JPH0566865B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a recording sheet that has excellent suitability for recording with water-based inks, and particularly for recording sheets that have excellent suitability for writing with water-based pens and for various types of printers that use water-based inks, such as ink jets and pen plotters. Regarding the seat. (Prior technology) Plastic film, metallized paper, metal foil,
Although film-laminated paper and the like are currently used in various fields, problems may arise depending on the use because they are poor in recording suitability with water-based inks. For example, plastic film is widely used as a projection recording sheet for overhead projectors (hereinafter abbreviated as OHP) by copying characters and drawings from books, literature, etc. using an electronic copying machine such as Xerox. However, the letters and drawings produced by such copiers are generally monochrome, and it is effective to make them in color to make them visually appealing. There is a problem in that it cannot be written on or colored with a marker, and there is also a problem in that sufficient recording cannot be obtained even with an inkjet or a water-based pen plotter using water-based ink. In addition, plastic films coated with resins such as polyester are also commercially available as OHP films in order to improve toner fixability and image density in electronic copying machines, but such films cannot be used with water-based inks. Poor writing and drying properties,
It has the disadvantage of not having any absorbency or fixing properties. (Problems to be Solved by the Invention) The present invention solves the above-mentioned problems, has excellent writing properties, absorbency, drying properties, and fixing properties of water-based ink, and allows writing and coloring with water-based pens and water-based markers. ,
Another object of the present invention is to provide a recording sheet that can be printed and printed with excellent quality using an inkjet printer, a pen plotter, or the like using water-based ink. (Means for Solving the Problems) The present invention provides (a) ionizing radiation-curable hydrophilic monofunctional monomers and/or oligomers and (b)
This is a recording sheet characterized in that a recording layer is formed by coating a mixed composition containing an ionizing radiation-curable polyfunctional monomer and/or oligomer and irradiating it with ionizing radiation. (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 plain paper. Although it can be improved, plastic film is mainly used from the viewpoint of transparency, especially when used for OHP purposes. Plastic films include polypropylene, polyethylene,
Examples include polycarbonate, but when using an electronic copying machine, it is particularly desirable to use films with excellent heat resistance such as polyester, polysulfone, cellulose ester, polyamide, polyimide, etc. In the present invention, first, a mixed composition containing (a) an ionizing radiation-curable hydrophilic monofunctional monomer or/and oligomer and (b) an ionizing radiation-curable polyfunctional monomer or/and oligomer is placed on the support. Examples of (a) ionizing radiation-curable hydrophilic monofunctional monomers and/or oligomers include the following. (a) (Meth)acrylic acid, CH ₂ = CR・COO・
Ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid dimer and (meth)acrylic acid trimer represented by ( _CH2・CHR・COO) _o・H (n≧1, R is H or _CH3 ), or monofunctional monomers or oligomers containing a carboxyl group represented by ethylenically unsaturated polycarboxylic acids, and monofunctional monomers or oligomers containing carboxylic acid groups such as alkali metal salts, ammonium salts, and amine salts thereof. (b) Ethylenically unsaturated (meth)acrylamide or alkyl-substituted (meth)acrylamide, N-
A monofunctional monomer or oligomer containing an amide group, such as vinylpyrrolidone. (c) sulfonic acid group-containing monofunctional monomers or oligomers represented by aliphatic or aromatic vinyl sulfonic acids, and alkali metal salts thereof;
Monofunctional monomers or oligomers containing sulfonic acid groups such as ammonium salts and amine salts. (d) OH group-containing monofunctional monomers or oligomers such as 2-hydroxyethyl (meth)acrylate. (e) Epoxy group-containing monofunctional monomers or oligomers such as glycidyl (meth)acrylate. (f) A monofunctional monomer or oligomer containing a quaternary ammonium base. Among the above, (a) and (b) are particularly preferably used because they are excellent in the desired effects of the present application. (b) Ionizing radiation-curable polyfunctional monomer or/
