CN114591484B - Preparation method of non-foaming polyurethane elastomer with excellent mechanical properties - Google Patents

Abstract

The invention relates to a preparation method of a non-foaming polyurethane elastomer with excellent mechanical properties, belonging to the technical field of polyurethane elastomers. Mix 70-71 parts of PTMEG2000, 19-20 parts of 330N, 7.3-7.5 parts of BDO, 1.8-2.0 parts of X-313 and 0.0003-0.002 parts of T-12 to make component A; The prepolymer with an NCO content between 12% and 13% formed by the reaction with PTMEG2000 is recorded as component B; component A and component B which are preheated to (30±2)°C at a speed of 1900rpm～2200rpm Stir and mix for (25±5)s, then put it under the condition of vacuum degree ≤0.09MPa for vacuum defoaming for 8min~10min, then put it into a mold preheated to (75±5)℃, and then put it in (75±5)℃ 5) Curing in an oven at ℃ for 1h to 1.5h, and then curing at (25±5)℃ for (48±5)h to obtain a non-foaming polyurethane elastomer with excellent mechanical properties.

Description

A kind of preparation method of non-foaming polyurethane elastomer with excellent mechanical properties

technical field

The invention relates to a preparation method of a non-foaming polyurethane elastomer with excellent mechanical properties, belonging to the technical field of polyurethane elastomers.

Background technique

Polyurethane elastomer is a widely used elastomer material. Because of its wide selectivity of raw materials and special microphase separation structure, it has excellent mechanical strength, toughness, wear resistance, oil resistance, etc., and can be applied to shoe materials. , pipes, films and sheets, cables, automobiles, construction, medicine and health, national defense and many other fields.

In the preparation process of polyurethane elastomer, foamed polyurethane elastomer can be obtained by adding foaming agent such as water. There are a large number of cell structures in the product, so the mechanical properties are relatively poor, and it is mainly used for vibration reduction, noise reduction, and heat preservation. Heat insulation, etc.; if no foaming agent is added, a non-foaming polyurethane elastomer will be obtained. Because there are no cells and a compact structure, it has excellent mechanical properties and is mainly used in automotive parts, pipes, construction and other fields. However, defects such as bubbles will inevitably be introduced during the preparation of non-foamed polyurethane elastomers, and due to the fast gelation speed, there is not enough time for defoaming before curing, so the theoretical mechanical properties cannot be achieved.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a method for preparing a non-foaming polyurethane elastomer with excellent mechanical properties. By regulating the content of each component, especially strictly controlling the content of the catalyst, the vacuum defoaming process is optimized at the same time. Process conditions, to control the degree of gelation reaction, so that there is enough time for defoaming treatment before molding, so as to effectively remove the air bubbles introduced during the preparation process, and further improve the elasticity of non-foaming polyurethane without affecting other properties body strength and toughness.

The purpose of the present invention is achieved through the following technical solutions.

A preparation method of a non-foaming polyurethane elastomer with excellent mechanical properties, said method comprising the following steps:

Stir and mix the components A and B preheated to (30±2)°C at a speed of 1900rpm~2200rpm for (25±5)s, and then vacuum defoaming for 8min~ 10min, then put it into a mold preheated to (75±5)℃, and then put it into a (75±5)℃ oven to cure for 1h~1.5h, and then cure it at (25±5)℃ (48±5) ) h to obtain a non-foaming polyurethane elastomer with excellent mechanical properties.

The A component is composed of polytetrahydrofuran ether diol (PTMEG2000) with a molecular weight of 2000, polyoxypropylene triol (330N) with a molecular weight of 4950, 1,4-butanediol (BDO), and the model number of Guangzhou Detian New Material Co., Ltd. It is prepared by mixing X-313 defoamer and dibutyltin dilaurate (T-12); among them, the mass parts of each component in component A are as follows: PTMEG200070-71 parts, 330N 19-20 parts, BDO 7.3~7.5 parts, X-313 1.8~2.0 parts and T-12 0.0003~0.002 parts;

The B component is a prepolymer with an NCO content between 12% and 13% formed by the reaction of isocyanate containing -NCO groups and PTMEG2000;

In addition, the molar ratio of -OH groups in component A to -NCO groups in component B is (1.03-1.07): 1; the water content of PTMEG2000, 330N and BDO are all less than or equal to 500ppm.

