GB2071163A

GB2071163A - Dyeing yarns

Info

Publication number: GB2071163A
Application number: GB8001708A
Authority: GB
Original assignee: Lowe & Carr Ltd
Current assignee: Lowe & Carr Ltd
Priority date: 1980-01-18
Filing date: 1980-01-18
Publication date: 1981-09-16

Abstract

A method of dyeing yarns, which comprises feeding a continuous paper tape 6 printed with a vapour phase transfer printing ink, together with a complementary paper tape 8 that is optionally also printed with a vapour phase transfer printing ink, through a rotary transfer printing machine under conditions to effect transfer printing, and feeding one or more yarns 9 continuously through the machine between the paper tapes. The yarn or yarns are thus dyed by a solvent-free process that is both fast and economical. The tapes may be printed with patterns or be uniformly printed; inks may be the same color or different on the two tapes. <IMAGE>

Description

SPECIFICATION Dyeing yarns The invention relates to the dyeing of yarns.

Conventional methods of yarn dyeing involve the use of large and expensive dye vats and drying equipment, and rely on the availability of large quantities of water or, in some cases, organic solvents. It has long been desired to provide a method of dyeing that is capable of being utilized economically on a small scale without consuming large quantities of water. Such a method would be useful to, for example, knitting mills which may be located in arid areas a considerable distance from the large dyeing centres.

The invention provides a method of dyeing yarns, which comprises feeding a continuous paper tape printed with a transfer printing ink, together with a complementary paper tape, through a rotary transfer printing machine under conditions to effect transfer printing, and feeding one or more yarns continuously through the machine between the paper tapes. If desired a large number of yarns may be fed together through the transfer printing machine between the paper tapes. The transfer printing conditions cause the dye in the transfer printing ink to sublime onto the yarns, which emerge in their fully dyed state.

Preferably the rotary transfer printing machine is a narrow machine of the kind developed for the transfer printing of ribbons, and comprises a heated rotary drum and a stationary platen, the platen being covered with a continuous loop of flexible material (known as the blanket) which moves over the platen in register with the drum.

Although the method of the invention is expensive in dyestuff in that considerably less than all the dyestuff ends up on the yarns, it is nevertheless commercially very attractive as it enables yarns to be dyed continuously even on a small scale. Most important is the advantage that the process uses no water and is therefore equally capable of being used in arid or in non-arid areas.

Uniform dyeing of the yarns may be achieved by using, as the complementary paper tape, a paper tape printed with a transfer printing ink of the same colour or shade as that of the first tape.

The thermal insulation provided by the yarns that are sandwiched between the tapes is very slight (much less than if a knitted or woven fabric were interposed between the tapes) so that the complementary tape is heated indirectly via the first paper tape. This indirect heating is however sufficient to cause the dyestuff in the transfer printing ink on the complementary tape to sublime onto or into the yarns.

Special effects can be achieved in the dyeing method of the invention by using, as the complementary paper tape, a tape of undyed paper or a tape dyed with a transfer printing ink of a different colour or hue to that of the first tape. In the former case, the yarns take the dye more intensely on the side adjacent the dyed tape so that the finished yarns show a variation in dye concentration from one side to the other. In the latter case the yarns show a variation in colour or hue from one side to the other.

Other special effects can be achieved by having the paper tape and/or the complementary tape dyed in a pattern, such as stripes, to provide colour variations along the length of the yarn.

The yarns that may be dyed by the method of the invention include all of those that accept a vapour phase transfer dye, and include polyester, polyamide, acrylic and triacetate yarns.

Drawing The drawings is a schematic elevation of a rotary transfer printing machine being used in accordance with the method of the invention.

In the drawing, the rotary transfer printing machine comprises a rotary heated drum 1 around which is a part-cylindrical platen 2. Between the drum 1 and the platen 2 is a loop of blanket 3 which moves with. the drum past the platen and then follows a return path 4 until it again passes between the drum and platen.

A first roll 5 of transfer printing paper 6, about 3.5 cm (1.5 inches) wide, feeds its paper into the nip between the drum 1 and the blanket 3, and a complementary roll 7 of transfer printing paper 8 of the same width feeds its paper into the nip between the paper 6 and the blanket 3. The papers 6 and 8 are fed so that their printed sides are facing one another.

Yarns 9 are fed from a row of cones 10 (only one being shown in the drawing) between the paper tapes 6 and 8 to be re-wound at all.

Toothed combs 12 and 13 are provided on opposite sides of the drum 1 to maintain the yarns 9 in straight parallel paths through the nip and prevent entanglement.

The temperature of the heated drum 1 and the dwell time of the yarns 9 in the nip, determined by the speed of rotation of the drum, are chosen in relation to the dyes used. It is thus possible to achieve a good and fast dyeing in a single pass on a continuous basis, with the particular advantage that the process consumes no water.

