Preparation method of anti-blocking agent and high-temperature-resistant SIS elastomer

Abstract

The invention relates to a preparation method of an anti-blocking agent and a high-temperature-resistant SIS elastomer. The anti-blocking agent comprises talcum powder and calcium stearate, the mass ratio of the talcum powder to the calcium stearate is (95-105): (4-6), and the preparation method of the SIS elastomer composition comprises the following steps: taking an SIS elastomer primary product, adding the anti-blocking agent to the SIS elastomer primary product so that the addition amounts of the talcum powder and the calcium stearate are 950-1050 ppm and 40-60 ppm respectively, and drying to obtain the high-temperature-resistant SIS elastomer composition. The anti-blocking agent can be applied to preparation of the high-temperature-resistant SIS elastomer composition, and the prepared SIS elastomer composition has good high-temperature aging resistance and is not prone to blocking in the transportation and storage process; the preparation method of the anti-blocking agent is simple in process, low in production cost, stable in product quality and beneficial to industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to an anti-caking agent and its application in the preparation of high-temperature resistant SIS elastomers, as well as a method for preparing a high-temperature resistant SIS elastomer. Background Art

[0002] Styrene-isoprene-styrene (SIS) is an important type of styrenic thermoplastic elastomer prepared from styrene and isoprene. SIS elastomers have good mechanical properties, cohesion, adhesion properties, and excellent compatibility, and have currently been widely used in fields such as hot melt pressure-sensitive adhesives, coatings, and plastic modification. However, in the prior art, the prepared SIS elastomers are prone to caking after being placed for a period of time, such as during transportation and storage, which causes inconvenience for downstream manufacturers to use, increases production cost, decreases efficiency, and affects product use; and the existing SIS elastomers are difficult to have both the characteristics of not being prone to caking and good high-temperature aging resistance, and it is difficult to meet the market needs. Therefore, it is of great significance to improve the prior art and provide an anti-caking agent and SIS elastomers so that the prepared SIS elastomers have good high-temperature aging performance and are not prone to caking during transportation and storage to meet the actual application requirements. Summary of the Invention

[0003] In order to solve the above deficiencies of the prior art, the purpose of the present invention is to provide an anti-caking agent, which can be applied to the preparation of SIS elastomer compositions, improve the high-temperature aging performance of SIS elastomers, and make the preparation of SIS elastomer compositions not prone to caking, which is beneficial to improving transportation convenience and extending storage time.

[0004] Another object of the present invention is to provide a method for preparing a high-temperature resistant SIS elastomer composition. By adding the above anti-caking agent to the SIS elastomer, the obtained SIS elastomer composition has good high-temperature aging performance and the product is not prone to caking during transportation and storage; the preparation method of the SIS elastomer composition has a simple process, low production cost, stable product quality, and is conducive to industrial production.

[0005] The object of the present invention is achieved by the following technical solutions: an anti-caking agent, comprising talcum powder and calcium stearate, and the mass ratio of the talcum powder to the calcium stearate is 100:4.5 - 5.5.

[0006] Further, the calcium stearate is calcium stearate emulsion, the concentration of calcium stearate in the calcium stearate emulsion is 4 - 6 wt%, and the mass ratio of the talcum powder to the calcium stearate in the calcium stearate emulsion is 100:4.5 - 5.5.

[0007] The present invention also provides the use of the anti-caking agent in the preparation of a high-temperature resistant SIS elastomer composition.

[0008] Another object of the present invention is to provide a method for preparing a high-temperature resistant SIS elastomer composition, the preparation method comprising the following steps: taking a preliminary SIS elastomer product, adding the above anti-caking agent, the addition amount of the anti-caking agent being 990-1110 ppm, the addition amounts of talcum powder and calcium stearate being 950-1050 ppm and 40-60 ppm respectively, and drying to obtain a high-temperature resistant SIS elastomer composition.

[0009] Further, the method for preparing the preliminary SIS elastomer product comprises the following steps:

[0010] (1) By weight, take 4500 parts of a solvent, add 14-17 parts of styrene and mix evenly, then add 1-3 parts of an initiator for reaction; after the reaction solution reaches the peak temperature, after 5-7 minutes, add 84-86 parts of isoprene for polymerization reaction, and control the temperature of the reaction solution with cooling water;

[0011] (2) After 5 minutes from the peak temperature in step (1), add 4-6 parts of a terminator BHT (2,6-di-tert-butyl-4-methylphenol) dropwise to the reaction solution obtained in step (1), control the BHT dropping time within 5 minutes, and after completely adding BHT, mix for another 5 minutes to obtain a mixture A;

[0012] (3) Add 9000-11000 ppm of an antioxidant to the mixture A, stir, and then remove the solvent through a devolatilizer and pelletize to obtain a preliminary SIS elastomer product.

