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CN-122011348-A - Hydrolysis-resistant crystallizable copolyester material, and preparation method and application thereof

CN122011348ACN 122011348 ACN122011348 ACN 122011348ACN-122011348-A

Abstract

The invention discloses a hydrolysis-resistant crystallizable copolyester material, and a preparation method and application thereof, and belongs to the technical field of high polymer copolymerization modification. Aims at solving the pain point of poor hydrolysis resistance of the traditional PET. The copolyester material is prepared by introducing 1, 4-Cyclohexanedimethanol (CHDM) as a high-steric-hindrance hydrolysis-resistant monomer aiming at chain segments of terephthalic acid (PTA) -Ethylene Glycol (EG) to form a ternary prepolymer, then copolymerizing the ternary prepolymer with a prepolymer of PTA and 1, 5-pentanediol (NG) to form a novel copolymer, and finally carrying out end-capping stabilization on active hydroxyl and carboxyl of the copolyester in a final polymerization stage. The preparation method adopts the double esterification-prepolymerization-mixed polycondensation-post end capping process, and the obtained copolyester material has excellent hydrolysis resistance, good crystallization capacity and mechanical property, and can be applied to the fields of hydrolysis-resistant textile fibers (spinning field), medical instruments and engineering plastics.

Inventors

  • ZHANG JIANRONG
  • LI QIAOLING
  • CHEN FENG

Assignees

  • 氧倍加新材料科技(金华)有限公司

Dates

Publication Date
20260512
Application Date
20260320

Claims (10)

  1. 1. A hydrolysis-resistant crystallizable copolyester material is characterized in that the copolyester material takes ethylene terephthalate as a main chain segment, and has the structural formula: R'-NHCOO-[(PTA-EG) m1 -(PTA-CHDM) n -(PTA-EG) m2 ] Q -(PTA-NG) P -OOC-NH-R" wherein R 'comprises an HMDI residue, an IPDI residue, and R' comprises an HMDI residue, an IPDI residue; the HMDI residue has the general formula , The general formula of the IPDI residue is ; PTA-EG is an ethylene terephthalate unit, ; PTA-NG neopentyl glycol terephthalate units, ; PTA-CHDM is a terephthalic acid-cyclohexanedimethanol unit, ; M1, m2, n, P and Q are integers, the value range of m1 and m2 is 1-5, the value range of m1+m2 is 4-10, the value range of n is 1-3, the value range of P is 20-50, and the value range of Q is 20-50.
  2. 2. The hydrolysis-resistant and crystallizable copolyester material according to claim 1, wherein the copolyester material has the properties of 0.65-0.85 dL/g intrinsic viscosity, 20-35% crystallinity, 235-250 ℃ melting temperature, 50MPa or more breaking strength, 80% or more intrinsic viscosity retention and 80% or more breaking strength retention after accelerated aging for 48 hours at 121 ℃/2.0MPa PCT hydrolysis resistance.
  3. 3. A process for preparing hydrolysis-resistant crystallizable copolyester material according to claim 1 or 2, which comprises the steps of using a double esterification-prepolymerization-mixed polycondensation-post-end capping process, Mixing PTA, EG, CHDM, a polyester catalyst and a stabilizer for one-time esterification until the esterification rate is more than or equal to 92% to obtain a ternary esterification product, heating for prepolymerization to obtain PTA-EG-CHDM ternary prepolymer, and marking the PTA-EG-CHDM ternary prepolymer as a prepolymer A; mixing PTA, NG and a polyester catalyst with a stabilizer for secondary esterification until the esterification rate is more than or equal to 92% to obtain PNG esterification products; Preheating and mixing a prepolymer A and a prepolymer B, gradually vacuumizing to less than or equal to 100Pa, heating to perform copolymerization reaction, injecting a capping agent when the intrinsic viscosity is more than or equal to 0.65dL/g, fully stirring for reaction, extruding and granulating a copolymer melt under nitrogen of 1-3 atm, drying to water content of less than or equal to 300ppm, and packaging to obtain a hydrolysis-resistant and crystallizable copolyester material; The copolymerization reaction is carried out in a nitrogen atmosphere, the reaction temperature is 250-270 ℃, and the reaction time is 3-5 h.
  4. 4. The method for preparing hydrolysis-resistant and crystallizable copolyester material according to claim 3, wherein the molar ratio of PTA, EG, CHDM in the PTA-EG-CHDM ternary prepolymer is 1:1-1.15:0.08-0.15, the molar ratio of PTA to NG in the PNG esterification product is 1:1.05-1.2, and the mass ratio of prepolymer A to prepolymer B is 85-95:5-15.
  5. 5. The method for preparing hydrolysis-resistant and crystallizable copolyester material according to claim 3 or 4, wherein the polyester catalyst comprises one or more of zinc acetate, cobalt acetate, tetrabutyl titanate, antimony trioxide, isopropyl titanate, antimony trioxide, ethylene glycol antimony and dibutyltin oxide, the stabilizer is a phosphorus-based compound and is selected from at least one of phosphate esters, phosphite esters and phosphonic acid compounds, wherein the phosphate esters comprise triphenyl phosphate and triethyl phosphate, the phosphite esters comprise triphenyl phosphite and distearyl pentaerythritol diphosphite, and the phosphonic acid compounds comprise 2-carboxyethyl phosphonic acid and 2-carboxypropyl phosphonic acid.
  6. 6. The method for preparing a hydrolysis-resistant and crystallizable copolyester material according to claim 5, wherein the temperature is 240-260 ℃ and the time is 1-2 h, and the vacuum degree is 1000-200 Pa.
  7. 7. The method for preparing hydrolysis-resistant and crystallizable copolyester material according to claim 3, wherein the primary esterification reaction is carried out in an inert gas atmosphere at 220-250 ℃ under 0.2-0.3 MPa for 2-4 hours, and the secondary esterification reaction is carried out in an inert gas atmosphere at 230-250 ℃ under 0.1-0.3 MPa for 3-4 hours.
  8. 8. The hydrolysis-resistant and crystallizable copolyester material according to claim 7, wherein the blocking agent is one or more selected from isophorone diisocyanate and 4,4' -dicyclohexylmethane diisocyanate, and the amount of the blocking agent is 0.4-0.9% of the mass of the copolymer.
  9. 9. The method for preparing the hydrolysis-resistant and crystallizable copolyester material according to claim 7 or 8, wherein the end capping agent is diluted and then preheated to 50-90 ℃ for injection, the end capping agent comprises one or more of diphenyl phthalate and dioctyl terephthalate, and the mixing mass ratio of the end capping agent to the diluent is 0.5-3:1.
  10. 10. Use of the hydrolysis-resistant crystallizable copolyester material according to claim 1 or 2 for the preparation of textile fibers, high-temperature sterilization packaging materials or outdoor products suitable for high-temperature and high-humidity scenes.

