GB2173151A

GB2173151A - Automobile floor overlay

Info

Publication number: GB2173151A
Application number: GB08607057A
Authority: GB
Inventors: Hans Rumenapf
Original assignee: Ideal Automotive GmbH
Current assignee: Ideal Automotive GmbH
Priority date: 1985-03-23
Filing date: 1986-03-21
Publication date: 1986-10-08
Also published as: IT1189078B; DE3510722A1; FR2579235B3; GB8607057D0; ES296521Y; IT8619831A1; ES296521U; FR2579235A1; IT8619831A0; GB2173151B; DE3510722C2

Abstract

An automobile floor overlay consists of a carpet (4) and an acoustically insulating foam mat 1 having a closed skin (3) facing the carpet, there being a foam layer (7) formed from a prepolymer provided between the carpet and the mat, the foam encompassing zones 6 of the carpet and being firmly bonded to the closed skin. <IMAGE>

Description

SPECIFICATION Automobile floor overlay This invention relates to an automobile floor overlay, consisting of a carpet and a foam acoustically insulating mat, which is bonded to the underside of the carpet and possesses, at least on the face towards the carpet, a closed skin.

Automobile floor coverings of this type are known. The carpet, in particular pile carpet, makes the interior of the vehicle comfortable. The acoustically insulating mat usually consists of a polyurethane foam. It reduces noise transmission from the floor plating to the interior. The insulating mat is adapted, on its underside, to ribs, bars or similar deformations of the automobile plating. On its upper face, towards the carpet, it is substantially flat and possesses a closed skin. The skin is not formed of a separate foil, but is produced during foaming of the acoustically insulating mat in a mould. By the skin, the upper face of the acoustically insulating mat is water-repellant, so that water penetrating through the carpet to the mat cannot penetrate into the latter.Should water or moisture penetrate into the acoustically insulating mat, then the water would be stored there, which would be very unpleasant, because on the one hand the water absorption capacity of the acoustically insulating mat is large and, on the other hand, the facilities for drying out are bad.

In known automobile floor coverings, the carpet is firmly bonded to the acoustically insulating mat by means of a solvent-containing adhesive. As the adhesive hardens, solvent vapours escape into the environment. This is undesirable. To achieve adequate bonding, approximately 200 p/m2 are necessary. Within the framework of the weight reduction aimed at in automobile construction, this weight is not inconsiderable. The adhesive forms, between the undersides of the piles and the skin, only a glued connection. It is not impossible that the adhesive may loosen in the course of time under the effects of heat and/or humidity. If the solvent of the adhesive has attacked the skin and the bonded connection becomes loosened, then moisture can penetrate into the foam acoustically insulating mat.

This too is undesirable.

In DE-PS 1 032 714, a method of making elastic laminated fabrics of continuous porosity is described. In that Patent, a polymerisable, gas-evolving synthetic resin mixture is spread thinly onto one of the surfaces of the layers to be bonded together, for example of textiles and foams. The other layer is laid over this and the layers are pressed together during the gas evolution and polyermisation of the synthetic resin mixture. In order to obtain a product porous throughout, a solvent is added to the synthetic resin mixture. By this the result is achieved that a separating foam layer does not form, but a lattice-like or net-like layer, and therefore a continuously porous connection between the two starting materials.For producing an automobile floor overlay of the initially named type, this process is not suitable, because an overlay should not be continuously porous and the use of a solvent is undesirable.

In DE-PS 1 669 786, a method of making embossed, foil-like laminated materials is described.

Onto one of the covering layers of the polyurethane foam sheet, an anhydrous film of a foamable polyurethane material is to be applied and made to foam by adding moisture. The covering layers are pressed through this film and glued to one another, so that the spaces situated between the pressed-through points of the covering layers are filled with foam and the covering layers are bonded in these regions by the foam. The entire space between the covering layers is porous. With this method, an acoustically insulating mat of the aforementioned type could be produced, closed on both faces with foils and adapted to the profile of the bottom plating. However, automobile floor overlays of the initially named type cannot be produced by this method, because the prefabricated acoustically insulating mat must not be modified by bonding to the carpet.

