JPH0564993A - Recording sheet - Google Patents

Abstract

PURPOSE:To provide a recording sheet having the good adhesion to hot-melt ink, capable of preventing the unnecessary transfer to a sheet to be recorded, capable of easily forming a desired hot-melt ink layer and capable of applying accurate and sharp copy recording to the sheet to be recorded. CONSTITUTION:A receiving layer is provided to one surface of a film support and a porous layer is provided to the other surface thereof and a hot-melt ink layer is further provided on the porous layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet, and more particularly to a recording sheet suitable for use as a slip such as a single form or a continuous form.

[0002]

2. Description of the Related Art Recording sheets are used for various purposes. For example, in a copy-type voucher, a recording sheet and a recording sheet (usually made of paper) are stacked and the front side of the recording sheet is used. Type pressure applied to (receptive layer side),
A necessary amount of ink is transferred in the form of characters or figures onto the recording sheet from the ink layer provided on the back side of the recording sheet by writing pressure, heat, or the like. Hot melt ink is often used as the ink. When the base material (support) of such a recording sheet is made of paper, the hot melt ink penetrates well from the paper surface to an appropriate depth, and a desired hot melt ink layer is relatively easily formed.

However, for example, in a transportation slip such as a courier service, since the recording sheet located on the surface of the slip is required to have durability and weather resistance, recording using a plastic film, which is stronger than paper, as a support. Sheets are being used. However, while the film support is excellent in durability and weather resistance, the hot melt ink does not penetrate well as it is, and it is difficult to form a desired hot melt ink layer. Therefore, various ideas have been conventionally made for forming a hot melt ink layer on a film support. A conventional recording sheet having a film as a support usually has a layer structure of receiving layer / film support / hot melt ink receiving layer / hot melt ink layer. This hot-melt ink receiving layer is provided so that the hot-melt ink properly permeates and a desired hot-melt ink layer is formed on the surface of the hot-melt ink properly. Or
It is formed by coating the polymer resin containing a roughening substance. Also known is a method of improving the adhesion of the hot melt ink by roughening the surface of the film support itself by sandblasting or the like, or by subjecting it to corona discharge treatment or the like.

[0004]

However, the above-mentioned conventional recording sheet has a problem that the adhesion of the hot melt ink is not sufficient. for that reason,
Particularly when the handling is rough, the hot melt ink may be unnecessarily transferred to the paper as the recording sheet and stain the paper. Further, since the adhesion of the hot melt ink is not high, it is difficult to uniformly form an ink layer having a target thickness, and copy recording on a recording sheet may become unclear.

The present invention solves the above problems,
Adhesion of hot melt ink is good, unnecessary transfer to the recording sheet can be prevented, and the desired hot melt ink layer can be easily formed, allowing accurate and clear copy recording on the recording sheet. The purpose is to provide a stable recording sheet.

[0006]

The recording sheet of the present invention for this purpose is provided with a receiving layer on one side of a film support and a porous layer on the other side, and a hot mail is provided on the porous layer. It consists of an ink layer.

The material of the film support of the present invention is not particularly limited, and various known plastic films can be used. Typical examples include polyester film (including paper-like polyester film), polycarbonate film, triacetylcellulose film, cellophane film, polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyethersulfone film, aromatic. Examples thereof include polyamide film, polysulfone film, polyolefin film and the like. However, it is preferable to use a polyester film, a polycarbonate film, or a polyphenylene sulfide film in view of mechanical properties, thermal properties, cost, and the like, and the polyester film is particularly preferable.

Polyester film is a general term for polymer films having an ester bond as a main connecting chain, and particularly preferable polyesters are polyethylene terephthalate, polyethylene 2,6-naphthalate, polyethylene α, β-bis (2 -Chlorophenoxy) ethane 4,4'-dicarboxylate, polybutylene terephthalate, etc. Among them, polyethylene terephthalate (hereinafter sometimes abbreviated as PET) in view of quality, economy and the like. Is most preferred. In addition, known additives in the PET, for example, heat resistance stabilizer, oxidation resistance stabilizer, weather resistance stabilizer, ultraviolet absorber,
Organic lubricants, pigments, dyes, organic or inorganic fine particles,
You may mix | blend a filler, a mold release agent, an antistatic agent, a nucleating agent, etc.

