阅读说明：本技术 一种以工业废料为原料的酚醛改性胺固化剂及其制备方法 (Phenolic aldehyde modified amine curing agent taking industrial waste as raw material and preparation method thereof ) 是由 朱胜仙 张妍 王建微 于 2020-05-29 设计创作，主要内容包括：本发明提供了一种以工业废料为原料的酚醛改性胺,其包括如下原料：混酚,多聚甲醛,复配的胺,所述混酚为2,6-二甲基苯酚精馏的残液；所述复配的胺为二元胺,多乙烯多胺,氨基硫脲的混合物。本发明首次利用2.6-二甲基苯酚生产过程中的废液混酚为原料制备环氧树脂固化剂,不仅消除了焚烧所造成的环境污染、资源浪费等问题,还得到了一种低成本、环保型环氧树脂固化剂,给残液(混酚)带来了一定的经济价值。本发明所得到的酚醛胺固化剂,综合性能优异,粘度低、固化时放热峰低不易暴聚、固化物耐化学性。(The invention provides phenolic aldehyde modified amine taking industrial waste as a raw material, which comprises the following raw materials: mixed phenol, paraformaldehyde and compound amine, wherein the mixed phenol is residual liquid of 2, 6-dimethylphenol rectification; the compound amine is a mixture of diamine, polyethylene polyamine and thiosemicarbazide. The epoxy resin curing agent is prepared by using the waste liquid mixed phenol in the 2.6-dimethylphenol production process as a raw material for the first time, so that the problems of environmental pollution, resource waste and the like caused by burning are solved, the low-cost and environment-friendly epoxy resin curing agent is obtained, and a certain economic value is brought to residual liquid (mixed phenol). The phenolic aldehyde amine curing agent obtained by the invention has the advantages of excellent comprehensive performance, low viscosity, low exothermic peak during curing, difficult polymerization and chemical resistance of a cured product.)

1. The phenolic aldehyde modified amine with industrial waste as the raw material comprises the following raw materials: mixed phenol, paraformaldehyde and compound amine, wherein the mixed phenol is the rectification residual liquid of 2, 6-dimethylphenol in industrial production; the compound amine is a mixture of diamine, polyethylene polyamine and thiosemicarbazide.

2. The phenolic-modified amine of claim 1, wherein the phenolic-modified amine comprises the following raw materials by mass: 12-15 parts of mixed phenol, 3-4 parts of paraformaldehyde and 8-10 parts of compound amine.

3. The phenolic-modified amine of claim 1, wherein the diamine is selected from the group consisting of aliphatic diamines and/or aromatic diamines.

4. The phenolic-modified amine of claim 3, wherein the aliphatic diamine is at least one member selected from the group consisting of ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, and hexamethylene diamine; the aromatic diamine is at least one selected from p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 1, 5-naphthalenediamine, 1, 2-naphthalenediamine and 2, 3-naphthalenediamine.

5. The phenolic-modified amine of claim 1, wherein the polyethylene polyamine is at least one member selected from the group consisting of diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

6. The phenolic-modified amine of claim 1, wherein the mass ratio of diamine, polyethylene polyamine and thiosemicarbazide in the formulated amine is 16-22: 5-8: 2-3.

7. The phenol-modified amine of claim 1, wherein the mixed phenol comprises 2, 6-dimethylphenol (2,6DMP), 2, 5-dimethylphenol (2,5DMP), and a cresol as a major component.

8. A process for the preparation of the phenolic modified amine of any of claims 1 to 7 comprising the steps of: heating the mixed phenol, adding the mixed amine, adding paraformaldehyde in batches, heating, keeping the temperature for reaction, and cooling after the reaction is finished to obtain the phenolic aldehyde modified amine.

9. The method according to claim 8, wherein the heating is performed at a temperature of 35 to 40 ℃; the adding in batches is divided into 3-6 batches, and the time interval of each adding is 15-30 min; the heating and heat preservation reaction refers to heating to 70-90 ℃ and reacting for 2-5 h.

10. Use of the phenolic-modified amine of any of claims 1 to 7 as a curing agent for epoxy resins.

Technical Field

The invention relates to the field of epoxy resin curing agents, in particular to a phenolic aldehyde modified amine curing agent and a preparation method thereof.

Background

Mannich modification, also called phenolic modification, is a common modification means in amine curing agents, and currently, multiple enterprises and research institutions pushVarious phenolic aldehyde modified amine curing agents are obtained. Different phenols, aldehydes and amines are synthesized to obtain amine curing agents with different structural properties. The most common is the modification of fatty amines by phenol, formaldehyde (or paraformaldehyde), commonly known as T₃₁. In which the raw materials as phenols are also expanded from phenol to hydroquinone, resorcinol, bisphenol a, cardanol, etc., but there is a fresh possibility of directly utilizing industrial waste as a source of phenol.

