365 results about "Intrinsic viscosity" patented technology

The invention provides a superfine denier profiled polyester staple fiber and a preparation method thereof.The preparation method includes the steps of raw material pretreatment, melt spinning, nascent filament treatment, heat setting and curling, oiling and cutting off and the like, polyester chips have high intrinsic viscosity and melting point, and under the action of six-zone temperature control, a high-hole-density spinneret plate and a high draft multiple, the polyester chips are subjected to melt spinning, so that the polyester chips are prepared into the superfine denier profiled polyester staple fiber. The superfine, special-shaped and hollow polyester staple fibers are prepared. The obtained polyester staple fiber has good breaking strength, rebound resilience and a low-defect structure, the bulkiness, flexibility and structural consistency of the fiber are remarkably improved, the environment and process limitation of a traditional sea-island fiber alkali stripping method is broken through, and the polyester staple fiber is suitable for the fields of high-end filling, plush imitation, non-woven materials and the like.

The invention relates to a PC / PET alloy material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The PC / PET alloy material disclosed by the invention is prepared from the following components in parts by weight: 38 to 57 parts of PC resin, 18 to 32 parts of PET resin, 9 to 16 parts of talcum powder, 1.5 to 8 parts of toughening agent and 0.05 to 0.35 part of ester exchange inhibitor, the pH value of the talcum powder is less than 9, and the D50 particle size is 2-3 [mu] m; the intrinsic viscosity of the PET resin is 0.7 to 0.9 dL / g; the ester exchange inhibitor comprises at least one of sodium pyrophosphate and disodium dihydrogen pyrophosphate. The PC resin and the medium-viscosity PET resin are compounded, and the talcum powder with small pH value and small particle size is selected, so that the degradation of PC can be reduced, the shear heat of a PC / PET system is reduced, and good impact performance and good appearance after heat retention are realized.

The invention discloses a process method for preparing a multi-component aramid copolymer through continuous polymerization, and relates to the technical field of high polymer material preparation, and the process method comprises the following steps: S1, preparing a premix: weighing one or more aromatic diamine monomers according to a certain mass ratio, dissolving the aromatic diamine monomers in an amide solvent or a solvent compounded by amides and hydrotropy salt, and stirring to obtain the premix; uniformly stirring and dissolving in a reaction kettle under the protection of a nitrogen environment to form a premix; s2, low-temperature pre-polycondensation reaction; s3, low-temperature polycondensation reaction; s4, post-treatment: neutralizing, washing and drying the multi-element aramid polymer powder obtained in S3, and removing the solvent and the hydrotropy salt to obtain pure and uniform-particle brown yellow powder; or the obtained polymerization stock solution is neutralized, defoamed and filtered to obtain a spinning stock solution, the intrinsic viscosity of the processed brown yellow powder or spinning stock solution is larger than 4.5 dL / g, the polymer powder / polymerization solution can be used for preparing the multi-element aramid fiber through spinning, and the method effectively reduces the industrial production cost of the multi-element cyclic aramid fiber and improves the production efficiency.

The present disclosure relates to a melt-spun high-viscosity PET / low-viscosity PET two-component elastic fiber and a preparation method therefor. The preparation method adopts a six-reactor process. Terephthalic acid and ethylene glycol undergo first and second esterification reactions and first and second prepolymerization reactions, and an obtained ethylene terephthalate prepolymer is respectively introduced into a high-viscosity final polymerization reactor and a low-viscosity final polymerization reactor for polymerization reaction to obtain a high-viscosity melt and a low-viscosity melt, respectively, and then the two melts are spun together. The viscosity of the high-viscosity component can be significantly improved, and a wider range of viscosity difference between the high-viscosity and low-viscosity polyester melts can be obtained. A difference between the intrinsic viscosity of the high-viscosity melt and the intrinsic viscosity of the low-viscosity melt is 0.100-0.550; the prepared PET / PET two-component elastic fiber has high quality and high crimp shrinkage rate.

