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

Abstract

The invention discloses a rose essential oil water-based bi-component electrostatic spraying solid color primer and a preparation method thereof. The rose essential oil water-based bi-component electrostatic spraying solid color primer 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 to 0.8 part by weight of a defoaming 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 3-5 parts by weight of a coalescing agent. Through non-covalent interaction such as electrostatic adsorption, hydrogen bonds and hydrophobic interaction, cationic and anionic polyelectrolyte or other functional materials are deposited on the surface of the substrate layer by layer, and a stable multi-layer structure can be formed on the surface of the pigment, so that direct contact between the pigment and active substances such as rose essential oil is effectively avoided, and adverse chemical reaction is prevented.

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 spray solid color primer 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, the water-based two-component coating system is 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. However, when rose essential oil is applied to two-component water-based electrostatic spray coatings, there will be problems with chemical interactions between the pigment and the essential oil, resulting in color changes in the coating, reduced stability, or failure of the essential oil. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] 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 primer and a preparation method thereof, which solves the problems raised in the above background technology.

[0005] (II) Technical solution

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A rose essential oil water-based two-component electrostatic spray solid color primer, characterized in that the rose essential oil water-based two-component electrostatic spray solid color primer comprises component A and component B;

[0008] The A group is composed of:

[0009] Water-based hydroxy polyurethane emulsion: 30-40 parts by weight

[0010] Deionized water: 15-25 parts by weight

[0011] Inorganic pigment: 15-20 parts by weight

[0012] Dispersant: 1-2 parts by weight

[0013] Leveling agent: 0.5-1 parts by weight

[0014] Defoaming agent 0.5-0.8 parts by weight

[0015] Preservatives: 0.5-1 parts by weight

[0016] Rose essential oil: 0.5-1 parts by weight

[0017] Group B is composed of:

[0018] 10-15 parts by weight of polyisocyanate;

[0019] 3-5 parts by weight of film-forming aid.

[0020] The inorganic pigment is prepared by the following process steps:

[0021] Pigment pretreatment: Disperse the pigment in a solution and charge its surface;

[0022] First layer cationic polyelectrolyte deposition: depositing the first layer in a cationic polyelectrolyte solution;

[0023] Washing the pigment: Wash the pigment with deionized water to remove the unadsorbed polyelectrolyte;

[0024] Second layer anionic polyelectrolyte deposition: Deposit the second layer in anionic polyelectrolyte solution;

[0025] Repeated deposition of multiple layers: alternating deposition of cationic and anionic layers to form a multilayer structure;

[0026] Final encapsulation layer: Deposit the final encapsulation layer using a hydrophobic material;

[0027] Drying and curing: Dry at appropriate temperature to ensure pigment stability.

[0028] The cationic polyelectrolyte is selected from one or more of polydiallyldimethylammonium chloride, polyethyleneimine, chitosan and polyurethane.

[0029] The anionic polyelectrolyte is selected from one or more of sodium polystyrene sulfonate, sodium polyacrylate, sodium carboxymethyl cellulose and sodium alginate.

[0030] The hydrophobic material is selected from one or more of polytetrafluoroethylene, perfluoroalkyl phosphate, paraffin fluoride and polyvinyl fluoride.

[0031] The hydroxyl content in the aqueous hydroxyl polyurethane emulsion is 1.5%-6.5%.

[0032] The solid content of the aqueous hydroxyl polyurethane emulsion is 30-40wt%, and the viscosity at 25 degrees Celsius is 1000-10000mPa·s;

[0033] The polyisocyanate comprises:

[0034] HDI trimer 10-30 parts by weight

[0035] Isophorone diisocyanate 5-10 parts by weight

[0036] 5-10 parts by weight of dicyclohexylmethane diisocyanate.

