| 摘要 |
A laminated structure forming a synthetic paper made of a base or backing film layer made of a thermoplastic resin in a biaxially oriented state. A paper-like film layer is laminated to the base film layer and comprises a thermoplastic resin having 0.5 to 65% by weight of particles of a fine, inorganic filler dispersed in the resin thereof substantially uniformly. The paper-like film layer is in an uniaxially oriented state and has microvoids dispersed therein formed by stretching the laminated films in a heated state. The microvoids comprise microvoids open to a surface of the paper-like film layer free of the base film layer and include microvoids, open and closed, distributed in the paper-like film layer defining therein a cellular, fibrous structure. The two films are formed from thermoplastic resinous compositions in which the components of each composition are well admixed and particles of a fine filler are uniformly distributed in the thermoplastic resin of the paper-like film layer to obtain, as much as possible, microvoids distributed therein uniformly. After the base film layer is formed, it is stretched in a heated state in a machine for longitudinal direction to orient the film uniaxially. The paper-like layer is laminated under pressure on one surface of the base film layer while in a melted state and the resulting laminated structure is stretched transversely to at least 2.5 times the original transverse dimension of the portion of film being stretched between grippers of a stretching machine. This orients the base film layer biaxially and the paper-like film layer uniaxially. The stretching must be sufficient for the stretching and particles of filler to develop microvoids in the paper-like film layer rendering it a cellular and fibrous structure.
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