CN112745691B

CN112745691B - Modified asphalt with stable thermal storage prepared from two end group polarized SBS

Info

Publication number: CN112745691B
Application number: CN201911045350.9A
Authority: CN
Inventors: 李静静; 邵磊山
Original assignee: China Petroleum and Chemical Corp
Current assignee: China Petroleum and Chemical Corp
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2022-06-14
Anticipated expiration: 2039-10-30
Also published as: CN112745691A

Abstract

The invention discloses modified asphalt with stable thermal storage and a preparation method thereof, wherein the modified asphalt with stable thermal storage comprises the following components in percentage by mass: 92-96% of matrix asphalt; 3-8% of SBS modifier; 0-3% of compatilizer; 0 to 0.4 percent of stabilizer; wherein the SBS modifier comprises a linear end hydroxylated SBS and a linear end epoxidized SBS. The modified asphalt provided by the invention has good thermal storage stability, the difference of the segregation softening points of the modified asphalt with the thermal storage stability is less than or equal to 2.5 ℃, the modified asphalt meets the national standard, has good storage stability, obviously improves the low-temperature cracking and fatigue resistance of the pavement, expands the application range and is beneficial to the industrial production of the modified asphalt.

Description

Modified asphalt with stable thermal storage prepared from two end group polarized SBS

Technical Field

The invention relates to modified asphalt with stable thermal storage, in particular to SBS modified asphalt with two terminal groups polarized. Meanwhile, the invention also relates to a preparation method of the modified asphalt.

Background

Road transportation is one of the most important modes of land transportation, the contribution of the road transportation to the development of socioeconomic performance is witnessed, and since the new century, roads, particularly expressways, in China are developed greatly, but the current people still have no reduction in the increasing transportation demand, the road transportation economy in China still needs to be developed urgently, and higher requirements are put forward on the roads.

The common asphalt is generally used at present because the common asphalt has the defects of unstable thermal storage, brittle low temperature and the like, and cannot meet the requirements of high roads and the like. Styrene-butadiene-styrene block copolymer (SBS) has two performances of rubber and plastic due to its unique structure, has rubber elasticity at normal temperature, and can become a plastic material at high temperature. SBS is used as modifier for modified asphalt, and the prepared modified asphalt has excellent high and low temperature performance, and can raise the ageing resistance and fatigue resistance of asphalt and become the main modifier for modified asphalt in China.

However, SBS is a high polymer and a non-polar polymer, and has large difference in physical and chemical properties such as molecular weight and density with polar matrix asphalt, so that the compatibility with the matrix asphalt is poor, and the modified asphalt may undergo phase separation during high-temperature storage, transportation and the like, resulting in poor asphalt performance, reduced low-temperature ductility, easy cracking, high temperature sensitivity, and further affecting the quality and normal use of the asphalt. Therefore, the SBS modified asphalt still has certain limitations, and the compatibility of SBS and the asphalt needs to be improved, and the low temperature of the modified asphalt needs to be improved, so that the phenomena of cracking and brittleness of the modified asphalt at low temperature can be solved, and the fatigue resistance of the modified asphalt is improved.

At present, the method for modifying the asphalt by modifying the SBS is very complex, the integral integrity of the SBS can be influenced, and the modification is greatly reduced, so that the characteristics such as the thermal storage stability and the like are poor.

Disclosure of Invention

In view of the defects of the existing modified asphalt, the invention provides the modified asphalt prepared by the two types of end group polarized SBS and the preparation method thereof, the modified asphalt provided by the invention or the modified asphalt prepared by the preparation method has good low-temperature cracking and fatigue resistance and good storage stability, and is beneficial to industrial production and application of the modified asphalt.

Therefore, the first aspect of the invention provides a modified asphalt prepared by two kinds of end group polarized SBS, wherein the modified asphalt comprises the following components in percentage by mass:

wherein the SBS modifier comprises linear end hydroxylated SBS and linear end epoxidized SBS.

In the invention, the inventor researches and discovers that the SBS modifier combined with the linear-end hydroxylated SBS and the linear-end epoxidized SBS in a certain weight ratio can be added, so that the thermal storage stability of the modified asphalt can be obviously improved, and better low-temperature cracking resistance and fatigue resistance can be maintained or obtained. In some embodiments, the SBS modifier consists of linear end-hydroxylated SBS and linear end-epoxidized SBS. Preferably, in the SBS modifier, a weight ratio of the linear-end hydroxylated SBS to the linear-end epoxidized SBS is 0.8 to 5. More preferably, the weight ratio of the linear-end hydroxylated SBS to the linear-end epoxidized SBS is 2 to 4.

In the present invention, the base asphalt may be a base asphalt conventionally used in the art, for example, the base asphalt is 70# base asphalt for roads.

In the present invention, the linear-end-hydroxylated SBS and the linear-end-epoxidized SBS are important for solving the technical problems of the present invention, and preferably, the linear-end-hydroxylated SBS has an average molecular weight of 8 to 12 ten thousand, is not oil-extended, and has a block ratio S/B of 3/7; the linear end-epoxidization has an average molecular weight of 8 to 12 ten thousand, is not oil-extended, and has a block ratio S/B of 3/7.

The preparation method of the linear end hydroxylated SBS (SBS-OH) comprises the following steps: styrene and butadiene are used as monomer raw materials, cyclohexane is used as a solvent, organic lithium is used as an initiator, and Tetrahydrofuran (THF) is used as an activating agent, and SBS is synthesized by adopting a three-stage feeding mode; after the third stage of reaction, adding propylene oxide to carry out end capping, terminating by using ethanol after the polymerization is finished, adding an anti-aging agent, uniformly mixing, and removing the solvent to obtain SBS-OH.

The preparation method of the linear terminal epoxy SBS (SBS-O-epoxy) comprises the following steps: styrene and butadiene are used as monomer raw materials, cyclohexane is used as a solvent, organic lithium is used as an initiator, and Tetrahydrofuran (THF) is used as an activating agent, and SBS is synthesized by adopting a three-stage feeding mode; after the third stage of reaction, adding ethylene oxide, then adding epichlorohydrin, after the polymerization is finished, stopping with ethanol, then adding an anti-aging agent, uniformly mixing, and removing the solvent to obtain SBS-O-epoxy.

In some embodiments of the invention, the compatibilizer may be a furfural extract oil.

In some embodiments of the invention, the stabilizer may be a sulfide, such as BHS-2A from the institute of petrochemical science, Beijing.

The modified asphalt provided by the invention has the segregation softening point difference of less than or equal to 2.5 ℃.

In a second aspect, the present invention provides a method for preparing the modified asphalt with stable thermal storage according to the first aspect, wherein the method comprises the following steps:

(1) taking matrix asphalt, and heating to be molten;

(2) adding a compatilizer, linear terminal hydroxylated SBS and linear terminal epoxidized SBS, stirring and premixing, and then shearing at high speed for 20-30 min;

(3) adding stabilizer, shearing at high speed for 8-12min, and stirring for 4-5 hr to obtain modified asphalt with stable thermal storage;

wherein, the stirring speed of the stirring and premixing in the step (2) is 150-; the shearing rate of the high-speed shearing in the steps (2) and (3) is 2500-3000r/min, and the shearing temperature is 170-180 ℃; the stirring speed of the stirring development in the step (3) is 90-120r/min, and the development temperature is 170-180 ℃.

The invention has the beneficial effects that:

(1) the SBS modifier with specific molecular weight has terminal groups of-OH and epoxy groups and has polarity, and may form network structure with polar groups or physical adsorption or chemical covalent bond to form homogeneous stable spatial three-dimensional network structure system in asphalt.

(2) The modified asphalt with stable thermal storage provided by the invention has the segregation softening point difference of less than or equal to 2.5 ℃, meets the national standard, has good storage stability, can obviously improve the low-temperature cracking and fatigue resistance of the pavement, expands the application range and is beneficial to the industrial production of the modified asphalt.

