GB2151269A

GB2151269A - Fabric material and a process for its production

Info

Publication number: GB2151269A
Application number: GB08431747A
Authority: GB
Inventors: Rosemary Vanessa Amelia Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-12-15
Filing date: 1984-12-17
Publication date: 1985-07-17
Also published as: GB8431747D0; GB8333425D0; GB2151269B; HK97888A

Abstract

A fabric, whose appearance may resemble a cord, seersucker or blister fabric, can be produced by knitting together a contractible (e.g. elastic) yarn A and non-contractible (preferably non-elastic) yarn B, in such a way that the contractible yarn periodically floats over at least one stitch and/or at least one course, preferably whilst the non-contractible yarn is knitted in and the non-contractible yarn preferably floats whilst the contractible yarn is knitted in. The fabric may also be warp-knitted. Instead of an elastic (e.g. spandex) yarn a shrinkable (e.g. acrylic) yarn may be used. <IMAGE>

Description

SPECIFICATION Fabric material and a process for its production The present invention relates to a new fabric material and a process for knitting such a material.

Knitting is a convenient and useful way of forming a fabric from a yarn. It has, however, the disadvantage that, unless complicated patterns and stitches are used (which can be difficult or prohibitively expensive to mechanise), the product is a plain and planar (i.e. two-dimensional) product. I have now discovered a method of producing a fabric which has a non-planar surface, giving a threedimensional effect and which can form an attractive pattern. The invention is based upon the combined use of an essentially non-elastic yarn with an elastic yarn or a shrinkable yarn (elastic yarns and shrinkable yarns being collectively referred to herein as "contractible").It is, of course, well known to knit together elastic and non-elastic yarns to produce fabrics having a certain degree of elasticity and "give", but the product is, in the absence of any special knitting pattern, an essentially planar fabric.

The invention is also distinguished from the known methods of producing a "mock rib" typified by the disclosures of British Patent Specifications No. 634,830, No. 1,166,273 and No. 2,029,468.

In accordance with my invention, a non-contractible yarn and a contractible yarn are knitted together, the contractible yarn periodically floating (i.e. not being knitted into the fabric) over at least one stitch and/or at least one course, and, after knitting, the contractible yarn is caused or permitted to contract.

The terms "non-contractible" and "contractible" as applied herein to a yarn refer to the state of that yarn only in the course of the knitting process.

As noted, the contractible yarn can either be elastic or it can be shrinkable. Where it is elastic, it must be held under tension during knitting in order that, after knitting, its natural elasticity will cause it to contract. Where the contractible yarn is a shrinkable yarn, it should be subjected to the necessary treatment to cause it to shrink, for example subjected to high temperatures, e.g. by immersion in very hot water, or by chemical treatment. Since the contractible yarn is not knitted into the fabric over those sections where it floats, on these sections, it contracts and bunches the fabric together; where it is knitted in, it is prevented from contracting by the non-contractible yarn.If, as is preferred, the stitches and/or courses where the contractible yarn floats alternate with those where it is knitted in a regular periodicity, a regular bunched pattern will be produced, which may resemble a cord, a seersucker fabric or a blister fabric, depending upon the relationship between the number of stitches and/or courses (or rows) knitted and the number of stitches and/or courses where the contractible yarn floats.

In a preferred embodiment of my invention, the non-contractible (preferably non-elastic) yarn is floated while the contractible (preferably elastic) yarn is knitted in. As described below in greater detail, in this embodiment of the invention it is possible to produce a fabric having an irregular puckered effect despite the fact that the pattern of knitting is quite regular. This irregular surface effect from a regular and simple knitting pattern is believed to be unique to my invention.

Where the contractible yarn is an elastic yarn, the resulting fabric will have substantial elasticity, comparable with that of the yarn itself. This contrasts with the conventional type of fabric where elastic and non-elastic yarns are knitted together, where the elasticity of the fabric is severely constrained by the presence of non-elastic yarns.

