A method for small-batch production of highly reactive, high-melting-point isocyanate prepolymers and their products.

Abstract

This invention relates to a method for small-batch production of highly active, high-melting-point isocyanate prepolymers and their products, belonging to the field of chemical synthesis technology. The method for small-batch production of highly active, high-melting-point isocyanate prepolymers includes the following steps: S1: raw material pretreatment; S2: adding the pretreated raw materials to a planetary centrifugal mixer; S3: starting the planetary centrifugal mixer for mixing reaction; S4: activating the vacuum system of the planetary centrifugal mixer and continuing the mixing reaction to obtain the isocyanate prepolymer. This invention utilizes the strong shear mixing effect of the planetary centrifugal mixer to ensure rapid and uniform mixing of materials, and utilizes the vacuum system of the equipment to achieve degassing and rapid cooling, effectively controlling the mixing efficiency and reaction temperature during the prepolymer preparation process, ensuring no dead zones in the mixing, avoiding side reactions such as self-polymerization caused by excessive temperature, and ensuring the stability of the prepolymer molecular structure and the consistency of product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for small-batch production of high-activity high-melting-point isocyanate prepolymer and its products, belonging to the field of chemical synthesis. BACKGROUND

[0002] P-phenylene diisocyanate (PPDI), diphenyl methane diisocyanate (NDI) and dimethyl diphenyl diisocyanate (TODI) all belong to high-activity high-melting-point isocyanate. Taking NDI as an example, NDI prepolymer is an important intermediate of high polymer material, which is widely used in the fields of polyurethane elastomer, coating, adhesive, etc. In the process of small-batch production, there are many problems in the traditional prepolymer preparation method. On the one hand, it is difficult to control the temperature in the reaction process. The synthesis reaction of NDI prepolymer is an exothermic reaction. If the reaction temperature cannot be controlled effectively and timely, the temperature of the reaction system is easy to be too high, which can cause side reactions and affect the molecular structure and performance stability of the prepolymer. On the other hand, the mixing efficiency of the traditional mixing equipment is low, which makes it difficult to ensure the full and uniform mixing of the materials in the small-batch production, so that the quality of the prepolymer is uneven. In addition, after the preparation of NDI prepolymer in the traditional process, the prepolymer needs to be transferred to other equipment to add a curing agent for product preparation, which increases the production process and time cost, and impurities are easy to be introduced in the transfer process, which affects the quality of the product. Similarly, the production and processing of PPDI and TODI systems also have the same problems as NDI. In addition, the traditional prepolymer synthesis method also has the disadvantages of low heat transfer efficiency and slow cooling speed.

[0003] Therefore, it is urgent to develop a small-batch production method which can effectively control the reaction temperature, improve the mixing efficiency, and realize the integration of high-activity high-melting-point isocyanate prepolymer preparation and product preparation. SUMMARY

[0004] The present application relates to a method for small-batch production of high-activity high-melting-point isocyanate prepolymer and its products, belonging to the field of chemical synthesis.

[0005] The technical scheme provided by the present application is as follows:

[0006] One of the objects of the present application is to provide a method for small-batch production of high-activity high-melting-point isocyanate prepolymer, which comprises the following steps:

[0007] S1: dehydrate the polyol to a water content <0.05%, and crush the high-activity high-melting isocyanate monomer into small particles with a particle size <2mm;

[0008] S2: heat the dehydrated polyol to 80~140℃, then add it to a planetary centrifugal mixer, and then add the high-activity high-melting isocyanate monomer;

[0009] S3: start the planetary centrifugal mixer, and mix and react for 6~20 minutes at a revolution speed of 500~1500rpm and a rotation speed of 800~3000rpm;

[0010] S4: start the vacuum system of the planetary centrifugal mixer, and continue mixing and reacting for 2~6 minutes to obtain the high-activity high-melting isocyanate prepolymer.

[0011] On the basis of the above technical solution, the application can also be improved as follows:

[0012] Further, in step S2, the mass ratio of the polyol to the high-activity high-melting isocyanate monomer is 100:25~41.

[0013] Further, in step S4, the vacuum value of the vacuum system is -0.08~-0.1MPa.

[0014] Further, the high-activity high-melting isocyanate monomer is one or more of naphthalene diisocyanate (NDI), toluene diisocyanate (TODI), and p-phenylene diisocyanate (PPDI).

[0015] Further, the polyol is one or more of polybutanedioic polyol, adipic polyol, sebacic polyol, polycaprolactone polyol, polycarbonate polyol, polytetrahydrofuran polyol, and butadiene diol, and the hydroxyl value of the polyol is 28~224.4, and the molecular weight range is 500~4000.

