Modified PEG (Polyethylene Glycol) material for casting mold

Abstract

The invention discloses a modified PEG (Polyethylene Glycol) material for a casting mold, which belongs to the technical field of casting, and is prepared by the following steps: blending polystyrene, carbon tetrachloride, tin tetrachloride, 1, 4-dichloromethoxybutane, a carbon tetrachloride mixed solution and diluted hydrochloric acid to obtain chloromethylated polystyrene; the preparation method comprises the following steps: blending chloromethylated polystyrene, toluene, hexadecyl ammonium bromide, polyethylene glycol and a sodium hydroxide solution to obtain a polystyrene grafted polyethylene glycol polymer, and uniformly dispersing polyethylene glycol, the polystyrene grafted polyethylene glycol polymer and a composite plastic brightener to obtain the modified polyethylene glycol material. The requirements for precision casting and environmental protection performance in the modern investment casting process are met through the polyethylene glycol material, the mechanical property of the material is improved through modified polyethylene glycol, and the requirements of the modern investment casting process are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of casting technology, in particular to a modified PEG material for a melting and casting mold. BACKGROUND

[0002] The lost wax method is an ancient Chinese production process that uses wax such as beeswax to make a casting model for fine carving and hot processing, thereby making a complex casting mold. In modern times, the lost wax method can present the details of metal products, which are very complex to design and difficult to manufacture, and the lost wax method can completely reproduce the appearance of the wax mold. Therefore, this method is still widely used in the fields of sculpture, jewelry processing, dentistry and industrial restoration. The lost wax method wax mold material in ancient times mainly includes beeswax, rosin, animal oil such as beef tallow, etc. In modern times, the wax mold material is further optimized, and synthetic wax or filler wax added with organic acid, polystyrene, etc. is used to improve the surface precision and strength.

[0003] Polyethylene glycol (PEG) as a water-soluble polymer material has the potential to replace traditional wax molds in theory. The traditional lost wax method needs to burn the wax mold at high temperature to form a cavity, while PEG can be dissolved and demolded by heating water, without the need for high-temperature combustion, which can simplify the process and reduce energy consumption. Moreover, the melting point of PEG can be adjusted according to the molecular weight, and the low-temperature dissolution characteristics reduce the thermal stress damage to the mold, which is suitable for precision casting requirements. In addition, the traditional wax mold needs to be demolded at high temperature, which may produce smoke or residues, while the water-soluble demolding of PEG can avoid combustion pollution and meet the trend of green manufacturing. The use of PEG demolding material can reduce the mold cleaning time and the use of chemical cleaning agents, which can further reduce the production cost. Although PEG has theoretical advantages, its practical application needs to solve problems such as material strength and mold stability, so that its mechanical properties match the casting process. In addition, some studies point out that the lubricity and thermal stability of the demolding agent directly affect the surface quality of the casting, and if the PEG is not completely dissolved, it may cause residues, affecting the precision of the casting. Therefore, it is necessary to modify PEG to make it have more excellent mechanical properties to meet the requirements of the melting and casting process. SUMMARY

[0004] The purpose of the present application is to provide a modified PEG material for a melting and casting mold, which solves the following technical problems: the demand for precision casting and environmental performance in modern melting and casting process, and the modification of polyethylene glycol to match its mechanical properties with the casting process.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A modified PEG material for a melting and casting mold, characterized in that the modified PEG material is composed of polystyrene grafted polyethylene glycol polymer and composite plastic brightener.

[0007] The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps:

[0008] The chloromethylated polystyrene, toluene, cetyl ammonium bromide, polyethylene glycol and sodium hydroxide solution are blended, the temperature is controlled at 70-80 DEG C, stirring reaction is carried out for 12-14 h, and then the product is washed, filtered, soaked with anhydrous ethanol and dried to obtain the polystyrene grafted polyethylene glycol polymer.

[0009] The mixing and adding mass ratio of the polyethylene glycol, the polystyrene grafted polyethylene glycol polymer and the composite plastic brightener is 70-80:25-35:0.3-0.8.

[0010] As a further scheme of the present application, the molecular weight of the polyethylene glycol is 1000 or 1500; and the sodium hydroxide solution is 33 wt% sodium hydroxide aqueous solution.

[0011] The adding ratio of the chloromethylated polystyrene, toluene, cetyl ammonium bromide, polyethylene glycol and sodium hydroxide solution is 1 g:35-45 mL:1-2 g:1-3 g:25-35 g.

