The present invention relates to polyester and carbodiimide containing transparent films for solar cells, which are characterized by improved resistance to hydrolysis, and also to the solar cells comprising these films. The carbodiimides have a number-average molar mass M.sub.n of >1000 to <2000 g/mol, determined by GPC, measured in tetrahydrofuran (THF) against polystyrene as standard.

A film containing: a propenyl group-containing resin (A) including, at an end of a molecule, a constituent unit represented by the following formula (1); a radical polymerizable resin or compound (B) other than the propenyl group-containing resin (A); and a curing accelerator (C), wherein the radical polymerizable resin or compound (B) includes at least one selected from the group consisting of a maleimide group and a citraconimide group. In the formula (1), —* represents a bonding hand.

In a first aspect, a polyimide film includes a dianhydride and a diamine. The dianhydride, the diamine or both the dianhydride and the diamine include an alicyclic monomer, an aliphatic monomer or both an alicyclic monomer and an aliphatic monomer. The polyimide film has a b* of 1.25 or less and a yellowness index of 2.25 or less for a film thickness of 50 μm. The polyimide film is formed by: (a) polymerizing the dianhydride and the diamine in the presence of a first solvent to obtain a polyamic acid solution; (b) imidizing the polyamic acid solution to form a substantially imidized solution; (c) casting the substantially imidized solution to form a film; and (d) drying the film.

A porous polyimide film is provided to suppress an increase in a dielectric loss tangent even when immersed in water. In the porous polyimide film, a difference between a dielectric loss tangent T1 after being left to stand for 24 hours under an atmosphere of 25° C. and relative humidity of 50% and a dielectric loss tangent T2 after immersion in water for 24 hours under an atmosphere of 25° C. is 0.0030 or less.

The present invention aims to provide resin particles that have excellent heat resistance and that, when used as base particles of conductive particles, are applicable to mounting by thermocompression bonding at low pressure to produce a connection structure having excellent connection reliability. The present invention also aims to provide conductive particles, a conductive material, and a connection structure each including the resin particles. Provided are resin particles having a 5% weight loss temperature of 350° C. or higher, a 10% K value at 25° C. of 100 N/mm.sup.2 or more and 2,500 N/mm.sup.2 or less, and a 30% K value at 25° C. of 100 N/mm.sup.2 or more and 1,500 N/mm.sup.2 or less.

Provided is a curable resin composition having developability and resolution improved without degrading the heat resistance and the chemical resistance, furthermore, a curable resin composition that is useful as a PID material for optical uses or a material for optical sensor protective films and enables the formation of a cured product having both higher transparency and excellent heat resistance, a dry film containing the curable resin composition, a cured product thereof and a printed wiring board including the cured product. A curable resin composition containing (A) an amide-imide resin, (B) a compound having an ethylenic double bond and (C) a photopolymerization initiator, wherein the amide-imide resin (A) is a reaction product of an isocyanurate-type polyisocyanate synthesized from an isocyanate having an aliphatic structure and a tricarboxylic acid anhydride and has a number-average molecular weight of 500 to 1000.

A method of recycling a polymer structure includes converting a first polymer structure into feedstock. The first polymer structure comprises particles that are bonded to one another by chemical click bonds to form a first shape. The first polymer structure is converted into feedstock particles by breaking the click bonds. The feedstock particles are formed into a second shape, and the feedstock particles are chemically click-bonded together to form a second polymer structure having a second shape. Breaking the click bonds may include heating the particles. The structures may be formed by causing first particles having dienes to chemically bond to dienophiles of second particles.

A prepreg contains a base material containing a reinforcing fiber and a semi-cured product of a resin composition impregnated into the base material containing a reinforcing fiber. The prepreg after cured has a glass transition temperature (Tg) which is higher than or equal to 150° C. and lower than or equal to 220° C. The resin composition contains (A) a thermosetting resin and (B) at least one compound selected from a group consisting of core shell rubber and a polymer component having a weight average molecular weight of 100000 or more. An amount of the (B) component is higher than or equal to 30 parts by mass and lower than or equal to 100 parts by mass with respect to 100 parts by mass of the (A) component.

A flexible substrate, a manufacturing method thereof, and a flexible display device are provided. The method includes: step S10, forming a first aerogel layer with a cross-linked structure and a nanoporous structure on a substrate; step S20: forming an inorganic layer on the first aerogel layer; step S30, forming a second flexible substrate layer on the first aerogel layer, and allowing the second flexible substrate layer to cover the inorganic layer; and step S40, peeling the first aerogel layer, the inorganic layer, and the second flexible substrate layer from the substrate to form the flexible substrate.

Pre-impregnated composite material (prepreg) that can be cured/molded to form aerospace composite parts. The prepreg includes carbon reinforcing fibers and an uncured resin matrix. The resin matrix includes an epoxy component that is a combination of a hydrocarbon epoxy novolac resin and a trifunctional epoxy resin and optionally a tetrafunctional epoxy resin. The resin matrix includes polyethersulfone as a toughening agent and a thermoplastic particle component.