JPH09207430A - Sheet for recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for recording with a coloring material receiving layer wherein after it is stored under high temp. and an high humidity or after it is stored for a long period, an image sheet with good image can be obtd. by an ink-jet recording, a heat transfer recording or an electrophotographic recording. SOLUTION: A coloring material receiving layer is provided on a substrate of a sheet for recording and this coloring material receiving layer consists of an inorg. fine particle and a water-soluble resin and the water-soluble resin is a modified polyvinyl alcohol with 1-20% ethylene units in terms of molar ratio as a repeating unit and the degree of saponification of 85%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet for recording using a color material. In particular, it relates to a recording sheet for forming an image sheet by inkjet recording, thermal transfer recording, electrophotographic recording and the like.

[0002]

2. Description of the Related Art In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and apparatuses suitable for each information system have been developed and adopted. Among such recording methods, in ink recording using an inkjet or plotter, and thermal transfer recording using a melt-type coloring material or a sublimation-type coloring material, the apparatus used is lightweight and compact, and noise is reduced. It also has excellent operability and maintainability.
Further, the apparatus used in such a recording method has been widely used recently because of easy colorization. In the conventional electrophotographic system, colorization has been advanced, and high-resolution, full-color printers and copiers have been developed and commercialized.

Various ink jet systems for color image formation have been developed. Physical properties are roughly classified into a method using a dye solution (aqueous ink) containing a water-soluble dye, and a dye containing an oil-soluble dye. There are three types, a method using a solution (oil-based ink) and a method using a low melting solid wax (wax ink) containing a dye by heat-melting. The mainstream is a type using an aqueous ink. In any case, it is a method of forming an image by ejecting liquid fine droplets onto an ink recording sheet such as paper.

There are roughly two types of heat-sensitive transfer methods. The first method is to apply heat-meltable ink coated on a support from the side of the support to form a pattern of the applied heat. The second method is a method of melting and transferring to a recording sheet to obtain an image (melt heat transfer). The second method is to use a heat-sensitive recording material composed of a resin having a high softening point and a sublimable dye on a support in the same manner as the former. Is applied, and the sublimation dye is sublimated in a heat-applied pattern to be transferred to a recording sheet such as paper to obtain an image (sublimation heat transfer). The electrophotographic method gives a light pattern to a charged photoconductive layer to form an electrostatic latent image,
The method in which the toner is transferred to a recording sheet after development and the toner is fused and fixed by heat is the mainstream.

As the recording sheet used for the image formation, paper having a colorant receiving layer formed on the surface is widely used. On the other hand, in the following applications, it is necessary to use a transparent sheet, and in many cases, a recording sheet having an image formed and imaged as described above using a transparent film having a coloring material receiving (absorption) layer on the surface. To create. For example, OH is increasingly used as a substitute for slides at conferences, etc.
P films, films for backlight displays, which have been increasingly used in place of printed posters and display boards, films for second original drawings, and the like.

The recording sheet on which an image is formed by these recording methods has the hue, saturation, and lightness of the obtained image, and
It is necessary that the color material is firmly adhered to the surface of the recording sheet, and in the case of inkjet recording, it absorbs liquid ink quickly to obtain a fine image and does not cause ink bleeding or ink accumulation. In addition, it is required that the ink does not bleed due to the adhesion of water.

To solve these problems, various proposals have been made in the past. For example, in the case of ink jet recording, JP-A-56-80489 proposes the use of a soluble or swellable substance, and a large number of polymer systems (polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyethylene oxide). (PE
O) and carboxymethyl cellulose (CMC)) have been proposed. These utilize the penetrating effect of the aqueous ink due to the hydrophilic or dissociative groups of the polymer. Even when the film is thick, a sufficient ink absorption rate cannot be obtained, and ink bleeding is not sufficiently suppressed, so that the image Resolution is not satisfactory.

In order to improve the ink absorbability, for example, JP-A-57-14091 and JP-A-61-161 are used.
Japanese Patent Laid-Open No. 19389 proposes a recording sheet comprising a transparent support and a transparent layer of colloidal silica and a water-soluble resin provided thereon. In addition, JP-A-2-2766
70 and JP-A-3-281383,
A recording sheet provided with a colorant receiving layer having pores formed from pseudo-boehmite fine particles is disclosed.

