US3359060A - Dry heat treatment included in conventional wet processing of wool-acrylonitrile blended fabrics to effect setting of acrylonitrile component - Google Patents

Description

D 19 957 A. D. ROSENBERG E AL DRY HEAT TREATMENT INCLUDED IN CONVENTIONAL WET PROCESSING OF WOOL'ACRYLONITRILE BLENDED FABRICS TO EFFECT SETTING OF ACRYLONITRILE COMPONENT Filed Oct. '2, 1963 FIG.1.

COMPRESSION m w Y wm N mm o an m m MM D l I l l l l ll mN 7 m A u m m W W s M E T B lllll wUmOumdmIm 2 G H IT United States Patent C 3,359,060 DRY HEAT TREATMENT INCLUDED IN CONVEN- TIONAL WET PROCESSING OF WOOL-ACRYLO- NITRILE BLENDED FABRICS TO EFFECT SET- TING F ACRYLONITRILE COMPONENT Arthur David Rosenberg, London, and Brindley Jack Brown, Altrincham, England, assignors to Chemstrand Limited, London, England Filed Oct. 7, 1963, Ser. No. 314,445 7 Claims. (Cl. 8--115.7)

This invention relates to the finishing of textile fabrics. Woven and knitted textile fabrics of the kind comprising a combination of wool yarns and yarns having a basis of polyacrylonitrile or copolymers of acrylonitrile with other polymeric materials are known to behave less satisfactorily in some respects than 100 percent Wool fabrics during Wear, particularly when made into outer-wear garments such as suits, skirts or dresses. The invention is particularly concerned with the aspect of wear performance of fabrics composed of blends of polyacrylonitrile and wool involving garment creasing which is normally assessed by crease-recovery angles. Creasing in relation to the present invention also includes the inter-related phenomena of buckling, shear and drape.

It is an object of the present invention to provide a method of finishing textile fabrics of the kind referred to which enhances and optimizes the resilience and recovery of the fabrics.

3,359,060 Patented Dec. 19, 1967 ing operation in a hot dilute alkaline soap solution, rinsing the scoured fabric in a hot aqueous solution, gradually cooling the fabric after rinsing, treating the cooled fabric in a hydro-extractor and drying the fabric; thereafter subjecting the fabric to hot-air treatment at a temperature in the range of 195-200 C. for a period of up to 25 seconds to set the polyacrylonitrile component of the fabric, cooling the fabric and rinsing it in a hot solution of a softening agent, allowing the rinsed fabric to cool gradually and thereafter treating the cold fabric in a hydro-extractor and drying the fabric, blowing steam onto the dry fabric and finally applying to the fabric a dry finishing treatment.

In order to clearly understand the nature of the present invention and the improvements resulting from the treatment of fabrics in accordance therewith, experiments have been made to determine certain mechanical properties of specimen fabrics, such as crease-recovery, blending stiffness and shear behaviour. Details of these experiments are set out hereinafter.

Five fabrics incorporating varying differences in the percentages of wool and Acrilan (registered trademark), the fabric sett, the denier of the Acrilan and the yarn count and twist were subjected to the normal worsted finishing routine designated A and to the finishing routine in accordance with the invention and designated B. Constructional details of the fabrics are set out in Table I below.

TABLE I.CONSTRUCTIONAL DETAILS OF FABRICS Sett in loom Yarn Yarn twist Weight Fabric Composition Acrilan count (t.p.i., per Weave, No. Denier Ends Picks (W0) single and sq. yd., twill per per twofold) oz. inch inch 100% Wool 54 53 2/368 12-13 7. 7 2,2 100% Acrilan 3 54 53 2/368 12-13 7. 7 2/2 do 5 54 53 2/36s 12-13 7. 7 2/2 50% Acrilan, 50% wool 3 54 53 2/365 12-13 7. 7 2/2 do 3 58 57 2/28S 12-13 9. 3 2/2 As a result of extensive experiments it has been found that by adopting a modification of the conventional finishing routine, which modification consists basically in incorporating in the finishing procedure a dry heat treatment and washing off process, the crease recovery of fabrics of the kind referred to is greatly improved and possess a recovery performance comparable to all-Wool and wool/ polyester fabrics. The fabrics so treated are soft, supple, and have a Wool-like handle. It has been ascertained by experiment that conventional wool-finishing procedures have little or no effect on the polyacrylonitrile component of blended fabrics of the kind referred to. The invention has therefore been devised with a view to optimizing the inherent fibre resilience characteristics of the polyacrylonitrile components of such fabrics.

