A bio-based coating and a preparation method and application thereof

Abstract

The application discloses a kind of bio-based coating and its preparation method and application, including the following mass parts of raw materials: plant oil modified cellulose ether 0.2-1 part, filler 20-40 parts, pigment 5-15 parts, auxiliary 0.5-2.5 parts, bio-based emulsion 20-40 parts, water 20-40 parts.The bio-based coating of the application uses a new type of bio-based emulsion, which can widen the glass transition temperature, and the film-forming temperature is lower, so that the prepared paint film has good film-forming property and low-temperature stability; cellulose ether uses plant oil modified nanocellulose, compared with traditional cellulose ether, its slender structure and hydrophilic and lipophilic end structure can further improve the washability and stain resistance of the coating.The bio-based coating prepared by the application has the characteristics of strong washability and strong stain resistance in performance compared with existing coatings, and can be applied in the field of interior wall coating.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a bio-based coating, its preparation method, and its application. Background Technology

[0002] With increasing awareness of environmental protection, green and environmentally friendly water-based coatings have become an important part of the coating market. Water-based coatings replace organic solvents with water, avoiding the volatile organic compound pollution produced by solvent-based coatings. Traditional water-based coatings mainly use non-renewable resources such as petroleum as raw materials for emulsion synthesis. Currently, research is being conducted to use biomass resources such as plant biomass resources and renewable waste resources as raw materials to produce new biomass emulsions. However, bio-based coatings made from current biomass emulsions have defects such as poor low-temperature stability, poor film-forming properties, and insufficient washability and stain resistance. Further addition of film-forming aids and freeze-thaw resistance aids is needed, but the defects of insufficient washability and stain resistance of the paint film urgently need to be solved. Summary of the Invention

[0003] To overcome the problems existing in the prior art, one objective of this invention is to provide a bio-based coating. A second objective is to provide a method for preparing the aforementioned bio-based coating. A third objective is to provide applications of the aforementioned bio-based coating. This invention primarily addresses the problems of poor storage stability, poor film-forming properties, and insufficient scrub and stain resistance in existing bio-based coatings. By using a novel bio-based emulsion with good stability and low film-forming temperature in the coating formulation, and adding modified nanocellulose ether, film-forming aids and antifreeze-thaw agents are eliminated, effectively reducing the use of volatile organic compounds (VOCs) and resulting in a bio-based coating with high stability, strong film-forming properties, high scrub resistance, and high stain resistance.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] The first aspect of the present invention provides a bio-based coating comprising the following raw materials in parts by weight: 0.2-1 parts of vegetable oil modified cellulose ether, 20-40 parts of filler, 5-15 parts of pigment, 0.5-2.5 parts of additives, 20-40 parts of bio-based emulsion, and 20-40 parts of water.

[0006] Preferably, the vegetable oil-modified cellulose ether is prepared by a method comprising the following steps:

[0007] S1. Biomass raw materials are mixed with cellulase and reacted. The reaction product is then inactivated and ground to obtain nanocellulose.

[0008] S2. The nanocellulose is alkalized and etherified to obtain nanocellulose ether;

[0009] S3. The nanocellulose ether is reacted with vegetable oil and bromoalkane to obtain vegetable oil modified cellulose ether.

[0010] More preferably, in step S1, the biomass raw material is selected from wood pulp or bamboo pulp.

[0011] More preferably, in step S1, the cellulase is selected from one or more of 1,4-β-D-endoglucanase, 1,4-β-D-exoglucanase, and β-glucosidase. More preferably, the cellulase is selected from 1,4-β-D-endoglucanase and 1,4-β-D-exoglucanase. Even more preferably, the mass ratio of the 1,4-β-D-endoglucanase to the 1,4-β-D-exoglucanase is 1:(0.7-1.5).

[0012] More preferably, in step S1, the ratio of cellulase activity to the mass of biomass raw material is (100-500) U: 1g. Even more preferably, the ratio of cellulase activity to the mass of biomass raw material is (100-300) U: 1g.

