259results about How to "Address mechanical properties" patented technology

The invention discloses a hydroxypolyacrylate emulsion, and a preparation method and an application thereof. The preparation method comprises the following steps: weighing an acrylate monomer and/or a metacrylate monomer, a hydroxyacrylate monomer, an acrylic monomer, an acrylate function monomer and a hydroxy oligomer, uniformly mixing to prepare a monomer mixture, weighing 10-15% of the monomer mixture, and emulsifying by using an emulsifier to prepare a seed pre-emulsion for later use; and adding the emulsifier, sodium bicarbonate and deionized water into a reaction kettle, stirring, rising the temperature of a reaction system, adding an initiator, stabilizing, adding the seed pre-emulsion in a dropwise manner, stabilizing, adding the remaining monomer mixture and the remaining initiator in a dropwise manner, heating, slaking, cooling, neutralizing, carrying out heat insulation, cooling, and discharging to obtain the hydroxypolyacrylate emulsion. A film made by using an aqueous dual-component polyurethane coating prepared from the hydroxypolyacrylate emulsion and an aqueous polyisocyanate curing agent has the advantages of high hardness, high luster and excellent chemical resistance.

A vibrator of a beam type linear ultrasonic motor using bending vibration modes belongs to the technical field of piezoelectric ultrasonic motors and is used for the piezoelectric ultrasonic motors. The vibrator solves the problem that the mechanical output capabilities of the ultrasonic motors are restricted because of low tensile strength and low electromechanical coupling efficiency of ceramic materials in the prior art. The vibrator comprises two driving pads, two end covers, two insulating sleeves, two pairs of piezoelectric ceramics with polarization directions being thickness directions, a flange, two thin-walled beams and mounting bases; wherein, studs extend out from the end faces of the flange along the axis of the flange; each stud is sleeved with a pair of piezoelectric ceramics; an end cover is screwed at the overhanging end of each stud; the tail end of each end cover is provided with a driving pad; each piezoelectric ceramic is composed of two symmetrical half piezoelectric ceramics which are combined after being split; the polarization directions of the two half piezoelectric ceramics are opposite; the splitting lines of the two pairs of piezoelectric ceramics at both sides of the flange are vertical to each other; the polarization directions of the piezoelectric ceramics in each pair are opposite.

The invention discloses a novel electric propulsion system. The system comprises an internal combustion engine, an electric generator, an electric distribution system, a propulsion motor and a propeller, wherein the electric generator is in cable connection with the propulsion motor through the electric distribution system; the propulsion motor is connected with the propeller through a clutch and a speed reducer; both the electric generator and the propulsion motor are synchronous motors; and the propeller is an adjustable pitch propeller. The novel electric propulsion system effectively solves the problems of high investment cost, electric loss, severe harmonic pollution, difficult maintenance and high failure risk due to the adoption of a variable frequency technique by the electric propulsion system in the prior art and also solves the problems of high voltage drop in a system power grid and big torque born by a starting transient mechanical shaft due to the high starting transient current in the electric propulsion system in the prior art. The novel electric propulsion system has little investment, convenient installation and maintenance, a low running cost, high system reliability, low failure risk in a use process and a remarkable economic benefit.

