CN1247642C - Monomorphic radial block copolymer containing random gradient segments and preparation method thereof - Google Patents

Abstract

The invention provides a unimodal radial block copolymer containing random gradual change chain segment and a preparation method thereof, and the structural formula of the block copolymerIs represented as follows: R-X * B₃-(B₂-S₃)B₁/S₂-S₁]₃The weight portion of the monovinylarene monomer contained in the copolymer is 30-95%, the weight portion of the conjugated diene monomer is 5-70%, the molecular weight of the polymer is 160000-220000, the random gradual change chain segment of the polymer is obtained by adopting the polymerization temperature of 65-100 ℃, the feeding speed of the mixture of the monovinylarene and the conjugated diene is 4.6-9.5%/min in terms of the weight percentage of the mixture, the feeding speed of the monovinylarene is lower than the reaction rate, and the feeding speed of the conjugated diene is higher than the reaction rate. The polymer has high light transmittance and excellent impact strength, has good elasticity at normal temperature and environmental cracking resistance of products, can be plasticized and formed at high temperature, and can be used in the fields of food packaging, medical instruments, toys for children and the like.

Description

Monomorphic radial block copolymer containing random gradient segments and preparation method thereof

technical field

The invention relates to a single-morphological radial block copolymer containing random gradient segments and a preparation method thereof, in particular to a highly transparent, impact-resistant single-morphology radial or block copolymer with random gradient segments. It is called star block copolymer and its preparation method.

Background technique

In the prior art, there are many relevant documents reporting on butadiene-styrene block copolymers, such as EP0492490, US 4925899, US 5130377, CN 85100418, etc. Patent CN 1073950 reports a method for preparing a butadiene-styrene block copolymer. The initiator is added once, and the copolymer is obtained through a coupling reaction, but the molecular chain of the copolymer does not contain a gradient segment, so the coupling efficiency is low , the coupling reaction time is long. The butadiene-styrene block copolymers reported in US 4925899, US 5130377, and CN 85100418 are polymorphic or multimodal. During preparation, not only the initiator is added in more than 2 times, but the monomer is added in 4 to 9 times. , The polymerization reaction stage takes a long time, the process is complicated, and the addition of monomers and initiators will inevitably bring impurities into the polymerization system, deactivate part of the active chain, and affect the quality and performance of the polymer.

In order to simplify the synthesis process and improve the quality of the polymer, CN 1241582A discloses a single-morphology three-arm star-shaped butadiene-styrene block containing a random tapered segment by adding the initiator once and adding the monomer four times. Copolymer method. The copolymer prepared by the above method has high impact strength, good light transmittance and environmental cracking resistance of products, and is especially suitable for the packaging field. However, the synthesis of the gradient segment adopts the temperature gradient polymerization method, that is, a random segment is formed at a high temperature, and a gradient segment is formed at a lower temperature. The operating temperature of this process is too high, prone to side reactions and gelation.

Synthesis of a transition segment in a copolymer of monovinylarene and conjugated diene, WO96/25442 reports the formation of a transition segment by prolonging the feeding time of butadiene, from continuous feeding of butadiene to discontinuous feeding, and discontinuous feeding of styrene It is obtained by changing to continuous feeding and controlling the polymerization temperature. This method takes a long time to feed and needs to realize alternate control, which is not conducive to industrial production. Patents EP761704A1, US5399628, etc. refer to the synthesis of the gradient section. In the synthesis of styrene and butadiene, they are mixed in a certain proportion, added at one time, and reacted at a constant temperature. The gradient section obtained by this method has a low degree of randomness and the gradual change process is not obvious. , affecting product performance.

Contents of the invention

The purpose of the present invention is to provide a monomorphic radial block copolymer containing random gradient segments and its preparation method, so that the polymer has high light transmittance and impact strength, and also has good high temperature resistance , heat and oxygen aging resistance and environmental cracking resistance of products, can be used in the field of packaging.

A kind of monomorphic radial block copolymer containing a random gradual change segment of the present invention, its structural formula is represented as follows:

Among them, S ₁ , S ₂ and S ₃ all represent monovinylarene-like hydrocarbons, B ₁ , B ₂ and B ₃ all represent conjugated dienes; R is a saturated aliphatic hydrocarbon group containing 1 to 6 carbon atoms, preferably methyl base; X=Si, Sn, preferably Si atom.

