WO2018095221A1 - Magnetic rubber reinforced by means of unsaturated carboxylate and preparation method therefor - Google Patents

Abstract

Disclosed are a magnetic rubber reinforced by means of unsaturated carboxylate and a preparation method therefor. The magnetic rubber consists of the following raw materials in parts by mass: 100 parts rubber, 70-100 parts micron-sized ferriferous oxide powder, 5-15 parts unsaturated carboxylate, 0.5-2.5 parts vulcanizing agent and 0.83-4.16 parts vulcanization accelerator; the unsaturated carboxylate is one or more from among zinc methacrylate, magnesium methacrylate, zinc acrylate and magnesium acrylate; the vulcanizing agent is an alkyl peroxide; the resulting magnetic rubber has a tensile strength of more than 6.83 MPa, a tear strength of more than 13.98 MPa, and a saturation magnetic induction intensity of more than 29.03 emu/g.

Description

Magnetic rubber reinforced by unsaturated carboxylate and preparation method thereof Technical field

The invention relates to a magnetic rubber, in particular to a soft magnetic magnetic rubber which is reinforced by an unsaturated carboxylate and has excellent mechanical properties and a preparation method thereof, and belongs to the technical field of functional polymer composite materials.

Background technique

At present, soft magnetic materials are widely used and popularized in the fields of electronic communication products and automotive parts, and are developing in the direction of high frequency, low loss, high temperature resistance, strong anti-interference and light weight. The general ferromagnetic steel magnetic materials are limited in use in special occasions where the miniaturization and the shape of the molding are complicated due to the disadvantages of high density, hardness, and difficulty in processing and molding. With the increasing miniaturization, diversification and complexity of electronic and electrical equipment and some of its automotive parts. It is difficult to make a micro-miniature, complex-shaped part of a general ferromagnetic steel, and it is easy to be broken even if it is used.

Magnetic rubber—refers to a rubber material that has magnetic properties that can be utilized. It is generally a flexible magnetic material that has been finely prepared from magnetic powder, rubber, and compounding agent. The magnetic properties depend mainly on the type and amount of magnetic powder selected. Preparation process, etc. The powdered magnetic material is incorporated into an elastomeric polymer material such as rubber, and the resulting magnetic material is less likely to be broken. Magnetic rubber is soft and flexible, has good processing properties, and has various molecular structure changes. It has the characteristics that ferromagnetic steel cannot replace. The application research of magnetic rubber has become one of the hotspots in the research field of functional polymer materials. Generally, in order to obtain high saturation magnetic flux density, saturation magnetization, and low coercive force, it is necessary to increase the filling amount of the magnetic powder in the rubber; however, as the filling amount of the magnetic powder increases, the mechanical properties of the magnetic rubber tend to be remarkable. The decrease is due in part to the poor compatibility of the magnetic powder to the rubber matrix, and on the other hand because the magnetic powder tends to agglomerate in the rubber matrix, which leads to limitations in practical applications. Although there are related literature reports at home and abroad: pretreatment of magnetic powder or modification of magnetic powder by chemical additives such as silane coupling agent and titanate coupling agent, thereby improving the compatibility of magnetic powder with polymer matrix and magnetic powder The dispersibility in the polymer matrix further increases the mechanical properties of the magnetic polymer. However, the pretreatment process is complicated, the cycle is long, the cost is high, and the improvement effect on the high-filled magnetic polymeric material is not obvious, which makes it difficult to promote in practical applications.

Chinese invention patent application (CN102875854A) reports on a method for preparing high-strength magnetic rubber by using 110 phr of polymer (including natural rubber, neoprene, carboxylated nitrile rubber, PVC resin, phenolic resin, polyvinyl methyl ether, Polyethylene), 100 phr hard magnetic magnetic powder, 6 phr coupling agent, 16 phr sulfur vulcanizing agent and accelerator are first mixed uniformly; then added to the rubber mixing machine, rubberized at 170-180 ° C, and ground into a paste; Then, it is poured into a mold, cooled and solidified; finally, the cured sample is magnetized to obtain a product. However, due to the silane coupling agent KH-570 in the formulation It can not effectively improve the compatibility between the magnetic powder and the rubber matrix and disperse the magnetic powder in the rubber matrix. Therefore, the tensile strength of the obtained rubber material is only 5.7 MPa, which cannot meet the requirements for some occasions with high strength requirements. .

