US2173242A - Process for treating fibrous material - Google Patents

Description

' Patented SepblQ, 1939 um'rau STATES PATENT OFFICE PROCESS FOR TREATING FIBBOUS Harman Howard A. Young, Westfield, N. 1., auignor, by mesne'aaignmentl, to United States Rubber Company, NcwYork, N. Y a corporation at New Jersey No Drawing. Application January 3, 1938,

Serial No. 183,091

SCIaims. -(L 91-ss terial from the bath by reason of the oppositely charged colloidal particles of treating material contacting the fibrous surface; The ratio of treating bath to fibrous material in these processes, however, is extremely high, ranging from :1 to 50:1 and over, commonly called in textile practice a long bath, while the concentration of colloidal treating material in .such treating baths is extremely low, ranging from a few hundredths of one percent to less than two percent. In othenprocesses of treating fibrous materials with a long bath, as with dilute latex, the rubber "particles are coagulated on the fibers by means of heat, or by the gradual addition of a coagulant to the bath. There are many disadvantages in using such large volumes of dilute bath. A large volume of dilute bath necessitates 39 the use of a much higher amount of protective agent for the equivalent degree of stability of a given amount of dispersed colloidalmaterial than 45 colloidal material to deposit upon the surface or the fibrous material and subsequently be rubbed oil by mechanical friction, and, in the case of fabrics, to show streaks, chafe marks, and socailed running marks and crows feet on the 50 finished material.

' not continuous and this is of a decided disadvantage in treating long lengths of fabric.

In other processes, the fibrous material may be treated with an amount of a latex composition 65 that is less than that which will cause wet satuping wet.

Further, such processes are ration of the fibrous material, that is, an amount which can be held by the fibrous material without permitting liquid to drain from the material when it'is hung up or draped, or an' amount less than that which would cause the material to be drip- The amount of latex composition which usually remains held in the fibrous material in such treatments, as where the fibrous ma-' terial is, passed through a bath of the latex composition and wrungor squeezed, as through roll- 1 ers, or where the latex is sprayed onto the fibrous -material, is from 40% to 250% of the weight of thefibrous material. In such processes, however, the rubber particles remain in dispersed condition in the latex which is held by the fibrous material until they are coagulated by some ex- .ternal influence, as by the drying of the latex held in the fibrous material, or by a chemical coagulation of the latex composition, as by pretreating the fibrous material with a latex coagu- 20 lant, or by passing the fabric with the absorbed latex through a separate coagulating bath, or by heating the fibrous material containing the latex composition in cases where the latex is heat sensitive, that is, where the latex is coagulable 25 by heat. In these processes where the rubber is coagulated from the latex that is held in the fibrous material as by drying, or bytreatment with a free coagulant, or by heating a heat 'sensitive latex composition, the rubber that is" deposited on the fibrous material becomes concentrated during the coagulating operation on the outer surfaces of the fibrous material, and the finished material may become stifi and boardy, and, in the case of fabrics, lose the fabric feel and appearance of untreated fabric.

According to thepresent invention, fibrous material is treated with an amount of a, latex composition which is less than that required for wet saturation of the fibrous material, and the col 40 loidal rubber particles are deposited onto the fibrous material without the aid of any external coagulating influences, thereby permitting the colloidal rubber particles to gradually deposit on the fibers evenly throughout the body of the fibrous material from the inside of the material so that the finished product while obtaining the advantages of the-rubber treatment, maintains the appearance and feel of untreated material.

