阅读说明：本技术 一种阻燃尼龙树脂及其制备方法 (Flame-retardant nylon resin and preparation method thereof ) 是由 赵海鹏 陈贞 张延兵 代永豪 赵亚奇 胡顺朋 刘伟 张罡 董英英 李刚 夏学莲 于 2020-03-27 设计创作，主要内容包括：本发明涉及树脂领域,具体涉及一种阻燃尼龙树脂及其制备方法；一种阻燃尼龙树脂,由尼龙66盐、去离子水和阻燃盐聚合而成；阻燃盐是由阻燃剂2-(二甲基磷酸酯)-4,6(乳酸)-三嗪环与己二胺制备而成。本发明阻燃剂由三聚氯氰、亚磷酸三甲酯和乳酸合成,再与己二胺合成阻燃盐,最后阻燃盐、尼龙66盐和去离子水合成阻燃尼龙66；本发明所使用阻燃剂为三嗪环类二元酸,分子量很小,磷元素含量高；该阻燃剂含有三嗪环以及氮磷阻燃元素使其具有很好的阻燃效果；并且,该结构含有两个羧酸基团,活性高,能与有机官能团充分结合,能够很好的接入到尼龙的主链上,有利于提高产品的阻燃性能。(The invention relates to the field of resin, in particular to flame-retardant nylon resin and a preparation method thereof; a flame-retardant nylon resin is polymerized by nylon 66 salt, deionized water and flame-retardant salt; the flame-retardant salt is prepared from a flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring and hexamethylenediamine. The flame retardant is synthesized by cyanuric chloride, trimethyl phosphite and lactic acid, and then synthesized with hexamethylene diamine into flame retardant salt, and finally synthesized into flame retardant nylon 66 by the flame retardant salt, nylon 66 salt and deionized water; the flame retardant used in the invention is triazine ring binary acid, the molecular weight is very small, and the phosphorus content is high; the flame retardant contains triazine ring and nitrogen-phosphorus flame retardant elements, so that the flame retardant has a good flame retardant effect; in addition, the structure contains two carboxylic acid groups, has high activity, can be fully combined with organic functional groups, can be well grafted to the main chain of nylon, and is favorable for improving the flame retardant property of products.)

1. The flame-retardant nylon resin is characterized by being prepared by polymerizing nylon 66 salt, deionized water and flame-retardant salt; the flame retardant salt is prepared from a flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring and hexamethylenediamine, and the flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring has the structure:

2. the flame retardant nylon resin of claim 1, wherein the mass ratio of the nylon 66 salt, the deionized water and the flame retardant salt is 100: 100: (0.1-10).

3. A method for preparing a flame retardant nylon resin according to claim 1 or 2, comprising the steps of:

(1) the method comprises the following steps of: 1-2, synthesizing nylon 66 salt from hexamethylenediamine and adipic acid, and dissolving the nylon 66 salt with deionized water;

(2) pouring the dissolved nylon 66 salt and the flame-retardant salt into a high-pressure reaction kettle, introducing nitrogen to remove air in the reaction kettle, reacting for 3-5 hours under the conditions that the pressure is 1.3-2.0 MPa and the temperature is 170-230 ℃, then recovering to normal pressure, and reacting for 2-4 hours under the condition that the temperature is 240-270 ℃; and finally, naturally cooling and then pelletizing to obtain the flame-retardant nylon resin.

4. The preparation method of the flame-retardant nylon resin according to claim 3, wherein in the step (2), the flame-retardant nylon resin is milk white, the melting range is 250-270 ℃, the relative viscosity is 2.10-2.50, the flame-retardant level of the flame-retardant nylon resin is U L-94V-0 grade, the tensile strength is not lower than 80.0MPa, and the elongation at break is 64.5-66.5%.

5. The method of preparing flame retardant nylon resin of claim 4, wherein the step (2) of synthesizing the flame retardant salt comprises the steps of:

① adding cyanuric chloride into organic solvent S1, slowly adding trimethyl phosphite dropwise and starting reaction, and after the reaction is finished, starting distillation to obtain product P1;

②, dissolving the product P1 in step ① in an organic solvent S2, then dripping lactic acid and starting reaction, after the reaction is finished, filtering, washing the product with the organic solvent S3, and finally drying to obtain 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring;

③, reacting the 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring in the step ② with hexamethylenediamine in deionized water for 1-2 h to obtain a flame-retardant salt solution, and distilling and drying the flame-retardant salt solution to obtain the flame-retardant salt, wherein the molar ratio of the 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring to the hexamethylenediamine is 1: 1.02.

