JP2001038773A - Method for molding molded article for optical part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a large-sized and thin-walled molded object excellent in the transfer properties of a fine and complicated shape, surface accuracy and transparency without generating appearance inferiority such as a sink, foaming or seizing by injection-molding a resin compsn. containing an alicyclic structure- containing polymer by using a hot runner type mold. SOLUTION: In a mold apparatus 3, a manifold block 9 and a fixed metal fitting 5 are fixed to a fixed platen 4 and a movable metal fitting 7 is fixed to a movable platen 6. A cavity 71 is formed in the movable metal fitting 7 and the first runner 91 communicating with a recessed part 91 is formed to the manifold block 9 and a nozzle 21 is inserted in the recessed part 91. A first heater is incorporated in close vicinity to the first runner 92 to form a hot runner 93. Further, the second runner 52 communicating with the first runner 92 is provided to the fixed mold 5. A second heater 51 is attached to the outer peripheral part of the second runner 52 to form a hot runner 53. By this constitution, the molten resin flowing in the hot runners 93, 53 is indirectly heated from the outside and the flow characteristics thereof can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a molded article for optical parts, and more particularly to a method for molding a large and thin molded article for optical parts.

[0002]

2. Description of the Related Art Optical lenses, optical disks, optical sheets,
As a material of a molded article for optical parts such as a light guide plate, a light diffusion plate, and a prism, polycarbonate (PC), PMMA,
Alicyclic structure-containing polymers and the like are known. PC, PMM
As a method for molding an optical component using A, an injection molding method is generally used.

Conventionally, when injection molding PC or PMMA, a so-called cold runner system and a hot runner system are known. Of these, the hot runner method is useful for increasing the fluidity of the resin because the molten resin can flow into the mold while it is heated, but may cause molding defects such as burrs and overpacking. In the molding of PC and PMMA, a method of increasing the temperature of the injection cylinder by a cold runner method has generally been adopted.

On the other hand, polymers having an alicyclic structure include PC and PM.
It is known as a resin having higher fluidity than MA and having excellent transferability of finer shapes.

Incidentally, the shape of the above-mentioned optical component has become increasingly larger and thinner in recent years, and it has been required to have a complicated and fine shape. In order to mold such an optical component at a high transfer rate, even if an alicyclic structure-containing polymer having excellent fluidity is used, it is difficult to increase the fluidity by simply increasing the cylinder temperature as in the past. In some cases, problems such as foaming, burning, and the like may occur, and further, the transparency of the resin may be reduced due to coloring of the resin.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to produce a large and thin optical component molded article having excellent transferability, surface accuracy and transparency of a fine and complicated shape without sink, foaming and burning. It is to provide a method for molding.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have found that a hot runner type mold is used when injection molding an alicyclic structure-containing polymer. It can significantly improve only the fluidity of the molten resin immediately before injection while suppressing thermal deterioration of the polymer containing alicyclic structure while melting, without molding defects such as burrs and overpacking, transferability, surface accuracy, and transparency. It has been found that a molded article for an optical component having a superior shape, a complicated shape, a thin thickness, and a large size can be obtained. Further, they have found that a molded article having a fine pattern excellent in transferability can be obtained even when a mold having a fine pattern is used. The present invention has been completed based on these findings.

Thus, according to the present invention, there is provided a method for molding a molded article for optical parts, which comprises a step of injection-molding a resin composition containing a polymer having an alicyclic structure using a hot runner type mold. .

[0009]

Embodiments of the present invention will be described below.

Alicyclic Structure-Containing Polymer As the alicyclic structure-containing polymer in the present invention, a polymer containing an alicyclic structure in a repeating unit of the polymer is used. The alicyclic structure-containing polymers include those having an alicyclic structure in a main chain, those having a side chain, and those having both a main chain and a side chain, but have mechanical strength, heat resistance and moldability. From the viewpoint of the above, those having an alicyclic structure in the main chain are preferable. The alicyclic structure-containing polymer used in the present invention is preferably a thermoplastic one.

Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferred from the viewpoint of mechanical strength and heat resistance. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, and more preferably 5 to 15, when the mechanical strength, The properties of heat resistance and moldability are highly balanced,
It is suitable.

The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use, but is usually 30% by weight or more, preferably 50% by weight.
% By weight, more preferably 70% by weight or more. If the proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is too small, the heat resistance is poor, which is not preferable.
The remainder other than the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is not particularly limited, and is appropriately selected depending on the purpose of use.

Specific examples of the polymer resin having such an alicyclic structure include (1) a norbornene-based polymer, (2) a monocyclic olefin-based polymer, and (3) a cyclic conjugated diene-based polymer. And (4) vinyl alicyclic hydrocarbon-based polymers, and hydrogenated products thereof. Among these, from the viewpoint of mechanical strength, thermal stability, and moldability, norbornene-based polymers and their hydrogenated products, cyclic conjugated diene-based polymers and their hydrogenated products, and the like are preferred, and norbornene-based polymers and their Hydrogenates are more preferred.

(1) Norbornene-based polymer The norbornene-based polymer used in the present invention is, for example,
JP-A-3-14882 and JP-A-3-12213
No. 7 publication and the like, specifically, a ring-opening polymer of a norbornene-based monomer and a hydrogenated product thereof, an addition polymer of a norbornene-based monomer,
An addition-type copolymer of a norbornene-based monomer and another monomer copolymerizable with the norbornene-based monomer is exemplified. Among these, a ring-opened polymer of a norbornene-based monomer and a hydrogenated product thereof are preferable, and a hydrogenated product of a ring-opened polymer of a norbornene-based monomer is particularly preferable in order to highly balance heat resistance and chemical resistance.

