Styrene-butadiene resin composition, and preparation method therefor and use thereof

Abstract

The present invention relates to a styrene-butadiene resin composition, and a preparation method therefor and a use thereof. The styrene-butadiene resin composition comprises a first styrene-butadiene block copolymer and a second styrene-butadiene block copolymer; the first styrene-butadiene block copolymer has a star-shaped structure; the second styrene-butadiene block copolymer has a linear structure; based on the total mass of the first styrene-butadiene block copolymer and the second styrene-butadiene block copolymer being 100%, the mass percentage of the styrene structural unit is 70-90%, and the mass percentage of the butadiene structural unit is 10-30%. The styrene-butadiene resin composition in the present invention has excellent hardness, high impact resistance, high elongation and high bending modulus, and has environmental stress resistance and processability.

Description

A styrene-butadiene resin composition and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of styrene-butadiene resins, in particular to a styrene-butadiene resin composition and a preparation method and application thereof. Background Art

[0002] Styrene-butadiene resin is produced by copolymerization of butadiene and styrene. Its polymer chain contains both rigid benzene ring structures and flexible butadiene segments. It is widely used in various fields such as packaging, medical devices, home appliances, high-end daily necessities and office supplies. The hardness, impact resistance, environmental stress resistance and processing performance of styrene-butadiene resin are crucial to its application.

[0003] CN104119617A discloses an impact-resistant polystyrene material and a preparation method thereof. The disclosed impact-resistant polystyrene material comprises polystyrene, styrene-butadiene rubber, sulfur, zinc oxide, stearic acid, a rubber accelerator, and a accelerator, diphenylguanidine. The disclosed impact-resistant polystyrene material not only increases the impact resistance of polystyrene and improves conversion rate, but also has the characteristics of easy processability, good performance, and low cost. However, its composition is complex and requires the use of multiple additives.

[0004] CN105331035A discloses a styrene-butadiene resin composition and a preparation method thereof. The disclosed styrene-butadiene resin composition contains a block copolymer (PS1) SBS (PS1) and a linear polystyrene PS2, wherein SBS is a styrene-butadiene-styrene block copolymer segment with a number average molecular weight of 100,000 to 400,000, PS1 is a polystyrene segment, and PS2 has a number average molecular weight of 100,000 to 800,000. However, the disclosed styrene-butadiene resin composition fails to have both impact resistance and processability.

[0005] In summary, it is crucial to develop a styrene-butadiene resin composition that has excellent hardness and high impact resistance, as well as environmental stress resistance and processing performance.

[0006] Summary of the Invention

[0007] In view of the deficiencies of the prior art, the object of the present invention is to provide a styrene-butadiene resin composition and a preparation method and application thereof, wherein the styrene-butadiene resin composition has excellent hardness and notched Izod impact strength, and has both environmental stress resistance and processing performance.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a styrene-butadiene resin composition, comprising a first styrene-butadiene block copolymer and a second styrene-butadiene block copolymer;

[0010] The first styrene-butadiene block copolymer has a star-shaped structure;

[0011] The second styrene-butadiene block copolymer has a linear structure;

[0012] Based on the total mass of the first butadiene styrene block copolymer and the second butadiene styrene block copolymer as 100%, the mass percentage of the styrene structural unit is 70%-90% (for example, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88% or 90%, etc.), and the mass percentage of the butadiene structural unit is 10%-30% (for example, 10%, 12%, 15%, 20%, 22%, 25%, 28% or 30%, etc.).

[0013] In the present invention, a first styrene butadiene block copolymer with a star-shaped structure and a second styrene butadiene block copolymer with a linear structure are compounded and coordinated to regulate the mass percentage of styrene structural units within a specific percentage range. The formed styrene butadiene resin composition has excellent hardness, high impact resistance, high elongation and high bending modulus, and has both environmental stress resistance and processing performance. The first styrene butadiene block copolymer with a star-shaped structure provides hardness and rigidity, and the second styrene butadiene block copolymer with a linear structure provides high elongation and impact resistance.

[0014] Preferably, in the first butadiene-styrene block copolymer and the second butadiene-styrene block copolymer, the mass percentage of the styrene structural unit is each independently 70%-90% (for example, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88% or 90%, etc.), and the mass percentage of the butadiene structural unit is each independently 10%-30% (for example, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28% or 30%, etc.).

[0015] Preferably, based on the total mass of the first butadiene styrene block copolymer and the second butadiene styrene block copolymer as 100%, the mass percentage of the first butadiene styrene block copolymer is 80%-95%, for example, 80%, 82%, 84%, 86%, 88%, 90%, 92% or 94%.

[0016] Preferably, based on the total mass of the first butadiene styrene block copolymer and the second butadiene styrene block copolymer as 100%, the mass percentage of the second butadiene styrene block copolymer is 5%-20%, for example, 5%, 7%, 10%, 12%, 13%, 15%, 17%, 18% or 20%, etc.

[0017] Preferably, the molecular formula of the first styrene-butadiene block copolymer comprises (St1-St2-Bd) m -X-(Bd-St2) n .

[0018] Wherein, St1 and St2 are polystyrene segments, Bd is a polybutadiene segment, X is a coupling agent, the functionality of the coupling agent is ≥3 (for example, 4, 5, 6, 7, 8, 9 or 10, etc.), m and n are integers, m ≥ 0 (for example, 0, 1, 2, 3, 4, 5, 6 or 7, etc.), and n ≥ 0 (for example, 0, 1, 2, 3, 4, 5, 6 or 7, etc.).

