CN114940736A - Cycloaliphatic imine latent curing agent and preparation method and application thereof - Google Patents

Abstract

The invention discloses an alicyclic imine latent curing agent and a preparation method and application thereof. The preparation method includes: in an environment where nitrogen is evacuated to air, 10-30 parts by weight of alicyclic primary amine and 0.5-5 parts by weight of catalyst A are mixed and stirred and heated to 40-120° C., and then 5-5 parts by weight are added dropwise. 30 parts by weight of aldehyde/ketone compounds were incubated for 6-15 hours; the reaction solution was allowed to stand for a certain period of time, the water generated by the reaction was removed, and the catalyst A was filtered and recovered to obtain a crude product; the crude product was subjected to atmospheric distillation and The excess aldehyde/ketone compound is recovered by the step pressure swing distillation method combined with the reduced pressure distillation, and the water and other impurities are distilled off at the same time to obtain a high-purity alicyclic imine latent curing agent. The alicyclic imine latent curing agent prepared by the above method can not only be applied to the one-component moisture-curing polyurethane system, but also can solve the foaming problem of the polyurethane system during the moisture-curing process, and can also be applied to the two-component polyurethane system etc. products.

Description

A kind of alicyclic imine latent curing agent and preparation method and application thereof

technical field

The invention relates to a curing agent, in particular to an alicyclic imine latent curing agent and a preparation method thereof, belonging to the technical field of polymer chemistry.

Background technique

In recent years, new polyurethane materials such as polyurethane waterproof coatings and sealing adhesives have developed rapidly, especially single-component moisture-curing polyurethane (SPU) materials, because SPU does not need to add additional crosslinking agents or curing agents and other auxiliary materials during use. That is, there are no problems of metering error and mixing uniformity of each component, and it can be quickly cured only by trace moisture in the air, which greatly reduces the difficulty of construction, so its application range and fields are particularly wide.

Limited by its own curing mechanism, the isocyanate group-terminated SPU prepolymer will generate CO ₂ gas during the moisture curing process, and defects such as pores and bubbles on the surface or inside of the material will seriously affect its appearance and mechanical properties. The removal of _CO2 gas by adding defoamer or adsorbent has limited effect, and the addition of these materials can also reduce the usability and stability of SPU materials. The use of latent curing agent in the SPU prepolymer can eliminate the _CO2 generation in the SPU material from the source. Wherein, the curing mechanism of (aldehyde) imine latent curing agent is as following reaction formula:

R ₁ -CH=NRN=CH-R ₁ +2H ₂ O→H ₂ NR-NH ₂ +2R ₁ CHO

The latent curing process and application advantages of imine latent curing agent in one-component polyurethane materials, the introduction of patents CN107043447A and CN109251292A: imine because two amine groups are hidden, good fluidity at room temperature, very easy to mix with SPU, sealing It has long storage stability under anhydrous conditions; imine preferentially reacts with H ₂ O in the air to form a primary amino group, and the primary amino group reacts with the isocyanate group (NCO group) of SPU for chain extension reaction. During the whole reaction process No CO ₂ gas is generated, which can prevent the occurrence of blistering of SPU materials, and at the same time, the appearance and some mechanical properties of the material are also greatly improved.

Therefore, the development of latent curing agents suitable for SPU systems has become a hot spot in the research and development of polyurethane curing agents at home and abroad.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a latent curing agent suitable for SPU system in order to overcome the deficiencies of the prior art.

In order to achieve the above purpose, the technical scheme adopted in the present invention is: a preparation method of an alicyclic imine latent curing agent, the preparation method comprising the following steps:

Under the environment of nitrogen evacuating air, 10-30 parts by weight of primary alicyclic amine and 0.5-5 parts by weight of catalyst A are mixed and stirred and heated to 40-120°C, and then 5-30 parts by weight of aldehyde is added dropwise / Ketone compounds, the reaction is incubated for 6-15 hours;

The reaction solution is allowed to stand for a certain period of time, the water generated by the reaction is removed, and the catalyst A is recovered by filtration to obtain a crude product;

The step-type pressure swing distillation method combining atmospheric distillation and vacuum distillation is carried out to the crude product to recover excess aldehyde/ketone compounds, and simultaneously distill off water and other impurities to obtain high-purity alicyclic imines latent curing agent.

