US2972795A - Process for treating textile materials - Google Patents

Description

Feb. 28, 1961 s. BACKER ETAL PROCESS FOR TREATING TEXTILE MATERIALS Filed Aug. 15, 1957 STRETCHING ZONE' INVENTORS STANLEY BACKER I T NORDHAMMER FIG. 5, PER G05 A O S C ATTORNEY reach the. rolls betweenwhich they pass. elongation of the material willv thus be reduced but the PROCESS FOR TREATING TEXTILE MATERIALS Stanley Backer, Waban, and Per G. Nordhammer, Cambridge, Mass., assignors to Crompton & Knowles Corporation, Worcester, Mass., acorporation of Massachusetts Filed Aug. 13, 1957, Ser. No. 677,872

Claims. (CI. 26-54) This invention relates to improvements in methods and means for treating textile and other sheet materials in such manner as to improve their dimensional stability, softness, hand, drapability, crimp, bulk, stretch, creping effect, etc. in a single operation.

Many textile and sheet materials do not drape satisfactorily and have a hard unfavorable surface, and shrink significantly in normal use. It is an important object of the present invention to provide a method andmeans for acting on materials during or subsequent to their formationor processing in conventional manner'to improve their qualities as above noted.

It is a further object of the invention to subject textile material, such as fibres, yarns, webs and fabrics, or other sheet material, to a treatment which will stretch them at the early stage of the process or treatment and then cause them to become crimped or otherwise modified in the latter part of the process.

In carrying the invention 'into effect we have found that esirable changes can be produced in textile materials by passing them between compressible media or belts, or the like, such as rubber, these belts being-driven by rolls or the like which cause compression of the belts' sufiicient to set up a high frictional contact with the textile material. As the latter is fed into the bight between the two compressible media the textile material is elongated beyond its elastic limit due to lengthwise extension of the media and because of their frictional contact with the textile material. As the belts or elastic media pass beyond their stage of maximum compression they begin to contract in an effort to recover their original form and in doing so produce a crimping or shortening effect on the textile material which gives the latter improved qualities. The degree to which the desired qualities are imparted to the textile materials can be varied partly by choice'of the materials themselves and partly by the pressure exerted on them by the rubber belts.

It is a further object of the invention to provide means for varying the length of the textile material after-it has been acted on according to the present invention. If. for instance it is' desired that the. material subject to treatment shall be shortened this result. can be accomplished by: a .relative increase in thecontraction of the material when the compressive force is reduced on the belts and this is attained by 'pretensioning the latter beforev they The relative contracting effect. will remain. the same so that propertionately there will be a greater shortening than the preflit d S et- S Patent 0. 5

2,972,795 Patented Feb. 28, 1961 ice vious stretching. The pretensioning can in fact be high enough so that little or no extension of the belts occurs, in which case the shortening of the material is the principal, or sole result. If, on the other hand, it is desired to lengthen the material the belts are post-tensioned after they leave the rolls so that their contraction will be reduced and the crimping or shortening of the material will be less in proportion to its previous stretching.

The post tensioning can be high enough so that little or no contraction occurs, in which case the lengthening or stretching of the material is the principal or sole result.

In order that the invention may be clearly understood reference is made to the accompanying drawing which illustrates by way of example two embodiments of the invention and in which:

Fig. l is a diagrammatic view showing the mechanism for carrying the invention into effect,

Fig. 2 is an enlarged diagrammatic view illustrating the manner in which the elastic media or belts are laterally compressed to cause longitudinal extension and then later in the process, upon reduction of compression, contract in the longitudinal direction,

Fig. 3 is a Z-part view showing a yarn before and after treatment according to the invention, without preor posttensioning,

Fig. 4 is also a 2-part view but showing, as one example, a fabric before and after being treated according to the invention,

Fig. 5 is a diagram showing the different stages of treatment of a textile material, as an example, according to the invention.