[0013] In the method for preparing the preliminary SIS elastomer product of the present invention, the temperature of the reaction solution is monitored in a timely manner; first add styrene and an initiator for reaction, and the peak temperature appears 5-10 minutes after the start of the reaction, and the peak temperature is about 72-78 °C; after 5-7 minutes from reaching the peak temperature, add isoprene for reaction, and the reaction rate of this reaction is relatively fast, and it is necessary to cool the reaction solution by passing cooling water through the reaction vessel, control the temperature of the reaction solution, and the time to start passing cooling water and the time of passing cooling water can be controlled according to the actual temperature, and the peak temperature reached by the reaction solution is about 94-106 °C; use BHT (2,6-di-tert-butyl-4-methylphenol) as a terminator to terminate the reaction, stop adding BHT (2,6-di-tert-butyl-4-methylphenol) 4-6 minutes after the reaction solution reaches the peak temperature, and add an antioxidant to improve its antioxidant property to obtain a preliminary SIS elastomer product with excellent comprehensive performance.

[0014] Further, in the step (1), 4500 parts of a solvent is taken, 14 - 17 parts of styrene is added, and the mixture is kept warm for 4 - 10 min at a temperature of 48 - 55°C and a pressure not greater than 0.1 MPa; then 1 - 3 parts of an initiator is added.

[0015] Further, in the step (1), the solvent is at least one of cyclohexane and n - hexane.

[0016] Further, in the step (3), the solvent includes cyclohexane and n - hexane, and the mass ratio of cyclohexane to n - hexane is 6 - 8:2 - 4.

[0017] Further, in the step (1), the initiator is n - butyllithium.

[0018] The present invention adopts an anionic polymerization method, uses a mixed solution of cyclohexane and n - hexane as a solvent and n - butyllithium as a co - initiator. After the SIS completes the three - block polymerization, BHT (2,6 - di - tert - butyl - 4 - methylphenol) is added as a terminator. The initial product of the SIS elastomer obtained is a high - flow, high - block granular white elastomer, and the glue solution is a colorless and transparent glue solution, which has excellent melt processability and elasticity. The product has good fluidity, and has better viscosity and mechanical properties during use. It can be applied to adhesives, and can also be applied to fields such as coatings and plastic modified products, with a wide range of applications.

[0019] Further, in the step (3), the antioxidant is at least one of antioxidant BHT, antioxidant 1076 and antioxidant 168.

[0020] Further, in the step (3), the antioxidant consists of antioxidant BHT, antioxidant 1076 and antioxidant 168 in a mass ratio of 0.8 - 1.2:1.8 - 2.2:0.8 - 1.2.

[0021] The present invention also provides a heat - resistant SIS elastomer composition, which is prepared by the preparation method of the above - mentioned SIS elastomer composition.

[0022] The beneficial effects of the present invention are as follows: The present invention prepares an anti - caking agent by combining talcum powder and calcium stearate, and the anti - caking agent can be applied to the preparation of a heat - resistant SIS elastomer composition. The present invention also provides a preparation method of a heat - resistant SIS elastomer composition. By adding the above - mentioned anti - caking agent to the SIS elastomer, the obtained SIS elastomer composition has good heat - resistant aging performance, and the product is not easy to cake during transportation and storage; the preparation method of the anti - caking agent has a simple process, low production cost, stable product quality, and is conducive to industrial production. Description of the Drawings

[0023] Figure 1Product diagrams of the SIS elastomer compositions of Comparative Example 4, Example 1, Comparative Example 5, and Comparative Example 7 after being subjected to high-temperature aging treatment for 140 minutes respectively. Detailed implementation mode

[0024] For the convenience of understanding by those skilled in the art, the present invention will be further described below in conjunction with embodiments. The content mentioned in the implementation mode does not limit the present invention.

[0025] In a typical implementation mode of the present invention, an anti-caking agent includes talcum powder and calcium stearate, and the mass ratio of the talcum powder to the calcium stearate is 100:4.5 - 5.5.

[0026] Further, the calcium stearate is in the form of a calcium stearate emulsion, the concentration of calcium stearate in the calcium stearate emulsion is 4 - 6 wt%, and the mass ratio of the talcum powder to the calcium stearate in the calcium stearate emulsion is 100:4.5 - 5.5.

[0027] Further, the present invention also provides the application of the anti-caking agent in the preparation of a high-temperature resistant SIS elastomer composition.

[0028] Another object of the present invention is to provide a preparation method of a high-temperature resistant SIS elastomer composition. The preparation method includes the following steps: taking a primary SIS elastomer product, adding the above anti-caking agent, and the addition amounts of the talcum powder and the calcium stearate emulsion are 950 - 1050 ppm and 950 - 1050 ppm respectively. The concentration of calcium stearate in the calcium stearate emulsion is 4 - 6 wt%, and water is used as the dispersant. After drying, a high-temperature resistant SIS elastomer composition is obtained.

[0029] Further, the preparation method of the primary SIS elastomer product includes the following steps:

[0030] (1) By weight, take 4500 parts of a solvent, add 14 - 17 parts of styrene and mix evenly, then add 1 - 3 parts of an initiator for reaction; after 5 - 7 minutes after the reaction liquid reaches the peak temperature, add 84 - 86 parts of isoprene for polymerization reaction, and control the temperature of the reaction liquid with cooling water;

[0031] (2) 5 minutes after the peak temperature in step (1) has passed, add 4 - 6 parts of BHT (2,6-di-tert-butyl-4-methylphenol) dropwise to the reaction liquid obtained in step (1). The dropping time of BHT is controlled within 5 minutes. After BHT is completely added, mix for another 5 minutes to obtain mixture A;

[0032] (3) Add 9000 - 11000 ppm of an antioxidant to mixture A, stir for 4 - 8 minutes, then remove the solvent through a devolatilizer and pelletize to obtain the primary SIS elastomer product.

[0033] Further, in the step (1), 4500 parts of a solvent are taken, 14 - 17 parts of styrene are added, and the mixture is kept warm at a temperature of 48 - 55°C and a pressure not greater than 0.1 MPa for 4 - 10 min; then 1 - 3 parts of an initiator are added.

[0034] Further, in the step (1), the solvent includes cyclohexane and n - hexane, and the mass ratio of cyclohexane to n - hexane is 6 - 8:2 - 4. The water value in the solvent is less than 5 ppm.

[0035] Further, in the step (3), the antioxidant consists of antioxidant BHT, antioxidant 1076 and antioxidant 168 in a mass ratio of 0.8 - 1.2:1.8 - 2.2:0.8 - 1.2.

[0036] Example 1

[0037] In this example, an anti - caking agent includes talcum powder and calcium stearate. The calcium stearate is in the form of a calcium stearate emulsion, and the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant is water; the mass ratio of talcum powder to calcium stearate in the calcium stearate emulsion is 100:5.

[0038] In this example, a preparation method of a high - temperature - resistant SIS elastomer composition includes the following steps: taking an SIS elastomer primary product, adding 2000 ppm of the above anti - caking agent, wherein the addition amounts of talcum powder and calcium stearate emulsion are 1000 ppm and 1000 ppm respectively, the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, the dispersant is water, and after drying, a high - temperature - resistant SIS elastomer composition is obtained. The prepared SIS elastomer composition is packaged, and the packaging specification is 25 kg / bag.

[0039] Further, the preparation method of the SIS elastomer primary product includes the following steps:

[0040] (1) By weight, 4500 parts of a solvent are taken, 15 parts of styrene are added and mixed evenly, and then 2 parts of an initiator are added for reaction; 5 min after the reaction liquid reaches the peak temperature, 85 parts of isoprene are added for polymerization reaction, and the reaction liquid is temperature - controlled by using cooling water, the peak temperature ≤ 95°C, and the time for passing cooling water is 10 min;

[0041] (2) 5 min after the peak temperature in step (1) has passed, 6 parts of BHT (2,6 - di - tert - butyl - 4 - methylphenol) are dropped into the reaction liquid obtained in step (1), the dropping time of BHT is controlled within 5 min, and after BHT is completely added, it is mixed for another 5 min to obtain mixture A;

[0042] (3) Add 10000 ppm of antioxidant to mixture A, stir for 5 min, then remove the solvent and pelletize to obtain the crude SIS elastomer.

[0043] Further, in step (1), take 4500 parts of solvent, add 15 parts of styrene, keep warm for 5 min at a temperature of 50 °C and a pressure not greater than 0.1 MPa; then add 2 parts of initiator.

[0044] Further, in step (1), the solvent includes cyclohexane and n-hexane, and the mass ratio of cyclohexane to n-hexane is 7:3.

[0045] Further, in step (3), the antioxidant consists of antioxidant BHT, antioxidant 1076 and antioxidant 168 in a mass ratio of 1:2:1.

[0046] As measured according to GB / T528-2009, the tensile strength of the crude SIS elastomer is greater than 7.0 Mpa, and the elongation at break is greater than 1000%; as measured according to GB / T3682-20000, the melt index of the crude SIS elastomer is 12.0 ± 3.0 g / 10 min.

[0047] Example 2

[0048] In this example, an anti-caking agent includes talcum powder and calcium stearate. The calcium stearate uses a calcium stearate emulsion, and the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant is water; the mass ratio of talcum powder to calcium stearate in the calcium stearate emulsion is 100:4.5.

[0049] In this example, a preparation method of a high-temperature resistant SIS elastomer composition includes the following steps: take the crude SIS elastomer, add 1900 ppm of the above anti-caking agent, wherein the addition amounts of talcum powder and calcium stearate emulsion are 1000 ppm and 900 ppm respectively, the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant uses water, and after drying, a high-temperature resistant SIS elastomer composition is obtained. Package the prepared SIS elastomer composition, and the packaging specification is 25 kg / bag.

[0050] Further, the preparation method of the crude SIS elastomer includes the following steps:

[0051] (1) By weight, take 4500 parts of solvent, add 14 parts of styrene and mix evenly, then add 2 parts of initiator for reaction; 5 min after the reaction solution reaches the peak temperature, add 86 parts of isoprene for polymerization reaction, the reaction time is 1 min, and use cooling water to control the temperature of the reaction solution;

[0052] (2) Five minutes after the peak temperature in step (1), add 4 - 6 parts of BHT (2,6 - di - tert - butyl - 4 - methylphenol) dropwise to the reaction solution obtained in step (1). Control the BHT dropping time within 5 minutes. After completely adding BHT, mix for another 5 minutes to obtain mixture A;

[0053] (3) Add 9000 ppm of antioxidant to mixture A, stir, then remove the solvent and pelletize to obtain the initial product of SIS elastomer.

[0054] Furthermore, in step (1), take 4500 parts of solvent, add 14 parts of styrene, keep warm for 10 minutes at a temperature of 48 °C and a pressure not greater than 0.1 MPa; then add 1.5 parts of initiator.

[0055] Furthermore, in step (1), the solvent includes cyclohexane and n - hexane, and the mass ratio of cyclohexane to n - hexane is 6:4.

[0056] Furthermore, in step (3), the antioxidant consists of antioxidant BHT, antioxidant 1076 and antioxidant 168 in a mass ratio of 0.8:1.8:0.8.

[0057] The remaining content of this example is the same as that of Example 1 and will not be elaborated here.

[0058] Example 3

[0059] In this example, an anti - caking agent includes talcum powder and calcium stearate. The calcium stearate uses a calcium stearate emulsion, and the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant is water; the mass ratio of talcum powder to calcium stearate in the calcium stearate emulsion is 100:5.5.

[0060] In this example, a preparation method of a high - temperature - resistant SIS elastomer composition includes the following steps: Take the initial product of SIS elastomer, add 2100 ppm of the above anti - caking agent, wherein the addition amounts of talcum powder and calcium stearate emulsion are 1000 ppm and 1100 ppm respectively. The concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant uses water. After drying, a high - temperature - resistant SIS elastomer composition is obtained. Package the prepared SIS elastomer composition, and the packaging specification is 25 kg / bag.

[0061] Furthermore, the preparation method of the initial product of SIS elastomer includes the following steps:

[0062] (1) Take 4500 parts of solvent by weight, add 17 parts of styrene and mix evenly, then add 3 parts of initiator for reaction; after the reaction solution reaches the peak temperature, add 85 parts of isoprene after 5 minutes and carry out a polymerization reaction. The reaction time is 1 minute, and the reaction solution is temperature-controlled with cooling water.

[0063] (2) After 5 minutes after the peak temperature in step (1), add 6 parts of BHT ( 2,6- 2,6 - di - tert - butyl - 4 - methylphenol) dropwise to the reaction solution obtained in step (1). The dropping time of BHT is controlled within 5 minutes. After BHT is completely added, mix for another 5 minutes to obtain mixture A.

[0064] (3) Add 11000 ppm of antioxidant to mixture A, stir, then remove the solvent and pelletize to obtain the initial product of SIS elastomer.

[0065] Furthermore, in step (1), take 4500 parts of solvent, add 17 parts of styrene, and keep warm at a temperature of 55 °C and a pressure not greater than 0.1 MPa for 10 minutes; then add 3 parts of initiator.

[0066] Furthermore, in step (1), the solvent includes cyclohexane and n - hexane, and the mass ratio of cyclohexane to n - hexane is 8:2.

[0067] Furthermore, in step (3), the antioxidant consists of antioxidant BHT, antioxidant 1076, and antioxidant 168 in a mass ratio of 1.2:2.2:1.2.

[0068] The remaining content of this example is the same as that of Example 1 and will not be elaborated here.

[0069] Example 4

[0070] In this example, an anti - caking agent includes talcum powder and calcium stearate. The calcium stearate uses a calcium stearate emulsion. The concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant is water; the mass ratio of talcum powder to calcium stearate in the calcium stearate emulsion is 105:4.

[0071] In this example, a preparation method of a high - temperature - resistant SIS elastomer composition includes the following steps: Take the initial product of SIS elastomer, add 1850 ppm of the above anti - caking agent, wherein the addition amounts of talcum powder and calcium stearate emulsion are 1050 ppm and 800 ppm respectively. The concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant uses water. After drying, a high - temperature - resistant SIS elastomer composition is obtained.

[0072] The remaining content of this example is the same as that of Example 1 and will not be elaborated here.

[0073] Example 5

[0074] In this example, an anti-caking agent includes talcum powder and calcium stearate. The calcium stearate is in the form of a calcium stearate emulsion, and the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, with the dispersant being water. The mass ratio of talc to calcium stearate in the calcium stearate emulsion is 95:6.

[0075] In this example, a preparation method of a high-temperature resistant SIS elastomer composition includes the following steps: taking the initial product of SIS elastomer, adding 2150 ppm of the above anti-caking agent, where the addition amounts of talcum powder and calcium stearate emulsion are 950 ppm and 1200 ppm respectively, the concentration of calcium stearate in the calcium stearate emulsion is 5 wt%, and the dispersant is water. After drying, a high-temperature resistant SIS elastomer composition is obtained.

[0076] The remaining content of this example is the same as that of Example 1 and will not be elaborated here.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that in the preparation method of the SIS elastomer composition, the anti-caking agent used is talcum powder, and the addition amount of the anti-caking agent is 1500 ppm.

[0079] Comparative Example 2

[0080] The difference between this comparative example and Example 1 is that in the preparation method of the SIS elastomer composition, the anti-caking agent used is EBS, and the addition amount of the anti-caking agent is 1500 ppm.

[0081] Comparative Example 3

[0082] The difference between this comparative example and Example 1 is that in the preparation method of the SIS elastomer composition, the anti-caking agent used is zinc stearate, and the addition amount of the anti-caking agent is 1500 ppm.

[0083] Comparative Example 4

[0084] The difference between this comparative example and Example 1 is that in the preparation method of the SIS elastomer composition, the anti-caking agent used is the anti-caking agent of Example 1, and the addition amount of the anti-caking agent is 1500 ppm.

[0085] Comparative Example 5

[0086] The difference between this comparative example and Example 1 is that in the preparation method of the SIS elastomer composition, the anti-caking agent used is the anti-caking agent of Example 1, and the addition amount of the anti-caking agent is 2500 ppm.

[0087] Comparative Example 6

[0088] The difference between this comparative example and Example 1 is as follows: An anti-caking agent includes talcum powder and EBS emulsion. The concentration of EBS in the EBS emulsion is 5 wt%, and the dispersant is water; the mass ratio of the talcum powder to EBS in the EBS emulsion is 100:5.

