JP2014202904A - Optical element and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element and a manufacturing method of the optical element that are excellent in adhesion between a lens base material and a functional film and have occurrence of warpage suppressed.SOLUTION: The optical element comprises: a lens base material; an adhesion layer that is placed on the lens base material; and a functional film that is placed on the adhesion layer. The adhesion layer includes ester-based polyurethane, and an elongation of the adhesion layer is 1050 to 1400%, and a Young's modulus of the adhesion layer is 400 N/mmor less.

Description

  The present invention relates to an optical element and a method for manufacturing the same.

In order to impart functions such as scratch resistance to an optical substrate (particularly, a plastic lens), it is a common practice to further form a functional layer on the surface of the optical substrate. At that time, an adhesive layer (primer layer) is used in order to ensure adhesion between the optical substrate and the functional layer.
For example, in patent document 1, the primer composition for optical articles containing the urethane resin which has frame | skeleton derived from a polycarbonate is disclosed. More specifically, in the Example column of Patent Document 1, Superflex 460 or the like is used as the urethane resin.

International Publication No. 2012/036084

On the other hand, in recent years, optical elements represented by spectacle lenses and the like have been required to further improve optical characteristics.
The present inventors have found that when the primer composition described in Patent Document 1 is used as an adhesive layer between a lens substrate and a functional film, warpage occurs in the obtained optical element. When such a warp occurs, the incident angle changes depending on the position where light enters, and predetermined optical characteristics cannot be obtained.
Further, in recent years, there has been a demand for further improvement in the adhesion between the lens substrate and the functional film. However, when the primer composition described in Patent Document 1 is used, the adhesion is not always required. The required level was not reached, and further improvements were necessary.

  In view of the above circumstances, an object of the present invention is to provide an optical element that is excellent in adhesion between a lens substrate and a functional film and in which the occurrence of warpage is suppressed, and a method for manufacturing the same.

As a result of intensive studies on the problems of the prior art, the present inventors have found that the above-described problems can be solved by using an adhesive layer containing ester polyurethane and exhibiting a predetermined elongation and Young's modulus.
That is, it has been found that the above object can be achieved by the following configuration.

(1) An optical element comprising a lens substrate, an adhesive layer disposed on the lens substrate, and a functional film disposed on the adhesive layer,
The adhesive layer contains an ester polyurethane,
The elongation of the adhesive layer is 1050 to 1400%,
An optical element in which the Young's modulus of the adhesive layer is 400 N / mm ² or less.
(2) The optical element according to (1), wherein the polyester urethane contains an aromatic group.
(3) The optical element according to (1) or (2), wherein the adhesive layer is formed from a composition containing an ester polyurethane latex.
(4) The method for manufacturing an optical element according to (3),
A coating film forming step of coating the composition on the surface of the lens substrate to form a coating film,
A laminating step of bonding a functional film on the coating film;
The manufacturing method of an optical element provided with the heating process which heat-processes after a lamination process.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in the adhesiveness of a lens base material and a functional film, the optical element with which generation | occurrence | production of curvature was suppressed, and its manufacturing method can be provided.

It is sectional drawing which shows one embodiment of the optical element of this invention.

Below, the suitable aspect of the optical element of this invention and its manufacturing method is demonstrated.
One of the features of the optical element of the present invention is that an adhesive layer containing ester polyurethane and having a predetermined elongation and Young's modulus is used. The detailed reason why the desired effect can be obtained by using this adhesive layer is unknown, but the Young's modulus of the adhesive layer is low and the elongation is sufficiently high, so that the warp of the optical element can be alleviated. it can.

FIG. 1 is a cross-sectional view of an embodiment of the optical element of the present invention.
The optical element 10 shown in the figure has a laminated structure in which a lens substrate 12, an adhesive layer 14, and a functional film 16 are laminated in this order. In FIG. 1, the adhesive layer 14 and the functional film 16 are laminated only on one main surface 12 a (first surface) of the lens base material 12. The adhesive layer 14 and the functional film 16 may be laminated on both surfaces of the two main surfaces (the first surface 12a and the second surface 12b).
Below, each element (the lens base material 12, the contact bonding layer 14, and the functional film 16) which comprises the optical element 10 is each explained in full detail.

