CN1298774A - Composite disperser of sand in coating phenolic resin and its preparing process - Google Patents
Composite disperser of sand in coating phenolic resin and its preparing process Download PDFInfo
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- CN1298774A CN1298774A CN 99120102 CN99120102A CN1298774A CN 1298774 A CN1298774 A CN 1298774A CN 99120102 CN99120102 CN 99120102 CN 99120102 A CN99120102 A CN 99120102A CN 1298774 A CN1298774 A CN 1298774A
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Abstract
The invented disintegrating agent composition for phenolformaldehyde cover-membrane sand is composed of nitrate, chloride, cresol, fluorescein sodium salt. Said disintegrating agent can be directly used in the production of disintegrable thermoplastic phenol formaldehyde resin and disintegrable cover-membrane sand, during casting of light metal alloy such as aluminium alloy, the thermodecomposing substance of disintegrating agent and molecular chain of phenol formaldehyde resin react mutually so as to disintegrate phenolformaldehyde resin, thereby to promote the disintegration of phenol formaldehyde resin cover membrane sand mould or sand core.
Description
The invention relates to a composition of a dispersing agent consisting of nitrate, chloride, cresol, sodium fluorescein salt and ethanol and a preparation method thereof, in particular to a dispersing agent of thermoplastic phenolic resin coated sand for aluminum alloy casting production.
Since the european automobile industry developed the aluminum casting industry first in the twentieth century, aluminum alloy castings played a great role in reducing the self weight of automobiles, and received attention from various automobile factories. For this reason, the casting technology of aluminum alloys has also been rapidly developed to allow the development of processes such as metal/sand gravity casting, squeeze casting, low pressure casting, liquid die forging, semi-solid die casting, and spray molding. For casting production of aluminum alloy parts with complex shapes and structures, suchas cylinder bodies, cylinder covers, air inlet pipes and the like of automobile engines, the cavity structures of the aluminum alloy parts must be formed by sand cores. Currently, in the casting production of aluminum alloy, the adopted core making process and materials are mostly as follows: the method mainly comprises a hot box method of Funane resin sand, a phenolic polyurethane (urethane) resin cold box and self-hardening method, oil sand, clay and the like, and most of the core making processes which are widely adopted abroad are phenolic polyurethane resin cold boxes such as some automobile factories of France, America and Germany. The binder for the material has relatively low thermal decomposition temperature, so the sand core has good collapsibility in the casting process, but under certain production conditions and production environment,the above-described core materials and methods often exhibit some inadequacy. Therefore, in many factories, the characteristic and the characteristic of the phenolic resin precoated sand are combined, and a phenolic resin precoated sand shell method/thermal method core making process is selected in the aluminum alloy casting production. Since the binder used in the phenolic resin coated sand is usually a thermoplastic phenolic resin, and the relative thermal decomposition temperature of the resin is high (the binding energy between carbons in the phenolic resin is high, such as the alkane C-C binding energy is 345.6KJ/mol, the aromatic ring C-C binding energy is 523.4KJ/mol, and the C = C binding energy is 607.1K (J/mol), for the casting production of aluminum alloy (the casting temperature is usually 650-750 ℃), the sand cleaning difficulty of the casting is often caused due to the low thermal decomposition rate of the resin and the poor collapsibility of the sand core, and the casting waste is caused, some foundries and coated sand manufacturers are in order to ensure the production of complex aluminum alloy castings, and the resin addition amount of the coated sand is reduced, the strength of the sand core is sacrificed for replacing the collapsibility improvement of the sand core, so that the sand core is broken in the core making and casting processes due to the low strength of the sand core in the production, core waste and casting waste are caused, and the casting production is influenced. Even in this case, the collapsing effect of the precoated sand is not ideal in actual production, and the sand core is difficult to fall out, which often affects production. Still other manufacturers add halides and carbon to the precoated sandAcid salt, light oxide, phosphate, KMnO4FeO powder, peroxide, etc., and the addition of these additives lowers the strength of the precoated sand to some extent. Such as: heating 100kg of inner covering scouring sand (15Q) to 135 ℃, then unloading the inner covering scouring sand into a balance wheel type precoated sand mixer, adding common flaky thermoplastic phenolic resin PF901.5 kg for precoating for 30s, adding plasticizer DBP0.15kg, then mixing the sand for 20s, adding 750ml of 30% hexamethylene tetramine solution, then adding 0.07kg of calcium stearate, continuously mixing the sand for 30s, blowing and cooling, discharging the material after the precoated sand is completely dispersed, and thus preparing the precoated sand. The performance of the precoated sand is as follows: thermal tensile strength of 1.42MPa, normal temperature tensile strength of 2.39MPa, melting point of 104 ℃, gas forming amount of 13.4ml/g, collapsibility) of 0.5 MPa.
