CN116178956B

CN116178956B - Modified PPS, preparation method and application thereof, ferrite/modified PPS plastic magnetic material

Info

Publication number: CN116178956B
Application number: CN202310158270.4A
Authority: CN
Inventors: 熊君; 张鹏杰; 孙威; 王继全; 马斌
Original assignee: Bgrimm Magnetic Materials & Technology Co ltd
Current assignee: Bgrimm Magnetic Materials & Technology Co ltd
Priority date: 2023-02-17
Filing date: 2023-02-23
Publication date: 2023-10-13
Anticipated expiration: 2043-02-23
Also published as: CN116178956A

Abstract

The application provides a modified PPS, a preparation method and application thereof, and a ferrite/modified PPS plastic magnetic material, in particular relates to the technical field of plastic magnetic materials. The modified PPS includes PPS, branched polyethylene, polar graft copolymer, and a lubricant; wherein the branched polyethylene comprises at least one of EBA, EMA, EAA and EEA; the polar graft copolymer comprises POE-g-GMA and/or SEBS-g-MA; the lubricant includes at least one of stearic acid amide, erucic acid amide, and oleic acid amide. The modified PPS provided by the application uses branched polyethylene, so that the impact toughness of the PPS is improved; meanwhile, the polar graft copolymer is added, so that the polarity of PPS can be enhanced, and the PPS can be better mutually fused with a polar or nonpolar system; the addition of the lubricant improves the flowability of PPS and solves the defects of unsatisfactory injection molding and uneven injection molding of products caused by poor flowability of PPS.

Description

Modified PPS, preparation method and application thereof, ferrite/modified PPS plastic magnetic material

The application claims priority from China patent office, application No. 2023101300695, entitled "modified PPS and preparation method and application, ferrite/modified PPS Plastic magnetic Material", filed on App. No. 2023, 02 and 17, the entire contents of which are incorporated herein by reference.

Technical Field

The application relates to the technical field of plastic magnetic materials, in particular to a modified PPS, a preparation method and application thereof, and a ferrite/modified PPS plastic magnetic material.

Background

ferrite/PPS plastic magnetic material: ferrite magnetic powder is taken as a main raw material, evenly mixed with additives such as a binder PPS (polyphenylene sulfide), a lubricant and the like in a high-speed mixer, heated and mixed by a double-screw extruder, granulated to obtain injection molding granules, and a plastic magnetic product is prepared by an injection molding technology and mainly comprises a plastic magnetic motor rotor, a magnetic ring and the like, and is assembled on a micro-special motor.

With the development of social intelligence, the micro-special motor is updated and iterated, the volume is required to be smaller and smaller, and products tend to develop in a high-performance, small-sized and light-weight way, so that the plastic-magnetic material with high magnetic performance needs to be developed. The magnetic properties are proportional to the magnetic powder filling rate, so that the magnetic powder filling amount should be as high as possible under the premise of meeting the process and service performances in order to obtain higher magnetic properties. With the increase of the powder filling rate, the magnetic performance can be greatly improved, but the mechanical performance (including impact toughness, tensile strength and the like) and the flow performance are in a decreasing trend.

The high powder filling rate (more than or equal to 85 wt.%) can greatly reduce the mechanical property of the product due to the shortage of the binder while obtaining the high magnetic property, so that a strong internal stress concentration effect appears in the plastic magnetic product, and further cracking deformation of the product appears. The PPS matrix imparts many excellent properties to the ferrite/PPS plastic-magnetic material, such as good tensile strength properties, high temperature resistance, high dimensional accuracy, chemical stability, etc. However, because PPS is a hard and brittle polymer, its impact toughness is poor, and the main raw material ferrite magnetic powder is also hard and brittle, so that the ferrite/PPS plastic-magnetic material is easy to crack and deform during the processing of injection molding, and after being made into a plastic-magnetic product (such as a plastic-magnetic rotor, a magnetic ring), the plastic-magnetic product is also easy to crack and deform during the use (such as high-speed rotation), resulting in low yield, and limiting the application thereof in some high-end fields or under extreme conditions.

In order to solve the above problems, it is necessary to ensure impact toughness and flowability while improving the magnetic properties of ferrite/PPS plastic magnetic materials to obtain high yield. The prior art mainly comprises the following steps: reducing the magnetic powder content, adding a toughening agent and a lubricant, and modifying the PPS by using EVA (ethylene-vinyl acetate copolymer).

The disadvantages of the above solutions are:

1. the method for reducing the magnetic powder content (the magnetic powder content is less than or equal to 85 wt.%) has the defects that the magnetic performance is reduced due to low magnetic powder content, br is less than or equal to 245mT, and (BH) max is less than or equal to 11.5 kJ.m ^-3 Only can be used as a low-grade product, and the magnetic performance requirement of a high-grade product cannot be met.