That is, it is synthesized by anionic polymerization technology, and the single-arm molecular chain contains a monovinyl arene homopolymerization segment and a monovinyl arene. A monomorphic radial block copolymer of a conjugated diene with a random tapered segment and a conjugated diene homopolymerized segment. The weight fraction of the monovinylarene monomer contained in the copolymer of the present invention is 30%～95% (wt), preferably 35%～85% (wt), the weight of conjugated diene monomer Parts are 5% to 70% (wt), preferably 15% to 65% (wt), and the molecular weight of the polymer is 160000 to 220000; 65 ℃ ~ 100 ℃, the method of controlling the feeding speed of the mixture of monovinylarene and conjugated diene is realized. The mixture of monovinylarene and conjugated diene is added in two batches, and the feeding rate of the first batch of the mixture, that is, the feeding rate of monovinyl arene and conjugated diene in the random segment synthesis, is lower than that of the remaining mixture, that is, the gradual segment synthesis The feeding speed, the feeding speed is 4.6%～9.5%/min in terms of the weight percentage of the mixture, according to the difference of polymerization temperature, the former feeding speed is lower than the reaction rate, and the latter feeding speed is higher than the reaction rate.

Specifically, the copolymer of the present invention can be obtained by adding the initiator once, adding the monomer into the polymerization system in a certain order in four times, and adding a coupling agent after the polymerization to carry out a coupling reaction to obtain . The synthesis of the random gradient segment of the copolymer of the present invention is realized by controlling the feeding speed. The monomers for polymerization are conjugated dienes and monovinylarene monomers, and the order of addition is as follows:

Step 1: Monovinylarene monomer S ₁ and initiator L form S ₁ -Me (Me is the metal ion of initiator);

Step II: monovinylarene monomer S ₂ and conjugated diene monomer B ₁ to form S ₁ -B ₁ /S ₂ -Me:

Step III: monovinylarene monomer S ₃ and conjugated diene monomer B ₂ to form S ₁ -B ₁ /S ₂ (B ₂ →S ₃ )-Me;

Step IV: Conjugate diene monomer B ₃ to form active chain P: S ₁ -B ₁ /S ₂ (B ₂ →S ₃ )-B ₃ -Me;

Step V: Functionalize Coupler C to form:

In the formula, R is a saturated aliphatic hydrocarbon group containing 1 to 6 carbon atoms, preferably a methyl group; X=Si, Sn, preferably an Si atom.

In each step, the polymerization reaction is carried out until substantially no free monomer exists, and the polymerization temperature is 60°C to 120°C, preferably in the range of 65°C to 95°C.

The formation of the random gradual change segment in the polymer of the present invention adopts continuous feeding at a relatively mild temperature, and the feed rate and feed amount are controlled in sections to obtain a random gradient with a certain length of the random segment and the gradual change segment closely connected. chain segment. The random gradient segment prepared by this process has a high degree of randomization, which fully realizes the gradual transition from randomization to butadiene to styrene, and effectively avoids the formation of gel or other side effects under high temperature reaction. The occurrence of the reaction ensures that the polymer has good light transmittance and excellent mechanical and mechanical properties.

The polymkeric substance of the present invention can be thermoplastic elastomer, also can be thermoplastic resin, and polymkeric substance performance characteristic is by the total proportioning of monovinyl arene and conjugated diene in the polymkeric substance and the length of the random gradient chain segment, monomer ratio and The mixed monomer feed rate is determined.

In order to make the polymer have excellent properties, the present invention provides its optimal preparation method.

When the monomorphic radial block copolymer containing random gradient segments of the present invention is a thermoplastic elastomer copolymer, the weight fraction of monovinylarene in the copolymer is 30% to 60%, preferably 35% to 55%, and the weight fraction of the conjugated diene monomer is 40%-70%, preferably 45%-65%.

Preparation process is described as follows: (total monomer weight refers to all monomer total weights in the text)

