A modified organic treating agent, a preparation method thereof and a titanium dioxide modification method

Abstract

The present application relates to titanium white organic modification technical field, the present application provides a kind of preparation method of modified organic treating agent, comprising: alkyl siloxane, alcohol and catalyst are mixed, then drop in deionized water, reaction, namely obtained;The siloxane includes one or several of trimethoxy (methyl) silane, trimethoxy (ethyl) silane, trimethoxy (propyl) silane, isobutyl triethoxysilane, triethoxy (pentyl) silane, n-hexyl triethoxysilane, octyl triethoxysilane, sunflower base triethoxysilane and dodecyl trimethoxysilane.The synthesis method of the present application is simple, titanium white powder modified by alkyl siloxane oligomer has good water resistance, low volatile matter (low water content), good compatibility and flowability in resin.

Description

Technical Field

[0001] This invention relates to the field of organic modification technology for titanium dioxide, and in particular to a modified organic treatment agent, its preparation method, and a method for modifying titanium dioxide. Background Technology

[0002] Although inorganically coated titanium dioxide carries a large number of hydrophilic groups on its surface, its chemical properties are relatively stable, and it inherently possesses a certain degree of water resistance. While it does not easily react chemically with water in a normal aquatic environment, maintaining its structure and properties, its powder dispersibility is poor, and it is prone to agglomeration, affecting its use in downstream applications. However, organically treated titanium dioxide exhibits a significant change in water resistance. An organic protective film forms on its surface, further enhancing its water resistance. This not only better resists the erosion of moisture in the external environment and prevents powder agglomeration but also effectively improves the powder's application performance.

[0003] Plastics are an important application area for titanium dioxide, and therefore have high requirements for the moisture content and water resistance of the powder. Although there are many types of plastics, and the hydrophilicity / hydrophobicity, allowable moisture content, and drying processing temperature of different resins vary greatly, generally speaking, powders with good water resistance are beneficial for plastic processing and molding. However, powders with high moisture content that cannot be removed are prone to causing plastic degradation, bubbles, and poor flowability when used to prepare high-concentration plastic masterbatches, leading to defects such as bubbles and cracks in the finished product, especially for water-sensitive plastics such as polycarbonate.

[0004] From the perspective of improving the hydrophobicity of powders, structures carrying alkyl or aryl groups can provide better water resistance, but for environmental reasons, alkyl types are still the main type. Currently, the organosilicon structures commonly used for the organic modification of titanium dioxide are mainly silicone oil (modified silicone oil) and silane coupling agents. Silicone oil mainly coats the surface of titanium dioxide particles in the form of polymers, reducing the van der Waals forces between particles through the steric repulsion forces generated by the polymer. Although this mode effectively reduces the density of titanium dioxide and changes the optical, magnetic, and electrical properties of the particles, making them more stable in different organic media and improving matrix compatibility, physically adsorbed silicone oil may be adsorbed by other media in harsh environments, thus detaching from the powder surface, leading to changes in powder properties and overflow from the media system. Silane coupling agents, on the other hand, mainly achieve this by having some groups in the coupling agent molecule react with the OH groups on the surface of titanium dioxide particles to form strong chemical bonds, while other groups react chemically or physically with organic polymers, thereby changing the overall properties of titanium dioxide. However, in the plastics field, silane coupling agents can improve compatibility by undergoing a cross-linking reaction with the resin during curing. While this enhances the bonding between the two media, the presence of excessive reactive groups weakens the temperature resistance of the powder. During processing, silane coupling agents are easily decomposed and deteriorated by high temperatures, affecting the pigment properties of titanium dioxide. Considering both organosilicones, the mode of condensing some of the multi-reactive functional groups of the silane coupling agent to form polymer chains not only effectively improves the chemical stability of the powder in the resin but also endows the resin with more superior properties. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a modified organic treatment agent. Titanium dioxide modified by the modified organic treatment agent of the present invention has good water resistance, low volatile matter (low water content), and good compatibility and flowability in resin.

