Preparation process of ultraviolet curing coating

Abstract

The invention relates to the technical field of ultraviolet curing coatings, and discloses a preparation process of an ultraviolet curing coating, which comprises unsaturated polyester resin containing styrene on a side chain, a reactive diluent, a photoinitiator, a dispersant and a defoaming agent. Unsaturated polyester resin with an active alkenyl functional group on a side chain is prepared, and the unsaturated polyester resin and an active diluent can be subjected to a cross-linking polymerization reaction under the action of an ultraviolet light initiator, so that the photocuring speed of the coating is increased, and the photocuring time is shortened; moreover, rigid benzene rings in aryl alkenyl of a side chain are crosslinked and polymerized to form a spatial network structure, so that the rigidity and the strength of a cured coating are enhanced, and the impact strength and the bending strength of the coating are improved.

Description

Technical Field

[0001] The invention relates to the technical field of ultraviolet light curing coatings, in particular to a preparation process of ultraviolet light curing coatings. Background Art

[0002] The main types of coatings include solvent-based coatings, water-based coatings, room temperature curing coatings, UV curing coatings, etc. Among them, UV curing coatings are green and environmentally friendly coatings with fewer volatile components, low curing temperature and low curing energy consumption. They are widely used in wood, paper, thermal sensitive alloys, etc.

[0003] Unsaturated polyester resin has excellent dielectric properties, high heat resistance, good chemical corrosion resistance, and is a coating with excellent comprehensive properties. The double bonds on its main chain can undergo copolymerization and crosslinking reactions with vinyl monomers, making the unsaturated polyester resin have broad application prospects in ultraviolet light curing coatings. However, the double bonds on its main chain have large steric hindrance, low activity, and poor ultraviolet light curing effect. The present invention aims to prepare an unsaturated polyester resin containing styrene in the side chain as the main component of ultraviolet light curing coatings, thereby increasing the curing speed of the coating, reducing the curing time, and enhancing the mechanical strength of the coating. Summary of the invention

[0004] The technical problem solved by the invention is: using unsaturated polyester resin containing styrene in the side chain as the main component of ultraviolet light curing coating, solving the problems of slow curing speed, long curing time and low mechanical strength of the coating.

[0005] The technical solution of the present invention is: A preparation process of an ultraviolet light-curing coating, the ultraviolet light-curing coating comprising the following components in parts by weight: 58-73 parts of an unsaturated polyester resin containing styrene in a side chain, 25-35 parts of an active diluent, 2-6 parts of a photoinitiator, 0.1-0.4 parts of a dispersant, and 0.2-0.6 parts of a defoamer; the preparation process of the ultraviolet light-curing coating is as follows: (1) Add the following monomers: maleic anhydride, phthalic anhydride, ethylene glycol, propylene glycol, propylene glycol-based styrene monomer, and catalyst triphenyl phosphite into the reaction bottle and mix well.

[0006] (2) Add the polymerization inhibitor hydroquinone to the above reaction flask, introduce nitrogen to react, cool to room temperature, and discharge the material to obtain an unsaturated polyester resin containing styrene in the side chain.

[0007] (3) An unsaturated polyester resin containing styrene in the side chain, a reactive diluent, a photoinitiator, a dispersant, and a defoaming agent are mixed to obtain a UV-curing coating.

[0008] Furthermore, the reactive diluent is one or more of trimethylolpropane triacrylate, tripropylene glycol diacrylate or pentaerythritol triacrylate.

[0009] Furthermore, the photoinitiator is one or more of 2-hydroxy-2-methylphenylacetone, 1-hydroxycyclohexylphenylketone, and benzoin dimethyl ether.

[0010] Furthermore, the molar ratio of maleic anhydride, phthalic anhydride, ethylene glycol, propylene glycol, and propylene glycol-based styrene monomer is 1:1.1-1.2:0.3-0.4:1.5-1.8:0.03-0.15.

[0011] Furthermore, the catalyst triphenyl phosphite is 0.02-0.03% of the total molar amount of the polymerized monomers.

[0012] Furthermore, the reaction process in (2) is: firstly heating to 160-170°C and reflux reaction for 1-2 h, then heating to 180-190°C and continuing the reaction until the acid value (KOH) is 60-90 mg / g, then evacuating the mixture and controlling the vacuum degree to ≦0.05 MPa, and continuing the reaction until the acid value (KOH) is 25-35 mg / g.

[0013] Furthermore, the preparation process of the propylene glycol-based styrene monomer is as follows: add ethanol, serinol, and 4-vinylbenzaldehyde into a reaction bottle, heat to 50-70°C for reaction for 4-12 hours, cool, concentrate, and recrystallize from ethyl acetate to obtain the propylene glycol-based styrene monomer.

[0014] Furthermore, the molar ratio of serinol to 4-vinylbenzaldehyde is 0.8-1.3:1.

