JPH0577515B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a recording sheet, and more particularly to a recording sheet that can be printed with a ballpoint pen, pencil, carbon transfer ink, printing ink, or the like. BACKGROUND ART Recording sheets are used in output devices such as electronic typewriters and printers, and the demand for them is increasing. Traditionally, this type of recording sheet has been made of plain paper,
Those using a paper base material such as coated paper, a matte film whose sheet surface is irregularly roughened, and those using a plastic base material such as synthetic paper are known. In order to improve the absorption and adhesion of printing ink, paper-based materials are strengthened by calendering during the paper manufacturing process to improve surface smoothness, or coated with a layer containing a large amount of talc, etc. Methods such as applying coating to improve ink absorption have been applied.
However, when paper-based recording sheets are used outdoors after printing, they may be exposed to rainwater, causing the print to smear or change color, eventually making it impossible to read satisfactorily. Not only that, but there is also the serious problem of loss of liver and kidney information due to damage, etc. Additionally, many paper-based recording sheets do not have sufficient transparency;
It is inconvenient that two sheets are used one on top of the other, making it impossible to streamline information reading, and that the same information must be printed on each sheet. On the other hand, with plastic base materials, the printing ink has poor absorption properties and hardly penetrates into the base material, so if the printed surface is rubbed, the prints become blurred or disappear. There is a problem. Furthermore, if fingerprints or finger oils adhere to the surface of the plastic-based sheet while handling it, there is a problem in that the adhesion of printing ink is reduced and writing performance, particularly with a ballpoint pen, is significantly deteriorated. Purpose of the Invention The purpose of the present invention is to solve the above-mentioned problems, to provide excellent printability especially when used as a recording sheet for a dot printer of a computer output device, and to provide long-lasting printability depending on the environment in which the recording sheet is used. ,durability,
Excellent stability, writing ability with ballpoint pens, pencils, magic ink, etc., and transferability with carbon ink.
The purpose of the present invention is to provide a recording sheet with excellent receptivity and sharpness of print. Structure/Effects of the Invention According to the present invention, an object of the present invention is, firstly, to provide a recording sheet in which a printing layer is provided on a plastic film, the surface of the printing layer being roughened with a large number of protrusions; And the relationship between the height of the protrusions and their number is the height (h) of the lower surface protrusions and the number h < 1.5 μm: 1500 to 3000 (pieces/mm ² ) h = 1.5 to 4.0 μm: 20000 to 35000 (pieces/mm 2 ) mm ² ) h>4.0 μm: 2000 to 4000 (pieces/mm ² ) This is achieved by a recording sheet. Polymers constituting the plastic film in the present invention include polyester, polyolefin, polyamide, polyesteramide, polyamideimide, polyimide, polystyrene, polycarbonate, poly-p-phenylene sulfide,
Preferred examples include polyether ester and polyvinyl chloride. Further examples include copolymers, blends, and crosslinked products of these. Among these, polyester is preferably used. The polyester referred to herein is a polyester containing an aromatic dicarboxylic acid as a main acid component and an alkylene glycol as a main glycol component. Preferred examples of these polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, and polyethylene-1,5-naphthalate. The plastic film used in the present invention is preferably stretched from the viewpoint of mechanical strength, dimensional stability, thermal properties, optical properties, etc. The thickness of the plastic film is preferably 5 μm to 250 μm, more preferably 15 μm to 150 μm. If it is thinner than this, it will lack mechanical strength as a base film and will be difficult to handle, while if it is thicker than this, the transportability of a recording sheet used in a printer or the like will deteriorate, which is not preferable. Furthermore, the plastic film may be subjected to known surface treatments, such as corona discharge treatment, plasma treatment, anchor coating treatment, etc., in order to improve adhesiveness, if necessary. Furthermore, if it is necessary to substantially reduce light transmittance and impart opacity to these plastic films, additives such as titanium oxide, silica, alumina, barium sulfate, calcium carbonate, and silicone may be added to the plastic film. It may be added or coated, or it may be vapor-deposited, chemically etched,
A film laminated with different polymer films may also be used. In the present invention, a printed layer is provided on a plastic film, and the surface of the printed layer is roughened with a large number of protrusions, and the relationship between the height of the protrusions and their number (protrusion number distribution) is the height of the lower surface protrusions ( h) and their number h<1.5μm: 1500-3000 (pieces/ ^mm2 ) h=1.5-4.0μm: 20000-35000 (pieces/ ^mm2 ) h>4.0μm: 2000-4000 (pieces/ ^mm2 ) need to be satisfied. This distribution of the number of protrusions is determined by imagining the uneven profile of the surface of the printing layer using a three-dimensional surface roughness meter, and cutting this profile into a section with a height of 0.25 μm in the direction perpendicular to the thickness direction of the printing layer. The total sum of the peaks of protrusions counted in one section is determined, and the proximity of the section that is 70% of the previous count is set as the reference level (0 level), and the protrusion peaks counted in the section at a certain height from this reference level are calculated. The number is calculated as the number (pieces/mm ² ) of the height of the protrusions (h: μm), and this is calculated as the number of protrusions with a height (h) of less than 1.5 μm,
The protrusions were divided into three categories: 1.5 to 4.0 μm and larger than 4.0 μm, and the number of protrusions distributed in each category was counted. Protrusions of less than 1.5 μm improve the compatibility with pens such as ballpoint pens and printer pens on the surface of the recording sheet.
Improves the transferability of carbon transfer ink, pressure sensitive ink, thermal transfer ink, etc. In addition, the 1.5 to 4.0 μm protrusions create a soft feel and texture on the mat surface that prevents pens from slipping, and make it suitable for use with pencils, magic inks, water-based inks, ink pads, etc. Furthermore, in the present invention, the distribution of protrusions larger than 4.0 μm is particularly important, as they provide absorption of fingerprint oils such as dot printer ink, ballpoint pen ink, carbon transfer ink, stamp pad, and even hand oil. This is thought to speed up drying and create strong durability against abrasion and abrasion. Therefore, the distribution number of these protrusions is particularly important in balancing the properties, for example
When the number of particles less than 1.5 μm is less than 1,500 pieces/mm ² , the surface becomes rough, and although printing is possible, the sharpness of the image decreases, and in particular, the suitability for thermal transfer printing deteriorates significantly. On the other hand, when the number of particles less than 1.5 μm increases to more than 3000 pieces/mm ² , the surface tends to become smooth, the ink absorption and drying properties decrease, and the printed surface becomes vulnerable to abrasion. This is presumed to be because fine particles less than 1.5 μm absorb ink and cover the surface of the recording sheet, forming an ink surface layer and reducing ink absorption and drying properties. When the number of protrusions of 1.5 to 4.0 μm becomes less than 20,000 pieces/ ^mm2 , the mat-like surface becomes too smooth,
The durability of the print, especially the characteristics against rubbing, deteriorates, and on the other hand, if the number of protrusions exceeds 35,000/mm ² , the surface becomes noticeably rough and the clarity of the print decreases, which is undesirable. Furthermore, if the number of protrusions larger than 4.0 μm is less than 2000 pieces/mm ² , ink absorption and drying properties will deteriorate, causing practical problems ^; If the amount is too large, the surface becomes even rougher, resulting in dance of ballpoint pens and printer pens, skipping, and poor transfer of carbon transfer ink, which is not desirable. The printing layer in the present invention is formed by coating a plastic film with a paint containing a polymer binder, porous fine particles, and, if necessary, a dispersant, dye, antistatic agent, viscosity modifier, etc., and drying the coating. You can. As the polymer binder in the present invention, many known polymer materials can be used as long as they have excellent dispersibility of porous fine particles, excellent bonding properties with plastic films and fine particles, and film-forming properties. can. However, the printing layer of the present invention is exposed to various usage environments, such as being subjected to text corrections and additions with a correction fluid containing an organic solvent, printing with ultraviolet curable ink, being subjected to strong friction, and being exposed to cellophane. Valuable information must not be lost even if adhesive tape such as tape or craft tape is repeatedly attached and detached, so for this purpose, the polymer binder must form a strong coating film through a crosslinking reaction. In particular, from the standpoint of practical production techniques, those that utilize reactions such as isocyanate, melamine, formaldehyde, urea formaldehyde, alkyd condensation reaction, and epoxy reaction are preferred, and isocyanate is more preferred. Examples include those that utilize a urethanization reaction, a melamine formaldehyde reaction, or an epoxy reaction. A print layer that has undergone sufficient crosslinking reaction has high coating hardness, strong durability against scratches, friction, and impact, and will not dissolve, elute, or peel off even when immersed in organic solvents. The result is a coating that does not smudge. Examples of such polymeric binders include phenolic resins, melamine resins, urea resins, benzoguanamine resins, epoxy resins, acrylic resins, acrylic polyol resins, vinyl chloride-vinyl acetate copolymer resins, cellulose