CN120818172A

CN120818172A - A method for preparing memory rubber-plastic material with high mechanical properties

Info

Publication number: CN120818172A
Application number: CN202511323093.6A
Authority: CN
Inventors: 姚刚; 邢闯; 杨从兵; 胡飞
Original assignee: Jiangsu Runtaiyin Technology Co ltd
Current assignee: Jiangsu Runtaiyin Technology Co ltd
Priority date: 2025-09-16
Filing date: 2025-09-16
Publication date: 2025-10-21

Abstract

The present invention relates to the technical field of organic polymer material preparation, and discloses a preparation method of a memory rubber and plastic material with high mechanical properties, the method comprising: mixing SBS, TPU, MA-g-PO, hindered phenol and UV absorber raw materials to obtain a premix, melt-plasticizing the premix by a twin-screw extruder to obtain a melt, underwater pelletizing, dehydrating and drying the melt to obtain a rubber and plastic masterbatch, blending the rubber and plastic masterbatch with a compounding agent raw material to obtain a composite material, pressing the composite material by a compression molding machine to obtain a preform, foaming by a foaming furnace to obtain a foamed memory rubber and plastic body, hot pressing and cold pressing the foamed memory rubber and plastic body to shape, and finally annealing the shaped material by a vacuum oven to obtain a memory rubber and plastic material. The final product of the present invention has the characteristics of light weight, high strength, weather resistance, low deformation and rapid complete recovery, and the process does not require supercritical equipment, and is suitable for the fields of aerospace, rail transportation and high-end sports protection.

Description

Preparation method of memory rubber-plastic material with high mechanical property

Technical Field

The invention relates to the technical field of preparation of organic polymer materials, in particular to a preparation method of a memory rubber-plastic material with high mechanical properties.

Background

In the prior art, most of memory rubber-plastic materials take TPU, EVA or SBS as a single matrix, and it is often difficult to consider low density, high rebound, low compression set and high deformation recovery rate, and the triangle contradiction of elastic-set-recovery rate has become a core bottleneck for restricting the application in fields of high-end sport protection, aerospace buffering, automobile safety seats and the like.

The adaptability of the traditional memory rubber and plastic formula to the outdoor environment is generally insufficient, in the prior art, hindered phenol antioxidants or benzotriazole ultraviolet absorbers are simply added into a matrix, and due to the lack of cooperative design, materials are rapidly degraded under the coupling action of multiple aging factors such as ultraviolet light, thermal oxygen, ozone and the like, the weather-resistant short plate enables the memory rubber and plastic products to be incapable of passing service life assessment in application scenes requiring maintenance free for more than 5 years, and the high-end and internationalization process of the products is severely limited.

At present, a three-stage rough mixing-molding-foaming process is commonly adopted in the industry, the mixing stage depends on manual feeding of an open mill or an internal mixer, in addition, the process data mainly comprise paper records, and the high-dispersion and low-traceability production mode not only causes rework of a large number of wastes, but also enables enterprises to be unable to pass through high-end quality system authentication, and becomes a main obstacle for restricting products from entering an automobile or an aviation supply chain.

To obtain a uniform cellular structure, some high-end manufacturers employ supercriticalOr the high-pressure nitrogen physical foaming technology has high equipment maintenance and energy consumption costs, and is prohibitive for small and medium enterprises due to high capital expenditure and technical barriers, and the market is in a malformation pattern of 'high-end dependence import and low-end low-price competition', so that the industry is in need of a low-cost technical route which can be implemented on the existing general rubber and plastic equipment and has excellent performance so as to break the technical monopoly and realize the large-scale production of the high-performance memory rubber and plastic material.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a preparation method of a memory rubber plastic material with high mechanical property.

In order to achieve the aim, the invention adopts the following technical scheme that the preparation method of the memory rubber plastic material with high mechanical property comprises the following steps:

Step S1, measuring raw materials, wherein each 55-115 phr of raw materials comprise 30-50 phr of SBS, 20-40 phr of TPU, 5-15 phr of MA-g-PO, 0.5-3 phr of hindered phenol and 0.1-1 phr of UV absorber, and putting the raw materials into a high-speed mixer for blending to obtain uniform premix;

s2, carrying out melting plasticization on the uniform premix by a double-screw extruder to obtain a melt;

s3, underwater granulating, dehydrating and drying the melt to obtain rubber and plastic master batches;

S4, taking a complexing agent raw material, and putting the rubber and plastic master batch and the complexing agent raw material into a high-speed mixer for blending to obtain a composite material, wherein the complexing agent raw material comprises 5-15 phr of nanometer particles treated by a silane coupling agent, 1-5 phr of boron nitride nanometer sheets, 0.5-2 phr of an organic peroxide cross-linking agent and 1-3 phr of foaming agent AC;

step S5, pressing the composite material by a compression molding machine to obtain a preform;

s6, foaming the preform through a foaming furnace to obtain a foaming memory rubber body;

S7, performing hot press shaping and cold press shaping on the foaming memory rubber body to obtain a shaped material;

and S8, annealing the shaped material through a vacuum oven to obtain the memory rubber plastic material.

The technical scheme provided by the invention has the beneficial effects that at least:

According to the invention, through SBS+TPU bicontinuous phase structural design, MA-g-PO is introduced as an interface compatibilizer, so that polar TPU and nonpolar SBS form a nanoscale interpenetrating network in a molten state, meanwhile, a two-dimensional heat conduction/enhancement framework is constructed in a matrix through a boron nitride nanosheet, and controllable crosslinking is completed in a 180 ℃ die pressing window by matching with an organic peroxide crosslinking agent, so that the synergistic breakthrough of high strength, high elasticity and low deformation under a low density condition is realized.

The invention constructs an MFR-moisture-density-recovery rate four-stage closed-loop quality control system, all data are automatically recorded by a PLC and CSV trace files are generated, the batch numbers are in one-to-one correspondence with the production time, the equipment parameters and the raw material batches, the material yield is effectively improved, the requirements of a high-end quality system are met, and technical support is provided for enterprises to enter an automobile or aviation supply chain.

