JPH0457214A - Magnetic ink for magnetic card consisting of vinyl chloride system - Google Patents

Abstract

PURPOSE:To improve a non-curling property by using a polyurethane polyurea resin as a binder component and forming the resin as ink by a solvent essentially consisting of an alcohol solvent. CONSTITUTION:The magnetic ink for the magnetic card consisting of a vinyl chloride system consists essentially of the polyurethane polyurea resin soluble in the alcohol solvent as the binder of ferromagnetic particles. The resin obtd. by subjecting the terminal isocyanate prepolymer which is the reaction product of bifunctional polyol and the diisocyanate compd. expressed by formula I to chain extension by diamine is applied as the polyurethane polyurea resin to be used as the binder of the magnetic ink. The bifunctional polyol is preferably ethylene glycol, butanediol, 1,6-hexane diol, 3-methyl-1, 5-bentadiol, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a vinyl chloride-based magnetic ink for magnetic cards, and more specifically, a non-curling adhesive coating when applied to a polyvinyl chloride sheet serving as a card base material. The present invention relates to a magnetic ink that can form a film.

[Conventional technology]

Magnetic cards include cash cards, credit cards,
It is widely used as prepaid cards such as commuter passes, telephone cards, and orange cards. These magnetic cards have a magnetic layer on the surface of the substrate (base) such as paper or plastic film in a striped form or on the entire surface of one side, and have letters and designs printed on the other parts, and have a magnetic layer on the surface of the base, such as paper or plastic film. It is finished to a predetermined size by adding a printing layer to display visual information, embossing, etc., and uses the magnetic layer to magnetically record information as needed.

As the substrate, a sheet of polyvinyl chloride, polyethylene terephthalate (PET), paper, etc. is used, and as a magnetic ink for providing a magnetic layer on the substrate, for example, acrylic resin, polyurethane resin, polyester resin, butyral resin is used. , a synthetic resin such as vinyl chloride-vinyl acetate copolymer is used as a binder, and for example, γ-Fez
Magnetic particles such as ES, Co-coated 7-Fez0=, and other components such as surfactants, silane coupling agents, plasticizers, waxes, silicone oils, and pigments are added as necessary, and the process is carried out using a three-roll mill, a sand mill, A material prepared by kneading with a ball mill or the like is used.

[Problem to be solved by the invention]

Among the above magnetic cards, orange cards, telephone cards, ski lift tickets, etc. often use relatively thin polyvinyl chloride sheets as their bases.

However, when such a thin polyvinyl chloride sheet is used as a base and a magnetic ink using toluene/methyl ethyl ketone as a solvent is applied to it, the base polyvinyl chloride sheet is eroded by the magnetic ink solvent and over time. As a result, there is a problem of warping (curling).

For this reason, attempts have been made to use magnetic ink using an alcohol-based solvent that does not attack the polyvinyl chloride sheet, but in this case, the binder resin is a polyamide resin that is soluble in an alcohol-based solvent, or cellulose. Since it is necessary to use a limited number of specific resins such as a type resin and a butyral type resin, there is a drawback that a satisfactory performance in terms of adhesion of magnetic ink cannot be obtained.

The inventors of the present invention have conducted extensive research to solve the above-mentioned problems, and have found that when an alcohol-based solvent-soluble polyurethane polyurea resin is used as a binder for magnetic ink, it has extremely good adhesion and can be applied to printing substrates. The present invention was completed based on the finding that the warping phenomenon of polyvinyl chloride sheets can be effectively reduced.

[Means for Solving the Problems] That is, the vinyl chloride-based magnetic ink for magnetic cards provided by the present invention is based on an alcohol-based solvent-soluble polyurethane polyurea resin as a binder for ferromagnetic particles. This is a structural feature.

The present invention will be explained in detail below.

In the present invention, the polyurethane polyurea resin used as a binder for magnetic ink is obtained by chain-extending a terminal isocyanate prepolymer, which is a reaction product of a bifunctional polyol and a diisocyanate compound represented by the following general formula, with a diamine. things are applied.

As the bifunctional polyol, any conventionally known polyol can be used, and specifically, ethylene glycol, butanediol, 1,6-hexanediol, 3-methyl-1,
Polyester polyol obtained by reacting a diol such as 5-bentanediol or a mixture thereof with a dicarboxylic acid such as adipic acid, sepacic acid, phthalic acid, isophthalic acid, etc.; polytetramethylene glycol, polycaprolactone glycol, polypropylene Glycol; alkylene oxide adduct of diol, propylene oxide adduct of bisphenol A; polyester polyol and polycaprolactone copolymer polyol, valerolatone polyol; alkylene oxide adduct of monoamine, oleylamine-propylene oxide adduct, etc., or mixtures thereof, etc. can be mentioned. Such bifunctional polyols have a molecular weight of about 400 to 4.
, 000 and an OH value of about 280 to 28 is preferred in the present invention.

