摘要:
Prefoamed particles of a polyolefin resin are produced by dispersing starting particles of the polyolefin resin, which contains a volatile foaming agent, in a dispersant in a pressure vessel, heating the resultant dispersion to a temperature of at least the softening point of the starting particles in said pressure vessel and then opening the vessel at one end thereof so as to release the starting particles and dispersant into an atmosphere of a pressure lower than the internal pressure of the vessel. The release of the starting particles and dispersant is performed while feeding a heating liquid.
摘要:
Method of producing a molded article of a foamed thermoplastic resin. A molten mass of an expandable thermoplastic resin is accumulated in an accumulator while it is prevented from foaming. A predetermined quantity of the accumulated thermoplastic resin is ejected rapidly from the accumulator into the atmosphere so that the thermoplastic resin commences foaming. The ejected thermoplastic resin is placed in a mold cavity before the foaming expansion has been completed and is compressed. The expansion and molding of the ejected thermoplastic resin is completed in the mold while controlling the compression pressure to obtain a foamed molded article.
摘要:
There is provided a logic device wherein an alternating input signal having a frequency which is one of two frequencies allotted to two input logical values, respectively, positive logic "1" and negative logic "0", is inputted to the device. An output logical value is decided depending on the determination which frequencies the input frequency coincides with or not, and an alternating output signal having a frequency which corresponds to the output logical value is delivered out of the device. The logic device, even when constituted with semiconductor elements, can have highly reliable fail-safe capability and can be reduced in size and weight.
摘要:
This invention provides an electrical conductive foam bead comprising a foamed bead core of a thermoplastic synthetic resin at least partially covered on the surface thereof with an electrical conductive layer, and a molded electrical conductive foamed article comprising a plurality of particulate bodies formed by mutually fusing such electrical conductive foam beads, the electrical conductive layers extending over all or a portion of the interface of the mutually fused particulate bodies. The conductive foam beads and molded conductive foamed articles both have improved antistatic effect and are used as packaging and cushioning materials, electromagnetic radiation shields, and the like.
摘要:
A multi-hop wireless communication system which synchronizes a time signal generated by a timer device included in each of the wireless terminals and sets a different active timing to a wireless terminal connected to each of a plurality of multi-hop routes. The wireless terminal monitors the time signal of the timer device included in the wireless terminal and activates wireless communication of the wireless terminal when it is detected that the time signal matches an active timing set in the wireless terminal.
摘要:
Pre-foamed particles are produced by dispersing resin particles, which contain nucleocells, in a dispersing medium in a closed vessel, heating the contents to a temperature of the softening point of the particles or higher and holding the contents at the temperature for a predetermined period of time while pressurizing the contents with an inorganic gas, and then opening the vessel at one end thereof so as to release the particles and medium into an atmosphere of a pressure lower than the internal pressure of the vessel, thereby causing the resin particles to foam. The above production process provides good pre-foamed particles with ease and without failure. It is also possible to avoid deleterious effects due to the swelling action of foaming agents.
摘要:
Propylene-base random copolymer particles suitable for use in the production of pre-foamed particles are obtained by heating starting copolymer particles of ethylene-propylene random copolymer to the crystallization temperature thereof and then quenching them in a medium at a temperature of (the crystallization temperature-30.degree. C.) or lower. Pre-foamed particles produced using the copolymer particles contain large cells are columnar in shape with an average diameter D of 1.7 mm or less and an L/D.gtoreq.1. They can thus provide foamed moldings which are substantially free of shrinkage and have good flexibility.
摘要:
Disclosed herein are propylene-base random copolymer particles suitable for use in the production of pre-foamed particles. The copolymer particles are obtained by heating starting copolymer particles to the crystallization temperature thereof and then quenching them in a medium of (the crystallization temperature-30.degree. C.) or lower. Processes for obtaining the copolymer particles are also disclosed. Pre-foamed particles produced using the copolymer particles contain large cells. They can thus provide foamed moldings which are substantially free of shrinkage and have good flexibility.
摘要:
A process for producing a foamed and molded article of a polypropylene resin, which comprises pressurizing preliminarily-foamed particles of an ethylene/propylene copolymer having a melt index value of from 0.1 to 25, a latent heat of crystallization of not more than 28 cal/g and an ethylene content of from 1 to 30% by weight as a base resin with an inorganic gas or a gaseous mixture of the inorganic gas and a volatile blowing agent thereby to impart an elevated pressure to the inside of said particles, thereafter filling said particles in a mold capable of enclosing the particles but allowing escape of gases therefrom, and then heating said particles to expand them to the configuration of the mold.
摘要:
A multi-hop wireless communication system which synchronizes a time signal generated by a timer device included in each of the wireless terminals and sets a different active timing to a wireless terminal connected to each of a plurality of multi-hop routes. The wireless terminal monitors the time signal of the timer device included in the wireless terminal and activates wireless communication of the wireless terminal when it is detected that the time signal matches an active timing set in the wireless terminal.