Polyhydroxy conjugated olefin polymer and preparation method thereof

Abstract

The invention discloses a polyhydroxy conjugated olefin polymer and a preparation method thereof. The structural formula of the polyhydroxy conjugated olefin polymer is (I) or (II): # imgabs0 # (I) and # imgabs1 # (II), in the general formula (I), R1 is-C4H9,-C2H5O,-C3H7O or-C9H19O4; r2 is-H or-CH3; r < 3 > is-C < 6 > H5 or-C < 8 > H7; r < 4 > is C < 4 > H < 9 >, C < 2 > H < 5 > O, C < 3 > H < 7 > O or C < 9 > H < 19 > O < 4 >; m is equal to 0-200, n is equal to 0-200, x is equal to 0-200, y is equal to 1-10, and m, n and x are not 0 at the same time; in the formulas (I) and (II), at least one of R1 and R4 is-C9H19O4. The polyhydroxy-terminated conjugated olefin polymer or the polyhydroxy-terminated conjugated olefin polymer with hydroxyl groups distributed in a molecular chain is directly obtained through one-pot polymerization and end capping, the process is simple, the preparation cost is low, the method is suitable for various anionic initiators, the functionality of the synthesized polyhydroxy conjugated olefin polymer is adjustable, and the method is suitable for industrial production. And the curing speed and the mechanical property of the polyurethane are greatly improved when the polyurethane is prepared by reacting with isocyanate.

Description

Technical Field

[0001] The invention relates to the technical field of liquid rubber in polymer materials, in particular to a polyhydroxy conjugated olefin polymer and a preparation method thereof. Background Art

[0002] Since the last century, hydroxy-terminated conjugated olefin polymers represented by hydroxy-terminated polybutadiene (HTPB) and hydroxy-terminated butadiene-styrene copolymer (HTBS) are a class of "telechelic" polymer compounds with active terminal hydroxyl groups. They have good physical and chemical properties, mechanical properties and processability, and are widely used in polyurethane materials, adhesives, coatings, insulating materials and other fields.

[0003] There are two major methods for synthesizing terminal hydroxyl conjugated olefin polymers: free radical polymerization and anionic polymerization. Among them, free radical method terminal hydroxyl conjugated olefin polymers have low cost and high functionality (>2.0). When used as adhesives, they cure faster, so they are more widely used, but their molecular weight distribution index is wide, viscosity is high, and the microstructure is difficult to adjust. Relatively speaking, anionic method terminal hydroxyl conjugated olefin polymers have the characteristics of narrow molecular weight distribution index and adjustable microstructure, and the hydroxyl functional groups are distributed at both ends of the molecular chain. When used in polyurethane materials, they can effectively improve the storage stability and elongation of the material. However, during the anionic polymerization process, due to the initiator deactivation caused by moisture and impurities in the raw materials, side reactions, etc., the terminal hydroxyl conjugated olefin polymers prepared by the anionic method usually have a low functionality (≤1.9), so the anionic method terminal hydroxyl conjugated olefin polymers are difficult to form a cross-linked network structure during use as an adhesive, which leads to the long curing time required for the preparation of polyurethane and the low tensile strength of the product.

[0004] In order to increase the hydroxyl functionality of conjugated olefin polymers, patents CN114195938A and CN115895579A use peroxide to initiate copolymerization of butadiene and acrylate, and obtain a series of multifunctional hydroxyl-terminated liquid rubbers after hydrolysis; patent CN109251273B discloses a method for synthesizing polyhydroxyl polybutadiene by grafting isopentenol with hydroxyl-terminated polybutadiene under oxidative conditions; patents CN105601770A and CN107663256A report a class of synthetic methods for preparing polyhydroxyl polybutadiene by ring opening of epoxidized polybutadiene. However, in these schemes, the hydroxyl groups are irregularly distributed in the middle of the molecular chain, which greatly changes the chemical structure of the hydroxyl-terminated conjugated olefin polymer and seriously affects the mechanical properties of the corresponding elongation at break, tensile strength, elastic modulus, etc.