[0019] Preferably, the number average molecular weight of the first styrene-butadiene block copolymer is 100,000-300,000 g / mol, for example, 150,000 g / mol, 180,000 g / mol, 200,000 g / mol, 220,000 g / mol, 250,000 g / mol or 300,000 g / mol.

[0020] In the present invention, the number average molecular weight of the first styrene butadiene block copolymer is controlled to be 100,000-300,000 g / mol. The reason is that: the first styrene butadiene block copolymer accounts for a large proportion in the styrene butadiene resin composition, and its number average molecular weight affects the overall hardness and impact resistance of the styrene butadiene resin composition; if its number average molecular weight is too high, the styrene butadiene resin composition will be difficult to process, have too high hardness, and have too high rigidity, which is not conducive to production and processing; if its number average molecular weight is too low, the hardness of the styrene butadiene resin composition will be too low, the impact resistance will be reduced, and the rigidity will be too low.

[0021] Preferably, the coupling agent includes any one of tetramethoxysilane, silicon tetrachloride, tin tetrachloride or epoxy soybean oil, or a combination of at least two thereof, wherein typical but non-limiting combinations include: a combination of silicon tetrachloride and tin tetrachloride, a combination of tin tetrachloride and epoxy soybean oil, a combination of silicon tetrachloride, tin tetrachloride and epoxy soybean oil, and the like.

[0022] Preferably, the second styrene butadiene block copolymer has a number average molecular weight of 10,000-100,000 g / mol, for example, 20,000 g / mol, 30,000 g / mol, 40,000 g / mol, 50,000 g / mol, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol or 90,000 g / mol.

[0023] In the present invention, the number average molecular weight of the second styrene butadiene block copolymer is controlled to be 10,000-100,000 g / mol. The reason is that the second styrene butadiene block copolymer mainly plays the role of improving the impact resistance of the styrene butadiene resin composition, and the size of its number average molecular weight will affect the hardness and impact resistance of the styrene butadiene resin composition; if its number average molecular weight is too high, the hardness of the styrene butadiene resin composition will decrease and the rigidity will decrease; if its number average molecular weight is too low, the impact resistance of the styrene butadiene resin composition will decrease.

[0024] Preferably, the styrene-butadiene resin composition further comprises an auxiliary agent.

[0025] Preferably, the auxiliary agent includes an antioxidant and a lubricant.

[0026] Preferably, the antioxidant includes a phenolic antioxidant and / or a phosphite antioxidant. Exemplarily, the antioxidant includes but is not limited to any one of antioxidant 1076, antioxidant 1010 or antioxidant 168, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of antioxidant 1076 and antioxidant 168, a combination of antioxidant 1010 and antioxidant 168, a combination of antioxidant 1010, antioxidant 1076 and antioxidant 168, etc.

[0027] Preferably, the lubricant comprises microcrystalline wax and / or zinc stearate.

[0028] In a second aspect, the present invention provides a method for preparing the styrene-butadiene resin composition according to the first aspect, the preparation method comprising the steps of:

[0029] The first styrene butadiene block copolymer and the second styrene butadiene block copolymer are mixed to obtain the styrene butadiene resin composition.

[0030] Preferably, the preparation method of the first styrene-butadiene block copolymer comprises the following steps:

[0031] (1) A solvent, a regulator and a portion of styrene are mixed, and a portion of an initiator is added to carry out a polymerization reaction to generate a product A containing polystyrene chain segments.

[0032] (2) The product A obtained in step (1), the remaining initiator and the remaining styrene are mixed and polymerized to generate a product B containing polystyrene segments and a product C containing polystyrene segments.

[0033] (3) The product B and product C obtained in step (2) are mixed with butadiene and subjected to polymerization reaction to generate a product D containing polystyrene segments and polybutadiene segments and a product E containing polystyrene segments and polybutadiene segments.

[0034] (4) mixing the product D obtained in step (2), the product E obtained in step (2) and a coupling agent, reacting them, and adding a terminator to obtain the first butadiene-styrene block copolymer.

[0035] In the present invention, in the preparation method of the first butadiene styrene block copolymer, step (1) generates product A, whose molecular formula is St1-Li, step (2) generates product B and product C, whose molecular formulas are St1-St2-Li and St2-Li, respectively, step (3) generates product D and product E, whose molecular formulas are St1-St2-Bd-Li and St2-Bd-Li, respectively, and step (4) obtains the first butadiene styrene block copolymer, whose molecular formula is (St1-St2-Bd)m -X-(Bd-St2) n Wherein St1 and St2 are polystyrene segments with the same or different degrees of polymerization, and Bd is a polybutadiene segment.

[0036] Preferably, in step (1), the mass percentage of the styrene of the portion in the total styrene used to prepare the first butadiene-styrene block copolymer is 30%-70%, for example, 35%, 38%, 40%, 45%, 50%, 55%, 60%, 65% or 70%, etc.

[0037] Preferably, in step (1), the mass percentage of the initiator of the portion is 50%-70% of the total initiator used to prepare the first butadiene-styrene block copolymer, for example, 50%, 52%, 55%, 57%, 60%, 62%, 65%, 67% or 70%.

[0038] Preferably, the solvent includes any one of cyclohexane, n-hexane or toluene, or a combination of at least two of them.

[0039] Preferably, the regulator includes any one of tetrahydrofuran (THF), tetramethylethylenediamine or diethanol dimethyl ether, or a combination of at least two thereof.

[0040] Preferably, the initiator used in the polymerization reaction includes n-butyl lithium.

