Silicone pressure-sensitive adhesive composition and article containing the same

Abstract

To provide a silicone pressure-sensitive adhesive composition which comprises an alternative additive or an additive system providing the silicone pressure-sensitive adhesive composition with improved adhesion to a low energy surface, especially at relatively low additive loading.SOLUTION: The present invention provides a silicone pressure-sensitive adhesive composition comprising: at least one boron-containing additive comprising a cyclic borate; and at least one element selected from the group consisting of i) boric acid and ii) an acyclic borate compound. The present invention also provides an article such as a pressure-sensitive adhesive tape comprising the silicone pressure-sensitive adhesive composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a silicone pressure-sensitive adhesive (PSA) composition, and more particularly to a silicone PSA composition having improved adhesion, especially to low-energy surfaces. The present invention also relates to an article comprising a silicone pressure-sensitive adhesive composition. [Background technology]

[0002] Pressure-sensitive adhesives (PSAs) are widely used in various applications. Among the various types of PSAs, silicone PSAs are gaining attention due to their resistance to extremely high and extremely low temperatures, applicability to high-energy and low-energy surfaces, and excellent insulating properties. Although silicone PSAs are applicable to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials, the adhesion they provide to such surfaces is low if no surface treatment is performed, typically showing an adhesion of less than 300 gf / in when peeled at a 180° angle, as determined by the FINAT test method No. 1.

[0003] To increase the adhesion of silicone PSA to such low-energy surfaces, additives such as trialkyl borate (often tri-n-butyl borate) are incorporated into the silicone PSA. While the addition of trialkyl borate can increase adhesion, the resulting adhesion remains insufficient when added in amounts conventionally used for PSA. Adhesion can increase with increasing amounts of trialkyl borate. However, from the standpoint of compatibility with PSA in the case of high-filling, the use of large amounts of trialkyl borate is undesirable.

[0004] Therefore, there is a need for the development of silicone pressure-sensitive adhesive compositions that include alternative additives or additional systems that provide improved adhesion to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials, particularly with relatively small amounts of additives. [Overview of the project]

[0005] In one embodiment, the present invention provides a silicone pressure-sensitive adhesive composition comprising at least one boron-containing additive, which comprises a boron-containing compound selected from the group consisting of boroxine-based compounds and borane-based compounds containing a boron-nitrogen covalent bond.

[0006] In another embodiment, the present invention provides a silicone pressure-sensitive adhesive composition comprising at least one boron-containing additive, comprising at least two elements selected from the group consisting of i) boroxine compounds, borane compounds containing boron-nitrogen covalent bonds, or cyclic borate compounds; ii) boric acid; and iii) acyclic borate compounds.

[0007] In yet another embodiment, the present invention provides an article comprising a silicone pressure-sensitive adhesive composition according to the above-described embodiment.

[0008] According to the present invention, the silicone pressure-sensitive adhesive composition containing the boron-containing additive described above provides improved adhesion to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials under the same conditions, compared to the corresponding silicone pressure-sensitive adhesive composition containing a conventional trialkyl borate additive. [Brief explanation of the drawing]

[0009] Figure 1 is a bar graph showing the peel-off adhesive strength of adhesive tapes measured 20 minutes, 24 hours, and 72 hours after application to silicone rubber, where the tapes were coated with a pressure-sensitive adhesive composition, freshly prepared as described in Example 11, or aged for 8 weeks at room temperature and 40°C.

[0010] Figure 2 is a bar graph showing the peel-off adhesive strength of silicone pressure-sensitive adhesive compositions without additives, or pressure-sensitive adhesive compositions containing various amounts of tributyl borate and trimethoxyboroxine.

[0011] Figure 3 is a graph showing the change in peel force over time at room temperature for the silicone pressure-sensitive adhesive tapes prepared in the reference example and Example 23.

[0012] Figure 4 is a graph showing the change in peel force at 40°C over time for the silicone pressure-sensitive adhesive tapes prepared in the reference example and Example 23. [Modes for carrying out the invention]

[0013] In the specification and claims of this application, the following terms and expressions are understood to be as shown:

[0014] The singular forms "aru" (to be), "hitotsu" (one), and "sono" (that) include the plural form unless the context clearly indicates otherwise, and references to a specific number include at least that specific number.

[0015] Any examples or illustrative terms (e.g., "like") provided herein are intended solely to clarify the invention and, unless otherwise specified, do not limit the scope of the invention.

[0016] No word in this specification should be understood to indicate that any non-claimed element is essential to the implementation of the invention.

[0017] The terms “include,” “incorporate,” “contain,” and their grammatical equivalents are comprehensive or unrestrictive terms that do not exclude additional, undescribed elements or methodological processes, but are understood to also include the more restrictive terms “consist of” and “essentially consist of.”

[0018] Except in the examples, or unless otherwise specified, all numerical values ​​expressed in the specification and claims, such as quantities of material, temperatures, durations of time, quantified properties of material, and others, shall be understood in all cases as being modified by the term "about," whether or not the term "about" is used in the expression.

[0019] It is understood that all numerical ranges described herein include all subranges within that range, as well as any combination of various endpoints of such ranges or subranges.

[0020] To further understand, any compound, material, or substance explicitly or implicitly disclosed in the specification and / or described in the claims as belonging to a group of compounds, materials, or substances that are structurally, compositionally, and / or functionally related includes individual representative examples of that group and all combinations thereof.

[0021] The term "alkyl" as used in this application means any monovalent saturated linear or branched hydrocarbon group having up to about 30 carbon atoms, more specifically 1 to about 20 carbon atoms, and more specifically 1 to about 10 carbon atoms, and optionally substituted with one or more halogen atoms such as fluorine, chlorine, bromine, and iodine atoms. Examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl such as n-hexyl, heptyl such as n-heptyl, octyl such as n-octyl, isooctyl and 2-ethylhexyl, nonyl such as n-nonyl, and decyl such as n-decyl.

[0022] In this application, the term "alkoxy" refers to a monovalent group that is -O-alkyl, where alkyl is defined as described above.

[0023] As used in this application, the term "hydroxyalkyl" means any alkyl group (as defined above) in which one or more hydrogen atoms are substituted by an equal number of hydroxyl groups. Examples of hydroxyalkyls include any alkyl group (as defined above) in which one of the hydrogen atoms bonded to the terminal carbon atom is substituted by one hydroxyl group in the form of -alkyl-OH.

[0024] As used in this application, the term "alkoxyalkyl" means any alkyl group (as defined above) in which one or more hydrogen elements are substituted by an equal number of alkoxy groups (as defined above). Examples of alkoxyalkyls include any alkyl group (as defined above) in which one of the hydrogen elements bonded to the terminal carbon atom is substituted by one alkoxy group in the form of -alkyl-O-alkyl.

