A waterborne stretch resistant coating composition with modified bio-based fillers, and methods of making and using the same

Abstract

The present application relates to a kind of water-based tensile coating composition with modified bio-based filler and its preparation method and application, including the following weight parts of components: water-based anionic polyurethane 70-85 parts;Deionized water 5-7 parts;Dispersant 1-2 parts;Modified bamboo powder 3-5 parts;Wetting and leveling agent 0.1-0.3 parts;Polyamide wax 1-1.5 parts;pH regulator 0.5-1 parts;Film forming aid 0.5-1 parts;Defoaming agent 0.3-1 parts.Compared with prior art, the present application uses modified bamboo powder, a renewable bio-based material, to replace non-renewable inorganic fillers such as calcium carbonate and talc. After the coating is discarded, it can be naturally degraded without environmental residual pollution. At the same time, deionized water is used as the main solvent, and low VOC film forming aids are used to significantly reduce VOC emissions. The polyurethane synthesis uses environmentally friendly and non-toxic bismuth neodecanoate catalyst to replace highly toxic tin catalysts. From raw materials to the whole preparation process, green environmental protection is achieved, and the coating industry is transformed towards low carbon and sustainability.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an aqueous tensile coating composition using modified bio-based filler as a filler, its preparation method, and its application. Background Technology

[0002] Traditional coatings use petroleum derivatives as core raw materials, resulting in high VOC emissions and significant environmental pollution during production and use. They also rely heavily on non-renewable inorganic fillers such as calcium carbonate, barium sulfate, and talc, which are not only resource-scarce and highly dependent on imports, but also have problems such as limited functionality and limited improvement on paint film performance, making it difficult to meet the needs of new environmental regulations and industrial upgrading.

[0003] Water-based coatings have a clear advantage in terms of environmental protection, but the paint film is usually softer, and its hardness, abrasion resistance, and impact resistance need improvement. Its water resistance and chemical resistance (such as alcohol and detergents) are not as good as solvent-based coatings with high cross-linking degrees. Traditional inorganic fillers (such as calcium carbonate, barium sulfate, and talc) mainly serve to fill and reduce costs, with limited functionality and limited contribution to paint film performance. Excessive addition can even lead to performance degradation, especially affecting the tensile strength and flexibility of the paint film surface. Summary of the Invention

[0004] In view of at least one of the defects of existing water-based coatings, such as insufficient film softness, hardness, wear resistance, impact resistance, and poor surface tensile strength and flexibility, this invention provides a water-based tensile coating composition with modified bio-based materials as fillers, its preparation method and application.

[0005] The objective of this invention can be achieved through the following technical solutions: One objective of this invention is to provide an aqueous tensile coating composition using modified bio-based fillers, characterized by comprising the following components in parts by weight: 70-85 parts of waterborne anionic polyurethane; 5-7 parts deionized water; 1-2 parts dispersant; 3-5 parts of modified bamboo powder; 0.1-0.3 parts of wetting and leveling agent; 1-1.5 parts of polyamide wax; pH adjuster 0.5-1 part; Film-forming aid 0.5-1 part; 0.3-1 part defoamer.

[0006] Furthermore, the aqueous anionic polyurethane comprises the following raw materials in parts by weight: 30-50 parts polybutylene adipate, 20-25 parts toluene diisocyanate, 3-5 parts dimethylolpropionic acid, 1.5-2 parts triethylamine, 2-3 parts ethylenediamine, 0.5-1 parts bismuth neodecanoate, 0.05-0.3 parts acetone, and 40-65 parts deionized water.

[0007] Furthermore, the preparation method of the waterborne anionic polyurethane includes: mixing polybutylene adipate and dimethylolpropionic acid, dehydrating under vacuum until no bubbles are generated; then adding toluene diisocyanate and bismuth neodecanoate under an inert atmosphere to react and obtain a prepolymer; then adding acetone for dilution, adding triethylamine to react until complete, adding deionized water while stirring to form an emulsion, and removing acetone to obtain the waterborne anionic polyurethane.

[0008] Furthermore, the method for preparing the modified bamboo powder includes: mixing dried bamboo powder, silane coupling agent and ethanol aqueous solution evenly, centrifuging after the reaction is complete to obtain a precipitate; washing the precipitate with water until neutral to obtain the modified bamboo powder; The mass of the silane coupling agent is 3-5% of the mass of the dried bamboo powder; the volume ratio of ethanol to water in the ethanol aqueous solution is (100-200): 40.

[0009] Furthermore, the polyamide wax is Desparon AQH-800.

[0010] Furthermore, the film-forming aid comprises ethyl lactate and polyethylene glycol in a mass ratio of (1-4):(1-2), preferably polyethylene glycol with an average molecular weight of 4000.

[0011] Furthermore, the defoamer is BYK-066N and / or Tego Foamex 810.

[0012] The second objective of this invention is to provide a method for preparing an aqueous tensile coating composition with modified bio-based filler as described above, comprising the following steps: after stirring the dispersant, aqueous anionic polyurethane resin, and polyamide wax to a fineness ≤10 micrometers for the first time, adding modified bamboo powder and stirring for the second time to a fineness ≤15 micrometers; then adding deionized water, film-forming aid, and defoamer in sequence, and mixing well to obtain an aqueous tensile coating composition with modified bio-based filler.

[0013] Furthermore, the first stirring speed is 600-800 r / min; the second stirring speed is 1200-1500 r / min.

[0014] The third objective of this invention is the application of a waterborne tensile coating composition with modified bio-based filler as described above in the field of coating.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses modified bamboo powder, a renewable bio-based material, to replace non-renewable inorganic fillers such as calcium carbonate and talc. The coating can be naturally degraded after it is discarded, with no environmental pollution. At the same time, deionized water is used as the main solvent, and low-VOC film-forming aids are used to significantly reduce VOC emissions. In addition, the polyurethane synthesis uses environmentally friendly and non-toxic bismuth neodecanoate catalyst to replace highly toxic tin catalysts. The entire process from raw materials to preparation is green and environmentally friendly, promoting the transformation of the coating industry towards low-carbon and sustainable development.

[0016] (2) This invention removes rigid lignin particles from bamboo powder through chemical modification, which solves the problem that when bamboo powder is used as a filler, the paint film is prone to cracking around the filler and lacks flexibility when impacted. At the same time, the compatibility between modified bamboo powder and water-based anionic polyurethane resin is significantly improved, and it can be evenly dispersed in the resin matrix, giving the paint film excellent tensile strength and flexibility. Even if bending deformation occurs, it is not easy to break, which greatly improves the defects of traditional water-based coatings that are too soft and lack mechanical strength.

[0017] (3) The present invention significantly improves the bonding force between modified bamboo powder and resin matrix, which can eliminate the micropores at the interface between filler and resin, avoid appearance defects such as pinholes and spots in the paint film, and make the coating surface smooth and flat. At the same time, waterborne anionic polyurethane itself has excellent adhesion to ABS and PC substrates. Combined with the synergistic effect of modified bamboo powder, the adhesion of the paint film reaches level 0-1, which is firmly attached and does not fall off, taking into account both aesthetics and practical performance. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0019] One objective of this invention is to provide an aqueous tensile coating composition using modified bio-based fillers, comprising the following components in parts by weight: 70-85 parts of waterborne anionic polyurethane; 5-7 parts deionized water; 1-2 parts dispersant; 3-5 parts of modified bamboo powder; 0.1-0.3 parts of wetting and leveling agent; 1-1.5 parts of polyamide wax; pH adjuster 0.5-1 part; Film-forming aid 0.5-1 part; 0.3-1 part defoamer.

[0020] In this embodiment, the aqueous anionic polyurethane comprises the following raw materials in parts by weight: 30-50 parts polybutylene adipate, 20-25 parts toluene diisocyanate, 3-5 parts dimethylolpropionic acid, 1.5-2 parts triethylamine, 2-3 parts ethylenediamine, 0.5-1 parts bismuth neodecanoate, 0.05-0.3 parts acetone, and 40-65 parts deionized water.

[0021] In this embodiment, the preparation method of the aqueous anionic polyurethane includes: mixing polybutylene adipate and dimethylolpropionic acid, dehydrating under vacuum until no bubbles are generated; then adding toluene diisocyanate and bismuth neodecanoate under an inert atmosphere to react and obtain a prepolymer; then adding acetone for dilution, adding triethylamine to react until complete, adding deionized water while stirring to form an emulsion, and removing acetone to obtain the aqueous anionic polyurethane.

[0022] In this embodiment, the preparation method of the modified bamboo powder includes: mixing dried bamboo powder, silane coupling agent and ethanol aqueous solution evenly, centrifuging after the reaction is complete to obtain a precipitate; washing the precipitate with water until neutral to obtain modified bamboo powder; In this embodiment, the mass of the silane coupling agent is 3-5% of the mass of the dried bamboo powder; the volume ratio of ethanol to water in the ethanol aqueous solution is (100-200): 40.

[0023] In this embodiment, the polyamide wax is Desparon AQH-800.

[0024] In this embodiment, the film-forming aid comprises ethyl lactate and polyethylene glycol in a mass ratio of (1-4):(1-2), preferably polyethylene glycol with an average molecular weight of 4000.