The PET film is unoriented, uniaxially oriented,
Although biaxially oriented PET film can be used, a biaxially oriented PET film is preferable because of its excellent mechanical strength. The biaxially oriented PET film is produced by stretching a PET sheet or film in an unstretched state by a factor of 2.5 to 5 in the so-called biaxial directions of the longitudinal direction and the width direction. It refers to those showing a pattern of orientation.

In the case of a PET film which has been subjected to surface treatment by a known method, that is, corona discharge treatment (in air, nitrogen, carbon dioxide gas, etc.) or an easy-adhesion treatment, the adhesion with the porous layer is improved. Since it has improved water resistance, solvent resistance and the like, it can be used more preferably. For the easy-adhesion treatment, various known methods can be used, and various types of easy-adhesives such as acrylic, urethane, and polyester adhesives applied in the film manufacturing process, or the above-mentioned film after uniaxial or biaxial stretching are used. Those coated with various types of easy-adhesives such as can be suitably used.

The thickness of the plastic film as the film support is not particularly limited, and can be set to an appropriate thickness within the range of about 1 to 500 μm, for example, in consideration of the stiffness of the recording sheet.

The surface roughness and haze of the film support are not particularly limited, and the thickness of the porous layer described below, the adhesive strength required between the porous layer and the film support, recording, It may be appropriately set to a desired value in consideration of the transparency and whiteness required for the sheet.

In the recording sheet of the present invention, a porous layer is provided on the surface of the film support opposite to the receiving layer. The porous layer referred to in the present invention has a layer structure having a large number of voids inside and on the surface of the layer. It is particularly preferable that these voids are so-called through-holes that communicate with the outside in the porous layer from the viewpoint of appropriate penetrability of the hot-melt ink described below (that can secure good adhesion).

In the present invention, the peak pore size in the pore size distribution curve of the pores of the porous layer is 0.06 to 2.0 μm, preferably 0.08 to 1.0 μm, more preferably 0.10.
Is 0.5 μm. The peak pore size of the pore size distribution curve is 0.
If it is less than 06 μm, the ink absorption will be insufficient,
When the peak pore diameter in the pore diameter distribution curve exceeds 2.0 μm, the surface smoothness is lowered, and the sharpness of copy recording with ink tends to be insufficient.

The pore area ratio is preferably 20 to 85%, preferably 30 to 75%, and more preferably 35 to 65%. When the pore area ratio is less than 20%, the ink absorption amount is insufficient. When it exceeds 85%, the holes are likely to be partially connected, the amount of ink becomes excessive, the cost increases, and the copy recording becomes unclear.

When viewed from the surface of the porous layer, the pores are independent of each other, and their roundness r (= b / a,
It is particularly preferable that (a: major axis diameter of pores, b: minor axis diameter of pores) be 1 to 5 because ink absorption is uniform over the entire surface and there is no unevenness in density. This roundness is an average value of 1000 or more measurement points and is usually obtained by an image analyzer.

Further, it is desirable that the spread of the pore size distribution in the pore size distribution curve is smaller, that is, the pore size distribution is sharper, and is 50% or more, preferably 60% or more of the number of holes.
More preferably, 70% or more is preferably within the peak pore size ± 30%.

Next, when the center line average roughness of the porous layer in the present invention is 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.1 μm or less, the sharpness of copy recording is improved, which is preferable. .. If it exceeds 0.5 μm, copy recording tends to become unclear.

