Photocurable silicone composition

Abstract

The present invention relates to a photocurable silicone composition comprising (A) 8 to 24 wt% of a thiol-based compound containing two or more thiol groups; (B) 5 to 20 wt% of a siloxane compound containing three or more C2-C12 alkenyl groups, and a C6-C12 aryl group; (C) 15 to 79 wt% of an organopolysiloxane containing vinylsiloxy groups at both ends, represented by Formula 1; and (D) 0.01 to 5 wt% of a photoinitiator; based on the total weight of the photocurable silicone composition, wherein the ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition is 0.5 to 2.

Description

PHOTOCURABLE SILICONE COMPOSITION

[0001] The present disclosure relates to a photocurable silicone composition, a cured body obtained by curing the same, and an article comprising the cured body of the same.

[0002] Ultraviolet (UV) curable materials are used in many display applications due to their freedom to use temperature-sensitive substrates and cost-effective operational processing.

[0003] Meanwhile, in the display market, display sizes are becoming both wider and bigger by reducing the bezel area. In order to meet this trend, changes in display device structure are necessary, and furthermore, a photocurable silicone composition with excellent processability and reliability is needed.

[0004] In particular, the ultraviolet curable silicone composition must have a viscosity low enough to fill narrow gaps through a jet or other dispensing process, and must be able to be stably deep cured via ultraviolet energy. Additionally, there should be no migration or bleed-out phenomenon so that the composition does not flow out and cause problems in the device.

[0005] A typical ultraviolet curing silicone composition requires more than 1,000 mJ / cm2of ultraviolet energy for a complete radical curing reaction, and secondary curing such as heat curing or condensation curing is generally required for complete and stable deep curing. However, some device designs have narrow and deep gaps, and do not expose the material to sufficient amounts of UV energy. In this case, reliability may be reduced due to insufficient curing and oil bleeding. Accordingly, in order to overcome the limitations of the application field and realize articles with stable curing and excellent performance, a photocurable silicone composition that is highly reactive at low ultraviolet energy, specifically at ultraviolet energy of less than 1,000 mJ / cm2, is required.

[0006] The objective of the present disclosure is to provide a photocurable silicone composition that prevents oil bleed-out after ultraviolet curing, can sufficiently fill even narrow gaps, and enables fast and stable deep curing even at low ultraviolet energy.

[0007] According to one embodiment of the present disclosure, there is provided a photocurable silicone composition comprising:

[0008] (A) 8 to 24 wt% of a thiol-based compound containing two or more thiol groups;

[0009] (B) 5 to 20 wt% of a siloxane compound containing three or more C2-C12alkenyl groups, and a C6-C12aryl group;

[0010] (C) 15 to 79 wt% of an organopolysiloxane containing vinylsiloxy groups at both ends, represented by Formula 1 below; and

[0011] (D) 0.01 to 5 wt% of a photoinitiator;

[0012] based on the total weight of the photocurable silicone composition,

[0013] wherein the ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition is 0.5 to 2.

[0014] [Formula 1]

[0015]

[0016] wherein, R1represents a substituted or unsubstituted C1-C12alkyl group,

[0017] R2represents a C6-C12aryl group,

[0018] R3to R6each independently, represent a substituted or unsubstituted C1-C12alkyl group, and

[0019] n is an integer of 1 to 30.

[0020] According to another embodiment of the present disclosure, there is provided a cured body obtained by curing the photocurable silicone composition.

[0021] According to another embodiment of the present disclosure, there is provided an article comprising the cured body.

[0022] By using the photocurable silicone composition of the present disclosure, the bleed-out phenomenon after curing by ultraviolet irradiation can be eliminated, and even narrow gaps can be easily filled due to the low viscosity of the composition after curing; it also has excellent reactivity even at low ultraviolet energy, so that stable and fast deep curing can be achieved. Accordingly, articles with excellent performance and reliability can be implemented.

[0023] Fig. 1 shows the results of measuring the bleed-out rate of the photocurable silicone compositions according to Example 1 and Comparative Example 9.

[0024] Hereinafter, the photocurable silicone composition according to the present disclosure will be described in detail so that it can be easily practiced by those skilled in the art.

