JP6951688B2 - A craze film, a film for forming a craze, and a method for producing a craze film. - Google Patents

Description

[Cross-reference of related applications]
The present application claims the benefit of priority under Japanese Patent Application No. 2017-0253559 filed on February 14, 2017. The disclosure of the Japanese patent application shall be included in the present application in its entirety by reference.

[Technical field of invention]
The present invention relates to a craze film, a film for forming a craze, and a method for producing a craze film.

Conventionally, there is a craze film in which linear crazes are formed in stripes. Conventionally, the craze film is generally obtained by bending a polymer resin film having a molecular orientation in parallel with the molecular orientation direction using a processing blade such as a blade, and applying tension in that state to the molecular orientation direction. It is manufactured by taking it in the vertical direction and forming a continuous striped craze substantially parallel to the molecular orientation direction.

However, in the T-die method and the inflation method, which are the most common film manufacturing methods, it is difficult to strongly align the molecules perpendicular to the flow direction of the extruded molten resin, and the craze becomes perpendicular to the flow direction. It cannot be continuously produced and processed.

Therefore, conventionally, a technique using a laterally uniaxially stretched film that is uniaxially stretched perpendicular to the film flow direction is known (see, for example, Patent Document 1). However, in order to industrially produce a laterally uniaxially stretched film, it is necessary to introduce a large and complicated stretching device (a device generally called a film tenter or the like) which is generally expensive. Moreover, when the end portion of the unstretched raw fabric is held by a tenter clip and laterally stretched, the holding portion and the portion in the vicinity thereof do not have a desired thickness and quality, and a constant amount of loss is continuously generated. Therefore, there is a problem that the productivity is low and the cost is high.

On the other hand, Patent Document 2 discloses a craze-formed unstretched film containing a crystalline thermoplastic resin but having an amorphous state and having crazes formed therein (in particular, claim). 1). Further, as an effect, it is described that since the stretching step is not performed, a craze film can be easily and effectively obtained by a general film manufacturing extruder without the need for a stretching device (particularly, paragraph []. 0014]).

Japanese Unexamined Patent Publication No. 08-085161 Japanese Unexamined Patent Publication No. 2014-224181

Patent Document 2 discloses applications of the craze film, such as prevention of peeping on a liquid crystal screen of a mobile phone, generation of microbubbles, and air bleeding of a water purifier. In addition, the peep prevention film utilizes the scattering of light by the craze and the blind effect by the periodic craze, and the micro-bubble generating film and the air bleeding film have fine continuous holes through which the craze penetrates in the thickness direction of the film. It is disclosed that it is using something.

On the other hand, Patent Document 2 does not describe the use of a craze film to deflect light, nor does it describe increasing the amount of light deflected by the craze (hereinafter, also referred to as "deflection light amount"). Note that the deflection means that the traveling direction changes when the incident light is emitted from a surface (emission surface) opposite to the incident surface.

Further, the craze-formed unstretched film of Patent Document 2 is considered to have a low elastic modulus and a high breaking point elongation because the molecules to be crystallized are in an amorphous state and contain a large amount of amorphous portions. Therefore, it is difficult to form a craze that increases the amount of polarized light.
That is, according to the study by the present inventors, it has been found that one condition is that the distance between adjacent crazes is within a specific range in order to increase the amount of polarized light. Since the craze-formed unstretched film of No. 2 has a low elastic modulus and a high breaking point elongation, it is difficult to set the craze interval so that the amount of deflected light can be increased. Patent Document 2 does not describe how much the adjacent crazes are spaced apart from each other.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a craze film capable of increasing the amount of light deflected by the craze. It also provides a film for forming a craze that can be suitably used for producing the craze film. It also provides a method for producing the craze film.

The present inventors have diligently studied the craze film. As a result, it was surprisingly found that the resin layer containing the crystalline polystyrene-based resin can form a craze capable of increasing the amount of polarized light in the unstretched state. The present invention has been completed.

That is, the craze film according to the present invention is
The craze extending in a certain direction has a resin layer formed in stripes, and has a resin layer.
The resin layer contains a crystalline polystyrene-based resin and is unstretched.
The deflected light fraction Rr ₃₀ measured by the following method for measuring the deflected light fraction Rr ₃₀ is 15 to 65%.

<Measuring method of polarized light fraction Rr _30>
(1) A light source capable of changing the incident angle of light with respect to the irradiation position and a light receiving position located on the opposite side of the light source with the irradiation position sandwiched between them and capable of changing the angle with respect to the irradiation position. A measuring device including the unit is prepared, and the craze film is set so that the direction of the craze is vertical with respect to the angle-changeable surface of the light source and the light receiving unit.
(2) Light is irradiated from the light source to one surface of the craze film at an incident angle θ ₁ = 30 °.
(3) When the vertical direction of the craze film is 0 °, the angle α of the light receiving portion is moved from + 90 ° to −90 °, and the amount of emitted light is measured at 1 ° intervals. Of these, the total of the measured values at 90 points from -1 ° to −90 ° is defined as the deflection light amount Rd ₃₀ . The angle α represents the side including the position of the light source and the surface object with respect to the craze film surface as a minus.
(4) The same measurement is performed without setting the craze film, and the total of the measured values at 181 points from + 90 ° to −90 ° is defined as the initial integrated light intensity Ri ₃₀ .
(5) The deflection light fraction Rr ₃₀ (%) = (Rd ₃₀ / Ri ₃₀ ) × 100.

According to the above configuration, the resin layer is unstretched and has not undergone the stretching step, so that the stretching step can be omitted, which is excellent in manufacturing efficiency. Moreover, since a stretching device is not required, the burden of introducing the device is small.
Further, the craze film has a deflection light fraction Rr ₃₀ of 15 to 65%. Since the deflection light fraction Rr ₃₀ is 15 to 65%, it is possible to increase the amount of light deflected for the incident light at _{an incident angle θ 1 = 30 °.}

In the above configuration, the deflection light fraction Rr ₅₀ measured by the following method for measuring the deflection light fraction Rr ₅₀ is preferably 5 to 55%.

<Measuring method of polarized light fraction Rr _50>
(6) A light source capable of changing the incident angle of light with respect to the irradiation position and a light receiving position located on the opposite side of the light source with the irradiation position sandwiched between them and capable of changing the angle with respect to the irradiation position. A measuring device including the unit is prepared, and the craze film is set so that the direction of the craze is vertical with respect to the angle-changeable surface of the light source and the light receiving unit.
(7) Light is irradiated from the light source to one surface of the craze film at an incident angle θ ₁ = 50 °.
(8) When the vertical direction of the craze film is 0 °, the angle α of the light receiving portion is moved from + 90 ° to −90 °, and the amount of emitted light is measured at 1 ° intervals. Of these, the total of the measured values at 90 points from -1 ° to −90 ° is defined as the deflection light amount Rd ₅₀ . The angle α represents the side including the position of the light source and the surface object with respect to the craze film surface as a minus.
(9) The same measurement is performed without setting the craze film, and the total of the measured values at 181 points from + 90 ° to −90 ° is defined as the initial integrated light intensity Ri ₅₀ .
(10) The deflection light fraction Rr ₅₀ (%) = (Rd ₅₀ / Ri ₅₀ ) × 100.

When the deflection light fraction Rr ₅₀ is 5 to 55%, it is possible to increase the amount of light deflected with respect to the incident light at _{an incident angle θ 1 = 50 °.}

In the above configuration, the average value _{L C} interval _{L C} between adjacent craze 'is preferably in the range of 10 to 40 [mu] m. If the average value of the distance L _C between adjacent craze between L _{C 'is} within the above range, it is possible to increase the more deflection amount.

Further, the film for forming a craze according to the present invention is
Has a resin layer
The resin layer contains a crystalline polystyrene-based resin and is unstretched.
The tensile elastic modulus in the flow direction (MD) of the resin layer is 2.0 GPa or more and 3.2 GPa or less, and the breaking point elongation in the flow direction (MD) of the resin layer is 0.2% or more and 30% or less. It is characterized by that.

As described above, the present inventors have stated that the resin layer containing the crystalline polystyrene-based resin can form a craze capable of increasing the amount of polarized light in the unstretched state. I found it. The present inventors presume that the reason is that the unstretched resin layer containing the crystalline polystyrene-based resin has high elasticity and low breaking point elongation. That is, if the elasticity is low, the amount of deflected light is small because the crazes are difficult to form or the intervals between the formed crazes are wide, but the amount of deflected light is large because of the high elasticity. We believe that it will be possible to form crazes at appropriate intervals and depths. Further, if the elongation at the breaking point is high, the craze does not enter properly when the processing blade is applied, and the resin layer is stretched. However, since the low elongation at the breaking point is relatively small, the resin layer does not stretch. I think that the craze will enter properly.
According to the above configuration, the tensile elastic modulus in the flow direction (MD) of the resin layer is 2.0 GPa or more and 3.2 GPa or less, and the breaking point elongation in the flow direction (MD) of the resin layer is 0.2%. More than 30% or less. Therefore, by using the craze forming film, it is possible to form a craze capable of increasing the amount of deflected light.

Further, the method for producing a craze film according to the present invention is as follows.
Step A to prepare the film for forming a craze, and
The craze-forming film is pressed against the edge portion of the processing blade to form a bent portion on the craze-forming film, and the bent portion is moved relative to the craze-forming film. It is characterized by having a step B of forming crazes in a striped shape on the resin layer.

According to the above configuration, the tensile elastic modulus in the flow direction (MD) of the resin layer is 2.0 GPa or more and 3.2 GPa or less, and the breaking point elongation in the flow direction (MD) of the resin layer is 0.2% or more 30. A craze forming film of% or less is used to form a craze on the resin layer. Therefore, in the produced craze film, crazes capable of increasing the amount of deflected light are formed.

_{In the above configuration, it is preferable that the angle θ 2} formed by the craze forming film at the bent portion is 15 ° to 160 °, and the tip shape of the edge portion is hemispherical with a radius of 1 mm or less.

When the angle θ _{2 is set} to 15 ° to 160 ° and the tip shape of the edge portion is hemispherical with a radius of 1 mm or less, it is possible to easily form a craze capable of increasing the amount of deflected light.

According to the present invention, it is possible to provide a craze film capable of increasing the amount of light deflected by the craze. Further, it is possible to provide a film for forming a craze that can be suitably used for producing the craze film. In addition, a method for producing the craze film can be provided.

It is a perspective view which shows typically the craze film which concerns on one Embodiment. It is a perspective view which shows typically the craze film which concerns on other embodiment. It is the schematic schematic diagram of the measuring apparatus for measuring the polarized light fraction. It is a schematic diagram for demonstrating the appearance of using a craze film as a daylighting film. It is another schematic diagram for demonstrating the appearance of using a craze film as a daylighting film. It is a perspective view which shows typically the film for forming a craze which concerns on one Embodiment. It is a perspective view which shows typically the film for forming a craze which concerns on other embodiment. It is a perspective view for demonstrating the manufacturing method of the craze film which concerns on one Embodiment. It is a side view of the craze forming apparatus shown in FIG. (A) is a schematic diagram of a measuring device used for evaluating the ceiling illuminance, (b) is a diagram for explaining the position and size of the window W, and (c) is a ceiling illuminance measuring position. , And a diagram for explaining the size. It is a schematic diagram at the time of installing a craze film in the evaluation of the ceiling illuminance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments.

(Clays film)
FIG. 1 is a perspective view schematically showing a craze film according to an embodiment. FIG. 2 is a perspective view schematically showing a craze film according to another embodiment.

In the craze film according to the present embodiment, crazes extending in a certain direction are formed in stripes. In the craze film 10 shown in FIG. 1, a plurality of crazes 14 extending linearly or substantially linearly in the lateral direction (TD) of the craze film 10 are formed, and the plurality of crazes 14 are formed parallel to or substantially parallel to each other. Has been done. Further, in the craze film 11 shown in FIG. 2, a plurality of crazes (combined crazes 14 and 16) extending linearly or substantially linearly in the lateral direction (TD) of the craze film 11 are formed. The plurality of crazes are formed parallel to or substantially parallel to each other. That is, the striped formation means that a plurality of crazes are formed in parallel or substantially parallel to each other. In the craze film 10 and the craze film 11, a case where each craze is formed so as to extend in the lateral direction (TD) will be described. However, in the present invention, the craze is formed if it is formed in a striped shape. The direction is not particularly limited.

The craze film according to this embodiment has a deflection light fraction Rr ₃₀ measured by the following method for measuring the deflection light fraction Rr ₃₀ of 15 to 65%. The deflection light fraction Rr ₃₀ is preferably 15 to 60%, more preferably 20 to 55%, further preferably 25 to 50%, and particularly preferably 30 to 45%. preferable.

The craze film preferably has a deflection light fraction Rr ₅₀ measured by the following method for measuring the deflection light fraction Rr _{50 of 5} to 55%. The deflection light fraction Rr ₅₀ is more preferably 10 to 50%, further preferably 20 to 48%, and particularly preferably 30 to 45%.

In addition, in this invention, "the deflection light fraction Rr ₃₀ measured by the measuring method of the deflection light fraction Rr ₃₀ is 15-65%" is said.
(X) A value measured by irradiating the surface of the processing blade where the edge portion was not pressed with light from a light source during the craze processing.
(Y) A value measured by irradiating the surface on which the edge of the processing blade is pressed with light from a light source during the craze processing.
At least one of them is 15 to 65%.
Similarly, in the present invention, "the deflection light fraction Rr ₅₀ measured by the method for measuring the deflection light fraction Rr ₅₀ is 5 to 55%" is defined as.
(X) A value measured by irradiating the surface of the processing blade where the edge portion was not pressed with light from a light source during the craze processing.
(Y) A value measured by irradiating the surface on which the edge of the processing blade is pressed with light from a light source during the craze processing.
At least one of them is 5 to 55%.

