JPH09290577A - Printing sheet and printed sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the favorable formation of a highly gradated pattern with a hot melt type printer and obtained the excellent fixing properties and chemical resistance of ink by a structure wherein this sheet is made of a porous layer, which is formed by three-dimensionally expanding a large number of fine fivers under the state being formed into a large number of minute knotted parts, and when necessary, a reinforcing base material is provided. SOLUTION: This sheet is made of a porous layer 1, which is produced by three- dimensionally forming a large number of fne fibers under the state being formed into a large number of minute knotted parts. In addition, when necessary, a reinforcing base material 2 is provided through an adhesive layer 21. Fo example, a printed sheet, which is prepared by giving an ink pattern 4 to the porous layer, is bonded through a self-adhesive layer 3 to an adheren 5. As the porous layer, any properly-shaped matter having an ink accepting layer will do or a composite body of the porous layer 1 as the ink accepting layer and the reinforcing base material 2 also will do. By means of the porous layer, a printed sheet, which is excellent in internal permeability and high speed permeability due to cappilarity and to which an information having high recording density is given with a hot melt type printer or the like according to circumstances, can be issued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing sheet which can print fine ink information with high accuracy and high fixability by various printing methods such as a printer, and a printing sheet including its label.

[0002]

Background of the Invention As the production system shifts to high-mix low-volume production, it is difficult to use high-mix low-volume production system because it is difficult to issue a metal stamp with a pattern engraving, a heat-resistant sheet with a hardened ink pattern or a metal plate. For this reason, various printing sheets have been proposed that allow an ink sheet to be issued on a supporting base material, which allows the printing sheets to be printed flexibly, such as higher gradation of ink information, higher definition, and higher recording density. Various types of ink-receiving layers formed of a porous layer have been proposed for the purpose of achieving high image quality (Japanese Patent Application Laid-Open No. 62-79237, Japanese Patent Application Laid-Open No. 62-197183, and Japanese Patent Application Laid-Open No. 1-295890). JP-A-2-41287 and JP-A-2-147.
232, JP-A-6-171250, JP-A-7-1846, JP-A-7-100981,
JP-A-7-125468).

However, even if the ink-receiving layer is a porous layer, the recording density is poor, and when the heat-melting printer is used, it is 50% less than when the heat-sublimation printer is used.
Poor reproducibility of small dots of μm or less, poor formability of high-gradation patterns, poor penetration speed of color ink, and second, third, fourth, etc. dots reproduction with the progress of multicolor There was a problem that it deteriorated. By the way, in a thermal fusion printer using a variable dot size thermal head, the higher the reproducibility of small dots, the higher the gradation,
High-definition, full-color printing is achieved.

Further, even in a printing sheet having an ink receiving layer composed of a polymer layer containing an inorganic powder on a polyimide film or the like (JP-A-3-175023), when a thermal transfer pattern of a resin-based ink is applied. Thermal transfer errors such as ink bleeding frequently occur, making it difficult to print at high density. High-density printing is becoming an indispensable condition because of miniaturization of label size accompanying downsizing of printed circuit boards and electronic parts, for example.

Further, in the above case, when the obtained printed sheet is subjected to, for example, a mounting process of a printed circuit board, a solder bath of a web solder method or a reflow method after applying flux is applied at about 300 ° C. for 1 minute. There is also a problem that the ink pattern elutes and decomposes by heating within the following range, and the ink pattern disappears afterwards by treatment with pure solvent such as trichloroethane, freon-based or alternative freon-based solvent, pure water, etc. It was

[0006]

DISCLOSURE OF THE INVENTION The present invention is excellent in reproducibility of recording density and large and small dots, and can form a high gradation and high definition pattern well even when using a heat-melting type printer. It is also excellent in clear formation of multi-colored patterns, and it is also possible to issue high-density information through various printers when printing sheets are issued. In the case of thermal transfer patterns using resin-based ink, ink fixing is also possible. A printing sheet that is excellent in heat resistance, scratch resistance, solvent resistance, and other chemical resistance and that can provide clear, high-density ink information with high image quality and can adhere to a reinforcing base material if necessary. Development is an issue.

