Preparation method of polyester combination, polyester combination and application of polyester combination

Abstract

The invention discloses a preparation method of a polyester combination with low cyclic trimer content, and the polyester combination prepared through the preparation method. According to the preparation method, aromatic dicarboxylic or esterified derivatives of the aromatic dicarboxylic and aliphatic diol are subjected to a reaction, so that small molecular polymers are obtained, then the small molecular polymers are subjected to the polymerization reaction under the action of a catalyst and stabilizer phosphorus compounds, and finally the polyester combination is obtained through solid phase polymerization, specifically, the temperature of solid phase polymerization is 180-240 DEG C, and the vacuum degree is 200-9000 Pa. As for the obtained polyester combination, the intrinsic viscosity is 0.5-0.8 dl/g, the content of cyclic trimer in the polyester combination is 0.2-0.8 wt%, and the growth speed of cyclic trimer in the polyester combination is below 0.015 wt% at the fusion temperature of 300 DEG C in the nitrogen atmosphere. The polyester combination can be applied to products like films.

Description

technical field [0001] The present invention relates to a method for producing a polyester composition, the polyester composition produced by the method and the use of the polyester composition. Background technique [0002] Polyester, especially polyethylene terephthalate (PET), polytrimethylene terephthalate (PPT), polybutylene terephthalate (PBT), because of its excellent mechanical properties, chemical Characteristic, dimensional stability and transparency, widely used in fiber, film, resin and other fields. [0003] Generally, by-product oligomers are unavoidably produced during the polymerization of polyester, and their amount generally accounts for about 2wt% of the total amount of polyester. Said oligomers mainly refer to polymerized monomers, dimers, cyclic trimers, etc., among which cyclic trimers account for the vast majority, accounting for about 1 wt% of the total polyester. During the process of film making or spinning, oligomers will pollute some components ...

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Problems solved by technology

However, the polyester obtained by this method is easy to precipitate chelating agent, boron salt, etc. during the high-temperature processing in the later stage, and the regeneration inhibition effect on the specific oligomer cyclic trimer is not obvious

The second method is to reduce the content of the cyclic trimer in the polyester through solid-state polymerization or heat treatment under an inert gas, but this method can only reduce the content of the initial cyclic trimer in the polyester , cannot solve the problem of its regeneration in the subsequent high-temperature processing environment

There are also methods such as Chinese patent CN102421820A disclosing a kind of polytrimethylene terephthalate pellets with reduced oligomers. The preparation method is to use organic solvents to extract from polyester to remove cyclic trimers. This method Subsequent recovery of a large amount of organic solvents is required, the cost is high, the operation is troublesome, and it is difficult to implement in industry

There is also a method to reduce the regeneration rate of the cyclic trimer by changing the catalyst formulation and increasing the amount of the stabilizer phosphorus compound, but due to the increase in the amount of the phosphorus compound, the low deceleration rate of the cyclic trimer in the solid phase polymerization Reduced, the initial cyclic trimer of the polyester composition after solid-state polymerization is relatively high, even if few cyclic trimers are regenerated during the film-making process, oligomers still precipitate in the film

Although the amount of initial cyclic trimer can be reduced by prolonging the time of solid-phase polymerization, due to the long-term solid-phase polymerization, the intrinsic viscosity of the polyester composition after solid-phase polymerization is too high, and it is not easy to form a film

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