CN111067812A - Talc-loaded nano TiO2Composite uvioresistant agent and its prepn process - Google Patents

Abstract

The invention relates to a talc loaded nano TiO₂A composite uvioresistant agent and a preparation technology thereof are disclosed, wherein natural flaky mineral talc is used as a carrier mineral raw material, a hydrothermal method is adopted, and step 1, a titanium sulfate solution of 0.3-1.2 mol/l is prepared and uniformly stirred; 2, weighing urea according to the molar ratio of 1-3: 1 of urea to titanium sulfate, adding the urea to a titanium sulfate solution, uniformly mixing and stirring, and adding a proper amount of talc to enable TiO in a mixed system to be TiO₂The mass ratio of the titanium sulfate to the talc is 0.5-2, and the titanium sulfate, the urea and the talc are uniformly stirred to obtain a titanium sulfate-urea-talc mixed solution; performing hydrothermal reaction, pouring the mixed solution into a polytetrafluoroethylene reaction kettle, and reacting at the temperature of 140-200 ℃ for 2-8 h; 4, removing impurities in the mixed liquid by centrifugal washing; drying the materials at 105 ℃ for 4-6 h to obtain the talcLoaded nano TiO₂And (3) a composite anti-ultraviolet agent. The method has the advantages of obvious effect, good safety, simple process, easy popularization and application, wide application and remarkable social and economic benefits.

Description

Talc-loaded nano TiO2Composite uvioresistant agent and its prepn process

1. Field of the invention

The invention relates to a talc loaded nano TiO₂Composite uvioresistant agent and its prepn process, hydrothermal process of making nanometer TiO material₂Coating the surface of the natural flaky mineral talc to obtain talc-loaded nano TiO₂The composite uvioresistant agent is suitable for the field of uvioresistant materials or ultraviolet shielding materials.

2. Background of the invention

2.1 ultraviolet concept

Ultraviolet (UV) is an electromagnetic wave having a wavelength of 200nm to 400 nm. The ultraviolet rays in the sunlight can be divided into three sections of long-wave ultraviolet ray UVA (320-400 nm), medium-wave ultraviolet ray UVB (280-320 nm) and short-wave ultraviolet ray UVC (200-280 nm) according to the wavelength. Proper sunlight irradiation can increase oxygen content of organism cells, reduce blood sugar and cholesterol content, and enhance human vitality. However, when the sun is excessively exposed for a long time, various skin diseases such as sunburn, freckle, acne and the like are easily induced and aggravated, and internal organs of the body are damaged in severe cases. The basic characteristics of the uv segments are now collated as shown in table 1.

TABLE 1 classification and characterization of UV

The short wave ultraviolet UVC is absorbed by the ozone layer, cannot reach the ground and has no effect on human bodies. Long-wave ultraviolet UVA causes photoaging of the skin, resulting in skin cancer. The energy of the medium-wave ultraviolet UVB is highest, and the great part of the energy is absorbed by the skin dermis to cause the dermal blood vessels to expand and present the symptoms of red swelling, blisters and the like. Most skin damage is caused by UVB, which if exposed to UVB for a long time, causes erythema, inflammation, skin aging, and severe skin cancer.

Ultraviolet rays not only cause harm to human bodies, but also have certain damage and aging effects on coatings, plastics, printing ink and other high polymer materials, so that the high polymer materials have the phenomena of light loss, fading, yellowing, cracking, peeling, embrittlement, pulverization, strength reduction, delamination and the like. Even indoor light and sunlight transmitted through a glass window can degrade some materials.

Therefore, ultraviolet rays have considerable harm to human health, high polymer materials and the like, so that the research and application of the ultraviolet resistant agent or the ultraviolet shielding material have very important practical significance.

2.2 research and State of the Art ultraviolet Shielding materials

Since the discovery of the hazards of ultraviolet light by humans, some means have been taken to shield ultraviolet light. Ultraviolet shielding materials for human skin protection are mainly of two types: one category is ultraviolet resistant textiles including sun protection clothing, sun protection hats, sun protection gloves, and sun protection umbrellas, among others. The ultraviolet resistant coating is a sunscreen skin care product or a cosmetic mainly used in daily life, and is prepared into a paste or liquid semi-liquid product by mutually matching ultraviolet resistant sunscreens (organic or inorganic) or compounding the ultraviolet resistant sunscreens with other components. The ultraviolet shielding material for protecting the high polymer material is mainly a filler with an ultraviolet shielding function, but the research on the aspect is relatively weak.