The technical route of the invention can be realized on general rubber and plastic equipment without expensive devices such as an autoclave, a supercritical fluid generator and the like, and the SBS, TPU, MA-g-PO, the hindered phenol and the boron nitride nanosheets are all realized domestically in terms of raw materials, so that the raw material cost and the process energy consumption are reduced, the comprehensive cost of the product can be controlled to 60-70% of that of imported like products, a high-cost performance scheme capable of being rapidly copied is provided for small and medium enterprises, and the invention is hopeful to promote the comprehensive popularization of high-performance memory rubber and plastic materials in civil or industrial fields.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions and advantages of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are only some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1 is a flowchart of a method according to an embodiment of the present invention.

Detailed Description

In order to further illustrate the technical means and effects adopted by the invention to achieve the preset aim, the following is a detailed description of specific implementation, structure, characteristics and effects of a preparation method of a memory rubber plastic material with high mechanical properties according to the invention, which is provided by the invention, with reference to the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" means that the embodiments are not necessarily the same. Furthermore, the particular features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

The specific scheme of the preparation method of the memory rubber-plastic material with high mechanical property provided by the invention is specifically described below with reference to the accompanying drawings.

Referring to fig. 1, a method flowchart of a method for preparing a memory rubber-plastic material with high mechanical properties according to an embodiment of the invention is shown, and the method includes the following steps:

S1, raw materials are measured, and are put into a high-speed mixer to be blended, so that uniform premix is obtained;

Wherein in step S1, the method further comprises the following sub-steps:

S1-1, measuring raw materials by an electronic scale, wherein each 55-115 phr of raw materials comprises 30-50 phr of SBS, 20-40 phr of TPU, 5-15 phr of MA-g-PO, 0.5-3 phr of hindered phenol and 0.1-1 phr of UV absorber;

S1-2, drying the SBS and the TPU through an oven, wherein the drying temperature is 60 ℃ and the duration time is 2 hours, and manually premixing the hindered phenol and the UV absorber for 30 seconds;

S1-3, setting the jacket temperature of the high-speed mixer to be 70 ℃, heating at a temperature rise rate of 5 ℃ per minute, enabling the high-speed mixer to run for 3 minutes in a no-load mode, and after a temperature control meter red lamp of the high-speed mixer is observed to be normally on, sequentially adding raw materials within 30 seconds, wherein the sequence is that firstly, dried SBS and TPU are added, secondly, MA-g-PO is added, and finally premixed hindered phenol and UV absorbent are added;

s1-4, carrying out three-stage mixing on the input raw materials by a high-speed mixer, wherein the three-stage mixing comprises the following steps:

stage one, wherein the temperature is 60 ℃, the rotating speed is 400rpm, and the duration is 1min;

Stage two, wherein the temperature is 70 ℃ and the rotating speed is 1000rpm, and the duration is 3min;

Step three, the temperature is 75 ℃, the rotating speed is 800rpm for 4min, then the heating is closed, the side wall cooling water valve of the high-speed mixer is opened, cooling water is introduced, the rotating speed is 300rpm, the duration is 2min, and a uniform premix is output;

S1-5, sampling 50g of the uniform premix, and performing an MFR test of 190 ℃ and 2.16kg, if the MFR value deviates from the target value And (5%) judging the uniform premix as a qualified product, filling the qualified product into a vacuum bag, sealing and labeling, marking the premix-batch number-time, transferring the qualified product into a double-screw extruder within 4 hours, and scrapping the unqualified product.

The SBS (Styrene-Butadiene-Styrene block copolymer) is provided in a white or light yellow porous particle form, and key indexes comprise Styrene/Butadiene mass ratio of 30/70, MI (190 ℃ C., 5 kg) of 5-15 g/10min and Shore A hardness of 70+/-3, and the SBS is used for providing an elastic framework and a rubber phase for a material and determining high rebound and shape memory performance of the material.

TPU (Thermoplastic Polyurethane ) is provided in the form of transparent or yellowish cylindrical particles, and key indexes comprise 80-95 Shore A, tensile strength of more than or equal to 30MPa, elongation at break of more than or equal to 500%, and the TPU is used for improving tensile/tearing strength and simultaneously endowing the material with excellent low-temperature flexibility and oil resistance.

MA-g-PO (MALEIC ANHYDRIDE GRAFTED Polyolefin ) is supplied in the form of white particles, and key indexes comprise grafting rate of 0.8-1.2wt%, melting index (190 ℃ C., 2.16 kg) of 1-5 g/10min, and the grafting rate is used for improving interface cohesive force of materials through reaction of anhydride groups with polar chain segments of TPU and SBS, so that mechanical properties of the materials are improved.

The hindered phenol (Hindered Phenolic Antioxidant) is white crystal powder, and the key indexes include melting point of 110-125 ℃ and the key indexes are as follows, wherein the hindered phenol is used for capturing free radicals, inhibiting thermal oxygen degradation and ensuring the thermal stability of the material in the subsequent extrusion and foaming processes.

The UV absorber (Ultraviolet Absorber) is light yellow powder or microbeads, and has the key indexes of absorption peak of 290-360nm, thermal decomposition temperature of more than or equal to 250 ℃ and the key indexes of absorbing ultraviolet light and converting the ultraviolet light into harmless heat energy, so as to prevent outdoor yellowing and mechanical property reduction of material products.

The specification of the blast oven is that the effective volume is more than or equal to 100L, the air quantity is adjustable, and the temperature control precision is +/-2 ℃.

The manual premixing tool comprises a 250mL stainless steel cup and a glass rod, and the specific operation comprises the steps of adding hindered phenol and a UV absorbent into the cup according to a formula at one time, stirring the mixture clockwise for 30 seconds by the glass rod, and visually observing that no obvious color spots exist, so that dust flying during subsequent high-speed mixing is reduced, and the dispersion uniformity of a small-dose auxiliary agent is improved.

