Antibacterial polyurethane foam dressing as well as preparation method and application thereof

Abstract

The invention discloses an antibacterial polyurethane foam dressing as well as a preparation method and application thereof, and is characterized in that the dressing is of a multi-layer structure, the outer layer is a polyurethane foam layer, and the inner layer is a chitosan-based adhesive layer; the polyurethane foam layer is prepared from the following components in parts by weight through a foaming process: 100 parts of polyether polyol, 40-50 parts of polyisocyanate, 50-70 parts of a foaming agent, 0.2-0.4 part of a catalyst, 0.02-0.3 part of a foam stabilizer and 0.1-0.9 part of antibacterial alcohol; the chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 50-100 parts of chitosan, 200-300 parts of deionized water, 5-10 parts of a cross-linking agent, 3-8 parts of a plasticizer and 0.5-2 parts of antibacterial alcohol, can be used for preparing medical dressings and wound care products, and has the advantages of mechanical support and continuous bacteriostasis functions.

Description

TECHNICAL FIELD

[0001] The present application relates to a foam dressing, in particular to an antibacterial polyurethane foam dressing and its preparation method and application. BACKGROUND

[0002] Dressing is a medical material used to protect the wound from the outside environment and provide a suitable environment for wound healing. Traditional wound dressings such as cotton and gauze are well known for their low cost, simplicity and effectiveness. However, as people's requirements for wound dressings increase, their shortcomings become more and more obvious, such as poor air permeability, easy adhesion to the wound, poor moisture retention, easy drying, inability to absorb exudate for a long time, need to be replaced frequently, and lack of antibacterial ability. With the development of modern medicine, some artificial and natural polymers have been made into wound dressings that can improve wound healing. However, biological materials still have limitations such as poor mechanical properties, low water absorption, and poor anti-infection performance. Suitable mechanical properties are the basic requirement for wound dressings to maintain their flexibility and integrity when removed. Good hydrophilicity and water absorption can provide a suitable moist microenvironment for the wound and promote wound healing. In view of the above problems, polyurethane foam wound dressing is a good choice. Polyurethane has good mechanical properties and can be well fitted to the wound site. When removed, it will not adhere to the wound, can prevent secondary bleeding, and has no immunogenicity. In addition, polyurethane is widely used in the field of medical materials, and it not only has low cost, but also has mature technology and various modification methods.

[0003] For polyurethane materials, the surface itself is prone to adhere to bacteria. Therefore, it is necessary to modify the antibacterial function of polyurethane foam dressing. However, the antibacterial agents currently used are mostly inorganic or organic antibacterial agents, and these antibacterial agents have problems such as leaching, inability to long-term antibacterial, and high cytotoxicity. SUMMARY

[0004] The technical problem to be solved by the present application is to provide an antibacterial polyurethane foam dressing with mechanical support and sustained antibacterial function, and its preparation method and application.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: an antibacterial polyurethane foam dressing, which has a multi-layer structure, an outer layer of a polyurethane foam layer, and an inner layer of a chitosan-based adhesive layer; the polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts of polyether polyol, 40-50 parts of polyisocyanate, 50-70 parts of foaming agent, 0.2-0.4 parts of catalyst, 0.02-0.3 parts of foam stabilizer, and 0.1-0.9 parts of antibacterial alcohol; the chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 50-100 parts of chitosan, 200-300 parts of deionized water, 5-10 parts of cross-linking agent, 3-8 parts of plasticizer, and 0.5-2 parts of antibacterial alcohol. wherein the antibacterial alcohol comprises one or more of linalool, citronellol, nerolidol, carveol, dihydromyrcenol, vetiverol and lauryl alcohol, and the purity of the antibacterial alcohol is not less than 90%.

[0006] Furthermore, the polyether polyol is a medium-chain polyol with a molecular weight of 500-2000; the polyisocyanate is toluene diisocyanate, diphenylmethane diisocyanate or isophorone diisocyanate.

[0007] Furthermore, the catalyst is an organic tin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft foam silicone oil or lauryl alcohol.

[0008] Furthermore, the chitosan has a degree of deacetylation of 75% to 95% and a viscosity-average molecular weight of 50 to 300 kDa; the crosslinking agent is one of glutaraldehyde and chitosan-specific crosslinking agent CS-01; and the plasticizer is one of glycerol and sorbitol.

