WO2021209841A1

WO2021209841A1 - Flocked film and method of manufacture of thereof

Info

Publication number: WO2021209841A1
Application number: PCT/IB2021/052389
Authority: WO
Inventors: Hiroki ARAZOE; Yuji Hiroshige; Shinsuke KONDO; Naoyuki Toriumi; Tasuku Nakayama
Original assignee: 3M Innovative Properties Company
Priority date: 2020-04-16
Filing date: 2021-03-23
Publication date: 2021-10-21

Abstract

A flocked film includes a base film having a first major surface and a second major surface opposite to the first major surface. A plurality of microstructures are disposed on the first major surface. Each microstructure includes a top portion and at least one side surface extending between the top portion and the first major surface. An adhesive layer is disposed on at least the first major surface of the base film and the at least one side surface of each microstructure. A plurality of fibers are adhered to the adhesive layer. One or more fibers from the plurality of fibers are adhered to the at least one side surface of one or more microstructures.

Description

FLOCKED FILM AND METHOD OF MANUFACTURE OF THEREOF

Technical Field

The present disclosure relates generally to films, and more specifically to flocked films and methods of manufacturing flocked films.

Background

Flocked surfaces are generally used in various applications, for example, as artificial leather, such as velour, suede or nubuck.

Typically, flocked surfaces are prepared using electrostatic flocking. Electrostatic flocking generally requires high voltages in the preparation process to raise staple fibers on substrates. In addition, various conductive treatments on the stable fibers are also required to raise the staple fibers by an electric field.

Further, sprinkling staple fibers on a substrate may often result in a low-density area of flocked surface. Such flocked surfaces may not provide desired visual and tactile sensation.

It would therefore be desirable to manufacture flocked surfaces, without applying any electric field and conductive treatment on the staple fibers, with improved visual and tactile sensation.

Summary

Generally, the present disclosure relates to flocked films. The present disclosure also relates to structural details of a flocked film as well as a manufacturing method of such a flocked film.

In one embodiment of the present disclosure, a flocked film is provided. The flocked film includes a base film having a first major surface and a second major surface opposite to the first major surface. The base film includes a plurality of microstructures disposed on the first major surface. Each microstructure includes a top portion and at least one side surface extending between the top portion and the first major surface. The flocked film further includes an adhesive layer disposed on at least the first major surface of the base film and the at least one side surface of each microstructure. The flocked film includes a plurality of fibers adhered to the adhesive layer. One or more fibers from the plurality of fibers are adhered to the at least one side surface of one or more microstructures In some embodiments, the adhesive layer is further disposed on the top portion of each microstructure. One or more fibers from the plurality of fibers are adhered to the top portion of one or more microstructures.

In some embodiments, one or more fibers from the plurality of fibers are inclined obliquely with respect to a normal to the first major surface.

In some embodiments, two or more fibers from the plurality of fibers are inclined obliquely with respect to each other.

In some embodiments, each fiber extends between two ends. The two ends of one or more fibers from the plurality of fibers are free.

In some embodiments, a length of each fiber is equal to or greater than a length of the at least one side surface of each microstructure.

In some embodiments, the length of each fiber is from about 1 time to about 3.5 times the length of the at least one side surface of each microstructure.

In some embodiments, a diameter of each fiber is from about 8 micrometers to about 50 micrometers.

In some embodiments, each fiber is conductive or non-conductive.

In some embodiments, each fiber includes carbon.

In some embodiments, the flocked film further includes a plurality of grooves alternating with the plurality of microstructures. A bottom surface of each groove is defined by a portion of the first major surface extending between the at least one side surfaces of adjacent microstructures.

In some embodiments, a main surface of the base film is defined by the top portion and the at least one side surface of each microstructure and the bottom surface of each groove. The adhesive layer is disposed on the main surface of the base film.

