A bio-based antibacterial fireproof polyurethane synthetic leather as well as a preparation method and application thereof

Abstract

The application discloses a kind of bio-based antibacterial fireproof polyurethane synthetic leather and its preparation method and application, the polyurethane synthetic leather, from top to bottom, includes bio-based polyurethane surface layer, bio-based polyurethane bonding layer and substrate layer, wherein: polyurethane surface layer includes tea extract, lignocellulose and other components, polyurethane bonding layer includes phytic acid modified isocyanate prepolymer, lignocellulose and other components.The application uses tea polyphenols in tea extract as antibacterial components and antioxidant components, and forms crosslinking structure with curing agent in surface layer resin at the same time, improves the combination of polyurethane coating, and further improves the color fastness and durability of product;Lignocellulose and other components act as carbon structure and phytic acid modified polyurethane bonding layer to improve the flame retardant performance of product.The application uses bio-based materials reasonably, and obtains bio-based antibacterial fireproof polyurethane synthetic leather with good durability.

Description

A bio-based antibacterial and fire-retardant polyurethane synthetic leather, its preparation method and application Technical Field

[0001] This invention relates to a preparation process of a functional polyurethane composite material, specifically to a bio-based antibacterial and fire-retardant polyurethane synthetic leather, its preparation method, and its application, belonging to the field of polyurethane synthetic leather technology. Background Technology

[0002] Bio-based materials are characterized by being green, environmentally friendly, and resource-saving, making them a key focus of my country's strategic emerging industries. Bio-based polyurethane synthetic leather, as an important new type of flexible bio-based composite material, has excellent application and development prospects.

[0003] With increasing public awareness of environmental protection, bio-based polyurethane synthetic leather is gradually expanding its application in fields such as sports and leisure footwear, sofas and furniture, sporting goods, electronic packaging, interior and engineering decoration, and automotive interiors. However, in engineering decoration, automotive interiors, and public places, where high flame-retardant performance is required, polyurethane materials, like traditional polymers, are prone to combustion, posing a fire hazard. Therefore, flame-retardant treatment is necessary for polyurethane materials used in these applications. Furthermore, with growing emphasis on healthy living, antibacterial properties have become a crucial requirement for polyurethane synthetic leather.

[0004] Due to the poor bonding between existing bio-based polyurethane resins, bio-based fillers, various functional additives, and bio-based fabrics, the functionalization of bio-based polyurethane synthetic leather is limited. How to improve the dispersibility of bio-based flame retardants and bio-based antibacterial additives in bio-based polyurethane resins so that they can play their due role is a difficult problem. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a bio-based antibacterial and fire-retardant polyurethane synthetic leather, its preparation method, and its application. This invention employs a bio-based antibacterial and fire-retardant process, and the antibacterial agent and flame retardant used are both bio-based materials, resulting in a bio-based, durable, antibacterial, and fire-retardant polyurethane synthetic leather material.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] The first aspect of the present invention is to provide a bio-based antibacterial and fire-retardant polyurethane synthetic leather, comprising, from top to bottom, a bio-based polyurethane surface layer, a bio-based polyurethane adhesive layer, and a substrate layer, wherein:

[0008] The polyurethane surface layer is prepared from a polyurethane surface layer slurry composed of the following components in parts by weight: 100 parts bio-based polyurethane resin, 2-5 parts tea extract, 2-4 parts wear-resistant additive, 10-15 parts lignocellulose, 2-3 parts curing agent, and 1-5 parts color paste; more preferably, the bio-based polyurethane resin is at least one of polypropylene carbonate type polyurethane, polylactic acid type polyurethane, bio-based polyether type polyurethane, or bio-based polycarbonate type polyurethane; the tea extract refers to a substance extracted from tea leaves or tea residue, the main component of which is tea polyphenols; the tea leaves are one or more of white tea, green tea, and black tea; the curing agent is an isocyanate curing agent, preferably an HDI trimer.

[0009] The polyurethane adhesive layer is prepared from a solvent-free polyurethane adhesive layer slurry composed of the following components in parts by weight: 100 parts of carbon dioxide-based polyol, 50-70 parts of phytic acid-modified isocyanate prepolymer, 10-60 parts of lignocellulose, 0.15-0.2 parts of organometallic catalyst, and 0.3-0.4 parts of amine catalyst; more preferably, the carbon dioxide-based polyol is polypropylene carbonate diol; the preparation method of the phytic acid-modified isocyanate prepolymer is as follows: phytic acid reacts with an excess of diamine (the amount of diamine is about 3.1-3.5 times that of phytic acid) at 100°C to form a terminal amine structure, and then reacts with an excess of diphenylmethane diisocyanate at 30-50°C to finally form the phytic acid-modified isocyanate prepolymer. The reaction principle is as follows: Phytic acid is an organic acid containing multiple hydroxyl groups, which can undergo acid-base neutralization reaction with diamine. Under the action of excess diamine, it forms terminal amine compounds, which then react with isocyanate to form phytic acid-modified isocyanate prepolymer.

