US2290081A - Art of producing gelatin and glue - Google Patents

Description

Patented July 14, 1942 UNETED STT 2,290,081 ART OF PRODUCING GELATIN AND GLUE Leo Wallerstein,

New York, N. Y., and Julius Pfannmullcr, North Plainfield, N. J., assignors to Wallerstein Company, Inc.,

New York, N. Y.,

a corporation of New York No Drawing. Application July 2'7, 1938, Serial No. 221,642

6 Claims. (Cl. 260-118) This invention relates to the art of producing gelatin and glue.

In producing gelatin and glue from raw material of animal origin, such as bones, skins, cartilage and the like, it is the usual procedure, after removal of inorganic substances, such as tricalcium phosphate, etc., to steep the raw material, which contains collagen, in milk of lime. Ordinarily, these lime liquors are changed or renewed from time to time and the treatment is continued for a considerable length of time.

In the case of so-called dried buffalo pieces, for instance, the raw material is steeped in lime liquors until the material is sufiiciently swollen and bleached and is no longer firm, but soft. This ordinarily requires from at least four weeks to several months.

After the lime liquor treatment, the raw material is washed and de-limed or neutralized with suitable acids. It is then subjected to a so-called cooking process by which a solution of gelatin is obtained. This solution is subjected to various filtering and cleaning operations and then evaporated and dried to obtain the finished product, gelatin or glue.

The liming or pre-cooking treating is of great importance because the collagen and other tissues must be ripened or chemically digested to such a form that, in the subsequent cooking operation, such tissues easily go into solution without leaving too much residue and Without necessitating excessive cooking temperatures.

It is an object of the present invention to provide a process of treating raw materials of animal origin for the production of gelatin or glue such that the time required for the requisite ripening or chemical digestion is materially reduced.

It is a further object of the invention to provide such a process that not only attains the end just referred to but also makes possible a higher yield and a better product.

In carrying out the present invention we add to the usual lime liquor a relatively small amount of a reducing sulphur-oxygen compound. Compounds suitable for carrying out the process of the invention are characterized by being stable in dry condition and having a substantially greater reducing power in solution than that of the sulphates, sulphites, sulphides or thio-sulphates. While various such compounds may be used, the invention is carried out to what is now considered the best advantage by the use of compounds of the class of hydrosulphites and sulphoxylates and corresponding organic compounds of sulphur and oxygen. We have found, for example, that sodium hydrosulphite, sodium sulphoxylate, sodium formaldehyde sulphoxylate or zinc calcium hydrosulphite are suitable and satisfactory.

In this connection, we are aware that there is some existing confusion in text books and chemical dictionaries with respect to the terms hydrosulphite and hyposulphite. However, in the present application sodium hydrosulphite means the compound Na2S2O4 and in referring to hydrosulphites in general we refer to salts of hydrosulphurous acid (H2S2O4) If, in the pre-cooking treatment, only one lime liquor is utilized, the sodium hydrosulphite or other compound is, of course, added to that liquor. If the lime liquor is changed during the digestion or pre-cooking period, the sodium hydrosulphite or other compound may be added to one, some or all of the lime baths, depending on the raw materials used and the desired time interval for obtaining proper digestion. If several renewals of lime liquor are put into effect, addition of the sodium hydrosulphite or other compound to one bath will materially reduce the period necessary for obtaining proper digestion. Addition to more than one lime liquor further shortens the digestion period, for a given raw material.

While the amount of sodium hydrosulphite or other compound added may vary within a considerable range, about one half of one per cent (0.5%) based on the dry weight of hides treated has been found suitable and satisfactory.

If sodium hydrosulphite is used, it may be added in ordinary commercial form or its presence may be obtained by adding a mixture of materials including sodium hydrosulphite. An example of such a mixture is disclosed and claimed in an application filed by us of even date herewith (Ser. No. 221,643), said mixture including sodium hydrosulphite and one or more agents which tend to stabilize the hydrosulphite against the deteriorating effects of moist and damp air. If a mixture is used, enough of the mixture should be added to give substantially the same amount of sodium hydrosulphite as would be obtained if the latter were added in commercial form.

