JP2013190712A - Manufacturing method of optical lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical lens, the method being capable of forming a hard coat film having a uniform distribution of film thickness on a lens base material, though thick in film thickness.SOLUTION: The manufacturing method of an optical lens includes: an immersion step to immerse a lens base material into a coating liquid(S21); a lifting step to lift the lens base material from the coating liquid by providing a period in which a lifting speed is reduced until the lens base material is completely exposed after starting to be exposed from the coating liquid (S22); a curing step to form a hard coat film by subjecting the coating liquid applied on the surface of the lens base material to curing process (S24); and a determining step to determine the repeating plural times of the immersion step (S21) to the curing steps (S24, S24') until the hard coat film becomes a predetermined film thickness (S23).

Description

  The present invention relates to an optical lens manufacturing method, and more particularly to an optical lens manufacturing method capable of forming a hard coat film thickened by a dipping method.

  For eyeglass users, the risk of scratching the lens surface is always a problem. Many scratches on the lens are caused by collision or friction of an object, and for the purpose of preventing this, many spectacle lenses are provided with an organic hard coat film and an inorganic antireflection film. Among these, the hard coat film is a film harder than the lens substrate, and has an effect of preventing scratches, and also acts as an intermediate layer for providing adhesion to the antireflection film thereon. In addition, the antireflection film is often an inorganic multilayer film having a higher hardness than the hard coat film, and in addition to the conventional action of preventing reflection of reflected light, the action of preventing scratches is added. It has become like this.

  By the way, when forming a hard coat film on a lens substrate, coating methods such as a dipping method, a spin method, and a spray method are generally used. The dipping method is a method in which a plastic lens is immersed in a hard coat solution and then pulled up. The spin method is a method of spreading the hard coat film uniformly by rotating the plastic lens while dripping the hard coat solution onto the plastic lens. The spray method is a method in which a hard coat liquid is sprayed onto a plastic lens from a spray nozzle.

  Of these, the dipping method is the simplest method, and a hard coat film with good uniformity is formed by adjusting the pulling rate within a range of 10 to 1000 mm / min (see Patent Document 1 below). ).

JP 2000-189884 A (see, for example, paragraph 0035)

  However, the thickness of the hard coat film formed by the dipping method as described above is only about 2 to 3 μm, and it is difficult to form a hard coat film having a larger thickness. On the other hand, although it is possible to form a hard coat film having a film thickness of several μm to several tens of μm by the spin method and several tens μm to several hundred μm by the spray method, there is a problem that it is difficult to manage the film thickness distribution. It was.

  Accordingly, an object of the present invention is to provide a method of manufacturing an optical lens that can form a hard coat film having a uniform film thickness distribution on a lens substrate while being a thick film.

  In order to achieve such an object, the present invention provides a dipping step of immersing a lens substrate in a coating solution and a period from the start of exposure of the lens substrate to the complete exposure from the coating solution. , A lifting step for raising the lens base material from the coating liquid by providing a period for slowing the lifting speed, and a curing process step for curing the coating liquid applied to the surface of the lens base material to form a hard coat film And a determination step of determining that the above immersion step, the pulling step, and the curing treatment step are repeated a plurality of times until the hard coat film has a predetermined thickness.

  According to such a manufacturing method, when the lens base material is lifted from the coating liquid, by performing a pulling step provided with a period for decelerating the pulling speed, as described in a later example, It was found that the uniformity of the film thickness within the lens surface was ensured. And by repeatedly performing such pulling up across the curing process of the coating liquid, a hard coat film with high in-plane uniformity is overcoated, and a hard coat film with high film thickness uniformity is made thicker It becomes possible to do.

  The immersion process to the curing process as described above are performed in a state where the lens surface of the lens substrate is held substantially vertically.

  In the repeated pulling process, the lens base is pulled up with the same one end set at the periphery of the lens base as the upper end. Thereby, dripping from the holder holding the lens base material is prevented, and a hard coat film having a uniform film thickness is obtained on the entire surface extending to the periphery of the lens base material.

  Further, in each pulling step, the pulling speed of the lens base material is made constant at least one immediately after the lens base material starts to be exposed from the coating liquid and immediately before the lens base material ends the exposure. Thereby, the in-plane uniformity in the lens surface of the film thickness of the hard coat film can be improved as will be described in a later example.

  In addition, the determination process is performed between the pulling process and the curing process, and in the determination process, it is determined that the hard coat film has reached a predetermined film thickness in order to completely cure the coating liquid. The curing process is performed under conditions different from the previous one.

  As described above, according to the method for manufacturing an optical lens of the present invention, it is possible to form a hard coat film having a uniform film thickness distribution on a lens substrate while being a thick film.

It is a flowchart which shows one Embodiment of the manufacturing method of the optical lens which concerns on this invention. It is a schematic diagram (the 1) for describing one Embodiment of the manufacturing method of the optical lens which concerns on this invention. FIG. 6 is a schematic diagram (No. 2) for describing an embodiment of a method for producing an optical lens according to the present invention. It is a graph which shows the example of the raising speed of a lens base material. It is a cross-sectional schematic diagram of the optical lens produced in the embodiment.

  Hereinafter, an embodiment of a method for producing an optical lens according to the present invention will be described with reference to the drawings. In the present embodiment, a configuration in which the present invention is applied to a procedure for forming a hard coat film on a lens substrate will be described. However, the application of the present invention is not limited to this, and the present invention is not limited to this. In addition, the present invention can be widely applied when various optical films (for example, hard coat films) are formed to a certain degree of thickness.

