A polymer for improving the heat distortion temperature of ABS and its preparation method

Abstract

The present invention discloses a polymer for improving the heat distortion temperature of ABS. The preparation raw materials include, by weight: 25 - 50 parts of styrene maleic anhydride copolymer, 50 - 75 parts of aniline compound, and 0.1 - 2 parts of catalyst. In the present invention, through the imidization reaction of the styrene maleic anhydride copolymer with a weight ratio of styrene to maleic anhydride of (1 - 4):1 and aniline first, and then polymerization, the conversion rate of maleimide is increased, the residue of maleic anhydride on the main chain is reduced, and by using 4-dimethylaminopyridine as the catalyst, the styrene-N-phenylmaleimide polymer can be prepared at a lower reaction temperature and in a shorter reaction time, improving the production efficiency and reducing the energy consumption. At the same time, by blending with ABS at a weight ratio of 1:4, the heat distortion temperature and Vicat softening point of ABS are improved, and the compatibility is good and the mechanical properties are excellent after blending with ABS.

Description

Technical Field

[0001] The present invention relates to a polymer for improving the heat distortion temperature of ABS, relates to C08L, and specifically relates to the field of compositions of high molecular compounds. Background Art

[0002] ABS is a commonly used material in the field of polymer materials, but its heat resistance is not good. Currently, on the market, styrene-N-phenylmaleimide polymer is usually introduced as a high-temperature resistant component to improve the heat resistance of ABS. However, the preparation of styrene-N-phenylmaleimide polymer is generally by bulk method, suspension method or solution method. The polymer obtained has a low yield, a long preparation process, a high cost, and the poor color of the polymer will interfere with the body color of ABS. The styrene-N-phenylmaleimide polymer prepared by Denka of Japan needs to react in an environment of 140 °C for 7 hours, with a long reaction time and the introduction of a solvent, and the problem of solvent residue is serious. The styrene-N-phenylmaleimide polymer prepared by Toray has a conversion rate of only 70% for the conversion of maleic anhydride to N-phenylmaleimide, with a low conversion rate, and more maleic anhydride remains in the main chain, resulting in poor thermal stability.

[0003] Chinese invention patent CN202010270394.8 discloses a high heat-resistant composition for toys and its preparation method, introducing styrene-N-phenylmaleimide-maleic anhydride terpolymer as a temperature-resistant component, but the preparation process of the terpolymer is complex and the cost is high. Chinese invention patent CN201410843042.1 discloses a low-high heat-resistant ABS resin and its preparation method, using benzoyl peroxide as an initiator to prepare styrene-N-phenylmaleimide polymer under a nitrogen atmosphere. The yield of the polymer is low, and after adding an excessive amount, the compatibility with ABS will decrease. Summary of the Invention

[0004] In order to prepare styrene-N-phenylmaleimide polymer at a lower reaction temperature and a shorter reaction time and improve the yield of the polymer, the first aspect of the present invention provides a polymer for improving the heat distortion temperature of ABS. The preparation raw materials include, by weight: 25-50 parts of styrene maleic anhydride copolymer, 50-75 parts of aniline compound, and 0.1-2 parts of catalyst.

[0005] As a preferred embodiment, the weight average molecular weight of the styrene maleic anhydride copolymer is 5000-300000.

[0006] As a preferred embodiment, the weight average molecular weight of the styrene maleic anhydride copolymer is 20000.

[0007] As a preferred embodiment, the molar ratio of styrene to maleic anhydride in the styrene maleic anhydride copolymer is (1 - 4):1.

[0008] As a preferred embodiment, the molar ratio of styrene to maleic anhydride in the styrene maleic anhydride copolymer is 2:1.

[0009] As a preferred embodiment, the amino substituents in the aniline compound are selected from one or a combination of several of amino, imino, and tertiary amino.

[0010] As a preferred embodiment, the aniline compound is selected from one or a combination of several of aminobenzene, p-toluidine, o-toluidine, m-toluidine, dimethylaniline, and N-methylaniline.

[0011] As a preferred embodiment, the aniline compound is p-toluidine.

[0012] As a preferred embodiment, the catalyst is selected from one or a combination of several of 4-dimethylaminopyridine, 4-pyrrolidinopyridine, and zinc chloride.

[0013] As a preferred embodiment, the catalyst is 4-dimethylaminopyridine.

