WO2007094209A1 - Procede de fabrication de plaque plate moulee, et plaque plate moulee - Google Patents

Procede de fabrication de plaque plate moulee, et plaque plate moulee Download PDF

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Publication number
WO2007094209A1
WO2007094209A1 PCT/JP2007/052089 JP2007052089W WO2007094209A1 WO 2007094209 A1 WO2007094209 A1 WO 2007094209A1 JP 2007052089 W JP2007052089 W JP 2007052089W WO 2007094209 A1 WO2007094209 A1 WO 2007094209A1
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WO
WIPO (PCT)
Prior art keywords
gate
row
gates
gate row
cavity surface
Prior art date
Application number
PCT/JP2007/052089
Other languages
English (en)
Japanese (ja)
Inventor
Masahiko Hayashi
Noboru Muraoka
Kazunori Ueki
Original Assignee
Zeon Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zeon Corporation filed Critical Zeon Corporation
Priority to JP2008500453A priority Critical patent/JPWO2007094209A1/ja
Publication of WO2007094209A1 publication Critical patent/WO2007094209A1/fr

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Classifications

    • 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
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/26—Moulds
    • 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
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0046—Details relating to the filling pattern or flow paths or flow characteristics of moulding material in the mould cavity
    • 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
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/76—Measuring, controlling or regulating
    • 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
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0025—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks
    • B29C2045/0032—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks sequential injection from multiple gates, e.g. to avoid weld lines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2007/00—Flat articles, e.g. films or sheets

Definitions

  • the present invention relates to a method for producing a flat plate molded product and a flat plate molded product produced by the production method.
  • a backlight device for a liquid crystal display an edge light type method or a direct type method is used.
  • a general direct type backlight device includes a plurality of light sources arranged in parallel, a reflection plate that reflects light emitted from the light source, light from the light source and light reflected by the reflection plate. And a light diffusing plate for diffusing irradiation
  • the light diffusing plate used in such a direct type backlight device is often molded by an extrusion molding method, a casting method, an injection molding method, or the like.
  • Japanese Patent Application Publication No. 20 05-271306 discloses a method of forming a light diffusion plate by an injection molding method. In this method, a rectangular cavity surface is divided into predetermined rectangles, and a light diffusing plate is manufactured by using a mold in which a gate is provided at the center in the short direction from the intersection of diagonal lines of each rectangle. It is. According to such a method, since air does not easily accumulate in the cavity, there is an effect that it is possible to efficiently manufacture a high-quality light diffusing plate with less appearance defects due to burning or the like.
  • An object of the present invention is to provide a method for producing a flat plate product capable of efficiently producing a high quality flat plate product while keeping the pressure inside the mold low, and a flat plate product obtained by this production method. It is to provide.
  • a method for manufacturing a flat plate molded product capable of efficiently manufacturing a high quality flat plate molded product while suppressing the internal pressure when a plurality of gates are arranged at equal intervals in the vertical direction and the horizontal direction, respectively. I found it.
  • a method for manufacturing a resin-made flat plate molded article using an injection mold wherein the mold is the flat plate molded article.
  • a substantially rectangular cavity surface corresponding to the shape of the cavity surface is formed, and a fixed mold plate provided with a plurality of gates communicating with the cavity surface is provided, and the plurality of gates are substantially rectangular longitudinally of the cavity surface.
  • the substantially rectangular cavity surface is arranged at the position of the intersection of the grids.
  • the distance LA1 to LA4 between each outermost gate and the nearest side among the lateral sides of the cavity surface is 120% to the pitch L1.
  • 10% and each outermost gate and the cavity surface are 120% to 10% of the pitch L2, and the plurality of gates are a plurality of gates arranged in the vertical direction.
  • the number of gate rows in at least one of the number of the vertical gate rows and the number of the horizontal gate rows as a plurality of horizontal gate rows comprising a vertical gate row and a plurality of gates arranged in the horizontal direction Is an odd number, and in the gate row in any direction where the odd number is present, the first gate row is a row including a plurality of gate rows and a central gate that is a gate closest to an intersection of diagonal lines of the cavity surface.
  • Each gate row close to each gate row that makes up the row The n-th gate column that contains ( n is an integer greater than or equal to 2), and the first step of injecting the resin from the first gate row, and when the injection amount of the n-1 gate row force reaches a predetermined amount, the nth gate row
  • a method of manufacturing a molded article is provided.
  • the center gate row becomes the first gate row, and the gate closest to the first gate row.
  • the second gate row which is a row, will contain two gate rows, one on each side of the first gate row.
  • there is one gate row that is the closest to each gate row force that constitutes the second gate row so there are also two third gate rows. After that, there will be two gate rows for every nth gate row.
  • the resin is fed from the central gate row (first gate row).
  • the first gate row force is also injected from the first step of injecting the resin, and then from each gate row (second gate row) on both sides of the first gate row.
  • the number of gate columns is 2n-l (where n is an integer equal to or greater than 2)
  • the first gate row including the central gate is formed in the order of the first gate row in the direction of the odd number of rows.
  • the timing of the resin injection is shifted in the order of this gate row, so that even if the gates are arranged approximately at the intersections of the lattice, there is no air pool in the cavity. It is possible to prevent appearance defects such as burning due to air accumulation. This makes it possible to produce high-quality flat plate products.
  • the plurality of gates are arranged substantially evenly in this way, it is possible to keep the internal pressure of the mold within which the pressure does not rise partially in the cavity.
  • the number of gate rows is, for example, 4 in the vertical direction, 3 in the horizontal direction, 3 in the vertical direction, 3 in the horizontal direction, 2 in the vertical direction, 3 in the horizontal direction, and 4 in the vertical direction.
  • X can be 5 in the horizontal direction.
  • the direction of the odd number of columns may be either the vertical direction or the horizontal direction. However, the direction of the odd number of columns is preferably the longer one of the vertical direction and the horizontal direction.
  • the distances LA1 to LA4 in the outermost gates may be substantially the same, and the distances LB1 to LB4 in the outermost gates may be substantially the same.
  • a method for producing a substantially rectangular flat plate molded article by injection molding a resin using an injection mold includes a movable mold plate and a fixed mold plate on which a substantially rectangular cavity surface corresponding to the shape of the flat plate molded product is formed and a plurality of gates communicating with the cavity surface are provided.
  • the plurality of gates have a pitch in the first direction along the first side of the substantially rectangular shape of the cavity surface is L1, and the second direction in the second direction along the second side orthogonal to the first direction.
  • the plurality of gates arranged at the intersections of the lattice and a plurality of first gate rows composed of a plurality of gates arranged along the first direction are arranged.
  • the two gate rows closest to the intersection of the diagonal lines of the cavity surface are the eleventh gate row and the twelfth gate row, and the two gates close to the eleventh gate row and the twelfth gate row.
  • the rows are the 13th gate row and the 14th gate row, respectively.
  • the two gate rows closest to the intersection of the diagonal lines of the cavity surface are the 21st gate row and the 22nd gate row.
  • each gate is expressed as (first gate row, second gate row), (13, 21), (11, 22), (12, 21), (14, 22) first group including gates (13, 22), (11, 21), (12, 22), (14, 21) a first step of injecting the resin from each gate included in any one of the second groups including each gate;
  • the injection amount in the first step reaches a predetermined amount
  • the second step of injecting the resin from each gate included in the other group and the injection amount in the second step become the predetermined amount.