Hereinafter, a method for measuring the deflected light fraction Rr ₃₀ and the deflected light fraction Rr ₅₀ of the craze film will be described. _{In the following, the method of measuring the deflection light fraction Rr 30} and the deflection light fraction Rr ₅₀ will be described by taking the craze film 10 as an example, but the same applies regardless of the layer structure of the craze film. And measure. For example, when measuring the deflection light fraction Rr ₃₀ and the deflection light fraction Rr ₅₀ for the craze film 11, the craze film 11 is set at a predetermined position instead of the craze film 10 for measurement.

FIG. 3 is a schematic schematic diagram of a measuring device for measuring the deflection light fraction. As shown in FIG. 3, the measuring device 30 is located on the side opposite to the light source 34 with the light source 34 capable of changing the incident angle of light with respect to the irradiation position 32 and the irradiation position 32 in between, and the irradiation position. A light receiving unit 36 capable of changing the angle with respect to 32 is provided.

<Measuring method of polarized light fraction Rr _30>
(1) The measuring device 30 is prepared, and the craze film 10 is set so that the direction of the craze 14 is vertical with respect to the angle-changeable surfaces of the light source 34 and the light receiving unit 36.
(2) Light is irradiated from the light source 34 to one surface 10a of the craze film 10 at an incident angle θ ₁ = 30 °.
(3) When the vertical direction of the craze film 10 is 0 °, the angle α of the light receiving portion 36 is moved from + 90 ° to −90 °, and the amount of emitted light is measured at 1 ° intervals. Of these, the total of the measured values at 90 points from -1 ° to −90 ° is defined as the deflection light amount Rd ₃₀ . The angle α represents the side including the position of the light source 34 and the surface object with respect to the surface of the craze film 10 (in FIG. 3, the upper left side of the craze film 10) as a minus.
(4) The same measurement is performed without setting the craze film 10, and the total of the measured values at 181 points from + 90 ° to −90 ° is defined as the initial integrated light intensity Ri ₃₀ .
(5) The deflection light fraction Rr ₃₀ (%) = (Rd ₃₀ / Ri ₃₀ ) × 100.

<Measuring method of polarized light fraction Rr _50>
(6) The measuring device 30 is prepared, and the craze film 10 is set so that the direction of the craze 14 is vertical with respect to the angle-changeable surfaces of the light source 34 and the light receiving unit 36.
(7) Light is irradiated from the light source 34 to one surface 10a of the craze film 10 at an incident angle θ ₁ = 50 °.
(8) When the vertical direction of the craze film 10 is 0 °, the angle α of the light receiving portion 36 is moved from + 90 ° to −90 °, and the amount of emitted light is measured at 1 ° intervals. Of these, the total of the measured values at 90 points from -1 ° to −90 ° is defined as the deflection light amount Rd ₅₀ . The angle α represents the side including the position of the light source 34 and the surface object with respect to the surface of the craze film 10 (in FIG. 3, the upper left side of the craze film 10) as a minus.
(9) The same measurement is performed without setting the craze film 10, and the total of the measured values at 181 points from + 90 ° to −90 ° is defined as the initial integrated light intensity Ri ₅₀ .
(10) The deflection light fraction Rr ₅₀ (%) = (Rd ₅₀ / Ri ₅₀ ) × 100.

Since the deflection light fraction Rr ₃₀ is 15 to 65%, it is possible to increase the amount of light deflected for the incident light at _{an incident angle θ 1 = 30 °.}
Further, when the deflection light fraction Rr ₅₀ is 5 to 55%, it is possible to increase the amount of light deflected for the incident light at _{an incident angle θ 1 = 50 °.} That is, when the deflected light fraction Rr ₃₀ is 15 to 65% and the deflected light fraction Rr ₅₀ is 5 to 55%, the _{incident light at an incident angle θ 1} = about 30 ° and the incident light. It is possible to increase the amount of light deflected by the light incident at an incident angle θ _{1 = 50 °.}

The layer structure of the craze film according to the present embodiment is not particularly limited as long as it has at least a resin layer. In the present specification, the "resin layer" refers to a layer containing a crystalline polystyrene-based resin and which is not stretched, and is a layer capable of forming a craze.
The craze film according to the present embodiment may be composed of only a resin layer, may be composed of a resin layer and another resin layer, or may be composed of a resin layer and other layers. It may be composed of a resin layer, another resin layer, and another layer. In the present specification, the "other resin layer" is a layer that does not correspond to a resin layer (a layer containing a crystalline polystyrene-based resin and not stretched), and is a layer capable of forming a craze. Further, the "other layer" is a layer in which craze cannot be formed.

In the craze film according to the present embodiment, the stacking order of the resin layer, the other resin layer, and the other layers is not particularly limited. Further, the resin layer, the other resin layer, and the other layer may be a single layer or two or more layers, respectively. When at least one of the resin layer, the other resin layer, and the other layer is two or more layers, another layer may be interposed between the first layer and the second layer, and the first layer may be interposed. The layer and the second layer may be in contact with each other. Specifically, for example, when the other resin layer is formed into two layers, the first other resin layer, the resin layer, and the second other resin layer may be laminated in this order. The first other resin layer and the second other resin layer may be laminated in this order.

The craze film 10 shown in FIG. 1 is composed of one layer of the resin layer 12. The craze film 11 shown in FIG. 2 has a configuration in which a resin layer 12, another resin layer 15, and other layers 17 are provided in this order.

When the craze film is composed of only a resin layer (for example, the craze film 10 shown in FIG. 1), the craze film is unstretched. The resin layer is not particularly limited as long as it is unstretched, but it is preferably formed by melt extrusion and then not stretched. The resin layer may be formed by a solution casting method or a calendar method and then not stretched. Since the resin layer is unstretched and has not undergone a stretching step, it is excellent in manufacturing efficiency in that the stretching step can be omitted. Moreover, since a stretching device is not required, the burden of introducing the device is small.

Further, when the craze film includes a resin layer and another resin layer and / or other layer (for example, the craze film 11 shown in FIG. 2), the craze film is, for example, a resin layer and another resin layer and /. Alternatively, it can be formed by coextrusion with other layers. Further, the resin layer alone can be formed first by the above method, and the other resin layer and / or the other layer can be formed by extrusion or solution casting on the formed resin layer. Further, another resin layer and / or other layer can be formed first, and the resin layer can be formed by extrusion or solution casting on the layer. Further, it can be formed by direct lamination of a resin layer separately formed by extrusion or solution casting, etc., and another resin layer and / or other layer by heat or pressure, or by lamination via an adhesive or the like. ..
The other resin layer and the other layer may be unstretched, and if the method is such that the resin layer is not stretched, the other resin layer and the other layer are vertically uniaxially stretched, horizontally uniaxially stretched, diagonally uniaxially stretched, and sequentially. It may be a layer subjected to stretching such as biaxial stretching and simultaneous biaxial stretching.
From the viewpoint of production efficiency, the other resin layer and the other layer are preferably unstretched layers co-extruded with the resin layer.

The thickness of the craze film can be appropriately set so as to be a suitable thickness according to the purpose and application, but from the viewpoint of easily increasing the deflection light fraction, it is preferably 5 μm to 500 μm, and 10 μm to 10 μm. It is more preferably 300 μm, further preferably 15 μm to 150 μm, particularly preferably 20 μm to 100 μm, and particularly preferably 35 μm to 50 μm.
As a method of setting the thickness of the craze film within the above numerical range, a method of adjusting the thickness of the resin layer can be mentioned. However, in this case, as will be described later, the thickness of the resin layer is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, further preferably 15 μm to 90 μm, and 20 μm to 60 μm. It is particularly preferable that there is, and it is particularly preferable that it is 35 μm to 50 μm. Further, when the craze film has a structure having another resin layer and / or other layers in addition to the resin layer, the thickness of the resin layer is not adjusted or in addition to the adjustment of the thickness of the resin layer. , A method of adding another resin layer or another layer, or adjusting the thickness of the other resin layer or the other layer can be mentioned.

The width of each craze (width in the direction perpendicular to the processing blade) formed on the craze film according to the present embodiment is preferably 0.05 μm to 2 μm, and preferably 0.1 μm to 1.5 μm. It is more preferably 0.15 μm to 1 μm, further preferably 0.6 μm to 1 μm, and particularly preferably 0.65 μm to 0.95 μm. When the width is 0.05 μm or more, it becomes easy to deflect the light. On the other hand, when the width is 2 μm or less, the transparency of the film is less likely to decrease, which is preferable. The width of the craze means that 50% or more of the crazes formed on the craze film are within the numerical range. The craze width is measured by the method described in Examples.
The length of each craze (the length in the direction parallel to the processing blade) is approximately the same as the length of the processing blade, but it may be the same as the length in the width direction of the craze film. It may be shorter than the length in the width direction. When the length of the craze is shorter than the length in the width direction of the craze film, it is easy to prevent the film from breaking during craze formation. The length of the craze is preferably 500 μm or more.

In crazes film according to the present embodiment, the average value _{L C} interval _{L C} between adjacent craze ', when the thickness of the resin layer and T, _{L C'} value of / T is 0.20 to 0.80 It is preferably in the range of 0.25 to 0.60, more preferably in the range of 0.30 to 0.40.
The most preferred forms are within the scope thickness T of 20μm~60μm resin layer, the average value _{L C} interval _{L C} between adjacent craze 'is preferably in the range of 10 to 40 [mu] m, 13 It is more preferably in the range of ~ 30 μm, further preferably in the range of 15-19 μm.
A further most preferred embodiment is in the range thickness T of 35μm~50μm resin layer, the average value _{L C} interval _{L C} between adjacent craze 'is preferably in the range of 10 to 40 [mu] m, It is more preferably in the range of 13 to 30 μm, further preferably in the range of 15 to 19 μm.
Incidentally, the distance L _C refers to the center line of one of the crazing, the distance between the center line of the other craze (see FIGS. 1 and 2). If the average value of the distance L _C between adjacent craze between L _{C 'is} within the above range, it is possible to increase the more deflection light fraction. Mean value L _C interval L _C of adjacent craze each other _'is a value measured by a method described in the Examples.

In the craze film according to the present embodiment, the number of crazes per 500 μm length is preferably in the range of 15 to 45, more preferably in the range of 20 to 40, and 26 to 35. It is more preferably within the range. When the number of crazes per 500 μm in length is within the above range, the deflection light fraction can be further increased. The number of crazes per 500 μm in length is a value measured by the method described in Examples.

In the craze film according to the present embodiment, the fine craze interval ratio is preferably in the range of 0 to 30%, more preferably in the range of 5 to 25%, and in the range of 10 to 18%. It is more preferable to have. When the fine craze interval ratio is within the above range, the deflection light fraction can be further increased.
The fine craze interval ratio is the number of creas whose value L is 10 μm or less when the number of crazes per 500 μm in length is measured (when an abnormal value is excluded, the corresponding number after excluding the abnormal value). The ratio divided by the number of crazes per 500 μm in length is expressed as a percentage, and is a value measured by the method described in Examples.

The depth D (μm) of each craze formed on the craze film according to the present embodiment is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, based on the thickness of the resin layer. .. The depth of each craze formed on the craze film according to the present embodiment may be 100% with respect to the thickness of the resin layer. When the depth of each craze is in each of the above-mentioned preferable ranges, it becomes easy to deflect the light. The method for measuring the craze depth D is as described in the examples. As an example of the depth of each craze, the depth D (μm) of each craze is preferably 40 μm or more, more preferably 42.5 μm or more, and further preferably 45 μm or more.
The aspect ratio of each craze formed in craze film according to the present embodiment (i.e., _{L C} '/ D) is preferably from 0.05 to 0.55, more preferably 0.10 to 0.41, 0 It is more preferably .25 to 0.40, and particularly preferably 0.30 to 0.37. When the aspect ratio of each craze is in each of the above-mentioned preferable ranges, it becomes easy to deflect the light.

In the craze film according to the present embodiment, the components existing in the voids (pores) of the craze are not particularly limited as long as the effects of the present invention are exhibited. For example, the component existing in the void (pore) of the craze may be a gas such as air, or may be filled with additives such as a colorant, a dye, a stabilizer, and a conductive polymer. It is preferably a gas (particularly air).

The craze film according to the present embodiment preferably has a tensile elastic modulus in the flow direction (MD) of 1.7 GPa or more and 2.8 GPa or less, and more preferably 1.8 GPa or more and 2.7 GPa or less. When the tensile elastic modulus is 1.7 GPa or more, it is possible to form crazes on the film before the craze treatment at a relatively narrow interval and depth such that the amount of deflected light increases. Further, when the tensile elastic modulus is 2.8 GPa or less, it is possible to prevent the film from breaking without forming crazes on the film before the craze treatment. The tensile elastic modulus is a value measured under the conditions described in the examples.

The craze film according to the present embodiment preferably has a breaking point elongation in the flow direction (MD) of 1% or more and 15% or less, more preferably 1.5% or more and 10% or less, and 2% or more. It is more preferably 4% or less. When the breaking point elongation is 15% or less, the film before the craze treatment does not stretch and the craze can be formed appropriately. Further, when the breaking point elongation is 1% or more, it is possible to prevent the film before the craze treatment from breaking without forming the craze. The breaking point elongation is a value measured at 23 ° C. under the conditions described in Examples.

