Elastic silica gel, shoulder strap and preparation process

Abstract

The invention relates to the technical field of silica gel shoulder straps, and discloses an elastic silica gel, a shoulder strap and a preparation process, the elastic silica gel is obtained by performing ball milling modification on filler such as alumina powder by using siloxane polyurethane, and then mixing the modified filler with vinyl silicone oil, hydrogen-containing silicone oil, a catalyst, a rheological additive and the like. The shoulder strap containing the elastic silica gel is composed of a surface basic fabric layer, an elastic silica gel layer and an elastic gauze adjusting layer. The silica gel material is excellent in strength, toughness and elasticity, and the alumina powder is uniformly dispersed in the silicone rubber matrix, so that the heat conduction and heat dissipation performance of the silica gel material is remarkably improved. The shoulder strap is excellent in toughness and elasticity and low in elasticity attenuation. Through the combination of the quick-dry fabric, the dot matrix silica gel and the breathable gauze, the supporting performance, the breathability and the comfort needed by the sports underwear are perfectly balanced, and the high-strength sports requirement is met.

Description

Technical Field

[0001] This invention relates to the field of silicone shoulder strap technology, specifically to an elastic silicone, a shoulder strap, and a manufacturing process. Background Technology

[0002] Silicone rubber is non-toxic, low-irritant, skin-friendly, environmentally friendly, and has excellent flexibility, making it widely used in daily necessities, medical devices, and sealants. To improve the thermal conductivity of silicone rubber and expand its applications in heat-dissipating gels and thermally conductive sealants, fillers such as alumina and boron nitride need to be added.

[0003] Alumina is inexpensive and readily available, and has high thermal conductivity, making it an ideal thermally conductive filler. However, alumina has poor compatibility with silicone rubber. While adding excessive alumina can improve the thermal conductivity of silicone rubber, it will severely affect the strength, flexibility, and other properties of silicone rubber.

[0004] Polyurethane is a common high-molecular polymer material with excellent mechanical strength and toughness. It has important applications in silicone rubber, rubber and plastic materials, and fibers. Combining polyurethane with silicone rubber can produce high-strength and high-toughness composite materials.

[0005] Traditional bra straps are often made of ordinary textiles or silicone rubber, which suffer from poor breathability, stuffiness, and discomfort against the skin. To provide sufficient support, the straps are usually designed to be narrow and have limited elasticity, resulting in excessive pressure per unit area, compressing shoulder muscles and nerves, causing pain, marks, and discomfort. While existing technologies use silicone in bra straps, it is mostly as an external covering or embellishment, failing to innovatively combine it as a core functional layer with adjustable mesh fabrics, and also unable to achieve precise customization of performance through material and process integration. Therefore, developing a silicone composite material for bra straps that combines excellent thermal conductivity, softness and skin-friendliness, and flexible elasticity is crucial. Summary of the Invention

[0006] The technical problem solved by this invention is that silicone has poor thermal conductivity and heat dissipation, while also having good elasticity and tensile properties, making it better suited for use in materials such as shoulder straps.

[0007] The technical solution of this invention: A preparation process for elastic silicone is as follows: (1) Nitrogen gas was introduced into the reaction flask, and tetrahydrofuran, 1,1,3,3-tetramethyldisiloxane, sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, and platinum catalyst were added. After the reaction, petroleum ether was added, and the mixture was stirred and extracted with water. The aqueous phase was collected, heated to evaporate, and cooled to crystallize, yielding the chain extender. The reaction formula is as follows: .

[0008] (2) Nitrogen gas is introduced into the reaction vessel, and dried and dehydrated polyether polyol, isocyanate monomer and dibutyltin dilaurate are added. The mixture is stirred and reacted, and then acetone and chain extender are added. The mixture is cooled and reacted. Acetone is removed by vacuum distillation to obtain siloxane polyurethane.

