Patent Publication Number: US-2022219361-A1

Title: Injection molding apparatus, injection molding method and production method of molded product using injection molding apparatus, and laminated lens

Description:
TECHNICAL FIELD 
     The present invention relates to an injection molding apparatus, an injection molding method and a production method of a molded product using the injection molding apparatus, and a laminated lens 
     BACKGROUND ART 
     Examples of a method of obtaining a molded product by polymerizing a composition containing a polymerizable compound include a casting polymerization method and the like. In the casting polymerization method, an injection molding apparatus including a unit which fixes peripheral portions of two mold substrates by a fixing member in a state in which the two mold substrates face each other, and injects the composition into a space of the two mold substrates is generally used. Then, the molded product is obtained by a method of injecting the composition into the space and then polymerizing and curing the composition. 
     Patent Document 1 discloses a casting mold for lens molding, which is formed by providing a liquid reservoir unit which connects with a molding space between a mold and a gasket. It is disclosed that, as a result, it is possible to compensate a volume change in the molding space with an optical material of the liquid reservoir unit. 
     Patent Documents 2 and 3 disclose a technique in which a gasket (fixing member) having a special shape is used. It is disclosed that, as a result, an influence on a lens during a polymerization process is alleviated. 
     Patent Document 4 discloses a molding apparatus that produces a polarizing lens. Patent Document 4 discloses that a gap between a polarizing film and a mold is about 2 to 5 mm. 
     RELATED DOCUMENTS 
     Patent Documents 
     [Patent Document 1] Japanese Unexamined Patent Publication No. H1-258916 
     [Patent Document 2] Japanese Unexamined Patent Publication No. H9-254170 
     [Patent Document 3] Japanese Unexamined Patent Publication No. 2006-205710 
     [Patent Document 4] Japanese Unexamined Patent Publication No. 2018-72851 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     However, in the related art, in a case in which a width of the gap formed between two mold substrates is narrow, it is difficult to homogeneously fill the gap with the composition, and mixing of air bubbles and the like may be observed in the molded product. In particular, in a case in which the viscosity of the composition is high, the above tendency is remarkable. 
     Solution to Problem 
     As a result of diligent studies, the present inventors have found that a gap is homogeneously filled with a composition by providing a space at a periphery of the gap formed between two mold substrates, and completed the present invention. 
     That is, the present invention can be shown as follows. 
     [1] An injection molding apparatus including a substantially circular first substrate, a substantially circular second substrate disposed to face a surface of the first substrate, a fixing member which fixes a peripheral end portion of the first substrate and a peripheral end portion of the second substrate, and an injection portion which is provided in the fixing member and from which a composition is injected into a gap between the first substrate and the second substrate, in which a space connecting with the injection portion and the gap is provided in at least a part of a periphery of the gap, and a width of the space in a thickness direction is larger than a width of the gap in the thickness direction. 
     [2] The injection molding apparatus according to [1], in which the space is provided over a substantially half of a circumference of the periphery of the gap. 
     [3] The injection molding apparatus according to [1], in which the space is provided over an entire periphery of the gap. 
     [4] The injection molding apparatus according to anyone of [1] to [3], in which the width of the gap in the thickness direction is substantially the same. 
     [5] The injection molding apparatus according to anyone of [1] to [4], in which the width of the gap in the thickness direction is 0.05 to 2 mm. 
     [6] The injection molding apparatus according to anyone of [1] to [5], in which the first substrate is a mold substrate having a forming surface for forming an objective surface of a lens, which is located on a second substrate side, and the second substrate is a resin substrate. 
     [7] The injection molding apparatus according to anyone of [1] to [5], in which the first substrate and the second substrate are mold substrates. 
     [8] The injection molding apparatus according to anyone of [1] to [7], in which a notch is provided in at least one of a periphery of the first substrate and a periphery of the second substrate, and the notch forms the space. 
     [9] The injection molding apparatus according to anyone of [1] to [6], in which the second substrate is a resin substrate, a notch is provided over an entire circumference of a periphery of the second substrate, and the notch forms the space. 
     [10] The injection molding apparatus according to any one of [1] to [7], in which the surface of the first substrate is a curved surface, the gap is provided between the surface and a curved surface of the second substrate facing the surface, at least one of the curved surface of the first substrate and the curved surface of the second substrate has a radius of curvature of at least a part of the curved surface of a periphery thereof smaller than a radius of curvature of the curved surface surrounded by the periphery, and the space is formed in at least a part of the periphery of the gap. 
     [11] The injection molding apparatus according to any one of [1] to [7], in which the second substrate is a resin substrate, the surface of the first substrate is a curved surface, the gap is provided between the surface and a curved surface of the second substrate facing the surface, a radius of curvature of an entire circumference of a periphery of the second substrate is smaller than a radius of curvature of the curved surface surrounded by the periphery, and the space is formed in the periphery of the gap. 
     [12] The injection molding apparatus according to any one of [1] to [11], in which the fixing member is a tape or a gasket. 
     [13] An injection molding method of a composition, in which the injection molding apparatus according to any one of [1] to [12] is disposed such that the injection portion is positioned above, and the injection molding method includes a step of injecting the composition from the injection portion into the space, and a step of filling the gap with the composition through the space. 
     [14] The injection molding method of a composition according to [13], in which in the step of injecting the composition, a viscosity of the composition is 5 to 1000 mPa·s. 
     [15] The injection molding method according to [13] or [14], in which the second substrate is a resin substrate, the resin substrate is a thiourethane resin consisting of an isocyanate compound and a thiol compound, and the composition includes the isocyanate compound and the thiol compound, 
     in which the isocyanate compound is at least one selected from xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate, and 
     in which the thiol compound is at least one selected from the group consisting of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, and pentaerythritol tetrakis(3-mercaptopropionate). 
     [16] The injection molding method according to [15], in which the isocyanate compound and the thiol compound constituting the resin substrate are the same as the isocyanate compound and the thiol compound contained in the composition, respectively. 
     [17] A production method of a molded product, in which the injection molding apparatus according to any one of [1] to [12] is disposed such that the injection portion is positioned above, and the production method includes a step of injecting the composition from the injection portion into the space, a step of filling the gap with the composition through the space, and a step of curing the composition. 
     [18] The production method of a molded product according to [17], in which in the step of injecting the composition, a viscosity of the composition is 5 to 1000 mPa·s. 
