Rose essential oil water-based bi-component electrostatic spraying solid color finish paint and preparation method thereof

Abstract

The invention discloses rose essential oil water-based bi-component electrostatic spraying solid-color finish paint and a preparation method thereof. The rose essential oil water-based bi-component electrostatic spraying solid-color finish paint comprises a component A and a component B, the component A is prepared from the following components in parts by weight: 30 to 40 parts of waterborne hydroxyl polyurethane emulsion; 15 to 25 parts by weight of deionized water; 15-20 parts by weight of an inorganic pigment; 1-2 parts by weight of a dispersant; 0.5-1 part by weight of a leveling agent; 0.5-1 part by weight of a preservative; 0.5-1 part by weight of rose essential oil; the component B is prepared from 10 to 15 parts by weight of polyisocyanate; and 2-10 parts by weight of propylene glycol methyl ether acetate. According to the invention, the inner layer is a polymer (PEG or PLGA), and has good slow release property and volatile protection effect; the middle layer is an intelligent response layer and can adjust the release rate of the essential oil according to external stimulation; the outer layer is an inorganic protective layer such as silicon dioxide, so that the mechanical strength and stability of the microcapsule are improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a rose essential oil water-based two-component electrostatic spraying solid color topcoat and a preparation method thereof. Background Art

[0002] With the development of coating technology, water-based coatings, as an environmentally friendly material, have gradually attracted widespread attention and application due to their advantages such as low VOC (volatile organic compound) emissions, non-toxicity, and easy operation. As an important branch, water-based two-component coating systems are usually composed of resins, curing agents, pigments, additives, etc. Rose essential oil is often added to certain coatings due to its unique aroma and excellent biological activity to improve the functionality and added value of the coating. In addition to giving the coating aromatic functions, rose essential oil also has antioxidant and antibacterial properties, making it suitable for the development of high-end coatings.

[0003] However, solid color topcoats affect the release rate and aroma intensity of essential oils due to the presence of pigments. It is necessary to find a topcoat formula that can ensure the long-lasting release of essential oils. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies in the prior art, the present invention provides a rose essential oil water-based two-component electrostatic spray solid color topcoat and a preparation method thereof, which solves the problems raised in the above background technology.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A rose essential oil water-based two-component electrostatic spray solid color topcoat, the rose essential oil water-based two-component electrostatic spray solid color topcoat comprising component A and component B;

[0009] Component A:

[0010] Aqueous hydroxy polyurethane emulsion: 40-50 parts by weight;

[0011] Pigment: 10-15 parts by weight;

[0012] Kaolin: 5-10 parts by weight;

[0013] Dispersant: 0.5-1 parts by weight;

[0014] Defoaming agent: 0.5-0.8 parts by weight;

[0015] Wetting agent: 0.1-0.3 parts by weight;

[0016] Essential oil sustained-release agent: 1-2 parts by weight;

[0017] Microcapsule stabilizer: 0.5-1 parts by weight;

[0018] Microencapsulated rose essential oil: 3-5 parts by weight;

[0019] Deionized water: 20-25 parts by weight;

[0020] Component B:

[0021] Isocyanate curing agent: 20-40 parts by weight;

[0022] Film-forming aid: 3-5 parts by weight;

[0023] Deionized water 50-60 parts by weight.

[0024] The microencapsulated rose essential oil is composed of the following substances:

[0025] Core material: Rose essential oil

[0026] Inner wall material: polyethylene glycol PEG;

[0027] Middle wall material: chitosan, wherein the chitosan is cross-linked with glutaraldehyde;

[0028] Outer wall material: Silica nanoparticles

[0029] The surface is modified with polyethylene glycol to increase the hydrophilicity of the microcapsules.

[0030] The essential oil sustained-release agent is a mixture of mesoporous silicon dioxide and poly N-isopropylacrylamide.

[0031] The capsule stabilizer is a PEO-PPO-PEO triblock copolymer.

[0032] The hydroxyl content in the aqueous hydroxyl polyurethane emulsion is 1.5% to 6.5%.

[0033] The solid content of the aqueous hydroxyl polyurethane emulsion is 30-40wt%, and the viscosity at 25 degrees Celsius is 1000-10000mPa·s;

[0034] The isocyanate curing comprises:

[0035] HDI trimer 10-20 parts by weight

[0036] Isophorone diisocyanate 5-10 parts by weight

[0037] 5-10 parts by weight of dicyclohexylmethane diisocyanate.