  • a third step of injecting the resin from each gate of the 23rd gate row and the 24th gate row When the two gate rows close to the gate row and the 22nd gate row are respectively the second 3rd gate row and the 24th gate row, and each gate is expressed as (first gate row, second gate row), (13, 21), (11, 22), (12, 21), (14, 22) first
  • the plurality of gates are arranged in a substantially uniform manner in this way, the mold pressure within the cavity where the pressure does not partially rise can be kept low. Therefore, it is possible to manufacture a high-quality flat plate molded product more efficiently while keeping the in-mold pressure low.
  • a method of manufacturing a substantially rectangular flat plate molded article by injection molding a resin using an injection mold includes a movable mold plate and a fixed mold plate on which a substantially rectangular cavity surface corresponding to the shape of the flat plate molded product is formed and a plurality of gates communicating with the cavity surface are provided.
  • the plurality of gates have a pitch in the first direction along the first side of the substantially rectangular shape of the cavity surface is L1, and the second direction in the second direction along the second side orthogonal to the first direction.
  • the plurality of gates arranged at the intersections of the lattice and a plurality of first gate rows composed of a plurality of gates arranged along the first direction are arranged.
  • the two gate rows closest to the intersection of the diagonal lines of the cavity surface are the eleventh gate row and the twelfth gate row, and the two gates close to the eleventh gate row and the twelfth gate row.
  • the rows are the 13th gate row and the 14th gate row, respectively.
  • the two gate rows closest to the intersection of the diagonal lines of the cavity surface are the 21st gate row and the 22nd gate row.
  • the two gate rows close to the gate row and the 22nd gate row are the second gate row and the 24th gate row, respectively, and each gate is expressed as (first gate row, second gate row).
  • the first group including the gates of (11, 22) and (12, 21), and one of the second groups including the gates of (11, 21) and (12, 22).
  • the injection amount in the second step and the second step reaches a predetermined amount, the resin is discharged from each gate of the thirteenth gate row, the fourteenth gate row, the twenty-third gate row, and the twenty-fourth gate row.
  • the distance LA1 to LA4 between each outermost gate and the nearest side of the cavity surface in the second direction is 120% to 10% of the pitch L1, and each outermost gate and the cavity surface. It is preferable that the distances LB1 to LB4 with the closest side among the sides in the first direction are 120% to 10% of the pitch L2.
  • the distances LA1 to LA4 at the outermost gates are substantially the same, and the distances LB1 to LB4 at the outermost gates are substantially the same.
  • the method for producing a flat plate molded article of the present invention it is possible to satisfactorily inject grease into the vicinity of each apex of a substantially rectangular shaped cavity surface, and to produce a high-quality flat surface having no thickness unevenness.
  • a plate molded product can be manufactured more efficiently.
  • the number of the gates is N (pieces), and the depth of the cavity formed in the fixed mold is t.
  • the area of the cavity surface is S (mm 2 )
  • the fourth aspect of the present invention it is possible to provide a flat molded product having no appearance defect manufactured by the method for manufacturing a flat molded product of the present invention.
  • flat plate molded products include optical members such as a light diffusing plate and a light guide plate.
  • FIG. 1 is a plan view schematically showing a cavity surface formed on a fixed mold according to a first embodiment of the present invention.
  • FIG. 2 is a plan view for explaining the position of the gate formed on the cavity surface according to the first embodiment of the present invention.
  • FIG. 3 is a plan view of a cavity surface for explaining a method of manufacturing a light diffusing plate according to the first embodiment of the present invention.
  • FIG. 4 is a flowchart for explaining the procedure of the method for manufacturing the light diffusing plate according to the first embodiment of the present invention.
  • FIG. 5 is a plan view schematically showing a cavity surface formed on a fixed mold plate according to a second embodiment of the present invention.
  • FIG. 6 is a plan view for explaining the position of the gate formed on the cavity surface according to the second embodiment of the present invention.
  • FIG. 7 is a plan view of a cavity surface for explaining a method of manufacturing a light diffusing plate according to the second embodiment of the present invention.
  • FIG. 8 is a flowchart for explaining the procedure of a method for producing a light diffusing plate according to the second embodiment of the present invention.
  • FIG. 9 is a diagram for explaining a state of resin flow when manufacturing a light diffusing plate according to a second embodiment of the present invention.
  • FIG. 10 is a diagram for explaining a state of resin flow when manufacturing a light diffusing plate according to a second embodiment of the present invention.
  • FIG. 11 is a diagram for explaining a state of resin flow when manufacturing a light diffusing plate according to a second embodiment of the present invention.
  • FIG. 12 is a diagram for explaining gate opening / closing timings when the number of gates formed on the stationary mold plate according to the second embodiment of the present invention is 6 ⁇ 8.
  • FIG. 13 is a view for explaining the state of resin flow when manufacturing a light diffusing plate according to a third embodiment of the present invention.
  • FIG. 14 is a diagram showing a configuration of a liquid crystal display device according to an embodiment of the present invention.
  • FIG. 15 is a plan view schematically showing a cavity surface of a fixed mold in Comparative Example 2 as a conventional technique.
  • FIG. 16 is a plan view schematically showing the cavity surface of the fixed mold in Comparative Example 3 as a prior art.
  • FIG. 17 is a plan view schematically showing the cavity surface of the fixed mold plate in Comparative Example 4 as a conventional technique.
  • An injection mold is composed of a fixed mold (fixed mold plate) and a movable mold (movable mold plate), and injects grease into the cavity that is the gap between the fixed mold and the movable mold. Then, for example, a light diffusion plate that is a flat plate molded product is manufactured.
  • a gas vent is provided at the outer peripheral edge of the injection mold for releasing air in the cavity at the time of injection molding.
  • the fixed mold can be equipped with a hot runner or cold runner.
  • a vacuum drawing hole for releasing air in the cavity or the like can be provided in the fixed mold or the movable mold.
  • the depth of the cavity is preferably 0.1 mm to 15. Omm, more preferably 0.2 mm to 5. Omm. 0.5 nm! ⁇ 3. More preferably, it is Omm.
  • the key The depth of the cavity substantially coincides with the thickness of the obtained flat plate molded product.
  • FIG. 1 is a plan view schematically showing a cavity surface formed on a fixed mold.
  • the cavity surface 10 is formed in a substantially rectangular shape.
  • the rectangular vertex is 10A ⁇ : L0D
  • the vertical side connecting vertex 10A and vertex 10B is 11A
  • the vertical side connecting vertex IOC and vertex 10D is 11B
  • the horizontal side connecting vertex 10A and vertex 10C is 12A
  • the horizontal side connecting vertex 10B and vertex 10D is 12B.
  • the vertical direction is the vertical direction in FIG. 1, and the horizontal direction is the left-right direction in FIG.
  • the diagonal length of the cavity surface 10 is preferably 400 mm or more, more preferably 650 mm or more. According to the manufacturing method according to an embodiment of the present invention to be described later, even if the diagonal length is larger than the numerical value, a flat plate molded product with less thickness unevenness can be efficiently manufactured.
  • the entire cavity surface for example, (1) when the entire cavity surface is rectangular, (2) the entire cavity surface is a rectangular main body, and the main body The peripheral edge portion is formed in an arbitrary shape, and the entire cavity surface is not a rectangular shape.
  • the cavity surface 10 is usually formed so that the length in the horizontal direction is larger than the length in the vertical direction, but the length in the vertical direction and the length in the horizontal direction may be substantially the same.
