JP2019089321A - Film, laminate and production method of film - Google Patents

Abstract

To provide a film having good bending strength and elongation regardless of a plastic material while suppressing labor hours and costs of production, a laminate using the film, and a production method of the film.SOLUTION: A film 1 is divided, on a top surface 2 and a back surface 3 thereof, into at least one segment, and the segment has an edge that defines the segment. In at least one of the segments, the top surface 2 of the segment has a convex top surface ridge line 2a and a concave top surface ridge line 2b extending between the edges; and the back surface 3 of the segment has a concave back surface ridge line 3a at a position corresponding to the convex top surface ridge line 2a on the top surface, and a convex back surface ridge line 3b at a position corresponding to the concave top surface ridge line 2b on the top surface. A height difference between the convex top surface ridge line and the concave top surface ridge line is greater than the thickness of the film; the film has a thickness of 500 μm or less; and a cross-sectional secondary moment per unit length on a first cross-section is smaller than a cross-sectional secondary moment per unit length of a second cross-section different from the first cross-section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a film, a laminate, and a method of producing a film.

  In general, plastic films have properties such as light weight, chemical stability, ease of processing, flexibility and strength, mass production, etc., and are used for various things. As its application, for example, packaging materials for packaging food products and medicines, drip packs, shopping bags, posters, tapes, optical films used for liquid crystal televisions, etc., protective films, window films to be bonded to windows, A wide variety of plastic houses, construction materials, etc. Specific materials include, for example, thermoplastic resins such as polyethylene, polypropylene, polystyrene, methyl acryl polyacrylate, polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, epoxy resins, thermosetting resins such as polyurethane, polyimide, etc. Can be mentioned.

  Depending on the application, appropriate plastic materials are selected, and further, it is also possible to stack them into a plurality of types to form a laminate. There are also uses in which a plurality of plastic materials are mixed in one layer to compensate for the disadvantages of a single material. In many cases, appropriate film materials are selected due to heat resistance, mechanical strength, or transparency. Furthermore, as shown to patent document 1, giving a design, such as an unevenness | corrugation, on the surface of a plastic sheet is also performed.

Unexamined-Japanese-Patent No. 2017-166096

By the way, the mechanical properties of the plastic film are generally determined by the material and layer configuration. For this reason, in a material that emphasizes strength, the elongation tends to be small, and a film material that can ensure sufficient elongation while having high strength is highly desired. Moreover, the barrier packaging material which laminated | stacked the vapor deposition layer on the base material has a subject that a crack will immediately occur in the vapor deposition layer and the barrier property disappears when it is stretched, and the elongation while suppressing the destruction of the vapor deposition layer There is also a strong demand for film materials that have secured.
In addition, it is highly desirable to improve mechanical properties such as bending strength with as little resin material as possible. For example, polylactic acid films have attracted attention from the viewpoint of environmental protection because they have strength and biodegradability, but their use is limited due to their relatively low elongation and inferior impact resistance.
As described above, in response to the demand for a film material that can achieve both strength and elongation, countermeasures have been considered by mixing multiple materials or laminating multiple types of films, but while it takes time and cost, At present, it is difficult to obtain sufficient effects.

  In view of the problems of the prior art, the present invention is a film, a laminate using the same, and a film having good bending strength and elongation regardless of the plastic material while suppressing labor and cost at the time of manufacture. The purpose is to provide a manufacturing method.

In order to achieve the above object, one aspect of the present invention is
The front and back of the film are divided into at least one or more compartments,
The compartments have an edge dividing the compartments,
In at least one of the compartments,
In the surface of the section, it has mountain-shaped surface ridges and valley-shaped surface ridges extending between the edge and the edge;
In the back surface of the section, a valley-shaped back surface ridgeline is provided at a position corresponding to a mountain-shaped surface surface ridge line of the surface, and a mountain-shaped back surface ridgeline is provided at a position corresponding to the valley-shaped surface surface ridge line ,
The height difference between the mountain-like surface ridge line and the valley-like surface ridge line is larger than the thickness of the film,
The thickness of the film is 500 μm or less,
The moment of inertia of area per unit length of the first cut surface when the film is cut along the first direction along the surface ridgeline and the thickness direction of the film is orthogonal to the first direction It is a film characterized by being smaller than the second moment of area per unit length of the second cut surface when the film is cut along the second direction and the thickness direction of the film.

  According to the present invention, it is possible to provide a film having good bending strength and elongation regardless of the plastic material, a laminate using the same, and a method of producing the film while suppressing the labor and cost at the time of production. .

It is sectional drawing which shows an example of sectional drawing in the 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 sectional drawing which shows the modification of the film of this embodiment. It is the figure which calculated and showed the local distortion amount at the time of pulling the film (a) concerning this Embodiment, and the film (b) with the conventional flat surface in the left-right direction of a figure. When the shape of a film is changed, it is the graph which showed the relationship between the whole film elongation and the maximum value of local distortion. It is sectional drawing shown changing the cross-sectional shape of a film. It is sectional drawing of the different direction of the film of this embodiment. It is a figure which shows an example of the manufacturing method of the film of this implementation, (a) shows the co-extrusion process in the manufacturing method of the film of this implementation, (b) is obtained by the co-extrusion process in the manufacturing method of the film of this implementation. (C) shows a film obtained by separating the film obtained by the coextrusion step in the method for producing a film of this embodiment. It is a figure which shows another example of the manufacturing method of the film of this implementation, (a) shows the extrusion process in another manufacturing method of the film of this implementation, (b) is another manufacturing method of the film of this implementation. The obtained film is shown. It is a figure which shows another example of the manufacturing method of the film of this implementation, (a) shows the state before the press in another manufacturing method of the film of this implementation, (b) is another manufacturing of the film of this implementation. The state in the press in a method is shown, (c) is a figure of the film obtained by the another manufacturing method of the film of this implementation. It is a perspective view of the laminated body which laminated | stacked films. (A) is a cross-sectional view of a laminate according to another embodiment, (b) is a cross-sectional view of a laminate according to another embodiment, (c) is a stack according to another embodiment It is a sectional view of a body. FIG. 7 is a front view of another embodiment of a film with multiple compartments. FIG. 7 is a front view of another embodiment of a film having two vertical and horizontal sections. FIG. 7 is a front view of another embodiment of a film with multiple compartments. FIG. 7 is a front view of another embodiment of a film having a single section; FIG. 7 is a cross-sectional view of another embodiment of a film. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows roughly the cross section of the film of an Example and a comparative example, (a) shows a flat cross section, (b) shows a waveform cross section, (c) shows a trapezoid cross section.

Hereinafter, embodiments of a film according to the present invention will be described with reference to the drawings. Each drawing is a schematic view, and the size, shape, etc. of each part are appropriately exaggerated for easy understanding. Further, in order to simplify the description, the corresponding parts of the respective drawings are denoted by the same reference numerals. The front surface and the back surface used in the present specification are for convenience, and any one of the pair of surfaces in the film may be the front surface or the back surface.
As used herein, "section" is a term that refers to the area provided on the front or back of the film, and the outermost periphery of each section is referred to as the "edge". There may be one or more compartments present in the series of films. When there are a plurality of sections, the edges of the sections may be in contact with each other or may be separated. With regard to the edge, it is not necessary for the edge to have a unique shape or area, but it may be present.

(Structure of film)
FIG. 1 is a cross-sectional view showing an example of a cross-sectional view of a film of the present embodiment, and FIG. 2 is a perspective view, and the film extends in the left-right direction of the figure. The film according to the present embodiment has a periodic uneven structure on the front and back surfaces. Such a concavo-convex structure has a mountain ridge line and a valley ridge line as described below. The “ridge line” refers to a boundary between a surface and a surface, and more specifically, the intersection or inflection point of a line in the surface cross section or the back surface cross section of the concavo-convex structure is obtained for each of a plurality of cross sections Say a line.

  As shown in FIGS. 1 and 2, the film 1 has straight chevrons 2a and valleys 2b extending in parallel from one edge side to the other edge side in the direction perpendicular to the paper surface on the surface 2 as a single section. Are alternately arranged at equal intervals, and in the back surface 3 as a single section, at a position corresponding to the mountain ridge 2a and the valley ridge 2b (a position substantially corresponding to the thickness direction), in the direction perpendicular to the drawing. Straight valley ridges 3a and mountain ridges 3b extending in parallel from one edge side to the other edge side are alternately provided at equal intervals. The ridge lines 2a and 2b provided on the front surface may be referred to as front surface ridge lines, and the ridge lines 3a and 3b provided on the back surface may be distinguished from each other as back surface ridge lines.

  As shown in FIGS. 1 and 2, the film 1 has a so-called bellows shape. The addition of this shape has an effect of enhancing the bending strength and the extensibility of the film 1. The pitches P of the mountain ridges 2a and the valley ridges 2b may be equal or different, and the pitch of the valley ridges 3a and the mountain ridges 3b is the same. In addition, the mountain ridge 2a, the valley ridge 2b, and the valley ridge 3a and the ridge ridge 3b are orthogonal to the side edges of the front surface 2 and the rear surface 3 as viewed from above in FIGS. It may be angled. The distance in the height direction between the ridgeline 2a and the ridgeline 2b or the ridgeline 3a and the ridgeline 3b is referred to as a film height difference. The height difference H of the film 1 of the present embodiment is preferably larger than the thickness T of the film 1.

(Function of film)
According to the film 1 according to the present embodiment, since it has a so-called bellows-like structure, bending rigidity can be improved as compared with a normal flat film. Further, compared with a film having a concavo-convex structure of only the surface, if it is the same resin amount, the height difference of the mountain-valley shape can be made high, so the bending rigidity can be further improved. In other words, since it can be realized with a small amount of resin to ensure equal bending rigidity, it can be manufactured inexpensively.

  Here, it is generally known that the flexural rigidity is given by the product of the Young's modulus of the material used for the film 1 and the moment of inertia of area determined by the shape of the film 1. When the film 1 is required to have another new performance, usable materials are limited. Therefore, it can be said that improving the second moment of area is effective for bending rigidity.

  When a horizontal line is taken as the X axis in the cross section of the film, the moment of area I of the cross section with respect to the X axis is expressed by the following equation (1) from the micro area element dA of the film cross section and the distance y from the X axis of the micro element Ru.

I = ∫y ² dA (1)

  According to the equation (1), one having a shape which spreads in an arbitrary direction (here, the one in which the value y from the X axis is larger) is smaller than the minute elements are densely arranged at a certain place It shows that the value of the cross-sectional second moment I becomes large.

  In the film 1 according to the present embodiment, since the bellows-like structure is used, the film 1 having a greater difference in height than the uneven structure of only the surface can be produced when the same resin amount is used, and the cross section 2 in the formula (1) It is possible to increase the next moment I, and the bending rigidity is improved.

  Moreover, according to a part of film 1 concerning this embodiment, extensibility can be provided. For example, in a film in which a mountain-like shape extends in one direction as shown in FIG. 1 or in a part having a mountain-like shape in two directions as represented by Miura fold, the horizontal direction in FIG. When pulling in the direction in which the concavo-convex structure is arranged, first, the concavo-convex structure mainly collapses and spreads (area that extends without applying much force) and the collapsed concavo-convex structure further stretches and becomes almost flat ( Reach the yield point through the area where the force is applied). When it is further pulled, plastic deformation occurs and necking occurs to finally reach the breaking point. Here, the term "necking" refers to a phenomenon in which the entire width of the film to be pulled does not extend uniformly, but locally produces a necking. On the other hand, in a normal flat film, elastic deformation occurs only a short distance after the film starts to extend, and the yield point is reached immediately. When it is further pulled, plastic deformation occurs and necking occurs to finally reach the breaking point. Therefore, it can be said that the film 1 of the present embodiment can be stretched more easily than a normal film by performing shape deformation in a plurality of steps as described above. In this shape deformation area, the force required to obtain the same elongation can be reduced. However, since the unevenness is finally crushed to be flat and the characteristic value of the film material becomes dominant, the breaking strength is almost equal to that of the film of the same thickness. At this time, when the height difference H of the film is larger than the thickness T of the film 1, it is possible to cause the shape deformation as described above, and it is possible to obtain an extending effect. When the height difference H of the film is smaller than the thickness T of the film 1, the shape deformation does not occur when it is pulled.

  In this way, even a film made of a material that is generally considered to have a low flexural strength and elongation can be made to have high rigidity and high extensibility by devising the shape. That is, it is possible to simultaneously secure the bending strength of the film in one direction and the elongation of the film in another direction.

  At this time, by appropriately controlling the shape of the cross section of the film, that is, the shapes of the concavo-convex structure of the front surface 2 and the back surface 3 of the film 1, arbitrary extensibility can be obtained. For example, when it is desired to extend the film greatly without breaking it, if the height difference H of the valleys of the concavo-convex structure is increased and the ridge top or ridge valley is made less rounded, adjustment is performed. Good. Moreover, the bending strength of a film can be improved by enlarging the height difference H of the peak-and-valley of the uneven structure of the surface 2 of the film 1, and the back surface 3. As shown in FIG.

  In the film 1 having high extensibility according to the present embodiment, the extensibility can be improved by changing the shape of the entire film at the initial stage of tension. That is, the film is not stretched by the fact that the material itself is stretched from the initial stage of pulling as in a film having a normal flat surface. In the film according to the present embodiment, when the film is pulled in the direction in which the concavo-convex structure is arranged, local distortion (elongation or contraction) occurs in the concavo-convex structure at the beginning of tension, and the shape changes accordingly. You can get sex. Therefore, the elongation of the whole film can be freely adjusted by appropriately setting the shape of the concavo-convex structure.

  The concavo-convex structure does not have to be a periodic triangular shape as shown in FIG. 1 and may be a waveform or a rectangular shape, and can be changed as appropriate. This shape determines the overall film elongation and local strain described above. Furthermore, the mountain ridges and valley ridges may not necessarily be clearly visible. For example, as shown in FIG. 3, a film 1 having a wave-like periodic cross-sectional shape is assumed. In the film 1, the mountain ridge passes through the apex (inflection point) P1 in the convex cross section and is a straight line extending in the direction perpendicular to the sheet, and the valley ridge is the peak in the concave cross section at a position opposite to the mountain ridge. It can be a straight line extending in the direction perpendicular to the drawing sheet passing through the bending point P2.

(Film stress and strain)
FIG. 4 (a) illustrates, for example, the local distortion amount in the case of pulling in the lateral direction of the figure for one pitch of the uneven structure in the film 1 having high extensibility as shown in FIG. FIG. 4 (b) is a diagram showing, as a comparative example, a local flat film when a flat conventional film is pulled in the lateral direction of the figure and calculated and illustrated. The general purpose nonlinear finite element analysis solution Marc (registered trademark) was used for the calculation. The cross section of the film shown in FIG. 4 shows that the distortion increases as the color increases from white to gray to black. When the above calculation results are compared, the tensile stress is uniform in the case of a flat film as shown in FIG. 4 (b). On the other hand, as shown in FIG. 4A, in the film 1 of the present embodiment, there are places where high distortion is generated on both sides of the apex, and therefore tensile stress at the other parts of the film is It turns out that there is an effect to reduce.

(Relation between the overall elongation of the film and the maximum value of local distortion)
FIG. 5 shows the relationship between the overall elongation and the maximum value of the local strain when the shape of the uneven structure of the film is changed, and the vertical axis is the maximum value of the local strain, The horizontal axis is the elongation of the entire film, and a film having no uneven structure shown by a dotted line (without a shape) is taken as a comparative example. Moreover, the cross-sectional shape of the film 1 with high extensibility used by calculation of FIG. 5 is shown in FIG. The shape A shown in FIG. 6 (a) has a relatively large height difference H between the peaks and valleys of the uneven structure, and the shape C shown in FIG. 6 (c) has a relatively small height difference H between the peaks and valleys of the uneven structure In the shape B shown in FIG. 6B, the height difference H between the peaks and valleys of the concavo-convex structure is about the middle. It can be seen from FIG. 5 that in the film 1 having high extensibility of the present embodiment, the relationship between the overall elongation and the maximum value of the local strain largely changes due to the uneven structure.

  For example, as shown in FIG. 5, by making the height difference H of the peaks and valleys of the concavo-convex structure relatively large as in the shape A of FIG. It can. In the film adopting the shape A, for example, even when it is pulled in a state where a hard layer is coated (for example, vapor deposition or hard coating) on the surface, the hard coating layer can be made less susceptible to cracking. The hard coating layer is loaded because of the above-mentioned local strain. That is, by applying the film having the shape A to, for example, a vapor deposition barrier film, it is possible to give extensibility while suppressing the breakage of the vapor deposition layer. For example, by applying to a vapor deposition barrier film, it is possible to give extensibility while suppressing destruction of the vapor deposition layer. As a vapor deposition film, an alumina, a silica, etc. are mentioned, for example.

  On the other hand, by making the height difference H of the valleys of the concavo-convex structure relatively small as in the shape C of FIG. 6C, conversely, the elongation of the entire film is larger than the local strain as shown in FIG. You can also do it. In the film adopting the shape C, for example, by dispersing microcapsules or the like that react with stress or strain in the film, an application is also possible in which local strain can be intentionally increased with a small amount of elongation. Conceivable. As is apparent from the figure, the shape A shown in FIG. 6 (a) has the highest cross-sectional second moment I shown in the equation (1), and the shape has the lowest cross-sectional second moment I shown in FIG. And the middle is the shape shown in FIG. 6 (b).

(Thickness of film and height of irregularities etc.)
The thickness of the film 1 is preferably 500 μm or less, more preferably 100 μm or less. The thickness of the film does not 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 of the other part.
Moreover, the height difference H of the valleys of the uneven structure is preferably 5 μm to 500 μm. When the height difference H between the mountain and valley is smaller than 5 μm, the effect of bending strength is small, and it is difficult to obtain the adjustment effect of strain. Moreover, when it exceeds 500 micrometers, it will become difficult to attach a concavo-convex structure on manufacture. More preferably, it is better to be in the range of 10 μm to 200 μm. Furthermore, it is more preferable that the thickness of the film 1 is half or less of the height difference H of the valley of the concavo-convex structure. By doing this, better elongation can be obtained.

  In addition, it is preferable that the uneven structure be a periodic structure which is regularly arranged. By not having a random structure, it is easy to obtain intended extensibility, and at the same time, it is possible to simplify the design and manufacture of the concavo-convex structure. However, providing a random uneven structure is optional.

(Anisotropy of second moment of area of this embodiment)
The film of the present embodiment has the characteristic that the moment of inertia of area in the cross section in different directions is different. Thereby, since bending strength differs for every direction, for example, when it uses for the supporting member of a patch, it can respond to the local bending characteristics of human bodies, such as a joint. This anisotropy will be specifically described.

  FIG. 7 shows cross-sectional views of the film of the present embodiment in different directions. FIG. 7A shows a first direction including the direction (first direction) along the ridge line 2a (may be the valley line 3a) with reference to FIG. 2 and the thickness direction (vertical direction) of the film. It is sectional drawing obtained when the film 1 is cut | disconnected in cut surface PL1. On the other hand, in FIG. 7 (b), referring to FIG. 2, the film 1 is cut at a second cut plane PL2 including the direction (second direction) orthogonal to the mountain ridge 2a and the thickness direction of the film. FIG. 6 is a cross-sectional view obtained in In addition, when a mountain ridge is a curve, the tangent is defined as a 1st direction.

For example, in the cross section of FIG. 7 (c) showing one peak (width W) of the film in FIG. 7 (b), the thickness T of the film is 30 μm, the height difference H is 30 μm, Assuming that the prism is a line that connects the axis to the surface of the valley and the back of the peak, the width W is 60 μm.
I _b 4.64.6 × 10 ³ (μm ⁴ )
It becomes.

On the other hand, in the cross section of FIG. 7A, when the thickness of the film is T = 30 μm and the width is W = 60 μm and the moment of inertia of area Ia is obtained, in the case of a flat film of the same thickness,
I _a = WT ³ /12≒1.4×10 ³ (μm ⁴ )
It becomes.
From the above comparison, it is clear that, even with the same film, the second moment of area per unit length varies depending on the direction in which the cross section is taken.

  In addition, the film 1 of this embodiment may be a film 1 having a structure in which the sections are two-dimensionally arranged (also referred to as a "two-dimensional structure"). In the case of a structure consisting of a single section as in FIGS. 1 and 2 (also referred to as “one-dimensional structure”), it is easy to extend in the lateral direction in the figure and in the direction of changing the shape of the concavo-convex structure. It has anisotropic extensibility that it is difficult to extend in the direction intersecting with it (in the direction perpendicular to the sheet). On the other hand, in the case of a two-dimensional structure, it can have both-sided extensibility of extending in either of two directions. In the case of a two-dimensional structure, not only the bending strength but also the tensile strength of the film 1 is enhanced.

(Characteristics of film)
Moreover, since the film 1 of the present embodiment has an effect of stretching when stress is applied, the film 1 is also high in impact resistance, and also high in shock absorption by crushing the uneven structure. Furthermore, since the film 1 of the present embodiment has voids, that is, air layers above and below the film due to the uneven shape of the film 1 when laminated, the film 1 also has a characteristic of high thermal insulation.

(Film material)
The material of the film 1 is preferably a thermoplastic resin or a cured resin (a thermosetting resin, a UV curable resin, etc.). As a thermoplastic resin, for example, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, ethylene vinyl acetate, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, polylactic acid, cyclic polyolefin, polycarbonate, polyamide And polyethylene terephthalate, polybutylene terephthalate, and derivatives thereof. Moreover, as a cured resin, although an epoxy resin, polyurethane, a polyimide, and these derivatives etc. are mentioned, for example, it is not limited to these. These materials may be used alone or two or more of them may be used in combination. Alternatively, a multilayer structure (also referred to as a laminated body) in which a plurality of layers are stacked may be formed.

(Method of producing film)
As a method of producing a film according to the present invention, for example, a method by heat press or a method by extrusion can be used.

  In the first embodiment of the method for producing a film according to the present invention, as shown in FIG. 8, the film 1 and a film (release film) 10 of different material are co-extruded, and a coextruded film (1, 1 in molten state) 10) a seventh step of pressing the cooling roll 8 having a peak-valley shape 8a on the surface against the cooling roll 8 by the nip roll 9 and cooling and solidifying the coextruded film (1, 10) along the cooling roll 8 1 includes an eighth step of forming the film 1 in close contact with the film 10, and a ninth step of peeling the film 10 of a different material from the film 1 after solidification to make the film 1 a single film.

  In FIG. 8A, a step of shaping the valley shape 8a applied to the surface of the cooling roll 8 by co-extrusion onto the film 1 and thereafter a step of cooling the coextruded film along the cooling roll 8 and solidifying it. Indicates

  FIG. 8 (b) shows the cross section of the coextruded film (1, 10) obtained in FIG. 8 (a), and the surface of the film 1 has peaks and valleys corresponding to the peak and valley shape 8a of the surface of the cooling roll 8. The shape is shaped. In addition, the shape of the interface BD between the film 1 and the film 10 of a different material has a valley-like back ridgeline at a position corresponding to the mountain-like surface ridgeline of the surface, and corresponds to the valley-like surface ridgeline of the surface It has a shape with a mountain-like back ridge line at the position where Such a front and back shape is appropriately reproduced when the height difference between the mountain-like surface ridge line and the valley-like surface ridge line is larger than the thickness of the film 1, and the mountain-like surface ridge line and the valley-like surface ridge line In the case where the height difference is smaller than the thickness of the film 1, there is a risk that the back surface can not be made uneven or the front and back surfaces can not properly correspond. In addition, the cooling roll 8 in which the mountain-valley shape 8a was given is producible by the various methods which are well-known. For example, the mountain-valley shape 8a can be produced by a method by laser engraving, a method by cutting, a method by etching, or the like.

  Such coextruded films (1, 10) are peeled off at their respective interfaces BD and separated by the film 1 and the film 10 to form surface ridges and ridges on the surface as shown in FIG. 8 (c). It is possible to obtain a film 1 having a valley-shaped back surface ridgeline at the corresponding position and having a mountain-shaped back surface ridgeline at a position corresponding to the valley-shaped surface ridge line of the surface.

  In another embodiment of the film manufacturing method according to the present invention, as shown in FIG. 9, a cooling roll 8 having a valley shape 8a along the outer periphery and a nip roll having the same valley shape 9a along the outer periphery 9 are aligned (phased) such that the crests of the mountain-shaped peaks (the position most distant from the roll center in the mountain-shaped) and the valley bottom of the valley shape (the positions closest to the roll center in the valley-shaped) coincide. At this time, the gap between the cooling roll 8 and the nip roll 9 is adjusted so that the gap between the rolls is smaller than the thickness of the film to be produced. The manufacturing method of the present film includes a first step of causing the film 1 melted and extruded to enter between the thus adjusted rolls and pressing the film 1 and a second step of cooling and solidifying the film 1 along a cooling roll. Including.

  In FIG. 9 (a), the process of forming the valleys 8a and 9a formed on the surfaces of the cooling roll 8 and the nip roll 9 by extrusion on both surfaces of the film 1 and thereafter the film 1 along the cooling roll 8. Shows a process of cooling and solidifying.

  A peak-valley shape 8 a is provided on the surface of the cooling roll 8, and a peak-valley shape 9 a that is the same as the surface of the cooling roll 8 is provided on the surface of the nip roll 9. When these are incorporated into the extrusion device, it is necessary for the peak and valley shapes of the rolls to be aligned as precisely as possible. Further, it is preferable that the gap between the cooling roll 8 and the nip roll 9 be smaller than the thickness of the film 1 to be manufactured because the shape is accurately formed.

  In order to accurately align the cooling roll 8 and the nip roll 9, the diameters of the cooling roll 8 and the nip roll 9 are accurately matched, and the peripheral speeds of both roll surfaces during extrusion molding are accurately matched (synchronized) There is a need. The material of the nip roll 9 is not particularly limited, but the nip roll 9 is also preferably made of a metal, and more preferably, the material of the nip roll 9 and the material of the cooling roll 8 are the same.

  The film 1 thus obtained (FIG. 9 (b)) has a valley-like back ridgeline at a position corresponding to the mountain-like surface ridgeline of the surface, and the valley-like surface ridgeline of the above-mentioned surface It becomes a shape which has a mountain-like back surface ridgeline in the corresponding position.

  In another embodiment of the method for producing a film of the present invention, as shown in FIG. 10, when the melting point of the film is Tm, the film 1 is heated at (Tm-20) ° C. or more and (Tm + 10) ° C. An upper surface flat mold 11 having a valley (valley shape) 11a on the surface (lower surface) and a lower flat plate mold 12 having the same valley shape 12a on the front surface (upper surface) The position (phase) of the mold adjusted in this way so that (the position farthest from the back surface of the mountain shape of the surface) and the bottom of the valley shape (the position closest to the back surface of the valley shape of the surface) coincide. In the meantime, a fourth step of passing the heated film 1 and pressing it, a fifth step of cooling and solidifying the film 1 in a state of pressing between the dies, and a sixth step of peeling the film 1 from the die Including.

  FIGS. 10 (a) and 10 (b) schematically show the process of molding by hot pressing. The top and bottom flat molds 11 and 12 are provided with mountain-valley shapes 11a and 12a on their surfaces in advance, so that their peak and valley shapes match as closely as possible in the embossing direction (vertical direction). Are aligned with In this state, the film 1 heated at (Tm-20) ° C. or more and (Tm + 10) ° C. or less is inserted, and pressed with the molds 11 and 12. As a method of heating the film 1, there are a heater, a heating roll and the like, and the method is not particularly limited. When the heating temperature is less than (Tm-20) ° C., the temperature is too low to achieve the desired shape reshape, and when the heating temperature exceeds (Tm + 10) ° C., The film is softened and flows, and the film resin adheres to a roll, a conveyor, or the like at the time of transportation or the like, and the molding can not be properly performed. In addition, it is preferable that the surface of the upper and lower flat plate mold be coated with a fluorine-based release agent or a silicone-based release agent in order to improve the releasability from the film.

  The film 1 is cooled and solidified in a pressed state, and then peeled off from the upper and lower flat plate molds, thereby forming valleys at positions corresponding to the surface ridges of the surface as shown in FIG. 10C. It has a back surface ridgeline, and has a mountain-like back surface ridgeline at a position corresponding to the valley-like surface ridgeline of the front surface.

(Laminate)
The film 1 may be a single layer as shown in FIG. 1, and further, as shown in FIG. 11, a plurality of films 1 may be laminated to form a laminate. The lamination of the film may be three or more layers. Moreover, it can also be set as the laminated body which laminated functional layers, such as a vapor deposition layer, a hard-coat layer, and a reflection prevention layer, with the film 1 by a post process.

  In addition, as shown in FIGS. 12 (a), (b) and (c), a laminate 5 in which another functional layer 4 is laminated on the film 1 can also be used. Here, according to the embodiment of FIG. 12A, another functional layer 4 is directly attached to the film 1 to form a laminate 5. On the other hand, according to the embodiment of FIG. 12 (b), another functional layer 4 is attached to the film 1 via the adhesive layer (or adhesive layer) 6 to form a laminate 5. At this time, a gap is maintained between the film 1 and the adhesive layer (or pressure-sensitive adhesive layer) 6. Further, as shown in FIG. 12C, another functional layer 4 is attached to the film 1 via the adhesive layer (or pressure-sensitive adhesive layer) 6 to form a laminate 5, but the film 1 and the adhesive layer ( Or it can also laminate | stack in the state which a space | gap is not maintained between the adhesive layer 6). Here, another functional layer 4 is preferably a functional layer having a specific function, such as an ink layer, a deposition barrier layer, or a coating barrier layer.

(Use of film)
For example, it is conceivable to use a film 1 having high bending strength and high extensibility or a laminate using it as a packaging material and a barrier film. Moreover, although the application of utilizing as a support body of patches, such as a compress, is also considered, a use is not restricted to these. The backing of the patch, which is an application example, is required to have resistance, non-adsorption or barrier properties to drugs and additives contained in the patch, and it is desirable to be extensible. All these requirements can be satisfied by adding a concavo-convex structure to the material having high chemical resistance, non-adsorption property and barrier property to make the film 1 having high extensibility. Examples of the material having high chemical resistance, non-adsorption property and barrier property include cyclic polyolefin, polyethylene terephthalate, ethylene-vinyl alcohol copolymer and the like.

(Another embodiment of the film)
FIGS. 13 to 17 are surface views showing an embodiment in the case of having a plurality of sections in the series of films 1, in which a mountain ridge line is indicated by a solid line and a valley ridge line is indicated by a dotted line. In FIG. 13, the film 1 has 16 sections 1A each surrounded by an edge Fr, and from one edge Fr (also referred to as "edge") of each section 1A, the other edge opposite to this is To the end, the mountain ridge 2a and the valley ridge 2b extend in different directions. Although not shown, the same applies to mountain ridges and valley ridges on the back side. In the film with extensibility, the film stretches during processing and has a surface on which stable film formation is difficult, but such arrangement enables stable film formation during molding and processing, and the final product is cut for each section By performing punching or punching, a patch support film 1 can be provided that extends in a desired direction. There may not be clear boundaries between adjacent sections 1A. Also, the number of sections 1A present on a film suitable for a series of patch supports is arbitrary. When a plurality of sections are used without being separated, high bending strength can be secured in any direction by making the sectional second moment high in different directions in each section.

  The film 1 shown in FIG. 14 is a two-section patch support film surrounded by the edges Fr. This is effective, for example, when half of the film is fixed and only the other half is desired to be stretched, and high bending strength can be secured in both the longitudinal and lateral directions. When the film 1 is applied to, for example, a patch, when the patch is applied to the skin, it is possible to first attach the non-stretching half of the film to the skin and fix it, and extend the other half.

  In the film 1 shown in FIG. 15, from the one edge of each section 1A surrounded by the edge Fr to the other edge crossing it, the angled (45 degrees) angled ridgeline 2a and valley ridgeline 2b extends straight. The other configuration is the same as that of the film 1 shown in FIG. The angle between the mountain ridge 2 a and the valley ridge 2 b is arbitrary, and may be different for each section.

  The film 1 shown in FIG. 16 is a strip-shaped film 1 having a single section, and from the one side edge Fr to the other side edge Fr, the mountain ridge 2a and the valley ridge 2b extend in an arc. It exists. This is a film which has high rigidity in the width direction and is hard to bend. The other configuration is the same as that of the embodiment described above.

  FIG. 17 is a cross-sectional view showing still another embodiment. In the film 1 shown in FIG. 17, the mountain ridge line groups 2a1, 2a2, 2a3 and the valley ridge line groups 2b1, 2b2, 2b3 are provided side by side on the surface 2, and they are opposed to each other to form valley ridge lines on the back surface 3. The groups 3a1, 3a2, 3a3 and the mountain ridge line groups 3b1, 3b2, 3b3 are provided side by side. These ridges are periodically repeated.

  Although the embodiments (including the manufacturing method) of the present invention have been exemplified above, it goes without saying that the present invention is not limited to the embodiments. Moreover, it is arbitrary to use combining the above embodiment.

  Hereinafter, although the example which the present inventors made is described in detail, the present invention is not limited only to the following examples.

Example 1
The material of film 1 is Ingeo 3052D (trade name) which is polylactic acid (PLA) manufactured by NatureWorks, and as the material of which co-extrusion is different, Novatec LD LC600A (a low density polyethylene (LDPE) manufactured by Japan Polyethylene Corporation) Product name). The thickness of the film 1 (PLA) was 8 μm, and the thickness of LDPE was 30 μm. Moreover, the peak-and-valley shape of the cooling roll surface was made into the shape which arranged the waveform cross-sectional shape periodically. The pitch of the corrugated uneven structure is 50 μm, and the height difference is 25 μm.
These two materials are co-extruded by the extruder shown in FIG. 8, arranged so that the PLA is in contact with the surface shape of the cooling roll, pressed by a rubber nip roll, and cooled along the cooling roll to solidify the coextruded film did. Thereafter, the solidified coextruded film was peeled off at the PLA / LDPE interface to obtain a PLA film having a bellows structure of a corrugated cross section shown in FIG. 18 (b).

(Example 2)
In Example 1, the peak-and-valley shape of the surface of the cooling roll is a shape in which trapezoidal cross-sectional shapes are periodically arranged. This obtained the PLA film which has the bellows structure of the trapezoid cross section shown in FIG.18 (c). The trapezoidal cross-sectional shape has an upper side 61 μm, a lower side 68 μm, a height difference 31 μm, and a pitch of 140 μm. Other than that, the sample was produced by the same method as Example 1.

(Comparative example 1)
A sample was produced in the same manner as in Example 1 except that a mirror roll having no unevenness was used on the surface of the cooling roll in Example 1. This obtained the PLA film of the flat cross section shown to Fig.18 (a).

(Example 3)
In Example 1, TOPAS 8007 (trade name), which is a cyclic olefin copolymer (COC) manufactured by Polyplastics Co., Ltd., is used as a material of the film 1, and polystyrene (PS Japan Co., Ltd.) is used as a different coextrusion material. PS) HF77 (trade name). Moreover, the peak-and-valley shape of the cooling roll surface was made into the shape which arranged the waveform cross-sectional shape periodically. As a result, a COC film having a bellows structure with a corrugated cross section shown in FIG. 18 (b) was obtained. The pitch of the corrugated uneven structure is 500 μm, and the height difference is 250 μm. The film thickness was 125 μm.

(Comparative example 2)
In Example 3, a sample was produced in the same manner as in Example 3 except that a mirror surface roll without unevenness was used on the cooling roll surface. Thereby, the COC film of the flat cross section shown to Fig.18 (a) was obtained.

(Example 4)
In Example 1, Novatec PP FB3B (trade name), which is polypropylene (PP) manufactured by Japan Polypropylene Corporation, is used as the material of the film 1, and low density polyethylene (LDPE) manufactured by Japan Polyethylene Corporation is used as the different coextrusion material. The product was named Novatec LD LC600A (trade name). Moreover, the peak-and-valley shape of the cooling roll surface was made into the shape which arranged the trapezoidal cross-sectional shape periodically. As a result, a PP film having a bellows structure of trapezoidal cross section shown in FIG. 18 (c) was obtained. The trapezoidal cross-sectional shape has an upper side 61 μm, a lower side 68 μm, a height difference 31 μm, and a pitch of 140 μm. The film thickness was 28 μm.

(Comparative example 3)
In Example 4, a sample was produced in the same manner as in Example 4 except that a mirror surface roll without irregularities was used on the cooling roll surface. This obtained the PP film of the flat cross section shown to Fig.18 (a).

(Example 5)
Soanol D2908 (trade name) which is an ethylene-vinyl alcohol copolymer (EVOH) manufactured by Japan Synthetic Chemical Industry Co., Ltd. is used as a material of film 1, and low density polyethylene manufactured by Japan Polyethylene Corporation is used as a different material for coextrusion. Novatec LD LC 701 (trade name) which is (LDPE). Moreover, the peak-and-valley shape of the cooling roll surface was made into the shape which arranged the trapezoidal cross-sectional shape periodically. As a result, an EVOH film having a bellows structure with a trapezoidal cross section shown in FIG. 18C was obtained. The trapezoidal cross-sectional shape has an upper side of 205 μm, a lower side of 224 μm, a height difference of 60 μm, and a pitch of 255 μm. The film thickness was 30 μm.

(Comparative example 4)
In Example 5, a sample was produced in the same manner as in Example 5 except that a mirror surface roll without irregularities was used on the cooling roll surface. Thus, an EVOH film of flat cross section shown in FIG. 18 (a) was obtained.

(Elongation evaluation method)
In order to evaluate the extensibility performance of the film 1 in each Example and Comparative Example, a tensile test evaluation was performed. Elongation evaluation is based on JIS K 7127: 1999, using a tensile tester manufactured by Shimadzu Corporation (AGS-500NX), while applying tensile force from the state of zero until breakage of the film, while timely stretching the film It carried out by asking for. Regarding the measurement conditions, the sample width was 15 mm, the distance between chucks was 50 mm, and the tensile speed was 100 mm / min. About evaluation, it was set as "(circle)", when the elongation rate until it starts necking while a film material starts plastic deformation while being 20% or more, and it was set as "x" when it is less than it.

(Bending strength evaluation method)
In order to evaluate the bending strength performance of the film 1 in each Example and a comparative example, it evaluated using the Toyo Seiki Seisaku-sho make loop stiffness tester. The compression speed was 3.3 mm / sec, the sample width was 25 mm, and the loop length was 85 mm. About evaluation, when bending strength ratio is 2 times or more compared with the flat film of the same thickness and the same thickness, it was set as "(circle)", and when it was less than it, it was set as "x."

(Evaluation method of film formation stability and formability)
The film produced by the extrusion apparatus was observed with a microscope to evaluate whether a uniform film could be stably produced and whether a concavo-convex structure could be formed with high accuracy.

  Table 1 shows a list of conditions and evaluation results in each example and comparative example.

(Evaluation results)
As can be seen from Table 1, in Examples 1 to 5, the film 1 had a bellows structure, so that the extensibility or bending strength showed good results.
On the other hand, in Comparative Examples 1 to 4, the film 1 had a flat structure, and as a result, the result was not obtained for the extensibility and the bending strength beyond the properties possessed by the material itself.
In addition, about film forming stability, all of the Example and the comparative example have satisfy | filled the reference | standard, and regarding the shapeability, all of the Example had satisfy | filled the reference | standard.

DESCRIPTION OF SYMBOLS 1 film 1A section 2 front surface 2a, 3b mountain ridgeline 3 back surface 2b, 3a valley ridgeline 4 another functional layer 5 laminated body 7 T die 8 cooling roll 9 nip roll 10 film of different material 11 top flat plate mold 12 bottom flat plate Type P pitch H height difference T film thickness Fr edge

Claims (14)

The front and back of the film are divided into at least one or more compartments,
The compartments have an edge dividing the compartments,
In at least one of the compartments,
In the surface of the section, it has mountain-shaped surface ridges and valley-shaped surface ridges extending between the edge and the edge;
In the back surface of the section, a valley-shaped back surface ridgeline is provided at a position corresponding to a mountain-shaped surface surface ridge line of the surface, and a mountain-shaped back surface ridgeline is provided at a position corresponding to the valley-shaped surface surface ridge line ,
The height difference between the mountain-like surface ridge line and the valley-like surface ridge line is larger than the thickness of the film,
The thickness of the film is 500 μm or less,
The moment of inertia of area per unit length of the first cut surface when the film is cut along the first direction along the surface ridgeline and the thickness direction of the film is orthogonal to the first direction A film characterized by being smaller than a moment of inertia of area per unit length of a second cut surface when the film is cut along a second direction and a thickness direction of the film. The film according to claim 1, wherein the mountain-shaped surface ridge lines and the valley-shaped surface ridge lines are alternately arranged. The film according to claim 1 or 2, wherein the group of the plurality of mountain-shaped surface ridges and the group of the plurality of valley-shaped surface ridges are alternately formed. The film according to any one of claims 1 to 3, wherein the mountain-like surface ridge line and the valley-like surface ridge line are straight lines. The film according to any one of claims 1 to 4, wherein the mountain-like surface ridge line and the valley-like surface ridge line are curves respectively. The film according to any one of claims 1 to 5, wherein a plurality of the sections are provided and in contact with each other.   The film according to any one of claims 1 to 6, wherein the height difference is 5 μm to 500 μm. The film according to any one of claims 1 to 7, wherein the mountain-shaped surface ridge line and the valley-shaped surface ridge line are arranged at equal intervals. The film according to any one of claims 1 to 7, wherein an interval between the mountain-like surface ridge line and the valley-like surface ridge line is random. The laminated body which further laminated | stacked the functional layer on the at least one surface of the film as described in any one of Claims 1-9.   A laminate obtained by laminating a plurality of the films according to any one of claims 1 to 9. A method of producing a film according to any one of claims 1 to 9,
The phases are adjusted so that the cooling roll whose valley and valley shape is applied along the outer periphery and the nip roll on which the same valley and valley shape is applied along the outer periphery match the peak and valley bottom of the valley and valley shape with each other A first step of causing a material of the melt extruded film to enter and press between the cooling roll and the nip roll while setting the gap between the cooling roll and the nip roll to be smaller than the thickness of the film When,
And a second step of forming the film by cooling and solidifying the material of the film along the cooling roll. A method of producing a film according to any one of claims 1 to 9,
A third step of heating the material of the film at (Tm-20) ° C. or more and (Tm + 10) ° C. or less, where Tm is the melting point of the material of the film;
Adjust the phase of the upper surface flat mold with the valley shape on the lower surface and the lower flat mold with the same valley shape on the upper surface so that the peak and valley bottom of the peak shape match the valley direction in the embossing direction. And a fourth step of inserting and pressing the material of the heated film between the upper surface flat mold and the lower flat surface mold;
A fifth step of cooling and solidifying the material of the film while pressing between the dies;
And a sixth step of peeling the film from a mold. A method of producing a film according to any one of claims 1 to 9,
A seventh step of co-extruding the material of the film and the material of the peeling film different from the material of the film and pressing the melting two materials against a cooling roll having a valley shape on its surface by a nip roll ,
An eighth step of forming the film and the peeling film in close contact with each other by cooling and solidifying the coextruded two materials along a cooling roll;
And a ninth step of separating the peeling film from the film and separating the film.