[0009] (3) Add water, siloxane polyurethane, and thermally conductive filler to the ball mill, disperse by ball milling, dry and remove water, add the material with vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, and rheology modifier to the high-speed dispersant, disperse by shearing, add platinum catalyst and adhesion promoter, disperse by shearing, discharge the material, and obtain elastic silicone.

[0010] Preferably, in (1), the mass ratio of 1,1,3,3-tetramethyldisiloxane, sodium 3-allyloxy-2-hydroxy-1-propanesulfonate and platinum catalyst is 100:(326-358):(1-1.8).

[0011] Preferably, in (1), the reaction temperature is 60-65℃ and the reaction time is 5-8h.

[0012] Preferably, in (2), the molar ratio of polyether polyol, isocyanate monomer, dibutyltin dilaurate, and chain extender is 1:(2.4-2.6):(0.003-0.004):(1.2-1.3).

[0013] Preferably, the temperature during the stirring reaction in (2) is 70-80℃ and the reaction time is 2-3h.

[0014] Preferably, in (2), the temperature during the cooling reaction is 45-50℃ and the reaction time is 1-1.5h.

[0015] Preferably, the polyether polyol in (2) includes polyethylene glycol and polytetrahydrofuran ether diol.

[0016] Preferably, the isocyanate monomer in (2) includes isophorone diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0017] Preferably, in (3), the mass ratio of vinyl silicone oil, hydrogen-containing silicone oil, platinum catalyst, thermally conductive filler, siloxane polyurethane, inhibitor, adhesion promoter and rheology modifier is 100:(1-5):(0.5-2):(30-80):(30-60):(0.04-0.07):(0.5-3):(1-4).

[0018] Preferably, in (3), the ball milling speed is 200-500 r / min and the ball milling time is 2-4 h.

[0019] Preferably, the inhibitor in (3) is 1-ethynylcyclohexanol.

[0020] Preferably, the adhesion promoter in (3) is vinyltrimethoxysilane.

[0021] Preferably, the rheology modifier in (3) is fumed silica.

[0022] Preferably, the thermally conductive filler in (3) includes alumina, boron nitride or diamond.

[0023] The present invention also provides the following technical solution: a shoulder strap containing elastic silicone, the shoulder strap having a multi-layer structure including a surface base fabric layer, an elastic silicone layer, and an elastic mesh adjustment layer.

[0024] Preferably, the surface base fabric can be flexibly selected from a variety of textile materials according to the appearance, feel and durability required by the final product. The surface base fabric layer includes any one or more blended fabrics of nylon, polyester, cotton, modal and silk.

[0025] Preferably, the elastic silicone layer serves as the core interlayer, thermally conductive and comfortable functional area, and structural bonding point. By printing silicone of different thicknesses, the softness and thermal conductivity of the final product can be balanced.

[0026] Preferably, the elastic mesh adjustment layer is bonded to the elastic silicone layer, using elastic mesh adjustment layers of different specifications (such as yarn type, mesh count, and weaving method). With this innovative "silicone layer + mesh layer" structural design, the support and softness of the shoulder straps can be precisely designed and adjusted by controlling the strength, hardness, width, and thickness of the silicone and applying mesh of different elastic materials. The tensile strength, elastic elongation, width, and thickness of the final shoulder strap product can be customized to meet the size standards and comfort requirements of different markets worldwide.

[0027] Preferred manufacturing process for shoulder straps containing elastic silicone: S1. Cut the fabric into strips and bond the cut edges with an ultrasonic bonding machine or weave them with a cylindrical weaving machine to form an independent tubular structure.

[0028] S2. Based on the viscosity of the silicone and the required adhesive layer thickness, select a 40-80 mesh screen. The silicone is precisely screen-printed onto the bonding area of ​​the base tube through the screen to form a uniform adhesive layer. The pre-cut elastic mesh layer is then precisely laid and aligned. Utilizing the thixotropic and initial tack properties of the silicone itself, the mesh layer is temporarily and stably adsorbed onto the adhesive layer. It is then dried and cured at a specific temperature and time.