[0025] As used in this application, the term "aryl" means any monovalent aromatic hydrocarbon group having about 6 to about 30 carbon atoms, more specifically about 6 to about 20 carbon atoms, and more specifically about 6 to about 12 carbon atoms, including alkylaryl and arylalkyl. Examples of aryls include phenyl, naphthalenyl, benzyl, phenethyl, o-, m- and p-tolyl and xylyl.

[0026] As used in this application, the term “divalent linking group” means any divalent saturated linear or branched hydrocarbon group having up to about 30 carbon atoms, more specifically 1 to about 20 carbon atoms, and more specifically 2 to about 10 carbon atoms, and optionally containing one or more heteroatoms selected from the group consisting of oxygen, nitrogen, silicon, sulfur, fluorine, chlorine, bromine, and iodine atoms. Examples of divalent linking groups include alkylenes, oxyalkylene groups, and thioalkylenes.

[0027] As used in this application, the term "cyclic" refers to a compound comprising any molecule having at least three atoms bonded together to form a ring (excluding a phenyl ring). This ring may be, for example, a 3-membered to 10-membered ring, more specifically a 4-membered to 8-membered ring, and more specifically a 4-membered, 5-membered, 6-membered, 7-membered, or 8-membered ring.

[0028] As used in this application, the term "acyclic" refers to a compound that does not contain a cyclic structure (excluding a phenyl ring). For example, in some embodiments, the acyclic compounds in this application may have a benzyl group or a phenyl group.

[0029] Unless otherwise specified, the viscosities described herein have been measured at 25°C using a Brookfield viscometer.

[0030] In one embodiment, the present invention provides a silicone pressure-sensitive adhesive composition comprising at least one boron-containing additive. The boron-containing additive comprises a boron-containing compound selected from the group consisting of boroxine-based compounds and borane-based compounds containing a boron-nitrogen covalent bond.

[0031] As used herein, the "boroxine-based compound" refers to a compound having a six-membered ring formed by three alternating boron atoms and three alternating oxygen atoms bonded to each other.

[0032] As used herein, the "borane-based compound containing a boron-nitrogen covalent bond" has the formula Chemical Formula refers to an organoboron compound containing one boryl group, wherein the boryl group is at least directly bonded to one nitrogen atom via a covalent bond.

[0033] In one embodiment, the boroxine-based compound may have general formula (I): Chemical Formula wherein R 1 , R 2 and R 3 are each independently a hydrogen atom; hydroxyl; or a monovalent group having up to about 30 carbon atoms, specifically up to about 20 carbon atoms, more specifically up to about 10 carbon atoms, selected from the group consisting of alkyl groups, alkoxy groups, hydroxylalkyl, and alkoxyalkyl, or -R 8 -N(R 9 )(R 10 ), wherein R 8 is a direct bond or a divalent linking group, and R 9 and R 10 are each independently a hydrogen atom, alkyl, hydroxylalkyl, or alkoxyalkyl; preferably R 1 , R 2 and R3 Each of these groups independently has up to approximately 20 carbon atoms and is a monovalent group selected from the group consisting of alkoxy groups and alkoxyalkyl groups, or -R 8 -N(R 9 )(R 10 ) and here R 8 R is a direct bond, an alkylene group, or an oxyalkylene group (where the oxy group is bonded to the nitrogen atom via the alkylene), 9 and R 10 Each is independently a hydrogen atom, an alkyl group, or an alkoxyalkyl group; more preferably a monovalent group selected from the group consisting of alkoxy groups having up to about 10 carbon atoms, specifically 1 to about 8 carbon atoms, more specifically 1 to about 6 carbon atoms, or -R 8 -N(R 9 )(R 10 ) and here R 8 R is an oxyalkylene group having a direct bond or about 2 to about 6 carbon atoms, and 9 and R 10 Each of these is independently a hydrogen atom, an alkyl group having 1 to about 6 carbon atoms, or an alkoxyalkyl group having 2 to about 8 carbon atoms.

[0034] In one preferred embodiment, the boroxine compound may have general formula (I-1): [ka] R in the formula 11 , R 12 and R 13 Each of these groups independently has up to approximately 20 carbon atoms and is a monovalent group selected from the group consisting of alkyl groups, or -R 14 -N(R 15 )(R 16 ) and here R 14 is an alkylene group, and R 15 and R 16 Each is independently a hydrogen atom, an alkyl group, or an alkoxyalkyl group; and preferably, R 11 , R 12and R 13 Each of these is an alkyl group having 1 to about 10 carbon atoms, preferably 1 to about 8 carbon atoms, and more preferably 1 to about 6 carbon atoms.

[0035] In another preferred embodiment, the boroxine compound may have general formula (I-2):

[0036] [ka] R in the formula 17 Each is independently an alkyl or alkoxyalkyl group having up to 20 carbon atoms, or a hydrogen atom; preferably R 17 Each of these is an alkyl group having a hydrogen atom or up to 10 carbon atoms, preferably 1 to about 8 carbon atoms, and more preferably 1 to about 6 carbon atoms.

[0037] Boroxine compounds may be prepared by various methods known in the art. For example, boroxine compounds may be prepared by heating a substituted boronic acid to form a boroxine compound having the corresponding substituent on the B atom; or by reacting triorganoborane with boric acid to give the corresponding boroxine compound. In a further example, a boroxine compound having formula (I-1) can also be prepared by reacting boric acid with trialkyl borate in stoichiometric ratios.

[0038] In another embodiment, a borane compound containing a boron-nitrogen covalent bond may have general formula (II): [ka] R in the formula 4 and R 5Each independently has up to approximately 30 carbon atoms, more specifically up to approximately 20 carbon atoms, and more specifically up to approximately 10 carbon atoms, and is a monovalent group selected from the group consisting of alkyl groups, alkoxy groups, hydroxylalkyl groups, and alkoxyalkyl groups, or -R 8 -N(R 9 )(R 10 ) and here R 8 is a direct bond or a divalent linking group, and R 9 and R 10 Each of these is independently a hydrogen atom, an alkyl group, a hydroxylalkyl group, or an alkoxyalkyl group; preferably R 4 and R 5 Each of these groups independently has up to approximately 20 carbon atoms and is a monovalent group selected from the group consisting of alkoxy groups, or -R 8 -N(R 9 )(R 10 ) and here R 8 R is a direct bond or an alkylene group, and 9 and R 10 Each of these is independently a hydrogen atom, an alkyl group, or an alkoxyalkyl group; more preferably R 4 and R 5 Each of these is independently an alkoxy group having up to about 10 carbon atoms, more specifically 1 to about 8 carbon atoms, and more specifically 2 to about 6 carbon atoms, or -R 8 -N(R 9 )(R 10 ) and here R 8 is a direct bond, and R 9 and R 10 Each is independently an alkyl having a hydrogen atom or up to about 10 carbon atoms, more specifically 1 to about 8 carbon atoms, and more specifically 1 to about 6 carbon atoms; optionally R 4 and R 5 It comprises an alkylene group having up to 10 carbon atoms, preferably about 2 to about 6 carbon atoms, and more preferably about 2 to about 5 carbon atoms, bonded to the B atom of formula (II) via an oxygen atom; and R 6 and R 7Each is independently an alkyl, hydroxyalkyl, or alkoxyalkyl, each independently having up to about 30 carbon atoms, more specifically up to about 20 carbon atoms, and more specifically up to about 10 carbon atoms, or hydrogen atoms; preferably R 6 and R 7 Each of these is an alkyl group that independently has a hydrogen atom or up to about 10 carbon atoms, more specifically 1 to about 8 carbon atoms, and more specifically 1 to about 6 carbon atoms.