[0025] In this embodiment, the defoamer is BYK-066N and / or Tego Foamex 810.

[0026] The present invention also provides a method for preparing the waterborne tensile coating composition with modified bio-based filler as described above, comprising the following steps: after the dispersant, waterborne anionic polyurethane resin, and polyamide wax are stirred to a fineness ≤10 micrometers for the first time, modified bamboo powder is added and stirred for the second time to a fineness ≤15 micrometers; then deionized water, film-forming aid, and defoamer are added in sequence, and after mixing, the waterborne tensile coating composition with modified bio-based filler is obtained.

[0027] In this embodiment, the first stirring speed is 600-800 r / min; the second stirring speed is 1200-1500 r / min.

[0028] Example 1 (I) This embodiment provides an aqueous tensile coating composition using modified bio-based filler, the coating composition comprising the following components in parts by weight: The aqueous anionic polyurethane comprises the following raw materials in parts by weight: 40 parts polybutylene adipate, 22 parts toluene diisocyanate, 4 parts dimethylolpropionic acid, 1.8 parts triethylamine, 2.5 parts ethylenediamine, 0.8 parts bismuth neodecanoate, 0.15 parts acetone, and 50 parts deionized water. The specific preparation method includes the following steps: According to the formula, polybutylene adipate and dimethylolpropionic acid were put into a clean and dry four-necked flask, stirred and heated to 120°C, and dehydrated under a vacuum of -0.095 MPa for 1 to 2 hours. The system was continuously observed until no bubbles were generated, and the dehydration was completed. Then the reaction system was cooled to 60 to 70°C.

[0029] Under a continuous nitrogen protective atmosphere, a measured amount of toluene diisocyanate and bismuth neodecanoate catalyst were added, and the temperature was slowly increased to 75-85°C at a rate of 1-2°C / min. The reaction was maintained at this temperature for 2-3 hours, and the NCO content was measured to be within ±0.5% of the theoretical value, thus obtaining the prepolymer.

[0030] Cool the prepolymer to 40-50℃, add 50%-100% acetone (total solids), and stir vigorously at 300-500 r / min for 10-15 minutes to dilute the high-viscosity prepolymer into a low-viscosity homogeneous solution.

[0031] Under conditions of 25-40℃, the measured amount of neutralizing agent triethylamine is slowly added dropwise at a rate of 0.5-1 mL / min. After the addition is complete, the reaction is continued at this temperature for 30 minutes to complete the neutralization and salt formation.

[0032] While maintaining high-speed stirring at 800-1200 r / min, metered deionized water is quickly added to the prepolymer acetone solution. Water and acetone quickly become miscible and undergo phase transfer and dispersion to form a stable nanoscale emulsion. Continue to add deionized water to adjust the solid content of the system to 30±1%.

[0033] The resulting emulsion was transferred to a rotary evaporator and rotary evaporated for 1-2 hours at 35-45℃ and -0.09-0.095MPa vacuum to recover most of the acetone solvent in the system. After cooling to room temperature, the material was filtered to obtain the final aqueous anionic polyurethane dispersion.

[0034] (II) This embodiment provides a method for preparing an aqueous tensile coating composition with modified bio-based filler, comprising the following steps: according to the weight parts of the formulation, firstly, the dispersant, aqueous anionic polyurethane resin, and polyamide wax are stirred at 600-800 r / min for 20 min to ensure uniform dispersion. After the fineness is ≤10 micrometers, modified bamboo powder is added under high-speed stirring at 1200-1500 r / min for 25 min until the fineness is ≤15 micrometers. Then, deionized water, film-forming aid, defoamer, and other additives are added sequentially to obtain an aqueous tensile coating prepared with modified bio-based filler.

[0035] Performance test panel preparation: Water-based tensile coating, Covestro Desmodur N3390 and butyl acetate are mixed evenly at a mass ratio of 100:10:60, and then coated on ABS+PC substrate. Flash dry at room temperature for 5-10 minutes; after baking at 80℃ for 1 hour, remove and cool, and perform performance tests after standing at room temperature for 7 days.

[0036] The performance of the paint film obtained in this embodiment was tested, and the results are shown in Table 1 below: Table 1 Comparative Example 1 This comparative example is basically the same as Example 1, except that unmodified bamboo powder was added in this comparative example. The properties of the resulting paint film are shown in Table 2.

[0037] Table 2 Comparative Example 2 This comparative example is basically the same as Example 1, except that no film-forming aid is added in this comparative example. The properties of the obtained paint film are shown in Table 3.

