Cool PU (polyurethane) and preparation method thereof

Abstract

The invention discloses cool PU (polyurethane), which relates to the field of artificial leather and sequentially comprises a coating layer, a PU surface layer, a PU foaming layer and a base cloth layer from top to bottom. According to the invention, the high infrared reflection characteristic of the mica powder on infrared rays directly irradiated by sunlight is exerted, the absorption of the product on heat radiation is greatly reduced, and the octadecane microsphere powder added in the system controls the temperature by utilizing the phase change (liquid-solid conversion) characteristic of the octadecane microsphere powder, so that the PU has an intelligent temperature regulation function and has a better cool feeling.

Description

Technical Field

[0001] The present invention relates to the field of artificial leather, in particular to a cool feeling PU and a preparation method thereof. Background Art

[0002] In the automotive interior sector, traditional polyurethane (PU) materials have significant drawbacks when used for seat coverings. When a car is parked outdoors in the sun, the surface temperature of seats made of traditional PU material rises rapidly, causing significant discomfort for the driver and passengers. This is primarily due to the low infrared reflectivity of traditional PU materials, which cannot effectively reflect infrared rays from sunlight, resulting in the absorption of a large amount of thermal radiation. Furthermore, traditional PU materials have poor air permeability, making it difficult for heat to dissipate in high-temperature environments, further exacerbating the stuffy feeling on the seat surface.

[0003] Currently, cooling PU products have some applications in the clothing sector, but their application in automotive interiors is quite limited. Automotive interiors place stringent demands on material durability, fastness, and other performance indicators. Existing cooling PU materials suitable for clothing cannot be directly applied to car seat coverings. Therefore, developing a cooling PU material and its preparation method that can meet the requirements of automotive interior coverings while maintaining a low surface temperature in high-temperature environments is of great practical significance. Summary of the Invention

[0004] To achieve the above object, the present invention provides the following technical solution: a cool feeling PU, characterized in that it comprises, from top to bottom, a coating layer, a PU surface layer, a PU foam layer, and a base fabric layer;

[0005] The raw materials of the finishing layer include the following components in parts by weight: 40-60 parts of semi-bright matte surface treatment agent, 45-60 parts of matte surface treatment agent, 8-16 parts of hand feeling and wear resistance agent, 0.2-0.3 parts of defoaming agent, 0.2-0.3 parts of antibacterial agent, 0.8-1 parts of leveling agent, 5-7 parts of cross-linking agent, 5-10 parts of mica powder, and 25-40 parts of industrial distilled water;

[0006] The raw materials of the PU surface layer include the following components in parts by weight: 95-105 parts of PU resin, 60-65 parts of DMF, 10-15 parts of ethyl acetate, and 25-40 parts of color paste;

[0007] The PU foam layer comprises the following components in parts by weight: 95-105 parts of PU resin, 60-65 parts of DMF, 19-25 parts of ethyl acetate, 25-40 parts of color paste, 95-105 parts of solvent-free adhesive material A, 48-70 parts of solvent-free adhesive material B, 1-3 parts of octadecane microspheres, 0.04-0.06 parts of accelerator, 0.18-0.3 parts of curing agent, 0.15-0.25 parts of leveling agent, and 35-50 parts of flame retardant.

[0008] Preferably, the solvent-free adhesive material A is isocyanate, and the solvent-free adhesive material B is polyol.

[0009] Preferably, the base fabric layer is a bamboo fiber base fabric.

[0010] The preparation steps of the above materials are as follows:

[0011] S1: Preparation of PU surface layer: DMF, ethyl acetate, and color paste were added to the PU resin according to the weight ratio of the formula, and the mixture was stirred to obtain a PU mixture. The PU mixture was applied to the release paper with a coating thickness of 0.15±0.01mm and a speed of 11±1m / min. The temperature was increased in a stepwise manner to 70 / 80 / 100 / 110 / 125 / 125°C for a total of 4 minutes. Each temperature was set for the same time period to obtain the PU surface layer.

