Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C9/00—Impregnating leather for preserving, waterproofing, making resistant to heat or similar purposes
  • C14C9/02—Impregnating leather for preserving, waterproofing, making resistant to heat or similar purposes using fatty or oily materials, e.g. fat liquoring

Definitions

• the present invention is directed to synthetic fatliquors for leather treatment, having both reduced fogging characteristics and excellent light and heat fastness. Said fatliquors are particularly suitable for use in the treatment of vehicle upholstery leather.
• fogging means the condensation on the glass windows, and particularly on the windshield, of substances released by the interior outfit of the vehicle; fogging produces misting and hinders an unimpeded vision of the driver, especially in the darkness and when the driver is faced with lights of oncoming traffic.
• the substances condensed on the glass windows bind the dust and dirt particles brought through the fan into the vehicle interior, causing a further visibility impairment.
• vehicle upholstery leather exhibits low fogging characteristics.
• a piece of leather may be treated primarily to provide it with strength, its aesthetic qualities being of much less importance for its intended use.
• Treating hides and skins to form leather involves a number of interdependent chemical and mechanical operations and each of these operations has an effect on the final properties of the treated leather product, see Leather Facts, New England Tanners (1972).
• One important chemical operation in the treatment of leather is fatliquoring.
• Fatliquoring is used to impart the desired strength and temper properties to tanned leather.
• Faliquors lubricate the leather fibers so that after the leather is dried its fibers are capable of sliding over one another.
• faliquoring contributes greatly to the tensile and tear strength of the leather.
• Fatliquoring also affects the tightness of the break or crease pattern formed when the grain surface is bent inward, the objective being to produce a leather which leaves no or few fine wrinkles when bent.
• the basic ingredients used in conventional fatliquoring operations are water insoluble oils and fatty substances such as raw oils and sulfated and sulfited oils.
• weight percent of fatliquor oil on weight of leather ranges from 3 to 15 percent.
• Synthetic fatliquors are also known, such as esters of fatty acids having high molecular weight with alcohols or polyalcohols and the mono- and di-sulfosuccinates of fatty alcohols described in DE 1669347.
• the fogging characteristics of leather are normally measured according to the German standard method DIN 75201 which includes both a gravimetric and a reflectance tests.
• Some auto-makers have published their own fogging test procedures and have established their own fogging requirements. Some of these are reflectance tests, as for example Ford Motor Company, and some also incorporate gravimetric tests, such as Daimler-Benz.
• low fogging leather we mean a leather exhibiting low fogging characteristics when the fogging is measured according to DIN 75201; with the expression “low fogging fatliquor” we mean a fatliquor enabling to obtain a "low fogging leather”.
• the fatliquor of the invention may be in the form of an aqueous solution or emulsion.
• the active part of the fatliquor is in the form of an aqueous emulsion and it is present in an amount ranging from 30 to 90% by weight, preferably from 50 to 85% by weight.
• aqueous emulsions useful for the realization of the present invention optionally further contain water soluble organic solvents.
• It is another object of the present invention a method for treating the leather for vehicle upholstery characterized by applying to the leather in a fatliquoring step, an aqueous composition of one or more mono- or di-sulfosuccinates of ethoxylated and/or propoxylated fatty alcohols with a number of moles of oxide greater than 7, preferably greater than 10, the amount of the mono- or di-sulfosuccinates applied being between 5 and 25% by weight, preferably between 8 and 15 % by weight, referring to the weight of the leather at the wet-blue step, and the aqueous composition containing from 1 to 30% by weight of said mono- or di-sulfosuccinates.
• the aqueous composition contains from 3 to 10% by weight of one or more mono- or di-sulfosuccinates of ethoxylated and/or propoxylated alcohols.
• the fatliquors of the invention are easily obtainable in the form of an aqueous emulsion, by reacting maleic anhydride or maleic acid or fumaric acid with an ethoxylathed and/or propoxylated fatty alcohol, an then sulfiting the ester in water or in a hydro alcoholic mixture.
• aqueous emulsions can be directly used as fatliquors, according to the procedures well known by people skilled in the art.
• the aqueous emulsions are stable even without containing an emulsifying product.
• the aqueous emulsions of the present invention contain, as fatliquoring agent, only mono or di-sulfosuccinates of ethoxylated and/or propoxylated fatty alcohols with a number of moles of oxide greater than 7.
• said mono- or di-sulfosuccinates are compatible with other fatliquoring agents and can be used in mixture with them.
• the aqueous emulsions of the present invention can be used as fatliquors also for shoes and upholstery leathers.
• the fatliquors according to the invention are evaluated comparing both the fogging characteristics and the heat and light fastness of the leather treated with them or with other commercially available fatliquors.
• the fogging characteristics of the leather were measured according to the standard DIN 75201 both by the reflectance test and by the gravimetric test.
• the light fastness was measured according to the standard UNI 7639; the higher the value, the lower the yellowing and thus the better light fastness.
