US1990449A - Process of weighting fibers and the product thereof - Google Patents

Description

Patented Feb. 5, 1935 PROCESS OF WEEGHTING FIBERS AND PRODUCT THEREOF THE Olav Berg, Paterson, Max Imhoff, Clifton, and Oernulf E. Heiberg, Hawthorne, N. 3.; said Heiberg assignor to said Berg and Irnhoif; Albert Catalane and William W. Evans executors of said Olav Berg, deceased No Drawing. Application August 24, 1926,

Serial No. 131,310

16 Claims.

This invention relates to the chemical treatment of fibers, especially those of silk, for the purpose of increasing their size and weight, and to the product of such treatment. Our process relates more particularly to the treatment of tin weighted silk and its object is to provide new and useful steps to be taken after a preliminary tin weighting treatment, which have many advantages both as to the method employed and as to the resultant article, over such as have been known heretofore.

It is customary in the art to treat silk fibers with a solution of tin tetrachloride and to follow this treatment with one in sodium phosphate. These treatments are usually repeated until the desired weight is obtained. But these treatments are expensive and no great amount of such loading is possible without injuring the elasticity and strength of the fibers, making them tender and brittle and subject to deterioration with age.

The important feature of our invention is that after the silk is given a preliminary treatment with some other weight giving compounds, we apply a treatment with zinc or cadmium compounds,or both zinc and cadmium compounds. The preliminary treatment may be any one of the known methods of tin weighting. We have found that practically any soluble zinc or cadmium compound can be used, but not all with the same advantage. The result is greatly dependent upon the nature of the solution.

If silk fiber has been preliminarily treated with tin tetrachloride and sodium phosphate, a treatment in zinc or cadmium sulphate or nitrate 0 will not add materially to the weight and volume of the fiber. This is probably due to the fact that when a small amount of zinc oxide or cadmium oxide has been taken up by the fiber, sulphuric or nitrate acid will have been liberated and will prevent any more oxide from being taken up. We therefore prefer to use a zinc or cadmium salt of a weak acid, for instance, zinc or cadmium, acetate or formate.

A zinc or cadmium salt of a strong acid, for instance, zinc sulphate, can be used with the same advantage as a zinc or cadmium salt of a weak acid, for instance, zinc acetate, if it is used in a buffer solution, that is, in a solution of such a nature that a small addition of acid or alkali will only make a small relative change in the hydrogen-ion concentration. A solution of sodiurn acetate is suitable for this purpose.

For certain purposes it is of great advantage to use the zinc or cadmium in an alkaline solution. Such a solution can be prepared by dissolving zinc or cadmium oxide in a solution of caustic alkali. It may also be prepared by mixing a solution of a zinc or cadmium salt with ammonia, ammonia being used in sufiicient excess to produce a clear solution. Sometimes we prefer to use the zinc or cadmium salts in an alkaline solution which contains salts of other metals" or positive groups. We sometimes use ammonium salts for this purpose.

The process may terminate after the treatment in the solution of the zinc or cadmium compound, but usually we prefer to follow that step with a treatment in a fixing bath. For this purpose we can use a large variety of different chemicals, for instance, soluble phosphates, soluble silicates, or soluble ferrocyanides. We can also use a number of combinations of these and other substances. For instance, as a fixing treatment we can use a bath of sodium phosphate, follow that with a bath of sodium silicate and finally give a treatment in a fatty soap.

The application of a fixing bath has the advantage of increasing the Weight and volume of the fiber, and to make the zinc or cadmium or zinc and cadmium compounds present on the fiber, more insoluble. In some cases it also improves the lustre and scroop of the fiber. The'fixing bath usually imparts to the fiber the property of taking up more zinc oxide or cadmium oxide if it is again submerged in a solution of a zinc compound or a cadmium compound. By thus-alternately applying to the fiber a zinc or cadmium compound and a fixing bath, any desired increase in weight can be obtained.

