Preparation method and application of modified investment casting wax

Abstract

The invention discloses a preparation method and application of modified investment casting wax. The modified casting wax is prepared from the following raw materials and components in parts by mass: 10 to 25 parts of paraffin, 5 to 10 parts of lignite wax, 10 to 20 parts of C5 petroleum resin, 0 to 5 parts of beewax, 2 to 6 parts of polyethylene wax, 0 to 5 parts of stearic acid, 1 to 3 parts of ethylene-vinyl acetate copolymer, 5 to 10 parts of C9 petroleum resin, 5 to 10 parts of hydrogenated C9 petroleum resin, 5 to 10 parts of hydrogenated terpene resin, 5 to 10 parts of D-mannitol, 0 to 5 parts of polymethyl methacrylate, 5 to 15 parts of adipic acid and 1 to 5 parts of hydrogenated rosin glyceride. 5-10 parts of microcrystalline wax, 0-2 parts of starch, 0-4 parts of carnauba wax and 0-4 parts of candelilla wax. The modified casting wax material has good comprehensive performance, the surface of the wax material is flat and smooth, demolding is easy, the low linear shrinkage rate is achieved, and the modified casting wax material is especially suitable for precise casting of thick, large and complex castings.

Description

Technical Field

[0001] The present invention belongs to the technical field of investment casting wax materials, and specifically relates to a preparation method and application of a modified investment casting wax.

Background Art

[0002] Precision casting is an advanced material forming process. Its castings are precise, complex, and close to the final shape of the part, and can be used directly without machining or with very little machining. In the precision casting process, the dimensional accuracy of the wax pattern directly determines and affects the dimensional accuracy of the final product. Traditional wax has been used as a general pattern material for the investment casting process. With the increasing demand for precise dimensions and complex shapes, various materials have been mixed with wax to develop patterns more suitable for investment casting to overcome the performance limitations exhibited by traditional wax.

[0003] For precision castings, the most important performance index is dimensional accuracy, which requires the shrinkage rate of the precision casting wax to be as low as possible. See the Chinese patent document with the patent document number CN110205092A, which proposes a preparation method of a repair wax for investment casting; the Chinese patent document with the patent document number CN108329701A gives a preparation method of an investment casting wax; the Chinese patent document with the patent document number CN109265847A proposes a preparation method of a quick-drying composite wax for investment casting. These patent documents mainly solve process problems such as demouldability, surface finish of the product, and molding speed, and involve less in the strength performance, dimensional stability, and operability of investment casting wax.

Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a preparation method and application of a modified investment casting wax.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: A preparation method of a modified investment casting wax, the preparation method comprising the following steps: (1) adding paraffin wax, beeswax, candelilla wax, microcrystalline wax, carnauba wax and montan wax into a polymerization bottle, heating and stirring at 80-100 °C for 30-45 min until completely melted; (2) continuously heating at 90-100 °C, adding polyethylene wax and stearic acid to melt, and continuously stirring for 10-20 min until completely melted; (3) continuing to heat up to 110-120 °C, adding ethylene-vinyl acetate copolymer, and keeping warm for 1-1.5 h until the ethylene-vinyl acetate copolymer is completely melted; (4) adding C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin, hydrogenated rosin glyceride to the above materials, keeping warm at 120 °C for 1-1.5 h, and slowly stirring until completely melted into a transparent state; (5) cooling to 90-100 °C, adding D-mannitol, starch, adipic acid, polymethyl methacrylate in sequence, keeping warm for 30-60 min, and making into granules after cooling to obtain precision casting wax; in the above preparation method, the mass ratio of each component is: paraffin wax 10-25 parts, montan wax 5-10 parts, C5 petroleum resin 10-20 parts, beeswax 0-5 parts, polyethylene wax 2-6 parts, stearic acid 0-5 parts, ethylene-vinyl acetate copolymer 1-3 parts, C9 petroleum resin 5-10 parts, hydrogenated C9 petroleum resin 5-10 parts, hydrogenated terpene resin 5-10 parts, D-mannitol 5-10 parts, polymethyl methacrylate 0-5 parts, adipic acid 5-15 parts, hydrogenated rosin glyceride 1-5 parts, microcrystalline wax 5-10 parts, starch 0-2 parts, carnauba wax 0-4 parts, candelilla wax 0-4 parts.