• the heat fastness was measured by treating a piece of leather at 80°C, for 72 hrs at 100% humidity; the evaluation was made by comparison with the "grey scale", according to standard ISO 105-A03; the higher the values the better the heat fastness.
• the Fatliquor 1 is prepared as described below.
• a reactor provided with both heating and cooling system, suitable stirring system and thermometer, is fed with 2840.5 g of 30 moles propoxylated, 3 moles ethoxylated cetyl stearyl alcohol.
• 2840.5 g 30 moles propoxylated, 3 moles ethoxylated cetyl stearyl alcohol.
• 135.6 g of maleic anhydride are added.
• the temperature is maintained at 100°C until the reaction mixture reaches an acidity number of 26(+/-2); then 450.2 g of hexylene glycol and 899.7 g of water are added, and the temperature is lowered to about 70 °C.
• 174 g of anhydrous sodium sulfite are then added in about 20 minutes, and the temperature is raised to about 90 °C.
• reaction mixture is stirred at this temperature for about 3 hours and then is cooled; a hydro glycolic solution (about 4500 g) is obtained, its dry fraction, mainly constituted of the sulfosuccinic monoester of 30 moles propoxylated, 3 moles ethoxylated cetyl stearyl alcohol, being 70% by weight.
• the wet blue cowhide is treated as described hereafter.
• the wet blue is given a thirty minute water wash, at 35 °C with 200% of water and 0.5% of Alkilarol NF (an anionic surfactant commercialized by Lamberti S.p.A.).
• Alkilarol NF an anionic surfactant commercialized by Lamberti S.p.A.
• the drum is drained.
• the drum is left in automatic rotation during the night.
• the mixture is then drummed (mixed) for 90 minutes.
• the drum is then drained.
• the drum is then drained.
• the drum is then drained.
• a piece of the bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case, the Fatliquor 1 is replaced by a fatliquor made of 65%wt of sulfited fish oil and 35%wt of water (Fatliquor 2).
• the fogging and the light and heat fastness are measured as above described.
• a piece of the bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case, the Fatliquor 1 is replaced by CORIPOL SMA/3 (Fatliquor 3), a low fogging fatliquor commercialized by TFL.
• the Fatliquor 1 is replaced by CORIPOL SMA/3 (Fatliquor 3), a low fogging fatliquor commercialized by TFL.
• the fogging and the light and heat fastness are measured as above described.
• a piece of the bovine leather is treated as described in Example 1 but omitting the fatliquoring step.
• the fogging and the light and heat fastness are measured as above described.
• Example Fatliquor Gravimetric fogging test (g/50cm 2 ) Reflectance fogging test (%) Light fastness Heat fastness 1 1 1,5 92,0 5 4/5 2 2 2,1 78,2 2 2 3 3 1,9 90,0 3 3 4 none 2,5 90,5 4 4/5
• Fatliquor 4 is prepared as described below.
• a reactor provided with both heating and cooling system, suitable stirring system and thermometer, is fed with 2923.5 g of 15 moles propoxylated cetyl stearyl alcohol. At a temperature of about 100 °C 251.5 g of maleic anhydride are added. The temperature is maintained at 100°C until the reaction mixture reaches an acidity number of 45(+/-2), then 875 g of water are added and the temperature is lowered to about 70 °C.
• reaction mixture is stirred at this temperature for about 3 hours and then is cooled; a hydro glycolic solution (about 4375 g) is obtained, its dry fraction, mainly constituted of the sulfosuccinic monoester of 15 moles propoxylated cetyl stearyl alcohol, being 70% by weight.
• a piece of the bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case, the Fatliquor 1 is replaced by Fatliquor 4.
• the fogging and the light and heat fastness are measured as above described.
• a piece of the bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case, the Fatliquor 1 is replaced by 65%wt of sulfited fish oil and 35%wt of water (Fatliquor 5).
• a piece of the bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case, the Fatliquor 1 is replaced by CORIPOL SMA/3 (Fatliquor 6), a low fogging fatliquor commercialized by TFL. The fogging and the light and heat fastness are measured as above described.
• the last piece of bovine leather is treated as described in Example 1 but omitting the fatliquoring step.
• the fogging and the light and heat fastness are measured as above described.
• Example Fatliquor Gravimetric fogging test (g/50cm 2 ) Reflectance fogging test (%) Light fastness Heat fastness 5 4 0,6 94,5 5 4/5 6 5 1,5 90,0 3 2 7 6 1,0 93,0 4 3 8 None 1,2 93,0 4 4/5
• a piece of bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case Fatliquor 1 is replaced by Fatliquor 4.
• the fogging is measured as above described.
• a piece of bovine leather is treated as described in Example 1 (using in the fatliquoring step Fatliquor 1).
• the fogging is measured as above described.
• a piece of bovine leather is treated as described in Example 1 except for the fatliquoring step: in this case, the Fatliquor 1 is replaced by 80%wt of the sulfosuccinic monoester of 6 moles propoxylated cetyl stearyl alcohol and 20% of water (Fatliquor 7).
• the fogging is measured as above described.
• a piece of bovine leather is treated as described in Example 1 but omitting the fatliquoring step.
• the fogging is measured as above described.
• Example Fatliquor Gravimetric fogging test (g/50cm 2 ) Reflectance fogging test (%) 9 4 0,45 99,7 10 1 0,55 93,2 11 7 0,75 89,8 12 None 0,40 98,8

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)
• Lubricants (AREA)

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Cited By (4)

Citations (4)

• 2001
  • 2001-12-17 IT ITVA20010046 patent/ITVA20010046A1/it unknown
• 2002
  • 2002-12-10 EP EP02027455A patent/EP1319723A1/de not_active Withdrawn

Patent Citations (4)

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