Dual-cure organopolysiloxane compositions with shelf-life stability

Abstract

[Problem] It is an object of the present invention to provide a dual-cure organopolysiloxane composition that is capable of both photocuring and curing by exposure to moisture, that exhibits excellent curability and long-term storage stability at room temperature or ambient storage conditions, and that is preferably applied in a solventless form. [Solution] A dual-cure organopolysiloxane composition, (A) an organopolysiloxane having an average of one or more alkenyl groups per molecule and an average of one or more hydrolyzable groups per molecule; (B) an organopolysiloxane having an average of two or more photoreactive groups per molecule; (C) a condensation reaction catalyst; (D) The following photoinitiators (d1) to (d3): (d1) 2,4,6-trimethylbenzoylphenylphosphinate, (d2) bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and (d3) 2,2-dimethoxy-1,2-diphenylethan-1-one, (E) a silane having an average of two or more hydrolyzable groups per molecule, and optionally (F) a radical scavenger; A dual cure organopolysiloxane composition comprising:

Description

[Technical Field]

[0001] The present invention relates to organopolysiloxane compositions that are capable of both ultraviolet (UV)-induced curing and moisture-induced curing. In particular, the organopolysiloxane compositions have excellent shelf life stability and are preferably used as solventless compositions that do not use substantially any organic solvents. [Background technology]

[0002] Dual-cure organopolysiloxane compositions using UV and moisture cure mechanisms are finding widespread application in electronic articles because they offer the benefits of instant cure through UV primary cure and moisture cure for secondary shadow area cure.

[0003] For example, U.S. Patent No. 5,949,999 discloses dual-cure organopolysiloxane compositions. This reference discloses compositions that are particularly useful for conformal coatings in electronic applications where shadow areas on the substrate do not readily allow for direct UV light and moisture cure is required to crosslink those areas. In addition to the photoinitiator typically present for radiation polymerization, a condensation catalyst, such as an organotitanate or organotin, is also present. Without the condensation catalyst, moisture cure typically does not occur with any degree of certainty or within any predictable time frame. Therefore, as a practical matter, without the condensation catalyst, the moisture cure aspect of these compositions is not practical for commercial use. Furthermore, the compositions lack storage stability at room temperature or ambient storage conditions.

[0004] Similarly, Patent Documents 2 and 3 propose solvent-based dual-cure organopolysiloxane compositions. The combination of a UV-irradiated thiol-ene reaction and a titanium-catalyzed moisture-cure reaction via alkoxy condensation provides excellent curing performance and physical properties in a fresh state. However, to maintain the curing performance and properties, the compositions require storage at low temperature or in a freezer for the duration of their shelf life. While this specific low-temperature storage condition is beneficial for maintaining performance, it also introduces other constraints, such as increased storage costs and additional investments for manufacturers and users, negatively impacting sustainability. Furthermore, these compositions cannot be used in solventless compositions and coating / adhesive applications.

[0005] Thiol-ene based UV and moisture dual cure systems tend to suffer from a relatively short shelf life compared to moisture cure only systems or thiol-ene UV cure only siloxane systems. Shelf life can be assessed by determining whether the composition experiences an increase in viscosity and / or a decrease in cure depth upon UV cure and / or an increase in the time it takes to moisture cure to a tack-free surface after storage compared to when the composition is freshly made.

[0006] US Patent Nos. 5,999,229 and 5,999,233 attempt to address the shelf life issues of thiol-ene based dual cure formulations by providing thiol-ene dual cure organopolysiloxane systems that require an epoxy compound to stabilize the formulation.