Referring to Fig. 1, upper and lower rolls 10 and 11 are driven by gearing 12 so that they rotate in opposite directions as indicated by the arrows. A 'set of three upper guide rolls indicated at 13, 14 and 15 support a belt 16 which is preferably made of soft elastic rubber, and other lower guide rolls 17, 18 and 19 similarly support an elastic belt 20. Each of the belts 16 and 20 may in fact be made of more than one ply and in one experiment which was performed each of the three plies was slightly more than A3 thick.

The textile material to be acted on according to the invention is shown at T and is fed in from the left and is discharged at T at the right. Suitable supports for the material T, T can be provided although they are not shown herein. The feeding of the textile material through the machine is accomplished by the rotation of the belts 16 and 20.

Fig. 2, which shows on an enlarged scale those parts illustrated in Fig. 1 which have a more immediate bearing on the operation of the invention, shows the belts 16 and 20 of reduced thickness at 21 caused by the fact that the distance between adjacent surfaces of the rolls 10 and 11 is noticeably less than the combined original or normal thickness of the two belts 16 and 20. The belts are therefore subjected to lateral compression between the rolls and this compression results in their longitudinal elongation while they are in frictional contact with the. textile material T. This material is therefore stretched as. it passes between the rolls and as the belts reach a point beyond or to the right of a line joining the axes ofthe rollsas viewed in Fig. 1, they begin to recover their original thickness as at and indoingsocontract longitudinally while still in frictional contact with the textile material. It is this contraction which produces the shortening or crimping of the textile material and this latter action is effected before the belts move far enough apart to lose their contact with the material.

As a result of the stretching due to the elongation of the rubber belts and then shortening or crimping due to the contraction of the belts the textile material is found to have a much improved quality, being softer and more stretchable and in the case of a fabric possessed of improved draping qualifies.

Fig. 3 shows the preferred form of the invention wherein a single yarn has been treated by the process, this yarn shown at 25 and at the left of Fig. 3 is in its original form and at the right in the form it has after being treated. We have found that a yarn so treated has been increased in length, and also has improved qualities of softness, bulk, crimp and stretchiness. In other yarns treated the length of the yarn has remained unchanged or shortened, while retaining the other qualities mentioned.

in Fig. 4 the fabric 26 at the left is an untreated, nonwoven specimen, while that at the right illustrates the character of the fabric after it has been treated according to the invention. Other fabrics, especially those including plastic fibers, which we have produced have one or more of the qualities already described for the yarn shown in Fig. 3.

If two different kinds of fibers are used in a nonwoven fabric, such as those of a nylon and a viscose variety, the stronger type 28 having the higher extensibility exnot only produces the irregular pattern effect indicated in Fig. 4, but acts also as a soft filling.

, varied depending upon the kinds of fibers or materials used. Heat also has the advantage of facilitating the Fig. 5 shows diagrammatically the successive stages '7 through which the textile material passes when being submitted to the treatment set forth herein. The material is assumed to travel in the direction of the arrow and'the part designated at O is the original untreated fiber, yarn or fabric before it reaches the rubber belts. During the first part of the contact which the material has with the belts" it is subjected to a tensioning or stretching which is represented at S in Fig. 5. As the material continues to f move along with the rubber belts it is then contracted or crimped as at C during the stage of the operation when the belts recover their original form.

While the belts have been shown astravelin-g'around i rolls 10 and 11, it is to-be understood that the invention at least somewhat beyond its elastic limit so that it cannot recover its original length when the elastic media contract. This failure to recover original length on the part of the material provides a length which results in the shortening or buckling and crimping represented at- C in Fig. 5. This condition does not necessarily exist when post-tensioning is present, as will now be described.

