CN106832220B - A kind of preparation of the epoxy acrylate of graphene graft modification and its application in photocureable coating - Google Patents

Abstract

The invention discloses a kind of preparation methods of the epoxy acrylate of graphene graft modification; graphene oxide with reacted again with acrylate, acid binding agent containing active group after acylation reaction; it is finally copolymerized again with epoxy resin, the epoxy acrylate of graphene graft modification is made.In addition, the invention also discloses the applications of the epoxy acrylate of graphene graft modification, and added with the polymer-modified photocureable coating.The present invention is by acylating agent by graphene oxide and acrylate in situ bonding; then it is copolymerized again with epoxy resin; make graphene oxide in situ bonding into polymer; both had effects that good dispersion helped emulsification; the dispersion stabilization incomparable with physical blending again, can be obviously improved the properties added with the polymer-modified coating of the graphene.

Description

A kind of preparation of graphene graft-modified epoxy acrylate and its application in photocurable coating material application

technical field

The invention belongs to the technical field of epoxy acrylate coatings, and in particular relates to a preparation method of a graphene graft-modified epoxy acrylate, and a light-curing coating added with the modified epoxy acrylate.

Background technique

Bisphenol A epoxy acrylate, as the main resin of UV light-curing corrosion-resistant coatings with the largest dosage, has the advantages of excellent corrosion resistance and rapid curing, and has good mechanical properties, so it is widely used in many industrial fields. However, the bisphenol A epoxy acrylate coating product has high viscosity, poor light aging resistance and yellowing resistance, and its cured product has a high crosslinking density, resulting in poor toughness and easy separation of the coating from the substrate. reduces its comprehensive performance ^{[1, 2]} .

Graphene with two-dimensional structure can remain stable in corrosive gas, liquid or high temperature environment due to its stable heterocyclic structure. Although the performance of graphene is excellent, the graphene oxide prepared by redox method has a tendency to agglomerate into large particles of graphite oxide due to the π-π stacking tendency in the solvent, so that it cannot be stably dispersed in water and polar organic solvents for a long time. middle. This agglomeration phenomenon seriously hinders the application of graphene in electronic devices, coating systems, and composite materials.

At present, the use of inorganic materials to improve the performance of bisphenol A epoxy acrylate coatings has developed rapidly, but the use of graphene, a star material, to modify bisphenol A epoxy acrylate is still rare. Among them, most of the reports on graphene-modified bisphenol A epoxy acrylate adopt the method of blending or solution intercalation. The blending modification method can indeed combine the mechanical properties of graphene materials with the corrosion resistance and fast curing properties of bisphenol A epoxy acrylate coatings, and play a synergistic role, but the blending modification method disperses Poor performance, graphene cannot be uniformly dispersed in bisphenol A epoxy acrylate. The dispersibility of graphene in epoxy acrylate is poor, and it is easy to agglomerate, and the overall performance of the obtained graphene-based epoxy acrylate coating is unsatisfactory. Wei and his collaborators prepared GO/EA by compounding graphene oxide and epoxy acrylate prepolymer. The tensile strength of the prepared product increased by 8.39%, and the flexural modulus decreased by 46.79% ^[3] . In this work, graphene oxide is mixed with epoxy acrylates in a blending manner, resulting in the final composite homogeneity still cannot be guaranteed.

[1] Zhang j y, Windall g, Boyd i w. UV curing of optical fiber coatings using excimer lamps[J]. Applied Surface Science, 2002, 186(1-4): 568-572.

[2] Sun Xingping, Wang Dehai. Research progress on the synthesis and application of epoxy acrylate [J]. Coating Industry, 2007, 37(11): 53-57.

[3] Wei Yanyan, Wang Hu. Study on the Properties of Graphene Modified UV Curing Bisphenol A Epoxy Acrylic Resin [J]. Coating Industry, 2016, 46(6): 12-27.

Invention content:

In order to solve the technical problems of easy agglomeration and unsatisfactory material properties after doping in the existing methods of graphene doping and modifying epoxy acrylate, the invention provides a graphene graft-modified epoxy acrylate. The preparation method aims to avoid graphene agglomeration and improve the performance of the doped material.

The invention also provides the application of the graphene graft-modified epoxy acrylate.