Examples of the norbornene-based monomer include bicyclo [2,2,1] -hept-2-ene (common name: norbornene), 5-methyl-bicyclo [2,2,1] -hept-2-ene, , 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-
Carbonyl-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-methoxycarbonyl-bicyclo [2,2,1] -hept-2-ene, 5-ethoxy Carbonyl-bicyclo [2,2,1]
-Hept-2-ene, 5-methyl-5-ethoxycarbonyl-bicyclo [2,2,1] -hept-2-ene, bicyclo [2,2,1] -hept-5-enyl-2-methylpro Pionate, bicyclo [2,2,1] -hept-
5-enyl-2-methyloctaneate, bicyclo [2,
2,1] -hept-2-ene-5,6-dicarboxylic anhydride, 5-hydroxymethyl-bicyclo [2,2,1]
-Hept-2-ene, 5,6-di (hydroxymethyl)
-Bicyclo [2,2,1] -hept-2-ene, 5-hydroxy-i-propyl-bicyclo [2,2,1] -hept-2-ene, bicyclo [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 , 1 ^{2,5,0 1,6} ] -deca-3,7-diene (commonly used dicyclopentadiene), tricyclo [4,
3,1 ^{2,5, 0 1,6]} - dec-3-ene, tricyclo ^{[4,4,1 2,5, 0 1,6]} - undec-3,7
- diene, tricyclo ^{[4,4,1 2,5, 0 1,6]}
-Undeca-3,8-diene, tricyclo [4,4,1
^{2,5, 0 1,6]} - undec-3-ene, tetracyclo ^{[7,4,1 10,13,} 0 ^{1,9, 0 2,7]} - trideca -2,4,6-11- tetraene ( 1,4-methano -1,4,4a, also referred 9a- tetrahydrofluorene), tetracyclo ^{[8,4,1 11,14,} 0
^{1, 10, 0 3,8]} - tetradeca -3,5,7,12
11-tetraene (1,4-methano-1,4,4a,
5,10,10a- also called hexa hydro anthracene), tetracyclo ^{[4,4,1 2,5, 1 7,10,}
0] - dodeca-3-ene (also simply referred to as tetracyclododecene), 8-methyl - tetracyclo [4,4,1 ^{2
, 5, 1 7,10,} 0] - dodeca-3-ene, 8-methyl - tetracyclo ^{[4,4,1 2,5, 1 7,10,}
0] - dodeca-3-ene, 8-ethyl - tetracyclo ^{[4,4,1 2,5, 1 7,10,} 0] - dodeca-3
Ene, 8-methylidene-tetracyclo [4,4,1
^{2,5, 1 7,10,} 0] - dodeca-3-ene, 8-ethylidene - tetracyclo ^{[4,4,1 2,5,} 1
^7,10, 0] - dodeca-3-ene, 8-vinyl - tetracyclo ^{[4,4,1 2,5, 1 7,10,} 0] - dodeca-3-ene, 8-propenyl - tetracyclo [4,
4,1 ^{2,5, 1 7, 10,} 0] - dodeca-3-ene,
8-methoxycarbonyl-tetracyclo [4,4,1
^{2,5, 1 7,10,} 0] - dodeca-3-ene, 8-methyl-8-methoxycarbonyl - tetracyclo [4,
4,1 ^{2,5, 1 7,10,} 0] - dodeca-3-ene,
8-hydroxymethyl-tetracyclo [4,4,1
^{2,5, 1 7,10,} 0] - dodeca-3-ene, 8-carboxy - tetracyclo ^{[4,4,1 2,5,} 1
^7,10, 0] - dodeca-3-ene, 8-cyclopentyl-- tetracyclo ^{[4,4,1 2,5, 1 7,10,}
0] - dodeca-3-ene, 8-cyclohexyl - tetracyclo [4,4,1 ^{2, 5, 1 7,10,} 0] - dodeca-3-ene, 8-cyclohexenyl - tetracyclo [4,4,1 ^{2,5, 1 7,10,} 0] - dodeca-3
Ene, 8-phenyl-tetracyclo [4,4
1 ^{2,5, 1 7,10,} 0] - dodeca-3-ene, pentacyclo ^{[6,5,1 1,8,} 1 ^{3,6, 0 2,7,} 0
^9,13] - pentadeca-3,10-diene, pentacyclo ^{[7,4,1 3,6, 1 10,13, 0 1,9,} 0
^And norbornene-based monomers such as [ ^2,7 ] -pentadeca-4,11-diene. These norbornene monomers may be used alone or in combination of two or more.

The ring-opened polymer of these norbornene-based monomers can be obtained by polymerizing the above-mentioned norbornene-based monomer in the presence of a known ring-opening polymer catalyst and, if necessary, hydrogenating it.

The addition (co) polymer of a norbornene-based monomer or another monomer copolymerizable with the norbornene-based monomer can be prepared, for example, by adding a monomer component to a titanium, zirconium, or vanadium compound in a solvent or without a solvent. In the presence of a catalyst system comprising an organoaluminum compound, the polymerization temperature is usually -50 ° C to 100 ° C,
It can be obtained by a method of (co) polymerization at a polymerization pressure of 0 kg / cm ² .