[0012] S2: Adding PU foam layer: According to the weight ratio of the formula, the raw materials of the PU foam layer are mixed evenly and applied to the surface of the PU surface layer. The coating thickness is 0.25±0.01mm. The vehicle speed is controlled at 10±1m / min. The temperature is stepped and heated and dried at 100 / 100 / 100 / 110 / 125 / 125℃ in sequence. The drying time is 15min in total. Each temperature is set for the same time period to obtain the PU foam layer.

[0013] S3: Adding base fabric layer: Lay one side of the PU foam layer on the base fabric, and heat and dry it in a step-by-step manner at the following temperatures: 135 / 135 / 135 / 140 / 140 / 140 / 140 / 140 / 145 / 145 / 145 / 145 / 145°C, drying time 12 min, with the same time period set for each temperature. Then, separate the release paper, curl it, and make a PU semi-finished product, with the separated release paper side having the PU texture surface;

[0014] S4: Finishing layer: Mix the raw materials of the aqueous treatment layer evenly according to the weight ratio of the formula, and then use a roller coater to apply it to the PU surface layer side of the PU semi-finished product. The speed is controlled at 10±2m / min, and the temperature is stepped and heated and dried. The drying temperatures are 125 / 130 / 130 / 130 / 130 / 130℃ in sequence, and the drying time is 2-3min. Each temperature is set for the same time period, and curled after drying.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In the past, cool PU products were only available in clothing applications. The key to this invention is the use of an isocyanate / polyol solvent-free adhesive that is water-free and contains mica powder and octadecane microsphere powder.

[0017] In terms of the product's structural and functional design, the front is coated with a water-based coating containing mica powder. This design leverages the mica powder's high infrared reflectivity against direct sunlight, significantly reducing the product's absorption of thermal radiation. Furthermore, the addition of octadecane microsphere powder to the system utilizes its phase change (liquid-solid transition) properties to control temperature, giving the PU intelligent thermostatting capabilities and a superior cooling effect.

[0018] The back of the product is made of a bamboo fiber base fabric with excellent breathability and thermal conductivity. This choice of base fabric further enhances the product's heat dissipation capacity, ensuring that the PU finished product can maintain a low temperature even after exposure to the sun, providing a cool touch experience for users. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the product structure of the present invention;

[0020] Figure 2 is a reflectivity curve diagram of Example 1 of the present invention;

[0021] Figure 3 is a reflectivity curve diagram of Example 2 of the present invention;

[0022] Figure 4 This is the emissivity curve diagram of comparative example 1 of the present invention.

[0023] In the figure: 1. Coating layer; 2. PU surface layer; 3. PU foam layer; 4. Base fabric layer. DETAILED DESCRIPTION

[0024] The manufacturers and brands of the formula materials involved in this patent are filled in Table 1.

[0025] Table 1

[0026]

[0027]

[0028] Example 1

[0029] Prepare the PU surface layer: Add 95 parts PU resin, 60 parts DMF, 10 parts ethyl acetate, and 25 parts inorganic colorant to the PU resin, by weight, and stir thoroughly to obtain a PU mixture. Apply the PU mixture to the release paper, maintaining a coating thickness of 0.14 mm and a vehicle speed of 10 m / min. Heat the oven in a stepwise manner, sequentially increasing the temperature to 70°C, 80°C, 100°C, 110°C, 125°C, and 125°C, for a total of 4 minutes, with the same drying time at each temperature setting. This produces the PU surface layer.

[0030] Prepare the PU foam layer: Add 95 parts PU resin, 60 parts DMF, 10 parts ethyl acetate, 25 parts inorganic colorant, 95 parts isocyanate, 48 parts polyol, and 1 part octadecane microsphere powder, by weight, to prepare a solvent-free PU adhesive. Apply this adhesive to the PU top layer to a thickness of 0.24 mm. The vehicle speed was controlled at 9 m / min. The drying temperatures were sequentially set at 100°C, 100°C, 100°C, 110°C, 125°C, and 125°C, with each temperature set for the same time period, to form the PU foam layer.

