FR2510477A1 - COMPLEX COATINGS, PROCESS FOR OBTAINING SAME AND APPLICATIONS THEREOF, IN PARTICULAR IN THE FIELD OF INTERIOR TRIMS OF MOTOR VEHICLES - Google Patents

Abstract

The composite lining comprises a combination of a relatively thin decorative layer (2), preferably comprising a nonwoven, and a foam layer (4) made from synthetic copolymers which react on heating, in particular on application of high frequencies, such as polymers and copolymers of vinyl chloride and/or vinyl esters and/or vinyl ethers, optionally with addition of acrylates. The lining is bonded to an insulating and cushioning underlayer (3), which serves as a rigid supporting element after solidification, by heat-bonding of its foam side.

Description

 The present invention relates to complex coatings, their production process and their applications in particular in the field of interior trim of motor vehicles.

 The interior linings of motor vehicles generally consist of two elements made integral by bonding: a relatively thin decorative layer forming the surface of the lining and an insulating and padding underlay which serves as a rigid support after its consolidation and which, in the most of the cases are formed of a felt of recovery fibers bonded by a thermosetting and / or thermoplastic resin.

The production of these interior fittings, however, poses many problems. Indeed, the techniques and components currently used generally require working in two stages
We first thermoform the insulating and padding underlay to form the support shell; this underlay consists essentially of fiber waste, cotton or other, agglomerated with a resin such as a formophenolic resin
The thermoforming treatment causes a reaction and a diffusion of the resin and a migration of this resin as well as dyes from textile waste and other fatty products inside the material, but in particular towards the surface.

 The preformed shell is then glued by any means known per se and in particular by spraying with an appropriate resin, then the decor layer, generally a non-woven fabric, is applied by thermoforming / pressing. The glue can also be applied to the back of the decoration layer by spraying.

 It is essential to use for this purpose a nonwoven of sufficient weight / m2 in order to ensure the whole a correct appearance. Indeed, if the decorative layer does not have sufficient opacity, the dyes and other impurities present in the textile waste on the surface of the support shell will appear by transparency.

 Other problems also arise as a result of an excessive aptitude for hot creep of certain adhesives; it often happens that the glue, if it is deposited in excess on the shell, crosses the nonwoven under the effect of heat and pressure.

The lining then remains stuck to the mold or else becomes stained, which irreversibly damages it and, on the other hand, requires frequent cleaning of the molds, at the expense of productivity.

 The purpose of the present invention is to remedy the drawbacks mentioned above; the plaintiff has indeed, during numerous studies, been able to develop a complex coating whose originality consists in the association of a decorative layer, relatively thin and preferably chosen from nonwovens, with a layer of foam of synthetic copolymers which can be reacted hot, and in particular by high-frequency application, chosen from polymers and copolymers of chloride and / or vinyl esters and / or ethers optionally added with acrylic ester.

 Advantageously, the polymers and copolymers are chosen from polyvinyl chloride, ethylene vinyl acetate, vinyl acetate / maleate.

 According to one embodiment of the invention, the foam layer also comprises opacifying agents chosen from titanium oxide (in rutile or anatase form) and zinc oxide.

 Advantageously, the foam layer further comprises barrier agents chosen from products with a lamellar structure such as mica, lavermiculite, aluminum, bronze and copper, the latter three products being in the so-called "film-forming" form, c that is to say laminated in a dry / dry percentage between 10 and 50%.

 Alternatively, the barrier agents are chosen from silicon derivatives such as silica, sodium silicate and alumina silicate, according to a percentage between 40 and 120 X sec / sec.

 Advantageously, the foam layer also includes colored, organic or mine'raw pigments.

 According to a preferred embodiment of the invention, the complex coating is itself associated by heat sealing of its foam part, with an underlayment of insulation and padding which serves as a rigid support after its consolidation.

 The process for obtaining the complex coating according to the invention consists in applying by coating, on one of the faces with a decorative layer preferably chosen from nonwovens, a layer of an aqueous emulsion of polymers and / or thermoplastic copolymers which can be reactivated when hot, optionally with added barrier agents and / or opacifying agents and / or colored pigments.

 According to one embodiment of the method according to the invention, an insulation and padding underlayment, possibly preformed, is covered with said complex coating, the foam face being in contact with said underlay and it is secured to the '' by simultaneous application of heat and pressure.

