A blend of polyvinyl chloride and a plasticizing and toughening agent and a preparation method thereof

Abstract

The present invention discloses a blend of polyvinyl chloride and a plasticizing and toughening agent and a preparation method thereof. Under the same mixing conditions, the blend of the polycarbonate block copolymer and polyvinyl chloride of the present invention has more ester bonds and long branched chains in the elastomer, and has more excellent plasticizing and toughening effects compared with the existing commercial toughening agents. It can significantly improve the processing performance of polyvinyl chloride, reduce the glass transition temperature, improve the toughness, and significantly increase the elongation at break of polyvinyl chloride. Compared with the commercially available polyvinyl chloride toughening and modifying agents, the polycarbonate block copolymer has the advantages of being degradable, having excellent toughening effects, and having a relatively low preparation cost. At the same time, due to its high molecular weight, it has the advantages of being non-toxic, not easy to migrate or leach, etc., and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically, to a blend of polyvinyl chloride and a plasticizing and toughening agent and a preparation method thereof. Background Art

[0002] As a general-purpose plastic, polyvinyl chloride (PVC) has a large and steadily growing market demand. Its consumption is second only to polyethylene, and it is widely used in many fields such as medical devices, packaging, construction, and toys. Due to the interaction of polar bonds C-Cl between PVC chains, the mobility of the chain segments is hindered, making it exhibit brittle and hard characteristics and difficult to process thermally, which limits its application.

[0003] PVC plastics usually cannot be used directly because of their poor thermal stability and impact strength. Appropriate plasticizers and toughening agents need to be added to improve the processability, flexibility, impact resistance, etc. of PVC. Currently, the commercial plasticizer phthalate esters (DOP) have been banned due to their carcinogenicity. Dioctyl terephthalate (DOTP) is non-toxic and is widely used as a substitute for DOP. However, due to its low molecular weight, there is also a problem of easy migration. High molecular weight plasticizing and toughening agents such as polyacrylate esters (ACR) and methyl methacrylate-butadiene-styrene copolymer (MBS) can plasticize and toughen PVC better and are not easy to migrate, but they have problems such as high cost and complex preparation processes. Summary of the Invention

[0004] The object of the present invention is to overcome the above-mentioned defects and deficiencies existing in the prior art, and to provide a blend of polyvinyl chloride and a plasticizing and toughening agent obtained by modifying polyvinyl chloride with a core-shell polycarbonate block copolymer.

[0005] The above object of the present invention is achieved by the following technical solutions:

[0006] A blend of polyvinyl chloride and a plasticizing and toughening agent, wherein the plasticizing and toughening agent is a polycarbonate block copolymer, and the mass ratio of polyvinyl chloride to the polycarbonate block copolymer is 100:5 - 100:60.

[0007] The structural formula of the polycarbonate block copolymer is shown in formula (Ⅰ) or formula (Ⅱ), wherein a≥1, b≥1, c≥0, d≥1, e≥1, f≥0, n≥1; a, b, c, d, e, f, n are all integers, and R is H or Cl;

[0008]

[0009] Preferably, the molecular weight of the copolymer ranges from 1000 to 200,000 Da, the molar content of the polycarbonate in formula (I) is 70% - 100%; the weight content of the polycarbonate in formula (II) is 40% - 90%, and the weight content of the polyester is 60% - 10%.

[0010] The preparation method of the polycarbonate block copolymer comprises the following steps:

[0011] S1: Add a double initiator, a catalyst and allyl glycidyl ether into a high-pressure reactor under anhydrous and anaerobic conditions, fill with carbon dioxide, and stop the reaction after reacting for a period of time under magnetic stirring and heating conditions;

[0012] S2-I: After the reaction in S1 ends, under anhydrous and anaerobic conditions, continue to add cyclohexene oxide, fill with carbon dioxide, react under magnetic stirring and heating conditions, dissolve the product with dichloromethane after the reaction ends, and precipitate and purify in ethanol to obtain an intermediate of the product of formula (I);

[0013] S2-II: After the reaction in S1 ends, under anhydrous and anaerobic conditions, continue to add propylene oxide, phthalic anhydride or tetrachlorophthalic anhydride, react under magnetic stirring and heating conditions, dissolve the product with dichloromethane after the reaction ends, and precipitate and purify in ethanol to obtain an intermediate of the product of formula (II);

[0014] S3: Dissolve the purified intermediate in S2 in dichloromethane, add an alkyl mercaptan and a photoinitiator, and react the alkyl mercaptan with the double bond under ultraviolet radiation to form long branched chains, obtaining the final polymerization products of formula (I) and formula (II).