[0015] The beneficial technical effect of the present invention is as follows: the present invention utilizes maleic anhydride, phthalic anhydride, ethylene glycol, propylene glycol-based styrene and the like as polymerization monomers to prepare an unsaturated polyester resin having an active alkenyl functional group in the side chain; compared with the alkenyl in the main chain, the alkenyl in the side chain has less steric hindrance and higher activity, and can react with an active diluent to undergo a cross-linking polymerization reaction under the action of an ultraviolet light initiator, thereby increasing the light curing speed of the coating and reducing the light curing time; and the rigid benzene ring in the aromatic alkenyl in the side chain undergoes cross-linking polymerization to form a spatial network structure, which is beneficial to enhancing the rigidity and strength of the cured coating and improving the impact strength and bending strength of the coating. DETAILED DESCRIPTION

[0016] In the following, only certain exemplary embodiments are briefly described. As those skilled in the art would realize, the described embodiments may be modified in various different ways without departing from the spirit or scope of the present invention. Example 1

[0017] Preparation process of propylene glycol-based styrene monomer: add 1 L of ethanol, 0.6 mol of serinol, and 0.5 mol of 4-vinylbenzaldehyde into a reaction bottle, heat to 70 °C for 4 h, cool, concentrate, and recrystallize from ethyl acetate to obtain propylene glycol-based styrene monomer.

[0018]

[0019] Preparation process of unsaturated polyester resin containing styrene in the side chain: add polymerization monomers: 3 mol of maleic anhydride, 3.3 mol of phthalic anhydride, 0.9 mol of ethylene glycol, 4.5 mol of propylene glycol, 0.09 mol of propylene glycol-based styrene monomer, and 2.4 mmol of catalyst triphenyl phosphite into a reaction bottle and mix well; Add 0.2 mmol of inhibitor hydroquinone to the above reaction bottle, introduce nitrogen, first heat to 160 ° C and reflux reaction for 2 h, then heat to 180 ° C and continue the reaction until the acid value (KOH) is 80 mg / g, then evacuate and control the vacuum degree ≦0.05 MPa, continue the reaction until the acid value (KOH) is 28 mg / g, cool to room temperature, discharge the material, and obtain an unsaturated polyester resin containing styrene in the side chain.

[0020] The preparation process of the UV-curing coating is as follows: 72 parts by weight of an unsaturated polyester resin containing styrene in the side chain, 25 parts by weight of a reactive diluent trimethylolpropane triacrylate, 2 parts by weight of a photoinitiator benzoin dimethyl ether, 0.2 parts by weight of a BYK-W909 dispersant, and 0.6 parts by weight of an EFKA-2720 defoamer are mixed to obtain a UV-curing coating. Example 2

[0021] Preparation process of propylene glycol-based styrene monomer: add 0.6 L ethanol, 0.4 mol serinol, and 0.5 mol 4-vinylbenzaldehyde into a reaction bottle, heat to 70 ° C and react for 8 hours, cool, concentrate, and recrystallize from ethyl acetate to obtain propylene glycol-based styrene monomer.

[0022] Preparation process of unsaturated polyester resin containing styrene in the side chain: add polymerization monomers: 3 mol of maleic anhydride, 3.3 mol of phthalic anhydride, 1 mol of ethylene glycol, 4.8 mol of propylene glycol, 0.12 mol of propylene glycol-based styrene monomer, and 3.1 mmol of catalyst triphenyl phosphite into a reaction bottle and mix well; Add 0.23 mmol of inhibitor hydroquinone to the above reaction bottle, introduce nitrogen, first heat to 170 ° C for reflux reaction for 1 h, then heat to 190 ° C to continue the reaction until the acid value (KOH) is 80 mg / g, then evacuate and control the vacuum degree ≦0.05 MPa, continue the reaction until the acid value (KOH) is 28 mg / g, cool to room temperature, discharge the material, and obtain an unsaturated polyester resin containing styrene in the side chain.

[0023] The preparation process of the UV-curing coating is as follows: 69 parts by weight of an unsaturated polyester resin containing styrene in the side chain, 28 parts by weight of an active diluent pentaerythritol triacrylate, 3 parts by weight of a photoinitiator 2-hydroxy-2-methylphenylacetone, 0.1 parts by weight of a BYK-W909 dispersant, and 0.6 parts by weight of an EFKA-2720 defoamer are mixed to obtain a UV-curing coating. Example 3

[0024] Preparation process of propylene glycol-based styrene monomer: add 1 L of ethanol, 0.65 mol of serinol, and 0.5 mol of 4-vinylbenzaldehyde into a reaction bottle, heat to 70 ° C for 4 h, cool, concentrate, and recrystallize from ethyl acetate to obtain propylene glycol-based styrene monomer.