[0009] Furthermore, the density of the polyurethane foam layer is 30-60kg / m³, the tensile strength is not less than 1.2MPa, and the elongation at break is not less than 250%; the peel strength of the chitosan-based adhesive layer is 0.03-0.06MPa, and the antibacterial rate against Staphylococcus aureus and Escherichia coli is not less than 95%.

[0010] The present invention also provides a method for preparing the antibacterial polyurethane foam dressing, comprising the following steps: Step 1. Preparation of polyurethane foam: Add dry polyether polyol to a reaction vessel, heat to 60-80°C and stir for 1-2 hours, add polyisocyanate, add catalyst, foam stabilizer and antibacterial alcohol 15 minutes before the end of stirring, stir evenly and pour into a mold, add foaming agent, stir at high speed for 4-5 seconds, and then let it stand for foaming and molding. The foaming time is 4-8 hours; Step 2, preparation of chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinking agent and a plasticizer, stirring evenly, adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution; Step 3: Dressing assembly: evenly apply the chitosan-based adhesive layer solution on the surface of the release paper to a thickness of 20-30 μm. After drying, cut and adhere to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

[0011] Furthermore, in the preparation of the polyurethane foam, the drying temperature of the dried polyether polyol is 110° C., the drying time is 2 hours, and the stirring speed is 1200 r / min.

[0012] Furthermore, in the preparation of the chitosan-based adhesive layer, the stirring speed during the dissolution of chitosan is 300-500 r / min, and the stirring time is 1-2 h; the stirring time after adding the crosslinker and plasticizer is 30-45 min; and the stirring time after adding the antibacterial alcohol is 15-20 min.

[0013] The present invention also provides the use of the antibacterial polyurethane foam dressing in the field of wound dressing, which is particularly suitable for various wounds that require long-term protection, infection prevention and healing promotion, including acute wounds and chronic wounds.

[0014] The present invention also provides the use of the antibacterial polyurethane foam dressing in the preparation of medical dressings and wound care products.

[0015] The present invention also provides use of the antibacterial polyurethane foam dressing in preparing an Escherichia coli inhibition product.

[0016] Compared with the existing technology, the advantages of the present invention are: the present invention provides an antibacterial polyurethane foam dressing and its preparation method and application. The antibacterial polyurethane foam dressing achieves synergistic protection through an innovative double-layer structure: the outer polyurethane foam layer is loaded with natural plant-derived antibacterial alcohol, which has both mechanical support and continuous antibacterial functions; the inner high-deacetylation chitosan adhesive layer is equipped with homologous antibacterial ingredients, which provides biocompatible adhesion and directly kills wound pathogens. Its breakthrough lies in: ① The use of chemically bonded natural antibacterial agents to avoid the leaching toxicity and failure risks of traditional antibacterial agents; ② The integrated process simultaneously completes foaming and precise coating of the adhesive layer, greatly simplifying the production process; ③ Chitosan cross-linking technology enhances biological activity and promotes wound healing. This design effectively balances antibacterial efficacy, material safety and clinical applicability, and provides an innovative solution for the care of infectious wounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a picture of Escherichia coli colonies under the action of the antibacterial polyurethane foam dressing in Example 1; Figure 2 This is a picture of Escherichia coli colonies under the action of the antibacterial polyurethane foam dressing in Example 2; Figure 3 This is a picture of Escherichia coli colonies under the action of the antibacterial polyurethane foam dressing in Example 3; Figure 4 This is the colony diagram of Escherichia coli under the action of antibacterial polyurethane foam dressing in the control group. DETAILED DESCRIPTION

[0018] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. Specific embodiments