In the prior art, a by-product produced by phenyl phenol is adopted, and a part of the phenol is replaced by the heterophenol to be used as a raw material of phenol (Tianjin chemical industry, 3 rd year 2001, 10-11), so that the cost is reduced. On the one hand, however, the method still needs to add a certain amount of phenol, and the effect of using the hetero-phenol alone is not good; on the other hand, the obtained phenolic aldehyde modified amine curing agent and the cured epoxy resin have poor corrosion resistance, so that the application of the phenolic aldehyde modified amine curing agent and the cured epoxy resin is limited.

2.6-dimethylphenol is widely applied to the fields of food, medicine and the like as a common chemical industrial product, phenol or o-cresol is taken as a raw material, the raw material and methanol are subjected to gas phase catalytic reaction, then the raw material is rectified and purified, the purified residual liquid is called mixed phenol, the mixed phenol mainly comprises byproducts such as o-cresol, polycresol and the like in the production process of the mixed phenol, and is accompanied with side reactions such as methanol decomposition and the like, and the main components comprise 2, 6-dimethylphenol (2,6DMP), 2, 5-dimethylphenol (2,5DMP) and polycresol. At present, the purified residual liquid (mixed phenol) is treated by burning, and the treatment mode causes resource waste on one hand and environmental pollution on the other hand.

The 2, 6-dimethylphenol rectification device produces the residual liquid of the rectification of the by-products, namely, the mixed phenol is evaluated as solid waste by a ring and requires incineration treatment. On the one hand, waste is caused, and on the other hand, the treatment cost is high. If the phenolic aldehyde modified amine curing agent can be changed into valuable, the phenolic aldehyde modified amine curing agent can be used as a raw material of the phenolic aldehyde modified amine curing agent, thereby achieving multiple purposes. The industrial waste mixed phenol generated by rectifying the 2, 6-dimethylphenol is used as a raw material to prepare the amine curing agent, and reports are not found before.

Disclosure of the invention

The epoxy resin curing agent which is low in cost, environment-friendly, corrosion-resistant, long in operation time and excellent in comprehensive performance can be obtained by taking the phenol mixed with the residual liquid of rectification of 2, 6-dimethylphenol as a raw material, carrying out Mannich reaction (man's reaction for short) with formaldehyde and compound amine and carrying out proper treatment.

The phenolic aldehyde modified amine with industrial waste as the raw material comprises the following raw materials: mixed phenol, paraformaldehyde and compound amine, wherein the mixed phenol is the rectification residual liquid of 2, 6-dimethylphenol in industrial production; the compound amine is a mixture of diamine, polyethylene polyamine and thiosemicarbazide.

Further, the phenolic aldehyde modified amine comprises the following raw materials in parts by mass: 12-15 parts of mixed phenol, 3-4 parts of paraformaldehyde and 8-10 parts of compound amine.

Further, the diamine is selected from aliphatic diamine and/or aromatic diamine, and the aliphatic diamine is at least one of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine and cyclohexanediamine; the aromatic diamine is at least one selected from p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 1, 5-naphthalenediamine, 1, 2-naphthalenediamine and 2, 3-naphthalenediamine.

The polyethylene polyamine is at least one selected from diethylenetriamine, triethylene tetramine and tetraethylene pentamine.

Furthermore, in the compound amine, the mass ratio of diamine, polyethylene polyamine and thiosemicarbazide is 16-22: 5-8: 2-3.

The main components of the mixed phenol comprise 2, 6-dimethylphenol (2,6DMP), 2, 5-dimethylphenol (2,5DMP) and cresol. These phenols are complex in composition and the quality of the phenol-formaldehyde modified amine product obtained directly as a phenol raw material is poor. The inventor unexpectedly discovers that the compound amine is adopted as a raw material, namely a mixture of diamine, polyethylene polyamine and thiosemicarbazide in a certain proportion participates in the Mannich reaction, and can play a synergistic effect, so that the obtained curing agent has excellent comprehensive performance, low viscosity, low exothermic peak during curing and low possibility of sudden aggregation, and is corrosion-resistant after being cured with epoxy resin, thereby being a novel phenolic aldehyde modified amine curing agent with excellent performance, low price and convenient manufacture.

