Flame-retardant skin-friendly polyurethane sponge with synergy of in-situ reaction and bio-enzyme catalysis

Abstract

The invention relates to a flame-retardant skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme catalysis synergism. The water-based polyurethane foam is prepared from the following components: polyether polyol, diphenylmethane diisocyanate or toluene diisocynate, a chain extender, a high-efficiency foam stabilizer, a high-efficiency composite catalyst, water and ethanolamine phosphate, ethanolamine phosphate is added into water in advance, and then all the raw materials are mixed for polymerization foaming; after curing, spraying a spraying liquid consisting of phosphoethanolamine, regenerated protein and transglutaminase to generate a nano protein film, and synchronously performing vacuum suction to keep sponge pores unblocked. The preparation method has the advantages that a small amount of ethanolamine phosphate is added before polymerization foaming to serve as a phosphorus-nitrogen synergistic flame retardant and also serve as a catalytic cross-linking agent to participate in a reaction during polymerization, biological enzyme is added for catalysis after curing is finished, and the skin-friendly PU sponge with excellent flame retardance is prepared through in-situ polymerization reaction and biological enzyme enzymatic polymerization cooperation, and the sponge performance is not affected; the raw materials of the flame retardant come from biomass products and are environment-friendly and safe.

Description

Technical Field

[0001] This invention relates to the field of home sponge preparation, specifically to a flame-retardant and skin-friendly polyurethane sponge produced by in-situ reaction and bio-enzyme synergy. Background Technology

[0002] Polyurethane (PU) foam, as a high-performance polymer material, has a wide range of applications. It is widely used in high-end automotive interiors, advanced composite materials, flocked fabrics, skincare products, printer consumables, filtration, toys, and other industries. In the home furnishing sector, polyurethane foam can be used to make mattresses, pillowcases, and other household items. However, the flammability of polyurethane poses a serious threat to human life and property safety. Researchers have conducted much fruitful work on the flame-retardant modification of polyurethane, and with increasing environmental awareness, halogenated flame retardants, which pose potential pollution risks and secondary hazards, are gradually being replaced.

[0003] In existing technologies, the addition of flame retardants mainly employs a simple physical blending method. A large amount is required to produce a flame-retardant effect, but this large amount can also negatively impact the performance of PU. If reactive flame retardants are used, high addition amounts are often necessary to improve the flame retardancy rating. However, excessive addition of flame retardants can severely damage the cell structure of polyurethane foam, leading to hardening, decreased elasticity, and significant deterioration of key physical and mechanical properties such as tensile strength and compression set. Furthermore, the foam's skin-friendliness is also unsatisfactory. In addition, flame retardants still pose environmental and safety concerns. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a flame-retardant and skin-friendly polyurethane sponge that combines in-situ reaction and bio-enzyme catalysis. This invention can solve the problems in the prior art where the amount of physically blended flame retardants and reactive flame retardants used is too large, resulting in the deterioration of polyurethane sponge performance, unsatisfactory skin-friendliness, and insufficient environmental protection and safety of flame retardants.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: a flame-retardant and skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme synergy, composed of the following components by weight: 90-110 parts of polyether polyol, 50-90 parts of MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, 0.05-0.5 parts of chain extender, 0.05-4 parts of high-efficiency foam stabilizer, 0.05-0.5 parts of high-efficiency composite catalyst, 1-5 parts of water, and 0.1-1 parts of ethanolamine phosphate; Polyurethane foam preparation: During the polymerization of isocyanate and polyether polyol, ethanolamine phosphate is added to water before polymerization and foaming. Then, the polyether polyol, MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, chain extender, high-efficiency foam stabilizer, high-efficiency composite catalyst, external foaming agent, and water with added ethanolamine phosphate are mixed and stirred for polymerization and foaming. After the curing process is complete, a spray consisting of ethanolamine phosphate, regenerated protein, and transglutaminase is sprayed. Through the catalytic action of transglutaminase, a nano-protein membrane grafted with ethanolamine phosphate is generated, and the micropores of the sponge are kept open by vacuum suction.