Further, in Japanese Unexamined Patent Publication No. 7-276789, the porosity of a support and silica provided on the support and having a primary particle diameter of 10 nm or less and polyvinyl alcohol is 5
A recording sheet comprising a coloring material receiving layer having a three-dimensional network structure of 0 to 80% is disclosed. This recording sheet also has greatly improved ink absorbency.

[0010]

As described above, polyvinyl alcohol is mainly used as a binder because the colorant receiving layer containing the above-mentioned inorganic fine particles has a large ink absorption rate and little ink bleeding. However, when a recording sheet having such a colorant receiving layer is printed after being stored at high temperature and high humidity or after being stored for a long period of time, the ink absorption rate is lowered or the image density becomes uneven (ink It has become clear that the image quality is deteriorated due to the uneven absorption of).

Therefore, according to the present invention, ink-jet recording, even after storage at high temperature and high humidity or after long-term storage,
An object of the present invention is to provide a recording sheet having a coloring material receiving layer, which enables an image sheet having a good image to be obtained by thermal transfer recording or electrophotographic recording. In particular, the present invention is capable of rapidly absorbing a liquid ink to obtain a fine image without ink unevenness, ink bleeding and ink accumulation, and after storage at high temperature and high humidity, or for long-term storage. It is an object of the present invention to provide a recording sheet suitable for ink jet recording in which the absorption speed of the liquid ink is not lowered and the ink absorption unevenness hardly occurs even after the above.

[0012]

The present invention provides a recording sheet comprising a support and a coloring material receiving layer provided thereon, wherein the coloring material receiving layer is a layer comprising inorganic fine particles and a water-soluble resin. The water-soluble resin has an ethylene unit as a repeating unit in a molar ratio of 1 to 20% and a saponification degree of 85%.
A recording sheet characterized by being the above-mentioned modified polyvinyl alcohol.

The preferred embodiments of the recording sheet of the present invention are as follows. 1) The saponification degree of the modified polyvinyl alcohol is 95% or more (preferably 97 to 99.9%). 2) The modified polyvinyl alcohol contains 1 to 15% (preferably 3 to 1) of ethylene units as a repeating unit in a molar ratio.
3%). 3) The inorganic fine particles are silica fine particles (preferably anhydrous silica fine particles). 4) The inorganic fine particles are silica fine particles having an average primary particle diameter of 10 nm or less. 5) The weight ratio of the inorganic fine particles to the water-soluble resin is 1.5: 1 to 1
It is in the range of 0: 1. 6) The colorant receiving layer is a layer having many voids. 7) The colorant receiving layer has a porosity of 50% or more. 8) The colorant receiving layer has a light transmittance of 70% or more. 9) The degree of polymerization of the modified polyvinyl alcohol is 200 to 3
000 (preferably 300 to 2000). 10) The support is a transparent support. 11) The support is an opaque support whose surface has a glossiness of 70% or more. 12) The color material receiving layer has a layer thickness of 10 to 50 μm and is for inkjet recording. 13) The colorant receiving layer has a layer thickness of 0.1 to 10 μm and is for electrophotography or heat-sensitive recording.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The recording sheet of the present invention has a basic structure comprising a support and a coloring material receiving layer formed on the support. The color material receiving layer may be formed on only one surface of the support, or may be formed on both surfaces. Generally, a colorant receiving layer is formed on one surface of an inkjet sheet and both surfaces of an electrophotographic sheet.

The recording sheet of the present invention can be manufactured, for example, as follows. As a material that can be used as the support, it is preferable to use a transparent material having a property of withstanding radiant heat when used in an OHP or backlight display, but an opaque support such as paper may be used. As a material for the transparent support,
Examples thereof include polyesters such as polyethylene phthalate; cellulose esters such as nitrocellulose, cellulose acetate and cellulose acetate butyrate, and polysulfone, polyphenylene oxide, polyimide, polycarbonate and polyamide. Of these, polyethylene phthalate is preferred. The thickness of the support is not particularly limited, but a thickness of 50 to 200 μm is preferred because it is easy to handle. Further, the support may be subjected to corona discharge treatment, flame treatment or ultraviolet irradiation treatment.

