Search

CN-121991481-A - High-fluidity high-transparency PC/copolyester alloy material, and preparation method and application thereof

CN121991481ACN 121991481 ACN121991481 ACN 121991481ACN-121991481-A

Abstract

The invention discloses a high-flow high-transparency PC/copolyester alloy material, and a preparation method and application thereof, and relates to the technical field of high-molecular alloy materials. The alloy material is prepared by taking polycarbonate as a base material and blending the base material with specific modified copolyester. Meanwhile, the carboxyl end group of the functional group active monomer end-capped copolyester is added in the polymerization final polymerization stage, so that the low-carboxyl end-group low-molecular-weight copolyester resin is realized, and the carboxyl end group content is lower than 20mol/t. The modified copolyester and PC partial chain segments form a block reaction under high-temperature melt processing to form a block-type high-molecular compatible system in situ, so that the problems that the PC and the polyester are poor in blending compatibility and difficult to consider the fluidity, optical performance, mechanical performance and chemical cracking resistance in the prior art are solved, the low-molecular-weight copolyester is well dispersed in a high-viscosity PC system, and the formed alloy material has good melt fluidity, optical transparency, proper mechanical performance and enhanced chemical cracking resistance.

Inventors

  • JIANG HONGLIANG
  • ZHANG WEIWEI
  • ZOU XIANGPING
  • TIAN HONGCHI
  • YANG PENGFEI
  • Fan Shaoji

Assignees

  • 山东道恩合复新材料有限公司
  • 道恩高分子材料(重庆)有限公司

Dates

Publication Date
20260508
Application Date
20260324

Claims (10)

  1. 1. The high-fluidity high-transparency PC/copolyester alloy material is characterized by comprising, by mass, 70-90 parts of a main phase resin PC, 10-30 parts of a disperse phase resin, 0.1-0.4 part of an antioxidant and 0.1-0.3 part of a lubricant; wherein the disperse phase resin is copolyester modified by a polyfunctional active monomer; the dispersed phase resin has the following characteristics: the carboxyl end group content is less than or equal to 20mol/t, the characteristic viscosity is 0.45-0.55 dL/g, the number average molecular weight is 10000-16000, the polarity index is less than or equal to 22.9MPa 1/2 , the affinity index difference with PC resin is less than or equal to 2.4MPa 1/2 , the notch impact strength is less than or equal to 2kJ/m < 2 >, and the dispersity index DS is less than or equal to 2.27.
  2. 2. The high-flow high-transparency PC/copolyester alloy material according to claim 1, wherein PC is bisphenol A type polycarbonate, the melt index at 300 ℃ and 1.2 kg is 5-40 g/10 min, and the number average molecular weight is 18000-30000.
  3. 3. The high flow high transparency PC/copolyester alloy material according to claim 1, wherein the multifunctional reactive monomer comprises an epoxy-containing compound comprising one or more of bisphenol A epoxy resin, epoxidized soybean oil, and glycidyl ether.
  4. 4. The high-fluidity high-transparency PC/copolyester alloy material according to claim 3, wherein the addition amount of the multifunctional reactive monomer is 0.3% -0.8% of the total mass of the copolyester.
  5. 5. The high-fluidity high-transparency PC/copolyester alloy material according to claim 1, wherein the antioxidant is obtained by mixing a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1:1-2:1, and the lubricant comprises one or more of pentaerythritol stearate, vinyl bis-stearamide, zinc stearate, stearic acid and rice bran wax.
  6. 6. The method for preparing a high-fluidity high-transparency PC/copolyester alloy material according to any one of claims 1 to 5, characterized by comprising, Adding PTA, ethylene glycol and a low-polarity third monomer into a polymerization reaction kettle, sequentially carrying out esterification reaction, pre-polycondensation reaction and final polymerization reaction, adding a multifunctional active monomer 10-40 min before the final polymerization reaction is finished, and continuing to react to a terminal point to obtain modified copolyester; Uniformly mixing PC, modified copolyester, an antioxidant and a lubricant according to mass parts, and putting into a double-screw extruder for melt blending, extrusion and granulation to obtain a PC/copolyester alloy material; The processing temperature of the double-screw extruder is 220-260 ℃, and the screw rotating speed is 180-250 r/min.
  7. 7. The method of claim 6, wherein the modified copolyester has an alkyd mole ratio of ethylene glycol to PTA of 0.35-0.75:1 and a mole ratio of low polarity third monomer to PTA of 0.25-0.6:1.
  8. 8. The method of claim 7 wherein the low polarity third monomer is a diol having an alicyclic structure or a long chain alkyl structure, and is selected from one or more of 1, 4-cyclohexanedimethanol, 2-methyl-1, 3-propanediol, neopentyl glycol, 1, 5-pentanediol, 2, 4-tetramethylcyclobutane dimethanol.
  9. 9. The method for preparing the high-fluidity high-transparency PC/copolyester alloy material according to claim 6, wherein the esterification reaction is carried out at a temperature of 230-250 ℃, a pressure of 0.2-0.4 MPa and a reaction time of 2-4 hours, the pre-polycondensation reaction is carried out at a temperature of 240-270 ℃, a pressure of 200-1000 Pa and a reaction time of 1-2 hours, and the final polymerization reaction is carried out at a temperature of 250-280 ℃, a pressure of 20-100 Pa and a reaction time of 1-3 hours.
  10. 10. An application of the PC/copolyester alloy material according to any one of claims 1 to 5 in the fields of electronic and electric appliance shells, medical appliances, food packaging and optical lenses.

