Manufacturing method of optical components

Abstract

To provide a method for manufacturing an optical component having excellent mold transferability.SOLUTION: There is provided a method for manufacturing an optical component, which uses an injection molding equipment. The injection molding equipment comprises: an injection unit; and a mold 10 having a cavity 16 including a molding region 16a and a gate 18, in which the mold 10 is composed of a first mold 12 and a second mold 14, the first mold 12 has a molding surface 12a, the second mold 12 comprises a protruding core 15 configured to be slidable in a first mold direction, and the protruding core 15 has a molding surface 15a. The method for manufacturing the optical component comprises: a process of moving the protruding core 15 in a direction opposite to the first mold direction and then widening a width between the first mold 12 and the second mold 14 to expand the molding region 16a; a process of injecting and inserting a molten resin containing a copolymer of ethylene or α-olefin and a cyclic olefin into the cavity 16 through the gate 18; and a process of applying a holding pressure to the molten resin from the injection unit side and pressurizing the molten resin by the protruding core 15 while pushing the protruding core 15 provided in the second mold 14 to the molding region 16a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an optical component. [Background technology]

[0002] Cyclic olefin copolymers have excellent optical properties and are therefore used, for example, as optical components such as optical lenses. Patent Document 1, for example, describes a technique relating to a method for producing an optical component made of a cyclic olefin copolymer.

[0003] Patent Document 1 describes a method for manufacturing a resin molded product, which includes a step of injecting molten resin into a mold from a nozzle at the tip of an injection unit, and a step of applying a predetermined compressive force to the resin in the mold by pressing a compression ejector pin into the mold while applying a dwell pressure to the resin in the mold from the injection unit side. This document describes that this method can produce a resin molded product that has low birefringence, excellent surface smoothness, and inconspicuous weld lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-112867 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the manufacturing method described in Patent Document 1, there was a large error in shape from the design values ​​of the molding die, and it was sometimes impossible to obtain a resin molded product in the desired shape.

[0006] Furthermore, in the manufacturing method described in Patent Document 1, surface roughness sometimes occurred on the optical surface of the obtained resin molded product. Note that surface roughness on the optical surface is a phenomenon in which the shape of the mold cannot be accurately transferred and irregularities occur on the surface of the optical surface of the resin molded product, and is different from the weld lines described in Patent Document 1, which are lines that appear when resins flowing inside a mold join together. Furthermore, in the manufacturing method described in Patent Document 1, there is room for improvement in that the average amount of birefringence in the vicinity of the gate of the obtained resin molded article is large. [Means for solving the problem]

[0007] As a result of their investigations, the inventors discovered that a method for manufacturing optical components using a specific injection molding apparatus can improve mold transferability and solve the above-mentioned problems, and thus completed the present invention. That is, the present invention can be shown as follows.

[0008] [1] A mold including an injection unit, a cavity including a molding area for molding an optical component having an optical surface, and a gate serving as an injection port for injecting molten resin from the injection unit into the cavity; The mold comprises a pair of a first mold and a second mold, and the width between the first mold and the second mold in the molding area of ​​the cavity formed between these molds is 2 mm or more and 15 mm or less, The first mold has an area of ​​310 mm for forming the optical surface. 2 More than 5030mm 2 The molding surface in the molding area is: The second mold has an ejection core configured to be slidable in the direction of the first mold within an opening, and the ejection core has an area of ​​310 mm2 for forming the optical surface. 2 More than 5030mm 2 A method for manufacturing an optical component using an injection molding apparatus having the following molding surfaces in the molding area, a step of moving the ejection core by 0.30 mm to 3 mm in a direction opposite to the first mold direction to increase a width between the first mold and the second mold in the molding region of the cavity, thereby expanding the molding region; Melting a resin composition containing ethylene or a copolymer of an α-olefin and a cyclic olefin; injecting the molten resin from the injection unit through the gate into the cavity; a step of injecting the molten resin into 80% or more of the inner volume of the molding region of the cavity, and injecting the molten resin into 100% of the inner volume of the molding region while pushing the ejection core of the second mold into the molding region, and then applying a holding pressure to the molten resin in the cavity from the injection unit side while pushing the molten resin with the ejection core; A method for manufacturing an optical component, comprising: [2] The method for manufacturing an optical component described in [1], wherein the gate is formed between the first mold and the second mold and is in communication with the cavity. [3] The method for producing an optical component according to [1] or [2], wherein the copolymer has a glass transition temperature of more than 120°C and not more than 170°C. [4] The copolymer, At least one olefin-derived repeating unit (a) represented by the following general formula (I); A repeating unit represented by the following general formula (II) and a repeating unit represented by the following general formula (III) and at least one repeating unit (b) derived from a cyclic olefin selected from the group consisting of repeating units represented by the following general formula (IV): The method for producing an optical component according to any one of [1] to [3], comprising: [ka] (In the above general formula (I), R 300 represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. [ka] (In the general formula (II), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, and R 61 ~R 78 And R a1 and R b1 may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring. [ka] In the general formula (III), x and d are 0 or an integer of 1 or more, and y and z are is 0, 1 or 2, and R 81 ~R 99 may be the same or different, and each is a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an alkoxy group; R 89 and R 90 and the carbon atom to which R is bonded. 93 or the carbon atom to which R is attached 91 may be bonded directly or via an alkylene group having 1 to 3 carbon atoms, and when y=z=0, R 95 and R 92 or R 95 and R 99 may be bonded to each other to form a monocyclic or polycyclic aromatic ring. [ka] (In the general formula (IV), R 100 , R 101may be the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and f is 1≦f≦18.)[5] The repeating unit (b) derived from the cyclic olefin in the copolymer (A1) is selected from the group consisting of bicyclo[2.2.1]-2-heptene and tetracyclo[4.4.0.1 2,5 .1 7,10 The method for producing an optical component according to [4], comprising repeating units derived from at least one compound selected from the group consisting of 1-, 2-dihydro-, 3-dodecene and 4-methyl-1-propanediol. [6] The method for producing an optical component according to [4] or [5], wherein the olefin-derived repeating unit (a) in the copolymer (A1) contains an ethylene-derived repeating unit. Effect of the Invention

