Polyolefin photovoltaic (PV) backsheets comprise a polypropylene layer stabilized with (A) at least one hindered amine with 2,2,6,6-tetraalkylpiperdine or 2,2,6,6-tetraakylpiperazinone, either or both in combination with a triazine moiety, (B) a thioester, and, optionally, (C) at least one hindered hydroxybenzoate, and/or (D) an ortho hydroxyl triazine compound. These PV backsheets exhibit a low flame spread index of <100 without the use of FR agents, and the polypropylene layer exhibits good weatherability while providing the required long term heat aging performance necessary for PV modules.

This invention relates to a coating composition, a method for coating of a metallic substrate as well as the use of the coating in a two-component coating composition.

Provided is an optical film containing a cellulose derivative, the optical film having an in-plane retardation Ro.sub.550 within the range of 120 to 160 nm measured at a wavelength of 550 nm under an atmosphere of a temperature of 23° C. and a relative humidity of 55%, and a ratio Ro.sub.450/Ro.sub.550 within the range of 0.65 to 0.99, Ro.sub.450/Ro.sub.550 being a ratio of an in-plane retardation Ro.sub.450 measured at a wavelength of 450 nm to the in-plane retardation Ro.sub.550 measured at a wavelength of 550 nm, wherein, a substituent of a glucose skeleton in the cellulose derivative satisfies the requirements (a) and (b) which are described in the specification, and the optical film contains a compound A satisfying the following condition defined by Expression (a1) which is described in the specification.

Provided is an optical film containing a cellulose derivative, the optical film having an in-plane retardation Ro.sub.550 within the range of 120 to 160 nm measured at a wavelength of 550 nm under an atmosphere of a temperature of 23° C. and a relative humidity of 55%, and a ratio Ro.sub.450/Ro.sub.550 within the range of 0.65 to 0.99, Ro.sub.450/Ro.sub.550 being a ratio of an in-plane retardation Ro.sub.450 measured at a wavelength of 450 nm to the in-plane retardation Ro.sub.550 measured at a wavelength of 550 nm, wherein, a substituent of a glucose skeleton in the cellulose derivative satisfies the requirements (a) and (b) which are described in the specification, and the optical film contains a compound A satisfying the following condition defined by Expression (a1) which is described in the specification.

Provided is an optical film containing a cellulose derivative, the optical film having an in-plane retardation Ro.sub.550 within the range of 120 to 160 nm measured at a wavelength of 550 nm under an atmosphere of a temperature of 23° C. and a relative humidity of 55%, and a ratio Ro.sub.450/Ro.sub.550 within the range of 0.65 to 0.99, Ro.sub.450/Ro.sub.550 being a ratio of an in-plane retardation Ro.sub.450 measured at a wavelength of 450 nm to the in-plane retardation Ro.sub.550 measured at a wavelength of 550 nm, wherein, a substituent of a glucose skeleton in the cellulose derivative satisfies the requirements (a) and (b) which are described in the specification, and the optical film contains a compound A satisfying the following condition defined by Expression (a1) which is described in the specification.

A polymer comprising repeat units of formula (I) and one or more co-repeat units: ##STR00001## Ar.sup.1 in each occurrence independently represent an aryl or heteroaryl group; R.sup.1 and R.sup.2 in each occurrence independently represent a substituent; p independently in each occurrence is 0 or a positive integer; Sp represents a spacer group comprising at least one carbon or silicon atom spacing the two groups Ar.sup.1 apart; and each group Ar.sup.1 is bound to an aromatic group of a co-repeat unit. The polymer may form a charge-transporting layer of an OLED or may be a host material used with a luminescent dopant in a light-emitting layer of an OLED.

A polymer comprising repeat units of formula (I) and one or more co-repeat units: ##STR00001## Ar.sup.1 in each occurrence independently represent an aryl or heteroaryl group; R.sup.1 and R.sup.2 in each occurrence independently represent a substituent; p independently in each occurrence is 0 or a positive integer; Sp represents a spacer group comprising at least one carbon or silicon atom spacing the two groups Ar.sup.1 apart; and each group Ar.sup.1 is bound to an aromatic group of a co-repeat unit. The polymer may form a charge-transporting layer of an OLED or may be a host material used with a luminescent dopant in a light-emitting layer of an OLED.

A polymer comprising repeat units of formula (I) and one or more co-repeat units: ##STR00001## Ar.sup.1 in each occurrence independently represent an aryl or heteroaryl group; R.sup.1 and R.sup.2 in each occurrence independently represent a substituent; p independently in each occurrence is 0 or a positive integer; Sp represents a spacer group comprising at least one carbon or silicon atom spacing the two groups Ar.sup.1 apart; and each group Ar.sup.1 is bound to an aromatic group of a co-repeat unit. The polymer may form a charge-transporting layer of an OLED or may be a host material used with a luminescent dopant in a light-emitting layer of an OLED.

Provided are a encapsulant composition that is for solar cells and can reduce the time required for a lamination process and improve light stability and resistance to moisture and heat, and a solar cell encapsulant layer and a solar cell module, each produced with the composition, wherein the composition includes an ethylenic copolymer and an organic peroxide having a peroxyester structure represented by formula (1) or (2)

##STR00001##

wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 each independently represent an optionally substituted alkyl group of 1 to 18 carbon atoms or an optionally substituted aryl group of 5 to 18 carbon atoms.

Provided are a encapsulant composition that is for solar cells and can reduce the time required for a lamination process and improve light stability and resistance to moisture and heat, and a solar cell encapsulant layer and a solar cell module, each produced with the composition, wherein the composition includes an ethylenic copolymer and an organic peroxide having a peroxyester structure represented by formula (1) or (2)

##STR00001##

wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 each independently represent an optionally substituted alkyl group of 1 to 18 carbon atoms or an optionally substituted aryl group of 5 to 18 carbon atoms.