Encapsulated catalysts for one - component organopolysiloxanes and related methods

Abstract

Disclosed herein are particles having a platinum group catalyst fully encapsulated within a thermoplastic polymer. The particles can be used in curable organopolysiloxane compositions that also include an organopolysiloxane component.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 944,394, filed on December 6, 2019, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure relates to particles containing a catalyst suitable for use in curing a one - part silicone system. The present disclosure also relates to methods of making and using such particles.

Background Art

[0003] To cure certain types of compositions, contact between a curable component and a catalyst contained in the composition may be required. For example, in the case of a hydrosilylation - reaction - curable organopolysiloxane composition, the curable component in the composition is cross - linked by a hydrosilylation - reaction catalyst such as a platinum - group catalyst, but curing begins when the catalyst and the curable component come into contact. Therefore, for example, it is necessary to prevent the catalyst and the curable component from coming into contact with each other during storage until curing is required.

[0004] One way to avoid contact between the catalyst and the curable component is a so - called two - component composition, where the first part contains the catalyst and the second part contains the curable component. However, two - component compositions are not user - friendly because, for example, it is necessary to mix the two components immediately before use. Further, two - component compositions are complicated to handle and may even require complex devices for mixing.

[0005] Therefore, so - called one - component compositions in which the catalyst and the curable component are present in the same system can be used. In a one - component composition, the catalyst can be coated or micro - encapsulated to ensure that the catalyst and the curable component do not come into contact.

[0006] However, one-component curable organopolysiloxane compositions containing encapsulated catalysts can have problems with functioning consistently as desired between batches and functioning within certain parameters. For example, in conventional one-component curable organopolysiloxane compositions, it has been observed that during storage, the platinum group catalyst and the polysiloxane component come into contact, and changes occur over time due to the hydrosilylation reaction. As a result, the viscosity of the composition increases, causing the composition to cure. Further, typically, high cure temperatures (e.g., temperatures above 100 °C) are required for Pt to be released from the encapsulated particles, limiting their use in areas where other temperature-sensitive materials or components are involved. The catalyst release rate is not sufficient to achieve a snap cure at the required temperatures, especially in the lower cure temperature range (e.g., 30 - 100 °C).

[0007] Accordingly, there is a need for improved one-component compositions. Particles, compositions, and related methods are disclosed herein.

Summary of the Invention

Means for Solving the Problems

[0008] Particles are disclosed herein. The particles comprise at least two components: 1. a platinum group catalyst and 2. a molecular weight controlling thermoplastic polymer having a T g or softening temperature of at least 20 °C. The platinum group catalyst is completely encapsulated within the thermoplastic polymer. The molecular weight controlling thermoplastic polymer can be polystyrene or a copolymer thereof and has a weight average molecular weight (M w ) of about 500 g / mol to about 30,000 g / mol and a polydispersity index (PDI) of less than 2. In another embodiment, the molecular weight controlling thermoplastic polymer can be polymethyl methacrylate or a copolymer thereof and has an M w of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2. In another embodiment, the molecular weight controlling thermoplastic polymer can be polyacrylonitrile or a copolymer thereof and has an Mw and has a PDI of less than 2. By using the molecular weight-controlled thermoplastic polymers disclosed herein to completely encapsulate the platinum group catalyst, particles with an adjustable low activation temperature are provided. Such particles provide a reproducible system with low batch-to-batch variation. Such a system provides a reliable system with a repeatable catalyst release rate at a desired temperature, thereby resulting in a snap cure of the curable organopolysiloxane composition (e.g., a one-component curable organopolysiloxane composition).

[0009] Also disclosed herein is a curable organopolysiloxane composition. The curable organopolysiloxane composition comprises at least three components: 1. an average unit formula: R a SiO (4-a) / 2 (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, and "a" is a number from 1.0 to 2.4 and has at least an average of 1.5 alkenyl groups in the molecule), 2. an organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule, and 3. the particles disclosed herein.

[0010] Also disclosed herein is a method. The method uses the compositions and particles disclosed herein. The method includes the step of providing a curable organopolysiloxane composition disclosed herein. The curable organopolysiloxane composition is heated to a temperature effective for the thermoplastic polymer to melt and release the platinum group catalyst, thereby promoting the crosslinking reaction between the organopolysiloxane represented by the average unit formula: R a SiO (4-a) / 2 and the organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule to cure the curable organopolysiloxane composition.

[0011] Additional advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the aspects described below. The advantages described below will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects and together with the description serve to explain the principles of the invention. **Brief Description of the Drawings**

[0013]

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[0014] The present invention can be more easily understood by referring to the following detailed description of the present invention and the examples included therein.

[0015] Before disclosing and describing these particles, compositions, articles, systems, devices, and / or methods, it should be understood that, of course, they can vary and thus are not limited to a particular method or, unless otherwise specified, to particular reagents, since they can change. It should also be understood that the terms used herein are for the purpose of merely describing particular embodiments and are not intended to be limiting. Any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, but exemplary methods and materials are described herein.

[0016] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials related to the cited publications. The publications discussed herein are provided only for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such disclosure by virtue of prior invention. Further, the publication dates provided herein may be different from the actual publication dates and may require independent confirmation.

[0017] A. Definitions As used herein, the nomenclature of a compound can be given using common names as well as names assigned by recommendations of the International Union of Pure and Applied Chemistry (IUPAC) and Chemical Abstracts Service (CAS) (incorporated herein by reference) to the nomenclature. One of ordinary skill in the art can readily identify the structure of a compound and, when given, can name it by systematically shortening the structure of the compound using naming rules.

[0018] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0019] In this specification, ranges may be expressed as from "about" a particular value and / or to "about" another particular value. When such a range is expressed, further aspects include from one particular value and / or to another particular value. Similarly, when values are expressed as approximations by use of the antecedent "about", it should be understood that the particular value forms a further aspect. It should further be understood that each endpoint of each range is significant both in relation to the other endpoint and independently of the other endpoint. It is also understood that some values disclosed herein exist, and each value, in addition to the value itself, is disclosed herein as "about" that particular value. For example, if the value "10" is disclosed, "about 10" is also disclosed. It should also be understood that each unit between two particular units is also disclosed. For example, if 10 and 15 are disclosed, 11, 12, 13, and 14 are also disclosed.

[0020] References in this specification and the appended claims to the parts by weight of a particular element or component indicate the weight relationship between the element or component whose parts by weight are expressed and any other element or component or article. Thus, in a composition containing 2 parts by weight of component X and 5 parts by weight of component Y, X and Y are present in a weight ratio of 2:5 or 2 / 5 or 0.4, and are present in such ratio regardless of whether additional components are included in the compound. In addition, references in this specification and the appended claims to the molar ratio of a particular element or component indicate the molar relationship between the element or component in a composition or article whose molar ratio is expressed and any other element or component. Thus, in a composition containing 5 moles of component X and 2 moles of component Y, X and Y are present in a molar ratio of 5:2 or 5 / 2 or 2.5, and are present in such ratio regardless of whether additional components are included in the composition.

[0021] The weight percentage (wt%) of a component is based on the total weight of the formulation or composition in which the component is included, unless otherwise specified.

[0022] As used herein, the terms "optional" or "optionally" mean that the subsequently described event or circumstance may or may not occur, and the description includes both the case where the event or circumstance occurs and the case where it does not occur.

[0023] Unless otherwise specified, it is never intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, when a method claim does not actually recite an order to follow for its steps, or when the claims or specification do not otherwise specify that the steps should be limited to a particular order, no inference of order is intended in any respect. This applies to any possible implicit principles of interpretation, including logical matters regarding the arrangement of steps or operation flows, plain meaning derived from grammatical construction or punctuation, and the number or type of embodiments described herein.