The invention relates to a mechanical operation device for lifting and lowering an oil tube of an oil well. The device comprises an elevator, a supporting frame, a lifting and lowering mechanism, a grounding clamp, a pair of hydraulic tongs, an oil tube conveying mechanism, a hydraulic drive mechanism and an electric control mechanism, wherein the supporting frame, the lifting and lowering mechanism, the grounding clamp, the hydraulic tongs and the oil tube conveying mechanism are matched with the elevator; the hydraulic drive mechanism consists of a hydraulic pump and a hydraulic cylinder; and the electric control mechanism is used for controlling the electric lift of the elevator and controlling the hydraulic pump and the hydraulic cylinder. The device is characterized in that: the main structure forming the device also comprises a frame structure connected with a well mouth; a well mouth flange is arranged at the outer bottom of a main platform of the frame structure; the grounding clamp is fixed on the upper part of the main platform; an elevator base platform and a hydraulic tong platform are arranged on the two sides of the frame structure on the upper part of the grounding clamp; an elevator base is fixed on the elevator base platform to matched the elevator; and the pair of hydraulic tongs is fixed on the hydraulic tong platform. The device replaces the traditional manual operation of hanging and conveying the oil tube with the mechanical operation, so the mechanical operation in an overall process can be realized, the working environment of workers is greatly improved, the labor intensity is greatly reduced, and the labor efficiency is obviously improved.

The invention discloses a lens control method and terminals. The method comprises the following steps: a second terminal receives control information of a first terminal in video communication connection with the second terminal; and the second terminal controls the motion of a lens mechanical device of the second terminal according to the control information. According to the method and the terminals, the problem that the camera mechanical rotation or telescopic device of the opposite party cannot be controlled from the far end in video communication is solved, and the user experience effect is further improved.

The invention discloses a T-shaped linear ultrasonic motor oscillator, which relates to the technical field of a piezoelectric ultrasonic motor and aims at solving the problem that the mechanical output capacity of the prior ultrasonic motor stator is limited. T-shaped front end covers of the T-shaped linear ultrasonic motor oscillator are combined by small end surfaces of three amplitude rods and are arranged in a T shape, a drive foot is connected with a connection position of the amplitude rods, and the three amplitude rods and the drive foot form an integral member; piezoelectric ceramics are polarized along the thickness direction, and opposite to the polarization direction of every adjacent two pieces of piezoelectric ceramics on the same amplitude rod, the polarization ways of the piezoelectric ceramics of two amplitude rods on the same axial line are opposite, each fastening screw passes through a back end cover, the piezoelectric ceramics and a flange and is connected to a blind hole, and the piezoelectric ceramics and the flange are positioned between the back end cover and the amplitude rod, and a piece of electrode plate is arranged between the piezoelectric ceramics and the flange; and an insulating sleeve is fixed outside the fastening screw. The invention is applied to the manufacture field of the ultrasonic motor.

The invention discloses polyester resin for a powder coating for a structural member of an engineering machine. The polyester resin has the acid value of 29-45mgKOH/g, the hydroxyl value of smaller than 6mgKOH/g, the glass transition temperature of 55-65 DEG C, the melt viscosity of 3-6Pa.s and the 180-DEG C reactivity of 80-200S and is mainly prepared by cocondensing the following raw materials in percentage by weight: 30-45% of polyalcohol, 45-55% of aromatic polyacid, 0-2% of aliphatic polyacid, 0-2% of a branching agent, 5-15% of an acidolysis agent, 0.005-0.15% of an esterification catalyst, 0.04-0.3% of a curing accelerator and 0.1-1% of an antioxidant. The invention also discloses a preparation method of the polyester resin. The polyester resin disclosed by the invention is of a TGIC-cured type, has favorable weather resistance, corrosion resistance, mechanical property and low-temperature curing characteristics and can be used for solving the problems of frosting and curing incompleteness existing at present when being applied to the powder coating for the structural member of the engineering machine.

