Method for producing high-activity and high-melting-point isocyanate prepolymer and product thereof in small batch

Abstract

The invention relates to a method for producing a high-activity and high-melting-point isocyanate prepolymer and a product thereof in small batches, and belongs to the technical field of chemical synthesis. The method for producing the high-activity and high-melting-point isocyanate prepolymer in small batches comprises the following steps: S1, pretreating raw materials; s2, adding the pretreated raw materials into a planetary centrifugal mixer; s3, starting the planetary centrifugal mixer to carry out a mixing reaction; and S4, starting a vacuum system of the planetary centrifugal mixer, and continuing the mixing reaction to obtain the isocyanate prepolymer. According to the invention, rapid and uniform mixing of materials is ensured by utilizing the strong shearing and mixing effect of the planetary centrifugal mixer, defoaming and rapid cooling are realized by utilizing a vacuum system of the equipment, the mixing efficiency and reaction temperature in the preparation process of the prepolymer are effectively controlled, no dead angle in mixing is ensured, and side reactions such as self-polymerization caused by too high temperature are avoided; and the stability of the molecular structure of the prepolymer and the consistency of the product quality are ensured.

Description

Technical Field

[0001] The invention relates to a method for producing a high-activity and high-melting-point isocyanate prepolymer and its products in small batches, belonging to the technical field of chemical synthesis. Background Art

[0002] Paraphenylene diisocyanate (PPDI), diphenylmethane diisocyanate (NDI), and dimethyldiphenyl diisocyanate (TODI) are all highly reactive isocyanates with high melting points. Taking NDI as an example, NDI prepolymer is an important polymer intermediate widely used in polyurethane elastomers, coatings, adhesives, and other fields. Traditional prepolymer preparation methods present numerous challenges in small-batch production. Firstly, temperature control is difficult during the reaction. The NDI prepolymer synthesis reaction is exothermic. Failure to effectively and timely control the reaction temperature can easily lead to excessively high temperatures in the reaction system, triggering side reactions and affecting the molecular structure and performance stability of the prepolymer. Secondly, traditional mixing equipment has low mixing efficiency, making it difficult to ensure sufficient and uniform mixing of materials in small-batch production, resulting in variable prepolymer quality. Furthermore, in traditional processes, after NDI prepolymer preparation, the prepolymer must be transferred to other equipment before adding a curing agent for product preparation. This increases production steps and time costs, and impurities are easily introduced during the transfer process, affecting product quality. Similarly, the production and processing of PPDI and TODI systems present similar challenges as NDI. In addition, the traditional prepolymer synthesis method has the disadvantages of low heat transfer efficiency and slow cooling speed.

[0003] Therefore, there is an urgent need to develop a small-batch production method that can effectively control the reaction temperature, improve the mixing efficiency, and integrate the preparation of highly active and high-melting-point isocyanate prepolymers with the preparation of finished products. Summary of the Invention

[0004] The object of the present invention is to provide a method for small-batch production of highly active and high-melting-point isocyanate prepolymers and products thereof. By adopting the high-shear and high-efficiency mixing function of a planetary centrifugal mixer and utilizing its vacuum rapid cooling function, the present invention solves the problems of difficult reaction temperature control, low mixing efficiency, and complicated production procedures in the prior art, thereby achieving stable preparation of highly active and high-melting-point isocyanate prepolymers and rapid and efficient product production, thereby improving product quality and production efficiency.

