JPH08324096A - Ink jet recording film - Google Patents

Abstract

PURPOSE: To provide an ink jet recording film enhanced in drawing properties, less apt to generate wrinkles and a curl and containing a large number of fine voids in an ink jet printer. CONSTITUTION: In an ink jet recording film wherein an ink receiving layer is provided on at least the single surface of a base material film, the base material film has voids therein and a ratio L/T of the average length L and average thickness T of voids present in the cut surface formed by cutting the base material film in one arbitrary direction vertical to the surface of the film is 7.0 or more and the number (n) of the voids contained in the base material film is 30/2500μm<2> or more and the apparent specific gravity of the whole is 0.6-1.3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording film which does not easily curl or wrinkle in a printer, and more specifically, an ink jet recording film containing a large amount of fine voids inside the film and having an improved drawing property. Film.

[0002]

2. Description of the Related Art Synthetic paper, which is a paper substitute mainly made of synthetic resin, has a higher water resistance, a higher dimensional stability in moisture absorption, and a higher dimensional stability than natural paper.
It has excellent surface stability, gloss and clarity of printing, and mechanical strength. In recent years, application development has been promoted by making use of these advantages.

In recent years, with the spread of electronic still cameras or computers, hard copy technology for recording those images on a paper surface has rapidly developed. The ultimate goal of these hard copy technologies is silver halide photography, and in particular, how to bring color reproducibility, image density, gloss, weather resistance, etc. closer to those of silver halide photography is an issue for development. As a hard copy recording method, in addition to a method of directly photographing a display on which an image is displayed by a silver salt photograph, many methods such as a sublimation type thermal transfer method, an ink jet method, an electrostatic transfer type method are known.

An ink jet printer is
Due to easy full-colorization and low printing noise, it has become rapidly popular in recent years. Inkjet printers eject ink droplets at high speed from a nozzle toward a recording sheet, which is a recording material, and the ink contains a large amount of solvent. Therefore, the recording sheet for the inkjet printer quickly absorbs the ink,
Moreover, it is required to have excellent color development.

For this recording sheet, a base material of natural paper is most popular. However, there is a problem in that when the ink is absorbed by the recording sheet, the paper as the base material is wrinkled, and the appearance of the image is impaired.

In order to solve such problems, many synthetic papers based on polyolefin films and polymer films have been proposed. However, there is a problem that these films or synthetic papers become thick in order to have sufficient rigidity.

Further, in order to solve such a problem and enable folding like natural paper, a polyester film having many cavities inside is used as a base material of a recording sheet. Such a base sheet is obtained, for example, by stretching an unstretched film produced by adding inorganic particles or a resin incompatible with the base resin. However, the polyester film has uneven orientation in the longitudinal direction and the transverse direction due to stretching, and when the voids present inside are too large, wrinkles or curls are newly generated especially when used in a large-sized inkjet printer. There is a problem that occurs. JP-A-63-168441
The publication limits the size of the cavities in such polyester films, which are still too large to be sufficient to solve the above problems. JP-A-63-19393
No. 8 and Japanese Patent Laid-Open No. 3-76727 disclose that a surfactant or a polyalkylene glycol such as polyethylene glycol is added to a base film to reduce voids. However, since the base film containing a surfactant has a low molecular weight surfactant on the surface of the base film, when an ink receiving layer is provided on the base film, repelling or uneven coating occurs. . Furthermore, the base film containing polyethylene glycol lowers the apparent specific gravity of the entire recording film, but it is difficult to form many fine voids in the base film. As a result, the recording film having such a base film cannot prevent the occurrence of wrinkles or curls at the time of printing, especially for a large-sized inkjet printer.

[0008]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems. By optimizing the size of the cavity in the substrate film, the ink can be absorbed quickly and the film surface can be improved. It is an object of the present invention to provide an ink jet recording film which improves the image drawing property and prevents wrinkles and curls from being generated at the time of printing for an ink jet type printer, particularly a large size printer.