In the craze film according to the present embodiment, the breaking point stress in the flow direction (MD) is preferably 18 MPa or more and 60 MPa or less, and more preferably 30 MPa or more and 50 MPa or less. When the breaking point stress is 18 MPa or more, it is possible to prevent the film from breaking without forming crazes before the craze treatment. Further, when the breaking point stress is 60 MPa or less, it is easy to form crazes on the film appropriately and it is easy to increase the deflection light fraction. The breaking point stress is a value measured at 23 ° C. under the conditions described in the examples.

The craze film according to the present embodiment has translucency, and specifically, the total light transmittance is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more. The total light transmittance may be less than 100%, preferably 98% or less. Within the above range, it is easy to obtain a preferable polarized light fraction.

Hereinafter, the resin layer, the other resin layer, and the other layer will be described with reference to the craze film 10, the resin layer 12 included in the craze film 11, the other resin layer 15, and the other layer 17. However, the resin layer 12, the other resin layer 15, and the other layer 17 describe an example of the resin layer, the other resin layer, and the other layer of the craze film according to the present embodiment, and are not limited thereto. ..

(Resin layer)
In the resin layer 12, crazes 14 extending in a certain direction are formed in stripes. In the present embodiment, a plurality of crazes 14 extending linearly or substantially linearly in the lateral direction (TD) of the resin layer 12 are formed, and the plurality of crazes 14 are formed parallel to or substantially parallel to each other. In this embodiment, a case where each craze is formed so as to extend in the lateral direction (TD) of the resin layer will be described. In the present embodiment, as long as the crazes are formed in stripes, the forming direction of each craze is not particularly limited, but it is preferable that each craze is formed so as to extend in the lateral direction (TD) of the resin layer. .. As a suitable method for forming each craze so as to extend in the lateral direction (TD) of the resin layer, as described above and later, the craze forming film 20 is pressed against the edge portion 54 of the processing blade 52. Therefore, a bent portion 24 is formed on the craze forming film 20, and the bent portion 24 is moved relative to the craze forming film 20. The processing using the processing blade is performed by adjusting the angle of the bent portion, the take-back stress, the shape of the edge portion of the processing blade, the moving speed, and the like so that _{the deflection light fraction Rr 30 is 15 to 65%.} Examples of the method of forming each craze so as to extend in the longitudinal direction (MD) of the resin layer include a chemical method (a method of immersing the craze forming film 20 in various solvents). In the above treatment using a chemical method, the type and concentration of the solvent and the additive contained in the film (addition for acting with the solvent to cause craze) so that _{the deflection light fraction Rr 30 is 15 to 65%.} Adjust the type and amount of agent).

The resin layer 12 preferably has a deflection light fraction Rr ₃₀ of 15 to 65%. The deflection light fraction Rr ₃₀ is more preferably 15 to 60%, further preferably 20 to 55%, particularly preferably 25 to 50%, and preferably 30 to 45%. Especially preferable.
Further, the resin layer 12 preferably has a deflection light fraction Rr _{50 of 5} to 55%. The deflection light fraction Rr ₅₀ is more preferably 10 to 50%, further preferably 20 to 48%, and particularly preferably 30 to 45%.

Deflecting light fraction _{Rr 30} of the resin layer 12, and the measurement method of deflecting the light fraction _{Rr 50} is deflected light fraction _{Rr 30} crazing films, and was discussed in the method for measuring the deflection light fraction _{Rr 50} The content is the same as the measurement method with the craze film except that the craze film is replaced with the resin layer 12. Therefore, the description here will be omitted.

When the deflection light fraction Rr ₃₀ is 15 to 65%, it is possible to increase the amount of light deflected for the incident light at _{an incident angle θ 1 = 30 °.} Further, when the deflected light fraction Rr ₅₀ is 5 to 55%, it is possible to increase the amount of light deflected for the incident light at _{an incident angle θ 1 = 50 °.}
Further, when the deflected light fraction Rr ₃₀ is 15 to 65% and the deflected light fraction Rr ₅₀ is 5 to 55%, the _{incident light at an incident angle θ 1} = about 30 ° and the incident light. It is possible to increase the amount of light deflected by the light incident at an incident angle θ _{1 = 50 °.}

In the resin layer 12, the width of each craze 14 (width in the direction perpendicular to the processing blade) is preferably 0.05 μm to 2 μm, more preferably 0.1 μm to 1.5 μm, and 0.15 μm. It is more preferably ~ 1 μm, even more preferably 0.6 μm to 1 μm, and particularly preferably 0.65 μm to 0.95 μm. When the width is 0.05 μm or more, it becomes easy to deflect the light. On the other hand, when the width is 2 μm or less, the transparency of the film is less likely to decrease, which is preferable. The width of the craze 14 means that 50% or more of the total number of crazes formed on the resin layer 12 is within the numerical range.
The length of each craze (the length in the direction parallel to the processing blade) is approximately the same as the length of the processing blade, but it may be the same as the length in the width direction of the craze film. It may be shorter than the length in the width direction. When the length of the craze is shorter than the length in the width direction of the craze film, it is easy to prevent the film from breaking during craze formation. The length of the craze is preferably 500 μm or more.

Mean values _{L R} interval _{L R} crazing 14 adjacent ', when the thickness of the resin layer and T, _{L R'} the value of / T, in a range of 0.20 to 0.80 It is preferably in the range of 0.25 to 0.60, more preferably in the range of 0.30 to 0.40.
The most preferred forms are within the scope thickness T of 20μm~60μm resin layer, the average value _{L R} 'distance _{L R} between adjacent craze is preferably in the range of 10 to 40 [mu] m, 13 It is more preferably in the range of ~ 30 μm, further preferably in the range of 15-19 μm.
A further most preferred embodiment is in the range thickness T of 35μm~50μm resin layer, the average value _{L R} 'distance _{L R} between adjacent craze is preferably in the range of 10 to 40 [mu] m, It is more preferably in the range of 13 to 30 μm, further preferably in the range of 15 to 19 μm.
If the average value of the distance L _R crazing 14 adjacent L _{R 'is} within the above range, it is possible to increase the more deflection light fraction.

In the resin layer 12, the number of crazes per 500 μm in length is preferably in the range of 15 to 45, more preferably in the range of 20 to 40, and in the range of 26 to 35. Is even more preferable. When the number of crazes per 500 μm in length is within the above range, the deflection light fraction can be further increased. The number of crazes per 500 μm in length is a value measured by the method described in Examples.

In the resin layer 12, the fine craze interval ratio is preferably in the range of 0 to 30%, more preferably in the range of 5 to 25%, and further preferably in the range of 10 to 18%. preferable. When the fine craze interval ratio is within the above range, the deflection light fraction can be further increased. The fine craze interval ratio is a value measured by the method described in Examples.

Due to the layer structure, the resin layer is not the outermost layer, and the width of each craze, the average value of the spacing between adjacent crazes, the number of crazes per 500 μm length, and the fine craze spacing ratio are measured from the film surface. If it is difficult, use an observation section preparation device such as an ultramicrotome to prepare a section for observing the cross section of the craze film in the direction perpendicular to the craze processing blade, and measure from the microscopic observation image. When observing with a microscope, the position where a straight line perpendicular to the craze is drawn (see the section on measuring the fine craze interval ratio in the examples described later) is located near the end of the resin layer on the side far from the craze processing blade. do.

In the resin layer 12, the craze depth D (μm) is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, based on the thickness of the resin layer. The depth of each craze formed on the resin layer 12 may be 100% with respect to the thickness of the resin layer. When the depth of each craze is in each of the above-mentioned preferable ranges, it becomes easy to deflect the light. The method for measuring the craze depth D is as described in the examples. As an example of the depth of each craze, the depth D (μm) of each craze is preferably 40 μm or more, more preferably 42.5 μm or more, and further preferably 45 μm or more.
The aspect ratio of each is formed on the resin layer 12 craze (i.e., _{L C} '/ D) is preferably from 0.05 to 0.55, more preferably from 0.10 to 0.41, 0.25 to 0 .40 is more preferable, and 0.30 to 0.37 is particularly preferable. When the aspect ratio of each craze is in each of the above-mentioned preferable ranges, it becomes easy to deflect the light.

The resin layer 12 contains a crystalline polystyrene-based resin. The crystalline polystyrene-based resin is heated from -40 ° C to 300 ° C at a rate of 10 ° C / min under nitrogen flow using DSC, held at 300 ° C for 5 minutes, and held at -40 ° C at 10 ° C / min. A polystyrene-based resin in which a clear melting peak appears on the DSC curve when the temperature is raised to 300 ° C. at 10 ° C./min after being cooled to -40 ° C. for 5 minutes. In the present invention, the content of the crystalline polystyrene-based resin contained in the resin layer 12 is preferably 50% by mass or more, more preferably 70% by mass or more of the resin component constituting the resin layer 12. , 80% by mass or more, further preferably 85% by mass or more, particularly preferably 90% by mass or more, and particularly preferably 95% by mass or more. Further, the content of the crystalline polystyrene-based resin contained in the resin layer 12 may be 100% by mass with respect to the entire resin component constituting the resin layer 12, or 100% by mass with respect to the entire resin layer. It may be.

As the crystalline polystyrene-based resin, it is preferable to mainly use a styrene-based resin having a syndiotactic structure. The syndiotactic structure is a syndiotactic structure in which the three-dimensional chemical structure is a three-dimensional structure in which phenyl groups and substituted phenyl groups, which are side chains of the main chain formed from carbon-carbon bonds, are alternately located in opposite directions. Refers to those having.

The tacticity (stereoregularity) of the crystalline polystyrene-based resin ^{can be quantified by the nuclear magnetic resonance method (13} C-NMR method) using isotope carbon. ^{13 The} tacticity measured by the C-NMR method can be indicated by the abundance ratio of a plurality of consecutive constituent units, for example, a diad for two, a triad for three, and a pentad for five. .. The crystalline polystyrene-based resin used in the present invention is usually 75% or more, preferably 85% or more, or 60% or more, preferably 75% or more, or 30% or more, preferably racemic pentad. Is a styrene-based polymer having a syndiotacticity of 50% or more.

The types of the crystalline polystyrene-based resin include polystyrene (styrene homopolymer), poly (alkylstyrene), poly (styrene halide), poly (alkylstyrene halide), poly (alkoxystyrene), and poly (vinyl benzoate). Acid esters), hydrides thereof and mixtures thereof, and copolymers containing these as main components.

Examples of the poly (alkyl styrene) include poly (methyl styrene), poly (ethyl styrene), poly (isopropyl styrene), poly (territory butyl styrene), poly (phenyl styrene), poly (vinyl naphthalene), and poly (vinyl). Styrene) and the like. Examples of the poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene) and the like. Examples of the poly (alkyl styrene halogenated) include poly (chloromethyl styrene). Examples of the poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

The comonomer component of the copolymer containing these structural units includes the above-mentioned styrene-based polymer monomer, an olefin monomer such as ethylene, propylene, butene, hexene, and octene, a diene monomer such as butadiene and isoprene, and a cyclic olefin monomer. , Cyclic diene monomer, methyl methacrylate, maleic anhydride, acrylonitrile and other polar vinyl monomers. Preferred styrene-based polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (p-terrific butylstyrene), poly (p-chlorostyrene), and poly (m-chlorostyrene). ), Poly (p-fluorostyrene), polystyrene hydride and copolymers containing these structural units.

As the crystalline polystyrene-based resin, a resin obtained by copolymerizing at least styrene and p-methylstyrene as a styrene-based monomer is preferable, and the content of p-methylstyrene in the styrene-based monomer is 1 to 30 mol%. It is preferably 3 to 15 mol%, and more preferably 3 to 15 mol%. Within the above range, it is preferable that the film can be easily formed with high thickness accuracy. By improving the thickness accuracy, it is easy to improve the variation accuracy of the deflection light fraction, which is preferable.

The molecular weight of the crystalline polystyrene-based resin is not particularly limited, but the weight average molecular weight is preferably 10,000 or more, more preferably 50,000 or more. By setting the weight average molecular weight to 10,000 or more, the thermal properties and mechanical strength of the obtained resin layer 22 can be improved. Further, the upper limit of the molecular weight of the polystyrene-based resin is preferably 3 million or less, more preferably 1.5 million or less, from the viewpoint of the thickness accuracy of the molded product.

The crystalline polystyrene-based resin conforms to JIS-K7210 and has a melt flow rate measured at 300 ° C. and 11.77 N, preferably 1 to 40 g / 10 minutes, more preferably 10 to 35 g / 10 minutes. By setting the melt flow rate in the above range, it is preferable that the film can be easily formed with high thickness accuracy.

As the crystalline polystyrene-based resin, one produced by a known method, for example, a method using styrene as a monomer and polymerizing using a metallocene catalyst, or a commercially available one may be used. Representative commercial products include, for example, XAREC (registered trademark) 142ZE, XAREC (registered trademark) 300ZC, XAREC (registered trademark) 130ZC and XAREC (registered trademark) 90ZC manufactured by Idemitsu Kosan Co., Ltd. These crystalline polystyrene-based resins may be used alone or in admixture of two or more.

In the resin layer 12, in addition to the crystalline polystyrene-based resin, a crystalline resin or an amorphous resin (hereinafter, also referred to as “another resin”) different from the crystalline polystyrene-based resin is used as a resin component. It may be contained within a range that does not impair the effects of the invention. Other resins can be appropriately selected for the purpose of adjusting low temperature impact resistance, adjusting surface roughness, adjusting various physical properties such as rigidity and strength, and the like.

The other resin is not particularly limited, and examples thereof include conventionally known resins suitable for forming the film-shaped resin layer 12. As a specific example of the other resin, a conventionally known resin suitable for film applications can be appropriately used. For example, polyolefin resins such as polyethylene, polypropylene, poly (1-butene), polyisobutene, poly (1-pentene), poly (4-methyl-1-pentene), cyclic polyolefin resins, or polymers thereof. Examples of resins include olefin polymers such as ethylene-propylene copolymers, propylene-butene copolymers, ethylene-butene copolymers, ethylene-norbornene copolymers, and ethylene-tetracyclododecene copolymers. can. In the case of a craze film having another resin layer or other layer, the olefin-based polymer is a modified olefin-based polymer such as acid-modified or alkali-modified from the viewpoint of adhesiveness to the other resin layer or the other layer. Is preferable.
As another specific example, an amorphous styrene resin is preferable because it has excellent miscibility with a crystalline polystyrene resin and easily forms a transparent resin layer. As styrene-based resins, amorphous, colorless and transparent general-purpose polystyrene (generally called GPPS, etc.) and impact-resistant polystyrene made by adding rubber to GPPS to give impact resistance (generally called HIPS, etc.). , Styrene / acrylonitrile copolymer resin obtained by copolymerizing styrene and acrylonitrile to have chemical resistance (generally called SAN etc.), acrylonitrile having both impact resistance due to rubber and chemical resistance due to acrylonitrile. Styrene-based thermoplastic elastomer (generally called TPS, etc.), which is a block copolymer of polystyrene as a hard segment and polyisoprene or polybutadiene as a soft segment, butadiene / styrene resin (generally called ABS, etc.) , Polystyrene-based thermoplastic elastomer, and the like can be preferably used. Commercially available products may be used as the styrene resin. Specifically, Septon (registered trademark) manufactured by Kuraray Co., Ltd., Lavalon (registered trademark) manufactured by Mitsubishi Resin Co., Ltd., Dick styrene (registered trademark) manufactured by DIC Corporation, and DIC Corporation Lurex (registered trademark) manufactured by the company, High Branch (registered trademark) manufactured by DIC Corporation, Sevian (registered trademark) manufactured by Daicel Polymer Co., Ltd. and the like can be preferably used.
Other specific examples include vinyl resins such as polyvinyl alcohol and polyvinyl acetal, polyester resins such as PET and PBT, polyurethane resins such as polycarbonate, polyamide resins such as nylon 66, and copolymer resins thereof. Be done.
Among them, the resin exemplified as the amorphous styrene resin is preferable because it is excellent in compatibility with the crystalline polystyrene resin and the transparency of the resin layer 12 is enhanced, so that the deflection light fraction can be easily increased.

The content of the other resin is preferably 20% by mass or less, more preferably 15% by mass or less, and 10% by mass or less with respect to the entire resin component constituting the resin layer 12. Is more preferable, and 5% by mass or less is particularly preferable. The other resins may be used alone or in combination of two or more.

If necessary, the resin layer 12 captures additives such as heat stabilizers, antioxidants, organic lubricants, inorganic lubricants, and chlorine as optional components within a range that does not significantly impair optical characteristics such as polarized light fraction. It may contain an agent, an antistatic agent, an ultraviolet absorber, a colorant and the like. The additive may be used alone or in combination of two or more.

Examples of the heat stabilizer and the antioxidant include phenol-based, hindered amine-based, phosphite-based, lactone-based, and tocopherol-based heat stabilizers and antioxidants. More specifically, dibutylhydroxytoluene, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (“Irganox® 1010” manufactured by BASF Japan Ltd.), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4hydroxy) benzene (“Irganox® 1330” manufactured by BASF Japan Ltd.), Tris (2, Examples thereof include 4-di-t-butylphenyl) phosphite (“Irgafos® 168” manufactured by BASF Japan Ltd.). Among these, at least one selected from phenol-based antioxidants or a combination thereof, or a combination of phenol-based and phosphite-based, and phenol-based and lactone-based, phenol-based and phosphite-based and lactone-based The combination is preferable from the viewpoint of imparting chemical stability of the film.

Examples of the organic lubricant include aliphatic amides such as stearic acid amides and erucic acid amides, lauric acid diethanolamides, alkyldiethanolamines, aliphatic monoglycerides, aliphatic diglycerides, silicone crosslinked polymers, and fluoropolymers. Examples of the inorganic lubricant include silica and alumina.

Examples of the chlorine trapping agent include calcium stearate, metal soaps, hydrotalcite and the like.

Examples of the antistatic agent include alkylmethyldibetaine, alkylamine diethanol and / or alkylamine ethanol ester and / or alkylamine diethanoldiester. Of these, two or more types of antistatic agents may be used in combination, and an aliphatic alcohol may be used in combination.
Among them, when stearyldiethanolamine monostearic acid ester and stearyldiethanolamine are used in combination, the antistatic performance is excellent.
Examples of typical commercially available antistatic agents include the Electro Stripper (registered trademark) series manufactured by Kao Corporation.

Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers and triazine-based ultraviolet absorbers. Commercially available products may be used as these, and for example, ADEKA STAB (registered trademark) manufactured by ADEKA Corporation can be preferably used.

The colorant is not particularly limited as long as it is usually used for a plastic film. Examples of the colorant include titanium oxide, calcium carbonate, satin white, cadmium / chromium-containing inorganic compounds, azo, and quinacridone organic pigments. Commercially available dyes and colored pigments may be used. For example, color master batch or dry color manufactured by Tokyo Ink Co., Ltd., Hi-Conc Master (registered trademark) manufactured by Dainichiseika Kogyo Co., Ltd., color compound, etc. should be preferably used. Can be done.

The resin layer 12 is unstretched. The resin layer 12 is not particularly limited as long as it is unstretched, but it is preferably formed by melt extrusion and then not stretched. Since the resin layer 12 is unstretched and has not undergone a stretching step, it is excellent in manufacturing efficiency in that the stretching step can be omitted. Moreover, since a stretching device is not required, the burden of introducing the device is small. Since the method for producing the resin layer 12 has been described in the section of the craze film, the description here will be omitted.

The thickness T of the resin layer 12 is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, further preferably 15 μm to 90 μm, particularly preferably 20 μm to 60 μm, and 35 μm to 35 μm. It is particularly preferably 50 μm. When the thickness of the resin layer 12 is 5 μm or more, breakage during craze treatment and breakage during use are less likely to occur, and the deflection light fraction is likely to be increased. On the other hand, when the thickness of the resin layer 12 is 200 μm or less, the deflection light fraction can be easily increased. In particular, when the incident angle is high, for example, even when the incident angle is 50 °, the deflection light fraction can be increased by setting the thickness.

The resin layer 12 preferably has a tensile elastic modulus in the flow direction (MD) of 1.7 GPa or more and 2.8 GPa or less, and more preferably 1.8 GPa or more and 2.7 GPa or less. When the tensile elastic modulus is 1.7 GPa or more, crazes are formed in the resin layer 12 (that is, the resin layer 22) before the craze treatment at a relatively narrow interval and depth so that the deflection light fraction becomes high. It becomes possible to do. Further, when the tensile elastic modulus is 2.8 GPa or less, it is possible to prevent the resin layer from breaking without forming crazes on the resin layer 12 before the craze treatment. The tensile elastic modulus is a value measured under the conditions described in the examples.

The resin layer 12 preferably has a breaking point elongation in the flow direction (MD) of 1% or more and 15% or less, more preferably 1.5% or more and 10% or less, and 2% or more and 4% or less. It is more preferable to have. When the breaking point elongation is 15% or less, the resin layer 12 before the craze treatment does not extend and craze can be appropriately formed. Further, when the elongation at the breaking point is 1% or more, it is possible to prevent the resin layer from breaking without forming crazes. The breaking point elongation is a value measured at 23 ° C. under the conditions described in Examples.

The breaking point stress in the flow direction (MD) of the resin layer 12 is preferably 18 MPa or more and 60 MPa or less, and more preferably 30 MPa or more and 50 MPa or less. When the breaking point stress is 18 MPa or more, it is possible to prevent the resin layer from breaking without forming crazes on the resin layer 12 before the craze treatment. Further, when the breaking point stress is 60 MPa or less, it is easy to appropriately form crazes on the resin layer 12, and it is easy to increase the deflection light fraction. The breaking point stress is a value measured at 23 ° C. under the conditions described in the examples.

The resin layer 12 has translucency, and specifically, the total light transmittance measured only with the resin layer 12 is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more. Is. The total light transmittance may be less than 100%, preferably 98% or less. Within the above range, it is easy to obtain a preferable polarized light fraction.

(Other resin layer)
In the other resin layer 15, crazes 16 extending in a certain direction are formed in stripes. The method of entering the craze 16 can be the same as described in the section of the resin layer 12. As shown in FIG. 2, the craze 16 may be continuously formed in the depth direction from the craze 14 of the resin layer 12, or may be formed in a portion where the craze 14 is not formed. .. It is preferable that the craze 16 is continuously formed in the depth direction from the craze 14 of the resin layer 12, because it is easy to increase the deflection light fraction.

The deflection light fraction Rr _{30 of the} other resin layer 15 is preferably 15 to 65%, more preferably 15 to 60%. Further, the other resin layer 15 preferably has a deflection light fraction Rr _{50 of 5} to 55%. The method for measuring the deflected light fraction Rr ₃₀ and the deflected light fraction Rr ₅₀ of the other resin layer 15 is described in the section of the method for measuring the deflected light fraction Rr ₃₀ and the deflected light fraction Rr _{50 of the craze film.} In the contents described, the method is the same as the method for measuring the craze film, except that the craze film is replaced with another resin layer 15. Therefore, the description here will be omitted.

In the other resin layer 15, the width of each craze 16 (width in the direction perpendicular to the processing blade) is preferably formed continuously from the craze 14 of the resin layer 12 in the depth direction. It is preferable that they are the same. Specifically, it is preferably 0.05 μm to 2 μm, more preferably 0.1 μm to 1.5 μm, further preferably 0.15 μm to 1 μm, and even more preferably 0.6 μm to 1 μm. , 0.65 μm to 0.95 μm is particularly preferable. When the width is 0.05 μm or more, it becomes easy to deflect the light. On the other hand, when the width is 2 μm or less, the transparency of the film is less likely to decrease, which is preferable. The width of the craze 16 means that 50% or more of the total number of crazes formed on the other resin layer 15 is within the numerical range.
The length of each craze (the length in the direction parallel to the processing blade) is preferably the same as that of the resin layer 12 because it is preferably formed continuously from the craze 14 of the resin layer 12 in the depth direction. ..

In the other resin layer 15, the average value of the intervals between the adjacent crazes 16 is preferably the same as that of the resin layer 12 because it is preferably formed continuously from the crazes 14 of the resin layer 12 in the depth direction. preferable. Specifically, it is preferably in the range of 10 to 40 μm, more preferably in the range of 13 to 30 μm, and further preferably in the range of 15 to 19 μm. When the average value of the intervals between the adjacent crazes 16 is within the above range, the deflection light fraction can be further increased.

In the other resin layer 15, the number of crazes per 500 μm in length is preferably the same as that of the resin layer 12 because it is preferably formed continuously from the crazes 14 of the resin layer 12 in the depth direction. Specifically, it is preferably in the range of 15 to 45, more preferably in the range of 20 to 40, and even more preferably in the range of 26 to 35. When the number of crazes per 500 μm in length is within the above range, the deflection light fraction can be further increased.

In the other resin layer 15, the fine craze interval ratio is preferably in the range of 0 to 30%, more preferably in the range of 5 to 25%, and in the range of 10 to 18%. Is even more preferable. When the fine craze interval ratio is within the above range, the deflection light fraction can be further increased.

Due to the layer structure, the other resin layer is not the outermost layer, and the width of each craze, the average value of the spacing between adjacent crazes, the number of crazes per 500 μm length, and the fine craze spacing ratio are measured from the film surface. If it is difficult to measure, use an observation section preparation device such as an ultramicrotome to prepare a section for observing the cross section of the craze film in the direction perpendicular to the craze processing blade, and measure from the microscopic observation image. When observing with a microscope, the position where a straight line orthogonal to the craze is drawn is near the end of the other resin layer on the side far from the craze processing blade.

The craze depth (μm) in the other resin layer 15 is preferably 50% or more, more preferably 60% or more, and more preferably 90%, with respect to the thickness of the other resin layer 15 from the viewpoint of facilitating light deflection. The above is more preferable. The depth of each craze formed on the other resin layer 15 may be 100% with respect to the thickness of the other resin layer 15. The depth of the craze in the other resin layer 15 is preferably less than 50%, more preferably 40% or less, and more preferably 30% or less with respect to the thickness of the other resin layer 15 from the viewpoint of suppressing fracture. .. The method for measuring the craze depth is the method described in the examples.

The other resin layer 15 is a layer that does not correspond to a resin layer (a layer containing a crystalline polystyrene-based resin and is unstretched), and if it is a layer capable of forming a craze, its constituent material is particularly Not limited. For example, as the main component of the other resin layer 15 (50% by mass or more of the resin component constituting the other resin layer), among those described in the section of "other resins" of the resin layer 12, polyolefin-based resins and the like , Cyclic polyolefin-based resins, or copolymer resins thereof. Of these, a cyclic polyolefin resin or a copolymer resin thereof is preferable from the viewpoint of easily forming continuous crazes from the resin layer 12. Specific examples thereof include olefin polymers such as ethylene-norbornene copolymers and ethylene-tetracyclododecene copolymers. Commercially available resins may be used for these, and typical commercially available products include, for example, TOPAS (registered trademark) 6015S-04, 6017S-04 manufactured by Polyplastics Co., Ltd., Apel (registered trademark) APL6015T manufactured by Mitsui Chemicals, Inc., etc. Can be mentioned.

If necessary, the other resin layer 15 is an additive similar to that described in the section of the resin layer 12, for example, a heat stabilizer, as an optional component within a range that does not significantly impair the optical characteristics such as the deflection light fraction. , Antioxidants, organic lubricants, inorganic lubricants, chlorine trapping agents, antistatic agents, colorants and the like may be contained.

The other resin layer 15 may be a craze-formed layer, and may be unstretched or stretched. Since the method for producing the other resin layer 15 has been described in the section of the craze film, the description here will be omitted.

The thickness of the other resin layer 15 is preferably 5 μm to 150 μm, more preferably 10 μm to 100 μm, further preferably 15 μm to 60 μm, and particularly preferably 20 μm to 40 μm. When the thickness of the other resin layer 15 is within the above range, it is preferable that crazes are continuously formed from the craze 14 of the resin layer 12 in the depth direction.

The tensile elastic modulus in the flow direction (MD) of the other resin layer 15 is preferably 1.4 GPa or more and 2.8 GPa or less, and more preferably 1.5 GPa or more and 2.7 GPa or less. When the tensile elastic modulus is 1.4 GPa or more, it is possible to form crazes on the other resin layer 15 before the craze treatment at a relatively narrow interval and depth so that the deflection light fraction becomes high. Become. Further, when the tensile elastic modulus is 2.8 GPa or less, it is possible to prevent the resin layer from breaking without forming crazes on the other resin layer 15 before the craze treatment.

The other resin layer 15 preferably has a breaking point elongation in the flow direction (MD) of 0.5% or more and 45% or less, more preferably 1% or more and 30% or less, and 2% or more and 20%. The following is more preferable. When the breaking point elongation is 45% or less, the other resin layer 15 before the craze treatment does not extend and the craze can be appropriately formed. Further, when the breaking point elongation is 0.5% or more, it is possible to prevent the resin layer from breaking without forming crazes.

The breaking point stress in the flow direction (MD) of the other resin layer 15 is preferably 18 MPa or more and 60 MPa or less, and more preferably 30 MPa or more and 55 MPa or less. When the breaking point stress is 18 MPa or more, it is possible to prevent the resin layer from breaking without forming crazes on the other resin layer 15 before the craze treatment. Further, when the breaking point stress is 60 MPa or less, it is easy to appropriately form crazes on the resin layer 12, and it is easy to increase the deflection light fraction.

The other resin layer 15 preferably has translucency, and specifically, the total light transmittance measured only by the other resin layer 15 is preferably 80% or more, more preferably 85% or more. , More preferably 90% or more. The total light transmittance may be less than 100%, preferably 98% or less. Within the above range, it is easy to obtain a preferable polarized light fraction.

(Other layers)
No craze is formed on the other layer 17.

As long as the other layer 17 is a layer that is not craze-formed, its constituent material is not particularly limited. For example, examples of the main component of the other layer 17 include those described in the section “Other resins” of the resin layer 12. Among them, the amorphous styrene resin is preferable because it has excellent adhesiveness to the resin layer.

The other layers 17 have the same additives as those described in the section of the resin layer 12 as optional components, for example, a heat stabilizer, as long as the optical characteristics such as the deflection light fraction are not significantly impaired. It may contain an antioxidant, an organic lubricant, an inorganic lubricant, a chlorine trapping agent, an antistatic agent, an ultraviolet absorber, a colorant and the like.

The other layer 17 may be a layer that is not craze-formed and may be unstretched or stretched. Since the method for producing the other layer 17 has been described in the section of the craze film, the description here will be omitted.

The thickness of the other layer 17 is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, further preferably 20 μm to 120 μm, and particularly preferably 30 μm to 100 μm. When the thickness of the other layer 17 is 5 μm or more, breakage during the craze treatment and breakage during use are less likely to occur. On the other hand, when the thickness of the other layer 17 is 200 μm or less, the deflection light fraction can be easily increased.

The tensile elastic modulus in the flow direction (MD) of the other layer 17 is preferably 0.2 GPa or more and 2.4 GPa or less, and more preferably 0.3 GPa or more and 1.8 GPa or less. When the tensile elastic modulus is 0.2 GPa or more, scratches and the like are less likely to occur during the craze treatment, which is preferable. Further, when the tensile elastic modulus is 2.4 GPa or less, it is possible to prevent the craze film from breaking during the craze treatment.

The other layer 17 preferably has a breaking point elongation of 1% or more and 1100% or less in the flow direction (MD), more preferably 10% or more and 900% or less, and 50% or more and 600% or less. Is even more preferable. When the elongation at the breaking point is 1100% or less, scratches and the like are less likely to occur during the craze treatment, which is preferable. Further, when the breaking point elongation is 1% or more, it is possible to prevent the craze film from breaking during the craze treatment.

The breaking point stress in the flow direction (MD) of the other layer 17 is preferably 18 MPa or more, more preferably 28 MPa or more. When the breaking point stress is 18 MPa or more, it is possible to prevent the craze film from breaking during the craze treatment. Further, although the upper limit of the breaking point stress is not obtained, it is about 60 MPa or less.

The other layer 17 preferably has translucency, and specifically, the total light transmittance measured only by the other layer 17 is preferably 80% or more, more preferably 85% or more, and further. It is preferably 90% or more. The total light transmittance may be less than 100%, preferably 98% or less. Within the above range, it is easy to obtain a preferable polarized light fraction.

The use of the craze film is not particularly limited, but since it has a function of increasing the amount of deflected light, it can be suitably used as, for example, a daylighting film or a film for a display board. The daylighting film is a film for brightening the room by deflecting external light (light entering from the outside, for example, sunlight) as incident light toward the ceiling. The display board film is a film for improving visibility by reflecting the light of ceiling lighting upward when a display board such as a price tag at a low position is viewed from a high position. For example, by arranging a reflector, a display plate (for example, a transparent substrate on which numbers or the like are printed), and a craze film in this order, it is possible to improve the visibility of the numbers or the like on the display plate. can.

FIG. 4 is a schematic view for explaining how the craze film is used as a daylighting film. As shown in FIG. 4, a window glass 44 is provided on the wall 42 of the building. In FIG. 4, the left side is outdoors and the right side is indoors. The craze film 10 is provided on the indoor side of the window glass 44. As a method of fixing the craze film 10 on the window glass 44, for example, a method of fixing the outer peripheral portion of the craze film 10 to the outer peripheral portion or the wall 42 of the window glass 44 using a fixing member (not shown), or a transparent portion. Examples thereof include a method of attaching a part (for example, an outer peripheral portion) or the whole of the craze film 10 to the window glass 44 or the wall 42 by using a light adhesive or an adhesive.

When sunlight 46 is incident on the window glass 44 provided with the craze film 10, the craze film 10 deflects at least a part of the sunlight 46 toward the ceiling indoors. As a result, the room can be brightened. Here, the craze film 10 has a deflection light fraction Rr ₃₀ of 15 to 65%. Since the deflection light fraction Rr ₃₀ of the craze film 10 is 15 to 65%, light having an incident angle of about 30 ° can be efficiently deflected toward the ceiling.
Further, when the deflection light fraction Rr _{50 of} the craze film 10 is 5 to 55%, the light having an incident angle of about 50 ° can be efficiently deflected toward the ceiling. That is, when the deflection light fraction Rr _{30 of} the craze film 10 is 15 to 65% and the deflection light fraction Rr ₅₀ is 5 to 55%, when the sun is in a high position (for example, summer or daytime). ) And when the sun is low (eg, winter or evening), that is, regardless of the season or time, the sunlight can be efficiently deflected toward the ceiling.

Note that FIG. 4 shows that the sunlight 46 is reflected once by the craze 14, but the present invention is not limited to this example, and odd-numbered reflections such as three-fold reflection and five-fold reflection may be used. FIG. 5 is another schematic view for explaining how the craze film is used as a daylighting film. FIG. 5 shows how the sunlight 46 is reflected three times by the craze 14.

As applications other than the above, the craze film 10 can be used as various optical films such as a field-selective film that transmits only light from a certain direction and reflects light from another direction.

(Film for forming craze)
The craze-forming film according to the present embodiment is a film before craze is formed in the above-mentioned craze film. Therefore, in the following, the parts different from the craze film will be mainly described, and the explanations common to the craze film will be simplified.

FIG. 6 is a perspective view schematically showing a film for forming a craze according to an embodiment. FIG. 7 is a perspective view schematically showing a film for forming a craze according to another embodiment. The craze-forming film 20 is made of a resin layer 22. The craze forming film 21 includes a resin layer 22, another resin layer 25, and other layers 27 in this order.
In the present specification, the craze-forming film 20 corresponds to the craze film 10 before the craze treatment is performed, and the craze-forming film 21 corresponds to the craze film 11 before the craze treatment is performed. Further, the resin layer 22 corresponds to the resin layer 12 before the craze treatment is performed, the other resin layer 25 corresponds to the other resin layer 15 before the craze treatment is performed, and the other layer 27 corresponds to the other resin layer 15 before the craze treatment is performed. Corresponds to the other layer 17 before the craze treatment is performed.
Hereinafter, the craze forming film 20 composed of the resin layer 22 and the craze forming film 21 including the resin layer 22, the other resin layer 25, and the other layer 27 in this order will be described. The forming film may have a resin layer, and the layer structure may be the same as that described in the section of the craze film.

As described above, the craze-forming film is a film before the craze treatment in the craze film. Since the method for producing a craze-forming film is the one before the craze treatment in the content described in the section of the craze film, the description thereof is omitted here.

The thickness of the craze forming film can be the same as that of the craze film.

The craze forming film preferably has a tensile elastic modulus in the flow direction (MD) of 2.0 GPa or more and 3.2 GPa or less, more preferably 2.05 GPa or more and 3.1 GPa or less, and 2.1 GPa or more 3 It is more preferably 0.0 GPa or less. When the tensile elastic modulus is 2.0 GPa or more, it is possible to form crazes at a relatively narrow interval and depth such that the amount of deflected light increases. Further, when the tensile elastic modulus is 3.2 GPa or less, it is possible to prevent the film from breaking without forming crazes. The tensile elastic modulus is a value measured under the conditions described in the examples.
The tensile elastic modulus in the flow direction (MD) of the craze-forming film (that is, the craze film) after the craze treatment tends to be about 10 to 20% lower than the tensile elastic modulus before the craze treatment. As described in the section, the tensile elastic modulus of the craze film is preferably 1.7 GPa or more and 2.8 GPa or less, and more preferably 1.8 GPa or more and 2.7 GPa or less.

The craze forming film preferably has a breaking point elongation in the flow direction (MD) of 0.2% or more and 30% or less, more preferably 1% or more and 15% or less, and 1.2% or more and 5%. It is more preferably% or less, and particularly preferably 1.5% or more and 3% or less. When the breaking point elongation is 30% or less, the craze-forming film does not stretch and the craze can be formed appropriately. Further, when the breaking point elongation is 0.2% or more, it is possible to prevent the film from breaking without forming crazes. The breaking point elongation is a value measured at 23 ° C. under the conditions described in Examples.
The breaking point elongation of the craze forming film (that is, the craze film) after the craze treatment tends to be about 50% higher than the breaking point elongation before the craze treatment, which is explained in the section of the craze film. As described above, the breaking point elongation of the craze film is preferably 1% or more and 15% or less, more preferably 1.5% or more and 10% or less, and preferably 2% or more and 4% or less. More preferred.

The break point stress in the flow direction (MD) of the craze forming film is preferably 20 MPa or more and 60 MPa or less, more preferably 30 MPa or more and 55 MPa or less, and further preferably 37 MPa or more and 50 MPa or less. When the breaking point stress is 20 MPa or more, it is possible to prevent the craze-forming film from breaking without forming crazes. Further, when the breaking point stress is 60 MPa or less, it is easy to form crazes on the film appropriately and it is easy to increase the deflection light fraction. The breaking point stress is a value measured at 23 ° C. under the conditions described in the examples.
The breaking point stress of the craze forming film (that is, the craze film) after the craze treatment tends to be about 10% lower than the breaking point elongation before the craze treatment, which was explained in the section of the craze film. As described above, the breaking point stress of the craze film is preferably 18 MPa or more and 60 MPa or less, and more preferably 30 MPa or more and 50 MPa or less.

(Resin layer)
The resin layer 22 contains a crystalline polystyrene-based resin. Examples of the crystalline polystyrene-based resin include those similar to those described in the section of the resin layer 12.

The resin layer 22 is unstretched. The resin layer 22 is not particularly limited as long as it is unstretched. As described above, examples of the resin layer 22 include those formed by the method described in the section of the craze film as “when the craze film is composed of only the resin layer”.

The thickness of the resin layer 22 can be the same as that of the resin layer 12.

The resin layer 22 has a tensile elastic modulus in the flow direction (MD) of 2.0 GPa or more and 3.2 GPa or less, preferably 2.05 GPa or more and 3.1 GPa or less, and 2.1 GPa or more and 3.0 GPa or less. Is more preferable. Since the tensile elastic modulus is 2.0 GPa or more, it is possible to form crazes at a relatively narrow interval and depth such that the amount of deflected light increases. Further, since the tensile elastic modulus is 3.2 GPa or less, it is possible to prevent the resin layer 22 from breaking without forming crazes. The tensile elastic modulus is a value measured under the conditions described in the examples.
The tensile elastic modulus in the flow direction (MD) of the resin layer 22 (that is, the resin layer 12) after the craze treatment tends to be about 10 to 20% lower than the tensile elastic modulus before the craze treatment, and the resin layer. As described in the section 12, the tensile elastic modulus of the resin layer 12 is preferably 1.7 GPa or more and 2.8 GPa or less, and more preferably 1.8 GPa or more and 2.7 GPa or less.

The resin layer 22 has a breaking point elongation in the flow direction (MD) of 0.2% or more and 30% or less, preferably 1% or more and 15% or less, and 1.2% or more and 5% or less. Is more preferable, and 1.5% or more and 3% or less is further preferable. Since the elongation at the breaking point is 30% or less, the resin layer 22 does not extend and the craze can be appropriately formed. Further, since the elongation at the breaking point is 0.2% or more, it is possible to prevent the resin layer 22 from breaking without forming a craze. The breaking point elongation is a value measured at 23 ° C. under the conditions described in Examples.
The elongation at the breaking point of the resin layer 22 (that is, the resin layer 12) after the craze treatment tends to be about 50% higher than the elongation at the breaking point before the craze treatment. As described above, the elongation at break of the resin layer 12 is preferably 1% or more and 15% or less, more preferably 1.5% or more and 10% or less, and 2% or more and 4% or less. Is more preferable.

The breaking point stress in the flow direction (MD) of the resin layer 22 is preferably 20 MPa or more and 60 MPa or less, more preferably 30 MPa or more and 55 MPa or less, and further preferably 37 MPa or more and 50 MPa or less. When the breaking point stress is 20 MPa or more, it is possible to prevent the resin layer 22 from breaking without forming crazes. Further, when the breaking point stress is 60 MPa or less, it is easy to form crazes on the film appropriately and it is easy to increase the deflection light fraction. The breaking point stress is a value measured at 23 ° C. under the conditions described in the examples.
The breaking point stress of the resin layer 22 (that is, the resin layer 12) after the craze treatment tends to be about 10% lower than the breaking point elongation before the craze treatment, which will be described in the section of the resin layer 12. As described above, the breaking point stress of the resin layer 12 is preferably 18 MPa or more and 60 MPa or less, and more preferably 30 MPa or more and 50 MPa or less.

(Other resin layer)
Examples of the constituent material of the other resin layer 25 include the same materials as those described in the section of the other resin layer 15.

The thickness of the other resin layer 25 can be the same as that of the other resin layer 15.

The tensile elastic modulus in the flow direction (MD) of the other resin layer 25 is preferably 1.5 GPa or more and 3.2 GPa or less, more preferably 1.6 GPa or more and 3.1 GPa or less, and 1.7 GPa or more. It is more preferably 3.0 GPa or less. When the tensile elastic modulus is 1.5 GPa or more, it is possible to form crazes at a relatively narrow interval and depth such that the deflection light fraction becomes high. Further, when the tensile elastic modulus is 3.2 GPa or less, it is possible to prevent the other resin layer 25 from breaking without forming the craze.
The tensile elastic modulus in the flow direction (MD) of the other resin layer 25 (that is, the other resin layer 15) after the craze treatment tends to be about 10 to 20% lower than the tensile elastic modulus before the craze treatment. As described in the section of the other resin layer 15, the tensile elastic modulus of the other resin layer 15 is preferably 1.4 GPa or more and 2.8 GPa or less, and 1.5 GPa or more and 2.7 GPa or less. Is more preferable.

The other resin layer 25 preferably has a breaking point elongation in the flow direction (MD) of 0.2% or more and 30% or less, more preferably 1% or more and 20% or less, and 1.2% or more. It is more preferably 15% or less, and particularly preferably 1.5% or more and 10% or less. When the breaking point elongation is 30% or less, the other resin layer 25 does not extend and the craze can be appropriately formed. Further, when the breaking point elongation is 0.2% or more, it is possible to prevent the other resin layer 25 from breaking without forming the craze.
The elongation at the breaking point of the other resin layer 25 (that is, the other resin layer 15) after the craze treatment tends to be about 50% higher than the elongation at the breaking point before the craze treatment. As described in the section of the resin layer 15, the elongation at break point of the other resin layer 15 is preferably 0.5% or more and 45% or less, and more preferably 1% or more and 30% or less. More preferably, it is 2% or more and 20% or less.

The breaking point stress in the flow direction (MD) of the other resin layer 25 is preferably 20 MPa or more and 60 MPa or less, more preferably 30 MPa or more and 55 MPa or less, and further preferably 37 MPa or more and 50 MPa or less. When the breaking point stress is 20 MPa or more, it is possible to prevent the other resin layer 25 from breaking without forming crazes. Further, when the breaking point stress is 60 MPa or less, it is easy to form crazes appropriately on the resin layer 25 and it is easy to increase the deflection light fraction.
The breaking point stress of the other resin layer 25 (that is, the other resin layer 15) after the craze treatment tends to be about 10% lower than the breaking point elongation before the craze treatment, and the other resin. As described in the section of layer 15, the breaking point stress of the other resin layer 15 is preferably 18 MPa or more and 60 MPa or less, and more preferably 30 MPa or more and 55 MPa or less.

(Other layers)
Examples of the constituent materials of the other layer 27 include the same materials as those described in that section.

The thickness of the other layer 27 can be the same as that of the other layer 17.

The tensile elastic modulus in the flow direction (MD) of the other layer 27 is preferably 0.2 GPa or more and 2.5 GPa or less, more preferably 0.4 GPa or more and 2.0 GPa or less, and 0.5 GPa or more 1 It is more preferably 8.8 GPa or less. When the tensile elastic modulus is 0.2 GPa or more, scratches and the like are less likely to occur during the craze treatment, which is preferable. Further, when the tensile elastic modulus is 2.5 GPa or less, it is possible to prevent the craze film from breaking during the craze treatment.
The tensile elastic modulus in the flow direction (MD) of the other layer 27 (that is, the other layer 17) after the craze-forming film is creased is about 10 to 20% of the tensile elastic modulus before the craze treatment. The tensile elastic modulus of the other layer 17 is preferably 0.2 GPa or more and 2.4 GPa or less, and 0.3 GPa or more and 1.8 GPa or more, as described in the section of the other layer 17. The following is more preferable.

The other layer 27 preferably has a breaking point elongation of 1% or more and 1000% or less in the flow direction (MD), more preferably 10% or more and 800% or less, and 50% or more and 500% or less. Is even more preferable. When the elongation at the breaking point is 1000% or less, scratches and the like are less likely to occur during the craze treatment, which is preferable. Further, when the breaking point elongation is 1% or more, it is possible to prevent the craze film from breaking during the craze treatment.
The fracture point elongation of the other layer 27 (that is, the other layer 17) after the craze-forming film is creased tends to be about 50% higher than the fracture point elongation before the craze treatment. Yes, as described in the section of the other layer 17, the elongation at break point of the other layer 17 is preferably 1% or more and 1100% or less, and more preferably 10% or more and 900% or less. More preferably, it is 50% or more and 600% or less.

The breaking point stress in the flow direction (MD) of the other layer 27 is preferably 20 MPa or more, more preferably 30 MPa or more. When the breaking point stress is 20 MPa or more, it is possible to prevent the craze film from breaking during the craze treatment. Further, although the upper limit of the breaking point stress is not obtained, it is about 60 MPa or less.
The breaking point stress of the other layer 27 (that is, the other layer 17) after the craze treatment tends to be about 10% lower than the breaking point elongation before the craze treatment, and the breaking point stress of the other layer 17 tends to be about 10% lower. As described in the section, the breaking point stress of the other layer 17 is preferably 18 MPa or more, more preferably 28 MPa or more and 60 MPa or less.

The film for forming a craze composed of only the resin layer 22 contains a crystalline polystyrene resin, is unstretched, and has a tensile elastic modulus in the flow direction (MD) of 2.0 GPa or more and 3.2 GPa or less. , A commercially available product having a structure in which the elongation at break in the flow direction (MD) is 0.2% or more and 30% or less can be used. Examples of such a craze forming film include "SPS film" manufactured by Goyo Paper Works Co., Ltd.

(Manufacturing method of craze film)
FIG. 8 is a perspective view for explaining a method for manufacturing a craze film according to an embodiment, and FIG. 9 is a side view thereof.
The method for producing a craze film according to an embodiment is as follows.
Step A to prepare the film 20 for forming a craze,
The craze forming film 20 is pressed against the edge portion 54 of the processing blade 52 to form a bent portion 24 on the craze forming film 20, and the bent portion 24 is moved relative to the craze forming film 20. The resin layer 22 has a step B of forming the craze 14 in a striped pattern. According to this method for producing a craze film, the craze film of the present embodiment can be suitably produced. However, the method for producing the craze film of the present embodiment is not limited to the above and the following production methods.

In this embodiment, a case where a craze film is produced by using the craze forming apparatus shown in FIGS. 8 and 9 will be described.

The craze forming apparatus 50 includes at least a processing blade 52 having an edge portion 54 at one end, a guide roller 56, and a tension applying mechanism (not shown).

In the method for producing a craze film according to the present embodiment, first, a craze forming film 20 is prepared (step A).

Next, the craze forming film 20 is held in a tense state by the guide roller 56 and the tension applying mechanism, and the craze forming film 20 is pressed against the edge portion 54 of the processing blade 52 to locally press the craze forming film 20. The bent portion 24 is formed by bending the film. Next, the craze forming film 20 is conveyed via the guide roller 56 and the like, and the bent portion 24 is gradually moved with respect to the craze forming film 20 to form the craze 14 in a striped shape on the resin layer 22 ( Step B).

_{At this time, the angle θ 2} formed by the craze-forming film 20 at the bent portion 24 is preferably 15 ° to 160 °, more preferably 40 ° to 120 °, and 50 ° to 100 °. Is even more preferable. The larger the angle θ ₂ , the smaller the deflection light fraction Rr ₃₀ and the deflection light fraction Rr ₅₀ tend to be.
Further, it is preferable that the tip shape of the edge portion 54 is hemispherical with a radius of 1.2 mm or less (more preferably, a radius of 1 mm or less) because it is easy to form a craze capable of increasing the deflection light fraction. On the other hand, a hemispherical shape having a radius of 0.1 mm or more is preferable from the viewpoint that the quality such as the deflection light fraction is unlikely to change during continuous production and the film is less likely to be scratched during the craze treatment. The reason for this is that if the hemisphere has a radius of 0.1 mm or more, the shape change due to wear is unlikely to occur even if the craze forming process is continuously performed, so that the quality such as the deflection light fraction is continuous. It is estimated that it is unlikely to change during production. The tip shape of the edge portion 54 is more preferably a hemisphere having a radius of 0.2 mm or more and 0.8 mm or less, and particularly preferably a hemisphere having a radius of 0.3 mm or more and 0.7 mm or less. The larger the radius of the tip of the edge portion 54 _{, the smaller the deflection light fraction Rr 30} and the deflection light fraction Rr ₅₀ tend to be.
_{When the angle θ 2} formed by the craze-forming film 20 in the bent portion 24 is 15 ° to 160 ° and the tip shape of the edge portion 54 is a hemisphere having a radius of 1 mm or less, the craze can be formed more preferably. can.

The moving speed (conveying speed) for forming the craze 14 in stripes on the craze forming film 20 using the craze forming apparatus 50 is not limited, but is 150,000 mm / min from the viewpoint of resistance to scratches during the craze processing. It is preferably 1 mm / min or more from the viewpoint of production efficiency. The moving speed is more preferably 100,000 mm / min to 5 mm / min, further preferably 20000 mm / min to 10 mm / min, and particularly preferably 10000 mm / min to 10 mm / min. The larger the moving speed, the larger the deflected light fraction Rr ₃₀ and the deflected light fraction Rr ₅₀ tend to be.

The width of the crazes 14 formed on the craze forming film 20, the distance between the crazes 14 and the like are the temperature and speed at which the crazes 14 are formed, the take-back stress of the craze forming film 20, and the edge portion 54 of the processing blade 52. It can be adjusted by the tip shape, the bending angle θ _{2 of the film, and the like.}

Here, since the take-back stress applied to the craze forming film 20 tends to form a craze capable of increasing the deflection light fraction, the breaking point stress of the craze forming film in the direction orthogonal to the craze processing blade ( For example, when the craze processing blade is applied in a direction orthogonal to the flow direction of the film, the stress at the breaking point in the flow direction of the film) is preferably 15% or more and 85% or less, more preferably 20% or more and 80% or less. , 25% or more and 75% or less is more preferable, and 30% or more and 70% or less is particularly preferable. When the craze-forming film of the present embodiment is used, suitable crazes are easily formed without applying a high stress close to the breaking point stress, and problems such as breaking during the craze treatment are unlikely to occur. The larger the take-up stress, the larger the deflection light fraction Rr ₃₀ tends to be.
Further, it is preferable that the angle θ ₂ and the take-back stress are as shown in (a) or (b) below.
(A) Increase the angle θ ₂ and increase the take-up stress.
(B) The angle θ ₂ is reduced and the take-up stress is reduced.
As a preferable combination of the above (a), the angle θ ₂ is 75 to 160 °, and the take-up stress is within the range of 40 to 85% of the breaking point stress, and more preferably the angle θ ₂ is 80 to 120. ° And the take-up stress is in the range of 45 to 75% of the breaking point stress.
As a preferable combination of the above (b), the angle θ ₂ is 20 to 75 °, and the take-up stress is within the range of 15 to 70% of the breaking point stress, and more preferably the angle θ ₂ is 40 to 70. ° And the take-up stress is in the range of 25 to 50% of the above-mentioned breaking point stress.
By setting the angle θ ₂ and the tension as described above, a craze capable of increasing the deflection light fraction can be suitably formed. Of these, the above (a) is preferable from the viewpoint of preventing breakage during the craze treatment.

In the above-described embodiment, the case where the craze 14 is formed in a striped shape on the resin layer 22 by fixing the positions of the processing blade 52, the guide roller 56, and the like and transporting the craze forming film 20 will be described. However, the present invention is not limited to this example. For example, the craze forming film 20 may be fixed and the processing blade 52 or the like may be moved to form the craze in a striped shape on the resin layer. That is, in the present invention, the craze may be formed in stripes on the resin layer by moving the bent portion relative to the film for forming the craze.

Since the atmospheric temperature of the craze forming film and the processing blade during the craze treatment affects the interval, length, width, depth and the like of the crazes to be formed, it is preferable to keep the temperature constant at a predetermined temperature. The predetermined temperature is preferably 5 ° C to 50 ° C, more preferably 15 ° C to 40 ° C. Since the processing blade tends to gradually raise the temperature due to frictional heat in continuous processing, it is preferable to provide a temperature control mechanism for controlling the temperature of the processing blade.

After forming the craze (after step B), a step of allowing the additive to be present in the craze of the craze film may be performed, if necessary. As a method of allowing the additive to be present in the craze of the craze film, a method of immersing the additive in a dispersion liquid or a solution containing the additive (hereinafter, also simply referred to as a containing liquid) or a method of applying the additive-containing liquid is used. It can be exemplified. As the solvent of the additive-containing liquid, water, an organic solvent and the like can be used. Immersion in the additive-containing liquid can be performed, for example, at the same time as the craze treatment or after the craze treatment. In addition, after dipping or coating, a process of removing excess additive-containing liquid (for example, cleaning) or a process for fixing the additive to the film (for example, heating or irradiation treatment with ultraviolet rays or electron beams). May have a step of performing.

In the above-described embodiment, the case where the craze-forming film 20 made of the resin layer 22 is subjected to the craze treatment has been described, but the layer structure of the craze-forming film to be the target of the craze treatment is not limited to this. For example, the craze-forming film 21 may be creased. Each condition of the craze treatment can be appropriately set within the range described above according to the layer structure.

The craze film according to the present embodiment can be used as a daylighting device of the present embodiment by arranging it on a member. The member may be any member having light transmittance. The shape of the member is preferably a substrate shape. Examples of the components constituting the member include glass (quartz glass, soda glass, etc.); a light-transmitting resin such as polycarbonate and acrylic resin; and the like. The member made of glass includes not only float glass but also tempered glass and frosted glass.
In the daylighting apparatus of the present embodiment, an adhesive layer and / or an adhesive layer may be provided between the craze film and the member. When an adhesive layer and / or an adhesive layer is provided between the craze film and the member, the craze film and the member can be bonded together. Examples of the components constituting the adhesive layer and / or the adhesive layer include acrylic resins, urethane resins, silicone resins and the like. On the other hand, when the adhesive layer and / or the adhesive layer is not used, the craze film and the member according to the present embodiment can be fixed with a fixture. Examples of the fixing position include the craze film according to the present embodiment and the end portion of the member.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

<Making a craze film>
A craze film was produced by the following method using the same device as the craze forming device described with reference to FIGS. 8 and 9.

(Example 1)
First, an unstretched film made of commercially available crystalline polystyrene (manufactured by Goyo Paper Works Co., Ltd., "SPS film" (syndiotactic polystyrene-based resin film), thickness 50 μm, width 50 mm, elongation at break in the flow direction (MD)) 2.8%, tensile elasticity in the flow direction (MD) of 2.3 GPa, and breaking point stress in the flow direction (MD) of 40 MPa) were prepared as a film for forming a craze. The breaking point elongation, tensile elastic modulus, and breaking point stress are values measured by a measuring method described later. The prepared craze-forming film is a one-layer unstretched film made of crystalline polystyrene and does not have another layer.

Next, the prepared craze-forming film is held in a tense state by a guide roller and a tension applying mechanism, and the craze-forming film is pressed against the edge of the processing blade to locally bend the craze-forming film. A bent portion was formed. Next, the craze-forming film was conveyed via a guide roller or the like, and the bent portion was gradually moved with respect to the craze-forming film. As the processing blade, a hemispherical blade having a tip shape of an edge portion having a radius of 0.5 mm was used. _{At this time, the angle θ 2} formed by the craze forming film at the bent portion 24 was 90 °, the take-up stress was 21 MPa, and the take-up speed was 100 mm / min. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 1 was obtained.

(Example 2)
_{The craze treatment was carried out in the same manner as in Example 1 except that the angle θ 2} formed by the craze forming film at the bent portion was set to 150 ° and the take-back stress was set to 25 MPa. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 2 was obtained.

(Example 3)
_{The craze treatment was carried out in the same manner as in Example 1 except that the angle θ 2} formed by the craze forming film at the bent portion was set to 60 ° and the take-up stress was set to 17 MPa. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 3 was obtained.

(Example 4)
_{The craze treatment was carried out in the same manner as in Example 1 except that the angle θ 2} formed by the craze forming film at the bent portion was set to 40 ° and the take-up stress was set to 9 MPa. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 4 was obtained.

(Example 5)
The craze treatment was carried out in the same manner as in Example 1 except that the take-up stress was 29 MPa instead of 21 MPa. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 5 was obtained.

(Example 6)
As the processing blade, a hemispherical blade having a radius of 1.0 mm was used instead of a hemispherical blade having a radius of 0.5 mm. Further, the take-up stress was set to 33 MPa instead of 21 MPa. Except for the above, the craze treatment was carried out in the same manner as in Example 1. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 6 was obtained.

(Example 7)
_{The angle θ 2} formed by the craze-forming film at the bent portion was set to 120 ° instead of 90 °. The take-up stress was 29 MPa instead of 21 MPa. Further, the pick-up speed was set to 200 mm / min instead of 100 mm / min. Except for the above, the craze treatment was carried out in the same manner as in Example 1. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Example 7 was obtained.

(Comparative Example 1)
Commercially available unstretched polyethylene terephthalate film (crystalline resin but containing amorphous state. Caneron A-PET manufactured by Shinei Kasei Co., Ltd. Thickness 100 μm, width 50 mm, flow direction (MD) breaking point elongation 44%, a tensile elasticity of 1.6 GPa in the flow direction (MD), and a breaking point stress of 33 MPa in the flow direction (MD)) were prepared as a film for forming a craze. The breaking point elongation, tensile elastic modulus and breaking point stress are values measured by the same method as in Example 1.

Next, using the prepared film for forming a craze, a craze treatment was carried out in the same manner as in Example 1. From the above, the film according to Comparative Example 1 was obtained. In addition, the portion in contact with the processing blade was sequentially whitened by the craze treatment, and a transparent film could not be obtained.

(Comparative Example 2)
Commercially available amorphous polystyrene film (manufactured by Oishi Sangyo Co., Ltd., Styrophan (registered trademark) GK, thickness 30 μm, width 50 mm, flow direction (MD) breaking point elongation 3.4%, flow direction (MD) tension An elastic modulus of 1.8 GPa and a breaking point stress of 36 MPa in the flow direction (MD)) were prepared as a craze-forming film.

Next, using the prepared film for forming a craze, a craze treatment was carried out in the same manner as in Example 1. From the above, the film according to Comparative Example 2 was obtained. In addition, the portion in contact with the processing blade was sequentially whitened by the craze treatment, and a transparent film could not be obtained.

(Comparative Example 3)
Using the film for forming a craze of Comparative Example 2, a craze treatment was carried out in the same manner as in Example 4 to obtain a film according to Comparative Example 3.

(Comparative Example 4)
Commercially available pellets of highly crystalline polypropylene resin Prime Polypro (registered trademark) (manufactured by Prime Polymer Co., Ltd., crystallinity 95%) and commercially available β crystal nucleating agent NU-100 (registered trademark) NU-100 (New Japan Rika Co., Ltd.) Was mixed at a mass ratio of 99.8: 0.2. Next, it was put into a single-screw extruder from the hopper section, melted at 230 ° C., passed through a screen, and then extruded from a T-die having an extrusion port width of 300 mm. The extruded resin layer was pressed against a metal mirror surface roll having a surface temperature of 60 ° C. using an air knife to form a film having a thickness of 50 μm. No transverse stretching was performed. The film width was 280 mm, narrower than the extrusion width. Both ears were slit to make a width of 50 mm in order to take out a portion having a uniform thickness from the central portion of the film. The elongation at break point in the flow direction (MD) was 610%, the tensile elastic modulus in the flow direction (MD) was 0.9 GPa, and the stress at the break point in the flow direction (MD) was 28 MPa. The breaking point elongation, tensile elastic modulus and breaking point stress are values measured by the same method as in Example 1. The film was unwound and subjected to a craze treatment in the same manner as in Example 1 to obtain a film.

(Comparative Example 5)
The craze treatment was carried out in the same manner as in Example 1 except that the take-up stress was 36 MPa instead of 21 MPa. As a result, the craze-forming film broke at the bent portion. Therefore, a film subjected to the craze treatment could not be obtained.

(Comparative Example 6)
_{The angle θ 2} formed by the craze-forming film at the bent portion was set to 120 ° instead of 90 °. Further, as the processing blade, a hemispherical blade having a radius of 1.5 mm was used instead of a hemispherical blade having a radius of 0.5 mm. Further, the take-up stress was set to 33 MPa instead of 21 MPa. Except for the above, the craze treatment was carried out in the same manner as in Example 1. As a result, crazes were formed in stripes on the craze-forming film. From the above, the craze film according to Comparative Example 6 was obtained.

<Measurement of break point elongation, tensile modulus and break point stress of film before craze treatment>
The fracture point elongation, tensile elastic modulus and fracture point stress of the craze-forming film (film before craze treatment) according to Examples and Comparative Examples were measured in accordance with JIS K-7127 (1999). Specifically, a tensile compression tester (manufactured by Minebea Co., Ltd.) is used to perform a tensile test under test conditions (measurement temperature 23 ° C., test piece length 90 mm, test length 50 mm, test piece width 15 mm, tensile speed 100 mm / min). went. Next, the elongation at break (%), the tensile elastic modulus (GPa), and the stress at break (MPa) were determined by automatic analysis using the data processing software built into the testing machine.

<Measurement of the average value of the distance L between adjacent crazes, the number of crazes per 500 μm length, and the fine craze spacing ratio>
For the films of Examples and Comparative Examples, the average value of the distance L between adjacent crazes was determined. Specifically, it was obtained as follows. The results are shown in Table 1.
Using an optical microscope, the side of the film that was not exposed to the craze processing blade was observed as the eyepiece side. The length of 500 μm was set to an observable magnification in the direction orthogonal to the processing blade during the craze processing, and the observation image was taken with the focus on the film surface. The captured image was printed on A3 size paper. The length of 500 μm observed at this time was enlarged to 275 mm (magnification 550 times). A straight line orthogonal to the craze was drawn near the center of the observation section, and the intersection of the straight line and the craze was marked. The distance between the marks was measured along the straight line. The measured interval was converted into the length before enlargement according to the value of the magnification at the time of observation, and was defined as the interval L between adjacent crazes.
The average value of the value L measured by the above method was calculated. The average value was compared with each measured value L, and it was confirmed whether the measured value L contained a value 10 times or more or 1/10 or less of the average value. If it was included, that value was treated as an abnormal value, and the average value of the values excluding the abnormal value was taken as the average value of the distance L between adjacent crazes. When no abnormal value was included, the average value was used as it was as the average value of the distance L between adjacent crazes.
Further, the number of measured values L (when the abnormal value is excluded, the number after removing the abnormal value) is defined as the number of crazes per 500 μm in length.
Further, the ratio obtained by dividing the number of values L having a value of 10 μm or less (when the abnormal value is excluded, the corresponding number after excluding the abnormal value) by the number of crazes per 500 μm of the length is expressed as a percentage. The fine craze interval ratio was used.
However, when the film was whitened, it was judged to be unmeasurable. Here, whitening means that when observed with an optical microscope by the above method, a short craze-like structure is generated in a direction substantially parallel to the processing blade during the craze treatment, but its length (parallel to the processing blade during the craze treatment). The length in the direction of) is 500 μm or more, which means that it is hardly observed. If the length is less than 500 μm, the incident light is hardly deflected, and a desired amount of deflected light cannot be obtained. In addition, the transparency of the film is reduced, and the film becomes cloudier than before the treatment. Further, the state in which a craze-like structure was hardly formed on the film and there was no film having a length of 500 μm or more was also regarded as unmeasurable (the number of crazes was 0).
In the films of Comparative Example 1 and Comparative Example 2, those having a thickness of 500 μm or more were not observed, and almost all of them were 100 μm or less.