First, 12.6% to 44.30%, preferably 15.0% to 40.5% of the total monomer weight, monovinylarene is added to the polymerization unit, and then an organic monoalkali metal initiator is added to form a non- Elastic segment, the structural formula is S ₁ -Me: then add a mixture of monovinylarene and conjugated diene to the polymerization system, the feeding speed is 4.6% to 8.4%/min in terms of weight percentage of the mixture, monoethylene in the mixture Base aromatics account for 15.7% to 47.4% (Wt) of the total monomer weight, preferably 18.5% to 42.0% (Wt), and conjugated dienes account for 32.6% to 67.9% (wt) of the total monomer weight, preferably It is 44.7% to 61.2% (Wt). The feeding rate of the random segment synthesis is lower than that of the gradual segment synthesis. According to the different polymerization temperatures, the feeding rate of the former is lower than the reaction rate, and the feeding rate of the latter is higher than the reaction rate. The feeding method recommended by the present invention is: the injection rate of the mixture is relatively slow at the beginning, which is 4.6%-6.5%/min, and when about 70%-85% of the mixture is injected, the injection rate is increased to 6.7%-8.4%/min, and the reaction temperature is 65～100℃. Continue to maintain the reaction for 10 to 30 minutes after the monomer mixture is added. In this way, a random gradient segment with a random segment of a certain length and a gradient segment of a certain length closely connected to each other can be synthesized, and the degree of randomization in this segment is relatively high, effectively completing the process from randomization to butadiene to benzene Vinyl gradient transition. At this time, the polymer can be expressed as S ₁ -B ₁ /S ₂ (B ₂ →S ₃ )-Me; and then account for 2.1% to 7.4% (Wt) of the total monomer weight, preferably 2.5% to 6.4% (Wt) conjugated diene is added to the polymerization system, so that the end of each polymer chain forms a very small conjugated diene segment to reduce the steric hindrance effect brought by the aryl group during coupling and ensure the coupling. Effectiveness, at this time the polymer chain can be expressed as S ₁ -B ₁ /S ₂ (B ₂ →S ₃ )-B ₃ -Me; finally use an alkoxysilane (or tin) alkane coupling agent for coupling Coupling, the coupling reaction can be completed at 70-90°C for 30-65 minutes. If without the coupling step, a linear block copolymer is obtained, the object of the present invention cannot be achieved. In order to improve the transparency of the polymer, the polymer solution after coupling is treated with water. The amount of water used is generally 100-300 times the amount of the initiator, preferably 150-250 times. At the same time, CO2 is used to adjust the pH value of the polymer solution. To 7.0±0.5, the polymer thus obtained has good transparency. In this way, a thermoplastic elastomer with high styrene content, high transparency, impact resistance, and single-morphological radial block copolymer containing a random gradient segment is prepared.

When the monomorphic radial block copolymer containing random gradient segments of the present invention is a thermoplastic resin copolymer, the weight fraction of monovinylarene in the copolymer is 60% to 95%, preferably 70% to 85%. %, the weight fraction of the conjugated diene monomer is 5%-40%, preferably 15%-30%.

The preparation process is described as follows:

First, 17.30% to 92.80% (Wt) of the total monomer weight, preferably 25.0% to 74.5% (Wt) of monovinylarene is added to the polymerization unit, and then an organic monoalkali metal initiator is added to form an active monomer. The non-elastic segment of the alkali metal end group, the structural formula is S ₁ -Me; after that, the mixture of monovinylarene and conjugated diene is continuously added to the polymerization system, and the feeding rate is 5.4% to 9.5% based on the weight percentage of the mixture. /min, the monovinylarene in the mixture accounts for 2.20% to 77.70% (Wt) of the total monomer, preferably 10.5% to 60.0% (Wt), and the conjugated diene accounts for 1.00% to 39.75% of the total monomer weight (wt), preferably 12.0% to 29.25% (wt). The mixture is injected continuously, and the feed rate of the random segment synthesis is lower than that of the gradient segment synthesis. According to the different polymerization temperatures, the former feed rate is lower than the reaction rate, and the latter feed rate is higher than the reaction rate. The feeding method recommended by the present invention is: the injection speed of the mixture is relatively slow at the beginning, and the feeding speed is calculated as 5.4% to 7.8%/min in terms of the weight percentage of the mixture. When about 70% to 85% of the mixture is injected, the injection speed is increased to 7.2% to 9.5%/min, the reaction temperature is 65-100°C. In this way, a random gradient segment with a random segment of a certain length and a gradient segment of a certain length closely connected to each other can be synthesized, and the degree of randomization in this segment is relatively high, effectively completing the process from randomization to butadiene to benzene Vinyl gradient transition. In this case, the polymer can be expressed as S ₁ -B ₁ /S ₂ (B ₂ →S ₃ )-Me. The random gradient segment is synthesized by this method, which can effectively ensure that the polymer has excellent mechanical and optical properties.