[0007] However, the dual-cure organopolysiloxane compositions disclosed in the above patents exhibit insufficient long-term storage stability and shelf life at room temperature or ambient storage conditions. Furthermore, it would be desirable to provide a solvent-free (i.e., substantially free of organic solvents) dual-UV-cure, moisture-cure silicone composition in which curing of the composition with UV results in a coating that is dry to the touch without the typical tacky surface often associated with acrylate curing. [Prior art documents] [Patent documents]

[0008] Patent document 1: U.S. Patent No. 4,528,081 Patent document 2: U.S. Patent No. 6,828,355 Patent Document 3: International Publication No. 2006 / 060189(A2) Patent Document 4: International Publication No. 2019 / 005393(A1) Patent Document 5: International Publication No. 2020 / 076620(A1) Summary of the Invention [Problem to be solved by the invention]

[0009] It is an object of the present invention to provide dual-cure organopolysiloxane compositions capable of both photocuring and curing by exposure to moisture, which exhibit excellent curability and long-term storage stability at room temperature or ambient storage conditions, and which are preferably applied in a solventless form. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have discovered a dual-cure organopolysiloxane composition comprising: (A) an organopolysiloxane having an average of one or more alkenyl groups per molecule and an average of one or more hydrolyzable groups per molecule; (B) an organopolysiloxane having an average of two or more photoreactive groups per molecule; (C) a condensation reaction catalyst; (D) The following photoinitiators (d1) to (d3): (d1) 2,4,6-trimethylbenzoylphenylphosphinate, (d2) bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and (d3) 2,2-dimethoxy-1,2-diphenylethan-1-one, (E) a silane having an average of two or more hydrolyzable groups per molecule, and optionally It has been discovered that the above problems can be solved by a dual-cure organopolysiloxane composition containing (F) a radical scavenger.

[0011] In various embodiments, the mass ratio of the components (d1) to (d3) is within the following ranges, where the total mass of the components (d1) to (d3) is taken as 100 mass %: The mass ratio of component (d1) is in the range of 10 to 30 mass%; The mass ratio of component (d2) is in the range of 20 to 40 mass%; The mass ratio of the component (d3) is in the range of 40 to 80 mass %.

[0012] In certain embodiments, the composition undergoes both UV and moisture cure mechanisms.

[0013] In certain embodiments, the composition is substantially free of organic solvents, i.e., a "solvent-free" composition.

[0014] In certain embodiments, the composition is for use as a potting (or pottant), coating, adhesive, or encapsulant.

[0015] Advantageous Effects of the Invention The dual-cure organopolysiloxane compositions of the present disclosure generally have the ability to cure both by light and by exposure to moisture, and exhibit good to excellent curability and long-term storage stability at room temperature or ambient storage conditions. Furthermore, the compositions can be easily applied in the form of "solventless" compositions with excellent coatability and moderate viscosity.

[0016] Mode of Invention The terms "comprising" or "comprise" are used herein in their broadest sense to mean and encompass the concepts of "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "eg," "such as," and "including" to list examples does not limit the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and encompasses other similar or equivalent examples. As used herein, the term "about" serves to reasonably encompass or describe slight variations in a numerical value determined by instrumental analysis or resulting from sample handling. Such slight variations may be as little as ±0-25%, ±0-10%, ±0-5%, or ±0-2.5% of the numerical value. Furthermore, the term "about" applies to both numerical values ​​when relating to a range of values. Furthermore, the term "about" may be applied to numerical values ​​even if not expressly stated.

[0017] Generally, as used herein, a hyphen "-" or a wavy line "~" in a range of values ​​means "to" or "through," ">" means "above" or "greater-than," "≥" means "at least" or "greater-than or equal to," "<" means "below" or "less-than," and "≤" means "at most" or "less-than or equal to." Each of the foregoing patent applications, patents, and / or patent application publications is expressly incorporated by reference in its entirety herein on an individual basis in one or more non-limiting embodiments.

[0018] It is understood that the scope of the appended claims is not limited to the explicit and specific compounds, compositions, or methods described in the detailed description, which may vary among specific embodiments falling within the scope of the appended claims. With respect to any Markush group relied upon herein to describe specific features or aspects of various embodiments, it should be understood that different, extraordinary, and / or unexpected results can be obtained from each element of the respective Markush group, independently of all other Markush elements. Each element of a Markush group may be relied upon individually and / or in combination to provide adequate support for specific embodiments within the scope of the appended claims.

