Note: Descriptions are shown in the official language in which they were submitted.
CA 02261716 1999-01-29
WO 98/05498 ~ ~ PCT/EP97/03854
Multilayered, transparently colored sheet of a crystallizable thermoplastic, a
process for its production and its use
The invention relates to an amorphous, transparently colored multilayered
sheet of a crystallizable thermoplastic, the thickness of which is in the
range from 1 to 20 mm. The invention furthermore relates to a process for
10 the production of this sheet and its use.
Multilayered sheets of plastics materials are known per se.
Such sheets of branched polycarbonates are described in EP-A-
0 247 480, EP-A-320 632 and US-PS 5,108,835.
UV-stabilized polycarbonate shaped articles which are built up from
polydiorganosiloxane-polycarbonate block copolymers are known from
DE-A-34 14 116 and US-A 4,600,632.
Multilayered sheets of plastic with layers of polydiorganosiloxane-
polycarbonate block copolymers which comprise UV absorbers are known
from US-A 5,137,949. UV-stabilized, branched polycarbonates from
specific diphenols are known from EP-A-0 416 404. It is mentioned that
25 such polycarbonates can be employed for the production of sheets or
webbed multiple sheets.
All these sheets are made of polycarbonate, an amorphous thermoplastic
which cannot be crystallized. Polycarbonate sheets have the disadvantage
30 that they often lead to blooming in the form of white specks and surface
deposits, especially in the UV-stabilized embodiment (cf. EP-A-0 649 724).
According to EP-A-0 649 724, for example, evaporating out of the UV
absorber is linked to a high degree to the average molecular weight.
35 These PC plates furthermore are readily flammable and therefore require
CA 02261716 1999-01-29
the addition of flameproofing agents so that they can be employed for
certain purposes, such as for interior applications. Tedious predrying times
and relatively long processing times at high temperatures are necessary for
further processing of these sheets to moldings. Devolatilizing extruders
5 must furthermore be used during sheet production for the purpose of
withdrawing moisture, which means that the additives added to the raw
material can also be removed at the same time, especially if low molecular
weight, relatively volatile additives are employed.
10 Single-layered, transparently colored amorphous sheets having a thickness
in the range from 1 to 20 mm which comprise a crystallizable
thermoplastic, such as, for example, polyethylene terephthalate, as the
main constituent, and at least one dyestuff which is soluble in this
thermoplastic have already been described by the Applicant (German
Patent Applications Nos.19519578.7,19522120.6 and 19528334.1 ~
WO 96/38498). These sheets can have a standard viscosity of 800-6000
and comprise a UV stabilizer. It goes without saying that the sheets,
starting substances, additives and processes described there can in
principle also be employed for the present invention, so that by citation,
20 these Applications belong to the disclosure content of the present
Application.
EP-A-0 471 528 describes a process for shaping an object from a
polyethylene terephthalate (PET) sheet. The PET sheet is heat-treated on
both sides in a thermoforming mold in a temperature range between the
25 glass transition temperature and the melting temperature. The shaped PET
sheet is removed from the mold when the extent of crystallization of the
shaped PET sheet is in the range from 25 to 50%. The PET sheets
disclosed in EP-A-0 471 528 have a thickness of 1 to 10 mm. Since the
thermoformed shaped article produced from this PET sheet is partly
30 crystalline and therefore no longer transparent and the surface properties
of the shaped article are determined by the thermoforming process and the
temperatures and shapes given by this, the optical properties (for example
AMENDED SHEET
.
CA 02261716 1999-01-29
2a
gloss, clouding and light transmission) of the PET sheets employed are
unimportant. As a rule,
AMENDED SHEET
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2b
lh'e addl~tion of ~l~r~ r~,ofin~ aqents so that they can ho~-~llployed for ~
certain purposes, such as for interior applications. Tedious predryingJ~mes
and relatively long processing times at high temperatures are nece~sary for
further processing of these sheets to moldings. Devolatilizing ex~Gders
5 must furthermore be used during sheet production for the pur~6se of
withdrawing moisture, which means that the additives addest~o the raw
material can also be removed at the same time, especialJ~if low molecular
weight, relatively volatile additives are employed.
10 Single-layered, transparently colored amorphous 7(eets having a thickness
in the range from 1 to 20 mm which comprise a~fystallizable
thermoplastic, such as, for example, polyethyl~he terephthalate, as the
main constituent, and at least one dyestuff ~ich is soluble in this
thermoplastic have already been describe,~by the Applicant (German
Patent Applications Nos.19519578.7,1,~522120.6 and 19528334.1).
These sheets can have a standard vis,~'osity of 800-6000 and comprise a
UV stabilizer. It goes without sayingJ~at the sheets, starting substances,
additives and processes described~here can in principle also be employed
for the present invention, so that~y citation, these Applications belong to
20 the disclosure content of the ps~sent Application.
EP-A-0 471 528 describes~2~ process for shaping an object from a
polyethylene terephthala~ (PET) sheet. The PET sheet is heat-treated on
both sides in a thermoffZlrrming mold in a temperature range between the
25 glass transition temp~!rature and the melting temperature. The shaped PET
sheet is removed f,~6m the mold when the extent of crystallization of the
shaped PET shett is in the range from 25 to 50%. The PET sheets
disclosed in EJ~A-0 471 528 have a thickness of 1 to 10 mm. Since the
thermoform~/d shaped article produced from this PET sheet is partly
30 crystallin~and therefore no longer transparent and the surface properties
of the ~aped article are determined by the thermoforming process and the
temp~ratures and shapes given by this, the optical properties (for example
gl~s, clouding and light transmission) of the PET sheets employed are
~'nirnport~nt. As Q rulo, phe optical properties of these sheets are poor and
CA 02261716 1999-01-29
in need of optimization. These polyethylene terephthalate sheets also have
a single-layer construction and are not colored.
US-A-3 496 143 describes vacuum thermoforming a 3 mm thick PET
5 sheet, the crystallization of which should be in the range from 5 to 25%.
The crystallinity of the thermoformed shaped article is greater than 25%.
On these PET sheets also, no requirements are imposed in respect of
optical properties. Since the crystallinity of the sheets employed is already
between 5% and 25%, these sheets are cloudy and nontransparent. These
10 partly crystalline PET sheets are also single-layered.
Austrian Patent Specification No. 304 086 describes a process for the
production of transparent shaped articles by the thermoforming process, a
PET sheet or film having a degree of crystallinity of less than 5% being
15 employed as the starting material.
