摘要:
A water-containing polyolefin resin composition containing a polyolefin resin and a hydrophilic polymer and having a water content of 1 to 50% by weight which is suitable for use in preparation of polyolefin resin pre-expanded particles, and pre-expanded particles of a polyolefin resin prepared by pre-expanding the water-containing polyolefin resin composition the particles having a an apparent expansion ratio of 5 to 60, a closed cell ratio of 80 to 100% and an average cell diameter of 50 to 500 &mgr;m. The pre-expanded particles can be prepared without using a volatile blowing agent by dispersing resin particles made of a polyolefin resin composition containing a polyolefin resin and a hydrophilic polymer into an aqueous dispersion medium in a closed vessel to form a dispersion, heating to a temperature not lower than the softening point of the polyolefin resin to produce water-containing resin particles having a water content of 1 to 50% by weight, and releasing the aqueous dispersion from the closed vessel into a lower pressure than the inner pressure of the closed vessel, thereby expanding the water-containing resin particles. When the releasing of the dispersion from the vessel is conducted after raising the inner pressure to 25 to 75 kg/cm2G by introducing nitrogen gas, air or an inorganic gas including them as a main component into the vessel, pre-expanded particles providing foams having good physical properties and a high expansion ratio are obtained.
摘要:
There is provided pre-expanded particles of a propylene resin having a high expansion ratio and excellent molding adhesion without using a volatile blowing agent or increasing an expansion pressure. The pre-expanded particles of a propylene resin are prepared by the process comprising dispersing resin particles comprising a propylene resin composition, which contains 100 parts by weight of (A) a random copolymer of ethylene and propylene having an ethylene content of 1.5 to 4.5% by weight and 0.001 to 10 parts by weight of (B) an alkali metal salt of a copolymer of ethylene and (meth)acrylic acid, into an aqueous dispersion medium in a pressure vessel to obtain a mixture, heating the mixture to an expansion temperature higher than a softening temperature of the resin particles, introducing an inorganic gas, and releasing the mixture into a lower atmosphere than the inner pressure of the pressure vessel; said mixture is expanded after a temperature of said mixture is maintained at a temperature region of not more than the expansion temperature to at least (the expansion temperature -1.degree. C.) for at least 30 minutes.
摘要:
There is provided pre-expanded particles of a propylene resin having a high expansion ratio and excellent molding adhesion without using a volatile blowing agent or increasing an expansion pressure. The pre-expanded particles of a propylene resin are prepared by the process comprising dispersing resin particles comprising a propylene resin composition, which contains 100 parts by weight of (A) a random copolymer of ethylene and propylene having an ethylene content of 1.5 to 4.5% by weight and 0.001 to 10 parts by weight of (B) an alkali metal salt of a copolymer of ethylene and (meth)acrylic acid, into an aqueous dispersion medium in a pressure vessel to obtain a mixture, heating the mixture to an expansion temperature higher than a softening temperature of the resin particles, introducing an inorganic gas, and releasing the mixture into a lower atmosphere than the inner pressure of the pressure vessel; said mixture is expanded after a temperature of said mixture is maintained at a temperature region of not more than the expansion temperature to at least (the expansion temperature −1° C.) for at least 30 minutes.
摘要:
A process for preparing pre-expanded particles of a thermoplastic resin without washing the prepared pre-expanded particles to remove a dispersing agent remaining thereon and without discharging waste water, which comprises charging particles of a thermoplastic resin and an aqueous dispersion medium containing a dispersing agent into a closed pressure vessel, heating the resulting aqueous dispersion to a temperature of not less than the softening point of the thermoplastic resin, thereby impregnating the particles with water to have a water content of 1 to 50% by weight, releasing the dispersion into a lower pressure atmosphere, thereby expanding the particles, recovering the dispersion medium containing the dispersing agent, and recycling it as a dispersion medium to the pressure vessel.
摘要:
Post-treatment method of polyolefin resin pre-expanded particles comprising: introducing the polyolefin resin pre-expanded particles foamed by using an inflammable blowing agent into an extraction vessel filled with steam previously; feeding an additional steam into the extraction vessel; extracting the inflammable blowing agent gas from the polyolefin resin pre-expanded particles; discharging the resulting steam which contains the extracted inflammable blowing agent gas from the extraction vessel continuously or intermittently; and liquefying the steam to separate and recover the inflammable blowing agent gas. According to the post-treatment method of polyolefin resin pre-expanded particles, the inflammable blowing agent can be extracted from the pre-expanded particles in a short period of time and the extracted inflammable blowing agent can be re-used.
