阅读说明：本技术 一种噁唑烷类潜固化剂及其制备方法及其应用 (Oxazolidine latent curing agent, and preparation method and application thereof ) 是由 周建 刘高旗 于 2020-12-31 设计创作，主要内容包括：一种噁唑烷类潜固化剂及其制备方法及其应用,所述噁唑烷类潜固化剂命名为2-异丙基-3-羟乙基-1,3-噁唑烷,化学结构式为：本发明中的噁唑烷类潜固化剂,在单组分聚氨酯体系的配方中使用量小,经济成本低。该噁唑烷分子中有一个自由的羟基,在与聚氨酯预聚体混合后可发生接枝反应而连在一起,从而使其分散更均匀,混合后的单组分聚氨酯体系更稳定,延长材料的储存应用时间。(An oxazolidine latent curing agent, a preparation method and application thereof, wherein the oxazolidine latent curing agent is named as 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine, and the chemical structural formula is as follows:)

1. An oxazolidine latent curing agent, characterized in that: the oxazolidine latent curing agent is named as 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine, and the chemical structural formula is as follows:

2. a preparation method of oxazolidine latent curing agent is characterized in that: comprises the following steps:

step 1: adding 90-110 parts by weight of diethanolamine and 60-150 parts by weight of organic solvent into a reaction kettle, uniformly stirring, heating to 40-60 ℃, then dropwise adding 60-80 parts by weight of isobutyraldehyde, and carrying out heat preservation reaction for 0.5-2 hours;

step 2: heating the reaction kettle to 70-90 ℃, refluxing and water dividing for 4-6 hours, cooling the feed liquid to room temperature, and heating to evaporate the organic solvent;

and step 3: and (3) carrying out reduced pressure fractionation on the feed liquid after water separation, collecting fractions at 120 ℃ under vacuum of 60Pa, and obtaining colorless transparent liquid 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine.

3. The method for preparing an oxazolidine latent curing agent according to claim 2, wherein the organic solvent is at least one of cyclohexane, benzene and toluene.

4. A one-component polyurethane material characterized by: the raw material formula of the single-component polyurethane material comprises the following raw materials in parts by weight: 25 to 35 parts by weight of polymer polyol, 3 to 6 parts by weight of diisocyanate, 1 to 2 parts by weight of oxazolidine latent curing agent according to claim 1, 0.1 to 0.4 part by weight of catalyst, and 0.1 to 0.5 part by weight of antioxidant.

5. The one-component polyurethane material of claim 4, wherein: the polymer polyol is at least one of polyether polyol 2000, polyether polyol 3000, polyoxypropylene glycol, polytetrahydrofuran glycol and polycarbonate glycol.

6. The one-component polyurethane material of claim 4, wherein: the diisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate.

7. The one-component polyurethane material of claim 4, wherein: the catalyst is at least one of dibutyltin dilaurate, triethylamine and stannous octoate.

Technical Field

The invention belongs to the technical field of polyurethane auxiliaries, and particularly relates to an oxazolidine latent curing agent, and a preparation method and application thereof.

Background

In recent years, polyurethane materials such as polyurethane waterproof coatings, adhesives, sealants and the like are widely applied to industries such as industrial buildings, national defense and military industry, automobile manufacturing, decoration and the like due to excellent structures and performances of the polyurethane materials. Compared with the traditional double-component polyurethane system, the single-component polyurethane does not need to add other cross-linking agents, chain extenders and other auxiliary agents when in use, can be cross-linked and cured only by water vapor in the air, and has simple construction and wide practicability.

The curing mechanism of the one-component polyurethane is: after the isocyanate group-terminated polyurethane prepolymer is contacted with air, the isocyanate group reacts with water vapor in the air to form a film through crosslinking. The carbon dioxide gas generated during the curing process can form bubbles and pores in or on the surface of the material, and the problem is a great defect for the use appearance and the mechanical property of the material. Adding calcium oxide, calcium hydroxide and the like into the single-component polyurethane to react with carbon dioxide; or the addition of activated carbon, molecular sieves and the like for adsorbing carbon dioxide can not effectively eliminate bubbles inside and outside the material, and can also greatly reduce the mechanical property of the material.