2. The method of directly adding the toughening agent and the lubricant has no obvious effect of increasing the impact toughness and the flow property, and can not meet the use requirement of high-performance products. Under the condition of high powder filling rate (more than or equal to 85 wt.%), the toughening agent and the lubricant are directly added according to the prior art, and the problems of injection molding deformation cracking and poor fluidity and molding defects still exist. And the toughening agent and the lubricant have poor compatibility with ferrite magnetic powder and PPS high molecular polymer, and can cause defects of additive precipitation, frosting, reaction with other auxiliary agents, performance reduction and the like.

3. The EVA is used for modifying the PPS, so that the PPS is not suitable for ferrite/PPS plastic magnetic materials, EVA is easily decomposed in the process of processing and modifying the PPS, and the ferrite/PPS plastic magnetic materials have the problems of air holes and performance reduction.

In view of this, the present application has been made.

Disclosure of Invention

The application aims to provide modified polyphenylene sulfide, and aims to solve the technical problems of low magnetic powder content and poor EVA modification effect caused by poor PPS impact toughness and insufficient binding force in the prior art.

In order to solve the technical problems, the application adopts the following technical scheme:

in a first aspect, the present application provides a modified PPS comprising PPS, branched polyethylene, a polar graft copolymer, and a lubricant;

wherein the branched polyethylene comprises at least one of EBA, EMA, EAA and EEA;

the polar graft copolymer comprises POE-g-GMA and/or SEBS-g-MA;

the lubricant includes at least one of stearic acid amide, erucic acid amide, and oleic acid amide.

Optionally, PPS, branched polyethylene, polar graft copolymer, and lubricants;

wherein the branched polyethylene is EBA;

the polar graft copolymer is POE-g-GMA;

the lubricant is stearic acid amide.

Optionally, the modified polypropylene comprises 80-90 parts of PPS, 5-10 parts of branched polyethylene, 3-8 parts of polar graft copolymer and 2-6 parts of lubricant in parts by weight.

Preferably, the composition comprises 85-87 parts of PPS, 6-8 parts of branched polyethylene, 3-5 parts of polar graft copolymer and 2-4 parts of lubricant in parts by weight.

More preferably, it comprises, in parts by weight, PPS86 parts, branched polyethylene 7 parts, polar graft copolymer 4 parts, and lubricant 3 parts.

The second aspect of the application provides a preparation method of the modified PPS, which comprises the steps of uniformly mixing raw materials, and then extruding, granulating and granulating in a double-screw extruder to obtain the modified PPS.

Optionally, the temperature of the extrusion granulation is 290 ℃ to 320 ℃.

Preferably, the extrusion granulation time is 5min-15min.

Optionally, in the double-screw extruder, the temperature of the feed inlet is 275-285 ℃.

Preferably, the outlet temperature is 300-315 ℃.

Preferably, the rotating speed of the double-screw extruder is 20% -50% of the maximum rotating speed, the pressure is 0.4MPa-2.0MPa, and the torque is 20% -70% of the maximum torque.

Optionally, the particle size of the modified PPS is 1mm to 5mm.

The third aspect of the application provides application of the modified PPS in ferrite/PPS plastic magnetic materials.

The fourth aspect of the application provides a ferrite/modified PPS plastic-magnetic material, which comprises the following components in percentage by mass: 85-88 wt.% of the coupling agent surface modified ferrite magnetic powder, 0.068-0.070 wt.% of the antioxidant, and 11.96-14.96 wt.% of the modified pps of the first aspect.

Preferably, the ferrite magnetic powder comprises strontium ferrite bonded magnetic powder.

Preferably, in the ferrite magnetic powder, br is more than or equal to 285mT, and (BH) max is more than or equal to 16.0kJ/m ³ ，MFR≥60g/10min。

Preferably, the ferrite magnetic powder has a particle size of 1.5 μm to 2 μm.

Preferably, the coupling agent comprises a silane coupling agent and/or a titanate coupling agent.

Compared with the prior art, the application has at least the following beneficial effects:

the modified PPS provided by the application uses branched polyethylene, so that the impact toughness of the PPS is improved; meanwhile, the polar graft copolymer is added, so that the polarity of PPS can be enhanced, and the PPS can be better mutually fused with a polar or nonpolar system; the addition of the lubricant improves the flowability of PPS and solves the defects of unsatisfactory injection molding and uneven injection molding of products caused by poor flowability of PPS. The modified PPS has good processability and mechanical properties, high strength, good toughness, easy processing and molding, good chemical stability, oxidation resistance and safe and reliable use, and can be widely used for manufacturing various ferrite/PPS plastic magnetic material products.

