MULTI LAYER LAMINATED MOLDING

PIECE MOULEE MULTICOUCHE

English Abstract

ABSTRACT.
An extruded multi layer laminated molding incorporates
an intermediate polyolefin layer, generally in the form of a
film or tape having the property of providing non-delaminating
adherence to adjoining layers comprising a polyvinyl chloride
section on the one side and a thermoplastic rubber section on
the other side. The two sections are normally incompatible,
and use of the intermediate layer permits the use of thermo-
plastic rubber in combination with the versatility and ex-
trusion fabrication techniques developed for polyvinyl chloride.

Claims

WHAT I CLAIM BY CANADIAN LETTERS PATENT IS:

1. A composite trim section having a first extruded
portion of a thermoplastic rubber, a second portion sub-
stantially longitudinally co-extensive therewith being of
polyvinyl chloride film not generally adherable with said first
portion, said first and second portions each having a surface
area in facing relation with the other portion, an intermediate
portion located between said facing area portions of a third
material bonded in heat sealed relation to said thermplastic
rubber constituting the sole securing agent between said first
and second portions consisting of a single component poly-
olefin being in itself adherently compatible with said first
and second portions, to provide substantially non-delaminating
adhesion between said portions, said polyvinyl chloride film
having a decorative finish layer in adherent protective
relation therewith.
2. The trim section of Claim 1, said decorative finish
layer being of polyethylene teraphthalate.
3. The trim section of Claim 1, wherein said polyolefin
is polypropylene.
4. The trim section of Claim 1, wherein said polyvinyl
chloride film is a tape having said polyolefin secured in
adhering relation to one face thereof.
5. The trim section of Claim 4, wherein said polyolefin
is bonded to said extruded portion of thermoplastic rubber
simultaneously with the extrusion thereof.

Description

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This invention is direc-ted to elongated decorative
and protective lamina-te moldîngs, including trim as used in
the automotive industry.
Elongated moldings are used for protecive and
decorative purposes~ such as cove base trim in households
and body molding trim in the automotive industry, to name bu-t
two such applications.
Trim is generally derived from petro-chemical stock
primarily in the form of polyvinyl chloride (PVC)~ Another
family of material, thermoplastic rubbers (TPRis) provide
a number of significant practical advantages over PVC, owing
to the absence of platlcizers in the TPR's and their dimensional
stability, characterized by substantial non-shrinkage together
with lower density and smooth "running" characteristics which
facilitate ready extrusion. ~Iowever9 TPR~s do not laminate
with PVC, nor do TPR's bond to polyethylene -terapthalate
(MYLARtm) so that to-date it has no-t been possible to utilize
existing developed PVC -techniques for the fabricatlon and
decora-tion of trim incorpora-ting TPR's.
I-t has been found -that the non-laminatlng relation-
shlp between TPR's and PVC can be overcome, using a sui-table
solid polyolefin la~er in-terposed between the TPR and PVC :in
bondin~, isolating relation with the two other materials.
Thus, -the provision of ~the adhesion system herein
set for~th permits the ready bonding of normally incompa-tible
materials in an e~truslon system utilizing the superior flow
aspects of TPR'sg generally by simultaneous e~-trusion and
bonding to the intermediate layer~ as coated on a PVC -tape~
The present invention thus pxovides a composite
trim sec-tion having a firs-t e~truded section portion of




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thermoplastic rubber, a second section portion substantially
longitudinally coextensive therewith, being of polyvinyl
chloride not generally adherable wi-th the first por-tion,
the first and second portions each having a surface area in
facing relation with the other portion, and an intermediate
portion located in isolating rela-tion between the first and
second portions and constituting a single componen-t non-
liquid polyolefin adheren~y compatibl.e with the material of
the first and second portions, to provide substantially
non-delaminating adhesion between the portions~
The subject trim comprises an elongate structure
of substantially uniform cross section sandwich construc-tion
consis-ting essentially of a bonded ~tri-lamina~te structure
having two adhesively incompatible layers, one layer com-
prising thermoplastic rubber and the other a polyvinyl
chloride having an intermediate layer comprising a single
componen~t polyolefin plastic being in itself mutually ad-
hesively compatible with the other layers and cons-ti-tu-ting
the sole fàstening agen-t securing the o-ther layers in
secured, substan-tially non-delaminating rela-tion.
A poleolefin such as polypropylene of a wea-therable
-type resis~tanct~ to ultra violet degredation is well suited
.~or -the subject use,
Certain embodiments of -the invention are described
wherein:
~igure 1 is a schematic cross-section of a possible
composite section according to the present
invention having the elements therof in
exploded relation;
~igure 2 is a preferred embodiment showing a
more typical form, and


~igure 3 i5 an alternatLve section that is contem-
plated.
The schematic section 12 of Figure 1 has a base
section 14 of TPR, an intermediate layer 16 of polyoleifn
and an upper layer 18 of PVC.
In the Figure 2 embodiment, which more closely
resembles a typical molding, the sectlon 22 comprises a
shaped, extruded base secti.on 24 of TPR, an lntermediate
layer 26 of polypropylene adhering thereto, having an upper
layer 28 of PVC adhering to the layer 26.
In the Figure 3 embodiment it is con-templated that
the particular characteristics of the materials facilitates
-the provision o~ a hollow composite section 32 having a
base section 34 of TPR~ intermediate edge layers 36 ofpoly-
propylene, and an upper layer 38 of PVC. ~s before stated,
the polypropylene will for most usages be of the wea-therable
type, capable of withstanding ultra-violet degradation by
sunlight.
The form of trim shown in ~igure 2 is then suited
for completion by the addition of mylar and other decorative
finishes to -the PVC, by established procedures, including
the provision of additional protective fini.shes. In this
regard, the relative shapes of -the sections are not limited
t,o -the embodiments illus-trated.
In the ~igure 2 embodimen-t~ the portions 28 may
comprises a PVC tape having a thickness such as 5 mil (0~005
inches), the polypropylene layer 2~ possible being a
desposition of abou-t 1 mil, to provide the desired adh.esion,
by pressurized thermal bondi.ng to -the base 24.
While polypropylene is specifically disclosed as
having the desired bonding characteristic -to both PVC and
to TPR, it is anticipated that o-ther polyolefins also possess
sati.sfactory bondi.ng characteristics to both classes of

substance to pro~ide utility.