U.S. patent application number 13/104197 was filed with the patent office on 2011-12-01 for polymer composition having heat-absorbing properties and improved colour properties.
This patent application is currently assigned to Bayer MaterialScience AG. Invention is credited to Sven Gestermann, Klaus Horn, Gianmaria Malvestiti, Alexander Meyer, Birgit Meyer Zu Berstenhorst, Jorg Reichenauer, Andrea Scagnelli, Gunther Stollwerck, Massimo Tironi.
Application Number | 20110293921 13/104197 |
Document ID | / |
Family ID | 42735276 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110293921 |
Kind Code |
A1 |
Meyer; Alexander ; et
al. |
December 1, 2011 |
POLYMER COMPOSITION HAVING HEAT-ABSORBING PROPERTIES AND IMPROVED
COLOUR PROPERTIES
Abstract
An embodiment of the present invention relates to a composition
comprising a) at least one transparent thermoplastic material; b)
at least one inorganic IR absorber comprising at least one boride
compound present in an amount of from 0.0015 wt. % to 0.015 wt. %,
calculated as solids content of boride in the total polymer
composition; and c) at least one inorganic, nano-scale pigment
present in an amount of from 0.0008 wt. % to 0.0035 wt. %, based on
the total composition; and d) optionally further additives.
Inventors: |
Meyer; Alexander;
(Dusseldorf, DE) ; Stollwerck; Gunther; (Krefeld,
DE) ; Gestermann; Sven; (Leverkusen, DE) ;
Horn; Klaus; (Dormagen, DE) ; Meyer Zu Berstenhorst;
Birgit; (Moers, DE) ; Reichenauer; Jorg;
(Krefeld, DE) ; Scagnelli; Andrea; (Bonate Sotto
(BG), IT) ; Malvestiti; Gianmaria; (Brembate (BG),
IT) ; Tironi; Massimo; (Treviolo (BG), IT) |
Assignee: |
Bayer MaterialScience AG
Leverkusen
DE
|
Family ID: |
42735276 |
Appl. No.: |
13/104197 |
Filed: |
May 10, 2011 |
Current U.S.
Class: |
428/323 ;
252/586; 428/402; 977/753 |
Current CPC
Class: |
Y10T 428/25 20150115;
C08K 5/50 20130101; C08K 3/38 20130101; Y10T 428/2982 20150115;
C08K 5/0041 20130101; C08L 69/00 20130101; C08L 69/00 20130101;
C08K 3/013 20180101; C08K 3/38 20130101; C08K 3/04 20130101; C08K
2201/011 20130101; C08K 3/04 20130101 |
Class at
Publication: |
428/323 ;
428/402; 252/586; 977/753 |
International
Class: |
B32B 5/16 20060101
B32B005/16; G02B 5/23 20060101 G02B005/23 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2010 |
IT |
RM2010A000225 |
Claims
1. A composition comprising a. at least one transparent
thermoplastic material; b. at least one inorganic IR absorber
comprising at least one boride compound present in an amount of
from 0.0015 wt. % to 0.015 wt. %, calculated as solids content of
boride in the total polymer composition; and c. at least one
inorganic, nano-scale pigment present in an amount of from 0.0008
wt. % to 0.0035 wt. %, based on the total composition; and d.
optionally further additives.
2. The composition according to claim 1, wherein the ratio of b) to
c) is from 20:1 to 0.4:1.
3. The composition according to claim 1, wherein the ratio of b) to
c) is from 5:1 to 1.5:1,
4. The composition according to claim 1, wherein the at least one
boride compound is selected from the group consisting of type MxBy
wherein M represents La, Ce, Pr, Nd, Tb, Dy, Ho, Y, Sm, Eu, ER, Tm,
Yb, Lu, Sr, Ti, Zr, Hf, V, Ta, Cr, Mo, W and Ca.
5. The composition according to claim 1, wherein the at least one
boride compound comprises LaB.sub.6.
6. The composition according to claim 1, wherein the at least one
inorganic, nano-scale pigment comprises carbon black.
7. The composition according to claim 1, wherein the at least one
inorganic, nano-scale pigment comprises a carbon black having a
mean particle size of less than 100 nm.
8. The composition according to claim 1, wherein the transparent
thermoplastic material comprises a compound selected from the group
consisting of polymethyl methacrylates, polycarbonates,
copolycarbonates, polyesters, and mixtures thereof.
9. The composition according to claim 1, wherein the composition
further comprises triphenylphosphine.
10. The composition according to claim 1, wherein the composition
further comprises at least one additive selected from the group
consisting of ultraviolet absorbers, colouring agents, demoulding
agents, flameproofing agents and heat stabilizers.
11. The composition according to claim 1, wherein the composition
has a b*(60.degree.) value of from -2.5 to 0.
12. A masterbatch comprising a. from 85 wt. % to 98.9 wt. % of a
transparent thermoplastic material; b. from 0.1 wt. % to 2 wt. % of
a boride as inorganic IR absorber; and c. from 1 wt. % to 4.8 wt. %
of a dispersing agent; d. optionally from 0 wt. % to 0.2 wt. % of
at least one stabilizer selected from the group consisting
essentially of phosphines, phosphites and phenolic antioxidants and
mixtures thereof; e. optionally from 0.001 wt. % to 0.2 wt. % of an
inorganic nano-scale pigment; f. optionally from 0 wt. % to 8 wt. %
of at least one further auxiliary substance and/or at least one
additive, wherein the sum of components a to f is 100 wt. %.
13. The masterbatch according to claim 12, wherein the transparent
thermoplastic material is present in an amount of from 93 wt. % to
98.9 wt. %.
14. The masterbatch according to claim 12, wherein the boride as
inorganic IR absorber comprises LaB.sub.6.
15. The masterbatch according to claim 12, wherein the inorganic
nano-scale pigment comprises carbon black.
16. A method which comprises adding carbon black to a polymer
composition which comprises nano-scale particles wherein the
scattering caused by the nano-scale particles is reduced.
17. An automobile, railway vehicle, aircraft or architectural
glazing comprising the composition according to claim 1.
18. A multilayer product comprising at least one layer produced
from the composition according to claim 1, at least one anti-UV
layer, and optionally a scratch-resistant coating.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit to Italian Patent
Application No. RM 2010A000225, filed May 10, 2010, which is
incorporated herein by reference in its entirety for all useful
purposes.
BACKGROUND
[0002] Glazing made from compositions containing transparent
thermoplastic polymers such as, for example, polycarbonate offer
many advantages over conventional glazing made of glass for use in
the automotive sector and for buildings. Such advantages include,
for example, increased break resistance and/or an increased weight
saving, which in the case of automotive glazing permit greater
safety for the occupants in the event of road traffic accidents and
a lower fuel consumption. Finally, transparent materials containing
transparent thermoplastic polymers permit substantially greater
freedom in terms of design because they are easier to mould.
[0003] It is a disadvantage, however, that the high heat
transmissibility (i.e. transmissibility for IR radiation) of
transparent thermoplastic polymers leads to undesirable heating of
the inside of motor vehicles and buildings under the action of the
sun. The raised temperatures on the inside reduce the comfort for
the occupants or residents and can involve increased demands in
terms of air conditioning, which in turn increase the energy
consumption and thus eliminate the positive effects again. In order
nevertheless to meet the demand for low energy consumption coupled
with a high degree of comfort for the occupants, glazing provided
with appropriate heat protection is required. This is true for the
automotive sector in particular.
[0004] As has long been known, the largest part of solar energy,
apart from the visible range of light between 400 nm and 750 nm, is
accounted for by the near-infrared (NIR) range between 750 nm and
2500 nm. Penetrating solar radiation is absorbed inside a car, for
example, and emitted as long-wave heat radiation having a
wavelength of from 5 .mu.m to 15 .mu.m. Because conventional
glazing materials--in particular thermoplastic polymers that are
transparent in the visible range--are not transparent in that
range, the heat radiation is unable to radiate to the outside. A
greenhouse effect is obtained and the interior heats up. In order
to keep this effect to a minimum, the transmission of the glazing
in the NIR should therefore be minimised as far as possible.
Conventional transparent thermoplastic polymers such as, for
example, polycarbonate are, however, transparent both in the
visible range and in the NIR.
[0005] Additives, for example, which exhibit as low a transparency
as possible in the NIR without adversely affecting the transparency
in the visible range of the spectrum are therefore required.
[0006] Of the transparent thermoplastic plastics, polymers based on
polymethyl methacrylate (PMMA) and polycarbonate are particularly
suitable for use as a glazing material. Because of its high
strength, polycarbonate in particular has a very good property
profile for such uses.
[0007] In order to impart infrared-absorbing properties to these
plastics, corresponding infrared absorbers are therefore used as
additives. IR absorber systems which have a broad absorption
spectrum in the NIR range (near-infrared, 750 nm-2500 nm) while at
the same time having low absorption in the visible range (low
inherent colour) are of particular interest for that purpose. The
corresponding polymer compositions should additionally have high
heat stability as well as excellent light stability.
[0008] A large number of IR absorbers based on organic or inorganic
materials which can be used in transparent thermoplastics are
known. A selection of such materials is described, for example, in
J. Fabian, H. Nakazumi, H. Matsuoka, Chem. Rev. 92, 1197 (1992), in
U.S. Pat. No. 5,712,332 or JP-A 06240146.
[0009] IR-absorbing additives based on organic materials frequently
have the disadvantage, however, that they exhibit poor stability
towards thermal stress or radiation. Accordingly, many of these
additives do not have sufficient heat stability to be incorporated
into transparent thermoplastics because temperatures of up to
350.degree. C. are required for their processing. Moreover, during
use, glazing is often exposed for prolonged periods to temperatures
of more than 50.degree. C., caused by solar radiation, which can
lead to decomposition or degradation of the organic absorbents.
[0010] Furthermore, organic IR absorbers frequently do not have a
sufficiently broad absorption band in the NIR range, so that their
use as IR absorbers in glazing materials is inefficient, a
pronounced inherent colour of such systems often also occurring,
which is generally undesirable.
[0011] IR-absorbing additives based on inorganic materials are
frequently markedly more stable as compared with organic additives.
The use of such systems is often also more economical because in
most cases they have a markedly more favourable price/performance
ratio. Accordingly, materials based on finely divided borides, such
as, for example, lanthanum hexaboride, have proved to be efficient
IR absorbers because they have a broad absorption band in the IR
range coupled with high heat stability.
[0012] IR-absorbing additives from the group of the borates are
suitable for transparent thermoplastics such as polymethyl
methacrylate and polycarbonate on account of the advantages
described above. However, it has been shown that these additives
lead to unexpected colour impressions in transparent thermoplastic
compositions, irrespective of their inherent colour.
[0013] The colour impression of a non-transparent object is
attributable to the reflected light. An object which, for example,
absorbs the long-wave constituents of light appears blue because
the remaining shorter-wave components of the spectrum are remitted.
