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CN-122011598-A - Flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer and preparation method thereof

CN122011598ACN 122011598 ACN122011598 ACN 122011598ACN-122011598-A

Abstract

The invention discloses a flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer and a preparation method thereof, which relate to the technical field of automotive interior materials, and the thermoplastic elastomer adopts a bio-based hyperbranched polymer containing multi-carboxyl and amino functional groups as a multifunctional modifier, combines with trace food-grade zinc oxide, forms a reversible dynamic coordination crosslinking network in the melt blending process, can enhance the compatibility and melt strength of PP and EPDM, the mechanical property of the material is improved, sulfur-containing, nitrogen-containing and oxygen-containing micromolecule VOCs generated in the anchoring processing process can be chelated through the coordination effect of zinc ions, meanwhile, the halogen-free flame retardant is introduced to realize the flame retardant function, and finally, the automobile interior material with excellent cooperation of the flame retardant property, the mechanical property and the low VOCs property is obtained, so that the material can be widely applied to automobile interior parts and has good application prospect.

Inventors

  • LI ZHICHENG
  • LIANG LIHUA
  • ZHANG CHUNYI

Assignees

  • 深圳市鑫鹏宇新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260306

Claims (9)

  1. 1. The flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer is characterized by comprising, by weight, 40-60 parts of PP resin, 20-35 parts of EPDM rubber, 3-8 parts of bio-based hyperbranched polymer, 0.1-1.0 part of food-grade zinc oxide, 10-25 parts of halogen-free flame retardant, 0.2-0.8 part of antioxidant and 0.3-0.9 part of lubricant; the bio-based hyperbranched polymer is a bio-based hyperbranched polymer containing multiple carboxyl and amino functional groups, the number average molecular weight of the bio-based hyperbranched polymer is 5000-20000, the carboxyl content is 2.5-5.0mmol/g, the amino content is 1.0-2.5mmol/g, and the bio-based hyperbranched polymer is prepared by amidation and polymerization reaction of amino-terminated aliphatic bio-based compounds and carboxylic acid or anhydride containing unsaturated double bonds; The grain diameter of the food-grade zinc oxide is 20-50nm, and the purity is more than or equal to 99.5%; the halogen-free flame retardant is one or a mixture of more than two of magnesium hydroxide, aluminum hydroxide and phosphorus flame retardants, wherein the phosphorus flame retardant is phosphate or ammonium polyphosphate flame retardant.
  2. 2. The flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer according to claim 1, wherein the PP resin is homo-PP or co-PP, the melt index is 10-30g/10min, the Mooney viscosity of the EPDM rubber is 40-80, the ethylene content is 45% -65%, and the third monomer content is 3% -8%.
  3. 3. The flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer is characterized in that the antioxidant is a compound system of hindered phenol antioxidants and phosphite antioxidants, the compound mass ratio is 1:1-2, and the lubricant is one or a mixture of more than two of stearic acid, butyl stearate and polyethylene wax.
  4. 4. The flame retardant low VOCs automotive interior PP/EPDM thermoplastic elastomer of claim 1, wherein the method for preparing the bio-based hyperbranched polymer comprises the steps of: Taking an amino-terminated aliphatic bio-based compound and an unsaturated double bond compound containing anhydride and carboxylic acid as raw materials, taking toluene as a solvent, heating and refluxing for 2-5 hours at 65-110 ℃, cooling and separating to obtain an amide compound containing unsaturated double bonds; Mixing the obtained amide compound containing unsaturated double bond with carboxylic acid monomer containing double bond, adding initiator and molecular weight regulator into deionized water as solvent, reacting for 3-5h at 40-95 ℃, and spin-evaporating to obtain the multi-carboxyl and multi-amino bio-based hyperbranched polymer.
  5. 5. The flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer according to claim 4, wherein the molar ratio of the amino-terminated aliphatic bio-based compound to the unsaturated double bond compound containing anhydride and carboxylic acid is 1:2.0-4.0, the mass ratio of the unsaturated double bond-containing amide compound to the double bond-containing carboxylic acid monomer is (20-40): 40-60%, the initiator accounts for 5-10% of the mass of the double bond-containing carboxylic acid monomer, and the molecular weight regulator accounts for 2-6% of the mass of the double bond-containing carboxylic acid monomer.
  6. 6. The flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer according to claim 4, wherein the unsaturated double bond compound containing acid anhydride and carboxylic acid is one or a mixture of more of maleic acid, itaconic acid, maleic anhydride and itaconic anhydride, the carboxylic acid monomer containing double bonds is one or a mixture of more of acrylic acid, methacrylic acid and maleic acid, the initiator is one of ammonium persulfate and potassium persulfate or a mixture of sodium bisulphite, and the molecular weight regulator is one or a mixture of isopropanol and dodecyl mercaptan.
  7. 7. A method for preparing the flame retardant low VOCs automotive interior PP/EPDM thermoplastic elastomer as claimed in any one of claims 1 to 4, comprising the following specific steps: The preparation method comprises the steps of raw material pretreatment, namely respectively placing PP resin and EPDM rubber into a forced air drying oven, drying for 2-4h at 80-100 ℃, stirring once every 1h in the drying process to ensure uniform removal of moisture, and cooling to room temperature for standby after drying; The method comprises the steps of (1) selecting a double-screw extruder with a screw length-diameter ratio of 36:1-40:1, preheating each section of the double-screw extruder to a set value for 20-30min to ensure the stability of each section of temperature, adding dried PP resin and EPDM rubber into a feed inlet of the double-screw extruder in proportion, adjusting the rotating speed of the screw to 300-500r/min, feeding at a feeding rate of 20-30kg/h, carrying out melt plasticization for 3-5min, adding a mixing auxiliary agent at a constant speed through a side feed inlet, continuing to carry out melt blending for 5-10min, controlling the pressure in a barrel of the extruder to be 10-15MPa, and forming a reversible dynamic coordination cross-linking network between zinc ions and carboxyl groups on a bio-based hyperbranched polymer and oxygen-containing groups on a PP/EPDM chain in the melt blending process; Extruding and granulating, namely extruding the melted and blended materials through a head of a double-screw extruder, cooling the extruded melt strips through a water cooling tank, conveying the cooled melt strips into a granulator, regulating the rotating speed of the granulator to be 200-300r/min and the granulating length to be 2-3mm to obtain flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer particles, putting the particles into a blast drying box, drying at 70-80 ℃ for 1-2h, removing surface moisture, screening to remove unqualified particles, and packaging for later use.
  8. 8. The method for preparing the flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer according to claim 1, wherein the temperatures of all the sections of the twin-screw extruder are 160-170 ℃, 170-180 ℃, 180-190 ℃ and 185-190 ℃ in sequence, and the temperature of the machine head is 180-185 ℃.
  9. 9. The method for preparing the flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer according to claim 1, wherein the cooling water temperature of the water cooling tank is 20-30 ℃ and the cooling time is 5-10s.

