US2775504A - Method of removing hair and wool from animal hides and skins - Google Patents

Method of removing hair and wool from animal hides and skins Download PDF

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Publication number
US2775504A
US2775504A US221115A US22111551A US2775504A US 2775504 A US2775504 A US 2775504A US 221115 A US221115 A US 221115A US 22111551 A US22111551 A US 22111551A US 2775504 A US2775504 A US 2775504A
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United States
Prior art keywords
skin
wool
composition
lime
calcium
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Expired - Lifetime
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US221115A
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English (en)
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Haskiel Zalcman
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Individual
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Individual
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Priority to US221115A priority Critical patent/US2775504A/en
Priority to GB8751/52A priority patent/GB706746A/en
Priority to FR1070436D priority patent/FR1070436A/fr
Priority to BE510678A priority patent/BE510678A/fr
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Publication of US2775504A publication Critical patent/US2775504A/en
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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
    • C14C1/00—Chemical treatment prior to tanning
    • C14C1/06—Facilitating unhairing, e.g. by painting, by liming

Definitions

  • This invention relates to the dehai'ring or removal. ofhair or wool frlom aniinal' skins. us'i'ngthe paintihgprocr ess wherein a paint composition is applied to the. flesh. side of theskinso that direct contact with thehair or wo'o'l is avoided'so far as is" practiable.
  • the invention is also particularly though not. excliisively concerned with the removal of wool from sheepskins.
  • Plumping also... has an. adverse effect on depil'ation. because .it con'strictsx the, opening, of the hair. or woolv follicle. so. that. even. though the root is sufiiciently loosenedit cannot be readily pulledunless the bulk ofthe root is. pulped'by more. drastic chemicaliaction.
  • The. object ofthe present invention isto achieve.satis.-' factory depilation at av pH so far. below theefiective minimum in the prior art asto reduce damageinlhepelt.
  • the paint composition preferably comprises calciumhydrosulphide (-Ca'('HS)2) andfllime (CaO) and water mixed in l proportion, the concentration of-calcium-hydro' sulphide. .(.Ca( HS-) 2-) being within the range of about 2%.-to-about 30%: and the concentration? of lime ((CaO) being-.withimthe. range ofabout 33%: to 'about "l'% each by" weight-oft. the: compositioni to' forrn a .paint.” of suitable concentration for. applicationvtoi the: skins; the consistency of the. fpainti being adjusted as necessary by the-addition: of. am inert' filler; The inert filler' may be;
  • The: inventioni relatesbasically to the method oidewooling; sheepskins -andrdehairing Iski'ns' whichhcomprise's applyingrto the flesh sideofirtheislins a paint cornposi tion compnisingca'lcium .hydrosulphid'e (Ca'(HS)2)' and lime- CaO.) and water'mixed rinsproportiong the; concen proved method iss'a composition conipris'iiig calcium hy-- drosulphide: (GatHSQa )E.-and:limei:(a0)' and water mixed in proportion the concentraisiontoti 'eal'cium' hydrosulphid'e (Ca(HS.).2) being within the range of a-bout.-3 to about" l0'%,.and.
  • the concentration o' f' lime (cao being within the composition to form a paint of suitable concentration for application to the skins the consistency of the painti bein g adjusted as necessary by the a'dditi'on ofan inemefillerii I-t 'will be untle'rstood th'atthe ihvention also provides the: method of-jde-woolin'g sheepskins and d'e-,
  • the period of depilation is lengthened a's-neeessary-- Patented Dec; 25 01 956 or hide to be treated.
  • Calcium hydrosulphide (Ca(HS)z) about 3% to about Lime (CaO) about 28% to about 4%.
  • Sheepskins vary as to thickness and fat content according to type as-well as condition and for a similar reason. Classified as to type according to the count of wool they carry skins carrying wool of higher counts are less thick and fatty than skins carrying wool of lower counts for the reason that fine wools are grown in drier areas than are coarse wools. But this variation is not very material in the case of skins carrying Wool of counts above 58 first because the variation is relatively slight and next because it is offset by the occurrence of folds in the skins of sheep carrying fine wools or what is described as a ribby condition in its skin. I
  • composition used in the above example was found by trial to be that most suited to the treatment of skins of the type (expressed in terms of wool count) of a 56-58 count and of average condition. Taking this composition as a norm the operator should increase the proportion of calcium hydrosulphide (Ca(HS)2) and decrease that oflime (CaO) Where the skins have the characteristic of a lesser thickness and fat content than a skin of 56-58 wool count of average condition whether that characteristic is due to variation in type or condition or both. Conversely, where the skins to be treated are characterized by greater thickness and fat content the operator should decrease the proportion of- -calcium hydrosulphide and increase that of lime.
  • Example 2 As an illustration of adjustments which shouldbe made, the example of a sheepskin of average condition and having a wool count of 50 may be quoted. A skin of this type and condition after being washed, soaked and deburred was painted with a paint containing About 3% calcium hydrosulphide (Ca(HS)2) About 25% lime (CaO) About71% water.
  • Ca(HS)2 calcium hydrosulphide
  • CaO calcium hydrosulphide
  • a salted calfskin of approximate. weight 5 lbs. green washed and soaked for about 12 hours and then fleshed and painted with a paint containing,
  • the skin was then dehaired in a skudding machine and it was found that the hair was in a good condition and the skin was in good condition.
  • the invention contemplates a composition substantially devoid of sources of monovalent metal ions, and comprising any suitable polyvalent metal source of hydroxyl ions, as hereinafter defined a suitable source of sulphide or hydrosulphide ions, and, where nec-' essary, a bufier material for controlling the hydroxyl ion concentration in the composition, so that the composition has a pH value of about 12 or less.
  • lime is obviously the most practical source of hydroxyl ions
  • other suitable bases such for example as barium hydrox ide (Ba(OH)2) or strontium hydroxide (Sr(OH)2) might" 7 also beused, and possibly also magnesium hydroxide )2)-
  • the hydrosulphide ion which must be present in suitable quantities to eifect depilation may be provided in various ways.
  • the most effective source is calcium hydrosulphide which should be in the proportion of 2 to in order to maintain the pH of the solution below about 12.
  • the hydrosulphide ions may be provided by passing hydrogen sulphide @S) into a slurry of lime in water, thereby forming a mixture of calcium hydrosulphide and unchanged lime.
