Polyurethane coating with hydrophobicity and multiple curing performance and preparation method thereof

Abstract

The invention discloses a polyurethane coating with hydrophobicity and multiple curing performance and a preparation method of the polyurethane coating. Aliphatic diisocyanate and unsaturated dihydric alcohol are used as raw materials to prepare an unsaturated polyurethane prepolymer containing-NCO end groups, then a hydroxyl-terminated silane coupling agent synthesized through sulfydryl double bond reaction is added for sealing, and the polyurethane coating is prepared. A series of silane-terminated unsaturated polyurethane is obtained through reaction and can be used for preparing a polyurethane coating with hydrophobicity and multiple curing performance; polyurethane with the main chain being a carbon chain containing double bonds and the end group being silane is synthesized, rapid ultraviolet light hardening of the surface of the coating is achieved, the end group silane rapidly migrates to the surface, the interior of the coating is crosslinked through multiple curing, the hydrophobicity, the adhesive force, the surface strength and other performance of the coating are effectively improved, and the coating has the good application prospect. The method has potential application prospects in the fields of buildings, automobiles, aerospace and the like.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials and coatings, and in particular to a polyurethane coating with hydrophobicity and multiple curing properties and a preparation method thereof. Background Art

[0002] Polyurethane is generally a block copolymer obtained by the polyaddition reaction of polyol compounds and isocyanate compounds. As a type of coating, polyurethane coating has been widely used in the fields of industry, agriculture, transportation, aerospace, etc. due to its simple construction, recyclability, high gloss, excellent decorative properties, strong wear resistance, good adhesion, good weather resistance, corrosion resistance and mechanical properties.

[0003] In recent years, the development of super hydrophobic polyurethane coating has attracted wide attention, and its application in antifouling self-cleaning, oil spill treatment, protective coating, self-healing materials and sensors has great potential. Existing studies have reported that polysilane containing dihydroxy or polyhydroxy is mixed with other polyols, and then reacted with isocyanate to prepare polyurethane molecules with a large amount of -Si-O-Si-bond structures in the main chain. Thus, the phase separation of polysilane (PDMS) and isocyanate segments is utilized to promote the structure containing -Si-O-Si-bonds in its main chain to migrate to the surface of the coating, and the coating is given hydrophobicity and wear resistance by its hydrophobic properties. However, the introduction of a large amount of polysilane on the polyurethane main chain, although it is conducive to the migration of silicon atoms to the coating surface, will inevitably have an adverse effect on the performance (such as adhesion and mechanical properties) of the coating substrate.

[0004] Another method to improve the hydrophobicity of the coating is to introduce silane coupling agents with active hydrogen at both ends of the polyurethane molecular chain, such as mercaptosilane, aminosilane (KH550), etc. In this method, the silane introduced into the polyurethane end group can complete the wet curing through hydrolysis cross-linking and form a silica-like structure in the coating. However, due to the small content of the silane coupling agent, most of the silica structures are evenly embedded in the polymer matrix to form a hybrid material, and fail to migrate to the surface. Therefore, the contact angle and surface wear resistance of this type of polyurethane coating are limited. Summary of the invention

[0005] In view of the problems of poor surface hydrophobicity, insufficient adhesion, high coating viscosity and difficulty in flowing of existing polyurethane coatings, the present invention provides a polyurethane coating with hydrophobicity and multiple curing properties and a preparation method thereof. The coating is made of terminal silane unsaturated polyurethane as the main raw material.

[0006] The technical solution of the present invention is as follows:

[0007] A silane-terminated unsaturated polyurethane is prepared by the following method:

[0008] S1: Preparation of hydroxy-terminated silane

[0009] The hydroxyl-containing olefin compound, the mercaptosilane coupling agent and the catalyst are mixed, and stirred for reaction at 70° C. under nitrogen protection for 7 hours to obtain terminal hydroxyl silane;

[0010] The hydroxyl-containing olefin compound is selected from: hydroxyethyl acrylate, allyl alcohol, etc.;

[0011] The mercaptosilane coupling agent is γ-mercaptopropyltrimethoxysilane;