[0005] In order to realize the synthesis of terminal polyhydroxy conjugated olefin polymers, Wang Xiangmei et al. of North University of China (Experimental Study on the Synthesis of Polyhydroxy Polybutadiene from Terminal Hydroxyl Polybutadiene / Epichlorohydrin, Polymer Bulletin, 2017, 4: 63-71) disclosed a polyhydroxy polybutadiene and its synthesis method, which uses terminal hydroxy polybutadiene as raw material, and reacts with epichlorohydrin and sodium hydroxide to produce Williams ether synthesis reaction under the catalysis of tetrabutylammonium bromide to obtain terminal epoxy polybutadiene, which is then hydrolyzed to obtain terminal polyhydroxy polybutadiene. Patent CN107446074B uses the method of active cationic ring-opening polymerization, using boron trifluoride ether complex as a catalyst to introduce 3-hydroxymethyl-3-methyloxetane to both ends of terminal hydroxy polybutadiene to form terminal polyhydroxy polybutadiene. Although the above two methods can prepare terminal polyhydroxy conjugated olefin polymers, they both require terminal hydroxy conjugated olefin finished products as reaction raw materials and cannot be synthesized in one step. In addition, tetrabutylammonium bromide and boron trifluoride ether complex are prone to emulsification and are difficult to remove by conventional water washing post-treatment, which greatly increases the production cost. Summary of the invention

[0006] The purpose of the present invention is to disclose a polyhydroxy conjugated olefin polymer and a preparation method thereof, wherein the polyhydroxy conjugated olefin polymer can increase the number of hydroxyl groups of the hydroxy conjugated olefin polymer liquid rubber, improve the curing speed when the hydroxy conjugated olefin polymer reacts with isocyanate compounds, increase the tensile strength and elongation, and improve the mechanical properties of the polyurethane elastomer. Compared with the existing terminal hydroxy conjugated olefin polymer, the present invention does not change the main structure of the terminal hydroxy conjugated olefin polymer, can directly obtain the terminal polyhydroxy conjugated olefin polymer or the terminal polyhydroxy conjugated olefin polymer with hydroxyl groups distributed in the molecular chain through polymerization and end-capping in one pot, has a simple process and low preparation cost.

[0007] To achieve the above object, the first aspect of the present invention provides a polyhydroxy conjugated olefin polymer, wherein the polyhydroxy conjugated olefin polymer has the structural formula (I) or (II): (I) (II); Wherein, R1 is -C4H9, -C2H5O, -C3H7O or -C9H 19 O4; R2 is -H or -CH3; R3 is -C6H5 or -C8H7; R4 is C4H9, -C2H5O, -C3H7O or -C9H 19 O4; m = 0 ~ 200, n = 0 ~ 200, x = 0 ~ 200, y = 1 ~ 10, and m, n, x are not 0 at the same time; In formula (I) and (II), at least one of R1 and R4 is -C9H 19 O4.

[0008] Preferably, the molecular weight of the polyhydroxy conjugated olefin polymer is preferably 2000-8000.

[0009] The second aspect of the present invention provides a method for preparing a polyhydroxy conjugated olefin polymer, comprising the following steps: (1) Under the protection of inert gas, add anionic initiator and solvent into the reactor, stir evenly and heat to the reaction temperature; (2) adding a conjugated olefin monomer at a reaction temperature to carry out free radical solution polymerization; (3) After the polymerization is completed, a capping agent is added to carry out a capping reaction; (4) After the end-capping is completed, a terminator is added to terminate the reaction, and the reaction solution is treated by acid washing, water washing, and drying to obtain a polyhydroxy conjugated olefin polymer; The end-capping agent is an epoxy end-capping agent A, or the end-capping agent is a mixture of an epoxy end-capping agent A and an epoxy end-capping agent B; The epoxy end-capping agent A is 3-ethyl-3-[(oxiranyl-2-methoxy)methyl]-oxetane, and the structure is shown below: ; The epoxy capping agent B is one of ethylene oxide and propylene oxide or a mixture of the two.

[0010] Preferably, the epoxy capping agent A is 3-ethyl-3-[(oxiran-2-methoxy)methyl]-oxetane; and the epoxy capping agent B is preferably ethylene oxide.