[0015] Preferably, the double initiator in step S1 is a quaternary ammonium phthalate, and the structure is as shown in formula (III); the catalyst in step S1 is triethylboron, triphenylboron or tris(pentafluorophenyl)boron. The molar ratio of the double initiator, catalyst and allyl glycidyl ether in step S1 is 1:5 - 20:500 - 5000; the reaction pressure of carbon dioxide in step S1 is 1 - 3 MPa, the reaction temperature is 40 - 60 °C, and the reaction time is 10 - 30 h; the reaction in step S1 is bulk polymerization or solution polymerization, and the solution used for solution polymerization is toluene, n-hexane or tetrahydrofuran;

[0016]

[0017] Preferably, in step S2-I, the molar ratio of cyclohexene oxide to allyl glycidyl ether in S1 is 1 - 3:1, the reaction pressure of carbon dioxide is 1 - 3 MPa, the temperature is 40 - 60 °C, and the reaction time is 2 - 10 h;

[0018] In step S2-II, the molar ratio of propylene oxide to phthalic anhydride or tetrachlorophthalic anhydride is 1:0.5-2, the molar ratio of the initiator in S1 to propylene oxide is 1:500-2000, the reaction temperature is 40-60°C, and the reaction time is 1-10 h.

[0019] Preferably, in step S3, the addition amount of the alkyl mercaptan is 1-1.4 times the number of C=C double bonds contained in the polymer, and the added weight of the photoinitiator is 0.1-0.5% of the weight of the polymer; the wavelength of the ultraviolet light is 360-365 nm, the light intensity is 35 mW / cm 2 , the exposure time is 1-20 min, and the reaction temperature is room temperature.

[0020] Preferably, the photoinitiator is 2,2-dimethoxy-2-phenylethanone.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. Under the same mixing conditions, the blend of the polycarbonate block copolymer provided by the present invention and polyvinyl chloride has more ester bonds and long branched chains in the elastomer. Compared with the existing commercial toughening agents, it has more excellent plasticizing and toughening effects, can significantly improve the processing performance of polyvinyl chloride, reduce the glass transition temperature, improve toughness, and significantly increase the elongation at break of polyvinyl chloride.

[0023] 2. The polycarbonate block copolymer prepared by the present invention is non-toxic, has a relatively high molecular weight, is not easy to migrate or leach from the product body, and can maintain good tensile strength and high transparency while plasticizing and toughening polyvinyl chloride.

[0024] 3. The raw materials of the present invention use cheap bulk chemical raw materials, and the raw materials contain carbon dioxide, which has the advantages of rapid reaction, low cost, degradability, and environmental friendliness, and is conducive to large-scale commercial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the nuclear magnetic resonance hydrogen spectrum (deuterochloroform as the solvent) of the polycarbonate block copolymer obtained in Example 1 of the present invention.

[0026] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum (deuterochloroform as the solvent) of the polycarbonate block copolymer obtained in Example 4 of the present invention.

[0027] Figure 3 It is the nuclear magnetic resonance hydrogen spectrum (deuterochloroform as the solvent) of the polycarbonate block copolymer obtained in Example 5 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments. However, the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0029] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0030] Example 1. Preparation of Polycarbonate Block Copolymer (CAC-1)

[0031] Under anhydrous and anaerobic conditions, 1 mmol of quaternary ammonium phthalate, 10 mmol of triphenylboron, 2000 mmol of allyl glycidyl ether, and 1500 mmol of tetrahydrofuran were successively added to a high-pressure reactor. The mixture was heated in an oil bath at 50 °C, magnetically stirred, and carbon dioxide was introduced at a pressure of 2 MPa for 24 h. After the reaction stopped, under anhydrous and anaerobic conditions, 6000 mmol of cyclohexene oxide was further added, and the mixture was heated in an oil bath at 50 °C. Carbon dioxide was introduced at a pressure of 2 MPa for 6 h. After the reaction ended, the product was dissolved in dichloromethane and precipitated in ethanol to obtain the product, which was vacuum dried at 40 °C for 24 h.

[0032] After each step of the reaction ended, the stock solution was taken for nuclear magnetic resonance hydrogen spectrum ( 1 1H NMR) testing. The conversion rate of allyl glycidyl ether was calculated to be 55%, and the conversion rate of cyclohexene oxide was 22%.

