Environment-friendly coating material and its application on wood surface

Abstract

The present application provides an environment-friendly coating material and its application on wood surface, the coating material comprises the following components by mass percentage: modified castor oil 10-20%; inorganic nanoparticles 20-30%; combination of epoxy soybean oil and soybean oil based polyol 30%-40%; lignin 10-20%; the degree of epoxidation of the epoxy soybean oil is 2%-5%; the hydroxyl value of the soybean oil based polyol is 150-250 mg KOH / g; the acid value of the modified castor oil is <1.0 mg KOH / g, and the iodine value is 100-150. The environment-friendly coating material of the present application takes into account both environmental protection and performance, realizes efficient coating application on wood surface by optimizing component ratio and material properties, has excellent adhesion, gloss, water resistance, chemical resistance and scratch resistance, and can meet the market demand of modern environment-friendly coating materials.

Description

Technical Field

[0001] This invention relates to a coating material, and more specifically to an environmentally friendly coating material and its application on wood surfaces. Background Technology

[0002] With increasing environmental awareness and the global consensus on green and sustainable development, traditional industries, especially the building decoration materials industry, are facing pressure to transform and upgrade. Coating materials, as an important component of decorative materials, play a crucial role in interior and exterior decoration, furniture manufacturing, and other wood-based decorative products. However, traditional coating materials often contain large amounts of organic solvents and toxic compounds, such as formaldehyde, benzene, and their derivatives. These substances can pose threats to the environment and human health during production, use, and disposal.

[0003] In response to this issue, the research and development of environmentally friendly coating materials has become a focus of attention both within and outside the industry. The development of environmentally friendly coating materials aims to reduce or eliminate the use of harmful chemicals, achieve low volatile organic compound (VOC) emissions, and at the same time ensure that the coating effect and durability of the materials are no less than those of traditional coatings, so as to meet the requirements of modern society for environmental protection and indoor air quality.

[0004] In wood surface applications, due to the natural characteristics and diverse uses of wood, the performance requirements for coating materials are relatively more stringent. Wood surface coatings must not only provide an aesthetically pleasing appearance but also offer long-term protection, such as moisture resistance, mildew prevention, and UV resistance, preventing wood deformation, decay, or discoloration. Therefore, developing an environmentally friendly coating material that meets environmental requirements while effectively protecting wood and enhancing its aesthetics is of great significance for promoting the sustainable development of green building and the furniture industry. Summary of the Invention

[0005] To address the problems existing in the current technology, an environmentally friendly coating material and its application on wood surfaces are provided, with the specific solution as follows:

[0006] An environmentally friendly coating material, comprising the following components by weight percentage:

[0007] 10-20% modified castor oil;

[0008] Inorganic nanoparticles 20-30%;

[0009] The composition of epoxidized soybean oil and soybean oil-based polyols is 30%–40%.

[0010] Lignin 10-20%;

[0011] The epoxidation degree of the epoxidized soybean oil is 2% to 5%; the hydroxyl value of the soybean oil-based polyol is 150 to 250 mg KOH / g.

[0012] The modified castor oil has an acid value of <1.0 mg KOH / g and an iodine value of 100-150.

[0013] Furthermore, the inorganic nanoparticles are a combination of silicon dioxide, zinc oxide, titanium oxide, copper oxide, and iron oxide.

[0014] Furthermore, the mass ratio of epoxidized soybean oil to soybean oil-based polyol is 1:1 to 2:1.

[0015] Furthermore, the preparation method of modified castor oil includes the following steps:

[0016] S1. Pretreatment of castor oil: The castor oil is heated at 70-80℃;

[0017] S2. Modification reaction: Heated castor oil and methanol are mixed at a molar ratio of 1:6, and 1% sodium hydroxide is added as a catalyst; the mixture is stirred at 60-70°C for 4-6 hours.

[0018] S3. Epoxidation reaction: After the reaction is complete, raise the system temperature to 80-90℃ and gradually add excess hydrogen peroxide; add 0.1-0.5% catalyst and stir the reaction at a controlled temperature for 6-8 hours.

[0019] S4. Post-treatment: Cool the system to room temperature and wash the reactants with an equal volume of hot water to remove the catalyst and residual reaction byproducts.

