Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
1998-07-15
2001-07-03
Cooney, John (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C106S031130, C106S031430, C528S068000, C528S069000, C528S085000
Reexamination Certificate
active
06255432
ABSTRACT:
The present invention relates to the formulation of hot melt ink jet base materials (hereinafter referred to as “ink jet vehicles”) with a view to improving their compatibility with viscosity modifying additives.
Ink jet printing generally comprises forming a patterned array of droplets of an ink upon a substrate to form the desired indicia on the substrate. In a hot melt ink jet printing process, the ink is one which is normally solid at ambient temperatures and which is applied to the substrate in molten form so that the droplets solidify on cooling on the substrate.
Typically, the ink employed in hot melt ink jet printing comprises a fusible carrier together with a colourant, i.e. a pigment or dyestuff. Suitable materials for use as or in the vehicles for inks for hot melt ink jet printing (hereinafter, simply, “hot melt inks”) should be relatively hard and non-tacky at ambient temperatures whilst being capable of melted to form inks. Suitably, they have a melting point of at least 65° C.
Patent Specification WO 94/14902 describes the use of certain urethane oligomers as hot melt ink vehicles. These oligomers are the reaction products of diisocyanates with a monohydric alcohol component, optionally followed by another monohydric component or a dihydric alcohol component followed by a monohydric alcohol component. These materials have melting points in excess of 65° C., low melt viscosities and good colour and viscosity stabilities at elevated temperatures. However, they are compatible with only a limited number of viscosity modifiers. This drawback may limit the range of applications of such materials, where certain specific properties, not possessed by the materials alone, are required.
A new class of hot melt ink jet vehicles has now been devised, which overcomes the aforementioned limitation in the range of possible applications. Thus, in accordance with the present invention, there may be used as hot melt ink jet vehicles, the reaction products of a mono- or diisocyanate and one or more functional amides. The present invention also provides the use of a urea or urethane compound having a melting point greater than 65° C., as a hot melt ink jet vehicle, the urea or urethane compound being the reaction product of a mono- or diisocyanate and a functional amide.
According to one embodiment of the present invention, there is provided a material suitable for use in a hot melt ink, the material being obtainable by reacting a mono- or diisocyanate with one or more functional amide materials which are the reaction products of:
(a) (i) one or more hydroxy functional primary or secondary amines; or
(ii) one or more diprimary diamines; or
(iii) a mixture of components (i) and (ii); and
(b) a monofunctional carboxylic acid, a hydroxy carboxylic acid or difunctional carboxylic acid or a mixture of any two or more thereof.
Very preferably, materials according to the present invention have a a melting point in excess of 65° C. They also have good thermal colour and viscosity stability as well as improved compatibility with common viscosity modifiers.
More specifically, preferred materials according to the present invention may be produced by reacting a mono- or di-functional aliphatic or aromatic isocyanate with an at least stoichiometric amount of:
(i) the reaction product of one equivalent of a diprimary diamine component with one equivalent of a monocarboxylic acid and one equivalent of a hydroxy functional monocarboxylic acid;
(ii) the reaction product of one equivalent of a diprimary diamine component with one equivalent of a monocarboxylic acid;
(iii) the reaction product of one equivalent of a primary monoamine with hydroxy functionality, with one equivalent of a monocarboxylic acid; or
(iv) the reaction products (i) or (ii), but where an equivalent of acid functionality is made up of a proportion of monocarboxylic acid, dicarboxylic acid and/or hydroxy functional monocarboxylic acids.
The amides produced by the reactions described above may be hydroxy or amine functional, depending on the proportions and type of reagent used. Thus the reaction products obtained from these amides and the isocyanate materials will be urethane or urea compounds depending on whether the isocyanate groups react with hydroxy or amine groups respectively.
As noted above, it is greatly preferred that materials according to the present invention (hereinafter referred to as urethane-amides or urea-amides) have a melting point greater than 65° C. (as determined by the ball and ring method). It should be noted that not all materials obtainable by the processes outlined above have melting points greater than 65° C. Our experiments have shown that there is a wide range of melting points and that attempts to predict the melting point, by taking molecular weight or component reagents into account, are fruitless. However, of course it is simple to measure the melting point once the material has been made, by simple routine and trial.
Suitable isocyanates for use in the preparation of the urethane- and urea-amides include octadecylmonoisocyanate, toluene diisocyanate, diphenylmethane-4,4′-diisocyanate (MDI), hexamethylene-1,6-diisocyanate, naphthalene-1,5-diisocyanate, 3,3′-dimethyl-4,4′-biphenyl diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate and tetramethylene xylene diisocyanate. Of these isocyanates the aliphatic materials are generally preferred to the aromatic ones for reasons of heat and viscosity stability. In particular isophorone diisocyanate, trimethylhexamethylene diisocyanate and octadecyl monoisocyanate have been found to be particularly suitable for this application.
Diprimary diamines which may be used to produce the amides for isocyanate adduction, including ethylene diamine, neopentane diamine, 2,4,4-trimethylhexandiamine, 2-butyl-2-ethyl 1,5 pentane diamine, 1,3-diaminopentane, isophorone diamine and 2 methyl 1,5 pentamethylene diamine. Hydroxy functional primary and secondary amines which may be used are ethanolamine, diethanolamine and n-methyl diethanolamine. In particular ethylene diamine is suitable in this type of formulation.
Monocarboxylic acids which are suitable for this application are stearic acid, acetic acid, 3,5,5-trimethylhexanoic acid, decanoic acid, propanoic, acid 2,2 dimethyl propionic acid, isooctanoic acid, isoheptanoic acid, isobutynic acid, or isodecanoic acid. Stearic and 3,5,5-trimethylhexanoic acids have proved particularly suitable in this application. Dimer acids are suitable difunctional carboxylic acids.
Hydroxy functional monocarboxylic acids which may be used include 12-hydroxy stearic acid, 12-hydroxydodecanoic acid, 2-hydroxyhexanoic acid, 16-hydroxyhexadecanoic acid and 2-hydroxyisobutyric acid. 12-hydroxystearic acid and 12-hydroxydodecanoic acid have proved particularly useful in this application.
The amide components of the hot melt ink vehicle typically have melting points (ball and ring) of >50° C. and viscosities <200 centipoise at 125° C.
The condensation reaction used to produce the amide component of the urethane- and urea-amides proceeds without need of a catalyst. The reaction of the amide with the isocyanate component may also be carried out without a catalyst, but catalysts such as dibutyl tin dilaurate and stannous octoate may be used to ensure full reaction of the isocyanate fraction.
The final average molecular weight of the urethane- or urea-amides is typically from 400 to 2000, preferably from 800 to 1400. These materials having melting points of from room temperature (e.g. 20° C.) to 130° C. and melt viscosities of from 10 to 800 centipoise at 125° C.
For some applications of hot melt inks it is advantageous if the urethane- or urea-amides are transparent. As with the melting points described previously, it is impossible to predict which particular mix of reagents will produce a clear product. Again determination of suitable materials is by simple trial and experiment. Similarly, the viscosity of the materials at elevated temperatures is not easily predicted, materials with viscosities lo
Evans Philippa Catherine
Hall Stephen Anthony
Coates Brothers PLC
Cooney John
Ostrolenk Faber Gerb & Soffen, LLP
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