Single-component polyurea coating

Abstract

The invention relates to the technical field of coatings, and provides a single-component polyurea coating, which is prepared from the following raw materials in parts by weight: 150 to 200 parts of polyether polyol, 60 to 80 parts of isocyanate, 20 to 35 parts of polyamine, 60 to 80 parts of filler, 0.5 to 1 part of defoaming agent, 1 to 3 parts of catalyst and 10 to 20 parts of thixotropic agent. The thixotropic agent is modified bentonite, the modified bentonite is obtained by modifying bentonite through a modifier, and the modifier is hydroxyl polydimethylsiloxane and isocyanate propyl triethoxy silane. According to the technical scheme, the problems of poor mechanical property and adhesive force of a single-component polyurea coating in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a single-component polyurea coating. Background Art

[0002] Coatings have extensive and indispensable applications in many fields such as construction, industry, and transportation. With the development of society, the requirements for coating performance are increasing. In the early days, traditional coatings such as alkyd paints and phenolic paints had certain limitations in weather resistance and corrosion resistance, and it was difficult to meet the use requirements in complex and harsh environments. Polyurea coatings came into being as a high-performance coating, which solved the shortcomings of traditional coatings in wear resistance and weather resistance; the initial polyurea coatings were mostly two-component systems, which had the advantages of rapid curing, high strength, and high elasticity, and performed well in application scenarios such as waterproofing, anti-corrosion, and wear resistance. However, two-component polyurea coatings need to be mixed on site during use, which has high requirements for construction equipment and personnel operation, and there are problems such as inaccurate mixing ratios and limited construction time. The emergence of single-component polyurea coatings is mainly to overcome the inconvenience of two-component polyurea coatings. It can be directly constructed, which greatly simplifies the construction process and improves construction efficiency. However, the mechanical properties and adhesion of single-component polyurea coatings are poor, and they are prone to blistering and shedding. Therefore, how to improve the mechanical properties and adhesion of single-component polyurea coatings is a problem that needs to be solved at present. Summary of the invention

[0003] The present invention provides a single-component polyurea coating, which solves the problem of poor mechanical properties and adhesion of the single-component polyurea coating in the related art.

[0004] The technical solution of the present invention is as follows: The present invention provides a one-component polyurea coating, comprising the following components in parts by weight: 150-200 parts of polyether polyol, 60-80 parts of isocyanate, 20-35 parts of polyamine, 60-80 parts of filler, 0.5-1 part of defoamer, 1-3 parts of catalyst, and 10-20 parts of thixotropic agent; The thixotropic agent is modified bentonite, and the modified bentonite is obtained by modifying bentonite with a modifier, and the modifier is hydroxy polydimethylsiloxane and isocyanate propyl triethoxy silane.

[0005] As a further technical solution, the amount of the modifier added is 2% to 5% of the mass of the bentonite.

[0006] As a further technical solution, the mass ratio of the hydroxy polydimethylsiloxane to isocyanate propyl triethoxy silane is 3-9:1.

[0007] In the present invention, the adhesion and mechanical properties of the polyurea coating are further improved by limiting the mass ratio of hydroxy polydimethylsiloxane to isocyanate propyl triethoxysilane to 3-9:1.

[0008] As a further technical solution, the mass ratio of the hydroxy polydimethylsiloxane to isocyanate propyl triethoxy silane is 7:1.

[0009] As a further technical solution, the preparation method of the thixotropic agent comprises the following steps: dispersing bentonite in an ethanol aqueous solution, adding a modifier for modification, and obtaining the thixotropic agent through drying.

[0010] As a further technical solution, the volume concentration of the ethanol aqueous solution is 75%.

[0011] As a further technical solution, the modification temperature is 40-50°C, and the modification time is 6-8h.

[0012] As a further technical solution, the hydroxy polydimethylsiloxane consists of a first hydroxy polydimethylsiloxane and a second hydroxy polydimethylsiloxane, and the molecular weights of the first hydroxy polydimethylsiloxane and the second hydroxy polydimethylsiloxane are different.

