Abstract:
The invention relates to a method for the production of porous materials by the expansion of polymer gels, to the porous materials produced by a method of this type and to a shaped body.
Abstract:
Vehicle tyre, notably a winter tyre, the tread of which comprises a rubber composition that is heat-expandable in the unvulcanized state and expanded in the vulcanized state; in the unvulcanized state, said composition comprises a diene elastomer such as natural rubber and/or a polybutadiene, more than 50 phr of a reinforcing filler such as silica and/or carbon black, between 5 and 25 phr of a sodium or potassium (hydrogen) carbonate, between 2 and 20 phr of an acid quaternary ammonium salt, the total content of (hydrogen) carbonate and acid salt being greater than 10 phr, preferably greater than 15 phr. The combined use of the last two compounds, at the recommended high contents, makes it possible to greatly improve the grip of the tyre on melting ice.
Abstract:
The invention relates to a process for preparing a cellulosic sponge comprising treating an aqueous suspension of cellulose fibers with periodate; adjusting the pH of the resulting dialdehyde cellulose fibers suspension to 2.5 to 5.5; freezing the suspension obtained and thawing the three dimensional structure to render the cellulosic sponge. The process may further comprise a step of drying to render a cellulosic foam. Both the new sponge and the new foam of the invention may also be further chemically modified obtaining a broad variety of derivatives with tailored properties which useful in many different applications.
Abstract:
Method for producing expanded thermoplastic elastomer particles, wherein thermoplastic elastomer particles are surrounded by a gaseous medium, said method comprising: a) an impregnation step, wherein the gaseous medium is at an impregnation temperature (T a ), the absolute pressure of the gaseous medium is greater than ambient pressure, and wherein a blowing agent is dissolved in the thermoplastic elastomer particles, b) an expansion step, wherein the thermoplastic elastomer particles are exposed to a pressure reduction at a first expansion temperature (T b ) and expand, and c) optionally, a welding step, wherein the expanded thermoplastic elastomer particles are welded to one another at a welding temperature (T c ) to form at least one shaped part, and wherein the thermoplastic elastomer particles are composed of amorphous thermoplastic elastomer or partially crystalline thermoplastic elastomer or mixtures thereof, the impregnation temperature (T a ), the first expansion temperature (T b ) and the welding temperature (T c ) depend on the type of thermoplastic elastomer, and i) if the thermoplastic elastomer is amorphous, are higher than a first limit temperature (T G-40 ), wherein the first limit temperature (T G-40 ) is 40 °C below the glass transition temperature (T G ) according to DIN EN ISO 11357-2:2013-09 of the non-impregnated thermoplastic elastomer particles, ii) if the thermoplastic elastomer is partially crystalline, are higher than the glass transition temperature (T G ) according to DIN EN ISO 11357-2:2013-09 of the non-impregnated thermoplastic elastomer particles and are lower than a second limit temperature (T S-5 ) which is 5 °C below the melting temperature (T S ) according to DIN EN ISO 11357-3:2013-04 of the non-impregnated thermoplastic elastomer particles.
Abstract translation:一种生产膨胀热塑性弹性体颗粒的方法,其中热塑性弹性体颗粒被气体介质包围,所述方法包括:a)浸渍步骤,其中气体介质处于浸渍温度(Ta),气体介质的绝对压力为 大于环境压力,并且其中发泡剂溶解在热塑性弹性体颗粒中,b)膨胀步骤,其中热塑性弹性体颗粒在第一膨胀温度(Tb)下暴露于减压并膨胀,以及c)任选地 ,焊接步骤,其中所述发泡热塑性弹性体颗粒在焊接温度(Tc)彼此焊接以形成至少一个成形部件,并且其中所述热塑性弹性体颗粒由无定形热塑性弹性体或部分结晶的热塑性弹性体或混合物 浸渍温度(Ta),第一膨胀温度(Tb)和 焊接温度(Tc)取决于热塑性弹性体的种类,i)如果热塑性弹性体是无定形的,高于第一极限温度(TG-40),其中第一极限温度(TG-40)为40° C低于非浸渍热塑性弹性体颗粒的DIN EN ISO 11357-2:2013-09的玻璃化转变温度(TG),ii)如果热塑性弹性体是部分结晶的,则高于玻璃化转变温度(TG) 根据DIN EN ISO 11357-2:2013-09的非浸渍热塑性弹性体颗粒,并且低于根据DIN EN ISO的熔点温度(TS)低5℃的第二极限温度(TS-5) 11357-3:2013-04的非浸渍热塑性弹性体颗粒。
Abstract:
Provided is a shoe sole member including a crosslinked foam forming a part or the whole of the shoe sole member, wherein the crosslinked foam is formed by a polymer composition showing specific results in measurement using pulsed NMR.
Abstract:
The invention relates to a compound for the production of high softness and thermal stability crosslinked articles made by injection molding, a process for the production thereof and an article produced with this compound. The compound comprises (a) a crosslinkable polyolefin, such as ethylene vinyl acetates (EVAs); (b) a thermoplastic polyurethane (TPU), polyether or polyester or mixtures thereof containing a plasticizer or not, wherein said TPU containing a plasticizer or not has a softening point determined via DSC lower than 160 °C, preferably lower than 130 °C; (c) a stabilizing polymer preferably selected from LDPE, HDPE, LLDPE, metallocene polyolefins with a melting point lower than 130 °C or mixtures thereof, in particular LDPE; (d) at least one crosslinking agent, in particular a peroxide or the like; (e) at least one foaming agent; and (f) optionally, one or more further additives selected from coagents, foaming agents, lubricants, kickers, fillers, pigments and oils, wherein (i) the weight ratio between crosslinkable polyolefin and TPU without the weight of any plasticizer present corresponds to a range from 100:100 to 100:3, preferably from 100:40 to 100:5, more preferably from 100:40 to 100:10, even more preferably from 100:30 to 100:15; (ii) the hardness of the TPU with or without plasticizer is in the range from 38 to 85 Shore A, preferably lower than 70 Shore A, even more preferably lower than 55 Shore A.
Abstract:
Provided are: a polyetherimide porous body which has a low relative permittivity and is not easily cracked (or is excellent in cracking resistance) when folded, and a method for producing the porous body. This polyetherimide porous body comprises a polyetherimide crosslinked body and has a gel fraction of 10 % or more, an average cell diameter of 8 µm or less, a volume porosity of 30 % or more and an insulation breakdown voltage of 30 kV/mm or more.