JP2021133441A - Method of manufacturing powder - Google Patents

Abstract

To provide a manufacturing method that enables manufacture of powder in which the proportion of thin film pieces having a constant shape along a crack is high.SOLUTION: A method of manufacturing powder includes: a step (1) of forming a crack 100C, which splits a thin film 110 into small pieces assuming the same shape when seen from its thickness direction, and reaches a position deeper than a surface 120U on the thin film side of a base material layer 120, in a multilayer film 100 including the base material layer 120 and the thin film 110 arranged on the outermost side; and a step (2) of obtaining the powder, which includes the small pieces of the thin film 110, by separating the small pieces of the thin film 110 from the base material layer 120 of the multilayer film 100 formed with the crack 100C.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for producing a powder.

As the pigment of the ink, a powder made of a thin film piece formed of a thin film formed of a metal, a resin, or the like may be used.
In order to produce a resin thin film piece, a release layer is formed on the base film, a resin thin film is formed on the release layer, cracks are formed in the resin thin film, and then the base film is bent at a sharp angle. A method of peeling off a resin thin film as a thin film piece is known (see Patent Document 1).
Further, a resin thin film is formed on the base film, a member having an uneven shape is pressed against the resin thin film, cracks are formed in the resin thin film, and a fluid is sprayed on the cracked resin thin film to spray the resin thin film. A method of peeling off the plastic is also known (see Patent Document 2).

Special Fairness 07-08024A Gazette International Publication No. 2019/189246

The ink is used for printing such as screen printing, gravure printing, intaglio printing, and offset printing. The powder contained in the ink preferably has a sharper peak in the particle size distribution in order to improve the texture of the printed matter.
In order for the powder to have a sharp peak in the particle size distribution, it is preferable that the shapes of the thin film pieces contained in the powder are as uniform as possible.
Further, in order to confirm the authenticity of the printed matter, for example, the powder contained in the ink used in the printed matter may be observed with a microscope. In this case, if it can be confirmed that the shapes of the thin film pieces contained in the powder are uniform, the authenticity of the printed matter can be easily determined, and the security performance of the printed matter can be improved.
Therefore, it is preferable that the thin film pieces contained in the powder have the same shape as possible.
However, when a powder composed of thin film pieces is produced by a conventional technique, the thin film is peeled from the base film without being divided along the cracks, and as a result, the powder composed of the thin film pieces has a constant shape along the cracks. A considerable amount of thin film pieces having a shape different from that of the above may be mixed.
Therefore, there is a need for a manufacturing method capable of producing a powder having a large proportion of thin film pieces having a constant shape along the cracks.

As a result of diligent studies to solve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by forming predetermined cracks in the multilayer film, and completed the present invention.
That is, the present invention provides the following.

[1] A crack in a multi-layer film containing a base material layer and a thin film arranged on the outermost side, which divides the thin film into small pieces having the same shape when viewed from the thickness direction of the base material layer. The step (1) of forming a crack that reaches a position deeper than the surface on the thin film side, and
A method for producing a powder, which comprises a step (2) of peeling a small piece of the thin film from the base material layer of the multi-layer film on which the crack is formed to obtain a powder containing the small piece of the thin film.
[2] The method for producing a powder according to [1], wherein the major axis of the small piece is 150 μm or less.
[3] The powder according to [1] or [2], wherein in the step (1), a member having an uneven shape is pressed against the thin film side of the multilayer film to form the cracks. Production method.
[4] The method for producing a powder according to [3], wherein the pressing is performed in a state where the multilayer film is supported by a support member having a surface hardness of D40 or more.
[5] The method for producing a powder according to [4], wherein the pressure for pressing the member having the uneven shape is 0.5 MPa or more.
[6] The production of the powder according to any one of [1] to [5], wherein the step (2) includes a step (2a) of spraying a fluid onto the cracked multilayer film. Method.
[7] The method for producing a powder according to any one of [1] to [6], wherein the thickness of the base material layer is 12 μm or more and 250 μm or less.
[8] In the step (1), the cracks are formed so that the shape of the small pieces is a triangle, a quadrangle, or a hexagon when viewed from the thickness direction of the thin film [1] to [7]. The method for producing a powder according to any one of the above.

According to the present invention, it is possible to provide a production method capable of producing a powder having a large proportion of thin film pieces having a constant shape along a crack.

FIG. 1 is a cross-sectional view showing an example of a multilayer film used in the step (1) according to the embodiment. FIG. 2 is a schematic plan view of the surface of the double glazing film on which cracks are formed on the thin film side according to the embodiment as viewed from the thickness direction of the double glazing film. FIG. 3 is a cross-sectional view schematically showing the cut surface III-III of FIG. FIG. 4 is a schematic plan view of the surface of the multilayer film on the thin film side in which cracks are formed according to the embodiment, as viewed from the thickness direction of the multilayer film. FIG. 5 is a cross-sectional view schematically showing the VV cut surface of FIG. FIG. 6 is a perspective view schematically showing an example of a member having an uneven shape that can be used in the powder manufacturing method of one embodiment. FIG. 7 is a perspective view schematically showing the member having the uneven shape shown in FIG. FIG. 8 is a plan view schematically showing a state in which the member of FIG. 7 is cut along the X1-X1 line and developed. FIG. 9 is a partial cross-sectional view taken along the line Y1-Y1 of FIG. FIG. 10 is a perspective view schematically showing an example of a member having an uneven shape that can be used in the powder manufacturing method of one embodiment. FIG. 11 is a perspective view schematically showing the member having the uneven shape shown in FIG. FIG. 12 is a plan view schematically showing a state in which the member of FIG. 11 is cut along the X2-X2 line and developed. FIG. 13 is a partial cross-sectional view taken along the line Y2-Y2 of FIG.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, the "long" film means a film having a length of 5 times or more, preferably 10 times or more, and specifically a roll. A film that has a length that allows it to be rolled up and stored or transported. The upper limit of the length of the film is not particularly limited, and may be, for example, 100,000 times or less with respect to the width.

