COMPOSITE YARNS AND METHOD OF MANUFACTURE

Abstract: Composite stipple yarn and method of manufacture in which the yarn has two types of thread (2, 4), one thread (4) having a lower count than the other thread or threads (2). One type of thread (4) has a different affinity to a predetermined dye to that of the other thread or threads (2). The composite yarn is overdyed in the predetermined dye. This dyes only those threads (4) of one type which are susceptible to the dye, but does not change the colour of the other type of thread (2). This improves stock control and the speed at which a desired stipple yarn can be supplied.

Description: COMPOSITE YARNS AND METHOD OF MANUFACTURE Background to the invention. The present invention relates to composite yarns which are especially suited for use in carpet manufacture, and a method of making such yarns . Composite stipple yarns usually comprise two, three or four threads of the same count, at least one of which has a different colour to the other threads. Such a yarn is typically formed by individually forming and colouring the individual threads, and subsequently combining these, for example by twisting, to form the final yarn. The individual threads may either be coloured by dyeing before they are spun, or may be formed into threads first and then dyed. Typically, it takes some time to prepare an individual thread of a particular desired colour. Accordingly, to produce a stipple yarn of a particular desired combination of colours where each of the colours must individually be produced will take in the order of three to five weeks. This lead time is unacceptably long, especially in the contract market where a relatively small amount of a particular stipple yarn may be required at short notice. Due to the plurality of different colour threads used in a composite stipple yarn, there is a vast number of different possible composite stipple yarns due to the almost infinite number of different possible combinations of colours of thread. It is therefore not practical or economic to produce and store composite stipple yarns of all possible colour combinations so that these can be supplied to a customer on demand. A further problem with the manufacture of conventional composite stipple yarns is that of wastage. When colouring a thread, it is not possible to accurately manufacture threads to predetermined exact length. Therefore, when a number of threads are combined to form the composite stipple yarn, there will always be an excess of some of the threads, and this must be wasted. It has recently been proposed that a composite stipple yarn may include one thread which has a lower count, namely the weight per unit length of the yarn, than the other threads. Typically, this thin thread or "fine point leg" comprises between 10 and 25% of the resultant yarn count. Such fine point stipple yarns have a distinctive and attractive appearance which is particularly useful where the yarn is used in the manufacture of carpets. Summary of the present invention. According to a first aspect of the present invention, a composite yarn comprises a plurality of threads, one of which has a lower count than the other thread or threads, the overall composition of the yarn including at least 40% wool by weight, the thread with the lower count having an affinity to a predetermined dye different to that of the other thread or threads . According to a second aspect of the present invention, a method of making a composite stipple yarn comprises the step of forming a composite yarn in accordance with the first aspect of the present invention, and subsequently dyeing the composite yarn in the predetermined dye so that the thread with the lower count has a different colour or shade to the other thread or threads . In accordance with the present invention, it is possible to produce and stock a limited number of composite yarns each of which comprise a plurality of threads, one or more of which have their final colour, and the other or others of which can be dyed subsequently when required to a desired colour. Accordingly it is not necessary to stock different composite yarns for every possible combination of colours required, but it is necessary to stock only a limited number of composite yarns corresponding to the different colours of the threads which are not dyed subsequently. This improves the stock control, and reduces the lead time for a particular composite yarn as it is necessary only to take one of the limited number of stock yarns and subject this to a single overdyeing process. Stock control may be improved further by storing the individual threads which form the composite yarn separately. When a desired composite stipple yarn is required, it is necessary only to select the required non- overdyeable thread or threads and the standard dyeable thread or threads and twist these before overdyeing the composite yarn. Furthermore, there is less wastage than with the prior art systems since it is not necessary to individually dye each of the threads which form each possible combination of final yarns, and therefore there is less excess thread dyed to a particular colour. The thread with the lower count may have a different composition from the or each other thread, and thereby have a different affinity to the predetermined dye. In any case, it is preferred that either the thread with the lower count or the or each other thread is treated to change its affinity to the predetermined dye. This treatment may be a chemical treatment such as the "SANDOSPACE R" treatment or other treatment by which a generally colourless reactive dye is applied to the thread to fill the dye sites and prevent subsequent dyeing. Preferably the thread with the lower count comprises between 10% and 35% of the composite yarn count, and more preferably between 10% and 25% of the overall count of the composite yarn. It is preferred that the composite yarn is a wool rich yarn having at least 50% wool by weight. It is more preferred that the composite yarn has at least 70% wool, and even more preferred that the composite yarn has at least 80% wool. Preferably each of the individual threads has at least 40% wool by weight. The thread having the lowest count preferably has between 40% and 60% wool, and the remainder polyester. This gives some inherent resistance to the predetermined dye. The other thread or threads preferably have between 80% and 90% wool, and the remainder polyamide . It is preferred that the resultant count of the composite yarn is between about 2000 and 200 tex, and more preferably between about 1000 and 350 tex. Preferably, each thread used to form the composite yarn comprises a staple fibre. It is preferred that the thread having the lower count has a greater resistance to the predetermined dye than the other thread or threads. The thread having the lowest count may have a darker colour than that of the other thread or threads after these have been dyed. This is advantageous as, despite the general resistance to the dye of the thread having the lower count, the thread may be discoloured slightly by the dye. Where the dye has a lighter colour than that of the fine point leg, there will be little if any appreciable change in the overall colour of the thinner thread. Advantageously, the thread having the lowest count or the other thread or threads are pretreated before they are formed into the composite yarn, for example by space dyeing in which the thread is differentially coloured along its length, or by heathering whereby the thread is textured. These give additional appealing appearance or wear characteristics. Although the overdyeing of the composite yarn will set the twist in the yarn, it is advantageous to set the yarn before it is overdyed. This allows a greater amount of setting, and allows the composite yarn to merely be overdyed before it is used. The composite yarn may be overdyed before it is used, or may be formed into an article, such as a carpet, and then printed, for example by ink jet or screen printing. According to a third aspect of the present invention, a carpet is formed from composite stipple yarns according to the first aspect of the present invention manufactured in accordance with the second aspect of the present invention. Although it has been known to manufacture carpet using composite stipple yarn, the long lead time required to make such yarn by known methods makes the wide scale use of such yarn, especially for small lengths of carpet, impractical. The present invention overcomes these problems. Brief description of the drawings. Figure 1 is a schematic side view of a composite stipple yarn made in accordance with the present invention; and, Figure 2 is a schematic plan view of part of a cut pile carpet formed using the composite yarn of Figure 1. Detailed description of a preferred example. As shown in Figure 1, the composite yarn is formed from a first thread (4) having a composition of 50% wool and 50% polyester, and at least two other threads (2) each having a composition of 87% wool and 13% polyamide . The thread (4) having the 50% wool and 50% polyester composition has a thinner count than each of the other threads (2) . This thread (4) is coloured, for example using dye to its final desired colour, and is then subjected to a chemical treatment using the "SANDOSPACE R" process to make this thread substantially resistant to a predetermined type of dye. The other threads retain their natural colour. The three threads are twisted or wound together to form a composite yarn in which the thinner thread (4) contributes between 10% and 25% of the overall counts of the yarn. As shown in Figure 1, the thinner, darker thread (4) is twisted with the thicker threads (2) . The composition and chemical treatment of the thinner thread (4) is such that this thread is substantially resistant to a dye such as acid levelling, half milling, milling, super milling, milling fast, premetallised, reactive or mordane dyestuffs, whereas the other threads (2) have an affinity to this dye. The composite yarn is dyed in this dye. Due to the resistance of the thinner thread (4) to the dye, the dying causes no change in the colour of the thinner thread (4) . The remaining threads (2) are dyed to a desired colour. The final colour of the dyeable threads (2) is lighter than that of the thinner thread (4) so that the colour of the think thread (4) is not altered substantially even if this thread has some affinity to the dye. The composite stipple yarn may be used in the manufacture of carpets, and in this case the yarn forms the carpet tufts. Where the carpet includes looped tufts, the edge of the yarn as shown in Figure 1 will be seen when looking at the carpet. Alternatively, where the tufts are cut, the cross-section of the yarn will be visible. As shown in Figure 2, the overall appearance of the carpet will be of the colour of the thicker threads (4) as these contribute the largest proportion of the exposed yarn. However the fine point leg (2) will break up this colour giving the desired stipple effect. This means that it is possible to stock yarns having the fine point leg (2) dyed to one of a limited number of predetermined colours, and overdye these yarns to colour the thicker threads (4) to the customer required colour.

