JP2001062874A - Molding method of thin-walled molded article having large area - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of molding a thin-walled plate-shaped (wedge-shaped), sheetlike or film-like molded article having a large area with the good transfer properties from a mold, concretely, a method for molding the thin-walled optical member having a large area and reduced in brightness irregularity of a liquid crystal display device. SOLUTION: A slit gate with a gate cross-sectional area S of 110 mm2 is provided to a mold (a ratio S/L of the cross-sectional area S of the gate and the max. flow length L of the molten resin in a cavity is about 0.4 mm2/mm and mold clamping force is 200 ton) for molding a wedge-shaped light guide plate on the side of the short side of the mold and this mold is filled with a compsn. consisting of an alicyclic olefin polymer and a hydrogenated styrene/ butadiene/styrene block copolymer and mold clamping force is subsequently raised to 450 ton to obtain the wedge-shaped light guide plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a large-area thin-walled molded product, and more particularly, to a method of molding a thin plate-shaped (wedge-shaped), sheet-shaped or film-shaped molded product over a large area. The present invention relates to a method capable of molding with good transferability from paper.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a backlight unit and a liquid crystal display. The backlight unit includes a light source such as a fluorescent lamp, and an optical member such as a light guide plate that guides light from the light source to the liquid crystal display unit, a light diffusion plate that controls the traveling direction of light, and a light collector. I have. It is required that the width of the screen of the liquid crystal display device be increased from the viewpoint of improving visibility. In order to configure a device having a large-area liquid crystal display screen, it is necessary to increase the area of a light guide plate, a light diffusion plate, and the like used in the backlight unit. The liquid crystal display device can be easily made thinner, unlike the CRT type. However, as the size of the screen of the liquid crystal display device increases, unevenness in brightness tends to occur in light from the backlight, and the mechanical strength also decreases. Therefore, it is necessary to increase the thickness of the light guide plate and the like used in the backlight unit, and the thinning effect, which is an inherent advantage of the liquid crystal display device, is reduced.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to form a thin plate-like (wedge-like), sheet-like or film-like molded product with a large area with good transferability from a mold. It is an object of the present invention to provide a method, more specifically, a method of forming an optical member for a liquid crystal display device having a large-area thin-walled shape and having less luminance unevenness. The present inventors have conducted intensive studies to achieve the above object, and as a result, the ratio S / L (mm ² / mm) of the cross-sectional area S of the gate to the maximum flow length L when the molten resin flows from the gate. ) By injection molding using a mold having a value of 0.1 or more, or to a mold clamped with a mold clamping force of 50 to 250 tons.
After filling the resin at 0 to 600 kgf / cm ² , the mold clamping force is increased to 300 to 500 tons, and molding is performed to form a thin plate (wedge), sheet, or film over a wide area. It has been found that a molded product can be molded with good transferability from a mold, and the present invention has been completed based on this finding.

[0004]

Thus, according to the present invention, the ratio S / L (mm ² / mm) of the cross-sectional area S of the gate to the maximum flow length L of the molten resin in the cavity is 0. .
A method for molding a large-area thin-walled product by injection molding using one or more molds, and an injection filling pressure of 50 to 600 kgf in a mold clamped with a mold clamping force of 50 to 250 tons.
/ Cm ² after filling the resin, the mold clamping force is 300 to 5
The present invention provides a method for forming a large-area thin-walled molded product which is raised to 00 tons and molded.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first molding method of the present invention, the ratio S / L (mm ² / mm) of the cross-sectional area S of the gate to the maximum flow length L of the molten resin in the cavity is 0. .1 or more,
Preferably, injection molding is performed using a mold of 0.2 or more. If the S / L (mm ² / mm) is less than 0.1, the mold transferability becomes insufficient, and in the case of a light guide plate, uneven brightness tends to occur due to poor transfer.