[0007]

Means for Solving the Problems The present invention relates to a porous layer in which a large number of fine fibers are three-dimensionally developed with a large number of minute knots, such as a three-dimensional skeleton-like porous structure layer made of fine fibers. The present invention provides a printing sheet characterized by comprising a reinforcing base material as necessary, and a printing sheet characterized by having an ink pattern applied to the porous layer thereof.

【The invention's effect】

Due to the porous layer having the above-mentioned structure, it is possible to obtain high recording density information through various printers such as a heat-melting type, a heat sublimation type, a heat transfer type and an ink jet type, which has excellent internal permeability and high-speed permeability of ink due to a capillary phenomenon. It is possible to issue a print sheet with the opportunity to add. In addition, it is possible to form a high-definition dot pattern with excellent reproducibility of large and small dots, especially small dots, and further, it is possible to form a high-concentration pattern with high sensitivity, probably due to the heat storage effect of the thermal head by the porous layer. In addition, if necessary, a reinforcing base material can be closely adhered to the porous layer to provide the required sheet strength.

Therefore, a pattern of high recording density can be formed by using various printers, and when using a heat-melting printer, excellent reproduction of small dots and high-speed penetration of ink can form a clear pattern with high gradation of multicolor. When using a thermal sublimation type printer, a pattern with high recording density due to good dyeing properties can be obtained.When using a thermal transfer type or ink jet type printer, good internal penetration and absorption of ink, and quick drying can be used to fix, heat resistance, and scratch resistance. It has excellent chemical resistance such as solvent resistance and can form high-quality patterns and highly durable printed images.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The printing sheet of the present invention comprises a porous layer in which a large number of fine fibers are three-dimensionally developed in the state of forming a large number of fine knots. Examples thereof are shown in FIGS. 1 and 2. Reference numeral 1 is a porous layer, 2 is a reinforcing base material provided as required, and 21 is an adhesive layer thereof. In the illustrated example, a print sheet having the ink pattern 4 applied to the porous layer is adhered to the adherend 5 via the adhesive layer 3.

The printing sheet may be in any suitable form having the porous layer as an ink receiving layer. Incidentally, examples thereof include a single-layer sheet form composed of the porous layer itself, a superposed form of the porous layer 1 and the reinforcing base material 2 as illustrated in FIG. 1, and a porous layer 1 and the reinforcing base material 2 as illustrated in FIG. Adhesive layer 2
1 and the adhesive layer 3 may be attached to the back surface of the non-printing side.

The porous layer according to the present invention can be formed by, for example, a method of spraying a solvent for coagulating the polymer onto an undried developing layer made of a polymer solution to solidify the developing layer. That is, a suitable polymer is dissolved in a solvent to form a solution, which is then spread to form a spreading layer, and the spreading layer contains a solvent and is in an undried state, and the solvent in the spreading layer is The porous layer according to the present invention can be formed by, for example, a method of spraying a coagulation solvent that is compatible and does not dissolve the polymer to solidify the spreading layer. In this case, an additive such as a solid plasticizer that is soluble in both the solvent for the polymer and the solvent for coagulation may be blended.

In the above description, the thickness of the spreading layer of the polymer solution can be appropriately determined, but it is generally 1 mm or less, preferably 10 to 500 μm, especially 20 from the viewpoint of the structure controllability of the porous layer.
~ 200 μm. The step of spraying the coagulation solvent is preferably such that the solvent remains sufficiently in the spreading layer from the viewpoint of the structure controllability of the porous layer. If the amount of solvent in the spreading layer is small, a porous layer formed by three-dimensionally spreading a large number of fine fibers with a large number of minute knots is not formed.