1. A method of dyeing yarns, which comprises feeding a continuous paper tape printed with a transfer printing ink, together with a complementary paper tape, through a rotary transfer printing machine under conditions to effect transfer printing, and feeding one or more yarns continuously through the machine between the paper tapes.

2. A method according to claim 1, wherein the complementary paper tape is also printed with a transfer printing ink.

3. A method according to claim 2, wherein the paper tape and the complementary paper tape are printed with the same transfer printing ink.

4. A method according to claim 2, wherein the paper tape and the complementary paper tape are printed with inks of different shades or colours.

5. A method according to claim 1, wherein the complementary paper tape is unprinted.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Dyeing yarns The invention relates to the dyeing of yarns. Conventional methods of yarn dyeing involve the use of large and expensive dye vats and drying equipment, and rely on the availability of large quantities of water or, in some cases, organic solvents. It has long been desired to provide a method of dyeing that is capable of being utilized economically on a small scale without consuming large quantities of water. Such a method would be useful to, for example, knitting mills which may be located in arid areas a considerable distance from the large dyeing centres. The invention provides a method of dyeing yarns, which comprises feeding a continuous paper tape printed with a transfer printing ink, together with a complementary paper tape, through a rotary transfer printing machine under conditions to effect transfer printing, and feeding one or more yarns continuously through the machine between the paper tapes. If desired a large number of yarns may be fed together through the transfer printing machine between the paper tapes. The transfer printing conditions cause the dye in the transfer printing ink to sublime onto the yarns, which emerge in their fully dyed state. Preferably the rotary transfer printing machine is a narrow machine of the kind developed for the transfer printing of ribbons, and comprises a heated rotary drum and a stationary platen, the platen being covered with a continuous loop of flexible material (known as the blanket) which moves over the platen in register with the drum. Although the method of the invention is expensive in dyestuff in that considerably less than all the dyestuff ends up on the yarns, it is nevertheless commercially very attractive as it enables yarns to be dyed continuously even on a small scale. Most important is the advantage that the process uses no water and is therefore equally capable of being used in arid or in non-arid areas. Uniform dyeing of the yarns may be achieved by using, as the complementary paper tape, a paper tape printed with a transfer printing ink of the same colour or shade as that of the first tape. The thermal insulation provided by the yarns that are sandwiched between the tapes is very slight (much less than if a knitted or woven fabric were interposed between the tapes) so that the complementary tape is heated indirectly via the first paper tape. This indirect heating is however sufficient to cause the dyestuff in the transfer printing ink on the complementary tape to sublime onto or into the yarns. Special effects can be achieved in the dyeing method of the invention by using, as the complementary paper tape, a tape of undyed paper or a tape dyed with a transfer printing ink of a different colour or hue to that of the first tape. In the former case, the yarns take the dye more intensely on the side adjacent the dyed tape so that the finished yarns show a variation in dye concentration from one side to the other. In the latter case the yarns show a variation in colour or hue from one side to the other. Other special effects can be achieved by having the paper tape and/or the complementary tape dyed in a pattern, such as stripes, to provide colour variations along the length of the yarn. The yarns that may be dyed by the method of the invention include all of those that accept a vapour phase transfer dye, and include polyester, polyamide, acrylic and triacetate yarns. Drawing The drawings is a schematic elevation of a rotary transfer printing machine being used in accordance with the method of the invention. In the drawing, the rotary transfer printing machine comprises a rotary heated drum 1 around which is a part-cylindrical platen 2. Between the drum 1 and the platen 2 is a loop of blanket 3 which moves with. the drum past the platen and then follows a return path 4 until it again passes between the drum and platen. A first roll 5 of transfer printing paper 6, about 3.5 cm (1.5 inches) wide, feeds its paper into the nip between the drum 1 and the blanket 3, and a complementary roll 7 of transfer printing paper 8 of the same width feeds its paper into the nip between the paper 6 and the blanket 3. The papers 6 and 8 are fed so that their printed sides are facing one another. Yarns 9 are fed from a row of cones 10 (only one being shown in the drawing) between the paper tapes 6 and 8 to be re-wound at all. Toothed combs 12 and 13 are provided on opposite sides of the drum 1 to maintain the yarns 9 in straight parallel paths through the nip and prevent entanglement. The temperature of the heated drum 1 and the dwell time of the yarns 9 in the nip, determined by the speed of rotation of the drum, are chosen in relation to the dyes used. It is thus possible to achieve a good and fast dyeing in a single pass on a continuous basis, with the particular advantage that the process consumes no water. CLAIMS

6. A method according to any preceding claims, wherein the rotary transfer printing machine has a heated drum and an unheated non-rotary platen.

7. A method of drying yarns, substantially as described herein with reference to the drawings.