101 results about "Reactive extrusion" patented technology

The invention belongs to the technical field of polymer composite materials, and discloses a large-scale preparation method of a PPS-based composite material with low expansion and high dimensional stability. According to the method, a multi-scale synergistic enhancement system of graphene and nano silicon dioxide is constructed, a maleic anhydride grafted PPS compatilizer is introduced into melt blending, and interface chemical anchoring is achieved through amino-maleic anhydride-epoxy ternary reaction. The filler is premixed according to the mass ratio of 1: 1 after being subjected to surface functionalization, the total content is 15-30 wt%, and the composite material is obtained through twin-screw reactive extrusion and injection molding. The invention provides the large-scale preparation method of the low-expansion high-dimensional-stability PPS-based composite material which is reasonable in structural design, high in process controllability, excellent in performance index and suitable for industrial production, and the problem that thermal expansion suppression and interface strengthening are difficult to consider at the same time in the prior art is solved.

The invention relates to the technical field of multi-layer material preparation, in particular to a high-light-transmittance weather-proof impact-resistant striped sound insulation board. The problem that transparency, weather resistance and sound insulation effect of a traditional stripe material are difficult to consider at the same time is solved. The light scattering and absorption center is reduced and high transparency and low haze are realized through reactive extrusion of the recycled material, combination of high-temperature adsorption activated carbon, multi-stage high vacuum and deep purification of a reactive decolorizing agent, and matching of transparent dispersion diffusion master batch and a compatilizer. The surface layer adopts the core-shell weather-resistant master batch and the secondary high-energy UV fluorosilicone curing coating for double shielding of ultraviolet and inhibition of photodegradation and yellowing; styrene-maleic anhydride damping resin is introduced into the middle layer, and uniform inclined micropores and asymmetric stripes formed by supercritical CO2 are combined, so that the medium and low frequency sound insulation index is improved; the bottom layer is repaired and guaranteed to be durable in impact resistance by virtue of a core-shell toughening agent and molecular chain extension; the defects of traditional products are overcome, and the service life requirement of sound barriers for expressways and rail transit is met.

The invention relates to the technical field of high polymer materials, and discloses a PVC (polyvinyl chloride) pipe for communication wiring and a preparation method thereof, and the pipe is prepared from polyvinyl chloride resin, a calcium-zinc composite heat stabilizer, stearic acid, polyethylene wax, maleic anhydride grafted polyethylene, an acrylate processing aid, nano calcium carbonate and an active lubricating precursor. The active lubricating precursor is a mixture formed by compounding amino-terminated polysiloxane and zinc stearate through heating and swelling. The preparation method of the PVC pipe for communication wiring comprises the steps of pre-preparation of the active lubricating precursor, multi-stage temperature-control high-speed mixing and reactive extrusion molding. Through in-situ chemical reaction of amino-terminated polysiloxane and maleic anhydride grafted polyethylene in the extrusion process, chemical anchoring of lubricating molecules is realized, the problem of precipitation of a lubricant is solved, and meanwhile, the lasting smoothness, impact strength and dimensional stability of the inner wall of the pipe are improved by cooperating with nano calcium carbonate.

This invention discloses an aqueous dispersion of a polyhydroxyalkanoate-grafted ethylene-acrylic acid copolymer with a self-emulsifying core-shell structure, its preparation method, and its recyclable paper packaging, belonging to the field of reactive modification of polymer materials and green packaging technology. This invention employs in-situ reactive extrusion technology to construct stable microparticles with a hydrophobic polyhydroxyalkanoate core and a hydrophilic ethylene-acrylic acid copolymer salt as the shell, overcoming the industry challenge of poor compatibility of bio-based materials. The aqueous dispersion requires no external emulsifier, achieving the same excellent barrier and heat-sealing effects with a lower coating weight, significantly reducing usage costs. Its unique alkali-induced swelling mechanism endows the coating with intelligent peeling properties, achieving efficient separation of the coating and fiber during resizing, greatly improving the purity of recycled fibers.

The present invention relates to a method for preparing esterified flour as resistant starch, through cross-linking by esterification process through hot air oven and alternative method (reactive extrusion), comprising the steps of: for hot air oven, preparing acid aqueous solution; adding flour into the solution; incubating, and drying the slurry in hot air oven to get esterified flour; and washing the flour, and the resistant starch processed by the method thereof and for reactive extrusion, preparing and mixing flour with citric acid aqueous solution; reactively extruding the dried mixed flour; feeding the extruded dried mixed flour; adjusting a screw rotation speed of the extruding machine; stabilizing the weight of the starch citrate extrudate; grounding and sieving the stabilized starch citrate extrudate; and removing unreacted citric acid, and the neutral acid-base resistant starch citrate product processed by the method thereof. The purpose of the invention is to produce resistant starch citrate classified as resistant starch type 4 (RS4) to improve the digestion-resistant property of flour to be the key ingredient of the food helping develop the world food products, in the manufacturing scale, to have properties beneficial to health, as well as to add value to plant- based flour products.

The invention discloses a PC / PET composite material which comprises the following components in parts by weight: 50-60 parts of PC, 15-35 parts of PET, 2-10 parts of graphene, 10-12 parts of mineral powder, 0-6 parts of a flexibilizer, 0.1-1 part of a lubricant and 0.1-0.5 part of an antioxidant, and the mineral powder is modified by a silane coupling agent, methanol and an acid solution. The invention also provides a preparation method and application of the PC / PET composite material. According to the PC / PET composite material and the preparation method and application thereof provided by the invention, PC, PET, mineral powder and graphene with different molecular weight distributions are adopted for reactive extrusion, and a ball milling process is combined, so that the heat conductivity coefficient of the PC / PET composite material is improved, and the balance of rigidity and toughness is kept.

The application relates to the technical field of cable material manufacturing, and discloses a light-weight flexible wear-resistant electrical equipment connecting cable, a sheath of the connecting cable being made of raw materials including the following: polyester type thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, maleic anhydride grafted polyolefin elastomer, blocked isophorone diisocyanate, wear-resistant premixed solution containing a catalyst, slow-release foaming master batch and functional additives; wherein the wear-resistant premixed solution containing the catalyst contains hydroxyl-terminated polydimethylsiloxane and a bismuth octoate catalyst, the slow-release foaming master batch contains modified azodicarbonamide foaming agent and carrier resin, and the functional additives contain antioxidants and carbodiimide hydrolysis stabilizers. According to the application, the hydroxyl-terminated polydimethylsiloxane containing the catalyst and the blocked isocyanate are introduced into the polyurethane matrix in cooperation through a reaction extrusion process, the isocyanate groups are unblocked at high temperature, and the organic silicon chain segment is chemically bonded with the matrix resin.

The invention relates to the technical field of high polymer materials, in particular to a pumice powder modification-based linear low-density polyethylene master batch and a preparation method thereof. The problem that an existing pumice powder modified polyethylene master batch is poor in aging resistance when being used for preparing a film is solved. The master batch disclosed by the invention is prepared from linear low-density polyethylene resin, pumice powder modified by KH-560 and a light stabilizer 944, activated nano zinc oxide, maleic anhydride grafted polyethylene, polydimethylsiloxane, a composite antioxidant and zinc stearate. During preparation, the modified pumice powder and the activated nano zinc oxide are prepared through hydrolytic condensation and loading processes, and then the linear low-density polyethylene master batch is obtained through high-speed premixing and twin-screw reaction extrusion granulation. Finally, a film prepared from the linear low-density polyethylene master batch has good aging resistance.

The application belongs to the field of TPU colorants, and specifically provides a preparation method of a TPU special macromolecular colorant, comprising the following steps: 1) taking oligomer dihydric alcohol, colored dihydric alcohol, chain extender, and isocyanate for standby; 2) uniformly mixing the oligomer dihydric alcohol, the colored dihydric alcohol, the chain extender, and the isocyanate, then reacting and extruding in a double-screw extruder, and then cooling, granulating, and drying to obtain the TPU special macromolecular colorant. The TPU special macromolecular colorant prepared by the application has the advantages of good compatibility, good dispersibility, good migration resistance, and high gloss.

The invention discloses a corrosion-resistant and mildew-proof wood-plastic floor and a processing method thereof, and relates to the technical field of wood-plastic floors, the processing method comprises the following steps: carrying out refined pretreatment on wood powder to obtain fine wood powder meeting the requirements of particle size and dryness; the method comprises the following steps: pretreating a plastic base material through recycled polyethylene plastic particles, removing impurities and adjusting the particle size of the particles; an epoxy functional mildew preventive is synthesized in situ and is used for forming covalent bonding with a wood-plastic matrix subsequently; mixing the pretreated plastic base material, the wood flour and the epoxy functional mildew preventive in sequence to obtain a uniform material; bonding and plasticizing of the materials are achieved through a reactive extrusion process, and a molten profile is formed; carrying out on-line shaping and gradient cooling on a molten profile obtained by reactive extrusion, eliminating internal stress, and carrying out curing molding; and fixed-length cutting and finish machining are conducted on the sectional material subjected to gradient cooling and curing, and the finished corrosion-resistant and mildew-proof wood-plastic floor is obtained.

The invention relates to the technical field of cable insulation materials, in particular to an anti-aging chemical crosslinked polyethylene cable insulation material and a preparation process thereof. The insulating material is prepared from the following components in parts by mass: 50 to 60 parts of low-density polyethylene, 20 to 25 parts of polyolefin elastomer, 10 to 15 parts of maleic anhydride grafted SEBS (Styrene-Ethylene-Butylene-Styrene), 1.5 to 2.5 parts of dicumyl peroxide, 15 to 20 parts of composite flame-retardant filler and 3 to 5 parts of anti-aging composition, the preparation process comprises the following three steps: firstly, preparing the core-shell structure flame-retardant master batch of zinc borate coated talcum powder through ball milling and melt blending; secondly, mixing the anti-aging component with a polyolefin elastomer to prepare an anti-aging master batch; and finally, mixing the matrix resin with the two master batches and the cross-linking agent, carrying out reactive extrusion in a four-section temperature zone (150-195 DEG C), and carrying out water-cooling cutting and drying to obtain a finished product. The insulating material has the characteristics of no toxicity, long-term high temperature resistance, aging resistance and excellent flame retardance, and is suitable for low-voltage to medium-voltage power cables.

The application provides a kind of open-cell foamed polypropylene material and preparation method, and the preparation method of open-cell foamed polypropylene material includes: polypropylene is reacted with first initiator extrusion to obtain low molecular weight polypropylene;Low molecular weight polypropylene is mixed with polypropylene according to preset ratio, second initiator, grafting monomer, antioxidant and the like are melt grafted to obtain short branched chain structure polypropylene;After short branched chain structure polypropylene is foamed, open-cell foamed polypropylene material is obtained.The scheme of the application utilizes low molecular weight polypropylene and grafting monomer to graft together on polypropylene molecular chain, improves the foaming performance and open-cell structure of polypropylene.

The application discloses acetoacetamide modified polyvinyl alcohol and a preparation method thereof, and the preparation method comprises the following steps: reacting p-ester and an acetoacetamide reagent at 20-80 DEG C for 1-3h in a polar solvent to generate N-acetoacetyl p-ester; then, the N-acetoacetyl p-ester is mixed with an alkaline catalyst and polyvinyl alcohol, and is added into a double-screw reaction extruder to generate N-acetoacetyl p-ester modified polyvinyl alcohol crude product; finally, the crude product is powdered, washed with methanol for three times to remove the catalyst and reaction inorganic salt, and is filtered and dried to obtain the N-acetoacetyl p-ester modified polyvinyl alcohol. The AAE-PVA prepared by the application can be used as a protective colloid for polyvinyl acetate emulsion polymerization, has better water resistance than common polyvinyl alcohol, and the water resistance, tensile strength and stability of the prepared emulsion adhesive are obviously improved. The synthesis steps of the application are simple, the safety risk is low, and the reaction yield is high.

The invention belongs to the field of high polymer materials, and discloses a method for efficiently catalytically synthesizing polylactic acid, which is characterized by comprising the following steps: adding lactide, a tin catalyst and an initiator into a reactor, quickly heating to 180 + / -20 DEG C under the protective atmosphere and stirring, and carrying out polymerization reaction for more than 10 minutes to obtain high-molecular-weight polylactic acid; the initiator is hydroxy acid and is monobasic acid. The lactide polymerization rate is greatly improved, the polymerization reaction can be completed within more than ten minutes, the lactide conversion rate is 94% or above, the molecular weight is 2.17 * 10 < 5 > Da or above, and the lactide reaches the level of commercial polylactic acid. Compared with a tin catalyst and a tin catalyst / alcohol composite catalytic system, the catalytic system has the advantages that the polymerization rate at the initial reaction stage is increased by 20-30%, and the reaction time is shortened by more than 80%. The catalytic system is applied to a process for synthesizing polylactic acid through reactive extrusion, and the production efficiency of an extruder can be remarkably improved.

The present application relates to a kind of polyglycolic acid biodegradable block copolyester film, mainly solve the existing polyglycolic acid material poor mechanical properties in prior art and cannot meet the application problem.The polyglycolic acid block copolyester film includes: 70~90 parts of polyglycolic acid and derivative block by mass percentage, 10~30 parts of polyethylene glycol block.In the present application, the required amount of glycolic acid and derivative, polyethylene glycol, reaction extrusion in double screw extruder, granulation drying, extrusion blowing film or casting is obtained after the described polyglycolic acid biodegradable block copolyester film, the obtained film material has excellent bonding performance.

The invention relates to the technical field of metallocene polyethylene materials, in particular to an FFS heavy packaging film and a preparation method thereof. The problems of balance contradiction between rigidity and impact resistance of a traditional product and narrow heat-sealing window are solved. A finished product is prepared from modified metallocene polyethylene, POE grafted zinc salt ionomer, core-shell structure toughening particles, linear low-density polyethylene, functional filler and a processing aid. Polarization and ionization modification of metallocene polyethylene and POE are achieved through reactive extrusion, and the puncture resistance of the material is improved through the physical cross-linking effect of ion clusters and the multi-stage toughening effect of core-shell particles; and meanwhile, by virtue of the cooperation of the thermal reversibility of the ionomer and a specific film blowing process, the initial temperature of heat sealing is reduced, and the sealing safety problem in a dust environment is solved.

The invention discloses a preparation method of a high-performance polyethylene gas pipe, and belongs to the field of polyethylene gas pipe manufacturing. A core-shell structure topological entanglement polymer directly grows on the surface of a polyvinyl base material particle through an in-situ interfacial polymerization technology, a flexible highly-branched core layer is responsible for stress dispersion, a shell layer with a reactive functional group is used for subsequent compatibilization, and then serial melting reactive extrusion is carried out, so that the core-shell structure topological entanglement polymer is obtained. The preparation method comprises the following steps: carrying out in-situ reaction on a main toughening agent POE-g-GMA and an active functional group generated after deprotection of a topological entanglement polymer to form a PE-entanglement agent-POE chemical compatibilization structure, and finally carrying out pipe extrusion molding and online microwave heat treatment to promote post-curing and chain segment rearrangement. According to the invention, the problems of interfacial compatibility and dispersity of a multiphase system are fundamentally solved, molecular-level compounding is realized, and the prepared gas pipe has ultrahigh toughness, excellent crack propagation resistance and good long-term durability.

The invention relates to the field of engineering plastic composite materials. The invention relates to a low-warpage toughened polyhexamethylene adipamide material and a preparation method thereof. The preparation method comprises the following steps: synergistically compounding polyhexamethylene adipamide, glass fiber, polyhexamethylene adipamide-silicon dioxide reaction composite master batch and maleic anhydride grafted ethylene-1-octylene copolymer master batch, and carrying out reactive extrusion and blending granulation to obtain granules. The warping amount of a flat plate part formed by material injection molding is 0.10-0.60 mm, and the notch impact strength is 8-25 kJ / m. The problem that low warping and toughening of the polyhexamethylene adipamide glass fiber reinforced material are difficult to consider at the same time is solved. The method is suitable for injection molding products.

Polyurethanes and polishing articles made therefrom including a reaction product of a reactive mixture including a polyol, a diol chain extender, a diisocyanate, a mono-alcohol, and a multifunctional amine are described. The mole ratio of isocyanate groups to hydroxyl groups in the reactive mixture is 0.98 or greater. Such polyurethanes may remain stable even at extended exposure to elevated reactive extrusion temperatures.

The invention discloses a method for synthesizing 3-bromine-9-ethyl carbazole through reactive extrusion. The method comprises the following reaction steps: (1) adding uniformly mixed 9-ethyl carbazole, N-bromosuccinimide and a solid diluent into a solid feeding bin of a double-screw extruder; (2) adjusting the feeding speed and the screw rotating speed of the double-screw extruder, and dropwise adding auxiliary liquid through a peristaltic pump; and (3) collecting the product, dissolving, filtering, evaporating to remove the solvent and the like to obtain the 3-bromine-9-ethyl carbazole. According to the present invention, the double-screw extruder is adopted to efficiently prepare the 3-bromo-9-ethyl carbazole through the reaction extrusion, such that the use amount of the toxic and harmful solvent is substantially reduced, the product yield is improved, and the good application prospect is provided.

The invention relates to the technical field of plates, in particular to a matte anti-dazzle polycarbonate plate and a preparation method thereof. The formula of the plate mainly comprises bisphenol A polycarbonate resin, a specifically prepared hydroxyl-terminated carbonate oligomer, a double-grafted multifunctional epoxy chain extender and the like. A uniform microscopic scattering structure is constructed in a matrix through transesterification, and chain extension, interface wetting and ultraviolet shielding are synchronously realized by using a double-grafted chain extender. During preparation, a reactive extrusion process of sectional feeding is adopted, and gradient cooling and annealing treatment of three-roller calendering are combined. The method effectively solves the problems of low light transmittance and non-uniform haze caused by dependence on inorganic filler or surface coarsening in the traditional technology, realizes unification of high light transmittance, low glare, high definition and excellent weather resistance, and is particularly suitable for the high-end display fields such as vehicle-mounted display, education tablet and the like.

The invention belongs to the technical field of compositions of high-molecular compounds, and relates to a high-barrier antibacterial rubber-plastic composite material and a preparation method thereof. The material is composed of 45%-65% of polyvinyl fluoride, 20%-35% of a bio-based polyester elastomer, 1.5%-4.0% of silver-loaded zirconium phosphate, 0.8%-2.5% of a bismaleimide compatibilizer and the balance of a processing aid. Wherein the side chain of the elastomer contains carboxyl or epoxy group, the elastomer and the polyvinyl fluoride form a covalent bond interface through in-situ reaction, and the antibacterial agent is anchored on the interface through silane coupling treatment. The preparation method comprises the steps of pretreatment, primary mixing, reactive extrusion and granulation molding. According to the invention, a bio-based polyester elastomer with reaction activity is introduced through molecular design, and a rubber-plastic composite material system with high barrier property, high toughness, long-acting antibacterial property and good processability is successfully constructed in combination with reactive compatibilization and interface directional anchoring antibacterial strategies; and a reliable material solution is provided for the fields of functional packaging, medical protective films, intelligent flexible devices and the like.

This invention discloses a method for preparing organosilicon for low-smoke halogen-free wires, relating to the field of wire and cable technology. The method includes premixing a raw material formulation to obtain a premix; the raw material formulation includes: SEBS substrate, aluminum hydroxide, magnesium hydroxide, styrene-grafted organosilicon anchoring agent, long-chain vinyl-terminated reactive lubricant, dicumyl peroxide, pentaerythritol tetra(3-mercaptopropionate), and an antioxidant; the premix is ​​placed in a twin-screw extruder, and an organosilicon system is formed in the SEBS substrate through reactive extrusion. This invention, through a synergistic process of anchoring-controlled reaction-purification, exhibits excellent processing stability and a low coefficient of friction during high-speed extrusion, while maintaining high mechanical properties, high batch consistency, and long-term service stability.

This invention discloses an environmentally friendly biodegradable plastic packaging material and its preparation method, belonging to the technical field of polymer biodegradable packaging materials. It aims to solve the problems of poor compatibility, low melt strength, and slow degradation of existing polylactic acid (PLA) blends. This invention uses PLA as a matrix, introduces a furanyl dicarboxylic acid-pentanediol-itaconic acid copolyester containing side-chain double bonds as a functionalized flexible component, and adds thiol-modified epoxidized soybean oil as a reactive compatibilizer. Chemical linkages between different polymer chains are achieved through reactive extrusion, constructing a cross-linked network structure of thioether bonds. The resulting packaging material maintains good mechanical properties while exhibiting excellent gas barrier properties and biodegradability.

The reinforced degradable drainage plate comprises a degradable tooth-shaped plate core, a reinforced structure embedded into the degradable tooth-shaped plate core and filter membrane layers compounded on the two sides of the degradable tooth-shaped plate core in a hot melting mode. Wherein the degradable toothed plate core is prepared from the following raw materials in parts by weight through reactive extrusion: 40 to 50 parts of polylactic acid, 20 to 30 parts of poly (butylene adipate-co-terephthalate), 10 to 20 parts of starch-based biodegradable resin, 0.5 to 2 parts of maleic anhydride grafted polylactic acid (MAH-g-PLA), 5 to 10 parts of nano calcium carbonate, 3 to 8 parts of plasticizer and 0.5 to 1.5 parts of antioxidant. According to the reinforced degradable drain board disclosed by the invention, the tensile strength and long-term creep resistance of a product are remarkably improved by adopting high-performance bio-based fibers and a reinforced structure; by introducing a reactive melt grafting composite process, high-strength chemical bonding between a reinforced structure and a body material is realized, so that the key peel strength is improved by more than multiple times, and the problems that a composite layer is easy to separate and the overall performance is reduced in the prior art are solved.

The invention discloses a high-toughness flame-retardant PA66 composite material and a preparation method thereof, belongs to the technical field of high polymer materials, and aims to solve the technical contradictions that the toughness and processability of traditional flame-retardant PA66 are greatly reduced due to the fact that a large amount of solid flame retardant is added, and the flame-retardant efficiency is weakened by a flexibilizer. According to the invention, a phosphorus-containing flame-retardant structural unit is introduced into a PA66 main chain, and a reactive compatibilizer and a synergistic elastomer are combined to construct a chemically bonded continuous phase-dispersed phase interface network structure in a melting reaction extrusion process. Based on the cooperative regulation and control of the molecular level and the interface level, the composite material disclosed by the invention still keeps excellent mechanical properties while meeting the high-grade flame-retardant requirement and having a relatively high limit oxygen index, especially shows remarkably improved impact toughness under a low-temperature condition, and has a good application prospect. Therefore, collaborative optimization and balance of flame retardant property and mechanical toughness are effectively realized.

The invention relates to the field of agricultural resource utilization, and particularly discloses saline-alkali soil conditioning particles rich in humic acid and a use method of the saline-alkali soil conditioning particles. According to the technical scheme, the particles are homogeneous particles prepared from the following raw materials in parts by weight through reactive extrusion granulation: 50-65 parts of weathered coal powder, 5-10 parts of maleic anhydride, 20-30 parts of calcium sulfite, 0.1-0.5 part of manganese sulfate, 5-10 parts of alkyl glycoside, 5-10 parts of sodium lignin sulfonate and 5-15 parts of water. The humic acid content of the weathered pulverized coal is greater than or equal to 50.0%, and the granularity of the weathered pulverized coal passes through a 80-120-mesh sieve; the grafting reaction is initiated by using free radicals generated by auto-oxidation of calcium sulfite, an additional organic initiator does not need to be added, organic residues are avoided, meanwhile, chemical modification of humic acid is achieved, the carboxyl content is increased, and the exchange capacity of conditioning particles for sodium ions in soil is improved.

In an embodiment, a polyurethane comprises the residues of i. an aliphatic diisocyanate, ii. an aliphatic diol comprising a poly(ethylene oxide) moiety, iii. an aliphatic diol comprising a polycarbonate moiety, and iv. a chain extender, wherein the polyurethane has a melting temperature of 140° C. or less and has a weight average molecular weight of from 100,000 to 500,000 g / mol. In an embodiment, the polyurethane is substantially devoid of catalyst. In an embodiment, the polyurethane is formed by reactive extrusion. In an embodiment, a medical device comprises the polyurethane and a bioactive agent. The medical devices, methods, and polyurethanes may exhibit benefits in end-product biostability, drug release profile, health and safety, and processing speed or reproducibility.

The invention discloses a preparation method of an MPP electric power protection pipe, and relates to the technical field of power cable pipeline manufacturing, the method comprises the following steps: using low-melt-index block co-polypropylene as a matrix, treating needle-like wollastonite through a high-temperature low-shear coordination activation process, and constructing an anisotropic enhanced skeleton; the method comprises the following steps: premixing hollow glass beads and a compatilizer by utilizing a liquid bridging principle, and realizing interface in-situ chemical anchoring while completely retaining a spherical topological structure of the beads by adopting a side feeding shear-free reaction extrusion process; a gradient cooling strategy of air cooling nucleation and high-temperature sizing is adopted in the pipe forming stage, and a matrix is induced to generate a large number of bunchy beta crystals. According to the invention, the contradiction between rigidity and toughness and between antifriction and processability is effectively overcome, and the ring stiffness, the inner wall smoothness and the low-temperature impact resistance of the pipe are remarkably improved.

The invention discloses a preparation method and device of an EVA hot melt adhesive for packaging, the device comprises a pretreatment drying unit, a precision metering and feeding unit and a multi-stage reactive extrusion unit, the pretreatment drying unit comprises a high-speed mixer, and an inner cavity of the high-speed mixer is provided with a heating module and a vacuum drying module; the precise metering and feeding unit comprises at least three bins arranged on one side of the high-speed mixer in an array mode, precise metering scales are arranged at the bottoms of the bins, and feeders are arranged on one sides of the precise metering scales; the multi-stage reaction extrusion unit comprises a double-screw extruder, and the double-screw extruder is sequentially divided into a melt blending section, a first lateral feeding section, a reaction crosslinking section and a second lateral feeding section in the material conveying direction. The efficient and stable preparation of the high-performance EVA hot melt adhesive is realized, and the bonding strength, heat resistance and comprehensive performance of the product are improved.