阅读说明：本技术 一种水性双组份涂料用固化剂组合物 (Curing agent composition for water-based two-component coating ) 是由 沈岳 吕宏飞 伍宽平 沈君岱 于 2020-12-18 设计创作，主要内容包括：本发明提供的一种水性双组份涂料用固化剂,其结构式如式I所示；本发明还提供了上述水性双组份涂料用固化剂的制备方法。本发明还提供了一种水性双组份涂料用固化剂组合物。本发明制得的固化剂引入甲基(甲磺酰基)氨基甲酸对异氰酸酯进行封闭,可稳定保存,同时使用时仅需要稍加热即可实现解封,固化速度可根据加热温度控制；固化剂具有三个NCO基团,且三个NCO基团消去温度有差别,不仅能大大减少异氰酸酯的用量,而且可控制反应速度和程度。(The invention provides a curing agent for a water-based two-component coating, which has a structural formula shown as a formula I; the invention also provides a preparation method of the curing agent for the water-based two-component coating. The invention also provides a curing agent composition for the water-based two-component coating. Methyl (methylsulfonyl) carbamic acid is introduced into the curing agent prepared by the invention to seal isocyanate, so that the isocyanate can be stably stored, and meanwhile, deblocking can be realized only by slightly heating when the curing agent is used, and the curing speed can be controlled according to the heating temperature; the curing agent has three NCO groups, and the elimination temperatures of the three NCO groups are different, so that isocyanic acid can be greatly reducedThe amount of ester used and the rate and extent of reaction can be controlled.)

1. A curing agent for water-based two-component paint is characterized in that: the structural formula is shown as formula I:

2. the method for preparing the curing agent for the water-based two-component coating according to claim 1, wherein the curing agent comprises: the method comprises the following steps: dissolving triphenylmethane triisocyanate in dichloromethane, heating to 50-60 ℃, keeping the temperature constant, dripping the compound shown in formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 1-2h to obtain the compound; the reaction formula is as follows:

3. a curing agent composition for a water-based two-component coating is characterized in that: the paint is prepared from the following components in parts by weight: 2 parts of triphenylmethane triisocyanate, 2-4 parts of polyethylene glycol monomethyl ether and 1-4 parts of a compound shown in a formula I; the compound of formula I has the following structural formula:

4. the method for preparing the curing agent composition for the aqueous two-component coating according to claim 3, wherein the curing agent composition comprises: the method comprises the following steps:

(1) dissolving triphenylmethane triisocyanate in dichloromethane, heating to 50-60 ℃, keeping the temperature constant, dripping the compound shown in formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 1-2h to obtain the compound; the reaction formula is as follows:

(2) and (2) uniformly mixing the product obtained in the step (1) with triphenylmethane triisocyanate and polyethylene glycol monomethyl ether to obtain the catalyst.

5. The method for preparing the curing agent composition for the aqueous two-component coating according to claim 3, characterized in that: the weight parts of each component are as follows: 2 parts of triphenylmethane triisocyanate, 2-4 parts of polyethylene glycol monomethyl ether and 1-4 parts of a compound shown in a formula I.

Technical Field

The invention relates to the field of coating materials, and in particular relates to a curing agent composition for a water-based two-component coating, and a preparation method and application thereof.

Background

Because of the high viscosity of the water-based resin raw material and the easy resin demulsification caused by high-speed dispersion, the water-based epoxy coating is widely subjected to a water-grinding process in the manufacturing process at present. The process is complicated, the manufacturing period is long, the energy consumption is high, an auxiliary agent containing VOC needs to be added in the manufacturing process, extra water is needed, the solid content of the product is low, the ideal effect can be achieved only by coating for many times during coating construction, the energy consumption is high, the period is long, the water-based two-component coating produced by the process can only replace the coating of which the VOC is more than 420g/L and cannot replace other oily products containing VOC (the VOC is less than 420 g/L). In order to further reduce energy consumption and harmful substance emission in the production process, improve the quality of the water-based epoxy coating and realize green production, the coating production process needs to be improved urgently.

The curing reaction of the epoxy resin is realized by adding a curing agent and utilizing the reaction of certain groups in the curing agent and epoxy groups or hydroxyl groups in the epoxy resin. The curing agent is one of the key factors affecting the performance of the waterborne epoxy coating. The traditional solvent-based curing agent is difficult to be miscible with the water-based epoxy coating, so the problem can be solved only by using the water-based epoxy curing agent for a water-based epoxy system. Common aliphatic amine curing agents have large stimulation to human bodies, and simultaneously are easy to react with CO2 in the air to generate salt or absorb moisture to whiten, so that most of the practically used waterborne epoxy curing agents are addition products of polyamine and epoxy resin. However, the modified amine curing agent still has various defects, such as poor weather resistance, easy yellowing, poor flexibility and poor adhesion.

Disclosure of Invention

The technical problem is as follows: in order to overcome the defects of the prior art, the invention provides a curing agent composition for a water-based two-component coating, and a preparation method and application thereof.