[0010] The lignocellulose in the aforementioned polyurethane surface layer or polyurethane adhesive layer originates from wood waste or cottonseed hulls generated during wood processing, with no limit on the proportion. Lignocellulose contains a large number of hydroxyl groups, which, when added to polyurethane, can form hydrogen bonds with the polyurethane and can also crosslink with the isocyanate curing agent in the polyurethane. These effects can increase the bonding between the various layers of polyurethane; at the same time, lignocellulose can act as a carbon skeleton, increasing the flame retardant properties of the product.

[0011] A second aspect of the present invention is to provide a method for preparing bio-based antibacterial and fire-retardant polyurethane synthetic leather as described in one aspect, comprising the following steps:

[0012] Step 1: Coat the release paper with a bio-based polyurethane surface layer slurry to a thickness of 0.2-0.25 mm, and dry to form a bio-based polyurethane surface layer; preferably, the drying temperature is 115-125℃ and the drying time is 2.5-5 min.

[0013] Step 2: Apply a solvent-free polyurethane adhesive layer slurry to the bio-based polyurethane surface layer with a thickness of 0.2-0.3 mm. Pre-react at 120-130℃ for 2-3 minutes to form a semi-dry polyurethane adhesive layer with certain adhesion.

[0014] Step 3: Plug the phytic acid-treated base fabric onto the polyurethane adhesive layer, and after drying and peeling off the release paper, the final product is obtained; the drying temperature is 130-140℃ and the drying time is 2-3 minutes.

[0015] A third aspect of the invention is to provide the application of bio-based antimicrobial and fire-retardant polyurethane synthetic leather as described in the first aspect, which can be used in fields such as engineering decoration, automotive products, or medical beds.

[0016] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0017] This invention adds bio-based lignocellulose to the polyurethane surface layer and adhesive layer as a char-forming component, and uses phytic acid-modified isocyanate prepolymer in the solvent-free polyurethane adhesive layer slurry. Since phytic acid contains phosphorus, it has certain flame retardant properties. This invention utilizes lignocellulose as a char-forming skeleton, which works synergistically with phosphorus-containing bio-based phytic acid to significantly improve the flame retardant performance of the product and expand the application range of bio-based materials.

[0018] This invention incorporates tea extract into the polyurethane surface layer. On the one hand, the main component of tea extract, tea polyphenols, can improve the antibacterial properties of the product. On the other hand, tea polyphenols can work together with phytic acid to play an antioxidant role. At the same time, it forms a cross-linked network structure with the bio-based curing agent, which improves its binding with the resin, thereby improving the color fastness and durability of the product.

[0019] The product obtained by this invention has a bio-based content of up to 50%, which not only meets the increasingly stringent environmental protection requirements of branded home furnishings and engineering decoration, but also greatly improves the antibacterial and flame-retardant properties of bio-based polyurethane synthetic leather, thus significantly enhancing the product's durability and extending its service life. The product meets the 5-year hydrolysis resistance requirement (70℃*95%RH*5W, leather surface does not crack or powder); antibacterial grade I, antibacterial rate ≥99%; QUV 340nm300H yellowing resistance grade 4; flame retardancy grade passing the British Standard BS-5852 No. 1 ignition source and GB 8410 automotive interior flame retardancy test; dry and wet rubbing color fastness ≥500 times grade 4; peel strength ≥30N / 3cm. Detailed Implementation

[0020] The present invention will be further described below with reference to embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0021] In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional methods in the prior art, and therefore will not be described in detail; the parts in the following embodiments refer to parts by mass.

[0022] The product / equipment models and manufacturers used in the following embodiments are as follows:

[0023] The raw material information used in the following examples is as follows:

[0024] The bio-based surface resin was supplied by Hefei Anli Polyurethane New Materials Co., Ltd., with the brand name [Brand Name Missing]. CQ DL1878;

[0025] The tea extract is a green tea extract from Nanjing Spaco Biochemical Industry Co., Ltd.

[0026] The manufacturer of the wear-resistant additive is Zhongshan Meiliken, and the brand name is BNK-NSF898.

[0027] The curing agent is HDI trimer, brand name Yantai Wanhua WANNATE HT-100;

[0028] The color paste manufacturer is Jiangxi Sanyue Chemical PU dry process color paste;

[0029] The lignocellulose was sourced from Yixing Shengdeli and is white lignocellulose from Yixing Shengdeli.

[0030] The carbon dioxide-based polyol was synthesized according to the process in Example 2 of the patent titled "Carbon Dioxide-Based Polyol, Its Preparation Method and Application" and patent number CN202010440750.6;

[0031] Phytic acid was purchased from Shaanxi Chenming Biotechnology Co., Ltd.

[0032] The isocyanate prepolymer is a polyester-type MDI prepolymer, manufactured by BASF Polyurethanes (China) Co., Ltd., with the brand name HAPTEX CC 6945 / 1505C-B.

[0033] The diamine was triethylenediamine, which was purchased from Shandong Hongyunchang Chemical Technology Co., Ltd.

[0034] Diphenylmethane diisocyanate (MDI) was purchased from Wanhua Chemical.

[0035] The organometallic catalyst used is an organobismuth catalyst, manufactured by Deyin Chemical, with the brand name DY-20.

[0036] The amine catalyst used is a tertiary amine catalyst, manufactured by BASF Polyurethanes (China) Co., Ltd., with the brand name CX 93600;

[0037] Antioxidant 1010 and Antioxidant 168 in Comparative Example 3 were purchased from Ciba Specialty Chemicals.

[0038] The nano-antibacterial agent in Comparative Example 2 is Andyme SR-5 antibacterial and antifungal agent, manufactured by Beijing Chonggao Nanotechnology Co., Ltd.

[0039] The reagents described above are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to provide full disclosure, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0040] The phytic acid-modified isocyanate prepolymers used in the following examples were obtained through the following preparation method:

[0041] Phytic acid reacts with an excess of diamine (the amount of diamine is about 3.3 times that of phytic acid) at 100°C to form a terminal amine structure. It then reacts with an excess of diphenylmethane diisocyanate at 40°C to finally form a phytic acid-modified isocyanate prepolymer.

[0042] Example 1

[0043] A method for preparing a bio-based antibacterial and fire-retardant polyurethane synthetic leather includes the following steps:

[0044] Step 1: Coat the release paper with a polyurethane surface layer slurry. The specific composition of the polyurethane surface layer slurry is as follows: 100 parts AL-8070 resin, 2 parts green tea extract, 4 parts Changhui BNK-NSF898 abrasion-resistant additive, 10 parts lignocellulose, 2 parts Wanhua WANNATE HT-100, and 5 parts Mitsukoshi black paste; the coating thickness is 0.2 mm, and it is dried at 115℃ for 5 minutes to form a polyurethane surface layer.

[0045] Step 2: Apply a layer of flame-retardant, solvent-free polyurethane adhesive slurry to the polyurethane surface layer. The specific composition of the adhesive slurry is as follows: 100 parts carbon dioxide-based polyol A, 50 parts phytic acid-modified isocyanate prepolymer, 10 parts lignocellulose, 0.15 parts Deyin Chemical DY-20 organic bismuth catalyst, and 0.3 parts BASF CX 93600 catalyst. The coating thickness is 0.2 mm. After pre-reaction at 120℃ for 3 minutes, a semi-dry polyurethane adhesive layer is formed, which has certain adhesion.

[0046] Step 3: The drying temperature of the phytic acid-treated base fabric bonded to the adhesive layer is 130℃, and the drying time is 3 minutes. After peeling off the release paper, the polyurethane synthetic leather product is obtained. The preparation method of the phytic acid-treated base fabric is as follows: 100% polyester base fabric is immersed in a 20% phytic acid aqueous solution, and then rolled dry and dried to obtain the product (the method of phytic acid-treated base fabric in other embodiments below is the same as in Example 1).

[0047] Example 2

[0048] A method for preparing a bio-based antibacterial and fire-retardant polyurethane synthetic leather includes the following steps:

[0049] Step 1: Coat the release paper with a polyurethane surface layer. The specific composition of the polyurethane surface layer slurry is as follows: 100 parts AL-8070 resin, 5 parts green tea extract, 4 parts Changhui BNK-NSF898 abrasion-resistant additive, 15 parts lignocellulose, 3 parts Wanhua WANNATE HT-100, and 5 parts Mitsukoshi black paste; the coating thickness is 0.25 mm, and it is dried at 125℃ for 2.5 min to form the polyurethane surface layer.

[0050] Step 2: Apply a layer of flame-retardant, solvent-free polyurethane adhesive slurry to the polyurethane surface layer. The specific composition of the adhesive slurry is as follows: 100 parts carbon dioxide-based polyol A, 70 parts phytic acid-modified isocyanate prepolymer, 60 parts lignocellulose, 0.2 parts Deyin Chemical DY-20 organic bismuth catalyst, and 0.4 parts BASF CX 93600 catalyst. The coating thickness is 0.2 mm. After pre-reaction at 130℃ for 2 minutes, a semi-dry polyurethane adhesive layer is formed, which has certain adhesion.

[0051] Step 3: The drying temperature of the phytic acid-treated base fabric bonded to the adhesive layer is 140℃, and the drying time is 2 minutes. After peeling off the release paper, the polyurethane synthetic leather product is obtained.

[0052] Example 3

[0053] A method for preparing a bio-based antibacterial and fire-retardant polyurethane synthetic leather includes the following steps:

[0054] Step 1: Coat the release paper with a polyurethane surface layer. The specific composition of the polyurethane surface layer slurry is as follows: 100 parts AL-8070 resin, 3 parts green tea extract, 4 parts Changhui BNK-NSF898 abrasion-resistant additive, 12 parts lignocellulose, 2.5 parts Wanhua WANNATE HT-100, and 5 parts Mitsukoshi black paste; the coating thickness is 0.25 mm, and it is dried at 125℃ for 2.5 min to form the polyurethane surface layer.

[0055] Step 2: Apply a layer of flame-retardant, solvent-free polyurethane adhesive slurry to the polyurethane surface layer. The specific composition of the adhesive slurry is as follows: 100 parts carbon dioxide-based polyol A, 60 parts phytic acid-modified isocyanate prepolymer, 30 parts lignocellulose, 0.2 parts Deyin Chemical DY-20 organic bismuth catalyst, and 0.4 parts BASF CX 93600 catalyst. The coating thickness is 0.2 mm. After pre-reaction at 130℃ for 2 minutes, a semi-dry polyurethane adhesive layer is formed, which has a certain degree of adhesion.

[0056] Step 3: The drying temperature of the phytic acid-treated base fabric bonded to the adhesive layer is 140℃, and the drying time is 2 minutes. After peeling off the release paper, the polyurethane synthetic leather product is obtained.

[0057] Comparative Example 1

[0058] Compared with Example 1, the only difference in Comparative Example 1 is that "green tea extract" is not added in step 1, while the other processes are the same as in Example 1.

[0059] Comparative Example 2

[0060] The difference between Comparative Example 2 and Example 1 is that in step 1, "green tea extract" is not added, but two parts of nano antibacterial agent are added instead. All other processes are the same as in Example 1.

[0061] Comparative Example 3

[0062] Compared with Example 1, the only difference in Comparative Example 3 is that "green tea extract" is not added in step 1, but instead 1 part antioxidant 1010 and 1 part antioxidant 168 are added. All other processes are the same as in Example 1.

[0063] Comparative Example 4

[0064] The difference between Comparison 4 and Example 1 is that no curing agent is added in step 1, while the other processes are consistent with Example 1.

[0065] Comparative Example 5

[0066] Compared with Example 2, Comparative Example 5 differs only in that lignocellulose is not added in steps 1 and b, but the same amount of aluminum hydroxide is added instead. All other processes are consistent with Example 2.

[0067] Comparative Example 6

[0068] Compared with Example 2, the only difference in Comparative Example 6 is that the phytic acid modified isocyanate prepolymer was replaced with a regular isocyanate prepolymer in step 2. All other processes were the same as in Example 2.

[0069] The performance of the products prepared in the above embodiments and comparative examples was tested, and the results are shown in Table 1 below:

[0070] Table 1. Performance test results of products obtained from each embodiment and comparative example.

[0071]

[0072] Remark:

[0073] The test method for bio-based content is ASTM D6866;

[0074] The antimicrobial rate test method is ISO 22196-2011;

[0075] The grayscale level testing method is Method A in QB / T 4672-2014;

[0076] The test method for horizontal combustion rate is GB 8410, and the test result represents the combustion rate;

[0077] The comparison between Example 1 and Comparative Examples 1 and 2 in Table 1 shows that tea extract provides effective antibacterial effects. The comparison between Example 1 and Comparative Examples 2, 3, and 4 shows that tea extract can prevent yellowing. The comparison between Example 2 and Comparative Examples 6 shows that lignocellulose and phytic acid-modified prepolymers have a significant impact on flame retardant effects. The comprehensive test results indicate that this invention, through the comprehensive utilization of bio-based materials such as tea extract, lignocellulose, and phytic acid, improves the biomass content and flame retardant properties of the materials, while ensuring product durability, thus replacing the role of nano-antibacterial agents and anti-yellowing additives and enhancing the product's antibacterial and anti-yellowing capabilities. This is because lignocellulose can act as a carbon skeleton, synergistically interacting with phosphorus-containing bio-based phytic acid to increase the flame retardant properties of the product; while tea extract contains a large amount of tea polyphenols, which have antibacterial and antioxidant effects, increasing the antibacterial and anti-yellowing properties of the product; in addition, lignocellulose, phytic acid and tea extract all contain a large number of hydroxyl structures, which can form hydrogen bonds with polyurethane resin and react with isocyanates in curing agents to form cross-linked structures, ensuring the durability of the product.

[0078] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A bio-based antibacterial and fire-retardant polyurethane synthetic leather, characterized in that, From top to bottom, the structure comprises a bio-based polyurethane top layer, a bio-based polyurethane adhesive layer, and a substrate layer. The polyurethane top layer is prepared from a polyurethane top layer slurry composed of the following components: bio-based polyurethane resin, tea extract, lignocellulose, wear-resistant additives, curing agent, and colorant. The polyurethane adhesive layer is prepared from a solvent-free polyurethane adhesive layer slurry composed of the following components: carbon dioxide-based polyol, phytic acid-modified isocyanate prepolymer, lignocellulose, and catalyst. The tea extract refers to a substance extracted from tea leaves, with tea polyphenols as its main component. The mass percentages of each component in the polyurethane top layer slurry are as follows: 100 parts bio-based polyurethane resin. The phytic acid-modified isocyanate prepolymer is prepared by reacting phytic acid with excess diamine to form a terminal amine structure, and then reacting with excess diphenylmethane diisocyanate to form a phytic acid-modified isocyanate prepolymer. The solvent-free polyurethane adhesive slurry contains the following components in the following mass percentages: 100 parts carbon dioxide-based polyol, 50-70 parts phytic acid-modified isocyanate prepolymer, 10-60 parts lignocellulose, 0.15-0.2 parts organometallic catalyst, and 0.3-0.4 parts amine catalyst.

2. The bio-based antibacterial and fire-retardant polyurethane synthetic leather according to claim 1, characterized in that, The bio-based polyurethane resin is at least one of polypropylene carbonate type polyurethane, polylactic acid type polyurethane, bio-based polyether type polyurethane, or bio-based polycarbonate type polyurethane.

3. The bio-based antibacterial and fire-retardant polyurethane synthetic leather according to claim 1, characterized in that, The tea residue is one or more of white tea, green tea, and black tea.

4. The bio-based antibacterial and fire-retardant polyurethane synthetic leather according to claim 1, characterized in that, The curing agent is an isocyanate curing agent.

5. The bio-based antibacterial and fire-retardant polyurethane synthetic leather according to claim 1, characterized in that, The carbon dioxide-based polyol is polypropylene carbonate diol; the catalyst includes organometallic catalysts and amine catalysts.

6. The method for preparing bio-based antibacterial and fire-retardant polyurethane synthetic leather according to any one of claims 1 to 5, characterized in that, The process includes the following steps: coating a bio-based polyurethane surface layer slurry onto release paper with a thickness of 0.2-0.25 mm, followed by drying to form a bio-based polyurethane surface layer; the drying temperature is 115-125℃, and the drying time is 2.5-5 min; coating a solvent-free polyurethane adhesive layer slurry onto the bio-based polyurethane surface layer with a thickness of 0.2-0.3 mm, and pre-reacting at 120-130℃ for 2-3 min to form a semi-dry polyurethane adhesive layer; bonding a phytic acid-treated base fabric onto the polyurethane adhesive layer, and after drying and peeling off the release paper, the final product is obtained; the drying temperature is 130-140℃, and the drying time is 2-3 min.

7. The application of bio-based antibacterial and fire-retardant polyurethane synthetic leather as described in any one of claims 1 to 5, characterized in that, The bio-based antibacterial and fire-retardant polyurethane synthetic leather is used in engineering decoration, automotive products, or medical beds.

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