A transparent copolymer resin and its preparation method and use

Abstract

A method for preparing a transparent copolymer resin, the method comprising the following steps: a) mixing (meth) alkyl acrylate monomer, acrylamide monomer, aromatic vinyl monomer, unsaturated nitrile monomer and reaction medium to prepare a reaction mixture; b) adding an organic peroxide initiator, a chain transfer agent to the reaction mixture to prepare a polymerization mixture; c) mixing the aromatic vinyl monomer and the unsaturated nitrile monomer to obtain a mixed solution; d) adding the polymerization mixture of b) to a reactor to carry out a bulk polymerization reaction, while the mixed solution of c) is added dropwise into the reactor at a speed of preferably 0.5-10 g / min, and a transparent copolymer resin is obtained after the reaction is completed. The transparent resin has lower odor, lower processing temperature and good color phase due to good flowability, and high transparency.

Description

TECHNICAL FIELD

[0001] The present invention relates to a kind of transparent copolymer resin and its preparation method and use. It has good transparency, flowability and low odor. BACKGROUND

[0002] Styrene-acrylonitrile-acrylate terpolymer is a kind of transparent resin, which can be used as plastic alone, but mainly mixed with grafting rubber such as acrylonitrile-butadiene-styrene (ABS) to prepare transparent ABS.

[0003] Chinese patent with publication number CN1372579A discloses a kind of styrene-acrylonitrile-methyl methacrylate terpolymer prepared by bulk polymerization, by controlling the proportion of monomers, the refractive index of the resin is regulated in the range of 1.513-1.521, and transparent ABS resin composition is prepared.

[0004] Chinese patent with publication number CN101072803A discloses a kind of resin composition with good transparency, drug resistance and anti-fading prepared by bulk polymerization of styrene monomer, methyl methacrylate monomer and acrylonitrile monomer and antioxidant.

[0005] The copolymer of styrene monomer, methyl methacrylate monomer and acrylonitrile monomer and the transparent resin composition prepared in the above patent documents are mainly used to improve the transparency, and the existence of antioxidant introduced to relieve the poor heat resistance of acrylonitrile and styrene, so that the color of the resin is optimized, but the introduction of antioxidant makes the transparency of the resin have a certain degree of loss.

[0006] It is known that the polymer containing polyacrylonitrile is easy to cyan ring at high temperature, which makes the product yellow, bulk polymerization can avoid the introduction of a large amount of small molecule additives, and obtain polymer resin with high transparency, but this method needs to increase the temperature after polymerization to remove the un-polymerized monomer, reduce the small molecule residue and reduce the odor of the resin, and at the same time, high temperature is easy to cause the deterioration of the color of the resin.

[0007] Therefore, it is very necessary to develop a kind of styrene-acrylonitrile-acrylate resin with high transparency, good flowability and not easy to yellow. SUMMARY

[0008] In order to solve the above technical problems, the present invention provides a kind of transparent copolymer resin preparation method, more specifically, the present invention relates to a kind of method for preparing styrene-acrylonitrile-acrylate-acrylamide quaternary copolymer transparent resin and the styrene-acrylonitrile-acrylate-acrylamide quaternary copolymer transparent resin prepared by the method, the transparent resin has lower odor, lower processing temperature and good color due to good flowability, and high transparency.

[0009] The present application introduces acrylamide monomer into the main chain structure of the copolymer, so that the main chain has flexible side groups, which effectively inhibit the cyclization of the cyano group of polyacrylonitrile through molecular chain vibration, and improve the color change of the polymer during high temperature treatment. In addition, the flexible side groups increase the molecular chain spacing, so that the polymer chain has better flowability, the polymer devolatilization and processing temperature can be reduced, the low molecular weight substances can be better removed, and the resin odor is reduced.

[0010] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0011] The present application provides a method for preparing a transparent copolymer resin by bulk polymerization of a mixture, which polymerizes by introducing an acrylamide-containing monomer to improve the flexibility of the molecular chain, inhibit the cyclization of the cyano group between polyacrylonitrile molecules, and improve the color of the resin under high temperature processing environment. At the same time, by adding active monomers during the polymerization process, the average composition and its distribution of the copolymer are optimized, and the optical and mechanical properties of the transparent resin are improved.

