JPS60125692A - Thermal recording sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal recording sheet which can be well cut off by a cutter and enables small-size cutter to be used for long periods of time by a method in which the tear strength of thermal recording sheet is regulated to a specific value by adjusting the basic weight and/or ash amount of the sheet. CONSTITUTION:To improve the cutting property of a thermal recording sheet by a cutter, the transverse tear strength of the sheet, as specified by JISp-8116, is regulated to 45g or less and/or the longitudinal tear strength is regulated to 40g or less. For this reason, the basic weight of the sheet should be controlled to 45.0-65.0g/m<2> and the ash amount should be controlled to 5-18%.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat-sensitive recording sheet for use in facsimiles, printers, etc., and more specifically, to a heat-sensitive recording sheet with improved sharpness of cutters such as autocut.

Conventional heat-sensitive recording sheets generally develop color through a thermal reaction between a colorless or light-colored color-forming substance such as crystal violet lactone and a phenolic compound. Heat-sensitive recording paper is obtained by uniformly dispersing the wax, coating it on a support, and drying it, but the recording layer also contains various waxes to improve coloring properties, pressure coloring properties, slipperiness, etc. particle,
Wax emulsions, fatty acid metal salts, fatty acid amides, etc. are often contained, and white pigments such as clay, Merck, and titanium oxide are often contained in order to improve the whiteness and writability of the surface of the recording medium.

Recently, recording has become faster and more compact, and the number of systems that automatically cut rolled thermal paper recording notebooks into A4 size, B4 size, etc. and arrange them in a tray is increasing. Furthermore, in order to reduce power consumption and cost, attempts were made to miniaturize the auto cutter and cut thermal recording sheets with less power, and the sharpness of the cutter for thermal recording sheets became an issue. There is.

OBJECTS OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording sheet that can be used for a long period of time with a small-sized cutter that uses less electric power.

Structure of the Invention The present inventor has developed a method for achieving the above-mentioned purpose by regulating the tear strength of a heat-sensitive recording material as a characteristic for improving the sharpness of a cutter without changing the basis weight of a normal heat-sensitive recording material or the formulation of a heat-sensitive layer. We have discovered what can be achieved and completed the present invention.

That is, the heat-sensitive recording sheet of the present invention conforms to JISP-811.
The cutter is characterized by having a tear strength in the horizontal direction of 451 weights (2f) or less and/or a tear strength in the longitudinal direction of 407 f or less as defined in 6, and the cutter is sharp and can withstand long-term use. be. Lateral tear strength is 4
If the tear strength in the longitudinal direction exceeds 5ff and/or the tear strength in the longitudinal direction is 4.
When the cutter exceeds otf, the cutter becomes sharper rapidly.

Cutters such as Fakun S IJ are usually of the type equipped with a rotating blade and a fixed blade, but the heat-sensitive recording notebook of the present invention guarantees good sharpness regardless of the type of cutter.

Here, the tear strength can be easily brought to the specified value by reducing the basis weight. From the viewpoint of characteristics as a thermal recording sort and running characteristics, the basis weight is preferably 45 V/- or more, and if the basis weight becomes too high, it will be difficult to cut, so the upper limit is 65 V/-.
9/rr? It is preferable to keep it within the range. It is necessary to increase the ash content in order to keep the tear strength of the tip below the specified value.

However, if the content is too high, although the initial cutting characteristics are good, the cutter blade will wear out after being used many times, and the blade will lose its durability and become unusable soon.

Furthermore, if the ash content is too low, the tear strength will increase and cutting errors will occur even with the initial blade, which is undesirable, so the ash content is preferably 5 to 18%.

The heat-sensitive recording sheet of the present invention will be explained below with reference to Examples and Comparative Examples.

First, a liquid preparation example for a coating liquid for heat-sensitive recording sheets will be shown.

A? ffl: 3-N methylcyclohexylamino-6mether-7-anilinofluorane (PSD-150, manufactured by Shin-Nichido Kako Co., Ltd.) 150 r 5% polyvinyl alcohol (PVA) water bath solution 150 ml was mixed with 2002 ml of water and placed in a ball mill. The liquid was ground and mixed for 24 hours.

B liquid: Bisphenol A 150 f 5% PVA water bath liquid 150 Wednesday 2001 The liquid was mixed and ground and mixed in a ball mill for 24 hours.

