Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1998-02-10
1999-11-16
Acquah, Samuel A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
525437, 524601, 524602, 524605, 524608, 106 3113, 106 3115, 106 3127, 106 3157, 106 3159, 4273855, 427394, 428480, C08L 6702, C09D 1112
Patent
active
059859881
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a thermal ink jet printing process and to inks.
Inks containing water-soluble dyes, water and organic solvents are well known. For example Zeneca's British Patent application No. 2,275,479 describes such inks and their utility in ink jet printing ("IJP").
Inks containing a water-insoluble acrylic polymer and an oil soluble dye are described in U.S. Pat. No. 4,680,332. These inks are suitable for piezoelectric IJP but when they are used in thermal IJP they tend to block printer nozzles giving poor quality images which have a "quilted" appearance.
WO91/06608 describes aqueous inks containing a polyester, water, a pigment and a wax. Whilst these inks are useful in printing presses, the pigments they contain require intensive and expensive milling to make them fine enough to pass through ink jet printer heads and the pigments have a tendency to settle out from the ink on standing for long periods. Furthermore, images formed from inks containing insoluble pigments are generally opaque and this limits their usefulness on overhead projector slides.
There is a need for inks which are suitable for thermal IJP, have high colour strength and give clear, high water-fast images when printed on a substrate.
According to the present invention there is provided a process for coloration of a substrate comprising printing an ink onto the substrate using a thermal ink jet printer, characterised in that the ink comprises water and a water-dissipatable polyester dyed using a disperse dye or a solvent soluble dye.
The water-dissipatable polyester preferably bears ionised carboxy and/or sulphonate groups, especially ionised sulphonate groups, because these assist water dissipatability of the polyester. Such groups can be chain pendant and/or terminal in the polyester.
The water-dissipatable polyester can be prepared using conventional polymerisation procedures known to be effective for polyester synthesis. Thus, it is well known that polyesters contain carbonyloxy (i.e --C(.dbd.O)--O--) linking groups and may be prepared by a condensation polymerisation process in which an acid component (including ester-forming derivatives thereof) is reacted with a hydroxyl component. The acid component may be selected from one or more polybasic carboxylic acids, e.g. di- and tri-carboxylic acids or ester-forming derivatives thereof, for example acid halides, anhydrides or esters. The hydroxyl component may be one or more polyhydric alcohols or phenols (polyols), for example, diols, triols, etc. (It is to be understood, however, that the polyester may contain, if desired, a proportion of carbonylamino linking groups --C(.dbd.O)--NH-- (i.e. amide linking groups) by including an appropriate amino functional reactant as part of the "hydroxyl component"; such as amide linkages). The reaction to form a polyester may be conducted in one or more stages. It is also possible to introduce in-chain unsaturation into the polyester by, for example, employing as part of the acid component an olefinically unsaturated dicarboxylic acid or anhydride.
Polyesters bearing ionised sulphonate groups may be prepared by using at least one monomer having two or more functional groups which will readily undergo an ester condensation reaction (e.g carboxyl groups, hydroxyl groups or esterifiable derivatives thereof) and one or more sulphonic acid groups (for subsequent neutralisation after polyester formation) or ionised sulphonate groups (i.e. neutralisation of the sulphonic acid groups already having been effected in the monomer) in the synthesis of the polyester. In some cases it is not necessary to neutralise sulphonic acid groups since they may be sufficiently strong acid groups as to be considerably ionised in water even without the addition of base. Often, the sulphonic acid or ionised sulphonate containing monomer is a dicarboxylic acid monomer having at least one ionised sulphonate substituent (thereby avoiding any need to effect neutralisation subsequent to polyester formation). (Alternatively, alkyl carboxylic acid ester groups may b
REFERENCES:
patent: 5292855 (1994-03-01), Krutak et al.
Acquah Samuel A.
Zeneca Limited
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