[0039] In one preferred embodiment, the borane compound containing the boron-nitrogen covalent bond may have the general formula (II-1): [ka] R in the formula 21 , R 22 , R 23 , R 24 , R 25 and R 26 Each is independently an alkyl, hydroxyalkyl, or alkoxyalkyl, and each independently has up to about 20 carbon atoms or hydrogen atoms; preferably R 21 , R 22 , R 23 , R 24 , R 25 and R 26 Each of these is independently an alkyl or hydrogen atom having up to about 10 carbon atoms; more preferably an alkyl having up to about 10 carbon atoms, preferably 1 to about 8 carbon atoms, and more preferably 1 to about 6 carbon atoms.

[0040] In another preferred embodiment, the borane compound containing the boron-nitrogen covalent bond may have the general formula (II-2): [ka] R in the formula 27 and R 28each independently represents alkyl having up to 20 carbon atoms, or -R 31 -N(R 32 )(R 33 ) is a monovalent group selected from the group consisting of, wherein R 31 is an alkylene group, and R 32 and R 33 each independently represent a hydrogen atom, alkyl, or alkoxyalkyl; preferably R 27 and R 28 each independently represent alkyl having up to 10 carbon atoms, preferably from 1 to about 8 carbon atoms, and more preferably from 1 to about 6 carbon atoms; optionally R 27 and R 28 together form a ring, comprising an alkylene group having from about 1 to about 6 carbon atoms, preferably from about 2 to about 6 carbon atoms, and more preferably from about 2 to about 5 carbon atoms bonded to the O atom of formula (II-2); preferably R 27 and R 28 together form a ring, comprising CH2CH2-, -CH2CH2CH2-, -CH2CH(CH3)-, -CH(CH3)CH(CH3)-, -CH2CH(CH3)CH2-, or -CH2C(CH3)2CH2- bonded to the O atom of formula (II-2); and in the formula R 29 and R 30 each independently represent alkyl, hydroxyalkyl or alkoxyalkyl, each of which independently has up to 20 carbon atoms, or a hydrogen atom; preferably alkyl having up to about 10 carbon atoms, or a hydrogen atom; more preferably alkyl having up to about 10 carbon atoms, preferably from 1 to about 8 carbon atoms, and more preferably from 1 to about 6 carbon atoms.

[0041] Borane compounds containing a boron-nitrogen covalent bond may be prepared by various methods known in the art. For example, the boron-nitrogen covalent bond in a borane compound may be introduced by reacting a borane halide with a corresponding secondary amine compound, thereby substituting the halogen atom bonded to the boron atom with the corresponding amino group. Furthermore, the boron-oxygen bond in a borane compound having a boron-nitrogen covalent bond can be introduced, for example, by subjecting a tri(dialkylamino)borane compound to an alcohol-amine exchange reaction with an aliphatic alcohol compound. As an example, a borane compound having formula (II-2) can be prepared by reacting tri(dimethylamino)borane with a monohydric alcohol in stoichiometric ratios to form an acyclic compound, or by reacting it with an alkylene glycol in stoichiometric ratios to form a cyclic compound. As a reference, we can cite "Chemistry of Certain Novel Organoboron Compounds" by Gerard W. et al., Chemistry & Industry, 292-3 (1958), which is incorporated in its entirety by reference.

[0042] At least one boron-containing additive, selected from boroxine-based compounds and borane-based compounds, may be present in an amount of about 0.01 to about 10% by weight, preferably about 0.05 to about 9% by weight, and more preferably 0.1 to about 8% by weight, based on the total weight of the silicone pressure-sensitive adhesive composition.

[0043] The boroxine compounds defined above under formula (I), or the borane compounds containing a boron-nitrogen covalent bond defined under formula (II), increase the peel-off adhesion of the silicone pressure-sensitive adhesive composition of the present invention to silicone rubber by at least about 45%, about 65% or more in some embodiments, and about 80% or more, or even 100% or more in further embodiments, compared with conventional trialkyl borate additives under the same conditions.

[0044] In other embodiments, at least one boron-containing additive is: i) boroxine compounds, borane compounds containing a boron-nitrogen covalent bond, or cyclic borate compounds; ii) boric acid; and iii) acyclic borate compounds comprises at least two elements selected from the group consisting of (hereinafter referred to as a first element and a second element).

[0045] As used herein, the term "cyclic borate" refers to a cyclic ester or salt of boric acid (H3BO3), alkylboronic acid or arylboronic acid. As used herein, the terms "alkylboronic acid" and "arylboronic acid" refer to alkyl-substituted or aryl-substituted boric acid compounds, wherein one of the three hydroxyl groups bonded to the boron atom is substituted with alkyl having 1 to about 6 carbon atoms or aryl having about 6 to about 12 carbon atoms, respectively. A cyclic borate may contain 1, 2, or 3 rings per molecule.

[0046] In one embodiment, the cyclic borate compound may have the general formula (III):

Chemical Formula

[0047] In one embodiment, the cyclic borate compound is selected from compounds having formula (III), where R 34 and R 35 Each is independently an alkyl having 1 to 6 carbon atoms, preferably an alkyl having 1 to 4 carbon atoms; L 1 and L 2 Each of these is independently expressed in formula -[C(O)] m C n H 2n A divalent base having -, where m is 0 or 1 and n is an integer from 0 to 3, but m+n is at least 1. Preferably, L 1 and L 2 Each of these is independently a divalent group -CH2-, -CH2CH2-, -CH(CH3)-, -C(CH3)2-, -C(O)-, or -C(O)CH2-.

[0048] In another embodiment, the cyclic borate compound may have general formula (III-1): [ka] L in the ceremony 1 and L 2 Each of these is independently expressed in formula -[C(O)] m C n H 2n A divalent base having -, where m is 0 or 1 and n is an integer from 0 to 3, but m+n is at least 1; preferably, L 1 and L 2 Each of these is independently a divalent group -CH2-, -CH2CH2-, -CH(CH3)-, -C(CH3)2-, -C(O)-, or -C(O)CH2-; L 3These are -CH2-, -CH2CH2-, -CH(CH3)-, or -C(CH3)2-.

