JP2013064075A - Liquid adhesive composition, optical member in which the composition is encapsulated, and method for manufacturing the optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid adhesive composition which improves followability to the difference in level between a printing ink layer and the surface of a transparent substrate, has excellent reworkability, and can be adapted to sticking in a vacuum state.SOLUTION: The liquid adhesive composition comprises: an energy ray-polymerizable urethane (meth)acrylate; an energy ray polymerization initiator; and a silicone oil having a crosslinkable substituent and a mass average molecular weight (Mw) of 400-5,000; wherein a viscosity at 25°C is 1,000-4,000 mPa s. In an optical member 1, the liquid adhesive composition 11 is encapsulated in a frame-shaped marginal part 14 disposed between a transparent front substrate 12 and a transparent conductive film 13.

Description

  The present invention relates to a liquid pressure-sensitive adhesive composition used for an optical member used in an image display device such as a touch panel, a liquid crystal display, and electronic paper, an optical member encapsulating the composition, and a method for producing the optical member.

  Conventionally, optical members used in image display devices such as touch panels, liquid crystal displays, and electronic paper have been widely used. The optical member includes a transparent base material such as glass and a transparent conductive film such as indium tin oxide (hereinafter also referred to as “ITO”). The transparent base material and the transparent conductive film are made of an adhesive composition. It is laminated via an adhesive layer.

  In order to enhance the visibility and impact resistance of the optical member, the pressure-sensitive adhesive composition contains an energy ray polymerization type urethane (meth) acrylate or epoxy acrylate and an energy ray polymerization initiator. . However, in recent years, a printing ink layer is formed on the peripheral portion of a transparent substrate such as glass in order to impart design properties to a mobile phone and a touch panel. Due to the presence of the printing ink layer, even if the optical member composed of the transparent base material / adhesive layer / transparent conductive film is irradiated with ultraviolet light, the ultraviolet light is not transmitted in the region in contact with the printing ink layer. Can be cured.

  In order to solve this problem, it has been proposed that a compound having an average of at least one hydrolyzable silyl group in one molecule is added to the pressure-sensitive adhesive composition (for example, see Patent Document 1). According to this, it is possible to avoid being uncured even in a portion that can be rapidly cured by ultraviolet light and is not exposed to ultraviolet light.

JP 2010-248347 A

  By the way, a level | step difference has arisen between the printing ink layer and the surface of a transparent base material, and the level | step difference followable | trackability which tracks this level | step difference is also requested | required with respect to an adhesive composition. Therefore, it is required to further reduce the viscosity of the pressure-sensitive adhesive composition. In particular, since the transparent conductive film is expensive, it is required to further improve the reworkability. Moreover, in order to prevent bubbles from entering the layer when the pressure-sensitive adhesive layer is formed, it is required that the transparent base material and the transparent conductive film can be bonded together in a vacuum state.

  The present invention has been made in view of the above circumstances, and the purpose thereof is to improve the followability of the step generated between the printing ink layer and the surface of the transparent substrate, and is excellent in reworkability, And it is providing the liquid adhesive composition which can respond also to the bonding in a vacuum state.

  The present inventor has made extensive studies to solve the above problems, and has an energy ray polymerization type urethane (meth) acrylate, an energy ray polymerization initiator, a crosslinkable substituent, and a mass average molecular weight. The surface of the printing ink layer and the transparent substrate is obtained by using a liquid pressure-sensitive adhesive composition containing (Mw) 400 to 5000 silicone oil and having a viscosity at 25 ° C. of 1000 mPa · s to 4000 mPa · s. The present invention has been completed by finding that it is excellent in both the followability and reworkability of the level difference generated between the two and in a vacuum state and can be applied. Specifically, the present invention provides the following.

  (1) The present invention comprises an energy ray polymerization type urethane (meth) acrylate, an energy ray polymerization initiator, a silicone oil having a crosslinkable substituent and having a mass average molecular weight (Mw) of 400 to 5,000. It is a liquid pressure-sensitive adhesive composition that has a viscosity at 25 ° C. of 1000 mPa · s or more and 4000 mPa · s or less.

  (2) Moreover, this invention is a liquid adhesive composition as described in (1) whose said crosslinkable substituent is an alkoxy group.