[0005] The technical solutions provided by the present invention are as follows: One of the objects of the present invention is to provide a method for producing a high-activity, high-melting-point isocyanate prepolymer in small batches, comprising the following steps: S1: Dehydrate the polyol to a moisture content of <0.05%, and crush the highly active and high melting point isocyanate monomer into small particles with a particle size of <2 mm; S2: After heating the dehydrated polyol to 80-140°C, add it to a planetary centrifugal mixer, and then add a highly active and high melting point isocyanate monomer; S3: Start the planetary centrifugal mixer and mix and react for 6 to 20 minutes at an orbital speed of 500 to 1500 rpm and an autorotational speed of 800 to 3000 rpm; S4: starting the vacuum system of the planetary centrifugal mixer and continuing the mixing reaction for 2 to 6 minutes to obtain the highly active and high melting point isocyanate prepolymer.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows: Furthermore, in step S2, the mass ratio of the polyol to the highly active and high melting point isocyanate monomer is 100:25-41.

[0007] Furthermore, in step S4, the vacuum value of the vacuum system is -0.08 to -0.1 MPa.

[0008] Furthermore, the highly active and high melting point isocyanate monomer is one or more of naphthalene diisocyanate (NDI), diphenyl diisocyanate (TODI) and p-phenylene diisocyanate (PPDI).

[0009] Furthermore, the polyol is one or more of polysuccinate polyol, adipic acid polyol, sebacate polyol, polycaprolactone polyol, polycarbonate polyol, polytetramethylene glycol and butadiene glycol, and the hydroxyl value of the polyol is 28-224.4 and the molecular weight range is 500-4000.

[0010] The second object of the present invention is to provide a highly active and high melting point isocyanate prepolymer, which is prepared by the method for producing highly active and high melting point isocyanate prepolymer in small batches.

[0011] A third object of the present invention is to provide a method for producing a high-activity, high-melting-point isocyanate prepolymer product in small batches, comprising the following steps: S1: Dehydrate the polyol to a moisture content of <0.05%, and crush the highly active and high melting point isocyanate monomer into small particles with a particle size of <2 mm; S2: Heat the dehydrated polyol to 80-140°C, add it to a planetary centrifugal mixer, and then add a highly active and high melting point isocyanate monomer; S3: Start the planetary centrifugal mixer and mix and react for 6 to 20 minutes at an orbital speed of 500 to 1500 rpm and an autorotational speed of 800 to 3000 rpm; S4: Start the vacuum system of the planetary centrifugal mixer and continue the mixing reaction for 2 to 6 minutes to obtain a highly active and high melting point isocyanate prepolymer; S5: adding a curing agent to the obtained special high-activity and high-melting-point isocyanate prepolymer, turning on the planetary centrifugal vacuum mixer again, vacuum mixing the mixture evenly, and then injecting the mixture into a mold for curing and molding to obtain the high-activity and high-melting-point isocyanate prepolymer product.

[0012] Furthermore, the added mass of the curing agent is 2-15% of the mass of the highly active and high melting point isocyanate prepolymer.

[0013] Furthermore, the curing agent is at least one of amine, diol, and triol chain extenders.

[0014] Furthermore, the curing agent is one or more of ethylene glycol, butanediol, hydroquinone dihydroxyethyl ether (HQEE), resorcinol dihydroxyethyl ether (HER), trimethylolpropane, di-o-chlorodiphenylmethane (MOCA) and dimethylthiotoluenediamine (E300).

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1. The planetary centrifugal mixer of the present invention can achieve rapid and sufficient mixing of materials in small batch production under the action of high-speed shearing, greatly improving the mixing efficiency, ensuring the uniformity of the prepolymer, and improving the quality of the product.

[0016] 2. The present invention utilizes the vacuum system of the planetary centrifugal mixer to achieve rapid cooling, which can effectively control the reaction temperature during the prepolymer preparation process, avoid side reactions such as self-polymerization caused by excessively high temperature, and ensure the stability of the prepolymer molecules.

