Cardanol / urushiol thermal polymer modified raw lacquer liquid and preparation method thereof

Abstract

The invention belongs to the technical field of raw lacquer materials, and particularly relates to anacardol and urushiol thermal polymer modified raw lacquer liquid and a preparation method thereof. The modified raw lacquer liquid is prepared by adding a cardanol / urushiol thermal polymer into a raw lacquer liquid and uniformly mixing, wherein the mixing mass ratio of the cardanol / urushiol thermal polymer to the raw lacquer liquid is (1: 0.25)-(1: 4). The anacardol and urushiol thermal polymer is prepared by mixing anacardol and urushiol according to a mass ratio of 3: 7-9: 1 and then heating at 160-200 DEG C for 3-40 hours. The modified raw lacquer liquid belongs to a whole bio-based product and is dried into a film through laccase catalytic polymerization, and the drying time is short. The preparation method is simple and easy to implement, no VOC (volatile organic compound) is discharged in the preparation and use processes, the environment-friendly effect is achieved, a product paint film is excellent in hardness, glossiness, flexibility and the like, the paint film is light in color, color paint is easy to prepare, and the paint can be applied to the field of industrial and civil coating.

Description

Technical Field

[0001] The invention belongs to the technical field of raw lacquer materials, and particularly relates to a raw lacquer liquid modified with a cardanol / urushiol thermal polymer and a preparation method thereof. Background Art

[0002] Lacquer sap is a water-in-oil (W / O) emulsion collected from the lacquer tree, which grows in Asian countries. Lacquer sap is primarily produced in China. As a natural coating, it has been used there for over 8,000 years. The film formation of lacquer differs from that of conventional synthetic coatings. While most synthetic coatings dry primarily due to solvent volatilization, the lacquer film forms through the synergistic action of multiple components within the lacquer, catalyzed by the enzyme laccase, through the polymerization of the monomer urushiol. Urushiol possesses multiple functional groups, including benzene rings, phenolic hydroxyl groups, and carbon-carbon double bonds on alkyl side chains, resulting in a highly cross-linked and dense film, endowed with a unique structure and excellent properties. Lacquer is known as the "king of coatings" for its excellent dry film properties, including high gloss, high hardness, strong corrosion resistance, and exceptional durability. However, lacquer films also have drawbacks, such as dark color, susceptibility to UV degradation, and poor alkali resistance. Furthermore, although China is a major producer of lacquer sap, actual production is very small, and lacquer is also very expensive. These factors limit its widespread application.

[0003] To reduce the price of raw lacquer and increase its availability, modifying it with inexpensive and readily available raw materials is a convenient approach. Cardanol, extracted from cashew nut shells, is a cheap and highly productive renewable resource. It is a substituted phenol with a 15-carbon side chain with 0-3 double bonds at the meta position. Its structure is similar to urushiol and can be polymerized by peroxidase. However, since it is not a substrate for lacquer, it is difficult for lacquer to be incorporated into the lacquer film.

[0004] The invention patent (publication number CN 103044643 A) discloses a bio-based urushiol-cardanol resin and its synthesis method. The bio-based resin is polymerized by cardanol, urushiol, formaldehyde (or furfural), and an organic solvent such as xylene, butanol, or cyclohexanone, along with a catalyst. Cobalt naphthenate, lead naphthenate, or manganese dioxide are added for curing. Although the resin can dry naturally and the paint film has excellent properties such as high hardness and strong water and chemical resistance, it emits VOCs during the synthesis and use process. In particular, residual formaldehyde and the leakage of heavy metals in the curing agent can cause ecological and environmental problems, which is not in line with current environmental protection policies.

