SULFONATE BENZOTRIAZOLES AND THEIR USE IN POLYAMIDE

Abstract: A new class of sulfonated 2-(2'-hydroxyaryl)-2H-benzotriazole compounds and method for using them and other sulfonated hydroxyaryl benzotriazoles on nylon fibers to improve stain resistance and dye lightfastness has been discovered.

Description: SULFONATE BENZOTRIAZOLES AND THEIR USE IN POLYAMIDE BACKGROUND OF THE INVENTION This invention relates to sulfonated hydroxy benzotriazoles and their use to improve stain resistance and dye lightfastness in nylon fibers. Particularly useful is a new sulfonated 2-(2'-hydroxyaryl)-2H-benzotria- zole. The unsulfonated, precursor 2-(2'-hydroxyaryl) 2H-benzotriazole (hereinafter sometimes called hydroxy benzotriazole or aryl benzotriazole) is disclosed for use to protect organic substances from light-induced deterioration in U.S. 4,226,763 and U.S. 4,278,589. Use of sulfonated 2-(2'-hydroxyaryl)-2H-benzotriazoles as photostabilizing agents for natural and synthetic fibers is disclosed in a published international application under the Patent Cooperation Treaty (PCT), Publication No. wO 84/02365. SUMMARY OF THE INVENTION Surprisingly, it has been found that certain sulfonated aryl benzotriazoles also improve resistance of synthetic nylon fibers to staining by common anionic stain agents, such as food dyes containing Acid Red (Kool Aids), and these sulfonated aryl benzotriazoles improve lightfastness of dye on the nylon fiber. Some of these sulfonated aryl benzotriazoles are new compounds, namely, compounds having the structure EMI1.1 wherein R1, R2, R3 and R4 are independently the same or different alkyl groups and Zl and Z2 are alkyl or sulfonated aryl group, provided at least Z1 or Z2 is sulfonated aryl group. Mixtures of the compounds of the structure given above can be used to treat fibers to improve resistance to staining by anionic staining compounds such as Acid Red food dyes used in Kool Aid and also to improve lightfastness of dyes on nylon fibers. The fibers can be treated with the sulfonated hydroxy benzotriazoles of the structures given above, preferably in aftertreatment wherein the treatment is at a preferred pH of between about 2 and 5. The method for improving resistance to staining by anionic staining compounds and to improve lightfastness of dyes on nylon fibers, also comprises treating the fibers with an aqueous solution of sulfonated hydroxy benzotriazole at mild temperatures selected from the group consisting of EMI2.1 where R = tertiary alkyl or tertiary aralkyl, and M is a positive ion, such as alkali metal or hydrogen. EMI3.1 where R1, R2, R3, R4, Zl and Z2 are as defined above and EMI3.2 where M is a positive ion, such as alkali metal or hydrogen, R is tertiary alkyl or tertiary aralkyl and R5 is a short chain alkyl. The preferred method of treatment is an aftertreatment at a pH of between about 2 and 5. The preferred treatment temperature is between about 300C and 900C. The preferred time to aftertreat the fiber is after dyeing, preferably from about 10 to 30 minutes in duration. The compounds I, III and IV are also useful to improve properties of nylon materials in other forms, such as film. DETAILED DESCRIPTION OF THE INVENTION This invention relates to the preparation of novel chemical compounds and to novel methods of application to nylon (polyamide) materials (particularly polyamide fibers) which may or may not contain dyes wherein (a) the nylon materials and any incorporated dyes are afforded significant reduction in photodegradation and/or (b) the nylon materials are afforded significant improvement in resistance to many common stains, especially stains involving anionic species (such as FD & C Red 40, a common foodstuff dye). The novelty of the invention lies in (a) the chemical composition of certain of the additives which have not been previously reported and which provide significant and surprising photostability to polyamides and to dyes in polyamides at very low loadings relative to traditional photostabilizing additives, and (b) the method of application which provides for effective and durable incorporation into polyamides from aqueous solution under mild temperature conditions. Traditional agents employed to enhance photostability of dyed polyamides include compounds of structures such as EMI4.1 EMI5.1 Since these compounds are generally soluble only in organic solvents, the incorporation of such material into nylon poses serious problems. Surface application from organic solvents is a hazardous process and may result in a non-uniform coating of poor durability. Addition of these materials during extrusion may result in thermal degradation, may result in an ineffective distribution of material, and may result in loss of material due to volatility under extruder conditions. We have found that compounds of the general structure EMI5.2 where M is a positive cation, such as an alkali metal or hydrogen, R is tertiary alkyl, tertiary aralkyl or hydrogen, for example, EMI6.1 may be effectively incorporated into nylon fiber from aqueous solution at relatively low pH (preferably pH (3) and at modest temperatures (OOC - 100 C, preferably 20 700C). Nylon fibers or dyed nylon fibers treated with this material (0.05 - 5 percent, preferably 0.1 - 1 percent by weight) either before or after dyeing show dramatically enhanced photostability relative to untreated materials. In addition, these fibers demonstrate increased resistance to staining by certain common stains, especially those containing anionic groups. In addition, we have discovered that compounas of the general structures EMI6.2 where R = tertiary alkyl or tertiary aralkyl, and particularly sulfonated T-234 (ST-234), which is a mixture of EMI7.1 where M is an alkali metal or hydrogen, and the SO3 # M # group is para or ortho afford a surprising increase of stain resistance of nylon fiber and lightfastness of dye on nylon fiber. Example I. Synthesis of STP EMI8.1 A solution of 53.5 grams (0.238 mole) of Tinuvin-P in 650 milliliters of chlorobenzene was added to a 1 liter round bottom one-neck flask equipped with a magnetic stirrer and heating mantle and set up for reflux under an atmosphere of nitrogen. Then 15.85 milliliters (0.238 mole) of reagent grade chlorosulfonic acid was slowly added to the stirred solution over a period of approximately twenty minutes. The resulting mixture was brought to reflux and maintained at reflux for 1-QV hours. The solution was allowed to cool to room temperature under a slow stream of nitrogen. The contents of the flask were poured, with stirring, into a 2-liter beaker containing 300 grams of crushed ice. The resulting emulsion was neutralized to pH = 6.0 with 10 percent aqueous sodium carbonate solution. The solid product was filtered on a large Buchner funnel, using a medium speed filter paper. After several hours of air drying on the funnel, the resulting precipitate was washed with three 250-milliliter portions of toluene. The washed product was air-dried for ten hours. This nearly dry crude product was recrystallized from 4.5 liters of boiling water which had a pH = 5 (adjusted with sulfuric acid). The precipitate was allowed to settle at room temperature for 12 hours, then cooled to approximately 50C in a refrigerator for three hours. The resulting, finely divided, nearly colorless crystals were filtered on a coarse fritted glass funnel, and air dried for several hours. Actual yield of dry product was 51.6 grams, which is 71.2 percent of the theoretical yield. Example II. Synthesis of ST-234 EMI10.1 EMI11.1 A solution of 5 percent fuming sulfuric acid was prepared by adding 2.3 milliliters of 20 percent fuming sulfuric acid to 6.8 milliliters of concentrated sulfuric acid (0.0105 mole of SO3). Then 4.47 grams (0.0100 mole) of powdered Tinuvin-234 were slowly added to the vigorously stirred solution of fuming sulfuric acid which was maintained at a temperature below 250C. Most of the Tinuvin-234 went into solution. The small residue of undissolved solid was allowed to stir at room temperature for about one hour until complete dissolution. The yellow reaction mixture was quenched in 50 milliliters of ice water. The resultant mixture was neutralized to pH = 7 with saturated aqueous sodium carbonate solution. The resultant total volume was approximately 150 milliliters. This mixture was allowed to stand and settle for 12 hours. The precipitate was collected on a coarse glass fritted disc filter and washed three times with 20-milliliter portions of cold water. The precipitate was vacuum dried at SO0C for 12 hours. The weight of dried product is nearly the theoretical amount, but contains a small percentage of copretipitated sodium sulfate. This material was used to treat nylon for improved lightfastness without further purification. Example III. EMI13.1 Example IV. Photostability of UV Light Screens Dissolved in Polymer Film Matrices Light Screen Agent Polymer Destruction, % * Tinuvin P PMMA ** < 9 Tinuvin P Nylon-6 > 65 STP PMbE < 9 STP Nylon6 > 60 Tinuvin 234 PMMA < 7 Tinuvin 234 Nylon-6 < 5 ST-234 Nylon-6 < 5 * Twenty-one hours of irradiation in a Rayonet Photochemical Reactor equipped with RPR-3000 lamps at temperatures of 38 - 400C and ambient humidity. Amount of destruction determined by ultraviolet spectro photometry. ** Polymethylmethacrylate. This example demonstrates that hydroxybenzotriazoles lose photostability in a polyamide environment. It also demonstrates that incorporation of bulky hydrophobic groups near the intramolecular hydrogen bond (especially in the ortho position relative to the hydroxyl) effectively provides for a high degree of photostability. Typical Application Procedure Beakers containing from 0.5 to 2.0 percent (OWF) of STP or ST-234 or other soluble UV screen with a 20:1 liquid ratio and adjusted to the proper pH were heated to 710C in a water bath (water bath had equilibrated at 7l0C before adding "dye" beakers). Samples of nylon knitted sleeve were added (usually 1 or 2 samples, each weighing approximately 5 grams) and stirred constantly for 30 minutes. The sleeves were removed after 30 minutes and rinsed with distilled water. After rinsing, the sleeves were padded with paper towels to remove excess water. The damp sleeves were then placed in an oven (¯ 100 C) for one hour. The dried samples were then allowed to equilibrate under ambient conditions, in the dark for at least 12 hours before irradiation testing. Irradiation Samples were suspended in a Rayonet RPR-100 Photochemical Reactor manufactured by The Southern New England Ultraviolet Company. For all of the irradiation testing reported, the reactor was fitted with 16 RPR-3000 lamps. The major output of these lamps is centered at 300 nanometers, with a significant 254 nanometers component and small amounts of radiation of longer wavelengths. No attempts were made to filter the output or restrict exposure to a specific bandwidth. During all irradiations, the internal air circulation fan was operating. This resulted in operating temperatures of approximately 38 to 400C. No attempt was made to control humidity. The samples were suspended at the midpoint of the sources and rotated on a turntable to assure uniformity of irradiation. To further assure uniformity of exposure, the samples were rotated equally between direct front and back surface exposure. On longer term irradiations, the samples were cycled several times between ambient dark conditions and ambient irradiation conditions. Example V. Protective Effects of Water-Soluble UV Light Screens on Undyed Nylon-6 Knitted Sleeves Color Before Color After Additive* pH Uptake, % ** Irradiation Irradiation *** Control - - White Yellow STP 2 > 95 White Light Yellow ST-234 2 > 95 White Slightly Yellow STP 5 25 Light Yellow Yellow ST-234 5 35 White Slightly Yellow * Applied at 710C from 20:1 liquor ratio bath.. Nominally loading 0.1 - 2.0%. ** Percent bath exhaustion. *** Irradiation for 12 hours and for 40 hours in Rayonet Photochemical Reactor with RPR-3000 Lamps at 38 - 400C temperature and ambient humidity. This example illustrates that uptake and color of nylon sleeves treated with sulfonated UV light screens is vastly superior for application at pH = 2 relative to application at pH = 5. Also, the superior performance of ST 234 to STP is demonstrated. Example VI. Protective Effects of Water-Soluble UV Light Screens on Dyed* Nylon-6 Knitted Sleeves Color Before Color After Additive** pH Uptake,* *** Irradiation Irradiation**** Control - - Normal Severely Faded STP 2 > 95 Slightly Good Protection Off-Shade ST-234 2 > 95 Normal Excellent Protect ion STP 5 25 Off-Shade Good Protection Yellow Coloration ST-234 5 40 Normal Excellent Protection * Grey dyeing was with the following dyes at the following conditions. OWF, % (1) 0.0115 Tectilon Orange 3G (100% strength) (C.r. Acid Orange 156) 0.0121 Tectilon Red 2B (100% strength) tC.I. Acid Red 361) 0.0135 Telon Blue BRL (200* strength) (C.I. Acid Blue 234) (1) On weight of fabric) Dyeing Conditions: 1% Dowfax 2Al 2% monosodium phosphate pH 7 adj. w/trisodium phosphate Boil 30 minutes ** Applied at 710C from 20:1 liquor ratio, 0.1 - 2.08 (OWF) loading on non-DSR knitted sleeves. Similar results are obtained at room temperature. *** Percentage bath exhaustion, by spectrophotometric determination. **** After 12 hours irradiation in a Rayonet Photochemical Reactor with RPR-3000 lamps at temperatures of 38 400C and ambient humidity. This example demonstrates that UV screens which are sulfonated and which possess a bulky hydrophobic group near the intra-molecular H-bond (such as ST-234) may be effectively applied to dyed nylon sleeves and that such materials provide superior light screening capability compared to similar compounds without such a hydrophobic group (i.e., STP). BEST MODE The compounds useful for this invention can be applied as an attertreatment to dyed fibers, such as carpet face fibers, the preferred compounds are the ones labeled ST-234 above. In use a mixture of the mono- and disulfonated, both para and ortho isomers, are used. The compound may be applied in the aftertreatment either alone or in combination with other compounds, particularly those compounds which enhance stain resistance of the fibers, such as condensation product of formaldehyde with a diphenyl ether (hereinafter called FDE), and more fully disclosed in copending U.S. Serial No. 904.433 filed SePtember 8, 1987 The recommended aftertreatment conditions for ST-234 are: 0.1 to 0.5 percent on weight of fabric (OWF) concentration in the aftertreatment bath, pH 2.1 (with citric acid), bath temperature 1400F -(600C), liquor to goods ratio 25:1, fabric time in bath 20 minutes. Example VII. The mixture of compounds labeled ST-234 above was used in an aftertreatment bath to treat nylon carpet fiber previously dyed to a silver commercial carpet fiber color. Bath conditions were as set forth above except pH was 3.0, liquor to goods ratio was 30:1 and 0.47 percent (OWF) was applied. Lightfastness was improved over the control (no aftertreatment) to 1.45 A E from 4.12 AE for the control, or to an average Gray Scale rating of 3.5 at 120 SFU compared to control at 1.33 Gray Scale rating. Silver dyeing was with the following dyes at the following conditions. OWF, % (1) 0.0104 Tectilon Orange 3G (100% strength) (C.I. Acid Orange 156) 0.0054 Telon Red BRCL (250% strength) proprietary (Mobay) 0.0126 Telon Blue BRL (200% strength) (C.I. Acid Blue 324) (1) On weight of fabric Dyeing Conditions: 1% Dowfax 2A1 2% monosodium phosphate pH 7 adj. w/trisodium phosphate Boil 30 minutes Example VIII. (Staining Improvement) Using the recommended aftertreatment bath conditions given above, except temperature was 1100F (430C), the mixture of compounds labeled ST-234 above, or the compound labeled STP above, either alone or with the stain resistance enhancer FDE described above, were added to the aftertreatment bath for nylon carpet fiber in circular knitted sleeve form, predyed to the silver color described above. After treatment, stains were created with Cherry Kool Aid", containing FD & C 40 food coloring, by forcing about 5 cubic centimeters of Cherry Kool Aide into the fabric of the knitted sleeve of carpet fiber and blotting after five minutes. Results are given in the table below. Stain rating is on a 0 to 10 scale used by trained observers, unaware of which carpet fiber sample sleeve was treated with which compound. In the scale, low numbers mean good stain resistance and vice versa. Lightfastness Gray Scale* Stain Additive OWF, % 120 AFU 120 AFU Rating None (Control) 0 4.12 1.33 5 FDE/STP 2/0.5 2.52 3.67 0.75 FDE/ST-234 2/0.5 1.70 3.67 0.75 FDE 2 3.49 3.17 0.75 STP 0.5 2.47 3.17 3.5 ST-234 0.5 2.35 3.00 3.5 * Average, by AATCC 16E Thus, it can be seen that STP and ST-234 compound improved the stain resistance considerably over the control, but that best stain resistance is dependent on use of FDE, with or without STP or ST-234 compounds. However, the best overall combination of properties considering both lightfastness and stain resistance is the combination of FDE with ST-234 which had an # E rating of only 1.7, and average Gray Scale reading of 3.67. Low # E numbers and high Gray Scale numbers mean less fading.

Claims: WE CLAIM: 1. A sulfonated 2(2'-hydroxyaryl)-2H- benzotriazole selected from the group consisting of the following chemical structure EMI20.1 wherein R1, R2, R3 and R4 are independently the same or different alkyl groups and Z1 and Z2 are alkyl or sulfonated aryl group, provided at least Zl or Z2 is sulforrated aryl group. 2. A methoa for improving resistance to staining by anionic staining compounds and improving lightfastness of dyes on nylon fibers which comprises treating the fiber with an aqueous solution of sulfonated 2-(2'hydroxyaryl)-2H-benzotriazole at mild temperatures selected from the group consisting of EMI20.2 where R = tertiary alkyl or tertiary aralkyl, and 11 is a positive ion, EMI21.1 wherein R1, R2, R3 and R4 are independently the same or different alkyl groups and Z1 and Z2 are alkyl or sulfonated aryl group, provided at least Z1 or Z2 is sulfonated aryl group, and EMI21.2 where M is a positive ion, R is tertiary alkyl or tertiary aralkyl, and R5 is a short chain alkyl. 3. The method of claim 2 wherein said material is a fiber. 4. The method of claim 3 wherein said treatment is at a pH of between about 2 and 5. 5. The method of claim 2 wherein the temperature is between from about 30"C to about 900C. 6. The method of claim 4 wherein the temperature is between from about 300C to about 900C. 7. The method of claim 2 wherein the treatment is after dyeing of said fibers. 8. The method of claim 7 wherein said treatment is between about 10 and about 30 minutes in duration. 9. The method of claim 2 wherein the compounds I, III and IV are used to treat nylon materials other than fiber.

Inventors: HARRIS PAUL WESLEY, HOPF FREDERICK ROBERT, YARDLEY JAMES THOMAS, HARRIS, PAUL, WESLEY, HOPF, FREDERICK, ROBERT, YARDLEY, JAMES, THOMAS
Applicants: ALLIED CORP, ALLIED CORPORATION
Application year: 1987
Main classification: C07D249
IPC codes: C07D249, D06M13