The sheet or film used as the starting material has been produced from a
PET having a crystallization temperature of at least 1 60~C. From this
relatively high crystallization temperature it follows that the PET here is not
a PET homopolymer but a glycol-modified PET, called PET-G for short,
20 which is a PET copolymer.
In contrast to pure PET, PET-G shows an extremely low tendency toward
crystallization and is usually present in the amorphous state because of the
glycol units additionally incorporated.
25 The object of the present invention is to provide a multilayered,
amorphous, transparently colored sheet having a thickness of 1 to 20 mm
which is distinguished by good mechanical and optical properties.
Good optical properties include, for example, a high light transmission, a
30 high surface gloss, an extremely low clouding and a high image sharpness
(clarity).
Tl,o ~ m~~hG"j~;al properties in~u~, int~r ~ hig~ impact 3trcny.h
~n-l ~ high fr~cturc ~t~ ylh.
CA 02261716 1999-01-29
3 c~
30 The good mechanical properties include, inter alia, a high impact strength
and a high fracture strength.
AMENDED SHEET
CA 02261716 1999-01-29
- Furthermore, the sheet according to the invention should be recyclable, in
particular without loss of the mechanical properties, and poorly
combustible, so that, for example, it can also be used for interior
applications and in exhibition construction.
This object is achieved by a multilayered, transparently colored amorphous
sheet having a thickness of 1 to 20 mm, which comprises a crystallizable
thermoplastic as the main constituent, wherein the sheet has at least one
core layer and at least one covering layer, wherein the standard viscosity,
measured in dichloroacetic acid according to DIN 53728, of the
crystallizable thermoplastic of the core layer is higher than the standard
viscosity of the thermoplastic of the covering layer, and wherein at least
one layer of the sheet comprises at least one dyestuff which is soluble in
the thermoplastic of this layer.
15 Amorphous sheet in the context of the present invention is understood as
meaning those sheets which are noncrystalline, although the crystallizable
thermoplastic employed has a crystallinity of between 5 and 65%.
Noncrystalline, i.e. essentially amorphous, means that the degree of
crystallinity is in general below 5%, preferably below 2%, and particularly
20 preferably is 0%, and that the sheet essentially shows no orientation.
According to the invention, crystallizable thermoplastic is understood as
meaning
- crystallizable homopolymers,
- crystallizable copolymers,
25 - crystallizable compounds,
- crystallizable recycled material and
- other variations of crystallizable thermoplastics.
Examples of suitable thermoplastics are polyalkylene terephthalates with a
30 C1 to C12-alkylene radical, such as polyethylene terephthalate and
polybutylene terephthalate,
AMENDED SHEET
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4C~
~Fu~ ml~re, Ihe sheet according to tF~e invention s~ourd be~r~ecy'c~a~le~h
particular without loss of the mechanical properties, and poorly
combustible, so that, for example, it can also be used for interior~
applications and in exhibition construction.
This object is achieved by a multilayered, transparently cf~iored amorphous
sheet having a thickness of 1 to 20 mm, which compr7~s a crystallizable
thermoplastic as the main constituent, wherein the~eet has at least one
core layer and at least one covering layer, wherej~the standard viscosity
10 of the crystallizable thermoplastic of the core ~Çer is higher than the
standard viscosity of the thermoplastic of th~fcovering layer, and wherein
at least one layer of the sheet comprises~least one dyestuff which is
soluble in the thermoplastic of this laye~
15 Amorphous sheet in the context of ~Fe present invention is understood as
meaning those sheets which are,~Foncrystalline, although the crystallizable
thermoplastic employed has astFystallinity of between 5 and 65%.
Noncrystalline, i.e. essentiall~amorphous, means that the degree of
c~stallinity is in general be~bw 5%, preferably below 2%, and particularly
20 preferably is 0%, and tha~)~the sheet essentially shows no orientation.
According to the inv7~tion, crystallizable thermoplastic is understood as
meanlng ~,~
- crystalliza,p~e homopolymers,
25 - crystalli,7fable copolymers,
- cryst~Çzable compounds,
- cry~(allizable recycled material and
- ~er variations of crystallizable thermoplastics.
/
30 Ex~ples of suitable thermoplastics are polyalkylene terephthalates with a
C~( to C1 2-alkylene radical, such as polyethylene terephthalate and
/polyhutylenP tPrP~r~hthal~ts,¦polyalkylene naphthalate with a C1 to C12-
alkylene radical, and crystallizable cycloolefin polymers and cycloolefin
copolymers, it being possible for the thermoplastic or thermoplastics for the
CA 02261716 1999-01-29
core layer(s) and the thermoplastic or thermoplastics for the covering
layer(s) to be identical or different.
It has been found that a polyolefin is also suitable for the covering layer.
Thermoplastics having a crystallite melting point T", measured by DSC
(differential scanning calorimetry) with a heating-up rate of 10~C/minute, of
220~C to 260~C, preferably 230~C to 250~C, a crystallization temperature
range Tc of between 75~C and 260~C, a glass transition temperature Tg of
between 65~C and 90~C and a density, measured in accordance with DIN
53479, of 1.30 to 1.45 g/cm3 and a crystallinity of between 5% and 65%
are preferred polymers for the core layer and the covering layer as starting
materials for production of the sheet.
A thermoplastic having a cold (after-)crystallization temperature TCC of 120
to 158~C, in particular 130 to 158~C, is particularly preferred for the
purposes according to the invention.
The bulk density, measured in accordance with DIN 53466, is preferably
between 0.75 kg/dm3 and 1.0 kg/dm3, and particularly preferably between
0.80 kg/dm3 and 0.90 kg/dm3.
The polydispersity M,r/Mn of the thermoplastic, measured by means of
GPC, is preferably between 1.5 and 6.0, and particularly preferably
between 2.0 and 5Ø
A particularly preferred crystallizable thermoplastic for the core layer(s) and
the covering layer(s) is polyethylene terephthalate. The polyethylene
terephthalate preferably used according to the invention essentially
comprises monomer units of the following formula
O O
EC H2 - C H2 - O C ~ C O 3
CA 0226l7l6 l999-0l-29
It is essential to the invention that the thermoplastic or thermoplastics of
the core layer(s) has or have a higher standard viscosity than the
thermoplastic or thermoplastics of the covering layer(s). The standard
viscosities of the thermoplastics of various core and/or covering layers of a
5 multilayered sheet can differ.