In addition, the present invention also includes a coating added with the graphene graft-modified epoxy acrylate described in the present invention, which aims to improve the impact resistance, adhesion, abrasion resistance and other properties of the coating.

A preparation method of a graphene graft-modified epoxy acrylate, comprising the following steps:

Step (1): graphene oxide reacts with acylating agent to obtain acylated graphene oxide;

Step (2): react the acylated graphene oxide, the acrylate containing an active group, and the acid binding agent to obtain the graphene-modified acrylate;

Step (3): the graphene-modified acrylate and epoxy resin are then copolymerized to obtain the graphene graft-modified epoxy acrylate.

In the present invention, the acylating agent is esterified with active groups such as hydroxyl and carboxyl groups of graphene oxide, so that acylation active groups (acylated graphene oxide) are bonded and modified on the surface of graphene oxide; Under the catalysis of the acid agent, the acylation active group modified on the surface of graphene reacts with the acrylate containing the active group, so that the graphene oxide and the acrylate are compounded, and the double bond compound bonded with the graphene oxide in situ is obtained. (Graphene-modified acrylate); then copolymerize graphene oxide-bonded acrylate with epoxy resin, so that graphene oxide is in-situ and uniformly bonded to the polymer main chain, thereby effectively avoiding graphene oxide. Agglomeration; effectively improve the performance of the modified epoxy acrylate coating added. In the present invention, the use of polymerizable graphene (graphene-modified acrylate) not only has good dispersing and emulsification effect, but also has incomparable dispersion stability in physical blending, so that the mechanical properties of epoxy acrylate light-curing coatings are improved. In particular, the adhesion is greatly improved.

In the present invention, the acylating agent can react with active groups such as hydroxyl, carboxyl and other active groups on the surface of graphene oxide, so that the surface of graphene oxide is modified with active acylating groups, and the acylation The group is, for example, an acid halide group, a sulfonyl halide group, a sulfinyl halide group, a phosphorus oxyhalide group, etc.; more preferably an acid chloride group, a sulfonyl chloride group, a sulfinyl chloride group, a phosphorus oxychloride group group, etc.

Preferably, the acylating agent is at least one of thionyl chloride, phosphorus trichloride and phosphorus pentachloride.

Further preferably, the acylating agent is thionyl chloride.

In the present invention, the graphene oxide can be prepared by an improved Hummers method.

In the present invention, the preparation of graphene oxide by the Hummers method is divided into three steps, namely a low temperature reaction stage (0-5° C.), a medium temperature reaction stage (35-40° C.) and a high temperature reaction stage (90-95° C.). After the reaction is completed, washing and post-treatment are required to obtain the desired product.

In the present invention, the preparation step of graphene oxide is preferably:

Step (a): low temperature reaction stage: 2.0-2.5 parts by weight of natural flake graphite (particle size 0.1um) and 1-1.25 parts by weight of sodium nitrate NaNO ₃ were added to the 500ml there-necked flask placed in the ice bath environment, and during the slow stirring process Add 55.2-110.4 parts by weight of concentrated sulfuric acid (95%-98%), add 6-7.5 parts by weight of potassium permanganate KMnO ₄ in batches after keeping for 30-40min, and continue to keep the ice bath for 1-2h after adding about ten minutes;

Step (b): medium temperature reaction stage: transfer the system to a constant temperature water bath device at 30-35°C, and keep the temperature for 3-6h; slowly add deionized water dropwise to the reaction system with a constant pressure funnel;

Step (c): high temperature reaction stage: rapidly increase the temperature of the water bath to 80-95 ° C, keep the temperature for one hour; then add deionized water dropwise with a constant pressure funnel and continue to increase the stirring speed, continue to stir for 5-10min and then add dropwise Deionized water; after the dropwise addition, slowly add hydrogen peroxide (≥30%);

Step (d): washing and post-processing: after the reaction is completed, directly use filter paper to suction filtration while hot, and transfer the brown-yellow filter cake to a beaker after suction filtration; add hydrochloric acid diluted with concentrated hydrochloric acid into the beaker, and keep the temperature at 80-95 ° C Continue suction filtration after stirring for about half an hour, and continue to add water to suction filtration until the suction filtration fails; transfer the product on the filter cake to a 500ml beaker; use a low-speed centrifuge at 3500-5000r/min for the product in the beaker, Centrifuge and wash for 10-15min/time until the pH value of the upper layer of the test centrifuge tube no longer decreases; transfer the lower layer of the centrifuge tube to a watch glass, and place it in a vacuum drying box at 50-60℃ until it is completely dry; The graphite oxide is ground into powder.