     [19] The production method of a molded product according to [17] or [18], in which the second substrate is a resin substrate, the resin substrate is a thiourethane resin consisting of an isocyanate compound and a thiol compound, and the composition includes the isocyanate compound and the thiol compound, 
     in which the isocyanate compound is at least one selected from xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate, and 
     in which the thiol compound is at least one selected from the group consisting of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, and pentaerythritol tetrakis(3-mercaptopropionate). 
     [20] The production method of a molded product according to [19], in which the isocyanate compound and the thiol compound constituting the resin substrate are the same as the isocyanate compound and the thiol compound contained in the composition, respectively. 
     [21] A laminated lens including a first resin layer having an objective surface, and a second resin layer, in which a thickness of at least a part of a periphery of the first resin layer is thicker than a thickness of a portion surrounded by the periphery. 
     [22] The laminated lens according to [21], in which the thickness of the portion surrounded by the periphery of the first resin layer is substantially the same. 
     In the present invention, the substantially circular shape (circular shape) encompasses from a perfect circular shape to an elliptical shape. 
     Advantageous Effects of Invention 
     With the injection molding apparatus according to the present invention, it is possible to homogeneously fill a gap having a narrow width in a thickness direction, which is formed between two substrates, even with a composition having a high viscosity, and it is possible to produce a molded product having excellent appearance in which mixing of air bubbles and the like are suppressed with good yield. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional view schematically showing an injection molding apparatus according to a first embodiment. 
         FIG. 2  is a schematic plan view schematically showing the injection molding apparatus according to the first embodiment. 
         FIG. 3  is a schematic plan view schematically showing another aspect of a space shape in the injection molding apparatus according to the first embodiment. 
         FIG. 4  is an enlarged cross-sectional view schematically showing another aspect of a space cross section in the injection molding apparatus according to the first embodiment. 
         FIG. 5  is an enlarged cross-sectional view schematically showing still another aspect of the space cross section in the injection molding apparatus according to the first embodiment. 
         FIG. 6  is a schematic cross-sectional view schematically showing an injection molding apparatus according to a second embodiment. 
         FIG. 7  is a schematic cross-sectional view of a laminated lens according to the present embodiment. 
         FIG. 8  is a schematic cross-sectional view schematically showing an injection molding apparatus used in a comparative example. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an injection molding apparatus according to the present invention will be described. 
     [Injection Molding Apparatus] 
     The injection molding apparatus according to the present invention includes a substantially circular first substrate, a substantially circular second substrate disposed to face a surface of the first substrate, a fixing member which fixes a peripheral end portion of the first substrate and a peripheral end portion of the second substrate, and an injection portion which is provided in the fixing member and from which a composition is injected into a gap between the first substrate and the second substrate. 
     A space connecting with the injection portion and the gap is provided in at least a part of a periphery of the gap, and a width of the space in a thickness direction is larger than a width of the gap in the thickness direction. The space need only be formed on at least a part of the periphery of the gap, but from the viewpoint of the effect of the present invention, it is preferable that the space be provided over a substantially half of a circumference of the periphery or be provided over an entire periphery of the gap. 
     As described above, with the injection molding apparatus according to the present invention, it is possible to homogeneously fill a gap having a narrow width, which is formed between the first substrate and the second substrate, even with a composition having a high viscosity, and it is possible to produce a molded product having excellent appearance in which mixing of air bubbles and the like are suppressed with good yield. Further, in a case in which the obtained molded product is used as an optical material, it is possible to produce an optical material having excellent appearance in which mixing of air bubbles or a stria is suppressed with good yield. 
     An embodiment of the injection molding apparatus according to the present invention will be described, by a first embodiment or a second embodiment, with reference to the accompanying drawings. Note that the same reference numerals will not be repeated as appropriate. In the present embodiment, “to” represents “larger than or equal to” to “less than or equal to” unless otherwise specified. 
     First Embodiment 
     As shown in a schematic cross-sectional view of  FIG. 1 , an injection molding apparatus  10  according to the present embodiment includes a substantially circular first substrate  12 , a substantially circular second substrate  14  disposed to face a surface  12   a  of the first substrate  12 , a fixing member  16  which fixes a peripheral end portion of the first substrate  12  and a peripheral end portion of the second substrate  14 , and an injection portion  18  which is provided in the fixing member  16  and from which a composition is injected into a gap  20  between the first substrate  12  and the second substrate  14 . A space  22  is provided over an entire periphery of the gap  20 . 
     The substantially circular first substrate  12  is not particularly limited as long as the molded product can be prepared in the gap  20 , but can be made of, for example, glass, metal, resin, or the like. The substantially circular first substrate  12  can be used as a mold substrate, and can also be a laminated body of a thin film-shaped molded product formed in the gap  20  and the first substrate  12 . The first substrate  12  has the surface  12   a  facing the second substrate  14 . In a case in which the molded product is used as a laminated film of an optical lens, the surface  12   a  can be a forming surface on which an objective surface is formed. 
     The substantially circular second substrate  14  is not particularly limited as long as the molded product can be prepared in the gap  20 , but can be made of glass, metal, resin, or the like. The substantially circular second substrate  14  can be used as a mold substrate, can also be a laminated body of a thin film-shaped molded product formed in the gap  20  and the second substrate  14 , and can be a laminated body of the first substrate  12 , a thin film-shaped molded product, and the second substrate  14 . 
     The substantially circular second substrate  14  has a surface  14   a  facing the surface  12   a  of the first substrate  12 , and the first substrate  12  and the second substrate  14  are curved in the same direction. A radius of curvature of the surface (curved surface)  12   a  and the surface (curved surface)  14   a  are substantially the same, and a width of the gap  20  between these surfaces in the thickness direction is substantially the same. The width of the gap  20  in the thickness direction is 0.05 to 2 mm, preferably 0.1 to 1.0 mm, and more preferably 0.1 to 0.6 mm. 
     With the injection molding apparatus  10  according to the present embodiment, even in a case of the gap  20  having a narrow width as described above, it is possible to homogeneously fill the gap  20  with the composition through the space  22 , and it is possible to produce the molded product having excellent appearance in which mixing of air bubbles and the like are suppressed with good yield. 
     The second substrate  14  has a notch  24  over an entire circumference of the periphery thereof. As shown in  FIG. 1 , the injection molding apparatus  10  includes the space  22  surrounded by the notch  24  of the second substrate  14 , the first substrate  12 , and the fixing member  16 . A width i of the space  22  in a substrate thickness direction is not particularly limited as long as the width i is larger than the width of the gap  20 , and it is possible to appropriately change an upper limit value depending on the thickness, strength, or the like of the second substrate  14 . For example, it is preferable that the width i of the space  22  in a substrate diameter direction be about 1 to 10 mm. 