[0041] Preferably, in steps (1) and (2), the polymerization reaction is independently carried out to a conversion rate of ≥ 99%, such as 99.1%, 99.2%, 99.4%, 99.5%, 99.6%, 99.7% or 99.8%.

[0042] Preferably, in step (4), the terminator comprises any one of methanol, carbonic acid or water, or a combination of at least two thereof.

[0043] Preferably, in step (4), the reaction further includes adding an auxiliary agent and mixing.

[0044] Preferably, the polymerization reaction temperature in steps (1) to (3) is independently 50-55°C, such as 51°C, 51.5°C, 52°C, 52.5°C, 53°C, 53.5°C or 54°C.

[0045] Preferably, the polymerization reaction time is independently 20-30 min, for example, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min or 29 min.

[0046] Preferably, the preparation method of the second styrene-butadiene block copolymer comprises the following steps:

[0047] (1') A solvent, a regulator and a portion of styrene are mixed, and an initiator is added to carry out a polymerization reaction to generate a product A' containing polystyrene chain segments.

[0048] (2') The product A' obtained in (1'), part of butadiene and part of styrene are mixed and polymerized to produce a product B' containing polystyrene segments and polybutadiene segments.

[0049] (3') The product B' obtained in (2'), the remaining butadiene and part of the styrene are mixed and polymerized to obtain the product C'.

[0050] (4') The product C' obtained in (3') and the remaining styrene are mixed, subjected to polymerization reaction, and a terminator is added to obtain the second styrene-butadiene block copolymer.

[0051] In the present invention, in the preparation method of the second butadiene-styrene block copolymer, step (1') generates product A', whose molecular formula is St1'-Li, step (2') generates product B', whose molecular formula is St1'-Bd1' / St2'-Li, wherein Bd1' / St2' represents a segment of a random block of butadiene and styrene, step (3') generates product C', whose molecular formula is St1'-Bd1' / St2'-Bd2' / St3'-Li, wherein Bd2' / St3' represents a segment of a random block of butadiene and styrene, and step (4') obtains the second butadiene-styrene block copolymer, whose molecular formula is St1'-Bd1' / St2'-Bd2' / St3'-St4', wherein St1' and St4' are polystyrene segments with the same or different degrees of polymerization, and Bd1' / St2' and Bd2' / St3' are the same or different segments of a random block of butadiene and styrene.

[0052] Preferably, the solvent includes any one of cyclohexane, n-hexane or toluene, or a combination of at least two of them.

[0053] Preferably, the regulator includes any one of tetrahydrofuran (THF), tetramethylethylenediamine or diethanol dimethyl ether, or a combination of at least two thereof.

[0054] Preferably, the initiator used in the polymerization reaction includes n-butyl lithium.

[0055] Preferably, in step (1'), the polymerization reaction is independently carried out to a conversion rate of ≥99%, such as 99.1%, 99.2%, 99.4%, 99.5%, 99.6%, 99.7% or 99.8%.

[0056] Preferably, in step (1'), the mass percentage of the styrene in the total styrene used to prepare the second styrene-butadiene block copolymer is 65%-80%, for example, 65%, 67%, 69%, 70%, 72%, 74%, 76%, 78%, 79% or 80%.

[0057] Preferably, in step (2'), the mass percentage of the styrene in the total styrene used to prepare the second styrene-butadiene block copolymer is 10%-25%, for example, 10%, 12%, 14%, 16%, 18%, 19%, 20%, 22%, 24% or 25%.

[0058] Preferably, in step (2'), the mass percentage of the butadiene in the total butadiene used to prepare the second butadiene-styrene block copolymer is 40%-55%, for example, 40%, 42%, 45%, 48%, 50%, 51%, 52%, 53%, 54% or 55%.

[0059] Preferably, in step (3'), the mass percentage of the styrene in the total styrene used to prepare the second styrene-butadiene block copolymer is 5%-20%, for example, 5%, 8%, 9%, 10%, 12%, 14%, 16%, 17%, 18%, 19% or 20%.

[0060] Preferably, in step (4'), the reaction further includes adding an auxiliary agent and mixing.

[0061] Preferably, in step (4'), the terminator comprises any one of methanol, carbonic acid or water, or a combination of at least two thereof.

[0062] Preferably, the polymerization reaction temperature in steps (1') to (4') is independently 50-55°C, such as 51°C, 51.5°C, 52°C, 52.5°C, 53°C, 53.5°C or 54°C.

[0063] Preferably, the polymerization reaction time is independently 20-30 min, for example, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min or 30 min.

[0064] In a third aspect, the present invention provides a use of the styrene-butadiene resin composition as described in the first aspect in an impact-resistant product.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) The styrene-butadiene resin composition of the present invention has excellent hardness, high impact resistance, high elongation and high flexural modulus, and has both environmental stress resistance and processing performance.

[0067] (2) In the present invention, the hardness of the styrene-butadiene resin composition is between 76-87A, the flexural modulus is ≥1085MPa, and the notched Izod impact strength is 3.2kJ / m 2 The above, under the test conditions of 200 ° C / 5kg, the melt index is between 2.4-18.6 g / 10min. Preferably, the hardness of the styrene-butadiene resin composition is between 76-84A, the notched Izod impact strength is above 5.1 kJ / m2, the flexural modulus is above 1430 MPa, and the melt index is between 6.2-9.3 g / 10min under the test conditions of 200 ° C / 5kg. DETAILED DESCRIPTION

[0068] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0069] Example 1

[0070] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof, wherein the styrene-butadiene resin composition comprises a first styrene-butadiene block copolymer and a second styrene-butadiene block copolymer;

[0071] The first styrene-butadiene block copolymer has a star-shaped structure and a number average molecular weight of 200,000 g / mol;

[0072] The second styrene-butadiene block copolymer has a linear structure and a number average molecular weight of 50,000 g / mol.