[0011] In step (3), depending on the type, amount and addition method of the end-capping agent, the polyhydroxy conjugated olefin polymer obtained by the reaction includes the following types: (a) The end-capping agent is an epoxy end-capping agent A, which is added at one time, and the amount of epoxy end-capping agent A is 200 mol% or more of the amount of the monolithium anion initiator, or 400 mol% or more of the amount of the dilithium anion initiator. That is, the epoxy end-capping agent A is excessive, and a single-terminal polyhydroxy conjugated olefin polymer with a functionality close to 3 or a double-terminal polyhydroxy conjugated olefin polymer with a functionality close to 6 can be prepared.

[0012] (b) The end-capping agents are epoxy end-capping agent A and epoxy end-capping agent B, which are added simultaneously, wherein the amount of epoxy end-capping agent A is 5-50 mol% of the amount of the monolithium anion initiator, or 10-100 mol% of the amount of the dilithium anion initiator; and the amount of epoxy end-capping agent B is 100-200 mol% of the amount of the monolithium anion initiator, or the molar ratio of the dilithium anion initiator is 200-400 mol%. That is, the epoxy end-capping agent A is not excessive, and the epoxy end-capping agent B is excessive, and a single-terminal polyhydroxy conjugated olefin polymer with a functionality of 1-2 or a double-terminal polyhydroxy conjugated olefin polymer with a functionality of 2-4 can be prepared.

[0013] (c) The epoxy end-capping agent A is added in batches: ① first add 10-100 mol% of the epoxy end-capping agent A in an amount equivalent to the dilithium anion initiator, and keep it at the reaction temperature for 1-3 h; ② add 400 mol% of the epoxy end-capping agent A in an amount equivalent to the dilithium anion initiator, or add 10-100 mol% of the epoxy end-capping agent A in an amount equivalent to the dilithium anion initiator and 200-400 mol% of the epoxy end-capping agent B in an amount equivalent to the dilithium anion initiator at the same time; a double-terminated polyhydroxy conjugated olefin polymer with hydroxyl groups having a functionality close to 6 or a functionality of 2-4 distributed in the molecular chain can be obtained.

[0014] The anionic initiator is a monolithium initiator and / or a dilithium initiator. The monolithium initiator is selected from one or more of n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and tert-butyl dimethylsiloxypropyl lithium; the dilithium initiator is selected from one or more of 1,4-dilithium butane initiator, 1,5-dilithium pentane initiator, 1,6-dilithium hexane initiator, dilithium divinylbenzene initiator, dilithium isoprene oligomer initiator, dilithium butadiene oligomer initiator, and dilithium styrene oligomer initiator. Preferably, the initiator is added in the form of a solution of the initiator, and the solution is consistent with the solvent.

[0015] The solvent is one or more of diethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, n-pentane, n-hexane, n-heptane, and cyclohexane, preferably a mixture of one or more of diethyl ether, tetrahydrofuran, n-hexane, and cyclohexane.

[0016] The conjugated olefin monomer is one or a mixture of butadiene, isoprene, styrene and divinylbenzene, preferably one or a mixture of two of butadiene, isoprene and styrene.

[0017] The terminator is one of water, methanol, ethanol, propanol, isopropanol or a mixture of several thereof, preferably ethanol.

[0018] The polymerization reaction temperature is -20~80°C, preferably 0~60°C; the polymerization reaction time is 1~12 h, preferably 1~4 h.

[0019] The end-capping reaction temperature is 30-80°C, preferably 50-70°C; the end-capping reaction time is 1-6 h, preferably 2-3 h.

[0020] Step (4) is to add a terminator to terminate the end-capping reaction, cool the reaction mixture, and then wash the reaction mixture with acid, water, and dry the reaction mixture to obtain the corresponding end-polyhydroxy conjugated olefin polymer liquid rubber. The acid used for the acid washing can be selected from one or more of hydrochloric acid and sulfuric acid, and the amount used is 400-1000 mol% of the amount of the initiator, and the acid washing time is 1-6 h; the drying temperature is preferably 80-130 °C, and the drying time is 1-3 h.

