EP1275769A1 - Process for surface treating textile fibres - Google Patents

Abstract

A process for treating fabric surfaces comprises dispersing microcapsules in an aqueous solution containing a dispersant and a crosslinkable fixer, impregnating the material by immersion, drying and exposing to UV radiation. The ratio of fixer to microcapsules is at most 0.5.

Description

The invention relates to a treatment method surface area of synthetic textile fibers and / or natural in order to fix microcapsules containing at least one active compound.

There are currently fabrics with properties thermoregulating whose objective is to limit the significant thermal variations in the human body, towards low or high temperatures.

Such properties give clothing, which include these fabrics, better comfort.

The thermoregulatory property of these fabrics can be obtained so far by a coating process superficial, on one or both surfaces fabric.

However, these thermoregulating fabrics have the disadvantage of being heavy and relatively rigid, and can only be used for the preparation of coats, jackets or combinations space.

There are still treated polymer fibers, having thermoregulatory properties, obtained by incorporating microcapsules inside each fiber. The microcapsules are an integral part of the base material, and are scattered throughout the structure (EP 0 306 202 B1).

Unfortunately, such fibers exhibit the disadvantage of not being able to understand large quantities of microcapsules in their internal structure.

Indeed, an increase in the amount of these microcapsules causes a significant decrease in initial characteristics of the fibers before their treatment. In addition, only synthetic fibers can be processed by the process described in this document.

Finally we still know a composition of fabric coating that includes microspheres wet (US 6,207,738). Microspheres containing this material are dispersed in an aqueous solution consisting of a surfactant, a dispersant and a antifoam. These microspheres are then dispersed in a polymer to form the composition of coating.

However, this American document discloses a deposit of coated microspheres, that is to say that the microspheres from 10 to 60 µm in average diameter are embedded in a binder, and the deposit forms a good layer distinct on the tissue surface.

Also, there remains the need to have fabric (or textile fibers) sufficiently flexible and light, to be easily worked and worn, and be easily adaptable to ready-to-wear sewing techniques, without however modifying their initial touch.

• disperser les microcapsules dans une solution aqueuse comprenant au moins un agent dispersant et au moins un agent de fixation réticulable, de façon à obtenir une dispersion de microcapsules enrobées d'agent de fixation,
• à imprégner les fibres de tissu une ou plusieurs fois par immersion dans la dispersion, puis à les sécher, et
• à soumettre les fibres de tissu séchées aux rayonnements U.V.

Le procédé se caractérise en ce que le rapport agent de fixation/microcapsules et au maximum égal à 0,5.
Selon l'invention, et contrairement à la composition de revêtement cité dans le brevet américain US 6,207,738 discuté précédemment les microcapsules ayant un diamètre maximal d'environ 10µm, sont liées de façon unitaire pour obtenir des tissus beaucoup plus légers que ceux issus de la composition de revêtement divulguée dans ce brevet américain.The subject of the invention is therefore a method of surface treatment of tissue fibers with a view to attaching microcapsules comprising at least one active principle therein.
This process consists of:

• dispersing the microcapsules in an aqueous solution comprising at least one dispersing agent and at least one crosslinkable fixing agent, so as to obtain a dispersion of microcapsules coated with fixing agent,
• impregnating the fabric fibers one or more times by immersion in the dispersion, then drying them, and
• subjecting the dried fabric fibers to UV radiation

The method is characterized in that the fixing agent / microcapsule ratio is at most equal to 0.5.
According to the invention, and unlike the coating composition cited in American patent US Pat. No. 6,207,738 previously discussed, the microcapsules having a maximum diameter of approximately 10 μm are linked in a unitary manner to obtain fabrics that are much lighter than those from the composition. coating disclosed in this US patent.

The invention has the advantage of obtaining relatively light fabrics (or textile fibers) exhibiting good resistance to wear due friction and / or successive washing cycles, insofar as the microcapsules are fixed by chemical bond to the surface of textile fibers.

Indeed, the polymer fibers from the process according to the invention are not coated with a binder incorporating the microcapsules.

