Fluororubber having high elongation and method for producing the same

Abstract

The present application relates to the technical field of rubber, in particular to a fluorine rubber with high elongation and a preparation method thereof. The fluorine rubber with high elongation is prepared from the following raw materials in parts by weight: fluorine raw rubber 80-100 parts, vulcanizing agent 1.2-1.8 parts, reinforcing agent 20-25 parts, accelerator 0.3-0.6 parts, internal release agent 2.5-3.5 parts and composite additive 10-20 parts; the composite additive is compounded from magnesium oxide, calcium hydroxide and organosiloxane. The elongation of the formula is much higher than that of ordinary bisphenol vulcanized fluorine rubber, even exceeds that of fluorine rubber with added white carbon black formula, and can be comparable to the elongation at break of ternary glue. Since white carbon black is not added in the raw materials or ternary glue is used, the low-pressure deformation performance characteristics of the pure binary bisphenol system are greatly exerted. The rubber compound does not have the phenomenon of sticking to the roller during sheeting, has good flexibility, is not easy to adhere between adjacent rubber sheets, and is convenient for production and processing. The addition of the composite additive in the raw materials can make the adhesive reaction of the rubber compound and the skeleton more sufficient, and the adhesion is better.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber, in particular to a fluororubber with high elongation and a preparation method thereof. BACKGROUND

[0002] The fluororubber of a binary bisphenol vulcanization system has excellent mechanical strength and thermal stability, and is widely used in the fields of automobiles, machinery, chemical industry, aviation and the like. However, the uniform characteristic of the fluororubber of the binary bisphenol vulcanization system is that the elongation at break is low. In particular, the filler used in the colored fluororubber is mostly white filler such as calcium silicate and diatomite, which only has reinforcing effect and does not improve the elongation at break. On the contrary, the elongation at break tends to decrease. At present, the elongation at break of the colored fluororubber of the binary bisphenol vulcanization system can only be maintained at 180-200%. However, with the development of the economy and society, people have higher and higher requirements for the performance of automobiles, and consequently, higher and higher requirements for automobile parts, especially complex automobile working conditions and harsh material performance requirements. The elongation at break is one of the more important test performances of automobile materials.

[0003] In the prior art, there are two methods for improving the elongation at break of the common colored fluororubber: 1. Adding white carbon black to the formula to improve the elongation at break. However, the addition of white carbon black at least has two problems in process and performance. In terms of process, the compatibility of white carbon black with fluororubber is generally poor, and white carbon black is prone to migrate to the surface of the rubber, resulting in serious roll sticking of the rubber during sheeting on the open mill. In addition, the rubber sheets are prone to adhere to each other after sheeting, which affects the production operability. In terms of performance, the addition of white carbon black seriously affects the compression set performance of the rubber, especially for cylinder gaskets and O-rings which have high compression set requirements. Therefore, the method of adding white carbon black to the formula to improve the elongation at break of the colored fluororubber is greatly limited. 2. Adding a ternary bisphenol vulcanization system (which has better elongation at break than the binary bisphenol vulcanization system) to the binary bisphenol vulcanization system to improve the overall elongation at break. However, the addition of the ternary bisphenol vulcanization system also has two problems in process and performance. In terms of process, since the two bisphenol vulcanization systems are not of the same type, the rubber is prone to compatibility problems in actual production, resulting in layering on the surface of the product. In addition, since the ternary bisphenol vulcanization system contains a tetrafluoroethylene group, it is prone to poor adhesion between the rubber and the skeleton in products with skeleton adhesion requirements, which affects the performance of the product. In terms of performance, the compression set performance of the ternary bisphenol vulcanization system is not as good as that of the binary bisphenol vulcanization system, and the addition of the ternary bisphenol vulcanization system also reduces the compression set performance of the rubber.