Then 0.25%～4.00% (Wt) of the total monomer weight, preferably 0.75%～3.00% (Wt) of conjugated diene is added to the polymerization system, so that the end of each polymer chain forms a small The conjugated diene chain segment of the conjugated diene to reduce the steric hindrance effect brought by the aryl group during coupling to ensure the effectiveness of the coupling; finally use a multi-active center silicon (or tin) alkane coupling with one or more functional groups Reagents are coupled. If without the coupling step, a linear block copolymer is obtained, the object of the present invention cannot be achieved. In this way, a monomorphic radial multi-arm block copolymer with a randomly tapered segment is obtained. In order to improve the transparency of the polymer, the coupled polymer solution is treated with water, the amount of water is generally 100 to 300 times the amount of the initiator, preferably 150 to 250 times, and the pH of the polymer solution is adjusted with _CO2 The obtained polymer has good transparency.

Add antioxidants to the polymer solution before the solvent is evaporated. The antioxidants can be 1076, 1010, 264, TNP, triisopropanolamine, etc. The above-mentioned substances can be used alone or in multiple combinations. The addition amount is 1-5 phm (phm is the weight part of the substance per 100 weight parts of total monomers, the same below), preferably 1-2 phm.

The separation of the polymer from the solution can adopt the traditional stripping and coagulation method, and a devolatilization screw extruder can also be used.

In the present invention, monovinylarene monomers generally refer to substances containing 8 to 18 carbon atoms, and the substituents can be alkyl, cycloalkyl, aromatic substituents and their composite substituents, wherein the total number of carbon atoms in the substituents is generally No more than 12. Mainly including styrene, α-methylstyrene, 4-n-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 1-vinylnaphthalene, 2,4-dimethylbenzene Ethylene, etc., or a mixture thereof. The most commonly used is styrene, which is determined by its practical value in industry.

The conjugated dienes of the present invention generally contain 4 to 12 carbon atoms, preferably 4 to 8 carbon atoms, including 1,3-butadiene, isoprene, 2,3-dimethyl-1,3 -butadiene, 3-butyl-1,3-octadiene, 2-phenyl-1,3-butadiene, etc., or a mixture thereof. Industrially valuable are 1,3-butadiene, isoprene, and 1,3-butadiene is most commonly used.

In the present invention, the molar ratio of monovinylarene to conjugated diene and the length of the random segment, that is, the percentage of the random segment in the random gradient segment, can be determined by the required mechanical properties of the polymer. Generally speaking, the greater the molar ratio of monovinylarene to conjugated diene, the lower the notched impact strength of the polymer and the greater the tensile strength, the longer the random segment, the greater the notched impact strength of the polymer and the greater the tensile strength of the polymer. The tensile strength is smaller. In the present invention, the recommended value of the molar ratio of styrene/butadiene in the random gradient segment is 0.2 to 1.5, and the preferred range is 0.3 to 1.2. The total amount of monomers in the random gradient segment accounts for the total monomer weight of the polymer 28.6% to 61.8% of the total.

The initiator used in the present invention is preferably an organic monolithium compound, commonly used is a hydrocarbyl monolithium compound, i.e. RLi, wherein R is a saturated aliphatic hydrocarbon group containing 1 to 20 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or A complex group of the above groups. Such organolithium compounds include n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, dodecyllithium and the like. The most commonly used are n-butyllithium and sec-butyllithium. The amount of organolithium added is determined by the molecular weight of the designed polymer. The molecular weight of the polymer recommended in the present invention is 160,000-220,000.

The coupling agent used in the present invention can be represented by the general formula: RX-(OR') ₃ , wherein R is a saturated aliphatic hydrocarbon group containing 1 to 6 carbon atoms, preferably a methyl group; R' is a saturated aliphatic hydrocarbon group containing 1 to 4 A saturated aliphatic hydrocarbon group of 2 carbon atoms, preferably a saturated aliphatic hydrocarbon group containing 1 to 2 carbon atoms; X=Si, Sn, preferably Si atom. Of course, the coupling agent can also be polyketones, polycarbonyl esters, polyepoxides, etc. containing multiple reaction centers. The amount of coupling agent depends on the amount of initiator, generally 1/4 to 1/3 of the amount of initiator.

The polymerization reaction of the present invention is carried out substantially in the absence of oxygen and water, preferably in an inert gas Ar environment. The polymerization process is carried out in hydrocarbon diluents, preferably hydrocarbon diluents include linear alkanes and cycloalkanes, such as pentane, hexane, octane, heptane, cyclohexane and their mixtures, preferably cycloalkanes hexane.

