摘要:
The present invention relates to bituminous compositions, particularly suitable for paving and building waterproofing, comprising a bitumen and a copolymer of ethylene with propylene and/or other alpha-olefins and optionally with smaller proportion of a diene or polyene. The copolymer is besides characterized by a very low crystallinity, intrinsic viscosity higher than 1.5 dl/g and by a content of propylene units or of the alpha-olefin in form of triads comprised between 4 and 50% of the propylene or of the alpha-olefin, with at least 70% of said triads having isotactic structure.
摘要:
Shaped articles for biomedical use characterized by a good transparency and flexibility also at low temperatures are prepared starting from elastomeric copolymers of ethylene with propylene and/or other alpha-olefins having a unique set of mechanical properties and thermoplastic processability. Of particular interest are devices for containing, administering, draining and transport of blood and biological and physiological fluids, syringe seals and similar applications.
摘要:
Composite sheets comprising a layer of cellulosic fibers and a layer adjacent thereto consisting in whole or in part of thermoplastic fibers are made to adhere by superimposing the sheets on the side of the cellulosic fibers layer and by inserting between such layers a film of a thermoplastic polymer having:(a) a melting temperature lower than the melting temperature of the polymer forming the thermoplastic synthetic fibres contained in the layer adjacent to the cellulosic layer, intended for the adhesion, of the composite sheet;(b) a viscosity in the molten state--measured in a capillary viscosimeter, at a velocity gradient equal to or lower than 10.sup.-1 seconds, and at a temperature comprised between a temperature higher by 10.degree. C. than the melting temperature of such polymer and a temperature higher by 20.degree. C. than the melting temperature of the abovesaid thermoplastic fibres--lower than 1.multidot.10.sup.8 poises, and preferably lower than 1.multidot.10.sup.5 poises;(c) a surface tension not exceeding by more than 5 dynes/cm the surface tension of the polymer forming such thermoplastic fibres, measured at the same temperature;(d) a solubility parameter, at a temperature of 25.degree. C., in a ratio of from 0.8 to 1.15, extremes included, to the solubility parameter of the polymer forming such thermoplastic fibres; andby heating the whole at a temperature ranging from a temperature exceeding by 10.degree. C. the melting temperature of the polymer forming such film to a temperature exceeding by 20.degree. C. the melting temperature of the polymer forming the synthetic fibres existing in the layer which is adjacent to the cellulosic fibre layer, intended for the adhesion, of the composite sheet.
摘要:
Polyolefin compositions comprising: (A) 20 to 50 parts by weight of a particular propylene polymer having a MWD greater than 3.5; and (B) 50 to 80 parts by weight of an elastomeric ethylene copolymer having a low enthalpy of fusion and a narrow MWD. The compositions of the invention are capable of giving, after dynamic vulcanization, thermoplastic elastomeric products having optimum elastomeric properties and a good balance of physico-mechanical properties.
摘要:
The present invention relates to polyolefin compositions comprising: (a) 20 to 50 parts by weight of a particular propylene polymer having an MWD greater than 3.5; and (b) 50 to 80 parts by weight of an elastomeric ethylene copoymerR having a low enthalpy of fusion and a narrow MWD. The compositions of the invention are capable of gining, after dynamic vulcanization, thermoplastic elastomeric products having optimum elastomeric properties and a good balance of physico-mechanical properties
摘要:
This invention relates to plastoelastomeric polyolefinic compositions comprising an intimate mixture of the following components, in the indicated percentages by weight:A) 10-50% of non cross-linked polypropylene;B) 2-10% of ethylene/propylene/(diene)non cross-linked elastomeric copolymer,C) 30-40% of polymeric product which is insoluble in xylene at 135.degree. C., comprising polypropylene and ethylene/propylene/(diene) copolymer, andD) 5-58% of an extender oil.This invention also relates to a process for preparing the above compositions, which consists in subjecting to vulcanization under dynamic conditions a mixture comprising, in % by weight:A) 20-80% of polypropylene,B) 80-20% of ethylene/propylene/(diene) elastomeric copolymer,C) 0.1-10%, referred to such copolymer, of a peroxide,D) 5-60%, referred to such peroxide, of a furan derivative as a cross-linking coadjuvant.and in adding, after vulcanization, the extender oil in an amount ranging from 6 to 100% calculated on the vulcanized product.
摘要:
This invention relates to plastoelastomeric polyolefinic compositions comprising an intimate mixture of the following components, in the indicated percentages by weight:(A) 10-50% of non cross-linked polypropylene;(B) 2-10% of ethylene/propylene/(diene) non cross-linked elastomeric copolymer,(C) 30-40% of polymeric product which is insoluble in xylene at 135.degree. C., comprising polypropylene and ethylene/propylene/(diene) copolymer, and(D) 5-58% of an extender oil.This invention also relates to a process for preparing the above compositions, which consists in subjecting to vulcanization under dynamic conditions a mixture comprising, in % by weight;(A) 20-80% of polypropylene;(B) 80-20% of ethylene/propylene/(diene) elastomeric copolymer,(C) 0.1-10%, referred to such copolymer, of a peroxide,(D) 5-60%, referred to such peroxide, of a furan derivative as a cross-linking coadjuvant.and in adding, after vulcanization, the extender oil in an amount ranging from 6 to 100% calculated on the vulcanized product.
摘要:
Polyolefinic fibers for use in the manufacture of synthetic paper are rendered readily water-dispersible by pre-treatment with a hydrophilic polymer which is a condensate of polyvinyl alcohol and aliphatic aldehydes containing from 1 to 6 carbon atoms, which condensates contain from 2 to 8 aldehyde residues per 100 units of polyvinyl alcohol.