[0019] Any ranges and subranges relied upon in describing various embodiments of the present invention should also be understood to be within the scope of the appended claims, both individually and inclusively, and all ranges, including integer and / or fractional values, are understood to be described and contemplated therein, even if not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and subranges fully describe and enable various embodiments of the present invention, and that such ranges and subranges may be further subdivided into relevant halves, thirds, fourths, fifths, etc. As merely an example, a range "from 0.1 to 0.9" may be further subdivided into a lower third, i.e., 0.1 to 0.3, a middle third, i.e., 0.4 to 0.6, and an upper third, i.e., 0.7 to 0.9, which are individually and inclusively within the scope of the appended claims and within which specific embodiments may be relied upon and / or relied upon, individually and / or inclusively, to provide sufficient support. Additionally, with respect to words defining or modifying a range, such as "at least," "greater than," "less than," "less than or equal to," etc., such words should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" inherently includes subranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., each of which may be relied upon individually and / or inclusively to provide sufficient support for specific embodiments within the appended claims. Finally, individual numbers within disclosed ranges may be relied upon to provide sufficient support for specific embodiments within the appended claims. For example, the range "from 1 to 9" includes various individual integers, such as 3, as well as individual numbers including decimal points (or fractions), such as 4.1, which may be relied upon to provide sufficient support for specific embodiments within the appended claims.

[0020] <Dual-cure organopolysiloxane composition> Component (A) is an organopolysiloxane having, on average, one or more alkenyl groups per molecule and one or more hydrolyzable groups per molecule. Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups. In certain embodiments, from the standpoint of economy and reactivity, at least one or more of vinyl, allyl, hexenyl, and octenyl groups are present. In particular, in consideration of excellent UV curability of the composition, component (A) may have at least two alkenyl groups per molecule.

[0021] Examples of hydrolyzable groups include alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy. In certain embodiments, from the viewpoints of economy and curability, at least one of methoxy and ethoxy groups is present. In particular, from the viewpoint of excellent moisture-induced curability of the composition, component (B) may have at least two silicon-bonded alkoxy groups per molecule.

[0022] Further examples of groups bonded to silicon atoms in component (A) other than alkenyl and alkoxy groups include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, and xylyl; aralkyl groups having 7 to 12 carbon atoms, such as benzyl and phenethyl; and halogen-substituted alkyl groups having 1 to 12 carbon atoms, such as 3-chloropropyl and 3,3,3-trifluoropropyl. In certain embodiments, methyl groups are present from the standpoints of economy and heat resistance.

[0023] Component (A) can be produced by the hydrosilylation reaction of (A-1) an organopolysiloxane having at least two alkenyl groups per molecule with (A-2) an organosilicon compound having one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable (i.e., alkoxy) group per molecule.

[0024] Component (B) is an organopolysiloxane containing an average of two or more photoreactive groups per molecule. The photoreactive group is most preferably a mercapto (—SH) functional group. Examples of the mercapto functional group include mercaptoalkyl groups such as 3-mercaptopropyl, 4-mercaptobutyl, and 6-mercaptohexyl. Furthermore, examples of groups other than the mercapto functional group bonded to silicon atoms in component (A) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, and xylyl; aralkyl groups having 7 to 12 carbon atoms, such as benzyl and phenethyl; and halogen-substituted alkyl groups having 1 to 12 carbon atoms, such as 3-chloropropyl and 3,3,3-trifluoropropyl. In certain embodiments, methyl groups are present from the standpoint of economy and heat resistance. Furthermore, the silicon atoms in component (B) may be bonded to small amounts of hydrogen atoms, hydroxyl groups, or alkoxy groups, such as methoxy groups, ethoxy groups, n-propoxy groups, i-propoxy groups, n-butoxy groups, sec-butoxy groups, tert-butoxy groups, and the like.