The hide-water ratio and the amount of lime used may conveniently be in accordance with usual practice. For example, a hide-water ratio of 1:4 (by weight) and about 10% lime, based on skin dry weight, have been found suitable and satisfactory.

After the raw material has been properly ripened or digested it is washed, neutralized and cooked and the resulting gelatin solution is filtered, cleaned, evaporated and dried in the usual manner to produce gelatin or glue.

Whether the hydrosulphite or other compound attacks the collagenous tissues and, if so, what the mechanism of the attack may be, has not been fully determined. The fact remains that when a compound of the class referred to is added to one or more of the lime liquors, the pre-cooking or digesting treatment is materially accelerated as to the requisite time involved; the ultimate yield is higher; and the gelatin or glue has a lighter and more desirable color, as compared to results obtained when no such compound is added.

The following procedures example:

are given by way of Example I Soak 100 pounds dried hides, i. e., so-called bufialo pieces, in water at 60-70 F. for one day.

Transfer the hides to a bath consisting of 400 pounds (48 gallons) of water containing pounds of lime. Add one half pound sodium hydrosulphite. Leave the skins in this liquor at room temperature (6070 F.) for one week.

Transfer to a new lime liquor consisting of 400 pounds water and 10 pounds lime and leave for one week. Transfer to a new and similar lime liquor and leave for 6 weeks.

At the end of this period the raw material is ready for cooking and subsequent operations.

Example II Soak 283 pounds of bufialo pieces in Water at 60-70 F. for one day.

Transfer the hides to a bath consisting of 1130 pounds water (136 gallons) containing 28 pounds lime. Leave for 3 days.

Transfer the hides to a new liquor containing 1130 pounds water, 28 pounds lime and 1.4 pounds sodium hydrosulphite. Leave for 16 days.

Transfer the hides to a fresh liquor identical in composition with the previous one and leave for 3 weeks.

At the end of this period the raw material is ready for the cooking and subsequent operations.

Example III Soak 100 pounds buifalo pieces in water at 60-'70 F. for one day.

Put soaked pieces in a liquor consisting of 400 pounds water and 10 pounds lime. Leave for 2 days.

Transfer to a new lime liquor of same composition and add one half pound sodium hydrosulphite. Leave for about one week.

Transfer to a new lime liquor of the same composition as the first. Stir occasionally.

After a few weeks the raw material is ready for cooking.

Example I V Follow the procedure of Example III except that the sodium hydrosulphite is added to the third bath instead of the second.

What is claimed is:

l. A process of accelerating the ripening and digesting of collagen-containing raw material of animal origin in lime liquor, for the preparation of gelatin or glue, which comprises adding a hydrosulphite to the lime liquor.

2. A process of accelerating the ripening and digesting of collagen-containing raw materal of animal origin in lime liquor, for the preparation of gelatin or glue, which comprises adding sodium hydrosulphite to the lime liquor.

3. In the process of accelerating the ripening and digesting collagen-containing raw material of animal origin in a plurality of lime baths, for the preparation of gelatin or glue, the improvement which comprises adding a hydrosulphite to at least one of the lime baths.

4. In the process of accelerating the ripening and digesting collagen-containing raw material of animal origin in a plurality of lime baths, for the preparation of gelatin or glue, the improve ment which comprises adding sodium hydrosulphite to at least one of the lime baths.

5. A process of accelerating the ripening and digesting of collagen-containing raw material of animal origin in lime liquor, for the preparation of gelatin or glue, which comprises adding sodium hydrosulphite in an amount approximating one-half of one per cent based on the dry weight of said raw material.

6. A process of accelerating the ripening and digesting of collagen-containing raw materials of animal origin in lime liquor, in the preparaing to the lime liquor a compound selected from the class consisting of hydrosulphites and sulphoxylates.

LEO WALLERSTEIN. JULIUS PFANNMULLER.