The amount of the solvent present in the spreading layer that is preferable for forming the porous layer is based on the state in which undissolved components such as the filler are removed, for example, 80% by weight or more for cellulose acetate,
It is 85% by weight or more for polymetaphenylene isophthalamide, and 92% by weight or more for polyvinyl butyral or polyvinyl acetal. It depends on the type and composition of the polymer, the structure, the molecular weight, etc. Based on the state excluding undissolved components,
It is preferable to spray the coagulating solvent at a stage where 50% by weight or more, especially 70 to 99% by weight, and particularly 80 to 97% by weight of the solvent is present in the spreading layer.

The processing temperature for developing the polymer solution and spraying the coagulating solvent can be appropriately determined, and is generally 0 to 80 ° C, preferably 0 to 40 ° C. When the viscosity of the polymer solution is low, it is preferable to lower the temperature, especially to 0 to 10 ° C. to increase the amount of the solution clay and use it for forming the spreading layer. In that case, the developing atmosphere and the spraying temperature of the solidifying solvent are also 0 to 1.
It is preferable to lower the temperature to 0 ° C or the like.

The spraying of the coagulation solvent to the spreading layer is carried out by an appropriate contact method such as a method of introducing the spreading layer into the vapor bath of the coagulating solvent or a method of spraying the coagulating solvent on the spreading layer. You can The coagulation solvent can be sprayed from one side or both sides of the spreading layer. The particle size of the spray particles is
500 μm or less due to the miniaturization of the porous structure, especially 1
It is preferably 00 μm or less, and particularly preferably 10 μm or less.

The coagulating solvent sprayed on the spreading layer is absorbed by coming into contact with the spreading layer, diffusively mixed in the solvent in the spreading layer, and the polymer dissolving power of the solvent is lost to solidify the polymer.
Such coagulation phenomenon proceeds from the surface of the development layer to the inside as the coagulation solvent diffuses and permeates into the development layer. On the other hand, the solvent mixed with the coagulation solvent whose permeation is blocked by the coagulation of the polymer accumulates in the gaps of the coagulated polymer and is spheroidized by the action of the intermolecular cohesive force, and this spheroidization also progresses from the surface of the spreading layer to the inside.

The above-mentioned spheroidized solvent mixed with the coagulating solvent, when the size thereof reaches a certain level, causes the expansion pressure to exceed the surface tension and is connected to adjacent spheres inside the spreading layer, and this connection phenomenon develops. Proceeds into the layer. As a result, as shown in FIG. 3, a porous layer in which a large number of fine fibers are three-dimensionally developed while forming a large number of fine knots, that is, a large number of fine fibers are derived in various directions. The (fine knots) are grouped in a three-dimensional space with a minute distance, and the porous layer having a communication structure in which a large number of the derived fine fibers are connected between the points is formed.

Since the solidification of the polymer proceeds from the surface of the spreading layer to the inside as described above, the formation thickness (depth) of the porous layer can be controlled through the contact time with the sprayed solvent for solidification. The whole or part of the thickness of the spreading layer can be made into a porous layer. Therefore, the spraying time of the coagulation solvent can be appropriately determined according to the thickness of the spreading layer, the target formation thickness of the porous layer, etc., but is generally about 5 seconds to 20 minutes.

The polymer used for forming the porous layer is not particularly limited, and an appropriate polymer may be used depending on the physical properties of the printing sheet depending on the purpose of use. Generally, for example, urethane type polymers, polystyrene or polyvinyl chloride, vinyl chloride / vinyl acetate copolymers or polyvinyl acetate, polyvinyl butyral or polyvinyl formal, vinyl type polymers such as polyvinyl acetal or polyvinyl hydroxide, polyethylene terephthalate or Ester-based polymers such as polyethylene naphthalate, acrylic-based polymers such as polymethylmethacrylate and polyacrylate are used.

Further, cellulose-based polymers such as ethyl cellulose and cellulose acetate, olefin-based polymers such as polyethylene and polypropylene, ethylene-vinyl acetate copolymers, styrene-isoprene copolymers, styrene-butadiene rubbers, nitrile rubbers and polybutadienes. Rubber polymers, polyacetals, various amide polymers such as aliphatic and aromatic polymers, polysulfones and polyimides, epoxy resins and polyetheretherketones, polyethersulfones and polyetherimides can also be used for forming the porous layer. .

