WO2003022742A1

WO2003022742A1 - Protective composition against ultraviolet rays

Info

Publication number: WO2003022742A1
Application number: PCT/FR2002/003033
Authority: WO
Inventors: Alain Demourgues; Jean-Yves Kempf
Original assignee: Rhodia Electronics And Catalysis
Priority date: 2001-09-07
Filing date: 2002-09-06
Publication date: 2003-03-20
Also published as: FR2829482B1; FR2829482A1

Abstract

The invention concerns a protective composition against ultraviolet rays, characterized in that it is based on a titanium oxyfluoride of formula (1): Ti>1-x1-4x2+4x<, wherein 0 </= x </= 0.12. The invention also concerns a plastic, paint, glass or cosmetic product composition comprising the oxyfluoride of formula (1) as protective agent against ultraviolet rays.

Description

COMPOSITION FOR PROTECTION AGAINST ULTRAVIOLET RAYS

The present invention relates to a composition for protection against ultraviolet rays.

We know that ultraviolet radiation is harmful to living organisms. They can for example be the cause of skin cancer in humans. They can also cause degradation of organic media such as plastics.

Organic products have been proposed which have protective effects with respect to this radiation. However, the stability of these products is often not satisfactory. This is why it has also been proposed inorganic products such as titanium oxide which have good stability. Titanium oxide has drawbacks, however. First of all, it has photocatalytic properties which makes it emit free radicals and which can accelerate the degradation process in certain polymer matrices. In addition, to have anti-UV properties, it must have a relatively large particle size, for example greater than 50 nm. In such a case, the titanium oxide is no longer transparent and therefore gives color to the medium in which it is incorporated.

There is therefore a need for an inorganic anti-UV agent which does not have photocatalytic properties and which is possibly transparent. The object of the invention is to provide such a product.

For this purpose, the invention relates to a composition for protection against ultraviolet rays, characterized in that it is based on a titanium oxyfluoride of formula (1):

where 0 <x <0.12.

The invention also relates to the use as a UV-protective agent of a titanium oxyfluoride corresponding to formula (1) above.

Other characteristics, details and advantages of the invention will appear even more completely on reading the description which follows, various concrete but nonlimiting examples intended to illustrate it as well as the attached drawing in which:

- The single figure is a graph giving the measurement results of the diffuse reflection coefficient as a function of the wavelength for products according to the invention.

The invention is based on the discovery of the anti-UV properties of titanium oxyfluoride of formula (1) given above.

This oxyfluoride can be stoichiometric, it is the case where x = 0, or not. More particularly, x can verify the relation 0 <x <0.12 and even more particularly 0.02 <x <0.12.

This oxyfluoride can also have a density of between 2.90 g. cm ^"3 and 2.99 g. cm ^{" 3} , this volume mass being measured using the principle of Archimedes' thrust on the one hand in gaseous medium (Argon U) and on the other hand in liquid medium using bromobenzene . It has an average particle size generally of at most 2 μm, preferably of at most 1 μm. This size is measured by scanning electron microscopy (SEM).

The oxyfluoride can be prepared by the action of hydrofluoric acid HF or ammonium fluoride in an aqueous medium on a titanium compound. As titanium compound, it is possible to use an anatase or rutile type oxide or a TiOCI ₂ oxychloride or a TiOS0 ₄ oxysulfate. These compounds can be used in solid form, in the case of oxides generally, or in liquid form for example oxychloride. It is also possible to start from a colloidal suspension of titanium oxide. The reaction is preferably carried out hot, by thermohydrolysis, for example between 80 ° C and 100 ° C over a period which can range from ten hours to 4 days in particular. It is possible to work with an excess of HF or ammonium fluoride. At the end of the reaction, the product is filtered and then dried, for example at 100 ° C. The characteristics of the oxyfluoride obtained, in particular the value of x given above, depend on the rate of OH ^" of the solid starting titanium compound or on the pH of the solution of this compound when the latter is used in liquid form, the molar concentration of titanium, the concentration of HF or of ammonium fluoride and the particle size of the starting titanium compound when the latter is used in solid form.

The product obtained crystallizes in the cubic system and the crystal lattice is of Re0 ₃ type (space group: Pm3m, a = 3.80Â). The product has absorption properties in the UVB (280-300nm) and UVA (300-400nm) range. In addition, it is not photocatalytic.

Owing to its anti-UV properties, oxyfluoride as defined above can be used as part of a composition for protection against UV rays.

Furthermore, oxyfluoride can be used as UV protection agent in plastics which can be of the thermoplastic or thermosetting type.

As thermoplastic resins, there may be mentioned, purely by way of illustration, polyvinyl polymers, styrene-butadiene, styrene-acrylonitrile copolymers, acrylic polymers, cellulose derivatives such as for example cellulose acetate, polyamides including polyamide 6. -6.

As regards thermosetting resins, mention may be made, for example, of phenoplasts, aminoplasts, epoxy resins and thermosetting polyesters.

Oxyfluoride can also be used in the same way in the field of paints and stains and more particularly in alkyd resins, acrylic resins, vinyl resins, aminoplast or phenolic resins, polyester resins, polyurethane resins, epoxy resins , silicone resins.

Oxyfluoride can also be used for its anti-UV properties in glasses and in cosmetic products or compositions.

Examples will now be given.

