CN102688979A - Coated sand with long shelf life, and production method of coated sand - Google Patents
Coated sand with long shelf life, and production method of coated sand Download PDFInfo
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- CN102688979A CN102688979A CN2012102107856A CN201210210785A CN102688979A CN 102688979 A CN102688979 A CN 102688979A CN 2012102107856 A CN2012102107856 A CN 2012102107856A CN 201210210785 A CN201210210785 A CN 201210210785A CN 102688979 A CN102688979 A CN 102688979A
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Abstract
The invention provides coated sand with long shelf life and a production method of the coated sand. The coated sand is formed by silica sand, phenolic resin, a curing agent, a lubricant and boric acid, wherein 1-3 parts by weight of phenolic resin and 0.1-0.8 part by weight of boric acid are added in each 100 parts by weight of silica sand; the curing agent is urotropin, wherein 0.12-0.18 part by weight of urotropin is added in each one part by weight of phenolic resin; and the lubricant is calcium stearate, wherein 0.06-0.12 part by weight of calcium stearate is added in each one part by weight of phenolic resin. The production method comprises steps of heating silica sand to 100-130 DEG C; adding phenolic resin and boric acid into the obtained silica sand according to the proportion and mixing uniformly; adding urotropin into the obtained product according to the proportion and mixing uniformly; and adding calcium stearate into the obtained product according to the proportion and mixing uniformly.
Description
Technical field
The present invention relates to Modeling Material and production method thereof, especially relate to a kind of long shelf-life precoated sand and production method thereof.
Background technology
Precoated sand is sand grain surface promptly is covered with one deck hard resin film before moulding molding sand or a core sand.Two kinds of coating techniques of cold process and Re Fa are arranged: cold process with resin dissolves, and adds methenamine with ethanol in the mulling process, make the two be coated on sand grain surface, the ethanol volatilization, precoated sand; Hot method is preheating to uniform temperature to sand, adds resin and makes its fusion, stirs to make resin-coated at sand grain surface, adds the methenamine aqueous solution and lubricant, cooling, broken, sieve precoated sand.It is a kind of thermosetting resin sand the earliest, is invented in nineteen forty-four by German doctor Ke Ning.Its technical process is with the thermosetting phenolic resin of powdery and roughing sand mechanical mixture, solidifies during heating.Developed at present and added latent curing agent such as methenamine and lubricant such as calcium stearate with thermoplastic phenolic resins and be mixed with precoated sand through certain coating technique; When being heated, precoated sand is coated on the resin fusion of sand grain surface; Under the effect of the methylene that methenamine decomposites; The resin of fusion is transformed into the three-dimensional-structure of not fusion rapidly by linear structure, thereby precoated sand is solidified.Precoated sand is widely used in motor cylinder block, cylinder cap, inlet manifold, the production of various intricate castings such as all kinds of pipe fittings, the pump housing.
At present, the precoated sand of selling on the market, its fusing point are generally between 95 ℃～105 ℃, and such fusing point is in the winter time under the cryogenic conditions, generally can not lump in three months; And under the summer high temperature condition, one month even 10 days are less than just luming, and the shelf-life is short, and the serviceability of product is produced very big influence.Test shows, the fusing point that improves precoated sand helps prolonging its shelf-life, for example, when the fusing point of precoated sand reaches 110 ℃, in summer high temperature and moist environment, also can not lump in two months.How to improve the precoated sand fusing point, the shelf-life that prolongs precoated sand is the problem that the precoated sand technical field is eager to solve always.
At present; The way of the softening point through improving the used phenolic resins of precoated sand can improve the fusing point of precoated sand; After but the phenolic resins softening point improved, under the situation of same resin addition, its adhesion strength can reduce greatly; Cause precoated sand tension and bending strength not to reach technological requirement, need to increase amount of resin.Yet the increase amount of resin has not only increased the precoated sand production cost, and the phenolic resins in the precoated sand contains a small amount of harmful free phenol, and these phenol owing to be heated and can evaporate, produce flue gas in precoated sand production and use, endanger workers ' health.
In the past in precoated sand coremaking or modeling process, in order to accelerate the cross-linking reaction of phenolic resins and methenamine in the precoated sand, solidify as early as possible, enhance productivity, when producing precoated sand, often add some acidic materials as auxiliary agent.Mostly this type of material is organic acid, as: salicylic acid, benzoic acid, phthalic acid etc.Their affiliation that adds reduces the fusing point of precoated sand.
Summary of the invention
In order to overcome the defective of prior art; The technical problem that the present invention will solve is: a kind of long shelf-life precoated sand and production method thereof are provided; Through in producing the precoated sand process, adding a kind of material that can improve the overlay film melting point, produce a kind of precoated sand of growing the shelf-life.
In order to solve the problems of the technologies described above, on the one hand, the present invention provides a kind of long shelf-life precoated sand, and it is by comprising that silica sand, phenolic resins, curing agent, lubricant and boric acid processes; In wherein per 100 weight portion silica sands, add phenolic resins 1～3 weight portion, boric acid 0.1～0.8 weight portion; Said curing agent is a methenamine, and the phenolic resins of per 1 weight portion adds the methenamine of 0.12～0.18 weight portion; Said lubricant is a calcium stearate, and the phenolic resins of per 1 weight portion adds the calcium stearate of 0.06～0.12 weight portion.