The present invention belongs to the field of polyester industrial filaments, and relates to methods for preparing a softening flame retardant and preparing a high-strength flexible flame-retardant polyester industrial yarn. The softening flame retardant is silicon dioxide which is surface grafted with polydimethylsiloxane; a preparation method therefor comprises subjecting silicon dioxide and hydroxyl-terminated polydimethylsiloxane to a grafting reaction to obtain the softening flame retardant; and the use thereof is to use the softening flame retardant and low-viscosity polyester chips as main raw materials to prepare a softening flame-retardant polyester masterbatch, which is then subjected to melt-blending and spinning together with high-viscosity polyester chips, so as to prepare a high-strength flexible flame-retardant polyester industrial yarn, wherein the intrinsic viscosity of the low-viscosity polyester chips is 0.65-0.68 dL / g, and the intrinsic viscosity of the high-viscosity polyester chips is 1.05-1.20 dL / g. The preparation methods of the present invention are simple; the flexibility and flame retardancy of the polyester industrial yarn can both be improved after the prepared softening flame retardant is added to the polyester industrial yarn as an additive; and the obtained high-strength flexible flame-retardant polyester industrial yarn has good performance.

A method for producing a polyester film, comprising mixing a recovered polyester resin (A) and a polyester resin (B) comprising an aluminum compound and a phosphorus compound, the polyester resin (A) satisfying the following (1) to (3): (1) the polyester resin (A) comprises at least one element selected from antimony, titanium, and germanium; (2) the polyester resin (A) has a total content of antimony, titanium, and germanium elements of 2 to 500 ppm by mass; and (3) the polyester resin (A) has an intrinsic viscosity of 0.5 to 0.8 dl / g.

The invention discloses a method for preparing high molecular weight thermotropic liquid crystal polyester through melt coupling solid phase polycondensation. The method comprises the following steps: mixing p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and a catalyst 1-methylimidazole according to a specific molar ratio of (70-75): (25-30) to synthesize a liquid crystal polyester prepolymer with specific logarithmic viscosity; the preparation method comprises the following steps: crushing and drying a liquid crystal polyester prepolymer, placing prepolymer particles in a solid phase polycondensation device, accurately controlling the time and temperature of the polycondensation reaction, carrying out heating reaction in a nitrogen atmosphere to obtain high molecular weight thermotropic liquid crystal polyester, taking out the high molecular weight liquid crystal polyester, and carrying out viscosity test. In the preparation process of the prepolymer, the prepolymer with proper logarithmic viscosity can be effectively prepared by controlling the reaction temperature and time, so that the controllable preparation of the polymer is realized; the solid-phase polycondensation time required for obtaining the high-molecular-weight polymer is shortened by crushing the prepolymer into particles with different diameters, so that the solid-phase polycondensation efficiency is improved.

The invention relates to the technical field of chemical fibers, in particular to a low-melting-point polyester FDY (fully drawn yarn) preparation process which comprises the following steps: preparing raw materials, selecting polyester chips and a low-molecular-weight polyester copolymer, mixing the polyester chips and the low-molecular-weight polyester copolymer according to a ratio, melting and blending the polyester chips and the low-molecular-weight polyester copolymer with the additive amount of 5-8wt% and the intrinsic viscosity of 0.65-0.70 dL / g, and performing extrusion molding to obtain the low-melting-point polyester FDY. And putting the mixed raw materials into a screw extruder, and carrying out melt blending and spinning treatment at 250-260 DEG C. According to the low-melting-point polyester FDY and the preparation method thereof disclosed by the invention, a component regulation end is arranged, so that a synergistic effect mechanism of a polyester matrix and a low-melting-point copolymer is accurately matched in a preparation process of the low-melting-point polyester FDY, and the uniformity of melt components is ensured; meanwhile, the copolymerization structure design directivity acts on molecular chain regularity regulation and control, thermal stability fluctuation in the spinning process is inhibited in real time, it is guaranteed that the continuous forming capacity of fibers is maintained under the high-speed spinning condition, and the stability of a production line is improved.