In one preferred embodiment of the invention, the non-contractible and contractible yarns are knitted together on a knit-and-miss construction in each adjacent pair of courses or in most such pairs of the knitting, so that the non-contractible yarn is knitted into the fabric for one or more stitches, preferably for from 3 to 15 and more preferably from 4 to 12 and most preferably up to 10 stitches, whilst the contractible yarn floats (i.e. is not knitted in), after which the contractible yarn is knitted for one or more stitches (preferably from 1 to 6 stitches and more preferably from 2 to 4 stitches), whilst the non-contractible yarn is either allowed to float or is knitted in together with the contractible yarn; the pattern of knitting the non-contractible yarn whilst floating the contractible yarn and then knitting the contractible yarn then repeats until the end of the courses.This pattern of knitting and floating may repeat regularly in the course or the number of stitches knitted and/or the number of stitches floating may vary, to achieve any desired pattern. Similarly, in all or some of the subsequent pairs of courses of knitting, a similar or identical pattern of knit-and-miss may be employed, or the pattern may vary from one pair of courses to the next, preferably in an ordered fashion, to achieve any desired design (e.g. a diamond-shaped design) in the fabric. If desired, the same pattern of knitand-miss may be employed in all pairs of courses of the knitted fabric, with the knitted and floating portions of yarn in each pair of adjacent rows being in register. However, by offsetting the pattern of knitted and floating portions of yarn in some or all adjacent pairs of courses, fabrics having a different bunched pattern can be produced.

Similarly by knitting one or more sections of the fabric wholly of either non-contractible yarn or of contractible yarn without knitting in a course or courses of the other yarn, different effects can be achieved.

A particularly desirable diamond-shape pattern may be achieved by offsetting, in one direction, the position in its course where the contractible yarn is knitted in by one or a few stitches progressively in each of the next of several courses, and then offsetting that position in the opposite direction for the same number of courses, and so on.

It is highly desirable that the floating sections of yarn, whether of contractible yarn or non-contractible yarn, should be on the reverse of the fabric. If the number of stitches per course in which the contractible yarn is knitted in is kept to a minimum, then the face of the fabric will consist mostiy of the non-contractible yarn and the appearance of the contractible yarn will be minimised.

Instead of the embodiment described above in which a non-contractible yarn is knitted in to the fabric whilst a contractible yarn floats and then the contractible yarn is knitted in while the non-contractible yarn floats, it is possible to knit some or all of the fabric in such a way that the non-contractible yarn is knitted in while the contractible yarn floats and then both non-contractible and contractible yarns are knitted in together. Any combination of these arrangements is possible, provided that, in accordance with the invention, there are some sections where the contractibie yarn floats.

A wide range of yarns can be employed in the invention. Indeed, virtually any yarn may be employed as the non-contractible yarn, be it synthetic or natural. The precise non-contractible yarn chosen will be chosen primarily with regard to the desired appearance and feel of the fabric and is not critical to the present invention. If an elastic yarn is fed to the knitting machine under zero tension, then it will function as a non-contractible yarn and may be used as such. This will produce a fabric of considerable elasticity. However, the non-contractible yarn is preferably a non-elastic yarn. Suitable non-elastic yarns include tricel, cotton, polyester, linen, viscose, viscose rayon, viscose acetate, dicel duracol, tricel duracol, polyamide (including nylon), wool, cashmere, alpaca, mohair, viscose/cotton, saran, glass fibres, triacetate, camel, merino or silk, e.g. sewing silk.

On the other hand, the choice of contractible yarn is of more significance to the structure of the fabric produced by the present invention. If the contractible yarn is a shrinkable yarn having a large shrinkage or a highly elastic yarn fed under sufficient tension to manifest fully its elasticity, then the face of the fabric formed by the non-elastic yarn will be bunched tightly together to form a very tight regular or irregular pattern, with a corresponding reduction in the area of fabric produced from a given length of yarn. On the other hand, if the contractible yarn is a shrinkable yarn having a relatively low shrinkage or is an elastic yarn having a relatively low elasticity or fed under relatively low tension, then the fabric will be bunched together much more loosely to form a much looser pattern.Examples of suitable elastic yarns include shirring elastic and various spandex fibres, particu larly that sold under the trade name "Lycra" (registered trade mark). A suitable shrinkable yarn is a high shrink acrylic yarn. In one embodiment of my invention, I use a covered elastic yarn, in which an elastic yarn (such as those exemplified above) is covered with a wound coat of another (normally non-elastic) yarn, such as a nylon yarn.