[0009]

The ink jet recording film of the present invention comprises:
An inkjet recording film having an ink receiving layer, wherein the base film has cavities inside, and cavities present on a cut surface when cut in any one direction perpendicular to the base film surface. Ratio L / T of the average L of the lengths to the average T of the thicknesses of the cavities is 7.0 or more, and the number n of the cavities contained in the base film is 30 / 2,500 μm ^2.
And the overall apparent specific gravity is 0.6 or more.
3 or less. Thereby, the above object is achieved.

In a preferred embodiment of the present invention, the base film is obtained by orienting at least uniaxially a polymer mixture containing a polyester and a thermoplastic resin incompatible with the polyester. It is a film having various cavities. In a preferred embodiment of the present invention, an easy-adhesion layer and an ink receiving layer are sequentially provided on at least one surface of the base film, and the easy-adhesion layer is selected from polyester resin, polyacrylic resin, and polyurethane resin. It contains at least one kind.

In a preferred embodiment of the present invention, the easily adhesive layer and / or the ink receiving layer contains particles.

In a preferred embodiment of the present invention, at least one selected from the group consisting of a polyester resin, a polyurethane resin, and a polyacrylic resin on the side opposite to the surface having the ink receiving layer with respect to the base film. It has a coat layer containing one kind.

The present invention also provides an inkjet recording film in which the ink-receiving layer of the inkjet recording film described above has absorbed the inkjet recording ink. The present invention will be described in more detail below.

The ink jet recording film of the present invention has a base film and an ink receiving layer on at least one side of the base film.

The resin used for the base film used in the present invention is not particularly limited, and known synthetic resins can be used. In particular, it is preferable to use polyester from the viewpoint of improving the adhesiveness and suppressing the production cost. Among the known resins, polyolefin cannot be thinned because it is not stiff, and further, the substrate film obtained by this has poor adhesiveness with the ink receiving layer described below, Since it is difficult to provide the ink receiving layer on the material film, it cannot be said to be suitable.

The above polyester includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid or esters thereof, ethylene glycol,
It is produced by polycondensation with glycols such as diethylene glycol, 1,4-butanediol and neopentyl glycol. These polyesters include a method of directly reacting an aromatic dicarboxylic acid and a glycol, a method of transesterifying an alkyl ester of an aromatic dicarboxylic acid and a glycol and then polycondensing, or a diglycol ester of an aromatic dicarboxylic acid. It is produced by a method such as polycondensation. Typical examples of such polyesters include polyethylene terephthalate, polyethylene butylene terephthalate, polyethylene-2,6.
-Naphthalate and the like. This polyester may be a homopolyester containing one type of aromatic dicarboxylic acid and one glycol, or may be a copolyester containing two or more types of aromatic dicarboxylic acid and / or glycol. Alternatively, the copolymerized polyester may further contain a dicarboxylic acid other than the aromatic dicarboxylic acid. The polyester of the present invention contains 7 units of ethylene terephthalate units, butylene terephthalate units, or ethylene-2,6-naphthalate units.
The content is preferably 0 mol% or more, more preferably 80 mol% or more, and most preferably 90 mol% or more.

The base film used in the present invention contains a large number of cavities inside. This cavity has a ratio L / T of the average length L of the cavities present in the cut surface when cut in one direction perpendicular to the surface of the base film and the average T of the cavity thickness. It is 7.0 or more, preferably 10.
It is 0 or more, and most preferably 13.0 or more. When L / T is less than 7.0, wrinkles or curls are likely to occur during printing. The term "cavity" as used herein refers to a space in the substrate film that is developed by the cavity-developing agent described below, and for example, a space that is expressed by inorganic particles or the like is excluded. The average length L of the cavities and the average thickness T of the cavities are the length L _n (n = 1,2,3 ...) And the thickness T _{n of} each cavity present in any cut surface of the film. (n = 1,2,3
() Is the average value of each.

When the base film is cut perpendicularly to the surface of the base film, a plurality of cavities are present on the cut surface. The cavities on the cut surface may or may not be present on the cut surface depending on the cut site.

