NL8601155A - METHOD FOR AT LEAST PARTIAL ELIMINATION OF AN OPTICAL BLEACHING EFFECT. - Google Patents

Abstract

In a process for extinguishing the optical brightening effect produced on a substrate by an optical brightening agent or preventing optical brightening effects from being produced on a substrate by an optical brightening agent, the substrate is brought into contact with an UV-absorber which is subsequently fixed on the substrate, both steps being effected either before or after the treatment of the substrate with the optical brightening agent. The UV-absorber may be applied to the substrate before, during or after dying or printing the substrate.

Description

«. . * - 1 -

Method for at least partially canceling an optical bleaching effect.

♦

The present invention relates to a method of eliminating or preventing the fluorescence of optically bleached substrates.

As is known, an optical brightener absorbs invisible ultraviolet light and emits it back into the blue or green portion of the visible spectrum. * The light emitted again masks the unwanted, yellow hue of textiles or other substrates. Therefore, optically bleached materials appear to be whiter than untreated substrates and optical brighteners are widely used to enhance the white effect of substrates such as textiles, paper, leather, coatings, pigments, etc.

Nevertheless, the presence of an optical brightener is sometimes undesirable. For example, if an optically bleached textile material is over-dyed or reprinted with a dye, the overall effect obtained with the textile material in daylight is due to the absorption of the dye used and, moreover, the fluorescence of the optical brightener. When exposing such dyeings or prints to artificial light which contains virtually no ultraviolet light, there is no sign of fluorescence and the observer notes a large change in color.

Consequently, the invention relates to a method for at least partially canceling the optical bleaching effect caused on a substrate by an optical brightener or preventing the occurrence of optical bleaching effects on a substrate by an optical brightener, which method comprises contacting the -> A ». + -Λ - * 4

. V

- 2 - substrate with a UV-absorbing material and then fixing this material on the substrate, both steps being carried out either before or after the treatment of the substrate with an optical brightener.

By "UV absorbing material" is meant a material that strongly absorbs light in the near UV range - (<400 nm, especially within 250-350 nm), without significant radiation of longer wavelengths occurring again The expression "optical bleaching effect" as used in this specification refers to the fluorescence effect of the optical bleaching agent.

Minor UV absorbing materials include benzotriazole derivatives, for example, 2- (2'-hydroxyphenyl) -benzotriazole derivatives, such as 2- (2 * -hydroxy-31-tert-butyl-5'-15-methylphenyl) -5-chlorobenzotriazole, benzophenone derivatives. Example 2-hydroxybenzophenone derivatives, the 21, 44 and / or 5 positions of which are optionally further substituted, such as 4-chloro-2,2 ', 4'-trihydroxybenzophenone, 2,2', 4-trihydroxybenzophenone, 2,4-dihydroxy 4'-methoxy-benzophenone, 2,2 ', 4,4'-tetrahydroxybenzo-20 phenone, 2,4-dihydroxybenzophenone or 2-hydroxy-4-methoxy-benzophenone, benzoic acid derivatives, for example resorcinol monobenzoate, salicylic acid esters, for example 4- Alkyl phenyl salicylate, dibenzoyl benzene derivatives, for example p-di (4-hydroxy salicyloyl) benzene or 2,4-dibenzoyl resorcinol, α-cyanoacrylic acid ester derivatives and benzylidene malodinitriles. Such ultraviolet light absorbing materials are known and described, for example, in US 3,214,463 and 3,383,241, DAS 1,101,437 and 1,213,407 and British Patent 796,003.

According to the invention, a mixture of ultraviolet light absorbing materials can also be used.

The ultraviolet light absorbing material *

... j, T

It is suitably applied from an aqueous medium, depending on its water solubility, it can be used as an aqueous solution or in the form of an emulsion or dispersion in an aqueous medium. The emulsions are conveniently prepared by dissolving the ultraviolet light absorbing material in an organic solvent, for example, gasoline, and adding the resulting solution to water, preferably in the presence of an emulsifier. Recommended emulsifiers are non-ionic emulsifiers, for example oxyalkylated products, preferably ethoxylated products, of alcohols with 8-20 carbon atoms, phenols substituted with 4-12 carbon atoms, fatty acids with 8-20 carbon atoms or castor oil.