[0019] An antibacterial polyurethane foam dressing, which has a multi-layer structure, an outer layer of a polyurethane foam layer, and an inner layer of a chitosan-based adhesive layer; the polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts of polyether polyol, 40-50 parts of polyisocyanate, 50-70 parts of foaming agent, 0.2-0.4 parts of catalyst, 0.02-0.3 parts of foam stabilizer, and 0.1-0.9 parts of antibacterial alcohol; the chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 50-100 parts of chitosan, 200-300 parts of deionized water, 5-10 parts of cross-linking agent, 3-8 parts of plasticizer, and 0.5-2 parts of antibacterial alcohol. wherein the antimicrobial alcohol comprises one or more of linalool, citronellol, nerolidol, carveol, dihydromyrcenol, vetiverol, and lauryl alcohol, and the purity of the antimicrobial alcohol is not less than 90%. The preparation method thereof comprises the following steps: Step 1, polyurethane foam preparation: add dry polyether polyol to a reaction vessel, heat to 60-80°C and stir for 1-2 hours, add polyisocyanate, add catalyst, foam stabilizer and antibacterial alcohol 15 minutes before the end of stirring, stir evenly and pour into a mold, add foaming agent, stir at high speed for 4-5 seconds, and then stand for foaming and molding. The foaming time is 4-8 hours. The drying temperature of the dry polyether polyol is 110°C, the drying time is 2 hours, and the stirring speed is 1200 r / min. Step 2, preparing a chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinker and a plasticizer, stirring evenly, then adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution. In the preparation of the chitosan-based adhesive layer, the stirring speed during the chitosan dissolution is 300-500 rpm, and the stirring time is 1-2 hours; the stirring time after adding the crosslinker and plasticizer is 30-45 minutes; and the stirring time after adding the antimicrobial alcohol is 15-20 minutes; Step 3: Dressing assembly: evenly apply the chitosan-based adhesive layer solution on the surface of the release paper to a thickness of 20-30 μm. After drying, cut and adhere to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

[0020] The polyether polyol is a medium-chain polyol with a molecular weight of 500-2000; the polyisocyanate is toluene diisocyanate, diphenylmethane diisocyanate, or isophorone diisocyanate. The catalyst is an organotin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft foam silicone oil or lauryl alcohol. The chitosan has a degree of deacetylation of 75%-95% and a viscosity-average molecular weight of 50-300 kDa; the crosslinker is glutaraldehyde or chitosan-specific crosslinker CS-01; and the plasticizer is glycerol or sorbitol. The polyurethane foam layer has a density of 30-60 kg / m³, a tensile strength of no less than 1.2 MPa, and an elongation at break of no less than 250%. The chitosan-based adhesive layer has a peel strength of 0.03-0.06 MPa and an antibacterial rate of no less than 90% against Staphylococcus aureus and Escherichia coli.

[0021] Example 1 An antibacterial polyurethane foam dressing has a multi-layer structure, with an outer polyurethane foam layer and an inner chitosan-based adhesive layer. The polyurethane foam layer is prepared by a foaming process using the following components in parts by weight: 100 parts polyether polyol, 40 parts polyisocyanate, 50 parts blowing agent, 0.2 parts catalyst, 0.02 parts foam stabilizer, and 0.1 parts antibacterial alcohol. The chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 50 parts chitosan, 200 parts deionized water, 5 parts cross-linking agent, 3 parts plasticizer, and 0.5 parts antibacterial alcohol. The antibacterial alcohol is a mixture of linalool and citronellol. The preparation method comprises the following steps: Step 1, polyurethane foam preparation: add dry polyether polyol to a reaction vessel, heat to 60°C and stir for 1 minute, add polyisocyanate, add catalyst, foam stabilizer and antibacterial alcohol 15 minutes before the end of stirring, stir evenly and pour into a mold, add foaming agent, stir at high speed for 4 seconds, and then stand for foaming molding, and the foaming time is 4 hours; wherein the drying temperature of the dry polyether polyol is 110°C, the drying time is 2 hours, and the stirring speed is 1200 r / min; Step 2, preparation of a chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinker and a plasticizer, stirring evenly, adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution, wherein in the preparation of the chitosan-based adhesive layer, the stirring speed during the dissolution of chitosan is 300 r / min, and the stirring time is 1 hour; the stirring time after adding the crosslinker and plasticizer is 30 minutes; and the stirring time after adding the antimicrobial alcohol is 15 minutes; Step 3, dressing assembly: evenly apply the chitosan-based adhesive layer solution on the surface of the release paper, controlling the thickness to 20 microns, cut it after drying and adhere it to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

[0022] The polyether polyol is a medium-chain polyol with a molecular weight of 500; the polyisocyanate is toluene diisocyanate. The catalyst is an organotin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft foam silicone oil. The chitosan has a deacetylation degree of 75% and a viscosity-average molecular weight of 50 kDa; the crosslinking agent is glutaraldehyde; and the plasticizer is glycerol. The polyurethane foam layer has a density of 30 kg / m³, a tensile strength of 1.2 MPa, and an elongation at break of 250%. The peel strength of the chitosan-based adhesive layer is 0.03 MPa, and the antibacterial rate against Escherichia coli is 91%. The antibacterial effect is as follows: Figure 1 shown.

