Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The inven-tion rel~-tes -to matt and scratch-resistant,
amorphous -to crystalline films of -thermoplastics which are
filled with glass spheres.
To manufacture mat-ted films it is customary to convert
thermoplastic moulding compositions filled with fillers, for
example wi-th ti-tanlum dioxide, in-to films. These films have
the disadvantage that the surfaces can be scratched relatively
easily, which restricts the range of applications, for exclmple
the use as the top layer in a veneering ma-terial for furni-ture
or doors.
Thermoplastic moulding compositions which contain glass
fibres and/or glass spheres as a reinforcing and filling mate-
rial are also known. These moulding materials are used for
the manufacture of injection mouldings. For example,
W. Kn8ss, Glaskugeln ("Glass Spheresi'), Industrieanzeiger 93,
No~ 72, 1971, 1835 - 1838 and J. Ritter, Applied Polymer
Symposium No. 15, 1971, 239 - 261 describe the general proper-
ties of such injection mouldings of polyamides !filled with glass
spheres and also mention that polyesters can be us~ as-theplastlcs.
Japanese Published Patent 73/05,257 describes moulding composi-
tions of polyethylene terephthalate, reinforced with glass
fibres and glass spheres, which are suitable for use in injec-
tion moulding, and DT-OS 2,206,804 describes polybutylene tere-
phthalates which con-tain either glass fibres or glass spherQs
and can also be used for the manufacture of injection mouldings.
However, none of these publications mentions that high quality
films with certain surface properties can be manufac-tured from
thermoplastic moulding compositions reinforced with glass
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spheres. Fur-thermore, so-called "reflec-ting films", which
consist of a -thermoplastic and of which the surface is coated
wi-th glass spheres, are already known. Since the gl~ss
spheres are glued to these films, the scra-tch resistance of
the ~ilms is only low.The invention is based on the objec-t of
providing a shee-t ma-terial or film ma-terial which has increased
scra-tch resis-tance for a given degree of mat-tness.
It has now been fo~md that films or sheets are matted
and at the same time scratch-resis-tan-t if they contain glass
spheres and the surface structure is formed by domes of the
glass spheres which are still completely covered by thermo-
plastic ma-terial. Surprisingly, -these films show no flaws,
even in the case of thin films, and the strength of the films
is no-t influenced adversely by the glass sphere filler. The
matting of the surface is achieved in this case through the
fact that the incident light undergoes diffuse scattering by
the special surface structure.
Accordingly, the subject of the present invention are
matted and scratch-resistant, amorphous to crystalline, films
or sheets of film-forming thermoplastics and a filler, charac-
terised in that the films or sheets contain 2 to 25% by weight,
based on the weight of the polymer, of glass spheres of size
from 0.5 to 75 ~, and that the domes of the glass spheres which
project from the surface are also completely covered by the
plastic.
Preferably7 the films or sheets con-taln 5 to 15% by
weigh-t, especially 5.5 to 12~ by weight, of glass spheres and
preferably the average size of the glass spheres is 0.5 to 20 ~1.
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The films or shee-ts are manu~actured by ~eans of known
devices from moulding compositions in which -the glass spheres
are uniformly distributed in the thermoplas-tic. Sui-t~ble
plastics are all film forming polymers. Plas-tics
from which very -thin films can be manufac-tured are preferred.
Par-ticularly suitable plas-tics for -the manufacture of -the films
or sheets according to the invention have proved to be poly-
alkylene terephthalates, especially polyethylene tereph-thalates,
and polyamldes, especially polyamide 6~ polyamide 6,6 9 poly-
amide 11 and polyamide 12.