The diisocyanate compound to be reacted with the above bifunctional polyol is represented by the above structural formula, and is 1,3
-Bis(α,α-dimethylisocyanatemethyl)benzene (TMχDI) or tetramethylxylylene diisocyanate. This diisocyanate compound may be used alone, or other known diisocyanate compounds,
For example, it may be used in combination with isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), I-lylene diisocyanate (TDI), xylylene diisocyanate (XDI), water-added XDI, diphenylmethane diisocyanate (MDI), and the like.

A method for producing a terminal isocyanate prepolymer from a bifunctional polyol and a diisocyanate compound may be based on a known method, and can be performed in an organic solvent or without using an organic solvent at an equivalent ratio of N COlo H = 2:1.2. This is a method of reacting with Although terminal isocyanate prepolymers with various molecular weights can be obtained depending on the reaction conditions, particularly the NCO10H ratio, the preferred molecular weight of the terminal isocyanate prepolymer in the present invention is about 800 to 8,000.
, and NC0% is in the range of 10 to 1%.

As the diamine used for chain extension of the terminal isocyanate prepolymer, any conventionally known diamine can be used, and preferred specific examples include diaminobenzene, 4,4-diaminodiphenylmethane, and water-added 4,4- Examples include diaminodiphenylmethane, isophorone diamine, hexamethylene diamine, trimethylhexamethylene diamine, 1,3-bis(α,α-dimethylaminomethyl)benzene, and the like. These diamines are NCO/
NH, -0,8: It is preferable to use within the range of 1.0.

Both reactions may be carried out by adding a diamine to the terminal isocyanate prepolymer solution, preferably in an organic solvent;
The terminal isocyanate prepolymer may be added to the diamine solvent, or both may be mixed simultaneously. The reaction conditions are about 15 to 40°C and 0.5 to 2
It is best to allow time to react.

As the organic solvent used in the production of the above-mentioned terminal isocyanate prepolymer and polyurethane polyurea resin, toluene, methyl ethyl ketone, ethyl acetate, and isopropyl alcohol are used alone or in mixtures. However, alcoholic solvents should not be used during the production of the terminal isocyanate prepolymer.

The polyurethane polyurea resin obtained as described above preferably has a molecular weight of about 15,000 to 100,000, and the obtained polyurethane polyurea resin solution can be used as it is.

The binder for magnetic ink according to the present invention is mainly composed of the above-mentioned polyurethane polyurea resin, and can be used not only alone but also in combination with other resins. Examples of resins used in combination include cellulose derivatives such as nitrocellulose, cellulose acetate, and cellulose acetate butyrate, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and vinyl chloride-vinyl acetate. - Salt vinyl acetate resin such as maleic acid copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, cotton-like polyester resin, (meth)acrylic acid-acrylonitrile copolymer,
Examples include methyl (meth)acrylate-acrylonitrile copolymer, polyvinyl acetal, polyvinyl butyral, phenoxy resin, epoxy resin, and polyamide resin.

Such a binder component is used in a ratio of 10 to 50 parts by weight, preferably 15 to 30 parts by weight, per 100 parts by weight of ferromagnetic powder. As the ferromagnetic powder, γFew O
s, Fes Oa, r Few o3 and Fe50
．． γ-Fe doped with cobalt.

08, cobalt-doped Fe, O, chlorine dioxide, barium ferrite, etc.

Further, a dispersant, a lubricant, a reinforcing agent, an antistatic agent, etc. can be added to the magnetic ink of the present invention, if necessary.

As the dispersing agent, fatty acids having 12 to 18 carbon atoms such as capric acid, oleic acid, linoleic acid, alkali metal salts or alkaline earth metal salts of these fatty acids, lecithin, and the like are used.

As the lubricant, solid lubricants such as molybdenum disulfide and tungsten disulfide, silicone oil, and fatty acid esters are used. As reinforcing materials, alumina, silicon carbide,
Chromium oxide, corundum, etc. are used.

As the antistatic agent, carbon black, surfactant, etc. are used.

In order to prepare the magnetic ink of the present invention, an alcohol-based organic solvent is used, and examples of this type of solvent include alcohols such as methanol, ethanol, isopropanol, and phthanol; aromatic solvents such as toluene and xylene; Hydrocarbons, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, esters such as ethyl acetate, butyl acetate, ethylene glycol dimethyl ether,
Glycol ethers such as ethylene glycol 7-ethyl ether can be mentioned.

Since the present invention is particularly directed to a thin vinyl chloride sheet as a substrate, it is preferable to use the above-mentioned alcoholic solvent as an essential component and to use it in combination with other solvents.

A suitable mixing ratio of solvents is roughly as follows.

10 to 80 parts by weight of alcohols, 10 parts by weight of aromatic hydrocarbons
~50 parts by weight, 0-20 parts by weight of ketones, 1 part by weight of glycol ether! 0 to 10 parts by weight of esters, 0 to 10 parts by weight of esters.

