Patent EP0848286A1 successfully refreshed from Google Patents.
EP0848286A1
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EP
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Thermographic recording material with improved image tone and/or stability upon thermal development
Assignee: Agfa Gevaert NV
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Filing: 1997-12-06
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Granted: —
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Expires: 2017-12-06
Abstract
Abstract A recording material comprising a support and a thermosensitive element comprising silver behenate, an organic reducing agent therefor in thermal working relationship therewith and a binder, characterized in that the silver behenate is not associated with mercury and/or lead ions and when the recording material is irradiated with a copper Kα 1 X-ray source the ratio, normalized to a quantity of silver in the recording material of 1g per m 2 thereof, of the sum of the peak heights of the X-ray diffraction lines attributable to silver behenate at Bragg angles, 2Θ, of 6.01°, 7.56°, 9.12°, 10.66°, 12.12° and 13.62° to the sum of the peak heights of the X-ray diffraction lines at Bragg angles, 2Θ, of 25.60°, 35.16° and 43.40° of NIST standard 1976, rhombohedral Al 2 O 3 , determined with the same X-ray diffractometer in the same state of adjustment, is greater than 0.85; production processes for particles of substantially light-insensitive organic silver salt comprising silver behenate with these X-ray characteristics in the presence and substantial absence of organic solvent.
Inventors
- 👤 Sabine Emmers
- 👤 Bartholomeus Horsten
- 👤 Ingrid Geuens
- 👤 Yvan Gilliams
- 👤 André Bellens
- 👤 Dirk Bollen
- 👤 Ivan Hoogmartens
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 09:45
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/494; G03C1/498; G03C1/49809; C; C07; C07C; C07C51/00; C07C51/41; C07C51/412; G03C1/4989; G03C1/005; G03C1/015; G03C2001/0157; G03C1/76; G03C1/7614; G03C2001/7635; G03C2200/00; G03C2200/43
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
147 words
A recording material comprising a support and a thermosensitive
element comprising silver behenate, an organic reducing agent
therefor in thermal working relationship therewith and a binder,
characterized in that said silver behenate is not associated
with mercury and/or lead ions and when said recording material
is irradiated with a copper Kα 1 X-ray source the ratio,
normalized to a quantity of silver in said recording material of
1g per m 2 thereof, of the sum of the peak heights of the X-ray
diffraction lines attributable to silver behenate at Bragg
angles, 2Θ, of 6.01°, 7.56°, 9.12°, 10.66°, 12.12° and 13.62° to
the sum of the peak heights of the X-ray diffraction lines at
Bragg angles, 2Θ, of 25.60°, 35.16° and 43.40° of NIST standard
1976, rhombohedral Al 2 O 3 , determined with the same X-ray
diffractometer in the same state of adjustment, is greater than
0.85.
Claim 2
Dependent Claim
28 words
Recording material according to claim 1, wherein said silver
behenate is present in said thermosensitive element as particles
of substantially light-insensitive organic silver salt
comprising said silver behenate.
Claim 3
Dependent Claim
102 words
Recording material according to claim 1 or 2, wherein said
ratio, normalized to a quantity of silver in said recording
material of 1g per m 2 thereof, of the sum of the peak heights of
the X-ray diffraction lines attributable to silver behenate at
Bragg angles, 2Θ, of 6.01°, 7.56°, 9.12°, 10.66°, 12.12° and
13.62° to the sum of the peak heights of the X-ray diffraction
lines at Bragg angles, 2Θ, of 25.60°, 35.16° and 43.40° of NIST
standard 1976, rhombohedral Al 2 O 3 , determined with the same X-ray
diffractometer in the same state of adjustment, is greater
than 1.0.
