JPH06297631A - Opaque composite film - Google Patents

Abstract

PURPOSE:To provide an opaque composite film having excellent softness, matting appearance of surface, and surface peel strength. CONSTITUTION:In a composite film, a film (B layer) containing inorganic powder is layered on one face or both faces of an opaque film (A layer) having a light transmission factor of 50% or less. Powder with circular shape or die shape or intermediate shape having irregularity on its surface is added to the B layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opaque composite film which has excellent matting properties and strong surface strength. More specifically, labels, stickers, posters, cards, recording paper, packaging materials, video printer image receiving paper, bar code labels, bar code printer image receiving paper, thermal transfer image receiving paper,
Thermal recording paper, image receiving paper for sublimation transfer, ink jet image receiving paper, offset printing paper, foam printing paper, map, dust-free paper, display board, white board, electronic white board, photographic paper, decorative paper, wallpaper, building materials, banknotes, release paper, Origami, calendar, magnetic cards, tracing paper, slips, delivery slips, pressure sensitive recording paper,
The present invention relates to an opaque composite film having a matte property suitable for base materials such as copy paper, clinical test paper, parabolic antenna reflector, and display reflector.

[0002]

2. Description of the Related Art Opaque films made mainly of synthetic resins are water resistant, moisture dimensional stability, gloss and sharpness of printing,
Due to its excellent mechanical strength, it is being used as a synthetic paper instead of paper.

Polyethylene, polypropylene, polyester, etc. are used as the main raw material of the opaque film. Among them, polyester represented by polyethylene terephthalate is excellent in that it has high heat resistance and is strong. A wide range of applications can be developed.

As a method for obtaining an opaque film containing polyester as a main raw material, there have been proposed methods such as adding inorganic particles having a concealing property to the film, or containing fine cavities inside the film.

However, the film obtained by these methods has a strong gloss on the film surface and is inferior in appearance as a paper substitute material, and it is necessary to roughen the surface in order to impart a matte property to the film. there were. Therefore, a method has been proposed in which particles having a large particle size such as calcium carbonate or silica are added to the film, or a film containing these particles is laminated on an opaque film to form a composite film.
However, the former method has problems that the stretchability of the film is poor and the mechanical strength of the film is significantly reduced. Further, in the latter method, the mechanical strength of the surface layer is reduced, and when the surface layer is used for an application such as a label by applying an adhesive treatment, the surface layer peels off when peeled off. there were.

[0006]

DISCLOSURE OF THE INVENTION The present invention has the drawback of the above-mentioned prior art, that is, it is extremely difficult to obtain an opaque film having excellent mechanical strength, high quality matte feeling and sufficient surface peeling strength. It is a solution.

[0007]

The present invention provides a composite film in which a film (B layer) containing inorganic particles is laminated on one or both sides of an opaque film (A layer) having a light transmittance of 50% or less. Further, the opaque composite film is characterized in that the layer B is added with particles having spherical or dice-like or intermediate shape having jagged irregularities on the surface.

Opaque film (A layer) in the present invention
The composition is not limited as long as it is mainly composed of a thermoplastic resin, but is preferably a film mainly composed of polyester. The polyester referred to here is an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid or an ester thereof and a glycol such as ethylene glycol, diethylene glycol, polyalkylene glycol, 1,4-butanediol or neopentyl glycol. It is a polyester produced by polycondensation. These polyesters include a method in which an aromatic dicarboxylic acid and a glycol are directly reacted, or an ester exchange reaction between an alkyl ester of an aromatic dicarboxylic acid and a glycol is followed by polycondensation or a diglycol of an aromatic dicarboxylic acid. It can be produced by a method such as polycondensing an ester.
Typical examples of such polyesters include polyethylene terephthalate, polybutylene terephthalate and polyethylene-2,6-naphthalate. This polyester may be a homopolymer or a copolymer of a third component. In any case, in the present invention, it is preferable to use a polyester having ethylene terephthalate units or ethylene-2,6-naphthalate units of 70 mol% or more, preferably 80 mol% or more.

