Polypropylene foam product with low molding pressure and its preparation method

A technology for forming pressure and foamed products, applied in the field of foamed products, can solve the problems of uneven cell structure of polypropylene foamed products, affecting the particle properties of polypropylene foamed products, surface adhesion and other problems, and achieve excellent mechanical properties, The effect of high cell uniformity and uniform cell structure

Active Publication Date: 2022-02-25
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, polypropylene foamed products with a melting point of 150°C usually require a molding pressure of 0.35 MPa or more, which exceeds the upper limit of the pressure resistance of existing molding machines. It is necessary to provide special high-pressure molding devices for them, which makes the cost higher
[0004] In addition, various additives in the preparation process will affect the particle properties of polypropylene foamed products, such as surface adhesion, cell collapse, etc., thus making the cell structure of polypropylene foamed products uneven

Method used

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  • Polypropylene foam product with low molding pressure and its preparation method
  • Polypropylene foam product with low molding pressure and its preparation method
  • Polypropylene foam product with low molding pressure and its preparation method

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preparation example Construction

[0035] In order to be able to use lower molding pressure to prepare polypropylene foam products with uniform cell structure and excellent mechanical properties, please refer to figure 1 , The invention provides a polypropylene foam product with low molding pressure and a preparation method thereof.

[0036] Specifically, the preparation method comprises the following steps:

[0037] Step S1: Mix the first resin, the second resin and the foaming aid, extrude and granulate to obtain blended beads, wherein the material of the first resin includes polypropylene resin, and the melting point of the first resin is 140°C to 165°C, and the melting point of the second resin is 15°C to 45°C lower than the melting point of the first resin;

[0038] Step S2: mixing the blended beads, dispersant, foaming agent, and dispersion medium, performing pressurized heat treatment at a first pressure and a first temperature, and then releasing the pressure to obtain foamed beads;

[0039] Step S3: ...

Embodiment approach 1

[0069] Extrusion granulation: 100 parts by weight of polypropylene resin with a melting point of 148°C, 60 parts by weight of LDPE resin with a melting point of 118°C and 5 parts by weight of foaming aid are placed in an extruder and mixed, Extruding, cooling, drawing, and pelletizing to form blended beads, the obtained blended beads have a diameter of 2 mm and an aspect ratio of 2:1.

[0070] Heat and pressure foaming: put the blended beads, dispersant and deionized water in a high-pressure reactor, and fill with 15 parts by weight of CO 2 , pressurized and heated to 2.3 MPa and 149° C., and released the pressure in an instant to release the pressure in the autoclave to atmospheric pressure to obtain foamed beads.

[0071] Loading pressure: place the foamed beads in a pressure tank after drying, fill with compressed air, pressurize under the second pressure and let it stand for a certain period of time to obtain prefabricated beads.

[0072] Molding: Put the pressure-loaded ...

Embodiment approach 2

[0075] This embodiment is basically the same as Embodiment 1, the only difference is:

[0076] Extrusion granulation: Add 100 parts by weight of polypropylene resin with a melting point of 150° C., 50 parts by weight of LDPE resin with a melting point of 118° C. and 10 parts by weight of foaming aid.

[0077] Heating and pressurizing foaming: put the blended beads, dispersant and deionized water in a high-pressure reactor, and fill with 10 parts by weight of CO 2 , pressurized and heated to 2.2MPa and 151°C.

[0078] Loading pressure: place the foamed beads in a pressure tank after drying, fill with compressed air, pressurize under the second pressure and let it stand for a certain period of time to obtain prefabricated beads.

[0079] Molding: Put the pressure-loaded prefabricated beads in a molding machine, and mold them by steam. The pressure of the steam is 0.23MPa, and the temperature of the steam is 120°C.

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Abstract

The invention relates to a low-molding-pressure polypropylene foam product and a preparation method thereof. The preparation method includes extrusion granulation, heating and pressurizing foaming, pressure loading, and molding. The low-molding foamed product obtained by the preparation method The pressure polypropylene foamed product has a uniform cell structure and excellent mechanical properties, and can effectively reduce the preparation cost. The tensile strength of the polypropylene foamed product with low molding pressure obtained in the present invention is greater than or equal to 0.75 MPa, and the density of the polypropylene foamed product with low molding pressure is less than or equal to 0.11 g / cm 3 , has a uniform cell structure and excellent mechanical properties, its foaming density is controllable, and its foaming ratio is high.

Description

technical field [0001] The invention relates to the technical field of foamed products, in particular to a polypropylene foamed product with low molding pressure and a preparation method thereof. Background technique [0002] Expanded Polypropylene (EPP) has certain mechanical properties, sound insulation properties, green and easy to degrade properties, so it has been widely used in the fields of automobiles, packaging, construction, sound insulation and heat insulation. [0003] Polypropylene foamed products with higher mechanical properties also have higher melting points, which require higher steam pressure during molding. For example, polypropylene foamed products with a melting point of 150°C usually require a molding pressure of more than 0.35 MPa, which exceeds the upper limit of the pressure resistance of existing molding machines. It is necessary to provide special high-pressure molding devices for them, which makes the cost higher. [0004] In addition, various a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L23/12C08L23/06C08L23/08C08L23/14C08L53/00C08L23/16C08K13/02C08K5/103C08K5/20C08K5/098C08K5/42C08K3/34C08K3/32C08J9/12C08J9/14B29C48/92B29C44/60B29C44/34B29B9/06
CPCC08J9/122C08J9/141C08J9/0061C08J9/0023C08J9/0028C08J9/0033C08J9/0066C08J9/0095C08J9/0071B29B9/06B29C48/92B29C44/3403B29C44/60C08J2323/12C08J2423/06C08J2423/08C08J2423/12C08J2203/06C08J2203/14C08J2423/14C08J2323/14C08J2353/00B29C2948/92704
Inventor 蓝小琴郑文革吴飞沈斌罗海斌崇云凯
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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