As the support of the present invention, it is also possible to use a sheet which is opaque and has a glossiness of 70% or more on the surface on which at least the colorant receiving layer is provided. Examples of such a support include, for example, art paper, coated paper, cast coated paper, high gloss paper such as baryta paper used for silver salt photographic support, polyester such as polyethylene terephthalate (PET). , Cellulose esters such as nitrocellulose, cellulose acetate and cellulose acetate butyrate, and plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, etc. A film (having been subjected to surface calendering or the like), or a film in which a polyolefin coating layer containing or not containing a white pigment is provided on the surface of the paper, the transparent plastic film or the plastic containing the white pigment, etc. It can gel. The above baryta paper, polyolefin coated paper (a kind of support provided with a coating layer of polyolefin) or special paper provided with a metal vapor deposition layer, etc., which is used as a silver salt photographic support, is used in the present invention. It can be used preferably.

The color material receiving layer of the present invention can be manufactured, for example, as follows. The colorant receiving layer of the present invention,
It is mainly composed of the following novel modified polyvinyl alcohol and inorganic fine particles. The novel modified polyvinyl alcohol used as the binder of the colorant-receiving layer of the present invention is a modified polyvinyl alcohol having a repeating unit of 1 to 20% of ethylene units in a molar ratio and a saponification degree of 85% or more. The saponification degree of the modified polyvinyl alcohol is preferably 95% or more, and particularly preferably 97 to 99.9%. The higher the value, the better the water resistance, which is preferable. The modified polyvinyl alcohol preferably has an ethylene unit as a repeating unit in a molar ratio of 1 to 15%, particularly preferably 3 to 13%. Generally, it is preferable to have a high proportion of ethylene units, but if it is too high, the ink absorption rate will decrease. The degree of polymerization of the modified polyvinyl alcohol is preferably 200 to 3000, and particularly preferably 300 to 2000. The above-mentioned modified polyvinyl alcohol has improved water resistance without lowering the high ink absorption rate, excellent ink retention, and high dispersibility of inorganic fine particles that are exhibited by unmodified ordinary polyvinyl alcohol. A recording sheet having a coloring material receiving layer formed by using polyvinyl alcohol can form a good image by inkjet recording or the like even after being stored at high temperature and high humidity or after being stored for a long time.

Since the modified polyvinyl alcohol of the present invention is obtained by saponifying an ethylene / vinyl acetate copolymer, its structure generally has the following repeating units (1), (2) and (3): --CH. _{(OH) CH 2 - ··· (} 1) -CH (OCOCH 3) CH 2 - ··· (2) -CH 2 CH 2 - ··· (3) in a molar ratio of 68: 12: 20 99: 0: 1
It can also be expressed as having in the range of ((1) :( 2) :( 3)). That is, when the degree of saponification is close to 100%, the repeating unit derived from vinyl acetate in (2) above is close to zero.

The desired modified polyvinyl alcohol can be obtained by saponifying an ethylene / vinyl acetate copolymer having an ethylene content corresponding to the modified polyvinyl alcohol to a desired saponification degree by a known method.

If desired, a known water-soluble resin may be used together with the modified polyvinyl alcohol of the present invention as a binder. Examples of the water-soluble resin include polyvinyl alcohol (PVA), cellulosic resin (methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (as a resin having a hydroxyl group as a hydrophilic structural unit). CMC) etc.), chitins and starch; polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG) and polyvinyl ether (PVE) as a resin having an ether bond; and an amide group or an amide bond The resin may include polyacrylamide (PAAM) and polyvinylpyrrolidone (PVP). Further, a polyacrylate having a carboxyl group as a dissociable group, a maleic acid resin, an alginate and gelatins; a polystyrene sulfonate having a sulfone group, an amino group, an imino group, a tertiary amine and a quaternary ammonium salt. Having polyallylamine (PAA), polyethyleneimine (PEI), epoxidized polyamide (EPA
m), polyvinyl pyridine and gelatins.

