Transparent paper or cardboard substrate and method for its production
OwnerPeter RÄTTÖinventor
Life of this patent
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Abstract
Method of printing at least one transparent area on a major surface of a non-coated paper or cardboard substrate (1), wherein an optical transmittance, as measured with spectrophotometry, through the substrate (1) at a printed transparent area (2) is at least 20% higher than through the substrate (1) at a non-printed area (3) of the same paper or cardboard 5 substrate (1) at a wavelength in the electromagnetic spectrum of wavelengths from 400 nm to 1000 nm that.
Claims9
A method of printing at least one transparent area on a major surface of a non-coated paper or cardboard substrate, wherein an optical transmittance, as measured with spectrophotometry, through the substrate at a printed transparent area is at least 20% higher than through the substrate at a non-printed area of the same paper or cardboard substrate at a wavelength in the electromagnetic spectrum of wavelengths from 400 nm to 1000 nm, the method comprising:
- (1) contacting at least one area of a major surface of the non-coated paper or cardboard substrate with a polymerizing and drying or semi-drying oil composition using a printing press, wherein the oil in the oil composition has a diffractive index of 1.4 to 1.6, and the at least one area ranges in size from 100 μm2 to an entire area of the major surface of the substrate,
- (2) allowing the oil composition to penetrate through the thickness of the substrate, and
- (3) drying the at least one printed area, forming at least one printed transparent area on the substrate, whereby any content in a packaging or envelope formed by the substrate is visible from outside of the substrate through the at least one printed transparent area.
Dependencies are inferred from the claim text.