[0004] In summary, it is of great significance and far-reaching to develop a new process and formula technology to improve the elongation at break of the fluororubber of the binary bisphenol vulcanization system. SUMMARY

[0005] The main object of the present application is to provide a method for preparing fluorine rubber with high elongation, aiming to improve the low elongation at break of the existing fluorine rubber, and the technical problem that the method for improving the elongation at break of fluorine rubber in the prior art easily leads to the reduction of the compression set performance and product quality of fluorine rubber.

[0006] To achieve the above object, the present application provides a fluorine rubber with high elongation, which is prepared from the following raw materials in parts by weight: fluorine raw rubber 80-100 parts, vulcanizing agent 1.2-1.8 parts, reinforcing agent 20-25 parts, accelerator 0.3-0.6 parts, internal release agent 2.5-3.5 parts, and composite additive 10-20 parts; the composite additive is compounded from magnesium oxide, calcium hydroxide and organosiloxane.

[0007] The present application introduces a composite additive, organosiloxane (which can be WS280P in actual use), which is not used in ordinary rubber formulations, and a compound of magnesium oxide and calcium hydroxide into the formulation. The composite additive and the vulcanization system (vulcanizing agent, accelerator) balance each other and produce a synergistic effect. In particular, the organosiloxane is introduced as a carrier to form a bridge and a "channel", forming a high activity point between magnesium oxide and calcium hydroxide, which can be grafted to the molecular chain during the crosslinking process of fluorine rubber, improve the flexibility of the rubber molecular chain, make the rubber more flexible in macroscopic, and thus improve the elongation at break, thereby greatly improving the elongation at break performance of the fluorine rubber. Moreover, the rubber compound prepared by using the above formulation and weight design can greatly improve the processing performance and production process performance of the material, and obtain fluorine rubber with high quality.

[0008] Preferably, the mass ratio of the magnesium oxide, the calcium hydroxide and the organosiloxane is 6-7:3-5:3-6. In the formulation of the composite additive, magnesium oxide and calcium hydroxide mainly act as acid absorbents to adjust the acidity and alkalinity in the formulation, thereby changing the vulcanization speed, but they do not have the functions of bridging and forming a "channel" and cannot improve the flexibility of the molecular chain. The organosiloxane-WS280P is commonly used in the prior art for plasticizing acrylate rubber ACM and ethylene acrylate rubber AEM, and only plays a role in improving the processing performance. However, in the present application, by using the above mass ratio 6-7:3-5:3-6 of magnesium oxide, calcium hydroxide and organosiloxane in combination with the following preparation process, the composite additive is prepared by high-speed stirring pretreatment in a stirrer, and then added to the fluorine rubber, which can greatly improve the elongation at break performance of the rubber.

[0009] Preferably, the mass ratio of the magnesium oxide, the calcium hydroxide and the organosiloxane is 7:4:4, at which the improvement effect on the elongation at break of the rubber is best.

[0010] Preferably, the fluoroelastomer is a dual bisphenol curing system fluoroelastomer, the vulcanizing agent is bisphenol AF, and the accelerator is benzyl triphenyl phosphonium chloride. The use of the cost-effective low-pressure bisphenol dual curing system fluoroelastomer can greatly improve the processability of the material.

[0011] Preferably, the reinforcing agent comprises at least one of calcium silicate or diatomite; or the reinforcing agent is a mixture of calcium silicate and diatomite in a mass ratio of 15:10. The reinforcing agent can be selected from one of calcium silicate or diatomite, or can be compounded from calcium silicate or diatomite. By adjusting the types and proportions of calcium silicate and diatomite, the mechanical properties of the fluoroelastomer can be improved.

[0012] Preferably, the internal release agent is a mixture of palm wax and high molecular alcohol ester compounds in a mass ratio of 5:5. Fluoroelastomer raw rubber is prone to sticking to the roll during mixing. During the production of vulcanization, due to the poor hot tear resistance of the fluoroelastomer itself, cracks are prone to occur during demolding. Therefore, in order to improve the processability of the fluoroelastomer, a flow aid and an internal release agent for assisting product demolding are added to the formula. The flow aid includes palm wax and high molecular alcohol ester compounds-FPA. The mass ratio in the above-mentioned compound formula is better for improving the processability of the fluoroelastomer.

[0013] Preferably, the raw material of the fluoroelastomer further comprises 2-4 parts of a pigment aid, and the pigment aid is iron red. The color aid is mainly used to change the final color of the fluoroelastomer, and the color is adjusted according to the required color of the fluoroelastomer. Common color aids can be iron red, phthalocyanine green, etc.

[0014] In addition, the application also provides a preparation method of the fluoroelastomer with high elongation.

[0015] S1. The raw materials of the composite aid are mixed in proportion and stirred uniformly, and then added to a mold for compression molding to obtain the composite aid;

[0016] S2. The fluoroelastomer raw rubber is first plasticized, and then the reinforcing agent, the internal release agent, the pigment aid, and the composite aid are added and continuously mixed to obtain the fluoroelastomer raw rubber.

[0017] S3. After the triangle bag is punched, the fluoroelastomer raw rubber is thin-passed again, and then the fluoroelastomer with high elongation is obtained.

[0018] The preparation method of the fluoroelastomer is simple, the composite aid is prepared first, the fluoroelastomer raw rubber is plasticized, and then the reinforcing agent, the internal release agent, and the composite aid are mixed to obtain the fluoroelastomer raw rubber. The preparation of the raw material has low cost, and the obtained fluoroelastomer has good tear rate, pressure change performance, and excellent appearance quality.

[0019] Preferably, in step S1, the stirring temperature is 60-75 DEG C, and the time is 6-7 min. The composite auxiliary is first stirred in a blender at high speed, and is pretreated for 6-7 min. The composite auxiliary prepared by the above pretreatment is added to the fluoroelastomer prepared from the fluoroelastomer raw material, and the fluoroelastomer has better performance.

[0020] Preferably, in step S2, the mastication temperature of the fluoroelastomer raw material is 80-90 DEG C, and the time is 1-1.5 min; and the temperature of the internal mixer is 90-110 DEG C, and the time is 7-8 min.

[0021] Preferably, in step S2, the discharge temperature of the fluoroelastomer is 120-130 DEG C. Under the above formula system of the fluoroelastomer, the discharge temperature is controlled to be 120-130 DEG C, and the fluoroelastomer has better performance.

[0022] Compared with the prior art, the fluoroelastomer with high elongation has the following beneficial effects:

[0023] 1. High elongation at break: the elongation of the formula is much higher than that of ordinary bisphenol vulcanized fluoroelastomer, and even exceeds that of the fluoroelastomer with added white carbon black, and can be comparable to the elongation at break of the ternary rubber.

[0024] 2. Good pressure change performance: since the white carbon black is not added in the raw material or the ternary rubber is used, the low pressure change performance characteristics of the pure binary bisphenol system are greatly exerted, and the fluoroelastomer has good pressure change performance.

[0025] 3. Good process performance: the rubber has no roll sticking phenomenon in the sheeting process, has good flexibility, and is not easy to adhere between adjacent rubber sheets, and is convenient for production and processing.

[0026] 4. Good adhesion performance of the rubber and the skeleton: the addition of the composite auxiliary does not cause the adhesion of the rubber and the skeleton to be poor as when the ternary rubber is used, but makes the adhesion effect of the rubber and the skeleton better. This is mainly because the filler is treated more finely in the stirring process, the activity of the effective factor is improved, the adhesion of the rubber and the skeleton is more sufficient, and the adhesion is better. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other related drawings can be obtained without creating laborious.

[0028] Fig. 1 The actual picture of the fluoroelastomer of the present application embodiment 2 when mixing in the open mill;

[0029] Fig. 2 This is a photograph of the fluororubber of Comparative Example 3 in this scheme being mixed on an open mill.

[0030] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0033] A method for preparing fluororubber with high elongation includes the following steps:

[0034] S1. The raw materials of the composite additive are mixed in proportion, stirred evenly in a mixer, and then pressed into a custom mold to obtain the composite additive; wherein, the stirring temperature is 60-75℃ and the time is 6-7min; usually, the pressed composite additive needs to be left to stand for about 2 days before it can be used.

[0035] S2. The fluoropolymer is first plasticized in a mixing chamber, then the reinforcing agent, the internal release agent, and the composite additive are added and the mixing continues. The rubber is discharged and passed through a two-roll mill. Then the vulcanizing agent and the accelerator are added and mixed evenly. The plasticizing temperature of the fluoropolymer is 80-90℃ for 1-1.5 minutes. The temperature is raised to 90-110℃ and the mixing continues for 7-8 minutes. The discharge temperature is 120-130℃. After passing through a two-roll mill 3-4 times, the vulcanizing agent and the accelerator are added, and the two-roll mill is used for shearing.

[0036] S3. After forming triangular wraps, the material undergoes thin-pass processing. After sheeting, samples are prepared. Once the samples pass inspection, production can begin to obtain the fluororubber with high elongation. Approximately 10 triangular wraps are formed.

[0037] The fluoro-rubber with high elongation is prepared by using the following raw materials in parts by weight: fluoro-rubber 80-100 parts, vulcanizing agent 1.2-1.8 parts, reinforcing agent 20-25 parts, accelerator 0.3-0.6 parts, internal release agent 2.5-3.5 parts and composite auxiliary agent 10-20 parts; wherein, the raw materials can further include pigment auxiliary agent 2-4 parts.

[0038] The mass ratio of the raw rubber to the composite auxiliary agent can be about (5-80):1.

[0039] The composite auxiliary agent is compounded by magnesium oxide, calcium hydroxide and organosiloxane, and the mass ratio of the magnesium oxide, the calcium hydroxide and the organosiloxane is 6-7:3-5:3-6.

[0040] The fluoro-rubber is bisphenol vulcanization system fluoro-rubber, the reinforcing agent includes at least one of calcium silicate or diatomite, or the reinforcing agent is mixed by calcium silicate and diatomite at a mass ratio of 15:10, the vulcanizing agent is bisphenol AF, the accelerator is benzyl triphenyl phosphonium chloride, the internal release agent is mixed by palm wax and macromolecular alcohol ester compound at a mass ratio of 5:5, and the pigment auxiliary agent is iron red.

[0041] The technical solutions of the present application are further described in detail in combination with specific embodiments, and it should be understood that the following embodiments are only used to explain the present application and not to limit the present application.

[0042] The model and source of the main raw materials used in the following examples and comparative examples are as follows:

[0043]

[0044] Example 1

[0045] A preparation method of a fluoro-rubber with high elongation includes the following steps:

[0046] S1. The magnesium oxide, the calcium hydroxide and the organosiloxane are mixed at a mass ratio of 6:3:6, then stirred uniformly in a stirring machine, and then added into a customized mold for compression molding to obtain the composite auxiliary agent; wherein, the stirring temperature is 65℃, and the time is 6min;

[0047] S2. 83 parts of fluoro-rubber are first plasticized in a mixing chamber at a plasticizing temperature of 84℃ for 1min; then 23 parts of reinforcing agent, 2.6 parts of internal release agent, 2 parts of pigment auxiliary agent and 16 parts of composite auxiliary agent are added, and the temperature is increased to 96℃ for further mixing for 7min; the rubber is discharged and thin passed on an open mill for 3 times, wherein the discharge temperature is 125℃; then 1.2 parts of vulcanizing agent and 0.6 parts of accelerator are added and mixed uniformly, and the roller of the open mill is sheared at the same time.

[0048] S3. After making about 10 triangle bags, thin pass is carried out, and the fluororubber with high elongation is obtained after sheeting.

[0049] The reinforcing agent is calcium silicate; and the internal release agent is palm wax.

[0050] Example 2

[0051] A preparation method of a fluororubber with high elongation comprises the following steps:

[0052] S1. Magnesium oxide, calcium hydroxide and organosiloxane are mixed in a mass ratio of 7:4:4, and then stirred uniformly in a blender, and then added into a customized mold for compression molding to obtain the composite aid; wherein the stirring temperature is 75 DEG C, and the time is 6 min;

[0053] S2. 100 parts of fluorine raw rubber are plasticized in a mixing chamber, the plasticizing temperature is 80 DEG C, and the time is 1.5 min; then 25 parts of reinforcing agent, 3 parts of internal release agent, 3 parts of pigment aid and 10 parts of composite aid are added, and the temperature is increased to 100 DEG C for further mixing, and the time is 8 min; the rubber is discharged and thin passed for 3 times on an open mill, wherein the discharge temperature is 120 DEG C; then 1.5 parts of vulcanizing agent and 0.4 parts of accelerator are added and mixed uniformly, and the roller of the open mill is sheared at the same time;

[0054] S3. After making about 10 triangle bags, thin pass is carried out, and the fluororubber with high elongation is obtained after sheeting.

[0055] The reinforcing agent is obtained by mixing calcium silicate and diatomite in a mass ratio of 3:2; and the internal release agent is obtained by mixing palm wax and FPA in a mass ratio of 1:1.

[0056] Example 3

[0057] A preparation method of a fluororubber with high elongation comprises the following steps:

[0058] S1. Magnesium oxide, calcium hydroxide and organosiloxane are mixed in a mass ratio of 7:5:3, and then stirred uniformly in a blender, and then added into a customized mold for compression molding to obtain the composite aid; wherein the stirring temperature is 70 DEG C, and the time is 7 min;

[0059] S2. 92 parts of fluorine raw rubber are plasticized in a mixing chamber, the plasticizing temperature is 90 DEG C, and the time is 1 min; then 20 parts of reinforcing agent, 2.5 parts of internal release agent, 4 parts of pigment aid and 20 parts of composite aid are added, and the temperature is increased to 110 DEG C for further mixing, and the time is 7 min; the rubber is discharged and thin passed for 3 times on an open mill, wherein the discharge temperature is 130 DEG C; then 1.8 parts of vulcanizing agent and 0.5 parts of accelerator are added and mixed uniformly, and the roller of the open mill is sheared at the same time;

[0060] S3. After making about 10 triangular bags, thin pass is performed, and the fluororubber with high elongation is obtained after sheeting.

[0061] The reinforcing agent is mixed by calcium silicate and diatomite with a mass ratio of 3:2; the internal release agent is mixed by palm wax and FPA with a mass ratio of 1:1.

[0062] Comparative Example 1

[0063] In the present comparative example, the type and source of each raw material are consistent with those of Example 2, and the only difference is that white carbon black is used for reinforcement in the formula, and the following raw materials are included in the formula by weight: binary bisphenol vulcanization system fluorine rubber 100 parts, vulcanizing agent 1.6 parts, reinforcing agent 10 parts, white carbon black 10 parts, accelerator 0.6 parts, internal release agent 1.8 parts, magnesium oxide 6 parts, calcium hydroxide 3 parts, and pigment additive 3 parts. The preparation process is consistent with that of Example 2, but there is no preparation step of composite additive (i.e. no step S1).

[0064] Comparative Example 2

[0065] In the present comparative example, the type and source of each raw material are consistent with those of Example 2, and the only difference is that white carbon black is used for reinforcement in the formula, and the following raw materials are included in the formula by weight: binary bisphenol vulcanization system fluorine rubber 100 parts, vulcanizing agent 1.6 parts, reinforcing agent 10 parts, white carbon black 10 parts, accelerator 0.6 parts, internal release agent 1.8 parts, magnesium oxide 6 parts, calcium hydroxide 3 parts, and pigment additive 3 parts. The preparation process is consistent with that of Example 2, but there is no preparation step of composite additive (i.e. no step S1).

[0066] Comparative Example 3

[0067] In the present comparative example, the type and source of each raw material are consistent with those of Example 2, and the only difference is that white carbon black is used for reinforcement in the formula, and the following raw materials are included in the formula by weight: binary bisphenol vulcanization system fluorine rubber 100 parts, vulcanizing agent 1.6 parts, reinforcing agent 10 parts, white carbon black 10 parts, accelerator 0.6 parts, internal release agent 1.8 parts, magnesium oxide 6 parts, calcium hydroxide 3 parts, and pigment additive 3 parts. The preparation process is consistent with that of Example 2, but there is no preparation step of composite additive (i.e. no step S1).

[0068] Comparative Example 4

[0069] In the present comparative example, the type and source of each raw material are consistent with those of Example 2, and the only difference is that white carbon black is used for reinforcement in the formula, and the following raw materials are included in the formula by weight: binary bisphenol vulcanization system fluorine rubber 100 parts, vulcanizing agent 1.6 parts, reinforcing agent 10 parts, white carbon black 10 parts, accelerator 0.6 parts, internal release agent 1.8 parts, magnesium oxide 6 parts, calcium hydroxide 3 parts, and pigment additive 3 parts. The preparation process is consistent with that of Example 2, but there is no preparation step of composite additive (i.e. no step S1).

[0070] The fluororubber prepared in Examples 1-3 and Comparative Examples 1-4 was subjected to performance testing, and the specific test results are shown in the following table:

[0071]

[0072]

[0073] From the above table, as the test results of Examples 1-3, the fluororubber prepared by the present scheme has higher elongation at break, the hardness is above 72, the tensile strength is above 12 MPa, and the compression set performance of the fluororubber is also relatively excellent, there is no phenomenon of sticking to the roller during the processing, and the finished fluororubber product also does not have the phenomenon of delamination.

[0074] From the test results of Example 2 and Comparative Example 1, the data of Example 2 is close to that of Comparative Example 1 except for the compression set, but the compression set performance of Comparative Example 1 is obviously worse than that of Example 2, Example 1 does not stick to the roller, and the surface of the finished product is not delaminated, while Comparative Example 1 has a serious sticking to the roller. From the test results of Example 2 and Comparative Example 2, the data of Example 2 is close to that of Comparative Example 2 except for the compression set, but the compression set of Comparative Example 2 is obviously worse than that of Example 2, Example 2 does not stick to the roller, and the surface of the finished product is not delaminated, while the surface of the finished product of Comparative Example 2 has delamination. From the test results of Example 2 and Comparative Examples 3-4, due to the addition of white carbon black, the elongation at break of the fluororubber is obviously improved, but the elasticity of the finished fluororubber product is poor, and the compression set performance is also obviously reduced. As shown in Table 5, the fluororubber of Example 2 has good roller wrapping performance during production, the surface of the rubber compound is smooth, and there is no sticking to the roller, while Comparative Example 3 has a rough surface due to the addition of white carbon black, and the white carbon black is easy to migrate to the surface of the rubber, which makes the rubber compound easy to stick to the roller, resulting in poor sheeting process of the rubber compound. Figs. 1-2

[0075] Example 5

[0076] The parameters and preparation steps of the present example are consistent with those of Example 2, and the only difference is that the mass ratio of magnesium oxide, calcium hydroxide and organosiloxane in the raw materials of the composite additive is different, as shown in the following table:

[0077]

[0078]

[0079] Comparative Example 5

[0080] The parameters and preparation steps of the present example are consistent with those of Example 2, and the only difference is that the organosiloxane is not added in the raw materials of the composite additive, and the specific mass ratio is shown in the following table:

[0081]

[0082] The fluororubber prepared by Example 5 and Comparative Example 5 is subjected to performance testing, and the specific test results are shown in the following table:

[0083]

[0084] ​From the above table, as the detection results of example 2 and comparative example 5, the hardness, tensile strength, elongation at break and compression set of example 2 are better than those of comparative example 5, because when WS280P is introduced into the composite auxiliary as a carrier, it forms a high activity point between magnesium oxide and calcium hydroxide, which can graft to the molecular chain during the crosslinking process of fluorine rubber, improve the flexibility of the rubber molecular chain, make the rubber more flexible in macroscopic, and further improve the elongation at break and other properties.

[0085] From the detection results of example 2 and example 5, the elongation at break of example 5-1 is not significantly improved, because the mass ratio of calcium hydroxide to magnesium oxide is larger, although it can improve the compression set, but it is easy to lead to too large crosslinking density and further reduce the elongation at break. While in example 5-2 to 5-3 and example 2, due to the reasonable ratio of magnesium oxide and calcium hydroxide, plus the bridging and "channel" effect of WS280P, the mutual cooperation of the three produces a positive coordination effect, the elongation at break is obviously improved, especially in example 2, the mass ratio of magnesium oxide: calcium hydroxide: WS280P = 7:4:4, the elongation at break is optimal, and the compression set is the best. In particular, when the mass ratio of magnesium oxide to calcium hydroxide in the composite auxiliary is greater, the compression set is obviously improved compared with example 5-1. The elongation at break of example 5-4 is obviously lower than the above groups, and the compression set is general, because the proportion of magnesium oxide is too large (mass ratio greater than 8), there is a residual reaction in the process, which will form a steric effect in the molecular chain, reduce the flexibility of the molecular chain, affect the elongation at break of the material, so that the elongation at break and compression set of the fluorine rubber are general. In example 5-5, the elongation at break is obviously lower than examples 5-2, 5-3 and 2, and the compression set is also general, because the proportion of WS280P is large (mass ratio greater than 7), the plasticizing effect is obviously greater than the bridging and "channel" effect, and the material becomes soft due to the plasticizing effect, which can be seen from the hardness that the hardness decreases, leading to the decrease of elongation at break and the obvious decrease of compression set.

[0086] Comparative example 6

[0087] The parameters and preparation steps of the comparative example group are consistent with example 2, example 5-1 to example 5-3, respectively, and the only difference is that the raw materials of the composite auxiliary are not pre-prepared in step S1, but are directly added with the reinforcing agent and the like in step S2.

[0088] The fluorine rubber prepared in comparative example 6 was detected for performance, and the specific detection results are shown in the table below:

[0089]

[0090]

[0091] From the above table, as the test results of Example 2, Example 5-1 to Example 5-3 and Comparative Example 6, Comparative Example 6-1, compared with Example 5-1, the elongation at break of the fluoroelastomer material is reduced, which is due to the fact that magnesium oxide, calcium hydroxide and WS 280P are not pretreated by compounding, but are directly added to the remaining raw materials of the rubber, and no active state of high active point is formed, and WS 280P cannot provide bridging and "channel" effect, so it has no improvement effect on the elongation at break. The elongation at break of the fluoroelastomer products of Comparative Examples 6-2 to 6-4 is greatly reduced, and the compression set performance is also poor, which is due to the fact that calcium hydroxide and WS 280P are directly added to the rubber raw materials without pre-treatment, and WS 280P is easy to adhere to the surface of calcium hydroxide, forming a film, reducing the activity of calcium hydroxide, resulting in low crosslinking density, and affecting the compression set performance.

[0092] Comparative Example 7

[0093] The parameters and preparation steps of the present comparative example are consistent with Example 2, the difference lies in that the type of fluorine raw rubber used is different, see the table below for details:

[0094] Type and amount of fluoroelastomer Example 2 Binary bisphenol vulcanization system fluoroelastomer - FE2601 : 100 parts Comparative Example 7-1 Binary bisphenol vulcanization system fluoroelastomer - FE2601 : 80 parts + ternary fluoroelastomer: 20 parts Comparative Example 7-2 Ternary fluoroelastomer: 100 parts, and no WS 280P was added in the complexing agent

[0095] The fluoroelastomer prepared in Comparative Example 7 was subjected to performance testing, and the specific test results are shown in the table below:

[0096]

[0097] From the above table, as the test results of Example 2 and Comparative Examples 7-1 and 7-2, the peel adhesion strength of Example 2 is higher than that of Comparative Example 7-1, which is due to the use of ternary rubber, resulting in a decrease in the adhesion performance of the rubber to the skeleton, while Comparative Example 7-2 uses ternary raw rubber, so the peel adhesion strength is naturally worse than Example 2. At the same time, from the results, Comparative Example 7-2 is slightly better than Comparative Example 7-1, which may be due to the use of ternary rubber, the intermolecular gap is smaller, and the adsorption force is greater than that of binary rubber and ternary rubber.

[0098] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by utilizing the content of the present application specification, or direct / indirect application in other related technical fields within the inventive concept of the present application are included in the patent protection scope of the present application.

Claims

1. A method for producing a fluoroelastomer having high elongation, characterized by, The high-elongation fluororubber is prepared from the following raw materials by weight: fluorine raw rubber 80-100 parts, vulcanizing agent 1.2-1.8 parts, reinforcing agent 20-25 parts, accelerator 0.3-0.6 parts, internal release agent 2.5-3.5 parts and composite auxiliary agent 10-20 parts; and the preparation method comprises the following steps: S1. The raw materials of the composite auxiliary agent are mixed in proportion, stirred uniformly, and then added into a mold for compression molding to obtain the composite auxiliary agent, wherein the composite auxiliary agent is compounded from magnesium oxide, calcium hydroxide and organosiloxane; S2. The fluorine raw rubber is first plasticized, then the reinforcing agent, the internal release agent and the composite auxiliary agent are added for further compounding, and after the discharge of the rubber, thin passing is performed, then the vulcanizing agent and the accelerator are added and mixed uniformly; S3. After the triangle bag is punched, thin passing is performed again, and the fluororubber with high elongation is obtained after sheeting.

2. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding the following components to a fluororubber base material and kneading them at a temperature of 150 to 200°C for 0.5 to 2 hours. The mass ratio of the magnesium oxide, the calcium hydroxide and the organosiloxane is 6-7:3-5:3-6.

3. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding the following components to a fluororubber base material and kneading them at 150 to 200°C for 1 to 3 hours. The fluorine raw rubber is a bisphenol vulcanization system fluorine raw rubber, the vulcanizing agent is bisphenol AF, and the accelerator is benzyl triphenyl phosphonium chloride.

4. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding the following components to a fluororubber base material and kneading them at 150 to 200°C for 1 to 3 hours. The reinforcing agent comprises at least one of calcium silicate or diatomite.

5. The method of claim 4, wherein the fluororubber having high elongation is prepared by adding the perfluoroalkyl ether compound to the fluororubber in the presence of the peroxide compound. The reinforcing agent is mixed from calcium silicate and diatomite at a mass ratio of 15:

10.

6. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding 0.1 to 10 parts by weight of the compound to 100 parts by weight of the fluororubber. The internal release agent is mixed from palm wax and high molecular alcohol ester compounds at a mass ratio of 5:

5.

7. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding 0.1 to 10 parts by weight of the compound of formula (1) to 100 parts by weight of a fluororubber base material. The raw materials of the fluororubber further comprise pigment auxiliary agent 2-4 parts.

8. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding 0.1 to 10 parts by weight of the compound to 100 parts by weight of the fluororubber. In step S1, the stirring temperature is 60-75℃, and the time is 6-7min.

9. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding 0.1 to 10 parts by weight of the compound of formula (1) to 100 parts by weight of a fluororubber base material. In step S2, the plasticizing temperature of the fluorine raw rubber is 80-90℃, and the time is 1-1.5min; and the compounding temperature is 90-110℃, and the time is 7-8min.

10. The method of claim 1, wherein the fluororubber having high elongation is prepared by adding 0.1 to 10 parts by weight of the compound of formula (1) to 100 parts by weight of a fluororubber base material. In step S2, the discharge temperature during the discharge of the rubber is 120-130℃.

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