When the cavity of the cut surface contains the cavity developing agent, as shown in FIG. 1, L _n (eg, L ₁ ) is the cavity developing agent from the end of the cavity on the long axis of the cross section of the cavity. Up to. When the cavity developing agent is not present in the cross section of the cavity, the length of the cross section of the cavity is from the long axis to the end. T _n (T ₁ , T ₂ ...) Is the length of the cross-sectional portion of each cavity.

Further, the base film used in the present invention has the number of cavities n of 30 / 2,500 μm ² or more. If the cavities in the base film have L / T of 7.0 or more and the number of cavities n is less than 30 / 2,500 μm ² , the specific gravity of the obtained inkjet recording film does not decrease, The cushioning property is also lost. In this way, the film for inkjet recording of the present invention obtained by balancing the ratio (L / T) of the average value of the length of the cavities and the average value of the thickness and the number n of the cavities in the base film is , Wrinkles and curls do not occur during printing.

In order to develop the above-mentioned cavities in the substrate film, the substrate resin is mixed with a cavity-developing agent and, if necessary, a dispersible resin and other additives, and the resulting mixture is subjected to an ordinary method. To form a film and then orient the film at least uniaxially.

The cavity-developing agent used in the present invention is a thermoplastic resin which is incompatible with the resin constituting the base material such as polyester. Examples of such a cavity developing agent include polystyrene resin, polyolefin resin, polyacrylic resin, polycarbonate resin, polysulfone resin, and cellulose resin. In particular,
Polystyrene resin and polymethylpentene, from the viewpoint of improving the cavity expression and suppressing the production cost.
It is preferable to use at least one polyolefin resin such as polypropylene.

The amount of cavity-developing agent mixed with the base resin is
Depending on the number of cavities desired, 3% to 39% by weight, based on the weight of the substrate film, is preferred, especially 5
-30% by weight is preferred. When it is less than 3% by weight, the number of voids generated is small, and a void-containing film excellent in flexibility, lightness and drawability cannot be obtained. When it is 40% by weight or more, the heat resistance of polyester or the strength such as waist strength is significantly impaired.

The base film used in the present invention is, in addition to the base resin and the cavity-developing agent, a polymer compound (hereinafter referred to as a dispersible resin in order to distinguish it from the cavity-developing agent).
Are preferably mixed. The dispersible resin has a higher surface tension (surface energy) than that of the void-developing agent and uniformly disperses the void-developing agent in the substrate film. Such a dispersible resin differs depending on the type of resin and the cavity developing agent that are the main components of the base film. For example, when using a polymethylpentene, polypropylene, a polyolefin resin such as a cyclic olefin polymer, a silicone resin or the like as the cavity developing agent, the dispersible resin is a polystyrene resin, a polycarbonate resin, a polyacrylic resin, a polyphenylene ether resin, Alternatively, a polyolefin resin or polystyrene resin modified with maleimide or carboxylic acid is used, and when a polystyrene resin is used as the cavity-developing agent, the dispersible resin is a polycarbonate resin, a polyacrylic resin, a polyphenylene ether resin, or a maleimide or a carboxylic acid resin. An acid-modified polyolefin resin or polystyrene resin is used.

By adding a small amount of such a dispersible resin to the base film, the effect as a dispersant for the cavity developing agent can be obtained. The content of the dispersible resin in the base film is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, relative to 100 parts by weight of the cavity-developing agent contained in the film. Addition amount of dispersible resin is 20
When it exceeds the weight part, the void developing agent in the base film becomes fine, but at the same time, the void developing ability in the base film is lowered.

In the present invention, it is preferable in the present invention to increase the content of the above-mentioned void-developing agent and disperse it more finely with a dispersible resin to form a large number of voids.

The base film used in the present invention may further be mixed with a light-shielding agent, various additives and the like. The particles are used for improving the hiding rate and drawability of the film, and include titanium dioxide, silicon dioxide, calcium carbonate, barium sulfate, aluminum oxide, zeolite, kaolin,
Examples thereof include inorganic particles such as talc, but are not particularly limited thereto. As the additive, a colorant, a light-proofing agent, a fluorescent agent, an antistatic agent, or the like is used depending on the application. These particles and additives can be added in amounts known to those skilled in the art.