The preparation method of the modified PPS provided by the application has the advantages of continuous process and high degree of mechanization, and is suitable for large-scale industrial production.

The application of the modified PPS in ferrite/PPS plastic magnetic material provides a binder with better performance for the plastic magnetic material, improves the powder filling rate in the plastic magnetic material, ensures the improvement of the magnetic performance of the plastic magnetic material, reduces the volume of a magnet under the same magnetic flux density, and promotes the development of downstream industries.

The ferrite/modified PPS plastic-magnetic material provided by the application has the advantages that the magnetic powder content is increased to 85-88 wt%, the impact toughness is increased by 30%, and the magnetic powder content reaches 8.8kJ/m ² The method comprises the steps of carrying out a first treatment on the surface of the Meanwhile, the melt flow rate of the ferrite/modified PPS plastic magnetic material is improved by 20 percent and reaches 224g/10min, and the ferrite/modified PPS plastic magnetic material is improvedThe mechanical property and the yield of the ferrite/modified PPS plastic-magnetic material are improved. The magnetic property and mechanical property (impact toughness and tensile strength) of the ferrite/modified PPS plastic-magnetic material reach the standard TP-S78 of the household field, and the ferrite/PPS plastic-magnetic material is the highest level of the property of the ferrite/PPS plastic-magnetic material produced in batch at present.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly and completely described in the following in conjunction with the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the application generally described and illustrated herein may be arranged and designed in a wide variety of different configurations.

With the continuous development of technology, related products and parts of emerging industries such as mobile phones, computers and automobiles are developed towards light, thin and miniaturized directions, and meanwhile, more intelligent functions are given to the products, so that the heating value of the electronic products is increased, and further, the magnetic materials are required to have a higher use temperature range. Therefore, the application of ferrite/PPS plastic magnetic material using PPS as the binder is getting more and more attention. The ferrite/PPS plastic magnetic material is suitable for common places where nylon plastic magnetic materials are applied, is more suitable for high-temperature, high-humidity and high-corrosiveness environments, and is widely used in mechanical arms of computer hard disks, mobile phones, automobiles, white household appliances, executive components for electric appliances and high-end equipment manufacturing industries.

With the development of social intelligence, the micro-special motor is updated and iterated, the volume is required to be smaller and smaller, and products tend to develop in a high-performance, small-sized and light-weight way, so that the plastic-magnetic material with high magnetic performance needs to be developed. Due to the improvement of magnetic performance, the same magnetic flux density is generated, the volume of the magnet is reduced, and the product future development trend is met.

The magnetic property of the plastic magnetic material is derived from a main formula system of magnetic powder, and the mechanical property (strength, toughness and the like), the thermal stability and the fluidity are derived from a binder system. The high powder filling rate (more than or equal to 85 wt.%) can greatly reduce the mechanical property of the product due to the shortage of the binder while obtaining the high magnetic property, so that a strong internal stress concentration effect appears in the plastic magnetic product, and further cracking deformation of the product appears. The PPS matrix imparts many excellent properties to the ferrite/PPS plastic-magnetic material, such as good tensile strength properties, high temperature resistance, high dimensional accuracy, chemical stability, etc. However, because PPS is a hard and brittle polymer, its impact toughness is poor, and the main raw material ferrite magnetic powder is also hard and brittle, so that the ferrite/PPS plastic-magnetic material is easy to crack and deform during the processing of injection molding, and after being made into a plastic-magnetic product (such as a plastic-magnetic rotor, a magnetic ring), the plastic-magnetic product is also easy to crack and deform during the use (such as high-speed rotation), resulting in low yield, and limiting the application thereof in some high-end fields or under extreme conditions.

The flowability of injection molded pellets is also a very critical technical indicator in injection molding. Injection molding pellets are intermediate semi-finished products of plastic magnetic material products, and have high viscosity after polymer melting in extrusion granulation and injection molding processes, and the polymer melt must rub against the surface of processing machinery when passing through a runner such as a narrow slit and a gate. When the fluidity is too low, a higher advancing pressure is required, equipment is easy to damage, and the defects of reduced surface magnetic flux, insufficient mold filling, rough surface and the like exist. Conversely, too high fluidity can affect the mechanical property of the material to be reduced, so that the material overflows, and the product becomes brittle and even cracks. Under the condition of high powder filling rate, the interaction among filler particles is enhanced, the orientation resistance of the magnetic powder in a magnetic field is increased, the viscosity of the system is increased, and the fluidity is reduced. Since the fluidity of ferrite magnetic powder is usually much lower than that of PPS additive, too high a magnetic powder loading amount will increase the viscosity of ferrite/PPS mixture system, and the fluidity (MFR) will be poor, often resulting in an increase in injection pressure, which makes magnet molding difficult; the rotation of the magnetic powder particles is limited, so that the orientation degree of the magnetic powder is low, and the magnetic flux is reduced; the degradation of the processing characteristics causes problems such as rough surface of the magnet, air holes or voids in the magnet, and the like, thereby affecting the processing and molding quality of the product.