In step (1), the acylating agent is in excess relative to graphene oxide, and preferably, the ratio of the added volume of the acylating agent to the weight of graphene oxide is 0.07-0.15 mL/g.

Preferably, in step (1), the ratio of the added volume of thionyl chloride to the weight of graphene oxide is 0.07-0.15 mL/g.

Preferably, in step (1), the reaction temperature is 60-70° C., and the reaction time is 19-24 h.

After the acylation reaction in step (1) is completed, the remaining thionyl chloride is evaporated under reduced pressure; the product is washed with chloroform and then dispersed in a chloroform solution for subsequent use.

The prepared acylated graphene oxide is ultrasonically dispersed in chloroform to prepare a dispersion liquid with a concentration of 0.5-1 mg/ml.

Preferably, the ultrasonic time is 1 to 3 hours.

In the present invention, the acid binding agent is a compound known to those skilled in the art that can react with an acid, for example, a compound with tertiary ammonia, an inorganic base, and the like.

Preferably, the acid binding agent is pyridine and/or triethylamine.

Further preferably, the acid binding agent is pyridine.

In the present invention, the active group-containing acrylate is an acrylate containing active hydrogen that can react with an acylating group; preferably, the active group-containing acrylate is a hydroxyl group and/or Acrylates of primary amino groups.

In the step (2), the acylated graphene oxide obtained in the step (1) is subjected to an esterification or amidation reaction with an acrylate containing an active group under the catalysis of an acid binding agent to obtain a graphene-modified acrylic acid. ester.

For example, the active group contained in the active group-containing acrylate is OH, and the OH and the acylated group are subjected to an esterification reaction, and the graphene oxide and the acrylate are compounded in the form of an ester bond; for another example, The active group contained in the active group-containing acrylate is NH2, and an amidation reaction is performed through NH2 and an acylated group, and the graphene oxide and the acrylate are compounded through an amide bond.

Further preferably, in step (2), under the catalysis of acid binding agent, the acylated graphene oxide obtained in step (1) is reacted with acrylic acid ester containing active groups to react with alcoholic hydroxyl groups and acid chloride groups to obtain graphite Alkene Modified Acrylates.

Further preferably, the described acrylate containing active group is a compound having the structure of formula 1:

In formula 1, Y is a C1-5 hydrocarbon group; R is H or a methyl group.

Said Y is a branched or straight chain hydrocarbon group of C1-5.

More preferably, the active group-containing acrylate is at least one of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxy-n-butyl (meth)acrylate.

Most preferably, the active group-containing acrylate is hydroxyethyl methacrylate.

Preferably, in step (2), excess acid binding agent is added dropwise to the acylated graphene oxide and the acrylate containing active groups at a temperature lower than 2 °C; after the dropwise addition is completed, the temperature is raised to room temperature, and the reaction is continued for 1 to 3 hours . After the reaction, the graphene-modified acrylate is obtained by washing with distilled water and drying.

In step (3), the epoxy resin is dissolved in the reactive diluent, then the graphene-modified acrylate, catalyst and polymerization inhibitor obtained in step (2) are added and copolymerized at 115° C.-135° C. to obtain the product. The graphene graft-modified epoxy acrylate.

Preferably, in step (3), the acid value of the polymerization process control system is less than 4.5-5 mg KOH/g.

Preferably, in step (3), the catalyst is at least one of N,N-dimethylbenzylamine, triphenylphosphine and tetraethylammonium bromide.

Preferably, in step (3), the polymerization inhibitor is at least one of hydroquinone, 2,5-di-tert-butyl hydroquinone, and p-hydroxyanisole.

Preferably, in step (3), the reactive diluent is at least one of propylene oxide butyl ether, propylene oxide phenyl ether, and ethylene glycol diglycidyl ether.

Preferably, the mass ratio of graphene-modified acrylate to epoxy resin is 0.25-0.35:1, the mass ratio of reactive diluent to epoxy resin is 0.8-1.0, and the mass ratio of catalyst to epoxy resin is 0.005-0.015 : 1, and the mass ratio of the polymerization inhibitor to the epoxy resin is 0.001-0.002: 1.

The epoxy resin is preferably epoxy resin E-44.

The invention also includes an application of the graphene graft-modified epoxy acrylate for preparing light-curing coatings.

In the present invention, also includes a kind of described light-curing coating added with the described graphene graft-modified epoxy acrylate, including the following components by weight:

In the present invention, in the photocurable coating (also referred to as UV light curing epoxy acrylate coating), preferably, the photoinitiator is isopropylthioxanthraquinone, diphenylphosphine oxide, hydroxyl At least one of cyclohexyl phenone and 1-hydroxycyclohexyl phenone.

Preferably, the leveling agent is organosilicon polyether copolymer and/or polydimethylsiloxane.

Preferably, the defoamer is GPE type and/or higher alcohol.

The preparation method of the photocurable coating of the present invention is obtained by stirring and mixing the components evenly.

In the present invention, a preferred preparation method of UV light curing epoxy acrylate coating comprises the following steps:

Step (A): add powdered graphite oxide and thionyl chloride (SOCl ₂ ) into the three-necked flask, and place the system in an oil bath at 60-70°C for condensation and reflux reaction for 19-24 hours; The thionyl chloride is distilled under reduced pressure at 40-50℃ until there is only a small amount remaining (can not be evaporated to dryness, preventing the aggregation of the acid chloride product and affecting the dispersion), the product is filtered and washed with a vacuum pump; the acid chloride product is washed with chloroform , and use chloroform to disperse the product, adjust the graphene concentration of acid chloride to be 0.5-1mg/ml, and ultrasonically disperse the product for 1-3h after the acid chloride reaction;

Step (B): Acyl Chloride Graphene Oxide:

Acyl chloride graphene pre-grafted hydroxyethyl methacrylate:

Add 80-100ml of chloroform solution containing graphene acyl chloride dropwise to 10-20ml of pyridine and 30-40ml of hydroxyethyl methacrylate mixed solution under stirring conditions at low temperature (0-2°C), then raise to room temperature , continue to stir for 1-3h. Use distilled water to wash the product, and finally freeze-dry to obtain a graphene acyl chloride grafted hydroxyethyl methacrylate sample;

Step (C): Preparation of Modified Epoxy Acrylate

The epoxy resin is added to the reactive diluent, and the reaction is stirred for 40-50 min. Then, the graphene-modified hydroxyethyl methacrylate, a catalyst and a polymerization inhibitor are slowly added to the above-mentioned reactive diluent, and the temperature is raised to react, and the reaction is maintained. The temperature is 115°C-135°C, keeping the acid value of the system less than 4.5-5 mg KOH/g, and finally cooling to room temperature to prepare the graphene-modified epoxy acrylate.

Wherein, the mass ratio of modified graphene grafted hydroxyethyl methacrylate to epoxy resin is 0.25-0.35:1, the mass ratio of reactive diluent to epoxy resin is 0.8-1.0, and the mass ratio of catalyst to epoxy resin is 0.8-1.0. The ratio is 0.005-0.015:1, and the mass ratio of polymerization inhibitor and epoxy resin is 0.001-0.002:1;

Step (D): Preparation of UV Light Curing Epoxy Acrylate Coating

70-90 parts by weight of modified epoxy acrylate, 1-7 parts by weight of photoinitiator, 0.04-0.4 part by weight of leveling agent, 0.02-0.12 part by weight of defoamer are stirred and dispersed under a stirrer for 3-6 hours. Obtained UV light curing epoxy acrylate coating.