[0025] Preparation process of unsaturated polyester resin containing styrene in the side chain: add polymerization monomers: 3 mol of maleic anhydride, 3.6 mol of phthalic anhydride, 1.2 mol of ethylene glycol, 4.5 mol of propylene glycol, 0.28 mol of propylene glycol-based styrene monomer, and 3.2 mmol of catalyst triphenyl phosphite into a reaction bottle and mix well; Add 0.25 mmol of inhibitor hydroquinone to the above reaction bottle, introduce nitrogen, first heat to 160 ° C and reflux reaction for 2 h, then heat to 185 ° C and continue the reaction until the acid value (KOH) is 80 mg / g, then evacuate and control the vacuum degree ≦0.05 MPa, continue the reaction until the acid value (KOH) is 28 mg / g, cool to room temperature, discharge the material, and obtain an unsaturated polyester resin containing styrene in the side chain.

[0026] The preparation process of the UV-curing coating is as follows: 65 parts by weight of an unsaturated polyester resin containing styrene in the side chain, 30 parts by weight of an active diluent tripropylene glycol diacrylate, 4 parts by weight of a photoinitiator 2-1-hydroxycyclohexyl phenyl ketone, 0.2 parts by weight of a BYK-W909 dispersant, and 0.5 parts by weight of an EFKA-2720 defoamer are mixed to obtain a UV-curing coating. Example 4

[0027] Preparation process of propylene glycol-based styrene monomer: add 1 L of ethanol, 0.65 mol of serinol, and 0.5 mol of 4-vinylbenzaldehyde into a reaction bottle, heat to 60 ° C and react for 8 h, cool, concentrate, and recrystallize from ethyl acetate to obtain propylene glycol-based styrene monomer.

[0028] Preparation process of unsaturated polyester resin containing styrene in the side chain: add polymerization monomers: 3 mol of maleic anhydride, 3.6 mol of phthalic anhydride, 1.2 mol of ethylene glycol, 5 mol of propylene glycol, 0.36 mol of propylene glycol-based styrene monomer, and 3.5 mmol of catalyst triphenyl phosphite into a reaction bottle and mix well; Add 0.28 mmol of inhibitor hydroquinone to the above reaction bottle, introduce nitrogen, first heat to 165 ° C for reflux reaction for 1 h, then heat to 180 ° C to continue the reaction until the acid value (KOH) is 80 mg / g, then evacuate and control the vacuum degree ≦0.05 MPa, continue the reaction until the acid value (KOH) is 28 mg / g, cool to room temperature, discharge the material, and obtain an unsaturated polyester resin containing styrene in the side chain.

[0029] The preparation process of the UV-curing coating is as follows: 61 parts by weight of an unsaturated polyester resin containing styrene in the side chain, 32 parts by weight of a reactive diluent trimethylolpropane triacrylate, 6 parts by weight of a photoinitiator 2-hydroxy-2-methylphenylacetone, 0.4 parts by weight of a BYK-W909 dispersant, and 0.4 parts by weight of an EFKA-2720 defoamer are mixed to obtain a UV-curing coating. Example 5

[0030] Preparation process of propylene glycol-based styrene monomer: add 1 L of ethanol, 0.6 mol of serinol, and 0.5 mol of 4-vinylbenzaldehyde into a reaction bottle, heat to 70 °C for 4 h, cool, concentrate, and recrystallize from ethyl acetate to obtain propylene glycol-based styrene monomer.

[0031] Preparation process of unsaturated polyester resin containing styrene in the side chain: add polymerization monomers: 3 mol of maleic anhydride, 3.6 mol of phthalic anhydride, 1 mol of ethylene glycol, 5.4 mol of propylene glycol, 0.45 mol of propylene glycol-based styrene monomer, and 4 mmol of catalyst triphenyl phosphite into a reaction bottle and mix well; Add 0.28 mmol of inhibitor hydroquinone to the above reaction bottle, introduce nitrogen, first heat to 165 ° C for reflux reaction for 1 h, then heat to 190 ° C to continue the reaction until the acid value (KOH) is 80 mg / g, then evacuate and control the vacuum degree ≦0.05 MPa, continue the reaction until the acid value (KOH) is 28 mg / g, cool to room temperature, discharge the material, and obtain an unsaturated polyester resin containing styrene in the side chain.

[0032] The preparation process of the UV-curing coating is as follows: 58 parts by weight of an unsaturated polyester resin containing styrene in the side chain, 35 parts by weight of a reactive diluent trimethylolpropane triacrylate, 6 parts by weight of a photoinitiator 2-hydroxy-2-methylphenylacetone, 0.1 parts by weight of a BYK-W909 dispersant, and 0.5 parts by weight of an EFKA-2720 defoamer are mixed to obtain a UV-curing coating.

