U.S. patent application number 13/538861 was filed with the patent office on 2012-12-27 for carbon black, method of producing carbon black and device for implementing the method.
This patent application is currently assigned to Evonik Carbon Black GmbH. Invention is credited to Alfons Karl, Matthias Katzer, Kai Krauss, Catharina Quitmann, Michael Stanyschofsky.
Application Number | 20120328881 13/538861 |
Document ID | / |
Family ID | 38828702 |
Filed Date | 2012-12-27 |
United States Patent
Application |
20120328881 |
Kind Code |
A1 |
Quitmann; Catharina ; et
al. |
December 27, 2012 |
Carbon Black, Method of Producing Carbon Black and Device for
Implementing the Method
Abstract
The invention relates to a carbon black having an aggregate size
distribution which has a (d.sub.90-d.sub.10)/d.sub.50 ratio of less
than or equal to 1.1. The carbon blacks are produced by admixing
hot air if desired to a gas mixture comprising a carrier gas and a
carbon black feedstock, passing the gas mixture into a burner pipe,
burning the gas mixture at the burner pipe openings, and drawing
the flames under suction, together with the ambient air drawn in
freely under suction from the outside, through a cooled, narrowing
gap, and carrying out cooling, the cooled, narrowing gap having a
height (h) to width (b) ratio of 1-100, the width (b) being 0.5 to
10 mm, and the flow rate at the narrowest point of the gap being
10-200 m/s. The carbon blacks can be used as non-reinforcing
filler, reinforcing filler, UV stabilizer, conductive black,
pigment or reducing agent.
Inventors: |
Quitmann; Catharina; (Koln,
DE) ; Karl; Alfons; (Grundau, DE) ; Katzer;
Matthias; (Schluchtern, DE) ; Krauss; Kai;
(Grosskrotzenburg, DE) ; Stanyschofsky; Michael;
(Hurth, DE) |
Assignee: |
Evonik Carbon Black GmbH
Hanau
DE
|
Family ID: |
38828702 |
Appl. No.: |
13/538861 |
Filed: |
June 29, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11882702 |
Aug 3, 2007 |
8236274 |
|
|
13538861 |
|
|
|
|
Current U.S.
Class: |
428/402 |
Current CPC
Class: |
C09C 1/52 20130101; C08K
3/04 20130101; C08K 3/04 20130101; C01P 2006/66 20130101; C01P
2006/12 20130101; C01P 2004/50 20130101; Y10T 428/2982 20150115;
C08L 21/00 20130101; C01P 2004/51 20130101 |
Class at
Publication: |
428/402 |
International
Class: |
C01B 31/00 20060101
C01B031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 7, 2006 |
DE |
10 2006 037 079.1 |
Claims
1. Carbon black comprising an aggregate size distribution with a
(d.sub.90-d.sub.10)/d.sub.50 ratio of less than or equal to 1.1 and
a full width at half-maximum (FWHM) to D.sub.mode ratio of less
than or equal to 0.6 and wherein said carbon black is a gas
black.
2. The carbon black of claim 1, wherein said aggregate size
distribution has a full width at half-maximum (FWHM) to D.sub.mode
ratio of 0.54-0.60.
3. The carbon black of claim 2, wherein said carbon black has a
surface oxide content greater than 50 mmol/kg.
4. The carbon black of claim 2, wherein said carbon black has a
surface oxide content greater than 120 mmol/kg.
5. A composition comprising carbon blacks according to claim 1,
wherein said composition is selected from the group consisting of:
a non-reinforcing filler, a reinforcing filler, a UV stabilizer, a
conductive black, a pigment, a reducing agent, rubber, plastic,
printing inks, liquid inks, inkjet inks, toners, coating materials,
paints, paper, bitumen, concrete and other building materials.
6. The composition of claim 5, selected from the group consisting
of: a non-reinforcing filler, a reinforcing filler, a UV
stabilizer, a conductive black, a pigment, and a reducing
agent.
7. The composition of claim 6, wherein said carbon blacks have an
aggregate size distribution with a full width at half-maximum
(FWHM) to D.sub.mode ratio of 0.54-0.60.
