TWI518412B - Light can be applied through the substrate method - Google Patents

Description

Light permeable substrate bonding method

The present invention relates to a method of bonding a light permeable substrate, and more particularly to a method of bonding a light permeable substrate which is cured by using light having a wavelength of more than 380 nm and light having a wavelength of 380 nm or less.

Japanese Patent Publication No. 2013152339 discloses a method of manufacturing a display device comprising the steps of: forming a liquid photocurable resin composition on a light permeable substrate having a light shielding layer, and applying an ultraviolet light to cause the light The curable resin composition is cured to form a cured resin layer, and then a display device is attached to the cured resin layer, and then the ultraviolet light is used to illuminate the display device and the light permeable substrate having the light shielding layer. The resin layer completely cures the hardened resin layer.

However, when UV curing is used at the stage of forming the hardened resin layer, it is difficult to control the degree of curing of the photocurable resin composition, and when the exposure energy is more than 300 mJ/cm ² (UVA cumulative energy), the photocurable resin composition is liable to be formed. Faster curing, so that the hardness of the hardened resin layer is higher, and at the same time, since the photocurable resin composition is cured quickly and the hardness of the cured resin layer is high, it is impossible to flatten the light-permeable substrate of the display device or the light-shielding layer. Flattening the surface so that when the display device is bonded to the light permeable substrate having the light shielding layer, the display device and the light permeable substrate having the light shielding layer are not closely adhered to each other and entrained with bubbles, which in turn causes the hardening The resin layer is liable to have a problem of poor adhesion and a problem that the step caused by the presence of the light shielding layer is not easily filled. Further, when the exposure energy is insufficient, there is a problem that the cured resin layer cannot be shaped.

Chinese Patent Publication No. 102981301 discloses a method of manufacturing a display device comprising the steps of: (1) an adhesive layer forming step of forming an adhesive layer on a selected adhesive forming surface, the selected adhesive forming surface Including the upper surface of the display device and/or the lower surface of the component to be attached; (2) a matching step of aligning the display device and the component to be bonded under illumination of the selected wavelength of the alignment light and Bonding the two, the aligning light is visible light or infrared light, and its wavelength is greater than 400 nm; (3) curing step: curing the adhesive layer with curing light of a selected wavelength to cure the display device And the fixing component is fixed together, the curing light is visible light or long-wave ultraviolet light, the curing light has a wavelength between 315 nm and 760 nm, and the curing light of the selected wavelength and the selected light of the selected wavelength are different respectively. Band. The Chinese patent publication uses long-wavelength ultraviolet light or visible light which has little influence on liquid crystal by curing light, and therefore, when the curing light is used to illuminate the adhesive layer between the display device and the member to be bonded, it can be cured. The alignment effect of the display device and the component to be bonded is effectively ensured, and the aging phenomenon of the liquid crystal is reduced, thereby improving the quality of the display device and prolonging the service life of the display device.

However, in the Chinese patent publication, the adhesive layer is still in a liquid state before the alignment bonding step, so when the alignment bonding step is performed, it is easy to overflow. The situation causes the time-consuming cleaning of the appearance of the display device, and the display device and the component to be attached may cause the display device and the component to be attached to slide due to the fluidity of the adhesive layer, thereby affecting Registration accuracy. Moreover, when the component to be attached is attached to the non-display area of the display device, there is a light-shielding area in the non-display area, which causes light to be easily penetrated, and a device having a side exposure function is required, resulting in the device. The cost increases, and at the same time, because the device with side exposure function is matched with the line light source, there is a problem that the alignment accuracy is not good, and the adhesive layer is not cured well, resulting in an uncured adhesive. Re-infiltration into the cured adhesive layer, causing the cured adhesive layer to be wetted, resulting in uneven thickness of the cured adhesive layer film, which in turn causes the display device to be subjected to an external force The phenomenon of dendritic peeling occurs in the non-display area, and gradually spreads to the display area of the display device.

As apparent from the above description, it is a problem that a person skilled in the art can break through to provide a method of bonding a light permeable substrate which can solve the above problems.

Accordingly, it is an object of the present invention to provide a method of bonding a light permeable substrate which can control a curing rate and form a coating layer having excellent adhesion and softness.