The invention aims to solve the problems and provides a dispersing agent composition of thermoplastic phenolic resin coated sand for casting production of light metals such as aluminum alloy and the like and a preparation method thereof.
The binder used for the phenolic resin coated sand is thermoplastic phenolic resin, and in the castingproduction process, after the sand core is coated by molten metal, C, H, O in the binder interacts under the action of heat to form CO and CO2、H2O, CmHn, etc. decompose the molecular structure of the resin, and collapse of the sand core occurs. Generally, the higher the temperature of the molten metal, the more easily the C-C bond is broken, the higher the mutual bonding rate of C, H, O, the higher the collapse rate of the core, and vice versa. In the phenolic resin coated sand, the content of C in the phenolic resin is more than 80%, the content of H is about 8%, and the content of O is about 12%, so that a reducing atmosphere is formed after the sand core is coated by molten metal in the casting process. For casting iron alloy, because the casting pouring temperature of the iron alloy is high (above 1380 ℃), the linkage between C and C is easy to break, and the mutual combination between C, H, O forms CO and CO2、H2The probability of O, CmHn and the like is high, and the molecular structure of the resin can be dispersed; however, in the case of aluminum alloy, since the melting point of the aluminum alloy is relatively low, the casting temperature is generally 650 to 750 ℃, and under such conditions, the C-C bond in the resin is relatively broken to a small extent, and a carbon residue bone chain is formed
It was confirmed by scholars both in Japan and USA that the sand core is difficult to collapse because of its presence in the core. The higher the addition of the phenolic resin, the more the residual carbon bone chains are, and the collapsibility of the precoated sand isThe worse the sex. Therefore, in the casting production of aluminum alloy, if the residual carbon bone chain of the phenolic resin can be broken or the amount of the residual carbon bone chain of the resin can be reduced, the collapse problem of the sand core can be solved.
There are various methods for breaking the residual carbon skeleton chain of the phenolic resin or reducing the amount of the residual carbon skeleton chain of the resin, and physical methods and chemical methods are broadly described. The physical method is to break the carbon residue bone chain of the resin by applying external stress, thereby realizing the disintegration of the sand core, such as adopting a casting core removing machine or manual shocking, and the like. The chemical method is to add a composition of a certain kind of chemical materials into resin or precoated sand, and decompose or break or deform the carbon residue bone chain of the resin through the decomposition of the chemical materials, so as to break the carbon residue bone chain of the resin and realize the disintegration of the sand core. The two methods have the advantages and the disadvantages, the physical method is simple to operate, the performance requirement on the core making material is not high, the adaptability is wide, but the removal of the sand core is limited by the factors of the complexity, the quality and the like of the casting, the core removal period is long, and the equipment investment is large. The chemical method has high performance requirements on core making materials, the removal of the sand core is not limited by the shape and the size of a casting, and the core removal period is relatively short. Through the principle comparison and analysis, the collapsing agent for the phenolic resin coated sand is developed, and the collapsing of the sand core is realized by a chemical method. The material used in the composition of the disintegrator should be considered to have a suitable decomposition temperature in the range of 400 ℃ to 600 ℃, and if the decomposition temperature is low ((350 ℃), the disintegrator-coated sand will decompose during molding or core making, affecting the strength of the sand mold or sand core, and if the decomposition temperature is too high (>650 ℃), the decomposition ofthe phenolic resin will not be promoted.
The invention provides a disintegrator composition, which consists of nitrate capable of decomposing at 400-600 ℃ and releasing oxygen, chloride capable of adjusting the decomposition temperature of the nitrate, protective agents cresol and fluorescein sodium salt which play a role in protecting thermal decomposition products of the nitrate, water and ethanol which are prepared as vectors; the nitrate as the main body of the disperser can be sodium nitrate, potassium nitrate, strontium nitrate, sodium nitrite, preferably sodium nitrate, and the nitrate is used for releasing oxygen at 400-600 ℃, and the thermal reaction equation of the nitrate is as follows: (ii) a The chloride can be sodium chloride and potassium chloride, preferably sodium chloride, and can be used as an accelerator for thermal decomposition of nitrate, so that the thermal decomposition speed of nitrate at a certain temperature can be accelerated, and the thermal decomposition temperature of nitrate can be adjusted; cresol, 2.6 di-tert-butyl-p-cresol, and sodium fluorescein salt act as a protective agent for thermal decomposition products of nitrates.