The resin forming the base material and the cavity developing agent are mixed by the following method, for example, to form a film. (1) Resin for base material, cavity developing agent and optionally a light-shielding agent, various additives, etc. are mixed and extruded and solidified while being melt-kneaded in an extruder, (2) Resin for base material and cavity A method of melt-kneading each of the expression agents, mixing the kneaded product in an extruder, and solidifying by extrusion, or
(3) A method in which a cavity-developing agent is added when preparing a resin for a substrate and the chips obtained by dispersing by stirring are melt-extruded and solidified.

The obtained unstretched film is usually a non-oriented or weakly oriented film, and the void-developing agent is dispersed in the base resin in various shapes such as spherical, elliptic spherical, or thread-like. Exists.

Further, the base film used in the present invention may be a single layer or a composite film in which two or more central layers (A) and surface layers (B) are laminated. In the central layer (A), the base resin and the cavity developing agent, and if necessary, the particles, various additives and the like are mixed and used. The surface layer (B) may or may not contain a cavity developing agent. The base film comprising the central layer (A) containing such a void-developing agent and the surface layer (B) containing no void-developing agent has advantages such as improving the strength of the film surface. The base resin used for the central layer and the surface layer is preferably the above polyester.

The method of laminating the central layer and the surface layer is not particularly limited. However, from the viewpoint of improving productivity, the co-extrusion method in which each material used for the surface layer and the center layer is extruded from different extruders and then they are introduced into one die to form an unstretched film. Most preferred.

The unstretched film is formed into a film oriented in at least a uniaxial direction through processes such as roll stretching, tenter stretching, and inflation stretching. The base film in the present invention is particularly the most general sequential biaxial stretching method in which a continuous sheet of an unstretched film is roll-stretched (longitudinal stretch) in the longitudinal direction and then tenter-stretched (transversely stretched) in the width direction. It is preferable to mold after that.

In the above-mentioned manufacturing method, in the first longitudinal stretching step, the film can be stretched by using two or more rolls having different peripheral speeds. As the heating means at this time, a method using a heating roll, a method of performing non-contact heating, or a method of using them in combination can be used.

The heating temperature in the longitudinal stretching step in the present invention is
When polyethylene terephthalate is used, 70 ° C. to 120 ° C., preferably 80 ° C. to 10 ° C., because the second-order transition temperature of the polyethylene terephthalate is 70 ° C. or lower.
It is in the range of 0 ° C., and the longitudinal stretching ratio is in the range of 1.5 to 4.0, preferably 2.5 to 3.7.

Further, after this longitudinal stretching step, any relaxation treatment can be carried out.

In the present invention, the transverse stretching process is performed in the following two stages.

The first step of transverse stretching is carried out in order to develop sufficient cavities in the base film. The heating temperature at this time is 100 ° C to 150 ° C, preferably 105 ° C to
150 ° C., and the transverse draw ratio is 2.0 to 3.
5, preferably 2.0 to 3.0.

The second stage of the transverse stretching process is carried out in order to thin the film and obtain cavities which are evenly balanced in the machine and transverse directions, and the number of cavities hardly increases. The heating temperature at this time is 180 ° C. to 230 ° C., preferably 185 ° C. to 225 ° C., and the transverse stretching ratio is 1.2 to 2.0, preferably 1.3 to 2.0. By the transverse stretching in the second stage, the total of the transverse stretching ratios in the first stage and the second stage may exceed the longitudinal stretching ratio.

The film thus obtained is relaxed by 2% to 5% in the (longitudinal and / or lateral) direction to give 2%
Thermal solidification is performed at a heat treatment temperature of 20 ° C. or higher, preferably 220 ° C. or higher, more preferably 230 ° C. or higher. The film has a heat shrinkage at 150 ° C. of less than 2%, preferably less than 1.7%, more preferably less than 1.5%. However, heat treatment temperatures below 220 ° C and /
Alternatively, if the longitudinal and / or transverse relaxation is less than 2%, a film having the above heat shrinkage cannot be obtained.