 According to another embodiment, the face. foam of the complex coating is applied to the non-preformed insulation undercoat and the application of heat and pressure simultaneously ensures the shaping of the shell and its joining with the coating.

 The invention also relates to the interior fittings for motor vehicles obtained.

 The present invention will be better understood moreover and its advantages will emerge clearly from the following description of different embodiments of the method according to the invention with reference to the appended schematic drawing, the single figure of which represents a complex coating formed according to the invention, specially intended for the production of automotive trim.

 In the figure, 1 generally represents the covering essentially consisting of a decorative layer 2 with which is associated a layer of synthetic foam 4, the assembly being made integral with an underlay of insulation and padding 3.

 The sublayer 3 is a felt whose weight per m2 can vary from 500 to 2000 g and which generally consists of recovered fibers mixed with a powder of formophenolic resin or non-condensed melamine formaldehyde.

 According to a first embodiment of the method according to the invention, firstly and separately, by coating and in a conventional manner known per se, the decoration layer is deposited, which is preferably a nonwoven fabric. polyester fibers from 80 to 200 g / m2, a layer of foam of synthetic copolymers in aqueous emulsion, then the whole is dried to evaporate the water.

Synthetic copolymer foam contains
- approximately 73 parts (dry extract 50%) of a dis
aqueous persion comprising 30% of acrylic ester,
40% ethylene sinyl acetate and 30% acetate
vinyl maleate
- 7 parts (dry extract 7) of an emulsifier based
sulfonated ether and fatty acid salt, by weight
high molecular
- 10 parts of opacifying agent which is an oxide
finely crystallized titanium, rutile type
of the order of 10 microns; titanium oxide can
be of the genus anatase and can be replaced by
zinc oxide, in doses up to 50% dry / dry
- 10 parts of a product with a lamellar structure such
than mica or vermiculite, or 50 parts of
alumina silicate dry / dry.

 - mineral pigments are optionally added.

 The density of the foam thus obtained is naturally a function of the thickness of the deposit desired and is adjusted between 100 and 300 g / liter.

 The amount of foam deposited is around 60 gXm2 (dry) but it can vary depending on the research effect.

In a second step, the underlay 3 is preformed in axa mold cha'ffe thus ensuring, at the same time as the shaping of the shell, the condensation of the resin consolidating the fibers and the stiffening thereof.

This heat treatment releases the vapors which could stain the horn material 2. Finally, in a third step1, the nonwoven of decoration 2 is applied to the preformed shell, the back of which already has the foam layer 4, preheated or not moreover, and the assembly is subjected to the combined action of heat and pressure (approximately 150 ° C., pressure of the order of 2.5 kg / cm 2) for 1 minute; thermoforming of the nonwoven 2 and its joining together with the underlayer 3 are thus simultaneously ensured.

 According to a second embodiment of the method according to the invention, the forming of the two layers 2 and 3 and the solderisation of the two layers by the foam 4 are carried out simultaneously, in a single operation.

For this we have on a heated mold
- the insulation and padding layer, not ther
moformed 3, then the decor layer 2 constitutes a pre
basically a polyester nonwoven from 80 to
200 g / m2, on the reverse side of which we have placed
beforehand the layer of foam 4, then we submit
the whole for 1 minute to the action conjugate
heat and pressure (2000C - 2.5 kg / cm2).

Under the action of heat, the formophenoli-
that or melamine-formaldehyde as well as oils and
other sprayable or sublimable dyes included
in sublayer 3, will diffuse and research
in particular to penetrate into the decor layer 2, by
polyester nonwoven.

It is therefore appropriate, in this case, to modify the forum
mulation of the foam layer 4, in order to adapt it
working conditions. So we can use
for the foam the following formulation
- 73 parts (dry extract 50, ') of syn copolymer
heat reactivatable thematic which is, in
the example chosen, an acetate-maleate copolymer
vinyl, the proportion of acetate to
maleate varying between 60 and 80%
- 7 parts (dry extract 7%) of emulsifying agent, to
base of sulfonated ether and a fatty acid salt of
high molecular weight
- 5 to 10 parts of an opacifying agent such as o
titanium oxide or zinc oxide
- 100 parts of alumina silicate having the
next approximate composition
Silica 55 to 62%
. Alumina 26 to 30%
. Base (NaOH-KOE) 0.5 to 4%
. Iron oxide (Fe203) 4, '
- possibly mineral or organic pigments.