In some embodiments, one or more fibers from the plurality of fibers are adhered to the top portion of one or more microstructures, and one or more fibers from the plurality of fibers are adhered to the bottom surface of one or more grooves.

In some embodiments, a height of each microstructure is from about 10 micrometers to about 1000 micrometers, and a maximum width of each microstructure is from about 10 micrometers to about 1000 micrometers.

In some embodiments, a minimum width of the bottom surface of each groove is from about 0 micrometer to about 500 micrometers.

In some embodiments, a distance between adjacent microstructures is from about 10 micrometer to about 1000 micrometers. In some embodiments, the minimum width of the bottom surface of each groove is from about 0 % to about 50% of the distance between adjacent microstructures.

In some embodiments, the top portion of each microstructure is at least one of a surface, an edge and a vertex.

In another embodiment, a method of manufacturing a flocked film is provided. The method includes providing a base film including a first major surface, a second major surface opposite to the first major surface, and a plurality of microstructures disposed on the first major surface. Each microstructure includes a top portion and at least one side surface extending between the top portion and the first major surface. The method includes providing an adhesive layer on at least the first major surface of the base film and the at least one side surface of each microstructure. The method includes depositing a plurality of fibers on the plurality of microstructures and the first major surface of the base film. The method further includes rubbing the plurality of fibers onto the plurality of microstructures and the first major surface such that one or more fibers from the plurality of fibers are adhered to the at least one side surface of one or more microstructures.

In some embodiments, providing the adhesive layer further includes providing the adhesive layer on the top portion of each microstructure such that one or more fibers from the plurality of fibers are adhered to the top portion of one or more microstructures.

In some embodiments, depositing the plurality of fibers on the plurality of microstructures and the first major surface of the base film does not include applying an electric field.

The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exhaustive list.

Brief Description of the Drawings

The disclosure may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. FIG. l is a schematic cross-sectional view of a flocked film as per present disclosure;

FIGS. 2A-2D illustrate schematic cross-sectional views of different types of microstructures that can be used to manufacture a flocked film;

FIGS 3 A-3D illustrate schematic perspective views of different types of microstructures that can be used to manufacture a flocked film;

FIGS. 4A-4C illustrate steps of manufacturing a flocked film as per present disclosure;

FIG. 5 is a flowchart illustrating a method of manufacturing a flocked film; and

FIGS. 6A-6E illustrate an exemplary preparation of a flocked film.

Detailed Description

In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

As recited herein, all numbers should be considered modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.

As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within +/- 20 % for quantifiable properties).

The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/- 10% for quantifiable properties) but again without requiring absolute precision or a perfect match. Terms such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match.

The present disclosure relates to a flocked film including a base film having a first major surface and a second major surface opposite to the first major surface. The base film includes a plurality of microstructures disposed on the first major surface. The flocked film includes an adhesive layer disposed on at least the first major surface of the base film and at least one side surface of the microstructure. The flocked film further includes a plurality of fibers adhered to the adhesive layer. Such a flocked film may be manufactured by rubbing the plurality of fibers onto the plurality of microstructures, without applying any electric field and conductive treatment on the plurality of fibers. Further, the flocked film may also provide improved tactile sensation and reduction in light reflection. The reduction in light reflection may further provide inconspicuous parts having low concentration of fibers.

FIG. 1 illustrates a flocked film 100 according to the present disclosure. The flocked film 100 may be applied to decorative products. The flocked film 100 may also function as a sensor based on triboelectric effect. The flocked film 100 may be used in various other applications and the examples provided herein are not limiting in any manner.