6. The method for preparing the flame retardant nylon resin according to claim 5, wherein in the step ①, the mass ratio of the cyanuric chloride to the organic solvent S1 is 1: 2-5, and the molar ratio of the cyanuric chloride to the trimethyl phosphite is 1: 1-1.5.

7. The method for preparing the flame-retardant nylon resin according to claim 6, wherein in the step ①, the organic solvent S1 is one or more selected from toluene, acetonitrile, acetone, benzene, dimethyl sulfoxide, dichloromethane and N, N-dimethyl sulfoxide, the reaction temperature is 6-14 ℃, and the reaction time is 1-5 hours.

8. The method for preparing flame retardant nylon resin of claim 7, wherein in the step ②, the molar ratio of the product P1 to lactic acid is 1: 1.8-2.4.

9. The method for preparing the flame-retardant nylon resin according to claim 8, wherein in the step ②, the organic solvent S2 and the organic solvent S3 are respectively one or more of toluene, acetonitrile, acetone, benzene, dimethyl sulfoxide, dichloromethane and N, N-dimethyl sulfoxide, the reaction temperature is 60-90 ℃, and the reaction time is 4-8 hours.

Technical Field

The invention relates to the field of resin, in particular to flame-retardant nylon resin and a preparation method thereof.

Background

In recent years, the economy of China is more and more developed, high-rise buildings are all over the visual field, and the decoration in the high-rise buildings is luxurious; when the interior decoration material has no flame retardant effect or the flame retardant effect is poor, once a high-rise building is in a fire, the potential hazard brought by the interior decoration material is difficult to estimate; therefore, adding a flame retardant to a material and providing the material with flame retardancy, difficult spreadability and smokeless properties is currently the more common approach.

According to the classification of flame-retardant materials, flame retardants are roughly classified into two types, one is additive flame retardants, and the other is reactive flame retardants; the additive flame retardants occupy the vast majority of the whole industry, and if the additive flame retardants are classified according to elements, the additive flame retardants are classified into halogen series, phosphorus series, nitrogen series, aluminum series, magnesium series and the like, and can also be classified into inorganic flame retardants and organic flame retardants in a general way; compared with organic flame retardants and inorganic flame retardants, the inorganic flame retardants have the advantages of high stability, low volatility, low smoke toxicity, low cost and the like, but have the disadvantages of large filling amount, small bonding force with polymers, poor compatibility, large influence on high polymer processing and mechanical properties and the like, so that the organic flame retardants are more worthy of exploration.

The invention patent CN104211954A relates to a preparation method of a halogen-free flame retardant nylon 66 polymer, firstly, reacting a reactive flame retardant DOPO derivative with dibasic acid or diamine to generate salt, and then carrying out polymerization reaction on the generated salt and nylon 66 salt to prepare the halogen-free flame retardant nylon polymer; the flame-retardant nylon has certain flame retardance, but the flame retardant has large molecular weight, small relative phosphorus content and poor flame-retardant effect, and if the nylon has better flame retardance, the addition amount of the flame retardant is increased, so that the cost is increased and the mechanical property of the nylon is reduced.

The patent with publication number CN266445A discloses a polymer-bonded non-halogen flame-retardant composition, which is characterized in that a reaction type flame retardant and a nylon monomer are copolymerized to obtain a flame-retardant nylon polymer, and the reaction type flame retardant is grafted into a nylon polymer molecular chain, so that the flame retardant property of the nylon polymer is improved and can be maintained for a long time; but the technical problem that the flame-retardant unit is degraded due to overhigh temperature in the polymerization and processing processes of nylon is not solved, and the flame-retardant performance and the mechanical property of the prepared flame-retardant nylon are also influenced.

Therefore, it is required to provide a flame retardant nylon material with good flame retardant effect and without affecting mechanical properties.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the flame-retardant nylon resin and the preparation method thereof, which not only can not generate negative influence on the mechanical property of nylon, but also can ensure that the nylon has good flame-retardant effect under the condition of adding few flame retardants.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

a flame-retardant nylon resin is polymerized by nylon 66 salt, deionized water and flame-retardant salt; the flame retardant salt is prepared from a flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring and hexamethylenediamine, and the flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring has the structure:

preferably, the mass ratio of the nylon 66 salt, the deionized water and the flame retardant salt is 100: 100: (0.1-10).