[0006] Furthermore, the polyurethane foam also includes 0-6 parts of an external foaming agent; The chain extender is a low molecular weight compound of polyol or diamine; The high-efficiency foam stabilizer is an organosilicon foam stabilizer or a polysiloxane-polyoxyolefin mosaic copolymer. The highly efficient composite catalyst is a complex of a tin-based catalyst and an amine-based catalyst; The external foaming agent is a physical foaming agent used for polyurethane foaming; The polyether polyol is a polyether used for polyurethane foaming.

[0007] Furthermore, during the spraying of the spray liquid after the curing process, vacuum suction is performed simultaneously. Through this simultaneous spraying and suction, a nano-protein membrane containing phosphate ethanolamine grafted onto the inner wall of the sponge's pores is also generated, ensuring that the inner wall of the sponge's pores is covered with spray liquid. Vacuum suction also ensures that the pores remain unobstructed.

[0008] Furthermore, the preparation steps of the polyurethane foam are as follows: When S1, isocyanate and polyether polyol are polymerized, ethanolamine phosphate is added to water in advance. Then, polyether polyol, MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, chain extender, high-efficiency foam stabilizer, high-efficiency composite catalyst, external foaming agent, and water with added ethanolamine phosphate are mixed and stirred to carry out polymerization and foaming. S2. The foaming process is an open, continuous, low-pressure flat foam. The raw material is sprayed through the foaming nozzle to the foaming system conveying device, and foaming and conveying are carried out simultaneously. At the same time, the conveying device is limited to control the width of the polyurethane foam. The thickness of the polyurethane foam is controlled by the flow rate of the raw material and the conveying speed. The output of the mixing head is adjusted to meet the width and thickness requirements of the foam. The height and curvature of the top of the foam are controlled by adjusting the conveying speed and the position of the drop plate to obtain the required foam flow pattern. S3. After the foam is demolded, the intentionally excessive isocyanate groups in the formula continue to react with moisture and active hydrogen on its own polymer chains to form a higher density cross-linked network and complete the curing process. S4. After the curing is completed, a spray solution consisting of ethanolamine phosphate, regenerated protein and transglutaminase is sprayed, and vacuum suction is performed simultaneously. Through the catalytic action of transglutaminase, a nano-protein film containing ethanolamine phosphate grafts is generated on the surface of the sponge and the inner wall of the pores. Vacuum suction is performed to ensure that the pores are unobstructed.

[0009] Furthermore, in the spray liquid, the regenerated protein is one of the following: hydrolyzed protein from waste silk fibroin, sericin from degummed silk, hydrolyzed protein from waste wool, and gelatin protein. The regenerated protein is a protein freeze-dried powder solution with a concentration of 10 g / L. The ethanolamine phosphate concentration was 100 mmol / L; The transglutaminase is 30 U / g protein; The spray liquid is reacted at 50°C for 1-2 hours after spraying, the flow rate of the spray liquid is 10-15 L / min, and the conveying speed of the polyurethane sponge is 50-60 m / min.

[0010] Furthermore, the spray solution also includes a 0.05 mol / L Tris-HCl buffer solution with a pH of 7.6.

[0011] The advantages of this invention are: adding a small amount of ethanolamine phosphate before polymerization and foaming not only acts as a phosphorus-nitrogen synergistic flame retardant but also as a catalytic crosslinking agent, participating in the reaction during polymerization; and adding bio-enzyme catalysis after the curing process following foaming, through the synergistic effect of in-situ polymerization reaction and bio-enzyme-catalyzed polymerization, a skin-friendly PU sponge with excellent flame retardant properties is prepared, further improving the flame retardant effect. Because the amount of flame retardant ethanolamine phosphate added during in-situ foaming polymerization is small, it does not affect the performance of the sponge foam; The spraying liquid and vacuum suction are linked. The outer layer of the sponge and the inner wall of the cell are loaded with nano protein film. Vacuum suction ensures that the cell is open and does not affect the breathability of the sponge. The PU sponge loaded with nano protein film has good skin-friendliness. The flame retardant is biomass-derived ethanolamine phosphate. The raw material for the flame retardant comes from biomass products, making it environmentally friendly and safe. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. The following embodiments will enable those skilled in the art to more fully understand this invention, but do not limit the invention to the scope of the described embodiments.