The flocked film 100 includes a base film 110. In some embodiments, the base film 110 includes a polymerizable resin, a thermoplastic resin, or any other suitable material. In some embodiments, the polymerizable resin may include a combination of a first polymerizable component and a second polymerizable component selected from (meth)acrylate monomers, (meth)acrylate oligomers, and mixtures thereof. As used herein, “monomer” or “oligomer” is any substance that can be converted into a polymer. The term “(meth)acrylate” refers to both acrylate and methacrylate compounds. In some cases, the polymerizable composition may include a (meth)acrylated urethane oligomer,

(meth)acrylated epoxy oligomer, (meth)acrylated polyester oligomer, a (meth)acrylated phenolic oligomer, a (meth)acrylated acrylic oligomer, and mixtures thereof. In some embodiments, the thermoplastic resin may include polyethylene terephthalate, polycarbonate, polyether sulfone, polyether imide, polyacrylate, polymethyl methacrylate, polystyrene, polyvinyl acetate, polycaprolactone, phenoxy resins, and various polyesters. The base film 110 has a first major surface 112 and a second major surface 114 opposite to the first major surface 112. The base film 110 further includes a plurality of microstructures 120 disposed on the first major surface 112. Each microstructure 120 includes a top portion 122 and at least one side surface 124 extending between the top portion 122 and the first major surface 112. The top portion 122 of each microstructure 120 is at least one of a surface, an edge and a vertex. The plurality of microstructures 120 may have any suitable shape as per application requirements. In the illustrated embodiment of FIG. 1, each microstructure 120 has a rectangular shape. The top portion 122 of each microstructure 120 is a substantially planar surface. Each microstructure 120 includes a pair of side surfaces 124 extending from opposing edges of the top portion 122. Each of the side surfaces 124 may be substantially planar. In some embodiments, an angle between the top portion 122 and each side surface 124 is substantially 90 degrees. In some other embodiments, the angle between the top portion 122 and each side surface 124 is from about 80 degrees to about 110 degrees. In some embodiments, the flocked film 100 further includes a plurality of grooves 170 alternating with the plurality of microstructures 120. A bottom surface 172 of each groove 170 is defined by a portion of the first major surface 112 extending between the at least one side surfaces 124 of adjacent microstructures 120. The bottom surface 172 of each groove 170 is substantially planar. Each groove 170 is a U-shaped groove defined by the side surfaces 124 of adjacent microstructures 120 and the bottom surface 172 extending between the side surfaces 124.

In some embodiments, a height “H” (shown in FIG. 4 A) of each microstructure 120 is from about 10 micrometers to about 1000 micrometers. In some embodiments, the height “H” is about 20 micrometers to about 900 micrometers. In some embodiments, a maximum width of each microstructure 120 is from about 10 micrometers to about 1000 micrometers. In some embodiments, a minimum width “W” (shown in FIG. 4 A) of the bottom surface 172 of each groove 170 is from about 0 micrometer to about 500 micrometers. In some other embodiments, the minimum width “W” is about 1 micrometer to about 450 micrometers. In some embodiments, a distance “D” (shown in FIG. 4A) between adjacent microstructures 120 is from about 10 micrometer to about 1000 micrometers. The height “H” of each microstructure 120 and the minimum width “W” of the bottom surface 172 of each groove 170 may vary based on application requirements. Further, the distance “D” between adjacent microstructures 120 may also vary based on application requirements. The distance “D” between adjacent microstructures 120 may also correspond to a pitch of the microstructures 120. In some embodiments, the minimum width “W” is from about 0% to about 50% of the distance “D” between adjacent microstructures 120.

The flocked film 100 includes an adhesive layer 130. The adhesive layer 130 is disposed on at least the first major surface 112 of the base film 110 and the at least one side surface 124 of each microstructure 120. In some embodiments, the adhesive layer 130 is further disposed on the top portion 122 of each microstructure 120. The adhesive layer 130 may include any type of an adhesive material, such as an acrylate, a pressure sensitive adhesive, a stretch release adhesive, an adhesive foam etc. A thickness of the adhesive layer 130 may vary as per application requirements. The adhesive layer 130 may be continuous or discontinuous based on application requirements.