The task underlying the present invention is, in an automobile floor overlay of the initially named type, to bond the carpet to the acoustically insulating mat without a solvent-containing adhesive being used for this purpose and without a moisture-permeable connection between the carpet and the interior of the acoustically insulating mat being produced.

The aforementioned task is achieved in an automobile floor overlay of the initially named type in that, between the carpet and the closed skin, a foam layer foamed from a prepolymer is provided, and in that the foam layer on the one hand encompasses the lower zones, especially piles, of the carpet and on the other hand has bonded to the closed skin.

The prepolymer contains no solvent. Accordingly, no solvent vapours are produced during foaming. By means of the foam layer, the carpet is securely anchored to the acoustically insulating mat. A favourable feature also is that the foam layer does not swell under the effects of moisture and also does not dissolve or become loosened.

The vapourising problems existing with aqueous adhesives also do not occur.

The foam layer and the acoustically insulating mat have approximately the same elastic properties, so that bracing effects which could damage the skin do not occur. The foam layer strengthens and protects the closed skin, so that its water-tightness is assured over a long period. The bond is insensitive to moisture or thermal effects.

During foaming of the foam layer, the skin prevents the prepolymer from penetrating into the acoustically insulating mat. The foaming operation thus takes place towards the carpet, so that even with a very thin layer of prepolymer a secure embedding of the carpet is achieved. This also has the result that the weight of the foam layer is very low. It has been found that an application of prepolymer at a weight of 30 - 50 p/m2 is sufficient for a reliable, permanent bond.

If the acoustically insulating mat is of a polyure thane foam, then a polyurethane prepolymer is preferably used for the foam layer.

The foam layer, itself, consists of closed, stable mutually adhering foam bubbles. Between these, cavities exist, so that the foam layer itself is not water-repellant. Nevertheless, the foam layer reduces the water permeability from the carpet to the skin, because the water-repellant fibres of the carpet lie in the spaces between the bubbles of the foam layer.

A method of bonding the carpet and the acoustically insulating mat of the automobile floor overlay of the initially named type is characterised in that, onto the closed skin of the acoustically insulating mat, a prepolymer in a uniform layer and an activator are applied, and that the carpet is pressed onto the layer while the layer foams.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which: Figure 1 is a diagrammatic sectional view of tufted carpet automobile floor overlay, and Figure 2 is a diagrammatic sectional view of a needle fleece carpet automobile floor overlay.

The automobile floor overlay comprises a polyurethane foam acoustically insulating mat 1. This is profiled, on its underside, to the contour of an automobile floor plate and covered watertight with a foil 2. On its upper side, the mat 1 is substantially flat and closed watertight with a skin 3. The skin is produced during the manufacture of the acoustically insulating mat 1. It easily breaks if scratched.

It is considerably more sensitive than the foil 2.

After the skin 3 is broken, moisture can enter the interior of the mat 1.

The automobile floor overlay shown in Figure 1 possesses a tufted carpet 4, the loops 5 of which are conventionally fixed to a support lattice 6. The piles of the carpet lie flat. The carpet consists, for example, of fibres of polyamide, polyester, polyacrylic or polypropylene.

A polyurethane foam layer 7 is connected without adhesive to the skin 3. The foam layer 7 extends to above the support lattice 6 and thus encompasses the piles of the carpet 4. It fills the spaces between the loops 5. The loops 5 are thereby mechanically anchored in the foam layer 7.

The foam layer 7 has approximately the same elasticity as the acoustically insulating mat 1.

When the carpet 4 is trodden on, it accompanies the deformation of the acoustically insulating mat 1 without tearing. The foam layer 7 is intimately bonded to the skin 3. It thus reinforces the skin 3.

At the same time it protects the skin 3 from mechanical damage acting through the carpet 4.

The foam layer 7 consists of closed foam bubbles, so that its water absorption capacity is small.