[0012] A method for preparing a transparent copolymer resin, the method comprising the following steps:

[0013] a) mixing (meth) alkyl acrylate monomer, acrylamide monomer, aromatic vinyl monomer, unsaturated nitrile monomer and reaction medium to prepare a reaction mixture;

[0014] b) adding an organic peroxide initiator and a chain transfer agent to the reaction mixture to prepare a polymerization mixture;

[0015] c) mixing the aromatic vinyl monomer and the unsaturated nitrile monomer to obtain a mixed solution;

[0016] d) adding the polymerization mixture of b) to the reactor to carry out bulk polymerization, and simultaneously dropping the mixed solution of c) into the reactor at a speed of 0.5-10 g / min, and after the reaction is completed, the temperature is preferably raised to 210-240℃, and gradually vacuumed to a vacuum degree of -0.08 MPa to -0.1 MPa, and maintained for 30-40 min to remove un-polymerized monomers, and obtain a transparent copolymer resin.

[0017] Preferably, the amount of each component in step a) is: 30-60 parts by weight of (meth) alkyl acrylate monomer, 20-40 parts by weight of acrylamide monomer, 5-15 parts by weight of aromatic vinyl monomer, 1-5 parts by weight of unsaturated nitrile monomer, and 10-20 parts by weight of reaction medium based on the total amount of monomers.

[0018] Preferably, in step b), based on 100 parts by weight of the reaction mixture of a), 0.01-0.05 parts by weight of an organic peroxide initiator and 0.05-0.2 parts by weight of a chain transfer agent are added to the reaction mixture to prepare a polymerization mixture.

[0019] Preferably, in step c), based on 100 parts by weight of the reaction mixture of a), the mixture of the aromatic vinyl monomer and the unsaturated nitrile monomer is used in an amount of 5-15 parts by weight.

[0020] As a preferred solution, the method comprises the following steps:

[0021] a) mixing 30-60 parts by weight of an alkyl (meth)acrylate monomer, 20-40 parts by weight of an acrylamide monomer, 5-15 parts by weight of an aromatic vinyl monomer, 1-5 parts by weight of an unsaturated nitrile monomer, and 10-20 parts by weight of a reaction medium based on the total amount of monomers to prepare a reaction mixture;

[0022] b) based on 100 parts by weight of the reaction mixture of a), 0.01-0.05 parts by weight of an organic peroxide initiator and 0.05-0.2 parts by weight of a chain transfer agent are added to the reaction mixture to prepare a polymerization mixture;

[0023] c) based on 100 parts by weight of the reaction mixture of a), mixing 5-15 parts by weight of a mixture of the aromatic vinyl monomer and the unsaturated nitrile monomer;

[0024] d) adding the polymerization mixture of b) to a reactor, preferably, carrying out bulk polymerization at 145-150°C, maintaining the polymerization for 2-2.5 hours, while dropping the mixture of c) into the reactor at a speed of 0.5-10 g / min, after the reaction is completed, continuing to heat to 210-240°C, and gradually vacuuming to a vacuum degree of -0.08 MPa to -0.1 MPa, maintaining for 30-40 min, removing the un-polymerized monomers to obtain a transparent copolymer resin.

[0025] Due to the different reactivity ratios of the monomers in the multi-component copolymerization, there is no constant ratio copolymerization point, and the copolymerization composition changes with the increase of the conversion rate. The unsaturated nitrile monomer with high activity and the aromatic vinyl monomer will react preferentially, and the monomer concentration in the system will decrease with the increase of the conversion rate, resulting in a wide distribution of the copolymer composition and ultimately poor performance of the resin. Controlling the average composition and uniform distribution of the copolymer can improve the overall performance of the resin.

[0026] As a preferred solution, in the mixture of the aromatic vinyl monomer and the unsaturated nitrile monomer of step c), the mass ratio of the aromatic vinyl monomer to the unsaturated nitrile monomer is 1:1-3:1.

[0027] Preferably, the (meth)acrylic alkyl ester monomer used to prepare the transparent copolymer resin of the present application is at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, more preferably, the (meth)acrylic alkyl ester is methyl methacrylate.

[0028] Preferably, the aromatic vinyl monomer used to prepare the transparent copolymer resin of the present application is at least one selected from the group consisting of styrene, α-methyl styrene, more preferably, the aromatic vinyl monomer is styrene.

[0029] Preferably, the unsaturated nitrile monomer used to prepare the transparent copolymer resin of the present application is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, more preferably, the unsaturated nitrile monomer is acrylonitrile.

[0030] Preferably, the acrylamide monomer used to prepare the transparent copolymer resin of the present application is at least one selected from the group consisting of acrylamide, methacrylamide, N-hydroxyethyl acrylamide, N-isopropyl acrylamide, more preferably, the acrylamide monomer is N-isopropyl acrylamide.

