Specification
USE OF A FRIT CONTAINING ZINC OXIDE AS A UV PROTECTION MEANS
AND PVC SYNTHETIC MATERIAL WITH SUCH A FRIT
[0001] The invention relates to the use of a frit containing zinc oxide (ZnO) as a UV
protection means (and/or a UV protection pigment), for example an acid-stable and at the
same time (photo)catalytically inert UV protection means/pigment, in a carrier material.
[0002] Organic and inorganic UV protection means are currently used, for example
for the application in thermoplastic or thermosetting synthetic materials. The UV
protection means has the task of protecting, for example, synthetic material surfaces or
lacquer/varnish surfaces against decomposition by UV radiation in the wavelength range
of280nmto380nm.
[0003] So-called UV absorbers, quenchers and HALS may be considered as organic
UV protection means. Hydroxyphenyl benzotriazoles and hydroxybenzophenones are
primarily used as UV absorbers. In the field of quenchers, mainly nickel chelates are
used. Similarly to UV absorbers, short-wave UV radiation is converted into long-wave,
low-energy radiation also in this case. The group of HALS (Hindered Amine Light
Stabilizer) systems consists of monomeric, oligomeric and polymeric amine compounds
which deactivate radicals arising from UV radiation and hence contribute to an improved
UV stability on/at the synthetic material surface or lacquer/varnish surface. The
application of organic UV absorbers is disputed due to ineffectiveness and/or is limited to
low application concentrations due to the high costs involved.
[0004] Inorganic chemistry provides a plurality of UV protection means that can be
divided into colored or black UV absorbers and transparent or opaque UV absorbers. In
I
this regard, the group of rutile mixed phase pigments, such as Sb- and Ni-doped titanium
oxides, forms part of the colored UV absorbers, while carbon black forms part of the
black UV absorbers.
[0005] The present invention focuses on the inorganic UV absorbers, for example on
the transparent, colorless and opaque inorganic UV absorbers.
[0006] Titanium dioxide (Ti02) is the primary representative of opaque inorganic UV
absorbers. TiC>2 is for the most part used as a coated TiC>2 pigment with a rutile structure
at present. The Ti02 coating often consists of a thin inorganic layer containing Si and/or
Al, and serves to protect the surrounding matrix against the photocatalytic decomposition
which characterizes uncoated TiC>2 with anatase and a rutile structure. Alternatively or in
addition, the TiC>2 is doped with zirconium in the core. TiC>2 is an excellent absorber in
the UVB wavelength range (315 nm to 280 nm) and still a good absorber in the UVA
wavelength range (380 nm to 315 nm). Using Ti02 has the disadvantage that not 100 per
cent of the surfaces of the TiC>2 pigment particles are covered by the coating, and thus a
photocatalytically induced radical attack on the surrounding matrix of the TiC>2 particles
occurs in the case of UV radiation and a simultaneous influence of moisture. The terms
surrounding matrix or binder matrix refer to the environment of the UV absorbers or UV
protection pigments to be protected directly. Especially in case of an outdoor application
and when exposed to direct sunlight, the TiC>2 surrounding matrix is decomposed due to
the photocatalytic effect of the incompletely coated TiC>2, and a microporous, rough
surface structure is formed in the binder matrix, which simulates a change in color
intensity mainly in the case of dark color hues. The destroyed microporous structure
results in a greater scattering of the incident light than would be the case on a smooth
2
surface. The surface appears mat and brightened. This change in color intensity is also
referred to as chalking.
[0007] Due to its high refractive index of 2.7, Ti02 is for example used as a UV
protection pigment or a UV absorber for light and covering (opaque) synthetic material
and lacquer/varnish systems. In the case of dark color hues and the simultaneous
existence of the opaque Ti02 pigment, an unreasonably high color pigment application is
required to obtain a strong and color-intensive final color hue. In clear or transparent
systems, Ti02 has an opacifying effect, so that the application of Ti02 as a UV protection
pigment is not suitable in this case.
[0008] ZnO may be used as a UV protection pigment/protection means as an
alternative to or in combination with Ti02. ZnO has a better UV absorption than Ti02, in
particular in the UVA wavelength range (380 nm to 315 nm). The main disadvantage of
ZnO is its good solubility in acids. In the thermoplastic production and processing (for
example in an extruder) of, for example, PVC, HC1 vapor is released/created, which
reacts with ZnO to ZnCI2. The ZnCl2 resulting therefrom is hygroscopic and, which is
even more unfavorable, it catalyzes the thermal decomposition of PVC. Pure ZnO also
shows a photocatalytic formation of radicals, which is, however, less strong than that of
pure rutile. The intensity of the photocatalytic effect - and thus the tendency to chalking
- of pure ZnO may rather be compared to that of incompletely coated Ti02. The
refractive index of ZnO is 2.0, so that a synthetic material matrix (refractive index: 1.4 to
1.6) can be over-dyed to a color-intensive dark color system with a relatively
limited/small use of color pigments.
3
[0009] Amongst others, the following documents are known from the state of the art:
In WO 90/06974 Al, the use of water glass-coated ZnO pigments is described for the
application as an acid-proof UV protection for synthetic materials. Here, a silicate-based
coating is concerned, which encases the ZnO core material, so that there is an
inhomogeneous distribution of ZnO and the silicate-based component.
[0010] US 3 148 300 A discloses a lamp bulb made of soda-lime glass, wherein the
lamp bulb is covered with a coating containing ZnO. In order to produce the coating, a
suspension containing a frit and alcohol is deposited on the lamp bulb and then the frit is
melted onto the lamp bulb.
[0011] DE 1 496 646 A describes a finely ground frit containing Zr02 and/or Ti02
for the application field of synthetic materials, which may contain up to 15 wt% of ZnO.
It is an object of that invention to keep the opacity or the degree of whiteness high despite
the siliceous dilution.
[0012] Glass frits having a similar composition are, for example, known from EP 1
870 383 Al, EP 1 298 099 Al, US 5 618 764, and US 4 493 900. However, these known
frits have not been used as a UV protection pigment so far.
[0013] A frit is understood as molten glass already solidified and ground again,
which may have crystalline component parts in addition to amorphous parts. The frit
according to the invention may consist of network formers, such as Si02 or B2O3,
network modifiers, such as alkali oxides or alkaline earth oxides, and ZnO and, as the
case may be, intermediate oxides, such as AI2O3 (which may act both as network
modifiers and as network formers). An amorphous glass phase is produced by melting the
network formers, network modifiers and intermediate oxides. For a preparation of mat
4
frits, different opacifying agents, such as Ti02, Sn02, Zr02, Ce02 and Ca3(P04)2 and
Na3AlF6 are used in addition. The opacifying agents are predominantly exposed and are
not provided as part of the network of the glass phase in the glass. Oxides or mixed
oxides may be crystallized from the amorphous glass phase by an additional tempering
step.