[0012] As a further scheme of the present application, the preparation method of the chloromethylated polystyrene comprises the following steps:

[0013] The polystyrene and carbon tetrachloride are blended, and then tin tetrachloride is added at a temperature of 10-20 DEG C, and then the mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride is added dropwise, the dropwise adding time is 40 min-1 h, the reaction is carried out for 18-20 h, the product is washed with dilute hydrochloric acid, precipitated by adding anhydrous ethanol, and dried to obtain the chloromethylated polystyrene.

[0014] As a further scheme of the present application, the volume ratio of 1,4-dichloromethoxy butane and carbon tetrachloride in the mixed solution is 1:1, and the concentration of the dilute hydrochloric acid is 1 mol / L.

[0015] As a further scheme of the present application, the adding ratio of the polystyrene, carbon tetrachloride, tin tetrachloride and the mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride in the preparation method of the chloromethylated polystyrene is 1.5-2.5 g:45-55 mL:1-2 mL:15-25 mL.

[0016] As a further scheme of the present application, the composite plastic brightener comprises the following raw materials by weight: 75-85 parts by weight of modified stearic acid, 15-25 parts by weight of polyethylene polyamine, 1-2 parts by weight of antioxidant, and 0.1 part by weight of initiator.

[0017] As a further scheme of the present application: the antioxidant is a mixture of 3-(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) octadecyl ester and 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole.

[0018] The initiator is dicumyl peroxide.

[0019] As a further scheme of the present application: the preparation method of the modified stearic acid comprises the following steps:

[0020] The stearic acid, ethylene oxide and KOH are put into a high-pressure reaction kettle, the temperature is controlled at 180-200 DEG C, the pressure is controlled at 0.3-0.4 MPa, and the reaction is stirred under the nitrogen atmosphere, when the reaction kettle reaches 60-75 mg KOH / g of the reaction system, the reaction is ended, the temperature is controlled at 70-90 DEG C, the pH is adjusted to 5.0-7.0, and the modified stearic acid is obtained by decolorization.

[0021] As a further scheme of the present application: the mass ratio of the stearic acid, ethylene oxide and KOH is 40-45:93-105:0.13-0.75.

[0022] The present application has the following beneficial effects:

[0023] (1) The modified polyethylene glycol material for the melt casting mold prepared in the present application comprises polystyrene grafted polyethylene glycol polymer and composite plastic brightener; the polystyrene grafted polyethylene glycol polymer is obtained by blending chloromethylated polystyrene, toluene, cetyl ammonium bromide, polyethylene glycol and sodium hydroxide solution, wherein the chloromethylated polystyrene is obtained by mixing chloromethylated polystyrene, carbon tetrachloride, tin tetrachloride, 1,4-dichloromethoxy butane and carbon tetrachloride solution and dilute hydrochloric acid. Polystyrene is a typical linear thermoplastic polymer, the main chain of the molecule is saturated hydrocarbon, and the side group is a benzene ring, which makes the molecular chain movement difficult, and the mechanical properties are hard and brittle, non-extensible, high tensile strength, low impact strength, and easy to crack under stress. Polyethylene glycol is formed by connecting ethylene glycol molecules through ether bonds to form linear or branched polymer chains. This special molecular structure endows polyethylene glycol with good flexibility and water solubility, so that it can effectively disperse and penetrate into the material when mixed with other materials, forming a uniform network structure. This network structure can absorb and disperse energy when subjected to external force, thereby enhancing the toughness and impact resistance of the material. By grafting chloromethylated polystyrene to modify polyethylene glycol, the mechanical properties of the polyethylene glycol material are significantly improved, and the compression and bending resistance are greatly improved.

[0024] (2) The application adds a composite plastic brightener in the preparation of the modified polyethylene glycol material. The modified stearic acid is prepared by using ethylene oxide. The hydrophilic property of the -hydroxyl group at the molecular head is stronger, and the steric hindrance is small, and the diffusion rate is fast, thereby improving the efficiency of reducing the surface tension and improving the water solubility and wetting property of the modified polyethylene glycol material. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0026] The preparation method of the modified stearic acid in Example 1 includes the following steps:

[0027] Put 43 g of stearic acid, 98 g of ethylene oxide and 0.44 g of KOH into a high-pressure reaction kettle, control the temperature to be 190 DEG C and the pressure to be 0.35 MPa, stir and react under the nitrogen atmosphere, and when the reaction kettle reaches 68 mg of KOH / g of the reaction system, the reaction is ended. Control the temperature to be 80 DEG C, adjust the pH to be 6.0, and decolorize to obtain the modified stearic acid.

