Waterborne polyurethane slurry as well as preparation method and application thereof

Abstract

The invention provides waterborne polyurethane slurry as well as a preparation method and application thereof. The water-based polyurethane slurry comprises base resin, a foaming stabilizer, a filler, a water-based thickener, a water-based curing agent and an amine compound. The prepared water-based slurry is subjected to high-speed stirring and physical foaming to obtain foamed slurry, the slurry is coated on a base material, and the base material is dried under a high-temperature condition to obtain the breathable water-absorbing type water-based synthetic leather base.

Description

Technical Field

[0001] This invention relates to the field of waterborne synthetic leather technology, specifically to a waterborne polyurethane slurry, its preparation method, and its application. Background Technology

[0002] Recently, with the development of synthetic leather technology, synthetic leather products have gradually begun to replace premium products due to their high cost-effectiveness and lack of harm to animals. Today, people lead more diverse lives, which has led to more varied performance requirements for synthetic leather. These requirements are no longer limited to durability and feel, but rather to products with different performance characteristics that can be applied to various aspects of life.

[0003] A base fabric is coated with a layer of PU, resulting in a seamless, textureless surface after drying. Water-based synthetic leather differs significantly from solvent-based synthetic leather in its manufacturing process. Solvent-based synthetic leather's foam layer is formed through the exchange of water and solvent, while water-based leather is directly dried and formed. Therefore, water-based leather, due to the absence of solvent pollution during production, has become the trend. However, due to the different manufacturing processes, its performance characteristics also differ considerably. The exchange process in oil-based leather results in mostly open-cell foam layers, while directly dried water-based foam layers are mostly closed-cell. Consequently, water-based foam layers have lower air permeability than oil-based foam layers, significantly limiting their applications.

[0004] Patent CN201610375622.1 discloses a breathable synthetic leather and its preparation method. The synthetic leather prepared by this method has good breathability, but it uses a solvent-based preparation method. Furthermore, after the base material is made, its surface needs to be sanded to further open the pores on the base surface. This production process not only pollutes the environment with solvents, but also increases production costs and complicates the manufacturing process due to the added sanding process.

[0005] In view of the current situation where water-based synthetic leather base has poor air permeability and narrow application range, it is necessary to develop a new water-based polyurethane slurry and its preparation method to improve the application range and value of water-based synthetic leather base, thereby promoting the development of water-based synthetic leather and reducing oil pollution. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a water-based polyurethane slurry and its preparation method. The water-based synthetic leather base prepared by the water-based polyurethane slurry has excellent air permeability and, due to its open-cell effect, also has a certain degree of water absorption, which can effectively enhance the use value of water-based synthetic leather products.

[0007] The present invention also provides the application of the waterborne polyurethane slurry in the field of synthetic leather.

[0008] The present invention achieves the above-mentioned objectives through the following technical solutions:

[0009] In a first aspect, the present invention provides an aqueous polyurethane slurry comprising the following components in parts by weight:

[0010] The composition includes 100 parts base resin, 0.5-5 parts amine compounds, 0.3-2 parts water-based thickener, 0.3-2 parts water-based curing agent, 0-3 parts water-based color paste, 1-7 parts foaming and stabilizing agent, and 10-60 parts filler.

[0011] The base resin described in this invention is a foamable resin, preferably a polyether-type waterborne polyurethane resin, and more preferably has a solid content of 45-50 wt%.

[0012] The amine compounds described in this invention are amine compounds that can produce ammonia gas under heating conditions, such as ammonia water (preferably with a concentration of 5wt%-28wt%), urea, ammonium bicarbonate, etc., preferably, the heating conditions are 80-120℃;

[0013] The water-based thickener described in this invention is an associative polyurethane thickener or an alkali-swellable thickener, preferably an alkali-swellable thickener, such as an acrylic alkali-swellable thickener;

[0014] The water-based curing agent described in this invention is one or more of isocyanate curing agents, polycarbodiimide curing agents, and aziridine curing agents;

[0015] The water-based color paste described in this invention is a water-dispersible color paste;

[0016] The foaming and stabilizing agent described in this invention is a commonly used foam stabilizer in water-based synthetic leather, such as water-based foam stabilizers.

[0017] The filler described in this invention is a water-dispersible powder, such as one or more of hydrophilically modified heavy calcium carbonate, fiber powder, and light calcium carbonate.

[0018] In a second aspect of the present invention, the method for preparing the waterborne polyurethane slurry is as follows: a base resin, a foaming and stabilizing agent, a waterborne thickener, a waterborne curing agent, an amine compound, a filler, and an optional waterborne colorant are mixed evenly under the action of a disperser to obtain the waterborne polyurethane slurry.

[0019] In a third aspect, the present invention also provides the application of the waterborne polyurethane slurry in the field of waterborne synthetic leather.