The mold used in the present invention has a gate having a sectional area S. The gate in the present invention is not particularly limited as long as it is for obtaining a thin-walled molded product, but a so-called slit gate (also sometimes referred to as a flat gate or a film gate) having an elongated shape is preferable.
The length t of the short side of the gate cross section is usually 5 to 100%, preferably 10 to 100% with respect to the thickness of the large-area thin-walled molded product.
%, Particularly preferably 20 to 100%, specifically 0.2 to 2.5 mm. The length w of the long side is usually 10 to 100% with respect to the length of the side of the large-area thin-walled molded product,
Preferably it is 20 to 80%. The gate land length is not particularly limited, but is usually 3 mm or less.

[0007] The gate is usually arranged at a portion corresponding to the side surface (thickness portion) of the large-area thin-walled molded product. In the present invention, it is preferable to provide, in a portion corresponding to the side surface of the large-area thin-walled molded product, a portion where the maximum flow length L of the molten resin in the cavity becomes shorter. Specifically, in the case of a rectangular large-area thin-walled molded product, it is provided at a portion corresponding to the central side surface of the long side. In a light guide plate that emits light from the side and emits light to the front, if a gate is placed in a portion corresponding to the light incident surface, gate marks may remain in the light incident portion (maximum thickness portion). After molding the light incident part,
Post-processing such as polishing is required. Therefore, in the case of the light guide plate, it is preferable to arrange a gate on the opposite side (minimum thickness portion) or the side portion of the light incident portion. In the case of a multi-cavity mold, it is preferable to arrange the gates so that the cavity arrangement is as symmetrical as possible with respect to the sprue.

[0008] The second molding method according to the present invention is characterized in that the molding method is 50 to 250
Injection pressure 50-600 kgf / c in a mold clamped with a clamping force of 60-230 tons, preferably 60-230 tons.
After filling the resin with m ² , preferably 100 to 400 kgf / cm ² , the mold is molded by increasing the mold clamping force to 300 to 500 tons, preferably 350 to 470 tons.

The adjustment of the mold clamping force is performed by a known mold clamping method. For example, there are a toggle type and a direct pressure type. Usually, when the mold clamping force is reduced, burrs are easily generated. In the present invention, both the mold clamping force at the time of filling the resin and the injection filling pressure are reduced, and the mold clamping force is increased after filling the resin. In the present invention, the holding pressure is usually 600 to 1100 kg.
f / cm ² , preferably 650 to 1050 kgf / cm
^{Make 2}

According to the molding method of the present invention, a large-area thin-walled molded product, that is, a large-area portion A (mm ² ) and a thin-walled portion thickness d [a wedge-shaped large-area thin-walled molded product have a small thickness. Average value] (mm) and the ratio (A / d) is 20,000
mm ² / mm or more, preferably 30,000 mm ² / mm
As described above, more preferably 40,000 mm ² / mm or more can be easily obtained without poor transfer. In addition,
In the case of a multi-cavity mold, it means the total value of the ratio (A / d) of the area A (mm ² ) of the large area part and the thickness d (mm) of the thin part of each molded product.

The temperature of the mold when the resin is filled in the mold ranges from 10 ° C. lower than the glass transition temperature of the resin to 40 ° C. higher than the glass transition temperature, preferably from the glass transition temperature to the glass transition temperature. It is preferable to set the temperature to a temperature higher by 20 ° C. than the transition temperature. Within this range, a large-area thin-walled molded product can be easily obtained without transfer failure.

The resin to which the molding method of the present invention can be applied has a glass transition temperature of usually 50 ° C. or higher, preferably 70 ° C.
Those having a temperature of not less than ° C are preferred. Also, its 280 ° C,
2. Melt flow rate at 16 kgf (JIS
K6719), but usually 20 to 100 g / 10 min.
Preferably it is 25 to 95 g / 10 minutes.

The resin which can be suitably applied to the molding method of the present invention is an alicyclic olefin polymer. The alicyclic olefin polymer is a polymer having an alicyclic structure in a main chain and / or a side chain. From the viewpoints of mechanical strength and heat resistance, a polymer containing an alicyclic structure in the main chain is preferable. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of mechanical strength, heat resistance, and the like. In addition, examples of the alicyclic structure include a monocyclic ring, a polycyclic ring, a condensed polycyclic ring, a bridged ring, and a polycyclic ring obtained by combining these. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30.
When the number is in the range of 5 to 20, more preferably 5 to 15, the mechanical strength, heat resistance, and various properties of the moldability are highly balanced and suitable. The alicyclic olefin polymer used in the present invention is usually a thermoplastic one.

The alicyclic olefin polymer usually contains a repeating unit derived from an olefin having an alicyclic structure (hereinafter sometimes referred to as an alicyclic olefin). The proportion of the repeating unit derived from the alicyclic olefin in the alicyclic olefin polymer is appropriately selected depending on the purpose of use,
It is usually from 30 to 100% by weight, preferably from 50 to 100% by weight, more preferably from 70 to 100% by weight. If the proportion of the repeating unit derived from an alicyclic olefin is too small, the heat resistance is poor, which is not preferable. The repeating unit other than the alicyclic olefin-derived repeating unit is not particularly limited, and is appropriately selected depending on the purpose of use.

Further, the alicyclic olefin polymer may have a polar group such as a hydroxyl group or a carboxyl group. Examples of the polar group include a hydroxyl group, a carboxyl group, an oxy group, an epoxy group, a glycidyl group, an oxycarbonyl group, a carbonyloxy group, a carbonyl group, an amino group, an ester group, and the like.

The alicyclic olefin polymer is usually obtained by addition polymerization or ring-opening polymerization of an alicyclic olefin and, if necessary, hydrogenation of an unsaturated bond portion or addition polymerization of an aromatic olefin. And hydrogenation of the aromatic ring portion of the polymer. Further, the alicyclic olefin polymer having a polar group is, for example, by introducing a compound having a polar group into the alicyclic olefin polymer by a modification reaction, or copolymerizing a monomer having a polar group. It is obtained by copolymerization as a component.

The alicyclic olefin used to obtain the alicyclic olefin polymer includes bicyclo [2.2.
1] -hept-2-ene (common name: norbornene), 5
-Methyl-bicyclo [2.2.1] -hept-2-ene, 5,5-dimethyl-bicyclo [2.2.1] -hept-2-ene, 5-ethyl-bicyclo [2.2.1] ]-
Hept-2-ene, 5-butyl-bicyclo [2.2.
1] -Hept-2-ene, 5-hexyl-bicyclo [2.2.1] -hept-2-ene, 5-octyl-bicyclo [2.2.1] -hept-2-ene, 5-octadecyl -Bicyclo [2.2.1] -hept-2-ene,
5-ethylidene-bicyclo [2.2.1] -hept-2
-Ene, 5-methylidene-bicyclo [2.2.1] -hept-2-ene, 5-vinyl-bicyclo [2.2.1]
-Hept-2-ene,

5-propenyl-bicyclo [2.2.1]
-Hept-2-ene, 5-methoxy-carbinyl-bicyclo [2.2.1] -hept-2-ene, 5-cyano-
Bicyclo [2.2.1] -hept-2-ene, 5-methyl-5-methoxycarbonyl-bicyclo [2.2.1]
-Hept-2-ene, 5-ethoxycarbonyl-bicyclo [2.2.1] -hept-2-ene, bicyclo [2.
2.1] -Hept-5-enyl-2-methylpropionate, bicyclo [2.2.1] -hept-5-enyl-
2-methyloctaneate,

Bicyclo [2.2.1] -hept-2-ene-5,6-dicarboxylic anhydride, 5-hydroxymethylbicyclo [2.2.1] -hept-2-ene, 5,6
-Di (hydroxymethyl) -bicyclo [2.2.1]-
Hept-2-ene, 5-hydroxy-i-propylbicyclo [2.2.1] -hept-2-ene, 5,6-dicarboxy-bicyclo [2.2.1] -hept-2-ene, Bicyclo [2.2.1] -hept-2-ene-5,
6-dicarboxylic imide, 5-cyclopentyl-bicyclo [2.2.1] -hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1] -hept-2-ene, 5
-Cyclohexenyl-bicyclo [2.2.1] -hept-2-ene, 5-phenyl-bicyclo [2.2.1]-
Hept-2-ene,

Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene), tricyclo [4.3.0.1 ^2,5 ] deca-3
-Ene, tricyclo [4.4.0.1 ^2,5 ] undeca-3,7-diene, tricyclo [4.4.0.
1 ^2,5] undec-3,8-diene, tricyclo [4.4.0.1 ^2,5] undec-3-ene, tetracyclo ^{[7.4.0.1 10,13.} 0 ^2,7 ] -trideca-2,4,6-11-tetraene (alias: 1,4
- methano -1,4,4a, 9a- tetrahydrofluorene), tetracyclo ^{[8.4.0.1 11,14.} 0
^3,8 ] -tetradeca-3,5,7,12-11-tetraene (alias: 1,4-methano-1,4,4a, 5,1
0,10a-hexahydroanthracene),

Tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -dodec-3-ene (common name: tetracyclododecene), 8-methyl-tetracyclo [4.4.0.
1 ^2, 5. 17, ¹⁰ ] -dodec-3-ene, 8-ethyl-tetracyclo [4.4.0.1 ^2,5 .
17, ¹⁰ ] -dodec-3-ene, 8-methylidene-tetracyclo [4.4.0.1 ^2,5 . ^{17, 10} ] -dodec-3-ene, 8-ethylidene-tetracyclo [4.
4.0.1 ^2,5 . 1 ^7,10 ] -dodec-3-ene,
8-vinyl-tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -dodec-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] - dodeca-3-ene, 8-methoxycarbonyloxy - tetracyclo [4.4.0.1 ^2, 5. 1 ^7,10 ] -dodeca-3-
Ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . ^{17, 10} ]-dodeca-
3-ene, 8-hydroxymethyl-tetracyclo [4.
4.0.1 ^2,5 . 1 ^7,10 ] -dodec-3-ene,
8-carboxy-tetracyclo [4.4.0.
^12,5 . ^{17 , 10} ] -dodec-3-ene,

8-cyclopentyl-tetracyclo [4.
4.0.1 ^2,5 . 1 ^7,10 ] -dodec-3-ene,
8-cyclohexyl-tetracyclo [4.4.0.1
^2,5 . 17, ¹⁰ ] -dodec-3-ene, 8-cyclohexenyl-tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -dodec-3-ene, 8-phenyl-tetracyclo [4.4.0.1 ^2,5 . ^{17, 10} ] -dodec-3-ene, pentacyclo [6.5.1.1 ^3,6 . 0
^2,7 . 0 ^{9, 13]} pentadeca-3,10-diene,
Pentacyclo [7.4.0.1 ^3,6 . 1 ^{10, 13} .
Norbornene-based monomers such as 0 ^2,7 ] -pentadeca-4,11-diene;

Cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7- Monocyclic cycloalkenes such as methano-1H-indene and cycloheptene; vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane; alicyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene; Is mentioned.

As the aromatic olefin, styrene, α
-Methylstyrene, divinylbenzene and the like.

The alicyclic olefin and / or aromatic olefin can be used alone or in combination of two or more.

The monomers copolymerizable with the alicyclic olefin or the aromatic olefin include ethylene, propylene,
1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1- Hexene, 4,4-dimethyl-1-hexene,
4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene,
Ethylene or α-olefin having 2 to 20 carbon atoms, such as decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene; cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, -Methylcyclohexene, 2
-(2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7
-Cycloolefins such as methano-1H-indene;
Non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and 1,7-octadiene; and the like. These monomers can be used alone or in combination of two or more.

The method for polymerizing the alicyclic olefin and / or the aromatic olefin and the method for hydrogenation as required are not particularly limited, and can be carried out according to known methods.

