This disclosure describes compositions, kits, methods, systems, and three-dimensional parts. According to an example, described herein is a three-dimensional printed part made from three-dimensional printing, the three-dimensional part comprising: a thermoplastic polymer powder composition comprising a mixture of two or more polyolefins including at least 60 wt % of a C3 polyolefin based on the total weight of the mixture of the two or more polyolefins, wherein the thermoplastic polymer powder composition has a processing window of from about 120° C. to about 150° C.

An inflatable cellular cushioning article has a plurality of inflatable chambers with each chamber comprising a plurality of inflatable cells connected in series with one another by connecting channels. The article is made from a first multilayer film sealed to itself or to a second film. The first film comprises a plurality of microlayers. At least 50 percent of the microlayers comprise a polymer selected from the group consisting of ethylene homopolymer, ethylene copolymer, propylene homopolymer, and propylene copolymer.

An inflatable cellular cushioning article has a plurality of inflatable chambers with each chamber comprising a plurality of inflatable cells connected in series with one another by connecting channels. The article is made from a first multilayer film sealed to itself or to a second film. The first film comprises a plurality of microlayers. At least 50 percent of the microlayers comprise a polymer selected from the group consisting of ethylene homopolymer, ethylene copolymer, propylene homopolymer, and propylene copolymer.

Provided is a resin powder containing a polyolefin-based resin, wherein the average circularity of the resin powder is 0.950 or greater, a logarithmically converted value Log R of the volume resistivity R of the resin powder is 11.5 or less, and the degree of compression of the resin powder is 1.45 or less. An embodiment where the volume average particle diameter of the resin powder is 10 micrometers or greater but 150 micrometers or less, an embodiment where the resin powder further contains an antistatic agent, an embodiment where the antistatic agent is water-insoluble, and an embodiment where the content of the antistatic agent is 0.5% by mass or greater but less than 20% by mass relative to the total amount of the resin powder are preferable.

An apparatus is configured to make containers from sheet material. The apparatus includes a supply station for supplying a film having at least one folded portion having three or more film flaps folded and superimposed with respect to each other; a welding station configured to receive the film. The welding station comprises a welding head configured for welding the folded portion of the film and forming a container defining a housing compartment; the welding head comprises a heater made of electrically conductive material whose electrical resistivity, at least in a predetermined temperature range, decreases upon the increase of the temperature of the same electrically conductive material.

An apparatus is configured to make containers from sheet material. The apparatus includes a supply station for supplying a film having at least one folded portion having three or more film flaps folded and superimposed with respect to each other; a welding station configured to receive the film. The welding station comprises a welding head configured for welding the folded portion of the film and forming a container defining a housing compartment; the welding head comprises a heater made of electrically conductive material whose electrical resistivity, at least in a predetermined temperature range, decreases upon the increase of the temperature of the same electrically conductive material.

A method for thermoforming an article includes extruding a sheet of material, conditioning the sheet with a roller, thermoforming the sheet to provide a web, and cutting the web to provide the article.

This disclosure describes compositions, kits, methods, systems, and three-dimensional parts. According to an example, described herein is a threedimensional printing composition comprising: a polymeric powder build material comprising a thermoplastic polymer powder composition, wherein the thermoplastic polymer powder composition comprises: (a) at least 50 wt % of a C3 polyolefin, or a mixture of two or more polyolefins including at least 60 wt % of a C3 polyolefin based on the total weight of the mixture of the two or more polyolefins, (b) 0.1 to 1 wt % antioxidants, (c) 0.1 to 5 wt % flow aids, (d) 0-10 wt % of a surface modifying agent, (e) 0.05-wt %-10 wt % antistatic agents, (f) 2 wt % to 40 wt % filler, wherein the total of (a) to (f) is 100 wt %.

A biaxially oriented multilayer film may include at least one sealing layer including at least a linear low density polyethylene (LLDPE); and at least one core layer including at least a polypropylene copolymer. A biaxially oriented polypropylene multilayer film, may include at least one sealing layer comprising at least a polyethylene blend and at least one core layer comprising at least a polypropylene copolymer, wherein the polyethylene blend comprises at least a linear low density polyethylene (LLDPE) and at least a high density polyethylene (HDPE).

A polymer composition adapted for use in injection stretch blow molding may include a metallocene random propylene-based copolymer in the absence of a clarifier. The metallocene random propylene-based copolymer may exhibit a melting point of from 105° C. to less than 175° C., a recrystallization temperature ranging from 85° C. to 100° C. as measured by DSC, a microtacticity ranging from 89% to 99%, a molecular weight (Mw) ranging from 170,000 to 210,000, and a melt flow rate of from about 1 dg/min. to about 40 dg/min. A method of forming an injection stretch blow molded (ISBM) article may include providing the metallocene random propylene-based copolymer, injection molding the metallocene random propylene-based copolymer in the absence of a clarifier into a preform, and stretch-blowing the preform into an article.