A kind of preparation method of dispellable mould casting water based paint
Technical field
The present invention relates to casting field, particularly a kind of lost foam casting coating field.
Background technology
Lost foam casting is described as " green foundry engieering " and " foundry engieering of 21 century " with its unique advantage.From the sixties in last century since China begins to use, through the continuous development of decades, the application of lost foam casting constantly enlarges, and has obtained good economic benefit and social benefit.
Lost foam casting coating is one of two big key technologies of lost foam casting process.The performance of coating directly influences the quality of foundry goods, has significantly different with cast paint with traditional sand mold.The main purpose of tradition sand casting coating is to prevent that foundry goods from producing penetration and chemical scab; And coating for dispellable mould casting is except that above-mentioned two effects; The important function that also has formation and maintenance foundry goods cavity, so it must have higher normal temperature strength, elevated temperature strength and suitable hot permeability.
Though lost foam casting process has comparatively fast been developed since coming out, coating technology is perplexing casting yield always and is being difficult to bigger raising, and its main cause is because the quality of coating can not satisfy the requirement of lost foam casting process.The one, normal temperature strength does not reach requirement, causes apperance distortion and coating breakage that foundry goods is scrapped during moulding; The 2nd, elevated temperature strength is lower, occurs during cast that the foundry goods die cavity subsides, destruction, coating are peeled off etc. that foundry goods is scrapped; The 3rd, coating does not have suitable hot permeability, and too high gas permeability causes die cavity to subside, and low excessively gas permeability makes foundry goods produce casting flaws such as pore, elephant skin, slag inclusion.
Summary of the invention
Deficiency to prior art; One of the object of the invention is to provide a kind of preparation method of dispellable mould casting water based paint; Make coating elevated temperature strength and low temperature intensity and other performance through this method preparation all satisfy the lost foam casting instructions for use, and technology is simple, with low cost.
For realizing above-mentioned purpose, the technical scheme that the present invention adopts is:
A kind of preparation method of dispellable mould casting water based paint, this method comprises the steps:
1) weigh batching:
Weighing following substances by weight percentage; 150-200 order mullite powder 15-18%, 80-150 order silica flour 5-8%, 200-320 order bauxite 12-18%, Ludox 1.2-1.5%, polyvinyl acetate breast 1.5-3.0%; Carboxymethyl cellulose acid sodium 0.1-0.4%, sodium alkyl benzene sulfonate 0.15-0.35%, sodium sulphate 0.15-0.35%, n-octyl alcohol 0.1-0.3%, AEO 0.10-0.18%, surplus is a water;
2) coating preparation:
A. mullite powder, silica flour and bauxite base-material are stirred in the coating grinding equipment, the water of 30-40% that adds Total Water then is in base-material, and base-material is moistening and stir and open;
B. Ludox, polyvinyl acetate breast, the sour sodium of carboxymethyl cellulose, sodium alkyl benzene sulfonate, sodium sulphate, n-octyl alcohol, AEO are added successively above-mentioned moisteningly and stir in the base-material open, and the water that adds the 5-10% of Total Water stirs 30-60min in the coating grinding equipment.
C. then with the water of surplus in the coating grinding equipment, and grind 120-180min and get final product.
Select for use in base-material with the mullite powder serve as the master be because the fusing point of mullite powder up to 1800 ℃, heat resistance is good, mullite powder coefficient of thermal expansion is low; Use the mullite powder to make base-material, coating low temperature and elevated temperature strength are good, and thermal conductivity might as well; And mullite powder heat storage coefficient is high; Help accelerating the cooling of foundry goods, refinement foundry goods working lining tissue also increases the chill degree of depth of foundry goods working lining, helps improving foundry goods service life.Also add silica flour and bauxite in addition, the silica flour fusing point reaches 1713 ℃, and silica flour density 2700kg/m
3, the bauxite fusing point adds the suspendability that an amount of silica flour and bauxite can improve coating greater than 1770 ℃ in the base-material.The dispellable mould casting water based paint adopts 150-200 order mullite powder 15-18%, 80-150 order silica flour 5-8%, 200-320 order bauxite 12-18% as aggregate, has good low temperature and elevated temperature strength performance, helps obtaining high-quality cast product.Do not add graphite powder, talcum powder and diatomite in the base-material; Do not add graphite and help environmental protection; And contain the crystallization water in talcum powder and the diatomite; Under the effect of high-temperature metal liquation, be prone to decomposition and discharge the crystallization water and form steam immersion molten metal, be prone in foundry goods, form casting flaws such as pore after solidifying.
Coating of the present invention is main binding agent with Ludox, polyvinyl acetate breast carboxylic and methyl Carboxymethylcellulose sodium, has both had high temperature adhesive, has low temperature adhesive again.The substitution value of the carboxymethyl cellulose acid sodium that the present invention selected for use is 0.65-0.85, polymerization degree n>200.The main effect of carboxymethyl cellulose acid sodium in coating has: the one, form netted stereochemical structure by macromolecular chain; The 2nd, the macromolecular chain adsorbed water molecule forms solvated layer; The 3rd, have the shear thinning effect.After adding carboxymethyl cellulose acid sodium in the coating, form the multiviscosisty phenomenon, the paint adhesion effect is improved.
In order to improve the suspendability of coating, the present invention adds sodium alkyl benzene sulfonate and sodium sulphate.
Be prone to foam in the coating,, in coating, add n-octyl alcohol, not only have good froth breaking effect, also have the effect that improves the coating wetability if untimely removal will influence the dope layer surface quality, and then influence casting quality.
In order to improve the wettability of coating, prevent dope layer cracking and peel off, in coating, add AEO and make surfactant, can obviously improve the combination property of dope layer, be very favourable to improving casting quality.