According to the present invention there is provided a method of finishing textile fabrics of the kind referred to, comprising the steps of subjecting the fabric to a scour- The fabrics were selected so that direct comparisons could be made between an all-wool fabric and fabrics containing Acrilan in the same construction. Fabrics Nos. 2 and 3 were chosen to demonstrate the improvement of fabrics consisting of 100 percent Acrilan resulting from the finishing treatment according to the invention and thus to show that the Acrilan component of the blend is affected by such finishing treatment. Fabric No. 4 was chosen to show that, although it was satisfactory when finished by the conventional worsted finish, it was further improved by the process according to the invention. Fabric No. 5, although it is constructed too closely by Laws formulae, is, even so, much improved when finished in accordance with the invention.

Some typical fabrics consisting of blends of polyester and wool were subjected to some of the tests described hereinafter and the constructional details of these fabrics are set out in Table II below.

TABLE TL-CONSTRUC'IIONAL DETAILS OF FABRICS Finished sett Warp and Ends Picks Yarn weft twist Weight Fabric Composition per per count (single and per sq. Weave No. inch inch (W0) tuofold) yard polyester, 45% wool 52 44 2/34s 11-13 4.8 Plain. 67 59 2/36s 14-15 7. 1 2/2 twill.

55% polyester, 45% wool 82 52 2/32s 13-15 8. 6 Cavalry twill.

In the finishing treatment according to routine A the undyed loomstate fabrics were subjected to the finishing treatment conventionally applied to worsted fabriw.

Finishing routine A involved the steps of (a) crabbing (b) scouring (c) drying and (d) blowing. In the crabbing step the fabrics were wound onto a roller which was then rotated in boiling water for a period of 3 minutes. The fabrics were then wound onto another roller and the boiling operation was repeated. The fabrics were then twice wet steamed on two separate rollers, the time of steaming in each case being five minutes; The fabrics were then vacuum cooled. The scouring liquor consisted of a solution of 3 percent soap and 1.5 percent soda based on the weight of the fabric. The fabrics were then stenterdried at a temperature of 210 F. Thereafter each fabric was blown for two minutes at a steam pressure of 20 lbs. per square inch.

Finishing routine B wrich is in accordance with the present invention involved scouring the fabrics in a dolly scouring machine in a solution of 3 percent soda ash based on the weight of the fabric at a temperature of approximately 45 C. for a period of 25-30 minutes. The fabrics were then rinsed in Water for 20 minutes firstly at a temperature of about 45 C., the temperature being gradually reduced to room temperature to cool the fabrics. The fabrics were then subjected to treatment in a hydro-extractor and dried on a stenter drying machine at a temperature of about 100 C. Heat treatment of the fabrics was then effected at a temperature of about 195-200 C. by blowing with hot air for a period of up to 25 seconds and allowing the fabric to cool. Rinsing of the fabrics was then carried out in a winch in a 0.5 percent solution of a cationic wetting agent, e.g. Sapamine WL, based on the weight of the fabric at a temperature of about 40-45 C. The fabrics were thereafter cooled gradually, treated in a hydro-extractor and dried at a temperature of about 100 C. on, for example, a stenter drying machine. Steam at a pressure of 20 lbs. per square inch was then blown onto the fabrics for a period of up to 2 minutes, care being taken to ensure that the fabrics were cold before removal from the machine. Finally, the fabrics were given a dry finishing treatment by steaming, brushing, cropplilng, further steaming, followed by pressing between paper s eets.

Crease recovery measurements were made on all the finished fabrics on a Shirley Creasometer. Samples measuring 5 x 2.5 cm. were cut from each fabric, 5 in the warp direction and 5 in the Weft direction. Before testing, the samples were conditioned for 24 hours in an atmosphere maintained at 65 percent relative humidity and at a temperature of 20 C. The samples were creased for minutes with a load of 2 lbs., the angles of recovery being measured after five minutes. The results of the crease-recovery measurements are set out in Table III below.

values of over 150 when measured by this technique. It will be evident from the data given in Table III thatwhen fabrics are finished in accordance with routine A, i.e. the standard worsted finishing routine, fabrics 1 and 4 have very good crease-recovery properties. The recovery angles of the tightly sett Acrilan/wool fabric No. 5 emphasise the need to avoid oversetting fabrics made from Acrilan and wool. The crease-recoveries of all the fabrics containing Acrilan are improved by the finishing process in accordance with the invention and it will be observed that the Acrilan component of the fabric is aifected by the heat-treatment because the recovery performance of the 100% Acrilan Fabrics Nos. 2 and 3 are greatly improved.

