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CN-122011596-A - Degradable polypropylene foaming material and preparation method thereof

CN122011596ACN 122011596 ACN122011596 ACN 122011596ACN-122011596-A

Abstract

The invention discloses a degradable polypropylene foaming material which is provided with a skin-core structure, wherein the skin-core structure comprises a core layer and a skin layer, the skin layer is coated outside the core layer, the weight ratio of the skin layer to the core layer is 1:4-4:1, the skin layer comprises the following raw materials of polypropylene resin, biodegradable polymer, degradation auxiliary agent, compatilizer and other auxiliary agents, and the core layer comprises the following raw materials of polypropylene resin, compatilizer, cellulose, degradation auxiliary agent and other auxiliary agents. The polypropylene foam material has the advantages that the skin-core structure particles are formed by adopting coextrusion, the skin layer is introduced with the combination of the biodegradation polymer and the degradation promoter, and the degradation promoter and the biodegradation polymer are subjected to synergistic degradation, the core layer retains a high-strength polypropylene and cellulose reinforcing system, so that the synergistic optimization of the mechanical property, the foaming property and the controllable degradability of the polypropylene foam material is realized, and the stability of the mechanical property in the using stage and the rapid degradation after discarding are ensured. The degradation rate of the material in 45 days under natural environment reaches more than 60%, and the degradation rate is controllable.

Inventors

  • GUO LIANGDONG
  • ZHANG XINGXING
  • YU BO
  • FENG LIUHAI
  • LIU GUOGANG
  • ZHENG ZHIGANG
  • WANG GENG
  • LIU HONGWEI
  • YU PEIQIAN
  • LI ZHIGUANG
  • WANG TAO
  • REN DONGXUE
  • ZHAO FEI
  • LI YAJUN

Assignees

  • 国能包头煤化工有限责任公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (10)

  1. 1. The degradable polypropylene foaming material is characterized by comprising a sheath-core structure, wherein the sheath-core structure comprises a core layer and a sheath layer, the sheath layer is coated outside the core layer, and the weight ratio of the sheath layer to the core layer is 1:4-4:1; the skin layer comprises the following raw materials, by weight, 60-80 parts of polypropylene resin, 10-30 parts of biodegradable polymer, 1-10 parts of degradation auxiliary agent, 1-3 parts of compatilizer and 0.3-3 parts of other auxiliary agents; The core layer comprises the following raw materials, by weight, 90-95 parts of polypropylene resin, 0.1-0.5 part of compatilizer, 1-5 parts of cellulose, 0.5-2 parts of degradation auxiliary agent and 0.3-3 parts of other auxiliary agents.
  2. 2. The degradable polypropylene foam material according to claim 1, wherein the polypropylene resin comprises binary copolymerized polypropylene and/or ternary copolymerized polypropylene, the polypropylene resin has a melting point of 130-160 ℃ and a melt index of 3.0-10.0g/10min.
  3. 3. The degradable polypropylene foam according to claim 1, wherein the biodegradable polymer comprises one or more of PLA, PBAT, PCL, PPC, PHA, PHB, PHBV, thermoplastic starch, starch-based modifier.
  4. 4. The degradable polypropylene foam according to claim 1, wherein the cellulose comprises one or more of natural cellulose fibers, microcrystalline cellulose, nanocellulose, nanocrystalline cellulose, modified cellulose derivatives.
  5. 5. The degradable polypropylene foam according to claim 1, wherein the compatibilizing agent comprises one or more of PP-g-MAH, POE-g-MAH, PE-g-MAH, PP-g-GMA, multifunctional epoxy oligomer.
  6. 6. The degradable polypropylene foam material according to claim 1, wherein the prodegradant comprises stearate.
  7. 7. The degradable polypropylene foam material according to claim 1, wherein the other auxiliary agents comprise antioxidants and nucleating agents.
  8. 8. A process according to claim 1 The method of the degradable polypropylene foaming material according to any one of the claims, which is characterized by comprising the following steps: S1, weighing a skin layer raw material and a core layer raw material, respectively and uniformly mixing the skin layer raw material and the core layer raw material, adding the uniformly mixed skin layer mixture and core layer mixture into extrusion equipment for coextrusion molding, and preparing the skin-core structure resin particles; S2, adding 70-90 parts by weight of sheath-core structural resin particles, 170-190 parts by weight of water, 0.1-0.5 part by weight of dispersing auxiliary agent and 0.1-0.2 part by weight of surfactant into a high-pressure foaming kettle, heating the kettle to 80-100 ℃ and stirring for 20-30min for pre-dispersing, then introducing a gas foaming agent, controlling the pressure rising rate to 0.1-0.3MPa/min to 2-5MPa of saturated pressure, heating to the saturated temperature of 130-160 ℃, keeping the temperature and the pressure constant for 30-120min under the condition, then releasing the pressure to normal pressure, cooling to normal temperature, taking out a product, washing with water, and drying to obtain the polypropylene primary foaming material with the foaming multiplying power of 10-20 times; Wherein, the dispersing auxiliary comprises kaolin, tricalcium phosphate and talcum powder; the surfactant comprises sodium dodecyl benzene sulfonate and sodium dodecyl sulfate. And S3, placing the polypropylene primary foaming material into a high-pressure tank, and introducing compressed air for pretreatment to obtain the degradable polypropylene foaming material with the foaming ratio of 20-45 times.
  9. 9. The method for preparing the degradable polypropylene foaming material according to claim 8, wherein in the step S1, the mass of the sheath-core structural resin particles is 0.5-1.5 mg/particle, the length-diameter ratio is 3/1-2/1, and the diameter is 0.5-1.0mm.
  10. 10. The method for preparing a degradable polypropylene foam according to claim 9, wherein the pretreatment in step S3 is performed under a pressure of 2.5-5bar for 16-24 hours, and then steam heating for 5-20 seconds.

