Release agent for centrifugal elbow casting and preparation method thereof

Abstract

The invention discloses a release agent for centrifugal elbow casting and a preparation method thereof, and relates to the technical field of release agents for casting, the preparation method comprises the following steps: S1, adding modified silicone oil and white oil into a reaction kettle, and heating and stirring at 60-70 DEG C to obtain base oil; s2, adding a wetting agent and an emulsifying agent into deionized water, uniformly stirring, heating to 30-40 DEG C, then adding an anti-rust agent and a defoaming agent, and continuously uniformly stirring to obtain a prefabricated emulsion; and S3, adding the prefabricated emulsion into the base oil, and uniformly stirring to obtain the release agent for centrifugal elbow casting.

Description

Technical Field

[0001] The present invention relates to the technical field of mold release agents for casting, and specifically to a mold release agent for centrifugal bent pipe casting and a preparation method thereof. Background Art

[0002] Centrifugally cast bent pipes are steel pipes produced by using the centrifugal casting process. In this process, molten metal is poured into a preheated rotating mold, and the centrifugal force is used to evenly deposit the metal liquid on the inner wall of the mold. After solidification and treatment, the required steel pipe products are formed. The steel pipes prepared by this process do not require an inner core, the thickness is easy to control, and the production efficiency is high.

[0003] However, after casting steel pipes using the centrifugal casting process, problems such as deformation and wear of the mold after long-term use, and uneven surfaces of the produced steel pipes often occur. In the prior art, mold release agents are generally used to improve the service life of the mold, but their main component is paraffin. During use, preheating is required, the thickness of the mold release agent is inconvenient to control, and the mold release agents in the prior art generally do not improve the heat conduction effect, which may cause local overheating, resulting in an increase in the thermal stress of the produced steel pipes and a decline in product quality control.

[0004] In summary, to solve the above problems, it is of great significance to prepare a mold release agent for centrifugal bent pipe casting that can improve the smoothness of steel pipes and is convenient to use. Summary of the Invention

[0005] The purpose of the present invention is to provide a mold release agent for centrifugal bent pipe casting and a preparation method thereof to solve the problems raised in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A mold release agent for centrifugal bent pipe casting, comprising the following raw materials, calculated by 100 parts by mass: 35 - 50 parts of modified silicone oil, 20 - 30 parts of deionized water, 2 - 3 parts of modified graphene oxide, 2.5 - 5 parts of emulsifier, 1 - 2 parts of wetting agent, 0.5 - 1 part of rust inhibitor, 0.1 - 0.5 part of defoamer, and the balance is white oil.

[0008] More preferably, the modified silicone oil comprises the following substances, calculated by mass: 20 - 30 parts of silicone oil, 15 - 20 parts of modified hydrogen-containing silicone oil.

[0009] More preferably, the emulsifier comprises the following substances, calculated by mass: 1 - 2 parts of polyglycerol fatty acid ester, 1 - 2 parts of polyoxyethylene fatty alcohol ether, 0.5 - 1 part of Span 80.

[0010] More preferably, the wetting agent comprises the following substances by mass: 0.5 to 0.8 parts of isopropanol, 0.4 to 0.9 parts of propylene glycol, and 0.1 to 0.3 parts of lauryl alcohol polyoxyethylene ether.

[0011] More preferably, the rust inhibitor comprises the following substances by mass: 0.25 to 0.5 parts of triethanolamine, 0.25 to 0.5 parts of benzotriazole; the defoaming agent comprises the following substances by mass: 0.05 to 0.2 parts of polydimethylsiloxane, 0.05 to 0.3 parts of tributyl phosphate.

[0012] More preferably, the preparation method of the modified hydrogen-containing silicone oil comprises the following steps:

[0013] (1) Preparation of amino-modified talc powder: Add talc powder to deionized water and disperse it evenly by ultrasonic treatment. Add an amino-silane coupling agent and stir at 45 to 50 °C for 1 to 1.5 h. Filter, wash, and dry to obtain amino-modified talc powder;

[0014] (2) Preparation of alkenyl-modified talc powder: Add amino-modified talc powder and 7-octenoic acid to deionized water and disperse it evenly by ultrasonic treatment. Add an activator and stir at 50 to 60 °C for 3 to 4 h. Filter, wash, and dry to obtain alkenyl-modified talc powder;

[0015] (3) Preparation of modified hydrogen-containing silicone oil: Add alkenyl-modified talc powder to hydrogen-containing silicone oil, stir evenly, add a catalyst, seal, and stir at 70 to 80 °C for 3 to 4 h to obtain modified silicone oil.

