CN115536850A - A method for modifying aramid pulp, its reinforced rubber composite material and its preparation method - Google Patents

Abstract

The invention discloses a preparation method of aramid pulp modified rubber, which comprises the following steps: respectively adding aramid pulp, a coupling agent, a fatty acid or aliphatic amide dispersing agent and hydroxypropyl-beta-cyclodextrin into a solvent, wherein the aramid pulp accounts for 15-35wt% of the mass of the solution, the coupling agent accounts for 2-5wt% of the mass of the solution, the fatty acid or aliphatic amide dispersing agent accounts for 2-5wt% of the mass of the solution, and the chitosan hydroxypropyl-beta-cyclodextrin accounts for 1-2.5wt% of the mass of the solution, and stirring to uniformly disperse the aramid pulp, the coupling agent, the fatty acid or aliphatic amide dispersing agent and the hydroxypropyl-beta-cyclodextrin; and standing the mixed solution, and drying at the temperature of 80-120 ℃ for 12-36h to obtain the dried modified aramid pulp material. The aramid pulp modified by the method has obvious effect of improving the mechanical property of the hydrogenated nitrile-butadiene rubber.

Description

A method for modifying aramid pulp, its reinforced rubber composite material and its preparation method

technical field

The invention relates to the technical field of rubber reinforcement, in particular to a preparation method of aramid pulp modified rubber.

Background technique

Nitrile-butadiene rubber (NBR) has the characteristics of oil resistance and easy modification, and is widely used in various friction materials such as seals, piston rings, and water-lubricated bearings, but its low wear resistance limits wider applications. Reinforcing modified rubber with inorganic fillers, organic fillers and fibers is a simple and effective method to improve its mechanical properties and friction properties.

Aramid pulp is a differentiated product of aramid fiber, which not only retains most of the excellent properties of aramid fiber, such as heat resistance, wear resistance and dimensional stability, but also has some characteristics different from aramid fiber long fiber Physical properties, such as the surface is piled up with fluffy microfibrils, and the axial end of the fiber is fibrillated into a needle-like shape, so that the specific surface area is huge, so the potential contact surface with the reinforced matrix is large.

In the prior art, after the aramid pulp is added to the hydrogenated nitrile rubber compound, the effect of improving its mechanical properties is not ideal.

Contents of the invention

The purpose of the present invention is to provide a method for modifying aramid pulp, its reinforced rubber composite material and its preparation method, so as to solve one or more of the above-mentioned problems in the prior art.

On the one hand, the present invention provides a kind of preparation method of aramid pulp modified rubber, comprising the following steps:

Aramid pulp, coupling agent, fatty acid or aliphatic amide dispersant and hydroxypropyl-β-cyclodextrin are respectively added to the solvent, the aramid pulp accounts for 15-35wt% of the solution mass, The coupling agent accounts for 2-5wt% of the solution mass, the fatty acid or aliphatic amide dispersant accounts for 2-5wt% of the solution mass, and the shell hydroxypropyl-β-cyclodextrin accounts for the 1-2.5wt% of the solution mass, stir to disperse evenly;

The above mixed solution is left to stand, and dried at 80 to 120° C. for 12-36 hours to obtain a dried modified aramid pulp material.

In some embodiments, the coupling agent is one of KH-590, KH-580, KH-570, KH-560 or KH-550.

In some embodiments, the solvent is one or more of absolute ethanol, methanol, acetone, tetrahydrofuran or alkyl halides.

In some embodiments, the fatty acid or aliphatic amide dispersant is vinyl bisstearamide or monoglyceride stearate.

On the other hand, the present invention provides an aramid pulp reinforced rubber composite material, comprising 100 parts by mass of hydrogenated nitrile rubber, 20 to 50 parts of carbon black, 1 to 5 parts of diisoperoxide Propylbenzene and 0.5 to 2 parts of modified aramid.

In some embodiments, by mass parts, it includes 100 parts of hydrogenated nitrile rubber, 30 parts of carbon black, 1.5 parts of dicumyl peroxide and 1 part of modified aramid fiber.

In another aspect, the present invention provides a kind of preparation method of aramid pulp reinforced rubber composite material, comprising:

Banburying step: the starting temperature of banburying is 60°C, and the rotor speed is 60r/min; when banburying for 0 min, add hydrogenated nitrile rubber; when banburying for 1 min, add half of the carbon black and half of the modified aramid ; When banburying for 2.5 minutes, the other half of carbon black and modified aramid fiber; when banburying for 4.0 minutes, open the top bolt to clean in sequence, and when banburying for 6.5 minutes, remove glue;

Smelting steps: when the roller distance of the mill is 1.0mm, add dicumyl peroxide, and tap the rubber 4 times; when the roller distance of the mill is 0.2mm, make triangular bags 5 times; mm, unload and park.

Beneficial effects of the present invention:

By adding the aramid pulp modified by the method of the invention, the effect of improving the mechanical properties of the hydrogenated nitrile rubber is remarkable.

Description of drawings

Fig. 1 is the performance data graph of the modulus stress of formula 1#, 2# and 3#.

detailed description

The present invention will be further described below in conjunction with embodiment. The following examples are only used to illustrate the performance of the present invention more clearly, and should not be limited to the following examples.

Example 1

A preparation method of aramid pulp modified rubber, comprising the following steps:

Add 225g of aramid pulp, 30g of coupling agent KH-550, 30g of monoglyceride stearate and 15g of hydroxypropyl-beta-cyclodextrin in 700g of solvent respectively, the aramid pulp accounts for the 22.5wt% of the solution quality, the coupling agent KH-550 accounts for the 3wt% of the solution quality, the described monoglyceride stearate accounts for the 3wt% of the solution quality, and the shell hydroxypropyl-β-cycloglutamate Essence accounts for 1.5wt% of this solution quality, stirs to make it disperse evenly;

The above mixed solution was left to stand and dried at 100° C. for 24 hours to obtain a dried modified aramid pulp material.

A preparation method of aramid pulp reinforced rubber composite material, comprising:

Banburying step: the initial temperature of banburying is 60°C, and the rotor speed is 60r/min; when banburying for 0min, add 1Kg of hydrogenated nitrile rubber; when banburying for 1min, add 250g of carbon black and -10g of Modified aramid fiber; when banburying for 2.5 minutes, 250g of carbon black and 10g of modified aramid pulp; when banburying for 4.0min, open the top bolt to clean in sequence, and when banburying for 6.5min, remove glue;

Opening process: when the roller distance of the mill is 1.0mm, add 50g of dicumyl peroxide, and tap rubber 4 times; when the roller distance of the mill is 0.2mm, make triangular bags 5 times; When the distance is 1.6mm, the film is unloaded and parked.

Comparative example 1:

A preparation method of aramid pulp reinforced rubber composite material, comprising:

Banburying step: the initial temperature of banburying is 60°C, and the rotor speed is 60r/min; when banburying for 0min, add 1Kg of hydrogenated nitrile rubber; when banburying for 1min, add 250g of carbon black and -10g of Modified aramid fiber; when banburying for 2.5 minutes, 250g of carbon black; when banburying for 4.0 minutes, open the top bolt to clean in sequence; when banburying for 6.5 minutes, remove glue;

Opening process: when the roller distance of the mill is 1.0mm, add 50g of dicumyl peroxide, and tap the rubber 4 times; when the roller distance of the mill is 0.2mm, make triangular bags 5 times; When the distance is 1.6mm, the film is unloaded and parked.

Comparative example 2:

A preparation method of aramid pulp reinforced rubber composite material, comprising:

Banburying step: the initial temperature of banburying is 60°C, and the rotor speed is 60r/min; when banburying for 0min, add 1Kg of hydrogenated nitrile rubber; when banburying for 1min, add 250g of carbon black and -10g of Modified aramid fiber; when banburying for 2.5 minutes, 250g of carbon black and 10g of unmodified aramid pulp; when banburying for 4.0min, open the top bolt to clean in sequence, and when banburying for 6.5min, remove glue;

Opening process: when the roller distance of the mill is 1.0mm, add 50g of dicumyl peroxide, and tap the rubber 4 times; when the roller distance of the mill is 0.2mm, make triangular bags 5 times; When the distance is 1.6mm, the film is unloaded and parked.

Comparative example 1 is marked as formula 1#, comparative example 2 is marked as formula 2#, and embodiment 1 is marked as formula 3#. Referring to the standard GB/T528-1998, use the electronic tensile machine produced by Zwick Company of Germany to test the tensile strength, constant tensile stress and elongation at break of rubber 1#, 2# and 3#, and the tear strength is in accordance with GB/T 529- Measured in 1999. Shore A hardness is measured according to GB/T 531-1999.

The specific results are as follows:

formula 1# 2# 3# Tensile strength/MPa 19.6 20.9 22.5 Elongation at break/% 583 590 613 Stress at modulus (50%)/MPa 1.4 2.2 3.7 Stress at modulus (100%)/MPa 2.0 3.3 4.8 Stress at modulus (200%)/MPa 6.1 7.0 8.8 Stress at modulus (300%)/MPa 11.7 11.0 13.1 Tear strength/N·mm-1 64 68 75 hardness 64 67 69

From the table above and Figure 1, it can be seen that:

Compared with 2# adding aramid pulp and 1# without adding aramid pulp, the tensile strength, elongation at break, 50% modulus, 100% modulus, 200% modulus of hydrogenated nitrile rubber The stress, tear strength and hardness have increased, but the increase is not obvious, and the 300% modulus stress has little difference; it may be because the surface of aramid pulp contains amino groups, sulfonic acid groups, amido groups and carboxylic acid groups. Sexual groups make the interaction between aramid pulp and hydrogenated nitrile rubber poor, while aramid pulp interacts, entangles and flocculates into coils, making it poorly dispersed in hydrogenated nitrile rubber.

Compared with 3# adding modified aramid pulp and 2# adding unmodified aramid pulp, the tensile strength, elongation at break, 50% modulus stress, 100% modulus stress, 200% modulus, 300% modulus, tear strength, and hardness were significantly improved; probably due to the addition of hydroxypropyl-β-cyclodextrin material to the modified aramid pulp, which has an external Hydrophilic internal lipophilic characteristics, can be coated with monoglyceride stearate in hydroxypropyl-β-cyclodextrin, and the external solidified on the surface of aramid pulp through covalent bonds, the modified aramid fiber Add hydrogenated nitrile rubber to refining, during the refining process, the wrapped monoglyceride stearate with dispersing effect is gradually released, and can effectively improve the interaction between aramid pulp and hydrogenated nitrile rubber, and improve the quality of aramid fiber Dispersibility of pulp in hydrogenated nitrile rubber.

In summary, by adding the aramid pulp modified by the method of the present invention, the effect of improving the mechanical properties of the hydrogenated nitrile rubber is remarkable.

The above statement is only the preferred mode of the present invention, and it should be pointed out that for those of ordinary skill in the art, without departing from the creative concept of the present invention, some modifications and improvements can also be made, and these should also be regarded as the present invention. within the scope of protection.

Claims (7)

1. a method for modifying aramid pulp, is characterized in that, comprises the following steps: Aramid pulp, coupling agent, fatty acid or aliphatic amide dispersant and hydroxypropyl-β-cyclodextrin are respectively added to the solvent, the aramid pulp accounts for 15-35wt% of the solution mass, The coupling agent accounts for 2-5wt% of the solution mass, the fatty acid or aliphatic amide dispersant accounts for 2-5wt% of the solution mass, and the shell hydroxypropyl-β-cyclodextrin accounts for the 1-2.5wt% of the solution mass, stir to disperse evenly; The above mixed solution is left to stand, and dried at 80 to 120° C. for 12-36 hours to obtain a dried modified aramid pulp material. 2. the preparation method of a kind of aramid pulp modified rubber according to claim 1, is characterized in that, described coupling agent is KH-590, KH-580, KH-570, KH-560 or KH- One of 550. 3. the preparation method of a kind of aramid pulp modified rubber according to claim 1, is characterized in that, described solvent is one or more in dehydrated alcohol, methyl alcohol, acetone, tetrahydrofuran or halogenated alkanes. 4. the preparation method of a kind of aramid pulp modified rubber according to claim 2 is characterized in that, described fatty acid or aliphatic amides dispersant is vinyl bis stearamide or monoglycerol stearate ester. 5. An aramid pulp reinforced rubber composite material, characterized in that, in parts by mass, comprising 100 parts of hydrogenated nitrile rubber, 20 to 50 parts of carbon black, 1 to 5 parts of diisopropyl peroxide Benzene and 0.5 to 2 parts of modified aramid. 6. A kind of aramid pulp reinforced rubber composite material according to claim 5, is characterized in that, in parts by mass, comprises 100 parts of hydrogenated nitrile rubber, 30 parts of carbon black, 1.5 parts of peroxidized Dicumyl and 1 part Modified Kevlar. 7. according to the preparation method of a kind of aramid pulp reinforced rubber composite material described in claim 5 or 6, it is characterized in that, comprising: Banburying step: the starting temperature of banburying is 60°C, and the rotor speed is 60r/min; when banburying for 0 min, add hydrogenated nitrile rubber; when banburying for 1 min, add half of the carbon black and half of the modified aramid ; When banburying for 2.5 minutes, the other half of carbon black and modified aramid fiber; when banburying for 4.0 minutes, open the top bolt to clean in sequence, and when banburying for 6.5 minutes, remove glue; Smelting steps: when the roller distance of the mill is 1.0mm, add dicumyl peroxide, and tap rubber 4 times; when the roller distance of the mill is 0.2mm, make triangular bags 5 times; mm, unload and park.

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