Low-density fluororubber as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fluororubber preparation, and particularly relates to low-density fluororubber and a preparation method and application thereof. Through a screening formula and a preparation process, the fluororubber with low density and good performance and the watchband of the fluororubber are prepared. The density of the prepared fluororubber is as low as 1.6 g / cm < 3 > and is far lower than that of existing fluororubber 1.8 g / cm < 3 >, on the basis that the excellent performance of the fluororubber is maintained, light weight is achieved by reducing the density, meanwhile, the requirements for comfort, durability and appearance of the watchband are met, and the preparation process is simple and convenient, suitable for commercial production and good in application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluororubber preparation, and particularly relates to a low-density fluororubber and its preparation method and use. Background Art

[0002] With the rapid development of the wearable device industry, the market demand for products such as smart watches is increasing continuously, and the materials of watch straps are becoming more diverse. As consumers, when purchasing a smart watch, in addition to paying attention to the functionality of the product, wearing comfort, product durability and stylish appearance are also important factors determining consumer choice, and the wearing experience, appearance effect, durability of the product are inseparable from the choice of materials.

[0003] At present, the strap rubber materials on the market are mainly divided into three types: silicone rubber, thermoplastic polyurethane and fluororubber. Silicone rubber is softer, with poor durability and mechanical properties such as tensile strength and tear strength. Its physical and mechanical properties at room temperature are inferior to most synthetic rubbers; thermoplastic polyurethane has wear resistance, tear resistance and can be quickly formed, and the cost of the finished product is very low, but it has a very strong plastic feeling and general hand feeling, and is mostly used in mobile phone cases, low-price children's watches, etc., and the wearing comfort is also relatively poor; fluororubber is a commonly used raw material for rubber watch straps in the market, with excellent properties such as sweat resistance and aging resistance. The watch strap made of fluororubber has a dense and excellent texture, is soft, skin-friendly, anti-allergic, stain-resistant, comfortable to wear and durable, and can also be formulated into a variety of popular colors, and is favored by smart watches such as Apple Watch, Huami Amazfit, Xiaomi Watch, Huawei (HUAWEI) WATCH GT2, etc.

[0004] However, the density of the fluororubber watch strap is generally 1.9 g / cm 3 , which is too heavy for sports bracelets and watch straps that pursue lightweight. Therefore, it is of great significance to prepare a fluororubber with a low specific gravity that can be used in the field of smart wear, without losing the original durability and appearance requirements of fluororubber. Summary of the Invention

[0005] Aiming at the defects of the prior art, the present invention provides a preparation process of a low-density fluororubber masterbatch, aiming to prepare a fluororubber watch strap with light weight and high durability.

[0006] The present invention provides a low-density fluororubber masterbatch, which comprises the following raw materials in parts by weight:

[0007] 40-60 parts of fluororubber raw rubber, 40-60 parts of mixing-type polyurethane rubber, 2-4 parts of vulcanizing agent, 2-5 parts of accelerator, 15-30 parts of filler;

[0008] The kneaded polyurethane rubber is selected from at least one of kneaded polyester-based polyurethane rubber or kneaded polyether-based polyurethane rubber.

[0009] Preferably, the kneaded polyurethane rubber is selected from at least one of kneaded polyester-based polyurethane rubbers; the kneaded polyester-based polyurethane rubber is selected from at least one of polycaprolactone type, polycarbonate, and polybutylene adipate.

[0010] Preferably, the kneaded polyester-based polyurethane rubber is from Product T2068 of Guangzhou Shunli Polyurethane Technology Co., Ltd.

[0011] Preferably, the fluororubber raw rubber is selected from at least one of type 26, type 246, and type 246 high-fluorine peroxide raw rubber;

[0012] And / or, the filler is selected from at least one or two of diatomaceous earth, sodium aluminosilicate, silica white, barium sulfate, and pigment powder;

[0013] And / or, the vulcanizing agent is selected from at least one of bis(2,5-dimethyl-2,5-di(tert-butylperoxy)hexane) and bis(2,4-dichlorobenzoyl) peroxide; the accelerator is selected from at least one of triallyl isocyanurate, tetramethylthiuram disulfide, trimethylolpropane trimethacrylate, and triallyl cyanurate;

[0014] And / or, the raw material further includes a processing aid, and the processing aid is selected from at least one of palm wax, polyethylene wax, and microcrystalline wax.