The anti-ultraviolet agent in skin care products or cosmetics means a substance which can effectively absorb or scatter solar radiation, can reduce damage to the skin, and can effectively absorb or scatter long-wave ultraviolet rays (UVA) and medium-wave ultraviolet rays (UVB) in sunlight. They can be divided into physical and chemical sunscreens by their protective mechanism of action, also commonly referred to as inorganic and organic sunscreens, respectively.

Chemical sunscreens (organic sunscreens), also known as uv absorbers, are primarily organic compounds which absorb harmful uv radiation. Among them, tert-butyl methoxydibenzoylmethane is the most representative UVA segment ultraviolet absorbent in the current sunscreen cosmetics, and isooctyl methoxycinnamate is the most widely used UVB segment ultraviolet absorbent in the current sunscreen cosmetics. However, organic sunscreens often require strict precautions in terms of heat resistance, stability, ultraviolet absorption range, toxicity, etc., which act only in a single wavelength band (UVA or UVB), and which may decompose and lose the sunscreen effect under the action of light, with a short period of effectiveness. In contrast, inorganic sunscreens (physical sunscreens) are more stable and safer, and they achieve the goal of sunscreening by primarily scattering ultraviolet light while absorbing ultraviolet light in small amounts. Inorganic sunscreens are increasingly widely used due to their advantages of high efficiency, safety, durability, etc.

Current inorganic sunscreens (physical sunscreens) are predominantly TiO₂And ZnO, theyAre all semiconductor materials, TiO₂Mainly aiming at UVB protection, ZnO mainly shields UVA. But the sun-screening and ultraviolet screening effects of the two are closely related to the particle size or nanometer effect of the two. The results of the previous study show that when both are nanoparticles, i.e. TiO₂When the particle size is 30-50 nm (grandma et al, 1998) and the particle size of ZnO is 10-35 nm, the nano effect is prominent, and the sunscreen ultraviolet shielding effect is excellent (YaoOer et al, 2003).

Nano TiO 2₂As a widely used physical sun-screening agent, the principle of shielding ultraviolet rays is to absorb and scatter the ultraviolet rays, and the sun-screening agent has the characteristics of small particle size, large specific surface area, good stability, small irritation and the like; in addition to good ultraviolet shielding performance, the antibacterial ultraviolet shielding material also has the advantages of safety, stability, heat resistance, certain antibacterial property and the like, so the antibacterial ultraviolet shielding material is widely applied to the field of sunscreen skin care products or cosmetics in recent years.

However, due to the nano TiO₂The nano-particles have the characteristics of weak polarity, tiny nano-particles and high surface energy, and are in a thermodynamic unstable state and tend to agglomerate, so that the exertion of the nano-effect and the ultraviolet shielding effect is limited. And, in the skin care product or cosmetic manufacturing process, the nano TiO₂The particles are difficult to disperse to the original particle size, the ultraviolet absorption effect in UVA, UVB, and UVC bands is reduced, the transparency and ultraviolet shielding performance thereof cannot be sufficiently exhibited, and the effect as a sunscreen agent in practical use is not good. In summary, nano TiO₂As an inorganic sunscreen, there are the following major problems:

(1) agglomeration problem: nano TiO 2₂The surface energy of (a) is high and the particles tend to agglomerate.

(2) The problem of delamination: the density of the emulsifier in the sunscreen product is about 0.96-1.1g/cm³And nano TiO₂Has a density of about 3.8 to 4.3g/cm³So that the nano TiO with high density is used₂When the emulsifier is added, the precipitation is easy to occur, and the layering phenomenon is generated. This delamination phenomenon greatly limits the nano-TiO₂The using efficiency of the material can not be directly mixed with common cosmetics for use. If used aloneIt also causes delamination with the dispersion and must be shaken well before use. This not only causes inconvenience to the user but also increases the use cost.

(3) Health problems are as follows: nano TiO in sunscreen products₂The sweat easily gathers at the human skin horny layer, the hair follicle sebaceous gland opening and the wrinkle, and the size of the human facial pores is generally 20 mu m, so the sweat is not easy to be secreted, and the skin infection is easily caused.

(4) The aesthetic problem is that: due to the nanometer TiO₂The agglomeration of the ingredients may cause unnatural whitening when applied to the skin, which may affect the aesthetic appearance.

