Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-07-26
2002-08-13
Yao, Sam Chuan (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S179000, C156S254000, C156S269000, C028S159000
Reexamination Certificate
active
06432234
ABSTRACT:
SUBJECT OF THE INVENTION
The present invention relates to an improved method for the manufacture of textile products of the “lapped/bonded” type directly from fibres and/or from filaments.
The invention also relates to an apparatus for carrying out the method and to the products obtained by means of the said method.
PRIOR ART ON WHICH THE INVENTION IS BASED
So-called “lapped/bonded” products are products which are produced from a textile lap, preferably from a lap already consisting of threads, or, if appropriate, from a fibrous lap, which is subjected to a succession of foldings for the purpose of forming folds which may be likened, in the direction of advance of the lap, to loops. This folded lap is subsequently simply fixed to a support by adhesive bonding. A product is thus obtained, in which the threads and/or fibres do not pass through the support, in contrast to tufted products which take the form of a succession of loops passing through the support.
There are, at the present time, essentially two large families of methods intended for producing textile products of the “lapped/bonded” type.
The first family is the best known and comprises the methods employing a machine with arms, to which blades are fastened. A lap of threads is pushed by these blades successively onto a first backboard, then onto a second backboard which is parallel to the first, in order to form a succession of loops by folding. These loops are subsequently fixed to a support which is preferably coated beforehand with a glue, such as a polyvinylchloride paste, and onto which the loops will be deposited, the assembly thus formed by the support and the fixed loops being subsequently subjected to thermal treatment, for example passage through an infrared furnace.
According to another embodiment, the loops may be held between two supports, before a hot-melt adhesive passes through the said supports in order to impregnate the bases of the loops.
At all events, whether by fixing of the PVC type or of the hot-melt type, the product obtained either has a looped appearance resembling a looped tufted product or is of the “sandwich” type, consisting of loops trapped between two supports which may be subsequently split longitudinally in order to obtain two products of the pile fabric type.
Another alternative involves proposing the use of tensioned cables to replace the blades mentioned above.
According to the second large family of methods, successive folds are formed by means of a rotary system, by pushing the threads and/or fibres of the lap successively into protuberances present on a grooved cylinder. The folds are made under the action of a folding member, such as a blade or a roller, which are themselves grooved. Subsequently, a support, preferably coated beforehand with glue, is arranged on the succession of loops obtained by folding. If appropriate, the assembly consisting of the support and of the fixed loops is subjected to thermal treatment before these are removed from the grooved cylinder.
It is expedient to note that all these methods have the following disadvantages:
their production speed remains relatively low. As an example, 120 strokes per minutes is already a relatively high speed for a system with arms, as described above, because of the complexity of the movement generated by the cam members;
the quantity of adhesive necessary for fixing the loops to the support remains large, and therefore the products obtained are still relatively too costly;
the range of products of the “lapped/bonded” type which can be produced is relatively limited.
On the other hand, the Applicant developed a technique for producing textile products directly from fibres and/or filaments, which is called the “verticalization technique”.
This technique is described in the patent application published under number WO91/00382, and makes it possible to produce products, such as floor and/or wall coverings of the moquette type, directly from fibres and/or filaments travelling in the form of a web.
The technique described involves subjecting the fibres and/or filaments to “transverse looping” accompanied by “drawing” and obtaining an accumulation of fibres and/or filaments in the form of a crimped “pseudo-yarn”, in which the fibres and/or filaments are parallelized. This step is referred to, in general terms, as the “(pre)looping step” and must not be likened to folding.
This document describes that transverse looping accompanied by drawing is carried out, for each individual fibre or filament, by means of rotary elements or looping discs which are spaced and arranged on a shaft transverse to the direction of advance of the web and between which looping fingers are arranged. Each fibre or filament is, in principle, thereby involved in at least one looping. A non-twisted pseudo-yarn is thus formed, obtained by the accumulation of the various exactly parallelized elementary fibres and/or filaments, the said accumulation having a looped form.
The accumulation of the parallelized fibres and/or filaments in the form of the pseudo-yarn takes place either in the open needle eye, as described in detail in the Applicant's publication WO91/00382, or in notches provided in transfer elements, as described in the document WO96/10667, also of the Applicant.
With the aid of these transport members consisting either of the needles or of the transfer elements, the pseudo-yarn is subsequently transported, in the form of transverse rows of loops, towards a support to which the loops are fixed.
In the publication WO91/00382, fixing is carried out by passing the needles through this support for the purpose of producing, more specifically, a floor covering of the tufted type.
This method was made even better by proposing the improvements described in European Patent Application EP 95870093.2, in which the method described in the publication WO91/00382 is combined with the use of a lap drawframe, as described in the document EP-A 0,520,911. Moreover, it is proposed to double the looping elements by adding a step called the “crimping step”, so as to limit the forces on the shafts which arise as a result of the use of a web coming from a conventional lapper.
In this case, there are at least two separate assemblies of elements: the first assembly is intended for carrying out a crimping step by means of an apparatus consisting of the interpenetration of a first set of crimping discs with a first set of crimping fingers, whilst the second assembly is intended for carrying out the conventional subsequent step, called the prelooping step, by means of an apparatus consisting of the interpenetration of a second set of discs, called looping discs, with a second set of fingers, called looping fingers, this second assembly being arranged downstream of the crimping device in relation to the direction of advance of the web. The gauge of the crimping apparatus is a multiple of the gauge of the prelooping apparatus.
The products proposed in this document are essentially in the form of tufted products.
At this stage, it has been possible for this verticalization technique actually to achieve industrial use. In fact, it has been possible to control the levels of forces and torques even in the case of very large working widths (for example, greater than 4 meters).
Nevertheless, although this method can be fully put into practice on an industrial scale, it must be accepted that its productivity still remains limited. This is essentially due to the presence of transport members which execute an alternating movement and which are either in the form of needles or else in the form of transfer elements, as described in the document WO96/10667.
In fact, the production speed, which may be expressed as the product of the advance of the substrate per stroke (in mm) and the beating speed of the needles (in strokes per minute) reaches an order of magnitude of 1.5 to 4.5 m/min, this being perfectly acceptable for producing tufted products, but still remaining too low for production comparable to a needling line, the production speed of which may reach an order of 15 m/min
Alix Yale & Ristas, LLP
Tarkett Sommer S.A.
Yao Sam Chuan
LandOfFree
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