EP0441726A1 - Non-woven in synthetic filaments which have one part with modified surface properties, manufacturing process and their applications - Google Patents

Abstract

Nonwovens of synthetic continuous filaments obtained by melt extrusion, in which at least 50% of the filaments contain at least from 0,5 to 3%, preferably from 0.6 to 1.5%, of a polyorganosiloxane introduced into the said filaments during their manufacture. Process for the manufacture of these nonwovens, in which, before extrusion of the polymer melt to produce the filaments by flowing through orifices of a die, a silicone oil of polyorganosiloxane type is introduced in the proportion at least of 0,5 to 3%, preferably from 0.6 to 1.5% relative to the polymer, into the melt of the latter. The polyorganosiloxane product employed is of the polydiorganosiloxane type with a molecular weight of between 1,000 and 250,000, preferably between 7,500 and 70,000, corresponding to dynamic viscosities of 50 to 10,000 mPa s; stable under extrusion conditions. Use of the nonwovens, chiefly as a support for floor coverings with stitched pile.

Description

The present invention relates to nonwovens of synthetic continuous filaments, at least part of which have modified surface properties, their manufacturing process and their applications.

The present invention relates more particularly to nonwovens of continuous filaments used as backing for floor coverings or carpets with quilted or tufted pile, at least part of said filaments having a modified surface, thus facilitating the penetration of needles during the stitching of pile threads. in the background.

The use of nonwovens of continuous filaments, generally of polypropylene or polyester as funds or supports for stitching bristles is well known.

The polyester supports are used in particular when one wishes to produce particularly stable carpets such as carpet tiles or carpets printed in strips with prints with patterns connectable from one strip to the other, again requiring supports high dimensional stability both during processing: stitching, dyeing, printing, reverse coatings ... and for their behavior after installation. They are also used for the manufacture of moldable tufted carpets for automobiles because of their good elongation at break, their resistance to tearing as well as for their good thermal resistance.

However, the stitching of the wires in said supports poses problems. Indeed, the penetration of the needles causes breakage of strands, of filaments, weakening the mechanical properties of the backrest and, thereby, causing disturbances during manufacture and defects on the bottom of the article, detrimental to its solidity. , therefore to its subsequent use under normal conditions.

In order to remedy this technical problem, the solution most often proposed consists in spraying the nonwoven or the filaments during their manufacture with a lubricating product; the nonwoven as well lubricated thus being able to be penetrated by the needles without damage during the pricking of the hairs. Such processes are described, for example, in the French patent applications published under Nos. 2,174,290 and 2,245,807, in which a polysiloxane type product is used.

These processes require, for the spraying of the product, the implementation of additional installations used during the manufacture of the nonwoven and continuously with the latter, or after the manufacture of the latter subsequently, hence complications and additional handling costs. .

The object of the present invention is to propose a manufacturing process, presenting a simple, economical answer to the problem posed of maintaining the qualities of the nonwovens during their penetration by needles during the stitching of the hairs.

The subject of the present invention is nonwovens of synthetic continuous filaments obtained by melt extrusion, characterized in that at least 50% of the filaments contain from 0.1 to 3%, preferably from 0.5 to 1.5%, of a polyorganosiloxane introduced into said filaments during their manufacture.

The present invention also relates to a process for manufacturing the above nonwovens, characterized in that, before the extrusion of the polymer melt for the production of filaments by passing through the orifices of a die, a polyorganosiloxane type silicone oil in the proportion of 0.1 to 3%, preferably 0.5 to 1.5% relative to the polymer, in the molten mass thereof and for only at least 50% thereof .

The present invention also relates to the use of nonwovens thus obtained for the usual applications and more particularly as the background of floor coverings with pitted hairs.

The filaments can be of any polymer, copolymers or blends of synthetic polymers such as those based on polyester, polyolefin, polyamide. It is obvious that the polymers can be used alone or with others for the production of bimetallic filaments of the core-sheath or side / side type. It is also possible to use polymers of the same chemical nature but of different presentation: thus polyesters such as polyethylene terephthalate of butylene glycol, polyamides such as polyhexamethylene adipamide or polycaprolactam, polyolefins such as polyethylene or polypropylene; in the present invention it will be more particularly a question of the use of polymers based on polyester.

The polyorganosiloxane used is preferably chosen from oils such as polydiorganosiloxanes and, preferably, polydimethylsiloxanes with molecular weights from 1000 to 250,000 and preferably located between 7,500 and 70,000 corresponding to respective dynamic viscosities of 50 to 10,000 mPa.s. These oils are non-functionalized polydimethylsiloxanes. They are chemically and thermally stable at the melting / spinning temperatures of the polymer. The rate of introduction of silicone oil relative to the polymer can vary between 0.1 and 3%, preferably 0.5 to 1.5%.