[0006] Furthermore, in the above investment casting wax preparation method, the melting point of the paraffin wax is 60-62 °C, which is 60# fully refined paraffin wax; the montan wax has a melting point of 75-86 °C; the melting point of the microcrystalline wax is 75 °C; the melting point of the beeswax is 62-67 °C, and the softening point of the candelilla wax is 67-71 °C.

[0007] Furthermore, in the above investment casting wax preparation method, the melting point of the polyethylene wax is 90-100 °C, and the average relative molecular mass is 1500-2000.

[0008] Furthermore, in the above investment casting wax preparation method, the content of vinyl acetate copolymer in the ethylene-vinyl acetate copolymer is 28 wt%, and the melt index is 400 g / 10 min.

[0009] Furthermore, in the above method for preparing investment casting wax, the melting point of the stearic acid is 67-72°C; the melting point of the C5 petroleum resin is 80-100°C; the melting point of the C9 petroleum resin is 100-120°C; the melting point of the hydrogenated C9 petroleum resin is 100-130°C; the melting point of the hydrogenated terpene resin is 80-90°C.

[0010] Furthermore, in the above method for preparing investment casting wax, the softening point of the hydrogenated rosin glyceride is 78-90°C, and the acid value is ≤9 ((KOH) / (mg / g)).

[0011] Furthermore, in the above method for preparing investment casting wax, 100% of the D-mannitol and adipic acid can pass through a 100-mesh sieve, and 80% can pass through a 200-mesh sieve; for the starch, 80% can pass through a 100-mesh sieve, and 50% can pass through a 200-mesh sieve.

[0012] The application of a modified investment casting wax in the present invention adopts the following technical solution: The modified investment casting wax is prepared by the above method for preparing a modified investment casting wax, and this investment casting wax is applied to prepare a wax model for high-precision aviation casting structural parts.

[0013] The inventor of the present invention designed and studied the resin-modified wax based on the composite formula and preparation process of precision casting wax, introduced the influence of wax materials such as montan wax, ethylene-vinyl acetate, adipic acid, and mannitol and other functional additives on the surface hardness, viscosity, shrinkage rate, bending strength, melting point and other properties of the modified precision casting wax, adjusted the composition of the wax mold material and its proportion, and finally achieved the high bending hardness and surface hardness of the precision casting wax-modified precision casting wax, and the purpose of reducing the shrinkage rate of the precision casting wax-modified precision casting wax. The investment casting wax prepared by the present invention can reach the level of high-standard products of the same type abroad.

Specific Embodiments

[0014] The present invention is a method for preparing investment casting wax and the specific application of the investment casting wax prepared by this preparation method.

[0015] When preparing the investment casting wax of the present invention, prepare raw materials according to the following mass component ratio:

[0016] (1) 10-25 parts of paraffin wax;

[0017] (2) 5-10 parts of montan wax;

[0018] (3) 10-20 parts of C5 petroleum resin;

[0019] (4) 0-5 parts of beeswax (when the value is 0, it means not adding);

[0020] (5) 2-6 parts of polyethylene wax;

[0021] (6) 0 - 5 parts of stearic acid (when the value is 0, it means not added);

[0022] (7) 1 - 3 parts of ethylene - vinyl acetate copolymer;

[0023] (8) 5 - 10 parts of C9 petroleum resin;

[0024] (9) 5 - 10 parts of hydrogenated C9 petroleum resin;

[0025] (10) 5 - 10 parts of hydrogenated terpene resin;

[0026] (11) 5 - 10 parts of D - mannitol;

[0027] (12) 0 - 5 parts of polymethyl methacrylate (when the value is 0, it means not added);

[0028] (13) 5 - 15 parts of adipic acid;

[0029] (14) 1 - 5 parts of hydrogenated rosin glyceride;

[0030] (15) 5 - 10 parts of microcrystalline wax;

[0031] (16) 0 - 2 parts of starch (when the value is 0, it means not added);

[0032] (17) 0 - 4 parts of carnauba wax (when the value is 0, it means not added);

[0033] (18) 0 - 4 parts of candelilla wax (when the value is 0, it means not added).

