CN118459905A - A modified resin with anti-slip performance and its preparation method and application - Google Patents

Abstract

The present invention belongs to the technical field of rubber industry, and specifically discloses a modified resin with anti-slip performance, a preparation method and an application thereof, wherein the anti-slip performance modified resin is prepared by mixing the following components in weight percentage: 0%-30% of de-cyclized C5 petroleum resin, 15%-55% of thermally polymerized C9 petroleum resin, and 30%-70% of a-methylstyrene and styrene copolymer resin. The preparation process is as follows: (1) heating and melting a-methylstyrene and styrene copolymer resin; (2) adding de-cyclized C5 petroleum resin and thermally polymerized C9 petroleum resin to the above-mentioned molten resin, and controlling the temperature to react; (3) transferring the material, granulating, and packaging the modified resin product after the reaction is completed. The present invention utilizes the chain segment free radicals generated when the resin is depolymerized at high temperature to initiate polymerization, thereby obtaining a modified resin with a high Tg. The production process of the present invention is simple to operate, does not require a catalyst, and obtains a modified resin with controllable Tg; thereby improving the anti-slip performance of the rubber and improving the driving safety of the tire.

Description

A modified resin with anti-slip performance and its preparation method and application

Technical Field

The invention belongs to the technical field of rubber industry, relates to a modified resin in a rubber composition, and specifically relates to a modified resin with anti-slip performance, a preparation method and application thereof.

Background Art

As of the end of September 2023, the number of motor vehicles in China will reach 430 million, and the number of car drivers will reach more than 500 million. The driving safety of cars is highly valued, and tires, as an important part of cars and the only part of cars that touch the road, have a significant impact on the driving safety of cars. When cars are driving on wet roads in rainy days, due to the effect of water, the adhesion friction between the tread rubber and the ground is significantly reduced, and the wet grip of the tire will drop significantly, resulting in a longer braking distance. For passenger cars, due to their higher driving speeds, the anti-wet performance of tires is more important. Anti-wet performance is an important indicator to measure the driving safety of tires, especially the driving safety in rainy days. Therefore, improving the anti-wet performance of tires is particularly important for driving safety.

In order to solve the problem of how to improve the anti-skid performance of tires, increasing the glass transition temperature (Tg) of tires is a major means. As the Tg of the tire rubber composition increases, its loss factor in the low temperature zone becomes larger, which is beneficial to improving the anti-skid performance and traction of the tire. At present, the commonly used methods for improving the Tg value of tires can be divided into two categories. One is to improve the Tg of the tire from the perspective of formulation. For example, patent CN114163702A uses different formulations for the tread rubber of the groove bottom and the tread rubber of the ribs, which achieves a higher anti-skid performance while preventing the tire from cracking at low temperatures in winter. Although this method has excellent effects, it has strong limitations in formula adjustment and narrow applicability, and it is difficult to fundamentally improve the anti-skid performance of most tires.

Another type of modified resin can be added to the tire. The key point of using modified resin to improve the anti-skid performance of the tire lies in its good compatibility with rubber and the high glass transition temperature of the resin. Compatibility is the premise. Compatibility means that the resin has both aromatic structure and aliphatic hydrocarbon structure through modification. According to the principle of like dissolves like, the modified resin has good compatibility with rubber; the high Tg of the resin is the essence. The modified resin often has a higher Tg value relative to rubber. Therefore, the addition of modified resin can significantly increase the Tg value of the tire and thus improve the anti-skid performance of the tire. Patent CN109912806A introduces a modified resin. Its innovation is to introduce resins with different structures to improve the compatibility between the resin and rubber, thereby improving anti-skid performance. However, from the application results, the improvement of anti-skid performance is not obvious, and it is impossible to control the size of anti-skid performance by controlling the resin index in a targeted manner. The essential reason is that it is not understood that the core of anti-skid is the high Tg value of the resin, so it is impossible to control the size of the anti-skid performance of the rubber by the resin index.

Therefore, controlling the Tg value of the modified resin is the key to controlling the anti-slip performance of the rubber, but the existing methods for regulating the Tg of the resin are mostly polymerization and modification, which have the problems of complex process, long time consumption, high production cost and low production capacity. For example, patent CN1005260B introduces a method of controlling the ratio of different monomers of the copolymerized resin to achieve control of the Tg of the product. This method is achieved through cationic polymerization, which has high requirements for the polymerization system, anhydrous and oxygen-free, harsh production process, high production cost investment, and difficult control of structural index stability. At the same time, there are more three wastes in post-processing. Patent CN114702611A describes a modification method that preferentially reacts with oligomers to regulate the Tg of the resin, but this method requires controlling the catalyst dripping speed and polymerization temperature, and the resin structure is different, the catalyst dripping speed and temperature are different, the process is relatively complicated, the production control is difficult, and it is difficult to achieve industrialization.

In summary, based on the current substantial increase in demand for resins that improve tire anti-skid performance, it is very meaningful to invent a preparation method for increasing the Tg of a resin that has a simple production process, high production capacity, and a flexible and controllable structure.

Summary of the invention

In view of the deficiencies in the prior art, an object of the present invention is to provide a modified resin with anti-skid performance. The molecular weight of the modified resin of the present invention is significantly increased, the Tg is improved, and the anti-skid performance is excellent; the modified resin of the present invention is applied to a rubber composition to improve the driving safety of the tire; another object of the present invention is to provide a method for preparing a modified resin with a simple synthesis process, low cost, high production capacity, and the ability to control the Tg size.

The present invention is achieved through the following technical solutions:

A modified resin with anti-slip performance is prepared by mixing the following components in weight percentage: 0%-30% of de-annulated C5 petroleum resin, 15%-55% of thermally polymerized C9 petroleum resin, and 30%-70% of a-methylstyrene and styrene copolymer resin.

A further improvement of the present invention is:

The number average molecular weight (Mn) of the de-ringed C5 petroleum resin is 450-650.

Furthermore, the number average molecular weight of the thermally polymerized C9 petroleum resin is 400-600.

Furthermore, the number average molecular weight of the a-methylstyrene and styrene copolymer resin is 450-650, and the proportion of styrene in the copolymer resin is 20wt%-80wt%.

A further improvement of the present invention is:

A method for preparing a modified resin with anti-slip performance comprises the following steps:

(1) heating and melting a-methylstyrene and styrene copolymer resin;

(2) adding de-cyclized C5 petroleum resin and thermally polymerized C9 petroleum resin to the above molten resin and reacting under controlled temperature;

(3) After the reaction is completed, the modified resin product is obtained by transferring the material, granulating and packaging.

The reaction equation is as follows:

Furthermore, the heating and melting temperature is 200-250° C., and the time is 0.5-1.5 h.

Furthermore, the temperature of the temperature-controlled reaction is 200-250° C., and the time is 2-5 hours.

A further improvement of the present invention is:

Application of the above modified resin with anti-slip performance in the preparation of rubber composition.

The present invention first heats and melts alpha-methylstyrene and styrene copolymers. During the heating and melting process, the alpha-methylstyrene and styrene copolymers are depolymerized at high temperature to generate segment free radicals. The temperature needs to be controlled so that the resin generates a reverse reaction of the polymerization reaction at high temperature, that is, a depolymerization reaction to form segment free radicals. The essence of this step is that the temperature is high and exceeds the bond energy of the resin, resulting in resin chain breakage. In the alpha-methylstyrene and styrene copolymers, tertiary carbon free radicals are formed at the end of the segment after the chain break of the alpha-methylstyrene. The conjugation effect of the benzene ring and the hyperconjugation effect of the methyl group exist around the free radicals, so that the free radicals are highly stable and can exist for a long time, providing the possibility of initiating polymerization. Then, decyclized C5 petroleum resin and thermally polymerized C9 petroleum resin are added to the above molten resin, and the segment free radicals generated in the above step are used to spontaneously initiate the self-polymerization reaction of active double bonds in the decyclized C5 petroleum resin and the thermally polymerized C9 petroleum resin to form a copolymer with a larger molecular weight, thereby preparing a resin with a higher Tg.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The raw materials used in the present invention are simple and easy to obtain, and no solvent or catalyst is required during the reaction process. The reaction is spontaneously reacted by mixing at high temperature, the operation process is short, the organic matter is less volatile, the environmental pollution is small, the production cost is low, the time consumption is short, the production capacity is high, the reaction process is green and environmentally friendly, and it can better meet the current tire market demand for resin volume;

(2) α-methylstyrene and styrene copolymer resins generate tertiary carbon radicals at high temperatures. By controlling the monomer ratio of α-methylstyrene and styrene copolymer resins, the number of active chain radicals at high temperatures can be controlled, thereby controlling the molecular weight of the modified resin, thereby achieving control of the Tg value of the modified resin;

(3) There are many types of rubber used in tires, and the content of aromatic hydrocarbons and aliphatic hydrocarbons in each rubber structure is different. However, the amount of de-cyclized C5 petroleum resin and thermally polymerized C9 petroleum resin used in the modified resin of the present invention can be flexibly adjusted, so that the content of aromatic hydrocarbons and aliphatic hydrocarbons in the modified resin can be flexibly changed according to the rubber structure, thereby increasing the compatibility of the resin with various rubbers and having a wider applicability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a GPC graph of the resins of Comparative Examples 1-3 and Examples 1-3.

