JPH0885181A - Film having absorbing property and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide with both of surface flatness and absorbing capacity for ink and the like by a method wherein irregular crater type film surfaces, having a specified value of diameter, are formed on at least one side surface while an absorbing layer, consisting of fibrous porous layer, is formed in a film. CONSTITUTION: A film having absorbing property can be obtained by laminating an unoriented resin sheet and an unoriented fiber web, made by hot pressing, then, orienting together to form an absorbing layer on at least one side of a supporting body film. In the absorbing layer, a single or a multiple layers of unoriented fiber webs are pressed through hot pressing by a heat calender and the like whereby fibers, constituting the web, are bonded forcibly with each other at the entanglement points thereof. The unoriented fiber web, pressed through hot pressing, is oriented whereby not only the fibers but also the entanglement part of the fibers, bonded through hot pressing, are oriented and irregular crater type film surfaces, having diameters of 0.1-50μm, are formed on the surface of the unoriented fiber web while fibrous porous layers are formed in the web. Further, the crater type film surfaces and the fibrous porous layers are communicated through ultra-fine through holes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorptive film having excellent surface smoothness and glossiness and a method for producing the same. More specifically, paper substitutes such as cards, labels, stickers, image receiving paper for video printers, image receiving paper for barcodes, posters, maps, dust-free paper, display boards, white boards, photographic papers, copy papers, etc. The present invention relates to an absorbent film suitable as a printing sheet such as an offset printing receiving sheet, a melt transfer type thermal transfer receiving sheet, and an inkjet receiving sheet, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a receiving sheet used for offset printing, ink jet recording or the like is required to have ink solvent absorbability and molten ink impregnation property, and films and sheets for these purposes have been proposed.

For example, a heat-sensitive transfer image receptor made of a fine bubble-containing polyester film (JP-A-1-168493), a laminated film in which a polyester film having a density of 1.3 or more is laminated on at least one side of the fine bubble-containing polyester film ( Japanese Patent Application Laid-Open No. 2-80247),
There is a heat-sensitive transfer sheet (Japanese Patent Application Laid-Open No. 2-81678) in which films having different bubble contents are laminated.

As a sheet having a porous layer on its surface, a recording sheet having an ink-receiving layer on a support and having a pore size distribution of two peaks in the receiving layer (Japanese Patent Publication No. 63-22997). (Patent document), a recording material for inkjet (Japanese Patent Publication No. 63-56876) having a continuous coating layer having pores as a receiving layer is known.

As a printing sheet using a non-woven fabric as a base material,
A non-woven fabric sheet for printing in which an ink adhesion layer made of an acrylic resin is provided on at least one side of the non-woven fabric (JP-A-3-23).
No. 4869) has been proposed.

Further, as a laminate of a fibrous substance and a plastic, a cellulosic thin paper is laminated on one surface of a thermoplastic resin, and the composite paper-like structure is bonded to each other by the thermoplastic resin having a fine porous structure (Japanese Patent Laid-Open No. -138077 publication)
There is.

[0007]

However, in the above-mentioned conventional techniques, the absorptivity which is an important function as a receptor, that is, the absorptivity of ink solvent such as offset printing and ink jet printing, and the melted ink of thermal transfer material The impregnation property was not always satisfactory. If the ink solvent also has insufficient absorptivity, the sheet surface after printing will be insufficiently dried, and show-through will occur due to overlaying, and a clear image cannot be obtained. Further, in the thermal transfer application, if the impregnation of the molten ink is insufficient, the ink layer will be swelled on the surface, resulting in insufficient abrasion resistance.

That is, it is desirable to have a receiving sheet in which the absorption of the ink solvent and the impregnation of the molten ink are carried out more quickly and completely.

Further, an important characteristic as a receptor is surface smoothness, and it was necessary to satisfy both surface smoothness and absorbability at the same time.

[0010]

SUMMARY OF THE INVENTION The present invention provides a film having a specific structure in order to meet the above demands. That is, at least one surface has a diameter of 0.1 to 5
The skeleton of an absorbent film is characterized in that an irregular crater-like film surface of 00 μm is formed and an absorbent layer made of a fibrous porous layer is formed inside. Further, as another preferred embodiment, a layer formed by forming an irregular crater-like membrane surface having a diameter of 0.1 to 500 μm on at least one surface and forming an absorbent layer made of a fibrous porous layer inside thereof And an absorbent film provided on at least one side of a support film.

The absorbent film according to the present invention has an irregular crater-like film surface formed on at least one surface. That is, by forming a crater film surface,
It is possible to obtain surface smoothness and glossiness suitable as a print receiver. The crater has a diameter in the range of 0.1 to 500 μm, preferably 0.1 to 500 μm.
It is in the range of 300 μm, more preferably 0.1 to 100 μm. If the diameter is less than 0.1 μm, the structure of the film surface becomes too dense, and the absorbency tends to decrease. Further, if the diameter exceeds 500 μm, the smoothness and glossiness of the surface tend to decrease. The diameter of the crater in the present invention means an equivalent circular diameter.

The absorbent film of the present invention has a very fine through hole on the inside of the crater-like film formed on the surface thereof, and has a function of allowing the liquid to permeate into the inside through this hole.

The absorbent film of the present invention has an absorbent layer formed of a fibrous porous layer formed inside. That is, by forming a fibrous porous layer, a fiber layer having a large number of continuous voids effectively acts as a trap layer, it becomes possible to have a structure having a so-called bottle structure,
It is extremely effective as a receiving layer.

In the absorbent film of the present invention, the absorbent layer comprising a fibrous porous layer preferably has a pore volume (Vp) of 0.3 cm ³ / cm ³ or less and a specific surface area (S) of 1 m ^2.
/ Cm ³ or less, more preferably the pore volume is 0.2 cm
³ / cm ³ or less, and the specific surface area is 0.8 m ² / cm ³ or less. By setting the pore volume to 0.3 cm ³ / cm ³ or less and the specific surface area to 1 m ² / cm ³ or less, a denser absorption layer can be formed and an absorbent film suitable as a receptor can be obtained. Can be done. Pore volume is 0.
3 cm ³ / cm @ ^3, the specific surface area is more than 1 m ² / cm ^3, although accepting the ink is increased, it may become print quality is degraded ink tends bleeding.

The pore volume (V
The p) and the specific surface area (S) are values measured using a porosimeter 2000 manufactured by Carlo Erba Co., Ltd., and were measured as follows.

A sample (4 cm × 10 cm) was placed in the cell,
Mercury was injected under a reduced pressure of about 10 ⁻³ Torr, and this was mounted in an autoclave to apply hydrostatic pressure (P) to electrically detect the volume (Vp) of mercury injected into the pores of the sample. I asked. Each characteristic value is defined as follows.

Pore volume (Vp): Cumulative volume of press-fitted mercury of measured pore radius / Sample volume (cm ³ / cm ³ ) Specific surface area (S): Assuming cylindrical pores based on pore volume V Calculated specific surface area (m ² / cm ³ ), sample volume (Vs) = W / ρ (cm ³ ), where W is sample weight (g) and ρ is apparent density (g /
cm ³ ).

The apparent density of the absorbent layer of the absorbent film of the present invention is preferably less than 1.0 g / cm ³ , more preferably 0.1 g / cm ³ or more and less than 0.8 g / cm ³ , and even more preferably 0. 0.1 g / cm ³ or more 0.6 g
/ Cm ^{3 or} less.

The average surface roughness (Ra) of the absorbent film of the present invention is preferably 5 μm or less, more preferably 3 μm or less. If the average surface roughness exceeds 5 μm, the printing quality tends to deteriorate.

The glossiness of the absorbent film of the present invention is 10%.
The above is preferable. If the gloss level is less than 10%, the sharpness of printing tends to decrease.

A conventionally known thermoplastic resin is used for the absorbent film in the present invention. For example, polyester, polypropylene, polyethylene, polyamide, polyphenylene sulphide, etc. may be mentioned.

In the present invention, these may be used alone, two or more kinds may be mixed and used, or a copolymer may be used. Among them, polyester and its copolymer resin are preferably used in terms of heat resistance.

The polyester used in the present invention is a polymer obtained by polycondensation from a diol component and a dicarboxylic acid component, and the dicarboxylic acid component is terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacine. Typical examples thereof include acids, and examples of the diol component include typical examples of ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexanedimethanol, and the like. Of course, these polyesters may be homopolymers or copolymers of two or more dicarboxylic acid components or diol components. Copolymer components other than those mentioned above include diol components such as diethylene glycol, neopentyl glycol and polyalkylene glycol, 4,4-diphenyl ether dicarboxylic acid, hexahydroterephthalic acid, and ε.
Examples thereof include carboxylic acids such as oxycaproic acid, trimellitic acid, pyromellitic acid, and 5-sodium sulfoisophthalic acid. Specifically, for example, polyethylene terephthalate, polybutylene terephthalate, poly-1,
4-cyclohexane dimethylene terephthalate, polyethylene-2,6-naphthalate, etc. are mentioned.

In these polyesters, known additives such as heat resistance stabilizers, antioxidants, weather resistance agents, UV absorbers,
Organic and inorganic lubricants and fine particles, pigments, dyes, fillers, antistatic agents, nucleating agents and the like may be added.

The support film in the present invention is not particularly limited, and a conventionally known thermoplastic resin film is used, among which a polyester film is preferably used.

The polyester film may be transparent or opaque, but when used as a receiving sheet, an opaque polyester film, particularly one having excellent whiteness (for example, whiteness of 70% or more), improves the sharpness of the image after printing. Therefore, it is more preferable. The whitening of the polyester film can be obtained by a conventional method of adding inorganic particles such as titanium oxide. When it is applied to a receiving sheet, it is preferably soft and rich in cushioning property. Such a polyester film can be achieved by containing fine air bubbles inside, and the whiteness can be improved by the light scattering of the air bubbles. Is improved. Furthermore, the inclusion of air bubbles makes it possible to reduce the specific gravity.

The thickness of the support film in the present invention is not particularly limited, but when it is used as a printing receiving sheet such as an offset printing sheet, a heat-sensitive transfer receiving sheet or an inkjet receiving sheet, it is preferably 30 to 800 μm, and further, The thickness is preferably 50 to 500 μm.

In the absorbent film of the present invention, the thickness of the fibrous porous layer provided on the support film is preferably 1 μm or more, more preferably 3 μm.
That is all. When the thickness is less than 1 μm, it is not desirable in terms of absorption function.

Next, the method for producing the absorbent film of the present invention will be described, but the present invention is not limited to such an example.

Polyester chips, preferably polyethylene terephthalate having an intrinsic viscosity of 0.45 or more, are sufficiently vacuum-dried and then spun by a known direct melt-spinning method such as melt-blowing, spunbonding or flash spinning to obtain an unstretched fiber. Get the web.

For example, in the melt-blow spinning method, when the molten polymer is discharged from the spinneret, hot air is blown from the periphery of the spinneret to make the discharged polymer finer, and then on a net conveyor placed at an appropriate position. It is manufactured by spraying on and collecting it to form a web.
By appropriately selecting the polymer discharge amount, the hot air temperature, the hot air flow rate, and the conveyor moving speed, the fineness and basis weight of the unstretched fiber web can be arbitrarily set.

Similarly, in the spunbond method, the polymer discharged from the die is pulled by an air ejector, the obtained filament is collided with a collision plate to open the fiber, and the fiber is collected on a conveyor to form a web. Manufactured. By appropriately adjusting the air flow rate, the stretched orientation state of the filament can be arbitrarily set.

The fiber areal weight of the unstretched fiber web is not particularly limited, but usually 5 to 500 g / m ² is preferable. Although the fiber diameter is not particularly limited, it is usually preferably 0.1 to 30 μm. It may be a mixture of fibers having different fiber diameters. Also, the fibers may be continuous or discontinuous. It may be a mixture of continuous fibers and short fibers.

The crystallinity of an unstretched fibrous web is usually 20%.
The following is preferable, and 10% or less is more preferable.
The orientation degree of the unstretched fiber web is usually preferably 0.02 or less, more preferably 0.01 or less.

Next, in the present invention, it is essential that the unstretched fibrous webs thus obtained are laminated in a single layer or multiple layers and thermocompression bonded. The thermocompression bonding temperature is usually preferably between Tg and the melting point of the unstretched fiber web, and more preferably T.
It is preferably between g and Tg + 50 ° C. The method of thermocompression bonding is not particularly limited, but calender roll or double belt press is preferable from the viewpoint of uniform pressure bonding. In the case of a calendar roll, steel, paper, rubber, resin, etc. can be used as the roll material,
Usually, a combination of steel and a resin roll or steel and a paper roll is preferable. The number of roll stages is preferably two or more. The roll pressure during thermocompression bonding is 1 roll pressure.
It is preferably carried out in the range of 50 kg / cm. Thus, by thermocompressing the unstretched fiber web with a thermocalender or the like, the fibers constituting the web are forcibly bonded at the entanglement points, and the precursor essential to the present invention can be obtained. is there.

Next, in the present invention, it is essential to stretch the thermo-stretched unstretched fiber web. By stretching the unstretched fibrous web, not only the fibers but also the bonded portion of the thermocompression-bonded fibers are stretched, a crater-like membrane surface is formed on the surface of the unstretched fibrous web, and fibrous porous The quality layer is formed. Moreover, since the crater-like membrane surface and the fibrous porous layer are continuous by the extremely fine through-holes, the crater-like membrane surface and the fibrous porous layer can be impregnated with liquid or the like from the surface to the inside.

The stretching method is not particularly limited, but biaxial stretching is preferred in order to form a uniform crater membrane surface and a fibrous porous layer. Biaxial stretching may be either a sequential biaxial method or a simultaneous biaxial method. In the case of sequential biaxial stretching,
It is common to stretch in the longitudinal direction and then in the width direction,
Conversely, it may be stretched.

For example, when the unstretched fiber web is polyester, the unstretched web is guided to a roll group heated to 60 to 160 ° C. and stretched 1.5 to 10 times in the longitudinal direction. Subsequently, both ends of the stretched fibrous web are held by clips of a tenter and the width of the stretched fibrous web is 2 to 2
Stretch 8 times. Further, if necessary, 80 to 240 ° C
Then, the absorbent film of the present invention can be obtained by continuously heat-setting.

The thermocompression bonding of the fiber web may be carried out after the drawing, not before the drawing. In order to improve the surface smoothness,
It may be performed both before and after stretching.

Further, for surface modification, the surface of the absorbent film may be subjected to corona discharge treatment or the like.

Further, an unstretched resin sheet extruded by a usual T-die method and a thermocompression-bonded unstretched fiber web are laminated and co-stretched with the above heating roll group and a tenter to obtain a support film. The absorbent film of the present invention having an absorbent layer formed on one surface can be obtained. In this case, the unstretched fibrous web and the unstretched resin sheet may be superposed and then thermocompression bonded. In addition, unstretched fiber webs may be laminated on both sides of the unstretched resin sheet, thermocompression-bonded, and then stretched.

The absorptive film thus obtained is suitably used for various recording media for printing such as offset printing receiving sheet, melt transfer type thermal transfer receiving sheet and ink jet receiving sheet. Also, cards, labels,
Stickers, image receiving paper for video printers, image receiving paper for barcodes, posters, maps, dust-free paper, display boards, white boards, photographic paper,
It is also suitably used as a printing substrate such as copy paper. Furthermore, it can be applied to applications such as dew condensation prevention sheets, agricultural sheets, packaging sheets, and oil-impregnated capacitors.

[0043]

[Characteristic Value Measuring Method and Effect Evaluation Method] Next, the characteristic value measuring method and effect evaluation method of the present invention will be described.

(1) Surface observation and measurement of crater diameter The surface of the sample was observed by a scanning electron microscope (Topcon DS13 Co., Ltd.).
In 0), the presence or absence of craters was confirmed by observing at a magnification of 300 times. In addition, the surface of the sample was photographed to measure the diameter of the crater.

(2) Thickness of absorption layer A cross section of the sample was taken by a scanning electron microscope (Topcon DS13 Co., Ltd.).
In 0), the thickness was measured by taking a photograph at a magnification of 1000 times.

(3) Surface roughness In accordance with JIS-B0601-1976, using a surface roughness meter manufactured by Kosaka, the center line average roughness Ra (μm) was measured at a cutoff of 0.8 mm and a measuring length of 8 mm in the longitudinal direction and the width direction. Asked about.

(4) Glossiness The glossiness of the surface was measured according to JIS-Z8741.

(5) Absorption rate-1 (offset printing) Printing suitability tester RI-3 tester (manufactured by Akira Seisakusho Co., Ltd.)
Was used to print Beni (Tohka Dye Co., Ltd.) for Arpo synthetic paper, which is an ink for offset printing, and the image sharpness was determined according to the following evaluation levels. The amount of ink applied was about 3 μm, and the absorption was evaluated by overlaying the coated surface of OK coated paper (Oji Paper Co., Ltd.) on the printed surface with a linear pressure of 353 g.
/ Cm of the metal roll was run, and the time (minute) until the ink was not transferred to the OK coated paper was measured by visual judgment. If the time was 15 minutes or less, it was determined that the absorbability was good.

(6) Absorption rate-2 (ink jet printing) 98 note personal computer manufactured by NEC Corporation
Bubble Jet Printer BJC- manufactured by Canon Inc.
820J was connected, a character pattern was inkjet-recorded, and the degree of contamination of the recording layer with the ink when the printed portion immediately after recording was rubbed once with a finger was judged according to the following criteria.

⊚: Very good (no stain due to the recording layer) ◯: Good visually, a little stain is seen with a magnifying glass Δ: Slightly scuffed stain x: Image is so stainable that it cannot be distinguished

(7) Image sharpness The image sharpness of the image obtained by the printing of the above (5) and (6) was visually judged according to the following criteria.

⊚: Very clear ○: Good Δ: Slightly blurred image (bleeding) is observed ×: Image is significantly blurred (bleeding)

[0053]

The present invention will be described in more detail based on the following examples.

Example 1 Polyethylene terephthalate (intrinsic viscosity [η] = 0.6
0) was melt-blow spun at a spinneret temperature of 285 ° C. using a rectangular spinneret having a hole diameter of 0.3 mm and 70 holes, and a basis weight 1
An unstretched fibrous web of 00 g / m ² was prepared. The average fiber diameter of the fiber web is 6.2 μm, the degree of orientation is 0.002,
The density was 1.336 g / cm ³ .

Next, five unstretched fibrous webs were superposed and passed through a calender roll heated to 100 ° C. alternately three times each on the front and back sides for thermocompression bonding. Roll linear pressure is 10kg / c
m.

Subsequently, the thermocompression bonded fiber web is passed through a roll-type stretching machine, stretched 3 times in the longitudinal direction at 90 ° C., and then stretched at 25 ° C.
Cooled to. Further, it was introduced into a tenter, stretched 3.5 times in the width direction in an atmosphere heated to 95 ° C., and heat-set at 200 ° C. to obtain an absorbent film having a thickness of 160 μm.

When the surface of the film was observed with a scanning electron microscope, an irregular crater-like film surface was formed on the surface.

Example 2 Polyethylene terephthalate (intrinsic viscosity [η] = 0.6
0) is melt spun and the speed is 1500m with an air ejector.
It was pulled at a speed of 1 / min and collected by cooling on a net conveyor to prepare an unstretched fiber web having a basis weight of 100 g / m ² . The average fiber diameter of the fiber web is 20 μm, the degree of orientation is 0.009,
The density was 1.340 g / cm ³ .

Next, four unstretched fibrous webs were stacked and 1
A calender roll heated to 10 ° C. was alternately passed through the front and back three times to perform thermocompression bonding. The roll linear pressure was 20 kg / cm.

Subsequently, the thermocompression-bonded fiber web was introduced into a roll-type stretching machine and a tenter and stretched under the same stretching conditions as in Example 1 to obtain an absorbent film having a thickness of 200 μm.

Observation of the surface of the film with a scanning electron microscope revealed that an irregular crater-like film surface was formed on the surface.

Example 3 Unstretched fibrous web (A) prepared in Example 1 and Example 2
The unstretched fiber web (B) prepared in 1. was prepared.

Then, three fiber webs were superposed in the order of A / B / A and passed through a calender roll heated to 95 ° C. alternately twice each on the front and back sides to be thermocompression bonded. Roll line pressure is 15k
It was set to g / cm. Subsequently, the thermocompression bonded fibrous web was subjected to 3.5 times in the longitudinal direction under the same temperature conditions as in Example 1 and 3.
The film was stretched 5 times and heat-set at 210 ° C. to obtain an absorbent film having a thickness of 110 μm.

When the surface of the film was observed with a scanning electron microscope, an irregular crater-like film surface was formed on the surface.

Example 4 Polyethylene terephthalate (intrinsic viscosity [η] = 0.6
5) 5% by weight, poly-4-methylpentene-1 (TPI-D820, Mitsui Petrochemical Co., Ltd.) 10% by weight, and 2% by weight of polyethylene glycol having a molecular weight of 4000 were mixed and the raw material was supplied to the extruder A. Then, it was melted at 285 ° C. by a conventional method and introduced into the central layer of the T-die three-layer composite die.

On the other hand, the above polyethylene terephthalate 9
0% by weight of calcium carbonate (average particle size 0.8 μm) 1
The raw material mixed with 0 wt% was supplied to an extruder B, melted at 285 ° C. by a conventional method and thinly laminated on both surface layers of a T-die three-layer die, and the melt sheet was kept at a surface temperature of 25 ° C. The thickness of 1.
A 6 mm unstretched polyester sheet was obtained.

Next, 100 g of areal weight produced in Example 1
/ M ² of unstretched polyester fiber web was passed through a calender roll heated to 85 ° C. alternately twice each on the front and back sides and thermocompression bonded. The roll linear pressure was 5 kg / cm.

Then, the unstretched polyester sheet and the thermocompression-bonded polyester fiber web are superposed and fed to a roll stretching machine, stretched 3.3 times in the longitudinal direction at 90 ° C., and 2
Cooled to 5 ° C. Then, it was introduced into a tenter, stretched 4 times in the width direction in an atmosphere heated to 95 ° C., and then heat-set at 225 ° C. while relaxing by 3% in the width direction to give a thickness of 1
An 80 μm composite film was obtained.

Observation of the nonwoven fabric side surface of the composite film with a scanning electron microscope revealed that an irregular crater-like film surface was formed on the surface.

As shown in Table 1, the evaluation results of the absorbent film thus obtained showed good absorption in offset printing and ink jet printing, and a clear image could be obtained.

Comparative Example 1 In Example 1, 5 unstretched fiber webs having a basis weight of 100 g / m ² were stacked and fed to a stretching machine without thermal compression using a calender roll. A stretched sheet having a length of 180 μm was obtained.

When the surface of the stretched sheet was observed with a scanning electron microscope, no irregular crater-like film surface was observed on the surface, and a reticulated surface in which fibers were irregularly entangled was formed.

Comparative Example 2 A composite film having a thickness of 180 μm was obtained in the same manner as in Example 4, except that the unstretched fibrous web was laminated with the unstretched polyester sheet without thermocompression bonding with a calender roll.

When the fiber web side of the film was observed with a scanning electron microscope, no irregular crater-like film surface was observed on the surface, and a mesh-like surface in which fibers were randomly entangled was formed.

As shown in Table 1, Comparative Examples 1 and 2 in which a crater-like film surface was not formed had good absorbability, but the printing was unclear and bleeding occurred.

[0076]

[Table 1]

[0077]

Industrial Applicability According to the present invention, an irregular crater-like membrane surface having a diameter of 0.1 to 500 μm is formed on at least one surface, and an absorbing layer composed of a fibrous porous layer is formed inside. The present invention relates to a featured absorbent film, which has a feature of having both surface smoothness and an ability to absorb ink and the like, and thus can provide a sharp image that is quickly dried in offset printing or inkjet printing.

Further, since it has characteristics such as glossiness, drawing property, and light-shielding property, it can be suitably used as a thermal transfer receptor, and further, it can be used as a dew condensation preventing sheet, an agricultural sheet, a packaging sheet, an oil-impregnated capacitor, etc. It can also be used for various purposes.

Claims (8)

[Claims] 1. A diameter of 0.1 to 50 on at least one surface.
An absorbent film having an irregular crater-like film surface of 0 μm and an absorbent layer made of a fibrous porous layer formed therein. 2. A diameter of 0.1 to 50 on at least one surface.
A layer formed by forming an irregular crater-like film surface of 0 μm and forming an absorption layer made of a fibrous porous layer inside,
An absorbent film provided on at least one surface of a support film. 3. The absorbent film according to claim 1, wherein the thickness of the absorbent layer is 1 μm or more. 4. The average surface roughness (R
a) is 5 micrometers or less, The absorptive film in any one of Claims 1-3 characterized by the above-mentioned. 5. The absorbent film according to any one of claims 1 to 4, wherein the crater-like film surface has a glossiness of 10% or more. 6. The absorbent film according to any one of claims 1 to 5, wherein the crater-like membrane surface and the fibrous porous layer are made of a resin mainly containing polyester. 7. A method for producing an absorbent film, which comprises thermocompressing an unstretched fiber web and then stretching. 8. A method for producing an absorbent film, which comprises laminating an unstretched film and a thermocompression-bonded unstretched fiber web, and then co-stretching.