Summary of the invention

The object of the present invention is to overcome the problems existing in the prior art, to provide a magnetic rubber reinforced by an unsaturated carboxylate and a preparation method thereof, and the obtained magnetic rubber has a tensile strength of 6.83 MPa or more and a tear strength of 13.98. Above MPa, the saturation magnetic induction intensity is 29.03 emu/g or more.

The unsaturated carboxylate of the present invention is one or more of zinc methacrylate, magnesium methacrylate, zinc acrylate and magnesium acrylate. At present, in the rubber field, since these unsaturated carboxylate structures contain double bonds, free radicals can be generated under the action of an initiator, thereby causing cross-linking and grafting reaction of rubber macromolecules, and the crosslinking of rubber is remarkably improved. Efficiency, crosslink density, and structural composition of the crosslinks are changed. Therefore, the unsaturated carboxylic acid salt of the prior art is usually used as a co-crosslinking agent for a peroxide vulcanizing agent, and it is usually used in an amount of from 1 to 3 phr (the amount of the rubber is 100 phr).

In the present invention, the unsaturated carboxylate is used as a reinforcing agent, a reaction compatibilizer and a co-crosslinking agent in an amount of 5 to 20 phr (the amount of the rubber is 100 phr). The mechanism of action is: under the action of peroxide, the unsaturated carboxylate will undergo grafting and self-polymerization in the rubber matrix to form an ionic cross-linking bond, which will enhance the rubber and pull the rubber compound. The tensile strength and hardness are improved to some extent. At the same time, through the interaction between the metal ion clusters in the unsaturated carboxylate, the carbonyl group and the ferroferric oxide magnetic powder, the compatibility of the magnetic powder with the rubber matrix is improved, the dispersion of the magnetic powder in the rubber matrix is improved, and The mechanical properties of the magnetic rubber are significantly improved without affecting the magnetic properties of the ferroferric oxide particles.

After the vulcanizate prepared by the invention is vulcanized and molded, the magnetization curve and the hysteresis loop of the product are measured by vibrating the sample magnetometer, and the magnetic rubber mechanics obtained by the unsaturated carboxylate reinforcement is found. The performance enhancement is very remarkable, the tensile strength can reach 6.83 MPa or more, and the comparative ratio (without adding unsaturated carboxylate) is increased by 2 to 6 times, and the tear strength is also greatly improved to 13.98 MPa or more. . The magnetic properties of the product of the invention are obviously improved while the mechanical properties are obviously improved, so that the magnetic rubber prepared by the invention can be applied to special occasions with high requirements on mechanical properties, and can make up for the lack of mechanical properties of some magnetic rubbers. Disadvantages. The invention better solves how to significantly improve the mechanical properties of the magnetic rubber while maintaining the magnetic properties of the magnetic rubber.

The above technical object of the present invention is achieved by the following technical solutions:

A magnetic rubber reinforced by an unsaturated carboxylic acid salt, the raw material composition of which is in parts by mass:

Rubber: 100 parts;

Micron-sized ferroferric oxide powder: 70-100 parts;

Unsaturated carboxylate: 5 to 15 parts;

Vulcanizing agent: 0.5 to 2.5 parts;

Vulcanization accelerator: 0.83 to 4.16 parts;

The unsaturated carboxylate is one or more of zinc methacrylate, magnesium methacrylate, zinc acrylate and magnesium acrylate;

The vulcanizing agent is an alkyl peroxide;

The micron-sized ferroferric oxide magnetic powder has a particle diameter of 0.1 to 5 um.

The vulcanization accelerator is one or more of triallyl cyanurate, triallyl isocyanurate and 1,2-polybutadiene;

During preparation, at room temperature, the rubber is first masticized on the open mill, the unsaturated carboxylate is added, and the rubber is tapped, rolled, and triangled until the mixture is evenly mixed; then the ferroferric oxide powder is added to perform tapping. Winding, triangle; adding vulcanizing agent and vulcanization accelerator until the mixing is uniform, and the film is cooled and cooled to obtain a rubber compound; then the rubber is vulcanized and molded; finally, magnetization is performed to obtain a magnetic rubber.