In carrying out the process of the present invention, fibrous material, is treated with an amount less than that required for wet saturation of a latex composition which will deposit substantially all its rubber particles on the fibrous material under normally non-coagulative conditions for the latex composition. and thereafter allowing the fibrous material with its contained latex composition to rest until the dispersed rubber particles have deposited on the fibrous material. The amount of entrained or absorbed latex composition which will cause wet saturation of the fibrous material differs with different kinds of fibers and various types of fibrous material, but the ratio of the absorbed latex composition to fibrous material according to the present invention will range with various fibrous materials and depending on the amount of rubber desired to be deposited on the fibrous material, from .4:1 to 25:1, that is, the weight of the latex composition held in the fibrous material will be 40% to 250% of the weight of the fibrous material. The latex composition for treating the fibrous material should have a 3 to 30% solids concentration depending on the amount of latex composition caused to be absorbed by thefibrous material and on the amount of rubber desired to be finally deposited on the fibrous material. The latex composition which is absorbed in the fibrous material is made sensitive to the fibrous mat-- rial, that is, will deposit its colloidally dispersed rubber particles on the fibrous material under otherwise non-coagulative' conditions for the latex composition itself, by compounding the latex treating bath so that it contains a latex coagulant and sufficient protective so that it is itself stable under the conditions of treatment of .the fibrous material, but will deposit its rubber particles on the fibrous material when associated with the fibrous material. The amount of protective introduced into the latex treating composition need be but slightly more than that necessary to stabilize the latex treating composition in the absence of the fibrous material under the conditions of treatment of the fibrous material. The greater the amount of protective used over that necessary to merely protect the latex composition against coagulation in the absence oi the fibrous material by the added coagulating agent, the slower will be the deposition of the dispersed rubber particles from the composition onto the fibrous material when in' contact therewith. If the fibrous material is treated with the latex treating composition at room temperature and the fibrous material with the latex held therein is permitted to rest at room tem-' perature until the dispersed rubber particles have deposited on the fibers, the amount of protective agent in the latex composition need be only that amount or slightly more than that which is necessary to protect the latex composition itself at room temperature. If the fibrous material is treated with the latex composition at elevated temperature, then the amount of protective must be such that it will stabilize the latex composition in the presence of the added coagulant at such elevated temperature, otherwise the latex treating bath will coagulate before being absorbed into the fibrous material. Likewise if the fibrous material is treated with the latex treating composition at room temperature and allowed to rest at elevated temperaure, in order to speed up the deposition of the rubber onto the fibrous material, the amount of protective must again be such that the latex composition itself is stable at such elevated temperature, otherwise the rubber will not be allowed to deposit gradually on the fibers of the fibrous material but the latex composition will coagulate at the elevated temperature of the rest period and produce an uneven surface coagulation. Of course the treatment of the fibrous -material with the latex should be carried out under all other normally non-coagulative conditions for the latex treating composition, that is, without coagulation by outside influence, as for example, drying, or the presence of free coagulant on the fibers, or passing of the fibrous material impregnated with the latex treating bath through a coagulant medium.

I have developed a theory for my invention which explains the sensitivity to a fibrous material of an otherwise noncoagulating latex composition, and this I am setting forth with the idea of clarifying the process, but without the intention of making the invention in the case dependent upon the correctness of this theory. I believe that when a fibrous material holds its entire treating bath, that is, contains an .amount less than its wet saturation," of a latex composition of a solids concentration of dispersed particles as high as 3 to 30% and contains a coagulant and protective in accordance with the present invention, the fibrous material gradually absorbs the protective from the latex composition and causes a deposition of the colloidal rubber particles which are then in the presence of a coagulant but are no longer protected from the coagulant by the protective which has been absorbed by the fibrous material, so that there is gradually built up with the absorption by the fibers of the protective agent, a deposition of the no longer protected rubber particles. It has been found that the coagulant that is introduced into the latex composition and against which the .colloidally dispersed rubber particles are protected in the absence of the fibrous material maybe an alkaline or acid coagulant so that the deposition of the dispersed rubber particles on the fibrous material is not necessarily dependent on any type of charge on the colloidal rubber particles or on the fibrous material.

