EP1314366A1 - Method for making a fusible interlining with dots of thermally fusible polymer and thermally fusible polymer used thereby - Google Patents

Abstract

Production of a heat-bondable stiffener comprises depositing spots of heat-meltable polymer (I) on the front of a textile or nonwoven substrate and subjecting the back of the substrate to electron bombardment. <??>Production of a heat-bondable stiffener comprises depositing spots of heat-meltable polymer (I) on the front of a textile or nonwoven substrate and subjecting the back of the substrate to electron bombardment, where (I) has functional groups capable of generating and/or reacting with free radicals under electron bombardment and the depth of penetration of the electrons into the polymer spots is controlled to produce self-crosslinking of (I) over a thickness less than the mean thickness of the spots. <??>An Independent claim is also included for a polymer of type (I) for carrying out the above process.

Description

The present invention relates to the field of interlinings fusible which are supports, textile or non-woven, on a on which are applied points of hot melt polymer, likely to adhere later on the piece of clothing to strengthen under the effect of the application of some hot pressure. It relates more particularly to a method of manufacturing such interlining using electronic bombardment in view to modify locally the melting temperature and / or the viscosity of the hot melt polymer; it also relates to a polymer hot melt specially designed for the implementation of said process.

Of all the problems encountered in the field of fusible interlining, one of the most delicate to solve is in the risk of penetration of the interlining support during the application by hot pressure of fusible interlining against the piece of clothing to reinforce. Indeed the temperature that is chosen to perform this hot application should allow to carry out the melting of the polymer point so that the polymer thus melted can be distributed and adhere to the fibers or filaments on the surface of the piece of clothing. It happens however frequently that this distribution is not only surface but that the molten polymer is flowing through the fibers or filaments and appears on the opposite side of the interlining support. This does not affect aesthetically, unless the stabilizer is intended to be apparent and to form the back side of the garment. In any event this piercing has the effect of increasing locally the rigidity of the interlining and therefore the piece of clothing, which may be contrary to the desired effect. It can also cause collages on dubbing fabrics such as lining and part of draperies in reverse, which causes a degradation of the quality of the garment.

To solve this problem, it has already been proposed to realize a fusible interlining whose points of thermofusible polymer have two superimposed layers, namely a first layer in contact with the face of the interlining support and a second layer arranged precisely above the first. Good sure the constituents of the two layers are determined so that when application with hot pressure of the piece of clothing, only the thermofusible polymer of the second layer reacts to the action of temperature. The diffusion of the hot-melt polymer can in this only to the piece of clothing, being prevented from interlayer support, the first layer acting as kind of barrier.

In practice this technique with two superposed layers has drawbacks, in particular the difficulty of carrying out the layering of both layers and risk of delamination of both layers.

To overcome these disadvantages, the applicant has already proposed in document FR.2.606.603 to implement means of a chemical nature, acting on the hot-melt polymer to change its chemical structure, at least partially, to less at the interface with the interlining support, so as to prevent the hot-melt polymer from sticking through the support of interlining under the effect of heat and / or pressure and / or steam. The means, of a chemical nature, capable of modifying the chemical structure of the hot melt polymer comprise at least a reactive material and at least one reactive means capable of starting, ensure, promote the reaction between the reactive material and the polymer melt.

The contacting between the reactive material and the polymer hot melt is either by mixing these two elements that are deposited in the form of dots, in an intimate mixture, on the interlayer support, either by application of the reactive material on the interlining support before depositing the polymer dots (then free of reactive material). Among the reactive means, are cited the heat inputs, ultraviolet radiation and bombardment electronic.

The applicant also proposed in the document EP.0.855.146A1 a method according to which one deposits on the face location a interlining support of hot melt polymer dots of average thickness E and containing a radical activator and submits one of the faces of the support to an electronic bombardment by adjusting the penetration depth of the electrons in the points of the hot-melt polymer to obtain a modification of physicochemical properties of the hot-melt polymer, chosen among the melting temperature and the viscosity, on a thickness e by compared to the average thickness E.

The radical activator has the function of creating radicals free to initiate the polymerization reaction on itself thermofusible polymer. It is not strictly speaking a reactive material in the sense of the document FR.2.606.603.