[0016] The second object of the application is to provide a high-activity high-melting isocyanate prepolymer prepared by the method for small-batch production of the high-activity high-melting isocyanate prepolymer.

[0017] The third object of the application is to provide a method for small-batch production of a high-activity high-melting isocyanate prepolymer product, comprising the following steps:

[0018] S1: dehydrate the polyol to a water content <0.05%, and crush the high-activity high-melting isocyanate monomer into small particles with a particle size <2mm;

[0019] S2: the dehydrated polyol is heated to 80-140℃, added into a planetary centrifugal mixer, and then a high-activity high-melting-point isocyanate monomer is added;

[0020] S3: the planetary centrifugal mixer is started, and the mixing reaction is carried out at a revolution speed of 500-1500 rpm and a rotation speed of 800-3000 rpm for 6-20 minutes;

[0021] S4: the vacuum system of the planetary centrifugal mixer is started, and the mixing reaction is continuously carried out for 2-6 minutes to obtain a high-activity high-melting-point isocyanate prepolymer;

[0022] S5: a curing agent is added into the obtained special high-activity high-melting-point isocyanate prepolymer, the planetary centrifugal vacuum mixer is started again, and after uniform mixing under vacuum, the mixture is injected into a mold for curing and forming to obtain a high-activity high-melting-point isocyanate prepolymer product.

[0023] Further, the added mass of the curing agent is 2-15% of the mass of the high-activity high-melting-point isocyanate prepolymer.

[0024] Further, the curing agent is at least one of an amine, a diol, and a triol chain extender.

[0025] Further, the curing agent is one or more of ethylene glycol, butanediol, hydroquinone dihydroxyethyl ether (HQEE), resorcinol dihydroxyethyl ether (HER), trimethylolpropane, methylene dianiline (MOCA), and dimethylthio toluene diamine (E300).

[0026] Compared with the prior art, the technical solution provided by the application has the following beneficial effects:

[0027] 1. The planetary centrifugal mixer can realize rapid and sufficient mixing of materials in small-batch production under high-speed shearing, greatly improves the mixing efficiency, ensures the uniformity of the prepolymer, and improves the product quality.

[0028] 2. The planetary centrifugal mixer is used to realize rapid cooling through the vacuum system, can effectively control the reaction temperature during the preparation of the prepolymer, avoid side reactions such as self-polymerization caused by excessively high temperature, and ensure the stability of the prepolymer molecules.

[0029] 3. After the preparation of the high-activity high-melting-point isocyanate prepolymer is completed, the curing agent can be directly added in the same equipment for product preparation, realizing the integration of prepolymer preparation and product production, reducing the production process and material transfer process, reducing the production time cost and the risk of introducing impurities, and improving the production efficiency and product qualification rate. DETAILED DESCRIPTION

[0030] The principles and features of the present application are described below in conjunction with examples, which are only used to explain the present application and not intended to limit the scope of the present application. Example 1

[0031] A method for small-batch production of NDI prepolymer and its product, comprising the following steps:

[0032] S1: Dehydrate polytetrahydrofuran diol (hydroxyl value 112.2, molecular weight 1000) to a water content <0.05%, and crush NDI monomer into small particles with a particle size <2mm;

[0033] S2: Heat 1000g of dehydrated polytetrahydrofuran diol to 135℃, add it to a planetary centrifugal mixer, and then quickly add 407g of NDI monomer;

[0034] S3: Start the planetary centrifugal mixer and mix at a revolution speed of 1000rpm and a rotation speed of 900rpm for 6 minutes;

[0035] S4: Start the vacuum system of the planetary centrifugal mixer, vacuum to -0.1MPa, and continue centrifugal mixing for 6 minutes to obtain the NDI prepolymer;

[0036] S5: Add 75g of 1.4-butanediol to the NDI prepolymer, start the planetary centrifugal mixer again, mix uniformly, and then pour into a mold for solidification and molding to obtain the NDI prepolymer product. Example 2

[0037] A method for small-batch production of NDI prepolymer and its product, comprising the following steps:

[0038] S1: Dehydrate polycaprolactone diol (hydroxyl value 56.1, molecular weight 2000) to a water content <0.05%, and crush NDI monomer into small particles with a particle size <2mm;

[0039] S2: Heat 1000g of dehydrated polycaprolactone diol to 135℃, add it to a planetary centrifugal mixer, and then quickly add 258g of NDI monomer;

[0040] S3: Start the planetary centrifugal mixer and mix at a revolution speed of 1000rpm and a rotation speed of 1000rpm for 8 minutes;

[0041] S4: Start the vacuum system of the planetary centrifugal mixer, vacuum to -0.1MPa, and continue centrifugal mixing for 6 minutes to obtain the NDI prepolymer;