Therefore, the light permeable substrate bonding method of the present invention comprises the following steps: (a) providing a component to be bonded, comprising a display device and a light permeable substrate; (b) applying a curable adhesive composition to at least one of the display device and the light permeable substrate to form a coating layer, wherein the curable adhesive composition comprises a curable oligomer And the photoinitiator component; (c) irradiating the coating layer with light having a wavelength greater than 380 nm to form a semi-cured mucosa; and (d) bonding the display device to the light permeable substrate and using The semi-cured film is irradiated with light having a wavelength of 380 nm or less to form a cured film having a curing ratio of more than 90%, and the display device is bonded to the light-permeable substrate through the cured film.

The effect of the invention is to enable the photoinitiator to be driven at the wavelength by using light curing at a wavelength greater than 380 nm in the stage of forming the semi-cured mucosa, and to effectively control the semi-cured mucosa at high exposure energy. The desired curing rate can be maintained at a certain value to impart good adhesion and softness to the subsequent bonding process. Meanwhile, when the light permeable substrate has a light shielding layer, the semi-cured film can fill a step difference caused by the light shielding layer because of having better softness.

The coating layer has a thickness ranging from 5 μm to 1,000 μm.

In order to make the semi-cured mucous membrane soft to flatten the surface unevenness of the display device or the light permeable substrate, and to make the cured film have better adhesion, the display device and the light permeable substrate are prevented from being attached. In time, the display device and the light permeable substrate are not closely adhered to each other and entrained with bubbles. Preferably, in step (c), the surface curing rate of the semi-cured film ranges from 10% to 80%, and The curing rate of the contact surface of the semi-cured mucus with the member to be bonded ranges from 60% to 90%. The so-called surface cure rate and curing of the contact surface The rate was obtained using an infrared spectrometer equipped with an ATR (Attenuated Total Reflection) fixture and calculated by integrating the integrated area of the peak, and the measurement depth was 0.6 μm to 6 μm.

Since the oxygen has an inhibitory effect on the radical curing, the present invention can adjust the surface curing rate of the semi-cured film in the step (c) by oxygen. Preferably, the curing process is carried out in an environment having oxygen.

<<Display device>>

The display device is, for example but not limited to, a liquid crystal display, a plasma display panel, a 3D stereoscopic display, an organic light-emitting diode (Organic Light-Emitting Diode), and a light-emitting diode display (LED Display). ), or a touch panel (Tough Panel).

<<Light transmissive substrate>>

The light transmissive substrate can be attached to the display area of the display device, to the non-display area, or to internal components in the display device. The light permeable substrate can be, for example, but not limited to, a touch panel, a parallax barrier grating or a lens grating, and a module component including liquid crystal.

Preferably, the light permeable substrate is a light permeable substrate having a light shielding region. The light-permeable substrate having the light-shielding region can be attached to the frame of the display device to shield the internal circuit from the appearance aesthetic effect.

In order to avoid the step difference caused by the light-shielding region of the light-shielding region permeable to the substrate, the display device and the light-permeable substrate having the light-shielding region have voids at the interface of the substrate to generate bubbles. Preferably, the coating layer The thickness is greater than the thickness of the light-shielding region of the substrate through which the light having the light-shielding region is permeable. more Preferably, the thickness of the semi-cured film ranges from 1.1 times to 100 times the thickness of the light-shielding region of the light-permeable substrate having the light-shielding region. The light-shielding region of the light-shielding region having the light-shielding region has a thickness ranging from 0.1 μm to 200 μm.

<<Cureable adhesive composition>>

The curable adhesive composition is applied to at least one of the display device and the light permeable substrate. When the curable adhesive composition is applied to the display device or the light permeable substrate, it may be applied to a flat region of the display device or the light permeable substrate or have a step region. The manner of application is, for example but not limited to, application to a surface on which the coating layer is to be formed or a surface on which the coating layer is to be formed is immersed in the curable adhesive composition.