  (3) Moreover, this invention contains 10 mass parts or more and 100 mass parts or less of the said silicone oil with respect to 100 mass parts of said urethane (meth) acrylates, The liquid adhesive composition as described in (1) or (2) It is a thing.

  (4) In the present invention, the liquid pressure-sensitive adhesive composition according to any one of (1) to (3) is placed in a frame-shaped peripheral portion arranged between the transparent substrate and another substrate. It is the optical member enclosed.

  (5) Moreover, this invention is a combination of the said transparent base material and another base material is a transparent front substrate and a transparent conductive film, or is a transparent conductive film and a liquid crystal substrate as described in (4). It is an optical member.

  (6) Moreover, this invention is an optical member as described in (4) or (5) used for a touch panel.

  (7) Moreover, this invention applies the liquid adhesive composition in any one of (1) to (3) on one 1st base material selected from a transparent base material or another base material. A bonding step, a bonding step of bonding the other second substrate selected from the transparent substrate or the other substrate through the liquid pressure-sensitive adhesive composition, and above the second substrate. Or the liquid adhesive which irradiated the energy ray from the side of the said liquid adhesive composition, the liquid adhesive composition apply | coated to the periphery on the said 1st base material hardened | cured, and was applied to the other area | region And a temporary curing step in which the composition is in an uncured temporary curing state.

  (8) Moreover, this invention is a manufacturing method of the optical member as described in (7) which performs the said bonding process under reduced pressure.

  (9) Moreover, this invention further irradiates an energy beam from the said transparent base material side with respect to the said liquid adhesive composition after temporary hardening, and cures the said liquid adhesive composition (7) or (8 The manufacturing method of the optical member as described in 1).

  (10) Moreover, this invention is a manufacturing method of the optical member as described in (9) which further hardens | cures the said liquid adhesive composition by moisture and / or a heat | fever.

  According to the present invention, a liquid pressure-sensitive adhesive composition that enhances the followability of a step generated between a printing ink layer and the surface of a transparent substrate, is excellent in reworkability, and can be used for bonding in a vacuum state. Can provide things.

It is a schematic plan view of the optical member which concerns on this invention in case the combination of a transparent base material and another base material is a combination of a transparent front substrate and a transparent conductive film. It is a schematic sectional drawing seen from the A-A 'cross section in FIG.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. can do.

<Liquid adhesive composition>
The liquid pressure-sensitive adhesive composition of the present invention contains an energy beam polymerization type urethane (meth) acrylate, an energy beam polymerization initiator, and a silicone oil having a crosslinkable substituent.

[Energy ray polymerization type urethane (meth) acrylate]
The urethane (meth) acrylate is not particularly limited as long as it can be polymerized by irradiation with energy rays, and examples thereof include photoradical polymerizability, photocationic polymerizability, and photoanion polymerizability. Among these, a photo-radically polymerizable oligomer is preferable. This is because the curing speed is high, and a wide variety of compounds can be selected. Furthermore, physical properties such as adhesiveness before curing and peelability after curing can be easily controlled to desired ones. .

  The mass average molecular weight (Mw) of urethane (meth) acrylate is not particularly limited, but it is a liquid adhesive for use in bonding two kinds of base materials (for example, a transparent base material and a transparent conductive film) under reduced pressure. When the agent composition is used, it is preferably 10,000 or more. If the mass average molecular weight (Mw) is less than 10,000, urethane (meth) acrylate volatilizes under reduced pressure, and there is a possibility that it is not possible to cope with bonding in a vacuum state. The weight average molecular weight is a value in terms of polystyrene when measured by gel permeation chromatography (GPC).

  Examples of energy rays include rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X-rays and γ rays, electron beams, proton rays, and neutron rays. In view of the curing speed, the availability of the irradiation device, the price, etc., curing by ultraviolet irradiation is preferable.

  Examples of the pressure-sensitive adhesive composition include T-100, 110, 470, and 1000 manufactured by KSM.

[Energy beam polymerization initiator]
The pressure-sensitive adhesive composition of the present invention contains an energy beam polymerization initiator. By containing an energy ray polymerization initiator, the sensitivity of the urethane (meth) acrylate can be enhanced, so that it is possible to reduce the polymerization curing time by energy rays and the energy ray irradiation amount.