[0025] In various embodiments, component (B) is an organopolysiloxane comprising at least two siloxane units of the following general formula: (HSR 1 )R 2 x SiO (3-x) / 2 .

[0026] In the formula, R 1represents a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include alkylene groups having 1 to 8 carbon atoms, such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, and octylene. In a specific embodiment, a propylene group is present from the viewpoints of economy and heat resistance.

[0027] In the formula, R 2 represents an alkyl group, an aryl group, a hydrogen atom, a hydroxyl group, or an alkoxy group. 2 Examples of the alkyl group include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, and xylyl; and alkoxy groups having 1 to 6 carbon atoms, such as methoxy, ethoxy, and propoxy. In a specific embodiment, a methyl group is present from the viewpoints of economy and heat resistance.

[0028] wherein x is 0, 1, or 2. When "x" is 0, the siloxane unit is a T unit represented by the general formula: HSR 1 SiO 3 / 2 .

[0029] When "x" is 1, the siloxane unit is a D unit represented by the general formula: (HSR 1 )R 2 SiO 2 / 2 .

[0030] When "x" is 2, the siloxane unit is an MT unit represented by the general formula: (HSR 1 )R 2 2SiO 1 / 2 .

[0031] Such component (B) may have mercapto (—SH) groups in a range of about 0.5 to about 15.0% by weight of the component, optionally about 0.5 to about 10.0% by weight, optionally about 1.0 to about 15.0% by weight, optionally about 1.0 to about 10.0% by weight, optionally about 1.0 to about 5.0% by weight, or optionally about 1.0 to about 4.0% by weight. The reason for this is that if the content exceeds the lower limit of the range, the curability of the resulting composition is improved, but on the other hand, if the content is less than the upper limit of the aforementioned range, the heat resistance of the resulting cured product is improved.

[0032] The average number of such photoreactive groups, such as mercapto (-SH) groups, in component (B) is 2 or more, preferably 2 to 10. Most preferably, component (B) has an average of 3 to 8 mercapto (-SH) groups.

[0033] Component (C) is a condensation reaction catalyst for enhancing the moisture cure of the composition. Examples of component (C) include titanium compounds such as tetra(isopropoxy)titanium, tetra(n-butoxy)titanium, tetra(t-butoxy)titanium, di(isopropoxy)bis(ethylacetoacetate)titanium, di(isopropoxy)bis(methylacetoacetate)titanium, and di(isopropoxy)bis(acetylacetonate)titanium; tetra(isopropoxy)zirconium, tetra(n-butoxy)zirconium, tetra(t-butoxy)zirconium, and di(isopropoxy)bis(acetylacetonate). Examples of suitable condensation catalysts include zirconium compounds such as di(isopropoxy)bis(ethylacetoacetate)zirconium, di(isopropoxy)bis(methylacetoacetate)zirconium, and di(isopropoxy)bis(acetylacetonate)zirconium; tin compounds such as dimethyltin dineodecanoate, dibutyltin dilaurate, and dibutyltin dioctoate; and organometallic catalysts (typically titanate-, tin-, or zirconia-based catalysts) including stannous octoate. The condensation catalyst is typically a titanate-, tin-, or zirconium-based catalyst. Examples of suitable condensation catalysts include any one or any combination of more than one condensation catalyst selected from the group consisting of tetraisopropyl orthotitanate, titanium(IV) n-butoxide, titanium(IV) t-butoxide, titanium(IV), titanium di(isopropoxy)bis(ethylacetoacetate), tetrakis(trimethylsiloxy)titanium; titanium di(isopropoxy)bis(methylacetoacetate), zirconium(IV) isopropoxide, zirconium(IV) n-butoxide, zirconium(IV) t-butoxide, zirconium di(isopropoxy)bis(ethylacetoacetate), zirconium di(isopropoxy)bis(methylacetoacetate), zirconium di(isopropoxy)bis(acetylacetonate), dimethyltin dineodecanoate, dibutyltin dilaurate, dibutyltin dioctoate, and stannous octoate.

