Full bio-based polylactic acid foaming material and preparation method thereof

A polylactic acid foaming, all-biological technology, applied in the field of polymer material processing and microcellular foaming, can solve the problems of poor performance uniformity and mechanical properties of blends, difficult recycling and dispersing of polylactic acid, etc. Improve melt strength and crystallization performance, improve melt performance and crystallization rate, and effect of uniform cell size

Inactive Publication Date: 2019-02-01
合肥华聚微科新材料有限责任公司
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  • Abstract
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  • Application Information

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Problems solved by technology

However, this technology uses chemical foaming agents for foaming, and at the same time adds additives such as chain extenders and plasticizers. The residue of small molecular substances will not only affect the mechanical properties of polylactic acid foaming materials, but also limit its application in food packaging.
CN201210032907 discloses a kind of polylactic acid degradable foaming and preparation method thereof, this technology adopts traditional chemical foaming agent, utilizes cross-linking agent to improve the melt strength of polylactic acid simultaneously, but after the chemical foaming agent decomposes, the inorganic substance Residues will affect the application range of polylactic acid foam materials, and the addition of cross-linking agents makes polylactic acid cross-linking difficult to recycle, which damages the original intention of using it as a biodegradable material
[0005] The second is to add anoth...

Method used

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  • Full bio-based polylactic acid foaming material and preparation method thereof
  • Full bio-based polylactic acid foaming material and preparation method thereof
  • Full bio-based polylactic acid foaming material and preparation method thereof

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preparation example Construction

[0038] A preparation method of full bio-based polylactic acid foam material, the steps are as follows:

[0039] (1) First dry the L-polylactic acid and the D-polylactic acid at 60-80°C for 6-8 hours, and then mix the dried L-lactic acid and the D-polylactic acid at a mass ratio of 90-99:10-1, Finally, the mixture is added to a twin-screw extruder for melt blending and drying to obtain polylactic acid containing stereocomplex crystals; the screw temperature of the twin-screw extruder is 140-180°C, and the screw speed is 50-150rpm; the melting zone temperature 140-200°C;

[0040] (2) Put the polylactic acid into an extrusion foaming machine at 140-200°C to melt it, then feed the foaming agent gas into the screw from the gas injection port metering pump on the extrusion foaming machine, and mix it with the polylactic acid melt Uniform, forming a single-phase polymer / gas melt;

[0041] (3) Reduce the temperature of the screw from the gas injection port to the machine head, so th...

Embodiment 1

[0046] (1) Blend the dried L-polylactic acid and D-polylactic acid at a mass ratio of 99:1, wherein the weight average molecular weight of the two is 15, and the corresponding isomer content is 1%. The screw extruder melts and blends, the screw temperature is 140-180° C., and the screw rotation speed is 50 rpm to obtain polylactic acid containing stereocomplex crystals.

[0047] (2) Put the dried polylactic acid containing stereocomplex crystals into an extrusion foaming machine to melt at a temperature of 140-200°C. At the same time, supercritical nitrogen accounting for 0.5% of the mass of polylactic acid is fed into the screw by a metering pump at the gas injection port on the extruder, and mixed evenly with the polymer melt to form a single-phase polymer / gas solution.

[0048] (3) Reduce the temperature of the screw from the gas injection port to the machine head, so that the melt temperature at the machine head is 110°C, and the pressure at the machine head is 8MPa. Final...

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Abstract

The invention discloses a full bio-based polylactic acid foaming material and a preparation method thereof. The method comprises the following steps: mixing dried L-polylactic acid and D-polylactic acid, and then adding a mixture to a twin-screw extruder and subjected to melt blending to obtain a polylactic acid containing a stereocomplex crystal; placing the material into an extrusion foaming machine to melt the material, then inputting a gas foaming agent into a screw through a gas injection port metering pump on the extrusion foaming machine, and uniformly mixing the material with a polylactic acid melt; reducing the temperature from a gas injection port to the screw at a head so that the temperature of the melt at the head is 110-140 DEG C and the pressure at the head is 6-8MPa, and finally performing extrusion foaming through a die, and performing cooling and fixing to obtain the polylactic acid foaming material. The method adopts L-polylactic acid and D-polylactic acid as raw materials, and forms the polylactic acid containing a stereocomplex crystal in the process of melt blending, which can significantly improve the melt strength and crystallization property of the polylactic acid. Therefore, the obtained polylactic acid foaming material has stable quality, uniform foam size, high foam density, and high foaming expansion ratio.

Description

technical field [0001] The invention belongs to the technical field of polymer material processing and microcellular foaming, and in particular relates to an all-bio-based polylactic acid foaming material and a preparation method thereof. Background technique [0002] Foamed plastic is a polymer-based microporous material containing a large amount of gas inside, which can be regarded as a special polymer / gas composite material. Due to the presence of the gas phase, foamed plastics combine the performance characteristics of both gas and polymer. Compared with unfoamed materials, foamed plastics have the characteristics of light weight, high specific strength, high impact strength, sound insulation, heat insulation and strong absorption capacity. They are used in packaging, automobiles, transportation, daily necessities, sports equipment and construction industries. have wide applications. However, the foaming materials widely used in industrial production are mainly soft an...

Claims

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Application Information

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IPC IPC(8): C08L67/04C08J9/12
CPCC08J9/122C08J2203/06C08J2203/08C08J2205/044C08J2367/04C08J2467/04
Inventor 汪龙汪彪
Owner 合肥华聚微科新材料有限责任公司
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