High-insulation heat-resistant ethylene propylene diene monomer rubber material and preparation method thereof

Abstract

The invention discloses a high-insulation heat-resistant ethylene propylene diene monomer rubber material which is prepared from the following raw materials in parts by weight: 40-50 parts of low-Mooney-viscosity ethylene propylene diene monomer rubber, 40-60 parts of medium-Mooney-viscosity ethylene propylene diene monomer rubber, 10-30 parts of high-Mooney-viscosity ethylene propylene diene monomer rubber, 5-15 parts of zinc oxide, 1-3 parts of stearic acid, 1-2 parts of an anti-aging agent MB, 1-2 parts of an anti-aging agent RD, 1-2 parts of a flow promoter and 2-10 parts of tackifying resin, 25-55 parts of carbon black, 40-75 parts of an inorganic filler, 1-2 parts of a coupling agent, 5-20 parts of a plasticizer, 4-12 parts of a vulcanizing agent and 1-5 parts of a cross-linking auxiliary agent; the inorganic filler is a combination of white carbon black and Create-E2; and the cross-linking auxiliary agent is a combination of a cross-linking auxiliary agent TAIC-70PD and a cross-linking auxiliary agent HVA-2. The EPDM rubber material disclosed by the invention has the effects of long-time high temperature resistance and high insulation.

Description

TECHNICAL FIELD

[0001] The application relates to a high-insulation heat-resistant EPDM rubber material and a preparation method thereof. BACKGROUND

[0002] With the continuous development of the times, insulating materials have become indispensable key materials in the new energy automobile, power electronics and other industries. At present, EPDM rubber is generally used as a raw material to prepare insulating materials. EPDM rubber is the best heat-resistant material among general-purpose rubbers, can meet the working conditions of long-time high temperature of 150 DEG C, and has excellent insulation performance and a lower price than that of silicone rubber and chloroprene rubber. However, since EPDM rubber is a non-self-reinforced rubber, in order to obtain higher insulation performance, a large amount of inorganic filler such as white carbon black with excellent insulation is generally added. However, the white carbon black has a small particle size, a large specific surface area, a large number of polar hydroxyl groups and carboxyl groups, and certain compatibility problems with the non-polar EPDM rubber. Although the white carbon black has excellent insulation and certain reinforcing properties, if the amount of the white carbon black is too large, the rubber material will have problems such as uneven dispersion and agglomeration in the mixing process, thereby affecting the processing workability. SUMMARY

[0003] The application aims to provide a high-insulation heat-resistant EPDM rubber material and a preparation method thereof.

[0004] The application is achieved by the following technical scheme. The application relates to a high-insulation heat-resistant EPDM rubber material, which is prepared from the following raw materials in parts by weight: 40-50 parts of low-Mooney-Viscosity EPDM rubber, 40-60 parts of medium-Mooney-Viscosity EPDM rubber, 10-30 parts of high-Mooney-Viscosity EPDM rubber, 5-15 parts of zinc oxide, 1-3 parts of stearic acid, 1-2 parts of antioxidant MB, 1-2 parts of antioxidant RD, 1-2 parts of flow aid, 2-10 parts of tackifying resin, 25-55 parts of carbon black, 40-75 parts of inorganic filler, 1-2 parts of coupling agent, 5-20 parts of plasticizer, 4-12 parts of vulcanizing agent and 1-5 parts of crosslinking aid, wherein the total amount of the low-Mooney-Viscosity EPDM rubber, the medium-Mooney-Viscosity EPDM rubber and the high-Mooney-Viscosity EPDM rubber is 100 parts.