8. The composition of claim 6, wherein said carbon black has a
surface oxide content greater than 50 mmol/kg.
9. The composition of claim 7, wherein said carbon black has a
surface oxide content greater than 50 mmol/kg.
10. The composition of claim 5, selected from the group consisting
of: rubber, plastic, printing inks, liquid inks, inkjet inks,
toners, coating materials, paints, paper, bitumen, concrete and
other building materials.
11. The composition of claim 10, wherein said carbon blacks have an
aggregate size distribution with a full width at half-maximum
(FWHM) to D.sub.mode ratio of 0.54-0.60.
12. The composition of claim 10, wherein said carbon black has a
surface oxide content greater than 50 mmol/kg.
13. The composition of claim 12, wherein said carbon black has a
surface oxide content greater than 50 mmol/kg.
14. The composition of claim 5, selected from the group consisting
of: printing inks, liquid inks, inkjet inks, toners.
15. The composition of claim 14, wherein said carbon blacks have an
aggregate size distribution with a full width at half-maximum
(FWHM) to D.sub.mode ratio of 0.54-0.60.
16. The carbon black of claim 1, wherein said carbon black
comprises an aggregate size distribution with a
(d.sub.90-d.sub.10)/d.sub.50 ratio 0.57-0.60.
17. The carbon black of claim 16, wherein said carbon black has a
volatiles content of 4.0-9.0%.
18. The carbon black of claim 16, wherein said carbon black has a
surface oxide content greater than 120 mmol/kg.
19. The composition of claim 10, wherein said carbon blacks
comprise an aggregate size distribution with a
(d.sub.90-d.sub.10)/d.sub.50 ratio 0.57-0.60.
20. The composition of claim 19, wherein said carbon blacks have a
volatiles content of 4.0-9.0% and a surface oxide content greater
than 120 mmol/kg.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. Ser. No.
11/882,702, filed on Aug. 3, 2007, which claims priority to German
application 10 2006 037 079.1, filed on Aug. 7, 2006. These prior
applications are hereby incorporated by reference in their
entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a carbon black, to a method of
producing carbon black, and to a device for implementing the
method.
BACKGROUND OF THE INVENTION
[0003] DE 2404536 discloses a method of producing gas blacks having
a low extractables content, wherein hydrogen-rich mixtures are used
as carrier gas for the carbon black oil vapour, and the carbon
black deposited on the cooling roll is collected. These gas blacks
have an extractables content of less than 0.100% by weight.
[0004] Furthermore, WO 2005/033217 discloses unscreened, untreated
carbon blacks, having a pH of less than or equal to 6.0, a residue
on ignition of less than or equal to 0.1%, and a 5 .mu.m sieve
residue of less than or equal to 200 ppm. These blacks are produced
by the method steps of removing the heat from the flame by thermal
conduction and/or radiation, forming a thin gas boundary layer, and
accelerating or expanding the flow formed by the flame and the
boundary layer.
[0005] A disadvantage of the known blacks is the poor hue
contribution in coatings applications.
OBJECT OF THE INVENTION
[0006] It is an object of the invention to provide a carbon black
which features a high positive hue contribution in coatings
applications. It is a further object of the invention to provide a
method which removes as much heat as possible from the flame,
without allowing the resulting black to accumulate on the cold
surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows the diagrammatic construction of an apparatus,
for making carbon blacks.
DESCRIPTION OF THE INVENTION
[0008] The invention provides a carbon black which is characterized
in that the aggregate size distribution has a
(d.sub.90-d.sub.10)/d.sub.50 ratio of less than or equal to 1.1,
preferably less than 0.8, more preferably less than 0.65.
[0009] The carbon black of the invention may have a surface oxide
content of greater than 50 mmol/kg, preferably greater than 100
mmol/kg, more preferably greater than 120 mmol/kg.
[0010] The carbon black of the invention may have an aggregate size
distribution with a full width at half-maximum (FWHM) to D.sub.mode
ratio of less than or equal to 0.6, preferably less than 0.58, more
preferably less than 0.56.
[0011] The carbon black of the invention may be a gas black.
[0012] The pH of the carbon blacks of the invention may be <7.0,
preferably <6.0, more preferably <5.0.
