阅读说明：本技术 甲醚化氨基树脂的环保生产方法 (Environment-friendly production method of methylated amino resin ) 是由 李平 王文武 钟力 唐学军 况晓东 于 2020-06-09 设计创作，主要内容包括：甲醚化氨基树脂的环保生产方法,包括：将甲醇和强酸型阳离子树脂按比例加入反应釜；预热后再将多羟甲基三聚氰胺按比例加入反应釜；在反应釜内进行一次醚化反应；反应结束后,将阳离子树脂留置在反应釜内,并将一次反应溶液转移至后处理釜；在后处理釜中将反应溶液脱除水和过量的甲醇,得到一次产物；将一次产物重新转移至反应釜,并补加甲醇后进行二次醚化反应；反应结束后,仍将阳离子树脂留置在反应釜内,并将反应溶液移至后处理釜；在后处理釜中将反应溶液脱除水和过量的甲醇,从而得到二次产物。本发明的生产方法由于彻底解决了固体废盐的问题,从而使生产工艺更加绿色环保；同时也提高了产品品质,降低了生产成本。(The environment-friendly production method of the methylated amino resin comprises the following steps: adding methanol and strong acid type cation resin into a reaction kettle in proportion; after preheating, adding the polymethylol melamine into the reaction kettle in proportion; carrying out primary etherification reaction in a reaction kettle; after the reaction is finished, the cationic resin is left in the reaction kettle, and the primary reaction solution is transferred to a post-treatment kettle; removing water and excessive methanol from the reaction solution in a post-treatment kettle to obtain a primary product; transferring the primary product to the reaction kettle again, and performing secondary etherification reaction after methanol is supplemented; after the reaction is finished, the cationic resin is still remained in the reaction kettle, and the reaction solution is moved to a post-treatment kettle; the reaction solution was freed of water and excess methanol in the work-up pot to give a secondary product. The production method of the invention thoroughly solves the problem of solid waste salt, thereby ensuring that the production process is more environment-friendly; meanwhile, the product quality is improved, and the production cost is reduced.)

1. A method for producing a methylated amino resin, comprising:

1) adding methanol and strong acid type cation resin into a reaction kettle in proportion;

2) after preheating, adding the polymethylol melamine into the reaction kettle in proportion;

3) carrying out primary etherification reaction in a reaction kettle;

4) after the primary etherification reaction is finished, the cationic resin is left in the reaction kettle, and a primary reaction solution containing a reaction product, water and excessive methanol is transferred to a post-treatment kettle;

5) removing water and excessive methanol from the primary reaction solution in a post-treatment kettle to obtain a primary amino resin product;

6) transferring the primary amino resin product to the reaction kettle again, and performing secondary etherification reaction after methanol is supplemented;

7) after the secondary etherification reaction is finished, the cationic resin is still kept in the reaction kettle, and a secondary reaction solution containing a reaction product, water and excessive methanol is transferred to a post-treatment kettle;

8) and (3) removing water and excessive methanol from the secondary reaction solution in the post-treatment kettle to obtain an amino resin secondary product.

2. The production method according to claim 1, further comprising:

9) and carrying out filter pressing on the obtained amino resin to obtain a final resin product.

3. The production process according to claim 1, wherein the strong acid type cationic resin is a reusable insoluble solid particle.

4. The production process according to claim 1, wherein a filter is provided at the bottom of the reaction vessel to ensure that steps 4) and 7) are smoothly carried out.

5. The production process according to claim 1, wherein the etherification reaction temperature in the steps 3) and 6) is 50 to 80 ℃.

6. The production process according to claim 5, wherein the etherification reaction in the steps 3) and 6) is carried out while a condensing reflux means is also carried out to return the methanol escaped to the reaction solution.

Technical Field

The invention relates to environment-friendly production of methylated amino resin.

Background

As a downstream product of melamine, amino resin, especially methylated amino resin is mainly used as a coating cross-linking agent, and matched with polyester resin, acrylic resin, epoxy resin and the like, so that a coating film has excellent gloss, color retention, hardness, chemical resistance, water resistance, weather resistance and the like, and can be widely applied to industrial coatings such as automobiles, rigid furniture, household appliances, metal precoating and the like.

The synthesis of etherified amino resins using melamine, such as hexamethylol melamine or trimethylol melamine, is known in the art and can be found in the applicant's prior patents or patent applications CN 103739563B, CN103739803B, CN103709111B, CN 105968283A, CN105968281A, CN105968282A and CN106008870A, the entire contents of which are also incorporated herein by reference.

