Improvements in and relating to synthetic resin sheets and matrices made therefrom

Abstract

Abstract 505,579. Moulding synthetic resins. BAKELITE, Ltd. Nov. 12, 1937, No. 31160. Convention date, Nov. 24, 1936. [Class 87 (ii)] [Also in Groups VIII and XVI) A sheet suitable for making matrices, for sound records comprises a base composed of a heat-hardenable synthetic resin and a filler, consisting partly of long matting fibres and partly of short matting fibres and a surface layer of moulding material composed of a heathardenable synthetic resin and a filler, e.g. wood flour. Suitable synthetic resins include phenol-formaldehyde, urea-formaldehyde, aniline-formaldehyde and alkyd resins. They may be replaced in part by natural resins such as rosin or gum accroides, or by fusible or slowly hardening synthetic resins such as novolaks or oit-soluble phenol-formaldehyde rosins. Suitable bases are described in Specification 505,578, [Group IV]. They may contain, if desired, dyes, pigments and fillers such as clay, talc or silica. The surface layer may be applied by brushing or spraying in the form of a suspension in water or an organic liquid such as alcohol or toluene or in a mixture of the two. Matrices are moulded at a temperature of 275-300‹ F. and at a pressure of 100 to 500 lb. per square inch. The sheet material may also be used in making plaques and embossed signs.

Inventors

No inventors recorded.

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