  • the hydrogen sulphide could be passed into a slurry of lime and calcium sulphide, in which case the hydrogen sulphide would be absorbed and the pH of the solution lowered.
  • a calcium salt as a base for the hydrosulphide ion
  • other metal sulphides may be used so long as the metal is not monovalent and the metal sulphide is appreciablysoluble in lime water, or, if not soluble, then if the hydroxide of that metal is even more insoluble in water, so that the metal sulphide will act with calcium hydroxide to form calcium sulphide or hydrosulphide and an insoluble metal hydroxide.
  • sulphides of barium, strontium, magnesium, and aluminum may be used satisfactorily, although in some instances of high solubility a buffer material would have to be used in order to control the pH to below about 12, such bufier being a suitable acid or soluble calcium salt.
  • Calcium chloride or a soluble calcium salt may be used as a control by providing calcium ions which repress the solubility of the calcium hydroxide to thereby maintain the desired pH value of about 12 or less.
  • a suitable acid may be used provided such acid produces a calcium salt that is at least moderately soluble.
  • hydrochloric acid, acetic acid, hydrobromic acid, formic acid, lactic acid, nitric acid, nitrous acid, tartaric acid, and citric acid are common acids whose calcium salts are soluble, and which wouldnormally provide the soluble calcium salt needed to repress the solubility of calcium hydroxide.
  • lime .(CaO') found to achieve depilation within agiven period with the most favorable results as regards the skins and in the case of sheepskins the wool as well having regard'to the thickness and fat content of the skins; and, the expression inert filler means a finely divided substance the primary purpose of which'as an additive to the composition is to thicken the'consistency of the composition.
  • the method of effecting depilation to obtain high quality wool while preserving the quality of the skin which consists in applying to the flesh side of the skin an aqueous composition which is substantially free of sources of monovalent metal cations and which comprises calcium hydrosulphide and lime, the calcium hydrosulphide being about 3 to 7% and the lime about 25 to 14%, each by weight of the composition, the proportion of calcium hydrosulphide decreasing and of lime increasing within the above ranges with the increasing thickness and fat content of the skin, the composition having a pH of not more than 12 and not less than about 11.7, and the source of hydroxyl ions being suflicient in quantity to provide an undissolved reserve thereof suspended in the composition; allowing the composition to remain on the skin until the wool is loosened, and then pulling the loosened wool from the skin.
  • the method of effecting depilation to obtain high quality wool While preserving the quality of the skin which consists in applying to the flesh side of the skin an aqueous composition which is substantially free of sources of monovalent metal cations and which comprises calcium hydrosulphide and lime, the calcium hydrosulphide being about 3 to 7% and the lime about 25 to 14%, each by weight of the composition, the calcium hydrosulphide decreasing toward 3% and the lime increasing toward 25% to provide a lower ratio of calcium hydrosulphide to lime when the composition is applied to the neck and butt portions of the skin as compared with the ratio of calcium hydrosulphideand lime in the composition applied to other portions of the skin, whereby the proportion of calcium hydrosulphide decreases and of lime increases with the increasing thickness and fat content of the skin, the composition having a pH of not more than 12 and not less thanabout 11.7,-and the-source of hydroxyl ions being sufficient in quantity
  • the method of effecting depilation to obtain high quality wool while preserving the quality of the skin which consists in applying to the flesh side of the skin an aqueous composition which is substantially free of sources of monovalent metal cations and which comprises calcium hydrosulphide and lime, the calcium hydrosulphide being about 3 to 10% and the lime about 28to 4%, each by weight of the composition, the proportion of calcium hydrosulphide decreasing and of lime increasing within the above ranges with the increasing thickness and fat content of the skin, composition having a pH of not more than 12 and not less than about 11.6, and the source of hydroxyl ions being sufiicient in quantity to provide an-undissolved reserve thereof suspended in the composition; allowing the composition to remain on the skin until the wool is loosened, and then pulling the loosened wool from' the skin.
  • the calcium hydrosulphide and lime being about 3- to 10%andthe lime about28 to 4%, each'by weight of the-composition, the calcium hydrosulphide decreasing toward*3-% and the lime increasing'toward 28% to provide a lower-ratio of calcium hydrosulphide to'lim'e 9 when the composition is applied to the neck and butt portions of the skin as compared with the ratio of cal- 1 cium hydrosulphide and lime in the composition applied to other portions of the skin whereby the proportion of set forth in claim 1 in which the aqueous composition includes an inert filler in such quantity as to give the composition the consistency required for application and adherence to the flesh side of the skins.
  • the method of effecting depilation to obtain high quality wool while preserving the quality of the skin which consists in applying to the flesh side of the skin an aqueous composition which is substantially free of sources of monovalent metal cations and which comprises calcium hydrosulphide and lime, the calciumhydrosulphide being about 3% to 30% and the lime about 33% to 4%, each by weight of the composition, with the lime being at least 7% when the calcium hydrosulphide concentration is at about 3%, the proportion of calcium hydrosulphide decreasing and of lime increasing within the above ranges with the increasing thickness and fat content of the skin, the composition having a pH of not more than 12 and not less than about 9.9, and the source of hydroxyl ions being suflicient in quantity to provide an undissolved reserve thereof suspended in the composition; allowing the composition to remain on the skin until the wool is loosened, and then pulling the loosened wool from the skin.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Cosmetics (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Paints Or Removers (AREA)
US221115A 1949-10-18 1951-04-14 Method of removing hair and wool from animal hides and skins Expired - Lifetime US2775504A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US221115A US2775504A (en) 1949-10-18 1951-04-14 Method of removing hair and wool from animal hides and skins
GB8751/52A GB706746A (en) 1949-10-18 1952-04-04 Composition for and method of removing hair and wool from animal hides and skins
FR1070436D FR1070436A (fr) 1949-10-18 1952-04-11 Produits pour l'épilage des peaux
BE510678A BE510678A (enrdf_load_html_response) 1949-10-18 1952-04-15