Where the contractible yarn is a shrinkable yarn, the amounts of shrinkable yarn and non-contractible yarn are preferably approximately equal, based on the length of the two yarns prior to shrinkage.

Where the contractible yarn is an elastic yarn, the length of elastic yarn under tension is preferably about the same as the length of non-contractible yarn, but its length in the relaxed state is necessarily less. A preferred ratio of the relaxed length of elastic yarn to length of non-contractible yarn is from 1:5 to 29:30, more preferably from 1:3 to 6:7 and most preferably about 2:8.

In the above discussion, I have talked generally in terms of the use of two different yarns - a contractible yarn and a non-contractible yarn. Of course, it is possible, and in many cases desirable, to use more than two different kinds of yarns, e.g.

two or more contractible yarns and/or two or more non-contractible yarns. Modern knitting machines are well equipped to handle a multiplicity of different yarns. For example, in one embodiment of the invention, I knit using a contractible yarn, a first non-contractible yarn and either a second non-contractible yarn or a less contractible yarn. A suitable pattern would be: (a) knit a course of the first non-contractible yarn, e.g. in the pattern of course B in Figure 1 of the accompanying drawings; (b) then knit a course of the second non-contractible (or less contractible) yarn, e.g. in the pattern of course A of Figure 1; (c) repeat (a) and (b) a desired number, e.g.

from 6 to 12, more preferably from 6 to 10, say 8 times; (d) repeat (a); (e) knit a course of the contractible yarn, preferably in the same pattern as (b) above.

In another embodiment of the invention, I introduce at least one tuck loop just before and just after knitting in the contractible (e.g. elastic) yarn.

It is possible, and may be desirable in some cases, to put in 2 or more tuck loops adjacent each other; however, these tuck loops are not essential to the present invention.

The fabric of the present invention may be knitted on a wide variety of conventional knitting machines, preferably on the type of machines referred to as "weft" or "warp" knitting machines. Examples of the "weft" type of knitting machine are the jersey knitting machines, preferably the single jersey knitting machines. In such weft knitting machines, the yarns are knitted together as a "weft" in the fabric, without any true warp - this corresponds essentially to the conventional method of knitting by hand. A wide variety of single jersey knitting machines is available and any such machine may be used in the present invention.

An example of a "warp" type of knitting machine is the "Raschel" machine, in which one yarn, preferably the non-contractible yarn, is knitted in for all or most of the fabric, whilst the other yarn, preferably the contractible yarn, is mainly laid in. The contractible yarn would be knitted in at intervals but mainly laid in; this would give a fabric having contractibility, e.g. elasticity, in the warp direction.

In the above discussions of the structure of the fabric of the invention, the fabric has been described principally as it would be prepared by means of a weft type of knitting machine; however, the same data apply mutatis mutandis to a fabric produced on a warp type of machine.

The invention is further illustrated by the accompanying drawings, in which: Figure 7 illustrates diagrammatically three rows of knitting produced in accordance with the invention on a weft, e.g. single jersey, machine; Figure 2 illustrates one possible arrangement of warp yarn in a warp knitting process; Figure 3 illustrates an alternative arrangement of warp yarn in a warp knitting process; and Figure 4 is a drawing of the surface appearance of a fabric produced by one embodiment of the invention.

In the drawings, A represents one of the types of yarn, preferably the contractible or elastic yarn, whilst B represents the other type of yarn, preferably the non-contractible or non-elastic yarn. The loops, e.g. 1 indicate those sections where the yarn is knitted in, whilst the straight sections 2 illustrate where the yarn floats. In Figures 2 and 3, for clarity, the contractible yarn has been omitted.