[0029] S3. Place the laminated, dried, and cured materials in a hot press and heat-press them together under specific temperature, pressure, and time conditions. Trim the rough edges to obtain a shoulder strap containing elastic silicone. The prepared shoulder strap exhibits excellent toughness and elasticity; preferably, the elasticity decay is controlled within 12-18%. The shoulder strap has good water resistance; preferably, the elongation retention rate after 20 washes is >97%, indicating that the product can still maintain excellent elastic deformation ability after washing, which is the mechanical basis for the "non-restrictive" comfort. The composite strength is extremely high; preferably, the strength retention rate after 50 washes is >92%, with no delamination.

[0030] The beneficial technical effects of this invention are as follows: Siloxane polyurethane is ball-milled to modify fillers such as alumina powder, and then mixed with vinyl silicone oil, hydrogen-containing silicone oil, catalyst, rheology modifier, etc., to obtain elastic silicone. The molecular chain of siloxane polyurethane contains a large number of siloxane groups, exhibiting excellent compatibility with silicone rubber. Polyurethane has high strength and good toughness; when uniformly compounded with polysiloxane silicone rubber, the silicone material possesses both good tensile strength and elongation at break, exhibiting excellent strength, toughness, and elasticity.

[0031] The siloxane polyurethane of the present invention contains a large number of sulfonate groups, which interact with the surface of alumina powder during ball milling, thus acting as a dispersant to improve the agglomeration of alumina powder and enhance the compatibility between alumina powder and polysiloxane silicone rubber, reducing the impact on the mechanical properties of silicone materials. The alumina powder is uniformly dispersed in the silicone rubber matrix, significantly improving the thermal conductivity and heat dissipation performance of silicone materials.

[0032] This invention features shoulder straps with an elastic silicone layer that offer both ultra-softness and active heat conduction, quickly dissipating heat and moisture. The formula can be adjusted to adjust hardness to meet different market and size requirements, fundamentally improving dryness, softness, and comfort. The manufacturing process fully utilizes the adhesive properties of silicone, enhancing the bonding strength at the shoulder strap base tube's adhesive joint for durability and resistance to detachment. Ultrasonic welding replaces traditional stitching, resulting in needle-free, skin-friendly, high-strength, waterproof, and cleaner-looking straps. The shoulder straps exhibit excellent toughness and elasticity with minimal elasticity loss. They are strong and stable, effectively absorbing shock and preventing shifting during exercise; ultra-breathable for rapid sweat wicking; non-abrasive with a seamless, traceless design; and washable without deformation after repeated washing. Through a combination of quick-drying fabric, dot matrix silicone, and breathable mesh, the support, breathability, and comfort required for sports bras are perfectly balanced to meet the demands of high-intensity exercise. The shoulder straps have good water resistance and high elongation retention after washing, indicating that the product can still maintain excellent elastic deformation ability after washing. This is the mechanical basis for the "non-restrictive" comfort. There is no delamination. The silicone material itself is resistant to aging and still maintains a skin-friendly feel after washing, without hardening or embrittlement, fundamentally eliminating the problem of skin constriction after washing. Attached Figure Description

[0033] Figure 1This is a schematic diagram of a shoulder strap containing elastic silicone.

[0034] Figure 2 These are actual photos of shoulder straps containing elastic silicone. Detailed Implementation

[0035] The technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Example 1: (1) Nitrogen gas was introduced into the reaction flask, and 3L of tetrahydrofuran, 50g of 1,1,3,3-tetramethyldisiloxane, 163g of sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, and 1.8g of platinum catalyst (Castel catalyst, platinum content 1000ppm, the same below) were added. The mixture was heated to 65°C, refluxed for 5h, petroleum ether was added, and the mixture was stirred and extracted with water. The aqueous phase was collected, heated to evaporate, and cooled to crystallize, thus obtaining the chain extender.