  The content of the polymerization initiator is not particularly limited as long as the radical chain reaction starts and proceeds, for example. Generally, the polymerization initiator is blended in such an amount that the absorbance at the maximum absorption wavelength of the polymerization initiator measured using a commercially available spectrophotometer is within the range of 0.4 to 0.5.

  Examples of the polymerization initiator include TPO, IRGACURE 184 (both manufactured by BASF Japan) and the like.

[Silicone oil having a crosslinkable substituent]
The pressure-sensitive adhesive composition of the present invention contains silicone oil. This silicone oil is used as a moisture curable oligomer. Therefore, silicone oil has a crosslinkable substituent. If it does not have a crosslinkable substituent, it will not be cured even when moisture is applied, and in the region that is in contact with the printing ink layer formed on the peripheral edge of the transparent substrate, energy rays cannot be transmitted and can be uncured. It is not preferable.

  The crosslinkable substituent is not particularly limited, and examples thereof include an alkoxy group exemplified by a methoxy group and an ethoxy group.

  By the way, as a moisture curable substance, a monofunctional monomer such as an acrylic monomer is known in addition to a silicone oil having a crosslinkable substituent. However, it is not preferable to use a monofunctional monomer because the monofunctional monomer volatilizes when the two types of base materials are bonded together under reduced pressure, and may not be compatible with bonding in a vacuum state. In this respect, the upper limit of the mass average molecular weight (Mw) of the silicone oil is preferably 5000 or less. When the mass average molecular weight (Mw) exceeds 5000, the viscosity of the liquid pressure-sensitive adhesive composition exceeds 4000 mPa · s, and it may not be possible to provide an appropriate level difference followability and an appropriate reworkability. The lower limit of the mass average molecular weight (Mw) of the silicone oil is not particularly limited, but the liquid adhesive is used for bonding two kinds of substrates (for example, a transparent substrate and a transparent conductive film) under reduced pressure. When using a composition, it is preferably 400 or more. When the mass average molecular weight (Mw) is less than 400, the silicone oil is volatilized when the two kinds of substrates are bonded together under reduced pressure, and there is a possibility that the bonding in a vacuum state cannot be supported.

  The silicone oil is preferably contained in an amount of 10 to 100 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate. If it is less than 10 parts by mass, it is not preferable because of insufficient curing. If it exceeds 100 parts by mass, the adhesiveness is inferior, which is not preferable.

  Specific examples of preferred alkoxy group-containing organosilane compounds include trade names, DC3074, DC3037, SR2402 (above, manufactured by Toray Dow Corning Silicone), trade names, KR9218, KR-213, KR510, X40-9227, Commercial products such as X40-9247, KR500, KR400, X40-9225, X40-9246, X40-9250 (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned.

  In addition, the pressure-sensitive adhesive composition of the present invention includes a silane coupling agent, a tackifier, a metal chelating agent, a surfactant, an antioxidant, and an ultraviolet absorber as long as the object of the present invention is not impaired. Various additives such as pigments, dyes, colorants, antistatic agents, antiseptics, antifoaming agents, wettability adjusting agents, and plasticizers can be blended.

[viscosity]
The upper limit of the viscosity at 25 ° C. of the liquid pressure-sensitive adhesive composition is preferably 4000 or less. If the viscosity exceeds 4000 mPa · s, it may not be possible to provide an appropriate level difference followability and an appropriate reworkability, which is not preferable. The lower limit of the viscosity at 25 ° C. of the liquid pressure-sensitive adhesive composition is not particularly limited, but the liquid pressure-sensitive adhesive is used for bonding two kinds of base materials (for example, a transparent base material and a transparent conductive film) under reduced pressure. When the agent composition is used, it is preferably 1000 mPa · s or more. When the viscosity is less than 1000 mPa · s, it is estimated that the mass average molecular weight (Mw) of the urethane (meth) acrylate and / or the silicone oil is too small, and as a result, the two kinds of substrates are bonded together under reduced pressure. In some cases, the urethane (meth) acrylate and / or the silicone oil volatilizes, and there is a possibility that it cannot be applied in a vacuum state.

