JPH021360A - Recording sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a sheet with excellent recording permeability with water-based ink, and particularly to a sheet with excellent writing permeability with water-based pens, inkjet printing, etc.
The present invention relates to a recording sheet that is highly suitable for use in various types of printers that use aqueous ink, such as pen printers.

``Prior art'' Plastic films, metallized paper, metal foils, film laminates, etc. are currently used in various fields, but they have poor recording suitability with water-based inks, which may cause problems depending on the application. be.

For example, plastic films are widely used as projection recording sheets used in overhead projectors (hereinafter referred to as OHP). When a plastic film sheet is used, characters and drawings can be easily copied from documents, documents, etc. using an electronic copying machine such as Xerofukus, and a clearer projected image can be obtained by ○tfP. However, text and drawings produced by such copying machines are generally monochromatic, and in order to make them visually appealing, it is effective to convert them into colors.

However, when using a plastic film sheet such as ordinary polyethylene telescrate, it is necessary to paste a colored film on it or write and color it with an oil-based pen, and it is necessary to write with a water-based pen or water-based marker. However, there was a problem that it could not be colored. Furthermore, inkjet blink and water-based pen block that use water-based ink
etc., there was a problem that sufficient records could not be obtained.

Conventionally, plastic films coated with a resin such as polyester have been commercially available as OHP films in order to improve the fixability and image density of 1-ners used in electronic copying machines, but such films cannot be used with water-based inks. The problem was that it had poor writing and drying properties, and had no absorbency or fixing properties.

``Problems to be Solved by the Invention'' The present invention solves the above-mentioned problems, that is, the recording layer maintains water resistance and has good writability, absorbency, drying property, and fixability with a writing instrument using water-based ink. It is an object of the present invention to provide a recording sheet that can be written on and colored with a water-based pen, a water-based marker, a fountain pen, etc., and that can also be printed with excellent quality using an inkjet printer, pen plotter, etc. that uses water-based ink. purpose.

"Means for Solving the Problem" The present invention provides -0-(CIl□-CI+2-
0) Polyoxyethylene represented by r (10≦n≦15
The main component is a hydrophilic ionizing radiation-curable resin prepolymer having 0) as a skeleton and ionizing radiation-curable ethylenically unsaturated groups at both ends, and a recording layer cured by irradiation with ionizing radiation is provided. This is a recording sheet 1-.

"Function" The support used in the present invention is not particularly limited, and examples thereof include plastic films, metal foils, metallized paper, film laminated paper, coated paper, and old paper, and the recording properties with respect to water-based inks of these supports are not limited. can be improved. However, since a transparent recording layer is obtained in the present invention, it is particularly suitable for applications that require transparency, such as OHP films. plastic film is used. Examples of plastic films include polypropylene, polyethylene, and polycarbonate, but when using an electronic copying machine, use films with excellent heat resistance such as polyester, polysulfone, cellulose ester, polyamide, and polyimide. is desirable.

In the present invention, the skeleton is polyoxyethylene (10≦n≦150) represented by 10-(CH□-CH□-Chui 7),
It is characterized in that a hydrophilic ionizing radiation-curable resin prepolymer having ionizing radiation-curable ethylenically unsaturated groups at both ends is used as the main component of the recording layer.

Here, if n is less than 10, the hydrophilicity will be insufficient,
Also, when cured with ionizing radiation, the cure density becomes too high,
If it exceeds 150, the strength of the cured coating film becomes weak and sufficient water resistance cannot be obtained.

In addition, the ethylenically unsaturated groups of the above prepolymer may be directly introduced into both ends of polyoxyethylene, but by interposing diisocyanate and bonding (meth)acrylate containing a hydroxyl group, urethane (meth)acrylate can be formed. It is more preferable to provide a structure because a coating film with excellent curability and toughness can be obtained.

Here, the diisocyanate is not particularly limited, and includes, for example, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate,
Examples include 4,4'-methylenebis(cyclohexyl isocyanate), methylcyclohexane 2,4(2,6) diisocyanate, 1,3-(isocyanatomethyl)cyclohexane, and trimethylhexamethylene diisocyanate.

A preferable structural formula of the above-mentioned ionizing radiation-curable resin prepolymer is, for example, one represented by the following formula (1).

In addition, R in the formula is a hydrogen atom or a methyl group, R1, R2
represents an aliphatic group, a cycloaliphatic group or an aromatic group.

II II 11CIl□=
CR-C-0-R+-0-C-NH-Rz-Nll-C
-0-(Cll□-CI+2-0→1I
II II-C-NH-R2-N11
-C-0-r? l-0-C-CR=CII□CI] The prepolymer having the above structure is known as a prepolymer for immobilizing enzymes and bacterial cells, but it can be used for recording on a recording sheet, which is a feature of the present invention. It was discovered that it has extremely excellent effects when used as a main component of a layer coating composition, and the present invention was finally completed.

