摘要:
This invention relates to a flame retardant composition comprising: (a) 81 to 99.99 weight percent of a thermoplastic resin, thermoset resin, thermoplastic resin blend, or thermoset resin blend which upon burning forms a char and (b) 0.01-19 weight percent of a silsesquioxane resin having a weight average molecular weight of greater than 300.
摘要:
A free-flowing silicone rubber powder, having an average particle size of 1 to 1000 microns and prepared by mixing a polydiorganosiloxane with a silica filler, is uniformly dispersed in a poly(phenylene ether) resin using conventional equipment, such as a single screw or, preferably, a twin screw extruder. When employed at relatively low concentrations, such as about 0.2 to 3 parts by weight of powder per 100 parts by weight of resin, a significant improvement in the processability is obtained, while modification at higher levels, such as 5 to 20 parts by weight of powder per 100 parts by weight of the resin results in a resin composition having greatly augmented impact resistance.
摘要:
There is disclosed a polyolefin composition which can be extruded at relatively high rates to provide extrudate having a low surface roughness (sharkskin), said composition comprising (A) 100 parts by weight of a polyolefin resin; and (B) 0.01 to 1 part by weight of a hydroxy-functional diorganopolysiloxane process aid, said diorganopolysiloxane having a number average molecular weight of at least 10,000. In particularly preferred embodiments, a hydroxy-functional diorganopolysiloxane in combination with a low density polyethylene is used as a process aid for linear low density polyethylene.
摘要:
The present invention, therefore, relates to a method for preparing a thermoplastic elastomer, said method comprising: (I) mixing (A) a thermoplastic resin comprising more than 50 percent by volume of a polyester resin other than poly(butylene terephthalate), said thermoplastic resin having a softening point of 23° C. to 300° C., (B) a silicone elastomer comprising (B′) 100 parts by weight of a diorganopolysiloxane gum having a plasticity of at least 30 and having an average of at least 2 alkenyl groups in its molecule and, optionally, (B″) up to 200 parts by weight of a reinforcing filler, the weight ratio of said silicone elastomer (B) to said thermoplastic resin (A) being greater than 35:65 to 85:15, (C) 0.01 to 5 parts by weight of a stabilizer for each 100 parts by weight of said thermoplastic resin and said silicone elastomer, (D) an organohydrido silicon compound which contains an average of at least 2 silicon-bonded hydrogen groups in its molecule and (E) a hydrosilation catalyst, components (D) and (E) being present in an amount sufficient to cure said diorganopolysiloxane (B′); and (II) dynamically curing said diorganopolysiloxane (B′).
摘要:
There is disclosed a method for preparing a thermoplastic elastomer, said method comprising:(I) mixing(A) a thermoplastic resin selected from the group consisting of a polyolefin and a poly(butylene terephthalate),(B) a diorganopolysiloxane having a plasticity of at least 30 and having an average of at least 2 alkenyl radicals in its molecule,(C) an organohydrido silicon compound which contains an average of at least 2 silicon-bonded hydrogen groups in its molecule,(D) optionally, a reinforcing filler and(E) a hydrozilation catalyst; and(II) dynamically curing said diorganopolysiloxane (B), wherein the amount of said diorganopolysiloxane (B) used is such that at least one property of the thermoplastic elastomer selected from tensile strength or elongation is at least 25% greater than the respective property for a corresponding simple blend wherein said diorganopolysiloxane is not cured.
摘要:
A method of dispersing silicone compositions in organic thermoplastic materials is disclosed. The novel compositions produced by the method of the invention have a fine and relatively uniform dispersion or organosilicone in an organic thermoplastic. An organosilicone resin (A) and a predominantly linear silicone fluid (B) are first blended to substantial homogeneity to form an organosilicone alloy therefrom. The organosilicone alloy exhibits thermoplastic behavior and has a temperature-dependent complex viscosity .eta.*.sub.Si (T) associated therewith. Likewise the organic thermoplastic materials have a temperature-dependent complex viscosity, .eta.*.sub.OTP (T), associated therewith. The organic thermoplastic and the organosilicone alloy are thereafter mixed at a predetermined mixing temperature, T.sub.m, and a predetermined shear strain rate. The organic thermoplastic material and the organosilicone alloy are both in a flowable state at T.sub.m. The value of T.sub.m is selected to be about .+-.30.degree. C. of a temperature, T.sub.0, wherein the absolute value of {72*.sub.OTP (T.sub.0)-.eta.*.sub.Si (T.sub.0)} is at its lowest value, at the predetermined shear strain rate.
摘要:
There is disclosed a polyolefin composition which can be extruded at relatively high rates to provide extrudate having improved hydrophobicity, said composition comprising (A) 100 parts by weight of a polythylene resin; and (B) 1 to 5 parts by weight of an interactive diorganopolysiloxane process aid, said diorganopolysiloxane having a number average molecular weight of at least 10,000. In particularly preferred embodiments, an interactive diorganopolysiloxane in combination with a low density polyethylene is used as a process aid for linear low density polyethylene.
摘要:
Thermoplastic elastomers are disclosed which are prepared by; (I) mixing, (A) a thermoplastic resin comprising more than 50 percent by volume of a polyamide or a polyester resin, (B) a silicone base comprising; (B′) 100 parts by weight of a diorganopolysiloxane gum having a plasticity of at least 30 and having an average of at least 2 alkenyl groups per molecule and (B″) 5 to 200 parts by weight of a reinforcing filler, wherein the weight ratio of said silicone base to said polyamide or polyester resin is from 35:65 to 85:15, (C) a compatibilizer, (D) a radical initiator, present in an amount sufficient to cure said diorganopolysiloxane gum, and optionally (E) a stabilizer, (II) dynamically vulcanizing said diorganopolysiloxanes gum, wherein at least one property of the thermoplastic elastomer selected from tensile strength or elongation is at least 25% greater than the respective property for a corresponding simple blend wherein said diorganopolysiloxane is not cured and said thermoplastic elastomer has an elongation of at least 25%.
摘要:
A thermoplastic elastomer composition, method of preparation, and article prepared therefrom. The thermoplastic elastomer composition comprising (A) a thermoplastic elastomer, (B) a thermoplastic resin which has Rockwell hardness (R scale) exceeding 80 at 25° C., (C) a polydiorganosiloxane which has a Williams plasticity exceeding 100 at 25° C.; and (D) an inorganic filler.
摘要:
A composition comprising a polyolefin, a polyorganosiloxane having at least two alkenyl groups per molecule, and calcium silicate where the polyorganosiloxane is cured after mixing using an organohydrido silicon compound and a hydrosilation catalyst to create a thermoplastic vulcanizate, provides excellent fire resistance. In particular such compositions when tested by burning at 40 to 88 kW/m2 external flux generate significantly less heat and smoke, and generate tougher chars compared to polyolefins alone, or mixtures of thermoplastic polyolefin resin, polyorganosiloxane and calcium silicate where the composition is not cured after mixing.