[0089] In the preparation method of the SIS elastomer composition, the addition amount of the anti-caking agent is 1500 ppm, that is, the addition amounts of both the talcum powder and the EBS emulsion are 750 ppm.

[0090] Comparative Example 7

[0091] The difference between this comparative example and Example 1 is as follows: In the preparation method of the SIS elastomer composition, the anti-caking agent used is calcium stearate, and the addition amount of the anti-caking agent is 1500 ppm.

[0092] The SIS elastomer compositions prepared in Example 1 and Comparative Examples 1-7 were measured. The compositions and addition amounts of the anti-caking agents in each example are shown in Table 1 below:

[0093] Table 1:

[0094]

[0095] Among them, the substances constituting the anti-caking agent are respectively represented as follows: talcum powder is denoted as A, EBS is denoted as B, zinc stearate is denoted as C, calcium stearate is denoted as D, calcium stearate emulsion (concentration 5 wt%) is denoted as D-1, and EBS emulsion (concentration 5 wt%) is denoted as B-1.

[0096] The experimental methods and experimental result data were measured as follows:

[0097] (1) Take the initial SIS elastomer product, add the anti-caking agent amounts in Table 1 respectively to obtain various SIS elastomer compositions, and conduct packaging. The packaging specification is 25 kg / bag; take 100 g of each sample and put it into a 300 mL beaker for standby. Since the product needs to be transported on the road or by sea after production and packaging, usually each pallet loads one ton, that is, 40 bags / pallet, and two pallets are stacked together, that is, each batch of materials needs to bear 15 times the weight, about 1.5 kg. Now take 100 g of each sample and put it into a 300 mL beaker, add a 1.5 kg weight, and place it in the experiment. The temperature in the laboratory is controlled at 35°C ± 5°C, and the humidity is 50 ± 10%. Observe the samples every week and gently touch the beaker to see if the samples are loose. The experimental results are shown in Table 2 below:

[0098] Table 2:

[0099]

[0100] Experimental results: 1500ppm was added to Comparative Examples 1 and 2. The samples loosened in the first week. In the second and third weeks, the samples gradually became sticky and agglomerated slightly. Until the fifth week, the samples were completely adhered and completely agglomerated. This proves that the anti-caking agent added to the initial SIS elastomer in Comparative Examples 1 and 2 can easily cause the samples to agglomerate during shipping or transportation, which leads to inconvenience for downstream manufacturers, increased production costs, decreased efficiency, and serious fluctuations in product performance. Other anti-caking agents produce similar phenomena. In Example 1, the amount of anti-caking agent added was 2000ppm, and the product met all transportation requirements; in Comparative Example 5, the amount of anti-caking agent added was 2500ppm, and the product could also meet the anti-caking requirements, but the product cost increased. In addition to the requirements of looseness and non-caking during transportation, the product still requires aging resistance in a high-temperature oven and whether the adhesive is transparent during use. Comparative Example 5 added 2500ppm of the anti-caking agent in Example 1, but none of them met the requirements.

[0101] (ii) Take the initial SIS elastomer, take 5g of each sample and add the anti-caking dosage in Table 1 and spread it on an aluminum platinum plate (specifications: top diameter 100mm, bottom diameter 92mm, height 8mm) for later use. Oven: Electric constant temperature blast drying oven. Temperature 165℃±3℃. After the oven temperature reaches 165℃, keep the temperature constant for 30 minutes, then put the spare samples into the oven together, and observe the color changes of the samples at different times. The high temperature aging resistance time and color changes of the anti-caking agent are shown in Table 3 below.

[0102] Table 3:

[0103]

[0104] Experimental results: The amount of anti-caking agent added in Comparative Examples 1 and 2 was 1500ppm. The color of the samples changed from light yellow to yellow at 110min; the sample of Comparative Example 2 turned completely yellow at 120min, and Comparative Example 1 also turned completely yellow after 10min. The color of other samples also slowly changed from light yellow to yellow over time. However, 1500ppm of anti-caking agent was added to Comparative Example 4, and the color of the sample at 180min was the same as the initial experimental color, without any change; 2000ppm of anti-caking agent was added to Example 1, and the sample was only slightly light yellow, close to white, which met the experimental index range. 2500ppm of anti-caking agent was added to Comparative Example 5, and the sample turned yellow at 160min.

