GB2486273A

GB2486273A - Improvements in or relating to a combination yarn

Info

Publication number: GB2486273A
Application number: GB1020992.2A
Authority: GB
Inventors: Laurie Fluck
Original assignee: WYKES INTERNAT Ltd
Current assignee: WYKES INTERNAT Ltd
Priority date: 2010-12-10
Filing date: 2010-12-10
Publication date: 2012-06-13
Anticipated expiration: 2030-12-10
Also published as: WO2012076862A1; GB201020992D0; GB2486273B

Abstract

A combination yarn 10 comprises an elastomeric core yarn 12, such as elastane or spandex, which has a hard covering yarn 14 wrapped around it in a spiral configuration. The covering yarn 14 defines a plurality of loops 22 which extend laterally from the core 12. The covering yarn 12 includes at least one synthetic polymer filament 18, such as polyamide, polyester or polypropylene , which has a plurality of amorphous and crystalline regions of polymer chains. The polymer chains (26, figure 3) in the amorphous regions (24) and at least a portion of each crystalline region (28) have a relaxed configuration with low tension between adjacent polymer chains (26). This is achieved by heating the synthetic polymer filament to a transition temperature, which may be at least as high as the glass transition temperature, to overcome the binding forces between adjacent polymer chains. The transition temperature is preferably higher than a subsequent dying temperature such that the significant shrinkage does not occur during dying. Other fibres such as cotton may be wrapped around the combination yarn to form a composite yarn. The yarn may be used for knitting.

Description

IMPROVEMENTS IN OR RELATING TO

A COMBINATION YARN

This invention relates to a combination yarn, a composite yarn including the aforementioned combination yarn, a textile fabric including a combination yarn and/or a composite yarn, and a method of manufacturing a combination yarn.

Many garments are knitted using natural fibres such as cotton, or natural fibre blends including cotton. Various synthetic fibres may also be used to knit garments One drawback of many of the aforementioned fibres is that they exhibit no elasticity and so the resulting garment has difficulty recovering its original shape when worn. As a result such garments tend to adopt a misshapen and baggy appearance which is undesirable.

In order to overcome the aforementioned difficulty such inelastic fibres are often used in combination with a support yarn that includes an elastomeric yarn to provide the desired elasticity and resulting garment recovery.

The elastomeric yarn is relatively soft and so is often combined with a harder yarn that is formed from one or more synthetic polymer filaments. The hard yarn covers the elastomeric yarn and serves to protect it from abrasion during the subsequent knitting process. The hard yarn also helps to control the amount of draft, i.e. stretching, of the elastomeric yarn that occurs during subsequent processing.

Although use of a combination yarn as mentioned above provides the resulting knitted garment with a desired degree of recoverability, it limits the manner in which a coloured knitted garment can be produced.

In particular, a conventional combination yarn cannot be dyed because it shrinks excessively when exposed to the heat generated during a normal dying process.

As a result it is necessary either to incorporate pre-coloured synthetic polymer filaments in the combination yarn to match the desired colour of the knitted garment, or to utilise a very fine combination yarn which is essentially invisible to the naked eye.

I

Such limitations require garment knitters to hold stock of various different coloured combination yarns which increases their costs, as well as limiting their ability to respond quickly to demand for garments of other colours.

Meanwhile a very fine, virtually invisible combination yarn is normally plated within the knitted garment. Such plating slows knitting speeds and limits the type of knitting machinery that can be used to manufacture a garment. In addition it is not possible to knit certain patterned fabric types such as, for example, intarsia and jacquard with such a very fine combination yarn.

There is, therefore, a need for an improved combination yarn which provides greater flexibility in the knitting of coloured garments.

According to a first aspect of the invention there is provided a combination yarn comprising an elastomeric core yarn having a hard covering yarn wrapped therearound in a spiral configuration, the covering yarn defining a plurality of loops extending laterally from the core yarn, and the covering yarn including at least one synthetic polymer filament having a plurality of amorphous and crystalline regions of polymer chains, the polymer chains in the amorphous regions and at least a portion of each crystalline region having a relaxed configuration with low tension between adjacent polymer chains.

The provision of such relaxed polymer chains means that when the combination yarn is exposed to an elevated temperature, e.g. during an in-yarn-, fabric-, or garment-dying process, and the binding forces between adjacent polymer chains are overcome, the polymer chains have a limited tendency to contract further and so the corresponding yarn maintains its pre heat exposure length, i.e. its pre-dying length. As a consequence any shrinking of a fabric or garment incorporating the combination yarn of the invention is limited primarily to that caused by normal relaxing of the knitted loop structure. Such normal shrinking is typically not more than about 10% of the original fabric/garment size, and so the dyed fabric/garment remains suitable for subsequent sale and/or further use.

The combination yarn of the invention allows, therefore, dying of a fabric or garment in which it is knitted, and so greatly increases the flexibility with which coloured knitted garments can be made.

Optionally the elastomeric yarn is or includes elastane.

Elastane has desirable elastic properties while permitting subsequent knitting of the resulting combination yarn.

Preferably the covering yarn includes at least one of the following: a polyamide filament; a polyester filament; and a polypropylene filament.

Each of the foregoing filaments has desirable structural characteristics to support the core yarn while permitting conditioning to include amorphous and crystalline regions having polymer chains in the desired relaxed configuration.

In a preferred embodiment of the invention the polymer chains in the whole of each crystalline region have a relaxed configuration.

Such an arrangement helps to ensure that there is no residual tension between adjacent polymer chains in the or each polymer filament, and thereby minimises any contraction of the combination yarn on exposure to an elevated temperature.

According to a second aspect of the invention there is provided a composite yarn comprising a combination yarn according to any preceding claim together with at least one other fibre.

The composite yarn shares the advantages mentioned above in connection with the combination yarn while permitting the ready introduction of the combination yarn directly into a knitting process.

The combination yarn may define a combination core about which the or each other fibre is wrapped.

Such an arrangement allows the combination yarn to provide a desired degree of structural integrity to a knitted garment while the or each other fibre, which may be subsequently dyed, obscures the combination yarn.

Optionally first and second other fibres are wrapped around the combination core. The wrapping of first and second other fibres around the combination core provides for a balanced composite yarn with a low tendency to twist in one direction or another.

In another preferred embodiment of the invention the first and second other fibres are or include cotton fibres.

Cotton fibres have desirable drape and handle characteristics and readily accept a coloured dye.

The first and second other fibres may be single twisted components. Such components are relatively inexpensive and so the resulting composite yarn is also relatively inexpensive while having the desirable characteristics mentioned above.

According to a third aspect of the invention there is provided a textile fabric comprising a combination yarn as described hereinabove and/or a composite yarn as described hereinabove.

Such a textile fabric shares the advantages mentioned above in relation to the combination yarn of the invention.

According to a fourth aspect of the invention there is provided a method of manufacturing a combination yarn comprising the steps of: (a) providing an elastomeric core yarn; (b) wrapping a hard covering yarn around the core yarn in a spiral configuration defining a plurality of loops extending laterally from the core yarn; (c) providing the covering yarn wi.th at least one synthetic polymer filament having a plurality of amorphous and crystalline regions of polymer chains; (d) heating the or each synthetic polymer filament to a transition temperature to overcome the binding forces between adjacent polymer chains in the amorphous regions and at least a portion of each crystalline region and to allow the said polymer chains to adopt a relaxed configuration with low tension between adjacent polymer chains; and (e) cooling the or each synthetic polymer filament to allow the reforming of binding forces between the relaxed polymer chains.

Allowing the said polymer chains to adopt a relaxed configuration means that when the combination yarn is subsequently exposed to an elevated temperature, e.g. during a dying process, and the binding forces between adjacent polymer chains are overcome, the polymer chains have a limited tendency to contract further and so the corresponding yarn maintains its pre heat exposure length, i.e. its pre dying length.

Such a combination yarn can, therefore, be dyed in a fabric or garment without causing excessive shrinking of the fabric or garment in which it is knitted, and so the flexibility with which coloured knitted fabrics or garments can be made is much improved.

In a further preferred embodiment of the invention the transition temperature is higher than a predetermined dye temperature which the combination yarn might be subjected to in a subsequent dying process.

Such a step helps to ensure that all of the binding forces between adjacent polymer chains that would be overcome by heating the combination yarn up to the dye temperature, would already have been overcome on heating to the transition temperature, and so all of the polymer chains released during dying would already be in a relaxed configuration and would therefore have little tendency to contract.

Optionally the transition temperature is at least equal to the glass transition temperature of the corresponding synthetic polymer filament. Such a transition temperature helps to ensure that the binding forces between adjacent polymer chains in the amorphous regions are all overcome and so the said polymer chains are all able to adopt a relaxed configuration.

