91results about How to "High molecular weight" patented technology

The invention provides a production process of a high-wear-resistance and impact-resistance aramid fiber material, and relates to the technical field of material preparation, and the production process comprises the following steps: S1, raw material preparation: selecting a para-aramid fiber prepolymer, a hydroxylated boron nitride nanosheet, N-methyl pyrrolidone, a wear-resistance enhancer and an impact-resistance modifier according to a preset proportion, S2, mixing, S3, polymerization reaction, S5, extrusion molding, S6, extrusion molding, and S7, molding. Transferring the mixed system into a reaction kettle, introducing nitrogen for 35-55 minutes, and replacing air in the reaction kettle to form an aramid polymer; s4, molding processing: cooling the nylon polymer to room temperature, then putting the nylon polymer into spinning solution storage equipment, and winding the stretched fibers; s5, auxiliary treatment, wherein the wound fibers are washed with water and dried; according to the invention, the aramid polymer has a good crystal structure and high molecular weight, the wear resistance of the material is improved, the interface bonding force between the fiber and the matrix can be improved, and the impact resistance of the material is further improved.

This invention relates to the field of catalysts, specifically to a polyethylene catalyst and its preparation method, as well as ultra-high molecular weight polyethylene and its preparation method. The method includes the following steps: (1) under diluent conditions, a magnesium halide precursor, an alcohol compound, and a first internal electron donor undergo a first contact reaction to obtain a first reaction solution; (2) a second internal electron donor is added to the first reaction solution to undergo a second contact reaction to obtain a second reaction solution; (3) a titanium precursor is added to the second reaction solution to undergo a third contact reaction to obtain a third reaction solution; (4) a haloalkane is added to the third reaction solution, followed by a third internal electron donor to undergo a fourth contact reaction. The catalyst prepared by this invention exhibits good catalytic performance.

The application provides a method for synthesizing a polyaromatic ketone compound, and belongs to the technical field of polymer material preparation, and comprises the following steps: in the condition that a high-boiling-point organic Lewis base is used as a solvent and a Lewis acid is used as a catalyst, a Friedel-Crafts acylation reaction is carried out on a polymerization monomer at a reaction temperature of 100-350 DEG C to obtain the polyaromatic ketone compound, wherein the polymerization monomer is: a) an aromatic diacyl halide compound and an aromatic compound containing two active hydrogen atoms; and / or b) an aromatic compound with an acyl halide at one end and an active hydrogen at the other end. The preparation method can obtain a polyaromatic ketone compound with a high molecular weight.

The invention relates to the field of macromolecules, in particular to a polyamide elastomer raw material composition and application thereof, polyamide elastomer and a preparation method thereof. The raw material composition contains polyamide and polyether, wherein at least one end-capping group in the polyamide is an amino-terminated group; at least one end-capping group in the polyether is an ester group. When the raw material composition is used for preparing the polyamide elastomer, the advantages of high reaction speed, high production efficiency and the like are achieved, the reaction controllability is high, the molecular weight of the product is large, and the type, molecular weight and structure of the soft segment can be adjusted according to application requirements, so that the performance of the elastomer is effectively regulated and controlled.

The application discloses a method for preparing polylactic acid by using an organic base-sulfourea dual catalytic system, and comprises the following steps: under the catalysis of the organic base-sulfourea dual catalytic system, ring-opening polymerization of lactide is carried out under the action of an initiator to obtain the polylactic acid; and the sulfourea is disulfourea or trisulfourea. The sulfourea catalyst is easy to synthesize, the organic base-sulfourea dual catalytic system formed by modular combination of the organic base and the sulfourea has a high decomposition temperature, and therefore has good high-temperature resistance, so that the controllable ring-opening polymerization of lactide in a solution can be realized, and the controllable ring-opening polymerization of lactide at high temperature can also be realized; the catalyst used in polymerization is a hydrogen bond bifunctional catalyst, and the controllable polymerization effect that cannot be achieved when only alkali is used for catalysis can be achieved, so that the polylactic acid has a narrow molecular weight distribution; by adjusting the ratio of lactide, the initiator, the organic base and the sulfourea, the catalytic activity can be further regulated, and the polylactic acid with a high molecular weight and a controllable structure can be obtained.

