CN104672393A - Surface grafting modification process for waste tire rubber powder for asphalt modification - Google Patents

Abstract

The invention relates to a surface grafting modification process for waste tire rubber powder for asphalt modification. The surface grafting modification process specifically comprises the following steps: dispersing waste tire rubber powder in water, adding a certain amount of benzoyl peroxide and styrene, and stirring for 1-12 hours at constant temperature at 80-120 DEG C, wherein benzoyl peroxide accounts for 1.7-10% of the mass of the rubber powder, and styrene accounts for 1-30% of the mass of the rubber powder. When the grafted rubber powder is adopted as an asphalt modifier for preparing rubber powder modified asphalt by using a wet method modification process, the property of the modified asphalt can be conditioned and controlled. The surface grafting modification process is simple to operate and low in cost, and main properties such as the needle penetration degree, the ductility, the softening point and the like of the rubber powder modified asphalt can be effectively conditioned and controlled.

Description

A Surface Grafting Modification Process of Waste Tire Rubber Powder for Asphalt Modification

technical field

The invention relates to a surface graft modification process of waste tire rubber powder for asphalt modification. Specifically, it adopts the method of polymerization and grafting to graft polystyrene segments to the surface of waste tire rubber powder to regulate the performance of rubber powder modified asphalt.

Background technique

With the rapid development of the automobile industry and the gradual increase of the number of national automobiles, the annual waste tires produced in my country are increasing at a rate of about 6%-8%. According to statistics, in 2013, my country produced a total of 299 million waste tires (about 10.8 million tons), and has become the country that produces the most waste tires in the world. Waste tires have complex components and are not easy to degrade. A large amount of waste tires accumulates in the environment not only occupies land resources, but also causes environmental pollution. However, my country's rubber resources are very scarce. Therefore, improving the comprehensive utilization rate of waste tire resources has become an urgent problem to be solved.

The use of petroleum asphalt as a road paving material has a long history, but with the increase in traffic volume, people put forward higher requirements on the performance of the road surface. Studies have shown that the use of waste tire rubber powder to make modified asphalt can improve the high-temperature stability, low-temperature crack resistance, aging resistance and durability of asphalt, and can effectively reduce road noise, reduce road reflection, and improve road anti-skid effect. of general concern. However, due to factors such as poor compatibility between rubber powder and asphalt, the application of rubber powder modified asphalt is limited. By grafting polystyrene segments onto the surface of waste tire rubber powder, a surface network structure similar to that of SBS-modified asphalt can be formed between rubber powder and asphalt, thereby improving the performance of rubber powder-modified asphalt.

Contents of the invention

The invention provides a simple and industrially applicable waste tire rubber powder surface graft modification process for asphalt modification.

The technical scheme adopted in the present invention is: disperse waste tire rubber powder in water, add a certain amount of initiator and surface modifier, stir at constant temperature for 1-12 hours, the temperature is 80-120 ° C, the amount of initiator accounts for the amount of styrene 1.7%-10% of the surface modifier, the amount of surface modifier is 1%-300% of the rubber powder mass. After the reaction, the waste tire rubber powder is suction filtered, washed, dried, weighed, and the mass grafting rate is measured to obtain the grafted rubber powder. Graft rubber powder was modified by wet method to prepare rubber powder modified asphalt, and its main performance indicators were tested. The mixing amount of waste tire rubber powder in the rubber powder modified asphalt is 12.5wt%-21wt%.

The initiator is benzoyl peroxide, and the dosage is 1.7%-10% of that of styrene.

The surface modifier is styrene, and the dosage is 1%-300% of the mass of the rubber powder.

The reaction temperature is 80-120°C.

The mass grafting rate=(mass after grafting−mass before grafting)/mass before grafting. the

The particle size of the waste tire rubber powder is 16-60 mesh, and the source of the rubber powder is waste tire crushing.

The reaction time is 1-12 hours.

The base asphalt is road asphalt.

The technical flow chart of the waste tire rubber powder modified asphalt wet modification process is shown in Figure 1.

The main performance indicators of the asphalt include penetration at 25°C, ductility at 5°C, and softening point. Penetration at 25°C is an index that indicates the degree of softness and consistency of asphalt, the ability to resist shear damage, and reflects the relative viscosity of asphalt under certain conditions. The ductility at 5°C indicates the tensile strength of asphalt, and the greater the ductility, the better the low-temperature performance; the softening point indicates the high-temperature stability, and the larger the softening point, the better the high-temperature stability.

The present invention has the following advantages:

1. Realize the surface modification of waste tire rubber powder by means of polymerization and grafting. Styrene is used as a grafting monomer, benzoyl peroxide is used as an initiator, and polystyrene segments are grafted onto the surface of waste tire rubber powder at a certain temperature. Applying the grafted rubber powder to modified asphalt can form a surface network structure similar to SBS modified asphalt between the rubber powder and asphalt, making the rubber powder and asphalt stable and compatible, thereby improving the performance of the modified asphalt and stability.

2. Control the performance index of rubber powder modified asphalt. By grafting different proportions of polystyrene segments on the surface of the rubber powder, the compatibility between the rubber powder and asphalt can be adjusted, so as to realize the control of the 25°C penetration, 5°C ductility and softening point of the modified asphalt.

