Method for synthesizing modified polyester

A modified polyester and esterification technology, applied in the field of polyester synthesis, can solve the problems of reduced product transparency, UV leakage, poor durability, etc.

Inactive Publication Date: 2008-04-30
CHINA RESOURCES PACKAGING MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The organic UV absorbers in Method 1 generally have certain toxicity, are not suitable for direct contact with food, have poor durability, lack of thermal stability, and complex processing procedures
Method 2 Particle dispersion is difficult, product transparency is reduced, and ultraviolet rays leak

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0021] A kind of preparation method of modified polyester, this preparation method comprises the following steps:

[0022] 1. First mix the dibasic acid and the dibasic alcohol in a molar ratio of 1:1 to 1.6, and at the same time add 2,6-naphthalene dicarboxylic acid chloride or 2,6-dihydroxynaphthalene, the addition amount is the weight of the dibasic acid 0.1% to 10%. At the same time, toner can be added for coloring, and the amount can be determined according to the color of the desired product slices. The catalyst and the phosphorus heat stabilizer can be added at this time, or can be added after the end of the esterification reaction and before the start of the polycondensation reaction. The slurry preparation process should be short in order to prevent denaturation of the reactive monomers. The esterification reaction conditions are: temperature 210-280° C., absolute pressure 0-1 MPa, and reaction time 0.5-6 hours.

[0023] 2. After the esterification reaction is finis...

Embodiment 1

[0026] 1. Mix terephthalic acid and ethylene glycol in a molar ratio of 1:1.3, and add 2,6-naphthalene dicarboxylic acid chloride in an amount of 0.5% of the weight of terephthalic acid. Add toner (blueness agent 0.6ppm, redness agent 0.5ppm, the above addition amount is based on the content in polyester). Antimony acetate was added in an amount of 600 ppm based on the total weight of the polyester. The preparation is uniform, and the esterification reaction is carried out; the esterification reaction temperature is 250-270°C, the reaction pressure is 0.3Mpa, and the reaction time is 2.5 hours;

[0027] 2. After the esterification is finished, add phosphoric acid as a heat stabilizer in an amount of 40ppm based on the weight of the polyester. The reaction pressure is slowly reduced to 50-1KPa, and the reaction temperature is 260-275°C for pre-condensation;

[0028] 3. After the pre-condensation, the reaction pressure is lowered to <50Pa, and the temperature is 270-285°C to c...

Embodiment 2

[0032] 1. Mix terephthalic acid and ethylene glycol in a molar ratio of 1:1.3, and add 2,6-dihydroxynaphthalene in an amount of 0.5% by weight of terephthalic acid. Add toner (blueness agent 0.6ppm, redness agent 0.5ppm, the above addition amount is based on the content in polyester). Antimony acetate was added in an amount of 600 ppm based on the total weight of the polyester. The preparation is uniform, and the esterification reaction is carried out; the esterification reaction temperature is 250-270°C, the reaction pressure is 0.3Mpa, and the reaction time is 2.5 hours;

[0033] 2. After the esterification is finished, add phosphoric acid as a heat stabilizer in an amount of 40ppm based on the weight of the polyester. The reaction pressure is slowly reduced to 50-1KPa, and the reaction temperature is 260-275°C for pre-condensation;

[0034] 3. After the pre-condensation, the reaction pressure is lowered to <50Pa, and the temperature is 270-285°C to carry out the final pol...

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PUM

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Abstract

The invention relates to a preparation method for modified polyester, and comprises the following steps: dibasic acid and dibasic alcohol are prepared into sizing material according to the mol ratio of 1:1.6 to 1, the sizing material is added into a reaction vessel after being stirred uniformly to perform the esterification reaction, and low molecular polymer is obtained through the reaction; the esterification reaction performs the polycondensation reaction, polymer melts are obtained, and through cooling, pelleting, and drying, polyester pellets are obtained; 2,6-naphthalenedicarboxylic acyl chloride or 2,6-dihydroxynaphthalene is added in the stage of the esterification reaction, the monomer participates in the whole reaction process, partial monomer units are directly coupled in the macromolecular chain segment, and catalyst, phosphorus heat stabilizer, and toner are added in the esterification or polycondensation stage. The polyester prepared through the invention can obstruct ultraviolet light with the wavelength below 360 nm, the polyester product is non toxic, the chemical stability is good, the manufactured product transparence is excellent, the ultraviolet leakage does not exist, and the final processing is convenient. A polyester bottle produced with the modified polyester pellets prepared by the invention has obstructing effect to the ultraviolet.

Description

technical field [0001] The invention relates to a preparation method of modified polyester, which belongs to the technical field of polyester synthesis. Background technique [0002] Polyester (PET) is a semi-crystalline thermoplastic material obtained by the reaction of terephthalic acid (PTA) and ethylene glycol (EG). Since its product came out, it has been favored by people because of its many excellent characteristics. In recent years, polyester has been widely used as a packaging material. Taking polyester bottles as an example, because the bottles made of this polymer have the advantages of light weight, not easy to break, good smell preservation, good transparency, etc., they have been widely used to package fruit juice, tea, edible oil, medicine, cosmetics, etc. items etc. However, vitamins, pigments and other substances in these items are more sensitive to ultraviolet rays, while ordinary polyester bottles do not have the function of blocking ultraviolet rays abo...

Claims

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Application Information

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IPC IPC(8): C08G63/64C08G63/78
Inventor 朱振达安泽坤宗建平文兰傅伟铮陈旭徐梅陈小雷
Owner CHINA RESOURCES PACKAGING MATERIALS CO LTD
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