The present invention relates to a sustained release microsphere and a sustained release preparation comprising a GLP-1 receptor agonist or a pharmaceutically acceptable salt thereof. The present invention relates to a sustained release formulation, and more specifically, to a sustained release formulation comprising a GLP-1 receptor agonist or a pharmaceutically acceptable salt thereof, the sustained-release microparticles comprise a GLP-1 receptor agonist or a pharmaceutically acceptable salt thereof, one kind of low-viscosity polylactic acid-glycolic acid copolymer (PLGA) having an intrinsic viscosity of 0.14 dL / g to 0.24 dL / g, and two or more kinds of high-viscosity polylactic acid-glycolic acid copolymers having an intrinsic viscosity of 0.32 dL / g to 0.60 dL / g, so that the sustained-release microparticles do not have the problems of excessive release and delayed release in the initial stage of a drug. Long-term sustained release can be realized, and the bioavailability is excellent.

The invention discloses a composite catalyst for synthesizing polyester as well as a preparation method and application thereof, and relates to the technical field of catalysts. According to the technical scheme, the method comprises the following steps: in a nitrogen atmosphere, mixing a first metal catalyst, a slow release agent and an organic solvent, reacting at 130-150 DEG C for 1-3 hours, and distilling to separate by-products to obtain a reaction product; and adding a second metal catalyst and an activity regulator into the reaction product, reacting at 130-150 DEG C for 1-3 hours, and distilling to separate by-products, thereby obtaining the composite catalyst for synthesizing polyester. The composite catalyst for synthesizing polyester has good compatibility with water, ethylene glycol or PET oligomer, and has the characteristic of controllable catalytic activity compared with a traditional titanium catalyst. When the composite catalyst is applied to synthesis of polyester, the composite catalyst has the characteristics of few side reactions and fast ester exchange reaction, and the obtained polyester product has the advantages of high intrinsic viscosity and good product hue.

The invention relates to the technical field of high polymer material processing and process detection, and discloses an ultrasonic transmission-based regenerated polyester homogenization kettle on-line viscosity monitoring method, which comprises the following steps of: constructing a multi-channel ultrasonic transmission sensing array in a homogenization kettle to obtain melt acoustic propagation characteristics in real time; the intrinsic viscosity is dynamically analyzed based on a sound velocity-attenuation joint inversion model; viscosity data and stirring, heating and other execution units are subjected to closed-loop linkage, and technological parameters are regulated and controlled in a graded mode according to the deviation and the duration. According to the method, non-contact, real-time and accurate monitoring and active regulation and control of the viscosity of the regenerated polyester melt are realized, and the batch consistency of products and the intelligent level of production are remarkably improved.

The preparation method comprises the following steps: sequentially carrying out esterification reaction and polycondensation reaction on terephthalic acid, ethylene glycol, equol or a derivative thereof in the presence of the catalyst to generate the modified polyester, wherein the catalyst is prepared by enabling antimony trioxide, stannous octoate, tetrabutyl titanate and triphenyl phosphite to react in a solvent at the temperature of 100 DEG C or above; the modified polyester prepared by the method has relatively high intrinsic viscosity and fracture tensile strength, can meet the application requirements of special high polymer materials, and solves the problem that the application of semi-biomass PET copolyester in the field of special high polymer materials is limited in the prior art.

The invention relates to the technical field of polyester yarns, in particular to a high-strength polyester yarn and a preparation method thereof.The method comprises the steps that PET slices with the intrinsic viscosity of 0.85-1.00 dL / g are subjected to melt spinning and cooled through circular blowing to obtain nascent fibers, the nascent fibers are subjected to surface activating treatment through low-temperature plasma or esterase bio-enzyme, and the high-strength polyester yarn is obtained; the preparation method comprises the following steps: firstly, activating fibers, then carrying out graft copolymerization reaction on the activated fibers and graft monomer solutions such as fluorinated acrylate and acrylic acid, and finally, cleaning, drying, carrying out thermal network and winding on the composite fibers, so that the prepared polyester yarn has the breaking strength of more than or equal to 7.7 g / D, the dry heat shrinkage rate of less than or equal to 3.5% and the shrinkage tension of less than or equal to 0.03 g / D, has the high functional characteristics of lasting super-hydrophobicity, antibacterial property and the like, is excellent in washing resistance, and is suitable for industrial production. The problem that functionalization is difficult due to surface inertia of the polyester fiber is solved, and the mechanical property and the surface characteristic of the polyester fiber are comprehensively improved.

