72 results about "Heat stabilization" patented technology

The invention belongs to the technical field of oilfield chemistry, relates to a thickening agent for a high-temperature-resistant salt-resistant fracturing fluid and a preparation method of the thickening agent, and particularly relates to a thickening agent for a hydrophobic association type fracturing fluid and a preparation method of the thickening agent. The thickening agent for the hydrophobic association type fracturing fluid provided by the invention is prepared by polymerizing the following monomer raw materials: an amide monomer, a carboxylic group-containing monomer, a sulfonic acid monomer and a hydrophobic association monomer. According to the thickening agent for the hydrophobic association type fracturing fluid, a functional group and a hydrophobic group are introduced through molecular design, the thickening agent and an organic zirconium cross-linking agent construct a thermal stable cross-linked network, the temperature resistance and the shear resistance at 150-200 DEG C are higher than those required by a water-based fracturing technology (larger than 50 mPa.s), and the fracturing requirements of deep reservoirs are met.

The invention belongs to the technical field of food additives and new materials, and discloses a thermostable embedding method and application of an alpha-amylase inhibitor, and the method comprises the following steps: respectively adjusting the pH values of an alpha-AL stock solution and an iota-CG stock solution to 6, then mixing the stock solutions according to the mass ratio of alpha-AL to iota-CG of 2: 1, and carrying out heat preservation for 2-3 hours, so as to obtain the thermostable embedding method of the alpha-amylase inhibitor. According to the method disclosed by the invention, the stable ion compound is formed under the condition that the pH is equal to 6 by utilizing the electrostatic interaction and the hydrogen-bond interaction between the negatively charged sulfuric acid group in the iota-carrageenan molecule and the positively charged amino acid residue on the surface of the white kidney bean alpha-amylase inhibitor. According to the compound, stable combination among molecules is achieved by constructing a structured water molecular layer barrier, so that the tolerance of the white kidney bean alpha-amylase inhibitor to heat treatment is remarkably improved, and the defect that the heat stability of the white kidney bean alpha-amylase inhibitor is poor is overcome.

The invention relates to the technical field of high polymer materials, in particular to a preparation process of a bacteriostatic PET film. According to the invention, the defects of poor antibacterial property and poor oil stain resistance of the existing PET film are overcome. The modified PET master batch, the composite antibacterial agent, the nano filler, the modified polydimethylsiloxane, the coupling agent, the flame retardant and the ultraviolet light absorber are subjected to melt blending, extrusion and casting to obtain a film sheet; the film sheet is subjected to biaxial directional stretching, thermal stabilization treatment and hot press polishing treatment, and the antibacterial PET film is obtained. The PET master batch is prepared from pretreated PET resin and PET resin; the composite antibacterial agent comprises a rosemary extract and dodecyl dimethyl benzyl ammonium chloride; the nano filler is prepared from nano silicon dioxide, silver nitrate and the like; the modified polydimethylsiloxane is prepared from hydrogen-containing silicone oil and allyl polyether. The PET film prepared by the invention has strong antibacterial property and good oil stain resistance, and is suitable for coating kitchen ware.

The application discloses a kind of compositions, reagents and its detection method for high-throughput gene sequencing, belong to gene sequencing technical field, the composition includes Tris-HCl buffer 80-120 parts, potassium chloride 40-60 parts, ammonium sulfate 10-20 parts, magnesium chloride 15-25 parts, dNTPs mixed solution 30-50 parts, heat-stable DNA polymerase mutant 8-15 parts, PCR promoter complex 5-12 parts, modified iridium quinoline ketone complex 1-5 parts, glycerol 150-250 parts, Tween-20 1-3 parts, EDTA disodium salt 0.5-2 parts and nuclease-free ultrapure water, by introducing the modified iridium quinoline ketone complex of innovation, effectively solve the technical problems of low amplification efficiency, poor multiplex PCR reaction uniformity and high non-specific amplification background for high GC content, complex secondary structure genomic template, significantly improve the specificity of amplification, uniformity and the quality and reliability of final sequencing data.