Further, the B component is a prepolymer with NCO content between 12% and 13% formed by reacting isocyanate containing -NCO group and PTMEG2000 at (80-85)°C for (3.8-4.2) h. body.

Further, the isocyanate containing -NCO group is 4,4'-diphenylmethane diisocyanate (MDI); at this time, the mass parts of each component in component B are as follows: PTMEG2000 54~57 parts and MDI 44~ 47 servings.

Further, first dissolve T-12 into 330N, and then mix with PTMEG2000, BDO and X-313.

Further, the mass fraction of T-12 in component A is 0.0003-0.0005.

Beneficial effect:

(1) The present invention controls the gelation reaction rate of the system by regulating and controlling the content of each component, especially the content of the catalyst, optimizes the process parameters in the preparation process at the same time, avoids introducing bubbles in the preparation process as much as possible, and has enough Time to carry out defoaming treatment before molding to remove the introduced air bubbles and reduce product defects, so as to obtain polyurethane elastomers with almost no cells, high strength and good toughness.

(2) Since the content of the catalyst has a great influence on the rate of gelation of the reaction system, the present invention reduces the content of the catalyst as much as possible, and the catalyst content is too low to be easy to accurately control, so the present invention first adds the catalyst with a low content and does not The high content of the reaction is diluted in 330N, and then the 330N containing the catalyst is mixed with PTMEG2000, BDO and X-313, so as to realize the precise control of the low content of the catalyst, and the operation is simple.

(3) The method of the present invention is simple to operate, effectively reduces the cell defects in the non-foaming polyurethane elastomer, makes the tensile strength of the prepared polyurethane elastomer ≥ 18MPa and elongation at break > 700%, which has a good application prospects.

Description of drawings

Fig. 1 is the scanning electron microscope (SEM) picture of the tensile section of the non-foaming polyurethane elastomer prepared in Example 1.

FIG. 2 is a surface scanning electron microscope image of the non-foaming polyurethane elastomer prepared in Comparative Example 1.

FIG. 3 is a scanning electron microscope image of the surface of the non-foaming polyurethane elastomer prepared in Comparative Example 2.

Detailed ways

The present invention will be further elaborated below in conjunction with specific embodiments, wherein the methods are conventional methods unless otherwise specified, and the raw materials can be obtained from open commercial channels unless otherwise specified.

Example 1

(1) Use water pump and oil pump to vacuum dehydrate PTMEG2000, 330N and BDO until the water content is less than or equal to 500ppm;

(2) Dissolve 0.005 parts of T-12 into 250 parts of dehydrated 330N for dilution and mix uniformly to obtain 330N containing T-12; 70.9 parts of dehydrated PTMEG2000, 19.7 parts of 330N containing T-12, 7.4 parts of dehydrated BDO and 1.9 parts of X-313 (the defoamer of X-313 of Guangzhou Detian New Material Co., Ltd.) were mixed uniformly to obtain component A;

Mix 45 parts of MDI and 55 parts of PTMEG uniformly under a nitrogen protective atmosphere, and stir and react at 80°C to 85°C for 4 hours to obtain a prepolymer terminated with -NCO, which is abbreviated as component B and its NCO content is 12.5 %;

(3) Preheat component A and component B to 30°C respectively, and then mix the preheated component A and Mix component B (that is, mix 53.4 parts of component A with 46.6 parts of component B), stir and mix at a speed of 2000rpm for 30s, and then vacuum defoam for 10min under the condition of vacuum degree ≤ 0.09MPa, and then put it into the pre- Heat it into a mold at 70°C, put it in an oven at 70°C for 1.5 hours, and then cure it at 25°C for 48 hours to obtain a non-foaming polyurethane elastomer with excellent mechanical properties.

The microscopic morphology of the prepared non-foaming polyurethane elastomer was characterized. From the SEM picture in Figure 1, it can be seen that the tensile section of the polyurethane elastomer has no obvious bubbles, indicating that the defoaming is complete during the preparation process. The tensile strength and elongation at break of the prepared non-foaming polyurethane elastomer were tested with reference to the standard GB/T1040.3-2006, and the tensile strength and elongation at break of the polyurethane elastomer were measured to be 19.18MPa and elongation at break 782%.