[0013] The carbon black of the invention can have an STSA value of
20-300 m.sup.2/g, preferably of 50-220 m.sup.2/g, more preferably
of 70-200 m.sup.2/g.
[0014] The carbon black of the invention may have a volatiles
content of 2.0-20.0%, preferably of 3.0-12%, more preferably of
4.0-9.0%.
[0015] The carbon black of the invention may have a tint of
90-180%, preferably of 105-106%, more preferably of 120-150%.
[0016] The invention further provides a method of producing carbon
black of the invention, which is characterized in that a gas
mixture comprising a carrier gas and a carbon black feedstock is if
desired admixed with hot air, the gas mixture is passed into a
burner pipe, the gas mixture burns at the burner pipe openings, and
the flames, together with the ambient air drawn in freely under
suction from outside, are sucked through a cooled, narrowing gap
and cooled, the cooled, narrowing gap having a height (h) to width
(b) ratio of 1-100, preferably 5-50, more preferably 10-40, the
width being based on the top edge of the gap, the width (b) being
0.5 to 10 mm, preferably 1 to 5 mm, and the flow rate at the
narrowest point of the gap being 10-200 m/s, preferably 15-150 m/s,
more preferably 20-100 m/s.
[0017] The flow rate can be calculated from the ratio of
operational gas volume to gap area. The operational gas volume is
the volume of gas taken off under suction via the fan. The gap area
is given by the product of gap width b and top edge A.sup.1A.sup.2
of the cooled, narrowing gap.
[0018] The coolant used for the narrowing gap may be water, air,
steam and heat-transfer oil.
[0019] In a commercially customary thin-film evaporator the carbon
black feedstock can be heated and vaporized. The carbon black
feedstock vapour is supplied by a stream of carrier gas to a burner
pipe. Immediately upstream of the burner pipe (described for
example in DE-C 671739) the gas mixture can be admixed with hot air
at temperatures of up to 400.degree. C., and supplied to the
flames. The carbon black produced can be separated in commercially
customary filter systems.
[0020] The carbon black feedstock used may comprise carbonaceous
gases or vaporizable carbonaceous liquids. Carbon black feedstock
used may comprise hydrocarbons, such as acetylene, methane,
ethylene, ethane, propane, butane or pentane, or carbon black oil.
Carbon black oil may be of petrochemical or carbochemical origin.
The carbon black feedstock used may be a mixture of hydrocarbons
and/or carbon black oils.
[0021] The gaseous or vaporized carbon black feedstock may have a
temperature of up to 400.degree. C., preferably 250-400.degree. C.,
more preferably 250-350.degree. C.
[0022] As carrier gas it is possible to use combustible gases,
preferably gas mixtures having a hydrogen fraction >50% by
volume, more preferably >60% by volume.
[0023] The carrier gas temperature and hot air temperature may
correspond at least to the temperature of the gaseous or vaporized
carbon black feedstock, in order to prevent condensation.
[0024] FIG. 1 shows the diagrammatic construction of the apparatus,
where the reference symbols have the following meanings: [0025]
A.sup.1A.sup.2, A.sup.1',A.sup.2': top edge of the cooled,
narrowing gap, [0026] B.sup.1,B.sup.2, B.sup.1',B.sup.2': bottom
edge of the cooled, narrowing gap, [0027] A.sup.1',A.sup.1,
A.sup.2',A.sup.2: narrowest point of the cooled, narrowing gap,
[0028] b: width of the cooling gap=A.sup.1',A.sup.1 or
A.sup.2',A.sup.2 [0029] B.sup.1',B.sup.1, B.sup.2',B.sup.2: widest
point of the cooled, narrowing gap, [0030] h: height of the cooled,
narrowing gap in the upper region, [0031] h': height of the
uncooled or cooled, obliquely converging sidewalls, [0032]
C.sup.1B.sup.1B.sup.2C.sup.2: uncooled or cooled, obliquely
converging sidewall, [0033] C.sup.1'B.sup.1'B.sup.2+C.sup.2':
uncooled or cooled, obliquely converging sidewall, [0034]
D.sup.1',D.sup.1: width of the vertically placed apparatus, [0035]
E: height-adjustable burner pipe. [0036] E, A.sup.1A.sup.1': Burner
spacing
[0037] The angle .alpha. can be 70.degree. to 89.degree.,
preferably 80.degree. to 89.degree., more preferably 83.degree. to
88.degree..