<Measurement of craze width>
For the films of Examples and Comparative Examples, the average value of the width of the craze was calculated. Specifically, it was obtained as follows. The surface of the film on the side where the craze processing blade did not hit was observed. An electron microscope was used for the observation. At a magnification of 20000 times, an observation image was acquired by observing three craze portions near the center of the obtained film in the transport direction. For each observation image, the width of the craze portion was measured at three points. The average value of each of the three measured values (9 measured values in total) of each of the above three observed images was taken as the width of the craze. However, if the film was whitened or no craze was formed, measurement was not possible.

<Measurement of craze depth>
For the films of Examples and Comparative Examples, the average value of the craze depth was calculated. Specifically, it was obtained as follows. A sample for observing a cross section (a cross section perpendicular to the processing blade and a cross section in the thickness direction) was prepared from an arbitrary part in the center of the film of Examples and Comparative Examples using a section preparation device (ultramicrotome). Using an optical microscope, the magnification was set so that 10 or more crazes were included in the field of view, and arbitrary two points of the cross-section observation sample were observed. The depths of 20 or more observed crazes were measured, and the average value was taken as the craze depth. In the measurement of the depth of each craze, if the craze reaches from the interface on the side where the processing blade is not applied to the interface on the side where the processing blade is applied to the film of each layer, the layer thickness (in the case of a single layer). (Film thickness) and the depth of the craze are equal, and if the craze is stopped in the middle, that point is the end point of the craze, and the linear distance from the interface on the side where the processing blade of the film is not applied to the end point is the end point of the craze. It was the depth.

<Measurement of polarized light fraction>
Using the measuring device for measuring the deflection light fraction described with reference to FIG. 3, the measurement was performed as follows. In this example, a goniometer (model: GENESIA (registered trademark) Gonio / FFP, manufactured by Genesia Co., Ltd.) was used as the measuring device. Hereinafter, for convenience, the same reference numerals as those in FIG. 3 will be used for description. The goniometer 30 is located on the opposite side of the light source 34 with the light source 34 capable of changing the incident angle of light with respect to the irradiation position 32 and the irradiation position 32, and changes the angle with respect to the irradiation position 32. It is a device including a light receiving unit 36 capable of

<Measurement of polarized light fraction Rr _30>
(1) The measuring device 30 was prepared, and the craze films according to Examples and Comparative Examples were set so that the direction of the craze was vertical with respect to the angle-changeable surfaces of the light source 34 and the light receiving unit 36.
(2) From the light source 34 to one surface of the craze film (in FIG. 3, the lower surface of the craze film 10: this is the surface on which the edge portion of the processing blade was not pressed during the craze treatment). On the other hand, light was irradiated at an _{incident angle θ 1 = 30 °.}
(3) When the vertical direction of the craze film was 0 °, the angle α of the light receiving portion 36 was moved from + 90 ° to −90 °, and the amount of emitted light was measured at 1 ° intervals. Of these, the sum of the measured values at 90 points from -1 ° to −90 ° was defined as the deflection light amount Rd ₃₀ . The angle α represents the side including the position of the light source 34 and the surface object with respect to the craze film surface (in FIG. 3, the upper left side of the craze film) as a minus.
(4) The same measurement was performed without setting the craze film, and the total of the measured values at 181 points from + 90 ° to −90 ° was taken as the initial integrated light intensity Ri ₃₀ .
(5) The deflection light fraction Rr ₃₀ (%) = (Rd ₃₀ / Ri ₃₀ ) × 100 was calculated.
The results are shown in Table 1.

<Measurement of polarized light fraction Rr _50>
(6) The measuring device 30 was prepared, and the craze film was set so that the direction of the craze was vertical with respect to the angle-changeable surfaces of the light source 34 and the light receiving unit 36.
(7) From the light source 34 to one surface of the craze film (in FIG. 3, the lower surface of the craze film 10: this is the surface on which the edge portion of the processing blade was not pressed during the craze treatment). On the other hand, light was irradiated at an _{incident angle θ 1 = 50 °.}
(8) When the vertical direction of the craze film was 0 °, the angle α of the light receiving portion 36 was moved from + 90 ° to −90 °, and the amount of emitted light was measured at 1 ° intervals. Of these, the sum of the measured values at 90 points from -1 ° to −90 ° was defined as the deflection light amount Rd ₅₀ . The angle α represents the side including the position of the light source 34 and the surface object with respect to the craze film surface (in FIG. 3, the upper left side of the craze film) as a minus.
(9) The same measurement was performed without setting the craze film, and the total of the measured values at 181 points from + 90 ° to −90 ° was taken as the initial integrated light intensity Ri ₅₀ .
(10) The deflection light fraction Rr ₅₀ (%) = (Rd ₅₀ / Ri ₅₀ ) × 100.
The results are shown in Table 1.
In this embodiment, the lower surface of the craze film (the surface on which the edge portion of the processing blade is not pressed during the craze treatment) is irradiated with light to obtain a deflection light fraction Rr ₃₀ and deflection light. Although the fraction Rr ₅₀ is measured, for example, when it is used as a daylighting film as shown in FIG. 4, it is not necessary to arrange the surface on which the edge portion of the processing blade is not pressed on the outdoor side. In actual use, any side of the craze film may be arranged in either direction. That is, in this embodiment, the edge portion of the processing blade is not pressed in order to make more concrete how the _{deflection light fraction Rr 30} and the deflection light fraction Rr _{50 are measured and obtained.} It is merely decided to irradiate the surface with light for measurement, and it is not intended from which surface the light is emitted during actual use.

<Evaluation of ceiling illuminance>
FIG. 10A is a schematic view of the measuring device used for evaluating the ceiling illuminance, and FIG. 10B is a diagram for explaining the position and size of the window W. FIG. 10 (c) is a diagram for explaining the ceiling illuminance measurement position and the size, and is a diagram when looking up at the top (ceiling) from inside the measuring device. First, a measuring device having a window W on the wall portion B was prepared. The position and size of the window W are as shown in FIG. 10 (b). The device does not allow light to enter from other than the window W, and the inner wall of the device is matte white. Each craze film of the example was installed on the inside of the device of the window W portion so that the direction of the craze (direction of the processing blade) was parallel to the device installation surface.
FIG. 11 is a schematic view when the craze film is installed in the evaluation of the ceiling illuminance. As shown in FIG. 11, a spot-type LED light (model number) as a light source T at a position where the incident angle to the film is 45 ° in the height direction, the lateral direction is from the front, and the distance to the film is 50 cm. : NLSM05S-AC, manufacturer: Nikki Corporation, 1 m ahead illuminance 1570 lux, total luminous flux 280 lm) was installed, and white light (multicolor light) was emitted from the light source T toward the film. A digital illuminance meter (model number: IM-600, manufacturer: Topcon Techno House Co., Ltd.) as a light receiving unit S at the illuminance measurement position on the ceiling surface, which is 225 mm from the window to the indoor side (see FIG. 10 (c)). Was installed and the illuminance was measured. That is, the light receiving portion S has a reflection angle of 45 ° with respect to the height direction. The illuminance when the above measurement is performed without installing the film is 124 lux. Here, the incident angle of 45 ° corresponds to the general solar altitude of 9:00 to 16:00 during the daytime hours of the spring and autumn equinoxes in Japan (Tokyo). The results are shown in Table 1.

<Measurement of total light transmittance of film>
The total light transmittance of the films of Examples and Comparative Examples was measured using a haze meter NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS-K7361. At the time of measurement, light was input from the same side as the light input side in the measurement of the deflection light fractions Rr ₃₀ and Rr _{50 (the surface side where the edge portion of the processing blade was not pressed).} The results are shown in Table 1.

<Measurement of breaking point elongation, tensile modulus and breaking point stress of film after craze treatment>
The elongation at break, the tensile elastic modulus, and the stress at break in the flow direction (MD) of the films (films after craze treatment) according to Examples and Comparative Examples were measured. The specific measurement method of the breaking point elongation, tensile elastic modulus and breaking point stress of the film after the craze treatment is the same as the measurement of the breaking point elongation, tensile elastic modulus and breaking point stress of the film before the craze treatment. be. The results are shown in Table 1.

In the evaluation of the main ceiling illuminance, the ceiling illuminance is preferably 400 lux or more, more preferably 500 lux or more, still more preferably 1000 lux or more, and particularly preferably 1300 lux or more. When it is 400 lux or more, it is preferable that the room is bright and easy to feel when used for daylighting. The ceiling illuminance is preferably 3000 lux or less, more preferably 2500 lux or less, still more preferably 2000 lux or less, and particularly preferably 1800 lux or less. By setting it to 3000 lux or less, it is preferable that the room does not feel dazzling when used for daylighting.

From the above results, it can be seen that the film of the example is suitable for daylighting because the ceiling illuminance in the evaluation of the ceiling illuminance is 400 lux or more and 3000 lux or less. In particular, the ceiling illuminance received at a reflection angle of 45 ° with respect to a light source of 1570 lux irradiated at an incident angle of 45 ° is 400 lux or more and 3000 lux or less (more preferably 500 lux or more, further preferably 1000 lux or more, particularly preferably 1300 lux or more; Since it is more preferably 2500 lux or less, further preferably 2000 lux or less, particularly preferably 1800 lux or less), the film of the present embodiment including the film of the example can be suitably used for daylighting in various countries around the world.

10, 11 Craze film 12 Resin layer 14 (Resin layer) Craze 15 Other resin layer 16 (Other resin layer) Craze 17 Other layers 20, 21 Craze forming film 22 Resin layer 25 Other resin layer 27 Other Layer 30 Measuring device 32 Irradiation position 34 Light source 36 Light receiving part 50 Craze forming device 52 Processing blade 54 Edge part 56 Guide roller

Claims (6)

The craze extending in a certain direction has a resin layer formed in stripes, and has a resin layer.
The resin layer contains a crystalline polystyrene-based resin and is unstretched.
Craze film deflecting light fraction _{Rr 30} measured by the following measurement methods deflecting light fraction _{Rr 30} is characterized in that 15 to 65%.
<Measuring method of polarized light fraction Rr _30>
(1) A light source capable of changing the incident angle of light with respect to the irradiation position and a light receiving position located on the opposite side of the light source with the irradiation position sandwiched between them and capable of changing the angle with respect to the irradiation position. A measuring device including the unit is prepared, and the craze film is set so that the direction of the craze is vertical with respect to the angle-changeable surface of the light source and the light receiving unit.
(2) Light is irradiated from the light source to one surface of the craze film at an incident angle θ ₁ = 30 °.
(3) When the vertical direction of the craze film is 0 °, the angle α of the light receiving portion is moved from + 90 ° to −90 °, and the amount of emitted light is measured at 1 ° intervals. Of these, the total of the measured values at 90 points from -1 ° to −90 ° is defined as the deflection light amount Rd ₃₀ . The angle α represents the side including the position of the light source and the surface object with respect to the craze film surface as a minus.
(4) The same measurement is performed without setting the craze film, and the total of the measured values at 181 points from + 90 ° to −90 ° is defined as the initial integrated light intensity Ri ₃₀ .
(5) The deflection light fraction Rr ₃₀ (%) = (Rd ₃₀ / Ri ₃₀ ) × 100. The craze film according to claim 1, wherein the deflection light fraction Rr ₅₀ measured by the following method for measuring the deflection light fraction Rr _{50 is 5 to 55%.}
<Measuring method of polarized light fraction Rr _50>
(6) A light source capable of changing the incident angle of light with respect to the irradiation position and a light receiving position located on the opposite side of the light source with the irradiation position sandwiched between them and capable of changing the angle with respect to the irradiation position. A measuring device including the unit is prepared, and the craze film is set so that the direction of the craze is vertical with respect to the angle-changeable surface of the light source and the light receiving unit.
(7) Light is irradiated from the light source to one surface of the craze film at an incident angle θ ₁ = 50 °.
(8) When the vertical direction of the craze film is 0 °, the angle α of the light receiving portion is moved from + 90 ° to −90 °, and the amount of emitted light is measured at 1 ° intervals. Of these, the total of the measured values at 90 points from -1 ° to −90 ° is defined as the deflection light amount Rd ₅₀ . The angle α represents the side including the position of the light source and the surface object with respect to the craze film surface as a minus.
(9) The same measurement is performed without setting the craze film, and the total of the measured values at 181 points from + 90 ° to −90 ° is defined as the initial integrated light intensity Ri ₅₀ .
(10) The deflection light fraction Rr ₅₀ (%) = (Rd ₅₀ / Ri ₅₀ ) × 100. Craze film according to claim 1 or 2 average distance L _C between adjacent craze between L _{C ',} characterized in that it is in the range of 10 to 40 [mu] m. Has a resin layer
The resin layer contains a crystalline polystyrene-based resin and is unstretched.
The tensile elastic modulus in the flow direction (MD) of the resin layer is 2.0 GPa or more and 3.2 GPa or less, and the breaking point elongation in the flow direction (MD) of the resin layer is 0.2% or more and 30% or less. A film for forming crazes. A step A of preparing the film for forming a craze according to claim 4, and
The craze-forming film is pressed against the edge portion of the processing blade to form a bent portion on the craze-forming film, and the bent portion is moved relative to the craze-forming film. A method for producing a craze film, which comprises a step B of forming crazes in a striped shape on a resin layer. _{The fifth aspect of claim 5, wherein the angle θ 2} formed by the craze-forming film at the bent portion is 15 ° to 160 °, and the tip shape of the edge portion is a hemisphere having a radius of 1 mm or less. A method for manufacturing a craze film.

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