High tear resistance colorless transparent fluororubber, its preparation method and use

Abstract

The application provides a high-tear-resistance colorless transparent fluororubber and a preparation method and use thereof, and belongs to the field of chemical materials. The preparation method comprises the following steps: first, plasticizing fluororubber raw rubber, then adding polyurethane acrylate oligomer and mixing uniformly, then adding fluorine-containing resin micro powder and mixing uniformly, and finally adding rubber additives and mixing uniformly to obtain a mixed rubber; and the mixed rubber is subjected to opening, shaping and vulcanization to obtain the fluororubber. The specific process of adding the polyurethane acrylate oligomer first and then adding the fluorine-containing resin micro powder and mixing uniformly, and balancing the functionality, viscosity and addition amount of the polyurethane acrylate oligomer, is used to prepare the fluororubber with high tear resistance and high transparency, and excellent hardness, tensile strength and elongation at break, thereby expanding the application range of the transparent fluororubber in the field of intelligent wear.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials, specifically relating to a high tear-resistant colorless transparent fluororubber, its preparation method, and its uses. Background Technology

[0002] Compared to silicone rubber, fluororubber offers superior durability, weather resistance, and stain resistance. Developing transparent fluororubber materials can better meet the diverse needs of smart wearable devices in terms of appearance, feel, and long-term reliability. However, fluororubber composites are not as easily transparent as polyurethane or silicone rubber. Their practical applications require the addition of various compounding components, such as acid scavengers, reinforcing agents, and vulcanization systems, to meet processing and performance requirements. Currently, the reinforcing agents (such as carbon black, diatomaceous earth, silicates, carbonates, and sulfates), acid scavengers (such as magnesium oxide, calcium oxide, titanium oxide, and zinc oxide), and vulcanizing agents added to fluororubber composites used in wearable devices are all non-transparent components, resulting in a generally non-transparent appearance. Attempts to improve light transmittance by simply simplifying the formula and adding a small amount of silica result in low transparency and insufficient mechanical properties, failing to meet practical application requirements.

[0003] Chinese patent application CN120554865A discloses a colorless and transparent fluororubber smart wearable material, using fluororubber, vulcanizing agent, accelerator, and fluorinated resin micropowder as the main raw materials. Dispersibility is improved by compounding fluorinated resin micropowder of different sizes, thus enhancing the tensile strength and elongation at break of the material while maintaining transparency. However, the fluorinated resin micropowder has low surface energy, strong chemical inertness, and lacks active functional groups, resulting in only a weak physical interface bond with the fluororubber matrix. This makes it difficult to construct a continuous and effective filler network, leading to poor tear resistance and significant limitations in high-end smart wearable applications with complex structures and varying stresses.

[0004] Therefore, how to significantly improve the tear resistance of fluororubber while ensuring its high transparency, and at the same time take into account its comprehensive mechanical properties, has become a technical problem that needs to be solved for transparent fluororubber in the field of smart wearables. Summary of the Invention

[0005] The purpose of this invention is to provide a high tear-resistant, colorless, transparent fluororubber, its preparation method, and its uses.

[0006] The present invention provides a transparent fluororubber, the preparation method of which includes the following steps: (1) first plasticizing the fluororubber raw rubber, then adding polyurethane acrylate oligomer and mixing evenly, then adding fluorinated resin micro powder and mixing evenly, and finally adding rubber additives and mixing evenly to obtain a compound; (2) the compound is obtained after open milling, molding and vulcanization.

[0007] Furthermore, the rubber additives include at least one of vulcanizing agents, accelerators, activators, and processing aids.

[0008] Furthermore, the transparent fluororubber is made from raw materials comprising the following parts by weight: 100 parts of fluororubber raw rubber, 1-8 parts of polyurethane acrylate oligomer, 15-50 parts of fluorinated resin micro powder, 1-5 parts of vulcanizing agent, and 1-5 parts of accelerator.

[0009] Furthermore, the transparent fluororubber is made from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber, 2-5 parts of polyurethane acrylate oligomer, 15-25 parts of fluorinated resin micro powder, 2-4 parts of vulcanizing agent, and 1-2 parts of accelerator.

[0010] Furthermore, the fluororubber raw material is peroxyfluororubber; the polyurethane acrylate oligomer has a functionality of 3-6 and a viscosity of 500-3500 mPa•s at 60°C; the fluorinated resin micro powder is selected from any one of polytetrafluoroethylene micro powder, polychlorotrifluoroethylene micro powder, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and tetrafluoroethylene-ethylene copolymer.

[0011] Furthermore, the polyurethane acrylate oligomer is a fluorinated polyurethane acrylate oligomer.

[0012] Further, the vulcanizing agent is selected from at least one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyn-3, or dicumyl peroxide; the accelerator is selected from at least one of triallyl isocyanurate, trimethylolpropane trimethacrylate, or divinylbenzene.

[0013] This invention also provides a method for preparing transparent fluororubber, comprising the following steps: (1) Plasticize the fluororubber raw rubber, then add polyurethane acrylate oligomer and mix evenly, then add fluorinated resin micro powder and mix evenly, and finally add rubber additives and mix evenly to obtain a compound. (2) The compound rubber is obtained after being processed, molded and vulcanized.

[0014] Further, in step (1), the temperature of plasticizing the fluororubber raw rubber is 50~70℃; in step (2), the molded compound is left to stand for 20~30 hours before vulcanization; the vulcanization temperature is 150~170℃ and the time is 5~15min.

[0015] This invention also provides the use of transparent fluororubber in the manufacture of smart wearable devices.

[0016] This invention produces fluororubber with high tear resistance and high transparency by adding polyurethane acrylate oligomers and then mixing them evenly with fluorinated resin micropowder through a specific process. It also maintains excellent hardness, tensile strength and elongation at break, thus expanding the application scope of transparent fluororubber in the field of smart wearables.

[0017] Specifically, this invention forms a primary crosslinking network through conventional vulcanization (vulcanizing agent) of fluororubber, while a secondary crosslinking network is formed through free radical crosslinking of multifunctional polyurethane acrylate. The two achieve simultaneous crosslinking and interpenetration of molecular chains, forming a fluororubber-polyurethane acrylate interpenetrating polymer network (IPN), which improves the overall network strength and toughness, significantly increases the crosslinking density, and allows stress energy to be evenly distributed in the two networks, avoiding local stress concentration that could lead to cracks. Furthermore, the molecular chains of polyurethane acrylate contain flexible polyurethane segments (soft segments) and rigid acrylate crosslinking segments (hard segments). The soft segments can improve the toughness and resilience of the system, and the tearing energy can be consumed through the stretching and entanglement of the soft segments when cracks propagate. The hard segments can act as physical fulcrums to block crack propagation, thus solving the problem of insufficient toughness in pure fluororubber networks. Meanwhile, polyurethane acrylates are polar polymers with polar groups such as -NH-, -C=O, and -O- in their molecular chains. These groups can form weak dipole interactions with the surfaces of fluororubber and fluororesin micropowders. Simple fluorine modification of polyurethane acrylates (grafting short fluorocarbon chains) can also achieve fluorine-fluorine miscibility, anchoring the polyurethane acrylate molecular chains to the surfaces of fluororubber and fluororesin micropowders, acting as an interfacial bridge and preventing interfacial debonding and crack initiation under stress. The interaction between fluororubber, vulcanizing agents, multifunctional polyurethane acrylates, and fluororesin micropowders forms a strong and tough cross-linked network structure, significantly improving the tear resistance of fluororubber while maintaining its transparency, hardness, tensile strength, and elongation at break.

