360 results about "PEG-terephthalate" patented technology

The invention provides a synthesis method of bio-based poly (ethylene 2, 5-furandicarboxylate) (poly (ethylene 2, 5-furandicarboxylate) for short) and performance application of the bio-based poly (ethylene 2, 5-furandicarboxylate). According to the method, 2, 5-furandicarboxylic acid (FDCA) derived from renewable resources and ethylene glycol (EG) are used as main raw materials, and the high-molecular-weight PEF is prepared through microwave-assisted esterification-polycondensation reaction under the action of a metal catalyst. The prepared PEF has excellent thermal mechanical property and gas barrier property, the glass transition temperature is about 58.6 DEG C, the melting temperature is about 187.4 DEG C, and the thermal decomposition 18% weight loss temperature exceeds 400 DEG C. The PEF material can be biologically degraded under the industrial composting condition, and the degradation speed is higher compared with that of traditional petroleum-based PET polyester. The PEF provided by the invention is suitable for the fields of food packaging films, beverage bottles and fiber materials, has the advantages of biodegradability, heat resistance stability and high barrier property, can partially replace polyethylene glycol terephthalate (PET) and other petrochemical plastics, and meets the requirements of sustainable development.

The invention provides a method for alcoholysis of polyethylene glycol terephthalate, and relates to the technical field of PET degradation. The PET alcoholysis method provided by the invention comprises the following steps: mixing PET, ethylene glycol, a cosolvent and a composite catalyst, and carrying out alcoholysis reaction to obtain bis (hydroxyethyl) terephthalate (BHET). According to the invention, dimethyl sulfoxide is taken as a cosolvent, zinc acetate and 1, 8-diazabicyclo [5.4. 0] undec-7-ene are taken as a composite catalyst, catalysis and solvent effect driving are combined, and ethylene glycol alcoholysis of PET is carried out under the synergistic effect of the composite catalyst and the cosolvent. According to the method, effective decomposition of PET can be achieved at the low temperature (140-155 DEG C) and within the short reaction time (60-100 min), and the yield of BHET is high (66% or above and can reach 80% or above). The method provided by the invention can realize high-efficiency alcoholysis of PET with ethylene glycol.

The invention discloses a method for efficiently depolymerizing polyethylene glycol terephthalate, which comprises the following steps: mixing a PET material, ethylene glycol and a core-shell type magnetic nano composite catalyst, and carrying out alcoholysis reaction at 160-200 DEG C for 30-180 minutes; after the reaction is finished, separating the catalyst from a reaction system through an external magnetic field to obtain a solution containing bis (2-hydroxyethyl) terephthalate; the core-shell type magnetic nano composite catalyst comprises a magnetic FeO core, a SiO shell layer and active metal sites, the FeO core is coated with the SiO shell layer, the SiO shell layer is an insulating inorganic layer and is of a porous structure, the active metal sites are fixed to the surface of the SiO shell layer through coordinate bonds, and active metal is selected from one or more of Co, Ni, Cu, Ce, La and Al. The problems that an existing PET alcoholysis catalyst is easy to dissolve out, difficult to separate, harsh in reaction condition and poor in cycling stability are solved.

The invention provides a low-molecular soluble chelating collector as well as a preparation method and application thereof, and belongs to the technical field of mineral processing. According to the collecting agent, low-molecular-weight ethylene glycol terephthalate serves as a precursor, and isosorbide is introduced for a copolymerization reaction; glutamic acid is introduced as a branched chain unit, and the branching degree and reaction active site density of the molecular structure are remarkably improved by utilizing the polyfunctional group characteristic of glutamic acid. A rigid ring structure and an ether bond of the isosorbide endow the medicament with good water solubility and dispersity, and invalid curling of a macromolecular chain is avoided; the introduction of glutamic acid branched chains greatly increases the number of hydroxyl groups and amino groups capable of reacting with carbon disulfide, so that each molecule carries more xanthate groups, and the adsorption stability and coverage density of the molecule on the surface of arsenopyrite are enhanced. By means of the structure, xanthate functional groups are fully exposed, multi-tooth chelation is easily conducted on the xanthate functional groups and iron and arsenic ions on the surface of arsenopyrite, a strong hydrophobic surface layer is formed, and therefore the collecting selectivity is remarkably improved.