 The density of the foam thus obtained is naturally a function of the desired thickness of deposit and is adjusted between 100 and 300 g / liter.

 The amount of foam deposited is around 60 g / m2 (dry) but it can vary depending on the desired effect.

It is obvious that these are only non-limiting examples which are intended only to illustrate the invention
The use of this foam has many advantages.

 A relatively thick bonding plane is obtained, of the order of 0.5 to 1 mm, for a low weight / m2 with a reasonable price / m2.

 This bonding plane is therefore not substantially influenced by the slight variations in thickness of the support.

 The foam is deposited superficially on the back of the non-woven fabric. It only flows slightly inside the nonwoven and the shell under the combined action of heat and pressure, to ensure the bonding of the two elements, during the thermoforming operation.

 The adhesive film is elastic and does not appreciably modify the deformability of the nonwoven.

 The adhesive film remains very flexible and keeps the non-woven fabric as thick as possible.

 It is remarkably suitable for thermoforming, compensates for slight variations in thickness between the two shells, perfectly matches the contours and shapes of the mold, and makes it possible to obtain a particularly pleasant appearance.

 Finally, in the finished coating, none of the phenomena described above are observed, and in particular no trace of migration of the resin, the dyes and other fatty products contained in the insulation and padding layer 3 is visible by transparency through decor layer 2.

 There is also no phenomenon of creep of the foam layer 4 ensuring the joining-up of layers 2 and 3.

 As is obvious, and as appears from the above, the present invention is not limited to the single embodiments described above by way of nonlimiting examples, it embraces, on the contrary, all variants of them. realization, and in particular the applications of the complex coating constituted by the association of the decorative layer 2 with the foam layer 4 in fields other than those of automobile trimmings.

Claims (10)

 - CLAIMS  l - Complex coatings, characterized in that they comprise in combination a decorative layer 2, relatively thin and preferably chosen from nonwovens and a foam layer 4 of hot-reactivable synthetic copolymers, and in particular by application of high frequency , chosen from polymers and copolymers of chloride and / or vinyl esters and / or ethers, optionally added with acrylic ester.  2 - Coatings according to claim l, characterized in that the polymers and copolymers are chosen from polyvinyl chloride, ethylene vinyl acetate, vinyl acetate / maleate.  3 - Coatings according to claims 1 and 2, ca acterized in that the foam layer comprises opacifying agents chosen from titanium oxide (in rutile or anatase form) and zinc oxide.  4 - Coatings according to any one of claims t to 3, characterized in that the foam layer comprises barrier agents chosen from products with a lamellar structure such as mica, vermiculite, aluminum, bronze and copper, these last three products being in so-called "film-coating" form, that is to say laminated, according to a dry / dry percentage lying between 10 and 50, '.  5 - Coatings according to any one of claims 1 to 3, characterized in that the barrier agents are chosen from silicon derivatives such as natural or synthetic silicon oxides, sodium silicate and aluminum silicate, according to a percentage between 40 and 120% dry / dry.  6 - Coatings according to any one of claims i to 5, characterized in that the foam layer further comprises colored pigments, organic or inorganic.  7 - Coatings according to any one of claims t to 6, characterized in that they are themselves-X8me5 associated by heat sealing of their foam part with an underlayment of insulation and padding 3 which serves as their rigid support after their consolidation.  8 - Process for obtaining complex coatings according to any view of claims l to 7, characterized in that it consists in applying by coating on one of the faces with a decorative layer preferably chosen from nonwovens , a layer of foam of heat-reactivable thermoplastic polymers and / or copolymers, in aqueous emulsion, optionally supplemented with barrier agents and / or opacifying agents and / or colored pigments, and ensuring the joining together by simultaneous application of heat and pressure.  9 - A method according to claim 8, characterized in that an underlayment of insulation and padding1 possibly preformed, is covered with said complex coating, the foam face being in contact with said undercoat and it ensures the joining of the '' by simultaneous application of heat and pressure.  10 - A method according to claim 8, characterized in that the foam face of the complex coating is applied on the non-preformed insulation sublayer and the application of heat and pressure simultaneously ensures the shaping of the shell and its attachment to the coating.  II - Application of complex thermoform coatings according to any one of claims 1 to 10 to the production of interior trim for motor vehicles.