阅读说明：本技术 一种环氧树脂固化剂及其制备方法与应用 (Epoxy resin curing agent and preparation method and application thereof ) 是由 豆海娟 于 2020-07-02 设计创作，主要内容包括：本发明公开了一种环氧树脂固化剂及其制备方法与应用,涉及有机材料技术领域,本发明利用二乙烯三胺和N-(P-马来酰亚胺基苯基)异氰酸酯制备出新型环氧树脂固化剂,该环氧树脂固化剂在对环氧树脂进行固化后,能够显著提高固化后环氧树脂的阻燃性能,极限氧指数LOI达到32％以上,同时还能使环氧树脂的耐热性得到提高,玻璃化转变温度Tg达到200℃以上,从而扩宽了环氧树脂的使用范围。(The invention discloses an epoxy resin curing agent and a preparation method and application thereof, and relates to the technical field of organic materials, the invention utilizes diethylenetriamine and N- (P-maleimide phenyl) isocyanate to prepare a novel epoxy resin curing agent, the epoxy resin curing agent can obviously improve the flame retardant property of the cured epoxy resin after curing the epoxy resin, the limit oxygen index LOI reaches more than 32%, meanwhile, the heat resistance of the epoxy resin can be improved, and the glass transition temperature Tg reaches more than 200 ℃, thereby widening the application range of the epoxy resin.)

1. An epoxy resin curing agent, which is characterized in that: is obtained by the reaction of diethylenetriamine and N- (P-maleimide phenyl) isocyanate, and the structural formula is as follows:

2. the process for producing an epoxy resin curing agent according to claim 1, wherein: adding N- (P-maleimide phenyl) isocyanate into diethylenetriamine, stirring and mixing, adding a catalyst, heating for reaction, carrying out reduced pressure distillation after the reaction is finished, collecting unreacted diethylenetriamine, continuing raising the temperature after the diethylenetriamine is collected, and collecting fractions with the boiling point of 218-219 ℃ to obtain the epoxy resin curing agent.

3. The method for producing an epoxy resin curing agent according to claim 2, characterized in that: the molar ratio of the diethylenetriamine to the N- (P-maleimide phenyl) isocyanate is 1-1.5: 1.

4. The method for producing an epoxy resin curing agent according to claim 2, characterized in that: the dosage of the catalyst is 3-8% of the total mass of the diethylenetriamine and the N- (P-maleimide phenyl) isocyanate.

5. The method for producing an epoxy resin curing agent according to claim 2, characterized in that: the catalyst is an organic bismuth catalyst.

6. An epoxy resin composition comprising the epoxy resin curing agent prepared according to any one of claims 2 to 5, characterized in that: the epoxy resin composition comprises bisphenol A epoxy resin and an epoxy resin curing agent, wherein the molar ratio of epoxy groups in a bisphenol A epoxy resin structure to primary amine groups in an epoxy resin curing agent structure is 1:1, and the curing is carried out for 2-4h at the temperature of 150 ℃.

7. An epoxy resin coating comprising the epoxy resin curing agent prepared according to any one of claims 2 to 5, characterized in that: the epoxy resin coating comprises a component A and a component B, wherein the component A is prepared from the following raw materials in parts by weight: 40-70 parts of bisphenol A type epoxy resin, 10-30 parts of filler, 1-5 parts of ultraviolet absorber, 1-5 parts of defoaming agent, 1-5 parts of flatting agent and 20-50 parts of diluent; the component B is prepared from the following raw materials in parts by weight: 20-50 parts of epoxy resin curing agent and 20-50 parts of diluent; the mass ratio of the component A to the component B is 3-5: 1.

8. The epoxy resin coating according to claim 7, characterized in that: the filler is one or more of mica powder, kaolin, talcum powder and calcium carbonate; the defoaming agent is a polysiloxane defoaming agent; the leveling agent is a BYK type leveling agent; the diluent is one or more of dimethylbenzene and butyl acetate.

9. The epoxy resin coating according to claim 7, characterized in that: the ultraviolet absorbent is ultraviolet absorbent UV-531 or 1, 3-dimethyl-2-phenyl-2-phosph-imidazolidine.

The technical field is as follows:

the invention relates to the technical field of organic materials, in particular to an epoxy resin curing agent, and a preparation method and application thereof.

Background art:

the epoxy resin curing agent is an additive which reacts with epoxy resin to form a net-shaped three-dimensional polymer, and the composite material aggregate is wrapped in a net-shaped body to change linear resin into tough body-shaped solid.

The amine curing agent belongs to a common epoxy resin curing agent, and the curing effect of primary amine and secondary amine on epoxy resin is to open an epoxy group by active hydrogen on a nitrogen atom to enable the epoxy group to be crosslinked and cured. Aliphatic polyamines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, diethylaminopropylamine and the like have high activity and can crosslink and cure the epoxy resin at room temperature; aromatic polyamines, such as m-phenylenediamine, are less reactive and can be cured completely at 150 ℃.