(5) The price problem is as follows: due to the nanometer TiO₂Can not be directly mixed with common cosmetics for use, and in order to overcome the layering phenomenon of dispersion liquid when used alone, a small-sized special container and a device are needed in actual use, so that the production and use costs of physical sunscreen products are greatly increased, the market price of the products is generally higher, and the using amount of the products is limited.

2.3 nanometer TiO₂State of the art of preparation

According to the state of the raw materials and different preparation processes, the nano TiO₂The preparation method mainly comprises three types of liquid phase method, solid phase method and gas phase method. Among them, the gas phase method is not suitable for wide application due to the disadvantages of harsh reaction conditions, high production cost, low product purity, etc. Currently preparing nano TiO₂The liquid phase method and the solid phase method are mainly adopted, and the advantages and disadvantages are shown in Table 2.

TABLE 2 Nano TiO₂Advantages and disadvantages of the principal preparation method

2.4 mineral-loaded nano TiO₂Current state of the art for the study of composite anti-UV agents

Solves the problem of nano TiO₂The problems of agglomeration, delamination and the like can be started from two aspects: firstly, a certain preparation method is adopted to prepare nano TiO₂Modifying to obtain nanometer TiO₂Regulating and controlling the appearance and the like; firstly, the mineral is used as a carrier to load the nano TiO₂. The leading research progress of the predecessors was as follows:

CN 107604644A discloses a hydrothermal method for preparing illite-loaded nano TiO₂The method of compounding ultraviolet screening agent features that in hydrothermal system of titanium sulfate and ammonia water, nanometer level TiO is realized₂The dispersion and the combination on the surface of the illite are sufficient. The composite powder has good ultraviolet shielding performance, and can be widely applied to the protection fields of textile finishing, paint and the like.

CN 107012728A discloses a sunscreen agent loaded with nano titanium dioxide prepared by taking kaolinite, polyethylene glycol and nano titanium dioxide as raw materials and adopting a mechanochemical method, the preparation process has no waste water, the process equipment is simple, the operation is simple and convenient, and the sunscreen and anti-aging performance of decorative paper can be improved by using the sunscreen agent in the production of decorative paper.

CN 103773085A discloses a functional mica pigment processing technique, which takes sericite as raw material, tetravalent titanium salt as titanium source to coat a mica substrate, zinc sulfate solution is selected to be added into the coated TiO₂Adding calcium hydroxide while stirring to coat TiO₂Filtering, washing, drying and calcining the sericite slurry. The functional mica has better glossiness, can insulate heat and has excellent ultraviolet shielding performance.

Shenhongling, Zhengshuirin, etc. (2009) mentioned the use of hydrolytic precipitation method to coat nano TiO on the surface of calcined kaolin₂Preparation of TiO₂The calcined kaolin composite powder material has good uvioresistant performance under the proper preparation conditions, namely, when the coating amount is 9 percent, the dosage of hydrochloric acid is 0.05ml/g, and the dosage of ammonium sulfate is 1.75 ml/g.

From the above description, it can be seen that the mineral loaded nano TiO is currently concerned₂The preparation method of the anti-ultraviolet agent is mainly a liquid phase method, wherein Jianjiang and the like (2018) adopt a hydrothermal method to prepare nano TiO₂The illite composite powder material. However, according to the search of the inventor, the hydrothermal method for preparing the talc-supported nano TiO has not been adopted at present₂Composite uvioresistant agentThe technical results of (1) are reported.

3. Technical scheme

The invention aims to load nano TiO by using natural flaky mineral talc with a layered structure as a raw material₂Preparing a composite uvioresistant agent or ultraviolet shielding material to overcome the defects of the existing nano TiO₂Easy agglomeration, easy delamination, poor dispersibility and the like, improves the sun-screening and ultraviolet-screening performances, improves the beautiful effect, prevents the whitening phenomenon, improves the use efficiency and reduces the use cost. To achieve the above object, the following technical problems must be solved:

(1) selection of carrier mineral raw materials: the layered structure silicate minerals are of various types, and the selection conditions are as follows: the mineral crystal has a layered structure and two-dimensional habit crystals, is mainly in a fine scaly shape, is non-toxic and harmless, and is rich in mineral raw materials.

(2) Nano TiO 2₂Selection of a preparation method: as shown in Table 2, several methods of the present invention have advantages and disadvantages, and the selection conditions of the preparation method of the present invention are: no toxicity and harm, convenience and feasibility and good effect.