The surface of the porous layer in the present invention has a waviness of 0.2 μm or more, preferably 0.3 μm or more, more preferably 0.4 μm or more, 5/40 μm or more, preferably 7 / waviness. 40 μm or more, more preferably 1
It is desirable to have 0/40 μm or more. Height is 0.
If the number of wavinesses of 2 μm or more is less than 5/40 μm, the ink absorption speed becomes insufficient and the workability deteriorates.
In addition, insufficient ink absorption is likely to occur.

Furthermore, the waviness index of the surface of the porous layer is 0.0.
35-0.3 μm, preferably 0.045-0.2 μ
m, more preferably 0.055 to 0.13,
It is preferable because the absorption rate of the ink is improved.

A hot melt ink layer is provided on the porous layer. Hot-melt ink is heated and melted or heated to a certain temperature on the printing machine until the moment when it is printed and applied to the material to be printed, maintaining printability such as fluidity, and after printing it is cooled or printed at room temperature. The hot-melt ink used for the recording sheet of the present invention is not particularly limited as long as it forms a strong coating film on the material, and known heating type carbon ink for copying, transfer type thermal ink, hot-melt type glass. Ink or the like can be used. In the case of slips, carbon ink is suitable, in the case of transfer recording with a thermal head in a computer or a personal computer, transfer type thermal ink is suitable, and in the case of transfer to a glass surface, hot melt type glass ink is suitable.

The receptive layer of the present invention is a layer composed of a composition containing a white hidden pay pigment and a polymer resin binder as main components. The layer containing the main component means that the content of the layer is 50% by weight or more in the receiving layer, and other substances may be added as appropriate. In the present invention, such a receiving layer is provided on one surface of the film support.

The polymeric resin binder referred to in the present invention is
A resin that is selected from thermoplastic resins and thermosetting resins, and is a resin that is soluble in well-known organic solvents and that has a small amount of hydrophilic groups or hydrophilic components is preferable in terms of water resistance and moisture resistance of the receiving layer, Specific examples include acrylics, vinyls, urethanes, epoxies, polyesters, polypropylenes, melamines, carbonates, butyral, and the like, and copolymers and mixtures thereof.

In the present invention, the water resistance and solvent resistance of the receiving layer,
From the viewpoint of heat resistance, abrasion resistance, mechanical strength, etc., thermosetting resins are preferably used, and those which can be crosslinked by using a well-known crosslinking agent are more preferable. Examples of the organic solvent include alcohol-based, carboxylic acid ester-based, ketone-based, aliphatic hydrocarbon, alicyclic or aromatic hydrocarbon-based solvents, and mixed systems thereof, which do not adversely affect coatability and the like. The choice of one is preferred.

The white hidden pay pigment in the present invention is an inorganic or organic pigment that presents a white receptive layer, and examples of the inorganic pigment include zinc carbonate, zinc oxide, zinc sulfide,
Talc, carion, heavy / light or synthetic calcium carbonate, titanium oxide, silica, lithium fluoride, calcium fluoride, barium sulfate, alumina, zirconia, calcium phosphate, natural or synthetic swelling or non-swelling mica, etc. Examples of the organic pigment include polystyrene, polymethylstyrene, polymethoxystyrene, polyvinyl chloride, polyethylene, polypropylene, polyvinylidene chloride, polymethacrylate, polymethylmethacrylate, polychloroacrylate, and the like. At least one selected from the above is applied, but is not particularly limited. Further, the pigment may be in a hollow porous state or a non-hollow porous state. Further, the pigment may be subjected to a treatment such as addition of a functional group such as glycidyl or methylol group to the surface thereof in order to improve dispersibility in the resin.

The average particle size of the white hidden pay pigment is 0.1 to 25.
It is preferable that the thickness is in the range of 1.0 μm, preferably 1.0 to 10 μm from the viewpoint of handleability and coatability. The content of the white hidden pay pigment in the receiving layer is preferably 0.1 to 70% by weight, more preferably 5 to 50% by weight. The content is 0.
If it is less than 1% by weight, the white concealing paying property is sufficient, and if it is 70% by weight or more, the adhesiveness between the receiving layer and the film substrate tends to be lowered.

