EP0987358A1 - Method of manufacturing an elastic polyester fabric completely made of fibres - Google Patents

Abstract

In the production of a polyester fabric, where all the fibers have an elastic stretch, a proportion of the fibers are a bi-component type which can be shaped into spiral coils. The fiber preparation and spinning stages are for non-stretch filaments, and the fabric is strongly structured to take in its potential elasticity. For the production of a polyester fabric, where all the fibers have an elastic stretch, a proportion of the fibers are a bi-component type which can be shaped into spiral coils. The fiber preparation and spinning stages are for non-stretch filaments, and the fabric is strongly structured to take in its potential elasticity. The loomstate fabric is given an initial heat treatment in hot air at a temperature of 180-190 degrees C under a low fabric tension before conventional processing and finishing such as washing and dyeing. During all subsequent heating processes, the fabric tension is limited. For the initial heat treatment, the fabric is carrier by a stenter through a temperature of 185 degrees C for 1.0-1.5 minutes. The fabric is composed of polyester and wool fibers, in a 50:50 mixture, where all the polyester fibers have a bi-component structure. The stenter gives a stenter advance of 15% and a fabric width control at the stenter exit of 9% less than the width of the loomstate material. After dyeing, the fabric is dried at a stenter at a temperature of 130 degrees C after a heating stage at 185 degrees C. The fibers are mixed at the carding and spinning stages, without recombing. The polyester and wool fibers are taken from their bales, to be mixed by carding and combing to form tops followed by drawing at a drafting frame and spinning. During weaving, the warps are reduced by 15-20%. The bi-component polyester fibers have an elastic stretch of 15-20% in the warps and wefts. The cloth is composed of yarns number 2/70, in the warps and wefts. The bi-component polyester fibers are in two different cuts of 80 and 105.

Description

The present invention relates to a polyester fabric, all fibers, having elasticity properties in relatively large proportions significant, of the order of 15 to 20%, without the use of materials from the elastomeric type. It relates more particularly to a method of manufacture of such a fabric using polyester fibers bi-compound with bimetal structure capable of developing a helical crimp and spiral. It also relates to a fabric obtained by said process.

The use of textured threads makes it possible to obtain a polyester fabric with high elasticity but this use excludes of course that it is a all-fiber fabric, textured yarns being by nature continuous yarns. Being an all fiber polyester fabric, the elasticity can be conferred by using a certain proportion of elastomeric fibers, especially elastane. It has also been proposed to use fibers bi-composite with bimetal structure, i.e. synthetic fibers having two juxtaposed components having characteristics different chemical or physical, these differences causing subsequently a certain crimp of said fibers. In particular the RHONE-POULENC FIBERS company presented in 1984 a fiber polyester, called X403, of this type. It has a bimetal structure of which the two components, juxtaposed longitudinally, are chemically different polyesters, obtained from two diols different. According to the producer this fiber develops a crimp helical and spiral which gives it a swelling and extensibility, like what is obtained with textured threads, except that spun with fibers, whether pure or mixed, have no extensibility, the crimp and therefore the extensibility being revealed only during dyeing or various heat treatments performed on the fabric. More specifically, RHONE POULENC FIBERS recommended to carry out the following sequence of operations on the unbleached fabric, namely washing, heat treatment at 190 ° C for about 30 seconds, dyeing 130 ° C, skinning after dyeing, drying on reams, brushing / shaving and primer and finishing.

However, the applicant has found that by respecting scrupulously the above recommendations, he did not get a tissue finished which has an elasticity rate of 15 to 20%, as announced.

The goal set by the applicant is to propose a method of manufacturing which overcomes the aforementioned drawback, that is to say which allows obtain a polyester fabric under industrial conditions, all fibers, elastic with a certain proportion of polyester fibers bi-compound with bimetal structure, able to develop a crimp helical and spiral.

In known manner, the method comprises operations of preparation of the mixture of fibers, spinning, weaving and various tissue treatments.

Typically, the preparation and spinning leading to a non-extensible yarn and the fabric being strongly decontextured to take into account its potential elasticity, we submit the unbleached fabric at a heat pre-treatment, in hot air at a temperature between 180 and 190 ° C under very low voltage, prior to all conventional treatments in a liquid medium, especially washing and dyeing; moreover during all operations subsequent to the heat pre-treatment, the tension of the fabric is limited.

So, contrary to what was recommended by the producer, it is according to the applicant imperative that the first treatment that must undergoing the off-white fabric is a dry heat pre-treatment, any treatment preliminary aqueous in hot water of the washing type being to be avoided in the extent to which this results in a consequent loss of potential extensibility of the bi-composite fibers on the final product. This dry heat pre-treatment should be followed by precautions during subsequent treatments to limit tension exerted on the fabric.

