CN101974143B - Organic silicon modified epoxy acrylate aqueous dispersion and preparation method thereof - Google Patents

Abstract

The invention discloses an organic silicon modified epoxy acrylate aqueous dispersion and a preparation method thereof. The method is to use polyether type epoxy diluent and epoxy resin to compound, and then react with acrylic acid monomer to obtain low viscosity epoxy acrylate prepolymer; then use maleic anhydride to graft it Introduce a hydrophilic group on the molecular chain; finally, compound a small molecule amino silicone oil and an organic base to make a neutralizer, neutralize the system, add water to dilute and disperse, adjust the solid content and viscosity, and obtain a UV-curable Aqueous dispersion of silicone modified epoxy acrylate. The silicone-modified epoxy acrylate aqueous dispersion has a high solid content of more than 60% and a low viscosity of 1,500-5,500 mPa.s. The coating film cured by ultraviolet light has a high hardness of 4H-6H, good flexibility and excellent water resistance, and the water absorption rate is as low as 5.0%. It can be used in furniture, construction, household appliances, paper printing and other fields.

Description

A kind of organosilicon modified epoxy acrylate aqueous dispersion and preparation method thereof

technical field

The invention relates to an aqueous dispersion of silicone-modified epoxy acrylate, in particular to a high-solid-content, low-viscosity UV-curable silicone-modified epoxy acrylate aqueous dispersion and a preparation method thereof.

Background technique

Ultraviolet (UV) curing technology is widely used in many fields such as paints, coatings, inks and adhesives because of its high efficiency, environmental protection and energy saving. With people's concern about the environment, the formulation and implementation of regulations to limit and reduce volatile organic compound (VOC) emissions, UV-curable coatings are gradually replacing traditional solvent-based coatings. The general formulation of UV-curable coatings includes photoinitiators, reactive monomers and photosensitive prepolymers, namely epoxy acrylates, urethane acrylates, acrylates (polyether or polyester) and unsaturated polyesters. Among them, epoxy acrylic resin has a wide range of raw materials, low price, and the main chain contains stable C-C bonds, benzene rings and ether bonds, and has good chemical resistance, tensile modulus, mechanical properties, etc. The main matrix resin of photocurable coatings. However, conventional epoxy acrylate prepolymers often have shortcomings such as excessive viscosity, hard and brittle film formation, and poor flexibility. It becomes a potential source of environmental pollution. Therefore, in the process of preparing UV-curable coatings, attempts have been made to replace active monomers with environmentally friendly solvent "water", and water-based ultraviolet (UV) curing technology has emerged since then. This technology combines the advantages of traditional UV curing technology and water-based coating technology, and has become a main direction for the development of UV curing coatings. However, with the hydrophilic modification of photosensitive resin and the addition of environmentally friendly solvents, some negative effects will appear on the performance of the coating film. For example, adding too much environmentally friendly solvent will affect the drying and curing speed, and the existence of hydrophilic groups will lead to water resistance. Poor and other problems limit its application in many industries. With the increasing pressure on resources and the environment, it is necessary to continuously improve the performance of environmentally friendly water-based photocurable epoxy acrylate resins to expand their application fields.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of high viscosity, high brittleness, poor flexibility and poor water resistance in the prior art, and provide a UV-curable epoxy acrylate with high solid content, low viscosity, excellent mechanical properties and water resistance Aqueous dispersions and methods for their preparation.

The purpose of the present invention is achieved through the following technical solutions:

A preparation method of silicone-modified epoxy acrylate aqueous dispersion, comprises the steps:

(1) Preparation of low-viscosity epoxy acrylate prepolymer: add epoxy resin, polyether type epoxy diluent and polymerization inhibitor into the container; stir and heat up to 70-75°C, add acrylic acid and catalyst dropwise, 0.5 The dropwise addition is completed in ~1h; then the temperature is raised to 80°C~90°C, and the reaction is carried out for 3~5h. When the acid value of the measurement system is lower than 5mgKOH/g, the reaction is stopped, and the epoxy acrylate modified by polyether epoxy diluent for viscosity reduction is obtained. prepolymer;

The epoxy resin is bisphenol A epoxy resin E-51, E-54 or E-44; the polyether epoxy diluent is polyethylene glycol diglycidol with a number average molecular weight of 550-650 Ether, one or both of polypropylene glycol diglycidyl ether and trimethylolpropane triglycidyl ether with a number average molecular weight of 550-750; The molar ratio of the carboxyl group of acrylic acid is 1:1; the epoxy molar ratio of the epoxy resin and the polyether type epoxy diluent is 2:1～1:2; 0.2% to 0.4% of the total mass of oxygen diluent and acrylic acid; the amount of catalyst is 0.5% to 0.8% of the total mass of epoxy resin, epoxy diluent and acrylic acid;