[0038] Table 3 As shown in Tables 1-3, Example 1, using the optimal combination of modified bamboo powder and ethyl lactate-polyethylene glycol film-forming aid, achieved a cross-cut adhesion grade of 0, showed no abnormalities after 240 hours of water resistance at 40℃, had a hardness of H, and passed the tests for impact resistance and flexibility. Its yellowing resistance ΔE = 0.18 was far superior to the standard, and its overall performance fully met the requirements. Comparative Example 1, which only replaced the modified bamboo powder, exhibited poor compatibility between the filler and resin, was hydrophilic and easily absorbed water, and contained components prone to yellowing, resulting in numerous spots on the water-resistant surface, impact cracking, poor flexibility, and poor overall performance. The yellowing ΔE was as high as 2.1, which was seriously exceeded. Only the hardness was close to that of Example 1. In Comparative Example 2, the film-forming aid was removed. Although the water resistance, yellowing resistance and adhesion were basically qualified, the hardness dropped to B, the flexibility was significantly worse, and the impact resistance showed slight cracking. The overall mechanical properties were significantly reduced. The comparison of the three fully proves that modified bamboo powder is the core to ensure water resistance, impact resistance, flexibility and yellowing resistance. The compounded film-forming aid is crucial to maintaining the hardness and toughness of the paint film. The two work together to achieve the optimal balance between environmental protection and mechanical properties in Example 1.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A water-based tensile coating composition using modified bio-based fillers, characterized in that, The components include the following parts by weight: 70-85 parts of waterborne anionic polyurethane; 5-7 parts deionized water; 1-2 parts dispersant; 3-5 parts of modified bamboo powder; 0.1-0.3 parts of wetting and leveling agent; 1-1.5 parts of polyamide wax; pH adjuster 0.5-1 part; Film-forming aid 0.5-1 part; 0.3-1 part defoamer.

2. The aqueous tensile coating composition using modified bio-based filler as described in claim 1, characterized in that, The aqueous anionic polyurethane comprises the following raw materials in parts by weight: 30-50 parts polybutylene adipate, 20-25 parts toluene diisocyanate, 3-5 parts dimethylolpropionic acid, 1.5-2 parts triethylamine, 2-3 parts ethylenediamine, 0.5-1 parts bismuth neodecanoate, 0.05-0.3 parts acetone, and 40-65 parts deionized water.

3. The aqueous tensile coating composition using modified bio-based filler as described in claim 1, characterized in that, The method for preparing the waterborne anionic polyurethane includes: mixing polybutylene adipate and dimethylolpropionic acid, dehydrating under vacuum until no bubbles are generated; then adding toluene diisocyanate and bismuth neodecanoate under an inert atmosphere to react and obtain a prepolymer; then adding acetone for dilution, adding triethylamine to react until complete, adding deionized water while stirring to form an emulsion, and removing acetone to obtain the waterborne anionic polyurethane.

4. The aqueous tensile coating composition using modified bio-based filler as described in claim 1, characterized in that, The method for preparing the modified bamboo powder includes: mixing dried bamboo powder, silane coupling agent and ethanol aqueous solution evenly, centrifuging after the reaction is complete to obtain a precipitate; washing the precipitate with water until neutral to obtain the modified bamboo powder. The mass of the silane coupling agent is 3-5% of the mass of the dried bamboo powder; the volume ratio of ethanol to water in the ethanol aqueous solution is (100-200):

40.

5. The aqueous tensile coating composition using modified bio-based filler as described in claim 1, characterized in that, The polyamide wax mentioned is Desparon AQH-800.

6. The aqueous tensile coating composition using modified bio-based filler as claimed in claim 1, characterized in that, The film-forming aid comprises ethyl lactate and polyethylene glycol in a mass ratio of (1-4):(1-2).

7. The aqueous tensile coating composition using modified bio-based filler as described in claim 1, characterized in that, The defoamer mentioned is BYK-066N and / or Tego Foamex 810.

8. A method for preparing an aqueous tensile coating composition using modified bio-based filler as described in any one of claims 1-7, characterized in that, The process includes the following steps: after the dispersant, waterborne anionic polyurethane resin, and polyamide wax are stirred until the fineness is ≤10 micrometers, modified bamboo powder is added and stirred a second time until the fineness is ≤15 micrometers; then deionized water, film-forming aid, and defoamer are added in sequence, and after mixing, a waterborne tensile coating composition with modified bio-based filler is obtained.

9. The aqueous tensile coating composition using modified bio-based filler as described in claim 8, characterized in that, The first stirring speed is 600-800 r / min; the second stirring speed is 1200-1500 r / min.

10. The application of an aqueous tensile coating composition with modified bio-based filler as described in any one of claims 1-7 in the field of coating.

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