JP3156058B2 - Field-selective film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer resin film having visual field selectivity and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, for example, a so-called field-selective glass sheet which is transparent when viewed from the front and becomes opaque when viewed from an oblique direction, is often used in which an organic polymer film is bonded in two phases. In this conventional sheet glass, the organic polymer film has a non-uniform phase separation structure inside, and the visual field selectivity is expressed by the difference in refractive index between these two phases. However, in this case, a complicated process of bonding the organic polymer film is required, so that the productivity is inferior, and the cost is high because the organic polymer film itself is expensive.

Therefore, a light control plate and a method for manufacturing the same having a uniform film quality for selectively scattering only specific incident light has been proposed in Japanese Patent Application Laid-Open No. Sho 64-77001. The light control plate described in this publication can selectively scatter only incident light at a specific angle without bonding sheets made of a resin composition in two phases, thereby providing a certain degree of field selectivity. Is obtained.

[0004]

However, in the conventional light control plate described in JP-A-64-77001, the resin composition contains at least one resin composition in a molecule having a difference in refractive index. It is expensive because it is made of a compound having a polymerizable carbon-carbon double bond, and it is necessary to cure the resin composition by light after applying it on a substrate, which makes the production process complicated and cost-effective. Was also disadvantageous.

Accordingly, the present invention was devised. The first object of the present invention is that a single film itself has a field-of-view selectivity. It is an object of the present invention to provide a field-selective film at a lower cost than an object coated on a substrate. A second object of the present invention is to provide a visual field selective film having a function obtained from an additive. Further, a third object of the present invention is as follows.
An object of the present invention is to provide a method for easily producing a field-selective film in which the tensile strength hardly decreases.

[0006]

Means taken by the present invention to achieve the above object will be described below with reference to the reference numerals used in the drawings corresponding to the embodiments. That is, as shown in FIGS. 1 and 2, the configuration of the visual field selectable film according to claim 1 is that “a transparent polymer resin film 10 has stripes substantially parallel to the molecular orientation direction of the polymer resin film 10. The field of view-selective film 100 is characterized by having a craze-shaped 20 region.

Next, the structure of the field-selective film according to claim 2 is that the additive layer is provided in the region of the craze 20.
"0" as the content. The additive layer referred to here is a coloring agent,
A layer containing at least one of additives such as a stabilizer, a flame retardant, a plasticizer, and an ultraviolet absorber, and thereby has a function corresponding to the type of these additives.

Next, the construction of the method for producing a visual field selective film according to claim 3 is as shown in FIG. 1, FIG. 2 or FIG.
“The transparent polymer resin film 10 is bent substantially parallel to the molecular orientation direction of the polymer resin film 10 to form a local bent portion 11, and then the polymer resin film 10 is bent at the bent portion. For the bending line
And forming a continuous stripe-shaped craze 20 region substantially parallel to the molecular orientation direction of the polymer resin film 10 by pulling in a direction perpendicular to the polymer resin film 10 ". Is what you do.

The structure of the method for producing a visual field selective film according to claim 4 is as shown in FIG. 1, FIG. 2, FIG. 6 or FIG. The polymer resin film 10 is bent substantially in parallel with the molecular orientation direction by pressing the support body 40 having the tip 41 with an acute angle on the ten surfaces, thereby forming a local bent portion 11 thereon. in the bent portion while contacting the film 10 at the distal end of the support 40
A method for producing a field-selective film, comprising forming a continuous striped craze 20 region substantially parallel to the molecular orientation direction of the polymer resin film by pulling in a direction perpendicular to the bending line. ".

The term “craze 20 region” as used herein includes both surface craze appearing on the surface of the polymer resin film 10 and internal craze occurring therein.
It refers to a region having a fine crack-like pattern. The craze 20 is composed of a molecular bundle (fibril) and a void, and has a structure similar to a sponge as a whole.

[0011]

According to the above means, as shown in FIGS. 1 and 2,
In the visual field selectable film 100 according to claim 1,
Since the transparent polymer resin film 10 is provided with the stripe-shaped craze 20 regions substantially parallel to the molecular orientation direction, as shown in FIG. Light incident parallel is transmitted, and light obliquely incident is reflected and scattered as shown in FIG. On the other hand, when the distance between the crazes 20 is small and is close to the wavelength of light, the light incident substantially parallel between the crazes as described above is reflected and scattered in reverse, while the light enters obliquely. Light is almost transmitted. Thereby, in the transparent resin film 10, the so-called visual field selectivity in which a case where the other side is seen through the film 10 and a case where the other side is not seen occurs depending on the viewing angle in the region of the craze 20 is expressed. That is, this visual field selectivity is exhibited by the single polymer resin film 10 itself. The range of the visual field selectivity varies depending on the craze depth in the thickness direction of the polymer resin film 10, the difference in the thickness of the polymer resin film 10 itself, and the like.

Next, in the field-selective film according to the second aspect, an additive layer (not shown) is provided in the craze 20 region.
Is provided, in addition to the function of the invention according to claim 1, a function according to the type of additive such as a coloring agent and a stabilizer contained in this additive layer is exhibited. That is, when the additive is a colorant, a color variation according to the use of the polymer resin film 10 can be obtained, and transmission of light can be suppressed. When the additive is an ultraviolet absorber,
By absorbing ultraviolet rays, the polymer resin film 10
Prevents deterioration and discoloration of itself. When the additive is a stabilizer, it suppresses the decomposition of molecules and the like. These functions improve the durability of the polymer resin film 10 itself. When the additive is a plasticizer, the polymer resin film 10 is plasticized to improve its flexibility. Further, when the additive is a flame retardant, the flame retardancy of the polymer resin film 10 itself is improved by shutting off air due to melting of the flame retardant and generating incombustible gas due to thermal decomposition of the flame retardant.

Next, in a method of manufacturing a field-selective film according to a third aspect, as shown in FIG. 5, a transparent polymer resin film 10 is bent substantially in parallel with its molecular orientation direction, and a local Since the typical bent portion 11 is formed, craze 20 is generated in the bent portion 11 of the polymer resin film 10 substantially in parallel with the molecular orientation direction. The reason that the polymer resin film 10 is bent substantially parallel to the molecular orientation direction is that the craze 20 is easily generated in the molecular orientation direction.

Further, since the polymer resin film 10 is pulled in the bending direction while maintaining the bent state, the polymer resin film 10 has a substantially same orientation as its molecular orientation as shown in FIGS. Parallel and continuous striped craze 20 regions are easily formed. Also Craze 2
The reason why the zero region is formed in a stripe shape is that stress concentration occurs at the bent portion 11, thereby causing buckling and craze 20. At this time, the stress concentration is caused by the craze 2 of the bent portion 11.
And the polymer resin film 10
This is because the film itself does not break and shifts at a constant speed.

In the method for manufacturing a field-selective film according to the fourth aspect, as shown in FIG. 6 or FIG. Presses the support 40 at an acute angle, so that a local bent portion 11 is formed substantially parallel to the molecular orientation direction of the polymer resin film 10. Crazes 20 are generated in the bent portions 11. The polymer resin film 1 formed by pressing the support 40
The angle of the bent portion 11 of the polymer resin film 1
It may be arbitrarily selected according to the thickness, hardness, etc. of zero.

Further, the polymer resin film 10 is
By pulling the polymer resin film 10 in the bending direction while being in contact with the leading end 11 of the zero, a continuous striped craze 20 region is formed easily in the polymer resin film 10 substantially in parallel with the molecular orientation direction. At this time, the polymer resin film 10
By adjusting the tension in the tension state (hereinafter simply referred to as tension), the interval between the crazes and the width of the crazes themselves are adjusted as shown in FIG. 1 or FIG. The craze 20 in FIG. 1 occurs when the tension is 10 N, and FIG.
Are generated when the tension is 6N. This is clear from FIG. 10 of the measurement results described in the following examples.

In the visual field selectable film obtained by the production method according to the third and fourth aspects,
As shown in FIG. 14 of the measurement results described in Examples below, almost no decrease in tensile strength is observed. This is because the fibrils generated in the craze 20 bear the stress.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a visual field selective film and a method for producing the same according to the present invention will be described in detail with reference to the drawings.
This is a typical one, and the present invention is not limited by the present embodiment.

As shown in FIGS. 1 and 2, the field-selective film according to this embodiment has a thickness of 25 mm, which is generally commercially available.
A stripe-shaped craze 20 region having an interval of about 20 μm is provided substantially in parallel with the molecular orientation direction of the transparent polymer resin film 10 made of polyvinylidene fluoride (PVDF) having a thickness of μm. The craze 20 almost penetrates not only on the surface of the polymer resin film 10 but also in the thickness direction thereof, but stops partially in the thickness direction without penetrating partly. In this embodiment, as the transparent polymer resin film 10, polyvinylidene fluoride is employed. However, other than this as long as the craze 20 can be formed, for example, polystyrene, polyethylene, polypropylene, polyester, polyamide, etc. May be adopted. Polyvinylidene fluoride has a wide operating temperature range from low to high temperatures, has flexibility and excellent mechanical properties, and has very good weather resistance, and its transparency and flexibility remain unchanged even when exposed outdoors for 10 years. Furthermore, it has excellent chemical resistance. Therefore, when the polymer resin film 10 is used for applications requiring these conditions, it is desirable to use polyvinylidene fluoride.

Next, an embodiment of the method for producing this visual field selective film will be described below. First, as shown in FIG. 5, a transparent polymer resin film 10 made of polyvinylidene fluoride having a thickness of 25 μm is bent substantially in parallel with the molecular orientation direction to form a locally bent portion 11 there. The upper and lower surfaces of the bent polymer resin film 10 are pressed by the pressing body 30. Next, by moving the pressing body 30 left and right (in the direction of the arrow), the polymer resin film 10 is pulled in the bending direction. As a result, as shown in FIGS. 1 and 2, continuous stripe-shaped craze 20 regions are formed substantially parallel to the molecular orientation direction of the polymer resin film 10. The craze 20 is alleviated and disappeared by heat-treating the film 10, and is generated by pulling the film. If a non-slip process is performed on the contact surface of the pressing body 30 with the polymer resin film 10, the surface of the polymer resin film 10 is fixed in close contact with the pressing body 30, so that when the film 10 is pulled, This can be securely held. As the non-slip processing, for example, styrene butadiene rubber (SB
R), rubber such as nitrile butadiene rubber (NBR), or polyurethane resin or the like formed in dots,
What is necessary is to adopt a material in which a double-sided adhesive tape or the like is attached to the surface of the pressing body 30. The pressure of the pressing body 30 may be arbitrarily selected according to the type and thickness of the polymer resin film.

Another embodiment of the method for producing a visual field selective film according to the present invention will be described below. FIG.
Alternatively, as shown in FIG. 7, in this embodiment, an auxiliary tool (hereinafter simply referred to as an auxiliary tool) 50 that moves up and down by a spring and a screw to adjust the tension of the polymer resin film 10, and a distal end portion 41 has an acute angle support. A crazing device with body 40 is used. First, the thickness 25μ held in tension
m, the tip 41 of the support 40 is pressed against the surface of the transparent polymer resin film 10 made of polyvinylidene fluoride to bend it.
0 is given a constant tension by an auxiliary tool, and the polymer resin film 10 is pulled in the direction of the arrow while contacting the support 40. As a result, as shown in FIGS. 1 and 2, a continuous craze 20 region is formed substantially parallel to the molecular orientation direction of the polymer resin film 10. By changing the tension, the interval between the crazes 20 and the width of the crazes 20 themselves can be adjusted as shown in FIG. 1, FIG. 2 or FIG.

As described above, when the polymer resin film 10 is pulled, for example, a winding machine (not shown) having a winding roller may be employed. Tip 41 of support 40
The bending angle of the polymer resin film 10 may be arbitrarily selected, and the bending angle of the polymer resin film 10 may be adjusted by moving the auxiliary tool 50 up and down, adjusting the height of the support 41 itself, or adjusting the height of the polymer resin film 10.
May be arbitrarily selected by changing the pulling angle of the tire.
Further, the support 40 may be fixed by attaching a roller (not shown) rotatably supported to the tip end portion 41 thereof. Since the roller freely rotates in accordance with the movement of the polymer resin film 10, the surface of the film 10 is prevented from being damaged.

The field-selective film according to the present invention may be provided with an additive layer (not shown) such as a colorant and a stabilizer in the craze 20 region. In this case, the craze 20 itself is composed of a molecular flux and a void, and has a structure similar to that of a sponge as a whole. Therefore, a coloring agent such as a dye, an organic pigment, or an inorganic pigment is used as the craze 2.
By penetrating into 0, an additive layer is formed. As the colorant, those excellent in dispersibility, heat resistance, weather resistance, water resistance, chemical resistance and the like are desirable. Examples of the colorant include oil-soluble dyes as dyes, azo-based, phthalocyanine-based, anthraquinone-based, and quinacridone-based organic pigments, and inorganic pigments such as oxides, sulfides, lead chromate, ferrosyanides, and silicates. And carbon black. In addition to the coloring agent, the additive layer may further include an ultraviolet absorber such as benzotriazole and 2-hydroxy-4-methoxy-benzophenone, a flame retardant such as a phosphate ester and a halogenated hydrocarbon, an inorganic lead, a metal soap, an organic soap. A stabilizer such as a tin compound and a plasticizer such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP) can be contained.

With respect to the field-selective film of the present invention thus obtained, the transmitted light intensity is measured by a laser, the diffraction intensity is measured by a laser, the distance between the crazes and the width of the crazes themselves are measured, and the tensile strength is measured. Were measured, the following results were obtained.

First, the transmitted light intensity by the laser is measured. As shown in FIG. 8, a sample having a thickness of 25 μm, a width of 10 mm, and a length of 20 mm is fixed between two slide glasses. Next, Laser 60 (He-Ne laser NEO-15MS) manufactured by Nippon Kagaku Engineering Co., Ltd.
, A rotary disk 70 with a scale, and a light meter 80 (laser power meter PM manufactured by Nippon Kagaku Engineering Co., Ltd.)
-210) is arranged so that the laser beam is vertically applied to the center of the light receiving section 90 of the light meter 80, and the sample is irradiated so that the laser beam is applied vertically, and the rotating disk 70 is rotated by 5 ° from 0 ° to 60 °. To record the intensity change of the transmitted light entering the light receiving unit 90. The measurement is performed by covering the light-receiving unit 90 so as not to receive the scattered light by the sample and making a hole having a diameter of 0.46 mm at the center thereof. Based on the obtained data, the horizontal axis represents the incident angle and the vertical axis represents the transmitted light intensity ratio, and a graph is created. However, as the samples, those having a polymer resin film tension of 8, 10, and 12 (N) at the time of manufacture were used.

The result shown in FIG. 13 was obtained by this measurement. It is apparent from FIG. 13 that the transmitted light intensity ratio changes with the change in the incident angle of the laser light, and it can be seen from this that visual field selectivity is developed.

Next, the diffraction intensity by the laser is measured. As shown in FIG. 9, a laser 60 is arranged and fixed so that the laser beam irradiates the sample vertically. When the sample is irradiated with laser light, a diffraction image appears. The intensity of the laser beam is recorded while moving the light receiving section 90 to the center of the diffraction image in left and right steps at intervals of 1 mm. Based on the obtained data, a graph is created with the horizontal axis representing the moving distance and the vertical axis representing the diffraction intensity, and the distance from the center peak to the next peak is determined. However, as the samples, those having a polymer resin film tension of 6 N and 10 N at the time of production were used, respectively.

From the above results, the interval (d) between the crazes is obtained using the following equation. dsi θ = λ where θ is the diffraction angle and λ is the wavelength of the laser light (λ = 0.
6328 μm).

By this measurement, the results shown in FIGS. 11 and 12 were obtained. From these results and the above formula, the distance between the crazes was calculated. As a result, the sample having a tension of 6N was 21.1 μm and the sample having a tension of 10N was 19.0.
μm was obtained. This number is approximately the same as the distance between the same crazes in FIG. 10 plus the width of the crazes themselves, which is equal to the space between the centers of the crazes themselves. FIG. 10 shows that the distance between the crazes and the width of the crazes themselves depend on the magnitude of the tension of the polymer resin film at the time of manufacture.

Then, the tensile strength of the field-selective film due to the formation of craze is measured. This measurement was performed by the following method. A sample having a thickness of 25 μm × length 15 mm × width 3 mm was attached to a tensile tester (not shown) manufactured by Toyo Baldwin Co., Ltd., and the tensile speed was 10 mm / min.
Pull until the sample breaks with. From the results of the tensile test, the tensile strength (σ) is determined using the following equation. σ = P / S where P is the maximum load applied to the sample, and S is the cross-sectional area of the sample.

From this measurement, the result shown in FIG. 14 was obtained. From FIG. 14, it can be seen that the tensile strength of the field-selective film hardly decreases due to the formation of craze.

[0032]

As described above, the following effects can be obtained by using the visual field selectable film and the method of manufacturing the same according to the present invention.

First, in the field-selective film according to the first aspect, the transparent polymer resin film is provided with a stripe-like craze region substantially parallel to the molecular orientation direction. The light incident substantially parallel between the light is transmitted, and the light incident obliquely is reflected and scattered. On the other hand, when the interval between the crazes is small and is close to the wavelength of the light, the light incident substantially parallel between the crazes as described above is reflected and scattered in reverse, while the light incident obliquely Is almost transparent. As a result, the polymer resin film may or may not be visible through the film depending on the viewing angle in the craze region. Therefore, since a single polymer resin film itself has field-of-view selectivity, it can be provided at lower cost than a conventional plate glass with an organic polymer film or a resin composition coated on a substrate. Further, the visual field selectable film according to the present invention can be used for applications requiring various visual field selectivities such as window glass blinds.

Next, in the visual field selective film according to the second aspect, since the additive layer is provided in the craze region, the additive layer is contained in this additive layer in addition to the effect of the first aspect. Functions according to the types of additives such as colorants and stabilizers are exhibited. That is, when this additive is a colorant, color variation according to the use of the polymer resin film can be obtained, and light transmission can be suppressed. When the additive is an ultraviolet absorber, the polymer resin film itself can be prevented from being deteriorated or discolored by absorbing ultraviolet light. If the additive is a stabilizer,
Decomposition of molecules and the like can be suppressed. These functions can improve the durability of the polymer resin film itself. When the additive is a plasticizer, the polymer resin film is plasticized, so that its flexibility can be improved. Further, when the additive is a flame retardant, the flame retardancy of the polymer resin film itself can be improved by shutting off air due to melting of the flame retardant, generating incombustible gas by thermal decomposition of the flame retardant, and the like. Therefore, in this visual field selectable film, these optional functions can be obtained as needed.

Next, in a method of manufacturing a field-selective film according to a third aspect, a transparent polymer resin film is bent substantially parallel to the molecular orientation direction to form a local bent portion there. Therefore, craze occurs in the bent portion substantially in parallel with the molecular orientation direction. Then, by simply pulling this polymer resin film, a continuous stripe-like craze region can be easily formed in the film substantially parallel to the molecular orientation direction. Therefore, in the method for producing a field-selective film according to the present invention, unlike the conventional method, there is no need to apply an organic polymer film or apply a resin composition, and does not go through complicated steps.
Excellent productivity. Further, even if the craze region is formed, the field-selective film hardly reduces the tensile strength, so that it can be used for various applications without worry.

In the method for manufacturing a field-selective film according to claim 4, the support having an acute end is pressed against the surface of the transparent polymer resin film held in a tensioned state. A local bent portion is formed substantially parallel to the molecular orientation direction of the polymer resin film, and craze occurs at the bent portion. Then, by simply pulling the polymer resin film in the bending direction while contacting the tip of the support, the film can easily form a continuous striped craze region substantially parallel to the molecular orientation direction. Can be. At this time, since the tension of the polymer resin film in the tension state can be adjusted, the interval between the crazes and the width of the crazes themselves can be adjusted. Therefore, according to the method for manufacturing a field-selective film according to the present invention, the range of the field-selectivity of the film can be arbitrarily selected. Further, even if the craze region is formed, the field-selective film hardly reduces the tensile strength, so that it can be used in various applications without worry.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view of a main part showing one embodiment of a visual field selective film according to the present invention.

FIG. 2 is a main part enlarged plan view showing another embodiment of the visual field selective film according to the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part showing a state in which light is incident on a visual field selective film according to the present invention.

FIG. 4 is an enlarged cross-sectional view of a main part showing a state where light incident angles are different in FIG.

FIG. 5 is a front view showing one embodiment of the method for producing a visual field selective film according to the present invention.

FIG. 6 is a front view showing another embodiment of the method for producing a visual field selective film according to the present invention.

FIG. 7 is an enlarged front view showing the vicinity of a support in FIG. 6;

FIG. 8 is a front view of an apparatus for measuring transmitted light intensity by a laser.

FIG. 9 is a front view of an apparatus for measuring diffraction intensity by a laser.

FIG. 10 is a graph showing the interval between comrades and the width of the crazes themselves.

FIG. 11 is a graph showing diffraction intensity by laser.

FIG. 12 is another graph showing the diffraction intensity by laser.

FIG. 13 is a graph showing the intensity of light transmitted by a laser.

FIG. 14 is a graph showing tensile strength.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High polymer resin film 11 Folded part 20 Craze 40 Support body 41 Front-end | tip part 100 The visual field selectable film which concerns on this invention

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-77001 (JP, A) JP-A-3-156402 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 5/00 C08J 5/18

Claims (4)

(57) [Claims] 1. A field-selective film, wherein a transparent polymer resin film is provided with a striped craze region substantially parallel to the molecular orientation direction of the polymer resin film. 2. The field-selective film according to claim 1, wherein an additive layer is provided in the craze region. 3. A transparent polymer resin film is bent substantially in parallel with the molecular orientation direction of the polymer resin film to form a local bent portion, and then the polymer resin film is bent. The bending line at
And forming a continuous striped craze region substantially parallel to the molecular orientation direction of the polymer resin film by pulling in a direction perpendicular to the polymer resin film. 4. The polymer resin film is bent substantially parallel to its molecular orientation by pressing a support having an acute end portion against the surface of the transparent polymer resin film held in tension. Forming a local bend,
Thereafter, the polymer resin film is brought into contact with the tip of the support while
A continuous stripe-like craze region substantially parallel to the molecular orientation direction of the polymer resin film by pulling in a direction perpendicular to the polymer resin film.