The high-speed mixer has the specification of 10L vertical type, the variable frequency speed regulation range of 300-1500 rpm and supports the circulating heating and cooling of a jacket, and key components comprise a double-layer four-way baffling blade, a side wall cooling water coil pipe and a PID regulating temperature control meter.

Instrument and conditions for MFR test:

The equipment comprises a melt flow rate instrument with temperature control precision of +/-0.5 ℃, a die material, tungsten carbide, an inner diameter of 2.095mm +/-0.005 mm and a length of 8.000mm +/-0.025 mm;

Operational flow example:

Preheating, namely loading a weight of 2.16kg after the temperature of 190 ℃ in a charging barrel is kept constant for 5 min;

Sampling, namely discarding the effluent of the first 2min after the start of the instrument, then intercepting the effluent of 5 continuous 1min sections for MFR value detection, and taking the average value of the detection results as a final MFR value;

Setting the MFR target value of the premix to be 8.0g/10min, and setting the qualification interval to be 8.0g/10min x (1+/-5%) =7.6-8.4 g/10min;

And (3) out-of-tolerance treatment:

If the MFR value is less than 7.6g/10min, the ingredients are scrapped and checked possibly because the SBS/TPU ratio is high or the auxiliary agent is not dispersed;

If the MFR value is >8.4g/10min, the TPU is possibly excessive or the moisture is high, and the TPU is also scrapped, so that insufficient torque of the extruder or foam collapse is prevented.

wherein in step S2, the method further comprises the following sub-steps:

S2-1, sequentially setting barrel temperatures of barrel 1 region to barrel 10 region of the double-screw extruder to be 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 215 ℃, 210 ℃, 205 ℃ and 200 ℃, setting screw preheating oil temperature of the double-screw extruder to be 80 ℃ and preheating duration to be 30min, and setting vacuum degree of a vacuum pumping system of the double-screw extruder -0.08MPa, and setting the initial screw speed of the twin-screw extruder to 50rpm, and increasing the screw speed to 200-300 rpm after the torque is stable;

S2-2, setting the feeding amount of the premix to be 30kg/h, feeding the premix into a machine barrel 1 area according to the feeding amount, starting a double-screw extruder, sequentially carrying out melt plasticization on the premix through the machine barrel 1 area to the machine barrel 10 area, and finally outputting a melt;

s2-3, filtering the output melt by a 80-mesh and 120-mesh double-layer filter screen changer, and setting the filtering pressure of the changer 15MPa, setting a pressure difference alarm value of 20MPa, judging that the melt which is filtered and does not trigger the pressure difference alarm is qualified, and pumping the qualified product to a granulator.

The specification of the twin-screw extruder is that the twin-screw extruder is a parallel twin-screw extruder meshed in the same direction, the L/D=40:1, and the screw diameter is 52mm;

The screw is partitioned into 10 independent temperature control areas (1-10 areas), each area is provided with a cast aluminum heater and a water cooling jacket, and the screw comprises:

A conveying section (1-2 zone) of a large-lead forward thread element;

the melting/plasticizing section (3-5 zone) is composed of 60-degree kneading blocks and reverse thread elements, so that shearing and dispersion are improved;

mixing/devolatilizing sections (6-7) are 90 DEG kneading blocks and toothed discs, and homogenization is enhanced;

And the pressure-building conveying section (8-10 areas) is used for building melt pressure by using a small-lead forward threaded element.

Composition of the evacuation system:

the position is that a round hole with the diameter of 30mm is formed above the cylinder body in the 7 th zone and is provided with a double-screw lateral exhaust screw;

The vacuum pump is a rotary vane type oil seal vacuum pump, the rated pumping speed is 63m < 3 >/h, and the ultimate vacuum degree is less than or equal to-0.09 MPa;

and a vacuum pipeline, namely a stainless steel corrugated pipe and a condensation trap (ice saline water at 0-5 ℃) are used for capturing low-molecular volatile matters, so that oil pumping emulsification is prevented.

The judgment mode of the torque stability is that the torque of the main motor of the extruder is output in real time (0-10V or 4-20 mA signal) and is automatically judged by combining with a PLC embedded judgment algorithm.

Specification of screen changer:

Example types are double-station slide-plate hydraulic screen changer, screen combination as follows:

A first layer of filter screen, namely an 80-mesh stainless steel woven net (with the aperture of 180 μm);

The second layer of filter screen is a 120-mesh stainless steel woven net (aperture 125 μm), and a 2mm thick splitter plate is added between the two layers.

wherein in step S3, the method further comprises the following sub-steps:

S3-1, stripping and traction are carried out on the melt through a die head of a granulator to obtain the alloy with the diameter of 3.0 0.2Mm of strip melt, the diameter of a die hole of a die head is 3mm, the traction speed is 15m/min, and the temperature of cooling water is 25 ℃;

S3-2, setting the rotating speed of a granulator to be 1200rpm, setting the water temperature to be 20 ℃ and the water flow rate to be 20L/min, and carrying out underwater granulation on the strip-shaped melt by the granulator to obtain initial master batches with the length of 2-4 mm;

s3-3, setting the rotating speed of a centrifugal machine to be 1000rpm, and carrying out centrifugal dehydration on the initial master batch for 2min to obtain dehydrated master batch;

s3-4, setting the temperature of a hot air circulation oven to be 80 ℃, turning over once every 1h for 4h, heating and drying the dehydrated master batch through the hot air circulation oven, and then stopping heating and naturally cooling to be less than or equal to 35 ℃ to obtain a rubber-plastic master batch;

s3-5, taking 5g of sample from the rubber and plastic master batch, detecting the moisture content of the sample by using a Karl Fischer moisture meter, and if the detection result is the moisture content And (3) 0.05wt% of the rubber and plastic master batch, judging that the sampled rubber and plastic master batch is qualified, filling the qualified rubber and plastic master batch into a vacuum aluminum foil bag, sealing and labeling, marking the rubber and plastic master batch, and returning the unqualified rubber and plastic master batch to a hot air circulation oven for re-drying.