[0049] Cyclic borate compounds can be prepared by reacting, for example, boric acid, alkylboric acid (such as methylboric acid or ethylboric acid), or arylboric acid (such as phenylboric acid) with an amine compound containing one to three hydroxyl groups, one or two carboxyl groups, or a combination thereof. Examples of such amine compounds include, but are not limited to, tri(hydroxyalkyl)amines such as triethanolamine, tri-n-propanolamine, or tri-iso-propanolamine; hydroxylalkyliminodicarboxylic acids such as (2-hydroxyethyl)iminodiacetic acid; and alkyliminodicarboxylic acids such as N-methyliminodiacetic acid or N-ethyliminodiacetic acid.

[0050] As used in this application, the term "acyclic borate" refers to acyclic compounds derived from boric acid, among which trialkyl borates are typically well known in the art. Each alkyl group of trialkyl borate may independently have 1 to about 20 carbon atoms, more specifically 1 to about 10 carbon atoms, and more specifically 1 to about 6 carbon atoms. As used in this application, the term "trialkyl borate" includes both single trialkyl borates and mixtures of trialkyl borates having different alkyl groups. Examples of acyclic borate compounds include, but are not limited to, trimethyl borate, triethyl borate, tri-n-propyl borate, tri-isopropyl borate, tri-n-butyl borate, tri-isobutyl borate, trioctyl borate, tridodecyl borate, trioctadecyl borate, or combinations thereof; trimethyl borate, triethyl borate, tri-n-propyl borate, tri-isopropyl borate, tri-n-butyl borate, tri-isobutyl borate, or combinations thereof.

[0051] Acyclic borate compounds and boric acid may be collectively referred to as acyclic boron compounds in this application.

[0052] In one embodiment, the boron-containing additive comprises one or more of the compounds in i) above as a first element and one or more of the compounds in ii) above as a second element; or comprises one or more of the compounds in i) above as a first element and one or more of the compounds in iii) above as a second element; or comprises ii) above as a first element and one or more of the compounds in iii) above as a second element. Examples of boron-containing additives according to this embodiment include, but are not limited to: a combination of a boroxine compound having formula (I) as a first element and trialkyl borate as a second element; a combination of a boroxine compound having formula (I) as a first element and boric acid as a second element; a combination of a borane compound containing a boron-nitrogen covalent bond having formula (II) as a first element and trialkyl borate as a second element; a combination of a borane compound containing a boron-nitrogen covalent bond having formula (II) as a first element and boric acid as a second element; a combination of boric acid as a first element and trialkyl borate as a second element; a combination of a cyclic borate as a first element and trialkyl borate as a second element; and a combination of a boroxine compound having formula (I) as a first element and a borane compound containing a boron-nitrogen covalent bond having formula (II) as a first element and trialkyl borate as a second element. The boron-containing additive in this embodiment provides the silicone pressure-sensitive adhesive composition with improved adhesion to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials.

[0053] In one embodiment, the boron-containing additive comprises a boroxine compound having formula (I), a cyclic borate compound, boric acid, or a combination thereof as a first element; and an acyclic borate compound selected from trialkyl borates as a second element. Examples of boron-containing additives according to this embodiment include, but are not limited to: a combination of a boroxine compound having formula (II) as the first element and trialkyl borate as the second element; a combination of boric acid as the first element and trialkyl borate as the second element; and a combination of a cyclic borate compound having formula (III) as the first element and trialkyl borate as the second element. The two elements in the boron-containing additive according to this embodiment provide a synergistic effect in improving the adhesion of silicone pressure-sensitive adhesive compositions to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials.

[0054] In another embodiment, the boron-containing additive comprises boric acid, a cyclic borate compound having formula (III-I), or a combination thereof as a first element; and an acyclic borate compound, particularly trialkyl borate, as a second element. These two elements achieve a remarkable synergistic effect in improving the adhesion of silicone pressure-sensitive adhesive compositions to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials.

[0055] In another embodiment, the boron-containing additive comprises a boroxine-based compound having formula (II) as the first element and a trialkyl borate as the second element. These two elements achieve a remarkable synergistic effect in improving the adhesion of the silicone pressure-sensitive adhesive composition to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials. In addition, the silicone pressure-sensitive adhesive composition containing the boron-containing additive according to this embodiment has a transparent appearance and long-term stability.

[0056] The weight ratio of the first element to the second element may vary over a wide range. Typically, the weight ratio (first element:second element) may range from about 1 to about 1:1, preferably from about 1:70 to about 1:1. The weight ratio (first element:second element) may be, for example, about 1:60 to about 1:2, for example, about 1:50 to about 1:3, or in another embodiment, about 1:40 to about 1:4.

[0057] In other embodiments, the boron-containing additive may contain all three elements i), ii), and iii) described above. Preferably, an acyclic borate compound iii), particularly trialkyl borate, is present in an amount of about 50 wt% to about 99 wt%, and specifically about 60 wt% to about 98 wt%, relative to the total weight of the boron-containing additive.

[0058] In addition to at least one boron-containing additive, the silicone pressure-sensitive adhesive composition further comprises a silicone pressure-sensitive adhesive (silicone PSA). This silicone PSA may be any known in the art. The silicone PSA generally comprises polyorganosiloxane rubber and silicone resin; and optionally further comprises a curing catalyst, solvent, filler, and other optional components (one or more) as needed. The pressure-sensitive adhesive composition may be cured by a radical reaction or a hydrosilylation reaction.

[0059] As used in this application, the term "polyorganosiloxane rubber" refers to a polyorganosiloxane having a viscosity of at least about 300,000 cps, more specifically from about 500,000 cps to about 150,000,000 cps, more specifically from about 1,000,000 cps to about 100,000,000 cps, and even more specifically from about 2,000,000 cps to about 80,000,000 cps. This polyorganosiloxane rubber may have a number-average molecular weight of at least 100,000, more specifically from about 120,000 to about 1,000,000, and more specifically from about 150,000 to about 800,000. Polyorganosiloxane rubber may contain one or more functional groups selected from the group consisting of hydroxyl, vinyl, alkenyl, alkoxy, alkoxyalkenyl, and hydride.

[0060] A suitable polyorganosiloxane rubber often has the following general formula: R2R F SiO(R2SiO) x (RR F SiO) y SiR F R2(IV) In the formula, R is independently a monovalent hydrocarbon group having up to about 12 carbon atoms, an alkyl group having 1 to about 6 carbon atoms such as methyl, ethyl, and propyl; or an aryl group having about 6 to about 12 carbon atoms such as phenyl; R F Each is independently an alkenyl, alkoxy, or alkoxyalkenyl group such as a hydroxyl, halide, or vinyl, having 1 to about 10 carbon atoms; x and y are independently positive numbers from 0 to 10000, more specifically from 1 to about 8000, and more specifically from 10 to about 5000, where x+y is at least 1000.