Another advantage of the process of the invention is that allow unitary fixation of each microcapsule, thus limiting the mass of binder on the surface of the fibers, and therefore allowing maximum conservation of the initial characteristics of the tissue, such as touch, flexibility, lightness.

The method according to the invention makes it possible to reduce increase in the total mass of fibers treated corresponding to around 15%, while providing these fibers active storage and return of thermal energy.

Another object of the invention is a microcapsule intended for the implementation of the above process, and having a number average size less than 1 .mu.m.

Such microcapsules can have the function to store and then release thermal energy, at a temperature ranging from about 10 to 45 ° C, thanks to the presence, for example of chemical compounds present in their internal structure basically made up of oil comprising from 16 to 22 carbon atoms.

The invention also relates to a fiber of textile capable of being obtained by the process described above, which includes microcapsules spread evenly or not over the whole of the surface of the fiber, said fibers thus treated having thermoregulatory properties.

Finally the last object of the invention is a use of microcapsules as defined previously which include at least one active compound in order to provide thermoregulatory properties textile fibers comprising said fibers microcapsules on their surfaces.

• pour leur contenu : d'un polyéthylèneglycol, d'une huile hydrocarbure aliphatique ayant de 16 à 22 atomes de carbone, ou de leur mélange
• pour leur contenant : d'un polymère (polycarbonate, polystyrène, polyester insaturé) ou d'autres polymères compatibles vis-à-vis du contenant, ou de leur mélange.

The microcapsules are waterproof, and are made up of:

• for their content: of a polyethylene glycol, of an aliphatic hydrocarbon oil having from 16 to 22 carbon atoms, or of their mixture
• for their container: a polymer (polycarbonate, polystyrene, unsaturated polyester) or other polymers compatible with the container, or their mixture.

After treatment with UV radiation, the textile fibers, which can be synthetic or natural, woven or not, may be subject to temperature rise to around 120 ° C for one duration of up to 2 hours.

UV radiation can be carried out under inert atmosphere. It can also be done under air provided that the crosslinkable fixing agent does not include dissolved oxygen.

Submission to UV radiation can be carried out for a period ranging from a few seconds up to 3 minutes, and in the presence of at least one photoinitiator (benzophenone) and optionally coupled to another thermal initiator which is activated under the effect temperature, such as methyl ethyl ketone peroxide.
Such a catalytic system can also comprise other photoinitiators present in small percentage (about 0.01 to 1%) such as alphahydroxyketones.
The presence of photoinitiator makes it possible to initiate the fixation of the microcapsules on the surface of the textile fibers, by radical copolymerization of the fixing agent (also called bridging agent) present between each microcapsule and the surface of the textile fiber. The bridging agent coats each microcapsule.

The microcapsules are fixed to the surface of the polymer fibers by grafting. The dispersing agent can be chosen from surfactants anionics, nonionic surfactants, amphoteric surfactants, dispersing agents or wetting agents or their mixture, and more particularly among sulfonated paraffins (such as sodium dodecyl sulfate), or a mixture thereof.

The fixing agent can be chosen from vinyl compounds, acrylic compounds or their mixture, and more particularly among the acrylates aliphatics, urethanes acrylates, ethers acrylates, and their mixture.

According to the use made of the fiber treated by the process of the invention, one can use microcapsules, most of which (around 80%) has an average diameter of around 0.5µm. In addition, the amount of binder can be increased up to 50% by mass relative to the quantity of microcapsules of so as to allow, on the one hand a correct coating of microcapsules and, on the other hand, to increase the holding of the tissue fiber against abrasion.

Furthermore, to decrease the time of preparation of the binder / microsphere mixture, the ratio mass of this mixture can be around 0.4 when using an alcohol having 3 to 5 atoms of carbon.

Finally in order to obtain a unitary coating of each microcapsule by the binding agent, we can use chemical compounds that have both a role binding agent and surfactant, such as acrylates grafted with or without additional addition of others surfactants.

The invention will now be described using examples which follow and which are given only for illustration.

Example 1 : a) Preparation and deposition of microcapsules

• pour le contenant : polycarbonate de bisphénol A
• pour le contenu : eicosane

Le bain de trempage se présente de la façon suivante :

Les microcapsules sont dispersées dans une solution aqueuse contenant 2g/l de dodécylsulfate de sodium (SDS) et 1g/l de Triton 100 (marque déposée)(agent dispersant) chimiquement compatible au diacrylate de dipropylèneglycol (DPGDA)(agent de fixation) de façon à ce que le ou les agents de fixation se retrouvent sur la surface de la microcapsule. Ainsi chaque microcapsule est enrobée de façon unitaire et homogène par l'agent de pontage ainsi que par son système catalytique constitué de benzophénone dissous dans l'acrylate.

La solution de dispersion comprend 30g/l de microcapsules thermorégulantes dans le mélange eau/tensioactifs.

Les microcapsules sont appliquées sur la surface de fibres de textiles en plusieurs passages, et dans le cas présent 4 passages, par foulardage (opération qui consiste à imprégner le tissu dans la solution de dispersion, puis à le faire passer entre deux rouleaux exprimeurs ayant pour rôle de contrôler le pourcentage de dépôt de microcapsules sur le tissu).

The microcapsules are deposited on synthetic textile fibers by liquid or by dipping. To apply microcapsules with thermoregulatory properties, the latter must have an average size of the order of a micron, said size not exceeding half the average diameter of the fibers so as not to change the initial feel of the fabric.
The microcapsules are sealed, and consist of:

• for container: bisphenol A polycarbonate
• for content: eicosane

The soaking bath is as follows:

The microcapsules are dispersed in an aqueous solution containing 2 g / l of sodium dodecyl sulphate (SDS) and 1 g / l of Triton 100 (registered trademark) (dispersing agent) chemically compatible with dipropylene glycol diacrylate (DPGDA) so that the fixing agent or agents are found on the surface of the microcapsule. Thus each microcapsule is coated in a unitary and homogeneous manner by the bridging agent as well as by its catalytic system consisting of benzophenone dissolved in the acrylate.

The dispersion solution comprises 30 g / l of thermoregulating microcapsules in the water / surfactants mixture.

The microcapsules are applied to the surface of textile fibers in several passes, and in this case 4 passes, by padding (operation which consists in impregnating the fabric in the dispersion solution, then passing it between two expressing rollers having for role of controlling the percentage of microcapsule deposition on the tissue).

b) Attachment of microcapsules

The whole consisting of tissue and microcapsules is dried to remove water from the solution dispersion.

The fabric is subjected to UV radiation under nitrogen for 2 minutes.

The fabric of this example has active properties for storing and restoring thermal energy, the thermal power of which can reach approximately 3 kilojoules / m ² at around 37 ° C.

Example 2

• pour le contenant : polycarbonate de bisphénol A
• pour le contenu : octadécane

We use the same operating mode as that of Example 1. But here the microcapsules are made up:

• for container: bisphenol A polycarbonate
• for content: octadecane

The aqueous solution includes the same agents dispersants and an aromatic acryl urethane (UAA) like fixing agent.

The catalytic system activating binding of the bridging agent is a 50/50 mixture alphahydroxyketone and benzophenone.

The fabric used is a natural fiber, such as wool.

The fabric from this example has power thermal of about 2.5 kJ / m2 at around 28 ° C.

Example 3 :

• pour le contenant : polycarbonate (40% du poids total des microcapsules)
• pour le contenu : éicosane (60% du poids total des microcapsules)

sont imprégnées par un mélange hexanol/DPGDA comprenant le système catalytique (benzophénone 50% et alphahydroxycétone 50%) jusqu'à l'obtention d'un mouillage correct des microcapsules. On ajoute de l'eau de dilution comprenant 1% de tensioactif (polyvinyl alcool) sous agitation.In this example to facilitate the preparation time of the binding agent / microcpsule mixture and moreover to obtain the desired dispersion of said microcapsules, the latter are made up:

• for the container: polycarbonate (40% of the total weight of the microcapsules)
• for the content: eicosan (60% of the total weight of the microcapsules)

are impregnated with a hexanol / DPGDA mixture comprising the catalytic system (benzophenone 50% and alphahydroxyketone 50%) until a correct wetting of the microcapsules is obtained. Dilution water comprising 1% surfactant (polyvinyl alcohol) is added with stirring.

The mass ratio of binding agent / microcapsules is about 0.5.

• microcapsules : 15%
• DPGDA : 7 ,5%
• Hexanol : 30%
• Eau : 47,5%

On peut toutefois remplacer une part de DPGDA par une part d'acrylate greffé à une chaíne hydrocarbonée servant également de tensioactif.
L'application de la solution sur les fibres de tissus se fait au foulard suivi d'un brossage des surfaces de tissus pour homogénéiser le dépôt
Un séchage par air chaud permet ensuite d'éliminer l'eau de dilution et l'hexanol.
La réticulation (ou fixation des microsphères) est effectuée sous air à l'aide d'une lampe à vapeur de mercure à une longueur d'onde de 254nm avec un puissance de 700mW/cm² sur un convoyeur à la vitesse de 30m/min.
Le tissu de cet exemple présente une activité thermique de 3,5kJ/m². Cette dernière peut varier en fonction de la pression des rouleau du foulard appliquée lors de l'étape d'imprégnation.The solution includes approximately:

• microcapsules: 15%
• DPGDA: 7.5%
• Hexanol: 30%
• Water: 47.5%

One can however replace a part of DPGDA by a part of acrylate grafted to a hydrocarbon chain also serving as surfactant.
The solution is applied to the fabric fibers using a scarf followed by brushing the fabric surfaces to homogenize the deposit
Hot air drying then removes the dilution water and hexanol.
The crosslinking (or fixing of the microspheres) is carried out in air using a mercury vapor lamp at a wavelength of 254nm with a power of 700mW / cm ² on a conveyor at a speed of 30m / min .
The fabric of this example has a thermal activity of 3.5 kJ / m ² . The latter can vary depending on the pressure of the scarf rollers applied during the impregnation step.

Claims (12)

Method for surface treatment of tissue fibers with a view to attaching microcapsules comprising at least one active principle, comprising: dispersing the microcapsules in an aqueous solution comprising at least one dispersing agent and at least one crosslinkable fixing agent, so as to obtain a dispersion of microcapsules coated with fixing agent, impregnating the fabric fibers one or more times by immersion in the dispersion, then drying them, and subjecting the dried fabric fibers to UV radiation characterized in that the fixing agent / microcapsule ratio is at most equal to 0.5. Method according to claim 1, characterized in that the submission to UV radiation is carried out under an inert atmosphere, or else in the presence of air and in this case with a fixing agent not comprising dissolved oxygen. Method according to claim 1, or claim 3, characterized in that the submission to UV radiation takes place for a period ranging from a few seconds to 3 minutes. Method according to claim 1 or claim 3, characterized in that the submission to UV radiation is carried out in the presence of at least one photoinitiator. Method according to claim 1, characterized in that the dispersing agent is chosen from ionic surfactants, amphoteric surfactants, nonionic surfactants, wetting agents dispersing agents or mixtures thereof. Method according to claim 1, characterized in that the fixing agent is chosen from vinyl compounds, acrylic compounds or a mixture thereof. Method according to one of claims 1 or 5, characterized in that the dispersing agent is chosen from sulfonate paraffins. Method according to one of claims 1 or 6, characterized in that the fixing agent is chosen from aliphatic acrylates, urethane acrylates, ethers acrylates and their mixture. Process according to Claim 1, characterized in that the active principle of the microcapsules is chosen from an aliphatic hydrocarbon oil having from 16 to 22 carbon atoms, a polyethylene glycol or a mixture thereof. Microcapsule intended for the implementation of the method according to one of claims 1 to 8, characterized in that it has a number average size of less than 1 µm. Use of microcapsules according to the claim 10 comprising at least one active compound to provide thermoregulatory properties to tissue fibers comprising said microcapsules on their surfaces. Fabric fiber capable of being obtained according to the process defined according to one of claims 1 to 9, characterized in that it comprises microcapsules disposed uniformly or not over its entire surface, said fiber having thermoregulatory properties .