[0018] Furthermore, the order in which the polyurethane acrylate oligomer and fluorinated resin micropowder are added is crucial. Experiments have shown that changing the order of addition of the trifunctional polyurethane acrylate oligomer and polytetrafluoroethylene micropowder significantly reduces the light transmittance, tear resistance, and other mechanical properties of fluororubber. The functionality of the polyurethane acrylate oligomer also has a significant impact on the tear resistance of fluororubber. Only polyurethane acrylate oligomers with trifunctionality or higher can significantly improve the tear resistance of fluororubber. However, excessively high functionality, exceeding six-functionality, not only leads to excessively high local crosslinking density in the rubber, reducing the uniformity of the crosslinking network and decreasing its tensile strength and elongation at break, but also reduces the light transmittance of fluororubber. At the same time, excessively low viscosity and excessive addition of polyurethane acrylate oligomers also affect the elongation at break of fluororubber, which is detrimental to the overall performance of fluororubber. Excessively viscous polyurethane acrylate oligomers also reduce the light transmittance of fluororubber.

[0019] Therefore, under the specific process of first adding polyurethane acrylate oligomers and mixing them evenly, and then adding fluorinated resin micro powder and mixing them evenly, it is also necessary to balance the functionality, viscosity and addition amount of polyurethane acrylate oligomers to obtain fluororubber with high tear resistance, high transparency and other excellent mechanical properties.

[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. Attached Figure Description

[0022] Figure 1 It is the fluororubber obtained in Example 1 (A) and Comparative Example 3 (B). Detailed Implementation

[0023] The raw materials and equipment used in this invention are all known products, obtained by purchasing commercially available products.

[0024] The fluororubber raw material is peroxyfluororubber, specifically the 246 type fluororubber from Shandong Dongyue Shenzhou New Materials Co., Ltd.; the polytetrafluoroethylene micro powder, with a particle size of 20-30μm, is DF-162 from Shandong Dongyue Polymer Materials Co., Ltd.; the bifunctional polyurethane acrylate oligomers, trifunctional polyurethane acrylate oligomers, and hexafunctional polyurethane acrylate oligomers were purchased from Guangzhou Runao Chemical Materials Co., Ltd.

[0025] Example 1: Preparation of Fluororubber Formula (parts by weight): 100 parts of fluororubber raw rubber, 2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1.5 parts of triallyl isocyanurate, 20 parts of polytetrafluoroethylene micro powder, and 2 parts of trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity at 60℃ is 2200 mPa•s); Prepare according to the formula as follows: (1) Put the fluororubber raw rubber into a mixer and heat it to 60°C. First, add the trifunctional polyurethane acrylate oligomer LuCure®8006 and mix it evenly. Then add the polytetrafluoroethylene micro powder and mix it evenly. Then add 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and triallyl isocyanurate. After mixing evenly, take it out to obtain the compound rubber. (2) The mixed rubber is fed into the open mill to produce sheets, then mixed evenly in two rollers, and after being rolled into triangular shapes three times, it is sheeted out. After being left to stand for 24 hours, it is vulcanized at 160°C for 10 minutes in a flat vulcanizing machine to obtain fluororubber.

[0026] Example 2: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity of 2200 mPa•s at 60°C) in the formulation is 5 parts.

[0027] Example 3: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity of 2200 mPa•s at 60°C) in the formulation is replaced with the hexafunctional polyurethane acrylate oligomer Uniclil® R7109 (viscosity of 1720 mPa•s at 60°C).

[0028] Example 4: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity of 2200 mPa•s at 60°C) in the formulation is replaced with the trifunctional polyurethane acrylate oligomer LuCure® 8300 (viscosity of 500 mPa•s at 60°C).

[0029] Example 5: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity of 2200 mPa•s at 60°C) in the formulation is replaced with the trifunctional polyurethane acrylate oligomer LuCure® 8944 (viscosity of 3000 mPa•s at 60°C).

[0030] Comparative Example 1: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 is not added.

[0031] Comparative Example 2: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity of 2200 mPa•s at 60°C) in the formulation is replaced with the difunctional polyurethane acrylate oligomer LuCure® 5956 (viscosity of 2300 mPa•s at 60°C).