Further, polyphenylene sulfide, polyamide imide, polyester imide, polyparabanic acid, silicone type polymer, fluorine type polymer, xylene type polymer, polyvinylidene chloride, polycarbonate and polyarylate can be used for forming the porous layer. From the viewpoint of versatility as a printing sheet, urethane polymers, polyvinyl butyral, polyvinyl acetal, cellulose acetate, aromatic polyamides, epoxy resins, polyimides and the like can be preferably used. The polymers for forming the porous layer may be used as a blend of two or more kinds.

As the solvent for the polymer, any suitable solvent which is compatible with the coagulating solvent and insolubilizes the polymer by mixing with the coagulating solvent may be used. Generally, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide,
Amide solvents such as N, N-dimethylformamide, hexane and heptane, cyclohexane and cycloheptane,
Hydrocarbon solvents such as benzene, toluene, xylene and acetone are used. Among them, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, acetone and the like can be preferably used from the viewpoint of controllability of the porous structure.

One or more solvents for the polymer can be used. The concentration of the polymer solution can be appropriately determined depending on the coatability and the desired porous structure, and is generally 1 to 50% by weight, and particularly 3 to 30% by weight. In the polymer solution, a thickener for the purpose of improving coatability, a hydrophilicity-imparting agent for the purpose of imparting hydrophilicity, strength and concealment of the porous layer to be formed, and adjustment of the porous structure. Alternatively, for the purpose of improving contrast with applied ink information by coloring, improving heat resistance, and the like, appropriate additives and agents such as coloring agents such as fillers and white pigments, antioxidants, and the like are added as necessary. It can be blended.

On the other hand, as the coagulating solvent, a solvent which is compatible with the polymer solvent and does not dissolve the polymer is used. There is no particular limitation on the type. Generally, one or more polar solvents are used according to the type of the polymer solvent. Examples thereof include water, alcohols such as methanol, ethanol and propanol, and glycols such as ethylene glycol and propylene glycol.

In the present invention, a polymer made of polyvinyl butyral, polyvinyl acetal, cellulose acetate, aromatic polyamide, epoxy resin or polyimide is added to N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N- A porous layer formed by spraying water on a developing layer of a solution dissolved in a solvent composed of dimethylformamide is particularly preferable from the viewpoint of properties as a printing sheet.

The coagulated layer of the polymer formed by spraying the coagulating solvent is washed with water or the like, if necessary, and dried by an appropriate method such as a heating method or a vacuum method to obtain a target porous layer. . The porous layer can also be formed as a superposed layer by repeating the above-described porous layer forming operation. Further, the obtained porous layer,
It can also be stretched to control its porous structure.

From the viewpoint of ink permeability and layer strength, the preferred porous layer has a porosity, that is, a volume ratio of pores in the porous layer is 40 to 95%, and more preferably 45 to 90%. In particular, those having a three-dimensional skeleton-like porous structure due to their porosity are preferable, and in that case, those having all pores in a communicating structure are more preferable.

The pore size on the surface of the porous layer is preferably 1 to 10 μm based on the circle, from the viewpoints of internal permeability of ink due to capillary action, high-speed permeability, reproducibility of small dots, etc. From the viewpoint of printing characteristics and strength, 25 to 95% of the pores having such a diameter are formed on the surface of the porous layer, especially 3
Those having an area ratio (opening ratio) of 0 to 90%, particularly 35 to 80% are preferable.

The thickness of the porous layer can be appropriately determined according to the purpose of use of the printing sheet, etc., and is generally 0.5 to 500 μm, preferably 1 to 300 μm in view of strength and ink fixability.
μm, particularly 2 to 20 μm. The porous layer may be subjected to an appropriate surface treatment such as corona treatment, plasma treatment or chemical etching treatment for the purpose of improving ink permeability.

As shown in FIGS. 1 and 2, the printing sheet of the present invention uses the porous substrate 1 as the ink receiving layer and the reinforcing substrate 2 as the ink receiving layer.
Can be a complex with. In that case, for example, a double-sided printing type sheet can be formed by a method in which the porous layer is provided on both sides of the reinforcing base material, as in the case where the porous layer is a single layer sheet.

