阅读说明：本技术 一种水性聚脲固化剂及其制备方法、应用 (Water-based polyurea curing agent and preparation method and application thereof ) 是由 易松 杨轩 徐涛 龙绪俭 熊东路 李斌仁 肖增钧 鲁晓东 于 2020-05-08 设计创作，主要内容包括：本发明属于固化剂技术领域,具体涉及一种水性聚脲固化剂及其制备方法、应用。本发明的第一个方面提供了一种水性聚脲固化剂的制备方法,包括以下步骤：S1.亲水改性剂的制备：将C2-C10多元醇与C4-C10二元羧酸或酸酐进行反应,得到亲水改性剂；S2.将亲水改性剂与含异氰酸酯的化合物进行反应,得到水性聚脲固化剂。本申请通过先将C2-C10多元醇、C4-C10二元羧酸或酸酐、叔胺化合物与异氰酸酯进行反应,得到具有优良乳化性能的水性聚脲固化剂,同时避免了大分子聚醚带来的耐水性差、硬度降低、NCO含量低的问题,而且弥补了羧酸盐乳化能力不足的缺陷。(The invention belongs to the technical field of curing agents, and particularly relates to a water-based polyurea curing agent, and a preparation method and application thereof. The first aspect of the invention provides a preparation method of a water-based polyurea curing agent, which comprises the following steps: s1, preparation of a hydrophilic modifier: reacting C2-C10 polyalcohol with C4-C10 dicarboxylic acid or anhydride to obtain a hydrophilic modifier; s2, reacting the hydrophilic modifier with a compound containing isocyanate to obtain the water-based polyurea curing agent. According to the preparation method, the C2-C10 polyhydric alcohol, the C4-C10 dicarboxylic acid or anhydride and the tertiary amine compound are reacted with the isocyanate to obtain the water-based polyurea curing agent with excellent emulsifying performance, and meanwhile, the problems of poor water resistance, low hardness and low NCO content caused by macromolecular polyether are solved, and the defect of insufficient emulsifying capacity of carboxylate is overcome.)

1. The preparation method of the water-based polyurea curing agent is characterized by comprising the following steps:

s1, preparation of a hydrophilic modifier: reacting C2-C10 polyalcohol with C4-C10 dicarboxylic acid or anhydride to obtain a hydrophilic modifier;

s2, reacting the hydrophilic modifier with a compound containing isocyanate to obtain the water-based polyurea curing agent.

2. The method for preparing the aqueous polyurea curing agent according to claim 1, wherein the C2-C10 polyol is at least one selected from the group consisting of diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol.

3. The method for preparing the aqueous polyurea curing agent according to claim 1, wherein the C4-C10 dicarboxylic acid or anhydride is at least one selected from succinic acid, glutaric acid, adipic acid, maleic anhydride, 2, 3-dimethylmaleic anhydride and 2-methylmaleic anhydride.

4. The method of preparing an aqueous polyurea curing agent according to claim 1, wherein the preparation raw material further comprises a tertiary amine compound in step S1.

5. The method for preparing an aqueous polyurea curing agent according to claim 4, wherein the pH of the tertiary amine compound is 11 to 13.

6. The method of preparing the aqueous polyurea curing agent of any one of claims 1 to 5, wherein the mass ratio of the C2-C10 polyol to the C4-C10 dicarboxylic acid or anhydride is 1: (0.9-1.1).

7. The method for preparing the aqueous polyurea curing agent according to claim 1, wherein the amount ratio of the isocyanate-containing compound to the hydrophilic modifier is (1-1.4): 1.

8. an aqueous polyurea curing agent obtained by the production method according to any one of claims 1 to 7.

9. The aqueous polyurea curing agent of claim 8, wherein the aqueous polyurea curing agent has a solid content of 100%, a viscosity (25 ℃) of 2000-3000mPa s, and an NCO mass content of 7-11%.

10. Use of the aqueous polyurea curing agent of claim 8 or 9 in an aqueous coating.

Technical Field

The invention belongs to the technical field of curing agents, and particularly relates to a water-based polyurea curing agent, and a preparation method and application thereof.

Background

In recent years, the requirement of chemical coating industry for environmental protection is higher and higher, strict environmental regulations are successively set at home and abroad to limit the emission of Volatile Organic Compounds (VOC) to the atmosphere, and the water-based coating takes water as a dispersion medium, and a chemical solvent is not needed in the production and use processes, so that the VOC is greatly reduced, the pollution is minimum, and the water-based formation of the coating is an important trend.

Polyurea has wide application as a coating with excellent comprehensive performance, so the development of water-based polyurea has important significance. At present, researchers mainly adopt a method of curing agent aquosity, namely, a molecular structure of the curing agent is modified, so that the curing agent has functions of an emulsifier and the curing agent, and the modification method can be mainly divided into a non-ionic aqueous polyurea curing agent and an anionic aqueous polyurea curing agent.

The nonionic aqueous polyurea curing agent is prepared by grafting polyether onto curing agent molecules, and the polyether is used as a hydrophilic modifier in U.S. Pat. No. 5,52696, Chinese patent No. 101381443, CN102504191A and the like, so that the aqueous polyurea curing agent is successfully prepared, but in order to obtain good water dispersibility, the polyether with large molecular weight is introduced into the system, the viscosity of the obtained curing agent system is large, the NCO content is low, and at the same time, the defects of slow drying speed, poor water resistance and low hardness of a coating film are caused by excessive introduction of hydrophilic polyether soft segments.

Compared with the prior art, the anionic water-based polyurea curing agent has the advantages of high NCO content, good water resistance and better water dispersibility, and can be stably dispersed in water under low shearing force. The hydrophilic modifier commonly used for the anionic aqueous polyurea curing agent mainly comprises a carboxylic acid type hydrophilic modifier and a sulfonic acid type hydrophilic modifier. The sulfonic acid group has large polarity and strong hydrophilicity, and a very small amount of sulfonic acid group is introduced to obtain stronger emulsifying property. European patent EP0703255, DE4433929A and U.S. Pat. No. 6,6046295 adopt micromolecule sulfonic acid such as hydroxyethanesulfonic acid and hydroxypropanesulfonic acid and macromolecule sulfonic acid such as hydroxyl-terminated polyether sulfonic acid as hydrophilic modifiers to prepare the aqueous polyurea curing agent with low viscosity and excellent water dispersibility. However, the hydroxypropanesulfonic acid is carcinogenic and harmful to human bodies, and the sulfonic acid is used as a strong acid, and the neutralized sulfonate has strong hydrophilicity and poor ester solubility, so that the neutralized sulfonate is easy to be compatible or even incompatible with other components in a system, so that the system is turbid or the coating is opaque. Compared with a sulfonic acid type hydrophilic modifier, the carboxylic acid type hydrophilic modifier has the advantages of easily available raw materials, environmental protection, good compatibility with polyisocyanate, but slightly poor emulsifying property.

Disclosure of Invention

In order to solve the above technical problems, a first aspect of the present invention provides a method for preparing an aqueous polyurea curing agent, comprising the steps of:

s1, preparation of a hydrophilic modifier: reacting C2-C10 polyalcohol with C4-C10 dicarboxylic acid or anhydride to obtain a hydrophilic modifier;

s2, reacting the hydrophilic modifier with a compound containing isocyanate to obtain the water-based polyurea curing agent.

As a preferable technical scheme, the C2-C10 polyhydric alcohol is selected from at least one of diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol.

As a preferable technical scheme, the C4-C10 dicarboxylic acid or anhydride is at least one selected from succinic acid, glutaric acid, adipic acid, maleic anhydride, 2, 3-dimethyl maleic anhydride and 2-methyl maleic anhydride.

As a preferable embodiment, in step S1, the preparation raw material further includes a tertiary amine compound.

As a preferred embodiment, the pH of the tertiary amine compound is 11 to 13.

As a preferable technical scheme, the mass ratio of the C2-C10 polyhydric alcohol to the C4-C10 dicarboxylic acid or anhydride is 1: (0.9-1.1).

As a preferred technical scheme, the quantity ratio of the isocyanate-containing compound to the hydrophilic modifier is (1-1.4): 1.

the second aspect of the invention provides the aqueous polyurea curing agent obtained by the preparation method.

As a preferable technical scheme, the solid content of the aqueous polyurea curing agent is 100 percent, the viscosity (25 ℃) is 2000-3000 mPas, and the NCO mass content is 7-11 percent.

The second aspect of the invention provides the application of the aqueous polyurea curing agent in an aqueous coating.

Has the advantages that: according to the preparation method, the C2-C10 polyhydric alcohol, the C4-C10 dicarboxylic acid or anhydride and the tertiary amine compound are reacted with the isocyanate to obtain the water-based polyurea curing agent with excellent emulsifying performance, and meanwhile, the problems of poor water resistance, low hardness and low NCO content caused by macromolecular polyether are solved, and the defect of insufficient emulsifying capacity of carboxylate is overcome.

Detailed Description

In order to solve the above problems, the present invention provides a method for preparing a water-based polyurea curing agent, comprising the steps of: s1, preparation of a hydrophilic modifier: reacting C2-C10 polyalcohol with C4-C10 dicarboxylic acid or anhydride to obtain a hydrophilic modifier;

s2, reacting the hydrophilic modifier with a compound containing isocyanate to obtain the water-based polyurea curing agent.

As a preferable embodiment, in step S1, the preparation raw material further includes a tertiary amine compound.

As a preferable technical scheme, the preparation method of the aqueous polyurea curing agent comprises the following steps:

s1, preparation of a hydrophilic modifier: reacting C2-C10 polyalcohol with C4-C10 dicarboxylic acid or anhydride, adding a tertiary amine compound, detecting the pH value to be neutral, and stopping the reaction to obtain a hydrophilic modifier;

s2, reacting the hydrophilic modifier with a compound containing isocyanate to obtain the water-based polyurea curing agent.

Step S1

The reaction temperature of the C2-C10 polyalcohol and the anhydride is 60-80 ℃.

As a preferred embodiment, the C2-C10 polyol is at least one selected from the group consisting of diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol.

As a preferred embodiment, the C4-C10 dicarboxylic acid or anhydride is at least one selected from succinic acid, glutaric acid, adipic acid, maleic anhydride, 2, 3-dimethylmaleic anhydride and 2-methylmaleic anhydride.

As a preferred embodiment, the pH of the tertiary amine compound is 11 to 13, and the test conditions of the pH are: an aqueous solution having a tertiary amine compound concentration of 5g/L and a test temperature of 20 ℃.

Further preferably, the tertiary amine compound is at least one selected from the group consisting of N, N-dimethylcyclohexylamine, N-dimethylbutylamine, 1-cyclopentyl-N, N-dimethyl-2-propylamine, and N, N-dimethylhexylamine.

As a preferred embodiment, the preparation of the hydrophilic modifier: adding C2-C10 polyalcohol into a reactor, stirring, heating to 60-80 ℃, adding C4-C10 dicarboxylic acid or anhydride for reaction, cooling to room temperature when the C4-C10 dicarboxylic acid or anhydride is detected to be less than the C4-C10 dicarboxylic acid or anhydride, then adding a tertiary amine compound, detecting the pH value to be neutral, stopping the reaction to obtain a hydrophilic modifier, wherein the C4-C10 dicarboxylic acid or anhydride is controlled to be added dropwise within 2.5 hours.

Wherein, the C4-C10 dicarboxylic acid or anhydride is detected by gas chromatography.

Preferably, the mass ratio of the C2-C10 polyhydric alcohol to the C4-C10 dicarboxylic acid or anhydride is 1: (0.9-1.1); more preferably, the mass ratio of the C2-C10 polyol to the C4-C10 dicarboxylic acid or anhydride is 1: 1.

preferably, the mass ratio of the C4-C10 dicarboxylic acid or anhydride to the tertiary amine compound is 1: (0.9-1.1); more preferably, the mass ratio of the C4-C10 dicarboxylic acid or anhydride to tertiary amine compound is 1: 1.

the "C4-C10 dicarboxylic acid or anhydride" refers to C4-C10 dicarboxylic acid or C4-C10 anhydride.

Step S2

The reaction temperature of the hydrophilic modifier and the isocyanate-containing compound is 70-90 ℃.

The isocyanate-containing compound is an isocyanate dimer and/or an isocyanate trimer; further, the isocyanate-containing compound is at least one selected from the group consisting of HDI trimer, HDI dimer, IPDI trimer, IPDI dimer, TDI dimer, HDI-TDI mixed trimer.

Further preferably, the isocyanate-containing compound is an isocyanate trimer containing no benzene ring. Such as IPDI trimer, HDI trimer.

The IPDI trimer refers to isophorone diisocyanate trimer. Isophorone diisocyanate has a cyclohexane six-membered ring structure with three methyl groups and two isocyanate groups, one of which is directly bonded to the aliphatic ring and the other of which is bonded to the aliphatic ring via a methylene group.

