CN110722094A - Resin self-hardening sand resin mixture for casting and preparation method thereof - Google Patents
Resin self-hardening sand resin mixture for casting and preparation method thereof Download PDFInfo
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- CN110722094A CN110722094A CN201911245563.6A CN201911245563A CN110722094A CN 110722094 A CN110722094 A CN 110722094A CN 201911245563 A CN201911245563 A CN 201911245563A CN 110722094 A CN110722094 A CN 110722094A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
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Abstract
The invention discloses a resin self-hardening sand resin mixture for casting and a preparation method thereof, wherein the resin mixture is prepared from the following raw materials: benzoxazine resin, fluorinated phosphazene rubber, phthalonitrile, chromium quartz powder, cordierite powder, serpentine powder, cyanite powder, a curing agent, a regulator, polycarbosilane, konjac glucomannan, polyvinylpyrrolidone and a vulcanizing agent. The preparation method is simple, and the components have synergistic effect, so that the cohesiveness of sand grains and resin can be enhanced, the strength of core sand can be improved, the cross-linking strength of the core sand can be improved, and certain moisture absorption is realized, so that the casting efficiency is improved, and the casting cost is reduced.
Description
Technical Field
The invention belongs to the technical field of casting, and particularly relates to a resin self-hardening sand resin mixture for casting and a preparation method thereof.
Background
The resin sand has poor air permeability, so that gas generated in the casting mold is difficult to discharge when metal liquid is poured, the casting is prevented from generating air hole defects, the casting mold is easy to be not hard to penetrate, and the casting mold is easy to damage when the casting mold is taken out. The hardening process of acid-hardened furan resin and phenolic resin is condensation reaction, and the hardening reaction can not be continued as long as moisture is released during the crosslinking reaction of the resin and cannot be discharged. After the self-hardening sand is molded, the outer surface of the casting mold, which is in contact with the atmosphere, is easy to harden, the inside of the casting mold is not easy to harden, the moisture on the outer surface is easy to evaporate, the moisture on the inside is not easy to discharge, and the casting mold is difficult to harden.
The fluidity of the resin self-hardening sand of the casting mold is much better than that of the clay sand, the energy required for pounding the casting mold is far lower than that of the clay sand, the casting mold is easy to fill, and the hard false impression can be given to people after demolding even if pounding is not performed due to the high bonding strength of the resin. Many people are masked by the false impression when adopting the resin self-hardening sand process and cannot process the false impression in time, which becomes a common problem in the casting industry of China and is one of the important reasons causing the low quality of castings. After the molten metal is poured into the casting mold, the resin is decomposed and gasified by heating, loose sand grains lose support, the casting mold is easy to generate phenomena of yielding, cracking, peeling and the like under the pressure action of the molten metal, and the casting has the defects of sand expansion, sand sticking, vein-shaped crack, large-area sand inclusion and the like. The nodular cast is easy to produce a casting mold with large shrinkage porosity and shrinkage cavity inside, after demolding, a long crack is generated in the continuous hardening process, the surface of the casting mold forming core is embrittled due to surface embrittlement of the conventional resin self-hardening sand, and the defects of sand washing, sand sticking, vein lines and the like are easy to generate on the casting. If the sand temperature is too low, the hardening is too slow, the demoulding time is obviously prolonged, the production rhythm is influenced, the existing furan resin sand has the defects that the high-temperature strength is high, the deformability is poor, macroscopic thermal cracks are easily generated on the surface of a casting, harmful element sulfur permeates to the surface of the casting at high temperature, the sulfur is increased on the surface of the casting, the capillary cracks are easily generated on the casting, the defects that the service time, the demoulding time and the final strength are greatly influenced by the change of the environmental temperature and humidity, the normal-temperature strength of alkaline phenolic resin sand is lower, the resin addition amount in the molding (core) sand is larger, and the surface stability is poorer
Although the curing speed (mold drawing time) is slightly faster than that of furan-feeding resin sand and sodium silicate sand, the productivity is still lower than that of phenol-urethane resin sand, the potential is not fully exerted, the problem that the heat conductivity of the alkaline phenolic resin sand is inferior to that of any other resin sand for recycling is not completely solved, the curing process is greatly influenced by the moisture in the molding sand and the environmental humidity, during casting, the aromatic solvent migrates from the surface layer to the inner layer to form a low-strength condensation zone, so that the molding (core) sand is softened and has low heat strength, thereby causing the defects of sand washing, fin flying, deformation and the like of the casting, the used solvent and amine curing agent are toxic, obvious odor exists in sand mixing, core making, modeling and pouring places, smoke exists during pouring, the mass fraction of nitrogen is high (4% -5%), steel castings are prone to generate air holes, the surfaces of the castings have bright carbon defects, and the like.
