阅读说明：本技术 聚天门冬氨酸酯及其制备方法以及在密封涂料中的应用 (Polyaspartic acid ester, preparation method thereof and application thereof in sealing coating ) 是由 张武军 王书传 梁上海 陈鸿栅 于 2021-08-18 设计创作，主要内容包括：本发明公开一种聚天门冬氨酸酯,所述聚天门冬氨酸酯由2,4-二胺基-3,5-二甲硫基甲苯和3,3’-二甲基-4,4’-二氨基-二环己基甲烷的混合物与马来酸二乙酯聚合而成。本发明还公开了这种聚天门冬氨酸酯的制备方法和以这种聚天门冬氨酸酯为原料的密封涂料。本发明公开的聚天门冬氨酸酯中2,4-二胺基-3,5-二甲硫基甲苯增加韧性和拉伸强度,同时3,3’-二甲基-4,4’-二氨基-二环己基甲烷的苯环结构具有抗电子活化效应,具有优异的耐γ射线辐照性能。本发明公开的密封涂料兼具柔韧性和强度,同时具有优异的耐γ射线辐照性能和屏蔽阻隔性,可以防空气泄露；同时具有耐久阻燃性,受到长时间辐照后仍有强抗火焰传播性能。(The invention discloses polyaspartic acid ester, which is prepared by polymerizing a mixture of 2, 4-diamino-3, 5-dimethylthiotoluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexyl methane with diethyl maleate. The invention also discloses a preparation method of the polyaspartic ester and a sealing coating using the polyaspartic ester as a raw material. The 2, 4-diamino-3, 5-dimethylthiotoluene in the polyaspartic acid ester disclosed by the invention increases the toughness and tensile strength, and meanwhile, the benzene ring structure of the 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane has an electron activation resistant effect and excellent gamma ray irradiation resistance. The sealing coating disclosed by the invention has the advantages of flexibility and strength, excellent gamma-ray irradiation resistance and shielding and blocking properties, and air leakage prevention; meanwhile, the flame-retardant coating has durable flame retardance and still has strong flame propagation resistance after being irradiated for a long time.)

1. A polyaspartic acid ester is characterized in that the polyaspartic acid ester is prepared by polymerizing a mixture of 2, 4-diamino-3, 5-dimethylthiotoluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane with diethyl maleate.

2. A polyaspartic acid ester as claimed in claim 1,

the molar ratio of the mixture to diethyl maleate is 2-2.3: 1;

the molar ratio of the 2, 4-diamino-3, 5-dimethylthiotoluene to the 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane is 0.5-2: 1.

3. The method of producing polyaspartic acid esters according to claim 1 or 2, comprising the steps of:

s1: fully mixing 2, 4-diamino-3, 5-dimethylthio toluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexyl methane according to a proportion, and dripping diethyl maleate into the mixture to react;

s2: and rectifying the crude product under vacuum to obtain the polyaspartic acid ester.

4. The production method according to claim 3,

in the step S1, the dripping time is not more than 2h, and the temperature is not higher than 60 ℃ during dripping;

in the step S1, the reaction is carried out for 3 to 5 hours at the temperature of 57 to 63 ℃, then the reaction is continued at the temperature of 75 to 85 ℃, the progress of the addition reaction is tracked in the reaction process, and the reaction is stopped when the unsaturated value is measured to be 6.5 to 6.8 mg/g;

in step S2, the rectification temperature is 75-85 ℃ and the time is 20-40 min.

5. A sealing coating for a containment vessel, characterized in that its raw material comprises the polyaspartic acid ester according to claim 1 or 2.

6. The sealing coating as claimed in claim 5, which is prepared from the following raw materials in parts by weight:

7. the seal coating according to claim 6, wherein the reactive phosphate flame retardant is a polyol phosphate or a polyol phosphite, and the hydroxyl group content is 2-8%.

8. The seal coating according to claim 6 or 7, wherein the boron nitride powder is hexagonal boron nitride and has a specific surface area of 7.0 to 9.0m²/g。

9. The sealing coating of any one of claims 6-8, wherein the filler comprises at least one of talc, quartz powder, titanium dioxide, the reinforcing fiber comprises at least one of mineral fiber and carbon fiber, and the wetting dispersant comprises a gemini or non-ionic wetting dispersant.

10. A sealing coating according to any of claims 6 to 9, characterised in that the curing agent is at least one of isocyanurate and biuret isocyanate.

Technical Field

The invention relates to the field of nuclear power protective coatings, in particular to polyaspartic acid ester, a preparation method thereof and application thereof in sealing coatings.