The present invention with water as carrier, have with low cost, preservation, transportation and characteristics such as easy to use.
The beneficial effect of the inventive method is:
Method of the present invention makes coating and has excellent performance, has good suspension and thixotropy; Coating also has air permeability and good and higher surface strength, has well satisfied the requirement of coating for dispellable mould casting.This coating compound method is simple, nonhazardous, and the cast(ing) surface of production is highly polished.This coating is mainly used in lost foam casting and produces cast iron, cast steel and non-ferrous alloy casting.Compare with external like product, under the suitable situation of quality, required cost reduces by 50%.The present invention has overcome that refractory powder costs an arm and a leg the defective that the coating material production cost is higher in the existing routine casting coating technology of preparing; While cast paint of the present invention is smooth and viscosity suitable.And just can produce the high-quality cast paint with cheap raw material and simple production technology, effectively reduce the coating material production cost, and quality of finished product good.
Below in conjunction with embodiment the present invention is made further detailed description:
The specific embodiment
Embodiment one
A kind of preparation method of dispellable mould casting water based paint, this method comprises the steps:
1) weigh batching:
Weighing following substances by weight percentage; 150-200 order mullite powder 18%, 80-150 order silica flour 6%, 200-320 order bauxite 15%, Ludox 1.2%, polyvinyl acetate breast 2.5%; Carboxymethyl cellulose acid sodium 0.3%, sodium alkyl benzene sulfonate 0.2%, sodium sulphate 0.2%, n-octyl alcohol 0.2%, AEO 0.15%, surplus is a water;
2) coating preparation:
A. mullite powder, silica flour and bauxite base-material are stirred in the coating grinding equipment, 30% the water that adds Total Water then is in base-material, and base-material is moistening and stir and open;
B. Ludox, polyvinyl acetate breast, the sour sodium of carboxymethyl cellulose, sodium alkyl benzene sulfonate, sodium sulphate, n-octyl alcohol, AEO are added successively above-mentioned moisteningly and stir in the base-material open, and 10% the water that adds Total Water stirs 30min in the coating grinding equipment;
C. then with 60% water of Total Water in the coating grinding equipment, and grind 120min and get final product.
Embodiment two
A kind of preparation method of dispellable mould casting water based paint, this method comprises the steps:
1) weigh batching:
Weighing following substances by weight percentage; 150-200 order mullite powder 18%, 80-150 order silica flour 6%, 200-320 order bauxite 15%, Ludox 1.2%, polyvinyl acetate breast 2.5%; Carboxymethyl cellulose acid sodium 0.3%, sodium alkyl benzene sulfonate 0.2%, sodium sulphate 0.2%, n-octyl alcohol 0.2%, AEO 0.15%, surplus is a water;
2) coating preparation:
A. mullite powder, silica flour and bauxite base-material are stirred in the coating grinding equipment, 35% the water that adds Total Water then is in base-material, and base-material is moistening and stir and open;
B. Ludox, polyvinyl acetate breast, the sour sodium of carboxymethyl cellulose, sodium alkyl benzene sulfonate, sodium sulphate, n-octyl alcohol, AEO are added successively above-mentioned moisteningly and stir in the base-material open, and 8% the water that adds Total Water stirs 45min in the coating grinding equipment;
C. then with 57% water of Total Water in the coating grinding equipment, and grind 150min and get final product.
Embodiment three
A kind of preparation method of dispellable mould casting water based paint, this method comprises the steps:
1) weigh batching:
Weighing following substances by weight percentage; 150-200 order mullite powder 18%, 80-150 order silica flour 6%, 200-320 order bauxite 15%, Ludox 1.2%, polyvinyl acetate breast 2.5%; Carboxymethyl cellulose acid sodium 0.3%, sodium alkyl benzene sulfonate 0.2%, sodium sulphate 0.2%, n-octyl alcohol 0.2%, AEO 0.15%, surplus is a water;
2) coating preparation:
A. mullite powder, silica flour and bauxite base-material are stirred in the coating grinding equipment, 40% the water that adds Total Water then is in base-material, and base-material is moistening and stir and open;
B. Ludox, polyvinyl acetate breast, the sour sodium of carboxymethyl cellulose, sodium alkyl benzene sulfonate, sodium sulphate, n-octyl alcohol, AEO are added successively above-mentioned moisteningly and stir in the base-material open, and 5% the water that adds Total Water stirs 60min in the coating grinding equipment;
C. then with 55% water of Total Water in the coating grinding equipment, and grind 180min and get final product.
Through test, the density of the lost foam paint that embodiment one to three prepares is 1.4-1.6g/cm
3, place suspensibility after 72 hours greater than 98%; The shear stress of coating is 16-19Pa.Use the apparent viscosity value that is coated with 4 viscometer determining coating to be 40-42s.The thixotroping rate is 15%-17%.The brushing index of coating, an amount of dropping down and a time of dropping down are about 6.0 respectively, 0.4g and 10s.The low temperature intensity of coating is higher than 800g/mm.Intensity through paint coatings after 1200 ℃ of roastings is higher than 600g/mm.The low temperature gas permeability of coating is higher than 13cm
2(kPamin)
-1, hot permeability is greater than 30cm
2(kPamin)
-1
Applicant's statement; The present invention explains detailed process equipment of the present invention and technological process through the foregoing description; But the present invention is not limited to above-mentioned detailed process equipment and technological process, does not mean that promptly the present invention must rely on above-mentioned detailed process equipment and technological process could be implemented.The person of ordinary skill in the field should understand, and to any improvement of the present invention, to the interpolation of the equivalence replacement of each raw material of product of the present invention and auxiliary element, the selection of concrete mode etc., all drops within protection scope of the present invention and the open scope.