Silicone composition as OCA-like silicone OCR and method for bonding display panel using same

Abstract

The present disclosure provides a silicone composition and a method of bonding a display panel using the same, the silicone composition comprising: (a1) a first organopolysiloxane comprising at least two unsaturated hydrocarbons; (a2) a second organopolysiloxane including at least one unit represented by SiO4 / 2; (b) an organohydrogensiloxane comprising at least two SiH functional groups per molecule and at least one C6 to C20 aryl group per molecule; and (c) a catalyst for a hydrosilylation reaction.

Description

Technical Field

[0001] The present disclosure relates to a silicone composition, specifically, to a silicone composition for bonding (e.g., laminating) a curved panel or multiple panels, more specifically, to a photocurable high-viscosity silicone composition that can be applied to wet bonding and also to gel bonding and solid bonding as an OCA-like silicone OCR, and the present disclosure also relates to a method for bonding a display panel using the silicone composition. Background Art

[0002] A highly transparent silicone adhesive for bonding the display panel and the front surface of the cover causes bonding (eg, lamination) in a liquid state, and thus it can be applied to various designs. Such a silicone adhesive is designed to overcome height differences that may occur in structures.

[0003] As an interlayer bonding material, silicone adhesives have high stability due to the inherent characteristics of flexible structures, such as low shrinkage and stress relief functions, and the excellent properties of silicone itself, such as heat resistance and chemical resistance. Due to such characteristics, silicone adhesives are used as bonding materials in the automotive display field.

[0004] In the field of automotive displays, various types of designs have been popular in recent years, and a multi-panel display type consisting of several layers of panels has become a major trend, and therefore, conventional wet bonding (e.g., liquid bonding) is limited. That is, conventional highly transparent silicone liquid adhesives (e.g., OCR; Optically Clear Resin) have a problem in that they are difficult to adhere after curing. In addition, conventional film-type solid adhesives (e.g., OCA; Optically Clear Resin) have a problem in that it is difficult to solve the step difference problem caused by structural characteristics.

[0005] Therefore, there is a need for an adhesive that can achieve both liquid and solid bonding in the process and solve the step difference problem. Summary of the invention

[0006] Purpose of the Invention

[0007] Embodiments of the present disclosure are directed to a highly transparent photocurable silicone composition applicable to curved designs, capable of implementing wet bonding, gel bonding, and solid bonding in a process of simultaneously bonding multiple panels, and exhibiting stable tack / adhesion by maintaining strong surface tack even after curing.

[0008] Technical means

[0009] The present disclosure provides an organic silicon composition comprising: (a1) a first organic polysiloxane comprising at least two unsaturated hydrocarbons; (a2) at least one organic polysiloxane comprising SiO4 / 2 (b) an organohydrogensiloxane comprising at least two SiH functional groups per molecule and at least one C6 to C 20 an aryl group; and (c) a catalyst for a hydrosilylation reaction.

[0010] Effects of the Invention

[0011] According to one or more embodiments of the present disclosure, the silicone composition can be applied to curved designs, and can implement both wet bonding and solid bonding, and thus can bond multiple panels at the same time. In addition, the silicone composition according to the present disclosure can maintain strong surface tack even after curing, thereby showing stable tack / adhesion to be applicable to bonding of displays and electronic components of various designs.

[0012] The silicone composition according to the present disclosure can also be applied to plastic substrates and thus can be applied to various substrates, and has excellent heat resistance and stress relief properties and thus can be used in automotive display devices or outdoors that are exposed to harsh conditions.

[0013] The silicone composition according to the present disclosure has the advantage that it exhibits a fast curing behavior and bond formation speed, especially at low temperatures, and can therefore be applied in fields where dimensional stability of the module is important in the process, such as curved displays.

[0014] Furthermore, the silicone composition of the present disclosure can adjust viscosity to be applicable to various dispensing methods, and therefore, it is not significantly limited to the dispensing method and can be applied without being greatly affected by the shape of the substrate or the application area. DETAILED DESCRIPTION

[0015] The present disclosure provides an organosilicon composition comprising: (a1) a first organopolysiloxane comprising at least two unsaturated hydrocarbons; (a2) at least one organopolysiloxane comprising SiO 4 / 2 (b) an organohydrogensiloxane comprising at least two SiH functional groups per molecule and at least one C6 to C 20 an aryl group; and (c) a catalyst for a hydrosilylation reaction.

