Image recording method
Provided is an image recording method including applying an ink containing water, a resin X, and a colorant onto a resin base material A which has a specific distortion rate and to which a tension is applied, to obtain an image, heating the image to a temperature Td and drying the image, and cooling the image to a temperature Tr, in which σ total calculated by Equation (1) is 40 kgf/cm 2 or less. E(T d ) represents an elastic modulus of the resin X at the temperature T d , ε(T d ) represents an expansion coefficient of the resin base material A under specific conditions, E(T) represents an elastic modulus of the resin X at a temperature T of the image in the cooling, α r (T) represents a linear expansion coefficient of the resin X at the temperature T, and α s (T) represents a linear expansion coefficient of the resin base material A under specific conditions. σ total =|σ dry +σ cool | Equation (1) σ dry =E ( T d )ε( T d ) Equation (2) σ cool =∫ T r T d E ( T )(α r ( T )−α s ( T )) dT Equation (3)
1. An image recording method comprising:
preparing a resin base material A in which an absolute value of a distortion rate represented by Equation (a1) in a case where the base material is heated from 25° C. to 60° C. at a temperature increasing rate of 5° C./min and maintained at 60° C. for 2 minutes in a state where a tension of 30 N/m is applied thereto, and the base material is cooled to 25° C. at a temperature decreasing rate of 5° C./min in a state where a tension of 30 N/m is applied thereto is 0.05% or greater;
preparing an ink containing water, a resin X, and a colorant;
applying the ink onto the resin base material A to which a tension S 1 of 10 N/m or greater is applied, to obtain an image;
heating and drying the image to a temperature T d of 50° C. or higher in a state where a tension S 2 of 10 N/m or greater is applied to the resin base material A; and
cooling the image after the drying to a temperature T r of 30° C. or lower in a state where a tension S 3 of 10 N/m or greater is applied to the resin base material A,
wherein σ total to be calculated by Equation (1) is 40 kgf/cm 2 or less,
distortion rate (%)=((length of resin base material in tension application direction at end of cooling−length thereof in tension application direction at start of heating)/length thereof in tension application direction at start of heating)×100 Equation (a1)
σ total =|σ dry +σ cool | Equation (1)
σ dry =E ( T d )ε( T d ) Equation (2)
σ cool =∫E T r T d ( T )(α r ( T )−α s ( T )) dT Equation (3)
in Equation (1), σ dry is calculated by Equation (2), and σ cool is calculated by Equation (3),
in Equation (2),
E(T d ) represents an elastic modulus of the resin X at the temperature T d which is expressed in a unit of kgf/cm 2 ,
ε(T d ) represents an expansion coefficient of the length of the resin base material A represented by Equation (a2) in the tension application direction in a case where the base material is heated from 25° C. to the temperature T d and maintained at the temperature T d in a state where the tension S 2 is applied thereto, and the base material is cooled to 25° C. in a state where the tension S 2 is applied thereto,
expansion coefficient of length of resin base material A in tension application direction=(length of resin base material in tension application direction at end of cooling−length thereof in tension application direction at start of heating)/length thereof in tension application direction at start of heating Equation (a2)
in Equation (3),
E(T) represents an elastic modulus of the resin X at a temperature T of the image in the cooling which is expressed in the unit of kgf/cm 2 ,
α r (T) represents a linear expansion coefficient of the resin X at the temperature T,
α s (T) represents a linear expansion coefficient of the resin base material A in the tension application direction in a state where the tension S 3 is applied thereto at the temperature T,
T d represents the temperature T d , and
T r represents the temperature T r .
2. The image recording method according to claim 1 ,
wherein σ total is 30 kgf/cm 2 or less.
3. The image recording method according to claim 1 ,
wherein the tension S 1 , the tension S 2 , and the tension S 3 are each independently in a range of 10 N/m to 60 N/m.
4. The image recording method according to claim 1 ,
wherein the resin base material A has a thickness of 12 nm to 60 nm.
5. The image recording method according to claim 1 ,
wherein the resin base material A is a polypropylene base material or a nylon base material.
6. The image recording method according to claim 1 ,
wherein the resin X is at least one of an acrylic resin or a polyester resin.
7. The image recording method according to claim 1 ,
wherein the resin base material A has a long film shape, and
the application of the ink in the applying, the drying of the image in the drying, and the cooling of the image in the cooling are performed while the resin base material A is transported in a longitudinal direction of the resin base material A using a roll-to-roll method.