[0013] This specific embodiment adopts the following technical solution: a flame-retardant and skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme synergy, composed of the following components by weight: 90-110 parts of polyether polyol, 50-90 parts of MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, 0.05-0.5 parts of chain extender, 0.05-4 parts of high-efficiency foam stabilizer, 0.05-0.5 parts of high-efficiency composite catalyst, 1-5 parts of water, and 0.1-1 parts of ethanolamine phosphate.

[0014] Polyurethane foam also includes 0-6 parts of external foaming agent; Chain extenders are low-molecular-weight compounds such as polyols or diamines; High-efficiency foam stabilizers are silicone foam stabilizers or polysiloxane-polyoxyolefin mosaic copolymers; The highly efficient composite catalyst is a complex of tin-based catalysts and amine-based catalysts; External foaming agents are physical foaming agents used for polyurethane foaming, such as dichloromethane; Polyether polyols are polyethers used in polyurethane foaming.

[0015] The preparation steps of polyurethane foam are as follows: When S1, isocyanate and polyether polyol are polymerized, ethanolamine phosphate is added to water in advance. Then, polyether polyol, MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, chain extender, high-efficiency foam stabilizer, high-efficiency composite catalyst, external foaming agent, and water with added ethanolamine phosphate are mixed and stirred to carry out polymerization and foaming. S2. The foaming process is an open, continuous, low-pressure flat foam. The raw material is sprayed through the foaming nozzle to the foaming system conveying device, and foaming and conveying are carried out simultaneously. At the same time, the conveying device is limited to control the width of the polyurethane foam. The thickness of the polyurethane foam is controlled by the flow rate of the raw material and the conveying speed. The output of the mixing head is adjusted to meet the width and thickness requirements of the foam. The height and curvature of the top of the foam are controlled by adjusting the conveying speed and the position of the drop plate to obtain the required foam flow pattern. S3. After the foam is demolded, the excess isocyanate groups in the formula continue to react with moisture and active hydrogen on its own polymer chains to form a higher density cross-linked network and complete the curing process. S4. After the curing is complete, spray a liquid consisting of ethanolamine phosphate, regenerated protein and transglutaminase, and simultaneously vacuum suction. Spray from above the sponge and suction from below. Through the catalytic action of transglutaminase and the simultaneous spraying and suction, a nano-protein film containing ethanolamine phosphate grafts is generated on the surface of the sponge and the inner wall of the pores. Vacuum suction ensures that the pores are unobstructed.

[0016] In the spray liquid, the regenerated protein is one of the following: hydrolyzed protein from waste silk fibroin, sericin from degummed silk, hydrolyzed protein from waste wool, and gelatin protein. The regenerated protein is a protein freeze-dried powder solution with a concentration of 10 g / L. The concentration of ethanolamine phosphate was 100 mmol / L. Transglutaminase is 30 U / g protein; The spray liquid is reacted at 50°C for 1-2 hours after spraying, the flow rate of the spray liquid is 10-15 L / min, and the conveying speed of the polyurethane sponge is 50-60 m / min.

[0017] The spray solution also includes a 0.05 mol / L Tris-HCl buffer solution with a pH of 7.6.

[0018] Example 1: Polyurethane foam is produced by polymerizing isocyanate and polyether polyol using the above method and then spraying the foam with a spraying liquid. The polyurethane foam is composed of the following components by weight: 100 parts polyether polyol, 65 parts MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, 0.3 parts chain extender, 3 parts high-efficiency foam stabilizer, 0.45 parts high-efficiency composite catalyst, 3 parts water, and 0.5 parts ethanolamine phosphate.

[0019] The flow rate of the injection liquid is 10L / min, and the conveying speed of the polyurethane sponge is 50m / min.

[0020] Example 2: The only difference between Example 2 and Example 1 is that the injection flow rate is 15 L / min.