The preferred preparation method of the UV light curing epoxy acrylate coating of the present invention, firstly uses thionyl chloride (SOCl ₂ ) to chlorinate graphene oxide, and then utilizes alkali to catalyze the reaction of graphene acyl chloride and hydroxyethyl methacrylate , to obtain graphene (graphene-modified hydroxyethyl methacrylate) with the introduction of polymerizable double bonds. Then the graphene-modified hydroxyethyl methacrylate and epoxy resin are copolymerized in a reactive diluent to obtain the graphene-grafted epoxy acrylate.

beneficial effect

In the present invention, graphene oxide and acrylate are bonded in-situ by means of an acylating agent (such as thionyl chloride), and then copolymerized with epoxy resin, so that graphene oxide is bonded in-situ into the polymer, which has good performance. The dispersing and emulsification effect, and the incomparable dispersion stability of physical blending, can significantly improve the properties of the coating added with the graphene modified polymer, and obtain epoxy acrylate light curing with high adhesion. The mechanical properties of the coating are greatly improved in adhesion and abrasion resistance, and the impact resistance, that is, the toughness, is significantly improved.

Detailed ways:

Example 1:

Step (1): Synthesize graphite oxide with modified Hummers method:

The preparation of graphene oxide by Hummers method is divided into three steps, namely low temperature reaction stage (0-5°C), medium temperature reaction stage (35-40°C) and high temperature reaction stage (90-95°C). After the reaction is completed, washing and post-treatment are required to obtain the desired product.

Low-temperature reaction stage: 10g of natural flake graphite (particle size 0.1um) and 5g of sodium nitrate NaNO _were added to a 500ml three-necked flask placed in an ice bath environment, and 404.8g of concentrated sulfuric acid (95%-98%) was added during slow stirring, After keeping for 30-40min, add 30g potassium permanganate KMnO ₄ in batches, and continue to keep in ice bath for 2h after adding for about ten minutes;

Medium temperature reaction stage: transfer the system to a constant temperature water bath device at 30-35°C, and keep the temperature for 3-6h. 460 g of deionized water was slowly added dropwise to the reaction system using a constant pressure funnel.

High temperature reaction stage: rapidly increase the temperature of the water bath to 95°C and keep it for 1h. After that, 480 g of deionized water was added dropwise with a constant pressure funnel and the stirring speed was continued to increase, and then 240 g of deionized water was added dropwise after stirring for 10 min. After the dropwise addition was completed, 88.8 g of hydrogen peroxide (30%) was slowly added.

Washing and post-treatment: after the reaction, directly use filter paper to filter while hot, and transfer the brown-yellow filter cake to a beaker after suction filtration. Then 235.8g of concentrated hydrochloric acid and 800g of deionized water mixture were added to the beaker, and suction filtration was continued. The product on the filter cake was transferred to a 500 ml beaker. The product in the beaker was washed with a low-speed centrifuge at 5000 r/min, 15 min/time, until the pH value of the upper layer of the test centrifuge tube no longer decreased. Transfer the bottom layer of the centrifuge tube to a watch glass and dry it in a vacuum oven at 50-60°C until it is completely dry. The dried graphene oxide is ground into powder.

Step (2): oxychloride graphene oxide:

350 g of powdered graphene oxide and 65.5 g of thionyl chloride (SOCl ₂ ) were added to the three-necked flask, and the system was placed in an oil bath at 60-70° C. for condensation and reflux reaction for 19-24 hours. Then, the remaining thionyl chloride in the system was distilled under reduced pressure at 50°C until only a small amount remained (can not be evaporated to dryness, preventing the aggregation of the acyl chloride product and affecting the dispersion), and the product was filtered and washed with a vacuum pump. The product of acyl chloride is washed with chloroform, and the product is dispersed with chloroform, and the graphene concentration of the acyl chloride is adjusted to be 0.5 mg/ml, and the product is ultrasonically dispersed for 1-3 hours after the acyl chlorination reaction.

Step (3): Graphene acyl chloride pre-grafted hydroxyethyl methacrylate:

85ml of chloroform solution containing graphene chloride was added dropwise to the mixed solution of 19.6g of pyridine and 37.5g of hydroxyethyl methacrylate under stirring at a low temperature (0-2°C), then raised to room temperature and continued to stir for 3h . The product was washed with distilled water, and finally freeze-dried to obtain a sample of graphene acyl chloride grafted with hydroxyethyl methacrylate.

