1115results about How to "Improve melt strength" patented technology

The present invention concerns a high melt strength propylene polymer or copolymer suitable for manufacturing foams and thermoformed product exhibiting a melt strength of at least 3 g and comprising a high molar mass portion and a low or medium molar mass portion. The polymers are produced by subjecting propylene and optionally other olefins to polymerization in a plurality of polymerization reactors connected in series, employing different amounts of hydrogen as a molar mass modifier in at least two of the reactors, and carrying out the polymerization reaction in the presence of a catalyst system capable of catalyzing the formation of a high molar mass polymerization product having a MFR2 of less than 0.1 g / 10 min and a low or medium molar mass polymerization product having a MFR2 of more than 0.5 g / 10 min.

Advanced structural components comprising a foamed thermoplastic that can be used in virtually any application where wooden components have a use. Such structural components can comprise sized lumber, shaped trim, posts, beams or shaped structural members. An advanced profile composite structural component comprising an exterior capping layer with an interior comprising a foamed thermoplastic can be used in the assembly of fenestration units adapted to residential and commercial structures. Preferably the profile structural component can be used in a window or door assembly. The profile member is adapted for ease of construction of the fenestration units, can be easily installed in a rough opening to framing members, and can be trimmed and adjusted on site. The profile is structurally strong, thermally stable, shrink resistant and will accept and retain the insertion of fasteners such as staples, nails and screws permanently with substantial retention and little or no damage to the units. The profile structural components possess strength that permits the manufacture of a structurally sound fenestration unit from two or more foamed profile members or other conventional members.

Multimodal polyethylene resins having improved stress crack resistance and melt strength rendering them useful for the manufacture of thick-walled pipe are produced in a process wherein the second stage of the process is a copolymerization conducted at a high temperature with a low comonomer to ethylene ratio and a low hydrogen to ethylene ratio.

A protective and / or splint device, for example a distal radial splint device (200), comprises a protective and / or splint member (201) and a spacer member (13). The protective and / or splint member (201) comprises a composite protective and / or splint material and is formable at a forming temperature and is substantially rigid at ambient temperature. The material comprises a polycaprolactone and a ligno-cellulose additive material. The protective and / or splint member (201) comprises a mesh of elements (202), with a plurality of openings (203) through the protective and / or splint member (201). Away from the periphery of the splint member (201), the openings (203) are diamond-shaped. Two border elements (204) extend along the two sides of the periphery of the splint member (201). The three point bending strength to openness ratio of the member is greater than 0.1 and the unidirectional bending strength to openness ratio of the member is greater than 4. This results in a device (200) with sufficient strength, which is breathable with open surfaces, and the volume of material used is optimized. The strength of the member (201) parallel to the longitudinal direction of the arm is greater than the strength parallel too the circumferential direction. At the forming temperature the member (201) is stretchable. The member (201) is rounded between the outer surface of the member (201) and the edges around the openings (203).

Disclosed are blends of aliphatic-aromatic copolyesters with poly(ethylene-co-vinyl acetate) copolymers and shaped articles prepared therefrom. These blends have higher melt strength than the aliphatic-aromatic copolyester alone and exhibit increased melt strength and better processability. In addition, the blends and shaped articles show bio-disintegration and / or biodegradability in a composting environment.

The application relates to a pre-irradiation polypropylene graft copolymer and a preparation method thereof. At present, the exploration of methods for improving surface property remains a research hotspot in the field of modification of polypropylene always. The method comprises the following steps: performing pre-irradiation on polypropylene resin after having constant weight at the temperature of 60 DEG C by using a 60 Co radiation source or a DD-1.2 / 1.0-800 type high-frequency high-pressure electron accelerator in air, keeping the dosage rate at 300Gy / min, keeping the dose at 3-50kGy, adding the pre-radiated polypropylene resin into solution containing N, N'-methylenebis acrylamide, auxiliary monomers and additives, keeping the using amount of the N, N'-methylenebis acrylamide to be 0.5-5% by weight of the weight of polypropylene, performing nitrogen filling and oxygen removal on mixed solution for 30 minutes, then heating to 50-75 DEG C for performing reaction for 6 hours under magnetic stirring, nitrogen production and reflux conditions, washing the polypropylene resin which is filtered out with ethanol-water twice, further extracting with ethanol-water solution for 24 hours, drying at the temperature of 60 DEG C and enabling the weight to be constant. The method is used for preparing the polypropylene graft copolymer.

Substantially isotaclic propylene interpolyraets comprise (A) at least 60 weight percent (wt %) units derived from propylene, and (B) between greater than zero and 40 wt % units derived from ethylene, the propylene interpolyrner further characterized by at least one of the following properties: (1) a ratio of less than 1 measured at interpolyraer number average molecular weight (Mn), (2) a relative compositional drift of less than 50%, arid (3) propylene chain segments having a chain isotacticity triad index of at least 70 mole percent.

The invention is directed to essentially saturated hydrocarbon polymer composition comprising essentially saturated hydrocarbon polymers having A) a backbone chain, B) a plurality of essentially hydrocarbyl sidechains connected to A), said sidechains each having a number-average molecular weight of from 2500 Daltons to 125,000 Daltons and a MWD by SEC of 1.0-3.5; and having A) a Newtonian limiting viscosity (eta0) at 190° C. at least 50% greater than that of a linear olefinic polymer of the same chemical composition and weight average molecular weight, preferably at least twice as great as that of said linear polymer, B) a ratio of the rubbery plateau modulus at 190° C. to that of a linear polymer of the same chemical composition less than 0.5, preferably <0.3, C) a ratio of the Newtonian limiting viscosity (eta0) to the absolute value of the complex viscosity in oscillatory shear (eta*)at 100 rad / sec at 190° C. of at least 5, and D) a ratio of the extensional viscosity measured at a strain rate of 1 sec-1, 190° C., and time=3 sec (i.e., a strain of 3) to that predicted by linear viscoelasticity at the same temperature and time of 2 or greater. Ethylene-butene prepared by anionic polymerization and hydrogenation illustrate and ethylene-hexene copolymers prepared by coordination polymerization illustrate the invention. The invention polymers exhibit improved processing characteristics in that the shear thinning behavior closely approaches that of ideal polymers and exhibit improved strain thickening.

The present invention provides a process for preparing high melt strength propylene polymer by direct polymerization, comprising that a propylene polymer with wide molecular weight distribution and containing “very high molecular weight fraction” can be prepared by controlling the species and ratios of the external electron donors in the Ziegler-Natta catalyst system at different reaction stages according to the requirment for different molecular weight fractions in the different propylene polymerization stage of the series operation, and said polymer has excellent mechnical properties, especially with very high melt strength. The present invention also provides a propylene homopolymer with high melt strength, comprising the following features: (1) the MFR is 0.2-10 g / 10 min at 230° C. with a load of 2.16 kg; (2) the molecular weight distribution Mw / Mn is 6-20; (3) the content of the fraction with a molecular weight higher than 5,000,000 is higher than or equal to 0.8 wt %; (4) Mz+1 / Mn is higher than or equal to 70. Said homopolymer can be used in the preparation of foam products, thermoforming products, biaxial stretching films, blown films and blow-molded products.

Branched crystalline polypropylene compositions and methods for the preparation of branched crystalline polypropylene compositions are provided. For example, described herein is a process of preparing a branched crystalline polypropylene composition that includes combining two or more different metallocene catalyst compounds with a polymerization medium that includes propylene, for a time sufficient to provide branched crystalline polypropylene that has from 0.0 wt % to 2.0 wt % ethylene and a heat of fusion of 70 J / g or more.

The invention relates to a modified polylactic acid composite material suitable for 3D printing and a preparation method of the composite material. The modified polylactic acid composite material suitable for 3D printing is prepared from the following raw materials in percentage by weight: 80-90% of polylactic acid, 6-10% of a flexibilizer, 1-2% of a nucleating agent, 1-3% of a dispersing agent, 1-2% of a chain extender and 1-3% of a compatilizer. The preparation method of the modified polylactic acid composite material suitable for 3D printing comprises the following steps: mixing the raw materials by virtue of a high-speed mixer, and extruding and drawing by using a single-screw extruder. Compared with the prior art, the composite material prepared by the method is good in flexibility; meanwhile, the impact strength, the heat resistance and the breakage elongation can be greatly improved; the printing is smooth when the composite material is used for 3D printing; the finished product has the advantages of smooth surface, beautiful and shapely appearance and stable size.

The invention discloses a plant fiber-reinforced polylactic acid foam material, which is prepared from the following components: 20 to 95 percent of polylactic acid, 1 to 60 percent of plant fiber powder, 1 to 5 percent of foaming agent, 1 to 5 percent of nucleating agent, 1 to 5 percent of antioxidant and 1 to 5 percent of bulking agent. The invention also discloses a preparation method for the material. The foam material has the advantages of low apparent density, biodegradability, no environmental pollution, capacity of replacing polyolefin foam materials, wide application in the fields of heat insulation, buffer and packaging, simple preparation process and high production efficiency.

Disclosed are blends of aliphatic-aromatic copolyesters with poly(ethylene-co-vinyl acetate) copolymers and shaped articles prepared therefrom. These blends have higher melt strength than the aliphatic-aromatic copolyester alone and exhibit increased melt strength and better processability. In addition, the blends and shaped articles show bio-disintegration and / or biodegradability in a composting environment.

The invention relates to a preparation method of biodegradable polyester, and specifically relates to a preparation method of biodegradable polyester with a low carboxyl end group content. The method comprises esterification reactions and condensation and polymerization reactions: after the esterification reaction, polycyclic oxy-compounds are directly added into the reaction products to carry out reactions, and the reaction products are subjected to carry out condensation and polymerization reactions so as to obtain the biodegradable polyester with a low carboxyl end group content, wherein the carboxyl end group content is 5 to 20 mmol / kg. The invention aims to solve the problem of high carboxyl end group content in biodegradable polyesters, namely aliphatic polyester / copolymer and aliphatic-aromatic copolyester materials. The method provided by the invention reduces the carboxyl end group content in the materials, improves the flux strength, shortens the reaction time, obtains a polyester material with a good color (low b value), improves the anti-aging ability of the biodegradable polyester material, and prolongs the service life of the biodegradable polyester material. The preparation method has the advantages of controllable reaction conditions, low cost, and suitability for industrial production.

The invention discloses a degradable polylactic acid diblock copolymer, a preparation method and application to modified polylactic acid, solving the problems of instable performance, high preparation cost and unsuitability for industrialized continuous production of modified polylactic resin in the prior art. The preparation method of the degradable polylactic acid diblock copolymer comprises the following steps of: adding dried and dewatered polylactic acid A with an end group being hydroxy into a reaction device under the protection of an inert atmosphere, adding diisocyanate B, heating to 185-190 DEG C, reacting with stirring for 5-8h, adding degradable high polymer C containing hydroxy, reacting with stirring for 1-2h at the temperature of 185-190 DEG C, adding the diisocyanate B, and reacting at the temperature of 185-190 DEG C until the stirring is difficult to obtain the degradable polylactic acid diblock copolymer. The degradable polylactic acid diblock copolymer disclosed by the invention is good in compatibility with the polylactic resin, is used for modifying the polylactic resin, is capable of remarkably improving processing property and mechanical property of the polylactic resin, and has the elongation at break reaching 60 percent.