Preparation method and application of polyaspartic acid ester resin

Abstract

The invention belongs to the technical field of polymer preparation, and particularly relates to a preparation method and application of polyaspartic acid ester resin. The invention aims to overcome the defect that the curing time of a polyaspartic acid ester resin polyurea material is difficult to control in the prior art, and provides a polyaspartic acid ester resin for polyurea and a preparation method of the polyaspartic acid ester resin for polyurea. And adding the diester maleate B, and carrying out a secondary reaction to obtain the polyaspartic acid ester resin. The processing technology is simple, and the prepared polyurea has the advantages of moderate curing time and high strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer preparation, and particularly relates to a preparation method and application of a polyaspartate ester resin. Background Art

[0002] The technology of spray polyurea elastomer, as a new type of solvent-free and highly reactive green spraying process, has received extensive attention in recent years in multiple fields such as construction, anti-corrosion, and waterproofing. This technology stands out with its characteristics of environmental protection and pollution-free, and rapid curing, becoming a very attractive alternative to traditional coatings. However, despite its many advantages, the application of traditional polyurea materials also faces some challenges.

[0003] Polyaspartate ester (PAE) polyurea, as the third-generation polyurea material, is a new material developed after aromatic and aliphatic polyureas. Compared with traditional polyureas, it has a longer curing time. Although this characteristic brings some challenges in certain aspects, it also endows it with some unique advantages. First of all, the longer curing time means that polyaspartate ester polyurea has a longer pot life and curing time. This characteristic makes the construction process more flexible, allowing construction workers more time to adjust the thickness and uniformity of the coating, so as to obtain better surface effects and higher construction quality. In addition, due to the relatively mild reaction, polyaspartate ester polyurea can be constructed under a wider range of environmental conditions, including applications at lower temperatures. This not only expands its scope of application but also improves the success rate of construction under adverse environmental conditions. At the same time, this mild reaction characteristic reduces the problem of concentrated heat release caused by rapid reaction, avoiding defects such as pitting and orange peel on the coating surface, and further improving the quality and aesthetics of the coating. Moreover, the longer curing time of PAE polyurea helps to achieve one-time construction of thicker coatings without sagging, which is an important advantage for application scenarios that require thick coating protection.

[0004] However, despite the above advantages, the longer curing time of polyaspartate ester polyurea materials does bring a series of challenges. In principle, the curing reaction of polyaspartate ester polyurea is much milder than that in traditional polyureas, so it takes longer to complete cross-linking to form a network structure. This means that in order to achieve ideal physical properties, polyaspartate ester polyurea requires a longer gel time and curing time. In addition, environmental factors such as temperature and humidity also affect its curing speed. Lower temperature or higher humidity may further extend its curing time because these conditions slow down the speed of chemical reactions.

[0005] Excessively long curing times also pose disadvantages. It reduces construction efficiency. During multi-layer coating processes, longer waiting times are required between each layer before the next layer can be sprayed, thus increasing the total cost. During construction, additional temporary protection measures may also be needed for the newly sprayed polyaspartic ester polyurea coating to prevent damage to the incompletely cured coating, which also increases complexity and cost. The industry has been exploring ways to optimize the synthesis process to obtain a controllable and appropriate curing time to meet increasingly stringent industrial standards and market demands. Summary of the Invention

[0006] The object of the present invention is to overcome the disadvantage in the prior art that the curing time of polyaspartic ester resin polyurea materials is difficult to control, and to provide a polyaspartic ester resin for polyurea and its preparation method. The processing technology of the present invention is simple, and the polyurea prepared therefrom has the advantages of a moderate curing time and high strength.

[0007] The present application provides a method for preparing a polyaspartic ester resin, comprising the following steps: S1. Drop maleic acid diester into aliphatic diamine, control the temperature at 40 - 70 °C, and the reaction time is 4 - 6 hours; S2. Heat the product obtained in step S1 to 50 - 80 °C for curing, and the reaction time is 2 - 6 hours.

[0008] S3. Drop maleic acid diester B into the product obtained in S2, control the temperature at 40 - 70 °C, and the reaction time is 4 - 6 hours, then heat it to 50 - 80 °C for curing, and the reaction time is 2 - 6 hours.

[0009] Furthermore, the maleic acid diester and maleic acid diester B are one or several of dimethyl maleate, diethyl maleate, and dibutyl maleate.

[0010] Furthermore, the aliphatic diamine is a polypropylene oxide compound capped with a primary amino group, and its molecular weight is 100 - 500.

