摘要:
A pre-expanded particle suitable for foaming in a mold comprising non-crosslinked linear low density polyethylene which has a characteristic property that an inclination of slope line obtained on a graph when logarithmic values of melt tension of the polyolefin are plotted as ordinate and reciprocals of absolute temperature at which the melt tension is measured are plotted as abscissa is not more than 1,500 is provided. A foamed article produced from the pre-expanded particles has an excellent appearance, a flat surface and good mechanical strength, and is useful for wrapping material, insulating material, a container or a fender of cars.
摘要:
A pre-expanded particle suitable for foaming in a mold comprising polyolefin which has a characteristic property that an inclination of slope line obtained on a graph when logarithmic values of melt tension of the polyolefin are plotted as ordinate and reciprocals of absolute temperature at which the melt tension is measured are plotted as abscissa is less than 1,500 is provided. A foamed article produced from the pre-expanded particles has an excellent appearance, a flat surface and good mechanical strength, and is useful for wrapping material, insulating material, a container or a fender of cars.A process for preparing the above-mentioned pre-expanded particles is also disclosed.
摘要:
The mixture of water and the polyolefin resin particles impregnated with a volatile blowing agent are released from the interior of the pressure-resistant container under a constant temperature and constant pressure preferably keeping the partial pressure of the blowing agent constant, through at least one orifice having an area of 0.07 to 300 mm.sup.2, into a low-pressure zone.This invention gives various advantages when applied to the practical process resulting in expanded particles with superior properties which are free of blocking and remarkably uniform in the degree of expansion, and are useful for molding.
摘要:
Expandable thermoplastic polymer beads and method of producing same, wherein a core of a polymer of one or more vinyl monomers is substantially surrounded by a layer of a polyolefin comprising one or more vinyl monomers, with a foaming agent contained in at least the core.
摘要:
Expandable thermoplastic polymer beads and method of producing same, wherein a core of a polymer of one or more vinyl monomers is substantially surrounded by a layer of a polyolefin comprising one or more vinyl monomers, with a foaming agent contained in at least the core.
摘要:
A pre-expanded particle made of a blend of 10 to 90% by weight of a polypropylene resin having a melt index of 6 to 10 g/10 minutes and 90 to 10% by weight of a polypropylene resin having a melt index of 0.5 to 3 g/10 minutes. The melt index of the blend being within the range of 2 to 5 g/10 minutes. The pre-expanded particles can be molded by an in-mold foaming method in a short time without causing sink to give polypropylene resin cellular molded articles having good surface property and good melt adhesion of the particles.
摘要:
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing the dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40.degree. C. According to the process of the present invention, there can be obtained pre-expanded thermoplastic resin particles with a large average diameter of cells. By molding the pre-expanded particles obtained by the present invention, molded articles which are small in dimensional shrinkage and excellent in surface appearance can be obtained without imparting expandability to the particles or aging the particles under pressure prior to molding.
摘要:
A pre-expanded particle of a non-crosslinked linear low density polyethylene having an average cell diameter as large as 120 to 1,200 .mu.m which can be molded, without further imparting an expandability prior to molding or without aging under pressure, by heating in a closed mold permeable to a fluid heating medium such as steam to form a well bonded unitary cellular molded article having a good appearance, a high expansion ratio and improved heat resistance and mechanical property with a slight volumetric shrinkage.
摘要:
It is intended to provide resin foamed particles having a high environmental compatibility. Furthermore, it is intended to provide an economical and easy-to-use method of producing resin foamed particles having biodegradability without using a crosslinking agent, which should be handled with care, in the step of producing foamed resin particles. It is also intended to provide a molded article made of foamed particles having an extremely high heat insulating property and a biodegradability. Thermoplastic polyester-type resin foamed particles, in which the ratio of cells with diameter of 50 μm or less amounts to 20% or more in an arbitrary two-dimensional section of a thermoplastic polyester-type resin foamed particles, are first produced and then a molded article is produced with the use of these resin foamed particles.
摘要:
An extruded foam excelling in environmental friendliness and having biodegradability; and a stable process for producing the same. There is provided a process for producing an extruded foam of P3HA resin, characterized by melt-kneading a copolymer (poly(3-hydroxyalkanoate), P3HA) having at least one type of repeating unit of the formula: —O—CHR—CH2—CO— (1) (wherein R is an alkyl group represented by CnH2n+1 and n is an integer of 1 to 15) produced by a microorganism, a volatile foaming agent, a fatty acid amide compound and/or liquid paraffin to thereby obtain a mixture and extruding the mixture through molding die into a low-pressure zone.