The opaque film (A layer) of the present invention may be any one as long as it has a light transmittance of 50% or less. In order to set the light transmittance to 50% or less, a method of adding inorganic or organic particles capable of obtaining a masking effect to the film, a method of forming a large number of fine cavities inside the film, and the like can be mentioned. It is preferable to use the methods in combination. Further, if necessary, a copolymerization component may be introduced into the resin for the layer A, and as other components, polyalkylene glycol, an additive such as a melt viscosity reducing agent or a thickening agent may be added.

As a method for forming fine cavities inside the A layer, for example, a thermoplastic resin which is a main raw material of the film and a resin which is incompatible with the thermoplastic resin are melt-mixed and biaxially mixed. There is a method of stretching. When polyester is used as the thermoplastic resin which is the main raw material of the film, polystyrene resin, polyolefin resin, polyacrylic resin, polycarbonate resin, polysulfone resin, cellulose resin, etc. are used as the incompatible resin. Can be mentioned. In particular, polystyrene resins or polyolefin resins such as polymethylpentene and polypropylene are preferably used. The amount of the incompatible resin to be mixed with the polyester varies depending on the amount of target cavities, but is preferably 3% by weight to 39% by weight, particularly 8% by weight.
35% by weight is preferred. If it is less than 3% by weight, there is a limit to increase the amount of cavities, and if it is 40% by weight or more,
The heat resistance and strength of the polyester film, particularly the strength of the waist, are significantly impaired.

When inorganic or organic particles are added to the layer A in order to improve the hiding property of the film, the particles that can be added are silica, kaolinite, talc, calcium carbonate, zeolite, alumina, barium sulfate, Examples include carbon black, zinc oxide, titanium oxide, and organic white pigments. Among them, the average particle size is 0.2 to 0.4
Most preferred is μm titanium oxide.

The present invention is a composite film in which a film (B layer) containing inorganic particles is provided on one side or both sides of the A layer. The type of the thermoplastic resin that is the raw material of the B layer is not particularly limited, and examples thereof include polyester resin, polystyrene resin, polyolefin resin, polyacrylic resin, polycarbonate resin, polysulfone resin, and cellulose resin. Is mentioned. Among these, the B layer is preferably the same type of resin as the A layer from the viewpoint of the strength of the bonding force with the A layer and the characteristics of the obtained film. Further, a resin having a structural unit basically similar to the resin used for the layer A is most preferable. For example, when polyester mainly composed of ethylene terephthalate is used as the resin for the A layer, it is most preferable to use a resin mainly composed of ethylene terephthalate or ethylene isophthalate for the B layer. Further, specific particles are added to the B layer as described below, but if necessary, the B layer resin may be added to
Additives such as polyalkylene glycol and melt viscosity reducer or thickener may be added together.

The film containing the inorganic particles of the present invention (B
It is necessary that at least one kind of particles having spherical or dice-like or intermediate shape having jagged unevenness on the surface is added to the layer). Adding particles having the above morphology is the most important requirement of the present invention. As a result, the matte feeling or surface roughness of the surface is large,
Moreover, a film having excellent surface peel strength can be obtained. When particles having no unevenness on the surface are used, the surface peeling strength becomes poor even if the particles have a spherical shape, a dice shape, or an intermediate shape. On the other hand, even if the particles have irregularities on the surface, if the shape is not spherical, dice-shaped or an intermediate shape (for example, irregularly shaped porous fine particles), the surface is The peel strength becomes poor.

The thicknesses of the A layer and the B layer are not particularly limited and are arbitrary, but the thickness of the B layer is 3 times the thickness of the A layer.
It is preferable that the thickness of the layer B is not more than one-half and the thickness of the layer B is not less than 0.5 μm. When the thickness of the B layer exceeds one-third of the thickness of the A layer, the void content of the entire film decreases, and the flexibility of the film tends to be impaired. Further, when the thickness of the B layer is 0.5 μm or less, the surface peel strength becomes insufficient.