If '75 pounds of boiled oil or degummed silk is treated in a bath of tin tetrachloride of a Baum strength of 20 at a temperature of Fahrenheit for one hour, washed and treated in a slightly alkaline 5 Baum solution of sodium phosphate at 170 Fahrenheit for one hour and then washed, its weight will be increased to 86 pounds. Repeating these steps will increase its weight to 102 pounds. These steps are old and well known. We now put the treated goods into a 3 Baum bath of zinc acetate at 140 Fahrenheit for one hour and then wash. After this the weight of the goods is 108 pounds. A sodium phosphate treatment of 6 Baum strength and 140,Fahrenheit for one hour will increase the weight to pounds. A repetition of the zinc acetate and sodium phosphate baths increases the weight to 139 pounds. Another repetition of the zinc acetate and sodium phosphate baths increases the weight to 169 pounds. These zinc acetate and sodium phosphate treatments may be repeated again and again with further additions of volume and weight.

Thus the desired increase may be obtained without the undesirable use of an excess of tin compounds. By this process the size of the fiber will greatly increase, which is the principal object of any weighting process. The goods are soft and fiufiy and their appearance greatly improved. Furthermore, this treatment is less expensive than the former method of repeating tin weighting treatments to obtain similar weights.

We find it desirable to use one or more intercalated treatments with a soluble lead salt, such as lead acetate as described in Patent No. 1,579,- 628, issued April 6, 1926, as this has the effect of improving the fiber in many ways. It not only increases the weight but improves the tone of the fiber, increases its elasticity, improves its dyeing properties and has a preservative effect. This lead treatment may be applied at any stage after the tin treatment has been applied. We now prefer to follow the lead treatment with a bath of sodium phosphate. 3

In the aforesaid Patent No. 1,579,628, the ways of using lead acetate have been described in detail, and the same ways of treating fibers can be followed by substituting zinc acetate, with many of: the same advantages, especially if some soluble lead compound is used in addition to the zinc treatment.

By the methods now in vogue and employed in the past for the weighting of silk, sodium silicate or other soluble silicates are frequently, applied in connection with tin compounds. Silk fibers can be weighted by alternately treatingthe fiber in a solution of tin tetrachloride and a solution of sodium silicate, but it is more customary first to subject the fiber to the alternate action of baths of tin tetrachloride and of sodium phosphate and thereafter to treat it in a solution of sodium silicate. Such application of sodium silicate will greatly increase the size of the fiber. But silk weighted by tin compounds in connection with sodium silicate is very often tender and brittle and will deteriorate in a comparatively 'short time. After silk, for example, has been weighted by alternate treatments in tin tetrachloride and sodium phosphate, it will take up a certain amount of silicate when immersed in a solution of sodium silicate, but after one silicate treatment it has practically no ability to take up more.

' It is'known also that if the fibers after the silicate treatment are subjected to a bath of practically any metallic salt, they will take up about as much silicate as they did the first time, if they are again subjected to the action of a solution of a silicate. So it is possible to increase the weight and volume of fibers which have been treated as hereinbefore described by subjecting them to a bath of sodium silicate.

In thiscase asbefore, one or more intercalated treatments with a soluble lead compound will improve the character of the fibers. And as before the process maybe ended with a silicate treatment. The process may be stopped after any p- The goods so treated aresoft and fluffy. Goods containing a considerable amount of tin weighting with silicate applied by former methods are subject to shrinkage which undesirable characteristic is greatly reduced by this new method. This method is much cheaper than the ordinary tin weighting and the appearance of the goods is better.

We have found that the goods may be given a still greater volume with few treatments, if the zinc or cadmium compound used be in the form of an alkaline solution. For example: by two treatments in tin tetrachloride and two treatments in sodiiun phosphate as previously described, the weight of 75 pounds degummed silk will be increased to 102 pounds. A treatment in sodium silicate 3 Baum, F. for one half hour will bring the weight up to 116 pounds. These steps are old.

We now put the silk in an alkaline bath of a zinc salt, prepared as follows: ammonia is added to a bath of zinc acetate thereby forming a precipitate, but the addition of ammonia is continued until the precipitate is dissolved. This alkaline bath of zinc salt is used at 3 Baum and 140 F. for one hour, after which the goods are washed- This adds somewhat to the weight. When the silicate treatment before described follows, the weight will increase to pounds. Another treatment in the alkaline bath of zinc brings the weight up to pounds. Another bath of sodium silicate gives further increase of weight and volume.

Thus the desired weight and volume can be obtained with fewer steps than if zinc or cadmium had been used in a neutral solution. As

before it is sometimes desirable to add a lead compound to the goods and this may be done as already pointed out.

Again the process may be ended after an the fixing baths described.

The order and number of steps taken may be varied after the tin treatment has first been applied. The process may be applied to fibers in the skein or to textiles and they may be brought to any desired weight or volume. The treated fibers forma new and useful material.

This description is for illustrative purposes only, as we know that the strengths, temperatures, acidities and times mentioned, as well as the order and number of steps, and even the chemicals specified, may be varied without departing from the scope of the invention, and we intend no limitaitons other than those imposed by the appended claims.

It is understood from this disclosure that the water washing steps, or cleaning with weak acid or alkaline solutions, which are not included in the claims, may be used after each bath specified.

It is our belief that cadmium is, in a patentable sense, the full equivalent of zinc, and that the use of cadmium or of cadmium compounds instead of zinc or zinc compounds as specified in the claims, would come within the scope of the claims.

What We claim is:

1. A process of treating tin weighted fibers which comprises treating such fibers in a solution of an organic zinc salt.

2. A process of treating tin weighted fibers which comprises treating such fibers with a zinc salt in a solution of low acidity which is maintained at a substantially constant pH value.

3. A process of treating tin weighted fibers which comprises treating such fibers in a solution of zinc acetate.

4. A process of treating tin weighted fibers salt in a solution of low acidity which is maintained at a substantially constant pH value and then in a bath of sodium phosphate.

6. A process of treating tin weighted fibers which comprises treating such fibers successively in baths of a zinc salt in a solution of low acidity which is maintained at a. substantially constant pH value and in a solution of sodium phosphate.

7. A process of treating tin weighted fibers which comprises treating such fibers in successive solutions of zinc acetate and of sodium phosphate.

8. A process of treating tin weighted fibers which comprises treating such fibers successively in baths of a zinc salt in a bufier solution and in a solution of sodium phosphate.

9. A process of treating tin weighted fibers which comprises treating such fibers in a solution of zinc acetate and in a bath of lead acetate.

10. A process of treating tin weighted fibers which comprises treating such fibers in solutions of zinc acetate, of lead acetate and of sodium phosphate.

11. A process of treating tin weighted fibers which comprises treating such fibers in successive solutions of zinc acetate and. of sodium phosphate with an intercalated treatment with a soluble lead compound.

12. The process of treating silk by subjecting it to a bath containing tin, washing the silk, subjecting it to a bath containing sodium phosphate, Washing the silk and thereafter subjecting it to a bath containing zinc acetate, washing the silk and subjecting it to a bathv containing sodium phosphate.

13. The process of treating silk by subjecting it to a bath containing stannic chloride and thereafter subjecting it to a bath containing zinc acetate.

14. A fabric weighted by the addition of stannic chloride and zinc acetate.

15. A process of treating tin weighted fibers which comprises treating such fibers with a zinc salt in a solution of low acidity which is maintained at a substantially constant pH value, with an intercalated treatment with a soluble lead compound.

16. A process of treating tin weighted fibers which comprises treating such fibers with a zinc salt in a solution of low acidity which is maintained at a substantially constant pH value, and then in a bath of sodium phosphate and in a bath of a soluble lead compound.

OLAV BERG. MAX IMHOFF. OERNULF E. HEIBERG.