摘要:
An aqueous dispersion is claimed which is capable of forming a free-standing, coherent, elastomeric, solid film which, after drying and annealing at 80.degree. C. for 30 minutes, demonstrates a tensile strength of about 11.0 MPa or greater wherein the dispersion comprises: I. an organic phase comprising: (a) one or more block copolymer(s) corresponding to the formula A-B-X.sub.m -(B-A).sub.n, wherein each A polymer block consists essentially of a monovinylidene aromatic monomer, having a weight average molecular weight from about 8,000 to about 15,000 Daltons, each B polymer block consists essentially of a conjugated diene and, optionally, a monovinylidene aromatic monomer having a weight average molecular weight from about 30,000 to about 200,000 Daltons, X is the remnant of a multifunctional coupling agent, m is 0 or 1, and n is an integer from 1 to 5, and (b) optionally, an extender for the block copolymer which is compatible with the B block; II. a surfactant; and III. water, wherein the A block effective phase volume in the organic phase is from about 5 to about 20 percent.
摘要:
What is claimed is a coherent, elastomeric, solid, free-standing film comprising an organic phase comprising: (a) one or more block copolymer(s) corresponding to the formula:A--B--X.sub.m --(B--A).sub.nwherein each A is a polymer block consisting essentially of a monovinylidene aromatic monomer, each B is a polymer block consisting essentially of a conjugated diene and, optionally, a monovinylidene aromatic monomer, X is the remnant of a multifunctional coupling agent, m is 0 or 1, and n is an integer from 1 to 5, each monovinylidene aromatic monomer block having a weight average molecular weight from about 8,000 to about 15,000 Daltons, each conjugated diene block having a weight average molecular weight from about 30,000 to about 200,000 Daltons, and (b) optionally, an extender which is compatible with the B block; wherein the A block comprises 5 to 25 percent by weight of the organic phase and exhibits an effective phase volume in the organic phase from about 5 to about 20 percent and the amount of extender present is sufficient to achieve the desired effective phase volume of the A block, wherein the film is annealed and demonstrates a tensile strength of 11.0 MPa or greater.
摘要:
Disclosed are bituminous blends having improved toughness and elasticity. The blends contain a bituminous binder and a tapered block copolymer formed from a monovinyl aromatic compound and a conjugated diene. Suitable tapered block copolymers include a tapered A-B-A type block copolymer of the A-t-B-t-A configuration, particularly those having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent, and tapered A-B-A type block copolymers of the A-B-t-A configuration having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent of the total monovinyl aromatic compound in the tapered block copolymer. Further disclosed is a method of making the blends. Further disclosed is a tapered A-B-A type block copolymer having an isolated monovinyl aromatic compound content of about 29 to about 75 weight percent.
摘要:
An artificial latex comprising a stable aqueous colloidal dispersion of a preformed multiblock copolymer prepared using a sulfate of an ethoxylated phenol as a dispersing and stabilizing agent is described. This composition is particularly suitable for preparing articles such as gloves or condoms that are free of vulcanizing agents and proteins.
摘要:
Polymer blends having high impact resistance after mechanical working are produced by blending together a non-elastomeric monovinylidene aromatic polymer such as polystyrene with an elastomeric copolymer, such as a block copolymer of styrene and butadiene, in the form of crosslinked, colloidal size particles.
摘要:
An aqueous latex coating composition comprising a non-conductive, water-insoluble copolymer of (1) methacrylic acid or maleic acid, (2) a styrene compound, and (3) a conjugated diene hydrocarbon or an alkyl ester of methacrylic acid or of acrylic acid is coated onto a sheet which is conductive or is non-conductive but may have a conductive layer adhered thereto. Thereby, sheets having a dielectric coating for electrographic printing are produced.
摘要:
Polymer blends having high impact resistance after mechanical working are produced by blending together a non-elastomeric monovinylidene aromatic polymer such as polystyrene with an elastomeric copolymer, such as a block copolymer of styrene and butadiene, in the form of crosslinked, colloidal size particles.
摘要:
Preforms for molding processes are prepared by applying an aqueous dispersion of a tackifier onto one or more reinforcement fibers, (2) drying the coated reinforcement fibers to remove the water present and (3) forming one or more of the coated reinforcement fibers into a predetermined shape. The preforms comprise reinforcement fibers having a substantially uniformly distributed tackifier on the surface thereof in the form of a discontinuous film coating.
摘要:
The present invention is a method of preparing a high internal phase ratio emulsion without phase inversion comprising the steps of:a) continuously merging into a disperser and in the presence of an emulsifying and a stabilizing amount of a surfactant, a continuous phase liquid stream having a flow rate R.sub.1, and a disperse phase liquid stream having a flow rate R.sub.2 ; andb) mixing the merged streams with a sufficient amount of shear, and with R.sub.2 :R.sub.1 sufficiently constant, to form the high internal phase ratio emulsion without phase inversion or stepwise distribution of an internal phase into an external phase;wherein R.sub.2 :R.sub.1 encompasses a range, the lower limit of which range being defined by a point where the volume average particle size of the high internal phase ratio emulsion begins to show an inverse dependence on R.sub.2 :R.sub.1, and wherein the upper limit of which range is just less than an R.sub.2 :R.sub.1 where a phase inversion of the high internal phase ratio emulsion takes place.Monodisperse submicron particles can be prepared using the process of the present invention. Useful latexes can be prepared from these high internal phase ratio emulsions.
摘要:
Preforms for molding processes are prepared by applying an aqueous dispersion of a tackifier onto one or more reinforcement fibers, (2) drying the coated reinforcement fibers to remove the water present and (3) forming one or more of the coated reinforcement fibers into a predetermined shape. The preforms comprise reinforcement fibers having a substantially uniformly distributed tackifier on the surface thereof in the form of a discontinuous film coating.