A crease-recovery test provides limited information and may well be supplemented by tests for recovery from less drastic treatment such as wrinkling. Recovery from light wrinkling and buckling as described by B. Dahlberg in the Textile Research Journal 1961, vol. 31, page 94, with an estimate of the energy lost during loading and unloading cycles, may be determined. Fabric samples, clamped between two jaws, are compressed in the plane of the fabric. The fabrics buckle and the recovery from buckling and the energy lost during compression cycles may be determined. For textile purposes, two types of buckling are important, that of a flat piece of material (plate buckling) and that of a cylindrical sleeve (shell buckling). The recovery of the fabrics from both plate buckling and shell buckling was measured under standard conditions, whilst recovery from plate buckling was measured at a higher temperature and relative humidity. The buckling tests were carried out on an instrument attached to an Instron machine which essentially consists of two plane jaws (for plate buckling) or two corrugated jaws (for shell buckling), one clamped to the load cell and the other, to the moving crosshead. The separation of the jaws was one inch apart. The procedure was as follows. A fabric specimen 10 x 11 cm. was clamped between the jaws and the bottom jaw was then moved upward 0.4 inch, i.e. a compression of 40%. The specimen was first compressed and was then buckled after the compressional load exceeded 50%. The bottom jaw was then lowered to its original position, the fabric being thereby forcibly recovered. The fabric was again compressed and during the entire cycle the load-deformation curve was registered on the Instrom recording chart. A typical curve is shown on FIGURE 1 of the accompanying drawings. The various portions of the curve illustrated in FIGURE 1 are as follows:

(1) Compression curve-controlled deformation.

(P Buckling load-point at which the fabric buckles.

(2) Buckling curve-uncontrolled deformation.

(P Buckling load at 20% compression (i.e. half the total compression.

TABLE IIL-CREASE-RECOVERY ANGLES OF FABRICS Finished accordin Finished accordin Flaggic Composition to Routine A g to Routine B g Warp Welt Warp Weft 1 100% wool 158 2 100% 3 denier Acrilan. 125

3. 100% 5 denier Acrilan 129 it; 50%dAcr1lan, 50% W001. 150

0 141 6 55% polyester, W00 141 7 polyester, 50% wool.. 158 8 polyester, 45% wool 156 Many crease-recovery measurements have shown that suiting fabrics with crease-recovery angles of 150 and above generally give satisfactory performance in wear, although these figures do not always characterise the subsequent performance in wear. Many Acrilan/ worsted and (3) Recovery curve.

(4) Compression cycle repeated.

The area under the curve A, B, C, D, designated 0c, is proportional to the energy used in the compression. The area under the curve F, E, C, D (7) is proportional most wool and wool/polyester fabrics have recovery to the energy recovered, and the area under the curve F,

Finished according to Routine B 2790 l a 1B67 m n v. w a mm nd V. EC 4269 n t R 6856 9 D. O f r e a P W 9313 43 6 R 6677 e tw w we mw MW 2001 R p 7mm? m Weft but are slightly higher than those of the oversett Acrilan/ wool fabric No. 5.

Percent Energy lost in cycling Warp Weft

TABLE IV.PLATE BUCKLING TESTS Finished according to Routine A Percent Recovery Warp Composition Fabric No.

G, C, D ([3) is proportional to the energy required to compress the specimen a second time. The percentage re- 55% polyester, 45% wool All the fabrics incorporating Acrilan are considerably improved after being finished by Routine B, i.e. in accordance with the present invention. Fabrics Nos. 2 and 3 consisting of 100% Acrilan exhibit extremely high improvements, while the properties of the two Acrilan/ wool fabrics Nos. 4 and 5 are similarly d and it is evident that garments made from these fabrics will covery from buckling may be expressed as Another way of assessing the recovery potential of a sample fabric is to measure the energy lost between the first and second compression cycles. Clearly, fabrics which lose little energy have excellent recovery properties.

per-

Weft

SJLDMU 1212 Weft improve tests set out above Percent Energy lost in cycling Warp -containing fabrics gid in a warm,

tute 1960, vol.

