Reworkable polymer composition having dynamic crosslinking

Abstract

To provide a new class of polymer elastomers using silicon-oxygen backbones that can be reprocessable thermally at temperatures beyond a required scope of applications, while maintaining advantages of commercial silicones such as high tensile strength, thermal stability, and food contact safety.SOLUTION: A polymer composition having covalent bonding networks alterable by thermally activated bond exchanges creating dynamic crosslinks comprises: a silicon-oxygen backbone chain elastomer for creating a polymer network; a non-agglomerating filler dispersed within and bonded to the polymer network; a catalyst for facilitating a condensation reaction; a silane-based crosslinker including methoxy or ethoxy groups; at least one dynamic bond activator promoting Si-O bond exchange between adjacent silicon-oxygen backbone chain elastomers of the polymer network such that dynamic crosslinks formed between the adjacent silicon-oxygen backbone chain elastomers create a three-dimensional crosslinked polymer network.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - reference to related applications:

[0002] This application claims the priority of U.S. Provisional Application No. 63 / 514,804, filed on July 21, 2023, the entire disclosure of which is incorporated herein by reference.

[0003] Technical Field:

[0004] The present invention relates to a polymer composition having a covalent bond network that can be altered by thermally - activated bond exchanges that form dynamic cross - links. This polymer composition can be reformed by reheating and thus can be re - processed.

Background Art

[0005] Background Art:

[0006] Silicone occupies a large part of the polymer market. The annual production volume in China is about 370,000 tons, and in the world market, the compound annual growth rate (CAGR) from 2019 to 2025 is expected to be 6.1% and reach 2.01 billion US dollars in 2025. Silicone rubber is widely used in general consumer goods and food - contact products because it is superior in tensile strength, thermal stability, and food - contact safety compared to elastomers such as thermoplastic polyurethane (TPU).

[0007] Due to the enormous production volume, large amounts of silicone scrap and waste are generated during the manufacturing process or by the end user. Commercially available silicones cannot be reprocessed due to their thermosetting properties, negatively impacting both production costs and the environment. Currently, the scrap rate due to demolding during manufacturing reaches up to 5%, resulting in an annual loss of 4 to 11 million RMB. The current cost of recycling silicone is 4 to 7 RMB per kilogram, but the development of reprocessable materials such as silicone would be a solution to save production costs, as well as a sustainable solution by saving recycling equipment and resources.

[0008] Conventional methods for reprocessing silicone scrap and waste include either physical decomposition, chemical decomposition, or a combination of both. These include: 1) Mechanically crushing fillers to use as reinforcing materials for composite materials; 2) Downcycling of polydimethylsiloxane (PDMS) into industrial lubricants by depolymerization, developed by Dow Corning (WO2014130948A1); 3) A hydrothermal method for reforming silicone rubber with significantly inferior mechanical properties.

[0009] These low-value-added processes incur extra costs and time in production, are unsustainable, and fail to leverage the strengths of silicone rubber in high-value-added applications.

[0010] Commercially available thermoplastic silicone elastomers include TPSiV, a thermoplastic silicone vulcanized product sold by DuPont. This product is formed by dispersing cross-linked silicone rubber (a vulcanized silicone module containing PDMS) in the thermoplastic continuous phase of thermoplastic polyurethane (TPU) using a platinum hydrosilylation catalyst. This composite material is said to be reprocessable by melting and reshaping. In most cases, the silicone content is less than 50% w / w, and anhydrous conditions are required in the manufacturing process to obtain high-quality TPSiV with high tensile strength. Furthermore, because TPSiV may contain amines or amides in the TPU composite material, it cannot be used in food contact applications.

[0011] For high-value-added applications, there is a need for a new class of polymer elastomers using a silicon-oxygen backbone that can be thermally reprocessed at temperatures beyond the application's required range, while maintaining the advantages of commercially available silicones such as high tensile strength, thermal stability, and food contact safety. This invention addresses this need. [Overview of the project]

[0012] Summary of the invention:

[0013] The present invention provides a novel polymer system based on a silicon-oxygen backbone elastomer that facilitates a change in the material's topology through a thermally activated bond exchange reaction. At their reprocessable temperatures, the polymer system of the present invention flows as a viscoelastic liquid, while at low temperatures, the bond exchange reaction is immeasurably slow, causing the polymer system of the present invention to behave as a thermosetting elastomer.