<Method for producing liquid pressure-sensitive adhesive composition>
The manufacturing method of the liquid adhesive composition of this invention is not specifically limited, A conventionally well-known method can be used. For example, it can be produced by dissolving or dispersing the urethane (meth) acrylate, the energy beam polymerization initiator, the silicone oil, and various additives as required in an organic solvent. Although it does not specifically limit as an organic solvent, For example, toluene, methyl ethyl ketone, ethyl acetate, dimethylacetamide, these mixed solutions, etc. can be used conveniently.

<Optical member>
In the optical member of the present invention, the liquid pressure-sensitive adhesive composition is sealed between a transparent substrate and another substrate. And the combination of a transparent base material and another base material is a transparent front substrate and a transparent conductive film, or a transparent conductive film and a liquid crystal substrate. Moreover, since the hardened | cured material which hardened the said liquid adhesive composition has moderate viscoelasticity, it is suitable to use especially the optical member of this invention for a touchscreen. Below, although the case where the combination of a transparent base material and another base material is a combination of a transparent front substrate and a transparent conductive film is demonstrated, it can also be set as the combination of a transparent conductive film and a liquid crystal substrate.

  FIG. 1 shows a schematic plan view of the optical member 1 when the combination of a transparent base material and another base material is a combination of a transparent front substrate and a transparent conductive film. FIG. 2 is a schematic cross-sectional view seen from the A-A ′ cross-section in FIG. 1.

  In the transparent optical member 1, the liquid adhesive composition 11 described above is enclosed between the transparent front substrate 12 and the transparent conductive film 13. At that time, the liquid pressure-sensitive adhesive composition 11 is enclosed in a frame-shaped peripheral edge portion 14 disposed between the transparent front substrate 12 and the transparent conductive film 13. The cured product 14 is a cured product obtained by curing the liquid pressure-sensitive adhesive composition with energy rays, and is formed on the periphery on the first base material selected from the transparent front substrate 12 or the transparent conductive film 13. Yes. By providing the peripheral portion 14, high reworkability can be maintained as long as possible for a long time, and since the transparent front substrate 12 and the transparent conductive film 13 are bonded to each other at the peripheral portion 14, the inside of the peripheral portion 14 is inside. Even if it is liquid, the transparent front substrate 12 and the transparent conductive film 13 can be prevented from peeling off.

[Transparent front substrate 12]
The transparent front substrate 12 is disposed on the outermost layer of the transparent optical member 1. A printing ink layer 15 is formed on the peripheral edge of the transparent front substrate 12. The transparent front substrate 12 may be any material as long as it is used on the surface of the image display device, and may be glass or a transparent film.

[Transparent conductive film 13]
The transparent conductive film 13 includes a film base 13a and a metal oxide layer 13b formed on the film base 13a.

  The film substrate 13a may be any material as long as a conductive film such as an ITO film or a zinc oxide (AZO: Al—Zn—O) film is formed on a substrate film such as a polyester film. May be. The thickness of the film base 13a is preferably 25 μm to 250 μm. If it is less than 25 μm, it is not preferable because it is a thin film and its workability is poor and its durability is insufficient. If it exceeds 250 μm, it is not preferable in terms of cost, and since it is a thick film, the light transmittance is decreased, which is not preferable as an optical member.

The metal oxide layer 13b is formed as an electrode. Examples of the metal oxide include ZnO, TiO ₂ , CeO ₂ , Sb ₂ O ₅ , SnO ₂ , Y ₂ O ₃ , La ₂ O ₃ , ZrO ₂ , Al ₂ O ₃ , Nb ₂ O _5, etc. Not as long. The thickness of the metal oxide layer 13b is preferably 10 to 200 nm. When the thickness is less than 10 nm, a missing portion is generated as an electrode due to coating unevenness during layer formation, which is not preferable in that an appropriate current collecting effect may not be obtained. If it exceeds 200 nm, it is not preferable in that the cost increases.

  A metal electrode 16 for current collection is formed on a part of the metal oxide layer 13b. As long as the metal electrode 16 is an electrode of two kinds of metals having different ionization tendencies, an aluminum electrode is widely used for the positive electrode, and more ionized than aluminum for the negative electrode. Copper electrodes with a low tendency are widely used.