In a specific embodiment of the present invention, the alicyclic primary amine is o-diamine methylcyclopentane, methylcyclopentanediamine, methylcyclohexanediamine, 1,3-bis(aminomethyl) ring At least one of hexane, isophoronediamine, and cyclohexylamine.

In a specific embodiment of the present invention, the aldehyde/ketone compound is acetone, butanone, pentanone, cyclohexanone, cyclopentanone, acetophenone, pinacolone, formaldehyde, acetaldehyde, propionaldehyde, isobutyl At least one of aldehyde, n-butyraldehyde, benzaldehyde, salicylaldehyde, furfural, and cinnamaldehyde.

In a specific embodiment of the present invention, the catalyst A is an acidic resin. For example, the acidic resin is at least one of zeolite solid acid, heteropolyacid solid acid, and cation exchange resin.

In a specific embodiment of the present invention, the molar ratio of the amino group of the alicyclic primary amine to the carbonyl group of the aldehyde/ketone compound is 1:1-1:4; preferably, the molar ratio of the amino group to the carbonyl group is 1 :1.05-1:1.25.

The present invention also provides an alicyclic imine latent curing agent, which is prepared by the above-mentioned preparation method of the alicyclic imine latent curing agent of the present invention; the Alicyclic imine latent curing agent.

The present invention also provides a one-component polyurethane material. The raw material of the one-component polyurethane material is composed of the following raw materials in parts by weight: 250-350 parts by weight of oligomer polyol, 30-60 parts by weight of polyisocyanate, 30-60 parts by weight of imine 10-20 parts by weight of the latent curing agent, 2-5 parts by weight of the catalyst B, and 2-6 parts by weight of the anti-aging agent; wherein, the above-mentioned alicyclic imine type latent curing agent of the present invention.

In a specific embodiment of the present invention, the oligomer polyol is polyoxypropylene glycol, polytetrahydrofuran glycol, tetrahydrofuran-propylene oxide copolyether, polyester polyol, polycaprolactone glycol, polycarbonate At least one of diol, polybutadiene polyol, polyacrylate polyol; preferably, the oligomer polyol used is polyoxypropylene diol, polytetrahydrofuran diol, polycaprolactone diol, At least one of polycarbonate diols.

In a specific embodiment of the present invention, the polyisocyanate is toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate At least one of diisocyanate and p-phenylene diisocyanate; preferably, the polyisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.

In a specific embodiment of the present invention, the catalyst B is at least one of dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, triethylamine, and triethylenediamine.

In a specific embodiment of the present invention, the antioxidant used is at least one of antioxidant-264, antioxidant 1010, phenothiazine, light stabilizer UV-9, UV-24, and UV-328.

The invention adopts alicyclic primary amine and aldehyde/ketone compound as raw materials, and reacts under certain conditions to prepare alicyclic imine latent curing agent. The alicyclic imine latent curing agent can not only be applied to one-component moisture-curing polyurethane systems, but also can solve the foaming problem of polyurethane systems during moisture-curing, such as one-component polyurethane coatings, one-component polyurethane adhesives Adhesives, one-component polyurethane sealants, etc., can also be used in two-component polyurethane systems and other products.

Detailed ways

The preferred embodiments of the present invention will be described in detail below.

