Aluminum alloy 3D printing photosensitive resin molding investment casting coating and preparation method thereof

Abstract

The invention provides an aluminum alloy 3D printing photosensitive resin molding investment casting coating which comprises the following components in parts by weight: 7-10 parts of active magnesium oxide, 16-20 parts of silica sol with the solid content of 20%-32%, 12-18 parts of bentonite, 2-6 parts of cellulose and 16-30 parts of epoxy resin. The invention further provides a preparation method of the coating. The coating provided by the invention is beneficial to improvement of fire resistance, crack resistance and adhesive force.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to an aluminum alloy 3D printing photosensitive resin mold investment casting coating and a preparation method thereof. Background Art

[0002] Investment casting is an advanced near-net-shape molding process that can produce precision and complex castings of various alloys. The castings are close to the final shape and size of the parts and can be used directly without machining or with minimal machining. Investment casting usually uses fusible materials to make a model, and then applies a refractory coating on the surface of the model. After the coating hardens and dries, the model is heated to melt the mold material to form a hollow shell. After the hollow shell is sintered at high temperature, liquid metal is poured into it to cast metal castings.

[0003] With the development of 3D printing technology, photosensitive resin can be used as model material. Due to the molecular characteristics of photosensitive resin, the adhesion of existing refractory coatings does not meet the use requirements. In addition, existing refractory materials crack after high-temperature sintering, which affects the molding quality of castings. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the object of the present invention is to provide an aluminum alloy 3D printing photosensitive resin mold investment casting coating that is beneficial to improving the fire resistance, crack resistance and adhesion.

[0005] The present application also provides a method for preparing the coating.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: A photosensitive resin mold investment casting coating for aluminum alloy 3D printing comprises, by weight, 7-10 parts of active magnesium oxide, 16-20 parts of silica sol, wherein the solid content of the silica sol is 20%-32%, 12-18 parts of bentonite, 2-6 parts of cellulose and 16-30 parts of epoxy resin.

[0007] In some possible implementations, by weight, the ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.2-1.5:2.5-2.6.

[0008] In some possible implementations, the ratio of the epoxy resin to the cellulose is 3-7:1 by weight.

[0009] In some possible implementations, the amount of the silica sol is 17-18 parts.

[0010] In some possible implementations, the amount of bentonite is 12-16 parts.

[0011] In some possible implementations, the epoxy resin accounts for 18-25 parts.

[0012] In some possible implementations, the epoxy resin is selected from one of a glycidyl ether epoxy resin, a glycidyl ester epoxy resin, or a glycidyl amine epoxy resin.

[0013] In some possible implementations, the coating further comprises 1-2 parts of an auxiliary agent by weight, wherein the auxiliary agent comprises a defoaming agent.

[0014] The present application also provides a method for preparing an aluminum alloy 3D printing photosensitive resin mold investment casting coating, the preparation method using the components of the coating as described, the preparation method comprising the following steps: Mixing active magnesium oxide into silica sol according to a set ratio to obtain a first mixture; mixing bentonite and cellulose into epoxy resin in a set ratio to obtain a second mixture; The first mixture is mixed into the second mixture to obtain a coating.

[0015] In some possible implementations, the mixing temperature of the first mixture is 20-40°C, and the mixing speed is 1500-2000 rpm, the mixing temperature of the second mixture is 20-40°C, and the mixing speed is 1000-3000 rpm, and the mixing temperature of the coating is 20-40°C, and the mixing speed is 2000-3000 rpm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the present application, the fire resistance of the coating is improved by the synergistic effect of activated magnesium oxide, silica sol and bentonite. In addition, cellulose assists the dispersion of silica in activated magnesium oxide, bentonite and silica sol into the epoxy resin system through polar groups such as hydroxyl groups, thereby further improving the fire resistance of the coating. In addition, the dispersion of the above-mentioned refractory particles cooperates with cellulose and epoxy resin to improve the crack resistance and adhesion of the coating, so that the coating of the present application can be used in the coating of aluminum alloy 3D printing photosensitive resin mold investment casting.

[0017] The present invention is further described in detail below in conjunction with specific implementation modes. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0020] Some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0021] An embodiment of the present application provides an aluminum alloy 3D printing photosensitive resin mold investment casting coating, which includes, by weight, 7-10 parts of active magnesium oxide, 16-20 parts of silica sol, wherein the solid content of the silica sol is 20%-32%, 12-18 parts of bentonite, 2-6 parts of cellulose and 16-30 parts of epoxy resin.

[0022] In some embodiments, by weight, the ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.2-1.5:2.5-2.6. The selection of this ratio is conducive to regulating the stacking distribution density between the refractory additives, thereby further improving the synergistic effect between the refractory additives, thereby further improving the refractory.

[0023] In some embodiments, the epoxy resin: cellulose is 3-7: 1 by weight. The selection of this ratio is conducive to further improving the crack resistance and adhesion of the coating, and the selection of the ratio in coordination with the fire-resistant additive is conducive to further improving the fire resistance of the coating.

[0024] In some embodiments, the amount of the silica sol is 17-18 parts.

[0025] In some embodiments, the bentonite is present in an amount of 12-16 parts.

[0026] In some embodiments, the epoxy resin is present in an amount of 18-25 parts.

[0027] Further reduction of the above-mentioned number of parts is beneficial to adjusting the viscosity of the coating system for construction, and is also beneficial to adjusting the dispersibility of the fire-resistant additive to further improve the fire resistance.

[0028] In some embodiments, the epoxy resin is selected from one of glycidyl ether epoxy resin, glycidyl ester epoxy resin or glycidyl amine epoxy resin. The specific type of the above epoxy resin is beneficial to strengthen the adhesion of the epoxy resin due to the introduction of polar groups, and is also beneficial to assist in the dispersion of fillers in the epoxy resin, such as cellulose, bentonite, silicon dioxide and active magnesium oxide, thereby further improving the fire resistance and crack resistance of the coating.

[0029] In another embodiment, the epoxy resin may be a cycloaliphatic epoxy resin or a linear aliphatic epoxy resin.

[0030] In some embodiments, the coating further comprises 1-2 parts of an auxiliary agent by weight, wherein the auxiliary agent comprises a defoamer to eliminate bubbles in the coating. Exemplarily, the defoamer may comprise a waterborne epoxy resin defoamer.

[0031] In the present application, the fire resistance of the coating is improved by the synergistic effect of activated magnesium oxide, silica sol and bentonite. In addition, cellulose assists the dispersion of silica in activated magnesium oxide, bentonite and silica sol into the epoxy resin system through polar groups such as hydroxyl groups, thereby further improving the fire resistance of the coating. In addition, the dispersion of the above-mentioned refractory particles cooperates with cellulose and epoxy resin to improve the crack resistance and adhesion of the coating, so that the coating of the present application can be used in the coating of aluminum alloy 3D printing photosensitive resin mold investment casting.

[0032] Another embodiment of the present application further provides a method for preparing an aluminum alloy 3D printing photosensitive resin mold investment casting coating, the preparation method adopts the components of the coating of any of the above embodiments, therefore, the proportion selection of each component and the specific type selection are not repeated, the preparation method comprises the following steps: Active magnesium oxide is mixed into silica sol according to a set ratio to obtain a first mixture.

[0033] In some embodiments, the mixing temperature of the first mixture is 20-40°C, and the mixing speed is 1500-2000 rpm. Exemplarily, the mixing speed can be 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm or 2000 rpm and the range between the above values. Exemplarily, the mixing temperature can be 20°C, 25°C, 30°C, 35°C or 40°C and the range between the above values. The selection of the above speed and temperature is to ensure the mixed dispersibility of the active magnesium oxide.

[0034] Bentonite and cellulose are mixed into epoxy resin in a set ratio to obtain a second mixture.

[0035] In some embodiments, the mixing temperature for obtaining the second mixture is 20-40°C, and the mixing speed is 1000-3000 rpm. Exemplarily, the mixing speed can be 1000 rpm, 1500 rpm, 1700 rpm, 1800 rpm, 1900 rpm, 2000 rpm, 2500 rpm or 3000 rpm and the range between the above values. Exemplarily, the mixing temperature can be 20°C, 25°C, 30°C, 35°C or 40°C and the range between the above values. The selection of the above speed and temperature is to ensure the mixing dispersibility of bentonite and cellulose.

[0036] The first mixture is mixed into the second mixture to obtain a coating.

[0037] In some embodiments, the mixing temperature for obtaining the coating is 20-40°C, and the mixing speed is 2000-3000 rev / min. Exemplarily, the mixing speed can be 2000 rev / min, 2100 rev / min, 2200 rev / min, 2300 rev / min, 2400 rev / min, 2500 rev / min, 2600 rev / min, 2700 rev / min, 2800 rev / min, 2900 rev / min or 3000 rev / min and the range between the above values. Exemplarily, the mixing temperature can be 20°C, 25°C, 30°C, 35°C or 40°C and the range between the above values. The selection of the above speed and temperature is to ensure the mixed dispersibility of the refractory filler. The mixing speed can fluctuate within a certain range according to the stirring situation.

[0038] The above materials can be mixed by a high-speed shearing machine. In specific use, the mixed paint can be loaded into a paint spray gun, vibrated evenly, and then sprayed on a 3D printed photosensitive resin model.

[0039] Specific: Embodiment 1: A 3D printing photosensitive resin mold investment casting coating for aluminum alloy includes, by weight, 7 parts of active magnesium oxide (Zehui magnesium base, ZH-M600), 20 parts of silica sol (Huit Research and Development Company, HS-830A), the solid content of the silica sol is 30% (average value), 12 parts of bentonite (sodium bentonite, Dongguan Ruiheng Mineral Products Co., Ltd.), 4 parts of cellulose (sigma-AIdrich, S6790), 16 parts of epoxy resin and 1 part of defoamer (water-based epoxy resin defoamer, Guangzhou Yangshi Chemical Technology Co., Ltd., YS-T118). The ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.16:2. The average particle size of the active magnesium oxide is 1um, and the average particle size of the bentonite is 5um. The ratio of the epoxy resin: the cellulose is 4:1. The epoxy resin is a glycidyl ether epoxy resin, specifically tetraphenol ethane tetraglycidyl ether epoxy resin (Wengjiang reagent-PA40079).

[0040] The specific preparation method is: Active magnesium oxide is mixed into silica sol according to a set ratio to obtain a first mixture, wherein the mixing temperature of the first mixture is 30° C. and the mixing speed is 1800-2000 rpm.

[0041] Mixing bentonite and cellulose into epoxy resin according to a set ratio to obtain a second mixture, wherein the mixing temperature of the second mixture is 30° C. and the mixing speed is 2400-2500 rpm; The first mixture is mixed into the second mixture to obtain a coating, wherein the mixing temperature of the coating is 30° C. and the mixing speed is 2900-3000 rpm.

[0042] Embodiment 2: The difference from Example 1 is that, by weight, the coating includes 10 parts of active magnesium oxide, 16 parts of silica sol, 18 parts of bentonite, 2 parts of cellulose, 30 parts of epoxy resin and 1 part of defoamer. The ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:2.1:3.8. The ratio of the epoxy resin: the cellulose is 15:1. The epoxy resin is a glycidyl ester epoxy resin (4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester epoxy resin, TDE-85, Guangzhou Xian'an Chemical Co., Ltd.).

[0043] The specific preparation method is: Active magnesium oxide is mixed into silica sol according to a set ratio to obtain a first mixture, wherein the mixing temperature of the first mixture is 25° C. and the mixing speed is 1900-2000 rpm.

[0044] Mixing bentonite and cellulose into epoxy resin according to a set ratio to obtain a second mixture, wherein the mixing temperature of the second mixture is 25° C. and the mixing speed is 2900-3000 rpm; The first mixture is mixed into the second mixture to obtain a coating, wherein the mixing temperature of the coating is 25° C. and the mixing speed is 2900-3000 rpm.

[0045] Embodiment 3: The difference from Example 1 is that, by weight, the coating includes 9 parts of active magnesium oxide, 19 parts of silica sol, 17 parts of bentonite, 5 parts of cellulose, 26 parts of epoxy resin and 2 parts of defoamer. The ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.58:2.98. The ratio of the epoxy resin: the cellulose is 5.2:1. The epoxy resin is a glycidylamine epoxy resin (4,4-diaminodiphenylmethane tetraglycidylamine epoxy resin, Huineng-AG80).

[0046] The specific preparation method is: Active magnesium oxide is mixed into silica sol according to a set ratio to obtain a first mixture, wherein the mixing temperature of the first mixture is 40° C. and the mixing speed is 1500-1600 rpm.

[0047] Mixing bentonite and cellulose into epoxy resin according to a set ratio to obtain a second mixture, wherein the mixing temperature of the second mixture is 40° C. and the mixing speed is 1000-1200 rpm; The first mixture is mixed into the second mixture to obtain a coating, wherein the mixing temperature of the coating is 40° C. and the mixing speed is 2100-2200 rpm.

[0048] Embodiment 4: The difference from Example 1 is that the weight proportion of the silica sol is 17 parts, the weight proportion of the active magnesium oxide is 7.65 parts, the weight proportion of the bentonite is 12.75 parts, and the ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.5:2.5.

[0049] Embodiment 5: The difference from Example 1 is that the weight proportion of the active magnesium oxide is 7.2 parts, the weight proportion of the bentonite is 15.6 parts, and the ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.2:2.6.

[0050] Embodiment 6: The difference from Example 1 is that the weight proportion of the silica sol is 18 parts, the weight proportion of the active magnesium oxide is 7.56 parts, the weight proportion of the bentonite is 13.5 parts, and the ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.4:2.5.

[0051] Embodiment 7: The difference from Example 6 is that the weight proportion of the cellulose is 4.2 parts, the weight proportion of the epoxy resin is 29.7 parts, and the ratio of the epoxy resin to the cellulose is 7:1.

[0052] Embodiment 8: The difference from Example 6 is that the weight proportion of the cellulose is 6 parts, the weight proportion of the epoxy resin is 18 parts, and the ratio of the epoxy resin to the cellulose is 3:1. Embodiment 9: The difference from Example 6 is that the weight proportion of the cellulose is 5 parts, the weight proportion of the epoxy resin is 25 parts, and the ratio of the epoxy resin to the cellulose is 5:1.

[0053] Comparative Example 1: The difference from Example 1 is that the coating lacks active magnesium oxide. During preparation, silica sol is mixed into the mixed bentonite, cellulose and epoxy resin. The mixing conditions are the same as those in the second and third steps of Example 1.

[0054] Comparative Example 2: The difference from Example 1 is that the coating lacks bentonite. During the preparation, only cellulose is mixed into the epoxy resin, and other conditions or steps remain unchanged.

[0055] Comparative Example 3: The difference from Example 1 is that the coating lacks silica sol, and during preparation, active magnesium oxide is mixed into the mixed bentonite, cellulose and epoxy resin. The mixing conditions are the same as those in the second and third steps of Example 1.

[0056] Comparative Example 4: The difference from Example 1 is that the coating lacks cellulose. During the preparation, in the second step, bentonite is mixed into the epoxy resin, and the other operating steps and conditions remain unchanged.