Under such a stretching condition, peeling occurs at the interface between the base resin and the void-developing agent, and a substrate film having a large number of voids is obtained.

On the other hand, for example, JP-A-63-16
8441, JP-A-63-193938,
JP-A-2-80247 and JP-A-2-28492
No. 9, JP-A No. 3-114817, and JP-A No. 4-202540 disclose a longitudinal stretching step of 80 in order to develop a large number of cavities in the substrate film.
A heating temperature of 80 ° C. to 100 ° C. and a longitudinal stretching ratio of 2.0 to 5.0; and a transverse stretching step, a heating temperature of 80 ° C. to 140 ° C. and a lateral stretching ratio of 2.8 to 5.0 are used. Further, it is described that the heat treatment after stretching is performed at 150 ° C. or higher.

However, under such stretching conditions, the ratio of the length and the thickness of the cavities to be developed tends to be small, and the film tends to cause wrinkles and curls in the printer. One of the reasons for this is that cavities elongated in the stretching direction are not formed due to the low temperature during transverse stretching. Polyolefin resins such as polymethylpentene and polypropylene, and polystyrene resins have a glass transition temperature of 100 ° C. or lower, and therefore are deformed and crushed by tenter stretching. As described above, at a heating temperature of 140 ° C. or less, it is difficult to obtain a sufficiently deformed cavity that is thin enough to reach the object of the present invention.

The ink receiving layer used in the present invention is not particularly limited as long as it has an affinity for the ink.
For example, polyvinyl alcohol, acrylic resin, styrene-acrylic polymer, ethylene-vinyl acetate polymer, starch, polyvinyl butyral, gelatin, casein,
Ionomer, gum arabic, carboxymethyl cellulose, polyvinylpyrrolidone, polyacrylamide, polyester resin, phenol, melanin resin, epoxy resin, styrene-butadiene rubber and the like can be used. These can be used as a mixture of at least one kind. Furthermore, for the ink receiving layer, melamine resin, epoxy resin,
Inclusion of an isocyanate group-containing polyurethane resin or the like can improve the curing degree and water resistance of the ink receiving layer. Further, preferably in order to form a slipping layer and the like, silica, kaolinite, talc, calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, titanium oxide, organic white pigment, benzoguanamine particles, crosslinked polystyrene, Particles such as crosslinked acrylic particles and aluminum hydroxide may be included in the ink receiving layer.

The ink receiving layer can be one layer or a composite layer of two or more layers.

By providing an easy-adhesion layer between the base film and the receiving layer, the adhesiveness between the base film and the receiving layer can be improved. As the main component constituting the easy-adhesion layer, a polyester-based resin is preferable, but in addition to this, a resin known to those skilled in the art as a means for improving the adhesiveness with an ordinary polyester film, for example, a polyurethane resin or polyester urethane. Resin, acrylic resin, etc. may be used.
Further, a melamine resin, a crosslinking agent such as an isocyanate group-containing polyurethane resin, or silica, kaolinite, talc, calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, titanium oxide, organic white pigments, benzoguatemine particles, crosslinking Particles such as polystyrene, crosslinked acrylic particles, and aluminum hydroxide may be included in the easy-adhesion layer.

As a method of applying the ink receiving layer and the easy adhesion layer, a gravure coating method, a kiss coating method, a dipping method, a spray coating method, a curtain coating method, an air knife coating method, a blade coating method,
Various coating methods such as a reverse roll coating method can be used. The formation of these layers can be carried out either before the stretching of the film, after the longitudinal stretching, or after the completion of all the stretching treatments.

Further, in order to improve the transportability inside the printer and to improve the pencil drawing property of the back surface, particles, an antistatic agent and a binder are provided on the surface of the base film opposite to the surface having the ink receiving layer. It is possible to form a coat layer (easy-slip layer) containing the above. As the main component that constitutes this layer, polyester resins, polyurethane resins, polyester urethane resins, and acrylic resins are preferable, but resins known to those skilled in the art as means for improving the adhesiveness of ordinary base films may also be used. Can be used. Among these resins, for example, epoxy resins, melamine resins, crosslinking agents such as isocyanate group-containing polyurethane resins, as well as silica, kaolinite, talc, calcium carbonate,
Organic and inorganic particles such as zeolite, alumina, barium sulfate, carbon black, zinc oxide, titanium oxide, organic white pigments, benzoguatemine particles, crosslinked polystyrene, crosslinked acrylic particles, aluminum hydroxide may be added. In particular, by adding particles having an average particle diameter of 1.0 μm, the drawability in the coat layer is improved.

