| 摘要 |
<p>A matrix is made by applying a thin film of moulding material to the record, attaching a support, and pulling the matrix away when the moulding material has hardened. A copy record is made by applying a thin film of impression material to the matrix, attaching a support, and pulling the copy away when it has hardened. The moulding material for the matrix is pref. a silicone resin, a silicone rubber, or polyurethane. The impression material for the copy is pref. a synthetic resin, partic. epoxy resin, or an organic poly -sulphide. The support for the copy is pref. a stuck-on foil of plastic (partic. polyester), or cardboard; for the matrix the same, plus polystyrene.</p> |