[0016] Each component is described in detail below.

[0017] 1. Component (a)

[0018] Component (a) is an organopolysiloxane. The organosilicon composition according to an embodiment of the present disclosure includes, as component (a), two or more organopolysiloxanes, including (a1) a first organopolysiloxane including at least two unsaturated hydrocarbons; and (a2) including at least one organopolysiloxane composed of SiO 4 / 2The second organopolysiloxane of the unit represented by.

[0019] The first organopolysiloxane (a1) and the second organopolysiloxane (a2) may each independently have a linear structure, a branched structure, a cyclic structure, or a linear structure having a partial branched structure or a partial cyclic structure.

[0020] The first organopolysiloxane (a1) and the second organopolysiloxane (a2) may each independently include C2 to C 20 Alkenyl, and preferably C2 to C 12 Alkenyl groups such as ethenyl, propenyl, isopropenyl, butenyl, hexenyl and octenyl.

[0021] It is preferred that the unsaturated hydrocarbon of the first organopolysiloxane (a1) is an alkenyl group.

[0022] Furthermore, it is preferred that the second organopolysiloxane (a2) includes an unsaturated hydrocarbon.

[0023] Preferably, the first organopolysiloxane (a1) and / or the second organopolysiloxane (a2) comprises C2 to C4 groups bonded to at least one Si at both ends or in the chain. 20 Alkenyl.

[0024] In addition to the alkenyl group bonded to the silicon (Si) atom, the first and second organopolysiloxanes each include an organic group bonded to the silicon atom. As used herein, the organic group is a monovalent hydrocarbon group having 1 to 20 carbon atoms, specifically 1 to 10 carbon atoms, and more specifically 1 to 8 carbon atoms, and may be substituted or unsubstituted. For example, the organic group may be C1 to C 20 Alkyl, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, octyl, nonyl and decyl; C6 to C 20 Aryl, such as phenyl, tolyl, xylyl and naphthyl; and C7 to C 20 Aralkyl groups such as phenethyl and phenpropyl.

[0025] Preferably, the first organopolysiloxane (a1) and / or the second organopolysiloxane (a2) comprises a 1 / 2 、R2SiO 2 / 2 、RSiO 3 / 2 and SiO 4 / 2 at least one unit in .

[0026] Preferably, the first organopolysiloxane (a1) and the second organopolysiloxane (a2) each have a weight average molecular weight ranging from 1,000 to 200,000 g / mol, and more preferably from 10,000 to 50,000 g / mol. Also preferably, they have a viscosity ranging from about 100 to 600,000 mPa·s at 25°C.

[0027] In the silicone composition of the present disclosure, the sum of the contents of the first and second organopolysiloxanes is preferably in the range of 10 to 90 weight % (wt %), more preferably in the range of 50 to 80 wt %, relative to the total amount of the silicone composition.

[0028] 2. Component (b)

[0029] Component (b) is an organohydrogensiloxane comprising at least two SiH functional groups per molecule and at least one C6 to C 20 The aromatic group is a crosslinking agent that reacts with the alkenyl group of component (a) to form a polymer matrix having a network structure.

[0030] It is preferred that component (b) includes hydrogen bonded to a silicon atom in a side chain of the polymer chain (eg, Si-H group).It is also preferred that the organohydrogensiloxane of component (b) includes Si-H functional groups at both ends.

[0031] Preferably component (b) comprises at least one phenyl group per molecule.

[0032] Component (b) may have a general formula of R3SiO 1 / 2 、R2SiO 2 / 2 、RSiO 3 / 2 and SiO 4 / 2 The organosiloxane structure formed by the units represented by has a linear structure, a branched structure, a cyclic structure, or a linear structure having a partial branched structure or a partial cyclic structure.

[0033] Specifically, component (b) may include C1 to C 20 The monovalent hydrocarbon group as the organic group may include, more specifically, a group selected from C1 to C 20 Alkyl and C7 to C 20 The hydrocarbon group of aralkyl.

[0034] In the organosilicon composition of the present disclosure, in the SiO 4 / 2 In the case of an organohydrogensiloxane formed by a unit represented by 3 Up to 10 4 Pa, the content of the organohydrogensiloxane of component (b) is preferably in the range of about 1 to 50 wt %, and more preferably in the range of about 10 to 20 wt %, relative to the total amount of the silicone composition.