[0009] According to the method for producing optical components of the present invention, due to its excellent mold transferability, it is possible to obtain optical components having a desired shape and in which surface roughness of the optical surface is suppressed, and further it is possible to obtain optical components having a small average amount of birefringence near the gate portion. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1(a) is a schematic cross-sectional view of an injection molding apparatus showing the position of an ejection core before injection molding of a copolymer, and FIG. 1(b) is a schematic cross-sectional view of an injection molding apparatus showing the position of the ejection core after injection molding of a copolymer. [Diagram 2] FIG. 2 is a schematic top view and a schematic cross-sectional view of an optical component (resin molded product) obtained by the manufacturing method of this embodiment. [Diagram 3] FIG. 3 is an optical microscope photograph of the surface (optically effective surface) of the lens obtained in Example 1. [Figure 4] FIG. 4 is an optical microscope photograph showing the surface roughness that occurred on the surface (optically effective surface) of the lens obtained in Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all drawings, similar components are given similar reference symbols and their description will be omitted as appropriate. In addition, "~" indicates "above" to "below" unless otherwise specified. First, an injection molding apparatus used in the method for manufacturing an optical component according to this embodiment will be described.

[0012] <Injection molding equipment> The injection molding apparatus of this embodiment includes an injection unit (not shown) and a mold 10, as shown in FIG.

[0013] The injection unit can be a conventional one, and is equipped with a hopper for feeding the resin, a cylinder for heating the resin, an injection nozzle, etc., and can inject the molten resin into the cavity 16 through the gate 18.

[0014] The mold 10 has a cavity 16 including in part a molding region 16a for molding an optical component having an optical surface, and a gate 18 which serves as an injection port for the molten resin from the injection unit into the cavity 16. The molding region 16a is an area sandwiched between a molding surface 12a of a first mold 12 and a molding surface 15a of an ejection core 15, which will be described later. The mold 10 is made up of a pair of a first mold 12 and a second mold 14 . A gate 18 is formed between the first mold 12 and the second mold 14 and communicates with the cavity 16 .

[0015] The molding region 16a is a region for molding a desired optical component, and the optical component has a cross-sectional shape of one side convex and one side concave, both sides convex, both sides concave, one side flat and one side concave, one side flat and one side convex, one side flat and one side flat, etc. The optical component may be circular, elliptical, etc. in a plan view.

[0016] The width a between the first mold 12 and the second mold 14 in the molding region 16a of the cavity 16 can be set to 2 mm or more and 15 mm or less, preferably 2.5 mm or more and 12 mm or less, and more preferably 2.5 mm or more and 10 mm or less. The width of the gate 18 (the width between the first mold 12 and the second mold 14) is about 30% or more and 100% or less of the width a of the molding region 16a.

[0017] The first mold 12 exposes a molding surface 12a for forming the optical surface of the optical component within the molding region 16a. The shape of the molding surface 12a is set to match the shape of the optical surface of the optical component, and may be a convex, concave, or planar shape in cross section, or may be a circular, elliptical, or other shape in plan view. The width of the molding surface 12a (diameter in the case of a circular shape) is indicated by b in FIG. 1.

[0018] The area of ​​the molding surface 12a is 310 mm 2 More than 5030mm 2 Less than 415mm, preferably 2 More than 2850mm 2 Less than 490mm, more preferably 2 More than 2000mm 2 When the molding surface 12a has a circular shape in a plan view, the diameter b can be set to 20 mm or more and 80 mm or less, preferably 23 mm or more and 60 mm or less, and more preferably 25 mm or more and 50 mm or less.

[0019] The second mold 14 includes an ejection core 15. The ejection core 15 is connected to a power means such as a hydraulic cylinder (not shown), and is configured to be able to slide within the opening of the second mold 14, and can move in the direction toward and in the opposite direction to the first mold 12, as shown in Figures 1(a) and 1(b).

[0020] The power means includes a control means for controlling the moving position of the ejection core 15, and is configured so as to be able to stop the ejection core 15 at a predetermined position. The ejection core 15 exposes a molding surface 15a in the molding region 16a for forming the optical surface of the optical component.

[0021] The shape of molding surface 15a is set to match the shape of the optical surface of the optical component, and may be a convex, concave, or planar shape in cross section, or may be a circle, ellipse, etc. in plan view. The width of molding surface 15a (diameter in the case of a circle) is indicated by c in FIG.

[0022] The area of ​​the molding surface 15a is 310 mm 2 More than 5030mm 2 Less than 415mm, preferably 2 More than 2850mm 2 Less than 490mm, more preferably 2 More than 2000mm 2 When molding surface 15a has a circular shape in a plan view, diameter c can be set to 20 mm or more and 80 mm or less, preferably 23 mm or more and 60 mm or less, and more preferably 25 mm or more and 50 mm or less.