[0034] The total of the above components is 100 parts.

[0035] The melting point of the paraffin wax is 60 - 62°C, and it is 60# fully refined paraffin wax; the montan wax has a melting point of 75 - 86°C; the microcrystalline wax has a melting point of 75°C; the beeswax has a melting point of 62 - 67°C; the polyethylene wax has a melting point of 90 - 100°C and an average relative molecular mass of 1500 - 2000; the candelilla wax has a softening point of 67 - 71°C; the ethylene-vinyl acetate copolymer contains 28 wt% vinyl acetate and has a melt flow rate of 400 g / 10 min; the stearic acid has a melting point of 67 - 72°C; the C5 petroleum resin has a melting point of 80 - 100°C; the C9 petroleum resin has a melting point of 100 - 120°C; the hydrogenated C9 petroleum resin has a melting point of 100 - 130°C; the hydrogenated terpene resin has a melting point of 80 - 90°C; the hydrogenated rosin glyceride has a softening point of 78 - 90°C and an acid value of ≤9 ((KOH) / (mg / g)); 100% of the D-mannitol and adipic acid can pass through a 100-mesh sieve, and 80% can pass through a 200-mesh sieve; for the starch, 80% can pass through a 100-mesh sieve, and 50% can pass through a 200-mesh sieve.

[0036] The preparation method of a modified precision casting wax pattern of the present invention is carried out according to the following steps:

[0037] (1) First, add paraffin wax, beeswax, candelilla wax, microcrystalline wax, carnauba wax and montan wax into a polymerization flask, heat up to 80 - 100°C and stir for 30 - 45 min until completely melted;

[0038] (2) Continue to heat at 90 - 100°C, add polyethylene wax and stearic acid to melt, and continuously stir for 10 - 20 min until completely melted;

[0039] (3) Continue to heat up to 110 - 120°C, add ethylene-vinyl acetate copolymer, and keep warm for 1 - 1.5 h until the ethylene-vinyl acetate copolymer is completely melted;

[0040] (4) Add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin, and hydrogenated rosin glyceride to the above materials, keep warm at 120°C for 1 - 1.5 h, and slowly stir until completely melted into a transparent state;

[0041] (5) Cool down to 90 - 100°C, add D-mannitol, starch, adipic acid, and polymethyl methacrylate in sequence, keep warm for 30 - 60 min, and make into granules after cooling to obtain the precision casting wax.

[0042] The obtained precision casting wax can be melted and injected by any injection machine to manufacture various types of small mold parts, and various properties of the small mold parts can be tested.

[0043] The test method for the precision casting mold material is as follows:

[0044] Melting point: The melting point of the precision investment casting wax is tested by DSC;

[0045] Hardness: The hardness of the precision investment casting wax is tested by a Shore hardness tester;

[0046] Viscosity: It is carried out according to the method specified in GB / T14235.1;

[0047] Flexural strength: It is carried out according to the method specified in GB / T14235.1;

[0048] Linear shrinkage rate: It is carried out according to the method specified in GB / T14235.1;

[0049] Ash content: The residual ash of the precision investment casting wax is tested by TG.