In some embodiments, the adhesive layer 130 may have a matte surface with low gloss. In some embodiments, the adhesive layer 130 may include an optically clear adhesive (OCA). In some other embodiments, the adhesive layer 130 may have a similar color as the base film 110. The present disclosure is not limited by type of adhesive in any manner. The flocked film 100 further includes a plurality of fibers 140 adhered to the adhesive layer 130. In some embodiments, the plurality of fibers 140 may include staple fibers. In some embodiments, the plurality of fibers 140 may be natural fibers, such as cotton, wool, jute etc. In some other embodiments, the plurality of fibers 140 may be artificial fibers, such as nylon, polyethylene terephthalate (PET), viscose rayon, and so forth. In some embodiments, each fiber 140 may be conductive. The conductive fibers may allow dust prevention and antistatic property. In some other embodiments, each fiber 140 may be non- conductive. The non-conductive fibers may not need an electrostatic coating. In some embodiments, each fiber 140 may include carbon. In some embodiments, each fiber 140 may include activated carbon thereby providing deodorizing. The plurality of fibers 140 may have similar color as the base film 110.

One or more fibers 140a from the plurality of fibers 140 are adhered to the at least one side surface 124 of one or more microstructures 120 via the adhesive layer 130. In some embodiments, one or more fibers 140b from the plurality of fibers 140 are adhered to the top portion 122 of one or more microstructures 120 via the adhesive layer 130. In some embodiments, one or more fibers 140c from the plurality of fibers 140 are inclined obliquely with respect to a normal 150 to the first major surface 112. For example, the fiber 140c is inclined at an angle “Al” with respect to the normal 150. In some embodiments, the angle “Al” may be greater than zero degree and less than 90 degrees. In some other embodiments, the angle “Al” may be greater than 90 degrees and less than 180 degrees. In some embodiments, two or more fibers 140d from the plurality of fibers 140 are inclined obliquely with respect to each other. For example, the fibers 140d are inclined at an angle “A2” with respect to each other. In some embodiments, the angle “A2” may be greater than zero degree and less than 90 degrees. In some other embodiments, the angle “A2” may be greater than 90 degrees and less than 180 degrees. Each fiber 140 extends between two ends 142, 144. In some embodiments, the two ends 142, 144 of one or more fibers 140e from the plurality of fibers 140 are free. Specifically, the two ends 142, 144 of the fiber 140e is not attached to the adhesive layer 130.

In some embodiments, a length “LF” (shown in FIG. 4C) of each fiber 140 is equal to or greater than a length of the at least one side surface 124 of each microstructure 120. The length of the at least one side surface 124 may correspond to the height “H” of each microstructure 120. In some embodiments, the length “LF” of each fiber 140 is from about 1 time to about 3.5 times the length of the at least one side surface 124 of each microstructure 120. In some embodiments, the length “LF” of each fiber 140 is equal to or greater than the minimum width “W” of the bottom surface 172 of each groove 170. In some embodiments, a diameter “DF” (shown in FIG. 4C) of each fiber 140 is from about 8 micrometers to about 50 micrometers. The length “LF” and the diameter “DF” of each fiber 140 may vary based on application requirements. In some embodiments, the fibers 140 may have different lengths.

In some embodiments, one or more fibers 140f from the plurality of fibers 140 are adhered to the bottom surface 172 of one or more grooves 170 via the adhesive layer 130.

In some embodiments, the base film 110 includes a main surface 180. The main surface 180 (shown in FIG. 4A) of the base film 110 is defined by the top portion 122 and the at least one side surface 124 of each microstructure 120 and the bottom surface 172 of each groove 170. In some embodiments, the adhesive layer 130 is disposed on the main surface 180 of the base film 110. In some embodiments, the adhesive layer 130 covers at least 50% of a total area of the main surface 180. The plurality of fibers 140 may be attached to the main surface 180 of the base film 110 via the adhesive layer 130.

