Isocyanate curing agent and preparation method thereof
An isocyanate curing agent was prepared by combining an oxyacid polymerization inhibitor, an ester solvent, and a polyol ester modifier. This solved the problems of isocyanate self-polymerization and water reaction, improved storage stability and the performance of cast steel parts, and reduced production costs.
Patent Information
- Application Number
- CN202511563077.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-30
- Publication Date
- 2026-01-23
AI Technical Summary
Isocyanate curing agents are prone to self-polymerization at room temperature or low temperature, which affects product performance and storage stability. They also readily react with water to generate substances such as carbon dioxide. Existing methods for inhibiting polymerization are either ineffective or costly.
An isocyanate curing agent is prepared by combining an oxyacid polymerization inhibitor, an ester organic compound solvent, and a polyol ester modifier through a specific process. This process inhibits the self-polymerization reaction and establishes a chemical environment to prevent reaction with water.
It significantly improves storage stability, reduces polymer formation, enhances the mechanical and curing properties of cast steel parts, lowers production costs, and meets environmental protection requirements.
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of foundry auxiliary materials, in particular to an isocyanate curing agent and a preparation method thereof. BACKGROUND
[0002] In recent years, in the field of cast steel production, a new type of alcohol acid system environmental protection binder is introduced, and the curing agent used in conjunction with it belongs to the isocyanate product. Because the isocyanate group (-NCO) in the molecular structure of isocyanate is highly active, even at room temperature or even low temperature, it is easy to occur self-polymerization reaction to generate dimers, trimers and other polymers, which will lead to the quality decline of isocyanate curing agent product, and further affect the product performance and subsequent processing of castings. In addition, isocyanate is also easy to react with water to generate carbon dioxide and other substances, which will weaken the use performance and storage stability of isocyanate curing agent product. At present, although there are some methods to inhibit the self-polymerization of isocyanate, but there are generally problems such as poor inhibition effect, large addition amount which affects product performance or cost, and so on. SUMMARY
[0003] Based on this, in order to solve the above technical problems, the present application provides an isocyanate curing agent which is efficient, low cost and has little effect on the performance of isocyanate, so as to produce an isocyanate curing agent product for cast steel with long shelf life and stable quality.
[0004] In order to solve the above technical problems, the present application adopts the following technical scheme:
[0005] An isocyanate curing agent, by weight, comprising 100 parts of isocyanate, 0.03-0.11 parts of oxygen-containing acid polymerization inhibitor, 8-35 parts of ester organic compound solvent and 0.10-0.16 parts of polyol ester modifier.
[0006] Further, the isocyanate is at least one of toluene diisocyanate, diphenyl methane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexyl methane diisocyanate and lysine diisocyanate.
[0007] Further, the oxygen-containing acid polymerization inhibitor is at least one of metasilicic acid, metaphosphoric acid, carbonic acid, boric acid, perchloric acid, chloric acid and hypochlorous acid.
[0008] Further, the ester organic compound solvent is at least one of butyl acetate, butyl formate, isobutyl formate, isoamyl butyrate, isoamyl acetate, butyl butyrate, phenethyl acetate and phenethyl butyrate.
[0009] Further, the purity of the ester organic compound solvent is not less than 99%.
[0010] Further, the polyol ester modifier is at least one of glyceryl triacetate, dihydric alcohol fatty acid ester, dipentaerythritol ester, dihydric alcohol benzoic acid ester.
[0011] In a second aspect, the application also provides a preparation method, which is applied to the isocyanate curing agent described above.
[0012] S1, the isocyanate is added into a reaction kettle, and stirring is started;
[0013] S2, the oxygen-containing acid polymerization inhibitor is added into the reaction kettle, and the temperature is slowly increased to 48-52℃;
[0014] S3, the ester organic compound solvent is added into the reaction kettle;
[0015] S4, the reaction kettle is heated to 60-65℃, and the isocyanate and the oxygen-containing acid polymerization inhibitor are allowed to react completely for 1.4-1.6h;
[0016] S5, after the reaction is completed, the reaction kettle is cooled to 32-38℃, the polyol ester modifier is added, and stirring is performed for more than 30min, so that the isocyanate curing agent is prepared.