[0033] The dried intermediate was dissolved in dichloromethane. The number of double bonds was calculated based on the conversion rate of allyl glycidyl ether. 1.2 times of n-butyl mercaptan and 0.2 wt% photoinitiator 2,2-dimethoxy-2-phenylethanone were added, and a core-shell polycarbonate block copolymer CAC-1 with the structure of formula (IV) was obtained under ultraviolet radiation for 20 min. According to the nuclear magnetic resonance hydrogen spectrum, the hard segment content was calculated to be 34 wt%. The results of gel permeation chromatography (GPC) showed that the number-average molecular weight Mn was 64.6 KDa, and the polydispersity index PDI of the polymer was 2.07. The nuclear magnetic resonance hydrogen spectrum (using deuterated chloroform as the solvent) of the obtained polycarbonate block copolymer is as Figure 1 shown. .

[0034] Example 2. Preparation of Polycarbonate Block Copolymer (CAC-2)

[0035] Under anhydrous and anaerobic conditions, 1 mmol of quaternary ammonium phthalate, 12 mmol of triethylborane, 2500 mmol of allyl glycidyl ether, and 1500 mmol of tetrahydrofuran were successively added to a high-pressure reactor. It was heated in an oil bath at 45 °C with magnetic stirring, carbon dioxide was introduced, the pressure was 1 MPa, and the reaction was carried out for 22 h. After the reaction stopped, under anhydrous and anaerobic conditions, 4000 mmol of cyclohexene oxide was continuously added, heated in an oil bath at 55 °C, carbon dioxide was introduced, the pressure was 2 MPa, and the reaction was carried out for 10 h. After the reaction ended, the product was dissolved in dichloromethane and precipitated in ethanol to obtain the product, which was dried in vacuo at 40 °C for 24 h.

[0036] After each step of the reaction ended, the stock solution was taken for nuclear magnetic resonance hydrogen spectrum ( 1 1H NMR) test, and the conversion rate of allyl glycidyl ether was calculated to be 60%, and the conversion rate of cyclohexene oxide was 25%.

[0037] The dried intermediate was dissolved in dichloromethane. The number of double bonds was calculated according to the conversion rate of allyl glycidyl ether. 1.3 times of n-butyl mercaptan and 0.4 wt% photoinitiator 2,2-dimethoxy-2-phenylethanone were added, and the polymeric product CAC-2 with the structure of formula (IV) was obtained under ultraviolet radiation for 10 min. According to the nuclear magnetic resonance hydrogen spectrum, the hard segment content was calculated to be 48 wt%. The results of gel permeation chromatography (GPC) showed that the number-average molecular weight Mn was 75.7 KDa, and the polydispersity index PDI of the polymer was 1.38.

[0038] Example 3. Preparation of polycarbonate block copolymer (CAC-3)

[0039] Under anhydrous and anaerobic conditions, 1 mmol of quaternary ammonium phthalate, 8 mmol of tris(pentafluorophenyl)borane, 2000 mmol of allyl glycidyl ether, and 1200 mmol of tetrahydrofuran were successively added to a high-pressure reactor. It was heated in an oil bath at 50 °C with magnetic stirring, carbon dioxide was introduced, the pressure was 1.5 MPa, and the reaction was carried out for 24 h. After the reaction stopped, under anhydrous and anaerobic conditions, 5000 mmol of cyclohexene oxide was continuously added, heated in an oil bath at 50 °C, carbon dioxide was introduced, the pressure was 2 MPa, and the reaction was carried out for 10 h. After the reaction ended, the product was dissolved in dichloromethane and precipitated in ethanol to obtain the product, which was dried in vacuo at 40 °C for 24 h.

[0040] After each step of the reaction ended, the stock solution was taken for nuclear magnetic resonance hydrogen spectrum ( 1 1H NMR) test, and the conversion rate of allyl glycidyl ether was calculated to be 50%, and the conversion rate of cyclohexene oxide was 25%.

[0041] Dissolve the dried intermediate in dichloromethane, calculate the number of double bonds based on the conversion rate of allyl glycidyl ether, add 1.2 times of dodecyl mercaptan and 0.3 wt% photoinitiator 2,2-dimethoxy-2-phenylethanone, and obtain the polymeric product CAC-3 with the structure of formula (V) under ultraviolet radiation for 20 min. According to the proton nuclear magnetic resonance spectrum, the hard segment content is calculated to be 34 wt%. The test results of gel permeation chromatography (GPC) show that the number average molecular weight Mn is 98.5 KDa, and the polydispersity index PDI is 1.51.

