Anti-aging anti-cracking water-based oil paint and preparation method thereof

Abstract

The invention belongs to the technical field of oil paints, and discloses an anti-aging and anti-cracking water-based oil paint, which is prepared from the following components in parts by mass: 15 to 30 parts of pigment, 15 to 25 parts of modified linseed oil, 30 to 55 parts of acrylic resin emulsion, 0.5 to 1 part of PH regulator, 0.5 to 1.5 parts of thickening agent, 1 to 3 parts of nano filler, 0.2 to 0.6 part of anti-aging agent, 0.1 to 0.3 part of preservative and 10 to 20 parts of water. The modified linseed oil is formed by carrying out graft modification on linseed oil and an acrylate monomer; the acrylic resin emulsion is a specific monomer copolymer. Through the synergistic compatibility of the acrylate modified linseed oil and the acrylic resin emulsion, and in combination with the nano filler and the composite anti-aging agent system, the pigment film has good flexibility, uniform film-forming property and structural stability under a thick coating condition, meanwhile, the oxidation resistance and yellowing resistance are improved, and the generation of cracks is effectively inhibited. The oil paint has both aging resistance and cracking resistance.

Description

An aging-resistant and crack-resistant water-based oil paint and its preparation method Technical Field

[0001] This invention belongs to the field of oil paint technology, specifically relating to an aging-resistant and crack-resistant water-based oil paint and its preparation method. Background Technology

[0002] As an important art material, oil paints directly affect the quality and lifespan of artworks through their long-term preservation performance and expressive power. Traditional oil paints often use drying oils (such as linseed oil and walnut oil) as film-forming mediums, which can form oil films with gloss and color saturation. However, in the process of realizing this invention, the inventors found that traditional oil paints have at least the following problems: (1) Insufficient aging resistance. When oil paintings are exposed to changes in air, light and humidity for a long time, the paint film is prone to oxidation and yellowing, affecting the color stability and appearance of the work. Especially in thick areas, the oxidation and shrinkage of the drying oil film generates stress, which can easily lead to cracking and peeling. (2) Poor crack resistance. When applying thick layers or large areas of paint, traditional oil paints generate large shrinkage stress during the drying process. The hardness and flexibility of the oil film do not match, which can easily lead to cracks. (3) Difficulty in water-based conversion. Existing water-based oil paints often have problems such as insufficient emulsion stability, uneven pigment dispersion, and brittle film formation, making it difficult to balance aging resistance, crack resistance and artistic expressiveness. Summary of the Invention

[0003] The present invention aims to at least partially solve the aforementioned technical problems. Therefore, the objective of the present invention is to provide an aging-resistant and crack-resistant water-based oil paint and its preparation method.

[0004] The technical solution adopted in this invention is as follows:

[0005] An aging-resistant and crack-resistant water-based oil paint comprises the following components in parts by weight: 15-25 parts modified linseed oil; 15-30 parts pigment; 30-55 parts acrylic resin emulsion; 0.5-1 part pH adjuster; 0.5-1.5 parts thickener; 1-3 parts nanofiller; 0.2-0.6 parts anti-aging agent; 0.1-0.3 parts preservative; and 10-20 parts water.

[0006] Preferably, the modified linseed oil is prepared by grafting linseed oil and acrylate monomers, wherein the acrylate monomers include ethyl acrylate, 2-ethylhexyl acrylate and hydroxyethyl acrylate.

[0007] More preferably, in the preparation of the modified linseed oil, the mass ratio of ethyl acrylate, 2-ethylhexyl acrylate, and hydroxyethyl acrylate is (20-35):(10-25):(1-5); the total mass ratio of the acrylate monomers to the linseed oil is (30-65):(80-120); and the initiator for the grafting reaction is azobisisobutyronitrile.

[0008] Preferably, the acrylic resin emulsion is a copolymer emulsion prepared by emulsion polymerization using methyl methacrylate, butyl acrylate, lauryl methacrylate and octadecyl methacrylate as monomers.

[0009] More preferably, in the preparation of the acrylic resin emulsion, the mass ratio of methyl methacrylate, butyl acrylate, lauryl methacrylate, and octadecyl methacrylate is (20-35):(10-15):(1-5):(1-5).

[0010] More preferably, in the preparation of the acrylic resin emulsion, the emulsifier used is Span 80 or OP-10, and the initiator used is one of ammonium persulfate, potassium persulfate, or 2,2'-azobis(2-methylpropylamidine) dihydrochloride.

[0011] Preferably, the nanofiller is one or more of nano-silica, nano-alumina, nano-calcium carbonate, or nano-titanium dioxide.

