A coating with high flexibility and rubbing fastness, its preparation method and application

Abstract

The application discloses a paint with high flexibility and rubbing color fastness as well as a preparation method and application thereof. The preparation raw materials of the paint include the following components in parts by weight: 40-50 parts of water-based aliphatic polyether type polyurethane resin, 30-40 parts of nano color paste, 1-2 parts of defoaming agent, 1-2 parts of wetting agent, 2-3 parts of phosphate ester compound, 3-4 parts of blocked isocyanate, 2-3 parts of dispersing agent, 5-10 parts of water, and 0.1-0.3 parts of pH regulator. The paint is used for coloring the surface of carbon fiber fabric through a dipping process, and the product obtained after baking has high flexibility and can still maintain the good flexibility and bending property of the fabric itself. The paint has good adhesion and appearance on the carbon fiber fabric, has high rubbing color fastness, and the rubbing color fastness can reach grade 4-5, so that the color can be firmly attached to the surface of the carbon fiber fabric, and the color will not be dropped after coloring and assembling.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and particularly relates to a coating with high flexibility and rubbing color fastness, its preparation method and application. Background Technology

[0002] Applying color to fabrics not only enhances their appearance but also creates a wide variety of effects. Fabrics come in a diverse range of materials, including cotton, synthetic fibers, animal hair, silk, and the increasingly popular carbon fiber, which is also used in fabrics across various fields.

[0003] Fabrics can be dyed through various methods, including printing and dyeing, and dipping. Fabric printing and dyeing has a history spanning thousands of years. Modern mechanical printing and dyeing is time-saving and efficient, producing bright colors with high colorfastness and fixation. However, it does not meet environmental protection requirements because it uses harmful substances such as adhesives and colorants. Dipping is characterized by high production efficiency, environmental friendliness and energy saving, simple operation, and minimal paint loss. Compared to printing and dyeing, dipping can only coat the surface with the same color, but it produces less pollution. However, dipping-coated fabrics have a rougher hand feel and poorer colorfastness to rubbing, limiting its widespread acceptance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a coating with high flexibility and rubbing color fastness, its preparation method and application.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0006] A coating with high flexibility and color fastness to rubbing, wherein the raw materials for preparation include the following components in parts by weight:

[0007] 40-50 parts of waterborne aliphatic polyether polyurethane resin, 30-40 parts of nano-color paste, 1-2 parts of defoamer, 1-2 parts of wetting agent, 2-3 parts of phosphate ester compound, 3-4 parts of blocked isocyanate, 2-3 parts of dispersant, 5-10 parts of water, and 0.1-0.3 parts of pH adjuster.

[0008] As a further improvement, the waterborne aliphatic polyether polyurethane resin has a 100% modulus of 1-1.5 MPa, a tensile strength of 8-15 MPa, and an elongation of 800-1000%.

[0009] As a further improvement, the waterborne aliphatic polyether polyurethane resin is Stahl's Permutex RU-4049; and / or

[0010] The nano pigment used is G7007-SC from Guangdong Kedi Company.

[0011] As a further improvement, the waterborne aliphatic polyether polyurethane resin is 45-50 parts by weight, and the nano-color paste is 30-35 parts by weight.

[0012] As a further improvement, the phosphate compound is from Lubrizol. 2063.

[0013] As a further improvement, the blocked isocyanate is a blocked aliphatic isocyanate, specifically Covestro's BAYHYDUR BL 2867.

[0014] As a further improvement, the defoamer is selected from one or more of Tego810 and Tego902W from Tego Chemicals and BYK024 from BYK Chemicals; and / or

[0015] The wetting agent is selected from Greesol GS195 from Yueyang Kaimen; and / or

[0016] The dispersant is selected from one or more of BYK 2012 and BYK 2013; and / or

[0017] The pH adjuster used is DMEA.

[0018] The present invention also provides a method for preparing the aforementioned high flexibility and rubbing color fastness coating, comprising the following steps:

[0019] (1) Add the nano color paste to the water-based aliphatic polyether polyurethane resin and stir. The stirring speed is 300-500 rpm and the stirring time is 3-5 minutes.

