JP2006099018A - Polarizing plate stripping system of liquid crystal display panel and recycling method of liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system capable of efficiently stripping a polarizing plate from a liquid crystal display panel, and to provide a recycling method capable of continuously separating display element constituent material from the liquid crystal display panel from which the polarizing plate is stripped and performing recycling of a glass substrate. <P>SOLUTION: In the polarizing plate stripping system of a liquid crystal display panel 10, the polarizing plate stuck with tacky adhesive agent is stripped from the glass substrate, wherein a heat loading part chart 7(A) for reducing adhesion power of the tacky adhesive agent and a stripping part chart 7(B) for adhering a tape 42 to one edge side of the polarizing plate after adhesion power reduction with the tacky adhesive agent are provided and the polarizing plate is stripped by winding the adhered tape according to the stripping part chart 7(C). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display panel having a pair of glass substrates in which a liquid crystal material is sealed and held by a seal portion, and a polarizing plate pasted with an adhesive on the outer surface of the pair of glass substrates. The present invention relates to a polarizing plate peeling system for a liquid crystal display panel that peels a plate from a glass substrate, and a method for reusing the liquid crystal display panel from which the polarizing plate is peeled by the system.

  In recent years, liquid crystal display panels have been used as flat display devices for displaying images and the like. FIG. 9 is a cross-sectional view for explaining the schematic structure of such a liquid crystal display panel. A pair of glass substrates 01 and 02 are held at regular intervals by spacers 03, and a liquid crystal material 05 is sealed inside by a seal member 04. ing. The liquid crystal side of the glass substrates 01 and 02 is provided with alignment films 06 and 07 and transparent electrodes 08 and 09 for controlling the alignment of liquid crystal molecules in a predetermined direction, respectively. Polarizing plates 010 and 011 arranged so that their polarization axes are orthogonal to each other are attached via an adhesive.

  These polarizing plates 010 and 011 are attached to the glass substrates 01 and 02 when used as a liquid crystal display panel, but dust and scratches were found on the polarizing plates 010 and 011 during the manufacturing process of the liquid crystal display panel. In such a case, it is necessary to peel off the once-applied polarizing plates 010 and 011 from the glass substrates 01 and 02 and re-attach the normal polarizing plates 010 and 011. On the other hand, when the liquid crystal display panel that has been used for a long time is disposed of, the glass substrate 01 of the polarizing plates 010 and 011 can be reused as polished glass by separating the glass substrate from the others. The peeling from 02 is indispensable.

  As a conventional peeling method of a polarizing plate developed under such circumstances, there is known a method in which an edge of a polarizing plate is wound up by a winding roller (see Patent Document 1). FIG. 10 is a plan view showing such a conventional polarizing plate peeling method, and the liquid crystal display panel 1 is moved in the A direction on the transfer device. The end 3 a of the polarizing plate 3 is peeled off by about 20 to 30 mm with a tool, and the peeled portion is wound around the take-up roller 7 via the double-sided adhesive tape 5. After passing through such a preparatory stage, if the take-up roller 7 is rotationally driven by a motor or the like while the lift of the liquid crystal display panel 1 is suppressed by the pressing roller 4, the polarizing plate 3 is moved as the liquid crystal display panel 1 advances in the A direction. Is gradually peeled off, and eventually the polarizing plate 3 is completely peeled off from the glass substrate 9.

JP-A-9-197394 (paragraphs 0020-0023, see FIG. 2)

  However, in the peeling method described in Patent Document 1, when the end 3a of the polarizing plate 3 is wound around the take-up roller 7, a part of the polarizing plate 3 must first be peeled off from the glass substrate 9 with a tool such as a cutter. It takes a lot of skill and time to roll up the thin polarizing plate 3, and is particularly unsuitable for removing the polarizing plate from a large amount of waste liquid crystal display panel and reusing the glass substrate. .

  The present invention has been made in view of such circumstances, and a system for efficiently peeling a polarizing plate from a liquid crystal display panel, and a display element constituent material continuously from the liquid crystal display panel from which the polarizing plate has been peeled off. An object of the present invention is to provide a reuse method for separating and reusing a glass substrate.