[0023] Example 2 An antibacterial polyurethane foam dressing has a multi-layer structure, an outer polyurethane foam layer, and an inner chitosan-based adhesive layer. The polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts polyether polyol, 45 parts polyisocyanate, 60 parts blowing agent, 0.3 parts catalyst, 0.1 parts foam stabilizer, and 0.4 parts antibacterial alcohol. The chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 70 parts chitosan, 250 parts deionized water, 8 parts cross-linking agent, 5 parts plasticizer, and 1 part antibacterial alcohol. The antibacterial alcohol is a mixture of carveol and dihydromyrcenol. The preparation method comprises the following steps: Step 1, polyurethane foam preparation: dry polyether polyol is added to a reaction vessel, heated to 70°C and stirred for 1.5 hours, polyisocyanate is added, and 15 minutes before the end of stirring, a catalyst, foam stabilizer and antibacterial alcohol are added, stirred evenly and poured into a mold, a foaming agent is added, and high-speed stirring is performed for 4.5 seconds, and then allowed to stand for foaming and molding. The foaming time is 6 hours; wherein the drying temperature of the dry polyether polyol is 110°C, the drying time is 2 hours, and the stirring speed is 1200 r / min; Step 2, preparation of a chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinker and a plasticizer, stirring evenly, adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution, wherein in the preparation of the chitosan-based adhesive layer, the stirring speed during the dissolution of chitosan is 400 r / min, and the stirring time is 1.5 h; the stirring time after adding the crosslinker and plasticizer is 40 min; and the stirring time after adding the antimicrobial alcohol is 18 min; Step 3, dressing assembly: evenly apply the chitosan-based adhesive layer solution on the surface of the release paper, controlling the thickness to 25 microns, cut it after drying and adhere it to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

[0024] The polyether polyol is a medium-chain polyol with a molecular weight of 1000; the polyisocyanate is diphenylmethane diisocyanate. The catalyst is an organotin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft foam silicone oil or lauryl alcohol. The chitosan has a degree of deacetylation of 85% and a viscosity-average molecular weight of 200 kDa; the crosslinker is CS-01, a chitosan-specific crosslinker; and the plasticizer is sorbitol. The polyurethane foam layer has a density of 50 kg / m³, a tensile strength of 1.5 MPa, and an elongation at break of 280%. The chitosan-based adhesive layer has a peel strength of 0.05 MPa, an antibacterial rate of 95% against Escherichia coli, and an antibacterial effect of 95% on bacterial colonies. Figure 2 shown.

[0025] Example 3 An antibacterial polyurethane foam dressing has a multi-layer structure, an outer polyurethane foam layer, and an inner chitosan-based adhesive layer. The polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts of polyether polyol, 50 parts of polyisocyanate, 70 parts of foaming agent, 0.4 parts of catalyst, 0.3 parts of foam stabilizer, and 0.9 parts of antibacterial alcohol. The chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 100 parts of chitosan, 300 parts of deionized water, 10 parts of cross-linking agent, 8 parts of plasticizer, and 2 parts of antibacterial alcohol. The antibacterial alcohol is a mixture of vetiverol and lauryl alcohol. The preparation method comprises the following steps: Step 1, polyurethane foam preparation: add dry polyether polyol to a reaction vessel, heat to 80°C and stir for 2 hours, add polyisocyanate, add catalyst, foam stabilizer and antibacterial alcohol 15 minutes before the end of stirring, stir evenly and pour into a mold, add foaming agent, stir at high speed for 5 seconds, and then stand for foaming molding, and the foaming time is 8 hours; the drying temperature of the dry polyether polyol is 110°C, the drying time is 2 hours, and the stirring speed is 1200 r / min; Step 2, preparation of a chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinker and a plasticizer, stirring evenly, adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution, wherein in the preparation of the chitosan-based adhesive layer, the stirring speed during the dissolution of chitosan is 500 r / min, and the stirring time is 2 h; the stirring time after adding the crosslinker and plasticizer is 45 min; and the stirring time after adding the antimicrobial alcohol is 20 min; Step 3, dressing assembly: evenly apply the chitosan-based adhesive layer solution on the surface of the release paper, controlling the thickness to 30 microns, cut it after drying and adhere it to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

