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CN-122011747-A - Internal demolding polyurethane composite material and preparation method and application thereof

CN122011747ACN 122011747 ACN122011747 ACN 122011747ACN-122011747-A

Abstract

The invention discloses an internal demolding polyurethane composite material, and a preparation method and application thereof, and belongs to the technical field of polyurethane materials. The composite material is formed by mixing and curing a first component (modified polyurethane containing side chain carboxyl and terminal double bonds) and a second component (cyclic polyurethane). The first component is prepared by ring-opening esterification of itaconic anhydride, the introduced side chain carboxyl effectively reconstructs a hydrogen bond network to enhance mechanical strength, the terminal double bond promotes the efficient migration of a demolding component to a mold interface, and the unique non-terminal topological structure of the second component effectively limits excessive sliding of a high molecular chain segment to permanently and stably anchor the demolding component at the interface. The invention effectively solves the problem that the traditional combined material is difficult to demold and the mechanical property is difficult to combine, realizes the excellent and durable internal demolding effect, greatly improves the tensile strength and toughness of the material, and is particularly suitable for preparing composite materials such as PHC cover plates of automobile trunk and the like.

Inventors

  • LIU CHANG
  • WANG HAIDAN
  • CHANG SHUANG

Assignees

  • 长春峰泰科技有限公司

Dates

Publication Date
20260512
Application Date
20260409

Claims (9)

  1. 1. A preparation method of an internal demolding polyurethane composite material is characterized by comprising the following steps of S1, preparing a first component, namely, taking 100 parts of macromolecular dihydric alcohol, 3.0-10.0 parts of first polyisocyanate, 0.1-1.5 parts of itaconic anhydride, 10.0-30.0 parts of second polyisocyanate, 2.0-8.0 parts of small molecular aliphatic dihydric alcohol chain extender, 0.01-0.05 part of organic metal catalyst as a raw material, carrying out single-end ring opening esterification by acid anhydride groups, S2, preparing a second component, namely, taking difunctional primary amine as an initiator A, initiating a macrocyclic monomer in a solvent to carry out ring opening polymerization reaction to obtain end amino telechelic polyurethane, carrying out amine-active ester coupling reaction with a p-nitrobenzene active esterifying agent compound B in the presence of triethylamine to obtain end azido telechelic polyurethane, dropwise adding the end azido telechelic polyurethane into a solution containing small molecular connecting agent sym-dibenzo-1, 5-cyclooctadiene-3, 7-diacetylene to obtain liquid cyclic polyurethane, and mixing the first component and the second component prepared in S3, and solidifying the second component.
  2. 2. The method for preparing the internal mold release polyurethane composite material according to claim 1, wherein in the step S1, the macromolecular diol is at least one selected from polycaprolactone diol, polycarbonate diol or polytetrahydrofuran diol, the number average molecular weight of the macromolecular diol is between 1000 and 3000g/mol, the chemical structures of the first polyisocyanate and the second polyisocyanate are the same or different, the first polyisocyanate and the second polyisocyanate are at least one selected from 4,4' -diphenylmethane diisocyanate, toluene diisocyanate or isophorone diisocyanate, the small-molecular aliphatic diol chain extender is at least one selected from 1, 4-butanediol, 1, 6-hexanediol or ethylene glycol, and the organometallic catalyst is dibutyl tin dilaurate or stannous octoate.
  3. 3. The preparation method of the internal mold release polyurethane composite material according to claim 1, which is characterized by comprising the following continuous operation steps of continuously stirring 100 parts of macromolecular dihydric alcohol for 1.5-3 hours at the temperature of 110-130 ℃ and under vacuum condition, reducing the system temperature to 50-70 ℃ under the protection of aprotic inert gas, adding 3.0-10.0 parts of first polyisocyanate, then heating to 75-85 ℃ for heat preservation reaction for 1.5-3 hours to prepare hydroxyl-terminated polyurethane prepolymer, adding 0.1-1.5 parts of itaconic anhydride into the prepolymer system, stirring at the constant temperature of 85-95 ℃ for 2.5-4 hours under the protection of aprotic inert gas, realizing end sealing on the main chain of the prepolymer, adjusting the system temperature to 75-85 ℃, sequentially adding 10.0-30.0 parts of second polyisocyanate and 2.0-8.0 parts of small molecular aliphatic dihydric alcohol chain extender, dropwise adding 0.01-0.05 parts of metal catalyst and 1-5.5% of methyl pyrrolidone as solid methyl pyrrolidone or the total reaction medium, wherein the total mass of the solid methyl pyrrolidone is 50-50% of the total reaction medium.
  4. 4. The method for preparing the internal mold release polyurethane composite material according to claim 1, wherein in the step S2, 40-60 parts by mass of macrocyclic monomer are dissolved in 300-350 parts by mass of N, N-dimethylformamide solvent, then 0.1-1 part by mass of initiator A is added, the mixed system is reacted for 1-2 hours at 85-95 ℃, then the quenching agent trifluoroacetic acid is added for quenching reaction, the reaction solution is precipitated twice in methanol, and a 0.22 mu m filter membrane is used for filtering and collecting the amine-terminated telechelic polyurethane, in the step S2, the purified and collected amine-terminated telechelic polyurethane is redissolved in 450-500 parts by mass of N, N-dimethylformamide, then 100-200 parts by mass of triethylamine and 100-130 parts by mass of compound B are added, and the amine-terminated telechelic polyurethane is obtained after reaction for 2-4 hours at room temperature.
  5. 5. The method for preparing an internal mold release polyurethane composition according to claim 1, wherein in the step S2, 30-50 parts by mass of the terminal azido telechelic polyurethane is dissolved in 18625 parts by mass of chloroform solvent to prepare a polymer solution, 10-30 parts by mass of sym-dibenzo-1, 5-cyclooctadiene-3, 7-diacetylene is dissolved in 55875 parts by mass of chloroform solvent to prepare a connecting agent solution, and the polymer solution is continuously and uniformly dripped into the connecting agent solution within 12 hours by a syringe pump, and then the ring-closure reaction is continued for 6-18 hours at room temperature to obtain the purified cyclic polyurethane.
  6. 6. The process for preparing an internal mold release polyurethane composition according to claim 1, wherein the initiator A in the step S2 is prepared by dissolving 4.5 to 8.5 parts by mass of hydroquinone in 113.3 parts by mass of N, N-dimethylformamide, adding 30 to 35 parts by mass of potassium carbonate, stirring at room temperature for 20 to 40 minutes, adding 35 to 40 parts by mass of N- (3-bromopropyl) phthalimide, reacting at 75 to 85 ℃ for 24 to 48 hours, filtering and collecting the filtrate with a 0.22 μm filter membrane, removing impurities by spin evaporation, dissolving the residue in chloroform, washing with a 2M aqueous sodium carbonate solution and deionized water in sequence to pH=7, purifying by silica gel column chromatography to obtain a compound I, dissolving 1 to 3 parts by mass of the compound I in 20 to 25 parts by mass of absolute ethyl alcohol, adding 0.2 to 0.6 part by mass of hydrazine hydrate, reacting at 75 to 85 ℃ for 1 to 3 hours, removing the solvent, dispersing the residue in water, adjusting pH to 4 with a 1M aqueous hydrochloric acid solution, filtering and collecting the filtrate with a 12,0.22 μm filter membrane, filtering and collecting the filtrate by filtering and filtering the aqueous solution.
  7. 7. The method for preparing an internal mold release polyurethane composition according to claim 1, wherein the preparation method of the p-nitrobenzene active esterifying agent in the step S2 comprises the steps of dissolving 10-30 parts by mass of 2, 6-diisopropylaniline in 150-200 parts by mass of acetonitrile, adding 0.2-0.8 part by mass of potassium iodide, and slowly dropwise adding 40-70 parts by mass of tert-butyl hydroperoxide within 60 minutes; stirring at room temperature for 30min, heating to 60-80 ℃ for 4-6h, adding saturated sodium thiosulfate aqueous solution for quenching, extracting with methylene chloride and purifying by column chromatography to obtain a compound II, dissolving 1-3 parts of the compound II in 30-50 parts of acetone, adding 1-4 parts of ammonium chloride, bubbling nitrogen for 30min, adding 1-3 parts of zinc powder, reacting at room temperature for 4-6h under nitrogen atmosphere, filtering with a 0.22 mu M filter membrane rapidly and concentrating the filtrate, extracting with methylene chloride to obtain an intermediate hydroxylamine derivative, dissolving the intermediate hydroxylamine derivative in 15-20 parts of diethyl ether, adding 25-35 parts of dilute sulfuric acid aqueous solution, stirring at room temperature for overnight, regulating pH to 8 with 2M sodium hydroxide solution, concentrating by diethyl ether extraction and stirring in n-pentane for 2-4h to obtain a white solid compound III, dissolving 1-2 parts of compound III in a mixed solution composed of 60-80 parts of glacial acetic acid and 6-10 parts of water, then adding 1-2 parts of sodium azide and 1-1.5 parts of sodium nitrite, reacting at 0 ℃ for 20-40min, extracting with ethyl acetate in a four-phase, drying by using a four-column chromatography to obtain a four-phase solvent, purifying by stirring at room temperature to obtain a four-phase compound 55, adding 1.5-2.5 parts of p-nitrophenyl chloroformate and 1-1.5 parts of triethylamine, stirring at room temperature for 20min, removing solvent by spin evaporation, and purifying by column chromatography to obtain the compound B, wherein the macrocyclic monomer in the step S2 is a stress relief type macrocyclic monomer with a main chain provided with a functional group or a sequence setting structural unit.
  8. 8. An internal mold release polyurethane composition, characterized in that the internal mold release polyurethane composition is obtained by the preparation method according to any one of claims 1 to 7.
  9. 9. An application of the internal mold release polyurethane composite material is characterized in that the internal mold release polyurethane composite material prepared by the preparation method of the internal mold release polyurethane composite material according to any one of claims 1-7 is added into automobile parts for application.

