JPS5869092A - Heat sensitive recording material - Google Patents

Abstract

PURPOSE:To provide a heat sensitive recording material with an upgraded recording property depending on a thermal head or the like which is high in the color developing concentration with a lateral dip elongation below a specified value while almost eliminating the deterioration in the color developing property with the passage of time. CONSTITUTION:For example, 100pts. of LBKP is beaten at a Canada standard freeness of 350cc and made a base paper at the basic weight of 50g/m<2> with a Fourdrivier paper machine after 1pt. of rosin and 2pts. of aluminum sulfate are added thereto. Then the wire side of a wet paper passing through a press section is pressed dry on a Yankee dryer with a surface temperature of 120 deg.C down to 8% in the water content and undergoes a machine calendering to finish a base paper. A coupler, a developer, a sinsetizer, a filler and the like are applied thereon and dried to obtain the intended heat sensitive recording material which is below 3% in the lateral dip elongation with a Fenchel elongation tester according to No.27-78 in JAPAN TAPPI paper & pulp test method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording paper with improved recording characteristics using a thermal head or the like.

Thermosensitive recording paper is a paper that obtains images by utilizing physical and chemical changes in substances caused by thermal energy, and a large number of processes are being studied. As a device that utilizes the physical change of substances due to heat, there has been a so-called wax-type heat-sensitive 1-scythe sheet for a long time, and it is used for electrocardiograms and the like. Other products that utilize chemical changes caused by heat include those that utilize the fact that a specific compound becomes colored or discolored due to heat, and those that utilize the fact that two or more substances react and change color due to heat. There is.

4, which utilizes a heat-induced color reaction of two or more substances, is a combination of a ferrous salt of a higher fatty acid such as stearic acid and a polyvalent hydroxy aromatic compound (US Pat. No. 14
47471), a combination of a colorless dye such as crystal violet lactone and a phenolic compound (Tokuko Shosanj-/≠
032) etc. are known.

Since these thermosensitive recording papers do not require development, they have the advantage that recording apparatuses can be made lighter and smaller, and have rapidly come into use in recent years. On the other hand, a drawback of thermal recording paper is that its recording speed cannot be sufficiently high. This is because the recording energy is heat, so there is a limit to the response relationship of the recording element. In order to overcome this drawback, various efforts have been made to improve recording devices and recording paper.

One of them is to improve the smoothness of the surface of thermal recording paper (Special Publication Shoj Coco 01-co).

Generally, in order to improve the surface smoothness of thermal recording paper,
Surface treatment such as calendaring is carried out, thereby making the recording element
The purpose is to improve the heat transfer efficiency between thermosensitive recording papers and contribute to an increase in recording speed.

However, surface treatment alone with a super-molecular polisher or the like has the disadvantage that the color development sensitivity is insufficient and the color development property deteriorates over time.

An object of the present invention is to provide a heat-sensitive recording paper which improves the above-mentioned drawbacks.

As a result of extensive study, the present inventors have determined that Japan TAPPI
Paper pulp testing method Jf6ko7-71 (Paper and pulp technical association magazine lli7
The water immersion elongation in the lateral direction is j% or less, preferably ko, using the Fuenchel elongation 1 degree tester according to 9th year/ko month issue ttjj).
It has been found that thermal recording paper with a rating of 91 or lower, more preferably 91 or lower, has high color development sensitivity and shows almost no deterioration in color development over time.

It is not clear why the coloring sensitivity increases when the water immersion elongation is low.

However, if the water immersion elongation is high, the difference in elasticity under high temperature and low humidity becomes large, which greatly changes the surface planarity m of the heat-sensitive recording layer, making the contact with the recording element rough and reducing the sensitivity.

Japan TAPPI paper pulp test method Muco 7-
What is the water immersion elongation side method according to 71? WIWI, sample basis weight (17M
The elongation rate when immersed in water at 20°C for 70 minutes under a load of 1/≠ in 2) was measured and used as the water immersion elongation value.

Generally, heat-sensitive recording materials contain a color former and a color developer separately.
After dispersing and mixing in a 10% by weight water-soluble polymer using a means such as a ball mill or sand mill, inorganic pigments such as kaolin and calcium carbonate, and if necessary, a sensitivity improver such as stearamide, and a wax emulsion are added. /, a binder, a metal soap, an ultraviolet absorber, etc. are added and mixed, and a coating liquid is applied onto a support. In the present invention, in order to reduce the water immersion elongation of the heat-sensitive recording material, there is an approach from the support base paper and the coating liquid.

