US1839168A - Fabric for gas protection masks or the like and method for producing same - Google Patents

Description

Patented Dec. 29, 193i umrsio sraras PATENT orric GERHLARD KARL EMIL HEINRICH STAMPE, F LUEIBEOK, GERMANY, ASSIGNOR 'I'O CTTO HEINRICH DRAGER, OF LUEBECK, GERMANY FABRIC FOR GAS PROTECTION MASKS OR THE LIKE AN D METHOD FOR PRODUCING SAME No Drawing. Application filed March 26, 1929, Serial No. 350,136, and in Germany December 20,

It has frequently been tried to waterproof or impregnate fabric in such manner, that the pieces of clothing or garments, and so on, which are manufactured therefrom, have the additional advantage of giving protection against penetration of poisonous gases to the skin of the wearer. For instance, fabrics have been saturated with alkaline substances successfully, so as to secure protection against gases having a specific acid character, such as chlorine or phosgene.

Gases having no special chemically reactive qualities can be neutralised or made harmless by absorption. Now it is true that every fabric, owing to its generally colloidal nature, absorbs gas to a slight extent. However, t his quality cannot be made use of for removing larger amounts of gas that may contact with the fabric. According to the present invention, the natural absorptive power of the fibres of the fabric is manifoldly increased by coating the fibres with active inorganic gels. If this is done in such manner that the single fibres are not cemented to a coherent surface in the course of operation, the fabric will retain its full permeability to air. This is of importance particularly where garments are concerned which cover a large portion of the surface of the human body. If such garments were made of a fabric which is not permeable to air, they would very soon become unbearable to the wearer because they would prevent the normal breathing of the skin. The absorbing fabrics made according to this invention remove merely from the air, which are capable of being absorbed, without hindering the circulation of the latter.

The impregnation of the fabric may be secured by applying the ready-made gel to the fabric either in a plastic state or in the state of the corresponding sol whereby the gel forming material may be evenly distributed over the fabric. It may be of advantage to apply this material pressing or rolling it on. The fabric so coated is then dried and the gel applied to the fibres is activated in a known manner by heating to a higher temperature.

such ingredients (poisonous).

on both sides by Another possibilit of a l in the el on to the fibres resides in al f w ing the gel to originate on the fibres themselves. Gels are frequently produced directly from a solution. Also, they are produced by colloidal precipitation from a solution with the aid of a second solution. For this reason the fabric may be saturated to its full extent by dipping it at first into one of the solutions and allowing it to remain therein for a while, then taking it out, allowing the excess solution to drop off, and then bringing it into the solution of precipitation. This solution then precipitates the gel upon the fibres themselves. If the fabric is then sufficiently washed, dried, and activated in known manner, there is the advantage of an extraordinarily firm connection of the gel impregnation with the individual fibres of the fabric.

One of the gels dled is the silica-gel. This also is particularly well adapted for carrying out the described method. The fabric, for instance a jute fabric having wide meshes and thick threads (the material of the ordinary sacks) is at first subjected to the action of a sodium water glass solution, (for instance-of a density of 1,2) for a long time. Then thewater glass solution is allowed to run off from the fabric, which is quickly introduced into a solution of ferric chloride of the same strength or density. Instead of this solution, a concentrated hydrochloric acid or other suitable means for precipitating silicic acid may be used. Hot solutions are specially suitable. In treating with these solutions, the silicic acid is precipitated upon and into the fibres colloidally. The surplus of the means of precipitation is now removed by thoroughly washing it out, finally with hot water, and the impregnated fabric is then dried and activated in a manner well known in producing silica gel.

en impregnating with some kinds of gels, the precipitation may be carried on with precipitated. An impregnation with aluminium oxide gel may be carried on in this man ner. The abric 1s first soaked in ammonia, which may be done not only by the aid of a solution of ammonia but also by treating with NH,-gas, and then introduced into a solution of alum. The washing, drying and activating is carried out even here in known manner.

For successfully carrying out the divers impregnating methods it is aself evident presumption, that the fabric to be treated is deprived of the loading means or finish before being coated with the gel, which finish still adheres in consequence of the particular manner of manufacture, for instance glazing, stiffening or the like. If any soluble substances should be present in the fabric upon which the gel is to be precipitated, these substances might disturb or prevent the proper action if the gel precipitation is initiated too early.

I claim 1- a 1. Gas rotective material comprising a fabric havmg a substantially adherent coating of an active, gas absorbing, inorganic gel.

2. Gas protective material as claimed in claim 1, wherein the gel envelops the individual fibers constituting the threads of the fabric.

3. Method of producing a; gas protective material, which comprises the steps of impregnating the individual fibers of a piece of fabric with freshly prepared inorganic sols or gels, and activating the same on the fabric.

4. Method of producing a gas protective material, which comprises precipitating an active, gas absorbing, inorganic gel upon the individual fibers of a piece of fabric, drying said precipitate, and activating the same on the fabric.

5. Method of producing a gas protective material, which comprises the steps of soaking a fabric with one solution, and then introducing said soaked fabric into a second solution adapted to cooperate with the first said solution to form'a recipitate comprising an active, gas absor ing gel, then activating the gas absorbing gel on the fabric.

6. Method of producing a gas protective fabric which comprises the steps of soaking a fabric in a solution of alkali-silicate, transferring the saturated fabric into asolution of an acid chloride, washing said material, and then drying and activating the same.

7. Method as claimed in claim 3, wherein the finish is removed from the fabric before impregnation with the gel.

In testimony whereof I have signed my name to this specification.

GERHARD KARI. EM". HEINRICH STAMPE.