[0013] More preferably, in step S1, the reaction temperature is 40-60°C and the reaction time is 3-5 hours. Even more preferably, the reaction temperature is 45-55°C and the reaction time is 3.5-4.5 hours.

[0014] More preferably, in step S1, the inactivation temperature is 90-150°C.

[0015] More preferably, in step S1, the length of the nanocellulose is <2000 nm and the diameter is <100 nm. Even more preferably, the length of the nanocellulose is 500-1000 nm and the diameter is 20-50 nm.

[0016] More preferably, in step S2, the alkalization specifically involves immersing the nanocellulose in an alkaline solution for alkalization. More preferably, the alkaline solution is a 1-3 mol / L aqueous solution of sodium hydroxide.

[0017] More preferably, in step S2, the etherification specifically involves: reacting the alkalized nanocellulose with isopropanol to obtain nanocellulose ether.

[0018] More preferably, in step S3, the vegetable oil is selected from at least one of soybean oil, palm oil, and rapeseed oil.

[0019] More preferably, in step S3, the mass ratio of the vegetable oil to the nanocellulose ether is (0.1-1):1.

[0020] More preferably, in step S3, the reaction temperature is 80-100℃ and the reaction time is 4-8h.

[0021] Preferably, the length of the vegetable oil-modified cellulose ether is <2000 nm. More preferably, the length of the vegetable oil-modified cellulose ether is 500-1000 nm.

[0022] Preferably, the diameter of the vegetable oil-modified cellulose ether is <100 nm. More preferably, the diameter of the vegetable oil-modified cellulose ether is 20-50 nm.

[0023] Preferably, the degree of substitution of the vegetable oil-modified cellulose ether is 0.5-3.5.

[0024] Preferably, the bio-based emulsion is a bio-based acrylic emulsion.

[0025] More preferably, the bio-based emulsion is a bio-based acrylate emulsion formed by emulsification and polymerization of monomers such as bio-based alkyl acrylate and alkyl methacrylate, with a solid content of 40%-58%, a bio-based content of 20%-30%, a pH of 8-9, and a glass transition temperature of -25℃-0℃.

[0026] More preferably, the bio-based emulsion is selected from one of Badifu RS-769, RS-779, and RS-789.

[0027] Preferably, the filler is selected from one or more of heavy calcium carbonate, light calcium carbonate, talc, and kaolin.

[0028] More preferably, the calcium carbonate content of the superphosphate is ≥98%, the whiteness is 90%-95%, and the particle size is 600-1000 mesh.

[0029] Preferably, the additives include dispersants, defoamers, preservatives, thickeners, and pH adjusters.

[0030] More preferably, the dispersant is selected from sodium polycarboxylate and / or ammonium polycarboxylate. Even more preferably, the dispersant is selected from one or more of the following: SN-504, ADS2500, ADS1288, etc., from S.N.C., Dow Chemical.

[0031] More preferably, the defoamer is selected from one or more of polysiloxanes, polyether-modified dimethylsiloxanes, and polymer-composite mineral oils. Even more preferably, the defoamer is selected from one or more of Sanopco SN-154, BASF ST 2410AG, and NXZ, in combination.

[0032] More preferably, the preservative is selected from one or more of 5-chloro-2-methylisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and 1,2-benzisothiazolin-3-one. Even more preferably, the preservative is selected from one or more of TorActivicIDE LPC5, ActivicIDE CBM 2, and ActivicIDE BW20.

[0033] More preferably, the thickener is a water-based nonionic modified polyurethane thickener. Even more preferably, the thickener is selected from one or more of RM-8W, RM-5000, RM-2020, etc.

[0034] More preferably, the pH adjuster is selected from one or more of diethanolamine, butyldiethylenediamine, 2-amino-2-methyl-1-propanol, and 2-amino-2-ethyl-1,3-propanediol.

[0035] The second aspect of the present invention provides a method for preparing the bio-based coating described in the first aspect, comprising the following steps: mixing the raw materials to obtain the bio-based coating.

