High-temperature-resistant engineering plastic and preparation method thereof

Abstract

The invention relates to high-temperature-resistant engineering plastic and a preparation method thereof, and belongs to the technical field of engineering plastic preparation. The material comprises the following raw materials: a PBT base material, modified polyarylester, ceramic fibers and a lubricant, the modified polyarylester is prepared by carrying out melt polymerization on acetylated bisphenol monomer and dicarboxyl monomer; the dicarboxyl monomer is prepared from a coupling product through an oxidation reaction, the coupling reaction product is prepared from a substitution reaction product and m-fluorotoluene through a reaction, and the substitution reaction product is prepared through a Williamson reaction of 4-hydroxybenzaldehyde and (3-chloropropyl) triethoxysilane. And modified polyarylester is introduced. The modified polyarylester is a thermotropic main chain type liquid crystal polymer, the PBT is subjected to toughening modification by utilizing the liquid crystal performance of the modified polyarylester, a molecular chain of the modified polyarylester contains a siloxane flexible chain, and the problem of poor water resistance of the PBT can be solved by introducing a side chain.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering plastics preparation, and specifically relates to a high-temperature resistant engineering plastic and a preparation method thereof. Background Art

[0002] Engineering plastics are plastic parts supported by high molecular polymers or traditional rubbers. Due to their strong mechanical properties at high temperatures, they can rival metal parts, so the parts made of them can replace metals in manufacturing machine parts. Moreover, the parts made of engineering plastics have advantages that the machine parts made of metals cannot achieve, such as insulation and corrosion resistance. For example, polybutylene terephthalate (PBT) has excellent high insulation and heat resistance, and is commonly used in the electronics, electrical and automotive industries. However, its strength and stiffness are relatively low. When it is applied, fillers are usually added to improve its strength and stiffness to meet the application environment of engineering plastics. Moreover, problems such as poor hydrolysis resistance and poor toughness are found.

[0003] Therefore, it is necessary to modify PBT engineering plastics to broaden their application scope. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide a high-temperature resistant engineering plastic and a preparation method thereof.

[0005] The first object of the present invention can be achieved by the following technical solutions: A high-temperature resistant engineering plastic, comprising the following raw materials in parts by weight: 80 - 100 parts of PBT base material, 25 - 65 parts of modified polyarylate, 15 - 30 parts of ceramic fiber, and 1 - 3 parts of lubricant; The modified polyarylate is prepared by melt polymerization of acetylated bisphenol monomers and dicarboxylic acid monomers; The dicarboxylic acid monomer is prepared by oxidation reaction of a coupling product, the coupling reaction product is prepared by reaction of a substitution reaction product and m-fluorotoluene, and the substitution reaction is a Williamson reaction between 4-hydroxybenzaldehyde and (3-chloropropyl)triethoxysilane.

[0006] Furthermore, the molar ratio of the bisphenol monomer to the dicarboxylic acid monomer is 2 - 3:1 - 2.

[0007] Furthermore, the melt polymerization reaction of the acetylated bisphenol monomer and the dicarboxylic acid monomer includes: Under a nitrogen atmosphere and with stirring, the acetylated bisphenol monomer, the first catalyst, and the dicarboxylic acid monomer are heated and melted and mixed, stirred at 180 - 220 °C for 1 - 2 h, then the temperature is raised to 280 - 330 °C and stirred for 1 - 4 h. Stop passing nitrogen, evacuate, and react at a vacuum degree of -0.03 to -0.1 MPa for 20 - 40 min to obtain the modified polyarylate.

[0008] Further, the first catalyst is zinc acetate or magnesium acetate.

[0009] Further, the preparation of the dicarboxylic acid monomer includes: Mix 4-hydroxybenzaldehyde, (3-chloropropyl)triethoxysilane, potassium carbonate (absorbing hydrogen ions), potassium iodide (catalyst), and dimethyl sulfoxide evenly, then heat to 80 - 100 °C, keep warm and stir for reaction for 6 - 12 h (Williamson reaction occurs), and obtain the substitution reaction product through post-treatment; Mix the substitution reaction product, m-fluorotoluene, thioglycolic acid (as a catalyst), and dimethyl sulfoxide evenly, then heat to 70 - 115 °C, keep warm and stir for reaction for 6 - 12 h, and obtain the coupling reaction product through post-treatment; Drop the pyridine solution of the coupling reaction product into the potassium permanganate solution, heat to reflux, stir for reaction under reflux for 4 - 12 h, and obtain the dicarboxylic acid monomer through post-treatment.

[0010] The molecular structural formula of the dicarboxylic acid monomer is shown as follows.

[0011]

[0012] Further, the molar ratio of 4-hydroxybenzaldehyde to (3-chloropropyl)triethoxysilane is 1:1 - 1.5.

