JP2001239556A - Method for molding thermoplastic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of molding a molded object excellent in surface accuracy by more precisely transferring a complicated shape and a fine shape, and the molded object molded by using the method. SOLUTION: A molten thermoplastic resin is molded by using a mold wherein a heat insulating layer is provided at least at a part of the mold wall surface constituting a cavity and the center line average roughness (Ra) of the mirror surface part of the uppermost surface of the cavity is 0.1 μm or less and the maximum height (Rmax) thereof is 1.0 μm or less.

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 thermoplastic resin suitable for molding an optical molded article or a substrate for an information recording medium, and a molded article molded by using the molding method.

[0002]

2. Description of the Related Art As a molded article used for an optical component such as an optical lens or an optical disk, a molded article obtained by injection molding a transparent thermoplastic resin such as an acrylic resin (PMMA) or a polycarbonate resin (PC) is used. In recent years, transparency,
Norbornene-based polymers and hydrogenated polystyrene resins, which are excellent in heat resistance and low water absorption, have also been proposed as materials for optical molded articles.

Recently, for such optical parts, for example, in an optical lens, a molded article having a more complicated shape such as the use of an aspherical lens has been required due to the reduction in the number of parts used for the purpose of weight reduction and the like. And optical discs
For the purpose of increasing the capacity, a device having higher density grooves (grooves) is required. In addition, liquid crystal display devices (LC
With the spread of D), a light guide plate made of a transparent resin used for an LCD backlight and the like are also required to be larger, thinner and have a fine shape.

[0004]

In such a situation, a method capable of transferring a complicated shape or a fine shape as described above more precisely and forming a formed body having excellent surface accuracy and a method of forming the formed body by using the method. It is an object of the present invention to provide a molded article, and it is a further object of the present invention to maintain such precise transferability, and surface accuracy, even if the part is larger and thinner. .

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, when molding a molded product, the cavity has a heat insulating layer in the cavity and the mirror surface of the outermost surface of the cavity has By using a mold having excellent surface accuracy, it has been found that a molded article having excellent transferability and surface accuracy can be provided.In addition, the above-mentioned heat-insulating mold having excellent surface accuracy of the mirror surface portion on the outermost surface of the cavity originally has a mirror surface portion. The present invention has been found to be obtained by forming a heat insulating layer by a specific method on a mold cavity surface having excellent surface accuracy.

Thus, according to the present invention, a heat insulating layer is provided on at least a part of the mold wall surface constituting the cavity, and the center line average roughness (Ra) of the mirror surface portion on the outermost surface of the cavity is 0.1 μm or less; A method for melt-molding a thermoplastic resin using a mold having a maximum height (Rmax) of 1.0 μm or less is provided. Further, according to the present invention, Ra formed by the above method has a Ra of 0.1 μm or less and a Rmax of 1.0 μm.
Provided is an optical molded product having a size of not more than μm. Further, according to the present invention, a heat insulating layer is provided on at least a part of the mold wall surface forming the cavity, and the center line average roughness (Ra) of the mirror portion on the outermost surface of the cavity is 0.1 μm.
Hereinafter, a mold having a maximum height (Rmax) of 1.0 μm or less is provided.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below by dividing them into items.

According to the molding method of the present invention, a heat insulating layer is provided on at least a part of a mold wall surface constituting a cavity of a mold, and a surface accuracy of a mirror portion on the outermost surface of the cavity is determined by a center line average roughness (Ra). 0.1 μm or less, maximum height (Rm
(a) a thermoplastic resin is melt-molded using a mold having a diameter of 1.0 μm or less.

[0009] heat insulating layer the heat insulating layer is characterized in that it is formed in a state of covering at least a portion of the mold wall surface which constitutes the mold cavity. As a material of the heat insulating layer, the thermal conductivity is low,
A material having excellent heat resistance and film strength (elongation, tensile strength, etc.) and having a coefficient of linear expansion close to that of a mold is usually used, and generally includes ceramic, resin or a resin composition. A resin or a resin composition is preferred because a film can be formed in a short time and by a simple method.

Examples of the resin include a polyamide resin, a polyimide resin, a polyamideimide resin, and a polyetherimide resin. As the resin composition, an inorganic filler such as glass, silica, and talc is used as the resin composition. And the like, heat resistance, linear expansion coefficient,
From the viewpoint of film strength and the like, a polyimide resin and a polyetherimide resin are preferable, and a polyimide resin is more preferable. Further, among the polyimide resins, a straight-chain high-molecular-weight polyimide is most preferable.