[0005] Preferably, the high-insulation heat-resistant EPDM rubber material is prepared from the following raw materials in parts by weight: 35 parts of low-Mooney-Viscosity EPDM rubber, 50 parts of medium-Mooney-Viscosity EPDM rubber, 15 parts of high-Mooney-Viscosity EPDM rubber, 5 parts of zinc oxide, 1-2 parts of stearic acid, 1 part of antioxidant MB, 1 part of antioxidant RD, 1-2 parts of flow aid, 2-10 parts of tackifying resin, 30-40 parts of carbon black, 65-75 parts of inorganic filler, 1-2 parts of coupling agent, 5-15 parts of plasticizer, 8 parts of vulcanizing agent and 1-5 parts of crosslinking aid.

[0006] More preferably, the high-insulation heat-resistant EPDM rubber material is made of raw materials including the following weight parts: 35 parts of low Mooney viscosity EPDM rubber, 50 parts of medium Mooney viscosity EPDM rubber, 15 parts of high Mooney viscosity EPDM rubber, 5 parts of zinc oxide, 1-2 parts of stearic acid, 1 part of antioxidant MB, 1 part of antioxidant RD, 1-2 parts of flow aid, 3-5 parts of tackifying resin, 30-40 parts of carbon black, 65-75 parts of inorganic filler, 2 parts of coupling agent, 10 parts of plasticizer, 8 parts of vulcanizing agent, and 3.5-4 parts of crosslinking aid.

[0007] More preferably, the high-insulation heat-resistant EPDM rubber material is made of raw materials including the following weight parts: 35 parts of low Mooney viscosity EPDM rubber, 50 parts of medium Mooney viscosity EPDM rubber, 15 parts of high Mooney viscosity EPDM rubber, 5 parts of zinc oxide, 1-2 parts of stearic acid, 1 part of antioxidant MB, 1 part of antioxidant RD, 1-2 parts of flow aid, 3-5 parts of tackifying resin, 30-40 parts of carbon black, 65-75 parts of inorganic filler, 2 parts of coupling agent, 10 parts of plasticizer, 8 parts of vulcanizing agent, and 3.5-4 parts of crosslinking aid.

[0008] The low Mooney viscosity EPDM rubber has a Mooney viscosity of 21-29 (ML (1＋4) 125℃), an ethylene content of 43.9%-48.1%, and an ENB content of 5.4%-6.6%.

[0009] Specifically, the low Mooney viscosity EPDM rubber can be EPDM Keltan 2650C.

[0010] The medium Mooney viscosity EPDM rubber has a Mooney viscosity of 39-51 (ML (1＋4) 100℃), an ethylene content of 44.2%-49.8%, and an ENB content of 4.2%-5.8%.

[0011] Specifically, the medium Mooney viscosity EPDM rubber can be EPDM EPT 4045M.

[0012] The high Mooney viscosity EPDM rubber has a Mooney viscosity of 59-67 (ML (1＋4) 125℃), an ethylene content of 61.9%-66.1%, and an ENB content of 4.3%-5.3%.

[0013] Specifically, the high Mooney viscosity EPDM rubber can be EPDM Keltan 6470C.

[0014] The carbon black is carbon black N550.

[0015] The weight ratio of the inorganic filler is (30-40):35, preferably the weight ratio of the white carbon black and Create-E2 is 35:35.

[0016] The white carbon black is a precipitated white carbon black.

[0017] The weight ratio of the carbon black and the white carbon black is 40:30-30:40, preferably 35:35.

[0018] The coupling agent is silane coupling agent A-172.

[0019] The plasticizer is plasticizer SUNPAR 2280.

[0020] The flow aid is STRUKTOL WB222.

[0021] The tackifying resin is resin 5100.

[0022] The vulcanizing agent is Perkadox BC-40B-PD.

[0023] The crosslinking aid is a combination of crosslinking aid TAIC-70PD and crosslinking aid HVA-2 in a weight ratio of (1-2):1.5, preferably a combination of crosslinking aid TAIC-70PD and crosslinking aid HVA-2 in a weight ratio of (1.5-2):1.5, and most preferably a combination of crosslinking aid TAIC-70PD and crosslinking aid HVA-2 in a weight ratio of 4:3.

