Polyoxymethylene, where a ratio of a low molecular weight component having a molecular weight of 10,000 or less in a molecular weight distribution is 7.0% or less of the total, and the molecular weight distribution is obtained by measurement by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) as a standard substance.

A photochromic polyurethane laminate wherein the photochromic polyurethane layer of the laminate has been crosslinked with an isocyanate-active prepolymer using a crosslinking agent. The crosslinking agent is formulated to have at least three functional groups that are reactive with functional groups of the polyurethane or of the isocyanate-active prepolymer. A method of making the photochromic polyurethane laminate includes steps of causing the crosslinking.

A photochromic polyurethane laminate wherein the photochromic polyurethane layer of the laminate has been crosslinked with an isocyanate-active prepolymer using a crosslinking agent. The crosslinking agent is formulated to have at least three functional groups that are reactive with functional groups of the polyurethane or of the isocyanate-active prepolymer. A method of making the photochromic polyurethane laminate includes steps of causing the crosslinking.

A photochromic polyurethane laminate wherein the photochromic polyurethane layer of the laminate has been crosslinked with an isocyanate-active prepolymer using a crosslinking agent. The crosslinking agent is formulated to have at least three functional groups that are reactive with functional groups of the polyurethane or of the isocyanate-active prepolymer. A method of making the photochromic polyurethane laminate includes steps of causing the crosslinking.

Disclosed is a polyoxymethylene resin composition that includes a filler in an amount of about 5 to 30 wt %, a formaldehyde reducing agent in an amount of about 0.01 to 1 wt %, and a polyoxymethylene resin constituting the remaining balance of the polyoxymethylene resin composition, all the wt % based on the total weight of the polyoxymethylene resin composition. In particular, per 1 g of the polyoxymethylene resin may include an amount of 30 to 40 ?mol of formate at terminal ends of the polyoxymethylene resin.

Disclosed is a polyoxymethylene resin composition that includes a filler in an amount of about 5 to 30 wt %, a formaldehyde reducing agent in an amount of about 0.01 to 1 wt %, and a polyoxymethylene resin constituting the remaining balance of the polyoxymethylene resin composition, all the wt % based on the total weight of the polyoxymethylene resin composition. In particular, per 1 g of the polyoxymethylene resin may include an amount of 30 to 40 ?mol of formate at terminal ends of the polyoxymethylene resin.

Long chain branched polyoxymethylene-polydimethylsiloxane copolymers are described. The copolymers have excellent impact properties, shear thinning and slip wear properties in comparison to a polyoxymethylene polymer not containing polydimethylsiloxane groups.

The present invention provides a method for producing an oxymethylene copolymer which involves polymerizing trioxane and a comonomer cationically at a polymerization temperature of 135 C. to 300 C. in the presence of a protic acid salt having the molecular weight of 1000 or less, and at least one polymerization initiator selected from the group consisting of protic acids, protic acid anhydrides, and protic acid ester compounds having the molecular weight of 1000 or less.

The present invention provides a method for producing an oxymethylene copolymer which involves polymerizing trioxane and a comonomer cationically at a polymerization temperature of 135 C. to 300 C. in the presence of a protic acid salt having the molecular weight of 1000 or less, and at least one polymerization initiator selected from the group consisting of protic acids, protic acid anhydrides, and protic acid ester compounds having the molecular weight of 1000 or less.

The present invention provides a trioxane composition which comprises trioxane as a main component, an antioxidant, and at least one alkaline organic compound selected from the group consisting of an amine compound having an alcoholic hydroxy group in the molecule thereof, a thiocarbamate compound, and an organophosphorus compound, wherein the amount of the alkaline organic compound contained is 0.01 to 10 ppm, based on the trioxane, and wherein the trioxane composition is a liquid.