[0020] Furthermore, in S3, based on the unsaturated double bonds of castor oil, the molar ratio of hydrogen peroxide to double bonds is 1.2:1.

[0021] Furthermore, the catalyst in S3 is phosphotungstic acid or molybdate.

[0022] The application of an environmentally friendly coating material to wood surfaces includes the following steps:

[0023] S1. Surface pretreatment: First, the wood surface is sanded, dusted, and cleaned.

[0024] S2. Coating preparation: Based on the required coverage area and usage conditions, mix the modified castor oil, inorganic nanoparticles, epoxidized soybean oil and soybean oil-based polyol composition and lignin according to the mass percentage, and stir thoroughly to obtain an environmentally friendly coating material.

[0025] S3. Coating Implementation: Apply the mixed coating material evenly to the wood surface using a brush, roller, or spraying equipment;

[0026] S4. Drying and curing: After coating, the wood is placed at room temperature to dry naturally or dried in an oven at 50-60℃ until the surface is no longer noticeably sticky. The drying time is 24-48 hours.

[0027] Beneficial effects:

[0028] This invention provides an environmentally friendly coating material that, through the optimization and proportioning of specific components, achieves both high performance and environmental protection requirements and has the following beneficial effects:

[0029] (1) Modified castor oil improved the adhesion and flexibility of the coating material. The acid value was controlled below 1.0 mg KOH / g, ensuring the stability and durability of the material, thereby reducing coating embrittlement and cracking. An iodine value in the range of 100–150 indicated a moderate level of unsaturation in the modified castor oil, which helps resist environmental factors from corroding the coating and provides good weather resistance.

[0030] (2) A composition of epoxidized soybean oil and soybean oil-based polyol was added, and the epoxidation degree of the epoxidized soybean oil was optimized to 2%–5% to ensure sufficient cross-linking density, resulting in a coating with good mechanical strength and chemical resistance. The hydroxyl value of the soybean oil-based polyol was 150–250 mg KOH / g, which facilitated a more effective cross-linking reaction with the epoxidized soybean oil, further improving the overall performance of the coating. At the same time, the mass ratio of epoxidized soybean oil to soybean oil-based polyol was adjusted so that the coating could maintain its flexibility while improving its hardness and abrasion resistance.

[0031] (3) The introduction of lignin, as a natural polymer compound, not only increases the UV absorption capacity of the coating and improves the sun protection effect, but also enhances the biodegradability of the coating material, meeting environmental protection requirements. At the same time, lignin can also improve the waterproof and anti-corrosion properties of the coating, making the wood surface more durable and extending its service life. Detailed Implementation

[0032] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0033] Example 1:

[0034] The specific steps for preparing environmentally friendly coating materials are as follows:

[0035] (1) Take 15% (mass percentage) of modified castor oil, 25% of inorganic nanoparticles, 35% of the composition of epoxidized soybean oil and soybean oil-based polyol, and 15% of lignin.

[0036] (2) Preparation of modified castor oil:

[0037] S1: Heat castor oil to 75°C;

[0038] S2: Add castor oil and methanol in a molar ratio of 1:6, and add 1% sodium hydroxide as a catalyst. Stir and react at 65°C for 5 hours.

[0039] S3: Raise the temperature of the reaction system to 85℃, slowly add hydrogen peroxide with a molar ratio of 1.2:1 to the unsaturated double bonds of castor oil, and add 0.3% phosphotungstic acid as a catalyst, and continue stirring the reaction for 7 hours;

[0040] S4: Cool the reactants to room temperature and wash them with an equal volume of 80°C hot water to remove the catalyst and reaction byproducts.

[0041] (3) Mix all components according to the above mass percentages and stir thoroughly to ensure uniformity.

[0042] (4) Apply the coating to the wood surface by brushing. The amount of coating is approximately 150 grams per square meter.

[0043] (5) Place the coated wood in an indoor environment to air dry for 48 hours to ensure that the coating is completely dry and cured.

[0044] Example 2:

[0045] The specific steps for preparing environmentally friendly coating materials are as follows:

[0046] (1) Take 12% (mass percentage) of modified castor oil, 30% of inorganic nanoparticles, 40% of the composition of epoxidized soybean oil and soybean oil-based polyol, and 18% of lignin.