The invention also provides a preparation method of the phenolic aldehyde modified amine, which comprises the following steps: heating the mixed phenol, adding the mixed amine, adding paraformaldehyde in batches, heating, keeping the temperature for reaction, and cooling after the reaction is finished to obtain the phenolic aldehyde modified amine.

Further, in the preparation method of the phenolic aldehyde modified amine, the heating refers to heating to 35-40 ℃; the adding in batches is divided into 3-6 batches, and the time interval of each adding is 15-30 min; the heating and heat preservation reaction refers to heating to 70-90 ℃ and reacting for 2-5 h.

The invention also provides the application of the phenolic aldehyde modified amine as an epoxy resin curing agent. The mass ratio of the phenolic aldehyde modified amine to the epoxy resin is 1: 3-8.

The epoxy resin is not particularly limited, and may be an epoxy resin that is conventional in the art. Such as bisphenol a type epoxy resin, bisphenol F type epoxy resin.

Compared with the prior art, the invention has the following beneficial effects:

the invention not only eliminates the problems of environmental pollution, resource waste and the like caused by burning, but also obtains a low-cost and environment-friendly epoxy resin curing agent, and brings certain economic value to residual liquid (mixed phenol).

The inventor unexpectedly discovers that the amines of the three components in the compounded amine play a synergistic action, and the obtained phenolic aldehyde amine curing agent has excellent comprehensive performance, low viscosity, low exothermic peak during curing and difficult depolymerization, and the chemical resistance of a cured product.

Drawings

FIG. 1 is a graph showing the torque with time of curing agents obtained in example 1, example 2 and comparative example 1 to form a cured product.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the invention in any way. The starting materials described in the examples of the present invention are commercially available and, unless otherwise specified, the starting materials and methods employed are those conventional in the art.

In the embodiment disclosed by the invention, the mass fractions of the main components of the mixed phenol are as follows: 8.24% of 2, 6-dimethylphenol (2,6DMP), 8.28% of 2, 5-dimethylphenol (2,5DMP), 80.94% of polymethyl phenol and 2.54% of impurities.

The Shore hardness test method is referred to the standard GBT 2411-;

gel time test method reference GBT 12007.7-1989;

the torque tester is an RCM-3000E type resin curing tester.

Example 1

At normal temperature and normal pressure, 275g of mixed phenol is added into a four-mouth bottle with a stirrer, a thermometer, a condenser tube and a constant pressure titration funnel, the mixed phenol is heated to 35-40 ℃, 165g of compound amine mixture (the mass ratio of ethylenediamine, diethylenetriamine and thiosemicarbazide is 20:6:3) is added into the constant pressure titration funnel, and the amine mixture is quickly dripped and the temperature is controlled to be 40-55 ℃. After the dropwise addition of the amine mixture, adding 68g of paraformaldehyde four times at the temperature of 45-55 ℃, every 30 minutes, heating and maintaining after the addition of the amine mixture is completed for two hours, maintaining the reaction for 2 hours at the temperature of 70-90 ℃, cooling to 40-45 ℃ after the maintenance is completed, and filtering particle impurities by using a filter screen to obtain a reddish brown liquid as a final product.

The indexes of the obtained phenolic aldehyde modified amine curing agent product are as follows: amine value: 516 mgKOH/g; viscosity: 123mPa · s

Example 2

290g of mixed phenol are added into a four-mouth bottle with a stirring device, a thermometer, a condenser tube and a constant pressure titration funnel, 170g of compound amine mixture (wherein the mass ratio of ethylenediamine, triethylene tetramine and thiosemicarbazide is 22:5:2) is added into the constant pressure titration funnel, and the amine mixture is quickly dripped into the constant pressure titration funnel, wherein the temperature is controlled to be 40-55 ℃. After the dropwise addition of the amine mixture, adding 62g of paraformaldehyde in four times under the condition that the temperature is 45-65 ℃, after the addition of the paraformaldehyde is completed for two hours, heating and maintaining the temperature between 70-90 ℃ for two hours, after the temperature is maintained, cooling, and filtering to obtain a reddish brown liquid which is a final product.

The product indexes are as follows: amine value: 521 mgKOH/g; viscosity: 107 mPas.

Example 3

The phenolic modified amine curative was prepared according to the method and conditions of example 1, except that the amount of the formulated amine mixture was 140 g. The final product index is as follows: amine value: 475 mgKOH/g; viscosity: 98 mPas.

Example 4

The phenolic modified amine curative was prepared according to the method and conditions of example 1, except that the compounded amine mixture was used in an amount of 200 g. The final product index is as follows: amine value: 523 mgKOH/g; viscosity: 1325 mPas.