Specific examples of the alicyclic olefin polymer include, for example, a ring-opened polymer of a norbornene-based monomer and a hydrogenated product thereof, an addition polymer of a norbornene-based monomer, a norbornene-based monomer and a vinyl Addition polymers with compounds, monocyclic cycloalkene polymers, alicyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers and their hydrogenated products, aromatic ring hydrogenated aromatic olefin polymers, etc. No. Among these, a ring-opening polymer of a norbornene-based monomer and a hydrogenated product thereof, an addition polymer of a norbornene-based monomer, an addition polymer of a norbornene-based monomer and a vinyl compound, and an aromatic olefin polymer. An aromatic ring hydrogenated product is preferred, and a hydrogenated product of a ring-opened polymer of a norbornene monomer is particularly preferred.

The alicyclic olefin polymers described above can be used alone or in combination of two or more.

The alicyclic olefin polymer is not particularly limited by its molecular weight. The molecular weight of the alicyclic olefin polymer is determined by gel permeation chromatography (GPC) using cyclohexane or toluene as a solvent. The weight average molecular weight (Mw) in terms of polystyrene is measured.
And usually 1,000 to 1,000,000, preferably 5,000 to 500,000, more preferably 10,000.
The range is from 00 to 250,000. When the weight average molecular weight (Mw) of the alicyclic olefin polymer is in this range, heat resistance, adhesiveness, smoothness of the film, and the like are balanced, which is preferable.

The molecular weight distribution of the alicyclic olefin polymer is as follows:
Weight average molecular weight (Mw) and number average molecular weight (Mw) measured by GPC using cyclohexane or toluene as a solvent
The ratio (Mw / Mn) to n) is usually 5 or less, preferably 4 or less, more preferably 3 or less. The above ranges of the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) and the measuring method are suitably adapted to the norbornene-based polymer, but are not limited thereto. In the case of an alicyclic olefin polymer whose weight-average molecular weight or molecular weight distribution cannot be measured by the above method, a polymer having a melt viscosity and a degree of polymerization sufficient to form a resin layer by a normal melt processing method is used. be able to.

In the present invention, if necessary, a compounding agent can be added to the alicyclic olefin polymer. The compounding agent is not particularly limited as long as it is generally used in the resin industry. For example, a curing agent, a curing accelerator, a curing aid, a filler, a heat stabilizer, a flame retardant, a leveling agent, an antistatic agent Agents, slip agents, anti-blocking agents, anti-fogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, anti-aging agents, ultraviolet stabilizers, ultraviolet absorbers, coloring agents, and the like. , As long as the object of the present invention is not impaired.

The alicyclic olefin polymer may be blended with a soft polymer or another resin, if necessary. Examples of the soft polymer include natural rubber, polybutadiene rubber, polyisoprene rubber, acrylonitrile
Diene rubbers such as butadiene copolymer rubber, styrene / butadiene copolymer rubber, styrene / isoprene copolymer rubber, styrene / butadiene / isoprene terpolymer rubber; ethylene / α such as ethylene / propylene copolymer -Olefin copolymer, propylene and other α-
Saturated polyolefin rubbers such as olefin copolymers; α-olefin / diene copolymers such as ethylene / propylene / diene copolymers, α-olefin / diene copolymers, isobutylene / isoprene copolymers, and isobutylene / diene copolymers Combined rubber; special rubber such as urethane rubber, silicone rubber, polyether rubber, acrylic rubber, ethylene acrylic rubber; styrene / butadiene / styrene / block copolymer rubber; styrene / isoprene /
Aromatic vinyl polymers such as styrene block copolymers and hydrogenated products thereof; urethane thermoplastic elastomers; polyamide thermoplastic elastomers;
A polybutadiene-based thermoplastic elastomer;

Examples of the resin include polyolefins such as polyethylene, polypropylene, polybutene and polypentene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyamides such as nylon 6 and nylon 66; ethylene-ethyl acrylate copolymer; Vinyl copolymer, polycarbonate; and the like.