The above-mentioned modified polyvinyl alcohol may be crosslinked with a crosslinking agent in order to improve the water resistance of the colorant receiving layer. That is, a cross-linking agent is added to a coating solution containing the above-mentioned modified polyvinyl alcohol and cross-linked polymer fine particles, the cross-linking agent is applied to a support, and dried by heating (cross-linking).
As a result, the color material receiving layer can be formed. Examples of the crosslinking agent include aldehydes (eg, formaldehyde, glyoxal, and glutaraldehyde),
N-methylol compounds (eg, dimethylol urea and methylol dimethylhydantoin), dioxane derivatives (eg, 2,3-dihydroxydioxane), compounds that act by activating carboxyl groups (eg, carbenium, 2-naphthalene sulfonate, 1,1-bispyrrolidino-1-chloropyridinium and 1-morpholinocarbonyl-3- (sulfonatoaminomethyl)), active vinyl compounds (eg, 1,3,5-triacroyl-hexahydro-s-triazine, bis (vinylsulfone) )
Methane and N, N′-methylenebis- [β- (vinylsulfonyl) propionamide]), active halogen compounds (eg 2,4-dichloro-6-hydroxy-S-triazine), isoxazoles, melamine resins, isocyanates Compounds and dialdehyde starch, etc. may be mentioned. These can be used alone or in combination. In consideration of productivity, it is preferable to use an aldehyde such as glutaraldehyde having a high reaction activity or a melamine resin. The addition amount of the crosslinking agent is preferably 0.1 to 20% by weight, and particularly preferably 0.5 to 15% by weight, based on the modified polyvinyl alcohol.

Examples of the inorganic fine particles include silica fine particles, colloidal silica, calcium silicate, zeolite,
Kaolinite, halloysite, muscovite, talc, calcium carbonate, calcium sulfate, boehmite and the like can be mentioned. For applications such as OHP where importance is attached to transparency, it is preferable to use one having a refractive index of 1.40 to 1.60 from the viewpoint of not impairing transparency. The average particle diameter of the inorganic fine particles is generally 0.1 μm or less. Of these, silica fine particles are preferable, and silica fine particles having an average primary particle diameter of 10 nm or less (preferably 3 to 10 nm) and a refractive index of 1.45 are preferable.

The silica particles have silanol groups on the surface.
Since particles are easily attached to each other by hydrogen bonding,
The average primary particle diameter is 10 nm or less (preferably 3 to 10 n).
m), the structure with large porosity (ink absorbency)
Can lead to the improvement of). silica
The particles are roughly classified into a wet method and a dry method depending on the manufacturing method. Wet
The method produces activated silica by metathesis of silicates, which
The method of obtaining water-containing silica by appropriately polymerizing and coagulating and precipitating
Mainstream. On the other hand, dry-process silica is made of silicon halide.
High temperature gas phase hydrolysis method (flame hydrolysis method)
Reductive vaporization of sand and coke by arc in an electric furnace
And oxidize this with air (arc method)
The method of obtaining mosquitoes is the mainstream. These hydrous silica and
Hydrosilica has a high density of surface silanol groups,
Although there are differences and show different properties, silicic acid anhydride (anhydrous silicic acid
In case of (f), it is easy to form a three-dimensional structure with a particularly high porosity.
preferable. The reason for this is not clear, but silanol on the surface
5-8 / nm when the density of the group is hydrous silica ^TwoAnd many
Particles tend to aggregate tightly (aggregate).
2-3 pieces / nm for Rica^TwoCoarse soft agglomeration
(Flocculate) and the structure has a high porosity.
Is determined.

As the inorganic fine particles, the average primary particle diameter is 1
When anhydrous silica having a particle size of 0 nm or less is used, it is considered that the hydroxyl groups of PVA and the silanol groups on the surface of the silica particles form hydrogen bonds to facilitate the formation of a three-dimensional network structure having secondary particles of silica particles as chain units. . It is considered that this makes it possible to obtain a colorant receiving layer having a structure with a high porosity. The colorant-receiving layer thus obtained not only enables ink-jet recording to rapidly absorb ink due to a capillary phenomenon and enables fine recording without ink smearing or ink accumulation, but also as a colorant in thermal recording, and electronic recording. The toner for photographic recording can be firmly adhered. The reason for this is
This is because the coloring material and the toner penetrate into the pores of the porous layer, and as a result, the coloring material and the like are firmly fixed by the shape anchoring effect resulting from the three-dimensional network structure. Further, since the proportion of the inorganic fine particles is large, it is characterized by high heat resistance and high emboss resistance in electrophotographic recording.