[0013] As a further technical solution, the molecular weight of the first hydroxy polydimethylsiloxane is 500, and the molecular weight of the second hydroxy polydimethylsiloxane is 4200.

[0014] As a further technical solution, the mass ratio of the first hydroxy polydimethylsiloxane to the second hydroxy polydimethylsiloxane is 9-14:1.

[0015] In the present invention, by limiting the mass ratio of the first hydroxy polydimethylsiloxane to the second hydroxy polydimethylsiloxane to 9-14:1, the adhesion and mechanical properties of the one-component polyurea coating are further improved.

[0016] As a further technical solution, the polyether polyol includes one or two of polyether diol and polyether triol.

[0017] As a further technical solution, the polyamine includes one or more of 4,4'-diaminodicyclohexylmethane, isophoronediamine, and meta-xylylenediamine.

[0018] As a further technical solution, the small catalyst includes one or two of bismuth isooctanoate and dibutyltin dilaurate.

[0019] As a further technical solution, the defoaming agent is a silicone defoaming agent.

[0020] As a further technical solution, the isocyanate is isophorone diisocyanate.

[0021] As a further technical solution, the filler includes one or more of white carbon black, wollastonite, and kaolin.

[0022] The present invention also provides a method for preparing a one-component polyurea coating, comprising the following steps: S1, vacuum dehydrating the hydroxyl-containing polymer, adding isocyanate to react, and obtaining a prepolymer having an isocyanate content of 4wt% to 5wt%; S2. Add polyamine, filler, defoamer, catalyst and thixotropic agent into the prepolymer and mix them. Then, seal the discharge to obtain a single-component polyurea coating.

[0023] As a further technical solution, the temperature of the vacuum dehydration is 110-120° C., and the time of the vacuum dehydration is 2-3 hours.

[0024] As a further technical solution, the reaction temperature is 70-80°C.

[0025] The working principle and beneficial effects of the present invention are: In the present invention, a one-component polyurea coating is obtained from polyether polyol, isocyanate, polyamine, filler, defoamer, catalyst and thixotropic agent, and the thixotropic agent is obtained from hydroxy polydimethylsiloxane and isocyanate propyl triethoxysilane modified bentonite, thereby improving the mechanical properties and adhesion of the one-component polyurea coating, preventing bubbling and shedding, and solving the problem of poor mechanical properties and adhesion of the one-component polyurea coating. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the following embodiments and comparative examples: Bentonite, particle size: 500 mesh; silicone defoamer, model: SI-X201, purchased from Laiyang Shengbang Silicone Technology Co., Ltd.; hydroxy polydimethylsiloxane I, molecular weight: 4200; hydroxy polydimethylsiloxane II, molecular weight: 500; Polyether diol, model: PPG-1000; polyether triol, model: TO330, were purchased from Shanghai Haoren International Trade Co., Ltd.

[0028] Example 1 A method for preparing a one-component polyurea coating comprises the following steps: S1, dehydrating 150 parts of polyether diol under vacuum at 110° C. for 3 h, then cooling to 70° C., adding 60 parts of isophorone diisocyanate to react, and obtaining a prepolymer having an isocyanate content of 4 wt%; S2, adding 20 parts of 4,4'-diaminodicyclohexylmethane, 60 parts of white carbon black, 0.5 parts of silicone defoamer, 1 part of bismuth isooctanoate, and 10 parts of thixotropic agent to the prepolymer, and sealing the discharge to obtain a single-component polyurea coating; The preparation method of a thixotropic agent comprises the following steps: adding 40 g of bentonite into 500 mL of ethanol aqueous solution (volume concentration of 75%) for dispersion, adding 0.6 g of hydroxy polydimethylsiloxane and 0.6 g of isocyanate propyl triethoxysilane for stirring, heating to 40° C., continuing stirring for 8 hours, and drying to obtain a thixotropic agent; The hydroxy polydimethylsiloxane is hydroxy polydimethylsiloxane I.