Preferably the dry heat pretreatment consists of a rowing for a period of 1 minute to 1.5 minutes approximately at a temperature of the order of 185 ° C.

Being a 50/50 polyester / wool blend, all of which polyester fibers have a bimetallic structure, the passage in rowing is carried out with a rowing advance of around 15% and a width adjustment in oar output of the order of 9% weaker than the width of the unbleached fabric.

Furthermore, the applicant also found that the operations preparation of the fiber and spinning mixture could be a source of loss of tissue stretch potential. Being a fabric polyester / wool, conventionally, there are first operations carried out on each type of fiber leading to formation on the one hand woolen ribbons and on the other hand polyester ribbons; the fiber blend is made from these two types of ribbons - called tops - with a repainting operation integrated into the spinning mill.

Typically, according to the invention, the mixture of fibers is produced directly by carding and spinning is free repainting operation.

This particular operating mode has been determined by the applicant after having noticed that the repainting operation in spinning was likely to significantly lower the extensibility potential of the tissue if not followed by sufficient relaxation time. In practice it is difficult to reliably ensure absolute compliance with this time rest so it was deemed opportune to delete purely and simply the repainting operation in spinning by implementing a different preparation circuit in which the mixture of the fibers of bi-compound polyester and wool is carded out of a mixer fed with bales of fiber fluff.

The present invention will be better understood on reading the description which will be given of a preferred embodiment of a fabric polyester all fibers of the order of 50/50 in which the fibers of polyester are bi-composite fibers with a bimetal structure developing a spiral helical crimp.

The bi-composite fiber with bimetal structure which will be discussed in this description is the polyester fiber sold under the name X403 by the company RHONE-POULENC FIBERS. The current invention is not however exclusive of this fiber and can be applied any bi-composite polyester fiber of the same type, able to develop a helical and spiral crimp, approaching the natural crimp of wool.

According to the traditional yarn preparation and spinning circuit polyester / wool of the order of 50/50, the blend of polyester fibers and wool fibers are made from ribbons, called tops.

To achieve the formation of these tops, the fibers of wool and polyester are subjected to parallel operations, including carding and combing for wool. Mixed tops are, before spinning, repainted before the doubling operations on gills, then the passage on a spindle bench and finally on continuous spinning. In as part of the process of the invention, using the fibers of bi-composite polyester with bimetal structure called X403, the circuit above mentioned has been replaced in order to avoid the repainting operation before spinning which, according to the findings of the is likely to thwart the potential for scalability of polyester fibers on the finished fabric, after revealing the crimp. In effect if we implement the conventional circuit mentioned above, it must wait a determined time of rest of the ribbon thus repainted to obtain the optimal characteristics of tissue extensibility. If this time is not respected, these optimal characteristics are not reached. As the time in question can itself vary depending on the operating conditions and that moreover this imposes a constraint unacceptable, the applicant has determined conditions that are industrially acceptable and which overcome the aforementioned drawback.

Characteristically according to the invention, the mixture polyester / wool is carded from fibers from a fiber feed mixer. The circuit is therefore as follows. We make a premix, in a mixer, from bales of polyester fibers X403 on the one hand and wool fibers on the other. In a specific and preferred example, the mixture is made from two kinds of polyester balls X403, different cuts: some of section 80 and the others section 105. The mixer has means for working the material, for example a beating comb, weighing means and means of transport to supply the cards in the right proportion of polyester and wool fibers. These fibers are subjected to successive carding and combing leading to the formation of tops, then to the operations of doubling on gills, passing on a spindle bench then on continuous spinning.

The yarn produced at this stage has no extensibility, the crimping of polyester X403 which has not yet been revealed. On the other hand weaving operations must take into account the potential elasticity of the finished fabric. This fabric should be, during weaving, strongly decontextured so as to leave room for the strong withdrawal that will have to operate the threads later, when the crimp is revealed.

In a specific embodiment, the fabric, of plain weave, consisted of wires Nm 2/70 (286dtex) in warp and weft. It included 19.5 picks / cm in the weft (instead of 23 picks / cm usual) and in 3485 thread chain for a width of 180cm (instead of 4100 usual sons). The fabric was therefore decontextured on the order of 17.6% in warp and weft, knowing that the extensibility sought should be in the range of 15 to 17%.

Being strongly decontextured, the ecru fabric must be handled with care, especially during unwinding, during operations subsequent.