resins, polyvinyl alcohol resins, polyester resins, and alkyd resins. Examples include modified resins, polyurethane resins, polyamide resins, and silicone resins. These polymer binders can be used alone or in combination, and furthermore, the polymer binder may include petroleum resins, rosin derivatives, terpene resins, polyolefin resins, etc. to the extent that they improve the coating film formation and physical properties of the coating liquid. Resins such as polystyrene resin, cellulose resin, natural rubber, synthetic rubber, etc. can be added as appropriate. Suitable examples for promoting the crosslinking reaction of these polymeric binders include polyester/isocyanate, polyester/melamine, polyester/urea, and acrylic polyol/
Isocyanate, partially saponified salt/vinyl acetate copolymer/
Isocyanate, partially saponified salt/vinyl acetate copolymer/
Examples include melamine, alkyd/melamine, and the like. The isocyanate used in these is preferably an isocyanate prepolymer from the viewpoint of reaction stability, and includes aliphatic isocyanates such as hexamethylene diisocyanate, aromatic isocyanates such as tolylene diisocyanate, xylene diisocyanate, and the like. Furthermore, as the melamine and urea, partially methylolated melamine, partially methylolated urea, and triazine-containing alkyd resins containing methylol groups can be used. The porous fine particles in the present invention have an average particle size of 5 μm to 20 μm according to the Coulter counter method.
It is preferable that the pore volume is 1.0 to 2.0 ml/g and the internal surface area ratio to the total surface area of the fine particles is 99.5% or more. This average particle size determines the surface shape of the recording sheet, especially the size of irregularities. If the average particle size is smaller than 5 μm, the surface will be too smooth, making writing with a ballpoint pen, pencil, etc. slippery, and making it difficult to write. On the other hand, if the average particle size is extremely large, abnormal protrusions are formed on the surface of the recording sheet.
This is undesirable because it not only tends to cause the recording pen tip to dance or bounce, but also to reduce the amount of ink adhesion and adhesion, and furthermore, the abrasion of the filler particles tends to cause pen clogging. Therefore, the average particle size of the fine particles is preferably from 5 μm to 20 μm, more preferably from 6 to 15 μm. Next, if the pore volume of the particles is smaller than 1.0ml/g, for example, when fingerprints or oil adhere to the surface of the recording sheet, the absorption speed is slow, and if you print on it with a ballpoint pen or dot printer. However, if the pore volume exceeds 2.0ml/g, the pore size becomes too large and the matte coating becomes difficult. When a film is formed, the hardness of the surface decreases and so-called surface protrusions are likely to be scraped, which is not preferable. Furthermore, the ratio of the internal surface area to the total surface area of the fine particles is important for absorbing ink and oil inside the fine particles.In particular, if the internal surface area is small and the external surface area is large, the ink may appear dry after printing. Even if it appears to be stable, the printing may easily disappear or bleed due to rubbing or adhesion of finger oil, resulting in defects. Although the theoretical basis is unknown, it has been empirically shown that the internal surface area ratio to the total surface area of the fine particles is preferably 99.5% or more, as long as no problems occur when actually working as a recording sheet. As long as these requirements are met, fine particles commonly used as matting agents such as silica powder, alumina powder, titanium oxide powder, barium sulfate powder, calcium carbonate powder, antimony oxide powder,
Glass powder, inorganic particles called ceramic powder, organic particles such as polyethylene particles, polypropylene particles, polystyrene particles, benzoguanamine particles, etc. can be used.
More preferably silica fine particles, alumina fine particles,
Examples include glass fine powder and ceramic fine particles.
Furthermore, these may be used alone or in combination of two or more, and fine particles with other characteristics may be added in small amounts within the range without losing the characteristics. Preferred methods for providing such an ink-receiving layer include a coating method, a lamination method, and a melt extrusion method, but among these methods, the method that enables the formation of a more uniform thin film layer, has excellent recording stability, and provides good printing. A coating method is preferable as a method for obtaining this. Examples of coating methods include dip coating, knife coating, roll coating, gravure coating, spray coating, die coating, casting coating,
It can be appropriately selected from spin coating and the like. The thickness of the printing layer is preferably 0.5 to 30 μm, more preferably 2.5 to 10 μm. This layer thickness can be measured with an electronic micrometer. If this thickness is extremely thin, many fine particles will fall off, which is unfavorable in terms of characteristics. Furthermore, if the thickness becomes too thick, no improvement in the properties of the recording sheet will be observed, but rather the printing layer will crack, fall off due to poor adhesion, decrease production speed, and increase costs from an economic standpoint, which is not desirable. . The recording sheet of the present invention can be used, for example, in electronic typewriters, dot printers, thermal transfer printers, etc., and provides clear printing, as well as carbon transfer, non-carbon pressure sensitive transfer, ballpoint pens, magic ink, water-based pens, and ink pads. Copies of etc.
It has excellent printing characteristics, and even if you touch the printing surface with oily fingers or other hands and then print with a ballpoint pen, etc., the printing will not fade or fade, and once printed, it will not rub hard. The print will not disappear even if it is rubbed with an eraser or the like, and stable printing can be maintained for a long time. To explain further, when the recording sheet of the present invention is used as a recording sheet for computer information output devices such as dot printers, electronic printers, and thermal transfer printers, the print is clear, dries quickly, and has excellent print stability. Furthermore, it is suitable for writing with ballpoint pens, pencils, magic ink, water-based pens, etc., as well as carbon transfer ink, non-carbon ink, UV ink, etc., and has excellent ink transferability, clarity, adhesion, and friction durability. It has special properties and can be used for recording sheets for printer hard copies, plotters, facsimiles, etc., and can also be used for frame printing, display printing, carbon transfer coating, non-carbon coating, etc. for delivery, delivery, etc. It is used as a recording sheet for transportation documents, etc., and after being subjected to frame printing, vapor deposition, surface treatment, and back adhesive processing, it is used for nameplates, plates, and labels such as steel labels and equipment labels. In addition, the recording sheet of the present invention can be used to write ID cards, car driver's licenses, etc.
It can be used as a recordable surface, laminated with other sheet materials, or as a molding film for steel plates used in shipbuilding and the steel industry. Of course, the recording sheet of the present invention is not limited to these uses, but the recording sheet of the present invention can be used in a wide range of uses. Examples The present invention will be further explained below with reference to Examples. Note that parts in the examples mean parts by weight. Moreover, each characteristic was determined by the following method. (1) Pore volume Measure using a mercury holosimeter. (2) Internal surface area ratio The internal surface area is defined as the value obtained by subtracting the external surface area when the particle is considered to be a sphere with the average particle diameter from the total surface area of the particle determined by the BET method. The percentage value obtained by dividing by the total surface area is the internal surface area ratio. (3) Adhesion After manually rubbing the sample 10 times and pasting cellophane tape on the surface of the matte layer, it was peeled off and the peeling state of the matte layer was evaluated using a 5-point scale, with 5 being no peeling and 1 being total peeling. (4) Surface hardness Based on JIS S5400 pencil hardness test. (5) Rub Resistance The sample was held between fingernails 10 times and the state of crack peeling on the mat layer surface was visually observed, and evaluated on a 5-point scale with 5 being no peeling and 1 being peeling with a diameter of 3 mm or more. (6) Solvent resistance The number of times the pine surface is rubbed with gauze impregnated with methyl ethyl ketone until the support surface appears. (7) Pencil writing performance Using Mitsubishi Pencil's "Uni", with a load of 500g
Draw a straight line at a speed of 10 cm/sec, magnify the sharpness of the line 25 times with a microscope, 5 means the pencil line is uniform with no change in thickness, and 1 means the pencil line has a markedly darker shade. The line is evaluated on a five-point scale as being broken. (8) Dot printer printing suitability Test printing was performed using an IBM dot printer 5553, and the sharpness of the print pattern was evaluated using the same criteria as pencil writing performance. The dryness of the print is evaluated by rating ○ if there is no problem and × if the print is blurred. (9) Carbon transferability Pitrot carbon paper PCP-100
-B and evaluation samples were stacked alternately on 10 sheets, and IBM
Test printing was performed using printer 5553. The number of sheets that can clearly read the pattern printed by carbon copying is evaluated by the number of sheets stacked from the top, and the higher the number (maximum 10 sheets), the better, and the lower the number, the worse. (10) Ballpoint pen printing suitability When writing the specified print using Zebra Ballpoint Pen N-5000 and rubbing the print with your finger after 30 seconds, the print is marked as ○ if it is not faded, and the mark is marked as × if it is blurred or the base is dirty. evaluate. (11) Fingerprint resistance After pressing your finger strongly against the sample surface, immediately draw 5 straight lines on it with a ballpoint pen (Zebra N-5000). Evaluate something as ×. Example 1 A polymer binder solution containing 15 parts of hexamethylol melamine (NW-30, manufactured by Sanwa Chemical Co., Ltd.) was added to 100 parts of copolymerized polyester resin (Espel 1510, manufactured by Hitachi Koko Kogyo Co., Ltd.), with an average particle size of 12.1 μm (pore size). volume
12 parts and 3 parts of silica (1.2 ml/g, internal surface area ratio 99.6%) and 6.2 μm (pore volume 1.6 ml/g, internal surface area ratio 99.6%), respectively, were mixed at 1.5/min in a 1 gallon sand grinder. A dispersion was prepared at a flow rate of . 15 parts of methyl ethyl ketone and 15 parts of toluene were added to this dispersion to prepare a coating liquid. This coating solution was coated on a biaxially stretched polyethylene terephthalate film using a reverse roll coater to obtain a film thickness of 6.2 μm after drying at 135° C. for 2 minutes to obtain a recording sheet. This sheet exhibits good printing and recording suitability as shown in Table 1 regarding this property.

[Table] Examples 2 to 5 In the same manner as in Example 1, the materials shown in Table 2 were mixed and dispersed in a polymer binder and fine particles, and then coated and dried using a reverse roll coater to obtain the recording sheets shown in Table 2. . These characteristics are shown in Table 3, and all exhibit stable recording suitability. Example 6 The surface of the recording sheet obtained in Example 2 was coated with 400 Å aluminum vapor deposition, a frame was printed on the matte surface, and it was collated with other paper slips to be used as a cover for transportation slips. I created a transportation bill. The address book was printed using carbon transfer printing using a computer dot printer, and the shipping test was repeated, but the printing was clear and maintained a good appearance. Comparative Examples 1 to 4 Recording sheets shown in Table 2 were obtained in the same manner as in Example 1 using the materials shown in Table 2. The properties of these sheets are shown in Table 3, but sheets with sufficient properties could not be obtained due to blurred printing and insufficient transferability.

【table】

[Table] The characteristics of each fine particle in Table 2 are as follows. ●Synthetic silica: Pore volume 1.1-1.6ml/g, internal surface area ratio 99.6% ●Thyroid #162: Pore volume 1.2ml/g, internal surface area ratio 99.6%, average particle size 8.5μm ●Thyroid #308: Pore Volume 1.25ml/g, internal surface area ratio 99.5%, average particle size 7.0μm ●Thyroid #244: Pore volume 1.6ml/g, internal surface area ratio 98.7%, average particle size 3.5μm ●Thyroid #150: Pore volume 1.6 ml/g, internal surface area ratio 98.5%, average particle size 2.5μm ●Nipsheet LP: Pore volume 1.25ml/g, internal surface area ratio 99.6%, average particle size 8.9μm ●Nipsheet E150K: Pore volume 1.59ml/g, Internal surface area ratio 98.7%, average particle size 4.5μm ●ATTA CLAY X250: Average particle size 1.5μm, internal surface area ratio 55.0%

【table】

Claims (1)

[Claims] 1. A recording sheet having a printing layer provided on a plastic film, wherein the surface of the printing layer is roughened with a large number of protrusions, and the relationship between the height of the protrusions and the number thereof is as shown below. Height (h) of protrusions and their number h < 1.5 μm: 1500 to 3000 (pieces/mm ² ) h = 1.5 to 4.0 μm: 20000 to 35000 (pieces/mm ² ) h > 4.0 μm: 2000 to 4000 (pieces/mm 2 ) /mm ² ). 2. The record according to claim 1, wherein the printing layer comprises a polymer binder and porous fine particles, and the fine particles have an average particle size of 5 to 20 μm, a pore volume of 1.0 to 2.0 ml/g, and an internal surface area ratio of 99.5% or more. sheet. 3 The amount of porous fine particles is 100% of the polymer binder.
Claim 2: 10 to 100 parts by weight
Record sheet listed.