Step (4): Preparation of Modified Epoxy Acrylate

30g epoxy resin (E-44) (average molecular weight is 454.5) is joined in 27g reactive diluent (ethylene glycol diglycidyl ether), stirring reaction 40-50min, then slowly adding step ( 3) the obtained graphene modified hydroxyethyl methacrylate 8.6g, catalyst 0.15g (tetraethylammonium bromide) and inhibitor 0.03g (p-hydroxyanisole), heat up and react, keep the reaction The temperature is 115°C-135°C, keeping the acid value of the system less than 4.5-5 mg KOH/g, and finally cooling to room temperature to prepare the graphene-modified epoxy acrylate.

Step (5): UV light curing epoxy acrylate coating preparation

35 g of modified epoxy acrylate, 2 g of photoinitiator (hydroxycyclohexyl phenone), 0.1 g of leveling agent (polydimethylsiloxane), and 0.02 g of defoamer (Defoamer CN-117) were mixed under stirring. The UV light-cured epoxy acrylate coating was prepared by stirring and dispersing for 3-6 h under the device.

Example 2:

Step (1): Synthesize graphite oxide with improved Hummers method: see step (1) in Example 1;

Step (2): oxychloride graphene oxide:

350g of powdered graphene oxide and 65.5g of thionyl chloride (SOCl2) were added to the three-necked flask, and the system was placed in an oil bath at 60-70°C for condensation and reflux reaction for 19-24 hours. Then, the remaining thionyl chloride in the system was distilled under reduced pressure at 50°C until only a small amount remained (can not be evaporated to dryness, preventing the aggregation of the acyl chloride product and affecting the dispersion), and the product was filtered and washed with a vacuum pump. The product of acyl chloride is washed with chloroform, and the product is dispersed with chloroform, and the graphene concentration of the acyl chloride is adjusted to be 0.5 mg/ml, and the product is ultrasonically dispersed for 1-3 hours after the acyl chlorination reaction.

Step (3): Graphene acyl chloride pre-grafted hydroxyethyl methacrylate:

90ml of chloroform solution containing graphene chloride was added dropwise to the mixed solution of 19.6g of pyridine and 37.5g of hydroxyethyl methacrylate under stirring at a low temperature (0-2°C), then raised to room temperature and continued to stir for 3h . The product was washed with distilled water, and finally freeze-dried to obtain a sample of graphene acyl chloride grafted with hydroxyethyl methacrylate.

Step (4): Preparation of Modified Epoxy Acrylate

30g epoxy resin (E-44) (average molecular weight is 454.5) is joined in 27g reactive diluent (ethylene glycol diglycidyl ether), stirring reaction 40-50min, then slowly adding step ( 3) the obtained graphene modified hydroxyethyl methacrylate 8.6g, catalyst 0.15g (tetraethylammonium bromide) and inhibitor 0.03g (p-hydroxyanisole), heat up and react, keep the reaction The temperature is 115°C-135°C, keeping the acid value of the system less than 4.5-5 mg KOH/g, and finally cooling to room temperature to prepare the graphene-modified epoxy acrylate.

Step (5): UV light curing epoxy acrylate coating preparation

35 g of modified epoxy acrylate, 2 g of photoinitiator (hydroxycyclohexyl phenone), 0.1 g of leveling agent (polydimethylsiloxane), and 0.02 g of defoamer (Defoamer CN-117) were mixed under stirring. The UV light-cured epoxy acrylate coating was prepared by stirring and dispersing for 3-6 h under the device.

Example 3:

Step (1): Synthesize graphite oxide with improved Hummers method: see step (1) in Example 1;

Step (2): oxychloride graphene oxide:

350g of powdered graphene oxide and 65.5g of thionyl chloride (SOCl2) were added to the three-necked flask, and the system was placed in an oil bath at 60-70°C for condensation and reflux reaction for 19-24 hours. Afterwards, the remaining thionyl chloride in the system was distilled under reduced pressure at 50°C until only a small amount remained (can not be evaporated to dryness, preventing the aggregation of the acyl chloride product and affecting the dispersion), and the product was filtered and washed with a vacuum pump. The product of acyl chloride is washed with chloroform, and the product is dispersed with chloroform, the graphene concentration of acyl chloride is adjusted to 0.5 mg/ml, and the product is ultrasonically dispersed for 1-3 hours after the acyl chlorination reaction.