In the following description, the term "(meth) acrylic" includes "acrylic", "methacryl" and combinations thereof.

In the following description, the directions of the elements are "parallel" and "vertical", unless otherwise specified, within a range that does not impair the effect of the present invention, for example, within a range of ± 3 °, ± 2 °, or ± 1 °. May include the error of.

[1. Outline of powder manufacturing method]
In the method for producing a powder according to an embodiment of the present invention, a multi-layer film containing a base material layer and a thin film arranged on the outermost side is divided into small pieces having the same shape when viewed from the thickness direction thereof. The thin film is formed from the step (1) of forming a crack, which is a crack to be formed and reaches a position deeper than the surface of the base material layer on the thin film side, and the base material layer of the multilayer film in which the crack is formed. The step (2) of peeling off the small pieces of the thin film to obtain a powder containing the small pieces of the thin film is included. This makes it possible to produce a powder having a large proportion of thin film pieces having a constant shape along the cracks.

[2. Process (1)]
In the step (1), a crack is formed in a multi-layer film including a base material layer and a thin film arranged on the outermost side, and the thin film is divided into small pieces having the same shape when viewed from the thickness direction of the thin film. A crack is formed that reaches a position deeper than the surface of the material layer on the thin film side.

[2.1. Multi-layer film]
The multilayer film used in the step (1) includes a base material layer and a thin film. The thin film is arranged on the outermost side of the multilayer film. Here, "arranged on the outermost side" means that the thin film is arranged on the outermost side in the thickness direction of the multilayer film. Therefore, the surface of the thin film is exposed on one surface of the multilayer film. The multilayer film may include an arbitrary layer between the thin film and the base material layer.
The multi-layer film is preferably long in order to form cracks efficiently.
FIG. 1 is a cross-sectional view showing an example of a multilayer film used in the step (1) according to the embodiment. As shown in FIG. 1, the multilayer film 10 includes a base material layer 12 and a thin film 11 provided directly on the base material layer 12.

(Base layer)
The base material layer is preferably long in order to efficiently form a thin film.
Examples of the material forming the base material layer are not particularly limited, and examples thereof include a resin containing a polymer, paper, and a metal, and a resin containing a polymer is preferable because it is excellent in flexibility and mechanical strength. ..
Examples of the polymer contained in the resin capable of forming the base material layer include a cellulose-based polymer (eg, triacetyl cellulose); a polymer containing an alicyclic structure (eg, a cycloolefin polymer); and a polyester (eg, polyester). Examples include polyethylene terephthalates); acrylic polymers (eg, poly (meth) acrylic acid, poly (meth) acrylic acid ester, polyacrylonitrile); and polycarbonate; The resin capable of forming the base material layer may contain the polymer alone or as a combination of two or more kinds. Further, the polymer may be a homopolymer or a copolymer. The resin may contain any additive in addition to the polymer.

Examples of polymers containing an alicyclic structure include (1) norbornene-based polymers, (2) monocyclic cyclic olefin polymers, (3) cyclic conjugated diene polymers, and (4) vinyl alicyclic hydrocarbons. Examples thereof include hydrogen polymers and hydrides thereof. Among these, norbornene-based polymers and hydrides thereof are preferable from the viewpoint of transparency and moldability.

Examples of the norbornene-based polymer include a ring-opening polymer of a monomer having a norbornene structure and a hydride thereof; an addition polymer of a monomer having a norbornene structure and a hydride thereof. Examples of ring-opening polymers of monomers having a norbornene structure include a ring-opening copolymer of one type of monomer having a norbornene structure and ring-opening of two or more types of monomers having a norbornene structure. Examples thereof include a copolymer and a ring-opening copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Further, examples of the addition polymer of the monomer having a norbornene structure are an addition homopolymer of one kind of monomer having a norbornene structure and an addition copolymer of two or more kinds of monomers having a norbornene structure. , And an addition copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Examples of these polymers include polymers disclosed in JP-A-2002-321302.

Preferable specific examples of the norbornene-based polymer and hydrides thereof include "Zeonor" manufactured by Zeon Corporation; "Arton" manufactured by JSR Corporation; and "TOPAS" manufactured by TOPAS ADVANCED POLYMERS.

The thickness of the base material layer is preferably 12 μm or more, more preferably 25 μm or more, further preferably 50 μm or more, preferably 250 μm or less, more preferably 200 μm or less, still more preferably 188 μm or less. When the thickness of the base material layer is at least the above lower limit value, the mechanical strength of the base material layer can be made more excellent. When the thickness of the base material layer is not more than the upper limit value, the flexibility of the base material layer can be improved and the handling at the time of manufacturing can be facilitated.

The base material layer may have a single-layer structure or a multi-layer structure.

When the base material layer has a multi-layer structure, it is preferable that each layer contained in the base material layer has a peeling strength to the extent that the base material layers do not peel off from each other in the steps (1) and (2).
The base material layer preferably has a single layer structure.

The surface of the base material layer may be subjected to a treatment such as a rubbing treatment or a corona treatment.
The base material layer may be an unstretched unstretched layer or a stretched layer.

The multilayer film may be a film composed of only a base material layer and a thin film, and may include an arbitrary layer in addition to the base material layer and the thin film. For example, when a liquid crystal composition is used as a composition for forming a thin film, the multilayer film may have an alignment film between the base material layer and the thin film from the viewpoint of satisfactorily aligning the liquid crystal composition. good. The alignment film can be formed of, for example, a resin containing a polymer such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamideimide, polyetherimide, or polyamide. In addition, one of these polymers may be used alone, or two or more of these polymers may be used in combination at any ratio. The alignment film can be produced by applying a solution containing the above-mentioned polymer, drying, and applying a rubbing treatment.