The techniques taught by the two aforementioned documents have various disadvantages. According to the document FR.2.606.603, when the reactive material is applied to the interlining support before the deposition of the polymer points, the reaction that takes place after the implementation of heat input, UV irradiation or electron bombing is done at the interface between matter reactive and the hot melt polymer. This reaction does not intervene only on a very small thickness. In all other cases the material reactive according to the document FR.2.606.603 or the radical agent according to EP.0.855.146A1 is mixed with the hot melt polymer before depositing points on the interlining support. This mixture is usually made during the dispersion of the polymer under form of a paste, the reactive material or the radical agent being then incorporated like any other product of the formulation. To get an even more intimate mix, according to the document EP.0.855.146A1, the mixing of the thermofusible polymer and the radical activator, this mixing with successive operations of fusion, extrusion and grinding so as to obtain a powder which is used as it is for coating or that is diluted for the subsequent preparation of the aqueous dispersion in the form of a paste for depositing the points of polymer on the interlining support. However, whatever the Intimate nature of the mix, there is always in every point applied on said interlining support on the one hand a polymer hot melt which brings the bonding function that is needed for the adhesion of the interlining support on the piece of clothing to reinforce and on the other hand a reactive material or a radical agent which brings a function of reactivity under the action of the means reagents such as heat input, UV irradiation or electronic bombing, the latter in particular as regards a radical agent.

In the particular case of a method of manufacturing a fusible interlining using a bombardment electronics to modify the chemical structure of the polymer thermofusible, the presence of the radical agent induces a certain number of difficulties. When the technique of depositing points of polymer uses an aqueous dispersion in the form of a paste, it is important to obtain a good stability of the dough in time that the components used in the formulation of the dough are soluble in water. Or products suitable as agents radicals are for the most part insoluble in water at least in the proportions in which they intervene in the preparation of the aqueous dispersion, which can cause a relative instability dough in time. In addition the products suitable as radical agents are usually in liquid form, with boiling temperatures that can possibly be incompatible with the temperatures used in the conditions procedures implemented when depositing points on the support interlining. So in this case there may be partial evaporation of the radical agent, which leads to a loss or even a disappearance of responsiveness to electronic bombardment. Finally he It has also been noticed that since the products as radical agents are usually monomers of low molecular weight, their behavior in mixing with the Hot melt polymer is comparable to that of a plasticizer. This behavior can cause a change in the melt viscosity of the hot-melt polymer, can pose quality problems, coating and can also change the strength properties intrinsic mechanics of the polymer and thereby influence the collage performance.

The aim of the applicant is to propose a method of manufacturing a fusible interlining an electronic bombardment to modify the structure chemistry of the hot-melt polymer that overcomes the disadvantages supra.

This goal is perfectly achieved by the method of the invention, according to which in known manner is deposited on the face place of a interlining support, selected from textile supports and nonwovens, hot melt polymer dots and subject the face of the interlining support to an electronic bombardment. Typically, according to the invention, the polymer points thermofusible are based on at least one functional polymer having functional groups capable of reacting with free radicals generated under the action of electronic bombing and / or themselves generators of free radicals under the action of electronic bombing; in addition, the depth of electron penetration into the polymer points to obtain, thanks to said functional groups, a self-crosslinking of said functional polymer on a limited thickness e with respect to the average thickness E of the polymer points.

Thus all the aforementioned drawbacks relating to the mixing of the thermofusible polymer and the radical agent are eliminated since it is the thermofusible polymer itself that includes both the adhesion function and the bombardment reactivity function electronic.

It is another object of the invention to provide a thermofusible polymer for fusible interlinings, especially designed for the implementation of the aforementioned method. This polymer thermofusible is characterized in that it comprises groups functional groups able to react with free radicals under the action of a electronic bombardment and / or themselves generators of free radicals under the action of electronic bombardment.

According to a first version, these functional groupings have functions with ethylenic unsaturation, for example acrylate, methacrylate, allyl, acrylamide, vinyl ether, styrenic, maleic or fumaric.

According to a second version, said groupings functional entities include labile entities, that is entities whose binding energies are lower than the usual connections carbon - carbon or carbon - hydrogen. As an example of an entity labile, there may be mentioned a carbon-chlorine bond C-CI or a bond thiol S-H.

Functional Hot Melt Polymers According to the Invention are obtained according to the two possible ways. According to the first way, we add directly, in the synthesis reaction medium of the polymer, monomers carrying the functional group or groups able to react with free radicals under the action of a electronic bombardment and / or themselves generators of free radicals under the action of electronic bombardment. According to second way, we start from the already formed hot melt polymer and it is later transformed by grafting onto its polymer structure functional groups desired by grafting techniques known.

The location of the functional group along the polymer chain significantly influences the reactivity of the polymer functional under the action of electronic bombardment as well as the structure of the crosslinked network obtained. The functional group can be located at the end of the chain, included along the chain or located on ramifications or grafts along the polymer chain main.

The functional thermofusible polymer according to the invention must necessarily have the properties of adhesion or bonding necessary for the intended use which is fusible interlining. Of the more it must be functionalized either during its synthesis or by subsequent transformation, as indicated previously. It is therefore especially polyethylene (PE), copolyamide (coPA), polyester (Pes), polyurethane (PU) or copolyamide block ether (PBAX). As non-limiting examples with regard to a skeleton of the polyamide type the functional groups are located at the end of the chain; regarding of a skeleton of the polyethylene type, the functional groups are located on branches along the main chain; in the case of a skeleton of the polyester type, the groups functional are included along the main chain; in the case of a skeleton of the polyurethane type, the functional groups are grafted along the main chain.

Of course the functional thermofusible polymer of the invention is selected so as to meet the constraints of use in fusible interlinings, constraints which are variables according to the techniques used.

In particular, as regards its presentation, this polymer must be delivered in the form of a grinding-resistant powder for particle sizes from 10 to 200 μm or to be available in granules if the technique used is of the hot-melt type.

When the deposit of polymer points is made from of an aqueous dispersion in the form of a paste, the polymer must be sure to be compatible for such an aqueous dispersion.

When the deposit is in the form of a coating, the functional groups that comprise the hot melt polymer must be stable at the coating temperature, knowing that the technique used, this temperature can range from 150 to 225 ° C. This thermal stability is essential to prevent functional groups give rise to an uncontrolled start of self-crosslinking. This thermal stability can be improved by incorporating into the functional hot melt polymer an antioxidant.

The melting temperature of the hot melt polymer functional of the invention, not subjected to bombardment electronic system, should generally be between 70 and 150 ° C, knowing that the melting temperature of the same self-crosslinked polymer under the action of electronic bombing him is higher.

The hot melt functional polymer of the invention is according to the applications, machine wash resistant, resistant to dry cleaning with chlorinated solvent and resistant to steam.

attachées à la chaíne carbonée. Il s'agit notamment du polymère EAA, proposé par la firme DOW CHEMICAL sous la dénomination Primacor 3150. On fait subir à ce polymère initial une réaction d'estérification avec un composé de type époxyde de formule :

proposé par la firme Aldricch sous l'appellation GMA, en proportion stachiométrique. On obtient le polymère fonctionnel de formule :

dont les groupements fonctionnels méthacrylates comportent des liaisons insaturées éthyléniques aptes à réaliser une auto-réticulation du polymère sur lui-même , grâce aux radicaux libres générés par l'action des élections lors du bombardement électronique. Il s'agit notamment d'un bombardement électronique réalisé avec une puissance d'au moins 70kV, avec une dose de l'ordre de 10 à 100 kGray sur la face envers du support d'entoilage dont la face endroit comporte des points formés avec le polymère fonctionnel. La puissance et la dose retenue permettent de limiter l'action des électrons sur une épaisseur e limitée de l'épaisseur moyenne des points déposés. Ainsi l'auto-réticulation du polymère fonctionnel ne se produit que sur cette épaisseur e du point, au niveau de la base dudit point, c'est-à-dire celle qui est en contact avec le support d'entoilage . Le polymère auto-réticulé a une température de fusion plus élevée que celle du polymère fonctionnel non-autoréticulé, de sorte que lors de l'application de l'entoilage sur l'article à renforcer la base auto-réticulée du point de polymère flue moins que le reste du point, ce qui évite le transpercement.According to an exemplary embodiment, the functional polymer has a polyethylene backbone and comprises functional groups of methacrylate type. To obtain this functional polymer is based on an initial polymer obtained from ethylene monomers and a small percentage, of the order of 3% by weight, of acrylic acid. This initial polymer of the polyethylene type contains acid functions

attached to the carbon chain. These include the EAA polymer, proposed by DOW CHEMICAL company under the name Primacor 3150. This initial polymer is subjected to an esterification reaction with an epoxide type compound of formula:

proposed by the firm Aldricch under the name GMA, in stachiometric proportion. The functional polymer of formula

whose methacrylate functional groups comprise ethylenic unsaturated bonds able to perform a self-crosslinking of the polymer on itself, thanks to the free radicals generated by the action of the elections during the electronic bombardment. This involves an electronic bombardment performed with a power of at least 70kV, with a dose of the order of 10 to 100 kGray on the reverse side of the interlining support whose face face has points formed with the functional polymer. The power and the dose used make it possible to limit the action of the electrons on a limited thickness e of the average thickness of the deposited points. Thus the self-crosslinking of the functional polymer occurs only on this thickness e of the point, at the base of said point, that is to say that which is in contact with the interlining support. The self-crosslinked polymer has a higher melting temperature than the non-self-crosslinking functional polymer, so that when applying the interlining to the article to reinforce the self-crosslinked base of the polymer point less than than the rest of the item, which avoids piercing.

A second and a third example of polymers functional polyethylene backbone can be cited.

proposé par la firme American Cyanamid sous la dénomination TMI, pour donner le polymère fonctionnel de forme générale :

In the second example, the functional groups are of the styrenic type. The initial polymer is obtained from ethylene monomer and of the order of 10% by weight of hydroxyethyl methacrylate. This may be the EHEMA polymer proposed by the company Neste Chemical under the reference NRT 354. It reacts with an isopropenyl compound of formula

proposed by the firm American Cyanamid under the name TMI, to give the functional polymer of general form:

In the third example, the functional groups are of the acrylate type. The initial polymer is obtained from ethylene monomer and of the order of 16% by weight of vinyl alcohol. It may be the EVOH polymer proposed by Bayer under the reference Levasint S-31. It reacts with an acrylic acid compound to give the functional polymer of the general formula:

In all cases, the operating conditions of the different reactions implemented are determined in order to obtain a polymer functional that contains an adequate proportion of groupings functional, to obtain the desired result, namely to obtain, under the action of electrons, a localized increase in melting temperature due to the self-crosslinking of said polymer functional and which moreover meets the conditions imposed by application to the fusible interlining of the support on which the Functional polymer dots are deposited.

Claims (5)

A method of manufacturing a fusible interlining, wherein is deposited on the face of a stabilizer support, selected from the textile supports and nonwovens, points of thermofusible polymer and subject the back side of the support of interlayer for electron bombardment, characterized in that the hot-melt polymer dots are based on at least one functional polymer having functional groups capable of reacting with free radicals under the action of an electron bombardment and / or same generators of free radicals under the action of electron bombardment, and what is regulated the depth of penetration of the electrons in the polymer points to obtain a self-crosslinking of said functional polymer on a limited thickness e with respect to the average thickness E of the polymer points. Thermofusible polymer for fusible interlining, specially designed for the implementation of the method of claim 1 characterized in that it comprises functional groups generating free radicals or capable of reacting with free radicals generated under the action of a bombardment electronic. Polymer according to Claim 2, characterized in that the functional groups contain functions with ethylenic unsaturation, for example of the acrylate, methacrylate, allyl, acrylamide, vinylether, styrene, maleic or fumaric type. Polymer according to Claim 2, characterized in that the functional groups comprise labile entities whose binding energies are lower than the usual carbon-carbon or carbon-hydrogen bonds. Polymer according to Claim 4, characterized in that the labile entity is a carbon-chlorine bond C-Cl or a thiol bond SH