Precoated sand and preparation method thereof

A technology of coated sand and phenolic resin, which is applied in the field of foundry industry, can solve the problems of poor heat resistance and collapsibility of coated sand, and achieve the effects of increasing rigidity, improving collapsibility, and increasing bulk density

Active Publication Date: 2017-10-24
山西科瑞再生资源综合利用有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention: Aiming at the defects of poor heat resistance and collapse of the currently prepared coated sand, a coated sand and its preparation method are provided

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0021] Weigh 100 g of solid thermoplastic phenolic resin and put it into a pulverizer to pulverize for 40 minutes to obtain phenolic resin powder. Add phenolic resin powder and 400 mL of acetone to a three-necked flask with a thermometer and a reflux device, stir and mix for 1 hour, and then add 30 mL2,4 -xylene diisocyanate, and the three-neck flask was moved into a digital display constant temperature speed measuring magnetic stirrer, and the temperature was 60 ° C, and the rotation speed was 250r / min. Wash the filter residue with water for 3 times, put it in an oven, and dry it at 95°C for 3 hours to obtain a modified phenolic resin. Finally, in parts by weight, take 100 parts of raw sand, 2 parts of modified phenolic resin, and 1 part of silane coupling agent KH-550, 0.3 part of urotropine and 1 part of ethyl acetate, heat the raw sand to 95°C and put it in the sand mixer, then add modified phenolic resin and silane coupling agent KH-550, stir and mix for 20 minutes After ...

example 2

[0023] Weigh 100g of solid thermoplastic phenolic resin and put it into a pulverizer to pulverize for 40 minutes to obtain phenolic resin powder. Add phenolic resin powder and 400mL of acetone to a three-necked flask with a thermometer and a reflux device, stir and mix for 1 hour, and then add 30mL2,4 -xylene diisocyanate, and the three-neck flask was moved into a digital display constant temperature speed measuring magnetic stirrer, and the temperature was 60 ° C, and the rotation speed was 250r / min. The filter residue was washed with water for 3 times, then placed in an oven, and dried at 95°C for 3 hours to obtain a modified phenolic resin. At the same time, 40 g of cerium dioxide, 100 mL of 25% hydrochloric acid and 5 mL of 30% hydrogen peroxide were added to the beaker , stirred and mixed for 30 minutes, then added 25 mL of hydroxyethylidene diphosphonic acid, stirred and reacted for 40 minutes, then added 15 mL of sodium persulfate with a mass fraction of 15%, and continu...

example 3

[0025]Weigh 100g of solid thermoplastic phenolic resin and put it into a pulverizer to pulverize for 40 minutes to obtain phenolic resin powder. Add phenolic resin powder and 400mL of acetone to a three-necked flask with a thermometer and a reflux device, stir and mix for 1 hour, and then add 30mL2,4 -xylene diisocyanate, and the three-neck flask was moved into a digital display constant temperature speed measuring magnetic stirrer, and the temperature was 60 ° C, and the rotation speed was 250r / min. The filter residue was washed with water for 3 times, then placed in an oven, and dried at 95°C for 3 hours to obtain a modified phenolic resin. At the same time, 40 g of cerium dioxide, 100 mL of 25% hydrochloric acid and 5 mL of 30% hydrogen peroxide were added to the beaker , stirred and mixed for 30 minutes, then added 25 mL of hydroxyethylidene diphosphonic acid, stirred and reacted for 40 minutes, then added 15 mL of sodium persulfate with a mass fraction of 15%, and continue...

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PUM

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Abstract

The invention discloses precoated sand and a preparation method thereof, and belongs to the technical field of the foundry industry. The precoated sand comprises, by weight, 100-110 parts of roughing sand, 2-4 parts of modified phenolic resin, 1-3 parts of a coupling agent, 0.3-0.5 part of urotropine, 0.6-0.8 part of modified lignin, 1-3 parts of a dry material, and 1-3 parts of ethyl acetate. The precoated sand is formed by combining the specific components, especially, 1-Hydroxyethylidene-1,1-diphosphonic acid can be catalyzed by ceric oxide to perform dehydration reaction with the modified phenolic resin during heating, resin carbonization is promoted, thus, the binding force between the resin and the sand is reduced, and the collapsibility of the precoated sand is improved; and in addition, the ceric oxide can also stop the modified phenolic resin from performing free radical reaction caused by oxidation, so that the heat resistance of the precoated sand is improved. Meanwhile, the invention further discloses the preparation method of the precoated sand. The method adopts the specific steps and the specific material adding sequence, and thus, the precoated sand which is good in heat resistance and prone to collapsing can be obtained quickly.

Description

technical field [0001] The invention relates to coated sand and a preparation method thereof, belonging to the technical field of foundry industry. Background technique [0002] Coated sand refers to the molding sand or core sand with a layer of solid resin film attached to the surface of the sand grains before molding. There are two coating processes: cold method and hot method: the cold method dissolves the resin with ethanol, and adds urotropine during the sand mixing process, so that the two are coated on the surface of the sand, and the ethanol volatilizes to obtain a sand film; The method is to preheat the sand to a certain temperature, add resin to melt it, stir to coat the resin on the surface of the sand, add urotropine aqueous solution and lubricant, cool, crush, and sieve to obtain coated sand. For steel castings and iron castings. Due to the advantages of high strength, low gas generation, high dimensional precision of production castings, smooth surface and ea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C1/22B22C1/02B22C5/04B22C5/06
CPCB22C1/02B22C1/2253B22C5/0409B22C5/06
Inventor 姜向军宋玲
Owner 山西科瑞再生资源综合利用有限公司
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