[0015] Preferably, the filler is selected from at least one of the following combinations:

[0016] 1) Diatomaceous earth, pigment powder;

[0017] 2) Sodium aluminosilicate, pigment powder;

[0018] 3) Silica white, pigment powder;

[0019] The pigment powder is selected from at least one of titanium dioxide and carbon black; the weight ratio of the diatomaceous earth, sodium aluminosilicate, or silica white to the pigment powder is 4-6:2-4.

[0020] Preferably, the low-density fluororubber kneaded compound is prepared by the following preparation method:

[0021] Plasticize the fluororubber raw rubber and the kneaded polyurethane rubber, and add an accelerator, a filler, and a vulcanizing agent for kneading to obtain the product.

[0022] The present invention provides a preparation method of the low-density fluororubber kneaded compound described in any one of the above, and the preparation method includes the following steps:

[0023] The fluororubber raw rubber and the kneaded polyurethane rubber are plastisized, and a promoter, a filler and a vulcanizing agent are added for kneading to obtain the product.

[0024] The present invention provides a low-density fluororubber, which is prepared from the low-density fluororubber kneaded rubber described above.

[0025] The present invention provides a preparation method of a low-density fluororubber. The preparation method includes the following steps: reacting the low-density fluororubber kneaded rubber under the conditions of a pressure of 14-18 MPa and a temperature of 150-180 °C for 3-15 min to obtain the product.

[0026] The present invention provides the use of the low-density fluororubber kneaded rubber described in any one of the above, or the low-density fluororubber described above in the preparation of wearable devices.

[0027] The term "kneading" is a term in rubber preparation and processing, which refers to mixing and plastisizing raw rubber with various compounding agents (such as vulcanizing agents, fillers, promoters, plasticizers, antioxidants, etc.) in specific equipment, and the specific equipment includes an open mill.

[0028] Through screening the formula and preparation process, the present invention prepares a fluororubber kneaded rubber and its watch band that take into account both low density and good performance. The density of the fluororubber prepared by the present invention is as low as 1.6 g / cm 3 , which is much lower than the density of the existing fluororubber, 1.8 g / cm 3 . On the basis of maintaining the excellent performance of the fluororubber, lightweight is achieved by reducing the density, and at the same time, the comfort, durability and appearance requirements of the watch band are met. Moreover, the preparation process is simple, suitable for commercial production, and has good application prospects.

[0029] Obviously, based on the above content of the present invention, according to the common general knowledge and conventional means in the art, without departing from the above basic technical idea of the present invention, various other forms of modifications, substitutions or changes can also be made.

[0030] The following is a further detailed description of the above content of the present invention through specific embodiments in the form of examples. However, this should not be understood as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention belong to the scope of the present invention. Specific Embodiments

[0031] In the following examples and experimental examples, the reagents and materials not specifically described are all commercially available products.

[0032] Fluororubber raw rubber: 246M of Shandong Huaxia Shenzhou New Materials Co., Ltd.;

[0033] Promoter: LANXESS of Germany TAIC / S;

[0034] Curing agent: Arkema 101XL45-SP2 double 25;

[0035] Hollow microspheres: 3M hollow glass microspheres S60HS;

[0036] Silicone rubber: Dongjue Silicone Group Co., Ltd. 110 methyl vinyl silicone rubber

[0037] Example 1 A low-density fluororubber compound and its strap

[0038] The low-density fluororubber compound and the strap thereof of the present embodiment are prepared by the following method:

[0039] (1) Preparation of rubber compound

[0040] First, 50g of fluororubber raw rubber and 50g of mixed polyester polyurethane rubber were added to a double-roll open mill, fully plasticized at room temperature, and then the roller distance was reduced so that excess rubber was accumulated on the rollers, 17g of diatomaceous earth, 10g of titanium dioxide, and 3g of accelerator were added, and finally 2.5g of vulcanizing agent was added for uniform mixing. After uniform mixing, the roller distance was adjusted to less than 1mm, and the rollers were wrapped, 6 triangular thin passes were made and rolled, and finally the roller distance was adjusted to 2mm to produce a sheet to obtain a mixed rubber. The mixed polyester polyurethane used in this embodiment is produced by Guangzhou Shunli Polyurethane Technology Co., Ltd. T2068 products;

[0041] (2) Preparation of watch strap

[0042] The mixed rubber is preformed and cut into strips and then placed in a mold. It is vulcanized for 10 minutes at a pressure of 16 MPa and a temperature of 170°C to obtain the product.

[0043] The density of the fluororubber strap prepared by the method of this embodiment is 1.60 g / cm 3 , good durability.

[0044] In other embodiments, when preparing the rubber mixture, processing aids such as palm wax, polyethylene wax or microcrystalline wax may be added to further improve the processing performance and durability of the strap.

[0045] In other embodiments, the compounded polyester type polyurethane rubber may be replaced by a compounded polyether type polyurethane rubber, which may achieve similar density and durability as those of the present embodiment.

[0046] Example 2 A low-density fluororubber compound and its strap

[0047] The fluororubber compound and its watch strap were prepared according to the method of Example 1, except that the titanium dioxide was replaced with carbon black. The density of the fluororubber watch strap prepared by the method of this example was 1.58 g / cm3 , with good durability.

[0048] Example 3 A low-density fluororubber compound and its watch strap

[0049] Prepare the fluororubber compound and its watch strap according to the method of Example 1, except that: replace diatomaceous earth with sodium aluminosilicate. The density of the fluororubber watch strap prepared by the method of this example is 1.60 g / cm 3 , with good durability.

[0050] Example 4 A low-density fluororubber compound and its watch strap

[0051] Prepare the fluororubber compound and its watch strap according to the method of Example 1, except that: the blended polyester-type polyurethane used is a kind of American TSE blended polyurethane rubber, with the model of Millathane 66. The fluororubber watch strap prepared by the method of this example has the same density and durability as that of Example 1.

[0052] Example 5 A low-density fluororubber compound and its watch strap

[0053] Prepare the fluororubber compound and its watch strap according to the method of Example 1, except that: the blended polyester-type polyurethane used is Urepan 640G (raw rubber) of German Rhein Chemie. The fluororubber watch strap prepared by the method of this example has the same density and durability as that of Example 1.

[0054] Comparative Example 1

[0055] Prepare the fluororubber compound and its watch strap according to the method of Example 1, except that: the fluororubber raw rubber is 100 g, and the blended polyester-type polyurethane rubber is not added.

[0056] Comparative Example 2

[0057] Prepare the fluororubber compound and its watch strap according to the method of Example 1, except that: the fluororubber raw rubber is 100 g; the blended polyester-type polyurethane rubber is not added; diatomaceous earth is replaced by hollow microspheres.

[0058] Comparative Example 3

[0059] Prepare the fluororubber compound and its watch strap according to the method of Example 1, except that: the blended polyester-type polyurethane rubber is replaced by silicone rubber.

[0060] The technical solution of the present invention will be further described through experiments below. The samples detected in the following experimental examples are prepared by the methods of Examples 1-3 and Comparative Examples 1-3.