[0024] Disclosed are the components used to make the particles and compositions disclosed herein, as well as those used within the methods disclosed herein. These and other compounds are disclosed herein, and where combinations, subsets, interactions, groups, etc. of these materials are disclosed, while it is not possible to explicitly disclose each specific reference to each of the various individual and collective combinations and permutations of these components, it is understood that each is specifically contemplated and described herein. For example, if a particular silicone composition is disclosed and considered, and several modifications that can be made to several compounds including the silicone composition are considered, unless otherwise specified, each and all combinations and permutations of the composition, as well as possible modifications, are specifically contemplated. Thus, if classes of compounds A, B, and C, as well as classes of silicone compositions D, E, and F, and examples of particles or compositions are disclosed, A-D is disclosed, and even if each is not individually listed, each is individually and collectively contemplated, meaning that combinations A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered and disclosed. Similarly, any subset or combination of these is also disclosed. Thus, for example, subgroups of A-E, B-F, and C-E would be considered disclosed. This concept applies to all aspects of this application, including but not limited to steps in the manufacture and use methods of silicone compositions. Thus, if there are various additional steps that can be carried out, it is understood that each of these additional steps can be carried out in any particular embodiment of the method of the invention, or combination of embodiments.

[0025] B. Particles Particles useful in one-component curable organopolysiloxane compositions are disclosed herein. Particles are disclosed herein, a) with a platinum group catalyst, b) having a T g or softening temperature of a molecular weight controlling thermoplastic polymer, and a. M of about 500 g / mol to about 30,000 g / mol w and a polystyrene or its copolymer having a polydispersity index (PDI) of less than 2, b. M of about 500 g / mol to about 30,000 g / mol w and a polymethyl methacrylate or its copolymer having a polydispersity index (PDI) of less than 2, c. M of about 500 g / mol to about 30,000 g / mol w and a polyacrylonitrile or its copolymer having a polydispersity index (PDI) of less than 2, a molecular weight-controlled thermoplastic polymer selected from the group consisting of, comprising the platinum group catalyst is completely encapsulated within the thermoplastic polymer.

[0026] The molecular weight-controlled thermoplastic polymer used in the disclosed particles has a narrow molecular weight and a narrow polydispersity index (PDI), enabling a lower and more defined activation temperature when the particles are used in a one-component curable organopolysiloxane composition. It is desirable to adjust the activation temperature for specific uses. Also, having a narrow molecular weight and a narrow PDI improves the reproducibility of the particles, meaning that each batch of particles exhibits substantially the same behavior with respect to the activation temperature. Having a large (e.g., greater than 2) PDI can cause each batch of particles to have significantly different activation temperatures, making the particles difficult to predict.

[0027] The catalyst is a hydrosilylation catalyst. In one aspect, the platinum group catalyst is selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir), and combinations thereof. For example, the platinum group catalyst can be platinum. In another example, the platinum group catalyst can be palladium. In yet another example, the platinum group catalyst can be ruthenium. In yet another example, the platinum group catalyst can be rhodium. In yet another example, the platinum group catalyst can be osmium. In yet another example, the platinum group catalyst can be iridium. Non-limiting specific hydrosilylation reaction catalysts include platinum black, platinum-supported alumina powder, platinum-supported silica powder, platinum-supported carbon powder, chloroplatinic acid, an alcoholic solution of chloroplatinic acid, a complex of platinum and an olefin, a complex of platinum and an alkenyl siloxane (e.g., divinyltetramethyldisiloxane), and a catalyst prepared by further diluting a complex of platinum and an alkenyl siloxane with an alkenyl siloxane, a siloxane oligomer, etc., a palladium-based catalyst (e.g., tetrakis(triphenylphosphine)palladium), and a rhodium-based catalyst.

[0028] In one aspect, the particles contain from about 0.01 wt% to about 50 wt% of a platinum group catalyst. For example, the particles can contain from about 0.01 wt% to about 40 wt% of a platinum group catalyst. In another embodiment, the particles can contain from about 0.01 wt% to about 30 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 0.1 wt% to about 50 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 0.1 wt% to about 40 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 0.1 wt% to about 30 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 0.1 wt% to about 20 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 0.1 wt% to about 10 wt% of a platinum group catalyst. In another embodiment, the particles can contain from about 1 wt% to about 10 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 2 wt% to about 10 wt% of a platinum group catalyst. In another embodiment, the particles can contain from about 10 wt% to about 50 wt% of a platinum group catalyst. In yet another embodiment, the particles can contain from about 20 wt% to about 50 wt% of a platinum group catalyst.

[0029] In one aspect, the molecular weight controlled thermoplastic polymer can have a T g or softening temperature of at least 30°C. For example, the molecular weight controlled thermoplastic polymer can have a T g or softening temperature of at least 40°C. In another embodiment, the molecular weight controlled thermoplastic polymer can have a T g or softening temperature of at least 50°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a T g or softening temperature of at least 60°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a T g or softening temperature of at least 70°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a T g or softening temperature of at least 80°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a T gOr it can have a softening temperature. In yet another embodiment, the molecular weight-controlled thermoplastic polymer has a T of 20°C to 100°C g Or it can have a softening temperature. In yet another embodiment, the molecular weight-controlled thermoplastic polymer has a T of 30°C to 100°C g Or it can have a softening temperature. In yet another embodiment, the molecular weight-controlled thermoplastic polymer has a T g Or it can have a softening temperature of 50°C to 100°C. In yet another embodiment, the molecular weight-controlled thermoplastic polymer has a T g Or it can have a softening temperature of 70°C to 100°C. In yet another embodiment, the molecular weight-controlled thermoplastic polymer has a T of 20°C to 80°C g Or it can have a softening temperature. In yet another embodiment, the molecular weight-controlled thermoplastic polymer has a T of 20°C to 60°C g Or it can have a softening temperature.

[0030] In one aspect, the molecular weight-controlled thermoplastic polymer can have a T of at least 20°C g temperature. For example, the molecular weight-controlled thermoplastic polymer can have a T of at least 40°C g can have. In another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of at least 50°C g can have. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of at least 60°C g can have. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of at least 70°C g can have. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of at least 80°C g can have. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of at least 90°C g can have. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of 20°C to 100°C g can have. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a T of 30°C to 100°C gcan have. In yet another embodiment, the molecular weight controlled thermoplastic polymer has a T of 50°C to 100°C g can have. In yet another embodiment, the molecular weight controlled thermoplastic polymer has a T of 70°C to 100°C g can have. In yet another embodiment, the molecular weight controlled thermoplastic polymer has a T of 20°C to 80°C g can have. In yet another embodiment, the molecular weight controlled thermoplastic polymer has a T of 20°C to 60°C g can have.

[0031] In one aspect, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 20°C. For example, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 40°C. In another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 50°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 60°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 70°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 80°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of at least 90°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of 20°C to 100°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of 30°C to 100°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of 50°C to 100°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of 70°C to 100°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of 20°C to 80°C. In yet another embodiment, the molecular weight controlled thermoplastic polymer can have a softening temperature of 20°C to 60°C.

[0032] In one aspect, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 20°C to 100°C. For example, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 40°C to 100°C. In another embodiment, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 50°C to 100°C. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 60°C to 100°C. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 30°C to 90°C. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 30°C to 60°C. In yet another embodiment, the molecular weight-controlled thermoplastic polymer can have a melting temperature of 60°C to 90°C.

[0033] In one aspect, the thermoplastic polymer is polystyrene or a copolymer thereof having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer can be polystyrene or a copolymer thereof having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer can be polystyrene or a copolymer thereof having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer can be polystyrene or a copolymer thereof having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer can be polystyrene or a copolymer thereof having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 1.1.