[0023] <Manufacturing methods for optical components> The method for manufacturing an optical component according to this embodiment uses the above-mentioned injection molding apparatus and includes the following steps. Step a: The ejection core 15 is moved 0.30 mm to 3 mm in the direction opposite to the first mold direction 12 to increase the width between the first mold 12 and the second mold 14 in the molding area 16a of the cavity 16, thereby expanding the molding area 16a. Step b: A resin composition containing ethylene or a copolymer of an α-olefin and a cyclic olefin is melted. Step c: The molten resin obtained in step b is injected from the injection unit into the cavity 16 through the gate 18. Step d: Molten resin is injected into 80% or more of the inner volume of the molding area 16a of the cavity 16, and while pushing the ejection core 15 provided in the second mold into the molding area 16a, the molten resin is injected until the inner volume of the molding area 16a reaches 100%. Next, pressure is applied to the molten resin in the cavity 16 from the injection unit side, and the molten resin is pressed by the ejection core 15.

[0024] [Step a] In this process, the ejection core 15 is moved in the direction opposite to the first mold direction 12 by 0.30 mm to 3 mm, preferably 0.4 mm to 2 mm, and more preferably 0.5 mm to 1 mm, using a power means such as a hydraulic cylinder (not shown), to change from the state shown in Figure 1(b) to the state shown in Figure 1(a). This causes the molding region 16a to expand.

[0025] [Step b] In this step, a resin composition containing ethylene or a copolymer of an α-olefin and a cyclic olefin is introduced into a cylinder through a hopper, and the resin composition is heated and melted in the cylinder. The resin composition is then moved to an injection nozzle by rotating a screw in the cylinder. The order of steps a and b does not matter, and they may be carried out simultaneously.

[0026] The temperature of the molten resin composition (cylinder set temperature) can be appropriately determined depending on the glass transition temperature (Tg) and melting point (Tm) of the resin, but is usually "Tg+100° C." to "Tg+180° C.", preferably "Tg+120° C." to "Tg+170° C." The screw rotation speed is not particularly limited, but is usually appropriately selected in the range of 10 to 300 rpm. The resin composition in this embodiment will be described.

[0027] (Resin composition) The resin composition of the present embodiment contains a cyclic olefin copolymer (A) having a repeating unit derived from a cyclic olefin as an essential constituent unit. Examples of the cyclic olefin copolymer (A) include copolymers (A1) of ethylene or an α-olefin and a cyclic olefin.

[0028] The cyclic olefin compound constituting the copolymer (A1) in this embodiment is not particularly limited, and examples thereof include the cyclic olefin monomers described in paragraphs 0037 to 0063 of WO 2006 / 0118261.

[0029] From the viewpoints of further improving heat resistance and improving moldability while maintaining a good balance between the transparency and refractive index of the obtained optical component, the copolymer (A1) in this embodiment preferably has at least one olefin-derived repeating unit (a) represented by the following general formula (I) and at least one cyclic olefin-derived repeating unit (b) selected from the group consisting of repeating units represented by the following general formula (II), repeating units represented by the following general formula (III), and repeating units represented by the following general formula (IV).

[0030] [ka]

[0031] In the above general formula (I), R 300 represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.

[0032] [ka]

[0033] In the above general formula (II), u is 0 or 1, v is 0 or a positive integer, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, w is 0 or 1, R 61 ~R 78 And R a1 and R b1may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring.

[0034] [ka]

[0035] In the above general formula (III), x and d are 0 or an integer of 1 or more, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, y and z are 0, 1, or 2, and R 81 ~R 99 may be the same or different, and each is a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an alkoxy group; R 89 and R 90 and the carbon atom to which R is bonded. 93 or the carbon atom to which R is attached 91 may be bonded directly or via an alkylene group having 1 to 3 carbon atoms, and when y=z=0, R 95 and R 92 or R 95 and R 99 may be bonded to each other to form a monocyclic or polycyclic aromatic ring.

[0036] [ka]

[0037] In the above general formula (IV), R 100 , R 101 may be the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and f is 1≦f≦18.

[0038] The olefin monomer, which is one of the copolymerization raw materials for the copolymer (A1) in this embodiment, undergoes addition copolymerization to form the constitutional unit represented by the above general formula (I). Specifically, an olefin monomer represented by the following general formula (Ia) corresponding to the above general formula (I) is used.

[0039] [ka]

[0040] In the above general formula (Ia), R 300 represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. Examples of the olefin monomer represented by the general formula (Ia) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. From the viewpoint of obtaining optical components having better heat resistance, mechanical properties, and optical properties, ethylene and propylene are preferred, and ethylene is particularly preferred. Two or more types of olefin monomers represented by the general formula (Ia) may be used.

[0041] When the total of the structural units constituting the cyclic olefin copolymer in this embodiment is taken as 100 mol %, the proportion of the olefin-derived repeating unit (a) is preferably 5 mol % or more and 95 mol % or less, more preferably 20 mol % or more and 90 mol % or less, even more preferably 40 mol % or more and 80 mol % or less, and particularly preferably 50 mol % or more and 70 mol % or less. The proportion of repeating units (a) derived from olefins is as follows: 13 It can be measured by C-NMR.

[0042] The cyclic olefin monomer (b), which is one of the copolymerization raw materials of the copolymer (A1) in this embodiment, undergoes addition copolymerization to form the repeating unit (b) derived from the cyclic olefin represented by the above general formula (II), the above general formula (III), or the above general formula (IV). Specifically, the cyclic olefin monomer (b) represented by the general formulas (IIa), (IIIa), and (IVa) corresponding to the above general formulas (II), (III), and (IV), respectively, is used.

[0043] [ka]

[0044] In the above general formula (IIa), u is 0 or 1, v is 0 or a positive integer, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, w is 0 or 1, R 61 ~R 78 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring.

