Low-toxicity and low-sensitization fluororubber watchband adhesive as well as preparation method and application thereof

Abstract

The invention provides low-toxicity and low-sensitization fluororubber watchband glue as well as a preparation method and application thereof, and belongs to the technical field of rubber materials. According to the technical scheme of the invention, the raw fluororubber is polymerized by adopting the surfactant containing no fluorine element, and meanwhile, the reinforcing filler system is optimized, so that the skin sensitization and stimulation risks are remarkably reduced. The fluororubber watchband adhesive prepared by the preparation method disclosed by the invention shows excellent biological safety in a cytotoxicity test. The invention provides a novel environment-friendly material solution with safety and reliability for the field of wearable equipment, particularly watchband products in long-term contact with human skin, and has definite market application prospect and popularization value.

Description

Technical Field

[0001] This invention belongs to the field of rubber materials technology, specifically relating to a low-toxicity, low-allergenic fluororubber watch strap adhesive, its preparation method, and its application. Background Technology

[0002] In the field of smart wearables, fluororubber is often chosen as a watch strap material due to its excellent resistance to chemical media, especially its resistance to skin oils and sweat. Traditional fluororubber watch strap adhesives mainly consist of two components: fluororubber raw rubber and reinforcing fillers. While the synthesis and processing systems of fluororubber are relatively mature in current technologies, its biocompatibility and long-term health risks remain unresolved for high-standard applications involving long-term direct contact with human skin.

[0003] The environmental residues and potential health effects of fluorinated compounds (such as surfactants containing polyfluoroalkyl substances (PFAS)) are receiving increasing attention, with the risk of migration and skin irritation under prolonged contact with bodily fluids such as sweat. These factors collectively limit the wider application of fluororubber in fields with stringent requirements for material biocompatibility, such as high-end consumer electronics and medical wearables.

[0004] While the industry has explored various methods to improve the durability and chemical stability of rubber materials, a comprehensive material solution that is both innovative and practical remains lacking: how to systematically and fundamentally reduce the long-term potential irritation and sensitization risks of fluororubber wearable products to human skin while maintaining their necessary physicochemical properties. Therefore, developing a fluororubber material designed from the outset to achieve higher biocompatibility and better suitability for long-term skin contact has become an urgent technical challenge to overcome in this field. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of this invention is to provide a low-toxicity, low-allergenic fluororubber watch strap adhesive, its preparation method and application, so as to improve the allergenicity and resilience of fluororubber.

[0006] To achieve the above objectives, the specific technical solution of the present invention is as follows: This invention provides a fluororubber watch strap adhesive, which is prepared from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber; 1-50 parts of non-metallic reinforcing filler; 1-10 parts of crosslinking agent; 1-5 parts of vulcanizing agent; 1-5 parts of processing aid; The fluororubber raw rubber is obtained by high-pressure emulsion polymerization of fluorinated monomers in an aqueous medium under the action of a surfactant and initiator that does not contain fluorine.

[0007] Further, the fluorinated monomer is hexafluoropropylene (HFP) and vinylidene fluoride (VDF); the surfactant is alkylphenol polyoxyethylene ether; the initiator is potassium persulfate; the molar ratio of hexafluoropropylene to vinylidene fluoride is 1:1~3; the mass ratio of the fluorinated monomer, surfactant and initiator is 100:1~5:0.5~3; the reaction pressure is 5~10 MPa and the temperature is 50~80℃.

[0008] Furthermore, the molar ratio of hexafluoropropylene to vinylidene fluoride is 1:2; the mass ratio of the fluorinated monomer, surfactant, and initiator is 100:3:1; and the reaction pressure is 7 MPa and the temperature is 70°C.

[0009] Furthermore, the fluororubber watch strap adhesive is prepared from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber; 5-15 parts of non-metallic reinforcing filler; 1-5 parts of crosslinking agent; 1-3 parts of vulcanizing agent; and 1-3 parts of processing aid.

[0010] Furthermore, the fluororubber watch strap adhesive is prepared from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber; 10 parts of non-metallic reinforcing filler; 2.5 parts of crosslinking agent; 1 part of vulcanizing agent; and 1 part of processing aid.

[0011] Furthermore, the non-metallic reinforcing filler is nano-silica; The crosslinking agent is selected from triallyl isocyanurate or trimethylolpropane trimethacrylate; The vulcanizing agent is selected from bis-(tert-butylperoxyisopropyl)benzene or 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The processing aid is a hydrophilic polymer.

[0012] Furthermore, the non-metallic reinforcing filler is fumed nano silica; the crosslinking agent is triallyl isocyanurate; the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and the processing aid is polyethylene glycol.

[0013] The present invention also provides a method for preparing the above-mentioned fluororubber watch strap adhesive, the method comprising the following steps: mixing raw materials to obtain a compound; vulcanizing and molding the compound to obtain the fluororubber watch strap adhesive.