[0036] Preferably, the process includes the following steps: first, water, vegetable oil-modified nanocellulose, dispersant, some additives, filler, and pigment are added sequentially to a dispersion tank and dispersed at a speed of 800-1200 rpm. The speed is then adjusted to medium speed. Next, bio-based emulsion and the remaining additives are added sequentially and dispersed at a speed of 500-800 rpm to prepare a bio-based coating.

[0037] The third aspect of the present invention provides the application of the bio-based coatings described in the first aspect in construction.

[0038] Preferably, the bio-based coating is used in interior wall coatings.

[0039] The beneficial effects of this invention are:

[0040] This invention provides a highly environmentally friendly, washable, and stain-resistant bio-based coating. All raw materials used are zero-VOC, water-based, environmentally friendly materials. The emulsion utilizes a novel bio-based emulsion, employing long-chain bio-based alkyl acrylates containing unsaturated olefins, prepared through bio-fermentation, chemical degradation, or conversion, to replace petroleum-derived emulsion monomers. This polymerization broadens the glass transition temperature, lowers the film-forming temperature, and results in a more compact, encapsulating long-chain molecular structure. This allows for excellent film-forming properties and low-temperature stability even without the use of film-forming aids and antifreeze / thaw agents. The cellulose ether uses a nano-cellulose modified with plant oils through enzymatic decomposition. Compared to traditional cellulose ethers, this offers advantages such as environmentally friendly, low-energy production and renewable raw materials. Its slender structure and the presence of both hydrophilic and oleophilic ends further enhance the coating's washability and stain resistance. Compared to existing coatings, this bio-based coating offers advantages such as green, environmentally friendly, energy-saving, and carbon-reducing raw materials, along with strong washability and stain resistance, making it suitable for interior wall coatings. Detailed Implementation

[0041] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.

[0042] Example 1

[0043] This embodiment provides a bio-based coating with the following raw material information: dispersant is Sanopco SN-5040; defoamer-1 is Sanopco SN-154; defoamer-2 is BASF ST 2410AG; heavy calcium carbonate (calcium carbonate) is CC700; titanium dioxide is CNNC Titanium Dioxide R216; pH adjuster is Eastman VANTEX-T; bio-based emulsion is BADF RS-769; preservative is TorActivicIDE LPC5; thickener is RM-8W; the specific preparation steps are as follows:

[0044] 1. Preparation of vegetable oil-modified cellulose ethers

[0045] S1. Nano-sizing: Poplar pulp and cellulase were stirred at 300 rpm at 50°C for 4 hours. The cellulase was a composite enzyme consisting of 1,4-β-D-endoglucanase and 1,4-β-D-exoglucanase mixed in a mass ratio of 1:1. The amount of the composite enzyme and poplar pulp was 220 U / g (based on enzyme activity). After the reaction, the reaction product was inactivated at a temperature above 90°C and then ground in a colloid disc grinder to prepare nanocellulose slurry. The diameter of the nanocellulose in the slurry was 10-20 nm and the length was 100-500 nm.

[0046] S2, Etherification: Nanocellulose is added to an aqueous solution of sodium hydroxide with a concentration of about 2 mol / L (the mass ratio of cellulose slurry to sodium hydroxide solution is 5:1), stirred at medium speed of 800 rpm for 45 s, and then isopropanol with a mass of 3 times that of cellulose slurry is added. The mixture is stirred at high speed of 1500 rpm for 120 min to carry out the etherification reaction to obtain nanohydroxyethyl cellulose ether.

[0047] S3. Bridging modification: The etherified nano-hydroxyethyl cellulose ether was mixed with isopropanol at a mass ratio of 1:2. The mixture was stirred at 75°C and 1800 rpm for 150 min. Then, soybean oil (0.3 times the mass of cellulose ether) and bromododecane (0.2 times the mass of cellulose ether) were added. The mixture was heated to 90°C and reacted for 6 h. After centrifugation, washing with water and drying, the modified cellulose ether was obtained.