In the polymerization system of the present invention, a small amount of polar organic compound needs to be added as a randomizer. On the one hand, the reactivity of n-alkyllithium initiators such as n-butyllithium can be improved, and on the other hand, the randomness of the random gradient section can be adjusted. Degree of change and degree of gradation. Such polar organic compounds include tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether, triethylamine, Hexamethylphosphonotriamide, etc. Among them, tetrahydrofuran has the best effect, and its dosage range is 0.01-0.1 phm, preferably 0.02-0.08 phm.

After the monomorphic multi-arm radial block copolymer of the present invention is blended with polystyrene at 50%, its light transmittance maintains the original optical performance and can still reach more than 87%. The monomorphic radial block copolymer with random gradual change segment of the present invention can be made into a polymorphic compound with anti-fragmentation (higher impact strength, yield strength, tensile strength), almost colorless and transparent products, especially suitable for the field of packaging. The method for preparing the block copolymer provided by the invention has the characteristics of simple process, short polymerization time and stable product performance.

Description of drawings

Fig. 1 is the gel permeation chromatogram of embodiment 1 polymer.

FIG. 2 is a gel permeation chromatogram of the bimodal radial block copolymer of Comparative Example 3.

3 is a gel permeation chromatogram of the multimodal star block copolymer of Comparative Example 5.

Detailed ways

In order to further illustrate the details of the present invention, several examples and comparative examples are listed below, but should not be limited thereto.

Examples 1-10 describe the application of the preparation method of the present invention to synthesize high-molecular-weight monomorphic radial multi-arm radial block copolymers with random gradient segments.

Examples 1-10

In a jacketed 14L stainless steel reactor, the polymerization was carried out in a hydrocarbon solvent under the protection of argon. Continuous stirring of the reaction mixture is required during polymerization and coupling. Adding steps are as follows:

(1) monovinylarene monomer and initiator;

(2) A mixture of monovinylarene monomers and conjugated diene monomers (70% to 85% of the total weight of the mixture);

(3) A mixture of monovinylarene monomers and conjugated diene monomers (the remaining 15% to 30% mixture);

(4) conjugated diene monomer;

(5) Coupling agent.

After the coupling reaction is completed, the coupled reaction mixture is treated with water and CO ₂ , and an antioxidant is added before obtaining the polymer dry glue of the present invention. Table 1 shows the types of raw materials and additives used in Examples 1-10, and Table 2 shows the formulations and process conditions for preparing the copolymers of the present invention in Examples 1-10. In the examples, the copolymers of Examples 1-5 are thermoplastic resins, and the copolymers of Examples 6-10 are thermoplastic elastomers. Fig. 1 is the gel permeation chromatogram of embodiment 1 polymer.

Comparative example 1

Comparative Example 1 is to prepare a linear block copolymer with a single shape containing a random tapered segment. The difference from Example 1 is that the coupling agent added in step (5) is (CH ₃ ) ₂ SiCl ₂ , and the rest The kind and processing condition of raw material and auxiliary agent are identical with embodiment 1.

Comparative example 2

Comparative Example 2 is to prepare a star-shaped block copolymer with a single shape that contains a random gradient segment, and the difference from Example 1 is that the coupling agent added in step (5) is SiCl ₄ , the raw materials and auxiliary agents used The kind and processing condition are identical with embodiment 1.

Comparative example 3

Comparative Example 3 is a commercialized KR-03 that belongs to the same grade as the copolymer of the present invention, but is a bimodal star block copolymer. Figure 2 is the gel permeation chromatogram of its bimodal star block copolymer.

Comparative example 4

Comparative example 4 is a star-shaped block copolymer with a monomorphic segment reported in the patent CN1241582A. The difference from Example 1 is that the gradient temperature-controlled polymerization method is used for the synthesis of the gradient segment, and the polymerization is performed at a high temperature first, that is, the polymerization temperature of the second step is 139°C, and the mixed monomers are added at one time, and then the reaction temperature is lowered for polymerization, that is The polymerization temperature of the third step is 75° C., the mixed monomers are added at one time, and all the other conditions are the same as in Example 1.

Comparative example 5

Comparative Example 5 is a commercialized SBS-2504, which belongs to the same type of styrene-based thermoplastic elastomer as the copolymer of the present invention, but is a multimodal star triblock copolymer. Figure 3 is a gel permeation chromatogram of the multimodal star block copolymer.