[0026] The polyether polyol is a medium-chain polyol with a molecular weight of 2000; the polyisocyanate is isophorone diisocyanate. The catalyst is an organotin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft foam silicone oil or lauryl alcohol. The chitosan has a degree of deacetylation of 95% and a viscosity-average molecular weight of 300 kDa; the crosslinker is CS-01, a chitosan-specific crosslinker; and the plasticizer is sorbitol. The polyurethane foam layer has a density of 60 kg / m³, a tensile strength of 16 MPa, and an elongation at break of 300%. The chitosan-based adhesive layer has a peel strength of 0.06 MPa, an antibacterial rate of 98% against Escherichia coli, and an antibacterial effect of 98% on bacterial colonies. Figure 3 shown.

[0027] Example 4 An antibacterial polyurethane foam dressing has a multi-layer structure, an outer polyurethane foam layer, and an inner chitosan-based adhesive layer. The polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts polyether polyol, 45 parts polyisocyanate, 60 parts blowing agent, 0.3 parts catalyst, 0.15 parts foam stabilizer, and 0.5 parts antibacterial alcohol. The chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 75 parts chitosan, 250 parts deionized water, 7 parts cross-linking agent, 5 parts plasticizer, and 1.2 parts antibacterial alcohol. The antibacterial alcohol is a mixture of carveol and linalool. The preparation method comprises the following steps: Step 1, polyurethane foam preparation: dry polyether polyol is added to a reaction vessel, heated to 70°C and stirred for 1.5 hours, polyisocyanate is added, and 15 minutes before the end of stirring, a catalyst, foam stabilizer and antibacterial alcohol are added, stirred evenly and poured into a mold, a foaming agent is added, and high-speed stirring is performed for 4.5 seconds, and then allowed to stand for foaming and molding. The foaming time is 6 hours; wherein the drying temperature of the dry polyether polyol is 110°C, the drying time is 2 hours, and the stirring speed is 1200 r / min; Step 2, preparation of chitosan-based adhesive layer: chitosan is dissolved in deionized water, crosslinking agent and plasticizer are added, after stirring uniformly, antibacterial alcohol is added, continue to stir until completely dissolved, to obtain the adhesive layer solution, wherein the stirring speed of chitosan in the preparation of chitosan-based adhesive layer is 400r / min, the stirring time is 1.5h; the stirring time after adding crosslinking agent and plasticizer is 40min; the stirring time after adding antibacterial alcohol is 18min; Step 3, dressing assembly: the chitosan-based adhesive layer solution is uniformly coated on the surface of the release paper, the thickness is controlled to be 25 microns, after drying, cutting and adhering to the surface of the polyurethane foam layer, an antibacterial polyurethane foam dressing is obtained.

[0028] The above-mentioned polyether polyol is a medium-long chain type polyol with a molecular weight of 1500; the polyisocyanate is diphenylmethane diisocyanate. The catalyst is an organic tin catalyst; the foaming agent is distilled water; the foam stabilizer is soft silicone oil or lauryl alcohol. The degree of deacetylation of chitosan is 85%, and the viscosity-average molecular weight is 150kDa; the crosslinking agent is glutaraldehyde; the plasticizer is glycerol. The density of the polyurethane foam layer is 45kg / m³, the tensile strength is 1.4MPa, and the elongation at break is 270%; the peeling strength of the chitosan-based adhesive layer is 0.045MPa, and the antibacterial rate against escherichia coli is 96%.