This disclosure relates to ethylene interpolymer products comprising a Melt Flow-Intrinsic Viscosity Index value, MFIVI, of from ≥0.05 to ≤0.80; a first derivative of a melt flow distribution function, formula (I) at a loading of 4000 g, of from ≥−1.85 to ≤−1.51; a sum of unsaturation, SUMU, from ≥0.047 to ≤0.100 unsaturations per 100 carbon atoms; and a residual QC catalytic metal of from ≥0.03 to ≤5 ppm of hafnium. Ethylene interpolymer products comprise at least two ethylene interpolymers. Ethylene interpolymer products are characterized by a melt index (I2) from 0.3 to 500 dg / minute, a density from 0.855 to 0.975 g / cc and from 0 to 25 mole percent of one or more a-olefins. Ethylene interpolymer products have polydispersity, Mw / Mn, from 1.7 to 25; and CDBI50 values from 1% to 98%. These ethylene interpolymer products have utility in flexible as well as rigid applications.

This invention discloses a method for preparing poly(glycolic acid-caprolactone) copolymers, belonging to the field of polymer synthesis technology. The method includes: prepolymerizing ε-caprolactone with a catalyst and initiator at 40–60°C below the melting point of glycolide under an inert atmosphere; adding glycolide and heating to 160–220°C for the main polymerization reaction; after the reaction, dissolving, precipitating, washing, and drying to obtain the poly(glycolic acid-caprolactone) copolymer. This invention utilizes the physical difference in melting points between glycolide and ε-caprolactone, preferentially prepolymerizing ε-caprolactone at a temperature below the melting point of glycolide, resulting in a higher conversion rate of ε-caprolactone than glycolide in the initial stage of the main polymerization, effectively controlling the copolymerization reaction pathway. Using this method, copolymers with a weight-average molecular weight of not less than 100,000 Da and an intrinsic viscosity of 1.8–3.5 dL / g can be obtained within a wide range of glycolide molar content from 15% to 85%, and the degradation behavior is stable and controllable. This method is simple and requires no special equipment or chain extender, making it suitable for the large-scale preparation of medical materials such as absorbable sutures and tissue repair scaffolds.

This application provides a method and device for determining the health of a silk artifact. The method includes: obtaining the initial brightness, initial intrinsic viscosity, parameter values of multiple environmental parameters, cumulative illumination time, and cumulative exposure time of the silk artifact; determining the brightness change of the silk artifact to a target prediction time using a brightness change function model based on the cumulative illumination time, cumulative exposure time, and parameter values of the multiple environmental parameters; determining the intrinsic viscosity change of the silk artifact to a target prediction time using an intrinsic viscosity change function model based on the cumulative illumination time, cumulative exposure time, and parameter values of the multiple environmental parameters; and determining the health of the silk artifact at the target prediction time based on the initial brightness, initial intrinsic viscosity, brightness change, and intrinsic viscosity change. This solution can relatively accurately predict the health of a silk artifact at a specific time, reducing the complexity of determining the health of the silk artifact.

Provided is a polyethylene powder that completes swelling in a short time, offers a uniform appearance or shape of a molded article, and produces a molded article with smooth surface even by high-speed molding.The polyethylene powder satisfies (requirements 1 and 2). (Requirement 1): an intrinsic viscosity (IV) is 1.5 dL / g or more and 34.0 dL / g or less, and (requirement 2): a ratio γ0 / γ1 of an elastic limit strain γ0 at a swelling time t (h) of 0 hours to an elastic limit strain γ1 at a swelling time t (h) of 1 hour is 0.80 or more and 0.95 or less, wherein the ratio is obtained from a strain dependence test.

The present application relates to the technical field of detection, and particularly relates to a method for measuring intrinsic viscosity of rubber by using chlorobenzene solution, comprising the following steps: obtaining initial mass of insoluble polymer sample; filtering solution of the sample to obtain mass of insoluble substance intercepted by filter medium; cleaning container of the sample of the solution and collecting cleaning liquid to obtain mass of container residue; determining real sol mass based on the mass of the residue, the mass of the insoluble substance and the mass of the container residue; and determining concentration of the solution based on the real sol mass and volume of the solution. The present application effectively solves the technical problem of large error in measuring intrinsic viscosity by using tetrahydrofuran solvent, and simultaneously provides an alternative scheme for evaluating quality of natural rubber.