Comparative example 6

Comparative Example 6 is a star-shaped block copolymer thermoplastic elastomer containing a single gradient segment, but its random gradient segment is synthesized by a temperature gradient polymerization method. Polymerize at high temperature first, that is, the polymerization temperature of step II is 150°C, and the mixed monomers are added at one time, and then lower the reaction temperature for polymerization, that is, the polymerization temperature of step III is 72°C, and the mixed monomers are added at one time, and the rest of the conditions Same as Example 6.

The test results of the physical and mechanical properties of the copolymers of Examples 1-10 and Comparative Examples 1-6 are listed in Table 3. The test of tensile strength is carried out according to GB/T528-92; the test of notched impact strength is carried out according to GB1043-93; the yield strength is tested according to GB/T528-92; the light transmittance and haze are tested according to GB3410-80; Determination by gel permeation chromatography (GPC).

Fig. 1 and Fig. 2, Fig. 3 comparative illustration, the functionalized multi-arm radial block copolymer containing a random tapered segment prepared by the method of the present invention is a single form, comparative example 2, comparative example 4 copolymer It is multi-modal (also known as multi-modal).

The comparison of the physical and mechanical properties of the polymers of Examples 1 to 5 listed in Table 3 and Comparative Examples 1 to 4 shows that the single-morph multi-arm radial block containing a random gradient segment prepared by the method of the present invention Compared with the polymers of comparative examples 1, 2 and 4, the notched impact strength and yield strength of the copolymer thermoplastic resin are all improved to varying degrees. The light transmittance of the example copolymer is close to that of the comparative example but the haze is lower than that of the comparative example. Embodiment 1～5 and comparative example 4 illustrate that the impact strength temperature gradient polymerization method copolymer of the thermoplastic resin of the present invention obtained by the random gradual change section adopts the feed speed and feed amount control polymerization method to improve about 10%, and the light transmittance has improved About 1 percentage point, the haze decreased by about 10%.

The comparison of the physical and mechanical properties of the polymers of Examples 6 to 10 listed in Table 3 and Comparative Examples 1, 5, and 6 shows that the single-morph multi-arm radial polymorph containing a random gradient segment prepared by the method of the present invention is The tensile strength, notched impact strength and yield strength of the block copolymer thermoplastic elastomers are all improved in different degrees compared with the polymers of the comparative examples. It is also a styrene-based thermoplastic elastomer. The light transmittance of the copolymers of Examples 6-10 is 10%-15% higher than that of Comparative Example 5, and the haze is about 15% lower than that of Comparative Example 5. The random gradual change section of the copolymer of the embodiment adopts the method of controlling the feeding amount and feeding speed, and the impact strength of the copolymer of the temperature gradient polymerization method of Comparative Example 6 is increased by about 10%.

Table 1 embodiment experiment raw material and auxiliary agent kind

Table 2 embodiment formula and processing condition

Table 3 embodiment, comparative example copolymer performance

Claims (18)

1. radial segmented copolymer of monomorphism that contains random graded chain segment, its structural formula is expressed as follows: R-X-[B ₃-(B ₂→ S ₃) B ₁/ S ₂-S ₁] ₃

S wherein ₁, S ₂And S ₃All represent monovinylarene, B ₁, B ₂And B ₃All represent conjugated diene; R is the saturated fatty alkyl that contains 1～6 carbon atom; X is Si, Sn; Promptly be by containing the radial segmented copolymer of monomorphism of a monovinylarene homopolymerization section, a random graded chain segment of monovinylarene-conjugated diene and a conjugated diolefin homopolymerization section in the anionic polymerization synthetic single armed molecular chain; The parts by weight of the mono vinyl arenes monomer that contains in the multipolymer are 30%～95%, the parts by weight of conjugated diene monomer are 5%～70%, the molecular weight of polymkeric substance is 160 000～220 000, the acquisition of the random graded chain segment of polymkeric substance is that the employing polymerization temperature is 65 ℃～100 ℃, initiator is once added, monovinylarene and conjugated diolefine hydrocarbon mixture add in two batches, feed rate is with the weight percent meter of mixture, be 4.6%～9.5%/min, the first batch of feed rate of mixture is lower than speed of reaction, and the remaining mixture feed rate is higher than speed of reaction.

2. the radial segmented copolymer of monomorphism according to claim 1 is characterized in that copolymer structure formula R-X-[B ₃-(B ₂-S ₃) B ₁/ S ₂-S ₁] ₃In, R is a methyl, X is Si.