Preferably, the nonionic emulsifiers contain 5-50, especially 5-30, ethyleneoxy units. As already mentioned, the ultraviolet light absorbing material can also be used in the form of an aqueous dispersion of fine particles, optionally in the presence of a dispersant. Suitable dispersants are those used for dispersing dyes, for example lignin sulfonates or formaldehyde naphthalene sulfonic acid condensation products.

The ultraviolet light absorbing material / can be applied by known methods suitable for the type of ultraviolet light absorbing material used, such as are generally used for dyeing or printing, for example by exhaustive extraction from a longbat at a temperature between 20 and 140 ° C, impregnation and residence at a temperature between 20 and 90 ° C, for 30 minutes to 48 hours, depending on the residence temperature, impregnation and fixing with saturated steam, supersaturated steam at a temperature between 160 and 190 ° C or warm, dry air at a temperature between 160 and 22 ° C, or treatment with a high frequency or thermal contact. The ultraviolet light absorbent material can also be applied by known printing methods, for example thermal printing, in combination with organic polymers, for example surface coatings on both oil and water basis, or by pigment printing.

The method used for applying and fixing the ultraviolet light absorbing material and the amount of this material to be applied depend on the substrate to be treated, the optical brighteners used or to be used, the properties of the ultraviolet light absorbing material. and the type of dyes to be used, if any. In general, good compensating properties are obtained when the ultraviolet light absorbing material is used in an amount of 0.1-5% by weight, based on the weight of the substrate.

According to the invention, the ultraviolet light absorbing material can be applied to an optically bleached substrate. According to a recommended embodiment, the ultraviolet light absorbing material is applied before, during or after dyeing or printing the optically bleached material, in particular after dyeing or printing. The ultraviolet light absorbing material can also be applied to the substrate for optical bleaching. According to a recommended embodiment, the ultraviolet light absorbing material is applied to an unbleached material before, during or after dyeing or printing with a dye or a mixture of dyes.

The nature of the dyeing or printing process applied to the material in connection with the treatment with the ultraviolet light absorbing material is not critical as long as the dyes used and the dyeing and printing conditions are compatible with the ultraviolet light absorbing employed. , material.

"

. - J

- 5 -

Today, optical brighteners are often included in household laundry detergents- If dyed or printed clothes are washed with such a detergent, the color has changed after drying, especially in case of light dyeing or printing, such as with yellow or beige 5 colors- A such drawback is avoided if the dyed or printed articles of the invention are treated with an ultraviolet light absorbing material and washed at a later stage with a detergent containing an optical brightener.

According to the invention, the bleaching effect of an optical brightener can be eliminated or significantly reduced over the entire surface of the substrate or only locally. Thus, the ultraviolet light absorbing material can be applied topically by locally printing an optically bleached material or a material to be optically bleached. When exposed to ultraviolet light, the material treated according to the invention shows a fluorescent pattern, such as are used for example in theaters or dance clubs or for safety signals.

The method according to the invention is used to prevent or eliminate the brightening effects brought about by different classes of optical brighteners, for example anionic or cationic optical brighteners or dispersion-type optical brighteners, such as are used in household detergents 1, in waxes. or bleaching agents for the pretreatment of cellulose fibers or other natural or synthetic fibers, or for the optical bleaching of bulk paper or synthetic fibers. Examples of optical brighteners which eliminate or reduce the bleaching or fluorescent activity of the invention are zijn '* - δ - bis (triazinylamino) stilbene disulfonic acids, triazolyl derivatives of stilbene sulfonic acids, bis stilbenes, pyrazoline derivatives, naphthalimines, amino coumarins, oxacyanines , oxazoles, benzoxazoles or bis (benzimidazolyl) derivatives.

The method according to the invention can be applied to any type of material that can be optically bleached, such as, for example, textile fibers, paper or leather.

The textile fibers can be in any conventional form, such as, for example, yarns, woven or knitted materials or non-woven products. Examples of textile substrates are those containing wool, cotton, linen, silk, synthetic polyamides, polyesters, cellulose acetate or triacetate, polyacrylonitrile, polyvinyl chloride or polyolefin fibers, or mixtures thereof.

