Plant-based polyol eco-friendly coating and preparation method thereof

Abstract

The application discloses a plant-based polyol environment-friendly paint and a preparation method thereof. The paint is prepared from a plant-based polyol resin system, an environment-friendly crosslinking agent, natural fillers and pigments, functional additives and an environment-friendly solvent according to specific weight proportions; wherein the plant-based polyol resin system is a compound of castor oil-based, soybean oil-based, palm oil-based, rosin-based and cashew nut shell oil-based polyols, the environment-friendly crosslinking agent is a bio-based isocyanate, and the functional additives and the solvent are preferably plant-based or bio-based environment-friendly materials. The preparation method comprises four steps of pre-dispersed slurry preparation, filler and pigment grinding and dispersion, paint mixing and aging, and crosslinking and curing, and through accurate control of process parameters such as stirring speed, time and grinding fineness, the stability of product performance is ensured. The paint raw material source is green and environment-friendly, the VOC content is low, and the paint has excellent adhesion, wear resistance and antibacterial and mildew-proof properties, and the preparation process is simple and controllable.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly coatings technology, specifically to a plant-based polyol environmentally friendly coating and its preparation method. Background Technology

[0002] With increasing environmental awareness and stricter policies, the application of traditional petroleum-based coatings is facing increasingly stringent restrictions due to their reliance on non-renewable resources, high content of volatile organic compounds (VOCs), environmental pollution, and harm to human health. Developing green, environmentally friendly, low-VOC, and high-performance coating products has become a development trend in the coating industry.

[0003] Plant-based polyols, as renewable resource-derived materials, possess advantages such as wide availability, environmental friendliness, and good biodegradability, making them ideal raw materials for preparing environmentally friendly coatings as an alternative to petroleum-based polyols. Currently, there are some studies and applications using single plant-based polyols (such as castor oil-based and soybean oil-based) to prepare coatings. However, single plant-based polyols often have performance shortcomings, such as insufficient adhesion, poor abrasion resistance, and slow curing speed, making it difficult to meet the comprehensive performance requirements of coatings in practical applications such as construction, furniture, and industrial coatings. Furthermore, existing plant-based coatings still have shortcomings in the selection of functional additives and optimization of preparation processes, resulting in the need to improve key properties such as product stability, antibacterial and antifungal properties.

[0004] Therefore, how to maintain high bio-based content and low VOCs while simultaneously ensuring coating adhesion, hardness, abrasion resistance, and antibacterial properties is a pressing technical problem that needs to be solved in this field. In summary, developing a plant-based polyol environmentally friendly coating that utilizes a synergistic blend of multiple plant-based polyols, combined with environmentally friendly additives and solvents, and achieves excellent comprehensive performance through optimized preparation processes, has significant practical implications and broad market application prospects. Summary of the Invention

[0005] To address the shortcomings of existing single-plant-based coatings, such as insufficient performance, inadequate environmental friendliness, and imperfect preparation processes, this invention provides a plant-based polyol environmentally friendly coating and its preparation method. By synergistically compounding multiple plant-based polyols, selecting environmentally friendly crosslinking agents, natural fillers and pigments, plant-derived functional additives, and environmentally friendly solvents, and optimizing key process parameters, the invention achieves a balance between the coating's green environmental friendliness and excellent overall performance.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] A plant-based polyol environmentally friendly coating is prepared from the following raw materials in parts by weight:

[0008] Plant-based polyol resin system: 40-60 parts, wherein the plant-based polyol resin system is composed of 15-25 parts castor oil-based polyol, 10-20 parts soybean oil-based polyol, 5-10 parts palm oil-based polyol, 5-10 parts rosin-based polyol, and 5-10 parts cashew nut shell oil-based polyol.

[0009] Environmentally friendly crosslinking agent: 10-20 parts, wherein the environmentally friendly crosslinking agent is a bio-based isocyanate;

[0010] Natural fillers and pigments: 15-30 parts, wherein the natural fillers and pigments are composed of 5-10 parts of nano calcium carbonate, 5-10 parts of modified attapulgite, 3-8 parts of diatomaceous earth, and 2-5 parts of plant carbon black.

[0011] Functional additives: 3-8 parts, wherein the functional additives include 0.5-1.5 parts of plant-derived wetting and dispersing agent, 0.3-0.8 parts of bio-based defoamer, 0.5-1.2 parts of natural leveling agent, 0.5-1.0 parts of plant-derived anti-settling agent, 1.0-2.0 parts of natural antibacterial and antifungal agent, and 0.2-0.5 parts of light stabilizer;

[0012] Environmentally friendly solvent: 10-20 parts, wherein the environmentally friendly solvent is composed of 5-10 parts of bio-based solvent and 5-10 parts of deionized water.

[0013] Preferably, the plant-derived wetting and dispersing agent is a lecithin derivative, the bio-based defoamer is a polysiloxane-polyether composite, the natural leveling agent is a castor oil derivative, the plant-derived antisettling agent is hydrogenated castor oil, the natural antibacterial and antifungal agent is chitosan / cinnamon essential oil microcapsules, and the light stabilizer is a hindered amine.