[0014] To achieve material properties similar to commercially available silicone rubber, namely high tensile strength, thermal stability, and food contact safety, the present invention includes the following: 1) Adjustment to high tensile strength is possible by selecting different chain lengths and branching of the PDMS polymer for the polymer network of the present invention; 2) The optimal reprocessing temperature can be selected by developing and selecting new crosslinking agents for the PDMS-based polymer network; 3) Suitability for food contact is ensured by a high silicon-oxygen polymer content and avoiding the use of TPU during compounding.

[0015] The present invention provides polysiloxane-based polymers having reversible crosslinking by using at least one dynamic bond activator that promotes Si-O bonding between adjacent silicon-oxygen backbone chain elastomers within the polymer network. These polymers are designed to be reversible crosslinking and decrosslinking processes and to be reprocessable.

[0016] In one embodiment, the present invention provides a polymer composition having a covalent network that changes upon thermally activated bond exchange to form dynamic crosslinks. The polymer composition is formed from silicon-oxygen backbone chain elastomers that form the polymer network. Non-aggregating fillers are dispersed and bonded within the polymer network. A catalyst facilitates the condensation reaction. A crosslinking agent is used for crosslinking and may be one or more silanes containing one or more methoxy or ethoxy groups.

[0017] At least one dynamic bond activator promotes Si-O bond exchange between adjacent silicon-oxygen backbone elastomers in the polymer network, such that the dynamic crosslinks formed between adjacent silicon-oxygen backbone elastomers form a three-dimensional crosslinked polymer network.

[0018] In the bulk form, the polymer composition has the properties of a thermosetting polymer under ambient conditions and can be reformed as a viscoelastic liquid at temperatures above about 170°C. In some embodiments, at least 60% of the tensile strength at ambient conditions and at least 70% of the elongation at break at ambient conditions are retained.

[0019] On one side, The polymer composition is Silicon-oxygen backbone chain elastomer Based on this, the silicon-oxygen backbone chain elastomer is Trimethylsilyl-terminated polydimethylsiloxane and silanol-terminated polydimethylsiloxane Includes .

[0020] On one side, the silicon-oxygen backbone chain elastomer has a molecular weight of 5,970 - 139,000 g / mol, At a temperature of 25°C and a pressure of 1 atm a viscosity of 100 - 150,000 cSt, and is present in the composition in an amount of 49.6 - 65.6% by weight.

[0021] On one side, the filler Hexamethyldisilazane-treated silica, contains fumed silica, calcium carbonate, or zinc oxide in an amount of 24.9 - 36.9% by weight.

[0022] On one side, the at least one dynamic bond activator is an ionic salt 、 selected from phosphonium salts , or potassium trimethylsilanolate and has a content of 0.09 - 2.5% by weight.

[0023] On one side, the dynamic bond activator is tetrabutylphosphonium hydroxide.

[0024] On one side, the at least one catalyst contains dibutyltin dilaurate or dibutyltin dioctoate in an amount of 0.12 - 2.3% by weight.

[0025] On one side, the crosslinking agent is a silane having an ethoxy group or a silane having a methoxy group, and the amount thereof is 2.7 to 25.0% by weight.

[0026] On one side, the crosslinking agent is selected from one or more of 1,2-bis(triethoxysilyl)ethane, poly(dimethoxysiloxane), poly(diethoxysiloxane), and tetraethyl silicate.

[0027] The present invention further provides a method for producing a polymer composition. The first silicon-oxygen backbone chain elastomer forms a first mixture in combination with a filler and a crosslinking agent. The second silicon-oxygen backbone chain elastomer is combined with a filler and a catalyst to form a second mixture. The first mixture and the second mixture are combined to form a third mixture, where the first mixture and the second mixture are combined in a weight ratio of 1.1:1 to 8.3:1. The third mixture is combined with at least one dynamic bond activator to form a fourth mixture, which is cured to form a polymer composition. In an optional additional heating step, the solvent can be removed in a vacuum at a temperature of 50 to 80°C.

