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CN-122011695-A - Degradable high-permeability polyester resin and preparation method thereof

CN122011695ACN 122011695 ACN122011695 ACN 122011695ACN-122011695-A

Abstract

The application relates to the technical field of degradable polyester, in particular to degradable high-permeability polyester resin and a preparation method thereof. The application solves the problem that the light transmittance and mechanical property of the degradable high-permeability polyester resin are difficult to be combined. By preparing a high-transmittance polyester matrix, a random structure is constructed to refine a crystal area, so that the problem of light-tightness caused by crystallization is solved; meanwhile, preparing modified nanocellulose with matched refractive index by in-situ polymerization, and introducing hyperbranched polymer into blending; in the double-screw extrusion process, a chain extender two-stage gradient feeding process is adopted, and supercritical carbon dioxide is used for reducing the processing temperature and promoting dispersion, so that the preparation method avoids thermal yellowing and gel point, and the biodegradable polyester material with high light transmittance and excellent mechanical strength is prepared through the double functions of hydrogen bond physical network and chemical crosslinking.

Inventors

  • ZHOU LIWEN
  • WANG QINGYU
  • WU ZHENGYONG
  • XIA PINGCHAO
  • HU ZHENGGUI

Assignees

  • 江苏欣宝科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260228

Claims (7)

  1. 1. The preparation method is characterized in that a high-permeability polyester matrix, an anti-hydrolysis agent and a hyperbranched polymer are uniformly mixed in a mixer to obtain a high-permeability polyester composition, the high-permeability polyester composition is added into a main feeding port of a double-screw extruder, modified nanocellulose is added into the main feeding port through a side feeding port I, supercritical carbon dioxide is injected into a sixth zone, vacuum devolatilization is carried out in an eleventh zone, and the polyester resin is obtained after water cooling and granulating; The modified nano-cellulose is obtained by coating polylactic acid chain segments on the surface of cellulose nanocrystals, and the refractive index of the modified cellulose nanocrystals is matched with that of the high-permeability polyester matrix.
  2. 2. The preparation method of the degradable high-permeability polyester resin is characterized by comprising the steps of adding succinic acid, 1, 4-butanediol, 1, 4-cyclohexanedimethanol, isosorbide and tetrabutyl titanate into a reaction kettle, heating, stirring for reaction, heating, vacuumizing, reducing the stirring rotation speed for continuous reaction, charging nitrogen, discharging, water-cooling and granulating to obtain the high-permeability polyester resin.
  3. 3. The method for preparing the degradable high-permeability polyester resin according to claim 1, wherein the preparation method of the hyperbranched polymer is characterized in that anhydrous citric acid, isophorone diamine and 1, 4-butanediol are added into a reaction kettle, the temperature is raised, the reaction is carried out under the protection of nitrogen, the temperature is raised, the vacuum pumping continues to react, the acid value is monitored, when the acid value is reduced to 70-110mgKOH/g, the heating is stopped immediately, and the hyperbranched polymer is obtained after pouring, cooling and crushing.
  4. 4. The preparation method of the degradable high-permeability polyester resin is characterized by comprising the steps of dispersing cellulose nanocrystals in N, N-dimethylformamide, performing ultrasonic treatment to obtain a suspension, adding L-lactide and stannous octoate, introducing nitrogen for replacement, heating for reaction, washing, drying and grinding after the reaction is finished to obtain the modified nanocellulose.
  5. 5. The method for preparing a degradable high-permeability polyester resin according to claim 1, wherein the supercritical carbon dioxide injection amount is 1.2-2.0 wt% of the high-permeability polyester matrix.
  6. 6. The method for preparing the degradable high-permeability polyester resin according to claim 1, wherein a chain extender is added in the preparation process of the polyester resin, the chain extender is added in two stages, the addition amount is 15% -30% of the total amount through a side feeding port I in the first stage, and the addition amount is 70% -85% of the total amount through a side feeding port II in the second stage.
  7. 7. A degradable high-permeability polyester resin is characterized in that the degradable high-permeability polyester resin is prepared by the preparation method of any one of claims 1-6, and the raw materials for preparing the degradable high-permeability polyester resin comprise a high-permeability polyester matrix, an anti-hydrolysis agent, a hyperbranched polymer and modified nanocellulose.

