To make the foaming sufficient, and impart a heat insulating effect which is uniform for the whole surface by a method wherein a transparent varnish layer is provided between a base material layer of which the major component is paper, and a thermoplastic resin layer which becomes a foam layer.
An expanded paper cup A is constituted of a body part 1 and a bottom part 2, and for the material constitution of the body part 1 or the bottom part 2, paper 3 is made a base material, and on the surface side, a printing layer 4 and a transparent varnish layer 5 are provided. Both front and rear surface sides of these layers are covered with thermoplastic resin layers 6, 7. When the cup A is manufactured, a laminate wherein on both front and rear surfaces of the paper 3, being the base material, on which the printing and the transparent varnish have been applied, the thermoplastic resin layers 6, 7 are laminated, is made into a blank sheet with the shape of the body part 1 of the paper cup by punching, and the body part 1 is joined to the bottom part 2, and formed into a paper cup. By heating the formed paper cup, moisture in the paper evaporates, and the steam pressure and thermal expansion of air jointly work, and on the thermoplastic resin layer 6 on the surface, an expanded structure is formed.
KUBOTA FUMIHISA
OZAWA MITSUNARI
| JPH07232774A | 1995-09-05 | |||
| JPH0550536A | 1993-03-02 | |||
| JPS58183377U | 1983-12-06 |