Description

Degradable polypropylene foaming material and preparation method thereof Technical Field The invention belongs to the technical field of polypropylene foaming, and particularly relates to a degradable polypropylene foaming material and a preparation method thereof. Background The foaming material is widely applied to the fields of packaging, transportation, construction, automobiles, heat preservation, sound insulation, protection and the like due to the advantages of light weight, excellent buffering performance, low processing cost and the like. However, such materials typically only perform short-term functions, particularly disposable cushioning packaging materials and low value-added foam products, and are often discarded directly or simply landfilled after use is completed. Because the traditional foaming materials (such as polypropylene PP, polyethylene PE, polystyrene PS and the like) are fossil-based high polymer materials, the molecular chains are stable and are difficult to decompose by microorganisms, so that the traditional foaming materials exist in natural environments for a long time, and serious environmental pollution problems are caused, which are called white pollution. The wastes not only affect urban landscapes, but also accumulate in soil and water bodies, and cause potential threat to agricultural production, aquatic ecosystems and even biological chain safety. At present, the full-biodegradable foaming material (such as polylactic acid PLA, poly (adipic acid)/butylene terephthalate (PBAT), poly (butylene succinate) (PBS), poly (butylene succinate)/butylene terephthalate (PBST), polycaprolactone (PCL) and the like) can be decomposed into carbon dioxide, water and biomass by microorganisms under natural environment or composting conditions, and is a truly environment-friendly material. However, the application of the polyolefin foam material still has obvious bottlenecks, namely, the raw material cost is high, the processability is limited, and the mechanical properties are still different from those of the traditional polyolefin foam material. For example, PLA materials have strong rigidity and high transparency, but poor toughness, narrow foam window, and easy cracking, and PBAT has good flexibility, but high cost and low heat distortion temperature. Therefore, the full-biodegradable material is difficult to realize large-scale substitution in the fields of buffer packaging, building heat preservation and the like at the current stage. In contrast, polypropylene (PP) foam has excellent overall properties and cost advantages. The PP undergoes photo-oxidative degradation under the action of light, heat and oxygen in natural environment, i.e. the free radical reaction causes molecular chain cleavage, so that it gradually degrades into low molecular fragments after many years. However, this process is slow and complete biodegradation is difficult to achieve. In order to solve this technical problem, it is proposed to introduce biodegradable components into the polypropylene foam. For example, the prior patent (publication No. CN 102174209B), a preparation method of controllably degradable polypropylene foam particles, discloses a method for introducing a certain proportion of bioplastic into polypropylene resin by using a near-melting point foaming technology, and accelerating the environmental degradation speed of the polypropylene foam particles by the coordination effect of the environmental degradation of the bioplastic, and further realizing the purpose of controlling the environmental degradation speed of the polypropylene foam particles by controlling the mass percentage content of the bioplastic. As in the prior patent (publication No. CN113512253 a), a biodegradable foamed polypropylene and a preparation method thereof are disclosed, wherein calcium hydroxide and vinyl acetate are used for modifying starch, alkaline earth metal calcium hydroxide is used for primarily modifying starch to increase the compatibility of starch, and ceric ammonium nitrate is used for graft copolymerization of vinyl acetate and starch, so that the compatibility of modified starch after graft copolymerization is greatly increased, the mixing effect of starch and polypropylene is better, the biodegradation rate of polypropylene material is effectively improved, the photodegradation rate of polypropylene material can be effectively improved by adding photodegradation agent, and meanwhile, the foamed polypropylene material is treated by biodegradation and photodegradation, so that the degradation rate of the foamed polypropylene material is greatly improved. The preparation method has the technical problems that the preparation process is complex, the industrial production is not facilitated, the biodegradation rate is only 68% in 180 days and the photodegradation rate is only 70% in 180 days depending on the synergistic effect of the biodegradation and photodegradation of starch, and the degradation rat