Description

Hydrolysis-resistant crystallizable copolyester material, and preparation method and application thereof Technical Field The invention belongs to the technical field of high polymer copolymerization modification, and particularly relates to a hydrolysis-resistant crystallizable copolyester material, and a preparation method and application thereof. Background Polyethylene terephthalate (PET) is used as a single-variety polymer material with the greatest global yield, and is widely applied to the core fields of textile fiber spinning, food packaging containers, engineering plastics and the like by virtue of excellent mechanical strength, good thermal stability and cost advantages. However, the traditional PET material has obvious technical shortboards, especially insufficient hydrolysis resistance, and severely restricts the application of the PET material under the working condition of high temperature and high humidity. The traditional PET is used for 6 months in an environment with 80 ℃ and 90% of relative humidity, the breaking strength can be reduced by more than 30%, and when the PET is used for a high-temperature sterilization packaging scene, the material is obviously embrittled and cracked after being subjected to steam sterilization for 3 times at 121 ℃. The main technical proposal of PET hydrolysis resistance in the current industry is mainly to add an anti-hydrolysis carbonization additive modification technology, and to add carbonization additives such as carbodiimide and the like to consume terminal carboxyl groups generated by PET hydrolysis and form a physical barrier so as to reduce the ester bond hydrolysis rate. CN104045980B discloses hydrolysis-resistant PET color master batch containing carbodiimide, which can reduce the content of carboxyl end by more than 60%, prolong the service life of the material by 5-8 times, and the polymerization-resistant carbodiimide hydrolysis agent developed by CN111875728a has both thermal stability and hydrolytic resistance, and can be kept stable at PET processing temperature. CN102344654B proves that the compatibility of the modified nano silicon carbide surface with PET matrix is obviously improved, and the long-term hydrolysis resistance stability is realized by the synergistic carbodiimide, but the modified nano silicon carbide is easy to generate phase separation in the processing process by an external addition mode, and is not suitable for application in occasions such as spinning films. By introducing CHDM to construct a copolyester molecular chain structure such as PETG and PCTG, the ester bond hydrolysis activity can be reduced, and the hydrolysis resistance life is prolonged by 2-3 times compared with that of the traditional PET. CN104693704a discloses a preparation technology of high transparent PETG copolyester film, by adding high efficiency ultraviolet light absorber, pigment, modified metal oxide and antioxidant, the material has a hydrolysis resistance life up to 2.8 times of PET under 85 ℃/85% rh wet heat condition. CN116693830a further demonstrates that when the molar ratio of CHDM to ethylene glycol in PCTG copolyester is 6:4, the carboxyl end group growth rate is only 1/3 of that of PET, and the service life is prolonged by 2.5 times in a 120 ℃ high pressure steam environment, but the cost is very high, and the copolymer is non-crystalline, and is not suitable for fiber or other engineering plastic applications. The prior art does not effectively solve the problem of blocking the active hydroxyl at the tail end of a molecular chain, the tail end hydroxyl and a carboxylic acid end group are taken as starting sites of hydrolysis reaction, the material degradation process can be accelerated, and the low-molecular type blocking agent is difficult to realize long-acting hydrolysis resistance due to poor heat resistance and poor blocking effect due to easy volatilization. In summary, the existing hydrolysis-resistant PET modification technology has multiple limitations that the CHDM copolymerized PETG/PCTG resin has low crystallization capability, reduced spinnability and low fiber strength, and the hydrolysis-resistant carbonization additive has the problems of poor thermal stability, gas production during processing and the like. The development of the PET composite material has excellent hydrolysis resistance, crystallinity and mechanical properties, is applied to core fields such as spinning, high-strength films and the like, becomes a technical problem to be solved urgently in the current PET industry, and has important significance in expanding the application scene of PET and improving the added value of products. Disclosure of Invention This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be