FR2514043A1 - METHOD FOR REINFORCING THE SURFACE OF FIBER-FORMED OBJECTS AND REINFORCED OBJECTS - Google Patents

Abstract

THE INVENTION CONCERNS THE STRENGTHENING OF POROUS BODIES. IT RELATES TO THE REINFORCEMENT OF THE SURFACE OF POROUS BODIES IN THE FORM OF MINERAL FIBERS. AFTER DRYING, A LIQUID BINDING COMPOSITION WHICH CONTAINS A SOLVENT AND WHICH HAS BEEN APPLIED TO THE SURFACE OF THE BODIES, SHAPES A FILM ON FIBERS 1 AND THEIR INTERSECTIONS 2, BUT LEAVES OPEN PORES IN INTERMEDIATE SPACES 3. THE SURFACE IS HARD AND RESISTANT AND THE BODIES ARE HOWEVER POROUS AND PERMEABLE TO WATER VAPOR. APPLICATION TO EXTERNAL COVERINGS OF HOUSES.

Description

The present invention relates to reinforcing

  the surface of porous bodies or plates, for example slabs or plates of mineral wool, and

than such reinforced objects.

  It is known, in particular according to the Danish patent No. 97 863, the strengthening of the mineral wool plates containing glass fibers, rock or slag, by application of a solution of a binder of

  The types of binders used have

  while tending to fill the spaces separating the fibers of the porous plates so that these plates become impervious to moisture and air The sound insulation and absorption properties of these plates are thus considerably reduced. The filling of the pores is harmful when the porous plates are used as external wall and ceiling cladding, since such plates must at least be

  they allow the diffusion of moisture.

  The invention overcomes these disadvantages, and relates to a surface reinforcement of porous bodies or plates containing fibers and a cured binder, for example mineral fibers and a hardened phenolic resin, forming an elastic network to some extent with spaces which extend between the fibers, this reinforcement being such that, in a surface layer of the porous body, a binder composition containing a solvent is introduced, this composition, when it has dried by evaporation of the solvent, forming a film on the individual fibers or the individual bundles of fibers and at their intersections in the porous body so that the interspaces are

free and open.

  Drying and optimum properties are achieved.

  when the binder composition contains latex,

  and when the solvent is of an aromatic type.

  The reinforced porous bodies according to the invention are suitable in the form of an external coating and a

  combined insulation for homes Such coatings

  may have a hard surface, may be

  They are suitable for moisture diffusion and can have high impact resistance and tensile strength. In addition, the bodies are inexpensive to manufacture and mount. The bodies according to the invention can be mounted on existing coatings by glue or by mechanical devices One of their surfaces is hard and does not require other finishes However, if it takes another color or another structure superficial, the hard surface allows the application of topcoat without particular precautions because the surface of the body is suitable for the application of the usual paints for the walls

or plaster.

  An outer covering and an insulation can be mounted using the bodies according to the invention, at half the price of about a usual external insulation, for example as described in the European patent

  In addition, the weight of the coating according to the invention

  is significantly lower than the known systems

coating.

  Other features and benefits of

  the invention will emerge more clearly from the description which

  will follow, with reference to the accompanying drawings in which Figure 1 shows schematically fibers with a binder but without the binder composition; Figure 2 shows the fibers of Figure 1 with the binder solution; and Figure 3 shows the same fibers after

drying the composition.

  The drawings represent fibers in

  a plan, but in fact, the fibers form a triple network

  dimensional. Figure 1 shows schematically and in enlarged form some fibers 1 in a piece of a porous mineral wool plate. The fibers are glued to each other at their intersections 2 by a binding agent such as a hardened phenolic resin,

  intermediate spaces 3 being delimited between the fibers.

  Figure 2 shows the same section as Figure 1 but after application of a liquid solution of a binder composition as indicated by the points. The liquid composition fills the spaces 3 The liquid binder contains a volatile solvent When this solvent evaporates from the binder composition, a shrinkage appears around the fibers 1 as indicated schematigueroent in Figure 3 and a continuous film 4 forms on the fibers, the intermediate spaces 3 remaining open and allowing free passage so that the mineral wool plate becomes permeable to air and water vapor A physical drying process with a significant reduction in volume takes place The binder composition dried 4 strengthens the fibers and prevents the jamming and fracturing of the fibers In addition, the intersections have a resistance

  increased so that the tensile strength is increased.

  Compressive strength, tensile strength

  stiffness increases, in addition to the superficial hardening of

  sky, without the porosity changes noticeably Some of the fibers can be very close together in bundles

  The binding composition then surrounds the

  fiber bundles The liquid composition applied to the

  porous plate can be an emulsion or a solution.

  The binder can be for example a latex, polyvinyl acetate, a combination of polyvinyl chloride and vinyl ether or copolymers such as

  butadiene-styrene type and acrylic-vinyltoluene ester.

  The binder may be dissolved in a solvent, for example an aliphatic solvent, an aromatic solvent, an ester or a ketone. The aromatic solvents may be

xylene or toluene.

  Several substances can be added to the binding composition so that they improve the properties of the reinforced product. These substances can be added so that they improve the properties of the reinforced product. These substances can be pigments, fire-retardants or plasticizers.

  chlorinated paraffins are used as

  tifiers, cracking during drying is minimal.

  The liquid binder composition can be applied by conventional varnishing or dipping equipment

  in a container using the binding composition

  Depending on the amount of solvent in the composition, the speed and depth of penetration and porosity can be adjusted. The liquid binder can penetrate the entire thickness of the plate as needed.

  The binder may contain about 100% volatile solvent.

  The reinforced mineral wool plate can be made from mineral wool slabs having different thicknesses or densities and can be used in other applications than

those we have mentioned.

  The invention is not limited to the reinforcement of mineral wool but can be used with other materials having a fibrous structure, such as materials formed of cellulose fibers or

wood wool.

  In external housing coatings, a binder composition application which is normally 5 liters per square meter is sufficient and corresponds to

  at a penetration depth of 10 mm.

Claims (4)

  A method of reinforcing the surface of porous plates or porous bodies containing fibers and a hardened binding agent, for example mineral fibers and a hardened phenolic resin, forming an elastic network to a certain extent with spaces emerging between   fibers, characterized in that it comprises the introduc-   in a surface layer of the porous body, a binder composition containing a solvent, this composition, after drying by evaporation of the solvent, forming a film (4) on the individual fibers (1) or the individual bundles of fibers and their intersections in the porous body so that the interspaces are open and opening.   Process according to Claim 1, characterized   in that the binder composition is a latex.   3 Process according to claim 1, characterized   in that the solvent is an aromatic solvent.   4 object in the form of plates or porous bodies,   characterized in that it comprises a reinforcement of   face made by implementing a method according to one   any of claims 1 to 3.