Figure 4 shows the surface appearance of a fabric knitted on a weft knitting machine in accordance with the present invention. The surface is made up of irregular arrays of wavy puckers. This is achieved by using a highly elastic yarn fed under high tension (or a highly contractible yarn). The fabric also comprises a relatively high proportion of elastic (or contractible) yarn - in this case, approximately 1 course in every 2 is of this elastic (or contractible) yarn. However, for a somewhat less puckered effect a lower proportion, say 1 in 3 or 1 in 4 or anything inbetween, could be used. Equally, a more puckered effect could be achieved by using a higher proportion of elastic (or contractible) yarn, say 2 in 3 or 3 in 4, or anything inbetween.Also contributing to the loose folds in the fabric (which impart the puckered effect) of the embodiment illustrated in the drawing is a relatively long stitch length of the non-elastic (or non-contractible) yarn.

The high elasticity of fabrics achievable by the process of the invention (including that embodiment illustrated in Figure 4) leads to some exciting possibilities. For example, garments, e.g. ladies' swimsuits, can be prepared by knitting a tube of fabric on a knitting machine and the forming the garment by a few simple cutting and sewing operations. In the case of a ladies' swimsuit, this may be done by cutting scallops for shoulder and leg holes and then sewing together the appropriate parts of the fabric to form straps and a crotch portion. The elasticity of the fabric ensures that the garment is form-fitting and that the garment will fit almost all sizes from very small to very large. This "one size fits all" ability enables many different garments and styles to be produced easily and economically and avoids problems for manufacturers and retail stores of producing and stocking a large number of different sizes.

Claims

1. A process for producing a fabric, in which a non-contractible yarn and a contractible yarn are knitted together, the contractible yarn periodically floating over at least one stitch and/or at least one course, and, after knitting, the contractible yarn is caused or permitted to contract.

2. A process according to Claim 1, in which said non-contractible yarn is a non-elastic yarn.

3. A process according to Claim 1 or Claim 2, in which said contractible yarn is an elastic yarn supplied under tension to be knitted.

4. A process according to Claim 3, in which the contractible yarn is a spandex yarn.

5. A process according to Claim 1 or Claim 2, in which said contractible yarn is a shrinkable yarn and, after knitting, is subjected to treatment to cause it to shrink.

6. A process according to any one of the preceding Claims, effected on a weft knitting machine.

7. A process according to Claim 6, in which said weft knitting machine is a single jersey machine.

8. A process according to Claim 6 or Claim 7, in which, in a section of an adjacent pair of courses of knitting containing a portion where said noncontractible yarn is knitted whilst said contractible yarn floats and a portion where said non-contractible yarn floats whilst said contractible yarn is knitted in, the number of stitches where the noncontractible yarn is knitted is from 3 to 15 and the number of stitches where the contractible yarn is knitted is from 1 to 6.

9. A process according to Claim 8, in which the number of stitches where the non-contractible yarn is knitted is from 4 to 12.

10. A process according to Claim 8 or Claim 9, in which the number of stitches where the contractible yarn is knitted is from 2 to 4.

11. A process according to any one oof Claims 1 to 5, in which the knitting is effected on a warp knitting machine.

12. A process according to any one of the preceding claims, in which said non-contractible yarn is floated over those portions where the contractible yarn is knitted in.

13. A process for producing a fabric by knitting on a warp knitting machine, in which a non-contractible yarn and a contractible yarn are knitted together, the contractible yarn being knitted in at intervals and laid in inbetween, and, after knitting, the contractible yarn is caused or permitted to contract.

14. A process according to Claim 13, in which said non-contractible yarn is a non-elastic yarn and said contractible yarn is an elastic yarn knitted under tension.

15. A process according to Claim 13 or Claim 14, in which said non-contractible yarn is laid in over those portions where said contractible yarn is knitted in.

16. A process as claimed in Claim 1, substantially as hereinbefore described with reference to any one of the accompanying drawings.

17. A fabric produced by a process according to any one of the preceding claims.