In the present invention, the adhesion of the receiving layer, solvent resistance,
In order to further improve the heat resistance, it is preferable that the receiving layer contains a cross-linking agent.

The cross-linking agent in the present invention means a functional group present in the polymer resin binder, for example, a hydroxyl group,
There is no particular limitation as long as it is a cross-linking agent for cross-linking reaction with a carboxyl group, a glycidyl group, an amide group, etc. to finally form a receiving layer having a three-dimensional network structure, but typical examples are methylolated or alkylolated. Examples thereof include urea-based, melamine-based, acrylamide-based, polyamide-based resins, epoxy compounds, isocyanate compounds, and aziridine compounds.

These cross-linking agents may be used alone or in combination of two or more depending on the case. The amount of the cross-linking agent to be added is appropriately selected depending on the type of the cross-linking agent, but is usually preferably 0.01 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the solid content of the polymer resin. preferable. Further, it is more preferable to use a crosslinking catalyst together with the crosslinking agent because crosslinking will proceed further. As the cross-linking catalyst, known ones such as salts, inorganic substances, organic substances, acid substances and alkaline substances can be used. The amount of the crosslinking catalyst added is 0.001 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the solid content of the polymer resin. The polymer resin to which a cross-linking agent is added is applied to the film support and then cross-linked by heating, ultraviolet rays, electron beams or the like, but usually a method by heating is generally used.

The receiving layer constituting the recording sheet of the present invention is
The smoothness is 2 to 3000 seconds, preferably 10 to 150
The range of 0 seconds is desirable. If the smoothness is out of this range, for example, when printing is performed using a fabric ribbon, the ink permeability does not match, the printing becomes light, and the ink easily remains on the surface of the receiving layer, which is not preferable. In the present invention, the whiteness of the receptor layer is 40% or more,
It is preferably 60% or more. When the whiteness of the hunter is less than 40%, the hidden payability becomes insufficient, the resolution and sharpness of the type on the surface of the receiving layer are deteriorated, and a reading error such as in the case of a bar code is likely to occur, which is not preferable. The laminated thickness of the receiving layer is not particularly limited, but is preferably 0.5 to 50 μm and 1.0
The thickness in the range of up to 20 μm is desirable from the viewpoints of uniform forming property of the receiving layer and adhesiveness. Further, in the receiving layer, if necessary, known additives such as antifoaming agents, coatability improvers, thickeners, antistatic agents, ultraviolet absorbers, dyes, etc. are added in an amount that does not impair the effects of the present invention. May be included.

Next, the method for producing the recording sheet of the present invention will be explained, but the present invention is not necessarily limited to this.

First, the porous layer of the present invention is obtained by mixing a water-dispersible polymer and a specific colloidal silica in a specific range, coating the mixed solution, and drying. Here, the water-dispersible polymer may be an aqueous dispersion of various polymers, and specific examples thereof include acrylic polymers, ester polymers, urethane polymers, olefin polymers, vinylidene chloride polymers,
Aqueous dispersions of epoxy polymers, amide polymers, and modified products and copolymers thereof can be used. Acrylic polymers and urethane polymers are preferably used because the pore size distribution is sharp and the pore area is large, and acrylic polymers are particularly preferred from the viewpoint of mechanical stability of the coating film and coating strength.

The above-mentioned polymer used in the present invention is preferably dispersed in water and has a particle shape. When it does not have a particle shape, that is, when it is a water-soluble polymer or a polymer dissolved in an organic solvent, it is difficult to make it porous.
The particles are preferably dispersed with primary particles, but they are not necessarily dispersed with primary particles, and may include secondary aggregated particles.

Acrylic polymers suitable as the porous layer-forming polymer of the present invention are at least 40 mol% or more of acrylic monomers, and / or methacrylic monomers and their ester-forming monomers, acrylic monomers having various functional groups, such as acrylic. Acid, methacrylic acid,
Alkyl acrylate, alkyl methacrylate (as the alkyl group, a methyl group, an ethyl group, an n-propyl group,
Isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, etc.), and 2-hydroxyethyl acrylate, 2-
Hydroxy-containing monomers such as hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide,
Amide group-containing monomers such as methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolmethacrylamide, N-methylolacrylamide, N, N-dimethylolacrylamide, N-methoxymethylmethacrylamide, and N-phenylacrylamide , Amino group monomers such as N, N-diethylaminoethyl methacrylate and N, N-diethylaminoethyl acrylate, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, salts of acrylic acid and methacrylic acid (sodium salt, potassium salt, ammonium salt) Etc.) and the like, and these can be used in combination with various monomers. Examples of the various monomers include monomers containing epoxy group-containing monomers such as allyl glycidyl ether, sulfonic acid groups such as styrene sulfonic acid, vinyl sulfonic acid and their salts (sodium salt, potassium salt, ammonium salt, etc.) or salts thereof. , Monomers containing carboxyl groups such as crotonic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof, or salts thereof, maleic anhydride, monomers containing acid anhydrides such as itaconic anhydride, vinyl isocyanate, allyl isocyanate , Styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, salt Vinyl, vinyl acetate, vinylidene chloride and the like. The above-mentioned monomers are copolymerized by using one kind or two or more kinds.

Water dispersion 20 of the above water-dispersible polymer
As the colloidal silica mixed with 90 parts by weight, the following silica is preferable because it causes undulations in the porous layer. That is, one having a long-chain structure in which spherical colloidal silica is connected in a beaded shape (a shape in which a plurality of spherical colloidal silica are connected in a chain), and one in which the connected silica is branched and / or bent is used. In this case, a porous film having a waviness structure on the surface can be obtained. The colloidal silica is obtained by connecting primary particles of spherical silica with each other by interposing metal ions having a valence of 2 or more, and connecting the particles with each other. At least 3 or more, preferably 5 or more, and more preferably 7 or more are connected. Further, it also includes particles in which particles connected in a beaded shape are branched and / or bent.

Further, colloidal silica and other inorganic particles,
For example, it may be a composite or mixed particle of alumina, ceria, titania, etc., or may be a particle in which these particles are intervened and connected. The intervening metal ion is preferably a divalent or higher valent metal ion, for example, Ca ²⁺ , Zn ²⁺ , M
g ²⁺ , Ba ²⁺ , Al ³⁺ , Ti ⁴⁺ and the like. Especially Ca ²⁺
In this case, it is suitable for producing colloidal silica that is connected and branched in a beaded shape. The primary particle diameter of colloidal silica is 5 nm to 100 nm, preferably 7 nm to
When it is 50 nm, more preferably 8 nm to 30 nm, it is preferable in terms of increasing the pore forming property and the pore area ratio. Furthermore, the waviness of the porous layer develops when the silica particles are connected and branched in a beaded shape, and the larger the number of connected silica primary particles is, the more preferable, but usually 3 or more and less than 100, preferably 5 or more and less than 50, more preferably 7
It is desirable that the number is not less than 30 and not more than 30. When the number is 2 or less, the waviness is insufficiently expressed, and when the number is 100 or more, the content of the silica particles connected and / or branched in a beaded shape in the porous coating film is 3 to 80 parts by weight, preferably 10-7
The amount is 0 parts by weight, more preferably 20 to 60 parts by weight. If the content is less than 3 parts by weight, there is no porosity-forming property and no waviness is exhibited, so that the ink absorption rate tends to be slow. If it is contained in an amount of more than 80 parts by weight, the porosity is reduced, the pore size is reduced, the pore area ratio is reduced, the ink absorption rate is reduced, and the strength of the coating film is inferior. Defects such as dust are likely to occur.

The porosity depends on the ratio of the average particle size of the water-dispersible polymer to the colloidal silica, and the average particle size of the colloidal silica needs to be smaller than the average particle size of the water-dispersible polymer. It cannot be made porous. In the case of the above-mentioned bead-shaped colloidal silica, the length in the short axis direction of the connected particles observed by an electron microscope is taken as the particle diameter, and the average value of 100 measurement lengths is taken as the average particle diameter.

