Silicone and filler compositions with high flow

Abstract

An organosilicon and filler composition is provided comprising: (A) an organopolysiloxane; (B) a filler; and (C) a filler treating agent represented by the following general formula (I): MD x U y M’ (I). Also provided are methods for treating fillers, use of the filler treating agent (C) in treating fillers, and encapsulants, sealants, conformal coatings, and / or thermal interface materials obtained from the organosilicon and filler composition.

Description

Technical Field

[0001] This invention relates to organosilicon and filler compositions with high fluidity. The invention also relates to methods for treating fillers, the use of side-branched epoxy-functionalized siloxanes in treating fillers, and encapsulants, sealants, conformal coatings, and / or thermal interface materials obtained from said organosilicon and filler compositions. Background Technology

[0002] Functional fillers impart a variety of characteristic advantages to silicone compositions, including higher modulus, thermal conductivity, electrical conductivity, specific rheological behavior, and even lower cost. Therefore, they are widely used in silicone compositions where such properties are particularly desirable.

[0003] However, adding fillers typically reduces the flowability of silicone compositions. In some applications, such as encapsulants, sealants, conformal coatings, and thermal interface materials (TIMs), even higher flowability requirements exist, where filler treatment is crucial for maintaining good flowability to meet these ultra-flowability demands.

[0004] For filler treatment, various alkoxy-based silanes or polymers are well known in the art as filler treatment agents. They have proven to be very effective in most cases. In particular, the value of polymer-based filler treatment agents in both low- and high-fill systems has been well demonstrated. However, most alkoxy-based polymer filler treatment agents are expensive, and their ability to promote flowability is sometimes limited for applications with ultra-fluidity requirements. Furthermore, considering sustainability, alkoxy-based filler treatment technologies ultimately release alcohol byproducts (most often methanol), which contradicts global initiatives for sustainability.

[0005] On the other hand, epoxy siloxanes for metal treatment are also well known in the art. For example, Patent Document 1 discloses a two-component anti-corrosion pigment comprising a metal filler and also including an epoxy siloxane. Additionally, Patent Document 2 discloses a method for metal treatment using a component comprising an epoxy siloxane. In both of these prior art, the epoxy siloxane is cured into a network to achieve the desired anti-corrosion effect or metal treatment effect.

[0006] However, in patent documents 1 and 2, since the epoxysiloxane is not used as a filler agent but rather solidifies into a network, it exhibits gel-like properties rather than fluidity. Therefore, the epoxysiloxane used therein cannot meet the requirements for ultra-fluidity.

[0007] In addition, aminosiloxanes and hydroxyl-containing siloxanes can also be used as filler treatment agents, such as in Patent Document 3, which utilizes functional siloxanes having hydroxyl and amino groups. However, their flowability-enhancing effect is rather limited, especially in highly filled systems. Furthermore, amino and hydroxyl groups often interfere with the curing reactions of organosilicon compositions, such as hydrosilylation.

[0008] [Existing technical documents]

[0009] Patent Document 1: US Patent Publication No. CN101198661A

[0010] Patent Document 2: US Patent Publication No. CN109321911A

[0011] Patent Document 3: Canadian Patent Publication No. CA2270005A1 Summary of the Invention

[0012] The problem to be solved by the present invention

[0013] In the field of organosilicon composition technology, filler treatment agents that can greatly enhance flowability to meet ultra-flowability requirements are not well known. Regarding the use of epoxysiloxanes in filler-containing systems, only a few prior art materials (such as Patent Documents 1 and 2) provide some disclosure, but the epoxysiloxanes used in those scenarios are cured into a network and therefore do not promote flowability.

[0014] Therefore, in view of the above-mentioned problems in the prior art, the object of the present invention is to provide an organosilicon and filler composition with high fluidity. In particular, the object of the present invention is to provide an organosilicon and filler composition comprising a novel filler treatment agent and thereby exhibiting high fluidity.

[0015] Furthermore, another object of the present invention is to provide a method for treating fillers, the use of the novel filler treatment agent in treating fillers, and encapsulants, sealants, conformal coatings, and / or thermal interface materials obtained from the organosilicon and filler composition.

[0016] Methods for solving problems

[0017] As a result of ongoing research, the inventors have discovered a novel filler treatment technique using side-linked epoxy-functionalized siloxanes. The side-linked epoxy-functionalized siloxanes used in this filler treatment technique (preferably falling within a suitable epoxy equivalent range) serve as filler treatment agents to promote flowability. The method of this filler treatment technique involves mixing followed by heating under vacuum. This invention is a product of this discovery.

[0018] One aspect of the present invention is a composition comprising the following organosilicon and filler:

[0019] (A) Organopolysiloxane;

[0020] (B) Packing material; and

[0021] (C) Filler treatment agents of side-chain epoxy-modified organosiloxanes represented by the following general formula (I):

[0022]

[0023] Where D represents R2SiO 2 / 2 Unit, wherein R is the same or different monovalent alkyl group without epoxy functional group each time it appears; U indicates the presence of R' n R (2-n) SiO 2 / 2 The unit has an epoxy group, wherein R is a monovalent alkyl group, and R' is a monovalent organic group containing at least one ortho-epoxy group, and n has a value of 1 to 2; M and M' each time they appear have the formula R3SiO 1 / 2 The same or different end-capping units, wherein R is the same or different monovalent alkyl group without an epoxy group each time it appears; x is an integer having a value from 10 to 1,000, and y is an integer having a value from 1 to 100.

[0024] In some embodiments, the filler treatment agent (C) has an epoxy equivalent of more than 350 g / mol, preferably more than 1,000 g / mol, more preferably more than 2,000 g / mol, and most preferably more than 3,000 g / mol.

[0025] In some embodiments, R' is the same or different monovalent alkyl group each time it appears, independently having a main chain containing 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 2 to 12 carbon atoms, even more preferably 2 to 10 carbon atoms, even more preferably 3 to 8 carbon atoms, and even more preferably 4 to 5 carbon atoms. In some embodiments, the main chain of R' independently has one or two oxygen atoms between two adjacent carbon atoms.