3. the radial segmented copolymer of monomorphism according to claim 1, it is characterized in that mono vinyl arenes monomer is meant vinylbenzene, alpha-methyl styrene, 4-n-propylbenzene ethene, 4-phenylcyclohexane ethene, 4-dodecyl vinylbenzene, the 1-vinyl naphthalene, 2,4-dimethyl styrene, or their mixture.

4. the radial segmented copolymer of monomorphism according to claim 1 is characterized in that conjugated diene is meant 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 3-butyl-1, the 3-octadiene, 2-phenyl-1,3-butadiene, or their mixture.

5. the radial segmented copolymer of monomorphism according to claim 1, it is characterized in that the shared parts by weight of mono vinyl arenes monomer are 35%～85% in the radial segmented copolymer of monomorphism, the shared parts by weight of conjugated diene monomer are 15%～65%.

6. the preparation method of the radial segmented copolymer of the described monomorphism of claim 1, initiator is once added, monomer divides and joins paradigmatic system in certain sequence four times, after polymerization finishes, adding coupling agent again carries out linked reaction and makes, the polymerization monomer is conjugated diene and mono vinyl arenes monomer, and its order of addition(of ingredients) is as follows:

The I step: mono vinyl arenes monomer S ₁With initiator L, form S ₁-Me, wherein Me is the metal ion of initiator;

The II step: mono vinyl arenes monomer S ₂With conjugated diene monomer B ₁, form S ₁-B ₁/ S ₂-Me;

The III step: mono vinyl arenes monomer S ₃With conjugated diene monomer B ₂, form S ₁-B ₁/ S ₂(B ₂→ S ₃)-Me;

The IV step: conjugated diene monomer B ₃, form living chain P:S ₁-B ₁/ S ₂(B ₂→ S ₃)-B ₃-Me;

V step: functionalized coupling C forms: R-X-[B ₃-(B ₂→ S ₃) B ₁/ S ₂-S ₁] ₃

Form random segment S in the II step ₁-B ₁/ S ₂-Me, III form random graded chain segment S in the step ₁-B ₁/ S ₂(B ₂→ S ₃)-Me is that the employing polymerization temperature is 65 ℃～100 ℃, the feed rate of monovinylarene and conjugated diolefine hydrocarbon mixture is with the weight percent meter of mixture, be 4.6%～9.5%/min, the former is lower than speed of reaction at feed rate, and latter's feed rate is higher than speed of reaction;

In each step, when polyreaction is performed until no free monomer and exists till; Polymerization temperature is 60 ℃～120 ℃ except that III goes on foot.

7. the preparation method of the radial segmented copolymer of monomorphism according to claim 6, polymerization temperature is 65～95 ℃ to it is characterized in that going on foot in addition by III.

8. the preparation method of the radial segmented copolymer of monomorphism according to claim 6, the parts by weight that it is characterized in that monovinylarene in the multipolymer are 30%～60%, the parts by weight of conjugated diene monomer are 40%～70%, during polymerization, 12.6%～44.30% the monovinylarene that at first will account for all total monomer weights adds polymerized unit, add the polymerization of organic single-base metal initiator then, form non-resilient segment S with active alkali metal end group ₁-Me; The mixture that adds monovinylarene and conjugated diene afterwards to paradigmatic system, monovinylarene accounts for 15.7%～47.4% of all total monomer weights in the mixture, conjugated diene accounts for 32.6%～67.9% of all total monomer weights, mixture is to inject continuously, random transition synthetic feed rate is with the weight percent meter of mixture, be 4.6%～8.4%/min, wherein random section synthetic feed rate is lower than speed of reaction, transition synthetic feed rate is higher than speed of reaction, forms polymer chain S ₁-B ₁/ S ₂(B ₂→ S ₃)-Me; 2.1%～7.4% the conjugated diene that will account for all total monomer weights again adds paradigmatic system, forms polymer chain S ₁-B ₁/ S ₂(B ₂→ S ₃)-B ₃-Me; Carry out coupling with alkoxyl silicone or stannane coupling agent at last, form the radial segmented copolymer R-X-[B of monomorphism ³-(B ₂→ S ₃) B ₁/ S ₂-S ₁] ₃

9. the preparation method of the radial segmented copolymer of monomorphism according to claim 7, the parts by weight that it is characterized in that monovinylarene in the multipolymer are 35%～55%, the parts by weight of conjugated diene monomer are 45%～65%, in the polymerization, it is to account for 15.0%～40.5% of all total monomer weights that monovinylarene adds fashionable add-on separately, monovinylarene and conjugated diene mixing add fashionable, monovinylarene accounts for 18.5%～42.0% of all total monomer weights in the mixture, conjugated diene accounts for 44.7%～61.2% of all total monomer weights, and it is to account for 2.5%～6.4% of all total monomer weights that conjugated diene adds fashionable add-on separately.