Other copolymerizable monomers include:
For example, 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-
Carbon such as 1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene Equations 2 to 20
Olefin; cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano Cycloolefins such as -1H-indene; 1,4-hexadiene, 4-methyl-
Non-conjugated dienes such as 1,4-hexadiene, 5-methyl-1,4-hexadiene and 1,7-octadiene; and the like are used. Among these, α-olefins, particularly ethylene, are preferred. These other copolymerizable monomers can be used alone or in combination of two or more. When the norbornene-based monomer and the other copolymerizable monomer are addition-copolymerized, the ratio of the binding unit derived from the norbornene-based monomer to the binding unit derived from the other copolymerizable monomer in the addition copolymer is not sufficient. , Usually 30:70 to 99: 1 by weight,
Preferably 50:50 to 97: 3, more preferably 7
It is appropriately selected so as to be in the range of 0:30 to 95: 5.

(2) Monocyclic Cyclic Olefin Polymer Examples of the monocyclic cycloolefin polymer include monocyclic cycloolefin polymers such as cyclohexene, cycloheptene and cyclooctene disclosed in JP-A-64-66216. Can be used.

(3) Cyclic conjugated diene-based polymer The cyclic conjugated diene-based polymer is described in, for example,
The cyclic conjugated diene-based monomers such as cyclopentadiene and cyclohexadiene disclosed in JP-A-136057 and JP-A-7-258318 are used as 1,2- or 1,2-
4-Polymerized polymers and hydrogenated products thereof can be used.

(4) Vinyl alicyclic hydrocarbon polymer Examples of the vinyl alicyclic hydrocarbon polymer include vinyl cyclohexene and vinyl cyclohexane disclosed in JP-A-51-59989. Polymers of alicyclic hydrocarbon monomers and hydrogenated products thereof, vinyls such as styrene and α-methylstyrene disclosed in JP-A-63-43910 and JP-A-64-1706. A hydrogenated product of the aromatic ring portion of the polymer of the aromatic monomer can be used.

The molecular weight of the alicyclic structure-containing polymer used in the present invention is appropriately selected according to the purpose of use. Gel permeation of a cyclohexane solution (a toluene solution when the polymer resin does not dissolve) is used. A weight average molecular weight in terms of polyisoprene or polystyrene measured by a chromatographic method, usually in the range of 5,000 to 500,000, preferably 8,000 to 200,000, more preferably 10,000 to 100,000. At some point, mechanical strength and moldability are highly balanced and suitable.

The Tg of the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use.
It is usually in the range of 80 ° C or higher, preferably 90 ° C to 250 ° C, more preferably 100 ° C to 200 ° C. Within this range, heat resistance and moldability are highly balanced and suitable.

JIS K of the alicyclic structure-containing polymer used in the present invention at 280 ° C. under a load of 2.16 kgf
The melt flow rate measured by 6719 may be appropriately selected depending on the purpose of use, but is usually 10 to 200 g.
/ 10 min. , Preferably 20 to 150 g / 10 mi
n. More preferably, 50 to 120 g / 10 min. Range. When the melt flow rate is in the above range, the flowability of the molten resin can be improved and molding defects such as generation of burrs can be reduced, which is preferable.

In the present invention, in addition to the alicyclic structure-containing polymer, a resin, a soft polymer, an additive and the like can be blended as required.

As the resin, polyvinyl chloride, polymethyl methacrylate, polystyrene, polymethyl methacrylate styrene copolymer, polyacrylonitrile, polyacrylonitrile styrene copolymer, high impact polystyrene (HIPS), acrylonitrile butadiene styrene copolymer (ABS resin), amorphous resins such as polycarbonate, polyarylate, polysulfone, polyethersulfone, and polyphenylene ether; high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, polypropylene, polypropylene, polymethylpentene, super Chain polyolefin polymers such as high molecular weight polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, aromatic Polyester polymers such as polyester; polyamide polymers such as nylon 6, nylon 66, nylon 12, and polyamideimide; vinyl polymers such as polyvinyl alcohol and polyvinylidene chloride; fluorine such as polyvinylidene fluoride and polytetrafluoroethylene. And crystalline resins whose crystalline melting points are observed by thermal measurement, such as system polymers, polyacrylonitrile, syndiotactic polystyrene, polyoxymethylene, polyphenylene sulfide, polyetheretherketone, and liquid crystal polymers.

By blending these resins, the fluidity during molding, the mechanical strength of the molded article, and the heat resistance are further improved, which is preferable.

The soft polymer is a polymer having a Tg of usually 30 ° C. or lower. In the case of a polymer having a plurality of Tg or a polymer having both Tg and melting point (Tm), a polymer having the lowest Tg of 30 ° C. or lower is included in the soft polymer.

Examples of such a soft polymer include (a) an olefin-based soft polymer mainly composed of α-olefin such as ethylene and propylene, (b) an isobutylene-based soft polymer mainly composed of isobutylene, and (c) butadiene. , A diene-based soft polymer mainly comprising a conjugated diene such as isoprene, (d) a soft polymer having a silicon-oxygen bond as a skeleton (organic polysiloxane), (e) α, β
-A soft polymer consisting mainly of unsaturated acids and their derivatives,
(F) a soft polymer mainly composed of an unsaturated alcohol and an amine or an acyl derivative or acetal thereof,
(G) a polymer of an epoxy compound, (h) a fluorine-based rubber,
(I) Other soft polymers and the like.