From the GPC test mechanism, it can be seen that the smaller the molecular weight of the polymer is, the more pore structures and cavities it will flow through on the gel chromatography column, making the polymer elution time longer. Therefore, the molecular weight of the polymer can be characterized according to the elution time of the polymer. From the data in Figure 1, it can be seen that the molecular weight is: Example 1> Example 3> Example 2> Comparative Example 1> Comparative Example 3> Comparative Example 2. The above data proves that the monomer ratio of a-methylstyrene and styrene copolymer resin and the amount of resin can be controlled to regulate the number of active chain free radicals generated at high temperature, thereby controlling the molecular weight of the modified resin.

DETAILED DESCRIPTION

The present invention is described in detail below in conjunction with specific embodiments.

The present invention adopts the following method to detect the softening point, glass transition temperature (Tg), and number average molecular weight (Mn) of the raw material and the modified resin.

Softening point test: According to GB/T 2294-Determination method of softening point of coking solid products, the softening point test is carried out using SYD-2806H fully automatic asphalt softening point tester;

Glass transition temperature test: According to GB/T 19466-Plastics Differential Scanning Calorimetry (DSC), the test is carried out using a differential scanning calorimeter;

Molecular weight test: According to GB/T 21863-Gel Permeation Chromatography (GPC), the test was carried out using a gel permeation chromatograph.

The test data for raw materials are shown in Table 1:

Table 1 Softening point, Tg and Mn test results of raw materials

Example 1

In a 500ml flask equipped with a stirring device and a thermometer, 210g of a-methylstyrene and styrene copolymer resin (styrene accounts for 20%) were first added in a ratio of 15%:15%:70% (C5:C9:AMS). After heating and melting at 200-250℃, 45g of C5 resin and 45g of C9 resin were added and stirring was started. The reaction temperature was controlled at 240℃. After stirring for 3h, a modified resin was obtained. The softening point was tested to be 104.6℃, Tg was 54.7℃, and Mn was 986.

Embodiment 2-6

The ratio of raw materials was changed, and the process steps in Example 1 were repeated. The specific data parameters are shown in Table 2:

Table 2 Raw material ratios of Examples 1-6 and softening point, Tg and Mn test results of the obtained modified resins

As can be seen from Example 1, Example 2 and Example 3, the Tg and Mn of the modified resin product obtained by the reaction all show obvious improvement, and its Tg and Mn increase with the amount of α-methylstyrene and styrene copolymer resin in the modified resin, present a gradient improvement trend, the reason is that the increase of α-methylstyrene and styrene copolymer resin content makes it increase the number of free radicals produced at high temperature, thereby improving the probability of segment free radicals initiating other resin polymerization. The above data can prove that the mixture has a clear spontaneous reaction at high temperature. The modified resin product with significantly improved Tg and Mn is obtained. In addition, as can be seen from Example 4 and Example 5, with the increase of the proportion of styrene in α-methylstyrene and styrene copolymer resin, the Tg and Mn of the resin also show a decline, the main reason is that the styrene content increases, the corresponding α-methylstyrene content decreases, the number and probability of high temperature generation of segment free radicals decrease, causing the probability of segment free radicals initiating C5 and C9 resin polymerization to decrease. Therefore, we can control the proportion of styrene monomer in a-methylstyrene and styrene copolymer resin and the amount of resin used, thereby controlling the number of active chain free radicals at high temperature and further controlling the molecular weight and Tg value of the modified resin.

Example 7: Preparation of rubber composition

In order to test the application performance of different modified petroleum resins prepared by the present invention, the resins of Comparative Examples 1-3 and the anti-slip modified resins prepared by Examples 1-3 and Example 6 were selected and added to rubber, and the specific formula is shown in Table 3. Rubber compositions A-G were prepared by mixing.

The rubber mixing process is as follows:

Step 1 (mixing): First, NS460 and RB9000 are mixed thinly on an open mill according to the mass ratio and mixed evenly. Then the combined rubber is added to the Haake torque rheometer, and the temperature is set to 110°C and the speed is 60rpm. After mixing for 30s, resin, zinc oxide, N-399, antioxidant RD, antioxidant 4020, SA and Si69 are added according to the mass ratio. After mixing for 120s, carbon black and white carbon black are added twice with an interval of 60s. After mixing for 240s, the first masterbatch is obtained by rubber removal, and the rubber shooting temperature is 135℃~145℃.