[0035] In the organosilicon composition of the present disclosure, in order to rapidly cure at low temperatures after UV irradiation, it is preferred that the content of the organohydrogensiloxane of component (b) is such that the silicon-bonded hydrogen atoms in component (b) are 0.5 mol or more, and more preferably in the range of 0.6 to 0.9 mol, per 1 mol of the alkenyl groups of components (a1) and (a2).

[0036] In the silicone composition of the present disclosure, in order to maintain a damping factor of 0.5 or more and a damping factor of 10 3 Up to 10 4 The modulus of Pa, in the case of an organosiloxane having a long molecular length by having SiH at both ends, it is preferred that the content of the organohydrogensiloxane of component (b) is such that the hydrogen atoms bonded to silicon in component (b) is 0.3 mol or more, and more preferably in the range of 0.5 to 0.8 mol, relative to 1 mol of the alkenyl groups of components (a1) and (a2).

[0037] 3. Component (c)

[0038] Component (c) is a catalyst for hydrosilylation reaction. The catalyst is a component for promoting the reaction between the above-mentioned organopolysiloxane (a) and the organohydrogensiloxane (b). Preferably, the catalyst is a metal catalyst that can be oxidized by UV, and the applicable catalyst in the present disclosure is not particularly limited, as long as it is used in the hydrosilylation reaction of this area, such as platinum-based catalysts, palladium-based catalysts or rhodium-based catalysts, wherein preferably there is platinum or platinum compounds with excellent reactivity. For example, there are platinum clusters, platinum black, platinum chloride, chloroplatinic acid and its salt, alcohol-modified chloroplatinic acid, chloroplatinic acid-olefin complex, platinum coordination compounds, etc., each of which is loaded on a carrier such as silicon dioxide or carbon.

[0039] In the organosilicon composition of the present disclosure, the content of the catalyst of component (c) is not particularly limited, but if the content of the catalyst is too low, the effect as a catalyst may not be obtained, and on the other hand, if the content of the catalyst is too high, the optical stability after sufficient curing may be reduced, so it is not economical. In addition, since the catalyst content affects the curing behavior, in order to achieve low-temperature rapid curing, the catalyst content of component (c) is preferably adjusted to a range of about 10 to 100 ppm according to the metal content, specifically, a range of about 15 to 30 ppm.

[0040] 4. Others

[0041] In addition to the above components (a) to (c), the organosilicon composition according to the present disclosure may optionally include additives commonly used in the art, depending on the purpose and use environment of the composition, examples of which may include but are not limited to binders, coupling agents, dyes, pigments, flame retardants, thickeners, leveling agents, thixotropic agents, etc.

[0042] The content of the additive is not particularly limited and can be used within a conventional range known in the art. For example, the content of the additive can be in the range of about 0.001 to 10 wt %, specifically in the range of about 0.01 to 5 wt %, and more specifically in the range of about 0.1 to 3 wt %, relative to the total amount of the silicone composition.

[0043] The viscosity of the silicone composition according to the present disclosure at 25° C. is preferably in the range of 100 to 100,000 mPa·s relative to the kinematic viscosity in the range of 10 to 25 rpm, so as to be applied to various dispensing equipment. Specifically, it is more preferred that the viscosity is in the range of 100 to 5,000 mPa·s for nozzle dispensing, in the range of 5,000 to 20,000 mPa·s for slit coating, in the range of 5,000 to 20,000 mPa·s for screen printing, and in the range of 20,000 to 100,000 mPa·s for stencil printing.

[0044] Preferably, the silicone composition according to the present disclosure has a damping factor of 0.5 or greater after being fully cured. 3 Up to 10 4 Modulus in the Pa range.

[0045] The silicone composition according to the present disclosure preferably has a surface tack of at least 20 g.sec or greater under the following conditions: 5 mm cylindrical stainless steel probe, 100 g load, 5 second contact time, and 0.5 mm / s test speed after full cure, and preferably has a tack of at least 100 gf / cm or greater relative to the 180° peel strength (Glass / PET), even in the case of bonding after full cure.

[0046] Furthermore, for effective leveling after application, it is preferred that the thixotropic index becomes closer to 1 with respect to a similar dynamic viscosity in the range of 0.1 to 25 rpm.

