US1767663A - Process of treating fabric - Google Patents

Description

Patented June 24, 193O p UNITED. STATES PATENT OFFICE ROBERT E. FULTON, F PITTSBURGH, PENNSYLVANIA, ASSIGNOIR. TO THE KOPPERS COMPANY, A CORPORATION OF DELAWARE PROCESS OF TREATING FABRIC No Drawing. Application filed June 7, 1927. Serial No. 197,236.

This invention relates to the treatment of partial solution ,or gelatinization occurs, refabric and more particularly to a process of moving any excess of'gelatinizing liquid and coating or filling woven fabric with cellupressing and finishing the material in the losic material. I usual manner.

An object of my invention is to provide a In order that my invention may be clearly coated or filled fabric of improved surface set forth and understood, I'now describe, but quality and strength. without limiting my invention to such spe- -A further object of my invention is to cific illustrative example, the preferred provide a process of coating or filling fabric manner in which it is accomplished and with cellulosic material that is free from performed.

certain difficulties and disadvantages of the A fabric base, which may consist of looseprior art. ly woven cloth, is covered with a layerof My invention has for further objects such pulp, such as sulphite pulp or cotton rag other operative advantages and results as pulp, or other cellulosic material in finely may hereinafter be found to obtain. divided state. The layer of cellulosic mate- The manufacture of coated and filled fabrial may be of an. desired thickness and ric is well known. The processes of the may be applied to 0th sides, of the fabric prior art have, in general, attempted to probase or to only one side thereof, as desired. duce such material by spreading a solution Spreading the cellulosic material uponthe m of cellulosic material, such as viscose, upon fabric base is easily accomplished in a man- 70 the fabric. The difiiculties met with in these ner Well known to those familiar with the processes are not easily overcome. Viscose art. and other cellulosic solutions, such as a solu- The fabric and the Superimposed cellution of cellulose in calcium thiocyanate solulosic pulp are more or less completely dried tion, are viscous and the viscosity of such by passing them between hot squeezing rolls solutions issubject to variation upon exposwhereby heat and pressure is applied ure to the atmosphere, temperature fluctua thereto. 1 tions, handling and the like. Consequently, After leavlng the rolls, the coated fabric it is very diflicult to obtain layers of celluis passed through a solution capable of :1) losic material of uniform thickness. Coneffecting partial solution or gelatinization of 0 stant care is required in s reading the celluthe pulp. I prefer to use a solution of callosic solution upon the fabric, and adjustclum thiocyanate having aboiling point ofments of feeding devices must be made very from about 134 to 140 C. and containing frequently. from 20% to% of formaldehyde, ,but-

as The high viscosity of solutions of celluother calcium thiocyanate solutions andstill s5 lose in calcium thiocyanate solutions makes other gelatinizing solutions, or solvents, it difficult to obtain thin layers therefrom. known to the art may be employed. With Thick layers are prone to crack and peel respect to the preferred solutions, I have from the fabric base. found that beneficial. results may be ob- 40 I overcome the difliculties and disadvantained by maintaining a temperature of tages of the prior art by spreading cfellulosic from 20 to 4:0 C. therein, but other tempulp upon a fabric base and subsequently peratures may be employed, especially when Q accomplishing the partial solution or gelasolutions of different strengths or kinds are tinization of the pulp without, however, employed. 4% materially affecting the fabric base. I ac- The fabric is preferably not permitted to 9.3 complish this object by coating the fabric remain in the gelatinizing bath for an eirbase with cellulosic pulp, immersing the tended period but is removed and squeezed Whole in a gelatinizing bath, such as a soluby being passed through rolls or otherwise tion of calcium thiocyanate 'of regulated treated to remove an excess liquid which strength, allowing the material to stand until may have adhered t ereto. The material which now retains a suflicient amount of gelatinizing liquid to accomplish the desired result is allowed to stand for a predetermined period to permit gelatinization of the pulp fibers. It may be wound upon a reel or folded or handled in any other convenient manner during this gelatinization period.

When the desired degree ,of gelatinization is attained, the material is sprayed with water or subjected to the action of steam or otherwise treated to remove or dilute the gelatinizing agent and thereby coagulate the gelatinized material and the cloth is then passed through warm squeezing rolls orother suitable; apparatus whereby the gelatinized pulp is pressed into, and incorporated with, the fabric base. and dried in the usual manner.

According to the results desired, the raw materials of my process and the procedure thereof may. be varied over a wide range, as will be apparent to those skilled in the art. For example, fabric bases woven from flax, hemp, jute, or other fiber may be treated and the cellulosic pulp employed 'as fill-- ing or coating agent may be obtained from many sources.

Moreover, the sequence of steps may be varied in carrying out the process of my invention. For example, under certain circumstances, it may be advisable to squeeze or press the coated fabric before spraying or steaming it to dilute the gelatinizing agent.

The natur'e of the product obtained in the process of my invention will var :ac-

, cording to the materials employed an also according to various other factors, such as the duration of the period of gelatinization. Ordinarily, however, I prefer to allow gelatinization of the pulp to proceed to the greatest practicable extent without, however, materially affecting the fabric base. Partial gelatinization of the fabric base, however, is not necessarily a disadvantage as it may assist in forming a bond between the base and the coating material.

The advantages of my process are at once apparent to those skilled in the art. The

difliculties of handling extremely-viscous cellulosic materials that may be subject to fluctuations in viscosity are entirely obviated. The coating or filling which results The cloth is then washed fabric and subjecting the fabric and pulp to a liquid effective to gelatinize the pulp.-

3, The process of treating fabric which comprises spreading cellulosic pulp over the fabric, subjecting the fabric and pulp to the action of a cellulose solvent, allowing gelatinization of the pulp to take place and removing excess solvent.

4. The process of treating fabric which comprises spreading cellulosic pulp over the fabric, immersing the fabric and pulp in a solution of -calcium thiocyanate, removing the fabric and pulp and allowing them to stand until the pulp is at least partially gelatinized but without materially affecting the fabric and pressing the gelatinized pulp into the fabric.

5. The process of treating fabric which comprises spreading cellulosic pulp over the fabric, pressing and drying the fabric and pulp, immersing the dry material in a solution of calcium thiocyanate' and formaldehyde, removing the treated fabric and pressing it to remove excess solution, allowing it to' stand until gelatinization of the pulp occurs, removing the remaining solution and washing and drying the coated fabric.

.6. The process of treating fabric which comprises spreading finely divided cellulose over the fabric, subjecting the whole to the action of a cellulose solvent until gelatinization of the applied cellulose is effected and subscribed-my name this 2nd day of J une,

ROBERT R. FULTON.

is much more uniform and adherent and will not crack or peel. Moreover, a considerable saving 1n chemlcals is-effected.

My rocess is not limited to the specific I examp es given hereinabove by way of i us- I claim-as my invention: Y 1. The process of'treating fabric which comprises spreadingcellulosic pulp over the tration' but ma variously be embodied within the scope o the claims hereinafter made.

fabric and then effecting a gelatinization of i the pulp.