(2) Preparation of maleic anhydride grafted epoxy acrylate prepolymer: cooling the reaction system in step (1) to 50-60°C, adding maleic anhydride, catalyst and polymerization inhibitor, and stirring evenly; Using segmental heating method, react at 50-60°C for 0.5-1h, then raise the temperature to 70-80°C for 0.5-1h, stop when the reaction reaches the theoretical acid value, and obtain maleic anhydride grafted epoxy acrylate with carboxyl group in the side chain Prepolymer; the molar dosage of the maleic anhydride is 40% to 60% of the side hydroxyl molar content in the epoxy acrylate prepolymer obtained in step (1);

The amount of the catalyst and the polymerization inhibitor is respectively 0.5% to 0.8% and 0.2% to 0.4% of the total mass of the epoxy acrylate prepolymer in step (1);

(3) Preparation of silicone-modified epoxy acrylate aqueous dispersion: cool down the reaction system in step (2) to 40-50°C, add a polymerization inhibitor, and continue stirring; compound organic base and small molecule amino silicone oil into a neutralizing agent, the side chain prepared in step (2) has a carboxyl maleic anhydride grafted epoxy acrylate prepolymer for neutralization, and the degree of neutralization is 60% to 100%; add deionized water, and Dilute and emulsify and disperse under stirring to obtain an aqueous dispersion of silicone-modified epoxy acrylate with a solid content of 60% to 90%;

The organic base is dimethylaminoethanol or triethylamine; the number average molecular weight of the amino silicone oil is 100 to 400; the amount of the organic base is 60% to 100% of the molar amount of maleic anhydride; the amino silicone oil and polymerization inhibitor The agent dosage is respectively 1.0%～2.0% and 0.1～0.4% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer in the step (2);

The polymerization inhibitor of described step (1)～(3) is p-methoxyphenol, hydroquinone or 2,6-di-tert-butyl p-cresol; The step (1) and step (2) The catalyst is tetraethylammonium bromide or N,N-dimethylbenzylamine.

To further realize the purpose of the present invention, the theoretical acid value is defined as the system acid value when a maleic anhydride molecule retains a carboxyl group after ring-opening esterification.

The amount of the deionized water is preferably such that the solid content of the silicone-modified epoxy acrylate aqueous dispersion is controlled to 60%-80%.

The epoxy group molar ratio of the epoxy resin to the epoxy diluent is preferably 1:1.

A silicone-modified epoxy acrylate water dispersion is prepared by the above method.

The solid content of the silicone-modified epoxy acrylate aqueous dispersion is higher than 60%, and the viscosity is 1,500-5,500 mPa.s.

The solid content of the aqueous dispersion can be defined as the mass percentage of the non-aqueous part in the aqueous dispersion.

The preparation method of the present invention is to compound polyether type epoxy diluent and epoxy resin to reduce viscosity, and then carry out epoxy ring-opening esterification reaction with acrylic acid monomer, thereby introducing low modulus polyether into the prepolymer molecule chain segments to improve molecular mobility, so as to achieve the purpose of viscosity reduction and toughening modification; the esterification reaction of acrylic acid can introduce double bonds in the molecular chain, endowing the prepolymer with photosensitivity; and then use maleic anhydride and ring The side hydroxyl group generated after the ring opening of the epoxy resin undergoes a half-esterification reaction, introducing the hydrophilic carboxyl group into the molecular chain, and at the same time increasing the double bond content in the prepolymer; agent to neutralize the carboxyl groups in the prepolymer to obtain a low-viscosity UV-curable silicone-modified epoxy acrylate prepolymer; after the neutralization reaction, add deionized water dropwise to further adjust the solid content and viscosity, and Stir evenly to obtain a transparent or translucent high-solid-content, low-viscosity UV-curable silicone-modified epoxy acrylate aqueous dispersion.

The present invention adopts polyether type epoxy diluent to carry out viscosity reduction and toughening modification on bisphenol A type epoxy acrylate prepolymer and its aqueous dispersion, and can obtain higher solid content and lower construction viscosity at the same time , and improved the flexibility of the cured film.

The degree of dilution and emulsification dispersion of deionized water is related to the carboxyl content of the maleic anhydride grafted epoxy acrylate prepolymer, the degree of neutralization and the amount of deionized water. The higher the carboxyl content of the prepolymer, the greater the degree of neutralization , the better the compatibility with deionized water, the more transparent the aqueous dispersion is at lower solid content.

The viscosity and pre-drying time of the aqueous dispersion are related to the solid content, the smaller the solid content, the lower the viscosity, and the longer the pre-drying time.

The silicone-modified epoxy acrylate aqueous dispersion obtained in the present invention has the property of being curable by ultraviolet light, and the cured product has excellent mechanical properties and water resistance.

Compared with prior art, the present invention has following advantage:

(1) In view of the shortcomings of conventional epoxy acrylate prepolymers such as high viscosity, hard and brittle film formation and poor flexibility, the present invention adopts polyether type epoxy diluent to carry out viscosity reduction and toughening modification on it. After adding an appropriate proportion of polyether-type epoxy diluent, the initial viscosity of the epoxy resin compound system, the viscosity of the epoxy acrylate prepolymer and the viscosity of the prepolymer system grafted with maleic anhydride and neutralized all have a significant difference. The viscosity reduction rate can be as high as 90% to 99%. The flexibility of the polyether-modified UV curable film can be increased from a bending diameter of more than 10mm to 1-2mm.