  The printing ink layer 15 and the metal electrode 16 are preferably formed at substantially the same position on the peripheral edge as viewed from the surface of the transparent front substrate 12. Thereby, the metal electrode 16 formed on the metal oxide layer 13b can be hidden, and the design of the optical member 1 and an information terminal device using the optical member 1 is enhanced.

  [Thickness of the pressure-sensitive adhesive layer comprising the liquid pressure-sensitive adhesive composition 11]

  The thickness of the pressure-sensitive adhesive layer made of the liquid pressure-sensitive adhesive composition 11 is preferably 50 μm or more and 300 μm or less. If the thickness is less than 50 μm, it may not be possible to provide an appropriate level difference followability, which is not preferable. On the other hand, if the thickness exceeds 300 μm, it may adversely affect optical characteristics such as light transmittance, which is not preferable.

[Liquid crystal substrate]
As described above, FIGS. 1 and 2 describe the case where the combination of the transparent base material and the other base material is a combination of the transparent front substrate 12 and the transparent conductive film 13. A combination of the conductive film 13 and a liquid crystal substrate (not shown) can also be used. The liquid crystal substrate may be any material as long as it is conventionally used.

<The manufacturing method of the optical member 1>
The optical member 1 of the present invention is manufactured by the following method. Here, a case where a bank portion (not shown) is provided will be described, but the bank portion is not an essential configuration.

  First, a frame-shaped bank portion is formed on one first base material selected from the transparent front substrate 12 or the transparent conductive film 13. In this step, first, the liquid adhesive composition is applied to the periphery on the first substrate. Then, an energy ray is irradiated with respect to a liquid adhesive composition from the upper side of the said liquid adhesive composition, and a liquid adhesive composition is hardened.

As the energy ray, light in a wavelength region of 200 to 450 nm is preferable, and light in a wavelength region of 300 to 450 nm is more preferable. The light source 24 is not particularly limited, and for example, a high pressure mercury lamp, an ultra high pressure mercury lamp, a carbon arc lamp, a mercury vapor arc, a fluorescent lamp, an argon glow lamp, a halogen lamp, an incandescent lamp, a low pressure mercury lamp, a flash UV lamp, a deep Examples thereof include a UV lamp, a xenon lamp, a tungsten filament lamp, and sunlight. Using these light sources 24, the liquid pressure-sensitive adhesive composition can be cured by irradiating light so that the integrated light amount is in the range of 0.5 to 6 J / cm ² , preferably 1 to 6 J / cm ^2. it can. If the integrated light amount is less than 0.5 J / cm ² , the liquid adhesive composition may be insufficiently cured, and if it exceeds 6 J / cm ² , the first substrate and the adhesive may be deformed or deteriorated. This is not preferable because of fear.

  Subsequently, the liquid pressure-sensitive adhesive composition 11 is leveled by discharging the liquid pressure-sensitive adhesive composition 11 from the multi-nozzle into a bank portion on the first base material. Subsequently, the first base material and the other second base material selected from the transparent front substrate 12 or the transparent conductive film 13 are bonded together via the bank portion and the liquid adhesive composition 11.

  This bonding may be performed under atmospheric pressure, or may be performed under a reduced pressure of 50 Pa or less in order to prevent bubbles from entering the liquid adhesive composition 11. When performing under reduced pressure, the laminate composed of the first base material, the frame-shaped bank portion, and the liquid adhesive composition 11 discharged into the bank portion is moved under reduced pressure. Under this reduced pressure, The other second base material selected from the transparent front substrate 12 or the transparent conductive film 13 is bonded to the bank portion and the liquid adhesive composition 11.

  After bonding the second substrate, the liquid pressure-sensitive adhesive composition is irradiated with energy rays from above or from the side of the optical member 1 to temporarily cure the liquid pressure-sensitive adhesive composition. Here, only the peripheral edge of the optical member 1 is cured to form the peripheral edge portion 14, and the uncured state is maintained at the center of the optical member 1.

  In the present invention, it is possible to circulate to other processors in the form that has been fixed up to the above steps. According to the present invention, high reworkability can be maintained as long as possible for a long time, and since the transparent front substrate 12 and the transparent conductive film 13 are bonded together at the peripheral edge portion 14, the inside of the peripheral edge portion 14 is liquid. However, the transparent front substrate 12 and the transparent conductive film 13 can be prevented from peeling off.