[0035]

EXAMPLES The molding method of the present invention will be described in more detail with reference to examples.

Example 1 A 14.5 inch size (long side to short side ratio of 4/3)
2.4mm thick part and 0.5mm minimum part
Light guide plate (A / d = about 43,000 mm) ²/ M
m) in a mold for molding the gate cross section S = 110
mm²(Short side 0.5mm, long side 220mm) slit
The gate was provided on the short side of the mold. This mold is used for flow analysis
S / L is about 0.4mm²/ Mm. Mold cap
A V-shaped groove with a depth of 0.1 mm is formed on the main surface
The convex part to form gradually from the thick part to the thin part
The gap is formed to be narrow.

Alicyclic olefin polymer (83 parts by weight of dicyclopentadiene and 17 parts by weight of ethyltetracyclododecene are subjected to ring-opening copolymerization and hydrogenated; hydrogenation rate 99.8%, Tg 102 ° C., melt Flow rate 69g
A composition consisting of 100 parts by weight (280 ° C .: JIS K 6719) and 1 part by weight of SEBS (hydrogenated styrene-butadiene-styrene block copolymer) at a resin temperature of 260 ° C. in a mold at a resin temperature of 260 ° C. A filling pressure of 250 kgf / cm ^{2 is} applied to a mold having a temperature of 70 ° C. and a mold clamping force of 200 tons.
Then, the clamping force was increased to 450 tons, the holding pressure was set to 900 kgf / cm ² , and a wedge-shaped plate was obtained.
V-shaped grooves were accurately carved in the main surface of the plate. The brightness uniformity was about 95%.

Example 2 In Example 1, the gate was replaced with the long side of the mold (thick portion).
A wedge-shaped plate was obtained in the same manner as in Example 1 except for the provision of the above. This mold has an S / L of about 0.6 mm ² by flow analysis.
/ Mm. V-shaped grooves were accurately carved in the main surface of the plate. The brightness uniformity was about 95%.

Comparative Example 1 In Example 2, the gate cross-sectional area was 35 mm ² (short side 0.
A wedge-shaped plate was obtained in the same manner as in Example 2 except that a standard gate (7 mm, long side 50 mm) was provided on the short side of the mold. This mold has an S / L of about 0.0 by flow analysis.
It was 3 mm ² / mm. Although a V-shaped groove was cut in the main surface of the plate, the groove was sharpened in a portion where the groove interval was narrow.
The brightness uniformity was about 70%.

[0040]

According to the method of the present invention, a wide-area thin-walled product in the form of a plate (wedge), sheet, or film can be formed with good transferability from a mold. The molded product obtained by this method has less luminance unevenness and is suitable for an optical member for a liquid crystal display device.

Claims (6)

[Claims] 1. A ratio S / L (mm ² / mm) of a cross-sectional area S of a gate to a maximum flow length L of a molten resin in a cavity.
A method for molding a large-area thin-walled molded product, which is injection-molded using a mold having a value of 0.1 or more. 2. An injection filling pressure of 50 to 600 kgf / cm is applied to a mold clamped with a mold clamping force of 50 to 250 tons.
^{2. A} method of forming a large-area thin-walled molded product, wherein the resin is filled and then the mold clamping force is increased to 300 to 500 tons and molded. 3. The molding method according to claim 1, wherein the mold is capable of forming a wedge-shaped large-area thin-walled molded product. 4. A molding method according to claim 3, wherein a gate is provided at a maximum thickness portion or a minimum thickness portion of a mold capable of forming a wedge-shaped large-area thin-walled molded product, and injection molding is performed. 5. A mold temperature at which a resin is filled in a mold,
Set in a range from a temperature 70 ° C. lower than the glass transition temperature of the resin to a temperature 40 ° C. higher than the glass transition temperature,
The molding method according to claim 1. 6. The molding method according to claim 1, wherein the resin is an alicyclic olefin polymer.