[0038] The height h' can be 0 to 250 mm, preferably 100 to 250 mm,
more preferably 140 to 180 mm.
[0039] The width of the vertically placed apparatus
(C.sup.1'C.sup.1=D.sup.1'D.sup.1) can amount to 100 to 500 mm,
preferably 150 to 210 mm.
[0040] The exhaust hood may follow the gap directly and may be
connected to a suction withdrawal fan.
[0041] The apparatus may be manufactured of stainless steel in
order to prevent the typical impurity (grit). In the case of the
method of the invention there is no need for a rotating cooling
roll. The flames of the burner pipe can be sucked through and
cooled by a water-cooled, narrowing gap.
[0042] As shown in the sectional drawing of the apparatus of the
invention (FIG. 1), the gap may extend over the entire length of
the apparatus and may run parallel to the burner pipe, i.e. it can
be disposed, preferably with centring, above the burner pipe. The
sidewalls of the vertically placed apparatus may initially run
parallel to one another (C.sup.1D.sup.1D.sup.2C.sup.2 or
C.sup.1'D.sup.1'D.sup.2'C.sup.2'), then converge obliquely on one
another (C.sup.1B.sup.1B.sup.2C.sup.2 or
C.sup.1'B.sup.1'B.sup.2'C.sup.2'), and end in the cooled, narrowing
gap (A.sup.1B.sup.1B.sup.2A.sup.2 or
A.sup.1'B.sup.1'B.sup.2'A.sup.2').
[0043] The burner spacing with respect to the cooled, narrowing gap
can be made variable. This adjustment facility can be provided in
order to allow the realization of an optimum burner height.
[0044] In the conically converging region (h') of the apparatus it
is possible for the sidewalls to be water-cooled. In the region
(h'), however, this may only serve to protect the material from the
flame temperature, since it is only in the upper region (h), the
correspondingly named cooling gap, that the cooling of the reaction
mixture is to take place.
[0045] The construction of the cooling gap may be designed such
that, as a result of the generation of a laminar boundary layer at
the cooling gap, the accumulation of carbon black can be
prevented.
[0046] Additives can be added to the carbon black oil. Additives
may be a solution of salt in water, alcohol, oil or mixtures
thereof. The additives can be converted into an aerosol. The salt
used can with preference be potassium carbonate.
[0047] The invention further provides a device for implementing the
process of the invention, having a burner and a cooling surface
against which the flame is directed, which is characterized in that
the cooled, narrowing gap has a height (h) to width (b) ratio of
1-100, preferably 5-50, more preferably 10-40, the width being
based on the top edge of the gap, the width (b) is 0.5 to 10 mm,
preferably 1 to 5 mm and the flow rate at the narrowest point of
the gap is 10-200 m/s, preferably 15-150 m/s, more preferably
20-100 m/s.
[0048] The carbon blacks of the invention can be used as
non-reinforcing filler, reinforcing filler, UV stabilizer,
conductive black or pigment. The carbon blacks of the invention can
be used in rubber, plastic, printing inks, liquid inks, inkjet
inks, toners, coating materials, paints, paper, bitumen, concrete
and other building materials. The carbon blacks of the invention
can be employed as a reducing agent in metallurgy.
[0049] The carbon blacks of the invention have the advantage that
blacks with a narrow aggregate size distribution can be produced,
and the absolute hue contribution (dM) in coatings applications is
very high.
[0050] The method of the invention has the advantage that the black
does not deposit on the cooled surfaces and can therefore be
deposited outside of the device.
[0051] A further advantage is that in the apparatus of the
invention there are no longer any rotating parts, which reduces the
capital costs and maintenance costs, and that there is no longer
separation between roll black and filter black, and hence the
product produced is homogenized. As a result of the removal of
mechanical conveying, moreover, it is possible to lower the level
of impurities in the product.
EXAMPLES
[0052] The apparatus of the invention used in the examples in
accordance with FIG. 1 has a sidewall distance (D.sup.1'D.sup.1) of
177 mm and a height (D.sup.1C.sup.1) of 600 mm. Above a height of
600 mm, the sidewalls converge obliquely on one another and end in
the cooled, narrowing gap. In the examples which follow, the length
A.sup.1A.sup.2 of this cooling gap amounts to 2000 mm and the
height (h) amounts to 50 mm. The height (h') of the gap in the
examples below amounts to 159 mm. The angle .alpha. is
87.degree..
Methods
[0053] pH
[0054] The pH is determined in accordance with DIN EN ISO 787-9
20.
Volatiles
[0055] The volatiles are determined at 950.degree. C. in accordance
with DIN 53552.
BET Surface Area
[0056] The BET surface area is determined in accordance with ASTM
D-6556-00.
STSA Surface Area
[0057] The STSA surface area is determined in accordance with ASTM
specification D-6556-00.
Tint
[0058] The tint strength is determined in accordance with ASTM
specification D-3265.
Aggregate Size Distribution
[0059] The aggregate size distribution curves are measured using a
Brookhaven BI-DCP disc centrifuge with red-light diode. This
instrument is a development specifically for determining aggregate
size distribution curves of finely divided solids from absorbance
measurements, and is equipped with an automatic measuring and
evaluation program for determining the aggregate size
distribution.
[0060] To carry out the measurements, first of all a dispersion
solution is prepared from 200 ml of ethanol, 5 drops of ammonia
solution and 0.5 g of Triton X-100, made up to 1000 ml with
demineralized water. Additionally a spin fluid is prepared from 0.5
g of Triton X-100 and 5 drops of ammonia solution, made up to 1000
ml with demineralized water.
[0061] Subsequently 20 ml of dispersion solution are added to 20 mg
of carbon black, which are suspended in the solution for a period
of 4.5 minutes in a cooling bath with 100 watts of ultrasound (80%
pulse).
[0062] Prior to the beginning of the actual measurements, the
centrifuge is operated for 30 minutes at a speed of 11 000
min.sup.-1. With the disc spinning, 1 ml of ethanol is injected,
and then a bottom layer of 15 ml of spin fluid is carefully laid
down. After about a minute, 250 .mu.l of the black suspension are
injected, the instrument's measuring program is started, and the
spin fluid in the centrifuge is overlaid with 50 .mu.l of dodecane.
A duplicate determination is performed on each sample for
measurement.
[0063] The raw data curve is then evaluated using the instrument's
arithmetic program, with correction for scattered light and with
automatic baseline adaptation.
[0064] The .DELTA.D.sub.50 value (FWHM) is the width of the
aggregate size distribution curve at half the peak height. The
D.sub.mode value (modal value) is the aggregate size having the
greatest frequency (peak maximum of the aggregate size distribution
curve). The values d.sub.10, d.sub.50 and d.sub.90 are the
aggregate sizes determined from the cumulative curve with a volume
fraction of 10%, 50% and 90%, respectively.
Surface Oxides
[0065] Regarding the characterization and quantification of surface
oxides on the carbon black's surface, i.e., here, functional groups
containing oxygen, such as carboxyl, lactol and phenol groups:
[0066] The initial mass of carbon black, m.sub.i, is guided by the
number of surface oxides anticipated. As a starting point for the
initial mass, the volatiles content of the carbon black can be
employed (Table 1).
TABLE-US-00001 TABLE 1 Volatiles content Initial mass Volatiles
Initial mass in % of carbon content in % of carbon by weight black,
m.sub.i in g by weight black, m.sub.i in g 1 5 16-17 1 2 4.5 18-19
0.9 3-6 4 20-23 0.8 7-9 3 24 0.7 10-11 2 25 0.6 12-15 1.5 26
0.5
[0067] The quantity of carbon black specified in Table 1, dried at
105.degree. C., is weighed out to an accuracy of 0.1 mg into a
glass centrifuge tube, and 25 ml (volume V.sub.1) of 0.05 M aqueous
sodium hydroxide solution are added. The air in the centrifuge tube
above the sample is displaced by nitrogen, and the tube is tightly
sealed, inserted into a holder, and mixed overnight in a rotation
machine.
[0068] After the end of the mixing procedure, the contents are
transferred to another centrifuge tube and centrifuged for at least
1 minute.
[0069] 10 ml (volume V.sub.2) of the supernatant solution are
withdrawn by pipette and transferred to a glass beaker, 20 ml of
0.025 m sulphuric acid are added, and the mixture is boiled briefly
in order to expel carbonate.
[0070] The samples are subsequently back-titrated with 0.05 m
aqueous sodium hydroxide solution to a pH of 6.5 (pH electrode).
The amount of sodium hydroxide solution consumed is V.sub.3.
[0071] A blank sample must be prepared accordingly. To determine
the blank value, the amount of NaOH consumed, Bl.sub.3, is obtained
similarly.
[0072] On the basis of the initial carbon black mass m.sub.i, the
volumes V.sub.1-3 and Bl.sub.3, the amount of surface oxides, G, in
mmol/kg, is calculated in accordance with the following
equation:
G = V 1 ( V 3 - Bl 3 ) V 2 m i 0 , 05 [ mol l ] 1000
##EQU00001##
[0073] In this formula the symbols have the following meanings:
[0074] m.sub.i: Initial carbon black mass in g, [0075] V.sub.1:
Volume in ml of the reagent solutions (=25 ml) added to the carbon
black, [0076] V.sub.2: Volume in ml of sample solution withdrawn by
pipette (=10 ml), [0077] V.sub.3: Amount of sodium hydroxide
solution consumed for titration, in ml, [0078] Bl.sub.3: Amount of
sodium hydroxide consumed, in ml, for the blank value
titration.
Relative Black Value My and Absolute Hue Contribution dM
Description/Procedure
1. Preparation of Reagents
Diluent Formula
TABLE-US-00002 [0079] Ingredients in g in % by wt. Xylene 1125
68.20 Ethoxypropanol 225 13.63 Butanol 150 9.09 Baysilon OL 17, 10%
in xylene 75 4.54 Butyl glycol 75 4.54 Total 1650 100
Baysilon Formula
TABLE-US-00003 [0080] Ingredients in g in % by wt. Baysilon OL 17
10 10 Xylene 90 90 Total 100 100
Component A
TABLE-US-00004 [0081] Ingredient in g in % by wt. Alkydal F 310,
60% 770 77 Diluent 230 23 Total 1000 100
Component B
TABLE-US-00005 [0082] Ingredient in g in % by wt. Maprenal MF800,
55% 770 77 Diluent 230 23 Total 1000 100
[0083] The ingredients of the 4 formulas are mixed and are kept in
a suitable vessel.
2. Preparation of the Black Coating
[0084] Formula of the black coating for determining the black value
My:
TABLE-US-00006 Ingredient in g in % by wt. Standard clearcoat
component A 27.3 65.3 Standard clearcoat component B 12.7 30.4
Carbon black pigment 1.8 4.3 Total 41.8 100
[0085] First of all the coating components A and B are weighed out
into a PTFE beaker, then the carbon black pigment, dried at
105.degree. C., is weighed in, and 275 g of steel beads (O=3 mm)
are added as grinding media. Finally the sample is dispersed in a
Skandex mixer for 30 minutes.
[0086] After the dispersing procedure, approximately 1-2 ml of
black coating are taken for the drawdown and applied to the support
plate in a stripe 5 cm long and approximately 1 cm in width. Care
should be taken to ensure that there are no air bubbles in the
coating stripe. The film drawing bar is placed over the stripe of
coating and drawn uniformly across the plate. A drawdown is
produced which is approximately 10 cm long and 6 cm wide. The
drawdown must be air-dried (in a fume cupboard) for at least 10
minutes.
[0087] Subsequently the sample is baked at 130.degree. C. in a
drier for 30 minutes. The samples can be subjected to measurement
immediately after cooling or later. The measurements can be carried
out using the Pausch Q-Color 35 instrument with WinQC+ software.
The measurement takes place through the glass.
3. Calculations
3.1. Formulae and Constants
3.1.1 Hue-Independent Black Value My and Hue-Dependent Black Value
Mc
[0088] First of all the hue-independent black value My is
calculated (Equation 1) from the tristimulus value Y of the
measurement (illuminant D65/10):
My = 100 log ( 100 Y ) ( 1 ) ##EQU00002##
[0089] Subsequently the hue-dependent black value (Equation 2) is
calculated:
Mc = 100 ( log ( X n X ) - log ( Z n Z ) + log ( Y n Y ) ) ( 2 )
##EQU00003##
[0090] X.sub.n/Z.sub.n/Y.sub.n (DIN 6174)=tristimulus values of the
coordinate origin, based on the illuminant and the observer (DIN
5033/part 7, illuminant D65/10.degree.)
[0091] X.sub.n=94.81 Zn=107.34 Y.sub.n=100.0
[0092] X/Y/Z=tristimulus values calculated from the measurements of
the samples.
3.1.2 Absolute Hue Contribution dM
[0093] The absolute hue contribution dM (Equation 3) is calculated
from the black values Mc and My:
dM=Mc-My (3)
Examples 1-10
[0094] The settings for the production of the examples for the
inventive carbon blacks, and of Comparative Example 6, are listed
in Table 2. A device as per FIG. 1 is used.
[0095] For the inventive examples and for Comparative Example 6 the
hot air temperature is 310.degree. C. and the hydrogen content of
the carrier gas is 92-99% by volume.
[0096] The burner spacing reported in Table 2 is the distance from
the top edge of the burner pipe, in other words the point at which
the oil vapour-carrier gas mixture emerges, to the top edge of the
cooled, narrowing cooling gap.
[0097] In the subsequent table, Table 3, the analytical data of the
inventive carbon blacks and of a comparison black are shown. The
comparison black used (Example 7) is that of Example 3 from WO
2005/033217.
TABLE-US-00007 TABLE 2 Gap dimensions Gap Burner Carrier gas Oil
vapour Operational Flow height: width b spacing Hot air volume
quantity gas volume rate Example width mm [mm] [m.sup.3/h(stp)]
[m.sup.3/h(stp)] [m.sup.3/h(stp)] [m.sup.3/h(stp)] [m/s] 1 12.5 4
171 9 3 3 650 22.6 2 25 2 181 14 4 3.2 650 45.1 3 25 2 171 14 3 3.2
650 45.1 4 25 2 181 18 4 3.2 650 45.1 5 33 1.5 181 17 4 3.2 650
60.2 6 12.5 4 171 9 4 3 250 8.7 (Comparative Example)
TABLE-US-00008 TABLE 3 Volatiles BET STSA (950.degree. C.) Tint
Surface oxides Coating Coating (d.sub.90-d.sub.10)/ FWHM/ Example
[m.sup.2/g] [m.sup.2/g] [%] pH [%] [mmol/kg] My dM d.sub.50
D.sub.mode 1 93.1 76.1 4.8 3 120.5 130 251 4.2 0.57 0.55 2 142.9
118.7 4.3 3.6 141.3 170 284 15 0.58 0.55 3 169.5 132.2 4.5 3.4
142.6 200 293 18.5 0.60 0.54 4 274 190.9 8.76 3.07 146.6 320 282
2.3 0.64 0.60 5 274.8 192.3 7.75 3.1 141.3 290 284 4.4 0.64 0.58 6
(Comparative Example) Experiment discontinued owing to deposition
of black in the cooled, narrowing gap 7 (Comparative Example) 316.6
244.2 4.62 3.9 220 291 -0.8 1.35 0.63
[0098] The results show that the carbon blacks of the invention
(Examples 1-5) have an aggregate size distribution with a
(d.sub.90-d.sub.10)/d.sub.50 ratio of less than or equal to 1.1.
The advantage of the carbon blacks of the invention is manifested
in a dM value of >0.5 and in a resulting higher blue hue.
[0099] All references cited herein are fully incorporated by
reference. Having now fully described the invention, it will be
understood by those of skill in the art that the invention may be
practiced within a wide and equivalent range of conditions,
parameters and the like, without affecting the spirit or scope of
the invention or any embodiment thereof.
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