<curable oligomer>

The curable oligomers are, for example but not limited to, photocurable oligomers or light and heat curable oligomers. Preferably, the photocurable oligomer is selected from a (meth) acrylate oligomer, a polybutadiene oligomer, or a vinyl ester resin (Vinyl Ester Resin). . The (meth) acrylate oligomer is, for example but not limited to, an epoxy (meth) acrylate oligomer or a polyurethane (meth) acrylate. Oligomer, polyester (meth)acrylate oligomer, polyether (meth)acrylate oligomer, or organic germanium (methyl) ) an acrylate-based oligomer or the like. The epoxy (meth) acrylate-based oligomer is, for example, but not limited to, an epoxy polymethacrylic resin or an epoxy polyacrylic resin. The urethane (meth) acrylate oligomer is, for example but not limited to, a grease Adipose urethane acrylate or aromatic urethane acrylate.

<Photoinitiator component>

The photoinitiator component includes a first photoinitiator having an absorption spectrum having a characteristic peak of an absorption wavelength of 340 nm or less and a characteristic peak having an absorption wavelength of more than 340 nm. Preferably, when the first photoinitiator is used in an amount of 0.001 times the total amount of the curable adhesive composition, the absorption area of the first initiator at a wavelength of 310 to 320 nm is 300 parts of the photoinitiator component. The absorption area at a wavelength of up to 400 nm is 0.05 times or more, and the absorption area at a wavelength of 370 to 380 nm is 0.05 times or more of the total absorption area of the photoinitiator component at a wavelength of 300 to 400 nm. The first photoinitiator can be used alone or in combination, and the first photoinitiator for example, but not limited to commercially available product manufactured by Ciba ^{(DAROCUR ® 1173, IRGACURE ® 651} , IRGACURE®907) or IGM Resins Corporation Commercial products (Omnipol 2712, Omnirad 4PBZ, Omnirad 73).

Preferably, the photoinitiator component comprises a second photoinitiator having an absorption spectrum having a characteristic peak having an absorption wavelength of 340 nm or less, and an absorption spectrum having a third photoinitiator having an absorption peak having a wavelength greater than 340 nm.

Preferably, when the second photoinitiator is used in an amount of 0.001 times the total amount of the curable adhesive composition, the absorption area of the second initiator at a wavelength of 310 to 320 nm is the photoinitiator component. 0.1 times or more of the total absorption area at a wavelength of 300 to 400 nm. The second photoinitiator can be used alone or in combination, and the second photoinitiator, for example, but not limited to commercially available product manufactured by Ciba ^{(IRGACURE ® 2959, IRGACURE ® 184} ) or IGM Resins commercially available product manufactured by (Omnipol 100F, Omnipol 910, Omnipol 1001, Omnipol 2702, Omnipol 9220, Omnipol ASA, Omnipol BF, Omnipol PL-2104, Omnipol PL-2300, Omnirad 4HBL, Omnirad 481, Omnirad 500, Omnirad 659).

The third photoinitiator may be used singly or in combination, and the third photoinitiator is, for example but not limited to, a commercially available product of Chitec Co., Ltd. (Chivacure ^® 1256) or a commercial product of Ciba Co., Ltd. (Darocur ^® TPO, IRGACURE ^® 819, IRGACURE ^® 369), etc. Preferably, the absorption spectrum of the third photoinitiator has a characteristic peak having an absorption wavelength of more than 350 nm to less than 400 nm. Preferably, when the third photoinitiator is used in an amount of 0.001 times the total amount of the curable adhesive composition, the absorption area of the third initiator at a wavelength of 380 to 400 nm is the photoinitiator component. 0.1 times or more of the total absorption area at a wavelength of 300 to 400 nm.

Preferably, the weight ratio of the second photoinitiator to the third photoinitiator ranges from 1 to 100.

Preferably, the curable adhesive composition further comprises a solvent.

<solvent>

The solvent is only required to dissolve the components in the curable adhesive composition, and the curable adhesive composition is homogeneous. The solvent may be used singly or in combination, and the solvent is, for example but not limited to, methanol, ethanol, acetone, or toluene or the like. Preferably, the solvent is contained in an amount ranging from 0.01% by weight to 50% by weight based on 100% by weight of the total of the curable adhesive composition.

Preferably, the curable adhesive composition further comprises a curable monomer.