Example 2

(1) Use water pump and oil pump to vacuum dehydrate PTMEG2000, 330N and BDO until the water content is less than or equal to 500ppm;

(2) Dissolve 0.0045 parts of T-12 into 250 parts of dehydrated 330N for dilution and mix uniformly to obtain 330N containing T-12; 70.8 parts of dehydrated PTMEG2000, 19.5 parts of 330N containing T-12, 7.5 parts of dehydrated BDO and 1.8 parts of X-313 (the defoamer of X-313 of Guangzhou Detian New Material Co., Ltd.) were mixed uniformly to obtain component A;

Mix 44 parts of MDI and 56 parts of PTMEG uniformly under a nitrogen protective atmosphere, and stir and react at 80°C to 85°C for 4.2h to obtain a prepolymer terminated with -NCO, which is abbreviated as component B and its NCO content is 12.6%;

(3) Preheat component A and component B to 28°C respectively, and then mix the preheated component A and Mix component B (that is, mix 53 parts of component A with 47 parts of component B), stir and mix at a speed of 2200rpm for 30s, and then vacuum degassing for 8min under the condition of vacuum degree ≤ 0.09MPa, and then put it into the pre- Heat it into a mold at 75°C, put it in an oven at 75°C for 1 hour, and then cure it at 28°C for 50 hours to obtain a non-foaming polyurethane elastomer with excellent mechanical properties.

The microscopic morphology of the prepared non-foaming polyurethane elastomer was characterized, and it can be observed that there is no obvious cell defect in the prepared polyurethane elastomer, indicating that the degassing is complete during the preparation process. The tensile strength and elongation at break of the prepared non-foamed polyurethane elastomer were tested with reference to the standard GB/T1040.3-2006, and the tensile strength and elongation at break of the polyurethane elastomer were measured to be 18.68MPa and elongation at break 745%.

Comparative example 1

(1) Use water pump and oil pump to vacuum dehydrate PTMEG2000, 330N and BDO until the water content is less than or equal to 500ppm;

(2) 70.9 parts of dehydrated PTMEG2000, 19.7 parts of 330N, 0.1 part of T-12, 7.4 parts of dehydrated BDO and 1.9 parts of X-313 (Guangzhou Detian New Material Co., Ltd. model X-313 defoamer) Mix evenly to obtain component A;

Mix 45 parts of MDI and 55 parts of PTMEG uniformly under a nitrogen protective atmosphere, and stir and react at 80°C to 85°C for 4 hours to obtain a prepolymer terminated with -NCO, which is abbreviated as component B and its NCO content is 12.9 %;

(3) Preheat component A and component B to 30°C respectively, and then mix the preheated component A and Mix component B (that is, mix 53.7 parts of component A with 46.3 parts of component B), stir and mix at a speed of 2000rpm for 30s, and then vacuum defoam for 10min under the condition of vacuum degree ≤ 0.09MPa, and then put it into the pre- Heat it into a mold at 70°C, put it into an oven at 70°C to cure for 1.5 hours, and then cure it at 25°C for 48 hours to obtain a non-foaming polyurethane elastomer.

The microscopic morphology of the prepared non-foaming polyurethane elastomer was characterized. It can be seen from the SEM picture in Figure 2 that there are obvious cells in the polyurethane elastomer, indicating that the defoaming was not complete during the preparation process. The tensile strength and elongation at break of the prepared non-foaming polyurethane elastomer were tested with reference to the standard GB/T1040.3-2006, and the tensile strength and elongation at break of the polyurethane elastomer were measured to be 11.76MPa and elongation at break 484%.

