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Polylactic acid pipe material resistant to physical aging, its preparation method and application

A technology of physical aging and polylactic acid, applied in the field of polylactic acid pipes and polylactic acid materials, can solve problems such as brittleness, achieve high crystallinity and orientation, maintain stability, and facilitate large-scale production

Active Publication Date: 2022-02-11
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
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  • Description
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Problems solved by technology

[0005] Although the above known technologies can prepare polylactic acid straws, under the current technical conditions, polylactic acid straws are not strictly designed and controlled from the essence of physical aging resistance because of their preparation processes (melt extrusion, traction, cooling, cutting). , it is easy to cause physical aging in the storage and logistics stage (shelf life) to cause rapid brittleness; therefore, it is necessary to develop new physical aging-resistant polylactic acid tube materials and their preparation methods to meet the comprehensive performance proposed by various applications higher requirements

Method used

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  • Polylactic acid pipe material resistant to physical aging, its preparation method and application
  • Polylactic acid pipe material resistant to physical aging, its preparation method and application

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preparation example Construction

[0042] In some embodiments, the preparation method specifically includes:

[0043] (1) Provide dry polylactic acid or polylactic acid dry mixture;

[0044] (2) Melting and extruding the dried polylactic acid or polylactic acid dry mixture through screw extrusion equipment to obtain a polylactic acid melt, wherein the screw temperature is 150-270°C;

[0045] (3) Stretch the polylactic acid melt in the axial direction at the screw mouth, the stretching temperature is equal to or greater than the glass transition temperature but lower than the melting point, preferably 65-145°C, and the stretching ratio is 1- 6 times, and then rapidly quenched to room temperature at a quenching rate of 2-800° C. / second, and the quenching time is 0.1-59 seconds, and a polylactic acid tube in the form of a hollow tube is obtained.

[0046] Wherein, the polylactic acid dry mixture may contain one or more of the aforementioned additional components.

[0047] In some embodiments, the weight average ...

Embodiment 1

[0081] Take polylactic acid with a weight average molecular weight of 150,000 and a molar content of L optical isomer of 95% for hot air drying at a drying temperature of 95±2°C, a drying time of 8 hours, and a water content of 50ppm; The material is extruded through the screw extrusion equipment to obtain the polylactic acid melt, and the screw temperature is 190°C; the polylactic acid melt is directly stretched in the axial direction at the screw mouth, the stretching temperature is 95°C, and the stretching ratio is 3 times; immediately Enter the rapid cooling device to obtain polylactic acid pipes in the form of hollow tubes, the quenching rate is 15°C / s, and the quenching time is 5 seconds; the cooled polylactic acid pipes are further pulled and cut to make polylactic acid disposable pipes; then The polylactic acid tubing is placed at its glass transition temperature T g The following sterilized packaging and storage. After testing: the crystallinity of the polylactic aci...

Embodiment 2

[0083] Take polylactic acid with a weight average molecular weight of 300,000 and a molar content of L optical isomer of 95% for hot air drying at a drying temperature of 95±2°C, a drying time of 8 hours, and a water content of 45ppm; The material is extruded through a screw extrusion equipment to obtain a polylactic acid melt, and the screw temperature is 230°C; the polylactic acid melt is directly stretched in the axial direction at the screw mouth, the stretching temperature is 115°C, and the stretching ratio is 2 times; immediately Enter the rapid cooling device to obtain polylactic acid pipes in the form of hollow tubes, the quenching rate is 3°C / s, and the quenching time is 30 seconds; the cooled polylactic acid pipes are further drawn and cut to make polylactic acid disposable pipes; then The polylactic acid tubing is placed at its glass transition temperature T g The following sterilized packaging and storage. After testing: the crystallinity of the polylactic acid pi...

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Abstract

The invention discloses a polylactic acid pipe material resistant to physical aging, its preparation method and application. The polylactic acid pipe is hollow tubular, and the polylactic acid pipe contains 0wt% to 85wt% crystalline phase and 15wt% to 100wt% amorphous phase; the amorphous phase contains 5wt% to 75wt% metastable phase , the characteristic peak of the metastable phase in the infrared spectrum appears at 918cm ‑1 place. The polylactic acid pipe material of the present invention has the characteristics of resistance to physical aging, the change rate of yield strength and elongation at break before and after storage is small, and the degree of orientation is high. Or better than the strength of the existing polylactic acid pipes, but also has excellent physical aging resistance, can maintain the stability of size and performance in the storage and logistics stage, and its preparation process is conducive to large-scale production, and has broad application prospects.

Description

technical field [0001] The invention relates to a polylactic acid material, in particular to a physical aging-resistant polylactic acid pipe, its preparation method and application (disposable straws, medical catheters, etc.), and belongs to the technical field of hollow pipes. Background technique [0002] With the vigorous development of the global petroleum industry, a large number of petroleum-based polymers are made into pipes every year, which are used in fields such as industry, medical treatment and daily life. Among them, the application of disposable plastic straws and medical catheters, because of the convenience of "throwing away after use", greatly facilitates people's diet and life and improves the safety of medical and health care. However, the uncertainty of health and safety caused by the precipitation of petroleum-based resin itself and related additives, as well as the "white" pollution caused by the non-degradability of petroleum-based resins to the envir...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L67/04
CPCC08L67/04C08L2203/18C08L2205/025C08L2201/08
Inventor 黄威陈鹏
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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