Background

Containment is the most important barrier to isolate the reactor of the nuclear island system from the outside, and is generally composed of a reinforced concrete structure (cylinder wall) and a steel lining. Because the concrete has the characteristic of porosity, the coating is required to be adopted as a sealing material on the surface of the concrete of the containment vessel to prevent nuclear radiation pollution from leaking from the containment vessel, so that the damage of the structure exposed to radiation for a long time is avoided, and the nuclear radiation pollutants on the surface are easy to remove.

However, the current sealing coating for concrete containment has the following problems: (1) after the material is irradiated, the tensile strength and the elastic elongation are poor, and cracking and falling are easy to occur, so that the leakage rate of nuclear radioactive particles is increased; (2) non-reactive plasticizing flame retardant without hydroxyl groups, such as trichloroethyl phosphate, triisopropylphenyl phosphate and the like, is used, and is easy to have surface migration along with the increase of service life, so that the flame retardance of the sealing coating is reduced, the flame propagation rate is increased, and meanwhile, the plasticity, the strength and the elongation are reduced, and the air tightness is reduced; (3) the inorganic filler is granular or non-high-flake-diameter mica, the sealing performance is general, the air leakage rate is higher, and the air leakage rate is usually 0.2-0.5 wt%/d.

Disclosure of Invention

Therefore, the invention aims to solve the technical problems that the existing coating has radioactive leakage and reduced flame retardance when used after being radiated for a long time, and the sealing performance of the coating is poor, thereby providing polyaspartic acid ester, a preparation method thereof and application thereof in sealing coating.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

the invention provides polyaspartic acid ester, which is characterized in that the polyaspartic acid ester is prepared by polymerizing a mixture of 2, 4-diamino-3, 5-dimethylthiotoluene (DMTDA) and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane (DMDC) and diethyl maleate.

Preferably, the mass ratio of the mixture to diethyl maleate is 2-2.3: 1;

the mass ratio of the 2, 4-diamino-3, 5-dimethylthiotoluene (DMTDA) to the 3,3 '-dimethyl-4, 4' -diamino-Dicyclohexyl Methane (DMDC) is 0.5-2: 1.

The invention also provides a preparation method of the polyaspartic acid ester, which comprises the following steps:

s1: fully mixing 2, 4-diamino-3, 5-dimethylthiotoluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexyl methane according to a proportion, and dripping diethyl maleate into the mixture to react to obtain a crude product;

s2: and rectifying the crude product under vacuum to obtain the polyaspartic acid ester.

Further, it is characterized in that,

in the step S1, the dripping time is not more than 2h, and the temperature is not higher than 60 ℃ during dripping;

in the step S1, the reaction is carried out for 3 to 5 hours at the temperature of 57 to 63 ℃, then the reaction is continued at the temperature of 75 to 85 ℃, the progress of the addition reaction is tracked in the reaction process, and the reaction is stopped when the unsaturated value is measured to be 6.5 to 6.8 mg/g;

in step S2, the rectification temperature is 75-85 ℃ and the time is 20-40 min.

The invention also provides a sealing coating for a containment, which comprises the polyaspartic acid ester as the raw material.

Further, the feed comprises the following raw materials in parts by weight:

preferably, the reactive phosphate ester flame retardant is a polyol phosphate or a polyol phosphite with a hydroxyl content of 2-8%.

The boron nitride is hexagonal boron nitride and has a specific surface area of 7.0-9.0m²Has a preferred balance of dispersion stability and barrier shielding ability.

The filler comprises at least one of talcum powder, quartz powder and titanium dioxide, the reinforcing fiber comprises at least one of mineral fiber and carbon fiber, and the wetting and dispersing agent comprises at least one of gemini type and non-ionic wetting and dispersing agent.

The curing agent is at least one of isocyanurate and biuret isocyanate.

The scheme provided by the invention has the following advantages:

1. the polyaspartic acid ester provided by the invention is obtained by performing Michael addition reaction on a mixture of DMDC and DMTDA and diethyl maleate, wherein the DMDC structure endows resin with elasticity and flexibility, the DMTDA increases toughness and tensile strength, meanwhile, the benzene ring structure of the DMTDA has an electron activation effect and excellent gamma-ray irradiation resistance, and the mechanical property of the polyaspartic acid ester prepared by mixing the two materials serving as raw materials is further improved.

2. The reactive phosphate flame retardant and the curing agent in the sealing coating are crosslinked to form a film, different from a non-reactive flame retardant which can migrate and dissociate from the coating along with the increase of service life, the flame retardance and the compactness of a paint film are reduced, the coating of the coating has durable flame retardance, and the coating still has strong flame propagation resistance and airtightness after irradiation.

3. In the sealing coating provided by the invention, the chain winding density macromolecule gap after the polyaspartic acid ester isocyanate is cured and crosslinked is small, and the air tightness of a coating film is high; meanwhile, the boron nitride powder is adopted, so that the shielding and blocking performance is excellent, and the molecular gaps filled in the resin increase the air leakage prevention capacity of the paint film.