FIGS. 2A-2D illustrate schematic cross-sectional views of different types of microstructures that can be used to manufacture a flocked film according to the present disclosure.

FIG. 2A illustrates a plurality of microstructures 210. Each microstructure 210 includes a top portion 212 and a pair of side surfaces 214. Each microstructure 210 has a substantially square shape. In this embodiment, the top portion 212 is a substantially planar surface. Each side surface 214 is substantially perpendicular to the top portion 212. A bottom surface 216 extending between the side surfaces 214 of adjacent microstructures 210 is a substantially planar surface. In some embodiments, a height “HI” of each microstructure 210 may be from about 10 micrometers to about 1000 micrometers. A minimum width “Wl” of the bottom surface 216 may be from about 1 micrometer to about 500 micrometers. Further, a distance “Dl” between adjacent microstructures 210 may be from about 10 micrometers to about 1000 micrometers.

FIG. 2B illustrates a plurality of microstructures 220. Each microstructure 220 includes a top portion 222 and at least one side surface 224. In this embodiment, the top portion 222 is a curved surface. Further, each microstructure 220 includes a pair of side surfaces 224. Each side surface 224 is inclined to the top portion 222. In some other embodiments, the side surfaces 224 may be perpendicular to the top portion 222. A bottom surface 226 extending between the side surfaces 224 of adjacent microstructures 220 is a substantially planar surface. In some embodiments, a height “H2” of each microstructure 220 may be from about 10 micrometers to about 1000 micrometers. A minimum width “W2” of the bottom surface 226 may be from about 0 micrometer to about 500 micrometers. Further, a distance “D2” between adjacent microstructures 220 may be from about 10 micrometers to about 1000 micrometers.

FIG. 2C illustrates a plurality of microstructures 230. Each microstructure 230 has a substantially triangular shape. Each microstructure 230 includes a top portion 232 and a pair of side surfaces 234. The top portion 232 is a vertex. Each side surface 234 is inclined to the top portion 232. A bottom surface 236 extending between the side surfaces 234 of adjacent microstructures 230 is a substantially planar surface. In some embodiments, a height “H3” of each microstructure 230 may be from about 10 micrometers to about 1000 micrometers. A minimum width “W3” of the bottom surface 236 may be from about 0 micrometer to about 500 micrometers. Further, a distance “D3” between adjacent microstructures 230 may be from about 10 micrometers to about 1000 micrometers.

FIG. 2D illustrates a plurality of microstructures 240. Each microstructure 240 includes a top portion 242 and at least one side surface 244. In this embodiment, the top portion 242 is a curved surface. Further, each microstructure 240 includes a pair of side surfaces 244. The side surfaces 244 are inclined to the top portion 242. In this embodiment, a bottom surface 246 extending between the side surfaces 244 of adjacent microstructures 240 is also a curved surface. In some embodiments, a height “H4” of each microstructure 240 may be from about 10 micrometers to about 1000 micrometers. A minimum width “W4” of the bottom surface 246 may be from about 0 micrometer to about 500 micrometers. Further, a distance “D4” between adjacent microstructures 240 may be from about 10 micrometers to about 1000 micrometers.

FIGS. 3 A-3D illustrate schematic perspective views of different types of microstructures that can be used to manufacture a flocked film according to the present disclosure.

FIG. 3 A illustrates a plurality of microstructures 310 disposed on a base film 315. Each microstructure 310 includes a top portion 312 and at least one side surface 314. In this embodiment, the top portion 312 is a vertex. Further, each microstructure 310 includes a pair of side surfaces 314. Each side surface 314 is inclined to the top portion 312. A bottom surface 316 extending between the side surfaces 314 of adjacent microstructures 310 is a substantially planar surface. In some embodiments, the microstructures 310 are arranged in a rectangular grid. Microstructures 310 therefore intersect each other.