[0020] (2) Add defoamer, wetting agent, phosphate ester compound and blocked isocyanate and stir at a stirring speed of 600-800 rpm for 5-8 minutes;

[0021] (3) Add dispersant and stir at a speed of 800-1000 rpm for 10-20 minutes;

[0022] (4) Add water and pH adjuster, mix well, and filter to obtain the final product.

[0023] The present invention also provides an application of the aforementioned high flexibility and rubbing fastness coating in carbon fiber materials.

[0024] As a further improvement, the coating is applied to the carbon fiber fabric by dip coating and then baked to cure.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The high-flexibility and rubbing fastness coating of this invention is applied to the surface of carbon fiber fabrics via a dip-coating process. After baking, the resulting product exhibits high flexibility; the coating's flexibility is close to that of the fabric itself, maintaining the fabric's good suppleness and bendability. The coating shows good adhesion and appearance on carbon fiber fabrics, exhibiting high rubbing fastness (4-5 grades), ensuring the color adheres firmly to the fabric surface and does not fade after assembly. Furthermore, the coating meets high-temperature and neutral salt spray resistance tests. In addition, this invention uses a water-based PU system with VOC < 100g / L, far below national standards, meeting environmental protection requirements. Detailed Implementation

[0027] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0028] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0029] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0030] The high flexibility and rubbing fastness coating of some specific embodiments of the present invention comprises the following raw materials by weight: 40-50 parts (preferably 45-50) of waterborne aliphatic polyether polyurethane resin, 30-40 parts (preferably 30-35) of nano-color paste, 1-2 parts of defoamer, 1-2 parts of wetting agent, 2-3 parts of phosphate ester compound, 3-4 parts of blocked isocyanate, 2-3 parts of dispersant, 5-10 parts of water, and 0.1-0.3 parts of pH adjuster.

[0031] In some specific embodiments, the waterborne aliphatic polyether polyurethane resin of the present invention has a 100% modulus of 1-1.5 MPa, a tensile strength of 8-15 MPa, and an elongation of 800-1000%, making it suitable for systems requiring high flexibility. It exhibits good adhesion to synthetic and natural fibers, as well as fabrics, leather, and other materials. Specifically, Stahl's Permutex RU-4049 can meet the above requirements, with a 100% modulus of 1.2 MPa, a tensile strength of 10.0 MPa, an elongation of 900%, a viscosity of 600 mPa·s at 25°C, facilitating application, 0.9% volatile organic compounds (VOCs), meeting the environmental requirements of waterborne systems, and a solid content of 40%.

[0032] In some specific embodiments, the nano-pigment of the present invention can be G7007-SC produced by Guangdong Kedi Company, which has a solid content of 45%, lightfastness grade 8, chemical resistance grade 5, acid and alkali resistance grade 5, and heat resistance of 220℃.

[0033] In some specific embodiments, the defoamer used in this invention is one or more of polyether siloxane copolymers and polydimethylsiloxane. Specifically, one or more of Tego810 and Tego902W from Tego and BYK024 from BYK Chemical can be selected.

[0034] In some specific embodiments, the wetting agent used in this invention is an organosiloxane surfactant developed based on Gemini technology, which has excellent anti-oil and anti-cratering capabilities, specifically Greesol GS195 from Yueyang Kaimen.

[0035] The phosphate ester compound used in this invention contains various organic substituent groups and phosphate groups that can react with inorganic metal substrates in an acid-base reaction. Due to the high reactivity of phosphate groups, minor defects on the metal substrate surface, such as slight rusting, peeling, and blistering, can be addressed by forming chemical bonds through the chemical reaction between phosphate groups and the metal surface, thus enhancing adhesion. Since the carbon fiber fabric surface has a layer of aluminum plating, using phosphate ester compounds can also increase the adhesion between the coating and the carbon fiber, resulting in higher color fastness to rubbing. Specifically, Lubrizol's phosphate ester compounds can be used... 2063 has an acid value of 50 mg KOH / g and is suitable for water-based coating systems.

[0036] In some specific embodiments, the blocked isocyanate used in this invention is a blocked aliphatic isocyanate, specifically Covestro's BAYHYDUR BL 2867, which does not contain organic solvents and is dispersed in an aqueous solution (approximately 38 wt%) before use.