(Function) The polyurethane polyurea resin constituting the binder in the present invention is soluble in alcohol-based solvents that do not attack the base vinyl chloride sheet, and is superior to the vinyl chloride sheet. Through this effect, when applied as a magnetic ink to a thin vinyl chloride base material, a coating film with extremely good adhesion is formed, and moreover, there is almost no warping phenomenon over time. It never happens.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples. Note that all parts and percentages in Examples and Comparative Examples are based on weight.

Synthesis Example 1 Polytetramethylene glycol 1 mol (1,000 parts) (OH value 56, molecular weight 2,000) m-TMXD 12 mol (244 parts) Tin catalyst 0.2 parts The above components were mixed in methyl ethyl ketone with a solid content of 75%. The mixture was added and mixed in such a proportion that the mixture was reacted for 6 hours at the boiling point of methyl ethyl ketone, and then methyl ethyl ketone was added to dilute the solid content to 50% to obtain a terminal isocyanate prepolymer. The molecular weight of this terminal isocyanate prepolymer is approximately 2,560,
NC0% was 1.64.

Next, 31.5 parts of infrondiamine, 0.25 parts of dibutylamine, 26.6 parts of isopropyl alcohol, and 48 parts of methyl ethyl ketone were placed in a reaction vessel.
100 parts of the 50% solution of the above terminal isocyanate prepolymer was added to the solution while stirring at a temperature of 0°C.
A polyurethane polyurea resin was obtained by reacting at a temperature of 60°C to 60°C for 2 hours. The molecular weight of the obtained polyurethane polyurea resin was about 43.200.

Synthesis Example 2 100 parts of the 50% solution of the terminal isocyanate prepolymer obtained in Synthesis Example 1 was placed in a reaction vessel, and heated at 30 to 40°C.
3.15 parts of isophoronediamine while stirring at a temperature of
Dibutylamine 0.25 parts Isopropyl alcohol 26
．． 6 parts and 48 parts of methyl ethyl ketone were added thereto and reacted at a temperature of 50 to 60°C for 2 hours to obtain a polyurethane polyurea resin. The molecular weight of the obtained polyurethane polyurea resin was 48,400.

Example 1 Barium ferrite 30 parts Polyurethane polyurea resin obtained in Synthesis Example 1 40 parts Isopropyl alcohol 15 parts Toluene
A magnetic ink was obtained by kneading 15 parts of the above blend in a sand mill for 48 hours.

Example 2 7 Fet03 30 parts Polyurethane polyurea resin obtained in Synthesis Example 2 40 parts Isopropyl alcohol 15 parts Toluene
A magnetic ink was obtained by kneading 15 parts of the above blend in a sand mill for 48 hours.

Comparative Example 1 7-Fe20340 parts Polyamide resin 10 parts (product name: Reomite 52600 Kao Corporation product) Ethanol 20 parts Toluene
A magnetic ink was obtained by kneading 30 parts of the above blend in a sand mill for 48 hours.

Comparative Example 2 Barium ferrite 30 parts Polyurethane resin 15 parts (trade name: Daiferamin? IAU5022, Dainichiseika Chemical Co., Ltd. product) Toluene 25 parts Methyl ethyl ketone 30 parts The above materials were kneaded in a sand mill for 48 hours to obtain a magnetic ink.

The magnetic ink obtained in the above Examples and Comparative Examples was
A magnetic card was prepared by coating a 0μ polyvinyl chloride sheet to a thickness of 10μ and drying at 90°C for 30 seconds. A curling test was conducted on each of the cards obtained, and the results are shown in Table 1.

Note that the degree of curl in Table 1 is shown as the average value of the heights from the horizontal plane (the heights) measured at the four corners of a sheet measuring 300 wm in length and 200 wm in width.

From the results shown in Table 1, it can be seen that the magnetic card of Example 1.2 has significantly reduced changes in Bekarl degree over time compared to that of Comparative Example 1.2 having a conventional configuration.

〔Effect of the invention〕

Since the magnetic ink for magnetic cards of the present invention uses a special polyurethane polyurea resin as its binder component, it can be made into an ink using a solvent mainly composed of alcoholic solvents. Therefore, the vinyl chloride sheet is not attacked by the solvent of this ink, and the non-curl property is extremely good.

Furthermore, since the binder has excellent adhesion, it can be expected to be useful as a magnetic ink for thin film private cards made mainly of polyvinyl chloride sheets.

Applicant: Dainichiseika Industrial Co., Ltd. Agent: Patent Attorney Masaya Takahata

Claims (1)

[Scope of Claims] 1. A vinyl chloride-based magnetic ink for magnetic cards, characterized in that the binder for the ferromagnetic particles is a polyurethane polyurea resin soluble in an alcoholic solvent. 2. The polyurethane polyurea resin according to claim 1, wherein the polyurethane polyurea resin is a polyurethane polyurea obtained by chain-extending a terminal isocyanate prepolymer, which is a reaction product of a bifunctional polyol and a diisocyanate compound represented by the following general formula, with a diamine. Magnetic ink for vinyl chloride magnetic cards. General formulas ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