[0032] Comparative Example 3: Preparation of Fluororubber Referring to Example 1, the only difference is that the preparation step (1) is as follows: put the fluororubber raw rubber into a mixer and heat it to 60°C. First, add polytetrafluoroethylene micro powder and mix it evenly. Then, add trifunctional polyurethane acrylate oligomer LuCure®8006 and mix it evenly. Then, add 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and triallyl isocyanurate. After mixing evenly, take it out to obtain the compound rubber.

[0033] Comparative Example 4: Preparation of Fluororubber Referring to Example 1, the only difference is that the trifunctional polyurethane acrylate oligomer LuCure® 8006 (viscosity of 2200 mPa•s at 60°C) in the formulation is replaced with the decafunctional polyurethane acrylate oligomer LuCure® 2159 (viscosity of 1500 mPa•s at 60°C).

[0034] Experimental Examples and Performance Testing of Fluororubber 1. Experimental Methods Hardness testing was conducted according to national standard GB / T531.1-2008, using a Shore A hardness tester. Tensile strength and elongation at break were measured according to national standard GB / T 528-2009. Tear strength testing was conducted according to GB / T 529-2008, testing the tear strength of a right-angled specimen. The strap tensile strength was measured using a tensile tester. A vertical force was applied to the strap using upper and lower clamps, continuously stretching it until the perforation cracked or the strap broke, obtaining the maximum tensile strength value. The testing speed was 30 mm / min. Light transmittance was measured using a UV-Vis spectrophotometer, measuring the average transmittance of samples within the wavelength range of 400~1100 nm.

[0035] 2. Experimental Results As shown in Table 1, compared with Comparative Example 1, the fluororubbers obtained in Examples 1-5 all showed significantly improved tear strength and tensile strength, while maintaining high hardness, tensile strength, elongation at break and light transmittance. This proves that the present invention can effectively improve the tear resistance of fluororubber without affecting light transmittance and other mechanical properties.

[0036] Compared with Examples 1-5, Comparative Example 3 changed the order of addition of polytetrafluoroethylene micropowder and trifunctional polyurethane acrylate oligomer. The fluororubber prepared in Comparative Example 3 not only significantly reduced tear strength and tensile strength, but also significantly reduced light transmittance. Figure 1Other mechanical properties also decreased, indicating that the order of adding polytetrafluoroethylene micro powder and trifunctional polyurethane acrylate oligomer has a key impact on the mechanical properties and light transmittance of fluororubber, especially light transmittance. This shows that only by first adding trifunctional polyurethane acrylate oligomer and mixing it evenly, and then adding polytetrafluoroethylene micro powder and mixing it evenly, can fluororubber with high tear resistance and high transparency be obtained, while maintaining excellent hardness, tensile strength and elongation at break.

[0037] Comparative Example 2, using a difunctional polyurethane acrylate oligomer, produced fluororubber with tear strength and tensile strength comparable to Comparative Example 1. However, compared to Example 1, which used a trifunctional polyurethane acrylate oligomer, the fluororubber exhibited significantly reduced tear strength and tensile strength. This indicates that only trifunctional or higher-functionality polyurethane acrylate oligomers can significantly improve the tear resistance of fluororubber. In contrast, Comparative Example 4, using a decafunctional polyurethane acrylate oligomer, produced fluororubber that not only reduced light transmittance, tear strength, and tensile strength but also significantly reduced elongation at break. This suggests that excessively high functionality polyurethane acrylate oligomers can negatively impact the light transmittance and mechanical properties of fluororubber. These results demonstrate that only polyurethane acrylate oligomers with appropriate functionality can yield fluororubber that combines high tear resistance and high transparency with excellent other mechanical properties.

[0038] Furthermore, compared with Example 1, although the tear strength and tensile strength of the fluororubber prepared in Examples 2-4 were improved, its elongation at break was reduced, indicating that increasing the amount of polyurethane acrylate oligomer, low viscosity, and increased functionality all affect the overall performance of fluororubber. Compared with Example 1, the viscosity of the trifunctional polyurethane acrylate oligomer in Example 5 increased from 2200 mPa•s to 3000 mPa•s at 60°C, and its light transmittance decreased, indicating that increasing viscosity (molecular weight) affects the light transmittance of fluororubber.