[0028] The composite plastic brightener in Example 2 includes the following raw materials in parts by weight: 75 parts by weight of the modified stearic acid in Example 1, 15 parts by weight of polyethylene polyamine, 1 part by weight of a mixture of 3-(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) octadecyl ester and 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, and 0.1 part by weight of dicumyl peroxide.

[0029] The composite plastic brightener in Example 3 includes the following raw materials in parts by weight: 80 parts by weight of the modified stearic acid in Example 1, 20 parts by weight of polyethylene polyamine, 1.5 parts by weight of a mixture of 3-(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) octadecyl ester and 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, and 0.1 part by weight of dicumyl peroxide.

[0030] The composite plastic brightener in Example 4 includes the following raw materials in parts by weight: 85 parts by weight of the modified stearic acid in Example 1, 25 parts by weight of polyethylene polyamine, 2 parts by weight of a mixture of 3-(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) octadecyl ester and 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, and 0.1 part by weight of dicumyl peroxide.

[0031] Example 5 A modified PEG material for a foundry mold, consisting of 70 g of polyethylene glycol 1000, 25 g of polystyrene grafted polyethylene glycol polymer, 0.5 g of the composite plastic brightener of Example 2;

[0032] The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps:

[0033] The polystyrene grafted polyethylene glycol polymer is obtained by blending 1 g of chloromethylated polystyrene, 40 mL of toluene, 1 g of cetyl ammonium bromide, 2 g of polyethylene glycol 1000, and 30 g of a 33 wt% sodium hydroxide solution, controlling the temperature at 75°C, stirring for 13 h, washing and filtering, soaking in anhydrous ethanol, and drying.

[0034] The preparation method of the chloromethylated polystyrene comprises the following steps:

[0035] The chloromethylated polystyrene is obtained by blending polystyrene and carbon tetrachloride, adding tin tetrachloride at a temperature controlled at 15°C, dropwise adding a mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride, dropwise adding time being 1 h, reacting for 20 h, washing with dilute hydrochloric acid, adding anhydrous ethanol for precipitation, and drying.

[0036] Example 6 A modified PEG material for a foundry mold, consisting of 70 g of polyethylene glycol 1000, 25 g of polystyrene grafted polyethylene glycol polymer, 0.5 g of the composite plastic brightener of Example 3;

[0037] The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps:

[0038] The polystyrene grafted polyethylene glycol polymer is obtained by blending 1 g of chloromethylated polystyrene, 40 mL of toluene, 1 g of cetyl ammonium bromide, 2 g of polyethylene glycol 1000, and 30 g of a 33 wt% sodium hydroxide solution, controlling the temperature at 75°C, stirring for 13 h, washing and filtering, soaking in anhydrous ethanol, and drying.

[0039] The preparation method of the chloromethylated polystyrene comprises the following steps:

[0040] The chloromethylated polystyrene is obtained by blending polystyrene and carbon tetrachloride, adding tin tetrachloride at a temperature controlled at 15°C, dropwise adding a mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride, dropwise adding time being 1 h, reacting for 20 h, washing with dilute hydrochloric acid, adding anhydrous ethanol for precipitation, and drying.

[0041] Example 7 A modified PEG material for a foundry mold, consisting of 70 g of polyethylene glycol 1000, 25 g of polystyrene grafted polyethylene glycol polymer, 0.5 g of the composite plastic brightener of Example 4;

[0042] The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps:

[0043] 1 g of chloromethylated polystyrene, 40 mL of toluene, 1 g of cetyl ammonium bromide, 2 g of polyethylene glycol 1000, 30 g of 33 wt% sodium hydroxide solution are blended, the temperature is controlled at 75°C, stirring is carried out for 13 h, washing and filtration are carried out, immersion in anhydrous ethanol is carried out, and drying is carried out, to obtain the polystyrene grafted polyethylene glycol polymer;

[0044] The preparation method of the chloromethylated polystyrene comprises the following steps:

[0045] Polystyrene and carbon tetrachloride are blended, tin tetrachloride is added at a temperature controlled at 15°C, a mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride is added dropwise, the dropwise adding time is 1 h, reaction is carried out for 20 h, washing is carried out with dilute hydrochloric acid, anhydrous ethanol is added for precipitation, and drying is carried out, to obtain the chloromethylated polystyrene.