[0014] The invention aims at providing a cost-effective and efficient/effective UV
protection means (for example a UV protection pigment), for example a UV absorber for
protecting the surrounding matrix against destructive UV radiation.
[0015] For this purpose, the invention suggests the use of a frit containing ZnO as
described in claim 1. Further embodiments of the use according to the invention are
described in the dependent claims. Claim 11 describes the advantageous use of the frit in
PVC, or rather the PVC synthetic material resulting therefrom, in which the frit is
distributed.
[0016] In this respect, the inventor has found a solution to integrate ZnO as a
chemically and mechanically stable UV light absorbing protective means/pigment into a
binder matrix.
[0017] Surprisingly, it has been found out that ZnO bound in a frit comprises an
excellent UV light absorption and at the same time proves itself to be acid-proof and
abrasion-proof as well as photocatalytically inert with respect to the surrounding matrix.
In this context, the ZnO is provided in a crystalline form in the frit and/or as a part of the
network of the glass phase.
[0018] The above-described problem is, for example, solved by a frit that is, in
addition to 20 wt% to 75 wt% of ZnO, further composed of:
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• 5 wt% to 85 wt%, for example 5 wt% to 80 wt% of at least one network
former from the oxides of the group of Si02, B2O3 and P2O5,
• 0.05 wt% to 50 wt% of at least one network modifier from the oxides of the
group of BaO, CaO, SrO, K20, Na20 and Li20,
• 0 wt% to 50 wt%, for example 5 wt% to 50 wt% of at least one intermediate
oxide from the oxides of the group of Ai2C>3, V2O5, Fe2C>3 and MgO, as well as
• 0 wt% to 50 wt% of one or more opacifying agents from the oxides of the
group of Ti02, Sn02 and Zr02, Ce02 as well as Ca3(P04)2 and Na3AlF6.
[0019] The ZnO concentration in the frit may, for example, be greater than 30 wt%,
for example greater than 50 wt%.
[0020] The ZnO containing frit incorporated in a synthetic material matrix as a
protection means or pigment protects the surrounding matrix by the irradiated highenergy
UV light being predominantly absorbed and converted into thermal radiation with
a longer wavelength and emitted by the frit containing ZnO. The fraction of the UV light
reflected or scattered on the frit containing ZnO is, for example, low, so that there is no
additional stress by radiation to the surrounding matrix by reflection or scattering on the
frit containing ZnO. The transmission of the UV light is, for example, low as well.
[0021] The absorption effect is, on the one hand, achieved by the ZnO in its function
as a network modifier interrupting the siliceous framework so strongly that there is a shift
of the UV absorption to higher wavelength ranges in comparison to normal borosilicate
or soda-lime glasses. In contrast, pure quartz glass, as a representative of an undisturbed
siliceous network, has no UV absorption and is therefore to be considered as being UV
6
transparent. On the other hand, ZnO particles undissolved in the glass phase or
recrystallized absorb UV light due to the semiconductor property of ZnO.
[0022] A potentially occurring scattering of the UV light on/at the crystalline ZnO
particles opacifies the frit, but does not contribute to protecting the surrounding matrix.
[0023] When being incorporated into PVC, the frit containing ZnO results in a
comparatively significantly smaller tendency to chalking than it is, for example, the case
with pure ZnO or in comparison to different qualities of coated T1O2, as well as to BaS04
or other frits containing zirconium.
[0024] The frit containing ZnO may be produced in accordance with known methods
by mixing and melting predominantly oxidic or siliceous raw materials, and by
subsequently cooling and grinding the frozen melt. Moreover, an additional tempering
process may follow or may be interposed, with the aim to induce a recrystallization of
ZnO. An exemplary average/mean crystallite size of the recrystallized or undissolved
ZnO particles in the frit is, for example, less than 300 nm, for example less than 100 nm.
The resulting mean/average grain size of the frit after grinding, in relation to the particle
number, is less than 5 um, for example less than 1 um according to the invention. The
burning temperature during the melting process may be between 600°C and 1,400°C, for
example between 900°C and 1,200°C. The optional tempering occurs, for example, at
temperatures of 400°C to 900°C.
[0025] For preparing the frit, ZnO qualities are, for example, used, which include a
maximum of 1 wt% of impurities and have a sieve retention of less than 0.05 wt% with a
mesh size of 42 um. The qualities are, amongst others, also known from the product
names "red seal", "green seal", and "white seal". Other raw material used are, for
7
example, commercially available oxides, silicates, borates, carbonates or fluorides, such
as feldspars, quartz powder, kaolin, zirconium silicate, rutile, calcspar, barium carbonate,
bone ashes, cryolite or fluorite, etc. The use as a powder with a mean grain size of less
than 100 urn may be mentioned as an example.
[0026] The color of the frit is, for example, white or colorless, depending on the
system in which the observation takes place. When exposed to air, the color is, for
example, white, a degree of whiteness of more than 90% being aimed for in the CieL*a*b
measuring system. Both the a value (yellow blue axis) and the b value (green red axis)
are, for example, between -4 and +4 points.
[0027] If the frit is, for example, incorporated into the synthetic material PVC, the
degree of whiteness strongly decreases when compared to the observation when exposed
to air, and the total system of PVC and the frit containing ZnO appears almost
transparent. This is caused by the refractive indices of PVC and the frit containing ZnO.
The refractive index of the frit containing ZnO lies between 1.4 and 2.6, for example
between 1.5 and 2.0. The synthetic material matrix or lacquer/varnish matrix mostly has a
refractive index of 1.4 to 1.6. The total system of the frit containing ZnO and the
synthetic material matrix or lacquer/varnish matrix appears transparent, if both refractive
indices are the same, and appears slightly opaque, if the refractive index of the frit
containing ZnO is greater than the refractive index of the surrounding synthetic material
matrix. For example, the a and b value change in the CieL*a*b measuring system (yellow
blue axis) is changed to a maximum of between -6 and +6 points by incorporating the frit
containing ZnO into the synthetic material or lacquer/varnish matrix.
8
[0028] The inventive range of application of the frit containing ZnO includes PVC,
PMMA, ASA, WPC, PP, PE, PS, EVA, PIB, PC and ABS.