However, this application relates to transparent objects, such as,
for example, window panels. Transparent objects are here understood
as being bodies that exhibit a transmission of at least 6% and a
haze of less than 3%, preferably less than 2.5%, more preferably
less than 2.0%. In the case of transparent bodies, in contrast to
non-transparent objects, it is normally not the remitted colour but
the transmitted colour that is in the foreground.
[0014] The object thus acts as a colour filter. In order not to
impair the transparency of the panel there are preferably used
colouring agents which dissolve in the polymer matrix or have such
a small particle size that they cause no haze, no haze within the
scope of the present invention meaning a haze of less than 3% at a
given layer thickness, measured in accordance with ASTM D1003.
[0015] The boride-based IR absorber particles that are used do not
in fact lead to haze of the corresponding glazing element
(haze<3%).
[0016] However, it has been found that, above a certain
concentration, these particles, whose size is preferably within the
nanometre range, can cause scattering effects in the matrix in
which they are embedded, regardless of the nature and other
properties of the particles. While this scattering has only an
unnoticeable effect on the transmission and accordingly the
transparency of the article, the colour impression of the article
is in some cases changed considerably by the scattered light, in
particular in dependence on the viewing angle.
[0017] Consequently, the IR-absorbing additives from the group of
the borides lead to undesirable colour reflexes in the finished
part, that is to say, for example, in a transparent panel, under
certain light conditions and viewing angles. Thus, corresponding
panels exhibit a bluish to violet tinge according to the
concentration of the inorganic IR absorber used. As has been
described, this colour impression is not the result of the colour
of the chosen added pigments and absorbers but is attributable to
scattering effects of the nanoparticles, which are to be observed
in particular at viewing angles of from 1 to 60.degree.. Such
scattering can adversely affect the overall colour impression of
the corresponding article, for example a vehicle or a building.
[0018] The scattering effect is, as described, frequently perceived
as a bluish-violet colour. A neutral colour impression is
frequently desirable, that is to say the natural colour impression
is not disturbed by scattering effects. This means that the colour
produced by the scattering effect must on the one hand be
relatively close to the achromatic point and on the other hand
close to the inherent colour of the component.
[0019] It must be emphasised that this colour effect is not caused
by the normal absorbed or transmitted colour. This phenomenon is
only caused by scattered light. Colourants or colouring pigments do
not normally contribute to this colour effect. Only certain
additives, such as, for example, the nano-scale boride-based IR
absorbers, cause this effect. Furthermore, it must be pointed out
that the scattering effect is pronounced only under certain light
conditions and defined viewing angles. This is the case, for
example, when the article--preferably a panel--is viewed under good
light conditions, that is to say under solar radiation and at
observation angles of from 1 to 60.degree..
[0020] The bluish scattering is caused by the IR additive, which
consists of fine particles. These particles, which on average have
a size, which can be determined, for example, by means of TEM
(transmission electron microscopy), of preferably less than 200 nm,
particularly preferably less than 100 nm, cause a scattering effect
and can accordingly also lead to undesirable colour reflections. In
order to minimise that effect, attempts could be made to reduce the
diameter of the particles or to limit the amount of particles in
the matrix. However, this is complex because the particles must be
very finely ground and the risk of reagglomeration exists or, if
the particle concentration is too low, the desired effect can no
longer be achieved.
[0021] It is known that finely divided particles can cause
so-called Rayleigh scattering. This Rayleigh scattering is
described, for example, in C. F. Bohren, D. Huffmann, Absorption
and scattering of light by small particles, John Wiley, New York
1983. The scattering behaviour of boride-based nanoparticles has
not hitherto been described. The concentration ranges in which the
described colour scattering effects occur were likewise hitherto
not known. Measures for attenuating the described effect were not
obvious from the current prior art.
[0022] Further, thermoplastic moulding compositions are known which
contain both IR absorbers and colouring pigments, inter alia carbon
blacks, in order to influence both the heat-absorbing properties
and the colouration. However, measures for reducing the scattered
radiation caused by boride-based IR-absorbing particles are as
rarely described in the literature as that undesirable effect.
[0023] Compositions based on polycarbonate containing boride-based
inorganic IR absorbers have been described in various
publications.
[0024] DE 10392543 A1 describes transparent heat ray shielding
foils which contain fine particles of hexaboride. The present
invention, on the other hand, relates to compositions containing
specific combinations of inorganic IR absorbers and inorganic
pigment for reducing scattering effects.
[0025] US 2004/0028920 describes masterbatches containing
boride-based inorganic IR absorbers for the production of moulded
parts. US 2004/0028920 neither mentions scattering effects nor
describes compositions which would reduce this effect. The use of
carbon black is described in the general part of this application
only as an agent for adjusting the colour, that is to say as a
colouring agent.
[0026] EP 1 559 743 describes polymer compositions containing
inorganic IR absorbers in combination with organic UV absorbers.
However, this application does not describe the scattering effect
described in the present invention. EP 1 559 743 gives no
indication of how the scattering effect can be reduced.
[0027] Moulding compositions containing boride-based IR absorbers
and specific carbon blacks are known from WO 2007/008476 A1, a
synergistic effect in respect of the IR-absorbing properties being
said to be achieved by the combination of these components.
However, this application does not mention the effect described
herein and gives no indication of how the problem described in the
present application could be solved. WO 2007/008476 relates to
materials which are suitable in particular for spectacles. The
concentrations of colouring agents, inorganic IR absorbers and
nano-scale inorganic pigments used therein are, however, completely
different to those used in the present invention to solve the
described problem in glazing, such as automotive or architectural
glazing.
[0028] EP 1865027 A1 describes polymer compositions of specific
polycarbonates, which additionally contain lanthanum hexaboride as
IR absorber. EP 1865027 does not describe the problem described in
the present invention, nor can the person skilled in the art see
how the problem could be solved.
[0029] None of the above-mentioned documents describes scattering
or reflection effects of inorganic IR absorbers in transparent
thermoplastics and the problems resulting therefrom, and a solution
to this problem s accordingly not rendered obvious either.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 illustrates a measuring system for measuring
scattering effects.
BRIEF DESCRIPTION OF SOME EMBODIMENTS
[0031] The invention relates to a polymer composition which absorbs
infrared radiation (IR), containing a transparent thermoplastic
plastic, an inorganic infrared absorber, also referred to as IR
absorber hereinbelow, and at least one inorganic nano-scale
pigment, and to the preparation and use of the polymer compositions
according to the invention, and to products produced therefrom. In
particular, the present invention relates to the reduction of
undesirable scattering effects caused by boride-based inorganic IR
absorbers, and to the use of the polymer composition according to
the invention containing such IR absorbers in the production of
glazing for use in buildings, motor vehicles and railway vehicles
or aircraft.
[0032] An embodiment of the present invention is a composition
comprising [0033] a. at least one transparent thermoplastic
material; [0034] b. at least one inorganic IR absorber comprising
at least one boride compound present in an amount of from 0.00150
wt. % to 0.01500 wt. %, calculated as solids content of boride in
the total polymer composition; and [0035] c, at least one
inorganic, nano-scale pigment present in an amount of from 0.00080
wt. % to 0.00350 wt. %, based on the total composition; and [0036]
d. optionally further additives.
[0037] Another embodiment of the present invention is a masterbatch
comprising [0038] a. from 85.00 wt. % to 98.90 wt. % of a
transparent thermoplastic material; [0039] b. from 0.10 wt. % to
2.00 wt. % of a boride as inorganic IR absorber; and [0040] c. from
1.00 wt. % to 4.80 wt. % of a dispersing agent; [0041] d.
optionally from 0.00 wt. % to 0.20 wt. % of at least one stabilizer
selected from the group consisting of phosphines, phosphites and
phenolic antioxidants and mixtures thereof; [0042] e. optionally
from 0.001 wt. % to 0.200 wt. % of an inorganic nano-scale pigment;
[0043] f. optionally from 0.00 wt. % to 8.00 wt. % of at least one
further auxiliary substance and/or at least one additive,
[0044] wherein the sum of components a to f is 100 wt. %.
[0045] A still further embodiment of the present invention is a
method which comprises adding carbon black to a polymer composition
which comprises nano-scale particles wherein the scattering caused
by the nano-scale particles is reduced.
[0046] The object of the present invention was to provide
transparent polymer compositions having no or low haze, good IR
absorption and minimised colour effects by scattering, which
compositions do not exhibit the disadvantages of the compositions
known from the prior art.
[0047] It was a further object of the present invention to provide
such compositions in the form of a masterbatch for further
processing, as well as moulded parts produced using such
compositions.
[0048] In order to detect and measure the scattering effects, test
specimens are illuminated at an angle of incidence of 60.degree.
relative to the vertical using a white point light source with a
small opening angle of less than 2.degree. and the scattering is
measured at an emergent angle of from 30.degree. to -80.degree.
relative to the vertical (see FIG. 1). Furthermore, the CIELAB
colour coordinates L*, a*, b* are calculated in accordance with
ASTM E 308 using illuminant D65 and a 10.degree. observer. This
colour system is described, for example, in Manfred Richter:
Einfuhrung in die Farbmetrik. 1984 ISBN 3-11-008209-8. For the
evaluation of the colour, the b* value at an emergent angle of
-10.degree. is used. This b* value is referred to hereinbelow as
b*(60.degree.), the value of 60.degree. relating to the angle of
incidence.
[0049] The measurements were carried out using a "Gon360-105"
goniophotometer (Gon360 with multichannel spectrometer CAS 140)
from Instrument Systems. The measuring system is shown in FIG. 1,
where the reference numerals have the following meanings [0050] 1
sample, [0051] 2 white light source, [0052] 3 detector with colour
coordinate evaluation, [0053] 4 incident light at 60.degree.
relative to normal (perpendicular), [0054] 5 scattered and
reflected light, [0055] 6 angle range in which the detector
measures the colour, and [0056] 7 perpendicular direction of
arrival (normal direction).
[0057] In addition, the hemispherical reflection of the test
specimen is measured in accordance with ASTM E 1331, and the CIELAB
colour coordinates L*, a*, b* are calculated in accordance with
ASTM E 308 using illuminant D65 and a 10.degree. observer. The
corresponding b* value is denoted b*(hemispherical)
hereinbelow.
[0058] A measure of the extent of the scattering effect is
accordingly the measurement of the b* value in reflection
(b*(60.degree.)) at which the scattered light is measured. The
closer b*(60.degree.) to zero, the lower the reflection in the blue
range.
[0059] The b*(60.degree.) value of the reflected light at an
emergent angle of -10.degree. of the moulded bodies according to
the invention is preferably in the range from -2.5 to 0.0, more
preferably from -2.3 to 0.0.
[0060] The limit of -2.5 or -2.3 for b*(60.degree.) arises from the
requirement that as neutral grey a colour as possible is required
for automotive glazing, but the nanoparticles always cause a bluish
scattering.