[0025] According to one embodiment of the present disclosure, there is provided a photocurable silicone composition comprising: (A) 8 to 24 wt% of a thiol-based compound containing two or more thiol groups; (B) 5 to 20 wt% of a siloxane compound containing three or more C2-C12alkenyl groups, and a C6-C12aryl group; (C) 15 to 79 wt% of an organopolysiloxane containing vinylsiloxy groups at both ends, represented by Formula 1 below; and (D) 0.01 to 5 wt% of a photoinitiator; based on the total weight of the photocurable silicone composition, wherein the ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition is 0.5 to 2.

[0026] [Formula 1]

[0027]

[0028] wherein, R1represents a substituted or unsubstituted C1-C12alkyl group,

[0029] R2represents a C6-C12aryl group,

[0030] R3to R6each independently, represent a substituted or unsubstituted C1-C12 alkyl group, and

[0031] n is an integer of 1 to 30.

[0032] The thiol-based compound containing two or more thiol groups (A) may be represented by the following formula:

[0033] HS-(CH2CH2)a-(OCH2CH2)b-(CH2CH2)c-SH

[0034] wherein, a and c each independently, represent an integer of 0 to 10, and b is an integer of 1 to 10.

[0035] The thiol-based compound containing two or more thiol groups (A) enables fast, deep curing and has excellent compatibility with a polysiloxane compound, preferably a phenyl-based polysiloxane compound.

[0036] In addition, the thiol-based compound containing two or more thiol groups (A) acts as a crosslinking agent when the composition is cured, and upon exposure to ultraviolet (UV) and / or visible light, the thiol group may react with a carbon-carbon unsaturated bond and may be added across it. Specifically, the thiol group contained in the thiol-based compound (A) may participate in a thiol-ene reaction with the unsaturated alkenyl group of the siloxane compound contained in the photocurable silicone composition or with the terminal unsaturated alkenyl group on the organopolysiloxane.

[0037] The thiol-based compound (A) may contain two or more thiol groups, for example, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more thiol groups. The number of the thiol groups is an average value for all molecules of the thiol-based compound. Preferably, the number of the thiol groups per molecule of the thiol-based compound can be determined from knowledge of the structures of the components used to prepare the composition. If it is not known which material is used to prepare the composition, nuclear magnetic resonance (NMR) spectroscopy and elemental analysis can be used to determine the number of the thiol groups per molecule for the thiol-based compound.

[0038] The thiol-based compound (A) may comprise at least one selected from the group consisting of 2,2′-(ethylenedioxy)diethanethiol, ethylene glycol bis-mercaptoacetate, 1,6-hexanedithiol, 2,5-hexanedithiol, benzene-1,4-dithiol, 1,3-propanedithiol, 1,2-ethanedithiol, trimethylolpropane tris(3-mercaptopropionate) (TMPTMP), pentaerythritol tetrakis (3-mercaptopropionate (PETTMP), tetra(ethylene glycol)dithiol, hexa(ethylene glycol)dithiol, 2,2'-thiodiethanethiol, 1,4-butanedithiol and mixtures thereof.

[0039] The photocurable silicone composition may comprise the thiol-based compound (A) in an amount of 8 to 24 wt%, preferably 10 to 20 wt%, and more preferably 10 to 17 wt%, based on the total weight of the composition. When the content of the thiol-based compound satisfies the above numerical range, the bleed-out phenomenon that may occur during the curing process is suppressed and the viscosity of the photocurable silicone composition containing the thiol-based compound is maintained low to enable deep curing.

[0040] The siloxane compound (B) may contain three or more C2-C12alkenyl groups and a C6-C12aryl group, and preferably contains three or more C2-C6alkenyl groups, and a phenyl group.

[0041] The alkenyl group may specifically be a vinyl group, an allyl group, a methacryloyl group, an acryloyl group, a styrenyl group, or a norbornenyl group, preferably a vinyl group.

[0042] Specifically, the siloxane compound (B) may be represented by the following Formula 2.

[0043] [Formula 2]

[0044]

[0045] wherein, R7to R12each independently, represent a substituted or unsubstituted C1-C12alkyl group, preferably a substituted or unsubstituted C1-C6alkyl group, and more preferably an unsubstituted C1-C3alkyl group.

[0046] The siloxane compound (B) may enable rapid deep curing. In particular, the photocurable silicone composition according to the present disclosure may enable deep curing to a depth of 20 mm or more, preferably 22 mm or more, and more preferably 25 mm or more, by simultaneously comprising the siloxane compound (B) together with the thiol-based compound (A). In addition, the siloxane compound (B) together with the thiol-based compound (A) may enable an improvement in curing speed, and may enable a curing reaction at low energy, 500 mJ / cm2or less, preferably 450 mJ / cm2or less, and more preferably 350 mJ / cm2or less.