Example 1

The present embodiment provides a preparation method of an alicyclic imine latent curing agent, and the specific steps are:

128g of methylcyclohexanediamine and 5.5g of catalyst A (macroporous sulfonic acid type cation exchange resin) were added to a reaction kettle, the air in the still was evacuated with nitrogen, stirred and heated to 70-85°C, Then start to drip 240g of pinacolone, and keep the reaction at this temperature for 10 hours; after the insulation is completed, the feed liquid in the reactor is left to stand for stratification for 20 minutes, remove the water generated by the reaction, and filter and recover the catalyst A to obtain the The crude amine product; then the crude product is subjected to a stepped pressure swing distillation method combining atmospheric distillation and reduced pressure distillation to recover excess pinacolone, and to distill off other impurities to obtain a colorless transparent liquid, about 269g , that is, alicyclic imine latent curing agent.

The above-mentioned alicyclic imine is used as a latent curing agent in a one-component polyurethane material. Calculated by mass percentage, the formula of the one-component polyurethane material is composed of the following raw materials: 40% polyether glycol PPG2000, 42% polyether diol PPG2000, 42% Polyether diol PTMG2000, 12% toluene diisocyanate (TDI-80), 4% alicyclic imine latent curing agent, 0.8% catalyst B dibutyltin dilaurate (T12), 1.2% Antioxidant 1010.

The preparation method of the above single-component polyurethane material is specifically as follows: according to the mass fraction in the formula, add PPG2000 and PTMG2000 into a three-necked flask, heat and stir to disperse evenly, vacuum dehydration at 105 ° C for 1 hour; add when cooling to 80 ° C TDI-80 and catalyst B T12 were stirred and reacted for 3 hours; when the temperature was lowered to 60 ℃, the above-mentioned alicyclic imine latent curing agent and antioxidant 1010 were added, and after rapid stirring for 5 minutes, vacuum defoaming was performed for 10 minutes. use.

Example 2

The present embodiment provides a preparation method of an alicyclic imine latent curing agent, and the specific steps are:

170g of isophorone diamine and 8g of catalyst A (macroporous sulfonic acid type cation exchange resin) were added to a reactor, the air in the reactor was evacuated with nitrogen, stirred and heated to 40～55°C, then Begin to drip the isobutyraldehyde of 173g, and heat insulation reaction at this temperature for 12 hours; After the insulation is finished, the feed liquid in the reactor is left to stand for stratification for 20 minutes, remove the water generated by the reaction, and obtain imine after filtration and recovery of catalyst A Crude product; then carry out the step-type pressure swing distillation method that atmospheric distillation and vacuum distillation are combined to the crude product to recover excess isobutyraldehyde, and simultaneously distill other impurities to obtain a colorless transparent liquid, about 256g, That is, alicyclic imine latent curing agent.

The above-mentioned alicyclic imine is used as a latent curing agent in a one-component polyurethane material. Calculated by mass percentage, the formula of the one-component polyurethane material is composed of the following raw materials: 35% polyether glycol PPG2000, 45% polyether diol PPG2000, 45% Polyether diol PTMG2000, 14% diphenylmethane diisocyanate (liquefied MDI), 4% alicyclic imine latent curing agent, 0.8% catalyst B dibutyltin dilaurate (T12), 1.2 % Antioxidant 1010.

The preparation method of the above single-component polyurethane material is specifically as follows: according to the mass fraction in the formula, add PPG2000 and PTMG2000 into a three-necked flask, heat and stir to disperse evenly, vacuum dehydration at 105 ° C for 1 hour; add when cooling to 75 ° C Liquefy MDI and catalyst B T12, stir and react for 3 hours; add the above-mentioned alicyclic imine latent curing agent and antioxidant 1010 when the temperature is lowered to 60°C, stir rapidly for 5 minutes, vacuum degas for 10 minutes, and seal with nitrogen for later use .