Liquid C Nistearic acid amide 15025% PVA water bath liquid 1501 Water 2001 was mixed, and the mixture was ground and mixed in a ball mill for 24 hours.

D liquid: Calcium carbonate 150 weight 5% PVA water bath liquid 150 Water 200f The liquid was mixed and ground and mixed in a ball mill for 24 hours.

Example 1 LBKP (hardwood bleached kraft pulp) was manufactured by F Suisan (C
, S, F,) was beaten to 480 cc, 12% calcium carbonate was added, and paper was made using a Fourdrinier paper machine to give a basis weight of 52 Y/rr.
? The original paper was obtained.

Next, the above-mentioned A liquid 15 r, B liquid 502 g, C liquid 55 g and D liquid 50 S' were mixed, and 5% PVA was added to 2002 g.
In addition, it is a heat-sensitive coating liquid, and the coating amount after drying is 6f/rr? It was applied with an air knife coater so that

Example 2 LBKP produced by Tosuisan (C, S, F, ) 420 cc
Beat it, add 8% talc and make paper using a Fourdrinier paper machine to make paper with a basis weight of 5.
5t/rr? The original paper was obtained. Next, the same heat-sensitive coating liquid as in Example 1 was applied using a knife coater so that the coating amount after drying was 51/cm.

Example 3 Pulp mixed with 90% LBKP and 10% NBKP was beaten to 520 cc (C, S, F,) from Tomizu, 5% calcium carbonate was added, and paper was made using a fourdrinier paper machine to give a basis weight of 501 cc.
fA? The original paper was obtained. Next, add 10 parts of the above liquid A, B, and C.
50j' of liquid each, 6Of of liquid D! additional 5%
200 PVA? In addition, a heat-sensitive coating liquid was prepared and applied using an air knife coater so that the coating amount after drying was 5.5 r/m''ζ.

Comparative Example I 80% of LBKP and 20% of NBKP were mixed, beaten to 500 cc of P Suisan (C, S, F,), and 2% of Merck.
% was added using a Fourdrinier paper machine to obtain a base paper with a basis weight of 55 r/m''.

The same heat-sensitive coating liquid as in Example 1 was applied to this.

Comparative Example 2 LBKP was beaten to 550 cc of p-suisan (C, S, F,) and made into paper using a Fourdrinier paper machine to obtain a base paper with a basis weight of 6 (1/lt?). The same heat-sensitive coating fluid was applied.

The thermosensitive recording notebooks obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were measured for basis weight, ash content, tear strength in the transverse and longitudinal directions, and cutting errors made by an actual cutter.

These results are shown in Table 1 below. In addition, for the cutter test, tear strength (transverse and longitudinal directions) and 1
000 cuts ζ The relationship between the number of cutting mistakes @
1 and 2 are shown.

Table 1 (1) Measured according to JISP-8124.

(2) Measured according to JISP-8128.

(3) Measured according to JISP-8116.

(4) Using a Fuji Xerox 5rc23o machine with a new cutter blade, 10 sheets of paper from each example were cut (
] 0 were cut at the same time, and the number of times the cut could not be made properly or one part remained uncut (number of cuts) was measured.

(5) After cutting the paper of Example 1 with the cutter blade 10,000 times using TC230 manufactured by Fuji Xerox, the paper of each Example was force-stripped and the number of cutting errors was measured.

Effects of the Invention The present invention improves the tear strength of thermal recording 7-t (J I 5P-8
116) in the lateral direction below 452f and/
Or, it is 40 tf or less in the longitudinal direction, and has the performance that a small cutter with low power consumption can be used for a long period of time without impairing the recording characteristics.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are graphs showing the relationship between the lateral tear strength and the tangential tear strength, respectively, and the number of cutting errors.

Claims (1)

[Scope of Claims] 1) A thermosensitive recording sheet characterized by having a tear strength in the transverse direction of 451f or less and/or a tear strength in the longitudinal direction of 401f or less as defined in JISP-8116. 2) The weight specified by JISP-8124 is 45.0
~65. Off/n? A heat-sensitive recording sheet according to claim 1. 3) Ash content specified by JISP-8128 is 5
The thermosensitive recording sort according to claim 1 or 2, which has a temperature of 18%.