The average particle size ratio of water-dispersible polymer / colloidal silica is 2/1 to 1000/1, preferably 5/1.
It is particularly preferably from 500/1, more preferably from 10/1 to 200/1, from the viewpoint of forming the pores of the porous layer. In particular an average particle size ratio in relation to an average particle size of colloidal silica and (a ₁₎ and the average particle size of the water-dispersible polymer (a ₂₎ is in the above range, and complete one surface water-dispersible polymer particles The minimum number of particles of colloidal silica required for coating is α [α = 2π (a ₁ + a ₂ ) ² / (3 ^1/2 ·
when the a ₁ ^2)], water-dispersible polymer particles per range 0.3Arufa～10arufa, preferably 0.5α~6
When the blending ratio is set to α, more preferably 0.7α to 3α, the effect of the present invention is more significantly exhibited, which is preferable.

Any known method such as gravure coating, reverse coating, bar coating, kiss coating, or die coating can be used as the coating method.

The thickness of the porous layer is not particularly limited, but is usually 0.1 to 50 μm, preferably 1 to 30 μm, more preferably 3 to 20 μm. If the thickness is too thin, the absorption performance of the hot melt ink will be insufficient, and if it is too thick, the strength of the coating film will tend to be insufficient.

The hot-melt ink layer as described above is formed on the porous layer of the surface-porous film thus obtained, and the receiving layer as described above is provided on the surface on the anti-porous layer side. The method for forming the hot melt ink layer is not particularly limited, and a known method can be used.

[0042]

In the recording sheet of the present invention, the receiving layer is provided on one surface of the film support, the porous layer is provided on the other surface, and the hot melt ink layer is provided on the porous layer. As a result, the following excellent effects could be obtained.

First, since the recording sheet of the present invention is excellent in the adhesiveness and abrasion resistance of the hot melt ink layer, the hot melt ink layer can be easily formed in a desired layer, and the copied record is clear and easy to see.

Further, since the recording sheet of the present invention is excellent in the adhesiveness of the hot melt ink layer, it is excellent in the handling property in the post processing.

Further, the receiving layer of the recording sheet of the present invention comprises a fabric ribbon, electrophotographic toner, oil-based ink, U
Excellent printability with various inks such as V ink.

Since the recording sheet of the present invention has the excellent characteristics as described above, it can be applied to various applications in which copy recording is required, but among them, it can be used as a delivery slip for business use or courier service. It is suitable.

[Measurement and Evaluation Method] The characteristic values in the present invention are based on the following measurement methods and evaluation criteria. (1) Pore size distribution curve Marking the hole part of the electron microscope surface photograph taken at 10,000 times and performing image processing using a Quant: met-720 type image analyzer (manufactured by Image Analyzing Computer) to determine each hole size. When converted into a perfect circle, the area between the smallest and largest pores was divided into 10 μm units, and the number of pores in each divided portion was measured. From these measured values, a pore diameter distribution curve was drawn with the vertical axis representing the number of pores per unit area and the horizontal axis representing the pore diameter to determine the pore diameter at the peak.

(2) Pore area ratio From the above pore size distribution curve, the area occupied by pores per unit area was calculated by the following formula 1.

[0049]

[Equation 1]

In the above mathematical expression 1, what is indicated by each symbol is as follows. a _i : Average pore diameter in each divided portion when the pore diameter in the measurement area is divided by 10 mμ n _i : Number of pores in each divided portion when the pore diameter in the measurement area is divided by 10 m μ A: Measurement area

(3) Center Line Average Roughness Cutoff of 0. 0 according to JIS-B-0601-1976.
It was measured at 25 mm.

(4) Waviness height, number of waviness, waviness index Scanning electron microscope ESM-32 with cross-section measuring device PMS-1
No. 00 (manufactured by Elionix Co., Ltd.) was used to measure the unevenness of the surface observed at a magnification of 3000 times, and the valleys and valleys most adjacent to the peaks with a height of 0.2 μm or more from the surface roughness curve were measured. When the parts were connected by a straight line, the number of peaks in the measurement length of 40 μm was measured, and the number of waviness was 0.2 μm or more. Further, from the above surface roughness curve, a cutoff of 10
Centerline average roughness (Ra ₁₀ ) in μm, cutoff 1
The centerline average roughness (Ra ₁ ) in μm was obtained, and the waviness index was calculated by the following formula. Waviness index (μm) = Ra ₁₀ −Ra ₁ The waviness index and the waviness index were the average values of 50 measurement points.

(5) Average particle diameter The particle diameter was determined by a light scattering method using a laser using a COULTER, N4 type, submicron particle analyzer (manufactured by Nikkaki Co., Ltd.), and the average value of 10 measurements was taken. When the measurement cannot be performed by this method, it was determined from a 200,000 times electron micrograph.

(6) Average number of particles The average number of particles contained in 1 ml of an aqueous dispersion of V% by weight is calculated by the following formula 2 from the average particle size a determined above and the particle specific gravity ρ determined by the density gradient method. It was

[0055]

[Equation 2]

(7) Smoothness The smoothness was determined by measuring with an Oken type air permeability smoothness tester "Model KB15" (Asahi Seiko Co., Ltd.).

(8) Hunter whiteness L was measured using "Macbeth" 2000 manufactured by Kolmogen.
a and b were measured, and Hunter whiteness (W) was calculated by the following formula (measured at 550 nm). W = 100 [(100-L) ² + a ² + b ² ] ^1/2

(9) Recording property of receiving layer Serial printer "PC-PR20" manufactured by NEC Corporation
1U "and the character pattern is the fabric ribbon" O "
AR-NF-2 "(manufactured by Pilot Co., Ltd.) was used for printing, the print quality and the ink absorption were evaluated, and the recording property was judged as follows. The print quality was evaluated by visual observation and the ink absorption was evaluated. Immediately after printing, the character pattern was rubbed 5 times with a finger and rubbed back and forth, and evaluated by the degree of stain of the receiving layer with ink ◯: Both print quality and ink absorbability are good Δ: Print quality and ink absorbency are slightly inferior ×: Both print quality and ink absorption are poor

(10) Ink adhesion [I] Cellotape on the ink layer: CT-24 (Nichiban Co., Ltd.)
Manufactured) was adhered and pressed back and forth 5 times under a load of 2 kg using a hand roller, and then the cellophane tape was forcibly peeled in the 180 ° direction by hand, and the degree of peeling of the ink layer was observed and evaluated. Criteria were as follows: ◯: good (peeling area less than 5%), Δ: somewhat inferior (peeling area 5% or more and less than 20%), x: poor (peeling area 20% or more).

(11) Ink Adhesion [II] The ink layer was evaluated by a Gakushin type friction fastness test. The number of abrasions was set to 1 to 5 and the ink layer after abrasion was visually observed and judged as follows. Good adhesion: ○, slightly poor adhesion:
Δ, poor adhesion: ×.

[0061]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Example 1 Center line average roughness of 0.053 μm as a film support,
The following coating material was applied to one side of a biaxially stretched polyethylene terephthalate film having a whiteness of 93% and a thickness of 50 μm so that the thickness after drying was 10 μm, and dried at 130 ° C. for 2 minutes to obtain a porous film. The coated surface of the polyethylene terephthalate film was one that had been subjected to corona discharge treatment in air. [Coating material composition] Branched with 70 parts by weight of acrylic polymer emulsion (methyl methacrylate / ethyl acrylate / acrylic acid (60/35/5 wt%) copolymer) having an average particle diameter of 0.2 μm (solid content weight ratio) Bead-shaped colloidal silica (for example, Snowtex U manufactured by Nissan Chemical Industries, Ltd.)
P, average particle diameter 0.015 μm) 30 parts by weight (solid content weight ratio) was diluted with water to give a coating material of 30% by weight.

