摘要:
Compositions foamable by exposure to microwave energy contain: (A) at least one compound bearing crosslinkable organic radicals for crosslinking, (B) at least one blowing agent which releases gas on heating, (C) at least one metal powder or metal compound, for example a metal oxide, individually, or a mixture thereof, which has microwave activity. Foams of uniform cell structure can be formulated with wide processing latitude.
摘要:
A plastic is converted from an initial condition with a higher density into a foamed condition with a lower density using a blowing agent, wherein the plastic is cross-linked prior to foaming by means of a first cross-linking agent and during the foaming by means of at least one second cross-linking agent.
摘要:
The invention discloses methods for making foams by photopolymerizing emulsions comprising a reactive phase and a phase immiscible with the reactive phase components. Foams made from water-in-oil emulsions, including high internal phase emulsion are disclosed. Articles and uses for the foams are also described.
摘要:
A process for producing an automotive molded roof material is provided which comprises sheeting a foamable sheet forming composition comprising a specified propylene resin, a glass fiber, a radical initiator, a crosslinking auxiliary and a foaming agent in specific proportions into a foamable sheet, lining one side of the foamable sheet with a backing sheet so as to integrate these and irradiating the foamable sheet with ionizing radiation to thereby crosslink the propylene resin, followed by heating the foamable sheet so as to cause the foamable sheet to foam, placing a cover sheet on the other side of the foamed sheet before the sheet cools to solidify and press molding the cover sheet on the foamed sheet to cover. There is also provided an automotive molded roof material produced by the above process. An automotive molded roof material is obtained which can be recycled, is lightweight and has high rigidity.
摘要:
The foamable silicone rubber composition is capable of giving a cured silicone rubber body having a cellular structure and suitable for use as a very reliable fire-resistant joint-sealing member in buildings. In addition to the rather conventional constituents essential in a foamable silicone rubber composition of prior art including (a) a diorganopolysiloxane, (b) a finely divided reinforcing silica filer, (f) a curing agent and (g) a blowing agent, the foamed silicone rubber body obtained by curing the inventive composition is imparted with very reliable fire resistance by virtue of the synergistic effect of the characteristic ingredients including (c) a ferrite powder, (d) a finely divided inorganic material or, in particular, mica flakes, and (e) a platinum compound, in combination, each in a specified amount.
摘要:
A copolyimide foam comprising the reaction product of one or more of an aromatic tetracarboxylic acid and a compound of the formula: ##STR1## where x is an integer from 1 to 12 and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and are hydrogen or C.sub.1 to C.sub.6 linear or branched alkyl a mixture thereof with two or more diamines at least one of which being a heterocyclic diamine having a nitrogen atom in the ring and the other being a para- or meta-substituted aromatic diamine free of aliphatic substitution.Processes for producing the above copolyimide foam are also disclosed.
摘要:
Described are ways of improving the yields of specification grade polyimide foam on a consistent basis from one run to the next by use of improvements in microwave-based foaming processes. While a body of polyimide precursor is exposed to microwave radiation, the body of polyimide precursor and of the foam structure as it is developing therefrom are kept under a substantially vapor-impermeable microwave-compatible shroud that does not substantially restrict or impede development of the foam structure. For this purpose use may be made of a shroud composed of a polymer film. Mechanisms by which the shroud produces the improved results are discussed, and methods based thereon are set forth.
摘要:
Described are ways of improving the yields of specification grade polyimide foam on a consistent basis from one run to the next by use of improvements in microwave-based foaming processes. While a body of polyimide precursor is exposed to microwave radiation, the body of polyimide precursor and of the foam structure as it is developing therefrom are kept under a substantially vapor-impermeable microwave-compatible shroud that does not substantially restrict or impede development of the foam structure. For this purpose use may be made of a shroud composed of a polymer film. Mechanisms by which the shroud produces the improved results are discussed, and methods based thereon are set forth.
摘要:
The invention relates to the process of the invention provides a radiation-crosslinked polypropylene foam by extrusion at a low temperature (about 170.degree. C.) below the decomposition point of the blowing agent. The resulting foamed item has by far better heat resistance than conventional ones.The raw resin can be prepared by mixing a resin in the pellet form and a blowing agent in the powder form on account of the low-temperature flowability. Heretofore, such mixing was impossible because the blowing agent does not disperse completely.This outstanding effect of the invention was not expected at all from the known prior arts.
摘要:
A heat-foamable olefinic resin composition comprising(a) an ethylenic polymer,(b) a propylene/alpha-olefin copolymer having a melting point of 130.degree. to 160.degree. C.,(c) a propylene polymer having a melting point at least 10.degree. C. higher than the melting point of the propylene/alpha-olefin copolymer, and(d) a blowing agent, and optionally(e) a crosslinking agent and/or a crosslinking promoting agent; anda process for producing an olefinic resin foam comprising crosslinking and heat-foaming the aforesaid heat-foamable olefinic resin composition.