[0029] The frit containing ZnO may be used alone or in combination with
conventional organic or inorganic pigments, and also may be mixed with colorants and
fillers as well as with various synthetic material stabilizers or solvents. For example, the
frit containing ZnO may be mixed with Ti02, whereby a UV broadband filter for UVA
and UVB radiation can be generated. In this respect, there is no limitation to a specific
mixing ratio. In the case of the synthetic material PVC, synthetic material stabilizers are
understood as being the additives necessary for the thermoplastic shaping, such as
thermostabilizers, softeners, acid scavengers, lubricants and antioxidant agents, whereas
fillers refer to calcspar, heavy spar, talcum or kaolin. The polycyclic pigments, such as
copper phthalocyanines, quinacridones, pyrrol pyrrols, isoindolines, perylenes and azo
pigments, such as diaryl yellow and benzimidazolones, are typical representatives of
organic pigments. The most important representatives of inorganic pigments are iron
oxides, rutile mixed phase pigments, soot, ultramarines, chromium oxide green as well as
a wide range of mixed oxide pigments. Representatives of colorants are, for example,
anthrachinons, methines, perinones and anthrapyridones.
[0030] In this respect, the frit containing ZnO may be incorporated into the target
area of application directly as a powder component or mixed with other materials or as a
concentrate in the form of a so-called master batch. A master batch is a premix or (color)
concentrate, substantially consisting of 40 wt% to 90 wt% of a pigment or a pigment
mixture, and 60 wt% to 10 wt% of a synthetic material mixture and/or a wax mixture or
of a solvent, including water and organic solvents.
9
[0031] The application concentration of the frit containing ZnO in the inventive areas
of application is, for example, greater than 0.01 wt% and less than 90 wt%, for example
between 0.1 wt% and 10 wt%, and, for example between 0.2 wt% and 6 wt%.
[0032] The incorporation of the UV absorbing frit containing ZnO as a UV protection
additive into dark colored synthetic materials or lacquers/varnishes with an L value of
less than 85 points in the CieL*a*b measuring system is recommendable, as the chalking
effect otherwise occurring in this case would be visible in a particularly strong way.
[0033] The frit containing ZnO is characterized by a low solubility in diluted acids
and alkalis. Due to the at least partial incorporation of ZnO into the ceramic network, this
characteristic of low solubility in acids and alkalis is maintained even after intensive
abrasive mixing. In addition, the frit containing ZnO is resistant to temperatures of up to
at least 300°C.
[0034] Example:
[0035] A) Production of the frit containing ZnO
A ZnO containing frit having the following composition:
6.5 wt% K20
50.9 wt% ZnO
7.1 wt%Al203
35.5 wt% Si02
is produced by mixing 73.3 g ZnO powder, 55.6 g potassium feldspar powder
(K20 * A1203 * 6 Si02) and 12 g quartz powder (Si02) and by subsequent
burning/baking at 1,100 °C, quenching in a water bath and subsequent
grinding in an impact mill to an average grain size diameter of dso < 1 jam.
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The XRD analysis of the frit containing ZnO showed crystalline parts of
ZnO.
[0036] B) Use of the frit containing ZnO as a UV protection pigment
1 wt% of the frit containing ZnO produced under item A is incorporated
together with 2 wt% of a light-fast and weather-resistant dark brown pigment
preparation with the following composition:
- Sicopal brown K 2795 (chromite/ferrochrome brown) 84.5 wt%
- PV genuine brown HFR (benzimidazolone) 8.8 wt%
- Monarch 800 (carbon black) 6.7 wt%
a) into a lead-stearate-stabilized and
b) into acalcium-zinc-stearate-stabilized
PVC window profile formulation
The incorporation occurs by means of rolling the pigment frit PVC mixture
for 2 minutes at 180°C on the calendar roll and by subsequently pressing the
rolled sheet to a press plate at 190°C and with a holding time of 90 seconds.
[0037] C) Pigments of comparison
Corresponding to the method under item B, for the purpose of comparison, 1
wt% of each of the following conventional inorganic UV protection pigments
is used together with 2 wt% of the dark brown pigment preparation in the
different window profile formulations:
1. Ti02 Kronos 2220
2. Ti02 Kronos 2057
11
3. ZnO, quality: white seal
4. ZrSi04 335
5. ZnO containing frit with a ZnO content of 5.6 wt%.
Moreover, 1 wt% of BaS04 EWO was used together with 2 wt% of the dark
brown pigment preparation in the different window profile formulations as a
zero sample.
[0038) D) QUV test
With the press plates prepared under items B and C, the so-called QUV test in
accordance with DIN EN ISO 4892-3, method A, cycle number 1 was carried
out.
In this context, the press plates are alternately irradiated with UV light with
the wavelength of 300 nm to 400 nm (maximum irradiation of 340 nm) for 8
hours and exposed to condensed water for 4 hours without irradiation.
After 500 hours already, in the lead-stabilized synthetic material window
matrix, the frit containing ZnO according to A shows a significant superiority
relative to the other samples. The sample with the frit containing ZnO
according to A visually shows no chalking, while all other samples already
clearly show chalking. After 2,000 hours, chalking is visible in all press
plates and synthetic material window matrixes, but the extent of chalking is
significantly lower in the sample plate with the frit containing ZnO according
to A when compared to all other samples.
The press plates C5, which only had a ZnO content of 5.6 wt% in the frit,
12
showed a considerable/clear degree of chalking, comparable to the samples
with the coated Ti02 according to CI and C2.
[0039] E) Test as to acid stability
4 wt% of the frit containing ZnO produced under item A were added to a
calcium-zinc-stabilized PVC window profile formula and rolled on the
calendar roll at 180°C, until destruction of the PVC occurs. The same
procedure was carried out for a zero sample without a ZnO containing frit and
for a sample with 4 wt% of ZnO of the white seal quality.
The destruction of the PVC by permanent rolling at 180°C is, in this
experiment, characterized by a separation of the rolled sheet from the hot
calendar roll.
Result:
Sample
Zero sample
Frit containing 4 wt% of ZnO
4 wt% of ZnO white seal
Rolling time until PVC is destroyed
38 minutes
38 minutes
25 minutes
The frit containing ZnO acts in an unchanged manner compared to the zero
sample. In contrast, the application of pure, unprotected ZnO of the white seal
quality accelerates the PVC's degradation.
13
Claims
What is claimed is:
1. Use of a zinc-oxide containing frit with a ZnO content of 20 wt% to 75 wt% and
an average grain size, related to the particle number, of less than 5 \xm as a UV light
absorbing UV protection means in PVC, PMMA, ASA, WPC, PP, PE, PS, EVA, PIB, PC
orABS.
2. Use of a frit containing ZnO according to claim 1, characterized in that the frit
containing ZnO is, in addition to 20 wt% to 75 wt% of ZnO, further composed of:
• 5 wt% to 80 wt% of at least one network former from the oxides of the group
ofSi02,B203andP205,
• 0.05 wt% to 50 wt% of at least one network modifier from the oxides of the
group of BaO, CaO, SrO, K20, Na20 and Li20,
• 0 wt% to 50 wt%, for example 5 wt% to 50 wt%, of at least one intermediate
oxide from the oxides of the group of Al203, V2O5, Fe203 and MgO, as well as
• 0 wt% to 50 wt% of one or more opacifying agents from the oxides of the
group of Ti02, Sn02 and Zr02, Ce02 as well as Ca3(P04)2 and Na3AIF6.