[0012] The catalyst is azobisisobutyronitrile;

[0013] Preferably, the mass ratio of the hydroxyl-containing olefin compound, the mercaptosilane coupling agent, and the catalyst is 3.7-7.4:12.5:0.2;

[0014] S2: Preparation of Silane-Terminated Unsaturated Polyurethane

[0015] Dissolve aliphatic diisocyanate, unsaturated diol and catalyst in a solvent, stir at 50°C for 2h under dry nitrogen to obtain an unsaturated polyurethane prepolymer containing -NCO terminal groups, add the terminal hydroxyl silane prepared by S1, continue to react at 60°C for 1h, cool to room temperature, and obtain a terminal silane unsaturated polyurethane (which can be directly used for the preparation of subsequent coatings);

[0016] The aliphatic diisocyanate is selected from: one of hexamethylene diisocyanate and isophorone diisocyanate;

[0017] The unsaturated diol is cis-2-butene-1,4-diol;

[0018] The catalyst is dibutyltin dilaurate;

[0019] The solvent is selected from: anhydrous acetone or N,N-dimethylformamide;

[0020] Preferably, the mass ratio of aliphatic diisocyanate, unsaturated diol, catalyst and terminal hydroxyl silane is 5:1.308-2.181:0.025:2;

[0021] The molar ratio of isocyanate group (-NCO) to hydroxyl group (-OH) in the reaction raw materials, ie, the R value, is preferably in the range of 1.2 to 2.

[0022] The silane-terminated unsaturated polyurethane of the present invention can be used to prepare a polyurethane coating with hydrophobicity and multiple curing properties.

[0023] Therefore, the present invention also relates to a polyurethane coating with hydrophobicity and multiple curing properties, which is prepared from terminal silane unsaturated polyurethane and benzoin dimethyl ether as raw materials.

[0024] A specific coating preparation method is, for example: mixing terminal silane unsaturated polyurethane and benzoin dimethyl ether, stirring at 60° C. for 30 minutes, pouring into a dry glass dish, first irradiating under ultraviolet light, and then placing in an oven to cure into a film;

[0025] The mass percentage of benzoin dimethyl ether in the raw material is 2.2-2.3%;

[0026] UV light exposure time 15 to 20 minutes;

[0027] Oven curing conditions: 80°C, 30min.

[0028] The polyurethane coating with hydrophobicity and multiple curing properties of the present invention has the following characteristics:

[0029] The coating has the characteristics of multiple curing, hydrophobic surface, high surface hardness and good adhesion; wherein, multiple curing includes but is not limited to thermal curing, UV curing and wet curing; the hydrophobic surface is formed by surface curing of the coating, and its surface water contact angle can be greater than 120°; the high surface hardness is also formed by surface curing of the coating, and its surface hardness can be greater than 4H; the good adhesion is achieved by constructing a gradient cross-linking structure of the coating, and its adhesion to the glass surface can be greater than 5A.

[0030] The beneficial effects of the present invention are:

[0031] 1. The polyurethane coating of the present invention has the characteristics of low viscosity before curing and good surface hardness and adhesion after curing, and can be applied to the spraying of various complex types of products.

[0032] 2. The present invention has developed polyurethane multiple curing with different reaction principles. Light curing is used to quickly set the system or achieve "surface drying", and then heat reaction or moisture reaction is used to cure the shadow or bottom part to completely achieve "solid drying" of the system, thereby achieving comprehensive curing of the conformal coating.

[0033] 3. The polyurethane coating of the present invention can promote the rapid migration of silane in the coating to the surface through the rapid "surface drying" of the coating, forming a gradient distribution coating in which silicon atoms are concentrated on the surface, thereby giving the coating surface good hydrophobicity and hardness.

[0034] 4. The polyurethane coating of the present invention can achieve the properties of hydrophobicity of the coating surface, hardness and good adhesion to the substrate by controlling the curing degree of the coating at different depths.

[0035] 5. The polyurethane coating of the present invention has the advantages of simple preparation process, low reaction temperature, low viscosity, low cost, etc., and has potential application prospects in the fields of construction, automobiles, aerospace, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 : Schematic diagram of the reaction route for preparing silane-terminated unsaturated polyurethane according to the present invention.