Among the above soft polymers, (a), (b),
The soft polymer of (c), more preferably the diene-based soft polymer of (c), further preferably a hydrogenated product of a diene-based soft polymer in which the carbon-carbon unsaturated bond of the conjugated diene bond unit is hydrogenated. It is preferable because it is excellent in rubber elasticity and excellent in mechanical strength, flexibility and dispersibility.

Preferred examples of the diene-based polymer include hydrogenated homopolymers such as polybutadiene, and hydrogenated random copolymers such as butadiene-styrene copolymer; butadiene-styrene-block copolymer; And hydrogenated block copolymers such as styrene / butadiene / styrene / block copolymers, isoprene / styrene / block copolymers, and styrene / isoprene / styrene / block copolymers. By blending these soft polymers, the mechanical strength of the molded product can be further improved and the residual stress can be reduced, which is preferable.

The above resins and soft polymers are used alone or in combination of two or more. The amount of these other polymers in the total weight of the alicyclic structure-containing polymer is appropriately selected within a range not to impair the object of the present invention, and is usually less than 50% by weight, preferably 30% by weight or less,
It is more preferably at most 10% by weight.

The additives are not particularly limited as long as they are generally used in the resin industry. For example, stabilizers such as antioxidants, ultraviolet absorbers, light stabilizers and heat stabilizers; Fillers such as fillers and inorganic fillers; coloring agents such as dyes and pigments; near-infrared absorbers, plasticizers, lubricants, antistatic agents, and flame retardants. These additives can be used alone or in combination of two or more, and the amount added is appropriately selected within a range not to impair the object of the present invention.

In the present invention, among the above additives,
By adding a specific amount of an antioxidant to the alicyclic structure-containing polymer, it is possible to obtain a molded article for an optical component with less decrease in strength. The antioxidant used is not particularly limited, and examples thereof include a phenolic antioxidant, a phosphorus-based antioxidant, a thioether-based antioxidant, and a lactone-based antioxidant. The inhibitor is excellent in terms of heat resistance and the like of the molded article.

The compounding amount of the antioxidant is usually 0.001 to 100 parts by weight of the alicyclic structure-containing polymer.
15 parts by weight, preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight. If the amount of the antioxidant in the alicyclic structure-containing polymer is excessively large, the transparency of the molded body may decrease. On the contrary, if the amount is too small, the impact resistance of the molded body due to deterioration of the resin may be reduced. Performance may be reduced.

Hot runner type mold The hot runner type mold used in the present invention is a mold provided with a means for heating the molten resin passing through the runner. Here, the runner is located between the sprue where the molten resin injected from the nozzle of the injection molding machine first passes and the gate at the entrance of the mold cavity, and moves the molten resin from the sprue to the gate. It is a passage to be made. Heating the molten resin that passes through the runner allows the molten resin to flow into the cavity from the mold gate without increasing the viscosity of the molten resin. The transferability of the molded body is improved as a result.

In addition, since the fluidity of the molten resin immediately before injection can be improved without increasing the cylinder temperature more than necessary, coloring or the like due to the heat history of the molten resin can be suppressed, and the transparency of the molded body can be maintained.

The means for heating the runner is not particularly limited as long as it can heat the molten resin in the runner from inside and outside, but an external means for heating the flow path (runner manifold) of the molten resin connecting the nozzle and the runner. Examples of the heating method include an internal heating method in which a heating element is provided at the center of the runner. Although the external heating method has a small heat loss from the manifold to the outside, the temperature of the molten resin in the runner is uniform, the pressure loss in the resin flow can be reduced, and the internal heating method has the advantage of good thermal efficiency. In the present invention, it is preferable to use an external heating method in order to reduce the pressure loss due to the resin flow and improve the transferability.

The specific structure of such a hot runner type mold will be described below with reference to the drawings.

FIG. 1A is a schematic cross-sectional view showing an externally heated hot runner type injection molding die according to an embodiment of the present invention, in a state where the die is clamped, and a cylinder tip portion of the injection molding machine.

In FIG. 1, the mold 3 has a fixed platen 4 and a movable platen 6, and a manifold block 9 and a fixed side mold 5 are fixed to the fixed platen 4 in this order. A movable die 7 is fixed to the movable platen 6. Movable mold 7 is movable plate 6
Thereby, it is configured to be movable to a mold clamping position and a mold opening position with respect to the fixed mold 5. At the mold clamping position of the mold apparatus 3, the movable mold 7 is combined with the fixed mold 5 at a parting surface 8 to form a cavity 71 therein.

The manifold block 9 has a curved concave portion 91 and a first runner (first resin guiding portion) 92 communicating with the concave portion 91. The concave portion 91 has a nozzle of the injection device main body 2. 21 is inserted.

In the present embodiment, a first heater (not shown) is provided in the manifold block 9 by the first runner 9.
2, and the first runner 92 constitutes a hot runner 93 in the present embodiment.
That is, by operating the first heater incorporated in the manifold block 9 to heat the manifold block 9 and indirectly externally heating the molten resin flowing in the first runner 92, the flow characteristics are improved. .

The fixed mold 5 is connected to the manifold block 9.
And the second runner 52 that communicates with the first runner 92. In the present embodiment, an external heating type hot runner 53 in which the second heater 51 is attached to the outer peripheral portion of the second runner 52 is provided. Adopting the external heating method is preferable because the stagnation portion is small and the cross-sectional area as an effective portion through which the molten resin flows is large, so that the pressure loss is small and the resin is less likely to be thermally degraded. Then, the second runner 52 is heated by operating the second heater 51 attached to the outer periphery of the second runner 52, and as a result, the molten resin flowing in the hot runner 53 is indirectly externally heated to the fluidity. Is improved.

The heater as the means for heating is not particularly limited, and may be a heater for circulating a heating fluid in addition to a heater for heating by supplying electricity to the heating element. The hot runner temperature (heater temperature) is usually 50 to 400 ° C, preferably 100 to 350 ° C, and more preferably 150 to 320 ° C.
° C, particularly preferably in the range of 200 to 300 ° C. By adjusting the temperature in this range, the balance between the fluidity of the resin and the heat deterioration resistance of the resin remaining in the runner is achieved. The shape of the cross section of the runner is not particularly limited, but a circular shape is preferable from the viewpoint of fluidity.
The diameter of the runner is not particularly limited, but is usually 1 to 15
mm, preferably 2 to 12 mm, more preferably 2.5 mm
〜１０10 mm. By setting the diameter in this range, the fluidity of the resin at the time of molding can be ensured, and a sufficient amount of heat can be transmitted to the passing resin.

The movable mold 7 has a third runner 72 communicating with the second runner 52 of the fixed mold 5, and the third runner 72 passes through a gate (resin injection portion) 73 and has a cavity. 71.

The gate includes an open gate system and a valve gate system. The open gate method is a gate method in which a gate portion has no mechanical gate opening / closing mechanism and is always open. The valve gate system is a gate system having a mechanism (valve) for mechanically opening and closing the gate, opening the gate at the time of injection, and closing the gate after the injection is completed. It is preferable to use a valve gate method since gate sealing can be suitably performed after resin is injected and filled into the cavity. Also, in the valve gate,
A single-stroke process is particularly preferable because it can increase the cycle time.

FIG. 1B is a schematic partial sectional view of an internally heated hot runner according to another embodiment of the present invention.
In FIG. 1B, a second heater 51 'is incorporated in the center of a second runner 52' to form a hot runner 53 '. A first heater in the manifold block,
Other basic structures such as the first runner, the heating temperature of the heater, and the like are the same as those in the case of the external heating method.

Molding Method In the present invention, a molded article for an optical component is obtained by injection molding a resin composition containing the alicyclic structure-containing polymer and, if necessary, the other components, using the hot runner mold. Is molded. Mixing of the alicyclic structure-containing polymer and other components can be performed according to a conventional method, for example, a method of kneading a resin in a molten state with a mixer, a twin-screw kneader, a roll Brabender, an extruder, or the like. A method of dissolving or dispersing in an appropriate solvent to remove the solvent by a coagulation method, a casting method, or a direct drying method. In the present invention, other components such as a twin-screw kneader or a direct drying method are used. It is preferable that the resin strand melt-extruded after mixing is pelletized by a pelletizer and used as a molding material. The obtained pellets are usually used within 6 hours, preferably within 4 hours, and more preferably within 2 hours, before molding, for the purpose of minimizing molding defects such as coloring of the molded product, burning and occurrence of silver streaks and the like. It is preferable to perform preliminary drying within the range.

The resin composition molding material obtained by pelletizing in this manner is preliminarily dried as described above, if necessary, then put into a hopper of an injection molding apparatus, and melted by a screw in a heating cylinder. It is sent to the tip while being transformed.

Next, the screw is advanced toward the nozzle 21 at a predetermined speed (injection speed), and the stored molding material is pressed at a predetermined pressure (injection pressure) into the first runner 9.
2, the second runner 52, the third runner 72 and the gate 7
3, the cavity 71 is filled and cooled and solidified while keeping the pressure for a certain period of time. Then, the movable mold 7 is opened and the molded product is taken out. The molten plasticized resin injected from the nozzle 21 is also heated while flowing through the inside of the hot runner, so that the molten plasticized resin can be held without deteriorating the flow characteristics until it is injected and filled into the cavity 71 of the mold.

In the present invention, the temperature of the injection cylinder varies depending on the type of the alicyclic structure-containing polymer.
Usually 150 to 400 ° C, preferably 180 to 360 ° C,
More preferably 190 to 330 ° C, further preferably 2
20-300 ° C. By setting the cylinder temperature within this range, the fluidity of the resin is improved and deterioration due to decomposition or the like is reduced, which is preferable.

The mold surface temperature of the inner peripheral surface of the cavity 71 is usually set at a temperature lower than the Tg of the alicyclic structure-containing polymer, and is preferably (Tg-0) ° C. to (Tg-100).
° C, more preferably (Tg-20) ° C to (Tg-60)
It is in the range of ° C. When the mold surface temperature is in this range,
This is preferable because the distortion of the molded article can be reduced, the releasability is improved, and the defects of the molded article are reduced.

The injection speed is usually 3.2 × 10 ⁻⁷ to 8.
0 × 10 ⁻⁵ m ³ / sec, preferably 6.2 × 10
^{−7 to} 6.2 × 10 ⁻⁵ m ³ / sec, more preferably 8.0 × 10 ^{−7 to} 4.2 × 10 ⁻⁵ m ³ / sec. When the injection speed is in this range, resin decomposition due to shearing during hot runner molding can be suppressed.

The injection pressure is usually 500 to 1,500 kgf
/ Cm ² , preferably 700 to 1,500 kgf / cm
² . By setting the injection pressure in this range, there is less possibility that the molten resin is decomposed due to heat generated by shearing, and the molded article is less likely to sink.

