JP2012032241A - Method for evaluating film adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method for more strictly, accurately, quickly and easily evaluating the adhesion of the coat film of a plastic lens.SOLUTION: This method of evaluating film adhesion includes: notching a coat film formed on a plastic lens base material; performing exposure to an ultraviolet ray and exposure to a dew condensation state to the notched coat film; and evaluating the change of the notch width of the coat film.

Description

  The present invention relates to a method for evaluating the adhesion of a thin film formed on a substrate surface. In particular, the present invention relates to a method for evaluating the adhesion of a film formed on the surface of a plastic lens substrate.

A coating film such as a hard coat layer, an antireflection film, or a water repellent film is provided on the surface of a plastic lens such as a plastic spectacle lens. It has been conventionally known that such a coating film is inspected for adhesion by, for example, a cross hatch test.
For example, the following Patent Document 1 describes that after a plastic lens is exposed to ultraviolet rays and condensation with a QUV tester, a coat film is cross-cut and an adhesive tape is applied. And the adhesiveness of a coating film is evaluated by investigating the presence or absence of film peeling after peeling an adhesive tape.

In particular, in the following Patent Document 1, a reference value is set for the change ΔYI of the YI value of the lens substrate before and after exposure to xenon light irradiation, and the value of ΔYI after exposure of the lens becomes this reference value. Defines the exposure conditions for the QUV test.
Thus, by determining the exposure conditions based on the ΔYI value, it is possible to set an exposure environment suitable for evaluating the deterioration of adhesion over time, and to accurately evaluate the adhesion of the film. ing.

JP 2008-96300 A

However, even if the result of the above-mentioned evaluation method is acceptable, the coating film may be peeled off when left in the outdoor natural environment for a long period of time and tested in accordance with the actual environment. It was.
In the conventional evaluation method described above, the coating film adhesion is more accurately evaluated by changing the exposure conditions. However, in this case, the more accurate the evaluation is, the more precisely the exposure conditions need to be set, and the test becomes complicated.

Further, in the conventional method, it is necessary to apply an adhesive tape after exposure to ultraviolet light or a high humidity environment, and to examine the state of film peeling after peeling. In this case, once this cross-hatch test is performed on the plastic lens, the state of the coating film changes due to the tension / peeling of the adhesive tape, and therefore the test cannot be continued using the plastic lens. .
Therefore, when changing the exposure time to ultraviolet light or a high humidity environment, it was necessary to prepare a new plastic lens each time and repeat the test many times.
Further, in order to examine the decrease in adhesion over time according to the exposure time, it is necessary to perform the test many times as described above, so that it takes time and the cost increases.

  The present invention has been made in view of the above problems, and provides an evaluation method capable of more strictly and accurately evaluating the adhesion of a coating film of a plastic lens and easily performing in a short time. Objective.

In order to solve the above-described problems, the film adhesion evaluation method according to the present invention includes a cutting process for cutting a coating film formed on a plastic lens substrate, and a method for applying ultraviolet rays to the coating film having the cutting. And an exposure step for performing exposure and exposure to condensation conditions.
And it is characterized by evaluating the change of the width | variety of the cut | notch of a coating film after this exposure process.

According to the film adhesion evaluation method of the present invention, the coating film of the plastic lens is cut in advance and exposed to ultraviolet rays and condensation. And the change of the width | variety of a notch after exposure is evaluated.
By examining the change in the cut width after exposure, the degree of deterioration of the coating film can be more accurately evaluated.
Moreover, the operation | work of sticking and peeling an adhesive tape conventionally is not required.

In the film evaluation method of the present invention, it is preferable to compare the maximum cut width of the coating film before the exposure process and the maximum cut width of the coat film after the exposure process.
In particular, by determining the ratio of the maximum cut width before and after the exposure process, the adhesion of the coating film is quantified by numerical values, and the adhesion of the coating film can be generalized and easily evaluated.

  The film evaluation method of the present invention can be applied to the evaluation of the adhesion of various films formed on a plastic lens substrate. The coat film to be evaluated may include, for example, a hard coat layer or a primer layer, and may further include an antireflection film, a photochromic film, or the like.

