Spun filament type low-melting-point polyester chip and preparation method thereof

Abstract

The invention discloses a spun filament type low-melting-point polyester chip and a preparation method thereof. The method comprises the steps that terephthalic acid, isophthalic acid, ethylene glycol, diethylene glycol, triethylene glycol and the like serve as raw materials, and modified copolyester is synthesized through step-by-step esterification and polycondensation. According to the invention, the processes of process innovation, catalyst compounding, step-by-step esterification of modified monomers and the like are implemented; accurate regulation and control of modified monomers in theproduct are achieved, the prepared product is excellent in key quality index, the glass-transition temperature is higher than 66 DEG C, the carboxyl-terminated content is smaller than or equal to 25mol/T, the polycondensation reaction period is smaller than or equal to 200 min/batch, spun filaments used downstream are high in comprehensive efficiency and excellent in overall use effect, and theuse requirements of high-grade special fields are met.

Description

technical field [0001] The invention relates to a preparation method of spinning filament type low-melting point polyester, which belongs to the field of differential polyester manufacturing. Background technique [0002] Ordinary PET polyester has a melting point of 250-260°C, and low-melting-point polyester has a melting point of 105-210°C. It changes the molecular structure of PET by copolymerizing modified monomers to achieve the effect of lowering the melting point. At present, the mainstream models with low melting point in the market are 110°C, 180°C and 210°C. Among them, 110°C products can be spun into filaments or short fibers and are mainly used in the field of thermal bonding of non-woven fabrics and 3D flying shoes, and 180°C products are mainly used in In the field of spinning sheath-core composite yarn, 210°C products are mainly used in the field of polyester masterbatch manufacturing. According to the formula △T=△H / △S, it is necessary to reduce the melting e...

AI Technical Summary

Problems solved by technology

On the whole, there are two main types of low-melting point polyester chip production in China. The first type is the modification system of isophthalic acid and long-chain diols, and the second type is the modification system of adipic acid and long-chain diols. The modified monomers of the two systems are used to reduce the regularity of the polymer chain segment, so as to achieve the purpose of lowering the melting point. In the actual production process, the formula will be adjusted according to the downstream use characteristics, but often some applications The guarantee of performance will lead to damage to other performances of the product and affect the overall efficiency of the product

[0003] Chinese patent CN111100278A "A Manufacturing Method for Low-melting Polyester Chips" discloses a continuous low-melting point polyester chip production process. The formula uses titanium-based and antimony-based composite catalysts to play part of the environmental protection effect. Due to the continuous The disadvantage of formula production is that the modified monomer diethylene glycol is added in the diesterification reactor. From the actual production point of view, the reaction rate constant of diethylene glycol, PTA and IPA is small, the residence time of the diesterization reaction process is short, and the material is in In the diesterization reaction kettle, the esterification rate is high, and it is more difficult for diethylene glycol to re-polymerize to the main chain, which will eventually cause diethylene glycol to exist in a free state in the product, which will seriously affect the strength of the filament when it is spun.

Chinese patent CN110938196A "a low-melting point polyester and its preparation method", using aromatic dibasic acid and 2-methyl-1,3-propanediol to reduce the melting point of the product, adding an infrared absorber to increase the heat absorption rate of the product after processing, adding The free radical scavenger improves the thermal stability of the product, but the product uses 2-methyl-1,3-propanediol, the polycondensation process is difficult to control, and the hot-melt adhesive fluidity is worse than that of diethylene glycol or triethylene glycol

The increase of the glass transition temperature is conducive to the improvement of spinning efficiency, but when used in the hot-melt bonding process, the hot-melt rate will be affected, especially the 3D uppers made will be stiff and poor in wearing comfort

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