3. Use of a frit containing ZnO according to any of claims 1 to 2, characterized in
that the average grain size is less than 1 urn.
4. Use of a frit containing ZnO according to any of claims 1 to 3, characterized in
that the degree of whiteness of the frit measured against air as environmental medium,
expressed by the L value in the CieL*a*b measuring system, is greater than 90 points.
14
5. Use of a frit containing ZnO according to any of claims 1 to 4, characterized in
that the frit containing ZnO is prepared by melting commercially available oxides,
silicates, borates, carbonates or fluorides, such as zinc oxide, feldspars, quartz powder,
soda, zirconium silicate, rutile, calcspar, barium carbonate, cryolite etc., at 600 °C to
1,400 °C, by cooling, by optionally tempering again, and by grinding.
6. Use of a frit containing ZnO according to any of claims 1 to 5, characterized in
that the ZnO is provided in a crystalline form and/or as a component part of the network
of the glass phase in the frit.
7. Use of a frit containing ZnO according to claim 6, characterized in that the
crystalline ZnO of the frit has an average crystallite size of less than 300 nm, for example
of less than 100 nm.
8. Use of a frit containing ZnO according to any of claims I to 7, characterized in
that the application concentration of the frit containing ZnO in the carrier material is
greater than 0.01 wt% and less than 90 wt%, for example between 0.1 wt% and 10 wt%,
for example between 0.2 wt% and 6 wt%.
9. Use of a frit containing ZnO according to any of claims 1 to 8, characterized in
that the frit containing ZnO is used as a UV protection means in a dark colored synthetic
material or lacquer/varnish with an L value in the CieL*a*b measuring system of less
than 85 points.
10. Use of a frit containing ZnO according to any of claims 1 to 9, characterized in
that the ZnO concentration in the frit is greater than 30 wt%, for example greater than
50 wt%.
15
11. PVC synthetic material, into which a zinc-oxide containing frit with a ZnO
content of 20 wt% to 75 wt% and an average grain size, related to the particle number, of
less than 5 urn is incorporated as a UV light absorbing UV protection means.
12. PVC synthetic material according to claim 11, wherein the concentration of the
frit containing ZnO is greater than 0.01 wt% and less than 90 wt%, for example between
0.1 wt% and 10 wt%, for example between 0.2 wt% and 6 wt%.
13. PVC synthetic material according to claim 11 or 12, wherein the average grain
size of the frit containing ZnO is less than 1 um.
14. PVC synthetic material according to any of claims 11 to 13, wherein the degree of
whiteness of the frit, measured against air as environmental medium, expressed by the L
value in the CieL*a*b measuring system, is greater than 90 points.
15. PVC synthetic material according to any of claims 11 to 14, wherein the PVC
synthetic material has an L value in the CieL*a*b measuring system of less than 85
points.
16. PVC synthetic material according to any of claims 11 to 15, wherein the ZnO is
provided in a crystalline form and/or as a component part of the network of the glass
phase in the frit.
17. PVC synthetic material according to claim 16, wherein the crystalline ZnO of the
frit has an average crystallite size of less than 300 nm, for example of less than 100 nm.
16
18. PVC synthetic material according to any of claims 11 to 17, wherein the ZnO
concentration in the frit is greater than 30 wt%, for example greater than 50 wt%.
Daled this the 5th day of June 2014.
r^
J
(H. SUBRAMANIAM)
O/SUBRAMANIAM & ASSOCIATES
Attorneys for the applicants
17
ABSTRACT
USE OF A FRIT CONTAINING ZINC OXIDE AS A UV PROTECTION MEANS AND
PVC SYNTHETIC MATERIAL WITH SUCH A FRIT
The invention describes the use of a zinc oxide containing frit with a ZnO content of
20 wt% to 75 wt% and an average grain size of less than 30 urn as a UV light absorbing UV
protection means, for example for the application areas of thermoplastically deformable synthetic
materials, solvent-containing and water-containing lacquers/varnishes, radiation-curing lacquers/
varnishes, powder lacquers/varnishes, paper coatings and hydraulic-setting construction
products.
(12) NACH DEM VERTRAG UBER DIE INTERNATIONALE ZUSAMMENARBEIT AUF DEM GEBIET DES
PATENTWESENS (PCT) VEROFFENTLICHTE INTERNATIONALE ANMELDUNG
(19) Weltorganisation fur geistiges
Eigentura
Internationales Buro
(43) Internationales
Veroffenttichun gsdatum
13. Juni 2013 (13.06.2013) WIPOI PCT
III
(10) Internationale Verbffentlichungsnummer
WO 2013/083439 Al
(51) Internationale Patentklassifikation:
C0SK3/00 (2006.01) C09D S/32 (2006.01)
C08K3/22 (2006.01) C09D 7/12(2006.01)
C08L 27/06 (2006.01) C09D 127/06 (2006.01)
(21) Internationales Aktenzeichen: PCT/EP2012/073746
(22) Internationales Anmeldedatum:
27. November 2012 (27.11.2012)
(25) Elnrelchungssprache:
(26) Veroff en tlichuugssprache:
Deutsch
Deutsch
(30) Angaben zur Prioritat:
10 2011 120 174.6
6.Dezember2011 (06.12.2011) DE
102012 004 138.1
14. Februar 2012 (14.02.2012) DE
(71) Anmelder: LEY & CO. FARBENWERKE
WUNSIEDEL KG [DE/DE]; Goethestr. 58, 95615
Marktredwitz-Brand (DE).
(72) Erfinder: NURNBERGER, Michael; Goethestr. 58,
95615 Marktredwitz-Brand (DE).
(74) Anwalt: KtfHN, Armln; Viering, Jentschura & Partner,
Grillparzerstr. 14, 81675 Miinchen(DE).
(81) Besdmraungsstaaten (soweit nicht anders angegeben, jur
jede verfugbare nationale Schutzrechtsart): AE, AG, AL,
AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW,
BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK,
DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM,
GT, HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN,
KP, KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD,
ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI,
NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, RU,
RW, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ,
TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA,
ZM,ZW.
(84) Bestimmungsstaaten (soweit nicht anders angegeben, jur
jede verfugbare regionale Schutzrechtsart): ARTPO (BW,
GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, SZ,
TZ, UG, ZM, ZW), eurasisches (AM, AZ, BY, KG, KZ,
RU, TJ, TM), europaisches (AL, AT, BE, BG, CH, CY,
CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT,
LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE,
SL SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA,
GN, GQ, GW, ML, MR, NE, SN, TD, TG).