The attachment of the porous layer to the reinforcing base material may be carried out by a method of adhering the porous layer to the reinforcing base material via an adhesive layer or the like,
It can be carried out by an appropriate method such as a method of applying or dipping the above-mentioned spreading layer to the reinforcing base material to form a porous layer. The latter method has an advantage that a sheet having a reinforcing base material can be efficiently manufactured with easy handling.

As the reinforcing base material, for example, paper, non-woven fabric, cloth, metal foil, net, resin film, or other suitable material or form may be used depending on the intended use of the printing sheet. By selecting the reinforcing base material, it is possible to appropriately adjust physical properties such as flexibility such as curved surface adhesion and heat resistance, and it is also possible to improve contrast with ink information to be imparted through the reinforcing base material.

Incidentally, examples of the above-mentioned paper include high-quality paper, art paper, natural paper such as coated paper and glassine paper, and polypropylene synthetic paper. As the resin film, in addition to the polymer exemplified as the material for forming the porous layer, epoxy acrylic resin, urethane acrylic resin, polyester acrylic resin or acrylic ester resin, alkyd acrylic resin or silicone acrylic resin is used. Resins, and polyene / polythiol-type spirane-based resins and UV-curable resins such as aminoalkyd-based resins are also included.

The reinforcing base material may be treated with an anchor coating agent, if necessary, for the purpose of improving the adhesion of the porous layer. From the viewpoint of the adhesion between the reinforcing base material and the porous layer, etc., a preferable method is a method of performing an adhesion treatment via the adhesive layer 21 as illustrated in FIG. An appropriate adhesive substance can be used to form the adhesive layer, but it is preferable to use resins of the same quality as the porous layer from the viewpoint of improving the adhesion force by forming a large adhesive area with the porous layer. . Therefore, examples of the adhesive substance include the polymers exemplified in the above porous layer.

In the above, in the case of forming a printing sheet by providing a spreading layer on a stretchable reinforcing base material such as paper and making it into a porous layer, while applying tension to the reinforcing base material, Alternatively, it is preferable to prevent wrinkles from occurring by an appropriate method such as a method of drying the reinforcing base material along the drum.

The printing sheet of the present invention may be provided with an adhesive layer on the back side of the non-printing side, if necessary. For forming the adhesive layer, for example, an appropriate adhesive such as rubber, acrylic, silicone, vinylalkyl ether, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, or cellulose can be used. The adhesive layer is intended to be attached to the adherend, and can be provided at an appropriate stage until it is attached to the adherend, or can be provided in advance on the printing sheet before ink information is provided. However, it can also be provided after forming a printed sheet.

The adhesive layer may be attached by a coating method such as a doctor blade method or a method of directly attaching it to a printing sheet, or by forming an adhesive layer on a separator and applying the adhesive layer to the printing sheet or printing sheet. It can be performed by an appropriate method such as a method of transferring to. The thickness of the attached adhesive layer can be determined according to the purpose of use and is generally 1 to 500 μm.
m. The adhesive layer provided is preferably covered with a separator or the like to prevent contamination or the like until it is adhered to an adherend.

The printing sheet of the present invention, as described above,
Various types of printer paper, label paper, etc., due to their excellent internal penetration (absorption) of ink, penetration speed and dryness, reproducibility of small dots, recording density, recording density due to high sensitivity, and ink fixability. It can be used as a paper by various printing methods such as the above printing paper or a plastic raw material for printing.

The printing sheet can be formed by applying ink information or a pattern to the porous layer of the printing sheet. The applying method is arbitrary, and an appropriate method such as a handwriting method, a printing method, or an ink applying method through a mask can be adopted. In addition to the screen printing method and the gravure printing method, there are various printing methods such as heat melting type, heat sublimation type, thermal transfer type, ink jet type, XY plotter type, wire dot type and impact type printing methods. There is no particular limitation on the printing apparatus, and an appropriate printing apparatus can be used.

According to the printing sheet of the present invention, even in a thermal fusion printer using a thermal head having a variable dot size, dot reproducibility in a low gradation portion is excellent and a high gradation high quality pattern is formed. Even if it is a thermal sublimation printer, it is possible to form a pattern of high recording density with excellent dyeability, and it is possible to form a clear multicolor color pattern or a durable print image. Further, an ink jet type printer is excellent in ink absorption and quick drying property, and a thermal transfer type printer is excellent in ink fixing property, and a fine pattern having a high recording density can be formed.

Further, as the ink, the ink sheet and the like, appropriate ones can be used. The ink information to be given is arbitrary,
Arbitrary information composed of characters, figures, symbols, etc., such as a print pattern, a picture pattern, and a bar code pattern may be added. When an identification label or the like is formed, it is preferable that a good contrast or a difference in color tone be formed between the printing sheet and the ink information.

The printing sheet can be used for printing in an appropriate form such as a long sheet, a single sheet, or a punched sheet, and the necessary ink information can be added at the site to issue the printing sheet on demand. It is also possible to obtain a printing sheet having excellent scratch resistance and heat resistance that endure cleaning and wiping with a solvent.

[0044]

【Example】

Example 1 Polyvinyl acetal (manufactured by Sekisui Chemical Co., Ltd., S-REC KS-5) (100 parts by weight, hereinafter the same) was dissolved at 80 ° C. with 1330 parts of N, N-dimethylformamide and 230 parts of glycerin, and the polymer thereof was dissolved. After leaving the solution in a closed atmosphere at 5 ° C for 2 hours, the thickness of the solution should be 100 ° C in the atmosphere at 5 ° C.
After applying a thickness of about 100 μm on a white polyethylene terephthalate film of μm through an applicator and holding it vertically at 5 ° C. for 15 minutes, supplying spray water through a commercial humidifier, After washing with water for about 10 minutes at room temperature and drying, many fine fibers spread out in three dimensions while forming many minute nodules, and the porosity is 80%, and the pore diameter in terms of circle is 1 to 10 μm. It has a solid skeleton-like communication structure with an area ratio of about 40% on the surface and a thickness of 25.
A printing sheet having a μm porous layer (ink receiving layer) was obtained. It is to be noted that FIG. 3 shows a magnified plan view of the printing sheet (2
000 times).

Example 2 Polyvinyl butyral (Sekisui Chemical Co., Ltd., S-REC BX-5) 100 parts was added to N-methyl-2-pyrrolidone 19
According to Example 1, using a polymer solution dissolved at 00 parts at 80 ° C., a large number of fine fibers are three-dimensionally developed while forming a large number of fine knots, and the porosity is 85%. Approximately 50% of holes with a circle equivalent hole diameter of 1-10 μm on the surface
A sheet for printing having a porous layer having a three-dimensional skeleton-like communication structure having an area ratio of 25 μm and a thickness of 25 μm was obtained.

Example 3 Cellulose acetate resin (manufactured by Daicel, cotton acetate L-40)
8 parts of 100 parts with 900 parts of N, N-dimethylacetamide
According to Example 1, using a polymer solution dissolved at 0 ° C., a large number of fine fibers were three-dimensionally developed while forming a large number of minute knots, and the porosity was 75%, which was converted into a circle. A solid skeleton-like communication structure having pores with a diameter of 1 to 10 μm at an area ratio of about 45% on the surface and a thickness of 25 μm
A printing sheet having a porous layer of was obtained.

Example 4 Polymetaphenylene isophthalamide (30 parts), titania (50 parts), calcium carbonate (30 parts), talc (20 parts) and N, N-dimethylacetamide (185 parts) were uniformly kneaded in a roll mill to form a paste. It was cast on a polyimide film with a thickness of 50 μm by the doctor blade method at room temperature, sprayed with water for 5 minutes through a commercially available humidifier, washed with water for about 5 minutes and dried, and a large number of fine fibers It develops three-dimensionally while forming various nodules, and has a porosity of 70% and a circle-equivalent hole diameter of 1 to 10 μm.
A printing sheet having a porous layer with a thickness of 25 μm, which has a three-dimensional skeleton-like communication structure having m holes at an area ratio of about 35% on the surface and has a filler such as titania dispersed therein, and acrylic acid on the back surface is obtained. A 30 μm-thick acrylic adhesive layer containing a 2-ethylhexyl copolymer as a main component was provided to cover and protect with a separator.

Example 5 15 parts of polymetaphenylene isophthalamide was mixed with 85 parts of N, N-dimethylacetamide on a polyimide film.
Example 4 except that the dissolved solution was cast into a part to form a 3 μm thick adhesive layer, and a 10 μm thick porous layer (surface roughness Ra: 0.05 μm) was formed on the adhesive layer. A printing sheet was obtained according to.

Example 6 On one side of a 50 μm thick polyetherimide film,
20 parts of a thermoplastic polyimide having a softening point of 250 ° C. is N, N-
A solution prepared by dissolving 85 parts of dimethylacetamide was cast to form an adhesive layer having a thickness of 5 μm, and 100 parts of titania and the thermoplastic polyimide 4 were formed on the adhesive layer.
A paste obtained by uniformly kneading 0 parts and 185 parts of N, N-dimethylacetamide with a roll mill was cast by a doctor blade method at room temperature to have a thickness of 25 μm.
A printing sheet was obtained in the same manner as in Example 4 except that the porous layer (surface roughness Ra: 0.05 μm) was formed. On the back side, a butyl acrylate copolymer is the main component and the thickness is 20μ.
An acrylic adhesive layer of m was provided.

Comparative Example 1 A printing sheet having a porous layer with a thickness of 25 μm was prepared according to Example 1 using a polymer solution prepared by dissolving 100 parts of polyvinyl acetal in 900 parts of N, N-dimethylformamide at 80 ° C. Obtained. However, the porous layer has a continuous three-dimensional skeleton structure in which holes are drilled in each of the vertical axis, the horizontal axis, and the front-back axis of Cartesian coordinates, and a large number of substantially circular holes with a uniform diameter are formed on a smooth surface. In the opened state, the pores had a porosity of 75% and a circle-converted pore diameter of 1 to 10 μm at an area ratio of about 10% on the surface. In Fig. 4, a magnified plan view of the printing sheet (2000x)
showed that.

Comparative Example 2 25% by weight of vinyl chloride / vinyl acetate copolymer N, N-
A polymer solution comprising a mixture of 100 parts of a dimethylformamide solution and 40 parts of a 25% by weight N, N-dimethylformamide solution of an acrylonitrile / methyl acrylate copolymer was provided on a white polyethylene terephthalate film having a thickness of 100 μm. Approximately 100μ thick on the coated surface of saturated polyester resin through an applicator at room temperature
Apply to m and soak it in a water bath at 20 ℃ for 1 minute.
It has a finger-shaped structure in which it is dipped in a hot water bath at 0 ° C for 5 seconds to be dried, and is perforated in the vertical axis direction of the Cartesian coordinates. A smooth surface has a large number of substantially circular holes of non-uniform diameter. A printing sheet having a 25 μm-thick porous layer having a porosity of 70% and a circle-converted hole diameter of 1 to 10 μm in an area ratio of about 25% on the surface was obtained.

Comparative Example 3 Polyester resin (manufactured by Toyobo Co., Ltd., Byron 200) 1
9 parts, 14 parts of silica powder having an average particle size of 2.3 μm, 40 parts of toluene, and 40 parts of methyl ethyl ketone are dispersed by a ball mill, and then isocyanate (made by Morohoshi Ink Co.,
XEL-D) 9 parts of a polymer solution is applied onto a white polyethylene terephthalate film having a thickness of 100 μm at room temperature with an applicator, and dried to have an ink receiving layer having a thickness of about 20 μm for printing. Got the sheet. This ink receiving layer is a porous layer having pores having a void between silica powders of 30% or less, a porosity of 30% or less, and a circle-converted pore diameter of 1 to 10 μm in an area ratio of 30% or less on the surface. Met.

Comparative Example 4 A printing sheet having an ink receiving layer having a thickness of 1 μm was obtained in the same manner as in Example 4 except that the water spraying step and the water dipping step were omitted. No holes were observed on the surface of the ink receiving layer.

Comparative Example 5 A printing sheet was obtained in the same manner as in Example 5, except that no adhesive layer was provided between the polyimide film and the porous layer.

Comparative Example 6 A printing sheet was obtained in the same manner as in Example 6 except that no adhesive layer was provided between the polyimide film and the porous layer.

Evaluation Test A print sheet was obtained by applying a predetermined pattern to the ink receiving layers of the printing sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 3 with a commercially available heat-melting color printer to obtain gradation. The property, sensitivity, color density, small dot reproducibility, third color reproducibility, and pattern fixability were examined by lightly scratching the pattern with a nail. The results are shown in Table 1.

[Table 1]

Line Width Printability A predetermined pattern was applied to the ink receiving layers of the printing sheets obtained in Examples 4 to 6 and Comparative Examples 4 to 6 with a thermal transfer printer (Duraprinter SR, manufactured by Nitto Denko Corporation). A print sheet was obtained and the line width printability was examined.

Fixability Regarding the printing sheet for line width printing of 250 μm obtained above, the separator on the back side was peeled off and adhered to a glass / epoxy substrate, and the non-woven fabric impregnated with a solvent was wiped off the patterning surface to form a pattern. The remaining state of was investigated. Also 26
A solder flow (web soder) test was performed at 0 ° C. for 5 seconds to examine the residual state of the pattern.

The above results are shown in Tables 2 and 3. In addition, TCE in the table means trichloroethane, and cleansing 750H manufactured by Kao Corporation was used as a detergent.

[Table 2]

[0060]

[Table 3]

Adhesion of Porous Layer A pattern having a line width of 250 μm was applied to the printing sheets obtained in Examples 5 and 6 and Comparative Examples 5 and 6 in the same manner as described above to obtain a printing sheet, and the porous layer (ink The surface of the receiving layer) was scratched with a nail slightly stronger than the pattern fixing property test described above, and the remaining state was examined. The results are shown in Table 4. In addition, excellent in the example means that the porous layer was not peeled off including the applied pattern, and the defect in the comparative example was
This means that the porous layer was peeled off from the reinforcing film.

[0062]

[Table 4]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a printed sheet.

FIG. 2 is a cross-sectional view of another printed sheet example.

FIG. 3 is a photograph (planar view) of a porous layer composed of a thin film in the printing sheet obtained in Example 1.

FIG. 4 is a photograph (planar view) of a porous layer formed of a thin film in the printing sheet obtained in Comparative Example 1.

[Explanation of symbols]

 1: Porous layer (ink receiving layer) 2: Reinforcing base material 21: Adhesive layer 3: Adhesive layer 4: Ink pattern 5: Adherend

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Naofumi Mihara 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (8)

[Claims] 1. A printing sheet comprising a porous layer in which a large number of fine fibers are three-dimensionally developed with a large number of fine knots formed. 2. The porous layer according to claim 1, wherein the porous layer has a three-dimensional skeleton-like communication structure, and the porosity is 40 to 95%.
Is a printing sheet. 3. The porous layer according to claim 1 or 2, wherein the surface of the porous layer has pores having a diameter of 1 to 10 μm in terms of circle.
A printing sheet having an area ratio of 5%. 4. The printing sheet according to claim 1, wherein the porous layer has a reinforcing base material. 5. The printing sheet according to claim 4, which has an adhesive layer between the porous layer and the reinforcing substrate. 6. The printing sheet according to claim 5, wherein the adhesive layer is made of the same resin as the porous layer. 7. The printing sheet according to claim 1, which has an adhesive layer on the back side of the non-printing side of the sheet. 8. A printing sheet obtained by applying an ink pattern to the porous layer of the printing sheet according to claim 1.