Next, toluene / ethyl acetate (mixing ratio: 1: 1) was used as a diluting solvent on the non-coated surface of the film, and a heat-crosslinking acrylic resin "Cotax" LH-613 was added thereto.
(Manufactured by Toray Industries, Inc.) and an average particle diameter of 1.
A uniform dispersion coating material having a concentration of 25% by weight, in which 40% by weight of titanium oxide of 0 μm was added, was applied to form a coating layer of 12
It was dried at 0 ° C. for 1 minute to provide a receptive layer having a thickness of 3.0 μm. The film thus obtained was set on a hot plate set at 125 ± 5 ° C., and hot melt ink “HTS66S” rubber convex black manufactured by Teikoku Ink Co., Ltd. was applied on the porous layer by a bar method to form an ink layer 5 A recording sheet having a thickness of 0.0 μm was produced. The properties of the recording sheet are as shown in Table 1, and the ink adhesion was excellent.

Comparative Examples 1 and 2 In the coating material for forming the porous layer of Example 1, spherical colloidal silica having an average particle diameter of 0.015 μm (Comparative Example 1) was used instead of the branched beaded colloidal silica, and an average particle diameter of 0. Two
A recording sheet was obtained in the same manner except that spherical colloidal silica having a diameter of μm (Comparative Example 2) was used. As shown in Table 1, Comparative Examples 1 and 2 were inferior in the ink adhesion of the recording sheet due to the insufficient properties of the porous layer.

Examples 2, 3 and Comparative Examples 3 and 4 In the coating material for forming the porous layer of Example 1, the average particle diameter and solid content of the acrylic polymer emulsion and the branched beaded colloidal silica were changed. A recording sheet was prepared in the same manner except for the above. When the porous layer is within the scope of the present invention (Examples 2 and 3), the ink adhesion is excellent,
Those not satisfying the scope of the present invention (Comparative Examples 3 and 4) were:
It can be seen that the ink adhesion is poor.

Example 4 Based on Example 1, the same polymeric resin binder as in Example 1 was used as the receiving layer, and the average particle size of 0.5 was used as the white hidden pay pigment.
30% by weight of titanium oxide with a solid content of 10 μm and 10% by weight of porous amorphous silica with an average particle size of 4.0 μm with respect to the solid content
Using the added uniform dispersion coating material having a concentration of 30% by weight, a recording sheet was obtained in the same manner as in Example 1 below. As shown in Table 1, the properties of the recording sheet were excellent in each property.

[0066]

[Table 1]

Claims (9)

[Claims] 1. A recording sheet comprising a receiving layer on one surface of a film support, a porous layer on the other surface, and a hot-melt ink layer on the porous layer. 2. The porous layer has a peak pore size in a pore size distribution curve of 0.06 to 2.0 μm, and the surface of the porous layer has 5 undulations having a height of 0.2 μm or more / 40 μm.
The recording sheet according to claim 1, which has the above. 3. The pore area ratio of the porous layer is 20 to 85%.
The recording sheet according to claim 1 or 2. 4. The waviness index of the surface of the porous layer is 0.0.
The recording sheet according to any one of claims 1 to 3, which has a thickness of 35 to 0.3 µm. 5. The recording sheet according to claim 1, wherein the center line average roughness of the surface of the porous layer is 0.5 μm or less. 6. The recording sheet according to claim 1, wherein the holes in the porous layer are through holes, and the circularity of the holes observed from the surface is in the range of 1 to 5. .. 7. The layer according to claim 1, wherein the porous layer is a layer containing a mixture of a water-dispersible polymer and colloidal silica having a bead-shaped connection and / or branch shape as a main component. Recording sheet. 8. The recording sheet according to claim 1, wherein the smoothness of the receiving layer is 2 to 3000 seconds. 9. The recording sheet according to claim 1, wherein the receptor whiteness of the receiving layer is 40% or more.