[0024] A preparation method of the high-insulation heat-resistant EPDM rubber material, comprising the following steps: Step (1), cooling water is passed through the internal mixer, the temperature of the working chamber of the internal mixer is controlled to be 45-55 DEG C, the rotating speed of the rotor of the internal mixer is 32-35 rpm, low-Mooney viscosity EPDM rubber, medium-Mooney viscosity EPDM rubber and high-Mooney viscosity EPDM rubber are added, and mixing is carried out for 1-2 minutes, then zinc oxide, stearic acid, antioxidant MB, antioxidant RD, flow aid, tackifying resin are added, and mixing is carried out for 5-6 minutes. Step (2), the internal mixer continues to pass cooling water, carbon black, plasticizer, white carbon black, coupling agent and Create-E2 are added into the internal mixer for mixing, when the temperature of the internal mixer reaches 95 DEG C, crosslinking aid and vulcanizing agent are added, when the temperature of the internal mixer reaches 115-120 DEG C, the roll gap of the open mill is adjusted to be 0.1 mm, three triangular bags are punched, the roll gap is adjusted to be 0.5 mm, two rolls are punched, the roll gap of the open mill is adjusted to be 3.0 mm, and the sheet is discharged, thereby obtaining the EPDM rubber material.

[0025] The beneficial effects of the present application are as follows:

[0026] The ethylene propylene terpolymer can meet the working condition of long-time high temperature 150℃. Since the ethylene propylene terpolymer is a non-self-reinforced rubber, in order to obtain higher insulation performance, a large amount of inorganic filler needs to be added, but a large amount of inorganic filler will affect the processing process. The processing process of the rubber compound is very important, the present application selects low, medium and high Mooney viscosity raw rubber, mainly uses medium Mooney viscosity raw rubber, to balance the poor process caused by the addition of low and high Mooney viscosity raw rubber, to realize good processing process, and uses high Mooney viscosity raw rubber with ethylene content of about 70%, which can further improve the heat resistance of the rubber compound, and can further increase the amount of filling and reinforcing system (carbon black, white carbon black, Create-E2); select a specific proportion of crosslinking aid to ensure good vulcanization speed and crosslinking degree of the rubber compound, to realize good comprehensive physical and mechanical properties of the vulcanized rubber; by adding relatively high molecular weight high flash point paraffin oil, the heat resistance is not easy to migrate and separate out; the present application adopts a peroxide vulcanization system, wherein Perkadox BC-40B-PD is broken into two high-activity alkoxyl radicals under the action of heat, the alkoxyl radicals take tertiary hydrogen atoms from the rubber molecular chain to form carbon radicals, and the crosslinking aid contains multiple unsaturated double bonds, which can react with the rubber macromolecular radicals and polymerize to form a “bridging” structure under the action of the free radicals decomposed by the peroxide, greatly increasing the number of crosslinking points, and the crosslinking aid can inhibit the free radical transfer reaction of the active hydrogen atoms on the rubber molecular chain during peroxide vulcanization, form macromolecular radicals, and two adjacent rubber carbon radicals combine with each other to form a carbon-carbon single bond crosslinking bond between the rubber molecular chains, which has high bond energy and strong stability and is not easy to break, rearrange or degrade at high temperature.

[0027] The ethylene propylene terpolymer rubber compound product of the present application achieves the effects of long-time high temperature resistance and high insulation. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be further described below through specific embodiments.

[0029]

[0030] Note: Create-E2 (manufacturer: Ningbo Calitet New Material Co., Ltd.); precipitated white carbon black (manufacturer: Jiangsu Lianhe Chemical Co., Ltd., precipitated hydrated silicon dioxide, pH index 5.0-8.0, pH test value 6.8). EMBODIMENT