The application discloses a composite solid decoloring powder and a preparation method thereof, and belongs to the technical field of water treatment agent preparation. The modified nano titanium dioxide is obtained by coating titanium dioxide with 3-methyl acrylic acid sulfopropyl potassium salt grafted polydopamine. The titanium dioxide has photocatalytic effect and antibacterial property, can catalytically decompose pollutants in sewage, inhibit the breeding of bacteria in water, and can catalytically decompose free formaldehyde in dicyandiamide formaldehyde polycondensate. The modified nano titanium dioxide is loaded on phenolic resin foam, and after calcination, the nano titanium dioxide / foam carbon powder is formed. The large specific surface area and porous property of the foam carbon can increase the capture and fixation of free formaldehyde, and can synergistically accelerate the catalytic degradation of formaldehyde with the titanium dioxide. The dicyandiamide formaldehyde polycondensate grafted with castor oil is in-situ polymerized on the surface of the matrix. The castor oil grafting can significantly improve the dicyandiamide formaldehyde polycondensate, significantly increase the molecular weight, and increase the capture capacity.

The invention provides an environment-friendly high polymer material additive as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials, the preparation method comprises the following steps: dissolving beta-cyclodextrin into an anhydrous solvent, adding methacryloyl chloride, controlling the molar ratio of methacryloyl chloride to beta-cyclodextrin to be 1: 1, carrying out substitution reaction, then adding excessive acetic anhydride, and carrying out heat preservation reaction to obtain the environment-friendly high polymer material additive. Carrying out acetylation reaction, and purifying to obtain modified beta-cyclodextrin; adding glycidyl methacrylate, ethylene and modified beta-cyclodextrin into a reaction kettle, and carrying out high-pressure free radical polymerization in the presence of an initiator and a chain transfer agent to obtain the environment-friendly high polymer material additive, wherein the mass ratio of the glycidyl methacrylate to the ethylene to the modified beta-cyclodextrin is (4-8): (88-94): (2-4). According to the prepared additive, the processing rheological property and mechanical toughness of a PCR material are improved, meanwhile, the release characteristic of low-volatility organic compounds is considered, and the application requirements of the fields of automobile interiors and high-end packaging are easily met.

The application relates to the technical field of catalysts, and discloses a preparation method of a supported phosphine phenol nickel catalyst with a sulfonate functional group and application of the catalyst in olefin polymerization, wherein a sulfonate group (-SO 3‑ ) is permanently covalently combined on an aromatic ring of a phosphine phenol chelate ligand and is supported on the surface of a solid carrier such as silicon dioxide and magnesium oxide through ionic interaction; in a ligand synthesis stage, the sulfonate group is introduced into a ligand skeleton through a concentrated sulfuric acid sulfonation reaction to prepare a sulfonate-containing phosphine phenol ligand; the ligand is reacted with a nickel source to prepare a complex, and the target catalyst is obtained through supporting; the sulfonate group is fixed through a covalent bond, the structural stability of the catalyst is significantly enhanced, and the loss of an active component in a polymerization process is effectively prevented.

The invention provides a low-precipitation high-transparency high-toughness polyamide material as well as a preparation method and application thereof. The polyamide material comprises polyamide and a specific small molecule capturing agent. According to the low-precipitation, high-transparency and high-toughness polyamide material disclosed by the invention, residual monomers and oligomers of polyamide are reduced in the production process, so that the precipitation resistance problem is obviously improved, the high transparency of the material is maintained, the low-temperature toughness resistance is realized, and the application range in the fields of medium storage and transportation can be widened.

This invention relates to the field of water-soluble polymer materials technology, and discloses a comb-shaped ternary polymer and its preparation process. The polyacrylamide is polymerized from a backbone monomer, anionic monomer, comb-shaped macromolecular monomer, and optional functional reinforcing monomers under the action of a redox and azo-based composite initiation system. The preparation process includes solution preparation and neutralization, deoxygenation and temperature control, adiabatic polymerization, and post-treatment steps, employing a control strategy combining low-temperature initiation and adiabatic temperature rise polymerization. This invention effectively overcomes the defects of traditional linear polymers—low viscosity retention and poor shear resistance—in high-temperature and high-salt environments by introducing comb-shaped side chains to create a steric hindrance effect. The resulting product possesses ultra-high molecular weight, low water-insoluble content, and excellent solubility, exhibiting excellent salt-resistant thickening advantages and mechanical stability, meeting the oil displacement requirements of harsh reservoir environments.