Various methods such as a gravure coating method, a kiss coating method, a dipping method, a splay coating method, a curtain coating method, an air knife coating method, a blade coating method and a reverse roll coating method are used as a method for applying the above-mentioned coating layer. You can The coat layer is (1)
A method of preliminarily imparting to the surface of the mixed polymer before the orientation treatment; (2) a method of stretching in the uniaxial direction, then imparting to the film surface, and then stretching it in the perpendicular direction;
(3) A method of applying to the film surface after the orientation treatment.

The apparent specific gravity of the film thus obtained is 0.6 or more and 1.3 or less, preferably 0.8 or more and 1.3 or less, and more preferably 1.05 or more and 1.
It is 25 or less. If the apparent specific gravity is less than 0.6, the void content is too large, so that the strength of the base film is impaired, and wrinkles and curls due to heat occur. If the apparent specific gravity exceeds 1.3, the drawability, printability, and thermal recording property of the film will be poor.

In this way, the size of the internal cavity is optimized as compared with the conventional film, the ink is absorbed promptly, the surface has a drawing property for a pencil, and wrinkles are generated in the printer. A recording film suitable for a difficult inkjet printer can be obtained.

[0051]

EXAMPLES The ink jet recording film of the present invention will be described below with reference to Examples and Comparative Examples.

The measurement / evaluation methods used in the present invention are shown below.

(1) Intrinsic Viscosity of Polyester The intrinsic viscosity of polyester was dissolved in a mixed solvent of phenol (6 parts by weight) and tetrachloroethane (4 parts by weight) and measured at 30 ° C.

(2) Apparent Specific Gravity The thickness of a square film having a size of 5.00 cm × 5.00 cm is measured at 50 points, and the average value is taken as t μm. On the other hand, the weight of the film is measured with an accuracy of 0.1 mg to obtain wg. Then, the apparent specific gravity was calculated by the following formula.

[0055]

[Equation 1]

(3) Average value of cavity length L1 and average value of thickness T1 The vicinity of the surface layer of the film was photographed with a scanning microscope at a magnification of 2000, and the cavity was traced on a tracing film and painted. Was subjected to image processing with an image analyzer, and the length L _n and the thickness T _n of the cavity were measured. At this time, the cavities developed from the inorganic particles were ignored. -Scanning electron microscope used S-510 scanning electron microscope manufactured by Hitachi Ltd.-Image processing device used Seiko Epson Corp. Image Scanner GT-8
000 is used to import images into Adobe Photoshop TM2.5J, a personal computer Macintosh software, and the software, Ultimage TM / 242.1.
Image analysis was performed in 1.

(4) Number of cavities n The number of cavities contained in 25 μm in thickness × 100 μm in length in the central portion of the photograph of the cut surface of the substrate film taken in (3) was counted.

(5) Initial elastic modulus It was measured according to ASTM D-882-81 (method A).
For the sample, the stress was measured with respect to the measurement length at a chuck distance of 40 mm, a width of 10 mm, and a pulling speed of 200 mm / min, and the stress was determined from the substantially directly proportional portion immediately after the start of pulling.

(6) Heat shrinkage rate A film having a width of 10 mm and a length of 250 mm is marked at intervals of 200 mm in the length direction, both ends of the film are fixed in the length direction, and the film is printed under a constant tension of 5 g. The interval A was measured. Subsequently, the tension was released, and the mark interval B was determined after the plate was placed in an oven in an atmosphere of 150 ° C. for 30 minutes. Then, the heat shrinkage rate was calculated by the following formula.