<curable monomer>

The curable monomer may be used singly or in combination, and the curable monomer is, for example, but not limited to, lauryl acrylate or isobornyl acrylate.

Preferably, the curable adhesive composition further comprises a thermal initiator.

<Hot starter>

The hot starter may be used singly or in combination, and the hot starter is, for example but not limited to, a peroxide-based thermal starter or an azo-based hot starter. The peroxide-based thermal initiator may be used singly or in combination, and the peroxide-based thermal initiator is, for example but not limited to, a commercially available product manufactured by AKZO NOBEL (TRIGONOX ^® 187-C30, TRIGONOX 181, PERKADOX ^® IPP). -NS27) and so on. The azo-based thermal initiator may be used singly or in combination, and the azo-based thermal initiator is, for example, but not limited to, a commercially available product (PERKADOX ACCN, PERKADOX AIBN, PERKADOX AMBN-GR) manufactured by AKZO NOBEL.

Preferably, the curable adhesive composition further comprises an additive.

The additive is, for example but not limited to, a plasticizer or a tackifier or the like.

<tackifier>

The tackifier can improve the adhesion of the semi-cured film. When the display device is bonded to the light-permeable substrate, the display device can be closely adhered to the light-permeable substrate without entraining air bubbles. The tackifier may be used alone or in combination, and the tackifier, for example, but not limited to, hydrogenated polybutadiene oligomer, Cray Valley company's commercial product (Wingtack 10, Wingtack EXTRA, Wingtack 86, Ricon ® 131, Ricon ^® 142, Ricon ^® 184), Nippon Soda's commercial products (B series, BI series, GI series, TE series, GQ series, JP series, E series), and Kuraray's commercial products (LIR-50, LIR-310, LIR-390, LIR-410, UC-102, UC-203, LIR-290, LIR-700, LBR-307, LBR-305, LBR-352) and the like. Preferably, the tackifier is present in an amount ranging from more than 0% by weight to less than 60% by weight based on 100% by weight of the total of the curable adhesive composition.

The plasticizer can improve the softness of the semi-cured film. When the display device is bonded to the light-permeable substrate, the display device can be closely adhered to the light-permeable substrate without entraining air bubbles. The plasticizer may be used singly or in combination, and the plasticizer is, for example but not limited to, a commercial product of South Asia Company (DEHP, DIDP, DINP, DBP, DOA, DINA, TOTM, DHIN, DHEH, DOTP) and the like. Preferably, the plasticizer is contained in an amount ranging from more than 0% by weight to 60% by weight based on 100% by weight of the total of the curable adhesive composition.

The invention is further illustrated by the following examples, but it should be understood that this embodiment is intended to be illustrative only and not to be construed as limiting.

<Example 1>

(a) providing a to-be-attached member comprising a display device and a light permeable substrate having a light-shielding region (light-shielding region thickness: 0.1 μm to 50 μm); (b) A curable adhesive composition is applied to the display area of the display device to form a 150 μm coating layer, wherein the curable adhesive composition comprises a curable oligomer (label: DAXIN; model: URX -3100; component: acrylate oligomer), dodecyl acrylate, isobornyl acrylate, GI3000 (label: Nippon-soda; component: hydrogenated polybutadiene oligomer) and photoinitiator (label: Ciba; model: Irgacure 651; composition: 2,2-dimethoxy-2-phenylacetophenone); (c) using a light source (label: Uhao; wavelength: 395 nm) to illuminate the coating layer under normal atmospheric conditions, To form a semi-cured mucosa having a curing rate of 67.11%; (d) bonding the display device to the light-permeable substrate having the light-shielding region, and irradiating with a metal halide lamp (label: Opas; model: XLITE 7250G) The semi-cured film forms a cured film having a curing rate of 94%, and the display device is bonded to the light-permeable substrate having the light-shielding region through the cured film.