[0045] [ka]

[0046] In the above general formula (IIIa), x and d are 0 or an integer of 1 or more, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, y and z are 0, 1, or 2, and R 81 ~R 99may be the same or different, and each is a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an alkoxy group; R 89 and R 90 and the carbon atom to which R is bonded. 93 or the carbon atom to which R is attached 91 may be bonded directly or via an alkylene group having 1 to 3 carbon atoms, and when y=z=0, R 95 and R 92 or R 95 and R 99 may be bonded to each other to form a monocyclic or polycyclic aromatic ring.

[0047] [ka]

[0048] In the above general formula (IVa), R 100 , R 101 may be the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and f is 1≦f≦18.

[0049] By using the olefin monomer represented by the above-mentioned general formula (Ia) or the cyclic olefin monomer (b) represented by the general formula (IIa), (IIIa) or (IVa) as the copolymerization component, the solubility of the cyclic olefin copolymer (A) in a solvent is further improved, resulting in good moldability and improved product yield.

[0050] Specific examples of the cyclic olefin monomer (b) represented by the general formula (IIa), (IIIa) or (IVa) that can be used include the compounds described in paragraphs 0037 to 0063 of WO 2006 / 0118261.

[0051] Specifically, bicyclo-2-heptene derivatives (bicyclohept-2-ene derivatives), tricyclo-3-decene derivatives, tricyclo-3-undecene derivatives, tetracyclo-3-dodecene derivatives, pentacyclo-4-pentadecene derivatives, pentacyclopentadecadiene derivatives, pentacyclo-3-pentadecene derivatives, pentacyclo-4-hexadecene derivatives, pentacyclo-3-hexadecene derivatives, hexacyclo-4-heptadecene derivatives, and heptacyclo-5-eicosene. derivatives, heptacyclo-4-eicosene derivatives, heptacyclo-5-heneicosene derivatives, octacyclo-5-docosene derivatives, nonacyclo-5-pentacosene derivatives, nonacyclo-6-hexacosene derivatives, cyclopentadiene-acenaphthylene adducts, 1,4-methano-1,4,4a,9a-tetrahydrofluorene derivatives, 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene derivatives, and cycloalkylene derivatives having 3 to 20 carbon atoms.

[0052] Cyclic olefin monomer (b) represented by general formula (IIa), (IIIa) or (IVa) Among these, the cyclic olefin represented by the general formula (IIa) is preferred. Examples of the cyclic olefin monomer (b) represented by the above general formula (IIa) include bicyclo[2.2.1]-2-heptene (also called norbornene), tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene (also called tetracyclododecene), and at least one selected from tetracyclo[4.4.0.1 2,5 .1 7,10 It is more preferable to use ]-3-dodecene. These cyclic olefins have a rigid ring structure, and therefore have the advantage that the elastic modulus of the copolymer and the optical component can be easily maintained.

[0053] When the total of the structural units constituting the copolymer (A1) in this embodiment is taken as 100 mol %, the proportion of the repeating units (b) derived from the cyclic olefin monomer (b) is preferably 5 mol % or more and 95 mol % or less, more preferably 10 mol % or more and 80 mol % or less, even more preferably 20 mol % or more and 60 mol % or less, and particularly preferably 30 mol % or more and 50 mol % or less.

[0054] The copolymer type of the copolymer (A1) in this embodiment is not particularly limited, and can be, for example, a random copolymer, a block copolymer, etc. In this embodiment, from the viewpoint of obtaining optical components having excellent optical properties such as transparency, refractive index, and birefringence and high precision, it is preferable to use a random copolymer as the copolymer (A1) in this embodiment.

[0055] The copolymer (A1) in this embodiment is a copolymer of ethylene and tetracyclo[4.4.0.1 2,5 .1 7,10 Preferably, the copolymer is at least one selected from the group consisting of a random copolymer of ethylene and bicyclo[2.2.1]-2-heptene and a random copolymer of ethylene and tetracyclo[4.4.0.1 2,5 .1 7,10 A random copolymer with 1-dodecene is more preferred. In the present embodiment, the cyclic olefin copolymer (A) may be used alone or in combination of two or more kinds.

[0056] The lower limit of the content of copolymer (A1) contained in the cyclic olefin copolymer (A) in this embodiment is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the cyclic olefin copolymer (A) contained in the optical component in this embodiment is 100% by mass. By the content of copolymer (A1) in the cyclic olefin copolymer (A) in this embodiment being the above lower limit or more, the optical performance can be further improved.

[0057] The upper limit of the content of copolymer (A1) contained in the cyclic olefin copolymer (A) in this embodiment is not particularly limited, but is 100 mass% or less when the cyclic olefin copolymer (A) contained in the optical component in this embodiment is taken as 100 mass%.

[0058] The copolymer (A1) in this embodiment can be produced by appropriately selecting the conditions according to the methods described in, for example, JP-A-60-168708, JP-A-61-120816, JP-A-61-115912, JP-A-61-115916, JP-A-61-271308, JP-A-61-272216, JP-A-62-252406, JP-A-62-252407, etc.

[0059] From the viewpoint of the effects of the present invention, the glass transition temperature of the cyclic olefin copolymer (A) according to this embodiment is preferably higher than 120°C and not higher than 170°C, more preferably 125°C or higher and 160°C or lower, and even more preferably 130°C or higher and 155°C or lower.

[0060] The glass transition temperature of the cyclic olefin copolymer (A) according to this embodiment can be controlled, for example, by the type and amount of repeating units contained in the cyclic olefin copolymer (A) and the production conditions.

[0061] The glass transition point (Tg) of the cyclic olefin copolymer (A) according to the present embodiment can be measured, for example, by using a differential scanning calorimeter (DSC). For example, the glass transition point can be measured by using RDC220 manufactured by SII Nano Technology Co., Ltd., raising the temperature from room temperature to 200°C at a heating rate of 10°C / min under a nitrogen atmosphere, holding the temperature for 5 minutes, then lowering the temperature to 30°C at a heating rate of 10°C / min, holding the temperature for 5 minutes, and then raising the temperature to 200°C at a heating rate of 10°C / min.

[0062] (Other Ingredients) In addition to the cyclic olefin copolymer (A), the resin composition in this embodiment may contain known additives as optional components within a range that does not impair the excellent physical properties of the optical component in this embodiment.

[0063] Examples of the additives include hydrophilic stabilizers, hydrophilic agents, antioxidants, secondary antioxidants, lubricants, release agents, anti-fogging agents, weather resistance stabilizers, light resistance stabilizers, ultraviolet absorbers, antistatic agents, and metal deactivators.

[0064] Among the above, the resin in this embodiment preferably contains a hydrophilic stabilizer, which is more preferable since the deterioration of optical performance under high temperature and high humidity conditions can be suppressed by containing a hydrophilic stabilizer. The hydrophilic stabilizer is preferably a fatty acid ester of a fatty acid and a polyhydric alcohol, more preferably a fatty acid ester of a fatty acid and a polyhydric alcohol having one or more ether groups.

[0065] In this embodiment, the lower limit of the content of the cyclic olefin copolymer (A) in the resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire resin composition is 100% by mass. By making the content of the cyclic olefin copolymer (A) in the resin composition the lower limit or more, the optical performance can be further improved. The upper limit of the content of the cyclic olefin copolymer (A) in the resin composition is not particularly limited, but is, for example, 100 mass % or less.

[0066] [Process c] In this step, the molten resin obtained in step b is injected from the injection nozzle of the injection unit through a gate 18 into a cavity 16 (FIG. 1(a)). The injection pressure when injecting the resin from the injection nozzle into the mold can be appropriately selected and set in consideration of the structure of the mold, the fluidity of the resin, and other conditions, but is usually 500 to 15,000 kgf / cm. 2 This is carried out within the range.

[0067] The temperature of the mold can be appropriately determined depending on the glass transition temperature (Tg) and melting point (Tm) of the resin having an alicyclic structure, but is usually "Tg-30°C" to "Tg+10°C", preferably "Tg-20°C" to "Tg".

[0068] [Step d] In this process, molten resin is injected into 80% or more of the inner volume of the molding region 16a of the cavity 16, and while pushing the ejection core 15 provided in the second mold into the molding region 16a, the molten resin is injected until the inner volume of the molding region 16a reaches 100%. Next, a dwell pressure is applied to the molten resin in the cavity 16 from the injection unit side, and the molten resin is pressed by the ejection core 15.

[0069] In this way, when a predetermined amount of molten resin is injected, the molten resin can be uniformly pressed across the entire molding surface 15a, which has a predetermined area, of the protruding core 15, thereby improving the mold transferability, resulting in an optical component having a desired shape and reduced surface roughness of the optical surface, and further resulting in an optical component with a small average birefringence near the gate portion.

[0070] If the ejection core 15 is pressed in when the filling rate of the molten resin is less than 80% of the inner volume of the molding area 16a, the ejection core 15 narrows the flow path through which the molten resin passes, making it easier for the resin to be oriented, resulting in an increase in the amount of birefringence in the molded product, and in the lack of a compression effect, which reduces the transferability of the mold to the molded product and causes surface roughness in the optical surface.

[0071] Therefore, from the viewpoint of the effect of the present invention, the filling rate of the molten resin in the molding region 16a at the time of pushing in the ejection core 15 can be 80% or more, preferably 85% or more, and more preferably 90% or more of the inner volume of the molding region 16a. The upper limit is not particularly limited, but can be 100% or less, preferably 99% or less, and more preferably 98% or less.

[0072] The time for which the dwell pressure is applied and the time for which a compressive force is applied to the molten resin in the mold using the ejection core 15 do not have to be completely the same. The holding pressure is the pressure applied to the resin in the mold after it has been filled with the resin, until the resin at the gate of the mold is completely cooled and solidified. Even after the resin has been filled into the mold, holding pressure can be applied to the resin in the mold by operating the screw of the injection unit for a predetermined period of time.

[0073] The pressure and time for dwelling can be appropriately determined depending on the size and shape of the optical component. The dwelling pressure is usually 10 to 200 MPa, preferably 20 to 140 MPa. The dwelling time is usually 2 to 30 seconds.

[0074] The ejection core 15 is pushed into the molding region 16a in the first mold direction 12. That is, the ejection core 15 is moved 0.30 mm to 3 mm, preferably 0.4 mm to 2 mm, and more preferably 0.5 mm to 1 mm (from FIG. 1(a) to FIG. 1(b)), and the molten resin is pressed against the molding surface 12a having a predetermined area. This improves mold transferability and provides the effects of the present invention. The pressure applied to the molten resin by pushing the ejection core 15 and the pushing time are appropriately adjusted. The time for which the dwell pressure is applied and the time for which a compressive force is applied to the resin in the mold using the ejection core 15 do not have to be completely the same.

[0075] After step d, the resin in the mold is cooled and solidified according to a conventional method, and then the mold is opened to remove the resin molded product (optical component). The cooling time is not particularly limited, but is usually 1 to 500 seconds.

[0076] [Optical components] The resin molded body (optical component) obtained by the manufacturing method of this embodiment has a circular effective optical surface (a portion surrounded by an inner circle, diameter b) on surface R1 when viewed from above, and a circular effective optical surface (diameter c) on surface R2, which is the back surface, as shown in FIG. The manufacturing method of this embodiment is excellent in terms of mold transferability, and the optical surfaces of the obtained optical components are suppressed from having surface roughness.

[0077] The optical component obtained by the manufacturing method of this embodiment has a desired shape according to the mold design, and both the surface shape fluctuation PV value in the resin flow direction (MD direction) and the surface shape fluctuation PV value in the direction perpendicular to the resin flow (TD direction) shown in Figure 2 are small. The PV value can be 2.0 μm or less, preferably 1.5 μm or less, and more preferably 1.0 μm or less. The smaller the PV value, the better, so the lower limit is not particularly limited, but is, for example, 0.1 μm or more.

[0078] Here, the PV value refers to the difference between the point (Peak) where the shape error from the design value of the molding die is the largest and the point (Valley) where the shape error from the design value of the molding die is the smallest. The PV value and ΔPV can be measured by measuring the shape of the lens surface with a three-dimensional measuring device, and specifically can be evaluated by the method described in the Examples. Furthermore, the manufacturing method of this embodiment has excellent mold transferability, and the obtained optical component has a small average birefringence in the vicinity of the gate 18 . The average birefringence is in the 5mm x 5mm square area (25mm 2 ) is the average value of the phase difference at wavelengths of 523 nm, 543 nm, and 575 nm.

[0079] The optical component according to this embodiment contains the cyclic olefin copolymer (A), and therefore has excellent optical performance. Therefore, it can be suitably used as an optical component in an optical system that requires highly accurate identification of an image. The optical component is a component used in optical equipment, and specifically includes a sensor lens, a pickup lens, a projector lens, a prism, an fθ lens, an imaging lens, a light guide plate, etc., and from the viewpoint of the effect according to this embodiment, it can be suitably used as an fθ lens, an imaging lens, a sensor lens, a prism, or a light guide plate.

[0080] Examples of the lens shape include a convex lens with spherical surfaces on both sides, a concave lens with spherical surfaces on both sides, a lens with one spherical and convex surface and the other aspherical surface, a lens with one spherical and concave surface and the other aspherical surface, a lens with one spherical and convex surface and the other flat surface, a lens with one aspherical and convex surface and the other flat surface, a diffractive lens, a Fresnel lens, a wafer lens, a wafer lens array, and a laminate of wafer lens arrays.

[0081] In particular, the optical component according to this embodiment has a desired shape, the surface roughness of the optical surface is suppressed, and the average birefringence amount near the gate portion is small, so that it can be used not only for the above-mentioned conventional optical component applications, but also for optical components such as in-vehicle camera lenses and camera lenses for mobile devices (mobile phones, smartphones, tablets, etc.). Examples of in-vehicle camera lenses and camera lenses for mobile devices include view camera lenses, sensing camera lenses, lenses for light convergence in head-up displays, lenses for light diffusion in head-up displays, and lenses in various optical devices such as cameras for personal computers, cameras for mobile phones, cameras for smartphones, cameras for tablet terminals, cameras for mobile devices, digital cameras, and cameras for medical devices. The in-vehicle camera may be one that captures visible images, infrared images, or both, and in the case of visible images, it may be a black-and-white image or a color image. In addition, examples of applications other than the above include automobile interior panels, automobile lamp lenses, automobile inner lenses, automobile lens protective covers, automobile light guides, and the like. The optical component according to this embodiment can be particularly suitably used for in-vehicle applications.

[0082] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. EXAMPLES

[0083] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0084] <Production Example> <Preparation of Resin Composition A> (Catalyst Preparation) VO(OC 2 H 5 )Cl 2 was diluted with cyclohexane to prepare a vanadium catalyst with a vanadium concentration of 6.7 mmol / L-cyclohexane. 2 H 5 ) 1.5 Cl 1.5 ) was diluted with cyclohexane to prepare an organoaluminum compound catalyst having an aluminum concentration of 107 mmol / L-hexane.

[0085] (polymerization) A stirred polymerization vessel (inner diameter 500 mm, reaction volume 100 L) was used to continuously polymerize ethylene and tetracyclo[4.4.0.1 2,5 .1 7,10 A copolymerization reaction was carried out with ethylene and 1-3-dodecene. Here, ethylene was fed into the polymerization vessel together with hydrogen gas. When carrying out this copolymerization reaction, the vanadium catalyst prepared by the above method was fed into the polymerization vessel in such an amount that the vanadium catalyst concentration relative to the cyclohexane used as the polymerization solvent in the polymerization vessel was 0.6 mmol / L. In addition, ethylaluminum sesquichloride, an organoaluminum compound, was fed into the polymerization vessel in such an amount that Al / V=18.0. The polymerization temperature was set to 8°C, and the polymerization pressure was set to 1.8 kg / cm. 2 As G, the copolymerization reaction was carried out continuously.

[0086] (Decalcification) Ethylene and tetracyclo[4.4.0.1 2,5 .1 7,10The polymerization reaction was terminated by adding water and a 25% by weight aqueous solution of sodium hydroxide as a pH regulator to the copolymer solution. The catalyst residues present in the copolymer were removed (demineralized) from the copolymer solution. 2,5 .1 7,10 To a cyclohexane solution (polymer concentration 7.7% by mass) of a copolymer of 3-dodecene and pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] was added as a stabilizer such that the amount added to the copolymer was 0.4 parts by mass per 100 parts by mass of the copolymer. Then, before entering the flash drying process, the copolymer was temporarily dried in a 1.0 m 3 The mixture was mixed for 1 hour using a stirring tank.

[0087] (Desolvation) A cyclohexane solution of the copolymer, with the concentration of the copolymer in the cyclohexane solution being 5% by mass, was supplied at a rate of 150 kg / h to a double-tube heater (outer tube diameter 2B, inner tube diameter 3 / 4B, length 21 m) using steam at 20 kg / cm2G as a heat source, and heated to 180°C. Using a double-tube flash dryer (outer tube diameter 2B, inner tube diameter 3 / 4B, length 27m) using steam at 25kg / cm2G as a heat source and a flash hopper (volume 200L), the majority of the unreacted monomers were removed together with the polymerization solvent cyclohexane from the cyclohexane solution of the copolymer that had undergone the heating process, resulting in flash-dried molten ethylene and tetracyclo[4.4.0.1 2,5 .1 7,10 A random copolymer with cycloolefin-based copolymer (A-1) and 1,2-diphenyl-3-dodecene was obtained. The glass transition temperature Tg (°C) of the cycloolefin-based copolymer (A-1) was evaluated by the method described below and was found to be 155°C.

[0088] (Extrusion) Exepar PE-MS (Kao Corporation) was used as a fatty acid ester and heated at 100°C for 4 hours in a molten state, which was then directly charged into a vented twin-screw kneading extruder in an amount of 2.1 parts by mass per 100 parts by mass of the cyclic olefin copolymer (A-1). The molten state was then mixed with the cyclic olefin copolymer (A-1) charged through the resin charging section of the extruder and pelletized using an underwater pelletizer attached to the outlet of the extruder. The resulting pellets were then dried with hot air at a temperature of 100°C for 4 hours to obtain resin composition A-1.

[0089] [Glass transition temperature Tg(℃)] Shimadzu Science Corporation, DSC-6220 was used. 2 The glass transition temperature Tg of the cyclic olefin copolymer was measured under a nitrogen atmosphere. The cyclic olefin copolymer was heated from room temperature to 200°C at a heating rate of 10°C / min, held for 5 minutes, then cooled to -20°C at a heating rate of 10°C / min, held for 5 minutes. The glass transition temperature (Tg) of the cyclic olefin copolymer was obtained from the endothermic curve when the temperature was raised to 200°C at a heating rate of 10°C / min. The glass transition temperature (Tg) was 140°C.

[0090] (Fabrication of optical components) <Example 1> The optical components were manufactured using an injection molding machine equipped with molds having the following sizes: As shown in FIG. 1(a), the ejection core was moved by the compression amount shown in Table 1 in the direction opposite to the direction of the first mold 12. The resin composition A-1 was put into the injection unit and melted at a cylinder temperature of 260° C., and the molten resin was injected from the injection unit into the cavity 16 through the gate 18. When the molten resin was injected into 97% or more of the inner volume of the molding region (optically effective portion) 16a in the mold 10 (mold temperature 120° C.), the ejection core 15 provided in the second mold 14 was moved by the compression amount shown in Table 1, pushed into the molding region 16a, and the molten resin was pressed, and the resin was injected into 100% of the inner volume of the molding region (optically effective portion) 16a in the mold 10 (mold temperature 120° C.), and then the molten resin in the cavity 16 was subjected to a dwell pressure shown in Table 1, and the resin in the mold was cooled and solidified, and then the mold was opened to obtain a resin molded product (optical component). (Mold size) Diameter (width) b of molding surface 12a of first mold 12: φ28 mm Area of ​​molding surface 12a: 615mm 2 Diameter (width) c of molding surface 15a of extrusion core 15: φ26.9 mm Area of ​​molding surface 15a: 568mm 2 Thickness a of molding area (optically effective part) 16a: 2.7mm Gate 18 width: 1.2mm Lens shape: Meniscus lens

[0091] <Example 2, Comparative Examples 1 to 3> A resin molded article (optical part) was prepared in the same manner as in Example 1, except that the conditions shown in Table 1 were used.

[0092] <Example 3 and Comparative Example 4> A resin molded product (optical part) was prepared in the same manner as in Example 1, except that the size of the mold was changed as follows and the conditions shown in Table 1 were used. Diameter (width) b of molding surface 12a of first mold 12: φ46 mm Area of ​​molding surface 12a: 1661mm 2 Diameter (width) c of the molding surface (flat surface) 15a of the ejection core 15: φ46 mm Area of ​​molding surface 15a: 3524mm 2 Thickness of molding area (optically effective area) 16a: 10mm Gate 18 width: 2mm Lens shape: Plano-convex lens

[0093] [Evaluation methods for optical components] The obtained optical components were evaluated by the following methods.

[0094] [Lens shape] The lens surface shape of the optical components of the examples and comparative examples was measured using an ultra-high precision 3D measuring device UA3P (manufactured by Panasonic). Measurements were performed using a diamond stylus with a tip curvature radius of 2 μm at a measurement speed of 0.1 mm / s for the R1 and R2 surfaces of the optical components, over a range of 87% of the effective diameter (diameter 6 mm), in both the MD and TD directions, and the PV value was calculated. Here, the difference between the point where the shape error of the forming mold is greatest from the design value (Peak) and the point where the shape error of the forming mold is least from the design value (Valley) is called the PV value, taking the initials of the two. The R1 surface is the surface on the first mold 12 side in injection molding, and the R2 surface is the surface on the second mold 14 side in injection molding. As shown in Fig. 2, the MD direction indicates the direction of resin flow, and the TD direction indicates the direction perpendicular to the resin flow. Evaluation was based on the following criteria. (standard) ○: PV values ​​in both MD and TD directions are 2μm or less ×: Either the PV value in the MD direction or the TD direction is greater than 2 μm