[0034] The content of component (C) is an amount effective for moisture curing. In various embodiments, component (C) is present in an amount of about 0.01 to about 10 parts by weight, optionally about 0.05 to about 10 parts by weight, or optionally about 0.05 to about 5 parts by weight per 100 parts by weight of the total weight of components (A) through (F). This is because, when the amount of component (C) exceeds the lower limit of the range, the resulting composition cures sufficiently with moisture, and, when the amount is less than the upper limit of the aforementioned range, the surface cure rate of the resulting composition is improved.

[0035] Component (D) is one of the most characteristic features of the present invention and is a limited combination of the following photoinitiators (d1) to (d3): (d1) 2,4,6-trimethylbenzoylphenylphosphinate, (d2) bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and (d3) 2,2-Dimethoxy-1,2-diphenylethan-1-one.

[0036] Component (D) is a limited combination of photoinitiators (d1) to (d3) that enhances the photocuring reaction of the composition, and the entire composition exhibits good to excellent curability and long-term storage (i.e., shelf-life) stability at room temperature or ambient storage conditions. Furthermore, the limited combination of photoinitiators preferably dissolves easily and uniformly without the use of other organic solvents. Therefore, by using the limited combination of photoinitiators (d1) to (d3), "solventless" dual-cure organopolysiloxane compositions can be easily formulated. On the other hand, if any one of the components (d1) to (d3) is not present in the composition, the composition loses any of the advantages of solventless compositions, such as excellent curability, long-term storage (i.e., shelf-life) stability, and good compatibility.

[0037] In various embodiments, the mass ratio of the components (d1) to (d3) is within the following range, where the total mass of the components (d1) to (d3) is 100 mass %: The mass ratio of component (d1) is in the range of 10 to 30 mass%; The mass ratio of component (d2) is in the range of 20 to 40 mass%; The mass ratio of the component (d3) is in the range of 40 to 80 mass %.

[0038] The content of component (D) is an amount effective for photocuring. In various embodiments, component (D) is present in an amount of about 0.01 to about 5 parts by weight, optionally about 0.1 to about 5 parts by weight, or optionally about 0.1 to about 3 parts by weight per 100 parts by weight of the total weight of components (A) to (F). This is because, when the amount of component (D) exceeds the lower limit of the range, the resulting composition is sufficiently cured by ultraviolet light, but, on the other hand, when the amount is less than the upper limit of the aforementioned range, the mechanical properties of the resulting cured product are improved.

[0039] In a preferred embodiment, the composition is substantially free of photoinitiators other than component (D). Specifically, the composition preferably contains no more than 0.1 parts by mass of photoinitiators other than component (D) per 100 parts by mass of the total of components (A) to (F). The content of photoinitiators other than component (D) is preferably no more than 0.01 parts by mass per 100 parts by mass of the total of components (A) to (F), and most preferably below the detection limit.

[0040] Component (E) is a silane having an average of two or more hydrolyzable groups per molecule, which functions as a crosslinker. It can also function as a carrier liquid and / or reactive diluent. Desirably, the hydrolyzable groups are alkoxy groups, more preferably, the hydrolyzable groups are alkoxy groups selected from the group consisting of methoxy, ethoxy, propoxy, and butoxy. The silane may be a dialkoxysilane, a trialkoxysilane, or a combination of a dialkoxysilane and a trialkoxysilane. Most preferably, the silane is a trialkoxysilane.

[0041] The silane preferably has the following structure: R 3 f Si(OR 3 ) 4-f where the subscript f is 1, 2, or 3 (preferably 1 or 2, most preferably 1), and R 3 is independently selected at each occurrence from the group consisting of a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of suitable silane compounds include any one or a combination of two or more selected from methyltrimethoxysilane, ethyltriethoxysilane, and dimethyldimethoxysilane.