VerSffcntlicht:
— mit internationalem Recherchenbericht (Artikel 21 Absatz
3)
— vor Ablauf der jur Anderungen der Anspriiche gehenden
Frist; Verqffentlichung wird wiederholt, falls Anderungen
eingehen (Kegel 48 Absatz 2 Buchstabe h)
rH (54) Title: USE OF A ZINC-OXIDE-CONTAINING FRIT AS A UV PROTECTION MEANS AND PVC PLASTIC HAVING
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(54) Bezeichnung : VERWENDUNG EINER
KUNSTSTOFF MIT EINER SOLCHEN FRITTE
ZINKOXIDHALTIGEN FRITTE ALS UV-SCHUTZMITTEL UND PVC-
(57) Abstract: The invention relates to the use of a zinc-oxide-containing frit, having a ZnO content of 20 to 75% by weight and an
average grain size of less than 30 pm, as a UV-light-absorbing UV protection means for e.g. applications in thennoplasticaUy
deformable plastics, solvent- and water-containing and radiation-curing paints, powder paints, paper coatings, and hydraulically
bound construction products.
(57) Zusammenfassung: Die Erfindung beschreibt die Verwendung einer zinkoxidhaltigen Fritte mit einem ZnO- Gehait von 20 bis
75 Gew.% und einer mittleren KomgrofJe von weniger als 30 jim als UV-Licht absorbierendes UV-Schutzmittel fur z.B. die
Einsatzbereiche thermoplastisch verformbare Kunststoffe, losemittel- und wasserhaltige sowie Strahlungshartende Lacke,
Pulverlacke, Papierbeschichtungen und hydraulisch abbindende Bauprodukte.
r
• • . /
ear
pr Ais in Bayern offentlich bestellte und allgemein beeidigte Obersetzerin fur die englische
f Sprache bestatige ich:
Vorstehende Obersetzung der mir in deutscher Sprache vorgelegten, ursprunglich
eingereichten Fassung der PCT-Anmeldung PCT/EP2012/073746 mit dem Titel
„Verwendung einer zinkoxidhaltigen Fritte als UV-Schutzmittel und PVC-Kunststoff mit
einer solchen Fritte" ist richtig und voilstandig.
In my capacity as a translator for the English language, duly appointed, commissioned
and sworn in by the President of the Munich Regional Court, f hereby certify that the
foregoing is a true and complete English translation of the originally filed version of PCT
application PCT/EP2012/073746 with the title ..Verwendung einer zinkoxidhaltigen Fritte
als UV-Schutzmittel und PVC-Kunststoff mit einer solchen Fritte" submitted to me in the
German language.
[AS ORIGINALLY FILED AND PUBLISHED]
USE OF A FRIT CONTAINING ZINC OXIDE AS A UV PROTECTION MEANS
AND PVC SYNTHETIC MATERIAL WITH SUCH A FRIT /
[00011 The invention relates to the use of a frit containing zinc oxide (ZnO) as ar UV
protection means (and/or a UV protection pigment), for example an acid-stable and at the
same time (photo)catalytically inert UV protection means/pigment, in a carrier material,
for example in synthetic material systems and lacquer/vamish systems. /
[0002] Organic and inorganic UV protection means are currently ysed, for example
for the application in thermoplastic or thermosetting synthetic materials. The UV
protection means has the task of protecting, for example, synthetic material surfaces or
lacquer/vamish surfaces against decomposition by UV radiatfon in the wavelength range
of280nmto380nm. /
[0003] So-called UV absorbers, quenchers and H/CLS may be considered as organic
UV protection means. Hydroxyphenyl benzotriazoles and hydroxybenzophenones are
primarily used as UV absorbers. In the field of/quenchers, mainly nickel chelates are
used. Similarly to UV absorbers, short-wavp UV radiation is converted into long-wave,
low-energy radiation also in this case. TKe group of HALS (Hindered Amine Light
Stabilizer) systems consists of monoi^neric, oHgomeric and polymeric amine compounds
which deactivate radicals arising from UV radiation and hence contribute to an improved
UV stability on/at the synthetic material surface or lacquer/varnish surface. The
application of organic UV-absorbers is disputed due to ineffectiveness and/or is limited to
low application concentrations due to the high costs involved.
1
[0004] Inorganic chemistry provides a plurality of UV protection means that car/be
divided into colored or black UV absorbers and transparent or opaque UV absorbers. In
this regard, the group of rutile mixed phase pigments, such as Sb- and Ni-dopea titanium
oxides, forms part of the colored UV absorbers, while carbon black forms nart of the
black UV absorbers. /
[0005] The present invention focuses on the inorganic UV absorbers, for example on
the transparent, colorless and opaque inorganic UV absorbers. /
[0006] Titanium dioxide (T1O2) is the primary representative of opaque inorganic UV
absorbers. T1O2 is for the most part used as a coated Ti02 pigment with a rutile structure
at present. The TiC>2 coating often consists of a thin inorganic layer containing Si and/or
Al, and serves to protect the surrounding matrix agains/the photocatalytic decomposition
which characterizes uncoated TiCh with anatase and/a rutile structure. Alternatively or in
addition, the Ti02 is doped with zirconium in the^ore. TiOi is an excellent absorber in
the UVB wavelength range (315 nm to 280 nm) and still a good absorber in the UVA
wavelength range (380 nm to 315 nm). Usirfg Ti02 has the disadvantage that not 100 per
cent of the surfaces of the TiC>2 pigmentparticles are covered by the coating, and thus a
photocatalytically induced radical attack on the surrounding matrix of the TiC>2 particles
occurs in the case of UV radiation/nd a simultaneous influence of moisture. The terms
surrounding matrix or binder matrix refer to the environment of the UV absorbers or UV
protection pigments to be protected directly. Especially in case of an outdoor application
and when exposed to direox sunlight, the Ti02 surrounding matrix is decomposed due to
the photocatalytic effec/of the incompletely coated TiC>2, and a microporous, rough
surface structure is formed in the binder matrix, which simulates a change in color
2
intensity mainly in the case of dark color hues. The destroyed microporous structure;
results in a greater scattering of the incident light than would be the case on a smooth
surface. The surface appears mat and brightened. This change in color intens^y is also
referred to as chalking. /
[0007] Due to its high refractive index of 2.7, TiC>2 is for exampleyused as a UV
protection pigment or a UV absorber for light and covering (opaqu«0 synthetic material
and lacquer/varnish systems. In the case of dark color hues andifie simultaneous
existence of the opaque T1O2 pigment, an unreasonably high/color pigment application is
required to obtain a strong and color-intensive final color/nue. In clear or transparent
systems, TiC>2 has an opacifying effect, so that the application of TiC>2 as a UV protection
pigment is not suitable in this case. /
[0008] ZnO may be used as a UV protection! pigment/protection means as an
alternative to or in combination with Ti(>2. #nO has a better UV absorption than T1O2, in
particular in the UVA wavelength range jp80 nm to 315 nm). The main disadvantage of
ZnO is its good solubility in acids. Inytne thermoplastic production and processing (for
example in an extruder) of, for example, PVC, HC1 vapor is released/created, which
reacts with ZnO to ZnCl2. The/nCI2 resulting therefrom is hygroscopic and, which is
even more unfavorable, it catalyzes the thermal decomposition of PVC. Pure ZnO also
shows a photocatalytic formation of radicals, which is, however, less strong than that of
pure rutile. The intensity of the photocatalytic effect - and thus the tendency to chalking
- of pure ZnO ma/rather be compared to that of incompletely coated Ti02. The
refractive inde/of ZnO is 2.0, so that a synthetic material matrix (refractive index: 1.4 to
3
1.6) can be over-dyed to a color-intensive dark color system with a relatively .
limited/small use of color pigments. /
[00091 Amongst others, the following documents are known from the state/w the art:
In WO 90/06974, the use of water glass-coated ZnO pigments is described fior the
application as an acid-proof UV protection for synthetic materials. Here,/silicate-based
coating is concerned, which encases the ZnO core material, so that there is an
inhomogeneous distribution of ZnO and the silicate-based component.
[0010] DE 1 496 646 A describes a finely ground frit containing Zr02 and/or HO2
for the application field of synthetic materials, which may contain up to 15 wt% of ZnO.
It is an object of that invention to keep the opacity or the degree of whiteness high despite
the siliceous dilution. /
[0011] Glass frits having a similar composition ace, for example, known from EP 1
870 383 Al, EP 1 298 099 Al, US 5 618 764, and>US 4 493 900. However, these known
frits have not been used as a UV protection pign/ent so far.
[0012] A frit is understood as molten glass already solidified and ground again,
which may have crystalline component pans in addition to amorphous parts. The frit
according to the invention may consistpf network formers, such as Si02 or B2O3,
network modifiers, such as alkali oxides or alkaline earth oxides, and ZnO and, as the
case may be, intermediate oxides,/such as AI2O3 (which may act both as network
modifiers and as network formers). An amorphous glass phase is produced by melting the
network formers, network modifiers and intermediate oxides. For a preparation of mat
frits, different opacifying-agents, such as Ti02, Sn02, Zr02, Ce02 and Ca3(P04)2 and
Na3AlF6 are used in adyaition. The opacifying agents are predominantly exposed and are
4
not provided as part of the network of the glass phase in the glass. Oxides or mfed
oxides may be crystallized from the amorphous glass phase by an additional/tempering
step. /
[0013] The invention aims at providing a cost-effective and efficient/effective UV
protection means (for example a UV protection pigment), for example a UV absorber for
protecting the surrounding matrix against destructive UV radiatidn, for example for use
in a thermoplastic or thermosetting synthetic material. /
[0014] For this purpose, the invention suggests the use M a frit containing ZnO as
described in claim 1. Further embodiments of the use according to the invention are
described in the dependent claims. Claim 12 describe/the advantageous use of the frit in
PVC, or rather the PVC synthetic material resulting therefrom, in which the frit is
distributed. /
[0015] In this respect, the inventor has found a solution to integrate ZnO as a
chemically and mechanically stable UV lij^ht absorbing protective means/pigment into a
binder matrix of, for example, thermoplastic or thermosetting synthetic material,
[0016] Surprisingly, it has been round out that ZnO bound in a frit comprises an
excellent UV light absorption and/at the same time proves itself to be acid-proof and
abrasion-proof as well as photocatalytically inert with respect to the surrounding matrix.
In this context, the ZnO is provided in a crystalline form in the frit and/or as a part of the
network of the glass phasj6.
[0017] The abovendescribed problem is, for example, solved by a frit that is, in
addition to 20 wt%p 75 wt% of ZnO, further composed of:
5
• 5 wt% to 85 wt%, for example 5 wt% to 80 wt% of at least one netwo/k
former from the oxides of the group of S1O2, B2O3 and P2O5, /
• 0.05 wt% to 50 wt% of at least one network modifier from the o/ides of the
group of BaO, CaO, SrO, K20, Na20 and Li20, /
• 0 wt% to 50 wt%, for example 5 wt% to 50 wt% of at leas/one intermediate
oxide from the oxides of the group of AI2O3, V2O5, Fe2C>3 and MgO, as well as
• 0 wt% to 50 wt% of one or more opacifying agents from the oxides of the
group of T1O2, Sn02 and Zr02, Ce02 as well as Ca3(R04)2 and Na3AlF6.
[0018] The ZnO concentration in the frit may, for exar/ple, be greater than 30 wt%,
for example greater than 50 wt%. /
[0019] The ZnO containing frit incorporated in a>aiermoplastic or thermosetting
synthetic material matrix as a protection means or .pigment protects the surrounding
matrix by the irradiated high-energy UV light b/ing predominantly absorbed and
converted into thermal radiation with a longer wavelength and emitted by the frit
containing ZnO. The fraction of the UV light reflected or scattered on the frit containing
ZnO is, for example, low, so that there is no additional stress by radiation to the
surrounding matrix by reflection or scattering on the frit containing ZnO. The
transmission of the UV light is, for example, low as well.
|0020] The absorption effect is, on the one hand, achieved by the ZnO in its function
as a network modifier interrupting the siliceous framework so strongly that there is a shift
of the UV absorption to higher wavelength ranges in comparison to normal borosilicate
or soda-lime glasses. Ir/contrast, pure quartz glass, as a representative of an undisturbed
siliceous network, h/s no UV absorption and is therefore to be considered as being UV
6
transparent. On the other hand, ZnO particles undissolved in the glass phase or /
recrystallized absorb UV light due to the semiconductor property of ZnO. /
[0021] A potentially occurring scattering of the UV light on/at the crysta/line ZnO
particles opacifies the frit, but does not contribute to protecting the surrou/ding matrix.
[0022] When being incorporated into PVC, the frit containing ZnO/results in a
comparatively significantly smaller tendency to chalking than it is, fi»r example, the case
with pure ZnO or in comparison to different qualities of coated TL02, as well as to BaS04
or other frits containing zirconium. /
[0023] The frit containing ZnO may be produced in accordance with known methods
by mixing and melting predominantly oxidic or siliceous raw materials, and by
subsequently cooling and grinding the frozen melt. Moreover, an additional tempering
process may follow or may be interposed, with the aim to induce a recrystallization of
ZnO. An exemplary average/mean crystallite size>of the recrystallized or undissolved
ZnO particles in the frit is, for example, less than 300 nm, for example less than 100 nm.
The resulting mean/average grain size of the/frit after grinding, in relation to the particle
number, should be less than 30 ^m, for example less than 5 urn, and for example less
than 1 \im. The burning temperature during the melting process may be between 600°C
and 1,400°C, for example between 900°C and 1,200°C. The optional tempering occurs,
for example, at temperatures of 400°C to 900°C.
[0024] For preparing the frit, ZnO qualities are, for example, used, which include a
maximum of 1 wt% of impunities and have a sieve retention of less than 0.05 wt% with a
mesh size of 42 um The equalities are, amongst others, also known from the product
names "red seal", "green seal", and "white seal". Other raw material used are, for
7
example, commercially available oxides, silicates, borates, carbonates or fluorides, such
as feldspars, quartz powder, kaolin, zirconium silicate, ruttle, calcspar, bariun/carbonate,
bone ashes, cryolite or fluorite, etc. The use as a powder with a mean grair/size of less
than 100 u.m may be mentioned as an example. /
[0025] The color of the frit is, for example, white or colorless, depending on the
system in which the observation takes place. When exposed to ain( the color is, for
example, white, a degree of whiteness of more than 90% beins4imed for in the CieL*a*b
measuring system. Both the a value (yellow blue axis) and the b value (green red axis)
are, for example, between -4 and +4 points. /
[0026] If the frit is, for example, incorporated int3 and MgO, as well as /
• 0 wt% to 50 wt% of one or more opacifying agents from the oxides of the
group of TiC>2, Sn02 and ZrC>2> Ce02 as well as Ca3(P04)2 and W^AlFe.
[0042] Alternatively or in addition, the mean grain size mayyfor example, be less
than 5 urn and, for example, less than I urn. /
[0043] Alternatively or in addition, the degree of whjteness measured against air as
environmental medium, expressed by the L value in (CieL*a*b, may be greater than 90
points when using the frit containing ZnO. /
[0044] Alternatively or in addition, whej/using the frit containing ZnO, the frit
containing ZnO may be prepared by mebmg standard oxides, silicates, borates,
carbonates or fluorides, such as zine/>xide, feldspars, quartz powder, soda, zirconium
silicate, rutile, calcspar, barium oarbonate, cryolite, etc. at 600 °C to 1,400 °C, by cooling
and, as the case may be, by tampering again and by grinding.
[0045] Alternatively/or in addition, the ZnO may exist in a crystalline form and/or as
a component part ofjme network of the glass phase in the frit, when using the frit
containing ZnOJ
[0046] Afternatively or in addition, the crystalline ZnO of the frit may have a
mean/avj^rage crystallite size of less than 300 nm and, for example, of less than 100 nm,
whepi using the frit containing ZnO.
[0047] When using the frit containing ZnO, the application concentration of the frit
containing ZnO may alternatively or in addition be greater than 0.01 wt% and less than
15
90 wt%, for example between 0.1 wt% and 10 wt%, and for example between 0.2
and 6 wt%, in the inventive areas of application. /
[0048] When using the frit containing ZnO, the frit containing ZnO may/
alternatively or in addition, be used as a UV protection pigment in dark colored synthetic
materials or lacquers/varnishes with an L value in the CieL*a*b measuring system of less
than 85 points. /
[0049] Alternatively or in addition, when using the frit containing ZnO, the frit
containing ZnO may be used in thermoplastically deformable synthetic materials, such as
PVC, PMMA, ASA, WPC, PP, PE, PS, EVA, PIB, PC and ABS, solvent-based lacquers/
varnishes, such as alkyd resin lacquers/varnishes/polyester paints, epoxy resin lacquers/
varnishes, polyurethane resin lacquers/varnishes, paints and lacquers/varnishes on the
basis of acrylic polymers, polystyrene lacquers/varnishes and polyvinyl resin lacquers/
varnishes, water-based lacquers/varmshes, such as dispersion paints, dispersion lacquer/
varnish paints, groundings and coating agents, radiation-curing lacquer/varnish systems,
powder lacquer/varnish systems, paper coatings and other paints based on synthetic and
natural polymers, as welLas in hydraulic-setting construction products, such as joint
compounds, cements-and plasters.
[0050] According to yet another embodiment of the invention, a zinc oxide
containing frfrwith a ZnO content of 20 wt% to 75 wt% and a mean/average grain size of
less than 30 u.m may be used as a UV light absorbing pigment for the application areas of
thermoplastically deformable synthetic materials, thermosetting synthetic materials,
solvent-based lacquers/varnishes, water-based lacquers/varnishes, radiation-curing
lacquers/varnishes and lacquer/varnish systems, powder lacquers/varnishes and powder
16
lacquer/varnish systems, other carrier materials on the basis of synthetic and natunal
polymers or waxes, paper coatings and hydraulic-setting construction product/
[0051] In this respect, the frit containing ZnO may, in addition to 20 Wt% to 75 wt%
of ZnO, further be composed of: /
• 5 wt% to 80 wt% of at least one network former fronyme oxides of the group
of Si02, B203, and P205, /
• 0.05 wt% to 50 wt% of at least one network ptfodifier from the oxides of the
group of BaO, CaO, SrO, K20, Na20, and Li2Cy
• 0 wt% to 50 wt% of at least one intermediate oxide from the oxides of the
group of Al203 and MgO, as well as /
• 0 wt% to 50 wt% of one or afore opacifying agents from the oxides of the
group of Ti02, Sn02 and Zr02,is well as Ca3(P04)2 and Na3AlF6.
[0052J Alternatively or in/addition, the mean grain size may, for example, be less
than 5 u.m and, for example, less than 1 urn, when using the frit containing ZnO.
(0053] Alternatively or in addition, the degree of whiteness measured against air as
environmental nwlium, expressed by the L value in the CieL*a*b measuring system,
may be greater than 90 points, when using the frit containing ZnO.
[0054] / Alternatively or in addition, the frit containing ZnO may be prepared by
melting customary oxides, silicates, borates, carbonates or fluorides at 600 °C to 1,400
5C, by cooling and, as the case may be, by tempering again and by grinding, when using
the frit containing ZnO.
17
[0055] Alternatively or in addition, the ZnO may exist in a crystalline form and/or a#
a component part of the network of the glass phase in the frit, when using the frit /
containing ZnO. /
[0056] Alternatively or in addition, the crystalline ZnO of the frit may foave a mean
crystallite size of less than 300 nm and, for example, of less than 100 m\, when using the
frit containing ZnO. /
[0057] Alternatively or in addition, when using the frit coHiaining ZnO, the
application concentration of the frit containing ZnO may m greater than 0.01 wt% and
less than 90 wt%, for example between 0.1 wt% and I'D wt%, and, for example, between
0.2 wt% and 6 wt%, in the inventive areas of application.
[0058] Alternatively or in addition, whenoising the frit containing ZnO, the frit
containing ZnO may be used as a UV pr/ftection pigment in dark colored synthetic
materials or lacquers/varnishes with/an L value in the CieL*a*b measuring system of less
than 85 points. /
[0059] Alternatively orjn addition, the thermoplastically deformable synthetic
materials may be PVC^PMMA, ASA, WPC, PP, PE, PS, EVA, PIB, PC and ABS, the
thermosetting syndetic materials may be aminoplasts, phenolic plastics, polyurethanes,
epoxy resins anra polyacrylates, the solvent-containing lacquers/varnishes may be alkyd
resin lacquers/varnishes, polyester paints, epoxy resin lacquers/varnishes and
polyupethane resin lacquers/varnishes, the paints and lacquers/varnishes may be
compounds based on acrylic polymers and polystyrene and polyvinyl resin lacquers/
varnishes, the water-based lacquers/varnishes may be dispersion paints, dispersion
18
lacquer/varnish paints, groundings and coating agents^artd the hydraulic-setting
construction products may be joint compGuntTs, cements and plasters.
19
Claims
What is claimed is:
1. Use of a zinc-oxide containing frit with a ZnO content of 20 wt% to 75 wt% ayfa
an average grain size of less than 30 jam as a UV light absorbing UV protection m£ans in
a carrier material, for example in a thermoplastically deformable synthetic material, a
thermosetting synthetic material, a solvent-containing lacquer/varnish, a wafer-based
lacquer/varnish, a radiation-curing lacquer/varnish or lacquer/varnish system, a powder
lacquer/varnish or powder lacquer/vamish system, another carrier mmerial based on a
synthetic or natural polymer or wax, a paper coating or a hydraulic-setting construction
product. /
2. Use of a frit containing ZnO according to claim 1, characterized in that the frit
containing ZnO is, in addition to 20 wt% to 75 w*% of ZnO, further composed of:
• 5 wt% to 80 wt% of at least one network former from the oxides of the group
of Si02, B203 and P205, /
• 0.05 wt% to 50 wt% of ax least one network modifier from the oxides of the
group of BaO, CaO, Sr& K20, Na20 and Li20,
• 0 wt% to 50 w$>, for example 5 wt% to 50 wt%, of at least one intermediate
oxide from uWoxides of the group of AI2O3, V2O5, Fe203 and MgO, as well as
• 0 wt^/to 50 wt% of one or more opacifying agents from the oxides of the
grou/of Ti02, Sn02 and Zr02, Ce02 as well as Ca3(P04)2 and Na3AlF6.
3. / Use of a frit containing ZnO according to any of claims 1 to 2, characterized in
/Cnat the average grain size is less than 5 um, for example less than 1 um.
20
4. Use of a frit containing ZnO according to any of claims 1 to 3, characterized in
that the degree of whiteness of the frit measured against air as environmental medium,
expressed by the L value in the CieL*a*b measuring system, is greater than 9Q/points.
5. Use of a frit containing ZnO according to any of claims 1 to 4, izfnaracterized in
that the frit containing ZnO is prepared by melting commercially available oxides,
silicates, borates, carbonates or fluorides, such as zinc oxide, feldspars, quartz powder,
soda, zirconium silicate, rutile, calcspar, barium carbonate, cn^olite etc., at 600 °C to
1,400 °C, by cooling, by optionally tempering again, and by grinding.
6. Use of a frit containing ZnO according to awy of claims 1 to 5, characterized in
that the ZnO is provided in a crystalline form ana/or as a component part of the network
of the glass phase in the frit. /
7. Use of a frit containing ZnO according to claim 6, characterized in that the
crystalline ZnO of the frit has an a/erage crystalHte size of less than 300 nm, for example
of less than 100 nm. /
8. Use of a frit containing ZnO according to any of claims 1 to 7, characterized in
that the application concentration of the frit containing ZnO in the carrier material is
greater than 0.01 wt% and less than 90 wt%, for example between 0.1 wt% and 10 wt%,
for example between 0.2 wt% and 6 wt%.
9. /Jse of a frit containing ZnO according to any of claims 1 to 8, characterized in
thaUrie frit containing ZnO is used as a UV protection means in a dark colored synthetic
material or lacquer/varnish with an L value in the CieL*a*b measuring system of less
than 85 points.
21
10. Use of a frit containing ZnO according to any of claims 1 to 9, characterized irr
that the thermoplastically deformable synthetic material is PVC, PMMA, ASA, WFC,
PP, PE, PS, EVA, PIB, PC or ABS, the thermosetting synthetic material is an atfiinoplast,
phenolic plastic, polyurethane, epoxy resin or polyacrylate, the solvent-containing
lacquer/varnish is alkyd resin lacquer/varnish, polyester paint, epoxy resin lacquer/
varnish, polyurethane resin lacquer/varnish or a paint or a lacquer/varmsh based on
acrylic polymers, polystyrene and polyvinyl resin lacquers/varnishes, the water-based
lacquer/varnish is a dispersion paint, dispersion lacquer/varnish/paint, grounding or
coating agent, and the hydraulic-setting construction produces ajoint compound, cement
or plaster. /
11. Use of a frit containing ZnO according to/any of claims 1 to 10, characterized in
that the ZnO concentration in the frit is greate/than 30 wt%, for example greater than
50 wt%. /
12. PVC synthetic material, into which a zinc-oxide containing frit with a ZnO
content of 20 wt% to 75 wt% aoo an average grain size of less than 30 um is incorporated
as a UV light absorbing UV^protection means.
13. PVC synthetic material according to claim 12, wherein the concentration of the
frit containing ZnO is greater than 0.01 wt% and less than 90 wt%, for example between
0.1 wt% and W wt%, for example between 0.2 wt% and 6 wt%.
14. /PVC synthetic material according to claim 12 or 13, wherein the average grain
siz/of the frit containing ZnO is less than 5 um, for example less than 1 um.
22
15. PVC synthetic material according to any of claims 12 to 14, wherein the degree ot
whiteness of the frit, measured against air as environmental medium, expressed by the L
value in the CieL*a*b measuring system, is greater than 90 points. /
16. PVC synthetic material according to any of claims 12 to 15/wherein the PVC
synthetic material has an L value in the CieL*a*b measuring system of less than 85
points. /
17. PVC synthetic material according to apy of claims 12 to 16, wherein the ZnO is
provided in a crystalline form and/or as a>eomponent part of the network of the glass
phase in the frit. /
18. PVC synthetic material according to claim 17, wherein the crystalline ZnO of the
frit has an average crystallite size of less than 300 nm, for example of less than 100 nm.
19. PyC synthetic material according to any of claims 12 to 18, wherein the ZnO
concentration in the frit is greater than 30 wt%, for example greater than 50 wt%.