[0050] The modified precision investment casting wax prepared by the present invention has the following performance characteristics: the viscosity is 249-680 mPa·s, the shrinkage rate is 0.3%-0.7%, ensuring the stability during the casting process; the flexural strength is 6-8 MPa, and the hardness is between 49 and 56, endowing the wax with high strength and high hardness, thereby improving the precision of the casting; the ash content is less than 0.02%, ensuring no pollution during the casting process; the melting point is between 53 and 59 °C, which ensures that the melting point of the modified precision investment casting wax is between 54 and 58 °C, making it easier to demold during the casting process. The stability, high strength, high hardness, low ash content, suitable melting point, and easy demolding of the modified precision investment casting wax are beneficial to improving the efficiency of investment precision casting. The internal components of the modified precision investment casting wax provided by the present invention are uniform, the shrinkage rates of each part are uniform, and the wax has relatively high strength, and can be widely used in the preparation of wax models for high-precision aviation casting structural parts and other wax models for precision casting.

[0051] The following will further elaborate on the investment casting wax of the present invention in conjunction with the embodiments of the present invention:

[0052] Example 1

[0053] The raw materials and mass component ratios of this investment casting wax are: 26 parts of paraffin wax, 20 parts of montan wax, 7 parts of polyethylene wax, 2 parts of ethylene-vinyl acetate copolymer, 3 parts of stearic acid, 35 parts of C5 petroleum resin, 12 parts of C9 petroleum resin, 10 parts of hydrogenated terpene resin, 15 parts of microcrystalline wax, 10 parts of adipic acid, 15 parts of hydrogenated C9 petroleum resin, 10 parts of hydrogenated rosin glyceride, 3 parts of candelilla wax, 6 parts of carnauba wax, 20 parts of D-mannitol, 5 parts of polymethyl methacrylate, and 1 part of starch. The above components total 200 parts.

[0054] Its preparation method includes the following steps:

[0055] (1) First, add paraffin wax, beeswax, candelilla wax, microcrystalline wax, carnauba wax and montan wax into the polymerization bottle, heat it up to 80 °C and stir for 30 min until completely melted;

[0056] (2) Continue to heat at 100 °C, add polyethylene wax and stearic acid to melt, and continuously stir for 10 min until completely melted;

[0057] (3) Continue to heat up to 115 °C, add ethylene-vinyl acetate copolymer, keep warm for 1.5 h until the ethylene-vinyl acetate copolymer is completely melted, and stir slowly to prevent ball formation;

[0058] (4) Continue to heat the material to 120 °C, add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin and hydrogenated rosin glyceride, keep warm for 1.5 h, stir slowly, and wait until it is completely melted into a transparent state;

[0059] (5) Finally, cool down to 90 °C, add D-mannitol, adipic acid, polymethyl methacrylate and starch in sequence, keep warm for 60 min, and make granules after cooling to obtain precision casting wax.

[0060] Example 2:

[0061] The raw materials and mass component ratios of Example 2 are as follows: 30 parts of paraffin wax, 15 parts of montan wax, 5 parts of polyethylene wax, 5 parts of beeswax, 2 parts of ethylene-vinyl acetate copolymer, 30 parts of C5 petroleum resin, 12 parts of C9 petroleum resin, 13 parts of hydrogenated C9 petroleum resin, 15 parts of hydrogenated terpene resin, 15 parts of microcrystalline wax, 10 parts of D-mannitol, 25 parts of adipic acid, 10 parts of hydrogenated rosin glyceride, 6 parts of carnauba wax, 5 parts of polymethyl methacrylate, and 2 parts of starch. The total of the above components is 200 parts.

[0062] Its preparation method includes the following steps:

[0063] (1) First, add paraffin wax, beeswax, microcrystalline wax, carnauba wax and montan wax into the polymerization bottle, heat it up to 80 °C and stir for 30 min until completely melted;

[0064] (2) Continue to heat at 100 °C, add polyethylene wax to melt, and continuously stir for 10 min until completely melted;

[0065] (3) Continue to heat up to 115 °C, add ethylene-vinyl acetate copolymer, keep warm for 1.0 h until the ethylene-vinyl acetate copolymer is completely melted, and stir slowly to prevent ball formation;

[0066] (4) Continuously heat the material to 120°C, add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin and hydrogenated rosin glyceride, keep the temperature for 1.25 h, stir slowly, and wait until it is completely melted into a transparent state;

[0067] (5) Finally, cool down to 90°C, add D-mannitol, adipic acid, polymethyl methacrylate and starch in sequence, keep the temperature for 60 min, and make granules after cooling to obtain precision casting wax.

[0068] Example 3:

[0069] The raw materials and mass component ratios of Example 3 are as follows: 28 parts of paraffin wax, 15 parts of lignite wax, 5 parts of polyethylene wax, 2 parts of ethylene-vinyl acetate copolymer, 3 parts of stearic acid, 22 parts of C5 petroleum resin, 15 parts of C9 petroleum resin, 15 parts of hydrogenated C9 petroleum resin, 10 parts of hydrogenated terpene resin, 20 parts of microcrystalline wax, 15 parts of D-mannitol, 25 parts of adipic acid, 10 parts of hydrogenated rosin glyceride, 3 parts of candelilla wax, 6 parts of carnauba wax, 5 parts of polymethyl methacrylate, and 1 part of starch. The total of the above components is 200 parts.

[0070] (1) First, add paraffin wax, candelilla wax, carnauba wax, microcrystalline wax and lignite wax into the polymerization flask, heat up to 90°C, and stir for 30 min until completely melted;

[0071] (2) Continue to heat at 100°C, add polyethylene wax and stearic acid to melt, and continuously stir for 20 min until completely melted;

[0072] (3) Continue to heat up to 115°C, add ethylene-vinyl acetate copolymer, keep the temperature for 1.2 h until the ethylene-vinyl acetate copolymer is completely melted, and stir slowly to prevent ball formation;

[0073] (4) Continuously heat the material to 120°C, add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin and hydrogenated rosin glyceride, keep the temperature for 1.2 h, stir slowly, and wait until it is completely melted into a transparent state;

[0074] (5) Finally, cool down to 90°C, add D-mannitol, adipic acid, polymethyl methacrylate and starch in sequence, keep the temperature for 60 min, and make granules after cooling to obtain precision casting wax.

[0075] Example 4:

[0076] The raw materials and mass component ratios of Example 4 are as follows: 35 parts of paraffin wax, 16 parts of montan wax, 5 parts of polyethylene wax, 8 parts of beeswax, 4 parts of ethylene-vinyl acetate copolymer, 5 parts of stearic acid, 35 parts of C5 petroleum resin, 15 parts of C9 petroleum resin, 10 parts of hydrogenated C9 petroleum resin, 10 parts of hydrogenated terpene resin, 20 parts of microcrystalline wax, 10 parts of D-mannitol, 15 parts of adipic acid, 5 parts of hydrogenated rosin glyceride, and 7 parts of polymethyl methacrylate. The total of the above components is 200 parts.

[0077] Its preparation method comprises the following steps:

[0078] (1) First, add paraffin wax, beeswax, microcrystalline wax, and montan wax into a polymerization flask, heat it up to 90 °C, and stir for 30 min until completely melted;

[0079] (2) Continue to heat at 100 °C, add polyethylene wax and stearic acid to melt, and continuously stir for 20 min until completely melted;

[0080] (3) Continue to heat up to 115 °C, add ethylene-vinyl acetate copolymer, keep warm for 1.0 h until the ethylene-vinyl acetate copolymer is completely melted, and slowly stir to prevent ball formation;

[0081] (4) Continue to heat the material to 120 °C, add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin, and hydrogenated rosin glyceride, keep warm for 1.5 h, slowly stir, and wait until completely melted into a transparent state;

[0082] (5) Finally, cool down to 90 °C, add D-mannitol, adipic acid, and polymethyl methacrylate in sequence, keep warm for 45 min, and make it into granules after cooling to obtain precision casting wax.

[0083] Example 5:

[0084] The raw materials and mass component ratios of Example 5 are as follows: 30 parts of paraffin wax, 14 parts of montan wax, 4 parts of polyethylene wax, 4 parts of ethylene-vinyl acetate copolymer, 4 parts of stearic acid, 20 parts of C5 petroleum resin, 16 parts of C9 petroleum resin, 16 parts of hydrogenated C9 petroleum resin, 10 parts of hydrogenated terpene resin, 18 parts of microcrystalline wax, 12 parts of D-mannitol, 25 parts of adipic acid, 8 parts of hydrogenated rosin glyceride, 6 parts of candelilla wax, 6 parts of carnauba wax, 4 parts of polymethyl methacrylate, and 3 parts of starch. The total of the above components is 200 parts.

[0085] Its preparation method comprises the following steps:

[0086] (1) First, add paraffin wax, candelilla wax, carnauba wax, microcrystalline wax, and montan wax into a polymerization flask, heat it up to 85 °C, and stir for 30 min until completely melted;

[0087] (2) Continuously heat at 100 °C, add polyethylene wax and stearic acid and melt them, and continuously stir for 20 min until completely melted;

[0088] (3) Continue to heat up to 115 °C, add ethylene-vinyl acetate copolymer, keep warm for 1.5 h until the ethylene-vinyl acetate copolymer is completely melted, and slowly stir to prevent ball formation;

[0089] (4) Continue to heat the material to 120 °C, add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin and hydrogenated rosin glyceride, keep warm for 1.2 h, slowly stir, and wait until completely melted into a transparent state;

[0090] (5) Finally, cool down to 90 °C, add D-mannitol, adipic acid, polymethyl methacrylate and starch in sequence, keep warm for 60 min, and make into granules after cooling to obtain precision casting wax.

[0091] Example VI:

[0092] The raw materials and mass component ratios of Example VI are: 40 parts of paraffin wax, 15 parts of lignite wax, 5 parts of carnauba wax, 5 parts of polyethylene wax, 2 parts of ethylene-vinyl acetate copolymer, 2 parts of stearic acid, 30 parts of C5 petroleum resin, 12 parts of C9 petroleum resin, 20 parts of hydrogenated C9 petroleum resin, 10 parts of hydrogenated terpene resin, 10 parts of microcrystalline wax, 12 parts of D-mannitol, 29 parts of adipic acid, 5 parts of hydrogenated rosin glyceride, and 3 parts of starch. The above components total 200 parts.

[0093] Its preparation method includes the following steps:

[0094] (1) First, add paraffin wax, microcrystalline wax, carnauba wax and lignite wax into the polymerization flask, heat up to 80 °C and stir for 30 min until completely melted;

[0095] (2) Continuously heat at 100 °C, add polyethylene wax and stearic acid and melt them, and continuously stir for 10 min until completely melted;

[0096] (3) Continue to heat up to 115 °C, add ethylene-vinyl acetate copolymer, keep warm for 1.2 h until the ethylene-vinyl acetate copolymer is completely melted, and slowly stir to prevent ball formation;

[0097] (4) Continue to heat the material to 120 °C, add C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin and hydrogenated rosin glyceride, keep warm for 1.25 h, slowly stir, and wait until completely melted into a transparent state;

[0098] (5) Finally, cool down to 90 °C, add D-mannitol, adipic acid and starch in sequence, keep warm for 60 min, and make into granules after cooling to obtain precision casting wax.

[0099] Comparative Example 1:

[0100] The raw materials and mass component ratios of Comparative Example 1 are as follows: 30 parts of paraffin wax, 20 parts of montan wax, 10 parts of polyethylene wax, 4 parts of beeswax, 5 parts of carnauba wax, 2 parts of ethylene-vinyl acetate copolymer, 3 parts of stearic acid, 30 parts of C5 petroleum resin, 10 parts of C9 petroleum resin, 10 parts of hydrogenated C9 petroleum resin, 15 parts of hydrogenated terpene resin, 25 parts of microcrystalline wax, 5 parts of adipic acid, 20 parts of D-mannitol, 5 parts of hydrogenated rosin glyceride, 5 parts of polymethyl methacrylate, and 1 part of starch. Among the above components, the amounts of microcrystalline wax and adipic acid exceed the dosage ranges of the present invention.

[0101] The preparation method is the same as that of Example 1.

[0102] Comparative Example 2:

[0103] The raw materials and mass component ratios of Comparative Example 2 are as follows: 30 parts of paraffin wax, 25 parts of montan wax, 5 parts of polyethylene wax, 5 parts of beeswax, 3 parts of ethylene-vinyl acetate copolymer, 5 parts of stearic acid, 21 parts of C5 petroleum resin, 12 parts of C9 petroleum resin, 12 parts of hydrogenated C9 petroleum resin, 15 parts of hydrogenated terpene resin, 16 parts of microcrystalline wax, 15 parts of adipic acid, 10 parts of D-mannitol, 15 parts of hydrogenated rosin glyceride, 8 parts of carnauba wax, and 3 parts of polymethyl methacrylate.

[0104] Among the above components, the amounts of montan wax and hydrogenated rosin glyceride exceed the dosage ranges of the present invention.

[0105] The preparation method is the same as that of Example 1.

[0106] Comparative Example 3:

[0107] The raw materials and mass component ratios of Comparative Example 3 are as follows: 25 parts of paraffin wax, 15 parts of montan wax, 4 parts of candelilla wax, 4 parts of carnauba wax, 8 parts of polyethylene wax, 3 parts of ethylene-vinyl acetate copolymer, 3 parts of stearic acid, 30 parts of C5 petroleum resin, 15 parts of C9 petroleum resin, 15 parts of hydrogenated C9 petroleum resin, 15 parts of hydrogenated terpene resin, 15 parts of microcrystalline wax, 25 parts of adipic acid, 5 parts of D-mannitol, 10 parts of hydrogenated rosin glyceride, 3 parts of polymethyl methacrylate, and 5 parts of starch.

[0108] Among the above components, the amounts of D-mannitol and starch exceed the dosage ranges of the present invention.

[0109] The preparation method is the same as that of Example 1.

[0110] Comparative Example 4:

[0111] The raw materials and mass component ratios of Comparative Example 4 are as follows: 33 parts of paraffin wax, 10 parts of montan wax, 6 parts of polyethylene wax, 5 parts of beeswax, 2 parts of ethylene-vinyl acetate copolymer, 13 parts of stearic acid, 33 parts of C5 petroleum resin, 15 parts of C9 petroleum resin, 15 parts of hydrogenated C9 petroleum resin, 15 parts of hydrogenated terpene resin, 15 parts of microcrystalline wax, 10 parts of adipic acid, 14 parts of D-mannitol, 4 parts of hydrogenated rosin glyceride, 5 parts of carnauba wax, 4 parts of polymethyl methacrylate, and 1 part of starch.

[0112] Among the above components, the amount of stearic acid exceeds the dosage range of the present invention.

[0113] The preparation method is the same as that of Example 1.

[0114] The investment casting waxes prepared in the above Examples 1-6 and Comparative Examples 1-4 were used to make small mold parts through an injection machine, and the side heads were carried out. The test performances are shown in Table 1 below.

[0115] Table 1: Performance test data of investment casting wax patterns

[0116]

[0117] As can be seen from Table 1, the investment casting wax of the present invention has a moderate melting point, a small linear shrinkage rate, high hardness, high bending strength, small ash content, and good viscosity controllability. At the same time, it can also be seen from Table 1 that when certain components in the investment casting wax pattern formula exceed the range, it has a great impact on the comprehensive performance, especially the shrinkage rate of the precision casting wax obtained will increase significantly.

[0118] The above are the better technical solutions of the embodiments of the present invention. The above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Those of ordinary skill in the art can still modify or equivalently replace the technical solutions of the embodiments of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the scope of the technical plan of the embodiments of the present invention.