[0060]

[Equation 2]

(7) Light transmittance According to JIS-K6714, the Poick integrating sphere type H. T.
The light transmittance of the film was measured using an R meter (manufactured by Nippon Seimitsu Optical Co., Ltd.). The smaller this value, the higher the hiding power of the film.

(8) Presence or absence of wrinkles on the printer. Using an inkjet printer (HP650C), a drawing was printed on the A1 plate film. At this time, when wrinkles did not occur, it was rated as O, and when wrinkles occurred, it was rated as X.

(9) Printability If the printing of the drawing according to (8) is good, the mark is ◯, and if unevenness, defects, etc. are generated and the aesthetics are impaired, the mark is marked.

(Example 1) 75% by weight of polyethylene terephthalate resin having an intrinsic viscosity of 0.62 and 2 parts of general-purpose polystyrene resin (T575-57U manufactured by Mitsui Toatsu Chemicals, Inc.)
0% by weight, maleimide-modified polystyrene resin (NH1200 manufactured by Mitsui Toatsu Chemicals, Inc.) 1% by weight, average particle size 0.3
5 μm anatase type titanium dioxide (Fuji Titanium Co., Ltd.)
TA-300) 3 wt% of the mixture is supplied to a twin screw extruder, melt-extruded from a T-die at 290 ° C., electrostatically adhered to a cooling rotary roll to solidify, and an unstretched film of about 1100 μm. Got

This unstretched film was introduced into a roll stretching machine and subjected to an orientation treatment at a heating temperature of 80 ° C. and a longitudinal stretching ratio of 3.1. Then, orientation treatment was carried out in a tenter at a heating temperature of 125 ° C. and a transverse stretching ratio of 2.7, and subsequently in a tenter at a heating temperature of 220 ° C. and a transverse stretching ratio of 1.5. Then, it was heat-treated at 235 ° C. while being relaxed in the lateral direction by 4% to obtain a polyester film having a large number of cavities in the base film.

On both sides of this film, 2% by weight of a copolyester resin (Vylon MD-16 manufactured by Toyobo Co., Ltd.), 2% by weight of an isocyanate-containing polyurethane resin (Elastron H-3 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and an average particle diameter of About 0.8% by weight of 2.5 μm spherical silica particles was mixed with a mixed solution of water and isopropyl alcohol having a weight ratio of 7/3, and the mixture was applied with a wire bar (# 5). afterwards,
The film was dried at 80 ° C for 2 minutes and dried at 170 ° C for 30 seconds.

On one side of this film, 20 parts by weight of polyvinyl alcohol (PVA117 manufactured by Kuraray Co., Ltd.) and 10% by weight of an isocyanate-containing polyurethane resin (Elastron BN-08 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 230 parts by weight of water. The PVA solution obtained as described above was applied with a wire bar so that the PVA solution after drying was 10 g / m ² to obtain an inkjet recording film having a thickness of about 50 μm. Table 1 shows the evaluation results of the obtained film.

(Examples 2, 3, 4 and 5) Crystalline polypropylene resin (Mitsui Toatsu Chemical Co., Ltd.) as a cavity developing agent.
FO-50F manufactured by Mitsui Chemicals, cyclic olefin resin (Apel APL6011 manufactured by Mitsui Petrochemical Co., Ltd.), polymethylpentene resin (RT-18 manufactured by Mitsui Petrochemical Co., Ltd.), and general-purpose polystyrene resin (Mitsui Higashi) as a dispersible resin. An ink jet recording film was obtained in the same manner as in Example 1 except that T575-57U manufactured by Pressure Chemical Co., Ltd.) and titanium dioxide were added in the proportions shown in Table 1. Table 1 shows the evaluation results of the obtained film.

(Example 6) The same material as in Example 3 was used for the A layer, 98% by weight of polyethylene terephthalate resin having an intrinsic viscosity of 0.62 was used for the B layer, and spherical zeolite particles (JC manufactured by Mizusawa Chemical Co., Ltd.). -20) Using 2% by weight, the materials of layer A and layer B were introduced into separate twin-screw extruders, kneaded, and laminated in the order of B / A / B in a T-die, and then extruded. Then, using the same method as in Example 1 except that the unstretched film was obtained by electrostatically adhering to the cooling roll, the thickness of each of the A layer and the B layer was 45.
Films for inkjet recording having a thickness of 5 μm and 5 μm were obtained. Table 1 shows the evaluation results of the obtained film.