[0073] The styrene-butadiene resin composition is obtained by the following preparation method, which comprises the following steps:

[0074] (S1) Preparation of the first styrene-butadiene block copolymer:

[0075] A 10 L stainless steel polymerization kettle was replaced several times with refined nitrogen. 4500 g of solvent (cyclohexane), 0.35 g of a regulator (diethanol dimethyl ether) and 800 g of styrene were added to the kettle in a nitrogen atmosphere. 13.1 mL of a mixture of n-butyl lithium and cyclohexane was added. The mass percentage of n-butyl lithium in the mixture was 20%. The polymerization reaction was carried out at 53° C. After 25 minutes, the reaction was completed. 9.4 mL of a mixture of n-butyl lithium and cyclohexane was added. The mass percentage of n-butyl lithium in the mixture was 20%. , add 400g of styrene and mix, carry out polymerization reaction, the reaction is completed after 20 minutes, add 300g of butadiene and mix, carry out polymerization reaction, the reaction is completed after 30 minutes, add 10mL of a mixture of silicon tetrachloride and cyclohexane and mix, the mass percentage of silicon tetrachloride in the mixture is 20%, react, add 0.6g of terminator (methanol), and then add 6g of antioxidant (the mass ratio of antioxidant 1076 and antioxidant 168 is 1:1) to obtain a butadiene-styrene resin glue containing the first butadiene-styrene block copolymer.

[0076] (S2) Preparation of the second styrene-butadiene block copolymer:

[0077] A 5L stainless steel polymerization kettle was replaced several times with refined nitrogen. 2000g of solvent (cyclohexane), 0.15g of a regulator (diethanol dimethyl ether) and 85.0g of styrene were added to the kettle in a nitrogen atmosphere and mixed. 2.5mL of a mixed solution of n-butyl lithium and cyclohexane was added, wherein the mass percentage of n-butyl lithium in the mixed solution was 20%. A polymerization reaction was carried out at 53°C, and the reaction was completed after 25 minutes. 16.5g of butadiene and 20.0g of styrene were added and mixed, and the polymerization reaction was completed after 30 minutes. 16.5g of butadiene and 12.8g of styrene were added and mixed, and the polymerization reaction was completed after 30 minutes. 14.3g of styrene was added and mixed, and the polymerization reaction was completed after 25 minutes. 0.2g of a terminator (methanol) was added, and then 0.8g of an antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) was added to prepare a styrene-butadiene resin glue containing a second styrene-butadiene block copolymer.

[0078] (S3) mixing the styrene-butadiene resin glue containing the first styrene-butadiene block copolymer obtained in step (S1) and the styrene-butadiene resin glue containing the second styrene-butadiene block copolymer obtained in step (S2), devolatilizing, and granulating to obtain the styrene-butadiene resin composition.

[0079] Example 2

[0080] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof, wherein the styrene-butadiene resin composition comprises a first styrene-butadiene block copolymer and a second styrene-butadiene block copolymer;

[0081] The first styrene-butadiene block copolymer has a linear structure and a number average molecular weight of 100,000 g / mol;

[0082] The second styrene-butadiene block copolymer has a star-shaped structure and a number average molecular weight of 100,000 g / mol.

[0083] The styrene-butadiene resin composition is obtained by the following preparation method, which comprises the following steps:

[0084] (S1) Preparation of the first styrene-butadiene block copolymer:

[0085] A 10 L stainless steel polymerization kettle was replaced several times with refined nitrogen. 4500 g of solvent (cyclohexane), 0.35 g of regulator (tetramethylethylenediamine) and 552 g of styrene were added to the kettle in a nitrogen atmosphere. 20.6 mL of a mixture of n-butyl lithium and cyclohexane was added. The mass percentage of n-butyl lithium in the mixture was 20%. The polymerization reaction was carried out at 53° C. After 25 minutes, the reaction was completed. 11.8 mL of a mixture of n-butyl lithium and cyclohexane was added. The mass percentage of n-butyl lithium in the mixture was 20%. 498g of styrene was mixed and polymerization reaction was carried out. After 20 minutes, 450g of butadiene was added and mixed, and polymerization reaction was carried out. After 30 minutes, 15mL of a mixture of silicon tetrachloride and cyclohexane was added and mixed. The mass percentage of silicon tetrachloride in the mixture was 20%. The mixture was reacted, 0.6g of terminator (water) was added, and then 6g of antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) and 1.5g of microcrystalline wax were added to obtain a butadiene-styrene resin glue containing the first butadiene-styrene block copolymer.

[0086] (S2) Preparation of the second styrene-butadiene block copolymer:

[0087] A 5L stainless steel polymerization kettle was replaced several times with refined nitrogen. 2000g of solvent (cyclohexane), 0.15g of a regulator (tetramethylethylenediamine) and 196g of styrene were added to the kettle in a nitrogen atmosphere and mixed. 2.7mL of a mixture of n-butyllithium and cyclohexane was added, wherein the mass percentage of n-butyllithium in the mixture was 20%. A polymerization reaction was carried out at 53°C, and the reaction was completed after 25 minutes. 60g of butadiene and 28g of styrene were added and mixed, and the polymerization reaction was completed after 30 minutes. 52.5g of butadiene and 18g of styrene were added and mixed, and the polymerization reaction was completed after 30 minutes. 20.5g of styrene was added and mixed, and the polymerization reaction was completed after 25 minutes. 0.2g of a terminator (water) was added, and then 0.8g of an antioxidant (the mass ratio of antioxidant 1076 to antioxidant 168 was 1:1) and 0.2g of microcrystalline wax were added to form a butadiene-styrene resin glue containing a second butadiene-styrene block copolymer.

