Support sheet for photographic printing sheet
AssigneeOji Paper Co., Ltd.
InventorsMasahiro Kamiya, Tsunehisa Shigetani
Life of this patent
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Abstract
A support sheet for a photographic printing sheet, having a high resistance to scratching, curling and a enhanced ability to be sharply cut, and provided with front and back surface coating layers formed respectively on the front and back surfaces of a substrate sheet and comprising, as a main component, a polyolefin resin; the polyolefin resin in the front surface coating layer comprising 30 to 70% by weight of a linear low density ethylene-propylene or butene-1 copolymer (L-LDPE) having a density of 0.915-0.935 g/cm.sup.3 and a melt index of 15-30 g/10 min and 30 to 70% by weight of a high pressure-processed low density polyethylene (HP-LDPE) having a density of 0.915-0.928 g/cm.sup.3 and a melt index of 1 to 5 g/10 min.
Claims5
A support sheet for a photographic printing sheet comprising:
- a substrate sheet, and
- front and back surface coating layers formed respectively on front and back surfaces of the substrate sheet and composed of a resinous material comprising, as a principal component, a polyolefin resin;
- said polyolefin resin in the front surface coating layer comprising a mixture of 30 to 70% by weight of at least one linear low density polyethylene copolymer (L-LDPE) of ethylene with 1 to 10% molar % of at least one .alpha.-olefin selected from the group consisting of propylene and butene-1 and having a density of from 0.915 to 0.935 g/cm.sup.3 and a melt index of 15 to 30 g/10 minutes;
- and 30 to 70% by weight of at least one high pressure-processed low density polyethylene (HP-LDPE) having a density of from 0.915 to 0.928 g/cm.sup.3 and a melt index of from 1 to 5 g/10 minutes;
- and said polyolefin resin in the back surface coating layer having a higher density than that of the polyolefin resin in the front surface coating layer.
Dependencies are inferred from the claim text.