As a method of forming a heat insulating layer using a polyimide resin, (1) a method of applying a resin raw material solution on a cavity surface, performing soft baking and then imidizing by heating,
(2) A vapor deposition polymerization method for forming a polyimide polymer film in a vacuum is mentioned, but the ease of film formation, the uniformity of the film,
From the viewpoints of film strength (including interlayer adhesion) and surface accuracy of the film, the latter vapor deposition polymerization method is preferable.

A method for forming a polyimide heat-insulating layer on the surface of a mold cavity by vapor deposition polymerization includes, for example, ULVA.
C TECHNICAL JORNAL No. 50
The technique described in 1999 (p49-p52) can be used. Specifically, pyromellitic anhydride (PMDA) and oxydianiline (ODA), which are two kinds of raw material monomers, were respectively added at 200 to 240 ° C. and 18 ° C.
After preheating at 0 to 200 ° C. and feeding and evaporating into a vacuum layer heated to 160 to 230 ° C., the polyamic acid is vapor-deposited and polymerized on a mold cavity surface provided in the layer. PAA), followed by dehydration heating to form a polyimide film.

The thickness of the heat insulating layer is usually 0.1 to 500 μm.
m, preferably 0.2 to 200 μm, more preferably 0.5 to 100 μm. When the film thickness is in the above range, the film strength and the heat insulating effect are excellent, and the surface accuracy of the obtained molded body is improved. The preferred thickness range of all the heat insulating layers that can be used in the present invention is the same as above.

In the present invention, chemical etching, Ni plating,
A treatment such as Cr plating can be performed, and the thickness is usually 0.1 to 200 μm, preferably 0.2 to 100 μm.
m, more preferably 0.5 to 50 μm. After forming the plating layer, fine irregularities having a depth of submicron to several tens of microns can be formed on the plating layer.

In the present invention, the surface accuracy of the outermost surface of the mold cavity is 0.1 μm or less, preferably 0.05 μm or less, more preferably 0.1 μm or less in terms of center line average roughness (Ra).
01 μm or less, the maximum height (Rmax) is 1.0 μm or less, preferably 0.5 μm or less, more preferably 0.1 μm or less.
The respective molds are used below μm. With this mold, the transferability of the molded body can be improved, and the surface accuracy of the mirror portion can be improved. In the present invention, in order to keep the surface accuracy of the cavity outermost surface within the above range, the surface accuracy of the mirror surface portion of the mold cavity surface before forming the heat insulating layer is determined in advance, It is preferable to keep the same level as the accuracy. That is, the surface accuracy of the mirror surface portion of the mold cavity surface before the formation of the heat insulating layer is defined as the center line average roughness (Ra) of 0.1.
The maximum height (Rmax) is 1 μm or less, preferably 0.05 μm or less, more preferably 0.01 μm or less.
The thickness is set to 0 μm or less, preferably 0.5 μm or less, and more preferably 0.1 μm or less.

Thermoplastic Resin In the present invention, the thermoplastic resin used as a material for forming a molded article using the above-mentioned mold is not particularly limited, and is generally used industrially as a thermoplastic material. Any of these can be used, such as polycarbonate (PC) and polyethylene terephthalate (PE).
T), polyester resins such as polybutylene terephthalate (PBT) and liquid crystal polyester; acrylonitrile styrene resins such as acrylonitrile-butadiene-styrene (ABS) and acrylonitrile-styrene (AS); polyethylene, polypropylene, polymethyl-1 Polyolefin resins such as pentene (TPX) and polystyrene; acrylic resins such as polymethyl methacrylate; polyphenylene ether (PPE);
Aromatic condensation resins such as polyether sulfide (PPS) and polyarylate (PAR); norbornene resins, cyclic conjugated diene resins, monocyclic olefin resins, hydrogenated polystyrene resins, vinylated cyclic hydrocarbon resins, etc. Alicyclic structure-containing polymer resin; among which are excellent in transferability and surface precision, and suitable for molding optical molded articles and information recording medium substrates include polyester resins, acrylic resins, and the like. Preferred are alicyclic structure-containing polymer resins, among which PC, PMMA and alicyclic structure-containing polymer resins are more preferred, and alicyclic structure-containing polymer resins are most preferred.