Detailed Description

In order that the present invention may be more readily understood, the following detailed description of the invention is given with reference to specific examples, which are intended to be illustrative only and are not intended to limit the scope of the invention. The starting materials or components used in the present invention may be commercially or conventionally prepared unless otherwise specified.

The invention is further illustrated in the following examples and comparative examples using a Nominal petrochemical road asphalt No. 70 base asphalt as an example, the performance indexes of which are shown in Table 1. The compatilizer is provided by the famous petrochemical industry for the furfural extract oil, and the performance preparation of the compatilizer is shown in table 2. The stabilizer is sulfide BHS-2A, provided by Beijing institute of petrochemical engineering science and technology, and the performance preparation thereof is shown in Table 3.

TABLE 1 Property index of Mooney petrochemical No. 70 base asphalt

TABLE 2 Main physicochemical Properties of Carnation's petrochemical furfural extract oil

The stabilizer is BHS-2A provided by Beijing institute of petrochemical engineering science and technology, and the basic properties are shown in Table 3.

TABLE 3 modified asphalt stabilizer Properties

In the examples and the comparative examples, SBS-OH and SBS-O-epoxy are prepared by adopting an anionic polymerization three-step method: polymerizing in a 10L anion polymerization kettle under the protection of high-pressure nitrogen, wherein the pressure is 0.4MPa, the mass ratio of styrene to butadiene is 3:7, and the mass percent of the monomers is 15%. Adding cyclohexane, metered styrene and a small amount of THF (tetrahydrofuran) into a polymerization kettle, heating, adding n-butyllithium at a certain temperature to break impurities, and removing the impurities of the system when the system is unchanged from colorless to light yellow, wherein the amount of the n-butyllithium consumed is the impurity breaking amount. Then adding n-butyl lithium (effective lithium) with initiation amount rapidly at 60 ℃ according to the designed relative molecular mass for initiation, adding a certain amount of propylene oxide for end capping after the third stage reaction, terminating with excessive ethanol after the polymerization is finished, adding the anti-aging agent 2, 6-di-tert-butyl-p-cresol (anti-aging agent 264), and boiling the polymer solution with steam to remove the solvent to obtain SBS-OH. The molar ratio of THF to available lithium was 0.3 and the molar ratio of propylene oxide to available lithium was 1.2: 1. The molar ratio of the terminating agent ethanol to available lithium is 1: 1. The amount of the antioxidant was 0.6% by mass of the final product of the polymerization. The SBS-O-epoxy is prepared through the third stage reaction, adding epoxy ethane to deactivate, adding epoxy chloropropane to terminate, adding antioxidant 2, 6-ditert-butyl-p-cresol (antioxidant 264), and boiling polymer solution with water vapor to eliminate solvent to obtain SBS-OH. The molar ratio of THF to available lithium was 0.3 and the molar ratio of ethylene oxide to available lithium was 1.2: 1. The molar ratio of epichlorohydrin to available lithium was 1.3: 1. The amount of the antioxidant was 0.6% by mass of the final product of the polymerization.

The amount of available lithium, i.e., n-butyllithium as the initiator, can be determined based on the number average molecular weight (Mn) of the SBS and the total monomer amount of styrene and butadiene, which is expected to be obtained, i.e., calculated using equation I below:

formula I: v initiator ═ m/Mn)/C

Wherein V is the volume of the initiator; m is the mass of styrene and butadiene monomers; mn is the number average molecular weight of the designed SBS; and C is the molar concentration of the initiator.

Example 1

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

(2) then adding furfural extract oil, SBS-OH and SBS-O-epoxy, stirring and premixing for 1h at 200r/min, and shearing at high speed of 175 +/-5 ℃ for 25min at the shearing rate of 2500 r/min;

(3) adding stabilizer (BHS-2A), continuing high-speed shearing for 10min, and then developing at 175 + -5 deg.C and stirring rate of 100r/min for 4.5h to obtain modified asphalt (properties are shown in Table 4).