[0047] The photocurable silicone composition may comprise the siloxane compound (B) in an amount of 5 to 20 wt%, preferably 6 to 18 wt%, and more preferably 10 to 15 wt%, based on the total weight of the composition. When the content of the siloxane compound (B) satisfies the above numerical range, the bleed-out phenomenon that may occur during the curing process is suppressed, the curing reaction can be accelerated and the curing speed can be improved. In addition, the viscosity of the photocurable silicone composition comprising the siloxane compound (B) is maintained low to enable deep curing.

[0048] The organopolysiloxane (C) may be represented by Formula 1 above. In Formula 1, R1represents a substituted or unsubstituted C1-C12alkyl group, R2represents a C6-C12aryl group, R3to R6each independently, represent a substituted or unsubstituted C1-C12alkyl group, and n represents an integer of 1 to 30. Preferably, R1represents a substituted or unsubstituted C1-C6alkyl group, R2represents a C6-C12aryl group, R3to R6each independently, represent an unsubstituted C1-C6alkyl group, and n represents an integer of 20 to 30. More preferably, R1represents an unsubstituted C1-C3alkyl group, R2represents an unsubstituted phenyl group, R3to R6each independently, represent an unsubstituted C1-C3alkyl group, and n represents an integer of 22 to 27.

[0049] Meanwhile, R3to R6in Formula 1 may be identical to or different from each other.

[0050] The organopolysiloxane (C) may be crosslinked by participating in a thiol-ene reaction with the thiol-based compound (A). Crosslinking through this thiol-ene reaction may prevent bleed-out phenomenon that occurs after photocuring.

[0051] The organopolysiloxane (C) contains a C6-C12aryl group, and the presence of the aryl group may serve to increase compatibility in the photocurable silicone composition along with the thiol-based compound (A). In order to achieve suitable compatibility between the thiol-based compound (A) and the organopolysiloxane (C), the organopolysiloxane (C) may contain a C6-C12aryl group in an amount of 30 mol% or more, preferably 50 mol% or more, more preferably 70 mol% or more, and most preferably 80 mol% or more relative to the silicon atoms in component (C).

[0052] In particular, the free radical polymerization reaction of organopolysiloxane (C) is inhibited by oxygen, and as the composition is exposed to more oxygen during the photocuring reaction, a serious bleed-out phenomenon may occur after photocuring. For example, a photocurable silicone composition based on methyl polysiloxane with high gas permeability is exposed to more oxygen during the photocuring reaction, so bleed-out easily occurs. However, the photocurable silicone composition according to the present disclosure minimizes the amount of oxygen contact during the photocuring reaction by comprising a C6-C12aryl group with low gas permeability in the organopolysiloxane (C), thereby suppressing the bleed-out phenomenon after photocuring.

[0053] The photocurable silicone composition may comprise the organopolysiloxane (C) in an amount of 40 to 79 wt% based on the total weight of the composition. When the content of the organopolysiloxane (C) satisfies the above numerical range, not only can bleed-out phenonmenon after curing be prevented, but it also enables the implementation of a low-viscosity photocurable silicone composition and deep curing, and the curing speed can be improved.

[0054] The photoinitiator serves to generate free radicals when exposed to light. The photoinitiator may be an ultraviolet light photoinitiator, a visible light photoinitiator, or a combination thereof, and preferably an ultraviolet light photoinitiator.

[0055] Ultraviolet light photoinitiators can generate free radicals when exposed to ultraviolet light. The ultraviolet light photoinitiator may comprise at least one compound selected from the group consisting of biimidazole photoinitiator, oxime ester photoinitiator, a substituted or unsubstituted phosphinate, a substituted or unsubstituted benzophenone, a substituted or unsubstituted acetophenone, a benzoin and an alkyl ester thereof, a substituted or unsubstituted xanthone, and combinations thereof. For example, 2,2'-bis(o-chlorophenyl)-4,4'-5,5'-tetraphenyl-1,2'-biimidazole, 1-(6-o-methylbenzoyl-9-ethylcarbazol-3-yl)-(3-cyclohexylacetone)-1-oximester, ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, ethyl-2,4,6-trimethylbenzoylphenyl phosphinate, bis(2,4,6-trimethyl benzoyl)-phenylphosphine oxide, diethoxyacetophenone (DEAP), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, diethoxyxanthone, chloro-thioxanthone, azo-bisisobutyronitrile, N-methyl diethanolaminebenzophenone, 2-hydroxy-2-methylpropiophenone, or combinations thereof may be used as the ultraviolet light photoinitiator.