[0088] (S3) mixing the styrene-butadiene resin glue containing the first styrene-butadiene block copolymer obtained in step (S1) and the styrene-butadiene resin glue containing the second styrene-butadiene block copolymer obtained in step (S2), devolatilizing, and granulating to obtain the styrene-butadiene resin composition.

[0089] Example 3

[0090] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof, wherein the styrene-butadiene resin composition comprises a first styrene-butadiene block copolymer and a second styrene-butadiene block copolymer;

[0091] The first styrene-butadiene block copolymer has a linear structure and a number average molecular weight of 300,000 g / mol;

[0092] The second styrene-butadiene block copolymer has a star-shaped structure and a number average molecular weight of 10,000 g / mol.

[0093] The styrene-butadiene resin composition is obtained by the following preparation method, which comprises the following steps:

[0094] (S1) Preparation of the first styrene-butadiene block copolymer:

[0095] A 10 L stainless steel polymerization kettle was replaced several times with refined nitrogen. In a nitrogen atmosphere, 4500 g of solvent (toluene), 0.35 g of regulator (tetrahydrofuran) and 810 g of styrene were added to the kettle. 7.8 mL of a mixed solution of n-butyl lithium and cyclohexane was added. The mass percentage of n-butyl lithium in the mixed solution was 20%. The polymerization reaction was carried out at 53 ° C. After 25 minutes, the reaction was completed. 7 mL of a mixed solution of n-butyl lithium and cyclohexane was added. The mass percentage of n-butyl lithium in the mixed solution was 20%. 540 g of styrene was added. The mixture was stirred for 2 hours, and the mixture was stirred for 3 hours. The mixture was stirred for 2 hours. The mixture was stirred for 3 ...

[0096] (S2) Preparation of the second styrene-butadiene block copolymer:

[0097] A 5L stainless steel polymerization kettle was replaced several times with refined nitrogen. In a nitrogen atmosphere, 2000g of solvent (toluene), 0.15g of a regulator (tetrahydrofuran) and 44.2g of styrene were added to the kettle and mixed. 4.5mL of a mixture of n-butyl lithium and cyclohexane was added, wherein the mass percentage of n-butyl lithium in the mixture was 20%. A polymerization reaction was carried out at 50°C, and the reaction was completed after 25 minutes. 4g of butadiene and 10.8g of styrene were added and mixed, and a polymerization reaction was carried out. The reaction was completed after 30 minutes. 4g of butadiene and 10.8g of styrene were added and mixed, and a polymerization reaction was carried out. The reaction was completed after 30 minutes. 6.2g of styrene was added and mixed, and a polymerization reaction was carried out. The reaction was completed after 25 minutes. 0.2g of a terminator (carbonic acid) was added, and then 0.7g of an antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) and 0.1g of zinc stearate were added to form a butadiene-styrene resin glue containing a second butadiene-styrene block copolymer.

[0098] (S3) mixing the styrene-butadiene resin glue containing the first styrene-butadiene block copolymer obtained in step (S1) and the styrene-butadiene resin glue containing the second styrene-butadiene block copolymer obtained in step (S2), devolatilizing, and granulating to obtain the styrene-butadiene resin composition.

[0099] Example 4

[0100] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the number average molecular weight of the first styrene-butadiene block copolymer is 50,000 g / mol. To prepare the styrene-butadiene resin composition, the preparation method of the first styrene-butadiene block copolymer is adjusted as follows:

[0101] (S1) Preparation of the first styrene-butadiene block copolymer: a 10 L stainless steel polymerization kettle was replaced several times with refined nitrogen, 4500 g of solvent (cyclohexane), 0.35 g of a regulator (diethanol dimethyl ether) and 800 g of styrene were added to the kettle in a nitrogen atmosphere, 22.3 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 20%, and polymerization was carried out at 53° C. After 25 minutes, the reaction was completed, and 24.6 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 20%. The mass percentage of 20% and 400g of styrene are mixed and polymerization reaction is carried out. The reaction is completed after 20 minutes. 300g of butadiene is added and mixed, and polymerization reaction is completed after 30 minutes. 17.2mL of a mixture of silicon tetrachloride and cyclohexane is added and mixed. The mass percentage of silicon tetrachloride in the mixture is 20%. The mixture is reacted, 0.6g of a terminator (methanol) is added, and then 6g of an antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) is added to obtain a butadiene-styrene resin glue containing the first butadiene-styrene block copolymer.

[0102] The rest are the same as in Example 1.

[0103] Example 5

[0104] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof. The difference between this embodiment and Example 1 is that the number average molecular weight of the first styrene-butadiene block copolymer is 350,000 g / mol. To prepare the styrene-butadiene resin composition, the preparation method of the first styrene-butadiene block copolymer is adjusted as follows:

[0105] (S1) Preparation of the first styrene-butadiene block copolymer: a 10 L stainless steel polymerization kettle was replaced several times with refined nitrogen, 4500 g of solvent (cyclohexane), 0.35 g of a regulator (diethanol dimethyl ether) and 800 g of styrene were added to the kettle in a nitrogen atmosphere, 4.3 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 20%, and polymerization was carried out at 53° C. After 25 minutes, the reaction was complete, and 7.6 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 20%. The percentage is 20%, 400g of styrene is added and mixed, and a polymerization reaction is carried out. After 20 minutes, the reaction is completed, 300g of butadiene is added and mixed, and a polymerization reaction is carried out. After 30 minutes, the reaction is completed, 7.2mL of a mixture of silicon tetrachloride and cyclohexane is added and mixed, the mass percentage of silicon tetrachloride in the mixture is 20%, and the reaction is carried out. 0.5g of a terminator (methanol) is added, and then 6g of an antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) is added to obtain a butadiene-styrene resin glue containing the first butadiene-styrene block copolymer.