[0037] (2) Nitrogen gas was introduced into the reaction vessel, and 1 mol of dried polyethylene glycol 2000, 2.4 mol of toluene-2,4-diisocyanate and 3.6 mmol of dibutyltin dilaurate were added. The mixture was heated to 80°C and stirred for 2 h. Then 500 mL of acetone and 1.2 mol of chain extender were added, the temperature was lowered to 45°C and the mixture was reacted for 1.5 h. The acetone was removed by vacuum distillation to obtain siloxane polyurethane.

[0038] (3) Add 2L of water, 0.6kg of siloxane polyurethane, and 0.6kg of alumina powder (average particle size 3μm, the same below) to the ball mill. Control the rotation speed at 300r / min and ball mill for 2h. Dry and remove water. Add the material to the high-speed dispersant along with 2kg of vinyl silicone oil (model Shenzhen Tianqi Xinxin Material SK-SOV04, the same below), 64g of hydrogen-containing silicone oil (hydrogen content 1.55), 1g of 1-ethynylcyclohexanol, and 80g of fumed silica. Shear and disperse. Then add 23g of platinum catalyst (Castel catalyst, platinum content 1000ppm, the same below) and 42g of vinyltrimethoxysilane. Shear and disperse. Discharge to obtain elastic silicone.

[0039] Example 2: (1) Nitrogen gas was introduced into the reaction flask, and 4L of tetrahydrofuran, 50g of 1,1,3,3-tetramethyldisiloxane, 179g of sodium 3-allyloxy-2-hydroxy-1-propanesulfonate and 1g of platinum catalyst were added. The mixture was heated to 60°C and refluxed for 8 hours. Petroleum ether was added, and the mixture was stirred and extracted with water. The aqueous phase was collected, heated to evaporate, and cooled to crystallize, thus obtaining the chain extender.

[0040] (2) Nitrogen gas was introduced into the reaction vessel, and 1 mol of dried polytetrahydrofuran ether diol 2000, 2.4 mol of isophorone diisocyanate and 4 mmol of dibutyltin dilaurate were added. The mixture was heated to 70°C and stirred for 3 h. Then 500 mL of acetone and 1.2 mol of chain extender were added, the temperature was lowered to 45°C, and the mixture was reacted for 1.5 h. The acetone was removed by vacuum distillation to obtain siloxane polyurethane.

[0041] (3) Add 3L of water, 0.9kg of siloxane polyurethane and 1.2kg of alumina powder to the ball mill, control the speed to 500r / min, ball mill and disperse for 2h, dry and remove water, add the material with 2kg of vinyl silicone oil, 100g of hydrogen-containing silicone oil, 1.4g of 1-ethynylcyclohexanol and 20g of fumed silica to the high-speed dispersant, shear and disperse, then add 40g of platinum catalyst and 10g of vinyltrimethoxysilane, shear and disperse, discharge the material to obtain elastic silicone.

[0042] Example 3: (1) Nitrogen gas was introduced into the reaction vessel, and 1 mol of dried and dehydrated polyethylene glycol 2000, 2.6 mol of diphenylmethane-4,4-diisocyanate and 3 mmol of dibutyltin dilaurate were added. The mixture was heated to 80°C and stirred for 2 h. Then 600 mL of acetone and 1.3 mol of chain extender (prepared according to the method of Example 1) were added. The mixture was cooled to 50°C and reacted for 1 h. The acetone was removed by vacuum distillation to obtain siloxane polyurethane.

[0043] (2) Add 3L of water, 1.2kg of siloxane polyurethane and 1.6kg of alumina powder to the ball mill, control the speed at 200r / min, ball mill and disperse for 4h, dry and remove water, add the material with 2kg of vinyl silicone oil, 20g of hydrogen-containing silicone oil, 0.8g of 1-ethynylcyclohexanol and 70g of fumed silica to the high-speed dispersant, shear and disperse, then add 10g of platinum catalyst and 60g of vinyltrimethoxysilane, shear and disperse, discharge the material to obtain elastic silicone.