The reason why a recording sheet with excellent recording properties using aqueous ink and water resistance can be obtained in the present invention is not necessarily clear, but it is believed to be due to the following reasons.

That is, the ionizing radiation-curable resin prepolymer as described above, which is a specific component of the present invention, is hydrophilic, has ionizing radiation-curable ethylenically unsaturated groups at both ends, and has a chain structure of an appropriate length. This is thought to be because a recording layer consisting of a hydrophilic cured film having an appropriate crosslink density is formed by irradiation with ionizing radiation. In other words, since this recording layer has a relatively weakly hydrophilic network structure, it is assumed that it has water absorbing ability while maintaining water resistance, and water-based ink is quickly absorbed and fixed. Ru.

The coating composition for a recording layer of the present invention contains the above-mentioned ionizing radiation-curable resin prepolymer as a product component, but for the purpose of controlling crosslinking density, hydrophilicity, etc., ionizing radiation-curable monomers other than the above-mentioned prepolymer and Oligomers can be mixed as appropriate. Such monomers and oligomers have good compatibility with the above-mentioned prepolymer, and for the purpose of improving the writability of water-based ink, it is desirable that they be hydrophilic.Specifically, the following are exemplified. Ru.

(a) Monofunctional monomer or oligomer; (i) (ivy) acrylic acid, CH□-C1?・COO・(C1h
-CHR-Coo), -H (1≦n≦2OR represents a hydrogen atom or a methyl group), an ethylenically unsaturated monocarboxylic acid such as (meth)acrylic acid dimer (meth)acrylic acid trimer, or Monofunctional monomers or oligomers containing carboxyl groups such as ethylenically unsaturated polycarboxylic acids, and monofunctional monomers or oligomers containing carboxylic acid groups such as alkali metal salts, ammonium salts, and amine salts thereof. ) Ethylenically unsaturated (meth)acrylamide or alkyl-substituted (meth)acrylamide, amide group-containing monofunctional monomers or oligomers represented by N-vinylpyrrolidone, etc. (c) Sulfones represented by aliphatic or aromatic vinyl sulfonic acids Acid group-containing monofunctional monomer or oligomer,
and sulfonic acid group-containing monofunctional monomers such as alkali metal salts, ammonium salts, and amine salts thereof, or OH group-containing monofunctional monomers such as (di)2-hydroxyethyl (meth)acrylate, or oligomers (v)glycidyl (meth)acrylate. ) Monofunctional monomers or oligomers containing epoxy groups such as acrylates (f) Monofunctional monomers or oligomers containing quaternary ammonium bases (b) Multifunctional monomers or oligomers; (a) Ethylene glycol di(meth)acrylate, diethylene glycol di A condensate of polyhydric alcohol or polyhydric alcohol condensate and multiple (meth)acrylic acids, such as (meth)acrylate, polyethylene glycol di(meth)acrylate, glycerin tri(meth)acrylate, etc.

(b) N,N″-methylenebis(meth)acrylamide.

(c) Acrylamide or acrylamide 1F44
At least the following CU3 formula % formula % ((R represents a hydrogen atom or a methyl group ) is a natural or synthetic water-soluble polymer compound.

In addition, natural polymer compounds include casein, gelatin, starch-based polyesters (dex), phosphorus, soluble starch, pregelatinized starch, Burilan, etc.) and their derivatives, cellulose derivatives, trocellulose, carboxylic acid, etc. methylcellulose, methylcellulose, hydroxypropylmethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxyprobilcellulose, etc.).

Examples of the synthetic polymer compound include completely saponified or partially saponified polyvinyl alcohol.

(d) (meth)acryloyl group, haloalkyl (meth)
Polyvinyl alcohol and the like having at least one functional group selected from acryloyl group and N-methylol acrylamide.

Furthermore, if necessary, for example, antistatic agents, lubricants, dispersants, dyes, pigments, anti-blocking agents, wetting agents, leveling agents, antifoaming agents, and ionizing radiation curable resins and non-ionizing radiation curable resins other than those mentioned above. A mold resin can also be added within a range that does not impede the effects of the present invention.

The recording layer coating composition of the present invention is coated on at least one side of the support, and in this case, the coating means include a bar coater,
This is carried out using a conventional coating machine such as a roll coater, air knife coater, or gravure coater.

Although the coating composition used in the present invention may be prepared as an anhydrous or solvent-free composition, it is usually diluted with a solvent, preferably water, in order to lower the viscosity.

If the amount of water or solvent is small, the water or solvent may evaporate and dry when irradiated with ionizing radiation, but especially when the solid content concentration is low, Requires a drying step later.

