Process for producing laminate, and laminate
To provide a laminate excellent in alkali resistance and interlaminar strength at high temperature, and a process for producing the laminate. A process for producing a laminate, comprising producing a non-crosslinked laminate having a layer of a first composition containing a copolymer having fluorine atoms and a layer of a second composition containing a non-fluorinated elastic polymer, and crosslinking the first composition and the second composition to produce a laminate having a first layer formed of a crosslinked product of the first composition and a second layer formed of a crosslinked product of the second composition, wherein when the first composition and the second composition contains a common crosslinking aid, the absolute value of the crosslinking rate difference between the first composition and the second composition is at most 0.30.
1. A process for producing a laminate, comprising
producing a non-crosslinked laminate having a layer of a first composition containing a fluorinated elastic polymer comprising a copolymer having units based on tetrafluoroethylene and units based on propylene or a copolymer having units based on tetrafluoroethylene and units based on a perfluoro(alkyl vinyl ether), a crosslinking agent and a crosslinking aid, and a layer of a second composition containing a non-fluorinated elastic polymer and a crosslinking agent and optionally a crosslinking aid, and
crosslinking the first composition and the second composition to produce a laminate having a first layer formed of a crosslinked product of the first composition and a second layer formed of a crosslinked product of the second composition,
wherein the absolute value of the crosslinking rate difference between the first composition and the second composition as calculated in accordance with the following formula 1 is at most 0.30:
crosslinking rate difference=[1/( t 90A −t 2A )−1/( t 90B −t 2B )]×( t 90A −t 90B ) formula 1
wherein t 2A is a time required until the torque of the first composition starts increasing from the minimum torque, t 90A is a time required until the torque of the first composition reaches 90% of the maximum torque, t 2B is a time required until the torque of the second composition starts increasing from the minimum torque, and t 90B is a time required until the torque of the second composition reaches 90% of the maximum torque, when a crosslinking test is carried out by a Rubber Processing Analyzer (RPA).
2. The process for producing a laminate according to claim 1 , wherein the first composition and the second composition contain a common crosslinking aid.
3. The process for producing a laminate according to claim 2 , wherein the absolute value of the crosslinking rate difference is at most 0.05.
4. The process for producing a laminate according to claim 1 , wherein the first composition and the second composition do not contain a common crosslinking aid, and the absolute value of the crosslinking rate difference is at most 0.02.
5. The process for producing a laminate according to claim 4 , wherein the absolute value of the crosslinking rate difference is at most 0.01.
6. The process for producing a laminate according to claim 1 , wherein the absolute value of the difference between t 2A and t 2B is from 0 to 1.0 [min].
7. The process for producing a laminate according to claim 1 , wherein the absolute value of the difference between the SP value of the fluorinated elastic polymer contained in the first composition and the SP value of the non-fluorinated elastic polymer contained in the second composition, as calculated in accordance with the following formula 2, is from 0 to 3.0 [cal/cm 3 ] 1/2 :
SP value=(Δ E/V ) 1/2 formula 2
wherein V is the molar volume of the solvent, and ΔE is the cohesive energy (energy of latent heat of vaporization).
8. The process for producing a laminate according to claim 1 , wherein the degree of crosslinking of the first composition is from 5 to 150, and the degree of crosslinking of the second composition is from 5 to 300, as calculated in accordance with the following formula 3:
degree of crosslinking= MH−ML formula 3
wherein MH is the maximum torque, and ML is the minimum torque, when a crosslinking test is carried out by a Rubber Processing Analzyer (RPA).
9. The process for producing a laminate according to claim 1 , wherein the Mooney viscosity of the fluorinated elastic polymer contained in the first composition is from 10 to 300, and the Mooney viscosity of the non-fluorinated elastic polymer contained in the second composition is from 5 to 120.
10. The process for producing a laminate according to claim 1 , wherein at least one of the first composition and the second composition contains an antioxidant.
11. The process for producing a laminate according to claim 1 , wherein the crosslinking agent in the first composition and the crosslinking agent in the second composition are both organic peroxides.
12. A laminate comprising a first layer formed of a crosslinked product of a first composition containing a fluorinated elastic polymer comprising a copolymer having units based on tetrafluoroethylene and units based on propylene or a copolymer having units based on tetrafluoroethylene and units based on a perfluoro(alkyl vinyl ether), a crosslinking agent and a crosslinking aid, and a second layer formed of a crosslinked product of a second composition containing a non-fluorinated elastic polymer and a crosslinking agent and optionally a crosslinking aid,
wherein the first layer or the second layer undergoes material failure when T-peel test as specified in HS K6854-3:1999 is carried out at a temperature of from 100 to 200° C.
13. A laminated rubber hose, produced by using a laminate produced by the process for producing a laminate as defined in claim 1 .
14. A laminated rubber roll, produced by using a laminate produced by the process for producing a laminate as defined in claim 1 .