[0021] Compared with the existing polyhydroxy conjugated olefin polymer liquid rubber and preparation method, the invention has the advantages that the terminal polyhydroxy conjugated olefin polymer liquid rubber or the terminal polyhydroxy conjugated olefin polymer liquid rubber with hydroxyl groups distributed in the molecular chain can be directly obtained by polymerization and end-capping in one pot, the preparation process is simple, the cost is low, and it is suitable for industrial production; the invention introduces polyhydroxy structures on both sides of the polyconjugated olefin main chain, which can greatly increase the reaction speed with isocyanate, reduce the curing time, increase the number of carbamate groups formed, thereby increasing the intermolecular cohesion and improving the mechanical properties of the polyurethane elastomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 For Example 4 1 H NMR spectrum; Figure 2 For Example 4 1 A partial enlarged view of the H NMR spectrum; Figure 3 For comparative example 1 1 H NMR spectrum; Figure 4 For comparative example 2 1 A partial enlargement of the H NMR spectrum. DETAILED DESCRIPTION

[0023] The present invention is further described below by means of specific examples.

[0024] Example 1

[0025] In a nitrogen atmosphere, 0.5 mol of n-butyl lithium and 4 L of n-hexane were added to a dry and sealed 10 L polymerization reactor in sequence, stirred and heated to 50 °C, and a mixture of 1 kg of isoprene and 1 kg of styrene was added in batches. After the feeding was completed and reacted for 1 hour, 1.0 mol of 3-ethyl-3-[(epoxyethyl-2-methoxy)methyl]-oxetane was added at 60 °C, and ethanol was added to terminate the reaction at 60 °C for 2 hours. The resulting reaction mixture was acid-washed with 2.5 mol of hydrochloric acid for 3 hours and then washed with water to neutrality. The organic phase was dried at 120 °C for 3 hours to obtain 2 kg of terminal polyhydroxy isoprene-styrene copolymer, whose number average molecular weight was 4000 and functionality was 2.9. The structure is shown below:

[0026] Example 2

[0027] In a nitrogen atmosphere, 0.5 mol of 1,4-dilithium butane and 4 L of ether were added to a dry and sealed 10 L polymerization reactor in sequence, stirred and cooled to 0 °C, and a mixture of 1 kg of butadiene and 1 kg of styrene was added in batches. After the feeding was completed and reacted for 1 hour, 2.0 mol of 3-ethyl-3-[(epoxyethyl-2-methoxy)methyl]-oxetane was added at 50 °C, and ethanol was added to terminate the reaction at 50 °C for 2 hours. The resulting reaction mixture was acid-washed with 4.0 mol of hydrochloric acid for 2 hours and then washed with water to neutrality. After the organic phase was dried at 120 °C for 3 hours, 2 kg of butadiene-styrene copolymer with polyhydroxy groups at the end was obtained, and its number average molecular weight was 4100, and the functionality was 5.8. The structure is shown below:

[0028] Example 3

[0029] In a nitrogen atmosphere, 0.5 mol 1,4-dilithium butane and 4 L ether were added to a dry and sealed 10 L polymerization reactor in sequence, stirred and cooled to 0 °C, 2 kg butadiene was added in batches, and after the feeding was completed and reacted for 1 h, 0.5 mol of 3-ethyl-3-[(oxiran-2-methoxy)methyl]-oxetane was added at 50 °C and reacted at 50 °C for 3 h, 2.0 mol of 3-ethyl-3-[(oxiran-2-methoxy)methyl]-oxetane was added, and ethanol was added to terminate the reaction at 50 °C for 3 h. The obtained reaction mixture was acid-washed with 4.0 mol hydrochloric acid for 2 h and then washed with water to neutrality. The organic phase was dried at 130 °C for 2 h to obtain 2.1 kg of polyhydroxy polybutadiene with hydroxyl groups distributed in the middle of the molecular chain, with a number average molecular weight of 8200 and a functionality of 7.6. The structure is shown below:

[0030] Example 4

[0031] In a nitrogen atmosphere, 0.5 mol of dilithium butadiene oligomer initiator with a molecular weight of 1000 g / mol and 4 L of cyclohexane were added to a dry and sealed 10 L polymerization reactor in sequence, stirred and heated to 60 °C, 2 kg of butadiene was added in batches, and after the feeding was completed and reacted for 1 h, 0.3 mol of 3-ethyl-3-[(oxiran-2-methoxy)methyl]-oxetane and 2 mol of ethylene oxide were added at 60 °C, and ethanol was added to terminate the reaction after reacting at 60 °C for 2 h. The resulting reaction mixture was acid-washed with 3 mol of hydrochloric acid for 3 h and then washed with water to neutrality. After the organic phase was dried at 120 °C for 3 h, 2 kg of polyhydroxy-terminated polybutadiene was obtained, with a number average molecular weight of 5000 and a functionality of 3.0. The structure is shown below:

[0032] product 1 The H NMR characterization results are shown in Figure 1 and Figure 2 . Figure 1 For the product of Example 4 1 H NMR spectrum, Figure 2 for Figure 1 A partial enlarged view of Figure 2 As shown, the NMR peak at 3.20~3.70 ppm is the methylene peak connected to the hydroxyl group, among which the NMR peak at 3.50~3.70 ppm is the methylene peak connected to the hydroxyl group in structure (III), and the NMR peak at 3.40~3.50 ppm is the methylene peak connected to the hydroxyl group in structure (IV).

[0033] Comparative Example 1

[0034] In a nitrogen atmosphere, 0.5 mol of dilithium butadiene oligomer initiator with a molecular weight of 1000 g / mol and 4 L of cyclohexane were added to a dry and sealed 10 L polymerization reactor in sequence, stirred and heated to 60 °C, 2 kg of butadiene was added in batches, and after the feeding was completed and reacted for 1 h, 2.5 mol of ethylene oxide was added at 60 °C, and ethanol was added to terminate the reaction after reacting at 60 °C for 2 h. The resulting reaction mixture was added with 3 mol of hydrochloric acid for acid washing for 3 h and then washed with water to neutrality. After the organic phase was dried at 120 °C for 3 h, 2 kg of terminal hydroxyl polybutadiene was obtained, with a number average molecular weight of 5000 and a functionality of 1.8. The structure is shown below:

[0035] product 1 The H NMR characterization results are as follows Figure 3 and Figure 4 . Figure 3For the product of Comparative Example 1 1 H NMR spectrum, Figure 4 for Figure 3 A partial enlarged view of the Figure 4 As shown, the NMR peak at 3.20-3.70 ppm is the methylene peak connected to the hydroxyl group. Compared with the spectrum of the product of Example 4, it can be observed that the product of Comparative Example 1 has fewer hydroxyl types and only contains the hydroxyl group in structure (III).

[0036] Application Example 1

[0037] 500 g of hydroxy-terminated polybutadiene (product of Example 4), 60 g of toluene diisocyanate, and 10 g of 1,4-butanediol chain extender were added to a 1 L glass flask, stirred and reacted at 70 °C for 5 h, then poured into a stainless steel mold, placed in a 70 °C oven for reaction for 72 h and completely cured, cooled to room temperature, and then removed from the mold to obtain polyurethane film A.

[0038] Application Example 2

[0039] In a 1 L glass flask, 500 g of terminal hydroxyl polybutadiene (product of comparative example 1), 35 g of toluene diisocyanate, and 10 g of 1,4-butanediol chain extender were added. After stirring and reacting at 70 °C for 5 h, the mixture was poured into a stainless steel mold and placed in a 70 °C oven for reaction for 240 h to completely cure. After cooling to room temperature, the mold was removed to obtain a polyurethane film B.

[0040] Application Example 3

[0041] In a 1 L glass flask, 500 g of hydroxyl-terminated polybutadiene (free radical hydroxyl-terminated polybutadiene, molecular weight 5000, functionality 2.5, produced by Liming Chemical Research and Design Institute), 45 g of toluene diisocyanate, and 10 g of 1,4-butanediol chain extender were added. After stirring and reacting at 70 °C for 5 h, the mixture was poured into a stainless steel mold and placed in a 70 °C oven for curing for 72 h. After cooling to room temperature, the mold was removed to obtain polyurethane film C.