[0056] Visible light photoinitiators can generate free radicals when exposed to visible light (wavelengths ranging from 390 to 700 nm). The visible light photoinitiator may comprise at least one compound selected from the group consisting of camphorquinone peroxyester initiator, non-fluorene carboxylic acid peroxyester initiator, alkyl thioxanthone such as isopropyl thioxanthone, and combinations thereof.

[0057] Preferably, the photoinitiator may comprise a phosphorus atom, and specifically, the photoinitiator may comprise ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide or (2,4,6-trimethylbenzoyl)diphenylphosphin oxide.

[0058] The photoinitiator may absorb a wavelength of 200 to 450 nm, preferably 300 to 430 nm, and more preferably 350 to 410 nm. In this way, the photoinitiator absorbs long-wavelength ultraviolet rays, which are very useful for deep curing, so that even a narrow deep gap can be completely cured by using a photocurable silicone composition comprising the photoinitiator, and thereby bleed-out phenomenon can be suppressed and reliable curing can be performed.

[0059] The photocurable silicone composition may comprise the photoinitiator (D) in an amount of 0.01 to 5 wt%, preferably 0.1 to 3 wt%, and more preferably 0.2 to 2 wt% based on the total weight of the composition. When the content of the photoinitiator (D) satisfies the above numerical range, not only can curing proceed efficiently, but also a cured body with light resistance can be formed.

[0060] The ratio of thiol groups to alkenyl groups (SH / Vi ratio) in the photocurable silicone composition may be 0.5 to 2, preferably 0.7 to 1.7, and more preferably 0.9 to 1.5. Here, the amount of alkenyl groups can be calculated based on the vinyl groups. If the SH / Vi ratio in the composition exceeds the upper limit of the above numerical range, the cured material may turn yellow and deep curing may become impossible, and if it falls below the lower limit of the above numerical range, physical properties such as modulus and hardness of the cured silicone composition may become inferior.

[0061] The photocurable silicone composition may further comprise a phenolic-based compound substituted with a straight chain or branched chain C1-C6alkyl group, or an unsubstituted polyphenol-based compound. For example, the photocurable silicone composition may further comprise butylated hydroxytoluene (BHT) or 1,2,3-trihydroxybenzene. The photocurable silicone composition may comprise an additionally comprised compound in an amount of 10 ppm to 400 ppm, preferably 20 ppm to 300 ppm, based on the total weight of the composition.

[0062] Another embodiment of the present disclosure provides a cured body obtained by curing the photocurable silicone composition.

[0063] The cured body is a cured body obtained by irradiating light to the photocurable silicone composition according to the present disclosure. Examples of light used to cure the photocurable silicone composition comprise ultraviolet light and visible light, wherein the light has a wavelength in the range of 200 to 450 nm, preferably 300 to 430 nm, and more preferably 350 to 410 nm. Accordingly, excellent curability can be achieved and the cured body may not be decomposed by light.

[0064] The form of the cured body is not limited and may be in the form of a sheet, film, or block. The cured body can be combined with various substrates.

[0065] Another embodiment of the present disclosure provides an article comprising the cured body. Examples of such articles include adhesives, substrate masking, and sealing agents for flat panel displays, including liquid crystal displays or organic electroluminescent displays.

[0066] Hereinafter, the present disclosure will be described in more detail through examples. However, these examples are only intended to aid understanding of the present disclosure, and the scope of the present disclosure is not limited to these examples in any way.

[0067] Example 1: Preparation of photocurable silicone composition 1

[0068] Firstly, 12.6 parts by mass of 2,2'-(ethylenedioxy)diethanethiol (DODT) and 20 ppm of butylhydroxytoluene (BHT) were added to a 100 ml dental mixer (Thinky, ARV-310), and mixed at 2000 rpm for 60 seconds. Thereafter, a batch of 34.29 parts by mass of (M0.5(Methyl2Vinyl)T0.5(Phenyl)) resin (RMS 310) / 41.91 parts by mass of phenylsiloxane (MVi2DPh25, MP-153) having a vinylsiloxy terminal and 10.5 parts by mass of 3-((dimethyl(vinyl)silyl)oxy)-1,1,5,5-tetramethyl-3-phenyl-1,5-divinyltrisiloxane (RMS 313) were added thereto.