Claims: CLAIMS 1. A composite yarn comprising a plurality of threads (2,4), one of which (2) has a lower count than the other thread or threads (4) , the overall composition of the yarn including at least 40% wool by weight, the thread (2) with the lower count having an affinity to a predetermined dye different to that of the other thread or threads (4) . 2. A composite yarn according to claim 1, in which the thread (4) with the lower count has a different composition from the or each other thread (2) . 3. A composite yarn according to claim 1 or 2 , in which the thread (4) with the lower count comprises between 10% and 35% of the composite yarn count. 4. A composite yarn according to claim 3 , in which the thread (4) with the lower count comprises between 10% and 25% of the overall count of the composite yarn. 5. A composite yarn according to any one of the preceding claims, in which the composite yarn is a wool rich yarn having at least 50% wool. 6. A composite yarn according to claim 5, in which the composite yarn has at least 70% wool, and preferably at least 80% wool. 7. A composite yarn according to any one of the preceding claims, in which the thread (2) having the lowest count has between 40% and 60% wool, and the remainder polyester. 8. A composite yarn according to any one of the preceding claims in which each of the threads includes at least 40% wool by weight . 9. A composite yarn according to any one of the preceding claims, in which the composite yarn has a resultant count of between about 2000 and 200 tex, and preferably between about 1000 and 350 tex. 10. A composite yarn according to any one of the preceding claims, in which the thread (4) having the lower count has a greater resistance to the predetermined dye than the other thread or threads (2) . 11. A method of making a composite stipple yarn comprising the step of forming a composite yarn in accordance with any one of the preceding claims and subsequently overdyeing the composite yarn in the predetermined dye so that the thread (4) with the lower count has a different colour or shade to the other thread or threads (2) . 12. A method according to claim 11, in which the thread (4) with the lower count or the or each other thread (2) is treated to change its affinity to the predetermined dye. 13. A method according to claim 12, in which the treatment is a chemical treatment. 14. A method according to claim 13 , in which the chemical treatment comprises applying a generally colourless reactive dye to the thread (2,4) to fill the dye sites and prevent subsequent dyeing. 15. A method according to any one of claims 11 to 14, in which the thread (4) having the lowest count or the other thread or threads (2) are pretreated before they are formed into the composite fibre, for example by space dyeing or by heathering. 16. A method according to any one of claims 11 to 15, further comprising the step of setting the yarn before it is overdyed. 17. A carpet formed from composite stipple yarns according to any one of claims 1 to 10 or as manufactured in accordance with any one of claims 11 to 16.

Inventors: BEVERIDGE EDWARD, BEVERIDGE, EDWARD
Applicants: BEVERIDGE EDWARD, BRINTONS LTD, ETTRICK & YARROW SPINNERS LIMI, BEVERIDGE, EDWARD, BRINTONS LIMITED, ETTRICK & YARROW SPINNERS LIMITED
Application year: 1998
Main classification: D02G3
IPC codes: D02G3