(3) Nano TiO 2₂The hydrothermal method preparation process comprises the following steps: on the basis of the work in the step (2), the hydrothermal method for preparing the nano TiO is further determined by experiments₂The process conditions of (1).

(4) Talc-loaded nano TiO₂The preparation process of the composite uvioresistant agent comprises the following steps: on the basis of the work in the step (3), the hydrothermal method is further experimentally determined to prepare the talc-loaded nano TiO₂The technological conditions of the composite uvioresistant agent.

The specific technical scheme is as follows:

3.1 selection of Carrier mineral raw materials

Talc is a magnesium silicate mineral with 2:1 type trioctahedral lamellar structure, and has crystal chemical formula of Mg₃[Si₄O₁₀](OH)₂The theoretical chemical composition is MgO 31.72%, SiO₂63.52% and H₂And 4.76 percent of oxygen. Talc is monoclinic system, and its crystal structure is composed of two layers of SiO₄]Tetrahedron and a layer of [ MgO₆]Octahedron structure with typical 2:1 layer structure; gloss of glassHas slippery feel, no toxicity and harm and stable chemical property, and meets the requirement of being used as nano TiO₂The requirement of carrier minerals.

FIG. 1 is an X-ray powder diffraction pattern (XRD) of a talc sample used in the present invention, and it can be seen that the diffraction peak of the talc is relatively sharp, which indicates that the raw material talc has a complete crystal structure and a good crystalline state, and is substantially consistent with talc standard card (PDF: 29-1493), and the characteristic peaks are:

from the XRD spectrum, the sample contained a small amount of chlorite.

Table 3 shows the results of X-ray fluorescence spectrum (XRF) measurements of the chemical components of the talc sample used in the present invention, and it can be seen that the weight percentage (%) of the chemical components of the talc sample is closer to the theoretical components, and the contents of other impurities are very low, and the talc sample does not contain toxic and harmful impurities to human body. And the XRD analysis result is combined, so that the experimental sample is relatively pure, belongs to the talc single mineral aggregate and meets the selection condition of the carrier mineral raw material.

TABLE 3X-ray fluorescence Spectroscopy (XRF) measurements of the chemical composition of talc samples (in weight percent,%)

Name (R)	SiO2	Al2O3	Fe2O3	TiO2	CaO	MgO	K2O	Na2O	MnO	P2O5	SO3	H2O
													Content (wt.)	56.70	3.89	1.85	0.26	2.45	30.33	0.01	0.04	0.02	0.11	0.01	4.33

3.2 nanometer TiO₂Selection of preparation methods

According to related documents, by comparing the advantages and the disadvantages of the five methods in table 2, the hydrothermal method can directly obtain powder with good crystallinity in one step, high-temperature roasting crystallization is not needed, secondary growth of crystal grains is avoided, and hard agglomeration is formed, so that the hydrothermal method is adopted for preparation, and an ultraviolet-visible spectrophotometer is adopted for detection and analysis of the ultraviolet shielding performance, and the result is shown in fig. 2.

According to the purpose and requirement of the invention, the ultraviolet resistant agent or the ultraviolet shielding material not only ensures higher absorbance of the ultraviolet region, but also ensures high transmittance of the visible region. As can be seen from FIG. 2, industrial TiO₂Although the paint also has certain ultraviolet resistance, the ultraviolet shielding performance is far inferior to that of nano TiO₂. The standard for distinguishing the ultraviolet resistance of domestic products at present is divided into the following parts according to the ultraviolet shielding rate: class a, the ultraviolet shielding rate is more than 90 percent; b level, ultraviolet shielding rate is 80-90%; c level, and the ultraviolet shielding rate is 50-80%. The ultraviolet resistant agent or ultraviolet shielding material should be selected from a class a as appropriate. As shown in FIG. 2, the ultraviolet shielding rate of industrial titanium dioxide just reaches 90%, belongs to b-grade and cannot meet the requirement of an ultraviolet shielding material, and the nano TiO prepared by a hydrothermal method₂The ultraviolet shielding rate of the composite material is more than 90 percent, belongs to a grade a, and meets the requirement of the invention.