  • FIG. 2 is a schematic diagram for explaining the position of the gate 20 on the cavity surface 10.
  • each gate 20 consists of a vertical line A along the vertical side ⁇ ⁇ ( ⁇ ⁇ ) of the cavity surface 10 and a horizontal line B along the horizontal side 12A (12B). Is considered at the position of the intersection P of the lattice.
  • This lattice is The vertical pitch (the pitch between the gates 20 arranged in the vertical direction) is L1, and the horizontal pitch (the pitch between the gates 20 arranged in the horizontal direction) is L2.
  • the plurality of gates are formed at substantially equal intervals along the vertical direction and the horizontal direction of the cavity surface 10.
  • substantially uniform intervals means that each interval falls within an error range of about 10% with respect to an average interval obtained by averaging all intervals in a certain direction.
  • the error range is preferably within a range of about 5%, more preferably within a range of about 1%.
  • the pressure inside the mold can be kept low, and the one with a small mold clamping force can be used.
  • the pitch L1 in the vertical direction can be 143.3 mm and the pitch L2 in the horizontal direction can be 185 mm.
  • the gates 20A to 20D are the outermost gates 20A to 20D, which are closest to each vertex 10A to LOD.
  • the distance LA1 between the lateral side 12A closest to the outermost gate 20A and the outermost gate 20A is 120% to 10%, preferably 100% to 20% of the pitch L1.
  • the distance LB1 between the vertical side 11A closest to the outermost gate 20A and the outermost gate 20A is 120% to 10%, preferably 100% to 20% of the pitch L2.
  • the distance LA2 between the lateral side 12B and the outermost gate 20B where the outermost gate 20B force is closest is 120% to 10% of the pitch L1, and preferably 100 % To 20%.
  • the distance LB2 between the vertical side 11A closest to the outermost gate 20B and the outermost gate 20B is 120% to 10%, preferably 100% to 20% of the pitch L2.
  • the distance LA3 between the lateral side 12A and the outermost gate 20C where the outermost gate 20C force is closest is 120% to 10%, preferably 100% to 20% of the pitch L1. %. Further, the distance LB3 between the vertical side 11B and the outermost gate 20C closest to the outermost gate 20C force is 120% to 10%, preferably 100% to 20% of the pitch L2.
  • the distance LA4 between the lateral side 12B and the outermost gate 20D where the outermost gate 20D force is closest is 120% to 10% of the pitch L1, preferably 100. % To 20%.
  • the distance LB4 between the vertical side 1 IB closest to the outermost gate 20D force and the outermost gate 20D is 120% to 10%, preferably 100% to 20% of the pitch L2.
  • the pitch L1 can be an average value of the intervals.
  • the pitch L2 can be an average value of each interval.
  • the distances LA1 to LA4 are preferably substantially equal to each other.
  • the distances LB1 to LB4 are preferably substantially equal to each other.
  • “substantially equal” means that the distances LA1 to LA4 have an error of 10% or less with respect to the average distance obtained by averaging the distances LA1 to LA4.
  • the error is preferably 5% or less, more preferably 1% or less.
  • the number of installed gates N is determined when the depth of the cavity is t (mm) and the area of the cavity is S (mm 2 ). It is preferable that the following mathematical formula (1) is satisfied.
  • the number of gates is less than the preferred range, there is a risk that unevenness in the thickness of the flat plate molded product will occur due to an increase in the flow distance of the resin within the cavity. Further, when the number of gates is larger than the preferable range, it may be difficult to manufacture a mold. For this reason, by setting the number of gates within the preferred range, it is possible to easily form a high-quality flat plate molded product.
  • the plurality of gates 20 are arranged on the intersection P of the lattice, as shown in FIG. 1, the plurality of gates 20 are connected to the vertical gate row 21 which is a vertical gate row.
  • horizontal gate row 22 which is a horizontal gate row.
  • the number of vertical gate rows 21 is several, and the number of horizontal gate rows 22 is three (odd number).
  • the number of gates 20 constituting the vertical gate row 21 is three, and the number of gates 20 constituting the horizontal gate row 22 is four.
  • the resin that is a constituent material of the flat plate molded product will be described.
  • the coconut resin include alicyclic resin having an alicyclic structure, a copolymer of an aromatic vinyl monomer and an alkyl ester (meth) acrylate ester, methallyl rosin, polycarbonate, polystyrene, acrylonitrile. -Styrene copolymer resin, ABS resin, and polyether sulfone.
  • a resin having an alicyclic structure, a methacrylic resin, and a copolymer of an aromatic butyl monomer and a (meth) acrylic acid alkyl ester monomer can be suitably used.
  • a resin having a cyclic structure can be particularly preferably used.
  • the resin having an alicyclic structure Since the resin having an alicyclic structure has good fluidity of the molten resin, it can be filled with mold cavity at a low injection pressure, and has extremely low hygroscopicity, so it has excellent dimensional stability. Since the specific gravity that does not cause warpage in the flat plate molded product is small, the flat plate molded product can be reduced in weight. In addition, rosin having an alicyclic structure has an advantage that weld lines are less likely to occur.
  • a resin having an alicyclic structure is a resin having an alicyclic structure in a main chain or a side chain.
  • rosin having an alicyclic structure in the main chain is particularly suitable because it has good mechanical strength and heat resistance.
  • the alicyclic structure is preferably a saturated cyclic hydrocarbon structure, and its carbon number is preferably 4 to 30, more preferably 5 to 20, and more preferably 5 to 15. More preferably.
  • the proportion of the repeating unit having an alicyclic structure in the alicyclic resin having an alicyclic structure is preferably 50% by weight or more, more preferably 70% by weight or more, and more preferably 90% by weight or more. More preferably.
  • rosins having an alicyclic structure include, for example, ring-opening polymers or ring-opening copolymers of norbornene monomers or hydrogenated products thereof, addition polymers or additions of norbornene monomers.
  • Copolymer or hydrogenated product thereof polymer of monocyclic cyclic olefin monomer or hydrogenated product thereof, polymer of cyclic conjugation monomer or hydrogenated product thereof, vinyl alicyclic carbonization Polymer or copolymer of hydrogen monomer or hydrogen additive thereof, polymer of vinyl aromatic hydrocarbon monomer or hydrogenated product of unsaturated bond part containing aromatic ring of copolymer And so on.
  • hydrogenated products of norbornene-based monomer polymers and hydrogenated products of unsaturated bonds including aromatic rings of vinyl aromatic hydrocarbon-based monomer polymers have mechanical strength and strength. Since it is excellent in heat resistance, it can be used particularly suitably.
  • the methacrylic resin is suitable for an optical member because it is excellent in transparency, tough and hardly cracks. Examples of the methacrylic resin include a methacrylic resin molding material containing 80% or more of a methyl methacrylate polymer defined in Japanese Industrial Standard JIS K 6717.
  • methacrylic resins stipulated in this standard methacrylic resin with a Vicat soft spot temperature of 96-100 ° C and a melt rate of 8 to 16 with a specified classification code of 100-120 has moderate fluidity and strength. Therefore, it can be suitably used.
  • the aromatic bulle monomer constituting the copolymer of the aromatic vinyl monomer and the (meth) acrylic acid alkyl ester is an aromatic vinyl monomer and a derivative thereof, such as styrene. , A-methylstyrene, m-methylstyrene, p-methylstyrene, 0-chlorostyrene, and P-chlorostyrene.