  In the final processing stage, the uncured liquid pressure-sensitive adhesive composition 11 is irradiated with energy rays from the transparent front substrate 12 side to cure the uncured liquid pressure-sensitive adhesive composition. Further, the liquid pressure-sensitive adhesive composition 11 is cured by moisture and / or heat. Not only curing by irradiation with energy rays but also curing by moisture and / or heat can prevent uncuring of the liquid pressure-sensitive adhesive composition 11 in a region in contact with the printing ink layer 15.

  In addition, also in this manufacturing method, although the case where the combination of a transparent base material and another base material was a combination of the transparent front substrate 12 and the transparent conductive film 13, the said combination is a transparent conductive film and It can also be combined with a liquid crystal substrate.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

<Example 1>
60 parts by mass of energy ray polymerization type urethane acrylate (trade name: T-100, manufactured by KSM) and dicyclopentenyloxyethyl methacrylate (trade name: F-512M, mass average molecular weight (Mw): 262, Hitachi Chemical Co., Ltd. 10.6 parts by mass), 2-hydroxypropyl methacrylate (trade name: HOP, mass average molecular weight (Mw): 130, manufactured by Kyoeisha Chemical Co., Ltd.), 3.5 parts by mass and 2, an ultraviolet polymerization initiator 4,6-trimethylbenzoyl-diphenyl-phosphine-oxide (trade name: TPO, mass average molecular weight (Mw): 348.37, manufactured by BASF) 0.2 parts by mass and 1-hydroxy-cyclohexyl-phenyl-ketone (product) Name: IRGACURE 184, mass average molecular weight (Mw): 204.26, manufactured by BASF) 1.4 24 parts by mass of silicone methoxy oligomer (trade name: KR-213, mass average molecular weight (Mw): about 440, solid content: 100%, viscosity: 18 mPa · s, manufactured by Shin-Etsu Chemical Co., Ltd.) and antioxidant Example 1 1,6-bis (octylthiomethyl) -o-cresol (trade name: IRGASNOX 1520L, mass average molecular weight (Mw): 425, manufactured by BASF) 0.1 parts by mass was dissolved. The liquid adhesive composition which concerns on this was obtained. The color of the liquid pressure-sensitive adhesive composition was transparent.

<Example 2>
Example in the same manner as in Example 1 except that 60 parts by mass of urethane acrylate “T-110” (trade name: T-110, manufactured by KSM Co., Ltd.) was used instead of urethane acrylate “T-100”. 2 liquid adhesive composition was obtained. The color of the liquid pressure-sensitive adhesive composition was transparent.

<Example 3>
Other than using 68 parts by mass of urethane acrylate “T-110” instead of urethane acrylate “T-100”, using 5.4 parts by mass of dicyclopentenyloxyethyl methacrylate, and using 2 parts by mass of 2-hydroxypropyl methacrylate. Obtained the liquid adhesive composition of Example 3 by the method similar to Example 1. FIG. The color of the liquid pressure-sensitive adhesive composition was transparent.

<Example 4>
Example in the same manner as in Example 1 except that 60 parts by mass of urethane acrylate “T-470” (trade name: T-470, manufactured by KSM) was used instead of urethane acrylate “T-100”. 4 liquid adhesive composition was obtained. The color of the liquid pressure-sensitive adhesive composition was transparent.

<Example 5>
Example in the same manner as in Example 1 except that 60 parts by mass of urethane acrylate “T-1000” (trade name: T-1000, manufactured by KSM Co., Ltd.) was used instead of urethane acrylate “T-100”. 5 liquid adhesive composition was obtained. The color of the liquid pressure-sensitive adhesive composition was transparent.

<Comparative Example 1>
Using 12.3 parts by mass of urethane acrylate “T-100”, instead of silicone methoxy oligomer, 24.6 parts by mass of butadiene polymer (trade name: POLYVEST 110, mass average molecular weight (Mw): 2600, manufactured by EVONIK) A comparative example was used in the same manner as in Example 1 except that 5.3 parts by mass of a hydrogenated terpene resin (trade name: Clearon P-85, manufactured by Yasuhara Chemical Co., Ltd.) was newly used as a tackifier. 1 liquid adhesive composition was obtained. Since the liquid pressure-sensitive adhesive composition was white and cloudy, it was confirmed that the liquid pressure-sensitive adhesive composition of Comparative Example 1 was not preferred, without obtaining the optical member of Comparative Example 1.

