US2103138A

US2103138A - Process for hardening waterproofing artificial gut produced from animal fibrous material

Info

Publication number: US2103138A
Application number: US105145A
Authority: US
Inventors: Becker Oskar Walter; Weiss Emil
Original assignee: Naturin GmbH and Co
Current assignee: Naturin GmbH and Co
Priority date: 1935-10-15
Filing date: 1936-10-10
Publication date: 1937-12-21
Anticipated expiration: 1954-12-21
Also published as: GB480971A; NL44296C; FR828461A

Description

Patented Dec. 21, 1937 UNITED STATES a p 2,l03,l38

PROCESS FOR HARDENING WATERPROOF- ING ARTIFICIAL GUT PRODUCED FROM ANIMAL FIBROUS MATERIAL Oskar Walter Becker, Heidelberg, and Emil Weiss, Weinheim, Germany, assignors to Naturin G. m. b. H., Weinheim, Germany, a'company of Germany No Drawing. Application October 10, 1936, Se-

eral No. 105,145. In Germany October 15, v

Claims. A (CI. 18-57) the hide may be replaced by heat disintegration or biological loosening or opening up, supplemented by mechanical resolving. The resulting l5 "artificial gut is dried, for example by treatment with hot air, and rendered waterproof in a suitable manner, for example with the aid of distillate of cellulose-containing substances such as wood, or formaldehyde solutions.

When carrying out the aforesaid process the waterproofing of the artificial gut offered considerable diificulties. Hardening with formaldehyde solutions frequently gives rise to insufficientlyresistant sausage cases or skins, which for ex- 'ample do not stand up to the usual boiling test sure of 0.15 atmosphere at 90 C. for minutes).

Moreover in the formalin-hardening process a large portion of the formaldehyde remains adher- 30 ing to the artificial gut, which is subsequently hardened and damaged thereby.

On the other hand the process of waterproofing artificial gut with distillates of cellulose-containing substances, such as wood and the like, yields very non-uniform products. In many cases excessive hardening of the artificial gut, manifested in increased brittleness and friability, takes place. In other cases non-hardened gut is obtained, which is not sufficiently waterproof. In all cases the artificial gut fails to-stand up to the boiling test.

Exhaustive investigations have now shown that the waterproofness or resistance to boiling attained depends substantially on the composition 7 of the hardening liquid. It was found that the hardening properties of the distillates of cellulosecontaining substances are due not only to their content of formaldehyde, but also to their content of other iodine-consuming substances. Whereas the formaldehyde content can be directly determined, the content of other hardening constituents is expressed in terms of the iodine value. The term iodine value is here used in the usual manner to indicate the quantity of iodine expressed in grammes which is consumed.

(capability of resisting an internal excess presby gms. of liquid under the conditions of Romijns iodometric method of determining formaldehyde (Ullmann, Enzyklopadie der techmschen Chemie, 2nd edition, vol. 5, (1928) page 424). The result of the hardening process also depends substantially on the hydrogen ion concentration of the hardening liquid.

According to this invention it has been found that uniform artificial gut, which is neither overnor under-hardened, may be obtained by treating the artificial gut with hardening liquids, preferably distillates of cellulose-containing substances, which have been adjusted to a formaldehyde content of from 0.025 to 0.2%, preferably 0.1 to 0.15%, an iodine value of from 3.5 to 8.5, preferably 5.9, and a pH value of from 2.5 to 3.0.

According to this invention it was further found that certain compensations may be eifectedin the Thus,

composition of the cellulose derivatives. too. low iodine values of the distillates may be compensated by increasing the formaldehyde content. H

The iodine-consuming substances in the wood distillates employed with the exceptionof formaldehyde can only be determined with difficulty.

They may, however, be replaced by compounds known per se which occur in distillates of cellulosic substances, such as coniferyl alcohol, eugenol, acetaldehyde, pyrocat-echol, pyrogallol, quinone and others. However these substances also are only sufficiently active if they are employed in quite definite combination with formaldehyde and formic acid or acetic acid and with quite definite pH values so as to produce mixtures which fulfil the hereinbefore indicated directions with regard to formaldehyde content, iodine value and pH value.

The process of this invention is with advantage carried into effect by first drying the artificial gut discharging from the annular nozzle. This may be effected by conveying the gut in the form of a continuous band through drying channels in which it is subjected to the action of hot air.

Preferably air is blown from the nozzle head into the interior of the tube being formed and the artificial gut dried in this inflated condition. The hardening is likewise with advantage effected whilst the endless tube is in this inflated condition.

For the production of the hardening liquid cellulose-containing substances, particularly wood and waste products of wood, for example sawdust, are subjected to distillation. The crude distillate obtained, which is in general more highly oxidized than the distillate obtained in the carbonization of wood, contains up to 0.5% of formaldehyde and has an iodine value of about 42.5. The crude distillate after a distillation is if necessary adjusted by the addition of water to a formaldehyde content. of, for example, 0.12%, whereby the iodine value is also decreased. If the iodine value of the diluted distillate amounts to less than 3.5, crude distillate is added thereto until the iodine value exceeds 3.5. In this case the formaldehyde content may be allowed to exceed the value indicated above. Alternatively a wood distillate may be added, the iodine value of which is very high in proportion to the formaldehyde content, for example 1. The distillate is thereafter adjusted to pH values of between 2.5 and 3.0 by the addition of formic acid or acetic acid, if it is too alkaline and by the addition of ammonia if it is too acid.

The continuous artificial gut is painted-over or the distillate with regard to iodine value and formaldehyde content and amounts to from 2 to 30 days. After this period of action the gut is washed or rinsed with water having a pH value of 8, whereby it first becomes cloudy and then glassy. The excess portion of the hardening substances is washed away thereby. The gut is then again dried.

When employing distillates as aforesaid uniform products are obtained, which, with regard to strength and waterproofness, fulfil all re-. quirements demanded of artificial gut. Artificial gut as aforesaid could be subjected for half an hour and longer at an internal excess pressure of up to 0.2 atmosphere to temperatures of about C. without bursting.

Examples 1. Artificial gut produced from animal fibrous material, for example in accordance with French patent specification No. 723,066,.is treated by repeated spraying with a distillate prepared as follows:

By distilling moist saw dust, a distillate is obtained, litres of which contain 0.5% of formaldehyde and which has an iodine value of 26.5. To these 100 litres there are added 317 litres of water. .The iodine value now amounts to 6.4 and the formaldehyde content to 0.12%. This diluted solution amounting to 417 litres has a pH value of 3.1 and is adjusted by the addition of 282 gms. of formic acid to a pH value of 2.68.

The gut after treatment with the distillate is dried and kept for three days at 25 C. The gut is then washed for about 3 hours with'water having a pH value of 8 and is then again dried.

2. Artificial gut produced in accordance with French patent specification No. 766,016 is treated with a hardening liquid prepared as follows:

200 gms. offormic acid-(50%), 83.5-gms. of formaldehyde (30% by weight) and 1015 gms. of pyrocatechol are dissolved in 100 litres of water. The iodine value amounts to 8.5, the formaldehyde content to 0.025% and the pH value to 2.7.

After five-times spraying with this hardening liquid andsubsequent drying, the gut is stored for 14 days at 25 C. and 70% relative air moisture and is thereafter freed from the excess of the V artificial gut with hardening liquids containing from .025 to 2% of formaldehyde, and iodine consuming substances occurring in the distillates of cellulose containing substances, said hardening liquids having an iodine value of from 3.5 to 8.5

and arm value of from 2.5 to 3.0.

2. A process according to claim 1, wherein distillates of cellulose-containingsubstances are employed as hardening liquids.

3. A process according to claim 1, wherein distillates of wood are employed as hardening liquids.

4. A process according to claim 1, wherein mixtures of iodine-consuming substances occuring in the distillates of cellulose containing substances, formaldehyde and formic acid are employed as hardening liquids.

5. A process according to claim 1 wherein mix tures of iodine-consuming substances occuring in the distillates of cellulose containing substances, formaldehyde and acetic acid are employed as hardening liquids.

6. A process according to claim 1, wherein dried artificial gut is hardened.

7. A process according to claim 1, wherein the artificial gut is hardened in the form of a continuous band.

8. A process according to claim 1, wherein the artificial gut is hardened in an air-inflated condition.

9.; A process according to. claim 1, wherein the artificial gut is repeatedly treated with the hardening liquid and dried between each hardening treatment.

10. A process according to claim 1, wherein the artificial gut is repeatedly treated with the hardening liquid and dried between each hardening treatment andafter the last hardening treatment.

OSKAR WALTER BECKER. EMIL WEISS.