It has been found that the quantities of product introduced into the melt do not practically disturb the conditions of extrusion, transfer, spinning and drawing of the filaments; the passage of the melt through the die orifices being thereby facilitated by this kind of lubrication provided by the product contained in the melt, part of which then exudes on the surface of the filaments forming a stable film.

The incorporation of the product into the polymer can be carried out before or during the polymer drying phase (discontinuous process in which one starts from polymers in the form of "granules" and which it is necessary to condition before use) by coating or by injection, or during or after the polymer melts in the body or the nose of the extruder, in general in any transfer zone of the molten polymer before its transformation into filaments.

The product can be introduced into the polymer stream feeding the extruder by means of a volumetric dosing pump. A mass dosage is, of course, entirely applicable to the operation.

The process used for the production of nonwovens of continuous filaments is of known type; one can for example use that described in the French patents published under No. 1,601,049 or No. 2,299,438 of the Applicant, the bonding of the sheet being effected by needling or thermobinding with or without resin.

The product can be introduced into the whole of the polymer or polymers used or only in a part of the latter, the preservation of the desired properties as regards the stability of the nonwoven and its ease of penetration by needles being carried out with at least 50% of the filaments containing the product. Thus it is possible to extrude two different polymers in the form of separate filaments or bimetal strips as mentioned previously, a part of the filaments in the first case or a single blade in the second case containing the product.

for carrying out the present invention, the nonwovens described in the French patent published under No. 2,546,537 of the applicant, in which two polymers based on polyester are used: polyethylene terephthalate polyterephthalate and polyterephthalate are preferably used butylene glycol.

The nonwovens of the present invention are used for all the usual textile or technical applications of nonwovens either alone or mainly as a support for nonwovens with stitched pile. They can be associated with other nonwovens and, possibly, reinforced with threads parallel to each other, preferably in the length direction; they can be subjected to any manipulation of embossing, forming, molding, impregnation, coating, etc ...

The various tests of which description below are used to differentiate the nonwovens of the invention from nonwovens containing no product in the mass of the filaments.

Needle penetration force measurement : a) In the laboratory

The penetration force measurement of a row of tufting needles in the sheet consolidated by thermobinding is carried out as follows:

3 strips of SINGER tufting needles serial number 82.753 each comprising 12 needles are welded side by side on the same line forming a row of needles 9 cm wide. This assembly is fixed on the mobile jaw of a dynamometer and penetrates (at the speed of 1000 m / min) into the fixed nonwoven surface stretched on a suitable device perpendicular to the movement of the needles.

b) On tufting machine

The test is carried out on a SINGER-COBBLE machine with 1/10 "gauge needles, using a continuous multifilament crimped 1100 dtex / 88 twist strand Z 150 x 2S 150 45, 40 points tightening, as a pile thread.

Dosage of the product introduced into the mass on filaments present in the nonwoven : a) Determination of the% of total silicone (core + surface of the filaments)

By ethoxylation and gas chromatography: attack in an alkaline medium of the nonwoven. This method makes it possible to individualize each atom of silicone while preserving its initial chemical environment. The analysis is then carried out by gas chromatography.

b) Determination of the% of silicone on the surface of the filaments

By extraction at 30 ° C with cyclohexane, then weighing the residue after evaporation of the solvent. The silicone is then measured in this extract corresponding to the various products found on the surface of the filament, mainly silicone and oligomers.

The following examples illustrate the present invention without limiting it:

Example 1 :

As described in the applicant's French patent, published under No. 2,546,537, a nonwoven web of 120 g / m² of continuous filaments is produced, containing 2 types of polyethylene glycol (2GT) (85%) and polybutylene glycol ( 4 GT) (15%), of respective titles 6 and 4 dtex, using for the depositing of the filaments the traveling method object of the French patent published under n ° 2.299.438 of the plaintiff.

Was introduced by metering pump, upstream of the extruder 2GT, 1% of silicone oil RHODORSIL 47 V 350 (polydimethylsiloxane of viscosity 350 mPa.s. relative to the weight of the granules of (2GT) from the company RHONE POULENC.

The tablecloth is needled on a single impact needle-punching machine at the rate of 50 perforations / cm² with SINGER needles of 40 Rb gauge 15 mm of penetration.

The sheet is then thermobonded by passing in "S" on a calender with two heating rollers at 230 ° C, the pressing force between the rolls is 12 daN / cm and the total contact time of the sheet on the hot rolls is 9 seconds, then cooled and rolled up.

The dosage of silicone oil which has exuded on the surface of the filaments gives a silicone content of 0.05% relative to the weight of the sheet. The amount of silicone relative to the weight of the sheet being 1%. The penetration force of the needles is, according to the laboratory test, 23.6 daN for the sheet without silicone and 15.7% daN for the sheet obtained as above indicating, without ambiguity, the difference in forces penetration and the advantage of using the silicone product.

On a tufting machine, the passage of the silicone-free tablecloth is impossible: breakage of filaments, total deterioration of the support after tearing while the silicone tablecloth leads to excellent tufting.