3.3 nanometer TiO₂Hydrothermal preparation process

The invention further determines the hydrothermal method to prepare the nano TiO through experiments₂The process conditions are as follows:

(1) preparing a titanium sulfate solution: selecting titanium sulfate (Ti (SO)₄)₂) Preparing titanium sulfate into 0.3-1.2 mol/l titanium sulfate solution as a titanium source, and magnetically stirring for 30min to fully dissolve the titanium sulfate solution;

(2) preparing a titanium sulfate-urea mixed solution: adding a certain amount of urea into a titanium sulfate solution to ensure that the amount ratio of the urea to the titanium sulfate is 1-3: 1, and fully stirring for 1-2 h;

(3) hydrothermal reaction: pouring the titanium sulfate-urea mixed solution into a polytetrafluoroethylene reaction kettle (the solution accounts for 70-80% of the volume of the kettle), placing the sealed hydrothermal kettle at the hydrothermal temperature of 140-200 ℃ for full reaction for 2-8 h, and after the reaction is finished, naturally cooling, pouring out supernatant in the reaction kettle to obtain a kettle bottom reaction product;

(4) washing to remove impurities: carrying out centrifugal washing on the reaction product by adopting a centrifugal washing device, washing by using distilled water twice, and washing by using absolute ethyl alcohol twice to remove impurities;

(5) drying the materials: transferring the reaction product after washing and impurity removal into a drying device, wherein the drying temperature is 105 ℃, and the drying time is 4-6 h, thus obtaining the nano TiO₂And (3) powder.

FIG. 3 shows the hydrothermal preparation of nano TiO₂The X-ray powder crystal diffraction spectrum shows that three standard strong peaks with sharp peak shapes and high intensity appear in the range of 20-50 DEG diffraction angle, namely

This is in conjunction with nano TiO₂The standard PDF cards (21-1272) are substantially coincident. Considering that the characteristic peaks appearing in the whole angle diffraction range are relatively sharp, the nano TiO is shown₂The crystal form of the sample is better, and the crystallization is more complete. Meanwhile, no miscellaneous peak which can not correspond to the standard card appears in the diffraction pattern, which indicates that the purity of the sample is higher.

FIG. 4 shows the hydrothermal preparation of nano TiO₂The analysis photo of the scanning electron microscope shows that the nano TiO is₂The powder crystal grains are spherical or quasi-spherical and have the characteristics of nano particles, the particle size is 30-50 nm, but the obvious agglomeration phenomenon occurs.

3.4 Talc-loaded Nano TiO₂Preparation process of composite uvioresistant agent

On the basis of the work, the hydrothermal method is further experimentally determined to prepare the talc-loaded nano TiO₂The process conditions of the composite uvioresistant agent are as follows:

(1) preparing a titanium sulfate solution: selecting titanium sulfate (Ti (SO)₄)₂) Preparing titanium sulfate into 0.3-1.2 mol/l titanium sulfate solution as a titanium source, and magnetically stirring for 30min to fully dissolve the titanium sulfate solution;

(2) preparing a titanium sulfate-urea-talc mixed solution: adding a certain amount of urea into the titanium sulfate solution to ensure that the amount ratio of the urea to the titanium sulfate is 1-3: 1, fully stirring for 1-2 h,adding a proper amount of talc to ensure that TiO in the mixed system₂The mass ratio of the talc to the talc is 0.5-2, the mixture is fully stirred for 1-2 hours, and ultrasonic oscillation is carried out for 30 min;

(3) hydrothermal reaction: pouring the titanium sulfate-urea-talc mixed solution into a polytetrafluoroethylene reaction kettle (the solution accounts for 70-80% of the kettle volume), placing the sealed hydrothermal kettle at the hydrothermal temperature of 140-200 ℃ for full reaction for 2-8 h, and after the reaction is finished, naturally cooling, pouring out supernatant in the reaction kettle to obtain a kettle bottom reaction product;

(4) washing to remove impurities: carrying out centrifugal washing on the reaction product by adopting a centrifugal washing device, washing by using distilled water twice, and washing by using absolute ethyl alcohol twice to remove impurities;

(5) drying the materials: transferring the reaction product after washing and impurity removal into a drying device, wherein the drying temperature is 105 ℃, and the drying time is 4-6 h, thus obtaining the talc-loaded nano TiO₂And (3) a composite anti-ultraviolet agent.

4. Technical advantages

(1) The effect is obvious. The invention takes talcum as a carrier and adopts a hydrothermal method to prepare the talcum-loaded nano TiO₂The composite uvioresistant agent and the composite material thereof also have better uvioresistant performance or ultraviolet shielding performance, better dispersibility in solvent and higher transmittance to visible light, thereby solving the problem of nano TiO₂The agglomeration, the layering, the beauty and the like.