The water absorption capacity is still further reduced by the cavities between the bubbles being largely occupied by the loops 5. If the carpet floor is wetted, the foam layer 7 hardly absorbs any water. In particular, however, no water penetrates into the acoustically insulating mat 1. The drying facilities are thus good. Drying usually takes place by the air stream existing in the interior of the vehicle. In no case is it necessary to remove and dry out the permanently laid floor overlay after wetting. Even after fairly long use, these properties do not change, because the foam layer 7 itself is insensitive to moisture effects and insensitive to the temperatures occurring in the automobile. Added to this is the fact that the foam layer 7 does not tear under the stresses to be expected, so that tearing of the skin 3 cannot take place.The support lattice 6 embedded in the foam layer 7 forms an additional reinforcement of the foam layer 7.

In practice the carpet 4 has a thickness of about 0.5 to 1 cm. The acoustically insulating mat 1, at least in its thicker zones, is thicker than the carpet 4. Its thickness varies, for example, between 1 and 3 cm. The foam layer 7 in practice has a thickness of about 0.2 to 1.5 mm.

The automobile floor overlay described is manufactured generally in the following way: Onto the skin 3 of the prefabricated acoustically insulating mat 1, a liquid polyurethane prepolymer is applied. This application can, for example, be by spraying. The quantity applied is 30 - 50 pit2. An activator, which initiates the foaming operation, is then applied. A corresponding carpet piece 4 is then immediately laid on the prepolymer and pressed on in a mould. The prepolymer now foams, possibly under the action of heat. In foaming, the prepolymer presses on one side onto the skin 3. The foam bubbles produced bond to this skin 3, without penetrating through it. Since the foam bubbles do not penetrate through the skin 3, a denser distribution of bubbles is produced in the immediate vicinity of the skin 3 than in the zones further from the skin 3.At the other side, the polyurethane foam layer 7 penetrates into the irregularities of the carpet back and fills these up. The bubbles evolved during foaming pass through the support lattice 6 and into the loops 5 or the spaces between them. After foaming, the carpet 4 is finally firmly bonded to the acoustically insulating mat 1.

The skin 3 is strengthened by the concentration of bubbles of the foam layer 7 in its vicinity. The piles of the carpet 4 are anchored in the foam layer 7.

The proportion of the weight of the foam layer 7 to the total weight of the automobile floor overlay is negligible.

In the example shown in Figure 2, a needle fleece carpet is provided, instead of the tufting carpet.

The description for Figure 1 applies here also. A woven carpet could also be firmly bonded in the same manner to the acoustically insulating mat 1.

It has been found that a secure carpet bond is achieved even if the acoustically insulating mat 1 is made from a polyethylene foam, which possesses a closed skin 3 and is intrinsically difficult to bond.

If the automobile floor overlay is not to be flat, but to be spacially deformed to fit the interior of the automobile, then for the bonding described, an appropriately premoulded acoustically insulating mat and an appropriately premoulded carpet piece are used as the starting materials.

Claims

1. An automobile floor overlay, consisting of a carpet and a foam acoustically insulating mat which is bonded to the underside of the carpet and which comprises, at least on the face towards the carpet, a closed skin, there being a foam layer foamed from a prepolymer provided between the carpet and the closed skin, and the foam layer encompassing lower zones of the carpet and being firmly bonded to the closed skin.

2. An automobile floor overlay according to claim 1, comprising a pile carpet, wherein the piles are anchored in the foam layer.

3. An automobile floor overlay according to claim 1 or 2, comprising a polyurethane or polyethylene foam acoustically insulating mat, wherein the foam layer is foamed from a polyurethane prepolymer.

4. An automobile floor overlay according to any one of the preceding claims, wherein the foam layer consists of closed foam bubbles connected to one another.

5. An automobile floor overlay according to any one of the preceding claims, wherein the weight of the foam layer is approximately 30 - 50 pit2.

6. An automobile floor overlay according to any one of the preceding claims, wherein the foam layer has a thickness of 0.2 mm to 1.5 mm.

7. An automobile floor overlay, substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawing.

8. A method of bonding a carpet and an acoustically insulating mat of an automobile floor overlay according to any one of the preceding claims, wherein a prepolymer in a uniform layer and an activator are applied onto the closed skin of the acoustically insulating mat and the carpet is pressed onto the layer while the layer foams.

9. A method of bonding a carpet and an acoustically insulating mat of an automobile floor overlay according to any one of claims 1 to 7, substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawing.