Image recording method
Provided is an image recording method including applying a pretreatment liquid containing water and a resin X and an ink containing water 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 T d and drying the image, and cooling the image to a temperature T r , 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 ) ɛ ( 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 a pretreatment liquid containing water and a resin X;
preparing an ink containing water and a colorant;
sequentially applying the pretreatment liquid and the ink onto the resin base material A to which a tension S1 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 S2 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 S3 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
)
ɛ
(
T
d
)
Equation
(
2
)
σ
cool
=
∫
T
r
T
d
E
(
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 S2 is applied thereto, and the base material is cooled to 25° C. in a state where the tension S2 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 S3 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 S1, the tension S2, and the tension S3 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 μm to 60 μm.
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 pretreatment liquid and 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.