[0042] 。

[0043] Example 4. Preparation of polycarbonate block copolymer (PAP)

[0044] Under anhydrous and anaerobic conditions, add 1 mmol of quaternary ammonium phthalate, 10 mmol of triphenylboron, 2000 mmol of allyl glycidyl ether and 1500 mmol of tetrahydrofuran into a high-pressure reactor in sequence, heat with an oil bath at 50 °C, stir magnetically, introduce carbon dioxide, with a pressure of 2 MPa, and react for 24 h. After the reaction stops, under anhydrous and anaerobic conditions, continue to add 800 mmol of propylene oxide and 1600 mmol of phthalic anhydride, heat with an oil bath at 50 °C, and react for 4 h. After the reaction is completed, dissolve the product in dichloromethane, precipitate the product in ethanol, and dry it under vacuum at 40 °C for 24 h.

[0045] Take the stock solution after each step of the reaction and perform proton nuclear magnetic resonance spectrum ( 1 1H NMR) test. The conversion rate of allyl glycidyl ether is calculated to be 55%, the conversion rate of propylene oxide is 93%, and the conversion rate of phthalic anhydride is 45%.

[0046] Dissolve the dried intermediate in dichloromethane, calculate the number of double bonds based on the conversion rate of allyl glycidyl ether, add 1.2 times of n-butyl mercaptan and 0.4 wt% photoinitiator 2,2-dimethoxy-2-phenylethanone, and obtain the polymeric product PAP with the structure of formula (VI) under ultraviolet radiation for 20 min. According to the proton nuclear magnetic resonance spectrum, the hard segment content is calculated to be 38 wt%. The test results of gel permeation chromatography (GPC) show that the number average molecular weight Mn is 68.1 KDa, and the polydispersity index PDI is 2.11. The proton nuclear magnetic resonance spectrum (using deuterated chloroform as the solvent) of the obtained polycarbonate block copolymer is as Figure 2 shown.

[0047]

[0048] Example 5. Preparation of polycarbonate block copolymer (TAT)

[0049] Under anhydrous and anaerobic conditions, 1 mmol of quaternary ammonium phthalate, 10 mmol of triethylborane, 2000 mmol of allyl glycidyl ether, and 2000 mmol of tetrahydrofuran were successively added to a high-pressure reactor. The mixture was heated in an oil bath at 45 °C with magnetic stirring, and carbon dioxide was introduced at a pressure of 2 MPa for 36 h. After the reaction stopped, under anhydrous and anaerobic conditions, 500 mmol of propylene oxide and 500 mmol of tetrachlorophthalic anhydride were further added, and the mixture was heated in an oil bath at 50 °C for 6 h. After the reaction ended, the product was dissolved in dichloromethane and precipitated in ethanol to obtain the product, which was dried in vacuo at 40 °C for 24 h.

[0050] After each step of the reaction was completed, the stock solution was taken for nuclear magnetic resonance hydrogen spectrum ( 1 1H NMR) testing. The conversion rate of allyl glycidyl ether was calculated to be 56%, the conversion rate of propylene oxide was 97%, and the conversion rate of phthalic anhydride was 95%.

[0051] The dried intermediate was dissolved in dichloromethane. The number of double bonds was calculated based on the conversion rate of allyl glycidyl ether. 1.2 times the amount of n-butyl mercaptan and 0.4 wt% of photoinitiator 2,2-dimethoxy-2-phenylethanone were added, and the polymeric product TAT with the structure of formula (VII) was obtained under ultraviolet radiation for 20 min. The hard segment content was calculated to be 35 wt% based on nuclear magnetic resonance hydrogen spectrum. The results of gel permeation chromatography (GPC) showed that the number-average molecular weight Mn was 65.6 KDa, and the polydispersity index PDI was 2.08. The nuclear magnetic resonance hydrogen spectrum (using deuterated chloroform as the solvent) of the obtained polycarbonate block copolymer is as Figure 3 shown.

[0052]

[0053] Example 6. Using the synthesized polycarbonate block copolymer to plasticize and toughen PVC

[0054] The polycarbonate block copolymers synthesized in Example 1, Example 2, Example 3, Example 4, and Example 5 were melt-blended with polyvinyl chloride in a Haake mixer at a blending temperature of 180 °C. The addition amount of the calcium-zinc composite heat stabilizer was 3 phr, and the melt-blending time was 5 min. The test results of the mechanical properties and glass transition temperature of the blends are listed in Table 1.

[0055] Commercial plasticizing and toughening agents MBS and ACR were melt-blended with polyvinyl chloride. The experimental method and test method were the same as those in Example 6. The test results of the mechanical properties and glass transition temperature of the blends are listed in Table 1.