The alicyclic structure-containing polymer resin The alicyclic structure-containing polymer has an alicyclic structure in the main chain and / or the side chain, and has a high alicyclic structure in the main chain from the viewpoint of mechanical strength and heat resistance. Those containing an alicyclic structure are preferred.

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 and heat resistance. The number of carbon atoms that make up the alicyclic structure is
From the viewpoints of heat resistance and moldability, the number is usually 4 to 30, preferably 5 to 20, and more preferably 5 to 15. The proportion of the repeating unit having an alicyclic structure is appropriately selected depending on the purpose of use, and is usually 50% by weight or more.
Preferably 70% by weight or more, more preferably 90% by weight
That is all. It is preferable from the viewpoint of transparency and heat resistance that the proportion of the repeating unit having an alicyclic structure be within this range.

Specific examples of such an alicyclic structure-containing polymer include (1) a norbornene-based polymer, (2) a monocyclic olefin-based polymer, (3) a cyclic conjugated diene-based polymer, and (4) ) Vinyl alicyclic hydrocarbon-based polymers and hydrogenated products thereof. Among these,
A norbornene-based polymer, a cyclic conjugated diene-based polymer and a hydrogenated product thereof are preferable, and a norbornene-based polymer is more preferable in terms of heat resistance and mechanical strength.

(1) Norbornene-based polymer The norbornene-based polymer is disclosed in, for example, JP-A-3-1488.
No. 2, JP-A-3-122137, and the like. Specifically, the polymer is a ring-opened polymer of a norbornene-based monomer, a hydrogenated product thereof, and an addition weight of a norbornene-based monomer. And an addition copolymer of a norbornene-based monomer and a vinyl compound.

Specific examples of the norbornene-based monomer used in the polymerization include 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-
En,

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-ethoxycarbonyl-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-methylpropionate, bicyclo [2,2,1] -hept-5-enyl-2-methyloctanoate, 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 (common name is dicyclope
Antadiene), tricyclo [4,3,1^2,5, 0
^1,6] -Dec-3-ene, tricyclo [4,4,1
^2,5, 0^1,6] -Undeca-3,7-diene
Is tricyclo [4,4,1^2,5, 0^1,6]-Unde
C-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, 9a-tetrahydrofluorene),
Tetracyclo [8,4,1^11,14, 0^1,10, 0
^3,8] -Tetradeca-3,5,7,12-11-tet
Raen (1,4-methano-1,4,4a, 5,10,1
0a-hexahydroanthracene)
A norbornene monomer having no bornan ring;

Tetracyclo [4,4,1^2,5, 1
^7,10, 0] -dodec-3-ene (simply tetracyclo
Dodecene), 8-methyl-tetracyclo [4,
4,1^{2 , 5}, 1^7,10, 0] -dodec-3-ene,
8-methyl-tetracyclo [4,4,1^2,5, 1
^7,10, 0] -Dodeca-3-ene, 8-ethyl-tet
Lacyclo [4,4,1^2,5, 1^7,10, 0] -dode
Car-3-ene, 8-methylidene-tetracyclo [4,
4,1^2,5, 1^7,10, 0] -dodec-3-ene,
8-ethylidene-tetracyclo [4,4,1^2,5, 1
^7,10, 0] -Dodeca-3-ene, 8-vinyl-tet
Lacyclo [4,4,1^2,5, 1^7,10, 0] -dode
Car-3-ene, 8-propenyl-tetracyclo [4,
4,1^2,5, 1^{7, 10}, 0] -dodec-3-ene,
8-methoxycarbonyl-tetracyclo [4,4,1
^2,5, 1^7,10, 0] -dodec-3-ene, 8-me
Tyl-8-methoxycarbonyl-tetracyclo [4,
4,1^2,5, 1^7,10, 0] -dodec-3-ene,
8-hydroxymethyl-tetracyclo [4,4,1
^2,5, 1^{7,1 0}, 0] -dodeca-3-ene, 8-ca
Ruboxy-tetracyclo [4,4,1^{2, 5}, 1
^7,10, 0] -Dodeca-3-ene, 8-cyclopentene
Le-tetracyclo [4,4,1^2,5, 1^7,10,
0] -dodec-3-ene, 8-cyclohexyl-tetra
Cyclo [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^{7,1 0}, 0] -dodeka-3-ene, pen
Tacyclo [6,5,1^1,8, 1^3,6, 0 ^2,7, 0
^9,13] -Pentadeca-3,10-diene, pentacyclo
Black [7,4,1^3,6, 1^10,13, 0^1,9, 0
^2,7] -Pentadeca-4,11-diene and other norbo
Norbornene-based monomers having a lunan ring are respectively
No.

