WO2006054510A1

WO2006054510A1 - Resin extruded plate for optical use and method for manufacturing same

Info

Publication number: WO2006054510A1
Application number: PCT/JP2005/020819
Authority: WO
Inventors: Yoshikazu Tsuruta; Shunji Kamiya
Original assignee: Asahi Kasei Chemicals Corporation
Priority date: 2004-11-19
Filing date: 2005-11-14
Publication date: 2006-05-26
Also published as: KR20070074630A; JPWO2006054510A1; CN101060966A; TW200630202A

Abstract

Disclosed is a resin extruded plate for light guide plates which is suitable for displays used in office automation equipment such as personal computers and word processors, various monitors for displaying image signals such as panel monitors and television monitors as well as displays or advertising displays used in illuminating devices for indoor or outdoor spaces. Specifically disclosed is a resin extruded plate which is characterized in that it comprises surface protection films bonded to both sides of a plate having a thickness of 2-15 mm, there is no cutting dust having a size of 0.1 mm2 or more on the films, and there is no recess and/or dent having a size of 0.1 mm2 or more in the plate surface. Also disclosed is a method for manufacturing such a resin extruded plate.

Description

Specification

Optical resin extrusion plate and manufacturing method thereof

Technical field

[0001] The present invention relates to a liquid crystal display used as a display device such as a notebook or desktop personal computer, a portable information terminal, a game machine, a workstation, an image monitor, or a television, and also illuminates the liquid crystal with a back force. The present invention relates to a resin extruded plate suitable for a light guide plate used in a backlight device. Furthermore, the present invention relates to a method for producing a resin extruded plate suitable for a light guide plate suitable for producing a backlight device that does not impair the luminance and image quality of a liquid crystal display.

Background art

[0002] CRTs, so-called CRTs, have long been used as information and image display devices. In recent years, there has been a tendency for liquid crystal displays to replace cathode ray tubes in response to demands for thinner and smaller display devices. In a liquid crystal display, the liquid crystal unit itself does not have a function to emit light, so in general, V, a so-called knock light device is used that visually illuminates the display by illuminating the liquid crystal unit.

[0003] As a method of this backlight device, 1) a so-called direct type in which a “diffuser plate” having a function of scattering light is sandwiched between a light source and a liquid crystal unit, and 2) an edge of a light guide plate Two types of edge light systems are usually used, which use a reflector behind the light guide plate to emit light in the surface direction. At present, the edge light system is the mainstream. In particular, in recent years, development has continued under the concept of brighter, larger and thinner products, which are increasingly required to increase the brightness, size and thickness of display devices. In particular, there is a strong demand for the development of a backlight device with high brightness using the edge light method.

[0004] For this reason, for the light guide plate used in the backlight device, there is an extremely strong demand for a light guide plate that efficiently emits incident light incident from a light source lamp disposed on the side surface to the output surface. It is summer.

[0005] In response to such demands, a plurality of technical disclosures have been made so far regarding the method of increasing the brightness using a light guide plate. For example, Japanese Patent Publication No. 39-1194 discloses a light guide plate. JP-A-4-145485 discloses a method for obtaining a uniform light emitting surface by dispersing and mixing light diffusing particles. By using a light-scattering plastic material including fine particles having different refractive indexes as a light guide. Although a method for increasing the brightness is disclosed, the process is complicated.

[0006] However, in addition to the technology using methacrylic resin containing these complicated fine particles, the level can sufficiently meet the demands associated with the increase in size and thickness of display devices, such as brightness and luminance spots. It is the current situation that has been reached.

[0007] In addition, a resin extruded plate for a light guide plate is generally a saw blade in order to have a predetermined width and length after a surface protective film is attached to the front and back so that the surface of the plate is not scratched. Because it is cut with, it is easy for the chips to adhere to the surface protection film. The produced resin extrusion board is loaded on a pallet and stored and transported. As a result, the chips adhering to the surface protection film are pressed by the weight of the stacked plates, causing dents on the surface of the plates, and in severe cases, breaking the surface protection film and causing scratches on the surface of the plates. Cause. In particular, in the case of a resin extruded board exported overseas, the chips on the board are likely to damage the surface protection film due to the shaking of the ship being transported, and the surface of the board tends to be dented or damaged.