According to the present invention, the degree of deterioration of the coating film is evaluated by examining the change in the cut width after exposure. Because microscopic changes such as the cut width of the coating film are used, it is possible to evaluate the adhesion more accurately and accurately than the conventional macroscopic method for examining whether or not the coating film is peeled off when the adhesive tape is peeled off. it can.
In addition, it is not necessary to apply or peel off the adhesive tape, so that the test can be easily performed. Further, after measuring the width of cut, it can be continuously put into the exposure process again. Therefore, by repeating this, it becomes possible to examine the deterioration of the coating film over time according to the exposure time for one plastic lens.

FIG. 1A is an enlarged photograph showing the cut of the coating film immediately after the cutting process of the plastic lens of Example 1, and FIG. 1B is a diagram illustrating when the plastic lens was put into the exposure process in Example 1 and 12 cycles had elapsed. FIG. 1C is an enlarged photograph of the same notch portion after 21 cycles in the exposure process. FIG. 2A is an enlarged photograph showing the cut of the coating film immediately after the cutting process of the plastic lens of Example 2, and FIG. FIG. 2C is an enlarged photographic view of the same cut portion at the time of 21 cycles in the exposure process. FIG. 3A is an enlarged photograph showing the cut of the coating film immediately after the cutting process of the plastic lens of Example 3, and FIG. 3B is a diagram illustrating when the plastic lens was put into the exposure process in Example 3 and 12 cycles had elapsed. FIG. 3C is an enlarged photographic view of the same cut portion at the elapse of 21 cycles in the exposure process. In Example 1, Example 2, and Example 3, it is explanatory drawing which shows the relationship between the exposure time in an exposure process, and the largest notch width of a coating film.

Examples of the best mode for carrying out the present invention will be described below, but the present invention is not limited to the following examples. The description will be made in the following order.
1. Embodiment of Evaluation Method (1) Cut process (2) Exposure process (3) Evaluation Example

1. Embodiment of Evaluation Method The film adhesion evaluation method according to the present invention can be preferably applied to a plastic lens for spectacles, but can also be applied to other plastic lenses. The material of the lens substrate used for the plastic lens is not particularly limited.
Moreover, the adhesiveness of various coating films formed on a plastic lens substrate can be evaluated by the evaluation method of the present invention. The coat film may be configured to include a primer layer, a hard coat layer, an antireflection film, a water repellent film, or the like, or may include a photochromic film.

For example, when it is desired to confirm the adhesion performance of the hard coat layer, the evaluation method according to the present invention is applied to the coat film at the stage where the hard coat layer is formed on the lens substrate. A primer layer may be interposed between the lens substrate and the hard coat layer.
When it is desired to confirm the adhesion performance of the antireflection film, for example, the evaluation method according to the present invention is applied at the stage where the antireflection film is formed on the hard coat layer.
As described above, by appropriately applying the evaluation method according to the present invention at each stage of forming the coat film on the lens, it is also possible to individually confirm the adhesion of various layers and films. In addition, various layers and films may be formed independently, and the evaluation method according to the present invention may be applied.

Further, in the present invention, the step of cutting the coating film formed on the plastic lens substrate and the exposure of alternately exposing the ultraviolet ray and the exposure to the dew condensation state to the coating film cut by the cutting step. By passing through the process, the adhesion of the coating film is evaluated.
As described in detail below, in the present invention, the adhesiveness of the coating film can be evaluated by examining the change in the width of the cut in the coating film after the exposure process.

(1) Cutting step In the cutting step, a cut is made in the coating film to be evaluated formed on the lens substrate. For example, the coating film may be cross-cut at intervals of 1 mm based on JIS standard K5600-5-6 (ISO 2409: 1992) to form a right-angle lattice pattern for 100 squares. If the number of cuts is at least 1 or more, it is possible to evaluate the adhesion of the coating film, but if there are many cuts, the number of data for evaluating the deterioration state of the cuts can be increased.
Further, the plurality of cuts may be arranged in parallel, for example, without intersecting. However, it is preferable to divide the coat film into a plurality of independent regions as in the case of cross-cutting, for example, since deterioration such as peeling of the coat film is easily exposed at the cut position, and the adhesion of the coat film can be evaluated more strictly.