[0017] Further, in the S3 step, the ester organic compound solvent is added into the reaction kettle at a uniform speed by using a dropping device, and the dropping time is 30±1min; during the dropping process, the temperature of the reaction kettle is maintained at 48-52℃.
[0018] Further, the ester organic compound solvent is subjected to a dehydration treatment in advance, and the water content is not higher than 0.1%.
[0019] Further, the stirring rate of the reaction kettle is 60-90r / min.
[0020] Compared with the prior art, the method has the following beneficial effects:
[0021] The isocyanate curing agent disclosed in the application can effectively inhibit the self-polymerization reaction of the isocyanate by adding an appropriate amount of oxygen-containing acid as a polymerization inhibitor, can establish a chemical environment that inhibits the reaction with water in the isocyanate system, effectively prevents the chemical reaction between the isocyanate and water, reduces the generation of carbon dioxide gas, avoids defects such as bubbles and blistering of the product, and improves the appearance quality of the product. Experimental results show that under the same storage conditions (temperature 25℃, relative humidity 50%), after the isocyanate composition added with the polymerization inhibitor of the application is stored for 6 months, the content of the polymer produced by self-polymerization is less than 3%, while the content of the isocyanate self-polymerization polymer without adding the polymerization inhibitor can reach more than 10%, which significantly improves the storage stability of the isocyanate.
[0022] The isocyanate curing agent disclosed by the application has simple preparation process operation, does not need special equipment and complex process conditions, is easy to industrialize, and can complete production in 3-4 hours per batch, which can shorten the general time compared with the existing technology in the industry and has high production efficiency. Meanwhile, the oxygen-containing acid has relatively low price and wide source, can effectively improve the product performance, does not significantly increase the production cost, has good economic benefits, and has no special toxicity and volatile pollution for the oxygen-containing acid polymerization inhibitor and the ester organic compound solvent, is friendly to the environment in the production and use process, meets the environmental protection requirements, and guarantees the health and safety of the operators.
[0023] The isocyanate curing agent disclosed by the application is used for cast steel casting production, and the mechanical properties and curing performance are obviously improved. In the actual molding process, compared with the unmodified isocyanate curing agent, the mold sand strength of the isocyanate curing agent is increased by more than 10%, and the sand mold curing and stripping time is shortened by about 15%. DETAILED DESCRIPTION
[0024] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related embodiments. The embodiments give the preferred embodiments of the present application. However, the present application can be realized in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0026] One of the purposes of the present application is to disclose an isocyanate curing agent, comprising, by weight parts, 100 parts of isocyanate, 0.03-0.11 parts of oxygen acid polymerization inhibitor, 8-35 parts of ester organic compound solvent and 0.10-0.16 parts of polyol ester modifier. Among them, the isocyanate is selected from common isocyanates such as toluene diisocyanate (TDI), diphenyl methane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexyl methane diisocyanate (HMDI), lysine diisocyanate (LDI) and combinations thereof. Considering the reaction activity, product performance and application range, the impurity content is low, which can ensure the smooth progress of the main reaction, reduce unnecessary side reactions caused by impurities, and thus improve the product quality and stability. Oxygen acid is used as the main polymerization inhibitor. Oxygen acid can react with the active intermediates produced during the self-polymerization of isocyanate, block the chain growth of self-polymerization, effectively inhibit the self-polymerization of isocyanate, and at the same time, oxygen acid can effectively inhibit the side reaction of isocyanate with water, and has little effect on the main reaction involving isocyanate. The oxygen acid polymerization inhibitor can be at least one of metasilicic acid (H2SiO3), metaphosphoric acid (HPO3), carbonic acid (H2CO3), boric acid (H3BO3), perchloric acid (HClO4), chloric acid (HClO3), hypochlorous acid (HClO). Selecting ester organic compound as the solvent, it has good solubility to isocyanate and oxygen acid, can effectively adjust the viscosity of the reaction system, can make the reaction system uniformly dispersed, and promote the reaction. The ester organic compound solvent can be at least one of butyl acetate, butyl formate, isobutyl formate, isoamyl butyrate, isoamyl acetate, butyl butyrate, phenethyl acetate, phenethyl butyrate. Selecting polyol ester as the modifier, further improving the weather resistance of the curing agent product, and supporting the strength and mechanical properties of the resin product. The polyol ester modifier can be at least one of glycerol triacetate, dihydric alcohol fatty acid ester, dipentaerythritol ester, dihydric alcohol benzoate.
[0027] The purity of isocyanate is not less than 99%. The ester organic compound solvent needs to be dehydrated in advance, and the purity is not less than 99%, and the water content is not higher than 0.1%.
[0028] The second purpose of the present application is to disclose a preparation method of the above-mentioned isocyanate curing agent. The isocyanate curing agent is prepared in a reaction kettle equipped with a condenser, a heating device, a thermometer, a stirring device and a dropping device. The preparation method can include the following steps:
[0029] S1, 100 parts of isocyanate are added to the reaction kettle, and stirring is started to make the isocyanate fully dispersed. The stirring speed can be 60-90 r / min, which can ensure the dispersion effect and avoid wrapping gas bubbles into the liquid material to affect the product quality.
[0030] S2. Add 0.03–0.11 parts of oxyacid polymerization inhibitor to the reactor and slowly heat to 48–52°C. The heating rate can be controlled at 1–2°C / min, which ensures production efficiency and avoids product quality fluctuations caused by excessively rapid heating or uneven local heating.
[0031] S3. Using a dropping device, 8–35 parts of pre-dehydrated ester-based organic compound solvent are added dropwise to the reaction vessel at a uniform rate. During the dropping process, the temperature of the reaction vessel is maintained at 48–52°C. The dropping time can be controlled to 30 ± 1 min, which ensures both production efficiency and maintains the liquid temperature within the range of 48–52°C throughout the solvent dropping process.
[0032] S4. The reactor is heated to 60-65°C at a rate of 1-2°C / min and held at that temperature for 1.4-1.6 hours to allow the isocyanate and the oxyacid polymerization inhibitor to react fully and completely.
[0033] S5. After the reaction is completed, the reaction vessel is cooled to 32-38°C with cold water, and 0.10-0.16 parts of polyol ester modifier are added. The mixture is stirred for more than 30 minutes to obtain the isocyanate curing agent of the present invention.
[0034] Example 1
[0035] An isocyanate curing agent, by weight, comprises 100 parts isocyanate, 0.03 parts oxyacid polymerization inhibitor, 8 parts ester organic compound solvent and 0.1 parts polyol ester modifier.
[0036] The preparation method of this isocyanate curing agent may include the following steps:
[0037] S1. Add 100 parts of isocyanate to the reaction vessel and start stirring to fully disperse the isocyanate. The stirring speed can be 70 r / min.
[0038] S2. Add 0.03 parts of oxyacid polymerization inhibitor to the reactor and slowly heat to 50°C. The heating rate can be controlled at 1-2°C / min.
[0039] S3. Using a dropping device, 8 parts of pre-dehydrated ester organic compound solvent are added dropwise to the reaction vessel at a uniform rate. During the dropping process, the temperature of the reaction vessel is maintained at 48–52°C.
[0040] S4. The reactor is heated to 60°C at a rate of 1-2°C / min and held at that temperature for 1.5 hours.
[0041] S5. After the reaction is complete, the reaction vessel is cooled to 35°C with cold water, 0.1 parts of polyol ester modifier are added, and the mixture is stirred for more than 30 minutes to obtain the isocyanate curing agent of this embodiment.
[0042] The storage period of the product of the embodiment is 60 days detected by sampling. The sand mixed with the binder and the curing agent of the embodiment can be used for 21 min for silica sand and 28 min for chrome ore sand. The 24 h compressive strength of the silica sand is 2.9 MPa, and the 24 h compressive strength of the chrome ore sand is 6.15 MPa.
[0043] Embodiment Two
[0044] An isocyanate curing agent includes, by weight parts, 100 parts of toluene diisocyanate, 0.07 parts of metasilicic acid, 22 parts of butyl acetate, and 0.13 parts of glycerol triacetate.