In these examples, the diffuse reflection measurements are carried out on a Perkin-Elmer Lambda 900 device. Incident radiation produced by a deuterium lamp and a halogen lamp is directed onto the surface of the powder sample. The phenomena of absorption, specular reflection and diffuse reflection can then occur. Radiation reflected in this latter mode is collected using a biconical accessory. Their intensity is measured relative to a spectral reference (no absorption and very high reflection factor over the 250 - 800 nm range) as a function of the wavelength.

Furthermore, the compositions of the products are determined by gravimetric analysis for titanium and, for fluorine, by dissolution and measurement of the level of this element by specific electrode. Densities are measured according to the method described above. EXAMPLE 1

As starting material, solid Ti0 ₂ (anatase) obtained by thermohydrolysis of the oxychloride TiOCI _{2 is used} at a pH close to 4 and at a temperature of 100 ° C. This Ti0 ₂ , which has an OH ^"level of at most 10% by mass, is reacted in water at a temperature of 80 ° C. for 12 hours, in the presence of hydrofluoric acid (HF) with a H ₂ 0 / HF volume ratio of 10 and in molar proportions F / Ti = 6. A product of composition Tio, 9θo, 6F ₂ , ₄ (x = 0.1) is obtained which crystallizes in the cubic system with a parameter of mesh a of 3.80 Å and a density Pexp = 2.94 g.cm ^"3 .

EXAMPLE 2

As starting material, solid Ti0 ₂ (rutile) obtained by thermohydrolysis of the oxychloride TiOCI _{2 is used} at a pH close to 2 and at a temperature of 100 ° C. This Ti0 ₂ , which has an OH ^"level of at most 5% by mass, is reacted in water at a temperature of 80 ° C. for 12 hours, in the presence of hydrofluoric acid (HF) with a H ₂ 0 / HF volume ratio of 10 and in molar proportions F / Ti = 6. A product of composition TiOF ₂ (x = 0) is obtained which crystallizes in the cubic system with a mesh parameter a of 3.82 Å and a density p _exp = 2.99 g.cm ^"3 .

EXAMPLE 3

The same solid Ti0 ₂ (rutile) from Example 2 is reacted and under the same conditions with the sole difference of the F / Ti molar proportions, the F / Ti molar ratio here being equal to 10. A product of composition is obtained

Ti ₀ , 96θo, ₈₄ F _2, i ₆ (x = 0.04) which crystallizes in the cubic system with a mesh parameter a of 3.82 A and a density p _exp = 2.95 g. cm ^"3 .

EXAMPLE 4

A starting solution of titanium oxychloride is used,

TiOCI ₂ . This aqueous solution is reacted at 80 ° C for 12 h in the presence of hydrofluoric acid (HF) in molar proportions F / Ti = 6 and at pH 2.

We obtain a product of composition Ti ₀₎ 9 ₈ Oo, 92F ₂ , o8 (x = 0.02) which crystallizes in the cubic system with a mesh parameter of a = 3.81 A and a density p _e χ _P = 2.98 g.cm ^"3 . In the appended figure, the four curves 1, 2, 3 and 4 represent the values of the diffuse reflection coefficient as a function of the wavelength for the products of Examples 1, 2, 3 and 4 respectively. It can be seen that the products have absorption properties in the range of 250 to 400 nm.

To test the photocatalytic behavior of the products according to the invention and to compare them to a commercial product, the photodegradation of phenol in water was chosen as the test reaction. In 400 cm ³ of an aqueous solution of initial phenol (Cphenoi = 50 mg.L ^"1, pH = 6) are added 400 mg of powdered product to be tested. The suspension is stirred, an oxygen bubble is formed and the whole is illuminated by a Mercury lamp (Philips HPK 125 W, 8.3x10 ^"6 Einstein. s ^{" 1} ). Eight samples of the suspension are taken at different reaction times (0, 10, 20, 30, 40 , 50, 60 and 75 minutes). After filtration through a Millipore filter (0.22 μm), UV - Visible absorption spectra between 200 and 600 nm are produced on the solutions. The device is an ISA Instrument device with a Xenon lamp.

In the case of Degussa Ti0 ₂ P25, which is a photocatalytic product, the different UV absorption spectra show over time the disappearance of the phenol absorption band and the appearance of the bands characteristic of the intermediate degradation products. such as hydroquinone and benzoquinone. On the other hand, in the case of the products of the above examples, no disappearance of the phenol absorption band nor of appearance of the bands corresponding to benzoquinone and to hydroquinone is observed. These products therefore do not show photocatalytic activity in the context of the oxidation of organic products.

Claims

1- Composition for protection against ultraviolet rays, characterized in that it is based on a titanium oxyfluoride of formula (1):

where 0 <x <0.12.

2- Composition according to claim 1, characterized in that it is based on a titanium oxyfluoride of formula (1) in which 0 <x <0.12 and more particularly 0.02 <x <0.12.

3- Composition according to claim 1 or 2, characterized in that it is based on a titanium oxyfluoride of formula (1) having a density between 2.90 g. cm ^"3 and 2, 99g. cm ^{" 3} .

4- Use as a protective agent against ultraviolet rays of a titanium oxyfluoride of formula (1):

where 0 <x <0.12.

5- Composition of the plastic, paint, glass or cosmetic type, characterized in that it contains, as agent for protection against ultraviolet rays, a titanium oxyfluoride of formula (1):

in which 0 <x ≤ 0.12.