Step (3): Graphene acyl chloride pre-grafted hydroxyethyl methacrylate:

90ml of chloroform solution containing graphene chloride was added dropwise to the mixed solution of 19.6g of pyridine and 37.5g of hydroxyethyl methacrylate under stirring at a low temperature (0-2°C), then raised to room temperature and continued to stir for 3h . The product was washed with distilled water, and finally freeze-dried to obtain a sample of graphene acyl chloride grafted with hydroxyethyl methacrylate.

Step (4): Preparation of Modified Epoxy Acrylate

30g epoxy resin (E-44) (average molecular weight is 454.5) is joined in 27g reactive diluent (ethylene glycol diglycidyl ether), stirring reaction 40-50min, then slowly adding step ( 3) obtained Graphene-modified hydroxyethyl methacrylate 9g, catalyst 0.15g (tetraethylammonium bromide) and polymerization inhibitor 0.03g (p-hydroxyanisole), heat up and react, keep the reaction temperature 115°C-135°C, keeping the acid value of the system less than 4.5-5 mg KOH/g, and finally cooling to room temperature to prepare the graphene-modified epoxy acrylate.

Step (5): UV light curing epoxy acrylate coating preparation

35 g of modified epoxy acrylate, 2 g of photoinitiator (hydroxycyclohexyl phenone), 0.1 g of leveling agent (polydimethylsiloxane), and 0.02 g of defoamer (Defoamer CN-117) were mixed under stirring. The UV light-cured epoxy acrylate coating was prepared by stirring and dispersing for 3-6 h under the device.

Example 4:

Step (1): Synthesize graphite oxide with improved Hummers method: see step (1) in Example 1;

Step (2): oxychloride graphene oxide:

350g of powdered graphene oxide and 65.5g of thionyl chloride (SOCl2) were added to the three-necked flask, and the system was placed in an oil bath at 60-70°C for condensation and reflux reaction for 19-24 hours. Then, the remaining thionyl chloride in the system was distilled under reduced pressure at 50°C until only a small amount remained (can not be evaporated to dryness, preventing the aggregation of the acyl chloride product and affecting the dispersion), and the product was filtered and washed with a vacuum pump. The product of acyl chloride is washed with chloroform, and the product is dispersed with chloroform, and the graphene concentration of the acyl chloride is adjusted to be 0.5 mg/ml, and the product is ultrasonically dispersed for 1-3 hours after the acyl chlorination reaction.

Step (3): Graphene acyl chloride pre-grafted hydroxyethyl methacrylate:

90ml of chloroform solution containing graphene chloride was added dropwise to the mixed solution of 19.6g of pyridine and 37.5g of hydroxyethyl methacrylate under stirring at a low temperature (0-2°C), then raised to room temperature and continued to stir for 3h . The product was washed with distilled water, and finally freeze-dried to obtain a sample of graphene acyl chloride grafted with hydroxyethyl methacrylate.

Step (4): Preparation of Modified Epoxy Acrylate

30g epoxy resin (E-44) (average molecular weight is 454.5) is joined in 27g reactive diluent (ethylene glycol diglycidyl ether), stirring reaction 40-50min, then slowly adding step ( 3) 9.3g of obtained graphene-modified hydroxyethyl methacrylate, 0.15g of catalyst (tetraethylammonium bromide) and 0.03g of inhibitor (p-hydroxyanisole), the temperature rises and reacts, keeping the reaction The temperature is 115°C-135°C, keeping the acid value of the system less than 4.5-5 mg KOH/g, and finally cooling to room temperature to prepare the graphene-modified epoxy acrylate.

Step (5): UV light curing epoxy acrylate coating preparation

35 g of modified epoxy acrylate, 2 g of photoinitiator (hydroxycyclohexyl phenone), 0.1 g of leveling agent (polydimethylsiloxane), and 0.02 g of defoamer (Defoamer CN-117) were mixed under stirring. The UV light-cured epoxy acrylate coating was prepared by stirring and dispersing for 3-6 h under the device.

Comparative Example 1:

Compared with Example 1, the difference is that the modified epoxy acrylate is replaced by ordinary epoxy resin.