The holding pressure is a pressure applied for a certain period of time after the mold is substantially filled by the injection pressure until the gate portion of the mold is completely cooled and solidified. The upper limit of the holding pressure is generally set within the range of the mold clamping pressure of the mold, but is usually 2,000 kgf / cm ² , preferably 1,700 kg.
f / cm ² , more preferably 1,500 kgf / cm ²
It is. By setting the upper limit of the holding pressure to the above value, defects such as distortion of the molded product can be reduced. The lower limit of the holding pressure is usually 100 kgf / cm ² , preferably 120 kgf / c.
m ² , more preferably 150 kgf / cm ² . By setting the lower limit of the holding pressure to the above value, sinkage of a molded product can be prevented, the molding shrinkage can be reduced, and a molded article for an optical component having excellent dimensional accuracy can be obtained.

Molding for optical parts In the present invention, when a hot runner type mold having fine irregularities in the mold cavity is used, molding for optical parts having fine surface irregularities excellent in transferability is performed. The body is obtained.

The concave and convex shape is preferably a fine concave and convex shape such that the depth and width of the concave portion and the height and width of the convex portion are from submicron to several hundred microns. It is more preferable that the ridges and valleys and the pit-shaped concave portions formed by the above have a relatively acute angle portion.

As a specific example of the irregular shape, when the irregular shape units are regularly arranged to form a fine irregular shape, the constituent units are prismatic, cubic, rectangular, cylindrical, and elliptical. , A spherical shape or an aspherical shape, and more specifically, for example, a prism shape, a condensing lens shape, a groove shape, a stippled shape, etc., preferably a fine prism, a fine lens shape. Yes,
More preferably, it is a fine grain prism shape or a fine lens shape in a submicron unit.

Specific examples of the molded article for an optical component having an uneven shape on the surface and being thin include, for example, a light-collecting sheet such as a prism sheet and a lens sheet, a diffusion sheet, and a light guide plate. In particular, the molding method of the present invention,
It is suitable for application to the manufacture of a light guide plate.

Light guide plate As the light guide plate, a side light type or a direct type light guide plate can be mentioned, and the molding method of the present invention is more suitable for producing a thin and fine side light type light guide plate. .

The sidelight type light guide plate has at least one light incident surface for receiving light from at least one light source on a side surface, a light reflecting surface for reflecting the incident light, and a reflected light. Having an emission surface for emitting
One-light type, two-light type, and the like can be given. The shape of the light guide plate is not particularly limited, and may be a flat plate shape, a wedge plate shape, or another shape, but is preferably a wedge plate shape. This is because the shape of the wedge plate further reduces the weight of the light guide plate and the effective use of light. In this case, the tip of the wedge may be flat, curved, or substantially not forming a surface, but is preferably flat. This is because, if the wedge tip is flat, the light can be more effectively used. It should be noted that a wedge-shaped light guide plate of a so-called two-lamp type, in which the wedge plate shapes are arranged such that the thin portions face each other and one plate is formed, and two light sources are provided on the left and right light incident surfaces, is also used. Included in the light guide plate obtained by the invention. Such a wedge-shaped light guide plate is one of the shapes that can be suitably molded by the molding method using the hot runner type mold of the present invention. The thickness of the wedge plate is usually 0.5 to 10 mm, preferably 1 to 5 mm on the side of the thick part, and 0.1 to 5 mm, preferably 0 on the side of the thin part on the opposite side. .1 to 2
mm. The angle of inclination of the light reflecting surface with respect to the light incident direction, which is determined by the thickness of both sides and the length of the light guide plate, is generally 0.1 to 15 degrees, preferably 0.2 to 10 degrees. By using a wedge-shaped light guide plate having an inclination angle in this range, it is possible to appropriately balance the thinness of the light guide plate itself and the achievement of high luminance by effective use of light.

On the light reflecting surface and / or the light emitting surface of the light guide plate, for example, patterns such as light diffusion / reflection such as microdots and V-shaped grooves by graining may be formed.

The shape of the V-shaped groove does not need to be a regular V-shape composed of a perfect plane and a plane, but may be a substantially V-shape. The lengths of the two groove surfaces forming the regular V-shaped groove and the substantially V-shaped groove may be the same or different, and may be set as appropriate. Further, the direction of the groove is preferably arranged so that the arrangement density becomes gradually sparse to dense as the distance from the light source increases, and even if the groove is elongated in a direction substantially parallel to the incident direction of the light, it is preferably in a substantially vertical direction. Although it may be formed to be elongated, it is more preferable that it is formed to be elongated in a substantially vertical direction at any position on the light reflecting surface. In this case, it is more preferable that the length of the groove is formed over the entire width of the light reflecting surface and / or the light emitting surface of the light guide plate in the direction.

The use of the light guide plate is not particularly limited, but for example, a laptop type, a notebook type, a book type,
OA equipment such as a personal computer such as a palmtop type, OA equipment such as a word processor, home electric appliances such as a liquid crystal television for a wall hanging, etc., a light source used in a planar light source device used as a backlight for an illuminated signboard, a light table, a viewer and other display devices. Means light plate.

[0066]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following, “parts” and “%” are based on weight unless otherwise specified. The methods for measuring various physical properties in the following Production Examples, Examples and Comparative Examples are as follows.