[0047] The UV curing conditions of the silicone composition of the present disclosure are not particularly limited, but should be adjusted according to the time period from UV irradiation to bonding in the corresponding process. For example, for wet bonding, it can be 1,000 to 5,000 mJ / cm 2 The range of the present invention is as follows, and a post-curing process by heating can be added for gel bonding or solid bonding. The post-curing process by heating is not particularly limited, and it can be, for example, a heating block, infrared (IR) irradiation, a heating chamber, and a heating curtain.

[0048] The silicone composition according to the present disclosure can be applied to all bondings of bonding immediately after UV irradiation, bonding after gelation, and bonding after sufficient curing. That is, by using the silicone composition according to the present disclosure, wet bonding and solid bonding can be performed simultaneously to bond multiple display panels at one time. The silicone composition according to the present disclosure can be used for bonding, sealing or assembly in display devices, electronic components, solar cell modules, semiconductors or automotive parts. For example, in the case of a display device, it can be used as a housing or backlight unit in a liquid crystal display (LCD), a light emitting diode (LED) display or an organic electroluminescent (EL) display.

[0049] Hereinafter, the present disclosure will be described in detail through embodiments. However, the following embodiments only illustrate the present disclosure, and the present disclosure is not limited to the following embodiments.

[0050] [Embodiments 1 to 9, Comparative Examples 1 to 3]

[0051] The following components were uniformly mixed in vacuum at the composition ratio (parts by mass) shown in Table 1 to prepare light-curable, high-viscosity, fast-curing silicone compositions of the embodiment (Embod.) and the comparative example (Comp.Ex.). In each structural formula, Me is a methyl group and Vi is a vinyl group.

[0052] [Table 1]

[0053]

[0054] The following components are used for component (a).

[0055] a-1: (CH2=CHMe2SiO(SiMe2O)xSiMe2CH=CH2), Mw=7800g / mol, flat

[0056] Average chain length = 110

[0057] a-2: (CH2=CHMe2SiO(SiMe2O)xSiMe2CH=CH2), Mw=36800g / mol,

[0058] Average chain length = 441

[0059] a-3: (CH2=CHMe2SiO(SiMe2O)xSiMe2CH=CH2), Mw=76500g / mol,

[0060] Average chain length = 1040

[0061] a-4:M5M Vi 1Q4

[0062] a-5:M7MVi 1Q 12

[0063] The following components are used for component (b).

[0064] b-1: H-(SiMe2O)xSiMe2-H, Mw=5,000g / mol

[0065] b-2: H-(SiMe2O)xSiMe2-H, Mw=16,400g / mol

[0066] b-3: Me3SiO(Me2SiO)x(MeHSiO)ySiMe3, Mw=5,000g / mol

[0067] b-4: MD Ph 40 -DH 20 -M

[0068] b-5: H-M2-D Ph 2-M2-H

[0069] The following components are used for component (c).

[0070] c-1: Methylcyclopentadienyl-trimethyl-platinum(IV)

[0071] [Experimental Example]

[0072] The compositions of Embodiments 1 to 5 and Comparative Examples 1 to 3 were measured for viscosity, modulus, surface tack, peel strength, etc. The results are shown in Table 2 below.

[0073] [Table 2]

[0074]

[0075] Viscosity was measured using a rheometer (Anton Paar, CP50-2, 25 / shear rate) and hardness was measured using a 9.38 g penetration cone.

[0076] The 180° peel strength was measured by coating the silicone composition with a thickness of 0.3 mm on a glass substrate (width 50 mm x length 100 mm x thickness 5 mm) which was subjected to a 2500 mW / cm 2 365nm LED light at 3,000mJ / cm 2 Irradiation.

[0077] In the case of (1), the PET film was bonded within 1 minute, in the case of (2), the PET film was bonded after confirming the gel state at a time point in the range of 3 to 5 minutes, and in the case of (3), it was left at room temperature for one day to fully cure, and then the PET film was bonded.

[0078] According to ASTM D 3330, the sample is moved in a 180° direction, the PET film is peeled at a rate of 300 mm / min, and the 180° peel strength (gf / cm) of the silicone composition is measured from the maximum stress obtained. In this case, if the fracture mode (e.g., failure mode) remains on both substrates, it is determined as "cohesive", and if it remains on only one substrate, it is determined as "adhesive".

[0079] The modulus was measured using a rheometer (Anton Paar, PP12.5, 1 Hz) under shear stress after full curing.

[0080] The damping factor is a value obtained by dividing the loss modulus (G") by the storage modulus (G') obtained in the modulus measurement.