Percent Energy lost in cycling Warp buckling Weft jected to shell buckling tests Weit Finished according to Routine B Percent Recovery Warp , moist atmosphere than under stand- Finished according to Routine B Percent Recovery Warp Weft

ghtly set fabric No. S is the least satisfactory. bric stiffens and becomes more ri Weft form very well. The plate were performed under standard conditions. Plate buckling tests were also carried out under warmer and more hum of 90 F. The results of these tests are set out in Table V below.

Percent Energy lost in cycling Warp From the data shown in Table V it will be observed that the recoveries of the wool and Wool ard conditions, as would be expected. The 100% Acrilan fabrics Nos. 2 and 3 are not affected to the same extent. Again, the ti This fa Abbott in the Journal of the Textile Insti 51 T1384.

The fabrics were also sub and the results thereof are set out in Table VI below.

Percent Energy lost in cycling Warp conditions at 90% relative humidity and a temperature Weft are lower in a warm moist atmosphere in a manner similar to that noted Welt Finished according to Routine A Percent Recovery Warp TABLE VI.SHELL BUCKLLNG TESTS Finished according to Routine A Percent Recovery Warp TABLE V.PLATE BUCKLING TESTS (ELEVATED CONDITIONS) 0 6 8 5 4 &7 63354 55 The percentage energy lost during compression cycles can be expressed as:

From the data set out in Table IV below it will be seen that, when finished by the process according to Routine A, i.e. the standard worsted finishing process, fabrics No. 1 (100% Wool) and No. 4 (50% Acrilan/ 50% wool) have the best recovery properties, the allwool fabric showing the highest recovery, while the Acrilan/ wool fabric has the lowest energy loss in cycling. The recovery figures of the wool/ polyester fabrics Nos.

6, 7 and 8 are lower than those of fabrics Nos. 1 and 4 From the data set out in Table VI it will be seen that the results of the shell buckling tests are approximately the same as those obtained from the plate-buckling and crease recovery tests and therefore confirm that the recovery performance of fabrics containing Acrilan is enhanced by the finishing process in accordance with the present invention. The performance of fabric -No. 4 (50% Acrilan and 50% wool) when finished by Routine B, is slightly better than that of fabric No. 1 (100% wool) and is therefore a fabric that behaves excellently. It is apparent, however, that all the fabrics recover less efficiently from shell buckling than from plate buckling. The deformation of a shell structure is highly complex and the lower recovery values are indicative of the poorer recovery from wrinkling of, for example, the sleeves of a jacket in comparison with that of other parts of a garment.

Levels of crease-resistance below which fabrics are considered poor can be established although they are necessarily arbitrary. The 100% wool fabric No. 1 and the various polyester/wool fabrics Nos. 6 to 8 perform very well. Likewise, the Acrilan/wool fabrics finished in accordance with the invention are excellent since their recovery properties are similar. Suitably constructed Acri- Textile Research Journal, vol. 3 1, 1961, at page 87. Rectangular fabric samples measuring 11 x 11 cm. were clamped between two vertical rods which can move in opposite, linear and parallel directions by means of an attachment to an Instron machine. This produces the r quired shearing action. When the crosshead is moved upwards a shearing force of 3.3 g./cm. is applied. The angle of shear formed by the shear force is recorded on the Instron chart. Each test consists of a cycle in which the fabric is sheared in both directions. A typical shear curve is illustrated in FIGURE 2 of the accompanying drawings. The force and deformation are zero at A and the force then increases to the limit of T at the point D with a constant rate of deformation. The motions of crosshead and chart are then automatically reversed and the force increases to T at the point F, passing zero at E. After the second reversal, the force again passes zero at the point G. The shear angle, through which the sample has been deformed by the application of force, is measured from the diagram, being proportional to one-half of the distance I-H. The shear modulus is calculated by dividing the shear stress by the shear angle. Table VII below sets out the shearing properties of fabrics Nos. 1 to 5.

TABLE VII.SHEARING PROPERTIES OF FABRICS Ian/Wool fabrics, for example No. 4 are good when given normal worsted finishes, but they are greatly improved when finished in accordance with the invention. The improvements are permanent because the fibres are stabilised in relaxed configurations in the fabrics.