(2) The safety is good. The talc used in the invention is natural mineral, and is nontoxic and pollution-free. Preparation of nano TiO₂The raw material reagents used in the process are nontoxic, safe and reliable.

(3) The process is simple. The hydrothermal method used in the invention is simple to operate and convenient to work.

(4) Easy popularization and application. The invention has simple process, convenient operation and easy learning, mastering, popularization and application.

(5) Has wide application and remarkable economic and social benefits. With the recognition of the harm of ultraviolet rays to human bodies, ultraviolet resistant materials are receiving more and more attention, and especially, compared with chemical ultraviolet resistant agents, physical ultraviolet resistant agents are safer and more stable. Hair brushTalc-loaded nano TiO prepared by Ming method₂The composite uvioresistant agent better solves the problem of the prior nano TiO₂The method has important significance for the development of the ultraviolet-resistant material industry, and has wide application prospect and remarkable economic and social benefits.

5. Description of the drawings

FIG. 1: the X-ray powder crystal diffraction spectrum of the talc sample adopted by the invention.

FIG. 2: nano TiO prepared by hydrothermal method₂Ultraviolet shielding performance (Abs-absorbance, T-ultraviolet shielding rate).

FIG. 3: nano TiO prepared by hydrothermal method₂The X-ray powder crystal diffraction spectrum of (1).

FIG. 4: nano TiO prepared by hydrothermal method₂Scanning Electron Microscope (SEM) photograph of (a).

FIG. 5: talc and nano TiO₂And talc-supported nano TiO₂And an X-ray powder crystal diffraction spectrum of the composite uvioresistant agent.

FIG. 6: talc (a) and talc-supported nano TiO₂Scanning electron microscope analysis photo of the anti-ultraviolet agent (b).

FIG. 7: talc, industrial TiO₂TiO 2 nanoparticles₂Talc supported nano TiO₂Ultraviolet-visible light spectrum contrast diagram (Abs-absorbance, T-ultraviolet shielding rate) of the composite uvioresistant agent.

6. Detailed description of the preferred embodiments

Example 1: talc-loaded nano TiO₂Composite uvioresistant agent and its prepn process

The method comprises the steps of preparing talc-loaded nano TiO by a hydrothermal method by using natural flaky mineral talc as a carrier mineral raw material, wherein the talc mineral raw material is talc single mineral aggregate (figure 1), crystals are irregular flaky, the scale size is 2-6 mu m (figure 6a), and the chemical components are shown in Table 3₂The preparation process of the composite uvioresistant agent comprises the following 5 steps:

(1) preparing a titanium sulfate solution: selecting titanium sulfate (Ti (SO)₄)₂) Preparing titanium sulfate into 0.3-1.2 mol/l titanium sulfate solution as a titanium source, and magnetically stirring for 30min to fully dissolve the titanium sulfate solution;

(2) preparing a titanium sulfate-urea-talc mixed solution: adding a certain amount of urea into a titanium sulfate solution to enable the amount ratio of urea to titanium sulfate to be 1-3: 1, fully stirring for 1-2 h, and adding a proper amount of talc to enable TiO in a mixed system to be TiO₂The mass ratio of the talc to the talc is 0.5-2, the mixture is fully stirred for 1-2 hours, and ultrasonic oscillation is carried out for 30 min;

(3) hydrothermal reaction: pouring the titanium sulfate-urea-talc mixed solution into a polytetrafluoroethylene reaction kettle (the solution accounts for 70-80% of the kettle volume), placing the sealed hydrothermal kettle at the hydrothermal temperature of 140-200 ℃ for full reaction for 2-8 h, and after the reaction is finished, naturally cooling, pouring out supernatant in the reaction kettle to obtain a kettle bottom reaction product;

(4) washing to remove impurities: carrying out centrifugal washing on the reaction product by adopting a centrifugal washing device, washing by using distilled water twice, and washing by using absolute ethyl alcohol twice to remove impurities;

(5) drying the materials: transferring the reaction product after washing and impurity removal into a drying device, wherein the drying temperature is 105 ℃, and the drying time is 4-6 h, thus obtaining the talc-loaded nano TiO₂And (3) a composite anti-ultraviolet agent.