     A width ii of the space  22  in the substrate diameter direction is not particularly limited as long as the space  22  is formed, but is preferably about 1 to 10 mm. 
     A diameter iii of the second substrate  14  is about 50 mm to 100 mm. 
     A ratio (ii/iii) of the width ii of the space  22  in the substrate diameter direction to the diameter iii of the second substrate  14  exceeds 0 and equal to or less than 0.27, preferably about 0.01 to 0.27. 
     As shown in  FIG. 1 , the space  22  connects with the injection portion  18  and the gap  20 , and as shown in a schematic plan view of  FIG. 2 , a configuration is adopted in which it is possible to fill the gap  20  with the composition injected from the injection portion  18  through the space  22 . 
     In the present embodiment, the first substrate  12  and the second substrate  14  can be the mold substrates. In a case in which the thin film-shaped molded product formed in the gap  20  is used as the laminated film of the optical lens, the first substrate  12  is the mold substrate having the forming surface (surface  12   a ) for forming the objective surface of a lens, which is located on the second substrate  14  side, and the second substrate  14  can be a resin substrate. 
     Examples of a monomer component constituting the resin substrate, which is the second substrate  14 , include a monomer component contained in the composition described below, and these monomer components may be the same or different. 
     The fixing member  16  is not particularly limited as long as the surface  12   a  of the first substrate  12  and the surface  14   a  of the second substrate  14  can be disposed to face each other, but the fixing member  16  can be a tape, a gasket, or the like. By winding the peripheral end portion of the first substrate  12  and the peripheral end portion of the second substrate  14  by the tape, the positions thereof can be fixed. 
     The injection portion  18  (not shown) is provided in the fixing member  16  such that the composition can be injected into the space  22 . Examples thereof include an opening portion, a joint of an injection device, and the like. The composition can be injected from the injection portion  18  into the space  22 , and an injection unit such as a pipette tip, a syringe, or an automatic injection device can be connected to the injection portion  18 . 
     The viscosity of the composition used in the present embodiment can be 5 to 1000 mPa·s, preferably 10 to 500 mPa·s. 
     With the injection molding apparatus  10  according to the present embodiment, even in a case of the composition having the viscosity as described above, it is possible to homogeneously fill the gap  20  with the composition through the space  22 , and it is possible to produce the molded product having excellent appearance in which mixing of the air bubbles and the like are suppressed with good yield. 
     The monomer components and the like constituting the composition will be described below. 
     Although the embodiment of the present invention has been described above, the embodiment is an example of the present invention, and it is possible to adopt various configurations other than the above as long as the effects of the present invention are not impaired. 
     In  FIG. 1 , the example has been described in which the space  22  is formed by being surrounded by the notch  24  of the second substrate  14 , the first substrate  12 , and the fixing member  16 . However, a groove having a U-shaped cross section may be provided over the entire circumference of the periphery of the second substrate  14 , and the space  22  may be formed by the groove formed in the second substrate  14  and the first substrate  12 . 
     In  FIG. 1 , the example has been described in which the surface  12   a  of the first substrate  12  is a concave surface and the surface  14   a  of the second substrate  14  is a convex surface. However, the surface  12   a  may be a convex surface and the surface  14   a  may be a concave surface. 
     In  FIG. 1 , the example has been described in which the first substrate  12  and the second substrate  14  are curved. However, it is possible to adopt various shapes for the molded product depending on the application, and for example, both the first substrate  12  and the second substrate  14  may also be a substantially circular flat plate. That is, as the resin substrate, which is the second substrate  14 , there is a resin lens on which both surfaces are the curved surfaces, a resin lens on which only surface  14   a  is the curved surface, or a resin flat plate on which both surfaces are flat surfaces. The same applies to another embodiment. 
     In  FIG. 1 , the example has been described in which the space  22  is provided over the entire circumference of the periphery of the second substrate  14 . However, as shown in  FIG. 3 , the space  22  may be provided over a substantially half of the circumference of the periphery of the second substrate  14  and may be provided over any position selected from a substantially half of the circumference (½) to less than the entire circumference. 
     As shown in  FIG. 4 , the notch  24  may be provided on the periphery of the first substrate  12  to form the space  22 , and as shown in FIG.  5 , the notch  24  may be provided on the peripheries of the first substrate  12  and the second substrate  14  to form the space  22 . Further, the notches  24  may be provided alternately on the first substrate  12  and the second substrate  14  in a circumferential direction. 
     Second Embodiment 
     As shown in a schematic cross-sectional view of  FIG. 6 , the injection molding apparatus  10  according to the present embodiment includes the substantially circular first substrate  12 , a substantially circular second substrate  15  disposed to face the surface  12   a  of the first substrate  12 , the fixing member  16  which fixes the peripheral end portion of the first substrate  12  and a peripheral end portion of the second substrate  15 , and the injection portion  18  which is provided in the fixing member  16  and from which the composition is injected into a gap  20  between the first substrate  12  and the second substrate  15 . 
     The gap  20  is provided between the curved surface  12   a  of the first substrate  12  and a curved surface  15   a  of the second substrate  15  facing the curved surface  12   a , and a radius of curvature b of a curved surface  15   b  of a periphery of the curved surface  15   a  of the second substrate  15  is smaller than a radius of curvature a of the curved surface  15   a  surrounded by the periphery. As a result, a space  23  is formed on the periphery of the gap  20 . 
     The substantially circular first substrate  12 , the surface  12   a , and the injection portion  18  (not shown) are the same as those in the first embodiment, and the description thereof will not be repeated. 
     The substantially circular second substrate  15  is not particularly limited as long as the molded product can be prepared in the gap  20 , but can be made of glass, metal, resin, or the like. The substantially circular second substrate  15  can be used as a mold substrate, can also be a laminated body of a thin film-shaped molded product formed in the gap  20  and the second substrate  15 , and can be a laminated body of the first substrate  12 , a thin film-shaped molded product, and the second substrate  15 . 
     The substantially circular second substrate  15  has a surface  15   a  facing the surface  12   a  of the first substrate  12 , and the first substrate  12  and the second substrate  15  are curved in the same direction. A radius of curvature of the surface (curved surface)  12   a  and the surface (curved surface)  15   a  are substantially the same, and a width of the gap  20  between these surfaces in the thickness direction is substantially the same. The width of the gap  20  in the thickness direction is 0.05 to 2 mm, preferably 0.1 to 1.0 mm, and more preferably 0.1 to 0.6 mm. 
     The second substrate  15  has the curved surface  15   a  and the curved surface  15   b  on the peripheral portion extending over the entire circumference. The radius of curvature b of the curved surface  15   b  on the surface periphery is different from the radius of curvature a of the curved surface  15   a  surrounded by the curved surface  15   b , and the radius of curvature b is smaller than the radius of curvature a. As a result, a width c of the second substrate  15  on the curved surface  15   a  in the thickness direction is larger than a width d of the second substrate  15  on the curved surface  15   b  of the peripheral portion in the thickness direction. Since the radius of curvature of the surface  12   a  of the first substrate  12  is fixed, the space  23  is formed on the periphery of the gap  20 . 
     The radius of curvature b of the curved surface  15   b  is not particularly limited as long as the radius of curvature b is smaller than the radius of curvature a of the curved surface  15   a  surrounded by the curved surface  15   b , but the radius of curvature a can be preferably 100 mm to 500 mm and more preferably 150 mm to 300 mm, and the radius of curvature b can be preferably 10 mm to 100 mm and more preferably 15 mm to 50 mm. 
     A width ii of the peripheral portion provided with the curved surface  15   b  in the substrate diameter direction is not particularly limited as long as the space  23  is formed, but is preferably about 1 to 10 mm. 
     A diameter iii of the second substrate  15  is about 50 mm to 100 mm. 
     A ratio (ii/iii) of the width ii of the peripheral portion provided with the curved surface  15   a  in the substrate diameter direction to the diameter iii of the second substrate  15  exceeds 0 and equal to or less than 0.27, preferably about 0.01 to 0.27. 
     With the injection molding apparatus  10  according to the present embodiment, even in a case of the gap  20  having a narrow width as described above, it is possible to homogeneously fill the gap  20  with the composition through the space  23 , and it is possible to produce the molded product having excellent appearance in which mixing of the air bubbles and the like are suppressed with good yield. 
     As shown in  FIG. 6 , the space  23  connects with the injection portion  18  and the gap  20 , and as shown in a schematic plan view of  FIG. 2 , a configuration is adopted in which it is possible to fill the gap  20  with the composition injected from the injection portion  18  through the space  23 . 
     In the present embodiment, the first substrate  12  and the second substrate  15  can be the mold substrates. In a case in which the thin film-shaped molded product formed in the gap  20  is used as the laminated film of the optical lens, the first substrate  12  the mold substrate having the forming surface for forming the objective surface of a lens, which is located on the second substrate  15  side, and the second substrate  15  can be a resin substrate. 
     Examples of a monomer component constituting the resin substrate, which is the second substrate  15 , include a monomer component contained in the composition described below, and these monomer components may be the same or different. 
     The viscosity of the composition used in the present embodiment can be 5 to 1000 mPa·s, preferably 10 to 500 mPa·s. 
     With the injection molding apparatus  10  according to the present embodiment, even in a case of the composition having the viscosity as described above, it is possible to homogeneously fill the gap  20  with the composition through the space  23 , and it is possible to produce the molded product having excellent appearance in which mixing of the air bubbles and the like are suppressed with good yield. 
     The monomer components and the like constituting the composition will be described below. 
     Although the embodiment of the present invention has been described above, the embodiment is an example of the present invention, and it is possible to adopt various configurations other than the above as long as the effects of the present invention are not impaired. 
     In  FIG. 6 , the example has been described in which the space  23  is provided over the entire circumference of the periphery of the second substrate  15 . However, the space  23  may be provided over a substantially half of the circumference of the periphery of the second substrate  15  and may be provided over any position selected from a substantially half of the circumference (½) to less than the entire circumference. 
     In the present embodiment, the example has been described in which the surface  12   a  of the first substrate  12  is a curved flat plate having substantially the same radius of curvature on the entire surface, and the second substrate  15  has the curved surface  15   a  and the curved surface  15   b  on the peripheral portion extending over the entire circumference. However, it is possible to adopt a reversed configuration in which the entire surface of the second substrate  15  facing the first substrate  12  is a curved flat plate having substantially the same radius of curvature and the surface of the first substrate  12  facing the second substrate  15  is provided with the curved surface having a large radius of curvature on the peripheral portion thereof to form the space. 
     Further, the second substrate  15  may have the curved surface  15   b  on the peripheral portion, the first substrate  12  may have the curved surface on the peripheral portion, and the space  23  may be formed by the curved surfaces facing each other on the peripheral portion. Further, the curved surfaces of the peripheral portion may be provided alternately on the first substrate  12  and the second substrate  14  in a circumferential direction. 
     [Injection Molding Method and Production Method of Molded Product] 
     An injection molding method according to the present invention is provided in which the injection molding apparatus according to the present invention is disposed such that the injection portion is positioned above, and the injection molding method includes a step of injecting the composition from the injection portion into the space, and a step of filling the gap with the composition through the space. 
     In addition, a production method of the molded product according to the present invention further includes a step of curing the composition filled in the gap. 
     In the present embodiment, as will be described below, it is possible to add a functionality imparting agent such as a specific wavelength absorbing agent to the composition. Therefore, as compared with a case in which a film is attached to a front surface of a lens base material or a coat layer is formed, it is easy to optionally adjust an amount of addition thereof, and it is possible to increase the amount of addition depending on a functional design. Also, it is easy to add a plurality of functionality imparting agents, and a single layer can exhibit a plurality of functions as compared with a film or a coat layer. 
     Hereinafter, embodiments of the injection molding method and the production method of the molded product according to the present invention will be described in details with reference to the accompanying drawings. Note that the same reference numerals will not be repeated as appropriate. Note that although the description will be described by an example in which the injection molding apparatus  10  according to the first embodiment is used, the same can be performed in a case in which the injection molding apparatus  10  according to the second embodiment is used. 
     In the injection molding method according to the present embodiment, first, the injection molding apparatus  10  according to the present embodiment is disposed such that the injection portion  18  is positioned above in a vertical direction. Note that in order to prepare a polarizing lens, the resin substrate can be used as the second substrate  14 , and a polarizing film can be adhered to a front surface of the surface  14   a  in advance. 
     The polarizing film can be made of a thermoplastic resin. As the thermoplastic resin, there is a single layer such as thermoplastic polyester, thermoplastic polycarbonate, thermoplastic polyolefin, thermoplastic polyimide, thermoplastic polyamide, polyvinyl alcohol (PVA), or triacetyl cellulose (TAC), or a laminate of a plurality of layers of these resins. From the viewpoint of water resistance, heat resistance, and moldability, thermoplastic polyester and thermoplastic polycarbonate are preferable, and from the viewpoint of water resistance and weather resistance, thermoplastic polyester is more preferable. 
     Examples of the thermoplastic polyester include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, and polyethylene terephthalate is preferable from the viewpoint of water resistance, heat resistance, and moldability. 
     A dichroic dye or the like can be added to a functional layer made of the thermoplastic resin for the purpose of imparting polarization. A known dye is used as the dichroic dye. For example, the known dye is disclosed in Japanese Unexamined Patent Publication No. S61-087757, Japanese Unexamined Patent Publication No. S61-285259, Japanese Unexamined Patent Publication No. S62-270664, Japanese Unexamined Patent Publication No. S62-275163, Japanese Unexamined Patent Publication No. H1-103667, and the like. Specifically, there are anthraquinone-based, quinophthalone-based, and azo-based pigments. 
     Then, the composition is injected into the space  22  from the injection portion  18  by using an injection unit (not shown). An injection rate may be appropriately set depending on the viscosity of the composition and the like, and may be changed such that a filling rate in the space  22  is homogeneous. 
     As shown in the schematic plan view of  FIG. 2 , the composition injected into the space  22  is mainly moved downward in the space  22  and is moved into the gap  20  when reaching the lowermost portion. Since the gap  20  is mainly filled with the composition from the lower portion, it is possible to obtain the molded product having an excellent appearance in which mixing of the air bubbles and the like are suppressed, and since the gap  20  is homogeneously filled in a fixed direction, it is possible to obtain the molded product in which the generation of a stria is suppressed. 
     As the composition used in the present embodiment, there is a resin composition or a polymerizable composition. The resin is at least one selected from the group consisting of a polyester resin, a polycarbonate resin, a polyolefin resin, a poly(meth)acrylate resin, and a polysiloxane resin. 
     The polymerizable compound is at least one selected from a polyiso(thio)cyanate compound, a (thio)epoxy compound, an oxetanyl compound, a thietanyl compound, a (meth)acryloyl compound, a (meth)allyl compound, an allyl carbonate compound, an alkene compound, an alkyne compound, a bifunctional or higher active hydrogen compound, an acid anhydride, an alkoxysilane compound, and hydrolysates thereof. 
     In the present embodiment, it is preferable that the molded product be used as the optical material. Hereinafter, the polymerizable composition, which is used for preparing the optical material containing poly(thio)urethane or poly(thio)urethane urea as the resin, will be described. 
     The polymerizable composition according to the present embodiment includes (A) an isocyanate compound, and (B) at least one active hydrogen compound selected from the group consisting of a polythiol compound having two or more mercapto groups, a hydroxythiol compound having one or more mercapto groups and one or more hydroxyl groups, a polyol compound having two or more hydroxyl groups, and an amine compound. 
     (Isocyanate Compound (A)) 
     Examples of the isocyanate compound (A) include an aliphatic isocyanate compound, an alicyclic isocyanate compound, an aromatic isocyanate compound, a heterocyclic isocyanate compound, and an aromatic aliphatic isocyanate compound, and one or a combination of two or more thereof is used. These isocyanate compounds may include a dimer, a trimer, and a prepolymer. 
     Examples of the isocyanate compound include the compounds described as an example in International Publication No. WO2011/055540. 
     In the present embodiment, the isocyanate compound (A) preferably includes at least one selected from xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate, and more preferably includes at least one selected from xylylene diisocyanate, phenylene isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane. 
     (Active Hydrogen Compound (B)) 
     In the present embodiment, as the active hydrogen compound (B), at least one selected from the group consisting of a polythiol compound having two or more mercapto groups, a hydroxythiol compound having one or more mercapto groups and one or more hydroxyl groups, a polyol compound having two or more hydroxyl groups, and an amine compound can be used. Examples of the active hydride include the compounds described as an example in International Publication No. WO2016/125736. 
     From the viewpoint of the effects of the present invention, the active hydrogen compound (B) is preferably at least one selected from a polythiol compound having two or more mercapto groups and a hydroxythiol compound having one or more mercapto groups and one or more hydroxyl groups, and more preferably at least one selected from a polythiol compound having two or more mercapto groups. 
     The polythiol compound is preferably at least one selected from the group consisting of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), 2,5-bis(mercaptomethyl)-1,4-dithiane, bis(mercaptoethyl)sulfide, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithietane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 3-mercaptomethyl-1,5-dimercapto-2,4-dithiapentane, tris(mercaptomethylthio)methane, and ethylene glycol bis(3-mercaptopropionate), and more preferably at least one selected from the group consisting of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, and pentaerythritol tetrakis(3-mercaptopropionate). 
     In a case in which the second substrate  14  is the resin substrate, the resin substrate is preferably a thiourethane resin consisting of the following isocyanate compound and the following thiol compound, and the composition preferably contains the following isocyanate compound and the following thiol compound. 
     (Isocyanate Compound) 
     At least one selected from xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate. 
     (Thiol Compound) 
     At least one selected from the group consisting of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, and pentaerythritol tetrakis(3-mercaptopropionate). 
     In the present embodiment, a molar ratio of an active hydrogen group in the active hydrogen compound (B) to an isocyanato group in the isocyanate compound (A) is within a range of 0.8 to 1.2, preferably within a range of 0.85 to 1.15, and more preferably within a range of 0.9 to 1.1. Within the range described above, it is possible to obtain a resin suitably used as the optical material, particularly a plastic lens material for eyeglasses. 
     Examples of an optional additive include a specific wavelength absorbing agent, an adhesion improving agent, a polymerization catalyst, an internal mold release agent, an ultraviolet absorbing agent, and the like. In the present embodiment, in a case of obtaining polyurethane and polythiourethane, the polymerization catalyst may or may not be used. 
     Examples of the internal mold release agent include acidic phosphoric acid ester. Examples of the acidic phosphoric acid ester include phosphoric acid monoester and phosphoric acid diester, which can be used alone or in combination of two or more thereof. 
     Examples of the ultraviolet absorbing agent include a benzophenone-based ultraviolet absorbing agent, a triazine-based ultraviolet absorbing agent, a benzotriazole-based ultraviolet absorbing agent, and the like, and preferably a benzotriazole-based ultraviolet absorbing agent such as 2-(2H-benzotriazole-2-yl)-4-tert-octylphenol or 2-(5-chloro-2H-benzotriazole-2-yl)-4-methyl-6-tert-butylphenol. These ultraviolet absorbing agents can be used alone or in combination of two or more thereof. 
     It is possible to obtain the polymerizable composition by mixing the components described above by a predetermined method. 
     It is possible to obtain the molded product by filling the gap  20  with the polymerizable composition and then polymerizing the composition. Examples of a polymerization method include a known method in the related art, and a condition thereof is not particularly limited. 
     Since a condition differs depending on a type and a usage amount of components, a type and a usage amount of a catalyst, a shape of the mold, and the like, the polymerization condition is not limited, but the polymerization is carried out, approximately, for 1 to 50 hours at a temperature of −50 to 150° C. 
     In a case in which both the first substrate  12  and the second substrate  14  are molds, the molded product can be separated from the first substrate  12  and the second substrate  14  to obtain a thin film for lamination. In a case in which the second substrate  14  is the resin substrate, the molded product can be separated from the first substrate  12  and obtained as a laminated body of the layer, which is made of the molded product, and the resin substrate. 
     Note that as described above, by adhering the polarizing film to the front surface of the surface  14   a  in advance, it is possible to obtain the polarizing lens in which the layer made of the molded product, the polarizing film, and the resin substrate are laminated in this order. Since the molded product has a thick portion cured in the space  22  at the peripheral portion thereof, the thick portion can be scraped off as appropriate depending on the application, and in a case of the laminated body with the resin substrate, the thick portion can be scraped off as appropriate together with the resin substrate. 
     [Laminated Lens] 
     In the injection molding method according to the present embodiment, in a case in which the second substrate  14  constituting the mold is the resin substrate, a laminated lens  30  shown in  FIG. 7  is prepared. The laminated lens  30  includes a first resin layer  32  having an objective surface  32   a  and a second resin layer  36  (second substrate  14  made of the resin substrate). 
     The first resin layer  32  is provided with a protrusion portion  34  at a peripheral portion thereof, and the protrusion portion  34  is integrated to be embedded in the second resin layer  36 . A thickness of the protrusion portion  34  on a periphery of the first resin layer  32  is thicker than a thickness of the first resin layer  32  on a portion surrounded by the protrusion portion  34 . 
     The laminated lens  30  according to the present embodiment can be used as the laminated lens by performing polishing at a dotted line portion shown in  FIG. 7 . Further, it is possible to polish a facing surface  36   a  of the second resin layer  36 . 
     Although the embodiment of the present invention has been described above, the embodiment is an example of the present invention, and it is possible to adopt various configurations other than the above as long as the effects of the present invention are not impaired. 
     In  FIG. 7 , the example has been described in which the first resin layer  32  and the second resin layer  36  are curved. However, it is possible to adopt various shapes for the molded product depending on the application, and for example, both the first resin layer  32  and the second resin layer  36  may also be a substantially circular flat plate. 
     In  FIG. 7 , the example has been described in which the protrusion portion  34  is provided over the entire circumference of the periphery of the first resin layer  32 . However the protrusion portion  34  may be provided over a substantially half of the circumference of the periphery of the first resin layer  32 , and may be provided over any position selected from a substantially half of the circumference (½) to less than the entire circumference. 
     EXAMPLES 
     Hereinafter, the present invention will be described in more detail by Examples, but the present invention is not limited thereto. 
     [Casting Property] 
     The time required for casting the polymerizable composition for the optical material into the gap of the injection molding apparatus was evaluated based on the following criteria. 
     A: Casting into the gap was within 1 minute. 
     B: Casting into the gap exceeded 1 minute. 
     C: The air bubbles in the gap generated during casting did not escape, and thus casting into the gap was abandoned. 
     [Appearance (Presence or Absence of Air Bubbles)] 
     The air bubbles in the lens were evaluated based on the following criteria. 
     A: The air bubbles were not observed in the lens. 
     B: The air bubbles were observed at an edge portion of the lens. 
     C: The air bubbles were observed in the entire lens. 
     Example 1 
     (Preparation of Lens for Mold (Second Substrate  14 ) and Injection Molding Apparatus  10 ) 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent, and 0.00005 parts by weight of Plast Blue 8514 manufactured by ARIMOTO CHEMICAL CO., LTD. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A casting mold was prepared in which a front glass mold (R of the concave surface facing a back glass mold was 215.80 mm) and the back glass mold (R of the convex surface facing the front glass mold was 75.53 mm) were fixed by the tape to face each other. The preparation solution was cast into the gap between the molds (separation distance of a center portion was 1.2 mm), and a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold to obtain a lens having a diameter of 81 mm. The lens was processed to a diameter of 75 mm, and, out of an edge thickness of 11 mm, 7 mm in the thickness direction from the convex surface (surface  14   a ) and 2 mm of the thickness in the diameter direction from the edge portion (peripheral end portion) were scraped off to prepare the second substrate (resin substrate)  14  having a notch  24  over the entire circumference. 
     The glass mold having the concave surface (surface  12   a ) of which R was 215.80 mm was used as the first substrate  12 , and the end portion of the first substrate  12  and the end portion of the second substrate  14  were wound and fixed by the tape (fixing member  16 ) such that the concave surface (surface  12   a ) of the first substrate  12  and the convex surface (surface  14   a ) of the second substrate  14  face each other to prepare the injection molding apparatus  10  including the gap  20 . The separation distance of the center portion of the gap  20  was 0.5 mm. In the injection molding apparatus  10 , the space  22  is formed over the entire periphery of the gap  20 , which is surrounded by the tape (fixing member  16 ), the concave surface (surface  12   a ) of the first substrate  12 , and the notch  24 . An opening (injection portion  18 ) connecting with the space  22  was formed in the fixing member  16 . 
     (Preparation of Laminated Lens) A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A viscosity of the preparation solution measured at 20° C. with a B-type viscometer was 35 mPa·s. The preparation solution was injected at an injection rate of 30 ml/min by an injection tool including a pipette tip through the opening (injection portion  18 ) positioned at the upper end of the injection molding apparatus  10  obtained as described above. As a result of observation, as shown in  FIG. 2 , it was observed that the preparation solution was mainly moved downward in the space  22  and the gap  20  was filled with the preparation solution from the lower portion of the space  22 . After casting, a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold (first substrate  12 ) to obtain the laminated lens in which the resin layer was laminated on the resin substrate (second substrate  14 ). Further, the obtained lens was annealed at 120° C. for 2 hours. 
     The results of evaluation are shown in Table-1. 
     Example 2 
     (Preparation of Lens for Mold (Second Substrate  14 ) and Injection Molding Apparatus  10 ) 
     1.5 parts by weight of Tinuvin PS manufactured by BASF as the ultraviolet absorbing agent and 90.9 parts by weight of bis(2,3-epithiopropyl)disulfide were stirred and mixed at 30° C. to obtain a homogeneous solution. 9.1 parts by weight of a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 0.09 parts by weight of N,N-dicyclohexylmethylamine, and 0.02 parts by weight of N,N-dimethylcyclohexylamine were added in the homogeneous solution, and stirred and mixed at 20° C. to obtain a liquid mixture. The liquid mixture was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A casting mold was prepared in which a front glass mold (R of the concave surface facing a back glass mold was 215.80 mm) and the back glass mold (R of the convex surface facing the front glass mold was 75.53 mm) were fixed by the tape to face each other. The preparation solution was cast into the gap between the molds (separation distance of a center portion was 1.2 mm), and a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold to obtain a lens having a diameter of 81 mm. The lens was processed to a diameter of 75 mm, and, out of an edge thickness of 11 mm, 7 mm in the thickness direction from the convex surface (surface  14   a ) and 2 mm of the thickness in the diameter direction from the edge portion (peripheral end portion) were scraped off to prepare the second substrate (resin substrate)  14 , which is shown in  FIG. 1 , having a notch  24  over the entire circumference. 
     The glass mold having the concave surface (surface  12   a ) of which R was 215.80 mm was used as the first substrate  12 , and the end portion of the first substrate  12  and the end portion of the second substrate  14  were wound and fixed by the tape (fixing member  16 ) such that the concave surface (surface  12   a ) of the first substrate  12  and the convex surface (surface  14   a ) of the second substrate  14  face each other to prepare the injection molding apparatus  10  including the gap  20 , which is shown in  FIG. 1 . The separation distance of the center portion of the gap  20  was 0.5 mm. In the injection molding apparatus  10 , the space  22  was formed over the entire periphery of the gap  20 , which was surrounded by the tape (fixing member  16 ), the concave surface (surface  12   a ) of the first substrate  12 , and the notch  24 . The opening (injection portion  18 ) connecting with the space  22  was formed in the fixing member  16 . 
     (Preparation of Laminated Lens) 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin chloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A viscosity of the preparation solution measured at 20° C. with a B-type viscometer was 46 mPa·s. The preparation solution was injected at an injection rate of 25 ml/min by an injection tool including a pipette tip through the opening (injection portion  18 ) positioned at the upper end of the injection molding apparatus  10  obtained as described above. As a result of observation, as shown in  FIG. 2 , it was observed that the preparation solution was mainly moved downward in the space  22  and the gap  20  was filled with the preparation solution from the lower portion of the space  22 . After casting, a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold (first substrate  12 ) to obtain the laminated lens in which the resin layer was laminated on the resin substrate (second substrate  14 ). Further, the obtained lens was annealed at 120° C. for 2 hours. 
     The results of evaluation are shown in Table-1. 
     Comparative Example 1 
     (Preparation of Lens for Mold (Second Substrate  104 ) and Injection Molding Apparatus  100 ) 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent, and 0.00005 parts by weight of Plast Blue 8514 manufactured by ARIMOTO CHEMICAL CO., LTD. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A casting mold was prepared in which a front glass mold (R of the concave surface facing a back glass mold was 215.80 mm) and the back glass mold (R of the convex surface facing the front glass mold was 75.53 mm) were fixed by the tape to face each other. The preparation solution was cast into the gap between the molds (separation distance of a center portion was 1.2 mm), and a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold to obtain a lens having a diameter of 81 mm. The lens was processed to a diameter of 75 mm to prepare a second substrate (resin substrate)  104  shown in  FIG. 8 . 
     The glass mold having the concave surface (surface  102   a ) of which R was 215.80 mm was used as a first substrate  102 , and the end portion of the first substrate  102  and the end portion of the second substrate  104  were wound and fixed by the tape (fixing member  106 ) such that the concave surface (surface  102   a ) of the first substrate  102  and the convex surface (surface  104   a ) of the second substrate  104  face each other to prepare an injection molding apparatus  100  including a gap  110 , which is shown in  FIG. 8 . The separation distance of the center portion of the gap  110  was 0.5 mm. The opening (injection portion  108 ) connecting with the gap  110  was formed in the fixing member  106 . 
     (Preparation of Laminated Lens) 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A viscosity of the preparation solution measured at 20° C. with a B-type viscometer was 35 mPa·s. The preparation solution was injected at an injection rate of 3 ml/min by an injection tool including a pipette tip through the opening (injection portion  108 ) positioned at the upper end of the injection molding apparatus  100  obtained as described above. As a result of observation, it was observed that the preparation solution traveled through the concave surface (surface  102   a ) of the first substrate  102  and the convex surface (surface  104   a ) of the second substrate  104 , and the gap  110  was filled from the injection portion  108  from the lower portion while air was released from the injection portion  108 . After casting, a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold (first substrate  102 ) to obtain the laminated lens in which the resin layer was laminated on the resin substrate (second substrate  104 ). Further, the obtained lens was annealed at 120° C. for 2 hours. 
     The results of evaluation are shown in Table-1. 
     Comparative Example 2 
     (Preparation of Lens for Mold (Second Substrate  104 ) and Injection Molding Apparatus  100 ) 
     1.5 parts by weight of Tinuvin PS manufactured by BASF as the ultraviolet absorbing agent and 90.9 parts by weight of bis(2,3-epithiopropyl)disulfide were stirred and mixed at 30° C. to obtain a homogeneous solution. 9.1 parts by weight of a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 0.09 parts by weight of N,N-dicyclohexylmethylamine, and 0.02 parts by weight of N,N-dimethylcyclohexylamine were added in the homogeneous solution, and stirred and mixed at 20° C. to obtain a liquid mixture. The liquid mixture was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A casting mold was prepared in which a front glass mold (R of the concave surface facing a back glass mold was 215.80 mm) and the back glass mold (R of the convex surface facing the front glass mold was 75.53 mm) were fixed by the tape to face each other. The preparation solution was cast into the gap between the molds (separation distance of a center portion was 1.2 mm), and a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold to obtain a lens having a diameter of 81 mm. The lens was processed to a diameter of 75 mm to prepare the second substrate (resin substrate)  104  shown in  FIG. 6 . 
     The glass mold having the concave surface (surface  102   a ) of which R was 215.80 mm was used as the first substrate  102 , and the end portion of the first substrate  102  and the end portion of the second substrate  104  were wound and fixed by the tape (fixing member  106 ) such that the concave surface (surface  102   a ) of the first substrate  102  and the convex surface (surface  104   a ) of the second substrate  104  face each other to prepare the injection molding apparatus  100  including the gap  110 , which is shown in  FIG. 6 . The separation distance of the center portion of the gap  110  was 0.5 mm. The opening (injection portion  108 ) connecting with the gap  110  was formed in the fixing member  106 . 
     (Preparation of Laminated Lens) 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and 1.5 parts by weight of Viosob 583 manufactured by BASF as the ultraviolet absorbing agent. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter to obtain the preparation solution. A viscosity of the preparation solution measured at 20° C. with a B-type viscometer was 46 mPa·s. The preparation solution was injected at an injection rate of 2 ml/min by an injection tool including a pipette tip through the opening (injection portion  108 ) positioned at the upper end of the injection molding apparatus  100  obtained as described above. As a result of observation, it was observed that the preparation solution traveled through the concave surface (surface  102   a ) of the first substrate  102  and the convex surface (surface  104   a ) of the second substrate  104 , and the gap  110  was filled from the injection portion  108  from the lower portion while air was released from the injection portion  108 . After casting, a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the glass mold (first substrate  102 ) to obtain the laminated lens in which the resin layer was laminated on the resin substrate (second substrate  104 ). Further, the obtained lens was annealed at 120° C. for 2 hours. 
     The results of evaluation are shown in Table-1. 
     Comparative Example 3 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent, and 0.00005 parts by weight of Plast Blue 8514 manufactured by ARIMOTO CHEMICAL CO., LTD. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The preparation solution was obtained after the polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter. A viscosity of the preparation solution measured at 20° C. with a B-type viscometer was 36 mPa·s. The preparation solution was injected into the injection molding apparatus  100  (4C plano mold in which the center thickness of the gap  110  was set to 0.5 mm), which is shown in  FIG. 6 , using the glass mold as the first substrate  102  and the glass mold as the second substrate  104  at an injection rate of 2 ml/min by an injection tool including a pipette tip through the opening (injection portion  108 ) positioned at the upper end. After casting, a temperature was raised from 25° C. to 120° C. for 16 hours. The preparation solution was cooled to room temperature and removed from the first substrate  102  and the second substrate  104  to obtain a lens having a diameter of 81 mm. Further, the obtained lens was annealed at 120° C. for 2 hours. 
     The results of evaluation are shown in Table-1. 
     Comparative Example 4 
     A mixed solution was prepared by charging 0.035 parts by weight of dibutyltin dichloride, 0.1 parts by weight of Zelec UN manufactured by Stepan Company, 50.6 parts by weight of a mixture of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 1.5 parts by weight of Viosob 583 manufactured by BASF as an ultraviolet absorbing agent, and 0.00005 parts by weight of Plast Blue 8514 manufactured by ARIMOTO CHEMICAL CO., LTD. The mixed solution was stirred at 25° C. for 1 hour to be completely dissolved. Thereafter, 25.5 parts by weight of the thiol composition containing 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 23.9 parts by weight of the thiol composition containing pentaerythritol tetrakis(3-mercaptopropionate) were charged in this preparation solution, and were stirred at 25° C. for 30 minutes to obtain a homogeneous solution (polymerizable composition for the optical material). The preparation solution was obtained after the polymerizable composition for the optical material was defoamed at 600 Pa for 1 hour and filtered through a 1 μm PTFE filter. A viscosity of the preparation solution measured at 20° C. with a B-type viscometer was 36 mPa·s. An attempt was made to inject the preparation solution into the injection molding apparatus  100  (4C plano mold in which the center thickness of the gap  110  was set to 0.2 mm), which is shown in  FIG. 6 , using the glass mold as the first substrate  102  and the glass mold as the second substrate  104  by an injection tool including a pipette tip through the opening (injection portion  108 ) positioned at the upper end, but it was difficult to inject the preparation solution due to the intrusion of air, and casting was abandoned. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Example 
                   
                 Comparative Example 
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 1 
                 2 
                 1 
                 2 
                 3 
                 4 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Casting property 
                 A 
                 A 
                 B 
                 B 
                 B 
                 C 
               
               
                 Appearance 
                 A 
                 A 
                 C 
                 C 
                 C 
                 — 
               
               
                 (presence or 
               
               
                 absence of 
               
               
                 air bubbles) 
               
               
                   
               
            
           
         
       
     
     As shown in Table-1, the injection molding apparatuses of Examples 1 and 2 had excellent casting property, and it was possible to homogeneously fill a narrow gap formed between the two substrates even with the composition having a high viscosity. Further, in the lenses obtained by the injection molding apparatuses of Examples 1 and 2, the mixing of air bubbles and the like were suppressed. As described above, it has been clarified that by using the injection molding apparatuses of Examples 1 and 2, the lens having an excellent appearance can be produced with a good yield. 
     This application claims priority based on Japanese Patent Application No. 2019-092682 filed on May 16, 2019, the entire disclosure of which is incorporated herein by reference. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10 ,  100 : injection molding apparatus 
               12 ,  102 : first substrate 
               12   a ,  102   a : surface (curved surface) 
               14 ,  15 ,  104 : second substrate 
               14   a ,  15   a ,  15   b ,  104   a : surface (curved surface) 
               16 ,  106 : fixing member 
               18 ,  108 : injection portion 
               20 ,  110 : gap 
               22 ,  23 : space 
               24 : notch 
               30 : laminated lens 
               32 : first resin layer 
               32   a : front surface 
               34 : protrusion portion 
               36 : second resin layer 
               36   a : front surface 
             i: width of space  22  in thickness direction 
             ii: width of space  22  in diameter direction 
             iii: diameter of second substrate  36   
             a, b: radius of curvature 
             c, d: width of second substrate in thickness direction