A high-density silicone rubber watch strap and its preparation method and use

Abstract

The present invention belongs to the technical field of silicone rubber preparation, and specifically relates to a high-density silicone rubber strap and its preparation method and use. The present invention prepares a silicone rubber strap with high density and good mechanical properties by screening the ball milling time and the amount of barium sulfate, adding solid silicone rubber for mixing. By regulating the content of barium sulfate and the ball milling time, the density of the silicone rubber can reach 1.3-1.9 g / cm 3 The density is equivalent to that of fluororubber; the tensile strength is greater than 4MPa. The silicone rubber prepared by the present invention achieves both high density and good mechanical properties, has good texture, and can also be used to prepare silicone rubber straps of different densities according to needs, and has good application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber preparation, and in particular relates to a high-density silicone rubber watch strap and a preparation method and application thereof. Background Art

[0002] In today's smart wearable market, the choice of watch strap is not only about personal taste, but also the key to a comfortable experience. Silicone watch straps have become the first choice of many users with their unique materials and diverse designs. The main material of silicone watch straps is silicone rubber, which is a polymer compound with high tensile strength and tear resistance, good softness and elasticity, and can quickly recover to its original shape. Silicone material also has good resistance to many chemicals, acid, alkali and solvent resistance. In addition, silicone material has good high temperature resistance and can change in the temperature range between -55℃ and 300℃ without damage, which allows silicone watch straps to maintain performance even in extreme environments. Compared with other materials: (1) Silicone watch straps are skin-friendly and basically feel-free when worn, suitable for long-term wear; (2) Silicone material is completely waterproof and is mostly used in diving and sports watches. It has excellent properties in sweat and moisture resistance; (3) Silicone watch straps have excellent wear resistance and waterproof properties, and are strong and durable; (4) Silicone is an environmentally friendly material that can be recycled and is environmentally friendly.

[0003] However, compared with fluororubber straps, silicone straps have a relatively poor appearance and texture, lacking a sense of luxury and refinement. This is mainly because the density of silicone rubber is too low, usually between 0.8-1.3g / cm 3 In order to increase the density of silicone rubber, people have taken a variety of improvement measures, including adding fillers, optimizing the types and ratios of silicone rubber monomers, etc. However, these improvements may lead to reduced mechanical properties of silicone rubber, making it difficult to balance the high density and good mechanical properties of silicone rubber.

[0004] In order to improve the mechanical properties of silicone rubber, researchers have made a variety of improvements, such as optimizing the type, amount and pretreatment method of fillers, etc. These methods effectively improve the mechanical properties of silicone rubber such as tensile strength, but cannot meet the needs of high density.

[0005] Therefore, how to optimize the type, amount and processing method of filler to prepare a silicone rubber with both high density and good mechanical properties is a problem faced by this field. Summary of the invention

[0006] In view of the defects of the prior art, the present invention provides a preparation process of adding fillers, aiming at preparing a silicone rubber and a strap thereof with high density and good mechanical properties.

[0007] The present invention provides a high-density silicone rubber filler, which comprises the following raw materials in parts by weight:

[0008] 40-140 parts of barium sulfate, 30-50 parts of silicon dioxide, 5-10 parts of silane coupling agent;

[0009] The raw materials are ball-milled for 5-60 minutes.

[0010] Preferably, the ball milling time is 5-35 minutes.

[0011] Preferably, the ball milling time is 35 minutes.

[0012] Preferably, the amount of barium sulfate is 140 parts.

[0013] Preferably, the silicon dioxide is fumed silicon dioxide; the silane coupling agent is selected from vinyl triethoxysilane, vinyl tri (2-methoxyethoxy) silane, vinyl triisopropoxy silane, 3- (methacryloyloxy) propyl trimethoxy silane; the raw materials also include 10-30 parts by weight of titanium dioxide.

[0014] The present invention provides a method for preparing the high-density silicone rubber filler described in any one of the above items, comprising the following steps:

[0015] The barium sulfate is ball-milled with silicon dioxide and a silane coupling agent to obtain the product.

[0016] The present invention provides a high-density silicone rubber, which comprises the following raw materials in parts by weight:

[0017] 90-210 parts of the high-density silicone rubber filler described in any one of the above items,

[0018] Silicone rubber 80-120 parts,

[0019] 1-3 parts of vulcanizing agent.

[0020] Preferably, the silicone rubber is selected from methyl vinyl silicone rubber and methyl silicone rubber, and the vulcanizing agent is selected from dipentadienyl peroxide, dicumyl peroxide and 2,4-di-tert-butylcumyl peroxide.

[0021] The present invention provides a method for preparing the high-density silicone rubber described in any one of the above items, which comprises: kneading the high-density silicone rubber filler with silicone rubber and a vulcanizing agent to obtain the high-density silicone rubber.