[0021] Example 3: The only difference between Example 3 and Example 1 is that Example 3 contains 1 part of ethanolamine phosphate.

[0022] Example 4: The only difference between Example 4 and Example 1 is that: 1 part of ethanolamine phosphate and 15 L / min of spray liquid flow rate.

[0023] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that: 0% ethanolamine phosphate and 0% flow rate of the injection liquid.

[0024] Comparative Example 2: The only difference between Comparative Example 2 and Example 1 is that the injection flow rate is 0.

[0025] Comparative Example 3: The only difference between Comparative Example 3 and Example 1 is that: 1 part of ethanolamine phosphate and 0 flow rate of the spray liquid.

[0026] Comparative Example 4: The only difference between Comparative Example 4 and Example 1 is that: 2 parts of ethanolamine phosphate and 0 flow rate of the injection liquid.

[0027] The flame-retardant and skin-friendly polyurethane sponges prepared by in-situ reaction and bio-enzyme synergy in the above embodiments and comparative examples were subjected to flame-retardant oxygen index test, hardness test, and air permeability test. The test results are shown in Table 1.

[0028] Table 1. Test results of flame retardant oxygen index, hardness, and air permeability of the sponges prepared in Examples 1-4 and Comparative Examples 1-4. Addition of ethanolamine phosphate (parts) Fluid usage (L / min) Hardness index (ILD) Flame retardant oxygen index % <![CDATA[Air permeability (dm 3 / S)]]> Example 1 0.5 10 12.23 33.8 0.46 Example 2 0.5 15 12.23 35.5 0.46 Example 3 1 10 12.22 37.2 0.45 Example 4 1 15 12.22 38.9 0.45 Comparative Example 1 0 0 12.24 20.5 0.46 Comparative Example 2 0.5 0 12.24 26.3 0.46 Comparative Example 3 1 0 12.23 29.4 0.45 Comparative Example 4 2 0 9.26 35.1 0.35 Conclusion: According to the test data in Table 1, in Examples 1-4, a small amount of ethanolamine phosphate was added before polymerization and foaming, and the spraying liquid was sprayed after the curing process following foaming. Through the addition of bio-enzyme catalysis, a nano-protein film containing ethanolamine phosphate grafted on the surface and pore walls of the sponge was generated. The PU sponge prepared in these examples showed significantly better flame retardant performance than Comparative Examples 1-3, while the sponge remained soft and had good air permeability. Comparative Example 4 used a larger amount of ethanolamine phosphate but did not spray the spraying liquid. Although it had a good flame retardant effect, it was still not as good as in Examples 2-4, and the sponge hardness index changed greatly, and the sponge air permeability deteriorated. This invention adds a small amount of ethanolamine phosphate before polymerization and foaming. It acts not only as a phosphorus-nitrogen synergistic flame retardant but also as a catalytic crosslinking agent, participating in the reaction during polymerization. Furthermore, after the curing process following foaming, bio-enzymes are added for catalysis. Through the synergistic effect of in-situ polymerization and bio-enzyme-catalyzed polymerization, a skin-friendly PU sponge with excellent flame retardant properties is prepared, further improving the flame retardant effect. Since the amount of flame retardant ethanolamine phosphate added during in-situ foaming polymerization is small, it does not affect the soft foam performance of the sponge. The combined spraying of the spray liquid and vacuum suction creates a nanoscale protein film on the outer layer and inner pore walls of the sponge. Vacuum suction also ensures that the pores of the sponge are unobstructed, without affecting the air permeability of the sponge. The protein-loaded sponge has good skin-friendliness.

