JP3252034B2 - Reversible thermosensitive recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording material capable of repeatedly displaying and erasing a visible image.

[0002]

2. Description of the Related Art As a reversible thermosensitive recording material, a material in which an organic low-molecular compound is mixed and dispersed in a polymer resin base material has been proposed (JP-A-55-154198). This material has the property of becoming transparent when cooled to a normal temperature from a specific temperature range T ₁ and becoming cloudy when cooled to a normal temperature from a temperature range T ₂ higher than T _1. Can be reversibly printed and erased.

[0003]

However, this material The object of the invention is to solve the above-high since the range of the temperature range T ₁ showing the transmittance or very narrow or not high transparency, very difficult to control the temperature for the printing and erasing There was a problem that.
Further, since the temperature range T ₁ showing high transmittance is low,
There is a problem that the recording material is easily changed at a low temperature and the storage stability of the recording is poor.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and comprises, as an organic low-molecular compound dispersed in a polymer resin matrix, A) a higher fatty acid hydrazide having 8 or more carbon atoms. It is characterized in that at least one kind is used in combination with at least one kind of B) an aliphatic saturated dicarboxylic acid having 12 or more carbon atoms.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an example of a card using the recording material of the present invention.

The polymer resin base material in the present invention includes:
Any resin may be used as long as it is transparent and has good film-forming properties, such as polyvinyl chloride; vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, and vinyl chloride-vinyl acetate-alcohol copolymer. Vinyl chloride copolymer; polyvinylidene chloride, vinylidene chloride copolymer, polyester, polyamide, polystyrene, polymethyl (meth)
Acrylate or a copolymer thereof is preferred.

The low-molecular organic compounds dispersed in the polymer resin matrix include at least one of A) a higher fatty acid hydrazide having 8 or more carbon atoms and B) an aliphatic saturated dicarboxylic acid having 12 or more carbon atoms. And are used together. These organic low molecular compound can vary the temperature range T ₁ of clearing by changing the mixing ratio freely, printing, setting performance and mixing ratio thinking like film forming property of the recording material of the eraser I do. In particular, since a higher melting point than the compound A component which has been conventionally used, the temperature range T ₁ showing a high transmittance and high temperature, recording material storage of recording is excellent is obtained.

The higher fatty acid hydrazide of the component A includes:
Caprylic acid, pelargonic acid, capric acid, lauric acid,
Hydrazides such as myristic acid, palmitic acid, stearic acid, behenic acid, lignoceric acid and cerotic acid are exemplified, and hydrazides of higher fatty acids having 16 or more carbon atoms are particularly preferable.

The B-component aliphatic saturated dicarboxylic acids having 12 or more carbon atoms include dodecandioic acid, tridecandioic acid, tetradecandiodic acid, pentadecandiodic acid, hexadecandiodic acid, octadecandioic acid, nonadecandioic acid, eicosanediacid. Acids, heneicosantioic acid, docosantioic acid, tricosandioic acid, tetrachosantioic acid, hexacosantioic acid, triacontanedioic acid, tetratriacontanedioic acid, and the like.

[0010] The weight ratio of the A component and B component, without the effect of expanding the range of temperature range T ₁ in a proportion of component B is less than 2%, also formed between the recording material layer proportion of component B exceeds 70% The film becomes difficult. The preferred weight ratio is from balance temperature range and the deposition of the temperature range T _1, A: B at 90: 10-50: 5
It is in the range of 0.

The total amount of the component A and the component B is
10 to 80 parts by weight, preferably 30 to 6 parts by weight per 0 parts by weight
The range is 0 parts by weight. In the present invention, if necessary,
In addition to the above components, for example, JP-A-55-154198
Other low-molecular-weight organic compounds described in JP-A No. 5-2350 may be further used in combination.

When this recording material is heated at a temperature T ₁ by a heating means such as a thermal head, a heating stamp, a heating roll, or the like, the recording material becomes transparent. Next, this transparent recording materials, thermal head, do it like in and locally heated to a higher temperature T ₂ than T ₁ heating stamp, only the heated portion is opacified (cloudy), displaying a visible image can do. To erase the image, it may be heated to a temperature range T ₁ again.

