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CN-121975212-A - Foamed polyolefin material and preparation method thereof

CN121975212ACN 121975212 ACN121975212 ACN 121975212ACN-121975212-A

Abstract

The invention discloses a foaming polyolefin material and a preparation method thereof, and belongs to the technical field of high polymer materials. The material consists of polyolefin resin, an elastomer, a composite foaming agent system, a cross-linking agent, an initiator and a lubricant. The composite foaming agent system is formed by respectively preprocessing a foaming agent, a nucleating agent and a foaming regulator, and then compounding the foaming agent after preprocessing, the foaming regulator after preprocessing and the nucleating agent after preprocessing according to the mass ratio of 1 (1.8-2) to 1.2-1.5. The preparation method comprises the steps of pretreatment, compounding and melt blending foaming of the components. The invention realizes the synergy of gas release, nucleation and melt strength increase through the pretreatment and synergistic proportioning of each component of the composite foaming system, effectively solves the problems of coarse and uneven cells and reduced mechanical properties of the traditional chemical foaming method, and the prepared material has the characteristics of fine and uniform cells, low density, excellent mechanical properties and stable process, and is suitable for a plurality of fields such as packaging, automobiles, buildings and the like.

Inventors

  • WANG HUIQIANG

Assignees

  • 陕西星元祺景科技有限公司

Dates

Publication Date
20260505
Application Date
20260228

Claims (7)

  1. 1. The foaming polyolefin material is characterized by comprising the following components in parts by mass: 60-90 parts of polyolefin resin; 5-20 parts of an elastomer; 5-15 parts of a composite foaming agent system; 0.5-3 parts of cross-linking agent; 0.1-1 part of initiator; 0.5-2 parts of lubricant; Wherein the polyolefin resin is at least one of polyethylene and polypropylene; The elastomer is at least one of ethylene-octene copolymer, styrene-butadiene-styrene block copolymer and ethylene-propylene copolymer; the cross-linking agent is at least one of trimethylolpropane trimethacrylate and divinylbenzene; the initiator is at least one of di-tert-butyl peroxide and dicumyl peroxide; The lubricant is at least one of zinc stearate and polyethylene wax; The composite foaming agent system consists of a foaming agent, a nucleating agent and a foaming regulator, wherein the nucleating agent is talcum powder or calcium carbonate, the foaming agent is azodicarbonamide or sodium bicarbonate, and the foaming regulator is zinc citrate.
  2. 2. The method for preparing a foamed polyolefin material according to claim 1, comprising the steps of: (1) The preparation method comprises the steps of (1) pre-treating a nucleating agent, namely placing the nucleating agent in an oven, heating to 60-70 ℃, preserving heat for 2-3 hours, then cooling to 25+/-2 ℃, adding the nucleating agent into an ethanol solution of a silane coupling agent, stirring for 1-2 hours, adding a dispersing auxiliary accounting for 2% -5% of the mass of the nucleating agent, continuously stirring for 10-15 minutes, and then drying for 1-3 hours under the vacuum condition at 60-80 ℃ to obtain the pretreated nucleating agent; (2) Uniformly dispersing a foaming agent into an aqueous solution of polyvinyl alcohol, heating to 50-60 ℃, stirring at a constant speed of 400rpm for 1-2 hours, then dropwise adding a mixed solution of methyl methacrylate monomer and potassium persulfate through a constant pressure dropping funnel at a speed of 10-20mL/min, wherein the dosage of the methyl methacrylate monomer is 10-20% of the mass of the foaming agent, the dosage of the potassium persulfate is 0.5-1.5% of the mass of the methyl methacrylate monomer, continuously stirring and reacting for 3-4 hours at 50-60 ℃ after the dropwise adding of the solution of the methyl methacrylate monomer and the potassium persulfate is completed, filtering the mixed solution, washing the obtained solid to be neutral by deionized water, and then drying in a vacuum drying box at 60-80 ℃ for 4-6 hours to obtain the pretreated foaming agent; (3) Pretreating a foaming regulator, namely placing the nano mesoporous silica and the foaming regulator into a high-speed mixer, mixing for 10-30 minutes at the rotating speed of 60-80 ℃ and 500-1500 rpm, adding paraffin, and mixing for 3-5 minutes at the temperature of 60-80 ℃ to obtain the pretreated foaming regulator; (4) According to the pretreated foaming agent and the pretreated foaming regulator, the mass ratio of the pretreated nucleating agent is 1 (1.8-2), the pretreated foaming agent in the step (2) is weighed (1.2-1.5), the pretreated foaming regulator in the step (3) is mixed with the pretreated nucleating agent in the step (1) for 10-15 minutes at the rotating speed of 200-300 r/min, and a composite foaming agent system is obtained; (5) Weighing 60-90 parts of polyolefin resin, 5-20 parts of elastomer, 5-15 parts of the composite foaming agent system prepared in the step (4), 0.5-3 parts of cross-linking agent, 0.1-1 part of initiator and 0.5-2 parts of lubricant according to parts by mass, adding the polyolefin resin and the elastomer into a double-screw extruder, carrying out melt blending for 10-20 minutes at 160-180 ℃ and a screw rotating speed of 200-250r/min to uniformly disperse the elastomer in a polyolefin matrix, sequentially adding the lubricant, the composite foaming agent system, the cross-linking agent and the initiator into the double-screw extruder, continuously melting for 0.5-1 hour at 160-180 ℃, extruding, and carrying out water cooling and granulating to obtain the foamed polyolefin.
  3. 3. The method for preparing a foamed polyolefin material according to claim 2, wherein the ethanol solution of the silane coupling agent in the step (1) is an ethanol solution with a mass concentration of 5% -8% of the silane coupling agent, and the amount of the silane coupling agent is 1.5% -3% of the mass of the nucleating agent.
  4. 4. The method of claim 2, wherein the dispersing aid in the step (1) is at least one of polyethylene wax, zinc stearate, and ethylene bis stearamide.
  5. 5. The method of claim 2, wherein the aqueous solution of polyvinyl alcohol in the step (2) is an aqueous solution with a polyvinyl alcohol mass concentration of 2% -5%, and the amount of polyvinyl alcohol is 2% -5% of the amount of the foaming agent.
  6. 6. The method of producing a foamed polyolefin material according to claim 2, wherein the mass ratio of the nano mesoporous silica in the step (3) to the foaming regulator is1 (2-3).
  7. 7. The method of claim 2, wherein the paraffin wax in the step (3) is added in an amount of 0.5% -1% of the total mass of the nano mesoporous silica and the foaming regulator.