10. the preparation method of the radial segmented copolymer of monomorphism according to claim 7, when it is characterized in that forming random transition polymer chain, weight percent meter with monovinylarene and conjugated diolefine hydrocarbon mixture, feed rate with 4.6%～6.5%/min adds mixture earlier, form random section, when injecting mixture 70%～85%, the feed rate of remaining mixture with 6.7%～8.4%/min added, form transition.

11. the preparation method of the radial segmented copolymer of monomorphism according to claim 6, the parts by weight that it is characterized in that monovinylarene in the multipolymer are 60%～95%, the parts by weight of conjugated diene monomer are 5%～40%, during polymerization, 17.30%～92.80% the monovinylarene that at first will account for all total monomer weights adds polymerized unit, add the polymerization of organic single-base metal initiator then, form non-resilient segment S with active alkali metal end group ₁-Me; The mixture that adds monovinylarene and conjugated diene afterwards to paradigmatic system, monovinylarene accounts for 2.20%～77.70% of all total monomer weights in the mixture, conjugated diene accounts for 1.00%～39.75% of all total monomer weights, mixture is to inject continuously, random transition synthetic feed rate is counted 5.4%～9.5%/min with the weight percent of mixture, wherein random section synthetic feed rate is lower than speed of reaction, transition synthetic feed rate is higher than speed of reaction, forms polymer chain S ₁-B ₁/ S ₂(B ₂→ S ₃)-Me; 0.25%～4.00% the conjugated diene that will account for all total monomer weights again adds paradigmatic system, forms polymer chain S ₁-B ₁/ S ₂(B ₂→ S ₃)-B ₃-Me; Carry out coupling with alkoxyl silicone or stannane coupling agent at last, form the radial segmented copolymer of monomorphism

R-X-[B ₃-(B ₂→S ₃)B ₁/S ₂-S ₁] ₃。

12. according to claim 1] preparation method of the radial segmented copolymer of described monomorphism, the parts by weight that it is characterized in that monovinylarene in the multipolymer are 70%～85%, the parts by weight of conjugated diene monomer are 15%～30%, in the polymerization, it is to account for 25.0%～74.5% of all total monomer weights that monovinylarene adds fashionable add-on separately, monovinylarene and conjugated diene mixing add fashionable, monovinylarene accounts for 10.5%～60.0% of all total monomer weights in the mixture, conjugated diene accounts for 12.0%～29.25% of all total monomer weights, and it is to account for 0.75%～3.00% of all total monomer weights that conjugated diene adds fashionable add-on separately.

13. the preparation method of the radial segmented copolymer of monomorphism according to claim 11, when it is characterized in that forming random transition polymer chain, weight percent meter with monovinylarene and conjugated diolefine hydrocarbon mixture, feed rate with 5.4%～7.8%/min adds mixture earlier, form random section, when injecting mixture 70%～85%, improve feed rate, the feed rate of remaining mixture with 7.2%～9.5%/min added, form transition.

14. preparation method according to claim 6 or the radial segmented copolymer of 8 or 11 described monomorphism, it is characterized in that initiator is organic single-lithium compound R Li, wherein R is the compound base that contains representative examples of saturated aliphatic alkyl, alicyclic alkyl, aryl or the above-mentioned group of 1～20 carbon atom.

15., it is characterized in that initiator is n-Butyl Lithium, s-butyl lithium according to the preparation method of claim 6 or the radial segmented copolymer of 8 or 11 described monomorphism.

16. the preparation method according to claim 6 or the radial segmented copolymer of 8 or 11 described monomorphism is characterized in that coupling agent can be expressed as with general formula: R-X-(OR ') ₃, wherein R is the saturated fatty alkyl that contains 1～6 carbon atom; R ' is for containing the saturated fatty alkyl of 1～4 carbon atom; X is Si, Sn.

17. the preparation method of the radial segmented copolymer of monomorphism according to claim 6 is characterized in that the monomer total amount of random graded chain segment accounts for 28.6%～61.8% of polymkeric substance total monomer weight.

18. the preparation method of the radial block copolymerization of monomorphism according to claim 6 is characterized in that the mol ratio of monovinylarene and conjugated diene is 0.2～1.5 in the random graded chain segment.

Images