The detection result shows that the talc loaded nano TiO obtained by the method of the embodiment₂The composite uvioresistant agent has the following characteristics:

(1) FIG. 5 shows talc and nano TiO₂And talc-supported nano TiO₂The X-ray powder crystal diffraction spectrum of the composite uvioresistant agent can be seen, and the X-ray powder crystal diffraction spectrum of the composite uvioresistant agent, the talcum and the nano TiO can be seen₂In contrast, talc supported nano TiO₂Talc and nano TiO can be seen in XRD pattern of the composite uvioresistant agent₂The characteristic peaks of the two substances are generated because no new peak is generated, which indicates that the two substances are physically compounded.

(2) FIG. 6 shows talc (a) and talc-supported nano TiO₂Scanning Electron Microscope (SEM) photo of the uvioresistant agent (b) shows that the surface of the talc flake is loaded with nano TiO₂The particles are uniform in particle size distribution, are spherical, have the size of about 30-50 nm, and obviously improve the agglomeration phenomenon.

(3) FIG. 7 shows talc and industrial TiO₂TiO 2 nanoparticles₂Talc supported nano TiO₂The ultraviolet-visible light spectrum contrast chart of the composite uvioresistant agent can show that: first, talc has poor UV resistance, industrial TiO₂Secondly, the performance requirements of the anti-ultraviolet agent are not met. Second, with industrial TiO₂In contrast, nano TiO₂The absorbance of the ultraviolet region is obviously increased, the uvioresistant performance is excellent, the ultraviolet shielding rate can reach 95 percent, the transmittance of the visible light region is lower, and the whiteness is proved to be higher than that of industrial TiO₂And decreases. Thirdly, nano TiO is loaded on talc₂Absorbance of uvioresistant agent in ultraviolet region and nanometer TiO₂The absorbance has little difference, the ultraviolet shielding rate can reach 97 percent, which shows that the ultraviolet resistance is excellent, and the transmittance to visible light is better than that of the prepared nano TiO₂The transparency was good.

The detection results show that the talc-loaded nano TiO prepared by the embodiment of the invention₂The composite uvioresistant agent can overcome the defects of the existing nano TiO₂Easy agglomeration and the like, obviously improves the nano TiO₂The ultraviolet-resistant or ultraviolet-resistant shielding material has good market prospect and social and economic benefits.

Fund project: the work subsidies national science fund projects (41572038, 41972039) and scientific research projects (16TD0011) funded by the university and development hall in Sichuan.

Claims (1)

1. Talc-loaded nano TiO₂A composite uvioresistant agent is prepared from talc as carrier mineral through hydrothermal preparing process₂The composite uvioresistant agent is characterized in that:

(1) preparing a titanium sulfate solution: selecting titanium sulfate (Ti (SO)₄)₂) Preparing titanium sulfate into 0.3-1.2 mol/l titanium sulfate solution as a titanium source, and magnetically stirring for 30min to fully dissolve the titanium sulfate solution;

(2) preparing a titanium sulfate-urea-talc mixed solution: adding a certain amount of urea into a titanium sulfate solution to enable the amount ratio of urea to titanium sulfate to be 1-3: 1, fully stirring for 1-2 h, and adding a proper amount of talc to enable the urea to be mixed with the titanium sulfateTiO in mixed system₂The mass ratio of the talc to the talc is 0.5-2, the mixture is fully stirred for 1-2 hours, and ultrasonic oscillation is carried out for 30 min;

(3) hydrothermal reaction: pouring the titanium sulfate-urea-talc mixed solution into a polytetrafluoroethylene reaction kettle (the solution accounts for 70-80% of the kettle volume), placing the sealed hydrothermal kettle at the hydrothermal temperature of 140-200 ℃ for full reaction for 2-8 h, and after the reaction is finished, naturally cooling, pouring out supernatant in the reaction kettle to obtain a kettle bottom reaction product;

(4) washing to remove impurities: carrying out centrifugal washing on the reaction product by adopting a centrifugal washing device, washing by using distilled water twice, and washing by using absolute ethyl alcohol twice to remove impurities;

(5) drying the materials: transferring the reaction product after washing and impurity removal into a drying device, wherein the drying temperature is 105 ℃, and the drying time is 4-6 h, thus obtaining the talc-loaded nano TiO₂And (3) a composite anti-ultraviolet agent.

The talc is a magnesium silicate mineral with a 2:1 type trioctahedral layered structure, and the chemical formula of the crystal is Mg₃[Si₄O₁₀](OH)₂The characteristic peak of the X-ray powder crystal diffraction analysis is

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