(Lens base material)
The lens substrate 12 has a first surface 12a and a second surface 12b, and is a substrate that supports the adhesive layer 14 and the functional film 16 on the surface.
The type of the lens base material 12 is not particularly limited, and a normal lens base material such as plastic or inorganic glass can be used. Among them, a plastic lens base material is preferable because it is easy to handle. A lens substrate is more preferable.
The material of the plastic lens base material is not particularly limited. For example, acrylic resin, thiourethane resin, methacrylic resin, allyl resin, episulfide resin, polycarbonate resin, polyurethane resin, polyester resin, polystyrene resin , Episulfide resin, polyethersulfone resin, poly-4-methylpentene-1 resin, diethylene glycol bisallyl carbonate resin (CR-39), polyvinyl chloride resin, halogen-containing copolymer, or sulfur-containing copolymer. .
The lens substrate 12 includes lens processing such as a finished product (glass lens) having a desired optical surface on both surfaces, a semi-finished product (semi-finish lens) having a convex surface finished in a desired shape, and grinding and polishing. Lens blanks that have not been applied may be used.

The thickness of the lens substrate 12 is not particularly limited, and is often about 1 to 30 mm from the viewpoint of handleability.
Moreover, the lens base material 12 may not be transparent as long as it has translucency, and may be colored.
Furthermore, in FIG. 1, the surface shape of the lens substrate 12 is a convex surface and a concave surface, but the surface shape is not limited and is selected from any shape such as a flat surface, a convex surface, or a concave surface.

(Adhesive layer)
The adhesive layer 14 is a layer for ensuring the adhesion between the lens substrate 12 and the functional film 14.
The adhesive layer 14 includes ester polyurethane. The ester polyurethane is a polyurethane containing an ester bond, and is a polymer obtained by copolymerizing a polyester polyol and a polyisocyanate, for example. The polyester polyol is obtained by reacting a polybasic carboxylic acid and a polyhydric alcohol.
In addition, it is preferable that the aromatic polyurethane is contained in ester polyurethane at the point which the effect of this invention is more excellent. The method for introducing an aromatic group into the ester polyurethane is not particularly limited, and examples thereof include a method of using an aromatic isocyanate and / or a polyvalent aromatic carboxylic acid when producing a polyester polyol.
The aromatic group only needs to be contained in the main chain or side chain of the ester-based polyurethane, and the main chain is preferable in that the effect of the present invention is more excellent. In the case where the main chain includes an aromatic group, for example, an arylene group (for example, a phenylene group) may be included.

  Examples of the polybasic carboxylic acid used in the production of the polyester polyol include aliphatic carboxylic acids and aromatic carboxylic acids. More specifically, for example, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid , Isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, or anhydride or ester formability of these dicarboxylic acids Derivatives and the like.

  It does not specifically limit as a polyhydric alcohol used at the time of manufacture of a polyester polyol, A conventionally well-known thing can be used. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol , Triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, triethylene glycol, polycaprolactone diol, dimer diol, bisphenol A , Glycols such as hydrogenated bisphenol A; ethylene glycol, diethylene glycol, triethylene glycol, Starting one or more compounds having two active hydrogen atoms such as pyrene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc. Examples of the agent include polyhydric alcohol components such as polyethers obtained by addition polymerization of one or more monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran and cyclohexylene by a conventional method. it can.

  The polyisocyanate used in the production of the ester polyurethane may be aromatic, alicyclic or aliphatic. Further, it may be a bifunctional isocyanate having two isocyanate groups in one molecule, or may be a trifunctional or higher polyisocyanate having three or more isocyanate groups in one molecule. Or you may use in combination of two or more.

  For example, as the bifunctional polyisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4 ′ -Diphenylmethane diate, 2,2'-diphenylmethane diisocyanate, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisonate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, etc. Aromatic ones, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, alicyclic ones such as methylcyclohexane diisocyanate, butane-1,4-diiso Aneto, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, there may be mentioned aliphatic, such as lysine isocyanate.

