Protective glass film
10377105 ยท 2019-08-13
Assignee
Inventors
- Young Taek Kim (Chungcheongnam-do, KR)
- Nam Tae Kim (Chungcheongnam-do, KR)
- Seok Bong Lyu (Chungcheongnam-do, KR)
- Ki Woong Choi (Chungcheongnam-do, KR)
Cpc classification
C09J2203/318
CHEMISTRY; METALLURGY
B32B5/16
PERFORMING OPERATIONS; TRANSPORTING
C08K2201/013
CHEMISTRY; METALLURGY
Y10T428/24405
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B2250/242
PERFORMING OPERATIONS; TRANSPORTING
C09J2301/206
CHEMISTRY; METALLURGY
B32B2264/0257
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24372
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
B32B5/16
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A glass protective film includes a base film formed by melting a weak adhesive polymer to be adhered to a glass plate by weak adhesion; a first surface of the base film prepared into a weak adhesive surface, which is a mirror surface; and a second surface thereof prepared into a non-adhesive surface which is a rough bead surface. Beads for preparing the rough bead surface are hexagonal, rectangular or triangular beads or ball beads prepared by cutting a film; and the ceiling reach rate of the beads of the rough bead surface is 30% or more.
Claims
1. A glass protective film, comprising: a base film with an adhesive surface as a first surface thereof and a rough bead surface as a second surface thereof, wherein the rough bead surface of the second surface of the base film comprises polymer film plate microbeads having a thickness, and all having a same regular shape with a size of 200 to 600 m, selected from any one of the following cut polymer film microbead shapes: hexagonal, rectangular, and triangular, and the polymer film plate microbeads being uniformly distributed with a density of between 0.1 g/m.sup.2 to 7 g/m.sup.2 on the rough bead surface.
2. The glass protective film of claim 1, wherein the cut microbeads are obtained by cutting at least one film selected from among a polyethylene film; high-density polyethylene, a polypropylene film, a polymethacrylate film, a polystyrene (PS) film, an acrylonitrile-butadiene-styrene (ABS) copolymer film, a HIPS (High Impact Polystyrene) film; a copolymer film containing a styrene monomer, a polyester film, a polyester elastomer film, a nylon elastomer film, a polyester-based polymer film; and a nylon-based polymer film.
3. The glass protective film of claim 1, wherein the base film comprises a low-density polyethylene.
4. The glass protective film of claim 1, wherein the polymer film plate microbeads have a predetermined hexagonal shape and a particle size range of 420 to 600 m.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying figures, in which like reference numerals refer to identical or functionally similar elements throughout the separate views, and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present disclosure, in which:
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DESCRIPTION OF THE REFERENCE NUMERALS IN THE DRAWINGS
(22) 11: base film, 12: weak adhesive surface, 13: rough bead surface, 1a: first layer, 10: glass protective film, 27: hexagonal bead, 37: rectangular bead, 47: triangular bead, 57: ball bead, 101: extruder, 102: die, 103: bead feeder, 104, 105: cooling roll, 11m: formed film, G: zone
DETAILED DESCRIPTION
(23) As disclosed in Korean Patent No. 10-0776197 excluding the use of an insert paper, U.S. Pat. No. 6,326,081 and CN Patent No. 101472981B, a glass protective film is configured such that the first surface of a base film has weak adhesion to a glass plate and the second surface thereof is a rough bead surface having no adhesion to a glass plate or a film.
(24) The glass protective film includes a coating adhesive film and a self-adhesive film depending on the extent of adhesion of the weak adhesive surface that is the first surface thereof. The coating adhesive film is configured such that an adhesive layer is applied on the surface coming into close contact with a glass plate, and an adhesive residue may be left behind on the surface of the glass plate after removal of the protective film from the glass plate. The adhesive residue which is left behind on the surface of the glass plate may have a negative influence on processes for manufacturing an LCD panel. The self-adhesive film is configured such that it is adhered by means of inherent adhesion of the base polymer therefor, instead of applying an additional adhesive layer on the surface coming into close contact with a glass plate. The polymer for the self-adhesive base film may include a low-density polyethylene-based polymer; a polyolefin-based polymer; an olefin-based monomer such as EVA, EAA or EMMA; a copolymer having a polar monomer; a polyolefin-based rubber; and other rubber materials.