The handle of 100% Acrilan or Acrilan/wool fabrics finished in accordance with the invention is markedly improved, being more wool-like, softer and supple. Various tests have been carried out to determine precisely the changes that were obtained. The shearing and bending moduli of the fabrics were measured because a decrease in these moduli obtained by the use of the finishing process according to the invention indicates an improvement in the softness and draping characteristics of the fabrics.

A fabric is sheared by the action of a couple in the plane of the fabric and the shearing characteristics of fabrics are of importance in relation to fabric formability and handle. Soft fabrics shear readily, while stiff fabrics shear only slightly when subjected to the same shearing force. Hence, soft fabrics have larger shearing angles and where:

b:bending stiffness p=applied load (at 20% compression) l=sample length w width of fabric The figures obtained are set out in Table VIII below.

TABLE VIIL-BENDING STIFFNESS OF FABRICS lower shear moduli. The shearing properties of fabric No. 1 (100% wool), fabrics Nos. 2 and 3 (100% Acrilan) and fabrics Nos. 4 and 5 (50% Acrilan/50% wool) were The figures set out in Table VIII demonstrate that the bending stiffnesses of fabrics containing Acrilan are greatly reduced in the warp direction When the fabrics are measured on an instrument described by B. Behr in the finished by the process according to the present invention.

In the weft direction, iowever, the stiffnesses are generally increased for a reason unknown. It is evident, however, that the stiffness of fabric No. 4 (Acrilan/wool) is virtually the same as that of fabric No. 1 (100% wool) and this shows that the finish in accordance with the invention has imparted to the Acrilan/wool fabric the mechanical characteristics of an all-Wool fabric.

Tests carried out to determine whether the heat treatment in accordance with the invention impaired the fabrics demonstrated that no change occurred in the tensile strength or abrasion resistance thereof while the fastness to dry-cleaning agents or washing remained excellent.

It will be evident from the foregoing that a dry heattreatment affects the properties of fabrics such as crease recovery, recovery from buckling and resistance to shear. These properties are inherently influenced by the elasticity of the constitutent fibres in the fabric and by the frictional restraint which exists at the countless fibre-to-fibre points of contact in the fabric. The more elastic to fibre, the better will be the fabric recovery whilst large frictional restraint will tend to lower recovery. Heat treatment effectively reduces the frictional restraint, hence the fabric so treated will exhibit improved recovery characteristics.

In a woven fabric the warp and weft yarns interlace with each other and each yarn is curved or bent around numerous others. Because of their inherent elasticity the yarns tend to push against each other in an effort to regain their straightened configuration and frictional forces are developed at the contact points between the fibres. When a fabric is creased, the yarns in the fold are displaced relative to one another and attempt to return to their original positions during recovery. The elastic forces of the fibres have to overcome the frictional forces at the points of contact and therefore tend to inhibit recovery. The higher the frictional force, the poorer will be the recovery. These observations explain how constructional changes affect recovery. Varying the number of threads per inch or the yarn twist or count, will change the number of fibre-to-fibre points of contact and hence the frictional restraints.

Finishing processes which effectively reduce or even eliminate frictional restraints greatly improve the recovery of the fabrics. In wool fabrics, the forces exerted at contact points can be reduced by any of the conventional setting treatments such as decatising, blowing or pressing, because they produce a stress relaxation of the fibres in the fabric. The yarns are stabilised in the shape of their actual configuration in the fabric and therefore do not tend to exert pressure against adjacent threads. These effects are due to the chemico-physieal properties of the wool fibre and all-wool fabrics are given some, or all, of these treatments during conventional finishing. Without being so treated all-wool fabrics would be stiff and harsh with poor crease recovery properties. Polyacrylonitrile fibres, however, are not affected by the wet treatments applied to wool. Accordingly, it has been necessary to discover some other means to reduce the forces exerted between the polyacrylonitrile fibres in order to impart to a fabric containing such fibres maximum crease recovery performance. The experiments hereinbefore described demonstrate that only a high temperature treatment will afford the desired result. This is because stress decay in polyacrylonitrile fibres occurs only at high temperatures when the stresses in the fibres will decrease owing to the mobility of the chain molecules. Upon subsequent cooling the strain-free fibres assume the shape of the yarn configuration in the fabric. Heat treatment, in accordance with the invention, therefore produces the same effect upon polyacrylonitrile as decatising, blowing, or pressing produces on wool. In order to counteract any tendency for the heat-treatment step to cause spot-welding, which would set up new frictional restraints, the

10 washing-off step according to the present invention is employed.

