Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/58—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres
  • B29C70/64—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres the filler influencing the surface characteristics of the material, e.g. by concentrating near the surface or by incorporating in the surface by force
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D7/00—Producing flat articles, e.g. films or sheets
  • B29D7/01—Films or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G49/00—Conveying systems characterised by their application for specified purposes not otherwise provided for
  • B65G49/05—Conveying systems characterised by their application for specified purposes not otherwise provided for for fragile or damageable materials or articles
  • B65G49/06—Conveying systems characterised by their application for specified purposes not otherwise provided for for fragile or damageable materials or articles for fragile sheets, e.g. glass
  • B65G49/068—Stacking or destacking devices; Means for preventing damage to stacked sheets, e.g. spaces
  • B65G49/069—Means for avoiding damage to stacked plate glass, e.g. by interposing paper or powder spacers in the stack
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/06—Polyethene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G2249/00—Aspects relating to conveying systems for the manufacture of fragile sheets
  • B65G2249/02—Controlled or contamination-free environments or clean space conditions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2300/00—Characterised by the use of unspecified polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/04—Homopolymers or copolymers of ethene
  • C08J2323/06—Polyethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/16—Applications used for films

Definitions

• the present invention relates to an LCD glass protective film and a method for manufacturing the same. More particularly, the present invention relates to an LCD glass protective film, having a slightly adhesive inner surface and a non-adhesive outer surface, which makes it unnecessary to use a paper insert when stacking LCD glass plates, and a method for manufacturing the same.
• Background Art
• [2] LCD glass is kept clean in a clean room before thin film transistors are fabricated thereon.
• a protective film is used to protect the LCD glass and keep the LCD glass clean during transportation from an LCD glass production location to a transistor fabrication location.
• a paper insert is used as such a glass protection means.
• a protective film is attached on either surface of a glass plate, and a paper insert is placed between the protective films when the glass plates are stacked.
• a paper insert between pieces of glass is likely to make micro scratches on glass surface and leave contaminants thereon, which results in degradation of the quality of the LCD glass. Therefore, pieces of glass having paper between them may be required to be intensively cleansed with a cleanser before a thin film fabrication process. However, residue of the cleanser is apt to remain on the surface of the glass.
• [3] LCD glass plates which have protective films attached to the surfaces thereof with an insert placed between the films are more safely protected from micro scratches than those between which a paper insert alone is inserted.
• a lower glass plate may be attached to an upper glass plate, fall, and break. If both a protective film and a paper insert are used, additional work and expense are incurred. In addition, the paper insert produces dust, thereby lowering the cleanness of the glass.
• LDC glass plates as thin as 1 mm and having large areas entail a high breakage rate even if two people carefully handle them. Disclosure of Invention
• the present invention provides a glass protective film, comprising a slightly adhesive surface and a rough microbead surface studded with a large number of microbeads, the microbeads being embedded in one side of the glass protective film to form the rough microbead surface while the glass protective film is molded and cured from a molten, slightly adhesive base material.
• the microbeads are less than 1000 ⁇ m in size and are distributed at a density of 3 g/m2.
• the rough microbead surface may be formed by freely dropping and distributing the microbeads from a release apparatus over a cooling roll.
• the microbeads are made of a polymer selected from a group consisting of low density polyethylene, high density polyethylene, polypropylene, polymethacrylate, polystyrene (PS), acrylonitrile butadiene styrene (ABS) copolymer, HIPS (High Impact Polystyrene), a copolymer based on styrene monomers, polyester, polyester elastomer, nylon elastomer, polyester polymer, nylon polymer and combinations thereof.
• the base material is low density polyethylene.
• a method for manufacturing a glass protective film comprising: melting a polymer base material in an extruder and forming the molten base material into a pre-cured film in a die; freely dropping microbeads 1000 ⁇ m or less in size onto one of a pair of two cooling rolls engaged with each other to distribute them over the one cooling roll; and passing the pre-cured film between the two cooling rolls under pressure to stud the pre-cured film with the microbeads on one surface of the film.
• FIG. 1 shows the structure of a conventional glass protective film.
• the conventional glass protective film 1 is comprised of a base film having a slightly adhesive surface and a non-adhesive surface 3.
• another conventional glass protective film is shown in cross sectional view.
• this conventional glass protective film 1 is a composite film, composed of a first layer Ia, a second layer Ib and a third layer Ic, having a slightly adhesive surface 2 and a non-adhesive surface 3.
• Glass protective films are classified as adhesive layer-coated films and self- adhesive films according to method of imparting adhesiveness to the slightly adhesive surface 2.
• An adhesive layer-coated film has an adhesive coating layer which is to be brought into contact with a glass surface. When peeled off, the adhesive layer-coated film tends to leave adhesive residue. Such residue on the glass surface may be a crucial hindrance to the manufacture of an LCD.
• the self-adhesive film can be adhered to the glass by the adhesiveness of the base material itself, without the attachment of an additional adhesive layer thereon.
• the base material for the contacting surface of the self-adhesive film is low density polyethylene.
• an olefin polymer a copolymer of an olefin monomer, such as EVA, EAA or EMMA, and a polar monomer; a polyolefin rubber; or other rubber may be used.
• a base material is designed to have high adhesiveness to the glass surface, the amount of adhesive residue on the glass surface is also increased.
• the base material is provided with a specular surface having weak adhesiveness. This film has a large contact area, but low peel strength.
• the non-adhesive surface 3 is responsible for making the upper surface of the protective film rough. When in contact with a glass plate, a large number of air cells or air layers are trapped between the rough surface and the glass surface, thereby preventing the film from adhering to the glass and lowering the resistance to separation of one glass plate from another. In conventional non-adhesive surfaces, prevention of adhesion to glass plates is achieved by adding inorganic materials to the binder.
• the glass protective film 10 comprises a base layer 11 consisting of a slightly adhesive surface 12 and a rough microbead surface 13 studded with a large number of microbeads 17.
• the base layer is made of a slightly adhesive material. While the slightly adhesive material is melted and cured to form a film, microbeads 17 are embedded in the adhesive material on one side thereof to form the rough microbead surface 13.
• the glass protective film 10 is a composite film 11, composed of a first layer 1 Ia, a second layer 1 Ib, and a third layer l ie, having a slightly adhesive surface 12 and a rough microbead surface 13 studded with a large number of microbeads 17.
• FIG. 7 a process for manufacturing a glass protective film in accordance with an embodiment of the present invention is illustrated.
• a base material is melted in an extruder 101 and extruded in the form of a pre-cured film m through a die 102.
• the pre-cured film m is run between a pair of cooling rolls 104 and 105 to form the glass protective film. While it is run between the cooling rolls 104 and 105, the pre-cured film m is studded with microbeads 17 on one surface.
• the microbeads 17, having a size of 1,000 ⁇ m or less are freely dropped from a release apparatus 103 onto the cooling roll 105 and transferred onto one surface of the film when the film passes between and is pressed by the cooling rolls 104 and 105. After falling the freefall distance G to the cooling roll 105, the microbeads 17 are distributed over the cooling roll 105, as shown in FIG. 3.
• the present invention provides a method for manufacturing a glass protective film, comprising: melting a base material and extruding the melt into a pre-cured film; freely dropping microbeads 1000 ⁇ m or less in size onto one of a pair of two cooling rolls engaged with each other to distribute them over the one cooling roll; and passing the pre-cured film between the two cooling rolls under pressure to stud one surface of the pre-cured film with the microbeads.
• microbeads 17a attached to the film m are shown in a magnified view.
• the microbeads distributed over the cooling roll 105 are transferred onto one surface of the film m and are embedded in the film 11 by pressure.
• the microbeads 17 are stably fixed within the film 11 via an adhesive layer 18, so that they are prevented from falling off the film. Therefore, the freely distributed microbeads 17 form the rough microbead surface 13, providing a stable non-adhesive surface.
• the microbeads 17 are 1,000 ⁇ m or less in particle size. If the particle size of the microbeads is less than 5 ⁇ m, they are blown away, and do not land on the cooling roll. If the microbeads are smaller than 20 ⁇ m in size, the freefall time is too long. On the other hand, microbeads exceeding 1000 ⁇ m in size, even if they are successfully embedded in the film, protrude too much to stably support the glass plates when they are stacked. Further, when the glass plates are stacked, big microbeads are apt to fall off because they must individually support large loads. In consideration of the freefall speed and the glass handling, the microbeads preferably range from 50 to 500 ⁇ m in size.
• the microbeads may be made of inorganic materials, including calcium carbonate, or polymers. Polymers are preferred because they are stably attached to the polymer of the film when it is cured from a molten state. To be better attached to the polymer of the film, the microbeads preferably have a melting point that is the same as or lower than that of the polymer.
• the process of embedding microbeads in the pre- cured film by pressing with the cooling rolls in accordance with the present invention makes it possible to stably attach polymeric microbeads to the film, irrespective of whether their heat-adhesive compatibility is poor and whether their melting point is higher than that of the base material. Even if they are made of materials having slight adhesiveness, like the base material, the microbeads of the present invention present no obstacle to the provision of a non-adhesive surface.
• the microbeads 17 are made of low density polymers or high density polymers.
• low density polymers examples include low density polyethylene; polyolefins; copolymers of olefin monomers, such as EVA, EAA and EMMA, and monomers having polar group; poly olefin rubber; and other rubbers.
• the high density polymers they may be polyethylene, polypropylene, poly- methacrylate, polystyrene (PS), acrylonitrile butadiene styrene (ABS) copolymers, HIPS (High Impact Polystyrene), copolymers based on styrene monomers, polyester, polyester elastomers, nylon elastomers, polyester polymers, or nylon polymers.
• PS polystyrene
• ABS acrylonitrile butadiene styrene
• HIPS High Impact Polystyrene
• copolymers based on styrene monomers polyester, polyester elastomers, nylon elastomers, polyester polymers, or nylon polymers.
• micro beads 17 attached onto the rough surface of the film is distributed in a density of 0.1-7 g/m2, and preferably in a density of around 3 g/m2.
• microbeads 17a are randomly distributed over the film by continuously releasing micro beads 17 from the release apparatus 103 in a freefall manner.
• the distribution of the microbeads 17a may alternatively be accomplished by electrostatic coating or roll coating.
• roll coating a powder-providing roll or doctor blading are usually used. In consideration of the mechanical circumstances and the cost of manufacturing the film, a freefall method is preferred.
• the microbead release apparatus 103 comprises a microbead hopper, bead-releasing holes arranged under the hopper at regular intervals along the entire width of the die, bead releasing axes provided in contact with the inner circumferences of the releasing holes, and a support for adjusting the gap between the releasing holes and the cooling roll.
• the LCD glass protective film of the present invention is made of a base material which is itself slightly adhesive to glass plates and is provided with an innovative non-adhesive rough surface.
• microbeads are embedded in one side to form the rough microbead surface while the glass protective film is molded and cured from a molten, slightly adhesive base material.
• the LCD glass protective film has a non-adhesive surface which allows easy film removal after use. In addition, the non-adhesive surface allows glass plates to be transported safely.
• the glass protective film can be manufactured by melting a polymer base material in an extruder and forming the molten base material into a pre- cured film in a die, freely dropping microbeads 1000 ⁇ m or less in size onto one of a pair of two cooling rolls engaged with each other to distribute them over the one cooling roll, and passing the pre-cured film between the two cooling rolls under pressure to stud one surface of the pre-cured film with the microbeads.
• FIG. 1 is a cross sectional view showing the structure of a conventional glass protective film.
• FIG. 2 is a cross sectional view showing the structure of another conventional glass protective film
• FIG. 3 is a front view showing micro beads freely distributed over the surface of a cooling rubber roll
• FIG. 4 is a cross sectional view showing the structure of a glass protective film in accordance with the present invention, which features microbeads embedded in one surface of the film;
• FIG. 5 is a magnified view showing the deformed state of the film around the embedded micro beads
• FIG. 6 is a cross sectional view showing the structure of a multilayer film in accordance with the present invention, which features microbeads embedded in one surface of the film;
• FIG. 7 is a schematic view showing an apparatus for manufacturing a glass protective film in accordance with one embodiment of the present invention.
• FIG. 8 is a schematic view showing an apparatus for manufacturing a glass protective film in accordance with another embodiment of the present invention. Best Mode for Carrying Out the Invention
• Base material low density polyethylene
• Micro bead polymer low density polyethylene
• Microbead releasing axis rotary hexagon bar
• Non-adhesive properties General characteristics: Microbeads protruding from the film, which was as light as 10 g/m2, provided a non-adhesive, rough surface. When glass plates were stacked, air was trapped between the microbeads protruding from the film, guaranteeing the excellent separation of glass plates from each other when they were transferred one by one.
• the LCD glass protective film in accordance with the present invention is being manufactured by the applicant, Hanjin P&C, and purchased by Samsung Corning Co. Ltd., a manufacturer of LCD glass panels.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Composite Materials (AREA)
• Materials Engineering (AREA)
• Laminated Bodies (AREA)
• Adhesive Tapes (AREA)
• Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
• Surface Treatment Of Glass (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

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• 2006
  • 2006-06-20 KR KR1020060055435A patent/KR100776197B1/ko active IP Right Grant
  • 2006-09-22 JP JP2009516388A patent/JP5053371B2/ja active Active
  • 2006-09-22 CN CN2006800550452A patent/CN101472981B/zh active Active
  • 2006-09-22 WO PCT/KR2006/003765 patent/WO2007148849A1/en active Application Filing

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