Application of polyether silane as and / or in preparation of titanium dioxide organic treatment agent, modified titanium dioxide and coating

Abstract

The invention relates to the technical field of modification of special titanium dioxide for temperature-resistant coatings, in particular to application of polyether silane as and / or in preparation of a titanium dioxide organic treatment agent, modified titanium dioxide and a coating. The invention provides application of polyether silane as and / or in preparation of a titanium dioxide organic treatment agent, modified titanium dioxide and a coating. According to the application of the polyether silane as and / or in preparation of the titanium dioxide organic treating agent, the polyether silane is obtained by polymerizing allyl glycidyl ether and siloxane; the siloxane is selected from one or more of trimethoxy silane, methyldimethoxy silane and heptamethyltrisiloxane. The invention further discloses a preparation method of the silicone sealant. The application performance of the titanium dioxide modified by polyether silane is similar to that of polyhydric alcohol TMP, meanwhile, the color difference delta E value of the heat resistance of dry powder of the titanium dioxide is smaller than 1.5, the temperature resistance of the titanium dioxide can be effectively improved, and the titanium dioxide can be used for temperature-resistant coatings, especially the temperature-resistant coatings.

Description

Technical Field

[0001] This invention relates to the field of titanium dioxide modification technology for heat-resistant coatings, specifically the application of polyether silane as and / or in the preparation of titanium dioxide organic treatment agents, modified titanium dioxide, and coatings. Background Technology

[0002] Powder coatings have seen rapid growth in market share due to their advantages, including being solvent-free, having no VOC emissions, producing thick coatings in a single application, allowing for the recycling of spilled paint, being environmentally friendly, and facilitating storage and transportation. Powder coatings are typically applied using electrostatic spraying, with a curing temperature usually between 150-200℃ for approximately 30 minutes. Furthermore, when the coated film is used in small household appliances, in addition to weather resistance, it must be able to withstand high temperatures of 200-300℃. Therefore, the color difference ΔE value after high-temperature aging must be less than 1.5, and the pigments used must possess good heat resistance.

[0003] Titanium dioxide accounts for over 50% of applications in the coatings industry, and most manufacturers choose polyols as the organic treatment agent. In the high-temperature environments (typically requiring resistance above 200℃) of titanium dioxide production processes (such as air jet milling and high-temperature coating) or end-use applications (such as plastics processing and coating curing), polyols are prone to decomposition or oxidation at high temperatures, potentially leading to discoloration, release of volatiles, or treatment failure. Taking the commonly used TMP as an example, TMP has a melting point of 58-65℃. Titanium dioxide treated with TMP has poor heat resistance and is unsuitable for applications with high temperature resistance requirements. Furthermore, due to the low boiling point of TMP, its high volatility during air jet milling affects the adsorption efficiency of TMP on the titanium dioxide surface.

[0004] Therefore, the organic modifier for titanium dioxide used in high-temperature resistant coatings must possess good chemical stability to prevent decomposition and subsequent failure of the titanium dioxide surface treatment. Simultaneously, the modifier should possess multiple hydroxyl structures or other active groups similar to TMP, enabling it to stably bind to the titanium dioxide surface through physical adsorption or the formation of stable chemical bonds, resulting in efficient surface coating, reducing the polar agglomeration tendency and photocatalytic activity of titanium dioxide, and improving dispersibility and hiding power. Finally, the modifier structure should possess controllable reaction properties, forming a uniform coating layer on the titanium dioxide surface without excessive cross-linking leading to powder agglomeration.

[0005] The high bond energy of the silicon-oxygen bond in organosilicon (approximately 452 kJ / mol) endows it with excellent thermal stability (temperature resistance up to 200°C and above), making it suitable for processes such as plastic extrusion and high-temperature coating curing. However, the hydrophilicity and hydrophobicity of a single organosilicon reagent cannot be balanced, making it difficult to be compatible with water-based and solvent-based coating systems. On the other hand, modified organosilicon reagents with excessive miscibility may have low surface tension and a greater tendency to stabilize foam, while those that are completely immiscible can lead to severe pinholes, craters, or even hammer marks in the coating. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide polyether silane as an application in the preparation of titanium dioxide organic treatment agents, modified titanium dioxide and coatings. The titanium dioxide modified by the polyether silane of the present invention not only has similar application performance to polyol TMP, but also has a color difference of less than ΔE value of less than 1.5 in dry powder heat resistance, which can effectively improve the temperature resistance of titanium dioxide and can be used in heat-resistant powder coatings or solvent-based coatings.

[0007] This invention provides the use of polyether silanes as and / or in the preparation of organic titanium dioxide treatment agents, wherein the polyether silanes are obtained by polymerization of allyl glycidyl ether and siloxane; the siloxanes are selected from one or more of trimethoxysilane, methyldimethoxysilane and heptamethyltrisiloxane.

[0008] The molar ratio of allyl glycidyl ether to siloxane in this invention is (1~1.5):1. Preferably, the molar ratio of allyl glycidyl ether to siloxane in this invention is (1.2~1.4):1. More preferably, the molar ratio of allyl glycidyl ether to siloxane in this invention is 1.3:1.

[0009] The preparation method of polyether silane according to the present invention includes the following steps: under the presence of a Pt catalyst, allyl glycidyl ether and siloxane are polymerized in a solvent to obtain polyether silane.

[0010] Specifically, the preparation method of polyether silane according to the present invention includes the following steps: mixing Pt-containing catalyst, allyl glycidyl ether and siloxane in a solvent, sealing and replacing the protective gas, then heating in an oil bath to carry out a polymerization reaction, condensing and refluxing, purifying, and obtaining polyether silane.

[0011] In some embodiments of the present invention, the preparation method of the polyether silane of the present invention includes the following steps: mixing a Pt-containing catalyst, allyl glycidyl ether, siloxane and solvent, sealing and purging nitrogen three times, using dimethyl silicone oil as the oil bath heat transfer medium to heat to the set temperature, carrying out the polymerization reaction in the oil bath, condensing and refluxing, filtering to remove the Pt-containing catalyst after the reaction, drying, rotary evaporation, and pumping with an oil pump for 30 minutes to obtain polyether silane.

[0012] The polymerization reaction temperature of the present invention is 80℃~120℃, and the polymerization reaction time is 1 h~8 h. Preferably, the polymerization reaction temperature of the present invention is 90℃~110℃, and the polymerization reaction time is 5 h~7 h. More preferably, the polymerization reaction temperature of the present invention is 100℃, and the polymerization reaction time is 6 h.

[0013] The Pt-containing catalyst of the present invention is selected from one or more of Speier catalyst (isopropanol chloroplatinate solution) and Karstedt catalyst (Karstedt platinum catalyst), preferably Speier catalyst; the solvent is selected from one or more of toluene and tetrahydrofuran, preferably toluene.

[0014] Based on Pt, the amount of Pt-containing catalyst used in this invention is 0.01% to 0.05% of the mass of the siloxane, preferably 0.01% to 0.03% of the mass of the siloxane, and more preferably 0.02% of the mass of the siloxane.

[0015] This invention provides modified titanium dioxide, which is obtained by modifying titanium dioxide with a titanium dioxide organic treatment agent. The titanium dioxide organic treatment agent is a polyether silane or a titanium dioxide organic treatment agent prepared from a polyether silane; the polyether silane is the same as described above and will not be repeated. The titanium dioxide is titanium dioxide coated with zirconium or aluminum. The amount of the titanium dioxide organic treatment agent used in this invention is 0.3% to 0.8% of the amount of titanium dioxide, preferably 0.3% to 0.5%.

[0016] This invention provides a method for preparing modified titanium dioxide, comprising the following steps: reacting titanium dioxide and a titanium dioxide organic treatment agent to obtain modified titanium dioxide. The titanium dioxide organic treatment agent and the titanium dioxide are the same as described above, and the amount of the titanium dioxide organic treatment agent is also the same as described above, and will not be repeated here.

[0017] Specifically, the dried titanium dioxide is crushed, and a titanium dioxide organic treatment agent is added to the crushed titanium dioxide and mixed for 1-3 minutes. After the treatment, the collected powder is then subjected to vapor powdering. In some embodiments of the present invention, the titanium dioxide is dried at 100℃-110℃ for 20-30 hours, the dried titanium dioxide is crushed, a titanium dioxide organic treatment agent is added to the crushed titanium dioxide, and the mixture is mixed using a crusher for 1-3 minutes. After the treatment, the collected powder is then subjected to vapor powdering.

[0018] This invention also provides the application of the modified titanium dioxide described above or the modified titanium dioxide obtained by the above preparation method in the preparation of coatings. Specifically, this invention provides coatings containing the modified titanium dioxide described above or the modified titanium dioxide obtained by the above preparation method. The coatings of this invention include powder coatings or solvent-based coatings. In some embodiments of this invention, the solvent-based coating includes: nitrocellulose lacquer, the modified titanium dioxide described above or the modified titanium dioxide obtained by the above preparation method, short-oil alkyd resin, solvent, and dispersant.

[0019] This invention provides a method for preparing the above-mentioned coating, comprising the following steps: mixing resin, modified titanium dioxide, and additives, or mixing resin, solvent, modified titanium dioxide, and additives to obtain a solvent. In some embodiments of this invention, modified titanium dioxide, short-oil alkyd resin, solvent, and dispersant are dispersed to obtain a short-oil alkyd resin coating paste; nitrocellulose varnish and the short-oil alkyd resin coating paste are mixed to obtain a solvent-based coating.

[0020] This invention provides the application of polyether silanes as and / or in the preparation of organic titanium dioxide treatment agents, modified titanium dioxide, and coatings. The polyether silane provided by this invention, in its application as and / or in the preparation of organic titanium dioxide treatment agents, is obtained by polymerizing allyl glycidyl ether and a siloxane; the siloxane is selected from one or more of trimethoxysilane, methyldimethoxysilane, and heptamethyltrisiloxane. Titanium dioxide modified with the polyether silane of this invention not only exhibits similar application performance to polyol TMP, but also has a color difference in dry powder heat resistance of less than ΔE value less than 1.5, effectively improving the temperature resistance of titanium dioxide, and can be used in heat-resistant powder coatings or solvent-based coatings. Detailed Implementation

[0021] This invention discloses the application of polyether silanes as and / or in the preparation of organic titanium dioxide treatment agents, modified titanium dioxide, and coatings. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art will clearly be able to modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0022] The present invention will be further described below with reference to the embodiments:

[0023] Example 1

[0024] 20 g of allyl glycidyl ether, 10 g of trimethylsilane, 6 mg of chloroplatinic acid catalyst, and 50 mL of toluene were weighed into a 100 mL round-bottom flask. A condenser was added, and a stir bar was used. After sealing, the mixture was purged with nitrogen three times and placed in an oil bath (the heat transfer medium was dimethyl silicone oil). The temperature was raised to 100 °C, and the mixture was refluxed for 6 hours. After the reaction was completed, the catalyst was removed by filtration, and the mixture was dried, rotary evaporated, and pumped with an oil pump for 30 minutes to obtain polyether silane with a yield of 89%.

[0025] Example 2

[0026] 20 g of allyl glycidyl ether, 30 g of trimethylsilane, 10 mg of chloroplatinic acid catalyst, and 50 mL of toluene were weighed into a 100 mL round-bottom flask. A condenser was added, and a stir bar was used. After sealing, the mixture was purged with nitrogen three times and placed in an oil bath (the heat transfer medium was dimethyl silicone oil). The temperature was raised to 100 °C, and the mixture was refluxed for 6 hours. After the reaction was completed, the catalyst was removed by filtration, and the mixture was dried, rotary evaporated, and pumped with an oil pump for 30 minutes to obtain polyether silane with a yield of 92%.

[0027] Example 3

[0028] Organic modification of titanium dioxide: Zirconium / aluminum coated titanium dioxide powder without organic treatment was dried in an oven at 105℃ for 24 hours. 100g of the dried powder was then crushed. 0.5g of the polyether silane organic treatment agent synthesized in Example 1 was added to the crushed powder, and the mixture was stirred using a crusher for 2 minutes. After treatment, the collected powder was subjected to air-powder processing.

[0029] Example 4

[0030] Organic modification of titanium dioxide: Zirconium / aluminum coated titanium dioxide powder without organic treatment was dried in an oven at 105℃ for 24 hours. 100 grams of the dried powder was then crushed. 0.5 grams of the polyether silane organic treatment agent synthesized in Example 2 was added to the crushed powder, and the mixture was stirred using a crusher for 2 minutes. After treatment, the collected powder was subjected to air-powder processing.

[0031] Comparative Example 1

[0032] 0.5 g of trimethylolpropane was mixed with 1.5 g of deionized water and stirred in a warm water bath to form a homogeneous, clear, transparent liquid. Zirconium / aluminum coated titanium dioxide without organic treatment was dried in an oven at 105°C for 24 hours. 100 g of the dried powder was then crushed. The transparent liquid was added to the crushed powder, and the mixture was stirred using a crusher for 2 minutes to achieve organic treatment. After treatment, the organically treated powder was collected, dried at 120°C for 4 hours, and then subjected to vaporization.

[0033] The heat resistance of the dry powder of the above-mentioned modified titanium dioxide with organic treatment agent was tested. Specifically, 5 grams of titanium dioxide were placed in a crucible and placed in a muffle furnace at 300℃ for 30 minutes. 5 grams of the same sample of untreated titanium dioxide were placed in small boxes and pressed into tablets using a tablet press. The color difference data of the powder before and after heat treatment were tested. The experimental results are shown in Table 1.

[0034] Table 1

[0035]

[0036] Add 35.5g of modified titanium dioxide (previously treated with organic agents), 8.0g of short-oil alkyd resin, 1.8g of solvent (PMA), and 1.8g of dispersant to a glass jar, and stir with a glass rod until fully wetted. Add 100g of glass beads, and then place the mixture in a mixing shaker and shake for 30 minutes to obtain a short-oil alkyd resin coating paste. After standing, take 1ml of the short-oil alkyd resin coating paste on a scraper and test its dispersibility, i.e., test the grinding fineness and coarse particles of the obtained short-oil alkyd resin coating paste. Take another clean glass jar, weigh 21.0g of nitrocellulose lacquer and 9.0g of short-oil alkyd resin coating paste into the jar, and then place them in a mixing shaker and shake for 5 minutes to obtain a solvent-based coating. Use the obtained paste to prepare a black and white cardstock paint film on an automatic coating machine. After the paint film dries, use a spectrophotometer to test the whiteness and hiding power, and a gloss meter to test the gloss of the paint film.

[0037] The experimental results are shown in Table 2:

[0038] Table 2

[0039]

[0040] The data in Tables 1 and 2 show that polyether silanes can be applied to the organic modification of titanium dioxide powder and achieve good results. At the same time, the surface properties of the powder after adding polyether segments are different from those of polyol monomers. These differences are mainly reflected in the heat resistance of dry powder, the dispersibility of solvent-based coatings, and the 60° gloss, providing new ideas and directions for further optimization of product performance.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. The application of polyether silane as and / or in the preparation of organic titanium dioxide treatment agents, characterized in that, The polyether silane is obtained by polymerization of allyl glycidyl ether and siloxane; The siloxane is selected from one or more of trimethoxysilane, methyldimethoxysilane, and heptamethyltrisiloxane.

2. Modified titanium dioxide, characterized in that, It is obtained by modifying titanium dioxide with a titanium dioxide organic treatment agent, wherein the titanium dioxide organic treatment agent is polyether silane or a titanium dioxide organic treatment agent prepared from polyether silane; The polyether silane is obtained by polymerization of allyl glycidyl ether and siloxane; The siloxane is selected from one or more of trimethoxysilane, methyldimethoxysilane, and heptamethyltrisiloxane.

3. The modified titanium dioxide according to claim 2, characterized in that, The molar ratio of the allyl glycidyl ether to the siloxane is (1~1.5):

1.

4. The modified titanium dioxide according to claim 2 or 3, characterized in that, The preparation method of the polyether silane includes the following steps: Polymerization of allyl glycidyl ether and siloxane in a solvent under a Pt catalyst yields polyether silane.

5. The modified titanium dioxide according to claim 4, characterized in that, The polymerization reaction is carried out at a temperature of 80℃ to 120℃ for a duration of 1 h to 8 h.

6. The modified titanium dioxide according to claim 4, characterized in that, The Pt-containing catalyst is selected from one or more of Speier catalysts and Karstedt catalysts; The solvent is selected from one or more of toluene and tetrahydrofuran.

7. The modified titanium dioxide according to claim 4, characterized in that, The amount of the Pt-containing catalyst is 0.01% to 0.05% of the mass of the siloxane, based on Pt.

8. The modified titanium dioxide according to claim 2 or 3, characterized in that, The titanium dioxide is titanium dioxide coated with zirconium or aluminum.

9. The modified titanium dioxide according to claim 2 or 3, characterized in that, The amount of the titanium dioxide organic treatment agent is 0.3% to 0.8% of the amount of titanium dioxide.

10. A coating containing the modified titanium dioxide as described in any one of claims 2 to 9.

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