[0042] The content of component (E) is an amount effective to function as a crosslinker. In various embodiments, component (E) is present in an amount of about 0.01 to about 10 parts by weight, optionally about 0.05 to about 10 parts by weight, or optionally about 0.05 to about 5 parts by weight per 100 parts by weight of the total of components (A) to (F). This is because when the amount of component (E) exceeds the lower limit of the range, the resulting composition has sufficient cure speed and cure properties.

[0043] Optionally, in order to enhance or improve the long-term stability of the composition, an epoxy-functional organosilicon compound can be incorporated into the composition in combination with component (E) or at least partially replace component (E).Examples of epoxy-functional organosilicon compounds include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, 3,4-epoxybutyltrimethoxysilane, 3,4-epoxybutylmethyldimethoxysilane, 5,6-epoxyhexyltrimethoxysilane, 5,6-epoxyhexyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, etc.; and epoxy-functional non-silicon compounds such as methyl glycidyl ether and glycidyl methacrylate.

[0044] Optionally, as component (F), the composition further comprises a radical scavenger (inhibitor) to inhibit radical reactions during storage and help increase the storage stability of the composition. Examples of suitable radical scavengers include any one or any combination of two or more of butylated hydroxytoluene (BHT), 4-methoxyphenol, and tert-butylhydroquinone, 6-tert-butyl-2,4-xylenol, 2-tert-butyl-1,4-benzoquinone, 4-tert-butylpyrocatechol, 2,6-di-tert-butylphenol, and N-nitroso-N-phenylhydroxyamine aluminum salt.

[0045] The content of component (F) is not limited, but is typically present at a concentration of 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.50% by mass or more, or 1.0% by mass or more, based on the total weight of the composition, and at the same time, is typically present at a concentration of 2.0% by mass or less, 1.5% by mass or less, or 1.0% by mass or less.

[0046] The composition may also contain one or more other additives, such as fillers, adhesion promoters, resins, pigments, moisture scavengers, fluorescent dyes, inhibitors, and other conventional additives, provided they do not interfere with the curing mechanism.

[0047] Fillers such as fumed silica or quartz are contemplated. The filler may be present in an amount up to about 30 weight percent, for example, from about 4 to about 20 weight percent, of the total weight of components (A) through (F).

[0048] The inhibitor may be present in an amount of up to about 5% by weight, e.g., about 0.001 to about 1% by weight, of the total weight of components (A) through (F). The specific amount of inhibitor must be balanced in a given composition to provide or improve the stability of the composition. Such an amount can be determined by routine experimentation.

[0049] The adhesion promoter may be present in an amount up to about 5% by weight, for example about 0.5% by weight, of the total weight of components (A) through (F).

[0050] [Solvent-free Form] The composition is preferably a "solvent-free" type. Preferably, the composition is substantially free of organic solvents, with the preferred organic solvent content being 1.0% by mass or less of the total composition, most preferably below the detection limit. Examples of such organic solvents include, but are not limited to, toluene, xylene, alcohol, and liquid alkanes, as well as other low-viscosity or volatile silicone oils.

[0051] The composition can be prepared by mixing the components together to obtain a substantially homogeneous or uniformly blended material, and can be stored in a container that is impermeable to ultraviolet light and moisture. Generally, a single-package system is utilized, although a two-part package system can be used if desired. The single-package product is ready to use once dispersed, while the two-part system generally requires mixing of the dispersed parts before use.

[0052] The compositions can be used in potting applications, as described above, as well as coatings, encapsulants, and gels for a variety of substrates, including electronic components and other heat-sensitive materials.

[0053] Useful UV radiation sources include conventional mercury vapor lamps, LED curing lamps, etc., which are designed to emit ultraviolet energy in various ultraviolet wavelength bands. For example, a useful radiation wavelength range includes 200-400 nm.