[0106] The rest are the same as in Example 1.

[0107] Example 6

[0108] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof. The difference between this embodiment and Example 1 is that the number average molecular weight of the second styrene-butadiene block copolymer is 5000 g / mol. To prepare the styrene-butadiene resin composition, the preparation method of the second styrene-butadiene block copolymer is adjusted as follows:

[0109] (S2) Preparation of the second styrene-butadiene block copolymer: A 5 L stainless steel polymerization kettle was replaced with purified nitrogen several times. 2000 g of solvent (cyclohexane), 0.15 g of a regulator (diethanol dimethyl ether), and 85.0 g of styrene were added to the kettle in a nitrogen atmosphere. 22.5 mL of a mixture of n-butyl lithium and cyclohexane was added, wherein the mass percentage of n-butyl lithium in the mixture was 20%. The polymerization reaction was carried out at 53° C. After 25 minutes, the reaction was complete. 16.5 g of butadiene and 20. 0g styrene is mixed and polymerization reaction is carried out. After 30 minutes, the reaction is completed. 16.5g butadiene and 12.8g styrene are added and mixed. The polymerization reaction is completed after 30 minutes. 14.3g styrene is added and mixed. The polymerization reaction is completed after 25 minutes. 0.2g terminator (methanol) is added, and then 0.8g antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) is added to form a butadiene-styrene resin glue containing a second butadiene-styrene block copolymer.

[0110] The rest are the same as in Example 1.

[0111] Example 7

[0112] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the number average molecular weight of the second styrene-butadiene block copolymer is 120,000 g / mol. To prepare the styrene-butadiene resin composition, the preparation method of the second styrene-butadiene block copolymer is adjusted as follows:

[0113] (S2) Preparation of a second styrene-butadiene block copolymer: A 5 L stainless steel polymerization kettle was replaced several times with refined nitrogen. 2000 g of solvent (cyclohexane), 0.15 g of a regulator (diethanol dimethyl ether), and 85.0 g of styrene were added to the kettle in a nitrogen atmosphere and mixed. 1.2 mL of a mixture of n-butyl lithium and cyclohexane was added, wherein the mass percentage of n-butyl lithium in the mixture was 20%. A polymerization reaction was carried out at 53° C. After 25 minutes, the reaction was complete. 16.5 g of butadiene and 20.0 g of styrene were added and mixed, and a polymerization reaction was carried out. After 30 minutes, the reaction was complete. 16.5 g of butadiene and 12.8 g of styrene were added and mixed, and a polymerization reaction was carried out. After 30 minutes, the reaction was completed, 14.3g of styrene was added and mixed to carry out polymerization reaction. After 25 minutes, the reaction was completed, 0.2g of terminator (methanol) was added, and then 0.8g of antioxidant (antioxidant 1076 and antioxidant 168 with a mass ratio of 1:1) was added to form a styrene-butadiene resin glue containing a second styrene-butadiene block copolymer.

[0114] The rest are the same as in Example 1.

[0115] Example 8

[0116] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the mass percentage of the styrene structural unit in the first styrene-butadiene block copolymer is 55%. To prepare the styrene-butadiene resin composition, the preparation method of the first styrene-butadiene block copolymer is adjusted as follows:

[0117] (S1) Preparation of the first styrene-butadiene block copolymer: a 10 L stainless steel polymerization kettle was replaced with refined nitrogen several times, 4500 g of solvent (cyclohexane), 0.35 g of regulator (diethanol dimethyl ether) and 700 g of styrene were added to the kettle in a nitrogen atmosphere, 13.1 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 20%, and polymerization was carried out at 53°C. After 25 minutes, the reaction was completed, and 9.4 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 10.5%. The mass percentage of the mixture was 20%, 125 g of styrene was added and mixed, and a polymerization reaction was carried out. After 20 minutes, the reaction was completed. 675 g of butadiene was added and mixed, and a polymerization reaction was carried out. After 30 minutes, the reaction was completed. 10 mL of a mixture of silicon tetrachloride and cyclohexane was added and mixed. The mass percentage of silicon tetrachloride in the mixture was 20%. The mixture was reacted, 0.6 g of a terminator (methanol) was added, and then 6 g of an antioxidant (the mass ratio of antioxidant 1076 to antioxidant 168 was 1:1) was added to obtain a butadiene-styrene resin glue containing the first butadiene-styrene block copolymer.

[0118] The rest are the same as in Example 1.