[0031] Preferably, the reaction medium used in the present application is one or more of cyclohexane, toluene, xylene, ethylbenzene, preferably toluene.

[0032] Preferably, the organic peroxide initiator used in the present application is one or more of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, cumyl peroxide, dicumyl peroxide, more preferably dicumyl peroxide.

[0033] Preferably, the chain transfer agent used in the present application is at least one thiol-based compound selected from the group consisting of tert-dodecyl mercaptan and n-octyl mercaptan, more preferably, the chain transfer agent is n-octyl mercaptan.

[0034] The transparent copolymer resin prepared by the method of the present application has a refractive index of 1.518±0.003 and a glass transition temperature of 80-95°C. It has a monomer residue of 1000 ppm or less, a melt index of 30 or more, a b color value of 1 or less, and the prepared transparent copolymer resin can be used as a base resin for transparent ABS. DETAILED DESCRIPTION

[0035] The present application will be further described by specific examples, which are only illustrative of the present application and do not limit the scope of the present application.

[0036] The copolymer-related structure and property test methods are as follows:

[0037] Glass transition temperature (Tg): tested by METTLER instrument, Switzerland, unit: °C;

[0038] Copolymer composition: tested by JEOL nuclear magnetic resonance spectrometer, Japan, unit: %;

[0039] Monomer residue (GC): tested by Agilent 7890B instrument, unit: ppm;

[0040] Color (b value): measured by Hunter Lab colorimeter to measure the yellowness index of the sample;

[0041] Melt index (MVR): tested by CEAST MF30 melt indexer, unit: cm 3 / 10 min;

[0042] Refractive index (RI): measured according to ASTM standard D 542.

[0043] Haze (H): measured according to ASTM standard D 1003.

[0044] The main raw material information is shown in Table 1:

[0045] Table 1, main raw material information

[0046] Raw materials CAS Purity Manufacturer Methyl methacrylate (MMA) 80-62-6 99.5％ Aladdin Styrene (SM) 100-42-5 99.9％ Sigma-Aldrich Acrylonitrile (AN) 107-13-1 99.9％ Sigma-Aldrich Acrylamide (AM) 79-06-1 99.0％ Sigma-Aldrich N-Isopropyl acrylamide (NIPAM) 2210-25-5 99.5％ Sigma-Aldrich N-Hydroxyethyl acrylamide (NHEMAA) 7646-67-5 99.0％ Sigma-Aldrich n-Octyl mercaptan (NOM) 111-88-6 99.5％ Korea Pilmac Tert-dodecyl mercaptan (TDM) 25103-58-6 99.0％ Korea Pilmac Dicumyl peroxide (DCP) 80-43-3 98.5％ Aladdin Toluene (TN) 108-88-3 99.5％ Sigma-Aldrich Ethyl benzene (EB) 100-41-4 98.5％ Aladdin

[0047] Example 1

[0048] The styrene-acrylonitrile-acrylate-acrylamide quaternary copolymer was prepared according to the following method:

[0049] 900 g of toluene, 1800 g of methyl methacrylate, 1700 g of N-isopropyl acrylamide, 450 g of styrene, 150 g of acrylonitrile, 7.5 g of n-octyl mercaptan and 1.5 g of dicumyl peroxide were mixed in a reactor using a free radical bulk polymerization method. After the reactor was heated to 145°C, the reaction was carried out for 2 hours, and at the same time, a mixture of 500 g of styrene and 250 g of acrylonitrile was added into the reactor at a rate of 6 g / min. After the reaction was completed, the reactor was further heated to 220°C, and vacuum was gradually drawn to a vacuum degree of -0.1 MPa, and maintained for 30 min. After removing the un-polymerized monomers, a transparent copolymer resin was obtained. The product analysis and copolymer performance test results are shown in Table 2.

[0050] Examples 2-6

[0051] Transparent copolymer resins were prepared according to the corresponding reaction conditions in Table 2, respectively. The product analysis and copolymer performance test results are shown in Table 2, respectively.

[0052] Comparative Example 1

[0053] The transparent copolymer resin was prepared according to the same process as in Example 1, except that the acrylamide monomer was not added and the (styrene / acrylonitrile) mixture was directly added to the polymerization mixture. The product analysis and copolymer performance test results are shown in Table 2, respectively.

[0054]

Comparative Example 2

[0055] The copolymer was prepared according to the same process as in Example 1, except that the acrylamide monomer was not added. The product analysis and copolymer performance test results are shown in Table 2, respectively.