The oxazolidine is used as a latent curing agent of the polyurethane prepolymer, so that the foaming problem of the single-component polyurethane material can be solved from the source. The curing mechanism of the oxazolidine latent curing agent is as follows: in a dry and sealed environment, the latent curing agent and the polyurethane prepolymer can stably coexist; in a wet environment, oxazolidine preferentially reacts with water to generate beta-alcohol amine containing amino and hydroxyl, and the beta-alcohol amine reacts with isocyanate groups in the prepolymer to generate carbamate and carbamido, so that no gas is generated in the curing process, and the structural defects of air holes, bubbles and the like of the material are thoroughly overcome.

If the molecular weight of the oxazolidine latent curing agent is too high, the using amount of the oxazolidine latent curing agent is large, and the economic cost is high; on the other hand, if the molecular weight is too low, the compatibility of the polyurethane prepolymer is poor, and aggregation or precipitation phenomena can occur in a single-component polyurethane system, so that the defoaming is not uniform and the defoaming effect is poor, and the service performance of the material is further influenced.

Disclosure of Invention

The invention aims to provide an aromatic diamine curing agent and a preparation method thereof.

In order to achieve the above objects and other related objects, the present invention provides the following technical solutions: an oxazolidine latent curing agent is named as 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine, and the chemical structural formula is as follows:

in order to achieve the above objects and other related objects, the present invention provides the following technical solutions: a preparation method of oxazolidine latent curing agent comprises the following steps:

step 1: adding 90-110 parts by weight of diethanolamine and 60-150 parts by weight of organic solvent into a reaction kettle, uniformly stirring, heating to 40-60 ℃, then dropwise adding 60-80 parts by weight of isobutyraldehyde, and carrying out heat preservation reaction for 0.5-2 hours;

step 2: heating the reaction kettle to 70-90 ℃, refluxing and water dividing for 4-6 hours, cooling the feed liquid to room temperature, and heating to evaporate the organic solvent;

and step 3: and (3) carrying out reduced pressure fractionation on the feed liquid after water separation, collecting fractions at 120 ℃ under vacuum of 60Pa, and obtaining colorless transparent liquid 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine.

The preferable technical scheme is as follows: the organic solvent is at least one of cyclohexane, benzene and toluene.

In order to achieve the above objects and other related objects, the present invention provides the following technical solutions: a raw material formula of the single-component polyurethane material comprises the following raw materials in parts by weight: 25 to 35 parts by weight of polymer polyol, 3 to 6 parts by weight of diisocyanate, 1 to 2 parts by weight of oxazolidine latent curing agent according to claim 1, 0.1 to 0.4 part by weight of catalyst, and 0.1 to 0.5 part by weight of antioxidant.

The preferable technical scheme is as follows: the polymer polyol is at least one of polyether polyol 2000, polyether polyol 3000, polyoxypropylene glycol, polytetrahydrofuran glycol and polycarbonate glycol.

The preferable technical scheme is as follows: the diisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate.

The preferable technical scheme is as follows: the catalyst is at least one of dibutyltin dilaurate, triethylamine and stannous octoate.

Due to the application of the technical scheme, compared with the prior art, the invention has the advantages that:

the oxazolidine latent curing agent is named as 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine, and has small usage amount and low economic cost in the formula of a single-component polyurethane system. The oxazolidine molecule has one free hydroxyl group, and may be grafted to link together after being mixed with polyurethane prepolymer, so as to disperse homogeneously, stabilize the mixed single component polyurethane system and prolong the storage and application time of the material.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

Example 1: oxazolidine latent curing agent, and preparation method and application thereof

A preparation method of oxazolidine latent curing agent comprises the following specific steps:

(1) adding 90 parts by mass of diethanolamine and 100 parts by mass of organic solvent cyclohexane into a reaction kettle, uniformly stirring, heating to 50 ℃, dropwise adding 60 parts by mass of isobutyraldehyde, and carrying out heat preservation reaction for 0.5 hour;

(2) heating the reaction kettle to 75 ℃, refluxing and dividing water for 4 hours, finishing dividing water when the water yield reaches or approaches to a theoretical value, cooling the feed liquid to room temperature, heating to evaporate the organic solvent, and recycling;

(3) and (3) carrying out reduced pressure fractionation on the feed liquid after water separation, collecting fractions at 120 ℃ under vacuum of 60Pa, and obtaining 130 parts by mass of colorless transparent liquid 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine.

