CN104194109A - Thermo-oxidative ageing resistant epoxidized natural rubber composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a hydrotalcite/epoxidized natural rubber composite material and a preparation method thereof. Firstly, the hydrotalcite is modified, then dispersed with deionized water, epoxidized natural latex is added, and ultrasonic stirring is continued to obtain latex state Hydrotalcite/epoxidized natural rubber composite material; through adding vulcanization processing aids, obtain aging-resistant epoxidized natural rubber composite material; the heat-resistant oxygen aging epoxidized natural rubber composite material with excellent performance prepared by the present invention can be used Used in high-performance tires, medical latex products, rubber hoses, shoe soles and other epoxidized natural rubber products.

Description

A kind of heat-resistant oxygen aging epoxidized natural rubber composite material and preparation method thereof

【Technical field】

The invention relates to an epoxidized natural rubber composite material and a preparation method thereof, in particular to a heat-resistant oxygen aging epoxidized natural rubber composite material and a preparation method thereof.

【Background technique】

Epoxidized natural rubber is obtained by epoxidizing natural rubber. It is usually prepared by adding formic acid or acetic acid and hydrogen peroxide to natural latex under acidic conditions. Since epoxidized natural rubber introduces epoxy groups into natural rubber molecules, it leads to the increase of the polarity of the rubber molecules and the increase of the force between the rubber molecules, which makes it have some special properties, such as excellent airtight resistance properties, oil resistance, good wet skid resistance and low rolling resistance, and good adhesion. Therefore, epoxidized natural rubber is widely used, especially in the application of green tires, because epoxidized natural rubber has low rolling resistance and high wet skid resistance, it has broad application prospects in the manufacture of high-performance green tires . However, epoxidized natural rubber products are prone to rubber aging due to the influence of environmental factors during processing or use. Therefore, epoxidized natural rubber products generally have problems such as short storage time, short service life, and aging stickiness. The application of epoxidized natural rubber is limited to a great extent.

Therefore, also provide a kind of epoxidized natural rubber composite material and preparation method thereof with good mechanical properties and anti-aging performance, can be used for medical latex products, tires, epoxidized natural rubber products such as hoses, soles, etc. Widen the application of epoxidized natural rubber to a great extent.

【Content of invention】

The object of the present invention is to provide a heat-resistant oxygen aging epoxidized natural rubber composite material and a preparation method thereof.

Specifically, the present invention provides a hydrotalcite/epoxidized natural rubber composite material; its preparation method is to first modify the hydrotalcite, then disperse it with deionized water, add epoxidized natural rubber latex, and continue to ultrasonically The hydrotalcite/epoxidized natural rubber composite material in the latex state is obtained by stirring; the aging-resistant epoxidized natural rubber composite material is obtained by adding vulcanization processing aids.

A kind of heat-resistant oxygen aging epoxidized natural rubber composite material of the present invention is characterized in that it comprises the following components by weight:

Epoxidized natural rubber latex by dry glue 100 parts;

Hydrotalcite 3-30 parts.

In order to prepare the heat-resistant oxygen aging epoxidized natural rubber composite material of the present invention, one of silane coupling agent or sodium stearate of 5% to 10% of the hydrotalcite consumption can also be selected;

In order to prepare the heat-resistant oxygen aging epoxidized natural rubber composite material of the present invention, the compounding agent of following formula can also be added:

raw material name Epoxidized Natural Rubber sulfur Accelerator NS Zinc oxide stearic acid parts by weight 100 1.5 1.5 5 2

The parts by weight in the present invention may be known content units such as gram or kilogram.

The epoxidized natural rubber of the present invention is 5-50% epoxidized natural latex prepared by natural latex through epoxidation reaction;

In the hydrotalcite of the present invention, the layer cation is Mg ²⁺ or Al ³⁺ , the interlayer anion is CO ₃ 2- , OH ^- , SO ₄ ^2- , NO ₃ ^- or Cl ^- , and the average particle size is 0.5 -1.2 μm, the amount ratio of epoxidized natural latex with an epoxidation degree of 5-50% in 100 parts of dry rubber is 3 to 30 parts;

The silane coupling agent of the present invention can be selected from one of Si-69 or KH550 or KH560, and its consumption is 5-10% of the hydrotalcite consumption;

The hydrotalcite/epoxidized natural rubber composite material prepared by the present invention can adopt sulfur vulcanization system (ordinary vulcanization system, semi-effective vulcanization system, effective vulcanization system) and peroxide vulcanization system to make prevulcanized latex, and produce each It can also be mixed and vulcanized by conventional processing technology to make various dry rubber products.