[0038] A method for preparing a rose essential oil water-based two-component electrostatic spray solid color topcoat, wherein the rose essential oil water-based two-component electrostatic spray solid color topcoat comprises an A component and a B component;

[0039] Component A:

[0040] Aqueous hydroxy polyurethane emulsion: 40-50 parts by weight;

[0041] Pigment: 10-15 parts by weight;

[0042] Kaolin: 5-10 parts by weight;

[0043] Dispersant: 0.5-1 parts by weight;

[0044] Defoaming agent: 0.5-0.8 parts by weight;

[0045] Wetting agent: 0.1-0.3 parts by weight;

[0046] Essential oil sustained-release agent: 1-2 parts by weight;

[0047] Microcapsule stabilizer: 0.5-1 parts by weight;

[0048] Microencapsulated rose essential oil: 3-5 parts by weight;

[0049] Deionized water: 20-25 parts by weight;

[0050] Component B:

[0051] Isocyanate curing agent: 20-40 parts by weight;

[0052] Film-forming aid: 3-5 parts by weight;

[0053] Deionized water 50-60 parts by weight;

[0054] Mix components A and B evenly and package them separately to obtain rose essential oil water-based two-component electrostatic spray solid color topcoat

[0055] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0056] The present invention uses the high specific surface area of ​​nanoporous materials to adsorb and temporarily lock a portion of essential oils, and PNIPAM undergoes phase change at room temperature or high temperature. Micro-mesoporous silica or ordered mesoporous carbon particles are compounded with PNIPAM polymer materials, uniformly dispersed in the coating system, and used together with microcapsules. It ensures that under different temperature conditions, the sustained-release agent can effectively regulate the release of essential oils and prolong the duration of the aroma.

[0057] The PEO-PPO-PEO triblock copolymer of the present invention is a water-soluble surfactant block copolymer, and the amphiphilic structure of the block copolymer (PEO is a hydrophilic segment and PPO is a hydrophobic segment) can self-assemble between the microcapsule and the coating matrix, reduce the interfacial tension, and enhance the stability of the microcapsule in the water-based coating. Through synergistic action, a protective layer is formed on the surface of the microcapsule, effectively inhibiting the aggregation of the microcapsule in the coating, and improving its dispersion stability through charge repulsion or steric hindrance effect.

[0058] The inner layer of the present invention is a polymer (PEG or PLGA), which has good sustained release and volatility protection; the middle layer is an intelligent response layer, which can adjust the release rate of essential oils according to external stimuli (such as pH, temperature changes); the outer layer is an inorganic protective layer such as silicon dioxide, which increases the mechanical strength and stability of the microcapsule. Chitosan, as an intermediate layer material, can swell or disintegrate when the pH value changes, prompting the inner core to release essential oils. At the same time, temperature changes or friction can destroy the outer silicon dioxide film and promote further release. All materials of the present invention are environmentally friendly and suitable for use in water-based coating systems. DETAILED DESCRIPTION

[0059] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] In the following examples and comparative examples:

[0061] Hydroxyl-containing waterborne polyurethane dispersion:

[0062] Covestro's Bayhydrol UH 2592 has a hydroxyl content of 2.1%, a solid content of 45%, and a viscosity of 500 mPa·s.

[0063] HDI trimer VPLS2151 (Covestro)

[0064] IPDI (isophorone diisocyanate) T 1890 (Evonik)

[0065] Dicyclohexylmethane diisocyanate: Desmodur W H12MDI

[0066] Poly(lactic-co-glycolic acid) (PLGA) Resomer RG 503H (50:50 lactic acid:glycolic acid ratio);

[0067] Polyethylene glycol (PEG400)

[0068] Emulsifier Triton TM X-100

[0069] Chitosan solution

[0070] Glutaraldehyde solution 25%

[0071] Tetraethoxysilane 40

[0072] Polyethylene glycol modification agent mPEG-Silane

[0073] Mesoporous silica Mesoporous Silica Nanoparticles (MSNs);

[0074] Preparation method of rose essential oil microcapsules:

[0075] Step 1: Preparation of core microcapsules (emulsion polymerization method)

[0076] Preparation of organic phase of rose essential oil:

[0077] Weigh the required amount of rose essential oil (5 g), dissolve it in an appropriate amount of dichloromethane (10-20 ml), and add polylactic acid-co-glycolic acid (PLGA, 3 g) or polyethylene glycol (PEG, 3 g).

