Polymer treatment agent for surface modification

Abstract

The method comprises producing a modified filler composition, the method comprising contacting a filler with a polymer treatment agent, which is prepared from the reaction of at least one bifunctional organosilane with a polyfunctional nucleus having at least two nucleophilic functional groups and a number average molecular weight of at least 400 Da. The method comprises preparing a dispersion by mixing a modified filler, prepared by reacting a filler with at least one bifunctional organosilane and a polyfunctional nucleus having at least two nucleophilic functional groups and a number average molecular weight of at least 400 Da, with a polyether polyol or polyether polyamine.

Description

Technical Field

[0001] Embodiments relate to polymer treatment agents for the modification of surfaces and inorganic fillers, particularly for use in polymer-forming materials and polymer-forming systems.

[0002] Introduction Incorporating inorganic fillers into polymer compositions is an emerging technical approach for developing new materials with desirable properties suitable for specific applications such as biomedical materials (e.g., dental restorative materials), batteries, ceramics, composites, magnetic products, electronic device packaging, solid propellants, and adhesives. In some cases, inorganic fillers are applied at high volume ratios (i.e., greater than 20 volume %) to reach a threshold concentration that imparts specific functions such as thermal conductivity, electrical conductivity, and magnetic rheological behavior to the material. For example, highly filled polymer systems are common thermal interface materials (TIMs) for the electric vehicle and solar cell industries.

[0003] However, high concentrations of fillers often involve an increase in viscosity and energy dissipation from particle-particle interactions, which can cause difficulties during the dispersion of the filler in the polymer-forming components and during application to the substrate. To lower the viscosity of highly filled polymer composites for ease of processing, surface treatment can be used to increase the compatibility between the filler and the surrounding phase. However, existing surface treatments continue to provide limited improvement with respect to the consistent reduction of viscosity of high concentrations of inorganic fillers (e.g., greater than 20 volume % of inorganic fillers).

Summary of the Invention

[0004] In one aspect, embodiments of the present disclosure relate to a method comprising generating a modified filler composition, the method comprising contacting a filler with a polymer treatment agent prepared from a reaction of at least one bifunctional organosilane and a polyfunctional nucleus having at least two nucleophilic functional groups and a number average molecular weight of at least 400 Da.

[0005] In another embodiment, the method may include the step of preparing a dispersion by mixing a modified filler, which is prepared by reacting a filler with at least one bifunctional organosilane and a polyfunctional nucleus having at least two nucleophilic functional groups and a number average molecular weight of at least 400 Da, with a polyether polyol or polyether polyamine. [Modes for carrying out the invention]

[0006] Embodiments disclosed herein relate to polymer treatment agents for stabilizing fillers and increasing their compatibility with various polymers and polymer-forming systems. The polymer treatment agents disclosed herein may be products of a reaction between one or more bifunctional organosilanes and a polyfunctional nucleus having two or more nucleophilic functional groups and a number-average molecular weight of at least 400 Da.

[0007] Polymer treatment agents may be used to improve the interaction between fillers and polymer systems, and to improve the apparent viscosity and storage stability of polymer-forming components (e.g., polyol compositions and polyurethane-forming components). In some cases, polymer treatment agents can be used to enhance the interaction between fillers and polymer systems by introducing higher levels of functional value (e.g., by increasing the number of nucleophilic functional groups or alkoxysilane anchor groups). Filler particles and surfaces may also be treated to modify their overall hydrophobicity / hydrophilicity and compatibility between fillers and various polymer types (e.g., epoxy, polyurethane, acrylic).

[0008] Polymeric treatment agents can be prepared by reacting a polyfunctional nucleus having two or more nucleophilic functional groups with one equivalent or more of a difunctional organosilane. The silane functional groups of the polymeric treatment agent can react with functional groups on the surface of filler particles or substrates (for example, silanization of hydroxyl groups on a silica surface forms Si-O-Si bonds). Surface functional groups may be naturally present or introduced through various chemical processes (e.g., plasma oxidation) or reagents (e.g., the use of linkers, primers, or intermediate layers). Once anchored to the surface, the nucleophilic functional groups on the polyfunctional nucleus can interact with the polymer system or components through covalent and / or non-covalent interactions, potentially reducing viscosity and sedimentation behavior. The ratio of selected nucleophilic functional groups to silane functional groups may be modified by changing the equivalent amount of the difunctional organosilane reacting with the polyfunctional nucleus.

[0009] The polymer treatment agents disclosed herein may be applied to fillers and / or surfaces either before (ex situ) or in combination with (in situ) the components to form polymer systems (e.g., polyurethanes, epoxys, acrylic resins). In some cases, the polymer treatment agent may be combined with the filler as a pretreatment before introducing it into the polymer system or polymer-forming system (e.g., side A and / or side B). Using a polyurethane system as an example, the filler may be reacted with the polymer treatment agent, which can improve the storage and rheological properties of the treated component (e.g., isocyanate or isocyanate-reactive component) before or during the reaction that forms the polyurethane. The modified filler may be produced by combining the polymer treatment agent with the filler after its formation, or by reacting the filler with a bifunctional organosilane, followed by reacting this "activated" filler with a polyfunctional nucleus (e.g., polyol or polyamine). The modification of the filler may be carried out in the presence of other components, including solvents or additives, that do not substantially affect the modification chemistry.

[0010] Polymeric treatment agents can be prepared from polyfunctional nuclei obtained by reacting with one equivalent or more of a bifunctional organosilane. The polyfunctional nuclei may include polymers, copolymers, or oligomers having a functional value (number of nucleophilic functional groups) of 2 or more, for example, 2 to 10, or 2 to 8. As used herein, "nucleophilic functional group" refers to a functional group that donates an electron pair to form a covalent bond with an electrophile, such as hydroxyl, primary or secondary amine, thiol, phenol, azide, etc.

[0011] Polyfunctional nuclei can be derived from the skeletal structures of polyethers, polyesters, polydimethylsiloxanes, polycarbonates, polybutadienes, polyolefins, or mixtures or copolymers thereof. Polyfunctional nuclei are produced by polymerization or oligomerization using one or more starter compounds having >3 carbon atoms (e.g., sorbitol, glycerin) and one or more monomers (e.g., propylene oxide, butylene oxide, polyol, polyamine). Suitable polyfunctional nuclei include polyether polyols prepared from a starter compound and one or more alkylene oxides, such as ethylene oxide, propylene oxide, and / or butylene oxide. Examples of starter compounds, though not limited to them, include molecules having 1 to 8 hydroxyl groups per molecule, such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, triethanolamine, diethanolamine, diisopropanolamine, bisphenol A, glycerol, diglycerol, triglycerol, trimethylolpropane, di(trimethylolpropane)pentaerythritol, dipentaerythritol, tripentaerythritol, sugars such as sucrose and sorbitol, and sugar alcohols. With respect to the present invention only, it is understood that the polyether polyol may be a blend of any of these polyether polyols with one or more starter compounds, or the polyether polyol may be one or more starter compounds themselves. Polyether polyols may include polyols formed by reacting polyethers with copolymers of alkylene oxides containing block copolymers, as well as polyethers "capped" with hydroxyethyl and / or hydroxypropyl oligomers or polymers.

[0012] The polyfunctional nucleus can function as a skeleton or spacer that limits the steric effects between the anchor chemistry of the alkoxysilane and the nucleophilic functional group. The molecular weight of the polyfunctional nucleus can be selected so that an active hydrogen functional group is present. In some cases, the polyfunctional nucleus may have a molecular weight of 400 Da or more, 450 Da or more, 1000 Da or more, or in the range of 400 Da to 50,000 Da, 400 Da to 10,000 Da, or 400 Da to 5,000 Da.

[0013] In some cases, polyfunctional nuclei are selected to control hydrophilicity and compatibility with other polymer additives and phases. For example, polyfunctional nuclei can minimize the content of hydrophilic components such as polyethylene glycol and increase compatibility with polymer systems having nonpolar or aromatic characteristics.

[0014] The polymer treatment agent may be prepared by reacting a polyfunctional nucleus with one equivalent or more of a bifunctional organosilane. The bifunctional organosilane may have at least one electrophilic functional group (e.g., isocyanate, epoxide, carbodiimide) and at least one alkoxysilane (e.g., alkoxysilanes such as trimethoxysilane, dimethoxysilane, and triethoxysilane), and the alkoxysilane can form a Si-OM bond (where M represents an inorganic element such as Si, Al, Mg, or Zn) with an inorganic filler.

[0015] The difunctional organosilanes disclosed herein are “difunctional” in that they include at least one silane functionality and at least one electrophilic functionality. In some cases, the difunctional organosilane is Si(OR) n (R'Y) 4-nThe formula may have the following general chemical structure, where n is an integer from 1 to 3, R is independently a C1-C5 alkyl group, R' is a C1-C20 hydrocarbon, and Y is an electrophilic functional group. In some cases, R' is a linear or branched, saturated or unsaturated, cyclic or aromatic C1-C20 hydrocarbon. Y is an electrophilic functional group, where "electrophilic functional group" refers to the stereochemistry of an ion or atom that accepts an electron pair and forms a covalent bond with a nucleophile, such as isocyanates, epoxys, allyls, vinyls, carboxylic acids, anhydrides, succinates, aldehydes, acid chlorides, aziridines, carbodiimides, oxetanes, sulfonyl chlorides, etc. For example, difunctional organosilanes include 3-isocyanatopropyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, isocyanatomethyltrimethoxysilane, and triethoxysilylpropyl succinic anhydride.

[0016] Other examples of difunctional organosilanes include organopolysiloxanes having one or more functional groups, such as linear, branched, resinous, and polybranched organopolysiloxanes functionalized with propyl succinic anhydride; linear, branched, resinous, and polybranched organopolysiloxanes functionalized with methyl succinic anhydride; linear, resinous, and polybranched organopolysiloxanes functionalized with cyclohexenyl anhydride; linear, branched, resinous, and polybranched organopolysiloxanes functionalized with carboxylic acids, such as carboxydecyl-terminated oligomers or polymeric polydimethylsiloxanes; and linear, branched, resinous, and polybranched organopolysiloxanes functionalized with aldehydes, such as undecylenaldehyde-terminated oligomers or polymeric polydimethylsiloxanes.

[0017] The polymer treatment agent may have a molar ratio of polyfunctional nuclei to difunctional organosilane of up to 1:(f-1), where f represents the functional value of the polyfunctional nuclei. In some cases, the polymer treatment agent is prepared by reacting polyfunctional nuclei with at least one difunctional organosilane in a molar ratio in the range of 1:1 to 1:(f-1).

[0018] Polymeric treatment agents may be used to treat filler surfaces, substrates, and / or inorganic material particles. Fillers disclosed herein may include one or more of silica, silicates, aluminum trihydrate (ATH), natural or synthetic aluminum oxide (alumina), etc. Examples of fillers include inorganic particles such as silica (SiO2) particles, titania (TiO2) particles, zinc oxide (ZnO) particles, zirconia (ZrO2) particles, and alumina (Al2O3) particles. In some cases, the filler may have particles ranging from 0.1 to 10 microns. 10 , D in the range of 5 to 50 microns 50 , and D in the range of 50-200 microns 90 It may have.

[0019] In addition to the filler, a polymer treatment agent may be applied to the reinforcing material containing the nucleophile described above. Suitable reinforcing materials include any one or more of the following: glass fibers, carbon nanotubes, graphene, carbon fibers, polyester fibers, natural fibers, aramid fibers, nylon fibers, basalt fibers, boron fibers, silicon carbide fibers, asbestos fibers, whiskers, hard particles, metal fibers, and functionalized derivatives thereof. The polymer treatment agent may be applied to the filler as a pretreatment before being introduced into the polymer system or polymer-forming system (e.g., side A and / or side B). The concentration may vary depending on the properties of the treatment agent and the type of thermally conductive filler. The treatment agents disclosed herein may be added to the filler as a pretreatment in amounts of 0.5% to 10% by weight, 0.5% to 7.5% by weight, or 0.5% to 5% by weight, based on weight percent (wt%) of the filler. While this disclosure discusses types of fillers and particles, to avoid doubt, the treatment agents may also be applied to larger-sized substrates and parts with similar inorganic compositions, without departing from this disclosure.

[0020] The polymer treatment agent may be used in combination with one or more fillers and can be used in a variety of applications as a component of polyol and / or polyamine formulations for use in polymer systems, such as polyurethane materials and polyurethane hybrid materials (e.g., polyurethane acrylate hybrids). In some cases, the polymer system may include a polymer matrix obtained by combining two-component curable compositions. For example, the polymer system may include a multi-component polyurethane system having an isocyanate component ("side A") and an isocyanate-reactive component ("side B"). During application, side A and side B are mixed and a curing reaction is initiated at room temperature to form a selected polymer matrix. In some cases, the polymer treatment agent may be used separately or in combination with fillers in the presence of polyamines and / or polyols to form an isocyanate-reactive component.

[0021] In some cases, a filler modified with a polymer treatment agent can be used as a component in a polymer system (e.g., polyurethane or polyurethane hybrid) to prepare polyurethane articles including foams, composites, films, and high-density solids. In some cases, the polymer system may be formulated as a low-viscosity (e.g., <20 Pa·s, e.g., 2 Pa·s to 10 Pa·s) foam-forming composition containing the modified filler in a weight percentage of less than 60% by weight, for example, in the range of 10% to 60% by weight. The manufactured foams containing the modified filler can be used in applications known in the industry. For example, as a flexible foam used in vehicle parts, such as seats, armrests, dashboards or instrument panels, sun visors, door linings, sound insulation components, shoe soles, fabric interlayers, fixtures, furniture, and bedding.

[0022] The polymer system can also be formulated to have a high viscosity (e.g., >20 Pa·s) using a higher concentration of modified filler (e.g., greater than 60 wt%, 70%, or 80%). Polymer systems containing a high concentration of filler may be formulated as thermal conductive adhesives, gap fillers, and other thermal interface materials. The polymer system can also be applied to stationary energy storage applications in personal and commercial environments. The polymer system can be formulated to meet the constraints for automotive and mobility solutions (e.g., EV), but can be modified outside the scope of these constraints for other related electrical and stationary energy storage applications. For example, stationary storage applications can be formulated with a higher density / weight (greater than 1 g / mL) and a higher thermal conductivity (e.g., greater than 0.2 W / m·K), where concerns regarding overall weight and lack of external cooling are not driving factors.

[0023] While the formulation components and properties have been disclosed individually, it is contemplated that component elements (e.g., compounds in isocyanates or isocyanate-reactive components) can be included, excluded, or combined in any manner or partial combination using any of the above concentration ranges and sub-ranges contained therein. Further, the recited formulation properties can be similarly achieved by various combinations of the recited components within the recited ranges.

[0024] The numerical ranges disclosed herein include all values from the lower limit to the upper limit (including these) and all values therebetween. Unless stated to the contrary, not implied by the context, or not customary in the art, all parts and percentages are by weight and all test methods are the latest at the filing date of this disclosure.

Examples

[0025] The following examples are provided to illustrate embodiments of the invention but are not intended to limit its scope. All parts and percentages are by weight unless otherwise indicated. Table 1 lists the materials used in the following examples.

[0026]

Table 1

[0027] The polymer silanes used in the examples were prepared as follows. In the first step, all active hydrogen-containing chemical substances were dehydrated under a vacuum of 20 mbar while stirring at 130 °C until the water content reached less than 0.05% by weight. The dehydrated chemical substances were then cooled to room temperature under a nitrogen atmosphere before further use.

[0028] For the reaction of hydroxyl groups and isocyanate groups, the system was heated to 50 °C with stirring, and then, according to the formulations in Table 2 and Table 3, stoichiometric amounts of silane-containing chemical substances were added. After mixing at 50 °C for 30 minutes, the components were reacted at 80 - 85 °C for 1.5 hours and then at 88 - 92 °C for 1.5 hours. Then, the mixture was cooled to room temperature under a nitrogen atmosphere.

[0029] For the reaction of amine groups and epoxy groups, the system was stirred at room temperature, and then, according to the formulations in Table 2 and Table 3, stoichiometric amounts of epoxy-containing chemical substances and silane-containing chemical substances were added. The mixture was reacted at room temperature for 1.5 hours and then sealed under a nitrogen atmosphere for future use.

[0030]

Table 2

[0031]

Table 3

[0032] Polyol Compatibility Test <​​​​In the first step, all fillers were dehydrated in a vacuum oven at 130°C for 3 hours under a vacuum of 25 mbar. The active hydrogen-containing chemicals were dehydrated using the procedure described above. The sample formulations for each sample were prepared by mixing the components shown in Tables 4 to 7 and reacting the mixtures with stirring at 145°C for 3 hours under a vacuum of 25 mbar. The samples were then sealed in a nitrogen atmosphere and cooled to room temperature before testing.

[0034] Various shear rates (0.01~100s) -1 Viscosity tests were conducted at 25°C using a DHR-III rheometer (TA Instruments) with 40 mm parallel plates and a 0.5 mm gap.

[0035] The instability index (colloidal instability) of the sample was evaluated using a LUMiSizer 6513-37 (12 channels, LUM GmbH) after centrifuging 0.5 mL of the sample in a polyamide tube at 50°C and 2500 rpm for 1 hour. The instability index was obtained via the instrument's accompanying software, SEPView (trademark) 6.4.177.7135 (copyright) LUM GmbH - www.lum-gmbh.de.

[0036] [Table 4]

[0037] [Table 5]

[0038] [Table 6]

[0039] [Table 7]

[0040] As shown in Tables 4 and 5, the comparative examples generally exhibited higher viscosity and higher instability index values ​​compared to the samples of the present invention. Notably, Comparative Example C1 showed high viscosity and instability index due to the untreated filler and lack of treatment. C2 showed a slight decrease in viscosity and a slight improvement in stability when a commercially available low molecular weight surface modifier / stabilizer Z 6210 (decyltrimethoxysilane) was used as the filler. C3 showed an increase in viscosity at low shear, but the viscosity did not change at high shear. This lack of stability improvement was thought to be due to the short spacer (TPG-Si(OMet)3, mw=240g / mol) between the silane and hydroxyl groups of the bifunctional organosilane on the ATH.

[0041] In Examples I1 to I7 of the present invention, the fillers stabilized with the polymer treatment agent exhibited lower viscosity at both high and low shear rates, as well as greater colloidal stability (smaller instability index value), compared to C1 to C3, when the filler was added at a concentration of 40% by weight. This difference is thought to be due to the larger component, the polyfunctional nucleus (Mw ≥ 400 g / mol of the skeleton between active hydrogen and silane in the polymer treatment agent), which provides a greater intramolecular distance between the organosilane anchor and the reactive hydrogen.

[0042] C4 exhibited high viscosity, which is thought to be due to the low ratio of active hydrogen to silane groups on the polymer treatment agent (only 1:5), and also resulted in particle-to-particle aggregation of the filler, viscosity degradation, and colloidal stability. In comparison, I8, with an ATH content of 40 wt%, used glycidyl-based T-5000-Si(OMet)3 for the preparation of the polymer silane, and showed better performance in viscosity reduction and stability improvement compared to C4. With an ATH filler content of 50 wt%, C5 showed high viscosity and insufficient colloidal stability due to the untreated surface and increased filler content, while I9 showed viscosity reduction and stability improvement compared to C5.

[0043] C6, which contains a commercially available ATH filler with a wide size distribution and no surface modification, showed high viscosity and instability index. However, I10 showed improved viscosity and colloidal stability with the incorporation of the polymer treatment agent NC138-Si(OMet)3.

[0044] C9, containing Al2O3 filler, exhibited high viscosity and a high instability index, but the addition of the polymer treatment agent 222-056-Si(OMe)3 in I11 resulted in improved viscosity and colloidal stability.

[0045] C7, containing commercially available surface-treated fillers, exhibited high viscosity and high instability. C8 also showed low colloidal stability, which did not change with the addition of polymeric treatment agents. This lack of change was thought to be due to the unavailability of hydroxyl groups on the filler surface that could interact with the organosilane of the treatment agent. Similarly, the surface-treated Al2O3 filler in C10 showed high viscosity and a high instability index, which did not change in C11 with the addition of polymeric treatment agents, and may be due to the unavailability of hydroxyl groups for reaction with organosilane.

[0046] The above describes exemplary embodiments, but other and further embodiments may be devised without departing from their basic scope, and the scope of such embodiments will be determined by the following claims.

Claims

1. A method for producing a modified filler composition, Filler and, A polymer treatment agent, At least one type of bifunctional organosilane, and A polyfunctional nucleus having at least two nucleophilic functional groups and a number-average molecular weight of at least 400 Da, A polymer treatment agent prepared from the reaction, A method including the step of bringing into contact with

2. The method according to claim 1, wherein the polymer treatment agent comprises at least two nucleophiles.

3. The method according to claim 1, wherein the polymer treatment agent comprises at least two types of alkoxysilanes.

4. The method according to claim 1, wherein the polymer treatment agent is prepared by reacting the polyfunctional nucleus with at least one bifunctional organosilane in a molar ratio in the range of 1:1 to 1:(f-1), where f is the functional value of the polyfunctional nucleus.

5. The method according to claim 1, wherein the modified filler is prepared by combining the filler with at least one bifunctional organosilane and subsequently reacting it with the polyfunctional nucleus.

6. The method according to claim 1, wherein the modified filler composition further comprises a polyether polyol or a polyetheramine, and the modified filler is present in an amount of at least 50% by weight of the composition on a weight percentage basis.

7. The method according to claim 6, wherein the filler is contacted with the polymer treatment agent before being combined with a polyether polyol or polyetheramine.

8. A modified filler produced by the method described in claim 1.

9. A modified filler prepared by reacting a filler with at least one bifunctional organosilane and a polyfunctional nucleus having at least two nucleophilic functional groups and a number-average molecular weight of at least 400 Da, Polyether polyol or polyether polyamine, A method comprising the step of preparing a dispersion by mixing the following.

10. The method according to claim 9, wherein the modified filler is prepared by combining the filler with at least one bifunctional organosilane and subsequently reacting it with the polyfunctional nucleus.

11. The method according to claim 9, wherein the modified filler is prepared by combining the filler with at least one bifunctional organosilane and the polyfunctional nucleus in the presence of the polyether polyol or polyetheramine.

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