The ratio of the inorganic fine particles (preferably silica fine particles) to the modified polyvinyl alcohol (modified PVA) of the present invention (PB ratio: the weight of the inorganic fine particles to the weight 1 of the modified PVA) has a great influence on the film structure. The larger the PB ratio, the larger the porosity, the pore volume, and the surface area (per unit weight). If it exceeds 10, there is no effect on the film strength and cracking during drying, and if it is less than 1.5, the voids are blocked by the resin, the void ratio is reduced and the ink absorbing performance is deteriorated.
Therefore, the PB ratio is preferably in the range of 1.5 to 10. In particular, it is necessary to obtain sufficient film strength when directly touching with an hand like an OHP film, and a PB ratio of 5 or less is particularly preferable. Further, a PB ratio of 2 or more is required to obtain high-speed ink absorption in an inkjet printer. Particularly preferred, therefore P
The B ratio is more preferably in the range of 2 to 5.

For example, the average primary particle diameter as described above is 1
PB ratio of anhydrous silica of 0 nm or less and modified PVA of 2 to 5
When it is completely dispersed in an aqueous solution and coated and dried, a three-dimensional network structure having secondary particles of silica particles as chain units is formed, the average pore size is 30 nm or less, the porosity is 50% or more, and the pore specific volume is 0.5 ml / g or more, specific surface area 100 m ² / g
The above translucent porous film (colorant receiving layer) can be easily formed.

The colorant-receptive layer of the present invention comprises a coating material for forming a colorant-receptive layer obtained by dispersing the above-mentioned inorganic fine particles in a solution of a modified PVA in which a solvent having water as a main component is dissolved. It can be formed by applying and drying.

In the case of ink jet recording, the layer thickness of the colorant receiving layer needs to have an absorption capacity enough to absorb all the droplets, and this must be determined in relation to the porosity of the coating film. For example, when the ink amount is 8 nl / mm ² and the porosity is 60%, a film of about 15 μm or more is required.
In the case of inkjet recording, the range of 10 to 50 μm is preferable. In the case of thermal transfer or electrophotographic method, a coloring material or toner is adsorbed on the surface, so a thin film is sufficient, and 0.1 to 10 μm is preferable.

The inorganic fine particles and the modified PVA mainly constituting the colorant receiving layer may each be a single material or a mixture of a plurality of materials. The colorant receiving layer is mainly composed of the above-mentioned inorganic fine particles and modified PVA, but may further contain various inorganic salts in order to enhance the dispersibility of the particles, and acids and alkalis as PH adjusters. In addition, various surfactants may be used for the purpose of improving coating suitability and surface quality. In order to suppress frictional electrification and peeling electrification on the surface, or to adjust surface electric resistance in electrophotography, even if it contains a surfactant having ionic conductivity or metal oxide fine particles having electronic conductivity Good. Further, a mordant may be used for the purpose of fixing a dye and increasing water resistance in ink jet recording. Further, various matting agents may be included for the purpose of reducing the friction characteristics of the surface. Further, various antioxidants and ultraviolet absorbers may be contained for the purpose of suppressing the deterioration of the coloring material.

Further, an undercoat layer may be provided between the color material receiving layer and the transparent support for the purpose of enhancing the adhesiveness or adjusting the electric resistance. Further, the colorant receiving layer may be provided on one side of the transparent support, or may be provided on both sides in order to suppress curling. Further, when the color material receiving layer is provided on only one surface, an antireflection film may be provided on the opposite surface in order to enhance light transmittance.

The colorant receiving layer of the present invention can be provided on a support as follows, for example. The coating liquid for forming the colorant receiving layer is obtained by adding silica fine particles having an average primary particle diameter of 10 nm or less to water (eg, 10 to 15% by weight) to prepare a high-speed rotating wet colloid mill (eg, CLEARMIX (M Technique). (Manufactured by K.K.)), for example, 10,000 rp
After dispersing for 20 minutes (preferably 10 to 30 minutes) under the condition of high-speed rotation of m (preferably 5000 to 20000 rpm), a modified polyvinyl alcohol aqueous solution (eg, modified PVA having a weight of about 1/3 of silica is obtained). It can be obtained by further adding () to and further dispersing under the same conditions as above. The coating liquid thus obtained is a uniform sol, and by forming this on a support by the coating method described below, the colorant-receiving layer having a three-dimensional network structure of the present invention can be obtained. it can. That is, by coating the coating solution of the uniform sol on a support and then drying,
The solvent water is evaporated. By this evaporation, a wet gel is formed at the time when the coating film reaches the gelation concentration, and further drying progresses to form a porous xerogel, whereby a colorant receiving layer can be obtained.