In order to solve the above problem, a polarizing plate peeling system for a liquid crystal display panel according to claim 1 of the present invention includes a pair of glass substrates enclosing and holding a liquid crystal material by a seal portion, and the pair of glasses. A liquid crystal display panel having a polarizing plate attached to an outer surface of a substrate with a pressure-sensitive adhesive, wherein the pressure-sensitive adhesive is a polarizing plate peeling system for a liquid crystal display panel that peels the polarizing plate attached with the pressure-sensitive adhesive from a glass substrate. A step of reducing the adhesive strength of the adhesive, a step of adhering the tape with an adhesive to one end side of the polarizing plate after the reduction of the adhesive strength, and a step of winding up the adhered tape.
According to this feature, since the adhesive strength of the adhesive is reduced, there is no need to peel off part of the polarizing plate from the glass substrate with a tool such as a cutter as in the prior art, and the polarizing plate can be efficiently peeled off.

The polarizing plate peeling system for a liquid crystal display panel according to claim 2 of the present invention is the polarizing plate peeling system for a liquid crystal display panel according to claim 1, wherein the step of reducing the adhesive strength of the pressure sensitive adhesive is a pressure sensitive adhesive. It is characterized by being a means for applying a heat load.
According to this characteristic, it can respond to the various polarizing plates from which an adhesive differs by applying the heat load according to the property of an adhesive.

A polarizing plate peeling system for a liquid crystal display panel according to claim 3 of the present invention is the polarizing plate peeling system for a liquid crystal display panel according to claim 1 or 2, wherein the adhesive has a reduced adhesive force. It is characterized by greater than the adhesive strength of.
According to this feature, since the adhesive strength of the adhesive is greater than the adhesive strength of the adhesive, the polarizing plate can be reliably peeled off without separating the tape from the polarizing plate in the middle.

A polarizing plate peeling system for a liquid crystal display panel according to a fourth aspect of the present invention is the polarizing plate peeling system for a liquid crystal display panel according to any one of the first to third aspects, wherein the step of winding the tape is a pair. It is characterized by having means for rotating the roller by sandwiching the tape between the rollers.
According to this feature, the polarizing plate can be peeled off with a uniform force by winding the tape with the winding roller.

The method for reusing a liquid crystal display panel according to claim 5 of the present invention is to recycle the liquid crystal display panel from which the polarizing plate has been peeled off by the polarizing plate peeling system for the liquid crystal display panel according to any one of claims 1 to 4. A method for reusing a liquid crystal display panel to be used, in which a seal portion is cut with a cutter and separated into two glass substrates, and inner grinding of both glass substrates is performed with a diamond wheel. It is characterized by separating.
According to this feature, it is possible to perform efficient dismantling work at a low cost by separating the display element constituent material adhering to the glass substrate with a cutter using a method of grinding with a diamond wheel. .

A method for reusing a liquid crystal display panel according to a sixth aspect of the present invention is the method for reusing a liquid crystal display panel according to the fifth aspect, wherein the liquid crystal display panel is transported to a transport device while polarizing plate, glass The substrate and the display element constituent material are separated.
According to this feature, a series of operations can be completed while transporting the liquid crystal display panel, so that it can be continuously performed even for a large amount of dismantling operations.

  Examples of the present invention will be described below.

  FIG. 1 is a model diagram of a liquid crystal display panel used in the present invention, FIG. 2 is a partially enlarged perspective view of a polarizing plate, FIG. 3 is a diagram showing a polarizing plate peeling system, and FIG. A process figure, (b) shows a tape adhesion process figure, and (c) shows a winding process figure of a tape.

  As shown in FIG. 1, reference numeral 10 denotes a liquid crystal display panel, which is held at a predetermined interval by a spacer 12, a pair of glass substrates 14 and 16, a liquid crystal material 20 enclosed between glass substrates 14 and 16 by a seal member 18, glass An alignment film and a transparent electrode (hereinafter referred to as a display element constituent) 22 disposed on the liquid crystal side of the substrates 14 and 16, and polarizing plates 30 and 30 adhered to the outer surface side of the glass substrates 14 and 16.

  As shown in FIG. 2, the polarizing film 30 is formed by polymerizing a release film 33, an adhesive layer 34, a substrate film 35, a polarizing film 36, a substrate film 37, and a protective film 38. The adhesive layer 34 is attached to the glass substrates 14 and 16.