A kind of preparation method of heat-resistant oxygen aging epoxidized natural rubber composite material of the present invention is as follows:

Weigh a certain amount of hydrotalcite, add a certain amount of deionized water, and in the state of ultrasonic dispersion while stirring, add a certain amount of silane coupling agent or sodium stearate, and place it in a water bath at 30-40°C for continuous Stir for 24 hours, then add epoxidized natural latex, continue ultrasonic stirring for 0.5 to 1 hour to obtain latex-state hydrotalcite/epoxidized natural rubber composite material; Carry out coagulation, tabletting, granulation, and dry to obtain the hydrotalcite/epoxidized natural rubber composite material in the state of dry glue; add various compounding agents to the composite material according to the formula for mixing, and obtain the heat-resistant oxygen aging epoxidized natural rubber composite material. Rubber compound.

【Key points of the present invention】

Key point of the present invention is:

The hydrotalcite used in the present invention, also known as layered double hydroxides (LDHs for short), is a typical anionic layered compound, and its typical molecular composition is Mg ₆ Al ₂ (OH) ₁₆ CO ₃ ·4H ₂ O. Because the surface of hydrotalcite has strong alkalinity and good hydrophilicity, by adding modified hydrotalcite to epoxidized natural rubber latex, a large amount of non-bridging hydroxyl groups existing on the surface of hydrotalcite and epoxidized natural rubber The reaction of the epoxy group makes the hydrotalcite better bond and disperse in the rubber particle system, and it can also absorb and neutralize the free acid produced in the aging process of epoxidized natural rubber, and inhibit the progress of the aging process , thereby improving the aging resistance of epoxidized natural rubber composites.

[Beneficial effects of the present invention]

The heat-resistant oxygen aging epoxidized natural rubber composite material prepared by the present invention has the following remarkable effects:

——The tensile strength is 25.2MPa～32.8MPa;

——300% modulus stress is 2.05MPa～2.74MPa;

——The tear strength is 31MPa～43MPa;

——After aging in hot air at 100℃×24h, the tensile strength retention rate of the composite material is 69%-93%, and the elongation retention rate at break is 80%-96%;

---Because hydrotalcite has a significant inhibitory effect on the growth of various microorganisms and fungi, it has the characteristics of highly dispersed effective bactericidal components and high bactericidal efficiency; the composite material has low heat generation, good wet skid resistance, thermal oxygen and heat Good stability and other characteristics. Therefore, the epoxidized natural rubber composite material prepared by the present invention has great application prospects in high-performance tires, medical gloves, rubber hoses, etc.;

---The hydrotalcite used in the present invention is non-toxic, non-polluting, and the preparation method is simple; the cost is low;

---The technical process provided by the present invention is simple and easy for large-scale production.

【Detailed ways】

Parts used hereinafter are by weight unless otherwise stated.

The test of tensile strength, elongation at break and modulus stress is carried out according to GB/T528-2009; the tear strength test is carried out according to GB/T529-2008. Heat air aging resistance: Hang the sample at a certain distance in a hot air aging test box with an experimental temperature of 100°C for 24 hours, then take out the sample, and measure its tensile strength and elongation at break. Performance retention = measured value of performance after aging of the sample/measured value before experimental aging × 100%.