Claim 4
Dependent Claim
102 words
Recording material according to claim 1 or 2, wherein said
ratio, normalized to a quantity of silver in said recording
material of 1g per m 2 thereof, of the sum of the peak heights of
the X-ray diffraction lines attributable to silver behenate at
Bragg angles, 2Θ, of 6.01°, 7.56°, 9.12°, 10.66°, 12.12° and
13.62° to the sum of the peak heights of the X-ray diffraction
lines at Bragg angles, 2Θ, of 25.60°, 35.16° and 43.40° of NIST
standard 1976, rhombohedral Al 2 O 3 , determined with the same X-ray
diffractometer in the same state of adjustment, is greater
than 1.2.
Claim 5
Dependent Claim
18 words
Recording material according to any of the preceding claims,
wherein said thermosensitive element further comprises a toning
agent.
Claim 6
Dependent Claim
19 words
Recording material according to any of the preceding claims,
wherein said thermosensitive element is provided with a
protective layer.
Claim 7
Dependent Claim
33 words
Recording material according to any of the preceding claims,
wherein said thermosensitive element further comprises a
photosensitive species capable upon exposure of forming a
species capable of catalyzing reduction of said silver behenate.
Claim 8
Dependent Claim
192 words
A production process for particles of substantially light-insensitive
organic silver salt comprising silver behenate
comprising the steps of: i) producing a solution or dispersion,
A, comprising an alkali metal or ammonium salt of an organic
compound with at least one acidic hydrogen atom comprising
behenic acid in a mixture of water and an organic solvent at a
temperature at which particles of said substantially light-insensitive
organic silver salt comprising silver behenate do
not undergo reduction; and ii) adding a quantity of an aqueous
solution, B, of a silver salt containing an equal number of
silver ions to the alkali or ammonium ions in said solution or
dispersion A; characterized in that the initial mixing number
during said addition of said aqueous solution B to said solution
or dispersion A is greater than or equal to 2x10 -4 during said
production of said particles of substantially light-insensitive
organic silver salt comprising silver behenate, said mixing
number being the ratio of the molar rate at which said silver
salt is supplied to said solution A in a reactor to the molar
rate at which said alkali or ammonium salt is circulated in said
reactor.
Claim 9
Dependent Claim
47 words
Production process according to claim 8, wherein said solution
or dispersion A has a molar concentration of alkali metal or
ammonium salt of organic compound with at least one acidic
hydrogen atom comprising behenic acid in said mixture of water
and an organic solvent greater than 0.022.
Claim 10
Dependent Claim
124 words
A production process for a dispersion of particles of
substantially light-insensitive organic silver salt including
silver behenate in an aqueous medium comprising the steps of: i)
producing an aqueous dispersion of one or more organic acids
including behenic acid and an anionic surfactant; ii)
substantially neutralizing said organic acids with aqueous
alkali thereby forming organic acid salts including a behenic
acid salt; (iii) adding an aqueous solution of a silver salt to
completely convert said organic acid salts into their silver
salts including silver behenate, characterized in that said
anionic surfactant is present in a molar ratio with respect to
organic acid greater than 0.15 and said silver salt is added at
a rate between 0.025mol/mol organic silver salt·min and
2.25mol/mol organic silver salt·min.
Claim 11
Dependent Claim
17 words
Production process according to claim 10, wherein said anionic
surfactant is a salt of an alkaryl sulfonate.
Claim 12
Dependent Claim
19 words
Production process according to claim 11, wherein said salt of
an alkarylsulfonate is a salt of an alkylbenzene sulfonate.
Claim 13
Dependent Claim
22 words
Production process according to any of claims 10 to 12, wherein
said silver organic salt including silver behenate is subject to
ultrafiltration.
Claim 14
Dependent Claim
65 words
A recording process comprising the steps of: (i) bringing an
outermost layer of a recording material according to any of
claims 1 to 8 into proximity with a heat source; and (ii)
applying heat from said heat source imagewise heating to said
recording material while maintaining proximity to said heat
source to produce an image; and (iii) removing said recording
material from said heat source.
Claim 15
Dependent Claim
17 words
A recording process according to claim 14, wherein said heat
source is a thin film thermal head.
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