Comparative example 2

(1) Use water pump and oil pump to vacuum dehydrate PTMEG2000, 330N and BDO until the water content is less than or equal to 500ppm;

(2) Dissolve 0.02 parts of T-12 into 250 parts of dehydrated 330N for dilution and mix uniformly to obtain 330N containing T-12; 70.9 parts of dehydrated PTMEG2000, 19.7 parts of 330N containing T-12, 7.4 parts of dehydrated BDO and 1.9 parts of X-313 (the defoamer of X-313 of Guangzhou Detian New Material Co., Ltd.) were mixed uniformly to obtain component A;

Mix 45 parts of MDI and 55 parts of PTMEG uniformly under a nitrogen protective atmosphere, and stir and react at 80°C to 85°C for 4 hours to obtain a prepolymer terminated with -NCO, which is abbreviated as component B and its NCO content is 12.6%. ;

(3) Preheat component A and component B to 30°C respectively, and then mix the preheated component A and Mix component B (that is, mix 53 parts of component A with 47 parts of component B), stir and mix at a speed of 1700rpm for 16s, and then vacuum degassing for 7min under the condition of vacuum degree ≤ 0.09MPa, and then put it into the pre- Heat it into a mold at 65°C, put it into an oven at 70°C to cure for 1.5 hours, and then cure it at 18°C for 48 hours to obtain a non-foaming polyurethane elastomer.

The microscopic morphology of the prepared non-foaming polyurethane elastomer was characterized. From the SEM picture in Figure 3, it can be seen that there are obvious cells in the polyurethane elastomer, indicating that the defoaming was not complete during the preparation process. The tensile strength and elongation at break of the prepared non-foaming polyurethane elastomer were tested with reference to the standard GB/T1040.3-2006, and the tensile strength and elongation at break of the polyurethane elastomer were measured to be 15.25MPa and elongation at break 602%.

According to the mechanical properties of the polyurethane elastomers prepared in Examples 1-2 and Comparative Examples 1-2, the present invention can effectively remove the impurities introduced in the preparation process by degassing by adjusting and controlling the catalyst content and optimizing the process parameters of the preparation process. Bubbles reduce the cell defects in the product, thereby significantly improving the tensile strength and elongation at break of polyurethane elastomers.

To sum up, the above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. A preparation method of a non-foaming polyurethane elastomer with excellent mechanical properties is characterized in that: the method comprises the following steps:

stirring and mixing the component A and the component B preheated to (30+/-2) DEG C at the rotating speed of 1900 rpm~2200 rpm for (25+/-5) s, then placing the mixture in a vacuum condition with the vacuum degree less than or equal to 0.09MPa for vacuum defoaming for 8-10 min, placing the mixture in a mould preheated to (75+/-5) DEG C, then placing the mixture in a baking oven at (75+/-5) DEG C for curing for 1-1.5 h, and then curing the mixture at (25+/-5) DEG C for (48+/-5) h to obtain the non-foaming polyurethane elastomer with excellent mechanical properties;

the component A is prepared by mixing PTMEG2000, 330N, BDO, X-313 and T-12; wherein the component A comprises the following components in parts by mass: 70-71 parts of PTMEG2000, 19-20 parts of 330N, 7.3-7.5 parts of BDO, 1.8-2.0 parts of X-313 and 0.0003-0.0005 parts of T-12;

the component B is a prepolymer with NCO content of 12% -13% formed by the reaction of isocyanate containing-NCO groups and PTMEG 2000;

wherein the molar ratio of the-OH group in the component A to the-NCO group in the component B is (1.03-1.07): 1, a step of; the water content of PTMEG2000, 330N and BDO is less than or equal to 500ppm;

the tensile strength of the prepared non-foaming polyurethane elastomer is more than or equal to 18MPa, and the elongation at break is more than 700%.

2. The method for producing a non-foaming polyurethane elastomer excellent in mechanical properties according to claim 1, characterized in that: the component B is a prepolymer with NCO content of 12% -13% formed by stirring and reacting isocyanate containing-NCO groups with PTMEG2000 at the temperature of 80-85 ℃ for 3.8-4.2 h.

3. The method for producing a non-foaming polyurethane elastomer excellent in mechanical properties according to claim 1 or 2, characterized in that: the isocyanate containing-NCO groups is MDI.

4. The method for producing a non-foaming polyurethane elastomer excellent in mechanical properties according to claim 3, characterized in that: the component B comprises the following components in parts by mass: 54-57 parts of PTMEG2000 and 44-47 parts of MDI.

5. The method for producing a non-foaming polyurethane elastomer excellent in mechanical properties according to claim 1, characterized in that: t-12 was dissolved in 330N and then mixed with PTMEG2000, BDO and X-313.

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