Trifunctional or higher polyisocyanates include 1-methylbenzole-2,4,6-triisocyanate, 1,3,5-trimethylbenzole-2,4,6-triisocyanate, biphenyl-2,4,4. '-Triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2', 5,5 'tetraisocyanate, Triphenylmethane-4,4 ′, 4 ″ -triisocyanate, polymeric MDI and the like can be mentioned. Other urethane prepolymers can also be used.
Moreover, polyisocyanate is not restricted to one type, Two or more types may be sufficient. For example, one type of aliphatic isocyanate and two types of aromatic isocyanate may be used in combination.

  The content of the ester polyurethane in the adhesive layer 14 is not particularly limited, but is preferably included as a main component. Here, the main component is intended to be 80% by mass or more with respect to the total mass of the adhesive layer 14. In addition, 90 mass% is more preferable with respect to the adhesive layer 14 total mass, and, as for the content of the ester-type polyurethane in the adhesive layer 14, the effect of this invention is more excellent, and 95 mass% is still more preferable. The upper limit is not particularly limited, but it is preferable that the adhesive layer 14 is substantially composed of an ester-based polyurethane, and more preferably 100% by mass. Here, “substantially” intends to be composed of an ester-based polyurethane except for inevitable impurities.

  The glass transition point (Tg) of the ester polyurethane is not particularly limited, but is preferably −10 ° C. or less, more preferably −20 ° C. or less in terms of better adhesiveness. The lower limit is not particularly limited, but is often -40 ° C or higher.

The elongation (%) of the adhesive layer 14 is 1050 to 1400%, and the occurrence of warpage of the optical element 10 is further suppressed, or the adhesion between the lens substrate 12 and the functional film 16 is more excellent. Therefore, 1200 to 1400% is preferable, and 1250 to 1350% is more preferable.
When the elongation is less than 1050% and more than 1400%, the warp of the optical element 10 is increased, or the adhesion between the lens substrate 12 and the functional film 16 is inferior.
The measuring method of the elongation of the adhesive layer 14 is performed according to JIS K 6251.

The Young's modulus (N / mm ² ) of the adhesive layer 14 is 400 N / mm ² or less, and the occurrence of warpage of the optical element 10 is further suppressed, or the adhesion between the lens substrate 12 and the functional film 16. Is more preferably 350 N / mm ² or less. When the Young's modulus exceeds 400 N / mm ² , the warp of the optical element 10 increases, or the adhesion between the lens substrate 12 and the functional film 16 is inferior.
The lower limit of Young's modulus is not particularly limited, but is often 0.1 N / mm ² or more.
The measuring method of the Young's modulus of the adhesive layer 14 is performed according to JIS K 6251.

  The thickness of the adhesive layer 14 is not particularly limited, but the film thickness after curing is preferably 3.8 μm or more, and more preferably 4.0 μm or more in terms of better adhesion between the lens substrate 12 and the functional film 16. .

The method for forming the adhesive layer 14 is not particularly limited, and a method of applying a composition containing the above ester polyurethane latex (hereinafter also referred to as ester polyurethane latex) onto the lens substrate 12 and then performing a curing treatment, A method of separately preparing a sheet-like adhesive layer 14 exhibiting the above-mentioned predetermined properties and bonding it onto the lens substrate 12 can be used.
In addition, the aspect using the composition containing ester polyurethane latex is explained in full detail in a back | latter stage.

(Functional film)
The functional film 16 is a film that is bonded onto the adhesive layer 14 described above.
The kind in particular of the functional film 16 is not restrict | limited, According to the function to give to the lens base material 12, an optimal film is suitably selected. For example, an impact-resistant film, a scratch-resistant film, a polarizing film, a light control film, an easily dyeable film, a specific wavelength cut film (ultraviolet ray / infrared ray) and the like can be mentioned.
The material of the functional film 16 is not particularly limited, but polymer materials such as polycarbonate, polyethylene terephthalate, polyamide, polyester, polyimide, polyurethane, olefin elastomer, triacetyl cellulose, cycloolefin polymer, poly (meth) acrylate, and polyvinyl alcohol are available. Can be mentioned. Of these, polyester is preferable.