Detailed Description

The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.

The examples do not show the specific experimental steps or conditions, and can be performed according to the conventional experimental steps described in the literature in the field. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.

The raw materials used in the examples were as follows:

the reactive phosphate ester flame retardant is a product of Clariant company, the model is Exolit OP550, and specifically is polyalcohol phosphate ester;

the boron nitride powder is a product of Momentive company, and the model is CF 500;

the reinforced fiber is a product of Lapinus company, the model is CF10, and the reinforced fiber is mineral fiber;

the filler is a product of brocade titanium company, the model is CR506, and is silicon-aluminum and titanium white of a special organic surface treatment chlorination method;

the wetting dispersant is a product of Tego company, the model is Dispers 655, and the wetting dispersant is a nonionic wetting dispersant;

the isocyanurate is a product of Wanhua company, and the model is HT 100;

the biuret isocyanate is a product of Wanhua company, and the model is HB 100.

Example 1

This example provides a polyaspartic acid ester, which comprises 2mol of 2, 4-diamino-3, 5-dimethylthiotoluene, 1mol of 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane, and 1.5mol of diethyl maleate

The preparation method comprises the following steps:

1) under the protection of nitrogen, adding 2, 4-diamino-3, 5-dimethylthio toluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexyl methane into a four-mouth bottle provided with a speed-regulating stirrer, a reflux condensation dehydration device and a thermometer;

2) at normal temperature, diethyl maleate is slowly dropped in, and the temperature in the charging process is controlled not to be higher than 60 ℃. The metered diethyl maleate is completely dripped in 2 h;

3) continuously reacting for 4 hours at the temperature of 60 ℃, heating to 80 ℃, continuously keeping the reaction for 6 hours, tracking the progress of the addition reaction in the reaction process, and stopping the reaction when the unsaturated value is measured to be 6.5-6.8 mg/g;

4) rectifying at 80 deg.C under vacuum-0.09 MPa for 30min, and removing light components to obtain polyaspartic acid ester.

The present invention also provides a sealing coating material, which is prepared from 32.5kg of polyaspartic acid ester, 5kg of reactive phosphate flame retardant, 1.5kg of reinforcing fiber, 2.5kg of boron nitride powder, 7.5kg of radiation-resistant filler, 1kg of wetting dispersant, 20kg of isocyanurate and 30kg of biuret isocyanate by thoroughly mixing the above raw materials.

Example 2

This example provides a polyaspartic acid ester, which comprises 2mol of 2, 4-diamino-3, 5-dimethylthiotoluene, 1mol of 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane, and 1.5mol of diethyl maleate

The preparation method comprises the following steps:

1) under the protection of nitrogen, adding 2, 4-diamino-3, 5-dimethylthio toluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexyl methane into a four-mouth bottle provided with a speed-regulating stirrer, a reflux condensation dehydration device and a thermometer;

2) at normal temperature, diethyl maleate is slowly dropped in, and the temperature in the charging process is controlled not to be higher than 60 ℃. The metered diethyl maleate is completely dripped in 2 h;

3) continuously reacting for 4 hours at the temperature of 60 ℃, heating to 80 ℃, continuously keeping the reaction for 6 hours, tracking the progress of the addition reaction in the reaction process, and stopping the reaction when the unsaturated value is measured to be 6.5-6.8 mg/g;

4) rectifying at 80 deg.C under vacuum-0.09 MPa for 30min, and removing light components to obtain polyaspartic acid ester.

This example also provides a sealing coating, which is prepared from 41.5kg of polyaspartic acid ester, 1.5kg of reactive phosphate flame retardant, 0.5kg of reinforcing fiber, 1kg of boron nitride powder, 5kg of radiation-resistant filler, 0.5kg of wetting dispersant, 30kg of isocyanurate and 30kg of biuret isocyanate by thoroughly mixing the above raw materials.

Example 3

This example provides a polyaspartic acid ester having as starting materials 2 moles of 2, 4-diamino-3, 5-dimethylthiotoluene, 1 mole of 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane, and 1.5 moles of diethyl maleate.

The preparation method comprises the following steps:

1) under the protection of nitrogen, adding 2, 4-diamino-3, 5-dimethylthio toluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexyl methane into a four-mouth bottle provided with a speed-regulating stirrer, a reflux condensation dehydration device and a thermometer;

2) at normal temperature, diethyl maleate is slowly dropped in, and the temperature in the charging process is controlled not to be higher than 60 ℃. The metered diethyl maleate is completely dripped in 2 h;

3) continuously reacting for 4 hours at the temperature of 60 ℃, heating to 80 ℃, continuously keeping the reaction for 6 hours, tracking the progress of the addition reaction in the reaction process, and stopping the reaction when the unsaturated value is measured to be 6.5-6.8 mg/g;

4) rectifying at 80 deg.C under vacuum-0.09 MPa for 30min, and removing light components to obtain polyaspartic acid ester.

