Extruded styrene resin foam and process for producing the same

A method for producing an extruded styrene resin foam comprising the steps of heating and melting a resin consisting essentially of a styrene resin, adding a blowing agent to the styrene resin, and extrusion-foaming the resultant through a die, wherein the extrusion-foaming is carried out in a condition where (A) a halogenated flame retardant and (B) at least one compound selected from the group consisting of phosphorus type flame retardants containing nitrogen atom in a molecule, tetrazole compounds, nitrogen-containing compounds having the following general formula 1, nitrogen-containing compounds having the following general formula 2, metal borates, and boron oxides, and further a blowing agent comprising 100 to 10% by weight of at least one of saturated hydrocarbons having 3 to 5 carbon atoms and 0 to 90% by weight of other blowing agent, based on the total amount of the blowing agent, are made coexist in the styrene resin:

• wherein R1, R2 and R3 are selected from hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an organic group represented by the formula:
• —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenylene group, or a cycloalkylene group, and X is an epoxy group, a carboxyl group, a hydroxyl group, an amino group, or a phenyl group), and a phenyl group, and may be different from each other,
• wherein R4, R5 and R6 are selected from hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an organic group represented by the formula:
• —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenylene group, or a cycloalkylene group, and X is an epoxy group, a carboxyl group, a hydroxyl group, an amino group, or a phenyl group), and a phenyl group, and may be different from each other.