The formation of the color material receiving layer is carried out, for example, by applying a coating solution obtained by further adding an antistatic agent or the like to the coating solution on the support (film) and heating and drying. can do. The coating can be performed by a known coating method such as an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, and a bar coater. Drying is generally performed at 50 to 180 ° C. for 0.5 to 30 minutes. Using a hot air dryer at a relatively low temperature (preferably 50 to 90 ° C (wind speed 3 to 8 m /
Second)) for 0.5 to 3 minutes, and then at a relatively high temperature (preferably 120 to 180 ° C. for 5 to 20 minutes). It is preferable from the viewpoint of preventing cracks when the receiving layer is dried.

After coating and drying, it is possible to improve surface smoothness, transparency and coating strength by passing between roll nip under heating and pressurization with, for example, a super calender or gloss calender. However, since such a treatment lowers the porosity (that is, the ink absorbency lowers), it is necessary to set conditions under which the reduction in the porosity is small.

[0034]

【Example】

[Example 1] <Preparation of coating liquid for forming colorant receiving layer (layer of modified PVA and inorganic fine particles)> Dry silica fine particles (average primary particle diameter: 7 nm; 10 parts by weight Refractive index: 1.45) Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.) 3.3 parts by weight of modified polyvinyl alcohol (ethylene unit: 10 mol%, saponification degree: 98.8%; degree of polymerization: 590, RS-106 (manufactured by Kuraray Co., Ltd.) )) Deionized water 136 parts by weight

The dry silica fine particles were mixed with ion-exchanged water (7
3.3 parts by weight), and using a high-speed rotary wet colloid mill (Clearmix (M Technique Co., Ltd.)) to disperse the mixture at 10,000 rpm for 20 minutes, and then add a modified polyvinyl alcohol aqueous solution (ion (Dissolved in the remaining 62.7 parts by weight of exchanged water) and further dispersed under the same conditions as described above, the pH was adjusted to 9.2 with aqueous ammonia, and the coating liquid for forming the colorant receiving layer was obtained. Got

The above coating solution was applied to the surface of a biaxially stretched polyethylene terephthalate film having a thickness of 100 μm, which had been corona-discharge treated on both sides, using an air knife coater, and dried with a hot air dryer at 70 ° C. (air velocity 5 m / sec. )
After drying for 1 minute at 100 ° C., it was further dried at 100 ° C. for 10 minutes. As a result, a color material receiving layer having a dry film thickness of 30 μm was formed. Thus, an inkjet recording sheet was obtained.

[Example 2] RS-117H (manufactured by Kuraray Co., Ltd., ethylene unit: 5 mol%, degree of saponification) was used as the modified polyvinyl alcohol used in the preparation of the coating liquid for forming the colorant receiving layer in Example 1. : 99.7%, degree of polymerization 165
An ink jet recording sheet was produced in the same manner as in Example 1 except that the same amount of (0) was used.

[Example 3] RS-117 (manufactured by Kuraray Co., Ltd., ethylene unit: 5 mol%, saponification degree) was used as the modified polyvinyl alcohol used in the preparation of the coating liquid for forming the colorant receiving layer in Example 1. : 98.5%; degree of polymerization 165
An ink jet recording sheet was produced in the same manner as in Example 1 except that the same amount of (0) was used.

[Example 4] RS-110 (manufactured by Kuraray Co., Ltd., ethylene unit: 5 mol%, saponification degree) was used as the modified polyvinyl alcohol used in the preparation of the coating liquid for forming the colorant receiving layer in Example 1. : 98.8%, degree of polymerization: 97
An ink jet recording sheet was produced in the same manner as in Example 1 except that the same amount of (0) was used.

[Comparative Example 1] In Example 1, instead of the modified polyvinyl alcohol used in the preparation of the coating liquid for forming the colorant receiving layer, ordinary unmodified polyvinyl alcohol (saponification degree: 88%, degree of polymerization: : 3500, PVA
An ink jet recording sheet was produced in the same manner as in Example 1 except that the same amount of 235 (manufactured by Kuraray Co., Ltd.) was used.

