Abstract: Discoloration of dicarboxylic acid chlorides having 4 to 10 carbon atoms, especially those made by reacting the corresponding dicarboxylic acid with phosphorus trichloride, is inhibited by the addition of a dicarboxylic acid thereto. Addition of a dicarboxylic acid to a dicarboxylic acid chloride which has already discolored precipitates impurities and thus clarifies the dicarboxylic acid chloride. The clarified dicarboxylic acid chlorides are useful as starting materials to make polyester foam materials.

Abstract: A method of and apparatus for uniformly debossing and perforating a ribbon of thermoplastic sheet material or film through the use of vacuum in combination with a flash heating source such as a flow of hot air. The apparatus causes a ribbon of such film to be forwarded from a supply such as a roll of thermoplastic material, thence about a circumferentially extending portion of a rotating debossing-perforating cylinder, and then downstream where the debossed and perforated film may be further processed or where it may be wound on a spool to form a roll thereof. The debossing-perforating cylinder comprises a perforated tubular member through which a plurality of independently adjustable levels of vacuum can be applied from within the cylinder to circumferentially spaced sections of the film in contact with the exterior surface of the perforated tubular member. The apparatus further causes a virtual curtain of hot air to be directed radially inwardly towards a predetermined zone of the perforated tubular member.