[0014] Preferably, the bio-based solvent is one or a mixture of two of ethyl lactate and terpineol, and when it is a mixture of two, the weight ratio of ethyl lactate to terpineol is 1:1.

[0015] Preferably, the plant-based polyol resin system comprises 48-55 parts by weight, including 18-22 parts castor oil-based polyol, 12-18 parts soybean oil-based polyol, 6-8 parts palm oil-based polyol, 6-8 parts rosin-based polyol, and 6-8 parts cashew nut shell oil-based polyol.

[0016] Preferably, the natural filler and pigment are in the form of 20-25 parts by weight, including 6-8 parts of nano-calcium carbonate, 6-8 parts of modified attapulgite, 4-6 parts of diatomaceous earth, and 3-4 parts of plant carbon black.

[0017] A method for preparing a plant-based polyol environmentally friendly coating includes the following steps:

[0018] S1. Preparation of pre-dispersed slurry: Under light-protected conditions and low-speed stirring at 300-500 rpm, add the formulated amount of plant-based polyol resin system, the bio-based solvent portion of the environmentally friendly solvent, plant-derived wetting and dispersing agent, plant-derived anti-settling agent and natural antibacterial and antifungal agent sequentially to the dispersion tank, and stir for 10-15 minutes until fully mixed.

[0019] S2. Grinding and dispersing of fillers and pigments: In the mixture obtained in S1, natural fillers and pigments are slowly added, and the rotation speed is gradually increased to 1500-2000 rpm. After high-speed dispersion for 20-30 minutes, the mixture is ground to a fineness of ≤25μm using a sand mill to obtain slurry A.

[0020] S3. Paint mixing and curing: Transfer slurry A to a paint mixing tank, and add bio-based defoamer, natural leveling agent, light stabilizer and remaining environmentally friendly solvent in sequence while stirring at a medium speed of 500-800 rpm. Continue stirring for 15-20 minutes until the system is completely homogeneous.

[0021] S4. Crosslinking and Curing: Before use, slowly add the environmentally friendly crosslinking agent to the mixture obtained in S3, stir at a medium speed of 600-900 rpm for 5-10 minutes until fully mixed, and let stand for 15-30 minutes before application.

[0022] Preferably, the stirring time in step S1 is 12-14 minutes, the high-speed dispersion time in step S2 is 25-28 minutes, the stirring time in step S3 is 16-18 minutes, and the stirring time in step S4 is 7-9 minutes and the maturation time is 20-25 minutes.

[0023] Preferably, in step S2, the grinding media of the sand mill is zirconia beads with a diameter of 0.3-0.8 mm, and the grinding time is 30-60 minutes.

[0024] Preferably, in step S3, the system temperature is controlled at 20-30℃ during stirring, and in step S4, the ripening temperature is controlled at 25-35℃.

[0025] The present invention has the following beneficial effects:

[0026] 1. Excellent environmental performance: The plant-based polyol resin system, bio-based crosslinking agent, natural filler and pigment, plant-derived additives and bio-based solvents in this invention have a high proportion and a high utilization rate of renewable resources. The VOC content of the resulting coating is as low as 28-35g / L, which is far below the national standard limit. It is environmentally friendly and meets the requirements of environmental protection policies.

[0027] 2. Outstanding Comprehensive Performance: Through the synergistic blending of castor oil-based, soybean oil-based, palm oil-based, rosin-based, and cashew nut shell oil-based polyols, the coating film balances flexibility, hardness, heat resistance, and abrasion resistance. Combined with natural fillers and pigments such as nano-calcium carbonate, modified attapulgite clay, diatomaceous earth, and plant carbon black, as well as natural antibacterial and antifungal agents such as chitosan / cinnamon essential oil microcapsules and hindered amine light stabilizers, the coating exhibits excellent adhesion, abrasion resistance, pencil hardness, weather resistance, and antibacterial and antifungal properties, meeting the coating needs of various application scenarios such as construction, furniture, and industrial equipment.

[0028] 3. Simple and controllable preparation process: The preparation process of this invention does not require complex equipment and can be achieved using only conventional dispersion, grinding, and paint mixing equipment. By limiting key process parameters such as the type and particle size of the grinding media, stirring speed, grinding fineness, and temperature, the dispersibility and storage stability of the system are significantly improved. The process is simple to operate, has good reproducibility, and is easy to realize for large-scale continuous industrial production, showing good prospects for industrialization and promotion. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a plant-based polyol environmentally friendly coating, prepared from the following raw materials in parts by weight:

[0031] Plant-based polyol resin system (40-60 parts)

[0032] This compound is formulated with castor oil-based polyols (15-25 parts), soybean oil-based polyols (10-20 parts), palm oil-based polyols (5-10 parts), rosin-based polyols (5-10 parts), and cashew nut shell oil-based polyols (5-10 parts). This compound system leverages the performance advantages of each plant-based polyol: castor oil-based polyols offer good flexibility and adhesion; soybean oil-based polyols are cost-effective and widely available; palm oil-based polyols exhibit excellent heat resistance; rosin-based polyols improve coating hardness; and cashew nut shell oil-based polyols enhance abrasion resistance. Through synergistic effects, the overall performance of the coating is improved.