As a base paper, it is dried by pressing on a Yankee dryer,
Surface coating of hydrophobic binders such as latexes such as styrene butadiene, acrylic, vinyl acetate, vinylidene chloride, etc. is contemplated.

As a heat-sensitive coating liquid, there are hydrophobic binders such as styrene-butadiene latex, acrylic latex, etc., but it can also be achieved by making a water-soluble polymer such as polyvinyl alcohol hydrophobic.

In the present invention, it is sufficient if the water immersion elongation is 391 or less,
The method is not limited to the above.

The present invention will be explained below with reference to Examples.

Preparation of support base paper LBKPt, oe part was coated with Canadian standard F ice charcoal J j Occ
Beat it, add 1 part of rosin and 2 parts of sulfuric acid,
A fourdrinier paper machine was used to make base paper with a weighing weight of 7 m.
Press it on the Yankee dryer (c) and dry it until the moisture is t.
The original paper was obtained by applying a machine calendar.

In addition, base paper B was obtained in the same manner as in the preparation of base paper A, except that a multi-barrel dryer with a surface temperature of 100 to /JO''C was used instead of the Yankee dryer.

Sara KM paper B114fl! A base paper C was obtained by processing in the same manner except that styrene-citadiene latex was further applied as a solid content using a percoater to give J f /rn''.

Preparation of heat-sensitive recording coating liquid J-diethylamino-1-chloro-7-di-Φdiethylaminofluorane J part was dissolved in water with J-polyvinyl alcohol (saponification degree varied, degree of concentration 200) as a coloring agent.
He and his team were dispersed day and night in the mail mill.

Similarly, use 20 parts of bisphenol as a color developer! - Polyvinyl alcohol aqueous solution JOO part was dispersed in a ball mill all day and night.

Furthermore, 20 parts of stearic acid amide was added as a sensitizer!
The mixture was dispersed in a ball mill with 200 parts of an aqueous polyvinyl alcohol solution.

After mixing these dispersions, 100 parts of 10% polyvinyl alcohol and Kaorinko Of were added to prepare Blood A.

1! I! 10 polyvinyl alcohol lO in MA
At-styrene butadiene latex 30 instead of O part
Coating liquid B was obtained in the same manner except that 10% of the above was added.

How to apply heat-sensitive coating liquid Apply 7 fl/ml of solids to one side of base paper using an air knife coater.
It was coated in an amount of 1.5 m, dried in a to''c dryer, and machine calendered.

Table 2 shows the combinations of base paper and coating liquid. The coating liquid was applied to the glossy side of the Naorinky dry paper and the felt side of the other paper.

Evaluation method for thermal recording paper: Recording speed (J dots per dot), recording density (J dots/mm in the main scanning direction, 6 dots in the sub-scanning direction) 7 mm, energy of the thermal head! Solid coloring was performed using Ozu rejoule/mm''. Recording 11m was evaluated as a reflected visual am value (Macbeth RD-zip type).

The recording paper was left in an atmosphere of RH70-1 〇''C for 1 month, and then the color was developed in the same manner as above, and the liver value was measured once after a period of time.

Table 1 shows the properties of the base paper described in this specification, and Table 2 shows the properties and performance of the thermal recording paper according to the examples of the present invention.

As is clear from Table 2, the heat-sensitive recording paper with low water immersion elongation has a high recording 11 degrees and does not deteriorate in color development even after storage over time, so it can be said to be an extremely useful invention.

January/7th 1945 Commissioner of the Japan Patent Office Shima 1) Haruki Tono 1, Indication of the case 1932 Patent Application No. 14 de 03
No. 2, - Name Heat-sensitive brass material 3, Relationship with the person making the amendment List of authorized applicants Date of amendment order Showa! 1.Tokyo/February 3rd, 2019 Target of amendment @ face profile I will submit a copy of the detailed statement of the amendment (change to the content on page 111).

Claims (1)

[Claims] Japan TAPPI Paper Pulp Test Method A Core 71
A heat-sensitive adhesive material characterized by having a water immersion elongation in the transverse direction of 3- or less in a Fuenchel elongation tester by