[0037] In some specific embodiments, the dispersant used in this invention is one or more of the following: a high molecular weight block copolymer solution, a copolymer containing pigment affinity groups, and an organically modified polyacrylate solution containing pigment affinity groups. The dispersant ensures the prepared coating has strong uniformity, a fine texture, and does not exhibit uneven coloring. Specifically, one or more of BYK's BYK2012 and BYK2013 can be used.

[0038] In some specific embodiments, the pH adjuster used in this invention is an amine neutralizer, which mainly serves to adjust the pH of the coating to a weakly alkaline range, which is beneficial for the storage of water-based coatings, improves activation, and prevents sedimentation. Specifically, DMEA can be used.

[0039] The coating of this invention is applied to carbon fiber. The coating film needs to balance flexibility and a certain strength to meet the rubbing fastness test. During the development process, it was found that the ratio of waterborne aliphatic polyether polyurethane resin to nano-pigment paste is particularly important. The ratio needs to be in the range of 1 / 1 to 5 / 3 to obtain the required effect. When the ratio is lower than the range, the pigment-to-binder ratio is too high, the resin cannot fully encapsulate the pigment groups, the staining is obvious in the high temperature test, and the rubbing fastness test is NG. When the ratio is higher than the range, the pigment-to-binder ratio is too low, the coloring power of the coating on the substrate is insufficient, and the rubbing fastness test is NG.

[0040] Furthermore, the amount of phosphate ester and blocked isocyanate added is particularly important; only by adding them within the scope of this invention can the desired effect be obtained. If the amount added is too small, the number of chemical bonds formed between the phosphate group and the substrate will be insufficient, and the number of NCO groups formed after the blocked isocyanate is unblocked will also be insufficient. This results in a low crosslinking density of the coating, insufficient adhesion to the substrate, leading to failure in the rubbing color fastness test and bubbling in the salt spray test. If the amount added is too large, the crosslinking density of the coating will be high, leading to failure in the flexibility test.

[0041] The preparation method of the coating with high flexibility and rubbing color fastness according to some specific embodiments of the present invention includes the following steps:

[0042] (1) Add the nano color paste to the water-based aliphatic polyether polyurethane resin and stir. The preferred stirring speed is 300-500 rpm and the stirring time is 3-5 minutes.

[0043] (2) Add defoamer, wetting agent, phosphate ester and blocked isocyanate and stir, preferably at a stirring speed of 600-800 rpm and a stirring time of 5-8 minutes;

[0044] (3) Add dispersant and stir, preferably at a stirring speed of 800-1000 rpm for 10-20 minutes;

[0045] (4) Add water and pH adjuster, mix well, and filter to obtain the final product.

[0046] The application method of the high flexibility and rubbing fastness coating of the present invention is as follows: the coating is mixed with water to a suitable viscosity for application, coated onto carbon fiber fabric by dip coating, and baked at 120-180°C for 8-15 minutes to obtain a dry film.

[0047] Examples and Comparative Examples

[0048] The high flexibility and rubbing color fastness coating of this embodiment and the coating of the comparative example have the following compositions as shown in Table 1:

[0049] Table 1. Parts by weight of each component in the Examples and Comparative Examples

[0050]

[0051]

[0052] Preparation methods of the above embodiments and comparative examples:

[0053] S1. Add the aqueous aliphatic polyether polyurethane resin from the components to the dispersion container;

[0054] S2. Add the nano colorant at a slow speed of 300-500 rpm, stir for 3-5 minutes, and be careful to scrape the edges.

[0055] S3. Then add defoamer, wetting agent, phosphate ester and blocked isocyanate (38wt%) at 600-800 rpm, and stir for 5-8 minutes.

[0056] S4. Increase the speed to 800-1000 rpm and add the dispersant. Stir at high speed for 10-20 minutes. Since the temperature continues to rise during high-speed dispersion, pay attention to cooling down during the process to prevent the resin from breaking down due to excessive temperature.

[0057] S5. Add deionized water and pH adjuster. Premix the deionized water and pH adjuster and let them stand at room temperature for 5 minutes (or until the temperature is suitable) before adding them. Adjust the pH with the pH adjuster and adjust the viscosity with deionized water.