[0095] [Birefringence] The phase difference of the obtained optical component was measured in a 5 mm x 5 mm square area at the gate position shown in Figure 2 using a wide range birefringence evaluation system (Photonic Lattice WPA-200) at three wavelengths (wavelengths of 523 nm, 543 nm, and 575 nm), and the average value was calculated. Evaluation was based on the following criteria. (standard) ○: Average phase difference is 10 nm or less ×: The average retardation value is greater than 10 nm

[0096] [Surface roughness] The optically effective surface of surface R1 of the optical component was observed with an optical microscope (25x). The evaluation was based on the following criteria. (standard) 〇: No surface roughness ×: Surface roughness occurs FIG. 3 shows an optical microscope photograph of the optically effective surface (no surface roughness) of the optical component obtained in Example 1, and FIG. 4 shows an optical microscope photograph showing the surface roughness that occurred on the optically effective surface of the optical component obtained in Comparative Example 1.

[0097] [Table 1]

[0098] As shown in Table 1, it has become clear that the manufacturing method of optical components using a specific injection molding machine of the present invention has excellent mold transferability, and therefore it is possible to obtain optical components with a small PV value, a desired shape, suppressed surface roughness of the optical surface, and a small average birefringence near the gate. Since the optical components obtained by the manufacturing method of the present invention have these properties, they can be suitably used as various lenses. [Explanation of symbols]

[0099] 1 Injection molding equipment 10. Mold 12 First Mold 12a Molding surface 14 Second mold 15 Protruding core 15a Molding surface 16 Cavity 16a Molding area 18 Gates a Width of the forming area b Width (diameter) of molding surface 12a c Width (diameter) of molding surface 15a

Claims

1. a mold having an injection unit, a cavity including a molding region a for molding an optical component having an optical surface, and a gate serving as an injection port for injecting molten resin from the injection unit into the cavity; the mold is composed of a pair of a first mold and a second mold, and has the cavity including the molding region a between these molds, The first mold has an area of ​​310 mm for forming the optical surface. ２ More than 5030mm ２ The molding surface is as follows in the molding region a: The second mold is provided with an opening that is provided in a position opposite to the first mold and opens into the molding region a, and an ejection core that is configured to be slidable in the direction of the first mold within the opening, and the ejection core has an area of ​​310 mm ２ More than 5030mm ２ The molding surface is as follows in the molding region a: a distance between the molding surface of the first mold and the molding surface of the second mold in the molding region a is 2 mm or more and 15 mm or less, a step of moving the ejection core by 0.30 mm or more and 3 mm or less in a direction opposite to the first mold direction to widen a width between the first mold and the second mold in the molding region a of the cavity, thereby expanding the molding region a to a molding region b; Melting a resin composition containing ethylene or a copolymer of an α-olefin and a cyclic olefin; A step of injecting the molten resin composition from the injection unit through the gate into the expanded molding region b; a step of injecting the molten resin composition into the molding region b of the cavity so that the inner volume of the molding region a is 80% or more and 99% or less, and then injecting the molten resin composition into the molding region a to 100% of the inner volume of the molding region a while pushing the ejection core provided in the second mold into the molding region a, and then applying a dwell pressure to the molten resin composition in the cavity from the injection unit side while pressing the molten resin composition with the ejection core; A method for manufacturing an optical component, comprising:

2. A method for manufacturing an optical component as described in claim 1, wherein the step of expanding the molding area is a step of moving the ejection core by 0.5 mm or more and 3 mm or less in a direction opposite to the first mold direction, thereby widening the width between the first mold and the second mold in the molding area of ​​the cavity.

3. The method for manufacturing an optical component according to claim 1 , wherein the gate is formed between the first mold and the second mold and communicates with the cavity.

4. The method for producing an optical component according to any one of claims 1 to 3, wherein the copolymer has a glass transition temperature of more than 120°C and not more than 170°C.

5. The copolymer is At least one olefin-derived repeating unit (a) represented by the following general formula (I); A repeating unit represented by the following general formula (II) and a repeating unit represented by the following general formula (III) and at least one repeating unit (b) derived from a cyclic olefin selected from the group consisting of repeating units represented by the following general formula (IV): The method for producing an optical component according to any one of claims 1 to 4, comprising: 【Chemistry 1】 (In the above general formula (I), R ３００ represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. 【Chemistry 2】 (In the above general formula (II), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, R61 to R78 and R ａ１ and R ｂ１ may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R ７５ ~R ７８ may be bonded to each other to form a monocyclic or polycyclic ring.) 【Chemistry 3】 (In the general formula (III), x and d are 0 or an integer of 1 or more, y and z are 0, 1 or 2, and R ８１ ~R ９９ may be the same or different, and each is a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an alkoxy group; R ８９ and R ９０ and a carbon atom to which R ９３ or the carbon atom to which R ９１ may be bonded directly or via an alkylene group having 1 to 3 carbon atoms, and when y=z=0, R ９５ and R ９２ Or R ９５ and R ９９ may be bonded to each other to form a monocyclic or polycyclic aromatic ring. 【Chemistry 4】 (In the general formula (IV), R １００ , R １０１ may be the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and f is 1≦f≦18.

6. The repeating unit (b) derived from the cyclic olefin in the copolymer (A1) is selected from the group consisting of bicyclo[2.2.1]-2-heptene and tetracyclo[4.4.0.1 ２，５ .1 ７，１０ 6. The method for producing an optical component according to claim 5, wherein the repeating unit is derived from at least one compound selected from the group consisting of 1-dodecene and 2-diphenyl ether.

7. The method for producing an optical component according to claim 5 or 6, wherein the olefin-derived repeating units (a) in the copolymer (A1) include repeating units derived from ethylene.

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