US2582086A - Composition for carroting fur and the like - Google Patents

Description

Patented Jan. 8, 1952 TNT OFFICE COMPOSITION FOR GARROTINGFUR AND THE LIKE I .B cm Tu k ni a a g and R m n 'lj mnerthltwtcwn, 3011111., assignors to The HJ- 1 9 firmwar- Danburir, 1

No Drawing, Application December 23, 19.49,

,Sei'ialNo.134.860

.5 Glaims. (o1. s-,1 1 2;

Our invention relates to the treatment of fur and similar animal fibers to improve the felting qualities, otherwise shown as car-roting, and more particularly to a composition of matter adapted to be employed in such treatment.

To produce a material such as felt from fur and the like, it is first necessary to treat the fur to promote ease and rapidity of felting, and to acquire a high strength product. A preliminary chemical treatment, known as carroting, is-generally used, and it involves applying a relatively strong oxidizing and/or hydrolyz ing aqueous solution to the fur before it is sheared from the skin. The solution may be applied by any suitable means, as by brushing, and the pelts are either air-dried or 'ovensdried before shearing. The. fur .is then graded, blended, and, by a process of treatment with hot water and pressure applications, is formed into a felt whereby fibers become tightly interlocked and compactly associated with one another.

The chemical reagents have the faculty of rendering this process of .felting more thorough and efficient, the mechanics of which have never been explained satisfactorily. Nevertheless, perhaps the most successful carrot is an acid solu tion of a mercury salt, but being toxic it may not be used because of its harm to the workmen. Consequently, many substitutes have been developed, and these generally are strong solutions 5 of oxidizing and hydrolyzing reagents such as mineral acids, organic'acids, salts of these acids. peroxides, and the like. A carroting solution by its very nature damages the fur, and so the problem in selecting any composition ,for. this purpose is to provide sufiici'ent treatment foisuccessful felting without at the same time dcstroying the strength of the fibers. Accordingly, a common difiiculty arises from the use of these mercury carrot substitutes because they ordinarily must be relatively strong to render the fur feltable, with the result that fibers are inordi-' nately damaged. Indeed these substitutes have a high specific gravity, normally above 6 Baum, and generally about 8 Baum.

It is accordingly among the objects of our in vention to provide a carrotlng solution which renders fur felta ble without deleteriously altering the strength and wearing qualities of the final product. A further obi ct is to provide a successful and practical carroting solution with a low specific gravity, for example, in the range of 3 5"- Baum. Anoth'er ob ect is to use a'carrot-ing solu- 'tion composed 'of inexpensive reagents whereevery possible, and to employ only small percentages of expensive ingredients so that theLcos-t oi carroting is maintained within commercially ac: ceptable limits. A still further object is to provide a carroting solutionwhichis not toxic under ordinary conditions of its use.

Various changes in and departures from the embodiment of our carroting composition may made as the same is -hereinaf;ter exemplified, all within the scope of our generic invention, it being understood that the matter ,set iorth. is submitted as illustrative and not in a limiting sense.

Our new and improved composition is aqueous solution 9. reagents which are well known for their oxidizing and/or hydroly zing characteristics, but which are combined in such proportions and with certain other ingredients that a far weaker solution than hitherto-thought possible can be used to carrot fur for successful ltin solution does not unduly damage the fur so that strong, high quality felt is produced.

The preferred embodiment of our carroting solution contains .a small percentage of one -.,or more strong or moderately strong acids, ssuchxas hydrochloric and nitric, together with .an oxis dizing agent such as hydrogen peroxide, and a small amount of ethyl alcohol, to produce a solution with aspecific gravity in the order of 3-'5 Baum. Such weak solutions are incapable of carroting the fur within practical limits, but we have discovered that the addition of a small amount of either phosphotungstic acid or phosphomolybdic acid renders them highly satisfactory for this purpose.