The development of new high performance foundry resin self-hardening sand resin mixtures to meet higher use requirements is highly desirable.
Disclosure of Invention
The invention aims to solve the existing problems and provides a resin mixture of self-hardening sand for casting and a preparation method thereof.
The invention is realized by the following technical scheme:
a resin self-hardening sand resin mixture for casting is prepared from 33 ~ 45 parts of poly (arylene ether nitrile), 61 ~ 77 parts of benzoxazine resin, 11 ~ 017 parts of fluorinated phosphazene rubber, 7 ~ 113 parts of phthalonitrile, 3 ~ 27 parts of allite powder, 2 ~ 35 parts of cordierite powder, 3 ~ 6 parts of serpentine powder, 4 ~ 7 parts of sapphire powder, 0.5 ~ 1 part of curing agent, 1 ~ 2 parts of regulator, 5 ~ 8 parts of polycarbosilane, 3 ~ 6 parts of konjac glucomannan, 1 ~ 2 parts of polyvinylpyrrolidone and 1 ~ 2 parts of vulcanizing agent by weight.
Further, the benzoxazine resin is cyclotriphosphazene type benzoxazine, and specifically, 100 parts by weight of a formaldehyde aqueous solution with the mass percentage concentration of 40% and 200-280 parts by weight of mixed dichlorobenzene are added into a reaction kettle, the mixture is stirred and cooled by ice water, the pH value is adjusted to 7-7.8 by edible alkali, 65-73 parts by weight of n-butylamine is added dropwise, the reaction temperature is controlled to be not more than 5 ℃, the reaction is carried out for 10-25 min at 0-4 ℃ after the dropwise addition is finished, then 250 ~ 300 parts by weight of cyclotriphosphazene phenol and 400-500 parts by weight of mixed dichlorobenzene are added into the reaction kettle, the reaction system is heated to 145-160 ℃ for reflux, the reaction is carried out for 50-60 hours, the cyclotriphosphazene type benzoxazine resin liquid is prepared and then stands for layering, the water phase is removed, the solvent is removed by reduced pressure distillation, and the reduced pressure distillation is stopped when the solvent and the water are absent, so that the cyclotriphosphazene type benzoxazine resin is.
Further, the curing agent is prepared by phthalic anhydride and triethylene tetramine or diethylenetriamine according to the weight ratio of 1: 1 respectively; the regulator is one or a mixture of more than two of 2-methylimidazole, methyl ricinoleate and butanediol dimethacrylate.
Further, the vulcanizing agent is a mixture of bis- (gamma-triethoxysilylpropyl) tetrasulfide, lanthanum diethyldithiocarbamate and lanthanum N-N-hexylmaleamic acid.
Further, the fluorinated phosphazene rubber is one of PNF200 or FPNM 3700.
Further, the polyarylene ether nitrile was a powder having a melt index of 360 ℃ and 5kg (ASTM D1238) of 10 ~ 20g/10 min.
A preparation method of a resin self-hardening sand resin mixture for casting is characterized by comprising the following steps:
(1) adding curing agent, vulcanizing agent and regulator into the chrome quartz powder, cordierite powder, serpentine powder and kyanite powder, stirring uniformly at low temperature to obtain material A, (2) fully mixing benzoxazine resin, fluorinated phosphazene rubber and phthalonitrile, standing for 30min, drying at 160 ~ 180 ℃ for 3 ~ 4h, cooling, adding polycarbosilane, konjac glucomannan and polyvinylpyrrolidone, and stirring the mixture for 10 ~ 15min under microwave frequency of 2450MHz to obtain material B, (3) adding material A into material B, adding the mixture, and fully mixing uniformly to obtain a resin mixture.
The invention has the beneficial effects that:
the nitrile group of the fluorinated phosphazene rubber and the nitrile group of the polyaryl ether nitrile can generate trimerization reaction with the nitrile group as the plasticizer, namely phthalonitrile, so that triazine ring is generated by crosslinking, the nitrile group has polarity, the nitrile group of the phthalonitrile is easy to form hydrogen bond with hydroxyl on the surface of the packing of the chromylite powder, the cordierite powder, the serpentine stone powder and the kyanite powder under a specific vulcanization heat treatment state, so that the interface cohesive force is improved, the rheological property of the material is improved, the strength of the material is further improved, the crosslinking reaction is shown to be generated between the polymer and the packing at high temperature, the motion of a high molecular chain segment is limited by the crosslinking reaction, the effect similar to a coupling agent is realized, the further compatibility of the components of the fluorinated phosphazene rubber, the polyaryl ether nitrile and the benzoxazine resin is promoted, the effect of the packing coupling agent is realized, and the compatibilization effect is also realized. The addition of the polycarbosilane and other fillers not only improves the thermal conductivity of the resin mixture and leads heat out in time so as to reduce the temperature of a contact part, but also not only can play a role in vulcanization crosslinking in a system by a vulcanizing agent consisting of bis- (gamma-triethoxysilylpropyl) tetrasulfide, lanthanum diethyldithiocarbamate and lanthanum N-N-hexyl maleamate, but also can indirectly play a role in a coupling agent and a softening agent by being coupled with the fillers, can obviously reduce the viscosity of the fillers and the resin and endow the resin mixture with good processing performance. And secondly, the benzoxazine has the characteristic of ring-opening polymerization, no micromolecules are released during curing, a network structure similar to cross-linking is formed after curing, the curing shrinkage is small, the porosity is low, the benzoxazine has excellent mechanical properties and high heat resistance and flame retardance, and the introduction of the fluorinated phosphazene rubber and the polyaryl ether nitrile not only reduces the curing temperature, but also reduces the curing time and improves the cross-linking density and toughness of a cured product.
Compared with the prior art, the invention has the following advantages:
the preparation method is simple, the components are mutually synergistic, and the vulcanizing agent not only can improve the crosslinking density, but also can play a role of a coupling agent. The self-hardening sand prepared by the method has the advantages of small gas evolution, good hardening effect, high strength, high compressive strength after hardening, greatly reduced hot cracking phenomenon compared with the prior art, smooth surface, good sand sticking resistance and deformation resistance, uniform integral hardening of the sand mold, high casting size accuracy and suitability for production of large steel casting sand molds.
Detailed Description
The invention is illustrated by the following specific examples, which are not intended to be limiting.
Example 1
A resin self-hardening sand resin mixture for casting is prepared from 33 parts by weight of poly (arylene ether nitrile) 33 ~ 45 parts by weight, 77 parts by weight of benzoxazine resin, 17 parts by weight of phosphonitrile fluoride rubber, 13 parts by weight of phthalonitrile, 7 parts by weight of cristobalite powder, 5 parts by weight of cordierite powder, 6 parts by weight of serpentine powder, 7 parts by weight of cyanite powder, 1 part by weight of curing agent, 2 parts by weight of regulator, 8 parts by weight of polycarbosilane, 6 parts by weight of konjac glucomannan, 2 parts by weight of polyvinylpyrrolidone and 2 parts by weight of vulcanizing agent.