The oligomer is not particularly limited as long as it has two or more ionizing radiation-curable unsaturated double bonds; for example, polyfunctional monomers such as hexanediol diacrylate, trimethylolpropane triacrylate, pentane erythritol triacrylate, etc. Alternatively, it is also possible to use ordinary polyfunctional oligomers such as polyester acrylate, epoxy acrylate, urethane acrylate, etc., but those that have good copolymerizability with the above (a), efficiently form a crosslinked structure, and provide a uniform crosslinking distribution. In addition, those exhibiting hydrophilicity are preferred because they have good compatibility with (a) and are suitable for recording with aqueous inks. Examples of such monomers or oligomers exhibiting hydrophilicity include the following. (b) Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, glycerin tri(meth)acrylate, etc. Representative polyhydric alcohols or polyhydric alcohol condensates and condensates of multiple (meth)acrylic acids. (b) N,N'-methylenebis(meth)acrylamide (c) Polybasic acids and allyls represented by diallyl phthalate, diallyl maleate, diallyl terephthalate, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, etc. alcohol ester. (d) By reacting acrylamide or an acrylamide derivative with a (di)aldehyde such as glyoxal in the presence of a catalyst, at least one radiation-reactive functional group is added to the side chain. (R represents a hydrogen atom or an alkyl group) A natural or synthetic water-soluble polymer compound. Natural polymer compounds include casein, gelatin, starch polysaccharides (dextrin, soluble starch, pregelatinized starch, Brilan, etc.) and their derivatives, and cellulose derivatives [nitrocellulose, carboxymethylcellulose (CMC), methylcellulose (MC), etc.] ), hydroxypropyl methylcellulose (HPMC), ethylcellulose (EC), hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), etc. Examples of the synthetic polymer compound include completely saponified or partially saponified polyvinyl alcohol. (e) Polyvinyl alcohol and the like having at least one functional group selected from a (meth)acryloyl group, a haloalkyl (meth)acryloyl group, and N-methylolacrylamide. Among these, (a), (b), and (d) are preferably used because they are easily hardened by ionizing radiation. The mixing ratio of (a) ionizing radiation-curable hydrophilic monofunctional monomers and/or oligomers and (b) ionizing radiation-curable polyfunctional monomers and/or oligomers must be selected appropriately depending on the respective types. However, if the proportion of (a) is small, sufficient writing and fixing properties of water-based ink cannot be obtained, and if the proportion of (a) is too large, the water resistance of the recording layer will be poor. The weight ratio of (a):(b) is 98:2 to 20:
80, preferably in the range of 90:10 to 50:50. The reason why a sheet with excellent recording performance with water-based ink can be obtained in the present invention is that (a) and (b) are efficiently copolymerized to form a recording layer consisting of a hydrophilic cured film with an appropriate crosslinked structure. It is thought that this is because the That is,
This recording layer has a hydrophilic network structure, so it maintains water resistance and has water absorption ability.
It is presumed that water-based ink is also quickly absorbed and fixed. The reasons why monofunctional monomers and/or oligomers were specifically selected as (a) ionizing radiation-curable hydrophilic monomers and/or oligomers were as follows:
This is because if it is polyfunctional, the cured density will be too high, resulting in a recording layer with poor water absorption ability. In the present invention, when (c) a polymer having a hydrophilic group is further blended with the above (a) and (b) as a mixed composition for forming a recording layer, the effect of the present invention, that is, the writability of aqueous ink. It is possible to suppress the occurrence of curling due to curing shrinkage after irradiation with ionizing radiation, without impeding fixing, drying properties, etc. (c) Polymers having hydrophilic groups include, for example, carboxyl groups, sulfonic acid groups, carboxylic acid groups, sulfonic acid groups, hydroxyl groups, ether groups, acid amide groups, primary to tertiary amino groups, and quaternary ammonium groups. It is a polymer having hydrophilic groups such as. (c) Polymers having hydrophilic groups are usually water-soluble, such as poly(meth)acrylic acid and its salts, polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, starch,
Examples include polyacrylamide, polyvinylpyrrolidone, acrylic acid-vinyl alcohol copolymer, and the like. In addition, in the recording sheet of the present invention, especially when a graft polymer and/or a block polymer having a hydrophilic segment is blended as (c) the polymer having a hydrophilic group, the effect of the present invention, that is, the writability of the water-based ink can be improved. , fixing and drying properties are further improved, and the occurrence of curling due to curing shrinkage after irradiation with ionizing radiation can be suppressed. The reason why the effect of the present invention is further improved by blending these graft polymers and/or block polymers is not necessarily clear, but the presence of these polymers increases the efficiency of copolymerization of (a) and (b). It is presumed that this is because it takes a crosslinked structure, which is often carried out and is more favorable in terms of ink absorption. The above-mentioned graft polymer and/or block polymer are functionally separated polymers in which two or more types of segments with different properties exist in a separated form, unlike ordinary random polymers, and at least one of these segments is strongly hydrophilic. It is preferable that the material has a certain property. Here, examples of segments with strong hydrophilicity include (meth)acrylic acid, acrylamide, and N-
Single polymers such as methylol acrylamide, hydroxyethyl (meth)acrylate, vinyl pyrrolidone, vinyl alcohol, or two of these
Examples include copolymers of more than one type. Specifically, graft polymers such as comb-shaped polymers in which branch chains are composed of polyN-methylolacrylamide, etc., and trunk chains are composed of copolymers of methyl methacrylate and hydroxyethyl methacrylate, polymethyl methacrylate, polyhydroxyethyl methacrylate, etc.; A hydrophilic block polymer having polyhydroxyethyl methacrylate segments and polymethyl methacrylate segments is exemplified. (c) The blending amount of the polymer having a hydrophilic group is appropriately adjusted depending on the type, but the weight ratio [(a) +
(b)〕:(c) is 98:2~20:80, preferably 90:10~
Used in the 40:60 range. In this case, if the amount of (c) blended is small, a sufficient curl prevention effect cannot be obtained, and if it is too large, the water resistance of the recording layer may decrease depending on the type.
The following problems arise when the strength of the coating decreases. The coating compositions forming the recording layer of the present invention are (a) and (b).
Or, the main components are (a), (b) and (c),
For example, antistatic agents, lubricants, dispersants,
Dyes, pigments, anti-blocking agents, wetting agents, leveling agents, antifoaming agents, as well as other ionizing radiation-curable resins not included in (a) and (b) and other polymers not included in (c) etc. can also be added within a range that does not impede the effects of the present invention. The coating composition thus prepared is applied to at least one side of the support by a conventional coating means such as a bar coater, roll coater, air knife coater, or gravure coater. Coating compositions containing (a) and (b) may be prepared in an anhydrous or solvent-free manner, but generally when (c) a polymer having a hydrophilic group is added to the coating composition, water Must be diluted or dissolved in solvent, water,
A coating composition based on a solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, or a mixed solvent thereof is used. If the amount of water or solvent is small, the water or solvent may evaporate and dry when irradiated with ionizing radiation.
Particularly when the solid content concentration is low, a drying step is required before and/or after irradiation with ionizing radiation. The coating amount of the above coating composition is 0.1 to 20 in terms of solid amount.
g/m ² preferably ranges from 0.5 to 10 g/m ² .
Incidentally, if it is less than 0.1 g/m ^{2 ,} the desired effect of the present invention will hardly be obtained, and if it is more than 20 g/m ² , the effect will reach a saturated state and it is not 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 of the recording layer. can be improved. In the recording sheet 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, alpha rays, beta rays, gamma rays, and X-rays. etc. Since alpha rays, beta rays, gamma rays, and X-rays are associated with problems such as 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
It is desirable to adjust within the range of about 0.1 to 20 Mrad. If the irradiation is less than 0.1 Mrad, a sufficient irradiation effect cannot be obtained, and if the irradiation exceeds 20 Mrad, it 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 broad beam method, etc. are adopted, and an appropriate acceleration voltage for electron beam irradiation is about 100 to 300 KV. The electron beam irradiation method has higher productivity than ultraviolet irradiation, has no problems with odor or coloration due to the addition of a sensitizer, and has the advantage of easily forming a uniform crosslinked structure. When using ultraviolet light, it is necessary to incorporate a sensitizer into the coating composition, such as thioxanthone, benzoin, benzoin alkyl ether xanthone, dimethylxanthone, benzophenone, acetracene, 2,2-diethoxyacetophenone, Benzyl dimethyl ketal, diphenyl disulfide, anthraquinone, 1-chloroanthraquinone, 2-ethylanthraquinone, 2-
ter-butylanthraquinone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 1,1
-One or more sensitizers such as dichloroacetophenone are appropriately blended. The amount of sensitizer to be used is 0.2 to 0.2 to 0.2 to 0.2 to 0.2 to 0.2 to 0.2 to 0.2 to 0.0 to 1.0 of the ionizing radiation-curable monomer/oligomer in the coating composition.