The present invention addresses the problem of providing a polyester film which has excellent material recyclability. A polyester film according to the present invention comprises: a base material film that contains a polyester resin; and a functional layer that is provided on at least one surface of the base material film. The self-hydrolysis resistance parameter SHS represented by formula 1 satisfies 1.50 or less.　Formula 1: SHS = 0.245([IV]f -1.47 - [IV]i -1.47) (In the formula, [IV]i represents the limiting viscosity IV of the polyester film. [IV]f represents the limiting viscosity IV after heat-treating the polyester film at 300°C for 2 hours in a nitrogen atmosphere.)

Process and apparatus for processing of polycondensates, in particular for recycling processing of contaminated polycondensates, comprising the following processing steps: a) initially charging the polycondensates / materials to be processed, in particular in a container, b) at least partially, especially completely, melting the polycondensates, in particular by extruding in an extruder, and preparing a polymer melt, c) mixing the polymer melt, d) cooling the polymer melt, e) treating the mixed and cooled polymer melt in a melt reactor, in particular for polycondensation / postcondensation, to increase the intrinsic viscosity and / or to purify the polymer melt.

The present invention relates to seed particles of polyamide powder (PA), which consist of: - a polyamide core with a d50 value ranging from 15 to 60 μm, and - a polyamide shell, characterized in that the shell has a higher intrinsic viscosity in solution and a higher melting point than the core.

A method for preventing adhesion of and clogging with a mineral raw material by performing at least any of transfer and treatment of a raw material mixture in which a mineral raw material has been brought into contact with a cationic w / o emulsion polymer in a transfer and treatment facility and preventing adhesion of and clogging with the mineral raw material in the transfer and treatment facility, wherein the cationic w / o emulsion polymer has an intrinsic viscosity of 10.0 dL / g or less.

The invention belongs to the technical field of spinning, and relates to a method for reducing PET melt spinning pressure on the premise of low damage to fiber performance. The silicone with specific content, specific structure and specific molecular weight is introduced into the PET melt in the form of master batch, so that the pressure of a spinning component can be remarkably reduced, and the intrinsic viscosity of the PET body and the mechanical property of the fiber can be maintained as much as possible on the premise of not changing the main chain structure of the PET, not changing the molecular weight of the PET body and not depending on the dispersion of nano particles.

A polyester composition and a product thereof are provided. The polyester composition includes a resin (A), a fiber reinforcement (B), an organic reinforcement (C), a crystal nucleating agent (D), and a toughening agent (E). An intrinsic viscosity of the resin (A) is 0.6 dL / g to 0.85 dL / g.

The invention belongs to the technical field of high polymer material synthesis, and relates to application of 1-butyl-2, 3-dimethylimidazole trifluoromethanesulfonate as a cocatalyst in direct esterification synthesis of PET (Polyethylene Terephthalate), which comprises the following steps: adding purified terephthalic acid, ethylene glycol, 1-butyl-2, 3-dimethylimidazole trifluoromethanesulfonate and a polycondensation catalyst into a reaction kettle; the method comprises the following steps: replacing air in a reaction kettle with inert gas, controlling the pressure in the reaction kettle to be 0.20-0.24 MPa, heating to 222-227 DEG C, stirring to carry out esterification reaction for 80-110 minutes, releasing the pressure to normal pressure, heating to 260-280 DEG C, and carrying out polycondensation reaction under a negative pressure condition to obtain a PET product after the polycondensation reaction is finished, and the PET product has the intrinsic viscosity of 0.70-0.75 dL / g, the terminal carboxyl group content of less than or equal to 50 mmol / kg, the L value of more than or equal to 60 and the b value of less than or equal to 4.5. The method provided by the invention solves the problem of high energy consumption in traditional PET synthesis, improves the esterification reaction rate, inhibits side reactions, reduces the production cost, and improves the quality of PET products.