Further, the benzoxazine resin is cyclotriphosphazene benzoxazine, specifically, 100 parts by weight of a formaldehyde aqueous solution with the mass percentage concentration of 40% and 200 parts by weight of mixed dichlorobenzene are added into a reaction kettle, the mixture is stirred and cooled by ice water, the pH value is adjusted to 7.8 by edible alkali, 65 parts by weight of n-butylamine is added dropwise, the reaction temperature is controlled to be not more than 5 ℃, after the dropwise addition, the reaction is carried out for 25 minutes at 0-4 ℃, then 250 parts by weight of cyclotriphosphazene phenol and 400 parts by weight of mixed dichlorobenzene are added into the reaction kettle, the reaction system is heated to 160 ℃ for reflux, the reaction is carried out for 50 hours, after cyclotriphosphazene benzoxazine resin liquid is prepared, standing and layering are carried out, a water phase is removed, reduced pressure distillation is carried out again, the solvent is removed, and when no solvent or water is removed, the reduced pressure distillation is stopped, and the cyclotriphosphazene benzoxazine resin is prepared.
Further, the curing agent is prepared by phthalic anhydride and triethylene tetramine or diethylenetriamine according to the weight ratio of 1: 1 respectively; the regulator is one or a mixture of more than two of 2-methylimidazole, methyl ricinoleate and butanediol dimethacrylate.
Further, the vulcanizing agent is a mixture of bis- (gamma-triethoxysilylpropyl) tetrasulfide, lanthanum diethyldithiocarbamate and lanthanum N-N-hexylmaleamic acid.
Further, the fluorinated phosphazene rubber is one of PNF200 or FPNM 3700.
Further, the polyarylene ether nitrile was a powder having a melt index of 360 ℃ and 5kg (ASTM D1238) of 10 ~ 20g/10 min.
A preparation method of a resin self-hardening sand resin mixture for casting comprises the following steps:
(1) adding a curing agent, a vulcanizing agent and a regulator into the chromite powder, the cordierite powder, the serpentine powder and the kyanite powder, and uniformly stirring at low temperature to obtain a material A; (2) fully mixing benzoxazine resin, phosphonitrile fluoride rubber and phthalonitrile, standing for 30min, drying at 180 ℃ for 4h, cooling, adding polycarbosilane, konjac glucomannan and polyvinylpyrrolidone, and performing microwave treatment on the mixture at microwave frequency of 2450MHz and stirring for 15min to obtain a material B; and (3) adding the material A into the material B, adding, and fully and uniformly mixing to obtain a resin mixture.
Example 2
A resin self-hardening sand resin mixture for casting is prepared from 33 ~ 45 parts of poly (arylene ether nitrile), 61 parts of benzoxazine resin, 11 parts of phosphonitrile fluoride rubber, 7 parts of phthalonitrile, 3 parts of chrome quartz powder, 2 parts of cordierite powder, 3 parts of serpentine stone powder, 4 parts of kyanite powder, 0.5 part of curing agent, 1 part of regulator, 5 parts of polycarbosilane, 3 parts of konjac glucomannan, 1 part of polyvinylpyrrolidone and 1 part of vulcanizing agent by weight.
Further, the benzoxazine resin is cyclotriphosphazene type benzoxazine, specifically, 100 parts by weight of formaldehyde aqueous solution with the mass percentage concentration of 40% and 280 parts by weight of mixed dichlorobenzene are added into a reaction kettle, the mixture is stirred and cooled by ice water, the pH value is adjusted to 7.8 by edible alkali, 73 parts by weight of n-butylamine is added dropwise, the reaction temperature is controlled to be not more than 5 ℃, after the dropwise addition is finished, the reaction is carried out for 25 minutes at the temperature of 0-4 ℃, then 300 parts by weight of cyclotriphosphazene phenol and 400 parts by weight of mixed dichlorobenzene are added into the reaction kettle, the reaction system is heated to 160 ℃ for reflux, the reaction is carried out for 60 hours, after cyclotriphosphazene type benzoxazine resin liquid is prepared, standing and layering are carried out, a water phase is removed, reduced pressure distillation is carried out again, the solvent is removed, and when no solvent or water is removed, the reduced pressure distillation is stopped, and the cyclotriphos.