[0047] (2) Preparation of modified castor oil:

[0048] S1: Heat castor oil to 70°C;

[0049] S2: Add castor oil and methanol in a molar ratio of 1:6, and add 1% sodium hydroxide as a catalyst. Stir and react at 60°C for 4 hours.

[0050] S3: Raise the temperature of the reaction system to 80℃, slowly add hydrogen peroxide with a molar ratio of 1.2:1 to the unsaturated double bonds of castor oil, and add 0.1% molybdate as a catalyst, and continue stirring the reaction for 6 hours;

[0051] S4: Cool the reactants to room temperature and wash them with an equal volume of 70°C hot water to remove the catalyst and reaction byproducts.

[0052] (3) Mix all components according to the above mass percentages and stir thoroughly to ensure uniformity.

[0053] (4) Apply the coating to the wood surface by spraying. The amount of coating is approximately 180 grams per square meter.

[0054] (5) Place the coated wood in an indoor environment to air dry for 24 hours to ensure that the coating is completely dry and cured.

[0055] Example 3:

[0056] The specific steps for preparing environmentally friendly coating materials are as follows:

[0057] (1) Take 20% (by mass) of modified castor oil, 20% of inorganic nanoparticles, 30% of a combination of epoxidized soybean oil and soybean oil-based polyol, and 10% of lignin.

[0058] (2) Preparation of modified castor oil:

[0059] S1: Heat castor oil to 80°C;

[0060] S2: Add castor oil and methanol in a molar ratio of 1:6, and add 1% sodium hydroxide as a catalyst. Stir and react at 70°C for 6 hours.

[0061] S3: Raise the temperature of the reaction system to 90℃, slowly add hydrogen peroxide with a molar ratio of 1.2:1 to the unsaturated double bonds of castor oil, and add 0.5% phosphotungstic acid as a catalyst, and continue stirring the reaction for 8 hours;

[0062] S4: Cool the reactants to room temperature and wash them with an equal volume of 90°C hot water to remove the catalyst and reaction byproducts.

[0063] (3) Mix all components according to the above mass percentages and stir thoroughly to ensure uniformity.

[0064] (4) Apply the coating to the wood surface using a roller coating method, with a coating amount of approximately 200 grams per square meter.

[0065] (5) Place the coated wood in an oven at 50-60℃ and dry it until the surface is no longer sticky. The drying time is about 24 hours.

[0066] Example 4:

[0067] The specific steps for preparing environmentally friendly coating materials are as follows:

[0068] (1) Take 10% (mass percentage) of modified castor oil, 22% of inorganic nanoparticles, 38% of the composition of epoxidized soybean oil and soybean oil-based polyol, and 20% of lignin.

[0069] (2) Preparation of modified castor oil:

[0070] S1: Heat castor oil to 75°C;

[0071] S2: Add castor oil and methanol in a molar ratio of 1:6, and add 1% sodium hydroxide as a catalyst. Stir and react at 65°C for 5 hours.

[0072] S3: Raise the temperature of the reaction system to 85℃, slowly add hydrogen peroxide with a molar ratio of 1.2:1 to the unsaturated double bonds of castor oil, and add 0.4% phosphotungstic acid as a catalyst, and continue stirring the reaction for 7 hours;

[0073] S4: Cool the reactants to room temperature and wash them with an equal volume of 80°C hot water to remove the catalyst and reaction byproducts.

[0074] (3) Mix all components according to the above mass percentages and stir thoroughly to ensure uniformity.

[0075] (4) Apply the coating to the wood surface by brushing. The amount of coating is approximately 120 grams per square meter.

[0076] (5) Place the coated wood in an indoor environment to air dry for 48 hours to ensure that the coating is completely dry and cured.

[0077] Example 5:

[0078] The specific steps for preparing environmentally friendly coating materials are as follows:

[0079] (1) Take 18% (mass percentage) of modified castor oil, 28% of inorganic nanoparticles, 34% of the composition of epoxidized soybean oil and soybean oil-based polyol, and 20% of lignin.

[0080] (2) Preparation of modified castor oil:

[0081] S1: Heat castor oil to 78°C;

[0082] S2: Add castor oil and methanol in a molar ratio of 1:6, and add 1% sodium hydroxide as a catalyst. Stir and react at 67°C for 5.5 hours.