[0031] A high-insulation heat-resistant ethylene propylene terpolymer rubber compound, the raw materials and weight fractions of which are shown in Table 1, is prepared by the following method, the steps of which are as follows: Step (1), the internal mixer is cooled by cooling water, the temperature of the internal mixer working chamber is controlled at 55℃, the rotor speed of the internal mixer is 32 rpm, low Mooney viscosity EPDM rubber Keltan 2650C, medium Mooney viscosity EPDM rubber EPT4045M and high Mooney viscosity EPDM rubber Keltan 6470C are added, and the internal mixer is mixed for 1 minute, then zinc oxide, stearic acid, antioxidant MB, antioxidant RD, flow aid STRUKTOL WB222, tackifying resin 5100 are added, and the internal mixer is mixed for 6 minutes; Step (2), the internal mixer continues to be cooled by cooling water, carbon black N550, plasticizer SUNPAR 2280, precipitated silica, coupling agent A-172 and Create-E2 are added into the internal mixer for mixing, when the temperature of the internal mixer reaches 95℃, crosslinking aid TAIC-70PD, crosslinking aid HVA-2 and vulcanizing agent Perkadox BC-40B-PD are added, when the temperature of the internal mixer reaches 120℃, the roll gap of the open mill is adjusted to 0.1mm, three triangular bags are punched, the roll gap is adjusted to 0.5mm, two rolls are punched, the roll gap of the open mill is adjusted to 3.0mm, and the sheet is discharged, thereby obtaining the EPDM rubber compound. Example

[0032] On the basis of Example 1, the amount of crosslinking aid TAIC-70PD is adjusted to 2.0 parts, the specific formula is shown in Table 1, and the EPDM rubber compound is prepared according to the preparation method of Example 1. Example

[0033] On the basis of Example 1, the amount of crosslinking aid TAIC-70PD is adjusted to 2.5 parts, the specific formula is shown in Table 1, and the EPDM rubber compound is prepared according to the preparation method of Example 1. Example

[0034] On the basis of Example 2, the amounts of carbon black and white carbon black are adjusted, the specific formula is shown in Table 1, and the EPDM rubber compound is prepared according to the preparation method of Example 1. Example

[0035] On the basis of Example 2, the amounts of carbon black and white carbon black are continuously adjusted, the specific formula is shown in Table 1, and the EPDM rubber compound is prepared according to the preparation method of Example 1.

[0036] On the basis of Example 2, the amounts of carbon black and white carbon black are continuously adjusted, the specific formula is shown in Table 1, and the EPDM rubber compound is prepared according to the preparation method of Example 1.

[0037] On the basis of Example 2, the amounts of carbon black and white carbon black are continuously adjusted, the specific formula is shown in Table 1, and the EPDM rubber compound is prepared according to the preparation method of Example 1.

[0038] On the basis of Example 2, the raw materials were weighed according to Table 1, and the proportions of raw rubber and the amount of crosslinking coagent TAIC-70PD were adjusted, and the rubber compound was prepared according to the preparation method of Example 1.

[0039] The rubber compounds prepared in Examples 1-5 and Comparative Examples 1-3 were vulcanized, and the steps were as follows: Step (1), the vulcanization parameters of the flat vulcanization machine were set: temperature 170℃, pressure 15MPa, time 900s; Step (2), after the flat vulcanization machine reached the vulcanization temperature 170℃, the test piece and the pressure change block sample were put in; Step (3), after the vulcanization temperature was ensured to be 170℃, the mold was opened to take samples after the vulcanization time was reached, and the vulcanized rubber was obtained.

[0040] The properties of the rubber compound (vulcanized rubber) were detected, and are shown in Table 2.

[0041]

[0042] As can be seen from Table 2, the proportions of raw rubber used in Comparative Examples 1-3 are different, and the conventional hardness and tensile strength of the rubber compound using the ethylene-propylene-diene rubber Keltan 6470C are relatively good. With the increase of the amount of ethylene-propylene-diene rubber Keltan 6470C, the heat resistance and pressure change performance of the rubber compound will be better, but when Keltan 6470C reaches 25 parts, the rubber compound will have process problems such as non-molding, peeling, and uneven mixing, resulting in poor process performance and relatively reduced conventional elongation. The rubber compounds prepared in Examples 1-3 have increasing conventional hardness, increasing tensile strength first and then decreasing, and continuously decreasing elongation, which is related to the crosslinking degree of the rubber compound. When the amount of crosslinking coagent TAIC-70PD is 2.0 parts, the heat resistance of the rubber compound is the best. The amounts of carbon black and white carbon black used in Comparative Example 2, Example 4 and Example 5 are 40 parts and 30 parts, 35 parts and 35 parts, and 30 parts and 40 parts, respectively. The conventional hardness continuously increases, the tensile strength increases first and then decreases, and the elongation at break decreases slightly first and then obviously. It can be found by comparing Comparative Example 2 with Example 4 that with the increase of the amount of white carbon black, the volume resistivity of the rubber compound shows a trend of increasing, and the hardness change rate, strength change rate and elongation change rate of the heat resistance are all better. It can be found by comparing Example 4 with Example 5 that with the further increase of the amount of white carbon black, the volume resistivity of the rubber compound does not change, and the hardness change rate, strength change rate and elongation change rate of the heat resistance will be worse. In summary, the rubber compound prepared in Example 4 has the best conventional performance strength and pressure change performance, and the best heat resistance and insulation.

Claims

1. A high-insulation and heat-resistant EPDM rubber compound, characterized in that: It is made from the following raw materials in parts by weight: 40-50 parts low Mooney viscosity EPDM rubber, 40-60 parts medium Mooney viscosity EPDM rubber, 10-30 parts high Mooney viscosity EPDM rubber, 5-15 parts zinc oxide, 1-3 parts stearic acid, 1-2 parts antioxidant MB, 1-2 parts antioxidant RD, 1-2 parts flow aid, 2-10 parts tackifying resin, 25-55 parts carbon black, 40-75 parts inorganic filler, 1-2 parts chromium hydroxide, and 40-55 parts acetone. The crosslinking agent comprises 5-20 parts plasticizer, 4-12 parts vulcanizing agent, and 1-5 parts crosslinking aid; and the total amount of EPDM rubber with low Mooney viscosity, medium Mooney viscosity, and high Mooney viscosity is 100 parts; the inorganic filler is a combination of silica and Create-E2 in a weight ratio of (30-40):35; the crosslinking aid is a combination of crosslinking aid TAIC-70PD and crosslinking aid HVA-2 in a weight ratio of (1-2):1.

5.

2. The high-insulation and heat-resistant EPDM rubber compound according to claim 1, characterized in that: It is made from the following raw materials in parts by weight: 35 parts low Mooney viscosity EPDM rubber, 50 parts medium Mooney viscosity EPDM rubber, 15 parts high Mooney viscosity EPDM rubber, 5 parts zinc oxide, 1-2 parts stearic acid, 1 part antioxidant MB, 1 part antioxidant RD, 1-2 parts flow aid, 2-10 parts tackifying resin, 30-40 parts carbon black, 65-75 parts inorganic filler, 1-2 parts coupling agent, 5-15 parts plasticizer, 8 parts vulcanizing agent, and 1-5 parts crosslinking aid.

3. The high-insulation and heat-resistant EPDM rubber compound according to claim 2, characterized in that: It is made from the following raw materials in parts by weight: 35 parts low Mooney viscosity EPDM rubber, 50 parts medium Mooney viscosity EPDM rubber, 15 parts high Mooney viscosity EPDM rubber, 5 parts zinc oxide, 1-2 parts stearic acid, 1 part antioxidant MB, 1 part antioxidant RD, 1-2 parts flow aid, 3-5 parts tackifying resin, 30-40 parts carbon black, 65-75 parts inorganic filler, 2 parts coupling agent, 10 parts plasticizer, 8 parts vulcanizing agent, and 3.5-4 parts crosslinking aid.

4. The high-insulation and heat-resistant EPDM rubber compound according to claim 3, characterized in that: It is made from the following raw materials in parts by weight: 35 parts low Mooney viscosity EPDM rubber, 50 parts medium Mooney viscosity EPDM rubber, 15 parts high Mooney viscosity EPDM rubber, 5 parts zinc oxide, 1 part stearic acid, 1 part antioxidant MB, 1 part antioxidant RD, 2 parts flow aid, 4 parts tackifying resin, 35 parts carbon black, 70 parts inorganic filler, 2 parts coupling agent, 10 parts plasticizer, 8 parts vulcanizing agent, and 3.5 parts crosslinking aid.

5. The high-insulation and heat-resistant EPDM rubber compound according to any one of claims 1-4, characterized in that: The Mooney viscosity of the low Mooney viscosity EPDM rubber is 21-29 (mL). (1＋4) The ethylene content is 43.9%–48.1%, and the ENB content is 5.4%–6.6% (at 125℃); the Mooney viscosity of the medium Mooney viscosity EPDM rubber is 39–51 (mL). (1＋4) (100℃), ethylene content is 44.2-49.8%, ENB content is 4.2-5.8%; the Mooney viscosity of the high Mooney viscosity EPDM rubber is 59-67 (ML). (1＋4) (125℃), ethylene content is 61.9-66.1%, ENB content is 4.3-5.3%.

6. The high-insulation and heat-resistant EPDM rubber compound according to claim 5, characterized in that: The low Mooney viscosity EPDM rubber is selected from EPDM rubber Keltan 2650C; the medium Mooney viscosity EPDM rubber is selected from EPDM rubber EPT 4045M; and the high Mooney viscosity EPDM rubber is selected from EPDM rubber Keltan 6470C.

7. The high-insulation and heat-resistant EPDM rubber compound according to any one of claims 1-4, characterized in that: The carbon black is carbon black N550; the silica is precipitated silica; the coupling agent is silane coupling agent A-172; the plasticizer is plasticizer SUNPAR 2280; the flow aid is STRUKTOL WB222; the tackifying resin is resin 5100; and the vulcanizing agent is Perkadox BC-40B-PD.

8. The high-insulation and heat-resistant EPDM rubber compound according to any one of claims 1-4, characterized in that: The inorganic filler is a combination of silica and Create-E2 in a weight ratio of 35:35; the weight ratio of carbon black to silica is 40:30 to 30:40, preferably 35:

35.

9. The high-insulation and heat-resistant EPDM rubber compound according to any one of claims 1-4, characterized in that: The crosslinking aid is a combination of crosslinking aid TAIC-70PD and crosslinking aid HVA-2 in a weight ratio of (1.5~2):1.5, preferably a combination of crosslinking aid TAIC-70PD and crosslinking aid HVA-2 in a weight ratio of 4:

3.

10. A method for preparing a high-insulation, heat-resistant EPDM rubber compound as described in claim 1, characterized in that: Includes the following steps: Step (1): Cool water is introduced into the internal mixer to control the temperature of the internal mixer chamber to be 45-55℃ and the rotor speed to be 32-35rpm. Low Mooney viscosity EPDM rubber, medium Mooney viscosity EPDM rubber and high Mooney viscosity EPDM rubber are added and internally mixed for 1-2 minutes. Then zinc oxide, stearic acid, antioxidant MB, antioxidant RD, flow aid and tackifying resin are added and mixed for 5-6 minutes. Step (2): Continue to circulate cooling water through the internal mixer, add carbon black, plasticizer, silica, coupling agent and Create-E2 into the internal mixer and mix. When the internal mixer temperature reaches 95℃, add crosslinking aid and vulcanizing agent. When the internal mixer temperature reaches 115~120℃, discharge the rubber: adjust the roller gap of the open mill to 0.1mm, make 3 triangular wraps, adjust the roller gap to 0.5mm, make 2 rolls, adjust the roller gap of the open mill to 3.0mm, and extrude the sheet to obtain EPDM rubber compound.

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