Example 3

The present embodiment provides a preparation method of an alicyclic imine latent curing agent, and the specific steps are:

Add 142g of 1,3-bis(aminomethyl)cyclohexane and 7g of macroporous sulfonic acid type cation exchange resin into a reaction kettle, pass nitrogen to empty the air in the kettle, stir and heat to 40-50 ℃, then start to drip the n-butyraldehyde of 165g, and at this temperature insulation reaction 8 hours; After insulation finishes, the feed liquid in the reaction kettle is left to stand for stratification 20 minutes, remove the water that the reaction generates, filter and reclaim after catalyst A Obtain the imine crude product; then carry out the step pressure swing distillation method that atmospheric distillation and vacuum distillation are combined to the crude product to reclaim excessive n-butyraldehyde, and simultaneously distill off other impurities to obtain a colorless transparent liquid, About 230g, namely alicyclic imine latent curing agent.

The above-mentioned alicyclic imine is used as a latent curing agent in a one-component polyurethane material, and the formula of the one-component polyurethane material is composed of the following raw materials by mass percentage: 43% polyether glycol PPG2000, 43% polyether diol PPG2000, 43% Polyether diol PTMG2000, 9% isophorone diisocyanate (IPDI), 3% alicyclic imine latent curing agent, 0.8% catalyst B dibutyltin dilaurate (T12), 1.2% Antioxidant 1010.

The preparation method of the above single-component polyurethane material is specifically as follows: according to the mass fraction in the formula, add PPG2000 and PTMG2000 into a three-necked flask, heat and stir to disperse evenly, vacuum dehydration at 105 ° C for 1 hour; add when cooling to 85 ° C IPDI and catalyst B T12 were stirred and reacted for 3 hours; when the temperature was lowered to 60° C., the above-mentioned alicyclic imine latent curing agent and antioxidant 1010 were added, and after rapid stirring for 5 minutes, vacuum defoaming was performed for 10 minutes, and nitrogen was filled and sealed for use.

Example 4 (comparative example)

A one-component polyurethane material, as a comparison sample, no alicyclic imine latent curing agent is added, and only a small amount of moisture in the air is used for curing and sample preparation. Calculated by mass percentage, the formula of the one-component polyurethane material is composed of the following raw materials: 45% polyether diol PPG2000, 40% polyether diol PTMG2000, 13% toluene diisocyanate (TDI-80), 0.8 % of catalyst B dibutyltin dilaurate (T12), 1.2% of antioxidant 1010.

The preparation method of the above single-component polyurethane material is specifically as follows: according to the mass fraction in the formula, add PPG2000 and PTMG2000 into a three-necked flask, heat and stir to disperse evenly, vacuum dehydration at 105 ° C for 1 hour; add when cooling to 80 ° C TDI-80 and catalyst B T12 were stirred and reacted for 3 hours; when the temperature was lowered to 60 °C, antioxidant 1010 was added, and after rapid stirring for 5 minutes, vacuum degassing was performed for 10 minutes, and nitrogen was filled and sealed for use.

Example 5 (comparative example)

This comparative example provides an alicyclic imine latent curing agent, which is basically the same as Example 1, except that the amount of methylcyclohexanediamine as a synthetic raw material is 130 g, and the amount of pinacolone is 220 g; The macroporous sulfonic acid type cation exchange resin was used, and the addition amount was reduced to 4g.

The alicyclic imine prepared in this example is used as a latent curing agent in a one-component polyurethane material, and the formula, dosage and preparation method of the one-component polyurethane material are the same as those in Example 1.

Example 6 (comparative example)

This comparative example provides an alicyclic imine latent curing agent, which is basically the same as that in Example 1, except that the consumption of methylcyclohexanediamine as a synthetic raw material is 140 g, and the consumption of pinacolone is 200 g; The basic catalyst sodium methoxide was used, and the addition amount was 7 g.

The alicyclic imine prepared in this example is used as a latent curing agent in a one-component polyurethane material, and the formula, dosage and preparation method of the one-component polyurethane material are also the same as those in Example 1.

