Polylactic acid foaming method

A technology of polylactic acid foaming and polylactic acid resin, which is applied in the field of polylactic acid foaming, can solve problems such as difficulty in obtaining high foaming ratio foaming materials, inability to wrap foaming agent to escape, and difficulty in foaming molding, etc., to achieve foaming Controllable magnification, uniform cell size, and high foaming magnification

Inactive Publication Date: 2020-03-27
佛山碧嘉高新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, because PLA is a crystalline material, its molecules have few long-chain branches and low melt strength, and the PLA melt is sensitive to temperature. As the temperature rises, the melt viscosity decreases a lot, which makes it impossible for the melt to wrap PLA when it is foamed. Bubbles prevent the escape of foaming agent, the foam film is unstable and easy to break, foam molding is difficult, and it is difficult to obtain a foaming material with high expansion ratio and uniform cells
[0005] Using supercritical carbon dioxide (CO 2 ) or nitrogen (N 2 ) as the foaming method of the foaming agent, often because the gas is released under the control of air pressure, it is easy to cause surface appearance defects; and equipment modification is required to increase gas generators, gas water pumping devices or flow adjustment devices, etc., equipment control is inconvenient, and the process complex and expensive to produce

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] First, urea is dissolved in water to prepare an aqueous solution with a mass concentration of 1%; then acrylic acid and azobisisobutylimidazole hydrochloride are mixed with the aqueous solution of urea according to a mass ratio of 1:0.05, and acrylic acid and azobisisobutylimidazole The dosage ratio of morphine hydrochloride and the above-mentioned urea aqueous solution is 1:50; mix and react at 50°C for 1 hour to obtain an initial reaction mixture, which is freeze-dried in a freeze-drying device and then pulverized into powder; Then, 100 parts by weight of polylactic acid resin and 5 parts by weight of the above-mentioned pulverized powder are mixed uniformly; the uniformly mixed material is added to the extruder, and the temperature of the extruder is set at 150 ° C and the screw speed is 80 Rotation / min, head pressure not less than 8Mpa, material not exceeding 2 / 3 volume of the hopper, melt extrusion, heat urea to expand during the extrusion process, making the polyla...

Embodiment 2

[0059] First, urea is dissolved in water to prepare an aqueous solution with a mass concentration of 10%; then acrylic acid and azobisisobutylimidazoline hydrochloride are mixed with the aqueous solution of urea in a mass ratio of 1:3, and acrylic acid and azobisisobutylimidazoline The dosage ratio of hydrochloride and the above-mentioned urea aqueous solution is 1:70; mix and react at 50°C for 2 hours to obtain the initial reaction mixture, which is freeze-dried in a freeze-drying device and then ground into powder; then Mix 100 parts by weight of polylactic acid resin and 15 parts by weight of the above-mentioned pulverized powder; add the uniformly mixed material into the extruder, set the temperature of the extruder to 180°C, and the screw speed to 90 rpm / min, the head pressure is not lower than 8Mpa, and the material does not exceed 2 / 3 of the volume of the hopper. Melt extrusion is carried out. During the extrusion process, the urea is heated to expand, so that the polyl...

Embodiment 3

[0061] First, urea is dissolved in water to prepare an aqueous solution with a mass concentration of 20%; then, acrylic acid and azobisisobutylimidazole hydrochloride are mixed with the aqueous solution of urea according to a mass ratio of 1:5, and acrylic acid and azobisisobutylimidazole The dosage ratio of morphine hydrochloride and the above-mentioned urea aqueous solution is 1:100; mix and react at 80°C for 1.5 hours to obtain the initial reaction mixture, which is freeze-dried in a freeze-drying device and then ground into powder ; Then the polylactic acid resin of 100 weight parts and the above-mentioned pulverized powder of 30 weight parts are mixed uniformly; The material mixed homogeneously is joined in the extruder, the temperature of setting extruder 200 ℃, screw speed are 110 rpm, head pressure not less than 8Mpa, material not exceeding 2 / 3 of the volume of the hopper, melt extrusion, heat urea to expand during the extrusion process, so that the polylactic acid melt...

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Abstract

The invention discloses a polylactic acid foaming method. The polylactic acid foaming method comprises the following steps that A, a gas-generating agent is dissolved into water to prepare a solution;B, monomer or oligomer, a thermal crosslinking agent are mixed with the aqueous solution of the step A to obtain an initial reaction mixed solution, and after the initial reaction mixed solution is frozen and dried in a freeze drying device, grinding is conducted; C, polylactic acid resin and the ground initial reaction mixture powder obtained in the step B are uniformly mixed; D, the uniformly mixed material in the step C is added into an extruder, process parameters of the extruder are set for melt extrusion, the gas-generating agent is heated and generated expansion during the extrusion process, and a polylactic acid melt displays a foaming state; and E, the polylactic acid melt in the step D is extruded through the extruder and the polylactic acid foaming material is obtained after cooling and shaping. The foaming method is simple and efficient, no special equipment is needed, the cost is low, the operation is easy, the control is easy, and the obtained foaming material is stablein quality, uniform in the foam size, and high in the foaming rate.

Description

technical field [0001] The invention relates to the technical field of polymer material processing, in particular to a polylactic acid foaming method. Background technique [0002] Polymer foam has properties such as low density, heat insulation, shock absorption and cushioning, and is widely used in fields such as cushioning and packaging. According to the different foaming agents used, the foaming process can be divided into chemical foaming and physical foaming. Microcellular foamed polymer refers to a polymer porous material with a cell size of 1-100 μm. Since the 1980s, microcellular foaming technology has been concerned by scientists all over the world. The microcellular foaming process usually uses supercritical carbon dioxide (CO 2 ) or nitrogen (N 2 ) as a blowing agent. [0003] Polylactic acid resin (PLA) is a biodegradable and renewable material. In addition, compared with other biodegradable polyester materials, PLA has many advantages such as good mechani...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C48/25B29C48/92C08L67/04C08J9/08C08J3/24
CPCB29C48/022B29C48/25B29C48/92B29C2948/92514B29C2948/92704C08J3/24C08J9/08C08J2203/02C08J2367/04
Inventor 吴永升朱锦汤兆宾刘斐张传芝马松琪李俊
Owner 佛山碧嘉高新材料科技有限公司
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