[0046] Example 8 A modified PEG material for a melt-casting mold, which is composed of 80 g of polyethylene glycol 1000, 35 g of polystyrene grafted polyethylene glycol polymer, and 0.5 g of the composite plastic brightener of Example 3.

[0047] The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps:

[0048] 1 g of chloromethylated polystyrene, 45 mL of toluene, 1 g of cetyl ammonium bromide, 1 g of polyethylene glycol 1000, 25 g of 33 wt% sodium hydroxide solution are blended, the temperature is controlled at 70°C, stirring is carried out for 12 h, washing and filtration are carried out, immersion in anhydrous ethanol is carried out, and drying is carried out, to obtain the polystyrene grafted polyethylene glycol polymer;

[0049] The preparation method of the chloromethylated polystyrene comprises the following steps:

[0050] Polystyrene and carbon tetrachloride are blended, tin tetrachloride is added at a temperature controlled at 10°C, a mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride is added dropwise, the dropwise adding time is 40 min, reaction is carried out for 18 h, washing is carried out with dilute hydrochloric acid, anhydrous ethanol is added for precipitation, and drying is carried out, to obtain the chloromethylated polystyrene.

[0051] Comparative Example 1 A PEG material for a melt-casting mold, which is composed of 95 g of polyethylene glycol 1000 and 0.5 g of the composite plastic brightener of Example 3.

[0052] Comparative Example 2 A modified PEG material for a melt-casting mold, which is composed of 70 g of polyethylene glycol 1000, 25 g of polystyrene grafted polyethylene glycol polymer, and 0.5 g of the composite plastic brightener.

[0053] The composite plastic brightener comprises the following raw materials in parts by weight: 80 parts by weight of stearic acid, 20 parts by weight of polyethylene polyamine, 1.5 parts by weight of a mixture of 3-(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) octadecyl ester and 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, and 0.1 part by weight of dicumyl peroxide.

[0054] The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps:

[0055] 1g of chloromethylated polystyrene, 40mL of toluene, 1g of cetyl ammonium bromide, 2g of polyethylene glycol 1000, and 30g of 33wt% sodium hydroxide solution are blended, the temperature is controlled at 75°C, stirring is carried out for 13h, washing and filtration are carried out, immersion in anhydrous ethanol is carried out, and drying is carried out, to obtain the polystyrene grafted polyethylene glycol polymer;

[0056] The preparation method of the chloromethylated polystyrene comprises the following steps:

[0057] Polystyrene and carbon tetrachloride are blended, tin tetrachloride is added at a temperature of 15°C, a mixed solution of 1,4-dichloromethoxybutane and carbon tetrachloride is added dropwise, the dropwise adding time is 1h, reaction is carried out for 20h, washing is carried out with dilute hydrochloric acid, precipitation is carried out by adding anhydrous ethanol, and drying is carried out, to obtain the chloromethylated polystyrene.

[0058] Performance test:

[0059] (1) Bending strength and surface hardness: according to GB / T 14235.2-2018 “Test method for performance of mold material for investment casting”, the JW-1 type bending performance tester of Shanghai Metallographic Mechanical Equipment Co., Ltd. is used to detect the bending strength, and the sample size is 20mmx40mmx6mm; the surface hardness is detected at 25°C using a penetrometer, and the detection results are shown in Table 1;

[0060] (2) Compressive strength: the WE-10A type hydraulic universal testing machine of Changchun Material Testing Machine Factory is used to measure the compressive strength, and the specific method is to make the wax material into a cylinder with a bottom surface diameter of 4.5cm and a height of 9cm, polish the upper and lower surfaces of the cylinder smooth and parallel with sandpaper, and place it on the testing machine to measure the strength, and the detection results are shown in Table 1;

[0061] (3) Melting point: according to GB / T 19466.3-2004: “Differential scanning calorimetry (DSC) Part 3: Determination of melting and crystallization temperatures and heat of fusion”, the DSC25 type differential scanning calorimeter of American TA Company is used to measure the melting point of the sample, and the sample size is 3mmx3mmx2mm, and the detection results are shown in Table 1;

[0062] (4) Binder contact wetting angle: according to GB / T 14235.2-2018 "Fusion Casting Mold Material Performance Test Method", with The silica sol was used as the binder, and the sample size was 2mmx25mmx60mm. The test results are shown in Table 1.

[0063] Table 1: Performance test data statistics table of examples 5-8 and comparative examples 1-2

[0064]

[0065] As can be seen from Table 1, comparative example 1 lacks polystyrene modified material, resulting in low mechanical performance, which does not meet the conditions of fusion casting mold material. This is because polyethylene glycol is connected by ether bonds between ethylene glycol molecules to form linear or branched polymer chains, so that polyethylene glycol is physically soft and tough, with low bending and compression strength. Comparative example 2 lacks modified stearic acid, resulting in reduced lubricity. This is because the hydroxyl group of the molecular head of the stearic acid modified by ethylene oxide is more hydrophilic, and the steric hindrance is small, the diffusion rate is fast, and the surface tension is reduced.

[0066] The above describes one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made according to the scope of the present application should still belong to the scope of the present application.

Claims

1. A modified PEG material for a foundry mold, characterized by, The modified PEG material is composed of polyethylene glycol, polystyrene grafted polyethylene glycol polymer and composite plastic brightener. The preparation method of the polystyrene grafted polyethylene glycol polymer comprises the following steps: The chloromethylated polystyrene, toluene, cetyl ammonium bromide, polyethylene glycol and sodium hydroxide solution are blended, the temperature is controlled at 70-80 DEG C, and stirring reaction is carried out for 12-14 h, then washing, filtering, soaking in anhydrous ethanol and drying are carried out to obtain the polystyrene grafted polyethylene glycol polymer. The mixing and adding mass ratio of the polyethylene glycol, polystyrene grafted polyethylene glycol polymer and composite plastic brightener is 70-80:25-35:0.3-0.

8.

2. A modified PEG material for a foundry mold according to claim 1, wherein, The polyethylene glycol has a molecular weight of 1000 or 1500; and the sodium hydroxide solution is 33 wt% sodium hydroxide aqueous solution. The adding ratio of the chloromethylated polystyrene, toluene, cetyl ammonium bromide, polyethylene glycol and sodium hydroxide solution is 1 g:35-45 mL:1-2 g:1-3 g:25-35 g.

3. The modified PEG material for a foundry mold according to claim 1, wherein The preparation method of the chloromethylated polystyrene comprises the following steps: The polystyrene and carbon tetrachloride are blended, the temperature is controlled at 10-20 DEG C, tin tetrachloride is added, the mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride is added dropwise, the dropwise adding time is 40 min-1 h, and the reaction is carried out for 18-20 h, then washing with dilute hydrochloric acid, adding anhydrous ethanol for precipitation and drying are carried out to obtain the chloromethylated polystyrene.

4. A modified PEG material for a foundry mold according to claim 5, wherein, The volume ratio of 1,4-dichloromethoxy butane and carbon tetrachloride in the mixed solution is 1:1, and the concentration of the dilute hydrochloric acid is 1 mol / L.

5. A modified PEG material for a foundry mold according to claim 5, wherein, The adding ratio of the polystyrene, carbon tetrachloride, tin tetrachloride and the mixed solution of 1,4-dichloromethoxy butane and carbon tetrachloride in the preparation method of the chloromethylated polystyrene is 1.5-2.5 g:45-55 mL:1-2 mL:15-25 mL.

6. The modified PEG material for a foundry mold according to claim 1, wherein The composite plastic brightener comprises the following raw materials by weight: 75-85 parts of modified stearic acid, 15-25 parts of polyethylene polyamine, 1-2 parts of antioxidant and 0.1 part of initiator.

7. The modified PEG material for a foundry mold according to claim 1, wherein The antioxidant is a mixture of 3-(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) octadecyl ester and 2-(2-hydroxy-3-tert-butyl-5-methyl phenyl)-5-chlorobenzotriazole; The initiator is dicumyl peroxide.

8. The modified PEG material for a foundry mold according to claim 1, wherein The preparation method of the modified stearic acid comprises the following steps: The stearic acid, ethylene oxide and KOH are put into a high-pressure reaction kettle, the temperature is controlled at 180-200 DEG C, the pressure is controlled at 0.3-0.4 MPa, and stirring reaction is carried out under nitrogen atmosphere, when the reaction kettle reaches 60-75 mg KOH / g of the reaction system, the reaction is ended, the temperature is controlled at 70-90 DEG C, pH is adjusted to 5.0-7.0, and decolorization is carried out to obtain the modified stearic acid.

9. A modified PEG material for a foundry mold according to claim 8, wherein, The adding mass ratio of the stearic acid, ethylene oxide and KOH is 40-45:93-105:0.13-0.75.

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