JP4427216B2 - Adhesive, method for connecting objects to be adhered, and optical device - Google Patents

Description

【００２９】
＜比較例１＞
ゴム成分を添加しない以外は、実施例２〜７と同じ条件で比較例２の接着剤を作製した。
【００３０】
＜比較例２、３＞
アクリルオリゴマーとして、単独重合させた場合に得られるポリマーの伸び率が１５０％未満であるアクリルオリゴマー（サートマー（株）社製の商品名「ＣＮ９８０」）を用い、上記表１に記載した配合比率で比較例２、３の接着剤を作製した。尚、比較例２、３で用いたアクリルオリゴマーは、ウレタンアクリレートの低重合体であり、単独重合させた場合に得られるポリマーの伸び率は６３％であった。
これら実施例１〜７、比較例１〜３の接着剤を用いて下記に示す「線膨張係数」、「弾性」、「信頼性試験」、「伸び率」各評価試験を行った。
【００３１】
〔伸び率〕
実施例１〜７、比較例１〜３の接着剤を剥離紙上に塗布し、塗布層を形成し、ランプ出力１２０Ｗ／ｃｍのメタルハライドランプを用いて、照度２００ｍＷ／ｃｍ²、積算光量３００ｍＪ／ｃｍ²の紫外線を照射して硬化させた後、硬化した接着剤を剥離紙から剥離し、１０種類のフィルム状試験片をそれぞれ作製した。これら１０種類の試験片を用いて、上述したようにＪＩＳ Ｋ６２５１の「引張り試験」の方法に準じて試験片の伸び率を測定し、得られた伸び率（％）を上記表１にそれぞれ記載した。
【００３２】
〔線膨張係数〕
上記「伸び率」試験と同じ工程で１０種類の試験片を作製し、それらの試験片に所定の荷重を加えた状態で初期長さＬを測定した後、測定雰囲気の温度を２５℃から８５℃まで上昇させて試験片の温度上昇による長さの増加量ｄＬを測定した。長さの増加量ｄＬと、温度の変化量ｄＴと、試料片の初期長さＬとをそれぞれ下記式（１）に当てはめ、線膨張係数ｂを求めた。
式（１）：ｂ＝（ｄＬ／ｄＴ）／Ｌ
得られた線膨張係数（×１０^-5／Ｋ）を上記表１にそれぞれ記載した。
【００３３】
〔戻り率〕
上記「線膨張係数」試験で作製した試験片に１ｇの荷重を加えた状態で−４０℃まで冷却する冷却処理と、８５℃まで昇温する加熱処理とを繰り返し行い、−４０℃のときと８５℃のときの長さを測定した。
初期状態の温度は２５℃の室温であり、最初に冷却処理を行った。
【００３４】
第１回目の冷却処理のとき(２５℃から−４０℃まで冷却したとき)の試験片の長さＰ₁と、第２回目、第３回目の冷却処理(８５℃から−４０℃まで冷却したとき)の試験片の長さＰ₂、Ｐ₃と、第１回目、第２回目の加熱処理のとき(−４０℃から８５℃まで加熱したとき)の試験片の長さＱ₁、Ｑ₂を測定し、低温時戻り率Ｒ₁、Ｒ₂(％)と、高温時戻り率Ｓ₁（％）を、下記式、
Ｒ₁ ＝ （Ｐ₂−Ｐ₁）／Ｐ₁×１００
Ｒ₂ ＝ （Ｐ₃−Ｐ₁）／Ｐ₁×１００
Ｓ₁ ＝ （Ｑ₂−Ｑ₁）／Ｑ₁×１００
によって求めた。
尚、１回の加熱処理と１回の冷却処理に要する時間の合計は３０分間であった。戻り率の値が低いほど、試料片の弾性は高いことを示している。
【００３５】
〔信頼性試験〕
白板ガラスからなる第一の貼着対象物１１に実施例１〜７、比較例１〜３の１０種類の接着剤をスピンコート法によって塗布して塗布層１４を形成し、該塗布層１４に第二の貼着対象物１７であるＰＭＭＡ樹脂フィルムを密着させた後、上記「伸び率」試験と同じ照射条件で紫外線を照射し、積層体１０からなる１０種類の試験片を作製した。これら１０種類の試験片を、「戻り率」と同じ条件で冷却処理と加熱処理とを繰り返しながら観察した。
【００３６】
加熱冷却処理が４００時間未満で接着剤層１５の剥がれやクラック（亀裂）等が観察された場合を「ＮＧ」、４００時間未満では外観の変化が起こらなかったものを「ＯＫ」として評価した。評価結果と外観変化が確認されたときの時間とを上記表１に記載した。
【００３７】
上記表１から明らかなように、本発明実施例１〜７は、硬化した後の伸び率が２００％以上であり、線膨張係数も大きく、充分な柔軟性を有していることがわかる。また、実施例１〜７では、戻り率も充分に低く、硬化後の接着剤が充分な弾性を有していることがわかる。
また信頼性試験の結果から明らかなように、柔軟性と弾性を併せ持つ実施例１〜７の接着剤では、比較例１〜３に比べて温度変化による耐久性が高い。
【００３８】
これらの中でも、ゴム成分の添加量が０．５重量部以上１５重量部以下である実施例１〜６は、ゴム成分の添加量が０．１重量部である実施例７に比べて戻り率が低く、信頼性試験においても高い結果が得られた。
他方、実施例２〜７と同じ重合性成分を含有するが、ゴム成分を含有しない比較例１の場合、線膨張係数や伸び率の結果は実施例１〜７と同程度であったが、各温度における戻り率が高かった。
【００３９】
また、ゴム成分を含有するが、アクリルオリゴマーの単独重合させた場合に得れられるポリマーの伸び率が１５０％未満である比較例２、３では、弾性試験の戻り率の値は実施例１〜７と同程度に低かったが、線膨張係数や伸び率の値が低くかった。線膨張係数等で示される柔軟性や、戻り率で示される弾性のいずれかが充分ではない比較例１〜３では、信頼性試験の結果も悪く、比較例１では２００時間で接着剤層の剥がれが見られ、比較例２、３ではそれぞれ１００時間で接着剤層にクラックが見られた。
【００４０】
尚、単独重合させた場合に得られるポリマーの伸び率が８１％であるアクリルオリゴマー（サートマー（株）社製の商品名「ＣＮ９８１」）を用いた以外は比較例２、３と同じ条件で試験片を作製したところ、比較例２、３と同様に線膨張係数や伸び率の値が低かった。
【００４１】
これらのことから、本発明の接着剤は、特定の重合性成分を用いることによって硬化後の伸び率や線膨張係数が高く、ゴム成分が添加されることによって硬化後に適度な弾性を有し、結果、信頼性が高くなっていることが確認された。
【００４２】
以上は、アクリルモノマーとしてフェノキシエチルアクリレートを用いる場合について説明したが、本発明はこれに限定されるものではなく、例えば、テトラヒドロフルフリルアクリレート等種々のアクリレートを用いることができ、これらのアクリレートを単独で用いても良いし、２種類以上混合させたものを用いてもよい。
【００４３】
また、アクリルオリゴマーもウレタンアクリレートの低重合体に限定されるものではなく、単独重合させた場合に得られるポリマーの伸び率が１５０％以上であれば、エステルアクリレート、エポキシアクリレート、メラミンアクリレート等種々のアクリレートの低重合体を用いることができる。
また、光重合開始剤も特に限定されるものではない。
【００４４】
以上は、ゴム成分としてニトリルブタジエンゴムを用いる場合について説明したが、ニトリルブタジエンゴム以外にも、例えば、天然ゴム、イソプロピレンゴム、ブタジエンゴム、１、２ポリブタジエンゴム、スチレンブタジエンゴム、クロロプレンゴム、ブチルゴム等種々のゴムを用いることができる。これらのゴム成分は単独で用いてもよいし、２種類以上混合したものを用いてもよい。
【００４５】
また、接着剤の貼着対象物を構成する材質はガラスや樹脂に限定されるものではない。貼着対象物を構成する樹脂は、ＰＭＭＡに限定されるものではなく、例えばポリエチレンテレフタレート、ポリカーボネ−ト、ノルボルネン樹脂ポリマー、トリアセチルセルロース、ポリオレフィン、ポリプロピレン等種々のものを用いることができる。
【００４６】
紫外線の照射方法も特に限定されるものではなく、紫外線を透過する貼着対象物を用いるのであれば、該貼着対象物に紫外線を照射することで、接着剤に紫外線を到達させることができる。
また、紫外線の照射条件も特に限定されるものではないが、紫外線の照射量が多くなりすぎると重合性成分とゴム成分とが過度に重合し、弾性率が失われるので、照度が５ｍＷ／ｃｍ²以上１０００ｍＷ／ｃｍ²以下であり、かつ積算光量が３００ｍＪ／ｃｍ²以上５０００ｍＪ／ｃｍ²以下であることが好ましい。
【００４７】
以上は、光学部品２５、２７であるレンズと支持部材とを貼り合わせる場合について説明したが、本発明はこれに限定されるものではなく、例えば、異なる材質からなる複数のレンズの貼り合わせや、受光素子やホログラムフィルム等種々の光学部品の貼り合わせに用いることができる。
【００４８】
また、貼着対象物は光学部品に限定されるものではなく、本発明の接続方法によれば、例えば、液晶表示装置に用いられる液晶パネルと偏光板とを貼り合わせたり、樹脂フィルムとガラス板とを貼り合わせることができる。例えば、可撓性を有する樹脂フィルムと、ガラス板とを貼り合わせれば、耐衝撃性に優れた複合ガラス板を得ることができる。
【００４９】
【発明の効果】
本発明によれば、接着剤が硬化した後の伸び率や線膨張係数が高く、かつ適度な弾性を有しているので、熱膨張率が異なる貼着対象物を貼り合わせた場合でも接着剤が剥離せず、貼着対象物の位置ずれも起こり難い。
【図面の簡単な説明】
【図１】(ａ)〜(ｄ)：本発明の接着剤を用いて貼着対象物の貼り合わせる工程を説明するための断面図
【図２】本発明の光学装置の一例を説明するための図
【符号の説明】
１０……光学装置
１４……接着剤（接着剤の塗布層）
１５、２６……接着剤層（硬化した接着剤）
１１……第一の貼着対象物
１７……第二の貼着対象物
２０……光学装置
２５……第一の光学部品
２７……第二の光学部品[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an adhesive, and more particularly to an adhesive that bonds a glass component and a resin component used in an optical device.
[0002]
[Prior art]
Conventionally, glass has been used as a material for optical components such as various lenses, support members, and light receiving elements used in optical devices for optical pickups, and UV curable adhesive is used for connecting optical components. Agents are widely used.