[0048] 2. Preparation of bio-based coatings

[0049] The formulation of Example 1 is shown in Table 1 (all figures are parts by weight). Water, vegetable oil-modified cellulose ether, dispersant, defoamer-1, heavy calcium carbonate, titanium dioxide and multifunctional additives were added to the dispersion tank in sequence. After dispersing at high speed of 800-1200 rpm for 10 min, the speed was adjusted to medium speed of 500-800 rpm. The remaining materials, such as bio-based emulsion, defoamer-2, preservative and thickener, were added in sequence and stirred for 5 min to prepare a bio-based coating.

[0050] Example 2-3

[0051] The formulations of Examples 2-3 are shown in Table 1 (all figures are parts by weight). The preparation methods of the bio-based coatings in Examples 2-3 are the same as those in Example 1.

[0052] Comparative Examples 1-3

[0053] The formulations of Comparative Examples 1-3 are shown in Table 1 (all figures are parts by weight). The raw material information is as follows: the cellulose ether is Ashland 250HBR, the acrylic emulsion is Budd-F RS-5939, the film-forming aid is COASOL from Chemoxy in the UK, and the antifreeze is propylene glycol.

[0054] The preparation method of the coating of Comparative Example 1 is as follows: water, cellulose ether, dispersant, defoamer-1, heavy calcium carbonate, titanium dioxide and multifunctional additives are added to the dispersion tank in sequence, dispersed at high speed of 800-1200 rpm for 10 min, and then the speed is adjusted to medium speed of 500-800 rpm. Bio-based emulsion, defoamer-2, preservative and thickener are added in sequence and stirred for 5 min to prepare bio-based coating.

[0055] The preparation method of the coatings in Comparative Examples 2-3 is as follows: water, cellulose ether, dispersant, defoamer-1, heavy calcium carbonate, titanium dioxide and multifunctional additives are added to a dispersion tank in sequence. After dispersion at high speed of 800-1200 rpm for 10 min, the speed is adjusted to medium speed of 500-800 rpm. Bio-based emulsion, defoamer-2, preservative, film-forming aid, antifreeze and thickener are added in sequence and stirred for 5 min to prepare bio-based coatings.

[0056] Table 1

[0057]

[0058]

[0059] Experimental Test

[0060] To evaluate the technical indicators of the above embodiments and comparative examples, tests were conducted according to the requirements for superior-grade topcoats in GB / T 9756-2018 Synthetic Resin Emulsion Interior Wall Coatings. The stain resistance performance was tested according to the stain resistance performance test method for interior wall coatings in GB / T 9780-2013 Architectural Coatings Coatings Coatings. The judgment criteria were based on the standard of GB / T 34676-2017 Interior Wall Coatings for Children's Room Decoration, as shown in Table 2.

[0061] Table 2

[0062] Test Project Test methods Evaluation criteria State within the container GB / T 9756-2018 There are no lumps, and the mixture becomes homogeneous after stirring. Constructability GB / T 9756-2018 Two coats of paint applied without obstruction Drying time (surface dry) / h GB / T 9756-2018 ≤2 Low temperature stability (3 cycles) GB / T 9756-2018 Undeteriorated Low temperature film formation GB / T 9756-2018 No abnormalities in film formation at 5℃ Coating appearance GB / T 9756-2018 normal Contrast ratio GB / T 9756-2018 ≥0.95 Alkali resistance GB / T 9756-2018 No abnormalities in 96 hours Washability / cycle GB / T 9756-2018 6000 times Overall stain resistance GB / T 9780-2013 ≥45

[0063] After evaluating Examples 1-3 and Comparative Examples 1-3 according to the above evaluation method, the results are shown in Table 3:

[0064] Table 3

[0065]

[0066] As shown in Table 3, the comparison between Example 2 and Example 1, Comparative Example 1 and Example 2, and Comparative Example 3 and Comparative Example 2 demonstrates that the nano-cellulose ether prepared by bio-enzymatic decomposition and vegetable oil modification of this invention has a slender structure and a structure with both hydrophilic and oleophilic ends compared to ordinary cellulose ethers. This can improve the washability and overall stain resistance of bio-based coatings, and can be further improved with increasing usage.