The particle diameter of the particles added to the layer B, which have a spherical or dice-like shape having jagged irregularities on the surface or an intermediate shape thereof, and the addition amount thereof are arbitrary, but the average particle diameter is 0.3 μm or more. It is preferable. If the average particle size is less than 0.3 μm, sufficient matte feeling cannot be obtained. On the other hand, although there is no upper limit of the average particle size, if the average particle size becomes too large, the matte property is rather deteriorated. Therefore, the average particle size is preferably 6 μm or less. Further, the total amount of the particles having the above-mentioned morphology is preferably 0.1% by weight or more, more preferably 1% by weight or more. When the amount of particles added is 0.1% by weight or less with respect to the layer B, sufficient matting properties cannot be obtained. On the other hand, the upper limit of the addition amount is not limited, but in order not to impair the surface strength of the composite film, it is preferably 50% by weight or less in total.

The composition of the particles to be added to the B layer, which have a spherical or dice-like shape having jagged irregularities on the surface or an intermediate shape thereof, is not particularly limited and is arbitrary. Examples thereof include silica, kaolinite, talc, calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, titanium oxide and the like.
Among these, it is preferable that at least one kind of particles having the above-mentioned morphology is composed of synthetic zeolite particles, secondary agglomerates of silica fine particles, secondary agglomerates of calcium carbonate fine particles, and secondary agglomerates of titanium oxide fine particles, In particular, synthetic zeolite particles are the most preferable. When synthetic zeolite particles are used, they may be heat-treated products or non-heat-treated products, but heat-treated products are preferably used.
When using a secondary aggregate of silica fine particles,
It is preferable to use silica fine particles having a primary particle diameter of 0 to 50 nm, which are spherically aggregated and then sintered under appropriate conditions. Similarly, when using calcium carbonate fine particles or secondary agglomerates of titanium oxide, it is preferable to use the agglomerates sintered under appropriate conditions. Also,
When adding these particles into the film, before adding the particles into the resin, some component (e.g. colorant,
It may be used after adsorbing to the particles a component having affinity with the light-proofing agent, fluorescent agent, antistatic agent or matrix resin, or conversely component having poor affinity). Further, particles other than the particles having the above-described morphology may be added to the B layer in order to improve the hiding property and the drawing property, if necessary.

Further, in the A layer and / or the B layer, it is possible to add a colorant, a light fastness agent, a fluorescent agent, an antistatic agent, etc. depending on the use.

In a preferred embodiment of the present invention, substantially no voids are developed at the interface of the incompatible resin at the joint between the A layer and the B layer, and the average void content of the entire composite film is 10 volumes. % Or more and 50% by volume or less is preferable. This is because the surface peel strength of the film can be further improved by using a film in which substantially no voids are present at the interface of the incompatible resin at the joint between the A layer and the B layer. The preferable void content is 10% by volume or more and 50% by volume or less, and more preferably 40% by volume or less with respect to the entire composite film. This is because when the porosity is less than 10% by volume, the flexibility of the entire composite film tends to be insufficient, and the writability and drawability tend to be poor. On the other hand, a void-containing film having a void content of 50% by volume or more is difficult to manufacture because it frequently breaks in the stretching process, and the obtained film also has insufficient surface peel strength and tensile strength, which is not preferable. .

The method for obtaining the opaque composite film of the present invention is arbitrary and is not particularly limited.
Examples of the method of combining the layers include a coextrusion method, a laminating method, a coating method, and the like. Among these, the co-extrusion method in which the resin for layer A and the resin for layer B are supplied to different extruders, then laminated in a molten state and extruded from the same T die is most preferable.

Further, substantially no void is developed at the interface of the incompatible resin at the joint between the A layer and the B layer, and a void is formed at the interface of the incompatible resin other than at the joint between the A layer and the B layer. In order to develop, in the unstretched composite sheet immediately after coextruding the A layer and the B layer, a state in which the incompatible resin in the joint portion of the A layer and the B layer is dispersed like needles in the extrusion direction is created. It is preferable. The tips of the incompatible resins dispersed in a needle shape have a very small radius of curvature, and as a result, they act as particles that are substantially extremely small, and it becomes difficult for voids to appear at the resin interface. Further, even if a cavity appears, it is only at the two tip portions of the needle, so that the volume ratio of the cavity to the added amount of the incompatible resin can be minimized. This makes it possible to increase the peel strength between the A layer and the B layer. In this case, it is preferable that the acicular dispersed state is generated only in the vicinity of the junction between the A layer and the B layer. This is for optimizing the void content in the entire A layer and ensuring the cushioning property of the film.

In order to obtain an unstretched composite sheet in which an incompatible resin is dispersed as described above, it can be obtained by appropriately selecting the melting / extruding conditions for the resin of the layer A. For example, by making the shear stress acting on the pipe wall of the melt line from the extruder to the extrusion die and the slit of the extrusion die higher than usual, it is possible to create a flat dispersed state of the incompatible resin only in the vicinity of the surface layer. In addition to these conditions,
Furthermore, by making the melt viscosity difference between the polyester and the incompatible resin near the joint smaller than the relative viscosity difference between the two in the center, the flatness of the incompatible resin near the joint can be further increased. It is possible to have a shape. Generally, a polyolefin-based resin or a polystyrene-based resin has a larger melt viscosity than a polyester, and also has a larger rate of decrease in viscosity due to temperature increase. Utilizing this phenomenon,
By controlling the resin temperature near the interface between the A and B layers to be lower than that at the central portion, the relative viscosity difference can be controlled as described above. Then, in order to control the resin temperature distribution in this way, for example, in the usual melt extrusion method, while the resin is controlled in the process of passing through the melt line from the extruder to the extrusion die and the extrusion die, On the contrary, the temperature reduction control may be performed.

Further, in the method of obtaining a composite film by co-extrusion, the resin temperature of the A layer and the B layer can be controlled independently, and the incompatible resin is dispersed like needles only in the vicinity of the joint between the A layer and the B layer. It is an effective means to make it happen. In particular,
The resin temperature of the B layer is preferably lower than the resin temperature of the A layer, and the temperature difference is more preferably in the range of 5 to 15 ° C.

The unstretched composite sheet thus obtained is further stretched between rolls having a speed difference (roll stretch), stretched by gripping with a clip and expanded (tenter stretch), or expanded by air pressure. At least one axis is oriented by stretching (inflation stretching) or the like. In this stretching / orienting step, exfoliation occurs at the interface between the polyester and the incompatible resin except in the joint between the A layer and the B layer, and many cavities occur.

The conditions for stretching and orienting the unstretched composite sheet are important points for obtaining a film containing voids having a strong elasticity. In the following, the most favored sequential 2
The stretching / orienting conditions will be described by taking an axial stretching method, particularly a method of stretching the unstretched composite sheet in the longitudinal direction and then in the width direction as an example. First, in the first-stage longitudinal stretching process, the peripheral speed is different.
It is stretched between two or more rolls. As a heating means at this time, a method using a heating roll or a non-contact heating method may be used, or they may be used in combination. However, in order to develop many voids at the interface of the incompatible resin, the stretching temperature is set to the second-order transition temperature Tg of the polyester.
It is stretched 3 to 5 times at + 50 ° C or less. Then, the uniaxially stretched film is introduced into a tenter, and stretched in the width direction at a temperature not higher than the melting point Tm of polyester of −10 ° C. to 2.5 to 5 times.

The biaxially stretched film thus obtained is subjected to heat treatment, if necessary. The heat treatment is preferably carried out in a tenter, and the melting point of the polyester is Tm-50.
It is preferably carried out in the range of ° C to Tm.

The opaque composite film of the present invention may have a coating layer on at least one surface thereof. By providing the coating layer, the wettability and adhesiveness of the ink and the coating agent, or the antistatic property can be improved. As the compound constituting the coating layer, a polyester resin is preferable, but in addition to this, a compound disclosed as a means for improving the adhesiveness of a normal polyester film such as a polyurethane resin, a polyester urethane resin and an acrylic resin. Etc. are applicable. As a method for providing the coating layer, a commonly used method such as a gravure coating method, a kiss coating method, a dip method, a spray coating method, a curtain coating method, an air knife coating method, a blade coating method or a reverse roll coating method can be applied.
As the step of applying, a method of applying the composite sheet before the orientation treatment in advance, a method of applying it on the film surface after uniaxial orientation and further orienting it in the perpendicular direction, a film surface after the orientation treatment Any method, such as a method of applying it to the.

The opaque composite film thus obtained is
Compared to conventionally proposed opaque films, it has excellent matte properties and strong surface strength.

[0028]

EXAMPLES Examples and comparative examples of the present invention will be described below. The measurement / evaluation methods used in the present invention are shown below.

1) Intrinsic viscosity of polyester Polyester is dissolved in a mixed solvent of phenol (6 parts by weight) and tetrachloroethane (4 parts by weight) and measured at 30 ° C. 2) Melt flow index of polystyrene resin Measured at 200 ° C. under a load of 5 kg in accordance with JIS-K7210. 3) Apparent specific gravity The film is accurately cut into a square of 5.00 cm × 5.00 cm, the thickness is measured at 50 points, and the average thickness is t μm.
And the weight thereof is measured up to 0.1 mg to be wg, which is calculated by the following formula. Apparent specific gravity (−) = w / 5 × 5 × t × 10000

4) Average Porosity of Film Calculated by the following formula. Cavity content (volume%) = 100 × (1-true specific volume / apparent specific volume) However, true specific volume = x1 / d1 + x2 / d2 + x3 / d3 + ... + xi / d
i + ... Apparent specific volume = 1 / apparent specific gravity of film In the above formula, xi represents the weight fraction of the i component, and di represents the true specific gravity of the i component. The values of true specific gravity used in the calculations in the examples are polyethylene terephthalate 1.40, general-purpose polystyrene 1.05, and anatase type titanium dioxide 3.9.
Is.

5) Average particle size of inorganic particles For particles having a spherical shape, a dice shape, or an intermediate shape, the cross section of the film was observed with a scanning electron microscope (S-510, manufactured by Hitachi, Ltd.) at 10000 times. , The average diameter of any 100 particles is used for evaluation. Particles having other shapes can be obtained by sufficiently dispersing powder in EG slurry by high-speed stirring to obtain a particle size distribution in the slurry, which is a light transmission type centrifugal sedimentation type particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation. The value of 50% integration in the distribution measured using is used.

6) Definition of junction between layer A and layer B and thickness of layer B After embedding the composite film in an epoxy resin and curing it,
Using a microtome, a cut surface parallel to the film longitudinal direction and perpendicular to the film surface direction is created. At this time, the direction of cutting with the microtome is a direction parallel to the longitudinal direction of the film. Then, after metallizing this cut surface, it was made 30 with a S-510 scanning electron microscope manufactured by Hitachi, Ltd.
Observe at a magnification of 00 times. The observation is performed from the surface of the B layer toward the inner layer of the composite film, and the portion where the dispersion of the incompatible resin is first confirmed is defined as the joint portion of the A layer and the B layer. Then, the thickness of the B layer is obtained from the distance from the surface of the B layer to the joint portion.

7) Size of Cavity and Presence / Absence of Cavity at Junction of A Layer and B Layer Cavity observed at both ends of the interface between the incompatible resin and the matrix resin existing in the junction defined in 6) ( (Having a thickness of 0.5 μm or more in the film thickness direction) is measured in units of 1 μm, and the average value is calculated. The same measurement is performed on the interface between any 50 incompatible resins and the matrix resin, and the average value is calculated. It should be noted that measuring the cavities with an accuracy less than this is meaningless in consideration of the deformation of the film at the time of cutting. Also, even if there are cavities that are not detected by this method, they are very fine cavities and have little effect on the surface peel strength of the composite film. Therefore, the case where no cavity is detected by this method is defined as substantially no cavity.

8) Surface glossiness Nippon Denshoku Co., Ltd. gloss meter (VGS-1001D)
P) was used to measure 60 ° gloss, and the glossiness was evaluated. 70-100 ... × 45-69 ・ ・ ・ △ 20-44 ・ ・ ・ ○ 10-19 ・ ・ ・ ◎

9) Surface Peel Strength Using cellophane tape (18 mm width, made by Nichiban), the surface peel strength is evaluated by a cellophane tape peel test. The peeling angle is in the direction of about 150 degrees while keeping the void-containing film flat. Differentiate as follows based on the area of the void-containing film to be peeled off. Class 5 ... Peeled off entirely Class 4 ... Almost peeled off Class 3 ... Around half peeled off Class 2 ... Almost peeled off Class 1 ... No peeled off at all

Example 1 As a raw material, 80% by weight of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62 was added to a melt flow index of 2.0.
A mixture of 15% by weight of general-purpose polystyrene for 15 minutes and 5% by weight of anatase-type titanium dioxide having an average particle size of 0.3 μm (electron microscope method) was used as the raw material of the A layer, and the intrinsic viscosity of 0. A mixture of 80% by weight of polyethylene terephthalate resin No. 62 and 20% by weight of dice-shaped synthetic zeolite particles (AMT-08 manufactured by Mizusawa Chemical Co., Ltd.) having an average particle size of 0.6 μm and having unevenness on the surface is B Used as the raw material of the layer. 2 of these ingredients
The mixture was supplied to an axial screw extruder, and the layer A and the layer B were laminated and extruded using a co-extrusion die. Then, the extruded product was electrostatically adhered and solidified on a cooling rotating roll to obtain an unstretched composite sheet having a layer thickness of B / A = 50/450 μm. At this time, the resin temperature of the most advanced part of the screw of the extruder for layer A was set to 290 ° C. After that, the melt line temperature is gradually decreased, and finally the temperature of the T-die is increased to 2
It was set at 80 ° C. On the other hand, the resin temperature at the most distal portion of the screw of the B layer extruder was 280 ° C. After that, the raw material was supplied to the melt line at the same temperature and supplied to the co-extrusion die. At this time, the slit interval of the T-die is 1.0
In mm, the average flow rate of the polymer mixture melt in that part was 8.8 m / sec. When the cross section of the thus-obtained unstretched composite sheet was observed, polystyrene was needle-like dispersed in the vicinity of the interface between layers A and B. Then, this unstretched composite sheet was longitudinally stretched 3.5 times at 83 ° C. by a roll stretching machine, and subsequently horizontally stretched 3.5 times at 140 ° C. by a tenter, and then heat-treated at 235 ° C. while being relaxed by 4% to be opaque. A composite film was obtained. Thickness is B / A = 5μm
/ 45 μm. The properties of the resulting opaque composite film are shown in Table 1.

Comparative Example 1 Polyethylene terephthalate resin 80 as raw material for layer B
An opaque composite film was obtained in the same manner as in Example 1 except that a mixture of 20% by weight of calcium carbonate particles having an average particle size of 0.6 μm (electron microscope method) was used. The characteristics of the obtained film are shown in Table 1.

Example 2 Polyethylene terephthalate resin 98 as a raw material for layer B
Spherical synthetic zeolite particles having a weight percentage of 1.5 μm and an average particle diameter of 1.5 μm and having jagged irregularities on the surface (Mizusawa Chemical Co., Ltd.)
JC-20) manufactured by JC-20) was used as a raw material for the layer B, and an opaque composite film was obtained in the same manner as in Example 1 except that the thickness of each layer was B / A = 3 μm / 35 μm. It was The characteristics of the obtained film are shown in Table 1.

Comparative Example 2 Polyethylene terephthalate resin 95 as a raw material for the B layer
An opaque composite film was obtained in the same manner as in Example 2 except that a mixture of 5% by weight of amorphous porous silica having an average particle diameter of 2.5 μm (centrifugal sedimentation method) was used. The characteristics of the obtained film are shown in Table 1.

Example 3 Polyethylene terephthalate resin 95 as a raw material for layer B
A mixture of 5% by weight and 5% by weight of dice-shaped synthetic zeolite particles (AMT-50 manufactured by Mizusawa Chemical Co., Ltd.) having an average particle diameter of 4.5 μm and unevenness on the surface is B.
An opaque composite film was obtained in the same manner as in Example 1 except that it was used as the raw material for the layer. The characteristics of the obtained film are shown in Table 1.

Comparative Example 3 Polyethylene terephthalate resin 95 as a raw material for the B layer
An opaque composite film was obtained in exactly the same manner as in Example 1, except that a mixture of 5% by weight and 5% by weight of spherical silica having an average particle diameter of 3.0 μm was used as the raw material for the layer B. The characteristics of the obtained film are shown in Table 1.

Example 4 Polyethylene terephthalate resin 8 having an intrinsic viscosity of 0.62
A mixture of 5% by weight and 15% by weight of general-purpose polystyrene having a melt flow index of 2.0 g / 10 min was used as a raw material for the A layer, and as a raw material for the B layer, 95% by weight of polyethylene terephthalate resin and anatase-type titanium dioxide fine particles were used. Spherical particles that are secondary agglomerates and have an average particle diameter of 5 μm and have jagged irregularities on the surface (S manufactured by Catalyst Kasei Kogyo Co., Ltd.)
PHERITAN, AA-1512-I) 5% by weight
An opaque composite film was obtained in the same manner as in Example 2 except that a mixture of the above was used. The characteristics of the obtained film are shown in Table 1.

Example 5 Polyethylene terephthalate resin 95 as a raw material for the B layer
Spherical particles having a mean particle size of 5 μm and jagged irregularities on the surface (SPHERICA, P-1000 manufactured by Catalysts & Chemicals Industry Co., Ltd.)
An opaque composite film was prepared in the same manner as in Example 1 except that a mixture of 5% by weight was used, the layer constitution was three layers, and the thickness of each layer was B / A / B = 3/44/3 μm. Got The characteristics of the obtained film are shown in Table 1.

Example 6 87% by weight of polyethylene terephthalate resin having an intrinsic viscosity of 0.62 as a raw material for the A layer, 8% by weight of crystalline polypropylene having a melt flow index of 5.5 g / 10 min, and an average particle diameter of 0.3 μm (electricity). 5% by weight of anatase type titanium dioxide of the (microscopic method) was used, and 95% by weight of polyethylene terephthalate resin as a raw material for layer B and a secondary aggregate of calcium carbonate fine particles having an average particle diameter of 3 μm and having a jagged surface. An opaque composite film was obtained in exactly the same manner as in Example 1, except that 5% by weight of dice particles having irregularities (CUBE-30 manufactured by Maruo Calcium Co., Ltd.) were mixed. The characteristics of the obtained film are shown in Table 1.

[0045]

[Table 1]

[0046]

EFFECTS OF THE INVENTION The opaque composite film of the present invention has an excellent surface matte feeling and sufficient surface peeling without impairing the flexibility of the opaque composite film obtained by using a conventional polystyrene or polyolefin as a cavity-developing agent. And has strength.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshitake Suzuki 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd.

Claims (8)

[Claims] 1. A composite film in which a film (B layer) containing inorganic particles is laminated on one or both sides of an opaque film (A layer) having a light transmittance of 50% or less. An opaque composite film, to which spherical or dice-shaped particles having unevenness on the surface or particles having an intermediate shape thereof are added. 2. The layer A and / or the layer B is a film containing polyester as a main component.
The opaque composite film according to 1. 3. The opaque composite film according to claim 1, wherein the layer A is a void-containing film having voids of 10% by volume or more. 4. A void is not substantially developed at the interface of the incompatible resin at the joint between the A layer and the B layer, and the average void content of the entire film is 10% by volume or more and 50% by volume or less. The opaque composite film according to claim 3, wherein: 5. The opaque composite film according to any one of claims 1 to 4, wherein at least one kind of particles having spherical or dice-like or uneven shape having jagged unevenness on the surface is made of synthetic zeolite. 6. The method according to claim 1, wherein at least one kind of particles having a spherical or dice-like shape having jagged irregularities on the surface or an intermediate shape thereof is composed of a secondary aggregate of silica fine particles. Opaque composite film. 7. The method according to claim 1, wherein at least one kind of particles having a spherical or dice shape having jagged irregularities on the surface or an intermediate shape thereof is composed of a secondary aggregate of calcium carbonate fine particles. Opaque composite film. 8. The method according to claim 1, wherein at least one kind of particles having a spherical or dice-like shape having jagged irregularities on the surface or an intermediate shape thereof is composed of a secondary aggregate of titanium oxide fine particles. Opaque composite film.