Measurement of Physical Properties of Resin (1) The weight average molecular weight (Mw) was determined by gel permeation chromatography (GP) using cyclohexane as a solvent.
It was measured as a polyisoprene conversion value by C). (2) The hydrogenation rate (nuclear hydrogenation rate) of the main chain and the aromatic ring is
^It was measured by ¹ H-NMR. (3) The glass transition temperature (Tg) was measured based on JIS-K7121. (4) The melt flow rate (MFR) was measured at 280 ° C. and a load of 2.16 kgf in accordance with JIS-K6719.

Evaluation Method of Formability 100 light guide plates were formed under the conditions of the following examples.
Then, out of these 100, what percentage of the pattern transfer was good was evaluated.

It was determined whether or not appearance defects such as sink marks, burns and foaming were observed on the surface of the light guide plate.
It was judged visually.

Further, the presence or absence of coloring due to thermal deterioration of the light guide plate was observed, and those without coloring were determined to have good transparency.

Production Example of Resin [Production Example 1] Under a nitrogen atmosphere, 8-ethyltetracyclo [4.4.1 ^2,5 . ^17.10 . 0] -dodeca-3-
15 parts of ene (hereinafter also referred to as ETCD) and 85 parts of tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (dicyclopentadiene, hereinafter also referred to as DCP)
In the presence of 1.20 parts of 1-hexene as a molecular weight regulator,
Polymerization was carried out in 250 parts of dehydrated cyclohexane using a known metathesis ring-opening polymerization catalyst. Subsequently, hydrogenation was performed by a known method to obtain a hydrogenated ETCD / DCP ring-opening copolymer. When the copolymerization ratio of each norbornene in the polymer was calculated from the residual norbornene composition (by gas chromatography) in the solution after polymerization, ETCD /
DCP = 15/85 was almost equal to the charge composition. The hydrogenated product of this ring-opened polymer had a Mw of 27,800, a hydrogenation rate of 99.9%, a Tg of 106 ° C., and an MFR of 75 g / 1.
0 min. Met.

An anti-aging agent (Ilganox 10 manufactured by Ciba-Geigy) was added to 100 parts of the hydrogenated ring-opening polymer.
10) 0.2 part and a soft polymer (ToughTech H manufactured by Asahi Kasei Corporation)
1052) 0.2 parts were added, and a twin-screw kneader (TEM-35B, manufactured by Toshiba Machine Co., screw diameter 37 mm, L / D = 3)
2. Screw rotation speed 250 rpm, resin temperature 240
At a feed rate of 10 kg / hour) and extruded into pellets.

[Production Example 2]
ETC was performed in the same manner as in Production Example 1 except that the ETC was changed to 00 parts.
A hydrogenated D ring-opened polymer was obtained. This ring-opened polymer hydrogenated product had a Mw of 33,500, a hydrogenation rate of 99.9%,
Tg is 140 ° C., MFR is 40 g / 10 min. Met. Except for using this polymer, pelletization was performed in the same manner as in Production Example 1.

[Production Example 3] A hydrogenated ETCD ring-opening polymer of 100 parts of ETCD was obtained in the same manner as in Production Example 2 except that 1-hexene was changed to 1.0 part. This ring-opened polymer hydrogenated product had a Mw of 38,000 and a hydrogenation rate of 9
9.9%, Tg 140 ° C., MFR 25 g / 10 mi
n. Met. Production Example 1 except that this polymer was used
And pelletized in the same manner.

[Production Example 4] ETCD / DCP was prepared in the same manner as in Production Example 1 except that 1-hexene was changed to 0.9 part.
= 15/85 hydrogenated ETCD / DCP ring-opening copolymer. The hydrogenated product of this ring-opening copolymer had an Mw of 37,
000, hydrogenation rate 99.9%, Tg 103 ° C, M
FR is 25 g / 10 min. Met. Except for using this polymer, pelletization was performed in the same manner as in Production Example 1.

[0076] The pellets of Example 1 Production Example 1, by using the external heating method Hot runner injection molding apparatus equipped with a mold having a hot runner shown in FIG. 1 (A), the replacement of the molding machine of the resin A light guide plate 1 as shown in FIG.
0 was molded. The hot runner part is a valve
The gate is sealed after injection. The molding conditions were as follows: a mold temperature of 110 ° C., a cylinder temperature of 270 ° C., a nozzle temperature of 260 ° C., a hot runner temperature of 2 using an injection molding machine of product number IS450 manufactured by Toshiba Machine Co.
50 ° C., injection speed 5.6 × 10 ⁻³ m ³ / s, injection pressure 1,000 kgf / cm ² , holding pressure 800 kgf / cm
^{2. The} mold clamping pressure was 1200 kgf / cm ² .