At present, liquid acid such as hydrochloric acid or nitric acid is generally used as an acid catalyst in the production of such amino resins, and after the reaction is finished, alkaline solutions such as sodium hydroxide, sodium carbonate, sodium bicarbonate and the like are used for stopping the reaction, the pH value is adjusted to be alkaline, and then reduced pressure distillation dehydration and dealcoholization are performed. Thus, a large amount of sodium salt is precipitated in the system, and the sodium salt needs to be completely removed to obtain a clear and transparent amino resin product. If the sodium salt is not completely removed, the transparency of the amino resin product is affected, and the film coating effect is affected in the case of back-end application. The removed sodium salt is also accompanied by a certain amount of amino resin, which affects the yield. In addition, the treatment of the solid waste salt also brings great trouble to enterprises: the extraction recovery treatment cost is high, more waste water is generated, and the equipment investment is large; the landfill treatment can pollute soil and influence water quality, and is extremely unfavorable for environmental protection.

Disclosure of Invention

The invention aims to provide an environment-friendly and efficient production method of methylated amino resin.

The method for producing a methylated amino resin according to the present invention comprises:

1) adding methanol and strong acid type cation resin into a closed reaction kettle in proportion;

2) after preheating, adding the polymethylol melamine into the reaction kettle in proportion;

3) carrying out primary etherification reaction in a reaction kettle;

4) after the primary etherification reaction is finished, the cationic resin is left in the reaction kettle, and a primary reaction solution containing a reaction product, water and excessive methanol is transferred to a post-treatment kettle;

5) removing water and excessive methanol from the primary reaction solution in a post-treatment kettle to obtain a primary amino resin product;

6) transferring the primary amino resin product to the reaction kettle again, and performing secondary etherification reaction after methanol is supplemented;

7) after the secondary etherification reaction is finished, the cationic resin is still kept in the reaction kettle, and a secondary reaction solution containing a reaction product, water and excessive methanol is transferred to a post-treatment kettle;

8) and (3) removing water and excessive methanol from the secondary reaction solution in the post-treatment kettle to obtain an amino resin secondary product.

The production method according to the present invention may further include:

9) and carrying out filter pressing on the obtained secondary product of the amino resin, thereby obtaining a final resin product.

During filter pressing, a certain amount of diatomite can be added into the post-treatment kettle to reduce the impurity content to the maximum extent.

According to the production method of the present invention, the strong acid type cationic resin is preferably reusable insoluble solid particles (spherical porous particles) whose main active group is a sulfonic acid group, for example. Such strongly acidic cationic resins are commercially available.

According to the invention, the bottom of the reaction vessel is preferably provided with a corresponding filter to retain the cationic resin in the reaction vessel and to allow the reaction solution to flow out of the reaction vessel by gravity or suction.

According to the production method, the etherification reaction temperature is preferably 50-80 ℃. The etherification reaction time is preferably 60 to 240 min.

In the present invention, the polymethylol melamine may be trimethylol, tetrahydroxy, pentahydroxy and hexamethylol melamine, and preferably hexamethylol melamine. During etherification, the polymethylol melamine and the methanol are fed according to the molar ratio of 1: 10-30, the amount of the strong acid type cationic resin is 5-50% (weight ratio) of the total fed amount, and the pH value is ensured to be in a proper acidity range, such as 3-5.

The production process according to the present invention, wherein the etherification reaction is carried out while a condensing reflux means is preferably carried out so that the methanol escaped is returned to the reaction solution. The condensation reflux measures ensure the stability of the mixture ratio of the reaction materials.

The production method according to the present invention, wherein the preheating temperature range in the step 2) is preferably around 40 ℃. The preheating means ensures the catalytic efficiency of the strong acid type cation resin. During the secondary etherification, a preheating process is not needed.

According to the production method, as the secondary etherification reaction is adopted, water generated in the raw materials and in the reaction process is eliminated to the maximum extent, so that the polymerization degree of the product is effectively ensured.

According to the production method of the invention, the reaction can be terminated simply by separating the strong acid type cation resin from the reaction solution without adding extra alkali liquor to terminate the reaction. Therefore, no waste salt is generated in the whole production process, so that the production process is more stable, and the color and turbidity of the resin product are better. This overrides the inherent cognitive combination of liquid acid + base solution used in the conventional process and also eliminates the need to monitor the pH after the reaction.

The production method of the invention thoroughly solves the problem of solid waste salt, thereby ensuring that the production process is more environment-friendly; meanwhile, the product quality is improved, the production cost is reduced, and the investment of waste salt treatment equipment is saved.

According to an alternative embodiment of the present invention, butanol may also be used instead of methanol to carry out the corresponding etherification reaction to obtain the corresponding butylated amino resin.

Detailed Description

The present invention is further described below in conjunction with specific examples, but it will be understood by those skilled in the art that the examples described below are for purposes of better understanding and practice onlyThe invention is not intended to be limited in any way. The volume of the reaction kettle is 8m³And a filter is arranged at the liquid outlet at the bottom.