Brief Description of the Drawings

[0028] Brief Description of the Drawings:

[0029] Figure 1 schematically shows the mechanism of polymer reprocessability.

[0030] Figure 2 shows the reactions involved in the formation of the polymer composition of the present invention.

Modes for Carrying Out the Invention

[0031] Details of the Invention:

[0032] As used herein, the terms “ambient” or “ambient conditions” refer to conditions of 25°C and 1 atmosphere. Unless otherwise specified, all parameters and data described herein were measured under the above ambient conditions.

[0033] Silicon-oxygen backbone elastomers such as polysiloxanes have repeating units of siloxane (-Si-O-) bonds. These polymers possess excellent thermal stability, chemical resistance, and flexibility, making them suitable for a wide range of applications. By incorporating Si-O bonds between adjacent main chains, various mechanical properties can be improved without sacrificing the polymer's ability to reshape or rework.

[0034] The reprocessability of these polymers is particularly useful in reducing waste and promoting sustainability. By breaking and reforming crosslinks, the materials can be repeatedly processed, molded, and reformatted without significant degradation of their properties. This reprocessability expands the possibilities for efficient reuse of materials and reduces the need to manufacture new polymers.

[0035] The polymer composition is formed from silicon-oxygen backbone chain elastomers that form a polymer network. In one aspect, the silicon-oxygen backbone chain elastomers have a molecular weight of 5,970 to 139,000 g / mol, a viscosity of 100 to 150,000 cSt, and are present in the composition in an amount of 49.6 to 65.6% by weight. In particular, these may be one or more trimethylsilyl-terminated polydimethylsiloxanes (PDMS) and silanol-terminated polydimethylsiloxanes (PDMS).

[0036] Non-aggregating fillers are dispersed and bound within the polymer network. On one side, the fillers contain fumed silica, calcium carbonate, or zinc oxide in an amount of 24.9 to 36.9% by weight.

[0037] The catalyst promotes the condensation reaction and contains dibutyltin dilaurate or dibutyltin dioctoate in an amount of 0.12 to 2.3% by weight. The crosslinking agent is used for crosslinking and may be one or more silanes containing one or more methoxy or ethoxy groups. In one aspect, the crosslinking agent is a silane having an ethoxy group or a silane having a methoxy group, in an amount of 2.7 to 25.0% by weight. Examples of suitable crosslinking agents include one or more of 1,2-bis(triethoxysilyl)ethane, poly(dimethoxysiloxane), poly(diethoxysiloxane), and tetraethyl silicate.

[0038] This invention utilizes a dynamic activator to promote Si-O bonding between adjacent silicon-oxygen backbone elastomers in a polymer network. These bonds can take the form of silyl ether groups, which can be tuned to achieve specific properties or optimize reprocessing. The ability to reversibly cleave and reform crosslinks between adjacent Si-O backbone elastomers forms a polymer system that flows as a viscoelastic liquid at high temperatures, but at low temperatures, the bond exchange reaction is immeasurably slow, causing the polymer system to behave as a thermosetting elastomer. This phenomenon is illustrated in Figure 1. As a result, a reprocessable polysiloxane-based polymer with reversible crosslinking is formed, allowing the polymer to be processed and reformatted without significantly impairing its inherent properties. As a result of the dynamic crosslinking between adjacent Si-O backbone elastomers, a three-dimensional crosslinked polymer network is formed that is modifiable under external stimuli such as heat, while exhibiting increased strength and elasticity.

[0039] As used herein, the term “dynamic linkage activator” refers to any material that, when incorporated into a polymer network, can facilitate reversible linkage or crosslinking between polymer chains that can be cleaved and reformed in response to changes in temperature, pH, or the presence of certain chemicals. Dynamic linkage enables polymers to exhibit self-healing properties, adaptability, and enhanced mechanical performance.

[0040] Dynamic bonding types include not only reversible covalent bonds, but also non-covalent interactions such as hydrogen bonds, ionic interactions, and metal-ligand coordination.

[0041] Dynamic bond activators can not only enable polymers to adapt to environmental changes and mechanical stress, but they may also help polymers self-repair after damage. That is, after an activation event, the polymer often regains its structural integrity and mechanical properties with minimal external intervention.

[0042] In this invention, the dynamic bond activator can promote Si-O bonding between adjacent silicon-oxygen backbone chain elastomers in the polymer network. These bonds can take the form of silyl ether groups, which can be tuned to achieve specific properties or optimize polymer reprocessing. The ability to reversibly cleave and reform crosslinks between adjacent Si-O backbone chain elastomers forms a polymer system that flows as a viscoelastic liquid at high temperatures, but at low temperatures, the bond exchange reaction is immeasurably slow, causing the polymer system to behave as a thermosetting elastomer. This phenomenon is shown in Figure 1. As a result, a reprocessable polysiloxane-based polymer with reversible crosslinking is formed, allowing the polymer to be processed and reformatted without significantly impairing its inherent properties.

[0043] In one aspect, at least one dynamic bond activator may be an ionic salt. Examples of such ionic salts include ammonium salts or phosphonium salts. Amounts on the order of approximately 0.09 to 2.5 wt% may be used. A specific example of a dynamic bond activator is tetrabutylphosphonium hydroxide. When tetrabutylphosphonium hydroxide is used as a dynamic bond activator, the Si-O bond formed by exchange between adjacent silicon-oxygen backbone chain elastomers is a silyl ether. Another specific example of a dynamic bond activator is potassium trimethylsilanolate. Silyl ether exchange between different siloxane chains forms reversible crosslinks between different backbone polymer chains, creating a three-dimensional network. The resulting network structure provides the material with mechanical strength and stability.

[0044] Figure 2 shows the reactions involved in the formation of the polymer composition. Polysiloxanes containing crosslinking agents and fillers undergo condensation reactions in the presence of a catalyst. A dynamic bond activator (in this case, tetrabutylphosphonium hydroxide) induces silyl ether exchange between different siloxane chains. Figure 2 shows the formation and decomposition of bonds that form a three-dimensional network.

[0045] In bulk form, the polymer composition has the properties of a thermosetting polymer under ambient conditions, is reformatable as a viscoelastic liquid at temperatures exceeding approximately 170°C, and simultaneously maintains a tensile strength of at least 60% of its ambient tensile strength and a tensile strength of at least 70% of its ambient elongation at fracture.

[0046] The present invention further provides a method for producing a polymer composition. A first silicon-oxygen backbone elastomer is combined with a filler and a crosslinking agent to form a first mixture. A second silicon-oxygen backbone elastomer is combined with a filler and a catalyst to form a second mixture. The first mixture and the second mixture are combined to form a third mixture, where the first and second mixtures are combined in a weight ratio of 1.1:1 to 8.3:1. The third mixture is combined with at least one dynamic linkage activator to form a fourth mixture, which is cured to form a polymer composition. In an optional additional heating step, the solvent can be removed in a vacuum at a temperature of 50 to 80°C. [Examples]

[0047] Examples:

[0048] Various compositions, including the comparative composition, were prepared and tested. The components and their properties are shown below, followed by the methods for manufacturing the compositions. Finally, an overview of the experiment and the components and properties of the prepared compositions are shown in Tables 1-6.

[0049] Silanol-terminal PDMS

[0050] Polydimethylsiloxane (PDMS) with terminal silanol (SiOH) groups was used to form Si-O backbone chain elastomer components for polymer network formation through condensation of the terminal silanol groups. [Table 1]

[0051] Filler

[0052] Fillers enhance the mechanical strength of polymer compositions, including tensile strength, elongation at break, and tear strength. Fillers include fumed silica and zinc oxide. In contrast to the untreated silica in the examples, hexamethyldisilazane-treated silica is used as a filler to increase hydrophobicity by substituting OH groups on the silica surface, thereby promoting good settling resistance of the filler without the undesirable increase in viscosity of the silicone compound during the manufacturing process.