  As the polarizing film 36, a hydrophilic polymer film such as a PVA (polyvinyl alcohol) film is used which is stretched by adsorbing iodine or a dichroic dye, and the thickness thereof is about 5 to 80 μm. It is not limited to this. The protective film 38 is preferably a plastic excellent in transparency, mechanical strength, and thermal stability. As the pressure-sensitive adhesive layer 34, an acrylic pressure-sensitive adhesive is mainly used, and the adjustment is performed, for example, by blending an epoxy-based cross-linking agent with a liquid containing an acrylic copolymer.

  A system for peeling the polarizing plate 30 attached by the adhesive layer 34 in this way will be described. The pressure-sensitive adhesive 34 is of a type that is liquefied and decreases its adhesive strength when heated, or of a type that adheres mainly by van der Waals force, which decreases its adhesive strength when cooled rather than heated. Alternatively, there are types that can be peeled off by interfacial stress by performing rapid heating and rapid cooling (thermal shock) using the difference in linear expansion coefficient with the adherend, and a thermal load is applied according to each type.

  FIG. 3A shows a process of applying a thermal load to the adhesive 34 from the outside of the liquid crystal display panel 10 via the protective film 38 by the Peltier cooler 40 in order to reduce the adhesive strength of the adhesive 34. Thus, one surface of the liquid crystal display panel 10 is placed on the cooling plate surface 40 a of the Peltier cooler 40.

  Then, after the adhesives 34 on both sides are cooled, as shown in FIG. 3B, the tape 42 is bonded to one end side of the protective film 38 of the liquid crystal display panel 10 with an adhesive as shown in FIG. This adhesive has good adhesive properties at low temperatures, and the adhesive strength is naturally higher than that of the reduced adhesive.

  The tape 42 thus adhered to the protective film 38 is taken up by a motor M that is sandwiched between a pair of take-up rollers 44 and 46 and connected to the other roller 44, as shown in FIG. By winding the tape with the take-up rollers 44 and 46 in this manner, the polarizing plate 30 can be peeled off with a uniform force, and the adhered polarizing plate 30 is reliably peeled off from the glass substrate 14. After peeling off the polarizing plate 30 on one side, the other polarizing plate 30 is similarly peeled off from the glass substrate 16. And the remainder of the adhesive left on the glass substrate is completely removed with an aqueous cleaning agent.

  In the above description, the adhesive has been described as a type in which the adhesive strength decreases with respect to cooling, but the type in which the adhesive strength decreases with respect to heating and the type in which the adhesive strength decreases with respect to rapid heating and rapid cooling are It is sufficient to apply a heat load at an appropriate temperature according to each type.

  A second embodiment in which the liquid crystal display panel with the polarizing plate isolated in this way is further disassembled and the glass substrate is reused as a raw glass or as a glass raw material will be described with reference to FIGS.

  FIG. 4 is a perspective view showing a process of cutting a sealing member with a cutter in a liquid crystal display panel from which a polarizing plate is isolated, and FIG. 4A shows a state in which two opposing sides of a rectangular panel are cut off, FIG. 4B shows a state in which the other two opposite sides of the rectangular panel are cut off, and FIG. 4C is a schematic front view showing the cutting position in FIG. FIG. 5 is a process diagram showing a state of cleaning the inscribed surface side of the separated glass substrate, and FIG. 6 is a perspective view showing a process of grinding the inner surface of the liquid crystal side of the glass substrate from which the sealing member is removed with a diamond wheel. .

  As shown in FIG. 4A, the liquid crystal display panel 50 from which the polarizing plate has been peeled has a rectangular panel shape with the double cutters C and C along the cutting lines C1 and C2 so that the seal portion 18 is cut off. One opposing two sides are excised. Subsequently, as shown in FIG. 4B, the liquid crystal display panel 51 with two sides cut off is rotated by 90 degrees, and the other two opposite sides are similarly cut along the cutting lines C3 and C4. , C excise. FIG. 4C is a schematic front view showing the cutting position of FIG. 4B, and the portion cut by the double cutters C and C is slightly inside the seal portion 18 as shown by the one-dot chain line in the drawing. .

  When the four-side seal member 18 is cut, the two glass substrates 14 and 16 are separated. As shown in FIG. 5, the spacer and the liquid crystal material that existed between the two contact surfaces of the glass substrates 14 and 16 are composed of a surfactant having a good solubility and a rinsing property, and a cleaning agent mainly composed of a solvent. It sprays with the spreader 53 from the upper part, is washed away, and is removed. Next, the display element constituting material 22 including the electrodes left on the glass substrates 14 and 16 is placed on the table of the grinding machine, facing upward.

  As shown in FIG. 6, the glass substrate 14 placed on the table of the grinding machine includes electrodes attached to the contact surface using a diamond wheel 54 having a plurality of slits for cooling water around it. All of the display element constituent material 22 is ground to form a polished surface 14 a free from impurities on the glass substrate 14. Similarly, all of the display element constituting material 22 is ground on the other glass substrate 16.

  As a grinding tool, an electrodeposition wheel fixed with diamond or CBN (steric boron nitride) may be used. However, the diamond wheel can peel the display element constituent material from the substrate more quickly and reliably. The glass substrate thus obtained can be reused as raw glass or as a glass raw material. Moreover, Ag, Sn, and In which become noble metals can also be collect | recovered among compositions, such as an electrode contained in the sludge formed by grinding.

  The invention of Example 3 in which the waste liquid crystal display panel is transported to the transport device and the polarizing plate is peeled off, the glass substrate is separated, and the display element constituent material is ground will be described with reference to the schematic flow diagram of FIGS. . FIG. 7 is a diagram illustrating a process for peeling a polarizing plate, and FIG. 8 is a diagram illustrating a process for separating a glass substrate and grinding a display element constituent material.

  As shown in FIG. 7, the liquid crystal display panel 10 to be reused is taken out from the recovery pallet and cooled for a required time in the Peltier cooling chamber P of the heat load portion (A), and then the next peeling portion ( B). In this peeling portion (A), the adhesive tape 42 is bonded to the surface of the polarizing plate, and is taken up by the pair of winding rollers 44 and 46 to peel off the polarizing plate. The polarizing plate is peeled off while the liquid crystal display panel 10 is being transported by the transport conveyor 62. In order to prevent the liquid crystal display panel 10 from being lifted off, the transport conveyor 62 is provided with a holding rod 63.

  After the polarizing plate is peeled off from the glass substrate, the process proceeds to the next reversing section (c), where the liquid crystal display panel 10 is reversed by the vacuum suction device 64 and placed on the mounting table 66. Then, the liquid crystal display panel 10 is transferred by the transport conveyor 68 again at the second peeling portion (D), and the polarizing plate on the back surface side is peeled off.

  As shown in FIG. 8, the liquid crystal display panel 50 from which the polarizing plates on both sides are peeled off is a pair of opposing sides by the double cutter C driven by the motor M while being transferred by the transport conveyor 70 in the cutting part (v). Is disconnected. At this time, the seal member is cut with a cut width that is completely removed.

  Next, the liquid crystal display panel 51 with the pair of opposed sides cut is moved to the reversing part (f) and rotated by 90 ° by the turntable 72 of the reversing part (f). The liquid crystal display panel 51 rotated by 90 ° is moved to the second cutting section (G) for cutting again. Similarly to the first cutting section (v), the second cutting section (ki) is composed of a transport conveyor 74 for transporting the liquid crystal display panel 51 and two cutters C and is driven by a motor M. By passing the cutter C, the other facing side where the seal portion of the liquid crystal display panel 51 still remains is cut.

  After the seal portion is cut off, the liquid crystal display panel 51 is separated into two glass substrates 14 and 16 by the separation portion (ku) and placed on the placement table 76. In this separation part (g), the spacer and the liquid crystal material that existed between the two contact surfaces of the glass substrates 14 and 16 are washed away with the cleaning agent from the spreader 53.

  After the liquid crystal material or the like is washed away, the glass substrates 14 and 16 are carried one by one to the grinding portion (piece) with the display element constituent material facing upward. A plurality of (seven in this embodiment) rotating diamond wheels 54 arranged in two rows are laterally provided in the grinding portion (single), and the glass substrate passes through the diamond wheel 54, whereby a display element configuration is obtained. The material is peeled off. At the time of peeling, it is preferable to always spray cooling water from the peripheral surface of the diamond wheel 54. The substrate after the peeling operation is unloaded from the transfer conveyor 78, which is a transfer device, and temporarily stored in a storage pallet (not shown).

  According to the reuse method as described above, the display element constituting material including electrodes attached to both contact surfaces of the glass substrate can be cut simultaneously by using two cutters for cutting. By installing a plurality of diamond wheels, the diamond wheels can be reliably peeled off, and an expensive special tool is not used, so that an efficient and efficient disassembly work can be performed at a low cost. In addition, a series of operations can be completed while the liquid crystal display panel is being transported, so it can be continuously performed for a large number of dismantling operations.

  As described above, the three embodiments of the present invention have been described with reference to the drawings. However, the specific configuration is not limited to these embodiments. For example, a pair of winding rollers is used to wind the polarizing plate. A take-up reel may be used. Further, a plurality of slits in the longitudinal direction may be put in advance with a cutter in order to make it easier to peel off the polarizing plate.

It is a model figure of the liquid crystal display panel used by this invention. It is a partially expanded perspective view of a polarizing plate. It is a figure which shows the peeling system of a polarizing plate, (a) is a process figure which gives a thermal load, (b) is a tape adhesion process figure, (c) shows the winding process figure of a tape. It is a perspective view which shows the process of cutting off a sealing member with a cutter in the liquid crystal display panel from which the polarizing plate was isolated, (a) shows the state which cuts off two opposing sides of a rectangular panel, (b) is rectangular The state which cuts off two other opposing sides of a shape panel is shown, (c) is a schematic front view which shows the cutting position of FIG.4 (b). It is process drawing which shows the state which wash | cleans the inscribed surface side of the isolate | separated glass substrate. It is a perspective view which shows the process of grind | polishing the liquid crystal side inner surface of the glass substrate from which the sealing member was deleted with a diamond wheel. It is a peeling process figure of a polarizing plate. It is a grinding process figure of isolation | separation of a glass substrate, and a display element structural material. It is sectional drawing explaining the schematic structure of the conventional liquid crystal display panel. It is a top view which shows the peeling method of the conventional polarizing plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal display panel 12 Spacer 14,16 Glass substrate 18 Sealing member 20 Liquid crystal material 22 Display element constituent material 30 Polarizing plate 33 Release film 34 Adhesive layer 35, 37 Substrate film 36 Polarizing film 38 Protective film 40 Peltier cooler
40a Cooling plate surface 42 Tape 44, 46 Winding roller 50 Liquid crystal display panel 51 with polarizing plate peeled off Liquid crystal display panel 53 with two sides cut off Spreader 54 Diamond wheel 60, 62, 68 Conveyors 70, 74, 78 Conveyor 63 Holding rod 64 Vacuum suction devices 66 and 76 Mounting table 72 Turntable

Claims (6)

  In a liquid crystal display panel having a pair of glass substrates enclosing and holding a liquid crystal material inside by a seal portion, and a polarizing plate affixed to the outer surface of the pair of glass substrates with an adhesive, the affixed with the adhesive A polarizing plate peeling system for a liquid crystal display panel that peels a polarizing plate from a glass substrate, and a step of reducing the adhesive strength of the pressure-sensitive adhesive and a tape with an adhesive on one end side of the polarizing plate after the pressure-sensitive adhesive strength is reduced A polarizing plate peeling system for a liquid crystal display panel, comprising a step of bonding and a step of winding up the bonded tape.   The polarizing plate peeling system for a liquid crystal display panel according to claim 1, wherein the step of reducing the adhesive strength of the adhesive is means for applying a heat load to the adhesive.   The polarizing plate peeling system for a liquid crystal display panel according to claim 1, wherein the adhesive strength of the adhesive is greater than the adhesive strength of the reduced adhesive.   4. The polarizing plate peeling system for a liquid crystal display panel according to claim 1, wherein the step of winding the tape includes means for rotating the roller by sandwiching the tape between a pair of rollers.   A liquid crystal display panel reuse method for reusing a liquid crystal display panel from which a polarizing plate has been peeled off by the polarizing plate peeling system for a liquid crystal display panel according to any one of claims 1 to 4, wherein the seal portion is a cutter. A method for reusing a liquid crystal display panel, wherein the glass substrate is separated into two glass substrates, the inner surfaces of both glass substrates are ground with a diamond wheel, and the glass substrate and the display element constituent material are separated.   The method for reusing a liquid crystal display panel according to claim 5, wherein the liquid crystal display panel is peeled off, the glass substrate is separated, and the display element constituent material is ground while the liquid crystal display panel is transported to a transport device.

Images