[0067] The comparison of the results of Example 3 with Example 2 and Comparative Example 2 with Example 2 demonstrates that the long carbon chain molecular structure of this bio-based emulsion can improve the washability and overall stain resistance of bio-based coatings. Furthermore, increasing the amount of bio-based emulsion used can further enhance these properties. Comparing the formulations of Comparative Example 2 and Example 2, this bio-based emulsion of the present invention can achieve the same low-temperature stability and low-temperature film-forming performance without adding VOCs-containing raw materials such as film-forming aids and antifreeze agents. This also gives the bio-based coating of the present invention zero VOCs and high environmental friendliness.

[0068] The present invention provides an environmentally friendly, scrub-resistant, and stain-resistant bio-based coating and its preparation method. The prepared bio-based coating meets and exceeds the requirements of the superior grade of topcoat in GB / T 9756-2018 Synthetic Resin Emulsion Interior Wall Coatings.

[0069] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A bio-based coating, characterized in that, The raw materials include the following parts by weight: 0.2-1 parts of vegetable oil modified cellulose ether, 20-40 parts of filler, 5-15 parts of pigment, 0.5-2.5 parts of additives, 20-40 parts of bio-based emulsion, and 20-40 parts of water; The vegetable oil-modified cellulose ether is prepared by a method comprising the following steps: S1. Biomass raw materials are mixed with cellulase and reacted. The reaction product is then inactivated and ground to obtain nanocellulose. S2. The nanocellulose is alkalized and etherified to obtain nanocellulose ether; S3. The nanocellulose ether is reacted with vegetable oil and bromoalkane to obtain vegetable oil modified cellulose ether.

2. The bio-based coating according to claim 1, characterized in that, The raw materials and process conditions in step S1 are selected from one or more of the following: A) The biomass raw material is selected from wood pulp or bamboo pulp; B) The cellulase is selected from one or more of 1,4-β-D-endoglucanase, 1,4-β-D-exoglucanase, and β-glucosidase; C) The ratio of the cellulase activity to the mass of the biomass feedstock is (100-500) U:1g; D) The reaction temperature is 40-60℃; the reaction time is 3-5 h; E) The inactivation temperature is 90-150℃.

3. The bio-based coating according to claim 1, characterized in that, In step S2, the alkalization specifically involves alkalizing the nanocellulose by immersing it in an alkaline solution. And / or, the etherification specifically involves: reacting alkalized nanocellulose with isopropanol to obtain nanocellulose ether.

4. The bio-based coating according to claim 1, characterized in that, The raw material and process conditions in step S3 are selected from one or more of the following: F) The vegetable oil mentioned is selected from at least one of soybean oil, palm oil, and rapeseed oil; G) The mass ratio of the vegetable oil to the nanocellulose ether is (0.1-1):1; The reaction temperature of H) is 80-100℃; the reaction time is 4-8 h.

5. The bio-based coating according to claim 1, characterized in that, The length of the vegetable oil-modified cellulose ether is <2000 nm; And / or, the diameter of the vegetable oil-modified cellulose ether is <100 nm; And / or, the degree of substitution of the vegetable oil-modified cellulose ether is 0.5-3.

5.

6. The bio-based coating according to claim 1, characterized in that, The bio-based emulsion is a bio-based acrylic emulsion.

7. The bio-based coating according to claim 1, characterized in that, The filler is selected from one or more of heavy calcium carbonate, light calcium carbonate, talc, and kaolin. And / or, the additives include dispersants, defoamers, preservatives, thickeners, and pH adjusters.

8. A method for preparing the bio-based coating according to any one of claims 1-7, characterized in that, The process includes the following steps: mixing the raw materials to obtain the bio-based coating.

9. The application of the bio-based coating according to any one of claims 1-7 in construction.

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