The technical scheme is as follows: the invention provides a curing agent for a water-based two-component coating, which has a structural formula shown as a formula I:

the invention also provides a preparation method of the curing agent for the water-based two-component coating, which comprises the following steps: dissolving triphenylmethane triisocyanate in dichloromethane, heating to 50-60 ℃, keeping the temperature constant, dripping the compound shown in formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 1-2h to obtain the compound; the reaction formula is as follows:

the invention also provides a curing agent composition for the water-based two-component coating, which is prepared from the following components in parts by weight: 2 parts of triphenylmethane triisocyanate, 2-4 parts of polyethylene glycol monomethyl ether and 1-4 parts of a compound shown in a formula I; the compound of formula I has the following structural formula:

the invention also provides a preparation method of the curing agent composition for the water-based two-component coating, which comprises the following steps:

(1) dissolving triphenylmethane triisocyanate in dichloromethane, heating to 50-60 ℃, keeping the temperature constant, dripping the compound shown in formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 1-2h to obtain the compound; the reaction formula is as follows:

(2) and (2) uniformly mixing the product obtained in the step (1) with triphenylmethane triisocyanate and polyethylene glycol monomethyl ether to obtain the catalyst.

Preferably, the weight parts of the components are as follows: 2 parts of triphenylmethane triisocyanate, 2-4 parts of polyethylene glycol monomethyl ether and 1-4 parts of a compound shown in a formula I.

Has the advantages that: methyl (methylsulfonyl) carbamic acid is introduced into the curing agent prepared by the invention to seal isocyanate, so that the isocyanate can be stably stored, and meanwhile, deblocking can be realized only by slightly heating when the curing agent is used, and the curing speed can be controlled according to the heating temperature; the curing agent has three NCO groups, and the elimination temperatures of the three NCO groups are different, so that the use level of isocyanate can be greatly reduced, and the reaction speed and degree can be controlled.

In order to react quickly initially, the present invention also provides curing agent compositions that also include triphenylmethane triisocyanate to avoid too slow an initial reaction of the crosslinking reaction, especially at lower temperatures.

Drawings

FIG. 1 is a hydrogen spectrum of a curing agent for a water-based two-component coating.

Detailed Description

The present invention is further explained below.

Example 1

Preparation of the curing agent for the water-based two-component coating: dissolving triphenylmethane triisocyanate in dichloromethane, heating to 55 ℃, keeping the temperature constant, dripping the compound shown in the formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 1.5h to obtain the compound shown in the formula I.

264.6g of the compound of formula I, m/z 784.08 was obtained, the hydrogen spectrum of which is shown in FIG. 1.

Example 2

Preparation of the curing agent composition: uniformly mixing the compound shown in the formula I in the embodiment 1 with triphenylmethane triisocyanate and polyethylene glycol monomethyl ether to obtain the compound; the catalyst comprises 2 parts by weight of triphenylmethane triisocyanate, 3 parts by weight of polyethylene glycol monomethyl ether and 2 parts by weight of a compound shown in a formula I.

Example 3

Preparation of the curing agent for the water-based two-component coating: dissolving triphenylmethane triisocyanate in dichloromethane, heating to 50 ℃, keeping the temperature constant, dripping the compound shown in formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 2h to obtain the compound shown in formula I.

316.4g of the compound shown in the formula I, m/z 784.08 and a hydrogen spectrum are shown in figure 1.

Example 4

Preparation of the curing agent composition: uniformly mixing the compound shown in the formula I in the embodiment 1 with triphenylmethane triisocyanate and polyethylene glycol monomethyl ether to obtain the compound; the formula of the compound comprises, by weight, 2 parts of triphenylmethane triisocyanate, 2 parts of polyethylene glycol monomethyl ether and 1 part of a compound shown in a formula I.

Example 5

Preparation of the curing agent for the water-based two-component coating: dissolving triphenylmethane triisocyanate in dichloromethane, heating to 60 ℃, keeping the temperature constant, dripping the compound shown in formula II while stirring, finishing dripping within 2h, and reacting at constant temperature for 1h to obtain the compound shown in formula I.

198.1g of compound of formula I, m/z 784.08, is obtained, the hydrogen spectrum of which is shown in FIG. 1.

Example 6

Preparation of the curing agent composition: uniformly mixing the compound shown in the formula I in the embodiment 1 with triphenylmethane triisocyanate and polyethylene glycol monomethyl ether to obtain the compound; the catalyst comprises 2 parts by weight of triphenylmethane triisocyanate, 4 parts by weight of polyethylene glycol monomethyl ether and 4 parts by weight of a compound shown in a formula I.

Example 5

A batch of waterborne epoxy coatings was prepared according to the following formulation.

The properties of the waterborne epoxy coatings described above were tested and the results are shown in the following table.

	Sample 1	Sample 2	Sample 3	Sample No. 4	Sample No. 5	Sample No. 6	Comparative example 1
								Surface dry 25 deg.C (min)	30	30	30	20	20	20	30
Hard dry 25 deg.C (min)	70	70	70	60	60	60	120
								Dried bean curd at 25 deg.C (h)	2	2	2	1.5	1.5	1.5	3.5
Hardness (24h)	3H	3H	3H	3H	3H	3H	-
								Impact toughness KJ/m2	17.64	16.59	16.42	19.28	19.01	18.96	9.00
Bending strength MPa	120.45	118.64	117.91	123.64	120.58	121.67	110.00
								Flexural modulus GPa	2.69	2.61	2.58	2.76	2.71	2.69	2.50