This preferred solution contains nitric acid in the order of 1- 3%'together with 04.5% hydrochloric acid, though nitric acid may he used alone with equivalent results. These proportions are computed as percentages of HNQs and H01, respectively. in the entire weight of liquid. In addition to the acid, a small. amount .of strong oxidizing agent, such as. 343% by weight oi hydrogen peroxideis used (computed. as H209, together with 0.3 1% by weight of ethyl alcohol (computed as Cal-IsOI-I). The specific grav ity of the final mixture is about '3 Baum. Carroting with this solution is not successful, but when -0.1 -0.4% by 'weight of either phosphotungstic acid or phosphomolybdic acid or a combination of the two is added, a high strength, good quality felt can be produced. The specific ravity of the-final tsolutionispreferably within Being relatively week. however, the

the range'of 3-5 Baum. and consequently little damage to the fur is encountered as with other known solutions ranging from 6-8 Baum and upwards;

Considering the infinitesimal amounts of the phospho'tun'gstic or phosphomolybdic acids which are employed, his most probable that a-catalytic action is encountered, whereby the reagents are utilized more efficiently. The weak solution in itself is not satisfactory and therefore it would seem that such a small proportion of the phos;-- photungstic and phosphomolybdic acids would desire to be restricted in our invention to any particular theory, it being sufiicient that the" result herein described is accomplished.

Several tests have been conducted to determine composition limits and substitutes for our preferred carroting solution. Considering the acids, those which are strong or moderately strong are the most useful; andtheir content should be kept quite low, commensurate with good results, and indeed it shouldnever be necessary to use over 4.5% by weight. Highlysatisfactory carrots are obtained by the use of the combination of nitric acid and hydrochloric acid, or of nitric acid alone; however hydrochloric acid by itself appears inferior.

The strongoxidizing agent, hydrogen peroxide, supplements the action of the acid in treating the animal fibers,'but its concentration is maintained within the limits of 35% to avoid undue damage which weakens the final felt. I I

' A' small amount of organic solvent, such as ethyl alcohol, is beneficial in causing the fibers to wet more readily, and its cleansing properties are generally thought to cause more uniformity of treatment. V v

Since the carroting reaction by its very nature causes damage to fur fibers, the primary object in developing any satisfactory composition for this purpose is to balance the adverse factors so that the best combination of quality and strength of felt is obtained. OfttiineS a good quality felt, as judged by the feel, may be produced from fur whichis rather severely damaged, but the final product will have poor wearing properties and will prove to be weak when judged by certain physical tests such as tensile strength and flexing value determinations. Conversely, when damage is avoided it is impossible to obtain a good, strong, tight felt. Either the felting rate is so slow that an appreciable quantity of fur is .lost while felting, or felting stops before final size is reached, after which further work merely increases the size of the hat body.,

The limits of (LL-0.4% for phosphotungstic or phosphomolybdic acids are critical in providing the optimum combination of strong, good quality felt, 7 These were determined by preparing a series of basic carroting solutions containing 1.54% HNQ3, 0.' 73% HCl, 0.4 C2H5OH, 3.3% H202 and phosphgtungstic acid varying in amounts from to 1.6%. These various solutions were then used to carrot rabbit fur, and felt hats were made by usual commercial practice. I The flexing test is perhaps the most significant physical test for evaluating damageto fur felt, whether resulting from carroting'or subsequent manufacturing processes such 'as'dyein'g. A flexing' machine "is commercially-available for this 4 test, and its use on fur felt hats is well known in the art. In this test a sample of felt one-half inch wide and six inches long is held in a flexing machine under tension of two and one-half pounds and is subjected to repeated-bendings at 'the rate of 110 flexes perfminute until it breaks.

The flex value is the average number'of flexes required to break eight samples cut from different portions of the hat so that all sections thereof ma e tested-;.

Aifelt made from fur carroted with the basic solution withoutany. phosphotungstic acid has a highflex value because the solution is weak and-doeslit'tle damage. As mentioned above, this basic solution comprises 1.54% 'HNOa, 0.73%

H01, 0.4% C2H5QH and 3.3% H202, balance water.

' However, the felt is loose and soft as judged by its feeL-and the time and number of operations relower-as the amount ofphosphotungstic acid in the carroting solution is increased, and when 0.4% is exceeded the quality and felting rates are erratic and the felts are of such poor strength I as not to be useful commercially. Consequent- '1y,.th e practicalrange is between 0.1414 phos photungstic acid in the'carroting solution hav ing a specific gravity of only 3-5 Baum. Phosphomolybdic acid may be substituted in like amounts to obtain equivalent results.

