US2169997A - Process of carroting fur and the like and composition therefor - Google Patents

Description

r so Patented Aug. 22, 1939 UNITED STATES PROCESS OF CARROTING FUR- AND THE LIKE AND COMPOSITION THEREFOR Constantine F. Fabian, Brookfield, Conn., assignor to The Non-Mercuric CarrotCompany, Danbury, C0nn., a corporation of Connecticut No 1/)tawing.

12 Claims.

This invention relates to carroting processes for fur and the like, employed to give such fur felting properties, particularly for use in hat manufacture.

r In the case of prior carroting processes, it has been the usual practice to brush the carroting solution on the fur while the latter is still on the skins, allow it to dry, then either place the skins in piles or stacks or cut the fur and store the cut fur, and then allow the carroted fur to remain in that stored state for days, weeks or even months, during which time the carroting compound effects a "working in" so that its full effects are secured. That is to say, such proc- I esses rely in large part on the continued efiect of the carroting after the solution has been applied and dried and during the period that the fur is aging or in storage.

For such agingaction of the carrot, carroting solutions have heretofore included as active agents non-volatile compounds, such as nonvolatile acids, metal catalysts non-volatile salts or non-volatile oxidizers. Thus, in the use of the common nitric acid and mercuric nitrate solution, where the nitric acid is used in relatively low concentration the mercuric nitrate is relied on to prolong and complete the carroting during the aging. When non-volatile, sulphuric acid is employed as the hydrolyzing agent, the acid acts as a factor in completing the carroting effectduring aging, and in such case it has been foundnecessary to prevent destructive action by the acid on the fur during the storage of the latter by the presence of compounds which have an inhibiting effect, such as neutral salts of a strong base and a strong acid.

One objection to the heretofore generally prevalent use of the-mercuric nitrate-nitric acid solution is the noxious effect arising from the use of mercury which, as is well knowri, is deleterious to and endangers the health of the worker's, both those performing the carroting and those engaged in the subsequent steps of hat manufacture.

Another objection to carroting processes as heretofore employed, making use of non-volatile carroting agents, has beenthe fact that they result in deposits on the fur of metal salts or other non-volatile substances which add initially to the weight of the fur, but, due to their water solubility, these substances are removed in the subsequent washing and other processing of the hats. Accordingly, when the carroted fur is weighed to assign a definite weight to the individual hat body preparatory to its formation, a false result is reached since the subsequently Application November 8, 1938, Serial No. 239,510

formed and processed hat body ilosesxweight in fore, with the use of carroting solutions containing such non-volatile, water-soluble ingredil0 ents results in-a fur of non-uniform weightawhich adds further to the difficulty in securing the finally formed hat bodies of the" intended weight. Furthermore, it is well known that without the aging heretofore referred to; fur *carroted. by 15 processes heretofore employed is found to have inadequate felting properties, and such prior processes andcarroting compositions have been incapable of adequately carroting fur which is required to be used soon after the application of the carroting solution and without aging, or storage and which is known as green fur.

One object of the present invention is to produce adequate felting properties in..-the carroted 1 fur, including rapidity in felting, tightness of the felt, and a smooth, firm body in the felted fur.

Another object is to avoid the use of mercury or other metallic compounds harmful, to the health of the workers. 4

Another object of the invention is to secure the intended weight for hats formed from the carroted fur, through the avoidance of the deposit on the fur of metal salts or other non-volatile substances. r

Another object is to make use of a carroting solution substantially free from non-volatile carroting agents and of a concentration carefully selected to provide the optimum condition of carroting effectiveness. Due to the volatility of the solution, this permits the continuance of the 4.0 same ideal or optimum carroting effect during the entire carroting treatment, including both the stage of brushing and the stage of drying. By this means superior felting properties are imparted to the fur since the latter is treated without the necessity of a prolonged stage of aging or storage, which is necessary Where non-volatile compounds are employed. In the latter case, during' such prolonged stage of drying, the activity and effectiveness of the carrotingegents are employing a volatile carroting solution, substantially free from metal salts or other non-volatile carroting agentsjand particularly free from mercury and-the noxious conditions surrounding its use.

In hat manufacture the effectiveness and commercial availability of any carroting solution is dependent in large measure on the rapidity with which the shrinking can be performed in its several stages after the hat body is formed in the first instance from the oarroted fur.

In hat manufacture as now carried on, the shrinking process commonly includes three principal stages-first a so-called wetting down or starting, next a more vigorous shrinking, and, as a last stage, and usually after the partly shrunk'bodies have been dyed, shrinking to final size-and firmness. Each stage of shrinking is commonly carried out in whole or in part on a machine in which the hat body is subjected to a kneading action and to the simultaneous application of hot water.

The time consumed in each stage of shrinking is, highly important, not only because a certain rate of output is commercially essential, but because, with properly carroted fur, a more acceptable felt is produced by relatively rapid shrinking, and, in the third stage of shrinking, if the timed shrinking is prolonged, the dye-in affected. A certain maximum time period therefore in which the shrinking must be performed in each-stage is recognized as essential in the case of any commercially operative or usable carroting process.

In the case of the common mercuric nitratenitric acid solution, relatively low acid concentrations and of a relatively narrow range must be employed to bring the shrinking for each of the-shrinking stages mentioned within the commercially permissible time. Such time, for example, is exceeded unless the concentration of nitric acid is at least approximately 2 70 by weight, but if the acid concentration exceeds ap proximately 6% such time is again exceeded, the optimum result being reached with a concentration of approximately from 4 to 5%. With concentrations increased above 6%, the time required for shrinking is increased at a rapidly accelerated rate, so that the use of aconcentration of nitric acid of even '7 or 8% is inoperative from a practicalv or commercial standpoint. This is true whether or not the solution is used in the "presence of an oxidizer, such as hydrogen peroxide.

I have found that by employing a volatile hydrolyzing acid, such as nitric acid, in high concentration, and a concentration higher than that used or practically usable in the mercuric nitratenitric acid solution, and by utilizing in the presence of such high concentration of acid a 'volatile oxidizer. such as hydrogen peroxide, an efl'ective carroting solution may be had free from mercury and its essential objectionable features and capable of a more rapid shrinking in each of the several stages of shrinking than can be obtained from the usual mercury carrot.

Any volatile acid having a hydrolyzing action may be employed, such as nitric acid. acctic acid. formic acid, hydrofluoric acid in solution, etc. These acids, howevenshould be employed in relatively high concentrations. For example, in the case of nitric acid technical acid of approximate ly 63% concentration), which is preferable for considerations of expense, convenience and availability, concentrations are employed having a wide range of from approximately 11 or 12% to approximately 20% by weight, within which range thcshrinking at each of the three stages is effected within the commercially permissible time period.

Using concentrations within the range indicated, an optimum carroted effect may be had which reduces the time required for shrinking at each of the three stages of shrinking to substantially less-than the shortest time required for acid.

A probable explanation of the effectiveness of this carroting solution is as follows:

Animal fiber is an amphoteric substance of colloidal nature having basic and acidic functions which may be brought into action only by means of strong bases or strong acids respectively. At the isoelectricpoint, or state of electrical neutrality, the amino groups and carboxyl groups of the molecules of these amphoteric substances have interacted to formwhat may be termed as inner salt which, if undisturbed, remains intact, forming double ionized molecules. To split these molecules and bring them into a state of maximum chemical activity appears to be an important function of the carroting treatment.

I have found that the condition of maximum chemical activity for these molecules is reached by the use of an acid having a pH value ranging from 1.4 to 0.8 lacid'cresol red as indicator), or by the use of an alkali having a pH value of approximately 11 La Motte purple as indicator). At all events, under either of these conditions the fur acquires the most desirable carroting properties.

Treatment, however, with an alkali is undesirable due to side reactions and the destruction or impairment of the fur fiber. But, by treatment with an acid having a hydrogen ion concentration represented by a range of pH 1.4 to pH 0.8 (or one corresponding to a concentration of from approximately 11 or 12% to 20% of technical nitric acid at normal or room temperature) and employing a volatile acid in solution free frogn non-volatile compounds, not only is a pH value furnished in the'first instance which is ideal for building up the electrical activity of the fur molecules, but such ideal value is maintained at every stage of the carroting treatment, i. 0., the stage of brushing and the stage of drying.

On the other hand, in the case of a solution including non-volatile carroting agents. the pH value of the acid hydrolyzcr is constantly undergoing a change during the drying of the fur, and the pH valuc. if at any time the ideal 'onc, remains so but for a short interval.

If other volatiliacids such as [11050 mentioned are employed. the concenlrniion should be such as to llLlVlsubstantially the same hi'drogcnion concentration as the ('oncmlll'utinn ol lllil'lt' acid above mentioned to ive tlurequir d h,\'drolyzing cl'l'rcl in lhcir action on LllllDl'lOitl'h' substances.

such as proteins. That is to say, a minimum concentration of such acids should be used. which is represented by pH 1.2, which corresponds to a concentration of approximately 12% by weight have a minimum concentration of approximately vbe employed for the oxidizer.-

" 44%. If formic acid (technical 90%) is used, it

should have a minimum concentration of approximately 38%.

A relatively wide range of concentration may In the case of hydrogen peroxide it is preferably used in the order of from 4 to 8% by weight. Hydrogen peroxide is preferably employed as the volatile oxi-.

dizer due to its availability, oxidizing effect, and

dizers may be employed. Among organic peroxides, for example, there may be used perox or peroxides obtained by reaction between aldehydes and hydrogen peroxide in ether. On the other hand, organic peracids may be employed of the type RCOzH such as CHiCOiH.

Where hydrogen peroxide is employed, a small quantity of some stabilizer is preferablyused. In the presence of dust and small metal particles which areapt to be deposited on the fur during the processing of the skins prior to carroting, hydrogen peroxide rapidly decomposes, resulting in inadequate and non-uniform oxidation of the fibers. To prevent such decomposition, a minute quantity of some stabilizing substance, such'as urea, citric acid, sodium metaphosphate, sodium salicylate, etc., should be employed, these substances being inactive, without carroting effect, and added for the sole purpose of stabilizing the hydrogen peroxide.

The volatile acid and the volatile oxidizer ould preferably be selected so that they are zr i capable of reacting one on the other. For isrample, it is inadvisable to use such compounds chloric acid or perchloric acid for oxidizers which'produce free chlorine, the latter resulting in chlorination of the natural fibers and the weakening thereof.

A carroting solution prepared as herein de scribed may be brushed on the fur at normal or room temperature and acts promptly following its application to the fur, giving the required carroting effect before it has disappeared through volatilization, leaving no free acids nor oxidizers which must be relied upon to prolong the carroting efiect, leaving no other non-volatile, water-soluble substances on the fur, and requiring no storage nor aging of the fur to complete the carroting.

The application of the carroting solution to the animal fibers may be made by brushing or spraying the carroting solution on the fur while the latter is still on the skins, or cut fur may also be carroted.

The invention will be best understood by the following specific examples of carroting solutions which may be prepared according to the general principle of the invention and intended each, for

application to the animal fibers while still on the skins. In each of the examples, the carroting composition comprises an aqueous solution consisting of i100 parts by weight of the, final solution and including in it the following substances, in the proportions specified. The nitric acid is assumed to :be technical acid approxidrogen peroxide by weight) 1 Example 1 j/ 'Partsby y weight Nitric acid 1 5 Hydrogen peroxide "20 W Example '2 Nitricacid 15 Hydrogen peroxide; e s 17 Sodium salicylate 0.05

' 4 Example 3' I Nitric acid y 12 Hydrogen peroxide r 17 Urea 0.05 Citric acid 0105 WWW Acetic acid (technical 56%) Hydrogen peroxides--. i'17 Sodium metaphosphate 0.005 Sodium salicylate"; 0.05 I mantles w Formlc acidltechnlcal :45 Hydrogen peroxide; 20 Urea" i- 0.05 Citric acid 0.005

This application is a continuation in part of" my prior copending application, Serial No. 212,301, filed June '7, 1938, for Process of carroting fur and the like and composition therefor.

Various changes in and departures ,from the embodiment of the carroting composition as herein exemplified may be made, all within the scope of the generic invention, it being understood that the matter herein set forth is submitted as illustrative and not in a limiting sense.

I claim:

1. An aqueous carroting solution for treating fur and the like containing as its carroting agent a composition consisting of a volatile hydrolyzing acid selected from the group consisting of nitric, formic and acetic acids, and a volatile oxidizer selected from the group consisting of hydrogen peroxide, organic peroxides and organic .peraci'ds, the hydrolyzing acid having a hydrogen ion concentration equivalent at least to that represented by a concentration of 11-12% by weight of nitric acid of approximately-63% technical, and the solution being substantially free fromnon-volatile carroting agents.

2. An aqueous carroting solution for treating fur and the like containing as its carroting agent a composition consisting of a volatile hydrolyzing acid selected from the group consisting of nitric, formic and acetic acids, and a volatile oxidizer selected from the group consisting of hydrogen peroxide, organic peroxides and organic pera'cids. the hydrolyzing acid having a hydrogen ion concentration equivalent to that represented by a concentration of between 11 and 20% by weight of nitric acid of approximately 63% technical,

and thesolutlon being substantially free from non-volatile carroting agents.

-3. An aqueous carroting solution for treating fur and the like containing as its carroting agent lmately 63%, and also hydrogen peroxide, said solution being substantially free from non-volatile carroting agents.

5. The carroting solution defined in claim 2, in which the hydrolyzing acid consists of acetic acid. f 6. The carroting solution defined in claim 2, in

which the hydrolyzing acid consists of formic acid.

.-7. The process of carroting fur and the like, which comprises treating the fur with an aqueous carroting solution containing as its carroting agent a composition consisting of a volatile hydrolyzing acid selected from the group consisting of nitric, formic and acetic acids, and a volatile oxidizer selected from the group consisting of hydrogen peroxide, organic peroxides and organic 'peracids, the hydrolyzing acid having a hydrogen ion concentration equivalent at least to that represented by a concentration of 11-12% by weight of nitric acid of approximately 63% technical, the solution being substantially free from non-volatile carroting agents, and causing the volatilizatlon of the carroting solution on the fur.

8. The process of carroting fur and the like, which comprises treating the fur with an aqueous carroting solution containing as its carroting agent a composition consisting of a volatile hydrolyzing acid selected from the group consisting 'of nitric, formic and acetic acids, and a volatile oxidizer selected from the group consisting of hy- 5 drogen peroxide, organic peroxides and organic peracids, the hydrolyzing agent having a hydrogen'ion concentration equivalent to that represented by a concentration of between 11 and 20% by weight of nitric acid of approximately 63% concentration of an order represented by approximately 11 to by weight of technical acid of approximately 63%, and also hydrogen peroxide, said solution being substantially free from nonvolatile carroting agents, and causing the volatilization of the carroting solution on the fur.

10. The process of carroting fur and the like, which comprises treating the fur with an aqueous! carroting solution containing as its carroting L agent a composition consisting of nitric acid in a L concentration of an order represented by from 17 to 19% by weight of technical nitric acid of approximately 63%, and also hydrogen peroxide, said solution being substantialy free from non volatile carroting agents, and causing the volatilization of the carroting solution on the fur.

11. The process defined in claim 8, in which the hydrolyzing acid consists of acetic acid.

12. The process defined in claim 8, in which the hydrolyzing acid consists of formic acid.

CONSTANTINE F.FABIAN. M