The single-component polyurethane glue prepared in the above-mentioned Examples 1-6 was poured into a square mold with a thickness of about 1.5 mm in a square mold sprayed with a mold release agent in advance, and wetted under the conditions of a temperature of 25 ° C and a relative humidity of 50%. Air-cured, and the mechanical properties were tested after 7 days of curing. The tensile strength and elongation at break were measured according to the method of GB/T 528-2009, and the Shore A hardness was measured according to the method of GB/T 531-1999. According to GB/T 13477.5-2002 method B to test the surface dry time, according to GB/T 32369-2015 method 2 to measure the cured thickness of the glue sample after 3 days of preparation to characterize its curing speed.

The test results are shown in Table 1.

Table 1

serial number project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 1 Hardness/Shore A 70 69 68 72 69 70 2 Curing speed/mm 2.69 2.57 2.61 1.83 2.31 1.97 3 Dry time/h 19 17 18 43 26 33 4 Tensile strength/MPa 14.57 14.08 14.33 12.46 13.65 12.88 5 Elongation at break/% 549 655 621 268 423 393

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement them accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (10)

1. A preparation method of a cycloaliphatic imine latent curing agent comprises the following steps:

under the environment of nitrogen gas and air evacuation, 10-30 parts by weight of alicyclic primary amine and 0.5-5 parts by weight of catalyst A are mixed, stirred and heated to 40-120 ℃, then 5-30 parts by weight of aldehyde/ketone compound are dripped, and the heat preservation reaction is carried out for 6-15 hours;

standing the reaction solution for a certain time, removing water generated by the reaction, and filtering and recovering the catalyst A to obtain a crude product;

and (3) carrying out a stepped pressure-variable distillation mode combining atmospheric distillation and reduced pressure distillation on the crude product to recover excessive aldehyde/ketone compounds, and simultaneously distilling to remove water and other impurities to obtain the high-purity alicyclic imine latent curing agent.

2. The production method according to claim 1, wherein the alicyclic primary amine is at least one of o-diaminomethylcyclopentane, methylcyclopentanediamine, methylcyclohexanediamine, 1, 3-bis (aminomethyl) cyclohexane, isophoronediamine, and cyclohexylamine.

3. The production method according to claim 1, wherein the aldehyde/ketone compound is at least one of acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, acetophenone, pinacolone, formaldehyde, acetaldehyde, propionaldehyde, isobutyraldehyde, n-butyraldehyde, benzaldehyde, salicylaldehyde, furfural, and cinnamaldehyde.

4. The production method according to claim 1, wherein the catalyst a is an acidic resin;

preferably, the acidic resin is at least one of zeolite solid acid, heteropoly acid solid acid and cation exchange resin.

5. The production method according to claim 1, wherein the molar ratio of the amino group of the alicyclic primary amine to the amino group/carbonyl group of the aldehyde/ketone compound is 1:1 to 1: 4.

6. A cycloaliphatic imine latent curing agent prepared by the preparation method according to any one of claims 1 to 5; the purity of the alicyclic imine latent curing agent is more than 95%.

7. The single-component polyurethane material comprises the following raw materials in parts by weight: 350 parts of oligomer polyol 250, 30-60 parts of polyisocyanate, 10-20 parts of imine latent curing agent, 2-5 parts of catalyst B and 2-6 parts of anti-aging agent;

wherein the latent hardener of the imine group is the latent hardener of the alicyclic imine group according to claim 6.

8. The one-component polyurethane material of claim 7, wherein the oligomer polyol is at least one of polyoxypropylene glycol, polytetrahydrofuran glycol, tetrahydrofuran-propylene oxide copolyether, polyester polyol, polycaprolactone diol, polycarbonate diol, polybutadiene polyol, polyacrylate polyol.

9. The one-component polyurethane material of claim 7, wherein the polyisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate, and p-phenylene diisocyanate.

10. The one-component polyurethane material of claim 7, wherein the catalyst B is at least one of dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, triethylamine, triethylenediamine;

preferably, the anti-aging agent is at least one of antioxidant 264, antioxidant 1010, phenothiazine, light stabilizer UV-9, UV-24 and UV-328.