[0012] Preferably, the anti-aging agent is a mixture of 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole and Tinuvin 770, with a mass ratio of (1-3):(0.5-2):(2-5).

[0013] Preferably, the pH adjuster is triethanolamine, and the thickener is hydroxyethyl cellulose.

[0014] The present invention also provides a method for preparing the above-mentioned aging-resistant and crack-resistant water-based oil paint, comprising the following steps:

[0015] (a) The pigment is mixed and dispersed with water to obtain a pigment slurry;

[0016] (b) Disperse the anti-aging agent in heated modified linseed oil;

[0017] (c) Add the acrylic resin emulsion to the mixture of step (b) and stir to form an oil-emulsion premix;

[0018] (d) Add the pigment slurry from step (a) to the premixed solution from step (c), and adjust the pH value to 6-9 using a pH adjuster;

[0019] (e) Add thickener, nanofiller and preservative to the system in sequence, stir evenly and degas to obtain the final product.

[0020] The beneficial effects of this invention are as follows:

[0021] (1) This invention uses acrylate-modified linseed oil as the oil phase, which retains the film-forming properties of drying oil and forms a flexible oil film phase that can absorb the shrinkage stress generated during the drying process of the pigment film, thereby inhibiting the generation and propagation of cracks. The acrylic grafting unit reduces the exposure of easily oxidized double bonds in the oil and improves the oxidation resistance and yellowing resistance.

[0022] (2) The acrylic resin emulsion used in this invention is copolymerized from hard monomers (methyl methacrylate) and flexible long-chain monomers (butyl acrylate, lauryl methacrylate and octadecyl methacrylate), which constructs a film-forming structure that combines rigidity and flexibility, disperses the drying stress of thick coating and inhibits crack formation, and significantly enhances the aging resistance and crack resistance of oil paint.

[0023] (3) The present invention uses a composite anti-aging agent system, with 2,6-di-tert-butyl-p-cresol (BHT) and butylated hydroxyanisole (BHA) as hindered phenolic antioxidants, which, together with Tinuvin 770 light stabilizer, can effectively inhibit the oxidation and discoloration of oil paint film and photoaging, and extend the life of paint film.

[0024] (4) Experiments have shown that after the oil paints of the present invention are stored at room temperature for 180 days, the color difference ΔE is less than 0.30, the yellowing index ΔYi is less than 1.5, and no cracking occurs. Compared with the formulation using unmodified linseed oil or ordinary acrylic emulsion, the performance has achieved a technological leap. Detailed Implementation

[0025] The present invention will be further explained below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. All "parts" mentioned in the embodiments refer to parts by weight.

[0026] Preparation of core components:

[0027] 1. Preparation of modified linseed oil

[0028] A preferred method for preparing modified linseed oil is as follows:

[0029] (1) Add 80-120 parts of unmodified linseed oil to a clean three-necked flask and purge with nitrogen for 30 minutes to remove oxygen.

[0030] (2) Heat the reaction system to 90°C, add 30-65 parts of acrylate monomer mixture (where the mass ratio of ethyl acrylate, 2-ethylhexyl acrylate and hydroxyethyl acrylate is 20-35:10-25:1-5), adjust the speed to 350 rpm, and stir until uniform.

[0031] (3) Use a constant flow pump to slowly add the initiator azobisisobutyronitrile (the ratio of its addition to the mass of linseed oil is 0.1-0.3:80-120) at a rate of 1-3 mL / min, and continue the reaction in a nitrogen atmosphere for 4-6 hours to obtain modified linseed oil.

[0032] 2. Preparation of acrylic resin emulsion

[0033] A preferred method for preparing acrylic resin emulsion is as follows:

[0034] (1) Add 60-100 parts of deionized water to a clean three-necked flask and add emulsifier (Span 80 or OP-10) in proportion (0.3-0.8:60-100 by mass of water).

[0035] (2) Then add 30-60 parts of monomer mixture in total mass (the mass ratio of methyl methacrylate, butyl acrylate, lauryl methacrylate and octadecyl methacrylate is 20-35:10-15:1-5:1-5).

[0036] (3) A uniform and stable oil-in-water emulsion was formed by continuous shearing emulsification at 9000 rpm for 20 minutes on a high-speed shear emulsifier.

[0037] (4) Transfer the emulsion to a three-necked flask, heat it to the reaction temperature of 60-80℃, control the stirring speed at 350-450 rpm, and introduce nitrogen to remove oxygen.