  FIG. 1 is a flowchart showing an embodiment of a method for manufacturing an optical lens according to the present invention, and FIGS. 2 and 3 are schematic diagrams for explaining an embodiment of a method for manufacturing an optical lens according to the present invention. is there. First, according to the flowchart of FIG. 1, the manufacturing method of the optical lens of embodiment is demonstrated, referring FIG. 2, FIG.

<< Formation of primer layer (S1) >>
First, a primer layer is formed on the surface of the lens substrate (S1). Here, a plastic lens made of a plastic material shown below is used as the lens substrate. The primer layer provided on such a lens base material ensures the impact resistance of the lens base material, and in addition, ensures the adhesion between the hard coat film provided on the lens base material and the lens base material. belongs to. The primer layer may be made of a material that does not affect the optical characteristics when the lens substrate is made of a relatively high refractive index material.

  As a method for forming such a primer layer, it can be formed by applying a dipping method, a spin coat method, a spray method or the like and then curing it by heating, light irradiation or the like.

[Lens substrate]
The following materials can be used as the plastic material constituting the lens substrate. For example, methyl methacrylate homopolymer, copolymer having methyl methacrylate and one or more other monomers as monomer components, diethylene glycol bisallyl carbonate homopolymer, diethylene glycol bisallyl carbonate and one or more other monomers as monomer components Copolymer, sulfur-containing copolymer, halogen-containing copolymer, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, polythiourethane, homopolymer of monomer having sulfide bond, sulfide and Copolymers containing one or more other monomers as monomer components, copolymers containing polysulfides and one or more other monomers as monomer components, polydisulfides and one or more other monomers as monomers A copolymer such as a component. Further, as a material for the lens substrate, a relatively high refractive index material having a refractive index of about 1.6 or more may be used.

  Such a primer layer forming step may be performed as necessary, and may be omitted if not necessary.

<< Formation of hard coat film (S2) >>
Next, a hard coat film is formed on the surface of the lens substrate via a primer layer (S2). The hard coat film is usually formed by a coating method such as dipping, spin coating, or spraying. Here, the hard coat film is formed by the dipping method, and the hard coat film is formed by the following procedure. To do.

<Immersion process (S21)>
First, an immersion step (S21) in which the lens substrate is immersed in the coating solution is performed. The coating liquid used here is a hard coat liquid containing a forming material for forming a hard coat film, as will be described in detail later. Here, as shown in FIG. 2, the entire lens base material 1 is completely immersed in the coating liquid L so that the entire lens base material 1 is below the liquid level PL of the coating liquid L. . At this time, the lens substrate 1 in the coating liquid L is held, for example, so that the lens surface 1a is substantially perpendicular to the liquid level PL.

  The lens substrate 1 is held by the holding member 3 that holds the lens substrate 1 at the outer peripheral portion. The holding member 3 is arranged, for example, at three locations on the outer periphery of the lens base material 1 with substantially equal intervals, and holds the lens base material 1 at these three locations. Although not shown here, these holding members 3 are fixed to an arm that can move the holding member 3 up and down with respect to the liquid surface of the coating liquid L, and are held by the holding member 3 by the vertical movement of this arm. In addition, the lens substrate 1 can be freely immersed and pulled up in the coating liquid L.

  The lens base 1 is held by such fixing to the holding member 3 so that one end of the periphery of the lens base 1 becomes the upper end P1 and the other end on the opposite side becomes the lower end P2. The vicinity of the lower end P <b> 2 of the lens base 1 is held by one holding member 3, and both sides of the lens base 1 are held by two holding members 3. The holding member 3 that holds both sides of the lens base 1 is located at a position where the lens area A set in the center of the lens base 1 is removed, that is, outside the area where the lens area A extends in the vertical direction. Assume that material 1 is held. Thereby, the configuration is such that the influence of the liquid dripping from the holding member 3 does not reach the lens region A.

[Coating solution]
The coating liquid L (that is, hard coat liquid) is mainly composed of an organic polymer such as an organic silicon compound, so-called silane coupling material or organic epoxy material, and tin oxide or zirconia for the purpose of matching the refractive index with the lens substrate 1. It contains metal oxides such as Such a coating liquid L contains, for example, tin oxide sol or zirconia sol, one or more organic silicon compounds, and further another metal oxide or catalyst.

  For example, when a tin oxide sol is used as a coating solution (hard coating solution), the coating solution further accelerates the curing reaction of other metal oxides, organosilicon compounds, and coating solutions coated on a lens substrate. In order to improve the wettability at the time of application | coating to the lens base material and a lens base material, and to improve smoothness, surfactant and a surfactant (leveling agent) can also be contained. Furthermore, ultraviolet absorbers, antioxidants, light stabilizers and the like can be added as long as they do not affect the physical properties of the hard coat film. Each material contained in the coating liquid L is as follows.

[Metal oxide]
Examples of metal oxides include aluminum (Al), antimony (Sb), silicon (Si), cerium (Ce), iron (Fe), indium (In), zinc (Zn), titanium (Ti), and zirconium (Zr). One or more oxides or composite oxides of metals such as

  These metal oxides are added to the coating solution in a state dispersed in a solvent. Solvents for dispersing the metal oxide include alcohols such as methanol, ethanol and isopropanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol propyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl Known materials such as ethers, glycol ethers such as ethylene glycol monobutyl ether, glycols such as ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol, and ketones such as methyl ethyl ketone and methyl isobutyl ketone can be used.

[Organic silicon compound]
When using at least one selected from the group consisting of amino, isocyanate, epoxy, acrylic, vinyl, methacrylic, styryl, ureido, and mercapto silane coupling agents as the organosilicon compound It is suitable for. For example, at least one selected from an organosilicon compound represented by the following general formula (1), an organosilicon compound represented by the following general formula (2), and a hydrolyzate thereof can be used.

(R ¹ ) _n Si (OR ² ) _4-n ... General formula (1)

In the general formula (1), R ¹ is a monovalent carbon number of 3 to 20 having a functional group (amino group, isocyanate group, epoxy group, acrylic group, vinyl group, methacryl group, styryl group, ureido group, mercapto group). For example, γ-aminopropyl group, N-β (aminoethyl) -γ-aminopropyl group, N-phenyl-γ-aminopropyl group, γ-isocyanatepropyl group, γ-glycidoxypropyl Group, β-epoxycyclohexylethyl group, γ-acryloxypropyl group, vinyl group, γ-methacryloxypropyl group, p-styryl group, γ-ureidopropyl group, γ-mercaptopropyl group and the like.

In General Formula (1), R ² is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an acyl group having 2 to 10 carbon atoms. The alkyl group having 1 to 8 carbon atoms of R ² may be linear, branched or cyclic, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, Examples include isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group and the like. Examples of the aryl group include a phenyl group and a tolyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the acyl group include an acetyl group.

In formula (1), n represents an integer of 1 or 2, a plurality of R ¹ if R ¹ is more may be the same with or different from each other, a plurality of OR ² are the same as or different from each other It may be.

  Specific examples of the organosilicon compound represented by the general formula (1) include γ-aminopropyltrimethoxysilane, γ-aminopropyldimethoxymethylsilane, γ-aminopropyltriethoxysilane, γ-aminopropyldiethoxymethylsilane, N-β (aminoethyl) γ-aminopropyldimethoxymethylsilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (amino Ethyl) γ-aminopropyldiethoxymethylsilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyldimethoxymethylsilane, N-phenyl-γ-aminopropyltriethoxysilane, N-phenyl -Γ-aminopropyldiethoxymethyl , Γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyldimethoxymethylsilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyldiethoxymethylsilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Propyldimethoxymethylsilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyldiethoxymethylsilane, β-epoxycyclohexylethyltrimethoxysilane, β-epoxycyclohexylethyldimethoxymethylsilane, β-epoxycyclohexylethyltri Ethoxysilane, β-epoxycyclohexylethyldiethoxymethylsilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyldimethoxy Tylsilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropyldiethoxymethylsilane, vinyltrimethoxysilane, vinyldimethoxymethylsilane, vinyltriethoxysilane, vinyldiethoxymethylsilane, γ-methacryloxypropyltrimethoxysilane Γ-methacryloxypropyldimethoxymethylsilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyldiethoxymethylsilane, p-styryltrimethoxysilane, p-styryldimethoxymethylsilane, p-styryltriethoxysilane, p-styryldiethoxymethylsilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyldimethoxymethylsilane, γ-ureidopropyltriethoxysilane, γ- Raid propyl diethoxymethyl silane, .gamma.-mercaptopropyltrimethoxysilane, .gamma.-mercaptopropyl dimethoxymethyl silane, .gamma.-mercaptopropyl triethoxysilane, .gamma.-mercaptopropyl diethoxy methylsilane, and the like.

In the general formula (2), R ³ and R ⁴ are each an alkyl group having 1 to 4 carbon atoms or an acyl group having 2 to 4 carbon atoms, which may be the same or different, and R ⁵ and R ⁶ are These are monovalent hydrocarbon groups having 1 to 5 carbon atoms, each having or not having a functional group, which may be the same or different.

Examples of the alkyl group of R ³ and R ⁴ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and the like. Examples of the acyl group having 2 to 4 include an acetyl group.

Examples of the hydrocarbon group for R ⁵ and R ⁶ include an alkyl group having 1 to 5 carbon atoms and an alkenyl group having 2 to 5 carbon atoms. These may be either linear or branched, and examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. Group, pentyl group, and the like. Examples of the alkenyl group include vinyl group, allyl group, and butenyl group.
Examples of the functional group of the hydrocarbon group include a halogen atom, a glycidoxy group, an epoxy group, an amino group, a mercapto group, a cyano group, and a (meth) acryloyloxy group.

In the general formula (2), Y is a divalent hydrocarbon group having 2 to 20 carbon atoms, and preferably an alkylene group and alkylidene group having 2 to 10 carbon atoms, such as a methylene group, an ethylene group, a propylene group, Examples include butylene, ethylidene, and propylidene groups. In the general formula (2), a and b each represent an integer of 0 or 1, and a plurality of OR ³ may be the same or different, and a plurality of OR ⁴ may be the same or different. Good.

  Specific examples of the organosilicon compound represented by the general formula (2) include bis (triethoxysilyl) ethane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) methane, bis (trimethoxysilyl) hexane, Examples thereof include bis (triethoxysilyl) octane, and bis (triethoxysilyl) ethane and bis (trimethoxysilyl) ethane are preferable.

  Among the above materials, the organosilicon compound used in the hard coat liquid in the method for producing an optical lens in the present embodiment is at least selected from the group consisting of epoxy-based, acrylic-based, vinyl-based, and methacrylic-based silane coupling agents. It is desirable to include one or more types. Further, as other organosilicon compound, it is desirable to include at least one selected from the group consisting of amino-based and isocyanate-based silane coupling agents.

  Among these compounds, it is preferable to use at least one selected from an organosilicon compound having an amino group represented by the following general formula (3) and a hydrolyzate thereof.

(R ⁷ ) nSi (OR ⁸ ) _4-n ... General formula (3)

In the general formula (3), R ⁷ is a monovalent hydrocarbon group having 1 to 20 carbon atoms having an amino group, such as γ-aminopropyl group, N-β (aminoethyl) -γ-aminopropyl. Group, N-phenyl-γ-aminopropyl group and the like. In General Formula (3), R ⁸ is an alkyl group having 1 to ⁸ carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an acyl group having 2 to 10 carbon atoms. Examples of each group include the same examples as R ² described above. In general formula (3), n represents an integer of 1 or 2, it may be the same with or different from each other a plurality of R ⁷ is the case where R ⁷ is plural, OR ⁸ are also identical to each other May be different.

  Specific examples of the organosilicon compound represented by the general formula (3) include γ-aminopropyltrimethoxysilane, γ-aminopropyldimethoxymethylsilane, γ-aminopropyltriethoxysilane, and γ-aminopropyldiethoxymethylsilane. N-β (aminoethyl) γ-aminopropyldimethoxymethylsilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β ( Aminoethyl) γ-aminopropyldiethoxymethylsilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyldimethoxymethylsilane, N-phenyl-γ-aminopropyltriethoxysilane, N- Phenyl-γ-aminopropyldiethoxymethyl Amino-based silane coupling agents such as silane.

  Among these, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyldimethoxymethylsilane, and γ-aminopropyldiethoxymethylsilane are preferable, γ-aminopropyltrimethoxysilane, and γ-amino. More preferred are propyltriethoxysilane and γ-aminopropyltrialkoxysilane.

  In addition, it is desirable to use at least one selected from an organosilicon compound having an isocyanate group represented by the following general formula (4) and a hydrolyzate thereof.

(R ⁹ ) _n Si (OR ¹⁰ ) _4-n ... General formula (4)

In the above general formula (4), R ⁹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms having an isocyanate group, such as an isocyanate methyl group, an α-isocyanatoethyl group, a β-isocyanatoethyl group, an α- Examples thereof include an isocyanate propyl group, a β-isocyanate propyl group, and a γ-isocyanate propyl group.

In the general formula (4), R ¹⁰ is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an acyl group having 2 to 10 carbon atoms, Examples of these groups include the same examples as those for R ² .
In formula (4), n represents an integer of 1 or 2, a plurality of R ⁹ in the case where R ⁹ there are a plurality may be the same with or different from each other, a plurality of OR ¹⁰ is also identical to each other May be different.

  Examples of the compound represented by the general formula (4) include γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyldimethoxymethylsilane, γ-isocyanatopropyltriethoxysilane, and γ-isocyanatopropyldiethoxymethyl. Examples thereof include isocyanate-based silane coupling agents such as silane, and γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, and γ-isocyanatopropyltrialkoxysilane are preferable.

  The organosilicon compound as described above is added to the coating solution in a state of being dispersed or dissolved in a solvent. Such solvents include methanol, ethanol, isopropanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol propyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, It is desirable to use ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, diacetone alcohol, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and the like.

[Curing catalyst]
The curing catalyst is not particularly limited, but amines such as allylamine and ethylamine, and various acids and bases including Lewis acid and Lewis base, such as organic carboxylic acid, chromic acid, hypochlorous acid, boric acid, perchloric acid. And salts or metal salts having bromine acid, selenious acid, thiosulfuric acid, orthosilicic acid, thiocyanic acid, nitrous acid, aluminate, carbonic acid, metal alkoxides having zirconium or titanium, or metal chelate compounds thereof. .

<Pulling up process (S22)>
Next, a lifting step (S22) for lifting the lens substrate 1 from the coating liquid L is performed. Here, it is characteristic that a period during which the pulling speed of the lens base material 1 is decelerated is provided from when the lens base material 1 is exposed from the coating liquid L to when it is completely exposed.

  That is, as shown in FIG. 3, in this lifting step (S <b> 22), the lens surface 1 a of the lens base 1 is kept substantially perpendicular to the liquid surface PL of the coating liquid L from the inside of the coating liquid L. The lens substrate 1 is pulled up. At this time, when the upper end P1 of the lens base material 1 reaches the liquid level PL of the coating liquid L and when the lower end P2 of the lens base material 1 reaches the liquid level PL of the coating liquid L is defined as a pulling period, During the pulling-up period, a deceleration period for reducing the speed at which the lens substrate 1 is pulled up from the coating liquid L is provided. Such a deceleration period is provided at least in an intermediate part in the pulling period.

  Further, in the pulling-up period, the period other than the deceleration period described above is a constant speed period in which the pulling is performed at a constant speed. This constant speed period is provided at least one time immediately after the lens base material 1 starts exposure from the coating liquid L and immediately before the lens base material 1 finishes exposure during the pull-up period.

  FIG. 4 shows, as an example, the distance from the upper end P1 of the lens substrate 1 to the liquid level PL during the pulling period when the lens substrate 1 having a diameter of 75 mm is used (the distance from the upper end of the lens), and the lifting. The graph of the relationship with speed is shown. In this graph, two conditions of the pulling speed during the pulling period described above (distance 0 mm to 75 mm from the upper end of the lens) are illustrated.

  As shown here, the pulling speed during the pulling period is a deceleration period in which the first half is a constant speed period with a constant pulling speed and the middle plate is decelerated as in the pulling speed condition 1 The second half may be a constant speed period with a constant pulling speed. Further, as in the pulling speed condition 2, during the pulling period, the first half may be a deceleration period in which the pulling speed is reduced, and the second half may be a constant speed period in which the pulling speed is constant. Although not shown here, as another pulling speed condition, during the pulling period, the first half may be a constant speed period with a constant pulling speed, and the second half may be a deceleration period in which the pulling speed is reduced. .

  As described below, the above-described pulling step (S22) is repeated a plurality of times. In each pulling step (S22), the lens base material 1 is pulled up from the same upper end P every time. For this reason, in the repetition of the pulling-up step (S22), the lens base 1 is not rotated within the lens surface 1a or turned upside down. That is, when the lens base material 1 is pulled up from the coating liquid L, the portion of the lens base material 1 that reaches the liquid surface PL earliest is the upper end P1 of the lens base material 1 held by the holding member 3. In the repetition of the pulling process (S22), the upper end P1 does not move around the periphery of the lens substrate 1. Similarly, when the lens base material 1 is pulled up from the coating liquid L, the slowest part of the lens base material 1 that reaches the liquid surface PL is the lower end P2 of the lens base material 1 held by the holding member 3. In the repetition of the pulling step (S22), the upper end P1 does not move on the periphery of the lens substrate 1.

  In the lifting step (S22), the coating liquid applied to the lens surface 1a flows down from the holding member 3 that holds the vicinity of the lower end P2 of the lens substrate 1, and the excess coating liquid is removed. Yes.

<Judgment process (S23)>
Next, a determination step (S23) for determining whether or not the number of times of performing the previous pulling step (S22) has reached a predetermined n times is performed. In this determination step, it is indirectly determined whether or not the optical film formed through the pulling step (S22), that is, the hard coat film, has a predetermined film thickness by the number of repetitions of the pulling step (S22). . For this reason, the film thickness of the hard coat film formed through one pulling process (S22) is examined in advance, and the total film thickness of the hard coat film to be formed is set to a predetermined film thickness until the predetermined film thickness is reached. The number of repetitions (n times) is obtained as a prescribed number. The number of repetitions (n times) is also the number of times the hard coat film is formed by the dipping method.

  For example, if the hard coat film formed through one pulling step (S22) is 2 μm and it is desired to form a hard coat film with a total film thickness of 20 μm, the number of repetitions may be n = 10. .

  In the determination step (S23) as described above, when it is determined that the number has not reached n times (No), the process proceeds to the first processing step (S24). On the other hand, if it is determined that the number has reached n times (Yes), the process proceeds to the second processing step (S24 ').

<First curing process (S24)>
In the first curing process (S24), the coating liquid L applied to the surface of the lens substrate 1 in the previous pulling process (S22) is cured to form a hard coat film as an optical film. This curing process may be performed appropriately with a resin used as a main component of the hard coat film. For example, when a thermosetting resin is used, a curing process by heating is performed, and when a photocurable resin is used, a curing process with light irradiation and heating as necessary may be performed. However, in the first curing process step (S24), the coating liquid L is not completely cured, and curing is performed so as not to be dissolved by the hard coat liquid in the next dipping process (S21).

  Further, during the first curing treatment step (S24), the lens surface 1a is held so as to be substantially perpendicular to the liquid surface PL of the coating liquid L as in the previous pulling step (S22). At this time, the upper end P1 and the lower end P2 of the lens base 1 do not move at the periphery of the lens base 1 in the previous pulling step (S22), and the vertical relationship is maintained.

  Through the dipping process (S21), the pulling process (S22), and the first curing process (S24), the first hard coat film is formed by the dipping method (dipping method).

  After such a 1st hardening process process (S24), it returns to the immersion process (S21) demonstrated previously. In the determination step (S23) described above, the first curing process step (S24) to the immersion step (S21) to the pulling step (S22) are repeated until it is determined that the number of repetitions n has been reached (Yes). . Thereby, a multi-layer hard coat film is formed.

<Second curing process (S24 ')>
In the determination step (S23) described above, in the second curing processing step (S24 ′) when it is determined that the number of repetitions n has been reached (Yes), the processing conditions differ from those in the first curing processing step (S24). The curing process is performed at Here, the coating liquid L applied to the surface of the lens substrate 1 in the previous lifting step (S22) is cured, and all the hard coat films including the already formed lower hard coat film are completely removed. A curing process is performed under the curing conditions.

  For this reason, in this 2nd hardening process process (S24 '), when resin used as the main ingredient of a hard-coat film is a thermosetting resin, for example, it is higher temperature and length than 1st hardening process (S24). Heat treatment is performed under at least one of the treatment conditions for a period of time. In the case of a photocurable resin, a curing process is performed in which the amount of light irradiation is increased, the heating performed as necessary is increased, or the processing time is extended as compared with the first curing process (S24). Just do it.

  As an example of such a second curing process (S24 '), for example, a two-stage curing process is performed.

  In the first stage, as in the previous lifting step (S22), the lens surface 1a is held substantially perpendicular to the liquid surface PL of the coating liquid L, and the upper end P1 and the lower end P2 of the lens substrate 1 are Maintain the vertical relationship. That is, the lens base material 1 is not turned upside down from the dipping step (S21) to the first stage of the second curing process (S24 ′), and is set in the first dipping step (S21). The vertical relationship between the upper end P1 and the lower end P2 is maintained. In this first stage, the coating liquid L may be cured to such an extent that fluidity is lost, and a curing process may be performed under the same processing conditions as in the first curing process step (S24).

  In the second stage thereafter, in order to completely cure all the hard coat films including the lower layer hard coat film already formed together with the coating liquid L applied last, the light irradiation amount is increased or the heating temperature is increased. Is subjected to additional curing. At this time, it is not necessary to keep the lens surface 1a of the lens substrate 1 vertical, and the lens substrate 1 may be removed from the holding member 3 and placed flat.

  As described above, the thick hard coat film (optical film) is formed by the dipping method (immersion method) in which the pulling process is repeated a plurality of times.

<< Antireflection Film Formation S3 >>
Next, an antireflection film is formed on the hard coat film (S3). The antireflection film formed here may be either an inorganic material or an organic material. When the lens substrate 1 is made of a high refractive index material, any material that does not affect its optical characteristics may be used.

  Such an antireflection film is formed by a vacuum deposition method or the like if an inorganic material is used, and applied by a dipping method or a spin coating method if an organic material is used, and then heated or irradiated with light. It can be formed by curing by irradiation or the like.

  As described above, as shown in FIG. 5, an optical lens 17 in which the primer layer 11, the hard coat film 13, and the antireflection film 15 are provided in this order on the lens substrate 1 is obtained.

<< Effects of Manufacturing Method of Embodiment >>
According to the manufacturing method as described above, in the formation of the hard coat film 13 to which the dipping method is applied (S2), the pulling process (S22) for lifting the lens base material 1 from the coating liquid L is performed during the pulling period. It was found that by providing a period during which the speed is reduced, a hard coat film 13 having a uniform film thickness can be obtained within the lens surface 1a, as will be described in a later example. Then, by repeatedly performing such a pulling step (S22) across the first curing process step (S24), the hard coat film 13 with high in-plane uniformity is overcoated, and the uniformity of the film thickness is increased. It is possible to increase the thickness of the high hard coat film 13.

  As a result, it is possible to form the hard coat film 13 having a uniform film thickness distribution on the lens substrate 1 while being a thick film. As a result, the hard coating film 13 having a large film thickness can improve the scratch resistance of the optical lens 17. Moreover, although the hard coat film 13 has a large film thickness, the in-plane uniformity of the film thickness is good, so that no interference fringes are generated.

  In the repeated pulling step (S22), the lens substrate 1 is pulled up from the coating liquid L with the same one end set at the periphery of the lens substrate 1 as the upper end P1. Thereby, dripping from the holding member 3 that holds the lens substrate 1 is prevented, and a hard coat film 13 having a uniform film thickness is obtained on the entire surface extending to the periphery of the lens substrate 1. Moreover, since the process of reversing the lens substrate 1 upside down is not included in the repeated steps, non-uniformity and dust generation due to holding by the holding member 3 can be avoided.

  Further, in each lifting step (S22), at least immediately after the lens substrate 1 starts to be exposed from the coating liquid L (the first half of the lifting period) and immediately before the lens substrate 1 finishes the exposure (the second half of the lifting period). On the other hand, when a constant speed period with a constant lens substrate pulling rate is provided, the in-plane uniformity of the film thickness of the hard coat film 13 can be improved as will be described in a later example.

  In the second curing process (S24 ′) after it has been determined that the pulling process (S22) has been performed a predetermined number of times n, that is, the hard coat film 13 has reached a predetermined film thickness, the coating liquid is completely removed. In order to cure, the curing process is performed under conditions different from those in the first process step (S24). Thereby, in the first curing process (S24), the hard coat film is not completely cured, and in the second curing process (S24 '), the hard coat film of all layers repeatedly applied before then. The cross-linking reaction between the layers 13 progresses, and a hard coat film 13 without a boundary between repeated coating layers can be formed.

  In the above-described embodiment, the procedure in which the present invention is applied when the hard coat film 13 is formed on the lens substrate 1 has been described. However, the present invention is not limited to application to the formation of the hard coat film 13, and can be widely applied to the formation of optical films that can be formed by the dipping method. For example, the present invention can be applied when the antireflection film 15 is formed of an organic material. In this case, a plurality of types of coating liquids containing materials having different refractive indexes are prepared, the coating liquid is exchanged for each immersion process to the curing treatment process, and the coating liquid is completely cured in each curing treatment process. The processing may be terminated when the number of times is repeated. Thereby, the antireflection film 15 in which the uniformity of the film thickness is ensured in the lens surface can be formed by the dipping method.

≪Preparation of hard coat liquid (coating liquid) ≫
In an atmosphere at a temperature condition of 5 ° C. in the refrigerator, a material containing particulate tin oxide (SnO ₂ ) was put into the first container as a material containing a metal oxide. As this material, a sol-like material (tin oxide sol) in which 30% by weight of a trade name HIS-30MH manufactured by Nissan Chemical Industries, Ltd. was dispersed in methanol was used.

An organosilicon compound was added to the tin oxide sol in the first container. As an organosilicon compound, γ-GPS (γ-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM403) was added to start stirring, and stirring was continued. Further, 10 ⁻³ N hydrochloric acid was dropped into the first container, and stirring was continued in a refrigerator at 5 ° C.

  Next, a leveling solution was prepared. At this time, the leveling agent (product name: Y7006, manufactured by Toray Dow Corning Co., Ltd.) is removed with a solvent (methoxypropanol propylene glycol monomethyl ether: PGM) in the second container under an atmosphere of 5 ° C. in the refrigerator. Dilution and stirring were made into a leveling solution and stored in a refrigerator at 5 ° C.

  When the tin oxide sol in the first container was stirred for 2 days, PGM was continuously charged into the first container, and stirring was further continued for 1 day. Then, the leveling solution in the second container is put into the first container, and then a curing agent (aluminum acetylacetonate, manufactured by Dojin Chemical Laboratory, trade name Dotite Al-AA) is further added. Stirring was continued. The above materials were gradually hydrolyzed over an appropriate time (for example, 3 to 14 days, 8 days in this example) to prepare a hard coat solution as a coating solution.

The mixing ratio (% by weight) of each material in the hard coat solution produced as described above is as follows.
Tin oxide sol: 45.54%, γ-GPS: 15.0%, hydrochloric acid (10 ⁻³ normal): 2.4%, water: 3.45%, leveling agent: 0.06%, PGM: 33.3 %, Curing agent: 0.25%.

<Evaluation of the produced hard coat solution>
As a result of liquid evaluation of this hard coat liquid, the specific gravity was 1.1, the viscosity was 3.0 mPa · s, and the refractive index was 1.59.

≪Hard coat film formation≫
Using the hard coat liquid prepared as described above, a hard coat film was formed by the dipping method with the number of repetitions n = 1. Here, a plastic lens (manufactured by HOYA Corporation, refractive index 1.67, lens power S-4.00, lens diameter 75 mm) was used as the lens substrate.

  The pulling speed in the pulling process of the lens base material from the hard coat liquid was performed under three conditions of pulling speed conditions 1 to 3. Among these, the pulling speed conditions 1 and 2 are the same as the conditions described with reference to FIG. 4, and a deceleration period is provided in the pulling period. On the other hand, in the pulling speed condition 3, the pulling speed within the pulling period is constant at 360 mm / min. Table 1 below shows the setting of the lifting speed for each distance from the upper end P1 of the lens substrate 1 to the liquid surface PL (distance from the upper end of the lens) during the pulling period of the pulling speed conditions 1 to 3 employed here. Indicates the value.

  In the curing process after the pulling process, the lens substrate was kept in a substantially vertical state, and a thermosetting process was performed at a heating temperature of 105 ° C. for 1 hour.

<Evaluation of formed hard coat film>
1. Measurement of Hard Coat Film Thickness of the reflection spectrum of the lens substrate on which one hard coat film is formed is measured with a spectrophotometer (USPM-RU made by Olympus), and the measured reflection spectrum and hard coat film are measured. The film thickness of the hard coat film was calculated from the refractive index. Here, in order to confirm the film thickness distribution, the film thickness was measured at three points: the upper part, the center, and the lower part of the lens substrate in the pulling process. The upper part of the lens substrate was positioned 30 mm upward from the center of the lens, and the lower part of the lens substrate was positioned 30 mm downward from the center of the lens.

2. Interference fringes With the concave surface of the lens on which the hard coat film is formed facing upward, with the three-wavelength fluorescent lamp installed at a position spaced 50 cm away from the lens surface, the concave surface of the lens surface from an angle of 45 degrees forward and diagonally It is possible to clearly observe the interference fringes, and the number of interference fringes was counted in this state.

  The above results are shown in Table 2 below.

  As shown in Table 2, in the pulling process of pulling up the lens substrate from the hard coat liquid (coating liquid), a hard coat film formed by employing pulling speed conditions 1 and 2 in which a deceleration period is provided within the pulling period It was confirmed that the film thickness was uniform in each part in the pulling direction. In addition, no interference fringes were observed.

  On the other hand, it was confirmed that the thickness of the hard coat film formed by adopting the pulling speed condition 3 in which the pulling speed during the pulling period is constant is large in the lower part in the pulling direction and the film thickness varies greatly. It was done. In addition, nine interference fringes were generated due to variations in film thickness.

<< Production of optical lens >>
As Examples 1 and 2 and Comparative Examples 1 to 4, using the hard coat liquid produced as described above, optical lenses were produced according to the procedure described above using the flowchart of FIG. Here, a plastic lens (manufactured by HOYA Corporation, refractive index 1.67, lens power S-4.00, lens diameter 75 mm) was used as the lens substrate.

[Formation of primer layer (S1)]
In Examples 1 and 2 and Comparative Examples 1 to 4, the primer layer was formed using the dipping method. As the primer solution, a product obtained by adding 0.06% of a leveling agent Y7006 to a product obtained by diluting 6 times the product name Adekabon titer HUX-232 manufactured by ADEKA Corporation with PGM was used.

[Formation of hard coat film (S2)]
In Examples 1 and 2 and Comparative Examples 1 to 4, a hard coat film was formed as follows.

<Immersion process (S21)>
In Examples 1 and 2 and Comparative Examples 1 to 4, the previously prepared hard coat solution was used as the coating solution.

<Pulling up process (S22) and judging process (S23)>
Example 1 Pull-up speed condition 1 shown in Table 1 above, number of repetitions n = 8, no inversion.
Example 2 Pull-up speed condition 2 shown in Table 1 above, number of repetitions n = 8, no reversal.
Comparative Example 1 ... Pulling speed condition 3 shown in Table 1 above, number of repetitions n = 2, no inversion.
Comparative example 2 ... Pulling speed condition 3 shown in Table 1 above, number of repetitions n = 4, no inversion.
Comparative Example 3 ... Pulling speed condition 3 shown in Table 1 above, number of repetitions n = 8, no inversion.
Comparative Example 4 ... Pulling speed condition 3 shown in Table 1 above, number of repetitions n = 8 times, with inversion. In Comparative Example 4, after the next curing treatment step (S24), the upper end P1 and the lower end P2 of the lens substrate were reversed and returned to the next immersion step (S21). When reversing the lens substrate, the lens substrate was removed from the holding member, then the lens substrate was reversed, and then the lens substrate was re-fixed to the holding member.