The plastic moulding compositions can contain custom-
ary further additives, such as, for example 9 fillers, matting
agents, such as micro-mica, titanium dioxide or suitable color-
ants. As a further matting additive, preferably 0.01 to 5,
and especially 0.1 to 2% by weight of micro-mica is admixed to
the moulding compositlon. Furthermore, flameproofing sub-
stances, for example tetrabromophthalic anhydride or decabromo-
diphenyl can be present, optionally together with antimony
trioxide. In order to prevent the films or sheets according
to the inven-tion sticking to the surfaces of -the tools during
manufac-ture or during further processing, known mould release
agents, such as, for example, polye-thylene, waxes or silicones,
can be added to the moulding compositions.
- The content and especially the size of the glass spheres
depends on the film thickness and on the desired mat-tness. It
has proved desirable that the average diameter of the glass
spheres should be less than hal~ the film thickness. To
assist the flawless embedding of the glass spheres in the
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plastic matrix, an adhesion-promo-tLng substance can be used in
addition. In that case, the adhesion promo-ter can be added
-together with the glass spheres -to -the plastic, or can be
applied -to the surface of the glass spheres before these are
mixed with -the plas-tic. Adhesion promoters which can be used
are in particular -the compositions described as "si~es" w~ich
are known for binding glass fibres or glass particles to plas-
tics in which they are embedded.
The manufacture of the films according to the inven-
tion is carried out with devices known for the purpose. To
produce -the films, the thermoplastic moulding compositions,
which contain, uniformly distributed, 2 to 25% by weight of
glass spheres of slze from 0.5 to 75 ~, are converted -to a
layer by extrusion from a slit die or circular die and
stretched, while still in the molten sta-te, to -the point that
the surface structure of the films or sheets is formed by pro-
jecting domes of the glass spheres, which are still completely
cavered by plastic.
The degree of crystallinity of the films or sheets
according to -the invention can be con-trolled by the ra-te of
cooling after extrusion, If rapid cooling is used, amorphous
to slightly crystalline, translucent films or sheets are
obtained,whilst on slower cooling predominantly more crystal-
line products are obtained. The amorphous to slightly
crystalline films or sheets according to -the invention can also
be converted in-to films of high degree of crystallinity by a
subsequent heat treatment. The amorphous -to slightly crystal~
line films or sheets can also first be warmed and thenbe
1~Eii1973
stretched biaxially, whereby crys-lalline films or sheets of
increased strength are obtained.
The scratch-resistant film material ac~ording -to the
invention can be laminated to o-ther materials, for example
wood, glass, metal or o-ther plastics, ancL the customary adhes-
ion promoters can be use~ for this purpose. Depending on the
nature o~ the materials, an appropriate adhesion promoter will
be employed, say an adhesion promoter which can be heat-
activated and which has beforehand been applied either to the
film material according to the invention or to the material to
which the latter is to be laminated. In the case of lamina-
tion of the films according to the invention to other plastic
films, pre~erably, for example, of PVC, polyethylene, chlorina-
ted polyethylene, ethylene/vinyl acetate, polystyrene or copoly-
mers of, for example, acrylonitrile, butadiene and styrene, an
alternative procedure is to extrude the films simultaneously
and bond them to one another whilst still in the molten state.
m e film material according to the invention can be
embossed in order to apply a pattern, wi-thout changing the sur-
face structure consis-ting of domes (of the spheres). Accord-
ingly, the matting and the scratch resistance are retained
even after the embossing process. The embossing can also be
carried out with laminated films of the material according to
the invention and other plastics. Here, the embossing is
also formed on the lower film if its softening point is lower
than that of the material according to the invention.
A preferred field of use for the film material accord-
ing to the invention is the manufacture of veneer materials,
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for example for furni-ture manu-Eacture, for doors or for wall
claddings. For -this pu~pose, it is possible -to use -the
films according to the invention, provided with a veneer pa-t-
tern, or -to use embossed laminated films. It is also possible
to lamina-te a film, for example of rigid PVC, which has been
provided with a veneer pa-t-tern, to -the film material according
to the inven-tion. In -this way, a surface coating which has
substantially better scratch resistance -than l~nown comparable
materials is ob-tained in every case.
The attached figure explains the invention in relation
to a laminate film. In this figure, 10 represen-ts a base
layer of a Eilm-forming plastic, 12 represents an adhesive
layer and 14 represents a film according to the invention.
It can be seen that spheres (16) are inc~xra~in the
layer (l4), and in particulàr in such a way that the surfaces
of the film according to the invention have a dome structure
which is charac-terised in that the individual spheres (16) are
enclosed by a continuous skin of the plastic matrix.
The examples which follow serve -to explain the inven-
tion further. The scratch resistance was determined relative
to a rigid PVC film, using a missile resistance tester, ~ype L~35
fromMessrsErichsen GmbH and employing a round disc of a
special plastic as the missile. The percentages quo-ted are
percentages by weight.
Example 1:
In the course of the polycondensation of a polyethyl--
ene terephthalate, 5% oE glass beads of average diame-ter 5-
15 ~9 ~ e~=~ BALLOTINI 5,000 (CP 02) were added. (These
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beads are manufact~red by Messrs Potters Ballotoni GmbH,
6719 Kirchheimbolanden). The polycondensa-te was extruded on
a customary slit-die film installa-tion under conditions such
that the material temperature was 270C a-t the outle-t posi-tion
m e ~el-t which issues vertically from -the 300 ~ die gap was
cast onto a cus-tomary cooling roller arrangement. The
temperature of the firs-t cooling roller was 70C. '~he ratio
of the roller speed to -the ou-tlet speed of the melt was so cho-
sen that the film, in the molten state, was stretched uniformly
in the longitudinal direction to a thickness of 30 ~. The
predominantly amorphous film showed a matt surface which~ as
was found from screen elec-tron microscope photographs, was
caused by homogeneously distributed glass beads completely
surrounded by the polymeric ma-trix. These pho-tographs showed
that even glass spheres which project from the surface by up to
90% of their diameter, were surrounded (by matrix) without
micro-flaws.
This film was laminated lo a known rigid PVC film,
using commercially available adhesives, and embossed at film
~emperatures of 150C under otherwise customary conditions.
As a result of the prewarming before the embossing nip the
film crystallised further~ so that it only softens completely
after exceeding the crystalli-te melting point at approx. 2~0C.
; Irl the embossing nip itself~ the coarse s-tructure of
the embossing roller was -transferred under the temperature
and pressure conditions prevailing in the nip, without however
pressing the domes into the surface. The embossing of the
; film surface was thus fixed predominantly by the PVC film,
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withou-t depic-ting the peak--to-valley heights of the embossing
roller. It was possible to show, by screen electron micro-
scope photographs, -that the "dome structure" Oî -the PET fi]m
is still presen-t in the embossed laminate also.
The film has approximately the same degree of ma-t-tness
as a rigid PVC film embossed with a matt sa-tin finish~ and has
good scratch resistance. The missile resistance tes-t showed
that a rigid PVC film already showed a glossy trace under a
load of 150 gram force, whilst in -the case of -the film accord-
ing to the invention no trace was detectable even at 2,000 gram
~orce.
Example 2
A PET/glass bead mixture manufactured from the same
product and by the same process, but with 15% of glass beads
added, was extruded on a customary film-blowing installation,
at material temperatures of approx. 265C, from a circular die
of 0.5 mm gap width to give 50 ~ thick films by even stretching
in two directions at right angles to one another. These films
were considerably more matt than those obtained according -to
Example 1. The screen electron microscope photographs showed
a substantially larger number of homogeneously distributed
domes which were again completely surrounded by the polymer.
Lamination and embossing was carried out analogously to
-Example 1. The embossed laminate was considerably more matt
and had comparable scratch resis-tance.
Example 3-
A film was extruded from a polyethylene t~rephthala-te
according -to Example 1, which however additionally contained
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0.1% of TiO27 in accordance wi-th -the process mentioned in
Example l; the film was comparatively somewhat more matt.