The ink jet recording sheet thus obtained was evaluated for ink jet suitability by the following measuring method. The following measurements were performed under two conditions, that is, the recording sheet was left in an atmosphere of 23 ° C. and 65% RH for 1 week, and left in an atmosphere of 40 ° C. and 85% RH for 1 week. 1) Ink absorption speed With an inkjet printer (PIXEL JET; manufactured by Canon Inc.), the paper is contact-pressed immediately after solid black printing on the recording sheet (after about 10 seconds), and the ink is transferred to the paper. It was judged as follows. AA: No ink was transferred to the paper. CC: Ink was transferred to the paper. 2) Ink Absorption Unevenness Using the same printer as described above, it was judged by the degree of ink absorption unevenness (unevenness in ink density) at the boundary of the solid black print portion printed on the recording sheet. AA: There was no uneven absorption. BB: Some uneven absorption was observed. CC: Absorption unevenness was considerably observed. 3) Parallel light transmittance haze meter (HGM-2DP; Suga Test Instruments Co., Ltd.)
Was used to measure the parallel light transmittance.

Further, the porosity of the colorant receiving layer obtained in the obtained example was measured as follows. Mercury porosimeter (Poresizer 9320-PC2; Shimadzu Corporation)
Manufactured) to obtain a distribution of porosity and calculate the average value thereof. The results of the above evaluations are shown in Table 1 below.

[0044]

[Table 1] Table 1 ──────────────────────────────────── Void <23 ℃, 65% RH ＞ <40 ℃, 85% RH> Rate Ink Ink Transmittance Ink Ink Transmittance (%) Absorption rate Absorption unevenness (%) Absorption rate Absorption unevenness (%) ──────────────── ───────────────────── Example 1 61 AA AA 79 AA AA 80 Example 2 62 AA AA 80 AA AA 81 Example 3 60 AA AA 81 AA AA 81 Example 4 60 AA AA 80 AA AA 80 ──────────────────────────────────── Comparative Example 1 63 AA AA 81 CC CC 81 ─────────────────────────────────────

[0045]

INDUSTRIAL APPLICABILITY The recording sheet of the present invention is capable of quickly absorbing a liquid ink in ink jet recording, without uneven absorption, and obtaining a fine image without ink bleeding or ink accumulation. Further, the recording sheet of the present invention,
Even after being left under high temperature and high humidity, there is almost no decrease in ink absorption speed or occurrence of ink absorption unevenness.
The colorant receiving layer of the present invention is a porous layer composed of a novel ethylene-modified PVA and inorganic fine particles, and the water resistance is improved without changing the porous structure obtained in the case of PVA which is not modified in general. ing. Therefore, it is considered that a sheet excellent in durability can be obtained without deteriorating the inkjet recording characteristics. Further, since it is excellent in ink absorption and bleeding prevention, the adhesiveness of the coloring material or toner is improved even in thermal transfer recording and electrophotographic recording. Therefore, it can be said that the recording sheet of the present invention is a recording sheet suitable for various recording methods.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 7/00 D21H 1/34 G

Claims (6)

[Claims] 1. A recording sheet comprising a support and a coloring material receiving layer provided on the support, wherein the coloring material receiving layer is a layer comprising inorganic fine particles and a water-soluble resin, and the water-soluble resin is
1-20% ethylene unit as a repeating unit in molar ratio
A recording sheet characterized by being a modified polyvinyl alcohol having a saponification degree of 85% or more within the range. 2. The saponification degree of the modified polyvinyl alcohol is
The recording sheet according to claim 1, which is 95% or more. 3. The recording sheet according to claim 1, wherein the modified polyvinyl alcohol has an ethylene unit as a repeating unit in a molar ratio of 1 to 15%. 4. The recording sheet according to claim 1, wherein the inorganic fine particles are silica fine particles. 5. The inorganic fine particles have an average primary particle diameter of 10 nm.
The recording sheet according to claim 1, which is the following silica fine particles. 6. The weight ratio of the inorganic fine particles to the water-soluble resin is 1.
The recording sheet according to claim 1, which is in the range of 5: 1 to 10: 1.