[0014] In order to improve the heat resistance of ABS, at present, styrene-N-phenylmaleimide copolymer is introduced. Its unique structure enables ABS to have good heat resistance. However, its monomer N-phenylmaleimide is not easy to prepare, the product purity is low, and the cost is high. During the experiment, the applicant found that under the action of the catalyst 4-dimethylaminopyridine, aniline can react with styrene maleic anhydride copolymer to prepare styrene-N-phenylmaleimide copolymer. The prepared polymer has less residual anhydride content in the main chain, high product thermal stability, and a relatively high glass transition temperature, improving the heat resistance of ABS. It is speculated that the possible reason is that there is an electron-donating structure in 4-dimethylaminopyridine, which resonates with the pyridine ring and can activate the nitrogen atom on the ring to undergo a substitution reaction, having a significant catalytic effect on the acylation of styrene maleic anhydride copolymer, causing the maleic anhydride on the main chain to undergo an acylation reaction to form maleimide, reducing the residual amount of maleic anhydride on the main chain, and increasing the reaction conversion rate of the polymer. In this application, using a styrene maleic anhydride copolymer with a weight ratio of styrene to maleic anhydride of (1 - 4):1 can further avoid the residual of unreacted maleic anhydride on the main chain, and at the same time can increase the conversion rate of styrene-N-phenylmaleimide copolymer, increase the glass transition temperature of the polymer, and improve the heat resistance when applied to ABS.

[0015] As a preferred embodiment, the glass transition temperature of the polymer is 175 - 205 °C.

[0016] As a preferred embodiment, the glass transition temperature of the polymer is 190 °C.

[0017] The second aspect of the present invention provides a method for preparing a polymer for increasing the heat distortion temperature of ABS, comprising the following steps:

[0018] (1) Add an aniline compound to a reaction kettle and heat to 80 - 120 °C;

[0019] (2) Subsequently, slowly add a styrene maleic anhydride copolymer and stir to dissolve;

[0020] (3) Finally, add a catalyst and stir evenly, raise the temperature to 120 - 180 °C, react for 1 - 2 h, perform devolatilization treatment to remove unreacted aniline, and discharge to obtain the product.

[0021] As a preferred embodiment, the method of the devolatilization treatment is selected from one of strand devolatilization, thin-film devolatilization, and screw devolatilization.

[0022] As a preferred embodiment, the method of the devolatilization treatment is strand devolatilization.

[0023] As a preferred embodiment, the temperature of the devolatilization treatment is 250 - 350 °C, and the absolute pressure of the devolatilization treatment is 1 - 20 KPa.

[0024] As a preferred embodiment, the temperature of the devolatilization treatment is 300 - 320 °C, and the absolute pressure of the devolatilization treatment is 4 - 10 KPa.

[0025] As a preferred embodiment, when the polymer for increasing the heat distortion temperature of ABS is used, it needs to be blended with ABS, and the weight ratio of the polymer to ABS is 1:(3 - 5); preferably, the weight ratio of the polymer to ABS is 1:4.

[0026] As a preferred embodiment, the method for using the polymer for increasing the heat distortion temperature of ABS in ABS comprises the following steps: after blending the polymer with ABS, extrude and pelletize through a twin-screw extruder, the extrusion temperature is 230 - 260 °C, and then test the properties of the modified ABS by injection molding through an injection molding machine, and the injection molding temperature is 240 - 260 °C.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) For the polymer for increasing the heat distortion temperature of ABS in the present invention, by using a styrene maleic anhydride copolymer with a weight ratio of styrene to maleic anhydride of (1 - 4):1 to first carry out an imidization reaction with aniline and then polymerization, the conversion rate of maleimide is increased, and the residue of maleic anhydride on the main chain is reduced.

[0029] (2) The polymer for increasing the heat distortion temperature of ABS, by using 4-dimethylaminopyridine as a catalyst, enables the preparation of styrene-N-phenylmaleimide polymer at a lower reaction temperature and within a shorter reaction time, improving production efficiency and reducing energy consumption.

[0030] (3) The polymer for increasing the heat distortion temperature of ABS, by blending with ABS at a weight ratio of 1:4, increases the heat distortion temperature and Vicat softening point of ABS. And due to the low residual amount of maleic anhydride on the main chain, it has good compatibility and better mechanical properties after blending with ABS. Detailed implementation manners

[0031] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention above still fall within the protection scope of the present invention.

[0032] In addition, if there is no other description, the raw materials used are commercially available.

[0033] Example 1

[0034] A polymer for increasing the heat distortion temperature of ABS, the preparation raw materials include, by weight: 45 parts of styrene maleic anhydride copolymer, 60 parts of aniline compound, and 1 part of catalyst.

[0035] The weight-average molecular weight of the styrene maleic anhydride copolymer is 120,000, and the molar ratio of styrene to maleic anhydride in the styrene maleic anhydride copolymer is 2:1, purchased from Jiaxing Huawei Chemical Co., Ltd.

[0036] The aniline compound is p-toluidine.