(2) The present invention aims at defects such as poor water resistance and poor mechanical properties of the photosensitive resin after viscosity-reducing modification, and adopts small-molecule amino silicone oil and organic base to compound as a neutralizer, and the carboxyl-modified photosensitive prepolymer The neutralization modification is carried out, so that the organic silicon chain segment is introduced into the resin structure, the water resistance of the cured resin film is obviously improved, and the water absorption rate can be reduced to below 5.0%.

(3) The preparation method of the present invention has the advantages of simple and convenient process, no pollution, environmental friendliness, high coating film quality, and wide application prospects. Electrical appliances, paper printing and other fields as well as environmentally friendly coatings, inks and adhesives industries.

Specific implementation method

The present invention will be further described below in conjunction with the examples, but the examples are not intended to limit the protection scope of the present invention.

Example 1

(1) Add 46.26g of epoxy resin E-51, 77.86g of polypropylene glycol diglycidyl ether with a number average molecular weight of 550 to 750 and 0.32g of inhibitor hydroquinone, and add it with a stirring paddle, a thermometer, and a thermostat. In the four-necked reaction flask of pressure funnel and condenser; 35.26g acrylic acid is packed in constant pressure funnel. Among them, the molar ratio of epoxy resin E-51 and epoxy group in polypropylene glycol diglycidyl ether is 1:1, and the molar ratio of carboxyl group of acrylic acid and epoxy resin compound system is 1:1. When the temperature of the system was raised to 75°C, 1.28g of catalyst tetraethylammonium bromide was added, and acrylic acid was added dropwise, and the dropwise addition was completed within 0.5h. Continue to raise the temperature to 85° C., the reaction ends when the acid value of the system is less than 5 mgKOH/g, and the temperature is lowered to obtain a viscosity-reduced modified epoxy acrylate prepolymer. The amount of polymerization inhibitor is 0.2% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether and acrylic acid; the amount of catalyst is 0.8% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether and acrylic acid.

(2) After the system cools down to 60°C, add 23.67g of maleic anhydride (maleic anhydride), 1.46g of catalyst tetraethylammonium bromide and 0.36g of polymerization inhibitor hydroquinone, stir for 0.5h, then heat up To 75°C, when the reaction reaches a theoretical acid value of 75.80mgKOH/g, lower the temperature and terminate the reaction. Wherein, the molar dosage of maleic anhydride is 50% of the side hydroxyl molar content of epoxy acrylate prepolymer, the catalyst dosage is 0.8% of the total mass of epoxy acrylate prepolymer and maleic anhydride, and the polymerization inhibitor dosage is epoxy acrylate 0.2% of the total mass of the ester prepolymer and maleic anhydride, the theoretical acid value is the acid value of the system after the maleic anhydride and the epoxy acrylate prepolymer are half-esterified.

(3) After the system cools down to 50°C, add 0.36g of polymerization inhibitor hydroquinone and 15.00g of organic base neutralizing agent dimethylaminoethanol to carry out neutralization reaction. After stirring for 30 minutes, 21.22 g of deionized water was added to adjust the solid content and system viscosity to obtain a high solid content, low viscosity UV-curable epoxy acrylate aqueous dispersion with a yellow-brown transparent viscous appearance. Wherein, the degree of neutralization of the system is 70%, the solid content is 90%, and the amount of the polymerization inhibitor is 0.2% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer.

(4) add reactive diluent tripropylene glycol diacrylate in the epoxy acrylate aqueous dispersion of step (3) gained, photoinitiator 2-hydroxyl-2-methyl-1-phenyl-1-acetone (light Initiator 1173), stir evenly, apply film, and pre-bake in an oven at 60°C for 20 minutes, and then irradiate with a 2KW ultraviolet lamp for 5s to obtain an epoxy acrylate cured film. Wherein, the amount of the photoinitiator is 4% of the total mass of the epoxy acrylate water dispersion and the reactive diluent, and the mass ratio of the reactive diluent to the maleic anhydride grafted epoxy acrylate prepolymer is 2:8.

After testing, the compounding of epoxy diluent polypropylene glycol diglycidyl ether and epoxy resin E-51 reduced the initial viscosity from 6,220mPa·s to 114mPa·s, and the viscosity reduction rate was 98.17%. The system viscosity of epoxy acrylate prepolymer dropped from 35,080mPa·s to 1,340mPa·s, and the viscosity reduction rate was 96.16%; The viscosity of the corresponding prepolymer system modified by viscosity reduction is as high as 100,000mPa·s or more. When diluted with water to 90% solid content, the viscosity of the aqueous dispersion dropped to 6,410mPa.s, indicating that the addition of epoxy diluent greatly reduced the viscosity of the system. After UV curing, the pencil hardness of the coating film is 4H, the adhesion is grade 2, the impact performance is 30Kg·cm, and the bending performance is 2mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 11.30%.