[0014] Furthermore, the mixing temperature is 40~80℃ and the time is 5~20min.

[0015] Furthermore, the mixing temperature is 60°C and the time is 10 minutes.

[0016] Furthermore, the vulcanization is divided into a first-stage vulcanization and a second-stage vulcanization. The pressure of the first-stage vulcanization is 10~30MPa, the temperature is 150~200℃, and the time is 5~30min. The temperature of the second-stage vulcanization is 150~200℃, and the time is 2~8h.

[0017] Furthermore, the pressure of the first stage of vulcanization is 20 MPa, the temperature is 180°C, and the time is 10 min; the temperature of the second stage of vulcanization is 180°C, and the time is 6 h.

[0018] The present invention also provides the use of the above-mentioned fluororubber strap adhesive in the preparation of wearable watch strap materials.

[0019] The present invention has achieved the following beneficial effects: The technical solution of this invention significantly reduces the risk of skin sensitization and irritation by using a fluorine-free surfactant-based polyfluororubber raw material and optimizing the reinforcing filler system. The fluororubber watch strap adhesive prepared by this invention exhibits excellent biocompatibility in cytotoxicity tests. This invention provides a novel environmentally friendly material solution that combines safety and reliability for wearable devices, especially watch strap products that come into prolonged contact with human skin, and has clear market application prospects and promotional value.

[0020] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0021] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Detailed Implementation

[0022] The raw materials and equipment used in this invention are all known products, obtained by purchasing commercially available products.

[0023] In the formulation of the specific embodiments of the present invention, "part" refers to parts by weight, and 1 part is 1g.

[0024] Example 1: Preparation of low-toxicity, low-allergenic fluororubber watch strap adhesive (1) Preparation of raw polyfluororubber without fluorinated surfactant Using an aqueous phase as a medium, 100 parts of fluorinated monomers (hexafluoropropylene (HFP) and vinylidene fluoride (VDF) in a molar ratio of 1:2) were subjected to high-pressure emulsion polymerization (reaction temperature 70℃, reaction pressure 7MPa) with 3 parts of surfactant (alkylphenol polyoxyethylene ether) and 1 part of initiator (potassium persulfate) to obtain non-fluorinated surfactant-containing polyfluororubber raw rubber.

[0025] (2) Preparation of compound rubber 100 parts of non-fluorinated surfactant polyfluororubber raw rubber, 10 parts of nano silica (specific surface area 100±20 m² / g), 2.5 parts of liquid triallyl isocyanurate (TAIC), 1 part of liquid 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis(diphenylpentane)) and 1 part of polyethylene glycol (PEG-2000) were put into an internal mixer and mixed at 60°C for 10 min. After the mixture was uniformly mixed, it was taken out and placed on a two-roll mill for thin-passing (with a roller spacing of 1 mm and a roller speed of 50 r / min) to obtain a low-toxicity, low-allergenic fluororubber compound.

[0026] (3) Sulfidation Low-toxicity, low-allergenic fluororubber watch strap rubber can be obtained by subjecting the fluororubber compound to one-stage and two-stage vulcanization (one-stage vulcanization: press at 20MPa and 180℃ for 10min; two-stage vulcanization: continue at 180℃ for 6h).

[0027] The following is a comparative example.

[0028] Comparative Example 1: Preparation of Fluororubber Watch Strap Adhesive The preparation method of Example 1 is the same, except that the non-fluorinated surfactant polyfluororubber raw rubber is replaced with traditional fluororubber raw rubber (Zhejiang Juhua binary fluororubber) to prepare fluororubber watch strap adhesive.

[0029] Comparative Example 2: Preparation of Fluororubber Watch Strap Adhesive The preparation method of Example 1 is referenced, except that fumed nano-silica is replaced with diatomaceous earth to prepare fluororubber watch strap adhesive.

[0030] Comparative Example 3: Preparation of Fluororubber Watch Strap Adhesive The preparation method of Example 1 is referenced, except that fumed nano-silica is replaced with calcium silicate to prepare fluororubber watch strap adhesive.

[0031] Comparative Example 4: Preparation of Fluororubber Watch Strap Adhesive The preparation method of Example 1 is the same, except that the non-fluorinated surfactant polyfluororubber raw rubber is replaced with traditional fluororubber raw rubber (Zhejiang Juhua binary fluororubber), and the fumed nano silica is replaced with diatomaceous earth to prepare fluororubber watch strap adhesive.

[0032] The mechanical properties (including tensile strength and elongation at break) of the fluororubber watch strap adhesive of Example 1 of the present invention meet the requirements for use. The following experimental examples focus on evaluating the cytotoxicity of the fluororubber watch strap adhesive.