[0029] Example 5 An antibacterial polyurethane foam dressing, which is a multilayer structure, the outer layer is a polyurethane foam layer, and the inner layer is a chitosan-based adhesive layer; the polyurethane foam layer is prepared by foaming process from the following components by weight: polyether polyol 100 parts, polyisocyanate 48 parts, foaming agent 65 parts, catalyst 0.35 parts, foam stabilizer 0.25 parts, and antibacterial alcohol 0.7 parts; the chitosan-based adhesive layer is prepared by dissolving and crosslinking from the following components by weight: chitosan 85 parts, deionized water 280 parts, crosslinking agent 9 parts, plasticizer 6 parts, and antibacterial alcohol 1.5 parts; wherein the antibacterial alcohol is a mixture of nerolidol and vetiverol, and the preparation method thereof comprises the following steps: Step 1, preparation of polyurethane foam: dry polyether polyol is added to the reaction container, heated to 75℃ and stirred for 1.8h, polyisocyanate is added, 15min before the end of stirring, catalyst, foam stabilizer and antibacterial alcohol are added, stirred uniformly, then poured into the mold, foaming agent is added, high-speed stirring for 4.8s, then static foaming and molding, foaming time is 7 hours; wherein the drying temperature of dry polyether polyol is 110℃, the drying time is 2h, and the stirring speed is 1200r / min; Step 2, preparation of a chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinker and a plasticizer, stirring evenly, adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution, wherein in the preparation of the chitosan-based adhesive layer, the stirring speed during the dissolution of chitosan is 450 r / min, and the stirring time is 1.8 h; the stirring time after adding the crosslinker and plasticizer is 42 min; and the stirring time after adding the antimicrobial alcohol is 19 min; Step 3, dressing assembly: evenly apply the chitosan-based adhesive layer solution on the surface of the release paper, controlling the thickness to 28 microns, cut it after drying and adhere it to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

[0030] The polyether polyol is a medium-chain polyol with a molecular weight of 1800; the polyisocyanate is isophorone diisocyanate. The catalyst is an organotin catalyst; the foaming agent is distilled water; and the foam stabilizer is lauryl alcohol. The chitosan has a degree of deacetylation of 90% and a viscosity-average molecular weight of 220 kDa. The crosslinker is CS-01; and the plasticizer is sorbitol. The polyurethane foam layer has a density of 55 kg / m³, a tensile strength of 1.55 MPa, and an elongation at break of 290%. The chitosan-based adhesive layer has a peel strength of 0.055 MPa and an antibacterial rate against Escherichia coli of 97%.

[0031] Control group: A polyurethane foam dressing having a multi-layer structure, an outer polyurethane foam layer, and an inner chitosan-based adhesive layer; the polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts of polyether polyol, 50 parts of polyisocyanate, 70 parts of foaming agent, 0.4 parts of catalyst, and 0.3 parts of foam stabilizer; the chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 100 parts of chitosan, 300 parts of deionized water, 10 parts of cross-linking agent, and 8 parts of plasticizer. The preparation method comprises the following steps: Step 1, polyurethane foam preparation: add dry polyether polyol to a reaction vessel, heat to 80°C and stir for 2 hours, add polyisocyanate, add catalyst and foam stabilizer 15 minutes before the end of stirring, stir evenly and pour into a mold, add foaming agent, stir at high speed for 5 seconds, and then stand for foaming molding, the foaming time is 8 hours; the drying temperature of the dry polyether polyol is 110°C, the drying time is 2 hours, and the stirring speed is 1200 r / min; Step 2, preparation of the chitosan-based adhesive layer: chitosan was dissolved in deionized water, crosslinking agent and plasticizer were added, and stirring was performed until complete dissolution to obtain an adhesive layer solution. In the preparation of the chitosan-based adhesive layer, the stirring speed during chitosan dissolution was 500 r / min, the stirring time was 2 h; the stirring time after adding the crosslinking agent and the plasticizer was 45 min; and the stirring time after adding the antibacterial alcohol was 20 min. Step 3, assembly of the dressing: the chitosan-based adhesive layer solution was uniformly coated on the surface of the release paper, the thickness was controlled to be 30 microns, and after drying, cutting and adhesion to the surface of the polyurethane foam layer, a polyurethane foam dressing was obtained.

[0032] The above-mentioned polyether polyol is a medium-long chain type polyol with a molecular weight of 2000; the polyisocyanate is isophorone diisocyanate. The catalyst is an organic tin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft silicone oil or lauryl alcohol. The degree of deacetylation of chitosan is 95%, and the viscosity-average molecular weight is 300 kDa; the crosslinking agent is a chitosan special crosslinking agent CS-01; and the plasticizer is sorbitol. The density of the polyurethane foam layer is 50 kg / m³, the tensile strength is 12 MPa, and the elongation at break is 200%; the peeling strength of the chitosan-based adhesive layer is 0.04 MPa, the antibacterial rate against Escherichia coli is 30%, and the antibacterial effect is shown in the bacterial colony as Figure 4 .