[0026] In some embodiments, the epoxy functional group is located at the end of R' and is independently attached to the end of R' via a direct bond or a linker. In some embodiments, the linker is selected from the group consisting of ether groups, ester groups, carbonyl groups, and urethane groups.

[0027] In some preferred embodiments, the filler treatment agent (C) is represented by the following general formula:

[0028]

[0029] where R1, R2 and R3 independently represent side group groups having an epoxy functional group, (n + m) ≥ 1, and p ≥ 10.

[0030] In some embodiments, based on the total weight of the composition, the amount of the filler treatment agent (C) is 0.1% to 10% by weight, preferably 0.2% to 5% by weight, more preferably 0.3% to 3% by weight, further more preferably 0.4% to 2% by weight, further more preferably 0.5% to 1.5% by weight, and most preferably 0.8% to 1.2% by weight.

[0031] In some embodiments, the filler (B) is an inorganic filler, preferably one or more selected from the group consisting of a heat conductive filler, a conductive filler, or a reinforcing filler, and more preferably contains a reinforcing filler, especially when the silicone and filler composition of the present invention is used in applications of encapsulants or sealants.

[0032] In some embodiments, based on the total weight of the composition, the amount of the filler (B) is 1% to 95% by weight, preferably 5% to 90% by weight, more preferably 10% to 90% by weight, further more preferably 20% to 85% by weight, and further more preferably 30% to 80% by weight.

[0033] In some embodiments, the organopolysiloxane (A) has a linear, branched, partially branched, cyclic, resinous (i.e., having a three-dimensional network), dendritic structure, or a combination of different structures. In some embodiments, the organopolysiloxane (A) contains any combination of M siloxy units, D siloxy units, T siloxy units, and / or Q siloxy units, where the M siloxy unit is represented by R3SiO 1 / 2 is represented by, the D siloxy unit is represented by R2SiO 2 / 2 is represented by, the T siloxy unit is represented by RSiO 3 / 2 is represented by, and the Q siloxy unit is represented by SiO 4 / 2 is represented by, where R is an independently selected substituent.

[0034] In some embodiments, the organopolysiloxane (A) has the following average unit formula (II):

[0035] ;

[0036] where each R is an independently selected substituent; 0 < a ≤ 0.99; 0 < b ≤ 0.99; 0 ≤ c ≤ 0.2; and 0 ≤ d ≤ 0.2, provided that a + b + c + d = 1.

[0037] In some embodiments, the organopolysiloxane (A) is an organopolysiloxane having at least two alkenyl groups having 2 to 12 carbon atoms per molecule.

[0038] In some embodiments, the organopolysiloxane (A) has a viscosity of at least 10 mPa•s at 25°C, such as 10 mPa•s to 100,000 mPa•s, preferably 20 mPa•s to 50,000 mPa•s, more preferably 50 mPa•s to 10,000 mPa•s, and even more preferably 50 mPa•s to 5,000 mPa•s.

[0039] In some embodiments, the amount of the organopolysiloxane (A) is from 1 wt% to 80 wt%, preferably from 5 wt% to 70 wt%, more preferably from 10 wt% to 60 wt%, and most preferably from 20 wt% to 50 wt%, based on the total weight of the composition.

[0040] A second aspect of the invention is a method for treating fillers, the method comprising the steps of mixing fillers (B) with a filler treatment agent (C) described in the first aspect, and then heating them under vacuum.

[0041] In some embodiments, the filler (B) and filler treatment agent (C) are mixed and heated under vacuum in the presence of the organopolysiloxane (A) described in the first aspect. In some other embodiments, the filler (B) and filler treatment agent (C) are mixed and heated under vacuum in the absence of the organopolysiloxane (A) described in the first aspect.

[0042] In some embodiments, the filler (B) and the filler treatment agent (C) are heated under vacuum at 100°C to 150°C, preferably 110°C to 140°C, more preferably 120°C to 130°C for 30 to 120 minutes, preferably 45 to 90 minutes, more preferably 60 to 70 minutes.

[0043] The compositions of the present invention may also contain or not contain chemical formula R f Si(OR g )3 alkyltrialkoxysilane (component D), wherein R f Each time it appears, it is independently an alkyl group having 1 to 12 carbon atoms; and R g Each time it appears, it is independently an alkyl group having 1 to 6 carbon atoms. R gIdeally, it is methyl to form a methoxy group attached to a silicon atom. Particularly desirable alkyltrialkoxysilanes are methyltrimethoxysilane, n-decyltrimethoxysilane, n-octyltrimethoxysilane, or mixtures thereof. Component (D) can be used to prevent filler sedimentation and extend the service life of the composition. Based on the weight of component (A), it can be present in amounts from 0% to 5% by weight, and can be 0% or more by weight, 0.05% or more by weight, 0.08% or more by weight, 0.10% or more by weight, 0.15% or more by weight, or even 0.2% or more by weight, while typically 5% or less by weight, and can be 4.0% or less by weight, 3.0% or less by weight, 2.0% or less by weight, 1.0% or less by weight, 0.5% or less by weight, or even 0.2% or less by weight.

[0044] The compositions of the present invention may also contain or exclude organopolysiloxanes (“crosslinking agents”, component (E)) having at least two or at least three silicon-bonded hydrogen atoms per molecule and excluding alkenyl groups. Typically, based on the weight of component (A), the amount of polyorganohydrosiloxane in the composition may be from 0.1 wt% to 20 wt%, and may be 0.1 wt% or more, 0.5 wt% or more, 1.0 wt% or more, 2.0 wt% or more, 3.0 wt% or more, 4.0 wt% or more, 5 wt% or more, or even 7 wt% or more, while typically 20.0 wt% or less, and may be 18.0 wt% or less, 16.0 wt% or less, 15.0 wt% or less, 12.0 wt% or less, 10.0 wt% or less, or even 8.0 wt% or less.