The utility model discloses a polycarbonate solution thermostable concentration energy-saving system which comprises a feed delivery pump and a feed concentration tank, the output end of the feed delivery pump is connected with the feed concentration tank through a pipeline, the polycarbonate solution thermostable concentration energy-saving system further comprises a concentration circulating pump and a concentration heater, the bottom end of the feed concentration tank is connected with the concentration circulating pump through a pipeline, and the concentration heater is connected with the feed delivery pump through a pipeline. The concentration circulating pump is connected with a concentration heater through a pipeline, and the concentration heater is connected with the feeding concentration tank through a pipeline; when the dichloromethane solution needs to be concentrated, the PC dichloromethane solution with lower concentration is conveyed into the feeding concentration tank through the feeding conveying pump, and the dichloromethane solution is concentrated and concentrated through the feeding concentration tank, the concentration heater and the concentration circulating pump; and the concentrated dichloromethane solution with higher concentration is conveyed into the double-paddle evaporator by the double-paddle feeding pump, so that the high-concentration dichloromethane solution is obtained, and the concentration efficiency of the dichloromethane solution is improved.

The application relates to the technical field of PET film, and discloses a conductive PET film material for a transparent antenna and a preparation method thereof, wherein the conductive PET film material comprises, from top to bottom, a copper mesh and a PET film; the PET film comprises the following components by weight: 80-90 parts of PET resin, 1-2 parts of a compatilizer, 8-14 parts of a flame retardant, 2-4 parts of an ultraviolet resistance agent and 0.8-1 part of a heat stabilizer; the flame retardant is composed of an organic phosphorus flame retardant and 4-amino-5-imidazole formamide. Through the technical scheme, the problems of poor flame retardance and ultraviolet resistance of the conductive PET film material in the related art are solved.

The application discloses a basic xylanase mutant with improved specific enzyme activity and thermal stability and a preparation method thereof, and belongs to the field of genetic engineering and enzyme engineering. The application provides a basic xylanase mutant M22 through a semi-rational design method, wherein the specific enzyme activity of the mutant M22 is 211 U / mg, which is increased by 181.33% compared with that of a wild type. After 30 min of heat treatment at 75 DEG C, the residual activity of the mutant M22 relative to the wild type is 169.30%, and after treatment at 80 DEG C, 85 DEG C and 90 DEG C, the relative residual activities of the mutant M22 are 153.94%, 127.84% and 115.02% respectively relative to the wild type treated at 75 DEG C for 30 min. The basic xylanase mutant M22 obtained by the application has significantly improved specific enzyme activity and stability compared with the wild type, and has higher application value and potential in industrial production.

A method of producing a carbon-rich material, the method comprising the steps of: a) providing a lignin bead, wherein the lignin bead comprises at least 80 wt% of lignin, based on the dry weight of the lignin bead; b) optionally heating the lignin bead to one or more temperatures in the range of 140 to 270 °C for a period of at least 30 minutes to obtain a heat-stabilized lignin bead; and c) subjecting the optionally heat-stabilized lignin bead to carbonization at one or more temperatures in the range of 300 °C to 1500 °C, wherein the carbonization is carried out for a total time in the range of 30 minutes to 10 hours, so as to obtain a carbon-rich material.

The present invention discloses a high thermal stability and low thermal conductivity zirconium oxide based thermal barrier coating and a preparation method thereof, wherein the raw materials include: 5% to 10% (Y x Sc y Gd 1‑x‑y )2O3, 10%~20% LaPO4, 1%~5% MO z , 8.6%~15.2% RE2O3, the balance is ZrO2; (Y x Sc y Gd 1‑x‑y )2O3, x =0.5~0.75, y =0.05~0.15;MO z In RE2O3, M is one or more of Mg, Ca, and In; in RE2O3, RE is one or more of Er, Sm, Dy, Yb, and Eu. The present invention modifies the components of a zirconia-based thermal barrier coating by doping and optimizes its preparation process, effectively improving the thermal barrier coating's high-temperature stability, thermal shock resistance, and sintering resistance, while reducing its high-temperature thermal conductivity.

The invention discloses a gravimeter temperature control system modeling control method, and relates to the technical field of precise instrument temperature control, and the method comprises the steps: 1, obtaining the real-time running speed of a carrier, the wind speed of an external environment, and the current temperature of a core part of a gravimeter; step 2, feed-forward compensation power is calculated based on the real-time driving speed and the external environment wind speed according to preset dynamic thermal disturbance model parameters; 3, based on the difference value between the current temperature and the preset target temperature, feedback control power is calculated through a preset feedback control algorithm; 4, superposing the feed-forward compensation power and the feedback control power to generate total control power, and outputting the total control power to control the heating actuator. Predictive disturbance compensation is achieved, temperature overshoot is effectively restrained, the thermal stabilization time is remarkably shortened, the operation efficiency is improved, the data quality is improved, the measurement reliability is enhanced, and the method is suitable for large-scale popularization and application. Practicality is high, compatibility is good, and upgrading and reconstruction are easy.