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2775504X 1949-10-18
US221115A US2775504A (en) 1949-10-18 1951-04-14 Method of removing hair and wool from animal hides and skins

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US2775504A true US2775504A (en) 1956-12-25

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US (1) US2775504A (enrdf_load_html_response)
BE (1) BE510678A (enrdf_load_html_response)
FR (1) FR1070436A (enrdf_load_html_response)
GB (1) GB706746A (enrdf_load_html_response)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2937068A (en) * 1958-03-11 1960-05-17 William Amer Company Depilating predetermined areas in leather preparation
US2945737A (en) * 1957-04-25 1960-07-19 Tanners Council Of America Inc Method of dehairing hides
US3097912A (en) * 1959-03-30 1963-07-16 Booth Henry Hair and wool depilation method and composition

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1041897A (en) * 1911-12-18 1912-10-22 Albert H Stone Depilatory and process of making it.
US2169148A (en) * 1938-06-01 1939-08-08 American Cyanamid & Chem Corp Unhairing of hides and skins
US2487558A (en) * 1948-02-24 1949-11-08 Kamlet Jonas Cream depilatory and process for preparing same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1041897A (en) * 1911-12-18 1912-10-22 Albert H Stone Depilatory and process of making it.
US2169148A (en) * 1938-06-01 1939-08-08 American Cyanamid & Chem Corp Unhairing of hides and skins
US2487558A (en) * 1948-02-24 1949-11-08 Kamlet Jonas Cream depilatory and process for preparing same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2945737A (en) * 1957-04-25 1960-07-19 Tanners Council Of America Inc Method of dehairing hides
US2937068A (en) * 1958-03-11 1960-05-17 William Amer Company Depilating predetermined areas in leather preparation
US3097912A (en) * 1959-03-30 1963-07-16 Booth Henry Hair and wool depilation method and composition

Also Published As

Publication number Publication date
GB706746A (en) 1954-04-07
BE510678A (enrdf_load_html_response) 1953-10-23
FR1070436A (fr) 1954-07-26

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