[0054] UV curing typically requires 40 milliwatts / cm 2 ("mW / cm 2 ”) ~ approx. 300mW / cm 2 in the range of, for example, about 70 mW / cm 2 ~About 300mW / cm 2 This is done within the scope of [Example]

[0055] Here, the dual-curing organopolysiloxane composition of the present invention will be described in detail using Examples and Comparative Examples. The aging of the samples was carried out by storing the evaluation samples in an oven at 50 °C for 2 weeks for accelerated aging. UV curing was performed by exposing a sample with a thickness of 1 - 2 mm to a 405 nm or 395 nm UV LED lamp (Phoseon FireJet™ FJ800). For additional exposure to UV LED at 365 nm, the sample was additionally exposed over 1 - 3 J / cm<None (since 2 is just a tag and not text to translate)>to. The measurements are as follows. <None (since 2 is just a tag and not text to translate)>to. <None (since is just a tag and not text to translate)><None (since

[0056] is just a tag and not text to translate)><None (since is just a tag and not text to translate)><Measurement of UV Curing Depth><None (since is just a tag and not text to translate)>The sample is filled into a PE jig with a diameter of 8 mm and a depth of 7 mm. After filling, the sample is exposed to a UV LED lamp of 405 nm or 395 nm at 10 J / cm<None (since 2 is just a tag and not text to translate)>. Then, after taking it out of the jig, the cured thickness is measured by a thickness gauge meter. The threshold value for this property is 5 mm, i.e., > 5 mm. <None (since is just a tag and not text to translate)><None (since

[0057] is just a tag and not text to translate)><None (since is just a tag and not text to translate)><Touch-Dry Time (Moisture Curing Rate)><None (since is just a tag and not text to translate)>The sample is placed in an area without UV light at 22 ± 2 °C and / 50% RH + / - 10%, and then the surface is gently touched with a finger every 5 - 10 minutes. Then, the time when nothing adheres to the finger during touching is measured. The threshold value for this property is 12 hours, i.e., < 12 hours. <None (since is just a tag and not text to translate)><None (since

[0058] is just a tag and not text to translate)><None (since is just a tag and not text to translate)><Shore A Hardness Test><None (since is just a tag and not text to translate)>After the sample is cured by UV exposure, it is laminated to a thickness of more than about 8 mm, and then the Shore A hardness is measured by a Shore A hardness tester. After completion, the tested sample is cured for 3 days under ambient conditions for secondary moisture curing, and then the Shore A hardness is measured in the same way. The threshold value for the difference in Shore A hardness before and after aging for 14 days is 40%, i.e., < 40%. <None (since is just a tag and not text to translate)><None (since

[0059] is just a tag and not text to translate)><None (since is just a tag and not text to translate)><Viscosity Measurement><None (since is just a tag and not text to translate)>Sample viscosity is measured using a Brookfield HADVIII cone-plate viscometer with spindle CPA-52Z at 5 rpm and 23±2° C. The threshold for viscosity difference before and after 14 days of aging is 30%, i.e., <30%.

[0060] <Examples 1 to 5 and Comparative Examples 1 to 7> The dual-cure organopolysiloxane compositions shown in Table 1 (by weight) were prepared using the following ingredients:

[0061] The following organopolysiloxane was used as component (A): (a1): A vinyl and alkoxysilyl functional dimethylpolysiloxane having the following chemical structure: CH2=CH(CHO)SiO(Si(CH2)O) n Si(CH3O)2CH=CH2 (a2): A vinyl and alkoxysilyl functional dimethylpolysiloxane having the following chemical structure: Si[O-(Si(CH3)2O) 30 -Si(CH3)2-CH=CH2]2[O-[Si(CH3)2O] 30 -Si(CH3)2-CH2CH2-Si(CH3)2-O-Si(CH3)2-Si(OCH3)3]2