[0105] The products of Comparative Example 4, Example 1, Comparative Example 5 and Comparative Example 7 after high temperature treatment for 140 minutes are shown in FIG. Figure 1 As shown, it can be seen that the products of Comparative Example 4 and Example 1 are white, the product of Comparative Example 5 is light yellow, and the product of Comparative Example 7 is yellow. Figure 1It can be seen that when the anti-caking agents of Comparative Examples 1-3 and Comparative Examples 5-7 are added, the high-temperature aging effect of the SIS elastomer composition is poor and it is easy to turn yellow; while when the anti-caking agent of the present invention is added, at the same addition amount, the SIS elastomer composition has better high-temperature aging resistance, but when the addition amount of the anti-caking agent of the present invention is too much, it will easily have an adverse effect on the high-temperature aging effect of the SIS elastomer composition. Therefore, in Example 1, by designing the composition and addition amount of the anti-caking agent, the SIS elastomer composition has the advantages of being not easy to cake and having good high-temperature aging resistance.

[0106] From the experiments on the caking evaluation time of the anti-caking agent, the high-temperature aging resistance of the anti-caking agent, and the transparency of the anti-caking agent added to the adhesive by adding different anti-caking agents to the initial SIS elastomer product, it can be seen that the specific composition of the anti-caking agent and the set addition amount of the anti-caking agent used in Example 1 can meet all conditions. Not only does the sample not cake during transportation or storage, but it also does not affect the high-temperature aging resistance of the product, and it is transparent when used by downstream manufacturers in the adhesive. Therefore, the SIS elastomer composition prepared in the examples of the present invention has good high-temperature aging resistance and is not easy to cake. When it is applied to the above-mentioned adhesive, the adhesive is transparent, meeting the actual application requirements.

[0107] The above specific embodiments further illustrate the technical solutions and beneficial effects of the present invention, rather than limiting the implementation manners. For those skilled in the art, any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. An anti-caking agent, characterized in that: It includes talcum powder and calcium stearate, and the mass ratio of the talcum powder to the calcium stearate is 95 - 105:4 - 6.

2. The anti-caking agent according to claim 1, wherein: The calcium stearate adopts a calcium stearate emulsion, the concentration of calcium stearate in the calcium stearate emulsion is 4 - 6 wt%, and the mass ratio of the talcum powder to the calcium stearate in the calcium stearate emulsion is 95 - 105:4 - 6.

3. Application of the anti-caking agent according to any one of claims 1 - 2 in preparing a high-temperature resistant SIS elastomer composition.

4. A method for preparing a high-temperature resistant SIS elastomer composition, characterized in that: It includes the following steps: Take the initial SIS elastomer product, add the anti-caking agent according to any one of claims 1 - 2, so that the addition amounts of the talcum powder and the calcium stearate are 950 - 1050 ppm and 40 - 60 ppm respectively, dry it to obtain a high-temperature resistant SIS elastomer composition.

5. The preparation method of the SIS elastomer composition according to claim 4, wherein: The preparation method of the initial SIS elastomer product includes the following steps: (1) By weight, take 4500 parts of a solvent, add 14 - 17 parts of styrene and mix evenly, then add 1 - 3 parts of an initiator for reaction; 5 - 7 minutes after the reaction solution reaches the peak temperature, add 84 - 86 parts of isoprene for polymerization reaction, and control the temperature of the reaction solution with cooling water. (2) Drop 4 - 6 parts of the terminator 2,6 - di-tert-butyl-4-methylphenol into the reaction solution obtained in step (1), and stop adding 2,6 - di-tert-butyl-4-methylphenol 4 - 6 minutes after the reaction solution reaches the peak temperature to obtain mixture A. (3) Add 8000 - 15000 ppm of an antioxidant to mixture A, stir, then remove the solvent and pelletize to obtain the initial SIS elastomer product.

6. The anti-caking agent according to claim 4, characterized in that: In step (1), the solvent is at least one of cyclohexane and n-hexane.

7. The anti-caking agent according to claim 1, characterized in that: In step (1), the initiator is n-butyllithium.

8. The anti-caking agent according to claim 1, wherein: In step (3), the antioxidant is at least one of antioxidant BHT, antioxidant 1076 and antioxidant 168.

9. A heat-resistant SIS elastomer composition, characterized in that: Prepared by the preparation method according to any one of claims 4 - 9.

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