[0061] Experimental Example 1 Performance study of modified fluororubber watch straps

[0062] I. Experimental Methods

[0063] The fluororubber watchband compound was prepared according to the methods of Examples 1-3 and Comparative Examples 1-3 respectively. After pre-forming the compound into sheets, it was placed in a mold and vulcanized for 10 min under the conditions of a pressure of 16 MPa and a temperature of 170 °C. Its hardness, density, tensile strength, elongation at break, tear strength and watchband tensile resistance were tested. The test methods for relevant indicators are as follows:

[0064] Hardness: GB / T 531.1-2008 "Rubber, vulcanized or thermoplastic - Determination of indentation hardness - Part 1: Shore hardness";

[0065] Density: GB / T 533-2008 "Rubber, vulcanized or thermoplastic - Determination of density";

[0066] Tensile strength: GB / T 528-2009 "Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties";

[0067] Elongation at break: GB / T 528-2009 "Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties";

[0068] Tear strength: GB / T 529-2008 "Rubber, vulcanized or thermoplastic - Determination of tear strength (trouser, right angle and crescent specimens)";

[0069] Watchband tensile resistance: Standard watch case, watchband, watch buckle and spring bar were equipped. The index was 80 N for 5 s, once; with a tensile meter and related jigs, the test speed from the natural state to when the watchband started to be stressed was 30 mm / min. For the long watchband, the spring bar was pushed to fasten the 5th hole buckle. The result was the magnitude of the force when it was broken.

[0070] II. Experimental Results

[0071] 1. Screening of Composite Additives

[0072] The experimental results are shown in Table 1. From the data of Example 1, Comparative Example 1 and 3 in the table, it can be seen that in Comparative Example 1, without using the composite additive and all the raw rubber being fluororubber raw rubber, the density of the compound was 1.97 g / cm 3 , much higher than 1.6 g / cm 3 ; in Comparative Example 3, when using silicone rubber with a relatively light self-weight as the composite additive, the density decreased to 1.62 g / cm 3 , but the tensile strength, tear strength and watchband tensile resistance all decreased significantly, indicating that when the composite additive was silicone rubber, although the density was reduced, its durability decreased; in Example 1, when choosing the compounded polyester-type polyurethane rubber as the composite additive, the density decreased to 1.62 g / cm3 Moreover, the tensile strength, elongation at break, tear strength and strap tensile resistance not only do not decrease, but are improved instead. In particular, the elongation at break is significantly improved. Therefore, when the composite additive is preferably a kneaded polyester-based polyurethane rubber, the density is reduced while the durability of the fluororubber is improved, meeting the requirements of the fluororubber strap.

[0073] Table 1

[0074]

[0075] (2) Screening of fillers

[0076] The experimental results are shown in Table 2. It can be seen from the data of Example 1, 3 and Comparative Example 2 in the table that in Comparative Example 2, hollow glass microspheres were tried to increase the volume and reduce the density, but it can be seen that the effect on density reduction is small and cannot effectively meet the requirement of low density; in Example 3, sodium aluminosilicate is a filler with stronger self-reinforcement, but when used in the base material of low-density fluororubber, it is found that its effect on increasing the strength of the kneaded rubber is small, and it is not as obvious as the effect of diatomaceous earth used in Example 1. Therefore, when the filler is any one of diatomaceous earth and sodium aluminosilicate, the requirements of low density and durability can be met. In particular, the performance of diatomaceous earth is better.

[0077] Table 2

[0078]

[0079]

[0080] (3) Change of color

[0081] The results are shown in Table 3. It can be seen from the data of Example 1 and 2 that by changing the color of the color powder, the color of the kneaded rubber can be adjusted. At the same time, the hardness, tensile properties, tear properties and strap tensile properties are not significantly reduced. It shows that the kneaded rubber prepared by the present invention has strong practicability, and colored kneaded rubber meeting the requirements of low density and good performance can be prepared by adding or adjusting the color powder.

[0082] Table 3

[0083] Example 1 Example 2 Toner Titanium Dioxide Carbon Black Hardness (Shore A) 63 65 <![CDATA[Density (g / cm 3 )]]> 1.60 1.58 Tensile Strength (MPa) 21 23 Elongation at Break (%) 440 380 Tear Strength (KN / m) 34 38 Tensile Resistance of Watch Band (N) 110 125

[0084] The above results show that the present invention uses peroxy fluororubber as the base material, adds kneaded polyurethane as an additive, and preferably uses diatomaceous earth or sodium aluminosilicate as the filler to prepare a low-density 1.6 g / cm 3 rubber material, which breaks the lowest density of fluororubber wearable material of 1.8 g / cm 3Due to these limitations, the watch strap made of the mixed rubber can not only meet the requirements of comfort, skin-friendliness, feel, etc. for smart wearable products, but also has no cell stimulation or sensitization hazards, filling the gap in existing low-density fluororubber raw materials.