[0005] The invention patent (publication number CN 105400426A) discloses a novel raw lacquer refined environmentally friendly paint and its production method. It is prepared using the traditional method of making refined raw lacquer. Raw lacquer, cardanol, natural turpentine and purified water are stirred at room temperature in air, and the lacquer phenol is oxidized and polymerized by laccase in the raw lacquer. Although the paint is environmentally friendly, since the added cardanol is not a substrate for laccase, a large amount of cardanol is only present in the environmentally friendly paint in the form of filler. The patent does not provide the final coating properties, but it can be inferred that the addition of cardanol will reduce the crosslinking degree and comprehensive properties of the original raw lacquer film, such as drying speed, hardness, heat resistance, etc. At present, there is no literature report on the research of introducing cardanol into raw lacquer and maintaining and improving the performance of the raw lacquer film. Summary of the Invention

[0006] To address the problems associated with the utilization of existing raw lacquer solutions and the modification of cardanol / urushiol thermal polymers, the present invention provides a method for preparing a raw lacquer solution modified with a cardanol / urushiol thermal polymer. The urushiol / urushiol thermal polymer of the present invention can be applied to raw lacquer solutions and oxidized by laccase to polymerize and dry, thus enabling its use in modifying raw lacquer. The cardanol / urushiol thermal polymer-modified raw lacquer solution can dry naturally. The modified lacquer solution with an optimized formula has a paint film performance comparable to that of raw lacquer solutions, but at a lower cost.

[0007] The technical means for achieving the purpose of the present invention are as follows:

[0008] A raw lacquer liquid modified by a cardanol / urushiol thermal polymer consists of a raw lacquer liquid and an urushiol / cardanol thermal polymer, wherein the composite mass ratio of the raw lacquer liquid to the urushiol / cardanol thermal polymer is 1:0.25 to 1:4.

[0009] The raw lacquer liquid is an emulsion collected by cutting lacquer from lacquer trees.

[0010] The urushiol / cardanol thermal polymer refers to a product obtained by heating and polymerizing a mixture of urushiol and cardanol.

[0011] The method for preparing the urushiol / cardanol thermal polymer comprises the following steps: uniformly mixing 30 to 90 parts by mass of urushiol and 70 to 10 parts by mass of cardanol, and heating the mixture at 160 to 200° C. for 3 to 40 hours.

[0012] The preparation method of the cardanol / urushiol thermal polymer modified raw lacquer liquid is as follows: adding urushiol / cardanol thermal polymer cooled to room temperature into the raw lacquer liquid, and stirring at room temperature at a speed of 300 rpm for 1 to 5 hours under nitrogen protection.

[0013] The beneficial effects of the present invention are:

[0014] The present invention thermally polymerizes cardanol and urushiol in the absence of a solvent to prepare an urushiol / cardanol thermal polymer. The thermal polymerization reaction primarily involves substitution of aromatic protons, a Diels-Alder cycloaddition reaction, and a slight ether formation reaction. The resulting thermal polymer retains the catechol groups of the urushiol and can be oxidized by Rhus verniciflua laccase to further polymerize into a film. The urushiol / cardanol thermal polymer is added to a raw lacquer solution to produce a cardanol / urushiol thermal polymer-modified raw lacquer solution. The thermal polymer can further polymerize with the urushiol in the raw lacquer solution under lacquerase catalysis, thereby achieving rapid drying of the paint film. The thermal polymer also retains the high degree of intermolecular crosslinking in the paint film, as well as the paint film's properties such as hardness, gloss, flexibility, and organic solvent resistance. The color of the paint film can also be lightened, thereby facilitating the preparation of colored raw lacquer. This not only reduces the cost of the raw lacquer solution but also expands its application. The polymerization process of the present invention is simple, environmentally friendly, and the reaction is easy to control and reproduce. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 These are photos of the original raw paint dry film (A) and the dry paint film prepared in Example 5 (B). DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0017] In the following examples, raw lacquer liquid was purchased from Lichuan Delong Raw Lacquer Technology Co., Ltd., and cardanol was purchased from Jinan Feifan Chemical Co., Ltd.

[0018] Example 1: 30g of urushiol and 70g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant-temperature oil bath at 160°C at 240 rpm for 7 hours to obtain a urushiol / cardanol thermopolymer. After the thermopolymer cooled to room temperature, it was added to a raw lacquer solution in a 4:1 weight ratio. The mixture was stirred at 300 rpm under nitrogen for 1 hour at room temperature to obtain a raw lacquer solution modified with the cardanol / urushiol thermopolymer.

[0019] Example 2: 50g of urushiol and 50g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant-temperature oil bath at 190°C under nitrogen at a rate of 300 rpm for 24 hours to produce a urushiol / cardanol thermopolymer. After the thermopolymer cooled to room temperature, it was added to a raw lacquer solution in a 2:1 weight ratio. The mixture was stirred at 300 rpm under nitrogen at room temperature for 4 hours to produce a raw lacquer solution modified with the cardanol / urushiol thermopolymer.

[0020] Example 3: 60g of urushiol and 40g of cardanol were added to a 250ml four-necked flask and heated in a constant-temperature oil bath at 200°C under nitrogen at a stirring rate of 300 rpm for 12 hours to obtain a urushiol / cardanol thermopolymer. After the thermopolymer cooled to room temperature, it was added to a raw lacquer solution in a 3:1 weight ratio. The mixture was stirred at 300 rpm under nitrogen at room temperature for 3 hours to obtain a raw lacquer solution modified with the cardanol / urushiol thermopolymer.

[0021] Example 4: 90g of urushiol and 10g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant-temperature oil bath at 170°C at 350 rpm for 3 hours to obtain a urushiol / cardanol thermopolymer. After the thermopolymer cooled to room temperature, it was added to a raw lacquer solution in a 1:2 weight ratio. The mixture was stirred at 300 rpm under nitrogen at room temperature for 5 hours to obtain a raw lacquer solution modified with the cardanol / urushiol thermopolymer.

[0022] Example 5: 50g of urushiol and 50g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant temperature oil bath at 190°C under nitrogen at a stirring rate of 300 rpm for 24 hours to obtain a urushiol / cardanol thermal polymer. After the thermal polymer cooled to room temperature, it was added to a raw lacquer solution in a 1:1 weight ratio. The mixture was stirred at 300 rpm under nitrogen at room temperature for 4 hours to obtain a raw lacquer solution modified with the cardanol / urushiol thermal polymer.

[0023] Example 6: 50g of urushiol and 50g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant temperature oil bath at 190°C under nitrogen at a stirring rate of 300 rpm for 24 hours to obtain a urushiol / cardanol thermal polymer. After the thermal polymer cooled to room temperature, it was added to a raw lacquer solution in a 1:2 weight ratio. The mixture was stirred at 300 rpm under nitrogen at room temperature for 4 hours to obtain a raw lacquer solution modified with the cardanol / urushiol thermal polymer.

[0024] Example 7: 40g of urushiol and 60g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant temperature oil bath at 190°C under nitrogen at a stirring rate of 200 rpm for 32 hours to obtain a urushiol / cardanol thermal polymer. After the thermal polymer cooled to room temperature, it was added to a raw lacquer solution in a mass ratio of 1:3. The mixture was stirred at 300 rpm under nitrogen at room temperature for 2 hours to obtain a raw lacquer solution modified with the cardanol / urushiol thermal polymer.

[0025] Example 8: 50g of urushiol and 50g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant-temperature oil bath at 180°C under nitrogen at a rate of 400 rpm for 40 hours to produce a urushiol / cardanol thermopolymer. After the thermopolymer cooled to room temperature, it was added to a raw lacquer solution in a 1:2 weight ratio. The mixture was stirred at 300 rpm under nitrogen at room temperature for 4 hours to produce a raw lacquer solution modified with the cardanol / urushiol thermopolymer.

[0026] Example 9: 50g of urushiol and 50g of cardanol were added to a 250ml four-necked flask, then heated and stirred in a constant temperature oil bath at 180°C under nitrogen at a stirring rate of 400 rpm for 40 hours to obtain a urushiol / cardanol thermal polymer. After the thermal polymer cooled to room temperature, it was added to a raw lacquer solution in a mass ratio of 1:4. The mixture was stirred at 300 rpm under nitrogen at room temperature for 4 hours to obtain a raw lacquer solution modified with cardanol / urushiol thermal polymer.

[0027] The cardanol / urushiol thermal polymer modified raw lacquer liquid prepared above was coated on a glass plate (20 cm × 20 cm) using an applicator with a wet film thickness of 75 μm. The drying time was measured using a QGZ-24 automatic paint film drying time tester (Tianjin Jianyi Testing Instrument Factory) at 30°C and 80% relative humidity. The paint was applied to a tinplate plate (7 cm × 15 cm) and dried at 30°C and 80% relative humidity for 5 months. The pencil hardness, gloss and flexibility of the paint film were tested using the methods of GB / T 6739-2006, GB / T 1743-1979 and GB / T 1731-2020. The color value was measured using an NR10QC colorimeter (Guangdong Sanenshi Technology Co., Ltd.). The test results are listed in Table 1.

[0028] Table 1 Performance test results of paint film

[0029]

[0030] The test results of paint film properties in Table 1 show that the addition of different mass ratios of cardanol / lacquer phenol thermal polymer to the raw lacquer emulsion can improve the drying performance and glossiness of the original raw lacquer film, and the flexibility of the paint film can be maintained or improved. The hardness of the paint films of some embodiments has decreased, but the paint films of most embodiments are consistent with the original raw lacquer films. In addition, the paint films of all embodiments are brighter and more colorful than the original raw lacquer films, and the color of the paint films is also lighter. The accompanying drawings of the specification provide photos of the original raw lacquer film and the dry film of Example 5. It can be seen from the figure that the modified raw lacquer film is lighter and more colorful than the original raw lacquer film.

[0031] The above are the embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A raw lacquer liquid modified with a cardanol / urushiol thermal polymer, characterized in that: The invention is composed of raw lacquer liquid and urushiol / cardanol thermal polymer, and the mass ratio of the raw lacquer liquid and urushiol / cardanol thermal polymer is 1:0.25 to 1:

4.

2. The cardanol / urushiol thermal polymer modified raw lacquer liquid according to claim 1, characterized in that: The raw lacquer liquid is an emulsion collected by cutting lacquer from lacquer trees.

3. The cardanol / urushiol thermal polymer modified raw lacquer liquid according to claim 1, characterized in that: The urushiol / cardanol thermal polymer is obtained by mixing urushiol and cardanol and heating and polymerizing them.

4. The cardanol / urushiol thermal polymer modified raw lacquer liquid according to claim 3, characterized in that: The mass ratio of urushiol to cardanol is 30-90:70-10.

5. A method for preparing the cardanol / urushiol thermal polymer modified raw lacquer solution according to claim 1, characterized in that: The method comprises the following steps: mixing raw lacquer liquid and urushiol / urushiol thermal polymer, stirring and reacting at a stirring speed in a protective gas atmosphere, and obtaining raw lacquer liquid modified with urushiol / urushiol thermal polymer after the reaction is completed.

6. The method for preparing the cardanol / urushiol thermal polymer modified raw lacquer solution according to claim 5, wherein: The method for preparing the urushiol / cardanol thermal polymer comprises the following steps: stirring and mixing urushiol and cardanol uniformly, then heating at a temperature ranging from 160 to 200° C. for a time ranging from 3 to 40 hours, and cooling to room temperature to obtain the urushiol / cardanol thermal polymer.

7. The method for preparing the cardanol / urushiol thermal polymer modified raw lacquer liquid according to claim 5, characterized in that: The stirring reaction temperature is room temperature, and the stirring reaction time is 1 to 5 hours.

8. The method for preparing the cardanol / urushiol thermal polymer modified raw lacquer liquid according to claim 5, wherein: The protective gas includes nitrogen.

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