[0045] The preparation method of the isocyanate curing agent can include the following steps:
[0046] S1, 100 parts of toluene diisocyanate is added to the reaction kettle, and stirring is started. The stirring speed can be 90 r / min.
[0047] S2, 0.07 parts of metasilicic acid is added to the reaction kettle, and the temperature is slowly raised to 52℃. The temperature raising rate can be controlled at 1-2℃ / min.
[0048] S3, 22 parts of pre-dehydrated butyl acetate is uniformly added to the reaction kettle by using a dropping device. During the dropping process, the temperature of the reaction kettle is maintained at 48-52℃.
[0049] S4, the reaction kettle is heated at a rate of 1-2℃ / min to 65℃, and kept for 1.4 h.
[0050] S5, after the reaction is completed, the reaction kettle is cooled to 35℃ with cold water, 0.13 parts of glycerol triacetate is added, and stirring is performed for more than 30 min, to obtain the isocyanate curing agent of the embodiment.
[0051] The storage period of the product of the embodiment is 72 days detected by sampling. The sand mixed with the binder and the curing agent of the embodiment can be used for 23 min for silica sand and 35 min for chrome ore sand. The 24 h compressive strength of the silica sand is 2.68 MPa, and the 24 h compressive strength of the chrome ore sand is 5.8 MPa.
[0052] Embodiment Three
[0053] An isocyanate curing agent includes, by weight parts, 100 parts of toluene diisocyanate, 0.07 parts of metasilicic acid, 22 parts of butyl acetate, and 0.13 parts of glycerol triacetate.
[0054] The preparation method of the isocyanate curing agent can include the following steps:
[0055] S1, 100 parts of diphenyl methane diisocyanate, open stirring. The stirring speed can be 80 r / min.
[0056] S2, the reactor is added 0.11 parts of hypochlorous acid, slowly heated to 50 DEG C. The heating rate can be controlled at 1~2 DEG C / min.
[0057] S3, using a dropping device to the reactor uniform speed drop 35 parts of pre-dehydration of butyl isopentyl. In the process of drop, the temperature of the reactor is maintained at 48~52 DEG C.
[0058] S4, the reactor is heated to 65 DEG C at a rate of 1~2 DEG C / min, 1.5 h.
[0059] S5, after the reaction, the reactor with cold water cooling to 35 DEG C, add 0.16 parts of dihydric alcohol benzoate, stirring 30 min or more, can be prepared in this embodiment isocyanate curing agent.
[0060] Sampling detection, the product of this embodiment is 90 days. With alcohol adhesive production sand, detection mixed with adhesive and the sand of this embodiment curing agent can be used time, wherein, silica sand is 26 min, chrome sand is 45 min; silica sand 24 h compressive strength is 2.52 MPa, chrome sand 24 h compressive strength is 5.56 MPa.
[0061] Example four
[0062] An isocyanate curing agent, by weight, including, 100 parts of isocyanate, 0.08 parts of oxygen acid polymerization inhibitor, 10 parts of ester organic compound solvent and 0.16 parts of polyol ester modifier.
[0063] The preparation method of the isocyanate curing agent can include the following steps:
[0064] S1, 100 parts of isocyanate is added to the reactor, open stirring, so that the isocyanate is fully dispersed. The stirring speed can be 80 r / min.
[0065] S2, the reactor is added 0.08 parts of oxygen acid polymerization inhibitor, slowly heated to 50 DEG C. The heating rate can be controlled at 1~2 DEG C / min.
[0066] S3, using a dropping device to the reactor uniform speed drop 10 parts of pre-dehydration of ester organic compound solvent. In the process of drop, the temperature of the reactor is maintained at 48~52 DEG C.
[0067] S4, the reactor is heated to 63 DEG C at a rate of 1~2 DEG C / min, 1.5 h.
[0068] S5, after the reaction, the reactor is cooled to 35℃ with cold water, 0.16 parts of polyol ester modifier is added, and stirring is performed for more than 30 min, to obtain the isocyanate curing agent of the example.