[0031] Laminating the bamboo fiber base cloth and drying it: Laminate the PU foam layer to the bamboo fiber base cloth, and raise the temperature in the oven in a step-by-step manner at temperatures of 135°C, 135°C, 135°C, 140°C, 140°C, 140°C, 140°C, 145°C, 145°C, 145°C, 145°C, 145°C, and 145°C. The drying time is 12 minutes, and each temperature is set for the same time period. This step is to adhere and fix the PU foam layer and the base cloth layer, separate the release paper, and curl them into PU semi-finished products.

[0032] Finishing and Drying: Add 40 parts by weight of semi-gloss matte surface treatment agent, 45 parts of matte surface treatment agent, 8 parts of hand-feel and wear-resistant agent, 0.2 parts of defoamer, 0.2 parts of antibacterial agent, 0.8 parts of leveling agent, 5 parts of mica powder, 5 parts of cross-linking agent, and 25 parts of industrial distilled water, and stir evenly to obtain the finishing agent. Use a roller coater to apply the finishing agent to the textured surface of the PU semi-finished product. Control the speed at 8m / min and dry the leather at the following temperatures: 125°C, 130°C, 130°C, 130°C, 130°C, 130°C, and 130°C, for 2 minutes. Set each temperature for the same period of time. After drying, curl the leather to obtain a cool PU seat leather.

[0033] Reflectivity test: In accordance with GB / T39370-2020 standard, infrared reflectivity test is performed on the finished product. Prepare a square sample with a length of 300mm and a width of 200mm. Place the test surface upward on the platform, place the integrating sphere flat on the test surface to test the diffuse reflectance, and record the reflectivity. Change the position of the integrating sphere to test 3 positions. The color measurement positions are evenly distributed in the center of the sample. Record the curve as follows: Figure 2 shown.

[0034] Low-wavelength region (around 400-600nm): The reflectivity remains relatively low and stable at around 5%. This indicates that in the blue, green, and yellow regions of the visible light band, the sample's reflectivity is weak, with most of the light being absorbed.

[0035] In the rising wavelength region (around 600-700nm), the reflectivity begins to rise sharply. This indicates that as the wavelength increases, the sample's ability to reflect light rapidly increases, gradually shifting from primarily absorbing light to primarily reflecting light.

[0036] High-wavelength region (around 700-1100nm): After reaching a peak (around 30%-35%), the reflectivity gradually decreases, but overall remains at a relatively high level (around 20%-30%). This wavelength range is in the near-infrared region, indicating that the sample has good reflectivity in the near-infrared range, reflecting more infrared light and reducing heat absorption.

[0037] Temperature monitoring: The temperature of the materials under the above conditions was measured and recorded using an infrared temperature gun, and it was found that the temperature was lower after exposure.

[0038] Example 2

[0039] Prepare the PU top layer: Add 65 parts DMF, 15 parts ethyl acetate, and 25 parts inorganic colorant to 105 parts PU resin and stir thoroughly to obtain a PU mixture. Apply the PU mixture to a release paper liner, maintaining a coating thickness of 0.16 mm and a vehicle speed of 12 m / min. Heat the oven in a stepwise manner, from 70°C, 80°C, 100°C, 110°C, 125°C, and 125°C, for a total of 4 minutes, with the same drying time at each temperature. This produces the PU top layer.

[0040] Prepare the PU foam layer: Add 105 parts PU resin, 65 parts DMF, 15 parts ethyl acetate, 25 parts inorganic colorant, 105 parts isocyanate, 70 parts polyol, and 1 part octadecane microsphere powder, by weight, to make a solvent-free PU adhesive. Apply this adhesive to the PU top layer to a thickness of 0.26 mm. The vehicle speed was controlled at 11 m / min. The drying temperatures were set at 100°C, 100°C, 100°C, 110°C, 125°C, and 125°C, with each temperature set for the same time period.