[0033] Experimental Example 1: Cytotoxicity Test of Fluororubber Watch Strap Adhesive 1. Experimental Methods The samples were extracted according to the requirements of GB / T16886.12-2017, and the extracts were subjected to in vitro cytotoxicity tests according to the methods recommended in Appendix C of GB / T16886.5-2017 "Biological evaluation of medical devices - Part 5: In vitro cytotoxicity tests".

[0034] 2. Experimental Results This invention evaluated the cytotoxicity of different fluororubber watch strap adhesives, and the results are shown in Table 1.

[0035] Table 1. Cell viability test results of different fluororubber watch strap adhesives Cell viability is a key indicator for assessing the biocompatibility of materials; a higher activity value indicates lower cytotoxicity. As shown in Table 1, the fluororubber watch strap adhesive prepared in Example 1 of this invention exhibits a cell viability as high as 85%, significantly higher than all comparative examples (57%~70%). This result indicates that the fluororubber watch strap adhesive of Example 1 has the least cytotoxic effect, demonstrating the best biocompatibility. In summary, the technical solution of this invention has achieved significant results in effectively reducing the biotoxicity of fluororubber watch straps.

[0036] In summary, this invention provides a low-toxicity, low-allergenic fluororubber watch strap adhesive, its preparation method, and its applications. The technical solution of this invention significantly reduces the risk of skin sensitization and irritation by using a fluorine-free surfactant-based polymerized fluororubber raw material and optimizing the reinforcing filler system. The fluororubber watch strap adhesive prepared by this invention exhibits excellent biocompatibility in cytotoxicity tests. This invention provides a novel environmentally friendly material solution that combines safety and reliability for wearable devices, especially watch strap products that come into prolonged contact with human skin, and has clear market application prospects and promotional value.

Claims

1. A fluororubber watch strap adhesive, characterized in that: The fluororubber watch strap adhesive is prepared from the following raw materials in parts by weight: 100 parts fluororubber raw rubber; 1-50 parts non-metallic reinforcing filler; 1-10 parts crosslinking agent; 1-5 parts vulcanizing agent; and 1-5 parts processing aid. The fluororubber raw rubber is obtained by high-pressure emulsion polymerization of fluorinated monomers in an aqueous medium under the action of a surfactant and initiator that does not contain fluorine.

2. The fluororubber watch strap adhesive according to claim 1, characterized in that: The fluorinated monomers are hexafluoropropylene and vinylidene fluoride; the surfactant is alkylphenol polyoxyethylene ether; the initiator is potassium persulfate; the molar ratio of hexafluoropropylene to vinylidene fluoride is 1:1~3; the mass ratio of the fluorinated monomer, surfactant and initiator is 100:1~5:0.5~3; the reaction pressure is 5~10MPa and the temperature is 50~80℃.

3. The fluororubber watch strap adhesive according to claim 1, characterized in that: The fluororubber watch strap adhesive is prepared from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber; 5-15 parts of non-metallic reinforcing filler; 1-5 parts of crosslinking agent; 1-3 parts of vulcanizing agent; and 1-3 parts of processing aid.

4. The fluororubber watch strap adhesive according to claim 3, characterized in that: The fluororubber watch strap adhesive is prepared from the following raw materials in parts by weight: 100 parts fluororubber raw rubber; 10 parts non-metallic reinforcing filler; 2.5 parts crosslinking agent; 1 part vulcanizing agent; and 1 part processing aid.

5. The fluororubber watch strap adhesive according to any one of claims 1 to 4, characterized in that: The non-metallic reinforcing filler is nano-silica; The crosslinking agent is selected from triallyl isocyanurate or trimethylolpropane trimethacrylate; The vulcanizing agent is selected from bis-(tert-butylperoxyisopropyl)benzene or 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The processing aid is a hydrophilic polymer.

6. The fluororubber watch strap adhesive according to claim 5, characterized in that: The non-metallic reinforcing filler is fumed nano silica; the crosslinking agent is triallyl isocyanurate; the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; and the processing aid is polyethylene glycol.

7. A method for preparing the fluororubber watch strap adhesive according to any one of claims 1 to 6, characterized in that: The method includes the following steps: mixing raw materials to obtain a compound; vulcanizing and molding the compound to obtain the fluororubber watch strap adhesive.

8. The method according to claim 7, characterized in that: The mixing temperature is 40~80℃ and the time is 5~20min.

9. The method according to claim 7, characterized in that: The vulcanization process is divided into a first-stage vulcanization and a second-stage vulcanization. The first-stage vulcanization is carried out at a pressure of 10-30 MPa, a temperature of 150-200°C, and a time of 5-30 min. The second-stage vulcanization is carried out at a temperature of 150-200°C and a time of 2-8 h.

10. Use of the fluororubber strap adhesive according to any one of claims 1 to 6 in the preparation of wearable watch strap materials.

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