[0011] Furthermore, the molar ratio of the aliphatic diamine, maleic acid diester, and maleic acid diester B is 1:0.4 - 0.7:0.3 - 0.6, preferably 1:0.7:0.3.

[0012] Furthermore, the polyaspartic ester obtained in the present application is mixed with hexamethylene diisocyanate trimer in a molar ratio of 1:1, stirred evenly, then vacuum degassed, and cured at room temperature to obtain polyaspartic ester polyurea.

[0013] The beneficial effects of the present invention are: By gradually dropping the diester maleate into the aliphatic diamine while maintaining the temperature at 40 - 70 °C, this process not only effectively controls the reaction rate, preventing out - of - control phenomena caused by overly rapid reactions, but also reduces the viscosity, improving the safety and controllability of the operation.

[0014] Subsequently, the reaction product is heated to 50 - 80 °C for curing for 2 - 6 hours. The main purpose of this stage is to further promote the cross - linking and polymerization between reactants and perfect the molecular chain structure. Appropriate heat treatment helps to form a more robust molecular network, thereby enhancing the mechanical strength and durability of the final product. At the same time, it also improves the surface leveling property of the coating and the adhesion to the substrate.

[0015] To achieve more precise molecular structure regulation, another portion of the diester maleate is added to the cured product, and the reaction continues for 4 - 6 hours under the same temperature conditions, and then the temperature is raised to 50 - 80 °C for a second curing treatment. This method enables the curing of the finally formed polyaspartic ester resin with the hexamethylene diisocyanate (HDI) trimer to have an appropriate curing time, having both a sufficient construction operation window period and improved efficiency.

[0016] In the whole process, the selection of materials is crucial. Dimethyl maleate, diethyl maleate, or dibutyl maleate, etc. are used as the diester maleate. These substances have a relatively small molecular weight, which helps to improve the hardness of the later products. The aliphatic diamine is selected as ZD - 123 or ZD - 140. This type of diamine contains primary amine groups and can participate in the Michael addition reaction. An appropriate amount of the diester maleate provides sufficient functional groups for subsequent cross - linking reactions without making the reaction too intense; at the same time, the amount of the aliphatic diamine ensures that there are enough amine groups participating in the reaction to form a stable PAE structure. A reasonable selection and ratio of raw materials can not only ensure product quality but also effectively control production costs and improve economic benefits.

[0017] In the preparation method of the polyaspartic ester of the present invention, in the selection of the aliphatic diamine and the diester maleate, reaction raw materials with a relatively small molecular weight are selected, which is beneficial to the improvement of the hardness of the later products; controlling the dropping rate and the reaction temperature effectively inhibits the formation of crystals. The curing reaction time of the polyaspartic ester prepared by this method with the hexamethylene diisocyanate (HDI) trimer is controlled at about one hour, which not only gives enough operation time but also does not make the curing time too long to increase the time cost, and retains the high - strength advantage of the polyaspartic ester polyurea, reducing the operation difficulty and expanding the application scope of the product. Specific embodiments

[0018] The technical solution and its effects of the present invention will be further described below through specific embodiments. The following embodiments are only used to illustrate the content of the present invention and do not limit the protection scope of the present invention. Simple changes made to the present invention by applying the concept of the present invention are within the scope of protection required by the present invention.

[0019] The equipment used in the preparation method of the present invention can all adopt the well-known equipment in the art. The raw materials used in the present invention are all commercially available unless otherwise specified.

[0020] The aliphatic diamines ZD-123, ZD-140 and ZD-1500 are all produced by Zibo Zhengda Polyurethane Co., Ltd.

[0021] Example 1 S1. Weigh the raw materials according to the molar ratio of ZD-123: dimethyl maleate: diethyl maleate of 1:0.7:0.3. First, add ZD-123 into the reaction vessel, and add dimethyl maleate into the dropping device. Control the dropping rate not higher than 3 g / min, and control the temperature at 40 °C for the dropping reaction.

[0022] S2. After the dropping is completed, control the temperature at 50 °C for aging for 2 hours.

[0023] S3. Add diethyl maleate into the dropping device and continue the dropping reaction, controlling the temperature at 50 °C.

[0024] S4. After the dropping is completed, raise the temperature to 60 °C for aging for 6 hours to obtain polyaspartate ester.

[0025] Example 2 S1. Weigh the raw materials according to the molar ratio of ZD-140: dimethyl maleate: diethyl maleate of 1:0.5:0.5. First, add ZD-140 into the reaction vessel, and add dimethyl maleate into the dropping device. Control the dropping rate not higher than 3 g / min, and control the temperature at 50 °C for the dropping reaction.

