RU2518124C2 - Composition for obtaining matrix with photocatalytic activity - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to hybrid organo-inorganic nanocomposite coatings. Composition for obtaining matrix with photocatalytic activity includes sol based on element organic compound and epoxy component, in which as element organic compound in composition used is titanium alkoxide with the following component ratio, wt %: titanium alkoxide 30-70, epoxy sol component 30-70, and as epoxy compounds composition contains diglycidyl ether of dicyclohexyl propane, and as titanium alkoxide - tetrabutoxytitanium.

EFFECT: creation of composition for obtaining coating, possessing photocatalytic activity, formation of active forms of oxygen takes place under action of ultraviolet light.

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Description

The invention relates to composite materials, namely to hybrid organo-inorganic nanocomposite coatings, in particular to coatings formed on the basis of hybrid sols that have increased photocatalytic activity. The composition can be used in the form of coatings to protect the building structures of urban infrastructure and unique cultural heritage from biodegradation.

To give the compositions bioactivity, various bioadditives are used - biocides. The most widely used so-called hard biocides:

ammonium, tin-containing, organosilicon and other compounds. (Richardson B. A. Control of microbial growth on stone and concrete // ln "Biodeterioration". Elsevier Applied Science. 1988. P.101-106.) Their inhibitory effect on microorganisms is short-term and often leads to the selection of new, more aggressive strains. The use of toxic chemical biocides is dangerous for the environment and maintenance personnel.

Most preferred is the use of “soft” biocide photocatalysts; synthetic analogues of chlorophyll-phthalocyanines and metal diphthalocyanines. (Artemyev I.M., Ryabchuk V.K. Introduction to the heterogeneous photocatalysis of St. Petersburg: St. Petersburg State University, 1999. P.304.)

Known epoxysiloxane compositions used as restoration materials for protection against adverse environmental conditions (Cardiano P., Sergi S, Lazzari M., Piraino P. Epoxy-silica polymers as restoration materials // J. Polymer. 2002. 43. No. 5 P. 6635-6640; P. Cardiano, P. Mineo, S. Sergi, RC Ponterio, M. Triscari, P. Piraino Epoxy-silica polymers as restoration materials. Part II // Polymer. 44. 2003. P. 4435 -4441), which are formed on the basis of aminopropyltriethoxysilane and glycidoxypropyltrimethoxysilane or epoxy-diane uncured resin. The disadvantage of this composition is the lack of bioactivity.

A known composition for producing a biologically stable coating according to the patent of the Russian Federation No. 2382059, comprising a sol based on a water-alcohol solution of tetraethoxysilane - a silicate component with the addition of inorganic acid and, if necessary, metal salts, which is characterized in that it additionally contains epoxy compounds in the ash - epoxy component and modifying additive - detonation nanodiamond with a size of nanoparticles and their aggregates 3-100 nm in the following ratio of components, wt.%:

silicate sol component 49.75-49.99 epoxy sol component 49.75-49.99 detonation nanodiamonds 0.02-0.5

As the epoxy component, this composition may contain an aliphatic epoxy resin and an epoxy-dianic uncured resin, and the modifying additive may be in the form of an aqueous suspension, diamond powder or diamond mixture.

This composition is adopted as a prototype of the claimed invention.

This sol composition is used to obtain a coating that protects unique cultural heritage from biodegradation by introducing a biocidal additive - detonation nanodiamond into it, since it does not have photocatalytic activity.

The objective of the invention is to provide a composition for coating formed on the basis of epoxy titanate sol and having photocatalytic activity against mold fungi, most common in the air in large cities, at ambient temperature (+ 15-30 ° C) due to the introduction of composition of sols of titanium alkoxide.

The invention is expressed in the following set of essential features, sufficient to achieve the above technical result provided by the invention.

A composition for producing a matrix with photocatalytic activity, comprising a sol based on an organoelement and an epoxy component, in which titanium alkoxide is used as an organoelement in the composition in the following ratio, wt.%: Titanium alkoxide - 30-70, epoxy component sol - 30-70, characterized in that the composition contains dicyclohexylpropane diglycidyl ether as epoxy compounds and tetrabutoxytitanium as titanium alkoxide.

The introduction of an epoxy component into the composition of the sol makes it possible to obtain mechanically strong layers that are closely adjacent to the surface without high-temperature processing, which facilitates the coating process.

Titanium alkoxide is an essential component of the composition. Moreover, it can be introduced into it in the form of tetrabutoxy titanium.

Introduction to the composition of the claimed composition of titanium alkoxide enhances the photocatalytic activity of the epoxy titanium matrix formed from Zola, due to the ongoing photocatalytic reactions under the influence of ultraviolet light, resulting in the formation of ozone and other reactive oxygen species (singlet oxygen). In this regard, there is an energetic effect on the cell of a simple microorganism (micromycetes of mold), which suppresses its vital activity. It has been revealed that charge transfer catalysts exhibit the properties of a “soft” biocide. They inhibit the growth of a number of aggressive molds, the most common in the air of large cities.