[0029] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant and skin-friendly polyurethane sponge with synergistic in-situ reaction and bio-enzyme catalysis, characterized in that: It is composed of the following components by weight: 90-110 parts of polyether polyol, 50-90 parts of MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, 0.05-0.5 parts of chain extender, 0.05-4 parts of high-efficiency foam stabilizer, 0.05-0.5 parts of high-efficiency composite catalyst, 1-5 parts of water, and 0.1-1 parts of ethanolamine phosphate; Polyurethane foam preparation: During the polymerization of isocyanate and polyether polyol, ethanolamine phosphate is added to water before polymerization and foaming. Then, the polyether polyol, MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, chain extender, high-efficiency foam stabilizer, high-efficiency composite catalyst, external foaming agent, and water with added ethanolamine phosphate are mixed and stirred for polymerization and foaming. After the curing process is complete, a spray consisting of ethanolamine phosphate, regenerated protein, and transglutaminase is sprayed. Through the catalytic action of transglutaminase, a nano-protein membrane grafted with ethanolamine phosphate is generated, and the micropores of the sponge are kept open by vacuum suction.

2. The flame-retardant and skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme synergy as described in claim 1, characterized in that: The polyurethane foam also includes 0-6 parts of an external foaming agent; The chain extender is a low molecular weight compound of polyol or diamine; The high-efficiency foam stabilizer is an organosilicon foam stabilizer or a polysiloxane-polyoxyolefin mosaic copolymer; the high-efficiency composite catalyst is a composite of a tin catalyst and an amine catalyst; The external foaming agent is a physical foaming agent used for polyurethane foaming; The polyether polyol is a polyether used for polyurethane foaming.

3. The flame-retardant and skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme synergy as described in claim 1, characterized in that: After the curing process is complete, the spray liquid is sprayed simultaneously with vacuum suction. Through this simultaneous spraying and suction, a nano-protein membrane containing phosphate ethanolamine grafted onto the inner wall of the sponge's pores is also generated, ensuring that the spray liquid is present on the inner wall of the sponge's pores. The vacuum suction also ensures that the pores remain unobstructed.

4. The flame-retardant and skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme synergy as described in claim 1, characterized in that: The preparation steps of the polyurethane foam are as follows: When S1, isocyanate and polyether polyol are polymerized, ethanolamine phosphate is added to water in advance. Then, polyether polyol, MDI diphenylmethane diisocyanate or TDI toluene diisocyanate, chain extender, high-efficiency foam stabilizer, high-efficiency composite catalyst, external foaming agent, and water with added ethanolamine phosphate are mixed and stirred to carry out polymerization and foaming. S2. The foaming process is an open, continuous, low-pressure flat foam. The raw material is sprayed through the foaming nozzle to the foaming system conveying device, and foaming and conveying are carried out simultaneously. At the same time, the conveying device is limited to control the width of the polyurethane foam. The thickness of the polyurethane foam is controlled by the flow rate of the raw material and the conveying speed. The output of the mixing head is adjusted to meet the width and thickness requirements of the foam. The height and curvature of the top of the foam are controlled by adjusting the conveying speed and the position of the drop plate to obtain the required foam flow pattern. S3. After the foam is demolded, the intentionally excessive isocyanate groups in the formula continue to react with moisture and active hydrogen on its own polymer chains to form a higher density cross-linked network and complete the curing process. S4. After the curing is completed, a spray solution consisting of ethanolamine phosphate, regenerated protein and transglutaminase is sprayed, and vacuum suction is performed simultaneously. Through the catalytic action of transglutaminase, a nano-protein film containing ethanolamine phosphate grafts is generated on the surface of the sponge and the inner wall of the pores. Vacuum suction is performed to ensure that the pores are unobstructed.

5. The flame-retardant and skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme synergy as described in claim 1, characterized in that: The regenerated protein in the spray liquid is one of the following: hydrolyzed protein from waste silk fibroin, sericin from degummed silk, hydrolyzed protein from waste wool, and gelatin protein. The regenerated protein is a protein freeze-dried powder solution with a concentration of 10 g / L. The phosphate ethanolamine concentration was 100 mmol / L; the transglutaminase concentration was 30 U / g protein. The spray liquid is reacted at 50°C for 1-2 hours after spraying, the flow rate of the spray liquid is 10-15 L / min, and the conveying speed of the polyurethane sponge is 50-60 m / min.

6. The flame-retardant and skin-friendly polyurethane sponge according to claim 1, characterized in that: The spray solution also includes a 0.05 mol / L Tris-HCl buffer solution with a pH of 7.6.