The invention discloses a polyester film for a blue adhesive tape, which is used for binding and packaging a battery of a new energy electric vehicle. The polyester film is prepared from 70-85 parts by weight of high-viscosity polyethylene glycol terephthalate, 5-12 parts by weight of thermoplastic polyurethane, 2-4 parts by weight of siloxane resin powder, 1-3 parts by weight of melamine cyanurate, 2-5 parts by weight of organic modified montmorillonite, 1-3 parts by weight of a coupling agent and 1-3 parts by weight of a coupling agent. 1-3 parts by weight of aromatic polyimide micro powder and 0.3-0.5 part by weight of ethylene glycol monostearate. The invention also discloses a preparation method of the polyester film. The polyester film for the blue adhesive tape is excellent in dielectric strength, flexibility, puncture resistance and flame retardance, the characteristics directly correspond to strict requirements of automobile lithium battery shell packaging, and comprehensive guarantee is provided for safety, reliability and environmental adaptability.

The present application relates to the technical field of current collectors, and specifically relates to a multilayer composite film and a current collector prepared from same. The present application provides a preparation method for the multilayer composite film. The multilayer composite film comprises a layer X, a layer Y and a layer Z from top to bottom; the layer X and the layer Z are made of polyimide, and the polyimide is a polycondensation reactant of carboxylic acid anhydride and diamine; and the material of the layer Y is any one or more of polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenyl ether, polyester, polystyrene and derivatives thereof. The polyimide prepared in the present application solves the problems of low solubility and poor processability of conventional fully aromatic polyimides, and a composite current collector is prepared by using heat resistance and improved surface polarity of polyimides, thereby improving the bonding force between a composite current collector film and a metal layer, and improving the tensile strength of a finished product.

The present invention relates to a process for depolymerizing a polyester feedstock comprising opaque PET, which comprises: a) a conditioning step; b) a step of glycolysis, operated at between 180 and 400° C., a residence time of from 0.1 to 10 h in the presence of diol; c) a diol separation step, at a temperature of between 100 and 250° C., a pressure lower than that of step b) and producing a diol effluent and an effluent rich in monomers; d) a step of separating into a heavy impurities effluent and a prepurified monomers effluent, at a temperature of less than 250° C. and a pressure of less than 0.001 MPa and a residence time of less than 10 min; e) a step of decolourizing the prepurified monomers effluent, by adsorption of a mixture comprising between 20% and 90% by weight of the prepurified monomers effluent and a solvent, at a temperature of between 100 and 200° C., a pressure of between 0.1 and 1.0 MPa and in the presence of at least one adsorbent.

The invention discloses an optical paste film and a preparation method thereof, and relates to the technical field of optical functional materials. The optical slurry film is prepared by taking a polyethylene glycol terephthalate film as a base material and coating an optical slurry coating, the optical slurry coating is prepared from the following raw materials in parts by weight: 12 to 16 parts of nano silicon dioxide, 22 to 28 parts of acetone and butanone mixed solvent, 7 to 9 parts of modified titanium dioxide, 4 to 6 parts of nano zirconium oxide, 30 to 35 parts of modified epoxy resin, 18 to 22 parts of butyl acrylate, 4 to 6 parts of dioctyl sebacate, 2.5 to 3.5 parts of silane coupling agent KH-570, 1 to 1.5 parts of organic silicon flatting agent and 0.6 to 1 part of organic silicon defoaming agent. 1.2-1.8 parts of an antioxidant 1010, 3-4 parts of a photoinitiator 184 and 6-8 parts of bis (4-tert-butylphenyl) iodine hexafluorophosphate; the polyethylene glycol terephthalate film pretreatment material comprises absolute ethyl alcohol and deionized water. The raw materials are scientifically proportioned, the titanium dioxide and the epoxy resin are clearly modified, the preparation process is complete, and the finished product is high in light transmittance, good in weather resistance, adaptive to the requirements of the optical field and high in practicability.

