Process for the production of filler-containing strips of polyester moulding masses

An unsaturated polyester or a solution thereof in a copolymerizable monomer is pasted with at least one filler with the addition of MgO and a hardener before or during the pasting and the paste is moulded either by rollers or extrusion to form a strip which may thereafter be hardened by heating. The hardener may be benzoyl, dicumyl, cumyl butyl, lauroyl or methyl ethyl ketone peroxide or t-butyl perbenzoate. An inhibitor, e.g. p-benzoquinone, 2,5-di-t-butyl quinone, hydroquinone, t-butyl, 3-methyl or 4-ethyl pyro-catechol, or copper naphthenate, and an accelerator, e.g. a cobalt soap or tertiary aromatic amine, may also be added, as can a plasticizer, e.g. phenyl or cresyl alkyl sulphonic acid esters, dioctyl phthalate or chlorinated diphenyls. The fillers may be quartz powder, barite, talc, chalk, dolomite, kaolin, or glass or asbestos fibres. A pigment such as TiO2, or an iron oxide, and a lubricant, e.g. zinc stearate, can be added. The strips produced are used to form panels. In the examples (1) a polyester derived from maleic anhydride, adipic acid, glycol and diglycol is mixed with t-butyl perbenzoate in dimethyl phthalate, asbestos fibres, quartz, barite, TiO2, talc, Zn stearate and MgO; (2) the polyester of (1) is stabilized with hydroquinone and dissolved in styrene prior to mixing with benzoyl peroxide and the fillers of (1); (4), as (2), except that a phenyl cresyl alkyl sulphonic acid ester is also added; (5) a polyester derived from maleic anhydride, phthalic anhydride and butane-1,3-diol is stabilized with hydroquinone, dissolved in styrene and mixed with benzoyl peroxide and the fillers of (1).