[0053] Crosslinking agent

[0054] The crosslinking agent helps to form a polymer network with the silanol-terminated PDMS. Silanes having an ethoxy or methoxy group are selected to condense with the silanol-terminated PDMS. The ethoxy or methoxy group is removed as ethanol or methanol during the condensation reaction in the presence of the silanol-terminated PDMS. In the examples, poly(diethoxysiloxane) (containing 40-42% SiO2; abbreviated as PSI-021) and / or 1,2-bis(triethoxysilyl)ethane are used.

[0055] Trimethylsilyl-terminated PDMS

[0056] Polydimethylsiloxane (PDMS) having terminal trimethylsilyl groups is an additive for viscosity modification. These trimethylsilyl-terminated PDMS chains penetrate the condensed and crosslinked PDMS network, providing flexibility to the resulting material.

[0057] [Table 2]

[0058] catalyst

[0059] Dibutyltin dilaurate was used in a condensation system containing silanol-terminated PDMS and its crosslinking agent.

[0060] Dynamic binding activator

[0061] To enable reprocessing, ionic salts such as ammonium salts or phosphonium salts were selected. In these examples, tetrabutylphosphonium hydroxide (40%) was used.

[0062] Manufacturing procedure

[0063] A planetary centrifugal mixer is typically used to mix the compositions of the examples. A crosslinking agent was added to silanol-terminated PDMS and mixed at 2000 rpm for 20 seconds, followed by the addition of hexamethyldisilazane-treated fumed silica at 2000 rpm for 2 minutes to form the first mixture.

[0064] Dibutyltin dilaurate was added to trimethylsilyl-terminated PDMS and mixed at 2000 rpm for 20 seconds. Subsequently, hexamethyldisilazane-treated fumed silica was mixed at 2000 rpm for 2 minutes to form a second mixture.

[0065] The second mixture was added to the first mixture in the weight ratios shown in Tables 3-6 (5 minutes; 2000 rpm) to form the third mixture.

[0066] A dynamic binding activator was added to the third mixture and mixed (5 minutes; 2000 rpm) to form the fourth mixture.

[0067] The fourth mixture was poured into a mold and placed in a temperature and humidity controlled chamber (25°C; 95%RH).

[0068] The resulting cured polymer was then left in a vacuum oven at 60°C for 4 hours as an optional post-curing step.

[0069] mechanical properties

[0070] The samples were cut to standard test specimen size (dumbbell shape) according to ASTM international standards.

[0071] Reprocessing feasibility

[0072] The samples were reprocessed at 170°C for 6 hours under molding conditions. The reprocessed silicone was cut into standard test specimen sizes for measurement of mechanical properties.

[0073] Tables 3, 4, 5, and 6 show the various compositions formed by the examples and their measured mechanical properties.

[0074] It is well known that the mechanical properties of silicone rubber depend on the viscosity and overall solids content of its composition. Viscosity and overall solids content can be optimized by adjusting the ratio of the component amounts of the first and second mixtures. Examples 1-4 formed various compositions with tensile strengths ranging from 1.17 to 5 MPa, as shown in Table 3. These compositions had Shore A hardness in the range of 20 to 50 units. Comparing Examples 1-4 with Example 5, increasing the amount of hexamethyldisilazane-treated fumed silica in the composition increased the overall solids content of the composition, and the tensile strength increased from 4.21 MPa to 5 MPa and 6.03 MPa, respectively.

[0075] High molecular weight silanol-terminated PDMSs, such as DMS-S51 in Table 4, are expected to have more polymer chain entanglement, while low molecular weight silanol-terminated PDMSs, such as DMS-S33, are expected to have higher crosslinking density and density. Compositions containing DMS-S51 are expected to have high elongation at break in the form of flexible rubber, according to common sense in the art. However, this is not the case when comparing Example 1 in Table 3 and Example 6 in Table 4 (the elongation at break in Example 1 is 1178%, compared to 570% in Example 6). Referring to Examples 7, 8, 9, and 10 in Table 5, which use low molecular weight silanol-terminated PDMS (DMS-S33), the elongation at break can be adjusted by adding appropriate amounts of trimethylsilyl-terminated PDMS and crosslinking agents, poly(diethoxysiloxane) (containing 40-42% SiO2; abbreviated as PSI-021) and 1,2-bis(triethoxysilyl)ethane. The trimethylsilyl-terminated PDMS chains penetrate the condensed and crosslinked PDMS network, resulting in flexibility in the resulting material. Comparing Examples 7 and 8 in Table 5 and Examples 13 and 14 in Table 6, the use of 1,2,-bis(triethoxysilyl)ethane as a crosslinking agent resulted in a decrease in elongation at break from 357% to 69.1%. Comparing Examples 7 and 10, using a lower molecular weight (DMS-T21) trimethylsilyl-terminated PDMS than the higher molecular weight (DMS-T31) in Table 2 resulted in a decrease in elongation at break from 357% to 170%.

[0076] Referring to Comparative Examples 16 and 17, the first and second mixtures are combined in a weight ratio of 24:1, but these compositions lack the property to reshape as a viscoelastic liquid at temperatures above approximately 170°C.

[0077] Examples 5 in Table 3, 6 in Table 4, 8 and 9 in Table 5, and 14 and 15 in Table 6 possess the properties of a thermosetting polymer under ambient conditions and can be remolded as a viscoelastic liquid at temperatures exceeding approximately 170°C while maintaining a tensile strength of 60% or less of the ambient tensile strength and 70% or less of the ambient elongation at break. [Table 3] [Table 4] [Table 5] [Table 6] [Industrial applicability]

[0078] Industrial applicability:

[0079] By using a dynamic bond activator that promotes Si-O exchange between adjacent silicon-oxygen backbone chains, the polymer of the present invention can be reformatted and reshaped when exposed to heat. However, under ambient conditions, this polymer exhibits properties typical of thermosetting materials. It has a stable crosslinked structure and maintains its shape and mechanical properties. On the one hand, when heated to temperatures above approximately 170°C, the dynamic bond activator promotes Si-O bond exchange. This process causes the polymer to behave like a viscoelastic liquid, enabling reformatting and reprocessing. Importantly, this reformatting process does not significantly degrade the material's properties. Instead, at least some polymer compositions maintain at least 60% of their tensile strength and 70% of their elongation at break after reformatting compared to their ambient properties. This retention of mechanical properties ensures the material's functionality and reliability after heat treatment. As a result, this polymer can be used in a variety of applications where recyclability and reprocessability are required. These applications include reusable molds and seals, including the creation of molds and seals that may need to be reformatted periodically. This material is safe for food contact and can be used in silicone food storage containers. This polymer also has potential applications in self-healing materials and flexible electronic devices. Because this polymer is biocompatible, can be sterilized and reshaped, it can also be used to manufacture medical devices.

[0080] The above description of the present invention is provided for illustrative and explanatory purposes only. It is not intended to be exhaustive or to limit the invention to the exact form disclosed. Many modifications and variations will be apparent to those skilled in the art.

[0081] The embodiments are selected and described in order to best illustrate the principles and practical applications of the present invention, thereby enabling those skilled in the art to understand the invention in various embodiments and various modifications suitable for specific conceivable applications.

[0082] As used in this book, unless otherwise defined, the terms “substantially,” “substantial,” “approximately,” and “about” are used to describe and explain small variations. When used in relation to an event or situation, these terms may include not only cases where the event or situation occurs exactly, but also cases where it occurs approximately. For example, when used in combination with a numerical value, these terms may include a range of variation of that value of ±10% or less, such as ±5%, ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.1%, ±0.05%, etc.

[0083] In this specification, the singular forms “a,” “an,” and “the” include a plural reference unless the context explicitly indicates otherwise. In the description of some embodiments, a component provided on or above another component (e.g., in physical contact with…) may include cases where the former component is directly above the latter component, as well as cases where one or more intervening components are located between the former and latter components.

[0084] This disclosure has been described and illustrated with reference to specific embodiments thereof, but these descriptions and illustrations are not limiting. Those skilled in the art will understand that various modifications can be made and equivalents can be substituted without departing from the true spirit and scope of this disclosure as defined by the appended claims. The drawings are not necessarily drawn to a fixed scale. Due to manufacturing processes and tolerances, there may be distinctions between artistic renditions in this disclosure and actual apparatus. Other embodiments of this disclosure that are not specifically illustrated may exist. The specification and drawings should be considered illustrative, not limiting. Modifications can be made to suit the purpose, spirit and scope of this disclosure with respect to specific circumstances, materials, composition of substances, methods, or processes. All such modifications are intended to be included within the scope of the appended claims. The methods disclosed herein have been described with reference to specific operations performed in a specific order, but it will be understood that these operations can be combined, subdivided, or rearranged to form equivalent methods without departing from the teachings of this disclosure. Thus, the order and grouping of operations are not limiting unless specifically shown herein.

Claims

1. A polymer composition having a covalent network that changes through thermally activated bond exchange to form dynamic crosslinks, A siloxane-based polymer network based on silicon-oxygen backbone chain elastomers containing trimethylsilyl-terminated polydimethylsiloxanes and silanol-terminated polydimethylsiloxanes; A non-aggregating filler dispersed within the polymer network, comprising hexamethyldisilazane-treated silica, fumed silica, calcium carbonate, or zinc oxide in an amount of 24.9 to 36.9% by weight; A catalyst that promotes the condensation reaction; A crosslinking agent selected from one or more silanes containing one or more methoxy or ethoxy groups; A dynamic linkage activator that promotes Si-O bond exchange between adjacent silicon-oxygen backbone chain elastomers in a polymer network, such that dynamic crosslinks formed between adjacent silicon-oxygen backbone chain elastomers form a three-dimensional crosslinked polymer network, comprising 0.09 to 2.5% by weight of an ionic salt selected from tetrabutylphosphonium hydroxide, potassium trimethylsilanolate, or a mixture thereof; Includes, In bulk form, the polymer composition has the properties of a thermosetting polymer under ambient conditions and can be reformatted as a viscoelastic liquid at temperatures exceeding approximately 170°C.

2. The polymer composition according to claim 1, wherein the silicon-oxygen backbone chain elastomer has a molecular weight of 5,970 to 139,000 g / mol, a viscosity of 100 to 150,000 cSt, and is present in the composition in an amount of 49.6 to 65.6% by weight.

3. The polymer composition according to claim 1, wherein the at least one dynamic binding activator is tetrabutylphosphonium hydroxide.

4. The polymer composition according to claim 1, wherein the at least one catalyst contains dibutyltin dilaurate or dibutyltin dioctoate in an amount of 0.12 to 2.3% by weight.

5. The polymer composition according to claim 1, wherein the crosslinking agent contains 2.7 to 25.0% by weight of a silane having an ethoxy group and a silane having a methoxy group.

6. The polymer composition according to claim 5, wherein the crosslinking agent is selected from one or more of 1,2-bis(triethoxysilyl)ethane, poly(dimethoxysiloxane), poly(diethoxysiloxane), and tetraethyl silicate.

7. The polymer composition according to claim 1, wherein the remolded polymer composition retains at least 60% of the tensile strength under ambient conditions and at least 70% of the elongation at break under ambient conditions of the same polymer composition before remolding.

8. A method for producing the polymer composition described in claim 1, The first silicon-oxygen skeleton chain elastomer is combined with a filler and a crosslinking agent to form a first mixture. The second silicon-oxygen backbone chain elastomer is combined with a filler and a catalyst to form a second mixture; The first mixture and the second mixture are combined to form a third mixture, wherein the first mixture and the second mixture are combined in a weight ratio of 1.1:1 to 8.3:1; The third mixture is combined with at least one dynamic binding activator to form a fourth mixture; The fourth mixture is cured to form a polymer composition; A manufacturing method that includes this.

9. The method according to claim 8, further comprising heating the polymer composition in a vacuum at a temperature of 50 to 80°C.

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