Further, the curing agent is prepared by phthalic anhydride and triethylene tetramine or diethylenetriamine according to the weight ratio of 1: 1 respectively; the regulator is one or a mixture of more than two of 2-methylimidazole, methyl ricinoleate and butanediol dimethacrylate.
Further, the vulcanizing agent is a mixture of bis- (gamma-triethoxysilylpropyl) tetrasulfide, lanthanum diethyldithiocarbamate and lanthanum N-N-hexylmaleamic acid.
Further, the fluorinated phosphazene rubber is one of PNF200 or FPNM 3700.
Further, the polyarylene ether nitrile was a powder having a melt index of 360 ℃ and 5kg (ASTM D1238) of 10 ~ 20g/10 min.
A preparation method of a resin self-hardening sand resin mixture for casting comprises the following steps:
(1) adding a curing agent, a vulcanizing agent and a regulator into the chromite powder, the cordierite powder, the serpentine powder and the kyanite powder, and uniformly stirring at low temperature to obtain a material A; (2) fully mixing benzoxazine resin, phosphonitrile fluoride rubber and phthalonitrile, standing for 30min, drying at 160 ℃ for 4h, cooling, adding polycarbosilane, konjac glucomannan and polyvinylpyrrolidone, and performing microwave treatment on the mixture at microwave frequency of 2450MHz and stirring for 15min to obtain a material B; and (3) adding the material A into the material B, adding, and fully and uniformly mixing to obtain a resin mixture.
TABLE 1 results of performance test of resin mixture of self-hardening sand for foundry for each example and comparative example
Note: the comparative example and the example are both resin self-hardening sand, and the components of the sand comprise, by mass, 100% of standard sand silica sand, 7% of resin mixing and adding amount which is 1.8% of the total weight of the silica sand, weighing the sand according to the proportion, pouring the weighed sand into a sand mixer, mixing for 4 minutes, mixing for 6 minutes, adding the resin mixture, mixing for 4 minutes, finally adding a curing agent, mixing for 4 minutes, discharging the sand for preparing a sand core, and GB/T25138-2010 testing the standard sand for a casting binder.
Claims (7)
1. A resin self-hardening sand resin mixture for casting is prepared from 33 ~ 45 parts of poly (arylene ether nitrile), 61 ~ 77 parts of benzoxazine resin, 11 ~ 017 parts of fluorinated phosphazene rubber, 7 ~ 113 parts of phthalonitrile, 3 ~ 27 parts of allite powder, 2 ~ 35 parts of cordierite powder, 3 ~ 6 parts of serpentine powder, 4 ~ 7 parts of sapphire powder, 0.5 ~ 1 part of curing agent, 1 ~ 2 parts of regulator, 5 ~ 8 parts of polycarbosilane, 3 ~ 6 parts of konjac glucomannan, 1 ~ 2 parts of polyvinylpyrrolidone and 1 ~ 2 parts of vulcanizing agent by weight.
2. The resin self-hardening sand resin mixture for casting as claimed in claim 1, wherein the benzoxazine resin is cyclotriphosphazene type benzoxazine, and specifically, 100 parts by weight of a formaldehyde aqueous solution with a mass percentage concentration of 40% and 200 to 280 parts by weight of mixed dichlorobenzene are added into a reaction kettle, the mixture is stirred, ice water is cooled, the pH value is adjusted to 7 to 7.8 by using edible alkali, 65 to 73 parts by weight of n-butylamine is added dropwise, the reaction temperature is controlled to be not more than 5 ℃, the reaction is carried out at 0 to 4 ℃ for 10 to 25min, then 250 ~ 300 parts by weight of cyclotriphosphazene phenol and 400 to 500 parts by weight of mixed dichlorobenzene are added into the reaction kettle, the reaction system is heated to 145 to 160 ℃ for reflux, the reaction is carried out for 50 to 60 hours, after the cyclotriphosphazene type benzoxazine resin liquid is prepared, the reaction solution is left for layering, the aqueous phase is removed, reduced pressure distillation is carried out again, the solvent is removed, and when no solvent or water is removed, the reduced pressure distillation is stopped, and the cyclotriphosphazene type benzoxazine resin is.
