JP2000084475A - Multilayered coated sheet and method for detecting coating quantity and coating irregularity thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered coated sheet easily detectable in the coating quantities and coating irregularities of its respective coating layers and a method for detecting the coating quantities and coating irregularities of the respective layers of the multilayered coated sheet. SOLUTION: In a multilayered coated sheet wherein two or more coating layers are successively provided on a base material, as one means for obtaining this multilayered coated sheet, phosphors different in fluorescent hue from each other are added to the respective coating layers. Further, the coating quantities and coating irregularities of the respective layers of the multilayered coated sheet are detected by adding phosphors different in fluorescent hue from each other to the respective coating layers of the multilayered coated sheet having two or more coating layers successively and irradiating this sheet with exciting light to obtain fluorescence quantities and fluorescence distribution and measuring coating quantities and coating irregularities form these fluorescence quantities and the fluorescence distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer coated sheet,
And a method for detecting the coating amount and coating unevenness of a multilayer coated sheet.

[0002]

2. Description of the Related Art As a method for detecting the coating amount of a coating layer of a sheet having one coating layer or coating unevenness, a phosphor is contained in the coating layer and the sheet is irradiated with excitation light. JP-A-62-132975, JP-A-63-158164, and JP-A-6-317527 describe detection of the coating amount or coating unevenness based on the amount of emitted fluorescent light. There is a need for a method of detecting the coating amount and coating unevenness of each layer of a multilayer coating sheet having two coating layers.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-layer coated sheet capable of easily detecting the coating amount and coating unevenness of each coating layer, and the coating amount of each layer of the multilayer coated sheet. And a method for detecting coating unevenness.

[0004]

Means for Solving the Problems In a multi-layer coated sheet having two or more coating layers on a substrate, as one means for obtaining the above-mentioned multi-layer coated sheet, the present invention relates to each of the coated layers. Contains phosphors having different fluorescent colors. Further, as a means for detecting the coating amount and coating unevenness of each layer of the multilayer coated sheet, the present invention provides a fluorescent color tone for each coated layer of a multilayer coated sheet having two or more coated layers. A different phosphor is contained, and the coating amount and the coating unevenness are measured from the fluorescence amount and the fluorescence distribution emitted by irradiating the sheet excitation light.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized in that each coating layer of a multi-layer coating sheet having two or more coating layers on a substrate contains phosphors having different fluorescent tones. The content of the phosphor contained in each coating layer is not particularly limited, but is about 0.01 to 10% by weight, preferably about 0.05 to 1.0% by weight based on each coating layer. is there. When the content of the phosphor exceeds 10% by weight, after the uppermost layer is formed, the excitation light is almost absorbed by the uppermost layer, and there is a possibility that the measurement of the lower coating layer and the coating unevenness cannot be performed. On the other hand, when the content is less than 0.01% by weight, the amount of fluorescence decreases, and there is a possibility that measurement of coating unevenness and coating unevenness in particular cannot be performed. The excitation light applied to the multilayer coated sheet includes, for example, X-rays, ultraviolet light, visible light, and the like.

The thickness of each coating layer is not particularly limited, but is preferably about 0.1 to 20 μm. If the thickness is less than 0.1 μm, a uniform coating surface may not be obtained. If the uppermost layer exceeds 20 μm, excitation light is almost absorbed by the uppermost layer, and measurement of coating unevenness and unevenness of the lower coating layer may not be possible. There is. The higher the transparency of each coating layer, the easier the measurement of the coating amount.

[0007] Examples of the phosphor contained in each coating layer include an organic fluorescent dye and an inorganic fluorescent pigment. Specific examples of the organic fluorescent dye include, for example, diaminostilbene (blue fluorescent light), uranine (yellow green fluorescent light), thioflavin (yellow fluorescent light), eosin (yellow orange fluorescent light), sodium fluorescein (yellow green fluorescent light), rhodamine G (red fluorescent light) Fluorescence). Examples of the inorganic fluorescent pigment include zinc sulfide, calcium sulfide, and cadmium sulfide.

For example, when the phosphor in each coating layer is excited by the same kind of excitation light (for example, ultraviolet light), the coating amount and the coating unevenness in each coating layer may be different from those to be measured. It can be measured by using a filter that cuts the fluorescence from the engineered layer. It is preferable that the lower layer contains a phosphor having a long fluorescent color tone wavelength. Alternatively, the coating amount and the coating unevenness can be detected by making each coating layer contain a phosphor having a different excitation light wavelength for emitting fluorescence.

The base sheet for forming the coating layer is not particularly limited, and examples thereof include paper, film, synthetic paper, metal, wood, ceramic and the like. The surface of the base sheet may be subjected to a corona discharge treatment or a conductive treatment.

Each coating layer is prepared by applying a coating solution for each coating layer on at least one surface of a substrate sheet, for example, by an air knife system, a Meyer bar system, a pure blade system, a rod blade system, a reverse roll system, or a microgravure. method,
It is obtained by coating by gravure method, slit die method, spray method, curtain method, and then solidifying with ionizing radiation or heat.

[0011]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples. As an example, a heat-sensitive recording body composed of a multilayer coated sheet will be exemplified. “Parts” in each of Examples and Comparative Examples indicates “parts by weight”.