The phosphotungstic acid employed in the above-tests hasthe formula P2O5.24WO3.44H2O. and the phosphomolybdic acid has the formula 20MoOa.2IrhPO4.48I-I2O. v

The cost of these acids is very high and fo commercial use. it is usually advisable to limit its concentration to about 0.2%, since the results appear equally satisfactory throughout the recommended range. V Q

As many possible embodiments may be made of the above invention and as many changes might be madein the composition above set forth, it is to be understood that all matter hereinbefore set forth is tobe interpreted as illustrative and not in a limiting sense What is'claimed is:

1. As a composition of matter for the carroting of fur or the like, an aqueous carroting solution containing. a non-hydrolyzing oxidizing agent, a volatile hydrolyzing acid, and an acid of the group consistingrof phosphotungsticacid and phosphomolybdic .acid as a catalyst, said solution having the proportions of 1.0-4.5% by weight said hydrolyzing acid, 375% by weight said oxidizing agent, and. 0.l-.0.4%.by weight of said latter acid or acids, l i

v2. An aqueouscarroting solution for treating fur. and the like containing3-5.% byweight hydrogen peroxide, 1-3% by weight nitric acid, and as a catalyst 0.l-0.l% -by weight phosphotungstic acid, the specific ,gravity of said solution being between 3-5" Baum.

3. An aqueous-carroting solution for treating fur and the likecontaining 3-5% by weight hydrogen peroxide, 1-3% by Weight nitric acid,- and as acatalyst '0.1-0-.4% by 'weightphosphomolybdic acidpthe specific gravity of said solution being between 3-5" Baum.

4. Anaqueous vcarroti-ng solution fortreating fur and theiikecontaining 1-3 by weight nitric acid,- hydrochloric 'acid'-not'-to exceed 1.5% by weight; 35%- by: weight-hydrogen peroxide; as a ata yst- 0,141 ab! weieht-.-p osp tunsst c acid, and 0.3-1.0% by weight ethyl alcohol, the specific gravity of said solution being between 3-5" Baum.

5. An aqueous carroting solution for treating fur and the like, containing 3-5% by weight hydrogen peroxide, 1-3% by weight nitric acid, 0.3-1 by Weight ethyl alcohol, and as a catalyst 0.1-0.4% by weight phosphotungstic acid, the specific gravity of said solution being between 3-5 Baum.

The following references are of record in the file of this patent:

6 UNITED STATES PATENTS Number Name Date 1,710,565 Bohm Apr. 23, 1929 2,048,645 Fabian July 21, 1936 2,087,854 Fabian 1 July 20, 1937 2,169,997 Fabian Aug. 22, 1939 2,181,884 Giuliano Dec. 5, 1939 2,242,668 Dolid May 20, 1941 2,330,813 Donner Oct. 5, 1943 2,411,725 Hodshon et a1. Nov. 26, 1946 FOREIGN PATENTS Number Countiy Date 323,944 Great Britain Jan. 16, 1930 441,619 Canada 1947 (Through J Am. Leather Chem. Assn., Nov. 1947.

page 588) 803,872 France Oct. 10, 1936

Claims (1)

1. AS A COMPOSITION OF MATTER FOR THE CARROTING OF FUR OR THE LIKE, AN AQUEOUS CARROTING SOLUTION CONTAINING A NON-HYDROLYZING OXIDIZING AGENT, A VOLATILE HYDROLYZING ACID, AND AN ACID OF THE GROUP CONSISTING OF PHOSPHOTUNGSTIC ACID AND PHOSPHOMOLYBDIC ACID AS A CATALYST, SAID SOLUTION HAVING THE PROPORTIONS OF 1.0-4.5% BY WEIGHTT SAID HYDROLYZING ACID, 3-5% BY WEIGHT SAID OXIDIZING AGENT, AND 0.1-4% BY WIEGHT OF SAID LATTER ACID OR ACIDS.