FIG. 3B illustrates a plurality of microstructures 320. In the illustrated embodiments, the microstructures 320 are separated by cuboidal recesses. Each microstructure 320 includes a top portion 322 and at least one side surface 324 of the adjacent cuboidal recess. In this embodiment, the top portion 322 is a substantially planar surface. The at least one side surface 324 is substantially perpendicular to the top portion 322. In some embodiments, the at least one side surface 324 may not be perpendicular to the top portion 322. A bottom surface (not shown) extending between the at least one side surfaces 324 of adjacent microstructures 320 may be a substantially flat surface.

FIG. 3C illustrates a plurality of microstructures 330 disposed on a base film 335. Each microstructure 330 includes a top portion 332 and at least one side surface 334. In this embodiment, the top portion 332 is a vertex. Further, each microstructure 330 includes a pair of side surfaces 334. Each side surface 334 is inclined to the top portion 332. A bottom surface 336 extending between the side surfaces 334 of adjacent microstructures 330 is a substantially planar surface.

FIG. 3D illustrates a plurality of microstructures 340 disposed on a base film 345. In this embodiment, each microstructure 340 is a cylindrical post extending from the base film 345. Each microstructure 340 includes a top portion 342 and one side surface 344. In this embodiment, the top portion 342 is a substantially planar surface. The side surface 344 is a curved surface. A bottom surface 346 extending between the side surfaces 344 of adjacent microstructures 340 is a substantially planar surface.

Referring to FIGS. 4A-4C and 5, the present disclosure further provides a method 500 of manufacturing the flocked film 100. The method 500 may also be used to manufacture flocked films from the microstructures 210, 220, 230, 240, 310, 320, 330, 340 described with reference to FIGS. 2A-2D and 3A-3D.

At step 502, the method 500 includes providing the base film 110 including the first major surface 112 and the second major surface 114 opposite to the first major surface 112. The plurality of microstructures 120 are disposed on the first major surface 112. The plurality of microstructures 120 may be provided by a typical micro-replication process. The micro replication process may include depositing a polymerizable composition or a thermoplastic composition onto a master negative microstructured molding surface in an amount barely sufficient to fill the cavities of the master. The cavities are then filled by moving a bead of the polymerizable composition between a preformed base or substrate layer (for example, the base film 110) and the master. The composition is then cured. Each microstructure 120 includes the top portion 122 and at least one side surface 124 extending between the top portion 122 and the first major surface 112. At step 504, the method 500 further includes providing the adhesive layer 130 on at least the first major surface 112 of the base film 110 and the at least one side surface 124 of each microstructure 120. In some embodiments, providing the adhesive layer 130 further includes providing the adhesive layer 130 on the top portion 122 of each microstructure 120. The formation of the adhesive layer 130 may include one or more of printing, coating, spraying, and masking steps.

At step 506, the method 500 further includes depositing the plurality of fibers 140 on the plurality of microstructures 120 and the first major surface 112 of the base film 110. In some embodiments, the method 500 includes depositing longer fibers prior to depositing shorter fibers. This may further improve an appearance of the flocked film 100. In some embodiments, depositing the plurality of fibers 140 on the plurality of microstructures 120 and the first major surface 112 of the base film 110 does not include applying an electric field.

At step 508, the method 500 further includes rubbing the plurality of fibers 140 onto the plurality of microstructures 120 and the first major surface 112 such that one or more fibers 140a from the plurality of fibers 140 are adhered to the at least one side surface 124 of one or more microstructures 120. Rubbing the fibers 140 may result in the attachment of at least some of the plurality of fibers 140 to the microstructures 120 and the first major surface 112 via the adhesive layer 130.

The disclosure is further described with reference to the following examples that explain preparation of a flocked film for triboelectric test. The examples will be explained in reference to FIGS. 6A-6D.

Table 1 provided below lists some exemplary materials that are used for the preparation of different flocked films for comparison. Tables 2 and 3 provided below include some exemplary dimensions of the micro-replicated film (Base Film 1).

Table 1: Materials List

Table 2: Distance between each microstructure

Each distance was measured by microscopy (KEYENCE CORPORATION, VHX- 600) or calculated by these values.

Comparative Example 1

Center part of a film (15 cm x 1.5 cm) was masked by a tape whose width was 1 cm (FIG. 6A) and it was sprayed with carbon spray (FIG. 6B). The film was not a micro- replicated film. After drying at 80 °C, masking tape at a center part of the film was removed and tapes were put on each edge parts (FIG. 6C). The film was sprayed by Spray type adhesive 55 (FIG. 6D) and 0.3 g of staple fibers (Nylon) were sprinkled onto the film. After rubbing its surface with aluminum foil and removing excess amount of staple fibers, the masking tapes were removed and a first film with a flocked surface was obtained (FIG. 6E). Comparative Example 2

Center part of a film (15 cm x 1.5 cm) was masked by a tape whose width was 1 cm (FIG. 6A) and it was sprayed with carbon spray (FIG. 6B). The film was not a micro- replicated film. After drying at 80 °C, masking tape at a center part of the film was removed and tapes were put on each edge parts (FIG. 6C). Film was sprayed by Spray type adhesive 55 (FIG. 6D) and 0.3 g of staple fibers (Polyester) were sprinkled onto the film. After rubbing its surface with aluminum foil and removing excess amount of stable fibers, the masking tapes were removed and a second film with a flocked surface was obtained (FIG. 6E). Example 1

Center part of the micro-replicated film, which is Base Film 1 (15 cm x 1.5 cm), was masked by a tape whose width was 1 cm (FIG. 6A) and it was sprayed with carbon spray (FIG. 6B). After drying at 80 °C, masking tape at a center part of the micro-replicated film was removed and tapes were put on each edge parts (FIG. 6C). The micro-replicated film was sprayed by Spray type adhesive 55 (FIG. 6D). 0.3 g of staple fibers (Nylon) were sprinkled onto the micro-replicated film. After rubbing its surface with aluminum foil and removing excess amount of stable fibers, the masking tapes were removed and a third film with a flocked surface was obtained (FIG. 6E).

Example 2

Center part of the micro-replicated film, which is Base Film 1 (15 cm x 1.5 cm), was masked by a tape whose width was 1 cm (FIG. 6A) and it was sprayed with carbon spray (FIG. 6B). After drying at 80 °C, masking tape at a center part of the micro-replicated film was removed and tapes were put on each edge parts (FIG. 6C). The micro-replicated film was sprayed by Spray type adhesive 55 (FIG. 6D). 0.3 g of staple fibers (Polyester) were sprinkled onto the micro-replicated film. After rubbing its surface with aluminum foil and removing excess amount of stable fibers, the masking tapes were removed and a fourth film with a flocked surface was obtained (FIG. 6E).

Visual and Tactile Sensation

Visual of each surface were observed by microscopy (KEYENCE CORPORATION, VnX-2000). Tactile sensation was investigated by touching with the hands.

Test of triboelectric generation based on flocked surface

Triboelectric charge was generated by continuously tapping polypropylene plate (10 cm x 10 cm x 1 mm) on flocked-surface films with staple fibers of Nylon. In the case of staple fibers based on PET, triboelectric charge between fingers and film surface was observed. Voltage generated by triboelectric effect was observed using an oscilloscope (TEKTRONIX, INC., DPO4054).

Table 3 includes some exemplary results of visual, tactile sensation and triboelectric performance test. Table 3: Results of visual, tactile sensation and triboelectric performance test

Visual A- Good

B - some parts of flocked surface seem to have low concentration

Tactile Sensation

A - High repulsive force B - Low repulsive force

Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

We claim:

1. A flocked film comprising: a base film comprising a first major surface, a second major surface opposite to the first major surface, and a plurality of microstructures disposed on the first major surface, wherein each microstructure comprises a top portion and at least one side surface extending between the top portion and the first major surface; an adhesive layer disposed on at least the first major surface of the base film and the at least one side surface of each microstructure; and a plurality of fibers adhered to the adhesive layer, wherein one or more fibers from the plurality of fibers are adhered to the at least one side surface of one or more microstructures.

2. The flocked film of claim 1, wherein the adhesive layer is further disposed on the top portion of each microstructure, and wherein one or more fibers from the plurality of fibers are adhered to the top portion of one or more microstructures.

3. The flocked film of claim 1, wherein one or more fibers from the plurality of fibers are inclined obliquely with respect to a normal to the first major surface.

4. The flocked film of claim 1, wherein two or more fibers from the plurality of fibers are inclined obliquely with respect to each other.

5. The flocked film of claim 1, wherein each fiber extends between two ends, and wherein the two ends of one or more fibers from the plurality of fibers are free.

6. The flocked film of claim 1, wherein a length of each fiber is equal to or greater than a length of the at least one side surface of each microstructure.

7. The flocked film of claim 6, wherein the length of each fiber is from about 1 time to about 3.5 times the length of the at least one side surface of each microstructure.

8. The flocked film of claim 1, wherein a diameter of each fiber is from about 8 micrometers to about 50 micrometers.

9. The flocked film of claim 1, wherein each fiber is conductive or non-conductive.

10. The flocked film of claim 1, wherein each fiber comprises carbon.

11. The flocked film of claim 1, further comprising a plurality of grooves alternating with the plurality of microstructures, wherein a bottom surface of each groove is defined by a portion of the first major surface extending between the at least one side surfaces of adjacent microstructures.

12. The flocked film of claim 11, wherein a main surface of the base film is defined by the top portion and the at least one side surface of each microstructure and the bottom surface of each groove, and wherein the adhesive layer is disposed on the main surface of the base film.

13. The flocked film of claim 12, wherein one or more fibers from the plurality of fibers are adhered to the top portion of one or more microstructures, and one or more fibers from the plurality of fibers are adhered to the bottom surface of one or more grooves.

14. The flocked film of claim 11, wherein a minimum width of the bottom surface of each groove is from about 0 micrometer to about 500 micrometers.

15. The flocked film of claim 11, wherein a minimum width of the bottom surface of each groove is from about 0 % to about 50% of a distance between adjacent microstructures.

16. The flocked film of claim 1, wherein a height of each microstructure is from about 10 micrometers to about 1000 micrometers, and wherein a maximum width of each microstructure is from about 10 micrometers to about 1000 micrometers.

17. The flocked film of claim 1, wherein a distance between adjacent microstructures is from about 10 micrometers to about 1000 micrometers.

18. The flocked film of claim 1, wherein the top portion of each microstructure is at least one of a surface, an edge and a vertex.

19. The flocked film of claim 1, wherein the film exhibits triboelectric voltage generation.

20. A method of manufacturing a flocked film, the method comprising: providing a base film comprising a first major surface, a second major surface opposite to the first major surface, and a plurality of microstructures disposed on the first major surface, wherein each microstructure comprises a top portion and at least one side surface extending between the top portion and the first major surface; providing an adhesive layer on at least the first major surface of the base film and the at least one side surface of each microstructure; depositing a plurality of fibers on the plurality of microstructures and the first major surface of the base film; and rubbing the plurality of fibers onto the plurality of microstructures and the first major surface such that one or more fibers from the plurality of fibers are adhered to the at least one side surface of one or more microstructures.

21. The method of claim 20, wherein providing the adhesive layer further comprises providing the adhesive layer on the top portion of each microstructure such that one or more fibers from the plurality of fibers are adhered to the top portion of one or more microstructures.

22. The method of claim 20, wherein depositing the plurality of fibers on the plurality of microstructures and the first major surface of the base film does not comprise applying an electric field.