Use an open mixer to thinly pass a section of masterbatch 3 times, and let it stand for 2h~4h after unrolling.

(2) Step 2 (two-stage mixing): The obtained first-stage masterbatch, sulfur, accelerator CZ and accelerator DPG are added into the Haake torque rheometer according to the mass ratio, and the temperature is set at 90°C and the speed is 55 rpm. After mixing for 120 seconds, the rubber composition is discharged, and the discharge temperature is 95°C~105°C. The obtained rubber composition is then thin-passed on an open mill for 5 times, and after being removed from the sheet, it is left to stand for 6~8 hours before being vulcanized.

The rubber performance test method is as follows:

The commonly used characterization method for rubber anti-skid performance is dynamic thermal mechanical analysis (DMA), which is generally performed by using a dynamic mechanical analyzer to test the vulcanized rubber. In dynamic thermal mechanical analysis, the larger the 0℃ tanδ value, the better the anti-skid performance of the rubber; the smaller the 60℃ tanδ value, the lower the heat generation value of the rubber. The specific test results are shown in Table 4.

Table 3 Rubber composition formula

Table 4 Rubber composition performance test results

The following conclusions can be drawn from the data in the above table:

The resins used in the compositions A-G in the above table are respectively: de-annulated C5 resin, thermally polymerized C9 resin, a-methylstyrene and styrene copolymer resin, and synthesized modified anti-skid resin. It can be seen from the data in the table that the anti-skid performance of the composition is linearly correlated with the Tg of the composition, and the composition Tg is: D>G>F>E>C>B>A, and the anti-skid performance is also D>G>F>E>C>B>A; at the same time, when the compatibility of the resin and the rubber composition is equivalent, as the Tg of the modified resin increases, the Tg of the rubber material also shows an upward trend, and the anti-skid performance of the composition is better. Therefore, the preparation method provided by the present invention can achieve controllable Tg of the modified resin, and then can achieve regulation of the anti-skid performance of the composition.

From the above data, it can be seen that the modified anti-skid resin obtained in Example 1 has a significantly improved anti-skid performance compared with the resins of Comparative Examples 1, 2 and 3, with an improvement of 20%-30%, and the mechanical properties and processing properties are equivalent; and the modified anti-skid resins obtained in Examples 2, 3 and 6 have a gradually improved anti-skid performance compared with the resins of Comparative Examples 1, 2 and 3 according to the size trend of their resin Tg.

Therefore, the present invention starts from the theoretical basis of compatibility and Tg point, and prepares a modified resin with good compatibility and adjustable Tg value through a simple one-pot synthesis process to regulate the anti-slip performance of the composition without the need for solvents and catalysts. The modified resin can provide a modified resin with both compatibility and high Tg for each type of rubber.

The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A modified resin with anti-slip performance, characterized in that it is prepared by mixing the following components in weight percentage: 0%-30% of de-cyclized C5 petroleum resin, 15%-55% of thermally polymerized C9 petroleum resin, and 30%-70% of a-methylstyrene and styrene copolymer resin. 2. A modified resin with anti-slip performance according to claim 1, characterized in that the number average molecular weight of the de-cyclized C5 petroleum resin is 450-650. 3. The modified resin with anti-slip performance according to claim 1, characterized in that the number average molecular weight of the thermally polymerized C9 petroleum resin is 400-600. 4. A modified resin with anti-slip performance according to claim 1, characterized in that: the number average molecular weight of the copolymer resin of a-methylstyrene and styrene is 450-650, and the proportion of styrene in the copolymer resin is 20wt%-80wt%. 5. A method for preparing a modified resin having anti-slip performance according to any one of claims 1 to 4, characterized in that it comprises the following steps: (1) heating and melting a-methylstyrene and styrene copolymer resin; (2) adding de-cyclized C5 petroleum resin and thermally polymerized C9 petroleum resin to the above molten resin and reacting under controlled temperature; (3) After the reaction is completed, the modified resin product is obtained by transferring the material, granulating and packaging. 6. The method for preparing a modified resin with anti-slip performance according to claim 5, characterized in that the heating and melting temperature is 200-250°C and the time is 0.5-1.5h. 7. The method for preparing a modified resin with anti-slip performance according to claim 5, characterized in that the temperature of the temperature-controlled reaction is 200-250°C and the time is 2-5 hours. 8. Use of a modified resin having anti-skid performance as claimed in any one of claims 1 to 4 in the preparation of a rubber composition.