The nitrate accounts for 20-70% of the total weight of the dispersing agent, and preferably 30-50%; the chloride accounts for 0-5% of the total weight of the dispersing agent, and can also be 0%; 2.6 di-tert-butyl-p-cresol accounting for 0-25 percent of the total weight of the dispersing agent, preferably 0-10 percent, and also can be 0 percent; the fluorescein sodium salt accounts for 0-1% of the total weight of the collapsint, can also be 0%, and preferably 0-0.05%; the water accounts for 20-70% of the total weight of the dispersing agent; the ethanol accounts for 0-10% of the total weight of the dispersing agent.
The preparation method of the disintegrator compositionprovided by the invention comprises the following steps: dissolving 2, 6-di-tert-p-cresol in ethanol for later use; adding water and nitrate into a container with a stirring device, starting the stirrer, dripping the alcohol solution of 2.6 di-tert-p-cresol after the nitrate is dissolved, then adding chloride, adding sodium fluorescein salt after the chloride is completely dissolved, and continuously stirring to prepare the collapsing agent.
The collapsint composition provided by the invention can be directly used in the synthesis process of the thermoplastic phenolic resin to form the easily collapsible thermoplastic phenolic resin; the method can also be directly used in the production process of the precoated sand to form the easily collapsible precoated sand.
The invention has the following outstanding effects: the dispersing agent is suddenly decomposed when heated to about 500 ℃, the decomposed product of the dispersing agent interacts with the phenolic resin at high temperature, and molecular chains of the phenolic resin are deformed, broken and decomposed through physical chemistry and high polymer degradation reaction to reduce the bonding strength of the phenolic resin, so that the sand core is dispersed; at temperatures below 400 ℃, the disintegrator is stable in nature and does not react with the components of the coated sand system. Therefore, the dispersing agent has no influence on the physical and chemical properties of the precoated sand, such as strength, melting point, thermal expansion coefficient, thermal deformation and the like, on the premise of greatly improving the collapsibility of the precoated sand.
The examples described below illustrate the invention in detail. In these examples, all parts and percentages are by weight unless otherwise indicated.
Example 1: this example describes the formulation of adisintegrant composition.
Dissolving 10 parts of 2, 6-di-tert-butyl-p-cresol in 20 parts of ethanol for later use; 6000 parts of water and 4000 parts of nitrate are added into a container with a stirring device, the stirrer is started, 2.6 di-tert-p-cresol alcoholic solution is dripped after the nitrate is dissolved, 5 parts of chloride is added, 0.05 part of fluorescein sodium salt is added after the chloride is completely dissolved, and the mixture is stirred for 5-10 min to be discharged.
Example 2: this example describes the preparation of a readily collapsible thermoplastic phenolic resin with a disintegrant composition.
In the synthesis process of the common thermoplastic phenolic resin PF90, the disintegrator composition is put into a reaction kettle according to 10-50% of the resin material amount, stirred for 10-15 min, and then the resin is decompressed and dehydrated. After the resin is dehydrated, the resin is unloaded on a cooling transmission steel belt to be made into the easy-to-collapse thermoplastic phenolic resin with the crumbling agent in a sheet shape, a strip shape or a granular shape.
Example 3: this example describes the preparation of easily collapsible precoated sand with a composition of a disintegrator.
Heating 100kg of inner covering scouring sand (15Q) to 135 ℃, then discharging the sand into a balance wheel type precoated sand mixer, adding common flaky thermoplastic phenolic resin PF901.5 KGg for precoating for 30s, adding plasticizer DBP0.15kg, then mixing the sand for 20s, adding 750ml of 30% hexamethylene tetramine aqueous solution and 400ml of a disintegrator composition, then adding 0.07kg of calcium stearate, continuously mixing the sand for 30s, blowing and cooling, discharging the sand after the precoated sand is completely dispersed, and preparing the easily-disintegrated precoated sand, wherein the performance of the easily-disintegrated precoated sand is shown in the table.
Example 4: this example describes the preparation of easily collapsible precoated sand using the easily collapsible thermoplastic precoated sand of example 2.
