1. A radiation-curable, aqueous dispersion based on polyurethane acrylates (i) comprising as structural components
A) an oligomeric or polymeric compound comprising an isocyanate-reactive group and a radically copolymerisable group;
B) optionally a monomeric compound other than A comprising a hydroxy functional group and a (meth)acrylate group;
C) a polyester polyol obtained from
C1) an aliphatic diol comprising from 2 to 4 carbon atoms between the two OH functional groups of said aliphatic diol andor an aliphatic triol, and
C2) an aromatic di- andor tri-carboxylic acid;
D) optionally a polyol other than A, B, and C;
E) a compound comprising an isocyanate-reactive group towards and a non-ionic group, an ionic group, or a group capable of forming an ionic group, wherein said compound has a dispersing action;
F) an organic polyisocyanate;
G) optionally a compound other than A, B, C, D, and E comprising an isocyanate-reactive group.
2. The radiation-curable, aqueous dispersion of claim 1, further comprising a reactive diluent (ii) comprising a radically polymerisable group.
3. The radiation-curable, aqueous dispersion of claim 1, wherein structural component C is used in an amount of from 5 to 75 weight %, wherein the sum of the amounts of components A, B, C, D, E, F, and G equals 100 weight %.
4. The radiation-curable, aqueous dispersion of claim 1, wherein structural component C has an OH number in the range of from 20 to 500 mg KOHg of substance.
5. The radiation-curable, aqueous dispersion of claim 1, wherein structural component A is selected from the group consisting of polyester(meth)acrylates comprising hydroxyl groups, polyether(meth)acrylates comprising hydroxyl groups, polyether ester(meth)acrylates comprising hydroxyl groups, and polyepoxy(meth)acrylates comprising hydroxyl groups.
6. The radiation-curable, aqueous dispersion of claim 1, wherein component C1 is selected from the group consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 2-ethyl-2-butylpropanediol, 1,3-butanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-butanediol, trimethylolethane, trimethylolpropane, trimethylolbutane, glycerol, castor oil, and mixtures thereof and component C2 is selected from the group consisting of phthalic acid, phthalic anhydride, isophthalic acid, isophthalic anhydride, terephthalic acid, terephthalic anhydride, trimellitic acid, trimellitic anhydride, and mixtures thereof.
7. The radiation-curable, aqueous dispersion of claim 1, wherein component C1 is selected from the group consisting of 1,2-ethanediol, 1,2-propanediol, neopentyl glycol, trimethylolpropane, and mixtures thereof, and component C2 is selected from the group consisting of isophthalic acid, terephthalic acid, and mixtures thereof.
8. The radiation-curable, aqueous dispersion of claim 1, wherein structural component E is selected from the group consisting of 2-(2-amino-ethylamino)ethanesulfonic acid, 3-(cyclohexylamino)propane-1-sulfonic acid, the addition product of isophoronediamine and acrylic acid, hydroxypivalic acid, dimethylolpropionic acid, triethanolamine, tripropanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, monofunctional mixed polyalkylene oxide polyethers containing at least 40 mol % ethylene oxide units and no more than 60 mol % propylene oxide units, and mixtures thereof.
9. The radiation-curable, aqueous dispersion of claim 1, wherein structural component F is selected from the group consisting of the polyisocyanates 1,6-hexamethylene diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4\u2032-diisocyanato-dicyclohexylmethane, and mixtures thereof; homologues of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane with biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione, andor uretdione groups, oligomers of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane with biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione, andor uretdione groups, homologues of 4,4\u2032-diisocyanato-dicyclohexylmethane with biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione, andor uretdione groups, oligomers of 4,4\u2032-diisocyanato-dicyclohexylmethane with biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione, andor uretdione groups, and mixtures thereof; and mixtures of said homologues andor said oligomers with said polyisocyanates.
10. A process for preparing the radiation-curable, aqueous dispersion of claim 1, comprising
reacting components A, B, C, D, and E in one or more reaction steps with component F to obtain a polyurethane acrylate prepolymer (i), wherein a neutralising agent for producing ionic groups is optionally added before, during, or after the preparation of said polyurethane acrylate prepolymer;
adding water to said polyurethane acrylate prepolymer or converting said polyurethane acrylate prepolymer into an aqueous initial charge to obtain a dispersion; and
optionally chain extending said polyurethane acrylate prepolymer with component G before, during or after obtaining said dispersion.
11. The process of claim 10, wherein the molar ratios of isocyanate groups in F to isocyanate-reactive groups in A, B, C, D and E is from 0.8:1 to 2.5:1.
12. The process of claim 10, wherein one more reactive diluents having at least one radically polymerisable group (component ii) isare added as a further component.
13. A coating, lacquer, or adhesive comprising the radiation-curable, aqueous dispersion of claim 1.
14. A coating composition comprising the radiation-curable, aqueous dispersion of claim 1, a crosslinker based on an amino resin, a blocked polyisocyanate, a non-blocked polyisocyanate, a polyaziridine andor a polycarbodiimide, andor a further dispersion.
15. A substrate coated with coating composition of claim 14.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A micro-electromechanical ink ejection mechanism for a printer, the ink ejection mechanism comprising:
a substrate that defines an ink inlet;
a drive circuitry layer positioned on the substrate;
an elongate thermal bend actuator connected at a fixed end to the drive circuitry layer and configured to be displaced reciprocally with respect to the substrate on receipt of a signal from the drive circuitry layer;
an ink ejection member that spans the ink inlet and is operatively connected to the bend actuator to be reciprocally displaceable with respect to the substrate upon reciprocal displacement of the bend actuator;
a motion transfer structure interposed between the actuator and the ink ejection member to transfer movement of the actuator to the ink ejection member; and
a nozzle chamber structure positioned on the substrate and defining an ink chamber in which the ink ejection member is positioned and a region in which the bend actuator is positioned, such that the motion transfer structure is interposed between the ink chamber and said region, the nozzle chamber structure further defining an ink ejection port in fluid communication with the ink chamber such that said reciprocal movement of the ink ejection member serves to eject ink from the ink ejection port.
2. A micro-electromechanical ink ejection mechanism as claimed in claim 1, in which the motion transfer structure is in the form of a lever structure with an effort portion being connected to the bend actuator and a work portion being connected to the ink ejection member.
3. A micro-electromechanical ink ejection mechanism as claimed in claim 2, in which a base extends from the substrate, the lever structure being mounted on the base.
4. A micro-electromechanical ink ejection mechanism as claimed in claim 3, in which the lever structure is connected to the nozzle chamber structure with opposed torsion members.
5. A micro-electromechanical ink ejection mechanism as claimed in claim 4, in which the nozzle chamber structure, the lever structure and the torsion members together define a roof structure that defines the ink ejection port and also overlies the thermal bend actuator.
6. A micro-electromechanical ink ejection mechanism as claimed in claim 5, in which the roof structure defines a raised rim surrounding the ink ejection port.
7. A micro-electromechanical ink ejection mechanism as claimed in claim 6, in which a plurality of radially extending recesses is defined in the roof structure about the rim to contain radial ink flow as a result of ink escaping past the nozzle rim.