Description

Flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer and preparation method thereof Technical Field The invention relates to the technical field of automotive interior materials, in particular to a flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer and a preparation method thereof. Background With the rapid development of the automobile industry and the improvement of health consciousness of consumers, the performance requirements of the automobile interior material are increasingly stringent, in terms of environmental protection, volatile organic compounds released by the material in the processing and using processes, such as benzene, formaldehyde, ethylbenzene and the like, are required to be strictly controlled, and small molecular substances not only generate pungent smell but also harm human health, in terms of safety, the automobile interior material must meet the flame retardant requirements so as to cope with fire risks and ensure the life safety of passengers, meanwhile, the material also needs to have good comprehensive performance so as to ensure the normal use of the component and good melt strength so as to meet the processing and molding requirements, and the PP/EPDM thermoplastic elastomer has the rigidity and processability of PP and the elasticity and weather resistance of EPDM, and is widely applied to components such as automobile instrument panels, door panels, seats and ceilings. The existing PP/EPDM thermoplastic elastomer has two major core problems, namely poor compatibility of PP and EPDM, such as low mechanical properties of materials, such as low tensile strength and impact strength, poor melt strength, and further influences the processing and forming effects, so that the quality of the produced interior trim part is difficult to ensure, and secondly, in the processing and using processes, the materials release sulfur-containing, nitrogen-containing, oxygen-containing and other small-molecule VOCs, which cause adverse effects on the quality of air in a vehicle, and in order to solve the problems, a series of measures are adopted in the prior art, but the prior art has obvious defects, such as that a compatilizer is often adopted to improve the compatibility of PP and EPDM, however, the compatilizer has single function, only the compatibility can be improved, long-term control of the VOCs cannot be realized, and the adsorbent is adopted to adsorb the VOCs, but the adsorbent belongs to physical adsorption, has limited adsorption capacity and is easy to saturate, and can influence the mechanical properties and the processing properties of the materials, and in addition, the existing modifier is mostly petroleum-based products, does not accord with the development trend of green environmental protection, and the synergistic promotion of the mechanical enhancement, the VOCs control and the flame retardant property is difficult to realize. Disclosure of Invention The invention aims to make up the defects of the prior art and provides a flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer and a preparation method thereof, which can form a reversible dynamic coordination crosslinking network in the melt blending process by adopting a bio-based hyperbranched polymer containing multiple carboxyl and amino functional groups as a multifunctional modifier and combining with trace food-grade zinc oxide, the network can not only enhance the compatibility and melt strength of PP and EPDM, improve the mechanical property of the material, but also chelate small molecular VOCs containing sulfur, nitrogen and oxygen generated in the anchoring processing process by the coordination effect of zinc ions, simultaneously introduce a halogen-free flame retardant to realize a flame retardant function, finally obtain an automotive interior material with excellent synergistic flame retardant property, mechanical property and low VOCs property, and can be widely applied to automotive interior parts and has good application prospect. On the one hand, the flame-retardant low-VOCs automotive interior PP/EPDM thermoplastic elastomer comprises, by weight, 40-60 parts of PP resin, 20-35 parts of EPDM rubber, 3-8 parts of bio-based hyperbranched polymer, 0.1-1.0 parts of food-grade zinc oxide, 10-25 parts of halogen-free flame retardant, 0.2-0.8 part of antioxidant and 0.3-0.9 part of lubricant; the bio-based hyperbranched polymer is a bio-based hyperbranched polymer containing multiple carboxyl and amino functional groups, the number average molecular weight of the bio-based hyperbranched polymer is 5000-20000, the carboxyl content is 2.5-5.0mmol/g, the amino content is 1.0-2.5mmol/g, and the bio-based hyperbranched polymer is prepared by amidation and polymerization reaction of amino-terminated aliphatic bio-based compounds and carboxylic acid or anhydride containing unsaturated double bonds; The grain diameter of the food-grade zinc oxide