Various types of fibrous materials, such as woven, knitted, punched, or felted fabrics, yarns, rovings, cords, skeins, and .webs such as waterlaid felts from a paper making machine or bats of fibers from a Garnett or carding machine, may

be treated according to the present invention. Various fibers, as of wool, silk, cotton, viscose or acetate rayon, linen, cellulose and the like may be used and these may be undyed, mordanted, dyed or otherwise treated so long as they are not associated with free coagulant which in the absence of the fiber would itself produce coagulaotherwise treated as desired, as by vulcanization,

and which may be in a normal, diluted, concentrated or purified condition prduced by methods well known in the art.

Various examples of the treatment of different fibrous materials with latex compositions protected with various known stabilizers and containing a coagulant according to the present invention are set forth below, but these are merely exemplary of the invention and are not intended to be limitations thereon. Common latex protectives that may be used are proteins, gums, soaps,

vegetable mucilages, saponin, starch, and certain v salts oi carboxyl (it-0001b, 'sulphonic (RF-Bonn), sulphinic (R SO:M), or phenolic groups or of ethereal sulphuric (R-OM) (RQSOaM) radicals, where the R may have a straight chain or ring structure and may contain substituent halogen, amino, nitro. or hydroxyl groups. Other organic chemicals are well known protectives as certain benzene-sulphonic acids, their homologues and substitution'prodl0 ucts, naphthoic acids, aliphatic-aromatic-acids,

derivatives of hydro-aromatic series of acids. phenylglycine and derivatives.

. In order to better understand the invention, the following illustrative examples are included.

7 In these examples, the selected fabric was passed through the latex treating bath so that it became thoroughly wetted by the latex, and the desired amount of latex was removed by passing inthe flat through squeeze rolls. The amount of latex composition remaining absorbed in the desired period of time, which in practice canecon- 0 veniently be anything up to 60 minutes during which time the'dispersed particles of rubber deposited in and upon the fibers. The duration 'of this rest treatment for depositing a desired proportion, or all, of the dispersed rubber particles,

can 7 be governed by the composition of the bath, commonly by the concentration of the latex composition and the amount of protective used over that necessary to prevent coagulation of the latex in the presence of the coagulant contained 40 therein but in the absence of the fibrous material.

In practice, however, it is a simple matter to determine the amount of rubber not deposited from the latex composition by squeezing a part of the fabric at time intervals by hand and noting the characteristics of the expressed liquid, such as turbidity, or by rinsing samples of the fabric and noting the degree of turbidity ofthe rinse water. Elevated temperatures, which in the absence of the fibrous material, would not cause coagulation of the latex composition, may be used and thus speed up the deposition of solids from the latex onto the fibrous material. After the desired amount of ruhber'has deposited from the latex onto the fibrous material, the thus treated material may be washed, dried, the rubber deposit vulcanized if desired, and the material finished. There is an additional distinct-advantage here over methods of treatment where the entrained latex must be dried to form the deposit on the fibrous material and where the thus dried material is subsequently washed and redried. In such practice two dryings are necessary whereas according to the present invention only one drying operation need be performed due to the deposition of the rubber onto the fibers in the wet condition and the consequent possibility of washingthe treated'material without a preliminary drying for setting the same. Formlc acid is the coagulant used in compounding the latex treating baths in the following examples because it is a volatile acid, but other acids, namely acetic,

lactic, tartaric, phosphoric, hydrochloric, and

sulphuric acid have successfully been used, as well as various acidic and basic coagulating salts. J

C, lnl'mplel The latex compound for use in preparing the treatingbath was made up as follows:

' weight Rubber (as 60% centrifuged ammonia pre served latex) Potassium hydroxide (as 25% aqueous solution) i 2 1 Glue (as 25% aqueous solution) .4 Aquarex D (as 10% aqueous solution)..- 1.25 Paste (as 35% aqueous paste): ,5 Mercaptobenzothiazole Dimethylammonium dimethyl dithio- 15 carbamate Solubilized casein 4 Colloidal sulphur 2 Zinc oxide 2.5