[0069] The mixture was again mixed at 2000 rpm for 60 seconds. Then, 0.7 parts by mass of ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate (Omnirad TPO-L) was added to the mixture and mixed once again at 2000 rpm for 60 seconds.

[0070] The ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition was 1.

[0071] Example 2: Preparation of photocurable silicone composition 2

[0072] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 34.38 parts by mass of RMS 310 resin / 42.02 parts by mass of MP-153 and 0.5 parts by mass of Omnirad TPO-L were used.

[0073] Example 3: Preparation of photocurable silicone composition 3

[0074] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 34.51 parts by mass of RMS 310 resin / 42.19 parts by mass of MP-153 and 0.2 parts by mass of Omnirad TPO-L were used.

[0075] Example 4: Preparation of photocurable silicone composition 4

[0076] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 33.34 parts by mass of RMS 310 resin / 40.76 parts by mass of MP-153 was used, and 6.3 parts by mass of RMS 313 and 6.3 parts by mass of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane (RMS 312) were used instead of 10.5 parts by mass of RMS 313.

[0077] Example 5: Preparation of photocurable silicone composition 5

[0078] A photocurable silicone composition was prepared in the same manner as in Example 1, except 78.2 parts by mass of MP-153 was used instead of a batch of 34.29 parts by mass of RMS 310 resin / 41.91 parts by mass of MP-153, and 10.8 parts by mass of DODT and 0.5 parts by mass of Omnirad TPO-L were used.

[0079] Example 6: Preparation of photocurable silicone composition 6

[0080] A photocurable silicone composition was prepared in the same manner as in Example 5, except 0.5 parts by mass of a mixture of ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate and bis(2,4,6-trimethylbenzoyl)-phenylphosphinoxide (Omnirad 2100) was used instead of 0.5 parts by mass of Omnirad TPO-L.

[0081] Comparative Example 1: Preparation of photocurable silicone composition 7

[0082] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 41.67 parts by mass of RMS 310 resin / 50.93 parts by mass of MP-153 was used, RMS 313 was not used, and 6.7 parts by mass of DODT was used.

[0083] Comparative Example 2: Preparation of photocurable silicone composition 8

[0084] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 32 parts by mass of RMS 310 resin / 39.1 parts by mass of MP-153 was used, and 15.6 parts by mass of RMS 312 was used instead of RMS 313.

[0085] Comparative Example 3: Preparation of photocurable silicone composition 9

[0086] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 31.45 parts by mass of RMS 310 resin / 38.45 parts by mass of MP-153 was used, and 18.9 parts by mass of pentaerythritol tetrakis(3-mercaptobutylate) (PE-1) was used instead of 12.6 parts by mass of DODT.

[0087] Comparative Example 4: Preparation of photocurable silicone composition 10

[0088] A photocurable silicone composition was prepared in the same manner as in Example 1, except 72.4 parts by mass of MP-153 was used instead of a batch of 34.29 parts by mass of RMS 310 resin / 41.91 parts by mass of MP-153, and 16.4 parts by mass of PE-1 was used instead of 12.6 parts by mass of DODT.

[0089] Comparative Example 5: Preparation of photocurable silicone composition 11

[0090] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 33.21 parts by mass of RMS 310 resin / 40.59 parts by mass of MP-153 was used, and 7.5 parts by mass of DODT and 7.5 parts by mass of PE-1 were used instead of 12.6 parts by mass of DODT.

[0091] Comparative Example 6: Preparation of photocurable silicone composition 12

[0092] A photocurable silicone composition was prepared in the same manner as in Example 1, except 91.36 parts by mass of MP-153 was used instead of 34.29 parts by mass of RMS 310 resin / 41.91 parts by mass of MP-153, RMS 313 was not used, 8.14 parts by mass of PE-1 was used instead of DODT, BHT was not used, and 0.5 parts by mass of Omnirad TPO-L was used.

[0093] Comparative Example 7: Preparation of photocurable silicone composition 13

[0094] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 37.32 parts by mass of RMS 310 resin / 45.61 parts by mass of MP-153 was used, 5.86 parts by mass of DODT was used, and the ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition is 0.45.

[0095] Comparative Example 8: Preparation of photocurable silicone composition 14

[0096] A photocurable silicone composition was prepared in the same manner as in Example 1, except a batch of 28.92 parts by mass of RMS 310 resin / 35.35 parts by mass of MP-153 was used, 24.53 parts by mass of DODT was used, and the ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition is 2.1.

[0097] Comparative Example 9: Preparation of photocurable silicone composition 15

[0098] 85.3 parts by mass of dimethylvinylsiloxy-terminated dimethyl siloxane (hereinafter referred to as "RBL-9119 polymer"), 4 parts by mass of mercaptosiloxane (3.5 mass% of SH content, hereinafter referred to as "Q3-6654"), 5 parts by mass of RMS 313, 5 parts by mass of DODT and 300ppm of 1,2,3-trihydroxybenzene (pyrogallol) were added to a 100 ml dental mixer (Thinky, ARV-310), and mixed at 2000 rpm for 120 seconds.

[0099] Thereafter, 0.7 parts by mass of Omnirad TPO-L was added to the mixture and mixed once again at 2000 rpm for 60 seconds.

[0100] The ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition was 1.2.

[0101] Experimental Example 1: Viscosity measurement of photocurable silicone

[0102] compositions

[0103] For the photocurable silicone compositions according to Examples 1 to 6 and Comparative Examples 1 to 9, the viscosity of each composition was measured at 200 rpm using a Brookfield cone with a CP-52 cone and plate viscometer (model HBDVIII), and the results are shown in Table 1 and Table 2 below.

[0104] Experimental Example 2: Measurement of in-depth curability of photocurable silicone compositions

[0105] Gap tape with a thickness of 500 μm was adhered to three sides of a black acrylic plate, and the photocurable silicone composition according to Example 1 was applied to the central part of the black acrylic plate. Thereafter, the black acrylic plate on which the above composition was applied was covered with a separate black acrylic plate and the black acrylic plate was fixed with a clamp.

[0106] The sample was placed in an ultraviolet curing box (Phoseon technology-Firejet FJ 800) and irradiated with an LED of 10 J / cm2(405 nm). One side of the black acrylic plate was removed and the length of the cured portion was measured. In-depth curability was measured in the same manner for Examples 2 to 6 and Comparative Examples 1 to 9, and the results are shown in Tables 1 and 2 below.

[0107] Experimental Example 3: Measurement of cure rate of photocurable silicone compositions

[0108] For the photocurable silicone composition according to Example 1, a fully cured composition, a composition that was not cured at all, and the actual composition (cured with 350 mJ / cm2energy) were measured with ATR FT-IR (Thermo - Nicolet iS50).

[0109] The cure rate was measured using the height of the silicon vinyl peak (1406 - 1409 cm-1) based on the silicon phenyl peak (1439 cm-1).

[0110] The specific cure rate calculation formula is as follows.

[0111] [Formula 1]

[0112] cure rate (%) = (H0%- Hsample) / (H0%- H100%) x 100

[0113] Herein, H0%= Hat 1406-1409㎝-1 / Hat 1439㎝-1= silicone vinyl peak / silicone phenyl peak,

[0114] H100%= Hat 1406-1409㎝-1 / Hat 1439㎝-1= silicone vinyl peak / silicone phenyl peak,

[0115] Hsample= Hat 1406~1409㎝-1 / Hat 1439㎝-1= silicone vinyl peak / silicone phenyl peak

[0116] The photocurable silicone compositions according to Examples 2 to 6 and Comparative Examples 1 to 9 were measured in the same manner, and the results are shown in Tables 1 and 2 below.

[0117] Experimental Example 4: Measurement of oil bleed-out rate of photocurable silicone compositions

[0118] The photocurable silicone composition according to Example 1 was dropped on one point of each of epoxy, acryl, and aluminium substrates, and cured by irradiating ultraviolet rays with an energy level of 350 mJ / cm2in an ultraviolet curing box.

[0119] The initial diameter of the cured body was measured using a microscope and left for one day at room temperature. Then, the diameter of the cured body was measured again using a microscope, and the degree of oil bleed-out was calculated using the following calculation formula. If the oil bleed-out rate was within 5%, it was evaluated as excellent.

[0120] [Formula 2]

[0121] Oil bleed-out rate (%) = length after one day / initial length x 100

[0122] Oil bleed-out rate was measured in the same manner for Examples 2 to 6 and Comparative Examples 1 to 9, and the results are shown in Tables 1 and 2 below.