(25) When a base film is manufactured by increasing the adhesive strength of the first surface coming into close contact with the glass plate, the amount of the adhesive residue which is left behind on the glass plate may increase with an enhancement in adhesion. To minimize the amount of the residue on the glass plate, a base film is manufactured using a polymer having weak adhesion, and the close contact surface is formed into a mirror surface, thus enhancing adhesion to the glass plate. This film may decrease peel strength while increasing a close contact force to the glass plate.
(26) In order to facilitate the post treatment including recovery after use of the glass protective film, in a suction duct in LCD processes, the second surface of the thin film having weak adhesion is made into a rough bead surface.
(27) To manufacture a film having a rough bead surface, a weak adhesive polymer is melted and then formed into a base film, after which microbeads are distributed and adhered to the second surface of the film while cooling and curing the film, so that the second surface of the film is formed into the rough bead surface. The base film for forming the rough bead surface may be a single layer film, a two-layer film or a three-layer film.
(28) As illustrated in
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(30) The microbeads are dropped onto the cooling rubber roll of the pair of cooling rolls from the bead feeder, and then transferred and attached to the second surface of the base film passing through the pair of cooling rolls. When the microbeads are dropped, a dropping distance is set between the rubber roll and the bead feeder. The dropping distance enables the microbeads to be uniformly distributed on the cooling rubber roll.
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(32) The particle size of the microbeads may fall in the range of 1000 m or less. When the microbeads are pulverized to a small size of 5 m or less, the microbeads may be lost in the air in the dropping distance zone. Also even when the microbeads are as small as about 20 m, a freefall time period may be retarded. If the particle size of the microbeads is excessively increased to 1000 m or more, the microbeads may protrude to be too high from the surface of the thin base film and may thus be removed due to pressure between glass plates. The particle size of the microbeads is preferably set to 50500 m in view of the freefall speed of the microbeads and the separation speed of each of the glass plates in LCD processes.
(33) The material for such microbeads may include an inorganic material including calcium carbonate or a polymer. However, the beads which are stably attached to the film to be cured may include polymer beads which may be strongly adhered to the polymer for the base film. In order to enhance adhesion efficiency between the microbeads and the protective film to be cured, the polymer for the microbeads has to have a melting temperature equal to or lower than that of the base film. However, in the adhering process for pressing and attaching microbeads to the protective film to be cured using the cooling rolls, adhesive affinity for adhering melted microbeads to the film is not essential. Even when the melting temperature of the polymer for the microbeads is higher than that of the base film, the microbeads may be stably attached to the surface of the film. Also, even when the polymer for the microbeads according to the present invention is a polymer having weak adhesion as in the base film, there is no problem in terms of non-adhesiveness depending on the rough bead surface.
(34) The low-density polymer for use in the microbeads includes a low-density polyethylene-based polymer; a polyolefin-based polymer; an olefin-based monomer such as EVA, EAA or EMMA; a copolymer having a polar monomer; polyolefin-based rubber; and other rubber materials.
(35) The high-density polymer for use in the microbeads may include polyethylene, polypropylene, polymethacrylate, polystyrene (PS), an acrylonitrile-butadiene-styrene (ABS) copolymer, HIPS (High Impact Polystyrene); a copolymer containing a styrene monomer, polyester, a polyester elastomer, a nylon elastomer, a polyester-based polymer; and a nylon-based polymer.
(36) The amount of the microbeads distributed to be adhesive on the second surface of the base film is 0.17 g/m.sup.2, and preferably about 3 g/m.sup.2.