Description

Degradable high-permeability polyester resin and preparation method thereof Technical Field The invention relates to the technical field of degradable polyester, in particular to degradable high-permeability polyester resin and a preparation method thereof. Background With the increasing importance of global white pollution, research and application of biodegradable polymer materials have become a hotspot in the field of material science. Among the numerous degradable materials, polybutylene succinate and polybutylene adipate/terephthalate are favored for their excellent processability and mechanical properties. However, the semi-crystalline polyesters face a significant difficulty in practical application, namely, the light transmittance and the mechanical properties are difficult to combine. Polybutylene succinate and polybutylene adipate/terephthalate have extremely high crystallization rates and high crystallinity. While high crystallinity imparts higher strength and modulus to the material, the resulting spherulites tend to be larger in size than visible wavelengths, causing scattering of light, giving the material an opaque milky or waxy appearance. This greatly limits its application in the fields of high-end transparent packaging, agricultural greenhouse films, transparent sheets, and the like. In order to improve transparency, the prior art generally adopts two paths, namely, firstly, a random structure is introduced through copolymerization to destroy crystallization, but the melting point of the material is greatly reduced, the strength is weakened, the material becomes too soft and even sticky, and secondly, a nucleating agent is added to refine spherulites, but a conventional nucleating agent (such as talcum powder) is an opaque filler, and the addition amount is slightly large, so that new haze is introduced. In addition, the inorganic nano filler added for improving the mechanical property often causes agglomeration due to the difference of surface energy, so that the transparency is damaged, and stress concentration points are caused. Therefore, developing a degradable polyester resin capable of accurately regulating and controlling crystallization behavior, and realizing high light transmittance while maintaining and even improving mechanical strength is a technical problem to be solved currently. For this purpose, a degradable high-permeability polyester resin and a preparation method thereof are provided. Disclosure of Invention The invention aims to provide a degradable high-permeability polyester resin and a preparation method thereof. In order to achieve the above purpose, the present invention provides the following technical solutions: Unless otherwise specified, the parts in the invention are all parts by mass. The invention provides a preparation method of a degradable high-permeability polyester resin, which comprises the steps of uniformly mixing 100 parts of a high-permeability polyester matrix, 0.2 part of an anti-hydrolysis agent bis (2, 6-diisopropylphenyl) carbodiimide and 1-5 parts of a hyperbranched polymer in a high-speed mixer to obtain a high-permeability polyester composition, adding the high-permeability polyester composition into a main feeding port (a first zone) of a double-screw extruder with an aspect ratio of L/D=48:1, adding 1-3.5 parts of modified nanocellulose and a styrene-glycidyl acrylate copolymer type chain extender (Joncryl ADR-4368) through a side feeding port I (a fourth zone), injecting supercritical carbon dioxide in a sixth zone, adding the styrene-glycidyl acrylate copolymer type chain extender (Joncryl ADR-4368) in a side feeding port II (a ninth zone), performing vacuum devolatilization in an eleventh zone, cooling the extruded strip in a 45 ℃ water bath, performing 60 ℃ vacuum drying for 8 hours after granulating, and obtaining the polyester resin, wherein the temperature of the polyester resin is 220 ℃ below, the temperature is set to be 180 ℃ in the first zone and the eighth zone, and the eighth zone is set to be 180 ℃ in the first zone and the eighth zone. Preferably, the preparation method of the high-permeability polyester matrix comprises the steps of adding 118 parts of succinic acid, 90 parts of 1, 4-butanediol, 14.4 parts of 1, 4-cyclohexanedimethanol, 14.6 parts of isosorbide and 0.1 part of tetrabutyl titanate into a reaction kettle with a rectifying column, heating to 190 ℃, stirring at 150rpm for 3.5 hours, heating to 225-245 ℃, vacuumizing, reducing the pressure in 40 minutes to below 50Pa, adjusting the stirring at 80rpm, continuing to react for 3 hours, charging nitrogen, discharging, and water-cooling and granulating to obtain the high-permeability polyester matrix. Preferably, the hyperbranched polymer is prepared by adding 19.2 parts of anhydrous citric acid, 17 parts of isophorone diamine and 9 parts of 1, 4-butanediol into a reaction kettle with mechanical stirring and nitrogen protection, heating to 140 ℃, stirring at 200r