[0037] Figure 2 : Fourier transform infrared spectra of the hydroxysilane coupling agent of Example 1-4.

[0038] Figure 3 : Fourier transform infrared spectra of unsaturated polyurethane prepolymer and terminal silane unsaturated polyurethane of Example 3.

[0039] Figure 4 : Element distribution diagram of silicon element from the surface to the inside of the silane-terminated unsaturated polyurethane before and after drying in Example 3.

[0040] Figure 5 Example 3: Distribution diagram of bromine element from the surface to the inside of the silane-terminated unsaturated polyurethane before and after the surface is dried and the unsaturated bonds are dyed with bromine. DETAILED DESCRIPTION

[0041] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0042] In the following examples, the hardness is measured according to the national standard GB / T 6739-2006 using a QHQ-A hand-push pencil hardness tester (700±50g) on ​​different coating surfaces. A Zhonghua brand pencil of different hardness is inserted into the pencil hardness tester and fixed with a clip. The tip of the pencil is placed on the coating surface, and the test plate is pushed toward the operator for at least 7 mm. The scratch is observed. If a scratch exceeding 3 mm appears, the hardness of the pencil is reduced and the test is repeated until scratches exceeding 3 mm no longer appear. The hardest pencil hardness that does not cause scratches of 3 mm or more on the coating represents the pencil hardness of the coating.

[0043] Adhesion refers to the national standard ASTM D3359-17 standard test method for evaluating adhesion by tape test. The X-cut tape test is adopted. A pressure-sensitive tape of about 75 mm is used. The center of the tape is adhered to the intersection of the interface. The air is exhausted and adhered (90±30s). After the tape is quickly removed, check whether the cut area has fallen off from the substrate. The adhesion is rated: 5A no peeling or removal; 4A peeling or removal along the traces of the cut or its intersection; 3A removal of serrations up to 1.6 mm (1 / 16 in.) on both sides along the cut; 2A serration removal along most of the cuts up to 3.2 mm (1 / 8 in.) on both sides. 1A removal from most of the area under the tape; 0A removal outside the area of ​​X.

[0044] Example 1

[0045] Preparation of hydroxysilane: 7.4 g of hydroxyethyl acrylate, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0046] Preparation of terminal silane unsaturated polyurethane: 5.000 g of hexamethylene diisocyanate, 1.745 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0047] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the above-prepared terminal silane unsaturated polyurethane, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, irradiate under ultraviolet light for 20 minutes, and then put it in an oven at 80°C to cure for 30 minutes to form a film.

[0048] Example 2

[0049] Preparation of hydroxysilane: 7.4 g of hydroxyethyl acrylate, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0050] Preparation of terminal silane unsaturated polyurethane: 5.000 g of hexamethylene diisocyanate, 1.745 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0051] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the terminal silane unsaturated polyurethane prepared above, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, irradiate under ultraviolet light for 15 minutes, then put it in an oven at 80°C to cure for 30 minutes to form a film, and put the cured coating in a 60°C water bath for 1 hour.

[0052] Example 3

[0053] Preparation of hydroxysilane: 7.4 g of hydroxyethyl acrylate, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0054] Preparation of terminal silane unsaturated polyurethane: 5.000 g of hexamethylene diisocyanate, 1.745 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0055] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the above-prepared terminal silane unsaturated polyurethane, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, irradiate under ultraviolet light for 15 minutes, and then put into an oven at 80°C to cure for 30 minutes to form a film.

[0056] Example 4

[0057] Preparation of hydroxysilane: 7.4 g of hydroxyethyl acrylate, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0058] Preparation of terminal silane unsaturated polyurethane: 5.000 g of hexamethylene diisocyanate, 1.308 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0059] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the above-prepared terminal silane unsaturated polyurethane, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, irradiate under ultraviolet light for 15 minutes, and then put into an oven at 80°C to cure for 30 minutes to form a film.