[0069] The storage period of the product of the example is 65 days. The sand mixed with the binder and the curing agent of the example is used to make a sand mold, and the service time of the sand mixed with the binder and the curing agent of the example is detected, wherein the service time of the silica sand is 18 min, and the service time of the chrome ore sand is 25 min; the 24 h compressive strength of the silica sand is 3.05 MPa, and the 24 h compressive strength of the chrome ore sand is 6.48 MPa.
[0070] Example Five
[0071] An isocyanate curing agent includes, by weight, 100 parts of dicyclohexyl methane diisocyanate, 0.1 parts of metaphosphoric acid, 25 parts of butyl formate, and 0.12 parts of glycerol triacetate.
[0072] The preparation method of the isocyanate curing agent can include the following steps:
[0073] S1, 100 parts of dicyclohexyl methane diisocyanate is added to the reactor, and stirring is started. The stirring speed can be 90 r / min.
[0074] S2, 0.1 parts of metaphosphoric acid is added to the reactor, and the temperature is slowly raised to 50℃. The temperature raising rate can be controlled at 1-2℃ / min.
[0075] S3, 25 parts of pre-dehydrated butyl formate is uniformly added to the reactor at a constant speed by using a dropping device. During the dropping process, the temperature of the reactor is maintained at 48-52℃.
[0076] S4, the reactor is heated to 65℃ at a rate of 1-2℃ / min, and the temperature is maintained for 1.5 h.
[0077] S5, after the reaction, the reactor is cooled to 35℃ with cold water, 0.12 parts of glycerol triacetate is added, and stirring is performed for more than 30 min, to obtain the isocyanate curing agent of the example.
[0078] The storage period of the product of the example is 75 days. The sand mixed with the binder and the curing agent of the example is used to make a sand mold, and the service time of the sand mixed with the binder and the curing agent of the example is detected, wherein the service time of the silica sand is 20 min, and the service time of the chrome ore sand is 40 min; the 24 h compressive strength of the silica sand is 2.78 MPa, and the 24 h compressive strength of the chrome ore sand is 6.05 MPa.
[0079] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.
Claims
1. An isocyanate curing agent, characterized by, The isocyanate is at least one of toluene diisocyanate, diphenyl methane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexyl methane diisocyanate, and lysine diisocyanate.
2. The isocyanate curing agent according to claim 1, characterized in that, The ester organic compound solvent is at least one of butyl acetate, butyl formate, isobutyl formate, isoamyl butyrate, isoamyl acetate, butyl butyrate, phenethyl acetate, and phenethyl butyrate.
3. The isocyanate curing agent according to claim 1, characterized in that, The purity of the ester organic compound solvent is not less than 99%.
4. The isocyanate curing agent according to claim 1, characterized by The polyol ester modifier is at least one of glycerol triacetate, dihydric alcohol fatty acid ester, dipentaerythritol ester, and dihydric alcohol benzoic acid ester.
5. The isocyanate curing agent according to claim 4, characterized in that, The preparation method comprises the following steps:
6. The isocyanate curing agent according to claim 1, characterized in that, S1, the isocyanate is added to a reaction kettle, and stirring is started; 7. A production method for the isocyanate curing agent according to any one of claims 1 to 6, characterized by, S2, the oxygen acid polymerization inhibitor is added to the reaction kettle, and the temperature is slowly raised to 48-52°C; S3, the ester organic compound solvent is added to the reaction kettle; S4, the reaction kettle is heated to 60-65°C, and the temperature is maintained for 1.4-1.6 hours to make the isocyanate and the oxygen acid polymerization inhibitor fully react; S5, after the reaction is completed, the reaction kettle is cooled to 32-38°C, the polyol ester modifier is added, and stirring is performed for 30 minutes or more, so that the isocyanate curing agent is prepared. In the S3 step, the ester organic compound solvent is uniformly added to the reaction kettle at a constant speed by using a dropping device, and the dropping time is 30±1 minutes; During the dropping process, the temperature of the reaction kettle is maintained at 48-52°C.
8. The preparation method according to claim 7, characterized in that, The ester organic compound solvent is pre-treated by dehydration, and the water content is not higher than 0.1%. The stirring rate of the reaction kettle is 60-90 r / min.
9. The preparation method according to claim 7, characterized in that, 10. The preparation method according to claim 7, characterized in that,