Search

CN-121975080-A - High-flow high-impact modified polypropylene composition and preparation method thereof

CN121975080ACN 121975080 ACN121975080 ACN 121975080ACN-121975080-A

Abstract

The application belongs to the technical field of polypropylene modification, and particularly relates to polyurethane, a preparation method and application thereof, a high-flow high-impact modified polypropylene composition, a polypropylene composite material and a preparation method thereof. According to the application, polyurethane with a special structure is designed and synthesized, and the cyclic tetrasiloxane with primary amino or secondary amino is used for blocking the polyurethane, so that a clearer microscopic phase separation structure is formed between the polyurethane and the polypropylene matrix. In the processing mixing shear, the polyurethane phase dispersed in the polypropylene matrix by means of the compatibilizer maleic anhydride grafted POE can deform and roll, and the overall flow resistance is reduced, so that the melt viscosity and the balance torque are reduced. On the other hand, by improving the microphase separation degree between the polyurethane and the polypropylene matrix, the energy can be more effectively transferred and dissipated, the toughening effect is more excellent, the impact resistance is improved, and particularly the impact strength at low temperature is obviously improved.

Inventors

  • LI YONG
  • SUN HONGLIANG
  • CAO XIWEI

Assignees

  • 思成新材料(大连)有限公司

Dates

Publication Date
20260505
Application Date
20260303

Claims (10)

  1. 1. A polyurethane is characterized by having the following structural general formula: the polyurethane is prepared by performing polycondensation reaction on diisocyanate and dihydric alcohol to obtain a prepolymer, and performing end-capping reaction on the prepolymer and mono-amino cyclotetrasiloxane; the structural general formula of the mono-amino cyclotetrasiloxane is as follows: ; Wherein R 1 and R 2 are the same or different and are each independently selected from alkyl groups of 1 to 4 carbon atoms or phenyl groups; R 3 is selected from alkyl, alkoxy or N-alkyl of 1 to 12 carbon atoms; r 4 is selected from a hydrogen atom or an alkyl, alkoxy or N-alkyl group of 1to 12 carbon atoms; R 3 and R 4 are connected or disconnected; The monoaminocyclotetrasiloxane contains 1 primary or secondary amino group; the structural general formula of the prepolymer is as follows: ; wherein n is selected from positive integers greater than or equal to 1; The diisocyanate is selected from aliphatic diisocyanates, and the corresponding R a is selected from straight-chain alkyl, branched-chain alkyl or cycloalkyl of 1 to 12 carbon atoms; The diol is selected from aliphatic diols, and the corresponding R b is selected from linear alkyl, linear alkoxy, branched alkyl, branched alkoxy, cycloalkyl or cycloalkoxy of 1 to 12 carbon atoms.
  2. 2. A process for producing the polyurethane according to claim 1, wherein a prepolymer is obtained by polycondensation of diisocyanate and diol in the presence of a catalyst, and the prepolymer is then subjected to a blocking reaction with monoaminocyclotetrasiloxane; Wherein the molar ratio of isocyanate groups of diisocyanate to hydroxyl groups of dihydric alcohol is 1.2-1.5; the molar ratio of the isocyanato groups of the prepolymer to the primary amino groups or the secondary amino groups of the monoamino cyclotetrasiloxane is (0.8-1.0): 1; the catalyst is selected from any one of organotin or organobismuth catalysts.
  3. 3. The preparation method according to claim 2, characterized in that the specific steps of the preparation method comprise: s1, mixing diisocyanate, dihydric alcohol and a catalyst for reaction to obtain an isocyanate group-terminated polyurethane prepolymer; S2, adding mono-amino cyclotetrasiloxane into the isocyanate group blocked polyurethane prepolymer prepared in the step S1 for continuous reaction to obtain cyclotetrasiloxane blocked polyurethane; wherein the reaction temperature in the step S1 is 60-100 ℃; the reaction temperature of the step S2 is 80-100 ℃.
  4. 4. Use of the polyurethane according to claim 1 in polypropylene composites.
  5. 5. A polypropylene composition comprising polypropylene, a compatibilizer, and the polyurethane of claim 1; The polypropylene is selected from polypropylene with melt flow index of 2.0-4.0 g/10 min (according to GB/T3682 standard); the mass percentage of the isotactic sequence in the polypropylene is more than 90 percent; the compatilizer is one or two selected from maleic anhydride grafted polymer and glycidyl methacrylate grafted polymer.
  6. 6. The polypropylene composition according to claim 5, wherein the polypropylene composition comprises an antioxidant; And/or, the polypropylene composition comprises a lubricant.
  7. 7. The polypropylene composition according to claim 6, wherein the antioxidant is selected from one or both of hindered phenol antioxidants and phosphite antioxidants; And/or the lubricant is one or more selected from stearic acid, metal soap salt of stearic acid, erucamide, oleamide, ethylene bis stearamide, polyethylene wax, fischer-Tropsch wax and polytetrafluoroethylene micropowder.
  8. 8. The polypropylene composition according to claim 5, wherein the polypropylene composition comprises 75 to 95 parts by mass of polypropylene, 5 to 15 parts by mass of a compatibilizer, and 10 to 30 parts by mass of the polyurethane according to claim 1.
  9. 9. A method for preparing a polypropylene composite material, comprising the steps of mixing the raw materials of the components of the polypropylene composition according to any one of claims 5-8, and then performing processing molding; The processing and forming steps comprise: s1, premixing all raw materials to obtain premix; s2, melting, blending and extruding the premix at 150-250 ℃; S3, cooling the melt blending extrusion product, granulating, and drying the granules for later use; s4, adding the dried particles into an injection molding machine, and performing injection molding to obtain the polypropylene composite material.
  10. 10. A polypropylene composite material prepared by the method of claim 9.

Description

High-flow high-impact modified polypropylene composition and preparation method thereof Technical Field The application belongs to the technical field of polypropylene modification, and particularly relates to polyurethane, a preparation method and application thereof, a high-flow high-impact modified polypropylene composition, a polypropylene composite material and a preparation method thereof. Background The polypropylene (PP) has the advantages of rich source, low price, easy molding and processing, excellent comprehensive performance of products and wide application in industries such as chemical industry, building, electric power, automobile, machinery, textile, medical treatment, packaging, building material furniture and the like. The homo-polypropylene is polymerized by a single propylene monomer, and the regularity of a molecular chain segment is very high (more than or equal to 95%), so that the homo-polypropylene has high crystallinity and poor impact resistance, and is more brittle at low temperature, and if the impact strength is improved by using a method for increasing relative molecular mass, the melt viscosity of the polypropylene can be obviously improved, and the molding processability is obviously deteriorated. Therefore, it is necessary to modify polypropylene to improve the impact resistance of polypropylene materials while maintaining mechanical properties and molding processability. As a modification method of polypropylene, there are methods such as copolymerization modification, blending modification and addition of a nucleating agent. For blending modification, elastomer materials such as polyurethane and the like are commonly used for blending with a polypropylene matrix, and hyperbranched polyurethane elastomer is designed and synthesized as a toughening agent of polypropylene in Chinese patent CN119661938B, and the disadvantage is that the polypropylene is strong in non-polarity, the polyurethane is a polar polymer, the compatibility of the polypropylene and the polyurethane is poor, the mechanical properties, particularly the elongation at break, are obviously influenced, the low-temperature impact resistance of the polypropylene is not improved enough, and the processability of the polypropylene composition is not improved. Disclosure of Invention Aiming at the defects of the prior art, the application designs the cyclotetrasiloxane terminated polyurethane with primary amino or secondary amino, the polyurethane, the compatilizer and the high isotacticity polypropylene form the high-flow high-impact modified polypropylene, and the impact toughness and the processing forming performance of the polypropylene at normal temperature and low temperature are improved on the premise of not sacrificing the tensile strength and the elongation at break. Wherein, the isosorbide-based polyurethane and the polypropylene modified by the isosorbide-based polyurethane have the best comprehensive performance, high mechanical property, high impact resistance and good processability. In order to achieve the technical purpose, the application adopts the following technical scheme: In a first aspect, a polyurethane has the structural formula: the polyurethane is prepared by performing polycondensation reaction on diisocyanate and dihydric alcohol to obtain a prepolymer, and performing end-capping reaction on the prepolymer and mono-amino cyclotetrasiloxane; the structural general formula of the mono-amino cyclotetrasiloxane is as follows: ; Wherein R 1 and R 2 are the same or different and are each independently selected from alkyl groups of 1 to 4 carbon atoms or phenyl groups; R 3 is selected from alkyl, alkoxy or N-alkyl of 1 to 12 carbon atoms; r 4 is selected from a hydrogen atom or an alkyl, alkoxy or N-alkyl group of 1to 12 carbon atoms; R 3 and R 4 are connected or disconnected; Preferably, a linkage between R 3 and R 4; The monoaminocyclotetrasiloxane contains 1 primary or secondary amino group; preferably, the mono-amino cyclotetrasiloxane comprises a piperazinyl group. The structural general formula of the prepolymer is as follows:; wherein n is selected from positive integers greater than or equal to 1; The diisocyanate is selected from aliphatic diisocyanates, and the corresponding R a is selected from straight-chain alkyl, branched-chain alkyl or cycloalkyl of 1 to 12 carbon atoms; preferably, the diisocyanate cycloaliphatic diisocyanate, the corresponding R a is selected from cycloalkanes of 1 to 12 carbon atoms; still preferably, the diisocyanate is selected from one or both of IPDI and HMDI; The diol is selected from aliphatic diols, and the corresponding R b is selected from linear alkyl, linear alkoxy, branched alkyl, branched alkoxy, cycloalkyl or cycloalkoxy of 1 to 12 carbon atoms; preferably, the diol is selected from cycloaliphatic diols containing at least 1 cycloalkyl or cycloalkoxy group per molecule; Preferably, the dihydric alcohol is selected from one or more of 1, 4-b