[0061] The absolute value of the value .DELTA.b*, calculated from
the difference between b*(60.degree. and the hemispherical
reflection b*(hemispherical), which is less than 1.0 in the case of
moulded bodies according to the invention.
[0062] The limit of .DELTA.b*<1.0 is given by the colour
difference of delta E (calculated in accordance with DIN 6174)
detectable by the human eye, which is less than 1.0. Because this
scattering is substantially a bluish scattering, the calculation is
here simplified to the difference .DELTA.b*, which relates to the
blue component of the light.
[0063] When studying the scattering behaviour it was found that the
undesirable scattering effects are greatly dependent on the
concentration of boride-based IR absorber in the polymer
matrix.
[0064] Surprisingly, it has been shown that the increase in the
scattered radiation, measured as the b*(60.degree.) value, based on
the IR absorber concentration used, is not linear. Thus, in the
higher concentration range above 0.01000 wt. % (boride
concentration), the relative increase in the scattered radiation is
smaller than in the middle concentration range of from 0.00100 wt.
% to 0.00500 wt. %. Accordingly, a pronounced increase in the
scattered radiation is to be observed in the range from 0.00100 wt.
% to 0.00500 wt. %, while the increase, surprisingly, diminishes at
concentrations above 0.01000 wt. %.
[0065] Accordingly, the object of the present invention is achieved
by compositions containing boride in a concentration range from
0.00150 wt. % to 0.01500 wt. %, in which the relative increase in
the scattered radiation, measured as b*(60.degree.), increases
sharply with the boride concentration, in conjunction with an
inorganic nano-scale pigment, preferably a nano-scale carbon
black.
[0066] Surprisingly, it has been shown that certain inorganic
nano-scale pigments reduce the undesirable scattering effect
without markedly affecting the transparency and without changing
the overall colour impression in a negative manner (neutral colour
impression).
[0067] Other pigments and colourants, on the other hand, are less
effective or ineffective or distort the original colour impression
or, like organic colouring agents, are not stable in the long term
and can thus lead to undesirable colour effects. Moreover, the
additional use of colouring agents is expensive and accordingly not
economical.
[0068] It has been found that certain carbon blacks in particular,
preferably nano-scale carbon blacks, markedly reduce the described
phenomenon of bluish scattering in specific concentration ranges.
It was particularly surprising that even relatively low
concentrations in the range of from 0.00080 wt. % to 0.00350 wt. %
are sufficient to reduce the scattering effect significantly.
[0069] It was also surprising that only specific ratios of
nano-scale carbon black to boride-based IR-absorbing additive
reduce the scattering effect. Too high concentrations of carbon
black drastically reduce the transmission (<6%) and change the
inherent colour of the composition, while too low a concentration
of carbon black has only an inadequate effect. The same is true of
the concentration of boride-based IR absorbers.
[0070] Surprisingly, it has accordingly been found that the
undesirable colour effects caused by scattering can be prevented or
at least significantly reduced without impairing other physical
properties such as transmission and haze only within a narrowly
defined concentration range both of IR absorber and of nano-scale
carbon black, or with a defined ratio of those components to one
another.
[0071] Accordingly, the problem underlying the present invention is
solved by compositions according to claim 1 based on thermoplastic
materials containing defined concentrations of boride-based IR
absorbers as well as specific concentrations of specific inorganic,
preferably nano-scale, pigments. By means of those compositions,
the bluish-violet colour caused by scattering could be reduced or
changed to a more neutral colouration.
[0072] Further colouring agents are preferably used in the polymer
compositions according to the invention, more preferably colouring
agents based on anthraquinone, perinone or phthaloperinone, because
glazing with a particular colouration is desirable especially in
the automotive sector. It has been shown that the above-described
scattering effect also occurs in such coloured polymer compositions
when boride-based inorganic IR absorbers are added. Surprisingly,
the scattering effect could be limited in such coloured
compositions too by the use of specific concentrations of inorganic
pigments.
[0073] The polymer compositions according to the invention
contain:
[0074] a) a transparent thermoplastic plastic, preferably
polycarbonate, copolycarbonate, polystyrene, styrene copolymers,
aromatic polyesters such as polyethylene terephthalate (PET),
PET-cyclohexanedimethanol copolymer (PETG), polyethylene
naphthalate (PEN), polybutylene terephthalate (PBT), cyclic
polyolefin, poly- or copoly-methyl methacrylates such as polymethyl
methacrylate, thermoplastic polyurethanes, more preferably
polycarbonate, copolycarbonate, aromatic polyesters or polymethyl
methacrylate, or mixtures of the mentioned components, and
particularly preferably polycarbonate and copolycarbonate,
[0075] b) an inorganic IR absorber from the group of the boride
compounds of type MxBy (M=La, Ce, Pr, Nd, Tb, Dy, Ho, Y, Sm, Eu,
ER, Tin, Yb, Lu, Sr, Ti, Zr, Hf, V, Ta, Cr, Mo, W and Ca,
preference being given to lanthanum hexaboride (LaB.sub.6),
praseodymium boride (PrB.sub.6), neodymium boride (NdB.sub.6),
cerium boride (CeB.sub.6), terbium boride (TbB.sub.6), dysprosium
boride (DyB.sub.6), holmium boride (HoB.sub.6), yttrium boride
(YB.sub.6), samarium boride (SmB.sub.6), europium boride
(EuB.sub.6), erbium boride (ErB.sub.6), thulium boride (TmB.sub.6),
ytterbium boride (YbB.sub.6), lutetium boride (LuB.sub.6),
strontium boride (SrB.sub.6), calcium boride (CaB.sub.6), titanium
boride (TiB.sub.2), zirconium boride (ZrB.sub.2), hafnium boride
(HfB.sub.2), vanadium boride (VB.sub.2), tantalum boride
(TaB.sub.2), chromium boride (CrB and CrB.sub.2), molybdenum boride
(MoB.sub.2, Mo.sub.2B.sub.5 and MoB), tungsten boride
(W.sub.2B.sub.5), or combinations of these borides. Borides based
on lanthanum hexaboride (LaB.sub.6) or mixtures containing
lanthanum hexaboride are most particularly preferred.
[0076] The borides are preferably used in an amount of from 0.00150
wt. % to 0.01500 wt. %, preferably from 0.00200 wt. % to 0.01100
wt. % and particularly preferably from 0.00270 wt. % to 0.00800 wt.
%, calculated as solids content of boride in the total polymer
composition. In a particular embodiment, which can contain further
colouring agents, the borides are used in an amount of preferably
from 0.00350 wt. % to 0.00850 wt. % and particularly preferably
from 0.00400 wt. % to 0.00800 wt. %, calculated as solids content
of boride in the total polymer mixture. In this connection, solids
content of boride means the boride in the form of the pure
substance and not a suspension or other preparation containing the
pure substance.
[0077] c) at least one inorganic, nano-scale pigment, preferably
carbon black, in particular nano-scale carbon black.
[0078] The nano-scale carbon black is used in the composition
according to the invention preferably in concentrations of from
0.00080 wt. % to 0.00350 wt. %, particularly preferably from
0.00090 wt. % to 0.00300 wt. % and most particularly preferably in
concentrations of from 0.00100 wt. % to 0.00280 wt. %. In a
particular embodiment, which can contain further colouring agents,
the nano-scale carbon black is preferably used in an amount of from
0.00140 wt. % to 0.00260 wt. %, particularly preferably in an
amount of from 0.00150 wt. % to 0.00250 wt. %.
[0079] d) optionally at least one colouring agent based on
anthraquinone, perinone or phthaloperinone, or mixtures thereof,
and
[0080] e) optionally additives, such as stabilizers, antioxidants,
demoulding agents, flameproofing agents, heat stabilizers, UV
stabilizers, or optical brightening agents.
[0081] The invention further provides a process for the preparation
of the compositions according to the invention and the use thereof
and products produced therefrom.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
[0082] Transparent thermoplastic plastics within the scope of the
invention are, for example, polymers of ethylenically unsaturated
monomers and/or polycondensation products of bifunctional reactive
compounds. Examples of transparent thermoplastic polymers are, for
example, polycarbonates or copolycarbonates based on diphenols,
poly- or copoly-acrylates and poly- or copoly-methacrylate, such
as, for example, poly- or copoly-methyl methacrylates (such as
PMMA), as well as copolymers with styrene, such as, for example,
transparent polystyrene acrylonitrile (PSAN), or polymers based on
ethylene and/or propylene as well as aromatic polyesters such as
polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
polyethylene naphthalate (PEN) or polyethylene
terephthalate-cyclohexanedimethanol copolymer (PETG), transparent
thermoplastic polyurethanes and polystyrenes. Polymers based on
cyclic olefins (e.g. TOPAS.RTM., a commercial product of Ticona)
can also be mixed in.
[0083] Mixtures of a plurality of transparent thermoplastic
polymers, in so far as they can be mixed with one another to give a
transparent mixture, are also possible, preference being given to a
mixture of polycarbonate with PMMA (more preferably with PMMA<2
wt. %) or polyester.
[0084] Particularly preferred polycarbonates are the
homopolycarbonate based on bisphenol A, the homopolycarbonate based
on 1,3-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and the
copolycarbonates based on the two monomers bisphenol A and
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
[0085] Polycarbonates within the scope of the present invention are
both homopolycarbonates and copolycarbonates; the polycarbonates
can, in known manner, be linear or branched.
[0086] The preparation of the polycarbonates is carried out in
known manner from diphenols, carbonic acid derivatives, optionally
chain terminators and branching agents.
[0087] Details of the preparation of polycarbonates have been laid
down in many patent specifications for about 40 years. By way of
example, reference is made here only to Schnell, "Chemistry and
Physics of Polycarbonates", Polymer Reviews. Volume 9. Interscience
Publishers, New York, London, Sydney 1964, to D. Freitag, U. Grigo,
P. R. Muller, H. Nouvertne', BAYER AG, "Polycarbonates" in
Encyclopedia of Polymer Science and Engineering. Volume 11, Second
Edition, 1988, pages 648-718, and finally to Dres. U. Grigo, K.
Kirchner and P. R. Muller "Polycarbonate" in Becker/Braun,
Kunststoff-Handbuch. Volume 3/1, Polycarbonate, Polyacetate,
Polyester, Celluloseester, Carl Hanser Verlag Munich. Vienna 1992,
pages 117-299.
[0088] Diphenols suitable for the preparation of the polycarbonates
are, for example, hydroquinone, resorcinol, dihydroxydiphenyls,
bis-(hydroxyphenyl)-alkanes, bis(hydroxyphenyl)-cycloalkanes,
bis-(hydroxyphenyl)sulfides, bis-(hydroxyphenyl)ethers,
bis-(hydroxyphenyl)ketones, bis-(hydroxyphenyl)-sulfones,
bis-(hydroxyphenyl)sulfoxides,
alpha,alpha'-bis-(hydroxyphenyl)-diisopropylbenzenes, pththalimides
derived from isatin or phenolphthalein derivatives, and compounds
thereof alkylated and halogenated on the ring.