[0062] The following organopolysiloxanes were used as component (B): (b1): Dimethylsiloxane methyl(3-mercaptopropyl)siloxane copolymer having the following chemical structure: (R2R''SiO 1 / 2 )2(RR'SiO 2 / 2 ) m (R2SiO 2 / 2 ) n (wherein R = R'' = methyl, R' = HS(CH2)2CH2-, and on average n = 43 and m = 5)

[0063] The following condensation reaction catalysts were used as component (C): (c1): Titanium ethylacetoacetate complex mixed with methyltrimethoxysilane (c2): Titanium ethyl acetoacetate complex (c3): Tetra-n-butyl titanate (c4): Tetra t-butyl titanate

[0064] The following photoinitiators were used as component (D): (d1): 2,4,6-trimethylbenzoylphenylphosphinate (d2): Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (d3): 2,2-dimethoxy-1,2-diphenylethan-1-one (d4): 2-hydroxy-2-methylpropiophenone (d5): 2,4,6-trimethylbenzoyldiphenylphosphinate

[0065] The following silanes were used as component (E): (e1): Methyltrimethoxysilane (e2): Dimethyldimethoxysilane (e3): dimethyldiethoxysilane

[0066] The following radical scavengers were used as component (F): (f1): Butylated hydroxytoluene (f2): N-nitroso-N-phenylhydroxylamine aluminum salt

[0067] The component "filler" used was: hexamethyldisilazane treated fumed silica.

[0068] The following was used as the component "adhesion promoter": aminopropyltrimethoxysilane reacted with glycidoxypropyltrimethoxysilane and methyltrimethoxysilane.

[0069] The component "silicone resin" used was: silicic acid, sodium salt, reaction product with chlorotrimethylsilane.

[0070] [Table 1-1]

[0071] [Table 1-2] * A mixture of components (f1) and (f2) in a mass ratio of (f1) / (f2)=83 / 17

[0072] [Table 2-1]

[0073] [Table 2-2]

[0074] [Table 2-3] [Industrial Applicability]

[0075] The dual-cure organopolysiloxane compositions of the present disclosure can be cured both by light curing and by exposure to moisture, and exhibit good to excellent curability and long-term storage stability at room temperature or ambient storage conditions. Furthermore, the compositions of the present disclosure can be easily applied in the form of a "solvent-free" composition with excellent coatability and moderate viscosity. Therefore, the compositions can be used as potting compositions, coatings, adhesives, and encapsulants.

Claims

1. 1. A dual cure organopolysiloxane composition comprising: (A) an organopolysiloxane having an average of one or more alkenyl groups per molecule and an average of one or more hydrolyzable groups per molecule; (B) an organopolysiloxane having an average of two or more photoreactive groups per molecule; (C) a condensation reaction catalyst; (D) the following photoinitiators (d1) to (d3): (d1) 2,4,6-trimethylbenzoylphenylphosphinate, (d2) bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and (d3) 2,2-dimethoxy-1,2-diphenylethan-1-one; (E) a silane having an average of two or more hydrolyzable groups per molecule, and optionally (F) a radical scavenger; A dual cure organopolysiloxane composition comprising:

2. The mass ratio of the components (d1) to (d3) is within the following range, when the total mass of the components (d1) to (d3) is taken as 100 mass%, i.e., The mass ratio of component (d1) is in the range of 10 to 30 mass%; The mass ratio of component (d2) is in the range of 20 to 40 mass%; 2. The dual-cure organopolysiloxane composition according to claim 1, wherein the weight ratio of component (d3) is in the range of 40 to 80 weight percent.

3. 10. The dual cure organopolysiloxane composition of claim 1 obtained from both a UV radical cure mechanism and a moisture cure mechanism.

4. 10. The dual-cure organopolysiloxane composition of claim 1, which is substantially free of organic solvents.

5. 10. The dual-cure organopolysiloxane composition of claim 1 for use as a potting composition, coating, adhesive, or encapsulant.

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