[0006] This invention designs a siloxane oligomer synthesized using alkylsilane coupling agents as raw materials. The reaction does not employ the traditional hydrolysis method, thus preventing the introduction of water. Simultaneously, it reduces the generation of low-boiling-point substances during organic modification and controls the emission of low-volatile substances. This type of treatment agent not only significantly improves the water resistance of titanium dioxide but also effectively enhances the compatibility of the powder.

[0007] This invention uses alkylsiloxanes to oligomerize and obtain functional organosilicon polymers with low viscosity, few chain segments, and high functionality. The water resistance, volatile matter, flowability, and compatibility of the powder coated with this type of treatment agent are tested.

[0008] This invention provides a method for preparing a modified organic treatment agent, comprising:

[0009] Alkylsiloxane, alcohol and catalyst are mixed, and then deionized water is added dropwise to react and obtain the product.

[0010] In some specific embodiments of the present invention, alkylsiloxane, alcohol, catalyst, and magnetic stir bar are first added to a three-necked flask, and both ends are sealed with glass stoppers and rubber stoppers, respectively. The flask is then fixed to a screw, with two-thirds of it immersed in an oil bath. A spherical condenser is inserted into the middle and fixed in place. Water is introduced through a tap, ensuring a moderate water flow. Stirring is started at a moderate speed, and the temperature is set to 60°C.

[0011] After the reaction system temperature stabilizes at 60°C for five minutes, deionized water is drawn into the reaction system using a syringe while removing air bubbles, and then injected slowly through a rubber stopper. Once the addition is complete, the temperature is increased, and the reaction is refluxed. After the reaction is complete and cooled to room temperature, the catalyst and magnetic stir bar are filtered out. Excess ethanol and water are then removed by rotary evaporation in a round-bottom flask to obtain a colorless, transparent liquid product.

[0012] The siloxanes provided by this invention include one or more of trimethoxy(methyl)silane, trimethoxy(ethyl)silane, trimethoxy(propyl)silane, isobutyltriethoxysilane, triethoxy(pentyl)silane, n-hexyltriethoxysilane, octyltriethoxysilane, decanyltriethoxysilane, and dodecyltrimethoxysilane.

[0013] In some specific embodiments of the present invention, the alcohol is preferably a lower fatty alcohol, such as one or more of methanol and ethanol, more preferably ethanol, which not only serves as a reaction solvent, but also undergoes partial alcoholysis exchange reaction with the alkoxy group in alkylsiloxane, which helps to regulate the polarity and reaction rate of the reaction system.

[0014] In the above technical solution, the catalyst is a strong acid macroporous cationic resin with a styrene-divinylbenzene copolymer as the backbone and sulfonic acid groups as the active groups. HD-8 and D001 can be selected. The catalyst dosage is controlled at 0.2%~0.8% of the mass of the raw material siloxane, specifically 0.3%, 0.4%, 0.5%, 0.6%, or 0.7%. This type of catalyst has high catalytic activity and selectivity, effectively promoting the reaction between siloxanes and alcohols. Its macroporous structure facilitates the diffusion of reactants and products, reducing mass transfer resistance. Compared with traditional inorganic acid catalysts, strong acid macroporous cationic resins can be separated and recovered through simple filtration, avoiding equipment corrosion and complex subsequent neutralization and washing processes, reducing production costs, and better aligning with the development trend of green chemistry.

[0015] This catalyst exhibits high catalytic activity and selectivity, effectively promoting the hydrolysis and condensation reactions of alkylsiloxanes. Its macroporous structure facilitates the diffusion of reactants and products, and it is easily separated and recovered from the reaction system, allowing for reuse and reducing production costs and environmental pollution. In some specific embodiments of this invention, the dropping rate of deionized water is controlled at 1-2 drops per second, with a dropping time typically of 30-60 minutes. This avoids excessive reaction of siloxanes due to excessively high local water concentrations, resulting in over-crosslinked products and ensuring a stable reaction. After the dropping is complete, the reaction temperature is raised to 75-85°C, and the reaction is refluxed for 2.5-3 hours. Within this temperature range, the reaction rate is maintained while minimizing side reactions, guiding the reaction towards the formation of the target product. During reflux, the volatile alcohol and water vapor are condensed and refluxed back into the reaction flask using a spherical condenser, improving the utilization rate of the raw materials. The removal of excess ethanol and water by rotary evaporation is typically carried out under vacuum conditions of 0.08-0.095 MPa and a water bath temperature of 40-60°C. Through the rotation and heating of the rotary evaporator, the low-boiling-point ethanol and water are gradually evaporated and condensed for collection, yielding a high-purity, colorless, transparent liquid product—the modified organic treatment agent. This modified organic treatment agent possesses specific molecular structures and properties, enabling its effective application in the modification of titanium dioxide to improve its surface properties and application performance.

[0016] The modified organic treatment agent prepared in this invention is a siloxane oligomer. Siloxane oligomers derived from alkylsilanes avoid the decrease in water resistance of powders caused by the large number of exposed reactive functional groups on silane coupling agents, and also avoid the problems of powder agglomeration and decreased dispersibility caused by silicone oil migration in downstream applications. Alkyl-modified siloxane oligomers have superior compatibility. The functional groups of alkylsiloxane oligomers are not reactive groups; when modifying the surface of titanium dioxide, the polar hydrophilicity of the powder surface will change to non-polar hydrophobicity, thereby improving the compatibility of the powder in hydrophobic resin systems. Furthermore, when the surface of the alkylsiloxane oligomer-modified powder particles is endowed with hydrophobic properties, it is easier to disperse in the matrix resin, easier to be wetted by the substrate, and can also reduce the viscosity of the matrix resin without affecting the processing flowability of the polymer material.

[0017] According to the present invention, the molar ratio of alkylsiloxane: alcohol: deionized water is 1:(1~1.5):(0.5~1.5).

[0018] In some specific embodiments, the molar ratio of alkylsiloxane:alcohol:deionized water can be 1:1:0.5, 1:1.2:1.0, 1:1.5:1.5, etc. By strictly controlling the molar ratio of these three raw materials, the hydrolysis-condensation reaction can be ensured to proceed smoothly, and the molecular weight and structure of the generated linear siloxane oligomers can be effectively controlled. For example, when the proportion of alcohol is in the range of 1 to 1.5, it can provide a suitable solvent environment for the reaction, promote the dissolution and alcoholysis of alkylsiloxanes, and avoid excessive dilution of the reaction system due to excessive alcohol, which would affect the reaction efficiency. When the proportion of deionized water is controlled at 0.5 to 1.5, it can ensure the maximum hydrolysis of hydrolyzable groups in the alkylsiloxane molecule, while preventing excessive water from terminating the reaction, thereby obtaining linear siloxane oligomers with the expected properties, laying a good foundation for the subsequent modification of titanium dioxide.

[0019] This invention provides a modified organic treatment agent, which is prepared by any one of the preparation methods described in the above technical solutions.

[0020] This modified organic treatment agent is mainly composed of siloxane oligomers generated by the hydrolysis and condensation reaction of alkylsiloxanes. Its molecular structure contains a certain amount of active silanol groups and organic alkyl groups. These active groups endow the treatment agent with good reactivity and binding ability to the surface of titanium dioxide. Simultaneously, the organic alkyl groups significantly improve the dispersibility and compatibility of titanium dioxide in organic media. The newly added siloxane polymer chains can not only reduce the van der Waals forces between powder particles through steric hindrance but also selectively alter the surface properties of the particles, meeting a wider range of application requirements. The modified organic treatment agent obtained through the above specific preparation method features uniform molecular weight distribution and controllable active group content, allowing for targeted adjustments based on the specific application requirements of different titanium dioxide products, providing a reliable material basis for achieving efficient modification of titanium dioxide.

[0021] This invention provides a method for modifying titanium dioxide, comprising:

[0022] The inorganically coated titanium dioxide is dried, pulverized, mixed with a modified organic treatment agent, and then subjected to organic treatment to obtain the final product.

[0023] Titanium dioxide powder that has undergone inorganic coating but no organic treatment is dried in an oven at 110-120℃, and the dried powder is then crushed. The mesh size of the crushed powder is 500-800.