The invention discloses tackifying emulsion as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The tackifying emulsion comprises the following components in percentage by weight: 45-70% of a tackifying polymer D, 0.5-5% of a dispersing agent and the balance of water, wherein the polymer B is prepared from divinyl benzene, phenol and an alpha-methyl styrene oligomer through a reaction, and the polymer C is prepared from triisobutylene and a divinyl ester compound through a reaction. The emulsion provided by the invention has excellent high and low temperature resistance stability, freeze-thaw stability and wide temperature range applicability, and solves the problems of easy phase separation and narrow use temperature range of the traditional petroleum resin tackifying emulsion.

The application provides a heterocyclic quaternary acid and a preparation method and application thereof. The heterocyclic quaternary acid has a structure shown in formula I, wherein Y is selected from a substituted or unsubstituted heterocyclic group, R1 and R2 are independently selected from a linear or branched alkyl group with 1-6 carbon atoms or a substituted or unsubstituted aromatic ring. 10 The heterocyclic quaternary acid has the advantages of good biological compatibility and low toxicity due to the presence of an amide bond, and is suitable for synthesizing a low-toxicity plasticizer.

This invention discloses a method for the continuous preparation of biodegradable copolyester PBST. The method includes: (1) esterifying terephthalic acid and 1,4-butanediol in a stirred vertical esterification reactor; (2) introducing the product of step (1), succinic anhydride, and 1,4-butanediol into the stirred vertical esterification reactor for further esterification; (3) introducing the product of step (2) into a pre-polymerization reactor for pre-polymerization; (4) introducing the product from the pre-polymerization reactor into a final polymerization reactor for final polymerization; and (5) introducing the product from the final polymerization reactor into a melt thickening reactor for melt thickening, so that the melt index of the reaction product reaches 1-20. According to the scheme of this invention, not only can high molecular weight aliphatic aromatic copolyesters be continuously prepared, but the tensile mechanical properties of the prepared PBST are also significantly better.

The application belongs to the field of engineering plastics, and particularly relates to long-chain polyamide resin with easy processing and high tensile property, and a preparation method and application thereof. The long-chain polyamide resin comprises the following raw material components: component a: aliphatic carboxylic acid compound component; component b: polyamine compound component; and component c: a compound with a structure shown in the following formula (1), wherein n and m can be any number between 1 and 10. The long-chain polyamide resin of the application introduces structural diacid with an asymmetric benzene ring structure, utilizes the asymmetric structure to reduce the crystallinity of the material, and introduces the benzene ring structure to improve the mechanical property of the polyamide material, so that the low processing temperature is realized from the polyamide material component itself, the energy consumption is reduced, and the mechanical property of the polyamide material is ensured. The problem that the processing temperature and mechanical property of the polyamide material and the processing energy consumption are difficult to be considered in the prior art is solved.

The application discloses a salt-resistant water-non-dispersible material for oil well cement and a preparation method thereof. The salt-resistant water-non-dispersible material for oil well cement comprises the following components in the form of weight parts: 100 parts of N,N-dimethyl acrylamide, 3-6 parts of acrylic acid, 10-20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 5-15 parts of a cyclic monomer, 0.1-0.4 parts of a branching agent, 5-15 parts of a cationic monomer, 0.3-3 parts of a crosslinking agent and 400-500 parts of water. The salt-resistant water-non-dispersible material prepared by the application has good salt resistance, can significantly improve the anti-dispersion performance of the cement slurry when used in a salt water and sea water cement slurry system with a NaCl content of 18 wt% or less, and has excellent rheological performance.

This invention provides a method for preparing cyclic polyolefins, belonging to the technical field of preparing cyclic olefin polymers. The method includes: initiating ring-opening metathesis polymerization of cyclic olefin monomers using a catalyst; adding a polar monomer to obtain a mixture of linear block polymers and cyclic polymers; adding a quencher to quench the reaction; and separating to obtain the cyclic polyolefin; wherein the cyclic olefin monomer is selected as C. 5~20 The invention relates to an olefin containing carbon-carbon double bonds; the linear block polymer has polar blocks. By adding a polar monomer with a special structure after the ring-opening metathesis polymerization of a cyclic olefin, the two products can be easily separated in post-processing, yielding the target cyclic polyolefin.

The invention discloses a two-component water-based instant adhesive and a preparation method thereof, the two-component water-based instant adhesive comprises a component A and a component B. The component A specifically comprises the following components: 4.0-4.5 parts of polyvinyl alcohol, 0.1-0.2 part of sodium bicarbonate, 0.15-0.2 part of ammonium persulfate, 0.1-0.2 part of a BYK024 defoaming agent, 25.0-26.0% of vinyl acetate, 8.0-9.0% of a functional crosslinking monomer, 1.0-1.5 parts of methacrylic acid, 1.0-1.5 parts of chloroprene rubber, 0.12-0.15 part of a TEGO Dispers 610S dispersing agent, 10.0-11.0 parts of calcium carbonate, 0.1-0.12 part of sodium benzoate and 50.43-45.63 parts of water; the component B comprises the following components in parts by weight: 7.0 parts of a curing agent, 0.6 part of an accelerant, 1.0 part of a catalyst and 91.4 parts of water. The two-component water-based instant adhesive disclosed by the invention can realize instant adhesion and is harmless to a human body and the environment.

This invention discloses a nervonic acid-rich *Xanthoceras sorbifolium* diester oil and its preparation method, belonging to the field of oleochemical technology. The invention first removes some long-chain monounsaturated free fatty acids from *Xanthoceras sorbifolium* oil through saponification and low-temperature settling. Then, porous organic polymer materials are used to further enrich nervonic acids with higher molecular weight and larger particle size. Glycerol is added to the free fatty acids, and esterification with lipase catalyzes the synthesis of diglycerides, thus obtaining a nervonic acid-rich *Xanthoceras sorbifolium* diester oil. The addition of a compound antioxidant effectively prevents oxidative rancidity of the diester oil. The *Xanthoceras sorbifolium* diester oil prepared by this invention has a rich nervonic acid content, a high diglyceride content, and excellent thermal stability, thus showing good application prospects and value in the field of oleochemicals.

This invention relates to the field of olefin polymerization, and discloses a catalyst composition, an olefin polymerization method using the catalyst composition, and the application of the catalyst composition in olefin polymerization. The catalyst composition comprises: a) a monometallocene compound with the structure shown in formula (1), and b) a co-catalyst component; in formula (1), Cp' is a mono- or poly-substituted cyclopentadienyl or unsubstituted cyclopentadienyl group with 1-20 carbon atoms, a mono- or poly-substituted indenyl or unsubstituted indenyl group with 1-20 carbon atoms, or a mono- or poly-substituted fluorenyl or unsubstituted fluorenyl group with 1-20 carbon atoms; R 1 R 2 R 3 R 4 R 5 and R 6 Each of the following is a hydrocarbon group consisting independently of a hydrogen atom, a halogen atom, or 1-20 carbon atoms; X is a halogen atom. The catalyst composition of this invention has the advantages of high high-temperature catalytic activity, good copolymerization performance, and high molecular weight of the resulting polymer.

This invention provides a high-hardness, scratch-resistant, water-based two-component polyurethane matte black base coat, its preparation method, and its application. The two-component matte black base coat comprises component A and component B. Component A includes a water-based hydroxyl polyurethane acrylic dispersion, a water-based hydroxyl acrylic dispersion, hydroxyl microspheres, a high-pigment carbon black paste, water-based additives, a film-forming aid, and water. Component B includes a curing agent and a diluent. The matte black base coat of this invention exhibits high hardness, scratch resistance, and chemical resistance. It also demonstrates excellent workability, activation period, and surface finish, making it suitable for water-based two-component matte black base coat systems. It is particularly suitable for decorative and protective applications in the plastic paint industry, such as 3C consumer electronics, where extremely stringent requirements for abrasion resistance, scratch resistance, and chemical resistance are necessary.

This invention relates to the field of advanced semiconductor packaging materials technology, and particularly to a low-modulus, high-strength, and low-moisture-absorbing epoxy resin composition and its preparation method. By weight, the epoxy resin composition comprises: 20-60 parts of MAR-type epoxy resin base material one, 15-40 parts of modified masterbatch, 0.01-5 parts of a first catalyst, 30-700 parts of silicon powder, 0-30 parts of additives, and 25-60 parts of curing agent; the modified masterbatch is prepared from: MAR-type epoxy resin base material two, a second catalyst, and HTPB; the curing agent is MAR-type phenolic resin. This invention introduces HTPB into the MAR-type resin system to create a synergistic effect, resulting in a packaging material with low modulus, high strength, and low moisture absorption. The obtained composition can achieve a moisture sensitivity level of MSL1, meeting the high reliability packaging requirements of DFN / QFN and other packaging forms.

This invention discloses a method for preparing a low-residue styrene-maleic anhydride copolymer resin, belonging to the field of polymer synthesis technology. The preparation method includes: dissolving styrene monomer, maleic anhydride monomer, and a bifunctional trithiocarbonate RAFT reagent in an organic solvent, and then performing RAFT controlled free radical polymerization via thermal or photoinitiation. The R group of the RAFT reagent contains a 4-dimethylaminopyridine structure, which directionally enriches maleic anhydride monomer around the polymerization active center through dynamic hydrogen bonding-ion pairing, forcibly forming an alternating copolymer structure; its Z group contains a substituted cyclohexyl peroxyketal structure, which can decompose in situ under thermal or photo-triggered conditions to generate initiating free radicals without the need for an external initiator. This method achieves precise control of the copolymer's molecular weight and sequence structure, resulting in a resin with low free reagent and monomer residues, controllable number-average molecular weight, and a small molecular weight distribution coefficient.

The invention relates to the field of carbonate polymerization, and discloses isosorbide polycarbonate and a preparation method thereof. The preparation method of the isosorbide polycarbonate comprises the following steps: under the action of a ketonic acid metal salt catalyst, taking a dihydroxy compound, diester carbonate and aliphatic dihydric alcohol as raw materials, and carrying out transesterification and polycondensation reaction to obtain the isosorbide polycarbonate. The keto acid metal salt is used as the catalyst for synthesizing the isosorbide polycarbonate, the catalyst is low in price and not prone to inactivation, and the isosorbide polycarbonate with high molecular weight and ideal transparency is catalytically synthesized.

The invention belongs to the technical field of oil exploitation, and particularly relates to a dry powder thickening agent for fracturing as well as a preparation method and application thereof. The thickening agent comprises the following components: (a) 1-vinyl-2-pyrrolidone; (b) a di [2-(methacryloyloxy) ethyl] phosphate ester; (c) 2-(perfluorohexyl) ethyl methacrylate; (d) 4, 4 '-diaminostilbene-2, 2'-disulfonic acid; (e) an initiator; based on 1 mole part of 1-vinyl-2-pyrrolidone, the dosages of the di [2-(methacryloyloxy) ethyl] phosphate ester, the 2-(perfluorohexyl) ethyl methacrylate and the 4, 4 '-diaminostilbene-2, 2'-disulfonic acid are 0.05 to 0.1 mole part, 0.1 to 1 mole part and 0.2 to 0.5 mole part respectively, and the dosages of the di [2-(methacryloyloxy) ethyl] phosphate ester, the 2-(perfluorohexyl) ethyl methacrylate and the 4, 4 '-diaminostilbene-2, 2'-disulfonic acid are respectively 0.05 to 0.1 mole part, 0.1 to 1 mole part and 0.2 to 0.5 mole part. The thickening agent has the advantages of high apparent viscosity, high shear resistance, temperature resistance and high resistance reduction rate, and the resistance reduction rate reaches 70% or above.

The application relates to the technical field of 3D molecule generation, and discloses a 3D molecule sampling optimization method and device, electronic equipment and a storage medium, the method comprising the following steps: step 101, determining an exploration sampling budget and an optimization sampling budget of a current round based on a total sampling budget of the current round; step 102, performing initial sampling based on the exploration sampling budget to obtain an initial 3D molecule set; step 103, determining the sampling probability of each fragment appearing based on the initial 3D molecule set; step 104, continuing sampling based on the optimization sampling budget and the sampling probability of each fragment to obtain an intermediate 3D molecule set; and step 105, determining the exploration sampling budget and the optimization sampling budget of the next round based on the quality of the 3D molecules in the intermediate 3D molecule set, and returning to step 102 until a preset round is completed. The application effectively realizes the synchronous improvement of sampling efficiency and molecule quality.

The application relates to the technical field of polyimide materials, and discloses a high-strength and high-modulus polyimide fiber and a preparation method thereof, which comprises the following steps: mixing aromatic dianhydride and nitrogen-containing organic base unit diamine monomers, and carrying out kettle polymerization to obtain rigid polymerization liquid 1; mixing aromatic dianhydride and flexible diamine monomers, and carrying out kettle polymerization to obtain flexible oligomer polymerization liquid 2; conveying the rigid polymerization liquid 1 and the flexible oligomer polymerization liquid 2 into a screw reactor to carry out secondary reaction, and obtaining polyamide acid spinning liquid; filtering and defoaming the polyamide acid spinning liquid, and obtaining polyamide acid fiber through dry spinning; and carrying out thermal imidization and thermal drawing on the polyamide acid fiber to obtain the high-strength and high-modulus polyimide fiber. The application adopts kettle pre-polymerization + screw final polymerization segmented polymerization, avoids gel explosion polymerization, and considers both high-strength and high-modulus and spinnability of the fiber, and cooperates with a channel in-situ catalytic cyclization to synergistically improve fiber orientation and mechanical properties.

The invention relates to the field of high polymer materials, and discloses heat-storage antibacterial polyamide and a preparation method thereof. The heat-storage antibacterial polyamide comprises a polyamide matrix and heat-storage antibacterial particles dispersed in the polyamide matrix, each heat-storage antibacterial particle comprises a cesium-tungsten bronze inner core and a ZnO shell coating the surface of the cesium-tungsten bronze inner core. According to the heat-storage antibacterial polyamide disclosed by the invention, the ZnO is coated outside the cesium-tungsten bronze, so that the problem of dark color of the cesium-tungsten bronze can be solved, and excessive influence on the photothermal conversion function of the cesium-tungsten bronze can be avoided, thereby ensuring that the polyamide has relatively good heat-storage heating capacity.

This invention belongs to the field of resin preparation technology, specifically relating to a polyphenylene sulfide resin and its preparation method. The preparation method includes the following steps: a composite stabilizer, anhydrous sodium sulfide, and a polar solvent are first mixed; the resulting first mixture undergoes a dehydration reaction to obtain a dehydrated reaction solution; the dehydrated reaction solution is then mixed with p-dichlorobenzene; the resulting second mixture undergoes prepolymerization and postpolymerization sequentially to obtain the polyphenylene sulfide resin; the composite stabilizer includes carbodiimide having the structure of formula I, lithium chloride, and sodium hydroxide; R 1 -(N=C=N) n -R 2 Equation I; n is an integer from 1 to 20; R 1 and R 2 The polymer is independently selected from substituted or unsubstituted alkyl, cycloalkyl, aryl, or aralkyl groups. The composite stabilizer in this invention effectively inhibits excessive hydrolysis by polar solvents, improves reaction efficiency, and controls the polymer molecular structure, thereby obtaining high molecular weight, high yield, and high whiteness PPS resin.

This application relates to the field of metal powder preparation technology, and in particular to a method for preparing silver powder for ultrafine line printing, comprising the following steps: preparing a silver ammonia solution and adding a dispersant, stirring to dissolve, adding a reducing agent solution, and aging to obtain nano-silver sol; forming a mixture of an initiator and deionized water, preparing aqueous solutions of acrylic acid and acrylamide separately, and adding them to the mixture for reaction, cooling and filtering to obtain an acrylic acid-acrylamide copolymer; weighing silver nitrate and deionized water, stirring to obtain solution A; weighing a reducing agent and deionized water, adjusting the pH to 1-2, and then adding the nano-silver sol and acrylic acid-acrylamide copolymer to obtain solution B; rapidly adding solution A to solution B, adding a surface modifier after the reaction is complete, aging, centrifuging, washing, and drying. The silver powder prepared by this application has the advantages of small average particle size, good overall uniformity, and small surface area, making it suitable for the field of ultrafine line printing.

This invention discloses a polyester material, a heat-shrinkable film, its preparation method, and its applications. The raw materials for preparing the polyester material include a diacid, a diol, a chain extender, a stabilizer, and a catalyst; wherein the diacid comprises: 90 mol%~95 mol% polyterephthalic acid and 5 mol%~10 mol% isophthalic acid; the diol comprises: 65 mol%~78 mol% ethylene glycol, 18 mol%~28 mol% 1,4-cyclohexanediol, and 4 mol%~12 mol% diethylene glycol; the chain extender is 2,2'-(1,3-phenylene)-dioxazoline, added in an amount of 0.2%~0.8% of the total mass of the diol and the diacid; the molar ratio of carboxyl groups to hydroxyl groups in the diacid and the diol is 1:1~1.05. The polyester material of this invention possesses excellent transparency, shrinkage rate, and strength, and has a low initial shrinkage temperature, making it particularly suitable for applications such as heat-shrinkable films. This invention also provides a heat-shrinkable film, as well as the polyester material, a method for preparing the heat-shrinkable film, and their applications.