CN113020538A - Water-soluble core mold material and preparation method thereof - Google Patents
Water-soluble core mold material and preparation method thereof Download PDFInfo
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- CN113020538A CN113020538A CN202110320902.3A CN202110320902A CN113020538A CN 113020538 A CN113020538 A CN 113020538A CN 202110320902 A CN202110320902 A CN 202110320902A CN 113020538 A CN113020538 A CN 113020538A
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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
- B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
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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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- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
The invention discloses a water-soluble core mould material and a preparation method thereof, wherein the main raw materials of the water-soluble core mould material comprise a water-soluble adhesive, graphite, a compatibilizer and chopped fibers, and the weight ratio of each component is (10-30): 100: (0.5-1): (1-5), wherein the water-soluble adhesive is obtained by taking polyvinylpyrrolidone as a main adhesive and adding a low-melting-point alcohol plasticizer, a polar copolymer and a polar wax. The invention reduces the viscosity and improves the lubricating property, the strength and the toughness of the polyvinylpyrrolidone by modifying the polyvinylpyrrolidone. The inorganic filler graphite is subjected to compatibilization and dispersion by adopting the compatibilizer, the graphite filler is fully dispersed in the water-soluble adhesive, the thermal stability, the thermal conductivity and the strength of the water-soluble core mold material are improved, and the water-soluble core mold material can be applied to preparation of composite material members with special structures and difficult demolding.
Description
Technical Field
The invention relates to the field of composite material members, in particular to a water-soluble core mold material and a preparation method thereof.
Background
With the rapid development of modern industrial technology, particularly the rapid advance of aerospace industry, the shape of a casting is increasingly complex; the requirements on the complexity, the dimensional precision, the surface smoothness and the like of the inner cavity of the water-soluble core mould are higher and higher, so that the water-soluble core mould material is promoted to be produced. The water-soluble core mould material is a composite material which is made up by using various water-soluble adhesives to bind some fillers together, and according to the requirements of use making them into the product with a certain form, and in the range of application temp. it possesses a certain mechanical property and can retain its form, and when demoulding, it uses the solvent of water, etc. to make it disperse, then demoulding so as to obtain the invented product. The method has the advantages of high forming precision, low cost, high efficiency, easy demoulding and the like, and is widely applied to various casting and composite material manufacturing industries with strict requirements on high standards.
Water-soluble core materials have since the advent undergone various stages of development, primarily around the development of water-soluble adhesives throughout their development. Although there are many different kinds of water-soluble adhesives, polyethylene glycol, polyvinyl alcohol, polyacrylate organic polymer adhesives and natural polymer compounds are mainly used to meet the requirements of use. The starch derivative can improve the water solubility of the core mold material on the basis of ensuring the mechanical property of the core mold due to the unique structural characteristics of the starch derivative. However, due to the defects of the adhesives, such as low bonding strength, difficulty in meeting the production requirements of water solubility, complex water-soluble treatment process, high cost and the like, the strict requirements of the adhesives for the water-soluble core mold material in various fields at present are difficult to meet, so that the application range of the water-soluble core mold material is limited.
The improvement of the water-soluble core material has been mainly made around the development of an adhesive to be used, and the attention on the filler to be used for the core material has not been sufficient. This also limits the development of mandrel materials to some extent. The traditional filler has the problems of high density, irregular shape, easy stress concentration and the like, so that the use requirements of some high-performance core die materials are difficult to meet. The selection of a proper water-soluble adhesive and a filler matched with the adhesive to manufacture the water-soluble core mold material is a main development direction in the future.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a water-soluble core mould material and a preparation method thereof.
The technical scheme adopted by the invention is as follows:
the water-soluble core mold material is prepared from a water-soluble adhesive, graphite, a compatibilizer and chopped fibers in a weight ratio of (10-30): 100: (0.5-1): (1-5); the water-soluble adhesive is prepared from polyvinylpyrrolidone, an alcohol plasticizer, a polar copolymer and polar wax according to the proportion of 100: (15-35): (10-20): (1-5) blending.
