Mixture for manufacture of pencil leadsdoi:US2682476 ANURNBERG GEORG LOYUSUS2682476 * Nov 21, 1950 Jun 29, 1954 Staedtler J S Mixture for manufacture of pencil leads
In spite of the name, pencil leads do not contain the toxic chemical element lead, but are typically made with graphite and clay, or plastic polymers. 尽管名称叫做“铅”,铅笔铅不包含有毒的化学元素铅,而通常用的是石墨和粘土,或塑料聚合物。 LASER-wikipedia2 The first patent for a refillab...
• Color pencil leads, also used by artists and popular with children and students, are made through a similar process of creating a blend of pigment, china clay and wax that is extruded into a lead. Some basic sets of color pencils come with 12 or 24 colors per carton, but other hig...
The pencil leads prepared by the Conte process consist of a mixture of graphite and clay. The graphite, having been pulverized and subjected to any necessary purifying processes, is "floated" through a series of settling tanks, in each of which the comparatively heavy particles sink, and only ...
are graded on the Euro-pean system. This system of naming used B for black and H for hard; a pencil’s grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones. Then the standard writing pe...
Individual pencils cut from the sandwich are ready for further processing. Any pencils with defects, such as uncentered leads or chipped wood, are discarded at this point. Next, each pencil is painted in a machine receiving from 4-10 coats of lacquer, depending on the desired quality of the...
based on the different contents of clay and on the increased ceramization of the leads due to the sintering conditions used with leads of increasing hardness. Standardization would be possible, at least with the leads of the two manufacturers investigated here if the raw mixture were standardized...
are graded on the European system. This system of naming used B for black and H for hard; a pencil’s grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones. Then the standard writing penci...
I like writing with mechanical pencils, but one major frustration I have is with leads. It's difficult to find just the right type of lead to suit. I don't like leads that are too hard and etch into the paper, but I also don't like leads that are too sof
, the bath is first heated and the immersion may be at room temperature, desirably for about three hours. The leads are then removed from the bath, drained, dried in sawdust and spread on a screen overnight at room temperature to allow complete evaporation of the alcohol from the leads....