Description

High-fluidity high-transparency PC/copolyester alloy material, and preparation method and application thereof Technical Field The invention belongs to the technical field of high polymer alloy materials, and particularly relates to a high-flow high-transparency PC/copolyester alloy material, and a preparation method and application thereof. Background Polycarbonate (PC) is an engineering plastic with excellent performance, high impact strength, good heat resistance and optical transparency, and is widely applied to the fields of electronic appliances, automobiles, medical appliances, optical products and the like. However, the high steric hindrance molecular structure of PC resin causes the defects of poor melt fluidity, high processing difficulty, poor chemical corrosion resistance and the like, and limits the application of PC resin in some high-end thin-wall and complex structure products. In order to improve the processability and chemical resistance of PC, researchers try to blend and modify PC with various polyesters to prepare PC/polyester alloy materials. Polyester materials such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like have good melt fluidity and chemical resistance, but have extremely poor compatibility due to the fact that stronger polar bonds and hydrogen bonds exist in a molecular structure and the polarity difference between the polyester materials and PC (bisphenol A structure and low polarity affinity) is large, and the optical transparency and mechanical properties of the alloy materials are seriously reduced after blending, so that the actual application requirements are difficult to meet. Copolyesters PETG (polyethylene terephthalate-1, 4-cyclohexanedimethanol ester) and PCTG (polycyclocyclohexanedimethanol-ethylene terephthalate) are polyester materials modified by copolymerization of a third monomer, and the alicyclic structure in the molecular structure of the polyester materials can adjust the polarity of the materials, so that the polyester materials have the potential of improving compatibility with PC in theory. However, in the prior art, the blending research of PETG/PCTG and PC still has a plurality of problems that in the traditional PETG/PCTG preparation process, in order to ensure the mechanical strength, the characteristic viscosity is generally controlled to be more than 0.65dL/g, the number average molecular weight is about 20000, the compatibility with PC is still poor, the transparency and the fluidity of the alloy material are difficult to be compatible after blending, if the viscosity and the molecular weight of the PETG/PCTG are reduced to improve the compatibility, the mechanical property of the alloy material is greatly reduced, the content of terminal carboxyl is obviously increased, and is generally more than 60 mol/t), and the hydrolytic aging of the material in the processing and using processes is aggravated by the existence of the terminal carboxyl, so that the material performance is further worsened. In addition, although attempts are made in the prior art to improve the compatibility of PC and polyester by adding a compatibilizer, a small molecular compatibilizer or a conventional graft copolymer is often adopted, and even dispersion of the copolyester in a high-viscosity PC system is difficult to realize. The core problem is that the design of a precise compatibility mechanism aiming at a PC/copolyester system is lacking, and the high transparency, the high flow and the excellent mechanical property cannot be simultaneously considered. Therefore, how to prepare a copolyester which is not only well compatible with PC, but also has high fluidity, high transparency, excellent mechanical property and chemical cracking resistance through a molecular structure design and a compatibility mechanism, so as to obtain a high-performance PC/copolyester alloy material becomes a technical problem to be solved in the current field. Disclosure of Invention The present invention has been made in view of the above and/or problems occurring in the prior art. It is therefore an object of the present invention to provide a high flow high transparency PC/copolyester alloy material. The invention realizes a certain match with the polarity of PC by regulating the polarity of the copolyester, innovates a block grafting compatibility mechanism of a polyfunctional active monomer, utilizes a terminal carboxyl formed by PC chain scission under high shear to construct a block high polymer compatilizer in situ, realizes good dispersion of low molecular weight copolyester in a high viscosity PC system, solves the problems of poor dispersibility and insufficient mechanical property of the traditional copolyester by the synergistic effect of the polarity regulation and the block grafting and the molecular weight control, and finally realizes the synergistic balance of the multiple properties, particularly transparency, flow property and mechanical p