The standard viscosity SV (DCA) of the crystallizable thermoplastic of the
core layer, measured in dichloroacetic acid in accordance with DIN 53728,
is preferably between 800 and 5000, and particularly preferably between
1000 and 4500.
The standard viscosity SV (DCA) of the crystallizable thermoplastic of the
covering layer, measured in dichloroacetic acid in accordance with DIN
53728, is preferably between 500 and 4500, and particularly preferably
between 700 and 4000.
The intrinsic viscosity IV (DCA) can be calculated from the standard
viscosity SV (DCA) as follows:
IV (DCA) = 6.67 x 10-4 SV (DCA) + 0.118
The crystallizable thermoplastics used according to the invention can be
obtained by customary processes known to the expert. In general,
thermoplastics such as are used according to the invention can be
obtained by polycondensation in the melt or by a two-stage
25 polycondensation. The first step here is carried out up to a moderate
molecular weight - corresponding to a moderate intrinsic viscosity IV of
about 0.5 to 0.7 - in the melt, and the further condensation is carried out by
means of solid condensation. The polycondensation is usually carried out
in the presence of known polycondensation catalysts or catalyst systems.
30 In the solid condensation, chips of the thermoplastic are heated at
temperatures in the range from 180 to 320~C under reduced pressure or
under an inert gas until the desired molecular weight is reached.
AMENDED SHEET
CA 02261716 1999-01-29
For example, the preparation of polyethylene terephthalate, which is
particularly preferred according to the invention, is described in detail in a
large number of patent applications, such as in JP-A-60-139 717, DE-C-2
429 087, DE-A-27 07 491, DE-A-23 19 089, DE-A-16 94 461, JP-63-41
528, JP-62-39 621, DE-A-41 17 825, DE-A-42 26 737, JP-60-141 715, DE-
A-27 21 501 and US-A-5 296 586.
Polyethylene terephthalates having particularly high molecular weights can
be prepared, for example, by polycondensation of dicarboxylic acid-diol
10 precondensates (oligomers) at elevated temperature in a liquid heat
transfer medium in the presence of customary polycondensation catalysts
and, if appropriate, cocondensable modifying agents, if the liquid heat
transfer medium is inert and free from aromatic structural groups and has a
boiling point in the range from 200 to 320~C, the weight ratio of the
15 dicarboxylic acid-diol precondensate (oligomer) employed to the liquid heat
transfer medium is in the range from 20:80 to 80:20, and the
polycondensation is carried out in a boiling reaction mixture in the
presence of a dispersion stabilizer.
20 It is essential to the invention that the amorphous, multilayered sheet
comprises at least one dyestuff which is soluble in the thermoplastic in at
least one of the layers. The concentration of the soluble dyestuff is
preferably in the range from 0.001 % by weight to 20% by weight, based on
the weight of the thermoplastic of the layer treated with this.
Soluble dyestuffs are understood as meaning substances which are
dissolved in the molecular state in the polymer (DIN 55949).
The change in color as a consequence of the coloration of the amorphous
30 sheet is based on the wavelength-dependent absorption and/or scattering
of the light. Dyestuffs can only absorb and not scatter light, since the
physical prerequisite for scattering is a certain minimum particle size.
Coloration with dyestuffs is a solution process. As a result of this solution
CA 02261716 1999-01-29
process, the dyestuff is dissolved in the molecular state, for example in the
PET polymer. Such colorations are described as transparent or
diaphanous or translucent or opal.
Of the various classes of soluble dyestuffs, the dyestuffs which are soluble
in fats and aromatic substances are particularly preferred. These are, for
example, azo and anthraquinone dyestuffs. They are particularly suitable
for coloring PET, since the migration of the dyestuff is limited due to the
high glass transition temperature of PET.
10 (Literature J. Koerner: Losliche Farbstoffe in der Kunststoffindustrie
[Soluble dyestuffs in the plastics industry] in VDI-Gesellschaft
Kunststofftechnik: Einfarben von Kunststoffen [Coloring of plastics], VDI-
Verlag, Dusseldorf 1975).
15 Suitable soluble dyestuffs are, for example: Solvent Yellow 93, a
pyrazolone derivative, Solvent Yellow 16, a fat-soluble azo dyestuff, Fluorol
Green Gold, a fluorescent polycyclic dyestuff, Solvent Red 1, an azo
dyesfuff, azo dyestuffs such as Thermoplastic Red BS, Sudan Red BB and
Solvent Red 138, an anthraquinone derivative, fluorescent benzopyran
20 dyestuffs, such as Fluorol Red GK and Fluorol Orange GK, Solvent Blue
35, an anthraquinone dyestuff, Solvent Blue, a phthalocyanine dyestuff,
and many others.
Mixtures of two or more of these soluble dyestuffs are also suitable.
The multilayered, transparently colored, amorphous sheet according to the
25 invention can furthermore be treated with further suitable additives, if
desired. These additives can be added individually or as a mixture to one
or more layers of the sheet, as required. These additives can also be
admixed to the layer(s) with the dyestuff. Examples of such additives are
UV stabilizers and antioxidants, such as are described in German Patent
30 Application No. 195 221 20.6 (WO 96/38498) and the Application by the
same Applicant, pending at the same time, entitled 'Polyethylene
terephthalate sheet of improved stability to hydrolysis'. By citation, these
AMENDED SHEET
.,
CA 02261716 1999-01-29
app ca~ ons are va d
i
/
AMENDED SHEET
CA 02261716 1999-01-29
9~
~iJ-tio." t"csc Q~ ;cahull~ dlt~ vdh~ ~S a constituent of the disclosure
content of the present Application.
As stated above, the multilayered, transparently colored, amorphous
5 sheets can additionally comprise at least one UV stabilizer as a light
stabilizer in the covering layer(s) and/or the core layer(s).
Light, in particular the ultraviolet portion of solar radiation, i.e. the
wavelength range from 280 to 400 nm, initiates degradation processes in
10 thermoplastics, as a consequence of which not only does the visual
appearance change, owing to a change in color or yellowing, but also the
mechanical-physical properties are adversely influenced.
Inhibition of these photooxidative degradation processes is of considerable
15 industrial and economic importance, since otherwise the possible uses of
numerous thermoplastics are limited drastically.
A high UV stability means that the sheet is not damaged or is damaged
only extremely little by sunlight or other UV radiation, so that the sheet is
20 suitable for exterior applications and/or critical interior applications, and shows little or no yellowing even after several years of external use.
Polyethylene terephthalates, for example, already start to absorb UV light
below 360 nm, and their absorption increases considerably below 320 nm
25 and is very pronounced below 300 nm. The maximum absorption is
between 280 and 300 nm.
In the presence of oxygen, chiefly chain splitting reactions but no
crosslinking reactions are observed here. Carbon monoxide, carbon
30 dioxide and carboxylic acids are the predominant photooxidation products
in terms of amount. In addition to direct photolysis of the ester groups,
oxidation reactions which likewise result in the formation of carbon dioxide
via peroxide radicals must also be taken into consideration.
The photooxidation of polyethylene terephthalates can also lead, via
CA 02261716 1999-01-29
elimination of hydrogen in the a-position of the ester groups, to
hydroperoxides and decomposition products thereof and to associated
chain scission reactions (H. Day, D. M. Wiles: J. Appl. Polym. Sci 16, 1972,
page 203).
UV stabilizers, also called light stabilizers or UV absorbers, are chemical
compounds which can intervene in the physical and chemical processes of
light-induced degradation.
10 Certain pigments, such as, for example, carbon black, can also partly have
the effect of light protection. However, these substances are unsuitable for
the transparently colored sheets according to the invention, since they lead
to discoloration or a change in color. Only those UV stabilizers, for
example, from the class of organic and organometallic compounds which
15 cause very little or no color or change in color in the thermoplastic to be
stabilized are expediently used for amorphous sheets.
Examples of UV stabilizers which are suitable for the present invention are
2-hydroxybenzophenones, 2-hydroxybenzotriazoles, organonickel
20 compounds, salicylic acid esters, cinnamic acid ester derivatives,
resorcinol monobenzoates, oxalic acid anilides, hydroxybenzoic acid
esters, sterically hindered amines and triazines, 2-hydroxybenzotriazoles
and triazines being preferred.
Mixtures of several UV stabilizers can also be employed.
The UV stabilizer is expediently present in a layer in a concentration of
0.01% by weight to 8% by weight based on the weight of the thermoplastic
in the layer treated with the stabilizer.
30 However, if the UV stabilizer is added to a core layer, a concentration of
0.01% by weight to 1% by weight, based on the weight of the thermoplastic
in the core layer treated with the stabilizer, is in general sufficient.
According to the invention, several layers can be treated simultaneously
with UV stabilizer. In general, however, it is sufficient for the layer on which
CA 02261716 1999-01-29
1 1
the UV radiation impinges to be treated.
The core layer(s) can be treated in order to prevent UV radiation impairing
the underlying core layer in the event of possible damage to the covering
5 layer.
In a particularly preferred embodiment, the transparently colored,
amorphous sheet according to the invention comprises, as the main
constituent, a crystallizable polyethylene terephthalate for the core layer
and covering layer and 0.01% by weight to 8.0% by weight of 2-(4,6-
diphenyl-1,3,5-triazin-2-yl)-5-(hexyl)oxyphenol or 0.01% by weight to 8.0%
by weight of 2,2'-methylenebis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-
tetramethylbutyl)phenol in the covering layer.
15 The sheet according to the invention can also be treated with at least one
antioxidant.
Antioxidants are chemical compounds which can delay the oxidation and
hydrolysis phenomena and the resulting aging.
20 Antioxidants which are suitable for the sheet according to the invention can
be classified as follows:
Additive group Substance class
primary antioxidants sterically hindered phenols and/or
secondary aromatic amines
secondary antioxidants phosphites and phosphonites, thioethers,
carbodiimides, zinc dibutyl-dithiocarbamate
In a preferred embodiment, the amorphous sheet according to the
invention comprises a phosphite and/or a phosphonite and/or a
carbodiimide as a hydrolysis and oxidation stabilizer.
Examples of antioxidants used according to the invention are 2-[(2,4,8,10-
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12
tetrakis(1 ,1 -dimethylethyl)dibenzo[d,f][1 ,3,2]dioxaphosphepin-6-yl]oxy)-
ethyl]ethanamine and tris(2,4-di-tert-butylphenyl) phosphite.
The antioxidant is usually present in a concentration of 0.01 to 6% by5 weight, based on the weight of the thermoplastic of the layer treated with
this.
Mixtures of primary and secondary antioxidants and/or mixtures of
secondary and/or primary antioxidants with UV stabilizers can furthermore
10 be used. It has been found, surprisingly, that such mixtures show a
synergistic effect.
The thickness of the multilayered sheet according to the invention varies
between 1 mm and 20 mm, it being possible for the thickness of the
15 covering layer(s) to be between 10 ,um and 1 mm, depending on the sheet
thickness. The covering layers preferably each have a thickness of
between 400 and 500 ,um.
As already stated, the sheet according to the invention can have several
20 core and covering layers which are laid one on top of the other like a
sandwich. However, the sheet can also consist of only one covering layer
and one core layer.
A structure having two covering layers and a core layer Iying between the
25 covering layers is particularly preferred according to the invention.
The individual covering and core layers can comprise different or identical
crystallizable thermoplastics as the main constituents, as long as the
thermoplastic of a core layer has a higher standard viscosity than the
30 thermoplastic of the covering layers directly adjacent to this core layer.
If desired, the transparently colored, amorphous, multilayered sheet
according to the invention can be provided with a scratch-resistant surface
on one or more sides.
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Possible coating systems and materials for the scratch-resistant surface
(coating) are all the systems and materials known to the expert.
Suitable coating systems and materials are described, in particular, in
German Patent Application No.196 255 34.1 of the Applicant, to the full
5 content of which reference is made for the present invention.
From the large number of possible coating systems and materials, some
are mentioned as examples below.
(1) US-A-4822828 discloses aqueous, radiation-curable coating
compositions which comprise, in each case based on the weight of the
dispersion, (A) from 50 to 85% of a silane having vinyl groups, (B) from 15
to 50% of a multifunctional acrylate and, if appropriate, (C) 1 to 3% of a
photoinitiator.
(2) Inorganic/organic polymers, so-called ormocers (organically
modified ceramics), which comblne the properties of ceramic materials and
polymers, are also known. Ormocers are employed, in particular, as hard
and/or scratch-resistant coatings on polymethyl methacrylate (PMMA) and
20 polycarbonate (PC). The hard coatings are bonded on the basis of Al2O3,
ZrO2, TiO2 or SiO2 as network formers and epoxide or methacrylate groups
with Si by -Si-C-- compounds.
(3) Coating compositions for acrylic resin plastics and polycarbonate
25 based on silicone resins in aqueous-organic solution which have a
particularly high storage stability are described, for example, in EP-A-0 073
362 and EP-A-0 073 911. This technique uses the condensation products
of partially hydrolyzed organosilicon compounds as coating compositions,
above all for glass, and in particular for acrylic resin plastics and PC.
(4) Acrylic-containing coatings are also known, such as, for example,
the Uvecryl coatings from UCB Chemicals. One example is Uvecryl 29203,
which is cured with UV light. This material comprises a mixture of urethane
acrylate oligomers with monomers and additives. Constituents are about
CA 02261716 1999-01-29
14
81% of acrylate oligomer and 19% of hexanediol diacrylate. These
coatings are likewise described for PC and PMMA.
(5) CVD or PVD coating technologies with the aid of a polymerizing
5 plasma and diamond-like coatings are also described in the literature
(Dunnschichttechnologie [Thin-layer technology], edited by Dr.Hartmut
Frey and Dr. Gerhard Kienel, VDI Verlag, Dusseldorf, 1987). These
technologies are used here in particular for metals, PC and PMMA.
10 Other commercially obtainable coatings are, for example, Peeraguard from
Peerless, Clearlite and Filtalite from Charvo, coating types such as, for
example, the UVHC series from GE Silicones, Vuegard such as the 900
series from TEC Electrical Components, Highlink OG series from Société
Francaise Hoechst, PPZ~ products marketed by Siber Hegner (produced
15 by Idemitsu) and coating materials from Vianova Resins, Toagoshi,
Toshiba or Mitsubishi. These coatings are also described for PC and
PMMA.
Coating processes known from the literature are, for example, offset
20 printing, casting, dipping processes, flow coating processes, spray
processes or atomizing processes, knife-coating or rolling.
Coatings applied by the processes supplied are then cured, for example by
means of UV radiation and/or heat. For the coating processes, it may be
25 advantageous to treat the surface to be coated with a primer, for example
based on acrylate or an acrylic latex, before application of the coating.
Other known processes are, for example:
CVD processes and vacuum plasma processes, such as, for example,
30 vacuum plasma polymerization, PVD processes, such as coating with
electron beam vaporization, resistance-heated vaporizer sources or
coating by conventional processes under a high vacuum, such as in the
case of a conventional metallization.
CA 02261716 1999-01-29
Literature on CVD and PVD is, for example: Moderne
Beschichtungsverfahren [Modern coating processes] by H.-D. Steffens and
W. Brandl. DGM Informationsgesellschaft Verlag Oberursel. Other
literature on coatings: Thin Film Technology by L. Maissel, R. Glang,
5 McG raw-Hill, New York ( 1 983) .
Coating systems which are particularly suitable for the purposes of the
present invention are systems (1), (2), (4) and (5), coating system (4) being
particularly preferred.
Suitable coating processes are, for example, also the casting, the spraying,
the atomizing, the dipping and the offset process, the atomizing process
being preferred for coating system (4).
15 For coating the amorphous, crystallizable sheets, curing with UV radiation
and/or at temperatures which preferably do not exceed 80~C can be
carried out, UV curing being preferred.
The coating according to system (4) has the advantage that no
20 crystallization which could cause clouding occurs. Furthermore, the coating
shows an outstanding adhesion, outstanding optical properties and a very
good resistance to chemicals and causes no impairment of the intrinsic
color.
25 The thickness of the scratch-resistant coating is in general between 1 and
50 lum.
The amorphous sheet according to the invention, which comprises a
crystallizable thermoplastic, such as, for example, PET, as the main
30 constituent, has outstanding mechanical and optical properties. Thus,
when the impact strength an according to Charpy (measured in accordance
with ISO 179/1 D) is measured on the sheet, preferably no fracture occurs.
Furthermore, the notched impact strength ak according to Izod (measured
in accordance with ISO 180/1 A) of the sheet is preferably in the range from
CA 02261716 1999-01-29
16
2.0 to 8.0 kJ/m2, particularly preferably in the range from 4.0 to 6.0 kJ/m2.
The image sharpness of the sheet, which is also called clarity and is
determined under an angle of less than 2.5~ (ASTM D 1003), is preferably
5 more than 83%, and particularly preferably more than 84%.
The surface gloss, measured in accordance with DIN 67530 (measurement
angle 20~), is greater than 100, preferably greater than 110, the light
transmission, measured in accordance with ASTM D 1003, is in general
between 5 and 90%, preferably between 10 and 80%, and the clouding of
the sheet, measured in accordance with ASTM D 1003, is in the range
from 2 to 50, preferably 10 - 35%.
Weathering tests have shown that, even after 5 to 7 years of exterior use,
15 the UV-stabilized sheet according to the invention shows no visible
yellowing and no visible loss of gloss, as well as no visible surface defects.
Furthermore, the sheet according to the invention is poorly flammable and
produces non-burning drips with very little evolution of smoke, so that it is
20 also particularly suitable for interior applications and in exhibition
construction.
The sheet according to the invention furthermore can recycled without
problems, without pollution of the environment and without loss in the
25 mechanical properties, which means that it is suitable, for example, for the
production of short-lived advertising signs or other advertising articles.
Outstanding and economical thermoforming properties (heat forming and
vacuum forming properties) have in addition completely unexpectedly been
30 found. Surprisingly, in contrast to polycarbonate sheets, it is not necessaryto predry the sheet according to the invention before thermoforming. For
example, polycarbonate sheets must be predried at about 125~C for 3 to
50 hours before thermoforming, depending on the sheet thickness.
CA 02261716 1999-01-29
Furthermore, the sheet according to the invention can be obtained with
very low thermoforming cycle times and at low temperatures during the
thermoforming. On the basis of these properties, shaped articles can be
produced economically and with a high productivity from the sheet
5 according to the invention on customary thermoforming machines.
The production of the multilayered, transparently colored, amorphous
sheets according to the invention can be carried out, for example, by the
coextrusion process known per se in an extrusion line.
Coextrusion as such is known from the literature (cf., for example,
EP-110 221 and EP-110 238).
In this case, an extruder for plasticizing and producing the core layer and a
15 further extruder per covering layer are each connected to a coextruder
adapter. The adapter is constructed such that the melts which form the
covering layers are applied as thin layers adhesively to the melt of the core
layer. The multilayered melt strand thus produced is then shaped in the
downstream die and sized, polished and cooled in the polishing stack,
20 before the sheet is cut to size.
The process for the production of the sheets according to the invention is
described generally below.
25 If necessary, the thermoplastic polymer can be dried before the
coextrusion.
Drying can expediently be carried out at temperatures in the range from
110 to 1 90~C over a period of 1 to 7 hours. The main drier is connected to
the main extruder, and, per covering layer, one drier is connected to a
30 coextruder.
Thereafter, the thermoplastic or the thermoplastics for the core layer(s) and
the covering layer(s) are melted in the main extruder and in the
coextruders. The temperature of the melt is preferably in the range from
CA 02261716 1999-01-29
230 to 330~C, it then being possible for the temperature of the melt to be
established essentially both by the temperature of the extruder and by the
residence time of the melt in the extruder.
If polyethylene terephthalate, which is preferred according to the invention
as the thermoplastic, is used, drying is usually carried out at 160 to 1 80~C
for 4 to 6 hours and the temperature of the melt is established in the range
from 250 to 320~C.
10 The dyestuff and, if appropriate, the additives, such as a UV stabilizer
and/or an antioxidant, can already be metered in by the manufacturer of
the raw material, or can be metered into the extruder during sheet
production. Addition of the dyestuff and, if appropriate, the additives via
masterbatch technology is particularly preferred. In this case, the dyestuff
and, if appropriate, the additives are dispersed completely in a solid carrier
material. Possible carrier materials are certain resins, the thermoplastic
itself or also other polymers which are sufficiently compatible with the
tnermoplastic.
20 It is important that the particle size and bulk density of the masterbatch are
similar to the particle size and bulk density of the thermoplastic, so that
homogeneous distribution and thus a homogeneous effect of the dyestuff
and additives, such as, for example, homogeneous coloration and
stabilization to UV and hydrolysis, can be achieved.
As already stated, the main extruder for production of the core layer and
the coextruder or coextruders are connected to a coextruder adapter such
that the melts forming the covering layers are applied as thin layers
adhesively to the melt of the core layer. The multilayered melt strand thus
produced is shaped in a die connected to the line. This die is preferably a
slot die.
The multilayered melt strand shaped by a slot die is then sized by polishing
calender rolls, i.e. cooled intensively and polished. The calender rolls used
CA 02261716 1999-01-29
can be arranged, for example, in an 1-, F-, L- or S-shape.
The material can then be after-cooled on a roller conveyor, trimmed to size
at the edges, cut to length and stacked.
The thickness of the resulting sheet is essentially determined by the take-
off, which is positioned at the end of the cooling zone, by the cooling
(polishing) rolls coupled to this in terms of speed, and by the conveying
speed of the extruder on the one hand and the distance between the rolls
on the other hand.
Both single-screw and twin-screw extruders can be employed as the
extruder.
The slot die preferably comprises the dismountable die body, the lips and
the restrictor bar for flow regulation via the width. For this, the restrictor bar
can be bent by tension and pressure screws. The thickness is set by
adjusting the lips. It is important to ensure that the multilayered melt strand
and the lip have a uniform temperature, since otherwise the melt strand
flows out in different thicknesses as a result of the different flow paths.
The sizing die, i.e. the polishing calender, gives the melt strand its shape
and dimensions. This is effected by freezing to below the glass transition
temperature by means of cooling and polishing. Shaping should no longer
take place in this state, since otherwise surface defects would form
because of the cooling which has taken place. For this reason, the
calender rolls are preferably driven jointly. The temperature of the calender
rolls must be lower than the crystallite melting temperature in order to avoid
sticking of the melt strand. The melt strand preferably leaves the slot die
with a temperature of 240 to 300~C. The first polishing/cooling roll has a
temperature between 50~C and 80~C, depending on the output and sheet
thickness. The second, somewhat cooler roll cools the second or other
surface.
CA 02261716 1999-01-29
To obtain a uniform thickness in the range from 1 to 20 mm, with good
optical properties, it is essential for the temperature of the first polishing roll
to be 50 to 80~C.
5 While the sizing device freezes the surfaces of the sheet as smoothly as
possible and cools the profile to the extent that it is dimensionally stable,
the after-cooling device lowers the temperature of the sheet to virtually
room temperature. After-cooling can take place on a roller board.
10 The speed of the take-off should be coordinated precisely with the speed
of the calender rolls in order to avoid defects and variations in thickness.
As additional devices, the extrusion line for production of the sheets
according to the invention can comprise a separating saw as a device for
15 cutting to length, the edge trimmer, the stacking unit and a control station. The edge or margin trimmer is advantageous, since under certain
circumstances the thickness in the margin region may be nonuniform. The
thickness and visual properties of the sheet are measured at the control
station.
As a result of the surprisingly large number of excellent properties, the
transparently colored, amorphous sheet according to the invention is
outstandingly suitable for a large number of various uses, for example for
interior paneling, for exhibition construction and exhibition articles, as
25 displays, for signs, in the illumination sector, in shopfitting and shelf
construction, as advertising articles, as menu stands, as basketball
backboards, as room dividers, as aquaria, as information boards, as
brochure and magazine stands, and also for extemal applications, such as,
for example, greenhouses, roofing, exterior paneling, coverings, for
30 applications in the building sector, illuminated advertising profiles, balcony
paneling and skylights.
The invention is illustrated in more detail in the following with the aid of
embodiment examples, without being limited by these.
CA 02261716 1999-01-29
Measurement of the individual properties is carried out here in accordance
with the following standards or methods.
Measurement methods
Surface gloss:
The surface gloss is determined at a measurement angle of 20~ in
accordance with DIN 67 530. The reflector value is measured as the
optical parameter for the surface of a sheet. In accordance with the
standards ASTM-D 523-78 and ISO 2813 the angle of incidence was set at
20~. Under the angle of incidence set, a ray of light strikes the flat test
surface and is reflected or scattered by it. The rays of light incident on the
photoelectronic receiver are indicated as a proportional electrical value.
The measurement value is dimensionless and must be stated together with
15 the angle of incidence.
Light transmission:
Light transmission is to be understood as meaning the ratio of the total light
allowed through to the amount of incident light.
The light transmission is measured with the ~Hazegard plus" measuring
instrument in accordance with ASTM D 1003.
Clouding and Clarity:
25 Clouding is the percentage content of the light allowed through which
deviates from the incident light bundle on average by more than 2.5~. The
image sharpness is determined under an angle of less than 2.5~.
The clouding and the clarity are measured with the "Hazegard plus"
30 measuring instrument in accordance with ASTM D 1003.
Surface defects:
The surface defects are determined visually.
CA 0226l7l6 l999-0l-29
-
22
Charpy impact strength an:
This value is detemmined in accordance with ISO 179/1.
Izod notched impact strength ak:
5 The Izod notched impact strength or resistance ak is measured in
accordance with ISO 180/1A.
Density:
The density is determined in accordance with DIN 53479.
SV (DCA), IV (DCA):
The standard viscosity SV (DCA) is measured in dichloroacetic acid in
accordance with DIN 53728.
15 The intrinsic viscosity (IV) is calculated as follows from the standard
viscosity (SV)
IV (DCA) = 6.67 x 104 SV (DCA) + 0.118
20 Thermal properties:
The thermal properties, such as crystallite melting point Tm~ crystallization
temperature range Tc, after-(cold)crystallization temperature TCC and glass
transition temperature Tg are measured by means of differential scanning
calorimetry (DSC) at a heating-up rate of 1 0~C/minute.
Molecular weight, polydispersity:
The molecular weights Mw and Mn and the resulting polydispersity MW/Mn
are measured by means of gel pemmeation chromatography (GPC).
~,~1:
A 4 m~ayered, transparently colored, amorphous polyethylene
terephthalate sheetl;3~er sequence A-B-A is produced by the
coextrusion process described, B rep~ r.tinq the base layer and A the
c~rin~ l~y~r Thr- hA~ y~ C ic 3.~ ~nm thi~k ~ ~ ~ rovoring
CA 02261716 1999-01-29
22 C~
Example 1:
A 4 mm thick, multilayered, transparently colored, amorphous polyethylene
30 terephthalate sheet having the layer sequence A-B-A is produced by the
coextrusion process described, B representing the base layer and A the
covering layer. The base layer B is 3.5 mm thick and the two covering
AMENDED SHEET
CA 02261716 1999-01-29
layers, which coat the base layer, are each 250 ,um thick.
The polyethylene terephthalate employed for the base layer B has the
following properties:
SV (DCA) : 1100
IV (DCA) : 0.85 dl/g
Density : 1.38 g/cm3
Crystallinity : 44 %
Crystallite melting point Tm : 245~C
Crystallization temperature range Tc : 82 to 245~C
After-(cold)crystallization temperature range TCC : 152~C
Polydispersity M~JMn : 2.02
Glass transition temperature : 82~C
The base layer comprises the polyethylene terephthalate described, as the
main constituent, and 2% by weight of the soluble dyestuff Solvent Red
138, an anthraquinone derivative from BASF ((É)Thermoplast G).
The soluble dyestuff Solvent Red 138 is added in the form of a
masterbatch. The masterbatch is composed of 20% by weight of the
dyestuff Solvent Red 138, as the active compound component, and 80%
by weight of the polyethylene terephthalate polymer described above, as
the carrier material.
The polyethylene terephthalate from which the covering layers are
produced has a standard viscosity SV (DCA) of 1007.5, which corresponds
to an intrinsic viscosity IV (DCA) of 0.79 dl/g. The moisture content is
< 0.2% and the density (DIN 53479) is 1.41 g/cm3. The crystallinity is 59%,
the
AMENDED SHEET
CA 02261716 1999-01-29
- 23O_
- ~'ayers; whlch ~at the base~layer, a~r~ e~r~h 250 ~m thi6k. ~?
The polyethylene terephthalate employed for the base layer ~ as the
following properties:
SV (DCA) / 1100
IV (DCA) / : 0.85 dl/g
Density ~ : 1.38 g/cm3
Crystallinity ~ : 44 %
Crystallite melting point Tm ~ 245~C
Crystallization temperature range Tc ~ : 82 to 245~C
After-(cold)crystallization temperatu~range TCC : 152~C
Polydispersity M~Mn ~ : 2.02
Glass transition temperature ~ : 82~C
The base layer comprises~e polyethylene terephthalate described, as the
main constituent, and 2~ by weight of the soluble dyestuff Solvent Red
138, an anthraquino~derivative from BASF ((~)Thermoplast G).
/
20 The soluble dye~uff Solvent Red 138 is added in the form of a
masterbatch. ;~e masterbatch is composed of 20% by weight of the
dyestuff So~yent Red 138, as the active compound component, and 80%
by weightf5f the polyethylene terephthalate polymer described above, as
the car?~r material.
The/polyethylene terephthalate from which the covering layers are
p~duced has a standard viscosity SV (DCA) which corresponds to an
jhtrinsic viscosity IV (DCA) of 0.79 dl/g. The moisture content is < 0.2% and
JthF! ~lPnc~ ~4/~ l~ l.q1 ~cm3. Tl~ y~ nlly ;~ ~tO~the
30 crystallite melting point, according to DSC measurements, being 258~C.
The crystallization temperature range Tc is between 83~C and 258~C, the
after-crystallization temperature (also the cold crystallization temperature)
TCC being 144~C. The polydispersity M~JMn of the polyethylene
terephthalate polymer is 2.14.
CA 02261716 1999-01-29
24
- The glass transition temperature is 83~C.
Before the coextrusion, 90% by weight of the polyethylene terephthalate
for the base layer and 10% by weight of the masterbatch are mixed and
5 the mixture is dried at 170~C for 5 hours in the main dryer, which is
connected to the main extruder.
The polyethylene terephthalate for the covering layer is likewise dried at
1 70~C for 5 hours in two smaller dryers which are connected to the two
1 0 coextruders.
The polyethylene terephthalate for the base or core layer and the
masterbatch are melted in the main extruder and the polyethylene
terephthalate for the covering layers are melted in the coextruders. The
15 extrusion temperature of the main extruder for the core layer is 281 ~C.
The extrusion temperatures of the two coextruders for the covering layers
are 294~C. The main extruder and the two coextruders are connected to a
coextruder adapter, which is constructed such that the melts which form
20 the covering layers are applied as thin layers adhesively to the melt of the
core layer. The multilayered melt strand thus produced is shaped in the
slot die, connected to the line, and polished on a polishing calender, the
rolls of which are arranged in an S-shape, to a three-layered sheet 4 mm
thick.
The first calender roll has a temperature of 65~C and the subsequent rolls
each have a temperature of 58~C. The speed of the take-off is
4.2 m/minute.
30 After the after-cooling, the three-layered transparent sheet is trimmed at
the edges with separating saws, cut to length and stacked.
The transparently colored, amorphous, three-layered PET sheet produced
has the following properties
CA 02261716 1999-01-29
- Layer construction : A-B-A
- Totalthickness : 4 mm
- Thickness ofthe base layer : 3.5 mm
- Thickness of the covering layers : 0.25 mm each
- Color : red-transparent
- Surface gloss 1st side : 160
(measurement angle 20~) 2nd side : 153
- Light transmission : 36.9%
- Clarity : 99.0%
- Clouding : 3.8%
- Surface defects per m2 : none
(specks, orange peel, bubbles and the like)
- Charpy impact strength an : no fracture
- Izod notched impact strength ak : 4.9 kJ/m2
- Cold forming properties : good, no defects
- Crystallinity : o%
- Density : 1.33 g/cm3
- Calender roll deposits
after 2 hours of production : none
Example 2:
A three-layered, red-transparently colored, amorphous sheet is produced
analogously to Example 1.
25 The polyethylene terephthalate employed for the base or core layer B has
the following properties:
- SV (DCA) 3173
- IV (DCA) : 2.23 dl/g
- Density : 1.34 g/cm3
- Crystallinity : 12%
- Crystallite melting pointTm : 240~C
- Crystallization temperature range Tc : 82~C to 240~C
- Cold crystallization temperature TCC : 156~C
CA 02261716 1999-01-29
26
- Polydispersity M~JMn : 3.66
- Glass transition temperature : 82~C
Mw : 204,660 g/mol
- Mn : 55,952 g/mol
As in Example 1, the soluble dyestuff Solvent Red 138 is added via
masterbatch technology. The base layer comprises only 1.0% by weight of
the dyestuff Solvent Red 138, i.e. only 5% by weight of the masterbatch is
metered into the polyethylene terephthalate of the base layer.
The extrusion temperature is 274~C. The first calender roll has a
temperature of 50~C and the subsequent rolls have a temperature of 45~C.
The speed of the take-off and of the calender rolls is 2.4 m/minute.
15 The sheet produced has the following properties:
- Layer construction : A-B-A
- Thickness of the covering layers : 0.4 mm each
- Thickness of the base layers : 5.2 mm
- Total thickness : 6 mm
- Color : red-transparent
- Surface gloss 1 st side : 162
(measurement angle 20~) 2nd side : 159
- Light transmission : 68.4%
- Clarity : 99.1 %
- Clouding : 3.2%
- Surface defects per m2 : none
(specks, orange peel, bubbles and the like)
- Charpy impact strength an : no fracture
- Izod notched impact strength ak : 5.1 kJ/m2
- Cold forming properties : good, no defects
- Crystallinity : o%
- Density : 1.33g/cm3
- Calender roll deposits
CA 02261716 1999-01-29
- 27
after 2 hours : none
Example 3
A transparently colored, three-layered, amorphous sheet is produced
5 analogously to Example 1. The base layer of the sheet comprises 4% by
weight of the soluble dyestuff Solvent Blue 35, a fat-soluble anthraquinone
dyestuff from BASF (t~Sudanblau 2).
The 4% by weight of the dyestuff Solvent Blue 35 is likewise added in the
form of a masterbatch, the masterbatch being composed of 20% by weight
10 of the dyestuff Solvent Blue 35 and 80% of the polyethylene terephthalate
polymer of the base layer from Example 1. 80% by weight of the
polyethylene terephthalate polymer of the base layer from Example 1 is
employed with 20% by weight of the masterbatch.
15 The blue-transparently colored sheet produced has the following properties
profile:
- Layer construction : A-B-A
- Total thickness : 4 mm
- Thickness of the base layer : 3.5 mm
- Thickness of the covering layers : 0.25 mm each
- Color : blue-transparent
- Surface gloss 1st side : 163
(measurement angle 20~) 2nd side : 158
- Light transmission : 30.6%
- Clarity 99.0%
- Clouding 4.7%
- Surface defects per m2 : none
(specks, orange peel, bubbles and the like)
- Charpy impact strength an : no fracture- Izod notched impact strength ak : 4.9 kJ/m2
- Coldforming properties : good, no defects
- Crystallinity o%
- Density : 1.33 g/cm3
CA 02261716 1999-01-29
- Calender roll deposits
after 2 hours : none
Comparison Example 1:
5 A transparently colored sheet is produced analogously to Example 1. The
covering layers are analogous to the covering layers from Example 1. The
polyethylene terephthalate employed in the base layer has a standard
viscosity SV (DCA) of 760, which corresponds to an intrinsic viscosity IV
(DCA) of 0.62 dl/g. The other properties are identical to the properties of
10 the polyethylene terephthalate from Example 1 in the context of
measurement accuracy. The masterbatch employed is identical to the
masterbatch from Example 1. The process parameters and the
temperature were chosen as in Example 1. As a result of the low viscosity
of the base layer, no sheet production is possible. The three-layered melt
15 strand shows a number of flow disturbances. The stability of the melt is
inadequate.
Comparison Example 2:
A transparently colored, translucent sheet is produced analogously to
20 Example 2, the polyethylene terephthalate and masterbatch from Example
2 also being employed. The first calender roll has a temperature of 93~C
and the subsequent rolls each have a temperature of 87~C.
The sheet produced is extremely red-cloudy and almost nontransparent.
25 The light transmission, the clarity and the gloss are significantly reduced.
The sheet shows surface defects, such as bubbles, orange peel or
speckled structures. The optical properties are unacceptable for a
transparent colored application.
30 The sheet produced has the following properties profile:
- Thickness : 6 mm
- Surface gloss 1st side : inhomogeneously 70 to
CA 02261716 1999-01-29
29
(measurement angle 20~) 2nd side : inhomogeneously 70 to
- Lighttransmission : about8%to 10%
- Clarity : not measurable
- Clouding : not measurable
- Surface defects per m2 : bubbles, orange peel,
specks
(Specks, orange peel, bubbles and the like)
- Charpy impact strength an : no fracture
- Izod notched impact strength ak : 3.2 kJ/m2
- Cold forming properties : good
- Crystallinity : about 8% to 10%
- Density : 1.34g/cm3