[0024] An organic treatment agent is added to the crushed powder, and the mixture is homogenized using a crusher; then, organic treatment is carried out. After treatment, the collected powder is subjected to air-powder processing.

[0025] The inorganic-coated titanium dioxide described in this invention, which has not undergone organic treatment, is a single-aluminum coated titanium dioxide, particularly preferably a single-aluminum coated titanium dioxide produced by the chloride or sulfuric acid process. Commercially available products are acceptable, and this invention does not limit the choice. The embodiments of this invention use commercially available single-aluminum coated titanium dioxide produced by the chloride process.

[0026] The organic treatment described in this invention is performed at a temperature of 55-65°C for 2-5 minutes.

[0027] The modified organic treatment agent described above is prepared by the preparation method described in the above technical solution or is a modified organic treatment agent described in the above technical solution.

[0028] In some specific embodiments of the present invention, the amount of the modified organic treatment agent added is 0.6 wt% to 1.5 wt% of the amount of titanium dioxide added; specifically, it can be 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, etc. For example, when the application scenario of titanium dioxide requires high dispersibility, an addition amount of 1.2 wt% to 1.5 wt% can be selected to ensure that the organic treatment agent can fully coat the surface of titanium dioxide particles and effectively improve its dispersion stability in organic media; while for some scenarios with stricter cost control or higher requirements for other properties of titanium dioxide (such as whiteness), an addition amount of 0.6 wt% to 0.9 wt% can be used to reduce production costs while ensuring the basic modification effect. By reasonably controlling the addition amount of the modified organic treatment agent, the optimal allocation of resources and effective cost control can be achieved while meeting the different application performance requirements of titanium dioxide.

[0029] Silicone oil migration from modified powder surfaces: This refers to the phenomenon of silicone oil precipitating, migrating, or seeping from the powder surface after surface modification of titanium dioxide during subsequent application or storage. If the silicone oil is not sufficiently chemically bonded and is only physically coated, it is more likely to migrate during long-term use. Silane coupling agents can enhance the chemical bond between silane and powder, reducing migration caused by physical adsorption.

[0030] Disadvantages of using silane coupling agents: Although titanium dioxide has hydroxyl groups on its surface, the powder modification process is relatively fast, resulting in poor modification effects. Further pretreatment of the silane coupling agent is necessary to improve its modification efficiency. Most silane coupling agents are not heat-resistant, and their use in titanium dioxide, especially in the plastics industry, easily causes yellowing. From the perspective of the powder's own moisture resistance, the numerous silanol groups on the silane coupling agent monomer are exposed on the powder surface, easily combining with water in the environment, leading to instability of the organic layer and a decline in powder performance. Alkylsiloxane oligomers, compared to the original monomers, have fewer reactive silanol groups while also possessing polymer segments. This can overcome the problem of incomplete surface coating and poor dispersibility of the inorganic layer of titanium dioxide caused by excessively short organic segments.

[0031] This invention provides a method for preparing a modified organic treatment agent, comprising: mixing an alkylsiloxane, an alcohol, and a catalyst, then adding deionized water dropwise, and reacting to obtain the product; wherein the siloxane includes one or more of trimethoxy(methyl)silane, trimethoxy(ethyl)silane, trimethoxy(propyl)silane, isobutyltriethoxysilane, triethoxy(pentyl)silane, n-hexyltriethoxysilane, octyltriethoxysilane, decanyltriethoxysilane, and dodecyltrimethoxysilane. The synthesis method of this invention is simple, and titanium dioxide modified with alkylsiloxane oligomers exhibits excellent water resistance, low volatile matter (low water content), and good compatibility and flowability in resins. Detailed Implementation

[0032] This invention provides a modified organic treatment agent and its preparation method, as well as a method for modifying titanium dioxide. 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 fall within the scope of protection of this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly 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.

[0033] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0034] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0035] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0036] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0037] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0038] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0039] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0040] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0041] The embodiments and comparative examples of this invention describe some examples, in which the embodiments illustrate certain implementations of the invention. However, this does not mean that the effects of the invention can only be achieved in these examples.