[0042] The mechanical properties of polyurethane film are shown in Table 1 below (test method is GJB 770B-2005): Table 1 Mechanical properties of polyurethane film

[0043] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A polyhydroxy conjugated olefin polymer, wherein the polyhydroxy conjugated olefin polymer has the structural formula (I) or (II): （Ⅰ）、 （Ⅱ）； in, R1 is -C4H9, -C2H5O, -C3H7O or -C9H 19 O4; R2 is -H or -CH3; R3 is -C6H5 or -C8H7; R4 is C4H9, -C2H5O, -C3H7O or -C9H 19 O4; m = 0 ~ 200, n = 0 ~ 200, x = 0 ~ 200, y = 1 ~ 10, and m, n, x are not 0 at the same time; In formula (I) and (II), at least one of R1 and R4 is -C9H 19 O4.

2. A method for preparing a polyhydroxy conjugated olefin polymer, comprising the following steps: (1) Under the protection of inert gas, add anionic initiator and solvent into the reactor, stir evenly and heat to the reaction temperature; (2) adding a conjugated olefin monomer at a reaction temperature to carry out free radical solution polymerization; (3) After the polymerization is completed, a capping agent is added to carry out a capping reaction; (4) After the end-capping is completed, a terminator is added to terminate the reaction, and the reaction solution is treated by acid washing, water washing, and drying to obtain a polyhydroxy conjugated olefin polymer; The end-capping agent is an epoxy end-capping agent A, or the end-capping agent is a mixture of an epoxy end-capping agent A and an epoxy end-capping agent B; The epoxy end-capping agent A is 3-ethyl-3-[(oxiranyl-2-methoxy)methyl]-oxetane, and the structure is shown below: ； The epoxy capping agent B is one of ethylene oxide and propylene oxide or a mixture of the two.

3. The preparation method according to claim 2, characterized in that: The anionic initiator is a monolithium initiator and / or a dilithium initiator.

4. The preparation method according to claim 3, characterized in that: The monolithium initiator is selected from one or more of n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and tert-butyl dimethylsiloxypropyl lithium; the dilithium initiator is selected from one or more of 1,4-dilithium butane initiator, 1,5-dilithium pentane initiator, 1,6-dilithium hexane initiator, dilithium divinylbenzene initiator, dilithium isoprene polymer initiator, dilithium butadiene polymer initiator, and dilithium styrene polymer initiator.

5. The preparation method according to claim 2, characterized in that: The conjugated olefin monomer is one or a mixture of butadiene, isoprene, styrene and divinylbenzene; preferably, it is one or a mixture of two of butadiene, isoprene and styrene.

6. The preparation method according to claim 2, characterized in that The polymerization reaction temperature is -20~80°C, preferably 0~60°C.

7. The preparation method according to claim 2, characterized in that The end-capping reaction temperature is 30-80°C, preferably 50-70°C.

8. The preparation method according to claim 2, characterized in that In step (3), the end-capping agent is an epoxy end-capping agent A, which is added at one time, and the amount of the epoxy end-capping agent A is 200 mol% or more of the amount of the monolithium anion initiator, or 400 mol% or more of the amount of the dilithium anion initiator.

9. The preparation method according to claim 2, characterized in that In step (3), the end-capping agent is an epoxy end-capping agent A and an epoxy end-capping agent B, and the epoxy end-capping agent A and the epoxy end-capping agent B are added simultaneously, and the amount of the epoxy end-capping agent A is 5-50 mol% of the amount of the monolithium anion initiator, or 10-100 mol% of the amount of the dilithium anion initiator; the amount of the epoxy end-capping agent B is 100-200 mol% of the amount of the monolithium anion initiator, or 200-400 mol% of the amount of the dilithium anion initiator.

10. The preparation method according to claim 2, characterized in that In step (3), the epoxy capping agent A is added in batches: ① first add 10-100 mol% of the epoxy capping agent A in an amount equivalent to the dilithium anion initiator, and keep it at the reaction temperature for 1-3 h; ② add 400 mol% of the epoxy capping agent A in an amount equivalent to the dilithium anion initiator, or add 10-100 mol% of the epoxy capping agent A in an amount equivalent to the dilithium anion initiator and 200-400 mol% of the epoxy capping agent B in an amount equivalent to the dilithium anion initiator at the same time.

Images