[0029] Example 2 A method for preparing a one-component polyurea coating comprises the following steps: S1, vacuum dehydrating 200 parts of polyether triol at 120° C. for 2 h, reducing the temperature to 80° C., adding 80 parts of isophorone diisocyanate to react, and obtaining a prepolymer having an isocyanate content of 4 wt%; S2, adding 35 parts of isophorone diamine, 80 parts of kaolin, 1 part of silicone defoamer, 3 parts of dibutyltin dilaurate, and 20 parts of thixotropic agent to the prepolymer, mixing, and sealing the discharge to obtain a single-component polyurea coating; The preparation method of a thixotropic agent comprises the following steps: adding 40 g of bentonite into 500 mL of ethanol aqueous solution (volume concentration of 75%) for dispersion, adding 1 g of hydroxy polydimethylsiloxane and 1 g of isocyanate propyl triethoxysilane for stirring, heating to 50° C., continuing stirring for 6 hours, and drying to obtain a thixotropic agent; The hydroxy polydimethylsiloxane is hydroxy polydimethylsiloxane I.

[0030] Example 3 The difference between this embodiment and embodiment 1 is that the added amount of hydroxy polydimethylsiloxane I is 1.1 g, and the added amount of isocyanate propyl triethoxy silane is 0.1 g.

[0031] Example 4 The difference between this embodiment and embodiment 1 is that the addition amount of hydroxy polydimethylsiloxane I is 0.9 g, and the addition amount of isocyanate propyl triethoxy silane is 0.3 g.

[0032] Example 5 The only difference between this embodiment and embodiment 1 is that the added amount of hydroxy polydimethylsiloxane I is 1.05 g, and the added amount of isocyanate propyl triethoxy silane is 0.15 g.

[0033] Example 6 The only difference between this embodiment and embodiment 1 is that the added amount of hydroxy polydimethylsiloxane I is 1.08 g, and the added amount of isocyanate propyl triethoxy silane is 0.12 g.

[0034] Example 7 The difference between this embodiment and embodiment 5 is that hydroxypolydimethylsiloxane I is replaced by an equal amount of hydroxypolydimethylsiloxane II.

[0035] Example 8 The only difference between this embodiment and embodiment 5 is that the hydroxy polydimethylsiloxane is composed of hydroxy polydimethylsiloxane II and hydroxy polydimethylsiloxane I in a mass ratio of 7:1.

[0036] Example 9 The only difference between this embodiment and embodiment 8 is that the mass ratio of hydroxypolydimethylsiloxane II to hydroxypolydimethylsiloxane I is 18:1.

[0037] Example 10 The only difference between this embodiment and embodiment 8 is that the mass ratio of hydroxypolydimethylsiloxane II to hydroxypolydimethylsiloxane I is 9:1.

[0038] Embodiment 11 The only difference between this embodiment and embodiment 8 is that the mass ratio of hydroxypolydimethylsiloxane II to hydroxypolydimethylsiloxane I is 14:1.

[0039] Comparative Example 1 The only difference between this comparative example and Example 1 is that hydroxypolydimethylsiloxane I is replaced by an equal amount of isocyanatepropyltriethoxysilane.

[0040] Comparative Example 2 The only difference between this comparative example and Example 1 is that isocyanate propyl triethoxysilane is replaced by an equal amount of hydroxy polydimethylsiloxane I.

[0041] Comparative Example 3 The only difference between this comparative example and Example 1 is that the thixotropic agent is bentonite.

[0042] The tensile strength of the one-component polyurea coatings prepared in Examples 1 to 11 and Comparative Examples 1 to 3 was tested according to the untreated tensile performance method in GB / T 16777-2008 "Test Methods for Building Waterproof Coatings", with a tensile speed of 200 mm / min; the bonding strength was tested according to Method A in GB / T 16777-2008 "Test Methods for Building Waterproof Coatings", and the test results are shown in Table 1.

[0043] Table 1 Mechanical properties test results of one-component polyurea coatings

[0044] Compared with Comparative Examples 1 to 3, the tensile strength and bonding strength of the polyurea coating prepared in Example 1 are higher than those of Comparative Examples 1 to 3, indicating that when bentonite modified by hydroxy polydimethylsiloxane and isocyanate propyltriethoxysilane is used as a thixotropic agent, the mechanical properties and adhesion of the polyurea coating can be improved.