[0003]
By the way, resins such as polymethylmethacrylate (hereinafter abbreviated as PMMA) and polycarbonate are attracting attention as materials constituting each optical component. These resins are lighter than glass and easy to mold, and by using optical parts made of resin, the entire optical device can be reduced in size and weight, and the manufacturing cost is low.
Therefore, the material of optical components is shifting from glass to resin, and at present, optical components made of glass and optical components made of resin are often mixed in one optical device.
[0004]
However, since the thermal expansion coefficient differs between resin such as PMMA and glass, when the optical component made of resin and the optical component made of glass are bonded together with an adhesive, the expansion occurs when the temperature around the optical device rises. The optical component may be peeled off from the adhesive due to the stress caused by the difference in rate.
[0005]
[Problems to be solved by the invention]
The present invention was created to solve the above-described disadvantages of the prior art, and is to provide an adhesive having a high linear expansion coefficient and appropriate elasticity.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the invention described in claim 1 includes a polymerizable component, a rubber component, and a photopolymerization initiator, and the polymerizable component and the rubber component are polymerized by irradiation with ultraviolet rays. The polymerizable component contains phenoxyethyl acrylate which is an acrylic monomer and an acrylic oligomer which is a low polymer of urethane acrylate, and the rubber component contains nitrile butadiene rubber . In a state after polymerization by ultraviolet irradiation at an illuminance of 200 mW / cm ² and an integrated light amount of 300 mJ / cm ² , in tensile cutting, the distance L ₁ between the marked lines at the time of cutting and the distance L between the marked lines before tensioning _{From 0} , the following formula:
N = (L ₁ −L ₀ ) / L ₀ × 100
In the obtained elongation N (%) is not less than 200%, the elongation N (%) of the polymer obtained when the acrylic oligomer was homopolymerization is an adhesive Ru der least 150%.
Invention of Claim 2 is an adhesive agent of Claim 1, Comprising: The addition amount of the said nitrile butadiene rubber with respect to 100 weight part of said polymeric components is an adhesive agent which is 0.5 weight part or more.
The invention described in claim 3 is a method for connecting an object to be adhered, wherein the first object to be adhered made of glass and the second object to be adhered made of resin are defined in claim 1 or claim. The sticking target object which has the process of closely_contact | adhering via the application layer which consists of an adhesive agent of any one of 2, and the process of irradiating the said application layer with an ultraviolet-ray and hardening the adhesive agent which comprises the said application layer. This is the connection method.
The invention of claim 4, wherein is an optical device, a first optical component made of glass, and a second optical component made of a resin, said second optical component and said first optical component Between the first optical component and the second optical component, wherein the adhesive according to any one of claims 1 and 2 is disposed, and the adhesive is in close contact with both the first optical component and the second optical component, An optical device in which the adhesive is cured by ultraviolet irradiation.
Invention of Claim 5 is an optical apparatus of Claim 4, Comprising: Resin which comprises said 2nd optical component is a group which consists of a polymethylmethacrylate, a polyethylene terephthalate, a polycarbonate, and a norbornene resin polymer. It is an optical device containing a more selected resin.
[0007]
In the present invention, “acrylic monomer” means both acrylate and methacrylate, and “acrylic oligomer” means a low polymer composed of one or both of acrylate and methacrylate.
[0008]
The present invention is configured as described above, and the acrylic oligomer and the acrylic monomer constituting the polymerizable component have a high flexibility such that the elongation percentage of the entire adhesive after curing is 200% or more. Moreover, the adhesive after hardening also has moderate elasticity by adding rubber | gum.
[0009]
Therefore, the stress caused by the difference in expansion coefficient when the objects to be bonded with each other having a large expansion coefficient are bonded together like glass and resin by the adhesive of the present invention is alleviated by the adhesive. Since the adhesive deformed by the stress is restored by elasticity, the position of the bonded object to be bonded does not shift.
[0010]
Moreover, since the above adhesives have high adhesiveness with respect to resin and glass, an adhesive is hard to peel off from a sticking target object. Various additives such as a colorant can be added to the adhesive of the present invention. Moreover, the adhesive of this invention has high transparency of the hardened | cured material after hardening | curing in the state in which the coloring agent is not added.
[0011]
In the present invention, the “elongation rate” is “elongation at break” described in “tensile test” of JIS K6251 and was measured by the following method.
Using a metal halide lamp with a lamp output of 120 W / cm, the adhesive or oligomer that is the object to be measured is irradiated with ultraviolet rays with an illuminance of 200 mW / cm ² and an integrated light amount of 300 mJ / cm ² , and cured completely to form a film. After obtaining an object (film thickness of about 0.5 mm), a test piece was punched with a dumbbell No. 4 mold.
[0012]
Measure the distance between the marked lines at the time of cutting under the conditions described in “Tensile test method” of JIS K6251, and measure the distance between marked lines before tension from the distance L ₁ between the marked lines at the time of cutting. ₀ was subtracted, and the distance L ₀ between the pre-tension lines was further subtracted from that value and multiplied by 100 to obtain the elongation ((L ₁ −L ₀ ) / L ₀ × 100, unit:%).
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The manufacturing method of the adhesive of this invention is demonstrated below.
First, an acrylic oligomer having a polymer elongation of 150% or more obtained when homopolymerized is prepared, and the acrylic oligomer and acrylic monomer are mixed to obtain a polymerizable component.
[0014]
Next, a photopolymerization initiator and a rubber component are added to and mixed with the polymerizable component to produce the adhesive of the present invention.
This adhesive is in a liquid state at normal temperature under the condition where it is not irradiated with ultraviolet rays, and has high transparency to visible light and near infrared rays.
[0015]
Next, the process of manufacturing the optical device of the present invention using the above adhesive will be described.
The code | symbol 11 of Fig.1 (a) has shown the transparent 1st sticking target object which consists of glass. The adhesive prepared in the above step is applied to the surface of the first object 11 to form an adhesive coating layer 14 (FIG. 1B).
[0016]
Next, a transparent second sticking object 17 made of a resin film is pressed against the coating layer 14 (FIG. 1 (c)). In this state, when the ultraviolet light is irradiated toward the second sticking object 17 and the ultraviolet light passes through the transparent second sticking object 17 and reaches the coating layer 14, the adhesive constituting the coating layer 14. The polymerizable component of the agent is polymerized by ultraviolet rays to cure the adhesive.
[0017]
Reference numeral 15 in FIG. 1D denotes an adhesive layer made of a cured adhesive, and the first and second objects to be adhered 11 and 17 are bonded to each other by the adhesive layer 15.
The code | symbol 10 of FIG.1 (d) has shown the laminated body by which the 1st, 2nd sticking target objects 11 and 17 are bonded together.
[0018]
Next, an example of an optical device using the adhesive of the present invention will be described.
Reference numeral 20 in FIG. 2 indicates an example of an optical device. The optical device 20 includes a first optical component 25 that is a glass lens, and a second optical component 27 that is a support member and is made of a resin such as PMMA.
[0019]
The first optical component 25 is attached to the second optical component 27 via the adhesive layer 26 in the steps shown in FIGS. 1A to 1D, and the first optical component 25 is the first optical component 25. By being supported by the second optical component 27, it is held at a predetermined position.
[0020]
In order to read information on the optical recording medium 21 using the optical device 20, first, the laser light 21 is irradiated from the laser irradiation device 28 to the optical recording medium 22. The laser beam 21 reflected by the optical recording medium 22 enters the optical device 20 from the first optical component 25 of the optical device 20, and is detected by a light receiving element (not shown).
[0021]
In the optical recording medium 22, information is recorded as a concavo-convex pattern, and the intensity of the laser beam 21 reflected by the optical recording medium 22 changes depending on the concavo-convex pattern. By detecting this, information on the optical recording medium 22 can be read.
[0022]
In the adhesive of the present invention, by adding a specific acrylic oligomer and an acrylic monomer, the elongation rate of the cured adhesive layer 26 is as high as 200% or more, and the first and second having different linear expansion coefficients. Even when the second optical components 25 and 27 are heated and expanded, the stress caused by the difference in expansion coefficient is absorbed and alleviated by the cured adhesive layer 26, and therefore the first and second optical components 25. 27 are not peeled off from the adhesive layer 26.
[0023]
Further, since the adhesive layer 26 exhibits appropriate elasticity due to the addition of the rubber component, even when the adhesive layer 26 is deformed due to an external physical impact or a temperature change, the adhesive layer 26 is not elastic. Restore.
[0024]
Accordingly, the first optical component 25 attached to the second optical component 27 via the adhesive layer 26 is always held at a predetermined position, so that the focus of the laser light 21 incident from the first optical component 25 is increased. Deviations in distance and image formation are prevented.
[0025]
【Example】
<Example 1>
70 parts by weight of phenoxyethyl acrylate, an acrylic monomer, is added to 30 parts by weight of an acrylic oligomer (trade name “CN966J75” manufactured by Sartomer Co., Ltd.) having an elongation of 150% or more when homopolymerized. And a polymerizable component composed of an acrylic monomer and an acrylic oligomer was prepared.
The acrylic oligomer used here was a low polymer of urethane acrylate, and the elongation percentage of the polymer obtained when homopolymerized was 238%.
[0026]
Next, 2 parts by weight of a nitrile butadiene rubber as a rubber component and a trade name “Irgacure 184” manufactured by Nagase Sangyo Co., Ltd. as a radical photopolymerization initiator are added to 100 parts by weight of the polymerizable component. By mixing, a liquid and transparent adhesive of Example 1 was obtained.
[0027]
<Examples 2 to 7>
The adhesives of Examples 2 to 7 under the same conditions as in Example 1 except that the addition amount of the acrylic monomer and acrylic oligomer and the addition amount of the rubber component used in Example 1 were changed as shown in Table 1 below. Was made.
[0028]
[Table 1]

[0029]
<Comparative Example 1>
An adhesive of Comparative Example 2 was produced under the same conditions as in Examples 2 to 7 except that no rubber component was added.
[0030]
<Comparative Examples 2 and 3>
As an acrylic oligomer, an acrylic oligomer (trade name “CN980” manufactured by Sartomer Co., Ltd.) having an elongation rate of less than 150% when obtained by homopolymerization is used, and the blending ratio described in Table 1 above is used. The adhesives of Comparative Examples 2 and 3 were prepared. The acrylic oligomer used in Comparative Examples 2 and 3 was a low polymer of urethane acrylate, and the elongation percentage of the polymer obtained when homopolymerized was 63%.
Using the adhesives of Examples 1 to 7 and Comparative Examples 1 to 3, the following “linear expansion coefficient”, “elasticity”, “reliability test”, and “elongation ratio” evaluation tests were performed.
[0031]
〔Growth rate〕
The adhesives of Examples 1 to 7 and Comparative Examples 1 to 3 were applied onto release paper to form a coating layer, and using a metal halide lamp with a lamp output of 120 W / cm, an illuminance of 200 mW / cm ² and an integrated light amount of 300 mJ / cm After curing by irradiating with ultraviolet rays of ² , the cured adhesive was peeled off from the release paper, and 10 types of film-like test pieces were produced. Using these 10 kinds of test pieces, the elongation percentage of the test pieces was measured according to the method of “tensile test” of JIS K6251 as described above, and the obtained elongation percentages (%) are shown in Table 1 above. did.
[0032]
[Linear expansion coefficient]
Ten types of test pieces were prepared in the same process as the “elongation rate” test, and the initial length L was measured with a predetermined load applied to the test pieces. Then, the temperature of the measurement atmosphere was changed from 25 ° C. to 85 ° C. The amount of increase dL in length due to the temperature rise of the test piece was measured by raising the temperature to ° C. The linear expansion coefficient b was obtained by applying the length increase dL, the temperature change dT, and the initial length L of the sample piece to the following equation (1).
Formula (1): b = (dL / dT) / L
The obtained linear expansion coefficients (× 10 ⁻⁵ / K) are shown in Table 1 above.
[0033]
[Return rate]
When the test piece prepared in the above “linear expansion coefficient” test is subjected to a cooling process of cooling to −40 ° C. with a 1 g load applied and a heating process of raising the temperature to 85 ° C., and at −40 ° C. The length at 85 ° C. was measured.
The temperature in the initial state was room temperature of 25 ° C., and the cooling treatment was first performed.
[0034]
Test piece length P ₁ during the first cooling process (when cooled from 25 ° C. to −40 ° C.) and the second and third cooling processes (cooled from 85 ° C. to −40 ° C. ) Test piece lengths P ₂ and P _3, and test piece lengths Q ₁ and Q _{2 during the first} and _second heat treatments (when heated from −40 ° C. to 85 ° C.) The low temperature return rate R ₁ , R ₂ (%) and the high temperature return rate S ₁ (%)
R ₁ = (P ₂ −P ₁ ) / P ₁ × 100
R ₂ = (P ₃ −P ₁ ) / P ₁ × 100
S ₁ = (Q ₂ −Q ₁ ) / Q ₁ × 100
Sought by.
The total time required for one heat treatment and one cooling treatment was 30 minutes. The lower the return rate value, the higher the elasticity of the sample piece.