An ultra violet radiation resistant environmental protection sheathing material is mainly prepared by the following materials according to the parts by weight: 40-50 pars of polyvinyl chloride resin, 6-8 parts of trioctyl trimellitate, 4-6 parts of dioctyl sebacate, 7-9 parts of dioctylphthalate, 4-6 parts of ca-zn composite stabilizer, 1-1.5 parts of epoxidized soybean oil, 1-1.5 parts of diantimony trioxide, 1-1.5 parts of diantimony trioxide, 10-13 parts of magnesium hydrate, 8-10 parts of refined calcium carbonate, 8-10 parts of titanium dioxide, and 0.3-0.5 parts of ultraviolet absorbent. The invention technically solves the difficult point of compound formulation of the ultra violet radiation resistant white sheathing material, greatly increases the resistance to ultra violet radiation performance of the product, has strong practicability and lays the material foundation for the design and development of resistance to ultra violet radiation coaxial-cables. Based on the resistance to ultra violet radiation white polyvinyl chloride sheathing material, the resistance to ultra violet radiation environmental protection sheathing material technically solves the technical difficulties of resistance to ultra violet radiation performance, softness, UL mechanical physical property, ROHS environment requirements and the like which are difficult to be achieved completely, meets the strict requirements of the application of products on tropical and subtropical regions and has remarkable social effect.

A full-automatic ultrasonic cleaning machine for nickel-based conductor materials is of a closed structure and comprises first ultrasonic rough cleaning tanks, second ultrasonic cleaning tanks, a heat soaking rinse tank, a steam bath wash tank, a hot air internal circulation tunnel type drying box, an automatic portal lifting and travelling mechanism and an electrical control system. According to the full-automatic ultrasonic cleaning machine for the nickel-based conductor materials, automatic all-round cleaning can be conducted, a net bag containing nickel pieces does not need to be rolled over manually, and cleaning can be conducted in place. Besides automatic cleaning, an automatic drying function can also be achieved, original manual airing is omitted, and the nickel pieces are prevented from secondary contamination. Further, an active carbon adsorption device is arranged at an air outlet of the cleaning machine, residual volatile cleaning agents brought out during drying can be effectively adsorbed, and the cleaning agent is prevented from contaminating the air.

The invention belongs to the technical field of polyethylene materials and particularly relates to a flame-resistant polyethylene material with a good tensile strength and a high breaking elongation rate and a preparation method thereof. The polyethylene material comprises the following components in parts by mass: 20-40 parts of high density polyethylene (HDPE), 50-100 parts of ethylene-vinyl acetate copolymer (EVA), 40-70 parts of magnesium hydroxide, 5-15 parts of surfactant, 8-20 parts of red phosphorus, 5-20 parts of silicane cross-linking agent, 1-5 parts of lubricant and 1-3 parts of antioxidant. The preparation method provided by the invention comprises the specific steps of: mixing the high density polyethylene and the ethylene-vinyl acetate copolymer with the Mg(OH)2, the red phosphorus and the surfactant and simultaneously adding the silicane cross-linking agent, and fully mixing the mixture; adding the lubricant, the antioxidant, dispersant and the like into the blended materials, and pelleting the blended materials by extruding from an extruder at a temperature of 120-250 DEG C; and drying to obtain the finished product. The polyethylene material prepared by the invention not only has a good flame resistance, but also has good tensile strength and high breaking elongation rate.

The invention discloses a rope descending device, which consists of a fixed supporting object, a safety rope, a safety belt, a safety belt connecting rope and a descending device. The invention mainly relates to the fields of rope descending, speed limiters and speed limiting pulleys. The fixed supporting object provides a supporting point for the safety rope; and the safety belt and the safety belt connecting rope are connected with the descending device and a person. The descending device has a rope groove for clamping the safety rope and can slide down along the safety rope. Or the descending device is used in a fixed pulley mode. The descending device consists of a base, a T-shaped suspending rod base, a T-shaped suspending rod, a selectable limiting plate, a speed limiter or a manual control handle, and a symmetric design can prevent a reverse installation problem. Descending devices fall into a single rope type and a double rope type according to the number of rope grooves; and according to speed control mode, descending devices fall into a manual type, an automatic type and a manual-autonomic type. The automatic descending device is provided with a speed limiter for controlling the descending speed automatically and is used as a speed limiting dynamic/fixed pulley. The invention also provides a common speed limiter based on a centrifugal force and friction self-locking principle. The rope descending device is simple, safe and reliable in structure and operation and suitable to be used for emergence escape from high-rise buildings.