[0022] The present invention provides use of any of the above-mentioned high-density silicone rubbers in the preparation of sealing materials, shock-absorbing materials, medical devices, and wearable devices.

[0023] The term "mixing" is a term used in the preparation of silicone rubber, which refers to the mixing and plasticizing of silicone rubber raw rubber with various compounding agents (such as vulcanizers, fillers, plasticizers, antioxidants, etc.) in specific equipment. Specific equipment includes kneaders, open mills and internal mixers.

[0024] The present invention prepares hydrophobic barium sulfate as a modified filler by screening the ball milling time and the amount of barium sulfate, and then adds solid silicone rubber to mix and prepare a silicone rubber strap with high density and good mechanical properties. By adjusting the content of barium sulfate and the ball milling time, the density of the silicone rubber can reach 1.3-1.9g / cm 3 The density is equivalent to that of fluororubber; the tensile strength is greater than 4MPa. The silicone rubber prepared by the present invention achieves both high density and good mechanical properties, has good texture, and can also be used to prepare silicone rubber straps of different densities and properties as needed, with good application prospects.

[0025] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0026] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. DETAILED DESCRIPTION

[0027] In the following examples and experimental examples, reagents and materials not particularly described are all commercially available.

[0028] The methyl vinyl silicone rubber used in the present invention is 110-2 methyl vinyl silicone rubber purchased from Hesheng Silicon Industry; the fumed silica is Evonik R812.

[0029] Example 1 A barium sulfate modified silicone rubber and its strap

[0030] The barium sulfate-modified silicone rubber and its strap of this embodiment are prepared by the following method:

[0031] (1) Preparation of hydrophobic barium sulfate

[0032] 40 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane (CAS No. 78-08-0) and 10 g of titanium dioxide were placed in a ball mill and ball-milled for 20 min to prepare hydrophobic barium sulfate A;

[0033] (2) Preparation of silicone rubber strap compound

[0034] The hydrophobic barium sulfate A, 100 g of methyl vinyl silicone rubber and 1 g of a vulcanizing agent, were placed in a kneader and mixed at 30° C. for 2 h.

[0035] (3) Preparation of silicone rubber strap

[0036] A silicone rubber watch strap mixed rubber specimen was prepared on an open mixing mill, the specimen was placed in a watch strap mold, and the silicone rubber watch strap was prepared by hot pressing at a pressure of 15 MPa.

[0037] Example 2 A barium sulfate modified silicone rubber and its strap

[0038] The barium sulfate-modified silicone rubber and its strap of this embodiment are prepared by the following method:

[0039] (1) Preparation of hydrophobic barium sulfate

[0040] 75 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane (CAS No. 78-08-0) and 15 g of titanium dioxide were placed in a ball mill and milled for 25 min to obtain hydrophobic barium sulfate B;

[0041] (2) Preparation of silicone rubber strap compound

[0042] The hydrophobic barium sulfate B, 100g methyl vinyl silicone rubber and 1g vulcanizing agent di-2-5 were placed in a kneader and mixed at 30°C for 2h;

[0043] (3) Preparation of silicone rubber strap

[0044] A silicone rubber watch strap mixed rubber specimen was prepared on an open mixing mill, the specimen was placed in a watch strap mold, and the silicone rubber watch strap was prepared by hot pressing at a pressure of 15 MPa.

[0045] Example 3: A barium sulfate-modified silicone rubber and its strap

[0046] The barium sulfate-modified silicone rubber and its strap of this embodiment are prepared by the following method:

[0047] (1) Preparation of hydrophobic barium sulfate

[0048] 110 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane (CAS No. 78-08-0) and 20 g of titanium dioxide were placed in a ball mill and ball-milled for 30 min to obtain hydrophobic barium sulfate C;

[0049] (2) Preparation of silicone rubber strap compound

[0050] The hydrophobic barium sulfate C, 100 g of methyl vinyl silicone rubber, and 1 g of a vulcanizing agent, bis(2-5-nitrogen) were placed in a kneader and mixed at 30°C for 2 h.

[0051] (3) Preparation of silicone rubber strap

[0052] A silicone rubber watch strap mixed rubber specimen was prepared on an open mixing mill, the specimen was placed in a watch strap mold, and the silicone rubber watch strap was prepared by hot pressing at a pressure of 15 MPa.

[0053] Example 4: A barium sulfate-modified silicone rubber and its strap

[0054] The barium sulfate-modified silicone rubber and its strap of this embodiment are prepared by the following method:

[0055] (1) Preparation of hydrophobic barium sulfate

[0056] 140 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane (CAS No. 78-08-0) and 30 g of titanium dioxide were placed in a ball mill and ball-milled for 35 min to obtain hydrophobic barium sulfate D;

[0057] (2) Preparation of silicone rubber strap compound

[0058] The hydrophobic barium sulfate D, 100 g of methyl vinyl silicone rubber, and 1 g of a vulcanizing agent, bis(2-5-nitrogen) were placed in a kneader and mixed at 30°C for 2 h.

[0059] (3) Preparation of silicone rubber strap

[0060] A silicone rubber watch strap mixed rubber specimen was prepared on an open mixing mill, the specimen was placed in a watch strap mold, and the silicone rubber watch strap was prepared by hot pressing at a pressure of 15 MPa.

[0061] Example 5: A barium sulfate-modified silicone rubber and its strap

[0062] The barium sulfate-modified silicone rubber and its strap of this embodiment are prepared by the following method:

[0063] (1) Preparation of hydrophobic barium sulfate

[0064] 140 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane (CAS No. 78-08-0) and 30 g of titanium dioxide were placed in a ball mill and ball-milled for 5 minutes to prepare hydrophobic barium sulfate E;

[0065] (2) Preparation of silicone rubber strap compound

[0066] The hydrophobic barium sulfate E, 100 g of methyl vinyl silicone rubber, and 1 g of a vulcanizing agent, bis(2-5-nitrogen) were placed in a kneader and mixed at 30°C for 2 h.

[0067] (3) Preparation of silicone rubber strap

[0068] A silicone rubber watch strap mixed rubber specimen was prepared on an open mixing mill, the specimen was placed in a watch strap mold, and the silicone rubber watch strap was prepared by hot pressing at a pressure of 15 MPa.

[0069] Example 6: A barium sulfate-modified silicone rubber and its strap

[0070] The barium sulfate-modified silicone rubber and its strap of this embodiment are prepared by the following method:

[0071] (1) Preparation of hydrophobic barium sulfate

[0072] 140 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane (CAS No. 78-08-0) and 30 g of titanium dioxide were placed in a ball mill and ball-milled for 60 min to obtain hydrophobic barium sulfate F;

[0073] (2) Preparation of silicone rubber strap compound

[0074] The hydrophobic barium sulfate F, 100g methyl vinyl silicone rubber and 1g vulcanizing agent di-2-5 were placed in a kneader and mixed at 30°C for 2h;

[0075] (3) Preparation of silicone rubber strap

[0076] A silicone rubber watch strap mixed rubber specimen was prepared on an open mixing mill, the specimen was placed in a watch strap mold, and the silicone rubber watch strap was prepared by hot pressing at a pressure of 15 MPa.

[0077] Comparative Example 1

[0078] 140 g of barium sulfate, 100 g of methyl vinyl silicone rubber and 1 g of vulcanizing agent dichloromethane were mixed together in a kneader at 30° C. for 2 h, and then a silicone rubber watch strap was prepared according to the method of Example 1.

[0079] Comparative Example 2

[0080] 140 g of barium sulfate, 30 g of fumed silica, 10 g of vinyl triethoxysilane, 30 g of titanium dioxide, 100 g of methyl vinyl silicone rubber and 1 g of vulcanizing agent dichloromethane were mixed together in a kneader at 30° C. for 2 h, and then a silicone rubber watch strap was prepared according to the method of Example 1.

[0081] Comparative Example 3

[0082] 100 g of methyl vinyl silicone rubber and 1 g of vulcanizing agent dichloromethane were mixed together in a kneader at 30° C. for 2 h, and then a silicone rubber watch strap was prepared according to the method of Example 1.

[0083] The technical solution of the present invention is further described below through experiments. The samples tested in the following experimental examples are prepared by the methods of Examples 1-5 and Comparative Examples 1, 2, and 3.

[0084] Experimental Example 1 Density and Mechanical Properties of Modified Silicone Rubber

[0085] 1. Experimental Methods

[0086] Hydrophobic barium sulfate and silicone rubber watchband rubber mixes were prepared according to the methods of Examples 1-5 and Comparative Examples 1 and 2. Silicone rubber watchband rubber mix samples and strips were prepared on an open mill, and the samples were placed in a flat vulcanizer to prepare test pieces, and their tensile strength, elongation at break and density were tested. The strips were placed in a watchband mold, and silicone rubber watchbands were prepared by hot pressing at a pressure of 15 MPa, and the watchband tension was tested.

[0087] 2. Experimental Results

[0088] The comparative results are shown in Table 1. Comparative Example 3 does not add filler, but only mixes silane raw rubber and vulcanizing agent, and its density is very low and its mechanical properties are very poor. Compared with Comparative Example 3, the introduction of barium sulfate greatly increases the density of silica gel, but its mechanical properties are still poor.

