Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
1999-04-12
2001-06-05
Wood, Elizabeth D. (Department: 1755)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
C430S464000, C430S467000, C430S477000, C430S479000, C502S041000, C502S071000, C502S077000, C502S078000, C502S079000, C502S085000, C502S087000, C502S202000, C502S208000, C502S214000, C502S216000, C502S217000, C502S232000, C502S240000, C502S242000, C502S243000, C502S250000, C502S251000, C502S253000, C502S263000
Reexamination Certificate
active
06242167
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to a color developer composition which is designed to be used with recording systems which employ colorless electron donating materials to form images.
Recording materials utilizing developer materials to produce colored images from colorless or substantially colorless electron donating materials are well-known. Specific examples of such recording materials include pressure sensitive carbonless copying paper, heat-sensitive recording paper, electrothermographic recording paper, Cycolor® photographic materials and the like. They are described in more detail in U.S. Pat. Nos. 2,712,507; 2,730,456; 2,730,457; 3,418,250; 3,432,327; 3,981,821; 3,993,831; 3,996,156; 3,996,405 and 4,000,087. These papers include a developer sheet (also referred to as a CF (coated front) sheet) comprising a substrate coated with an electron acceptor which reacts with a leuco dye transferred to the surface of the developer sheet to form an image thereon.
Much research has been directed to developing new and improved developers for use in the aforementioned recording materials. Representative examples of the developers that have been used include phenol derivatives and phenolic resins, biphenols, methylene bis-diphenols, phenol-formaldehyde novolak resins, metal processed novolak resins, salicylic acid derivatives and salts. See U.S. Pat. No. 3,934,070 to Kimura teaching salicyclic acid derivatives; U.S. Pat. No. 3,244,550 to Farnham teaching biphenols, diphenols, and resinous products containing them, and U.S. Pat. No. 3,244,549 to Farnham teaching phenol derivatives. Representative examples of phenol-formaldehyde condensates previously used in the art are described in numerous patents, including U.S. Pat. No. 3,672,935. Among color developers, phenol-formaldehyde condensates have been widely used because they exhibit excellent color development, good coating properties (rheology) and good water resistance. However, phenolic resins are somewhat colored materials and become even more colored as they are exposed to ambient conditions. Such discoloration is a very undesirable attribute in imaging systems where aesthetic appearance is of extreme importance. Fading of the image when exposed to extreme temperatures and humidity is also an undesirable trait of the currently developer materials. Therefore, it is a principal object of the present invention to provide an improved developer composition for use with recording materials which employ leuco dyes such as carbonless copy paper and photo imaging systems which overcome some of the deficiencies of prior art developers.
SUMMARY OF THE INVENTION
The invention is based upon the discovery that molecular sieves and certain alkali metal-containing water insoluble organic oxides, when treated with an acid, can be used as a developer for color formers in recording materials.
The developer material of the present invention may be used in any recording system in which a color precursor is reacted with a Lewis acid or electron accepting color developer. Such recording systems include pressure sensitive recording materials like carbonless paper, thermal recording systems and photosensitive systems like the Cycolor® imaging system described in U.S. Pat. No. 4,399,209 and related patents. It may be used in a self-contained system in which the color precursor and developer are in the same or different layers but present on the same support or it may be used in a transfer system containing a donor or imaging sheet and a developer sheet wherein the donor or imaging sheet contains an image-forming agent capable of reacting with the developer material to form an image. To produce a visible image, the donor or imaging sheet is assembled with the developer sheet and pressure is applied to the sheets to cause transfer of the image-forming agent to the developer sheet. It is particularly envisioned that the developer material of the present invention be coated on a substrate sheet to provide a developer sheet which is then used in association with an imaging sheet containing photosensitive microcapsules containing an image-forming agent. The developer material may also be utilized in a self-contained imaging format.
DETAILED DESCRIPTION
In accordance with the present invention, a new color developer has been discovered which overcomes many of the drawbacks of the currently used developers.
In one embodiment of the invention, the developer is an acid-treated, alkali metal-modified, inorganic oxide such as silicate, aluminate, borate, borosilicate, phosphate, sulfate, silicon oxide, etc. A typical example of these developers are compounds of the general formula:
L
w
+a
M
y
+b
(X
p
O
n
)
z
−c
where L is lithium, sodium, potassium or hydrogen; M is zinc, magnesium or calcium; X is silicon, boron, phosphorus, aluminum, sulfur, titanium or tin; O is oxygen; n is 3 to 25 and p is 1 to 6; and each of w, y and z represents a numeral wherein w(a)+y(b)=z(c) such that the compound is electronically neutral. The general formula is a simplified definition of the compounds. More complex materials are possible because of the tendency of some of the anion forming atoms X to create condensed oxides. Examples of oxide anion structures include (Si
3
O
9
)
−6
, (Si
4
O
12
)
−8
, (Si
8
O
24
)
−16
, (Si
2
O
5
)
−2
, (Si
6
O
17
)
−4
, (B
2
O
5
)
−4
, (B
3
O
6
)
−3
, (P
2
O
7
)
−4
, (P
3
O
10
)
−5
, (P
3
O
9
)
−3
, (S
2
O
6
)
−2
, etc.
In another embodiment of the invention, the developer is an acid-treated molecular sieve. Molecular sieves typically comprise a variety of compositions such as silicates, aluminosilicates, aluminophosphates, transitional aluminates, and the like. The inorganic oxide and molecular sieve should be essentially water insoluble, i.e., less than 1% soluble in water.
The alkali metal-modified inorganic oxides can be prepared by a process which typically consists of heating the reactants together in air in a temperature range of about 200 to 1200° C. for several hours, the temperature used being dependent on the nature of the reactants. After this reaction is complete an acid treatment as discussed later is performed on the reaction product.
A hydrothermal crystallization process is used for preparing the molecular sieves. This process typically involves of mixing the reactants in a solvent, usually water, and then heating the mixture in a closed reactor at 100 to 300° C. for several hours. This reaction is typically carried out in the presence of a templating agent, which provides a specific structure. Following the completion of this reaction, the product is treated with acid. This treatment is followed by a calcining operation. A variety of templates have been used to synthesize molecular sieves from molecular sieve precursors such as the silicate, aluminosilicate, and borosilicate family. Preferably, the molecular sieve precursor is a silicate such as tetraethylorthosilicate (TEOS), tetramethylammonium silicate, tetraethylammonium silicate, etc. Molecular sieves are prepared by crystallization in an aqueous reaction mixture containing an inorganic templating agent such as a nitrogen-containing organo-cation. By varying the synthesis conditions and the composition of the reaction mixture, different zeolites can be formed. The role of templating agents in the preparation of molecular sieves is well known. The positive charge of the organocation templating species is believed to interact with the negatively charged silicate subunits, resulting in the crystallization of the resultant molecular sieve. The organic cation also greatly affects the characteristics of the gel. These effects can range from modifying the gel pH to altering the interactions of the various components via changes in hydration (and thus solubilities of reagents) and other physical properties of the gel.
It has been observed that many of the organocations which have been used as templates for zeolite synthesis are conformationally flexible. These molecules can
Chaloner-Gill Benjamin
Shackle Dale R.
Rentech Inc.
Thompson Hine & Flory LLP
Wood Elizabeth D.
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