(37) Such an LCD glass protective film has significantly contributed to the trend of increasing the size of an LCD substrate and to mass production thereof over the years. However, the demand for increasing the size of an LCD film requires more stringent quality of an LCD glass protective film, and price competitiveness in LCD markets needs to reduce the fabrication costs for glass protective films.
(38) Although the second surface of the glass protective film thus manufactured is prepared into the rough bead surface to thus surely exhibit non-adhesiveness, there is a need for inexpensive glass protective films having high quality because of the large size of the LCD panel and the price competitiveness in markets as mentioned above.
(39) Such a conventional film having a rough bead surface is illustrated in
(40) In the film having a rough bead surface, the ceiling reach rate of the microbeads is a factor showing the extent the microbeads attached to the film have reached the ceiling region 15.
(41) As seen in
(42) Method of Measuring Ceiling Reach Rate
(43) To measure the ceiling reach rate of a glass protective film, the following items should be investigated: film thickness (noted item), a measurement region (e.g. a rectangular region with a width of 5 cm and a length of 5 cm), the ceiling region range ab in the measurement region (high point a m, low point b m=a/2), the total number of measured beads BN, the number of beads reaching the ceiling region UBN, calculation of ceiling reach rate UN (UN=(UBN/BN)100).
(44) The ceiling reach rate of the film having a rough bead surface is represented as a percentage by counting the total number of beads in the sample area and counting the number of beads reaching the ceiling region (ab) as mentioned above.
(45) To evaluate the ceiling reach rate of the microbeads of the conventional film having a rough bead surface, a film sample having a rough bead surface comprising pulverized microbeads with a particle size of 50500 m is prepared. The ceiling reach rate of these microbeads is measured to be less than approximately 20%.
(46) In the fabrication of microbeads for the rough bead surface as the second surface of the conventional glass protective film, a low-density resin (LDPE) is prepared, and then pulverized by a disk mill. The pulverized low-density resin powder has an irregular particle shape or size and thus is sieved using a 40-mesh screen and a 50-mesh screen, thus sorting polymer particles with a particle size of 500600 m as normal microbeads.
(47) The preferable microbeads have a particle size of 500600 m with a spherical shape. The microbeads pulverized by a disk mill have various and irregular shapes as in the micrograph of
(48) The microbeads obtained by pulverizing a low-density resin (LDPE) by means of a disk mill are disadvantageous because the yield of normal microbeads is very low.
(49) The low-density resin is pulverized by a disk mill to prepare a polymer powder including normal microbeads, and the processing capability of such microbeads is evaluated.
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(51) In another embodiment, the yield of normal microbeads using a disk mill is only about 20 wt % or 16 wt %.
(52) The microbeads for forming the rough bead surface of a glass protective film may include beads having a maximum particle size of less than 1000 m, and the preferable particle size thereof is about 50500 m. When a powder comprising microbeads in a wide particle size of 50500 m is used for the glass protective film, the yield of microbeads by a disk mill may increase but a height variation of the beads attached to the base film may also increase, and thus the ceiling reach rate of the microbeads is remarkably lowered, undesirably remarkably deteriorating non-adhesive performance of the glass protective film. Further, even when the low-density polymer is pulverized using a disk mill and sorted to a particle size of 450550 m, it is difficult to completely separate fine particles. Hence, limitations are imposed on improving the ceiling reach rate of the beads of the rough bead surface of the glass protective film.
(53) With the goal of solving such problems, a glass protective film is proposed, which is manufactured by cutting the polymer film having a thickness of 550 m or less so as to have a regular shape with a predetermined size in the particle size range of 200600 m, thus obtaining regular microbeads, which are then attached in an amount of about 7 g/m.sup.2 to the base film.
(54) When the film having a predetermined thickness is cut by use of a cutter to thus make the cut regular microbeads, the size of the microbeads may fall in the preferable bead size range, thus increasing the yield of normal beads. Also, as the size variation of the beads may decrease, the ceiling reach rate of the beads of the rough bead surface of the glass protective film may increase, thereby improving the non-adhesive performance of the glass protective film and decreasing the risk of mixing of fine particles, ultimately reducing the generation of defects in LCD processes.
(55) The thickness of the film for the cut microbeads is preferably set to 150550 m.
(56) The low-density film for the cut microbeads may include a low-density polyethylene-based polymer film; a polyolefin-based polymer film; an olefin-based monomer film such as EVA, EAA or EMMA; a copolymer film having a polar monomer; a polyolefin-based rubber film; and other rubber films.
(57) The high-density polymer film for the cut microbeads may include a polyethylene film, a polypropylene film, a polymethacrylate film, a polystyrene (PS) film, an acrylonitrile-butadiene-styrene (ABS) copolymer film, a HIPS (High Impact Polystyrene) film; a copolymer film containing a styrene monomer, a polyester film, a polyester elastomer film, a nylon elastomer film, a polyester-based polymer film; and a nylon-based polymer film.
(58) Although the shape of the cut regular microbeads is not particularly limited, particularly useful are microbeads which facilitate the construction of a cutter for cutting a two-dimensional planar film without film debris. The microbeads which facilitate the construction of a cutter without the film debris may include hexagonal beads 27 as illustrated in
(59) The hexagonal beads 27 have a honeycombed planar configuration and may be cut without the film debris. The cut hexagonal plate shape is closer to a circular shape, and is thus the preferable shape of the microbeads. The honeycombed cutting is performed by cutting the film material while laterally moving it in a honeycombed pattern in a cutting cycle under the condition that the position of a rotary cutter is fixed.
(60) When not considering economic efficiency, the ball beads 57 illustrated in
(61) The ball beads 57 may be manufactured by melting polymer units thus obtaining polymer particles, to which surface tension is then applied to form spherical ball beads, or by grinding the cured polymer particles.
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(67) Specifically, a weak adhesive polymer is melted by an extruder 101, and then formed into a film 11m by a die 102. The formed film is cooled and cured while passing through a pair of cooling rolls 104, 105 and then wound on a roll 106. In the apparatus for forming a film, a bead feeder 103 is disposed over the cooling rubber roll 105 and a dropping distance G is given between the bead feeder 103 and the cooling rubber roll 105. The dropping distance G enables the cut microbeads to be appropriately distributed while passing through the air when being seated onto the cooling rubber roll 105 from the bead feeder 103. The pair of cooling rolls may include the cooling roll 104 for forming a mirror surface that is the weak adhesive surface 12 on the first surface of the base film 11, and the cooling rubber roll 105 for transporting the microbeads so as to be attached to the second surface of the base film 11. As the cooling rolls 104, 105 rotate while cooling the formed film, the cut microbeads (or ball beads) distributed and seated on the cooling rubber roll 105 are transferred without changing the distributed state thereof to the second surface of the film 11m to be cooled, and are then attached to the second surface of the base film 11 during the cooling of the film, thus obtaining a rough bead surface 13 having a regular size and shape of the microbeads. When the film formed of the weak adhesive polymer passes through the pair of cooling rolls in this way, the first surface of the base film 11 becomes a weak adhesive surface 12 as the mirror surface and the second surface thereof becomes a rough bead surface 13 onto which the microbeads are distributed and adhered.
(68) In the apparatus of
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(73) The cut microbeads prepared by cutting a film produce no fine powder in the course of preparation thereof, and the yield of normal microbeads is high, thus generating economic benefits.
(74) The glass protective film having a rough bead surface formed by the cut microbeads is greatly enhanced in non-adhesiveness thereof because the ceiling reach rate of the beads of the rough bead surface approximates 100%, resulting in an increased separation speed of the glass plates one by one.
VARIOUS EXAMPLES FOR EMBODIMENTS OF THE INVENTION
Example 1
Preparation Example of Glass Protective Film Using Hexagonal Beads
(75) Cut microbeads: Hexagonal beads
(76) Film for cutting beads: Low-density polyethylene film with a thickness of 250 m
(77) Particle size of beads: 450500 m
(78) Melting temperature of beads: 140 C.
(79) Weight of base film: 10 g/m.sup.2
(80) Use condition: Clean room
(81) Diameter of cooling rubber roll: 80 cm
(82) Line speed: 90 m/min
(83) Amount (volume) of attached beads: 5 g/m.sup.2
(84) Diameter of hexagonal bead-releasing holes arranged on bottom of hopper as bead feeder: 1.5 mm
(85) Interval between hexagonal bead-releasing holes: 2 cm
(86) Shaft for releasing hexagonal beads: Rotary hexagonal bar
(87) Dropping distance (G): 5 cm
Example 2
Preparation Example of Glass Protective Film Using Rectangular Beads
(88) Cut microbeads: Rectangular beads
(89) This example was performed in the same manner as in Example 1, with the exception that rectangular beads were used.
Example 3
Preparation Example of Glass Protective Film Using Triangular Beads
(90) Cut microbeads: Triangular beads
(91) This example was performed in the same manner as in Example 1, with the exception that triangular beads were used.
Example 4
(92) The properties of the LCD glass protective films of Examples 1 to 3 are as follows.
(93) i) Adhesion of film: Weak adhesion of a base film was the same as inherent adhesion of a polymer.
(94) ii) Non-adhesive properties of film:
(95) General characteristics: A rough bead surface was formed by adhering the cut regular beads to the second surface of a 10 g/m.sup.2 thin base film. The rough bead surface formed by the cut beads had a ceiling reach rate as high as 94100%, and thus, it was confirmed to exhibit excellent non-adhesiveness. Since an air layer was formed on the second surface of the base film by the rough bead surface having a high ceiling reach rate of the beads, separation properties of the stacked glass plates became very good when transporting such glass plates one by one.
(96) iii) General characteristics: The rough bead surface formed by attaching the hexagonal beads to the second surface of the 10 g/m.sup.2 thin base film did not show any impairment in the course of post recovery treatment after use of the film, in a suction hood. The hexagonal beads protruding from the base film acted as an elastic material between the stacked glass plates, thus increasing transport safety of the glass plates.
(97) Although the present specification may describe components and functions implemented in the embodiments with reference to particular standards and protocols, the disclosure is not limited to such standards and protocols. Each of the standards represent examples of the state of the art. Such standards are from time-to-time superseded by equivalents that may be faster or more efficient, but having essentially the same structures and/or functions.
(98) The illustrations of examples described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of devices, apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. Additionally, unless otherwise specifically expressed or clearly understood from the context of use, a term as used herein describes the singular or the plural of that term.
(99) The terms a or an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. Communicatively coupled refers to coupling of components such that these components are able to communicate with one another through, for example, wired, wireless or other communications media. The term communicatively coupled or communicatively coupling includes, but is not limited to, communicating electronic control signals by which one element may direct or control another. The term configured to describes hardware, software or a combination of hardware and software that is adapted to, set up, arranged, commanded, altered, modified, built, composed, constructed, designed, or that has any combination of these characteristics to carry out a given function. The term adapted to describes hardware, software or a combination of hardware and software that is capable of, able to accommodate, to make, or that is suitable to carry out a given function.
(100) Although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. The examples herein are intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, are contemplated herein.
(101) The Abstract is provided with the understanding that it is not intended be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.
(102) The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description herein has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the examples in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the examples presented or claimed. The disclosed embodiments were chosen and described in order to explain the principles of the embodiments and the practical application, and to enable others of ordinary skill in the art to understand the various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the appended claims below cover any and all such applications, modifications, and variations within the scope of the embodiments.