The screen electron microscope pho-tographsshowed that
the pigments of particle size less than 0.5 ~ con-tributed only
li-ttle to light scattering on -the surface but caused increased
reflection of the incident light. The lamination and emboss-
ing were carried out as indicated in Example 1.
The embossed film larninate was somewhat more matt than
tha-t described in Example 1.
Example 4:
10% of glass beads were admixed to a polycaprolac-tam
6,6. This product was extruded on the slit die insta]lation
described above, at material temperatures of 250C, onto a rol-
ler cooled to plus 10C, so as to give a predominantly amor-
phous film. The film, again in the plastic state, was
stretched uniformly, from 300 to 30 ~, in directions at right
angles to one anot,her.
The surface structure was comparable with that men-
tioned in Example 1. This film was laminated and embossed
in accordance with the process indicated in Example 1, using
embossing temperatures of 150C. The screen electron micro-
scope photographs again showed the surface structure consist-
ing of domes.
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A two-layer film of a polyeth~lene terephthalate con-
taining 10% of glass beads (Crastin XB 2813) - layer 1 - and
OI an ethyiene/vinyl acetate copolymer (EVA~ VA con-ten-t 32%,
melt index 30 g/10 minutes) - layer 2 - was produced on a slit
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die co-extrusion installa-tion.
With the sli-t die used, the ma-terial ch&nnels for
layers l &nd 2 were respectively fed by single scre~ extruders
of 90 &nd 60 mm ~ and -the melts of -the -two ma-terials were corn-
bined with one ano-ther approx. 50 mm before -the end of the
die, The -temperatures on -the extruder were so chosen that
the material -temperature of the polye-thyLene tereph-thalate was
approx. 275C &nd that of -the EVA approx. 220C. The die
temperatures were set -to 280C~ resulting in a temperature of
270C in the melt which issued. The gap wid-th was 0.5 mm
&nd the final film thickness was 200 ~ because of the plastic
stre-tching of the melt. The layer thickness ra-tio was adjusted
~y adjusting the feed rate so that the adhesion promoter layer
was approx. 20 ~ thick and the surface layer approx. 180
thick.
Because of the abovementioned plastic stretching of the
melt, the dome-shaped surface, &nd hence the desired matting,
were obtained. m e second layer, which does not contain &ny
special fillers, in contrast remains completely smooth. The
film thus manufactured is particularly suitable for lamination
to other thermoplastic films o~ continuous laminating machines,
since it is possible to avoid trapping air.
m is two-layer film C&n furthermore also be laminated
thermally or by means of known adhesive systems and processes
onto other web-shaped materials, for example fleece or paper,
or onto wooden materials in sheet form.
During the polycondensation of a polyethylene
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terephthalate, r)% (corresponding -to Example 1) o~ the glass
beads mentioned in E~c~mple 1 were added to one mixture, and 6%
to another mix-ture~
; 1% of micro-mica was then also added to the first-
mentioned mixture, con-taining 5% of glass beads, during extru-
sion processing - as described in Example 1.
The predominantly amorphous films obtained from both
polymers were laminated onto prin-ted rigid PVC films in the
usual manner, and embossed at the same time. The printing
inks were based on an acrylate polymer which at the same time
serves as an adhesion promoter between the PETP film and the
rigid PVC film. The film in which 1% of micro-mica was used,
the filler content being the same, has be-t-ter transparency,
comparable scratch resistance and greater ma-ttness.
This higher degree of mattness and lower cloudiness is
particularly important in imitating natural veneers since the
film laminated onto the original printed p~ttern should falsify
the latter as little as possible.
The micro-mica used in this case was obtained via the
German agent P.H. Erbsloeh, D-4 Dusseldorf, from Norwegian
Talk, 5001 Bergen, Norway. 0Ø 744 (type Micro Mica U 1).
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