The above norbornene monomers can be used alone or in combination of two or more.

In the present invention, in addition to the norbornene-based monomers, 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-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1- Octene, 1-decene, 1-dodecene, 1-
Tetradecene, 1-hexadecene, 1-octadecene,
Α-olefins having 2 to 20 carbon atoms such as 1-eicosene; cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene; Cycloolefins such as 3a, 5,6,7a-tetrahydro-4,7-methano-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 can be used. These copolymerizable monomers can be used alone or in combination of two or more.

The ring-opening polymer of the above-mentioned monomer is a catalyst system comprising, as a ring-opening polymerization catalyst, a halide, nitrate or acetylacetone compound of a metal such as ruthenium, rhodium, palladium, osmium, iridium or platinum, and a reducing agent; Alternatively, titanium, vanadium, zirconium, tungsten, a metal halide such as molybdenum or an acetylacetone compound, using a catalyst system comprising an organoaluminum compound, in a solvent or without a solvent, usually at -50 ℃ ~ 100 ℃ Polymerization temperature, 0-50k
It can be obtained by ring-opening polymerization at a polymerization pressure of g / cm ² . The hydrogenated norbornene-based polymer can be obtained by adding hydrogen to a ring-opening (co) polymer in the presence of a hydrogenation catalyst according to a conventional method.

The addition copolymer of the norbornene-based monomer and the copolymerizable monomer is, for example, a monomer component comprising a titanium compound, a zirconium compound, or a vanadium compound and an organic aluminum compound in a solvent or without a solvent. In the presence of a catalyst system, usually -50 ° C to 1
It can be obtained by a method of copolymerizing at a polymerization temperature of 00 ° C. and a polymerization pressure of 0 to 50 kg / cm ² .

(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 configuration of these vinyl alicyclic hydrocarbon-based polymers may be any of atactic, isotactic and syndiotactic. For example, any of 0 to 100% in syndiotacticity by dyad display. Can also 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, but the gel permeation of a cyclohexane solution (a toluene solution when the polymer is not dissolved) is used. The weight average molecular weight in terms of polyisoprene measured by a chromatographic method is 5,0
00 to 500,000, preferably 8,000 to 20
0000, more preferably 10,000-100,0
When it is in the range of 00, the mechanical strength and the moldability are highly balanced and suitable. The glass transition temperature (Tg) of the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use, but is usually 50 to 300.
° C, preferably 60-200 ° C, more preferably 70-200 ° C.
180 ° C.

Ingredients The above thermoplastic resin may contain, if desired, an antioxidant such as a phenolic antioxidant or a phosphorus antioxidant, an ultraviolet absorber such as a benzophenone ultraviolet absorber, a light stabilizer,
Various compounding agents such as an antistatic agent, an ester of an aliphatic alcohol, a partial ester and a partial ether of a polyhydric alcohol may be blended. In addition, other resins, rubbery polymers and the like can be mixed and used as long as the object of the present invention is not impaired.

(Filler) In the present invention, an inorganic or organic filler can be blended with the thermoplastic resin in order to obtain a molded product requiring mechanical strength, dimensional stability and surface accuracy. . Examples of the filler include, for example, inorganic fine particles such as glass, talc, and calcium carbonate, and organic fine particles such as silicone; organic and inorganic fibers such as glass fiber and carbon fiber; and short fibers such as whiskers. In order to obtain a molded product having more excellent surface accuracy, the shape of the filler is preferably spherical (beads),
A true sphere is most preferred. The average particle diameter of the filler particles is usually 0.005 to 20 μm, preferably 0.0 to 20 μm.
It is 1 to 15 μm, more preferably 0.05 to 8 μm, and 0.01 to 5 μm, particularly preferably 0.05 to 5 μm for an application requiring extremely high surface accuracy, such as a substrate for a magnetic recording medium. The range is 1 μm. Further, those having a small particle size distribution are preferable, and are 1/5 to 2 times the average particle size.
The doubled range of particles accounts for 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more. As long as these conditions are satisfied, a plurality of types of fillers may be mixed and a plurality of peaks in the particle size distribution may be present. If the average particle size is too small, the fluidity of the molten resin at the time of molding decreases, and if it is too large, the surface roughness of the molded product increases. If the particle size distribution is too large, the surface roughness of a part of the molded article may increase even if the average particle size is small.

Molding Method and Molded Body Using the above-described thermoplastic resin and a mold having a heat insulating layer,
In order to obtain the molded article of the present invention, a method of molding by heating and melting a thermoplastic resin is used. Specific methods include an injection molding method, an injection compression molding method, a press molding method, an injection blow molding method, a direct blow molding method, and the like, which are suitable as optical molded articles and information recording medium substrates. In order to obtain a molded article, an injection molding method, an injection compression molding method, or the like is preferable.

(Molding conditions) The molding conditions of the above-mentioned hot melt molding method differ depending on the type of the thermoplastic resin used.
g, (Tg + 100 ° C.) to (Tg + 2
50 ° C.), preferably (Tg + 140 ° C.) to (Tg + 2
00 ° C.), more preferably (Tg + 160 ° C.) to (Tg
+ 180 ° C), the nozzle temperature is 200-300 ° C,
Preferably it is 250-280 degreeC. The injection pressure is 700 to 1500 (kg / cm) in the case of the injection molding method.
² ), preferably 1000 to 1400 (kgf / c
m ² ), and 400 to 120 in the case of the injection compression molding method.
0 (kg / cm ² ), preferably 500 to 1000 (k
gf / cm ² ). By setting the molding conditions within the above range, the transferability of the obtained molded body can be improved without lengthening the cooling time.

(Molded body) The molded body may be spherical, rod-shaped, cylindrical,
It can be formed into a disk shape, a plate shape, a sheet shape, a shape obtained by combining them, and the like. When the method of the present invention is used, the surface accuracy is such that Ra is 0.1 μm or less, preferably 0.05 μm or less. , More preferably 0.01 μm or less, and Rmax of 1.0 μm or less, preferably 0.1 μm or less.
It is 5 μm or less, more preferably 0.1 μm or less. Further, particularly, the surface accuracy is 0.02 μm or less in Ra, Rm
When ax is 0.2 μm or less, the molded body is suitable as a substrate for a magnetic recording medium.

Further, when the molding method of the present invention is used, a molded article excellent in transferability and surface accuracy can be molded even if it is a large and thin molded article, and especially a molded article having a thickness of 2 m.
The effect of the present invention becomes more remarkable when a molded body having a maximum length of m or less is 100 mm or more, preferably 150 mm or more, more preferably 200 mm or more.

Further, when the method of the present invention is used, even if the surface of the molded article has fine irregularities, the shape of the irregularities can be transferred precisely. The fine concavo-convex shape means a fine concavo-convex shape in which the depth and width of a concave portion and the height and width of a convex portion are in units of sub-microns to several millimeters. Even if the ridges and valleys formed by the method have uneven shapes having relatively acute angles in the pit-shaped recesses, the method of the present invention can precisely transfer. As a specific example of the concave-convex shape, when the concave-convex shape unit is regularly arranged to form a fine concave-convex shape, the constituent units are prismatic, cubic, rectangular, cylindrical, elliptical, spherical. Or a shape such as an aspherical shape, more specifically, for example, a prism shape, a condensing lens shape, a groove shape, a stippled shape, and the like, preferably a fine prism, a fine lens shape, Preferably, the shape is a fine grain prism or fine lens in submicron units. Further, according to the method of the present invention, irregularities such as a textured surface having an intentionally roughened surface, for example, a textured surface having a surface roughness Ra of 10 μm or more can be precisely transferred, and the textured surface of the obtained molded article can be precisely transferred. The Ra of the processed surface is also substantially equal to the value of the mold, but when the method of the present invention is not used, the textured surface of the obtained molded product has irregularities crushed and Ra is smaller than the value of the die. Value.

As described above, the molded article obtained by the method of the present invention is excellent not only in the transferability and surface accuracy of the fine irregularities, but also in the low birefringence, the solvent crack resistance and the like.

The molded article of the present invention obtained by the use or method is particularly suitable as an optical molded article such as a substrate for optical lenses and the information recording medium, specifically, a camera viewfinder lens, a camera Optical lenses such as imaging system lenses, Fθ lenses for laser beam printers, optical pickup lenses, collimator lenses, cylindrical lenses, prism lenses; Fθ mirrors, polygon mirrors,
Optical components such as bar coder mirrors and car interior mirrors; can be used as substrates for information recording media such as compact disk substrates, magneto-optical disk substrates, phase-change optical disk substrates, mini disk substrates, and digital video disk substrates, especially on the surface A molded body having excellent precision is suitable as a substrate for a magnetic recording medium such as a plastic hard disk substrate as described above. In addition to the above-mentioned mirror, a molded article molded using a thermoplastic resin mixed with the above-mentioned filler, a reflector for a lamp, a liquid crystal display element (L
It can be used as a light diffusing plate for CD), among which it is particularly suitable for an extension reflector for automotive lighting, a light diffusing plate, and the like.

Further, the above molded product is suitable for a large and thin molded product such as a light guide plate for an LCD backlight.

[0043]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples, but the scope of the present invention is not limited to these examples. In these examples, [parts] are based on weight unless otherwise specified. The methods for measuring various physical properties are as follows.

(1) Tg is measured by a differential scanning calorimeter (DSC).
Method). (2) Unless otherwise specified, the molecular weight was measured as a polyisoprene conversion value measured by gel permeation chromatography (GPC) using cyclohexane as a solvent. (3) The cavity surface of the mold and the surface accuracy of the molded body are:
Using a contact type surface roughness meter manufactured by Taylor Hobson,
a and Rmax were measured and evaluated. (4) The thickness of the heat insulating layer was determined by photographing a cross section of the film on the mold with a stereoscopic microscope. (5) The transferability of the molded body was determined by molding a molded body having a plurality of angular grooves and evaluating the transferability of the grooves of the molded body by the following method. Whether or not the corners of the groove of the obtained molded body are retained was evaluated by observing the groove with a microscope or the like. (If the groove can be visually observed with an optical microscope, by this method, if it cannot be visually observed, Observed by an atomic force microscope (AFM) or the like.) Measure the depth of the deepest part of the groove, compare it with the height of the corresponding convex part of the mold, and measure (depth of groove / height of the corresponding part of the mold) x 100 as the transfer rate (%) Was evaluated.
According to the above-described method, the corner portion of the groove is retained and the transfer rate of the groove is 90% or more [A rank]. In some places, the corner portion is lost, but the transfer rate is 90% or more. In [B rank], there are some places where the corners are missing, and when the transfer rate is less than 70 to 90%, [C rank], there are many places where the corners are missing. Those having a ratio of less than 70% were designated as [D rank]. In addition, as a molded body having the above-mentioned groove, V of several tens μm in both width and depth is used.
A light guide plate having a U-shaped groove and an optical disk having a concave groove having a width of 1 μm and a depth of 1 μm were formed, and the above evaluation was carried out irrespective of the shape and size (width and depth) of the groove.

[Production Example 1] Production of molding material (polymer resin containing alicyclic structure) Under a nitrogen atmosphere, 8-ethyltetracyclo [4.4.0.
^12,5 . 1 ^7,10 ] -dodec-3-ene (hereinafter referred to as E
TD) 15 parts, tricyclo [4.3.0.1
^2,5 ] deca-3,7-diene (dicyclopentadiene; hereinafter, referred to as DCP) (85 parts) is dissolved in dehydrated cyclohexane (250 parts), and 1-hexene (1.8 part) is added as a molecular weight modifier to give a known compound. Polymerized with a metathesis ring-opening polymerization catalyst, and then hydrogenated by a known method to give ETD / D
A hydrogenated CP ring-opening copolymer was obtained. When the copolymerization ratio of each norbornene in the polymer was calculated from the composition of the residual norbornene in the solution after polymerization (by gas chromatography), it was almost equal to the charged composition at ETD / DCP = 15/85. The weight-average molecular weight (Mw) of the hydrogenated product of the ETD / DCP ring-opening polymer is 31,00.
0, the hydrogenation rate was 99.9%, and the Tg was 103 ° C.

An antioxidant (Ilganox 10 manufactured by Ciba Geigy) was added to 100 parts of the hydrogenated ring-opening polymer obtained.
10) 0.2 parts and 0.2 parts of a soft polymer (ToughTech H1052 manufactured by Asahi Kasei Corporation) were added, and a twin-screw kneader (TEM-35B manufactured by Toshiba Machine Co., screw diameter 37 mm, L / D =
32, screw rotation speed 250 rpm, resin temperature 210
At a feed rate of 10 kg / hour) and extruded into pellets.