Wherein the mass percentages of the components are respectively as follows: 94.5 percent of matrix asphalt and 2.8 percent of SBS-OH; SBS-O-epoxy 1.5%, furfural extract oil 1%, BHS-2A 0.2%; the average molecular weight of the linear end-hydroxylated SBS is 10 ten thousand, the SBS has no oil charge, and the block ratio S/B is 3/7; the average molecular weight of the linear terminal epoxy group is 10 ten thousand, and the matrix asphalt is 70# matrix asphalt.

Example 2

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

Wherein the mass percentages of the components are respectively as follows: 93.8 percent of matrix asphalt and 2.5 percent of SBS-OH; SBS-O-epoxy 1.5%, furfural extract oil 2%, BHS-2A 0.2%; the average molecular weight of the linear end-hydroxylated SBS is 10 ten thousand, the SBS has no oil charge, and the block ratio S/B is 3/7; the average molecular weight of the linear terminal epoxy group is 10 ten thousand, and the matrix asphalt is 70# matrix asphalt.

Example 3

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

Wherein the mass percentages of the components are respectively as follows: 96% of matrix asphalt and SBS-OH 2%; SBS-O-epoxy 1%, furfural extract oil 0.8%, BHS-2A 0.2%; the average molecular weight of the linear end-hydroxylated SBS is 10, it is not oil-extended, and the block ratio S/B is 3/7; the average molecular weight of the linear terminal epoxy group is 10, and the matrix asphalt is No. 70 matrix asphalt.

Example 4

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

Wherein the mass percentages of the components are respectively as follows: 92% of matrix asphalt, and 4% of SBS-OH; SBS-O-epoxy 2%, furfural extract oil 1.6%, BHS-2A 0.4%; wherein the matrix asphalt is 70# matrix asphalt.

Comparative example 1

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

(2) then adding furfural extract oil and SBS-O-epoxy, stirring and premixing for 1h at 200r/min, and shearing at high speed of 175 +/-5 ℃ for 25min at the shearing rate of 2500 r/min;

Wherein the mass percentages of the components are respectively as follows: 94.5 percent of matrix asphalt, 4.3 percent of SBS-O-epoxy, 1 percent of furfural extract oil and 0.2 percent of BHS-2A; the average molecular weight of the linear terminal epoxy group is 10 ten thousand, and the matrix asphalt is 70# matrix asphalt.

Comparative example 2

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

(2) then adding furfural extract oil and SBS-OH, stirring and premixing for 1h at 200r/min, and shearing at high speed of 175 +/-5 ℃ for 25min at the shearing rate of 2500 r/min;

Wherein the mass percentages of the components are respectively as follows: 94.5 percent of matrix asphalt, 4.3 percent of SBS-OH, 1 percent of furfural extract oil and 0.2 percent of BHS-2A; the average molecular weight of the linear end-hydroxylated SBS is 10 ten thousand, the SBS has no oil charge, and the block ratio S/B is 3/7; the matrix asphalt is No. 70 matrix asphalt.

Comparative example 3

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

(2) then adding furfural extract oil and common linear SBS, stirring and premixing for 1h at 200r/min, and shearing at high speed of 175 +/-5 ℃ for 25min at the shearing rate of 2500 r/min;

Wherein the mass percentages of the components are respectively as follows: 94.5 percent of matrix asphalt, 4.3 percent of SBS, 1 percent of furfural extract oil and 0.2 percent of BHS-2A; the average molecular weight of the common linear SBS is 10 ten thousand, the SBS is not oil-extended, and the block ratio S/B is 3/7; the matrix asphalt is No. 70 matrix asphalt.

The modified asphalts of the examples and comparative examples were tested and the specific results are shown in Table 4.

TABLE 4

As is apparent from comparative analysis of data in Table 4, the modified asphalts prepared in examples 1-4 of the present invention have segregation softening points with differences less than 2.5 ℃ specified for road traffic, low temperature ductility (5 ℃) greater than 22cm, TFOT post-ductility greater than 15cm, meet I-D standards, and have performance superior to comparative examples.

Example 5

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

Wherein the mass percentages of the components are respectively as follows: 95.3 percent of matrix asphalt and 2.5 percent of SBS-OH; SBS-O-epoxy 1%, furfural extract oil 1%, BHS-2A 0.2%; the average molecular weight of the linear end-hydroxylated SBS is 8 ten thousand, the SBS has no oil charge, and the block ratio S/B is 3/7; the average molecular weight of the linear terminal epoxy group is 8 ten thousand, and the matrix asphalt is No. 70 matrix asphalt.

Example 6

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

Wherein the mass percentages of the components are respectively as follows: 94.3 percent of matrix asphalt and 3 percent of SBS-OH; SBS-O-epoxy 1%, furfural extract oil 1.5%, BHS-2A 0.2%; the average molecular weight of the linear end hydroxylated SBS is 12 ten thousand, no oil charge, block ratio S/B3/7; the average molecular weight of the linear terminal epoxy group is 12 ten thousand, and the matrix asphalt is 70# matrix asphalt.

Example 7

(1) Heating 70# matrix asphalt to 185 +/-5 ℃ for melting;

Wherein the mass percentages of the components are respectively as follows: 92.8 percent of matrix asphalt and 4 percent of SBS-OH; SBS-O-epoxy 1%, furfural extract oil 2%, BHS-2A 0.2%; the average molecular weight of the linear end hydroxylated SBS is 10 ten thousand, is not oil extended, and the block ratio S/B is 3/7; the average molecular weight of the linear terminal epoxy group is 10 ten thousand, and the matrix asphalt is 70# matrix asphalt.

The modified asphalts of examples 6-7 were tested and the specific results are shown in Table 5.

TABLE 5

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof, and the above-described embodiments of the present invention are to be considered in all respects as illustrative and not restrictive, e.g., the base asphalt may be other than the 70# base asphalt for road use. Therefore, any minor modifications, equivalent changes and modifications to the above embodiments according to the spirit of the present invention shall fall within the protection scope of the present invention.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims

1. The modified asphalt with stable thermal storage prepared from two terminal group polarized SBS is characterized by comprising the following components in percentage by mass:

94.5% of No. 70 matrix asphalt;

4.3 percent of SBS modifier;

1% of furfural extract oil;

0.2 percent of sulfide BHS-2A;

the SBS modifier comprises linear terminal hydroxylated SBS and linear terminal epoxidized SBS, wherein the linear terminal hydroxylated SBS is 2.8%, and the linear terminal epoxidized SBS is 1.5%; the average molecular weight of the linear end hydroxylated SBS is 10 ten thousand, the SBS has no oil charge, and the block ratio S/B = 3/7; the average molecular weight of the linear-end epoxidized SBS is 10 ten thousand.

2. The modified asphalt of claim 1, wherein the linear terminally epoxidized SBS is not oil extended and has a block ratio S/B = 3/7.

3. The modified thermal storage-stable asphalt according to claim 1 or 2, wherein the modified thermal storage-stable asphalt has an segregation softening point difference of 2.5 ℃ or less.

4. A method for producing a modified asphalt having stable thermal storage according to any one of claims 1 to 3, characterized by comprising the steps of:

(1) taking matrix asphalt, and heating to melt;

(3) adding stabilizer, high-speed shearing for 8-12min, stirring and developing for 4-5 hr to obtain modified asphalt with stable thermal storage

Wherein, the stirring speed of the stirring and premixing in the step (2) is 150-250r/min, the premixing time is 0.5-2h, and the premixing temperature is 180-190 ℃; the shearing rate of the high-speed shearing in the steps (2) and (3) is 2500-3000r/min, and the shearing temperature is 170-180 ℃; the stirring speed of the stirring development in the step (3) is 90-120r/min, and the development temperature is 170-180 ℃.