Another preferred embodiment of the invention includes heating the or each synthetic polymer filament to a temperature of between 70°C and 200°C.

Heating the or each synthetic polymer filament within the specified range helps to ensure a desired extent of the polymer chains are able to adopt a relaxed configuration while maintaining the overall structural integrity of the combination yarn.

The method of manufacturing a combination yarn may include the further step of: (f) combining the combination yarn with at least one other fibre to define a composite yarn.

Combining the combination yarn with at least one other fibre permits the ready introduction of the combination yarn directly into a knitting process Preferably combining the combination yarn with at least one other fibre includes wrapping the or each other fibre about a combination yarn core.

Such a step allows the or each other fibre to obscure the combination yarn, and so thereby help ensure accurate colour matching of the composite yarn within a knitted garment.

Another preferred embodiment of the invention includes wrapping first and second other fibres about the combination yarn core.

The wrapping of first and second other fibres about the combination yarn core helps to reduce the tendency of the composite yarn to twist in one direction or another.

The method of manufacturing a combination yarn may include wrapping first and second Is cotton fibres about the combination yarn core.

Cotton fibres have desirable drape and handle characteristics, as well as readily accepting a dye.

There now follows a brief description of preferred embodiments of the invention, by way of non-limiting example, with reference being made to the accompanying drawings in which: Figure 1 shows a combination yarn according to a first embodiment of the invention including an enlarged view of a section of the yarn; Figure 2 shows a cross-section view at VI-VI of Figure 1; Figure 3 shows an enlarged schematic view of a section of synthetic polymer filament forming part of the combination yarn shown in Figure 1; and Figure 4 shows a partially wound composite yarn according to a second embodiment of the invention.

A combination yarn according to a first embodiment of the invention is designated generally by the reference numeral 10.

The combination yarn 10 includes an elastomeric core yarn 12 around which is wrapped a hard covering yarn 14.

In the embodiment shown the core yarn 12 is an elastane (which in some territories is known as spandex) yarn 16, and the covering yarn 14 includes a single synthetic polymer filament 18. The single synthetic polymer filament 18 is a polyamide filament, and in particular a nylon filament 20.

Other embodiments of the invention (not shown) may include a different core yarn 12, and/or a different covering yarn 14 which may include a plurality of synthetic polymer filaments selected from, for example, polyamide, polyester and polypropylene filaments.

The nylon filament 20 is wrapped around the elastane yarn 16 in a spiral configuration and defines a plurality of loops 22 which extend laterally from the elastane yarn 16.

The nylon filament 20 includes a plurality of amorphous regions 24 of polymer chains 26, and a plurality of crystalline regions 28 of polymer chains 26, as shown schematically in Figure 3.

The polymer chains 26 in each of the aforementioned regions 24, 28 are held together by discrete bonding forces 30.

The polymer chains 26 in the amorphous regions 24 and in a portion of each of the crystalline regions 28 have a relaxed configuration with low tension between adjacent polymer chains 26.

A relaxed configuration in the context of this application means a configuration in which a given polymer chain 26 is not extended, i.e. not held in tension.

In other embodiments of the invention (not shown) the polymer chains 26 in the whole of each crystalline region 28 have a relaxed configuration.

In use the combination yarn 10 can be exposed to an elevated temperature, e.g. during a dying process, without suffering from any catastrophic shrinking.

This is because as the binding forces between adjacent polymer chains are overcome, the polymer chains are already in a relaxed configuration and so have a limited tendency to contract further. As a result the corresponding combination yarn 10 maintains its pre heat exposure length.

Such a combination yarn 10 can, therefore, be dyed when incorporated in a fabric or garment without causing excessive shrinkage of the fabric or garment.

In particular, any shrinkage of a fabric or garment in which the combination yarn is knitted is primarily limited to normal contraction arising from relaxation of the knitted loop structure when exposed to an elevated temperature. Such normal shrinkage is typically in the region of 20% to 40% of the original size of the article by area, and so the resulting dyed fabric/garment remains perfectly acceptable for subsequent sale and/or processing.

As a result the flexibility with which coloured knitted garments can be made is greatly increased.

A composite yarn according to a second embodiment of the invention is designated generally by the reference numeral 50.

The composite yarn 50 includes a combination yarn 10, as described above, together with first and second other fibres 52, 54.