Example 2

(1) 46.26g of epoxy resin E-51, 77.86g of polypropylene glycol diglycidyl ether with a number average molecular weight of 550 to 750 and 0.48g of inhibitor p-methoxyphenol were added with stirring paddle, thermometer, In a four-necked reaction flask with a constant pressure funnel and a condenser; 35.26 g of acrylic acid was charged into the constant pressure funnel. Among them, the molar ratio of epoxy resin E-51 and epoxy group in polypropylene glycol diglycidyl ether is 1:1, and the molar ratio of carboxyl group of acrylic acid and epoxy resin compound system is 1:1. When the temperature of the system was raised to 75° C., 0.80 g of catalyst N,N-dimethylbenzylamine was added, and acrylic acid was added dropwise, and the dropwise addition was completed within 0.5 h. Continue to raise the temperature to 85° C., the reaction ends when the acid value of the system is less than 5 mgKOH/g, and the temperature is lowered to obtain a viscosity-reduced modified epoxy acrylate prepolymer. The amount of polymerization inhibitor is 0.3% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether and acrylic acid; the amount of catalyst is 0.5% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether and acrylic acid.

(2) After the system cools down to 60°C, add 23.67g maleic anhydride, 0.91g catalyst N,N-dimethylbenzylamine and 0.54g polymerization inhibitor p-methoxyphenol, stir for 0.5h, then heat up to 75°C When the reaction reaches a theoretical acid value of 75.80 mgKOH/g, the temperature is lowered to terminate the reaction. Wherein, the molar dosage of maleic anhydride is 50% of the side hydroxyl molar content of epoxy acrylate prepolymer, the catalyst dosage is 0.5% of the total mass of epoxy acrylate prepolymer and maleic anhydride, and the polymerization inhibitor dosage is epoxy acrylate 0.3% of the total mass of ester prepolymer and maleic anhydride, the theoretical acid value is the acid value of the system after maleic anhydride and epoxy acrylate prepolymer undergo half-esterification.

(3) After the system cools down to 50°C, add 0.36g of polymerization inhibitor p-methoxyphenol and 15.00g of organic base neutralizing agent dimethylaminoethanol to carry out neutralization reaction. After stirring for 30 minutes, 21.22 g of deionized water was added to adjust the solid content and system viscosity to obtain a high solid content, low viscosity UV-curable epoxy acrylate aqueous dispersion, which appeared as light yellow transparent mucus. Wherein, the degree of neutralization of the system is 70%, the solid content is 90%, and the amount of the polymerization inhibitor is 0.2% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer.

(4) Add reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate in the epoxy acrylate aqueous dispersion of step (3) gained, photoinitiator 2-hydroxyl-2-methyl-1 -Phenyl-1-acetone (photoinitiator 1173), stir evenly, apply film, and pre-bake in an oven at 60°C for 30min, and then irradiate with 2KW UV lamp for 5s to obtain a cured epoxy acrylate film. Wherein, the amount of photoinitiator is 4% of the total mass of epoxy acrylate aqueous dispersion and reactive diluent, reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate and maleic anhydride grafted epoxy acrylate The mass ratio of the prepolymer is 1:1:8.

Compared with Example 1, the curing speed of the photosensitive prepolymer in this example is accelerated, and the degree of crosslinking is increased. After UV curing, the pencil hardness of the coating film is 5H, the adhesion is grade 2, the impact performance is 35Kg cm, and the bending performance It is 3mm, indicating that the cured film has higher hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 9.15%.

Example 3

(1) 46.26g of epoxy resin E-51, 72.47g of polyethylene glycol diglycidyl ether with a number average molecular weight of 550 to 650 and 0.31g of inhibitor p-methoxyphenol were added with stirring paddle, In the four-necked reaction flask of thermometer, constant pressure funnel and condenser; 35.26g acrylic acid is charged in constant pressure funnel. Among them, the molar ratio of epoxy resin E-51 and epoxy group in polypropylene glycol diglycidyl ether is 1:1, and the molar ratio of carboxyl group of acrylic acid and epoxy resin compound system is 1:1. When the temperature of the system was raised to 75°C, 1.23g of catalyst N,N-dimethylbenzylamine was added, and acrylic acid was added dropwise, and the dropwise addition was completed within 0.5h. Continue to raise the temperature to 85° C., the reaction ends when the acid value of the system is less than 5 mgKOH/g, and the temperature is lowered to obtain a viscosity-reduced modified epoxy acrylate prepolymer. The amount of polymerization inhibitor is 0.2% of the total mass of epoxy resin E-51, polyethylene glycol diglycidyl ether and acrylic acid; the amount of catalyst is the total mass of epoxy resin E-51, polyethylene glycol diglycidyl ether and acrylic acid 0.8%.