Heating 100kg of inner covering scouring sand (15Q) to 135 ℃, discharging the sand into a balance wheel type precoated sand mixer, adding 1.5kg of the easy-collapsibility thermoplastic phenolic resin containing the crumbling agent of the invention in example 2 for precoating for 30s, adding a plasticizer DBP0.15kg and then mixing the sand for 20s, adding 750ml of 30% hexamethylene tetramine aqueous solution, then adding 0.07kg of calcium stearate, continuously mixing the sand for 30s, blowing and cooling, discharging the sand after the precoated sand is completely dispersed, and preparing the easy-collapsibility sand mixerThe performance of the easy-collapsibility precoated sand is shown in the table. Table:
| hot tensile strength Degree (Mpa) | Strength of tension at normal temperature Degree (MPa) | Melting Point C | Gas evolution (ml/g) | Collapsibility (MPa) | |
| Prior Art | 1.42 | 2.39 | 104 | 13.4 | ＞0.5 |
| Example 3 | 1.46 | 2.38 | 104 | 13.4 | 0.3 |
| Example 4 | 1.48 | 2.36 | 104 | 13.4 | 0.35 |
Claims (4)
1. A disintegrator composition characterized by: the dispersing agent consists of nitrate capable of decomposing at 400-600 ℃ and releasing oxygen, chloride capable of adjusting the decomposition temperature of the nitrate, cresol and fluorescein sodium salt serving as protective agents for thermal decomposition products of the nitrate, water and ethanol which are prepared as vectors;
① nitrate is sodium nitrate, potassium nitrate, strontium nitrate, and sodium nitrite, preferably sodium nitrate, chloride is sodium chloride, potassium chloride, preferably sodium chloride, and cresol is 2.6 di-tert-butyl-p-cresol;
②, the weight percentage of nitrate is 20-70%, the weight percentage of chloride is 0-5%, or 0%, the weight percentage of 2, 6-di-tert-butyl-p-cresol is 0-25%, or 0%, the weight percentage of sodium fluorescein is 0-1%, or 0%, the weight percentage of water is 20-70%, and the weight percentage of ethanol is 0-10%.
2. The disintegrative composition of claim 1, wherein:
①, the nitrate is sodium nitrate, the chloride is sodium chloride;
②, the nitrate accounts for 30-50% of the total weight of the dispersing agent, the 2.6 di-tert-butyl-p-cresol accounts for 0-10% of the total weight of the dispersing agent, and the sodium fluorescein salt accounts for 0-0.05% of the total weight of the dispersing agent.
3. A process for producing the disintegrative composition of claims 1 and 2, wherein: dissolving 2, 6-di-tert-p-cresol in ethanol forlater use; adding water and nitrate into a container with a stirring device, starting the stirrer, dripping the alcohol solution of 2.6 di-tert-p-cresol into the mixture after the nitrate is dissolved, then adding chloride, adding sodium fluorescein salt after the chloride is completely dissolved, and continuously stirring to prepare the collapsing agent.
4. A composition as claimed in any one of claims 1 to 2, which is directly usable for the production of a readily collapsible thermoplastic phenolic resin and for the production of a readily collapsible precoated sand.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB991201027A CN1163327C (en) | 1999-12-03 | 1999-12-03 | Composite disperser of sand in coating phenolic resin and its preparing process |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB991201027A CN1163327C (en) | 1999-12-03 | 1999-12-03 | Composite disperser of sand in coating phenolic resin and its preparing process |
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| CN1298774A true CN1298774A (en) | 2001-06-13 |
| CN1163327C CN1163327C (en) | 2004-08-25 |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100450664C (en) * | 2007-01-09 | 2009-01-14 | 辽宁福鞍铸业集团有限公司 | Production of large and super-critical steel-casting by using alkali phenolic aldehyde resin art |
| CN101222992B (en) * | 2005-07-15 | 2010-05-26 | 株式会社小松制作所 | Resin-coated sand for use in cast steel, casting mold made of the sand, steel casting casted using the casting mold |
| CN101941042A (en) * | 2010-09-03 | 2011-01-12 | 吴江市液铸液压件铸造有限公司 | Easily collapsed coated sand |