[0033] Preferably, the plant-based polyol resin system comprises 48-55 parts by weight, including 18-22 parts castor oil-based polyol, 12-18 parts soybean oil-based polyol, 6-8 parts palm oil-based polyol, 6-8 parts rosin-based polyol, and 6-8 parts cashew nut shell oil-based polyol. This ratio provides the best balance between the flexibility and hardness of the coating.

[0034] The environmentally friendly crosslinking agent (10-20 parts) is a bio-based isocyanate, which undergoes a crosslinking reaction with the plant-based polyol resin system to form a three-dimensional network structure, improving the curing speed and mechanical properties of the coating. Moreover, its bio-based origin makes it more environmentally friendly.

[0035] The natural filler and pigment (15-30 parts) consists of nano-calcium carbonate (5-10 parts), modified attapulgite (5-10 parts), diatomaceous earth (3-8 parts), and plant carbon black (2-5 parts). Nano-calcium carbonate improves the hardness and abrasion resistance of the coating, modified attapulgite enhances the stability and adhesion of the system, diatomaceous earth has adsorption and breathability, and plant carbon black, as a pigment, has both light-blocking and environmentally friendly properties. The components work synergistically to improve the physical properties and decorative effect of the coating.

[0036] Preferably, the weight ratio of natural fillers and pigments is 20-25 parts, including 6-8 parts of nano-calcium carbonate, 6-8 parts of modified attapulgite, 4-6 parts of diatomaceous earth, and 3-4 parts of plant carbon black. This ratio can optimize the filling properties and color uniformity of the coating.

[0037] Functional additives (3-8 parts)

[0038] Plant-derived wetting and dispersing agent (0.5-1.5 parts): Lecithin derivatives are selected to improve the uniformity of raw material dispersion and avoid agglomeration;

[0039] Bio-based defoamer (0.3-0.8 parts): Polysiloxane-polyether composite type, effectively eliminates bubbles generated during the preparation process, ensuring the smoothness of the coating;

[0040] Natural leveling agent (0.5-1.2 parts): Castor oil derivative, improves the leveling properties of paint application and reduces brush marks;

[0041] Plant-derived anti-settling agent (0.5-1.0 parts): hydrogenated castor oil, to prevent fillers and pigments from settling and improve the storage stability of coatings;

[0042] Natural antibacterial and antifungal agent (1.0-2.0 parts): Chitosan / cinnamon essential oil microcapsules. Chitosan and cinnamon essential oil work synergistically to achieve long-lasting antibacterial and antifungal effects. It is also naturally derived, non-toxic and harmless.

[0043] Light stabilizer (0.2-0.5 parts): Hindered amines, which improve the weather resistance of coatings and delay aging.

[0044] Environmentally friendly solvent (10-20 parts)

[0045] Composed of a bio-based solvent (5-10 parts) and deionized water (5-10 parts), this product replaces traditional organic solvents and significantly reduces VOC content. The bio-based solvent is one or a mixture of two of ethyl lactate and terpineol. When two are mixed, the weight ratio of ethyl lactate to terpineol is 1:1. This combination of solvents has the best matching degree of solubility and volatility, which can effectively ensure the smoothness of coating application.

[0046] This invention provides a method for preparing a plant-based polyol environmentally friendly coating, comprising the following steps:

[0047] S1. Preparation of pre-dispersed slurry: Under light-protected conditions (to avoid degradation of some components due to light exposure), set the speed of the dispersion tank to 300-500 rpm (low-speed stirring to prevent the generation of bubbles), and add the plant-based polyol resin system, bio-based solvent, plant-derived wetting and dispersing agent, plant-derived anti-settling agent and natural antibacterial and antifungal agent in sequence, and stir for 10-15 minutes (preferably 12-14 minutes) to ensure that all components are fully mixed and form a uniform pre-dispersed slurry.

[0048] S2. Grinding and Dispersion of Fillers and Pigments: Slowly add natural fillers and pigments to the pre-dispersed slurry (to avoid agglomeration), gradually increasing the rotation speed to 1500-2000 rpm (high-speed dispersion breaks up agglomerates). After dispersing for 20-30 minutes (preferably 25-28 minutes), grind to a fineness ≤25μm using a sand mill (to ensure coating smoothness and adhesion). The grinding media in the sand mill are zirconia beads with a diameter of 0.3-0.8 mm, and the grinding time is 30-60 minutes. This parameter setting efficiently achieves ultra-fine dispersion of fillers and pigments, yielding slurry A.

[0049] S3. Paint Mixing and Curing: Transfer slurry A to the paint mixing tank and set the speed to 500-800 rpm (medium-speed stirring ensures uniform mixing and prevents the formation of bubbles). During stirring, control the system temperature at 20-30℃ (avoid high temperature affecting the performance of additives). Add bio-based defoamer, natural leveling agent, light stabilizer, and deionized water in sequence, and stir for 15-20 minutes (preferably 16-18 minutes) to make the system completely uniform and achieve the adjustment of coating performance.