For the purpose of further achieving the present invention, preferably, the alkyl peroxide is dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1 One or more of 3-bis(tert-butylperoxy)hexane, benzoyl peroxide and 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane Kind. The alkyl peroxide of the invention promotes the vulcanization of the rubber to form a crosslinked network under high temperature conditions, and also causes the unsaturated carboxylate to be grafted into the rubber macromolecular chain to form an ion crosslink bond, which makes the mechanical properties of the rubber Significantly enhanced; and the interaction between the metal ion clusters on the unsaturated carboxylate, the carbonyl group and the ferroferric oxide improves the phase of the ferroferric oxide magnetic powder and the rubber matrix without destroying the magnetic properties of the ferroferric oxide magnetic powder. Capacitance, and dispersion in the rubber matrix. This results in a tighter bond between the ferroferric oxide and the rubber matrix, thereby significantly improving the mechanical properties of the magnetic rubber.

Preferably, the rubber in the magnetic rubber is one or more of natural rubber, nitrile rubber, styrene butadiene rubber and ethylene propylene rubber. Depending on the application requirements of the product, such as oil resistance, chemical resistance, heat resistance and aging resistance, different types of rubber may be used or combined.

Preferably, the ferroferric oxide powder has a particle diameter of 0.2 to 4 um.

Preferably, in terms of parts by mass, the raw material ratio composition is: N41 type NBR 100 parts, particle size 1 um ferroferric oxide powder 70 parts, zinc methacrylate 10 parts, dicumyl peroxide 1.5 parts and three Allyl isocyanurate 2.5 parts.

Preferably, the number of times of the rubber mastication is 3-7 times; the addition of the unsaturated carboxylate, the addition of the ferroferric oxide magnetic powder or the addition of the vulcanizing agent and the vulcanization accelerator agent each time the rubber is tapped, rolled, and triangular The number of times is 3-7 times.

Preferably, the vulcanization molding comprises placing the rubber compound into a mold and vulcanizing the product into a product on a flat vulcanizer, wherein the vulcanization temperature is 140 to 175 ° C, and the vulcanization time is 10 to 60 min.

Preferably, the magnetization is performed by placing the vulcanized molded blank into a magnetic field strength of 12,000 to 15000 Oe. The line is magnetized and the magnetization time is 18 to 25 minutes.

Preferably, the ferroferric oxide magnetic powder is dried in a vacuum environment at a temperature of 50 to 60 ° C for 2 to 6 hours before use; the weight ratio of the vulcanizing agent and the vulcanization accelerator is 1:1.2 to 1:1.8; Helps to remove moisture and ensure that the basic mechanical properties of the magnetic rubber are not affected.

The unsaturated carboxylic acid salt is added by direct addition; or the unsaturated carboxylic acid salt is added by in-situ formation; the in-situ formation method is added by adding metal during the rubber-coated roll at the open mill Or hydroxide and unsaturated carboxylic acid, in situ formation of unsaturated carboxylate, wherein the volume ratio of unsaturated carboxylic acid to metal oxide or hydroxide is 2.12 ~ 7.31:1; volume unit is ml; mass The unit is g; the unsaturated carboxylic acid is one or more of maleic acid, acrylic acid, methacrylic acid; the metal oxide or hydroxide is zinc oxide, magnesium oxide, magnesium hydroxide, One or more of aluminum hydroxide. The unsaturated carboxylate will form an ionic crosslink bond in the rubber matrix under the action of the high temperature of the alkyl peroxide vulcanizing agent, and the interaction between the carbonyl group on the unsaturated carboxylate and the ferric oxide can improve the magnetic powder. The distribution in the rubber matrix, so that the ferroferric oxide magnetic powder is more tightly combined with the rubber matrix, significantly improving the mechanical properties of the magnetic rubber.

