FR2722803A1 - INSULATING MATTRESS MADE OF FIBROUS MATERIAL IMPREGNATED WITH AN INSULATING PRODUCT - Google Patents

Abstract

The subject of the invention is an insulating mattress made of a fibrous material impregnated with an insulating product. The insulating product is sprayed in the form of a mist of fine droplets, so as to ensure good penetration into the mattress while facilitating its drying.

Description

I The invention relates to an insulating mattress and a method for

  manufacture an insulating mattress and in particular for manufacturing an impregnated insulating mattress. The expression "insulating mat" covers all insulating materials which have a defined shape - unlike a loose product

  disaggregated, liquids or the like.

  Such insulating blankets (insulating panels) based on mineral fibers have been known for many years in the state of the art.

  technical and have proven themselves in construction.

  Recently, we also find more and more insulating materials based on plant or animal fibers. The problems then relate to their behavior in protection against fire as well as their biological resistance. Insulation products made of the aforementioned fibrous materials must therefore be provided with a corresponding impregnation, insofar as they must meet specific requirements concerning the fire protection behavior, respectively concerning the

  resistance to biological attack, for example by insects.

  The mobility of insects requires that the impregnating agent be distributed as regularly as possible in the volume of the product. For this, it is known to spray the corresponding insulating mat with the impregnating agent or to prepare the impregnating agent to obtain a cellular product and apply it to the insulating mat. Due to the low penetration tendency, these techniques can only be used on very thin mattresses; when we have thicker mattresses, we

  practically only impregnates in the area of the surface which -

  as shown - is insufficient. At the interfaces or at the cutting points (during further processing), gaps appear

"additional impregnation.

  In principle, impregnation in the mass, for example by immersion of an insulating mattress in an impregnation bath would be possible to achieve. Such a process would however be very expensive and the insulating blanket would then have to be dried again, at the cost of considerable energy expenditure. Impregnation in the desired mass can in principle also be obtained by treating the flakes (for example from cotton, linen or sheep's wool) before the carding process (therefore before the formation of the primary mattress). The essential drawback encountered in this process is that the insulating material is exposed during the carding process to a significant mechanical stress. Tests have shown that by doing this, a new mechanical separation, of up to%, of the impregnating agent is obtained. The result is an insulating mattress with totally insufficient impregnation. Simultaneously the

  installations are soiled by the impregnating agent who has separated.

  This is why the invention aims to provide an insulating mattress which has a distribution of the impregnating agent giving the product, over its entire volume, more or less equal properties and which can

  be made using as simple a process as possible.

  The invention then has as a basis the following knowledge: starting from a known process, in which fibers (flakes) are first prepared in a primary mattress and then reprocessed by shaping the primary mattress into a secondary mattress, I ' The invention now provides for subjecting the primary mattress to an impregnation treatment before shaping into a secondary mattress, the impregnating agent preferably being sprayed in liquid form, like a mist, on at least one face of the primary mattress. A variant application of the application agent is distinguished by the fact that a cellular impregnation product is applied to the primary mattress and thus also to a depth

  determined inside the primary mattress.

  The process by which the impregnating agent is applied to the primary mattress then constitutes a completely essential idea of the invention. The previous spraying methods, with the aid of which for example a binder is sprayed on fibers, have a relatively large droplet diameter. A corresponding impregnation process should lead to the primary mattress being only partially impregnated. The appended FIG. 1 represents in a highly diagrammatic manner a surface of fiber on which are arranged - at great distance from each other - individual impregnation droplets, which give after a

  drying process a corresponding impregnation coating.

  The invention, on the other hand, provides for spraying the impregnation product in liquid form, in the form of a mist, and for treating the impregnating agent therefore in the form of an aerosol. In this way, very fine liquid particles are guided in a corresponding carrier gas (generally air) on the primary mattress and the mist can then be deposited not only on the neighboring face of the spray device of the primary mattress, but also, in a particularly advantageous manner, in the “loose and porous structure” of the primary mattress and spreading there by crosslinking on the individual fibers. A very important aspect is the fact that the different particles of liquid are much smaller than what is obtained with a conventional spraying process, as expressed by the concept of "mist", respectively. "aerosol", so that the final effect is to have small very fine droplets of liquid, directly next to each other, depositing on the corresponding surfaces of the fibers, as shown under a very form

shown schematically in Figure 2.

  Although individual liquid particles have been sprayed, the final effect - after drying - is a roughly closed impregnation coating which is correspondingly superior, also in terms of its effectiveness to the process. according to the state of the

technical.

  The particles of liquid which are much smaller and are applied by the spray mist to the primary mattress have the additional advantage that they can be dried much more quickly, so that the problems arising during following treatment. This applies in particular to the reprocessing of the primary mattress into a secondary mattress. If a pendulum member is used here, for example, as is known from European patent 0 528 348 A1, the primary mattress must then be more or less dried, since otherwise it would adhere to the surfaces of the conveyor belts.

the pendulum organ.

  The surface tension of the aerosol can also be adjusted so that coating sections with larger areas are established on the individual fibers, as shown schematically in Figure 3. A similar coating image is also obtained when the impregnating agent is applied in the form of a foam or a cellular product. This can be done under pressure but

  also under vacuum (from below).