Example 5

The phenolic aldehyde modified amine curing agent is prepared according to the method and conditions of example 1, except that in the compounded amine, the mass ratio of the ethylenediamine, the diethylenetriamine and the thiosemicarbazide is 24:5: 3. The final product index is as follows: amine value: 493 mgKOH/g; viscosity: 221 mPas.

Example 6

The phenolic aldehyde modified amine curing agent is prepared according to the method and conditions of example 1, except that in the compounded amine, the mass ratio of the ethylenediamine, the diethylenetriamine and the thiosemicarbazide is 16:8: 3. The final product index is as follows: amine value: 532 mgKOH/g; viscosity: 527 mPa.s.

Comparative example 1

The phenolic modified amine curative was prepared according to the method and conditions of example 1 except that the formulated amine was not used and instead an equivalent mass of ethylene diamine was used.

Comparative example 2

The phenolic modified amine curative was prepared according to the method and conditions of example 1 except that the formulated amine was not used, but instead was an equivalent mass of diethylenetriamine.

Comparative example 3

The phenolic modified amine curative was prepared according to the method and conditions of example 1 except that the formulated amine was not used, but was replaced with an equal mass of thiosemicarbazide.

Comparative example 4

The phenolic modified amine curing agent was prepared according to the method and conditions of example 1, except that the formulated amine was 165g of a mixed amine of ethylenediamine and diethylenetriamine in a mass ratio of 2: 1.

Comparative example 5

A phenolic modified amine curative was prepared according to the method and conditions of example 1, except that the formulated amine was 165g of a mixed amine of ethylenediamine and thiosemicarbazide in a mass ratio of 2: 1.

In order to verify the practical effects of the present invention, the phenolic-modified amine curing agents obtained in the examples and comparative examples were subjected to comparative tests, and the test data are shown in the following table:

effect example 1 operable time

The 0164 epoxy resin and the curing agent obtained in the above examples and comparative examples are subjected to a curing reaction, the weight ratio of the 0164 epoxy resin to the curing agent is 4:1, the curing conditions are 15g (of the 0164 resin, 12g of the curing agent and 3g of the curing agent) and the gel time is tested in a constant-temperature water bath at 25 ℃, and the results are shown in the following table 1:

TABLE 1

Sample name	Gel time/min
		Example 1	32
Example 2	30
		Example 3	29
Example 4	29
		Example 5	30
Example 6	28
		Comparative example 1	20
Comparative example 2	18
		Comparative example 3	22
Comparative example 4	24
		Comparative example 5	23

As can be seen from the data in Table 1, the curing agent obtained in the present invention has a significantly longer gel time at 25 ℃ than the comparative epoxy curing agent, indicating a longer workable time.

Effect example 2 micro-kinetic characterization

The 0164 epoxy resin and the curing agent obtained in the above examples and comparative examples are subjected to a curing reaction, wherein the weight ratio of the 0164 epoxy resin to the curing agent is 4:1, and the curing condition is 40 ℃/400min/2g (2 g of cured product, 1.6g of 0164 epoxy resin and 0.4g of curing agent). The resulting torque versus time profile of the system was tested and the results are shown in table 2 below and in figure 1:

TABLE 2

As can be seen from Table 2 and FIG. 1, the highest torque obtained by the curing agent obtained in the example of the present invention is significantly higher than that obtained in the comparative example, the curing speed is relatively gentle in the whole curing process, the exothermic peak is not severe, the gel time is relatively long, and the comprehensive curing performance is significantly improved.

Effect example 3 hardness SD of cured product

The curing reaction was carried out with 0164 epoxy resin and the curing agent obtained in the above examples and comparative examples, the weight ratio of 0164 epoxy resin to curing agent was 4:1, and the curing conditions were 25 ℃/24h/15g (resin + curing agent ═ 12g +3 g). The Shore hardness of the cured products was measured, and the results are shown in Table 3 below:

TABLE 3

The data in table 3 show that the shore hardness of the cured phenolic aldehyde modified amine epoxy hardener of the present invention has no effect.

Effect example 4 Corrosion resistance test

Carrying out curing reaction on 0164 epoxy resin and the curing agents obtained in the above examples and comparative examples, wherein the weight ratio of the 0164 epoxy resin to the curing agent is 4:1, and the curing conditions are as follows: 25 ℃/24h +60 ℃/8 h. The weight loss rate of each sample after being left in each reagent for 2 months was tested.

TABLE 4

As can be seen from the data in Table 4, the curing agent and the cured epoxy resin provided by the invention have excellent corrosion resistance, and can maintain good stability in various solvents, acids, bases and organic reagents.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.