3. The resin mixture of self-hardening sand for casting as claimed in claim 1, wherein the curing agent is prepared from phthalic anhydride and triethylene tetramine or diethylene triamine in a weight ratio of 1: 1; the regulator is one or a mixture of more than two of 2-methylimidazole, methyl ricinoleate and butanediol dimethacrylate.
4. The resin composition as claimed in claim 1, wherein the vulcanizing agent is a mixture of bis- (γ -triethoxysilylpropyl) tetrasulfide, lanthanum diethyldithiocarbamate and lanthanum N-hexylmaleamic acid.
5. The foundry resin self-hardening sand resin mixture of claim 1, wherein the fluorinated phosphazene rubber is one of PNF200 or FPNM 3700.
6. The self-hardening sand resin mixture for foundry use according to claim 1, wherein the polyarylene ether nitrile is a powder having a melt index of 360 ℃ and 5kg (ASTM D1238) of 10 ~ 20g/10 min.
7. The preparation method of the resin self-hardening sand resin mixture for casting according to claim 1, comprising the steps of (1) adding a curing agent, a vulcanizing agent and a regulator into the chromium quartz powder, the cordierite powder, the serpentine powder and the kyanite powder, and uniformly stirring at a low temperature to obtain a material A, (2) fully mixing the benzoxazine resin, the fluorinated phosphazene rubber and the phthalonitrile, standing for 30min, drying at 160 ~ 180 ℃ for 3 ~ 4h, cooling, adding polycarbosilane, konjac glucomannan and polyvinylpyrrolidone, performing microwave treatment on the mixture at a microwave frequency of 2450MHz for 10 ~ 15min, and (3) adding the material A into the material B, adding the mixture, and uniformly mixing to obtain the resin mixture.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911245563.6A CN110722094A (en) | 2019-12-07 | 2019-12-07 | Resin self-hardening sand resin mixture for casting and preparation method thereof |
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| CN201911245563.6A CN110722094A (en) | 2019-12-07 | 2019-12-07 | Resin self-hardening sand resin mixture for casting and preparation method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111957879A (en) * | 2020-09-01 | 2020-11-20 | 和县华顺铸造有限公司 | Preparation method of high-strength centrifugal casting coated molding sand |
| CN112692226A (en) * | 2020-12-09 | 2021-04-23 | 南昌科勒有限公司 | Hot core box resin sand and resin sand core comprising same |
| CN112692742A (en) * | 2020-12-23 | 2021-04-23 | 苏州远东砂轮有限公司 | Manufacturing method of flexible paper-based abrasive paper and abrasive paper |
-
2019
- 2019-12-07 CN CN201911245563.6A patent/CN110722094A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111957879A (en) * | 2020-09-01 | 2020-11-20 | 和县华顺铸造有限公司 | Preparation method of high-strength centrifugal casting coated molding sand |
| CN112692226A (en) * | 2020-12-09 | 2021-04-23 | 南昌科勒有限公司 | Hot core box resin sand and resin sand core comprising same |
| CN112692742A (en) * | 2020-12-23 | 2021-04-23 | 苏州远东砂轮有限公司 | Manufacturing method of flexible paper-based abrasive paper and abrasive paper |
| CN112692742B (en) * | 2020-12-23 | 2021-12-14 | 苏州远东砂轮有限公司 | Manufacturing method of flexible paper-based abrasive paper and abrasive paper |
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Application publication date: 20200124 |