[0045] The compositions of the present invention may also contain or exclude a hydrosilylation catalyst (component (F)). Hydrosilylation catalysts are known in the art and are commercially available. Hydrosilylation catalysts include platinum (Pt) group metal catalysts. Based on the weight of component (A), the amount of catalyst is sufficient to provide from 1 ppm to 1000 ppm of platinum group metals, and may be 1 ppm or more, 5 ppm or more, 10 ppm or more, 20 ppm or more, or even 30 ppm or more, while typically 1,000 ppm or less, and may be 500 ppm or less, 300 ppm or less, 130 ppm or less, or even 100 ppm or less.

[0046] The third aspect of the invention is the use of the filler treatment agent (C) described in the first aspect in the treatment of fillers.

[0047] The fourth aspect of the invention is an encapsulant obtained from the organosilicon and filler composition described in the first aspect.

[0048] The fifth aspect of the invention is a sealant obtained from the organosilicon and filler composition described in the first aspect.

[0049] The sixth aspect of the invention is a conformal coating obtained from the organosilicon and filler composition described in the first aspect.

[0050] The seventh aspect of the present invention is a thermal interface material obtained from the organosilicon and filler composition described in the first aspect.

[0051] Effects of the present invention

[0052] This invention provides organosilicon and filler compositions with very high flowability. In particular, according to this invention, by adding the filler treatment agent (C) (which is a side-linked epoxy-functionalized siloxane) to a filler-filled organosilicon formulation in the same weight percentage, the filler treatment agent (C) of this invention will be comparable to or even better than conventional alkoxy-based filler treatment agents in promoting flowability.

[0053] Furthermore, unlike conventional filler treatment agents, the epoxy functional groups in the filler treatment agent (C) of the present invention do not generate alcohols during the filler treatment process, which is highly advantageous in terms of sustainability. Moreover, the filler treatment agent (C) of the present invention is a side-linked epoxy-functionalized siloxane, which can be easily prepared at low cost through equilibration followed by hydrosilylation. Therefore, it is generally more cost-effective than conventional alkoxy-based polymer filler treatment agents. Detailed Implementation

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. As disclosed herein, “and / or” means “and, or as an alternative” or “additionally or alternatively”. Unless otherwise specified, all scopes include the endpoints.

[0055] As used herein, the term “polymer” or “polymerization” in alternative contexts refers to a polymer prepared from one or more different monomers, such as copolymers, terpolymers, quaternary copolymers, pentomers, etc., and can be any of random polymers, block polymers, graft polymers, sequence polymers, or gradient polymers.

[0056] In this invention, unless otherwise stated, the singular forms of the articles “a” and “the / said” include plural references. In this invention, the terms “comprising,” “containing,” “including,” and variations thereof are open-ended claim language, i.e., allowing for additional elements. In this invention, the use of “for example,” “eg,” “such as,” and “including” to list illustrative examples does not imply limitation to the listed examples. Therefore, “for example” or “such as” means “for example, but not limited to” or “such as, but not limited to” and covers other similar or equivalent examples.

[0057] As used herein, the term "about" is used to reasonably encompass or describe minute variations in numerical values ​​measured by instrumental analysis or as a result of sample handling. Such minute variations can be approximately ±0% to 25%, ±0% to 10%, ±0% to 5%, or ±0% to 2.5% of the numerical value. Furthermore, the term "about" applies to two numerical values ​​when associated with a range of values. Additionally, the term "about" applies to numerical values ​​even when not explicitly stated otherwise.

[0058] It should be understood that the appended claims are not limited to the specific and particular compounds, compositions, or methods described in the detailed embodiments, which may vary among specific embodiments falling within the scope of the appended claims. With regard to any Markush group relied upon herein for describing specific features or aspects of various embodiments, it should be understood that different, specific, and / or unexpected results can be obtained from each member of the corresponding Markush group, independent of all other Markush members. Each member of the Markush group may be relied upon individually and / or in combination and provides sufficient support for specific embodiments within the scope of the appended claims.

[0059] It should also be understood that any scopes and subscopes relied upon in describing the various embodiments of the invention fall independently and collectively within the scope of the appended claims, and should be understood as describing and contemplating all scopes including integer and / or fractional values ​​therein, even if such values ​​are not explicitly stated herein. Those skilled in the art will readily recognize that the enumerated scopes and subscopes adequately describe and enable the various embodiments of the invention, and that such scopes and subscopes may be further described as related halves, thirds, quarters, fifths, etc. By way of example only, the scope of “0.1 to 0.9” may be further described as the lower third (i.e., 0.1 to 0.3), the middle third (i.e., 0.4 to 0.6), and the upper third (i.e., 0.7 to 0.9), which are individually and collectively within the scope of the appended claims, and may be individually and / or collectively relied upon and provide sufficient support for specific embodiments within the scope of the appended claims. Furthermore, with regard to limiting or modifying language such as “at least,” “greater than,” “less than,” and “not exceeding,” it should be understood that such language includes subscopes and / or upper or lower limits. As another example, the scope of "at least 10" essentially includes sub-scopes of at least 10 to 35, at least 10 to 25, 25 to 35, etc., and each sub-scope can be relied upon individually and / or collectively to provide sufficient support for specific embodiments within the scope of the appended claims. Finally, independent numbers within the disclosed scope can be relied upon to provide sufficient support for specific embodiments within the scope of the appended claims. For example, the scope of "1 to 9" includes individual integers such as 3, and individual numbers including decimal points (or fractions) such as 4.1, which can be relied upon to provide sufficient support for specific embodiments within the scope of the appended claims.

[0060] In this invention, a silicone and filler composition with very high flowability is provided. Here, the term "high flowability" has the same meaning as commonly understood by those skilled in the art, and in particular, in this invention, it preferably means high enough flowability to allow 1 mL of material to flow into a circle with a diameter of about 100 mm on a pre-cleaned glass plate in about 60 minutes.

[0061] Specifically, the organosilicon and filler composition of the present invention comprises, is substantially composed of, or is composed of: (A) an organopolysiloxane; (B) a filler; (C) a filler treatment agent represented by the following general formula (I):

[0062]

[0063] Where D represents R2SiO 2 / 2Unit, wherein R is the same or different monovalent alkyl group without epoxy functional group each time it appears; U indicates the presence of R' n R (2-n) SiO 2 / 2 The unit has an epoxy group, wherein R is a monovalent alkyl group, and R' is a monovalent organic group containing at least one ortho-epoxy group, and n has a value of 1 to 2; M and M' each time they appear have the formula R3SiO 1 / 2 The same or different end-capping units, wherein R is the same or different monovalent alkyl group without an epoxy group each time it appears; x is an integer having a value from 10 to 1,000, and y is an integer having a value from 1 to 100.

[0064] Component (A)

[0065] In this invention, component (A) is well known in the art, particularly in the fields of encapsulants, sealants, conformal coatings, and thermal interface materials. While the molecular structure of component (A) is not particularly limited, examples include linear, branched, partially branched, cyclic, resinous (i.e., structures with a three-dimensional network), and dendritic structures. Component (A) can also be a mixture comprising combinations of two or more of these molecular structures. For example, component (A) may comprise any combination of M-siloxy units, D-siloxy units, T-siloxy units, and / or Q-siloxy units, and these siloxy units can be combined in various ways to form linear, branched, cyclic, resinous (three-dimensional network), and / or dendritic structures.

[0066] When component (A) comprises T-siloxane units and / or Q-siloxane units, component (A) is branched or resinous. When component (A) is branched or resinous, component (A) is typically a copolymer comprising a combination of T-siloxane units and / or Q-siloxane units with M-siloxane units and / or D-siloxane units. For example, component (A) may be DT resin, MT resin, MDT resin, DTQ resin, MTQ resin, MDTQ resin, DQ resin, MQ resin, DTQ resin, MTQ resin, or MDQ resin. Alternatively, in some embodiments, component (A) is linear, in which case it comprises D-siloxane units and M-siloxane units.

[0067] In some embodiments, the organopolysiloxane (A) preferably has the following average unit formula (II):

[0068] ;

[0069] Each R is an independently selected substituent; 0 < a ≤ 0.99; 0 < b ≤ 0.99; 0 ≤ c ≤ 0.2; and 0 ≤ d ≤ 0.2, provided that a + b + c + d = 1.

[0070] Each substituent as the group R can independently be, but is not limited to, a linear, branched or cyclic monovalent hydrocarbon group, or any kind of functional group commonly used in the art. Here, examples of the linear or branched monovalent hydrocarbon group can be: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl or similar alkyl groups; and 3-chloropropyl group, 3,3,3-trifluoropropyl group, or similar haloalkyl groups. Examples of the cyclic monovalent hydrocarbon group can be: phenyl, tolyl, xylyl, naphthyl or similar aryl groups; benzyl, phenethyl or similar aralkyl groups.

[0071] In certain embodiments, the group R may further include some unsaturated monovalent hydrocarbon groups, such as alkenyl groups. In other words, component (A) can be an organopolysiloxane having at least two alkenyl groups with 2 to 12 carbon atoms per molecule. Examples of the alkenyl group are vinyl group, allyl group, butenyl group, pentenyl group and hexenyl group, but from the perspective of economic efficiency and reactivity, the vinyl group is preferred.

[0072] In addition, although not particularly limited thereto, the viscosity of component (A) at 25 °C is at least 10 mPa•s, such as 10 mPa•s to 100,000 mPa•s, preferably 20 mPa•s to 50,000 mPa•s, more preferably 50 mPa•s to 10,000 mPa•s, even more preferably 50 mPa•s to 5,000 mPa•s. This is because if the viscosity at 25 °C is not lower than the lower limit of the above range, the oil bleeding of the composition will be acceptable, and when the composition further includes components (E) and (F) to form a curable composition, the physical properties of the obtained cured product, especially flexibility and elongation, can be significantly increased; in contrast, if the viscosity does not exceed the upper limit of the above range, the operability (such as fluidity, printability, extrusion rate, etc.) of the obtained composition can be increased. The viscosity is measured by using a rotational viscometer according to ASTM D 1084.

[0073] Furthermore, although not particularly limited thereto, the amount of component (A) is from 1% to 80% by weight, preferably from 5% to 70% by weight, more preferably from 10% to 60% by weight, and most preferably from 20% to 50% by weight, based on the total weight of the composition. This is because if the amount of component (A) falls within the above range, the desired properties such as thermal conductivity will be achieved, and when the composition also includes components (E) and (F) to form a curable composition, it is sufficient to form the desired cured product.

[0074] Examples of organopolysiloxanes in component (A) include dimethylpolysiloxanes with both ends of the molecular chain capped with trimethylsiloxy groups, methylphenylpolysiloxanes with both ends of the molecular chain capped with trimethylsiloxy groups, copolymers of dimethylsiloxanes and methylvinylsiloxanes with both ends of the molecular chain capped with trimethylsiloxy groups, dimethylsiloxanes, methylvinylsiloxanes and methylphenylsiloxanes with both ends of the molecular chain capped with trimethylsiloxy groups, and dimethylvinylsiloxanes with both ends of the molecular chain capped with trimethylsiloxy groups. The copolymers of dimethyl polysiloxanes with dimethyl vinyl siloxane groups at both ends of the molecular chain, methyl phenyl polysiloxanes with dimethyl vinyl siloxane groups at both ends of the molecular chain, and methyl vinyl siloxanes, and dimethyl polysiloxanes with dimethyl vinyl siloxane groups at both ends of the molecular chain.

[0075] Component (B)

[0076] In this invention, component (B) is used to impart various characteristic advantages to the organosilicon composition containing component (A), including higher modulus, thermal conductivity, electrical conductivity, and specific rheological behavior. It is preferably an inorganic filler, more preferably one or more selected from the group consisting of thermally conductive fillers, electrically conductive fillers, or reinforcing fillers, and more preferably contains reinforcing fillers, particularly when the organosilicon and filler composition of this invention is used in encapsulant or sealant applications.

[0077] Reinforcing fillers are components that impart mechanical strength to the cured product obtained by curing the compositions of the present invention and improve its performance as a protective agent or adhesive. Exemplary reinforcing fillers may include, for example, inorganic fillers such as pyrolytic silica fine powder, precipitated silica fine powder, combusted silica fine powder, pyrolytic titanium dioxide fine powder, quartz fine powder, calcium carbonate fine powder, diatomaceous earth fine powder, alumina fine powder, aluminum hydroxide fine powder, zinc oxide fine powder, and zinc carbonate fine powder, wherein these inorganic fillers may include an inorganic filler surface treated with a treatment agent including organoalkoxysilanes such as methyltrimethoxysilane, organohalosilanes such as trimethylchlorosilane, organosilazanes such as hexamethyldisilazane, and siloxane oligomers such as dimethylsiloxane oligomers capped with α,ω-silanol groups, methylphenylsiloxane oligomers capped with α,ω-silanol groups, and methylvinylsiloxane oligomers capped with α,ω-silanol groups. Specifically, by pretreating the surface of component (B) with a low-polymerization degree organopolysiloxane (suitably, a dimethyl polysiloxane with α,ω-silanol groups at the ends of the molecular chain) having silanol groups at both ends of the molecular chain, excellent initial adhesion, adhesion durability and adhesion strength at room temperature can be achieved, and further, sufficient usability (shelf life, treatment operation time and storage life) can be ensured.

[0078] While not particularly limited to this, based on laser diffraction / scattering particle size distribution measurements, the particle size of the fine powder used to reinforce the filler can range from, for example, 0.01 μm to 1000 μm at the median diameter.

[0079] Thermally conductive or electrically conductive fillers are components that impart thermal or electrical conductivity to the compositions of the present invention as desired. Examples include: fine metal powders, such as gold, silver, nickel, and copper; fine powders obtained by depositing or electroplating metals (such as gold, silver, nickel, or copper) onto the surface of fine powders (such as ceramics, glass, quartz, or organic resins); metal compounds, such as alumina, aluminum nitride, or zinc oxide, and mixtures of two or more of these. Silver powder, aluminum powder, alumina powder, zinc oxide powder, aluminum nitride powder, or graphite are particularly suitable. Furthermore, if electrical insulation is required in the compositions of the present invention, powders based on metal oxides or powders based on metal nitrides are preferred, with alumina powder, zinc oxide powder, or aluminum nitride powder being particularly preferred.

[0080] The average particle size (as median particle size) of such thermally conductive or electrically conductive fillers is preferably in the range of 1 μm to 100 μm, and particularly preferably in the range of 1 μm to 50 μm.

[0081] While not particularly limited thereto, the amount of component (B) is 1% to 95% by weight, preferably 5% to 90% by weight, more preferably 10% to 90% by weight, even more preferably 20% to 85% by weight, and even more preferably 30% to 80% by weight, based on the total weight of the composition. This is because if the amount of component (B) falls within the above range, it is sufficient to exhibit the desired effect of component (B).

[0082] Component (C)

[0083] In this invention, component (C) is a characteristic component according to the invention and is used as a filler treatment agent to promote the flowability of the organosilicon and filler composition. Specifically, component (C) is a side-linked epoxy-functionalized siloxane represented by the following general formula (I):

[0084]

[0085] Where D represents R2SiO 2 / 2 Unit, wherein R is the same or different monovalent alkyl group without epoxy functional group each time it appears; U indicates the presence of R' n R (2-n) SiO 2 / 2 The epoxy group of the unit, wherein R is a monovalent alkyl group, and R' is the same or different monovalent organic group containing at least one ortho-epoxy group each time it appears, and n has a value of 1 to 2; M and M' each time they appear have the formula R3SiO 1 / 2 The same or different end-capping units, wherein R is the same or different monovalent alkyl group without epoxy groups each time it appears; x is an integer having a value of 10 to 1,000, and y is an integer having a value of 1 to 100. That is, the component (C) of the present invention must have at least one epoxy functional group on its side chain. Not wishing to be bound by theory, it is believed that the component (C) can promote the flowability of organosilicon and filler compositions by such side groups having epoxy functional groups. In particular, side-branched epoxy functional siloxanes such as component (C) can greatly promote flowability to a much higher level compared to siloxanes that have epoxy functional groups only at their ends (so-called "double-terminated epoxy functional siloxanes"). Furthermore, side-branched epoxy functional siloxanes such as component (C) can achieve comparable or even better flowability than other conventional alkoxy-based polymer filler treatments in the prior art without producing alcohols and incurring additional costs.

[0086] There is no particular upper limit to the x / y ratio, but if the x / y value is too low, there is a risk that the number of epoxy groups contained in component (C) will become too large, failing to promote flowability to the desired level. In other words, if the x / y value is too low, the epoxy equivalent of component (C) will become too low to achieve its desired effect. Therefore, to ensure the ability of component (C) to promote flowability, it is preferable to adjust the epoxy equivalent of component (C) to a suitable range. In some embodiments, component (C) has an epoxy equivalent of higher than 350 g / mol, preferably higher than 1,000 g / mol, more preferably higher than 2,000 g / mol, and most preferably higher than 3,000 g / mol.

[0087] In some embodiments, the side group R' independently has a main chain containing 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 2 to 12 carbon atoms, even more preferably 2 to 10 carbon atoms, even more preferably 3 to 8 carbon atoms, and even more preferably 4 to 5 carbon atoms. In some embodiments, the main chain of R' independently has one or two oxygen atoms between two adjacent carbon atoms. In some embodiments, an epoxy functional group is located at the end of R' and is independently attached to the end of R' via a direct bond or a linker. In some embodiments, the linker is selected from the group consisting of ether groups, ester groups, carbonyl groups, and urethane groups.

[0088] In some embodiments, R' may be exemplified by: glycidoxymethyl, glycidoxyethyl, glycidoxypropyl, glycidoxybutyl, glycidoxypentyl, glycidoxyhexyl, glycidoxyheptyl, glycidoxyoctyl, glycidoxynonyl, glycidoxydecyl, or similar glycidoxyalkyl groups, wherein the propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups contained in the above exemplary R' may be straight-chain or branched.

[0089] In some preferred embodiments, the filler treatment agent (C) is represented by the following general formula:

[0090]

[0091] Where R1, R2, and R3 independently represent side groups with epoxy functional groups, (n+m)≥1, p≥10. Such a specific filler treatment agent (C) can achieve a better flowability-enhancing effect.

[0092] While not particularly limited thereto, the amount of component (C) is 0.1% to 10% by weight, preferably 0.2% to 5% by weight, more preferably 0.3% to 3% by weight, even more preferably 0.4% to 2% by weight, even more preferably 0.5% to 1.5% by weight, and most preferably 0.8% to 1.2% by weight, based on the total weight of the composition. This is because if the amount of component (C) falls within the above range, it is sufficient to exhibit its effect of promoting flowability.

[0093] Other optional components

[0094] The compositions of the present invention may also contain or not contain chemical formula R f Si(OR g )3 alkyltrialkoxysilane (component D), wherein R f Each time it appears, it is independently an alkyl group having 1 to 12 carbon atoms; and R g Each time it appears, it is independently an alkyl group having 1 to 6 carbon atoms. R g Ideally, it is methyl to form a methoxy group attached to a silicon atom. Particularly desirable alkyltrialkoxysilanes are methyltrimethoxysilane, n-decyltrimethoxysilane, n-octyltrimethoxysilane, or mixtures thereof. Component (D) can be used to prevent filler sedimentation and extend the service life of the composition. Based on the weight of component (A), it can be present in amounts from 0% to 5% by weight, and can be 0% or more by weight, 0.05% or more by weight, 0.08% or more by weight, 0.10% or more by weight, 0.15% or more by weight, or even 0.2% or more by weight, while typically 5% or less by weight, and can be 4.0% or less by weight, 3.0% or less by weight, 2.0% or less by weight, 1.0% or less by weight, 0.5% or less by weight, or even 0.2% or less by weight.

[0095] The compositions of the present invention may also contain or exclude organopolysiloxanes (“crosslinking agents”, component (E)) having at least two or at least three silicon-bonded hydrogen atoms per molecule and excluding alkenyl groups. Typically, based on the weight of component (A), the amount of polyorganohydrosiloxane in the composition may be from 0.1 wt% to 20 wt%, and may be 0.1 wt% or more, 0.5 wt% or more, 1.0 wt% or more, 2.0 wt% or more, 3.0 wt% or more, 4.0 wt% or more, 5 wt% or more, or even 7 wt% or more, while typically 20.0 wt% or less, and may be 18.0 wt% or less, 16.0 wt% or less, 15.0 wt% or less, 12.0 wt% or less, 10.0 wt% or less, or even 8.0 wt% or less.

[0096] The compositions of the present invention may also contain or exclude a hydrosilylation catalyst (component (F)). Hydrosilylation catalysts are known in the art and are commercially available. Hydrosilylation catalysts include platinum (Pt) group metal catalysts. Based on the weight of component (A), the amount of catalyst is sufficient to provide from 1 ppm to 1000 ppm of platinum group metals, and may be 1 ppm or more, 5 ppm or more, 10 ppm or more, 20 ppm or more, or even 30 ppm or more, while typically 1,000 ppm or less, and may be 500 ppm or less, 300 ppm or less, 130 ppm or less, or even 100 ppm or less.

[0097] Furthermore, the compositions of the present invention may optionally comprise: organic solvents such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, hexane, and heptane; flame retardants such as aluminum hydroxide; antioxidants such as hindered phenol-based antioxidants; heat resistant agents such as iron oxide; plasticizers such as dialkylsiloxane oligomers capped at both ends of the molecular chain with hydroxydialkylsiloxy groups; and other pigments, thixotropic agents, and antifungal agents, provided that the compositions of the present invention do not impair the purpose of the present invention.

[0098] Methods for treating packing

[0099] In this invention, a method for treating fillers is also provided. This method includes mixing filler (B) with the aforementioned filler treatment agent (C) and then heating them under vacuum. Through the above steps, the method of this invention can treat the filler with an epoxy-functionalized siloxane that serves as a specific side-linked branch of the filler treatment agent (C), thereby greatly promoting the flowability of the organosilicon and filler composition.

[0100] Here, although it is noted that the aforementioned filler treatment agent (C) can greatly improve the flowability of the silicone and filler composition, since such a filler treatment agent (C) is used to treat filler (B), it is not necessarily necessary to carry out the above steps in the presence of the aforementioned organopolysiloxane (A). Therefore, in some embodiments, the filler (B) and the filler treatment agent (C) are mixed and heated under vacuum in the presence of the aforementioned organopolysiloxane (A). In some other embodiments, the filler (B) and the filler treatment agent (C) are mixed and heated under vacuum in the absence of the aforementioned organopolysiloxane (A).

[0101] The mixing time of the filler (B) and the filler treatment agent (C), the number of mixing stages, and the temperature and time of heating them are not particularly limited, and therefore can be easily determined as needed based on common sense, as long as they ensure that the filler (B) can be adequately treated by the filler treatment agent (C) to promote flowability. In some embodiments, the mixing of the filler (B) and the filler treatment agent (C) is divided into two or more stages. In some embodiments, the filler (B) and the filler treatment agent (C) are heated under vacuum at 100°C to 150°C, preferably 110°C to 140°C, more preferably 120°C to 130°C for 30 minutes to 120 minutes, preferably 45 minutes to 90 minutes, more preferably 60 minutes to 70 minutes.

[0102] Furthermore, in the absence of the aforementioned organopolysiloxane (A), the organopolysiloxane (A) can be added after the treatment of the filler (B) is completed, in the case of mixing and heating the filler (B) and the filler treatment agent (C) under vacuum, to obtain an organosilicon and filler composition with high fluidity.

[0103] Applications of filler treatment agent (C)

[0104] As described above, the filler treatment agent (C) can significantly improve the flowability of the silicone and filler composition by using it to treat the filler. Therefore, in this invention, the use of the filler treatment agent (C) described in the first aspect in treating fillers is also provided. For example, when using fillers to impart various characteristic advantages to the silicone composition (including higher modulus, thermal conductivity, electrical conductivity, and specific rheological behavior), it is preferable to treat the filler with the filler treatment agent (C) before or after adding the filler to the silicone composition.

[0105] Furthermore, as described above, by treating filler (B) with the aforementioned filler treatment agent (C), the resulting organosilicon and filler composition of the present invention exhibits high fluidity and is therefore preferably suitable for a variety of applications, particularly those requiring both filler and high fluidity, such as encapsulants, sealants, conformal coatings, and thermal interface materials. Therefore, in this invention, encapsulants, sealants, conformal coatings, and thermal interface materials are also provided, all obtained from the high-fluidity organosilicon and filler composition of the present invention. The encapsulants, sealants, conformal coatings, and thermal interface materials of the present invention exhibit high fluidity and thus can meet ultra-fluidity requirements.

[0106] [Example]

[0107] The following is a more detailed description of the invention with reference to embodiments. However, the invention is not limited to these embodiments. Unless otherwise specified, all parts and percentages are by weight.

[0108] Table 1 below lists information about the raw materials used in the examples:

[0109] Table 1: Raw materials used in the examples

[0110] [Examples 1 to 2 (Inv-1 to Inv-2) and Comparative Examples 1 to 7 (C-1 to C-7) of the present invention]

[0111] The present invention embodiments 1 to 2 and comparative examples 1 to 7 are as follows.

[0112] Preparation of Organosilicon and Filler Composition :

[0113] 1. Mixing

[0114] Add all ingredients (unless otherwise specified) to a 150mL mixing cup and mix via FlackTek. ™ Mix on a high-speed mixer for 1 minute (1000 rpm, 30 seconds and 1500 rpm, 30 seconds). Then scrape the mixture against the sides of the container using a FlackTek mixer. ™ Repeat the mixing twice with the high-speed mixer for 1 minute.

[0115] The mixture was then transferred to an Al cup, which was covered with an Al foil having several holes. The cup was then heated under vacuum at 120°C for 60 minutes.

[0116] 3. Cooling

[0117] After heating and vacuum treatment, the samples were cooled at room temperature for 7 days to provide organosilicon and filler compositions of Inv-1 to Inv-2 and C-1 to C-7.

[0118] Representative formulations of organosilicon and filler compositions of Inv-1 to Inv-2 and C-1 to C-7 are shown in Table 2.

[0119] Table 2: Representative formulations (unit: g)

[0120] Liquidity test :

[0121] Before the flowability test, manually mix samples of the silicone and filler compositions of Inv-1 to Inv-2 and C-1 to C-7 for 1 minute.

[0122] After mixing, 1 mL of sample was aspirated into a 2 mL syringe and then dispensed onto a pre-cleaned glass plate. The sample flowed into a circle on the plate. After 60 minutes, the sum of the horizontal and vertical diameters of the circle was measured. The results are summarized in millimeters (Table 3).

[0123] Table 3: Liquidity Results *Single-terminal alkoxy functional siloxanes are relatively more difficult to prepare (and more expensive) than side-chain epoxy siloxanes, and compared to Inv-1 and Inv-2, they will produce toxic alcohols (in this case, methanol) during filler treatment, and even at lower viscosities, they are only comparable to Inv-1 and even less effective than Inv-2.

[0124] Low molecular weight filler treatment agents (e.g., trimethoxysilanes, alkylsilanes) only result in poor flowability (C-1, C-2), and the flowability is improved by introducing side-chain amino, hydroxyl, and epoxysiloxanes (C-4, C-5, Inv-1, Inv-2). However, no significant improvement is observed when using terminal-type epoxysiloxanes (C-6). A possible explanation for this is topological differences, where terminal-type functionalized siloxanes (e.g., doubly terminal epoxysiloxanes) may tend to enhance interactions between fillers, thus not showing an improvement in flowability. When side-chain side group types are more likely to provide the siloxane backbone as a "covering layer" of the filler when functional groups are attached to the filler surface, this decouples undesirable interactions between filler particles or clusters, thereby promoting flowability.

[0125] For side-chain aminosiloxanes (C-4) and hydroxysiloxanes (C-5), although they are less effective at promoting flowability compared to side-chain epoxysiloxanes (Inv-1, Inv-2), they still show improvement compared to inert vinyl polymers (C-1). However, when the epoxy equivalent is too low, such as in C-7 (side-chain epoxysiloxane #1, epoxy equivalent of 350 g / mol), flowability will be poor. This scenario assumes that the length / amount of the organosilicon backbone in side-chain epoxysiloxane #1 is insufficient, which cannot provide adequate isolation between fillers.

[0126] When compared to conventional single-terminal alkoxy-based polymer filler treatment agents (such as single-terminal alkoxy-functionalized siloxanes in C-3), side-chain epoxy siloxanes can provide comparable or even better flowability at the same dosage (side-chain epoxy siloxane #2 in Inv-1, side-chain epoxy siloxane #3 in Inv-2). Conventional single-terminal alkoxy-functionalized siloxanes are relatively more difficult to prepare (and more expensive) than side-chain epoxy siloxanes, and compared to Inv-1 and Inv-2, they will produce toxic alcohols (methanol in the case of C-3) during filler treatment. Even with lower viscosity, the flowability-promoting ability of single-terminal alkoxy-functionalized siloxanes is only comparable to Inv-1, and even less effective than Inv-2. Therefore, side-chain epoxy siloxanes exhibit a significant advantage in promoting the flowability of filled silicone systems.

Claims

1. A silicone and filler composition, the silicone and filler composition comprising: (A) an organopolysiloxane; (B) a filler; and (C) a filler treating agent represented by the following general formula (I): Where D represents R2SiO 2 / 2 Unit, wherein R is the same or different monovalent alkyl group without epoxy functional group each time it appears; U indicates the presence of R' n R (2-n) SiO 2 / 2 The unit has an epoxy group, wherein R is a monovalent alkyl group, and R' is a monovalent organic group containing at least one ortho-epoxy group, and n has a value of 1 to 2; M and M' each time they appear have the formula R3SiO 1 / 2 The same or different end-capping units, wherein R is the same or different monovalent alkyl group without epoxy group each time it appears; x is an integer having a value of 10 to 1,000 and y is an integer having a value of 1 to 100, and the polymer has an epoxy equivalent greater than 350 g / mol.

2. The silicone and filler composition according to claim 1, wherein R' in the filler treating agent (C) independently has a main chain containing 1 to 20 carbon atoms.

3. The silicone and filler composition according to any one of claims 1 to 2, wherein the main chain of R' independently has one or two oxygen atoms between two adjacent carbon atoms.

4. The silicone and filler composition according to any one of claims 1 to 3, wherein the epoxy functional group is located at the end of R' and is independently connected to the end of R' via a direct bond or a linking group.

5. The silicone and filler composition according to claim 4, wherein the linking group is selected from the group consisting of an ether group, an ester group, a carbonyl group, and a urethane group.

6. The silicone and filler composition according to any one of claims 1 to 5, wherein the filler treating agent (C) is represented by the following general formula: where R1, R2, and R3 independently represent side groups having an epoxy functional group, (n + m) ≥ 1, and p ≥ 10.

7. The silicone and filler composition according to any one of claims 1 to 6, wherein, based on the total weight of the composition, the amount of the filler treating agent (C) is 0.1% to 10% by weight.

8. The silicone and filler composition according to any one of claims 1 to 7, wherein the filler (B) is one or more inorganic fillers selected from the group consisting of a heat-conductive filler, an electrically conductive filler, or a reinforcing filler.

9. The silicone and filler composition according to any one of claims 1 to 8, wherein, based on the total weight of the composition, the amount of the filler (B) is 1% to 95% by weight.

10. The silicone and filler composition according to any one of claims 1 to 9, wherein the organopolysiloxane (A) has a linear, branched, partially branched, cyclic, resinous, dendritic structure, or a combination comprising different structures.

11. The silicone and filler composition according to any one of claims 1 to 10, wherein the organopolysiloxane (A) comprises any combination of M siloxane units, D siloxane units, T siloxane units, and / or Q siloxane units.

12. The silicone and filler composition according to any one of claims 1 to 11, wherein the organopolysiloxane (A) has the following average unit formula (II): ； where each R is an independently selected substituent; 0 < a ≤ 0.99; 0 < b ≤ 0.99; 0 ≤ c ≤ 0.2; and 0 ≤ d ≤ 0.2, provided that a + b + c + d = 1.

13. The silicone and filler composition according to any one of claims 1 to 12, wherein the organopolysiloxane (A) is an organopolysiloxane having at least two alkenyl groups containing 2 to 12 carbon atoms per molecule.

14. The organosilicon and filler composition according to any one of claims 1 to 13, wherein the organopolysiloxane (A) has a viscosity of at least 10 mPa•s at 25°C.

15. The organosilicon and filler composition according to any one of claims 1 to 14, wherein the amount of the organopolysiloxane (A) is from 1% to 60% by weight based on the total weight of the composition.

16. The organosilicon and filler composition according to any one of claims 1 to 15, wherein the organosilicon and filler composition further comprises or does not contain the chemical formula R f Si(OR g )3 alkyltrialkoxysilane (D), wherein R f Each time it appears, it is independently an alkyl group having 1 to 12 carbon atoms; and R g Each time it appears, it is independently an alkyl group having 1 to 6 carbon atoms, R g Ideally, it should be methyl so that a methoxy group can be formed attached to a silicon atom.

17. The organosilicon and filler composition according to any one of claims 1 to 16, wherein the organosilicon and filler composition further comprises or does not contain an organosiloxane (E) having at least two or at least three silicon-bonded hydrogen atoms per molecule and being free of an alkenyl group.

18. The organosilicon and filler composition according to any one of claims 1 to 17, wherein the organosilicon and filler composition further comprises or does not contain a hydrosilylation catalyst (F).

19. A method for treating filler, the method comprising the steps of mixing the filler (B) with a filler treatment agent (C) according to any one of claims 1 to 18, and then heating them under vacuum.

20. The method according to claim 19, wherein the filler (B) and the filler treatment agent (C) are mixed and heated under vacuum in the presence of the organopolysiloxane (A) according to any one of claims 1 to 18.

21. The method according to claim 19, wherein, in the absence of the organopolysiloxane (A) according to any one of claims 1 to 18, the filler (B) and the filler treatment agent (C) are mixed and heated under vacuum.

22. The method according to any one of claims 19 to 21, wherein the mixing of the filler (B) and the filler treatment agent (C) is divided into two or more stages.

23. The method according to any one of claims 19 to 22, wherein the filler (B) and the filler treatment agent (C) are heated under vacuum at 100°C to 150°C for 30 to 120 minutes.

24. Use of the filler treatment agent (C) according to any one of claims 1 to 18 in the treatment of fillers.

25. An encapsulant obtained from an organosilicon and filler composition according to any one of claims 1 to 18.

26. A sealant obtained from an organosilicon and filler composition according to any one of claims 1 to 18.

27. A conformal coating obtained from an organosilicon and filler composition according to any one of claims 1 to 18.

28. A thermal interface material obtained from an organosilicon and filler composition according to any one of claims 1 to 18.

Images