Therefore, while improving the magnetic properties of ferrite/PPS plastic-magnetic materials, it is also necessary to ensure impact toughness and flowability to obtain high yield. How to solve the problem that the impact toughness and the flow property of the material are reduced under the condition of high powder filling rate (more than or equal to 85 wt.%), the plastic-magnetic material with the comprehensive properties of high magnetic property, high toughness and high fluidity is a research hot spot and is also a technical difficulty in the plastic-magnetic industry.

the polar graft copolymer comprises POE-g-GMA and/or SEBS-g-MA;

In the modified PPS, branched polyethylene is used as a toughening agent to improve the toughness of the PPS material. The branched polyethylene modified PPS toughening is a technical means for improving the impact strength of the blend by melt blending a small amount of branched polyethylene and a PPS matrix to form a microstructure morphology with the PPS matrix as a continuous phase and elastomer particles as a disperse phase.

EBA, namely ethylene butyl acrylate, has impact resistance at 40 ℃ below zero, is flexible and can be used as a toughening agent; meanwhile, the EBA has high polarity and good compatibility with various polymers. In some embodiments of the present application, the branched polyethylene is typically, but not limited to, EMA (ethylene-methyl acrylate copolymer), EAA (ethylene-acrylic acid copolymer), and EEA (ethylene-ethyl acrylate copolymer).

In modified PPS, polar graft copolymers are used as compatibilizers, including POE-g-GMA (glycidyl methacrylate grafted polyolefin elastomer) and/or SEBS-g-MA (maleic anhydride grafted hydrogenated styrene-butadiene block copolymer).

Optionally, PPS, branched polyethylene, polar graft copolymer, and lubricants;

wherein the branched polyethylene is EBA.

In some preferred embodiments of the application, the toughening agent is preferably EBA. The EBA modified PPS toughening principle is that EBA particles serving as a disperse phase can trigger a PPS matrix to generate a large number of silver grains and shearing bands under the action of external force, so that impact energy is consumed; on the other hand, the larger-sized particles can control the expansion of silver grains, and even the generated shearing bands can stop silver grains and prevent the silver grains from further developing into cracks. Macroscopic appearance is that the impact strength of the material is obviously improved.

Different types of elastomers have different structures and physical properties, and thus have different wettability to the matrix resin, and thus have different toughness improvement to PPS. The EBA has the following advantages for improving the toughness of the PPS:

(1) The EBA has good high temperature resistance. The thermal decomposition temperature of EBA is 330 ℃, and the extrusion processing temperature can be as high as 300 ℃; and the melting point and the softening point are high, and the processing temperature range is wide. And the PPS self-melting point is 281.6-293.7 ℃, and the heating temperature is 290-320 ℃ in the processing procedures of ferrite/modified PPS plastic-magnetic material extrusion granulation, injection molding and the like. The processing and preparing temperatures of the EBA and the ferrite/modified PPS plastic-magnetic material are very compatible, and the product performance is not reduced due to thermal decomposition, but the impact toughness of the composite material can be greatly improved due to the addition of the EBA.

(2) The EBA has better compatibility and inclusion capacity. The EBA has high polarity, good compatibility, high filling force and high environmental stress resistance.

(3) The EBA has good molding performance. Because the molecular weight distribution of EBA is very wide, the melt strength is high, the surface of the extruded and granulated ferrite/modified PPS plastic-magnetic particle is smooth, and the glossiness is high.

(4) The EBA end product has excellent performance. The EBA melting point and softening point are high, and the ferrite/modified PPS plastic-magnetic finished product has good temperature resistance. The EBA modulus is low, and the impact resistance and the flexibility of the ferrite/modified PPS plastic-magnetic material finished product are better.

The polar graft copolymer is POE-g-GMA.

In some preferred embodiments of the present application, the polar graft copolymer is POE-g-GMA, which improves material strength and toughness over SEBS-g-MA.

The compatibility of the components of the blending system is the key of polymer blending modification. Magnetic powder and PPS are two materials with distinct properties. The magnetic powder is a hydrophilic and oleophobic inorganic compound, while the PPS is a lipophilic and hydrophobic organic compound, has amide groups with strong polarity, and has poor two-phase compatibility and serious phase separation phenomenon when being blended with nonpolar magnetic powder or a polymer with weak polarity, thereby causing the decrease of the impact strength of the blend. Therefore, the compatibility of PPS, magnetic powder and other polymers is improved by adding POE-g-GMA, including improving the compatibility, promoting the dispersion of a disperse phase and improving interface bonding.

In order to improve the compatibility of magnetic powder (hydrophilic oleophobic inorganic substance) and high molecular polymers (lipophilic hydrophobic organic substance) such as PPS, POE-g-GMA, PPS, EBA and the like are mixed and melted, so that the prepared graft copolymer has anhydride functional groups, and the anhydride functional groups of the graft copolymer can easily react with terminal amino groups of the PPS to form chemical bonds. The formation of chemical bond at interface effectively reduces the interface energy between magnetic powder and two phases such as PPS, EBA, etc., prevents the disperse phase from agglomerating, promotes the phase dispersion, strengthens the adhesion between the two phases, reduces the particle size of the disperse phase in the system, ensures uniform dispersion and improves the compatibility so as to obtain good interface.

Meanwhile, the compatilizer is beneficial to improving the impact toughness, the compatilizer is added in a formula system of the ferrite/modified PPS plastic magnetic material, the compatibility problem of the compatilizer with magnetic powder, a PPS matrix and EBA is primarily considered, and simultaneously, the cross-linking reaction can be accompanied in the reaction process, the cross-linking degree can influence the performance of a polymer to different degrees, and the aspects of the impact toughness, the fluidity, the apparent performance of the material and the like are mainly shown.

After the compatilizer is added into the modified PPS, the compatilizer is added into the ferrite/modified PPS plastic-magnetic material, so that the interaction force between macromolecules can be weakened, the breaking strength of the material can be reduced, the reduction value of the strength is in direct proportion to the added dosage, and meanwhile, the yield strength of the material can be reduced, and the impact toughness of the material is improved. Meanwhile, the larger the molecular weight of the ferrite/modified PPS plastic-magnetic material is, the larger the acting force and entanglement degree between macromolecular chains are, and the stress cracking resistance of the product is stronger; the broader the molecular weight distribution, the greater the low molecular weight polymer content therein, which is prone to micro-tearing, stress concentrations occur and the article is cracked. In a preferred embodiment of the application, POE-g-GMA is used as the compatilizer, so that the compatilizer has better compatibility with PPS and higher impact toughness.

The lubricant is stearic acid amide.

In a preferred embodiment of the application, the lubricant is stearic acid amide which has excellent lubricating effect and stripping property and is suitable for internal and external lubricants of ferrite/modified PPS plastic-magnetic materials. Stearic acid amide is superior to erucic acid amide and oleic acid amide in lubricating performance, and meanwhile, the stearic acid amide has good affinity with magnetic powder (nonpolar inorganic matters) and PPS (polar organic matters), and can play a role in infiltration. In addition, the processing temperature of PPS enables stearic acid amide to have higher heat stability in terms of high temperature resistance, friction force and adhesive force between a polymer and the surface of equipment can be reduced, and compared with other conventional lubricants, the PPS plastic-magnetic material is more suitable to be used as a lubricant of a ferrite/modified PPS plastic-magnetic material formula system.

In some embodiments of the present application, the parts by weight of PPS in the modified PPS are typically, but not limited to, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, or 90 parts, preferably 85 parts, 86 parts, or 87 parts, more preferably 86 parts; the parts by weight of branched polyethylene are typically, but not limited to, 5, 6, 7, 8, 9 or 10 parts, preferably 6, 7 or 8 parts, more preferably 7 parts; the weight parts of the polar graft copolymer are typically, but not limited to, 3, 4, 5, 6, 7 or 8 parts, preferably 3, 4 or 5 parts, more preferably 4 parts; the parts by weight of the lubricant are typically, but not limited to, 2 parts, 3 parts, 4 parts, 5 parts or 6 parts, preferably 2 parts, 3 parts or 4 parts, more preferably 3 parts.

Optionally, the temperature of the extrusion granulation is 290 ℃ to 320 ℃. In some embodiments of the application, the temperature of extrusion granulation is typically, but not limited to, 290 ℃, 295 ℃, 300 ℃, 305 ℃, 310 ℃, 315 ℃, or 320 ℃.

Preferably, the extrusion granulation time is 5min-15min. In some embodiments of the application, the time of extrusion granulation is typically, but not limited to, 5min, 7min, 9min, 11min, 13min, or 15min.

Optionally, in the double-screw extruder, the temperature of the feed inlet is 275-285 ℃. Preferably, the outlet temperature is 300-315 ℃.

Preferably, the twin screw extruder comprises 5 temperature zones, each temperature zone having a temperature of 275 ℃ to 285 ℃, 300 ℃ to 330 ℃, 310 ℃ to 340 ℃, 300 ℃ to 320 ℃ and 290 ℃ to 310 ℃.

Optionally, the particle size of the modified PPS is 1mm to 5mm. In some embodiments of the application, the particle size of the modified PPS is typically, but not limited to, 1mm, 2mm, 3mm, 4mm, or 5mm.

The ferrite/modified PPS plastic-magnetic material provided by the application has the advantages that the magnetic powder content is increased to 85-88 wt%, the impact toughness is increased by 30%, and the magnetic powder content reaches 8.8kJ/m ² The method comprises the steps of carrying out a first treatment on the surface of the Meanwhile, the melt flow rate of the ferrite/modified PPS plastic magnetic material is improved by 20 percent, which reaches 224g/10min, and the mechanical property and the yield of the ferrite/modified PPS plastic magnetic material are improved. The magnetic property and mechanical property (impact toughness and tensile strength) of the ferrite/modified PPS plastic-magnetic material reach the standard TP-S78 of the household field, and the ferrite/PPS plastic-magnetic material is the highest level of the property of the ferrite/PPS plastic-magnetic material produced in batch at present.

In some embodiments of the present application, the mass percent of the coupling agent surface modified ferrite magnetic powder in the ferrite/modified PPS plastic magnetic material is typically, but not limited to, 85wt.%, 86wt.%, 87wt.%, or 88wt.%; the mass percent of antioxidant is typically, but not limited to, 0.068wt.%, 0.069wt.%, or 0.070wt.%; the mass percent of the modified PPS is typically, but not limited to, 11.96wt.%, 12.96wt.%, 13.96wt.%, or 14.96wt.%.

Some embodiments of the present application will be described in detail below with reference to examples. The following embodiments and features of the embodiments may be combined with each other without conflict. The raw materials used in the present application are commercially available unless otherwise specified.

The PPS used in the following examples and comparative examples was PPS, trade name HB, available from Sichuan Tech Co., ltd, and the performance parameters were as shown in the following table:

example 1

This example provides a modified PPS, which comprises 86kg of PPS, 7kg of EBA, 4kg of POE-g-GMA and 3kg of stearic acid amide.

Mixing the raw materials in a high-speed mixer for 5min, uniformly mixing, and extruding and granulating in a double-screw extruder at 315 ℃; the temperature of the feed inlet is 280 ℃, and the temperature of the discharge outlet is 307 ℃; the rotation speed is 35% Max, the pressure is 1.2MPA, and the torque is 42% Max. The extrusion granulation time of the modified PPS is 8min. And discharging from a die opening, cooling by a drag chain, and granulating by a granulator to obtain the modified PPS with the particle size of 3 mm.

Example 2

The present example provides a modified PPS, which comprises 90kg of PPS, 10kg of EBA, 8kg of POE-g-GMA and 6kg of stearic acid amide.

The preparation method is the same as in example 1.

Example 3

The embodiment provides a modified PPS, which comprises 80kg of PPS, 5kg of EBA, 3kg of POE-g-GMA and 2kg of stearic acid amide.

The preparation method is the same as in example 1.

Example 4

This example provides a modified PPS, which comprises 85kg of PPS, 6kg of EBA, 3kg of POE-g-GMA and 3kg of stearic acid amide.

The preparation method is the same as in example 1.

Example 5

This example provides a modified PPS, which comprises 87kg of PPS, 8kg of EBA, 5kg of POE-g-GMA and 3kg of stearic acid amide.

The preparation method is the same as in example 1.

Example 6

This example provides a modified PPS, which comprises 60kg of PPS, 3kg of EBA, 4kg of POE-g-GMA and 1kg of stearic acid amide.

The preparation method is the same as in example 1.

Example 7

This example provides a modified PPS, except that EMA is used instead of EBA, and the remaining materials and methods are the same as in example 1.

Example 8

This example provides a modified PPS, except that EAA is used instead of EBA, and the remainder of the raw materials and process are the same as in example 1.

Example 9

This example provides a modified PPS, which differs from example 1 in that SEBS-g-MA was used instead of POE-g-GMA, and the remaining materials and methods were the same as in example 1.

Example 10

This example provides a modified PPS, except that erucamide is used instead of stearamide, and the remaining materials and processes are the same as in example 1.

Comparative example 1

This comparative example provides a PPS, which is the same batch product as PPS in examples 1-10.

Test example 1

The modified PPS obtained in examples 1 to 10 and PPS provided in comparative example 1 were subjected to performance tests including melt flow rate, impact strength (notched) and tensile strength of the simple beams, and the data obtained are shown in table 1 below.

TABLE 1

As can be seen from Table 1, the modified PPS of example 1 provided by the present application, using branched polyethylene, improved PPS impact toughness and 41% improvement in impact strength (notched) of a simply supported beam up to 7.6kJ/m ² The method comprises the steps of carrying out a first treatment on the surface of the Meanwhile, the polar graft copolymer is added, so that the polarity of PPS can be enhanced, the PPS can be better mutually fused with a polar or nonpolar system, and the tensile strength is improved by 20% to 186MPA; the addition of the lubricant improves the flow property of PPS, the melt flow rate is improved by 19 percent, and 1307g/10min is reached, thereby solving the defects of unsatisfactory injection molding and uneven injection molding of products caused by poor PPS fluidity. In general, the modified PPS provided by the present application is significantly stronger in melt flow rate, impact strength and tensile strength than the unmodified PPS of comparative example 1.

Example 11

The embodiment provides a ferrite/modified PPS plastic magnetic material, which is prepared by the following steps:

1. 10kg of alcohol and 10kg of Si-900 coupling agent were mixed uniformly. 1000kg of ferrite magnetic powder is poured into a high-speed mixer, the mixture of alcohol and coupling agent is added, and the mixture is stirred for 3 minutes by the high-speed mixer and discharged. And (3) discharging, putting into a baking oven, baking at 90 ℃ for 2 hours, and volatilizing all the alcohol to obtain the ferrite magnetic powder with the surface modified by the coupling agent.

2. 500kg of coupling agent surface modified ferrite magnetic powder, 88kg of modified PPS obtained in example 1, 0.2kg of antioxidant 168 and 0.2kg of antioxidant 1098 are added into a high-speed mixer to be uniformly mixed, and the mixture is stirred by the high-speed mixer for 3 minutes and discharged, so as to obtain mixed magnetic powder. And extruding and mixing the mixed magnetic powder by a double-screw extruder, controlling the extrusion temperature to be 305 ℃, cooling after extrusion, and obtaining ferrite/modified PPS injection molding granules by using a granulator.

3. And (3) performing injection molding on the ferrite/modified PPS injection molding granules on an injection molding machine with a magnetic field orientation device die, wherein the injection molding temperature is controlled to be 315 ℃, the injection molding pressure is 55%, the injection molding speed is 60%, and the orientation current is 40A, so that the ferrite/modified PPS plastic-magnetic material with the diameter of 50mm multiplied by 40mm is obtained.

Example 12

The present example provided a ferrite/modified PPS plastic magnetic material, unlike example 11, in which the modified PPS obtained in example 1 was added in an amount of 68kg, and the remaining raw materials and steps were the same as in example 11, and are not described here again.

Comparative example 2

This comparative example provides a ferrite/PPS plastic magnetic material, unlike example 11, in which the modified PPS was replaced with PPS80 kg, PP (polypropylene) 6kg, and EBS (ethylene bis stearamide) 2kg of comparative example 1, and the remaining materials and steps are the same as example 11, and are not described here.

Comparative example 3

This comparative example provides a ferrite/PPS plastic magnetic material, unlike example 11, in which the modified PPS was replaced with 62kg PPS, 4.5kg PP, and 1.5kg ebs of comparative example 1, and the remaining materials and steps are the same as example 11, and are not described here.

Test example 2

The plastic magnetic materials provided in examples 11-12 and comparative examples 2-3 were subjected to performance tests including melt flow rate MFR, magnetic properties and mechanical properties tests. Wherein the magnetic powder content in example 11 and comparative example 2 was 85wt.%, and the magnetic powder content in example 12 and comparative example 3 was 88wt.%.

Wherein the magnetic performance test is in accordance with GB/T3217 and the test item comprises remanence B _r Coercive force H _cb Intrinsic coercivity H _cj Sum magnetic energy product (BH) _max The method comprises the steps of carrying out a first treatment on the surface of the The mechanical property test comprises an impact strength test and a tensile strength test.

The magnetic properties of the injection molded magnet were measured using a DMT-1 magnetometer of the national academy of metrology. Using a XWW-20KN electronic universal tester from Dewar tester Co., ltd., detecting the cantilever impact strength (notched) of the injection molded magnet according to ASTM-D256, and detecting the tensile strength of the injection molded magnet according to ASTM-D638; the melt index MFR of the injection molded pellets at a temperature of 300℃under a load of 10kg was measured by using a melt index apparatus of the F-F01 type manufactured by Toyo Seiki, which was carried out in accordance with ASTM D1238-98.

The data obtained are shown in table 2 below.

TABLE 2

As can be seen from Table 2, when the magnetic powder contents were 85wt.%, the MFR, the Izod impact strength, and the MFR of comparative example 2 were greatly different from those of Japanese Kochia scop TP-S73 in comparison with the comparative example 11, comparative example 2, and Japanese Kochia scop TP-S73, which are the sources of the material problems of the prior art PPS plastic-magnetic material, and the magnetic performance indexes (including B _r 、H _cb 、H _cj Sum (BH) _max ) There is also a gap from the tensile strength. The modified PPS provided by the application is greatly stronger in impact strength and tensile strength than unmodified PPS, so that the impact strength and tensile strength of a plastic magnetic material product prepared by taking the modified PPS as a raw material are also greatly improved; in addition, the improvement of the modified PPS on the melt rate leads the MFR of the embodiment 11 to be obviously improved, which is beneficial to the magnetic field orientation of the plastic magnetic material in the molten state in the production and preparation process and improves the magnetic performance index. Overall, the technical index of example 11 reached the japanese TP-S73 level.

The magnetic powder content of example 12 was increased from 85wt.% to 88wt.% compared to example 11 and comparative example 3 and comparative example 2 without changing the PPS formulation, and thus the magnetic performance index of example 12 and comparative example 3 was increased. However, the MFR, impact strength and tensile strength of example 12 and comparative example 3 were all reduced due to the reduced proportion of PPS binder.

Comparing example 12, comparative example 3 and Japanese Kochia TP-S78 together at a magnetic powder content of 88wt.% both, the MFR and impact strength of comparative example 3 are already very low, and in this case the injection molded product is extremely susceptible to defects such as cracking and molding difficulties, which seriously affect the yield; the magnetic property index and the tensile strength are also lower than those of Japanese Kochia scop TP-S78. Example 12 Using the modified PPS provided by the present application, impact strength and tensile strength were greatly improved, and MFR and magnetic properties were also achieved to the Japanese TP-S78 level.

Under the two conditions that the magnetic powder content is 85% and 88%, respectively, the technical indexes of the prepared plastic magnetic material are greatly improved by using the modified PPS provided by the application, and the technical level of Japanese Korea is reached, and the key effects of the modified PPS and the application of the modified PPS on ferrite/PPS plastic magnetic materials are proved.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims

1. The modified PPS is characterized by comprising 80-90 parts of PPS, 5-10 parts of branched polyethylene, 3-8 parts of polar graft copolymer and 2-6 parts of lubricant in parts by weight;

the polar graft copolymer comprises POE-g-GMA and/or SEBS-g-MA;

2. The modified PPS of claim 1, including PPS, branched polyethylene, polar graft copolymer, and lubricant;

wherein the branched polyethylene is EBA;

the polar graft copolymer is POE-g-GMA;

the lubricant is stearic acid amide.

3. The modified PPS according to claim 1, including, in parts by weight, 85 to 87 parts of polyphenylene sulfide, 6 to 8 parts of branched polyethylene, 3 to 5 parts of polar graft copolymer, and 2 to 4 parts of lubricant.

4. The modified PPS according to claim 1, including, in parts by weight, PPS86 parts, branched polyethylene 7 parts, polar graft copolymer 4 parts, and lubricant 3 parts.

5. The method for producing a modified PPS according to any one of claims 1 to 4, wherein the modified polyphenylene sulfide is obtained by uniformly mixing the raw materials, extruding and granulating the mixture in a twin-screw extruder, and pelletizing the mixture.

6. The method of claim 5, wherein the extrusion granulation temperature is 290 ℃ to 320 ℃;

the extrusion granulating time is 5min-15min.

7. The method according to claim 6, wherein in the twin-screw extruder, the temperature of the feed inlet is 275 ℃ to 285 ℃;

the temperature of the discharge hole is 300-315 ℃.

8. The method according to claim 5, wherein the twin-screw extruder has a rotational speed of 20% -50% of the maximum rotational speed, a pressure of 0.4MPa-2.0MPa, and a torque of 20% -70% of the maximum torque.

9. The process according to claim 5, wherein the modified PPS has a particle size of 1mm to 5mm.

10. Use of the modified PPS according to any of claims 1-4 in ferrite/PPS plastic magnetic material.

11. The ferrite/modified PPS plastic-magnetic material is characterized by comprising the following components in percentage by mass: the coupling agent surface modified ferrite magnetic powder of 85wt.% to 88wt.%, the antioxidant of 0.068wt.% to 0.070wt.%, and the modified pps11.96wt.% to 14.96wt.% of any one of claims 1 to 4.