On the other hand, the present invention also provides a kind of production method of growing the shelf-life precoated sand, and it may further comprise the steps:
S1: silica sand is heated to 100～130 ℃;
S2: in the silica sand that step S1 obtains, proportionally add phenolic resins and boric acid, mix;
S3: in the product that step S2 obtains, proportionally add methenamine, mix;
S4: in the product that step S3 obtains, proportionally add calcium stearate, mix.
Preferably, the production method of said long shelf-life precoated sand, the product that its step S4 obtains also passes through fragmentation.
The beneficial effect that the present invention brings: through adding the small amount of boron acid assistant, improve the fusing point of precoated sand, reduce the caking of precoated sand, thereby prolong its maintenance phase.
The specific embodiment
Illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.
Embodiment 1: the silica sand of 100 weight portions is heated to 100 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 1 weight portion and 0.1 weight portion, mix; In the product that obtains, mix add the aqueous solution of 0.18 weight portion methenamine by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.12 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand.
Embodiment 2: the silica sand of 100 weight portions is heated to 130 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 3 weight portions and 0.2 weight portion, mix; In the product that obtains, mix add the aqueous solution of 0.12 weight portion methenamine by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.06 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand.
Embodiment 3: the silica sand of 100 weight portions is heated to 115 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 2 weight portions and 0.3 weight portion, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.15 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.09 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand after the fragmentation.
Embodiment 4: the silica sand of 100 weight portions is heated to 105 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 1.5 weight portions and 0.4 weight portion, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.16 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.1 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand after the fragmentation.
Embodiment 5: the silica sand of 100 weight portions is heated to 110 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 2.5 weight portions and 0.5 weight portion, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.13 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.08 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand.
Embodiment 6: the silica sand of 100 weight portions is heated to 125 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 2.6 weight portions and 0.6 weight portion, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.17 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.11 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand.
Embodiment 7: the silica sand of 100 weight portions is heated to 120 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 2.3 weight portions and 0.8 weight portion, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.14 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.07 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand.
Embodiment 8: the silica sand of 100 weight portions is heated to 122 ℃; In the silica sand that obtains, behind the boric acid of the phenolic resins of adding 2.7 weight portions and 1.0 weight portions, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.14 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.08 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain long shelf-life precoated sand after the fragmentation.
Comparative Examples: the silica sand of 100 weight portions is heated to 115 ℃; After in the silica sand that obtains, adding the phenolic resins of 2 weight portions, mix; In the product that obtains, mix add the aqueous solution of methenamine of 0.15 weight portion by the phenolic resins of per 1 weight portion after; In the product that obtains, add the calcium stearate of 0.09 weight portion by the phenolic resins of per 1 weight portion after, mix, obtain precoated sand.
Embodiment 1～8 and Comparative Examples products obtained therefrom are by JB/T 8583-2007 " precoated sand is used in casting " appendix A: cast the test method that must survey fusing point in the performance indications with precoated sand, the fusing point of measurement products.Through test, the fusing point such as the following table of embodiment 1～8 and Comparative Examples products obtained therefrom.
| Embodiment | Fusing point (℃) |
| Embodiment 1 | 104 |
| Embodiment 2 | 108 |
| Embodiment 3 | 110 |
| Embodiment 4 | 112 |
| Embodiment 5 | 115 |
| Embodiment 6 | 118 |
| Embodiment 7 | 120 |
| Embodiment 8 | 120 |
| Comparative Examples | 100 |
Test result shows: add boric acid when producing length shelf-life precoated sand, the fusing point of precoated sand is improved than Comparative Examples, explains that the adding of boric acid helps improving the fusing point of precoated sand, prolongs the maintenance phase of product.Yet it is in per 100 weight portion silica sands, when the addition of boric acid surpasses 0.8 weight portion, not obvious to the fusing point that improves precoated sand.
For a person skilled in the art, the present invention also has various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (3)
1. one kind long shelf-life precoated sand is characterized in that: it is by comprising that silica sand, phenolic resins, curing agent, lubricant and boric acid processes; In wherein per 100 weight portion silica sands, add phenolic resins 1～3 weight portion, boric acid 0.1～0.8 weight portion; Said curing agent is a methenamine, and the phenolic resins of per 1 weight portion adds the methenamine of 0.12～0.18 weight portion; Said lubricant is a calcium stearate, and the phenolic resins of per 1 weight portion adds the calcium stearate of 0.06～0.12 weight portion.
2. the production method of the said long shelf-life precoated sand of claim 1, it is characterized in that: it may further comprise the steps:
S1: silica sand is heated to 100～130 ℃;
S2: in the silica sand that step S1 obtains, proportionally add phenolic resins and boric acid, mix;
S3: in the product that step S2 obtains, proportionally add methenamine, mix;
S4: in the product that step S3 obtains, proportionally add calcium stearate, mix.