[0037] The catalyst is 4-dimethylaminopyridine.

[0038] A preparation method of a polymer for increasing the heat distortion temperature of ABS, comprising the following steps:

[0039] (1) Add the aniline compound into a reaction kettle and heat to 120 °C;

[0040] (2) Subsequently, slowly add the styrene maleic anhydride copolymer and stir to dissolve;

[0041] (3) Finally, add the catalyst and stir evenly, raise the temperature to 160 °C, react for 1.5 h, perform devolatilization treatment to remove unreacted aniline, and discharge to obtain the product.

[0042] The devolatilization treatment method is strip devolatilization, the temperature of the devolatilization treatment is 320 °C, and the absolute pressure of the devolatilization treatment is 6 KPa.

[0043] Performance Test

[0044] The polymer prepared in Example 1 for improving the heat distortion temperature of ABS was blended with ABS. The weight ratio of the polymer to ABS was 1:4. Granulation was carried out by extrusion through a twin-screw extruder at an extrusion temperature of 245 °C. Then, test specimens were injection-molded by an injection molding machine to test the performance of the modified ABS at an injection temperature of 250 °C. The ABS was purchased from Chi Mei Chemical Industry Co., Ltd. and the model was PA-757K.

[0045] 1. Tensile strength: The tensile strength of the modified ABS was tested according to the ASTM D638-91 standard, and the test condition was 50 mm / min.

[0046] 2. Flexural strength: The flexural strength of the modified ABS was tested according to the ASTM D790-10 standard, and the test condition was 2 mm / min.

[0047] 3. Flexural modulus: The flexural strength of the modified ABS was tested according to the ASTM D790-10 standard, and the test condition was 2 mm / min.

[0048] 4. Notched impact strength: The notched impact strength of the modified ABS was tested according to the ASTM D256-2010E standard, the test temperature was 23 °C, and the notches were 1 / 8 notch and 1 / 4 notch.

[0049] 5. Density: The density of the modified ABS was tested according to the ASTM D 792-00 standard.

[0050] 6. Melt index: The melt index of the modified ABS was tested according to the ASTM D1238-2004 standard, and the test condition was 220 °C / 10 kg.

[0051] 7. Heat distortion temperature: The heat distortion temperature of the modified ABS was tested according to the ASTM D 648-01 standard, and the test condition was 1.82 MPa.

[0052] 8. Vicat softening point: The Vicat softening point of the modified ABS was tested according to the ASTM D1525-07 standard, and the test condition was 50 N.

[0053] The modified ABS and the unmodified ABS were tested, and the test results are shown in Table 1.

[0054] Table 1

[0055]

Claims

1. A polymer for improving the heat distortion temperature of ABS, characterized in that The raw materials for preparation include, by weight: 25-50 parts of styrene maleic anhydride copolymer, 50-75 parts of aniline compound, and 0.1-2 parts of catalyst; The weight-average molecular weight of the styrene maleic anhydride copolymer is 20,000; The molar ratio of styrene to maleic anhydride in the styrene maleic anhydride copolymer is (1-4):1; The catalyst is 4-dimethylaminopyridine.

2. The polymer for increasing the heat distortion temperature of ABS according to claim 1, wherein The amino substituents in the aniline compound are selected from one or a combination of several of amino, imino, and tertiary amino.

3. The polymer for increasing the heat distortion temperature of ABS according to claim 1 or 2, characterized in that, The aniline compound is selected from one or a combination of several of aminobenzene, p-toluidine, o-toluidine, m-toluidine, dimethylaniline, and N-methylaniline.

4. The polymer for increasing the heat distortion temperature of ABS according to claim 1, characterized in that, The glass transition temperature of the polymer is 175-205 °C.

5. A method for preparing a polymer for increasing the heat distortion temperature of ABS according to any one of claims 1-4, characterized in that, It includes the following steps: (1) Add the aniline compound to the reaction kettle and heat to 80-120 °C; (2) Then slowly add the styrene maleic anhydride copolymer and stir to dissolve; (3) Finally, add the catalyst and stir evenly, heat up to 120-180 °C, react for 1-2 h, perform devolatilization treatment to remove the unreacted aniline, and discharge to obtain the product.

6. The preparation method of the polymer for increasing the heat distortion temperature of ABS according to claim 5, characterized in that, The method of the devolatilization treatment is selected from one of falling-strip devolatilization, thin-film devolatilization, and screw devolatilization.

7. The preparation method of the polymer for increasing the heat distortion temperature of ABS according to claim 5, characterized in that, The temperature of the devolatilization treatment is 250-350 °C, and the absolute pressure of the devolatilization treatment is 1-20 KPa.

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