As a preferred embodiment of the functional film 16, a functional film having an elongation of 200% or less is preferable. Especially, the elongation of the functional film 16 is more preferably 180% or less, and further preferably 140% or less. Although a minimum in particular is not restrict | limited, From the point of the characteristic of material, it is often 10% or more. If it is the said functional film, the adhesiveness of a lens base material and a functional film will be more excellent, or generation | occurrence | production of the curvature of an optical element will be suppressed more.
In addition, the measuring method of elongation is performed according to JIS K 6251.

  The thickness of the functional film 16 is not particularly limited, but considering the minimum thickness of the optical element 10, the thickness of the functional film 16 is preferably 0.2 mm or less, and more preferably 0.1 mm or less.

  The optical element 10 including the lens substrate 12, the adhesive layer 14, and the functional film 16 can be used for various applications. For example, a spectacle lens etc. are mentioned.

(Optical element manufacturing method)
The manufacturing method of the optical element described above is not particularly limited, and a known method can be adopted. Especially, the manufacturing method provided with the following processes is preferable at the point which is excellent in productivity and can manufacture a desired optical element efficiently.
(Coating film forming process) A process of applying a composition containing an ester polyurethane latex on the surface of a lens substrate to form a coating film (Lamination process) A process of bonding a functional film on the coating film (heating process) ) Step of performing heat treatment after laminating step Hereinafter, the procedure of the above step will be described in detail.

(Coating film formation process)
A coating-film formation process is a process of apply | coating the composition containing ester polyurethane latex on the surface of the lens base material mentioned above, and forming a coating film.
The definitions of the lens substrate and ester polyurethane used in this step are as described above.
The ester polyurethane latex may be a so-called self-emulsifying type or a forced emulsifying type using a surfactant or the like.
The solvent contained in the composition is usually water. An organic solvent may be included as long as the effects of the invention are not impaired.
The pH of the composition is not particularly limited, but 4 to 10 is preferable because it has little influence on the lens substrate and is excellent in handleability.

The average particle diameter of the ester polyurethane particles contained in the latex is not particularly limited, but is preferably about 0.01 to 0.50 μm. If it is in the said range, manufacture of a latex will become easier and the smoothness of an contact bonding layer will improve more.
In addition, as a measuring method of an average particle diameter, it can measure by the well-known light-scattering method (nanotrack particle size distribution measuring apparatus).
The content of the ester-based polyurethane particles in the latex is not particularly limited, but is preferably 20 to 60% by mass with respect to the total mass of the latex from the viewpoint of easy handling and easier adjustment of the film thickness.

  As the polyester-based polyurethane latex, a commercially available product can also be used. Specific examples include the “Superflex” series manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

A method for applying the composition onto the lens substrate is not particularly limited, and a known method (for example, a screen printing method, a dip coating method, a spray coating method, a spin coating method, an ink jet method, a pad printing, or the like) can be employed. .
The thickness in particular of the coating film formed on a lens base material is not restrict | limited, The thickness which becomes the thickness of the contact bonding layer mentioned above is selected suitably.
In this step, if necessary, the composition may be applied to the lens substrate and then dried to remove the solvent. By removing the remaining solvent, it is possible to suppress the generation of minute cracks and voids due to the vaporization and expansion of the solvent in the adhesive layer in the heating step described later.
A hot air dryer or the like can be used as a drying method, and the temperature may be a heat treatment at 40 ° C. to 80 ° C.

(Lamination process)
A lamination process is a process of bonding a functional film on the coating film formed at the said coating-film formation process.
The definition of the functional film used is as described above.
The method in particular of bonding a functional film on a coating film is not restrict | limited, A well-known method is employable. For example, the method of bonding a functional film on the said coating film and pressurizing under normal pressure is mentioned.

(Heating process)
A heating process is a process which heat-processes with respect to the laminated body provided with the lens base material obtained by the said lamination process, a coating film, and a functional film. By carrying out this step, the coating film is cured, and the adhesion between the lens substrate and the functional film is improved.
The conditions for the heat treatment are not particularly limited, and optimum conditions are appropriately selected according to the materials used. From the viewpoint of productivity, 0.5 to 100 to 140 ° C. (preferably 110 to 130 ° C.). It is preferable to heat for -4.0 hours (preferably 1.0-3.0 hours).

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

  In Examples and Comparative Examples to be described later, a polyester film having impact resistance (trade name: Lumirror (100-U48), elongation: 120 to 200%, manufactured by Toray Industries, Inc.) was used as the functional film.

<Example 1>
(1) Adhesive force evaluation After applying Daiichi Kogyo Seiyaku Superflex 740 as an ester polyurethane latex to a lens (our NL5AS) to form a coating film, the functional film is formed into a 15 × 50 mm strip. The adhesive was cured at 120 ° C. for 1 hour, and the adhesive strength when the film was pulled in the direction perpendicular to the lens was measured. The case where there was an adhesive strength of 0.9 kg or more as a criterion was judged as having sufficient adhesive strength. The results are shown in Table 1.
The adhesive layer had a thickness of 4.0 μm.
(2) Deformation Evaluation After applying First Industrial Pharmaceutical Superflex 740 as an ester polyurethane latex to the entire surface of a flat lens (φ65) to form a coating film, a functional film is pasted on the coating film. The adhesive was cured at 120 ° C. for 1 hour. The adhesive layer had a thickness of 4.0 μm.
Thereafter, heat treatment was further performed at 120 ° C. for 3 hours, and the amount of warpage of the obtained lens was measured. In addition, the case where the lens warped to the functional film side was set to +, and the case where the lens warped to the opposite side of the functional film was set to-. As a criterion for judgment, a lens having an amount of warpage within ± 0.5 mm was judged as an allowable range with little deformation of the lens. The results are shown in Table 1.
As a method for measuring the amount of warpage, a lens was placed on a flat surface plate, and the clearance between the surface plate and the lens was measured with a thickness gauge.

<Example 2, Comparative Examples 1-7>
As shown in Table 1 to be described later, a lens was prepared according to the same procedure as in Example 1 except that the type of ester polyurethane latex was changed, and the above (1) adhesive strength evaluation and (2) lens change evaluation were performed. Carried out. The results are shown in Table 1.

The elongation and Young's modulus of the adhesive layers used in Examples 1 and 2 and Comparative Examples 1 to 7 were evaluated according to JIS K6251 as described above. The results are summarized in Table 1.
In Table 1, the case where the polyurethane contains an ester bond is shown in the “polymerization unit” column as “ester-based”, the case where an ether bond is included as “ether-based”, and the case where the carbonate bond is included as “carbonate-based”.
In Table 1, when the polyurethane contains an aromatic group, “present” is described in the “presence / absence of aromatic group” column, and the case where the aromatic group is not contained is described as “none”. In addition, when an aromatic group is contained, it corresponds to what is called an aromatic polyurethane, and when an aromatic group is not contained, it corresponds to what is called an aliphatic polyurethane.

As shown in Table 1 above, in Examples 1 and 2, which are the optical elements of the present invention, the adhesiveness of the functional film was excellent, and the occurrence of warpage was also suppressed.
On the other hand, in Comparative Examples 1 to 7 in which the adhesive layer does not satisfy the predetermined requirements, the adhesion of the functional film is inferior and / or a large warp occurs.

DESCRIPTION OF SYMBOLS 10 Optical element 12 Lens base material 14 Adhesive layer 16 Functional film

Claims (4)

An optical element comprising a lens substrate, an adhesive layer disposed on the lens substrate, and a functional film disposed on the adhesive layer,
The adhesive layer includes an ester-based polyurethane;
The elongation of the adhesive layer is 1050 to 1400%,
An optical element having a Young's modulus of the adhesive layer of 400 N / mm ² or less.   The optical element according to claim 1, wherein the polyester urethane contains an aromatic group.   The optical element according to claim 1, wherein the adhesive layer is formed from a composition containing an ester-based polyurethane latex. It is a manufacturing method of the optical element according to claim 3,
A coating film forming step of coating the composition on the surface of the lens substrate to form a coating film,
A laminating step of bonding a functional film on the coating film;
The manufacturing method of an optical element provided with the heating process which heat-processes after the said lamination process.