摘要:
To provide a process for preparing polyolefin resin pre-expanded particles which enables to prepare pre-expanded particles having lower fluctuation in expansion ratios. Polyolefin resin pre-expanded particles are prepared by a process comprising steps of dispersing polyolefin resin particles into an aqueous dispersion medium in an autoclave; heating the resin particles to temperature of at least the softening point of the polyolefin resin and pressuring the same; releasing said resin particles from the autoclave through a release port into an atmosphere of lower pressure than the inner pressure of the autoclave; thereby pre-expanding the resin particles, wherein at the releasing step, the resulting pre-expanded particles are contacted with gas of at least 60° C. and collided with a collision board or a container wall disposed at a distance of 5 mm
摘要:
The present invention provides a method of recovering volatile foaming agent contained in prefoamed beads of polyolefin resin characterized in that the volatile foaming agent contained in the prefoamed beads is recovered by bringing into contact with heated air prefoamed beads obtained by heating polyolefin resin beads containing the volatile foaming agent. According to the invented method it is possible to avoid not only aggravation of the working environments and atmospheric pollution but also risk of explosion etc. and, furthermore, material cost can be saved through reutilization of the recovered volatile foaming agent.
摘要:
An object of the present invention is to provide an inmold foaming method of a polyolefin based resin foamed article, wherein a pre-foamed particle having a large bulk density, which could be molded only by an impregnation method based on conventional technology having defect of expensive plant-and-equipment investment expense, may be molded using a compression filling molding method advantageous in productivity and plant-and-equipment investment expense, and thereby a charging ratio and surface appearance of the foamed article to be obtained may also be improved. The present invention is an inmold foaming method of a polyolefin based resin foam for charging, into a molding space, a pre-foamed particle including a polyolefin based resin as a base material resin, and having a bulk density of 30 kg/m3 to 100 kg/m3, and a DSC ratio of 5% to 35%, while pressurizing with an inorganic gas, and for heating with steam and welding the pre-foamed particle, wherein a pressurizing treatment of the pre-foamed particle is performed with a pressure of 0.3 MPa to 1.0 MPa with an inorganic gas before charging.
摘要翻译:本发明的目的在于提供一种聚烯烃系树脂发泡体的发泡成型方法,其特征在于,具有大体积密度的预发泡粒子,其可以仅通过基于传统技术的浸渍方法成型,所述技术具有昂贵的缺陷 可以使用有利于生产率和设备投资费用的压缩填充成型方法来模制设备投资费用,从而也可以提高要获得的发泡制品的装料率和表面外观。 本发明是一种聚烯烃系树脂发泡体的成型发泡方法,其特征在于,在成形空间中,将包含聚烯烃系树脂作为基材树脂的预发泡粒子进行充填,所述预发泡粒子的体积密度为30kg / m 2 > 3℃至100kg / m 3,DSC比率为5%至35%,同时用无机气体加压,并用蒸汽加热并将预发泡颗粒 其中,在充电前用无机气体以0.3MPa〜1.0MPa的压力进行预发泡粒子的加压处理。
摘要:
A process for post-treating pre-expanded polyolefin resin particles which comprises charging in a vessel pre-expanded polyolefin resin particles which are pre-expanded by using an inflammable blowing agent, supplying an inert gas into the vessel, and then discharging the inert gas with the inflammable blowing agent gas extracted from the pre-expanded polyolefin resin particles, from the vessel. According to the process of the invention, the inflammable blowing agent can be extracted efficiently, safely and in a short time from the pre-expanded polyolefin resin particles which are pre-expanded by using the inflammable blowing agent. Consequently, the spontaneous cambustion of the particles can be completely avoided even if sparks are generated on the surface of the pre-expanded particles, therefore, it becomes easy to handle the pre-expanded polyolefin resin particles because the particles can be dried and transported by a pneumatic conveyer.
摘要:
Pre-expanded particles of polyolefin resin having less fluctuation in expansion ratio, uniform particle size and low expansion ratio are provided without using any volatile foaming agent. The low expansion ratio means 2 to 10 times, preferably 3 to 8 times. Resin particles to be released are uniformly contacted with saturated vapor at the time of pre-expanding polyolefin resin particles by dispersing the resin particles into an aqueous dispersion medium in a closed vessel, heating the resin particles to temperature of at least the softening point of the polyolefin resin and releasing the particles from the closed vessel into an atmosphere of lower pressure than the inner pressure of the closed vessel.