It is desirable to adjust the content within the range of 10% by weight, preferably 0.5 to 5% by weight. Furthermore, in addition to such sensitizers, for example triethanolamine, 2-dimethylaminoethanol, dimethylaminobenzoic acid, isoamyl dimethylaminobenzoate, dioctylaminobenzoic acid,
Tertiary amines such as lauryl dimethylaminobenzoate can also be blended in an amount of about 0.05 to 3% by weight based on the ionizing radiation curable monomer/oligomer in the coating composition. Light sources for ultraviolet irradiation include 1 to 50 ultraviolet lamps (for example, low-pressure, medium-pressure, high-pressure mercury lamps with operating pressures from a few mmHg to about 10 atmospheres);
A xenon lamp, a tungsten lamp, or the like is used, and ultraviolet rays having an intensity of about 5000 to 8000 μW/cm ² are preferably irradiated. (Example) The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these.
In addition, unless otherwise specified, "part" and "%" in examples
represent "parts by weight" and "% by weight", respectively. Example 1 Polyethylene terephthalate film (thickness 100μ) treated with thermosetting resin anchor coating
m) the following mixed composition on top with a dry weight of 4 g/m ²
Then, using an electron beam irradiation device (electron curtain CB150: manufactured by ESI)
A recording sheet was obtained by irradiating it with a 5 Mrad electron beam. Mixed composition: (a) 50% aqueous solution of acrylamide as an ionizing radiation-curable hydrophilic monofunctional monomer
100 parts (solid content 50 parts), (b) Polyethylene glycol diacrylate (KAYARAD PEG400DA; Nippon Kayaku) as an ionizing radiation-curable polyfunctional monomer
Co., Ltd. (25 parts) and (c) a comb-shaped polymer whose branch chain is polyN-methylolacrylamide and whose main chain is a copolymer of methyl methacrylate and hydroxyethyl methacrylate as a graft polymer with a hydrophilic segment ( LH48; Soken Chemical Co., Ltd.
100 parts of 25% methylocellosolve solution (solid content
25 parts) mixed composition. Example 2 Example 1 except that the mixed composition was as follows.
A record sheet was obtained in the same manner. Mixed composition: (a) 50% aqueous solution of acrylamide as an ionizing radiation-curable hydrophilic monofunctional monomer66
(solid content 33 parts), (b) Polyethylene glycol diacrylate (KAYARAD PEG400DA; Nippon Kayaku Co., Ltd.) as an ionizing radiation-curable polyfunctional monomer
(c) A comb-shaped polymer (LH48; Souken Co., Ltd.) consisting of 33 parts (LH48; Manufactured by Kagaku Co., Ltd.)
133 parts of 25% methyl cellosolve solution (33 parts solids)
mixed composition. Example 3 Example 1 except that the mixed composition was as follows.
A record sheet was obtained in the same manner. Mixed composition: (a) 50% aqueous solution of acrylamide as an ionizing radiation-curable hydrophilic monofunctional monomer
100 parts (solid content 50 parts), (b) Polyethylene glycol diacrylate (KAYARAD PEG400DA; Nippon Kayaku) as an ionizing radiation-curable polyfunctional monomer
Co., Ltd. (33 parts) and (c) a comb-shaped polymer (as a graft polymer with a hydrophilic segment, whose branch chains are polyN-methylolacrylamide and whose main chain is a copolymer of methyl methacrylate and hydroxyethyl methacrylate). LH48; Soken Chemical Co., Ltd.