From the foregoing it will be readily understood that the finishing process according to the invention will impart to fabrics consisting of blends of polyacrylonitrile and wool a crease-recovery performance equivalent to that of an all-wool fabric or a fabric consisting of a blend of polyester and wool. The fabrics so treated exhibit soft and supple properties and a markedly woollike handle. The process also affords improvements in recovery from buckling and in the draping characteristics of fabrics treated thereby. In addition, the fabrics so treated possess a decreased resistance to shear deformation. Thus, the fabrics are eminently adapted for use as suiting mate-rials, for which purpose fabrics consisting of blends of polyacrylonitrile and wool have hitherto not proved entirely satisfactory.

It will be understood that the foregoing details of the invention are given by way of example only and that modifications can be made to suit requirements without departing from the scope of the invention as defined by the claims.

We claim:

1. A method of finishing textile fabrics composed of blends of wool and fibers of acrylonitrile polymers, comprising the steps of subjecting the fabric to a scouring operation in a hot dilute alkaline soap solution, rinsing the scoured fabric in a hot aqueous solution, gradually cooling the fabric after rinsing, treating the cooled fabric in a hydro-extractor and drying the fabric; thereafter subjecting the fabric to hot-air treatment at a temperature in the range of 195 -200 C. for a period of up to 25 seconds to set the polyacrylonitrile component of the fabric, cooling the fabric and rinsing it in a hot solution of a softening agent, allowing the rinsed fabric to cool gradually and thereafter treating the cold fabric in a hydro-extractor and drying the fabric, blowing steam onto the dry fabric and finally applying to the fabric a dry finishing treatment.

2. A method according to claim 1, wherein scouring of the fabric is carried out in a solution consisting of 3 percent soap and 1.5 percent soda, based on the weight of the fabric, at a temperature of 45 C. for a period of up to 30 minutes, the scoured fabric being rinsed in the aqueous solution at a temperature of 45 C. for a period of up to 20 minutes and thereafter dried at a temperature of C.

3. A method according to claim 1, wherein after being treated with hot air at a temperature in the range of -200 C. and cooled, the fabric is rinsed in a /2 percent solution of a cationic softening agent, based on the weight of the fabric, at a temperature in the range of 4045 C.

4. A method according to claim 1, wherein drying of the fabric is effected at a temperature of 100 C.

5. A method according to claim 1, wherein steam is blown onto the fabric for a period of up to 2 minutes.

6. A method according to claim 1, wherein the final dry finishing treatment comprises the steps of applying steam to the fabric, brushing the steamed fabric, cropping the fabric, followed by further steaming of the fabric and pressing thereof.

7. Textile fabrics produced by the process of claim 1.

References Cited UNITED STATES PATENTS 2,669,002 2/1954 Dalton et al. 28-76 2,925,639 2/1960 La Fleur 2619 FOREIGN PATENTS 1,318,988 1/1963 France.

NORMAN G. TORCHIN, Primary Examiner.

75 J. CANNON, Examiner.

Claims (1)

1. A METHOD OF FINISHING TEXTILE FABRICS COMPOSED OF BLENDS OF WOOL AND FIBERS OF ACRYLONITRILE POLYMERS, COMPRISING THE STEPS OF SUBJECTING THE FABRIC TO A SCOURING OPERATION IN A HOT DILUTE ALKALINE SOAP SOLUTION, RINSING THE SCOURED FABRIC IN A HOT AQUEOUS SOLUTION, GRADUALLY COOLING THE FABRIC AFTER RINSING, TREATING THE COOLED FABRIC IN A HYDRO-EXTRACTOR AND DRYING THE FABRIC; THEREAFTER SUBJECTING THE FABRIC TO HOT-AIR TREATMENT AT A TEMPERATURE IN THE RANGE OF 195*-200*C. FOR A PERIOD OF UP TO 25 SECONDS TO SET THE POLYACRYLONITRILE COMPONENT OF THE FABRIC, COOLING THE FABRIC AND RINSING IT IN A HOT SOLUTION OF A SOFTENING AGENT, ALLOWING THE RINSED FABRIC TO COOL GRADUALLY AND THEREAFTER TREATING THE COLD FABRIC IN A HYDRO-EXTRACTOR AND DRYING THE FABRIC , BLOWING STEAM ONTO THE DRY FABRIC AND FINALLY APPLYING TO THE FABRIC A DRY FINISHING TREATMENT.

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