[0042] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a modified organic treatment agent and its preparation method, and a titanium dioxide modification method provided by the present invention.

[0043] Technical solution for testing the water resistance of titanium dioxide: The contact angle between water and a titanium dioxide plane is tested using a contact angle tester. A titanium dioxide powder plane is prepared using a tablet press, placed on the tester platform, and after adjusting its test interface, water is dripped onto the plane. Once the droplet contacts and stabilizes with the titanium dioxide plane, the angle is recorded.

[0044] In the above technical solution, the liquid drop rate is 2 microliters per second.

[0045] Technical solution for testing the volatility of titanium dioxide: Weigh 50 grams of powder into a crucible and place it in an oven. Record the weight change over 4 hours at 105℃. Test three parallel samples and take the average value. Volatile matter % = (Powder weight before test - Powder weight after test) / Powder weight before test.

[0046] Technical solution for testing the compatibility and flowability of titanium dioxide: Titanium dioxide and resin are mixed uniformly, and their compatibility (torque) is tested using a twin-screw extruder. Extruded and sheared plastic particles are then subjected to a melt flow index tester, heated and sheared, and the flowability (melt flow index) of the titanium dioxide is assessed based on the average mass of the sheared segment.

[0047] In the above technical solution, the ratio of titanium dioxide to resin can be from 100:1 to 100:15, preferably 100:5, and the resin can be PP or ABS.

[0048] Example 1

[0049] The molar ratio of propylsiloxane:alcohol:deionized water was 1:1:1. 20 g of trimethoxy(propyl)silane, 3.84 g of methanol, 0.08 g of HD-8 catalyst, and a magnetic stir bar were added to a three-necked flask. The flask was sealed with a glass stopper and a rubber stopper at each end, and fixed to a screw. Two-thirds of the flask was immersed in an oil bath. A spherical condenser was inserted into the center and secured. Water was introduced through a tap, ensuring a moderate flow. Stirring was started at a moderate speed, and the temperature was raised to 60°C. After the reaction system temperature stabilized at 60°C for five minutes, 2.16 g of deionized water was injected into the reaction system using a syringe, removing air bubbles, and then slowly added dropwise through the rubber stopper. After the addition was complete, the temperature was raised to 80°C, and the reaction was refluxed for three hours. After the reaction was complete and cooled to room temperature, the catalyst and magnetic stir bar were filtered off. Excess alcohol and water were removed by rotary evaporation in a round-bottom flask, yielding a colorless, transparent liquid product #1 (90% yield).

[0050] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of organic treatment agent #1 were added to the crushed powder, and the mixture was stirred using a crusher and then subjected to organic treatment at 60°C. After treatment, the collected powder was subjected to air-powder processing to obtain powder A from Example 1.

[0051] Example 2

[0052] Octylsiloxane:alcohol:deionized water in a molar ratio of 1:1.2:1.5 was used. 20 g of octyltriethoxysilane, 3.86 g of ethanol, 0.08 g of HD-8 catalyst, and a magnetic stir bar were added to a three-necked flask. The flask was sealed with a glass stopper and a rubber stopper at each end, and fixed to a screw. Two-thirds of the flask was immersed in an oil bath. A spherical condenser was inserted into the center and secured. Water was introduced through a tap, ensuring a moderate flow. Stirring was started at a moderate speed, and the temperature was raised to 60°C. After the reaction system temperature stabilized at 60°C for five minutes, 1.89 g of deionized water was injected into the reaction system using a syringe, removing air bubbles, and then slowly added dropwise through the rubber stopper. After the addition was complete, the temperature was raised to 80°C, and the reaction was refluxed for three hours. After the reaction was complete and cooled to room temperature, the catalyst and magnetic stir bar were filtered off. Excess alcohol and water were removed by rotary evaporation in a round-bottom flask, yielding a colorless, transparent liquid product #2, with a yield of 83%.