[0026] S2. After the dropping is completed, control the temperature at 50 °C for aging for 2 hours.

[0027] S3. Add diethyl maleate into the dropping device and continue the dropping reaction, controlling the temperature at 50 °C.

[0028] S4. After the dropping is completed, raise the temperature to 50 °C for aging for 6 hours to obtain polyaspartate ester.

[0029] Example 3 S1. Weigh the raw materials according to the molar ratio of ZD-123: dimethyl maleate: dibutyl maleate of 1:0.4:0.6. First, add ZD-123 into the reaction vessel, and add dimethyl maleate into the dropping device. Control the dropping rate not higher than 3 g / min, and control the temperature at 70 °C for the dropping reaction.

[0030] S2. After the dropping is completed, control the temperature at 80 °C for 2 hours of aging.

[0031] S3. Add dibutyl maleate to the dropping device and continue the dropping reaction, controlling the temperature at 40 °C.

[0032] S4. After the dropping is completed, raise the temperature to 80 °C for 4 hours of aging to obtain polyaspartate.

[0033] Comparative Example 1 S1. Weigh the raw materials according to the molar ratio of ZD-123:diethyl maleate of 1:1. First, add ZD-123 to the reaction vessel and diethyl maleate to the dropping device, and control the temperature at 70 °C for the dropping reaction.

[0034] S2. After the dropping is completed, raise the temperature to 80 °C for 4 hours of aging to obtain polyaspartate.

[0035] Comparative Example 2 S1. Weigh the raw materials according to the molar ratio of ZD-140:dibutyl maleate of 1:1. First, add ZD-123 to the reaction vessel and dibutyl maleate to the dropping device, and control the temperature at 60 °C for the dropping reaction.

[0036] S2. After the dropping is completed, raise the temperature to 80 °C for 4 hours of aging to obtain polyaspartate.

[0037] Comparative Example 3 S1. Weigh the raw materials according to the molar ratio of ZD-1500:diisooctyl maleate of 1:1. First, add ZD-1500 to the reaction vessel and diisooctyl maleate to the dropping device, and control the temperature at 60 °C for the dropping reaction.

[0038] S2. After the dropping is completed, raise the temperature to 80 °C for 4 hours of aging to obtain polyaspartate.

[0039] Comparative Example 4 S1. Weigh the raw materials according to the molar ratio of ZD-1500:diethylhexyl maleate of 1:1. First, add ZD-1500 to the reaction vessel and diethylhexyl maleate to the dropping device, and control the temperature at 60 °C for the dropping reaction.

[0040] S2. After the dropping is completed, control the temperature at 80 °C for 4 hours of aging to obtain polyaspartate.

[0041] Table 1 shows the properties of the polyaspartate obtained in each example and comparative example and the samples cured with HDI trimer.

[0042]

Claims

1. A preparation method of a polyaspartate ester resin, characterized in that: It includes the following steps: S1. Drop maleic acid diester into aliphatic diamine, control the temperature at 40 - 70 °C, and the reaction time is 4 - 6 hours; S2. Heat the product obtained in step S1 to 50 - 80 °C for curing, and the reaction time is 2 - 6 hours; S3. Drop maleic acid diester B into the product obtained in S2, control the temperature at 40 - 70 °C, and the reaction time is 4 - 6 hours, then heat it to 50 - 80 °C for curing, and the reaction time is 2 - 6 hours.

2. The preparation method of the polyaspartic acid ester resin according to claim 1, characterized in that: The maleic acid diester and maleic acid diester B are one or more of dimethyl maleate, diethyl maleate and dibutyl maleate.

3. The preparation method of the polyaspartic acid ester resin according to claim 1, characterized in that: The aliphatic diamine is a polypropylene oxide compound capped with primary amino groups, and the molecular weight is 100 - 500.

4. The preparation method of the polyaspartic acid ester resin according to claim 1, characterized in that: The molar ratio of the aliphatic diamine, maleic acid diester and maleic acid diester B is 1:0.4 - 0.7:0.3 - 0.

6.

5. The application of the product obtained by the preparation method of the polyaspartic acid ester resin according to any one of claims 1 - 4, characterized in that: Mix polyaspartic acid ester and hexamethylene diisocyanate trimer in a molar ratio of 1:1, stir evenly, then evacuate to remove bubbles, and cure at room temperature to obtain polyaspartic acid ester polyurea.

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