[0061] Examples of polyorganosiloxane rubbers include, but are not limited to, polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane-polydiphenylsiloxane copolymers, and vinyl-functionalized polyorganosiloxanes.

[0062] The term "silicone resin" as used in this application means at least one (RSiO 3 / 2 ) or (SiO 4 / 2 ) refers to any organopolysiloxane containing siloxy units. In one embodiment, the silicone resin is given by the formula M=R3SiO 1 / 2 At least one M unit, and the formula T=RSiO 3 / 2 The units of T are and the formula Q = SiO 4 / 2 It includes at least one unit selected from the group consisting of Q units, and optionally the formula D=R2SiO 2 / 2 It comprises at least one D unit, where R is independently a monovalent hydrocarbon group of 1 to about 6 carbon atoms, an alkyl group of 1 to about 4 carbon atoms such as methyl, or a phenyl group.

[0063] The molecular weight of the silicone resin is not limited and may vary over a wide range. For example, the silicone resin may have a number average molecular weight of about 300 or more, more specifically from about 500 to about 50,000, and more specifically from about 1,000 to about 30,000.

[0064] In one embodiment, the silicone resin is an MQ resin comprising at least one Q unit and at least one M unit. The ratio of M units to Q units may be, for example, about 0.5:1 to about 1.5:1, specifically about 0.6:1 to about 1.2:1, more specifically about 0.7:1 to about 1.1:1, and even more specifically about 0.85:1 to about 1.0:1. The MQ resin may further contain D units, T units, or both in amounts of, for example, 20 mol% or less, specifically 10 mol% or less, and more specifically 5 mol% or less, of the total number of units in the silicone resin.

[0065] Generally, MQ resins may be functionalized with hydroxyl groups. The total hydroxyl content in MQ resins is typically about 1–10% by weight, specifically about 2–8% by weight, and more specifically about 2–5% by weight. MQ resins may also be optionally functionalized with one or more functional groups selected from the group consisting of vinyl-like alkenyls, alkoxys, alkoxyalkenyls, and hydrides.

[0066] In another embodiment, the silicone resin is an MT resin containing at least one T unit and at least one M unit, preferably an MDT resin further containing at least one D unit in addition to the T and M units. The MT resin and MDT resin may also contain Q units. The amounts of T units and D units (if present) may be, for example, 60 mol% or more, specifically 70 mol% or more, and more specifically 80 mol% or more, of the total number of units in the silicone resin.

[0067] In MT or MDT resins, the molar ratio of hydrocarbon group "R" to Si atoms (R / Si) is typically about 1.0:1 to about 1.8:1, specifically about 1.1:1 to about 1.7:1, and more specifically about 1.2:1 to about 1.6:1. In some cases, the hydrocarbon group "R" contains methyl and phenyl (Ph) in a ratio of phenyl to hydrocarbon group (Ph / R) of, for example, about 0.1:1 to about 0.8:1, preferably about 0.2:1 to about 0.7:1, and more preferably about 0.2:1 to about 0.6:1.

[0068] MT resins or MDT resins may optionally be functionalized with one or more functional groups selected from the group consisting of hydroxyl, vinyl, alkenyl, alkoxy, alkoxyalkenyl, and hydride.

[0069] The silicone resin may be present in the silicone pressure-sensitive adhesive composition in an amount of about 50 to about 150 parts by weight, more specifically about 70 to about 130 parts by weight, and more specifically about 80 to about 120 parts by weight, per 100 parts by weight of polyorganosiloxane rubber.

[0070] Numerous suitable silicone pressure-sensitive adhesives containing both polyorganosiloxane rubber and silicone resin are commercially available. Examples of these silicone pressure-sensitive adhesives include, but are not limited to, SilGrip from Momentive Performance Materials. TM Series, for example, SilGrip TM This includes PSA5080, PSA510, PSA518, PSA529, PSA590LD, PSA595, PSA610, PSA6573A, PSA6574, PSA810, PSA820, and PSA915.

[0071] The silicone pressure-sensitive adhesive compositions in this application preferably include a curing catalyst to improve performance such as cohesive strength, although in some embodiments the catalyst may not be used. The curing catalyst used in this application is not particularly limited and is usually selected according to the curing mechanism of the silicone pressure-sensitive adhesive. For example, if the silicone pressure-sensitive adhesive is cured by a radical reaction, the curing catalyst may include peroxides such as inorganic or organic peroxides. Examples of peroxides include, but are not limited to, aryl peroxides such as dibenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and combinations thereof. If the silicone pressure-sensitive adhesive is cured by a hydrosilylation reaction, the curing catalyst may include noble metal catalysts such as ruthenium, rhodium, palladium, osmium, iridium, and platinum, and combinations thereof. Examples of hydrosilylation catalysts include, but are not limited to, Ashby catalysts; Lamoreax catalysts; Karstedt catalysts; Modic catalysts; and Jeram catalysts and combinations thereof.

[0072] The curing catalyst may be present in an amount of up to about 10 parts by weight, preferably about 0.1 to about 8 parts by weight, and more preferably about 0.5 to about 5 parts by weight, per 100 parts by weight of polyorganosiloxane rubber.

[0073] While a suitable solvent may be included to adjust the viscosity of the silicone pressure-sensitive adhesive composition, solvent-free silicone pressure-sensitive adhesives are also applicable in this application. Examples of solvents include, but are not limited to, aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane and octane, and ketones such as isoparaffins, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and isobutyl acetate, and ethers such as diisopropyl ether and 1,4-dioxane, or combinations thereof. The amount of solvent typically depends on the viscosity of the rubber and the means by which the silicone pressure-sensitive adhesive composition is applied. In one example, a solvent contained in an amount of about 40% to about 70% by weight results in a solution with a viscosity suitable for coating. This solvent may be removed in a drying process at a relatively low temperature before curing the silicone PSA composition.

[0074] Examples of fillers, though not limited to those mentioned above, may include quartz powder, zinc oxide, aluminum hydroxide, titanium dioxide, light calcium carbonate, or combinations thereof, in order to increase cohesive strength and reduce cost. The amount of filler may vary over a wide range depending on the silicone PSA, the properties of the filler, and the intended application. For example, the filler may be present in an amount of 0 to about 150 parts by weight, preferably about 1 to about 100 parts by weight, per 100 parts by weight of polyorganosiloxane rubber.

[0075] Other optional components may include, for example, condensation accelerators to promote the condensation reaction of silanol groups, such as dibutyltin diacetate; non-reactive polyorganosiloxanes, such as polydimethylsiloxane resins and silsesquioxane resins; antioxidants, such as phenolic, quinoline, amine, phosphorus, phosphite, sulfur, and thioether antioxidants; light stabilizers, such as triazole and benzophenone light stabilizers; flame retardants, such as phosphate ester, halogen, phosphorus, and antimony flame retardants; and dyes and pigments.