Step (1): Preparation of epoxy acrylate

30g epoxy resin (E-44) (average molecular weight is 454.5) was added in 27g reactive diluent (ethylene glycol diglycidyl ether), stirred for 40-50min, then slowly added methyl in the above reactive diluent 9.3g of hydroxyethyl acrylate, 0.15g of catalyst (tetraethylammonium bromide) and 0.03g of inhibitor (p-hydroxyanisole), the temperature is raised to react, the reaction temperature is kept at 115℃-135℃, and the acid value of the system is kept less than 4.5-5mgKOH/g, and finally cooled to room temperature to obtain epoxy acrylate.

Step (2): UV light curing epoxy acrylate coating preparation

35g of epoxy acrylate, 2g of photoinitiator (hydroxycyclohexyl phenone), 0.1g of leveling agent (polydimethylsiloxane), and 0.02g of defoamer (Defoamer CN-117) were added under a stirrer. Stir and disperse for 3-6h to obtain UV light curing epoxy acrylate coating.

The beneficial effects of the present invention are further described below by experimental data:

Based on GB/T1732-1993 "Measurement Method of Impact Resistance of Paint Film", the weight of the weight is 1Kg, expressed as the maximum height that does not cause damage to the paint film, the unit is Kg·cm, to measure the flexibility of the paint film

Wear resistance is implemented according to GB/T1768-79(89)

The adhesion is performed according to GB/T9286-88, and the first grade is qualified

The detection data of each embodiment and comparative example are shown in Table 1:

Table 1

As can be seen from Table 1, after adding pre-grafted graphene, the mechanical properties of adhesion and abrasion resistance are greatly improved, and the most important thing is that its impact resistance, that is, toughness, is significantly improved.

Claims (7)

1. a kind of preparation method of the epoxy acrylate of graphene graft modification, which comprises the following steps:

Step (1): acylated graphene oxide is made in graphene oxide and acylation reaction；The acylating agent is thionyl chloride；

Step (2): acylated graphene oxide, the acrylate containing active group, acid binding agent are reacted, and graphene modified third is made Olefin(e) acid ester；

Step (3): epoxy resin is dissolved in reactive diluent, then adds graphene modified propylene made from step (2) Acid esters, catalyst and polymerization inhibitor are simultaneously copolymerized the epoxy acrylate that the graphene graft modification is made at 115 DEG C -135 DEG C； The acid value of polymerization process control system is less than 4.5-5mg KOH/g；

The mass ratio of graphene modification acrylate and epoxy resin is 0.25-0.35:1, reactive diluent and epoxy resin Mass ratio is 0.8-1.0, and the mass ratio of catalyst and epoxy resin is 0.005-0.015:1, the matter of polymerization inhibitor and epoxy resin Amount is than being 0.001-0.002:1；

The catalyst is N, at least one of N- dimethyl benzylamine, triphenylphosphine, tetraethylammonium bromide；

The polymerization inhibitor is at least one of hydroquinone, 2,5 di tert butyl hydroquinone, p-hydroxyanisole；

The reactive diluent be epoxy propane butyl ether, propylene oxide phenyl ether, in ethylene glycol diglycidylether extremely Few one kind；

The epoxy resin is epoxy resin E-44.

2. the preparation method of the epoxy acrylate of graphene graft modification as described in claim 1, which is characterized in that step (1) in, reaction temperature is 60-70 DEG C, reaction time 19-24h.

3. the preparation method of the epoxy acrylate of graphene graft modification as described in claim 1, which is characterized in that step (2) in, the acid binding agent is pyridine and/or triethylamine.

4. the preparation method of the epoxy acrylate of graphene graft modification as claimed in any one of claims 1 to 3, feature It is, the acrylate containing active group is the compound with 1 structure of formula:

In formula 1, Y is the alkyl of C1~5；R is H or methyl.

5. the preparation method of the epoxy acrylate of graphene graft modification as claimed in claim 4, which is characterized in that described The acrylate containing active group be (methyl) hydroxy-ethyl acrylate, (methyl) hydroxypropyl acrylate, (methyl) acrylic acid hydroxyl At least one of N-butyl.

6. the application of the epoxy acrylate of graphene graft modification made from a kind of method of any one of Claims 1 to 5, It is characterized in that, is used to prepare photocureable coating.

7. a kind of photocureable coating, which is characterized in that comprise the following components in parts by weight: