JP2005103915A - Method for producing plastic lens for glasses and plastic leans for glasses - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a plastic lens for glasses with striae and bubbles reduced. <P>SOLUTION: When a plastic lens raw material is injected into a molding space and polymerized/molded by using a plastic lens molding mold 1 having an upper mold 2 for molding the concave surface of the lens, a lower mold 3, and a side member 5, when an angle which meets the relationship of sinθ=d/(2R) is θ° (wherein d is the diameter of the upper mold; and R is a radius of curvature when the molding surface of the upper mold is made to approximate a spherical surface), the mold 1 is slanted by an angle which is at least θ° and smaller than θ°+15° to a horizontal surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a plastic lens for spectacles and a plastic lens for spectacles manufactured by the manufacturing method.

  A casting polymerization mold (mold), which is a mold used for molding plastic lenses for spectacles, has two glass molds facing each other on the convex side and concave side of the lens, and a soft resin gasket or adhesive tape around it. What is sealed with is generally used. As a holding method at the time of polymerization, after injecting a plastic lens material into a casting polymerization mold comprising a mold and a gasket into a mold comprising two molds and a gasket, the convex side of the casting polymerization mold is placed on the upper side. Alternatively, a method is known in which polymerization is performed while holding the lower side.

As an example, for example, a plastic lens raw material is injected into a casting polymerization mold consisting of a mold and a gasket into a mold consisting of two molds and a gasket, and then the mold is placed at 45 ° to the horizontal plane. A manufacturing method of a lens that performs polymerization while fixing at an angle in a range of ˜135 ° is known (see Patent Document 1). Also, for example, after injecting a plastic lens material into a lens mold for molding a semi-finished lens, the convex side of the lens mold is fixed upward and fixed at an angle of 0 ° to less than 45 ° with respect to a horizontal plane. A manufacturing method of a lens that performs polymerization is known (see Patent Document 2).
JP-A-9-193256 Japanese Patent Laid-Open No. 2003-145555

  By the way, according to Patent Document 2, the method described in Patent Document 1 is considered to have a problem that striae easily occur, and the method of Patent Document 2 is the paragraph number [ [0005] As described in [0005], there is a problem that dust and bubbles are difficult to move to the periphery. Furthermore, since eyeglass lenses have many refractive powers, there are many types of molds. It was not uncommon to decide how to place these molds through thought and error. The present invention has been made to solve such problems, and its purpose is to produce a spectacle lens with few striae, dust and bubbles at the center of the lens, and many types. It is to provide a method for determining an optimum holding method for each of the molds.

As a means for solving the above-mentioned problem, the first means is:
An upper mold for molding the convex surface of the lens, a lower mold for molding the concave surface of the lens by arranging the molding surface of the upper mold so as to face the molding surface, and the upper mold and A method of manufacturing a plastic lens for spectacles, which uses a plastic lens mold having a side surface member that covers a side surface portion of a molding space formed by a lower mold, and injects a plastic lens material into the molding space to mold the lens. ,
In the molding, when the angle at which the relationship of sin θ = d / (2R) is established is θ °, the angle of the molding die with respect to the horizontal plane is not less than θ ° and less than θ ° + 15 °. It is a manufacturing method of the plastic lens for spectacles characterized by tilting only.
Here, d is the diameter of the upper mold, and R is the radius of curvature when the molding surface of the upper mold is approximated to a spherical surface.
The second means is
The plastic lens raw material is a material for polymerizing in the molding space, and is a method for producing a plastic lens for spectacles according to a first means.
The third means is
The plastic lens raw material is a material containing a mixture of a polyisocyanate compound and a polythiol compound, and is a method for producing a plastic lens for spectacles according to a second means.
The fourth means is
The plastic lens raw material is an epithio group-containing compound, which is a method for producing a plastic lens for spectacles according to a second means.
The fifth means is
A plastic lens for spectacles manufactured by the method for manufacturing a plastic lens for spectacles according to any one of the first to fourth means.

  In the molding, when the angle at which the relationship of sin θ = d / (2R) is established is θ, the molding die is at an angle of θ ° or more with respect to the horizontal plane and less than θ ° + 15 °. By tilting, dust and bubbles present at the center of the molded lens can be reduced regardless of the type of mold, and the occurrence of striae can be reduced. In this case, if the mold is at an angle θ ° or more and less than θ ° + 15 ° with respect to the horizontal plane, a certain effect can be obtained. The angle is preferably not less than θ ° and less than θ ° + 5 °. It is estimated that such an effect is obtained for the following reason. That is, having the above relationship means that the end surface of the upper mold is the highest in the height direction (Y-axis direction) with respect to the horizontal plane (X-axis direction) among the entire upper mold. Is to hold. If held in this way, regardless of the type of mold, dust and bubbles are easily detached from the center, and polymerization is also performed uniformly, reducing the occurrence of striae. It seems to be.

  In the case of an upper mold such as an aspherical design or a progressive design, the molding surface of the upper mold is an aspherical surface, so that there are a large number of curvature radii. Therefore, in the case of an aspherical surface, it approximates the spherical surface and uses the radius of curvature of the spherical surface. In the production of spectacle lenses, the mold diameter and curvature radius of the upper mold are diversified due to the high spherical power and astigmatic power, and the number of types of molds increases. According to the present invention, it is not necessary to determine how to place various types of molds by trial and error, and how to place the molds can be easily determined. The type of lens monomer used in the present invention is not particularly limited. Examples of the lens monomer preferably used include a mixture of a polyisocyanate compound that is a raw material of a polythiourethane resin and a polythiol compound, and an epithio group-containing compound.

〔Example〕
1 and 2 are explanatory views of a method for manufacturing a plastic lens for spectacles according to an embodiment of the present invention, and FIG. 3 is an explanatory view of the relationship between angles θ, d, and R. 1 is a cross-sectional view of the mold, and FIG. 2 is an external view of the mold. Hereinafter, a method for manufacturing a plastic lens for spectacles according to an embodiment of the present invention and a plastic lens for spectacles manufactured by the method will be described with reference to these drawings.

  1 and 2, a mold 1 for a plastic lens for spectacles includes an upper mold 2 for molding the convex surface of the lens, and a molding surface 2a of the upper mold 2 and its molding surface 3a are opposed to each other. The lower mold 3 is arranged to mold the concave surface of the lens, and the side mold 5 covers the side surface of the molding space 4 formed by the upper mold 2 and the lower mold 3. In this embodiment, glass molds were used as the upper mold 2 and the lower mold 3. Moreover, as the side member 5, an adhesive tape was used.

  When the plastic lens for spectacles is molded using the molding die 1, the plastic lens raw material 6 is injected and filled into the molding space 4, and the molding die 1 is inclined with respect to the horizontal plane 7 by an angle θ. In this state, polymerization is performed and molding is performed. Here, the angle θ ° formed by the mold 1 and the horizontal plane 7 is precisely the surface 8 (the surface indicated by the dotted line in FIG. 1) including a circle that partitions the outer shape of the molding surface 2 a of the upper mold 2. An angle formed by the horizontal plane 7. However, the surface 8 is substantially parallel to a surface 8a (a surface indicated by a one-dot chain line in FIG. 1) including a circle that partitions the outer shape of the back side of the lower mold 3. Therefore, in this embodiment, the angle formed by the surface 8a and the horizontal plane 7 is θ °.

Here, the angle θ ° is an angle at which a relationship of sin θ = d / (2R) is established. Here, d is the diameter of the upper mold, and R is the radius of curvature when the molding surface of the upper mold is approximated to a spherical surface. The above relational expression is obtained as follows. FIG. 3 is an explanatory diagram of a relational expression of sin θ = d / (2R). In FIG. 3, a straight line including a horizontal plane is defined as an X axis, and a straight line perpendicular to the horizontal plane is defined as a Y axis. Now, inclining the mold 1 so as to make an angle θ ° with respect to the horizontal plane 7 means that the surface 8 including the circle partitioning the outer shape of the molding surface 2a of the upper mold 2 in FIG. Same as tilting. Then, as is clear from FIG. 3, the following expression is established.
x ² + y ² = d ² (1)
x ² + (R−y) ² = R ² (2)
Organizing equation (2) above,
x ² + y ² = 2Ry (3)
It becomes.
From FIG.
sin θ = y / d (4)
It is. Substituting (1) and (3) by squaring (4),
(Sin θ) ² = (y / d) ² = y ² / (x ² + y ² ) = y ² / (2Ry)
= Y / (2R) = (d · sin θ) / (2R)
It becomes. Therefore, a relationship of sin θ = d / (2R) is obtained.

Table 1 listed below shows the θ when the diameter of the upper mold (mold diameter) d and the radius of curvature (upper mold radius of curvature) R when the molding surface of the upper mold is approximated to a spherical surface are variously changed. The values are calculated and tabulated. In Table 1, the values of θ + 5 and θ + 15 are also listed.

Next, using the mold 1 described above, the plastic lens raw material 6 is injected into the molding space 4 of the mold 1 in a state where the mold 1 is tilted at a predetermined angle with respect to the horizontal plane to cause a polymerization reaction. A molded example will be described.
(Example 1, Comparative Example 1)
First, as plastic lens raw material 6, m-xylylene diisocyanate 45 parts by weight, pentaerythritol tetrakismercaptoacetate 25 parts by weight, dimercaptomethyldithiane 30 parts by weight, dimethyltin dichloride (catalyst) 0.5 part by weight, 2- (2 ' -Hydroxy 5'-octylphenyl) benzotriazole 0.10 parts by weight and butoxyethyl acid phosphate 0.10 parts by weight, a mold diameter (d), an upper mold radius of curvature (R), a tilt angle of the mold 1 Example 1 and Comparative Example 1 are examples where polymerization and molding are performed with some changes. The polymerization / molding was performed by sequentially heating from 20 ° C. to 120 ° C. over 24 hours in a hot air circulating furnace while maintaining the mold 1 at a predetermined tilt angle. The plastic lens obtained by the molding was examined with the naked eye for the presence or absence of striae and striae. The results are shown in Table 2. In Table 2, 200 pieces were molded in each case. The distance between the centers of the molding surfaces 2a and 3a was all 8 mm.

  In Table 2, the mold diameter (d) and the upper mold radius of curvature (R) are the same in Example 1 and Comparative Example 1, but the tilt angle of the mold 1 is different between the two. That is, in the example, the tilt angle is set to an angle that is greater than or equal to θ ° and less than θ ° + 15 °, whereas in the comparative example, the tilt angle is set to a range that is out of the angle range. As is apparent from Table 2, if the angle is not less than θ ° and less than θ ° + 5 °, the mold diameter (d) and the upper mold radius of curvature (R) given as examples will be・ No striae was observed. When approaching θ ° + 15 °, striae defects were slightly observed, but are within the practical range. On the other hand, as shown in the comparative example, it can be seen that when the angle is less than θ ° or is greater than θ ° + 15 °, both the defect and striae increase rapidly.

(Example 2, comparative example 2)
As plastic lens raw material 6, bis (β-epithiopropyl) sulfide 70.0 parts by weight, bis (mercaptomethyl) -1,4-dithian 6.88 parts by weight, bis (mercaptomethyl) bicycloheptane 4.10 parts by weight, tetrabutylphosphonium bromide 0.05 Molded in the same manner as in Example 1 above, except that a material mixed with parts by weight, 0.01 parts by weight of tetra-n-butyl-1,3-diacetoxy distanoxane, and 50 ppm of butoxyethyl acid phosphate was used. These are listed in Table 3 as Example 2 and Comparative Example 2.

  As is clear from Table 3, in the case of Example 2 and Comparative Example 2, as in the case of Example 1 and Comparative Example 1 described above, the inclination angle of the mold 1 is not less than θ °, and θ ° + 5 °. If the angle is less than 1, no millet or striae was observed in all cases of the mold diameter (d) and the upper mold radius of curvature (R) given as examples. When approaching θ ° + 15 °, striae defects were slightly observed, but are within the practical range. On the other hand, as shown in the comparative example, it can be seen that when the angle is less than θ ° or is greater than θ ° + 15 °, both the defect and striae increase rapidly.

  In the above-described embodiment, an example in which an adhesive tape is used as the side member 5 of the mold 1 has been described. That is, the example which formed the molding space 4 with the adhesive tape, and fixed the upper mold 2 and the lower mold 3 simultaneously was given. However, a gasket or the like may be used as the side member. FIG. 4 is a cross-sectional view showing another example of a plastic lens mold for glasses. In FIG. 4, a plastic mold 10 for an eyeglass plastic lens is arranged such that an upper mold 20 for molding the convex surface of the lens, and a molding surface 20a of the upper mold 20 and its molding surface 30a face each other. A lower mold 30 that molds the concave surface of the lens, and a side member 50 that covers the side surface of the molding space 40 formed by the upper mold 20 and the lower mold 30. In this embodiment, as the side member 50, a gasket member provided with a lens housing fixing portion capable of fitting and fixing the upper mold 20 and the lower mold 30 is used. According to this, the upper mold 20 and the lower mold 30 can be firmly fixed with an accurate positional relationship.

  The present invention can be used for molding a plastic lens for spectacles.

It is explanatory drawing of the manufacturing method of the plastic lens for spectacles concerning the Example of this invention. It is explanatory drawing of the manufacturing method of the plastic lens for spectacles concerning the Example of this invention. It is explanatory drawing of the relationship of angle (theta), d, and R. FIG. It is sectional drawing which shows the other example of the plastic lens shaping die for spectacles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 Plastic lens mold 2 for glasses 2,20 Upper mold 2a, 20a Molding surface 3,30 Lower mold 3a, 30a Molding surface 4,40 Molding space 5,50 Side member 6,60 Plastic raw material 7 horizontal plane

Claims (5)

An upper mold for molding the convex surface of the lens, a lower mold for molding the concave surface of the lens by arranging the molding surface of the upper mold so as to face the molding surface, and the upper mold and A method of manufacturing a plastic lens for spectacles, which uses a plastic lens mold having a side surface member that covers a side surface portion of a molding space formed by a lower mold, and injects a plastic lens material into the molding space to mold the lens. ,
In the molding, when the angle at which the relationship of sin θ = d / (2R) is established is θ °, the angle of the molding die with respect to the horizontal plane is not less than θ ° and less than θ ° + 15 °. A method of manufacturing a plastic lens for spectacles, characterized by tilting only.
Here, d is the diameter of the upper mold, and R is the radius of curvature when the molding surface of the upper mold is approximated to a spherical surface.   2. The method for manufacturing a plastic lens for spectacles according to claim 1, wherein the plastic lens raw material is a material that is polymerized in the molding space.   3. The method for producing a plastic lens for spectacles according to claim 2, wherein the plastic lens material is a material containing a mixture of a polyisocyanate compound and a polythiol compound.   The method for producing a plastic lens for spectacles according to claim 2, wherein the plastic lens raw material is an epithio group-containing compound.   A plastic lens for spectacles produced by the method for producing a plastic lens for spectacles according to claim 1.

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