[0037] A method for preparing a rose essential oil water-based two-component electrostatic spray solid color primer, wherein the rose essential oil water-based two-component electrostatic spray solid color primer comprises a component A and a component B;

[0038] The A group is composed of:

[0039] Water-based hydroxy polyurethane emulsion: 30-40 parts by weight

[0040] Deionized water: 15-25 parts by weight

[0041] Inorganic pigment: 15-20 parts by weight

[0042] Dispersant: 1-2 parts by weight

[0043] Leveling agent: 0.5-1 parts by weight

[0044] Defoaming agent 0.5-0.8 parts by weight

[0045] Preservatives: 0.5-1 parts by weight

[0046] Rose essential oil: 0.5-1 parts by weight

[0047] Group B is composed of:

[0048] 10-15 parts by weight of polyisocyanate;

[0049] 3-5 parts by weight of film-forming aid.

[0050] 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 primer.

[0051] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0052] In order to effectively avoid the problem of chemical reaction between pigment and essential oil, the present invention proposes a pigment surface modification technology. By coating the pigment particles, a thin film of inert or functional material can be formed on the surface to isolate the pigment from the external environment, thereby improving the chemical stability of the pigment.

[0053] The present invention is a technology for forming a multilayer nanofilm by depositing cationic and anionic polyelectrolytes or other functional materials layer by layer on the surface of a substrate through non-covalent interactions such as electrostatic adsorption, hydrogen bonding, and hydrophobic interaction. The method can form a stable multilayer structure on the surface of the pigment, thereby effectively avoiding direct contact between the pigment and active substances such as rose essential oil, thereby preventing adverse chemical reactions. DETAILED DESCRIPTION

[0054] 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.

[0055] Pigments are important ingredients in paint formulations, giving paints color and hiding power. Pigments are generally divided into organic pigments and inorganic pigments. Inorganic pigments (such as iron oxide, titanium dioxide, etc.) are widely used in paints with high requirements for weather resistance and chemical resistance due to their high chemical stability. However, in certain paint systems, especially those containing essential oils, the pigment surface may chemically react with the active ingredients in the essential oils, resulting in color distortion of the pigment or decreased functionality of the essential oils. This phenomenon is particularly prominent in organic pigments, which are prone to chemical reactions with organic solvents or components in essential oils due to the complexity of their molecular structure, thus affecting the performance of the paint.

[0056] In the following examples and comparative examples:

[0057] Hydroxyl-containing waterborne polyurethane dispersion:

[0058] Covestro's Bayhydrol UH 2592 has a hydroxyl content of 2.1%, a solid content of 45%, and a viscosity of 500 mPa·s.

[0059] HDI trimer VPLS2151 (Covestro)

[0060] IPDI (isophorone diisocyanate) T 1890 (Evonik)

[0061] Dicyclohexylmethane diisocyanate: Desmodur W H12MDI

[0062] Polytetrafluoroethylene, 60

[0063] Polysiloxane Dow 732

[0064] The recipe is as follows:

[0065] Group A is composed of:

[0066] Water-based hydroxy polyurethane emulsion: 40 parts by weight

[0067] Deionized water: 25 parts by weight

[0068] Inorganic pigment: 20 parts by weight

[0069] Dispersant: 2 parts by weight

[0070] Leveling agent: 1 part by weight

[0071] Defoamer 0.8 parts by weight

[0072] Preservative: 1 part by weight

[0073] Rose essential oil: 1 part by weight

[0074] Group B is composed of:

[0075] 10 parts by weight of polyisocyanate;

[0076] 5 parts by weight of film-forming aid propylene glycol butyl ether.

[0077] The composition and proportion of polyisocyanates include:

[0078] 20 parts by weight of HDI trimer, 10 parts by weight of isophorone diisocyanate, and 10 parts by weight of dicyclohexylmethane diisocyanate.

[0079] The pigment processing process is as follows:

[0080] 1. Pigment pretreatment

[0081] Add 10g of pigment (such as red iron oxide or titanium dioxide) to deionized water and add an appropriate amount of dispersant (TritonX-100). Use an ultrasonic disperser for 10-20 minutes to ensure that the pigment is evenly dispersed. Adjust the pigment surface to be positively charged by adding 0.1M NaOH solution, or directly use a cationic polyelectrolyte (PDDA) to charge the pigment.

[0082] 2. First layer of cationic polyelectrolyte deposition

[0083] Add the dispersed pigment to a cationic polyelectrolyte solution (1 mg / mL PDDA solution) and stir on a magnetic stirrer for 30 minutes to 1 hour to allow the cationic layer to evenly deposit on the pigment surface.

[0084] 3. Wash the paint

[0085] Separate the particles from the solution by centrifugation or filtration. Rinse 2-3 times with deionized water to ensure that excess polyelectrolyte is completely removed.

[0086] 4. Second layer of anionic polyelectrolyte deposition

[0087] The washed pigment was added to an anionic polyelectrolyte solution (1 mg / mL PSS solution) and stirred on a magnetic stirrer for 30 minutes to 1 hour to allow the anionic layer to be electrostatically adsorbed on the cationic layer.

[0088] 5. Repeated deposition of multiple layers

[0089] Repeat steps 2-4 to alternately deposit cationic (PDDA) and anionic (PSS) layers. Depending on the requirements, 10-50 layers can be deposited, and the thickness of each layer is between 5-20 nanometers.

[0090] 6. Final encapsulation layer

[0091] The last layer is deposited with a hydrophobic polyelectrolyte (such as polytetrafluoroethylene, PTFE) or other weather-resistant materials to further enhance the pigment's oil resistance and protective effect. Stir the deposition for 1 hour to ensure uniform coverage of the encapsulation layer.

[0092] 7. Drying and curing

[0093] The treated pigment particles are dried at 60-80°C to evaporate the water, and then baked at 120-150°C for 1-2 hours to cure.

[0094] Cationic polyelectrolytes are positively charged and can be electrostatically adsorbed on the pigment surface. The following are some of the cationic polyelectrolytes available:

[0095] Polydiallyldimethylammonium chloride (PDDA), a water-soluble, strong cationic polyelectrolyte.

[0096] Polyethyleneimine (PEI), a cationic polyelectrolyte with a highly branched structure, has a strong cation adsorption capacity.

[0097] Chitosan, chitosan is a natural polysaccharide with biocompatibility and good cationic charge. It is an environmentally friendly polyelectrolyte and is often used in the fields of biology and environmental protection.

[0098] Polyurethane (PU) is suitable for special scenarios, especially those requiring flexibility or mechanical properties.

[0099] 2. Anionic polyelectrolytes

[0100] It is negatively charged and can form charge pairs with cationic polyelectrolytes to form multilayer structures. The following anionic polyelectrolytes are available:

[0101] Sodium polystyrene sulfonate (PSS), a commonly used anionic polyelectrolyte, is soluble in water and has good chemical stability.

[0102] Sodium polyacrylate (PAA), another anionic polyelectrolyte, has a good charge density.

[0103] Sodium carboxymethyl cellulose (CMC), an anionic polyelectrolyte, has good biodegradability and charge characteristics.

[0104] Sodium alginate (Alginate), a natural anionic polyelectrolyte, has good biocompatibility and low toxicity.

[0105] 3. Hydrophobic materials

[0106] Hydrophobic materials are used to form an isolation layer to prevent pigments from direct contact with organic substances such as essential oils, while improving the weather resistance and corrosion resistance of pigments. The following are commonly used hydrophobic materials:

[0107] Polytetrafluoroethylene (PTFE)

[0108] It has excellent chemical resistance and hydrophobicity.

[0109] Perfluoroalkyl phosphates (PFOS) or perfluorooctanoic acid (PFOA)

[0110] It has extremely strong hydrophobic and oleophobic properties, forming a super hydrophobic surface.

[0111] Silicone

[0112] Polydimethylsiloxane (PDMS) has good hydrophobicity and chemical stability.

[0113] Fluorinated Wax

[0114] For hydrophobic and antifouling applications with excellent weather resistance and low surface energy.

[0115] Polyvinyl fluoride (PVDF)

[0116] High chemical stability, good UV and weather resistance.

[0117] Example 1 Modification of Iron Oxide Red Pigment

[0118] Pigment: Red iron oxide

[0119] Cationic polyelectrolyte: polydiallyldimethylammonium chloride (PDDA, 1 mg / mL)

[0120] Anionic polyelectrolyte: sodium polystyrene sulfonate (PSS, 1 mg / mL)

[0121] Hydrophobic material: polytetrafluoroethylene (PTFE, 0.5 mg / mL)

[0122] Dispersant: Triton X-100

[0123] Solvent: Deionized water

[0124] Essential oil: Rose essential oil

[0125] Pigment pretreatment:

[0126] 10g of red iron oxide was added to deionized water, and 0.1g of dispersant Triton X-100 was added, and ultrasonic treatment was performed for 10 minutes to ensure that the pigment particles were evenly dispersed. The pigment surface was positively charged by adding an appropriate amount of 0.1M NaOH solution.

[0127] First layer of cationic polyelectrolyte deposition:

[0128] The dispersed pigment was added into 1 mg / mL PDDA solution and stirred for 30 min to allow PDDA to adsorb on the pigment surface to form the first layer.

[0129] Cleaning:

[0130] The particles were separated from the solution by centrifugation (3000 rpm, 10 minutes) and washed three times with deionized water to remove unadsorbed PDDA.

[0131] Second layer of anionic polyelectrolyte deposition:

[0132] The washed pigment was added to a 1 mg / mL PSS solution and stirred for 30 min to allow the PSS to be deposited on the cationic polyelectrolyte layer.

[0133] Repeated deposition:

[0134] Ten layers were deposited alternately in the order of cation (PDDA)-anion (PSS), and the cleaning step was repeated between each layer to ensure uniform deposition of each layer.

[0135] Hydrophobic layer deposition:

[0136] The last layer was coated with a 0.5 mg / mL PTFE solution and stirred for 1 hour to form a hydrophobic isolation layer.

[0137] dry:

[0138] The modified pigment was dried at 80°C for 2 hours to form stable modified pigment particles.

[0139] Coating preparation:

[0140] The modified iron oxide red pigment is used, and according to the above-mentioned formula of water-based two-component coating, resin, curing agent, auxiliary agent and rose essential oil are added to prepare water-based solid color primer.

[0141] Performance test results:

[0142] Color stability:

[0143] After the paint was mixed with rose essential oil and stored for one month, it retained its original color without obvious fading or color change. The color difference ΔE value tested by the spectrometer was 0.5 (ΔE<1 means the color difference is invisible to the naked eye), indicating good color retention.

[0144] Abrasion resistance:

[0145] Wear resistance testing of the coating showed that after 500 frictions, the coating thickness was reduced by only 5.2 microns, demonstrating excellent mechanical properties.

[0146] Comparative Example 1:

[0147] Pigment: Red iron oxide

[0148] Essential oil: Rose essential oil

[0149] Pigment pretreatment:

[0150] 10 g of red iron oxide was directly added to deionized water, and 0.1 g of dispersant Triton X-100 was added, and ultrasonic treatment was performed for 10 minutes to ensure that the pigment particles were evenly dispersed.

[0151] Coating preparation:

[0152] Unmodified red iron oxide pigment was used, and resin, curing agent, additive and rose essential oil were added according to the same water-based two-component coating formula to prepare a water-based solid color primer.

[0153] result:

[0154] Color stability:

[0155] After one month of storage, the color of the paint faded significantly, with a ΔE value of 5.6, and significant color difference was visible to the naked eye.

[0156] Abrasion resistance:

[0157] After 500 rubbing cycles, the coating thickness decreased by 15.6 μm, indicating that the mechanical properties of the coating film were poor.

[0158] Comparative Example 2: Physical coating method to modify pigments

[0159] Experimental materials and steps:

[0160] The iron oxide red pigment was subjected to a traditional physical coating process, using silica sol to coat the pigment particles. After coating, it was dried and the coating was prepared using the same water-based two-component formulation.

[0161] Color stability:

[0162] The coating color was well maintained with a ΔE value of 2.6, but some color change was still observed, indicating that physical coating provided limited protection to the pigment.

[0163] Abrasion resistance:

[0164] After 500 frictions, the coating thickness was reduced by 14.8 microns, and the wear resistance was slightly improved, but still not as good as the embodiment.

[0165] Specific comparison:

[0166]

[0167] It can be seen from the experiment that PDDA has a higher cation density and can be more evenly adsorbed on the surface of the pigment to form a dense cation layer, showing better color stability and wear resistance. However, due to the loose chain structure of PEI, the adsorption effect is poor, resulting in a significant decrease in coating performance. The molecular structure of PSS has good rigidity, and the combination effect with PDDA is significant, which can form a uniform multilayer structure with stronger water resistance and wear resistance. In contrast, PAA has strong hygroscopicity, resulting in decreased water resistance and poor color stability. PTFE is extremely hydrophobic, providing the best waterproof protection for pigments. At the same time, its mechanical stability is better than other hydrophobic materials such as siloxane, ensuring better wear resistance and essential oil volatilization control.

[0168] 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 primer, characterized in that: The rose essential oil water-based two-component electrostatic spray solid color primer comprises component A and component B; The A group is composed of: Water-based hydroxy polyurethane emulsion: 30-40 parts by weight Deionized water: 15-25 parts by weight Inorganic pigment: 15-20 parts by weight Dispersant: 1-2 parts by weight Leveling agent: 0.5-1 parts by weight Defoaming agent 0.5-0.8 parts by weight Preservatives: 0.5-1 parts by weight Rose essential oil: 0.5-1 parts by weight Group B is composed of: 10-15 parts by weight of polyisocyanate; 3-5 parts by weight of film-forming aid.

2. A rose essential oil water-based two-component electrostatic spray solid color primer according to claim 1, characterized in that: The inorganic pigment is prepared by the following process steps: Pigment pretreatment: Disperse the pigment in a solution and charge its surface; First layer cationic polyelectrolyte deposition: depositing the first layer in a cationic polyelectrolyte solution; Washing the pigment: Wash the pigment with deionized water to remove the unadsorbed polyelectrolyte; Second layer anionic polyelectrolyte deposition: Deposit the second layer in anionic polyelectrolyte solution; Repeated deposition of multiple layers: alternating deposition of cationic and anionic layers to form a multilayer structure; Final encapsulation layer: Deposit the final encapsulation layer using a hydrophobic material; Drying and curing: Dry at appropriate temperature to ensure pigment stability.

3. A rose essential oil water-based two-component electrostatic spray solid color primer according to claim 1, characterized in that: The cationic polyelectrolyte is selected from one or more of polydiallyldimethylammonium chloride, polyethyleneimine, chitosan and polyurethane.

4. A rose essential oil water-based two-component electrostatic spray solid color primer according to claim 1, characterized in that: The anionic polyelectrolyte is selected from one or more of sodium polystyrene sulfonate, sodium polyacrylate, sodium carboxymethyl cellulose and sodium alginate.

5. A rose essential oil water-based two-component electrostatic spray solid color primer according to claim 1, characterized in that: The hydrophobic material is selected from one or more of polytetrafluoroethylene, perfluoroalkyl phosphate, paraffin fluoride and polyvinyl fluoride.

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

7. A rose essential oil water-based two-component electrostatic spray solid color primer 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 primer according to claim 1, characterized in that: The polyisocyanate comprises: HDI trimer 10-30 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 primer, characterized in that: The rose essential oil water-based two-component electrostatic spray solid color primer comprises component A and component B; The A group is composed of: Water-based hydroxy polyurethane emulsion: 30-40 parts by weight Deionized water: 15-25 parts by weight Inorganic pigment: 15-20 parts by weight Dispersant: 1-2 parts by weight Leveling agent: 0.5-1 parts by weight Defoaming agent 0.5-0.8 parts by weight Preservatives: 0.5-1 parts by weight Rose essential oil: 0.5-1 parts by weight Group B is composed of: 10-15 parts by weight of polyisocyanate; 3-5 parts by weight of film-forming aid; 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 primer.

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