[0078] Ultrasonic treatment was used to ensure that the essential oil and polymer were evenly dispersed in the organic phase.

[0079] Preparation of aqueous emulsified system:

[0080] Mix deionized water (50 ml) and an emulsifier (such as polyethylene glycol octylphenyl ether, 1% to 2%) in a stirrer. Start the stirrer and set the stirring speed to medium (400-500 rpm).

[0081] Emulsion Formation:

[0082] The organic phase is added dropwise to the stirred aqueous phase to form an oil-in-water (O / W) emulsion. The stirring time is controlled between 30 minutes and 1 hour to ensure the stability of the emulsion.

[0083] Organic solvent evaporation:

[0084] After the emulsion is formed, the emulsion is transferred to a rotary evaporator, and dichloromethane is gradually evaporated at 40° C., so that the polymer is solidified in the water phase and the rose essential oil is encapsulated to form inner core microcapsules.

[0085] Microcapsule drying:

[0086] The prepared core microcapsules are dried using a spray dryer or a freeze dryer to obtain dried rose essential oil microcapsules. The particle size is controlled between 10 and 20 microns.

[0087] Step 2: Middle wall material coating (chitosan)

[0088] Chitosan solution preparation:

[0089] Prepare a 1% chitosan solution and adjust the pH to 4-5 with acetic acid to ensure that the chitosan is completely dissolved.

[0090] Middle layer covering:

[0091] The dried core microcapsules were added into the chitosan solution and stirred evenly (300 rpm), and the pH was maintained between 4 and 5 to ensure that the chitosan was evenly coated on the surface of the microcapsules.

[0092] Glutaraldehyde is selected for cross-linking, 0.5% glutaraldehyde solution is added, and stirred for 30 minutes to cross-link the chitosan to form a dense middle wall material.

[0093] Step 3: Outer wall material coating (silicon dioxide layer)

[0094] Preparation of silica outer layer by sol-gel method:

[0095] In an alkaline aqueous solution (pH 8-9), add microcapsules and slowly add tetraethoxysilane (TEOS, 1-2 ml). TEOS is hydrolyzed under alkaline conditions to gradually form a silicon dioxide layer that is deposited on the surface of the microcapsules.

[0096] The reaction lasts for 2-3 hours to ensure that the outer layer of silica is dense and stable.

[0097] Outer layer drying and purification:

[0098] After the silica deposition was completed, the excess reactants were removed by vacuum filtration and washed several times with deionized water before being spray dried.

[0099] Step 4: Surface modification (PEG modification)

[0100] PEGylation:

[0101] The dried microcapsules were redispersed in an ethanol-water mixed solution (50% ethanol), and polyethylene glycol was added to the solution. The mixture was stirred for 1 hour to allow PEG to be evenly modified on the surface of the silica layer, thereby increasing the hydrophilicity of the microcapsules.

[0102] Drying after PEG modification:

[0103] The modified microcapsules are treated by spray drying to obtain final rose essential oil multi-layer wall microcapsules.

[0104] Preparation process steps of essential oil sustained-release agent:

[0105] Preparation process steps of essential oil sustained-release agent:

[0106] 100 parts by weight of mesoporous silica are dispersed in 400 parts by weight of ethanol and subjected to ultrasonic treatment for 15 minutes; 20 parts by weight of polyethylene glycol modifier is added to impart hydrophilic or lipophilic groups to the surface of the particles, and the ethanol is removed by a rotary evaporator to obtain modified mesoporous silica particles;

[0107] 100 parts by weight of N-isopropylacrylamide monomer was weighed and dissolved in 400 parts by weight of deionized water, and stirred evenly. The pH of the solution was adjusted to 7 to ensure that the monomer was fully dissolved, thereby obtaining a NIPAM solution.