68 parts of 25% methyl cellosolve solution (solids content: 17
part) mixed composition. Example 4 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: (a) 50% aqueous solution of acrylamide as an ionizing radiation-curable hydrophilic monofunctional monomer
A mixed composition similar to Example 1 except that 100 parts of a 50% aqueous solution of sodium acrylate (solid content 50 parts) with a degree of neutralization of 50% was used instead of 100 parts. Example 5 The mixed composition was as follows, and after electron beam irradiation
A recording sheet was obtained in the same manner as in Example 1, except that it was dried at 100° C. for 2 minutes. Mixed composition: (b) Polyethylene glycol diacrylate (KAYARAD PEG400DA; manufactured by Nippon Kayaku Co., Ltd.) as an ionizing radiation-curable polyfunctional oligomer
instead of 25 copies of modified polyvinyl alcohol with a functional group of 20
% aqueous solution (AT-197, Dainippon Ink and Chemicals Co., Ltd.)
Same as Example 1, except that 125 parts (solid content: 25 parts) of 100% (solid content) was used. Example 6 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: (c) a comb-shaped polymer (LH48; a graft polymer having a hydrophilic segment);
Modiper H100 (manufactured by NOF Corporation), a hydrophilic block polymer with polyhydroxyethyl methacrylate segments and polymethyl methacrylate segments, was used instead of Soken Kagaku Co., Ltd.).
100 parts of 25% methyl cellosolve solution (25 parts solids)
The same mixed composition as in Example 1 except that . Example 7 Example 1 except that the mixed composition was as follows.
A record sheet was obtained in the same manner. Mixed composition: (c) a comb-shaped polymer (LH48; a graft polymer having a hydrophilic segment);
(c) A 30% aqueous solution of Gocephaimer C-820, a styrene copolymer of quaternary ammonium acrylate ester, which is a polymer with hydrophilic groups (manufactured by Nippon Gosei Co., Ltd.). A mixed composition similar to Example 1 except that 83 parts (solid content: 25 parts) (manufactured by Kagaku Kogyo Co., Ltd.) was used. Example 8 The mixed composition was as follows, and before electron beam irradiation,
A recording sheet was obtained in the same manner as in Example 1, except that it was dried at 100° C. for 15 seconds. Mixed composition: (c) a comb-shaped polymer (LH48; a graft polymer having a hydrophilic segment);
(c) 250 parts of a 10% aqueous solution (solid content: 25 parts) of polyvinyl alcohol (PVA-117; manufactured by Kuraray Co., Ltd.), which is a polymer with hydrophilic groups. The same mixed composition as in Example 1 was used except that it was used. Example 9 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: (a) 50% aqueous solution of acrylamide as an ionizing radiation-curable hydrophilic monofunctional monomer
170 parts (solid content 85 parts), (b) Polyethylene glycol diacrylate (KAYARAD PEG400DA; Nippon Kayaku) as an ionizing radiation-curable polyfunctional monomer
Co., Ltd.) 15 parts and Florado FC170C as a wetting agent.
(manufactured by Sumitomo 3M Ltd.) A mixed composition consisting of 0.02 parts. Example 10 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: (a) 170 parts of a 50% aqueous solution (solid content: 85 parts) of sodium acrylate with a degree of neutralization of 50% was used as an ionizing radiation-curable hydrophilic monofunctional monomer; (b) an ionizing radiation-curable monofunctional monomer; 15 parts of diethylene glycol diacrylate as a polyfunctional monomer and 0.02 parts of Florado FC170C (manufactured by Sumitomo 3M Ltd.) as a wetting agent.
A mixed composition consisting of parts. Example 11 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: (a) 50% aqueous solution of acrylamide as an ionizing radiation-curable hydrophilic monofunctional monomer
50% aqueous solution of acrylamide instead of 100 parts
90 parts (45 parts solids) and 40 parts N-vinylpyrrolidone
(b) 15 parts of diethylene glycol diacrylate as an ionizing radiation-curable polyfunctional monomer and Florado FC170C (Sumitomo 3M Co., Ltd.) as a wetting agent.
A mixed composition consisting of 0.02 part of Co., Ltd.). Comparative Example 1 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: 50% aqueous solution of acrylamide 200
%, and 0.02 part of Florado FC170C (manufactured by Sumitomo 3M Ltd.) as a wetting agent. Comparative Example 2 Example 1 except that the coating composition was as follows.