[0041] Laminating and drying the bamboo fiber fabric: Solvent-free PU adhesive is laminated to the bamboo fiber fabric. The oven temperature is increased in a stepwise manner: 135°C, 135°C, 135°C, 140°C, 140°C, 140°C, 140°C, 140°C, 145 ...

[0042] Finishing and Drying: Add 60 parts by weight of semi-gloss matte surface treatment agent, 60 parts of matte surface treatment agent, 16 parts of hand-feel and wear-resistant agent, 0.3 parts of defoamer, 0.3 parts of antibacterial agent, 1 part of leveling agent, 10 parts of mica powder, 7 parts of cross-linking agent, and 40 parts of industrial distilled water, and stir evenly to obtain the finishing agent. Use a roller coater to apply the finishing agent to the textured surface of the PU semi-finished product. Control the speed at 12m / min and dry the leather at the following temperatures: 125°C, 130°C, 130°C, 130°C, 130°C, and 130°C, for 3 minutes. Set each temperature for the same period of time. After drying, curl the leather to obtain a cool PU seat leather.

[0043] Reflectivity test: In accordance with GB / T39370-2020 standard, infrared reflectivity test is performed on the finished product. Prepare a square sample with a length of 300mm and a width of 200mm. Place the test surface upward on the platform, place the integrating sphere flat on the test surface to test the diffuse reflectance, and record the reflectivity. Change the position of the integrating sphere to test 3 positions. The color measurement positions are evenly distributed in the center of the sample. Record the curve as follows: Figure 3 shown.

[0044] Low-wavelength region (around 400-600nm): The reflectivity remains relatively low and stable at around 5%. This indicates that in the blue, green, and yellow regions of the visible light band, the sample's reflectivity is weak, with most of the light being absorbed.

[0045] In the rising wavelength region (around 600-700nm), the reflectivity begins to rise sharply. This indicates that as the wavelength increases, the sample's ability to reflect light rapidly increases, gradually shifting from primarily absorbing light to primarily reflecting light.

[0046] High-wavelength region (around 700-1100nm): After reaching a peak (around 30%-35%), the reflectivity gradually decreases, but overall remains at a relatively high level (around 20%-30%). This wavelength range is in the near-infrared region, indicating that the sample has good reflectivity in the near-infrared range, reflecting more infrared light and reducing heat absorption.

[0047] Temperature monitoring: The temperature of the material under the above conditions was measured and recorded using an infrared temperature measuring gun. It was found that the temperature after exposure was lower than that in Example 1.

[0048] Example 3

[0049] The difference between Example 3 and Example 1 is that the amount of octadecane microsphere powder is increased to 3 parts. Its infrared reflectivity curve is the same as that of Example 1, but the temperature monitoring shows that it is lower than that of Example 1.

[0050] Comparative Example 1

[0051] The only difference between Comparative Example 1 and Example 1 is that the components lack mica powder and octadecane microsphere powder, and the preparation method is the same as that of Example 1.

[0052] Wavelength range (400-1100nm): The reflectivity remains relatively low and stable at around 4%. This indicates that in the blue, green, and yellow regions of the visible light band, the sample's reflectivity is weak, with most light being absorbed.

[0053] Temperature monitoring: The temperature of the material under the above conditions was measured and recorded using an infrared temperature measuring gun. It was found that the temperature after exposure was higher than that of Examples 1, 2, and 3.

[0054] Combine Examples 1 and 2 with Comparative Example 1 and Table 2 as follows:

[0055] Table 2

[0056]

[0057] Mica powder was added to both Examples 1 and 2, and the near-infrared reflectivity was significantly improved (20% to 35%), indicating that mica powder reduces heat absorption by reflecting infrared rays and is a key component in achieving a "cool feeling". The reflectivity of Example 2 was higher than that of Example 1, indicating that the higher the mica content within a certain range, the better the reflective effect.

