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CN-122011320-A - Preparation method of flame-resistant composite yellowing and low-odor polyurethane sponge

CN122011320ACN 122011320 ACN122011320 ACN 122011320ACN-122011320-A

Abstract

The invention discloses a preparation method of flame-resistant composite yellowing and low-odor polyurethane sponge, which relates to the technical field of polyurethane materials, and comprises the steps of preparing a supermolecule functional precursor, a polyol mixture, mixing foaming and curing, wherein the supermolecule functional precursor is in a core-shell structure, the core is a cyclodextrin derivative modified by an amine recognition group, the shell is a hindered phenol unit containing long alkyl chain and connected to the outer edge of the inner core through a thermosensitive linkage, the precursor, polyether polyol, a catalyst, a foam stabilizer and water are mixed to form a polyol mixture, then the polyol mixture and polyisocyanate are mixed and foamed according to a specific isocyanate index, and the target sponge is obtained after curing treatment. When the sponge is laminated and stuck with PVC artificial leather in a flame compounding process, yellowing and peculiar smell can be effectively inhibited, good appearance stability and odor safety are maintained, and excellent rebound resilience and processability are achieved.

Inventors

  • LI LI

Assignees

  • 明珍新材料(南通)有限公司

Dates

Publication Date
20260512
Application Date
20260327

Claims (10)

  1. 1. The preparation method of the flame-resistant composite yellowing low-odor polyurethane sponge is characterized by comprising the following steps of: preparing a supermolecule functional precursor, wherein the supermolecule functional precursor is a core-shell structure molecule formed by an inner core and an outer shell, the inner core is a cyclodextrin derivative modified by an amine recognition group, and the outer shell is a plurality of hindered phenol units containing long alkyl chains and connected to the outer edge of the inner core through thermosensitive linkage; Step two, preparing a polyol mixture, namely mixing polyether polyol, the supermolecular functional precursor prepared in the step one, a catalyst, a foam stabilizer and water at normal temperature, and uniformly stirring to form the polyol mixture, wherein the addition amount of the supermolecular functional precursor is 0.5-2.0% of the total mass of the polyurethane sponge; step three, mixing and foaming, namely rapidly mixing the polyol mixture obtained in the step two with polyisocyanate at an isocyanate index of 1:0.4 to 1:0.6, and injecting the mixture into a mould for free foaming; and fourthly, curing, namely curing the foamed polyurethane sponge product in a curing room at 90-120 ℃ for 1-3 hours, taking out and standing at normal temperature for more than 24 hours to obtain the flame-resistant composite yellowing low-odor polyurethane sponge.
  2. 2. The method for preparing flame resistant composite yellowing low odor polyurethane sponge according to claim 1, wherein in the first step, the amine recognition group is a cyclodextrin derivative modified by a crown ether unit or an aza crown ether unit, the cyclodextrin is at least one selected from α -cyclodextrin, β -cyclodextrin or γ -cyclodextrin, and the modification is grafting of the amine recognition group to a secondary hydroxyl position in a cyclodextrin molecular structure through a chemical bond.
  3. 3. The method for producing a flame resistant, complex yellowing, low odor polyurethane sponge according to claim 1, wherein in the first step, the heat sensitive linkage is selected from at least one of disulfide bond and specific ester bond which is unstable to heat, the long alkyl chain is a linear alkyl group having 8 to 18 carbon atoms, and the hindered phenol unit structure is selected from at least one of 2, 6-di-tert-butyl-4-methylphenol structure and beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate structure.
  4. 4. The method for preparing flame resistant composite yellowing low-odor polyurethane sponge according to claim 1, wherein in the first step, the method for synthesizing the supermolecule functional precursor comprises the following steps: firstly, carrying out a first reaction on cyclodextrin and a modifier containing an amine recognition group under the action of an alkaline catalyst to obtain a modified cyclodextrin intermediate; And then carrying out a second reaction on the modified cyclodextrin intermediate and a compound containing a long alkyl chain and a hindered phenol structure and having a functional group corresponding to a thermosensitive linking bond at the tail end under the action of a condensation catalyst, and purifying to obtain the supermolecule functional precursor.
  5. 5. The method for preparing the flame-resistant composite yellowing low-odor polyurethane sponge according to claim 1, wherein in the second step, the catalyst comprises an amine catalyst and a metal catalyst, wherein the amine catalyst is at least one of propylene glycol solution of bis (dimethylaminoethyl ether) and propylene glycol solution of triethylene diamine, and the metal catalyst is at least one of stannous octoate and dibutyltin dilaurate.
  6. 6. The method for preparing flame-resistant composite yellowing low-odor polyurethane sponge according to claim 1, wherein in the second step, polyether polyol is at least one of polyoxypropylene polyol and polymer polyol with functionality of 2-4 and molecular weight of 1000-6000, foam stabilizer is polysiloxane-alkylene oxide block copolymer non-hydrolytic stabilizer, and the water is added in an amount of 1.5-4.0% of the total mass of the polyol mixture.
  7. 7. The method for preparing flame resistant composite yellowing low-odor polyurethane sponge according to claim 1, wherein in the third step, the polyisocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate or polymethylene polyphenyl polyisocyanate.
  8. 8. The method for preparing flame resistant composite yellowing low-odor polyurethane sponge according to claim 1, wherein in the fourth step, the curing treatment temperature is 100 ℃ and the curing time is 2 hours.
  9. 9. The method for preparing the flame-resistant composite yellowing and low-odor polyurethane sponge according to claim 1, wherein the polyurethane sponge and white PVC leather are subjected to hot pressing treatment at 130 ℃ for 30 seconds and then are aged for 72 hours in a 70 ℃ environment, the color difference value delta E of the surface of the white PVC leather is less than or equal to 0.8, and the color change value delta b of the surface of the white PVC leather is less than or equal to 0.3.
  10. 10. The flame-resistant composite yellowing and low-odor polyurethane sponge suitable for the preparation method of the flame-resistant composite yellowing and low-odor polyurethane sponge as claimed in any one of claims 1 to 9, characterized in that the polyurethane sponge is applied to the preparation of a composite material by laminating and laminating with PVC artificial leather by adopting a flame compounding process, wherein the flame temperature of the flame compounding process is 860-980 ℃, and the compounding linear speed is 15-20 m/min.

