Method and material for preparing polylactic acid-natural rubber porous material by micropore injection molding foaming

Abstract

The invention belongs to the technical field of micropore injection molding foaming, and discloses a method and a material for preparing a polylactic acid-natural rubber porous material by micropore injection molding foaming. Grafts are prepared through emulsion polymerization; dried polylactic acid particles and glycidyl methacrylate-natural rubber grafts are mixed in proportion, and are molten and mixed by adopting a double-screw extruder for extrusion and granulation; the micropore injection molding foaming is performed on the mixed particles by adopting an injection molding machine with agas compression unit; and with a supercritical CO2 fluid as a foaming agent, a polylactic acid / natural rubber porous material is obtained. Polylactic acid is roughened and modified by adopting naturalrubber; and the method of grafting glycidyl methacrylate on the natural rubber is used for improving polarity of the natural rubber and compatibility with the polylactic acid. The foaming process issimple; the obtained foaming material is more uniform in bubble size and distribution; and meanwhile, the foaming material is better in toughness.

Description

technical field

[0001] The invention belongs to the technical field of microporous injection foaming, in particular to a method and material for preparing polylactic acid-natural rubber porous material by microporous injection foaming. Background technique

[0002] The development of microcellular injection foaming technology began in 1970 and 1980. The foaming process of microcellular injection molding is divided into three steps: nucleation, cell enlargement and cell stabilization. First, a supercritical fluid (usually nitrogen or carbon dioxide) is dissolved in the polymer melt as a blowing agent to form a polymer-gas homogeneous solution, that is, the polymer melt is supersaturated with gas. Then, the gas pressure suddenly drops below the saturation pressure, resulting in thermodynamic instability leading to the nucleation of cells. Cell growth is controlled by the diffusion rate of the gas and the strength of the polymer-gas melt. The cell density of microcellular in...

Examples

Embodiment 1

[0015] The dry polylactic acid pellets were mixed with the glycidyl methacrylate-natural rubber graft at a weight ratio of 95 / 5, and extruded and granulated by a twin-screw extruder. The extrusion temperature is 190° C., and the screw speed is 100 revolutions / min.

[0016] The blend pellets were subjected to microcellular injection foaming with supercritical CO 2 The fluid is a blowing agent. Injection temperature 200°C, mold temperature 50°C, injection speed 30cm 3 / s, supercritical CO 2 The fluid accounts for 1% of the mass of the polymer, and the polylactic acid / natural rubber porous material is obtained by injection molding.

Embodiment 2

[0018] The dry polylactic acid pellets and the glycidyl methacrylate-natural rubber graft were mixed in a weight ratio of 90 / 10, and extruded and granulated by a twin-screw extruder. The extrusion temperature is 180° C., and the screw speed is 90 revolutions / min.

[0019] The blend pellets were subjected to microcellular injection foaming with supercritical CO 2 The fluid is a blowing agent. Injection temperature 190°C, mold temperature 40°C, injection speed 30cm 3 / s, supercritical CO 2 The fluid accounts for 1% of the mass of the polymer, and the polylactic acid / natural rubber porous material is obtained by injection molding.

Embodiment 3

[0021] The dry polylactic acid pellets and the glycidyl methacrylate-natural rubber graft were mixed in a weight ratio of 85 / 15, and extruded and granulated by a twin-screw extruder. The extrusion temperature was 170° C., and the screw speed was 80 revolutions / min.

[0022] The blend pellets were subjected to microcellular injection foaming with supercritical CO 2 The fluid is a blowing agent. Injection temperature 180°C, mold temperature 20°C, injection speed 40cm 3 / s, supercritical CO 2 The fluid accounts for 0.5% of the mass of the polymer, and the polylactic acid / natural rubber porous material is obtained by injection molding.

technical field

[0001] The invention belongs to the technical field of microporous injection foaming, in particular to a method and material for preparing polylactic acid-natural rubber porous material by microporous injection foaming. Background technique

[0002] The development of microcellular injection foaming technology began in 1970 and 1980. The foaming process of microcellular injection molding is divided into three steps: nucleation, cell enlargement and cell stabilization. First, a supercritical fluid (usually nitrogen or carbon dioxide) is dissolved in the polymer melt as a blowing agent to form a polymer-gas homogeneous solution, that is, the polymer melt is supersaturated with gas. Then, the gas pressure suddenly drops below the saturation pressure, resulting in thermodynamic instability leading to the nucleation of cells. Cell growth is controlled by the diffusion rate of the gas and the strength of the polymer-gas melt. The cell density of microcellular in...

Examples

Embodiment 1

[0015] The dry polylactic acid pellets were mixed with the glycidyl methacrylate-natural rubber graft at a weight ratio of 95 / 5, and extruded and granulated by a twin-screw extruder. The extrusion temperature is 190° C., and the screw speed is 100 revolutions / min.

[0016] The blend pellets were subjected to microcellular injection foaming with supercritical CO 2 The fluid is a blowing agent. Injection temperature 200°C, mold temperature 50°C, injection speed 30cm 3 / s, supercritical CO 2 The fluid accounts for 1% of the mass of the polymer, and the polylactic acid / natural rubber porous material is obtained by injection molding.

Embodiment 2

[0018] The dry polylactic acid pellets and the glycidyl methacrylate-natural rubber graft were mixed in a weight ratio of 90 / 10, and extruded and granulated by a twin-screw extruder. The extrusion temperature is 180° C., and the screw speed is 90 revolutions / min.

[0019] The blend pellets were subjected to microcellular injection foaming with supercritical CO 2 The fluid is a blowing agent. Injection temperature 190°C, mold temperature 40°C, injection speed 30cm 3 / s, supercritical CO 2 The fluid accounts for 1% of the mass of the polymer, and the polylactic acid / natural rubber porous material is obtained by injection molding.

Embodiment 3

[0021] The dry polylactic acid pellets and the glycidyl methacrylate-natural rubber graft were mixed in a weight ratio of 85 / 15, and extruded and granulated by a twin-screw extruder. The extrusion temperature was 170° C., and the screw speed was 80 revolutions / min.

[0022] The blend pellets were subjected to microcellular injection foaming with supercritical CO 2 The fluid is a blowing agent. Injection temperature 180°C, mold temperature 20°C, injection speed 40cm 3 / s, supercritical CO 2 The fluid accounts for 0.5% of the mass of the polymer, and the polylactic acid / natural rubber porous material is obtained by injection molding.

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