The HDI tripolymer is a compound obtained by trimerization of hexamethylene diisocyanate under the catalytic action.

Isocyanates can undergo self-addition reactions to form various self-polymers, including dimers, trimers, to mention a variety of polymers. Aromatic isocyanate can slowly generate dimer under high temperature due to high NCO reaction activity, and the dimer is a quaternary heterocyclic structure. Aromatic isocyanate or aliphatic isocyanate is polymerized into trimer under the action of catalyst, and the nuclear group of the trimer is isocyanurate six-membered heterocycle. The isocyanurate six-membered heterocycle is very stable, heat-resistant and flame-retardant. The most key process for producing the tripolymer is to control the contents of the tripolymer, the pentamer and the heptamer, the tripolymer has better fullness, the reaction speed of the pentamer and the heptamer is fastest in the film forming process, the pentamer and the heptamer reach the gel point firstly, but the paint film is not cured uniformly.

As a preferred embodiment, the step S2 includes: adding a compound containing isocyanate into a reaction kettle, stirring, heating to 70-90 ℃, dropwise adding the hydrophilic modifier, reacting until the NCO content reaches a theoretical value, cooling to 50 ℃, adding a terminator to terminate the reaction, and keeping the temperature for 0.5-1.5 hours to obtain the product. Wherein, nitrogen is introduced for protection in the whole reaction process; the hydrophilic modifier is dripped off within 4 hours.

Preferably, the substance ratio of the isocyanate-containing compound to the hydrophilic modifier is (1-1.4): 1.

the terminator is selected from at least one of benzoyl chloride, phosphoric acid and methyl p-toluenesulfonate.

As a preferred embodiment, the aqueous polyurea curing agent has a solids content of 100%, a viscosity (25 ℃) of 2000-3000 mPas and an NCO mass content of 7-11%.

The NCO mass content measuring method is a method commonly used in the art and is not particularly limited, and for example, a polymer to be measured is reacted with an excess of di-n-butylamine to produce urea, and the excess of di-n-butylamine is titrated with hydrochloric acid to quantitatively calculate the NCO content.

The second aspect of the invention provides a water-based polyurea curing agent obtained by the preparation method.

The third aspect of the invention provides the application of the aqueous polyurea curing agent in an aqueous coating.

Furthermore, the dosage of the aqueous polyurea curing agent is determined by the NH content of an amino component in the aqueous coating, and the aqueous polyurea curing agent is compounded according to the mass ratio of NCO to NH which is 0.8-1.4 to 1.

Further, the aqueous coating material is at least one of an aromatic polyurea resin, an aliphatic polyurea resin, and an aspartic polyurea resin. More preferably, the aqueous coating is an aspartic polyurea resin.

The aspartic polyurea resin is prepared by carrying out Michael addition reaction on a dialkyl maleate monomer and an aliphatic primary diamine monomer. By selecting different aliphatic primary diamine monomers, polyaspartic acid ester derivatives with different viscosities, different activities and equivalent weights can be obtained.

In the application, the water-based paint is F520 asparagus polyurea resin, which is purchased from Shenzhen flying Jun research, Inc.

According to the preparation method, the C2-C10 polyhydric alcohol, the C4-C10 dicarboxylic acid or anhydride and the tertiary amine compound are reacted with the isocyanate to obtain the water-based polyurea curing agent with excellent emulsifying performance, the problems of poor water resistance, low hardness and low NCO content caused by macromolecular polyether are solved, and the defect of insufficient emulsifying capacity of carboxylate is overcome; particularly, when the C2-C10 polyhydric alcohol is selected from at least one of diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol, and the C4-C10 dicarboxylic acid or anhydride is selected from at least one of maleic anhydride, 2, 3-dimethyl maleic anhydride and 2-methyl maleic anhydride, the curing agent is prepared to be used in the water-based paint, so that the water-based paint has proper drying time, and the hardness of the film reaches the H grade, and the addition of the curing agent is supposed to restrict the free rotation of the flexible macromolecules and promote the ordered arrangement of rigid chain segments; particularly, when the coating is the asparagus polyurea resin, amino groups in the molecular structure of the asparagus polyurea resin are surrounded by a space coronary steric hindrance environment, so that the film is qualified in an impact resistance test, and the film does not whiten after being soaked for 24 hours at room temperature.

The coating can be applied to the waterproof fields of reservoir dams, fan blades and the like.

The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.

In addition, the starting materials used are all commercially available, unless otherwise specified.