<First curing process (S24)>
In Examples 1 and 2 and Comparative Examples 1 to 4, thermosetting treatment was performed at 75 ° C. for 20 minutes.

<Second curing process (S24 ')>
In Examples 1 and 2 and Comparative Examples 1 to 4, a thermosetting treatment at 105 ° C. for 1 hour was performed.

[Formation of Antireflection Film (S3)]
In Examples 1 and 2 and Comparative Examples 1 to 4, antireflection films in which silicon oxide (SiO ₂ ) films and tantalum oxide (Ta ₂ O ₅ ) films were alternately stacked were formed by vacuum deposition.

<Evaluation of the produced optical lens>
1. Measurement of Hard Coat Film Thickness After the hard coat film is formed, the reflection spectrum is measured with a spectrophotometer (Olympus USPM-RU) for the lens substrate formed up to the hard coat film before the antireflection film is formed. The film thickness was calculated from the measured spectrum and the refractive index of the hard coat film. Here, in order to confirm the film thickness distribution, the film thickness was measured at three points: the upper part, the center, and the lower part of the lens substrate in the pulling process. The upper part of the lens substrate was positioned 30 mm upward from the center of the lens, and the lower part of the lens substrate was positioned 30 mm downward from the center of the lens.

2. Interference fringes With the concave surface side of the optical lens formed up to the antireflection film facing upward and a three-wavelength fluorescent lamp installed at a position spaced 50 cm away from the lens surface, the lens surface is tilted from an angle of 45 degrees forward and obliquely. The number of interference fringes was counted by observing the concave surface. Three interference fringes within a lens having a diameter of 75 mm were made inconspicuous and acceptable, and three or less interference fringes were accepted.

3. Dripping We determined the presence or absence of dripping by observing the concave surface of the lens surface in the same manner as the evaluation of interference fringes. When the liquid dripping from the trace of the holding member occurred with a length of 3 mm or more, the determination was “failed”.

  1 above. ~ 3. The evaluation results are shown in Table 3 below.

  As shown in Table 3, the hard coat film formed in Examples 1 and 2, that is, in the pulling process (S22), was formed by employing pulling speed conditions 1 and 2 in which a deceleration period was provided within the pulling period. The hard coat film had a uniform thickness at each part in the pulling direction, and no interference fringes were observed. Thus, by applying the present invention that repeats film formation by a dipping method with a deceleration period within the pulling period, a hard coat film with a uniform thickness distribution in the lens surface and suppressed interference fringes can be obtained. It was confirmed that it can be formed into a film.

  Furthermore, the film thickness of Example 1 was smaller than that of Example 2. From this result, it was confirmed that the film thickness of the hard coat film can be controlled not only by the number of repetitions of the dipping method but also by setting the pulling speed condition in the pulling process.

  In addition, no dripping occurred in the hard coat films formed in Examples 1 and 2, that is, the hard coat films formed by repeating the pulling step (S22) without inverting the substrate.

  On the other hand, in Comparative Examples 1 to 3 in which no deceleration period is provided during the pulling period (constant pulling speed, no reversal), the difference in film thickness is large between the top and bottom of the lens base material, and interference fringes are suppressed. It wasn't done. From the results of Comparative Examples 1 to 3, it can be seen that as the number of pulling times n increases, the difference in film thickness between the upper and lower surfaces of the lens substrate increases, and the number of interference fringes and the number of interference fringes also increase. Accordingly, when dipping is repeated a plurality of times without causing dripping, a hard coat film having a small film thickness distribution is obtained by performing a pull-up with a deceleration period in each pull-up step (S22). It can be seen that it is important to form each layer.

  Further, in Comparative Example 4 (with a constant pulling speed and with reversal), the lens base material is turned upside down so that the film thickness distribution is small and interference fringes can be suppressed. Has occurred. In Comparative Example 4, the lifting speed condition 3 (a constant speed of 360 mm / min) is applied, and the time required for the entire pulling period is shorter than the lifting speed conditions 1 and 2 of Examples 1 and 2. For this reason, although the film thickness distribution was small, the film thickness was larger than that of Example 1.

  DESCRIPTION OF SYMBOLS 1 ... Lens base material, 13 ... Hard coat film | membrane, 17 ... Optical lens, L ... Coating liquid

Claims (5)

An immersion step of immersing the lens substrate in the coating solution;
From the start of exposure of the lens substrate from the coating solution until it is completely exposed, a lifting step of raising the lens substrate from the coating solution by providing a period for reducing the lifting speed;
A curing process for curing the coating liquid applied to the surface of the lens substrate to form a hard coat film; and
An optical lens manufacturing method comprising: a determination step of determining that the dipping step, the pulling step, and the curing treatment step are repeated a plurality of times until the hard coat film has a predetermined thickness. The method of manufacturing an optical lens according to claim 1, wherein the dipping step, the pulling step, and the curing treatment step are performed in a state in which a lens surface of the lens substrate is held substantially vertically. The method for manufacturing an optical lens according to claim 1, wherein in the repeated pulling step, the lens base is lifted with the same one end set on the periphery of the lens base as an upper end. 2. The pulling-up speed of the lens base material is made constant in at least one of immediately after the lens base material starts exposure from the coating liquid and immediately before the lens base material ends exposure in the lifting step. The manufacturing method of the optical lens in any one of -3. The determination step is performed between the pulling step and the curing treatment step,
2. In the curing process step after it is determined in the determination step that the hard coat film has reached a predetermined film thickness, a curing process is performed under conditions different from the previous time in order to completely cure the coating liquid. The manufacturing method of the optical lens in any one of -4.

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