<Comparative example 2>
Instead of urethane acrylate “T-100”, isoprene resin (trade name: UC203, esterified product of maleic anhydride adduct and 2-hydroxyethyl methacrylate, mass average molecular weight (Mw): 35,000, manufactured by Kuraray Co., Ltd.) 24.6 parts by weight, 10.5 parts by weight of dicyclopentenyloxyethyl methacrylate, 3.5 parts by weight of 2-hydroxypropyl methacrylate, 0,2,4,6-trimethylbenzoyl-diphenyl-phosphine-oxide 2 parts by mass, 1.4 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone, 49.2 parts by mass of butadiene polymer instead of silicone methoxy oligomer, and 4,6-bis (octylthiomethyl) ) -O-cresol is used in an amount of 0.01 parts by mass, Except for the newly using 10.5 parts by weight hydrogenated terpene resin as wearing imparting agent, to obtain a liquid adhesive composition of Comparative Example 2 in the same manner as in Example 1. The color of the liquid pressure-sensitive adhesive composition was transparent.

<Measurement of viscosity>
The viscosity at 25 ° C. of the liquid pressure-sensitive adhesive compositions according to Examples and Comparative Examples was measured. The viscosity was measured using a viscoelasticity measuring device “MCR301” manufactured by Anton Paar. The case where the viscosity is 1000 mPa · s or more and 4000 mPa · s or less is “◯”, and the case where the viscosity is not so is “X”. The results are shown in Table 2.

<Evaluation of residual pressure reduction>
The liquid adhesive compositions according to Examples and Comparative Examples were coated on the entire surface of a 100 × 100 mm glass substrate with a film thickness of 100 μm using an applicator to form a laminate, and the weight W1 before depressurization was measured. Then, this laminated body was pressure-reduced to 50 Pa, and the weight W2 after pressure reduction was measured. And W2 / W1 * 100 was made into the vacuum remaining rate. The case where it was 90% or more and 100% or less was marked with “◯”, and the case where it was not so was marked with “X”. The results are shown in Table 2.

<Evaluation of total light transmittance and haze>
The liquid adhesive composition according to Examples and Comparative Examples was coated on a 100 × 100 mm glass substrate with a film thickness of 100 μm using an applicator, and then the liquid adhesive composition was further irradiated with ultraviolet rays to form a liquid adhesive The agent composition was cured. At this time, the wavelength of ultraviolet rays was 365 nm, and the integrated irradiation doses were 3000, 4000, and 5000 mJ / cm ² .
And the laminated body after hardening was left to stand under high-temperature and high-humidity conditions of temperature 80 ° C. and humidity 90% RH for 3 days. Then, using a haze meter “NDH2000” manufactured by Nippon Denshoku Co., Ltd., the total light transmittance and haze included in the glass substrate before and after being allowed to stand were measured. When the total light transmittance was 85% or more, “◯” was given, and when it was not, “x” was given. The haze was determined to be “◯” when it was 1% or less, and “x” when it was not. The results are shown in Table 2.

<Evaluation of cure shrinkage>
The liquid adhesive composition according to Examples and Comparative Examples was coated on a 100 × 100 mm glass substrate with a film thickness of 100 μm using an applicator, and then the liquid adhesive composition was further irradiated with ultraviolet rays to form a liquid adhesive The agent composition was cured. And the specific gravity of the adhesive composition before and behind hardening was measured. The wavelength of ultraviolet rays was 365 nm, and the integrated irradiation doses were 3000, 4000, and 5000 mJ / cm ² . The specific gravity was measured using an analytical balance “AUX220” manufactured by Shimadzu Corporation.
Evaluation of curing shrinkage is performed by calculating (specific gravity of the pressure-sensitive adhesive composition after curing−specific gravity of the pressure-sensitive adhesive composition before curing) / (specific gravity of the pressure-sensitive adhesive composition after curing) × 100/3. It was. The cure shrinkage rate was “◯” when it was 5% or less, and “x” when it was not. The results are shown in Table 2.