The preparation method of the magnetic rubber reinforced by the unsaturated carboxylate comprises the following steps:

1) Rubber: At room temperature, the rubber is first masticated 3 to 7 times on the open mill; then the unsaturated carboxylate and ferroferric oxide magnetic powder are added one by one in order, and the tapping is performed 3 to 7 times respectively. , roll, triangle, until the mixing is uniform; finally add vulcanizing agent and vulcanization accelerator for mixing, 3 to 7 times of tapping, winding, triangle bag, until the mixing is uniform, filming, cooling , get the rubber mixture;

2) vulcanization molding: the mixture is placed in a mold, and is vulcanized into a product on a flat vulcanizer, wherein the vulcanization temperature is 140 to 175 ° C, and the vulcanization time is 10 to 60 min;

3) Magnetization: The vulcanized molded blank is magnetized under the condition of a magnetic field strength of 12,000 to 15000 Oe, and the magnetization time is 18 to 25 minutes.

Preferably, the temperature of the vulcanization molding in the step 2) is from 155 to 170 °C.

The magnetic powder used in the present invention is a micron-sized ferroferric oxide powder having high magnetic permeability, low coercive force, high saturation magnetic flux density and saturation magnetization, and low magnetic loss and electrical loss. Under the action of the external magnetic field, the easy magnetization axes of the magnetic particles in the rubber are easily aligned in the direction of the magnetic field, thereby obtaining a magnetic rubber having a high saturation magnetic flux density and saturation magnetization. The particle size of the magnetic powder has a great influence on the magnetic rubber: the particle size of the magnetic powder is too small, that is, less than 100 nm, and the formation of the magnetic rubber is difficult because the magnetic powder is easy to agglomerate and requires chemical treatment to modify the surface, thereby causing complicated process and high cost; If the particle size is larger than 5 um, the coordination between the magnetic powder and the rubber is difficult, so that the rubber matrix cannot cover the entire surface of the magnetic powder, resulting in a lower saturation magnetic flux density and saturation magnetization.

Compared with the prior art, the present invention has the following advantages:

1. The magnetic rubber of the present invention is combined with an alkyl peroxide vulcanizing agent by introducing an unsaturated carboxylic acid salt, and is tightly bonded to the rubber matrix by an ion crosslinking bond, and at the same time, a metal ion cluster in the ion crosslinking bond, The carbonyl group interacts with the magnetic powder to improve the compatibility between the magnetic powder and the rubber matrix, and the dispersibility of the magnetic powder in the rubber matrix, so that the magnetic powder and the rubber matrix are more tightly combined, and the mechanical properties are significantly improved. The tensile strength and tear strength of the magnetic rubber are increased by 2 to 6 times, which makes up for the shortcomings of the existing magnetic rubber.

2. The magnetic rubber produced by the invention has significant improvement in mechanical properties, and its magnetic properties are basically unchanged. It can be widely used in applications such as electronic appliances and automotive parts, which have high strength requirements and certain magnetic properties. field.

3. The processing method of the magnetic rubber of the invention is simple, the equipment used is generally used, less, and the cost is low.

DRAWINGS

1 is a hysteresis diagram of the magnetic rubber obtained in Example 6 and Comparative Example 3.

2 is a scanning electron micrograph of the magnetic rubber obtained in Comparative Example 3.

3 is a scanning electron micrograph of the magnetic rubber obtained in Example 4.

4 is a scanning electron micrograph of the magnetic rubber obtained in Example 3.

detailed description

The present invention will be further specifically described below in conjunction with the accompanying drawings and embodiments, but the embodiments of the invention are not limited thereto. The test methods related to the embodiments of the present invention are described as follows:

In Tables 1 and 2, the tensile properties are tested according to GB/T528-1998; the right-angle tear strength is tested according to GB/T529-1999; the saturation magnetic induction and hysteresis curves are performed by vibrating sample magnetometer (VSM). test.

Scanning electron micrographs of the examples and comparative examples of the present invention were measured by a XL-30FEG scanning electron microscope of Philips, Netherlands, and the magnification was 10,000 times.

Example 1

Nitrile rubber was selected as the base rubber (Model N41, China National Petroleum Corporation, Lanzhou Petrochemical Company, acrylonitrile content of 28-30%). First, the nitrile rubber (100g) was masticated 7 times on the mill; secondly, zinc methacrylate powder (5g) was added to the nitrile rubber, and the rubber was tapped, rolled, and triangled three times until mixing. Uniform; then add the weighed and dried ferroferric oxide powder (100g), and also tapping, rolling, and triangulating three times until the mixing is uniform; then adding the curing agent dicumyl peroxide ( 1.5 g) and a vulcanization accelerator, triallyl isocyanurate (2.5 g), until the kneading was uniform; finally, the roll pitch was adjusted to 0.4 cm, and the film was cooled. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at 170 ° C for 10 min. The obtained rubber product is magnetized under the condition that the magnetic field strength is 12000 Oe, and the soft magnetic magnetic rubber is obtained after magnetization.

Example 2

Nitrile rubber was selected as the base rubber (Model: Nandi 3655, Zhenjiang Nandi Chemical Co., Ltd., acrylonitrile content was 36%). First, the nitrile rubber (100 g) was masticated 6 times on an open mill; secondly, zinc oxide powder (3.45 g) was added to the nitrile rubber while methacrylic acid (7.32 ml) was injected into the nitrile rubber with a syringe. , respectively, tapping, rolling, and triangleing for 4 times until the mixing is uniform; then adding the weighed and dried ferroferric oxide powder (85g), and also tapping, rolling, and triangleping 4 times each. Until the mixing is uniform; then adding the vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (1.5 g) and the vulcanization accelerator isocyanurate isocyanurate (3.0 g), until the mixing is uniform; finally, the roll distance is adjusted to 0.5 cm, and the film is cooled. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at 165 ° C for 16 min. The rubber article obtained above was subjected to magnetization under the condition that the magnetic field strength was 12,000 Oe, and after softening, a soft magnetic magnetic rubber was obtained.

Example 3

Nitrile rubber was selected as the base rubber (Model: Nandi 4155, Zhenjiang Nandi Chemical Co., Ltd., acrylonitrile content was 41%). First, the natural rubber (100g) was masticated five times on the mill; secondly, magnesium methacrylate powder (15g) was added to the natural rubber, and the rubber was tapped, rolled, and triangled five times until the mixture was uniform; Then add the weighed and dried ferroferric oxide magnetic powder (70g), and also carry out tapping, rolling, and triangleing 5 times until the mixing is uniform; then adding the vulcanizing agent diisopropyl benzoate (1.8g) And the vulcanization accelerator, triallyl isocyanurate (3.0 g), until the kneading was uniform; finally, the roll distance was adjusted to 0.6 cm, and the film was cooled. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at a temperature of 160 ° C for 22 min. The rubber product obtained above is magnetized under the condition that the magnetic field strength is 15000 Oe, and the soft magnetic magnetic rubber is obtained after magnetization.

Example 4

Nitrile rubber was selected as the base rubber (Model N41, China National Petroleum Corporation, Lanzhou Petrochemical Company, acrylonitrile content of 28-30%). First, the nitrile rubber (100g) was masticated 7 times on the mill; secondly, zinc acrylate powder (10g) was added to the nitrile rubber, and the rubber was tapped, rolled, and triangled four times until the mixture was uniform; Then add the weighed and dried ferroferric oxide magnetic powder (70g), and then tap, roll and triangle three times until the mixing is uniform; then add the vulcanizing agent 2,5-dimethyl-2 , 5-bis(tert-butylperoxy)hexane (1.8 g) and vulcanization accelerator triallyl isocyanurate (3.0 g) until homogeneously kneaded; finally, the roll distance was adjusted to 0.4 cm. ,cool down. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at 170 ° C for 10 min. The rubber product obtained above was subjected to magnetization under the condition that the magnetic field strength was 15,000 Oe, and after softening, a soft magnetic magnetic rubber was obtained.

Example 5

Nitrile rubber was selected as the base rubber (Model: Nandi 3655, Zhenjiang Nandi Chemical Co., Ltd., acrylonitrile content was 36%). First, the nitrile rubber (100 g) was firstly kneaded 6 times on an open mill; secondly, zinc oxide powder (1.73 g) was added to the nitrile rubber while methacrylic acid (3.67 ml) was injected into the nitrile rubber with a syringe. , respectively, tapping, rolling, and triangleing 5 times until the mixing is uniform; then adding the weighed and dried ferroferric oxide powder (70g), and also tapping, rolling, and triangleping 4 times each. , until the mixing is uniform; then add the vulcanizing agent diisopropyl benzoate (1.8g) and the vulcanization accelerator isocyanurate isocyanate (3.0g) until the mixing is uniform; finally, the roll distance is adjusted to 0.5 Cm film, cooling. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at 165 ° C for 16 min. The rubber product obtained above is magnetized under the condition that the magnetic field strength is 15000 Oe, and the soft magnetic magnetic rubber is obtained after magnetization.

Example 6

Nitrile rubber was selected as the base rubber (Model: Nandi 4155, Zhenjiang Nandi Chemical Co., Ltd., acrylonitrile content was 41%). First, the natural rubber (100g) was masticated five times on the mill; secondly, the magnesium acrylate powder (10g) was added to the natural rubber, and the rubber was tapped, rolled, and triangled four times until the mixture was evenly mixed; Add the weighed and dried ferroferric oxide powder (77g), and then tap, roll and triangle three times until the mixing is uniform; then add the vulcanizing agent dicumyl peroxide (1.8g) and The vulcanization accelerator is triallyl isocyanurate (3.0 g) until the kneading was uniform; finally, the roll pitch was adjusted to 0.6 cm, and the film was cooled. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at a temperature of 160 ° C for 22 min. The rubber product obtained above is magnetized under the condition that the magnetic field strength is 15000 Oe, and the soft magnetic magnetic rubber is obtained after magnetization.

Comparative example 1

Nitrile rubber was selected as the base rubber (Model N41, China National Petroleum Corporation, Lanzhou Petrochemical Company, acrylonitrile content of 28-30%). First, the nitrile rubber (100g) was plasticized 7 times on the open mill; secondly, the weighed and dried ferroferric oxide powder (100g) was added, and the rubber was cut, rolled, and triangled three times until mixed. Uniformly; followed by the addition of the vulcanizing agent diisopropyl benzoate (1.5g) and the vulcanization accelerator isocyanurate isocyanate (2.5g) until the mixing is uniform; finally, the roll distance is adjusted to 0.4cm ,cool down. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at 170 ° C for 10 min. The rubber product obtained above is magnetized under the condition that the magnetic field strength is 12000 Oe, and the soft magnetic magnetic rubber is obtained after magnetization.

Comparative example 2

Nitrile rubber was selected as the base rubber (Model: Nandi 3655, Zhenjiang Nandi Chemical Co., Ltd., acrylonitrile content was 36%). First, the nitrile rubber (100g) was masticated 6 times on the open mill; secondly, the ferroferric oxide powder (85g) which was weighed and dried was added, and the rubber tapping, rolling and triangle were also carried out 4 times until mixing. Uniformly refined; then added vulcanizing agent 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane (1.5 g) and a vulcanization accelerator triallyl isocyanurate (3.0 g) until homogeneously kneaded; finally, The roll distance was adjusted to 0.5 cm and the film was cooled. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at 165 ° C for 16 min. The rubber article obtained above was subjected to magnetization under the condition that the magnetic field strength was 12,000 Oe, and after softening, a soft magnetic magnetic rubber was obtained.

Comparative example 3

Nitrile rubber was selected as the base rubber (Model: Nandi 4155, Zhenjiang Nandi Chemical Co., Ltd., acrylonitrile content was 41%). First, the natural rubber (100g) is masticated five times on the mill; secondly, the ferroferric oxide powder (70g) which has been weighed and dried is added, and the rubber is cut, rolled, and triangled five times until mixing. Uniform; then adding the vulcanizing agent diisopropyl benzoate (1.8g) and the vulcanization accelerator isocyanurate isocyanate (3.0g) until the mixing is uniform; finally, the roll distance is adjusted to 0.6cm, cool down. The cooled mixture was placed in a mold, placed on a flat vulcanizer, and vulcanized at a temperature of 160 ° C for 22 min. The rubber product obtained above is magnetized under the condition that the magnetic field strength is 15000 Oe, and the soft magnetic magnetic rubber is obtained after magnetization.

Table 1: Magnetic and physical properties of the magnetic rubber of the examples

Table 2: Magnetic and physical properties of the comparative magnetic rubber

	Comparative example 1	Comparative example 2	Comparative example 3
Tensile strength / MPa	2.76	2.65	2.51
Tear strength / KN·m -1	9.12	8.98	8.86

Saturation magnetization / emu / g	37.74	35.16	31.74
Elongation at break /%	172.13	148.02	147.86

It can be seen from the results of the above Table 1 and Table 2 and the comparative examples that the tensile strength of the magnetic rubber prepared by the unsaturated carboxylate reinforcement can reach 6.83 MPa or more, and the tensile strength is relatively good. The ratio is increased by 2 to 6 times, and the tear strength is also greatly improved to 13.98 KN·m ^-1 or more, and the best test result of Comparative Example 1 is 9.12 KN·m ^-1 . At the same time, its saturation magnetization is above 29.03emu/g.

By comparison of the three groups of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, it can be seen that the saturation magnetization in the examples is comparable to that of the corresponding comparative examples. Slightly lower. This is because the mass percentage of the magnetic powder in the magnetic rubber is lowered due to the addition of the unsaturated carboxylate. In Example 6 and Comparative Example 3, the mass percentage of the magnetic powder in the composite material was 41.17%, and the corresponding saturation magnetizations were 31.73 emu/g and 31.74 emu/g, respectively. 1 is a hysteresis diagram of the magnetic rubber obtained in Example 6 and Comparative Example 3. Figure 1 is obtained by testing the vibrating sample magnetometer of the PPMS-9 comprehensive physical property measurement system. It can also be seen from Fig. 1 that the hysteresis curves of Example 6 and Comparative Example 3 substantially completely overlap. This indicates that the addition of the unsaturated carboxylate does not affect the saturation magnetization of the magnetic rubber, and the magnetic properties of the magnetic rubber produced by the present invention mainly depend on the mass percentage of the magnetic powder in the composite. This means that as long as the magnetic powder is kept at the mass percentage of the composite material, an appropriate amount of unsaturated carboxylic acid salt is added to the rubber matrix to obtain a magnetic rubber which has excellent mechanical properties and magnetic properties.

2 is a scanning electron micrograph of the magnetic rubber obtained in Comparative Example 3. 3 is a scanning electron micrograph of the magnetic rubber obtained in Example 4. 2 and 3, it can be clearly observed that the addition of the unsaturated carboxylate can improve the compatibility between the magnetic powder and the rubber matrix and increase the dispersion of the magnetic powder in the rubber matrix. 4 is a scanning electron micrograph of the magnetic rubber obtained in Example 3. 3 and 4, it can be observed that as the amount of the unsaturated carboxylic acid increases, the binding between the magnetic powder and the rubber matrix is tight, and the dispersibility of the magnetic powder in the rubber matrix becomes better.

By comparison of the three groups of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, it can be seen that the elongation at break is slightly increased after the addition of the unsaturated carboxylate. The increase is due to the improvement of the interface between the magnetic powder and the rubber matrix by the unsaturated carboxylate.

The magnetic rubber produced by the present invention has such excellent comprehensive properties, mainly in:

1) through the strong interaction between the metal ion cluster in the unsaturated carboxylate, the carbonyl group and the ferroferric oxide magnetic powder, thereby improving the compatibility of the magnetic powder with the rubber matrix and improving the dispersion of the magnetic powder in the rubber matrix, and further The mechanical properties of the magnetic rubber are significantly improved without affecting the magnetic properties of the ferroferric oxide particles. At the same time, the magnetic properties of the magnetic rubber are uniform and stable due to the uniform dispersion of the ferroferric oxide magnetic powder in the rubber.

2) Under the action of peroxide, the unsaturated carboxylate undergoes self-polymerization and grafting reaction in the rubber matrix during the vulcanization process to form an ionic cross-linking bond, thereby improving the mechanical properties of the rubber.

3) A suitable particle size of ferroferric oxide magnetic powder is selected, so that the particle size is too large, which tends to cause a decrease in performance; and the magnetic powder particle size is too small, prone to agglomeration, and also leads to poor performance.

Claims (10)

1. A magnetic rubber reinforced by an unsaturated carboxylate, characterized in that the raw material ratio composition is: by mass fraction:

   Rubber: 100 parts;

   Micron-sized ferroferric oxide powder: 70-100 parts;

   Unsaturated carboxylate: 5 to 15 parts;

   Vulcanizing agent: 0.5 to 2.5 parts;

   Vulcanization accelerator: 0.83 to 4.16 parts;

   The unsaturated carboxylate is one or more of zinc methacrylate, magnesium methacrylate, zinc acrylate and magnesium acrylate;

   The vulcanizing agent is an alkyl peroxide;

   The micron-sized ferroferric oxide magnetic powder has a particle diameter of 0.1 to 5 um;

   The vulcanization accelerator is one or more of triallyl cyanurate, triallyl isocyanurate and 1,2-polybutadiene;

   During preparation, at room temperature, the rubber is first masticized on the open mill, the unsaturated carboxylate is added, and the rubber is tapped, rolled, and triangled until the mixture is evenly mixed; then the ferroferric oxide powder is added to perform tapping. Winding, triangle; adding vulcanizing agent and vulcanization accelerator until the mixing is uniform, and the film is cooled and cooled to obtain a rubber compound; then the rubber is vulcanized and molded; finally, magnetization is performed to obtain a magnetic rubber.
2. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the alkyl peroxide is dicumyl peroxide, 2,5-dimethyl-2,5 - bis(tert-butylperoxy)hexane, 1,3-bis(tert-butylperoxy)hexane, benzoyl peroxide and 1,1-di-tert-butylperoxy-3,3,5 One or more of trimethylcyclohexane.
3. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the rubber in the magnetic rubber is one of natural rubber, nitrile rubber, styrene butadiene rubber and ethylene propylene rubber. Or a variety.
4. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the ferroferric oxide powder has a particle diameter of 0.2 to 4 μm.
5. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the raw material ratio composition is: N41 type NBR 100 parts, particle size 1 um ferroferric oxide powder 70 parts, methyl 10 parts of zinc acrylate, 1.5 parts of dicumyl peroxide and 2.5 parts of triallyl isocyanurate.
6. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the number of times of rubber mastication is 3-7 times; adding an unsaturated carboxylate, adding a ferroferric oxide powder or After the vulcanizing agent and the vulcanization accelerator are added, the number of times of tapping, rolling, and triangulation is 3-7 times.
7. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the vulcanization molding is performed by placing the rubber compound into a mold and vulcanizing it into a product on a flat plate vulcanizer, wherein the vulcanization is performed. The temperature is 140 to 175 ° C, and the curing time is 10 to 60 minutes.
8. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the magnetization is performed by subjecting the vulcanized molded blank to a magnetic field strength of 12,000 to 15,000 Oe for magnetization. The magnetization time is 18 to 25 minutes.
9. The magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, wherein the ferroferric oxide magnetic powder is dried in a vacuum environment at a temperature of 50 to 60 ° C for 2 to 6 hours before use; The weight ratio of the vulcanizing agent and the vulcanization accelerator is 1:1.2 to 1:1.8;

   The unsaturated carboxylic acid salt is added by direct addition; or the unsaturated carboxylic acid salt is added by in-situ formation; the in-situ formation method is added by adding metal during the rubber-coated roll at the open mill Or hydroxide and unsaturated carboxylic acid, in situ formation of unsaturated carboxylate, wherein the volume ratio of unsaturated carboxylic acid to metal oxide or hydroxide is 2.12 ~ 7.31:1; volume unit is ml; mass The unit is g; the unsaturated carboxylic acid is one or more of maleic acid, acrylic acid, methacrylic acid; the metal oxide or hydroxide is zinc oxide, magnesium oxide, magnesium hydroxide, One or more of aluminum hydroxide.
10. The method for preparing a magnetic rubber reinforced by an unsaturated carboxylate according to claim 1, comprising the steps of:

    1) Rubber: At room temperature, the rubber is first masticated 3 to 7 times on the open mill; then the unsaturated carboxylate and ferroferric oxide magnetic powder are added one by one in order, and the tapping is performed 3 to 7 times respectively. , roll, triangle, until the mixing is uniform; finally add vulcanizing agent and vulcanization accelerator for mixing, 3 to 7 times of tapping, winding, triangle bag, until the mixing is uniform, filming, cooling , get the rubber mixture;

    2) vulcanization molding: the mixture is placed in a mold, and is vulcanized into a product on a flat vulcanizer, wherein the vulcanization temperature is 140 to 175 ° C, and the vulcanization time is 10 to 60 min;

    3) Magnetization: The vulcanized molded blank is magnetized under the condition of a magnetic field strength of 12,000 to 15,000 Oe, and the magnetization time is 18 to 25 minutes.

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