The water-soluble adhesive is prepared from polyvinylpyrrolidone, alcohol plasticizer, polar copolymer and polar wax according to the proportion of 100: (15-35): (10-20): (1-5) blending to obtain; polyvinylpyrrolidone (PVP) is a water-soluble high-molecular compound, PVP is a green high-molecular fine chemical with excellent performance, and has the general properties of the water-soluble high-molecular compound, such as colloid protection, film-forming property, cohesiveness, hygroscopicity, solubilization or coacervation, coordination capacity with certain compounds and the like, and good thermal stability, but is most characterized by excellent solubility and physiological compatibility. The low-molecular-weight polyethylene glycol has a lower melting point and a flexible chain structure, so that the melting point of PVP is reduced, and the toughness is improved. The addition of the polar wax reduces the viscosity of PVP and improves the strength of the PVP, and the addition of the polar copolymer greatly improves the mild degree and toughness of the PVP.
Preferably, the water-soluble adhesive is prepared from polyvinylpyrrolidone, alcohol plasticizer, polar copolymer and polar wax according to the weight ratio of 100: (15-35): (10-20): (1-5) blending.
Preferably, the alcohol plasticizer is liquid polyethylene glycol with low molecular weight, specifically any one of polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600 and polyethylene glycol 800, and the most preferred alcohol plasticizer is polyethylene glycol 600.
Preferably, the polar copolymer is any one of polyvinyl formal, polyvinyl butyral, and water-soluble polyurethane.
Preferably, the polar wax is a compound having alcohol, acid, ester or amide functionality, in particular any one of oleamide, stearamide, stearic acid, stearate esters, ethoxylated fatty alcohols.
The preferred graphite is spherical graphite, the particle size of the graphite is more than 90wt% and less than 40 μm, and the specific surface area is 4.5 square meters per gram. The spherical graphite of the invention is a graphite product with different fineness and similar to an ellipsoid shape, which is produced by taking high-quality high-carbon natural crystalline flake graphite as a raw material and carrying out ball milling treatment on the surface of the graphite by adopting an advanced processing technology. The invention adopts spherical graphite as the filler, and the spherical filler is different from irregular-shaped or angular granules, so that the phenomenon of stress concentration for reducing the mechanical property of the composite material can be avoided. The spherical graphite has the particle size of more than 90wt% and less than 40 mu m, the specific surface area of 4.5 square meters per gram, small density, light weight, higher heat conductivity and surface area and great improvement on the thermal stability of a core mold material. The high mechanical property of the spherical graphite filler can greatly improve the strength of the core mold material.
Preferably, the compatibilizer is lignosulfonate, and the chopped fibers are polypropylene chopped fibers or polyester chopped fibers with the length of 5-10 mm. The addition of the chopped fibers and the graphite filler form a synergistic effect, so that the strength and the toughness of the core mold material are further improved.
The preparation method of the water-soluble core mold material comprises the following steps:
1) preparation of Water-soluble core Adhesives
Heating 100 parts of polyvinylpyrrolidone to a molten state according to the weight ratio, and then respectively adding 15-35 parts of alcohol plasticizer, 10-20 parts of polar copolymer and 1-5 parts of polar wax for uniformly blending to obtain the water-soluble adhesive;
2) preparation of water-soluble core mould material
In a reactor, the water-soluble adhesive, graphite, the compatibilizer and the chopped fiber are mixed according to the weight ratio of (10-30): 100: (0.5-1): and (1-5) adding, heating and uniformly mixing to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, and cooling and demolding to obtain the water-soluble core mold material.
Preferably, the melting temperature of the step 1) is 130-150 ℃, and the blending time is 30 min.
Preferably, the heating temperature of the step 2) is 175-195 ℃, and the blending time is 2-3 hours.
Compared with the prior art, the invention has the beneficial effects that
The invention reduces the viscosity and improves the lubricating property, the strength and the toughness of the polyvinylpyrrolidone by modifying the polyvinylpyrrolidone. The inorganic filler graphite is subjected to compatibilization and dispersion by adopting the compatibilizer, the graphite filler is fully dispersed in the water-soluble adhesive, the thermal stability, the thermal conductivity and the strength of the water-soluble core mold material are improved, and the water-soluble core mold material can be applied to preparation of composite material members with special structures and difficult demolding.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1:
preparation of the water-soluble adhesive: heating 100 parts of polyvinylpyrrolidone to 130 ℃, and then respectively adding 15 parts of polyethylene glycol 600, 10 parts of polyvinyl formal and 1 part of stearic acid amide to uniformly blend to obtain the water-soluble adhesive;
preparing a water-soluble core mold material: adding 10 parts of the prepared water-soluble adhesive into a reactor, heating to 195 ℃, then respectively stirring 100 parts of spherical graphite, 0.5 part of lignosulfonate and 1 part of polypropylene chopped fiber with the length of 5mm for 3 hours until uniformly mixing to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, cooling and demolding to obtain the water-soluble core mold material.
Example 2:
preparation of the water-soluble adhesive: heating 100 parts of polyvinylpyrrolidone to 140 ℃, and then respectively adding 20 parts of polyethylene glycol 600, 15 parts of polyvinyl formal and 3 parts of stearic acid for uniformly blending to obtain the water-soluble adhesive;
preparing a water-soluble core mold material: adding 15 parts of the prepared water-soluble adhesive into a reactor, heating to 195 ℃, then respectively stirring 100 parts of spherical graphite, 1 part of lignosulfonate and 2 parts of polyester chopped fiber with the length of 6mm for 3 hours until the spherical graphite, the lignosulfonate and the polyester chopped fiber are uniformly mixed to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, cooling and demolding to obtain the water-soluble core mold material
Example 3:
preparation of the water-soluble adhesive: heating 100 parts of polyvinylpyrrolidone to 150 ℃, and then respectively adding 25 parts of polyethylene glycol 600, 20 parts of polyvinyl butyral and 5 parts of oleamide for uniformly blending to obtain the water-soluble adhesive;
preparing a water-soluble core mold material: adding 20 parts of the prepared water-soluble adhesive into a reactor, heating to 185 ℃, then respectively stirring 100 parts of spherical graphite, 0.75 part of lignosulfonate and 4 parts of polypropylene chopped fibers with the length of 7mm for 2.5 hours until the spherical graphite, the lignosulfonate and the polypropylene chopped fibers are uniformly mixed to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, and cooling and demolding to obtain the water-soluble core mold material.
Example 4:
preparation of the water-soluble adhesive: heating 100 parts of polyvinylpyrrolidone to 140 ℃, and then respectively adding 30 parts of polyethylene glycol 600, 15 parts of water-soluble polyurethane and 4 parts of stearate for uniformly blending to obtain the water-soluble adhesive;
preparing a water-soluble core mold material: adding 25 parts of the prepared water-soluble adhesive into a reactor, heating to 175 ℃, then respectively stirring 100 parts of spherical graphite, 1 part of lignosulfonate and 3 parts of polypropylene chopped fibers with the length of 9mm for 2 hours until uniformly mixing to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, cooling and demolding to obtain the water-soluble core mold material.
Example 5:
preparation of the water-soluble adhesive: heating 100 parts of polyvinylpyrrolidone to 130 ℃, and then respectively adding 35 parts of polyethylene glycol 600, 10 parts of polyvinyl butyral and 2 parts of stearic amide for uniformly blending to obtain the water-soluble adhesive;
preparing a water-soluble core mold material: adding 30 parts of the prepared water-soluble adhesive into a reactor, heating to 175 ℃, then respectively stirring 100 parts of spherical graphite, 0.5 part of lignosulfonate and 5 parts of polyester chopped fiber with the length of 10mm for 2 hours until uniformly mixing to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, cooling and demolding to obtain the water-soluble core mold material.
Comparative example 1:
adding 20 parts of polyvinylpyrrolidone into a reactor, heating to 185 ℃, then respectively stirring 100 parts of spherical graphite, 0.75 part of lignosulfonate and 4 parts of polypropylene chopped fibers with the length of 7mm for 2.5 hours until the spherical graphite, the lignosulfonate and the polypropylene chopped fibers are uniformly mixed to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, cooling and demolding to obtain the water-soluble core mold material.
Comparative example 2:
comparative example 2 differs from example 3 in that: 100 parts of quartz sand is adopted to replace the spherical graphite;
heating 100 parts of polyvinylpyrrolidone to 150 ℃, and then respectively adding 25 parts of polyethylene glycol 600, 20 parts of polyvinyl butyral and 5 parts of oleamide for uniformly blending to obtain the water-soluble adhesive;
adding 20 parts of the prepared water-soluble adhesive into a reactor, heating to 185 ℃, then respectively stirring 100 parts of quartz sand, 0.75 part of lignosulfonate and 4 parts of polypropylene chopped fibers with the length of 7mm for 2.5 hours until the materials are uniformly mixed to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, cooling and demolding to obtain the water-soluble core mold material.