The width of the transparent temperature range T ₁ is 5 ° C.
Stable transparent state is hardly obtained because of the difficulty to control the temperature of the heating means such as a thermal head is less than, also when he 60 ° C. or higher, excessively high temperature T ₂ to be printed, the thermal recording materials due to repeated printing and erasing Deterioration easily proceeds, but according to the present invention, a temperature range of, for example, about 20 to 30 ° C. can be easily obtained.

FIG. 1 shows a card which is an example of the use of the recording material of the present invention. The recording material layer is composed of a synthetic resin base sheet 1 such as polyethylene terephthalate (PET). 3, a protective layer 4, and a printed layer 5 for forming a visible recording display window 6 are laminated. A magnetic recording layer 7 and a protective layer 8 are provided on the back surface.

The reflection layer 2 is for making the image formed on the recording material layer 3 easy to see, and is preferably a deposited layer or foil of aluminum, tin or the like, or a paint layer mixed with metal powder.

The protective layer 4 is for preventing thermal deterioration of the recording material layer 3, and is made of PET, polyetherimide, polyetheretherketone, polysulfone, polyphenylenesulfide, polyarylate, polyethersulfone, polycarbonate, polyethylenena. Phthalate,
A film or coating of a transparent resin having high heat resistance such as polyimide or acrylic resin can be used.

This card can be used, for example, as a prepaid card for admission, shopping, rental, etc.
By displaying the amount of money used and the balance on the recording material layer 3 together with the magnetic recording at each use, an accurate balance can always be known.

[0018]

【Example】

(Example) Aluminum was vapor-deposited as a reflective layer on the surface of a 188-μm-thick PET sheet in which a magnetic recording layer was previously formed to a thickness of 10 μm on the back surface. On top of this, a recording material consisting of polymethyl methacrylate resin: 100 parts by weight Palmitohydrazide: 32 parts by weight (C ₁₅ H ₃₁ CONHNH ₂ melting point: 111 ° C.) 1,12-tetradecandioic acid: 16 parts by weight is dissolved in tetrahydrofuran. And dried to form a recording material layer having a thickness of 10 μm.

On top of that, a PE having a thickness of 2 μm is formed as a protective layer.
A T-film was attached, and printing was performed to form a visible recording display window. On the other hand, a protective layer was provided on the magnetic recording layer on the back surface, and punched into a card shape.

The recording material layer of this card became transparent when cooled from 105 ° C. to room temperature, and became opaque when cooled from 130 ° C. to room temperature.

(Comparative Example) A card was prepared in the same manner as in the Example except that polymethyl methacrylate resin: 100 parts by weight behenic acid (melting point: 80 ° C.): 32 parts by weight was used as a recording material.

Then, each of the obtained cards is heated from 50 ° C. to 1
The recording material was heated to 30 ° C. at 1 ° C. intervals, and the reflection density of the recording material at each temperature was measured with a Macbeth reflection densitometer RD-914.

The measured value is an opaque state 0.5 or less, also called for clearing temperature range T ₁ and its temperature range above 1.0 as a transparent state. Further, the maximum reflection density when transparent and the minimum reflection density when opaque were determined. Table 1 shows the results.

[0024]

[Table 1]

It can be seen that the recording material of the present invention has a wide temperature range of the clearing temperature T ₁ , and a stable transparent state can be obtained even if the heating temperature fluctuates somewhat. The transparent temperature range T ₁ is to high temperature, improves the storage stability of the recording to the environment temperature.

[0026]

The present invention recording material according to the present invention has a wide transparent temperature range, therefore the heating temperature is varied stable transparent state is obtained are also preservability of clearing temperature range T ₁ is recorded to high temperature It is an excellent recording material and suitable for displaying a visible image that can be repeatedly printed and erased on a prepaid card or the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a card using the recording material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Card base material 2 Reflective layer 3 Recording material layer 4 Protective layer

Claims (1)

(57) [Claims] 1. A reversible thermosensitive recording material comprising a polymer resin matrix in which an organic low-molecular compound is dispersed and which reversibly changes between a transparent state and an opaque state depending on temperature, wherein A) A reversible thermosensitive recording material comprising a combination of at least one hydrazide of higher fatty acid having 8 or more carbon atoms and at least one of B) an aliphatic saturated dicarboxylic acid having 12 or more carbon atoms.