[0085] As can be seen from the above embodiments and experimental examples, the present invention prepares a fluororubber watch strap with both low density and good performance by screening the formula and preparation process. The density of the fluororubber prepared by the present invention is as low as 1.6 g / cm 3 , far lower than the density of existing fluororubber, which is 1.8 g / cm 3 . On the basis of maintaining the excellent performance of fluororubber, lightweight is achieved by reducing the density, while meeting the comfort, durability and appearance requirements of the watch strap. Moreover, the preparation process is simple, suitable for commercial production, and has good application prospects.

Claims

1. A low-density fluororubber compound, characterized in that: It includes the following raw materials in parts by weight: 40-60 parts of fluororubber raw rubber, 40-60 parts of mixed polyurethane rubber, 2-4 parts of vulcanizing agent, 2-5 parts of accelerator, 15-30 parts of filler; The kneaded polyurethane rubber is selected from at least one of kneaded polyester polyurethane rubber and kneaded polyether polyurethane rubber.

2. The low-density fluororubber compound according to claim 1, characterized in that: The mixed polyurethane rubber is selected from at least one of mixed polyester polyurethane rubbers; the mixed polyester polyurethane rubber is selected from at least one of polycaprolactone, polycarbonate, and polybutylene adipate.

3. The low-density fluororubber compound according to claim 1 or 2, characterized in that: The mixed polyester polyurethane rubber is selected from Guangzhou Shunli Polyurethane Technology Co., Ltd. T2068 product.

4. The low-density fluororubber compound according to claim 1, characterized in that: The fluororubber raw rubber is selected from at least one of 26-type, 246-type, and 246-type high-fluorine peroxide raw rubber; And / or, the filler is selected from at least one or two of diatomaceous earth, sodium aluminum silicate, white carbon, barium sulfate, and pigment powder; And / or, the vulcanizing agent is selected from at least one of bis(2,5-dimethyl-2,4 ... And / or, the raw material further includes a processing aid, and the processing aid is selected from at least one of palm wax, polyethylene wax, and microcrystalline wax.

5. The low-density fluororubber compound according to claim 4, characterized in that: The filler is selected from at least one of the following combinations: 1) Diatomaceous earth, pigment powder; 2) Sodium aluminum silicate, pigment powder; 3) White carbon black, pigment powder; The pigment powder is selected from at least one of titanium dioxide and carbon black; the weight ratio of diatomaceous earth, sodium aluminum silicate or white carbon black to the pigment powder is 4-6:2-4.

6. The low-density fluororubber compound according to claim 1, characterized in that: Prepared according to the following preparation method: The fluororubber raw rubber and the mixing type polyurethane rubber are plasticized, and then an accelerator, a filler and a vulcanizing agent are added and mixed to obtain the product.

7. The method for preparing the low-density fluororubber compound according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: The fluororubber raw rubber and the mixing type polyurethane rubber are plasticized, and then an accelerator, a filler and a vulcanizing agent are added and mixed to obtain the product.

8. A low-density fluororubber, characterized in that: It is made from the low-density fluororubber compound described in claim 1.

9. The method for preparing the low-density fluororubber according to claim 8, characterized in that: The preparation method comprises the following steps: reacting the low-density fluororubber compound rubber for 3 to 15 minutes under the conditions of a pressure of 14 to 18 MPa and a temperature of 150 to 180° C. to obtain the compound.

10. Use of the low-density fluororubber compound according to any one of claims 1 to 6, or the low-density fluororubber according to claim 8 in the preparation of wearable devices.

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