Example 1 Preparation of solution A (leuco dye dispersion) 20 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, 20 parts of a 10% aqueous solution of sulfone-modified polyvinyl alcohol , And a composition consisting of 10 parts of water having an average particle diameter of 0.3 μm using an ultraviscomil.
It grind | pulverized until it became m, and obtained liquid A.

Preparation of Liquid B (Coloring Agent Dispersion) 20 parts of 4-hydroxy-4′-isopropoxydiphenylsulfone, 1 part of sulfone-modified polyvinyl alcohol
A composition comprising 20 parts of a 0% aqueous solution and 10 parts of water was pulverized using an Ultra Visco mill until the average particle diameter became 0.3 μm to obtain a liquid B.

Preparation of Coating Solution for Thermosensitive Recording Layer 50 parts of solution A, 100 parts of solution B, and a 10% aqueous solution 60 of polyvinyl alcohol (trade name: PVA117, manufactured by Kuraray Co., Ltd.)
Part, styrene-butadiene latex (trade name: L-
1537, 50% solid content, 50 parts by Asahi Kasei Kogyo)
A composition consisting of 5 parts of a 1% aqueous solution of rhodamine G having a red fluorescent color tone and 30 parts of water was mixed and stirred to obtain a coating liquid for a heat-sensitive recording layer.

Preparation of Coating Solution for Protective Layer 50 parts of a 60% dispersion (average particle size: 0.5 μm) of kaolin (trade name: UW-90, manufactured by EC), 50 parts of carboxy-modified polyvinyl alcohol (trade name: Gohsenal T-) 33
0, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
Zinc stearate dispersion (trade name: Hydrine Z-7-
30, a solid content of 31.5%, manufactured by Chukyo Yushi Co., Ltd.), 10 parts, a 1% aqueous solution of diaminostilbene having a blue fluorescent color, 5 parts, a 40% glyoxal aqueous solution, 3 parts, and 240 parts of water are mixed and stirred. Thus, a coating solution for a protective layer was obtained.

Preparation of Thermosensitive Recording Material (Multilayer Coated Sheet) A coating solution for a thermosensitive recording layer and a coating solution for a protective layer were dried on one side of a high quality paper of 92 g / m ² by a slit die coater. The application amount is 8.0 g / m ² and 2.5 g, respectively.
/ M ² to obtain a heat-sensitive recording material having a heat-sensitive recording layer and a protective layer.

Example 2 In the production of the heat-sensitive recording medium of Example 1, a transparent polyethylene terephthalate film (trade name: HMW) was used instead of high-quality paper of 92 g / m ² per square meter.
−100, thickness 100 μm, haze value 1%, manufactured by Teijin Limited)
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that

Comparative Example 1 In the preparation of the coating solution for the heat-sensitive recording layer of Example 1, 1% of rhodamine G having a red fluorescent color tone was used.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 5 parts of the aqueous solution was not added.

The method for detecting the coating amount and coating unevenness of the thus obtained thermosensitive recording medium (multilayer coated sheet) will be described below.

[Coating Amount] A black light (ultraviolet) is irradiated to various thermosensitive recording media having a thermosensitive recording layer and a protective layer of a known coating amount in advance, and the amount of red fluorescence from the thermosensitive recording layer is determined. By inputting the amount and the relationship between the amount of blue fluorescence from the protective layer and the amount of coating to a computer, the amount of coating can be measured by irradiating the above-mentioned thermosensitive recording medium with black light. When measuring the amount of red fluorescence from the heat-sensitive recording layer and the amount of coating, a filter for cutting off the blue fluorescence from the protective layer may be provided in the light receiver for measuring the amount of fluorescence. Further, when measuring the amount of blue fluorescent light from the protective layer and the amount of application, a filter for cutting red fluorescent light from the heat-sensitive recording layer may be provided in the light receiver for measuring the amount of fluorescent light.

[Coating unevenness] The heat-sensitive recording medium is irradiated with black light, and the coating unevenness of the heat-sensitive recording layer can be visually determined through a filter that cuts blue fluorescent light from the protective layer. The coating unevenness of the protective layer can be visually determined through a filter that cuts red fluorescence from the heat-sensitive recording layer.

The coating amount and coating unevenness of the heat-sensitive recording layer and the protective layer of the multilayer coated sheets of Examples 1 and 2 can be easily detected without destruction. The coating amount and coating unevenness could not be measured from the fluorescence amount.

[0023]

The present invention is a multilayer coated sheet which can easily detect the coating amount and the coating unevenness of each coating layer, and can easily reduce the coating amount and the coating unevenness of each layer of the multilayer coated sheet. This is the method of detecting.

Claims (2)

[Claims] 1. A multilayer coated sheet having two or more coating layers on a substrate, wherein each coated layer contains a phosphor having a different fluorescent color tone. 2. A multi-layer coated sheet having two or more coating layers on a base material, wherein each coating layer contains phosphors having different fluorescent tones, and the sheet is irradiated with excitation light to emit light. A method for detecting a coating amount and a coating unevenness of a multi-layer coated sheet, wherein the coating amount and the coating unevenness are measured from the fluorescent amount and the fluorescence distribution.