The present invention relates to an impregnated layered product usable
as a soundproofing element in vehicles.
As it is known, preformed or flat layered products with thermal insulation
and/or soundproofing functions are currently installed in motor vehicles.
These layered products are constituted by a variety of materials,
whose type changes depending on the required performance, on the dimensions and
on the regions where each component is fitted.
Some of these layered products, mainly for soundproofing uses, are
self-supporting, rigid, and medium-large in size, and are fitted for example in
roofs (roof panels).
They are usually sandwiches, an example of which is constituted in
- a monolayer of low-weight non-woven fabric, composed of synthetic fibers and
acting as a barrier and support (approximately 50 mg/m2)
- at least one layer of glass fiber, deposited onto the non-woven fabric together
with a bonding agent, which usually has a polyurethane base, in order to produce
an assembly of all these components (approximately 100 g/m2 of glass
and approximately 50 g/m2 of bonding agent)
- a polyurethane mat (with a load-bearing function) that weighs approximately
200 g/m2 and is approximately 1 cm thick, on both surfaces of which a
thermosetting polyurethane bonding agent is applied in an amount approximately equal
to 75 g/m2 for each surface
- at least one layer of glass fiber, like on the opposite side
- a monolayer of non-woven fabric, like on the opposite side.
Finally, the resulting sandwich is placed in a mold, where thermoforming
takes place (130 °C); the finished part weighs approximately 750 g/m2.
The central mat of the sandwich can also be constituted by other materials,
such as for example mixed textile fibers pretreated with powdered thermosetting
In this case, the preforming temperature must reach 180 °C, while
the weight of the mat rises to 700 g/m2, bringing the weight of the finished
part to 1250 g/m2.
The main positive characteristics of these layered products are:
- compliance with climatic chamber tests and flexural strength tests prescribed
in this field
- excellent reaction to fire
- excellent rigidity
- low weight
- one-person fitting allowed thanks to its self-supporting ability and low weight
- low costs, due both to weight reduction and to the fact that glass fiber is
a low-cost raw material.
However, there are also drawbacks, which are due mainly to the presence
of the glass fiber, such as:
- bad environmental characteristics (during production and due to the fact that
the glass fiber, over time and due to vibrations, tends to form microfibrils)
- lack of recyclability
- insufficient acoustic and thermal performance
- increase in the percentage of rejects during fitting (due to the lack of elasticity,
especially in large components).
The aim of the present invention is to provide an impregnated layered
product that can be used as a soundproofing element in vehicles and eliminates the
drawbacks noted above in known types.
Within this aim, an object of the invention is to provide a layered
product that can be manufactured without particular technological complications
with respect to known products.
Another object is to provide a layered product that can be manufactured
by using current equipment.
This aim and these and other objects that will become better apparent
hereinafter are achieved by a layered product usable as a soundproofing element
in vehicles, comprising a layer constituted by a load-bearing mat, characterized
in that it further comprises at least one layer of non-woven fabric made of fibers
of thermoplastic materials impregnated with resins selected among thermosetting
resins and thermoplastic resins with the addition of crosslinking agents, said layer
being bonded so as to cover at least one side of said load-bearing mat.
Further characteristics and advantages of the present invention will
become better apparent from the following detailed description of a preferred but
not exclusive embodiment thereof, illustrated by way of nonlimiting example in the
accompanying drawing, wherein the only figure is a schematic sectional view of a
layered product according to the invention.
With reference to the figure, a layered product according to the invention
can be constituted by the following sandwich:
- at least one layer 10 of non-woven fabric made of fibers of thermoplastic materials
such as polyester, impregnated with resins selected among thermosetting resins,
such as resols, thermoplastic resins, such as acrylic resins with the addition of
crosslinking agents such as melamine resins and/or urea resins,
- a load-bearing mat 11, which can be conveniently made of polyurethane weighing
approximately 200 g/m2 and approximately 1 cm thick, to which a thermosetting
polyurethane bonding agent, corresponding to approximately 65 g/m2 per
side, has been applied to the surface to be coupled to said at least one layer 10,
- at least one layer 12 of non-woven fabric, like on the opposite side.
For the layers 10 and 12, it is conveniently possible to use, for
example, a non-woven pile fabric of polyester fibers, impregnated with 210 g/m2
of resol, known commercially as "Valfeltro 198 FR Plus" and manufactured by the
company O.R.V. Ovattificio Resinatura Valpadana in Grantorto (Padua).
The resulting sandwich is placed under a mold, where thermoforming
is performed (130 °C).
The finished product weighs approximately 750 g/m2.
For the layers 10 and 12, it is in any case possible to use advantageously
all the resin-impregnated non-woven fabrics that are currently known per se for
the manufacture of bituminous coatings in waterproofing work.
These non-woven fabrics are appreciated thanks to their high longitudinal
tensile strength, low longitudinal tensile elongation, high resistance to temperatures,
high tear resistance, low size shrinkage during application, installation and over
time, high permeability, all of these characteristics making them ideal for bitumen
treatment (an operation performed at approximately 180 °C).
With the particular application in co-molded soundproofing layered
products for the car or automotive sector in general, these non-woven fabrics have
also revealed additional performance aspects that they achieve with respect to known
soundproofing layered products that use glass fiber:
- improved environmental characteristics
- sufficient acoustic and thermal performance
- improved recyclability
- good reaction to fire
- low weight
- good rigidity associated with sufficient elasticity
- easier fitting (large roof panels can be fitted by a single person)
- cost reduction (the cost of the layered products is comparable to that of glass
fibers with accessories)
- low percentage of rejects during fitting.
In practice it has been found that the present invention has achieved
the intended aim and objects.
All the technical details may further be replaced with other technically
The materials, so long as they are compatible with the contingent
use, as well as the dimensions, may be any according to requirements. The disclosures
in Italian Patent Application No. PD2003A000058 from which this application claims
priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference
signs, those reference signs have been included for the sole purpose of increasing
the intelligibility of the claims and accordingly, such reference signs do not have
any limiting effect on the interpretation of each element identified by way of example
by such reference signs.