[0089] Preferred diphenols are 4,4'-dihydroxydiphenyl,
2,2-bis-(4-hydroxyphenyl)-propane,
2,4-bis-(4-hydroxyphenyl)-2-methylbutane,
1,1-bis-(4-hydroxyphenyl)-p-diisopropylbenzene,
2,2-bis-(3-methyl-4-hydroxyphenyl)-propane,
2,2-bis-(3-chloro-4-hydroxyphenyl)-propane,
bis-(3,5-dimethyl-4-hydroxyphenyl)-methane,
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane,
bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfone,
2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane,
1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene,
2,2-bis-(3,5-dichloro-4-hydroxy-phenyl)-propane,
2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane and
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
[0090] Particularly preferred diphenols are
2,2-bis-(4-hydroxyphenyl)-propane,
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane,
2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane,
2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane,
1,1-bis-(4-hydroxyphenyl)-cyclohexane and
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
[0091] These and further suitable diphenols are described, for
example, in U.S. Pat. No. 3,028,635, U.S. Pat. No. 2,999,825, U.S.
Pat. No. 3,148,172, U.S. Pat. No. 2,991,273, U.S. Pat. No.
3,271,367, U.S. Pat. No. 4,982,014 and U.S. Pat. No. 2,999,846, in
DE-A 1 570 703, DE-A 2 063 050, DE-A 2 036 052, DE-A 2 211 956 and
DE-A 3 832 396, in FR-A 1 561 518, in the monograph "H. Schnell,
Chemistry and Physics of Polycarbonates, Interscience Publishers,
New York 1964" and in JP-A 62039/1986, JP-A 62040/1986 and JP-A
105550/1986.
[0092] In the case of homopolycarbonates, only one diphenol is
used; in the case of copolycarbonates, a plurality of diphenols is
used.
[0093] Suitable carbonic acid derivatives are, for example,
phosgene or diphenyl carbonate.
[0094] Suitable chain terminators which can be used in the
preparation of the polycarbonates are both monophenols and
monocarboxylic acids. Suitable monophenols are phenol itself,
alkylphenols such as cresols, p-tert-butylphenol, cumylphenol,
p-n-octylphenol, p-isooctylphenol, p-n-nonylphenol and
p-isononylphenol, halophenols such as p-chlorophenol,
2,4-dichlorophenol, p-bromophenol and 2,4,6-tribromophenol,
2,4,6-triiodophenol, p-iodophenol, and mixtures thereof.
[0095] Preferred chain terminators are phenol, cumylphenol and/or
p-tert-butylphenol.
[0096] Suitable monocarboxylic acids are also benzoic acid,
alkylbenzoic acids and halobenzoic acids.
[0097] Preferred chain terminators are also the phenols which are
mono- or poly-substituted by C1- to C30-alkyl radicals, linear or
branched, preferably unsubstituted or substituted by
tert-butyl.
[0098] The amount of chain terminator to be used is preferably from
0.1 to 5 mol %, based on moles of diphenols used in a particular
case. The addition of the chain terminators can take place before,
during or after the phosgenation.
[0099] Suitable branching agents are the compounds known in
polycarbonate chemistry having a functionality of three or more
than three, in particular those having three or more than three
phenolic OH groups.
[0100] Suitable branching agents are, for example, phloroglucinol,
4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-hept-2-ene,
4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)-heptane,
1,3,5-tri(4-hydroxyphenyl)-benzene,
1,1,1-tri-(4-hydroxyphenyl)-ethane,
tri-(4-hydroxyphenyl)-phenylmethane,
2,2-bis-[4,4-bis-(4-hydroxyphenyl)-cyclohexyl]-propane,
2,4-bis-(4-hydroxyphenylisopropyl)-phenol,
2,6-bis-(2-hydroxy-5'-methyl-benzyl)-4-methylphenol,
2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)-propane,
hexa-(4(4-hydroxyphenyl isopropyl)-phenyl)-orthoterephthalic acid
ester, tetra-(4-hydroxyphenyl)-methane,
tetra-(4-(4-hydroxyphenylisopropyl)-phenoxy)-methane and
1,4-bis-((4',4''-dihydroxytriphenyl)-methyl)-benzene as well as
2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and
3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole.
[0101] The amount of branching agents optionally to be used is
preferably from 0.05 mol % to 2.00 mol %, based in turn on moles of
diphenols used in a particular case.
[0102] The branching agents can either be placed in the aqueous
alkaline phase with the diphenols and the chain terminators or they
can be dissolved in an organic solvent and added before the
phosgenation. In the case of the transesterification process, the
branching agents are used together with the diphenols.
[0103] The aromatic polycarbonates of the present invention have
weight-average molecular weights Mw (determined by gel permeation
chromatography and calibration with polycarbonate calibration) of
from 5000 to 200,000, preferably from 10,000 to 80,000 and
particularly preferably from 15,000 to 40,000 (this corresponds
approximately to from 12,000 to 330,000, preferably from 20,000 to
135,000 and particularly preferably from 28,000 to 69,000,
determined by calibration by means of polycarbonate standard).
[0104] The polymer compositions according to the invention can
optionally contain, in addition to the stabilizers according to the
invention, also further conventional polymer additives, such as,
for example, the antioxidants, demoulding agents, flameproofing
agents, colouring agents, heat stabilizers, UV stabilizers or
optical brightening agents described in EP-A 0 839 623, WO-A
96/15102, EP-A 0 500 496 or "Plastics Additives Handbook", Hans
Zweifel, 5th Edition 2000, Hanser Verlag Munich, in the amounts
conventional for the thermoplastics in question. In a specific
embodiment of the invention, of the mentioned further conventional
polymer additives that are optionally present, particular
preference is given to colouring agents. The further polymer
additives are preferably used in amounts of from 0 wt. % to 5 wt.
%, more preferably from 0.1 wt. % to 1 wt %, in each case based on
the amount of the total polymer compositions. Mixtures of a
plurality of additives are also possible.
[0105] The nano-scale boride-based inorganic IR absorber particles
provided by the present application are preferably a metal boride,
the metal being selected from the group comprising La, Ce, Pr, Nd,
Tb, Dy, Ho, Y, Sm, Eu, ER, Tm, Yb, Lu, Sr, Ti, Zr, Hf, V, Ta, Cr,
Mo, W and Ca. The hexaboride form is particularly preferred.
Particular preference is given to lanthanum hexaboride (LaB.sub.6),
praseodymium boride (PrB.sub.6), neodymium boride (NdB.sub.6),
cerium boride (CeB.sub.6), terbium boride (TbB.sub.6), dysprosium
boride (DyB.sub.6), holmium boride (HoB.sub.6), yttrium boride
(YB.sub.6), samarium boride (SmB.sub.6), europium boride
(EuB.sub.6), erbium boride (ErB.sub.6), thulium boride (TmB.sub.6),
ytterbium boride (YbB.sub.6), lutetium boride (LuB.sub.6),
strontium boride (SrB.sub.6), calcium boride (CaB.sub.6), titanium
boride (TiB.sub.2), zirconium boride (ZrB.sub.2), hafnium boride
(HfB.sub.2), vanadium boride (VB.sub.2), tantalum boride
(TaB.sub.2), chromium boride (CrB and CrB.sub.2), molybdenum boride
(MoB.sub.2, Mo.sub.2B.sub.5 and MoB), tungsten boride
(W.sub.2B.sub.5), or combinations of these borides. Most particular
preference is given to borides based on lanthanum hexaboride
(LaB.sub.6) or mixtures containing lanthanum hexaboride.
[0106] The surface of these particles is preferably unoxidised;
however, oxidised or partially oxidised particles can be used.
[0107] In a particular embodiment of the present invention, the use
solely of lanthanum hexaboride (LaB.sub.6) is most particularly
preferred.
[0108] The boride-based IR absorbers can be prepared, for example,
from oxides of the rare earths, such as, for example,
X.sub.2O.sub.3 (where X e.g. =La, Ce, Pr, Nd, Gd) and, for example,
boron carbides (B4C) by mixing those compounds and tempering the
mixture for several hours, such as, for example, 3 hours, in vacuo
at high temperatures, such as, for example 1500.degree. C. The
boride is obtained in the form of a powder. There is no limitation
regarding the form of the finely divided particles--for example,
the particles can have a spherical, platelet-like, irregular or
needle-like form. The absorbing power for IR radiation is greater,
the more crystalline the boride particles. However, even particles
having low crystallinity (e.g. characterised by a broad diffraction
peak in the X-ray diffraction experiment) have an adequate
IR-absorbing property within the scope of the invention. However,
that is only the case as long as the particles have on the inside a
bond of the metal used and boron. The colour of the particles in
the powder can be, for example, greyish-black, brownish-black,
greenish-black or the like.
[0109] The average size of the particles (determined by
TEM/transmission electron microscopy) is preferably smaller than
200 nm, particularly preferably smaller than or equal to 150 nm and
most particularly preferably smaller than 100 nm, the particle
diameters preferably being greater than 5 nm, more preferably
greater than 10 nm and particularly preferably greater than 15
nm.
[0110] There are no limitations regarding the size distribution of
the particles, so bi- or higher-modal distributions can also be
present. The particles are transparent in the visible range of the
spectrum, transparent meaning that the absorption of the IR
absorbers in the visible range is low compared with the absorption
in the IR range and the IR absorber does not lead to markedly
increased haze of the composition or the end product in question.
This means that, in the composition as a whole, the transparent
moulded body has a transmission of at least 6% and a haze of less
than 3%, preferably less than 2.5%, more preferably less than 2.0%.
The Tds value is preferably less than 70%, particularly preferably
less than 60% and most particularly preferably less than 50%. In a
particular embodiment, the Tds value is less than 20%, particularly
preferably less than 15% (T.sub.ds; direct solar transmittance;
values are measured on optical colour sample sheets having a
thickness of 4 mm. Calculation of the total transmission T.sub.ds
is carried out in accordance with ISO 13837, computational
convention "A").
[0111] The size of the particles can be determined by means of
transmission electron microscopy (TEM). Such measurements on IR
absorber nanoparticles are described, for example, in Adachi et
al., J. Am. Ceram. Soc. 2008, 91, 2897-2902.
[0112] The surface of the particles can be treated. For example,
the surface can be treated with a silane or provided with a
titanium-based or zirconium-based layer or similar layers. The
resistance to moisture can be increased by means of this treatment.
This type of coating increases the long-term stability in respect
of the IR absorption and is described, for example, in US 2005
0161642.
[0113] In addition to the boride-based particles, further particles
based on SiO.sub.2, TiO.sub.2, ZrO.sub.2, Al.sub.2O.sub.3 or MgO
can--but do not necessarily have to be--present. These particles
are preferably present in a size of less than 200 nm.