[0123] Figure 1 shows the oil bleed-out rate of Example 1 and Comparative Example 9 when an acrylic substrate was used.

[0124]

[0125]

[0126] Regarding the results of Tables 1 and 2, the photocurable silicone compositions according to Examples 1 to 6 had a low viscosity of 500 mPa·s or less, and deep curing was possible to a depth of 20 mm or more. In addition, a high cure rate of more than 95% was achieved, and the oil bleed-out rate was less than 5%, affirming the outstanding effectiveness in suppressing the oil bleed-out phenomenon.

[0127] In contrast, Comparative Examples 1 and 2, which do not comprise the siloxane compound (B) according to the present disclosure, had poor oil bleed-out rates, in particular, Comparative Example 1 had a high viscosity, and Comparative Example 2 had a relatively low cure rate. Comparative Examples 3 and 4, which do not comprise the thiol-based compound (A) according to the present disclosure, and Comparative Example 5, which had a content of the thiol-based compound different from the present disclosure, had a high viscosity, was not capable of deep curing of more than 20 mm, had a low cure rate and had an oil bleed-out phenomenon.

[0128] In addition, Comparative Example 6, which does not comprise the thiol-based compound (A) and the siloxane compound (B) according to the present disclosure and has a different content of organopolysiloxane (C) from the present disclosure, also had a high viscosity, was not capable of deep curing of more than 20 mm, had a low cure rate and had an oil bleed-out phenomenon.

[0129] Meanwhile, Comparative Example 7, in which the SH / Vi ratio in the composition was less than 0.5, had a high viscosity, was impossible to deep cure, had a low curing rate, and had an oil bleed-out phenomenon. Comparative Example 8, in which the SH / Vi ratio in the composition was more than 2, had a low viscosity, but was not capable of deep curing, had a low cure rate, and had an oil bleed-out phenomenon.

[0130] Lastly, Comparative Example 9, which applied the RBL-9119 polymer containing only methyl groups instead of the organopolysiloxane (C) containing methyl and phenyl groups according to the present disclosure, also had poor deep curability, cure rate, and oil bleed-out rate.

Claims

1.A photocurable silicone composition comprising:(A) 8 to 24 wt% of a thiol-based compound containing two or more thiol groups;(B) 5 to 20 wt% of a siloxane compound containing three or more C2-C12alkenyl groups, and a C6-C12aryl group;(C) 15 to 79 wt% of an organopolysiloxane containing vinylsiloxy groups at both ends, represented by Formula 1 below; and(D) 0.01 to 5 wt% of a photoinitiator;based on the total weight of the photocurable silicone composition,wherein the ratio of thiol groups and alkenyl groups (SH / Vi ratio) in the composition is 0.5 to 2.[Formula 1]wherein, R1represents a substituted or unsubstituted C1-C12alkyl group,R2represents a C6-C12aryl group,R3to R6each independently, represent a substituted or unsubstituted C1-C12alkyl group, andn is an integer of 1 to 30.2.A photocurable silicone composition according to claim 1, wherein the thiol-based compound is represented by the following formula:HS-(CH2CH2)a-(OCH2CH2)b-(CH2CH2)c-SHwherein, a and c each independently, represent an integer of 0 to 10, and b is an integer of 1 to 10.3.A photocurable silicone composition according to claim 1, wherein the siloxane compound contains three or more C2-C6alkenyl groups, and a phenyl group.4.A photocurable silicone composition according to claim 1, wherein the siloxane compound is represented by Formula 2 below:[Formula 2]wherein, R7to R12each independently, represent a substituted or unsubstituted C1-C12alkyl group.5.A photocurable silicone composition according to claim 1, wherein, in formula 1,R1represents a substituted or unsubstituted C1-C6alkyl group,R2represents a substituted or unsubstituted phenyl group,R3to R6each independently, represent an unsubstituted C1-C6alkyl group, andn is an integer of 20 to 30.6.A photocurable silicone composition according to claim 1, wherein the photoinitiator absorbs a wavelength of 200 to 450 nm.7.A photocurable silicone composition according to claim 1, wherein the photoinitiator comprises a phosphorus atom.8.A photocurable silicone composition according to claim 1, wherein the photocurable silicone composition further comprises a phenol-based compound substituted with a straight chain or branched chain C1-C6alkyl group, or an unsubstituted polyphenol-based compound.9.A cured body obtained by curing the photocurable silicone composition according to any one of claims 1 to 8.10.An article comprising the cured body according to claim 9.

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