The specification of the granulator is that the horizontal underwater granulator has an underwater cavity volume of 12L and is provided with a hard alloy rotary cutter (the cutter number is 4, the cutter thickness is 3 mm) and a round hole die head (the aperture is 3.0mm multiplied by 24 holes);

the traction system is a three-roller type traction machine, and the traction roller is coated with silicon rubber to prevent adhesion, and has the hardness of 70Shore A;

when in operation, water is firstly introduced, then the cutter is started, and finally melt is introduced, so that the cutter is prevented from being burnt by dry cutting.

The centrifugal machine has the exemplary specifications that a vertical three-leg centrifugal dehydrator is provided with a drum with the diameter of 300mm, the volume of 8L and a lining of an FEP anti-sticking layer with the thickness of 1mm, the FEP anti-sticking layer is driven by a 2.2kW variable frequency motor, the rotating speed is 0-1500rpm, the bottom discharge opening is manually opened and covered and lifted, and the rapid clamping with the diameter of 100mm is provided for rapid discharging.

The hot air circulation oven has the example specifications that the size of a working chamber is 450mm multiplied by 450mm (the effective volume is 90L), and the thickness of a stainless steel liner is 1.2mm;

The heating system is a 2kW stainless steel fin electric heating pipe, and a centrifugal fan is arranged at the top for forced circulation at 1200 rpm;

The temperature control system is a PID controller and a Pt100 sensor, and the precision is +/-1 ℃.

The Calf Fischer moisture meter has the exemplary specification of volume drop shaping, resolution of 0.01mgH ₂ O and repeatability of less than or equal to + -0.5%.

Hydranal Composite 5 (single component, 5mgH ₂ O/mL) as titration solution;

solvent, anhydrous methanol (less than or equal to 0.01% H ₂ O), and 30mL of the solvent are added each time.

S4, taking a complexing agent raw material, and putting the rubber and plastic master batch and the complexing agent raw material into a high-speed mixer for blending to obtain a composite material;

wherein in step S4, the method further comprises the following sub-steps:

S4-1, weighing by an electronic scale to obtain 100phr of rubber and plastic master batch and a complexing agent raw material, wherein the complexing agent raw material comprises 5-15 phr of nano-particles treated by a silane coupling agent Labeling each complexing agent raw material, namely labeling the raw material, namely labeling batches, weighing people and weighing time of the complexing agent raw material, 1-5 phr of boron nitride nano-sheets, 0.5-2 phr of organic peroxide crosslinking agent and 1-3 phr of foaming agent AC;

s4-2, nanometer Adding the mixture with boron nitride nanosheets into a 1L high-speed dispersing cup, mixing for 30s at a speed of 1000rpm to obtain primary mixed powder, spraying an organic peroxide crosslinking agent into the primary mixed powder in a dropwise manner within 30 seconds, and mixing for 60s at a speed of 800rpm to obtain the product+Boron nitride+crosslinker premix powder;

S4-3, adding the foaming agent AC and 1phr rubber and plastic master batch into a 1L high-speed dispersing cup, and mixing for 30S at a rotating speed of 500rpm to obtain AC-master batch pre-coated particles;

S4-4, pumping 25 ℃ circulating water into a jacket of the high-speed mixer and carrying out idle running for 1min, and then feeding in sequence within 30 seconds, wherein the sequence comprises the steps of firstly feeding rubber-plastic master batches, then uniformly scattering SiO ₂ +boron nitride+cross-linking agent premixed powder within 10 seconds, and finally feeding 'AC-master batch precoated' particles;

S4-5, mixing the materials by a high-speed mixer at the rotating speed of 1000rpm for 3min, and if the cavity temperature of the high-speed mixer is more than 40 ℃ in the mixing process, spraying cold air at 25 ℃ by automatic pulse for cooling, and outputting to obtain a composite material;

S4-6, spreading the composite material on a stainless steel tray, and air-cooling to And (3) filling the mixture into a double-layer PE bag at the temperature of 30 ℃, vacuumizing, sealing and labeling, marking a composite batch, and transferring the composite batch into a compression molding machine within 4 hours.

The silane coupling agent treated nano-meterThe supply form is white fluffy powder, the loose density is 0.12-0.15 g/cm3, and the vacuum aluminum foil bag is 1 kg/bag, and is internally filled with nitrogen for protection, and the action mechanism is that the surface double bond can be covalently bonded with the anhydride group of MA-g-PO and the peroxide cross-linking agent, thereby improving the quality of the productAnd the interface strength with SBS/TPU matrix is provided, and meanwhile, the material has high wear resistance and dimensional stability.

The boron nitride nano-sheet is in a supply form without surface modification (electrical insulation and high thermal conductivity are kept), adsorbed water is removed by vacuum drying for 2 hours at the temperature of 120 ℃ before use, and the action mechanism is that a two-dimensional heat conduction/enhancement network is formed in a material matrix, so that the compression rebound and thermal diffusivity of a subsequent foaming body are improved.

The typical variety of the organic peroxide crosslinking agent is dicumyl peroxide (DCP, dicumyl Peroxide) with the purity of more than or equal to 98 percent, the half-life temperature of 1min is 171 ℃, the molding and foaming temperature window of 180-190 ℃ in the process is satisfied, the supply form is white crystal flakes, the melting point is 39-41 ℃, the PE bag is lined by a 2kg aluminum bottle, the normal state is 4 ℃ and the bag is refrigerated in a dark place, and the bag is taken out and returned to the temperature for 30min before use to prevent moisture absorption.

Foaming agent AC (azodicarbonamide ) supplied in the form of yellow micro powder, paper drum lined with double PE bags, air-dried for 2 hours at the first 60 ℃ to remove residual moisture and free amine smell.

High-speed dispersing cup, 1L double-layer stainless steel cup, external jacket can be passed through with 25 deg.C circulating water, bottom turbine rotor and maximum rotating speed of 12000rpm, and said invention uses three gears of 1000/800/500 rpm.

wherein in step S5, the method further comprises the following sub-steps:

S5-1, preheating a die of a die press forming machine, wherein the preheating temperature is 180 ℃ and the duration time is 20min;

S5-2, preheating the composite material through an oven, setting the preheating temperature to be 80 ℃ and the duration to be 10min to obtain the preheated composite material, and according to the die volume of the compression molding machineTaking the preheated composite material 1.05 times, and carrying out feeding and die closing within 30 seconds to obtain a die filled with the composite material;

s5-3, placing a die filled with the composite material into a compression molding machine for four-stage compression molding and shaping, wherein the method comprises the following steps of:

The initial pressure exhaust stage is that the temperature is not raised, the pressure is 5MPa, and the duration is 30s;

High pressure setting stage, temperature 180 DEG C 5 ℃ And pressure of 12MPa, and duration of 6min;

the gradient pressure relief stage is to reduce the pressure by 2-3 MPa every 30s, open the die by 2mm and discharge the air for 30s, and the pressure is reduced to After 8MPa, the process is carried out in the next stage;

And in the cold press shaping stage, 25 ℃ cooling water is introduced, the pressure is 8MPa, the duration is 3min, then the automatic ejection and demoulding are carried out by a compression molding machine, the preform is obtained, the preform is weighed, and the quality and the batch of the preform are recorded.

The molding press has the exemplary specifications that an upper movable four-column hydraulic press with the rated total tonnage of 300t (3000 kN), a workbench surface of 500mm multiplied by 500mm, an electric heating plate and heat conducting oil circulation double system are adopted, 61 kW plug-in electric heating rods are respectively arranged in an upper hot plate and a lower hot plate, and a heat conducting oil channel is matched, so that the temperature difference is less than or equal to +/-2 ℃ at 180 ℃;

temperature control, namely PID temperature control, closed loop feedback of a K-type thermocouple and resolution of 0.1 ℃;

Pressure control, namely a proportional servo hydraulic system, wherein the pressure closed-loop precision is +/-0.2 MPa and can be set within the range of 0-20 MPa;

The maximum mould opening and closing stroke is 400mm, the mould opening and closing stroke is detected in real time by a magnetic grating ruler, and the repeated positioning precision is +/-0.02 mm;

a cooling interface, namely, 25 ℃ cooling water is introduced into the lower hot plate, the flow is 20L/min, and the switching time is less than 10s;

program control:

the process comprises the steps of initial pressure exhaust, high pressure shaping, gradient pressure relief, cold press shaping, and real-time curve recording of time, temperature and pressure parameters through one-key calling of a PLC+touch screen.

And (3) data recording, namely automatically generating a CSV file containing a time stamp, temperature, pressure, position and batch number, and enabling the CSV file to be exported by USB.

wherein in step S6, the method further comprises the following sub-steps:

s6-1, preheating the foaming furnace, wherein the preheating temperature is 190 ℃ and the duration is 30min, and then placing the preformed blanks into a net frame of the foaming furnace within 5min, wherein the spacing between adjacent preformed blanks 15mm;

S6-2, performing three-stage foaming on the preform through a foaming furnace, wherein the three-stage foaming comprises the following steps:

the temperature rise expansion stage is that the furnace temperature is 190 ℃ and the duration time is 10min;

the shaping and shaping stage, wherein the furnace temperature is 190 ℃ and the duration is 2min;

stopping heating, reducing furnace temperature from 190 ℃ to 50 ℃ at a temperature reducing rate of 7 ℃ per minute by a variable frequency control fan, and naturally cooling to the temperature Outputting a foaming memory rubber body at 40 ℃;

S6-3, at 0.25 Performing quality sampling inspection on the foaming memory rubber body by using sampling inspection density of 0.02g/cm < 3 >, and judging that the sampling inspection result is compression set recovery rate95% Of foaming memory rubber bodies are qualified products, and the foaming memory rubber bodies are attached with batch numbers, so that unqualified products are scrapped.

The foaming furnace has the exemplary specifications that a forced hot air circulation box-type furnace has an effective cavity of 600mm multiplied by 900mm, a 12kW stainless steel fin electric heating pipe, PID+SSR temperature control, resolution of 0.1 ℃ and hearth temperature difference of less than or equal to +/-2 ℃;

Hot air circulation, namely a 1.5kW high-temperature resistant centrifugal fan (variable frequency control), wherein the air quantity is 1200m < 3 >/h, and the diagonal arrangement of the air supply/return inlets forms vortex so as to ensure uniform temperature;

The net frame is 304 stainless steel punching net plate, the aperture is 3mm, the aperture ratio is 35%, and the distance between adjacent plate layers is 15mm.

The compression set recovery rate is defined as:

In the formula, To the original thickness of the steel sheet,To be a thickness in a compressed state,Is the thickness after recovery;

according to GB/T7759.1-2015/ISO815-1 standard (equivalent ASTMD 395B), a sample is taken and tested, specifically as follows:

1) Cutting the foaming memory rubber body into a cylinder with the diameter of 29mm and the height of 12.5mm to be used as a sample;

2) The samples were conditioned at 23℃/50% RH for 24h and measured ;

3) The sample was loaded into a compression jig and compressed to 9.38mm by a stainless steel restrictor (i.e) Locking the rear part;

4) Placing into an incubator at 70deg.C for 22h (simulating long-term service), taking out, cooling at room temperature for 30min, and measuring sample ;

5) Unloading the sample, recovering freely for 30min, and measuring the sampleAnd calculating the compression set recovery rate according to a formula.

wherein in step S7, the method further comprises the following sub-steps:

s7-1, preheating a hot pressing plate of a hot press, and setting the preheating temperature to be 80 ℃ and the duration to be 15min;

S7-2, preheating the foaming memory rubber body through an oven, wherein the preheating temperature is 60 ℃, the duration is 5min, and placing the preheated blank into a mirror surface stainless steel die and fixing through a locating pin;

S7-3, performing three-stage hot press shaping on the preheated blank by a hot press, wherein the method comprises the following steps:

the initial pressure laminating stage is that the temperature is not raised, the pressure is 3MPa, and the duration is 30s;

hot pressing shaping stage, wherein the temperature is 80 ℃, the pressure is 10MPa, and the duration is 3min;

step of gradient decompression, namely decompressing 2MPa every 10s, taking out the hot-pressed blank after the pressure is reduced to 2MPa, and then moving the hot-pressed blank and the whole die thereof to a cold press within 30 seconds;

S7-4, pre-cooling a cold pressing plate of the cold press, setting the pre-cooling temperature to be 0 ℃ and the duration time 10min;

S7-5, cold pressing and shaping the hot-pressed blank by a cold press, setting the temperature to be 0 ℃, the pressure to be 5MPa, and the duration to be 2min to obtain a shaped material, and recording the quality, thickness and batch of the shaped material.

The specification of the hot press is that an up-press four-column servo hydraulic hot press is rated with 100t (1000 kN) of tonnage and the working table is 400mm multiplied by 400mm;

the heating system is characterized in that 6 800W plug-in electric heating rods are respectively arranged in an upper hot plate and a lower hot plate, PID temperature control is carried out in a partition mode, the temperature range is between room temperature and 120 ℃, the control precision is +/-1 ℃, and the temperature difference of a plate surface is less than or equal to +/-2 ℃ when the temperature is 80 ℃;

the pressure system is driven by a servo motor, a roller screw and hydraulic pressurization in a combined way, and the pressure closed-loop precision is +/-0.1 MPa, and can be set at will within 0-15 MPa;

The travel and positioning are that the electric servo travel is 200mm, the repeated positioning is +/-0.02 mm, and the magnetic grating ruler feeds back in real time.

The programmable three-stage hot pressing, namely, initial pressing lamination, hot pressing shaping, gradient pressure relief, wherein the time, temperature, pressure and rising/falling slope of each stage can be independently set and recorded;

The cold press has the exemplary specification that a down-pressing four-column hydraulic cold press is provided with a rated tonnage of 60t (600 kN), a working table surface of 400mm multiplied by 400mm and a die interface shared with a hot press;

The cooling system is characterized in that 0 ℃ chilled water (25% glycol) is filled into the upper and lower cold plates, the cooling water flow is 15L/min, the plate surface temperature is 0+/-1 ℃ (Pt 100 closed loop), and the surface temperature difference is less than or equal to +/-1.5 ℃;

the pressure system is a proportional servo hydraulic pressure, the pressure closed-loop precision is +/-0.05 MPa, and the pressure system can be arbitrarily set within 0-10 MPa;

And the stroke and the positioning are 150mm, repeated positioning is carried out by +/-0.02 mm, and the ejection cylinder is integrated on the lower cold plate.

S8, annealing the shaped material through a vacuum oven to obtain a memory rubber plastic material;

Wherein in step S8, the method further comprises the following sub-steps:

s8-1, preheating a vacuum oven at a preheating temperature of 60 ℃ and a vacuum degree -0.09MPa for a duration of 15min;

s8-2, spreading the shaped material in a stainless steel net-shaped disc, placing the stainless steel net-shaped disc filled with the shaped material in a vacuum oven, and spacing between adjacent stainless steel net-shaped discs Vacuum annealing the shaped material by a vacuum oven at 60 ℃ and vacuum degree of-0.09 MPa for 2h with 20 mm;

s8-3, stopping heating the vacuum oven, maintaining the vacuum degree to be-0.09 MPa, and naturally cooling to be At 35 ℃ to obtain the memory rubber-plastic material of 0.25The memory rubber plastic material is subjected to the sampling inspection with the sampling inspection density of 0.02g/cm < 3 >, and if the sampling inspection result is the compression set rate5% Deformation recovery95%, Judging the memory rubber plastic material as a qualified product, filling the qualified product into an aluminum foil bag, vacuumizing, sealing and labeling the aluminum foil bag, marking the aluminum foil bag as a finished memory rubber plastic material product, and scrapping the unqualified product.

The vacuum oven has the exemplary specifications of a vertical cylinder or square box cavity, and the effective size is 400mm multiplied by 450mm, and a 304 stainless steel liner;

The heating system is an external heating sleeve or a radiation plate, the total power is 1.5kW, the PID temperature control is 0-120 ℃, and the resolution is 0.1 ℃;

The vacuum system comprises a rotary vane vacuum pump 2XZ-4, an electromagnetic baffle valve and a vacuum gauge (resistance gauge), wherein the vacuum system is used for displaying in real time and performing closed-loop control, and the precision is-0.09 MPa +/-0.005 MPa;

the safety interlocking system is automatically powered off when the temperature exceeds 70 ℃, and the vacuum degree is minus 0.08MPa for 30 seconds to give an alarm;

the loading mode is that a stainless steel net-shaped tray (punching 3mm, aperture ratio 40%, single-layer bearing less than or equal to2 kg) can be placed with 5 layers at the same time, so that heat radiation and vacuum channels are ensured to be uniform.

The deformation recovery rate is defined as:

In the formula, For maximum compressive strain (set to 70%),In order to unload the residual strain after 30 minutes,To the original thickness of the steel sheet,To be a thickness in a compressed state,Is the thickness after recovery;

According to the GB/T1683-2018 standard and combining with the common practice of the shape memory material industry, taking a sample and detecting, the specific steps are as follows:

1) Cutting the memory rubber plastic material into a cylinder with the diameter of 29mm and the height of 12.5mm to be used as a sample;

2) The sample was conditioned at 23℃for 24h and measured ;

3) The sample was loaded into a compression jig and compressed to 9.38mm by a stainless steel restrictor (i.e) Locking and keeping for 30min;

4) Unloading the sample, recovering freely for 30min, and measuring the sample And calculating the deformation recovery rate according to a formula.

The foregoing embodiments are merely illustrative of the technical solutions of the present application, and not restrictive, and although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that modifications may still be made to the technical solutions described in the foregoing embodiments or equivalent substitutions of some technical features thereof, and that such modifications or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a memory rubber-plastic material with high mechanical properties, characterized in that the method comprises:

Step S1, measuring raw materials, where every 55-115 phr of the raw materials includes 30-50 phr of SBS, 20-40 phr of TPU, 5-15 phr of MA-g-PO, 0.5-3 phr of hindered phenol, and 0.1-1 phr of UV absorber, and putting the raw materials into a high-speed mixer for blending to obtain a uniform premix;

Step S2, melting and plasticizing the uniform premix by a twin-screw extruder to obtain a melt;

Step S3, underwater pelletizing, dehydrating and drying the melt to obtain rubber and plastic masterbatch;

Step S4, measuring a composite material raw material, putting the rubber and plastic masterbatch and the composite material raw material into a high-speed mixer for blending to obtain a composite material, wherein the composite material raw material includes 5-15 phr of nanoparticles treated with a silane coupling agent, 1-5 phr of boron nitride nanosheets, 0.5-2 phr of an organic peroxide crosslinking agent, and 1-3 phr of a foaming agent AC;

Step S6, foaming the preform in a foaming furnace to obtain a foamed memory rubber-plastic body;

Step S7, hot pressing and cold pressing the foamed memory rubber plastic to obtain a shaped material;

Step S8: annealing the shaped material in a vacuum oven to obtain a memory rubber-plastic material.

2. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, step S1 further includes the following sub-steps:

S1-1, measure the raw materials using an electronic scale;

S1-2, drying the SBS and TPU in an oven at a temperature of 60° C. for 2 hours, and manually premixing the hindered phenol and UV absorber for 30 seconds;

S1-3, set the jacket temperature of the high-speed mixer to 70°C and the heating rate to 5°C/min, and run the high-speed mixer at no load for 3 minutes. After observing that the red light on the temperature control meter of the high-speed mixer is always on, add the raw materials in the following order within 30 seconds: first add the dried SBS and TPU, then add the MA-g-PO, and finally add the premixed hindered phenol and UV absorber;

S1-4, performing three-stage mixing of the input raw materials by the high-speed mixer, including:

Stage 1: temperature 60°C, speed 400 rpm, duration 1 min;

Stage 2: temperature 70°C, speed 1000 rpm, duration 3 min;

Stage 3: Temperature 75°C, speed 800 rpm for 4 minutes, then turn off the heating, open the side wall cooling water valve of the high-speed mixer and pass cooling water, speed 300 rpm, duration 2 minutes, output uniform premix;

S1-5, take 50g of the uniform premix sample and perform MFR test at 190℃ and 2.16kg. If the MFR value obtained deviates from the target value, ±5%, the uniform premix is judged to be qualified, and the qualified products are put into vacuum bags, sealed and labeled with "premix-batch number-time", and transferred to the twin-screw extruder within 4 hours, and unqualified products are scrapped.

3. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S2, the following sub-steps are also included:

S2-1, set the barrel temperature of the twin-screw extruder barrel zone 1 to zone 10 to: 180℃, 190℃, 200℃, 210℃, 220℃, 220℃, 215℃, 210℃, 205℃, 200℃, set the screw preheating oil temperature of the twin-screw extruder to 80℃, the preheating duration to 30min, and set the vacuum degree of the vacuum system of the twin-screw extruder to –0.08MPa, and set the initial screw speed of the twin-screw extruder to 50rpm. After the torque stabilizes, the screw speed is increased to 200~300rpm;

S2-2, set the premix feed rate to 30 kg/h, add the premix to barrel zone 1 according to the feed rate, and start the twin-screw extruder. The premix passes through barrel zones 1 to 10 in sequence to be melted and plasticized, and finally outputs the melt;

S2-3, filter the output melt through a 80 mesh + 120 mesh double-layer filter screen changer, and set the filter pressure of the screen changer 15MPa, and set the pressure difference alarm value to 20MPa, and judge that the melt that has completed filtration and has not triggered the pressure difference alarm is qualified, and the qualified product is pumped to the pelletizer.

4. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S3, the following sub-steps are also included:

S3-1, the melt is cut and pulled through the die head of the pelletizer to obtain a diameter of 3.0 The melt was in a strip shape of 0.2 mm, the die hole diameter of the die head was 3 mm, the pulling speed was 15 m/min, and the cooling water temperature was 25°C;

S3-2, setting the pelletizer speed to 1200 rpm, the water temperature to 20° C., and the water flow rate to 20 L/min, and underwater pelletizing the strip melt using the pelletizer to obtain initial masterbatches with a length of 2 to 4 mm;

S3-3, setting the centrifuge speed to 1000 rpm and the duration to 2 min, and centrifugally dehydrate the initial masterbatch by the centrifuge to obtain dehydrated masterbatch;

S3-4, setting the temperature of the hot air circulation oven to 80°C for 4 hours, and turning the oven every 1 hour, heating and drying the dehydrated masterbatch in the hot air circulation oven, then stopping heating and naturally cooling the oven to ≤35°C to obtain the rubber and plastic masterbatch;

S3-5, take 5g sample from the rubber and plastic masterbatch, and test the moisture content of the sample by Karl Fischer moisture meter. If the test result is moisture content If the content of 0.05wt% is higher than 0.05wt%, the sampled rubber and plastic masterbatch is judged to be qualified. The qualified products are packed into vacuum aluminum foil bags, sealed and labeled, and the rubber and plastic masterbatch batch is marked. The unqualified products are returned to the hot air circulation oven for further drying.

5. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S4, the following sub-steps are also included:

S4-1, using an electronic scale to weigh 100 phr of rubber and plastic masterbatch and compounding agent raw materials, labeling each portion of compounding agent raw materials with the batch, weigher, and weighing time;

S4-2, nano Add the boron nitride nanosheets to a 1L high-speed dispersing cup and mix at 1000 rpm for 30 seconds to obtain a primary mixed powder. Spray the organic peroxide crosslinking agent dropwise into the primary mixed powder within 30 seconds and mix at 800 rpm for 60 seconds to obtain + Boron nitride + cross-linking agent premix powder;

S4-3, add foaming agent AC and 1phr rubber and plastic masterbatch into a 1L high-speed dispersing cup and mix at 500rpm for 30s to obtain AC-masterbatch pre-coated particles;

S4-4, passing 25°C circulating water through the jacket of the high-speed mixer and running it at no load for 1 minute, then adding materials in sequence within 30 seconds, the sequence including: first adding rubber and plastic masterbatch, then evenly spreading _SiO2 + boron nitride + cross-linking agent premix powder within 10 seconds, and finally adding "AC-masterbatch pre-coated"particles;

S4-5, mixing the materials by the high-speed mixer at a speed of 1000 rpm for 3 minutes. If the chamber temperature of the high-speed mixer is greater than 40°C during the mixing process, automatically injecting 25°C cold air to cool the mixture and outputting the composite material;

S4-6, spread the composite material on a stainless steel tray, and air cool it to After 30℃, put them into double-layer PE bags, vacuum seal and label them, mark the batch of composite materials, and transfer them to the compression molding machine within 4 hours.

6. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S5, the following sub-steps are also included:

S5-1, preheat the mold of the compression molding machine, the preheating temperature is 180℃, and the duration is 20min;

S5-2, preheat the composite material in an oven, set the preheating temperature to 80℃, and last for 10 minutes to obtain the preheated composite material. 1.05 times the amount of the preheated composite material is taken, and the material is added and the mold is closed within 30 seconds to obtain a mold filled with the composite material;

S5-3, placing the mold containing the composite material into a compression molding machine for four-stage compression molding, including:

Initial pressure exhaust stage: no temperature rise, pressure 5MPa, duration 30s;

High pressure setting stage: temperature 180 5℃, pressure 12MPa, duration 6min;

Gradient pressure relief stage: reduce pressure by 2~3MPa every 30s, open the mold 2mm and exhaust for 30s, and the pressure drops to After 8MPa, it goes to the next stage;

Cold pressing and shaping stage: 25°C cooling water, 8 MPa pressure, duration 3 min, after which the compression molding machine automatically ejects and demoulds to obtain a preform, weighs the preform, and records its mass and batch.

7. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S6, the following sub-steps are also included:

S6-1, preheat the foaming furnace to 190℃ for 30min, then place the preforms into the grid of the foaming furnace within 5min, with the spacing between adjacent preforms 15mm;

S6-2, performing three-stage foaming on the preform in the foaming furnace, comprising:

Heating and expansion stage: furnace temperature 190℃, duration 10min;

Shape-keeping and shaping stage: furnace temperature 190°C, duration 2 minutes;

Program cooling stage: stop heating, use frequency conversion to control the fan to reduce the furnace temperature from 190℃ to 50℃ at a cooling rate of 7℃/min, and then cool naturally to the temperature 40℃, output foam memory rubber plastic;

S6-3, with 0.25 The quality of the foamed memory rubber and plastic body is inspected at a density of 0.02g/cm³, and the inspection result is determined as the compression permanent deformation recovery rate. 95% of the foam memory rubber and plastic bodies are qualified products, and are labeled with the foam memory rubber and plastic body batch number, and unqualified products are scrapped.

8. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S7, the following sub-steps are also included:

S7-1, preheating the hot pressing plate of the hot press, setting the preheating temperature to 80°C and the duration to 15 minutes;

S7-2, preheating the foamed memory rubber body in an oven at 60°C for 5 minutes, placing the preheated body into a mirror-finished stainless steel mold, and securing it with positioning pins;

S7-3, performing three-stage hot pressing and shaping on the preheated green body by a hot press, including:

Initial pressing and laminating stage: no temperature rise, pressure 3MPa, duration 30s;

Hot pressing stage: temperature 80°C, pressure 10 MPa, duration 3 min;

Gradient pressure release stage: reduce the pressure by 2 MPa every 10 seconds. After the pressure drops to 2 MPa, take out the hot-pressed green body, and then move the hot-pressed green body and its mold as a whole to the cold press within 30 seconds;

S7-4, pre-cool the cold press plate of the cold press, set the pre-cooling temperature to 0℃, and the duration 10min;

S7-5, cold press the hot-pressed blank into shape using a cold press, set the temperature to 0°C, the pressure to 5 MPa, and the duration to 2 minutes to obtain the shaped material, and record its mass, thickness, and batch.

9. The method for preparing a memory rubber-plastic material with high mechanical properties according to claim 1, characterized in that:

Wherein, in step S8, the following sub-steps are also included:

S8-1, preheat the vacuum oven to 60℃, vacuum –0.09 MPa, duration 15 min;

S8-2, spread the shaped material on the stainless steel mesh plate, place the stainless steel mesh plate with the shaped material into the vacuum oven, and the distance between adjacent stainless steel mesh plates is 20mm, the shaped material is vacuum annealed in the vacuum oven at a temperature of 60°C, a vacuum degree of -0.09 MPa, and a duration of 2 hours;

S8-3, stop heating the vacuum oven, maintain the vacuum degree -0.09MPa and cool naturally to 35℃, memory rubber and plastic material was obtained, with 0.25 The memory rubber and plastic material is sampled at a sampling density of 0.02g/cm³. If the sampling result is compression permanent deformation rate 5%, deformation recovery rate If the content of the memory rubber and plastic material is 95%, the memory rubber and plastic material is determined to be qualified, and the qualified products are put into aluminum foil bags, vacuum-sealed and labeled, and marked as finished memory rubber and plastic materials, and unqualified products are scrapped.