The utility model relates to the technical field of mobile phone shell detection equipment, in particular to equipment for testing a heat stabilizer in PVC (polyvinyl chloride), which comprises an L-shaped plate, a test box is fixedly mounted on the outer wall of one side of the L-shaped plate, and a moving mechanism is arranged at the top of the L-shaped plate. By arranging the mounting mechanism, during use, the PVC block is placed in the protective frame in the mounting box, the cover turning plate covers the PVC block, then the mounting box is mounted in the open slot, and the limiting column is clamped with the mounting box under the action of the spring, so that when the mounting box is fixed and dismounted, only the push block needs to be pushed, the limiting column moves, and the PVC block can be fixed and dismounted. The mounting box is convenient and rapid to mount and dismount, a worker can conveniently sample the PVC block, the dismounting and mounting efficiency is greatly improved, and meanwhile, a heat conduction block is arranged in the turning cover plate, so that heat concentration is facilitated, and the PVC block is conveniently and rapidly heated to a proper temperature.

The utility model discloses a lubricating property testing device for a composite heat stabilizer. The lubricating property testing device comprises a treatment box with an opening in the top, the cover body movably covers the opening end of the treatment box; the stirring assembly is rotationally arranged on the cover body, and the output end of the stirring assembly extends into the treatment box; the heating assembly comprises a mounting groove formed in the side wall of the treatment box, a coil pipe is uniformly arranged in the mounting groove in a surrounding manner, a heating medium is introduced into the coil pipe to heat the to-be-detected liquid in the treatment box, and the stirring assembly is used for stirring the to-be-detected liquid so that the to-be-detected liquid is uniformly heated. According to the device disclosed by the utility model, the coil pipes uniformly arranged in the side wall of the treatment box in a surrounding manner can be used for heating liquid to be detected in the treatment box; the to-be-detected object is stirred through the arranged stirring assembly, so that the to-be-detected object close to and far away from the coil pipe continuously exchanges positions, the to-be-detected object can be uniformly heated, and large deviation of a detection result is avoided.

The invention discloses a modified ETFE material and application thereof, and the modified ETFE material comprises 90-100 parts by mass of ETFE, 0.5-2 parts by mass of an anti-ultraviolet agent, 0.2-0.6 part by mass of an antioxidant, 0.2-1 part by mass of a light stabilizer, 0.2-1 part by mass of a heat stabilizer, 0.5-10 parts by mass of modified ATO and 3-12 parts by mass of a coupling agent. The modified ETFE material provided by the invention has the characteristics of excellent mechanical strength, weather resistance, self-cleaning property and the like, also has excellent infrared barrier property, and is particularly suitable for being applied to preparation of ETFE films for high infrared barrier buildings.

The invention discloses a novel composite phase change heat storage medium and a preparation method thereof, and is characterized in that the novel composite phase change heat storage medium comprises the following substances by weight: 70-75 parts of a phase change energy storage material, 0-8 parts of a heat conduction reinforcing material, 0-15 parts of a water sealing material, 5-10 parts of a modified material, 0-20 parts of a gel material, and 0-10 parts of deionized water. On the one hand, the composite phase change heat storage medium produced through reasonable component composition under specific production and processing conditions has the advantages of being good in heat stability, free of supercooling and phase separation phenomena, large in heat storage density, high in heat conductivity, not prone to volatilization of all component materials and the like;

The invention relates to the technical field of computational toxicology, and discloses a method for calculating combination of perfluorinated and polyfluorinated alkyl compounds and PPARalpha based on a pharmacophore model, which comprises the following steps: acquiring a PFAS initial data set, acquiring a PPARalpha ligand binding domain crystal structure, and optimizing the structure; selecting representative PFAS to carry out molecular docking, and carrying out simulated annealing optimization to obtain an optimal binding posture; then generating a pharmacophore model; the models are screened; performing rigid fitting screening by using a pharmacophore model; carrying out molecular dynamics simulation on the representative hit object, and verifying the stability; protein is extracted by culturing cells in vitro, a thermal displacement experiment is carried out, and the thermal stability effect of PFAS on PPARalpha is verified. According to the method, comprehensive virtual screening of PFAS-PPAR alpha interaction based on pharmacophores is provided, a calculation framework based on protein and compound structures is established, and the method is suitable for environmental pollutant screening and safer chemical design.

The invention discloses a heat-resistant biodegradable film-making material, which is prepared from the following ingredients in parts by mass: 30 to 60 parts of modified polylactic acid, 20 to 35 parts of toughening agents, 10 to 18 parts of multifunctional modifiers, 0.4 to 1.4 parts of nucleating agents, 3 to 5 parts of plasticizers and 0.3 to 0.8 part of bio-based chain extenders. 0.3-10 parts of a composite heat stabilizer and 4-15 parts of an antibacterial agent; the modified polylactic acid is prepared from the following components in parts by mass: 35 to 50 parts of polylactic acid, 5 to 25 parts of polypropylene carbonate, 1 to 6 parts of micromolecular compatilizer and 0.2 to 2 parts of initiator. And the modified polylactic acid improves the biodegradation rate. The heat-resistant biodegradable film-making material disclosed by the invention has excellent temperature resistance, degradability, mechanical strength and toughness, can be widely applied to various industries, and has good application and market prospects. The invention also discloses a production process of the heat-resistant biodegradable film-making material.

Disclosed herein are nanorod productions systems (NPS) useful for the production of biological scalable functionalization-ready nanorods (BSFnano). The nanorods produced are derived from filamentous phage Ff (f1, M13 or fd). The NPS disclosed herein permits efficient biological production of non-infectious, heat-stable isomorphic proteinaceous nanorods comprising modifications allowing site-specific recombinant, chemical and enzymatic attachment of peptide and non-peptide functionalities in an orthogonal manner. Also disclosed are methods of making and using these nanorods, such as in methods of detecting target molecules.

The invention relates to a thermally stable KGF-2 derivative based on artificial intelligence optimization of overall free energy of molecules, and a generation method, device and application thereof. The thermostable KGF-2 derivative is obtained by mutating a phenylalanine residue at the 167th site of wild type KGF-2 into a leucine residue, and / or mutating an alanine residue at the 185th site of the wild type KGF-2 into an isoleucine residue, and removing amino acid residues at the 2nd-68th sites, and the amino acid sequence of the thermostable KGF-2 derivative is as shown in SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO: 8. According to the scheme provided by the invention, free energy simulation calculation can be carried out on the KGF-2 protein molecules to obtain a heat-stable KGF-2 derivative structure with relatively low free energy and even an optimal heat-stable KGF-2 derivative structure, so that the stability of the KGF-2 protein molecules is improved.

The present application relates to photothermal-thermoelectric synergistic material, photothermal-thermoelectric synergistic composite material, preparation method and application thereof, the photothermal-thermoelectric synergistic material includes bismuth selenide-gold composite material, bismuth selenide-gold composite material is hexagonal, gold material is located in the central hexagon.The advantage lies in, gold nanoparticles located in the center of hexagon are used as "heat source core", under the excitation of near infrared light, stable radial temperature gradient is formed with the base bismuth selenide, and then endogenous micro-current is generated based on the Seebeck effect of bismuth selenide, this wireless, non-invasive "photothermal-stable temperature difference-thermoelectric" cascade signal can effectively simulate the bioelectric environment of bone tissue, and the osteogenic differentiation of bone marrow mesenchymal stem cells is significantly promoted;The photothermal-thermoelectric synergistic material of the present application can effectively remove active oxygen, and has good antioxidant property.

The utility model discloses a horizontal pipe evaporation concentrator, which comprises a separator, the separator comprises a hollow shell, a live steam inlet, a condensate water outlet, a material inlet, a concentrated solution outlet and a secondary steam outlet are arranged on the shell, a heater and a spraying assembly are arranged in the shell, the spraying assembly comprises a spraying pipe and a nozzle, the heater comprises a horizontal heating pipe, and the nozzle is arranged in the shell. The plurality of heating pipes are sequentially communicated to form a snakelike heating channel; a feeding pump and a circulating pump; and a condensation assembly. According to the horizontal pipe evaporation concentrator, the spraying assembly and the heater are concentrated in the separator, the compactness of the equipment structure is guaranteed, the occupied space is reduced, feed liquid is sprayed to the heating pipe into which live steam is introduced through the spraying assembly, so that the feed liquid flows down in a film shape under gravity, heat transfer is promoted, meanwhile, it is guaranteed that the feed liquid is heated stably and uniformly, and the efficiency is improved. Therefore, the heating effect is improved.

The invention discloses a self-cleaning antibacterial pipe with a reinforcing rib structure and a preparation method of the self-cleaning antibacterial pipe, and belongs to the technical field of pipes. The self-cleaning antibacterial pipe comprises the following components in parts by weight: 80-120 parts of polyvinyl chloride resin, 3-5 parts of a heat stabilizer, 30-50 parts of self-cleaning antibacterial filler, 40-50 parts of a plasticizer, 2-3 parts of a processing aid and 0.5-1 part of an antioxidant. By adding the self-cleaning antibacterial filler into the pipe, the hydrophobic, antibacterial and mechanical properties of the pipe can be improved, pollutants and bacteria can be effectively prevented from being accumulated and propagated on the surface of the pipe, and the self-cleaning and antibacterial properties of the pipe are remarkably improved, so that the service life is prolonged, and the pipeline is kept sanitary.

The present invention relates to mutated DNA polymerases derived from wild-type Thermus aquaticus (Taq) DNA polymerase, methods for reverse transcription polymerase chain reaction (RT-PCR) using said DNA polymerases, and kits comprising said DNA polymerases.

The invention discloses a preparation method of an ultra-high-temperature-resistant workover fluid capable of protecting an ultra-deep oil and gas reservoir, which is characterized by comprising the following steps of: adding 10 parts by weight of nano SiO2 and 50-350 parts by weight of solvent into a three-mouth reaction bottle provided with a reflux condensing tube, stirring at room temperature to disperse the nano SiO2, heating to 70-90 DEG C, adding 0.5-10 parts by weight of anionic modifier, reacting for 8-24 hours under reflux, and cooling to room temperature to obtain the ultra-high-temperature-resistant workover fluid capable of protecting the ultra-deep oil and gas reservoir. Then centrifuging the reaction system to remove the solvent and the modifier which does not participate in the reaction, and carrying out vacuum drying on the product under heating to obtain nano SiO2-SC containing anions; the preparation method comprises the following steps: pouring 1.0-50 parts of nano SiO2-SC into 1000 parts of a solvent at normal temperature, stirring until the nano SiO2-SC is uniformly dispersed, then pouring 1.0-20 parts of a thickening agent into a nano SiO2-SC system, stirring until the thickening agent is completely dissolved, and then sequentially adding 5.0-120 parts of a viscosity stabilizer, 0.1-10 parts of a bactericide and 0.1-10 parts of a heat stabilizer into the thickening agent solution while stirring, so as to obtain the ultra-deep oil and gas reservoir protection agent capable of protecting the ultra-deep oil and gas reservoir. And the workover fluid can resist the ultrahigh temperature of 180-240 DEG C.

The invention relates to the technical field of preparation of cross-linking agents for fracturing, and discloses a preparation system and method of a cross-linking agent for fracturing, and the system comprises a preparation module which is used for enabling a plurality of raw materials to generate a chemical reaction by adjusting the reaction temperature and the mixing rate to generate the cross-linking agent; the detection module is connected with the preparation module and is used for receiving the cross-linking agent and detecting quality parameters such as the cross-linking viscosity, the initial cross-linking time, the thermal stability temperature and the shearing residue rate of the cross-linking agent; the central control module is connected with the preparation module and the detection module through a data link, and is used for judging the performance grade of the cross-linking agent of the batch based on the cross-linking viscosity peak value detected by the detection module and a preset viscosity parameter interval, and determining the performance grade of the cross-linking agent of the batch according to at least one of the cross-linking viscosity peak value, the thermal stability temperature and the shear residue rate when the performance grade is judged to be a non-superior grade. And parameters of the next batch of preparation process are subjected to self-adaptive adjustment, so that performance grading monitoring and self-adaptive optimization regulation and control in the production process of the cross-linking agent for fracturing are realized.

The invention relates to the technical field of extruders, in particular to a dynamic thermal stability extrusion processing device and method.The dynamic thermal stability extrusion processing device comprises charging barrel units, and at least three charging barrel units are sequentially connected in the axial direction to form a charging barrel structure of an extruder; a heating unit is arranged on the outer wall of each charging barrel unit; a cooling channel is arranged on the inner wall of the charging barrel unit, and the cooling channel is distributed between the heating unit and the inner wall of the charging barrel unit; and a conveying pipeline and a liquid return pipeline of the cooling pipeline are respectively connected with the liquid inlet and the liquid outlet of each cooling channel through valves so as to form a plurality of cooling loops with controllable flow velocity. A heat exchange system composed of a constant-power heating unit and a built-in cooling loop is integrated in each charging barrel unit connected in series in the axial direction, the flow speed of a cooling medium is adjusted through temperature feedback, heating and cooling are decoupled, the heating temperature of each charging barrel unit is independently adjusted in the mode that the flow speed of the cooling medium is changed, and the heating efficiency is improved. And dynamic regulation and control on the extrusion temperature of the molten material are realized.

The embodiment of the invention discloses heat-resistant stable recombinant humanized V-type collagen and a preparation method thereof, relates to the technical field of recombinant protein, and aims to solve the technical problem that existing collagen is difficult to meet application requirements. The preparation method of the heat-resistant and stable recombinant humanized V-type collagen comprises the following steps: respectively obtaining recombinant collagen with gene sequences as shown in SEQ ID No.2, SEQ ID No.4 and SEQ ID No.6, and respectively inserting the recombinant collagen into pPIC9K plasmids to obtain corresponding recombinant plasmids; the recombinant plasmids comprise a recombinant plasmid pPIC9K-ColV alpha 1-1, a recombinant plasmid pPIC9K-ColV alpha 1-2 and a recombinant plasmid pPIC9K-ColV alpha 1-4, and the recombinant plasmid pPIC9K-ColV alpha 1-1, the recombinant plasmid pPIC9K-ColV alpha 1-2 and the The recombinant plasmid is sequentially subjected to electrotransformation treatment, screening treatment, identification treatment and purification treatment, and the recombinant V-type collagen alpha1 is obtained; the recombinant V type collagen alpha1 comprises a recombinant V type collagen alpha1-1, a recombinant V type collagen alpha1-2 and a recombinant V type collagen alpha1-4.

The utility model provides a stability detection device which comprises a thermal stability test tube for placing a sample, a heating device for heating the thermal stability test tube, a hose communicated with the thermal stability test tube, a collecting bottle communicated with the hose, and a pH meter arranged in the collecting bottle, and distilled water for collecting gas is placed in the collecting bottle. According to the stability detection device disclosed by the utility model, hydrogen chloride gas is collected by using distilled water in the collection bottle, so that leakage of the hydrogen chloride gas can be avoided, personal health and safety are protected, the pH value is detected by the pH meter, manual visual monitoring is replaced, the accuracy and reliability of a measurement result are improved, and meanwhile, measurement data can be recorded and analyzed; and subsequent material performance improvement is facilitated.

The invention relates to the technical field of biological monitoring, in particular to a preparation method and application of a blood plate. The preparation method of the blood plate comprises the following steps: adding culture medium components into a culture medium, the culture medium components comprising peptone nitrogen, a yeast extract, reduced glutathione, sodium pyruvate and distilled water; adding blood into the culture medium; adjusting the pH value of the culture medium to be stable; adding a heat-sensitive component and a heat-stable component into the culture medium; and constructing a culture medium low-oxygen mixing environment. Therefore, the shelf life of the blood plate can be prolonged, and the hemolysis phenomenon is reduced.

A polymer composition that comprises from about 20 wt.% to about 70 wt.% of a polymer matrix that includes a polyamide; from about 10 wt.% to about 50 wt.% of inorganic fibers; from about 5 wt.% to about 30 wt.% of a flame retardant system that includes an organophosphorous compound; and from about 0.1 wt.% to about 5 wt.% of a stabilizer system that includes a heat stabilizer is provided. The heat stabilizer includes a copper compound. The polymer composition exhibits an initial tensile strength and an aged tensile strength after exposure to temperature of 200°C for 1,000 hours. The ratio of the aged tensile strength to the initial tensile strength is about 0.5 or more.

The present invention relates to stabilizer compositions for halogen-containing polymers. It has recently been discovered that tin-based heat stabilizers with a bridging alkyl group between two tin centers are effective stabilizers while effectively doubling the molecular weight of the corresponding non-alkyl-bridged stabilizers. Ongoing testing is expected to confirm that the alkyl-bridged stabilizers are much less volatile, resulting in greater retention of the stabilizer in the final article.