The application discloses a medical natural antibacterial and antiviral mildew-proof wet non-woven fabric and a preparation method and application thereof, and belongs to the technical field of medical polymer materials and textiles. The non-woven fabric is prepared from the following raw materials: polyethylene terephthalate long fibers, polyethylene terephthalate short fibers, vinylon fibers and natural antibacterial and antiviral ultraviolet slow-release glue solution. The non-woven fabric is endowed with natural and non-toxic antibacterial and antiviral effects by using the extract of Chinese herbal medicine effective components. Meanwhile, the mechanical properties and the antibacterial and antiviral capacity of the non-woven fabric can be effectively improved by adding nano materials with far infrared function after surface modification to prepare high-efficiency natural antibacterial and antiviral ultraviolet slow-release microcapsule glue solution. The method improves the added value and application field of the wet non-woven fabric and is convenient for large-scale processing and production. The prepared wet non-woven fabric has excellent performance indexes, good air permeability and an antibacterial and antiviral efficiency of 99.99%.

The present invention relates to a process for preparing bis-(2-hydroxyethyl) terephthalate by depolymerization of a plastic filler comprising PET, comprising: a) a step of depolymerization of the PET in the presence of a diol, so as to have a weight ratio between the diol and the PET of the plastic filler of between 0.3 and 8.0, said step a) comprising a reaction phase operated between 150 and 300°C, b) a step of evaporation of the BHET to produce a BHET-rich stream and a heavy impurity stream, step b) using an evaporator comprising an evaporation zone and a zone for withdrawing the heavy impurity stream, and a section for discharging the heavy impurity stream located downstream of the evaporator, the evaporator being operated at a pressure less than or equal to 0.0010 MPa,and in which the evaporation zone is operated between 120 and 300°C and the heavy impurity stream withdrawal zone and the heavy impurity stream discharge section at a temperature greater than 250°C and less than or equal to 300°C.,

The invention relates to a method for efficiently depolymerizing, decoloring and purifying colored waste polyester, which is characterized by comprising the following steps of: (1) feeding waste polyester, a transition metal salt catalyst and ethylene glycol into a reactor, fully mixing and reacting to obtain a depolymerization solution; (2) adding deionized water into the obtained depolymerization liquid, and continuously stirring to ensure that the whole system still has better flowability at the temperature, so as to obtain a diluent of the depolymerization liquid at the temperature; (3) peroxysulfate is added into the diluent of the depolymerization liquid, and the system begins to be subjected to a decolorization reaction; and (4) recrystallizing the solution obtained after the decoloration reaction is finished, and filtering to obtain the recrystallized depolymerized monomer ethylene glycol terephthalate and recovered ethylene glycol. The depolymerization and decoloration purification method has the advantages of environmental protection, high efficiency and low cost.

A polyester-based woven hook-and-loop fastener including: a woven-fabric and engaging elements, in which the woven-fabric in which a polyethylene terephthalate-based multifilament yarn is a warp yarn and a polyester-based heat-fusible multifilament yarn is a weft yarn is a woven base fabric, a yarn for the engaging elements made of at least one kind selected from the group consisting of a polyethylene terephthalate-based monofilament yarn and a polyester-based multifilament yarn, is woven in parallel to the warp yarn into the woven base fabric, the engaging elements that are formed of the yarn for the engaging elements, that are made of at least one kind selected from the group consisting of a large number of hook shapes and loop shapes, and that rise up from a front face of the woven base fabric, exist on the front face of the woven base fabric, bases of the engaging elements are fixed to the woven base fabric by a melt-solidified material of a heat-fusible component of the the polyester-based heat-fusible multifilament yarn, and the polyethylene terephthalate-based multifilament yarn is made of a copolymerized polyethylene terephthalate containing, as copolymerization components, 1.0 to 2.0 mol % of isophthalic acid with respect to a total amount of dicarboxylic acids and 2.0 to 3.5 mol % of diethylene glycol with respect to a total amount of diols.