[0083] S3: Raise the temperature of the reaction system to 88℃, slowly add hydrogen peroxide with a molar ratio of 1.2:1 to the unsaturated double bonds of castor oil, and add 0.2% molybdate as a catalyst, and continue stirring the reaction for 7.5 hours;

[0084] S4: Cool the reactants to room temperature and wash them with an equal volume of 85°C hot water to remove the catalyst and reaction byproducts.

[0085] (3) Mix all components according to the above mass percentages and stir thoroughly to ensure uniformity.

[0086] (4) Apply the coating to the wood surface by spraying. The amount of coating is approximately 160 grams per square meter.

[0087] (5) Place the coated wood in an indoor environment to air dry for 36 hours to ensure that the coating is completely dry and cured.

[0088] Comparative Example 1:

[0089] The preparation method is similar to that in Example 1, except that the castor oil in the raw materials is not modified.

[0090] Comparative Example 2:

[0091] The preparation method is similar to that in Example 1, except that modified castor oil was not added.

[0092] Comparative Example 3:

[0093] The preparation method is similar to that in Example 1, except that the combination of epoxidized soybean oil and soybean oil-based polyol is not added to the raw materials.

[0094] The wood coated in Examples 1-5 and Comparative Examples 1-3 was subjected to performance testing, and the test results are as follows:

[0095]

[0096] In summary, the coating materials of Examples 1-5 outperformed the comparative examples in multiple performance tests, indicating that the formulations of the examples improved the overall performance of the coating materials.

[0097] As a further improvement, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly coating material, characterized by comprising: The coating material comprises the following components by mass percentage: Modified castor oil 10-20%; Inorganic nanoparticles 20-30%; Epoxy soybean oil and soybean oil-based polyol composition 30%-40%; Lignin 10-20%; The degree of epoxidation of the epoxy soybean oil is 2%-5%, and the hydroxyl value of the soybean oil-based polyol is 150-250 mg KOH / g; The modified castor oil has an acid value <1.0 mg KOH / g and an iodine value of 100-150.

2. The environmentally friendly coating material according to claim 1, characterized in that, The inorganic nanoparticles are a combination of silicon dioxide, zinc oxide, titanium oxide, copper oxide, and iron oxide.

3. The environmentally friendly coating material according to claim 1, characterized in that, The mass ratio of the epoxy soybean oil to the soybean oil-based polyol is 1:1 to 2:

1.

4. The environmentally friendly coating material according to claim 1, characterized in that, The preparation method of the modified castor oil comprises the following steps: S1, pretreatment of castor oil: heat the castor oil at 70-80°C; S2, modification reaction: mix the heated castor oil with methanol at a molar ratio of 1:6, add 1% sodium hydroxide as a catalyst, and stir and react at 60-70°C for 4-6 hours; S3, epoxidation reaction: after the reaction is completed, increase the temperature of the system to 80-90°C, gradually add excess hydrogen peroxide, and add 0.1-0.5% catalyst to stir and react at a controlled temperature for 6-8 hours; S4, post-treatment: cool the system to room temperature, and wash the reaction product with an equal volume of hot water to remove the catalyst and residual reaction byproducts.

5. The environmentally friendly coating material according to claim 4, characterized in that, In S3, the molar ratio of hydrogen peroxide to double bonds based on the unsaturated double bonds of castor oil is 1.2:

1.

6. The environmentally friendly coating material according to claim 4, characterized in that, The catalyst in S3 is phosphotungstic acid or silicon molybdate.

7. The use of the environmentally friendly coating material according to claims 1 to 6 on the surface of wood, characterized in that, The method comprises the following steps: S1, surface pretreatment: first polish, dust, and clean the surface of the wood; S2, coating preparation: according to the area to be covered and the use conditions, mix the modified castor oil, inorganic nanoparticles, epoxy soybean oil and soybean oil-based polyol composition, and lignin according to the mass percentage, and stir well to obtain an environmentally friendly coating material; S3, coating implementation: use a brush, roller, or spraying equipment to uniformly apply the mixed coating material to the surface of the wood; S4, drying and curing: place the applied wood at room temperature for natural drying or use an oven to dry at 50-60°C until the surface has no obvious stickiness, and the drying time is 24-48 hours.

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