A recording sheet was obtained in the same manner. Coating composition: Polyethylene glycol diacrylate (KAYARAD PEG400DA; Nippon Kayaku Co., Ltd.)
Co., Ltd.) was used as a coating composition. Comparative Example 3 Example 1 except that the coating composition was as follows.
A recording sheet was obtained in the same manner. Coating composition; 30% aqueous solution of Gocephaimer C-820, a quaternary ammonium salt ester of acrylic acid and styrene copolymer (Nippon Gosei Chemical Co., Ltd.)
Co., Ltd.). Comparative Example 4 Example 1 except that the coating composition was as follows.
A recording sheet was obtained in the same manner. Coating composition: 25% of a comb-shaped polymer (LH48; manufactured by Souken Kagaku Co., Ltd.) whose branch chains are polyN-methylolacrylamide and whose main chain is a copolymer of methyl methacrylate and hydroxyethyl methacrylate.
% methyl cellosolve solution. Comparative Example 5 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: Polyethylene glycol diacrylate (KAYARAD PEG400DA; Nippon Kayaku Co., Ltd.)
) 30 parts and comb-shaped polymer (LH48; Soken Chemical Co., Ltd.)
A mixed composition of 280 parts of 25% methyl cellosolve solution (solid content: 70 parts) manufactured by Co., Ltd. Comparative Example 6 Example 1 except that the mixed composition was as follows.
A recording sheet was obtained in the same manner. Mixed composition: 50% aqueous solution of acrylamide 100%
(solid content: 50 parts) and 200 parts of a 25% methyl cellosolve solution (solid content: 50 parts) of a comb-shaped polymer (LH48; manufactured by Souken Kagaku Co., Ltd.). Comparative Example 7 Polyethylene terephthalate film (thickness 100μ) treated with thermosetting resin anchor coating
m). Comparative Example 8 Polyethylene terephthalate film (thickness
100μm). The 19 types of recording sheets obtained as described above were evaluated in terms of water-based ink writing properties, water-based ink fixing/drying properties, water resistance, solvent resistance, and curling suitability, as shown below. 1st
Shown in the table. [Writability of water-based ink] Writing was performed on a recording sheet using a water-based marker (manufactured by KOKUYO Co., Ltd.), and the presence or absence of repellency was visually determined. ◎: No repelling occurred at all. ○: Although there was some repelling, it was at a level that caused no practical problems. △: There was repellency, which was at a practically problematic level. ×: The repellency was so severe that it was impossible to write. [Fixing and drying properties of water-based ink] After writing on a recording sheet using a water-based marker (manufactured by KOKUYO), the time required for the ink to be fixed was evaluated by rubbing lightly with a finger. ◎: Fixed within 5 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, which was at a level that was problematic in practice. ×: It was not fixed even after 24 hours, and a record could be taken by rubbing it with a finger. [Water Resistance] Five drops of water 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. Δ: There was damage to the recording layer, which was at a level that caused problems in practice. x: The entire recording layer was wiped off. [Solvent Resistance] Five drops of ethanol 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. Δ: There was damage to the recording layer, which was at a level that caused problems in practice. [Curling suitability] The curl height when the recording sheet was cut into A4 size and placed on a horizontal table was expressed in mm. ◎: Curl height 3 mm or less. ○: Curl height 3 to 10 mm. △: Curl height 10-20mm.

【table】

[Table] (Effects) The present invention is a recording sheet having a recording layer with excellent writing properties, fixing and drying properties of water-based ink, and excellent water resistance and solvent resistance. Products containing hydrophilic polymers also had excellent curlability.

Claims (1)

[Claims] 1. A mixed composition containing (a) an ionizing radiation-curable hydrophilic monofunctional monomer or/and oligomer and (b) an ionizing radiation-curable polyfunctional monomer or/and oligomer on a support. 1. A recording sheet comprising a recording layer coated with a substance and irradiated with ionizing radiation. 2. The recording sheet according to claim 1, wherein the mixed composition contains (c) a polymer having a hydrophilic group. 3. The recording sheet according to claim 2, wherein (c) the polymer having a hydrophilic group is a graft polymer and/or a block polymer having a hydrophilic segment.