[0044] Comparative Example 1: (1) Add 2L of water and 0.6kg of alumina powder to a ball mill, control the rotation speed to 300r / min, ball mill and disperse for 2h, dry and remove water, add the material with 2kg of vinyl silicone oil, 64g of hydrogen-containing silicone oil, 1g of 1-ethynylcyclohexanol and 80g of fumed silica to a high-speed dispersant, shear disperse, add 23g of platinum catalyst and 42g of vinyltrimethoxysilane, shear disperse, discharge the material, and obtain elastic silicone.

[0045] Comparative Example 2: (1) Nitrogen gas was introduced into the reaction vessel, and 1 mol of dried and dehydrated polyethylene glycol 2000, 2.4 mol of toluene-2,4-diisocyanate and 3.6 mmol of dibutyltin dilaurate were added. The mixture was heated to 80°C and stirred for 2 h. Then 500 mL of acetone and 1.2 mol of 1,3-bis(4-hydroxybutyl)-1,1,3,3-tetramethyldisiloxane (CAS No. 5931-17-9) were added. The mixture was cooled to 45°C and reacted for 1.5 h. The acetone was removed by vacuum distillation to obtain siloxane polyurethane.

[0046] (2) Add 2L of water, 0.6kg of siloxane polyurethane and 0.6kg of alumina powder to the ball mill, control the speed to 300r / min, ball mill and disperse for 2h, dry and remove water, add the material with 2kg of vinyl silicone oil, 64g of hydrogen-containing silicone oil, 1g of 1-ethynylcyclohexanol and 80g of fumed silica to the high-speed dispersant, shear and disperse, then add 23g of platinum catalyst and 42g of vinyltrimethoxysilane, shear and disperse, discharge the material to obtain silicone material.

[0047] Comparative Example 3: (1) Nitrogen gas was introduced into the reactor, and 1 mol of dried and dehydrated polyethylene glycol 2000, 2.4 mol of toluene-2,4-diisocyanate, and 3.6 mmol of dibutyltin dilaurate were added. The mixture was heated to 80°C and stirred for 2 h. Then, 500 mL of acetone and 1.2 mol of sodium 1,2-dihydroxy-3-propanesulfonate (structural formula: The temperature was lowered to 45°C, and the reaction was carried out for 1.5 hours. Acetone was removed by vacuum distillation to obtain sulfonate polyurethane.

[0048] (2) Add 2L of water, 0.6kg of sulfonate polyurethane and 0.6kg of alumina powder to the ball mill, control the speed to 300r / min, ball mill and disperse for 2h, dry and remove water, add the material with 2kg of vinyl silicone oil, 64g of hydrogen-containing silicone oil, 1g of 1-ethynylcyclohexanol and 80g of fumed silica to the high-speed dispersant, shear and disperse, then add 23g of platinum catalyst and 42g of vinyltrimethoxysilane, shear and disperse, discharge the material to obtain silicone material.

[0049] Comparative Example 4: (1) Add 4L of ethanol, 200mL of water, and 20g of silane coupling agent KH550 to the reaction flask, stir, add 0.5kg of alumina powder, heat to 75℃, stir, reflux and cool for 4h, filter, wash with ethanol, and dry to obtain modified alumina.

[0050] (2) 0.6 kg of modified alumina powder, 2 kg of vinyl silicone oil, 64 g of hydrogen-containing silicone oil, 1 g of 1-ethynylcyclohexanol and 80 g of fumed silica were added to a high-speed dispersant and sheared and dispersed. Then 23 g of platinum catalyst and 42 g of vinyltrimethoxysilane were added and sheared and dispersed. The material was discharged to obtain the silicone material.

[0051] The silicone material was placed at 25°C for 24 hours and then at 130°C for 5 minutes to prepare a test sample for performance testing.

[0052] Table 1 Properties of silicone

[0053] The tensile strength, elongation at break, thermal conductivity, mechanical strength, toughness, elasticity, and heat dissipation performance of the silicone material in Comparative Example 1 were poor. This was mainly because the added alumina powder had poor compatibility with silicone rubber and poor dispersion in silicone, making it prone to agglomeration, which affected the mechanical properties and heat dissipation performance of the silicone material.

[0054] In Examples 1-3, siloxane polyurethane was added to the silicone materials. Its molecular chain contains a large number of siloxane groups, exhibiting excellent compatibility with silicone rubber. Polyurethane possesses advantages such as high strength and good toughness. After uniform compounding with polysiloxane silicone rubber, the silicone material exhibits both good tensile strength and elongation at break, demonstrating excellent strength, toughness, and elasticity. Furthermore, the siloxane polyurethane contains a large number of sulfonate groups, which interact with the surface of alumina powder during ball milling, acting as a dispersant to improve alumina powder agglomeration and enhance the compatibility between alumina powder and polysiloxane silicone rubber, reducing the impact on the mechanical properties of the silicone material. The uniform dispersion of alumina powder within the silicone rubber matrix significantly improves the thermal conductivity and heat dissipation performance of the silicone material.

[0055] The 1,3-bis(4-hydroxybutyl)-1,1,3,3-tetramethyldisiloxane of Comparative Example 2 and the prepared silicone polyurethane do not contain sulfonic acid groups, making it difficult to act as a dispersant, unable to improve the agglomeration of alumina powder, and difficult to improve the compatibility between alumina powder and polysiloxane alkyl silicone rubber. The tensile strength, elongation at break and thermal conductivity of the silicone material are lower than those of Example 1.

[0056] Sodium 1,2-dihydroxy-3-propanesulfonate and the prepared sulfonate polyurethane in Comparative Example 3 do not contain siloxane groups, resulting in poor compatibility between the polyurethane, alumina powder and silicone rubber. The tensile strength, elongation at break and thermal conductivity of the silicone material are lower than those in Example 1.

[0057] Comparative Example 4 used conventional silane coupling agent KH550 to modify alumina without adding polyurethane. The tensile strength and elongation at break of the silicone material were significantly lower than those in Example 1.

[0058] The present invention also provides the following embodiments.

[0059] Example 4: S1. Cut the polyester fabric into strips and bond the cut edges with an ultrasonic bonding machine to form an independent tubular structure.

[0060] S2. Using a 60-mesh screen, elastic silicone (prepared in Example 1) is precisely screen-printed onto the bonding area of ​​the base tube to form a uniform adhesive layer. The pre-cut elastic mesh layer is then precisely laid and aligned. Utilizing the thixotropic and initial tack properties of the silicone itself, the mesh layer is temporarily and stably adsorbed onto the adhesive layer. The mesh layer is then dried and cured at 130°C for 5 minutes.

[0061] S3. Place the stacked and dried materials in a hot press and press them together at 160°C and 1MPa pressure for 18 seconds. Trim the rough edges to obtain a shoulder strap containing elastic silicone.

[0062] Example 5: S1. Cut the nylon fabric into strips and bond the cut edges with an ultrasonic bonding machine to form an independent tubular structure.

[0063] S2. Using a 60-mesh screen, elastic silicone (prepared in Example 1) is precisely screen-printed onto the bonding area of ​​the base tube to form a uniform adhesive layer. The pre-cut elastic mesh layer is then precisely laid and aligned. Utilizing the thixotropic and initial tack properties of the silicone itself, the mesh layer is temporarily and stably adsorbed onto the adhesive layer. The mesh layer is then dried and cured at 120°C for 10 minutes.

[0064] S3. Place the stacked and dried materials in a hot press and press them together at 160°C and 0.7MPa pressure for 18 seconds. Trim the rough edges to obtain a shoulder strap containing elastic silicone.