[0056]

[0057] As can be seen from Table 1, when the polyester copolymer synthesized by the present invention is used as a plasticizer for polyvinyl chloride and plasticized at a certain ratio, the blend exhibits good plasticity, with higher elongation at break and tensile strength compared to commercial MBS and ACR. The glass transition temperature is significantly lower than 84.6 °C of the experimentally measured pure PVC and 86.3 °C of the comparative example PVC / ACR, showing good plasticizing and toughening effects and being able to greatly reduce the processing temperature.

Claims

1. A blend of polyvinyl chloride and a plasticizing and toughening agent, which consists of polyvinyl chloride and a plasticizing and toughening agent, characterized in that The plasticizer and toughening agent is a polycarbonate block copolymer, and the mass ratio of polyvinyl chloride to the polycarbonate block copolymer is 100:5 - 100:20; the structural formula of the polycarbonate block copolymer is as shown in Formula (Ⅰ) or Formula (Ⅱ), where a≥1, b≥1, c>0, d≥1, e≥1, f>0, n≥3; a, b, c, d, e, f, n are all integers, and R is H or Cl; The preparation method of the polycarbonate block copolymer includes the following steps: S1: Add a double initiator, a catalyst and allyl glycidyl ether into a high-pressure reactor under anhydrous and anaerobic conditions, fill with carbon dioxide, and stop the reaction after reacting for a period of time under magnetic stirring and heating conditions; S2-I: After the reaction in S1 ends, under anhydrous and anaerobic conditions, continue to add cyclohexene oxide, fill with carbon dioxide, react under magnetic stirring and heating conditions, dissolve the product with dichloromethane after the reaction ends, and precipitate and purify in ethanol to obtain an intermediate of the product of Formula (Ⅰ); S2-II: After the reaction in S1 ends, under anhydrous and anaerobic conditions, continue to add propylene oxide, phthalic anhydride or tetrachlorophthalic anhydride, react under magnetic stirring and heating conditions, dissolve the product with dichloromethane after the reaction ends, and precipitate and purify in ethanol to obtain an intermediate of the product of Formula (Ⅱ); S3: Dissolve the purified intermediate in S2-I or S2-II in dichloromethane, add an alkyl mercaptan and a photoinitiator, and react the alkyl mercaptan with the double bond under ultraviolet radiation to form a long branched chain to obtain a final polymeric product with the structure of Formula (Ⅰ) or Formula (Ⅱ); The double initiator described in step S1 is a quaternary ammonium phthalate, and the structure is as shown in Formula (Ⅲ); the catalyst described in step S1 is triethylboron, triphenylboron or tris(pentafluorophenyl)boron, and the molar ratio of the double initiator, catalyst and allyl glycidyl ether described in step S1 is 1:5 - 20:500 - 5000; the reaction pressure of carbon dioxide in step S1 is 1 - 3 MPa, the reaction temperature is 40 - 60 °C, and the reaction time is 10 - 30 h; the reaction in step S1 is bulk polymerization or solution polymerization, and the solution used for solution polymerization is toluene, n-hexane or tetrahydrofuran; 。 2. The blend of polyvinyl chloride and a plasticizing and toughening agent according to claim 1, characterized in that The molecular weight of the copolymer is in the range of 1000 - 200000 Da, and the molar content of polycarbonate in Formula (Ⅰ) is 70% - 100%; the weight content of polycarbonate in Formula (Ⅱ) is 40% - 90%, and the weight content of polyester is 60% - 10%.

3. The blend of polyvinyl chloride and a plasticizing and toughening agent as claimed in claim 1, characterized in that In step S2-I, the molar ratio of cyclohexene oxide to allyl glycidyl ether in S1 is 1 - 3:1, the reaction pressure of carbon dioxide is 1 - 3 MPa, the temperature is 40 - 60 °C, and the reaction time is 2 - 10 h; in step S2-II, the molar ratio of propylene oxide to phthalic anhydride or tetrachlorophthalic anhydride is 1:0.5 - 2, the reaction temperature is 40 - 60 °C, and the reaction time is 1 - 10 h.

4. The blend of polyvinyl chloride and a plasticizing and toughening agent according to claim 1, characterized in that The addition amount of the alkyl mercaptan described in step S3 is 1 - 1.4 times the number of C=C double bonds contained in the polymer, and the added weight of the photoinitiator is 0.1 - 0.5% of the weight of the polymer; the wavelength of the ultraviolet light is 360 - 365 nm, and the light intensity is 35 mW / cm 2 , the exposure time is 1 - 20 min, and the reaction temperature is room temperature.

5. The blend of polyvinyl chloride and a plasticizing and toughening agent according to claim 1, characterized in that The photoinitiator is 2,2-dimethoxy-2-phenylethanone.

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