In particular, the first and second other fibres 52, 54 are wrapped around the combination yarn 10 which in turn defines a combination core 56.

In the embodiment shown each of the first and second other fibres 52, 54, is a single twisted component formed from cotton.

Other embodiments of the invention (not shown) may include a different other fibre and/or different other fibre combinations.

The combination yarn 10 in the embodiments mentioned above is manufactured by: (a) providing the elastane core yarn 16; (b) wrapping the nylon filament 20 around the elastane yarn 16 in a spiral configuration to define a plurality of loops 22 which extend laterally from the elastane yarn 16; (c) heating the nylon filament 20 to a transition temperature between 140°C and 200°C to overcome the binding forces between adjacent polymer chains 26 in the amorphous regions 24 and a portion of each crystalline region 28 and to allow the said polymer chains 26 to adopt the relaxed configuration with low tension between adjacent polymer chains 26; and (d) cooling the nylon filament 20 to allow the reforming of binding forces between the relaxed polymer chains 26.

The manufacturing steps mentioned above, and the heating step in particular, take place with the combination yarn 10 in a dry condition.

In a further preferred embodiment of the invention the synthetic polymer filament, e.g. the nylon filament 20, is heated to a temperature of 180° to 190°C.

In other embodiments of the invention the heating step may take place while the combination yarn 10 is in a wet condition, and in such cases the nylon filament (or other corresponding synthetic polymer filament) may be heated to a transition temperature lying in the range 70° to 120°C.