[0108] Add 10 parts by weight of cross-linking agent N,N'-methylenebisacrylamide to 100 parts by weight of NIPAM solution, stir to make it uniformly dispersed, add 0.5 parts by weight of initiator to the above system at room temperature; continue to add 5 parts by weight of modified mesoporous silica particles, use an ultrasonic processor to treat for -60 minutes to ensure that the particles are uniformly dispersed in the solution;

[0109] Under stirring conditions, the solution was heated to 35°C, the temperature was maintained, and stirring was continued to initiate a polymerization reaction, and the polymerization was carried out for 6 hours. During the polymerization, the gelation process was tested by sampling. When the reaction was completed, a small amount of ethanol was added to terminate the polymerization reaction, and the polymer was separated from the unreacted monomer by a vacuum filtration device; the product was washed alternately with a large amount of deionized water and ethanol for 5 times, and after each washing, it was separated by vacuum filtration or centrifugation to obtain a purified PNIPAM-mesoporous particle composite material;

[0110] The purified PNIPAM-mesoporous particle composite material was placed in a vacuum drying oven and dried at 50° C. to a constant weight to obtain a PNIPAM-mesoporous particle composite material.

[0111] The topcoat formula is as follows:

[0112] Component A:

[0113] Water-based hydroxy polyurethane emulsion: 40 parts by weight;

[0114] Pigment: 15 parts by weight;

[0115] Kaolin: 10 parts by weight;

[0116] Dispersant: 0.5 parts by weight;

[0117] Defoaming agent: 0.5 parts by weight;

[0118] Wetting agent: 0.1 parts by weight;

[0119] Essential oil sustained-release agent: 1-2 parts by weight;

[0120] Microcapsule stabilizer: 0.5-1 parts by weight;

[0121] Microencapsulated rose essential oil: 3-5 parts by weight;

[0122] Deionized water: 25 parts by weight;

[0123] Component B:

[0124] Isocyanate curing agent: 40 parts by weight;

[0125] Film-forming aid propylene glycol methyl ether: 5 parts by weight;

[0126] 50 parts by weight of deionized water.

[0127] Experimental process:

[0128] Stability analysis of rose essential oil

[0129] 5 g of microencapsulated rose essential oil was selected to prepare a microcapsule topcoat, which was applied to a substrate. After curing, the substrate was placed in a water bath container, and the temperature was set to increase by 2 degrees Celsius per hour from 30 degrees Celsius to 80 degrees, and then dropped back to 30 degrees Celsius.

[0130] The electron microscope was used to analyze the damage ratio of microcapsules in the microcapsule topcoat.

[0131] Rose essential oil release analysis

[0132] According to the above-mentioned embodiments and comparative examples, a microcapsule topcoat was prepared, and the microcapsule topcoat was coated on a substrate. After curing, the substrate was placed in a water bath container and maintained at 40 degrees Celsius.

[0133] After 24 hours, a certain volume of release medium was extracted using a sampler. The extracted release medium was placed in a clean 500 ml sample bottle and marked. The release medium in the sample bottle was analyzed using gas chromatography-mass spectrometry (GC-MS) to calculate the content of rose essential oil in the sample bottle.

[0134]

[0135]

[0136] In the comparative example, if the microcapsule stabilizer and the essential oil sustained-release agent are not added, the microcapsule damage reaches 15.4% in the experiment. It can be seen that the microcapsule stabilizer and the essential oil sustained-release agent of the present invention can greatly improve the stability of the microcapsule.

[0137] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A rose essential oil water-based two-component electrostatic spray solid color topcoat, characterized in that: The rose essential oil water-based two-component electrostatic spray solid color topcoat comprises component A and component B; Component A: Aqueous hydroxy polyurethane emulsion: 40-50 parts by weight; Pigment: 10-15 parts by weight; Kaolin: 5-10 parts by weight; Dispersant: 0.5-1 parts by weight; Defoaming agent: 0.5-0.8 parts by weight; Wetting agent: 0.1-0.3 parts by weight; Essential oil sustained-release agent: 1-2 parts by weight; Microencapsulated rose essential oil: 3-5 parts by weight; Deionized water: 20-25 parts by weight; Component B: Isocyanate curing agent: 20-40 parts by weight; Film-forming aid: 3-5 parts by weight; Deionized water 50-60 parts by weight.

2. A rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 1, characterized in that: The microencapsulated rose essential oil is composed of the following substances composition: Core material: Rose essential oil Inner wall material: polyethylene glycol PEG; Middle wall material: chitosan, wherein the chitosan is cross-linked with glutaraldehyde; Outer wall material: Silica nanoparticles The surface is modified with polyethylene glycol to increase the hydrophilicity of the microcapsules.

3. A rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 2, characterized in that: The preparation method of the microencapsulated rose essential oil is as follows: Step 1: Preparation of core microcapsules Weigh the required amount of rose essential oil 5g, dissolve it in an appropriate amount of dichloromethane 10-20ml, and add 3-4g of polyethylene glycol; use an ultrasonic processor to treat it to ensure that the essential oil and the polymer are evenly dispersed in the organic phase; Mix 50-60 ml of deionized water and 5-6 g of emulsifier polyethylene glycol octylphenyl ether in a stirrer, start the stirrer, and set the stirring speed to 400-500 rpm; Add the organic phase drop by drop into the stirred aqueous phase to form an oil-in-water emulsion. The stirring time is controlled between 30 minutes and 1 hour to ensure the stability of the emulsion. After the emulsion is formed, the emulsion is transferred to a rotary evaporator, and dichloromethane is gradually evaporated at 35-40° C., so that the polymer is solidified in the water phase and the rose essential oil is encapsulated to form core microcapsules; Using a spray dryer, the prepared core microcapsules are dried to obtain dry rose essential oil microcapsules, with the particle size controlled between 10 and 20 microns; Step 2: Middle wall material cladding Prepare a 1% chitosan solution and adjust the pH to 4-5 with acetic acid to ensure that the chitosan is completely dissolved; Add the dried core microcapsules into the chitosan solution, stir evenly at 100-300 rpm, maintain the pH between 4-5, and ensure that the chitosan is evenly coated on the surface of the microcapsules; Add 0.5% to 1% glutaraldehyde solution and stir for 30-60 minutes to cross-link the chitosan to form a dense middle wall material; The cross-linked microcapsules are vacuum filtered to remove excess cross-linking agent and unreacted chitosan, and then freeze-dried or spray-dried; Step 3: Outer wall covering Preparation of silica outer layer by sol-gel method: In an alkaline aqueous solution of pH 8-9, add microcapsules and slowly add 1-2 ml of tetraethoxysilane. Tetraethoxysilane is hydrolyzed under alkaline conditions to gradually form a silicon dioxide layer that is deposited on the surface of the microcapsules. The reaction lasts for 2-3 hours to ensure that the outer layer of silicon dioxide is dense and stable. After the silica deposition is completed, the excess reactants are removed by vacuum filtration and washed with deionized water several times before being spray dried; Step 4: Surface modification The dried microcapsules were redispersed in an ethanol-water mixed solution, and a polyethylene glycol modifier was added, and the reaction was stirred for 1 hour to uniformly modify the PEG on the surface of the silica layer and increase the hydrophilicity of the microcapsules; the modified microcapsules were treated by spray drying to obtain the final rose essential oil multi-layer wall microcapsules.

4. A rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 3, characterized in that: The essential oil sustained-release agent is a mixture of mesoporous silicon dioxide and poly N-isopropylacrylamide.

5. A rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 4, characterized in that: The capsule stabilizer is a PEO-PPO-PEO triblock copolymer.

6. The rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 1, characterized in that: The hydroxyl content in the aqueous hydroxyl polyurethane emulsion is 1.5% to 6.5%.

7. The rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 1, characterized in that: The solid content of the aqueous hydroxyl polyurethane emulsion is 30-40 wt %, and the viscosity at 25 degrees Celsius is 1000-10000 mPa·s.

8. The rose essential oil water-based two-component electrostatic spray solid color topcoat according to claim 1, characterized in that: The isocyanate curing comprises: HDI trimer 10-20 parts by weight Isophorone diisocyanate 5-10 parts by weight 5-10 parts by weight of dicyclohexylmethane diisocyanate.

9. A method for preparing a rose essential oil water-based two-component electrostatic spray solid color topcoat, characterized in that: The rose essential oil water-based two-component electrostatic spray solid color topcoat comprises component A and component B; Component A: Aqueous hydroxy polyurethane emulsion: 40-50 parts by weight; Pigment: 10-15 parts by weight; Kaolin: 5-10 parts by weight; Dispersant: 0.5-1 parts by weight; Defoaming agent: 0.5-0.8 parts by weight; Wetting agent: 0.1-0.3 parts by weight; Essential oil sustained-release agent: 1-2 parts by weight; Microcapsule stabilizer: 0.5-1 parts by weight; Microencapsulated rose essential oil: 3-5 parts by weight; Deionized water: 20-25 parts by weight; Component B: Isocyanate curing agent: 20-40 parts by weight; Film-forming aid: 3-5 parts by weight; Deionized water 50-60 parts by weight; The A and B components are mixed evenly and packaged separately to obtain a rose essential oil water-based two-component electrostatic spray solid color topcoat.

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