<Examples 2 to 7 and Comparative Examples 1 to 2>

Examples 2 to 7 and Comparative Examples 1 to 2 were the same procedures as in Example 1, except that the kinds of photoinitiator and the exposure energy were changed as shown in Table 1. Photoinitiator (label: Ciba; model: Irgacure 184; composition: 1-hydroxycyclohexyphenyl ketone; absorption peaks: 246, 280 and 333 nm). Photoinitiator [label: Ciba; model: Irgacure 819; composition: phenylbis (2,4,6-trimethylbenzoyl) phosphine; absorption peaks: 295 and 370 nm].

<evaluation item>

Curing rate measurement: The curable adhesive compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were respectively applied onto a first slide (2.5 mm x 7.5 mm) and on the first slide. A coating layer having a diameter of 6 mm and a thickness of 0.15 mm was formed. The coating layer was measured using an infrared spectrometer (Perkin-Elmer) equipped with an ATR (Attenuated Total Reflection) fixture, and C=C absorption of 1,600 cm ^-1 to 1,660 cm ^-1 was detected. Peak and CH absorption peak at 2,700 cm ^-1 to 3,100 cm ^-1 . The integrated areas of the C=C absorption peak and the CH absorption peak of the coating layer were A1 and A2, respectively.

Next, the coating layers were irradiated with a light source (label: Uhao; wavelength: 395 nm) under a general atmospheric environment to form a semi-cured mucosa. Irradiation conditions: an exposure amount of 500 mJ/cm ² to 1,500 mJ/cm ² and an exposure intensity of 100 mW/cm ² . The contact surface of the semi-cured mucosa with the first glass slide and the surface of the semi-cured mucosa were measured by the above infrared spectrometer, and the C=C absorption peak of 1,600 cm ^-1 to 1,660 cm ^-1 and 2,700 cm ^- were respectively detected ^. a CH absorption peak of ¹ to 3,100 cm ^-1 , wherein the contact surface of the semi-cured mucosa with the first glass slide is measured by peeling off the semi-cured mucosa from the first glass slide. The integrated areas of the C=C absorption peak and the CH absorption peak of the contact surface of the semi-cured mucosa and the slide glass are C1 and C2, respectively. The integrated areas of the C=C absorption peak and the CH absorption peak on the surface of the semi-cured mucosa are D1 and D2, respectively.

A second slide is attached to the slide with the semi-cured mucosa. Then, the semi-cured film was irradiated with a metal halide lamp (label: Opas; model: XLITE 7250G) to form a cured film. Irradiation conditions: an exposure amount of 500 mJ/cm ² and an exposure intensity of 100 mW/cm ² . Measuring the contact surface of the cured film with the first glass slide and the contact surface of the cured film with the second glass slide using the above infrared spectrometer, and detecting C=C absorption of 1,600 cm ^-1 to 1,660 cm ^-1 , respectively The peak and the CH absorption peak at 2,700 cm ^-1 to 3,100 cm ^-1 , wherein the contact surface of the cured film with the glass slides is measured by peeling the cured film from the slides. The integrated areas of the C=C absorption peak and the CH absorption peak of the contact surface of the cured film and the first glass slide are E1 and E2, respectively. The integrated areas of the C=C absorption peak and the CH absorption peak of the contact surface of the cured film and the second glass slide are F1 and F2, respectively.

X: surface curing rate (%) of semi-cured mucosa = {1 - [(D1 × A2) / (D2 × A1)]} × 100%; Y: curing rate of the contact surface of the semi-cured mucosa and the member to be bonded ( %)={1-[(C1×A2)/(C2×A1)]}×100%; S: curing rate (%) of the contact surface of the cured film and the second glass slide={1-[(F1) ×A2)/(F2×A1)]}×100%; T: curing rate (%) of the contact surface of the cured film and the first glass slide = {1 - [(E1 × A2) / (E2 × A1) ]}×100%.

Curing rate control evaluation:

Excellent: The surface curing rate of the semi-cured film is 60% to 80%, and the curing rate of the contact surface of the semi-cured film and the member to be bonded is 60% to 90%.

The surface cure rate of the semi-cured film is 10% to less than 60%, and the curing rate of the contact surface of the semi-cured film and the member to be bonded is 60% to 90%.

Poor: The surface cure rate of the semi-cured film is less than 10% or more than 80%, and the curing rate of the contact surface of the semi-cured film and the member to be bonded is less than 60% or more than 90%.