[0020] In a specific embodiment, a method for preparing a breathable and water-absorbing water-based synthetic leather base is as follows:

[0021] S1: Foam the waterborne polyurethane slurry to obtain waterborne polyurethane foam slurry;

[0022] S2: Coat the substrate with water-based polyurethane foam slurry and dry it to obtain a breathable and water-absorbing water-based synthetic leather base.

[0023] Specifically, the foaming in S1 involves foaming the water-based polyurethane slurry under high-speed stirring, and the density after foaming is preferably 300-800 g / L.

[0024] Specifically, the coating thickness of the foaming slurry on the substrate in S2 is preferably 0.3-0.7 mm, and the drying temperature is 90-120℃.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In this application, amine compounds that generate ammonia gas at high temperatures are added to the formulation, causing ammonia gas to be generated and released from the inside of the bass during drying. This method opens the closed-cell cells in the bass, and under the action of high temperature and foam stabilizers, the cell structure is stabilized and will not collapse. After drying, the cell structure of the bass is fixed, resulting in an open-cell bass, which has better air permeability and water absorption. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to embodiments. It should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] Product performance testing methods:

[0029] The water absorption and air permeability of the sample were evaluated by testing the prepared bass with the standard ISO 811 for measuring static water pressure. The lower the water pressure value, the better the water absorption and air permeability.

[0030] Raw material source:

[0031] Foamed waterborne polyurethane 3483 (49wt% solids), 3472 (49wt% solids), Wanhua Chemical Co., Ltd., industrial product;

[0032] Alkali-swellable polyurethane thickener A801, Wanhua Chemical Co., Ltd., Industrial Product;

[0033] Water-based black paste, Shih Ming Co., Ltd., industrial product;

[0034] curing agent 166, Wanhua Chemical Co., Ltd., Industrial products;

[0035] Ammonia solution (25 wt%), Shanghai Aladdin Biochemical Technology Co., Ltd., analytical grade;

[0036] Foaming stabilizer EP-P-112, Evonik Industries, industrial products;

[0037] Urease, Shanghai Aladdin Biochemical Technology Co., Ltd., analytical grade;

[0038] Trihydrate, Kunjian Mineral Products Co., Ltd., industrial product.

[0039] Example 1

[0040] Preparation of waterborne polyurethane slurry:

[0041] Take 1000g of foamed polyurethane resin Add 3483, 60g foaming and stabilizing agent, 10g thickener, 10g water-based black paste, 10g curing agent, 20g ammonia, and 100g heavy calcium carbonate to a mixer and stir for 30 minutes until the paste is evenly dispersed.

[0042] Preparation of water-absorbing and breathable water-based synthetic leather base:

[0043] 1. The polyurethane slurry was foamed to a density of 600 g / L under high-speed dispersion.

[0044] 2. The water-based polyurethane foam slurry obtained in step 1 is coated onto the base fabric to a thickness of 0.5 mm;

[0045] 3. Place it in a 100℃ oven for drying to obtain breathable and water-absorbing water-based synthetic leather base 1.

[0046] Example 2

[0047] Preparation of waterborne polyurethane slurry:

[0048] Take 1000g of foamed polyurethane resin Add 3472, 30g foaming and stabilizing agent, 10g thickener, 10g water-based black paste, 10g curing agent, 50g urea, and 100g heavy calcium carbonate to a mixer and stir for 30 minutes until the slurry is evenly dispersed.

[0049] Preparation of water-absorbing and breathable water-based synthetic leather base:

[0050] 1. The polyurethane slurry was foamed to a density of 600 g / L under high-speed dispersion.

[0051] 2. The water-based polyurethane foam slurry obtained in step 1 is coated onto the base fabric to a thickness of 0.5 mm;

[0052] 3. Place it in a 100℃ oven for drying to obtain breathable and water-absorbing water-based synthetic leather base 2.

[0053] Example 3

[0054] Preparation of waterborne polyurethane slurry:

[0055] Take 1000g of foamed polyurethane resin Add 3472, 40g foaming and stabilizing agent, 9g thickener, 5g curing agent, 50g urea, and 150g heavy calcium carbonate to a mixer and stir for 30 minutes until the slurry is evenly dispersed.

[0056] Preparation of water-absorbing and breathable water-based synthetic leather base:

[0057] 1. The polyurethane slurry is foamed to a density of 500 g / L under high-speed dispersion;

[0058] 2. The water-based polyurethane foam slurry obtained in step 1 is coated onto the base fabric to a thickness of 0.6 mm;

[0059] 3. Place it in a 100℃ oven for drying to obtain breathable and water-absorbing water-based synthetic leather base 3.

[0060] Example 4

[0061] Preparation of waterborne polyurethane slurry:

[0062] Take 1000g of foamed polyurethane resin Add 3483, 50g foaming and stabilizing agent, 8g thickener, 20g water-based black paste, 15g curing agent, 50g urea, and 300g heavy calcium carbonate to a mixer and stir for 30 minutes until the paste is evenly dispersed.