At present, the commonly used amine curing agent can cure the epoxy resin, and has no obvious improvement effect on the flame retardance of the prepared resin material. Epoxy resin belongs to flammable polymer, and in order to expand the application range of epoxy resin, the flame retardant property of the system needs to be optimized. At the present stage, a common optimization mode is to add a flame retardant, and the flame retardant can only improve the flame retardant performance of the system generally, and can only improve the glass transition temperature of the system rarely so that the system has good high temperature resistance.

The patent CN 107022063A discloses a flame-retardant epoxy resin curing agent prepared by reacting diaminobenzhydrylamine and triethyl phosphate, and a modified epoxy resin prepared by diphenylmethane bismaleimide and diaminodiphenylmethane, and the flame-retardant epoxy resin curing agent and the modified epoxy resin are cured to obtain the flame-retardant high-Tg epoxy resin, wherein the glass transition temperature Tg reaches 153.4-190.2 ℃, and the limiting oxygen index LOI reaches 30.9-35.4. This patent mentions "in paragraph [0017] that the present invention introduces a large amount of rigid groups such as imide structure, benzene ring in the epoxy resin system, and furthermore the system can form a triazine ring structure having high heat resistance after curing, so that the Tg of the system can be greatly increased. And the phosphorus element is added into the system, and the phosphorus compound can promote strong dehydration reaction among molecules when being heated, so that a compact carbon layer can be formed during combustion of the system to achieve the purpose of isolating oxygen for flame retardance, and the introduction of the diphenylmethane bismaleimide in the system is also added with the nitrogen element which can perform a synergistic flame retardance effect on the system with the phosphorus element. "therefore, the Tg and LOI of the system are improved depending on the synergistic effect of the flame-retardant epoxy resin curing agent and the modified epoxy resin, that is, if the flame-retardant epoxy resin curing agent prepared by the flame-retardant epoxy resin curing agent is added into the conventional epoxy resin, the technical effect of simultaneously and obviously improving the Tg and LOI of the system can not be expected at all.

The invention content is as follows:

the technical problem to be solved by the invention is to provide a novel epoxy resin curing agent, which can obviously improve the flame retardant property of the cured epoxy resin and improve the heat resistance of the epoxy resin after the epoxy resin is cured.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

an epoxy resin curing agent is obtained by reacting diethylenetriamine with N- (P-maleimide phenyl) isocyanate, and the structural formula is as follows:

the preparation method of the epoxy resin curing agent comprises the following steps: adding N- (P-maleimide phenyl) isocyanate into diethylenetriamine, stirring and mixing, adding a catalyst, heating for reaction, carrying out reduced pressure distillation after the reaction is finished, collecting unreacted diethylenetriamine, continuing raising the temperature after the diethylenetriamine is collected, and collecting fractions with the boiling point of 218-219 ℃ to obtain the epoxy resin curing agent.

The molar ratio of the diethylenetriamine to the N- (P-maleimide phenyl) isocyanate is 1-1.5: 1.

The dosage of the catalyst is 3-8% of the total mass of the diethylenetriamine and the N- (P-maleimide phenyl) isocyanate.

The catalyst is an organic bismuth catalyst.

The invention also provides an epoxy resin composition containing the epoxy resin curing agent prepared by the technical scheme, which comprises the following specific components:

an epoxy resin composition comprises bisphenol A epoxy resin and an epoxy resin curing agent, wherein the molar ratio of epoxy groups in a bisphenol A epoxy resin structure to primary amine groups in an epoxy resin curing agent structure is 1:1, and the curing is carried out for 2-4h at the temperature of 150 ℃.

Further, the invention also provides an epoxy resin coating containing the epoxy resin curing agent prepared by the technical scheme, wherein the epoxy resin coating comprises a component A and a component B, and the component A is prepared from the following raw materials in parts by weight: 40-70 parts of bisphenol A type epoxy resin, 10-30 parts of filler, 1-5 parts of ultraviolet absorber, 1-5 parts of defoaming agent, 1-5 parts of flatting agent and 20-50 parts of diluent; the component B is prepared from the following raw materials in parts by weight: 20-50 parts of epoxy resin curing agent and 20-50 parts of diluent; the mass ratio of the component A to the component B is 3-5: 1.

The filler is one or more of mica powder, kaolin, talcum powder and calcium carbonate.

The defoaming agent is a polysiloxane defoaming agent.

The leveling agent is a BYK type leveling agent.

The diluent is one or more of dimethylbenzene and butyl acetate.

The ultraviolet absorbent is ultraviolet absorbent UV-531 or 1, 3-dimethyl-2-phenyl-2-phosph-imidazolidine.

The invention has the beneficial effects that: the novel epoxy resin curing agent is prepared by using diethylenetriamine and N- (P-maleimide phenyl) isocyanate, and after the epoxy resin is cured, the flame retardant property of the cured epoxy resin can be obviously improved, the limit oxygen index LOI reaches more than 32%, the heat resistance of the epoxy resin can be improved, and the glass transition temperature Tg reaches more than 200 ℃, so that the application range of the epoxy resin is widened.

The specific implementation mode is as follows:

in order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.