[0017] 3. After the preparation of the highly active and high-melting-point isocyanate prepolymer of the present invention is completed, a curing agent can be directly added to the same equipment to prepare the product, thereby realizing the integration of prepolymer preparation and product production, reducing the production process and material transfer process, reducing production time cost and the risk of introducing impurities, and improving production efficiency and product qualification rate. DETAILED DESCRIPTION

[0018] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. Example 1

[0019] A method for producing NDI prepolymers and products thereof in small batches comprises the following steps: S1: Dehydrate polytetramethylene glycol (hydroxyl value 112.2, molecular weight 1000) to a moisture content of <0.05%, and crush the NDI monomer into small particles with a particle size of <2 mm; S2: 1000 g of dehydrated polytetrahydrofuran diol was heated to 135° C. and added to a planetary centrifugal mixer, followed by rapid addition of 407 g of NDI monomer; S3: Start the planetary centrifugal mixer and perform mixing reaction at an orbital speed of 1000 rpm and a rotational speed of 900 rpm for 6 minutes; S4: starting the vacuum system of the planetary centrifugal mixer, evacuating to -0.1 MPa, and continuing centrifugal mixing for 6 minutes to obtain the NDI prepolymer; S5: adding 75 g of 1.4-butanediol to the NDI prepolymer, turning on the planetary centrifugal mixer again, mixing evenly, and injecting into a mold for curing and molding to obtain the NDI prepolymer product. Example 2

[0020] A method for producing NDI prepolymers and products thereof in small batches comprises the following steps: S1: Dehydrate polycaprolactone diol (hydroxyl value 56.1, molecular weight 2000) to a moisture content of <0.05%, and crush NDI monomer into small particles with a particle size of <2 mm; S2: 1000 g of dehydrated polycaprolactone diol was heated to 135°C and added to a planetary centrifugal mixer, followed by rapid addition of 258 g of NDI monomer; S3: Start the planetary centrifugal mixer and perform mixing reaction at an orbital speed of 1000 rpm and a rotational speed of 1000 rpm for 8 minutes; S4: starting the vacuum system of the planetary centrifugal mixer, evacuating to -0.1 MPa, and continuing centrifugal mixing for 6 minutes to obtain the NDI prepolymer; S5: 59 g of 1.4-butanediol was added to the NDI prepolymer, and the planetary centrifugal mixer was turned on again. After mixing evenly, the mixture was injected into a mold for curing and molding to obtain the NDI prepolymer product. Example 3

[0021] A method for producing PPDI prepolymers and products thereof in small batches comprises the following steps: S1: Dehydrate polytetramethylenediol (hydroxyl value 112.2, molecular weight 1000) to a moisture content of <0.05%, and crush the PPDI monomer into small particles with a particle size of <2 mm; S2: 1000 g of dehydrated polytetrahydrofuran diol was heated to 80° C. and added to a planetary centrifugal mixer, followed by rapid addition of 315 g of PPDI monomer; S3: Start the planetary centrifugal mixer and perform mixing reaction at an orbital speed of 1000 rpm and a rotational speed of 1000 rpm for 20 minutes; S4: starting the vacuum system of the planetary centrifugal mixer, evacuating the mixture to -0.08 MPa, and continuing centrifugal mixing for 2 minutes to obtain the PPDI prepolymer; S5: 162 g of HER was added to the PPDI prepolymer, and the planetary centrifugal mixer was turned on again. After mixing evenly, the mixture was injected into a mold for curing and molding to obtain the NDI prepolymer product. Example 4

[0022] A method for producing TODI prepolymer and its products in small batches comprises the following steps: S1: Dehydrate polycaprolactone diol (hydroxyl value 56.1, molecular weight 2000) to a moisture content of <0.05%, and crush TODI monomer into small particles with a particle size of <2 mm; S2: 1000 g of dehydrated polycaprolactone diol was heated to 120°C and added to a planetary centrifugal mixer, followed by rapid addition of 265 g of TODI monomer; S3: Start the planetary centrifugal mixer and perform mixing reaction at an orbital speed of 1000 rpm and a rotational speed of 1000 rpm for 10 minutes; S4: starting the vacuum system of the planetary centrifugal mixer, evacuating the mixture to -0.09 MPa, and continuing centrifugal mixing for 6 minutes to obtain the TODI prepolymer; S5: 132 g of MOCA was added to the TODI prepolymer, and the planetary centrifugal mixer was turned on again. After mixing evenly, the mixture was injected into a mold for curing and molding to obtain the TODI prepolymer product.