[0042] S5: 59 g of 1.4-butanediol is added to the NDI prepolymer, the planetary centrifugal mixer is started again, and after uniform mixing, the NDI prepolymer product is obtained by injection molding and curing. Example 3

[0043] A method for small-batch production of a PPDI prepolymer and a product thereof, comprising the following steps:

[0044] S1: The polytetrahydrofuran diol (hydroxyl value 112.2, molecular weight 1000) is dehydrated to a water content <0.05%, and the PPDI monomer is crushed into small particles with a particle size <2 mm;

[0045] S2: 1000 g of the dehydrated polytetrahydrofuran diol is heated to 80°C, and then added to the planetary centrifugal mixer, followed by the rapid addition of 315 g of PPDI monomer;

[0046] S3: The planetary centrifugal mixer is started, and the mixing reaction is carried out at a revolution speed of 1000 rpm and a rotation speed of 1000 rpm for 20 minutes;

[0047] S4: The vacuum system of the planetary centrifugal mixer is started, and vacuum is drawn to -0.08 MPa, and the centrifugal mixing is continued for 2 minutes to obtain the PPDI prepolymer;

[0048] S5: 162 g of HER is added to the PPDI prepolymer, the planetary centrifugal mixer is started again, and after uniform mixing, the NDI prepolymer product is obtained by injection molding and curing. Example 4

[0049] A method for small-batch production of a TODI prepolymer and a product thereof, comprising the following steps:

[0050] S1: The polycaprolactone diol (hydroxyl value 56.1, molecular weight 2000) is dehydrated to a water content <0.05%, and the TODI monomer is crushed into small particles with a particle size <2 mm;

[0051] S2: 1000 g of the dehydrated polycaprolactone diol is heated to 120°C, and then added to the planetary centrifugal mixer, followed by the rapid addition of 265 g of TODI monomer;

[0052] S3: The planetary centrifugal mixer is started, and the mixing reaction is carried out at a revolution speed of 1000 rpm and a rotation speed of 1000 rpm for 10 minutes;

[0053] S4: The vacuum system of the planetary centrifugal mixer is started, and vacuum is drawn to -0.09 MPa, and the centrifugal mixing is continued for 6 minutes to obtain the TODI prepolymer;

[0054] S5: 132g MOCA was added into the TODI prepolymer, the planetary centrifugal mixer was started again, after mixing evenly, it was injected into the mold for curing and molding, and the TODI prepolymer product was obtained.

[0055] Comparative Example 1:

[0056] A method for small-batch production of NDI prepolymer and its product, comprising the following steps:

[0057] S1: The polytetrahydrofuran diol (hydroxyl value 112.2, molecular weight 1000) was dehydrated to a water content <0.05%, and the NDI monomer was crushed into small particles with a particle size <2mm;

[0058] S2: 1000g of the dehydrated polytetrahydrofuran diol was added into a 2000ml stainless steel cup and heated to 130℃, and then 407g of NDI was quickly added;

[0059] S3: High-speed stirring was performed for 15 minutes using a stirrer for mixing reaction;

[0060] S4: After standing and cooling to 85℃, the NDI prepolymer was obtained;

[0061] S5: 75g of 1.4-butanediol was added into the NDI prepolymer, and after rapid stirring and defoaming, it was poured into a mold to obtain the NDI prepolymer product.

[0062] Comparative Example 2

[0063] A method for small-batch production of NDI prepolymer and its product, comprising the following steps:

[0064] S1: The polytetrahydrofuran diol (hydroxyl value 112.2, molecular weight 1000) was dehydrated to a water content <0.05%, and the NDI monomer was crushed into small particles with a particle size <2mm;

[0065] S2: 1000g of the dehydrated polytetrahydrofuran diol was heated to 135℃ and added into a planetary centrifugal mixer, and then 407g of NDI monomer was quickly added;

[0066] S3: The planetary centrifugal mixer was started, and the mixing reaction was carried out at a revolution speed of 400rpm and a rotation speed of 600rpm, after 8 minutes of reaction, the vacuum system of the planetary centrifugal mixer was started, and vacuum was drawn to -0.1MPa, and the vacuum centrifugal mixing was continued for 3 minutes;

[0067] S4: The vacuum system of the planetary centrifugal mixer was started, and vacuum was drawn to -0.1MPa, and the centrifugal mixing was continued for 6 minutes, and the NDI prepolymer was obtained;

[0068] S5: 75g 1.4-butanediol is added into the NDI prepolymer, the planetary centrifugal mixer is started again, after uniform mixing, the NDI prepolymer is injected into a mold for curing and forming, and the NDI prepolymer product is obtained.