[0033] Comparative Example 1 Preparation process of unsaturated polyester resin: add polymerization monomers: 3 mol of maleic anhydride, 3.3 mol of phthalic anhydride, 0.9 mol of ethylene glycol, 4.5 mol of propylene glycol, 0.09 mol of propylene glycol-based styrene monomer, and 2.5 mmol of catalyst triphenyl phosphite based on the total molar amount of polymerization monomers into a reaction bottle, and mix well; Add 0.2 mmol of inhibitor hydroquinone to the above reaction bottle, introduce nitrogen, first heat to 160 ° C and reflux reaction for 2 h, then heat to 180 ° C and continue the reaction until the acid value (KOH) is 80 mg / g, then evacuate and control the vacuum degree ≦0.05 MPa, continue the reaction until the acid value (KOH) is 28 mg / g, cool to room temperature, discharge the material, and obtain unsaturated polyester resin.

[0034] The preparation process of the UV-curable coating is as follows: 72 parts by weight of unsaturated polyester resin, 25 parts by weight of active diluent trimethylolpropane triacrylate, 2 parts by weight of photoinitiator benzoin dimethyl ether, 0.2 parts by weight of BYK-W909 dispersant, and 0.6 parts by weight of EFKA-2720 defoamer are mixed to obtain the UV-curable coating.

[0035] The UV-curable coating was cured in a UV curing machine with a light intensity of 1.2 mW / cm 2 , test the curing time.

[0036] After the coating is cured by UV light, it is made into standard specimens and its mechanical properties are tested by an impact tester and a servo universal material testing machine. The test results are shown in the following table:

[0037] The unsaturated polyester resin side chain prepared in the embodiment contains an alkenyl functional group with small steric hindrance and high activity. Under the action of an ultraviolet light initiator, it can undergo a cross-linking polymerization reaction with an active diluent, thereby increasing the photocuring speed of the coating and reducing the photocuring time; and the rigid benzene rings in the aromatic alkenyl groups of the side chain are cross-linked and polymerized to form a spatial network structure, which is beneficial to enhancing the rigidity and strength of the cured coating and improving the impact strength and bending strength of the coating.

[0038] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A process for preparing a UV-curable coating, characterized in that: The UV-curable coating comprises the following components in parts by weight: 58-73 parts of an unsaturated polyester resin containing styrene in the side chain, 25-35 parts of a reactive diluent, 2-6 parts of a photoinitiator, 0.1-0.4 parts of a dispersant, and 0.2-0.6 parts of a defoamer; the preparation process of the UV-curable coating is as follows: (1) Add polymerization monomers: maleic anhydride, phthalic anhydride, ethylene glycol, propylene glycol, propylene glycol-based styrene monomer, and catalyst triphenyl phosphite into a reaction bottle and mix well; (2) adding a polymerization inhibitor, hydroquinone, into the above reaction flask, introducing nitrogen to react, cooling to room temperature, and discharging the material to obtain an unsaturated polyester resin containing styrene in the side chain; (3) mixing an unsaturated polyester resin containing styrene in the side chain, a reactive diluent, a photoinitiator, a dispersant, and a defoaming agent to obtain a UV-curable coating; The preparation process of the propylene glycol-based styrene monomer is as follows: add ethanol, serinol, and 4-vinylbenzaldehyde into a reaction bottle, heat to 50-70° C., react for 4-12 hours, cool, concentrate, and recrystallize from ethyl acetate to obtain the propylene glycol-based styrene monomer; The molar ratio of serinol to 4-vinylbenzaldehyde is 0.8-1.3:

1.

2. The process for preparing the UV-curable coating according to claim 1, characterized in that: The reactive diluent is one or more of trimethylolpropane triacrylate, tripropylene glycol diacrylate or pentaerythritol triacrylate.

3. The process for preparing the UV-curable coating according to claim 1, characterized in that: The photoinitiator is one or more of 2-hydroxy-2-methylphenylacetone, 1-hydroxycyclohexylphenylketone, and benzoin dimethyl ether.

4. The process for preparing the UV-curable coating according to claim 1, characterized in that: The molar ratio of maleic anhydride, phthalic anhydride, ethylene glycol, propylene glycol and propylene glycol-based styrene monomer is 1:1.1-1.2:0.3-0.4:1.5-1.8:0.03-0.

15.

5. The process for preparing the UV-curable coating according to claim 1, characterized in that: The catalyst triphenyl phosphite is 0.02-0.03% of the total molar amount of the polymerization monomers.

6. The process for preparing the UV-curable coating according to claim 1, characterized in that: The reaction process in (2) is: firstly heat to 160-170°C and reflux for 1-2 h, then heat to 180-190°C and continue the reaction until the acid value (KOH) is 60-90 mg / g, then evacuate and control the vacuum degree ≤ 0.05 MPa, and continue the reaction until the acid value (KOH) is 25-35 mg / g.

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