Comparative example 3:
comparative example 3 differs from example 3 in that: polyethylene glycol 600 is not added in the preparation process of the water-soluble adhesive;
comparative example 4:
comparative example 4 differs from example 3 in that: the length of the polypropylene fiber used in the preparation process of the water-soluble core mold material is 25 mm;
and (3) performance testing: density: for each example, 10 groups of water-soluble core mold materials (40mm × 40mm × 50mm) were weighed, and their densities were averaged to obtain an average density;
mass water dissolution rate: putting the water-soluble core mold material (40mm multiplied by 50mm) in static normal-temperature (25 ℃) tap water until the water-soluble core mold material is completely dissolved;
compression strength, bending strength: testing by using GB/T17671-1999 standard;
coefficient of thermal expansion: testing by adopting a GB/T1036-2008 standard;
the results of the performance tests of examples 1-5 and comparative examples 1-4 according to the present invention are as follows:
finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.
Claims (10)
1. The water-soluble core mold material is characterized by comprising the following components in parts by weight: 100: (0.5-1): (1-5); the water-soluble adhesive is prepared from polyvinylpyrrolidone, an alcohol plasticizer, a polar copolymer and polar wax according to the proportion of 100: (15-35): (10-20): (1-5) blending.
2. The water soluble core plug material of claim 1, wherein the water soluble adhesive is prepared from polyvinylpyrrolidone, alcohol plasticizer, polar copolymer, polar wax in a ratio of 100: 20: 15: 3, blending to obtain the product.
3. The water soluble core mold material of claim 1, wherein the alcohol plasticizer is any one of polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, and polyethylene glycol 800.
4. The water soluble core mold material as claimed in claim 1, wherein the polar copolymer is any one of polyvinyl formal, polyvinyl butyral, and water soluble polyurethane.
5. The water soluble core plug material of claim 1, wherein the polar wax is any one of oleamide, stearamide, stearic acid, stearate esters, ethoxylated fatty alcohols.
6. The water-soluble core mold material according to claim 1, wherein the graphite is spherical graphite, the graphite has a particle size of 90wt% or more and less than 40 μm, and a specific surface area of 4.5 square meters per gram.
7. The water soluble core plug material of claim 1, wherein the compatibilizer is lignosulfonate; the chopped fiber is polypropylene chopped fiber or polyester chopped fiber with the length of 5-10 mm.
8. The method of making a water soluble core plug material as claimed in any one of claims 1 to 7, comprising the steps of:
1) preparation of Water-soluble core Adhesives
Heating 100 parts of polyvinylpyrrolidone to a molten state according to the weight ratio, and then respectively adding 15-35 parts of alcohol plasticizer, 10-20 parts of polar copolymer and 1-5 parts of polar wax for uniformly blending to obtain the water-soluble adhesive;
2) preparation of water-soluble core mould material
In a reactor, the water-soluble adhesive, graphite, a compatibilizer and chopped fibers are mixed according to the weight ratio of (10-30): 100: (0.5-1): and (1-5) adding, heating and uniformly mixing to obtain a core mold material mixture, melting and shaping the core mold material mixture in a mold, and cooling and demolding to obtain the water-soluble core mold material.
9. The method for preparing a water-soluble core mold material as claimed in claim 8, wherein the melting temperature in the step 1) is 130-150 ℃ and the blending time is 30 min.
10. The method for preparing a water-soluble core mold material as claimed in claim 8, wherein the heating temperature in the step 2) is 175-195 ℃ and the blending time is 2-3 hours.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114043650A (en) * | 2021-12-02 | 2022-02-15 | 上海新旺科技有限公司 | Water-soluble core mould |
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| CN102815889A (en) * | 2012-08-28 | 2012-12-12 | 西安航天复合材料研究所 | Water-soluble core model material |
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| CN108864994A (en) * | 2017-05-16 | 2018-11-23 | 航天特种材料及工艺技术研究所 | A kind of solubility bonding agent, soluble core model and preparation method |
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| CN114043650A (en) * | 2021-12-02 | 2022-02-15 | 上海新旺科技有限公司 | Water-soluble core mould |
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