[0056]

Comparative Example 3

[0057] The copolymer was prepared according to the same process as in Example 1, except that the (styrene / acrylonitrile) mixture was directly added to the polymerization mixture. The product analysis and copolymer performance test results are shown in Table 2, respectively.

[0058] According to the test results in Table 2, the α-methylstyrene copolymer prepared according to the present application has high fluidity, thermal stability and heat resistance, and the resin has low monomer residual amount and high whiteness.

[0059] The above description is only preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and supplements without departing from the method of the present application, and these improvements and supplements should also be considered as the protection scope of the present application.

[0060] Table 2, reaction conditions and product test results of Examples 1-6 and Comparative Examples 1-3

[0061]

[0062]

Claims

1. A method for preparing a transparent copolymer resin, characterized in that, The method includes the following steps: a) Mix (meth)acrylate alkyl ester monomers, acrylamide monomers, aromatic vinyl monomers, unsaturated nitrile monomers, and reaction media to prepare a reaction mixture; b) Add an organic peroxide initiator and a chain transfer agent to the reaction mixture to prepare a polymerization mixture; c) Mixing aromatic vinyl monomers and unsaturated nitrile monomers to obtain a mixture; d) Add the polymerization mixture described in b) to the reactor to carry out a bulk polymerization reaction, while simultaneously adding the mixture described in c) dropwise into the reactor. After the reaction is completed, a transparent copolymer resin is obtained. The amounts of each component in step a) are: 30-60 parts by weight of (meth)acrylate alkyl ester monomer, 20-40 parts by weight of acrylamide monomer, 5-15 parts by weight of aromatic vinyl monomer, 1-5 parts by weight of unsaturated nitrile monomer, and 10-20 parts by weight of reaction medium based on the total amount of monomers.

2. The method according to claim 1, characterized in that, In step b), based on 100 parts by weight of the reaction mixture described in a), 0.01-0.05 parts by weight of an organic peroxide initiator and 0.05-0.2 parts by weight of a chain transfer agent are added to the reaction mixture to prepare a polymerization mixture.

3. The method according to claim 1, characterized in that, In step c), based on 100 parts by weight of the reaction mixture described in a), the amount of the mixture of aromatic vinyl monomer and unsaturated nitrile monomer is 5-15 parts by weight.

4. The method according to claim 1, characterized in that, The bulk polymerization reaction is carried out at a temperature of 145–150°C for 2–2.5 hours.

5. The method according to claim 1, characterized in that, In step d), the mixture is added dropwise to the reactor at a rate of 0.5-10 g / min.

6. The method according to claim 1, characterized in that, In step d), after the reaction is complete, the temperature is raised to 210-240°C and the vacuum is gradually reduced to -0.08MPa to -0.1MPa. The vacuum is maintained for 30-40 minutes to remove unpolymerized monomers and obtain a transparent copolymer resin.

7. The method according to claim 1, characterized in that, In step c), the mass ratio of aromatic vinyl monomer to unsaturated nitrile monomer is 1:1 to 3:

1.

8. The method according to any one of claims 1-7, characterized in that, The alkyl methacrylate monomer is selected from one or more of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate; and / or the acrylamide monomer is selected from one or more of acrylamide, methacrylamide, N-hydroxyethyl acrylamide, and N-isopropylacrylamide.

9. The method according to any one of claims 1-7, characterized in that, The aromatic vinyl monomer is selected from one or two of styrene and α-methylstyrene, and / or the unsaturated nitrile monomer is selected from one or more of acrylonitrile and methacrylonitrile; and / or the reaction medium is one or more of benzene, toluene, xylene, and ethylbenzene.

10. The method according to any one of claims 1-7, characterized in that, The organic peroxide initiator is one or more of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, and dicumyl peroxide; and / or, the chain transfer agent is one or two selected from tert-dodecylthiol and n-octylthiol.

11. A transparent copolymer resin prepared by the method according to any one of claims 1-10, characterized in that, Its refractive index is 1.518±0.003, and its glass transition temperature is 80~95℃.

12. The transparent copolymer resin according to claim 11, characterized in that, It has a monomer residue of 1000 ppm or less, a melt index of 30 or higher, and a b color value of 1 or lower.

13. Use of the transparent copolymer resin prepared by the method according to any one of claims 1-10 or the transparent copolymer resin according to any one of claims 11-12 as a matrix resin for transparent ABS.

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