| CN102861865A (en) * | 2011-07-06 | 2013-01-09 | 三鑫重工机械有限公司 | Molding sand proportioning technology for producing large supercritical casting steel |
| CN104841871A (en) * | 2015-05-07 | 2015-08-19 | 马鞍山市恒毅机械制造有限公司 | High-quality precoated sand for making core and preparation method thereof |
| CN108971416A (en) * | 2018-09-03 | 2018-12-11 | 王韶华 | A kind of casting High-temperature-reseasyng easyng collapse precoated sand |
| CN109175217A (en) * | 2018-11-14 | 2019-01-11 | 李新忠 | A kind of cast glass sand and preparation method thereof |
| CN110267752A (en) * | 2017-02-10 | 2019-09-20 | 旭有机材株式会社 | The manufacturing method of mould material composition and the casting mold using it |
| CN110586849A (en) * | 2019-09-26 | 2019-12-20 | 宁波新天阳新材料科技有限公司 | Resin precoated sand easy to collapse |
| CN111601672A (en) * | 2018-01-16 | 2020-08-28 | 住友电木株式会社 | Phenol resin composition for forming resin-coated sand, sand core for casting, and method for producing casting |
| CN112296248A (en) * | 2020-11-03 | 2021-02-02 | 重庆长江造型材料（集团）股份有限公司 | Easily-collapsible precoated sand and preparation method thereof |
| CN117384334A (en) * | 2023-12-11 | 2024-01-12 | 山东宇世巨化工有限公司 | Easily-collapsible phenolic resin for precoated sand and preparation method thereof |
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| CN102688978A (en) * | 2012-06-26 | 2012-09-26 | 长沙南托造型材料有限公司 | Cast aluminum coated sand easily-collapsible additive, coated sand and production method of coated sand |
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1999
- 1999-12-03 CN CNB991201027A patent/CN1163327C/en not_active Expired - Lifetime
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101222992B (en) * | 2005-07-15 | 2010-05-26 | 株式会社小松制作所 | Resin-coated sand for use in cast steel, casting mold made of the sand, steel casting casted using the casting mold |
| CN100450664C (en) * | 2007-01-09 | 2009-01-14 | 辽宁福鞍铸业集团有限公司 | Production of large and super-critical steel-casting by using alkali phenolic aldehyde resin art |
| CN101941042A (en) * | 2010-09-03 | 2011-01-12 | 吴江市液铸液压件铸造有限公司 | Easily collapsed coated sand |
| CN101941042B (en) * | 2010-09-03 | 2013-01-09 | 吴江市液铸液压件铸造有限公司 | Easily collapsed coated sand |
| CN102861865A (en) * | 2011-07-06 | 2013-01-09 | 三鑫重工机械有限公司 | Molding sand proportioning technology for producing large supercritical casting steel |
| CN104841871A (en) * | 2015-05-07 | 2015-08-19 | 马鞍山市恒毅机械制造有限公司 | High-quality precoated sand for making core and preparation method thereof |
| CN110267752A (en) * | 2017-02-10 | 2019-09-20 | 旭有机材株式会社 | The manufacturing method of mould material composition and the casting mold using it |
| CN110267752B (en) * | 2017-02-10 | 2022-01-11 | 旭有机材株式会社 | Mold material composition and method for producing mold using same |
| CN111601672A (en) * | 2018-01-16 | 2020-08-28 | 住友电木株式会社 | Phenol resin composition for forming resin-coated sand, sand core for casting, and method for producing casting |
| CN108971416A (en) * | 2018-09-03 | 2018-12-11 | 王韶华 | A kind of casting High-temperature-reseasyng easyng collapse precoated sand |
| CN109175217A (en) * | 2018-11-14 | 2019-01-11 | 李新忠 | A kind of cast glass sand and preparation method thereof |
| CN110586849A (en) * | 2019-09-26 | 2019-12-20 | 宁波新天阳新材料科技有限公司 | Resin precoated sand easy to collapse |
| CN112296248A (en) * | 2020-11-03 | 2021-02-02 | 重庆长江造型材料（集团）股份有限公司 | Easily-collapsible precoated sand and preparation method thereof |
| CN112296248B (en) * | 2020-11-03 | 2022-05-31 | 重庆长江造型材料（集团）股份有限公司 | Easily-collapsible precoated sand and preparation method thereof |
| CN117384334A (en) * | 2023-12-11 | 2024-01-12 | 山东宇世巨化工有限公司 | Easily-collapsible phenolic resin for precoated sand and preparation method thereof |
| CN117384334B (en) * | 2023-12-11 | 2024-03-26 | 山东宇世巨化工有限公司 | Easily-collapsible phenolic resin for precoated sand and preparation method thereof |
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| CN1163327C (en) | 2004-08-25 |
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