(2) After the system cools down to 60°C, add 23.67g maleic anhydride, 1.42g catalyst N,N-dimethylbenzylamine and 0.36g polymerization inhibitor p-methoxyphenol, stir for 0.5h, then heat up to 75°C When the reaction reaches a theoretical acid value of 77.25mgKOH/g, the temperature is lowered to terminate the reaction. Wherein, the molar dosage of maleic anhydride is 50% of the side hydroxyl molar content of epoxy acrylate prepolymer, the catalyst dosage is 0.8% of the total mass of epoxy acrylate prepolymer and maleic anhydride, and the polymerization inhibitor dosage is epoxy acrylate 0.2% of the total mass of the ester prepolymer and maleic anhydride, the theoretical acid value is the acid value of the system after the maleic anhydride and the epoxy acrylate prepolymer are half-esterified.

(3) After the system cools down to 50°C, add 0.36g of polymerization inhibitor p-methoxyphenol and 15.00g of organic base neutralizing agent dimethylaminoethanol to carry out neutralization reaction. After stirring for 30 minutes, 42.08 g of deionized water was added to adjust the solid content and system viscosity to obtain a high solid content, low viscosity UV-curable epoxy acrylate aqueous dispersion, which appeared as light yellow transparent mucus. Wherein, the degree of neutralization of the system is 70%, the solid content is 80%, and the amount of the polymerization inhibitor is 0.2% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer.

(4) Add reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate in the epoxy acrylate aqueous dispersion of step (3) gained, photoinitiator 2-hydroxyl-2-methyl-1 -Phenyl-1-acetone (photoinitiator 1173), stir evenly, apply film, and pre-bake in an oven at 60°C for 30min, and then irradiate with 2KW UV lamp for 5s to obtain a cured epoxy acrylate film. Wherein, the amount of photoinitiator is 4% of the total mass of epoxy acrylate aqueous dispersion and reactive diluent, reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate and maleic anhydride grafted epoxy acrylate The mass ratio of the prepolymer is 1:1:8.

After testing, the compounding of epoxy diluent polyethylene glycol diglycidyl ether and epoxy resin E-51 reduced the initial viscosity from 6,220mPa·s to 65mPa·s, and the viscosity reduction rate was 98.88%. The viscosity of the epoxy acrylate prepolymer decreased from 35,080mPa·s to 780mPa·s, and the viscosity reduction rate was 97.76%; the viscosity of the system modified by maleic anhydride was 7,150mPa·s, while The viscosity of the corresponding prepolymer system without viscosity reduction modification is as high as 100,000mPa·s or more. When diluted with water to 80% solid content, the viscosity of the aqueous dispersion dropped to 2,650mPa.s, indicating that the addition of epoxy diluent and part of water greatly reduced the viscosity of the system. After UV curing, the pencil hardness of the coating film is 4H, the adhesion is grade 1, the impact performance is 42Kg·cm, and the bending performance is 2mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 12.70%.

Example 4

(1) 46.26g of epoxy resin E-51, 38.95g of polypropylene glycol diglycidyl ether with a number average molecular weight of 550 to 750, 24.82g of trimethylolpropane triglycidyl ether and 0.44g of polymerization inhibitor Oxyphenol was added in a four-necked reaction flask with a stirring paddle, a thermometer, a constant pressure funnel and a condenser; 35.26g of acrylic acid was packed into the constant pressure funnel. Among them, the molar ratio of epoxy resin E-51 to polypropylene glycol diglycidyl ether and trimethylol propane triglycidyl ether is 1:0.5:0.5, and the carboxyl group of acrylic acid and epoxy resin compound system The epoxy group molar ratio is 1:1. When the temperature of the system was raised to 75°C, 0.73g of catalyst N,N-dimethylbenzylamine was added, and acrylic acid was added dropwise, and the dropwise addition was completed within 0.5h. Continue to raise the temperature to 85° C., the reaction ends when the acid value of the system is less than 5 mgKOH/g, and the temperature is lowered to obtain a viscosity-reduced modified epoxy acrylate prepolymer. The amount of polymerization inhibitor is 0.3% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether and acrylic acid; the amount of catalyst is epoxy resin E-51, polypropylene glycol diglycidyl ether 0.5% of the total mass of glyceryl ether, trimethylolpropane triglycidyl ether and acrylic acid.

(2) After the system cools down to 60°C, add 28.40g maleic anhydride, 0.87g catalyst N,N-dimethylbenzylamine and 0.52g polymerization inhibitor p-methoxyphenol, stir for 0.5h, then heat up to 75°C When the reaction reaches a theoretical acid value of 94.50mgKOH/g, the temperature is lowered to terminate the reaction. Wherein, the molar dosage of maleic anhydride is 60% of the side hydroxyl molar content of epoxy acrylate prepolymer, the catalyst dosage is 0.5% of the total mass of epoxy acrylate prepolymer and maleic anhydride, and the polymerization inhibitor dosage is epoxy acrylate 0.3% of the total mass of ester prepolymer and maleic anhydride, the theoretical acid value is the acid value of the system after maleic anhydride and epoxy acrylate prepolymer undergo half-esterification.