The coating amount of the above coating composition is 0.1 to 20 g/solid amount.
n (preferably in the range of 0.2 to Log/r4.Incidentally, if it is less than 0.1 g/rd, the desired effect of the present invention will hardly be obtained, and if it is more than 20 g/n, the effect will not be obtained. has become saturated and is no longer necessary.

The coated surface of the support may be pretreated as necessary by anchor coating treatment, corona discharge treatment, radiation treatment, plasma treatment, etc. to improve the wettability of the coated surface and to improve the adhesion with the recording layer. It can be improved.

In the method of the present invention, the coating composition layer formed as described above is cured by irradiation with ionizing radiation. Examples of ionizing radiation include electron beams, ultraviolet rays, α, +, i, β rays, γ rays, Examples include X-rays. α rays, β rays, γ rays and X
Since radiation is associated with the problem of danger to the human body, electron beams and ultraviolet rays are preferably used because they are easy to handle and are widely used industrially.

When using an electron beam, the amount of electron beam irradiated is 0.1~
It is desirable to adjust within a range of about 20 Mrad. 0.
If it is less than 1 Mrad, sufficient irradiation effect cannot be obtained;
Irradiation in excess of Mrad is undesirable because it may deteriorate the support, especially paper and some types of plastics. As the electron beam irradiation method, for example, a scanning method, a curtain beam method, a beam method, etc. are adopted, and the acceleration voltage when irradiating the electron beam is If) 0 to 3.
Approximately 00KV is appropriate. Incidentally, electron beam irradiation has the advantage that productivity is higher than that of ultraviolet irradiation, and problems of odor and coloring due to the addition of a sensitizer do not occur.

When using ultraviolet rays, it is necessary to incorporate a sensitizer into the coating composition, such as thioxanthone, hengeine, benzoin alkyl ether xanthone, dimethylxanthone, hensifhenone, anthracene, 2,2-jetoxyacetophenone, hensyl. dimethyl ketal,
Hensyl diphenyl disulfide, anthraquinone, ■
-chloroanthraquinone, 2-ethylanthraquinone,
One or more sensitizers such as 2-terbutylanthraquinone, N,N"-tetraethyl-4,4"-diaminobenzophenone, and 1.1 dichloroacetophenone are appropriately blended.

The amount of the sensitizer used is 0.2 to 10% by weight, preferably 0.5% by weight, based on the ionizing radiation-curable component in the coating composition.
It is desirable to adjust the amount within a range of about 5% by weight. Furthermore, in addition to such sensitizers, to accelerate curing, e.g. triethanolamine, 2-dimethylaminoethanol, dimethylaminobenzoic acid, isoamyl dimethylaminobenzoate, dioctylaminobenzoic acid, lauryl dimethylaminobenzoate, It is also possible to blend tertiary amines such as 0.05 to 3% by weight based on the ionizing radiation curable component in the coating composition.

As a light source for ultraviolet irradiation, 1 to 50 ultraviolet lamps (for example, low-pressure, medium-pressure, high-pressure mercury lamps with operating pressures from several mmHg to about 10 atmospheres), xenon lamps, tungsten lamps, etc. are used. ~800
Ultraviolet light having an intensity of about 0 p W /cm2 is preferably irradiated.

"Examples" The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these Examples. Also,
Unless otherwise specified, parts and percentages in the examples refer to parts by weight and percentages by weight, respectively.

Examples 1 to 3 The following (1
) with a dry weight of 5 g/
n (), and then using an electron beam irradiation device (Electro Curtain CB150: manufactured by E S f)
Three types of recording sheets were obtained by irradiating an electron beam of 5 Mrad using a .

(Ill) (Example 1) A 50% aqueous solution of ENT2000 (Kansai Paint Co., Ltd.) was used as a hydrophilic ionizing radiation-curable resin prepolymer having the structure of formula (III).Average molecular weight of acid prepolymer is about 2,700, and nζ45 in formula (III) is about 200 chains long.

(Example 2) A 50% aqueous solution of ENTlooO (manufactured by Kansai Paint Co., Ltd.) was used as a hydrophilic ionizing radiation-curable resin prepolymer having the structure of formula [III]. The average molecular weight of the prepolymer is about 1700, and n in the formula (In)
ζ23, the chain length is about 100 people.

(Example 3) A 50% aqueous solution of ENT3400 (Kansai Paint Co., Ltd. type) was used as a hydrophilic ionizing radiation-curable resin prepolymer having the structure of formula (III). The average molecular weight of the prepolymer is about 3800, and n# in the formula [■]
70, the chain length is about 400 people.