[0058] Comparative Example 1 does not contain mica powder, and the reflectivity is only 4%, which proves that mica powder plays a decisive role in the thermal insulation performance.

[0059] In Example 1 (1 part octadecane microsphere powder) and Example 3 (3 parts octadecane microsphere powder), the octadecane microsphere powder can reduce the temperature through phase change. Example 3 has a better cooling effect due to the larger amount of microsphere powder used.

Claims

1. A cool feeling PU, characterized in that: From top to bottom, it includes coating layer, PU surface layer, PU foam layer and base fabric layer; The raw materials of the finishing layer include the following components in parts by weight: 40-60 parts of semi-bright matte surface treatment agent, 45-60 parts of matte surface treatment agent, 8-16 parts of hand feeling and wear resistance agent, 0.2-0.3 parts of defoaming agent, 0.2-0.3 parts of antibacterial agent, 0.8-1 parts of leveling agent, 5-7 parts of cross-linking agent, 5-10 parts of mica powder, and 25-40 parts of industrial distilled water; The raw materials of the PU surface layer include the following components in parts by weight: 95-105 parts of PU resin, 60-65 parts of DMF, 10-15 parts of ethyl acetate, and 25-40 parts of color paste; The PU foam layer comprises the following components in parts by weight: 95-105 parts of PU resin, 60-65 parts of DMF, 10-15 parts of ethyl acetate, 25-40 parts of color paste, 95-105 parts of solvent-free adhesive material A, 48-70 parts of solvent-free adhesive material B, 1-3 parts of octadecane microspheres, 0.04-0.06 parts of accelerator, 0.18-0.3 parts of curing agent, 0.15-0.25 parts of leveling agent, and 35-50 parts of flame retardant.

2. The cool feeling PU according to claim 1, characterized in that: The solvent-free adhesive material A is isocyanate, and the solvent-free adhesive material B is polyol.

3. The cool feeling PU according to claim 1, characterized in that: The base fabric layer is a bamboo fiber base fabric.

4. A method for preparing the cool feeling PU according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Preparation of PU surface layer: DMF, ethyl acetate, and color paste were added to the PU resin according to the weight ratio of the formula, and the mixture was stirred to obtain a PU mixture. The PU mixture was applied to the release paper with a coating thickness of 0.15±0.01mm and a speed of 11±1m / min. The temperature was increased in a stepwise manner to 70 / 80 / 100 / 110 / 125 / 125°C for a total of 4 minutes. Each temperature was set for the same time period to obtain the PU surface layer. S2: Adding PU foam layer: According to the weight ratio of the formula, the raw materials of the PU foam layer are mixed evenly and applied to the surface of the PU surface layer. The coating thickness is 0.25±0.01mm. The vehicle speed is controlled at 10±1m / min. The temperature is stepped and heated and dried at 100 / 100 / 100 / 110 / 125 / 125℃ in sequence. The drying time is 15min in total. Each temperature is set for the same time period to obtain the PU foam layer. S3: Adding base fabric layer: Lay one side of the PU foam layer on the base fabric, and heat and dry it in a step-by-step manner at the following temperatures: 135 / 135 / 135 / 140 / 140 / 140 / 140 / 140 / 145 / 145 / 145 / 145 / 145°C, and dry for 12 minutes. Set each temperature for the same time period, then separate the release paper, curl it, and make a PU semi-finished product. The side of the separated release paper has a PU texture surface. S4: Finishing layer: Mix the raw materials of the aqueous treatment layer evenly according to the weight ratio of the formula, and then use a roller coater to apply it to the PU surface layer side of the PU semi-finished product. The speed is controlled at 10±2m / min, and the temperature is stepped and heated and dried. The drying temperatures are 125 / 130 / 130 / 130 / 130 / 130℃ in sequence, and the drying time is 2-3min. Each temperature is set for the same time period, and curled after drying.

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