[0063] Preparation of water-absorbing and breathable water-based synthetic leather base:

[0064] 1. The polyurethane slurry was foamed to a density of 400 g / L under high-speed dispersion.

[0065] 2. The water-based polyurethane foam slurry obtained in step 1 is coated onto the base fabric to a thickness of 0.7 mm;

[0066] 3. Place it in a 100℃ oven for drying to obtain breathable and water-absorbing water-based synthetic leather base.

[0067] Comparative Example 1

[0068] Preparation of waterborne polyurethane slurry:

[0069] Take 1000g of foamed polyurethane resin Add 3483, 60g foaming and stabilizing agent, 10g thickener, 10g water-based black paste, 10g curing agent, and 100g heavy calcium carbonate to a mixer and stir for 30 minutes until the slurry is evenly dispersed.

[0070] Preparation of water-based synthetic leather base:

[0071] 1. The polyurethane slurry was foamed to a density of 600 g / L under high-speed dispersion.

[0072] 2. The water-based polyurethane foam slurry obtained in step 1 is coated onto the base fabric to a thickness of 0.5 mm;

[0073] 3. Place it in a 100℃ oven for drying to obtain breathable and water-absorbing water-based synthetic leather base 5.

[0074] Comparative Example 2

[0075] Preparation of waterborne polyurethane slurry:

[0076] Take 1000g of foamed polyurethane resin Add 3472, 30g foaming stabilizer, 10g thickener, 10g water-based black paste, 10g curing agent, and 100g heavy calcium carbonate to a mixer and stir for 30 minutes until the slurry is evenly dispersed.

[0077] Preparation of water-based synthetic leather base:

[0078] 1. The polyurethane slurry is foamed to a density of 600 g / L under high-speed dispersion.

[0079] 2. Coat the base fabric with the water-based polyurethane foam slurry obtained in step 1, with a thickness of 0.5 mm;

[0080] 3. Place it in a 100℃ oven for drying to obtain breathable and water-absorbing water-based synthetic leather base 6.

[0081] The performance of the water-based synthetic leather backsheet samples prepared in the examples and comparative examples was tested according to the standard test method ISO 811-2018. The breathable water-based backsheets mostly have an open-cell structure, which provides channels for water to pass through. The easier it is for water to wet and penetrate the backsheet, and the lower the water pressure, the better the breathability of the backsheet.

[0082] The table below shows the performance test results.

[0083]

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A water-based polyurethane slurry, characterized in that, The components include the following parts by weight: The composition includes 100 parts base resin, 0.5-5 parts amine compounds, 0.3-2 parts water-based thickener, 0.3-2 parts water-based curing agent, 0-3 parts water-based color paste, 1-7 parts foaming and stabilizing agent, and 10-60 parts filler.

2. The waterborne polyurethane slurry according to claim 1, characterized in that, The base resin is a foamable resin, preferably a polyether-type waterborne polyurethane resin, and more preferably a solid content of 45-50 wt%.

3. The waterborne polyurethane slurry according to claim 1, characterized in that, The amine compound is one or more of ammonia, urea, and ammonium bicarbonate; preferably, the concentration of ammonia is 5-28 wt%.

4. The waterborne polyurethane slurry according to claim 1, characterized in that, The aqueous thickener is an associative polyurethane thickener or an alkali-swellable thickener, preferably an alkali-swellable thickener.

5. The waterborne polyurethane slurry according to claim 1, characterized in that, The water-based curing agent is one or more of isocyanate curing agents, polycarbodiimide curing agents, and aziridine curing agents.

6. The waterborne polyurethane slurry according to claim 1, characterized in that, The filler is a water-dispersible powder, preferably one or more of heavy calcium carbonate, fiber powder, and light calcium carbonate.

7. A method for preparing the waterborne polyurethane slurry according to any one of claims 1-6, characterized in that, The preparation method is as follows: the base resin, foaming stabilizer, water-based thickener, water-based curing agent, amine compound, filler and optional water-based color paste are mixed evenly to obtain water-based polyurethane slurry.

8. The application of the waterborne polyurethane slurry according to any one of claims 1-6 or the waterborne polyurethane slurry prepared by the preparation method according to claim 7, for use in the field of synthetic leather.

9. A method for preparing a breathable and absorbent water-based synthetic leather base is as follows: S1: Foam the waterborne polyurethane slurry to obtain waterborne polyurethane foam slurry; S2: Apply water-based polyurethane foam slurry to the substrate and dry it to obtain a breathable and water-absorbing water-based synthetic leather base.

10. The preparation method according to claim 9, characterized in that, The density after foaming in step S1 is 300-800 g / L; and / or the slurry coating thickness in step S2 is 0.3-0.7 mm; and / or the drying temperature in step S2 is 90-120℃.

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