[0013] Further, the molar ratio of 4-hydroxybenzaldehyde to m-fluorotoluene is 1:2 - 2.5.

[0014] Further, the molar ratio of m-fluorotoluene to potassium permanganate is 1:1.5 - 4.

[0015] Further, the bisphenol monomer is 4,4'-dihydroxyazobenzene.

[0016] Further, the lubricant is a lubricant well-known in the technical field of the present invention, and the present invention does not make a special limitation.

[0017] The second object of the present invention can be achieved by the following technical solution: A preparation method of a high-temperature resistant engineering plastic, including: Mix the PBT base material, the modified polyarylate, the ceramic fiber, and the lubricant evenly to obtain the first mixture; After melting and blending the first mixture and ceramic fibers, followed by extrusion and pelletization, a high-temperature resistant engineering plastic is obtained.

[0018] Furthermore, the mixing temperature when the PBT base material, modified polyarylate, ceramic fibers, and lubricant are mixed is 100 - 110 °C.

[0019] Furthermore, the extrusion temperature is 265 - 185 °C.

[0020] Advantages of the present invention: The high-temperature resistant engineering plastic and its preparation method provided by the present invention address the problems of poor water resistance and poor toughness of PBT-based engineering plastics by introducing modified polyarylate. Among them, the modified polyarylate is a thermotropic main-chain liquid crystal polymer (its main chain is composed of repeated azobenzene methyl ester groups, methylene groups, and benzyl ester groups. Among them, the azobenzene group and the benzyl ester group are rigid groups, and the main chain has a high degree of regularity and rigidity). Utilizing its liquid crystal properties, the toughness of PBT is modified. Moreover, the molecular chain of the modified polyarylate contains a siloxane flexible chain (the introduction of the side chain improves the processing performance of the modified polyarylate). At the same time, the introduction of the side chain can also improve the problem of poor water resistance of PBT. Specific embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0022] Example 1

[0023] Dicarboxyl monomer: 1. After uniformly mixing 0.1 mol of 4-hydroxybenzaldehyde, 0.12 mol of (3-chloropropyl)triethoxysilane, 0.1 mol of potassium carbonate (absorbing hydrogen ions), 2 g of potassium iodide (catalyst), and 150 mL of dimethyl sulfoxide, heat to 90 °C, keep stirring and reacting for 8 h. Pour the reaction solution into deionized water, place it at 5 °C for aging precipitation, filter, and repeatedly wash the filter cake to obtain the substitution reaction product; 2. After uniformly mixing the substitution reaction product obtained in step 1, 0.23 mol of m-fluorotoluene, 2.5 g of mercaptoacetic acid (as a catalyst), and 150 mL of dimethyl sulfoxide, heat to 95 °C, keep stirring and reacting for 8 h. Pour the reaction solution into deionized water, place it at 5 °C for aging, filter, and repeatedly wash the filter cake to obtain the coupling reaction product; 3. Add 100 mL of the pyridine solution containing the coupling reaction product prepared in Step 2 dropwise to 100 mL of a potassium permanganate solution (containing 40 g of potassium permanganate), heat to reflux, stir the reaction for 4 h under reflux, filter by suction at room temperature, distill the mother liquor to recover pyridine, precipitate with dilute hydrochloric acid, filter, wash the filter cake, and dry to obtain the dicarboxyl monomer.

[0024] Example 2

[0025] Dicarboxyl monomer: 1. Mix 0.1 mol of 4-hydroxybenzaldehyde, 0.15 mol of (3-chloropropyl)triethoxysilane, 0.1 mol of potassium carbonate (to absorb hydrogen ions), 2 g of potassium iodide (catalyst), and 150 mL of dimethyl sulfoxide evenly, heat to 100 °C, keep stirring and reacting for 6 h, pour the reaction solution into deionized water, place it at 5 °C for aging and precipitation, filter, and wash the filter cake repeatedly to obtain the substitution reaction product; 2. Mix the substitution reaction product obtained in Step 1, 0.25 mol of m-fluorotoluene, 2.5 g of mercaptoacetic acid (as a catalyst), and 150 mL of dimethyl sulfoxide evenly, heat to 115 °C, keep stirring and reacting for h, pour the reaction solution into deionized water, place it at 5 °C for aging, filter, and wash the filter cake repeatedly to obtain the coupling reaction product; 3. Add 100 mL of the pyridine solution containing the coupling reaction product prepared in Step 2 dropwise to 100 mL of a potassium permanganate solution (containing 40 g of potassium permanganate), heat to reflux, stir the reaction for 12 h under reflux, filter by suction at room temperature, distill the mother liquor to recover pyridine, precipitate with dilute hydrochloric acid, filter, wash the filter cake, and dry to obtain the dicarboxyl monomer.

[0026] Example 3

[0027] Modified polyarylate: 1. Mix 4,4'-dihydroxyazobenzene with 4 times the amount of acetic anhydride, stir and heat to dissolve 4,4'-dihydroxyazobenzene at 85 °C, then add a few drops of concentrated sulfuric acid (mass fraction 98%), and then heat to reflux and react for 4 h. Stop heating, pour it into ice water while it is hot to precipitate, age, filter, wash the filter cake, and dry to obtain acetylated 4,4'-dihydroxyazobenzene; 2. Under a nitrogen atmosphere and with stirring, heat and melt and mix 0.2 mol of acetylated 4,4'-dihydroxyazobenzene, zinc acetate, and 0.1 mol of the dicarboxyl monomer prepared in Example 1, stir at 180 °C for 1 - 2 h, then raise the temperature to 280 °C and stir for 2 h. Stop passing nitrogen, evacuate, react at a vacuum degree of -0.03 MPa for 30 min, and cool to room temperature to obtain the modified polyarylate.

[0028] Example 4

[0029] Modified polyarylate: 1. Mix 4,4'-dihydroxyazobenzene with 4 times the amount of acetic anhydride, stir and heat at 85 °C until 4,4'-dihydroxyazobenzene dissolves. Then add a few drops of concentrated sulfuric acid (mass fraction 98%), and then heat under reflux for 4 h. Stop heating, pour it into ice water while it is still hot to precipitate, age, filter, wash and dry the filter cake to obtain acetylated 4,4'-dihydroxyazobenzene; 2. Under a nitrogen atmosphere and with stirring, melt and mix 0.3 mol of acetylated 4,4'-dihydroxyazobenzene, magnesium acid inhibitor and 0.2 mol of the dicarboxylic acid monomer prepared in Example 1, stir at 190 °C for 1 - 2 h, then raise the temperature to 290 °C and stir for 2 h. Stop passing nitrogen, evacuate, react at a vacuum degree of -0.1 MPa for 20 min, and cool to room temperature to obtain the modified polyarylate.

[0030] Comparative Example 1 Dicarboxylic acid monomer: 1. Mix 0.1 mol of benzaldehyde, 0.23 mol of m-fluorotoluene, 2.5 g of thioglycolic acid and 150 mL of dimethyl sulfoxide evenly, heat to 95 °C, keep stirring and reacting for 8 h. Pour the reaction solution into deionized water, place it at 5 °C for aging, filter, and wash the filter cake repeatedly to obtain the coupling reaction product; 2. Drop 100 mL of the pyridine solution containing the coupling reaction product prepared in Step 1 into 100 mL of potassium permanganate solution (containing 40 g of potassium permanganate), heat to reflux, stir and react under reflux for 4 h, filter at room temperature, distill and recover pyridine from the mother liquor, precipitate with dilute hydrochloric acid, filter, wash and dry the filter cake to obtain the dicarboxylic acid monomer.

[0031] Comparative Example 2 Polyarylate: Under a nitrogen atmosphere and with stirring, melt and mix the acetylated bisphenol monomer, zinc acetate and the dicarboxylic acid monomer prepared in Comparative Example 1, stir at 180 °C for 1 - 2 h, then raise the temperature to 280 °C and stir for 2 h. Stop passing nitrogen, evacuate, react at a vacuum degree of -0.03 MPa for 30 min, and cool to room temperature to obtain the polyarylate.

[0032] Example 5

[0033] Engineering plastic: 1. Prepare raw materials including the following parts by weight: 100 parts of PBT base material, 25 parts of the modified polyarylate prepared in Example 1, 30 parts of ceramic fiber, and 3 parts of lubricant (polyethylene wax); 2. Mix the PBT base material, modified polyarylate, ceramic fiber and lubricant evenly to obtain the first mixture; After melting and blending the first mixture and ceramic fibers, followed by extrusion and pelletization, a high-temperature resistant engineering plastic is obtained. The mixing temperature when the PBT base material, modified polyarylate, ceramic fibers, and lubricant are mixed is 100 - 110°C, and the extrusion temperature is 265 - 185°C.

[0034] Example 6

[0035] Engineering plastic: 1. Prepare raw materials including the following parts by weight: 90 parts of PBT base material, 45 parts of the modified polyarylate prepared in Example 2, 20 parts of ceramic fibers, and 1 part of lubricant (polyethylene wax); 2. Mix the PBT base material, modified polyarylate, ceramic fibers, and lubricant evenly to obtain a first mixture; After melting and blending the first mixture and ceramic fibers, followed by extrusion and pelletization, a high-temperature resistant engineering plastic is obtained. The mixing temperature when the PBT base material, modified polyarylate, ceramic fibers, and lubricant are mixed is 100 - 110°C, and the extrusion temperature is 265 - 185°C.

[0036] Example 7

[0037] Engineering plastic: 1. Prepare raw materials including the following parts by weight: 80 parts of PBT base material, 50 parts of the modified polyarylate prepared in Example 1, 15 parts of ceramic fibers, and 3 parts of lubricant (polyethylene wax); 2. Mix the PBT base material, modified polyarylate, ceramic fibers, and lubricant evenly to obtain a first mixture; After melting and blending the first mixture and ceramic fibers, followed by extrusion and pelletization, a high-temperature resistant engineering plastic is obtained. The mixing temperature when the PBT base material, modified polyarylate, ceramic fibers, and lubricant are mixed is 100 - 110°C, and the extrusion temperature is 265 - 185°C Comparative Example 3 Engineering plastic: Compared with Example 5, the equivalent parts of the modified polyarylate in the raw materials are replaced with the polyarylate prepared in Comparative Example 2, and the rest are the same.

[0038] Comparative Example 4 Engineering plastic: Compared with Example 5, the modified polyarylate in the raw materials is deleted, and the rest are the same.

[0039] Perform physical property tests on the engineering plastics obtained in Examples 5 - 7 and Comparative Examples 3 - 4. The obtained results are shown in Table 1 in detail.

[0040] Table 1

[0041] It can be seen from the data in Table 1 that the engineering plastics obtained in Examples 5 - 7 of the present invention have good high-temperature resistance, water resistance, and toughness.

[0042] In the description of the specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0043] The above content is only an example and explanation of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high temperature resistant engineering plastic, characterized in that: The method comprises the following raw materials in parts by weight: 80-100 parts of PBT base material, 25-65 parts of modified polyarylate, 15-30 parts of ceramic fiber, and 1-3 parts of lubricant; The modified polyarylate is prepared by melt polymerization of acetylated bisphenol monomer and dicarboxyl monomer; The dicarboxyl monomer is prepared by an oxidation reaction of a coupling product, the coupling reaction product is prepared by a reaction of a substitution reaction product and m-fluorotoluene, and the substitution reaction is prepared by a Williamson reaction of 4-hydroxybenzaldehyde and (3-chloropropyl)triethoxysilane.

2. A high temperature resistant engineering plastic according to claim 1, characterized in that: The molar ratio of the bisphenol monomer to the dicarboxyl monomer is 2-3:1-2.

3. The high temperature resistant engineering plastic according to claim 1, characterized in that: The melt polymerization reaction of the acetylated bisphenol monomer and the dicarboxyl monomer comprises: In a nitrogen atmosphere, the acetylated bisphenol monomer, the first catalyst and the dicarboxyl monomer are heated, melted and mixed, stirred at 180-220° C. for 1-2 hours, then heated to 280-330° C. and stirred for 1-4 hours, the nitrogen flow is stopped, vacuum is drawn, and the reaction is carried out at a vacuum degree of -0.03~-0.1MPa for 20-40 minutes to obtain a modified polyarylate.

4. A high temperature resistant engineering plastic according to claim 3, characterized in that: The first catalyst is zinc acetate or magnesium acetate.

5. The high temperature resistant engineering plastic according to claim 1, characterized in that: The preparation of the dicarboxyl monomer comprises: After 4-hydroxybenzaldehyde, (3-chloropropyl)triethoxysilane, potassium carbonate, potassium iodide and dimethyl sulfoxide are uniformly mixed, heated to 80-100°C, stirred and reacted for 6-12 hours, and post-treated to obtain a substitution reaction product; The substitution reaction product, m-fluorotoluene, thioacetic acid and dimethyl sulfoxide are mixed evenly, heated to 70-115° C., stirred and reacted for 6-12 hours, and post-treated to obtain a coupling reaction product; The pyridine solution of the coupling reaction product is added dropwise to the potassium permanganate solution, heated to reflux, stirred and reacted under reflux for 4-12 hours, and post-treated to obtain a dicarboxyl monomer.

6. A high temperature resistant engineering plastic according to claim 5, characterized in that: The molar ratio of the 4-hydroxybenzaldehyde to (3-chloropropyl)triethoxysilane is 1:1-1.

5.

7. The high temperature resistant engineering plastic according to claim 5, characterized in that: The molar ratio of the 4-hydroxybenzaldehyde to m-fluorotoluene is 1:2-2.

5.

8. The high temperature resistant engineering plastic according to claim 5, characterized in that: The molar ratio of m-fluorotoluene to potassium permanganate is 1:1.5-4.

9. The high temperature resistant engineering plastic according to claim 1, characterized in that: The bisphenol monomer is 4,4'-dihydroxyazobenzene.

10. The method for preparing a high temperature resistant engineering plastic according to claim 1, characterized in that: include: The PBT base material, the modified polyarylate, the ceramic fiber and the lubricant are uniformly mixed to obtain a first mixture; The first mixture and the ceramic fiber are melt-blended, extruded, and granulated to obtain high-temperature resistant engineering plastics.

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