[0119] Example 9

[0120] This embodiment provides a styrene-butadiene resin composition and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the mass percentage of the styrene structural unit in the first styrene-butadiene block copolymer is 95%. To prepare the styrene-butadiene resin composition, the preparation method of the first styrene-butadiene block copolymer is adjusted as follows:

[0121] (S1) Preparation of the first styrene-butadiene block copolymer: a 10 L stainless steel polymerization kettle was replaced several times with refined nitrogen, 4500 g of solvent (cyclohexane), 0.35 g of regulator (diethanol dimethyl ether) and 800 g of styrene were added to the kettle in a nitrogen atmosphere, 13.1 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 20%, and polymerization was carried out at 53°C. After 25 minutes, the reaction was completed, and 9.4 mL of a mixture of n-butyl lithium and cyclohexane was added, the mass percentage of n-butyl lithium in the mixture was 10.5%. The mixture was stirred for 20 minutes (the weight percentage was 20%), 625 g of styrene was added and mixed, and a polymerization reaction was carried out. After 20 minutes, the reaction was completed. 75 g of butadiene was added and mixed, and a polymerization reaction was carried out. After 30 minutes, 10 mL of a mixture of silicon tetrachloride and cyclohexane was added and mixed, and the weight percentage of silicon tetrachloride in the mixture was 20%), and the mixture was reacted. 0.6 g of a terminator (methanol) was added, and then 6 g of an antioxidant (antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1) was added to obtain a butadiene-styrene resin glue containing the first butadiene-styrene block copolymer.

[0122] The rest are the same as in Example 1.

[0123] Comparative Example 1

[0124] This comparative example provides a butadiene-styrene resin composition and a preparation method thereof. The difference between the comparative example and Example 1 is that the butadiene-styrene resin composition does not include a first butadiene-styrene block copolymer, and the rest is the same as Example 1.

[0125] Comparative Example 2

[0126] This comparative example provides a butadiene-styrene resin composition and a preparation method thereof. The difference between the comparative example and Example 1 is that the butadiene-styrene resin composition does not include a second butadiene-styrene block copolymer, and the rest is the same as Example 1.

[0127] Performance Testing

[0128] The styrene-butadiene resin compositions described in Examples 1-9 and Comparative Examples 1-2 were tested as follows:

[0129] (1) Hardness: The indentation hardness (Shore hardness) was measured using a durometer in accordance with GB / T 2411-2008 Plastics and Hard Rubber.

[0130] (2) Notched Izod impact strength: in accordance with GB / T 1843-2008 Determination of Izod impact strength of plastics.

[0131] (3) Flexural modulus: in accordance with GB / T 9341-2008 Determination of flexural properties of plastics.

[0132] (4) Melt index (200°C / 5kg): Determination of melt mass flow rate (MFR) and melt volume flow rate (MVR) in accordance with GB / T 3682.1-2018 Plastics Thermoplastics.

[0133] The test results are summarized in Table 1.

[0134] Table 1

[0135] According to the data in Table 1, the hardness of the styrene-butadiene resin composition of the present invention is between 76-87A, and the notched Izod impact strength is between 3.2kJ / m 2 The flexural modulus is above 1085 MPa, and the melt index is between 2.4-18.6 g / 10 min under the test conditions of 200 ° C / 5 kg; the hardness of the styrene-butadiene resin composition provided in Examples 1-3 is between 76-84A, and the notched Izod impact strength is 5.1 kJ / m 2 The above, the flexural modulus is above 1430 MPa, and the melt index is between 6.2-9.3 g / 10 min under the test conditions of 200 ° C / 5 kg. The styrene-butadiene resin composition of the present invention has excellent hardness and notched Izod impact strength, and has both environmental stress resistance and processing performance.

[0136] Analysis of Comparative Examples 1-2 and Example 1 shows that if the first styrene butadiene block copolymer is not added to the styrene butadiene resin composition (Comparative Example 1), the hardness and flexural modulus decrease; if the second styrene butadiene block copolymer is not added to the styrene butadiene resin composition (Comparative Example 2), the notched Izod impact strength decreases, demonstrating that the styrene butadiene resin composition formed by the synergistic combination of the first styrene butadiene block copolymer and the second styrene butadiene block copolymer of the present invention has better performance.

[0137] Analysis of Examples 4-5 and Example 1 shows that if the number average molecular weight of the first styrene butadiene block copolymer is low (Example 4), the notched Izod impact strength and flexural modulus are reduced; if the number average molecular weight of the first styrene butadiene block copolymer is high (Example 5), the styrene butadiene resin composition has high hardness and low melt index, which is not conducive to production and processing. This proves that the number average molecular weight of the first styrene butadiene block copolymer is 100,000-300,000 g / mol, and the resulting styrene butadiene resin composition has better performance.

[0138] Analysis of Examples 6-7 and Example 1 shows that if the number average molecular weight of the second styrene butadiene block copolymer is low (Example 6), the notched Izod impact strength is low, and if the number average molecular weight of the second styrene butadiene block copolymer is high (Example 7), the flexural modulus is low, which proves that the number average molecular weight of the second styrene butadiene block copolymer is 10,000-100,000 g / mol, and the formed styrene butadiene resin composition has better performance.

[0139] Analysis of Examples 8-9 and Example 1 shows that if the mass percentage of the styrene structural unit in the first butadiene styrene block copolymer is on the low side (Example 8), the hardness is low; if the mass percentage of the styrene structural unit in the first butadiene styrene block copolymer is on the high side (Example 9), the notched cantilever beam impact strength is low, which proves that the first butadiene styrene block copolymer and the second butadiene styrene block copolymer formed by the styrene structural units in a specific ratio cooperate with each other to form a butadiene styrene resin composition with better performance.

[0140] While the present invention is described through the above-described embodiments, the present invention is not limited to the above-described detailed methods, nor does it necessarily rely on the above-described detailed methods for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A styrene-butadiene resin composition, characterized in that The styrene-butadiene resin composition comprises a first styrene-butadiene block copolymer and a second styrene-butadiene block copolymer; The first styrene-butadiene block copolymer has a star-shaped structure; The second styrene-butadiene block copolymer has a linear structure; Taking the total mass of the first butadiene styrene block copolymer and the second butadiene styrene block copolymer as 100%, the mass percentage of the styrene structural unit is 70%-90%, and the mass percentage of the butadiene structural unit is 10%-30%.