(2) Exposure process In the exposure process, the coating film cut by the cutting process is irradiated with ultraviolet rays and exposed to the dew condensation state to promote the deterioration of the coating film.
For example, a plastic lens that has undergone the above-described cutting process is placed in an accelerated weathering tester (QUV device) having an exposure adjustment function by ultraviolet irradiation and a temperature and humidity control function, and the ultraviolet irradiation cycle and the condensation cycle are repeated.

  As described above, in the present invention, the coating film is cut in advance and then exposed to ultraviolet rays and condensation. Thereby, at the time of exposure to ultraviolet irradiation or condensation, deterioration of the adhesion surface of the coat film is promoted directly from the exposed cut section. Therefore, a larger load can be easily applied to the coat film without changing the exposure environment. For this reason, it is possible to detect the adhesion performance of the coat film, which could not be differentiated in the past, and further improve the quality.

(3) Evaluation Then, the adhesiveness is evaluated by evaluating the deterioration of the cut state with respect to the plastic lens after the exposure process.
For example, it is preferable to measure the width of the notch. The method of the present invention for determining a microscopic change such as a cut width can detect the deterioration of the coating film more strictly than the conventional method for determining whether or not the coating film has been peeled off by the adhesive tape. Sex can be accurately evaluated.
In particular, it is desirable to evaluate the degradation state of the notch by comparing the maximum width of the notch before exposure to ultraviolet light or condensation with the maximum width of the notch after exposure.

In addition, by obtaining the ratio of the maximum depth of cut after exposure to the maximum depth of cut before exposure, it becomes possible to quantify and quantify the adhesion of the coating film, making it easier to adhere to different types of coating film. You can compare.
For example, if the ratio of the maximum notch width after exposure to the maximum notch width before exposure (maximum notch width after exposure / maximum notch width before exposure) exceeds 2 at an exposure time of 100 hours, It can be determined that the coating film to be formed has insufficient adhesion and is incompatible.

  In the past, for example, it has been investigated that a coating film is peeled off when an adhesive tape is applied to a cross-cut coating film and the adhesive tape is peeled off. However, in such a method, the peeling angle of the adhesive tape, the peeling speed, the tensile strength at the time of peeling, etc. tend to vary, and it is difficult to obtain accurate data.

In addition, the coated film after the adhesive tape is peeled off has various cross-cut areas such as an area where no peeling occurs, an area where partial peeling occurs, an area where the coating film is peeled off, etc. A state can exist.
In order to strictly evaluate the adhesion of the coating film, such operations as finely classifying these states or counting the number of states classified in each region (for example, JIS standards K5600-5-6, 8.3) Section) is necessary, and the work becomes complicated.

However, in the present invention, the cut width of the coating film that has been subjected to the exposure process is measured as it is, and the above-described tape affixing and peeling operations are not required.
In addition, the evaluation can be performed by only two numerical values, that is, the maximum cut width before exposure and the maximum cut width after exposure, and the adhesion of the coat film can be simply and easily investigated.

  Further, in the evaluation method of the present invention, the longer the exposure time to the ultraviolet rays or the dew condensation state, the more the difference in adhesion depending on the type of the coating film can be expressed. For example, it is desirable that the total exposure time to ultraviolet rays or dew condensation is 100 hours or more because the adhesion of the coating film can be more reliably evaluated.

2. Example <Example 1>
Below, the Example of the evaluation method of the film | membrane adhesiveness by this invention is described.
(1) Plastic lens base material The plastic lens base material has a refractive index of 1.71, a center thickness of 1.0 mm, a lens power of 0.00, and a lens base material having a polysulfide bond with a diameter of 80 mm (EYRY: manufactured by HOYA Corporation). ) Was used.

(2) Preparation of primer solution As a material for the primer layer, it is preferable to use a urethane-based material because of its high stress relaxation ability. Moreover, it is preferable to use the thermosetting urethane primer which has block type polyisocyanate and a polyol as a main component from the point of the pot life and the ease of hardening especially.
Specific examples of the block type polyisocyanate are based on various isocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, metaxylylene diisocyanate, and the terminal is phenol, ε-caprolactam, active methylene, MEK oxime, various amines. And the like blocked.

  Here, 32 parts by weight of Samprene IB-1700D manufactured by Sanyo Chemical Industries, Ltd. and 125 parts by weight of propylene glycol monomethyl ether are added to a stainless steel container, and 1.9 parts by weight of Coronate HL manufactured by Nippon Polyurethane Industry Co., Ltd. are stirred. Zirconium oxide sol fine particle solution (Nissan Chemical Industry Co., Ltd. product: NZS-30A) 53 parts by weight was added and mixed. Then, 0.1 part by weight of a silicone-based surfactant (L-7604: manufactured by Toray Dow Corning Co., Ltd.) was added and stirred for a whole day and night. Then, it filtered and created the primer layer forming coating liquid (henceforth A liquid). In addition, this A liquid is a thermosetting coating liquid.

(3) Preparation of hard coat solution Add 1045 parts by weight of γ-glycidoxypropyltrimethoxysilane and 200 parts by weight of γ-glycidoxypropylmethyldiethoxysilane to a stainless steel container, and add 0.01 mol / L with stirring. 299 parts by weight of hydrochloric acid were added. And the silane hydrolyzate was created by stirring this solution all day and night.

Further, 3998 parts by weight of a composite fine particle sol mainly composed of titanium oxide, zirconium oxide and silicon oxide was put into another container, and 4018 parts by weight of methyl cellosolve and 830 parts by weight of isopropanol were added and stirred and mixed. Then, 4 parts by weight of a silicone-based surfactant (L-7001: manufactured by Toray Dow Corning Co., Ltd.) and 100 parts by weight of aluminum acetylacetonate were added, and stirring was continued all day and night.
When the stirring was finished, it was mixed with the silane hydrolyzate described above and further stirred for a whole day and night. Then, the coating liquid for hard-coat film formation was formed by performing filtration.

(4) Formation of primer layer and hard coat layer The above-mentioned primer solution was applied to the above-mentioned plastic lens substrate while pulling up at 150 mm / min by the Dip method. And the primer liquid apply | coated by the heat processing for 100 degreeC for 20 minutes was hardened, and the primer layer with a film thickness of 1.5 micrometers was formed.
Moreover, the above-mentioned hard coat liquid was similarly applied to the plastic lens base material on which the primer layer was formed using the Dip method, and then the hard coat layer was formed by overheating.

(5) Formation of antireflection film A plastic lens on which a primer layer and a hard coat layer are formed is placed in a vapor deposition apparatus, heated to 85 ° C. while being evacuated, and subjected to ion gun treatment (carrier gas: oxygen, voltage: 400 eV, treatment time: 30 seconds). Next, after evacuation was continued until the degree of vacuum was 2 × 10 ⁻⁵ Torr, a deposition raw material was deposited by an electron beam heating method, and Ta ₂ O ₅ (0.12λ) / SiO ₂ (0.05λ from the hard coat layer side). ) / Ta ₂ O ₅ (0.25λ) / SiO ₂ (0.25λ), an antireflection film composed of four layers was formed to produce a plastic lens.

(6) Cut process
Based on JIS standard K5600-5-6 (ISO 2409: 1992), the above-mentioned plastic lens primer layer, hard coat layer, and coating film made of an antireflection film are cross-cut at 1 mm intervals, and a square lattice pattern is formed in 100 squares. Formed.
The cross-cut coat film was photographed with a microscope, and the photographed photograph was taken into a PC (personal computer) to measure the maximum cut width of the coat film.

(7) Exposure process The lens substrate with the coat film cross-cut is put into a QUV apparatus, and at a temperature of 45 ° C., ultraviolet irradiation (illuminance 0.20) is 4 hours, and condensation state (99% RH) 4 hours is one cycle. 21 cycles of exposure to UV and condensation conditions were performed.
Further, the coated film of the lens substrate that had undergone the exposure process was photographed with a microscope, and the photographed photograph was taken into a PC to measure the maximum cut width of the coated film.

<Example 2>
Add 32 parts by weight of Sanprene IB-2000 manufactured by Sanyo Chemical Industries Co., Ltd. and 125 parts by weight of propylene glycol monomethyl ether to a stainless steel container, and 1.9 parts by weight Coronate HL manufactured by Nippon Polyurethane Industry Co., Ltd. and zirconium oxide sol 53 parts by weight of a fine particle solution (manufactured by Nissan Chemical Industries, Ltd .: NZS-30A) was added and mixed.
Next, 0.1 part by weight of a silicone-based surfactant (L-7604: manufactured by Toray Dow Corning Co., Ltd.) is added to this mixed solution, and the mixture is stirred for a whole day and night, followed by filtration to obtain a thermosetting primer layer. A forming coating liquid (hereinafter referred to as B liquid) was formed.
And it evaluated similarly to Example 1 except having formed the primer layer using this coating liquid for primer layer formation.

<Example 3>
To a stainless steel container, 25 parts by weight of Permarin UA-150 manufactured by Sanyo Chemical Industry Co., Ltd. and 40 parts by weight of water are added, and 32 parts by weight of methanol, 61 parts by weight of diacetone alcohol and a titanium oxide fine particle solution (JGC Catalysts Chemical ( Co., Ltd .: Optlake 1130Z) 41 parts by weight was added and mixed.
Next, 0.1 parts by weight of a silicone-based surfactant (L-7604: manufactured by Toray Dow Corning Co., Ltd.) is added to this mixed solution, and the mixture is stirred for a whole day and night. A liquid (referred to as liquid C) was formed. In addition, this primer layer forming coating liquid (C liquid) is thermoplastic.
And it evaluated similarly to Example 1 except having formed the primer layer using this coating liquid for primer layer formation.

<Comparative Example 1>
The plastic lens on which the primer layer, hard coat layer, and antireflection film were formed was directly subjected to the QUV process, and a cross-hatch test was performed on the coating film of the plastic lens after the QUV process.
In the cross-hatch test, the coating film was cross-cut at 1 mm intervals based on JIS standard K5600-5-6 (ISO 2409: 1992) to form 100 square grid patterns. And after sticking an adhesive tape (cellophane tape: Nichiban Co., Ltd.) strongly on this cross-cut part, it performed by peeling off an adhesive tape rapidly. Moreover, it carried out like Example 1 except having investigated the presence or absence of peeling of the base film of a coating film after peeling an adhesive tape.

<Comparative example 2>
After the plastic lens primer layer, hard coat layer, and antireflection film were cross-cut as described above, the plastic lens was subjected to a QUV process. And after strongly sticking the adhesive tape (cellophane tape: manufactured by Nichiban Co., Ltd.) on the cross-cut part of the coating film after the QUV process, the adhesive tape is rapidly peeled off to check whether the base film of the coating film is peeled off or not The procedure was the same as in Comparative Example 1 except that the investigation was performed.

<Comparative Example 3>
After forming a primer layer, a hard coat layer, and a coating film made of an antireflection film on a plastic lens substrate, using steel wool cut to a 1.5 cm square size, applying a weight of 500 g, A range of 5 cm in width was rubbed 20 times.
Then, this plastic lens was subjected to the QUV process, and the same procedure as in Comparative Example 1 was performed except that the adhesive tape was attached to the rubbing portion of the coating film after the QUV process and was peeled off rapidly.

<Comparative example 4>
In the same manner as in Comparative Example 3, the plastic lens coat film was rubbed with steel wool and subjected to the QUV process.
Then, the coating film after the QUV step was cross-cut with 100 meshes at intervals of 1 mm, affixed with an adhesive tape, and then peeled off rapidly.

<Comparative Example 5>
The primer layer was formed in the same manner as in Comparative Example 1 except that the primer layer was formed using the primer layer forming coating solution in Example 2.

<Comparative Example 6>
The primer layer was formed in the same manner as in Comparative Example 2 except that the primer layer was formed using the primer layer forming coating solution in Example 2.

<Comparative Example 7>
The primer layer was formed in the same manner as in Comparative Example 3 except that the primer layer was formed using the primer layer forming coating solution in Example 2.

<Comparative Example 8>
The primer layer was formed in the same manner as in Comparative Example 4 except that the primer layer was formed using the primer layer forming coating solution in Example 2.

<Comparative Example 9>
The primer layer was formed in the same manner as in Comparative Example 1 except that the primer layer was formed using the primer layer forming coating solution in Example 3.

<Comparative Example 10>
The primer layer was formed in the same manner as in Comparative Example 2 except that the primer layer was formed using the primer layer forming coating solution in Example 3.

<Comparative Example 11>
The primer layer was formed in the same manner as in Comparative Example 3 except that the primer layer was formed using the primer layer forming coating solution in Example 3.

<Comparative Example 12>
The primer layer was formed in the same manner as in Comparative Example 4 except that the primer layer was formed using the primer layer forming coating solution in Example 3.

<Comparative Example 13>
Plastic lenses produced under the same conditions as in Examples 1 to 3 were prepared and left outdoors for 3 months, and an exposure test to the actual natural environment was performed.

First, Table 11 shows the evaluation results by the methods of Comparative Examples 1 to 12 described above.
The numbers in the table represent the number of areas where there was no peeling in each area of the coat film divided into hundreds by cross-cutting.
In Comparative Examples 3, 7, and 11, since the cross-cut was not performed, the number of portions where the coating film was peeled off was examined after the adhesive tape was peeled off.

In Comparative Examples 1, 5, and 9, the number of areas without peeling was 100, and it was confirmed that no film peeling occurred.
On the other hand, in Comparative Examples 2, 6, and 10, the number of non-peeled areas is 90, and a slight film peeling occurs. In Comparative Examples 2, 6, and 10, since the coating film was subjected to exposure to ultraviolet light and high humidity after cross-cutting, the exposed cross section exposed at the cut of the coating film is easily peeled off due to direct load. This is because.

In Comparative Examples 3, 7, and 11, no peeling of the coating film was observed. For this reason, in Table 1, the description is “OK”.
Further, in Comparative Examples 4, 8, and 12, the number of areas where there is no peeling is 99, and peeling is slightly caused.

  As described above, in the method of confirming the film peeling after the adhesive tape is applied and peeled off, although there are some differences depending on how the load is applied to the coat film, all the results are equivalent. For example, in the case where the number of non-peeling areas is 80 or more is used as an acceptance criterion for adhesion, the evaluation result indicates that there is no problem in the adhesion of the coat film regardless of which method is used.

  Further, as can be seen from Table 1, if the test method is the same, the number of areas where no peeling occurred is equal regardless of the material of the primer layer. That is, based on this result, the primer layer material does not affect the adhesion of the coating film.

On the other hand, in Comparative Example 13 in which plastic lenses using the liquid A, liquid B, and liquid C, respectively, as the raw material of the primer layer were placed outdoors for 3 months, film peeling or the like occurred in the plastic lens using liquid A or liquid B. No abnormalities were confirmed.
However, it was confirmed that in the plastic lens using the liquid C as the material for the primer layer, film peeling slightly occurred from the lens edge to the optical surface.

  That is, in the actual natural environment and use environment, the adhesion of the coat film varies greatly depending on the material type of the primer layer. It can be said that the gender difference is not detected.

On the other hand, the result of Examples 1-3 using the evaluation method by this invention is shown in FIGS.
FIG. 1A is an enlarged photograph of a cut film cut immediately after the cutting process in Example 1. FIG.
Moreover, FIG. 1B is an enlarged photograph of the same cut portion when 12 cycles (96 hours) have elapsed after the plastic lens after the cutting step in Example 1 was put into the exposure step.
Moreover, FIG. 1C is an enlarged photograph of the same cut portion when 21 cycles (168 hours) have elapsed after the plastic lens after the cutting step in Example 1 was put into the exposure step.

FIG. 2A is an enlarged photograph of the cut film cut immediately after the cutting process in Example 2. FIG.
Moreover, FIG. 2B is an enlarged photograph of the same notch portion after 12 cycles (96 hours) of the exposure process in Example 2.
Moreover, FIG. 2C is an enlarged photograph of the same notch portion after 21 cycles (168 hours) of the exposure process in Example 2.

FIG. 3A is an enlarged photograph of a cut film cut immediately after the cutting process in Example 3.
Moreover, FIG. 3B is an enlarged photograph of the same notch portion after 12 cycles (96 hours) of the exposure process in Example 3.
Moreover, FIG. 3C is an enlarged photograph of the same notch portion after 21 cycles (168 hours) of the exposure process in Example 3.

In Example 1 in which the liquid A was used as the material for the primer layer, the cut width was slightly increased after 21 cycles of the exposure process.
In Example 2 using the liquid B as the raw material for the primer layer, it was confirmed that the notch width hardly changed even after the exposure process of 21 cycles.
Further, in Example 3 using the liquid C as the primer layer raw material, the cut width was already widened at the time of 12 cycles, and the cut width was widened at the end of 21 cycles, which is more than three times that before exposure. It is also.

The maximum cut widths of the coating films in Examples 1 to 3 were measured immediately after the cutting process, when 6 cycles (48 hours) of the exposure process passed, 12 cycles (96 hours) of the exposure process passed, and 21 cycles (168 hours) passed. The results measured at each time are shown in FIG.
In FIG. 4, the horizontal axis is the time (hr) of charging into the exposure process, and the vertical axis is the ratio of the notch width W at each elapsed time of the exposure process to the notch width W ₀ immediately after the cutting process (W / W). ₀ ).
Symbol a is the case of the first embodiment, symbol b is the second embodiment, and symbol c is the third embodiment.

As shown in FIG. 4, in the symbol b of Example 2 using the liquid B as the primer layer material, the value of W / W ₀ is close to 1 even after 168 hours of 21 cycles, and the most notch is observed. There has been very little change.
Further, in the symbol a of Example 1 using the liquid A as the primer layer raw material, the value of W / W ₀ is about 1.3 after 21 cycles, and the maximum cut width is slightly increased.

On the other hand, in the symbol c of Example 3 using the liquid C as the primer layer material, the value of W / W ₀ is already about 1.8 at the end of 6 cycles (48 hours), and at the end of 21 cycles. , It is significantly larger than 3.5.
Further, as the exposure time to the exposure process is increased, the difference in W / W ₀ in Examples 1 to 3 is larger.

In Comparative Examples 1 to 12, which are conventional evaluation methods, the results were not significantly different as shown in Table 1, and the actual adhesion as shown in Comparative Example 13 could not be evaluated.
However, in Examples 1 to 3 according to the present invention in which the maximum cut width in the coating film before the exposure process and the cut width of the coat film after the exposure process are compared, the difference in the value of W / W ₀ appears remarkably. .
In particular, in Example 3 in which the liquid C was used as the material for the primer layer, the value of W / W ₀ was extremely increased as described above, and the adhesion of the coating film in which peeling occurred in Comparative Example 13 was weak. Can be detected.
That is, according to Examples 1 to 3, it is possible to identify the difference in the adhesion of the coat film depending on the material of the primer layer.

As described above, by comparing the width of the cut formed in the coating film before and after the exposure process, a difference in adhesion of the coating film, which cannot be evaluated by the conventional method, can be easily detected.
Therefore, the adhesion performance of the coating film can be evaluated more strictly and accurately, and a high-quality plastic lens can be provided.

In addition, since the evaluation can be performed only by comparing the maximum cut width, measurement is easy, and it is not necessary to classify the degree of peeling of each area divided into the bases as in the prior art.
In addition, since an operation of applying and peeling an adhesive tape on the cross-cut coat film is unnecessary, an error caused by a variation in an artificial operation is reduced.

Further, by obtaining the ratio of the maximum cut width before and after the exposure process, the adhesion of the coating film is quantified by numerical values, and the adhesion of the coating film can be generalized and easily evaluated.
For example, when the exposure time is 100 hours and the ratio W / W ₀ of the maximum cut width before and after the exposure process is 2 or more, it can be determined that the adhesion of the coat film is insufficient.

Here, an example is given in which the difference in the adhesion of the coat film is caused by the material type of the primer layer. This is only an example, and it is possible to detect and evaluate the difference in the same manner when other layers or films constituting the coat film are the cause.
In addition, by using the evaluation method according to the present invention, it is possible to effectively use it as a raw material selection means in liquid formulation in developing primer liquid, hard coat liquid, antireflection film and other functional films. Is possible.

The embodiments and examples of the plastic lens according to the present invention have been described above. The present invention is not limited to the above-described embodiment, and it is needless to say that the present invention includes various conceivable forms without departing from the gist of the present invention described in the claims.

Claims (3)

A cutting process for making a cut in the coating film formed on the plastic lens substrate;
An exposure step of exposing the cut film to ultraviolet light and exposure to condensation;
And evaluating the change in the cut width of the coat film after the exposure step.   The method for evaluating film adhesion according to claim 1, wherein the maximum cut width of the coat film before the exposure step is compared with the maximum cut width of the coat film after the exposure step.   The film adhesion evaluation method according to claim 2, wherein the coating film includes an antireflection film.