JP7139869B2 - Films and laminates - Google Patents

Description

The present invention relates to films and laminates.

In general, plastic films have properties such as being lightweight, chemically stable, easy to process, flexible and strong, and mass-producible, and are used for various purposes. Its applications include, for example, packaging materials for packaging foodstuffs and pharmaceuticals, drip packs, shopping bags, posters, tapes, optical films used for liquid crystal televisions, protective films, window films for bonding to windows, A wide variety of products such as vinyl houses and building materials. Specific materials include, for example, thermoplastic resins such as polyethylene, polypropylene, polystyrene, acrylic polymethyl methacrylate, polycarbonate, polyamide, polyethylene terephthalate, and polybutylene terephthalate, and thermosetting resins such as epoxy resins, polyurethanes, and polyimides. are mentioned.

Appropriate plastic materials are selected depending on the application, and a plurality of types of these materials are stacked to form a laminate. There is also a method of use in which a plurality of plastic materials are mixed in one layer to compensate for the shortcomings of a single material. In many cases, appropriate film materials are selected based on heat resistance, mechanical strength, or transparency. Furthermore, as shown in Patent Document 1, the surface of a plastic sheet is also given a design such as unevenness.

JP 2017-166096 A

By the way, the mechanical properties of a plastic film are generally determined by the material and layer structure. For this reason, strength-oriented materials tend to have low elongation, and there is a strong demand for film materials that can ensure sufficient elongation while having high strength. In addition, barrier packaging materials in which a vapor deposition layer is laminated on a base material have the problem that when stretched, the vapor deposition layer immediately cracks and the barrier property disappears. There is also a strong demand for film materials that ensure the Furthermore, for example, polylactic acid films are strong and biodegradable, and are attracting attention from the viewpoint of environmental protection, but their applications are limited due to their relatively low elongation and poor impact resistance. . In this way, in response to the demand for film materials that can achieve both strength and elongation, countermeasures such as mixing multiple materials and bonding multiple types of films are being considered. At present, it is difficult to obtain a sufficient effect.
In addition, plastic films generally have the characteristic of having a positive Poisson's ratio, that is, when they are pulled in one direction, they shrink in a direction perpendicular thereto. Therefore, even if the film is easily stretchable, there is a problem that a stronger force is required to stretch the film in two directions than in one direction. For example, when you want to inflate a bag when filling it with contents or in a subsequent process, stretching in two directions rather than in one direction often increases the volume of the bag. There is also a request to

In view of the problems of the prior art, the present invention provides a film that has good strength and elongation regardless of the plastic material, and can be easily stretched in two directions, while suppressing labor and cost during production. , an object of the present invention is to provide a laminate using the same.

In order to achieve the above object, the first aspect of the present invention is
The front and back surfaces of the film are divided into at least one or more sections,
the compartment has an edge that separates the compartment;
in at least one of said compartments,
The surface of the partition has a mountain-shaped first surface ridgeline and a valley-shaped first surface ridgeline extending between the edges while periodically changing the direction and matching the phase of the direction change. ,
From the direction change point of the mountain-shaped first surface ridgeline to the direction change point of the adjacent valley-shaped first surface ridgeline that exists in the direction in which the mountain-shaped first surface ridgeline is the farthest, there is a mountain The adjacent mountain-shaped first surface has a second surface ridgeline in the shape of a ridge, and is present in the direction in which the valley-shaped first surface ridgeline is the farthest from the direction change point of the valley-shaped first surface ridgeline. Having a valley-shaped second surface ridge between the ridge and the direction change point,
On the rear surface of the partition, a valley-shaped first rear surface ridgeline and a second rear surface ridgeline are provided at positions corresponding to the mountain-shaped first rear surface ridgeline and the second rear surface ridgeline of the front surface, and a valley-shaped second rear surface ridgeline is provided on the front surface. Having a mountain-shaped first back surface ridgeline and a second back surface ridgeline at positions corresponding to the first surface ridgeline and the second surface ridgeline,
The mountain-shaped first front surface ridgeline and second front surface ridgeline of the front surface, the valley-shaped first rear surface ridgeline and second rear surface ridgeline of the rear surface, and the valley-shaped first front surface ridgeline and second front surface ridgeline of the front surface. , a concave-convex structure is formed with the mountain-shaped first back surface ridgeline and second back surface ridgeline on the back surface as inflection points of the cross section,
The film is made of a thermoplastic resin or a curable resin, and the uneven structure is imparted to the surface by transfer molding,
In any cross section including the thickness direction of the film, the height difference of the film is greater than the thickness of the film and is within the range of 5 μm to 500 μm.
It is a film characterized by

Furthermore, the second aspect of the present invention is
The front and back surfaces of the film are divided into at least one or more sections,
the compartment has an edge that separates the compartment;
in at least one of said compartments,
On the surface of the partition, each pair of mountain-shaped first surface ridgelines and valley-shaped first surface ridgelines extending between the edges while periodically changing the direction,
The pair of mountain-shaped first surface ridgelines extend so as to be separated from each other until each mountain-far direction change point after approaching each other to each mountain-near direction change point,
A pair of said valley-shaped first surface ridgelines, between said pair of said mountain-shaped first surface ridgelines, after approaching each other to respective valley-near direction changing points, are separated from each other to respective valley-toward direction changing points. extended to
When the film is viewed in the thickness direction, the near-mountain direction changing point and the near-valley direction changing point existing on the same line are defined as the near-mountain point and the near-valley point, respectively, and the near-mountain direction existing on the same line. Let the conversion point and the valley direction conversion point be the mountain far point and the valley far point, respectively,
having a mountain-shaped second surface ridgeline between the near-mountain point and the near-valley point;
Having a valley-shaped second surface ridgeline between the crest point and the valley point,
Having a mountain-shaped third surface ridgeline between the valley point and the valley point,
having a valley-shaped third surface ridgeline between the near-valley points and the near-valley points;
On the rear surface of the partition, valley-shaped first rear surface ridgelines, second rear surface ridgelines, and third rear surface ridgelines are provided at positions corresponding to the mountain-shaped first rear surface ridgelines, second rear surface ridgelines, and third rear surface ridgelines of the front surface. and a mountain-shaped first rear surface ridgeline, a second rear surface ridgeline and a third rear surface ridgeline at positions corresponding to the valley-shaped first front surface ridgeline, second front surface ridgeline and third front surface ridgeline,
The film is characterized in that the height difference of the film is greater than the thickness of the film in any cross section including the thickness direction of the film.