[0045] Compared with Example 1, Examples 3 to 6 change the mass ratio of hydroxypolydimethylsiloxane and isocyanatepropyltriethoxysilane. As a result, the tensile strength and bonding strength of the polyurea coatings prepared in Examples 4 to 6 are higher than those in Example 1 and Example 3, indicating that when the mass ratio of hydroxypolydimethylsiloxane and isocyanatepropyltriethoxysilane is 3 to 9:1, the mechanical properties and adhesion of the polyurea coating can be further improved; by comparing Examples 4 to 6, it is found that the tensile strength and bonding strength of the polyurea coating prepared in Example 5 are higher than those in Example 4 and Example 6, indicating that when the mass ratio of hydroxypolydimethylsiloxane and isocyanatepropyltriethoxysilane is 7:1, the mechanical properties and adhesion of the obtained polyurea coating are higher.

[0046] Compared with Example 5, Examples 7 to 11 change the composition of hydroxypolydimethylsiloxane, and the tensile strength and bonding strength of the polyurea coatings prepared in Examples 8 to 11 are higher than those in Example 5 and Example 7, indicating that when the hydroxypolydimethylsiloxane is composed of hydroxypolydimethylsiloxane I and hydroxypolydimethylsiloxane II, the mechanical properties and adhesion of the polyurea coating can be further improved; by comparing Examples 8 to 11, it is found that the tensile strength and bonding strength of the polyurea coatings prepared in Examples 10 to 11 are higher than those in Example 8 and Example 9, indicating that when the mass ratio of hydroxypolydimethylsiloxane I and hydroxypolydimethylsiloxane II is 9 to 14:1, the mechanical properties and adhesion of the polyurea coating can be further improved.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A one-component polyurea coating, characterized in that: The raw materials include the following components in parts by weight: 150-200 parts of polyether polyol, 60-80 parts of isocyanate, 20-35 parts of polyamine, 60-80 parts of filler, 0.5-1 part of defoamer, 1-3 parts of catalyst, and 10-20 parts of thixotropic agent; The thixotropic agent is modified bentonite, and the modified bentonite is obtained by modifying bentonite with a modifier, and the modifier is hydroxy polydimethylsiloxane and isocyanate propyl triethoxy silane.

2. According to the one-component polyurea coating according to claim 1, the addition amount of the modifier is 2% to 5% of the mass of the bentonite.

3. A one-component polyurea coating according to claim 1, wherein the mass ratio of the hydroxy polydimethylsiloxane to the isocyanate propyl triethoxy silane is 3 to 9:

1.

4. The one-component polyurea coating according to claim 1, characterized in that: The hydroxy polydimethylsiloxane consists of a first hydroxy polydimethylsiloxane and a second hydroxy polydimethylsiloxane, and the molecular weights of the first hydroxy polydimethylsiloxane and the second hydroxy polydimethylsiloxane are different.

5. A one-component polyurea coating according to claim 4, characterized in that: The molecular weight of the first hydroxy polydimethylsiloxane is 500, and the molecular weight of the second hydroxy polydimethylsiloxane is 4200.

6. A one-component polyurea coating according to claim 4, characterized in that: The mass ratio of the first hydroxy polydimethylsiloxane to the second hydroxy polydimethylsiloxane is 9-14:

1.

7. The one-component polyurea coating according to claim 1, wherein the polyether polyol comprises one or both of polyether diol and polyether triol.

8. The one-component polyurea coating according to claim 1, wherein the polyamine comprises one or more of 4,4'-diaminodicyclohexylmethane, isophorone diamine, and meta-xylylenediamine.

9. The one-component polyurea coating according to claim 1, characterized in that: The catalyst includes one or both of bismuth isooctanoate and dibutyltin dilaurate.

10. The one-component polyurea coating according to claim 1, characterized in that: The defoamer is an organosilicon defoamer.

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