(Example 7) The same material as in Example 5 was used for the A layer, and 90% by weight of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62 and an average particle size of 0.6 for the B layer.
An inkjet recording film was obtained in the same manner as in Example 6, except that 10% by weight of calcium carbonate having a thickness of 10 μm was used. Table 1 shows the evaluation results of the obtained film.

Comparative Example 1 An ink jet recording film was obtained in the same manner as in Example 3 except that the heating temperature in the transverse stretching step in Example 3 was 125 ° C. and the heating was performed only once. Table 2 shows the evaluation results of the obtained film.

(Comparative Example 2) The same as Example 3 except that 0.5% by weight of a silicon-based surfactant (SH193 manufactured by Toray Silicone Co., Ltd.) was used in place of general-purpose polystyrene. An ink jet recording film was obtained by the method.

In this film, the coat layer could not be applied uniformly, and many repellings occurred, and as a result, many defects were found in printing with a printer. Table 2 shows the evaluation results of the obtained film.

Comparative Example 3 The same as Example 3 except that 0.5 wt% of polyethylene glycol having a molecular weight of 4000 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used in place of polystyrene for general use. An ink jet recording film was obtained by the method. Table 2 shows the evaluation results of the obtained film.
Shown in

(Comparative Example 4) An ink jet recording film was obtained in the same manner as in Example 3, except that the amount of the general-purpose polystyrene resin added was changed to 0% by weight. Table 2 shows the evaluation results of the obtained film.

(Comparative Example 5) An ink jet recording film was obtained in the same manner as in Example 3 except that the addition amount of the general-purpose polystyrene resin was changed to 5% by weight. Table 2 shows the evaluation results of the obtained film.

[0077]

[Table 1]

[0078]

[Table 2]

As can be seen from Tables 1 and 2, the films obtained in Examples 1 to 7 were superior to the films of Comparative Examples 1 to 5 in all evaluation items.

[0080]

According to the present invention, by optimizing the size of the cavities in the base film, the ink can be absorbed promptly and the drawability of the film surface can be improved, and an ink jet printer, particularly a large size printer, can be used. To provide a film for inkjet recording, which prevents wrinkles and curls from being generated at the time of printing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cavity containing a cavity developing agent.

[Explanation of symbols]

 1. Cavity developing agent 2. cavity

Claims (6)

[Claims] 1. An ink jet recording film having an ink receiving layer on at least one side of a base film, the base film having a cavity therein, and being perpendicular to the surface of the base film. The ratio L / T of the average length L of the cavities present on the cut surface and the average thickness T of the cavities when cut in one direction is 7.0 or more, and the cavities contained in the base film Number n is 30/25
00 μm ² or more, and the overall apparent specific gravity is 0.
An inkjet recording film having a thickness of 6 or more and 1.3 or less. 2. The base film is a film having fine voids obtained by orienting at least uniaxially a polymer mixture containing polyester and a thermoplastic resin incompatible with the polyester. , Claim 1
The ink jet recording film according to. 3. An easy-adhesion layer and an ink receiving layer are sequentially provided on at least one surface of the base film, and the easy-adhesion layer comprises at least one selected from a polyester resin, a polyacrylic resin, and a polyurethane resin. The ink jet recording film according to claim 1 or 2, which is contained. 4. The film according to claim 3, wherein the easy-adhesion layer and / or the ink-receiving layer contains particles. 5. A coating layer containing at least one selected from the group consisting of a polyester resin, a polyurethane resin, and a polyacrylic resin on the side opposite to the surface having the ink receiving layer with respect to the base film. The film according to any one of claims 1 to 4, which comprises: 6. An inkjet recording film, comprising:
A film, wherein the ink-jet recording ink is absorbed in the ink receiving layer of the ink-jet recording film according to any one of claims 1 to 5.