[0069] Comparative Example 3

[0070] A method for small-batch production of a PPDI prepolymer and a product thereof, comprising the following steps:

[0071] S1: polytetrahydrofuran diol (hydroxyl value 112.2, molecular weight 1000) is dehydrated to a water content <0.05%, and PPDI monomer is crushed into small particles with a particle size <2mm;

[0072] S2: 1000g of the dehydrated polytetrahydrofuran diol is heated to 80℃, and then added into a planetary centrifugal mixer, and 315g of PPDI monomer is quickly added;

[0073] S3: the planetary centrifugal mixer is started, and mixing reaction is carried out at a revolution speed of 300rpm and a rotation speed of 600rpm for 20 minutes;

[0074] S4: the vacuum system of the planetary centrifugal mixer is started, and vacuum is drawn to -0.1MPa, and centrifugal mixing is continued for 2 minutes, and the PPDI prepolymer is obtained;

[0075] S5: 162g of HER is added into the PPDI prepolymer, the planetary centrifugal mixer is started again, after uniform mixing, the NDI prepolymer is injected into a mold for curing and forming, and the NDI prepolymer product is obtained.

[0076] Performance test:

[0077] The prepolymer products obtained in Examples 1-4 and Comparative Examples 1-3 are subjected to performance test.

[0078] The results are shown in Table 1.

[0079] Table 1: Performance test data table

[0080]

[0081] As can be seen from Table 1, Examples 1-4 are superior to Comparative Examples 1-3 in hardness, tensile strength, tear strength, elongation, resilience and compression set, which indicates that the product obtained by the preparation method of the present application has better mechanical strength, elasticity and durability.

[0082] The above description is only the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for small batch production of high active high melting point isocyanate prepolymer characterized by, The method comprises the following steps: S1: dehydrate the polyol to a water content <0.05%, and crush the high-activity high-melting isocyanate monomer into small particles with a particle size <2mm; S2: heat the dehydrated polyol to 80-140℃, add it into a planetary centrifugal mixer, and then add the high-activity high-melting isocyanate monomer; the mass ratio of the polyol to the high-activity high-melting isocyanate monomer is 100:25-41; S3: start the planetary centrifugal mixer, mix and react for 6-20 minutes at a revolution speed of 500-1500rpm and a rotation speed of 800-3000rpm; S4: start the vacuum system of the planetary centrifugal mixer, the vacuum value of the vacuum system is -0.08 to -0.1MPa, and continue to mix and react for 2-6 minutes to obtain the high-activity high-melting isocyanate prepolymer; The high-activity high-melting isocyanate monomer is one or more of naphthalene diisocyanate, diphenyl diisocyanate and p-phenylene diisocyanate.

2. The process for small batch production of high active high melting point isocyanate prepolymer as claimed in claim 1 wherein, The polyol is one or more of polybutanedioic polyol, adipic polyol, sebacic polyol, polycaprolactone polyol, polycarbonate polyol and polytetrahydrofuran polyol, the hydroxyl value of the polyol is 28-224.4, and the molecular weight range is 500-4000.

3. A high activity, high melting point isocyanate prepolymer characterized by, The high-activity high-melting isocyanate prepolymer is prepared by the method of claim 1 or 2.

4. A process for producing a high activity high melting point prepolymer product from the isocyanate prepolymer of claim 3, characterized by, The method comprises the following steps: S1: dehydrate the polyol to a water content <0.05%, and crush the high-activity high-melting isocyanate monomer into small particles with a particle size <2mm; S2: heat the dehydrated polyol to 80-140℃, add it into a planetary centrifugal mixer, and then add the high-activity high-melting isocyanate monomer; S3: start the planetary centrifugal mixer, mix and react for 6-20 minutes at a revolution speed of 500-1500rpm and a rotation speed of 800-3000rpm; S4: start the vacuum system of the planetary centrifugal mixer, continue to mix and react for 2-6 minutes to obtain the high-activity high-melting isocyanate prepolymer; S5: add a curing agent to the obtained high-activity high-melting isocyanate prepolymer, start the planetary centrifugal vacuum mixer again, uniformly mix under vacuum, and then pour into a mold for curing and forming to obtain the high-activity high-melting isocyanate prepolymer product.

5. The process for small batch production of high active high melting point isocyanate prepolymer articles as claimed in claim 4 wherein, The added mass of the curing agent is 2-15% of the mass of the high-activity high-melting isocyanate prepolymer.

6. The process for small batch production of high active high melting point isocyanate prepolymer articles as claimed in claim 4 wherein, The curing agent is at least one of an amine, a diol and a triol chain extender.

7. The process for small batch production of high active high melting point isocyanate prepolymer articles as claimed in claim 4 wherein, The curing agent is one or more of ethylene glycol, butanediol, hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, trimethylolpropane, di-o-chloro-diphenylamine methane and dimethylthio-toluene diamine.

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