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
  • C14C3/00—Tanning; Compositions for tanning
  • C14C3/02—Chemical tanning
  • C14C3/04—Mineral tanning
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47H—FURNISHINGS FOR WINDOWS OR DOORS
  • A47H1/00—Curtain suspension devices
  • A47H1/10—Means for mounting curtain rods or rails
  • A47H1/14—Brackets for supporting rods or rails
  • A47H1/142—Brackets for supporting rods or rails for supporting rods

Definitions

• This invention relates to the tanning of hides and skins and has among other objects the improvement of the method of tanning with a solution of a soluble pyrophosphate and alum whereby a product of uniformly high quality is assured, and the process is maintained at a high standard efficiency.
• Soluble pyrophosphates have been here-- tofore su gested as tanning agents in Letters Patent #1,039,150 and #l, l9l,527.wherein a process is described for the employment of solution of pyrophosphate of sodium with alum and salt.
• the hides are subjected to the action of such a solution after the usual preliminary cleansing and unhaii'in treatment. and under certain sneci fied conditions, to deposit aluminum pyrophosphate in the interstices of the hide substance.
• the process described has attained a wide commercial importance because of the high quality of the product, the
• the range of temperature which I find to be best adapted for the practical operation of the process lies between approximately 90 F. and 107 F., the latter temperature marking the danger pointer extreme upper limit at which deterioration of the product commences, if the materials are permitted to attain such a temperature for any considerable period.
• the range of temperature is maintained between 95 F. and 105 F, the product resulting from the process, when carried out within this range,
• the hides are preferably subjected to the usual washing, liming, unhairing, and tleshing operations.
• the hides are then. preferably bated and finally washed in water or suitable cleaning solutions, until thoroughly clean and in suitable condition for the actual tanning operations.
• the details of the preliminary treat ment may be widely varied and may follow the established practice of tanyards or depart therefrom in various respects, the preliminary treatment forming no part of my present invention.
• the thoroughly cleaned hides are then subjected in a suitable receptacle, for example, a pit, drum, wheel, or paddle, to the action of the tanning solution which includes a suitable proportion of a soluble pyrophosphate, a soluble aluminum. salt and a suitable material such as sodium chloride or common salt, for overcoming the astringent action of the aluminum salt upon the hide whereby it is maintained in porous condition v to assimilate the active tanning agents.
• a suitable receptacle for example, a pit, drum, wheel, or paddle
• the tanning solution which includes a suitable proportion of a soluble pyrophosphate, a soluble aluminum. salt and a suitable material such as sodium chloride or common salt, for overcoming the astringent action of the aluminum salt upon the hide whereby it is maintained in porous condition v to assimilate the active tanning agents.
• a suitable receptacle for example, a pit, drum, wheel, or paddle
• sodium pyrophosphate
• ammonia alum, and common salt are em ployed although other available soluble pyrophosphates may be substituted, and any soluble aluminum salt may be advan'tageously used.
• soda alum, potash alum, aluininum'sulphate, or aluminum chloride- may be substituted for the-ammonia alum.
• the Concentration of the solution with reference to the several'salts may vary somewhat depending upon the particular character of the-hide treated; Preferably, the relative quantity of the pyrophosphat'eto the alum is maintained at the lowest ratio compatible with the successful accomplishment of thedesir'edobject.r Ihave discovered that. depending'upon the particular character of the hide treated, the ratio of pyrophosphate t'o thealum mayyary, from 1:4 to 1:10, the higher proportions of pyrophosphate being desirable where the hides are heavy and close in texture, and'the lower proportions being desirable in the treatment of skins andhides joffloose texture and relativelylight weight.
• the range of relative proportions of pyrophosphate to alum may be limited so that; the alum exceeds 5 but doesnot exceed 7 times the'weight of the pyrophosphate.
• I refer to thecrystallized alum containing 24 molecules of water of crystallization, and
• the water content of which may vary between 20 and/l0 per cent of the veiglit of the hide substance treated.
• the temperature is undercontrolthroughout the operation, a suitably arranged thermometer giving a continuous indication of the term perature.
• the process is carried out'in a wheel or drum the temperature may be reduced'at intervals when necessary by stopping rotation of the wheel or drum and opening thedoor. or closure thereof. contents of "the drum or' wheel thus remain quiescent for a period'sufficient to reduce the temperature as deslred after whichthesprocess is continued with alternateexposure of the contents to reduce the temperature as may-be necessary to maintain it below the maximum of 107 F.
• the temperature ijsfniever allowed to rise above 105 F., the best results being obtained when the range Cramps-t.
• tide is between 95 F. and 105
• the liquor iswithdrawn and the hides are subjected'to any of the usual finishing operations.
• the hides may be subjected to the action of a solution containing a suitable coloring agent, preferably containing 'a tannin.
• My present invention is directed solely to the limitation of. the temperature substantially throughout the tanning operation, whereby the rise in temperature above 107FQ is positively prevented.- This Ihave found to result in the production "of leather of uniform quality, regardless of the varia tion of other factors affecting the process.
• Such factors may be widely varied in applying the process to hides and skins of different quality andcharacter to produce commercial leather, so long as thetempera tufre'is prevented from exceeding the"maXimum hereinbefore specified substantially hroughout the tanning operation.
• tanning agents to the hides or skins, so long as the temperature is maintained and prevented from exceeding the range as specified in the auneiied claims.
• A. method of tanning hides and skins which includes drumming the hides in a solution containing asdluble aluminum salt and a soluble pyrop hosphate and stopping the drumming opera-tlon'atintervals whereby th t fatui eof the mass is limited not to exceed 107F. 1 i

Landscapes

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

Priority Applications (3)

Applications Claiming Priority (3)

Publications (1)

Family

ID=60411605

Family Applications (1)

Country Status (3)

• 1916
  • 1916-02-10 FR FR480917A patent/FR480917A/fr not_active Expired
  • 1916-11-18 DE DE1916330858D patent/DE330858C/de not_active Expired
• 1919
  • 1919-02-11 US US276339A patent/US1427221A/en not_active Expired - Lifetime

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