[0039] Table 1. Performance test data of fluororubber In summary, this invention produces fluororubber with high tear resistance and high transparency by adding polyurethane acrylate oligomers and then mixing them evenly with fluorinated resin micropowder through a specific process, while maintaining excellent hardness, tensile strength and elongation at break. Experiments have shown that changing the order of addition of trifunctional polyurethane acrylate oligomers and polytetrafluoroethylene (PTFE) micropowder significantly reduces the light transmittance, tear resistance, and other mechanical properties of fluororubber. Meanwhile, difunctional polyurethane acrylate oligomers do not effectively improve the tear resistance of fluororubber, hexafunctional polyurethane acrylate oligomers reduce the elongation at break of fluororubber, and decafunctional polyurethane acrylate oligomers not only reduce the elongation at break and tear resistance of fluororubber but also significantly reduce its light transmittance. Furthermore, excessive addition or excessively low viscosity of polyurethane acrylate oligomers also reduces the elongation at break of fluororubber, while excessive viscosity affects its light transmittance. This indicates that under specific processes, it is necessary to balance the functionality, addition amount, and viscosity of the polyurethane acrylate oligomers to significantly improve the tear resistance of fluororubber while ensuring its excellent light transmittance and other mechanical properties.

Claims

1. A transparent fluororubber, characterized in that, Its preparation method includes the following steps: (1) First, plasticize the fluororubber raw rubber, then add polyurethane acrylate oligomer and mix evenly, then add fluorinated resin micro powder and mix evenly, and finally add rubber additives and mix evenly to obtain the compound; (2) The compound is obtained after open milling, molding and vulcanization.

2. The transparent fluororubber according to claim 1, characterized in that, The rubber additives include at least one of vulcanizing agents, accelerators, activators, and processing aids.

3. The transparent fluororubber according to claim 2, characterized in that, It is made from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber, 1-8 parts of polyurethane acrylate oligomer, 15-50 parts of fluorinated resin micro powder, 1-5 parts of vulcanizing agent, and 1-5 parts of accelerator.

4. The transparent fluororubber according to claim 3, characterized in that, It is made from the following raw materials in parts by weight: 100 parts of fluororubber raw rubber, 2-5 parts of polyurethane acrylate oligomer, 15-25 parts of fluorinated resin micro powder, 2-4 parts of vulcanizing agent, and 1-2 parts of accelerator.

5. The transparent fluororubber according to any one of claims 1 to 4, characterized in that, The fluororubber raw material is peroxyfluororubber; the polyurethane acrylate oligomer has a functionality of 3-6 and a viscosity of 500-3500 mPa•s at 60°C; the fluorinated resin micro powder is selected from any one of polytetrafluoroethylene micro powder, polychlorotrifluoroethylene micro powder, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and tetrafluoroethylene-ethylene copolymer.

6. The transparent fluororubber according to claim 5, characterized in that, The polyurethane acrylate oligomer is a fluorinated polyurethane acrylate oligomer.

7. The transparent fluororubber according to any one of claims 2 to 4, characterized in that, The vulcanizing agent is selected from at least one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyn-3, or dicumyl peroxide; the accelerator is selected from at least one of triallyl isocyanurate, trimethylolpropane trimethacrylate, or divinylbenzene.

8. A method for preparing the transparent fluororubber according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Plasticize the fluororubber raw rubber, then add polyurethane acrylate oligomer and mix evenly, then add fluorinated resin micro powder and mix evenly, and finally add rubber additives and mix evenly to obtain a compound. (2) The compound rubber is obtained after being processed, molded and vulcanized.

9. The preparation method according to claim 8, characterized in that, In step (1), the temperature of plasticizing the fluororubber raw rubber is 50~70℃; in step (2), the molded compound is left to stand for 20~30 hours before vulcanization; the vulcanization temperature is 150~170℃ and the time is 5~15min.

10. Use of the transparent fluororubber according to any one of claims 1 to 7 in the preparation of smart wearable devices.

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