Description

Internal demolding polyurethane composite material and preparation method and application thereof Technical Field The invention belongs to the technical field of polyurethane materials, and particularly relates to an internal demolding polyurethane composite material, and a preparation method and application thereof. Background The PHC (Paper Honeycomb Core) cover plate is usually in a sandwich structure, and is formed by using honeycomb paperboard, corrugated paperboard or plastic plates and the like as core materials, upper and lower composite surface layers and surface decoration layers (such as fabrics, non-woven fabrics, PVC leather and the like). The PHC cover plate has the characteristics of impact resistance, corrosion resistance, sound insulation, heat insulation, high strength, good durability, high production efficiency and the like, and is widely applied to the fields of building, traffic, municipal engineering and the like, and particularly is widely applied to interior trim and storage parts such as automobile trunk cover plates, spare tire cover plates, storage plates and the like. In the process of preparing the automobile parts by using the glass fiber reinforced polyurethane composite material, polyurethane (PU) composite material plays a vital role as a framework and an adhesive. With the increase of the requirements for light weight and multifunction, the performance requirements for polyurethane composite materials are also higher and higher. The universal rigid foam polyurethane composite material applied to the PHC trunk cover plate in the early stage has the defects of large brittleness and unmatched thermal expansion coefficients. To improve these properties, polyether polyols are often compounded with polyester polyols and silane coupling agents are added to promote adhesion within the industry. However, in the continuous molding process of polyurethane composite materials, the demolding effect is another core element that determines the production efficiency, the appearance of the product, and the manufacturing cost. The traditional demolding mode is mostly dependent on frequent spraying of the external demolding agent on the surface of the mold, so that the production rhythm is seriously slowed down, and the surface of a product is extremely easy to be stained due to the residual external demolding agent, so that the subsequent coating or bonding process is influenced. The adoption of the internal demoulding process is an effective way for solving the problems. The mechanism of action of internal mold release agents is primarily dependent upon the migration of the release component to the article and mold interface and the formation of a barrier layer during polyurethane curing. However, the existing internal demolding polyurethane system has technical bottlenecks that on one hand, the addition of the conventional internal demolding agent tends to weaken the interaction among polyurethane molecular chains, so that the mechanical strength, flexibility and temperature resistance of the material are irreversibly reduced, and on the other hand, the curing speed and demolding performance are difficult to be compatible. In a fast curing system, the demolding component is not sufficiently migrated to the interface in the past, while in a conventional system, the migration rate of the internal demolding agent is difficult to accurately control due to the continuous motion of the linear polyurethane chain segments, the demolding durability is poor in continuous production, only a few demolding cycles can be maintained, and the production efficiency is greatly limited. To further optimize the overall properties of the polyurethane, researchers have explored a variety of modification strategies, mainly including physical blending and chemical modification. Although the polarity and hydrogen bond network of polyurethanes can be regulated to some extent by chemical modification, existing commercial polyurethanes are almost entirely prepared from polyisocyanates and polyols by a stepwise polymerization mechanism, forming a traditional linear or branched topology. The topology of the polymer can significantly affect its physical properties and application potential. For systems that require control of the interfacial migration behavior of small molecules (e.g., internal mold release components), conventional linear polyurethane matrices lack sufficient spatial physical restraint to permanently and stably confine and anchor the mold release active to the interfacial region. In view of the foregoing, there is a need to develop a new polyurethane composite material with integrated design of rapid curing, nano modification and internal demolding and a preparation process thereof. The composite material not only needs to reconstruct a polymer network from a molecular structure layer, solves the problem of mechanical property decline caused by release agent migration and realizes excellent tensile st