[0038] (5) Add an initiator (ammonium persulfate, potassium persulfate or 2,2'-azobis(2-methylpropylamidine) dihydrochloride, the mass ratio of which to deionized water is 60-100:0.20-0.40), and continue the reaction in a nitrogen atmosphere for 6 hours to obtain an acrylic resin emulsion.

[0039] Example 1

[0040] The preparation of an aging-resistant and crack-resistant water-based oil paint includes the following steps:

[0041] (1) Add 20 parts of pigment (titanium dioxide) to a mixing container and slowly add 10 parts of water to wet it. Disperse the pigment under sand milling conditions to make its particle size uniform and obtain pigment slurry.

[0042] (2) Heat 15 parts of the modified linseed oil prepared by the above method in a reactor to 60°C, add 0.3 parts of anti-aging agent (a mixture of 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole and Tinuvin 770 in a mass ratio of 2:1:3), set the stirring speed to 2500 rpm, and make the anti-aging agent evenly dispersed.

[0043] (3) Slowly add 40 parts of the acrylic resin emulsion prepared by the above method to the modified linseed oil in step (2) while stirring to form a uniform oil-emulsion premix, and keep stirring for 15 minutes.

[0044] (4) Slowly add the dispersed pigment slurry from step (1) to the premixed solution from step (3) and stir to disperse evenly. Add 0.5 parts of pH adjuster (triethanolamine) to adjust the pH of the system to 8.

[0045] (5) Add 1.0 part thickener (hydroxyethyl cellulose) and 3 parts nano filler (nano silica) to the system, and keep the stirring speed at 2500 rpm to ensure full and uniform dispersion.

[0046] (6) Add 0.2 parts of preservative (Kathon™ CG) to the system and homogenize or lightly grind the final water-based pigment system. After stirring evenly, let the system stand to remove bubbles to obtain the finished product.

[0047] Examples 2-6

[0048] Referring to the method of Example 1, only the amount of each component is changed, and the specific formulation is as follows (unit: parts):

[0049] Components Example 2 Example 3 Example 4 Example 5 Example 6 Pigment 25 30 30 15 20 Water 15 15 15 15 15 Modified Linseed Oil 15 20 25 15 20 Anti-aging Agent 0.4 0.5 0.6 0.6 0.4 Acrylic Resin Emulsion 50 45 55 45 55 pH Adjuster 0.5 0.5 0.5 0.5 1 Thickener 10.8 0.8 1.5 1.5 Nanofiller 3 2.5 2.5 33 Preservative 0.2 0.2 0.2 0.2 0.2 surface

[0050] Comparative Examples 1-5

[0051] Comparative Example 1: Unmodified linseed oil was used instead of the modified linseed oil in Example 1, and the other components and proportions were the same as in Example 1.

[0052] Comparative Example 2: A commercially available ordinary pure acrylic emulsion was used instead of the special acrylic resin emulsion in Example 1, with other components and proportions being the same as in Example 1.

[0053] Comparative Example 3: Only modified linseed oil was used as the film-forming agent (total amount 55 parts), without using acrylic resin emulsion, and other components and proportions were the same as in Example 1.

[0054] Comparative Example 4: Only the acrylic resin emulsion of the present invention was used as the film-forming material (total amount 55 parts), without the use of modified linseed oil, and the other components and proportions were the same as in Example 1.

[0055] Comparative Example 5: BHT was used as the anti-aging agent (0.3 parts) to replace the composite anti-aging agent in Example 1, and the other components and proportions were the same as in Example 1.

[0056] Performance Testing: The oil paints of Examples 1-6 and Comparative Examples 1-5 were applied to canvases and left at room temperature for 180 days. The color difference (ΔE), yellowing index (ΔYi), and cracking grade were then tested. Yellowing index grading standards: Grade 0: ΔYi ≤ 1.5; Grade 1: 1.6 < ΔYi ≤ 3.0; Grade 2: 3.1 < ΔYi ≤ 6.0; Grade 3: 6.1 < ΔYi ≤ 9.0; Grade 4: 9.1 < ΔYi ≤ 12.0; Grade 5: ΔYi > 12.0. The results are shown in Tables 1 and 2.

[0057] Table 1. Pigment performance test results of the examples

[0058] Test Item Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Color Difference (△E) 0.28 0.24 0.21 0.17 0.19 0.15 Yellowing Index (△Yi) 1.5 1.3 1.2 0.9 1 0.8 Crack Grade No crack No crack No crack No crack No crack No crack No crack surface

[0059] Table 2. Performance test results of comparative pigments

[0060] Test Items Comparison 1 Comparison 2 Comparison 3 Comparison 4 Comparison 5 Color Difference (△E) 0.82 0.94 0.98 0.9 0.4 Yellowing Index (△Yi) 2.8 3.5 3.8 3.2 2.2 Crack Grade Medium Crack Severe Crack Severe Crack Severe Crack Medium Crack surface

[0061] As shown in Table 1, after all the oil paintings painted with pigments in the examples were placed at room temperature for 180 days, the color difference ΔE was less than 0.30, the yellowing index ΔYi was less than 1.5 (reaching level 0), and no obvious cracks were observed.