[0053] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of organic treatment agent #2 were added to the crushed powder, and the mixture was stirred using a crusher. Organic treatment was then performed at 60°C. After treatment, the collected powder was subjected to steam treatment to obtain powder B from Example 1.

[0054] Example 3

[0055] The molar ratio of decylsiloxane:alcohol:deionized water was 1:1.3:1.2. 20 g of decyltriethoxysilane, 3.95 g of methanol, 0.08 g of HD-8 catalyst, and a magnetic stir bar were added to a three-necked flask. The flask was sealed with a glass stopper and a rubber stopper at each end, and fixed to a screw. Two-thirds of the flask was immersed in an oil bath. A spherical condenser was inserted into the center and secured. Water was introduced through a tap, ensuring a moderate flow. Stirring was started at a moderate speed, and the temperature was raised to 60°C. After the reaction system temperature stabilized at 60°C for five minutes, 1.42 g of deionized water was injected into the reaction system using a syringe, removing air bubbles, and then slowly added dropwise through the rubber stopper. After the addition was complete, the temperature was raised to 80°C, and the reaction was refluxed for three hours. After the reaction was complete and cooled to room temperature, the catalyst and magnetic stir bar were filtered off. Excess alcohol and water were removed by rotary evaporation in a round-bottom flask, yielding a colorless, transparent liquid product #3, with a yield of 76%.

[0056] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of organic treatment agent #3 were added to the crushed powder, and the mixture was stirred using a crusher. Organic treatment was then performed at 60°C. After treatment, the collected powder was subjected to air-powder processing to obtain powder C from Example 1.

[0057] Example 4

[0058] The molar ratio of dodecylsiloxane:alcohol:deionized water was 1:1.1:1. 20 g of dodecyltrimethoxysilane, 3.04 g of methanol, 0.08 g of HD-8 catalyst, and a magnetic stir bar were added to a three-necked flask. The flask was sealed with a glass stopper and a rubber stopper at both ends, and fixed to a screw. Two-thirds of the flask was immersed in an oil bath. A spherical condenser was inserted into the center and secured. Water was introduced through a tap, ensuring a moderate flow. Stirring was started at a moderate speed, and the temperature was raised to 60°C. After the reaction system temperature stabilized at 60°C for five minutes, 1.08 g of deionized water was slowly added dropwise through the rubber stopper using a syringe, removing air bubbles. After the addition was complete, the temperature was raised to 80°C, and the reaction was refluxed for three hours. After the reaction was complete and cooled to room temperature, the catalyst and magnetic stir bar were filtered off. Excess alcohol and water were removed by rotary evaporation in a round-bottom flask, yielding a colorless, transparent liquid product #4, with a yield of 74%.

[0059] Titanium dioxide powder with inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of organic treatment agent #4 were added to the crushed powder, and the mixture was stirred using a crusher and then subjected to organic treatment at 60°C. After treatment, the collected powder was subjected to air-powder processing to obtain powder D in Example D.

[0060] Table 1

[0061]

[0062] As shown in Table 1, the contact angles of the powders coated with different types of treatment agents are all greater than 150°, indicating that these polymers can all achieve superhydrophobic surfaces. Simultaneously, the volatile matter content of the powders is the same and below 0.5%, indicating that the powders are waterproof with low bound water content and exhibit uniform and dense coating. The low filtration pressure value reflects good dispersibility of the powders in plastics. Adding a small amount of powder to the plastics enhances the flowability of the plastics (melt index of pure PP is 7.3 g / 10 min, and ABS is 22.6 g / 10 min). These long-chain siloxane oligomers can effectively improve the properties of the powders and in plastics, providing new ideas and directions for further optimization of subsequent product performance.

[0063] Comparative Example 1

[0064] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of methyltrimethoxysiloxane organic treatment agent was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60°C. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder E.

[0065] Comparative Example 2

[0066] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of propyltrimethoxysiloxane organic treatment agent was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60°C. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder F.

[0067] Comparative Example 3

[0068] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of octyltriethoxysiloxane organic treatment agent was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60°C. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder G.