[Example 1] (Example of manufacturing a mold having a heat insulating layer) Length 280 mm, width 1
A V-shaped ridge line (height 70-70 mm) is formed on the entire bottom surface of the mold cavity surface for the wedge-shaped light guide plate such that the thickness gradually decreases from 2.5 mm to 1.5 mm in the length direction.
A plurality of stampers having a thickness of 80 μm and an angle of 110 ° were attached. The V-shaped ridge on the stamper is
It is formed so as to be parallel to the width direction and gradually increase in the interval in the length direction from sparse to dense. A polyimide heat-insulating film having an average film thickness of 50 μm was formed on both the V-shaped ridge line portion and the mirror surface portion of the stamper surface by a vacuum deposition polymerization method. A 10 μm-thick Cr layer was formed as a protective layer on the polyimide heat-insulating film by a chemical vapor deposition method (CVD).
Method). As a result of measuring the surface accuracy on the protective layer, Ra = 0.01 μm and Rmax = 0.1 μm.

(Formation of Light Guide Plate)
After preheating drying at 80 ° C. for 2 hours, injection molding is performed using an injection molding apparatus having a hot runner and a side gate mold system (product number IS450 manufactured by Toshiba Machine Co., Ltd.). A 4-inch light guide plate was formed. Molding conditions are: mold temperature 80 ° C, cylinder temperature 26
0 ° C., nozzle temperature 250 ° C., hot nozzle (hot chip) temperature 250 ° C., hot runner temperature 250 ° C. The obtained light guide plate has a width of 190 mm and a length of 280 m.
m, a wedge-like shape whose thickness gradually decreases along the length direction, the thickness of the thick portion was 2.5 mm, and the thickness of the thin portion on the opposite side was 1.5 mm.

A V-shaped groove was formed in the obtained light guide plate so as to be parallel to the width direction and to gradually increase in density from sparse to dense in the length direction. By the method described above,
As a result of evaluating the transferability of the groove, the transferability was good.
Further, as a result of evaluating the surface accuracy of the mirror surface portion where the groove is not formed by the above-described method, the surface accuracy was the same level as the surface accuracy of the mirror surface portion of the mold, and the accuracy of the mold was accurately reproduced. The results are shown in Table 1.

[0050]

[Table 1]

[Example 2] As a resin for the molding material, PMMA (manufactured by Sumitomo Chemical Co., Ltd .: Part No. MG5) was used instead of the alicyclic structure-containing polymer resin, and the molding conditions were set at a mold temperature of 80 ° C and a cylinder temperature of 260. C., a nozzle temperature of 250 ° C., a hot nozzle (hot chip) temperature of 250 ° C., and a hot runner temperature of 250 ° C., except that the light guide plate was molded and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Embodiment 3] Instead of a light guide plate, 120 mm
An optical disk substrate was molded using a mold capable of molding an optical disk substrate having a groove having a diameter of 0.6 mm, a groove having a width of 1 μm and a depth of 1 μm, and the same evaluation as in Example 1 was performed. . The results are shown in Table 1.

Example 4 Instead of a light guide plate, a magnetic recording medium substrate was formed using a mold capable of forming a magnetic recording medium substrate (plastic hard disk) having a diameter of 3.5 inches and a thickness of 1 mm. Evaluation was performed in the same manner as in Example 1. The surface accuracy of the mold used was Ra = 0.005 μm, Rmax =
Although the thickness was set to 0.05 μm, the surface accuracy of the obtained substrate was also at the same level, and the surface accuracy of the mold was accurately reproduced. The results are shown in Table 1.

Example 5 100 parts of the alicyclic structure-containing polymer resin pellet obtained in Production Example 1 and 20 parts of glass fiber (length: 1.5 to 10 mm, diameter: about 1 μm) were blended. The mixture was melt-kneaded using a shaft kneader (cylinder temperature: 210 ° C.), and pelletized again. Using the obtained glass fiber-containing resin composition pellets, an extension reflector for automobile lighting was molded using a mold capable of molding an extension reflector for automobile lighting, and evaluation was performed in the same manner as in Example 1. The surface accuracy of the mirror surface of the obtained molded body was Ra = 0.02 μm and Rmax = 0.3 μm, which were almost the same level as the surface accuracy of the mold. The results are shown in Table 1.