BLE l 5 so Water to final total solids of 40%. r

The aqueous solutions of potassium hydroxide,

glue and Aquarex D were added to the centrifuged latex and to this was added the remaining materials in the form of a 35% aqueous paste, after which the wholelwas diluted with water to a final total solids of 40%. The "Aquarex D is a stabilizer having the composition, monosodium sulphate ester of one-half lauryi and one- 30 half myristalalcohol. The mercaptobenzothiazol M and dimethylammonium dimethyl dithiocarbamate are vulcanization accelerators. 'BLE is the trade name of an antioxidant which is a condensation product of acetone and diphenylamine. The casein .in the above paste was solubilized by means of a small amount of borax and sodium fluoride in a manner well known in the art.

A latex treating bath of the composition set forth below was made up from the above compound by diluting with water and adding a coagulant after the addition of an amount of protece tive or stabilizer sufficient to" prevent coagulation of the treating bath by the added coagulant. If desired, the entire amountof'stabilizer, with or without the acid, maybe added in compounding the original latex, and merely water, or water and acid as the case may be, mixed with the latex compound to produce the treating bath.

Wool flannel fabric was run through the above latex treating bath and squeezed through rollers so that it contained about of its weight of the treating bath, that is, the so-called bath-togoods ratio was approximately 12:1. The fabric with the thus absorbed latex composition was al- Bil lowed to stand at room temperature for 60 min utes, in whichtime substantially all the rubber as deposited on the fabric as shown by a clear rinse.

The fabric after rinsing anddrying showed a gain in weight of 12.2%. Sulphano "is the trade name of a stabilizer which is a snlphated fatty alcohol. 7n

Example 2 In this case, the latex compound of Example 1 was made up into atreatingbath usinga different rotective from the Sulphanol" used in m Solidsby Example 1. The treating bath in this case had the toilowing composition:

Parts by weight Solids of the latex compound of Example 1-- 10' Nopalcol No. 2"

Formic acid 5 Water- 79.7

Wool flannel fabric was run through the .above latex treating bath and squeezed through rollers so that it contained about of its weight of the treating bath, that is, the bath-to-goods ratio was approximately .85:1. The thus treated fabric was allowed to stand at room temperature for 15 minutes, in which time substantially all the rubber deposited on the fabric, as shown by a clear rinse. The fabric after rinsing and drying showed a gain in weight of 8.5%. "Nopalcol No. 2 is the trade name of a stabilizer which is believed to be a sulphated oil.

Example 3 Fabrics composed of fibers of more than one kind may be treated according to the present invention. In this case a paper machine woven felt with a cotton warp and a wool filling was treated with a latex composition made from the latex compound of Example No. 1. In preparing the treating bath, the same stabilizer, Aquarex D", was used to prevent coagulation on addition of the coagulant that was used in compounding the original latex. The composition of the treating bath in this case was as follows:

Parts by weight Solids of latex compound of Example 1 12 "Aquarex D" 2 Formic acid 12 Water 74 The paper machine felt was run through the above treating bath and squeezed through rollers so that it contained about 130% of its weight of the treating bath, that is, the bath-to-goods ratio was approximately 13:1. The thus treated felt was allowed to stand at room temperature for 60 minutes with no sensible reduction of water content, in which "time substantially all the rubber deposited on the fabric, as shown by a clear rinse. The fabric after rinsing and drying showed a gain in weight of 16.1%.

The treatment of other fibrous materials than wool is illustrated in Examples 4 to 6.

Erample 4 Silk fabric was treated according to the present invention with a treating hath made. from the latex compound of Example 1 having the following composition:

' Parts by weight Solids of latex compound of Example 1' 10 Aquarex D"; .4 Formic acid .5 Water 89.1

The silk fabric was run through the above treating bath and squeezed through rollers so that it contained about 150% of its weight of the treating bath, that is, the bath-t -goods ratio -was approximately 15:1. .The fabric with the contained latex was allowed to stand at room temperature for 20 minutes, in which time substantially all the rubber deposited on the fabric, and the fabric after rinsing and drying showed again in weight of 15.2%.

Example 5 A cotton fabric was run through the treating bath of Example 4 and squeezed through rollers so that it contained about of its weight of the treating-bath, that is, the bath-to-goodsratio .was approximately .95: 1; The thus treated fabric was allowed to stand for 20 minutes at room temperature. After rinsing and drying the fabric showed a gain in weight of 8.5%. The rinse was slightly hazy, and in the 20 minute period approximately 90% of the rubber in the treating bath had deposited on the fabric.

Example 6 In this example, a so-called immunized cotton fabric was runthrough the treating bath of Example 4 and squeezed through rollers sothat it contained about of its weight of the treating bath, that is, the bath-to-goodsratio was approximately 1:1. The thus treated fabric was allowed to stand 20 minutes at room tem-' perature in which time substantially all the rubber deposited on the fabric as shown by a clear rinse. The fabric after rinsing and drying showed a gain in weight of'9.6%.

Various latex treating compositions can. of course, be used, and different latex compounds from those used in Examples 1 to 6 are used for preparing the treating baths of Examples 7 and 8. In addition, these examples show the treatment of other materials than those treated in Examples 1 to 6.

Example 7 carbamate 1 Zinc oxide ,5 Agerite Alba .5 Colloidal sulphur 5 UBIE" I -5 Gum arable 1 Gum arabic (as 10% aqueous solution) 1 Water to final total solids of 35%.

The stabilizing solutions of gum arabic and Aquarex D" were added to the latex and to this was added the separately prepared paste of curing ingredients- To this was added more gum arabic solution as shown by the above formula and'the whole was diluted with water to 35% solids content. Darvan is the trade name of a stabilizer sold by R. T. Vanderbilt Co. which is believed tobe a sulphonated naphthalene derivative, The

tetramethyl thiurammonosulphide and piperidinium p'entam'ethylene dithiocarbamate are vulcanization accelerators. Agerite Alba" is the trade name of an antioxidant made by R. T. Vanderbilt Co. and which is said to be a complex phenolic compound containing carbon, hydrogen andoxygen.

The treating bath made up from the abovelatex had the following composition:

Parts by weight Solids of above latex compound 10 Vultamol" 1.3 Formic acid 1.7 Water 87 The rayon fabric was passed through the above pro arraase treating bath and squeezed through rollers so that with the entrainment of this competition it contained about 80% of its weight of the treating bath that is, the bath-to-goods ratio was apately .8:1. The thus treated fabric was allowed to stand at room temperature for 20 minutes, in which time substantially all the rubber deposited on the fabric as shown by a clear rinse. After rinsing and drying, the fabric showed a gain in weight of 8.2%. Vultamol is the trade name of a protective or stabilizer which is believed to be a sulphated oil.

Example 8 In this example, a cotton fabric which was tanned was used. The-cotton was tanned by soaking the fabric for two hours in a 1% tannic acid solution at 140 F.,' wringing, and drying; then soaking for one-half hour in 5% tartar emetic solution, rinsingso that it contained no free coagulant, wringing and drying.

The latex compound from which the treating bath was prepared was made up as follows:

. Water to final total solids of 35%.

The Aquarex D solution was added to the latex for stabilizing purposes and to this was added the separately prepared paste of curing ingredients.

The whole was then diluted with Water to 40% solids content. The zinc-'dimethyl dithiocarbamate is a vulcanization accelerator.

The treating bath was prepared from the above compound to have a composition as follows:

. Parts by weight Solids of above latex compound l0 Aquarex D .2 Formic arid 15 Water 74.8

I The tanned. cotton fabric was passed through the above treating bath and squeezed through rollers so that it contained about of its weight of the treating bath, that is, the bath-to goods ratio was approximately 37:1. The fabric with the thus contained latex composition was allowed to I stand at room temperature for 20 minutes, in which time substantially all the rubber deposited on the fabric. After rinsing and drying, the fabric showed a gain in weight of 6.9%.

The application of the present invention to artificial dispersions of rubber and synthetic rubber like materials is illustrated in Examples 9 and 10.

' Example 9 In this case the treating bath was made from an artificial dispersion of crude rubber dispersed on rosin soap. The formula for the dispersion was as follows:

Water to final total solids of 50%,

The dispersion was made up in the usual manner of mixing the rosin and sodium hydroxide dispersing materials into the crude rubber after plasticialng, andadding water until an inversion of phase, wherein the rubber became dispersed inthe water, and adding further water to dilute to 50% total solids content.

The treating bath was made up from the above dispersion compound as in the previous examples by diluting the water and acidifying in the presence of the added stabilizer. The composition of the treating bath was as follows:

- Parts by weight Solids 01 above dispersion compound 10 Aquarex D" -1 2 Formic acid 20 Water 68 Silk fabric was run through the above treating bath and squeezed through rollers so that it contained about of its weight of the treating bath, that is, the bath-to-goods ratio was approximately 12:1. The thus treated fabric was allowed to stand at room temperature for-20 minutes, in which time substantially all the rubber deposited on the fabric. The fabric after rinsing and drying showed a gain in weight of Example Ii) In this case a wool fabric was treated with an aqueous dispersion of chloro-Z-butadiene 1-3. Commercial Duprene Latex Type 50 sold by E. I. du Pont de Nemours 8: 00., Inc., and which is an aqueous dispersion of polymerized chloro-2- butadiene, 1-3 or so-called chloroprene was used. This dispersion is stated by the manufacturer to have the following composition:

, Parts by weight Polymerized chloroprene 45 Antioxidant-Neozone L.- 0.56 Sodium olea 0.9 Aqua, ammonia 1 Water 52.54

The composition of the Neozone L is not known.

A treating bath was made up from the Duprene Latex Type'50 according to the following The wool fabric was passed through the above 1y 1.1:1. The thus treated wool fabric was allowed to stand at room temperature for 20 minutes, in which time substantially all the dispersed solids of the treating bath deposited on the fabric. The fabric after rinsing and drying showed a gain in weight of 10.6%.

The above, examples clearly illustrate the present invention and it will be obvious to those smiled in the art that various other treating baths than those illustrated in the above examples and stabilized against coagulation in the absence of the fabric and sensitized to deposition in the presence of fibrous materials, may be developed using the principles of the present invention. In view of the many changes and modifications that may be 250% or the weight of the fibrous material and which'is less than that required for "wet saturation oi the fibrous material so that the fibrous material holds its entire treating bath, the treating bath being capable of depositing on the fibrous material in which it is held substantially all its dispersed rubber particles under normally non-coag'ulative conditions for the latex composition, and maintaining the treating bath in the fibrous material under normally non-coagulative conditions for the latex composition until the desired amount of rubber has deposited on the fibrous material,

2. The process which'comprises associating fibrous material with a latex composition having a 3% to 30% solids concentration, causing the fibrous material to entrain therein an amount of said latex composition which ranges from 40% to 250% of the weight of the fibrous material and which is less than that required for "wet saturation of the fibrous material so that the fibrous material holds its entire treating bath, the treating bath being capable of depositing substantially all its dispersed rubber particles under normally non-coagulative conditions for the latex composition on the fibrous material in which it is held, and maintaining the treating bath in the fibrous material under normally non-coagulative conditions for the latex composition until substantially all the rubber has deposited on the fibrous material.

3. The process which comprises associating fibrous material with a latex composition having a 3% to 30% solids concentration, causing the fi-,

brous material to entrain therein an amount or said latex composition which ranges irom 40% to 250% or the weight of the fibrous material and which is less than that required for "wet saturation of the fibrous material so that the fibrous material holds its entire treating bath, said latex composition containing a coagulant and an amount of protective that stabilizes the latex composition in the absence oi the fibrous material but not in the presence of the fibrous material, the treating bath being capable of depositing on the fibrous material in which it is held substantially all its dispersed rubber particles under non-coagulative conditions for the latex composition itseli', and maintaining the treating bath in the fibrous material under non-coagulative conditions for the latex composition itself until the desired amount of rubber has deposited on the fibrous material.

4. The process which comprises associating fibrous material with a latex composition having a 3% to 30% solids concentration, causing the fibrous material to entrain therein an amount of said latex composition which ranges from 40% to 250% of the weight of the fibrous material and which is less than that required for "wet saturation of the fibrous material so that the fibrous materialholds its entire treating bath, sa d latex composition containing a coagulant and M" amount or protective that stabilizes the latex composition in the'absence oi the fibrous material but not in the presence of the fibrous material, the treating bath being capable oi depositing on the fibrous material in which it is held substantially all its dispersed rubber particles under noncoagulative conditions for the latex composition itself, and maintaining the treating bath in the fibrous material under non-coagulative conditions'ior the latex composition itseli until substantiallyaall the rubber has deposited on the i1- brous material.

5. The process which comprises associating fibrous material with a latex composition having a 3% to 30%solids concentration, causing the fibrous material to entrain therein an amount 01' said latex composition which ranges from 40% to 250% of the weight of the fibrous'material and which is less than that required for "wet saturation" or the fibrous material so that the fibrous material holds its entire treating bath, said latex composition containing a coagulant and an amount of protective that stabilizes the latex composition at room temperature in the absence of the fibrous material but not in the presence of the fibrous material, the treating bath being capable of depositing on the fibrous material in which it is held substantially all its dispersed rubber particles at room temperature and in the absence or free coagulant on the fibrous material, and maintaining the treating bath in the fibrous material at room temperature in the absence of tree coagulant on the fibrous material until the desired amount oi! rubber has deposited on the fibrous materiaL- 6. The process which comprises associating fibrous material with a latex composition having a 3% to 30% solids concentration. causing the fibrous'material to entrain therein an amount 01' said latex composition which ranges from 40% to 250% of the weight of the fibrous material and which is less than that required for "wet saturation of the fibrous material so that the fibrous material holds its entire treating bath, said latex composition containing a coagulant and an amount of protective that stabilizes the latex composition at room temperature in the absence the fibrous material but not in the presence 01' the fibrous material, the treating bath being capable of depositing on the fibrous material in which it is held substantially all its dispersed rubber particles at room temperature and in the absence oi free coagulant on the fibrous matrial, and maintaining the treating bath in the fibrous material at room temperature in the absence of \iree coagulant on the fibrous material until substantially all the rubber has deposited on the fibrous material.

'7. The process which comprises associating fibrous material with a latex composition having a 3% to 30% solids concentration, causingthe fibrous material to entrain therein an amount of said latex composition which ranges from 40% to 250% of the weight of the fibrous material and wh ch is less than that required for "wet saturation" of the fibrous material so that the fibrous material holds its entire treating bath, said latex composition containing a coagulant and an amount 01 protective that stabilizes the latex composition at elevated temperature in the absence of the fibrous material but not in the presence of the fibrous material, the treating bath being capable of depositing on the fibrous material in which it is held substantially all its dis- 76' 250% of the weight of the fibrous material and which is less than that required for "wet saturation of the fibrous material so that the fibrous composition at material holds its entire treating bath, said latex composition containing a coagulant and an amount of protective that stabilizes the latex sence of the fibrous material but not in the presence of the fibrous material, the treating bath being capable of depositing on the fibrous material in which it is held substantially all its dispersed rubber particles at elevated temperature and in the absence of free coagulant on the fibrous material,. and maintaining the treating bath in the fibrous material at elevated temperature without drying and in the absence offree coagulant on the fibrous material until substantially all the rubber has deposited on the fibrous material.

HOWARD A. YOUNG.

elevated temperature in {the ab-