[0060] Example 5

[0061] Preparation of hydroxysilane: 3.7 g of allyl alcohol, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0062] Preparation of terminal silane unsaturated polyurethane: 5.000 g of isophorone diisocyanate, 1.745 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0063] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the above-prepared terminal silane unsaturated polyurethane, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, irradiate under ultraviolet light for 15 minutes, and then put into an oven at 80°C to cure for 30 minutes to form a film.

[0064] Comparative Example 1

[0065] Preparation of PU prepolymer coating: 5.000g hexamethylene diisocyanate and 1.745 cis-2-butene-1,4-diol were added to a three-necked flask equipped with a magnetic stirrer and passed with dry nitrogen. 0.025g dibutyltin dilaurate was added as a catalyst and 30mL DMF was used as a solvent. The reaction was carried out at 50°C for 2h to obtain an NCO-terminated unsaturated polyurethane. 0.2g benzoin dimethyl ether was added to the above-prepared silane-terminated unsaturated polyurethane, mixed and stirred at 60°C for 30 minutes, poured into a pre-prepared dry glass dish with a diameter of 60mm, irradiated under ultraviolet light for 15 minutes, and then placed in an oven at 80°C for curing for 30 minutes to form a film.

[0066] The contact angle, adhesion and hardness of Comparative Example 1 are lower than those of Example 3. Figure 3 It can be seen that Example 3 has a peak at 1095 cm -1 There is a stretching vibration peak of Si-OC at , while Comparative Example 1 does not. Figure 4 It can be seen that the silane in Example 3 migrates and aggregates to the coating surface after curing. Therefore, due to the lack of silane components, the contact angle and surface hardness of Comparative Example 1 are lower than those of Example 3. On the other hand, the silane contained in Example 3 will form silanol groups after absorbing moisture in the air and hydrate with the hydroxyl groups on the surface of the attached object to form a strong chemical bond. Since Comparative Example 1 does not contain silane, its interaction with the attached object relies on the formation of hydrogen bonds or other strong interactions between the carbamate and the surface of the attached object. Therefore, the adhesion of Comparative Example 1 is also less than that of Example 3.

[0067] Comparative Example 2

[0068] Preparation of hydroxysilane: 7.4 g of hydroxyethyl acrylate, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0069] Preparation of terminal silane unsaturated polyurethane: 5.000 g of hexamethylene diisocyanate, 1.745 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0070] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the above-prepared terminal silane unsaturated polyurethane, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, and form a film directly without UV curing and thermal curing.

[0071] After film formation, the coating of Comparative Example 2 showed cracks and poor performance. The main reasons for the poor performance of Comparative Example 2 are the following three points: 1. The coating has not been cured by UV light to form a dense cross-linked layer on the surface of the coating to achieve rapid "surface drying" on its surface, and the solvent evaporation rate does not match the curing rate of the coating. The solvent contained in it causes surface cracks in the coating after rapid evaporation. 2. The silicon element of the coating that has not been cured by UV light and heat has not been able to migrate and enrich to the surface, and the silicon element is evenly distributed throughout the depth of the coating ( Figure 4 ). 3. Without UV curing and heat curing, the curing can only be completed by moisture curing with limited silane, and the coating has a low crosslinking degree and low strength. The above three factors all lead to the smaller surface hardness and weaker adhesion of Comparative Example 2 than that of Example 3.

[0072] Comparative Example 3

[0073] Preparation of hydroxysilane: 7.4 g of hydroxyethyl acrylate, 12.5 g of KH590 and 0.2 g of azobisisobutyronitrile (AIBN) were added to a three-necked flask equipped with a magnetic stirrer and a thermometer. The reaction was carried out at 70° C. with stirring for 7 h, and nitrogen was introduced throughout the process.

[0074] Preparation of terminal silane unsaturated polyurethane: 5.000 g of hexamethylene diisocyanate, 2.181 g of cis-2-butene-1,4-diol, and 0.025 g of dibutyltin dilaurate were added to 30 mL of N,N-dimethylformamide (DMF), stirred at 50 ° C for 2 h under dry nitrogen, and then 2 g of the above-synthesized silane coupling agent was added, reacted at 60 ° C for 1 h, and cooled to room temperature to stop the reaction.

[0075] Preparation of a polyurethane coating with hydrophobicity and multiple curing properties: Add 0.2 g of benzoin dimethyl ether to the terminal silane unsaturated polyurethane prepared above, mix and stir at 60°C for 30 minutes, pour into a pre-prepared dry glass dish with a diameter of 60 mm, irradiate under ultraviolet light for 15 minutes, and then put into an oven at 80°C to cure for 30 minutes to form a film.

[0076] After film formation, the coating of Comparative Example 3 showed cracks and poor performance. Compared with Example 3, the soft segment content of Comparative Example 3 is larger. Therefore, in the process of preparing the terminal silane unsaturated polyurethane, Comparative Example 3 requires a longer reaction time to complete the reaction. Under the same reaction time, there are more small molecular components that do not participate in the reaction or have a lower degree of reaction than Example 3. Therefore, when the terminal silane unsaturated polyurethane of Comparative Example 3 forms a coating, due to the large difference in the molecular weight of the components, the different consistencies and drying rates of the components, cracks and poor adhesion appear.

[0077] The film states of the silane-terminated unsaturated polyurethane coatings obtained in the examples and comparative examples and the experimental results are shown in Table 1 below.

[0078] Table 1

[0079]

Claims

1. A silane-terminated unsaturated polyurethane, characterized in that: Prepared as follows: S1: Preparation of hydroxy-terminated silane The hydroxyl-containing olefin compound, the mercaptosilane coupling agent and the catalyst are mixed, and stirred for reaction at 70° C. under nitrogen protection for 7 hours to obtain terminal hydroxyl silane; The hydroxyl-containing olefin compound is selected from: hydroxyethyl acrylate or allyl alcohol; The mercaptosilane coupling agent is γ-mercaptopropyltrimethoxysilane; The catalyst is azobisisobutyronitrile; S2: Preparation of Silane-Terminated Unsaturated Polyurethane Dissolve aliphatic diisocyanate, unsaturated diol and catalyst in a solvent, stir at 50°C for 2h under dry nitrogen to obtain an unsaturated polyurethane prepolymer containing -NCO terminal groups, add the terminal hydroxyl silane prepared by S1, continue to react at 60°C for 1h, and cool to room temperature to obtain a terminal silane unsaturated polyurethane; The aliphatic diisocyanate is selected from: one of hexamethylene diisocyanate and isophorone diisocyanate; The unsaturated diol is cis-2-butene-1,4-diol; The catalyst is dibutyltin dilaurate.

2. The silane-terminated unsaturated polyurethane according to claim 1, characterized in that In S1, the mass ratio of the hydroxyl-containing olefin compound, the mercaptosilane coupling agent, and the catalyst is 3.7-7.4:12.5:0.

2.

3. The silane-terminated unsaturated polyurethane according to claim 1, characterized in that In S2, the solvent is selected from: anhydrous acetone or N,N-dimethylformamide.

4. The silane-terminated unsaturated polyurethane according to claim 1, characterized in that In S2, the mass ratio of aliphatic diisocyanate, unsaturated diol, catalyst and terminal hydroxyl silane is 5:1.308-2.181:0.025:

2.

5. The silane-terminated unsaturated polyurethane according to claim 1, characterized in that The molar ratio of isocyanate group -NCO to hydroxyl group -OH in the reaction raw materials is in the range of 1.2 to 2.

6. A polyurethane coating having hydrophobicity and multiple curing properties, characterized in that: The invention is prepared from the silane-terminated unsaturated polyurethane according to any one of claims 1 to 5 and benzoin dimethyl ether as raw materials.

7. The method for preparing a polyurethane coating having hydrophobicity and multiple curing properties as claimed in claim 6, characterized in that: The preparation method is as follows: terminal silane unsaturated polyurethane and benzoin dimethyl ether are mixed, stirred at 60° C. for 30 minutes, poured into a dry glass dish, first irradiated under ultraviolet light, and then placed in an oven to cure into a film; The mass percentage of benzoin dimethyl ether in the raw material is 2.2-2.3%; UV light exposure time 15 to 20 minutes; Oven curing conditions: 80°C, 30min.

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