[0069] Comparative Example 4

[0070] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120°C. 150 grams of the dried powder was then crushed. 0.9 grams of dodecyltrimethoxysiloxane organic treatment agent was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60°C. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder H.

[0071] Comparative Example 5

[0072] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120℃. 150 grams of the dried powder was then crushed. 0.9 grams of polysiloxane organic treatment agent A (purchased modified silicone oil) was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60℃. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder I.

[0073] Comparative Example 6

[0074] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120℃. 150 grams of the dried powder was then crushed. 0.9 grams of polysiloxane organic treatment agent B (purchased modified silicone oil) was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60℃. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder J.

[0075] Comparative Example 7

[0076] Titanium dioxide powder that has undergone inorganic coating but no organic treatment was dried in an oven at 120℃. 150 grams of the dried powder was then crushed. 0.9 grams of polysiloxane organic treatment agent C (purchased modified silicone oil) was added to the crushed powder, and the mixture was homogenized using a crusher. Organic treatment was then performed at 60℃. After treatment, the collected powder was subjected to steam treatment to obtain comparative powder K.

[0077] Table 2

[0078]

[0079] As shown in Table 2, comparing alkylsilane coupling agents and modified polysiloxanes, alkylsilane-derived siloxane oligomers avoid the decrease in powder water resistance caused by the large number of exposed reactive functional groups on silane coupling agents. They also avoid the problems of silicone oil migration in downstream applications, which leads to powder agglomeration and decreased dispersibility. Alkyl-modified siloxane oligomers exhibit superior compatibility. Since the functional groups of alkylsiloxane oligomers are not reactive, when modifying the surface of titanium dioxide, the polar hydrophilicity of the powder surface changes to non-polar hydrophobicity, thereby improving the compatibility of the powder in hydrophobic resin systems. Furthermore, when the surface of the alkylsiloxane oligomer-modified powder particles is endowed with hydrophobic properties, it is easier to disperse in the matrix resin, more easily wetted by the substrate, and can also reduce the viscosity of the matrix resin without affecting the processing flowability of the polymer material.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a modified organic treatment agent, characterized in that, include: Alkylsiloxane, alcohol and catalyst are mixed, and then deionized water is added dropwise. The reaction proceeds to obtain the product. The siloxanes include one or more of trimethoxy(methyl)silane, trimethoxy(ethyl)silane, trimethoxy(propyl)silane, isobutyltriethoxysilane, triethoxy(pentyl)silane, n-hexyltriethoxysilane, octyltriethoxysilane, decanyltriethoxysilane, and dodecyltrimethoxysilane.

2. The preparation method according to claim 1, characterized in that, The catalyst comprises a strong acid macroporous cationic resin with a styrene-divinylbenzene copolymer as the backbone and sulfonic acid groups as active groups; preferably HD-8 or D001.

3. The preparation method according to claim 2, characterized in that, The catalyst is used in an amount of 0.2wt% to 0.8wt% of alkylsiloxane.

4. The preparation method according to claim 1, characterized in that, The alcohol is methanol or ethanol.

5. The preparation method according to claim 1, characterized in that, The molar ratio of the alkylsiloxane: alcohol: deionized water is 1:(1~1.5):(0.5~1.5).

6. The preparation method according to claim 1, characterized in that, Add deionized water dropwise at 60℃. After the addition is complete, raise the temperature to 75~85℃ and reflux for 2.5~3 hours.

7. A modified organic treatment agent, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. A method for modifying titanium dioxide, characterized in that, include: The inorganically coated titanium dioxide is dried, pulverized, mixed with a modified organic treatment agent, and then subjected to organic treatment to obtain the product. The modified organic treatment agent is prepared by the preparation method according to any one of claims 1 to 6 or the modified organic treatment agent according to claim 7.

9. The method according to claim 8, characterized in that, The amount of the modified organic treatment agent added is 0.6 wt% to 1.5 wt% of the amount of titanium dioxide added.

10. The method according to claim 8, characterized in that, The drying temperature is 110~120℃; the pulverization mesh size is 500-800; the organic treatment temperature is 55~65℃, and the time is 2-5 minutes.

Images