JP3316963B2 - Opaque composite film - Google Patents

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 having excellent matting properties and high surface strength. More specifically, labels, stickers, posters, cards, recording paper, packaging materials, video printer receiving paper, barcode labels, barcode printer receiving paper, thermal transfer receiving paper,
Thermal recording paper, sublimation transfer receiving paper, inkjet receiving paper, offset printing paper, form 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 card, tracing paper, slip, delivery slip, pressure-sensitive recording paper,
The present invention relates to an opaque composite film having a matting property suitable for base materials such as copying paper, clinical examination paper, a parabolic antenna reflector, and a display reflector.

[0002]

2. Description of the Related Art Opaque films made of synthetic resin as a main raw material have water resistance, dimensional stability of moisture absorption, gloss and sharpness of printing,
Due to its excellent mechanical strength, it is being developed for use as a synthetic paper alternative to paper.

As the main raw material of the opaque film, polyethylene, polypropylene, polyester and the like are used. Among them, polyester typified by polyethylene terephthalate is excellent in that it has high heat resistance and is strong. It can be used for a wide range of applications.

As a method for obtaining an opaque film using polyester as a main raw material, a method has been proposed in which inorganic particles having concealing properties are added to the film or fine voids are contained in the film.

However, films obtained by these methods have a high gloss on the surface of the film, have a poor appearance as a substitute for paper, and need to be roughened in order to impart a matting property to the film. there were. For this purpose, a method has been proposed in which particles having a large particle size such as calcium carbonate and 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 becomes poor and the mechanical strength of the film is greatly reduced. Also, the latter method has a problem that the mechanical strength of the surface layer is reduced, and when the surface layer is subjected to adhesive processing and used for an application such as a label, the surface layer is peeled off when peeled off. there were.

[0006]

SUMMARY OF THE INVENTION The present invention has the drawbacks of the prior art, namely, the problem that it is extremely difficult to obtain an opaque film having excellent mechanical strength, high quality matte feeling and sufficient surface peel strength. It is to be solved.

[0007]

According to the present invention, there is provided a composite film comprising a film (layer B) containing inorganic particles laminated on one or both sides of an opaque film (layer A) having a light transmittance of 50% or less. The opaque composite film is characterized in that the layer B has spherical or dice-shaped particles having jagged irregularities on its surface or particles having an intermediate shape added thereto.

[0008] Opaque film (layer A) in the present invention
Any composition may be used as long as it is mainly made of a thermoplastic resin, but it 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. Polyester produced by polycondensation. These polyesters can be directly reacted with an aromatic dicarboxylic acid and a glycol, or subjected to a transesterification reaction between an alkyl ester of an aromatic dicarboxylic acid and a glycol, followed by polycondensation, or a diglycol of an aromatic dicarboxylic acid. It can be produced by a method such as polycondensation of an ester.
Representative examples of such polyesters include polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. This polyester may be a homopolymer or a copolymer of the third component. In any case, in the present invention, it is preferable to use a polyester having an ethylene terephthalate unit or an ethylene-2,6-naphthalate unit of 70 mol% or more, preferably 80 mol% or more.

The opaque film (layer A) of the present invention may be of any type as long as it has a light transmittance of 50% or less. In order to reduce the light transmittance to 50% or less, a method of adding inorganic or organic particles capable of providing a hiding effect to the film or a method of forming a large number of fine cavities inside the film may be used. It is preferable to use a combination of the methods. If necessary, a copolymerization component may be introduced into the resin of the layer A, and as other components, additives such as polyalkylene glycol, a melt viscosity reducing agent or a thickener may be added.

As a method for forming fine cavities inside the layer A, for example, a thermoplastic resin as a main raw material of a film and a resin incompatible with the thermoplastic resin are melt-mixed to form a biaxial resin. There is a method of stretching. When using polyester as the thermoplastic resin as the main material of the film, as the incompatible resin, polystyrene resin, polyolefin resin, polyacrylic resin, polycarbonate resin, polysulfone resin, cellulose resin, etc. No. In particular, polystyrene resins or polyolefin resins such as polymethylpentene and polypropylene are preferably used. The amount of the immiscible resin to be mixed with the polyester varies depending on the desired amount of cavities, but is preferably 3% by weight to 39% by weight, particularly preferably 8% by weight.
35% by weight is preferred. If the amount is less than 3% by weight, there is a limit in increasing the amount of cavities.
The heat resistance and strength of the polyester film, especially the strength of the waist, are significantly impaired.

When inorganic or organic particles are added to the layer A in order to improve the concealing properties of the film, silica, kaolinite, talc, calcium carbonate, zeolite, alumina, barium sulfate, Examples thereof include carbon black, zinc oxide, titanium oxide, and organic white pigment. Among them, the average particle size is 0.2 to 0.4.
μm titanium oxide is most preferred.

The present invention is a composite film, in which a film containing inorganic particles (layer B) is provided on one or both sides of layer A. The type of the thermoplastic resin used as the raw material of the layer B is not particularly limited, and examples thereof include a polyester resin, a polystyrene resin, a polyolefin resin, a polyacryl resin, a polycarbonate resin, a polysulfone resin, and a cellulose resin. Is mentioned. Among these, it is preferable that the layer B is also the same type of resin as the layer A from the viewpoint of the strength of the bonding force with the layer A 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 a polyester mainly composed of ethylene terephthalate is used as the resin of the layer A, it is most preferable to use a resin mainly composed of ethylene terephthalate or ethylene isophthalate for the layer B. Also, specific particles are added to the B layer as described below, but if necessary,
An additive such as a polyalkylene glycol, a melt viscosity reducing agent or a thickener may be added together.

The film (B) containing the inorganic particles of the present invention
It is necessary that at least one kind of spherical or dice-shaped particles having a jagged unevenness on the surface or particles having an intermediate shape thereof is added to the layer). The addition of particles having the above morphology is the most important requirement of the present invention. Due to this, the matte feeling or surface roughness of the surface is large,
In addition, a film having excellent surface peel strength can be obtained. When particles having no jagged irregularities on the surface are used, even if they are spherical or dice-like or particles having an intermediate shape between them, the surface peel strength becomes poor. On the other hand, even in the case of particles having irregularities on the surface, if the shape is not spherical or dice-like or an intermediate shape thereof (for example, irregularly shaped porous fine particles), it is difficult to obtain a sufficient matte feeling on the surface. 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 is not more than 1 / and the thickness of the layer B is not less than 0.5 μm. If the thickness of the layer B exceeds one-third of the thickness of the layer A, the void content of the whole film tends to decrease, and the flexibility of the film tends to be impaired. When the thickness of the layer B is 0.5 μm or less, the surface peel strength becomes insufficient.

The particle size and the amount of the spherical or dice-shaped or intermediate-shaped particles having a jagged surface on the surface added to the layer B are arbitrary, but the average particle size is 0.3 μm or more. Is preferred. If the average particle size is less than 0.3 μm, a sufficient matte feeling cannot be obtained. On the other hand, there is no upper limit for the average particle diameter, but if the average particle diameter is too large, the matting property is rather deteriorated. Therefore, the average particle diameter is preferably 6 μm or less. Further, the total amount of the particles having the above-mentioned form is preferably 0.1% by weight or more, more preferably 1% by weight or more. If the amount of the particles added is 0.1% by weight or less based on the layer B, sufficient matting properties cannot be obtained. On the other hand, the upper limit of the amount of addition is not limited, but is preferably 50% by weight or less in total so as not to impair the surface strength of the composite film.

The composition of the particles to be added to the layer B and having the shape of a sphere or a dice having a jagged unevenness on the surface or a particle having an intermediate shape thereof is not particularly limited and is arbitrary. For example, silica, kaolinite, talc, calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, titanium oxide and the like are exemplified.
Among them, it is particularly preferable that at least one of the particles having the above-mentioned form is composed of a synthetic zeolite particle, a secondary aggregate of silica fine particles, a secondary aggregate of calcium carbonate fine particles, and a secondary aggregate of titanium oxide fine particles, Particularly, synthetic zeolite particles are most preferable. When using synthetic zeolite particles, a heat-treated product or an unheated product may be used, but it is preferable to use a heat-treated product.
When a secondary aggregate of silica fine particles is used, 1
It is preferable to use silica fine particles having a primary particle diameter of 0 to 50 nm which are aggregated in a spherical shape and then sintered under appropriate conditions. Similarly, when a secondary aggregate of calcium carbonate fine particles or titanium oxide is used, it is also preferable to use an aggregate obtained by sintering the aggregate under appropriate conditions. Also,
When these particles are added to the film, some component (for example, a coloring agent,
It may be used after adsorbing a light-fast agent, a fluorescent agent, an antistatic agent, a component having an affinity for the matrix resin, or a component having a low affinity on the contrary) to the particles. In addition, particles other than the particles having the above-described form may be added to the B layer, if necessary, in order to improve concealing properties and drawing properties.

In the A layer and / or the B layer, a coloring agent, a light-fast agent, a fluorescent agent, an antistatic agent and the like can be added according to the application.

According to a preferred embodiment of the present invention, substantially no voids are formed at the interface of the incompatible resin at the junction between the layer A and the layer B, and the average void content of the entire composite film is 10 vol. % Or more and 50% by volume or less. This is because the surface peel strength of the film can be further improved by using a film having substantially no voids at the interface of the incompatible resin at the joint between the layer A and the layer B. The preferred void content is 10% by volume or more and 50% by volume or less, more preferably 40% by volume or less, based on the entire composite film. This is because, when the porosity is less than 10% by volume, the flexibility of the entire composite film becomes insufficient, and writing and drawing tend to be poor. Conversely, a void-containing film having a void ratio of 50% by volume or more is not preferable because it often causes breakage in the stretching step itself, and the resulting film also has insufficient surface peel strength and tensile strength. .

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

Further, substantially no void is formed at the interface of the incompatible resin at the joint between the layer A and the layer B, and a cavity is formed at the interface of the incompatible resin other than the joint between the layer A and the layer B. In order to make this manifest, in the unstretched composite sheet immediately after the co-extrusion of the A layer and the B layer, a state is created in which the incompatible resin at the joint between the A layer and the B layer is dispersed in a needle shape in the extrusion direction. Is preferred. The tips of the incompatible resin dispersed in the form of needles have an extremely small radius of curvature, and as a result, act substantially as extremely small particles, making it difficult for voids to appear at the resin interface. Furthermore, even if a cavity appears, it is only at both ends of the needle, so that the volume ratio of the cavity to the amount of the incompatible resin added can be minimized. This makes it possible to further increase the peel strength between the layer A and the layer B. In this case, it is preferable that the needle-shaped dispersion state is generated only in the vicinity of the joint between the layer A and the layer B. This is for the purpose of optimizing the void content of the entire layer A and securing the cushioning properties of the film.

In order to obtain an unstretched composite sheet in which the incompatible resin is dispersed as described above, the unstretched composite sheet can be obtained by appropriately selecting the conditions for melting and extruding the resin of the layer A. For example, by making the shear stress acting on the tube wall of the melt line from the extruder to the extrusion die or the slit of the extrusion die higher than usual, a flat incompatible resin dispersion state can be created only near the surface layer. In addition to these conditions,
Further, by making the difference in melt viscosity between the polyester and the incompatible resin near the joint smaller than the difference in the relative viscosity between the two in the center, the flatness of the incompatible resin near the joint is increased to increase the needle. It is possible to form. In general, polyolefin-based resins and polystyrene-based resins have a higher melt viscosity than polyesters, and have a greater rate of viscosity decrease due to temperature rise. Using this phenomenon,
By controlling the resin temperature near the interface between the A and B layers to be lower than that at the center, the relative viscosity difference can be controlled as described above. And in order to control the resin temperature distribution in this way, for example, in a normal melt extrusion method, while controlling the temperature rise in the process where the resin passes through a melt line or an extrusion die from an extruder to an extrusion die, Conversely, temperature reduction control may be performed.

In the method of obtaining a composite film by co-extrusion, the resin temperature of the layer A and the resin of the layer B are independently controlled, and the incompatible resin is dispersed in a needle shape only in the vicinity of the junction between the layer A and the layer B. It is an effective means to make it work. In particular,
The resin temperature of the layer B is preferably lower than the resin temperature of the layer A, 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 different speeds (roll stretching), stretched by gripping and expanding with clips (tenter stretching), or expanded by air pressure. At least uniaxial orientation treatment is performed by stretching (inflation stretching) or the like. In the stretching / orienting step, exfoliation occurs at the interface between the polyester and the incompatible resin except for the joint between the layer A and the layer B, and a large number of cavities are generated.

The conditions for stretching and orienting the unstretched composite sheet are important points for obtaining a stiff void-containing film. In the following, the most preferred sequential 2
The stretching / orienting conditions will be described by taking as an example an axial stretching method, particularly a method of stretching an unstretched composite sheet in the longitudinal direction and then in the width direction. First, in the first-stage longitudinal stretching step, the peripheral speeds are different.
The film is stretched between two or more rolls. As a heating means at this time, a method using a heating roll, a method using a non-contact heating method may be used, or both may be used. However, in order to develop a large number of cavities at the interface of the incompatible resin, the stretching temperature is set to the secondary transition temperature Tg of the polyester.
The film is stretched 3 to 5 times at + 50 ° C. or lower. Next, the uniaxially stretched film is introduced into a tenter, and stretched 2.5 to 5 times in the width direction at a temperature equal to or lower than the melting point Tm-10 ° C of the polyester.

The thus-obtained biaxially stretched film is optionally subjected to a heat treatment. The heat treatment is preferably performed in a tenter, and the melting point of the polyester is Tm-50.
It is preferable to carry 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 of the surfaces. By providing the coating layer, it is possible to improve the wettability and adhesiveness of the ink and the coating agent, and the like, or the antistatic property. As the compound constituting the coating layer, a polyester resin is preferable, and in addition, 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, and a reverse roll coating method can be applied.
As a step of applying, a method of applying in advance to the composite sheet before performing the orientation treatment, a method of applying the film to the film surface after orienting in the uniaxial direction, and further orienting the film surface in the perpendicular direction, a surface of the film after the orientation treatment is completed Any method such as a method of applying to the surface is possible.

The opaque composite film thus obtained is
Compared to conventionally proposed opaque films, they have excellent matting properties and strong surface strength.

[0028]

Next, examples of the present invention and comparative examples will be described. The measurement / evaluation method used in the present invention will be described below.

1) Intrinsic viscosity of polyester The 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 according to JIS-K7210. 3) The apparent density film was accurately cut out into a square of 5.00 cm × 5.00 cm, the thickness was measured at 50 points, and the average thickness was t μm.
The weight is measured up to 0.1 mg, set as wg, and calculated by the following formula. Apparent density (g / cm ³ ) = w / ( 5 × 5 × t ) × 10000

4) Average porosity of film Calculated by the following equation. Cavity content (volume%) = 100 × (1-true specific volume / apparent specific volume) where true specific volume = x1 / d1 + x2 / d2 + x3 / d3 + ... + xi / di + ... apparent specific volume = 1 / film the xi of the apparent density above formula weight fraction of i component, di represents the true density of the i component (g / ^cm 3). The values of the true density (g / cm ³ ) used in the calculations in the examples are polyethylene terephthalate 1.40, general-purpose polystyrene 1.05, and anatase type titanium dioxide 3.9.

5) Average Particle Size of Inorganic Particles For particles having a spherical shape, a dice shape, or an intermediate shape thereof, the cross section of the film was observed at a magnification of 10,000 using a scanning electron microscope (S-510, manufactured by Hitachi, Ltd.). The evaluation is made using the average diameter of arbitrary 100 particles. Particles having other shapes are obtained by sufficiently dispersing the powder in an EG slurry by high-speed stirring, and the particle size distribution in the obtained slurry is measured by using a light transmission centrifugal sedimentation type particle size analyzer SA-CP3 manufactured by Shimadzu Corporation. The value of 50% of the integrated value in the distribution measured using is used.

6) Definition of junction between layer A and layer B and thickness of layer B After the composite film is embedded in epoxy resin and cured,
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 the cut surface, a 30-micron scanning electron microscope manufactured by Hitachi, Ltd. was used.
Observe at a magnification of 00 times. The observation is performed from the surface of the layer B toward the inner layer of the composite film, and a portion where the dispersion of the incompatible resin is first confirmed is defined as a joint between the layer A and the layer B. Then, the thickness of the layer B is determined from the distance from the surface of the layer B to the joint.

7) Size of cavity and presence / absence of cavity at the joint between layer A and layer B Cavities observed at both ends of the interface between the immiscible resin and the matrix resin existing at the joint defined in 6) The length of the film having a thickness of 0.5 μm or more in the film thickness direction is measured in 1 μm units, and the average value is taken. The same measurement is performed for any 50 interfaces between the incompatible resin and the matrix resin, and the average value is obtained. It is meaningless to measure the cavity with an accuracy lower than this, considering the deformation of the film at the time of cutting. Also, if any cavities 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)
Using P), a gloss of 60 ° was measured, and the gloss was evaluated. 70 to 100 ··· 45 to 69 ··· 20 to 44 ··· 10 to 19 ···

9) Surface Peeling Strength Using a cellophane tape (18 mm width, made by Nichiban), the surface peeling strength is evaluated by a cellophane tape peeling test. The peel angle is performed in the direction of about 150 degrees while the cavity-containing film is kept flat. The area is differentiated from the area of the void-containing film to be peeled as follows. Class 5: The whole has peeled off Class 4: Almost peeled off Class 3 ... About half the peeled off Class 2 ... Almost no peeling Class 1 ... No peeling 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 polystyrene for general use at 15 g / 10 min and 5% by weight of anatase type titanium dioxide having an average particle size of 0.3 μm (electron microscopic method) was used as a raw material for the layer A, and a material having an intrinsic viscosity of 0.1 was used as a raw material for the layer B. A mixture of 80% by weight of polyethylene terephthalate resin of No. 62 and 20% by weight of synthetic zeolite particles (AMT-08 manufactured by Mizusawa Chemical Co., Ltd.) having an average particle diameter of 0.6 μm and having irregularities on the surface has a weight of B. The raw material for the layer. These raw materials are each separated 2
The mixture was supplied to an axial screw extruder, and layer A and layer B were laminated and extruded using a co-extrusion die. Next, the extruded product was electrostatically adhered to and solidified on a cooling rotating roll to obtain an unstretched composite sheet having each layer thickness of B / A = 50/450 μm. At this time, the resin temperature at the tip of the screw of the extruder for layer A was set to 290 ° C. Thereafter, the temperature of the melt line was gradually lowered, and finally the temperature of the T-die was reduced to 2 °.
The temperature was set at 80 ° C. On the other hand, the resin temperature at the tip of the screw of the extruder for layer B was 280 ° C. Thereafter, the raw materials were 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 melt of the polymer mixture in that part was 8.8 m / sec. Observation of the cross section of the unstretched composite sheet thus obtained showed that polystyrene was dispersed in a needle shape near the interface between the A and B layers. Next, the unstretched composite sheet is longitudinally stretched 3.5 times at 83 ° C. with a roll stretching machine, and subsequently transversely stretched 3.5 times at 140 ° C. with a tenter. A composite film was obtained. The thickness is B / A = 5 μm
/ 45 μm. Table 1 shows the properties of the obtained opaque composite film.

COMPARATIVE EXAMPLE 1 Polyethylene terephthalate resin 80 was used as a raw material for layer B.
An opaque composite film was obtained in exactly the same manner as in Example 1, except that a mixture of 20% by weight of calcium carbonate particles having an average particle diameter of 0.6 μm (electron microscopic method) was used. Table 1 shows the properties of the obtained film.

Example 2 Polyethylene terephthalate resin 98 was used as a raw material for layer B.
Spherical synthetic zeolite particles having a weight% and an average particle diameter of 1.5 μm and having jagged irregularities on the surface (Mizusawa Chemical Industries, Ltd.
An opaque composite film was obtained in exactly the same manner as in Example 1 except that a mixture of 2% by weight of JC-20) was used as a raw material for the B layer, and the thickness of each layer was B / A = 3 μm / 35 μm. Was. Table 1 shows the properties of the obtained film.

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

Example 3 A polyethylene terephthalate resin 95 was used as a raw material for the layer B.
A mixture of 5% by weight and 5% by weight of synthetic zeolite particles (AMT-50 manufactured by Mizusawa Chemical Co., Ltd.) in the form of dice having an average particle diameter of 4.5 μm and having jagged irregularities on the surface was mixed with B.
An opaque composite film was obtained in exactly the same manner as in Example 1, except that the opaque composite film was used as a raw material for the layer. Table 1 shows the properties of the obtained film.

COMPARATIVE EXAMPLE 3 A polyethylene terephthalate resin 95 was used as a raw material for the layer B.
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 a raw material for the layer B. Table 1 shows the properties of the obtained film.

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

Example 5 Polyethylene terephthalate resin 95 was used as a raw material for layer B.
Spherical particles having a mean particle size of 5 [mu] m and having a jagged surface on the surface (SPHERICA, P-1000, manufactured by Catalyst Chemical Industry Co., Ltd.)
An opaque composite film was prepared in exactly the same manner as in Example 1 except that a mixture of 5% by weight was used, the layer configuration was made into three layers, and the thickness of each layer was set to B / A / B = 3/44/3 μm. I got Table 1 shows the properties of the obtained film.

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

[0045]

[Table 1]

[0046]

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

Continuation of the front page (72) Inventor Toshitake Suzuki 2-1-1 Katata, Otsu City, Shiga Prefecture Toyo Spinning Co., Ltd. General Research Laboratory (56) References JP-A-63-265639 (JP, A) JP-A-5-205 329970 (JP, A) JP-A-5-329969 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. One or both sides of an opaque film (layer A) having a light transmittance of 50% or less, at least one inorganic particle having a spherical shape, a dice shape, or an intermediate shape thereof.
A composite film formed by laminating a seed-containing film (layer B), wherein the inorganic particles are synthetic zeolite, a secondary aggregate of silica fine particles, a secondary aggregate of calcium carbonate fine particles, or a secondary aggregate of titanium oxide fine particles. An opaque composite film, which is an aggregate. 2. 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. 3. The layer A is mainly composed of a first thermoplastic resin and a resin incompatible with the first thermoplastic resin, and the layer B is the same as or different from the first thermoplastic resin. 3. The opaque composite film according to claim 2, comprising mainly a second thermoplastic resin. 4. A cavity substantially does not appear at an interface between a first thermoplastic resin present at a joint between the A layer and the B layer and a resin incompatible with the first thermoplastic resin. The opaque composite film according to claim 3, wherein the average void content of the entire film is 10% by volume or more and 50% by volume or less. 5. The opaque composite film according to claim 3, wherein both the first thermoplastic resin and the second thermoplastic resin are polyester.