The invention relates to a method for storing massive industrial equipment monitoring data by means of a non-relation database, and belongs to the technical field of computer database management. At first, a plurality of unstructured data management systems form a non-relation database cluster of a distributed structure, the massive industrial equipment monitoring data are read from a relation database, the read monitoring data are stored into multiple client machines in a form with text files are separated by commas, a non-relation database storage mode is constructed, and the text files separated by commas and on the client machines are led into the non-relation database cluster. According to the method, the massive equipment monitoring data can be effectively stored, rapid data inquiring and analyzing are supported, enterprises can inquire and analyze the massive monitoring data, information having commercial value in the monitoring data is excavated, and finally the purpose of providing references for designing, manufacturing, marketing, using, maintaining and other aspects of industrial production is realized.

The invention relates to machine-made dry-mixed plaster mortar suitable for mechanized spraying. The mortar is composed of the components of, by mass, 0-60% of limestone, 0-60% of limestone tailing, 0-28% of yellow sand, 9-25% of cement, and balance of an additive. The limestone and the limestone tailing are not simultaneously 0. The additive is a mixture of hydroxypropyl methyl cellulose ether, starch ether, re-dispersible latex powder and a thixotropic lubricant. According to the invention, through changing the component ratio of common plaster mortar, and with the additive and thickening agent with special performances, the problems of incapability to adapt to mechanized spraying caused by high angularity, poor fluidity, and high seepage rate of machine-made sand are solved. The mortar is a clean, energy-saving, and highly efficient representative in construction.

The invention discloses polyacrylonitrile/polyethyleneimine/graphene oxide nano porous sponge and a preparation method thereof, and belongs to the technical field of adsorption material preparation. Polyacrylonitrile (PAN), polyethyleneimine (PEI)) and graphene oxide as starting materials are subjected to electrostatic spinning and freeze-drying processes to obtain a porous adsorption sponge material with the PAN (polyacrylonitrile) as a skeleton, the PEI as an adsorbent and a cross-linking agent and the graphene oxide as a reinforcing component. Through the electrostatic spinning technology,the surface of the PAN/PEI double-component nanofiber film is smooth, flat, soft and fluffy. The low-density PAN/PEI porous sponge with good rebound resilience is obtained through the freeze-drying technology. The nano-scale ion exchange fiber prepared by the preparation method is formed by stacking polyacrylonitrile nano-fiber with uniform size, and has excellent adsorption performance to metal ions and organic dyes.

The invention discloses a novel water-based ink binder self-crosslinking emulsion for flexographic printing and a preparation method of the novel water-based ink binder self-crosslinking emulsion. Theself-crosslinking emulsion is a copolymer emulsion prepared from the following components through emulsion copolymerization, by weight, 30-70 parts of deionized water, 5-35 parts of water-based resin, 2-40 parts of alkyl acrylate monomer with the total carbon number being 4-12, 0-25 parts of methacrylate monomer with the total carbon number being 5-10, 0-25 parts of a styrene monomer, 0.2-5 partsof a hydroxyl (meth)acrylate monomer, 0.5-5 parts of a crosslinking monomer, 0.01-0.5 part of a metal ion crosslinking agent, 0.01-0.1 part of an initiator and 0-10 parts of a pH regulator. The water-based ink binder self-crosslinking emulsion can be subjected to a self-crosslinking reaction at room temperature, and has excellent resolubility, water resistance and printing transfer performance.

The invention provides a preparation method of high polymerization degree delustering polyvinyl chloride resin. The method includes: adding deionized water, an initiator, a dispersant, a buffering agent, a vinyl chloride monomer, a crosslinking agent and other materials into a polymerization kettle, and carrying out polymerization reaction at a suitable temperature to obtain the high polymerization degree delustering resin with delustering effect. The crosslinking agent is a monomer containing two or more reaction activity functional group structures. The crosslinking agent is added before the polymerization reaction or when the conversion rate is 0.5%-50%, or by a combined way of the two. At an appropriate temperature, the prepared high polymerization degree delustering polyvinyl chloride resin has the characteristics of neat particles, loose structure and good delustering effect. While acquiring a high polymerization degree with an average polymerization degree up to 1700 or more, the product also has good delustering effect, and is suitable for processing high polymerization degree delustering plastic products.

The invention relates to a double-equal pole double-section stator/rotor reluctance generator, comprising two sections of stators and rotors of a salient pole structure or a non-salient-pole structure formed by laminating silicon-steel plates. A stator salient pole is provided with armature concentrated windings or layer windings; the windings are connected in series or in parallel according to the N-N polarity of the armature windings to form a phase, and the windings are connected in series or in parallel according to the S-S polarity of the armature windings to form the other phase; the rotors are equipped with rotating magnetic poles with the same pole number with the stators, and the adjacent pole windings of the rotors are connected in series or in parallel to form a plurality of N and S groups; the rotors can adopt excitation magnetic poles and permanent magnetic poles in different forms and permanent magnetic and electro-magnetic mixed poles, and a rotor excitation device is arranged on a motor shaft; each rotor can be divided into an inner rotor and an outer rotor; and the armature windings can be arranged on the stators or the rotors. In the invention, by adopting an equal-pole-number stator/rotor technology and series/parallel connection dynamic combination of the windings, output voltage can be regulated conveniently, the utilization ratio of the windings is improved, and power density and efficiency of the generator are enhanced.

The invention relates to polyurethane-acrylic ester composite emulsion of a core-shell interpenetrating polymer network structure and a preparation method thereof. The polyurethane-acrylic ester composite emulsion is prepared from polyester polyol, isophorone diisocyanate, reactive diluent, a hydrophilic chain-extending agent, trimethylolpropane, dihydric alcohol, dibutyltin dilaurate, hydroxyethyl acrylate, a neutralizing agent, water, an aqueous phase chain-extending agent, an initiating agent and initiating agent diluting solvent. The polyurethane-acrylic ester composite emulsion and the preparation method thereof have the following advantages that the problem that water resistance is lowered due to addition of emulsifier is solved; pollution caused by organic solvent and tediousness of the later-period organic solvent extraction technology are avoided. The emulsion is polyurethane-acrylic ester copolymer emulsion of a core-shell crosslinking interpenetrating polymer network structure.

The invention relates to a yam plantation method, in particular to a mechanical directional half sleeve pipe yam ridge cultivation method which comprises the following steps: (1) carrying out deep plowing in winter to improve soil structure and reduce the diseases, pests and of harmful grass in yam land; (2) mechanically ridging in the middle ten days of April in spring by using a yam land ridging machine, wherein the heights of the ridges are 35-40cm; (3) directionally cultivating by using half sleeve pipes; and (4) mechanically harvesting in the middle or last ten days of October by using a yam harvesting plough. The invention has the advantages of saving yam planting and harvesting cost, creating the novel convenient, efficient, directional and labor-cost saving yam cultivating mode, overcoming the defect that the underground water level raises to cause adverse effect to the formation and the yield of the yam which is the tuber crop, solving the problems of mechanical ridge cultivation, high-density planting and mechanical harvesting and promoting the large-scale intensified and industrialized yam production. Due to the adoption of the method, the labor intensity is greatly reduced, the labor efficiency is improved, and the ridges are uniform and have good shapes.

The invention belongs to the technical field of inorganic hybridized polymer materials and particularly relates to inorganic hybridized mixed-etherified melamine resin and a preparation method thereof. The preparation method mainly includes steps: (1) etherification reaction, to be more specific, adding hexamethylol melamine, methyl alcohol and butyl alcohol into a reactor, and performing thermal reaction to obtain tetra-etherified or penta-etherified melamine resin; (2) alkali neutralization; (3) hybridization reaction; (4) distillation for removing residual methyl alcohol and butyl alcohol; (5) cooling and filtering to obtain a finished product. The inorganic hybridized mixed-etherified melamine resin prepared according to the method has advantages that by hybridization cross-linking reaction with inorganic hybrid compounds, high-temperature flame-retardant elements such as boron, molybdenum and stibium are added into amino resin generated finally, and accordingly high temperature resistance and flame retardation of the amino resin are improved, and the resin is mainly applied to preparation of combined polyether and paint.

The invention provides a river channel dredging, screening and mud-cleaning method and equipment. A combined lifting structure operating under action of negative pressure is adopted, stone with a large density and floating rubbish with a small density are screened out by means of dead load from rubbish mixed with mud and are respectively collected. A mud pump (4) is installed on one side of a boxbody (1). The lower portion of the other side of the box body (1) is provided with a mud pipe (5). The inner end of the mud pipe (5) communicates with a stone collecting device (3) vertically installed in the box body (1) through a mud jet opening (12). A floating rubbish screening box (2) is installed on the top of the stone block collecting (3). The problems that rubbish in small and medium-sized river channels are complicated and diversified, and mechanical operation is difficult are solved. The interception ratio of the stone and the floating rubbish reaches 90% or over. The river channeldredging, screening and mud-cleaning equipment is high in self-suction capacity, stable in conveyance and operation, simple and compact in structure and convenient to assemble, disassemble and maintain. The dredging construction efficiency is significantly improved, labor is liberated, mechanization of dredging of the small and medium-sized river channels is facilitated, and the river channel dredging, screening and mud-cleaning equipment is suitable for use and popularization.

The invention discloses a toughening agent with a chain extension function. Under a nitrogen environment, a total monomer and an initiator are jointly and dropwise added into a chain transfer agent contained organic solvent with the temperature of 50 DEG C-70 DEG C, and the dropwise adding time is 2-3 hours; after dropwise adding is ended, the reaction continues for 2-6 hours, and a product is sequentially washed, filtered and dried; and the toughening agent is prepared through a polymerization reaction of a solvent, and the epoxy value is about 4*10<-3> mol/100g to 5*10 <-2> mol/100g. A preparation process of the toughening agent is simple, the reaction conditions are mild, the activity is moderate, and a good chain extension function is realized; and a final product has good toughness and excellent tensile property. The toughening agent can be used for recovering and processing hydroxyl-terminated and carboxyl-terminated polycondensate such as PET (polyethylene terephthalate), PBT (polybutylene terephthalate) and the like, and chain extension and toughening of a PET recovery material are realized; and at the same time, the production technology process is simplified, and the operation is easy.

The invention provides a bionic biomineralized artificial bone repair material as well as a preparation method and an application thereof. The material consists of a cross-linked collagen matrix and biomineralized collagen/hydroxyapatite composite powder dispersed in the matrix, wherein the mass ratio of the collagen matrix to the biomineralized collagen/hydroxyapatite composite powder is (9-1) to(1-9). The bionic biomineralized artificial bone repair material provided by the invention is a collage-based bionic biomineralized artificial bone, which can meet a demand of artificial bone and tissue suturing in a clinical GTR or GBR operation; the artificial bone repair material consists of hydroxyapatite and pure collagen, and the two ingredients are major ingredients of human natural tissues, so that the artificial bone repair material is free from toxicity; and influence to a material structure and an osteogenesis effect is avoided, and good biocompatibility is guaranteed. Due to the existence of the cross-linked collagen matrix, problems of a material which can get dispersed easily, and is too high in degradation speed, poor in mechanical performance and the like can be solved; and the bionic construction of nano-hydroxyapatite and collagen is achieved.

The invention belongs to the field of medical materials and particularly relates to a functional wound surface repairing material and a preparation method thereof. The wound surface repairing material is prepared by compounding 7-14 parts of bioactive glass, 0.5-0.7 part of silver nitrate, 0.2-0.6 part of antibiotics, 15-25 parts of degradable polymer and 80-160 parts of deionized water. The functional wound surface repairing material is loaded with silver ions and antibiotics, wherein the silver ions and the antibiotics respectively have bactericidal performance, and the silver ions can enable the antibiotics to more easily enter bacteria to exert synergistic action by increasing the generation of oxygen free radicals and increasing the permeability of bacterial membranes, so that the functional wound surface repairing material has relatively strong antibacterial performance and can solve the problem that bacteria are easy to adhere to the existing wound surface repairing material to cause infection and then the curative effect is not ideal.

The invention belongs to the technical field of inorganic hybrid polymeric materials, and especially relates to an inorganic hybrid butylated melamine resin and a production method thereof. The production method mainly comprises the following steps: 1, carrying out an etherification reaction: adding hexamethylolmelamine and butanol to a reaction kettle, and carrying out a heat insulation reaction to obtain tetraetherified or pentaetherified melamine resin; 2, neutralizing with an alkali; 3, carrying out a hybrid reaction; 4, distilling to remove residual butanol; and 5, cooling and filtering to obtain the finished product. A hybrid cross-linking reaction with an inorganic hybrid compound makes boron, molybdenum, antimony and other high temperature-resistant flame retardation elements be introduced to finally generate amino resin, so the high temperature resistance and the flame retardation performance of the amino resin are improved, and the obtained amino resin is mainly used to prepare combined polyether, paints and coatings.

The invention discloses a diode testing device, which comprises an upper clamping plate (1), a lower clamping plate (2) and two metal electrodes (3), wherein the two metal electrodes (3) are connected with two wiring terminals (4) at the left end of the lower clamping plate (2), and a spring (6) and support columns (8) are arranged between the upper clamping plate and the lower clamping plate. The diode testing device is characterized in that the right end of the lower clamping plate (2) is provided with a groove (9), the right end of the upper clamping plate (1) is provided with two protrusions (5), and the protrusions (5) are arranged in the groove (9). The device solves the problems of mechanical damage, poor contact, unfirm fixing, easy forming of large error of testing data and the like of the conventional clamping or crimping testing method when a diode, especially a superfine pin axial packaging diode, is tested.

The invention belongs to the field of daily chemical products, and particularly relates to a hair-loss-preventing plant essential oil combination and a preparation method and application thereof. The combination is composed of tamanu oil, Indian neem oil, sunflower seed oil, linseed oil, meadowfoam seed oil, sesame oil, rosemary essential oil, limepeel essential oil, rosemary extract and the balance alcohol, wherein the tamanu oil, the Indian neem oil, the sunflower seed oil, the linseed oil, the meadowfoam seed oil, the sesame oil, the rosemary essential oil, the limepeel essential oil and the rosemary extract account for 0.5-6% , 1-6%, 2-12%, 0.5-8%, 10-38%, 0.5-8%, 0.1-5%, 3-12% and 0.02-1% of weight of the combination respectively. The hair-loss-preventing plant essential oil combination has nourishing effect on scalp and hair and can strengthen hair root so as to prevent and reduce hair loss.

The invention discloses self-repairing polyurethane based on boron-nitrogen coordination and a preparation method thereof. The preparation method comprises the steps that a hydroxyl monomer and diisocyanate are subjected to a polymer reaction, a functional monomer is introduced in the polymer process, and the self-repairing polyurethane based on boron-nitrogen coordination is synthesized. The problem of contradiction between the mechanical property and the self-repairing efficiency of a polymer material is essentially solved, the polyurethane prepared by the method has excellent mechanical properties such as high strength and high toughness, repeated self-repairing can be realized, the self-repairing condition is mild, and the self-repairing efficiency is high.