[0023] Comparative Example 1: A method for producing NDI prepolymers and products thereof in small batches comprises the following steps: S1: Dehydrate polytetramethylene glycol (hydroxyl value 112.2, molecular weight 1000) to a moisture content of <0.05%, and crush the NDI monomer into small particles with a particle size of <2 mm; S2, add 1000g of dehydrated polytetrahydrofuran diol into a 2000ml stainless steel cup, heat to 130°C, and quickly add 407g of NDI; S3, using a stirrer to stir at high speed for 15 minutes to carry out a mixing reaction; S4, standing and cooling to 85°C to obtain NDI prepolymer; S5. Add 75 g of 1.4-butanediol to the NDI prepolymer, stir rapidly to degas, and then pour into a mold to obtain an NDI prepolymer product.

[0024] Comparative Example 2 A method for producing NDI prepolymers and products thereof in small batches comprises the following steps: S1: Dehydrate polytetramethylene glycol (hydroxyl value 112.2, molecular weight 1000) to a moisture content of <0.05%, and crush the NDI monomer into small particles with a particle size of <2 mm; S2: 1000 g of dehydrated polytetrahydrofuran diol was heated to 135° C. and added to a planetary centrifugal mixer, followed by rapid addition of 407 g of NDI monomer; S3: Start the planetary centrifugal mixer and perform mixing reaction at an orbital speed of 400 rpm and an autorotational speed of 600 rpm. After 8 minutes of reaction, start the vacuum system of the planetary centrifugal mixer, evacuate to -0.1 MPa, and continue vacuum centrifugal mixing for 3 minutes; S4: starting the vacuum system of the planetary centrifugal mixer, evacuating to -0.1 MPa, and continuing centrifugal mixing for 6 minutes to obtain the NDI prepolymer; S5: adding 75 g of 1.4-butanediol to the NDI prepolymer, turning on the planetary centrifugal mixer again, mixing evenly, and injecting into a mold for curing and molding to obtain the NDI prepolymer product.

[0025] Comparative Example 3 A method for producing PPDI prepolymers and products thereof in small batches comprises the following steps: S1: Dehydrate polytetramethylenediol (hydroxyl value 112.2, molecular weight 1000) to a moisture content of <0.05%, and crush the PPDI monomer into small particles with a particle size of <2 mm; S2: 1000 g of dehydrated polytetrahydrofuran diol was heated to 80° C. and added to a planetary centrifugal mixer, followed by rapid addition of 315 g of PPDI monomer; S3: Start the planetary centrifugal mixer and perform mixing reaction at an orbital speed of 300 rpm and an autorotational speed of 600 rpm for 20 minutes; S4: starting the vacuum system of the planetary centrifugal mixer, evacuating to -0.1 MPa, and continuing centrifugal mixing for 2 minutes to obtain the PPDI prepolymer; S5: 162 g of HER was added to the PPDI prepolymer, and the planetary centrifugal mixer was turned on again. After mixing evenly, the mixture was injected into a mold for curing and molding to obtain the NDI prepolymer product.

[0026] Performance testing: The prepolymer products obtained in Examples 1-4 and Comparative Examples 1-3 were subjected to performance tests.

[0027] The results are shown in Table 1.

[0028] Table 1 Performance test data table

[0029] As can be seen from Table 1, Examples 1-4 are superior to Comparative Examples 1-3 in hardness, tensile strength, tear strength, elongation, rebound rate and compression permanent deformation rate, indicating that the products obtained by the preparation method of the present invention have better mechanical strength, elasticity and durability.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for producing a high-activity and high-melting-point isocyanate prepolymer in small batches, characterized in that: The following steps are involved: S1: Dehydrate the polyol to a moisture content of <0.05%, and crush the highly active and high melting point isocyanate monomer into small particles with a particle size of <2 mm; S2: Heat the dehydrated polyol to 80-140°C, add it to a planetary centrifugal mixer, and then add a highly active and high melting point isocyanate monomer; S3: Start the planetary centrifugal mixer and mix and react for 6 to 20 minutes at an orbital speed of 500 to 1500 rpm and an autorotational speed of 800 to 3000 rpm; S4: starting the vacuum system of the planetary centrifugal mixer and continuing the mixing reaction for 2 to 6 minutes to obtain the highly active and high melting point isocyanate prepolymer.

2. The method for producing a high-activity and high-melting-point isocyanate prepolymer in small batches according to claim 1, characterized in that: In step S2, the mass ratio of the polyol to the highly active and high melting point isocyanate monomer is 100:25-41.

3. The method for producing a high-activity and high-melting-point isocyanate prepolymer in small batches according to claim 1, wherein: In step S4, the vacuum value of the vacuum system is -0.08 to -0.1 MPa.

4. The method for producing a high-activity and high-melting-point isocyanate prepolymer in small batches according to claim 1, wherein: The isocyanate monomer with high activity and high melting point is one or more of naphthalene diisocyanate, biphenyl diisocyanate and p-phenylene diisocyanate.

5. The method for producing high-activity and high-melting-point isocyanate prepolymers in small batches according to claim 1, characterized in that: The polyol is one or more of polysuccinate polyol, adipic acid polyol, sebacate polyol, polycaprolactone polyol, polycarbonate polyol, polytetramethylene glycol and butadiene glycol. The hydroxyl value of the polyol is 28-224.4 and the molecular weight range is 500-4000.

6. A highly active and high melting point isocyanate prepolymer, characterized in that: The isocyanate prepolymer is prepared by the method for producing high-activity and high-melting-point isocyanate prepolymer in small batches as described in any one of claims 1 to 5.

7. A method for producing high-activity and high-melting-point isocyanate prepolymer products in small batches using the isocyanate prepolymer according to claim 6, characterized in that: The steps include: S1: Dehydrate the polyol to a moisture content of <0.05%, and crush the highly active and high melting point isocyanate monomer into small particles with a particle size of <2 mm; S2: Heat the dehydrated polyol to 80-140°C, add it to a planetary centrifugal mixer, and then add a highly active and high melting point isocyanate monomer; S3: Start the planetary centrifugal mixer and mix and react for 6 to 20 minutes at an orbital speed of 500 to 1500 rpm and an autorotational speed of 800 to 3000 rpm; S4: Start the vacuum system of the planetary centrifugal mixer and continue the mixing reaction for 2 to 6 minutes to obtain a highly active and high melting point isocyanate prepolymer; S5: adding a curing agent to the obtained special high-activity and high-melting-point isocyanate prepolymer, turning on the planetary centrifugal vacuum mixer again, vacuum mixing the mixture evenly, and then injecting the mixture into a mold for curing and molding to obtain the high-activity and high-melting-point isocyanate prepolymer product.

8. The method for producing high-activity and high-melting-point isocyanate prepolymer products in small batches according to claim 7, characterized in that: The added mass of the curing agent is 2-15% of the mass of the high-activity and high-melting-point isocyanate prepolymer.

9. The method for producing high-activity and high-melting-point isocyanate prepolymer products in small batches according to claim 7, characterized in that: The curing agent is at least one of amine, diol and triol chain extenders.

10. The method for producing high-activity and high-melting-point isocyanate prepolymer products in small batches according to claim 7, characterized in that: The curing agent is one or more of ethylene glycol, butanediol, hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, trimethylolpropane, di-o-chlorodiphenylmethane and dimethylthiotoluenediamine.

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