[0065] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An elastic silicone rubber, characterized in that, The elastic silicone comprises the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, platinum catalyst, thermally conductive filler, siloxane polyurethane, inhibitor, adhesion promoter, and rheology modifier in a mass ratio of 100:(1-5):(0.5-2):(30-80):(30-60):(0.04-0.07):(0.5-3):(1-4); The siloxane polyurethane is prepared by the following process: Nitrogen gas was introduced into the reactor, and dried and dehydrated polyether polyol, isocyanate monomer, and dibutyltin dilaurate were added. The mixture was stirred and reacted. Then, acetone and chain extender were added, and the mixture was cooled and reacted. The acetone was removed by vacuum distillation to obtain siloxane polyurethane. The structural formula of the chain extender is: .

2. The elastic silicone according to claim 1, characterized in that, The inhibitor is 1-ethynylcyclohexanol, the adhesion promoter is vinyltrimethoxysilane, and the rheology modifier is fumed silica.

3. The elastic silicone according to claim 1, characterized in that, The thermally conductive filler includes alumina, boron nitride, or diamond.

4. The elastic silicone according to claim 1, characterized in that, The temperature during the stirring reaction is 70-80℃, and the reaction time is 2-3 hours; the temperature during the cooling reaction is 45-50℃, and the reaction time is 1-1.5 hours.

5. The elastic silicone according to claim 1, characterized in that, The molar ratio of the polyether polyol, isocyanate monomer, dibutyltin dilaurate, and chain extender is 1:(2.4-2.6):(0.003-0.004):(1.2-1.3).

6. The elastic silicone according to claim 4, characterized in that, The polyether polyol is polyethylene glycol or polytetrahydrofuran ether diol; the isocyanate monomer is isophorone diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate.

7. The elastic silicone according to claim 1, characterized in that, The chain extender is prepared as follows: nitrogen gas is introduced into a reaction flask, and tetrahydrofuran, 1,1,3,3-tetramethyldisiloxane in a mass ratio of 100:(326-358):(1-1.8), sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, and platinum catalyst are added. The mixture is heated to 60-65°C, refluxed for 5-8 hours, petroleum ether is added, and the mixture is stirred and extracted with water. The aqueous phase is collected, heated to evaporate, and cooled to crystallize, thus obtaining the chain extender.

8. A process for preparing elastic silicone as described in any one of claims 1-7, characterized in that, The preparation process is as follows: water, siloxane polyurethane, and thermally conductive filler are added to a ball mill, the rotation speed is controlled at 200-500 r / min, the ball mill is dispersed for 2-4 hours, the material is dried to remove water, the material is added to a high-speed dispersant along with vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, and rheology modifier, and sheared and dispersed. Platinum catalyst and adhesion promoter are added last, sheared and dispersed, and the material is discharged to obtain elastic silicone.

9. A shoulder strap containing the elastic silicone according to any one of claims 1-7, characterized in that, The shoulder strap has a multi-layer structure, including a surface base fabric layer, an elastic silicone layer, and an elastic mesh adjustment layer; the surface base fabric layer includes any one or more blended fabrics of nylon, polyester, cotton, modal, and silk.

10. A manufacturing process for a shoulder strap containing elastic silicone as described in claim 9, characterized in that, The preparation process includes: S1. Cut the fabric into strips and bond the cut edges with an ultrasonic bonding machine or weave them with a cylindrical weaving machine to form an independent tubular structure. S2. Based on the viscosity of the silicone and the required adhesive layer thickness, select screen printing plates with different mesh counts. The silicone is precisely screen-printed onto the bonding area of ​​the base tube through the screen printing plate to form a uniform adhesive layer. The pre-cut elastic mesh layer is then precisely laid and aligned, and dried and cured. S3. Place the stacked, dried, and cured materials into a hot press for hot pressing and bonding, trim the rough edges, and obtain a shoulder strap containing elastic silicone.

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