[0076] Several optional additives are commercially available. Examples of commercially available additives include, but are not limited to, AnchorSil, which improves the adhesion of silicone PSA to substrates, particularly for polyester substrates. TM 2000, SilForce TM SL6020 or SilForce TM SS4300C, or SilQuest TM Adhesion promoters such as A-186 silane; and SilGrip TM It contains silicone resin additives to control tackiness, such as SR500 resin and SR545 resin, all of which are available from Momentive Performance Materials.

[0077] The silicone pressure-sensitive adhesive compositions described herein can have improved peel adhesion to low-energy surfaces such as silicones, fluoropolymers, and polyolefin materials. In one embodiment, the low-energy surface in this application may be silicone rubber. The adhesion to silicone rubber may be at least about 660 gf / inch, preferably about 700 gf / inch to about 1500 gf / inch, more preferably about 800 gf / inch to about 1400 gf / inch, and even more preferably about 1000 gf / inch to about 1300 gf / inch, when peeled at a 180° angle as determined by FINAT test method No. 1.

[0078] The silicone pressure-sensitive adhesive composition according to the present invention may be prepared by a process comprising mixing at least one boron-containing additive with polyorganosiloxane rubber and silicone resin, optionally with any of the optional components described above, such as a curing catalyst, solvent, filler, and other additives. This mixing may be carried out at room temperature or at a temperature not higher than 50°C, such as about 30°C to about 45°C, for a period of time, for example, several seconds to several hours, which is effective in obtaining a homogeneous mixture. If two or more boron-containing additives are used, they may be added together or individually. The components to be mixed may be added in any order. For example, in one embodiment, the boron-containing additive may be added together with or separately to a dispersion of polyorganosiloxane rubber and silicone resin, with or without a solvent; or the boron-containing additive may be mixed with the polyorganosiloxane rubber, and then the silicone resin and curing catalyst may be added thereto, with or without a solvent, simultaneously or sequentially. In a particular embodiment, the process for preparing the adhesive composition includes dispersing a polyorganosiloxane rubber and a silicone resin in a solvent, preferably an organic solvent such as toluene, xylene, heptane, or a combination thereof; and adding a boron-containing additive and a curing catalyst, optionally together with fillers or other additives, to the dispersion.

[0079] In another embodiment, the present invention provides an article such as a pressure-sensitive adhesive tape comprising the silicone pressure-sensitive adhesive composition described herein. This pressure-sensitive adhesive tape may be prepared by applying the silicone pressure-sensitive adhesive composition to a substrate such as a rigid substrate or a flexible substrate such as a polymer substrate. Examples of polymer substrates include, but are not limited to, polyester substrates such as polyethylene terephthalate or polybutylene terephthalate. The substrate may be used as is. Alternatively, the substrate may be pre-treated, for example, by corona; or with SilForce from Momentive Performance Materials. TM SS4191A and SilForceTM It may be coated with a primer such as SS6800.

[0080] The silicone pressure-sensitive adhesive compositions described herein have improved adhesion to low-energy surfaces such as silicone, fluoropolymers, and polyolefin materials. Therefore, pressure-sensitive adhesive tapes containing such compositions can be widely used for bonding materials having low-energy surfaces, particularly silicone materials. Thus, the present invention further relates to articles containing the silicone pressure-sensitive adhesive compositions described herein on low-energy surfaces such as silicone, fluoropolymers, and polyolefin materials, particularly on silicone rubber.

[0081] Examples The present invention will be described in more detail with reference to examples, but these examples should not be construed as limiting the scope of the invention. In the following description, “parts” and “%” mean “parts by weight” and “weight%” respectively, unless otherwise specified. Also, unless otherwise specified, all viscosities were measured at 25°C using a Brookfield rotational viscometer and reported in centipoise (cps).

[0082] Preparation Example 1: Synthesis of Dimethyldibutoxyboranylamine [ka] In a fume hood, tris(dimethylamino)borane (1.00 g, 0.007 mol, Sigma-Aldrich) and n-BuOH (1.04 g, 0.014 mol) were placed in a 25 ml flask at room temperature. Shaking generated gas, which was expelled from the flask. The reaction was continued for approximately one day until no more gas was expelled. A clear liquid was obtained and was usable.

[0083] Preparation Example 2: Synthesis of Dimethyldioxabololanylamine [ka] In a fume hood, tris(dimethylamino)borane (1.00 g, 0.007 mol, Sigma-Aldrich) and ethylene glycol (0.43 g, 0.007 mol) were placed in a 25 ml flask at room temperature. Shaking generated gas, which was expelled from the flask. The reaction was continued for approximately one day until no more gas was expelled. A white solid was obtained and was suitable for use.

[0084] Preparation Example 3: Synthesis of Tetraacetyl Diborate [ka] Acetic anhydride (24.4 g, 0.24 mol, Sinopharm) and boric acid (4.8 g, 0.08 mol, Sinopharm) were placed in a 100 ml three-necked flask equipped with a mechanical stirrer and a thermocouple. The temperature was gradually raised to 59°C using a hot water bath. After removing the hot water bath, the temperature spontaneously continued to rise from 59°C to 60.5°C over approximately 10 minutes. The temperature was then immediately lowered to 55°C using a cold water bath. The reaction stabilized at 59-60°C and was completed by refluxing for 1 hour.

[0085] The resulting product was cooled to 5°C, filtered under vacuum, and washed with 1:1 heptane / ethyl acetate. After drying in an oven at 40°C, the product was obtained in a yield of approximately 5 g.

[0086] The boron-containing compounds used in the following examples are listed in Table 1 below.

[0087] [Table 1] TIFF0007925120000014.tif233162

[0088] General procedure for preparing a silicone pressure-sensitive adhesive composition The amounts of boron-containing additive, 1.5 parts by weight of benzoyl peroxide, and 1.2 parts by weight of SR545 silicone resin additive (Momentive Performance Materials) shown in the following examples are mixed with 100 parts by weight (dry weight) of SilGrip, a toluene solution of silicone pressure-sensitive adhesive. TM A silicone pressure-sensitive adhesive composition was obtained by uniformly dispersing it in PSA610 (Momentive Performance Materials).

[0089] General procedure for preparing silicone pressure-sensitive adhesive tape A silicone pressure-sensitive adhesive composition with a solid content of 40% is used in SilForce TM A silicone pressure-sensitive adhesive tape was obtained by applying the adhesive to a 25 μm thin PET film pre-coated with SS4191A primer (Momentive Performance Materials), drying at 85°C for 2 minutes, and then curing at 170°C for 2 minutes. The thickness of the dried and cured adhesive composition on the tape was 25 μm.

[0090] Test method for peel adhesion strength (180 degrees) of silicone rubber The peel adhesion strength (180 degrees) was measured according to FINAT Test Method No. 1 at 50% relative humidity and a temperature of 25°C. A 25mm (1 inch) wide silicone pressure-sensitive adhesive tape was applied to vulcanized silicone rubber LSR2640 (Momentive Performance Materials), and then pressed once back and forth at a speed of 300 mm / min using a 2 kg roller. After 20 minutes and 72 hours, the tape was peeled off the silicone rubber at a 180-degree angle at a speed of 300 mm / min, and the peel adhesion strength was measured.

[0091] Examples 1 to 10 Silicone pressure-sensitive adhesive compositions were prepared using 6 parts by weight of each of the additives shown in Table 2 below. Silicone pressure-sensitive adhesive tapes were then prepared by coating the adhesive compositions onto a thin PET film using the general procedure described above. The tapes were tested for peel adhesion at 180 degrees at 20 minutes and 72 hours, respectively.

[0092] [Table 2]

[0093] From Table 2, it can be seen that compounds 2 to 6, individually, provide a silicone pressure-sensitive adhesive composition with significantly improved peel-off tackiness to silicone rubber compared to compound 1 under the same conditions.

[0094] Examples 11 to 19 Silicone pressure-sensitive adhesive compositions were prepared by combining 0.17 parts by weight of each of the additives shown in Table 3 below with 6 parts by weight of compound 1. Silicone pressure-sensitive adhesive tapes were then prepared by coating the adhesive compositions onto a thin PET film using the general procedure described above. The tapes were then tested for peel adhesion at 180 degrees at 20 minutes and 72 hours, respectively.

[0095] [Table 3]

[0096] Tables 2 and 3 show that compounds 2, 7, 8, and 9, when combined with compound 1, achieved synergistic effects, as each of these combinations resulted in a silicone pressure-sensitive adhesive composition with higher peel tack to silicone rubber than the corresponding adhesive strength obtained when each compound is used alone. Combinations of compounds 2, 8, and 9 with compound 1 achieved even higher unexpected peel tack to silicone rubber, exceeding 1000 gf / inch. In terms of appearance, the silicone pressure-sensitive adhesive composition using compound 2 was transparent when combined with compound 1. Compounds 7, 8, and 9 were less transparent when used with compound 1 compared to compound 2, which is likely due to their polarity.

[0097] Example 20 The silicone pressure-sensitive adhesive compositions prepared in Example 11 were aged for 8 weeks at room temperature and 40°C, respectively. The changes in viscosity and appearance of the adhesive compositions over time are shown in Table 4 below.

[0098] Silicone pressure-sensitive adhesive compositions were aged for 8 weeks and then coated onto thin PET films using the general procedure described above to prepare silicone pressure-sensitive adhesive tapes. These tapes were then tested for peel adhesion to silicone rubber at 180°C at 20 minutes, 24 hours, and 72 hours, respectively. The peel adhesion results of the aged adhesive compositions are shown in Figure 1 in comparison to newly prepared adhesive compositions that were not aged. In Figure 1, in each of the three sets of three bars, the left bar represents a new sample without aging, the middle bar represents a sample aged at room temperature, and the right bar represents a sample aged at 40°C.

[0099] [Table 4]

[0100] As can be seen from Table 4, the viscosity and appearance of the composition remained substantially unchanged over time, both at room temperature and after heating to 40°C.

[0101] Furthermore, as can be seen from Figure 1, the peel-off adhesive strength to silicone rubber obtained from newly prepared samples without aging and samples aged at different temperatures (room temperature and a 40°C increase) was substantially the same.

[0102] All of the results described above demonstrate that the silicone pressure-sensitive adhesive composition of the present invention exhibited excellent stability at both room temperature and high storage temperatures.

[0103] Examples 21 to 26 As shown in Table 5, silicone pressure-sensitive adhesive compositions were prepared by combining compound 2 with compound 1 in various amounts. Using the general procedure described above, these adhesive compositions were coated onto a thin PET film to prepare silicone pressure-sensitive adhesive tapes. These tapes were then tested for peel adhesion at 180 degrees at 20 minutes and 72 hours, respectively. The results are shown in Table 5 and Figure 2.

[0104] [Table 5]

[0105] Surprisingly, as shown in Table 5 and Figure 2, the improvement in peel adhesion to silicone rubber brought about by compound 2 was found not to be proportional to the amount added. The maximum improvement in peel adhesion brought about by compound 2 was achieved at a very small weight ratio level of approximately 1:35 (compound 2:compound 1). Such technical effects are advantageous for further reducing the amount of additive added in order to achieve the desired peel adhesion to low-energy surfaces.

[0106] Example 27 Each of the silicone pressure-sensitive adhesive tapes prepared according to the reference example and Example 23 was bonded to a fluoropolymer release film FL132 (Housewell) to form a laminate. Next, this laminate was aged at room temperature and 40°C, respectively, and then the peel force (180°) against the release liner FL132 was tested weekly at room temperature according to FINAT test method No. 3 (slow peel force) using the procedure described above.

[0107] The laminate was fixed with double-sided adhesive across the entire test area of ​​the laminate and pressed once back and forth using a 2 kg roller at a speed of 300 mm / min. The laminate was then pulled apart at a 180-degree angle at a speed of 300 mm / min, and the peeling force required to separate the release film from the pressure-sensitive adhesive tape was measured.

[0108] The measured peel force results are shown in Figure 3 (room temperature) and Figure 4 (temperature 40°C). These results indicate that the silicone pressure-sensitive adhesive composition of the present invention has a more appropriate peel force than conventional release films, and that its peel force remains substantially stable over time at room temperature and when the temperature is raised to 40°C.

[0109] While this disclosure has been described in relation to preferred embodiments, it will be understood by those skilled in the art that various modifications may be made without departing from the scope of the disclosure, and that elements may be replaced with equivalents. In addition, many modifications may be made to the disclosed teachings without departing from the essential scope of the disclosure in order to adapt to particular circumstances or materials. Thus, this disclosure is not intended to limit to any particular embodiment disclosed as the best form for carrying out this disclosure, but rather is intended to encompass all embodiments included in the appended claims.

Claims

1. A silicone pressure-sensitive adhesive composition, which includes: A boron-containing additive comprising at least one cyclic borate compound, and i) Boric acid; and ii) Acyclic borate compounds A silicone pressure-sensitive adhesive composition comprising at least one element selected from the group consisting of the following.

2. At least one boron-containing additive comprises a cyclic borate compound and an acyclic borate compound in combination with at least one of a boron-containing compound, a cyclic borate compound, or boric acid, wherein the boron-containing compound comprises a boroxine compound and a borane compound containing a boron-nitrogen covalent bond. A silicone pressure-sensitive adhesive composition according to claim 1, selected from the group consisting of the following.

