Patent ID: 8053086

Claim:
An encapsulating material for solar cell comprising an adhesive and heat resistant layer (A) and a buffering layer (B), wherein the adhesive and heat resistant layer (A) and the buffering layer (B) are laminated to form a two-layered laminate and a difference in stiffness between the adhesive and heat resistant layer (A) and the buffering layer (B) is at least 30 MPa or more, wherein the adhesive and heat resistant layer (A) comprises an olefin polymer (a) having a melting point of 75° C. or higher and a storage elastic modulus at 150° C. of 10 3 Pa or more, wherein the buffering layer (B) comprises an olefin polymer (d) having a stiffness of 100 MPa or less, which is selected from the group consisting of: (i) a resin composition (g) comprising 50 to 100 parts by weight of an amorphous α-olefin polymer (e) satisfying the following requirements (1) to (3): (1) a content of polymerization unit based on α-olefin having 3 to 20 carbon atoms is 20 mole % or more; (2) melting peak of melting based on differential scanning calorimeter is not substantially observed; (3) Mw/Mn is 5 or less; and 50 to 0 part by weight of a crystalline α-olefin polymer (f), wherein a total of both polymers (e) and (f) is 100 parts by weight, and (ii) an ethylene-unsaturated carboxylate ester copolymer containing 10 to 30% by weight of unsaturated carboxylate ester unit having a melting point (T° C.) and a content (X mole %) of unsaturated carboxylate ester unit which satisfy the following formula: −3.0 X+ 125≧ T≧− 3.0 X+ 109, wherein the adhesive and heat resistant layer (A) is for contacting with a protective material, and the buffering layer (B) is for contacting with a solar cell element.