a back - face protection sheet for a solar cell module exhibits excellent adhesion strength and tensile strength even under a high - temperature and high - humidity environment , by using a plastic film that has excellent characteristics such as electrical insulation characteristic , heat resistance , dimension stability , mechanical strength , weatherability , and water resistance , and using a two - part type lamination adhesive having excellent weatherability . the back - face protection sheet is made to have excellent adhesion strength and tensile strength for a long period of time , even under a high - temperature and high - humidity environment , by improving weatherability as base material films , and giving weatherability to the two - part type lamination adhesive to be used in pasting together the base material films .