(3) After the system cools down to 50°C, add 0.35g of polymerization inhibitor p-methoxyphenol and 15.50g of organic base neutralizing agent dimethylaminoethanol to carry out neutralization reaction. After stirring for 30 minutes, 126.13 g of deionized water was added to adjust the solid content and system viscosity to obtain a high solid content, low viscosity UV-curable epoxy acrylate aqueous dispersion, which appeared as a light yellow translucent colloid. Wherein, the degree of neutralization of the system is 60%, the solid content is 60%, and the amount of the polymerization inhibitor is 0.2% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer.

(4) Add reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate in the epoxy acrylate aqueous dispersion of step (3) gained, photoinitiator 1-hydroxyl-cyclohexyl-phenylmethanol Ketone (photoinitiator 184), stir evenly and apply a film, and pre-baked in an oven at 60°C for 40 minutes, and then irradiated with a 2KW ultraviolet lamp for 5s to obtain a cured epoxy acrylate film. Wherein, the amount of photoinitiator is 4% of the total mass of epoxy acrylate aqueous dispersion and reactive diluent, reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate and maleic anhydride grafted epoxy acrylate The mass ratio of the prepolymer is 1:1:8.

After testing, the epoxy diluent polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether and epoxy resin E-51 compounded the system from the initial viscosity of 6,220mPa s to 350mPa s, and the viscosity reduction rate was 94.37%; the viscosity of the epoxy acrylate prepolymer modified by viscosity reduction dropped from 35,080mPa·s to 3,120mPa·s, and the viscosity reduction rate was 91.11%; and then modified by maleic anhydride The viscosity of the system is 32,610mPa·s, while the viscosity of the corresponding prepolymer system without viscosity reduction modification is as high as 100,000mPa·s or more. When diluted with water to 60% solid content, the viscosity of the aqueous dispersion dropped to 2,950 mPa.s. It can be seen that although the addition of the trifunctional epoxy diluent trimethylolpropane triglycidyl ether will increase the viscosity of the prepolymer system, after dilution to a lower solid content, the viscosity can still be reduced to below 3000mPa.s. After UV curing, the pencil hardness of the coating film is 6H, the adhesion is grade 2, the impact performance is 33Kg·cm, and the bending performance is 4mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 8.90%.

Example 5

(1) 46.26g of epoxy resin E-51, 77.86g of polypropylene glycol diglycidyl ether with a number average molecular weight of 550 to 750 and 0.48g of polymerization inhibitor 2,6-di-tert-butyl p-cresol were added with In a four-necked reaction flask with a stirring paddle, a thermometer, a constant pressure funnel and a condenser; 35.26g of acrylic acid was charged into the constant pressure funnel. Among them, the molar ratio of epoxy resin E-51 and epoxy group in polypropylene glycol diglycidyl ether is 1:1, and the molar ratio of carboxyl group of acrylic acid and epoxy resin compound system is 1:1. When the temperature of the system was raised to 75° C., 0.80 g of catalyst N,N-dimethylbenzylamine was added, and acrylic acid was added dropwise, and the dropwise addition was completed within 0.5 h. Continue to raise the temperature to 85° C., the reaction ends when the acid value of the system is less than 5 mgKOH/g, and the temperature is lowered to obtain a viscosity-reduced modified epoxy acrylate prepolymer. The amount of polymerization inhibitor is 0.3% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether and acrylic acid; the amount of catalyst is 0.5% of the total mass of epoxy resin E-51, polypropylene glycol diglycidyl ether and acrylic acid.

(2) After the system cools down to 60°C, add 18.94g maleic anhydride, 0.89g catalyst N,N-dimethylbenzylamine and 0.53g polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and stir for 0.5h , and then the temperature was raised to 75°C, and the temperature was lowered when the reaction reached a theoretical acid value of 75.80 mgKOH/g to terminate the reaction. Wherein, the molar dosage of maleic anhydride is 40% of the side hydroxyl molar content of epoxy acrylate prepolymer, the catalyst dosage is 0.5% of the total mass of epoxy acrylate prepolymer and maleic anhydride, and the polymerization inhibitor dosage is epoxy acrylate 0.3% of the total mass of ester prepolymer and maleic anhydride, the theoretical acid value is the acid value of the system after maleic anhydride and epoxy acrylate prepolymer undergo half-esterification.

(3) After the system cools down to 50°C, add 0.36g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, mix 15.65g of organic base triethylamine and 3.56g of amino silicone oil with a number average molecular weight of 100 to prepare It can be used as a neutralizing agent and added to the maleic anhydride grafted epoxy acrylate prepolymer for neutralization reaction. After stirring for 30 minutes, 49.38 g of deionized water was added to adjust the solid content and system viscosity to obtain a high solid content, low viscosity UV-curable epoxy acrylate aqueous dispersion, which appeared as a light yellow translucent colloid. Wherein the solid content is 80%, the organic base neutralization degree of the system is 80%, the amino silicone oil accounts for 2.0% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer, and the amount of the polymerization inhibitor is maleic anhydride grafted epoxy acrylate 0.2% of the total mass of the ester prepolymer.