3. The boroxine compound is of general formula (I): 【Chemistry 1】 wherein R １ , R ２ and R ３ are each independently a hydrogen atom; a hydroxyl group; or a monovalent group having up to 30 carbon atoms selected from the group consisting of an alkyl group, an alkoxy group, hydroxyalkyl and alkoxyalkyl, or -R ８ -N(R ９ )(R １０ ), wherein R ８ is a direct bond or a divalent linking group, and R ９ and R １０ are each independently a hydrogen atom, alkyl, hydroxyalkyl or alkoxyalkyl, the silicone pressure-sensitive adhesive composition according to claim 2.

4. In the formula R １ , R ２ and R ３ Each of these is independently a monovalent group having up to 20 carbon atoms selected from the group consisting of alkoxy groups and alkoxyalkyl groups, or -R ８ -N(R) ９ ) (Caution １０ ) and in the formula R ８ R is a direct bond, an alkylene group or an oxyalkylene group, and ９ and R １０ The silicone pressure-sensitive adhesive composition according to claim 3, wherein each of the elements is independently a hydrogen atom, an alkyl group, or an alkoxyalkyl group.

5. Boroxine compounds have general formula (I-1) or general formula (I-2): 【Chemistry 2】 In the formula R １１ , R １２ and R １３ Each is independently selected from the group consisting of alkyl groups, and is a monovalent group having up to 20 carbon atoms, or -R １４ -N(R) １５ ) (Caution １６ ) and in the formula R １４ is an alkylene group, and R １５ and R １６ Each is independently a hydrogen atom, an alkyl group, or an alkoxyalkyl group; 【Transformation 3】 In the formula R １７ A silicone pressure-sensitive adhesive composition according to any one of claims 2 to 4, wherein each of them is independently an alkyl or alkoxyalkyl group having up to 20 carbon atoms, or a hydrogen atom.

6. Borane compounds containing a boron-nitrogen covalent bond have general formula (II): 【Chemistry 4】 In the formula R ４ and R ５ Each is independently a monovalent group having up to 30 carbon atoms selected from the group consisting of alkyl groups, alkoxy groups, hydroxyalkyl groups, and alkoxyalkyl groups, or -R ８ -N(R) ９ ) (Caution １０ ) and in the formula R ８ is a direct bond or a divalent linking group, and R ９ and R １０ Each of these is independently a hydrogen atom, an alkyl group, a hydroxyalkyl group, or an alkoxyalkyl group; R ４ and R ５ They may together form a ring, which includes an alkylene group having up to 10 carbon atoms bonded to the B atom of formula (II) via an oxygen atom; and R ６ and R ７ The silicone pressure-sensitive adhesive composition according to claim 2, wherein each of them is independently an alkyl, hydroxyalkyl, or alkoxyalkyl group having up to 30 carbon atoms, or a hydrogen atom.

7. Borane compounds containing a boron-nitrogen covalent bond have the general formula (II-1): 【Transformation 5】 In the formula R ２１ , R ２２ , R ２３ , R ２４ , R ２５ and R ２６ The silicone pressure-sensitive adhesive composition according to claim 6, wherein each is independently an alkyl, hydroxyalkyl, or alkoxyalkyl, and each independently has up to 20 carbon atoms or is a hydrogen atom.

8. Borane compounds containing a boron-nitrogen covalent bond have the general formula (II-2): 【Transformation 6】 In the formula R ２７ and R ２８ Each is a monovalent group having up to 20 carbon atoms independently selected from alkyl groups, or -R ３１ -N(R) ３２ ) (Caution ３３ ) and in the formula R ３１ is an alkylene group, and R ３２ and R ３３ Each of these is independently a hydrogen atom, an alkyl group, or an alkoxyalkyl group; R ２７ and R ２８ They may together form a ring, which comprises one to six carbon atom alkylene groups bonded to the O atom of formula (II-2); and in formula R ２９ and R ３０ The silicone pressure-sensitive adhesive composition according to claim 6, wherein each is independently an alkyl, hydroxyalkyl, or alkoxyalkyl, and each independently has up to 20 carbon atoms or is a hydrogen atom.

9. In the formula R ２７ and R ２８ Together they form a ring, and bonded to the O atom in formula (II-2) is -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -ien-CH ２ CH (CH ３ )-,-CH(CH ３ )CH(CH ３ ) -, -CH ２ CH (CH ３ )CH ２ -, or -CH ２ C (CH ３ ) ２ CH ２ A silicone pressure-sensitive adhesive composition according to claim 8, comprising -

10. The silicone pressure-sensitive adhesive composition according to claim 2, wherein the acyclic borate compound is present in an amount of about 50% to about 99% by weight relative to the total weight of at least one boron-containing additive.

11. A silicone pressure-sensitive adhesive composition according to any one of claims 1 to 10, wherein at least one boron-containing additive comprises an acyclic borate compound in combination with a boroxine-based compound having the general formula (I) as defined in claim 3 or 4.

12. The silicone pressure-sensitive adhesive composition according to claim 11, wherein the weight ratio of the boroxine compound to the acyclic borate compound is about 1:100 to about 1:

1.

13. At least one boron-containing additive comprises an acyclic borate compound in combination with a cyclic boronate compound having general formula (III): 【Transformation 7】 In the formula R ３４ and R ３５ Each is independently an alkyl having 1 to 6 carbon atoms or an aryl having 6 to 12 carbon atoms, R ３４ and R ３５ They may form a ring together, and this ring is of the formula -O-L ３ -CH ２ It contains a divalent group, where -L ３ - The group is bonded to the B atom of formula (III) via an oxygen atom; L １ , L ２ and L ３ are each independently a divalent group of formula -[C(O)] ｍ C ｎ H ２ｎ -, wherein m is 0 or 1, and n is an integer of 0 to 4, provided that when R ３４ and R ３５ together form a ring, m defined for at least one of L １ , L ２ and L ３ is 0. The silicone pressure-sensitive adhesive composition according to any one of claims 1 to 10.

14. Polyorganosiloxane rubber; and Formula M = R ３ SiO １／２ at least one M unit of the formula, T = RSiO ３／２ T unit of the formula and Q = SiO ４／２ at least one unit selected from the group consisting of Q units of the formula, and optionally D = R ２ SiO ２／２ a silicone resin comprising at least one D unit of the formula, wherein each R is independently a monovalent hydrocarbon group having 1 to 6 carbon atoms; and Selective curing catalyst A silicone pressure-sensitive adhesive composition according to any one of claims 1 to 13, further comprising:

15. A silicone pressure-sensitive adhesive composition according to any one of claims 1 to 14, wherein the composition is cured by a radical reaction or a hydrosilylation reaction.

16. An article comprising a silicone pressure-sensitive adhesive composition according to any one of claims 1 to 15.

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