[0033] The above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those of ordinary skill in the art within the spirit and scope of the present application should also be within the protection scope of the present application.

Claims

1. An antibacterial polyurethane foam dressing, characterized in that: The dressing has a multi-layer structure, with an outer layer being a polyurethane foam layer and an inner layer being a chitosan-based adhesive layer. The polyurethane foam layer is prepared by a foaming process from the following components in parts by weight: 100 parts of polyether polyol, 40-50 parts of polyisocyanate, 50-70 parts of foaming agent, 0.2-0.4 parts of catalyst, 0.02-0.3 parts of foam stabilizer, and 0.1-0.9 parts of antimicrobial alcohol. The chitosan-based adhesive layer is prepared by dissolving and cross-linking the following components in parts by weight: 50-100 parts of chitosan, 200-300 parts of deionized water, 5-10 parts of cross-linking agent, 3-8 parts of plasticizer, and 0.5-2 parts of antimicrobial alcohol. The antimicrobial alcohol includes one or more of linalool, citronellol, nerolidol, carveol, dihydromyrcenol, vetiverol, and lauryl alcohol, and the purity of the antimicrobial alcohol is not less than 90%.

2. The antibacterial polyurethane foam dressing according to claim 1, characterized in that: The polyether polyol is a medium-chain polyol with a molecular weight of 500-2000; the polyisocyanate is toluene diisocyanate, diphenylmethane diisocyanate or isophorone diisocyanate.

3. The antibacterial polyurethane foam dressing according to claim 1, characterized in that: The catalyst is an organic tin catalyst; the foaming agent is distilled water; and the foam stabilizer is soft foam silicone oil or lauryl alcohol.

4. The antibacterial polyurethane foam dressing according to claim 1, characterized in that: The chitosan has a deacetylation degree of 75% to 95% and a viscosity-average molecular weight of 50 to 300 kDa; the crosslinking agent is one of glutaraldehyde and chitosan-specific crosslinking agent CS-01; and the plasticizer is one of glycerol and sorbitol.

5. The antibacterial polyurethane foam dressing according to claim 1, characterized in that: The polyurethane foam layer has a density of 30-60kg / m³, a tensile strength of not less than 1.2MPa, and an elongation at break of not less than 250%. The chitosan-based adhesive layer has a peel strength of 0.03-0.06MPa, and an antibacterial rate against Staphylococcus aureus and Escherichia coli of not less than 95%.

6. A method for preparing the antibacterial polyurethane foam dressing according to any one of claims 1 to 5, characterized in that The following steps are involved: Step 1. Preparation of polyurethane foam: Add dry polyether polyol to a reaction vessel, heat to 60-80°C and stir for 1-2 hours, add polyisocyanate, add catalyst, foam stabilizer and antibacterial alcohol 15 minutes before the end of stirring, stir evenly and pour into a mold, add foaming agent, stir at high speed for 4-5 seconds, and then let it stand for foaming and molding. The foaming time is 4-8 hours; Step 2, preparation of chitosan-based adhesive layer: dissolving chitosan in deionized water, adding a crosslinking agent and a plasticizer, stirring evenly, adding antimicrobial alcohol, and continuing to stir until completely dissolved to obtain an adhesive layer solution; Step 3: Dressing assembly: Evenly apply the chitosan-based adhesive layer solution to the surface of the release paper to a thickness of 20-30 microns. After drying, cut the solution and adhere it to the surface of the polyurethane foam layer to obtain the antibacterial polyurethane foam dressing.

7. The preparation method according to claim 6, characterized in that: In the preparation of the polyurethane foam, the drying temperature of the dried polyether polyol is 110° C., the drying time is 2 hours, and the stirring speed is 1200 r / min.

8. The preparation method according to claim 6, characterized in that: In the preparation of the chitosan-based adhesive layer, the stirring speed during chitosan dissolution is 300-500 r / min, and the stirring time is 1-2 hours; the stirring time after adding the crosslinking agent and plasticizer is 30-45 minutes; and the stirring time after adding the antibacterial alcohol is 15-20 minutes.

9. Use of the antibacterial polyurethane foam dressing according to any one of claims 1 to 5 in the preparation of medical dressings and wound care products.

10. Use of the antibacterial polyurethane foam dressing according to any one of claims 1 to 5 in the preparation of an Escherichia coli inhibition product.

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