[0050] S4. Crosslinking and Curing: Before use, crosslink the material (to avoid premature curing affecting construction). Slowly add the bio-based isocyanate to the mixed paint and stir at a medium speed of 600-900 rpm for 5-10 minutes (preferably 7-9 minutes to ensure uniform dispersion of the crosslinking agent). Let it stand and mature for 15-30 minutes (preferably 20-25 minutes). The maturation temperature should be controlled at 25-35℃ (to promote full crosslinking reaction). Then it is ready for construction and application.

[0051] Example 1

[0052] A plant-based polyol environmentally friendly coating, the raw materials are as follows by weight:

[0053] Plant-based polyol resin system: 48 parts (18 parts castor oil-based polyol, 12 parts soybean oil-based polyol, 6 parts palm oil-based polyol, 6 parts rosin-based polyol, 6 parts cashew nut shell oil-based polyol);

[0054] Environmentally friendly crosslinking agent (bio-based isocyanate): 12 parts;

[0055] Natural fillers and pigments: 19 parts (6 parts nano calcium carbonate, 6 parts modified attapulgite, 4 parts diatomaceous earth, 3 parts plant carbon black).

[0056] Functional additives: 3.9 parts (0.8 parts lecithin derivative, 0.4 parts polysiloxane-polyether composite defoamer, 0.6 parts castor oil derivative, 0.6 parts hydrogenated castor oil, 1.2 parts chitosan / cinnamon essential oil microcapsules, 0.3 parts hindered amine light stabilizer);

[0057] Environmentally friendly solvent: 12 parts (3 parts ethyl lactate, 3 parts terpineol, 6 parts deionized water).

[0058] Preparation method:

[0059] S1. Preparation of pre-dispersed slurry: Under light-protected conditions, the dispersion tank is rotated at 350 rpm. The above-mentioned plant-based polyol resin system, ethyl lactate, terpineol, lecithin derivative, hydrogenated castor oil and chitosan / cinnamon essential oil microcapsules are added in sequence and stirred for 12 minutes until they are mixed evenly.

[0060] S2. Grinding and dispersing of fillers and pigments: Natural fillers and pigments are slowly added, and the rotation speed is gradually increased to 1600 rpm. After high-speed dispersion for 25 minutes, zirconia beads with a diameter of 0.5 mm are used as grinding media and the mixture is ground in a sand mill for 40 minutes to a fineness of 20 μm to obtain slurry A.

[0061] S3. Paint mixing and curing: Transfer slurry A to the paint mixing kettle, rotate at 600 rpm, control the system temperature at 25℃, and add polysiloxane-polyether composite defoamer, castor oil derivative, hindered amine light stabilizer and deionized water in sequence, and stir for 16 minutes until the system is uniform.

[0062] S4. Crosslinking and curing: Add bio-based isocyanate before use, stir at 700 rpm for 7 minutes, let stand at 28℃ for 20 minutes to mature, and then it is ready for construction.

[0063] Example 2

[0064] A plant-based polyol environmentally friendly coating, the raw materials are as follows by weight:

[0065] Plant-based polyol resin system: 58 parts (20 parts castor oil-based polyol, 15 parts soybean oil-based polyol, 7 parts palm oil-based polyol, 8 parts rosin-based polyol, 8 parts cashew nut shell oil-based polyol);

[0066] Environmentally friendly crosslinking agent (bio-based isocyanate): 15 parts;

[0067] Natural fillers and pigments: 22 parts (7 parts nano calcium carbonate, 7 parts modified attapulgite, 5 parts diatomaceous earth, 3 parts plant carbon black);

[0068] Functional additives: 4.8 parts (1.0 part of lecithin derivative, 0.5 parts of polysiloxane-polyether composite defoamer, 0.8 parts of castor oil derivative, 0.7 parts of hydrogenated castor oil, 1.5 parts of chitosan / cinnamon essential oil microcapsules, and 0.3 parts of hindered amine light stabilizer);

[0069] Environmentally friendly solvent: 15 parts (7 parts terpineol, 8 parts deionized water).

[0070] Preparation method:

[0071] S1. Preparation of pre-dispersed slurry: Under light-protected conditions, the dispersion tank is rotated at 400 rpm. The above-mentioned plant-based polyol resin system, terpineol, lecithin derivative, hydrogenated castor oil and chitosan / cinnamon essential oil microcapsules are added in sequence and stirred for 13 minutes until the mixture is uniform.

[0072] S2. Grinding and dispersing of fillers and pigments: Natural fillers and pigments were slowly added, and the rotation speed was gradually increased to 1800 rpm. After high-speed dispersion for 26 minutes, zirconia beads with a diameter of 0.6 mm were used as grinding media and the mixture was ground in a sand mill for 45 minutes to a fineness of 19 μm to obtain slurry A.

[0073] S3. Paint mixing and curing: Transfer slurry A to the paint mixing kettle, rotate at 650 rpm, control the system temperature at 26℃, add bio-based defoamer, natural leveling agent, light stabilizer and deionized water in sequence, and stir for 17 minutes until the system is uniform.