[0114] In the present invention, the finely divided IR absorber
particles are introduced into the polymer matrix in the form of a
dispersion. This dispersion prevents reagglomeration and
facilitates incorporation into a thermoplastic matrix such as, for
example, polycarbonate. Polymer-like dispersing agents are
preferably used. Suitable polymer-based dispersing agents are
especially dispersing agents which have high light transmission,
such as, for example, polyacrylates, polyurethanes, polyethers,
polyesters or polyurethanes and polymers derived therefrom.
Preferred as dispersing agents are polyacrylates, polyethers and
polyester-based polymers. Dispersing agents having high temperature
stability are preferably used.
[0115] The blend ratio of polymeric dispersing agent to boride
particles is usually from 0.2 wt. % to 50.0 wt. %, preferably from
0.5 wt. % to 50.0 wt. % and most particularly preferably from 1.0
wt. % to 40.0 wt. %, based on the amount by weight of inorganic IR
absorber. In order to prepare the inorganic IR absorber
nanoparticles according to the invention, the IR absorber can be
mixed with the dispersing agents described hereinbelow and further
organic solvents, such as, for example, toluene, benzene or similar
aromatic hydrocarbons, and ground in suitable mills, such as, for
example, ball mills, with the addition of zirconium oxide (e.g.
having a diameter of 0.3 mm) in order to prepare the desired
particle size distribution. The nanoparticles are obtained in the
form of a dispersion. After grinding, further dispersing agents can
optionally be added. The solvent is removed at elevated
temperatures and reduced pressure.
[0116] The preparation of lanthanum hexaboride and of the lanthanum
hexaboride dispersion is described, for example, in JP2003-277045,
DE 10392543 and in Adachi et al., J. Am. Chem. Ceram. Soc. 2008,
91[9], 2897-2902. Lanthanum hexaboride in the form of the
dispersion, which is suitable within the scope of the invention, is
obtainable commercially from, for example, Sumitomo Metal Mining
Co., Ltd., for example under the trade name KHDS 06.
[0117] Dispersing agents suitable for the present invention are
obtainable commercially. Polyacrylate-based dispersing agents are
particularly suitable, Polyacrylates are obtainable, for example,
from Ciba Specialty Chemicals under the trade names EFKA.RTM., for
example EFKA.RTM. 4500 and EFKA.RTM. 4530. Polyester-based
dispersing agents are likewise suitable. Polyester-containing
dispersing agents are obtainable from Avecia under the trade names
Solsperse.RTM., for example Solsperse.RTM. 22000, 24000SC, 26000,
27000, Polyurethane-based systems are also suitable. These are
obtainable from Ciba Specialty Chemicals under the trade names
EFKA.RTM. 4046, EFKA.RTM. 4047. Texaphor.RTM. P60 and P63 are
corresponding trade names of Cognis. Polyether-containing
dispersing agents can likewise be used. These are known, for
example, under the trade names Disparlon.RTM. DA234 and DA325 of
Kusumoto Chemicals.
[0118] The dispersing agents can be used on their own or in
combinations. With regard to the thermal stability, dispersing
agents from the group of the polyacrylates and polyesters are
particularly preferred.
[0119] The IR-absorbing inorganic boride is preferably used in the
polymer composition according to the invention in dispersion in an
organic matrix and preferably in the concentrations described
below. Preferably, the borides are used in an amount of from
0.00150 wt. % to 0.01500 wt. %, preferably from 0.00200 wt. % to
0.01100 wt. % and particularly preferably from 0.00270 wt. % to
0.00800 wt. %, calculated as solids content of boride in the total
polymer composition. In a particular embodiment, which can contain
further colouring agents, the borides are used in an amount of
preferably from 0.00350 wt. % to 0.00850 wt. % and particularly
preferably from 0.00400 wt. % to 0.00800 wt. %, calculated as
solids content of boride in the total polymer composition. In this
connection, solids content of boride means the boride in the form
of the pure substance and not a suspension or other preparation
containing the pure substance.
[0120] In a preferred embodiment, the lanthanum hexaboride is in
the form of a ready-to-use dispersion of a mixture of polymethyl
methacrylate and polyester in a solids content of from 5 wt. % to
25 wt. %. Organic solvents such as toluene and further inorganic
particles such as zirconium dioxide can additionally be
present.
[0121] In a further embodiment it is possible additionally to use
further IR absorbers as IR absorbers in addition to the borides
according to the invention, the amount of such further IR absorbers
as regards amount and/or performance in such a mixture in each case
being below the amount of the above-described borides. In the case
of mixtures, preference is given to compositions that contain from
two up to and including five and particularly preferably two or
three different IR absorbers. In a particular embodiment of the
present invention, the polymer-composition according to the
invention does not contain any inorganic IR absorbers of the
tungstate type, such as, for example, caesium tungstate,
Cs.sub.0.33 WO.sub.3.
[0122] The further IR absorber is preferably selected from the
group of the tin oxides, particularly preferably antimony-doped tin
oxide or indium tin oxide.
[0123] Compounds such as indium oxide doped with from 2 to 30 atom
%, preferably from 4 to 12 atom %, tin (ITO) or with from 10 to 70
atom % fluorine can further be added.
[0124] Particular preference is given to the combination with tin
oxide as a further IR absorber, which tin oxide is doped with from
2 to 60 atom % antimony (ATO) or with from 10 to 70 atom %
fluorine.
[0125] Zinc oxide doped with from 1 to 30 atom %, preferably from 2
to 10 atom %, aluminium or with from 2 to 30 atom % indium or with
from 2 to 30 atom % gallium is further preferred.
[0126] Mixtures of the above-mentioned infrared absorbers are
particularly suitable because the person skilled in the art, by
means of a suitable choice, can optimise the absorption in the
near-infrared range.
[0127] In a further preferred embodiment, the additional IR
absorber(s) has (have) an absorption spectrum different from that
of the boride used based on the absorption maxima, so that a
maximum absorption range is covered by the maxima.
[0128] Suitable additional organic infrared absorbers are described
by substance classes in, for example, M. Matsuoka, Infrared
Absorbing Dyes, Plenum Press, New York, 1990. Particularly suitable
are infrared absorbers from the classes of the phthalocyanines, the
naphthalocyanines, the metal complexes, the azo dyes, the
anthraquinones, the quadratic acid derivatives, the immonium dyes,
the perylenes, the quaterylenes and the polymethines. Of those,
phthalocyanines and naphthalocyanines are most particularly
suitable.
[0129] On account of their improved solubility in thermoplastics,
phthalocyanines and naphthalocyanines having sterically demanding
side groups are to be preferred, such as, for example, phenyl,
phenoxy, alkylphenyl, alkylphenoxy, tert-butyl, (--S-phenyl),
--NH-aryl, --NH-alkyl and similar groups.
[0130] The polymer composition contains at least one inorganic
pigment, preferably carbon black. The carbon black is preferably
present in finely dispersed form in the organic polymer matrix and
is preferably nano-scale. Suitable carbon blacks have an average
particle size of preferably less than 100 nanometres (nm), more
preferably less than 75 nm, yet more preferably less than 50 nm and
particularly preferably less than 40 nm, the average particle size
preferably being greater than 0.5 nm, more preferably greater than
1 nm and particularly preferably greater than 5 nm.
[0131] Carbon blacks suitable within the scope of the invention
differ from so-called conductive blacks in that they have only low
or no electrical conductivity. Compared with the carbon blacks used
here, conductive blacks have specific morphologies and
superlattices in order to achieve high conductivity. By contrast,
the nano-scale carbon blacks used here can very readily be
dispersed in thermoplastics so that virtually no cohesive regions
of carbon black occur, from which a corresponding conductivity
might result. Suitable carbon blacks within the scope of the
invention which are obtainable commercially are obtainable under a
large number of trade names and in a large number of forms, such as
pellets or powder. For example, suitable carbon blacks are
obtainable under the trade names BLACK PEARLS.RTM., in the form of
wet-processed pellets under the names ELFTEX.RTM., REGAL.RTM. and
CSX.RTM., and in a flocculent form under the names MONARCH.RTM.,
ELFTEX.RTM., REGAL.RTM. and MOGUL.RTM.--all obtainable from Cabot
Corporation.
[0132] In a particularly preferred embodiment, the carbon black
types have particle sizes of from 10 to 30 nm and have a surface
area of preferably from 35 to 138 m.sup.2 per g (m.sup.2/g). The
carbon black can be treated or untreated--for example, the carbon
black can be treated with specific gases, with silica or organic
substances, such as, for example, butyllithium. Such treatment
allows the surface to be modified or functionalised. This can
promote compatibility with the correspondingly used matrix.
Particular preference is given to carbon blacks marketed under the
trade name BLACK PEARLS.RTM. (CAS No. 1333-86-4).
[0133] The nano-scale carbon black is used in the composition
according to the invention preferably in concentrations of from
0.00080 wt. % to 0.00350 wt. %, particularly preferably from
0.00090 wt. % to 0.00300 wt. % and most particularly preferably in
concentrations of from 0.00100 wt. % to 0.00280 wt. %. In a
particular embodiment, which can contain further colouring agents,
the nano-scale carbon black is preferably used in an amount of from
0.00140 wt. % to 0.00260 wt. %, particularly preferably in an
amount of from 0.00150 wt. % to 0.00250 wt. %.
[0134] In a preferred embodiment, the ratio of IR absorber to
carbon black is from 20:1 to 0.4:1, preferably from 15:1 to 1:1. In
a specific embodiment of the present invention, the ratio of IR
absorber to carbon black is from 5:1 to 1.5:1.
[0135] The concentrations indicated herein for carbon blacks and IR
absorbers are preferably used for finished parts having thicknesses
of from 2 mm to 8 mm, preferably from 3.5 to 7.0 mm and
particularly preferably from 4 mm to 6 mm. In the case of a smaller
or larger thickness, the concentrations must be increased or
reduced accordingly in order to avoid, for example, too great a
haze or too low an effect.
[0136] In a particular embodiment in which, for example, high
torsional stiffness is required--for example in the case of
aircraft/railway vehicles--thicknesses of from 8 to 20 mm can be
required. The concentrations of the IR absorbers and of the
inorganic nano-scale pigment must be adapted accordingly in this
case, that is to say the concentration falls as the layer thickness
increases.
[0137] In a particular embodiment, the polymer composition contains
heat stabilizers. Particularly suitable are phosphites and
phosphonites as well as phosphines. Examples are biphenyl
phosphite, diphenylalkyl phosphite, phenyldialkyl phosphite,
tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl
phosphite, distearylpentaerythritol diphosphite,
tris(2,4-di-tert-butylphenyl)phosphite, diisodecylpentaerythritol
diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol
diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite,
bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite,
diisodecyloxypentaerythritol diphosphite,
bis(2,4-di-tert-butyl-6-methylphenyl)-pentaerythritol diphosphite,
bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite,
tristearylsorbitol triphosphite,
tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite,
6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosph-
ocine, bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,
bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,
6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosp-
hocine,
2,2',2''-nitrilo-[triethyltris(3,3',5,5'-tetra-tert-butyl-1,1'-bip-
henyl-2,2'-diyl)phosphite],
2-ethylhexyl(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl)phosphite-
,
5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane,
triphenylphosphine (TPP), trialkylphenylphosphine,
bisdiphenylphosphino-ethane or a trinaphthylphosphine. Particular
preference is given to the use of triphenylphosphine (TPP),
Irgafos.RTM. 168 (tris(2,4-di-tert-butyl-phenyl)phosphite) and
tris-(nonylphenyl)phosphite or mixtures thereof.
[0138] Phenolic antioxidants such as alkylated monophenols,
alkylated thioalkylphenols, hydroquinones and alkylated
hydroquinones can also be used. Irganox.RTM. 1010 (pentaerythritol
3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate; CAS: 6683-19-8)
and Irganox.RTM. 1076
(2,6-di-tert-butyl-4-(octadecanoxycarbonylethyl)phenol) are
preferably used. In a specific embodiment of the present invention,
the phosphine compounds according to the invention are used
together with a phosphite or a phenolic antioxidant or a mixture of
the two last-mentioned compounds.
[0139] In a preferred embodiment, the polymer composition according
to the invention further contains an ultraviolet absorber.
Ultraviolet absorbers suitable for use in the polymer composition
according to the invention are compounds that have as low a
transmission as possible below 400 nm and as high a transmission as
possible above 400 nm. Such compounds and their preparation are
known in the literature and are described, for example, in EP-A 0
839 623, WO-A 96/15102 and EP-A 0 500 496. Particularly suitable
ultraviolet absorbers for use in the composition according to the
invention are benzotriazoles, triazines, benzophenones and/or
arylated cyanoacrylates.
[0140] Particularly suitable ultraviolet absorbers are
hydroxy-benzotriazoles, such as
2-(3',5'-bis-(1,1-dimethylbenzyl)-2'-hydroxy-phenyl)-benzotriazole
(Tinuvin.RTM. 234, Ciba Spezialitatenchemie, Basel),
2-(2'-hydroxy-5'-(tert-octyl)-phenyl)-benzotriazole (Tinuvin.RTM.
329, Ciba Spezialitatenchemie, Basel),
2-(2'-hydroxy-3'-(2-butyl)-5'-(tert-butyl)-phenyl)-benzotriazole
(Tinuvin.RTM. 350, Ciba Spezialitatenchemie, Basel),
bis-(3-(2H-benztriazolyl)-2-hydroxy-5-tert-octyl)methane
(Tinuvin.RTM. 360, Ciba Spezialitatenchemie, Basel),
(2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)-phenol
(Tinuvin.RTM. 1577, Ciba Spezialitatenchemie, Basel), as well as
the benzophenones 2,4-dihydroxy-benzophenone (Chimasorb.RTM. 22,
Ciba Spezialitatenchemie, Basel) and
2-hydroxy-4-(octyloxy)-benzophenone (Chimassorb.RTM. 81, Ciba,
Basel), 2-propenoic acid,
2-cyano-3,3-diphenyl-2,2-bis[[(2-cyano-1-oxo-3,3-diphenyl-2-propenyl)oxy]-
-methyl]-1,3-propane-diyl ester (9C1) (Uvinul.RTM. 3030, BASF AG
Ludwigshafen),
2-[2-hydroxy-4-(2-ethylhexyl)oxy]phenyl-4,6-di(4-phenyl)phenyl-1,3,5-tria-
zine (CGX UVA 006, Ciba Spezialitatenchemie, Basel) or
tetra-ethyl-2,2'-(1,4-phenylene-dimethylidene)-bismalonate
(Hostavin.RTM. B-Cap, Clariant AG).
[0141] Mixtures of these ultraviolet absorbers can also be
used.
[0142] There are no particular limitations regarding the amount of
ultraviolet absorber contained in the composition, as long as the
desired absorption of UV radiation and adequate transparency of the
moulded body produced from the composition are ensured. According
to a specific embodiment of the invention, the composition contains
ultraviolet absorber in an amount of from 0.05 wt. % to 20.00 wt.
%, in particular from 0.07 wt. % to 10.00 wt. % and most
particularly preferably from 0.10 wt. % to 1.00 wt. %.
[0143] As well as containing the inorganic IR absorber and the
inorganic nano-scale pigment, the compositions according to the
invention preferably contain further colouring agents for adjusting
the colour. The colourants serve to adjust the colour in
transmission--they affect the reflected colour to only a minor
extent. They are preferably colouring agents based on
anthraquinone, on perinone or on phthaloperinone.
[0144] There is preferably used at least one colouring agent of the
following structures (1)-(2):
##STR00001##
[0145] In that formula, R1 can be a linear or branched alkyl
radical or halogen, preferably a halogen. n is a natural number
from 0 to 4.
##STR00002##
[0146] wherein the substituents R1, independently of one another,
can be the radicals described above and n for each designated
aromatic ring represents a natural number from 0 to 3.
[0147] The colourants of formulae (1) and (2) are preferably used
in amounts of from 0.00010 wt. % to 0.05000 wt. %, particularly
preferably from 0.00100 wt. % to 0.01000 wt. %, in each case based
on the total moulding composition.
[0148] As further additional colourants or pigments there can be
used, for example, organic or inorganic pigments or organic
colourants or the like. There can be used as inorganic pigments,
for example, sulfur-containing pigments such as cadmium red and
cadmium yellow, pigments based on iron cyanide such as Prussian
blue, oxide pigments such as titanium dioxide, zinc oxide, red iron
oxide, black iron oxide, chromium oxide, titanium yellow, zinc iron
brown, titanium cobalt green, cobalt blue, copper chromium black
and copper iron black or chromium-based pigments such as chromium
yellow. Preferred organic pigments or colourants are, for example,
colourants derived from phthalocyanine, such as copper
phthalocyanine blue and copper phthalocyanine green, condensed
polycyclic colourants and pigments, such as azo-based (e.g. nickel
azo yellow), sulfur indigo colourants, perynon-based,
perylene-based, quinacridone-derived, dioxazine-based,
isoindolinone-based and quinophthalone-derived derivatives,
anthraquinone-based, heterocyclic systems, etc. Of these, cyanine
derivatives, quinoline derivatives, anthraquinone derivatives,
phthalocyanine derivatives are preferred. Concrete examples of
commercial products would be, for example, MACROLEX Blue RR.RTM.,
MACROLEX Violet 3R.RTM., MACROLEX Violet B.RTM.(Lanxess AG,
Germany), Sumiplast Violet RR, Sumiplast Violet B, Sumiplast Blue
OR (Sumitomo Chemical Co., Ltd.), Diaresin Violet D, Diaresin Blue
G, Diaresin Blue N (Mitsubishi Chemical Corporation), Heliogen Blue
or Heliogen Green (BASF AG, Germany).
[0149] These colourants can be used in amounts of from 0.00001 wt.
% to 1.00000 wt. %, preferably from 0.00010 wt. % to 0.10000 wt. %
and particularly preferably from 0.00050 wt. % to 0.05000 wt.
%.
[0150] Particularly suitable demoulding agents for the composition
according to the invention are, for example, pentaerythritol
tetrastearate (PETS) or glycerol monostearate (GMS). Methods for
producing the polymer compositions according to the invention are
known to the person skilled in the art.
[0151] The preparation of the polymer compositions according to the
invention containing a thermoplastic plastic, an inorganic IR
absorber from the group of the borides, optionally one or more
colouring agents and optionally further conventional polymer
additives is carried out by conventional incorporation processes by
combining, mixing and homogenising the individual constituents, the
homogenisation in particular preferably being carried out in the
melt under the action of shear forces. Combining and mixing prior
to melt homogenisation are optionally carried out using powder
premixtures.
[0152] It is also possible to use premixtures which have been
prepared from solutions of the mixture components in suitable
solvents, homogenisation in solution optionally being carried out
and the solvent subsequently being removed.
[0153] In particular, the IR absorbers, colouring agents,
ultraviolet absorbers and other additives of the composition
according to the invention can be introduced by known processes or
in the form of a masterbatch.
[0154] The use of masterbatches is particularly preferred for the
introduction of the IR absorber, there being used in particular
masterbatches based on polycarbonate into which the IR absorbers
have been introduced in the form of a ready-to-use IR absorber
formulation containing dispersing agents, preferably polyacrylate-,
polyether- or polyester-based dispersing agents, preferably
dispersing agents having high temperature stability, such as a
polyacrylate (homo- or co-polymer), such as, for example,
polymethyl methacrylate, and/or polyesters or mixtures thereof,
further containing auxiliary substances such as, for example,
zirconium dioxide and optionally residual solvents such as, for
example, toluene, benzene or similar aromatic hydrocarbons. By
using such masterbatches in combination with the corresponding IR
absorber formulations, agglomeration of the IR absorber in the
polymer composition is effectively prevented.
[0155] In this connection, the composition can be combined, mixed,
homogenised and then extruded in conventional devices such as
screw-type extruders (for example twin-screw extruder, ZSK),
kneaders, Brabender or Banbury mills. After the extrusion, the
extrudate can be cooled and comminuted. It is also possible for
individual components to be premixed and the remaining starting
materials subsequently to be added separately and/or likewise as a
mixture.
[0156] In a particular embodiment, the IR absorber according to the
invention, before it is incorporated into the thermoplastic polymer
matrix, is optionally mixed with the nano-scale pigment according
to the invention and optionally further additives to form a
masterbatch, mixing preferably taking place in the melt under the
action of shear forces (for example in a kneader or twin-screw
extruder). This process offers the advantage that the IR absorber
can better be distributed in the polymer matrix. In order to
prepare the masterbatch, the thermoplastic plastic that also
constitutes the main component of the ultimate total polymer
composition is preferably chosen as the polymer matrix.
[0157] The masterbatch so prepared contains [0158] a. from 85.00
wt. % to 98.90 wt. %, preferably from 93.00 wt. % to 98.90 wt. %,
of a transparent thermoplastic plastic; [0159] b. from 0.10 wt. %
to 2.00 wt % boride as inorganic IR absorber, preferably lanthanum
hexaboride LaB.sub.6; and [0160] c. from 1.00 wt. % to 4.80 wt. %
dispersing agent; [0161] d. optionally from 0.00 wt. % to 0.20 wt.
%, preferably from 0.01 wt. % to 0.10 wt. %, of at least one
stabilizer selected from the group comprising phosphines,
phosphites and phenolic antioxidants and mixtures of these
stabilizers; [0162] e. optionally from 0.001 wt. % to 0.200 wt. %
inorganic nano-scale pigment, preferably carbon black; [0163] f.
optionally from 0.00 wt. % to 8.00 wt. % of at least one further
auxiliary substance and/or additive, such as, for example,
zirconium dioxide; [0164] g. optionally colouring agents, [0165]
wherein the sum of components a-g is 100 wt. %.
[0166] In a preferred embodiment, the inorganic IR absorber is
present in an acrylate matrix. In a further preferred embodiment,
the transparent thermoplastic plastic is a polycarbonate.
[0167] The polymer compositions according to the invention can be
processed to products or moulded bodies by, for example, first
extruding the polymer compositions as described to form a granulate
and processing the granulate by suitable processes into various
products or moulded bodies in known manner.
[0168] In this connection, the compositions according to the
invention can be converted, for example, by means of hot pressing,
spinning, blow moulding, deep drawing, extrusion or injection
moulding into products or moulded bodies, moulded objects such as
parts for toys, fibres, foils, tapes, sheets such as solid sheets,
multiwall sheets, twin-wall sheets or corrugated sheets,
containers, pipes or other profiles. The use of multilayer systems
is also of interest. Application can take place at the same time as
or immediately after moulding of the base body, for example by
coextrusion or multicomponent injection moulding. However,
application can also be to the finished moulded base body, for
example by lamination with a film or by coating with a
solution.
[0169] Sheets of a base layer and optional top layer/layers are
preferably produced by (co)extrusion, however.
[0170] For extrusion, the polymer composition, which has optionally
been pretreated, for example by means of drying, is fed to the
extruder and melted in the plastification system of the extruder.
The plastics melt is then pressed through a flat die or multiwall
sheet die and thereby shaped, is brought to the desired final form
in the roll gap of a smoothing calendar, and its shape is fixed by
alternate cooling on smoothing rollers and with ambient air. The
temperatures necessary for extrusion of the polymer composition are
set, it usually being possible to follow the manufacturer's
instructions. If the polymer compositions contain, for example,
polycarbonates having a high melt viscosity, they are normally
processed at melt temperatures of from 260.degree. C. to
350.degree. C., and the cylinder temperatures of the plastification
cylinder and the die temperatures are set accordingly.
[0171] By using one or more side extruders and a multiple manifold
die or optionally suitable melt adapters upstream of a flat die it
is possible to lay thermoplastic melts of different compositions
above one another and accordingly produce multilayer sheets or
foils (for coextrusion see, for example, EP-A 0 110 221, EP-A 0 110
238 and EP-A 0 716 919, for details of the adapter and die process
see Johannaber/Ast: "Kunststoff-Maschinenfuhrer", Hanser Verlag,
2000 and Gesellschaft Kunststofftechnik: "Coextrudierte Folien und
Platten: Zukunftsperspektiven, Anforderungen, Anlagen und
Herstellung, Qualitatssicherung", VDI-Verlag, 1990).
[0172] Preferred products or moulded bodies according to the
invention are sheets, foils, glazing, for example car windows,
windows of railway vehicles and aircraft, car sunroofs, roof
coverings or glazing for buildings, which contain the compositions
according to the invention. In addition to solid sheets, it is also
possible to use twin-wall sheets or multiwall sheets. In addition
to the compositions according to the invention, further material
components, for example, can be present in the products according
to the invention as further components of the products according to
the invention. For example, glazing can have sealing materials at
the edges of the panels. Roof coverings can have, for example,
metal components such as screws, metal pins or the like, which can
be used to secure or guide (in the case of folding or sliding
roofs) the roofing elements. Further materials can also be joined
to the compositions according to the invention, for example by
2-component injection moulding. For example, the corresponding
structural element having IR-absorbing properties can be provided
with an edge which is used, for example, for adhesive bonding.
[0173] In a particular embodiment, the articles produced from the
composition of the present invention are coated. This coating
serves to protect the thermoplastic material against general
weathering influences (e.g. damage by sunlight) as well as against
mechanical damage to the surface (e.g. scratching) and accordingly
increases the resistance of the correspondingly equipped
articles.
[0174] It is known that polycarbonate can be protected against UV
radiation by means of various coatings. Such coatings
conventionally contain UV absorbers. Such layers likewise increase
the scratch resistance of the corresponding article. The articles
of the present invention can carry single-layer or multilayer
systems. They can be coated on one side or on both sides. In a
preferred embodiment, the article contains a scratch-resistant
lacquer containing UV absorber. In a particular embodiment, the
multilayer product contains at least one layer containing the
composition according to the invention, at least one anti-UV layer
and optionally a scratch-resistant coating.
[0175] In the case of glazing materials, the article carries at
least one scratch-resistant or anti-reflection coating on at least
one side.
[0176] The preparation of the coating, for example an
anti-reflection coating, can be carried out by various methods. For
example, coating can be carried out by various methods of vapour
deposition, for example by electron beam processes, resistance
heating and by plasma deposition or various sputtering methods such
as high-frequency sputtering, magnetron sputtering, ion beam
sputtering, etc., ion plating by means of DC, RF, HCD methods,
reactive ion plating, etc. or chemical gas-phase deposition. An
anti-reflection coating can also be applied from solution.
[0177] Accordingly, a corresponding coating solution can be
prepared via a dispersion of a metal oxide having a high refractive
index, such as ZrO.sub.2, TiO.sub.2, Sb.sub.2O.sub.5 or WO.sub.3,
in a silicon-based lacquer, which coating solution is suitable for
the coating of plastics articles and can be cured thermally or with
UV assistance.
[0178] Various methods are known for producing a scratch-resistant
coating on plastics articles. For example, lacquers based on epoxy,
acrylic, polysiloxane, colloidal silica gel or inorganic/organic
materials (hybrid systems) can be used. Such systems can be
applied, for example, by dipping processes, spin coating, spraying
processes or flow coating. Curing can be carried out thermally or
by means of UV radiation. Single- or multi-layer systems can be
used. The scratch-resistant coating can be applied directly or
after preparation of the substrate surface with a primer.
Furthermore, a scratch-resistant coating can be applied by
plasma-assisted polymerisation processes, for example via an
SiO.sub.2 plasma. Anti-fog or anti-reflection coatings can likewise
be produced by plasma processes. It is further possible to apply a
scratch-resistant coating to the resulting moulded body by means of
specific injection-moulding processes, such as, for example, the
back-injection of surface-treated foils. Various additives, such
as, for example, UV absorbers derived, for example, from triazoles
or triazines, can be present in the scratch-resistant coating. IR
absorbers of organic or inorganic nature can also be present. Such
additives can be contained in the scratch-resistant lacquer itself
or in the primer layer. The thickness of the scratch-resistant
layer is from 1 to 20 .mu.m, preferably from 2 to 15 .mu.m. Below 1
.mu.m, the resistance of the scratch-resistant layer is
unsatisfactory. Above 20 .mu.m, cracks occur more frequently in the
lacquer. The base material according to the invention, which is
described in the present invention, is preferably provided with an
above-described scratch-resistant and/or anti-reflection layer
after the injection-moulded article has been produced, because the
preferred field of use is in the window or automotive glazing
sector.
[0179] For polycarbonates, a primer containing UV absorber is
preferably used in order to improve the adhesion of the
scratch-resistant lacquer. The primer can contain further
stabilizers such as, for example, HALS systems (stabilizers based
on sterically hindered amines), adhesion promoters, flow improvers.
The resin in question can be selected from a large number of
materials and is described, for example, in Ullmann's Encyclopedia
of Industrial Chemistry, 5th Edition. Vol. A18, pp. 368-426, VCH,
Weinheim 1991. Polyacrylates, polyurethanes, phenol-based,
melamine-based, epoxy and alkyd systems, or mixtures of these
systems, can be used. The resin is in most cases dissolved in
suitable solvents--frequently in alcohols. Depending on the chosen
resin, curing can take place at room temperature or at elevated
temperatures. Temperatures of from 50.degree. C. to 130.degree. C.
are preferably used--frequently after a large proportion of the
solvent has briefly been removed at room temperature. Commercially
obtainable systems are, for example, SHP470, SHP470FT2050 and
SHP401 from Momentive Performance Materials. Such coatings are
described, for example, in U.S. Pat. No. 6,350,512 B1, U.S. Pat.
No. 5,869,185, EP 1308084, WO 2006/108520.
[0180] Scratch-resistant lacquers (hard-coat) are preferably
composed of siloxanes and preferably contain UV absorbers. They are
preferably applied by dipping or flow processes. Curing takes place
at temperatures of from 50.degree. C. to 130.degree. C.
Commercially obtainable systems are, for example, AS4000, SHC5020
and AS4700 from Momentive Performance Materials. Such systems are
described, for example, in U.S. Pat. No. 5,041,313, DE 3121385,
U.S. Pat. No. 5,391,795, WO 2008/109072. The synthesis of these
materials is in most cases carried out by condensation of alkoxy-
and/or alkylalkoxy-silanes with acid or base catalysis.
Nanoparticles can optionally be incorporated. Preferred solvents
are alcohols such as butanol, isopropanol, methanol, ethanol and
mixtures thereof.
[0181] Instead of primer/scratch-resistant coating combinations,
one-component hybrid systems can be used. These are described, for
example, in EP0570165 or WO 2008/071363 or DE 2804283. Commercially
obtainable hybrid systems are obtainable, for example, under the
names PHC587 or UVHC 3000 from Momentive Performance Materials.
[0182] All the references described above are incorporated by
reference in their entireties for all useful purposes.
[0183] While there is shown and described certain specific
structures embodying the invention, it will be manifest to those
skilled in the art that various modifications and rearrangements of
the parts may be made without departing from the spirit and scope
of the underlying inventive concept and that the same is not
limited to the particular forms herein shown and described.
EXAMPLES
[0184] The invention is described in greater detail hereinbelow by
means of exemplary embodiments, the determination methods described
herein being used for all corresponding parameters in the present
invention unless indicated otherwise.
[0185] The melt volume rate (MVR) is determined in accordance with
ISO 1133 (at 300.degree. C.; 1.2 kg).
[0186] Measurement of the Scattering Effect:
[0187] Measurement of the colour takes place in reflection and is
carried out as follows:
[0188] The test specimen is illuminated at an angle of incidence of
60.degree. relative to the vertical using a white point light
source, and the scattering is measured at an emergent angle of from
30.degree. to -80.degree. relative to the vertical, and the CIELAB
colour coordinates L*, a*, b* are calculated in accordance with
ASTM E 308 using illuminant D65 and a 10.degree. observer (see FIG.
1). This colour system is described, for example, in Manfred
Richter: Einfuhrung in die Farbmetrik. 1984 ISBN 3-11-008209-8. For
the evaluation of the colour, the b* value with a 10.degree.
observer is used (referred to hereinbelow as b*(60.degree.)).
[0189] The measurements were carried out using a "Gon360-105"
goniophotometer (Gon360 with multichannel spectrometer CAS 140)
from Instrument Systems.
[0190] Hemispherical Reflection (b* Hemispherical)
[0191] The hemispherical reflection of the test specimen is
measured in accordance with ASTM E 1331 and the CIELAB colour
coordinates L*, a*, b* are calculated in accordance with ASTM E 308
using illuminant D65 and a 10.degree. observer. The corresponding
b*(hemispherical) value is given in the table.
[0192] .DELTA.b*: absolute value of the difference between
b*(60.degree.) and b*(hemispherical).
[0193] Determination of the T.sub.DS Value (Direct Solar
Transmittance):
[0194] The transmission and reflection measurements were carried
out using a Perkin Elmer Lambda 900 spectral photometer with a
photometer sphere (i.e. determination of total transmission by
measuring both the diffuse and direct transmission and the diffuse
and direct reflection). All the values were determined from 320 nm
to 2300 nm.
[0195] The total transmission T.sub.DS was calculated in accordance
with ISO 13837, computational convention "A".
[0196] Visual Light Transmission/Haze:
[0197] The transmission measurements were carried out using a
Perkin Elmer Lambda 900 spectral photometer with a photometer
sphere (i.e. determination of the total transmission by measuring
both the diffuse and direct transmission and the diffuse and direct
reflection) in accordance with ASTM D1003.
[0198] Materials:
[0199] For the production of the test specimens, additive-free
polycarbonate Makrolon 3108 from Bayer MaterialScience (linear
bisphenol A polycarbonate) having a melt volume index (MVR) of 6
cm.sup.3/10 min at 300.degree. C. and under a 1.2 kg load according
to ISO 1033 is used.
[0200] For the production of the test specimens, polycarbonate
Makrolon AL2647 from Bayer MaterialScience (linear polycarbonate
based on bisphenol A) having an MVR of 12.5 cm.sup.3/10 min at
300.degree. C. and under a 1.2 kg load according to ISO 1033 is
used. This polycarbonate contains UV absorber, demoulding agent and
heat stabilizer.
[0201] Lanthanum hexaboride LaB.sub.6 (KHDS 06 from Sumitomo Metal
Mining, Japan) is used as the IR absorber. The product is in the
form of a dispersion. The weights indicated in the examples relate
to lanthanum hexaboride as pure substance, the solids content of
lanthanum hexaboride in the commercial KHDS06 dispersion used being
21.5 wt. %.
[0202] Black Pearls.RTM. 800 from Cabot Corp. are used as the
nano-scale carbon black (particle size about 17 nm).
[0203] Makrolex Red EG from Lanxess Deutschland GmbH is employed as
the colouring agent of formula (1) or (2), where used.
[0204] Anthraquinone-based Macrolex Blue RR from Lanxess
Deutschland GmbH is used as a further colouring agent. A further
colouring agent used is Heliogen Blue K 6911D from BASF SE, 67065
Ludwigshafen, Germany.
[0205] Compounding:
[0206] Compounding of the additives was carried out in a type ZE25
twin-screw extruder from KrausMaffei Berstorff at a case
temperature of 260.degree. C., or a melt temperature of 270.degree.
C., and a speed of 100 rpm, with the amounts of additives indicated
in Table 1.
[0207] Test Specimens:
[0208] The granulate is dried for 3 hours in vacuo at 120.degree.
C. and then processed on an Arburg 370 injection-moulding machine
having a 25-injection unit at a melt temperature of 300.degree. C.
and a tool temperature of 90.degree. C. to form colour sample
sheets measuring 60 mm.times.40 mm.times.4 mm.
Example 1
Comparison Example
[0209] Makrolon.RTM. 3108 is compounded as described above without
further additives. The results of the reflection measurement are
given in Table 1.
Example 2
Comparison Example
[0210] Makrolon.RTM. 3108 is compounded as described above with
0.00086 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.004 wt. % KHDS 06 dispersion). The results of the reflection
measurement are given in Table 1.
Example 3
Comparison Example
[0211] Makrolon.RTM. 3108 is compounded as described above with
0.00108 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.005 wt. % KHDS 06 dispersion). The results of the reflection
measurement are given in Table 1.
Example 4
Comparison Example
[0212] Makrolon.RTM. 3108 is compounded as described above with
0.00215 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.01 wt. % KHDS 06 dispersion). The results of the reflection
measurement are given in Table 1.
Example 5
Comparison Example
[0213] Makrolon.RTM. 3108 is compounded as described above with
0.00430 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.02 wt. % KHDS 06 dispersion). The results of the reflection
measurement are given in Table 1.
Example 6
Comparison Example
[0214] Makrolon.RTM. 3108 is compounded as described above with
0.01075 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.05 wt. % KHDS 06 dispersion). The results of the reflection
measurement are given in Table 1.
Example 7
Comparison Example
[0215] Makrolon.RTM. 3108 is compounded as described above with
0.02150 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.1 wt. % KHDS 06 dispersion). The results of the reflection
measurement are given in Table 1.
Example 8
Comparison Example
[0216] Makrolon.RTM. 3108 is compounded as described above with
0.00430 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.02 wt. % KHDS 06 dispersion) and 0.0003 wt. % nano-scale carbon
black. The results of the reflection measurement are given in Table
1.
Example 9
Comparison Example
[0217] Makrolon.RTM. 3108 is compounded as described above with
0.00430 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.02 wt. % KHDS 06 dispersion) and 0.004 wt. % nano-scale carbon
black. The results of the reflection measurement are given in Table
1.
Example 10
According to the Invention
[0218] Makrolon.RTM. 3108 is compounded as described above with
0.00430 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.02 wt. % KHDS 06 dispersion) and 0.0025 wt. % nano-scale carbon
black. The results of the reflection measurement are given in Table
1.
Example 11
Comparison Example
[0219] Makrolon.RTM. AL2647 is compounded as described above with
0.00667 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.031 wt. % KHDS 06 dispersion) and 0.0005 wt. % nano-scale carbon
black and, as colouring agent, 0.0055 wt. % Macrolex Red EG, 0.0039
wt. % Macrolex Blue RR and 0.0013 wt. % Heliogen Blue K6911D. The
results of the reflection measurement are given in Table 2.
Example 12
According to the invention
[0220] Makrolon.RTM. AL2647 is compounded as described above with
0.00667 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.031 wt. % KHDS 06 dispersion) and 0.00167 wt. % nano-scale carbon
black and, as colouring agents, 0.0055 wt. % Macrolex Red EG,
0.0039 wt. % Macrolex Blue RR and 0.0013 wt. % Heliogen Blue
K6911D. The results of the reflection measurement are given in
Table 2.
Example 13
Comparison Example
[0221] Makrolon.RTM. AL2647 is compounded as described above with
0.00452 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.021 wt. % KHDS 06 dispersion) and 0.0005 wt. % nano-scale carbon
black and, as colouring agents, 0.0048 wt. % Macrolex Red EG,
0.0037 wt. % Macrolex Blue RR and 0.0011 wt. % Heliogen Blue
K6911D. The results of the reflection measurement are given in
Table 2.
Example 14
According to the Invention
[0222] Makrolon.RTM. AL2647 is compounded as described above with
0.00452 wt. % lanthanum hexaboride, LaB.sub.6 (which corresponds to
0.021 wt. % KHDS 06 dispersion) and 0.00225 wt. % nano-scale carbon
black and, as colouring agents, 0.0048 wt. % Macrolex Red EG,
0.0037 wt. % Macrolex Blue RR and 0.0011 wt. % Heliogen Blue
K6911D. The results of the reflection measurement are given in
Table 2.
TABLE-US-00001 TABLE 1 Change in the scattering effect by various
IR absorber/carbon black combinations Nano-scale Light carbon black
b* b* transmission Example No. LaB.sub.6 [wt. %] [wt. %]
(60.degree.) (hemi-spherical) .DELTA. b* T.sub.DS [%] [%] 1
(comparison) -- -- -0.6 -0.4 0.2 84.8 88.9 2 (comparison) 0.00086
-- -2.7 -0.4 2.3 76.4 84.4 3 (comparison) 0.00108 -- -3.2 0 3.2
67.4 82.5 4 (comparison) 0.00215 -- -4.8 0.4 5.2 54.0 75.5 5
(comparison) 0.00430 -- -6.7 0.3 7.0 36.5 62.6 6 (comparison)
0.01075 -- -7.5 -1.6 5.9 14.8 35.8 7 (comparison) 0.02150 -- -8.0
-3.4 4.6 5.0 14.8 8 (comparison) 0.00430 0.00030 -5.6 0.1 5.7 31.0
53.0 9 (comparison) 0.00430 0.00400 -1.4 -1.5 0.1 6.4 5.7 10
(according to 0.00430 0.00250 -2.2 -1.6 0.6 11.0 14.6 the
invention)
[0223] It is clear from Examples 2 to 7 that the scattering effect
caused by the IR absorber particles increases sharply with the
concentration of lanthanum hexaboride. Example 8 shows that small
amounts of carbon black are not suitable for markedly shifting the
b*(60.degree.) value towards 0 or into a range of from 0 to -2.5.
Furthermore, the .DELTA.b* value is markedly above 1 and is
accordingly clearly visible to the observer. Example 10 shows that
only relatively large amounts of carbon black exhibit the desired
effect. Furthermore, the difference between the bluish tinge caused
by the scattering effect and the reflected inherent colour is no
longer discernible (.DELTA.b* is less than 1). Too high
concentrations of carbon black, as shown in Example 9, drastically
reduce the transmission and are not suitable for transparent
moulded bodies. Surprisingly, it is also shown that the progression
of the b* value (b*(60.degree.)) responsible for the degree of
scattering is different from that of the reflected inherent colour
(b*(hemispherical)).
TABLE-US-00002 TABLE 2 Special colour settings Ex. 14 Ex. 12
according Ex. 11 according to Ex. 13 to the comparison the
invention comparison invention Macrolex Red 0.00550 0.00550 0.00480
0.00480 EG [wt. %] Macrolex Blue 0.00390 0.00390 0.00370 0.00370 RR
[wt. %] Heliogen Blue 0.00130 0.00130 0.00110 0.00110 K 6911D [wt.
%] Nano-scale 0.00050 0.00167 0.00050 0.00225 carbon black [wt. %]
LaB.sub.6 [wt. %] 0.00667 0.00667 0.00452 0.00452 Transmission Ty
20.1 8.1 25.5 7.8 b* in reflection -3.2 -1.7 -3.2 -1.3 b* in
reflection, -3.1 -2.3 -3.2 -2.0 hemispherical .DELTA.b* 0.1 0.6 0.0
0.7 T.sub.DS [%] 14.1 6.0 20.6 7.7
[0224] The scattering effect of the IR absorber particles is also
noticeable in the colour formulations. By means of the
concentrations according to the invention of nano-scale pigment, as
is shown in Examples 12 and 14, it is possible to reduce the
scattering effect (which can be recognised by the significant
increase in b*(60.degree.) in reflection, i.e. b* moves towards 0).
Even though .DELTA.b* for Examples 11 to 14 is in the range from 0
to 1 (i.e. the blue component of the inherent colour cannot be
distinguished from the component of the scattering effect), the
colour of the comparison examples with a b*(60.degree.) outside the
desired range is not acceptable for a neutral grey.
* * * * *