Maintenance liquid and maintenance method

Abstract

There is provided a maintenance liquid, which is used in maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing the acyl phosphine oxide-based photopolymerization initiator toward an attachment object, including a polymerizable compound in which a saturation solubility of an acyl phosphine oxide-based photopolymerization initiator at 20° C. is equal to or greater than 5.0% by mass.

What is claimed is: 
     
         1 . A maintenance liquid which is used in maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing the acyl phosphine oxide-based photopolymerization initiator toward an attachment object comprising:
 a polymerizable compound in which a saturation solubility of an acyl phosphine oxide-based photopolymerization initiator at 20° C. is equal to or greater than 5.0% by mass.   
     
     
         2 . The maintenance liquid according to  claim 1 ,
 wherein the polymerizable compound includes at least any one of vinyl ether group-containing (meth)acrylic acid ester represented by the following general formula (1) and a monofunctional (meth)acrylate compound having an aromatic ring.
   CH 2 ═CR 1 —COOR 2 —O—CH═CH—R 3   (1)
 
   
       (In the formula (1), R 1  represents a hydrogen atom or a methyl group, R 2  represents a divalent organic residue having 2 to 20 carbon atoms, and R 3  represents a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms.) 
     
     
         3 . The maintenance liquid according to  claim 1 ,
 wherein the viscosity of the polymerizable compound at 20° C. is equal to or less than 30 mPa·s.   
     
     
         4 . The maintenance liquid according to  claim 1 ,
 wherein the content of the polymerizable compound is equal to or greater than 40% by mass with respect to the total amount of the maintenance liquid.   
     
     
         5 . The maintenance liquid according to  claim 1 ,
 wherein the viscosity at 20° C. is equal to or less than 20 mPa·s.   
     
     
         6 . The maintenance liquid according to  claim 1 ,
 wherein the viscosity at 20° C. is lower than the viscosity of the ultraviolet ray curable-type composition at 20° C. by equal to or greater than 5 mPa·s.   
     
     
         7 . The maintenance liquid according to  claim 1 ,
 wherein the ultraviolet ray curable-type composition includes the polymerizable compound, and the content of the polymerizable compound in the maintenance liquid is larger than the content of the polymerizable compound in the ultraviolet ray curable-type composition by equal to or greater than 10% by mass.   
     
     
         8 . The maintenance liquid according to  claim 1 ,
 wherein the saturation solubility of the acyl phosphine oxide-based photopolymerization initiator at 20° C. with respect to the polymerizable compound is equal to or greater than 8.0% by mass.   
     
     
         9 . The maintenance liquid according to  claim 1 , further comprising:
 at least any one of a silicone-based surfactant and a fluorine-based surfactant.   
     
     
         10 . The maintenance liquid according to  claim 1 ,
 wherein the molecular weight of the polymerizable compound is equal to or greater than 170.   
     
     
         11 . The maintenance liquid according to  claim 1 ,
 wherein the content of the acyl phosphine oxide-based photopolymerization initiator in the ultraviolet ray curable-type composition is equal to or greater than 5.0% by mass.   
     
     
         12 . The maintenance liquid according to  claim 1 ,
 wherein a solubility parameter is equal to or greater than 5.0.   
     
     
         13 . The maintenance liquid according to  claim 1 ,
 wherein the saturation solubility is a saturation solubility of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide at 20° C.   
     
     
         14 . A maintenance method, comprising:
 performing maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing an acyl phosphine oxide-based photopolymerization initiator toward an attachment object using the maintenance liquid according to  claim 1 .   
     
     
         15 . A maintenance method, comprising:
 performing maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing an acyl phosphine oxide-based photopolymerization initiator toward an attachment object using the maintenance liquid according to  claim 2 .   
     
     
         16 . A maintenance method, comprising:
 performing maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing an acyl phosphine oxide-based photopolymerization initiator toward an attachment object using the maintenance liquid according to  claim 3 .   
     
     
         17 . A maintenance method, comprising:
 performing maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing an acyl phosphine oxide-based photopolymerization initiator toward an attachment object using the maintenance liquid according to  claim 4 .   
     
     
         18 . A maintenance method, comprising:
 performing maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing an acyl phosphine oxide-based photopolymerization initiator toward an attachment object using the maintenance liquid according to  claim 5 .   
     
     
         19 . The maintenance method according to  claim 14 ,
 wherein the device has an ultraviolet ray emitting diode for irradiating the discharged ultraviolet ray curable-type composition with ultraviolet rays, and the ultraviolet ray emitting element has an emission peak wavelength in a range of 360 nm to 420 nm.   
     
     
         20 . The maintenance method according to  claim 14 ,
 wherein the device is equipped with a heating mechanism for heating the ultraviolet ray curable-type composition, and discharges the heated composition.