This off-white fabric is typically subject to according to the method, a dry heat pre-treatment, in the form of a rowing at a temperature between 180 ° C and 190 ° C, preferably 185 ° C. It is during this heat pre-treatment that develops the helical and spiral crimp of X403 polyester fibers. The fabric fits from 6 to 8%. The rowing in question was conducted with minimum tension setting, 15% feed and setting width leading to a width of approximately 170cm for the ecru fabric at 156 cm at the end of the train.

Since this heat pre-treatment is not preceded by washing the unbleached fabric, it is important to be particularly vigilant to cleanliness during weaving, this pre-treatment can fix certain soiling.

• lavage continu ou discontinu,
• teinture sur matériel overflow à environ 110°C,
• séchage en rame à 130°C,
• premier traitement thermique sur tissu sec à 185°C, la rame est réglée avec une avance de 15% et un réglage en largeur jusqu'à 150cm du tissu en sortie de rame,
• rasage,
• vaporisage et relaxation sur tapis vibrant,
• second traitement thermique à sec par passage en rame à 185°C. La rame est réglée avec une avance de 15% et un réglage en largeur jusqu'à 145 cm de laize en sortie de rame,
• décatissage.

The thermal pre-treatment is followed by conventional operations which do not require any particular precaution except to limit as much as possible the tensions exerted on the fabric. The operations include the following:

• continuous or discontinuous washing,
• dyeing on overflow material at around 110 ° C,
• row drying at 130 ° C,
• first heat treatment on dry fabric at 185 ° C, the ream is adjusted with an advance of 15% and a width adjustment up to 150cm of the fabric at the output of the ream,
• shaving,
• spraying and relaxation on a vibrating mat,
• second dry heat treatment by rowing at 185 ° C. The train is adjusted with an advance of 15% and a width adjustment up to 145 cm in width when leaving the train,
• decatising.

It should be noted that ream drying at 130 ° C is considered by the applicant as an important step, before the first treatment thermal, to obtain the optimization of the extensibility which is wanted.

The finished fabric has a width which in the end is around 142 - 143 cm and an extensibility of 15 to 16% in chain and from 16 to 17% in frame.

The present invention is not limited to the precise mode of realization which has just been given by way of non-exhaustive example. he can be all-fiber fabrics containing other types of fibers than wool, mixed with bi-compound polyester with bimetallic structure, as well than other mixing ratios.

Claims (10)

Method for manufacturing a polyester fabric, all fibers, elastic containing a certain proportion of bi-composite polyester fibers bimetal structure, able to develop a helical and spiral crimp, said process comprising operations for preparing the mixture of fibers, spinning, weaving and various fabric treatments, characterized in that the preparation and spinning operations leading to a non-stretchable thread and the fabric being strongly decontextured to take into account its potential elasticity, we submit the unbleached fabric at a heat pre-treatment, in hot air at a temperature between 180 and 190 ° C under very low voltage, prior to all conventional treatments in a liquid medium, especially washing and dyeing, and in that during all operations subsequent to the heat pre-treatment, the tension of the fabric is limited. Method according to claim 1 characterized in that the pre-treatment dry thermal consists of a period of rowing for a period from 1 to 1.5 minutes approximately at a temperature of the order of 185 ° C. Method according to claim 2 characterized in that, as regards a polyester / wool blend of the order of 50/50 including all the fibers polyester are bimetal structure, the passage in oar is carried out with a rowing advance of around 15% and a width adjustment at the outlet of ream of the order of 9% weaker than the width of the unbleached fabric. Method according to one of claims 1 to 3 characterized in that, after the dyeing operation, the fabric is dried by reaming at 130 ° C before being subjected to a heat treatment, at 185 ° C. Method according to one of claims 1 to 4 characterized in that the mixture of fibers is carried out directly with the card and the spinning is free from repainting. Method according to claim 5 characterized in that the operations preparation and spinning consist in carrying out a premix, in a mixer, from bales of structured polyester fibers bimetallic strip on the one hand and wool fibers on the other, to submit these fibers in successive carding and combing operations leading to the formation of tops, then to the dubbing operations on gills, passing on a spindle bench then on continuous spinning. Method according to one of claims 1 to 6 characterized in that for the weaving operation, the number of warp threads is reduced and the number of picks of the order of 15 to 20%. Elastic polyester / wool fabric of the order of 50/50, all fibers, whose polyester fibers are bi-composite fibers with a bimetal structure, having an elasticity in warp and weft of 15 to 20%. Fabric according to claim 8 having a plain weave, and consisting of son Nm 2/70 in warp and weft. Fabric according to one of claims 8 or 9, characterized in that bi-composite polyester fibers with bimetal structure are two cuts different, especially 80 and 105.