of mica powder, 300Kg of forsterite, and 300Kg of talc powder.

[0085] The content of MgO in the forsterite is 47%, and the content of SiO2 is 43%; the content of Al2O3 in the mica powder is 36%, and the content of SiO2 is 49%.

[0086] The film forming aid comprises 4Kg of diisobutyl nylonic acid ester, 3Kg of alcohol ester twelve, and 3Kg of ethylene glycol phenyl ether.

[0087] The binder comprises 15Kg of acrylic modified polyester resin, 10Kg of esterified rosin, and 5Kg of phenolic resin.

[0088] The wetting agent comprises 3kg of dodecynediol polyoxyethylene ether and 3kg of stearyl alcohol polyoxypropylene ether.

[0089] The dispersing agent comprises 4Kg of methylene bis naphthalene sulfonic acid sodium and 4Kg of maleic acid acrylic copolymer.

[0090] The defoaming agent comprises 1.5Kg of fatty acid diethanol amide and 1Kg of fatty acid diethanol amide.

[0091] The suspending agent comprises 35Kg of cellulose.

[0092] The present application provides a preparation method:

[0093] S1: grinding the acrylic modified polyester resin and the esterified rosin into powder;

[0094] S2: putting 35Kg of the suspending agent cellulose, 15Kg of the binder acrylic modified polyester resin, 10Kg of the esterified rosin, 5Kg of the phenolic resin, 4Kg of the film forming aid diisobutyl nylonic acid ester, 3Kg of the alcohol ester twelve, and 3Kg of the ethylene glycol phenyl ether into a spiral mixer, and mixing for 20min;

[0095] S3: The mixed materials in step S2, wetting agent dodecynediol polyoxyethylene ether 3Kg, stearyl alcohol polyoxypropylene ether 3Kg, dispersant methylene bis naphthalene sulfonic acid sodium 4Kg, maleic acid acrylic copolymer 4Kg, defoaming agent fatty acid diethanolamide 1.5Kg, fatty acid diethanolamide 1Kg, refractory aggregate mica powder 400Kg, forsterite 300Kg, talc powder 300Kg, were sequentially put into a spiral mixer and mixed for 10 minutes before discharging and packaging.

[0096] The use method of the dry powder coating for casting in this embodiment is as follows: 50Kg of methanol was added into a mechanical stirring tank, then the mechanical stirring motor was started, 50Kg of the dry powder coating for casting was slowly put in, and continuous stirring was carried out for 1 hour to obtain the finished product alcohol-based coating; wherein the stirring speed was 100r / min.

[0097] In the above five embodiments, the prepared dry powder coating for casting was mixed with methanol at a specified weight ratio and mechanically stirred to obtain the finished product alcohol-based coating for detection. Then, the performance indicators of the finished product slurry alcohol-based coating were determined according to the method in the standard JB / T9226-2008, and the shear thinning index (the ratio of the apparent viscosity at 6r / min to the apparent viscosity at 60r / min) and the supernatant surface tension data of the coating were tested. The data results are shown in Table 1 below. In addition, Comparative Example 1 is a dry powder coating on the market, and Comparative Example 2 is a slurry alcohol-based coating on the market.

[0098] Table 1: Example data comparison

[0099]

[0100]

[0101] From the data in Table 1, it can be seen that the performance of the finished product slurry coating prepared by the dry powder coating of Example 1-Example 5 is better than that of the market dry powder coating of Comparative Example 1 and the alcohol-based slurry coating of Comparative Example 2 in terms of 24h suspensibility, coating wear resistance, high temperature exposure crack grade, shear thinning index and other indicators. In addition, the surface tension of the finished product coating prepared by the dry powder coating of Example 1-Example 5 is lower, which can better wet the surface of the sand mold, which is beneficial for the application of the coating.

Claims

1. A method of using a dry powder paint for casting, characterized in that, The stirring tank is added with methanol, then a mechanical stirring motor is started, and the dry powder coating for casting is slowly added, and stirring is continuously carried out for 0.5-1.5 hours, and then the dry powder coating for casting can be used, wherein the weight ratio of the methanol to the dry powder coating for casting is 1:1-1:

2. The dry powder coating for casting comprises, in parts by mass, 100 parts of refractory aggregate, 0.4-1.2 parts of film-forming aid, 0.1-4 parts of binder, 0.01-1 part of wetting agent, 0.01-5 parts of dispersing agent, 0.01-1 part of defoaming agent, and 1-4.5 parts of suspending agent. The refractory aggregate is at least three of forsterite, graphite, mica powder and talc powder. The film-forming aid is diisobutyl naphthalene acid and alcohol ester twelve, or diisobutyl naphthalene acid and ethylene glycol phenyl ether, or diisobutyl naphthalene acid, alcohol ester twelve and ethylene glycol phenyl ether. The wetting agent is dodecynediol polyoxyethylene ether and ethylenediamine polyoxyethylene polyoxypropylene ether, or dodecynediol polyoxyethylene ether and stearyl alcohol polyoxypropylene ether. The binder is one or several of acrylic acid modified polyester resin, hydroxy acrylic acid resin, urethane resin, esterified rosin and phenolic resin. The preparation method of the dry powder coating for casting comprises the following steps: S1: grinding the blocky materials in the components into powder; S2: sequentially adding the suspending agent, the binder and the film-forming aid into a spiral mixer, and mixing for 10-30 minutes; S3: sequentially adding the mixed materials after mixing, the wetting agent, the dispersing agent, the defoaming agent and the refractory aggregate into a spiral mixer, and mixing for 20-30 minutes until uniform, and then discharging and packaging.

2. A method of using a dry powder paint for casting according to claim 1, characterized in that, The MgO content of the forsterite is ≥44%, and the SiO2 content is ≥42%; the Al2O3 content of the mica powder is ≥35%, and the SiO2 content is ≥49%.

3. A method of using a dry powder paint for casting according to claim 1, characterized in that, The dispersing agent is one or several of methylene bis naphthalene sulfonic acid sodium, polyethylene wax and maleic acid acrylic acid copolymer.

4. A method of using a dry powder paint for casting according to claim 1, characterized in that, The defoaming agent is one or several of fatty acid diethanol amide, sodium hexadecyl benzene sulfonate and octyl phenol polyoxyethylene ether.

5. The method of using a dry powder paint for casting according to claim 1, wherein, The suspending agent is one or several of attapulgite, lithium-based bentonite, organic bentonite, cellulose and polyvinyl butyral.

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