The invention can also be utilized to change the density of a fabric either by a'longitudinal compressing or a stretching operation. If for instance a fabric requires'to be reduced in length in order to meet specifications then the extension of the fabric during the operation should be reduced so that the proportion of the contraction will be increased. This result may be attained by pretensioning the elastic bands 16 and 20 before they reach the rolls 10 and 11. If, on the other hand, it is desired to stretch the material the bands 16 and 20 will then bev post-ten sioned after they leave the rolls 10 and 11.

4 Preor post-tensioning of the belts 16 and 20 is effected by pinch rolls 15a and 19a which are driven either faster .or slower depending upon whether post-tensioning or pretensioning is desired. When rolls 15a and 19a feed the belts faster than their peripheral rate at the nip between rolls 10 and 11, a pull results on those parts of the belts moving toward rolls 13 and 17 to cause the post tensioning already mentioned. When rolls 15a and 19a feed the belts slower than their rate at the nip a pretensioning results. These rolls 15a and 19a can be driven by any suitable drive means.

From the foregoing it will be seen that the invention sets forth an improved method and means for first stretching a textile material and then contracting it all in one operation in a sandwich calendering which includes feeding the textile material between two elastic media which are first subjected to lengthwise extension while in frictional contact with the material and are then permitted to contract while still in frictional contact with the material. The elastic media need not necessarily be in the form of the belts shown nor will it be necessary in all instances that the media travel around the rolls 10 and 11 or their equivalents. The thickness of the belts 16 and 20 and also their inherent degree of compressibility may be varied to produce end results desired in the textile material. Thus, for instance, if the belts are comparatively thick they will produce a relatively wide nipping area for the textile material having a degree of compression and the likelihood of slip between the textile material and the elastic media will be reduced. If desired, heart may be applied to the material by heaters 30. Heat has the advantages of causing the material to act more as a plastic and less elastic to facilitate crimping or shortening of the material, and the heat provided by the heaters can be stretch of the material during the first part of the process.

The relative plasticity of textile fibers is also affected by their moisture content. If desired, the textile material entering the process can be presprayed or steamed by nozzles or other conventional devices not pictured in Fig. 1'. The effect of increasing the fiber moisture content is to facilitate the stretch of the material during the first part of the process, and in the second part of the process to facilitate the compressive shortening or crimping action as well as to increase the permanence of the textile material modifications resulting from the treatment.

-Having now particularly described and ascertained the nature of the invention and in what manner the same is to be-performed, what is claimed is:

1;. The method of treating a flexible fibrous structure, consisting in the following steps: feeding each of two elastic deformable media around a center and by a reduction of their thickness causing them as they move toward a line joining the centers to be progressively deformed lengthwise in the direction in which they move and then as they move away from said line to progressively recover from their lengthwise deformation, feeding a fibrous structure between said media and causing the latter: to establish frictional contact with the fibrous structure' and stretch the material elements of the structure beyond their tensile elastic limit as the media move toward said line and then forcing the structure to effective- 1y recover its over-all length by the media as the latter recover from their deformation, the fibrous structure undergoing its stretching and recovery while in frictional contact with the media.

2. The method set forth in claim 1 including the step of moving the media toward each other so that each deforms and elongates the surface of the other in contact with the fibrous structure to stretch the latter, and thereafter moving the media away from each other to enable the surfaces contacting the fibrous structure to contract to shorten the latter.

3. The method set forth in claim 2 wherein the media are under greater longitudinal tension when they are moving toward each other than when they are moving away from each other.

4. The method set forth in claim 2 wherein the media are under less longitudinal tension when they are moving toward each other than when they are moving away from each other.

5. The method of treating textile material consisting in the following steps: feeding the material between parts of elastic compressible media under tension which are moving toward a stretching zone, compressing the media at the zone to expand the media to longitudinally establish frictional contact with the material to stretch the 5 latter.

References Cited in the file of this patent UNITED STATES PATENTS Wrigley et a1 Nov. 26, 1935 2,522,663 Chatfield Sept. 19, 1950 FOREIGN PATENTS 376,040 Great Britain July 7, 1932

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