[0062] As shown in Table 2, if the linseed oil was not modified with acrylate (Comparative Example 1), or if the special acrylic resin emulsion of the present invention was not used (Comparative Example 2), or if the two did not work synergistically (Comparative Examples 3 and 4), the color difference increased significantly, the yellowing rate was fast, and severe cracking occurred. Compared with the composite anti-aging agent (Example 1), the anti-aging performance of the single anti-aging agent (Comparative Example 5) was also significantly worse.

[0063] The experimental results fully demonstrate that the present invention significantly enhances the crack resistance and aging resistance of oil paints through the synergistic effect of acrylate-modified linseed oil, special acrylic resin emulsion, and composite anti-aging agent. The combination of these technical features is essential to obtaining the beneficial effects of the present invention.

[0064] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A water-based oil paint that is resistant to aging and cracking, characterized in that, The product comprises the following components in parts by weight: 15-25 parts modified linseed oil; 15-30 parts pigment; 30-55 parts acrylic resin emulsion; 0.5-1 part pH adjuster; 0.5-1.5 parts thickener; 1-3 parts nanofiller; 0.2-0.6 parts anti-aging agent; 0.1-0.3 parts preservative; and 10-20 parts water.

2. The aging-resistant and crack-resistant water-based oil paint according to claim 1, characterized in that, The modified linseed oil is produced by grafting linseed oil and acrylate monomers, wherein the acrylate monomers include ethyl acrylate, 2-ethylhexyl acrylate and hydroxyethyl acrylate.

3. The aging-resistant and crack-resistant water-based oil paint according to claim 2, characterized in that, In the preparation of the modified linseed oil, the mass ratio of ethyl acrylate, 2-ethylhexyl acrylate, and hydroxyethyl acrylate is (20-35):(10-25):(1-5); the total mass ratio of the acrylate monomers to the linseed oil is (30-65):(80-120); and the initiator for the grafting reaction is azobisisobutyronitrile.

4. The aging-resistant and crack-resistant water-based oil paint according to claim 1, characterized in that, The acrylic resin emulsion is a copolymer emulsion prepared by emulsion polymerization using methyl methacrylate, butyl acrylate, lauryl methacrylate and octadecyl methacrylate as monomers.

5. The aging-resistant and crack-resistant water-based oil paint according to claim 4, characterized in that, In the preparation of the acrylic resin emulsion, the mass ratio of methyl methacrylate, butyl acrylate, lauryl methacrylate, and octadecyl methacrylate is (20-35):(10-15):(1-5):(1-5).

6. The aging-resistant and crack-resistant water-based oil paint according to claim 4, characterized in that, In the preparation of the acrylic resin emulsion, the emulsifier used is Span 80 or OP-10, and the initiator used is one of ammonium persulfate, potassium persulfate, or 2,2'-azobis(2-methylpropylamidine) dihydrochloride.

7. The aging-resistant and crack-resistant water-based oil paint according to claim 1, characterized in that, The nanofiller is one or more of nano-silica, nano-alumina, nano-calcium carbonate, or nano-titanium dioxide.

8. The aging-resistant and crack-resistant water-based oil paint according to claim 1, characterized in that, The anti-aging agent is a mixture of 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole and Tinuvin 770, with a mass ratio of (1-3):(0.5-2):(2-5).

9. The aging-resistant and crack-resistant water-based oil paint according to claim 1, characterized in that, The pH adjuster is triethanolamine, and the thickener is hydroxyethyl cellulose.

10. A method for preparing an aging-resistant and crack-resistant water-based oil paint as described in any one of claims 1-9, characterized in that, Includes the following steps: (a) Mix and disperse the pigment with water to obtain a pigment slurry; (b) Disperse the anti-aging agent in heated modified linseed oil; (c) Add the acrylic resin emulsion to the mixture in step (b) and stir to form an oil-emulsion premix; (d) Add the pigment slurry from step (a) to the premix in step (c) and adjust the pH value to 6-9 with a pH adjuster; (e) Add the thickener, nanofiller and preservative to the system in sequence, stir evenly, and then degas to obtain the final product.