Claims

CLAIMS: 1. A combination yarn comprising an elastomeric core yarn having a hard covering yarn wrapped therearound in a spiral configuration, the covering yarn defining a plurality of loops extending laterally from the core yarn, and the covering yarn including at least one synthetic polymer filament having a plurality of amorphous and crystalline regions of polymer chains, the polymer chains in the amorphous regions and at least a portion of each crystalline region having a relaxed configuration with low tension between adjacent polymer chains.
2. A combination yarn according to Claim I wherein the elastomeric yarn is or includes elastane.
3. A combination yarn according to Claim I or Claim 2 wherein the covering yarn includes at least one of the following: a polyamide filament; a polyester filament; and a polypropylene filament.
4. A combination yarn according to any preceding claim wherein the polymer chains in the whole of each crystalline region have a relaxed configuration.
5. A composite yarn comprising a combination yarn according to any preceding claim together with at least one other fibre.
6. A composite yarn according to Claim 5 wherein the combination yarn defines a combination core about which the or each other fibre is wrapped.
7. A composite yarn according to Claim 6 wherein first and second other fibres are wrapped around the combination core.
8. A composite yarn according to Claim 7 wherein the first and second other fibres are or include cotton fibres.
9. A composite yarn according to Claim 7 or Claim 8 wherein the first and second other fibres are single twisted components.
10. A textile fabric comprising a combination yarn according to any of Claims I to 4 and/or a composite yarn according to any of Claims 5 to 9.
11. A method of manufacturing a combination yarn comprising the steps of: (a) providing an elastomeric core yarn; (b) wrapping a hard covering yarn around the core yarn in a spiral configuration defining a plurality of loops extending laterally from the core yarn; (c) providing the covering yarn with at least one synthetic polymer filament having a plurality of amorphous and crystalline regions of polymer chains; (d) heating the or each synthetic polymer filament to a transition temperature to overcome the binding forces between adjacent polymer chains in the amorphous regions and at least a portion of each crystalline region and to allow the said polymer chains to adopt a relaxed configuration with low tension between adjacent polymer chains; and (e) cooling the or each synthetic polymer filament to allow the reforming of binding forces between the relaxed polymer chains.
12. A method of manufacturing a combination yarn according to Claim 11 wherein the transition temperature is higher than a predetermined dye temperature which the combination yarn might be subjected to in a subsequent dying process.
13. A method of manufacturing a combination yarn according to Claim 11 or Claim 12 wherein the transition temperature is at least equal to the glass transition temperature of the corresponding synthetic polymer filament.
14. A method of manufacturing a combination yarn according to any of Claims 11 to 13 including heating the or each synthetic polymer filament to a temperature of between 70°C and 200°C.
15. A method of manufacturing a combination yarn according to any of Claims 11 to 14 including the further step of: (f) combining the combination yarn with at least one other fibre to define a composite yarn.
16. A method of manufacturing a combination yarn according to Claim 15 wherein combining the combination yarn with at least one other fibre includes wrapping the or each other fibre about a combination yarn core.
17. A method of manufacturing a combination yarn according to Claim 16 including wrapping first and second other fibres about the combination yarn core.
18. A method of manufacturing a combination yarn according to Claim 17 including wrapping first and second cotton fibres about the combination yarn core.
19. A combination yarn generally as described herein with reference to and/or as illustrated in the accompanying drawings.
20. A composite yarn generally as described herein with reference to and/or as illustrated in the accompanying drawings.
21. A textile fabric generally as described herein with reference to and/or as illustrated in the accompanying drawings.
22. A method of manufacturing a combination yarn generally as described herein with reference to and/or as illustrated in the accompanying drawings. S 13AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS1. A combination yarn comprising an elastomeric core yarn having a hard covering yarn wrapped therearound in a spiral configuration, the covering yarn defining a plurality of loops extending laterally from the core yarn, and the covering yarn including one or more synthetic homopolymer filaments each having a plurality of amorphous and crystalline regions of polymer chains, the polymer chains in the amorphous regions and at least a portion of each crystalline region having a relaxed configuration with low tension between adjacent polymer chains.2. A combination yarn according to Claim 1 wherein the elastomeric yarn is or includes elastane.3. A combination yarn according to Claim I or Claim 2 wherein the covering yarn is includes at least one of the following: a polyamide filament; a polyester filament; and a polypropylene filament. * a, * a a ** a4. A combination yarn according to any preceding claim wherein the polymer chains in the whole of each crystalline region have a relaxed configuration.5. A composite yarn comprising a combination yarn according to any preceding claim together with at least one other fibre.6. A composite yarn according to Claim 5 wherein the combination yarn defines a combination core about which the or each other fibre is wrapped.7. A composite yarn according to Claim 6 wherein first and second other fibres are wrapped around the combination core.8. A composite yarn according to Claim 7 wherein the first and second other fibres are or include cotton fibres.9. A composite yarn according to Claim 7 or Claim 8 wherein the first and second other fibres are single twisted components.10. A textile fabric comprising a combination yarn according to any of Claims 1 to 4 and/or a composite yarn according to any of Claims 5 to 9.11. A method of manufacturing a combination yarn comprising the steps of: (a) providing an elastomeric core yarn; (b) wrapping a hard covering yarn around the core yarn in a spiral configuration defining a plurality of loops extending laterally from the core yarn; (c) providing the covering yarn with one or more synthetic homopolymer filaments each having a plurality of amorphous and crystalline regions of polymer chains; (d) heating the or each synthetic homopotymer filament to a transition temperature to overcome the binding forces between adjacent polymer chains in the amorphous regions and at least a portion of each crystalline region and to allow the said polymer chains to adopt a relaxed configuration with low tension between adjacent polymer chains; and is (e) cooling the or each synthetic homopolymer filament to allow the *. reforming of binding forces between the relaxed polymer chains. * .ê * * 412. A method of manufacturing a combination yarn according to Claim 11 wherein the transition temperature is higher than a predetermined dye temperature which the combination yarn might be subjected to in a subsequent dying process. .413. A method of manufacturing a combination yarn according to Claim 11 or Claim 12 wherein the transition temperature is at least equal to the glass transition temperature of the corresponding synthetic homopolymer filament.14. A method of manufacturing a combination yarn according to any of Claims 11 to 13 including heating the or each synthetic homopotymer filament to a temperature of between 70°C and 200°C.15. A method of manufacturing a combination yarn according to any of Claims 11 to 14 including the further step of: (f) combining the combination yarn with at least one other fibre to define a composite yarn.18, A method of manufacturing a combination yarn according to Claim 15 wherein combining the combination yarn with at least one other fibre includes wrapping the or each other fibre about a combination yarn core.17. A method of manufacturing a combination yarn according to Claim 16 including wrapping first and second other fibres about the combination yarn core.18. A method of manufacturing a combination yarn according to Claim 17 including wrapping first and second cotton fibres about the combination yarn core.19. A combination yarn generally as described herein with reference to and/or as illustrated in the accompanying drawings.20. A composite yarn generally as described herein with reference to and/or as illustrated in the accompanying drawings.21. A textile fabric generally as described herein with reference to and/or as illustrated in the accompanying drawings.22. A method of manufacturing a combination yarn generally as described herein with reference to and/or as illustrated in the accompanying drawings.