US 5,328,749 AGranted

Resin-coated paper

AssigneeMitsubishi Paper Mills Limited

InventorsTouru Noda, Hiroshi Matsuda

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Abstract

This invention provides polypropylene-based resin-coated paper using paper as substrate and having excellent smoothness, especially the one which, when used for printing or heat transfer recording, keeps free from formation of white dots and occurrence of density unevenness in images, and thus is suited for printing use or heat transfer recording use. At least one side of the paper substrate is coated with a resin. The paper used as substrate is characterized by the fact that the unevenness in film thickness in machine direction (unevenness index) as measured by a film thickness meter is less than a specified value. The resin used for coating is a compounded resin composition comprising a polyethylene-based resin and a random polypropylene-based resin obtained by randomly copolymerizing principally ethylene and propylene, with the ethylene proportion being in a specified range, wherein the ratio by weight of the polyethylene-based resin to the random polypropylene-based resin is in a specified range, and the composition has been subjected to at least one round of kneading.

Claims24

Dependent claims

A resin-coated paper using as substrate a base paper comprising natural pulp, one side of said base paper being coated with a resin A, wherein said base paper has unevenness in thickness in machine direction (unevenness index) Rpy as specified below of not more than 140 mV, said resin A comprises a polyethylene-based resin and a random polypropylene-based resin which is obtained by randomly copolymerizing ethylene and propylene and has an ethylene content of 1 to 10 mol %, the ratio by weight of said polyethylene-based resin to said random polypropylene-based resin is in the range of 1:99-30:70, and said composition has been subjected to at least one round of kneading:

unevenness index Rpy:
a value (unit:
mV) determined in the following way:
A sample is let run between a pair of spherical tracers, and by using a film thickness meter which measures the variation of thickness of the sample as an electrical signal through an electrical micrometer, the variation of thickness of the sample in the machine direction is measured by scanning the sample in the machine direction at a constant rate of 1.5 m/min, under the condition that the sensitivity range of the electrical micrometer is .+-.15 .mu.m/.+-.3V, and the hanning window and FFT is applied to the electrical signal to obtain the power spectrum (unit:
mV.sup.2) by FFT analyzer, and the obtained power value is integrated from 2 to 25 Hz, multiplied by 2/3 and then raised to the one-half power.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/008,183Filed 25 Jan 1993
Priority: JP 4-01190727 Jan 1992
Granted: 12 Jul 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

B41M 5/52
Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording:…
D21H 19/20
Applied in a form other than the aqueous solution defined in group D21H19/12: comprising macromolecular compounds obtained by reactions only…
D21H 19/22
Comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds: polyalkenes, e.g. polystyrene
D21H 19/385
Characterised by the pigments: oxides, hydroxides or carbonates