[0035]
〔Reliability test〕
Ten kinds of adhesives of Examples 1 to 7 and Comparative Examples 1 to 3 are applied to the first sticking object 11 made of white plate glass by a spin coat method to form a coating layer 14. After the PMMA resin film as the second object to be adhered 17 was adhered, ultraviolet rays were irradiated under the same irradiation conditions as in the “elongation rate” test, and 10 types of test pieces made of the laminate 10 were produced. These ten kinds of test pieces were observed while repeating the cooling treatment and the heat treatment under the same conditions as the “return rate”.
[0036]
The case where peeling or cracking (cracking) of the adhesive layer 15 was observed when the heating and cooling treatment was performed for less than 400 hours was evaluated as “NG”, and the case where the change in appearance did not occur after 400 hours was evaluated as “OK”. Table 1 shows the evaluation results and the time when the appearance change was confirmed.
[0037]
As is clear from Table 1 above, Examples 1 to 7 of the present invention have an elongation rate after curing of 200% or more, a large linear expansion coefficient, and sufficient flexibility. Moreover, in Examples 1-7, a return rate is also low enough, and it turns out that the adhesive agent after hardening has sufficient elasticity.
Further, as is clear from the results of the reliability test, the adhesives of Examples 1 to 7 having both flexibility and elasticity have higher durability due to temperature changes than Comparative Examples 1 to 3.
[0038]
Among these, Examples 1-6 in which the addition amount of the rubber component is 0.5 parts by weight or more and 15 parts by weight or less are compared with Example 7 in which the addition amount of the rubber component is 0.1 parts by weight. And a high result was obtained in the reliability test.
On the other hand, in the case of Comparative Example 1 which contains the same polymerizable component as in Examples 2 to 7, but does not contain a rubber component, the results of the linear expansion coefficient and elongation rate were similar to those in Examples 1 to 7, The return rate at each temperature was high.
[0039]
Moreover, in Comparative Examples 2 and 3 which contain a rubber component but the elongation percentage of the polymer obtained when the acrylic oligomer is homopolymerized is less than 150%, the value of the return rate of the elastic test is as in Examples 1 to 3. Although it was as low as 7, the linear expansion coefficient and elongation rate were low. In Comparative Examples 1 to 3, in which either the flexibility indicated by the linear expansion coefficient or the elasticity or the elasticity indicated by the return rate is not sufficient, the result of the reliability test is also bad. Peeling was observed, and in Comparative Examples 2 and 3, cracks were observed in the adhesive layer in 100 hours.
[0040]
The test was performed under the same conditions as in Comparative Examples 2 and 3 except that an acrylic oligomer (trade name “CN981” manufactured by Sartomer Co., Ltd.) having an elongation of 81% when homopolymerized was used. When a piece was produced, the linear expansion coefficient and elongation were low as in Comparative Examples 2 and 3.
[0041]
From these, the adhesive of the present invention has a high elongation rate and linear expansion coefficient after curing by using a specific polymerizable component, and has an appropriate elasticity after curing by adding a rubber component, As a result, it was confirmed that the reliability was high.
[0042]
The above describes the case where phenoxyethyl acrylate is used as an acrylic monomer, but the present invention is not limited to this, and various acrylates such as tetrahydrofurfuryl acrylate can be used. May be used, or a mixture of two or more types may be used.
[0043]
In addition, the acrylic oligomer is not limited to a low polymer of urethane acrylate, and various polymers such as ester acrylate, epoxy acrylate, and melamine acrylate can be used as long as the elongation rate of the polymer obtained by homopolymerization is 150% or more. A low polymer of acrylate can be used.
Also, the photopolymerization initiator is not particularly limited.
[0044]
The above describes the case where nitrile butadiene rubber is used as the rubber component, but besides nitrile butadiene rubber, for example, natural rubber, isopropylene rubber, butadiene rubber, 1, 2 polybutadiene rubber, styrene butadiene rubber, chloroprene rubber, butyl rubber Various rubbers can be used. These rubber components may be used alone or in combination of two or more.
[0045]
Moreover, the material which comprises the adhesive sticking target object is not limited to glass or resin. The resin constituting the object to be attached is not limited to PMMA, and various materials such as polyethylene terephthalate, polycarbonate, norbornene resin polymer, triacetyl cellulose, polyolefin, polypropylene, and the like can be used.
[0046]
The method of irradiating ultraviolet rays is not particularly limited, and if a sticking target that transmits ultraviolet rays is used, the ultraviolet rays can reach the adhesive by irradiating the sticking target with ultraviolet rays. .
Further, the irradiation condition of ultraviolet rays is not particularly limited, but if the irradiation amount of ultraviolet rays is too large, the polymerizable component and the rubber component are excessively polymerized and the elastic modulus is lost, so that the illuminance is 5 mW / cm. ² above 1000 mW / cm ² or less, and is preferably integrated light quantity is 300 mJ / cm ² or more 5000 mJ / cm ² or less.
[0047]
The above has described the case where the lenses that are the optical components 25 and 27 and the support member are bonded together, but the present invention is not limited to this, for example, bonding of a plurality of lenses made of different materials, It can be used for bonding various optical components such as a light receiving element and a hologram film.
[0048]
Further, the object to be attached is not limited to an optical component. According to the connection method of the present invention, for example, a liquid crystal panel and a polarizing plate used in a liquid crystal display device are bonded together, or a resin film and a glass plate are bonded. Can be pasted together. For example, if a resin film having flexibility and a glass plate are bonded together, a composite glass plate having excellent impact resistance can be obtained.
[0049]
【The invention's effect】
According to the present invention, since the elongation and the linear expansion coefficient after the adhesive is cured are high and have an appropriate elasticity, the adhesive can be used even when the objects to be adhered having different thermal expansion coefficients are bonded together. Does not peel off, and the positional displacement of the object to be stuck is unlikely to occur.
[Brief description of the drawings]
FIGS. 1A to 1D are cross-sectional views for explaining a process of bonding an object to be bonded using the adhesive of the present invention. FIG. 2 illustrates an example of an optical apparatus of the present invention. Figure [Explanation of symbols]
10: Optical device 14: Adhesive (adhesive coating layer)
15, 26 ... Adhesive layer (cured adhesive)
DESCRIPTION OF SYMBOLS 11 ... 1st sticking object 17 ... 2nd sticking object 20 ... Optical apparatus 25 ... 1st optical component 27 ... 2nd optical component

Claims (5)

An adhesive comprising a polymerizable component, a rubber component, and a photopolymerization initiator, and configured to polymerize the polymerizable component and the rubber component by irradiation with ultraviolet rays,
The polymerizable component contains a phenoxyethyl acrylate acrylic monomer, an acrylic oligomer is a low polymer of urethane acrylate, wherein the rubber component contains a nitrile-butadiene rubber,
In the state after polymerization by ultraviolet irradiation at an illuminance of 200 mW / cm ² and an integrated light amount of 300 mJ / cm ² , in tensile cutting, from the distance L ₁ between marked lines at the time of cutting and the distance L ₀ between marked lines before tension. , The following formula,
N = (L ₁ −L ₀ ) / L ₀ × 100
The elongation rate N (%) obtained in the step is 200% or more,
The elongation N (%) adhesive Ru der least 150% of the polymer obtained in the case where the allowed homopolymerizing acrylic oligomer.   The adhesive according to claim 1, wherein the amount of the nitrile butadiene rubber added to 100 parts by weight of the polymerizable component is 0.5 parts by weight or more. The first sticking object made of glass and the second sticking object made of resin are brought into close contact with each other via the coating layer made of the adhesive according to any one of claims 1 and 2. Process,
A method of connecting an object to be adhered, the method comprising: irradiating the coating layer with ultraviolet rays and curing an adhesive constituting the coating layer. A first optical component made of glass, and a second optical component made of a resin, between the first optical component and the second optical component one of the claims 1 or claim 2 An optical device in which the adhesive according to claim 1 is disposed, and the adhesive is cured by ultraviolet irradiation in a state where the adhesive is in close contact with both the first optical component and the second optical component.   5. The optical device according to claim 4, wherein the resin constituting the second optical component contains a resin selected from the group consisting of polymethyl methacrylate, polyethylene terephthalate, polycarbonate, and norbornene resin polymer.

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