The invention discloses a cross-linked toughened modified low-temperature hot-melt adhesive polyester chip and a preparation method thereof. A semi-continuous production synthesis device is used. During the esterification reaction process, different diols, triols and dibasic acids are introduced in three steps. Each esterification step is completed in stages by controlling the addition sequence and the reaction temperature, ensuring that the replaced alcohol and acid can generate specific esterification segments, thereby achieving the purpose of cross-linking and toughening modification. After the esterification is completed, the esterified product is introduced into a polycondensation reaction device through a 15-25 μm filter and nitrogen pressurization. The polycondensation reaction temperature, vacuum degree, stirring rate and final temperature are controlled to achieve preset values ​​before discharging. The intrinsic viscosity is ensured to be 0.450±0.005 dl / g and the melt index is achieved to be above 65 g / 10 min (160° C. / 2160 g). The high-temperature melt passes through a casting head, an underwater pelletizing device and a drying device, finally obtaining the cross-linked toughened modified low-temperature hot-melt adhesive polyester chip.

The present invention relates to a process for recycling a stream of polyester waste material by depolymerizing polyesters by alcoholysis to a liquid mixture comprising oligomeric esters having 5 to 20 subunits, and continuously feeding said liquid mixture of oligomeric esters to a reactor in which said liquid mixture is present in combination with a gas headspace, said reactor having means for increasing the interface between said liquid mixture and said gas headspace by at least 5 times relative to a horizontal cross section of said reactor, and maintaining a pressure in said headspace of less than 20 mbar, whereby said oligomeric esters are repolymerized to polyesters having an intrinsic viscosity of at least 0.3 dL / g during a residence time of the mixture in said reactor of less than 120 minutes. The present invention also relates to a system for applying this process.

The invention discloses a preparation method of halogen-free flame-retardant PET polyester chips, and belongs to the technical field of polyester materials. The preparation method of the PET polyester chip comprises the following steps: adding terephthalic acid, ethylene glycol, tetrabutyl titanate and 50% of a coagulation blocking auxiliary agent into a reaction kettle, heating, and carrying out stirring reaction at normal pressure to obtain an esterification system; vacuumizing and heating the esterification system, and carrying out condensation polymerization; at the initial stage of polycondensation, adding the rest 50% of the condensation blocking auxiliary agent; and in the middle stage of polycondensation, adding a modified organic flame retardant, phenyl polysiloxane microspheres, an antioxidant and a stabilizer, continuously reacting until the intrinsic viscosity is 0.7-0.8 dL / g, discharging, casting a strip and slicing to prepare the halogen-free flame-retardant PET polyester chip. The PET polyester chip prepared by the invention has high flame retardant property and does not contain halogen elements.

Heterophasic propylene compositions with improved stiffness and impact The present invention relates to a heterophasic propylene composition (terHECO) comprising a matrix phase of a propylene / ethylene / 1-butene terpolymer and a dispersed phase of propylene-ethylene elastomer, wherein the heterophasic propylene composition (terHECO) has - a melt flow rate MFR2, as determined in accordance with ISO1133 at 230 °C under 2.16 kg, of from 0.1 to 10.0 g / 10 min; - an ethylene content, as determined by quantitative 13C-NMR spectroscopic analysis, of from 5.0 to 25.0 wt.-%; - a melting temperature Tm, as determined in accordance with ISO 11357 / part 3 / method C2, of from 125 to 145 °C; - a xylene cold soluble (XCS) fraction, as determined in accordance with ISO 16152 at 25 °C, of from 10 to 55 wt.-%; - an ethylene content of the xylene cold soluble (XCS) fraction (C2(XCS)), as determined by quantitative 13C-NMR spectroscopic analysis, of from 35 to 80 wt.-%; - an intrinsic viscosity of the xylene cold soluble (XCS) fraction (iV(XCS)), as determined in accordance with ISO 1628-1&3, of from 0.5 to 5.0 dl / g.

A gas separation membrane, a preparation method therefor, and the use thereof in which the gas separation membrane comprises 60-100 mol % of a monomeric unit derived from α,β,β-trifluorostyrene, and has an intrinsic viscosity of 0.5-5.0 dL / g and a tensile strength of at least 50 MPa. According to the GB / T 1038-2000 test method test, the permeability coefficient of hydrogen is at least 100 barrer.