Example 4 (a) 600 parts of a 50% aqueous solution of E N T 2000 (solid content 300 parts), (b) 50% aqueous solution of acrylamide? 8 liquid 200 parts (solid content 100 parts), (C) polyethylene glycol diacrylate (KAYARAD P
EG400DA; manufactured by Nippon Kayaku Co., Ltd.) 100 copies, (d
) A recording sheet i~ was obtained in the same manner as in Example 1 except that a mixed composition consisting of 100 parts of water was used.

Example 5 Polyethylene glycol diacryle-1 (NK Ester A 1000/Shin Nakamura Chemical Co., Ltd. style) having the structure of the formula [■] in which acryloyl groups were introduced at both ends of polyethylene glycol with an average molecular weight of 1 too A recording sheet was obtained in the same manner as in Example 1 except that a 50% aqueous solution was used.

CIIz=C11-C-0-4C11z-C1tz-0
)-rr-C-ClbCIIz(nki23)
(■) Comparative Examples 1 and 2 A coating composition consisting of a non-ionizing radiation-curable water-soluble polymer as shown below was coated on the same support as that used in the examples so that the dry weight was 2 g/rrr. Apply and 100°
A recording sheet was obtained by drying at C for 5 minutes.

(Comparison example 1) Polyvinyl alcohol (PVA-117; manufactured by Kuraray ■)
of 10% water at night.

(Comparative Example 2) 2% aqueous solution of thorium acrylate polymer (average molecular weight approximately 2 million).

Comparative Example 3 A hydrophobic ionizing radiation-curable oligomer (bifunctional oligoester acrylate-1 with acryloyl groups at both ends) was prepared on a support similar to that used in Example.
6100 (manufactured by Toagosei Kagaku Kogyo 9(1)) was applied so that the dry weight was 5 g/n, and then an electron beam of 5 Mrad was irradiated in the same manner as in the example.

Comparative Example 4 Example 5 [[
■] In the second part, polyethylene glycol diacrylate (KAYARADP [EG400DA/
5g dry weight of 50% aqueous solution of Nikki Kayaku Co., Ltd.)
/r+(), and then irradiated with an electron beam of 5 Mrad in the same manner as in the example.

Regarding the nine types of recording sheets obtained as above,
The writing properties, fixing/drying properties, water resistance, and solvent resistance of the water-based inks were evaluated using the following evaluation methods, and the results are shown in Table 1.

[Writability of water-based ink]

It was written on a recording sheet using a water-based fluorescent marker (manufactured by KOKUYO), and the presence or absence of flickering was visually determined.

◎: No repelling occurred at all.

○: Although there was some difficulty, it was at a level that caused no practical problems.

Δ: There was repellency, which was at a practically problematic level.

×: The repellency was so bad that it was impossible to write.

[Fixing/drying properties of water-based ink] After writing on a recording sheet using a water-based fluorescent marker (manufactured by KOKUYO), the time required for the ink to be fixed was evaluated by lightly rubbing it with a finger.

It was fixed within 0.025 seconds.

○: It was fixed within 60 seconds and was at a level that caused no practical problems.

Δ: Fixing took 60 seconds to 24 hours, leaving problems in practical use.

×: The recording was not fixed even after 24 hours, and the recording disappeared when rubbed with a finger.

[Water Resistance] Three drops of water were dropped onto the recording layer using a dropper and wiped off with gauze, after which scratches on the recording layer were evaluated.

◎: There were no scratches on the recording layer.

○: There was slight damage, but it was at a level that caused no practical problems.

×: The entire recording layer was wiped off.

[Solvent Resistance] Three drops of toluene were dropped onto the recording layer using a dropper, and damage to the recording layer was evaluated after wiping it off with gauze.

◎: There was no damage to the recording layer at all.

Table 1 "Effects" As is clear from Table 1, the recording sheet according to the present invention has a recording layer with excellent writing properties, fixing and drying properties for water-based inks, and excellent water resistance and solvent resistance. was. Further, as a result of copying with an electronic copying machine using the recording sheet obtained in the example, one with excellent fixing properties and image density of 1 to toner was obtained. Furthermore, the copied characters and designs could be easily marked with a water-based marker, and when projected onto a screen using an OHP, a clear projected image with high contrast was obtained.

As mentioned above, the recording sheet 1- obtained in the present invention is OH
It had a high commercial value as a film for P, etc., and had extremely excellent writing suitability for water-based inks.

Claims (2)

[Claims] (1) On the support, -O■CH_2-CH_2-O■_
Polyoxyethylene represented by n (10≦n≦150)
The main component is a hydrophilic ionizing radiation-curable resin prepolymer having a skeleton of Recording sheet. (2) Ionizing radiation-curable resin prepolymer is urethane (
The recording sheet according to claim (1), having a meth)acrylate structure.