摘要:
A polyethylene having improved rheological properties is disclosed. The polyethylene has a melt index (MI2) from about 0.01 dg/min to about 50 dg/min and a melt strength (&eegr;) that satisfies MI2×&eegr;≧3.5. A process for making the polyethylene is also disclosed. The process uses an azaborolinyl-containing single-site catalyst in the presence of hydrogen, where the hydrogen consumption is controlled to be less than 30%.
摘要:
The present invention provides an ethylene copolymer resin that has unique melt elastic properties not observed in ethylene copolymers heretofore known. Specifically, the ethylene copolymer resin of the present invention when in pelletized form has a reduction in melt elasticity (ER) of 10% or more to a final value of 1.0 or less upon rheometric low shear modification or solution dissolution. Moreover, the resin of the present invention when in reactor-made form exhibits at least a partially reversible increase of 10% or more in ER when pelletizing the same. An ethylene polymerization catalyst, a process of preparing the ethylene copolymer resin and a high-impact film are also provided herein.
摘要:
The present invention provides an ethylene copolymer resin that has unique melt elastic properties not observed in ethylene copolymers heretofore known. Specifically, the ethylene copolymer resin of the present invention when in pelletized form has a reduction in melt elasticity (ER) of 10% or more to a final value of 1.0 or less upon rheometric low shear modification or solution dissolution. Moreover, the resin of the present invention when in reactor-made form exhibits at least a partially reversible increase of 10% or more in ER when pelletizing the same. An ethylene polymerization catalyst, a process of preparing the ethylene copolymer resin and a high-impact film are also provided herein.
摘要:
Disclosed is a method for making LLDPE grades having different xylene solubles or hexane extractables with the same Ziegler-Natta catalyst by varying the amount of alkylaluminum used for polymerization. The method comprises copolymerizing ethylene with a C3-10 α-olefin in the presence of a Ziegler-Natta catalyst, an alkylaluminum, and an electron donor; determining the dependency of the xylene solubles or hexane extractables on the alkylaluminum/electron donor ratio; and adjusting the alkylaluminum/electron donor ratio to achieve a desired xylene solubles or hexane extractables.
摘要:
A process for polymerizing ethylene is disclosed. The polymerization is performed in the presence of a Ziegler-Natta catalyst system in two slurry reaction zones. Most of the polyethylene (70-95 wt. %) is produced in one of the zones, while a smaller fraction is produced in the other zone. The ratio of the weight average molecular weight of the smaller fraction to that of the larger fraction is greater than 8:1. The resulting polyethylene blend, which should have both high melt strength and high extrudate swell, will be useful for blow-molding applications.
摘要:
Resins comprising a relatively high-density, low-molecular-weight polyethylene component and a relatively low-density, high-molecular-weight ethylene copolymer component and methods of making the resins are disclosed. The rheological polydispersity of the high-density component exceeds that of either the resin or the low-density component. The resins are valuable for making films, sheets, coatings, pipes, fibers, and molded articles having a favorable balance of good stiffness and excellent environmental stress crack resistance.
摘要:
A process for improving the melt characteristics of polyethylene resins is provided. The process involves contacting a polyethylene resin powder with a low level of free radical initiator at a temperature below the melting point of the resin.
摘要:
A very low density polyethylene (VLDPE) film is disclosed. The film has a high average heat seal strength and physical strength. The VLDPE has a density within the range of about 0.880 to 0.914 g/cm3. The film has a seal initiation temperature lower than or equal to 95° C. and an average heat seal strength greater than or equal to 1.75 lb/in. The film has a machine-direction (MD) modulus greater than or equal to 12,000 psi. The film can be used as a monolayer film or as a layer of a multilayer film. It is suitable for heat sealable bags and many other applications.
摘要翻译:公开了一种非常低密度的聚乙烯(VLDPE)膜。 该膜具有高的平均热封强度和体力。 VLDPE的密度在约0.880-0.914g / cm 3的范围内。 该膜具有低于或等于95℃的密封起始温度和大于或等于1.75磅/英寸的平均热密封强度。 该膜具有大于或等于12,000psi的机器方向(MD)模量。 该膜可以用作单层膜或多层膜的层。 适用于热封袋和许多其他应用。
摘要:
Propylene polymer composites containing modified clays and compatibilizing agents, more specifically hydrogenated tallow modified montmorillonite and maleic anhydride grafted propylene polymers, are provided. Concentrates or masterbatches used to prepare the composites are also described. The improved composites of the invention exhibit increased melt strength compared to the base resin and to composites similarly formulated using other types of modified clays. Moreover, the improved results are achievable at lower compatibilizer levels and lower ratios of compatibilizer to clay than has heretofore been considered practical.
摘要:
A film comprising a polymer blend of: (a) 0.15 to 0.8 wt % of an LDPE having an MI of 0.1 to 0.6 dg/min; and (b) 99.2 to 99.85 wt % of an LLDPE produced with a single-site catalyst comprising a metallocene and having a haze (HZlldpe), dart impact (DIlldpe), MD-Tear (MDTlldpe), and a slice long chain branching index of at least 0.90 for any portion of the composition having a molecular weight of 100,000 or above, wherein the film has a haze (HZblend), a dart impact (DIblend), and an MD-Tear (MDTblend), and HZblend=a*HZlldpe, where a is 0.20 to 0.70; DIblend=b*DIlldpe, where b is 0.9 to 1.3; and MDTblend=c*MDTlldpe, where c is 0.8 to 1.1.
摘要翻译:一种膜,其包含:(a)0.15至0.8重量%的MI为0.1至0.6dg / min的LDPE的聚合物共混物; 和(b)99.2〜99.85重量%的由包含茂金属并具有雾度(HZlldpe),飞镖撞击(DIlldpe),MD-撕裂(MDTlldpe))和切片长链支化指数的单中心催化剂制备的LLDPE 对于具有100,000或更高分子量的组合物的任何部分,至少为0.90,其中该膜具有雾度(HZblend),飞镖冲击(DIblend)和MD-撕裂(MDTblend),HZblend = a * HZlldpe,其中a为0.20至0.70; DIblend = b * DIlldpe,其中b为0.9至1.3; 和MDTblend = c * MDTlldpe,其中c为0.8至1.1。