A preparation method of flame-retardant nylon resin comprises the following steps:

(1) the method comprises the following steps of: 1-2, synthesizing nylon 66 salt from hexamethylenediamine and adipic acid, and dissolving the nylon 66 salt with deionized water;

(2) pouring the dissolved nylon 66 salt and the flame-retardant salt into a high-pressure reaction kettle, introducing nitrogen to remove air in the reaction kettle, reacting for 3-5 hours under the conditions that the pressure is 1.3-2.0 MPa and the temperature is 170-230 ℃, then recovering to normal pressure, and reacting for 2-4 hours under the condition that the temperature is 240-270 ℃; and finally, naturally cooling and then pelletizing to obtain the flame-retardant nylon resin.

Preferably, in the step (2), the flame-retardant nylon resin is milk white, the melting range is 250-270 ℃, the relative viscosity is 2.10-2.50, the flame-retardant level of the flame-retardant nylon resin is U L-94V-0 grade, the tensile strength is not lower than 80.0MPa, and the elongation at break is 64.5-66.5%.

Preferably, in step (2), the synthesis of the flame retardant salt comprises the following steps:

① adding cyanuric chloride into organic solvent S1, slowly adding trimethyl phosphite dropwise and starting reaction, and after the reaction is finished, starting distillation to obtain product P1;

②, dissolving the product P1 in step ① in an organic solvent S2, then dripping lactic acid and starting reaction, after the reaction is finished, filtering, washing the product with the organic solvent S3, and finally drying to obtain 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring;

③, reacting the 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring in the step ② with hexamethylenediamine in deionized water for 1-2 h to obtain a flame-retardant salt solution, and distilling and drying the flame-retardant salt solution to obtain the flame-retardant salt, wherein the molar ratio of the 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring to the hexamethylenediamine is 1: 1.02.

Preferably, in the step ①, the mass ratio of the cyanuric chloride to the organic solvent S1 is 1: 2-5, and the molar ratio of the cyanuric chloride to the trimethyl phosphite is 1: 1-1.5.

Preferably, in the step ①, the organic solvent S1 is one or more of toluene, acetonitrile, acetone, benzene, dimethyl sulfoxide, dichloromethane and N, N-dimethyl sulfoxide, the reaction temperature is 6-14 ℃, and the reaction time is 1-5 hours.

Preferably, in the step ②, the molar ratio of the product P1 to the lactic acid is 1: 1.8-2.4.

Preferably, in the step ②, the organic solvent S2 and the organic solvent S3 are respectively one or more of toluene, acetonitrile, acetone, benzene, dimethyl sulfoxide, dichloromethane and N, N-dimethyl sulfoxide, the reaction temperature is 60 to 90 ℃, and the reaction time is 4 to 8 hours.

(III) advantageous effects

(1) The flame retardant salt is prepared from a flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring and hexamethylenediamine, wherein the flame retardant 2- (dimethyl phosphate) -4,6 (lactic acid) -triazine ring and hexamethylenediamine are synthesized from cyanuric chloride, trimethyl phosphite and lactic acid, and finally the flame retardant salt, nylon 66 salt and deionized water are polymerized into the flame retardant nylon resin in a high-pressure reaction kettle; the flame retardant used in the invention is triazine ring diacid, which is a new flame retardant structure, and the molecular weight of the flame retardant is very small from the structure, so that the content of nitrogen and phosphorus elements is improved; the flame retardant contains triazine ring and nitrogen and phosphorus flame retardant elements, so that the flame retardant has a good flame retardant effect; the structure contains two carboxylic acid groups, has high activity, and can be fully combined with organic functional groups in nylon 66 salt, so that the carboxylic acid groups are well grafted to a nylon main chain, and the flame retardance of the flame-retardant nylon resin is improved.

(2) The additive amount of the flame retardant is small, so that the mechanical property of the nylon is hardly influenced, and a good flame retardant effect is achieved; the flame-retardant nylon resin is directly polymerized to prepare the flame-retardant nylon by a one-step method, so that the performance reduction of the nylon and the cost problem caused by the performance reduction of the nylon due to the subsequent flame-retardant modification of the nylon are effectively avoided; the preparation method has the advantages of unique concept, simple and convenient steps and great use value.

Drawings

FIG. 1 is a Thermogravimetric (TG) graph of the flame retardant nylon resins of examples 1-3 and comparative example;

FIG. 2 is a DSC chart of the flame retardant nylon resins of examples 1 to 3 and comparative example.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.