Example 6 100 parts of the alicyclic structure-containing polymer resin pellets obtained in Production Example 1 were mixed with 10 parts of silicone beads (manufactured by GE Toshiba, part number Tospearl 145), and a twin-screw kneader was used. And melt kneading (cylinder temperature 2
10 ° C.) and pelletized again. Using the silicone bead-containing resin composition pellets obtained above, 210 mm
A light diffusing plate was molded using a mold capable of molding a light diffusing plate having a size of 340 mm and a thickness of 2 mm, and evaluation was performed in the same manner as in Example 1. The surface accuracy of the mirror surface of the obtained molded body was Ra = 0.0
3 μm and Rmax = 0.2 μm, which were almost the same level as the mold surface accuracy. The results are shown in Table 1.

Example 7 A light guide plate was formed in the same manner as in Example 1 except that a mold having a polyimide heat-insulating film formed by a solution coating method was used instead of the vacuum deposition polymerization method. The surface accuracy on the protective film was the same as in Example 1 (Ra
= 0.01 μm, and Rmax = 0.1 μm). As a result, the film thickness of the heat insulating film was 10 μm. As a result, a sufficient heat insulating effect was not obtained due to the small film thickness, and the transferability was slightly reduced. The results are shown in Table 1.

[Comparative Example 1] Without a heat insulating film, the surface accuracy of the cavity surface was Ra = 0.01 µm, and Rmax =
A light guide plate was molded in the same manner as in Example 1 except that a mold having a thickness of 0.1 μm was used. As a result, transferability was reduced.
The results are shown in Table 1.

[Comparative Example 2] Without a heat insulating film, the surface accuracy of the cavity surface was Ra = 0.01 µm, and Rmax =
A light guide plate was molded in the same manner as in Example 1 except that a mold having a thickness of 0.1 μm was used and PMMA was used as a resin. As a result, transferability was reduced as in Comparative Example 1. Table 1 shows the results
It describes in.

[Comparative Example 3] No heat insulation coating was provided, and the surface accuracy of the cavity surface was Ra = 0.005 μm, Rmax =
An optical disc substrate was molded in the same manner as in Example 3 except that a mold having a thickness of 0.05 μm was used.
As in 1, transferability was reduced. . The results are shown in Table 1.

[Comparative Example 4] Without a heat insulating film, the surface accuracy of the cavity surface was Ra = 0.01 µm, and Rmax =
An extension reflector for automotive lighting was molded in the same manner as in Example 5 except that a mold having a diameter of 0.1 μm was used. As a result, the surface accuracy of the molded body was reduced. The results are shown in Table 1.

Comparative Example 5 A light guide plate was formed in the same manner as in Example 7 except that a mold having a 50-μm polyimide heat-insulating film formed by applying the solution five times was used by a solution coating method. The surface accuracy on the protective film is Ra = 0.13μ.
m, Rmax = 1.3 μm. The transferability and surface accuracy of the obtained light guide plate were reduced. The results are shown in Table 1.

[0062]

According to the present invention, it is possible to obtain a molded article having more excellent transferability while maintaining the surface accuracy of the mold.

Claims (10)

[Claims] 1. A heat insulating layer is provided on at least a part of a mold wall surface constituting a cavity, a center line average roughness (Ra) of a mirror surface portion on the outermost surface of the cavity is 0.1 μm or less, and a maximum height (Rmax). Melt molding a thermoplastic resin using a mold having a diameter of 1.0 μm or less. 2. The heat insulation layer is formed on a mold cavity wall surface having a center line average roughness (Ra) of a mirror surface portion of 0.1 μm or less and a maximum height (Rmax) of 1.0 μm or less. The method of claim 1, wherein: 3. The method according to claim 1, wherein the heat insulating layer is made of a resin or a composition thereof. 4. The resin according to claim 3, wherein the resin is a polyimide resin.
The described method. 5. The method according to claim 1, wherein the heat insulating layer is formed by vapor deposition polymerization. 6. The method according to claim 1, wherein the thermoplastic resin is an alicyclic structure-containing polymer resin. 7. Molded by the method according to claim 1, wherein Ra is 0.1 μm or less and Rmax is 1.0.
A molded article for optical use, which is not more than μm. 8. The maximum length of a portion having a thickness of 2 mm or less is 100.
The molded article for optical use according to claim 7, which is not less than mm. 9. Molded by the method according to claim 1, wherein Ra is 0.02 μm or less and Rmax is 0.2.
A substrate for a magnetic recording medium, which is not more than μm. 10. A heat insulation layer is provided on at least a part of a mold wall surface constituting a cavity, a center line average roughness (Ra) of a mirror surface portion on the outermost surface of the cavity is 0.1 μm or less, and a maximum height (Rmax). Is 1.0 μm or less.