  By means of the new process described, one can either completely give up having a separate drying station (because air drying of the primary mattress on the way to the continuation of the treatment in secondary mattress is already sufficient) or have a much shorter and much simpler drying station, owing to the fact that particles of

much smaller liquid.

  According to one embodiment, it is provided, correspondingly, that the primary mattress is dried after treatment.

  impregnation, but before further treatment.

  The rest of the treatment can then be carried out by a pendulum member, as described in detail in the European patent.

0528 348 A1.

  Preferably, the impregnation treatment is carried out for a primary mattress (non-woven veil) with a surface weight of between 30 and 90 g / m2. Tests have shown that, when mattresses having such a specific weight were had, one could have an impregnation in the practically complete mass of the primary mattress and, thus also, of the

  insulating mattress made from the primary mattress.

  Due to the fact that the impregnating agent is applied from the outside, a concentration of the coating agent must be obtained which is observed while observing in different planes (perpendicular to the spraying direction), increasing as one moves in the spray direction. This leads to the result of an insulating mattress consisting of a secondary mattress formed by multiple folding of a primary mattress and for which the primary fiber mattress has at least on one side a coating.

  an impregnating agent as is the subject of claim 1.

  The term "on one side" means that the primary mattress takes on, after the secondary mattress treatment and subsequent compaction, a "flat shape", in which, in accordance with the explanations

  given above, the concentration of impregnating agent is maximum.

  The insulating mat, constructed from the different layers (primary mat) is impregnated by the technique of the process described, continuously, so that - depending on the impregnating agent - it is also possible to obtain protection classes against fire that meet requirements

  high in terms of insect resistance.

  Of course, the primary mattress can also be sprayed on both sides so that the concentration of the impregnating agent can be increased above all. Here again, however, the concentration in relation to the volume of impregnating agent for the primary mattress always decreases from the outside to the inside and, in any case, there is in the median zone a certain over-concentration in the measure or impregnation

is done on both sides.

  If the impregnating agent is sprayed as a mist, the different impregnation phases (after drying) - as shown schematically in Figure 2 - can be very small and, according to one embodiment, have an area less than 0.1 mm2, preferably less than 0.01 mm2. The corresponding droplet diameter should correspondingly be less than the average diameter of the afferent fibers. The high concentration of liquid particles in the mist leads to the result that the spacing between individual liquid droplets, respectively after drying, the impregnation phases are very small, or that smaller coating phases are obtained, consistent, made up of individual droplets, and which, when viewed from the outside, provides a coating

  of almost continuous impregnation.

  According to the invention, the average droplet diameter is at least 10 times less than what is obtained with the process

  comparable, as discussed above.

  By modifying the surface tension of the impregnating agent in the form of an aerosol, the various fibers can also be coated on the surface, as shown. The intended effect

therefore remains unchanged.

  Tests have shown that, by the described modification of the type of spraying, the quantity of impregnating agent can be reduced until decreasing by approximately 90% compared to the known impregnation method, while obtaining the same results. Spray devices with which liquids can be sprayed as a mist (these are liquid impregnating agents) are known in the art, however, they are intended for other applications, for example example for painting or for enameling ceramic parts. The sprayed liquid is then broken down in the spray head, giving very fine droplets which are then deposited on the fibers and lead to

  this place to a kind of "dense carpet" (what is called the process "air-

brush ").

Claims (10)

  1. Insulating mattress, consisting of a secondary fiber mattress formed by multiple folding of a primary fiber mattress, characterized in that the primary fiber mattress has at least on one side a coating with an impregnating agent. 2. Insulating mattress according to claim 1, in which the covering consists of intimately contiguous but individualized sections, of a surface less than 0.1 mm2.   3. Insulating mattress according to claim 1, in which the coating is   consisting of flat sections on the individual fibers.   4. Insulating mattress according to one of claims 1 to 3, in which the   primary mattress has a coating on both sides.   5. Insulating mattress according to one of claims 1 to 4, in which the   concentration, expressed in volume, of impregnating agent for the mattress   primary is decreasing going from outside to inside.   6. Insulating mattress according to one of claims 1 to 5, in which   the impregnating agent is a protective agent against fire or insects.   7. Insulating mattress according to one of claims 1 to 6, based on fibers   animal or plant, or a mixture thereof.   8. A method of manufacturing an insulating mattress, in which fibers are first prepared to constitute a primary mattress and then are reprocessed by shaping the primary mattress to give a secondary mattress and impregnated during manufacture, characterized in that the mattress primer is subjected before shaping into a secondary mattress to an impregnation treatment, the impregnating agent being in the form of a liquid, in spray mist on at least one face of the primary mattress or else in the form of alveolar products applied to, and in, the primary mattress. 9. The method of claim 8, wherein the primary mattress sprayed with the impregnating agent is dried before the continuation of the secondary mattress treatment.   10. The method of claim 8 or 9, wherein the primary mattress is transformed into a secondary mattress, by means of a pendulum member.   i11. Method according to one of claims 8 to 10, wherein   The alveolar impregnation is carried out under pressure or under vacuum.