3. Easy to operate and industrial application. The treatment technology adopted in the invention is simple, low in cost, easy to operate, and can realize industrial application.

Description of drawings

Figure 1 is the wet modification process of rubber powder modified asphalt.

Detailed ways

Further describe the feature of the present invention by embodiment below, but the present invention is not limited to following example.

Example 1

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 300mL of styrene in 400mL of water, and react at 120°C for 12 hours under constant stirring. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of the rubber powder was measured to be 67.2%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. It is measured that the penetration at 25°C is 42 (0.1 mm), the ductility at 5°C is 7.6 (cm), and the softening point is 67.4 (°C).

Example 2

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 300mL of styrene in 400mL of water, and react for 2 hours under constant stirring at 120°C. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of the rubber powder was measured to be 6.4%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. The measured penetration at 25°C is 43 (0.1 mm), the ductility at 5°C is 7.4 (cm), and the softening point is 65.6 (°C).

Example 3

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 300mL of styrene in 400mL of water, and react at 120°C for 6 hours under constant stirring. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of rubber powder was measured to be 36.1%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. The measured penetration at 25°C is 49 (0.1 mm), the ductility at 5°C is 11 (cm), and the softening point is 68.5 (°C).

Example 4

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 200mL of styrene in 400mL of water, and react at 120°C for 12 hours under constant stirring. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of rubber powder was measured to be 43.3%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. It is measured that the penetration at 25°C is 46 (0.1 mm), the ductility at 5°C is 9.2 (cm), and the softening point is 67.5 (°C).

Example 5

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 200mL of styrene in 400mL of water, and react for 8 hours under constant stirring at 120°C. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of rubber powder was measured to be 18.0%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process. The mixing amount of waste tire rubber powder was 12.5wt%. ductility and softening point. It is measured that the penetration at 25°C is 41 (0.1 mm), the ductility at 5°C is 8.3 (cm), and the softening point is 65.9 (°C).

Example 6

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 100mL of styrene in 400mL of water, and react for 6 hours under constant stirring at 120°C. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of the rubber powder was measured to be 4.2%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. It is measured that the penetration at 25°C is 40 (0.1 mm), the ductility at 5°C is 7.4 (cm), and the softening point is 69.2 (°C).

Example 7

Disperse 100g of waste tire rubber powder, 5g of benzoyl peroxide and 100mL of styrene in 400mL of water, and react at 120°C for 10 hours under constant stirring. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. The mass grafting rate of the rubber powder was measured to be 11.0%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. It is measured that the penetration at 25°C is 45 (0.1 mm), the ductility at 5°C is 8.9 (cm), and the softening point is 67.9 (°C).

Example 8

Disperse 100g of waste tire rubber powder, 0.1g of benzoyl peroxide and 1mL of styrene in 400mL of water, and react at 120°C for 6 hours under constant stirring. The reacted waste tire rubber powder is filtered, washed, and dried at 80°C until the quality is constant to obtain the modified rubber powder. It is measured that the mass grafting rate of rubber powder is less than 1%. The modified rubber powder and Binyang No. 70 asphalt were prepared by wet modification process, and the mixing amount of waste tire rubber powder was 21wt%. degree and softening point. It is measured that the penetration at 25°C is 42 (0.1 mm), the ductility at 5°C is 7.3 (cm), and the softening point is 65.9 (°C).

Claims (9)

1. A surface graft modification process of waste tire rubber powder for asphalt modification, the specific steps comprising: dispersing waste tire rubber powder in water, adding initiator and surface modifier, stirring at constant temperature for 1-12 hours, temperature The temperature is 80-120°C, the dosage of the initiator is 1.7%-10% of the mass of the rubber powder, and the dosage of the surface modifier is 1%-300% of the mass of the rubber powder. After the reaction, the mass grafting rate is measured. 2. a kind of graft rubber powder prepared by process as claimed in claim 1. 3. a preparation process of modified asphalt, the graft rubber powder described in claim 2 is prepared rubber powder modified asphalt by wet process modification, and detects its main performance index, waste tires in rubber powder modified asphalt The blending amount is 12.5wt%-21wt%. 4. a kind of modified asphalt prepared by process as claimed in claim 3. 5. according to claim 1, a kind of surface graft modification process of waste tire rubber powder for asphalt modification is characterized in that said surface modifier is styrene, and the consumption is 1%-1% of the waste tire rubber powder quality. 300%. 6. the preparation technology of modified asphalt according to claim 3 is characterized in that described asphalt is road asphalt. 7. A surface graft modification process of waste tire rubber powder for asphalt modification according to claim 1, characterized in that the temperature is 80-120°C. 8. The surface grafting modification process of a kind of waste tire rubber powder for asphalt modification according to claim 1, characterized in that the particle diameter of the waste tire rubber powder is 16-60 mesh, preferably 40 mesh, and the rubber powder The source is waste tire crushing. 9. The surface graft modification process of a kind of asphalt modification waste tire rubber powder according to claim 1, characterized in that the initiator is benzoyl peroxide, and the initiator consumption is 1.7% of the rubber powder quality -10%.