The invention relates to the technical field of furniture protective films, in particular to a self-adhesive furniture skin-touch protective film which sequentially comprises an organic silicon release film from bottom to top, the organic silicon release film comprises a base material and a coating, the base material is a transparent polyethylene glycol terephthalate film with the thickness of 80-120 micrometers, and the coating is a transparent polyethylene glycol terephthalate film with the thickness of 80-120 micrometers. The coating is an organic silicon release agent coated on the base material, and the coating weight of the organic silicon release agent is 0.8-1.2 g / m; the pressure-sensitive adhesive layer comprises 60 to 70 weight percent of a compound system of a saturated hydrocarbon block copolymer and a hydrogenated styrene isoprene styrene block copolymer; 25 to 35 wt% of hydrogenated C9 petroleum resin; 3 to 5 weight percent of temperature-sensitive microcapsules; and 2 to 5 wt% of naphthenic oil. According to the invention, through the cooperation of innovative multi-layer structures, the product can maintain excellent comprehensive performance under different parameter configurations, and multiple requirements of the furniture protective film on easy construction, high transparency, strong protection, good touch feeling and aging resistance are met.

The invention discloses a terahertz metasurface biosensor which is modified by a single-stranded DNA (deoxyribonucleic acid) nucleic acid aptamer and is used for specifically detecting a tumor necrosis factor-alpha. Under the simulation condition, the surface of the biosensor is covered with a layer of analyte with the thickness of 20 microns, and when the refractive index of the analyte is changed from n = 1 to n = 2, the theoretical sensitivity of the metasurface biosensor can reach 124.71 GHz / RIU. In an experiment, the metasurface is prepared on a copper-plated polyethylene glycol terephthalate sheet by using photoetching and chemical corrosion processes. Then, according to the characteristic that the nucleic acid aptamer is specifically combined with the tumor necrosis factor-alpha, the nucleic acid aptamer is modified on the surface of the sensor, so that the super-surface biological immunosensor is prepared, the concentration detection of the tumor necrosis factor-alpha is realized, the detection limit reaches 0.1 ng / ml, and the detection sensitivity can reach 13.9 GHz / 1g (ng / ml). Besides, ovalbumin and whey protein with the same concentration are compared and detected, and the result shows that only the tumor necrosis factor-alpha can be obviously distinguished, so that the sensor has a specific detection function. The terahertz metasurface immunosensor provided by the invention realizes the specific detection of the tumor necrosis factor-alpha. The work can be used for biomarker detection and early diagnosis of diseases.

The invention relates to a copper cluster scintillator constructed on the basis of diphenyl-2-pyridine phosphine and cuprous iodide and a preparation method and application of the copper cluster scintillator. The preparation method comprises the following steps: constructing a copper cluster scintillator by using diphenyl-2-pyridine phosphine and cuprous iodide, and preparing the copper cluster scintillator into a semitransparent scintillator film by using polyvinylpyrrolidone as a high-molecular polymer matrix and polyethylene glycol terephthalate as a spin-coating substrate; the scintillator film and a photomultiplier are optically coupled and integrated with nuclear electronics equipment to develop an alpha / beta particle pollution monitor. The copper cluster scintillator provided by the invention has excellent X-ray luminescence performance, and can realize high-sensitivity scintillation response to alpha / beta particles; the surface pollution monitor can realize sensitive detection of alpha / beta particles in the environment, and has important application value in the field of environmental radiation detection.

The invention belongs to the technical field of textile, and particularly discloses a porous polyester fiber and a preparation method thereof.The preparation method comprises the following steps that S1, coffee charcoal powder, bamboo charcoal powder and coconut shell charcoal powder are mixed according to the mass ratio of 1: (0.5-2): (0.1-1) to serve as an antibacterial agent; s2, mixing the antibacterial agent, polyethylene glycol terephthalate and a water-soluble polymer to obtain a blend; s3, the blend is sliced, granulated and subjected to melt spinning, and the polyester fiber is prepared; and S4, washing the polyester fiber with alcohol at room temperature, washing with hot water, and drying to obtain the porous antibacterial polyester fiber. Coffee charcoal powder, bamboo charcoal powder and coconut shell charcoal powder are compounded to form an antibacterial agent, then the antibacterial agent is mixed with polyethylene glycol terephthalate and a water-soluble polymer, slicing granulation and melt spinning are conducted, then the water-soluble polymer is dissolved out through alcohol washing and hot water washing, and the polyester fiber with the antibacterial function and the porous structure is obtained.