Example 1

Firstly, the 3 layers of laminate cations are Mg ²⁺ or Al ³⁺ , interlayer anions are CO ₃ 2- , OH ^- , SO ₄ ^2- , NO ₃ ^- or Cl ^- , and the average particle size is 0.5-1.2 μm of water Add talc to 20ml of deionized water, and in the state of ultrasonic dispersion while stirring, add 5% (weight) Si-69 of hydrotalcite, place it in a water bath at 30°C and continuously stir for 24h, then add 100 parts of dry gel meter The epoxidized natural rubber latex of the epoxidation degree 5%, continues ultrasonic stirring 0.6h, obtains the hydrotalcite/epoxidized natural rubber composite material of latex state; The composite material is solidified, pressed into tablets, granulated, and dried to obtain a hydrotalcite/epoxidized natural rubber composite material in a dry state. Add various compounding ingredients to the composite material according to the formula shown in Table 1 and mix to obtain the mixed rubber. After the mixed rubber is parked at room temperature for 3 to 6 hours, it is vulcanized on a flat vulcanizing machine at 150°C and 15MPa. The vulcanization time _T90 is measured by a vulcanization meter (MDR 2000). The vulcanized film was parked at room temperature for 20h, and then the physical and mechanical properties of the vulcanized rubber were measured.

Table 1 The basic formula of the experiment

raw material name Epoxidized Natural Rubber sulfur Accelerator NS Zinc oxide stearic acid parts by weight 100 1.5 1.5 5 2

Table 2 Mechanical properties of epoxidized natural rubber vulcanizates with epoxidation degree of 5%

project Tensile strength/MPa Elongation at break/% 300% modulus stress/MPa Tear strength/MPa No added hydrotalcite 18.01 720 1.53 22.86 Add hydrotalcite 25.21 662 1.97 31.21

Table 3 Retention of tensile strength and elongation at break of hydrotalcite/epoxidized natural rubber composites

project Tensile strength retention/% Tensile elongation retention/% No added hydrotalcite 65.14 71.23 Add hydrotalcite 76.23 85.36

The mechanical properties of hydrotalcite/epoxidized natural rubber composites are shown in Table 2. It can be seen from Table 2 that the tensile strength of the hydrotalcite/epoxidized natural rubber composite is 25.21Mpa, which is 7.2Mpa greater than that of the vulcanized rubber without adding hydrotalcite; the 300% modulus stress is increased from 1.53MPa to 1.97Mpa; The tear strength increased from 22.86MPa to 31.21Mpa.

Table 3 shows the tensile strength retention and elongation retention of hydrotalcite/epoxidized natural rubber composites after hot air aging. It can be seen from Table 3 that the anti-aging properties of hydrotalcite/epoxidized natural rubber composites are significantly improved. For example, after aging at 100 °C for 24 hours, the tensile strength and The retention rates of elongation at break were 76.23% and 85.36%, respectively.

Example 2

First, make 10 parts of water with laminate cations as Mg ²⁺ or Al ³⁺ , interlayer anions as CO ₃ ^2- , OH ^- , SO ₄ ^2- , NO ₃ ^- or Cl ^- with an average particle size of 0.5-1.2 μm Add talc to 30ml of deionized water, and in the state of ultrasonic dispersion while stirring, add 7% (weight) sodium stearate of hydrotalcite, place it in a water bath at 35°C and stir continuously for 24h, then add 100 parts of dry glue The epoxidized natural rubber latex with the epoxidized degree of 20% is continued to be ultrasonically stirred for 0.6h to obtain the hydrotalcite/epoxidized natural rubber composite material in the latex state; the hydrotalcite/epoxidized natural rubber in the latex state is The rubber composite material is solidified, pressed into tablets, granulated, and dried to obtain a hydrotalcite/epoxidized natural rubber composite material in a dry state. The composite material is mixed according to the formula shown in Table 1 by adding various compounding agents to obtain a mixed rubber. After the mixed rubber is parked at room temperature for 3 to 6 hours, it is vulcanized on a flat vulcanizer at 150 ° C and 15 MPa. The vulcanization time _T90 is measured by a vulcanization meter (MDR 2000). The vulcanized film was parked at room temperature for 20h, and then the physical and mechanical properties of the vulcanized rubber were measured.

Table 4 Mechanical properties of epoxidized natural rubber vulcanizates with epoxidation degree of 20%

project Tensile strength/MPa Elongation at break/% 300% modulus stress/MPa Tear strength/MPa No added hydrotalcite 21.52 670 1.61 23.49 Add hydrotalcite 28.54 623 2.14 32.13

Table 5 Retention of tensile strength and elongation at break of hydrotalcite/epoxidized natural rubber composites

project Tensile strength retention/% Tensile elongation retention/% No added hydrotalcite 61.14 70.56 Add hydrotalcite 80.23 90.21

The mechanical properties of hydrotalcite/epoxidized natural rubber composites are shown in Table 4. It can be seen from Table 4 that the tensile strength of the hydrotalcite/epoxidized natural rubber composite is 28.54Mpa, which is 7.02Mpa greater than that of the vulcanized rubber without adding hydrotalcite; the 300% modulus stress is increased from 1.61MPa to 2.14Mpa; The tear strength increased from 23.49MPa to 32.13Mpa.

Table 5 shows the tensile strength retention and elongation retention of hydrotalcite/epoxidized natural rubber composites after hot air aging. It can be seen from Table 5 that the anti-aging properties of hydrotalcite/epoxidized natural rubber composites are significantly improved. For example, after aging at 100 °C for 24 hours, the tensile strength and The retention rates of elongation at break were 80.23% and 90.21%, respectively.

Example 3

First, make 20 parts of water with laminate cations as Mg ²⁺ or Al ³⁺ , interlayer anions as CO ₃ ^2- , OH ^- , SO ₄ ^2- , NO ₃ ^- or Cl ^- with an average particle size of 0.5-1.2 μm Add talc to 40ml of deionized water, and in the state of ultrasonic dispersion while stirring, add 7% (weight) of KH 550 of hydrotalcite, place it in a water bath at 40°C and continuously stir for 24h, then add 100 parts of ring dry gel meter The epoxidized natural rubber latex with an oxidation degree of 40% is continuously ultrasonically stirred for 1h to obtain the hydrotalcite/epoxidized natural rubber composite material in the latex state; Solidification, tableting, granulation, and drying to obtain a hydrotalcite/epoxidized natural rubber composite material in a dry state. Add various compounding ingredients to the composite material according to the formula shown in Table 1 and mix to obtain the mixed rubber. After the mixed rubber is parked at room temperature for 3 to 6 hours, it is vulcanized on a flat vulcanizing machine at 150°C and 15MPa. The vulcanization time _T90 is measured by a vulcanization meter (MDR 2000). The vulcanized film was parked at room temperature for 20h, and then the physical and mechanical properties of the vulcanized rubber were measured.

Table 6 Mechanical properties of epoxidized natural rubber vulcanizate with epoxidation degree of 40%

project Tensile strength/MPa Elongation at break/% 300% modulus stress/MPa Tear strength/MPa No added hydrotalcite 23.16 643 1.73 22.54 Add hydrotalcite 31.74 616 2.21 35.81

Table 7 Tensile strength retention and elongation retention of hydrotalcite/epoxidized natural rubber composites

project Tensile strength retention/% Tensile elongation retention/% No added hydrotalcite 57.32 79.95 Add hydrotalcite 86.87 91.23

The mechanical properties of hydrotalcite/epoxidized natural rubber composites are shown in Table 7. It can be seen from Table 7 that the tensile strength of the hydrotalcite/epoxidized natural rubber composite is 31.74Mpa, which is 8.58Mpa greater than that of the vulcanized rubber without adding hydrotalcite; the 300% modulus stress is increased from 1.73MPa to 2.21Mpa; The tear strength increased from 22.54MPa to 35.81Mpa.

Table 8 shows the tensile strength retention and elongation retention of hydrotalcite/epoxidized natural rubber composites after hot air aging. It can be seen from Table 8 that the aging resistance of hydrotalcite/epoxidized natural rubber composites is significantly improved. For example, after aging at 100°C for 24 hours, the tensile strength and tensile The elongation retention rates were 86.87% and 91.23%, respectively.

Example 4

First, make 30 parts of water with laminate cations as Mg ²⁺ or Al ³⁺ , interlayer anions as CO ₃ ^2- , OH ^- , SO ₄ ^2- , NO ₃ ^- or Cl ^- with an average particle size of 0.5-1.2 μm Add talc to 50ml of deionized water, and in the state of ultrasonic dispersion while stirring, add 10% (weight) of KH 560 of hydrotalcite, place it in a water bath at 40°C and continuously stir for 24h, then add 100 parts of ring dry gel meter The epoxidized natural rubber latex with an oxidation degree of 50% is continued to be stirred ultrasonically for 1 hour to obtain the hydrotalcite/epoxidized natural rubber composite material in the latex state; Solidification, tableting, granulation, and drying to obtain a hydrotalcite/epoxidized natural rubber composite material in a dry state. Add various compounding ingredients to the composite material according to the formula shown in Table 1 and mix to obtain the mixed rubber. After the mixed rubber is parked at room temperature for 3 to 6 hours, it is vulcanized on a flat vulcanizing machine at 150°C and 15MPa. The vulcanization time _T90 is measured by a vulcanization meter (MDR 2000). The vulcanized film was parked at room temperature for 20h, and then the physical and mechanical properties of the vulcanized rubber were measured.

Table 9 Mechanical properties of epoxidized natural rubber vulcanizates with epoxidation degree of 50%

project Tensile strength/MPa Elongation at break/% 300% modulus stress/MPa Tear strength/MPa No added hydrotalcite 24.35 632 1.78 23.87 Add hydrotalcite 31.67 605 2.32 37.12

Table 10 Tensile strength retention and elongation retention of hydrotalcite/epoxidized natural rubber composites

project Tensile strength retention/% Tensile elongation retention/% No added hydrotalcite 58.44 81.86 Add hydrotalcite 89.87 94.32

The mechanical properties of hydrotalcite/epoxidized natural rubber composites are shown in Table 9. It can be seen from Table 9 that the tensile strength of the hydrotalcite/epoxidized natural rubber composite is 31.67Mpa, which is 7.32Mpa greater than that of the vulcanized rubber without adding hydrotalcite; the 300% modulus stress is increased from 1.78MPa to 2.32Mpa; The tear strength increased from 23.87MPa to 37.12Mpa.

Table 10 shows the tensile strength retention and elongation retention of hydrotalcite/epoxidized natural rubber composites after hot air aging. It can be seen from Table 10 that the anti-aging performance of hydrotalcite/epoxidized natural rubber composites is significantly improved. The elongation retention rates were 89.87% and 94.32%, respectively.

Claims (3)

1. A heat-resistant oxygen aging epoxidized natural rubber composite material is characterized in that it comprises the following components by weight: Epoxidized natural rubber latex by dry glue 100 parts; Hydrotalcite 3-30 parts; The epoxidized natural rubber latex is 5-50% epoxidized natural rubber latex prepared by natural latex through epoxidation reaction; the hydrotalcite, its laminate cation is Mg ²⁺ or Al ³⁺ , the interlayer anion is CO ₃ ^2- , OH ^- , SO ₄ ^2- , NO ₃ ^- or Cl ^- , and the average particle size is 0.5-1.2 μm. 2. a kind of heat-resistant oxygen aging epoxidized natural rubber composite material according to claim 1, is characterized in that also can select to add 5～10% silane coupling agent or sodium stearate of hydrotalcite consumption during preparation One of: and the compounding agent of the following formula can also be added: raw material name Epoxidized Natural Rubber sulfur Accelerator NS Zinc oxide stearic acid parts by weight 100 1.5 1.5 5 2 The silane coupling agent is one of Si-69 or KH550 or KH560. 3. according to the preparation method of a kind of heat-resistant oxygen aging epoxidized natural rubber composite material described in claim 1 or 2, it is characterized in that comprising as follows: Weigh a certain amount of hydrotalcite, add a certain amount of deionized water, and in the state of ultrasonic dispersion while stirring, add a certain amount of silane coupling agent or sodium stearate, and place it in a water bath at 30-40°C for continuous Stir for 24 hours, then add epoxidized natural rubber latex, continue to ultrasonically stir for 0.5 to 1 hour to obtain latex-state hydrotalcite/epoxidized natural rubber composite material; Carry out coagulation, tabletting, granulation, and dry to obtain the hydrotalcite/epoxidized natural rubber composite material in the state of dry glue; add various compounding agents to the composite material according to the formula and mix to obtain the heat-resistant oxygen aging epoxidized natural rubber composite material. Rubber compound.