[0057] This application tests the performance of the coating using the following standards.

[0058] 1. Fire resistance: Test the fire resistance limit of the coating in accordance with the national standard GB / T 9978 to test the maximum temperature that the coating can withstand.

[0059] 2. Crack resistance: The coating is applied on a photosensitive resin plate and cured to prepare a sample. The sample is placed in a high-temperature tensile testing machine for tensile testing to determine the elongation at break. The test temperature is 750°C.

[0060] 3. Adhesion: The pull-off method is used for testing. Specifically, the test sample is applied to a flat plate with a consistent surface structure (the material of the flat plate is photosensitive resin) with a uniform thickness. After the coating system is dried or cured, it is placed in a high-temperature furnace and baked at 750°C for 30 minutes (the pouring temperature of aluminum alloys). The baked coating sample is taken out and left to cool naturally at room temperature. The test column is directly bonded to the surface of the coating with an adhesive. After the adhesive is cured, the bonded test combination is placed on a suitable tensile testing machine. The bonded test combination is subjected to a controllable tensile test to measure the tensile force required to destroy the adhesion between the coating and the substrate, and the tensile force is used to indicate the adhesion.

[0061] During the above test, the paint dry film thickness can be controlled at 1 mm.

[0062] The test results of the above embodiments and comparative examples of the present application are shown in the following table.

[0063]

[0064] The test results of the above examples and comparative examples show that the active magnesium oxide, silica sol and bentonite play a synergistic role with the assistance of cellulose, thereby improving the fire resistance, crack resistance and adhesion of the coating. Comparing Examples 1 to 3 with Examples 4 to 9, it can be seen that limiting the proportion of specific components is beneficial to further improving the fire resistance, crack resistance and adhesion of the coating.

[0065] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A 3D printing photosensitive resin mold investment casting coating for aluminum alloy, characterized in that: By weight, it comprises 7-10 parts of active magnesium oxide, 16-20 parts of silica sol, wherein the solid content of the silica sol is 20%-32%, 12-18 parts of bentonite, 2-6 parts of cellulose and 16-30 parts of epoxy resin.

2. The coating according to claim 1, characterized in that By weight, the ratio of silicon dioxide in the silica sol: the active magnesium oxide: the bentonite is 1:1.2-1.5:2.5-2.

6.

3. The coating according to claim 2, characterized in that By weight, the epoxy resin: the cellulose is 3-7:

1.

4. The coating according to claim 3, characterized in that The amount of the silica sol is 17-18 parts.

5. The coating according to claim 4, characterized in that The amount of bentonite is 12-16 parts.

6. The coating according to claim 5, characterized in that The epoxy resin is present in an amount of 18 to 25 parts.

7. The coating according to claim 1, characterized in that The epoxy resin is selected from one of glycidyl ether epoxy resin, glycidyl ester epoxy resin or glycidyl amine epoxy resin.

8. The coating according to claim 1, characterized in that The coating further comprises 1-2 parts of an auxiliary agent by weight, and the auxiliary agent comprises a defoaming agent.

9. A method for preparing an aluminum alloy 3D printing photosensitive resin mold investment casting coating, characterized in that: The preparation method uses the coating component according to any one of claims 1 to 8, and the preparation method comprises the following steps: Mixing active magnesium oxide into silica sol according to a set ratio to obtain a first mixture; mixing bentonite and cellulose into epoxy resin in a set ratio to obtain a second mixture; The first mixture is mixed into the second mixture to obtain a coating.

10. The preparation method according to claim 9, characterized in that The mixing temperature of the first mixture is 20-40°C and the mixing speed is 1500-2000 rpm, the mixing temperature of the second mixture is 20-40°C and the mixing speed is 1000-3000 rpm, and the mixing temperature of the coating is 20-40°C and the mixing speed is 2000-3000 rpm.

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