2. The styrene-butadiene resin composition according to claim 1, characterized in that In the first butadiene-styrene block copolymer and the second butadiene-styrene block copolymer, the mass percentage of the styrene structural unit is independently 70%-90%, and the mass percentage of the butadiene structural unit is independently 10%-30%.

3. The styrene-butadiene resin composition according to claim 1 or 2, characterized in that Taking the total mass of the first styrene butadiene block copolymer and the second styrene butadiene block copolymer as 100%, the mass percentage of the first styrene butadiene block copolymer is 80%-95%; Preferably, based on the total mass of the first butadiene styrene block copolymer and the second butadiene styrene block copolymer being 100%, the mass percentage of the second butadiene styrene block copolymer is 5%-20%.

4. The styrene-butadiene resin composition according to any one of claims 1 to 3, characterized in that The molecular formula of the first styrene-butadiene block copolymer includes (St1-St2-Bd) m -X-(Bd-St2) n , Wherein, St1 and St2 are polystyrene segments, Bd is a polybutadiene segment, X is a coupling agent, the functionality of the coupling agent is ≥3, m and n are integers, m≥0, n≥0; Preferably, the number average molecular weight of the first butadiene-styrene block copolymer is 100,000-300,000 g / mol; Preferably, the coupling agent includes any one or a combination of at least two of tetramethoxysilane, silicon tetrachloride, tin tetrachloride or epoxidized soybean oil; Preferably, the number average molecular weight of the second butadiene-styrene block copolymer is 10,000-100,000 g / mol.

5. The styrene-butadiene resin composition according to any one of claims 1 to 4, characterized in that The styrene-butadiene resin composition further comprises an auxiliary agent; Preferably, the auxiliary agent includes an antioxidant and a lubricant; Preferably, the lubricant comprises microcrystalline wax and / or zinc stearate.

6. A method for preparing the styrene-butadiene resin composition according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: The first styrene butadiene block copolymer and the second styrene butadiene block copolymer are mixed to obtain the styrene butadiene resin composition.

7. The preparation method according to claim 6, characterized in that: The preparation method of the first styrene-butadiene block copolymer comprises the following steps: (1) mixing a solvent, a regulator and a portion of styrene, adding a portion of an initiator to carry out a polymerization reaction, and generating a product A containing a polystyrene chain segment; (2) mixing the product A obtained in step (1), the remaining initiator and the remaining styrene, and performing a polymerization reaction to generate a product B containing a polystyrene chain segment and a product C containing a polystyrene chain segment; (3) mixing the product B and product C obtained in step (2) with butadiene, and performing a polymerization reaction to generate a product D containing polystyrene segments and polybutadiene segments, and a product E containing polystyrene segments and polybutadiene segments; (4) mixing the product D obtained in step (2), the product E obtained in step (2) and a coupling agent, reacting them, and adding a terminator to obtain the first butadiene-styrene block copolymer.

8. The preparation method according to claim 6 or 7, characterized in that: In step (1), the mass percentage of the styrene in the whole styrene used to prepare the first styrene-butadiene block copolymer is 30%-70%; Preferably, in step (1), the part of the initiator used in preparing the first butadiene styrene block copolymer The mass percentage of all initiators used is 50%-70%; Preferably, the solvent comprises any one of cyclohexane, n-hexane or toluene, or a combination of at least two thereof; Preferably, the regulator comprises any one of tetrahydrofuran, tetramethylethylenediamine or diethanol dimethyl ether or a combination of at least two thereof; Preferably, the initiator used in the polymerization reaction includes n-butyl lithium; Preferably, in steps (1) and (2), the polymerization reaction is independently carried out to a conversion rate of ≥ 99%; Preferably, in step (4), the terminator comprises any one or a combination of at least two of methanol, carbonic acid or water; Preferably, in step (4), the reaction further includes adding an auxiliary agent and mixing.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The preparation method of the second styrene-butadiene block copolymer comprises the following steps: (1') mixing a solvent, a regulator and a portion of styrene, adding an initiator to carry out a polymerization reaction, and generating a product A' containing a polystyrene chain segment; (2') mixing the product A' obtained in (1'), part of butadiene and part of styrene, and subjecting them to a polymerization reaction to generate a product B' containing polystyrene segments and polybutadiene segments; (3') mixing the product B' obtained in (2'), the remaining butadiene and part of the styrene, and performing a polymerization reaction to obtain a product C'; (4') mixing the product C' obtained in (3') and the remaining styrene, performing a polymerization reaction, and adding a terminator to obtain the second styrene-butadiene block copolymer; Preferably, in step (1'), the mass percentage of the styrene in the whole styrene used to prepare the second styrene-butadiene block copolymer is 60%-80%; Preferably, in step (2'), the part of styrene used in preparing the second styrene-butadiene block copolymer The mass percentage of all styrene used is 10%-20%; Preferably, in step (2'), the mass percentage of the portion of butadiene in the total butadiene used to prepare the second butadiene-styrene block copolymer is 40%-55%; Preferably, in step (3'), the mass percentage of the styrene in the whole styrene used to prepare the second styrene-butadiene block copolymer is 5%-20%; Preferably, in step (4'), the reaction further comprises adding an auxiliary agent and mixing.

10. Use of the styrene-butadiene resin composition according to any one of claims 1 to 5 in impact-resistant products.

Images