As shown in FIG. 2, the obtained light guide plate 10 has a thickness t1 of a thick portion 10a of 2.3 mm, a thickness t2 of a thin portion 10b on the opposite side of 0.6 mm, and a thickness t1 from the side of the thick portion 10a. The length t3 (length from the light source in the longitudinal direction of the light guide plate) toward the thin portion 10b is 190 mm, the length t4 along the axial direction of the linear light source is 280 mm, and the thin portion 10b extends from the thick portion 10a. It was wedge-shaped so that the thickness gradually decreased as it moved away from the side (in the direction substantially perpendicular to the axis of the linear light source). Further, on the light exit surface 10c and the light reflection surface 10d side of the light guide plate 10, a crimp pattern 30 whose arrangement density becomes gradually denser as the distance from the light source 20 side increases, was formed well without transfer failure. The grain pattern 30 had an average diameter d1 of 70 μm, a circular convex shape, an average height h1 of 15 μm, and a processing area occupancy of 35%. Table 1 shows the evaluation results of the moldability of the light guide plate 10.
Shown in

Example 2 In the same manner as in Example 1, wedge-shaped light guide plates having different grain patterns were obtained. The shape of the grain pattern 30 is
Average diameter d1 is 70 μm, shape is circular convex, average height h
1 was 15 μm, and the occupation ratio of the processing area was 55%. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Example 3 In the same manner as in Example 1, wedge-shaped light guide plates having different grain patterns were obtained. The shape of the grain pattern 30 is
Average diameter d1 is 50 μm, shape is circular convex, average height h
1 was 13 μm, and the occupation ratio of the processing area was 35%. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Example 4 A light guide plate 10 having a similar grain pattern was obtained in the same manner as in Example 1 except that the pellets of Production Example 2 were used. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Example 5 A light guide plate 10 having a similar grain pattern was obtained in the same manner as in Example 1 except that the pellets of Production Example 3 were used. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Example 6 A light guide plate 10 having a similar grain pattern was obtained in the same manner as in Example 1 except that the pellets of Production Example 4 were used. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Example 7 Using the pellets of Production Example 3, the hot runner temperature was set to 12
A light guide plate 10 having a similar grain pattern was obtained in the same manner as in Example 1 except that the temperature was set to 0 ° C. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Comparative Example 1 A light guide plate having a similar grain pattern 30 was produced in the same manner as in Example 1 except that the pellets of Production Example 3 were used and a mold having no hot runner and no hot nozzle was used. 10 was obtained. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

Comparative Example 2 A light guide plate 10 having the same grain pattern 30 was obtained in the same manner as in Comparative Example 1 except that the cylinder temperature of the injection device was set at 350 ° C. Table 1 shows the evaluation results of the moldability of the light guide plate 10.

[0086]

[Table 1]

As described above, according to the embodiment, when the hot runner type mold of the present invention is used, transferability and transparency of a grain pattern are excellent, and appearance defects such as sink marks, foaming and burning are not caused. Compared to the fact that the light guide plate can be molded, the light guide plate of the comparative example molded without using a hot runner mold has poor transferability of the grain pattern, and has poor appearance such as sink marks, foaming and burning. Can be confirmed. Comparative Example 2 in which the transferability of the grain pattern was improved by increasing the cylinder temperature without using a hot runner.
In the above, it was also confirmed that the transparency of the light guide plate was reduced due to thermal degradation of the resin.

[0088]

As described above, according to the present invention, when a large and thin molded article for an optical component having a fine shape on the surface is molded, it is excellent in transparency and transferability of the fine shape. Also provided is a method capable of molding a molded article free from appearance defects such as sink marks, foaming, and burning.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view showing a state in which a hot runner type mold device according to an embodiment of the present invention is clamped and a cylinder tip portion of an injection molding device;
(B) is a schematic partial sectional view of a hot runner portion.

2 (A) is a schematic plan view showing a light guide plate obtained by injection molding using the hot runner type mold apparatus of FIG. 1, and FIG. 2 (B) is a schematic view of FIG. 2 (A). Sectional view, FIG. 2 (C)
FIG. 4 is a partially enlarged view of a grain pattern formed on the light reflecting surface of the light guide plate of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Die apparatus and injection apparatus cylinder tip part 2 ... Injection apparatus cylinder tip part 21 ... Nozzle 3 ... Mold apparatus 4 ... Fixed board 5 ... Fixed side mold 51, 51 '... Second heater 52, 52' ... No. 2 runners 53, 53 'hot nozzle (hot tip) 6 movable plate 7 movable mold 71 cavity 72 third runner 73 gate 8 parting surface 9 manifold block 91 concave portion 92 first Runner 93 Hot runner 10 Light guide plate 10a Thick portion 10b Thin portion 10c Light emitting surface 10d Light reflecting surface 20 Light source 30 Grain pattern

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Issei Ishimaru 1-2-1, Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Within the Zeon Corporation General Development Center (72) Inventor Kazuyuki Obuchi Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa 1-2-1 1-1 Nippon Zeon Co., Ltd. General Development Center (72) Inventor Tatsuo Miyazaki 1-2-1, Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term in Nippon Zeon Co., Ltd. General Development Center 4F202 AA12 AA12C AH74 AH76 AM34 CA11 CB01 CK03 CK11 4J002 AC032 AC082 BB032 BB122 BB172 BC032 BC042 BC072 BC102 BD042 BD102 BD142 BD152 BE022 BG062 BN152 BP012 CB002 CE001 CF062 CF072 CF082 CF162 CG002 CH074 CL012 CL03 CM032

Claims (5)

[Claims] 1. A method for molding a molded article for an optical component, comprising a step of injection molding a resin composition containing an alicyclic structure-containing polymer using a hot runner type mold. 2. The molding method according to claim 1, wherein the mold has an uneven shape in the cavity. 3. The molding method according to claim 1, wherein the molded article for an optical component is a light guide plate. 4. The molding method according to claim 1, wherein the alicyclic structure-containing polymer is a norbornene-based ring-opened polymer or a hydride thereof. 5. An alicyclic structure-containing polymer according to JIS-K67.
19 at a temperature of 280 ° C. under a load of 2.16 kgf. The molding method according to any one of claims 1 to 4, having a melt flow rate of: