CN101914171A - A kind of sulfonic acid type UV curing aqueous epoxy emulsion and preparation method thereof - Google Patents

Abstract

The invention discloses a sulfonic acid type UV curable water-based epoxy emulsion and a synthesis method thereof. In the method, an epoxy resin and maleic anhydride are subjected to a ring-opening esterification reaction under the action of a catalyst, and the reaction is carried out at 90-120°C for 3 ~5h, when the acid value drops to 40-60% of the initial acid value, the reaction ends, and the epoxy maleate is obtained; then the epoxy maleate is heated to 50-90°C, and the acyl chloride agent trichloride is added dropwise Phosphate, react at 50-90°C for 2-3 hours to obtain epoxy fumaryl chloride; then adjust the pH value of sulfamic acid to 8-10 with NaOH alcohol solution, react with epoxy fumaric acid chloride, and add water to disperse UV curable aqueous epoxy resin emulsions are available. The product obtained by the invention has the advantages of good color, good storage stability, and excellent coating film performance, and the product can be applied to the field of water-based UV curing paint.

Description

A kind of sulfonic acid type UV curing aqueous epoxy emulsion and preparation method thereof

technical field

The invention relates to a water-based epoxy emulsion, in particular to a sulfonic acid type UV curing water-based epoxy emulsion and a synthesis method thereof.

Background technique

Photocuring is a rapidly developing "green" new technology. Since the 1970s, radiation curing technology has become more and more popular in developed countries, and has been widely used in various coatings, inks and adhesives. Among them, the development of UV curing (ultraviolet light curing) technology is more rapid. The development of light-curing materials in my country began in the early 1970s, and industrial production began in the 1990s. At present, it has become a major producer of light-curing raw materials and products after the United States and Japan. Although light-curing technology and materials have developed rapidly, there are still some problems that affect its application and promotion, especially the damage of reactive diluents and volatile organic compounds to the human body and the pollution of the environment. Water-based light-curing systems can overcome these disadvantages. Water-based light-curing coatings combine the characteristics of traditional UV-curing coatings and water-based coatings. Compared with traditional oil-based UV coatings, they have the following advantages: (1) Water is the most convenient and cheapest raw material, and it can be diluted with water instead of reactive diluents. Oligomers, it is easy to adjust the viscosity, and can realize non-reactive diluent formula; (2) No active diluent, no VOC, irritation and odor problems; (3) Applicable to various coating equipment, especially for Spraying is safe; (4) It can avoid the curing volume shrinkage caused by the use of reactive diluents; (5) It can realize thin coating coating and reduce costs; (6) The coating equipment and containers can be cleaned with water-based cleaning fluid. In addition, the contradiction between the hardness and flexibility of the coating film is solved.

Water-based oligomers are an important part of water-based UV-curable coatings, which determine the physical and mechanical properties of the cured film such as hardness, flexibility, strength and wear resistance, and affect the light-curing speed. From the structural point of view, water-based oligomers must have photopolymerizable groups, such as acryloxy, methacryloxy, vinyl, allyl, etc., because acryloxy has the fastest curing speed , so it is the main variety of various acrylic resins. Second, the molecular chain must contain a certain number of hydrophilic groups, such as carboxyl, hydroxyl, amino, quaternary ammonium, ether, amide, sulfonic acid, etc. The currently used water-based oligomers mainly include acrylates and unsaturated polyesters. , polyurethane acrylate and epoxy acrylate, etc. These water-based oligomers mainly use carboxylate as the hydrophilic group, and there are not many reports on sulfonic acid-type water-based oligomers.

At present, epoxy acrylate is the most used photocurable oligomer. Some studies use bisphenol A epoxy resin and acrylic acid ring-opening reaction to generate epoxy acrylate, and then use maleic anhydride esterification to introduce carboxyl groups. Alkaline neutralization and dispersion to obtain water-based UV-curable epoxy acrylic oligomer; acrylic acid and epoxy resin can also be used to react epoxy acrylate, and then ring-opening esterification with maleic anhydride to introduce carboxyl and unsaturated groups, adding Neutralized with alkali to form UV curable water-based water-based epoxy emulsion. These methods all take the carboxyl in the maleic anhydride as the hydrophilic group. Compared with the sulfonic acid group, the carboxyl group has weaker electronegativity, and the formed epoxy oligomer has poor hydrophilicity, and the storage stability in the later stage is also poor. poor.

Contents of the invention

The above technical problem to be solved by the present invention is to provide a sulfonic acid type UV curable water-based epoxy resin emulsion and a preparation method thereof. The product has the advantages of good color, good storage stability, and excellent coating performance.

In order to achieve the above object, the present invention adopts following technical scheme:

A preparation method for sulfonic acid type UV curing aqueous epoxy emulsion, comprising the following steps:

(1) Ring-opening esterification reaction of epoxy resin and maleic anhydride under the action of a catalyst, the molar ratio of epoxy resin and maleic anhydride is 1:2～2.1, react at 90～120°C for 3～ 5h, when the acid value drops to 40-60% of the initial acid value, the reaction ends, and the reaction obtains epoxy maleate;

(2) Heat the epoxy maleate to 50-90°C, add the acid chloride agent phosphorus trichloride dropwise, the molar ratio of the epoxy maleate to phosphorus trichloride is 1:0.5-2, at 50 React at ~90°C for 2 to 3 hours to obtain epoxy fumaryl chloride;

(3) Adjust the pH value of sulfamic acid to 8-10 with NaOH alcohol solution, and then react with epoxy fumaric acid chloride at 50-80°C for 1-3h, the molar ratio of epoxy fumaric acid chloride to aminosulfonic acid The ratio is 1:2~2.1, adding water to disperse can obtain UV curable water-based epoxy resin emulsion.

In the step (1), the epoxy resin is bisphenol A epoxy resin E51 or E44.

In the step (3), the aminosulfonic acid is p-aminobenzenesulfonic acid, N-methyl taurine or taurine.

The mass concentration of the NaOH alcohol solution is preferably 5%-10%.

In the described step (1), the acid value is measured as follows:

Take a sample (0.5 ~ 1g) and place it in a 100mL Erlenmeyer flask, add 25ml of a mixed solution of ethanol and acetone with a volume ratio of 1:1 to completely dissolve the sample, add 0.1ml of phenolphthalein indicator dropwise, and titrate to pink with KOH-ethanol standard solution until color, count;

Do a blank test, blank test method: take 25ml of a mixed solution of ethanol and acetone with a volume ratio of 1:1, add 0.1ml of phenolphthalein indicator dropwise, titrate with KOH-ethanol standard solution until pink, and count;

Acid value=56.1×[(VV ₀ )c/m]

In the formula: V-the volume of KOH consumed by the titration sample, in ml;

V ₀ - the volume of KOH consumed for titrating the blank, in ml; m - the mass of the sample, in g;

The molar concentration of c-KOH titrant, in mol/mL.

A sulfonic acid type UV curable water-based epoxy emulsion is prepared by the above method.

The preparation method of a kind of sulfonic acid type UV curing aqueous epoxy emulsion of the present invention can be realized by following specific steps:

(1) Epoxy resin and maleic anhydride ring-opening esterification reaction, reaction obtains epoxy maleate.

(2) Heat the above-mentioned epoxy maleic acid ester to 50-90°C, add the acid chloride agent phosphorus trichloride dropwise, and the epoxy fumaryl chloride should be obtained.

(3) Adjust the pH value of sulfamic acid to 8-10 with NaOH alcohol solution, and then react with epoxy fumaryl chloride at 50-80°C.

(4) cool down, add water to disperse and obtain UV curable water-based epoxy emulsion.

The invention uses epoxy resin, maleic anhydride and p-aminobenzenesulfonic acid as initial raw materials, undergoes ring-opening esterification, acyl chloride and condensation, and adds water to disperse to obtain the final product.

Compared with the prior art, the beneficial effects of the present invention are as follows:

(1) Firstly, the molecular reactivity can be improved by acyl chloride, and sulfamic acid can be easily introduced.

(2) The synthetic route is simple, the side reaction is less, no pollution, and the product with good application performance can be obtained without purification in the reaction process.

(3) The present invention makes the epoxy resin hydrophilic by introducing sulfonic acid groups, and introduces acryloyloxy groups by reacting with maleic anhydride to carry out photopolymerization.

(4) Compared with carboxylic acid type, sulfonic acid type UV curing water-based epoxy emulsion has better color and better storage stability.

(5) There are electron-withdrawing groups-carbonyl groups on both sides of the double bond in the prepared UV-curable epoxy resin, which makes the double bond more active and easier to participate in the reaction and photocuring occurs.

Detailed ways

The present invention will be further described below in conjunction with the examples, but the protection scope of the present invention is not limited to the scope expressed in the examples.

Example 1

(1) Mix epoxy resin E51 and maleic anhydride at a molar ratio of 1:2, the initial acid value is 190.6 mg/g resin, react at 90°C for 1 hour, then heat up to 120°C, and continue the reaction. When the acid value dropped to 96mg/g resin, the reaction was stopped to obtain epoxy maleic acid ester. The acid value is determined by the following method:

Take a sample (0.5 ~ 1g) and place it in a 100mL Erlenmeyer flask, add 25ml of a mixed solution of ethanol and acetone with a volume ratio of 1:1 to dissolve the sample completely, add dropwise 0.1ml of phenolphthalein indicator, and titrate with KOH-ethanol standard solution Count until pink. At the same time do a blank test. Blank test method: Take 25ml of a mixed solution of ethanol and acetone with a volume ratio of 1:1, add dropwise 0.1ml of phenolphthalein indicator, titrate with KOH-ethanol standard solution until pink, and count.

Acid value=56.1×[(VV ₀ )c/m]

In the formula: V-KOH volume consumed by the titration sample, ml;

V ₀ - the volume of KOH consumed for titrating the blank, ml; m - the mass of the sample, g;

The molar concentration of c-KOH titrant, mol/mL.

(2) Epoxy maleic acid ester is heated to 50 ℃, drips acid chloride reagent phosphorus trichloride, and the mol ratio of epoxy maleic acid ester and phosphorus trichloride is 1: 1, after dropping, continue to React at 50°C for 2h to end the reaction. The product obtained is epoxy fumaryl chloride.

(3) At 60°C, the p-aminobenzenesulfonic acid was adjusted to a pH value of 8 with a NaOH alcohol solution with a mass concentration of 5%, and epoxy fumaryl chloride was added dropwise, and the addition was completed within 1 to 2 hours. The molar ratio of epoxy fumaryl chloride is 2:1. After the dropwise addition, the reaction is continued at 60° C. for 1 hour to obtain the target product, which is dispersed with water to obtain a UV-curable water-based epoxy emulsion.

Example 2

(1) Mix epoxy resin E51 and maleic anhydride at a molar ratio of 1:2.1. The initial acid value is 178.4 mg/g resin. After reacting at 100°C for 1 hour, the temperature is raised to 120°C to continue the reaction. When the acid value dropped to 89mg/g resin, the reaction was stopped to obtain epoxy maleic acid ester. The measuring method of acid value is with embodiment 1.

(2) Epoxy maleic acid ester is heated to 90 ℃, and acid chloride reagent phosphorus trichloride is added dropwise, and the molar ratio of epoxy maleic acid ester and phosphorus trichloride is 1: 0.5, continue in React at 90°C for 2h to end the reaction. The product obtained is epoxy fumaryl chloride.

(3) Cooling down to 80°C, adjusting the pH value to 9 with a 10% NaOH alcohol solution with a mass concentration of p-aminobenzenesulfonic acid, adding epoxy fumaryl chloride dropwise, and finishing dropping in 1 to 2 hours, the sulfanilic acid and The molar ratio of epoxy fumaryl chloride is 2.1:1. After the dropwise addition, the reaction is continued at 80° C. for 1 hour to obtain the target product, which is dispersed with water to obtain a UV-curable water-based epoxy emulsion.

Example 3

(1) Mix epoxy resin E44 and maleic anhydride at a molar ratio of 1:2, the initial acid value is 172.4 mg/g resin, react at 100°C for 1 hour, then heat up to 120°C, and continue the reaction. When the acid value dropped to 87 mg/g resin, the reaction was stopped to obtain epoxy maleic acid ester. The measuring method of acid value is with embodiment 1.

(2) Epoxy maleic acid ester is heated to 70 ℃, and acid chloride reagent phosphorus trichloride is added dropwise, and the molar ratio of epoxy maleic acid ester and phosphorus trichloride is 1: 2, after dropping, continue to React at 70°C for 2h to end the reaction. The product obtained is epoxy fumaryl chloride.

(3) At 80°C, adjust the pH value of taurine to 10 with a 5% NaOH alcohol solution with a mass concentration of 5%, and then add epoxy fumaryl chloride dropwise. The molar ratio of the acid chloride was 2:1. After the dropwise addition, the reaction was continued at 80° C. for 1 h to obtain the target product, which was dispersed with water to obtain a UV-curable water-based epoxy emulsion.

Example 4

(1) Mix epoxy resin E44 and maleic anhydride at a molar ratio of 1:2.1. The initial acid value is 178.4 mg/g resin. After reacting at 100°C for 1 hour, the temperature is raised to 120°C to continue the reaction. When the acid value dropped to 89mg/g resin, the reaction was stopped to obtain epoxy maleic acid ester. The measuring method of acid value is with embodiment 1.

(2) Epoxy maleic acid ester is heated to 70 ℃, and acid chloride reagent phosphorus trichloride is added dropwise, and the molar ratio of epoxy maleic acid ester and phosphorus trichloride is 1: 1, after dropping, continue to React at 70°C for 2h to end the reaction. The product obtained is epoxy fumaryl chloride.

(3) At 70°C, adjust the pH value of N-methyl taurine to 9 with a mass concentration of 10% NaOH alcohol solution, and then add epoxy fumaryl chloride dropwise. After 1-2 hours, the N-methyl taurine The molar ratio of taurine to epoxy fumaryl chloride is 2:1. After the dropwise addition, the reaction is continued at 70° C. for 1 hour to obtain the target product, which is then dispersed with water to obtain a UV-curable water-based epoxy emulsion.

In the prior art, there is an esterification reaction of epoxy resin and maleic anhydride under the effect of a tertiary amine catalyst to synthesize UV-curable water-based epoxy resin with unsaturated groups and hydrophilic groups, and its oligomers The structural formula of the components is:

Its specific preparation process is: add 45.45 g of E-44 resin in a four-necked flask equipped with a thermometer, a condenser, and a dropping funnel, use 5 g of acetone as a diluent, stir to completely dissolve the epoxy resin, and then add 19.6 g of cis Butenedioic anhydride and 0.65g triphenylphosphine, the initial acid value was measured as 160mgKOH/g resin, the temperature was raised to 100°C, and the reaction was stopped when the acid value reached 80mgKOH/g resin at constant temperature. The temperature was lowered to 50° C., and 70 g of NaOH aqueous solution with a mass concentration of 6% was added for neutralization and dispersion to obtain the target product.

Take this as a comparison sample, and compare it with the performance index of the emulsion of each embodiment of the present invention as shown in Table 1. Compared with the present invention, the difference of the comparison sample is mainly the hydrophilic group, but there is a gap between the obtained emulsion and the coating film performance and the product obtained in the present invention, such as: emulsion appearance, coating appearance, storage stability, hardness, Adhesion, abrasion resistance and impact resistance, etc., especially in terms of storage stability, in Examples 1 to 4 of the present invention, there is no delamination phenomenon after storage for more than 6 months, while the storage time of the comparison product exceeds one month. Stratification occurs. The present invention has shown huge superiority especially.

Each embodiment of table 1 obtains emulsion performance

Claims (4)

1. a preparation method of sulfonic acid type UV curing aqueous epoxy emulsion is characterized in that comprising the following steps: (1) Ring-opening esterification reaction of epoxy resin and maleic anhydride under the action of a catalyst, the molar ratio of epoxy resin and maleic anhydride is 1:2～2.1, react at 90～120°C for 3～ 5h, when the acid value drops to 40-60% of the initial acid value, the reaction ends, and the reaction obtains epoxy maleate; (2) Heat the epoxy maleate to 50-90°C, add the acid chloride agent phosphorus trichloride dropwise, the molar ratio of the epoxy maleate to phosphorus trichloride is 1:0.5-2, at 50 React at ~90°C for 2 to 3 hours to obtain epoxy fumaryl chloride; (3) Adjust the pH value of sulfamic acid to 8-10 with NaOH alcohol solution, and then react with epoxy fumaric acid chloride at 50-80°C for 1-3h, the molar ratio of epoxy fumaric acid chloride to aminosulfonic acid The ratio is 1:2~2.1, adding water to disperse can obtain UV curable water-based epoxy resin emulsion. In the step (1), the epoxy resin is bisphenol A epoxy resin E51 or E44. In the step (3), the aminosulfonic acid is p-aminobenzenesulfonic acid, N-methyl taurine or taurine. 2. The preparation method of the sulfonic acid type UV curable water-based epoxy emulsion according to claim 1, characterized in that: the mass concentration of the NaOH alcohol solution is 5% to 10%. 3. the preparation method of sulfonic acid type UV curing aqueous epoxy emulsion according to claim 1 is characterized in that: in described step (1), acid value is measured by the following method: Take a sample (0.5 ~ 1g) and place it in a 100mL Erlenmeyer flask, add 25ml of a mixed solution of ethanol and acetone with a volume ratio of 1:1 to completely dissolve the sample, add 0.1ml of phenolphthalein indicator dropwise, and titrate with KOH-ethanol standard solution to Up to pink, count; Do a blank test, blank test method: take 25ml of a mixed solution of ethanol and acetone with a volume ratio of 1:1, add 0.1ml of phenolphthalein indicator dropwise, titrate with KOH-ethanol standard solution until pink, and count; Acid value=56.1×[(VV ₀ )c/m] In the formula: V-the volume of KOH consumed by the titration sample, in ml; V ₀ - the volume of KOH consumed for titrating the blank, in ml; m - the mass of the sample, in g; The molar concentration of c-KOH titrant, in mol/mL. 4. A sulfonic acid type UV curing aqueous epoxy emulsion is characterized in that it is prepared by the method according to claim 1.