[0016] More preferably, the amino-modified talc powder comprises the following raw materials by mass: 8 to 10 parts of talc powder, 2 to 3 parts of amino-silane coupling agent.

[0017] Among them, the particle size of the talc powder is 800 to 1000 mesh.

[0018] More preferably, the alkenyl-modified talc powder comprises the following raw materials by mass: 8 to 10 parts of amino-modified talc powder, 5 to 7 parts of 7-octenoic acid, 2 to 3 parts of activator.

[0019] Among them, the activator includes 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, and their mass ratio is 1:1 to 1.5.

[0020] More preferably, the modified hydrogen-containing silicone oil comprises the following raw materials by mass: 14 to 16 parts of alkenyl-modified talc powder, 10 to 12 parts of hydrogen-containing silicone oil, 0.2 to 0.4 parts of catalyst.

[0021] Among them, the catalyst includes a platinum catalyst.

[0022] More preferably, the preparation method of the modified graphene oxide comprises the following steps:

[0023] (1) Add graphene oxide into deionized water, ultrasonically disperse it evenly, add diaminobutene and an activator, stir at 50-60 °C for 2-3 h, add acrylic acid and an initiator, stir at 60-70 °C for 20-30 min, filter, wash, and dry to obtain modified graphene oxide A;

[0024] (2) Add modified graphene oxide A and 6-aminohexyl dihydrogen phosphate into N,N-dimethylformamide, stir evenly, add an activator, stir at 50-55 °C for 2-3 h, filter, wash, and dry to obtain the modified graphene oxide.

[0025] More preferably, the modified graphene oxide A comprises the following raw materials, by mass: 4-5 parts of graphene oxide, 5-8 parts of diaminobutene, 0.5-1 part of activator, 10-12 parts of acrylic acid, 5-6 parts of initiator.

[0026] Among them, the activator comprises 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, and their mass ratio is 1:1-1.5; the initiator comprises azobisisobutyronitrile.

[0027] More preferably, the modified graphene oxide comprises the following raw materials, by mass: 9-11 parts of modified graphene oxide A, 7-8 parts of 6-aminohexyl dihydrogen phosphate, 2- parts of activator.

[0028] Among them, the activator comprises 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, and their mass ratio is 1:1-1.5.

[0029] More preferably, the preparation method of the release agent for centrifugal elbow casting comprises the following steps:

[0030] S1: Add modified silicone oil and white oil into a reaction kettle, heat and stir at 60-70 °C to obtain base oil;

[0031] S2: Add a wetting agent and an emulsifier into deionized water, stir evenly, heat to 30-40 °C, then add an anti-rust agent and an anti-foaming agent, and continue to stir evenly to obtain a prefabricated emulsion;

[0032] S3: Add the prefabricated emulsion into the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0033] More preferably, the using method of the release agent for centrifugal elbow casting is: preheat the mold to 100-150 °C, during rotation, add an appropriate amount of release agent, and after the release agent is evenly spread in the mold, pour molten steel to start casting.

[0034] Compared with the prior art, the beneficial effects of the present application include the following aspects:

[0035] (1) Talcum powder is added to the mold release agent. Talcum powder is a common industrial product obtained by treating talc, a magnesium silicate mineral of the talc family. It has stable chemical properties and good lubricity. Adding it to the mold release agent can significantly reduce the friction coefficient between the mold and the steel pipe, reduce the resistance during the demolding process, thereby avoiding scratches or deformation on the surface of the steel pipe and improving the appearance quality of the product. By modifying talcum powder and grafting carbon long chains, the dispersibility of talcum powder in the system can be improved, and the lubricity can also be enhanced. To further improve the dispersibility of talcum powder in the mold release agent, it is also grafted with hydrogen-containing silicone oil, which also improves the stability in the system. At the same time, talcum powder can also assist the mold release agent to better adhere to the surface of the mold, reduce the adhesion between the steel pipe and the mold, and improve the demolding effect.

[0036] (2) Graphene oxide is added to the demolding agent. Graphene oxide has excellent thermal stability and can slow down the decomposition of the demolding agent caused by high temperature during the pouring process, thereby improving the high-temperature resistance of the demolding agent. At the same time, graphene oxide also has good thermal conductivity, can reduce the accumulation of heat, reduce damage to the mold, and improve the yield of the prepared steel pipe. By grafting diaminobutene and acrylic acid and initiating copolymerization to form smaller molecular carbon long chains, the dispersibility of graphene oxide in the system is improved, and the demolding effect is enhanced. A phosphate group is also introduced. The phosphate group has excellent chemical activity and hydrophilicity and can form a strong interaction with the surface of the mold, forming a firm and uniform lubricating film on the mold, thereby reducing the adhesion between the steel pipe and the mold and improving the demolding effect.

[0037] (3) The materials used in the mold release agent prepared by the present invention will not corrode the mold and the steel pipe, and the prepared steel pipe has a high yield and good quality. Detailed implementation manners

[0038] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] It should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions and exemplarily include: silicone oil, purity 99%, provided by Hubei Qifei Pharmaceutical Chemical Co., Ltd.; hydrogenated silicone oil, purity 99%, provided by Hubei Yongkuo Technology Co., Ltd.; polyglycerol fatty acid ester, purity 99%, provided by Hebei Zhentian Food Additive Co., Ltd.; polyoxyethylene fatty alcohol ether, purity 99%, provided by Guangzhou Tuoxin Chemical Technology Co., Ltd.; Span 80, purity 99.5%, provided by Hubei Jusheng Technology Co., Ltd.; polydimethylsiloxane, purity 99%, provided by Shanghai Biyang Industrial Co., Ltd.; aminosilane coupling agent, KH-550 (γ-aminopropyltriethoxysilane); graphene oxide, specification 0.2~10μm, provided by Zhejiang Yamei Nano Technology Co., Ltd.; diaminobutene, CAS No.: 18231-61-3; 6-aminohexyl dihydrogen phosphate, purity 99%, provided by Shanghai Haohong Biomedicine Technology Co., Ltd.

[0040] In the following examples, parts are by mass.

[0041] Example 1:

[0042] Step 1: Preparation of modified hydrogenated silicone oil:

[0043] (1) Preparation of amino-modified talc: 9 parts of talc were added to 45 parts of deionized water and ultrasonically dispersed uniformly, 2.5 parts of aminosilane coupling agent were added, and the mixture was stirred at 45°C for 1.5 hours. The mixture was filtered, washed, and dried to obtain amino-modified talc.

[0044] (2) Preparation of olefin-modified talc: 9 parts of amino-modified talc and 6 parts of 7-octenic acid were added to 50 parts of deionized water and ultrasonically dispersed uniformly. 2.5 parts of active agent were added and stirred at 55°C for 3.5 hours. The mixture was filtered, washed, and dried to obtain olefin-modified talc.

[0045] (3) Preparation of modified hydrogenated silicone oil: 15 parts of olefin-modified talc powder was added to 11 parts of hydrogenated silicone oil, stirred evenly, 0.3 parts of catalyst was added, sealed, and stirred at 75°C for 3.5 hours to obtain modified hydrogenated silicone oil;

[0046] Step 2: Preparation of modified graphene oxide:

[0047] (1) 4.5 parts of graphene oxide were added to deionized water and ultrasonically dispersed uniformly, 6.5 parts of diaminobutene and 5.5 parts of activator were added, and stirred at 55°C for 2.5 hours, 11 parts of acrylic acid and 0.5 parts of initiator were added, and stirred at 65°C for 25 minutes, filtered, washed, and dried to obtain modified graphene oxide A;

[0048] (2) Add 10 parts of modified graphene oxide A and 7.5 parts of 6 - aminohexyl dihydrogen phosphate to 45 parts of N,N - dimethylformamide, stir evenly, add 2.5 parts of activator, stir at 50 °C for 2.5 h, filter, wash, and dry to obtain modified graphene oxide;

[0049] Step 3: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0050] S1: Add 42 parts of modified silicone oil (25 parts of silicone oil, 17 parts of modified hydrogen - containing silicone oil) and 27.2 parts of white oil into the reaction kettle, heat and stir at 65 °C to obtain base oil;

[0051] S2: Add 1.4 parts of wetting agent (0.6 part of isopropyl alcohol, 0.6 part of propylene glycol, 0.2 part of lauryl alcohol polyoxyethylene ether), 3.4 parts of emulsifier (1.5 parts of polyglycerol fatty acid ester, 1.2 parts of polyoxyethylene fatty alcohol ether, 0.7 part of Span 80) into 25 parts of deionized water, stir evenly, heat to 35 °C, then add 0.7 part of rust inhibitor (0.35 part of triethanolamine, 0.35 part of benzotriazole), 0.3 part of defoaming agent (0.15 part of polydimethylsiloxane, 0.15 part of tributyl phosphate), and continue to stir evenly to obtain a pre - formed emulsion;

[0052] S3: Add the pre - formed emulsion into the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0053] Example 2:

[0054] Step 1: Preparation of modified hydrogen - containing silicone oil:

[0055] (1) Preparation of amino - modified talc powder: Add 9 parts of talc powder into 45 parts of deionized water, disperse evenly by ultrasonic, add 2.5 parts of amino - silane coupling agent, stir at 45 °C for 1.5 h, filter, wash, and dry to obtain amino - modified talc powder;

[0056] (2) Preparation of alkenyl - modified talc powder: Add 9 parts of amino - modified talc powder and 6 parts of 7 - octenoic acid into 50 parts of deionized water, disperse evenly by ultrasonic, add 2.5 parts of activator, stir at 55 °C for 3.5 h, filter, wash, and dry to obtain alkenyl - modified talc powder;

[0057] (3) Preparation of modified hydrogen - containing silicone oil: Add 15 parts of alkenyl - modified talc powder into 11 parts of hydrogen - containing silicone oil, stir evenly, add 0.3 part of catalyst, seal, and stir at 75 °C for 3.5 h to obtain modified hydrogen - containing silicone oil;

[0058] Step 2: Preparation of modified graphene oxide:

[0059] (1) Add 4.5 parts of graphene oxide to deionized water and disperse it evenly by ultrasonic treatment. Then add 6.5 parts of diaminobutene and 5.5 parts of activator, and stir at 55 °C for 2.5 h. Next, add 11 parts of acrylic acid and 0.5 part of initiator, and stir at 65 °C for 25 min. Filter, wash, and dry to obtain modified graphene oxide A;

[0060] (2) Add 10 parts of modified graphene oxide A and 7.5 parts of 6 - aminohexyl dihydrogen phosphate to 45 parts of N,N - dimethylformamide, stir evenly, add 2.5 parts of activator, and stir at 50 °C for 2.5 h. Filter, wash, and dry to obtain modified graphene oxide;

[0061] Step 3: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0062] S1: Add 35 parts of modified silicone oil (20 parts of silicone oil, 15 parts of modified hydrogen - containing silicone oil) and 40.9 parts of white oil to the reaction kettle, and heat and stir at 60 °C to obtain the base oil;

[0063] S2: Add 1 part of wetting agent (0.5 part of isopropyl alcohol, 0.4 part of propylene glycol, 0.1 part of lauryl alcohol polyoxyethylene ether), 2.5 parts of emulsifier (1 part of polyglycerol fatty acid ester, 1 part of polyoxyethylene fatty alcohol ether, 0.5 part of Span 80) to 20 parts of deionized water, stir evenly, heat to 30 °C, then add 0.5 part of rust inhibitor (0.25 part of triethanolamine, 0.25 part of benzotriazole), 0.1 part of defoamer (0.05 part of polydimethylsiloxane, 0.05 part of tributyl phosphate), and continue to stir evenly to obtain the pre - formed emulsion;

[0064] S3: Add the pre - formed emulsion to the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0065] Example 3

[0066] Step 1: Preparation of modified hydrogen - containing silicone oil:

[0067] (1) Preparation of amino - modified talc powder: Add 9 parts of talc powder to 45 parts of deionized water and disperse it evenly by ultrasonic treatment. Then add 2.5 parts of amino - silane coupling agent, and stir at 45 °C for 1.5 h. Filter, wash, and dry to obtain amino - modified talc powder;

[0068] (2) Preparation of alkenyl - modified talc powder: Add 9 parts of amino - modified talc powder and 6 parts of 7 - octenoic acid to 50 parts of deionized water and disperse it evenly by ultrasonic treatment. Then add 2.5 parts of activator, and stir at 55 °C for 3.5 h. Filter, wash, and dry to obtain alkenyl - modified talc powder;

[0069] (3) Preparation of modified hydrogen-containing silicone oil: Add 15 parts of vinyl-modified talc powder to 11 parts of hydrogen-containing silicone oil, stir evenly, add 0.3 part of catalyst, seal, and stir at 75 °C for 3.5 h to obtain modified hydrogen-containing silicone oil;

[0070] Step 2: Preparation of modified graphene oxide:

[0071] (1) Add 4.5 parts of graphene oxide to deionized water, ultrasonically disperse evenly, add 6.5 parts of diaminobutene and 5.5 parts of activator, stir at 55 °C for 2.5 h, add 11 parts of acrylic acid and 0.5 part of initiator, stir at 65 °C for 25 min, filter, wash, and dry to obtain modified graphene oxide A;

[0072] (2) Add 10 parts of modified graphene oxide A and 7.5 parts of 6-aminohexyl dihydrogen phosphate to 45 parts of N,N-dimethylformamide, stir evenly, add 2.5 parts of activator, stir at 50 °C for 2.5 h, filter, wash, and dry to obtain modified graphene oxide;

[0073] Step 3: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0074] S1: Add 50 parts of modified silicone oil (30 parts of silicone oil, 20 parts of modified hydrogen-containing silicone oil) and 11.5 parts of white oil to the reaction kettle, heat and stir at 70 °C to obtain base oil;

[0075] S2: Add 2 parts of wetting agent (0.8 part of isopropanol, 0.9 part of propylene glycol, 0.3 part of lauryl alcohol polyoxyethylene ether), 5 parts of emulsifier (2 parts of polyglycerol fatty acid ester, 2 parts of polyoxyethylene fatty alcohol ether, 1 part of span 80) to 30 parts of deionized water, stir evenly, heat to 40 °C, then add 1 part of rust inhibitor (0.5 part of triethanolamine, 0.5 part of benzotriazole), 0.5 part of defoamer (0.2 part of polydimethylsiloxane, 0.3 part of tributyl phosphate), and continue to stir evenly to obtain a prefabricated emulsion;

[0076] S3: Add the prefabricated emulsion to the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0077] Comparative Example 1: Based on Example 1, the talc powder is not modified, and the rest of the process remains unchanged.

[0078] Step 1: Preparation of modified hydrogen-containing silicone oil:

[0079] (1) Preparation of modified hydrogen-containing silicone oil: Add 15 parts of talc powder to 11 parts of hydrogen-containing silicone oil, stir evenly, add 0.3 part of catalyst, seal, and stir at 75 °C for 3.5 h to obtain modified hydrogen-containing silicone oil;

[0080] Step 2: Preparation of modified graphene oxide:

[0081] (1) Add 4.5 parts of graphene oxide to deionized water and disperse it evenly by ultrasonic treatment. Then add 6.5 parts of diamino butene and 5.5 parts of activator, stir at 55 °C for 2.5 h, add 11 parts of acrylic acid and 0.5 part of initiator, stir at 65 °C for 25 min, filter, wash, and dry to obtain modified graphene oxide A;

[0082] (2) Add 10 parts of modified graphene oxide A and 7.5 parts of 6 - aminohexyl dihydrogen phosphate to 45 parts of N,N - dimethylformamide, stir evenly, add 2.5 parts of activator, stir at 50 °C for 2.5 h, filter, wash, and dry to obtain modified graphene oxide;

[0083] Step 3: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0084] S1: Add 42 parts of modified silicone oil (25 parts of silicone oil, 17 parts of modified hydrogen - containing silicone oil) and 27.2 parts of white oil to the reaction kettle, heat and stir at 65 °C to obtain base oil;

[0085] S2: Add 1.4 parts of wetting agent (0.6 part of isopropanol, 0.6 part of propylene glycol, 0.2 part of lauryl alcohol polyoxyethylene ether), 3.4 parts of emulsifier (1.5 parts of polyglycerol fatty acid ester, 1.2 parts of polyoxyethylene fatty alcohol ether, 0.7 part of Span 80) to 25 parts of deionized water, stir evenly, heat to 35 °C, then add 0.7 part of rust inhibitor (0.35 part of triethanolamine, 0.35 part of benzotriazole), 0.3 part of defoamer (0.15 part of polydimethylsiloxane, 0.15 part of tributyl phosphate), and continue to stir evenly to obtain a pre - prepared emulsion;

[0086] S3: Add the pre - prepared emulsion to the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0087] Comparative Example 2: Based on Example 1, talcum powder is not grafted with hydrogen - containing silicone oil, and the rest of the process remains unchanged.

[0088] Step 1: Preparation of modified hydrogen - containing silicone oil:

[0089] (1) Preparation of amino - modified talcum powder: Add 9 parts of talcum powder to 45 parts of deionized water and disperse it evenly by ultrasonic treatment. Then add 2.5 parts of amino - silane coupling agent, stir at 45 °C for 1.5 h, filter, wash, and dry to obtain amino - modified talcum powder;

[0090] (2) Preparation of alkenyl - modified talcum powder: Add 9 parts of amino - modified talcum powder and 6 parts of 7 - octenoic acid to 50 parts of deionized water and disperse it evenly by ultrasonic treatment. Then add 2.5 parts of activator, stir at 55 °C for 3.5 h, filter, wash, and dry to obtain alkenyl - modified talcum powder;

[0091] (3) Preparation of modified hydrogen-containing silicone oil: Add 15 parts of vinyl-modified talc powder to 11 parts of hydrogen-containing silicone oil, stir evenly, seal, and stir at 75 °C for 3.5 h to obtain modified hydrogen-containing silicone oil;

[0092] Step 2: Preparation of modified graphene oxide:

[0093] (1) Add 4.5 parts of graphene oxide to deionized water and disperse it evenly by ultrasonic treatment. Add 6.5 parts of diaminobutene and 5.5 parts of activator, stir at 55 °C for 2.5 h, add 11 parts of acrylic acid and 0.5 part of initiator, stir at 65 °C for 25 min, filter, wash, and dry to obtain modified graphene oxide A;

[0094] (2) Add 10 parts of modified graphene oxide A and 7.5 parts of 6-aminohexyl dihydrogen phosphate to 45 parts of N,N-dimethylformamide, stir evenly, add 2.5 parts of activator, stir at 50 °C for 2.5 h, filter, wash, and dry to obtain modified graphene oxide;

[0095] Step 3: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0096] S1: Add 42 parts of modified silicone oil (25 parts of silicone oil, 17 parts of modified hydrogen-containing silicone oil) and 27.2 parts of white oil to the reaction kettle, heat and stir at 65 °C to obtain base oil;

[0097] S2: Add 1.4 parts of wetting agent (0.6 part of isopropyl alcohol, 0.6 part of propylene glycol, 0.2 part of lauryl alcohol polyoxyethylene ether), 3.4 parts of emulsifier (1.5 parts of polyglycerol fatty acid ester, 1.2 parts of polyoxyethylene fatty alcohol ether, 0.7 part of span 80) to 25 parts of deionized water, stir evenly, heat to 35 °C, then add 0.7 part of rust inhibitor (0.35 part of triethanolamine, 0.35 part of benzotriazole), 0.3 part of defoamer (0.15 part of polydimethylsiloxane, 0.15 part of tributyl phosphate), and continue to stir evenly to obtain a prefabricated emulsion;

[0098] S3: Add the prefabricated emulsion to the base oil and stir evenly to obtain the release agent for centrifugal elbow casting.

[0099] Comparative Example 3: Based on Example 1, the graphene oxide is not modified, and the rest of the process remains unchanged.

[0100] Step 1: Preparation of modified hydrogen-containing silicone oil:

[0101] (1) Preparation of amino-modified talc powder: Add 9 parts of talc powder to 45 parts of deionized water and disperse it evenly by ultrasonic treatment. Add 2.5 parts of amino silane coupling agent, stir at 45 °C for 1.5 h, filter, wash, and dry to obtain amino-modified talc powder;

[0102] (2) Preparation of alkenyl-modified talc powder: Add 9 parts of amino-modified talc powder and 6 parts of 7-octenoic acid to 50 parts of deionized water, ultrasonically disperse evenly, add 2.5 parts of surfactant, stir at 55 °C for 3.5 h, filter, wash, and dry to obtain alkenyl-modified talc powder;

[0103] (3) Preparation of modified hydrogen-containing silicone oil: Add 15 parts of alkenyl-modified talc powder to 11 parts of hydrogen-containing silicone oil, stir evenly, add 0.3 part of catalyst, seal, and stir at 75 °C for 3.5 h to obtain modified hydrogen-containing silicone oil;

[0104] Step 2: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0105] S1: Add 42 parts of modified silicone oil (25 parts of silicone oil, 17 parts of modified hydrogen-containing silicone oil) and 27.2 parts of white oil to the reaction kettle, heat and stir at 65 °C to obtain base oil;

[0106] S2: Add 1.4 parts of wetting agent (0.6 part of isopropyl alcohol, 0.6 part of propylene glycol, 0.2 part of lauryl alcohol polyoxyethylene ether), 3.4 parts of emulsifier (1.5 parts of polyglycerol fatty acid ester, 1.2 parts of polyoxyethylene fatty alcohol ether, 0.7 part of Span 80) to 25 parts of deionized water, stir evenly, heat to 35 °C, then add 0.7 part of rust inhibitor (0.35 part of triethanolamine, 0.35 part of benzotriazole), 0.3 part of defoamer (0.15 part of polydimethylsiloxane, 0.15 part of tributyl phosphate), continue to stir evenly to obtain a prefabricated emulsion;

[0107] S3: Add the prefabricated emulsion to the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0108] Comparative Example 4: Based on Example 1, graphene oxide is not grafted with phosphate ester groups, and the rest of the process remains unchanged.

[0109] Step 1: Preparation of modified hydrogen-containing silicone oil:

[0110] (1) Preparation of amino-modified talc powder: Add 9 parts of talc powder to 45 parts of deionized water, ultrasonically disperse evenly, add 2.5 parts of amino-silane coupling agent, stir at 45 °C for 1.5 h, filter, wash, and dry to obtain amino-modified talc powder;

[0111] (2) Preparation of alkenyl-modified talc powder: Add 9 parts of amino-modified talc powder and 6 parts of 7-octenoic acid to 50 parts of deionized water, ultrasonically disperse evenly, add 2.5 parts of surfactant, stir at 55 °C for 3.5 h, filter, wash, and dry to obtain alkenyl-modified talc powder;

[0112] (3) Preparation of modified hydrogen-containing silicone oil: Add 15 parts of vinyl-modified talc powder to 11 parts of hydrogen-containing silicone oil, stir evenly, add 0.3 part of catalyst, seal, and stir at 75 °C for 3.5 h to obtain modified hydrogen-containing silicone oil;

[0113] Step 2: Preparation of modified graphene oxide:

[0114] (1) Add 4.5 parts of graphene oxide to deionized water and disperse it evenly by ultrasonic treatment. Add 6.5 parts of diaminobutene and 5.5 parts of activator, stir at 55 °C for 2.5 h, add 11 parts of acrylic acid and 0.5 part of initiator, stir at 65 °C for 25 min, filter, wash, and dry to obtain modified graphene oxide.

[0115] Step 3: The preparation method of the release agent for centrifugal elbow casting includes the following steps:

[0116] S1: Add 42 parts of modified silicone oil (25 parts of silicone oil, 17 parts of modified hydrogen-containing silicone oil) and 27.2 parts of white oil to the reaction kettle, heat and stir at 65 °C to obtain the base oil;

[0117] S2: Add 1.4 parts of wetting agent (0.6 part of isopropyl alcohol, 0.6 part of propylene glycol, 0.2 part of lauryl alcohol polyoxyethylene ether), 3.4 parts of emulsifier (1.5 parts of polyglycerol fatty acid ester, 1.2 parts of polyoxyethylene fatty alcohol ether, 0.7 part of Span 80) to 25 parts of deionized water, stir evenly, heat to 35 °C, then add 0.7 part of rust inhibitor (0.35 part of triethanolamine, 0.35 part of benzotriazole), 0.3 part of defoamer (0.15 part of polydimethylsiloxane, 0.15 part of tributyl phosphate), and continue to stir evenly to obtain the prefabricated emulsion;

[0118] S3: Add the prefabricated emulsion to the base oil, stir evenly to obtain the release agent for centrifugal elbow casting.

[0119] Detection test: Select the steel billet of 304 stainless steel as the raw material, add it to the melting furnace, heat it to the molten state to obtain molten steel for standby. Use a horizontal centrifugal casting machine, preheat the inner surface of the mold to 120 °C, add the release agent of the present invention, make it spread evenly on the inner surface of the mold and then pour the molten steel. The rotation speed of the centrifugal casting machine is 1000 revolutions per minute. After centrifugal casting for 20 minutes, when the temperature drops to 800 °C, introduce nitrogen for cooling, and within 10 minutes, reduce the temperature of the steel pipe to 500 °C. After taking it out and carrying out conventional treatment, obtain the test steel pipe. The blank group does not add the release agent, and the rest of the processes remain unchanged. Take the test steel pipe sample for observation, measure the steel pipe sample through an electronic universal testing machine, and use the strength meter. The experimental results are shown in Table 1.

[0120] Table 1

[0121] Project Strength / MPa Surface condition Example 1 1337 The surface is smooth and has no obvious depressions Example 2 1323 The surface is smooth and has no obvious depressions Example 3 1321 The surface is smooth and has no obvious depressions Comparative example 1 1295 The surface is relatively smooth and has 2 pits Comparative example 2 1282 The surface is relatively smooth and has 1 pit Comparative example 3 1260 The surface is relatively smooth and has 2 pits Comparative example 4 1285 The surface is relatively smooth and has no obvious depressions Blank sample 1210 The surface is not smooth and has a small number of pits

[0122] Conclusion: In Comparative Example 1, the talcum powder was not modified, resulting in low dispersibility in the release agent and mediocre demolding effect. In Comparative Example 2, the talcum powder was not grafted with hydrogen-containing silicone oil, and the demolding effect was better than that of Comparative Example 1 but inferior to that of Example 1. In Comparative Example 3, the graphene oxide was not modified, leading to low dispersion effect in the release agent, low demolding effect, and local heat accumulation, resulting in a decrease in the strength of the steel pipe. In Comparative Example 4, the graphene oxide was not grafted with phosphate groups, resulting in a reduction in the film-forming effect of the release agent and a slight decrease in the demolding effect.

[0123] In summary, through the addition of modified silicone oil and modified graphene oxide, the present invention successfully prepared a release agent for centrifugal elbow casting with good demolding effect and high product strength after use.

[0124] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A mold release agent for centrifugal elbow casting, characterized in that The mold release agent for casting comprises the following raw materials, calculated by 100 parts by mass: 35-50 parts of modified silicone oil, 20-30 parts of deionized water, 2-3 parts of modified graphene oxide, 2.5-5 parts of emulsifier, 1-2 parts of wetting agent, 0.5-1 part of rust inhibitor, 0.1-0.5 part of defoamer, and the balance is white oil.

2. The mold release agent for centrifugal elbow casting according to claim 1, wherein: The modified silicone oil comprises the following substances, calculated by mass: 20-30 parts of silicone oil, 15-20 parts of modified hydrogen-containing silicone oil.

3. A demoulding agent for centrifugal elbow casting according to claim 1, characterized in that: The emulsifier comprises the following substances, calculated by mass: 1-2 parts of polyglycerol fatty acid ester, 1-2 parts of polyoxyethylene fatty alcohol ether, 0.5-1 part of Span 80.

4. The release agent for centrifugal elbow casting according to claim 1, characterized in that: The wetting agent comprises the following substances, calculated by mass: 0.5-0.8 part of isopropyl alcohol, 0.4-0.9 part of propylene glycol, 0.1-0.3 part of lauryl alcohol polyoxyethylene ether.

5. The mold release agent for centrifugal bent pipe casting according to claim 1, characterized in that: The rust inhibitor comprises the following substances, calculated by mass: 0.25-0.5 part of triethanolamine, 0.25-0.5 part of benzotriazole; the defoamer comprises the following substances, calculated by mass: 0.05-0.2 part of polydimethylsiloxane, 0.05-0.3 part of tributyl phosphate.

6. The mold release agent for centrifugal elbow casting according to claim 2, wherein: The preparation method of the modified hydrogen-containing silicone oil comprises the following steps: (1) Preparation of amino-modified talc powder: Add talc powder into deionized water and disperse it evenly by ultrasonic wave, add amino-silane coupling agent, stir at 45-50 °C for 1-1.5 h, filter, wash, and dry to obtain amino-modified talc powder; (2) Preparation of alkenyl-modified talc powder: Add amino-modified talc powder and 7-octenoic acid into deionized water and disperse it evenly by ultrasonic wave, add activator, stir at 50-60 °C for 3-4 h, filter, wash, and dry to obtain alkenyl-modified talc powder; (3) Preparation of modified hydrogen-containing silicone oil: Add alkenyl-modified talc powder into hydrogen-containing silicone oil, stir evenly, add catalyst, seal, and stir at 70-80 °C for 3-4 h to obtain modified silicone oil.

7. The mold release agent for centrifugal elbow casting according to claim 6, wherein: The amino-modified talc powder comprises the following raw materials, calculated by mass: 8-10 parts of talc powder, 2-3 parts of amino-silane coupling agent; The alkenyl-modified talc powder comprises the following raw materials, calculated by mass: 8-10 parts of amino-modified talc powder, 5-7 parts of 7-octenoic acid, 2-3 parts of activator; The modified hydrogen-containing silicone oil comprises the following raw materials, calculated by mass: 14-16 parts of alkenyl-modified talc powder, 10-12 parts of hydrogen-containing silicone oil, 0.2-0.4 part of catalyst.

8. A demoulding agent for centrifugal elbow casting according to claim 1, characterized in that: The preparation method of the modified graphene oxide comprises the following steps: (1) Add graphene oxide into deionized water and disperse it evenly by ultrasonic wave, add diaminobutene and activator, stir at 50-60 °C for 2-3 h, add acrylic acid and initiator, stir at 60-70 °C for 20-30 min, filter, wash, and dry to obtain modified graphene oxide A; (2) Add modified graphene oxide A and 6-aminohexyl dihydrogen phosphate into N,N-dimethylformamide, stir evenly, add activator, stir at 50-55 °C for 2-3 h, filter, wash, and dry to obtain modified graphene oxide.

9. A demoulding agent for centrifugal elbow casting according to claim 8, characterized in that: The modified graphene oxide A comprises the following raw materials in parts by mass: 4-5 parts of graphene oxide, 5-8 parts of diamino butene, 5-6 parts of activator, 10-12 parts of acrylic acid, 0.4-0.6 parts of initiator; The modified graphene oxide comprises the following raw materials in parts by mass: 9-11 parts of modified graphene oxide A, 7-8 parts of 6-aminohexyl dihydrogen phosphate, 2-3 parts of activator.

10. The preparation method of a demoulding agent for centrifugal elbow casting according to any one of claims 1 to 9, characterized in that, It comprises the following steps: S1: Add modified silicone oil and white oil into a reaction kettle, and heat and stir at 60-70 °C to obtain base oil; S2: Add a wetting agent and an emulsifier into deionized water, stir evenly, heat to 30-40 °C, then add an anti-rust agent and an anti-foaming agent, and continue to stir evenly to obtain a prefabricated emulsion; S3: Add the prefabricated emulsion into the base oil, stir evenly to obtain a demoulding agent for centrifugal elbow casting.