Description

Preparation method of flame-resistant composite yellowing and low-odor polyurethane sponge Technical Field The invention relates to the technical field of polyurethane materials, in particular to a preparation method of flame-resistant composite yellowing and low-odor polyurethane sponge. Background Polyurethane sponge is widely applied to the fields of automotive interiors, furniture and home furnishings due to excellent rebound resilience, softness and processability. In these applications, polyurethane sponge and skin materials such as PVC artificial leather are often laminated quickly and efficiently by flame compounding. The process utilizes instant high-temperature flame to melt the sponge surface layer, thereby realizing the adhesion with leather. However, the extremely high temperature conditions in flame compounding processes also become a serious technical challenge. There have been many attempts in the art to improve the appearance stability and odor of polyurethane articles. For example, in solving the problem of sponge yellowing, some technical solutions focus on adding conventional antioxidant and light stabilizer systems to resist light and thermo-oxidative aging at normal temperature. While in terms of odor control, some prior art attempts have been directed to reducing the release of small molecule volatiles from foams under conventional use conditions by employing specific polyether polyol mixtures and controlling the isocyanate index. However, these prior art solutions have significant limitations. Firstly, aiming at the yellowing problem, the common antioxidant is extremely easy to decompose or lose efficacy at the instant high temperature faced by flame compounding, so that not only can the migration of substances such as amines released by pyrolysis of a sponge matrix be effectively prevented, but also the decomposition product of the common antioxidant can become a new chromophore. Secondly, aiming at the odor problem, the formula design aiming at reducing the normal odor cannot cope with the small molecular odor substances generated by a new round of intense chemical reaction initiated by the flame at high temperature. More importantly, the yellowing and smell are treated as two independent problems in the prior art, and the mode of physically blending a plurality of functional auxiliary agents is adopted, so that the components are possibly poor in compatibility, delayed in response or mutually interfered under extreme conditions, and synergistic, efficient and stable protection is difficult to form under a specific and severe space-time scene of flame compounding. Therefore, the invention aims to solve the technical problem of how to design the polyurethane sponge special for the flame compounding process, so that the polyurethane sponge can fundamentally inhibit migration and pollution of alkaline amine substances and oxidation chromophores generated by thermal oxidation in the sponge to the surface of PVC leather when the polyurethane sponge is subjected to the instantaneous high-temperature effect of flame, thereby effectively preventing irreversible yellowing of a leather interface after compounding and simultaneously controlling peculiar smell generated in the process. The key to this problem is the need for a dynamic mechanism that can intelligently respond to high flame temperatures and actively exert synergistic interception on the contaminant migration path, rather than simple static addition of multiple adjuvants. Disclosure of Invention The invention aims to make up the defects of the prior art, provides a preparation method of flame-resistant composite yellowing and low-odor polyurethane sponge, and provides a polyurethane sponge preparation scheme adapting to a flame composite process by designing a supermolecular functional precursor with a core-shell structure, capturing amine substances generated at a high temperature by a flame composite, releasing a hindered phenol unit by a shell at a high temperature through a thermosensitive linking bond to form dynamic synergistic protection, and inhibiting yellowing and odor from a source. The invention provides a preparation method of flame-resistant composite yellowing low-odor polyurethane sponge for solving the technical problems, which comprises the following steps: preparing a supermolecule functional precursor, wherein the supermolecule functional precursor is a core-shell structure molecule formed by an inner core and an outer shell, the inner core is a cyclodextrin derivative modified by an amine recognition group, and the outer shell is a plurality of hindered phenol units containing long alkyl chains and connected to the outer edge of the inner core through thermosensitive linkage; Step two, preparing a polyol mixture, namely mixing polyether polyol, the supermolecular functional precursor prepared in the step one, a catalyst, a foam stabilizer and water at normal temperature, and uniformly stirring to form the pol