The oxazolidine is used as a latent curing agent to be applied to a single-component polyurethane material.

The single-component polyurethane film material is prepared from the following raw materials in parts by mass:

example 2: oxazolidine latent curing agent, and preparation method and application thereof

A preparation method of oxazolidine latent curing agent comprises the following specific steps:

(1) adding 100 parts by mass of diethanolamine and 120 parts by mass of organic solvent toluene into a reaction kettle, uniformly stirring, heating to 50 ℃, dropwise adding 70 parts by mass of isobutyraldehyde, and carrying out heat preservation reaction for 1 hour;

(2) heating the reaction kettle to 90 ℃, refluxing and dividing water for 6 hours, finishing dividing water when the water yield reaches or approaches to a theoretical value, cooling the feed liquid to room temperature, heating to evaporate the organic solvent, and recycling;

(3) and (3) carrying out reduced pressure fractionation on the feed liquid after water separation, collecting fractions at 120 ℃ under vacuum of 60Pa, and obtaining 150 parts by mass of colorless transparent liquid 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine.

The oxazolidine is used as a latent curing agent to be applied to a single-component polyurethane material.

The single-component polyurethane film material is prepared from the following raw materials in parts by mass:

comparative example 1

The comparative example provides a single-component polyurethane film material, oxazolidine latent curing agent is not used, the mass parts of other raw materials are consistent with those of the example 1, and the mixture ratio is as follows:

mechanical property tests are carried out on the single-component polyurethane adhesive films provided in the embodiments 1-2 and the comparative example 1, the test method is carried out according to the standard GB/T16777-2008, and specific test results are shown in Table 1.

TABLE 1

Example 3: oxazolidine latent curing agent, and preparation method and application thereof

An oxazolidine latent curing agent is named as 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine, and the chemical structural formula is as follows:

a preparation method of oxazolidine latent curing agent comprises the following steps:

step 1: adding 110 parts by weight of diethanolamine and 150 parts by weight of organic solvent into a reaction kettle, uniformly stirring, heating to 60 ℃, then dropwise adding 80 parts by weight of isobutyraldehyde, and carrying out heat preservation reaction for 2 hours;

step 2: heating the reaction kettle to 90 ℃, refluxing and dividing water for 6 hours, cooling the feed liquid to room temperature, and heating to evaporate the organic solvent;

and step 3: and (3) carrying out reduced pressure fractionation on the feed liquid after water separation, collecting fractions at 120 ℃ under vacuum of 60Pa, and obtaining colorless transparent liquid 2-isopropyl-3-hydroxyethyl-1, 3-oxazolidine.

The preferred embodiment is: the organic solvent is cyclohexane and benzene, and the weight ratio of the organic solvent is 1: 1 by volume ratio.

A raw material formula of the single-component polyurethane material comprises the following raw materials in parts by weight: 35 parts by weight of polymer polyol, 6 parts by weight of diisocyanate, 2 parts by weight of oxazolidine latent curing agent according to claim 1, 0.4 part by weight of catalyst, and 0.1 to 0.5 part by weight of antioxidant.

The polymer polyol is polyether polyol 2000, polyether polyol 3000 according to a weight ratio of 1: 1, and mixing the components in a mass ratio of 1.

The diisocyanate is toluene diisocyanate.

The preferable technical scheme is as follows: the catalyst is dibutyltin dilaurate.

The foregoing is illustrative of the preferred embodiment of the present invention and is not to be construed as limiting thereof in any way, and any modifications or variations thereof that fall within the spirit of the invention are intended to be included within the scope thereof.