[0074] S4. Crosslinking and curing: Add bio-based isocyanate before use, stir at 750 rpm for 8 minutes, and let stand at 30°C for 22 minutes to mature before application.

[0075] Example 3

[0076] A plant-based polyol environmentally friendly coating, the raw materials are as follows by weight:

[0077] Plant-based polyol resin system: 64 parts (22 parts castor oil-based polyol, 18 parts soybean oil-based polyol, 8 parts palm oil-based polyol, 8 parts rosin-based polyol, 8 parts cashew nut shell oil-based polyol);

[0078] Environmentally friendly crosslinking agent (bio-based isocyanate): 18 parts;

[0079] Natural fillers and pigments: 26 parts (8 parts nano calcium carbonate, 8 parts modified attapulgite, 6 parts diatomaceous earth, 4 parts plant carbon black).

[0080] Functional additives: 5.9 parts (1.2 parts lecithin derivative, 0.7 parts polysiloxane-polyether composite defoamer, 1.0 part castor oil derivative, 0.8 parts hydrogenated castor oil, 1.8 parts chitosan / cinnamon essential oil microcapsules, 0.4 parts hindered amine light stabilizer);

[0081] Environmentally friendly solvent: 18 parts (5 parts ethyl lactate, 4 parts terpineol, 9 parts deionized water).

[0082] Preparation method:

[0083] S1. Preparation of pre-dispersed slurry: Under light-protected conditions, the dispersion tank is rotated at 450 rpm. The above-mentioned plant-based polyol resin system, ethyl lactate, terpineol, lecithin derivative, hydrogenated castor oil and chitosan / cinnamon essential oil microcapsules are added in sequence and stirred for 14 minutes until they are mixed evenly.

[0084] S2. Grinding and dispersing of fillers and pigments: Natural fillers and pigments were slowly added, and the rotation speed was gradually increased to 1900 rpm. After high-speed dispersion for 28 minutes, zirconia beads with a diameter of 0.7 mm were used as grinding media and the mixture was ground in a sand mill for 50 minutes to a fineness of 18 μm to obtain slurry A.

[0085] S3. Paint mixing and curing: Transfer slurry A to the paint mixing kettle, rotate at 750 rpm, control the system temperature at 28℃, add bio-based defoamer, natural leveling agent, light stabilizer and deionized water in sequence, and stir for 18 minutes until the system is uniform.

[0086] S4. Crosslinking and curing: Add bio-based isocyanate before use, stir at 850 rpm for 9 minutes, let stand at 32℃ for 25 minutes to mature, and then it is ready for construction.

[0087] Example 4

[0088] A plant-based polyol environmentally friendly coating, the raw materials are as follows by weight:

[0089] Plant-based polyol resin system: 58 parts (21 parts castor oil-based polyol, 16 parts soybean oil-based polyol, 7 parts palm oil-based polyol, 7 parts rosin-based polyol, 7 parts cashew nut shell oil-based polyol);

[0090] Environmentally friendly crosslinking agent (bio-based isocyanate): 16 parts;

[0091] Natural fillers and pigments: 23 parts (7 parts nano-calcium carbonate, 7 parts modified attapulgite, 5 parts diatomaceous earth, 4 parts plant carbon black);

[0092] Functional additives: 5.2 parts (1.1 parts lecithin derivative, 0.6 parts polysiloxane-polyether composite defoamer, 0.9 parts castor oil derivative, 0.7 parts hydrogenated castor oil, 1.6 parts chitosan / cinnamon essential oil microcapsules, 0.3 parts hindered amine light stabilizer);

[0093] Environmentally friendly solvent: 16 parts (4 parts ethyl lactate, 4 parts terpineol, 8 parts deionized water).

[0094] Preparation method:

[0095] S1. Preparation of pre-dispersed slurry: Under light-protected conditions, the dispersion tank is rotated at 420 rpm. The above-mentioned plant-based polyol resin system, ethyl lactate, terpineol, lecithin derivative, hydrogenated castor oil and chitosan / cinnamon essential oil microcapsules are added in sequence and stirred for 13 minutes until they are evenly mixed.

[0096] S2. Grinding and dispersing of fillers and pigments: Natural fillers and pigments were slowly added, and the rotation speed was gradually increased to 1700 rpm. After high-speed dispersion for 27 minutes, zirconia beads with a diameter of 0.6 mm were used as grinding media and the mixture was ground in a sand mill for 42 minutes to a fineness of 19 μm to obtain slurry A.

[0097] S3. Paint mixing and curing: Transfer slurry A to the paint mixing kettle, rotate at 700 rpm, control the system temperature at 27℃, and add polysiloxane-polyether composite defoamer, castor oil derivative, hindered amine light stabilizer and deionized water in sequence, and stir for 17 minutes until the system is uniform.

[0098] S4. Crosslinking and curing: Add bio-based isocyanate before use, stir at 800 rpm for 8 minutes, let stand at 30℃ for 23 minutes to mature, and then it is ready for construction.