Claims

1. A method for preparing a modified investment casting wax, characterized in that: The preparation method comprises the following steps: (1) Add paraffin, beeswax, candelilla wax, microcrystalline wax, carnauba wax and lignite wax into a polymerization bottle, heat and stir at 80-100° C. for 30-45 minutes until completely melted; (2) Continue heating at 90-100°C, add polyethylene wax and stearic acid to melt, and stir continuously for 10-20 minutes until completely melted; (3) Continue heating to 110-120° C., add ethylene-vinyl acetate copolymer, and keep the temperature for 1-1.5 hours until the ethylene-vinyl acetate copolymer is completely melted; (4) Add one or more of C5 petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, hydrogenated terpene resin, and hydrogenated rosin glycerol ester to the above materials, keep the temperature at 120° C. for 1 to 1.5 hours, and slowly stir until the mixture is completely melted and becomes transparent; (5) cooling to 90-100° C., adding one or more of D-mannitol, starch, adipic acid, and polymethyl methacrylate in sequence, keeping the temperature for 30-60 min, and cooling to form granules to obtain precision casting wax; In the above preparation method, the mass ratio of each component is: 10-25 parts of paraffin wax, 5-10 parts of montan wax, 10-20 parts of C5 petroleum resin, 0-5 parts of beeswax, 2-6 parts of polyethylene wax, 0-5 parts of stearic acid, 1-3 parts of ethylene-vinyl acetate copolymer, 5-10 parts of C9 petroleum resin, 5-10 parts of hydrogenated C9 petroleum resin, 5-10 parts of hydrogenated terpene resin, 5-10 parts of D-mannitol, 0-5 parts of polymethyl methacrylate, 5-15 parts of adipic acid, 1-5 parts of hydrogenated rosin glycerol ester, 5-10 parts of microcrystalline wax, 0-2 parts of starch, 0-4 parts of carnauba wax, and 0-4 parts of candelilla wax.

2. The method for preparing a modified investment casting wax according to claim 1, characterized in that: The melting point of the paraffin wax is 60-62°C, which is 60# fully refined paraffin wax; the melting point of the lignite wax is 75-86°C; the melting point of the microcrystalline wax is 75°C; the melting point of the beeswax is 62-67°C, and the softening point of the candelilla wax is 67-71°C.

3. The method for preparing a modified investment casting wax according to claim 1, characterized in that: The polyethylene wax has a melting point of 90-100° C. and an average relative molecular mass of 1500-2000.

4. The method for preparing a modified investment casting wax according to claim 1, characterized in that: The vinyl acetate copolymer content in the ethylene-vinyl acetate copolymer is 28 wt % and the melt index is 400 g / 10 min.

5. The method for preparing a modified investment casting wax according to claim 1, characterized in that: The melting point of the stearic acid is 67-72°C; the melting point of the C5 petroleum resin is 80-100°C; the melting point of the C9 petroleum resin is 100-120°C; the melting point of the hydrogenated C9 petroleum resin is 100-130°C; and the melting point of the hydrogenated terpene resin is 80-90°C.

6. The method for preparing a modified investment casting wax according to claim 1, characterized in that: The softening point of the hydrogenated rosin glycerol ester is 78-90° C., and the acid value is ≤9 ((KOH) / (mg / g)).

7. The method for preparing a modified investment casting wax according to claim 1, characterized in that: 100% of the D-mannitol and adipic acid can pass through a 100-mesh sieve, and 80% can pass through a 200-mesh sieve; 80% of the starch can pass through a 100-mesh sieve, and 50% can pass through a 200-mesh sieve.

8. An application of a modified investment casting wax, characterized in that: The modified investment casting wax is prepared by the preparation method of a modified investment casting wax described in any one of claims 1 to 7, and the modified investment casting wax is used for preparing wax models of high-precision aviation casting structural parts.

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