(4) Add reactive diluent tripropylene glycol diacrylate and trimethylol propane triacrylate in the organosilicon-modified epoxy acrylate prepolymer of step (3) gained, photoinitiator 1-hydroxyl-cyclohexyl -Phenyl ketone (photoinitiator 184), after stirring evenly, coat the film, pre-bake it in an oven at 60°C for 30 minutes, and then irradiate it with a 2KW ultraviolet lamp for 5 seconds to obtain a cured epoxy acrylate film. Wherein, the amount of photoinitiator is 4% of the total mass of organosilicon-modified epoxy acrylate prepolymer and reactive diluent, reactive diluent tripropylene glycol diacrylate and trimethylolpropane triacrylate and maleic anhydride graft The mass ratio of the epoxy acrylate prepolymer is 1:1:8.

Compared with Examples 1 and 2, the viscosity of the epoxy acrylate prepolymer in this example increased from 10,840 mPa·s to 18,540 mPa·s after silicone modification. When diluted with water to 80% solid content, the viscosity of the aqueous dispersion dropped to 5,270mPa.s, indicating that the addition of epoxy diluent greatly reduced the viscosity of the system. After UV curing, the pencil hardness of the coating film is 5H, the adhesion is grade 2, the impact performance is 38Kg·cm, and the bending performance is 3mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 3.05%, showing excellent water resistance.

Example 6

The reaction process is basically the same as in Example 5. Wherein, 15.65g organic base triethylamine and 3.56g number average molecular weight in step (3) are the amino silicone oil of 100 with 17.60g organic base triethylamine and 1.78g number average molecular weight being the amino silicone oil of 100, other raw materials The corresponding ratio remains unchanged, and the dosage is adjusted accordingly.

Compared with Example 5, the viscosity of the epoxy acrylate prepolymer in this example increased from 10,840 mPa·s to 13,100 mPa·s after silicone modification. When diluted with water to 80% solid content, the viscosity of the aqueous dispersion drops to 3,250 mPa.s. After UV curing, the pencil hardness of the coating film is 5H, the adhesion is grade 1, the impact performance is 43Kg·cm, and the bending performance is 2mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 3.90%, showing excellent water resistance.

Example 7

The reaction process is basically the same as in Example 6. Wherein, 46.26g epoxy resin E-51 in the step (1) is replaced with 44.69g epoxy resin E-54, and the corresponding proportioning of other raw materials remains unchanged, and consumption is adjusted accordingly.

Compared with Example 6, the viscosity of the epoxy acrylate prepolymer in this example increased from 7,350 mPa·s to 8,620 mPa·s after silicone modification. When diluted with water to 80% solid content, the viscosity of the aqueous dispersion dropped to 2,100mPa.s, indicating that the initial viscosity of epoxy resin E-54 was low, and the final synthetic silicone modified epoxy acrylate aqueous dispersion The viscosity can be as low as about 2,000mPa.s. After UV curing, the pencil hardness of the coating film is 6H, the adhesion is grade 2, the impact performance is 40Kg·cm, and the bending performance is 3mm, indicating that the cured film has higher hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 3.30%, showing excellent water resistance.

Example 8

The reaction process is basically the same as in Example 6. Wherein, the 46.26g epoxy resin E-51 in the step (1) is replaced with 54.96g epoxy resin E-44, and the corresponding proportioning of other raw materials remains unchanged, and consumption is adjusted accordingly.

Compared with Example 6, the viscosity of the epoxy acrylate prepolymer in this example increased from 21,540 mPa·s to 25,060 mPa·s after silicone modification. When diluted with water to 80% solid content, the viscosity of the aqueous dispersion dropped to 9,850mPa.s, indicating that the initial viscosity of epoxy resin E-44 was higher, and the final synthetic silicone modified epoxy acrylate aqueous dispersion The viscosity is still close to about 10,000mPa.s. When diluted with water to 60% solid content, the viscosity of the aqueous dispersion can be reduced to 4,120mPa.s. After UV curing, the pencil hardness of the coating film is 4H, the adhesion is grade 1, the impact performance is 48Kg·cm, and the bending performance is 1mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), and the water absorption rate is 4.60%, showing excellent water resistance.

Example 9

Same as embodiment 8 reaction process. Wherein, 54.96g epoxy resin E-44 and 77.86g number average molecular weight in the step (1) are 550～750 polypropylene glycol diglycidyl ethers and use 36.39g epoxy resin E-44 and 103.59g number average molecular weight to be 550-750 polypropylene glycol diglycidyl ether, that is, the molar ratio of epoxy resin E-44 to epoxy group in polypropylene glycol diglycidyl ether is changed from 1:1 to 1:2, and the corresponding ratio of other raw materials remains No change, the dosage is adjusted accordingly.