[0099] Example 5

[0100] A plant-based polyol environmentally friendly coating, the raw materials are as follows by weight:

[0101] Plant-based polyol resin system: 62 parts (22 parts castor oil-based polyol, 17 parts soybean oil-based polyol, 8 parts palm oil-based polyol, 7 parts rosin-based polyol, and 8 parts cashew nut shell oil-based polyol).

[0102] Environmentally friendly crosslinking agent (bio-based isocyanate): 17 parts;

[0103] Natural fillers and pigments: 24 parts (8 parts nano calcium carbonate, 7 parts modified attapulgite, 6 parts diatomaceous earth, 3 parts plant carbon black);

[0104] Functional additives: 5.7 parts (1.2 parts lecithin derivative, 0.7 parts polysiloxane-polyether composite defoamer, 1.0 part castor oil derivative, 0.8 parts hydrogenated castor oil, 1.7 parts chitosan / cinnamon essential oil microcapsules, 0.3 parts hindered amine light stabilizer);

[0105] Environmentally friendly solvent: 17 parts (5 parts ethyl lactate, 3 parts terpineol, 9 parts deionized water).

[0106] Preparation method:

[0107] S1. Preparation of pre-dispersion slurry: Under light-protected conditions, the dispersion tank is rotated at 440 rpm. The above-mentioned plant-based polyol resin system, ethyl lactate, terpineol, lecithin derivative, hydrogenated castor oil and chitosan / cinnamon essential oil microcapsules are added in sequence and stirred for 14 minutes until they are mixed evenly.

[0108] S2. Grinding and dispersing of fillers and pigments: Natural fillers and pigments were slowly added, and the rotation speed was gradually increased to 1850 rpm. After high-speed dispersion for 28 minutes, zirconia beads with a diameter of 0.7 mm were used as grinding media and the mixture was ground in a sand mill for 48 minutes to a fineness of 18 μm to obtain slurry A.

[0109] S3. Paint mixing and curing: Transfer slurry A to the paint mixing kettle, rotate at 720 rpm, control the system temperature at 29℃, and add polysiloxane-polyether composite defoamer, castor oil derivative, hindered amine light stabilizer and deionized water in sequence, and stir for 18 minutes until the system is uniform.

[0110] S4. Crosslinking and curing: Add bio-based isocyanate before use, stir at 820 rpm for 9 minutes, and let stand at 31℃ for 24 minutes before application.

[0111] Comparative Example 1 (Single Plant-Based Polyol System)

[0112] The raw material weight parts and preparation method are basically the same as in Example 2. The only difference is that the plant-based polyol resin system is replaced with 50 parts of single castor oil-based polyol, without soybean oil-based, palm oil-based, rosin-based and cashew nut shell oil-based polyols.

[0113] Comparative Example 2 (Traditional Petroleum-Based Additives and Solvents)

[0114] The raw material weight parts and preparation method are basically the same as in Example 2, the only difference being that: the functional additives are replaced with 1.0 part of petroleum-based wetting and dispersing agent, 0.5 part of mineral oil defoamer, 0.8 part of synthetic resin leveling agent, 0.7 part of organic bentonite antisettling agent, and 1.5 part of chemically synthesized antibacterial agent; the environmentally friendly solvent is replaced with 7 parts of butyl acetate and 8 parts of deionized water.

[0115] Comparative Example 3 (Simplified Preparation Process)

[0116] The raw material weight parts are basically the same as in Example 2. The difference in preparation method is that the high-speed dispersion time in step S2 is shortened to 10 minutes and the grinding fineness of the sand mill is controlled at 35μm; the stirring time in step S4 is shortened to 3 minutes and the maturation time is shortened to 5 minutes.

[0117] Performance Tests and Results

[0118] The coatings prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to performance tests according to the following test methods. The test results are shown in Table 1.

[0119] 1. GB / T 1725-2007 "Determination of Non-volatile Content in Paints, Varnishes and Plastics" The core of this method is to completely evaporate the volatile components (such as solvents and water) in the sample by heating. The percentage of the mass of the remaining non-volatile components (resin, pigment, filler, additives, etc.) relative to the mass of the original sample is the "non-volatile content".

[0120] 2. GB / T 9286-2021 "Cross-cut Test for Paints and Varnishes" describes a method that uses a specialized cutting tool with multiple parallel cutting edges to cut mutually perpendicular grid patterns at specified intervals on the coating surface. This process artificially creates weak areas and stress concentration points within the coating. Subsequently, adhesive tape is applied and quickly peeled off the grid area. The adhesion strength between the coating and the substrate, or between different layers of the coating, is qualitatively determined by examining and evaluating the quantity and morphology of the coating peeling off from the grid.

[0121] 3. GB / T 6739-2022 "Determination of Hardness of Paints and Varnishes by Pencil Method" The principle of this method is to simulate the scratching behavior of hard objects (such as keys, fingernails, and other objects) on the coating surface in daily life. By using a series of standard drawing pencils of known hardness (from the softest 6B to the hardest 9H) as scratching tools, the "scratch hardness" or "pencil hardness" of the paint film is qualitatively evaluated by advancing them at a specific angle on the paint film surface under a fixed load.