(Thin film)
The thin film may have either a single-layer structure or a multi-layer structure. Further, the thin film may be either a conductor or a dielectric. Further, the thin film may be either an inorganic film or an organic film. Examples of thin films include metal films such as aluminum and silver; dielectric multilayer films made of dielectrics such as titanium oxide, silicon oxide, niobium oxide, tantalum oxide and magnesium fluoride; and resin films. Be done.
Examples of resin materials for forming a resin film include photocurable liquid crystal compositions, acrylic resins, polystyrenes, polyesters, polyamides, polyvinyl chlorides, polyvinyl acetates, and cellulose-based polymers (eg, triacetyl cellulose). , Polystyrene, polyurethane, polyolefin, alicyclic structure-containing polymer, epoxy resin, melamine resin, phenol resin, and combinations thereof. The polymer that can be contained in the resin material may be a homopolymer or a copolymer. In addition to the polymer, the resin material may contain any additive such as a curing agent and an antioxidant.

The thickness of the thin film can be appropriately set according to the material of the thin film, the purpose of use of the powder, etc., but from the viewpoint of ensuring the reflectance of the thin film, it is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably. Is 1 μm or more, preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less. By setting the thickness of the thin film to the upper limit or less, the obtained powder can be suitably used for inks corresponding to printing layers having various thicknesses.

As the thin film, for example, a film made of a cured product cured by using a photocurable liquid crystal composition as a composition containing a resin can be used. That is, as the resin forming the thin film, for example, a cured product of a photocurable liquid crystal composition can be used. Here, the material referred to as a "liquid crystal composition" for convenience includes not only a mixture of two or more kinds of substances but also a material composed of a single substance.

Further, as the thin film, for example, a cholesteric resin layer may be used. The cholesteric resin layer is a resin layer having cholesteric regularity. The cholesteric regularity of the resin layer having cholesteric regularity is that the molecular axes are aligned in a certain direction on one plane, but on the next plane that overlaps with the molecular axes, the directions of the molecular axes deviate at a slight angle, and further. The structure is such that the angle of the next plane is further shifted, and the angle of the molecular axis in the plane is shifted (twisted) as it sequentially passes through the planes arranged in an overlapping manner. That is, when the molecules in the layer have cholesteric regularity, the molecules are aligned in the resin layer in a manner of forming a layer of a large number of molecules. In a certain layer A among the layers of such a large number of molecules, the molecules are aligned so that the axis of the molecule is in a certain direction, and in the adjacent layer B, the molecules are displaced at an angle with the direction in the layer A. The molecules are aligned in the direction, and in the layer C adjacent to the molecule, the molecules are aligned in a direction further deviated from the direction in the layer B at an angle. In this way, in the layers of a large number of molecules, the angles of the axes of the molecules are continuously deviated, and a structure in which the molecules are twisted is formed. The structure in which the direction of the molecular axis is twisted in this way becomes an optically chiral structure.

The cholesteric resin layer usually has a circularly polarized light separation function. That is, it has the property of transmitting one of the right-handed circularly polarized light and the left-handed circularly polarized light and reflecting a part or all of the other circularly polarized light. Further, the reflection in the cholesteric resin layer reflects the circularly polarized light while maintaining its chirality.

When the cholesteric resin layer as described above is used as the thin film, the proportion of the thin film pieces having a constant shape, which are powders composed of small pieces of the resin film utilizing the circular polarization separation function, is determined by the production method of the present embodiment. A large amount of powder can be produced.

The thin film can be formed by any method depending on the material of the thin film and the like. For example, the thin film can be formed by a vapor deposition method, a sputtering method, a coating method, or the like. Here, examples of coating methods include die coating method, curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, and print coating method. A gravure coating method and a gap coating method can be mentioned.

[2.2. Crack formation]
(crack)
The crack formed in the step (1) divides the thin film contained in the multilayer film into small pieces having the same shape when viewed from the thickness direction. Further, the cracks are formed so as to reach a position deeper than the surface of the base material layer on the thin film side. Further, the cracks are formed so as to reach a position deeper than the surface of the base material layer on the thin film side on the entire surface of the multilayer film.

The shape of the small piece viewed from the thickness direction of the thin film is not particularly limited, and examples thereof include polygons such as triangles, quadrangles, and hexagons, crosses, and circles, and are preferably triangles, quadrangles, or hexagons.

The major axis of the small piece seen from the thickness direction of the thin film is preferably 250 μm or less, more preferably 200 μm or less, still more preferably 175 μm or less, still more preferably 150 μm or less, from the viewpoint of suppressing clogging of the printing plate with ink. From the viewpoint of improving the visibility of the print layer formed by the ink, it is usually larger than 0 μm, preferably 10 μm or more. Here, the major axis refers to the longest distance among the parallel lines when a plurality of parallel lines are drawn so as to be in contact with the contour of the small piece.

Hereinafter, an example of a crack formed in the step (1) will be described.
FIG. 2 is a schematic plan view of the surface of the double glazing film on which cracks are formed on the thin film side according to the embodiment as viewed from the thickness direction of the double glazing film. FIG. 3 is a cross-sectional view schematically showing the cut surface III-III of FIG.

As shown in FIG. 2, the multilayer film 100 is formed with lattice-shaped cracks 100C. The crack 100C has a plurality of linear notches 100C1 extending downward to the right at an angle of θ1 with respect to the width direction WD of the multilayer film 100, and a linear notch 100C1 extending downward to the upper right at an angle of θ2. It is composed of a plurality of notches 100C2. Here, if the angle in the clockwise direction is positive and the angle in the counterclockwise direction is negative with respect to the width direction WD of the multilayer film 100 in FIG. 2, θ1 is 45 ° and θ2 is −. It is 45 °.

In the present embodiment, the distance P11 between adjacent notches 100C1 is substantially the same as the distance P12 between adjacent notches 100C2. Here, substantially the same means that P12 is 90% or more and 110% or less of P11. The lattice-shaped crack 100C having the plurality of notches 100C1 and the plurality of notches 100C2 divides the outermost thin film of the multilayer film 100 into a plurality of small pieces 101 which are substantially square. The plurality of small pieces 101 have sides having lengths corresponding to the intervals P11 and the intervals P12, and in the present embodiment, the length of one side of the plurality of small pieces 101 is P11.

As shown in FIG. 3, the multilayer film 100 includes a base material layer 120 and a thin film 110 formed directly on the base material layer 120. The depth 100Cd of the crack 100C is the distance from the surface 110U on the thin film 110 side of the multilayer film 100 to the tip 100Ct of the crack 100C. The depth 100Cd of the crack 100C is larger than the thickness 110T of the thin film 110. Therefore, the tip 100Ct of the crack 100C reaches a position deeper than the surface 120U on the thin film 110 side of the base material layer 120.

FIG. 4 is a schematic plan view of the surface of the double glazing film on the thin film side in which cracks are formed according to another embodiment, as viewed from the thickness direction of the double glazing film. FIG. 5 is a cross-sectional view schematically showing the VV cut surface of FIG.

As shown in FIG. 4, honeycomb-shaped cracks 200C are formed in the multilayer film 200. The honeycomb-shaped crack 200C divides the outermost thin film of the multilayer film 200 into a plurality of small pieces 201 having a substantially regular hexagon.
As shown in FIG. 5, the multilayer film 200 includes a base material layer 220 and a thin film 210 formed directly on the base material layer 220. Also in this embodiment, the tip 200Ct of the crack 200C reaches a position deeper than the surface 220U on the thin film 210 side of the base material layer 220.

In yet another embodiment, the multilayer film may have continuous triangular cracks when viewed from the thickness direction of the multilayer film.

(Rhagades formation method)
The cracks can be formed, for example, by pressing a member having an uneven shape on the thin film side of the multilayer film. More specifically, in a state where the multilayer film is supported by the support member, the multilayer film is sandwiched between the support member and the member having the concave-convex shape, and the member having the concave-convex shape is pressed to form a crack. Can be done.

As the member having the uneven shape, a member having a convex portion on the surface corresponding to the shape of the crack seen from the thickness direction of the multilayer film can be used. For example, when the shape of the cracks seen from the thickness direction of the multilayer film is a grid pattern, a member having a grid pattern convex portion on the surface can be used. When the shape of the cracks in the thickness direction of the multilayer film is honeycomb-shaped, a member having a honeycomb-shaped convex portion on the surface can be used.

Moreover, you may use a plurality of members as a member which has a concavo-convex shape. For example, a member having a convex portion corresponding to a part of the crack on the surface and a member having a convex portion corresponding to another part of the crack on the surface may be used. For example, when the cracks are in a grid pattern and the thin film is divided into squares when viewed from the thickness direction thereof, the uneven shape having the convex portions corresponding to the notches in one direction forming the cracks on the surface. The crack is formed by pressing the first member having a rugged shape and the second member having a concavo-convex shape having a convex portion corresponding to a notch in another direction on the surface, which constitutes the crack, against the multilayer film. It may be formed.

Further, the same member having an uneven shape may be pressed against the multilayer film a plurality of times in different arrangements to form cracks.

A member having an uneven shape may be formed into a cylindrical shape to continuously form cracks in the multilayer film.

As a member having an uneven shape, a material having a strength that does not cause damage even when the multilayer film is pressed and capable of forming an uneven structure can be adopted. Examples of such materials include carbon steel and stainless steel. Further, the member having an uneven shape may have one layer or two or more layers of a multilayer film on the surface for the purpose of increasing corrosion resistance, strength, thermal conductivity and the like. Such a film is not particularly limited, and examples thereof include a plating film of nickel, nickel phosphorus, silicon, copper and the like, a film formed by ceramic spraying, and the like. For example, a heater, a heat medium, a heating means using dielectric heating, induction heating, or the like, a static eliminator for static electricity countermeasures, a ground, or the like may be attached to the member having an uneven shape.

The member having an uneven shape can be manufactured by any conventionally known method. For example, a member having a desired uneven shape can be formed by cutting a member such as a cylindrical metal roll with a cutting tool such as a diamond tool or processing with a laser processing device.

The pressure when the member having the uneven shape is pressed toward the thin film side of the multilayer film is preferably 0.5 MPa or more, more preferably 1 MPa or more, further preferably 5 MPa or more, preferably 100 MPa or less, more preferably. Is 75 MPa or less. By setting the pressure to the lower limit value or more, cracks having a sufficient depth can be formed in the multilayer film, and by setting the pressure to the upper limit value or less, the breakage of the multilayer film can be suppressed. When a member having one or more uneven shapes is pressed against the multilayer film a plurality of times in order to form a crack in the multilayer film, the multiple pressings may be the same or different. Preferably, the multiple presses are performed at the same pressure.

The support member usually has a support surface that supports a surface opposite to the side of the thin film contained in the multilayer film. The hardness of the support surface that supports the surface of the multilayer film is preferably D40 or more, more preferably D60 or more, still more preferably D70 or more, preferably D99 or less, more preferably D97 or less, still more preferably D95 or less. be. Here, the hardness is a value measured by a durometer (type D) according to JIS K-6253. By setting the hardness of the support surface of the support member within the above range, cracks having an appropriate depth can be easily formed in the multilayer film. As the support member, a material having a strength that does not cause damage even when the multilayer film is pressed by a member having an uneven shape can be adopted. Examples of the material of the surface of the support member include rubber and resin.

The shape of the support member may be any shape (for example, roll shape, flat plate shape) depending on, for example, a method of transporting the double glazing film and a method of pressing a member having an uneven shape against the double glazing film. The support member is preferably in a roll shape because cracks can be continuously formed in the multi-layer film by using a long multi-layer film.

Hereinafter, an example of a member having an uneven shape and a step (1) using the member will be described.

FIG. 6 is a perspective view schematically showing an example of a member having an uneven shape that can be used in the powder manufacturing method of the present embodiment. FIG. 7 is a perspective view schematically showing the member having the uneven shape shown in FIG. FIG. 8 is a plan view schematically showing a state in which the member of FIG. 7 is cut along the X1-X1 line and developed. FIG. 9 is a partial cross-sectional view taken along the line Y1-Y1 of FIG. FIG. 10 is a perspective view schematically showing an example of a member having an uneven shape that can be used in the powder manufacturing method of the present embodiment. FIG. 11 is a perspective view schematically showing the member having the uneven shape shown in FIG. FIG. 12 is a plan view schematically showing a state in which the member of FIG. 11 is cut along the X2-X2 line and developed. FIG. 13 is a partial cross-sectional view taken along the line Y2-Y2 of FIG.

As shown in FIG. 6, the member 1110 having an uneven shape is arranged so as to be in contact with the surface of the multilayer film 10 on the thin film 11 side, and presses the multilayer film 10. Further, as shown in FIG. 10, the member 1115 having an uneven shape is arranged so as to be in contact with the surface of the multilayer film 10 on the thin film 11 side, and presses the multilayer film 10. The order of pressing the multilayer film 10 by the member 1110 having an uneven shape and pressing the multilayer film 10 by the member 1115 having an uneven shape is not particularly limited. For example, the multilayer film 10 is pressed by the member 1110 having an uneven shape. It may be pressed and then pressed by the member 1115 having the uneven shape, or the multilayer film 10 may be pressed by the member 1115 having the uneven shape and then pressed by the member 1110 having the uneven shape.

As shown in FIG. 6, the outer surface (the surface in contact with the multilayer film 10) of the member 1110 having an uneven shape is provided with irregularities. As shown in FIG. 10, the outer surface of the member 1115 having an uneven shape is also provided with irregularities. The members 1110 and 1115 having an uneven shape have a cylindrical shape as shown in FIGS. 6 and 10, and can be rotationally moved on the multilayer film 10.

The support member 1120 arranged on the surface of the multilayer film 10 on the base material layer 12 side is a member that sandwiches and presses the multilayer film 10 together with the member 1110 having an uneven shape.
The support member 1125 arranged on the surface of the multilayer film 10 on the base material layer 12 side is a member that sandwiches and presses the multilayer film 10 together with the member 1115 having an uneven shape. The support member 1120 and the support member 1125 are each cylindrical, and can be rotationally moved under the multilayer film 10.

Of the surfaces of the multilayer film 10, the surface (upper surface in the drawing) on the side that comes into contact with the members 1110 and 1115 having an uneven shape is the surface on which the thin film 11 is formed. When the multilayer film 10 is sandwiched between the member 1110 having an uneven shape and the support member 1120, the convex portion 1110T of the member 1110 having an uneven shape comes into contact with the thin film 11. By pressing the multilayer film 10 in a state of being sandwiched between the member 1110 having the uneven shape and the support member 1120, the convex portion 1110T of the member 1110 having the uneven shape penetrates into the thin film 11 and the base material layer 12 and cracks. The notch 100C1 constituting 100C is formed. Further, when the multilayer film 10 is sandwiched between the member 1115 having the uneven shape and the support member 1125, the convex portion 1115T of the member 1115 having the uneven shape comes into contact with the thin film 11. By pressing the multilayer film 10 in a state of being sandwiched between the member 1115 having the uneven shape and the support member 1125, the convex portion 1115T of the member 1115 having the uneven shape penetrates into the thin film 11 and the base material layer 12 and cracks. Notches 100C2 constituting 100C are formed. In this way, the multilayer film 10 in which the crack 100C is formed is obtained (see FIGS. 2 and 3).

An uneven shape is formed on the outer surface of the member 1110 having an uneven shape. As shown in FIG. 8, the concave-convex shape has convex portions 1110T and concave portions 1110D extending in a direction inclined by an angle θx with respect to the direction indicated by L1 alternately in a direction perpendicular to the forming direction of the convex portions 1110T. It is a repeatedly formed shape. θx is not particularly limited and may be, for example, 45 °. As shown in FIG. 8, the concavo-convex shape of the member 1110 having the concavo-convex shape is a shape in which straight lines descending to the right are lined up when viewed from the paper surface. The distance between two adjacent convex portions 1110T (distance Q1 between the convex portion 1110T1 and the convex portion 1110T2 shown in FIG. 9) can be appropriately set. In FIGS. 7 and 8, the ends 1111, 1112 are the ends of the member 1110 having an uneven shape.

As shown in FIG. 9, the convex portion 1110T may have a mountain shape having an acute-angled apex 1110t in a cross-sectional view. In FIG. 9, θ11 is the angle of the apex of the convex portion. It is preferable that θ11 is small, but it can be, for example, 10 ° or more, 20 ° or more, or 30 ° or more, and can be, for example, 90 ° or less, 80 ° or less, 70 ° or less, or 60 ° or less. The apex shape of the convex portion 1110T may be a rounded shape or a chamfered shape as long as it is possible to form cracks in the thin film and the base material layer.

An uneven shape is formed on the outer surface of the member 1115 having an uneven shape. As shown in FIG. 12, the concave-convex shape has convex portions 1115T and concave portions 1115D extending in a direction inclined by an angle θy with respect to the direction indicated by L2, alternately in a direction perpendicular to the forming direction of the convex portions 1115T. It is a repeatedly formed shape. θy is not particularly limited and may be, for example, 45 °. As shown in FIG. 12, the uneven shape of the member 1115 having the uneven shape is a shape in which straight lines rising to the right are lined up when viewed from the paper surface. The distance between two adjacent convex portions 1115T (distance Q2 between the convex portion 1115T1 and the convex portion 1115T2 shown in FIG. 13) can be appropriately set. In FIGS. 11 and 12, the ends 1116 and 1117 are the ends of the member 1115 having a concavo-convex shape.

As shown in FIG. 13, the convex portion 1115T may have a mountain shape having an acute-angled apex 1115t in a cross-sectional view. In FIG. 13, θ12 is the angle of the apex of the convex portion 1115T. It is preferable that θ12 is small, but it can be, for example, 10 ° or more, 20 ° or more, or 30 ° or more, and can be, for example, 90 ° or less, 80 ° or less, 70 ° or less, or 60 ° or less. The apex shape of the convex portion 1115T may be a rounded shape or a chamfered shape as long as it is possible to form cracks in the thin film and the base material layer.
By performing the step (1), cracks are formed in the multilayer film (for example, as shown in FIGS. 3 and 5, cracks 100C or 200C are formed in the multilayer film 10). .. The cracked multi-layer film (eg, multi-layer films 100, 200) is subjected to step (2).

The shape of the crack reflects the shape of the convex portion of the member having the uneven shape. For example, when a member 1110 having a concave-convex shape having a developed shape shown in FIG. 8 is arranged and pressed so that the L1 direction in FIG. 8 is parallel to the longitudinal direction of the double glazing film, the length of the double glazing film 10 is long. Notches can be formed diagonally with respect to the direction. Next, when the member 1115 having the uneven shape of the developed shape shown in FIG. 12 is arranged and pressed so that the L2 direction of FIG. 12 is parallel to the longitudinal direction of the multilayer film, it is as shown in FIG. A grid-like crack 100C can be formed. In FIG. 2, the downward-sloping linear notch 100C1 reflects the shape of the convex portion of the member 1110 having the concave-convex shape, and the upward-sloping linear notch 100C2 is the convex portion of the member 1115 having the concave-convex shape. It reflects the shape of.

[3. Process (2)]
In the step (2), the small pieces of the thin film are peeled off from the base material layer of the multi-layer film in which the cracks are formed to obtain a powder containing the small pieces of the thin film.

The method of peeling the small pieces of the thin film from the base material layer is not particularly limited, and for example, (1) a method of sliding a multi-layer film having cracks formed on the blade to peel off the small pieces; (2) water. , A method of spraying a fluid such as air on a multi-layer film in which cracks are formed to peel off small pieces; (3) It is difficult to dissolve a thin film (for example, a cholesteric resin layer) A multi-layer film in which cracks are formed is immersed in a solvent (for example, water) that dissolves a layer (for example, an alignment film formed of polyvinyl alcohol) existing between the layers, and a thin film is formed from the base material layer. Method of peeling off small pieces; (4) By sticking the thin film side of the multi-layer film in which cracks are formed to the base film for transfer using a water-soluble adhesive, and then peeling the base layer from the multi-layer film. , A method of peeling a small piece of a thin film from a base material layer; a combination thereof;
In the method (4) above, a laminate having a normal (transfer base film) / (water-soluble adhesive layer) / (thin film in which cracks are formed) layer structure can be obtained. A powder containing small pieces of a thin film can be obtained by removing the layer of the water-soluble adhesive from the laminate by immersing the laminate in water at an appropriate temperature or the like.

When the cracked multilayer film is long, the powder can be efficiently produced by continuously performing the peeling step.

For example, the step (2) may include a step (2a) of spraying a fluid on the cracked multilayer film.
In step (2a), the fluid is sprayed onto the cracked side (that is, the thin film side) of the cracked multilayer film. A known fluid discharge device can be used as the spraying device. The pressure of the fluid discharged from the fluid discharge device can be appropriately adjusted according to the density of the fluid, the peel strength between the base material layer and the thin film, and the like. The discharge pressure is not particularly limited, but is preferably 5 MPa or more, more preferably 10 MPa or more, preferably 50 MPa or less, and more preferably 35 MPa or less.

The step (2) may include a step (2b) in which the small pieces of the thin film are peeled off and then the small pieces are passed through a sieve.
For example, after the step (2a) of spraying the fluid on the cracked multilayer film, the small pieces peeled from the base material layer may be passed through a filter having a predetermined opening.
Further, the step (2) may include a step (2c) of collecting the small pieces after peeling off the small pieces of the thin film.
For example, after the step (2a) of spraying the fluid onto the cracked multilayer film, the small pieces peeled from the base material layer are guided to the recovery path together with the fluid, and the small pieces are collected by the recovery device to collect the small pieces. You may obtain the body powder. As the collector, for example, a cyclone type separator and various filters can be used.

[4. Powder characteristics]
The powder obtained by the production method of the present embodiment has a large proportion of thin film pieces having a constant shape along the cracks. The ratio can be evaluated by, for example, the following method.
The powder is a 10% by weight aqueous dispersion. The aqueous dispersion is dropped onto the slide to evaporate the water content, and the powder (thin film piece) is attached to the slide. Observe the part of the preparation to which the thin film piece is attached with a microscope. Within a 1 mm square area, the number of thin film pieces (A) having a fixed shape and the number (B) of non-standard thin film pieces are counted, and the percentage X with respect to the number (A) of the number (B) is calculated according to the following formula. Ask. X = B / A x 100 (%)
The smaller the percentage X, the higher the proportion of thin film pieces having a constant shape along the crack.

The powder has a percentage X of preferably 5% or less, more preferably 4% or less, still more preferably 3% or less, and preferably 0%, but 0% or more or 1% or more. It may be.

[5. Use of powder]
The powder produced by the production method of the present embodiment has a large proportion of thin film pieces having a constant shape along the cracks. Therefore, it is possible to obtain a printed matter having a good texture by using an ink containing powder. In addition, the authenticity of printed matter using ink containing powder can be easily determined. Therefore, the powder can be suitably used as a material for ink.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, "%" and "part" representing quantities are based on weight unless otherwise specified. Further, the operations described below were performed under normal temperature and pressure conditions unless otherwise specified.

[evaluation]
(Evaluation of crack condition)
The cross section of the multi-layer film of each cracked example was observed with a scanning electron microscope, and it was evaluated whether or not the crack reached a position deeper than the surface of the base material layer of the multi-layer film. Observation was performed on a cross section having a length in the plane direction of 500 μm at an arbitrary position of the multilayer film. In the observation range, when the crack reaches a position deeper than the surface of the base layer of the double glazing, the crack reaches a position deeper than the surface of the base layer of the double glazing on the entire surface of the double glazing. Was regarded as. In the observation range, some cracks do not reach deeper than the surface of the base layer of the double glazing, or all cracks do not reach deeper than the surface of the base layer of the double glazing. In this case, the cracks did not reach a position deeper than the surface of the base material layer of the double glazing of the double glazing.

(Evaluation of shape consistency of powder (thin film piece))
The powder (thin film piece) obtained in each example was used as a 10% by weight aqueous dispersion. Next, the aqueous dispersion was dropped onto the slide to evaporate the water content, and the thin film pieces were attached to the slide. The part of the preparation to which the thin film piece was attached was observed with an optical microscope. Within a 1 mm square area, the number of standard thin film pieces (A) and the number of non-standard thin film pieces (B) corresponding to the unevenness of the member having the uneven shape in each example are counted, and according to the following formula. The percentage X with respect to the number (A) of the number (B) was determined. X = B / A x 100 (%)
The smaller the percentage X, the higher the proportion of thin film pieces having a constant shape along the crack. That is, the shape consistency is high.
The shape consistency of the thin film pieces was evaluated according to the following criteria.
"Good": X ≤ 5%
"Defective": 5% <X or A = 0

[Example 1]
(1-1. Preparation of photocurable liquid crystal composition)
18.1 parts of BASF's photopolymerizable liquid crystal compound "Pariocolor LC242", 1.3 parts of BASF's "LC756" as a surfactant, and 0 of Ciba Japan's "Irgacure OXEO2" as a photopolymerization initiator. A photocurable liquid crystal composition was prepared by mixing 6 parts, 0.02 part of "Futergent 209F" manufactured by Neos Co., Ltd. as a surfactant, and 80 parts of cyclopentanone.

(1-2. Manufacture of long multi-layer film)
As a base film, a long cycloolefin polymer (COP) film (“ZF16-100” manufactured by Zeon Corporation; thickness 100 μm) was prepared. This base film was attached to the feeding portion of the film transport device, and the following operations were performed while transporting the base film in the longitudinal direction. First, a rubbing treatment was performed in the longitudinal direction parallel to the transport direction. Next, the liquid crystal composition prepared in (1-1) was applied to the surface subjected to the rubbing treatment using a die coater. As a result, a film of the uncured liquid crystal composition was formed on one side of the base film.

The obtained film of the liquid crystal composition is oriented at 100 ° C. for 5 minutes, and then the film of the liquid crystal composition is ^{irradiated with ultraviolet rays of 800 mJ / cm 2} in a nitrogen atmosphere to complete the film of the liquid crystal composition. Hardened to. As a result, a multi-layer film having a resin thin film having a thickness of 3.5 μm was obtained on one side of the long base film. The multi-layer film has a layer structure of (base film as a base layer) / (resin thin film). The resin thin film had a function as a cholesteric resin layer.

(1-3. Manufacture of members (rolls) having an uneven shape)
A metal roll made of stainless steel with electroless nickel plating (NiP plating) on the surface was prepared. The surface of the plated roll was cut with a diamond bite (apical angle 60 °) to obtain roll A and roll B having a plurality of convex portions.
In the roll A, the plurality of convex portions are extended so that the convex portions extend in a direction of 45 ° upward to the right with respect to the straight line on the roll peripheral surface parallel to the roll axis, and the pitch of the convex portions is set. It was formed so that the angle of the apex of the convex portion was 60 ° in the cross section perpendicular to the direction in which the convex portion was further extended so as to be 50 μm.
In the roll B, the plurality of convex portions are extended so that the convex portions extend in a direction forming an angle of 45 ° upward to the left with respect to the straight line on the roll peripheral surface parallel to the roll axis, and the pitch of the convex portions is set. It was formed so that the angle of the apex of the convex portion was 60 ° in the cross section perpendicular to the direction in which the convex portion was further extended so as to be 50 μm.

(1-4. Step (1): Rhagades formation step)
The roll A produced in (1-3) is pressed against the multilayer film produced in (1-2) from the resin thin film side (press pressure 10 MPa), and then the roll B is pressed (press pressure 10 MPa). Cracks were formed in the multi-layer film. At that time, the side opposite to the resin thin film of the multilayer film (base film side, backup roll side) was supported by the backup roll. As the backup roll, a roll having a surface hardness of D70 was used. Here, the hardness is a value measured by a durometer (type D) according to JIS K-6253. The same applies hereinafter. As a result, the resin thin film of the multilayer film was divided into small square pieces (major axis 70 μm) having a side of 50 μm when viewed from the thickness direction of the resin thin film.

The state of cracks in the multilayer film after the roll A and the roll B were pressed was evaluated by the above method. As a result, it was found that cracks were formed on the entire surface of the multilayer film to a position deeper than the surface of the base film included in the multilayer film.

(1-5. Step (2): Powder manufacturing step)
Next, water was sprayed from the side of the resin thin film on the cracked multilayer film at a discharge pressure of 60 MPa to peel off small pieces of the resin thin film from the base film.

Next, the peeled small pieces of the resin thin film are passed through a sieve having a nominal opening of 53 μm, and the small pieces under the sieve are collected by a filter collector (3M, all polypropylene filter), and the powder containing the small pieces of the resin thin film is collected. I got a body. The shape consistency of the obtained powder was evaluated by the above method. The results are shown in the table below.

[Example 2]
(2-1 to 2-2)
As the base film, a long triacetyl cellulose film (“KC6UY” manufactured by Konica Minolta Co., Ltd .; thickness 60 μm) was used. Except for the above items, a multilayer film was produced in the same manner as in Examples 1 (1-1) to (1-2).

(2-3. Manufacture of members (rolls) having an uneven shape)
A metal roll similar to (1-3) of Example 1 was prepared, and the surface of the plated roll was cut with a diamond bite (apical angle 60 °) to obtain a roll C having a plurality of convex portions. ..
In the roll C, the convex portions extend in a direction of 45 ° upward to the left with respect to the straight line on the roll peripheral surface parallel to the roll axis, and the pitch of the convex portions is 100 μm. It was formed so as to be.

(2-4. Step (1): Rhagades formation step)
-Roll C was used instead of roll B.
The press pressures of roll A and roll C were set to 8 MPa, respectively.
-As a backup roll, a roll having a surface hardness of D90 was used.
Except for the above items, the same operation as in (1-4) of Example 1 was carried out to form cracks in the multilayer film. As a result, the resin thin film of the multilayer film was divided into rectangular small pieces (major axis 112 μm) having a size of 50 μm × 100 μm when viewed from the thickness direction of the resin thin film.

The state of cracks in the multilayer film after the roll A and the roll C were pressed was evaluated by the above method. As a result, it was found that cracks were formed on the entire surface of the multilayer film to a position deeper than the surface of the base film included in the multilayer film.

(2-5. Step (2): Powder manufacturing process)
The opening of the sieve through which the small pieces of the peeled resin thin film are passed was changed from the nominal opening of 53 μm to the nominal opening of 106 μm. Except for the above items, a powder was obtained in the same manner as in (1-5) of Example 1, and the obtained powder was evaluated. The results are shown in the table below.

[Example 3]
(3-1 to 3-2)
As a multi-layer film, a polyethylene terephthalate (PET) film (“VMPET1519” manufactured by Toray Film Processing Co., Ltd.) on which aluminum was vapor-deposited to a thickness of 12 μm was prepared. The multi-layer film has a layer structure of (aluminum film as a thin film) / (PET film as a base material layer).

(3-3. Manufacture of members (rolls) having an uneven shape)
A metal roll similar to (1-3) of Example 1 was prepared. A dent was formed on the surface of the plated roll with an ultrashort pulse laser (dimple processing) to obtain a roll D.
The roll D has a continuous hexagonal convex portion having a major axis of 50 μm and a side of 25 μm.

(3-4. Step (1): Rhagades forming step)
-Roll D was used instead of roll A.
-The double glazing was not pressed by the roll B.
The press pressure of the roll D was set to 12 MPa.
-As a backup roll, a roll having a surface hardness of D88 was used.
Except for the above items, the same operation as in (1-4) of Example 1 was carried out to form cracks in the multilayer film. As a result, the aluminum film of the multilayer film was divided into hexagonal small pieces having a major axis of 50 μm and a side of 25 μm when viewed from the thickness direction of the film.

The state of cracks in the multilayer film after the roll D was pressed was evaluated by the above method. As a result, it was found that cracks were formed on the entire surface of the multilayer film to a position deeper than the surface of the base film included in the multilayer film.

(3-5. Step (2): Powder manufacturing process)
A powder was obtained in the same manner as in (1-5) of Example 1, and the obtained powder was evaluated. The results are shown in the table below.

[Comparative Example 1]
-The backup roll was changed to a roll formed by coating stainless steel with silicon rubber having a hardness of D20.
The press pressure of the roll A and the roll B was set to 70 MPa, respectively.
Except for the above items, the same operation as in Example 1 was carried out to obtain a powder, and the obtained powder was evaluated. The results are shown in the table below.
Further, in the multilayer film after the roll A and the roll B were pressed, the state of cracks was evaluated by the above method. As a result, in the observation range, there were no cracks reaching a position deeper than the surface of the base film included in the multilayer film.

In the table below, the abbreviations have the following meanings.
"Cholesteric resin layer": Layer of cured product of liquid crystal composition "Al film": Deposited aluminum film "COP": Cycloolefin polymer film "TAC": Triacetyl cellulose film "PET": Polyethylene terephthalate film

From the above results, in the production method of Comparative Example 1 in which the cracks that reach a position deeper than the surface of the base material layer on the thin film side are not formed, the shape consistency of the obtained powder is poor. On the other hand, in the production method of the example in which the cracks reaching a position deeper than the surface of the base material layer on the thin film side are formed, the shape consistency of the obtained powder is good.
From the above results, it can be seen that the powder production method according to the present invention can produce a powder having a large proportion of thin film pieces having a desired shape.

10 Multi-layer film 11 Thin film 12 Base material layer 100 Multi-layer film 100C Crack 100C1 Notch 100C2 Notch 100Cd Depth 100Ct Tip 101 Small piece 110 Thin film 110T Thickness 110U Surface 120 Base layer 120U Surface 200 Multi-layer film 200C Thin film 220 Base material layer 220U Surface 1110 Concavo-convex shape member 1110T Convex part 1110T1 Convex part 1110T2 Convex part 1110t Peak 1110D Concave part 1111 End part 1112 End part 1115 Member with uneven shape 1115T Convex part 1115T Convex part 1115T Recess 1116 End 1117 End 1120 Support member 1125 Support member

Claims (8)

A crack that divides the thin film into small pieces having the same shape when viewed from the thickness direction of the multilayer film including the base material layer and the thin film arranged on the outermost side, and the thin film side of the base material layer. The step of forming a crack (1), which reaches a position deeper than the surface of the
A method for producing a powder, which comprises a step (2) of peeling a small piece of the thin film from the base material layer of the multi-layer film on which the crack is formed to obtain a powder containing the small piece of the thin film. The method for producing a powder according to claim 1, wherein the major axis of the small piece is 150 μm or less. The method for producing a powder according to claim 1 or 2, wherein in the step (1), a member having an uneven shape is pressed against the thin film side of the multilayer film to form the cracks. The method for producing a powder according to claim 3, wherein the pressing is performed in a state where the multilayer film is supported by a support member having a surface hardness of D40 or more. The method for producing a powder according to claim 4, wherein the pressure for pressing the member having the uneven shape is 0.5 MPa or more. The method for producing a powder according to any one of claims 1 to 5, wherein the step (2) includes a step (2a) of spraying a fluid onto the cracked multilayer film. The method for producing a powder according to any one of claims 1 to 6, wherein the thickness of the base material layer is 12 μm or more and 250 μm or less. Any one of claims 1 to 7, wherein in the step (1), the crack is formed so that the shape of the small piece becomes a triangle, a quadrangle, or a hexagon when viewed from the thickness direction of the thin film. The method for producing a powder according to.

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