[0058] The temperature was controlled between 5-35℃ throughout the process;

[0059] S6. Filter and package the product using a 250-350 mesh filter to obtain the coatings of the examples and comparative examples.

[0060] Construction methods of the above embodiments and comparative examples:

[0061] The coatings prepared in Examples 1-4 and Comparative Examples 1-4 were mixed with water to a suitable viscosity for application, and then coated onto carbon fiber fabric by dip coating. The film thickness was 20-40 μm. After baking at 150°C for 10 min, the final dry film was obtained.

[0062] The performance test items are shown in Table 2:

[0063] Table 2 Performance Test Results

[0064]

[0065]

[0066] As can be seen, in Comparative Example 1, the ratio of waterborne aliphatic polyether polyurethane resin to nano-pigment paste was too small, resulting in low rubbing fastness and obvious staining during high-temperature testing. The amount of waterborne aliphatic polyether polyurethane resin was also too small, leading to poor flexibility and low conventional adhesion. In Comparative Example 2, the ratio of waterborne aliphatic polyether polyurethane resin to nano-pigment paste was too large, resulting in low rubbing fastness. Furthermore, due to this large ratio, the paint film failed to fully cure at the aforementioned baking time, resulting in insufficient cross-linking density and slightly poor performance in both high-temperature testing and conventional adhesion. In Comparative Example 3, the amount of phosphate ester and blocked isocyanate was too small, resulting in insufficient adhesion, poor rubbing fastness, and poor salt spray resistance. Additionally, the insufficient amount of these components led to insufficient cross-linking density in the paint film, causing pigment leaching and obvious staining during high-temperature testing. In Comparative Example 4, the amount of phosphate ester and blocked isocyanate was too large, resulting in poor flexibility. Furthermore, the excessive amount of these components made the paint film too hard and brittle, causing chipping during the cross-linking test and slightly poor adhesion results.

[0067] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A coating with high flexibility and color fastness to rubbing, characterized in that, Its preparation raw materials include the following components in parts by weight: 45-50 parts of waterborne aliphatic polyether polyurethane resin, 30-35 parts of nano-color paste, 1-2 parts of defoamer, 1-2 parts of wetting agent, 2-3 parts of phosphate ester compound, 3-4 parts of blocked isocyanate, 2-3 parts of dispersant, 5-10 parts of water, and 0.1-0.3 parts of pH adjuster. The waterborne aliphatic polyether polyurethane resin has a 100% modulus of 1~1.5 MPa, a tensile strength of 8~15 MPa, and an elongation of 800~1000%. The coating is applied to the surface of the carbon fiber fabric and then cured by baking.

2. The coating with high flexibility and color fastness to rubbing according to claim 1, characterized in that, The aqueous aliphatic polyether polyurethane resin used is Stahl's Permutex RU-4049; and / or The nano pigment used is G7007-SC from Guangdong Kedi Company.

3. The coating with high flexibility and rubbing fastness according to claim 1 or 2, characterized in that, The phosphate compound used is Lubrizol® 2063 from Lubrizol.

4. The coating with high flexibility and rubbing fastness according to claim 1 or 2, characterized in that, The blocked isocyanate is a blocked aliphatic isocyanate, specifically Covestro's BAYHYDUR BL 2867.

5. The coating with high flexibility and rubbing fastness according to claim 1 or 2, characterized in that, The defoamer is selected from one or more of Tego810 and Tego902W from Tego and BYK024 from BYK Chemical; and / or The wetting agent is selected from Greesol GS195 from Yueyang Kaimen; and / or The dispersant is selected from one or more of BYK 2012 and BYK 2013; and / or The pH adjuster used is DMEA.

6. A method for preparing a coating with high flexibility and rubbing color fastness according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Add the nano pigment to the water-based aliphatic polyether polyurethane resin and stir. The stirring speed is 300~500 rpm and the stirring time is 3~5 minutes. (2) Add defoamer, wetting agent, phosphate ester compound and blocked isocyanate and stir at a speed of 600~800 rpm for 5~8 minutes; (3) Add dispersant and stir at a speed of 800-1000 rpm for 10-20 minutes; (4) Add water and pH adjuster, mix well, and filter to obtain the final product.

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