Description

Foamed polyolefin material and preparation method thereof Technical Field The invention belongs to the technical field of high polymer materials, and particularly relates to a foaming polyolefin material and a preparation method thereof. Background Polyolefin materials are widely used in various fields because of their light weight, low cost, good chemical stability, easy processing, and the like. However, the conventional unfoamed polyolefin material has the disadvantages of high density, limited cushioning properties and the like. The micro-foaming technology can remarkably reduce the density of the material, improve the specific strength and impact toughness and endow the material with excellent heat insulation, sound insulation and buffering performance by introducing a large number of micro-sized (usually less than 100 mu m) cells which are uniformly distributed into the material. Therefore, the micro-foaming polyolefin material has wide application prospect in the fields of packaging, automobiles, buildings and the like. At present, the preparation methods of the micro-foaming polyolefin material comprise a physical foaming method and a chemical foaming method. The physical foaming method generally adopts inert gases such as carbon dioxide or nitrogen as a foaming agent, has the advantages of environmental friendliness, easy regulation and control of cell structures and the like, but has higher requirements on equipment, and the chemical foaming method generates gases through decomposition of the chemical foaming agent to foam, so that the process is simple, but the cell size and distribution are difficult to control. In addition, the micro-foaming material of the lower molecular weight resin system is difficult to combine mechanical property and foaming property, so that the application range of the micro-foaming material is limited. Therefore, the development of the foaming polyolefin material with excellent mechanical properties and fine cell structure has important significance. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a foaming polyolefin material and a preparation method thereof. The material is modified by blending polyolefin resin and elastomer, and chemical crosslinking is performed to increase the melt strength of the material, and the material is matched with a composite foaming agent system, so that the regulation and control of the cell structure and the cooperative promotion of the mechanical property are realized. In order to achieve the above purpose, the invention adopts the following technical scheme: A foaming polyolefin material consists of the following components in parts by mass: 60-90 parts of polyolefin resin; 5-20 parts of an elastomer; 5-15 parts of a composite foaming agent system; 0.5-3 parts of cross-linking agent; 0.1-1 part of initiator; 0.5-2 parts of lubricant. The polyolefin resin is at least one of polyethylene and polypropylene. The elastomer is at least one of ethylene-octene copolymer, styrene-butadiene-styrene block copolymer and ethylene-propylene copolymer. The cross-linking agent is at least one of trimethylolpropane trimethacrylate and divinylbenzene. The cross-linking agent can be subjected to cross-linking reaction with polyolefin molecular chains under the action of an initiator to form a three-dimensional network structure, so that the melt strength is remarkably improved, and a support is provided for the stability of cells. The initiator is at least one of di-tert-butyl peroxide and dicumyl peroxide. The initiator is decomposed to generate free radicals at the processing temperature to initiate the crosslinking reaction of the crosslinking agent and polyolefin molecular chains, and the decomposition temperature is matched with the decomposition temperature of the foaming agent to ensure that the crosslinking and the foaming are carried out cooperatively. The lubricant is at least one of zinc stearate and polyethylene wax. The lubricant can improve the dispersibility of each component in the melting process, reduce the melt viscosity, reduce the equipment wear, and simultaneously avoid the premature decomposition of the foaming agent caused by friction heat generation. The composite foaming agent system consists of a foaming agent, a nucleating agent and a foaming regulator, wherein the nucleating agent is talcum powder or calcium carbonate, the foaming agent is azodicarbonamide or sodium bicarbonate, and the foaming regulator is zinc citrate. A foamed polyolefin material, the method of preparation comprising the steps of: (1) The preparation method comprises the steps of (1) placing a nucleating agent in an oven, heating to 60-70 ℃, preserving heat for 2-3 hours, removing adsorbed water, cooling to room temperature of 25+/-2 ℃, adding the nucleating agent into an ethanol solution of a silane coupling agent, stirring for 1-2 hours, wherein the ethanol solution of the silane coupling agent is an eth