Compared with Example 8, the system viscosity of the silicone-modified epoxy acrylate prepolymer in this example decreased from 25,060 mPa·s to 12,160 mPa·s. When diluted with water to 80% solid content, the viscosity of the aqueous dispersion dropped to 3,510mPa.s, indicating that increasing the amount of polypropylene glycol diglycidyl ether can greatly reduce the viscosity of the silicone-modified epoxy acrylate aqueous dispersion. After UV curing, the pencil hardness of the coating film is 4H, the adhesion is grade 1, the impact performance is 50Kg·cm, and the bending performance is 1mm, indicating that the cured film has high hardness and good flexibility. The cured film has no change after soaking in distilled water at 25°C for 24 hours (no discoloration, no foaming, no falling off), the water absorption rate is 4.85%, and it still has excellent water resistance.

Claims (5)

1. a preparation method of organosilicon modified epoxy acrylate aqueous dispersion, it is characterized in that comprising the steps: (1) Preparation of low-viscosity epoxy acrylate prepolymer: add epoxy resin, polyether type epoxy diluent and polymerization inhibitor into the container; stir and heat up to 70-75°C, add acrylic acid and catalyst dropwise, 0.5 The dropwise addition is completed in ~1h; then the temperature is raised to 80°C~90°C, and the reaction is carried out for 3~5h. When the acid value of the measurement system is lower than 5mgKOH/g, the reaction is stopped, and the epoxy acrylate modified by polyether epoxy diluent for viscosity reduction is obtained. prepolymer; The epoxy resin is bisphenol A epoxy resin E-51, E-54 or E-44; the polyether epoxy diluent is polyethylene glycol diglycidol with a number average molecular weight of 550-650 Ether, one or both of polypropylene glycol diglycidyl ether and trimethylolpropane triglycidyl ether with a number average molecular weight of 550-750; The molar ratio of the carboxyl group of acrylic acid is 1:1; the epoxy molar ratio of the epoxy resin and the polyether type epoxy diluent is 2:1～1:2; 0.2% to 0.4% of the total mass of oxygen diluent and acrylic acid; the amount of catalyst is 0.5% to 0.8% of the total mass of epoxy resin, epoxy diluent and acrylic acid; (2) Preparation of maleic anhydride grafted epoxy acrylate prepolymer: cooling the reaction system in step (1) to 50-60°C, adding maleic anhydride, catalyst and polymerization inhibitor, and stirring evenly; Using segmental heating method, react at 50-60°C for 0.5-1h, then raise the temperature to 70-80°C for 0.5-1h, stop when the reaction reaches the theoretical acid value, and obtain maleic anhydride grafted epoxy acrylate with carboxyl group in the side chain Prepolymer; the molar dosage of the maleic anhydride is 40% to 60% of the side hydroxyl molar content in the epoxy acrylate prepolymer obtained in step (1); The amount of the catalyst and the polymerization inhibitor is respectively 0.5% to 0.8% and 0.2% to 0.4% of the total mass of the epoxy acrylate prepolymer in step (1); (3) Preparation of silicone-modified epoxy acrylate aqueous dispersion: cool down the reaction system in step (2) to 40-50°C, add a polymerization inhibitor, and continue stirring; compound organic base and small molecule amino silicone oil into a neutralizing agent, the side chain prepared in step (2) has a carboxyl maleic anhydride grafted epoxy acrylate prepolymer for neutralization, and the degree of neutralization is 60% to 100%; add deionized water, and Dilute and emulsify and disperse under stirring to obtain an aqueous dispersion of silicone-modified epoxy acrylate with a solid content of 60% to 90%; The organic base is dimethylaminoethanol or triethylamine; the number average molecular weight of the amino silicone oil is 100 to 400; the amount of the organic base is 60% to 100% of the molar amount of maleic anhydride; the amino silicone oil and polymerization inhibitor The agent dosage is respectively 1.0%～2.0% and 0.1～0.4% of the total mass of the maleic anhydride grafted epoxy acrylate prepolymer in the step (2); The polymerization inhibitor of described step (1)～(3) is p-methoxyphenol, hydroquinone or 2,6-di-tert-butyl p-cresol; The step (1) and step (2) The catalyst is tetraethylammonium bromide or N, N-dimethylbenzylamine; The theoretical acid value is the acid value of the system when one carboxyl group remains after the maleic anhydride molecule is ring-opened and esterified. 2. the preparation method of organosilicon-modified epoxy acrylate water dispersion according to claim 1, is characterized in that: the consumption of described deionized water is to make the solid of organosilicon-modified epoxy acrylate water dispersion The content is controlled to 60%～80%. 3. The preparation method of the silicone-modified epoxy acrylate aqueous dispersion according to claim 1, characterized in that: the epoxy molar ratio of the epoxy resin to the epoxy diluent is 1:1. 4. A silicone-modified epoxy acrylate aqueous dispersion is characterized in that it is prepared by the method according to claim 1. 5. The silicone-modified epoxy acrylate aqueous dispersion according to claim 4, characterized in that: the solid content of the silicone-modified epoxy acrylate aqueous dispersion is higher than 60%, and the viscosity is 1,500-5,500 mPa s. the