The present invention also provides a sealing coating material, which is prepared from 36.75kg of polyaspartic acid ester, 4kg of reactive phosphate flame retardant, 1kg of mineral fiber, 1.5kg of boron nitride powder, 6kg of radiation-resistant filler, 0.75kg of wetting dispersant, 20kg of isocyanurate and 30kg of biuret isocyanate by fully mixing the above raw materials.

Comparative example 1

This comparative example provides a polyaspartic acid ester mixture, which is different from example 1 in that 2, 4-diamino-3, 5-dimethylthiotoluene and 3,3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane were polymerized with diethyl maleate, respectively, to obtain two polyaspartic acid esters, and the two polyaspartic acid esters were mixed.

The raw material ratio and the preparation method are completely the same as those of the example 1.

The comparative example also provides a sealing coating, which is prepared from 32.5kg of polyaspartic acid ester, 5kg of reactive phosphate flame retardant, 1.5kg of reinforcing fiber, 2.5kg of boron nitride powder, 7.5kg of radiation-resistant filler, 1kg of wetting dispersant, 20kg of isocyanurate and 30kg of biuret isocyanate by fully mixing the above raw materials.

Comparative example 2

This example provides a sealing coating for a containment vessel, the only difference from example 1 is that the polyaspartate used is prepared as follows:

the raw materials comprise 1mol of 1,3-BAC (1, 3-cyclohexyldimethylamine), 2mol of MXDA (m-xylylenediamine) and 1.5mol of diethyl maleate.

The preparation method comprises the following steps:

1) under the protection of nitrogen, adding 1,3-BAC and MXDA into a four-mouth bottle provided with a speed regulation stirrer, a reflux condensation dehydration device and a thermometer;

2) at normal temperature, diethyl maleate is slowly dropped in, and the temperature in the charging process is controlled not to be higher than 60 ℃. The metered diethyl maleate is completely dripped in 2 h;

3) continuously reacting for 4h at 60 ℃, heating to 80 ℃, continuously keeping the reaction for 6 h, tracking the progress of the addition reaction in the reaction process, and stopping the reaction when the unsaturated value is 6.6-6.8 mg/g;

4) rectifying at 80 deg.C under vacuum-0.09 MPa for 30min, and removing light components to obtain polyaspartic acid ester.

The raw materials of the flame retardant are 32.5kg of polyaspartic acid ester, 5kg of reactive phosphate flame retardant, 1.5kg of reinforcing fiber, 2.5kg of boron nitride powder, 7.5kg of radiation-resistant filler, 1kg of wetting dispersant, 20kg of isocyanurate and 30kg of biuret isocyanate, and the preparation method is to fully mix the raw materials to obtain the flame retardant.

Comparative example 3

This comparative example used a commercially available polycaprolactone polyurethane coating, specifically Bydur 6405 coating from Xinhe corporation.

Comparative example 4

The only difference between this comparative example and example 1 is the use of a non-reactive flame retardant, specifically triisopropylphenyl phosphate.

Test examples

The irradiation-resistant air leakage-proof high-toughness coating obtained in examples 1 to 5 of the present invention and the comparative example coating were subjected to performance tests, and the test results are shown in table 1:

wherein the tensile strength, elastic elongation, air leakage, flame spread and stain removal test data are values after irradiation test according to NB/T20133.3 standard.

TABLE 1 results of Performance test of examples 1-5 and comparative examples

As can be seen from the table above, the embodiment of the application has high mechanical property, and meanwhile, the air leakage rate and the flame propagation rate are low; in comparative example 1, a sealing coating prepared by using a mixture of two polyaspartates, only DMDC or DMTDA, as raw materials, has a decreased tensile strength and elongation as compared to example 1; the raw material of the polyaspartic ester adopted in the comparative example 2 does not contain DMDC or DMTDA, the tensile strength of the prepared sealing coating is obviously lower than that of the comparative example 1 and is far lower than the data of the application example 1, and the mechanical property of the coating prepared by the comparative example 3 is obviously lower than that of the application example after long-time irradiation; comparative example 3 is a polycaprolactone polyurethane coating sold in the market, and after long-time irradiation, the coating has low air leakage rate and flame propagation rate which are obviously not in accordance with the requirements except that the mechanical property is far lower than that of the coating in the embodiment; comparative example 4 although only the flame retardant was changed as compared with example 1, the entire system was destroyed after a long-term irradiation because of the free precipitation of the flame retardant, so that the tensile strength, elongation, flame retardancy, etc. were significantly lower than those of example 1.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.