[0034] In one aspect, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol wand polystyrene or its copolymer having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.1.

[0035] In one aspect, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and polystyrene or its copolymer having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and can be polystyrene or its copolymer having a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol wand may be polystyrene or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0036] In one aspect, the thermoplastic polymer is polystyrene. In another aspect, the thermoplastic polymer is a copolymer of polystyrene. Non-limiting examples of copolymers of polystyrene include styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-ethylene-butylene copolymer, styrene-N-vinylpyrrolidone copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene (ABS) copolymer, styrene-allyl alcohol copolymer, and styrene-maleic anhydride copolymer.

[0037] In one aspect, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and is polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and may be polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.8. In another example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and may be polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.5. In yet another example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and may be polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.2. In yet another example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and may be polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0038] In one aspect, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol wand a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of from about 1,000 g / mol to about 15,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer has an M of from about 1,000 g / mol to about 15,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer has an M of from about 1,000 g / mol to about 15,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer has an M of from about 1,000 g / mol to about 15,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0039] In one aspect, the thermoplastic polymer has an M of from about 15,000 g / mol to about 30,000 g / mol w and a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of from about 15,000 g / mol to about 30,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer has an M of from about 15,000 g / mol to about 30,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer has an M of from about 15,000 g / mol to about 30,000 g / mol w and can be a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer has an M of from about 15,000 g / mol to about 30,000 g / molw and a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0040] In one aspect, the thermoplastic polymer is polymethyl methacrylate. In another aspect, the thermoplastic polymer is a copolymer of polymethyl methacrylate. Non-limiting examples of copolymers of polymethyl methacrylate include polymethyl methacrylate-styrene copolymers, polymethyl methacrylate-acrylate copolymers, and copolymers of polymethyl methacrylate and polymethacrylate having pendant groups (e.g., one or more n-butyl groups or n-hexyl groups).

[0041] In one aspect, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.8. In another example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.5. In yet another example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.2. In yet another example, the thermoplastic polymer has an M of about 500 g / mol to about 30,000 g / mol w and a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0042] In one aspect, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol wand a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer has an M of about 1,000 g / mol to about 15,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0043] In one aspect, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 2. For example, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.8. In another embodiment, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.5. In yet another embodiment, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol w and may be a polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.2. In yet another embodiment, the thermoplastic polymer has an M of about 15,000 g / mol to about 30,000 g / mol wand may be polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 1.1.

[0044] In one aspect, the thermoplastic polymer is polyacrylonitrile. In another aspect, the thermoplastic polymer is a copolymer of polyacrylonitrile. Non-limiting examples of copolymers of polyacrylonitrile include polyacrylonitrile-butadiene copolymers and polyacrylonitrile-butadiene-styrene (ABS) copolymers.

[0045] In one aspect, the particles have an average particle size of from about 0.01 μm to about 500 μm. For example, they can have an average particle size of from about 0.01 μm to about 300 μm. In another embodiment, they can have an average particle size of from about 0.01 μm to about 150 μm. In yet another embodiment, they can have an average particle size of from about 0.01 μm to about 100 μm. In yet another embodiment, they can have an average particle size of from about 0.01 μm to about 80 μm. In yet another embodiment, they can have an average particle size of from about 0.01 μm to about 50 μm. In yet another embodiment, they can have an average particle size of from about 0.01 μm to about 30 μm. In yet another embodiment, they can have an average particle size of from about 0.01 μm to about 20 μm. In yet another embodiment, they can have an average particle size of from about 1 μm to about 30 μm. In yet another embodiment, they can have an average particle size of from about 100 μm to about 300 μm. In yet another embodiment, they can have an average particle size of from about 100 μm to about 500 μm.

[0046] The particles disclosed herein can be made by emulsion techniques. For example, a platinum group catalyst and a thermoplastic polymer can be added to an oil / water system. The system can be sheared to cause micelle formation. The solvent can be removed to solidify the micelles. The micelles can be filtered, washed, and dried.

[0047] The particles disclosed herein can be produced using spray drying technology. For example, a platinum group catalyst and a thermoplastic polymer can be added to a solvent system. The solvent system dissolves the thermoplastic polymer. The particles can then be produced by spraying the solvent system as an aerosol. The particles can be washed and dried.

[0048] C. Composition A one-component curable organopolysiloxane composition containing the particles disclosed herein is disclosed herein. The curable organopolysiloxane composition cures when the platinum group catalyst contacts the siloxane component in the organopolysiloxane composition. This occurs when the organopolysiloxane composition is heated to a temperature that softens or melts the thermoplastic polymer, and the platinum group catalyst is exposed to the siloxane component in the organopolysiloxane composition, causing the organopolysiloxane composition to cure.

[0049] During storage, the organopolysiloxane composition is kept at a low temperature sufficient to prevent the thermoplastic polymer from softening or melting and the platinum group catalyst from being exposed to the siloxane component. During use, for example, when the organopolysiloxane composition is applied to a surface, heat is applied to the organopolysiloxane composition for a desired time, and the temperature of the organopolysiloxane composition increases until the thermoplastic polymer softens or melts due to the heat and the platinum group catalyst is exposed to the siloxane component.

[0050] A curable organopolysiloxane composition is disclosed herein, (A) Average unit formula: R a SiO (4-a) / 2 (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, and "a" is a number from 1.0 to 2.4, and has at least an average of 1.5 alkenyl groups in the molecule) represented by the organopolysiloxane, and (B) an organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule, (C) The particles disclosed in this specification, are included.

[0051] R a SiO (4-a) / 2 In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group. Examples of this monovalent hydrocarbon group include an alkyl group (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group, and hexyl group), an alkenyl group (e.g., vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, and heptenyl group), an aryl group (e.g., phenyl group, tolyl group, and xylyl group), an aralkyl group (e.g., benzyl group and phenethyl group), and a halogenated alkyl group (e.g., 3-chloropropyl group and 3,3,3-trifluoropropyl group). For example, at least an average of 1.5 R groups in the molecule are alkenyl groups as described above. The vinyl group and the hexenyl group can be alkenyl groups. The methyl group and the phenyl group can be silicon-bonded groups other than alkenyl groups.

[0052] The above R a SiO (4-a) / 2 In the formula, "a" is a number from 1.0 to 2.4. Examples of the molecular structure of such component (A) include a linear structure, a partially branched linear structure, a branched chain structure, a network structure, and a dendritic structure. Component (A) can be a mixture of two or more organopolysiloxanes having these molecular structures. That is, a can be either 1 ≤ a < 2 or 2 ≤ a < 2.4. The viscosity of the organopolysiloxane at 25°C is not limited, but can be in the range of 50 to 1,000,000 mPa·s (e.g., in the range of 100 to 500,000 mPa·s).

[0053] Formula R a SiO (4-a) / 2Examples of the organopolysiloxane include dimethylsiloxane-methylvinylsiloxane copolymer capped at both molecular ends with trimethylsiloxy groups, methylvinylpolysiloxane capped at both molecular ends with trimethylsiloxy groups, methylvinylsiloxane-methylphenylsiloxane copolymer capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer capped at both molecular ends with trimethylsiloxy groups, dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups, methylvinylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups, methylphenylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both molecular ends with dimethylvinylsiloxy groups, methylvinylsiloxane-methylphenylsiloxane copolymer capped at both molecular ends with dimethylvinylsiloxy groups, methylvinylsiloxane-diphenylsiloxane copolymer capped at both molecular ends with dimethylvinylsiloxy groups, dimethylvinylsiloxane-diphenylsiloxane copolymer capped at both molecular ends with dimethylvinylsiloxy groups, methylvinylpolysiloxane capped at one molecular end with trimethylsiloxy group and at the other molecular end with dimethylvinylsiloxy group, dimethylsiloxane-methylvinylsiloxane copolymer capped at one molecular end with trimethylsiloxy group and at the other molecular end with dimethylvinylsiloxy group, the unit represented by the formula: R3SiO 1 / 2 and the unit represented by the formula: SiO 4 / 2 organopolysiloxane containing the unit represented by the formula: RSiO 3 / 2 organopolysiloxane containing the unit represented by the formula: R2SiO 2 / 2 and the unit represented by the formula: RSiO 3 / 2 organopolysiloxane containing the unit represented by the formula: R2SiO 2 / 2 the unit represented by the formula: RSiO 3 / 2 the unit represented by the formula: SiO4 / 2 Organopolysiloxanes containing units represented thereby, and mixtures of two or more of these organopolysiloxanes. R in the above formula is the above-mentioned substituted or unsubstituted monovalent hydrocarbon group.

[0054] Formula R a SiO (4-a) / 2 As the organopolysiloxane of, it is also contemplated to use an organopolysiloxane mixture having an average of 1.5 alkenyl groups in the molecule by mixing the above organopolysiloxane having at least two alkenyl groups in the molecule with the following organopolysiloxane having no alkenyl group or less than two alkenyl groups in the molecule. Examples of such organopolysiloxanes having no alkenyl group or less than two alkenyl groups in the molecule include dimethylpolysiloxane capped at one molecular end with a dimethylvinylsiloxy group and at the other molecular end with a trimethylsiloxy group, methylphenylpolysiloxane capped at one molecular end with a dimethylvinylsiloxy group and at the other molecular end with a trimethylsiloxy group, dimethylsiloxane-methylvinylsiloxane copolymer capped at both molecular ends with trimethylsiloxy groups and having one vinyl group in the molecular side chain, dimethylpolysiloxane capped at both molecular ends with trimethylsiloxy groups, and methylphenylpolysiloxane capped at both molecular ends with trimethylsiloxy groups.

[0055] Component (B) in the curable organopolysiloxane composition is a crosslinking agent and is an organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule. For example, the organopolysiloxane can have at least an average of 2 silicon-bonded hydrogen atoms in the molecule. The bonding sites of the silicon-bonded hydrogen atoms can be at the molecular ends, molecular side chains, or both the molecular ends and molecular side chains. Examples of silicon-bonded groups other than hydrogen atoms include substituted or unsubstituted monovalent hydrocarbon groups (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group, and hexyl group), alkenyl groups (e.g., vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, and heptenyl group), aryl groups (e.g., phenyl group, tolyl group, and xylyl group), aralkyl groups (e.g., benzyl group and phenethyl group), and halogenated alkyl groups (e.g., 3-chloropropyl group and 3,3,3-trifluoropropyl group), and alkoxysilylalkyl groups (e.g., trimethoxysilylethyl group, methyldimethoxysilylethyl group, triethoxysilylethyl group, and trimethoxysilylpropyl group), alkoxy groups (e.g., methoxy group, ethoxy group, propoxy group), and glycidoxyalkyl groups (e.g., glycidoxypropyl group and glycidoxybutyl group). Examples of the molecular structure of the organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule include linear structure, partially branched linear structure, branched chain structure, network structure, and dendritic structure. The organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule can be a mixture of two or more organopolysiloxanes having these molecular structures. The viscosity at 25 °C of the organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule can be in the range of 1 to 500,000 mPa·s (e.g., in the range of 1 to 1,000 mPa·s).

[0056] Examples of organopolysiloxanes having at least 1.5 silicon-bonded hydrogen atoms in the molecule include, but are not limited to, methylhydrogenpolysiloxane capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer capped at both molecular ends with trimethylsiloxy groups, methylhydrogensiloxane-methylphenylsiloxane copolymer capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer capped at both molecular ends with trimethylsiloxy groups, dimethylpolysiloxane capped at both molecular ends with dimethylhydroxysiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer capped at both molecular ends with dimethylhydroxysiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymer capped at both molecular ends with dimethylhydroxysiloxy groups, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer capped at both molecular ends with dimethylhydroxysiloxy groups, units represented by the formula: R’3SiO 1 / 2 and units represented by the formula: SiO 4 / 2 organopolysiloxanes containing, units represented by the formula: R’ 3 / 2 organopolysiloxanes containing, units represented by the formula: R’2SiO 2 / 2 and units represented by the formula: R’SiO 3 / 2 organopolysiloxanes containing, units represented by the formula: R’2SiO 2 / 2 organopolysiloxanes containing, units represented by the formula: R’SiO 3 / 2 and units represented by the formula: SiO 4 / 2Organopolysiloxanes containing units represented by, methylhydrogen siloxane-methyl(trimethoxysilylethyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, methylhydrogen siloxane-methyl(trimethoxysilylethyl)siloxane-methyl(3-glycidoxypropyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogen siloxane-methyl(trimethoxysilylethyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogen siloxane-methyl(trimethoxysilylethyl)siloxane-methyl(3-glycidoxypropyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, methylhydrogen siloxane-methyl(triethoxysilylethyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, methylhydrogen siloxane-methyl(triethoxysilylethyl)siloxane-methyl(3-glycidoxypropyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogen siloxane-methyl(trimethoxysilylethyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogen siloxane-methyl(triethoxysilylethyl)siloxane-methyl(3-glycidoxypropyl)siloxane copolymers capped at both molecular ends with trimethylsiloxy groups, and mixtures of two or more of these organopolysiloxanes. R' in the above formula is a substituted or unsubstituted monovalent hydrocarbon group, and examples of this monovalent hydrocarbon group include the above alkyl group, alkenyl group, aryl group, aralkyl group, or halogenated alkyl group. In one aspect, the organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule can be a mixture of an organopolysiloxane having silicon-bonded hydrogen atoms only at both molecular ends and an organopolysiloxane having at least 3 silicon-bonded hydrogen atoms in the molecule for the excellent mechanical characteristics (especially elongation) of the cured product formed by this composition.

[0057] The content of the organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule is such that the amount of silicon-bonded hydrogen atoms in the organopolysiloxane having at least 1.5 silicon-bonded hydrogen atoms in the molecule is in the range of 0.05 to 20 mol (for example, in the range of 0.1 to 20 mol, in the range of 0.1 to 10 mol, etc.) per mole of alkenyl group in the organopolysiloxane represented by R a SiO (4-a) / 2 It can be in such an amount. When the content of the organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule is less than the lower limit of the above range, the composition tends to cure sufficiently, but when the content exceeds the upper limit of the above range, the composition tends to foam during curing, which reduces the mechanical characteristics of the cured product formed by the composition.

[0058] In one aspect, the curable organopolysiloxane composition, as an additional optional component for regulating the hydrosilylation reaction of the present composition, has an average unit formula R a SiO (4-a) / 2It further contains a reaction inhibitor in an amount of 0.001 to 5 parts by weight per 100 parts by weight of the organopolysiloxane represented thereby. Non-limiting examples of the reaction inhibitor include acetylene alcohols (e.g., 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 2-phenyl-3-butyn-2-ol, 2-ethynylisopropanol, 2-ethynylbutan-2-ol, and 3,5-dimethyl-1-hexyn-3-ol), silylated acetylene alcohols (e.g., trimethyl(3,5-dimethyl-1-hexyn-3-oxy)silane, methylvinylbis(3-methyl-1-butyn-3-oxy)silane, and ((1,1-dimethyl-2-propynyl)oxy)trimethylsilane), unsaturated carboxylic acid esters (e.g., diallyl maleate, dimethyl maleate, diethyl fumarate, diethyl fumarate, diallyl fumarate, and bis(methoxyisopropyl) maleate), conjugated en-yne compounds (e.g., 2-isobutyl-1-butene-3-yne, 3,5-dimethyl-3-hexene-1-yne, 3-methyl-3-pentene-1-yne, 3-methyl-3-hexene-1-yne, 1-ethynylcyclohexene, 3-ethyl-3-butene-1-yne, and 3-phenyl-3-butene-1-yne), and alkenyl group-containing cyclic siloxanes (e.g., 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane).

[0059] In one aspect, the curable organopolysiloxane composition further comprises a filler and a treating agent. Non-limiting examples of the filler include silica fillers (e.g., fumed silica, colloidal silica, precipitated silica, crystalline quartz, and diatomaceous earth), carbon fillers (e.g., carbon black, carbon fiber, carbon nanotube, graphite, graphene, and reduced graphene oxide), metal oxides (e.g., titanium dioxide, aluminum oxide, iron oxide, zinc oxide, and indium tin oxide), metals (e.g., silver and gold), calcium carbonate, microballoons (e.g., glass microballoons), and boron nitride. The filler can be pretreated or treated in situ with the treating agent. Non-limiting examples of the treating agent include silazanes (such as hexamethyldisilazane and divinyltetramethylsilazane), cyclic silazanes (such as dimethylcyclic silazane and 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasilazane), and low molecular weight silicone fluids (such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane). The filler used can be present in an amount of about 0 to 80% by weight, preferably 10 to 40% by weight. The amount of the treating agent is determined by the amount of the filler and the surface area of the filler, and can be present in an amount of 0 to 30% by weight, preferably 0.5 to 10% by weight.

[0060] In one aspect, the particles disclosed herein are present in an amount effective to promote the crosslinking of a curable organopolysiloxane composition by a hydrosilylation reaction. For example, the particles disclosed herein can be present in an amount of 0.05 wt% to 5 wt% based on the total weight of the curable organopolysiloxane composition. In another embodiment, the particles disclosed herein can be present in an amount of 0.5 wt% to 5 wt% based on the total weight of the curable organopolysiloxane composition. In yet another embodiment, the particles disclosed herein can be present in an amount of 1 wt% to 5 wt% based on the total weight of the curable organopolysiloxane composition. In yet another embodiment, the particles disclosed herein can be present in an amount of 3 wt% to 5 wt% based on the total weight of the curable organopolysiloxane composition. In yet another embodiment, the particles disclosed herein can be present in an amount of 0.05 wt% to 3 wt% based on the total weight of the curable organopolysiloxane composition. In yet another embodiment, the particles disclosed herein can be present in an amount of 0.05 wt% to 1 wt% based on the total weight of the curable organopolysiloxane composition. In yet another embodiment, the particles disclosed herein can be present in an amount of 0.05 wt% to 0.5 wt% based on the total weight of the curable organopolysiloxane composition.

[0061] In one aspect, the curable organopolysiloxane composition can be a homogeneous mixture of all the components present in the curable organopolysiloxane composition. For example, the curable organopolysiloxane composition can be a homogeneous mixture of organopolysiloxanes represented by the average unit formula: R a SiO (4-a) / 2 wherein the organopolysiloxane has at least an average of 1.5 silicon-bonded hydrogen atoms and the particles disclosed herein in the molecule. In one aspect, the particles disclosed herein can be uniformly dispersed with other components in the curable organopolysiloxane composition.

[0062] The curable organopolysiloxane composition can be prepared herein by mixing the components in the curable organopolysiloxane composition.

[0063] D. Method Also disclosed herein is a method of using the curable organopolysiloxane composition disclosed herein. The method is disclosed herein, a) providing a curable organopolysiloxane composition disclosed herein; b) heating the curable organopolysiloxane composition to a temperature effective to melt the thermoplastic polymer and release the platinum group catalyst, thereby promoting a crosslinking reaction between an organopolysiloxane represented by the average unit formula: R a SiO (4-a) / 2 and an organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule to cure the curable organopolysiloxane composition.

[0064] In one aspect, the temperature effective to melt the thermoplastic polymer is from about 30 °C to about 100 °C. For example, the temperature effective to melt the thermoplastic polymer can be from about 40 °C to about 100 °C. In another example, the temperature effective to melt the thermoplastic polymer is from about 60 °C to about 90 °C. When the thermoplastic polymer melts, the platinum group catalyst is exposed to the organopolysiloxane component of the curable organopolysiloxane composition, curing the curable organopolysiloxane composition.

[0065] In one aspect, the curing of the curable organopolysiloxane composition occurs over a period of greater than 0 minutes to 72 hours. For example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 72 hours. In another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 48 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 24 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 18 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 12 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 6 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 3 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 10 minutes to 1 hour. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 12 hours to 72 hours. In yet another example, the curing of the curable organopolysiloxane composition can occur over a period of greater than 24 hours to 72 hours.

[0066] In one aspect, providing a curable organopolysiloxane composition includes applying the curable organopolysiloxane composition to a surface. In one aspect, the surface can be a surface located indoors. In another aspect, the surface may require repair.

[0067] In one aspect, providing a curable organopolysiloxane composition includes molding, extruding, or calendering the curable organopolysiloxane composition. For example, providing a curable organopolysiloxane composition can include molding. In another aspect, providing a curable organopolysiloxane composition can include extruding. In another aspect, providing a curable organopolysiloxane composition can include calendering.

[0068] E. Aspect In view of the following disclosure, certain more particularly described aspects of the present invention are explained. However, these particularly recited aspects are not intended to have any limiting effect on any different claims including different teachings or more general teachings described herein, or the "specific" aspects should not be construed as being limited in any way other than the literal meaning of the language and formulas used therein.

[0069] Aspect 1: A particle comprising A) a platinum group catalyst and b) a molecular weight controlling thermoplastic polymer having a T or softening temperature of at least 20 °C, wherein i. the polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a polydispersity index (PDI) of less than 2, ii. the polymethyl methacrylate or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or iii. the polyacrylonitrile or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, and the platinum group catalyst is completely encapsulated within the thermoplastic polymer. g Or a molecular weight controlling thermoplastic polymer having a softening temperature, wherein i. the polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a polydispersity index (PDI) of less than 2, ii. the polymethyl methacrylate or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or iii. the polyacrylonitrile or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, and the platinum group catalyst is completely encapsulated within the thermoplastic polymer. w And a polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or a polymethyl methacrylate or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or a polyacrylonitrile or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, and the platinum group catalyst is completely encapsulated within the thermoplastic polymer. w And a polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or a polymethyl methacrylate or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or a polyacrylonitrile or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, and the platinum group catalyst is completely encapsulated within the thermoplastic polymer. w And a polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or a polymethyl methacrylate or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, or a polyacrylonitrile or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, and the platinum group catalyst is completely encapsulated within the thermoplastic polymer. Aspect 2: The particle according to Aspect 1, wherein the thermoplastic polymer is a polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a polydispersity index (PDI) of less than 2. w And a polystyrene or its copolymer having an M of about 500 g / mol to about 30,000 g / mol and a PDI of less than 2, and the platinum group catalyst is completely encapsulated within the thermoplastic polymer. Aspect 3: The particles according to aspect 1 or 2, wherein the polystyrene or its copolymer has an M of about 1,000 g / mol to about 15,000 g / mol. w Aspect 4: The particles according to aspect 2 or 3, wherein the polystyrene or its copolymer has a PDI of less than 1.5. Aspect 5: The particles according to aspect 2 or 3, wherein the polystyrene or its copolymer has a PDI of less than 1.2. Aspect 6: The particles according to aspect 1, wherein the thermoplastic polymer is polymethyl methacrylate or its copolymer having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 2. Aspect 7: The particles according to aspect 6, wherein the polymethyl methacrylate or its copolymer has an M of about 1,000 g / mol to about 15,000 g / mol. w Aspect 8: The particles according to aspect 6 or 7, wherein the polymethyl methacrylate or its copolymer has a PDI of less than 1.5. Aspect 9: The particles according to aspect 6 or 7, wherein the polymethyl methacrylate or its copolymer has a PDI of less than 1.2. Aspect 10: The particles according to aspect 1, wherein the thermoplastic polymer is polyacrylonitrile or its copolymer having an M of about 500 g / mol to about 30,000 g / mol w and a polydispersity index (PDI) of less than 2. Aspect 11: The particles according to aspect 10, wherein the polyacrylonitrile or its copolymer has an M of about 1,000 g / mol to about 15,000 g / mol. w Aspect 12: The particles according to aspect 10 or 11, wherein the polyacrylonitrile or its copolymer has a PDI of less than 1.5. Aspect 13: The particles according to aspect 10 or 11, wherein the polyacrylonitrile or its copolymer has a PDI of less than 1.2. Aspect 14: The particles according to any one of aspects 1 to 13, wherein the particles have an average particle size of about 0.01 μm to about 500 μm. Aspect 15: The particle according to any one of Aspects 1 to 14, wherein the particle contains from about 0.01% to about 50% by weight of a platinum group catalyst. Aspect 16: A curable organopolysiloxane composition comprising: (A) an average unit formula: R a SiO (4-a) / 2 (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, and "a" is a number from 1.0 to 2.4, and having at least an average of 1.5 alkenyl groups in the molecule), (B) an organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule, and (C) the particle according to any one of Aspects 1 to 15. Aspect 17: The curable organopolysiloxane composition according to Aspect 16, wherein the composition further comprises a reaction inhibitor in an amount of 0.001 to 5 parts by weight per 100 parts by weight of component (A). Aspect 18: The curable organopolysiloxane composition according to Aspect 16 or 17, wherein component (B) is present in an amount such that the amount of silicon-bonded hydrogen atoms in component (B) is from 0.05 to 20 mol per 1 mol of alkenyl group in component (A). Aspect 19: The curable organopolysiloxane composition according to any one of Aspects 16 to 18, wherein component (C) is present in an amount effective to promote crosslinking of the curable organopolysiloxane composition by a hydrosilylation reaction. Aspect 20: The curable organopolysiloxane composition according to any one of Aspects 16 to 19, wherein component (C) is uniformly dispersed in components (A) and (B). Aspect 21: The curable organopolysiloxane composition according to any one of Aspects 16 to 20, wherein the curable organopolysiloxane composition is a uniform mixture of components (A), (B), and (C). Aspect 22: A method comprising: a) providing a curable organopolysiloxane composition according to any one of Aspects 16 to 21; and b) heating the curable organopolysiloxane composition to a temperature effective to melt the thermoplastic polymer and release the platinum group catalyst, thereby promoting a crosslinking reaction between components (A) and (B) to cure the curable organopolysiloxane composition. Aspect 23: The method according to aspect 22, wherein the temperature effective for melting the thermoplastic polymer is from about 30°C to about 100°C. Aspect 24: The method according to aspect 22, wherein the temperature effective for melting the thermoplastic polymer is from about 60°C to about 90°C. Aspect 25: The method according to any one of aspects 22 to 24, wherein the curing of the curable organopolysiloxane composition occurs over a period of more than 0 minutes to 72 hours. Aspect 26: The method according to any one of aspects 22 to 25, wherein providing the curable organopolysiloxane composition comprises applying the curable organopolysiloxane composition to a surface. Aspect 27: The method according to any one of aspects 22 to 25, wherein providing the curable organopolysiloxane composition comprises molding, extruding, or calendering the curable organopolysiloxane composition.

Examples

[0070] F. Examples The following examples are presented to provide those skilled in the art with a complete disclosure and description of the manner in which the compounds, compositions, articles, devices, and / or methods described and summarized herein are made and evaluated. They are intended purely for purposes of illustration and are not intended to limit the scope of the invention as regarded by the inventors as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperatures, etc.), but some error and deviation should be accounted for. Unless otherwise indicated, parts are parts by weight, temperature is in °C or ambient temperature, and pressure is at or near atmospheric pressure. There are many variations and combinations of reaction conditions (e.g., concentrations of components, desired solvents, solvent mixtures, temperature, pressure, and other reaction zones, as well as conditions that can be used to optimize the purity and yield of the products obtained from the described processes). All that is required to optimize such process conditions is reasonable and routine experimentation.

[0071] Examples are provided herein that illustrate the preparation of non-limiting and exemplary particles disclosed herein using molecular weight controlled polystyrene (PS) and molecular weight controlled poly(methyl methacrylate) (PMMA). Encapsulated Pt particles were prepared using both an emulsion approach and a spray drying approach. The two approaches are the same for the purpose of preparing the particles and should not be limited to a particular thermoplastic polymer. Examples 1 and 2 are the preparation of encapsulated Pt particles using molecular weight controlled PS, and Example 3 is a control example using conventional PS (M w and PDI are outside the scope of the particles disclosed herein). Example 4 is the evaluation of PS particles for use in a one-part addition-curing silicone composition. Examples 5 and 6 are the preparation of encapsulated Pt particles using molecular weight controlled PMMA by a spray drying process and a control example using conventional PMMA (M w and PDI are outside the scope of the particles disclosed herein), respectively. Example 7 is the evaluation of PMMA particles for use in a one-part addition-curing silicone composition.

[0072] i. Example 1 (Encapsulated Pt using molecular weight controlled PS) A flask was charged with 400 g of methylene chloride and then 15 g of low molecular weight PS (M w= 1800 Daltons, PDI = 1.04) was charged. The solution was stirred using a magnetic stirrer until the polystyrene was dissolved, and then 3.0 g of a calstet catalyst (Pt content of about 3 wt%) in an isopropyl alcohol solution was charged into this solution and mixed until homogeneous. Another flask charged with 600 g of deionized water was charged with 15 g of polyvinyl alcohol (PVA) and mixed until the solution became visually clear. A three-neck 12 L flask equipped with an air-driven stir bar, a thermocouple, a condenser, and a heating mantle was charged with 350 mL of the PVA solution and 200 mL of deionized water. The stir bar was activated, and then 180 mL of the above methylene chloride solution was added dropwise. After the addition, 900 mL of deionized water was charged into the emulsion mixture. Then, nitrogen (N2) purge (2 liters per minute) was applied to the flask, and the mixture was gradually heated to 40 °C within 4 hours and held for an additional 6 hours while purging with N2. The final mixture was milky white, and fine particles settled to the bottom of the flask. The fine particles were then isolated by centrifugation (3500 rpm), washed with isopropyl alcohol and deionized water, and finally dried at room temperature under vacuum. The resulting catalyst was used to prepare Composition A.

[0073] ii. Example 2 (Encapsulated Pt Using Molecular Weight-Controlled PS) The same process as described in Example 1 was used, but polystyrene with a different molecular weight was used. The flask was charged with 400 g of methylene chloride, and then 15 g of low molecular weight PS (M w(with a molecular weight of 4000 Daltons and a PDI of 1.04) was charged. The solution was stirred using a magnetic stirrer until the polystyrene was dissolved, and then 3.0 g of a calstedt catalyst (Pt content of about 3 wt%) in an isopropyl alcohol solution was charged into this solution and mixed until homogeneous. Another flask filled with 600 g of deionized water was charged with 15 g of PVA and mixed until the solution was clearly transparent. A three-neck 12 L flask equipped with an air-driven stir bar, a thermocouple, a condenser, and a heating mantle was charged with 350 mL of the PVA solution and 200 mL of deionized water. The stir bar was activated, and then 180 mL of the above-mentioned methylene chloride solution was added dropwise. After the addition, 900 mL of deionized water was charged into the emulsion mixture. Then, N2 purge (2 liters per minute) was applied to the flask, and the mixture was gradually heated to 40 °C within 4 hours and held for an additional 6 hours while purging with N2. The final mixture was milky white, and fine particles settled to the bottom of the flask. The fine particles were then isolated by centrifugation (3500 rpm), washed with isopropyl alcohol and deionized water, and finally dried at room temperature under vacuum. The resulting catalyst was used to prepare Composition B.

[0074] iii. Example 3 (Encapsulated Pt Using Conventional PS) - Control The same process as described in Example 1 was used, but polystyrene having a molecular weight and PDI outside the range of the particles disclosed herein was used. The flask was charged with 400 g of methylene chloride, and then 15 g of conventional PS (M w(with a weight-average molecular weight of 350 kDa and a PDI of 2.2) was charged. The solution was stirred using a magnetic stirrer until the polystyrene was dissolved, and then 3.0 g of a Karstedt catalyst (Pt content of about 3 wt%) in an isopropyl alcohol solution was charged into this solution and mixed until homogeneous. Another flask filled with 600 g of deionized water was charged with 15 g of PVA and mixed until the solution became clearly transparent. A three-neck 12 L flask equipped with an air-driven stir bar, a thermocouple, a condenser, and a heating mantle was charged with 350 mL of the PVA solution and 200 mL of deionized water. The stir bar was activated, and then 180 mL of the above-mentioned methylene chloride solution was added dropwise. After the addition, 900 mL of deionized water was charged into the emulsion mixture. Then, N2 purge (2 liters per minute) was applied to the flask, and the mixture was gradually heated to 40 °C within 4 hours and held for an additional 6 hours while purging with N2. The final mixture was milky white, and fine particles precipitated at the bottom of the flask. The fine particles were then isolated by centrifugation (3500 rpm), washed with isopropyl alcohol and deionized water, and finally dried at room temperature under vacuum. The resulting catalyst was used to prepare Composition C.

[0075] iv. Example 4 (Evaluation of Encapsulated Pt in Different PSs) The performance of the encapsulated catalysts in different PSs prepared as described above was tested in a one-component silicone composition containing a silicone substrate (96.6 wt%), a polymethylhydrogen-dimethylsiloxane (2 - 20 cST) crosslinking agent (2.9 wt%), and an encapsulated Pt catalyst (0.5 wt%). The silicone substrate described above was dimethylvinylsiloxy-blocked polydimethylsiloxane (5 kcP, 70 wt%), trimethylsilyl-treated fumed silica (surface area 200 m 2 / g, 17 wt%), and crystalline silica (Min-U-Sil 10, 13 wt%). The one-component composition was uniformly mixed by a Flack Teck DAC-400 mixer. Using the encapsulated Pt catalysts prepared from Examples 1 to 3, three compositions (shown as Compositions A, B, and C) were obtained. The curing profiles of the three compositions were evaluated by a controlled stress rheometer (CSR, TA instrument).

[0076] v. Example 5 (Encapsulated Pt using molecular weight-controlled PMMA) The flask was filled with 400 g of methylene chloride, and then 15 g of low molecular weight PMMA (M w = 5000 daltons, PDI = 1.06) was filled. The solution was stirred using a magnetic stirrer until the PMMA was dissolved, and then 3.0 g of a calixtet catalyst (Pt content of about 3 wt%) in an isopropyl alcohol solution was filled into this solution and mixed until homogeneous. The solution was spray-dried by a spray dryer (Buchi B290) at an inlet temperature of 65 °C under a nitrogen flow. By this process, 11 g of encapsulated particles were obtained, which were then washed with deionized water (500 mL) and isopropyl alcohol (250 mL) with stirring. The washing solvent was removed by centrifugation (3500 rpm), and the obtained particles were dried at room temperature under vacuum. Using the obtained catalyst, Composition D was prepared.

[0077] vi. Example 6 (Encapsulated Pt using conventional PMMA) - Control The same process as described in Example 5 was used, but PMMA having a molecular weight and PDI outside the range of the particles disclosed herein was used. A flask was filled with 400 g of methylene chloride, and then 15 g of a molecular weight-controlled PMMA (Mw = 76 kDa, PDI = 2.34) was filled. The solution was stirred using a magnetic stirrer until the PMMA was dissolved, and then 3.0 g of a Karstedt catalyst (Pt content of about 3 wt%) in an isopropyl alcohol solution was filled into this solution and mixed until homogeneous. The solution was spray-dried by a spray dryer (Buchi B290) at an inlet temperature of 65 °C under a nitrogen flow. By this process, 10 g of encapsulated particles were obtained, which were then washed with deionized water (500 mL) and isopropyl alcohol (250 mL) while stirring. The washing solvent was removed by centrifugation (3500 rpm), and the obtained particles were dried at room temperature under vacuum. Using the obtained catalyst, Composition E was prepared.

[0078] vii. Example 7 (Evaluation of Encapsulated Pt in Different PMMAs) The performance of the encapsulated catalysts in different PMMAs prepared as described above was tested in a one-component silicone composition containing a silicone substrate (96.6 wt%), a polymethylhydrogen-dimethylsiloxane (2 - 20 cST) crosslinking agent (2.9 wt%), and an encapsulated Pt catalyst (0.5 wt%). The above-mentioned silicone substrate consists of dimethylvinylsiloxy-blocked polydimethylsiloxane (5 kcP, 70 wt%), trimethylsilyl-treated fumed silica (surface area 200 m 2 / g, 17 wt%), and crystalline silica (Min-U-Sil 10, 13 wt%). The one-component composition was uniformly mixed by a Flack Teck DAC-400 mixer. Using the encapsulated Pt catalysts prepared from Examples 5 and 6 respectively, two compositions (shown as Composition D and E) were obtained. The curing profiles of the two compositions were evaluated by a controlled stress rheometer (CSR, TA instrument).

[0079] Figure 1 shows the curing profiles of compositions A, B, and C monitored by CSR. The temperature was increased at a rate of 10 °C / min to 25 °C to 100 °C for composition A, 25 °C to 120 °C for composition B, and 25 °C to 150 °C for composition C.

[0080] Figure 2 shows the curing profiles of compositions D and E monitored by CSR. The temperature was increased at a rate of 10 °C / min to 25 °C to 150 °C.

[0081] As shown in Figure 1, a characteristic activation temperature (defined as the starting temperature when the storage modulus began to increase exponentially) was detected by CSR. Compositions A and B showed significantly lower activation temperatures (68 °C and 89 °C, respectively) compared to composition C (114 °C). This difference is due to the use of molecular weight-controlled PS as the encapsulating agent for the calixtet catalyst in compositions A and B, while conventional PS was used in composition C. Furthermore, the sharp increase in the storage modulus of both compositions A and B at the corresponding activation temperatures (i.e., the slope of the curing profile) indicates snap curing at a lower temperature compared to composition C. When using PMMA (a thermoplastic polymer different from PS) to encapsulate the Pt catalyst (Examples D and E), the same behavior was confirmed that the activation temperature can be adjusted by the molecular weight of PMMA. As shown in Figure 2, molecular weight-controlled PMMA (composition D) results in a low activation temperature of 88 °C, while conventional PMMA results in an activation temperature of 110 °C. As shown in Figures 1 and 2, the molecular weight-controlled thermoplastic polymers show a softening temperature lower than the glass transition temperature (T g ) or their corresponding permanent T g Therefore, such encapsulated Pt catalysts can be released from the particles and start to cure at a lower temperature (e.g., below 100 °C) compared to the corresponding standard PS or PMMA.

[0082] Table 1 shows the activation temperatures determined by CSR for Compositions A - E, and the onset glass transition temperatures (T g ) determined by differential scanning calorimetry (TA instrument) of PS and PMMA used as encapsulating materials. The lower T g of the molecular weight - controlled PS and PMMA is shown to be related to the low activation temperature of the composition.

[0083]

Table 1

[0084] Figure 3 shows the isothermal curing profiles by CSR for Composition A at 50 °C, 60 °C, 70 °C, and 80 °C. Figure 4 shows the isothermal curing profiles by CSR for Composition B at 70 °C, 80 °C, 85 °C, and 90 °C. Figure 5 shows the isothermal curing profiles by CSR for Composition C at 100 °C, 110 °C, and 120 °C. Figure 6 shows the isothermal curing profiles by CSR for Composition D at 60 °C, 70 °C, 80 °C, and 90 °C. Figure 7 shows the isothermal curing profiles by CSR for Composition E at 80 °C, 90 °C, 100 °C, and 110 °C.

[0085] As shown in Figures 3 - 7, the isothermal curing profiles of Compositions A - E at different temperatures were recorded by CSR. In the case of the encapsulated Pt catalyst prepared from PS, Composition A showed snap - curing when the temperature exceeded 70 °C and almost no curing when the temperature was 50 °C. Compositions B and C showed similar snap - curing when the temperatures exceeded 85 °C and 120 °C, respectively. For the encapsulated Pt catalyst using PMMA, Compositions D and E showed snap - curing when the temperatures exceeded 90 °C and 110 °C, respectively. Furthermore, the room - temperature stability of the three compositions was monitored. All three samples showed no curing over a period of 6 months. The above results confirmed that the molecular weight - controlled PS for use in encapsulating Pt - group catalysts can enable one - component addition - curing silicone compositions with both low activation temperatures and excellent storage life at room temperature.

Claims

1. Particles comprising: a) a platinum group catalyst and b) a molecular weight-controlled thermoplastic polymer having a T ｇ or softening temperature of at least 20 °C, i. M of 500 g / mol to 30,000 g / mol ｗ and polystyrene or its copolymer having a polydispersity index (PDI) of less than 2 ii. M having a weight average molecular weight of from 500 g / mol to 30,000 g / mol ｗ and a polymethyl methacrylate or a copolymer thereof having a PDI of less than 2 iii. M of 500 g / mol to 30,000 g / mol ｗ and polyacrylonitrile or a copolymer thereof having a PDI of less than 2 a molecular weight-controlled thermoplastic polymer selected from the group consisting of and wherein the platinum group catalyst is completely encapsulated within the molecular weight-controlled thermoplastic polymer.

2. The molecular weight-controlled thermoplastic polymer is polystyrene or a copolymer thereof having an M of 500 g / mol to 30,000 g / mol ｗ The particle according to claim 1, which is polystyrene or a copolymer thereof having a polydispersity index (PDI) of less than 2.

3. The polystyrene or its copolymer has an M of 1,000 g / mol to 15,000 g / mol ｗ The particle according to claim 1 or 2, which has such an M value.

4. The particles according to claim 2 or 3, wherein the polystyrene or its copolymer has a PDI of less than 1.

5.

5. The particles according to claim 2 or 3, wherein the polystyrene or its copolymer has a PDI of less than 1.

2.

6. The molecular weight-controlled thermoplastic polymer has an M of 500 g / mol to 30,000 g / mol ｗ The particle according to claim 1, which is a polymethyl methacrylate or a copolymer thereof having a polydispersity index (PDI) of less than 2.

7. The polymethyl methacrylate or its copolymer has an M of 1,000 g / mol to 15,000 g / mol ｗ The particle according to claim 6, having the same.

8. The particles according to claim 6 or 7, wherein the polymethyl methacrylate or its copolymer has a PDI of less than 1.

5.

9. The particles according to claim 6 or 7, wherein the polymethyl methacrylate or its copolymer has a PDI of less than 1.

2.

10. The molecular weight-controlled thermoplastic polymer has an M of 500 g / mol to 30,000 g / mol ｗ The particle according to claim 1, which is polyacrylonitrile or a copolymer thereof having a polydispersity index (PDI) of less than 2.

11. The polyacrylonitrile or its copolymer has an M of 1,000 g / mol to 15,000 g / mol ｗ The particle according to claim 10, which has the above property.

12. The particles according to claim 10 or 11, wherein the polyacrylonitrile or its copolymer has a PDI of less than 1.

5.

13. The particles according to claim 10 or 11, wherein the polyacrylonitrile or its copolymer has a PDI of less than 1.

2.

14. The particles according to any one of claims 1 to 13, having an average particle size of 0.01 μm to 500 μm.

15. The particles according to any one of claims 1 to 14, containing 0.01% to 50% by weight of the platinum group catalyst.

16. A curable organopolysiloxane composition comprising: (A) an organopolysiloxane represented by the average unit formula: RaSiO （４－ａ）／２ (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, and "a" is a number from 1.0 to 2.4, and having at least an average of 1.5 alkenyl groups in the molecule) and (B) an organopolysiloxane having at least an average of 1.5 silicon-bonded hydrogen atoms in the molecule, and (C) the particles according to any one of claims 1 to 15. A curable organopolysiloxane composition.

17. The curable organopolysiloxane composition according to claim 16, further comprising a reaction inhibitor in an amount of 0.001 to 5 parts by weight per 100 parts by weight of component (A).

18. The curable organopolysiloxane composition according to claim 16 or 17, wherein component (B) is present in an amount such that the amount of silicon-bonded hydrogen atoms in component (B) is 0.05 to 20 mol per 1 mol of alkenyl groups in component (A).

19. The curable organopolysiloxane composition according to any one of claims 16 to 18, wherein component (C) is present in an amount effective for promoting the crosslinking of the curable organopolysiloxane composition by a hydrosilylation reaction.

20. The curable organopolysiloxane composition according to any one of claims 16 to 19, wherein component (C) is uniformly dispersed in components (A) and (B).

21. The curable organopolysiloxane composition according to any one of claims 16 to 20, wherein the curable organopolysiloxane composition is a homogeneous mixture of components (A), (B) and (C).

22. a) providing a curable organopolysiloxane composition according to any one of claims 16 to 21; b) heating the curable organopolysiloxane composition to a temperature effective for melting the molecular weight controlling thermoplastic polymer and releasing the platinum group catalyst, thereby promoting the crosslinking reaction between components (A) and (B) to cure the curable organopolysiloxane composition; A method comprising:

23. The method according to claim 22, wherein the temperature effective for melting the molecular weight controlling thermoplastic polymer is 30°C to 100°C.

24. The method according to claim 22, wherein the temperature effective for melting the molecular weight controlling thermoplastic polymer is 60°C to 90°C.

25. The method according to any one of claims 22 to 24, wherein the curing of the curable organopolysiloxane composition occurs over a period of more than 0 minutes to 72 hours.

26. The method according to any one of claims 22 to 25, wherein the step of providing the curable organopolysiloxane composition includes applying the curable organopolysiloxane composition to a surface.

27. The method according to any one of claims 22 to 25, wherein the step of providing the curable organopolysiloxane composition includes molding, extruding, or calendering the curable organopolysiloxane composition.

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