US2353947A - Process for the treatment of ramie and allied fibers - Google Patents

Description

Patented July 18, 1944 PROCESS FOR THE TREATMENT OF RAMIE AND ALLIED FIBERS Frank A. Svoboda, Cicero, and Allen Skolnik,

Chicago, Ill.

No Drawing Application April 17, 1941,

Serial No. 388,986

1 Claim.

- This invention relates-to the treatment of vegetable fibers suchas ramie and allied fibers, to prepare the same for use in the manufacture of textiles and the like.

As is well known, ramie has long been considered as a potential source of textile fiber due to the fact that its fiber is particularly suited for textile purposes and also because it can be raised easily in areas which presently lie waste because of their unsuitability for the cultivation of other products. Additionally, ramie propagates readily and under suitable condition yields as many as four crops in one year.

However, because of the peculiar structure of the ramie plant in which each fiber is sheathed in anenvelope of normally insoluble gums which along with other objectionable constituents must be removed in order to render the fiber susceptible to the usual textile process of combing and spinning, and because of the difficulty in do-= ing the same, ramie has been unimportant commercially as a source of textile fiber.

In the past; various attempts have been made to provide commercially acceptable processes for isolating the pure fiber in a condition such that it may be used advantageously in combination with other textile fibers in the textile art. These processes have not been entirely satisfactory because in the removal of the residual bark and in the degumming operation, the cellulose structure of the fiber is weakened or otherwise injured, thus rendering it unfit for commercial use.

Accordingly, it is an object of this invention to provide a process of treating ramie so as to isolate and recover strong soft fibers particularly suitable for use in the manufacture of textiles and the like.

A further object of this invention is the proage stacks are subjected to a preliminary dewooding or debarking operation such as may be effected in any well known decorticating machine. The resultant material is in the form of crude fiber having bark adhering to the fiber 'and undesirable gums binding the fiber. For the purpose of removing the undesirable barkv and gums'we then introduce the crude fiber in a copper or glazed vessel and then add a treating agent in sufficient quantity to completely immerse the fiber. The treating agent is preferably an aqueous solution of caustic soda, ammonium carbonate and ammonium chloride containing a wetting agent such as soap, saponifiable oils or the like. We make use of glazed or copper vessels because we have found that in most instances the prior art processes have been unsuccessful due to the reaction of the treatin agents with the vessels in which they are contained. In the use of the above described vessels no chemical reaction occurs with the treating agent contained therein.

The treating agent for each 100 pounds of fiber under treatment may consist of 20-30 pounds of caustic soda, of a pound of ammonium chloride, of a pound of ammonium chloride and 2 pounds of soap chips. The

' stock is then maintained at a boiling temperature for a period of from 45 to 60 minutes, de-

pending upon the quality and condition of the material being treated... This treatment renders the gums soluble and completes the dewooding ing rollers and is centrifuged to remove excess water and is then subjected to a further stage of purification, In this stage, the fiber is introduced in a glass or glazedvessel containing a solution of caustic soda having a concentration between 20% and 25%. After treatment for a period from 2 to 10 hours, depending upon the nature and condition of the material treated the fiber will be completely freed of gum and bark.

The fiber is again washed and dried, either by squeezing or centrifuging.

The fiber at this stage ,of the process will be found to be substantially white. Where the fiber is to be dyed no further bleach is required, the

fiber being in suitable condition for dyeing. If,

' however, further bleaching is found desirable, the

fiber may. be immersed in a chlorine solution or may be subjected to any desirable bleaching treatment. After bleaching the fiber is washed and dried.

The fiber resulting from the above process is soft, and as strong as the original fibers prior to chemical treatment and is particularly suitable for use in textile processes.

While we have described in detail the preferred 55 practice of our invention, it is to be understood fibrous material 20-30 pounds of caustic soda, pounds or ammonium chloride, pound ammonium carbonate and 2 pounds of soap,

washing said fiber and treating same in a bath of caustic soda having a concentration of from 20-25% for a period of time between 2 to 10 hours, and thereafter washing and drying said fiber.

FRANK A. SVOBODA. ALLEN SKOLNIK.