Adhesion strength measurement: The curable adhesive compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were respectively applied to a slide glass (2.5 mm x 7.5 mm), and a diameter of 6 mm was formed on the slide glass. A coating layer having a thickness of 0.15 mm was then irradiated with a light source (label: Uhao; wavelength: 395 nm) under a general atmosphere to form a semi-cured mucosa. Irradiation conditions: an exposure amount of 50 mJ/cm ² to 1,500 mJ/cm ² and an exposure intensity of 100 mW/cm ² . Another slide was attached to the slide with the semi-cured mucosa and laminated to a cross. Then, the semi-cured film was irradiated with a metal halide lamp (label: Opas; model: XLITE 7250G) to form a cured film. Irradiation conditions: an exposure amount of 500 mJ/cm ² and an exposure intensity of 100 mW/cm ² . One of the slides was fixed, and another slide was pushed with a Shimadzu tensile tester (model: Shimatsu EZ-Test) at a pushing speed of 5 mm per minute. Finally, the maximum thrust measured by the force gauge is divided by the area of the coating layer to obtain adhesion.

Softness test: The curable adhesive compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were made into dog bone shape samples to be tested in accordance with ASTM D638. Next, the sample to be tested is placed on a jig of a Shimadzu tensile tester (model: Shimatus EZ-Test), and the two ends of the sample to be tested are respectively clamped by a jig, and then the waiting test is pulled at a speed of 50 mm/min. The sample, and until it breaks, gives the Young's modulus.

In summary, by using light curing at a wavelength greater than 380 nm in the stage of forming the semi-cured mucosa, the photoinitiator is driven at the wavelength, and the semi-cured mucosa can be effectively controlled at high exposure energy. The desired curing rate can be maintained at a certain value to impart good adhesion and softness to the subsequent bonding process. At the same time, when the light permeable substrate has a light shielding layer, the softness can fill the step difference caused by the light shielding layer, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (9)

A light permeable substrate bonding method comprising the steps of: (a) providing a component to be bonded, comprising a display device and a light permeable substrate; (b) applying a curable adhesive composition thereto Displaying a device and at least one of the light permeable substrates to form a coating layer, wherein the curable adhesive composition comprises a curable oligomer and a photoinitiator component; (c) using a wavelength Light of more than 380 nm is irradiated to the coating layer to form a semi-cured mucosa; (d) the display device is bonded to the light permeable substrate, and the semi-cured film is irradiated with light having a wavelength of 380 nm or less to form a curing rate. The cured film is in a range of more than 90%, and the display device is bonded to the light permeable substrate through the cured film. The method of bonding a light permeable substrate according to claim 1, wherein the surface curing rate of the semi-cured film ranges from 54.39% to 80%, and the interface between the semi-cured film and the member to be bonded is The cure rate ranges from 60% to 90%. The photo-permeable substrate bonding method according to claim 1, wherein the photoinitiator component comprises a first light having an absorption spectrum having a characteristic peak of an absorption wavelength of 340 nm or less and a characteristic peak having an absorption wavelength of more than 340 nm. Starting agent. The method of bonding a light permeable substrate according to claim 1, wherein the photoinitiator component comprises an absorption spectrum having an absorption wavelength of 340 nm or less. The second photoinitiator of the characteristic peak, and the absorption spectrum has a third photoinitiator having an absorption peak having a wavelength greater than 340 nm. The method of bonding a light permeable substrate according to claim 4, wherein the weight ratio of the second photoinitiator to the third photoinitiator ranges from 1 to 100. The method of bonding a light permeable substrate according to claim 1, wherein the light permeable substrate is a light permeable substrate having a light shielding region. The method of bonding a light permeable substrate according to claim 6, wherein the thickness of the coating layer is greater than the thickness of the light shielding region of the light permeable substrate having the light shielding region. The method of bonding a light permeable substrate according to claim 7, wherein the coating layer has a thickness ranging from 1.1 times to 100 times a thickness of the light shielding region of the light permeable substrate having the light shielding region. The method of bonding a light permeable substrate according to claim 1, wherein the curable adhesive composition further comprises a thermal initiator.