[0008] When dents or dents due to chips occur on the surface of the light guide plate, the light incident on the light source lamp force is scattered at the dents or dents on the surface to form so-called bright spots, which lowers the luminance. Furthermore, if there are many dents and scratches, it will be a malfunction when viewed on the LCD screen.

[0009] In the first place, the method of cutting a resin extruded plate that does not generate chips is as follows: 1) Shear cutting machine that cuts the blade by pressing one side or both sides of the plate, 2) A device that cuts with a laser beam, 3 ) A device that cuts with a water jet. However, all of these devices require a large force if the equipment is large and expensive. 1) Shear cutting machines have a large running cost due to blunting of the blades and immediate replacement of the blades. 2) Laser cutting machines Especially in the case of thick plates, the cutting surface is not clean, and the running cost for replacing the reflecting mirror where molten resin mist adheres to the plate is large. There are problems such as not getting clean.

[0010] The method of cutting the resin board with a saw is most suitable for stable production, but until now, a method of strictly removing the generated chips has been ineffective. Cutting that adheres to the surface protection film after cutting the resin board Even if the powder is blown away with the nozzle force or compressed air, it is not possible to strictly remove fine chips of about 0.1 mm ²

If it is difficult, the chips once blown off by force may reattach to the surface protection film. Even when a suction nozzle is installed on the front and back of the board to remove it, it is difficult to suck up fine chips sufficiently.If the suction is too strong, the board itself will be sucked, which will impede stable production. Become.

[0011] Although there is a method of increasing the thickness of the protective film to, for example, 90 microns or more so that the surface of the plate does not become dented or scratched even if chips adhere, it is difficult to completely prevent it. .

Patent Document 1: Japanese Patent Publication No. 39-1194

Patent Document 2: JP-A-4-145485

Disclosure of the invention

Problems to be solved by the invention

[0013] An object of the present invention is to provide a resin-extruded plate suitable for a light guide plate of a high-luminance edge light type backlight device for a liquid crystal display and having no chip adhesion.

Means for solving the problem

[0014] As a result of intensive investigations to solve the above-mentioned problems, the inventors of the present invention achieve high brightness of the knocklight device by strictly removing the chips on the surface protective film of the plate. As a result, the present invention has been completed.

That is, in the present invention, a surface protective film is applied to the front and back of a plate having a plate thickness of 2 to 15 mm.

,榭脂extrusion plate, characterized in that there is no 0. 1 mm ² or more the size of the chips is the size of the 0. 1 mm ² or more further plate surface Mugu depressions and Z or push scratches on the film And a manufacturing method thereof.

The invention's effect

[0016] The resin extruded plate of the present invention can maximize the luminous efficiency of the light incident upon the light source lamp force with no bright spots derived from chip adhesion.

Brief Description of Drawings

[0017] Fig. 1 shows an example of a chip suction rotary brush according to the present invention. FIG. 2 shows thickness measurement points in the present invention.

FIG. 3 shows an example of a bright spot evaluation method in an edge light type liquid crystal light source device using the light guide plate of the present invention.

FIG. 4 shows an example of a luminance evaluation method in an edge light type liquid crystal light source device using the light guide plate of the present invention.

FIG. 5 shows an example of a production facility for a resin extruded plate according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] The present invention will be specifically described below.

[0019] The resin-extruded plate of the present invention can be produced by melt-extruding a raw material resin to form a plate. Raw material resin includes methacrylic resin (PMMA), polystyrene (PS), styrene Z-methylmethalate resin (MS), acrylonitrile Z styrene resin (SAN), polycarbonate (PC), amorphous polyester Any alicyclic polyolefin (such as Mitsui Petrochemical's APO, Nippon Zeon's ZEONEX and ZEONOR, JSR's ARTON, etc.) can be used as long as it is transparent and melt-moldable. In addition, even if the raw material is used alone, it is mixed with additives such as light diffusing agents, fluorescent brighteners, ultraviolet absorbers, antioxidants, plasticizers, mold release agents, dyes, pigments, etc., as long as the brightness is not lowered. May be used. The plate may be produced by extruding as a single layer, or may be laminated into two or more layers by a coextrusion method or a laminating method.

[0020] Among the raw material resin, methallyl resin, polycarbonate, or alicyclic polyolefin is suitable as a raw material for the light guide plate in terms of transparency. Among them, methacrylic resin is colorless and transparent, light resistance, molding processability In view of properties such as mechanical strength and surface hardness, it is particularly preferably used.

[0021] The methacrylic resin that can be used particularly preferably in the present invention is, for example, 70% by weight or more of methyl methacrylate and Z or ethyl methacrylate, and less than 30% by weight of monomers having copolymerizability with these. Can be obtained by copolymerization. Examples of the copolymerizable monomer include propyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, tricyclodecyl methacrylate, phenol, methacrylate, and methacrylic acid. Methacrylic acid esters such as benzyl, methyl acrylate, acrylic Acrylate esters such as ethyl acid, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, tricyclodecyl acrylate, acrylic acid phenyl, benzyl acrylate, methacrylic acid Powers including unsaturated acids such as acid and acrylic acid, maleic anhydride, maleimide and the like are not limited to these. These monomers may be used alone or in combination of two or more.

[0022] The resin used as the raw material for the resin extruded board according to the present invention can be obtained by any polymerization method such as suspension polymerization, emulsion polymerization, cast polymerization, continuous bulk polymerization, and continuous solution polymerization. Can also be used. In particular, a resin manufactured using a suspension polymerization method and a continuous solution polymerization method, particularly a methallyl resin, is preferable as a raw material resin for a light guide plate with less interstitial material.

[0023] A suspension polymerization method of a methacrylic resin as an example of a raw material will be described. First, a polymerization initiator and a chain transfer agent are uniformly dissolved in a monomer mixture composed of methyl metatalate and Z or ethyl methacrylate and another copolymerizable monomer. The homogeneously dissolved product is suspended in an aqueous medium containing a dispersion stabilizer and then held at a predetermined polymerization temperature for a certain period of time to complete the polymerization. The resulting turbid polymer is filtered, washed with water and dried. Can be obtained.

[0024] Examples of the polymerization initiator used in suspension polymerization include radical polymerization initiators known for polymerization of vinyl monomers. For example, azobisisobutyl-tolyl, 2,2,1azobis (2,4 dimethylvaleronitrile), dimethyl-1,2,2'-azobisisobutyrate, t-butyl peroxypivalate, t-butyl peroxy 2- Examples include ethinorehexaate, tamperoxy 2-ethyl hexanoate, benzoyl peroxide, lauryl peroxide, and the like. The amount of these polymerization initiators used is preferably in the range of usually 0.01 to 2.0 parts by weight per 100 parts by weight of the monomer or monomer mixture.

[0025] The chain transfer agent used in the suspension polymerization may be a known one used for the polymerization of methyl methacrylate. Examples thereof include t-butyl mercaptan, n-butyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan and the like. The amount of these chain transfer agents used is usually preferably in the range of 0.01 to 2.0 parts by weight per 100 parts by weight of the monomer or monomer mixture. [0026] The dispersion stabilizer used in the suspension polymerization is not particularly limited, but is a poorly water-soluble inorganic compound such as calcium phosphate, calcium carbonate, aluminum hydroxide or the like, polybutyl alcohol, polyethylene oxide, cellulose. Nonionic polymer compounds such as derivatives, polyacrylic acid and its salts, polymethacrylic acid and its salts, copolymer of methacrylic acid ester and methacrylic acid and its salts, etc. I can do it. The amount of these dispersion stabilizers used is preferably in the range of 0.01 to 5.0 parts by weight per 100 parts by weight of water.

[0027] Examples of water used in suspension polymerization include pure water, ion-exchanged water, and deionized water. The amount of water used is not particularly limited, but is preferably in the range of 100 to 300 parts by weight per 100 parts by weight of the monomer or monomer mixture! /.

[0028] The polymerization temperature of the suspension polymerization is not particularly limited, but is about 60 to 120 ° C and a temperature suitable for the polymerization initiator used. As a polymerization apparatus, a polymerization vessel equipped with a well-known stirring blade, for example, a turbine blade, a fiddler blade, a propeller blade, a blue margin blade, or the like, is used, and the vessel is provided with a kaffle. Is common.

[0029] Further, if necessary, a light diffusing agent, an ultraviolet absorber, a fluorescent whitening agent, an antioxidant, a plasticizer, a release agent, a dye, a pigment, and the like may be suspended and polymerized.

After completion of the suspension polymerization, a spherical resin can be obtained (for example, a spherical methallyl resin) by washing, dehydrating and drying by a known method.

[0030] The average particle size of the spherical resin used as a raw material for the resin extruded plate according to the present invention is 0.2 to 0.5 mm, and preferably 0.25 to 0.39 mm. If it is less than 0.2 mm, good plate thickness accuracy cannot be obtained, and it is difficult to stably produce a polymer having an average particle diameter exceeding 0.5 mm.

[0031] The resin used as a raw material for the resin extruded plate in the present invention is a spherical resin obtained by suspension polymerization, and a spherical resin is supplied to an extruder equipped with a vent at a temperature of 220 to 260 ° C. Vent vacuum pressure of 10-60 torr. Extruded into strands from extrusion dies, cooled with water, cut into strand cutters (pellet-shaped), and known continuous solution polymerization method, continuous mass Use a cylindrical (pellet-shaped) resin obtained by extruding a molten resin polymer obtained by a state polymerization method into a strand from an extrusion die, water-cooling, and cutting with a strand cutter. The Examples of the continuous solution polymerization method and the continuous bulk polymerization method include the following methods. As a solvent in the continuous solution polymerization method, a monomer of a raw material resin (for example, a monomer capable of copolymerizing with a methyl methacrylate monomer, a methyl methacrylate monomer, and a methyl methacrylate at the bottom of the distillation column and inside the distillation column). More specifically, aromatic compounds such as toluene, xylene, ethylbenzene, and jetylbenzene, aliphatic compounds such as octane and decane, alicyclic compounds such as decalin, acetic acid, etc. Examples include esters such as butyl and pentyl acetate, and halogen compounds such as 1, 1, 2, 2-tetrachloroethane. In particular, alkylbenzene, and among them, toluene, xylene and ethylbenzene are preferable because they have appropriate boiling points, have less degassing load and do not adversely affect polymerization. The amount of the solvent varies depending on the boiling point of the solvent. The amount of the solvent is preferably 30% by weight or less, more preferably 25% by weight or less based on the weight of the total mixture at the time of polymerization. If no solvent is used during polymerization, bulk polymerization occurs.

[0032] The polymerization initiator used in the continuous solution polymerization method and the continuous bulk polymerization method can be a polymerization initiator that decomposes actively at the polymerization temperature to generate radicals. For example, di-t-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, di-t-butyl perphthalate, di-t-butyl perbenzoate, t-butyl peracetate, 2,5-dimethyl-2,5-di (t —Butylperoxy) hexane, 1,1bis (t-butylperoxy) (3,3,5 trimethyl) cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, di-tamilperoxide, Benzyl peroxide, cumene hydride peroxyside, lauryl peroxide, azobisisobutanol diacetate, 1,1, -azobiscyclohexanecarbonitryl, 2 phenylazole 2,4 dimethyl-4-methoxyvaleronitol, List 2-cyanose, 2,2-propylazoformaside, 2,2'-azobisisobutyryl-tolyl, etc. Can. The amount of these polymerization initiators used is preferably 0.001 to 0.03% by weight based on the weight of the total reaction mixture.

[0033] Furthermore, mercabtans are mainly used as the molecular weight regulator used in this case. Examples of the mercaptans include n-butyl mercaptan, isobutyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, sec dodecyl mercaptan, t-butyl mercaptan, felt mercaptan, tiocresol, thioglycolic acid and the like. Examples thereof include esters and ethylenethioglycol. The amount of these molecular weight modifiers used is preferably 0.01 to 0.5% by weight based on the weight of the total reaction mixture.

[0034] The polymerization reactor uses a device that is uniformly stirred by a stirring blade such as a double helical ribbon or a pitched paddle type. In the polymerization, the monomer or monomer solution is continuously supplied to the polymerization reactor, and the polymerization conversion rate of the monomer is substantially constant within a range of 0 to 70%. The polymerization reaction is carried out at a temperature of 160 ° C. If the polymerization conversion rate is less than 40%, the load of the devolatilization process due to the volatile component is large. For example, the devolatilization may become insufficient due to the restriction of the heat transfer area of the preheater. On the other hand, if it exceeds 70%, for example, the polymerization reaction power is not preferable because the piping pressure loss between the preheaters becomes large and the transport of the polymerization liquid becomes difficult. If the polymerization temperature is less than 120 ° C, the polymerization rate is too slow to be practical, and if it exceeds 160 ° C, the polymerization rate is too high and it is difficult to adjust the polymerization conversion. Further, the heat degradability is lowered, which is not preferable.

[0035] The polymerization solution obtained by such a polymerization reaction is devolatilized and the polymer is taken out. As the devolatilizer, an extruder with a multistage vent, a devolatilization tank, etc. are used. Preferably, the polymerization liquid is heated to a temperature of 200 to 290 ° C with a pre-heater or the like, has a sufficient space at the top, and 200 to 250 ° C, 20 to: LOO Torr temperature, under vacuum Feed the devolatilization tank to remove the polymer.

This polymer is continuously transferred to an extruder in a molten state, extruded through a die from a die into a strand, cooled with water, and cut with a strand cutter to obtain a cylindrical polymer.

[0036] Further, if necessary, before extruding into a strand from a die, using a feed pump from the side part of the extruder, a light diffusing agent, an ultraviolet absorber, a fluorescent whitening agent, an antioxidant, a plasticizer , Mold release agents, dyes, pigments and the like may be added.

[0037] The resin extruded plate of the present invention can be produced by a melt extrusion molding method. For example, raw resin is melted in an extruder, extruded from T-Dieka, and passed through three, four to five temperature controlled rolls, and formed into a plate shape (preferably a flat plate shape). The molded plate is cooled and solidified while being drawn with a take-up roll through a guide roll, and a resin extruded plate can be obtained as a single-wafer product by cutting the width direction and the flow direction into predetermined lengths. it can. At this time, the force capable of producing a resin extruded plate having a desired thickness by adjusting the gap between the polishing rolls and the take-off speed Generally, a resin extruded plate having a thickness of 2 to 15 mm is used for the light guide plate.

[0038]榭脂pushing plate of the present invention, no metal chips 0. 1 mm ² or more in size to the surface of the surface protective film is the most important property as the light guide plate. If the chips are attached, the resin board is loaded, and further, the chips are pressed against the surface protection film by the weight of the stacked boards when transporting, creating a dent on the surface of the resin board. Or break the film and cause scratches

[0039] In order to strictly remove the chips adhering to the surface protective film, the present inventors cut the resin extrusion plate with a saw, and then suck the chips while brushing the surface protective film with a rotating brush. We have found that removal is extremely effective.

[0040] In the present invention, the rotating brush is brought into contact with the surface protective film of the resin extruded plate. The material of the brush filament has moderate elasticity, flexibility and wear resistance, and the surface protective film. There is no particular limitation as long as it does not hurt or turn off the resin board. In addition to synthetic fibers such as polypropylene and nylon, natural fibers derived from plants or animals can also be used. In order to prevent the generation of static electricity, it is preferable to use conductive synthetic fibers. It is important that the rotating brush is in contact over the entire width of the board. There is no particular limitation on the rotation speed, but generally it is preferably in the range of 100 to 1000 rpm. It is extremely important that the suction device incorporates a rotating brush and sucks immediately after the surface of the plate is brushed to remove chips. When the rotating brush and the suction device are installed separately, the effect of the present invention cannot be obtained sufficiently. A suction force of 5 kPa or more is sufficient to remove normal chips. (See Fig. 1 of the present invention. A is a rotating brush, B is a suction device cover, C is a resin extrusion plate, D is a suction duct, and an arrow from C indicates an extrusion direction.) Also, a surface protective film In order to remove the chips adhering to the surface, it is extremely effective to pass the cut plate between the two upper and lower adhesive rolls to adhere and remove the chips adhering to the surface protective film. I found it. In this case, the adhesive roll can be used to stick and remove chips by kneading or applying an adhesive material such as ethylene Z vinyl alcohol on the surface of elastic materials such as polyurethane and synthetic rubber. If there is no limit Can be used. In addition, the roll 1 for directly adhering to and removing the chips by directly contacting the surface protective film is brought into contact with the roll 1 with 2 more strong adhesive rolls. Move and devise so that the surface of roll 1 is kept clean.

[0041] [Example]

A more specific description will be given based on examples of the present invention. First, each measuring method about the resin extruded board which concerns on a present Example is shown below.

[0042] (Measurement of thickness of extruded resin plate)

In the 1000 mm wide resin extruded board 1 shown in Fig. 2, the thickness was measured up to 0. Olmm using the outer micrometer (MDC-25M manufactured by Mitutoyo Corporation) as the thickness measurement point 2 in the width direction. Averaged. The thickness of the extruded resin plate 1 in the extrusion direction (in the direction of the arrow in FIG. 1) was measured in the same manner as the plate thickness measurement point 3 at intervals of 50 mm over the length of 1000 mm at both ends of the plate.

[0043] (Measurement method of bright spot of light guide plate)

In accordance with the light source device shown in Fig. 3, a cold cathode tube (made by Harrison Electric) with a diameter of 3 mm is installed on one side of the light guide plate C as the light source A in the lamp house B. Ray White 75 (made by Kimoto) is used as the reflective sheet D, and the cold cathode tube is visually observed by applying a voltage of 12 V from a DC voltage stabilizer, and the number of bright spots of 0.1 mm ² or more is observed. To do. Measure 10 samples and get the average value.

(Measurement method of brightness of light guide plate and brightness spots)

In accordance with the light source device shown in Fig. 3, as the light source A in the lamp house B, a cold-cathode tube of 3mmφ (made by Harrison Electric) is installed on both end faces of the light guide plate C on the length side of 319mm, and the light reflecting sheet D Ray white 75 (manufactured by Kimoto) was used as the light diffusion plate E, and two D121 (manufactured by Gidden) were placed on the light guide plate. The cold cathode tube was charged with a voltage of 12V from a DC voltage stabilizer, and after 20 minutes of lighting, a luminance meter (CA-1000: manufactured by Minolta) placed at a distance of 1 lm from the light emitting surface was used to make the entire light emitting surface 19 X horizontal The luminance of each of the measurement points divided into 19 = 361 was measured. Next, the obtained measurement power of 361 points also calculated the average luminance.

[0044] In addition, the obtained measured value force of 361 points was also used as an evaluation index for luminance spots by the following [Equation 1]. The degree was calculated.

[0045] [Formula 1]

Uniformity (%) = Minimum luminance value Z Maximum luminance value X 100

(Measuring method of average particle diameter of spherical metataryl rosin polymer)

An electromagnetic shaking sieving meter (electromagnetic vibration AS200 DISIT manufactured by Mitamura Riken Kogyo Co., Ltd.) was used. Sample lOOg is placed on the top sieve of 0.5 ~ 0.15mm 7-stage force, shaken with a shaker for 10 minutes, and the spherical methacrylic resin polymer on each sieve is weighed, and the cumulative residual distribution curve is obtained. Writing, the median diameter was determined and taken as the average particle diameter.

[0046] (Measuring method of major axis, minor axis, length of cylindrical methacrylic resin)

Using an outer micrometer (MDC-25M manufactured by Mitutoyo Corporation), the major axis, minor axis, and length of 200 samples were measured to 0.001 mm, and the average value was determined.

(Production of Spherical Metataryl Resin Polymer (Polymer-A))

95.0 parts by weight of methyl methacrylate, 5.0 parts by weight of methyl acrylate, 0.15 parts by weight of lauroyl peroxide, 0.25 parts by weight of n-octyl mercaptan, 130 parts by weight of deionized water, 00.65 parts by weight of aluminum was put into a 200-liter polymerization machine and mixed with stirring. Suspension polymerization was carried out at a reaction temperature of 80 ° C for 150 minutes, followed by aging at 100 ° C for 60 minutes to complete the polymerization reaction. Next, the polymerization reaction solution is cooled to 50 ° C, diluted sulfuric acid is added, washed and dehydrated and dried, and melt flowlay HISO 1139 Condi 3) 1. Spherical methacrylic resin with OgZlO content (polymer A) Got. The average particle diameter of the polymer A was 0.39 mm.

[0047] (Production of cylindrical methacrylic resin (polymer B))

1,1-bis (t-butylperoxy) -3,3,5-trimethyl in a monomer mixture consisting of 79.9% by weight methyl methacrylate, 5.1% by weight methyl acrylate, and 15% by weight ethylbenzen Add 150ppm of cyclohexane and 300ppm of n-octyl mercaptan and polymerize in a fully mixed polymerization reactor at a polymerization temperature of 155 ° C and a residence time of 2.0 hours. The liquid was continuously removed from the polymerization reactor, then heated to 260 ° C. with a heating plate, and cast and dropped through the space between the heating plates. The devolatilization tank was maintained at 30 torr and 230 ° C, and the polymer was separated from the unreacted monomer and solvent. The polymer is continuously transferred to the extruder in a molten state, and is pushed into a strand from the die through the extruder. It is cooled with water (60 ° C water bath) and cut with a strand cutter to obtain a melt flow rate (ISO 1139 Condl3) l. OgZlO-containing cylindrical methacrylic resin (polymer B) It was. Polymer — B's major axis (a), minor axis (b), and length (L) are (a) 2. 773mm, (b) 2. 689mm, (L) 3. 105mm, (b) / ( a) 0.97.

Example 1

[0048] A mixture of 50 parts by weight of polymer A and 50 parts by weight of polymer B (total 100 parts by weight) is fed to the raw material hopper in Fig. 4, and the cylinder temperature is 210, 210, 240 in order of the hopper side force to the die side. 250, 260, 260. 150mm φ single screw extruder 2) melted by C, temperature adjusted to 1250mm with lip width of 1250mm, lip opening of 10mm Passed between 4 arranged 4) poly cinder rolls (temperature is 89, 94, 95, 95 ° C in order), 5) cooled while pulling the extruded plate on the guide roll with 6) take-up roll . The temperature around the extrusion line was 49 ° C. A fan and air blowing device are provided above and below the guide roll to cool the front and back of the plate. By adjusting these, the temperature distribution of the center and edges of the plate and the front and back are controlled, and there is little warpage. A fat extrusion board is manufactured.

[0049] A polyethylene masking (90 microns thick) made of Daio Power Paper for surface protection was pasted on the top and bottom of the board at the take-up roll section, and 7) both ends of the board were cut to a width of 1100 mm with a trimming machine. 8) Cut to 1380mm length with a cross-cut machine to make a single sheet, and then pass through the top and bottom 9) chips suction rotating brush (500rpm, suction force 7kPa), 10) feed to conveyor 11) stacker 13) A predetermined number of sheets were loaded on the pallet 12) as light guide plate products. Defective plates were not stacked on the pallet, and 14) discharged to defective dispensing so that they were not mixed into the product. The plate thickness was measured and found to be 6.00 ± 0.05 mm.

[0050] In this way, a resin extruded plate A having a thickness, width and length of 6 x 1100 x 1380 mm was obtained. When this was observed, chip adhesion of 0.1 mm ² or more on the front and back sides was helpless.

[0051] 100 sheets of this resin extrusion board were loaded on a pallet, and Fujioka in Shizuoka Prefecture was also transported to Busan City, South Korea by truck and ship. After removing the packaging and the surface protection film, even when observed, no dents or scratches of 0.1 mm ² or more were observed. This resin extruded plate was cut to a size of 6 X 150 X 300 mm and measured for a bright spot.

[0052] Next, use a circular saw with a size of 241mm in width and 319mm in length from the extruded resin board A after transportation. Then, the cut surface of the cut plate is polished with a precision polishing machine (PLA—Beauty: manufactured by Megalotech-Power Co., Ltd.), further puffed and finished to a mirror surface, and then 15 inch size dots Using a printing screen with gradation, using Mattmedium SR 931 (manufactured by Mino Group) as ink, screen printing was performed on one side of the light guide plate to obtain a light guide plate. As a result of measuring the luminance, it was 2900 cd. These results are shown in Table 1.

Example 2

[0053] A resin extruded plate B was obtained in the same manner as in Example 1 except that the chips were sandwiched between two upper and lower adhesive rolls and the chips were removed by suction without using the chip suction rotating brush. Table 1 shows the measurement results of dents or dents, chips, bright spots and brightness.

[Comparative Example 1]

A resin extruded plate C was obtained in the same manner as in Example 1 except that the chip suction rotary brush was not used and only the front and back sides of the board were sucked with a suction force of 7 kPa. Table 1 shows the measurement results of dents or dents, chips, bright spots and brightness.

[Comparative Example 2]

A resin extruded plate D was obtained in the same manner as in Example 1 except that the chip suction rotating brush was not used and only the front and back of the plate were blown with compressed air. Table 1 shows the measurement results of dents or dents, chips, bright spots and brightness.

[0054] [Table 1]

[0055] (Summary of results) As shown in the above examples and comparative examples, when the chip suction rotating brush and the adhesive roll of the present invention are not used, chips remain on the surface protective film of the resin board, and after transportation on land and sea. Since the surface of the plate has dents and scratches, and generation of bright spots and a decrease in luminance are observed, it is not preferable as a light guide plate for a knock light unit.

Industrial applicability

The resin extruded plate of the present invention is used for a liquid crystal display as a display device such as a notebook or desktop personal computer, a portable information terminal, a game machine, a workstation, an image monitor, or a television. It can be suitably used as a light guide plate used in an illuminating backlight device.

Claims

The scope of the claims

[1] A surface protective film is applied to the board, there is no chip of 0.1 mm ² or more on the film, and there are dents of 0.1 mm ² or more and Z or scratches on the surface of the board. No rosin extrusion board.

[2] The resin extruded plate according to claim 1, wherein the raw material resin is a methacrylic resin, a polycarbonate, or an alicyclic polyolefin.

[3] The raw material resin is spherical metataryl resin, and the average particle size is 0.2 to 0.5 mm.

1. The resin extruded board according to 1.

[4] The resin extruded plate according to claim 1, wherein the plate thickness is 2 to 15 mm.

[5] Extruded into a plate shape using molten resin, cooled and solidified while pulling the formed plate through the take-up roll with a take-up roll, and pasted the surface protection film on the front and back, then the width direction and flow In the method of manufacturing a resin extruded plate that cuts the direction to a predetermined length, there is no swarf on the surface protective film by sucking and removing the chips while brushing the surface protective film with a rotating brush after cutting. A method for producing a resin extruded plate.

[6] Extruded into a plate shape using molten resin, cooled and solidified while pulling the formed plate through the take-up roll with the take-up roll, and pasted the surface protection film on the front and back, then the width direction and flow In a method for producing a resin extruded plate that cuts the direction to a predetermined length, the cut plate is passed between two upper and lower adhesive rolls to adhere and remove the chips adhering to the surface protective film. A method of producing a resin-extruded plate that eliminates chips on the protective film.

7. The method for producing a resin-extruded plate according to claim 5 or 6, further comprising a step of forming a plate by sequentially passing between 3 to 5 polishing rolls adjusted in temperature.