[0122] 4. GB / T 1768-2006 Determination of Abrasion Resistance of Paints and Varnishes by Rotating Rubber Grinding Wheel Method. This method aims to simulate and accelerate the wear phenomenon of coatings in real environment due to repeated friction and scratching (such as people walking, objects being dragged, cleaning and wiping, etc.).

[0123] 5. GB / T 21866-2008 "Determination of Antibacterial Properties and Antibacterial Effects of Antibacterial Coatings (Films)" This method involves quantitatively inoculating bacteria onto a sample to be tested, using a film to ensure uniform contact of the bacteria with the sample, and after a certain period of incubation, detecting the number of viable bacteria in the sample and calculating the antibacterial rate of the sample.

[0124] 6. GB / T 1741-2020 "Determination of Antifungal Resistance of Paint Films" This test method simulates the environmental conditions for mold growth in nature and designs an accelerated test based on the physiological characteristics of mold growth. Mold spores are inoculated onto the sample surface, and then the sample is placed in an environment suitable for mold growth to observe the growth of mold on the sample surface. The antifungal resistance of the paint film is evaluated and graded based on the degree of mold growth on the sample surface.

[0125] Table 1

[0126]

[0127] Data Analysis

[0128] 1. Performance Consistency and Optimization Trend Analysis of Implementation Examples

[0129] Test data from Examples 1-5 show that all performance indicators of the examples are superior to the requirements of national standards, demonstrating the stability of the formulation and process of this invention. Looking at the data trends, as the proportions of each component in the plant-based polyol resin system approach the median of the optimal range (e.g., 22 parts castor oil-based polyol and 17-18 parts soybean oil-based polyol in Examples 3 and 5), and with the reasonable increase in the amount of environmentally friendly crosslinking agent and natural filler, the overall performance of the coating shows a gradual optimization trend: VOC content decreased from 33 g / L to 28 g / L, adhesion improved from grade 1 to grade 0, abrasion resistance weight loss decreased from 0.025 to 0.018, and antibacterial rate increased from 99.2% to 99.8%. This indicates that the synergistic effect of the multi-component plant-based polyols is more significant after the formulation optimization. Simultaneously, the increased amount of crosslinking agent and filler helps to form a denser coating structure, improving mechanical properties and environmental friendliness.

[0130] 2. Comparative Analysis of Comparative Examples and Implementation Examples

[0131] (1) Defects of single plant-based polyols: Comparative Example 1 used a single castor oil-based polyol to replace the compound system. Although the VOC content was still low (35g / L), the adhesion dropped to level 2, the pencil hardness was only level B, the abrasion resistance weight loss was as high as 0.028, far exceeding the national standard limit, and the mildew resistance level also dropped to level 1. Comparative Example 2 shows that the multi-component compound system significantly compensated for the performance shortcomings of single plant-based polyols through the synergistic effects of the flexibility of castor oil, the hardness improvement of rosin, and the abrasion resistance enhancement of cashew nut shell oil. This proves that multi-component compounding is the core innovation point for achieving the comprehensive performance standard of coatings.

[0132] (2) Environmental and functional disadvantages of petroleum-based components: Comparative Example 2 used traditional petroleum-based additives and solvents, and the VOC content soared to 85 g / L. Although it did not exceed the national standard limit, it was nearly 1.66 times higher than the 32 g / L of Example 2, and the environmental performance was greatly reduced. At the same time, the antibacterial rate of the chemically synthesized antibacterial agent was only 82%, which did not meet the national standard requirements, and the anti-mildew level dropped to level 2. This shows that plant-derived additives (such as chitosan / cinnamon essential oil microcapsules) have unique advantages in antibacterial and anti-mildew performance, and bio-based solvents are the key guarantee for achieving low VOC.

[0133] (3) Importance of process parameters: In Comparative Example 3, the simplified preparation process resulted in insufficient high-speed dispersion time, coarse grinding fineness, and excessively short cross-linking stirring and curing time, leading to a drop in adhesion to grade 2, a decrease in pencil hardness to grade H, and a wear resistance weight loss of 11 mg, exceeding the national standard. As can be seen from Comparative Example 2, optimized process parameters (such as high-speed dispersion for 25-28 minutes, grinding fineness ≤25μm, and cross-linking stirring for 7-9 minutes) can ensure sufficient dispersion of raw materials and complete cross-linking reaction, avoiding voids in the coating film and thus ensuring stable performance.

[0134] 3. Core Conclusions

[0135] This invention achieves a balance between environmental friendliness and overall performance in coatings through triple innovation: the blending of multiple plant-based polyols, the selection of environmentally friendly components, and the optimization of the preparation process. Example data demonstrates that when the plant-based polyol resin system is blended at 45-55 parts, the environmentally friendly crosslinking agent at 10-20 parts, and the natural filler at 20-25 parts, with strict control of the grinding fineness ≤25μm and the crosslinking curing time at 20-25 minutes, the coating exhibits optimal performance. This meets the usage requirements of applications such as construction and furniture making, while also complying with environmental protection policies, demonstrating significant advantages over existing technologies.

[0136] The examples provided in this invention are not intended to limit the implementation. Those skilled in the art will recognize that various variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, and any obvious variations or modifications derived therefrom are still within the scope of this invention.

Claims

1. A plant-based polyol environmentally friendly coating, characterized in that, It is prepared from the following raw materials in parts by weight: Plant-based polyol resin system: 40-60 parts, wherein the plant-based polyol resin system is composed of 15-25 parts castor oil-based polyol, 10-20 parts soybean oil-based polyol, 5-10 parts palm oil-based polyol, 5-10 parts rosin-based polyol, and 5-10 parts cashew nut shell oil-based polyol. Environmentally friendly crosslinking agent: 10-20 parts, wherein the environmentally friendly crosslinking agent is a bio-based isocyanate; Natural fillers and pigments: 15-30 parts, wherein the natural fillers and pigments are composed of 5-10 parts of nano calcium carbonate, 5-10 parts of modified attapulgite, 3-8 parts of diatomaceous earth, and 2-5 parts of plant carbon black. Functional additives: 3-8 parts, wherein the functional additives include 0.5-1.5 parts of plant-derived wetting and dispersing agent, 0.3-0.8 parts of bio-based defoamer, 0.5-1.2 parts of natural leveling agent, 0.5-1.0 parts of plant-derived anti-settling agent, 1.0-2.0 parts of natural antibacterial and antifungal agent, and 0.2-0.5 parts of light stabilizer; Environmentally friendly solvent: 10-20 parts, wherein the environmentally friendly solvent is composed of 5-10 parts of bio-based solvent and 5-10 parts of deionized water; The plant-derived wetting and dispersing agent is a lecithin derivative, the bio-based defoamer is a polysiloxane-polyether composite, the natural leveling agent is a castor oil derivative, the plant-derived antisettling agent is hydrogenated castor oil, the natural antibacterial and antifungal agent is chitosan / cinnamon essential oil microcapsules, and the light stabilizer is a hindered amine. The bio-based solvent is one or a mixture of two of ethyl lactate and terpineol. When it is a mixture of two, the weight ratio of ethyl lactate to terpineol is 1:

1.

2. The plant-based polyol environmentally friendly coating according to claim 1, characterized in that, The plant-based polyol resin system comprises 48-55 parts by weight, including 18-22 parts castor oil-based polyol, 12-18 parts soybean oil-based polyol, 6-8 parts palm oil-based polyol, 6-8 parts rosin-based polyol, and 6-8 parts cashew nut shell oil-based polyol.

3. The plant-based polyol environmentally friendly coating according to claim 1, characterized in that, The natural filler and pigment are in the form of 20-25 parts by weight, including 6-8 parts of nano-calcium carbonate, 6-8 parts of modified attapulgite, 4-6 parts of diatomaceous earth, and 3-4 parts of plant carbon black.

4. A method for preparing a plant-based polyol environmentally friendly coating as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of pre-dispersed slurry: Under light-protected conditions and low-speed stirring at 300-500 rpm, add the formulated amount of plant-based polyol resin system, the bio-based solvent portion of the environmentally friendly solvent, plant-derived wetting and dispersing agent, plant-derived anti-settling agent and natural antibacterial and antifungal agent sequentially to the dispersion tank, and stir for 10-15 minutes until fully mixed. S2. Grinding and dispersing of fillers and pigments: In the mixture obtained in S1, natural fillers and pigments are slowly added, and the rotation speed is gradually increased to 1500-2000 rpm. After high-speed dispersion for 20-30 minutes, the mixture is ground to a fineness of ≤25μm using a sand mill to obtain slurry A. S3. Paint mixing and curing: Transfer slurry A to a paint mixing tank, and add bio-based defoamer, natural leveling agent, light stabilizer and remaining environmentally friendly solvent in sequence while stirring at a medium speed of 500-800 rpm. Continue stirring for 15-20 minutes until the system is completely homogeneous. S4. Crosslinking and Curing: Before use, slowly add the environmentally friendly crosslinking agent to the mixture obtained in S3, stir at a medium speed of 600-900 rpm for 5-10 minutes until fully mixed, and let stand for 15-30 minutes before application.

5. The method for preparing a plant-based polyol environmentally friendly coating according to claim 4, characterized in that, The stirring time in step S1 is 12-14 minutes, the high-speed dispersion time in step S2 is 25-28 minutes, the stirring time in step S3 is 16-18 minutes, and the stirring time in step S4 is 7-9 minutes and the maturation time is 20-25 minutes.

6. The method for preparing a plant-based polyol environmentally friendly coating according to claim 4, characterized in that, In step S2, the grinding media of the sand mill is zirconia beads with a diameter of 0.3-0.8 mm, and the grinding time is 30-60 minutes.

7. The method for preparing a plant-based polyol environmentally friendly coating according to claim 4, characterized in that, In step S3, the system temperature is controlled at 20-30℃ during stirring. In step S4, the ripening temperature is controlled at 25-35℃.

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