  • the (meth) acrylic acid alkyl ester include (meth) acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms.
  • (meth) acrylic acid alkyl ester methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate can be suitably used.
  • a copolymer of an aromatic butyl monomer and a (meth) acrylic acid alkyl ester is a copolymer of 20 to 60% by weight of an aromatic butyl monomer and 40 to 80% by weight of a (meth) acrylic acid alkyl ester. It is preferably a coalescence.
  • (meth) acrylic acid means metatalic acid and acrylic acid
  • (meth) acrylic means methacryl and acrylic.
  • thermoplastic elastomer examples include polybutadiene, a styrene-butadiene block copolymer and a hydrogenated carotenate thereof, and a styrene-isoprene block copolymer and a hydrogenated product thereof.
  • additives include light diffusing agents, antioxidants, ultraviolet absorbers, light stabilizers, colorants such as dyes and pigments, lubricants, plasticizers, antistatic agents, and fluorescent whitening agents. it can.
  • the light diffusing agent examples include a polystyrene polymer, a polysiloxane polymer, or fine particles made of a crosslinked product thereof, (meth) acrylic resin, fluorine resin, barium sulfate, calcium carbonate, silica, and talc. Can be mentioned.
  • a polystyrene polymer a polysiloxane polymer, or fine particles made of a crosslinked product thereof, (meth) acrylic resin, fluorine resin, barium sulfate, calcium carbonate, silica, and talc.
  • acrylic resin fluorine resin
  • barium sulfate calcium carbonate
  • silica silica
  • talc talc
  • the fine particles are particularly suitable because they have good dispersibility, excellent heat resistance, and no yellowing during molding.
  • the blending amount of the thermoplastic elastomer is usually 0.01 wt% to 50 wt%, preferably 0.05 wt% to 30 wt%.
  • the compounding quantity of the said additive is 0.01 to 30 weight% normally, Preferably it is 0.05 to 20 weight%.
  • the particle size of the light diffusing agent is usually 0.5 / z m to: LOO / z m in terms of average particle size, and preferably 0.5 m to 80 m.
  • FIG. 3 is a plan view of a cavity surface for explaining a method of manufacturing a light diffusing plate.
  • FIG. 4 is a flowchart for explaining the procedure of the method of manufacturing the light diffusing plate.
  • the horizontal gate row 22 includes three horizontal gate rows 22A, 22B, and 22C. Of these horizontal gate rows 22A, 22B, and 22C, the row that includes the gates 20S and 20T that are closest to the intersection of the diagonal lines of the cavity surface 10 is defined as the first horizontal gate row X, and this first horizontal gate row. Two gate rows close to the row are designated as the second horizontal gate row Y.
  • the lateral gate row 22B is the first lateral gate row X
  • the lateral gate row 22A and the lateral gate row 22C that are substantially the same distance from the first lateral gate row X are Second horizontal gate row Y.
  • the mold for injection molding is clamped at a predetermined pressure using a saddle mold clamping device (not shown) (step Sl).
  • the gate of the first horizontal gate row X is opened, and the resin is injected from the gate of the first horizontal gate row X at a constant injection rate (step S2: first step).
  • the resin injected into the cavity also flows out with a force corresponding to the first gate row X directed toward the outer peripheral side of the cavity surface 10.
  • the injection amount of the resin can be grasped by the injection time since the injection rate (injection speed) is constant.
  • step S3 it is determined whether or not the force with which the injection amount from the gates of the first horizontal gate row X becomes a predetermined amount. Specifically, this determination may be performed based on, for example, the injection time. If necessary, the resin injected from the gates of the first gate row X is changed into the first horizontal gate row X and the second horizontal gate. This may be done by checking whether or not the current has flown to about half the distance of row Y.
  • step S2 is repeated. Oil injection When the amount reaches the planned amount, the gate of the first horizontal gate row X is opened while the gate of the first horizontal gate row X is opened, and the gate of the first horizontal gate row X and the second horizontal gate row are opened. The resin is injected from the Y gate at the injection rate (step S4: second step).
  • step S5 it is determined whether or not the injection amounts from the gates of the first lateral gate row X and the gates of the second lateral gate row Y have become predetermined amounts as described above (step S5). If the injection amount of the resin does not reach the expected amount, repeat step S4. When the resin injection amount reaches the predetermined amount, the gates of the first horizontal gate row X and the second horizontal gate row Y are closed, and the injection from the gates of these gate rows X and Y is stopped. (Step S6). Thereafter, the injection mold is cooled (step S7), and the mold force is taken out of the light diffusion plate (step S8). As described above, one cycle of manufacturing the light diffusion plate is completed.
  • step S6 the timing of closing the gate is usually performed when the injection amount of the resin reaches a predetermined amount. For example, the state of filling the surface of the molded product is observed, and this is done. It may be performed when the state of filling becomes better.
  • the light diffusing plate is manufactured by repeating such a cycle a plurality of times.
  • the first gate column including the center side gate thereof is used, and the second gate column is arranged in the order closer to the first gate column. Since the injection timing of the resin is shifted in the order of the rows, even if the multiple gates are arranged at the intersections of the grid, there is no air pool in the cavity, and there is no burning in the air pool. It is possible to prevent the appearance defect from occurring. For this reason, high quality flat plate molded products can be manufactured.
  • the plurality of gates are arranged substantially evenly in this way, it is possible to keep the mold internal pressure within the cavity where the pressure does not partially rise low. Therefore, it is possible to more efficiently manufacture a high-quality flat plate molded product while keeping the in-mold pressure low.
  • the following effects can be obtained. Since the gate 20 is arranged on the cavity surface 10 so that the distance between the adjacent gates 20 is substantially constant, the mold internal pressure is approximately the same at any position within the cavity. For this reason, since the pressure inside the mold can be kept low, a mold clamping device having a small mold clamping force can be used, and space saving can be achieved.
  • the first lateral gate X and the second lateral gate row Y are divided into the center side of the cavity surface 10. After injecting the grease from the gate 20 of the lateral gate row X, the injection timing was shifted so that the gate 20 force of the lateral gate row Y outside also injects the grease. However, there is no air pocket in the cavity. For this reason, appearance defects such as burning caused by air accumulation do not occur in the obtained flat plate molded product, so that a high-quality light diffusion plate can be efficiently produced.
  • the present invention is not limited to the above-described embodiment!
  • the number of vertical gate rows X the number of horizontal gate rows is 4 X 3.
  • the gate rows The number of is not limited to the above number.
  • the size of the cavity surface is not limited to the above size.
  • the obtained flat plate molded article was used as the light diffusing plate, it may be used as optical members, such as a light-guide plate, and may be used as members other than an optical use.
  • the injection timing is adjusted based on the horizontal gate row 22. If the number of the vertical gate rows 21 is an odd number, the injection timing is adjusted based on the vertical gate rows 21. May be. Also, the gate row for timing adjustment can be a gate row along the long side, which is the long side, and the gate row along the vertical direction, which is the short side! / ,.
  • the distances LB1 to LB4 in the horizontal direction are preferably about 30% to 70% of the distance L2 in the horizontal direction (for example, the average distance).
  • the length is 45% to 55%. More preferably, it is 49% to 51%.
  • the vertical distances LA1 to LA4 are preferably about 30% to 70% of the vertical distance L1, and more preferably 45% to 55%. More preferably, it is 49% to 51%. According to such a configuration, it is possible to form a high-quality flat plate molded product in which uneven thickness and poor appearance are further improved by allowing the molten resin to flow more suitably.
  • the second embodiment has the first implementation described above in terms of the arrangement and number of gates provided in the injection mold, the timing of opening and closing the gate when manufacturing a flat molded product, and the like. This is different from the method for producing the injection mold according to the embodiment and the flat resin molded product made of resin, but otherwise the same injection mold as used in the first embodiment. Is used to manufacture a flat molded product. Therefore, in the following, detailed description of the parts common to the first embodiment will be omitted, and only different parts will be described in detail. Further, the same components as those in the first embodiment will be described using the same reference numerals.
  • the injection mold used in the second embodiment includes a fixed mold plate and a movable mold plate, as in the first embodiment described above, and includes a fixed mold plate and a movable mold plate.
  • a cavity is formed by the gap, and the depth of the cavity substantially matches the thickness of the obtained flat plate molded product.
  • FIG. 5 is a plan view schematically showing the cavity surface formed on the fixed mold plate, and corresponds to FIG. 1 in the first embodiment.
  • the cavity surface 10 is formed in a substantially rectangular shape, and the diagonal length is preferably 400 mm or more, more preferably 650 mm or more.
  • the vertical length and the horizontal length of the cavity surface 10 are not particularly limited, and are usually formed so that the horizontal length is larger than the vertical length. And the length in the horizontal direction may substantially coincide with each other.
  • FIG. 6 is a schematic diagram for explaining the position of the gate 20 on the cavity surface 10, and corresponds to FIG. 2 in the first embodiment.
  • a plurality of gates 20 communicating with the cavity surface 10 are formed on the fixed template, and each of the gates 20 has a longitudinal pitch L1 and a lateral pitch of the cavity surface 10.
  • L2 is formed at substantially equal intervals along the vertical direction and the horizontal direction.
  • the gates closest to each vertex 10A-: L0D are the outermost gates 20A-20D, respectively, and the distance LA1 between each outermost gate 20A-20D and the lateral side with respect to each of them is LA1.
  • ⁇ LA4 is 120% to 10% of L1, preferably 100% to 20%.
  • each outermost gate 20A to 20D, the distance LB1 ⁇ LB4 ⁇ the longitudinal sides for each or a 120-10 0/0 of L2, preferably I or 100 0 / 0-20 0/0 is there.
  • the plurality of gates 20 are arranged on the intersections of the lattices, as shown in FIG. 7, the plurality of gates 20 are arranged in the vertical direction as a vertical gate row.
  • Gate column They can be classified into (11th to 14th gate rows) and horizontal gate rows (21st to 24th gate rows), which are lateral gate rows.
  • the number of vertical gate rows is four (even numbers), and the number of horizontal gate rows is even (even numbers).
  • the number of gates 20 constituting the vertical gate row is four, and the number of gates 20 constituting the horizontal gate row is four.
  • the resin that is a constituent material of the flat molded product uses the same resin as that used in the first embodiment, even in the second embodiment. Therefore, detailed description is omitted.
  • FIG. 8 is a flowchart for explaining the procedure of the method of manufacturing the light diffusing plate.
  • the two gate rows closest to the intersection of the diagonal lines of the cavity surface are the 11th gate row and the 12th gate row, and this 11th gate row.
  • the two gate rows close to the twelfth gate row are the 13th gate row and the 14th gate row, respectively.
  • the two gates closest to the intersection of the diagonals of the cavity surface The gates are the 21st gate row and the 22nd gate row, and the two gate rows close to the 21st gate row and the 22nd gate row are the 23rd gate row and the 24th gate row, respectively. 1 gate row, 2nd gate row).
  • the mold for injection molding is clamped at a predetermined pressure using a mold clamping device (not shown) (step S11).
  • open each gate of the first group that is, (13, 21), (11, 22), (12, 21), (14, 22) gates, and make certain projections from these gates.
  • the resin is injected at a rate (step S12: first step).
  • step S12 first step.
  • the grease injected into the cavity flows out from each gate of the first group to the outer peripheral side of the cavity surface 10 as shown in FIG.
  • the injection amount of the resin can be grasped by the injection time since the injection rate (injection speed) is constant.
  • step S13 it is determined whether or not the injection amount from each gate of the first group has become a predetermined amount. Specifically, this determination may be performed based on, for example, the injection time. 1S If necessary, the resin injected from each gate of the first group is half the distance to the gate of the second group described later. You can do it depending on whether it has flowed to a certain level. Grease If the output amount has not reached the planned amount, the process of step S12 is continued. When the injection amount of the resin reaches the planned amount, each gate of the second group, that is, (13, 22), (11, 21), (12, 22), with the gates of the first group open.
  • FIG. 10 is a view showing a state in which the resin is injected from each gate of the first group and the second group.
  • the circles indicating the range of the grease flowing out from each gate of the first group overlap each other, and the circles indicating the range of the grease flowing out from each gate of the first group are the cavity surface.
  • the fat flows in the direction of the arrow shown in the figure so as to compensate for the slow part of the fat flow.
  • the resin is filled in the lateral direction of the cavity.
  • step S15 it is determined whether or not the injection amount from each gate of the second group has become a predetermined amount. If the injection amount of the resin does not reach the expected amount, continue the process of step S14. When the injection amount of the resin reaches a predetermined amount, each gate of the third group, that is, each of the 23rd gate row and the 24th gate row is left with the gates of the first group and the second group being opened. Gate ((13, 23), (11, 23), (12, 23), (14, 23), (13, 24), (11, 24), (12, 24), (14, 24) Each gate) is opened, and the resin is injected at the injection rate from the gates of the first group to the third group (step S16: third step).
  • step S17 it is determined whether or not the injection amount force from each gate of the third group has become a predetermined amount. If the injection amount of the resin does not reach the expected amount, continue the process of step S16. When the injection amount of the resin reaches the predetermined amount, the gates of the first group to the third group are closed, and the injection from these gates is stopped (step S18). Thereafter, the injection mold is cooled (step S19), and the mold force light diffusion plate is taken out (step S20). As described above, one cycle of manufacturing the light diffusion plate is completed.
  • step S18 the timing for closing the gate is normally performed when the amount of the resin spray reaches a predetermined amount. Observation may be made when this filling state becomes good.
  • the light diffusing plate is manufactured by repeating such a cycle a plurality of times.
  • the number of vertical gate rows ⁇ the number of horizontal gate rows is 4 ⁇ 4. If the number of vertical and horizontal gate rows is an even number, the number of gate rows The number is not limited to the number.
  • FIG. 12 is a diagram for explaining the timing of opening the gate when the number of vertical gate rows X the number of horizontal gate rows is 6 x 8.
  • the resin is injected from each gate included in the first group in the first process, and the resin is injected from each gate included in the first group and the second group in the second process.
  • the resin is injected from each gate included in the second group, and in the second step, the resin is injected from each gate included in the first group and the second group.
  • the gates included in the horizontal gate rows closest to the first group and the second group are opened to inject the resin, and further, the gates included in the outer horizontal gate rows are opened to open the resin. Inject.
  • the third embodiment which is another manufacturing method for manufacturing a light diffusing plate, which is a flat resin molded product made of resin, using the injection mold according to the second embodiment described above.
  • the processing procedure is the same as the procedure in the second embodiment shown in FIG. 8, and will be described with reference to FIG.
  • step S 11 the mold for injection molding is clamped at a predetermined pressure using a mold clamping device (not shown) (step S 11).
  • each gate of the first group that is, each gate of (11, 22) and (12, 21) shown in FIG. 13 is opened, and a constant injection rate is obtained from these gates.
  • step S12 the resin is injected.
  • the resin injected into the cavity flows out from the gates of the first group toward the outer peripheral side of the cavity surface 10.
  • the range of the spread of the resin injected from each gate of the first group is indicated by a solid circle. The injection amount of the resin can be grasped by the injection time since the injection rate (injection speed) is constant.
  • step S13 it is determined whether or not the injection amount from each gate of the first group has become a predetermined amount. Specifically, for example, this determination may be performed based on the injection time. If necessary, the resin injected from each gate of the first group flows to a position about half the distance from the adjacent gate. It may be done depending on whether or not it is correct. If the injection amount of the resin does not reach the expected amount, continue the process of step S12. The injection amount of sallow reaches the planned amount In this case, as shown in FIG. 13, with the gates of the first group open, the gates of the second group, ie, (11, 21), (12, 22) shown in FIG.
  • step S14 second step.
  • the range of spread of the resin injected from each gate of the second group is indicated by a dotted circle.
  • step S15 it is determined whether or not the injection amount force from each gate of the second group is equal to the predetermined amount. If the resin injection amount has not reached the expected amount, continue with step S14. When the injection amount of the resin reaches the predetermined amount, the gates of the third group, that is, the gates of the thirteenth group as shown in FIG.
  • Each gate of the row, the 14th gate row, the 23rd gate row and the 24th gate row ((13, 23), (13, 21), (13, 22), (13, 24), (14, 23), (14, 21), (14, 22), (14, 24), (11, 23), (12, 23), (11, 24), (12, 24) gates))
  • the resin is injected from the gates of the first group to the third group at the injection rate (step S16: third step).
  • step S17 it is determined whether or not the injection amount from each gate of the third group has become a predetermined amount. If the injection amount of the resin does not reach the expected amount, continue the process of step S16. When the injection amount of the resin reaches the predetermined amount, the gates of the first group to the third group are closed, and the injection from these gates is stopped (step S18). Thereafter, the injection mold is cooled (step S19), and the mold force light diffusion plate is taken out (step S20). As described above, one cycle of manufacturing the light diffusion plate is completed.
  • step S18 the timing for closing the gate is normally performed when the amount of the resin spray reaches a predetermined amount. Observation may be made when this filling state becomes good.
  • the light diffusing plate is manufactured by repeating such a cycle a plurality of times.
  • the number of vertical gate rows x the number of horizontal gate rows is 4 x 4.
  • the number of gate rows is not limited to the number. In that case, after controlling the injection timing of 4 x 4 gates by the above-mentioned method, the outer gates of the cavity are opened sequentially and the resin is injected. That is, The gates are opened sequentially from the inside to the outside.
  • the resin is injected from each gate included in the first group or each gate included in the second group, and the second step
  • resin is injected from each gate included in the second group or each gate included in the first group, and as a third step, the resin is injected from each gate of the 23rd gate row and the 24th gate row.
  • the injection timing of the resin from each gate is shifted, or as the first step, the resin is injected from each gate included in the first group or each gate included in the second group, As the second step, the resin is injected from each gate included in the second group or from each gate included in the first group, and as the third step, the thirteenth gate row, the fourteenth gate row, the twenty-third gate row and the second gate row Injecting grease from each gate in the 24 gate row.
  • the injection timing of the resin from each gate is shifted, so even if a plurality of gates are arranged at the intersections of the lattice, there is no air pool in the cavity, and It is possible to prevent appearance defects such as burning. For this reason, a high quality flat plate molded product can be manufactured.
  • the plurality of gates are arranged substantially evenly in this way, it is possible to keep the mold internal pressure within the cavity that prevents the pressure from partially rising. Accordingly, it is possible to manufacture a high-quality flat plate product more efficiently while keeping the in-mold pressure low.
  • the gate 20 is arranged on the cavity surface 10 so that the distance between the adjacent gates 20 is substantially constant, the mold internal pressure is approximately the same at any position within the cavity. For this reason, since the mold internal pressure can be kept low, a mold clamping device with a small mold clamping force can be used, and space saving can be achieved. Also, the gates were divided into the first group to the third group, and the injection timing was shifted so that the grease was emitted from each gate 20 in the order of the first group, the second group, and the third group. Therefore, even if the gates 20 are arranged substantially evenly, there is no air pool in the cavity. For this reason, the obtained flat plate molded product does not suffer from appearance defects such as burning caused by air accumulation, so that a high-quality light diffusion plate can be efficiently manufactured.
  • the resin is injected from each gate included in the first group in the first step, and included in the second group in the second step.
  • the grease is injected from each gate, but in the first process, the resin is injected from each gate included in the second group, and in the second process, the resin is injected from each gate included in the first group. You may make it do.
  • the size of the cavity surface is not limited to the above size.
  • the obtained flat plate molded product is a light diffusion plate, but may be an optical member such as a light guide plate, or may be a member other than an optical application.
  • each of the horizontal distances LB1 to LB4 is approximately 30% to 70% of the horizontal distance L2 (for example, the average distance). It is more preferable that the length is 45% to 55%, and it is more preferable that the length is 49% to 51%.
  • the vertical distances LA1 to LA4 are preferably about 30% to 70% of the vertical distance L1, and more preferably 45% to 55%. More preferably, it is 49% to 51%. According to such a configuration, a high quality flat plate molded product with improved thickness unevenness and appearance defect can be formed by flowing the molten resin more suitably.
  • FIG. 14 is a diagram illustrating a configuration of the liquid crystal display device.
  • the liquid crystal display device 30 includes a pair of liquid crystal substrates 31 disposed opposite to each other, a liquid crystal panel including a liquid crystal layer 32 sandwiched between the pair of liquid crystal substrates 31, and a pair of polarizing plates disposed so as to sandwich the liquid crystal panel.
  • a light plate 33, a direct type backlight 34 that illuminates the LCD panel with a back force, and a liquid crystal panel and a direct type backlight 34 are arranged between the liquid crystal panel and the direct type backlight 34 to make light uniform, diffuse light, or collect light.
  • An optical film 35 having a function of illuminating and a light diffusion plate 36 manufactured by the manufacturing method according to each of the above-described embodiments are provided.
  • the direct type backlight 34 is provided with a plurality of lamps 37 and a reflector 38 that are also cold cathode fluorescent lamps and the like.
  • the liquid crystal display device since the light diffusion plate 36 manufactured by the manufacturing method according to the above-described embodiment is provided, the liquid crystal panel can be well illuminated. I'll do it.
  • a light diffusion plate was molded by an injection molding machine (screw diameter ⁇ 90 mm, maximum mold clamping 850 t).
  • the mold has a substantially rectangular cavity surface on the main surface of the fixed mold plate.
  • the dimensions of the cavity surface were 430 mm long, 740 mm wide, and 856 mm diagonal.
  • the cavity depth was 2.0 mm.
  • the cavity surface of the fixed mold is provided with twelve hot runner type valve gates having a diameter of 2mm in communication with the cavity surface.
  • the gate gap L2 in the horizontal direction was 185mm
  • the gate gap L1 in the vertical direction was 143.3mm.
  • the spacing error in each direction was 0%.
  • the distance LA1 between the outermost gate 20A and the vertical side 11A of the cavity surface shown in FIG. 1 is 71.7 mm
  • the distance LB1 between the outermost gate 20A and the lateral side 12A of the cavity surface is LB1. It was 92.5 mm.
  • the distance 1 ⁇ ⁇ 2 was 71.7 mm and the distance LB2 was 92.5 mm.
  • the distance L A3 was 71.7 mm, and the distance LB3 was 92.5 mm.
  • the distance LA4 was 71.7 mm and the distance LB4 was 9 2.5 mm. Therefore, the distance error was 0%.
  • Each distance LA1 to LA4 was 50% of the distance L1, and each distance LB1 to LB4 was 50% of the distance L2.
  • the injection molding conditions were a cylinder temperature of 275 ° C, a hot runner temperature of 275 ° C, a mold temperature of 78 ° C, an injection speed of lOOmmZ seconds, and a cooling time of 30 seconds.
  • valve gates of the first lateral gate row were opened, and the resin was injected from the valve gates of the first lateral gate row. Subsequently, 1.5 seconds after resin injection from the valve gate of the first horizontal gate row, the second gate gate open the valve gate, and the first and second horizontal gate row gate gates and The resin was injected from the valve gate. Next, when the resin injection amount reached the predetermined amount and it was determined that the resin filling state near the cavity surface was sufficient without sink marks, all valve gates were closed and injection stopped. . At this time, the pressure inside the mold at the time of injection was 180 kgfZcm 2 (18 MPa). Then gold on the above conditions After cooling the mold, the light diffusing plate was taken out of the mold to obtain a light diffusing plate.
  • the obtained light diffusing plate was a non-defective product having no appearance defect caused by air accumulation.
  • the variation in thickness was measured by a micrometer (manufactured by Mitutoyo Corporation) and found to be 60 m.
  • the dimensions of the cavity surface were changed as follows, and 2.5 seconds after opening the valve gate of the first horizontal gate row, the same as in Example 1 except that the valve gate of the second gate row was opened. A light diffusing plate was obtained.
  • the dimensions of the cavity surface were 600 mm long, 1,020 mm wide, and a diagonal length of 1,183 mm.
  • the horizontal gate interval L2 was 233 mm
  • the vertical gate interval L 1 was 181.7 mm.
  • the spacing error in each direction was 0%.
  • the distance LA1 between the outermost gate 20A and the longitudinal side 11A of the cavity surface is 1 18.3 mm
  • the distance LB 1 between the outermost gate 20A and the lateral side 12A of the cavity surface is 160.5 mm. .
  • the distance LA2 was 118.3 mm and the distance LB2 was 160.5 mm.
  • the distance LA3 was 118.3 mm, and the distance LB3 was 160.5 mm.
  • the distance LA4 was 118.3mm and the distance LB4 was 160.5mm. Therefore, the distance error was 0%.
  • Each distance LA1 to LA4 was 65.1% of the distance L1, and each distance LB1 to LB4 was 68.9% of the distance L2.
  • the depth of the cavity was 2.0 mm.
  • the mold internal pressure at the time of injection was 190kgfZcm 2 (19MPa).
  • the obtained light diffusing plate was a good product with no appearance defect caused by air accumulation. Furthermore, the thickness variation of the light diffusing plate was 100 m.
  • a light diffusion plate was obtained in the same manner as in Example 1 except that all the valve gates were opened at the same time and the resin was injected at the same time.
  • the obtained light diffusing plate had a poor appearance due to burning caused by air accumulation. Furthermore, the variation in the thickness of the light diffusing plate was 200 m.
  • Example 1 As shown in Fig. 15, except that the number of valve gates is 8 (2 in the vertical direction and 4 in the horizontal direction) and all the valve gates are opened at the same time and the grease is injected at the same time.
  • Example 1 Similarly, a light diffusion plate was obtained.
  • the dimensions of the mold cavity surface were 430 mm long, 740 mm wide, and 856 mm diagonal. The depth of the cavity was 2.0mm.
  • the lateral gate spacing (L2 in Fig. 2) was 185mm
  • the vertical gate spacing (L1 in Fig. 2) was 215mm.
  • the gap error in the horizontal direction was 0%
  • the distances (LB1 to LB4 in Fig. 2) were 160.5 mm each, and the distances (LA1 to LA4 in Fig. 2) were each 118.3 mm.
  • the distance error in each direction was 0%.
  • Each distance (LA1 to LA4 in Fig. 2) is 50% of the distance (L1 in Fig. 2), and each distance (LB1 to LB4 in Fig. 2) is equal to the distance (L2 in Fig. 2). It was 50% long.
  • the pressure inside the mold at the time of injection was 200kgfZcm 2 (20MPa). Further, the obtained light diffusing plate had a poor appearance due to burning caused by air pockets. Furthermore, the thickness variation of the light diffusing plate was 200 ⁇ m.
  • the interval between the horizontal gate rows is narrowed, and the dimensions of the cavity surface are changed as follows.
  • a light diffusing plate was obtained in the same manner as in Comparative Example 1.
  • the dimensions of the mold cavity surface were 600 mm long, 1,02 Omm wide, and 1,183 mm diagonal.
  • the lateral gate spacing (L2 in Fig. 2) was 255mm and the vertical gate spacing (L1 in Fig. 2) was 50mm.
  • the spacing error in each direction was 0%.
  • the distances (LB1 to LB4 in Fig. 2) were 125.5 mm each, and the distances (LA1 to LA4 in Fig. 2) were 112.5 mm each.
  • the distance error in each direction was 0%.
  • Each distance (LA1 to LA4 in FIG. 2) was 225% of the distance (L1 in FIG. 2).
  • Each distance (LB1 to LB4 in FIG. 2) was 50% of the distance (L2 in FIG. 2).
  • the depth of the cavity was 2.0 mm.
  • the lateral gate spacing was 230 mm, and the longitudinal gate spacing was 50 mm. In each direction, the spacing error was 0%.
  • the in-mold pressure at the time of injection was 250 kgfZcm 2 (25 MPa). Moreover, it was a good product without any appearance defects that could occur due to air accumulation.
  • the thickness variation of the light diffusing plate was 200 m.
  • the in-mold pressure could be kept low, and the obtained light diffusion plate had no appearance defects due to gas burning or the like, and suppressed thickness unevenness.
  • Comparative Examples 1 and 2 the obtained light diffusion plate had poor appearance and uneven thickness due to gas burn.
  • the mold pressure could not be kept low, and the obtained light diffusion plate had uneven thickness.
  • a light diffusion plate was formed by an injection molding machine (screw diameter ⁇ 90 mm, maximum clamping force 85 Ot).
  • the mold has a substantially rectangular cavity surface on the main surface of the fixed mold plate.
  • the dimensions of the cavity surface were 430 mm long, 740 mm wide, and a diagonal length of 856 mm.
  • the cavity depth was 2.0 mm.
  • the cavity surface of the fixed mold plate is provided with 16 hot runner type valve gates having a diameter of 2 mm, which communicate with the cavity surface.
  • the gate gap L2 in the horizontal direction was 185mm
  • the gate gap L1 in the vertical direction was 107.5mm.
  • the spacing error in each direction was 0%.
  • the distance LA1 between the outermost gate 20A and the longitudinal side 11A of the cavity surface shown in FIG. 5 is 92.5 mm
  • the distance LB1 between the outermost gate 20A and the lateral side 12A of the cavity surface is 53. It was 8 mm.
  • the distance LA2 was 92.5 mm and the distance LB2 was 53.8 mm.
  • the distance LA3 was 92.5 mm and the distance LB3 was 53.8 mm.
  • the distance LA4 was 92.5 mm, and the distance LB4 was 53.8 mm. Therefore, the distance error was 0%.
  • Each distance LA1 to LA4 was 50% of the distance L1, and each distance LB1 to LB4 was 50% the distance L2.
  • the injection molding conditions were a cylinder temperature of 275 ° C, a hot runner temperature of 275 ° C, a mold temperature of 78 ° C, an injection speed of lOOmmZ seconds, and a cooling time of 30 seconds.
  • the first group of valve gates was opened, and the resin was injected from the first group of valve gates.
  • grease spray from the valve gate of the first group 1.5 seconds after exit, the second group of valve gates was opened, and the resin was injected from the first group of valve gates and the second group of valve gates.
  • 1.5 seconds after the injection of the resin from the valve gate of the second group the valve gate of the third group was opened and the resin was injected from the first to third valve gates.
  • the injection amount of the resin reaches the planned amount and it is determined that the resin filling state near the cavity surface is sufficient without sink marks, all valve gates are closed and the injection is stopped. did.
  • the in-mold pressure at the time of injection was 180 kgfZcm 2 (18 MPa). Then, after cooling a metal mold
  • the obtained light diffusing plate was a non-defective product having no appearance defect caused by air accumulation.
  • the variation in thickness was measured by a micrometer (manufactured by Mitutoyo Corporation) and found to be 60 m.
  • the dimensions of the cavity surface were changed as follows, and the opening and closing of the valve gate was controlled in the same manner as in Example 1 to obtain a light diffusing plate.
  • the dimensions of the cavity surface were 600 mm long, 1,02 Omm wide, and 1,183 mm diagonal.
  • the horizontal gate interval L2 was 255 mm
  • the vertical gate interval L1 was 150 mm.
  • the spacing error in each direction was 0%.
  • the distance L A1 between the outermost gate 20A and the longitudinal side 11A of the cavity surface is 75 mm
  • the distance LB 1 between the outermost gate 20A and the lateral side 12A of the cavity surface is 127.5 mm.
  • the distance LA2 was 75 mm and the distance LB2 was 127.5 mm.
  • the distance LA3 was 75 mm and the distance LB3 was 127.5 mm.
  • the distance LA4 was 75mm and the distance LB4 was 127.5mm. Therefore, the distance error was 0%.
  • Each distance LA1 to LA4 was 50% of the distance L1, and each distance LB1 to LB4 was 50% of the distance L2.
  • the depth of the cavity was 2.0mm.
  • the mold internal pressure at the time of injection was 180kgfZcm 2 (18MPa).
  • the obtained light diffusing plate was a good product with no appearance defect caused by air accumulation. Furthermore, the thickness variation of the light diffuser was 80 ⁇ m.
  • Example except that all valve gates are opened at the same time and the grease is injected at the same time.
  • a light diffusing plate was obtained in the same manner as in 3.
  • the obtained light diffusing plate had a poor appearance due to burning caused by air accumulation.
  • the variation in the thickness of the light diffusing plate was 200 m.
  • the number of valve gates is 8 (2 in the vertical direction and 4 in the horizontal direction), and the vertical gate interval is narrower than the horizontal gate interval, and all the valve gates are used simultaneously.
  • a light diffusing plate was obtained in the same manner as in Example 2 except that the resin was simultaneously injected and the pressure inside the mold was 25 MPa. The obtained light diffusing plate had a poor appearance due to burning caused by air pockets. Furthermore, the variation in the thickness of the light diffusing plate is about 200 m.
  • the method for producing a flat molded product of the present invention is suitable for producing a flat molded product using a mold, such as a light diffusing plate, a light guide plate, a reflecting plate, etc. constituting a backlight device of a liquid crystal display. It can be applied to the production of optical components and other flat plate molded products.

Abstract

Dans le cadre de la présente invention, une pluralité de portes (20) sont agencées sur une surface de cavité sensiblement rectangulaire (10). Les portes (20) sont agencées le long de la direction longitudinale ou la direction latérale à des intervalles sensiblement égaux. Une pluralité de portes sont agencées par trois rangées latérales de portes (22) et quatre rangées longitudinales de portes. Une rangée latérale de portes (22B) au milieu des trois rangées latérales de portes peut être une première rangée latérale de portes (X), et les rangées latérales de portes (20A, 20C) à l'extérieur de la rangée latérale médiane de portes peuvent être des secondes rangées latérales de portes (Y). Une résine est projetée à partir de la première rangée latérale de portes (X), et lorsque la quantité de projection de la résine devient une quantité prescrite, la résine est projetée à partir des secondes rangées latérales de portes (Y) et une plaque plate moulée est fabriquée.
PCT/JP2007/052089 2006-02-13 2007-02-07 Procede de fabrication de plaque plate moulee, et plaque plate moulee WO2007094209A1 (fr)

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Publication number Priority date Publication date Assignee Title
CN106514964A (zh) * 2016-10-14 2017-03-22 深圳天珑无线科技有限公司 一种侧壁并排模内自动切水口结构
WO2017137172A1 (fr) * 2016-02-11 2017-08-17 Osram Gmbh Procédé de fabrication d'un module d'éclairage, module d'éclairage et utilisation d'un élément optique dans un module d'éclairage
JP2020192781A (ja) * 2019-05-30 2020-12-03 三光合成株式会社 射出成型装置及び射出成型方法

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Publication number Priority date Publication date Assignee Title
JPH07112448A (ja) * 1993-10-18 1995-05-02 Toyoda Gosei Co Ltd 樹脂成形品の射出成形方法及び成形用金型
JP2004117544A (ja) * 2002-09-24 2004-04-15 Nippon Zeon Co Ltd 光拡散板の製造方法
WO2005088358A1 (fr) * 2004-03-12 2005-09-22 Zeon Corporation Diffuseur de lumière et méthode pour sa fabrication
JP2005271306A (ja) * 2004-03-23 2005-10-06 Nippon Zeon Co Ltd 光拡散板の製造方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07112448A (ja) * 1993-10-18 1995-05-02 Toyoda Gosei Co Ltd 樹脂成形品の射出成形方法及び成形用金型
JP2004117544A (ja) * 2002-09-24 2004-04-15 Nippon Zeon Co Ltd 光拡散板の製造方法
WO2005088358A1 (fr) * 2004-03-12 2005-09-22 Zeon Corporation Diffuseur de lumière et méthode pour sa fabrication
JP2005271306A (ja) * 2004-03-23 2005-10-06 Nippon Zeon Co Ltd 光拡散板の製造方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017137172A1 (fr) * 2016-02-11 2017-08-17 Osram Gmbh Procédé de fabrication d'un module d'éclairage, module d'éclairage et utilisation d'un élément optique dans un module d'éclairage
CN106514964A (zh) * 2016-10-14 2017-03-22 深圳天珑无线科技有限公司 一种侧壁并排模内自动切水口结构
JP2020192781A (ja) * 2019-05-30 2020-12-03 三光合成株式会社 射出成型装置及び射出成型方法
JP7257256B2 (ja) 2019-05-30 2023-04-13 三光合成株式会社 射出成型装置及び射出成型方法

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