3. according to the production method of the said long shelf-life precoated sand of claim 2, it is characterized in that: the product that said step S4 obtains also passes through fragmentation.
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| CN2012102107856A CN102688979A (en) | 2012-06-26 | 2012-06-26 | Coated sand with long shelf life, and production method of coated sand |
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| CN2012102107856A CN102688979A (en) | 2012-06-26 | 2012-06-26 | Coated sand with long shelf life, and production method of coated sand |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103658506A (en) * | 2013-12-31 | 2014-03-26 | 安顺学院 | Easy-to-fill precoated sand and preparation process thereof |
| CN104289661A (en) * | 2014-09-10 | 2015-01-21 | 湖北工业大学 | Preparation of coated sand by use of phosphate inorganic binder and molding method thereof |
| CN104325065A (en) * | 2014-10-08 | 2015-02-04 | 吴江市液铸液压件铸造有限公司 | Coated sand and preparation method thereof |
| CN104858357A (en) * | 2015-05-07 | 2015-08-26 | 马鞍山市恒毅机械制造有限公司 | Precoated sand with high-temperature resistance and good compactness and preparation method thereof |
| CN107695284A (en) * | 2017-10-10 | 2018-02-16 | 洪诗宏 | A kind of smoke-free and tasteless environment-friendly resin sand and its preparation technology |
| CN109047644A (en) * | 2018-09-28 | 2018-12-21 | 佛山齐安建筑科技有限公司 | A kind of preparation method of high-performance precoated sand |
| WO2019015044A1 (en) * | 2017-07-19 | 2019-01-24 | 南通国盛铸造有限公司 | High-performance low-cost crystrip for use with gray cast iron parts of machine tool |
| CN110102703A (en) * | 2019-05-07 | 2019-08-09 | 秦声旺 | A kind of novel environment friendly smoke-free and tasteless precoated sand and preparation method thereof |
| CN110102704A (en) * | 2019-05-28 | 2019-08-09 | 沙县宏盛塑料有限公司 | A kind of modification phenolic resin-based precoated sand and preparation method thereof |
| 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 |
| CN115971405A (en) * | 2022-12-05 | 2023-04-18 | 常熟东南塑料有限公司 | Modified phenolic resin precoated sand and preparation method thereof |
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| CN102448637A (en) * | 2009-07-23 | 2012-05-09 | 旭有机材工业株式会社 | Phenol resin composition for shell molding, resin-coated sand for shell molding, and mold for shell molding obtained using same |
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| US4113916A (en) * | 1974-09-27 | 1978-09-12 | Acme Resin Corporation | Shell sand with improved thermal shock resistance |
| JPH11309543A (en) * | 1998-04-22 | 1999-11-09 | Gun Ei Chem Ind Co Ltd | Resin-coated sand for shell mold |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103658506B (en) * | 2013-12-31 | 2016-03-30 | 安顺学院 | Easy filling precoated sand and preparation technology thereof |
| CN103658506A (en) * | 2013-12-31 | 2014-03-26 | 安顺学院 | Easy-to-fill precoated sand and preparation process thereof |
| CN104289661A (en) * | 2014-09-10 | 2015-01-21 | 湖北工业大学 | Preparation of coated sand by use of phosphate inorganic binder and molding method thereof |
| CN104325065A (en) * | 2014-10-08 | 2015-02-04 | 吴江市液铸液压件铸造有限公司 | Coated sand and preparation method thereof |
| CN104858357A (en) * | 2015-05-07 | 2015-08-26 | 马鞍山市恒毅机械制造有限公司 | Precoated sand with high-temperature resistance and good compactness and preparation method thereof |
| WO2019015044A1 (en) * | 2017-07-19 | 2019-01-24 | 南通国盛铸造有限公司 | High-performance low-cost crystrip for use with gray cast iron parts of machine tool |
| CN107695284A (en) * | 2017-10-10 | 2018-02-16 | 洪诗宏 | A kind of smoke-free and tasteless environment-friendly resin sand and its preparation technology |
| CN109047644A (en) * | 2018-09-28 | 2018-12-21 | 佛山齐安建筑科技有限公司 | A kind of preparation method of high-performance precoated sand |
| CN110102703A (en) * | 2019-05-07 | 2019-08-09 | 秦声旺 | A kind of novel environment friendly smoke-free and tasteless precoated sand and preparation method thereof |
| CN110102704A (en) * | 2019-05-28 | 2019-08-09 | 沙县宏盛塑料有限公司 | A kind of modification phenolic resin-based precoated sand and preparation method thereof |
| CN110102704B (en) * | 2019-05-28 | 2020-12-18 | 沙县宏盛塑料有限公司 | Modified phenolic resin-based precoated sand and preparation method thereof |
| 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 |
| CN115971405A (en) * | 2022-12-05 | 2023-04-18 | 常熟东南塑料有限公司 | Modified phenolic resin precoated sand and preparation method thereof |
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Application publication date: 20120926 |