[0089] It can be seen from the data of Comparative Examples 1 and 2 that the introduction of fumed silica, vinyl triethoxy silane and titanium dioxide does not significantly change the density of silicone rubber, but has a certain improvement on the mechanical properties of silicone rubber, indicating that the introduction of fumed silica, vinyl triethoxy silane and titanium dioxide has no obvious effect on the density of silicone rubber, but has a certain improvement on the mechanical properties.

[0090] Table 1 Density and mechanical properties of the comparative examples

[0091]

[0092] The results of the embodiments are shown in Table 2. It can be seen from the data of Comparative Example 2 and Examples 4-6 that pre-ball milling of barium sulfate with fumed silica, vinyl triethoxysilane and titanium dioxide can significantly improve the tensile strength, elongation at break and strap tensile strength of silicone rubber, and the density of silicone rubber is not reduced. This shows that the introduction of the ball milling process has a significant effect on the mechanical properties of silicone rubber. In addition, as the ball milling time is extended in the range of 5-35 minutes, the mechanical properties of silicone rubber are significantly improved; when the ball milling time is 60 minutes, the mechanical properties of silicone rubber are reduced. The results show that when the ball milling time is 5-60 minutes, silicone rubber with high density and good mechanical properties can be obtained. In particular, the preferred ball milling time is 35 minutes.

[0093] Table 2 Density and mechanical properties results of the examples

[0094]

[0095] From the data of Examples 1-4, it can be seen that with the increase of barium sulfate content and ball milling time, the density gradually increases, while the mechanical properties decrease, but the tensile strength can still reach 6MPa. According to prior art reports, the density of silicone rubber is usually 0.8-1.3g / cm 3By adjusting the content of barium sulfate (40-140 g) and the ball milling time (5-60 min), the density of silicone rubber can be made to reach 1.3-1.9 g / cm 3 , while having good mechanical properties.

[0096] The above results show that the introduction of ball milling process has a significant improvement on the mechanical properties of silicone rubber. The present invention can make the density of silicone rubber reach 1.3-1.9g / cm by adjusting the content of barium sulfate and ball milling time. 3 , and has good mechanical properties. In particular, the preferred ball milling time is 35 min.

[0097] Through the above embodiments and experimental examples, it can be seen that the present invention introduces ball milling process and filler to prepare hydrophobic barium sulfate, adds solid silicone rubber to mix, and prepares a silicone rubber strap with high density and good mechanical properties. By adjusting the content of barium sulfate and ball milling time, the density of silicone rubber can reach 1.3-1.9g / cm 3 The density is equivalent to that of fluororubber; the tensile strength is greater than 4MPa. The silicone rubber prepared by the present invention achieves both high density and good mechanical properties, has good texture, and can also be used to prepare silicone rubber straps of different densities according to needs, and has good application prospects.

Claims

1. A high-density silicone rubber filler, characterized in that: It includes the following raw materials in parts by weight: 40-140 parts of barium sulfate, 30-50 parts of silicon dioxide, 5-10 parts of silane coupling agent; The raw materials are ball-milled for 5-60 minutes.

2. The high-density silicone rubber filler according to claim 1, characterized in that: The ball milling time is 5-35 minutes.

3. The high-density silicone rubber filler according to claim 2, characterized in that: The ball milling time was 35 minutes.

4. The high-density silicone rubber filler according to claim 1, characterized in that: The amount of barium sulfate is 140 parts.

5. The high-density silicone rubber filler according to claim 1, characterized in that: The silicon dioxide is fumed silicon dioxide; the silane coupling agent is selected from vinyl triethoxysilane, vinyl tri (2-methoxyethoxy) silane, vinyl triisopropoxy silane, 3- (methacryloyloxy) propyl trimethoxy silane; the raw materials also include 10-30 parts by weight of titanium dioxide.

6. The method for preparing the high-density silicone rubber filler according to any one of claims 1 to 5, characterized in that: The steps include: The barium sulfate is ball-milled with silicon dioxide and a silane coupling agent to obtain the product.

7. A high-density silicone rubber, characterized in that: It includes the following raw materials in parts by weight: 90-210 parts of the high-density silicone rubber filler according to any one of claims 1 to 5, Silicone rubber 80-120 parts, 1-3 parts of vulcanizing agent.

8. The high-density silicone rubber according to claim 7, characterized in that: The silicone rubber is selected from methyl vinyl silicone rubber and methyl silicone rubber, and the vulcanizing agent is selected from dipentadienyl peroxide, dicumyl peroxide and 2,4-di-tert-butylcumyl peroxide.

9. The method for preparing the high-density silicone rubber according to claim 7 or 8, characterized in that: It includes: The high-density silicone rubber filler is mixed with silicone rubber and a vulcanizing agent to obtain the product.

10. Use of the high-density silicone rubber according to claim 7 or 8 in the preparation of sealing materials, shock-absorbing materials, medical devices, and wearable devices.

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