Tests were carried out according to the previous methods by full bath padding in an aqueous dispersion of silicone so as to have a dry deposit of 0.5% of silicone relative to the weight of the nonwoven: the results are of the same order as those obtained with the tablecloth containing a bulk silicone product. The economy of the process, however, argues in favor of the present invention.

The tufted carpet has mechanical properties and sufficient stability to be transformed, after coating bitumen on the back, into tiles for flooring.

Example 2 :

A nonwoven web of 120 g / cm² of continuous filaments of polyethylene terephthalate of title 7 dtex filament is produced, by the process indicated in example 1, taking care to introduce into the polymer 0.5% of silicone oil (polydimethylsiloxane with a viscosity of 1000 mPa.s) relative to the weight of the polymer.

The tablecloth is then needled with 40 RB needles from SINGER at the rate of 80 perforations / cm² and 13 mm of penetration on only one side.

A heat treatment is then carried out by hot calendering between 2 rollers heated to a temperature of 235 ° C. with a pressing force of 25 daN / cm and a contact time of 8 seconds.

This support can be tuffed without any problem and has all the required properties of solidity and deformability for the production of a moldable floor mat for cars.

Example 3 :

A nonwoven web of 115 g / m² of continuous filaments containing 2 types of filaments 2GT 88% and 4GT 12% of respective titles 9 and 5 dtex is produced by the method indicated in Example 1.

Was introduced by metering pump, in front of the extruder 2GT 1.5% RHODORSIL 47V2000 silicone oil (polydimethylsiloxane with viscosity 2000 mPa.s) relative to the weight of 2GT granules.

The tablecloth is needled on a single stroke needle-punching machine at the rate of 60 perforations per cm² with SINGER needles of 40 Rb gauge with a penetration depth of 14 mm. The sheet is then thermobonded by passing over a perforated air-passing drum at a temperature of 242 ° C with a contact time of 15 seconds and then calibrated using a calender with metal rollers heating to 230 ° C, spacing between rollers preset so as to adjust the density of the thermobonded web to 0.19, that is to say a thickness of 0.6 mm. This ply has all the properties of tuftability, mechanical properties and dimensional stability to make a floor covering support with pile stitched in strip and capable of being printed with patterns connectable from one strip to another.

Example 4 :

A nonwoven web is produced, by the process indicated in Example 1, composed of continuous filaments of 125 g / m² consisting of coaxial filaments whose core is made of polyethylene terephthalate and the sheath made of polybutylene glycol terephthalate.

The core represents 80% of the mass of the coaxial filament and the sheath 20%.

Care has been taken to introduce into the polymer 4GT constituting the sheath, and this at the nose of the extruder by means of a volumetric metering device, 0.8% of a 47V1200 silicone oil (polydimethylsiloxane of viscosity 1200 mPa .s) relative to the weight of polyester.

The titer of the coextruded filaments is 10 dtex.

The nonwoven web is then consolidated under the conditions of Example 3.

The thermally bonded support thus obtained will have all the properties of presentation, mechanical performance, tuftability and stability necessary for the production of a velvet carpet presented in the form of tiles.

Claims (7)

1 - Nonwovens of synthetic continuous filaments, obtained by polyester melt extrusion, characterized in that at least 50% of the filaments contain at least 0.5 to 3%, preferably 0.6 to 1.5%, of a polyorganosiloxane type oil introduced into the melt of the polymer during the extrusion. 2 - process for manufacturing the nonwovens object of claim 1, characterized in that, before extrusion of the polymer melt for the production of filaments by passing through the orifices of a die, a silicone oil type polyorganosiloxane is introduced into the proportion of at least 0.5 to 3%, preferably 0.6 to 1.5% relative to the polymer, in the melt thereof by injection after the polymer has melted in the nose of the extruder . 3 - process for manufacturing the nonwovens object of claim 2, characterized in that the introduction of silicone oil type polyorganosiloxane is carried out by injection during the melting of the polymer in the body of the extruder. 4 - process for manufacturing nonwovens according to one of claims 2 to 4, characterized in that several polymers are extruded and that the introduction of the silicone product is carried out in at least one of the polymers used. 5 - Nonwovens according to claim 1, characterized in that the polyorganosiloxane product used is of the polydiorganosiloxane type with a molecular weight of between 1,000 and 250,000, preferably between 7,500 and 70,000, corresponding to dynamic viscosities of 50 to 10,000 mPa.s, stable under extrusion conditions. 6 - Nonwovens according to claim 1, characterized in that they consist of at least 50% of polyethylene terephthalate filaments containing from 0.6 to 3% of an oil of polyorganosiloxane type and of less than 50 % of polybutylene glycol polyterephthalate filaments. 7 - Use of the nonwovens that are the subject of claim 1 as a support for quilted pile floor coverings.