The lower limit of the introduction of titanium alkoxide - 30 wt.% Is determined by the decrease in the photocatalytic activity of the coating. The introduction of titanium alkoxide in an amount of more than 70 wt.% Is impractical and leads, on the one hand, to a deterioration in the mechanical strength of the coating, and on the other hand, can affect the color of the protected material.

As a result of the use of such a composition, a new nanocomposite coating is obtained to protect stone monuments of cultural heritage from the effects of a number of aggressive mold fungi that are most often found in the air of large cities.

The invention is illustrated by examples of the preparation of the claimed compositions.

Example 1. A composition containing:

tetrabutoxy titanium 30 wt.% epoxy sol component 70 wt.%

The inventive composition can be prepared as follows.

Synthesis of sol, including:

- preparation of an alcoholic solution of tetrabutoxytitanium (TBT): 0.43 g of acetylacetone, 2.80 g of ethyl cellosolve are successively added to 1.45 g of TBT and intensively mixed;

- preparation of the resulting sol containing all components: 0.49 g of 1N is added to 4.68 g of an alcoholic solution of TBT. nitric acid solution and mix vigorously; 1.45 g of dicyclohexylpropane diglycidyl ether (EPONEX 1510) and 0.20 g of BF ₃ acid are successively added to this mixture, followed by thorough mixing. The molar ratio of components in the resulting ash is as follows:

Ti (OC ₄ H ₉ ) ₄ : EPONEX 1510: C ₅ H ₈ O ₂ : C ₄ H ₁₀ O ₂ : BF ₃ : H ₂ O: HNO ₃ = 1: 7: 0.5: 0.2: 0.4: 1.5: 0.001.

2. Aging sol. The sol is kept before further use for 3 hours in air (in a closed container) at room temperature.

3. The formation of coatings. Coating on protected surfaces is carried out by the paint and varnish method (brush, spray, etc.).

4. Drying. The drying of the formed coatings takes place in air at ambient temperature.

Example 2. Obtaining a composition containing:

tetrabutoxy titanium 50 wt.% epoxy component 50 wt.%

The composition is prepared analogously to example 1. The molar ratio of the components in the resulting ash is as follows:

Ti (OC ₄ H ₉ ) ₄ : EPONEX 1510: C ₅ H ₈ O ₂ : C ₄ H ₁₀ O ₂ : BF ₃ : H ₂ O: HNO ₃ = 1: 5: 0.5: 0.2: 0.4: 1.5: 0.001.

Example 3. Obtaining a composition containing:

tetrabutoxy titanium 70 wt.% epoxy component 30 wt.%

The composition is prepared analogously to example 1. The molar ratio of the components in the resulting ash is as follows:

Ti (OS ₄ H ₉ ) ₄ : EPONEX 1510: C ₅ H ₈ O ₂ : C ₄ H ₁₀ O ₂ : BF ₃ : H ₂ O: HNO ₃ = 1: 3: 0.5: 0.2: 0.4: 1.5: 0.001.

The photocatalytic activity of the obtained nanocomposite coatings was determined using a Optek gas analyzer. The activity of the coatings was evaluated as a percentage relative to the activity of the TiO ₂ Degussa photocatalyst. In addition, the mechanical strength of the coatings was evaluated without heat treatment visually in points.

The test results of coatings based on epoxysilicate sol (by the method of the closest analogue) and nanocomposite coatings obtained according to the above examples are summarized in table 1.

Table 1. Effect of the concentration of tetrabutoxy titanium on the photocatalytic activity and mechanical strength of the obtained nanocomposite coatings The properties The concentration of tetrabutoxytitanium in the composition of Zola, wt.% 0 (prototype) thirty fifty 70 photocatalytic activity of coatings in% relative to the activity of TiO ₂ "Degussa" 0 5 twenty fifty mechanical strength of coatings without heat treatment, in points 5 5 5 four

The test results indicate the effectiveness of using tetrabutoxytitanium as a sol component, which gives photocatalytic activity to formed coatings due to photocatalytic reactions under the influence of ultraviolet light, resulting in the formation of reactive oxygen species that inhibit the activity of mold fungi. It was revealed that the concentration of TBT has a significant effect on the photocatalytic properties of coatings. Activity is established in all TBT coatings.

The proposed composition allows, on the basis of an epoxy titanate sol, to create a new nanocomposite coating with photocatalytic properties by introducing titanium alkoxide (TBT) into the composition of the sol. As a result of the application of the invention, the epoxy titanate coating can be given enhanced photocatalytic properties, which undoubtedly makes it promising for the protection of building structures of urban infrastructure and unique cultural heritage sites.

Claims (1)

A composition for producing a matrix with photocatalytic activity, comprising a sol based on an organoelement compound and an epoxy component, in which titanium alkoxide is used as an organorganic compound in the composition in the following ratio, wt.%:
titanium alkoxide 30-70 epoxy sol component 30-70,
characterized in that the composition contains dicyclohexylpropane diglycidyl ether as epoxy compounds, and tetrabutoxytitanium as titanium alkoxide.