[0081] Surface tack was estimated by measuring the tack, which was evaluated against the conditions of a 5 mm cylindrical stainless steel probe, 100 g load, 5 s contact time and 0.5 mm / s test speed.

[0082] In the case of Embodiments 1 to 3, all compositions were cured (no uncured portion) and generally showed a cohesive fracture mode, indicating that these compositions can be used not only for wet bonding but also for gel and solid bonding. In the case of Embodiments 4 and 5, the bonding mode was observed under the bonding condition after sufficient curing, and therefore, it is understood that they can only be applied to gel bonding.

[0083] In the case of Comparative Examples 1 to 3, the compositions lacking part of components (a) and (b) showed adhesive failure modes in both gel bonding and bonding after sufficient curing, and it is understood that they are not applicable to gel bonding and solid bonding.

Claims

1. An organosilicon composition comprising: (a1) a first organopolysiloxane comprising at least two unsaturated hydrocarbons; (a2) comprising at least one SiO 4 / 2 A second organopolysiloxane of units represented by; (b) an organohydrogensiloxane comprising at least two SiH functional groups per molecule and at least one C6 to C 20 aryl; and (c) Catalysts for hydrosilylation reactions. 2 . The organosilicon composition according to claim 1 , wherein the unsaturated hydrocarbon of component (a1) is an alkenyl group. 3 . The silicone composition according to claim 1 , wherein component (a2) comprises an unsaturated hydrocarbon.

4. The organic silicon composition according to claim 1, wherein component (a1) and / or component (a2) comprises C2 to C4 bonded to at least one Si at both ends or in the chain. 20 Alkenyl.

5. The organosilicon composition according to claim 1, wherein component (a1) and / or component (a2) comprises R3SiO 1 / 2 、R2SiO 2 / 2 、RSiO 3 / 2 and SiO 4 / 2 One or more units. 6 . The silicone composition according to claim 1 , wherein the weight average molecular weight of component (a1) and / or component (a2) is in the range of 1,000 to 200,000 g / mol.

7. The organosilicon composition according to claim 1, wherein component (b) comprises at least one phenyl group per molecule.

8. The organosilicon composition according to claim 1, wherein The amount of hydrogen atoms bonded to silicon of the component (b) is 0.3 mol or more relative to 1 mol of the alkenyl groups of the component (a1) and / or the component (a2). 9 . The organosilicon composition according to claim 1 , wherein the organohydrogensiloxane of component (b) comprises Si—H functional groups at both ends.

10. The organosilicon composition according to claim 1, wherein component (c) is a UV-oxidizable metal catalyst.

11. The silicone composition according to claim 1, wherein component (c) comprises 10 to 100 ppm of the metal relative to the total weight of the silicone composition. 12 . The silicone composition according to claim 1 , having a viscosity in the range of 100 to 100,000 mPa·s at 25° C. relative to a kinematic viscosity in the range of 10 to 25 rpm.

13. The silicone composition of claim 1, which has a damping factor of 0.5 or more after being fully cured.

14. The organosilicon composition according to claim 1, which has a 3 Up to 10 4 Modulus in the Pa range.

15. The silicone composition of claim 1, having a surface tack of at least 20 g.sec or greater under the conditions of a 5 mm cylindrical stainless steel probe, a 100 g load, a 5 second contact time, and a 0.5 mm / s test speed after full cure.

16. The silicone composition according to claim 1, having a tack of at least 100 gf / cm or more relative to 180° peel strength (glass / PET) even in the case of bonding after being fully cured.

17. The organosilicon composition according to claim 1, which can be applied to all wet bonding as well as gel bonding and solid bonding as an OCA-like organosilicon OCR.

18. The organosilicon composition according to claim 1, which can be used for bonding, sealing or assembling display devices, electronic components, solar cell modules, semiconductors or automobile components.

19. The organosilicon composition according to claim 1, used for bonding a curved panel or a plurality of panels.

20. A method for simultaneously bonding display panels, the method comprising: The silicone composition of claim 1 is used to simultaneously perform wet bonding, gel bonding and solid bonding, and the gel bonding and solid bonding can follow the following process: first, UV (280-380 nm) activation; then, optionally, post-curing with heating (heating block, oven, heating curtain, IR, etc.); optionally, laminating with another part in the gel state of the silicone, and then autoclaving at 25°C-60°C and 3-12 kgf.

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