It may be beneficial to conduct a preliminary study to select the ultraviolet light absorbing material which is particularly effective with the substrate to be treated in order to achieve the optimum operating conditions. An ultraviolet light absorbing material which is particularly effective with a substrate containing polyester fibers is, for example, an ultraviolet light absorbing material of the benzotriazole type, preferably 2- (2, -hydroxy-3, tert-butyl-5'-methylphenyl) - 5-chlorobenzotriazole.

According to a recommended embodiment of the invention, the ultraviolet light absorbing material is applied to an optically bleached substrate, in particular a textile substrate, in which the optical brightener is either incorporated in the spinning mass if the textile substrate contains synthetic fibers or is applied in a pre-treatment step, 30, for example, a bleaching step. It may also be beneficial to apply an ultraviolet light absorbing material to such material after dyeing or printing, including fixation of the dyes. , ..

- 7 - Λ.

To apply. The method according to the invention is particularly suitable for the treatment of textile materials containing synthetic fibers, in particular polyester fibers.

The ultraviolet light absorbing material is selected to eliminate, preferably completely, or prevent the optical bleaching effects of optical brighteners used for such synthetic fibers. In the case of polyesters, the ultraviolet light absorbing material used to cancel or prevent the optical bleaching effects of a dispersion optical bleach is preferably a benzotriazole derivative.

In the following examples, all parts and percentages are parts by weight and percentages by weight, respectively.

Example I

A polyester yarn, which had been optically bleached in bulk, was treated in an cheese and cone dyeing machine with an aqueous bath containing, per 1000 parts, 0.17 parts of 2- (2, -hydroxy-3, -tert.-butyl-) 5I-20-methylphenyl) -5-chlorobenzotriazole dispersed in water contains 0.5 parts of ammonium sulfate and 0.3 parts of glacial acetic acid.

The liquid to material ratio was 30: 1. The temperature of the treatment bath was raised from 404125 ° C for 40 minutes and then the yarn was treated at 125 ° C for 30 minutes. After cooling, the yarn was rinsed and prepared for dyeing.

When exposed to ultraviolet radiation, the treated yarn showed no fluorescence.

·. *

> V

- 8 -

Example ii

A 100% polyester fabric which had previously been optically bleached with C.I. by a thermosol process. Fluorescent Brightening Agent 330, was printed in a stripe pattern with a printing paste containing, per 1000 parts, 4 parts of 2- (21-hydroxy-3'-tert-butyl-5'-methyl-phenyl) -5-chlorobenzotriazole in the form of an aqueous dispersion ^ 400 parts of a 13% thickening preparation based on guar (Indalca H 735, Cesalpinia-Hercules SA

Bergamo, Italy) and water in an amount sufficient to make up to 1000 parts.

IS After drying, the printed fabric was treated with superheated steam at 175 ° C for 7 minutes. Then the fabric was first rinsed warm and then cold and finally dried. When exposed to ultraviolet light, the printed fabric showed a dark striped pattern on a clear white-blue background. .

Example III

66 polyamide knits were treated which had previously been optically bleached with the C.I. by a thermosol process. Fluorescent Brightening Agent 328, 30 minutes at 98 ° C and pH 5 with a bath containing 0.5 wt%, based on the weight of the polyamide goods, of 2-hydroxy-4-n-octoxybenzophenone in white spirit Emulsified in water with oleic acid polyglycol ester. After the completion of the treatment, the knitted goods were rinsed with cold water.

When exposed to ultraviolet lift. The treated knitwear did not exhibit fluorescence.

- V ^. i V

- 9 -

Example IV

Repeating the procedure of Example III, but replacing the 2-hydroxy-4-n-octoxybenzophenone emulsion with a 0.5% aqueous solution of 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid, the fluorescence of the 66 polyamide slurry had virtually disappeared.

Example V

A polyacrylonitrile fabric, which had previously been exhaustively optically bleached with C.I. Fluorescent 10 Brightening Agent 340, was treated for 60 minutes at 98eC and pH 6 with a bath containing 1% by weight, based on the weight of the fabric, of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone in the aqueous dispersion form. After the treatment, the fabric was first rinsed warm and then cold.

When exposed to ultraviolet radiation, the treated tissue showed significantly less fluorescence.

Example VI

Knitted articles, made from pH 66 textured yarn, were placed in a 1: 15 goods to liquid ratio in a liquid containing 0.1% of the dye C.I. Acid Orange 145 and 1.0% sodium 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone-5-sulfonate 25 and adjusted to pH 4.5 with acetic acid.

The percentage is based on the dry weight of the knitted goods. The temperature of the bath was increased from 60 to 98 ° C at a rate of 1 ° C per minute, under continuous mechanical movement, and dyeing was continued for another 30 minutes at 98 ° C. Then the materials were first rinsed at 50 ° C, then cold rinsed and finally at 80 ° C

* · «. \ • -v - <V v - 10 - dried.

If the dyed articles were washed at a liquid to goods ratio of 30: 1 for 30 minutes at 40 ° C with 3 g per liter of a commercially available (r} 5 fine laundry detergent (Wollana®, registered trademark Mark, Eswa AG, Switzerland) and then rinsed and dried, no noticeable change of color from an unwashed article was observed.

Knitwear was dyed by the method described above, however, in the absence of the benzophenone derivative (ultraviolet light absorbent material) and then washed with the same household detergent under the same conditions as mentioned above. Compared to an unwashed article, the washed article showed a significant color change.

Claims (13)

A method for at least partially canceling the optical bleaching effect caused by an optical bleaching agent on a substrate or for preventing optical bleaching effects from an optical bleaching agent occurring on a substrate, characterized in that the contacts substrate with an ultraviolet light absorbing material and then fixes the ultraviolet light absorbing material to the substrate, performing both steps before or after treatment of the substrate with the optical brightener. 2. Process according to claim 1, characterized in that the ultraviolet light absorbing material used is benzotriazole derivatives, benzophenone derivatives, benzoic acid derivatives, esters of salicylic acid, dibenzoylbenzene derivatives, ester derivatives of α-cyanoacrylic acid and / or benzylidene malodinitriles. 3. Process according to claim 2, characterized in that as ultraviolet light absorbing material 20 2- (2'-hydroxyphenyl) -benzotriazole derivatives, 2-hydroxybenzophenone of the ivates, of which the 2 ', 4', 4 and / or 5 positions optionally further substituted, resorcinol monobenzoate, alkyl phenyl salicylate, p-di (4-hydroxy salicyloyl) benzene and / or 2,4-dibenzoyl resorcinol. 25 Process according to Claim 3, characterized in that the ultraviolet light-absorbing material is 2- (2'-hydroxy-31-tert-butyl-5'-methylphenyl) -5-chlorobenzotazole, 4-chloro-2, 2,4'-trihydroxybenzophenone, 2,2'-4-tri-30 hydroxybenzophenone, 2,4-dihydroxy-4'-methoxybenzophenone, 2,2 ', 4,4'-V-12-tetrahydroxy-benzophenone, 2,4-dihydroxy-benzophenone and / or 2-hydroxy-4-methoxy-benzophenone. Method according to any one of the preceding 2 claims, characterized in that the ultraviolet light absorbing material is used as an aqueous solution or in the form of an emulsion or dispersion. A method according to any one of the preceding IQ claims, characterized in that the ultraviolet light absorbing material is applied to the substrate by means of extraction, impregnation or printing methods. A method according to any one of the preceding claims, characterized in that the ultraviolet light absorbing material is applied to an optically bleached substrate. A method according to any one of claims 1-6, characterized in that the ultraviolet light absorbing material is applied for optical bleaching of the substrate. 9. A method according to any one of the preceding claims, characterized in that the ultraviolet light is applied to the absorbing material before, during or after / dyeing or printing the substrate. Method according to one of the preceding claims, characterized in that textile fibers, paper or leather are used as the substrate. 30 11. Process according to claim 10, characterized in that the textile substrate containing a polyester, polyamide and / or polyacrylonitrile is used as the substrate. 12. Method as described in the description, with reference to the previous examples 1-6. A substrate obtained using a method according to any one of the preceding claims.