  Liquid adhesive composition containing energy ray polymerization type urethane (meth) acrylate, energy ray polymerization initiator, and silicone oil having a crosslinkable substituent and having a mass average molecular weight (Mw) of 400 to 5,000. Has a viscosity at 25 ° C. of 1000 mPa · s or more and 4000 mPa · s or less, and was confirmed to be excellent in the followability of a step generated between the printing ink layer and the surface of the transparent substrate. Moreover, it was confirmed that both the total light transmittance and haze after being left under high temperature and high humidity were excellent, and there was no problem in quality. Also, since the reduced pressure residual rate and cure shrinkage rate are appropriate, the amount of volatilization of the various components contained in the liquid pressure-sensitive adhesive composition under a reduced pressure state is sufficiently small, and it is possible to handle bonding in a vacuum state. It was confirmed. In addition, since the liquid pressure-sensitive adhesive composition can be supplied in a state of being enclosed in a frame-shaped peripheral portion disposed between the glass substrate and the ITO film, it was confirmed that the reworkability is very excellent ( Examples 1-5).

  On the other hand, when a butadiene polymer is used instead of a silicone oil having a crosslinkable substituent and having a mass average molecular weight (Mw) of 400 to 5000, the liquid pressure-sensitive adhesive composition is white and cloudy, and the quality is poor. It was confirmed that there was a possibility (Comparative Example 1). In addition, when a butadiene polymer is used instead of silicone oil, even if energy ray polymerization type urethane (meth) acrylate is replaced with isoprene resin for quality improvement, the viscosity at 25 ° C. is 4000 mPa · s. Thus, it was confirmed that there is a possibility that moderate step following ability and moderate reworkability may not be provided (Comparative Example 2).

DESCRIPTION OF SYMBOLS 1 Optical member 11 Liquid adhesive composition 12 Transparent front substrate 13 Transparent conductive film 14 Peripheral part

Claims (10)

  Contains an energy ray polymerization type urethane (meth) acrylate, an energy ray polymerization initiator, a silicone oil having a crosslinkable substituent and having a mass average molecular weight (Mw) of 400 to 5000, and a viscosity at 25 ° C. Is a liquid pressure-sensitive adhesive composition having a viscosity of 1000 mPa · s to 4000 mPa · s.   The liquid adhesive composition according to claim 1, wherein the crosslinkable substituent is an alkoxy group.   The liquid adhesive composition according to claim 1 or 2, comprising 10 parts by mass or more and 100 parts by mass or less of the silicone oil with respect to 100 parts by mass of the urethane (meth) acrylate.   The optical member with which the liquid adhesive composition in any one of Claim 1 to 3 is enclosed in the frame-shaped peripheral part arrange | positioned between a transparent base material and another base material.   The optical member according to claim 4, wherein the combination of the transparent substrate and another substrate is a transparent front substrate and a transparent conductive film, or a transparent conductive film and a liquid crystal substrate.   The optical member according to claim 4 or 5 used for a touch panel. A coating step of coating the liquid adhesive composition according to any one of claims 1 to 3 on one first substrate selected from a transparent substrate or another substrate;
A bonding step of bonding the other second substrate selected from the transparent substrate or the other substrate through the liquid adhesive composition;
An energy ray is irradiated from the upper side of the second base material or from the side of the liquid pressure sensitive adhesive composition, and the liquid pressure sensitive adhesive composition applied to the peripheral edge on the first base material is cured and applied to another region. A temporary curing step in which the applied liquid pressure-sensitive adhesive composition is in an uncured temporary curing state; and
The manufacturing method of an optical member provided with.   The method for producing an optical member according to claim 7, wherein the bonding step is performed under reduced pressure.   The method for producing an optical member according to claim 7 or 8, wherein the liquid pressure-sensitive adhesive composition after temporary curing is further irradiated with energy rays from the transparent substrate side to cure the liquid pressure-sensitive adhesive composition.   Furthermore, the manufacturing method of the optical member of Claim 9 which cures the said liquid adhesive composition by moisture and / or a heat | fever.

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