Bottle grade polyester chip with low acetaldehyde content and preparation method thereof

Abstract

The invention relates to a bottle grade polyester chip with low acetaldehyde content, which is characterized in that in the bottle grade polyester chip, hydroxylated polydiene accounts for 0.1 to 5% of the total weight of the bottle grade polyester chip, polyanhydride chain extender accounts for 0.1 to 5% of the total weight of the bottle grade polyester chip, and transition metal carboxylate accounts for 0.005 to 0.5% of the total weight of the bottle grade polyester chip; under the action of the polyanhydride chain extender, the hydroxylated polydiene is polymerized on the main chain of the polyester; the intrinsic viscosity of the bottle grade polyester chip is 0.8 to 0.9dl/g. The invention also relates to a preparation method of the bottle grade polyester chip with low acetaldehyde content, and has the advantages that the generation amount of acetaldehyde is extremely low in the product processing process, with the content of acetaldehyde being less than 2ppm.

Description

1. Technical field [0001] The invention relates to a bottle-grade polyester chip, in particular to a bottle-grade polyester chip with a low acetaldehyde content used for packaging products that requires a high acetaldehyde content and a preparation method thereof. 2. Background technology [0002] Polyester is a general term for thermoplastic linear saturated polyester represented by polyethylene terephthalate (PET). One of its important uses is in the field of food packaging. As a food packaging material, PET can be made into biaxially stretched packaging film, and can also be made into amorphous preforms and then blown to obtain high-strength, high-transparency stretch blow-molded bottles, and can also be directly extruded into sheets The material is then thermoformed to produce a hollow container. PET products are transparent, oil-resistant, fragrant, hygienic and reliable, and have a wide range of operating temperatures, so their usage in the packaging field continues t...

AI Technical Summary

Problems solved by technology

[0003] The production of polyester for packaging includes liquid-phase polymerization and solid-phase polycondensation. The polyester chips produced in the liquid-phase polymerization process have acetaldehyde content as high as 50-100ppm. After solid-phase polycondensation, the polyester chips The content of acetaldehyde will be reduced to less than 1ppm; but in the process of using polyester to make packaging products, due to the need to use a screw extruder, the polyester in the extruder is subjected to high temperature heating and high shear of the screw, Polyester will undergo oxidative cracking and generate acetaldehyde, and the content of acetaldehyde in the final packaging product will rise to 5-10ppm again, and acetaldehyde is an irritating and volatile gas, which will be released during the use of packaging products. Gradually penetrate into the package contents, such as purified water, cola, beer and other beverages, thereby affecting their taste

[0004] Among the known ways to reduce acetaldehyde content, as disclosed in Chinese patent CN03131777.4, the acetaldehyde content in polyester chips can be reduced through formula adjustment and process optimization in the production process. This method can reduce the acetaldehyde content in the chips. acetaldehyde content, but does not reduce acetaldehyde formation during slice processing

[0005] Also, U.S. Patents US4,837,115, 5,340,884, etc. disclose that these patents reduce the acetaldehyde content in packaging products by adding polyamide substances during the slicing process, because the compatibility of polyamide and polyester is relatively poor, Decrease the transparency of the final product

[0006] Chinese patent CN01103833.0 and other patents reduce the content of acetaldehyde in products by adding acetaldehyde scavenger such as phosphoric acid, phosphoric acid ester and hindered amine antioxidant. Risk of migration into contents