According to the present invention, a film that has good strength and elongation regardless of the plastic material and can be easily stretched in two directions while suppressing labor and cost during production, and a laminate using the same. can provide.

It is a perspective view which shows an example of the perspective view in the film of this embodiment. It is a sectional view showing an example of a sectional view in a film of this embodiment. It is a top view which shows an example of the top view which observed the film of this embodiment from upper direction. It is a perspective view which shows the modification of the film of this embodiment. 1 is a cross-sectional view showing an example of a one-dimensional bellows-like film; FIG. 1 is a perspective view showing an example of a one-dimensional accordion-like film; FIG. FIG. 4 is a cross-sectional view of a film according to another embodiment of the film of the present embodiment; It is a sectional view showing an example of a sectional view in a film of this embodiment. It is a perspective view which shows an example of the perspective view in the film of this embodiment. It is a top view which shows an example of the top view which observed the film of this embodiment from upper direction. FIG. 10 is a perspective view showing an example of a perspective view of a film according to another embodiment of the present invention; It is a top view which shows an example of the top view which observed the film of another embodiment of this invention from upper direction. FIG. 4 is a cross-sectional view of a film according to another embodiment; FIG. 4 is a cross-sectional view of a film according to another embodiment; FIG. 4 is a cross-sectional view of a film according to another embodiment; FIG. 4 is a cross-sectional view of a film according to another embodiment; FIG. 3 is a cross-sectional view of a laminate in which films are laminated together; FIG. 4 is a surface view of another embodiment of a multi-section film; FIG. 4 is a surface view of another embodiment of a multi-section film; 1 is a perspective view of Example 1 before being stretched; FIG. 1 is a perspective view after stretching Example 1. FIG. 1 is a top view of Example 1 before being stretched; FIG. 1 is a top view of Example 1 after being stretched. FIG. It is the side view (a) before stretching and stretching of Example 1, and the side view (b) after stretching and stretching. It is the side view (a) before stretching and stretching of Example 1, and the side view (b) after stretching and stretching. It is a graph which shows the elongation of each direction of each Example and a comparative example. 4 is a graph showing the Y-direction elongation and applied load in each example and comparative example. 4 is a graph showing elongation when the direction of elongation is changed in Example 1. FIG. 1 is a perspective view showing a model (enlarged from the real thing) of a film 1 according to a first embodiment; FIG. FIG. 10 is a perspective view showing a model (enlarged from the real thing) of the film 1 according to the second embodiment;

EMBODIMENT OF THE INVENTION Below, embodiment of the film concerning this invention is described with reference to drawings. Each figure is a schematic diagram, and the size, shape, etc. of each part are appropriately exaggerated for easy understanding. In order to simplify the explanation, the same reference numerals are given to the corresponding parts in each figure. The terms front and back used herein are used for convenience, and either of a pair of sides of the film may be the front or back.
As used herein, "compartment" is a term that indicates an area provided on the front or back surface of the film, and the outermost periphery of each compartment is referred to as the "edge". There may be one section or multiple sections present in a series of films. When there are multiple compartments, the edges of each compartment may be in contact with each other or may be spaced apart. Edges do not need to have a unique shape or region, but they may.

(Film structure)
FIG. 1 is an example of a perspective view of the film of the present embodiment, FIG. 2 is a cross-sectional view taken along the xz plane in FIG. 1, and FIG. It is a top view when viewed in the direction of the film (also referred to as viewing in the thickness direction of the film). In FIG. 1, a solid line or a broken line indicates a mountain ridge and a dotted line indicates a valley ridge. In FIG. 3, a dashed line indicates a mountain ridge and a dotted line indicates a valley ridge. FIG. 29 shows a model of the film 1 according to this embodiment.
The film according to this embodiment has a periodic concave-convex structure on the front and back surfaces. "Ridge line" refers to the boundary line between surfaces, and more specifically, it is obtained by finding the intersections or inflection points of lines in the surface cross section or the back surface cross section of the uneven structure for each of multiple cross sections and connecting them. say the line

As shown in FIG. 1, the film 1 has, on the surface 2 as a single section, a zigzag mountain-like first surface in the y direction in the figure while changing the direction at the turning points PM and PV, respectively. A ridgeline 2a and a valley-like first surface ridgeline 2b extend. As viewed in the thickness direction of the film 1, when the mountain-shaped first surface ridgeline 2a is translated, it overlaps with the valley-shaped first surface ridgeline 2b.

The mountain-like first surface ridgelines 2a and the valley-like first surface ridgelines 2b are alternately arranged in a zigzag (direction change) phase. In FIG. 3, from the direction change point PM of the mountain-like first surface ridgeline 2a, the direction change point PV of the adjacent valley-like first surface ridgeline 2b exists in the direction in which the mountain-like first surface ridgeline 2a is the farthest. (That is, the adjacent direction change point PV on the center line of the two mountain-shaped first surface ridgelines 2a extending from the direction change point PM, and the direction change point PV farther from the ridgeline) An adjacent mountain that has a mountain-shaped second surface ridgeline 2c in between and exists in the direction in which the valley-shaped first surface ridgeline 2b is the farthest from the direction change point PV of the valley-shaped first surface ridgeline 2b The direction change point PM of the first surface ridgeline 2a (that is, the adjacent direction change point PM on the center line of the two valley-shaped first surface ridgelines 2b extending from the direction change point PV, It has a valley-like second surface ridgeline 2d between the ridgeline and the turning point PM) which is farther from the ridgeline. That is, the adjacent mountain-shaped first surface ridgeline 2a and valley-shaped first surface ridgeline 2b are connected by the mountain-shaped second surface ridgeline 2c and the valley-shaped second surface ridgeline 2d.

When the film 1 is viewed from above (in the thickness direction), it becomes as shown in FIG. The mountain-shaped second surface ridgeline 2c is formed in the direction in which the mountain-shaped first surface ridgeline 2a is the farthest from the direction change point PM at which the direction of the mountain-shaped first surface ridgeline 2a changes (the x direction in FIG. 3 or − The valley-shaped second surface ridgeline 2d exists between the direction change point PV at which the direction of the adjacent valley-shaped first surface ridgeline 2b existing in the x direction) changes, and the valley-shaped second surface ridgeline 2d The direction of the adjacent mountain-shaped first surface ridgeline 2a existing in the direction (x direction or -x direction in FIG. 3) in which the mountain-shaped first surface ridgeline 2b is the farthest from the direction change point PV at which the direction changes is It exists up to the changing direction change point PM. At this time, the mountain-like second surface ridgeline 2c and the valley-like second surface ridgeline 2d are on the same straight line when viewed from above. In other words, when viewed in the direction of FIG. 3, the mountain-shaped first surface ridgeline 2a and the valley-shaped first surface ridgeline 2b illustrate a state in which triangular waves having the same amplitude and period travel in the y direction. is similar to
In addition, on the back surface 3 as a single section, positions corresponding to the mountain-shaped first surface ridgeline 2a, the valley-shaped first surface ridgeline 2b, the mountain-shaped second surface ridgeline 2c, and the valley-shaped second surface ridgeline 2d. , a valley-shaped first rear surface ridgeline 3a, a mountain-shaped first rear surface ridgeline 3b, a valley-shaped second rear surface ridgeline (not shown), and a mountain-shaped second rear surface ridgeline (not shown). It should be noted that the front edge and the back edge may be curved lines, and in such a case, the "direction changing point" means the "inflection point".

As shown in the cross-sectional view of FIG. 2, the film 1 has a so-called bellows shape. This accordion shape is not one-dimensional but two-dimensional. As shown in FIG. 1, when viewed from the surface 2 side, it has a shape in which zigzag ridges are lined up. FIG. 4 shows a perspective view of the film 1 when the film thickness is reduced to the limit. Adding this shape has the effect of increasing the elongation of the film 1 in two directions. A feature of such films is referred to as bidirectional ductility.
Moreover, the height difference H of the film is greater than the thickness T of the film in any cross section including the thickness direction of the film. The height difference H of the film represents the difference in distance in the film thickness direction between the highest position and the lowest position on the front surface 2 (or the back surface 3), and has the length shown in FIG. 2, for example.

(Action of film)
First, in order to simplify the action of the highly ductile film 1 according to the present embodiment, consider a bellows-like film extending in one dimension as shown in FIGS. When pulled in the left-right direction of FIG. 5, that is, in the direction in which the periodic concave-convex structure is arranged, shape deformation first occurs due to elastic deformation, and then plastic deformation occurs in part of the shape deformation. If you continue to pull, the tensile stress will reduce the height difference of the uneven structure, and it will become flat, making it impossible to deform the shape. On the other hand, normal flat films only undergo tensile deformation under the same tensile conditions. Therefore, it can be said that the accordion-shaped film can be stretched more easily than a normal film by performing shape deformation in a plurality of stages as described above. In this shape deformation region, less force is required to obtain the same elongation. Ultimately, however, tensile deformation becomes dominant, so the breaking strength is almost the same as that of a film of the same thickness.

According to the film 1 having high ductility according to the present embodiment, it has a two-dimensional bellows shape, and for example, when pulled in the x direction in FIG. 1, it can be easily stretched in the x direction as described above. At the same time, by deforming the peak-shaped and valley-shaped second ridgelines 2c, 2d, etc., it is also possible to extend in the y direction. Of course, if it is stretched in the y direction, it stretches not only in the y direction but also in the x direction.

At this time, since the height difference H of the film is larger than the film thickness T in an arbitrary cross section including the thickness direction of the film, the shape deformation can be caused as described above, and the effect of elongation can be obtained. If the height difference H of the film is smaller than the film thickness T, it will be difficult for the film to deform in shape when pulled. Here, the height difference of the film in an arbitrary cross section including the thickness direction of the film coincides with the height difference between the mountain-like first surface ridgeline 2a and the valley-like first surface ridgeline 2b.

In this way, even a film made of a material generally considered to have low elongation can be made highly ductile in two directions by devising its shape. In other words, the strength and elongation of the film are compatible, and the film can be stretched in two directions at the same time.

At this time, by appropriately controlling the shape of the film cross-section, that is, the shape of the concave-convex structure on the surface 2 and the back surface 3 of the film 1, arbitrary ductility can be obtained. For example, if it is desired to stretch the film greatly without breaking it, it is preferable to increase the height difference H of the film 1 and make adjustments so that the ridge top or ridge trough is not too rounded. .

Here, when the film 1 is viewed in the thickness direction, the angle formed by the valley-shaped first surface ridgeline 2b sandwiching the direction change point PV (or the mountain-shaped first surface ridgeline 2a sandwiching the direction change point PM) is θ (FIG. 3), and in the direction (y direction in FIG. 1) in which the continuous mountain-shaped first surface ridgeline 2a and a plurality of direction changing points PM, which are the intersections of the mountain-shaped second surface ridgeline 2c, overlap. Assuming that the angle formed by the back surface 3 sandwiching the mountain-shaped first back surface ridge line 3a when viewing the film 1 is φ (FIG. 1), the elongation in the x and y directions can be obtained by adjusting the angles φ and θ. Ease can be controlled. By decreasing the angle θ, the elongation in the y direction can be increased, and by decreasing the angle φ, it is possible to increase the elongation in the x direction. When the angle .theta. is small, first, the shape is changed so as to widen this angle, thereby extending in the y direction. At this time, the angle φ also changes and extends in the x direction. However, since the change in the angle φ is small while the angle θ is small, the y-direction is well stretched, but the x-direction is small. The elongation in the x-direction becomes large. Thus, it is possible to control the ductility in two directions depending on the structure.

The film 1 having high ductility according to the present embodiment can improve ductility by changing the shape of the entire film at the initial stage of stretching. In other words, the film is not elongated by stretching the material itself from the initial stage of stretching, unlike a film with a normal flat surface. In the film according to the present embodiment, local strain (elongation or shrinkage) occurs in the uneven structure at the beginning of stretching, and the shape changes due to the local strain, thereby obtaining high ductility.

The cross-sectional view of the concave-convex structure does not have to be the periodic triangular shape shown in FIG. 2, and may be wavy as shown in FIG. This shape determines the overall film elongation and local strain described above. Furthermore, the mountain-shaped ridgeline and the valley-shaped ridgeline may not necessarily be clearly visible. For example, as shown in FIG. 7, a film 1 having a wavy periodic cross-sectional shape is assumed. In such a film 1, the mountain-shaped ridgeline passes through the vertex (inflection point) P1 of the convex cross section and extends in a zigzag direction perpendicular to the paper surface, and the valley-shaped ridgeline is the vertex of the concave cross-section ( It passes through the inflection point P2 and extends in a zigzag direction perpendicular to the paper surface. The extension of this zigzag does not necessarily have to be linear, and may be in a shape with a rounded apex or in a wavy shape.

FIG. 8 is an example of a cross-sectional view of the film 1 having high ductility according to this embodiment in the x direction in FIG. As shown in FIG. 8, by increasing the height difference H between peaks and valleys of the uneven structure, the entire film can be easily stretched. In the film adopting the shape A, for example, by coating the surface with a hard layer (for example, vapor deposition or hard coating), it is possible to obtain the effect that the hard coating film can be stretched. In other words, for example, by applying it to a vapor deposition barrier film, it is possible to give elasticity in two directions while suppressing breakage of the vapor deposition layer. Examples of deposited films include alumina and silica. As another example, the same thing can be said for a material in which a metal such as aluminum is vapor-deposited to provide a light-shielding property or a design. Of course, the hard layer is not limited to a vapor deposition film in a narrow sense, and is not particularly limited to dry coating, wet coating, and the like.

(Thickness of film, height of irregularities, etc.)
Also, the thickness T of the film 1 is preferably 500 μm or less, more preferably 100 μm or less. This is because if the film thickness T is increased, the force required to stretch the film increases, and the effect of the film of the present invention in that it can be easily stretched is lost. In addition, the thickness of the film does not necessarily have to be uniform. In the film after the uneven shape processing, the thickness of the film in the vicinity of the ridge may be different from the thickness of the film in other portions.
Also, the height difference H between peaks and valleys of the uneven structure is preferably 5 μm to 500 μm. If the height difference H between peaks and valleys is less than 5 μm, it is difficult to obtain the effect of adjusting the distortion. It is not preferable because the thickness becomes thicker and it becomes difficult to fulfill its role as a film. More preferably, it should be in the range of 10 μm to 200 μm.
Furthermore, the thickness of the film 1 is more preferably half or less of the height difference H between the peaks and valleys of the uneven structure. By doing so, better elongation can be obtained.

Moreover, it is preferable that the concave-convex structure is a periodic structure that is regularly arranged. By avoiding a random structure, the intended ductility can be easily obtained, and at the same time, the design and manufacture of the concave-convex structure can be simplified. The period of the structure should be in the range of 10 μm to 1000 μm. Here, the period of the structure indicates the period of the structure in the direction in which the mountain-like or valley-like first surface ridge lines are arranged or in the direction orthogonal thereto. However, providing a random uneven structure is optional.
Intervals between adjacent mountain-like first surface ridgelines 2a and valley-like first surface ridgelines 2b may be equal as shown in FIGS. 1 and 3, or may be different as shown in FIGS.
In addition, the height difference between the mountain-shaped first surface ridgeline 2a and the valley-shaped first surface ridgeline 2b may be different within the same section, but if it is substantially constant, the production load can be reduced. preferable. Moreover, it is preferable that the mountain-shaped ridgeline and the valley-shaped ridgeline are on the same plane (a plane parallel to the xy plane) (the same applies to the following embodiments).

(Film with another two-dimensional structure)
In the film 1 having high ductility according to the present embodiment described above, as shown in FIGS. However, as shown in FIGS. 11 and 12, two mountain-shaped first surface ridgelines 2a and two valley-shaped first surface ridgelines 2b are arranged alternately, and adjacent mountain-shaped first surface ridgelines 2a and 2b are arranged alternately. The ridgelines 2a or the valley-shaped first surface ridgelines 2b are arranged with a zigzag phase shifted by 180 degrees, and the adjacent mountain-shaped first surface ridgelines 2a and the valley-shaped first surface ridgelines 2b are aligned in zigzag phase. It is possible to obtain the effect of the present invention even with a shape in which they are arranged side by side. FIG. 11 is a perspective view showing an example of this embodiment, and FIG. 12 is a top view thereof. FIG. 30 shows a model of the film 1 according to this embodiment.

More specifically, a pair of mountain-like first surface ridgelines 2a and valley-like first surface ridgelines 2b extending while periodically changing directions are provided between edges on the surface of the partition. The pair of mountain-like first surface ridgelines 2a approach each other up to their near-mountain direction changing points PMN, and then extend away from each other to their respective far-mountain direction changing points PMF. Further, the pair of valley-shaped first surface ridgelines 2b, between the pair of mountain-shaped first surface ridgelines 2a, approach each other to the respective valley-near direction changing points PVN, and then reach the respective valley-toward direction changing points. They extend away from each other to the PVF. A pair of the mountain-like first surface ridgeline 2a and the valley-like first surface ridgeline 2b have a symmetrical shape across the middle line.

When the film 1 is viewed in the thickness direction, the peak-near direction changing point PMN and the valley-near direction changing point PVN, which are present on the same line L1, are defined as the peak-near point and the valley-near point, respectively, and are present on the same line L2. Assuming that the mountain distance direction conversion point PMF and the valley distance direction conversion point PVF are respectively the mountain distance point and the valley distance point, there is a mountain-shaped second surface ridge line 2c between the mountain near point and the valley near point, It has a valley-shaped second surface ridge line 2d between the valley end point and the valley end point, and has a mountain-shaped third surface ridge line 2i between the valley end point and the valley end point. It has a valley-like third surface ridge 2j between the point and the near-valley point.

That is, in the region between the mountain-shaped first surface ridgeline 2a and the valley-shaped first surface ridgeline 2b, the direction changing point PMN at which the direction of the mountain-shaped first surface ridgeline 2a changes, as in FIGS. to the direction change point PVN where the direction of the adjacent valley-shaped first surface ridgeline 2b changes in the direction in which the mountain-shaped first surface ridgeline 2a is the farthest (the x direction or -x direction in FIG. 12) In addition, the direction in which the valley-shaped first surface ridgeline 2b is farthest from the turning point PVF where the direction of the valley-shaped first surface ridgeline 2b changes (Fig. 12), there is a valley-shaped second surface ridgeline 2d up to the direction change point PMF where the direction of the adjacent mountain-shaped first surface ridgeline 2a changes.

In other words, in the region between the valley-shaped first surface ridgelines 2b, a line connecting the turning points at which the direction of the adjacent ridgelines 2b changes. If it faces outward, it has mountain-like third surface ridgelines 2j and 2i.

Furthermore, adjacent to the mountain-shaped first surface ridgeline 2a, a mountain-shaped adjacent surface ridgeline 2aA is provided. The mountain-shaped first surface ridgeline 2a and the mountain-shaped adjacent surface ridgeline 2aA approach each other to the inside direction changing points PMF and PMA, and then separate from each other to the outside direction changing points PMN and PMB. extends to Here, the far direction changing point of the mountain-like first surface ridgeline 2a corresponds to the inside direction changing point, and the near-mountain direction changing point of the mountain-like first surface ridgeline 2a corresponds to the outside direction changing point.

When the film 1 is viewed in the thickness direction, the inside direction changing points PMF and PMA that are closest to each other on the line L2 are set as adjacent points, and on the line L1, the points adjacent to the adjacent points are on the same side. When the side direction changing points PMN and PMB are the adjacent ridge points, there is a mountain-like fourth surface ridge line 2g between the adjacent ridge near points, and a valley-like fourth surface ridge line between the adjacent ridge far points. 2h. The rear surface of the partition has a valley-shaped fourth rear surface ridgeline (not shown) at a position corresponding to the mountain-shaped fourth front surface ridgeline on the front surface.

In other words, the mountain-shaped first surface ridgeline 2a and the mountain-shaped adjacent surface ridgeline 2aA are symmetrical with respect to their intermediate line, and in the region between them, the direction change points where the directions of the adjacent ridgelines 2a and 2aA change. , there are fourth surface ridgelines 2g and 2h which are mountain-shaped when the ridgelines 2a and 2aA are directed inward and valley-shaped when the ridgelines 2a and 2aA are directed outward. Clearly, the crest-like adjacent surface ridge 2aA can become the crest-like first surface ridge 2a and have the relationship described above with its adjacent valley-like first surface ridge. By repeatedly forming these ridge lines, a film 1 having an arbitrary size can be formed.
In other words, when a pair of mountain-shaped first surface ridgelines 2a and valley-shaped first surface ridgelines 2b are formed into a ridgeline set consisting of four ridgelines, a plurality of ridgeline sets are provided in parallel. One of the mountain-shaped first surface ridgelines 2a that does not sandwich the valley-shaped first surface ridgeline 2b among the adjacent ridgeline sets becomes the mountain-shaped adjacent surface ridgeline 2aA with respect to the other.

In addition, on the back surface 3 as a single section, at positions corresponding to the surface ridgelines 2a, 2b, 2c, 2d, 2g, 2h, 2i, and 2j, when the surface ridgelines are mountain-like, they become valley-like. In some cases, it has a mountain-like rear surface ridgeline (not shown). That is, when the back surface 3 is viewed in the thickness direction of the film, the dashed-dotted line and the dotted line in FIG. 12 are opposite to each other.
The shapes of FIGS. 11 and 12 appear to be greatly different from those of FIGS. 1 and 3, but they are basically the same shape, and the action and characteristics of the films are also the same.

(Characteristics of film)
In addition, since the film 1 of the present embodiment having high extensibility has the effect of stretching when stress is applied, it has high impact resistance and high impact absorption due to the crushing of the concave-convex structure. Furthermore, when the film 1 having high ductility of the present embodiment is laminated, the uneven shape of the film 1 has voids above and below the film, that is, air layers, so it also has the property of high heat insulation. ing.

The highly ductile film 1 of the present embodiment also has a feature of having high transparency in spite of having an uneven structure on the front surface 2 and the back surface 3 . The positions of the shapes of the uneven structures on the front surface 2 and the back surface 3 are periodically matched and reversed, and the front surface 2 and the back surface 3 are arranged substantially in parallel, so that according to Snell's law, light is incident from the front surface 2 or the back surface 3. The incident light is refracted inside the film and changes its angle, but when it is emitted from the rear surface 3 or the front surface 2, the light becomes the incident angle. In other words, the film appears transparent because very little light is refracted as it passes through the thin film of this embodiment. In other words, the film of this embodiment looks like a film having a normal flat surface at first glance, but can be further provided with a high ductility function in two directions. At this time, by stretching in two directions at the same time, it is possible to obtain a peculiar property in which the substantial Poisson's ratio becomes negative, that is, the material stretches horizontally when it is stretched vertically. As described above, it is possible to design how to extend in the vertical and horizontal directions by means of the concave-convex structure.

Furthermore, bending stiffness can be improved in either direction. Bending stiffness is determined by the integral of the product of the geometrical moment of inertia and Young's modulus. The film 1 of the present embodiment having high ductility has a larger geometrical moment of inertia than a normal film having the same amount of resin, so that the bending rigidity can be increased.

(film material)
The material of the film 1 is preferably thermoplastic resin or curable resin (thermosetting resin, UV curable resin, etc.). Examples of thermoplastic resins include polyethylene, polypropylene, polystyrene, polymethyl methacrylate, ethylene vinyl acetate, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, polylactic acid, cyclic polyolefin, polycarbonate, and polyamide. , polyethylene terephthalate, polybutylene terephthalate, and derivatives thereof, but are not particularly limited. Examples of curable resins include epoxy resins, polyurethanes, polyimides, and derivatives thereof, but are not particularly limited. These materials may be used alone, or a plurality of these materials may be used in combination. Alternatively, a multilayer structure (also referred to as a laminate) in which a plurality of layers are superimposed may be formed.

(Film manufacturing method)
As for the manufacturing method, for example, a hot press method or an extrusion method can be used.

In the hot press method, the formed film can be produced by passing it between a pair of heating rolls having an uneven surface or through a pair of heated plate-like pressing machines. At this time, it is important that the upper and lower concave shapes and convex shapes are precisely aligned, and that the front and back surfaces of the film after pressing have a structure in which peaks and valleys are continuously repeated.
In addition, in the extrusion molding method, in the cooling process for filming the molten resin extruded from the T-die, a pair of cooling rolls and nip rolls with uneven surfaces corresponding to the uneven structure are used to apply nip pressure. By cooling while cooling, a concave-convex structure can be attached. In this method as well, it goes without saying that precise alignment of the irregularities of the cooling roll and the nip roll affects the film performance.

Furthermore, in another extrusion molding method, a plurality of extruders are used to co-extrude a plurality of different resins by a feed block method or a multi-manifold method to obtain a film having a multilayer structure of two or more layers. can be done. At this time, in the cooling process for forming a film, a cooling roll with unevenness on the surface corresponding to the uneven structure and a nip roll without unevenness are used to cool while applying nip pressure, so that the film surface in contact with the cooling roll An uneven structure can be attached. Furthermore, at this time, when the height difference H between the peaks and valleys of the uneven structure is large with respect to the film thickness T of the first resin layer in contact with the cooling roll, the same applies to the interface between the first resin layer and the adjacent second resin layer. An uneven structure is added to Therefore, by peeling off the second resin layer from the multilayer film after cooling, the first resin layer having an uneven structure on both sides, that is, the film 1 having high extensibility can be obtained.
In addition, any method for adding the concave-convex structure, such as injection molding, can be selected, and the method is not particularly limited.

(Laminate)
The film 1 having high ductility may consist of one layer, or as shown in FIG. 17, by increasing the layer structure, a plurality of films 1 may be laminated to form a laminate. For example, the first layer may be a gas barrier layer or a drug non-adsorbing layer, and the second layer may be an inexpensive resin layer (bulking layer), a high rigidity layer, or a layer that compensates for the physical properties of the first layer. Of course, the lamination of films may be three or more layers. Moreover, it is also possible to form a laminate in which functional layers such as a deposition layer, a hard coat layer, and an antireflection layer are laminated in a post-process on the highly ductile film 1 .

Alternatively, as shown in FIGS. 13 to 16, a laminate 5 may be formed by laminating another film 6 onto the film 1 having high ductility. Here, according to the embodiment of FIGS. 13 and 14, another film 6 is directly adhered to the film 1 to form the laminate 5 . On the other hand, according to the embodiment of FIGS. 15 and 16, another film 6 is adhered to the film 1 via the pressure-sensitive adhesive layer (or adhesive layer) 7 to form the laminate 5 . Another film 6 is preferably a functional layer having a specific function.

(Application of film)
For example, it is conceivable to use the highly extensible film 1 or a laminate using the film as a barrier film, a packaging material, or a backing for an adhesive patch such as a poultice. In addition, a stretchable decorative film that decorates this film, a film that can change the appearance depending on the viewing direction by using the structure of this film, and a film that changes the appearance by changing the shape by stretching it further. Applications to films and the like are conceivable, but the uses are not limited to these.

As an application example, the backing of a patch is required to have resistance to drugs and additives contained in the patch, non-adsorptive properties, or barrier properties. All of these requirements can be met by adding an uneven structure to a material with high chemical resistance, non-adsorption properties, and barrier properties to form a film 1 with high extensibility. Materials with high chemical resistance, non-adsorption properties, and high barrier properties include, for example, cyclic polyolefins, ethylene-vinyl alcohol copolymers, and polyethylene terephthalate. In addition, since the film 1 having high extensibility has less stress applied at the same elongation, it is possible to make it difficult to feel a sense of discomfort such as being pulled at the time of expansion and contraction.

(another embodiment of the film)
18 and 19 are surface views showing an embodiment in which a series of films has a plurality of sections, with dashed-dotted lines indicating mountain ridges and dotted lines indicating valley ridges. In FIG. 18, the film 1 has four sections 1A each surrounded by an edge Fr. The mountain-shaped ridgeline 2a and the valley-shaped ridgeline 2b extend in a zigzag shape to form the embodiment of the present invention. Although not shown, the same applies to the mountain-shaped ridgeline and the valley-shaped ridgeline on the back side. As shown in the figure, adjacent sections 1A may face the same direction or may face different directions. Although FIG. 19 shows a case where the sections 1A have different shapes, they may be different in this way. In the drawing, the adjacent sections 1A have gaps, but they do not have to have clear boundaries. Also, any number of sections 1A can be present on a series of films.
One compartment has the property of extending in two directions as described above. Therefore, by having a non-stretchable gap around the section 1A, it is possible to solve the processing process problem that the film stretches during processing. In the final product, the film 1 extending in two desired directions can be provided by cutting or punching each section.

Although the embodiments of the present invention have been exemplified above, it goes without saying that the present invention is not limited to the above embodiments. Moreover, it is arbitrary to combine and use the above embodiments.

Examples prepared by the present inventors will be described in detail below, but the present invention is not limited only to the following examples.

The elongation and strength of the examples and comparative examples were calculated using the general-purpose nonlinear finite element analysis solution Marc (registered trademark). Comparative Example 1 is a flat film without an uneven structure, and Example 1 is a film having the structure shown in FIG. The angles θ and φ in Example 1 are 120.0 degrees and 93.5 degrees, respectively. The film material was set to have a Young's modulus of 500 MPa, Poisson's ratio of 0.35, and constant elastic deformation. As for the size, the pitch in the x direction is 200 μm, the pitch in the y direction is 208 μm, the height H is 37.6 μm, and the film thickness T is 10 μm. Examples 2 to 9 are films obtained by changing the angles θ and φ of the film of Example 1, and take the values shown in Table 1, respectively.

Analysis of the displacement in the x-direction and the load applied in the y-direction when each Example/Comparative Example 1 was stretched in the y-direction was performed. The results are shown in FIGS. 26 and 27, respectively. Further, an analysis of the displacement in the y direction when Example 1 was stretched in the x direction was carried out.

FIG. 21 is a perspective view after stretching in the x direction with the x-direction end of Example 1 fixed, and FIGS. 24 and 25 are side views of Example 1 before stretching (a) and after stretching (b) (viewed from y direction and x direction, respectively). ). The meaning of coloring in each figure is that white indicates no displacement, and that distortion (displacement) increases from white to gray to black.

As can be seen from FIG. 21, FIG. 23, or FIG. 24 and FIG. 25, Example 1 extends only in the y direction and extends in the x direction as well.

FIG. 26 is a graph showing x-direction elongation when the films of Examples and Comparative Examples are stretched in the y-direction, with the x-direction displacement on the vertical axis and the y-direction displacement on the horizontal axis. As can be seen from FIG. 26 , not only Example 1 but also each example expands in the x direction by stretching in the y direction, but in Comparative Example 1, conversely, it contracts. This indicates the Poisson effect that ordinary materials contract in one direction when stretched in another direction. On the other hand, in each example, the first thing that extends in the x direction is the negative Poisson effect due to the change in shape (described above) peculiar to the example. disappeared), it shows that it shrinks due to the positive Poisson effect. In other words, since the slope of each example becomes negative from a certain value, it indicates that there is a Poisson effect similar to that of Comparative Example 1 thereafter.
Furthermore, when comparing Examples 1 to 9, the smaller the angle θ, the higher the elongation effect in the y direction due to the shape deformation extending in the x direction. I understand. However, once the peak is exceeded, the y-direction is extended in the y-direction by material elastic deformation as in Comparative Example 1, not by shape deformation. Also, it can be seen that the smaller the angle φ, the longer it extends in the x direction.

FIG. 27 is a graph showing the relationship between elongation and load when the films of Examples and Comparative Examples are stretched in the y direction, with the load on the vertical axis and the displacement in the y direction on the horizontal axis. From FIG. 27, in each example, the load did not rise linearly according to elongation, but abruptly rises from the point of inflection. The range up to this point of inflection is the shape deformation region (region where the slope of the graph is positive in FIG. 26), and it can be seen that a small force is required for stretching in this region. After the elongation effect due to shape deformation disappears (in the region where the slope of the graph turns negative in FIG. 26), the required force rises sharply. In other words, it can be easily stretched with a small force within the range where it can be stretched in two directions, but in order to stretch it further, it needs to have the same strength as a normal shapeless film (Comparative Example 1). I understand.

FIG. 28 is a graph showing the displacement in the y direction when the film of Example 1 is pulled in the x direction. It was found that no matter which direction the film was stretched in the x direction, it was stretched in the other direction (the x direction and the y direction, respectively), and the properties of the films of Examples did not particularly depend on the stretching direction.

1 Highly extensible film 1A Section 2 Surface 2a Mountain-like first surface ridgeline 2b Valley-like first surface ridgeline 2c Mountain-like second surface ridgeline 2d Valley-like second surface ridgeline 2i Mountain-like third surface Ridgeline 2j Valley-shaped third front-surface ridgeline 2g Mountain-shaped fourth front-surface ridgeline 2h Valley-shaped fourth front-surface ridgeline 3 Rear surface 3a Valley-shaped first rear-surface ridgeline 3b Mountain-shaped first rear-surface ridgeline 5 Laminate 6 Another film 7 Adhesive layer (or adhesive layer)

Claims (11)

The front and back surfaces of the film are divided into at least one or more sections,
the compartment has an edge that separates the compartment;
in at least one of said compartments,
The surface of the partition has a mountain-shaped first surface ridgeline and a valley-shaped first surface ridgeline extending between the edges while periodically changing the direction and matching the phase of the direction change. ,
From the direction change point of the mountain-shaped first surface ridgeline to the direction change point of the adjacent valley-shaped first surface ridgeline that exists in the direction in which the mountain-shaped first surface ridgeline is the farthest, there is a mountain The adjacent mountain-shaped first surface has a second surface ridgeline in the shape of a ridge, and is present in the direction in which the valley-shaped first surface ridgeline is the farthest from the direction change point of the valley-shaped first surface ridgeline. Having a valley-shaped second surface ridge between the ridge and the direction change point,
On the rear surface of the partition, a valley-shaped first rear surface ridgeline and a second rear surface ridgeline are provided at positions corresponding to the mountain-shaped first rear surface ridgeline and the second rear surface ridgeline of the front surface, and a valley-shaped second rear surface ridgeline is provided on the front surface. Having a mountain-shaped first back surface ridgeline and a second back surface ridgeline at positions corresponding to the first surface ridgeline and the second surface ridgeline,
The mountain-shaped first front surface ridgeline and second front surface ridgeline of the front surface, the valley-shaped first rear surface ridgeline and second rear surface ridgeline of the rear surface, and the valley-shaped first front surface ridgeline and second front surface ridgeline of the front surface. , a concave-convex structure is formed with the mountain-shaped first back surface ridgeline and second back surface ridgeline on the back surface as inflection points of the cross section,
The film is made of a thermoplastic resin or a curable resin, and the uneven structure is imparted to the surface by transfer molding,
In any cross section including the thickness direction of the film, the height difference of the film is greater than the thickness of the film and is within the range of 5 μm to 500 μm.
A film characterized by: 2. The film according to claim 1, wherein the height difference between the mountain-shaped first surface ridgeline and the valley-shaped first surface ridgeline adjacent to each other is substantially constant within the section. The front and back surfaces of the film are divided into at least one or more sections,
the compartment has an edge that separates the compartment;
in at least one of said compartments,
On the surface of the partition, each pair of mountain-shaped first surface ridgelines and valley-shaped first surface ridgelines extending between the edges while periodically changing the direction,
The pair of mountain-shaped first surface ridgelines extend so as to be separated from each other until each mountain-far direction change point after approaching each other to each mountain-near direction change point,
A pair of said valley-shaped first surface ridgelines, between said pair of said mountain-shaped first surface ridgelines, after approaching each other to respective valley-near direction changing points, are separated from each other to respective valley-toward direction changing points. extended to
When the film is viewed in the thickness direction, the near-mountain direction changing point and the near-valley direction changing point existing on the same line are defined as the near-mountain point and the near-valley point, respectively, and the near-mountain direction existing on the same line. Let the conversion point and the valley direction conversion point be the mountain far point and the valley far point, respectively,
having a mountain-shaped second surface ridgeline between the near-mountain point and the near-valley point;
Having a valley-shaped second surface ridgeline between the crest point and the valley point,
Having a mountain-shaped third surface ridgeline between the valley point and the valley point,
having a valley-shaped third surface ridgeline between the near-valley points and the near-valley points;
On the rear surface of the partition, valley-shaped first rear surface ridgelines, second rear surface ridgelines, and third rear surface ridgelines are provided at positions corresponding to the mountain-shaped first rear surface ridgelines, second rear surface ridgelines, and third rear surface ridgelines of the front surface. and a mountain-shaped first rear surface ridgeline, a second rear surface ridgeline and a third rear surface ridgeline at positions corresponding to the valley-shaped first front surface ridgeline, second front surface ridgeline and third front surface ridgeline,
A film, wherein the height difference of the film is greater than the thickness of the film in any cross section including the thickness direction of the film. Adjacent to the mountain-shaped first surface ridgeline, having a mountain-shaped adjacent surface ridgeline extending while periodically changing the direction,
The mountain-shaped first surface ridgeline and the mountain-shaped adjacent surface ridgeline approach each other to their respective inside direction changing points and then extend away from each other to their respective outside direction changing points,
When the film is viewed in the thickness direction, the inside direction changing points that are closest to each other are defined as adjacent peak near points, and the outside direction changing points adjacent to the adjacent peak near points on the same side are defined as adjacent peak distant points. ,
Having a mountain-shaped fourth surface ridgeline between the adjacent points near the mountain,
having a valley-like fourth surface ridgeline between the adjacent mountain far points;
The rear surface of the partition has a valley-shaped fourth rear surface ridgeline at a position corresponding to the mountain-shaped fourth front surface ridgeline on the front surface, and a mountain-shaped rear surface at a position corresponding to the valley-shaped fourth front surface ridgeline on the front surface. having a fourth back surface edge of
4. The film of claim 3, characterized by: When the pair of mountain-shaped first surface ridgelines and the valley-shaped first surface ridgeline are defined as ridgeline sets, a plurality of ridgeline sets are provided in parallel, and between the adjacent ridgeline sets, one of the mountain-shaped first surface ridgelines that does not sandwich the valley-shaped first surface ridgeline becomes the mountain-shaped adjacent surface ridgeline with respect to the other;
5. The film of claim 4, characterized by: 6. The film according to any one of claims 1 to 5, wherein the film has a thickness of 500 µm or less. 7. The film according to any one of claims 1 to 6, wherein the height difference of the film is within the range of 5 μm to 500 μm in any cross section including the thickness direction of the film. 8. The film according to any one of claims 1 to 7, wherein a plurality of said sections are provided. A laminate comprising a functional layer laminated on at least one surface of the film according to any one of claims 1 to 8. A laminate comprising a plurality of the films according to any one of claims 1 to 8 laminated together. A laminate comprising the film according to any one of claims 1 to 8 and another film laminated thereon.

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