The invention belongs to the technical field of resource circulation, and mainly relates to a method for recovering polyethylene glycol terephthalate from a retired photovoltaic module backboard. The method comprises the following steps: after crushing a laminated part without an aluminum frame and a junction box, mixing the crushed laminated part with an alkaline alcohol solution to obtain a fluorine-containing backboard; and mixing the fluorine-containing back plate with a binary eutectic solvent, and carrying out heating reaction to obtain the fluorine film and PET (Polyethylene Terephthalate). According to the method, the eutectic solvent is selected as a selective separation solvent, and the binder impurities in the backboard composite material are selectively dissociated through temperature regulation and control, so that complete stripping and high-purity recovery of the PET layer are realized. The separation method is safe, efficient, simple to operate and environment-friendly, and provides a safe and sustainable technical route for recycling the PET material in the retired photovoltaic module.

The invention belongs to the field of photovoltaic modules, and particularly relates to a light conversion adhesive film, a photovoltaic module and application. The light conversion adhesive film comprises a shielding barrier layer, a light conversion adhesive film layer arranged on one side of the shielding barrier layer and a UV shielding adhesive film layer arranged on the side, away from the light conversion adhesive film layer, of the shielding barrier layer, and the shielding barrier layer is made of one or more than two materials selected from polycarbonate, polyethylene glycol terephthalate and polyamide. The light conversion adhesive film disclosed by the invention has high-efficiency light conversion and complete ultraviolet shielding, and can meet the high adhesive property requirement of more than 60N / cm when being adhered with TCO (Transparent Conductive Oxide); the packaged HJT assembly has the characteristics of UV aging resistance and damp-heat aging resistance.

The invention discloses polyethylene glycol terephthalate hydrolase PmPETase and application thereof.The hydrolase PmPETase is protein with the amino acid sequence shown in SEQ ID NO.1. An expression system suitable for the PmPETase is constructed, recombinase protein with catalytic activity is obtained, and the polyethylene glycol terephthalate hydrolase PmPETase can be used for preparing the polyethylene glycol terephthalate hydrolase PmPETase. The substrate specificity, the catalytic property and the potential plastic degradation capacity of the PET degrading enzyme are comprehensively analyzed, and a new theoretical basis and application reference are provided for development and utilization of the PET degrading enzyme and a high polymer material green treatment technology.

The present application relates to a kind of polyethylene terephthalate foamed materials and its preparation method, the preparation method includes the following steps: polyethylene terephthalate material is heat pressed, and the preform of molten state is obtained;The preform of molten state is treated with melt isothermal crystallization and quenching, and sheet material is obtained;And the sheet material is treated with foaming, and polyethylene terephthalate foamed material is obtained.The present application uses melt isothermal crystallization treatment, can improve the melt strength in the foaming process of polyethylene terephthalate, strengthens its foaming performance, simultaneously can also be realized by strengthening bubble nucleation and controlling bubble growth to adjust the bubble morphology of foamed material, so can obtain the polyethylene terephthalate foamed material of bubble size uniform and controllable foaming ratio.

The invention belongs to the technical field of nano-particles, and particularly discloses fluorescent polyethylene glycol terephthalate nano-particles and a preparation method thereof. The preparation method comprises the following steps: crushing and alkali-washing a raw material containing polyethylene glycol terephthalate in sequence to obtain polyethylene glycol terephthalate particles; mixing the mixed solution with an organic solvent to obtain a mixed solution, mixing the mixed solution with a polyethylene glycol terephthalate particle poor solvent, and filtering to obtain polyethylene glycol terephthalate nanoparticles; the nano-particles are mixed with tween-20, and nano-particle dispersion liquid is obtained; and carrying out swelling reaction on the nano-particle dispersion liquid and a tetraphenyl ethylene solution to obtain the fluorescent polyethylene glycol terephthalate nano-particles. According to the invention, the particle size and shape of the nanoparticles can be accurately controlled, the consistency of products is improved, and the phenomena of sedimentation and aggregation are reduced. By controlling the aggregation state of molecules, fluorescence quenching is effectively avoided, and the defect that traditional organic fluorescence aggregation is easy to quench is overcome.

The invention provides a polymer floor and a preparation method thereof. The floor sequentially comprises a first outer layer, a first buffer layer, a first bonding layer, a base material layer, a second bonding layer, a second buffer layer and a second outer layer from top to bottom, wherein the base material layer is made of a first polymer, and the first polymer is selected from one or a mixture of more of PVC (polyvinyl chloride), PET (polyethylene glycol terephthalate), PETG (polyethylene glycol terephthalate) and TPU (thermoplastic polyurethane); wherein the first buffer layer and the second buffer layer are respectively and independently selected from one or more of non-woven fabrics and glass fiber mats; wherein the first bonding layer and the second bonding layer are blended membranes of grafted resin and a second polymer, and the second polymer is selected from one or a mixture of more of TPU (thermoplastic polyurethane), EAA (ethylene-acrylic acid copolymer) and PETG (polyethylene terephthalate glycol); wherein the first outer layer and the second outer layer are impregnated with glue.

A protective mask suited for quick regulatory approval and mass production to provide protective use of a wearer includes a mask body having a major portion forming at least one breathing opening configured for holding a filter. The mask body forms a cover contoured to cover, except for the at least one breathing opening, the wearer's mouth and nose when the mask is worn. The mask body further has a flange, wherein a length of the flange extends along a major portion of an edge of the mask body major portion, the flange being configured for pressing against the wearer's face when the mask is worn. The mask body is a material selected from the group consisting of polyethylene terephthalate, polyethylene terephthalate glycol, and poly methyl methacrylate, and combinations thereof.

The invention discloses a conductive polyester fiber and a preparation method and application thereof, and relates to the field of functional fibers.The conductive polyester fiber is of a skin-core structure, a core layer component comprises first polyethylene glycol terephthalate, and a skin layer component comprises second polyethylene glycol terephthalate, a first polyamide elastomer and conductive carbon black masterbatch; the conductive carbon black master batch comprises a second polyamide elastomer and conductive carbon black; the zero-shear viscosity difference value of each polyamide elastomer and each polyethylene glycol terephthalate is controlled, so that the melt viscosity of the polyamide elastomer is lower than that of the polyethylene glycol terephthalate, and the low-viscosity polyamide elastomer is easy to diffuse to the surface of the fiber in the spinning process to drive the conductive carbon black to be enriched on the surface of the fiber; a hard segment in the polyamide elastomer can be crystallized in the stretching and drafting process, so that the conductive carbon black is promoted to be transferred to an amorphous region and enriched; practice shows that the fiber disclosed by the invention not only has excellent conductivity, but also has properties such as lasting stability and excellent mechanical properties.

The invention discloses a method for preparing an aromatic phosphate salt nucleating agent by using nanoscale aluminum chloride, and belongs to the technical field of polymer nucleating agents. 2, 2-methylene-bis (4, 6-di-tert-butylphenol) and phosphorus oxychloride are used as raw materials, the nanoscale aluminum chloride with the particle size of 20-50nm is selected as an inorganic Lewis acid catalyst and acid binding agent, and the aromatic phosphate salt nucleating agent is prepared by using a one-step method. The preparation method comprises the following steps: replacing the traditional organic acid-binding agents such as triethylamine and pyridine, and synthesizing bis [2, 2 '-methylene bis (4, 6-di-tert-butylphenoxy) phosphate] hydroxyl sodium salt by a one-pot method of condensation, hydrolysis for salt removal and neutralization for salt formation; the purity of the product can reach 99% or above through one-time suction filtration, multiple times of washing are not needed, salt-containing wastewater can be recycled as industrial water after being neutralized, and the environmental protection pressure is greatly reduced; the nucleating agent is suitable for modification processing of polymers such as polypropylene (PP), polyethylene glycol terephthalate (PET), polybutylene terephthalate (PBT), polyamide (PA) and the like, and especially meets the strict requirements on the purity and environmental protection property of the nucleating agent in an olefin polymerization process.

A method for converting post-consumer recycled (PCR) flakes of polyethylene terephthalate (PET) to pellets as part of a container recycling procedure, the method including: adding triphenyl phosphite antioxidant to a reactor at a concentration of 0.05 wt.% to 0.15 wt.%; coating the PCR flakes with the triphenyl phosphite in the reactor; and converting the PCR flakes to the pellets in an extruder after coating the PCR flakes with the triphenyl phosphite to reduce yellowing of the pellets during the conversion.

An optically anisotropic polymer thin film includes a crystallizable polymer and an additive configured to interact with the polymer (e.g., via π-π interactions) to facilitate chain alignment and, in some examples, create a higher crystalline content within the polymer thin film. The polymer thin film may be characterized by a bimodal molecular weight distribution where the molecular weight of the additive may be less than approximately 50% of the molecular weight of the crystallizable polymer. Example crystallizable polymers include polyethylene naphthalate, polyethylene terephthalate, polybutylene naphthalate, polybutylene terephthalate, as well as derivatives thereof. Example additives, which may occupy up to approximately 10 wt. % of the polymer thin film, include aromatic ester oligomers, aromatic amide oligomers, and polycyclic aromatic hydrocarbons, for example. The optically anisotropic polymer thin film may be characterized by a refractive index greater than approximately 1.7 and an in-plane birefringence greater than approximately 0.2.

The application relates to the technical field of chemical degradation of waste polyesters, and discloses a titanium-silicon compound catalyst, a preparation method thereof and a method for depolymerizing polyethylene terephthalate. The preparation method of the titanium-silicon compound catalyst comprises the following steps: (1) preparing a solution by reacting a titanium compound, an orthosilicate compound and a solvent with an organic acid solution; and (2) obtaining the titanium-silicon compound catalyst by post-treating the solution. The catalyst has the characteristics of high PET depolymerization rate, low polymerization degree of depolymerization products, high purity of bis(2-hydroxyethyl) terephthalate (BHET) in the depolymerization products and low titanium residual amount in the target product in the PET degradation reaction. The BHET obtained by the method can be directly used for preparing PET polyester products or other high-value-added products, so that the closed-loop recycling of PET is realized.

Provided is a heat-shrinkable polyester film having a high thermal shrinkage in the main shrinkage direction, a high film puncture strength, a high density, and thus an excellent elastic feeling, and a high bag breaking resistance when a bottle falls. A heat-shrinkable polyester film containing 60 mol% or more and 95 mol% or less of terephthalic acid ethylene glycol units in 100 mol% of all ester units, 5 mol% or more and 40 mol% or less of diethylene glycol in 100 mol% of polyol components, and 0 mol% or more and 5 mol% or less of constituent units derived from a monomer component capable of becoming an amorphous component in all polyester resin components, the film having a hot water heat shrinkage rate when immersed in hot water at 90°C for 10 seconds, a film puncture strength, a film density, and a refractive index in the film length direction within a prescribed range.

The application discloses a method for recycling polyester fabric by using an ionic liquid catalyst, and comprises the following steps: providing a recycled polyester fabric; chemically depolymerizing the recycled polyester fabric by using a chemical depolymerization solution to form a depolymerization product containing bis-hydroxyethyl terephthalate (BHET), wherein the chemical depolymerization solution is used to chemically depolymerize the recycled polyester fabric in the presence of a depolymerization catalyst, and the depolymerization catalyst is an ionic liquid catalyst. The method has the advantages of high depolymerization efficiency, high BHET yield and easy recovery of the catalyst.