Abstract: A method for determining an amount of metallic impurities within silicon. The method includes the steps of (a) providing a rodlike silicon sample and a rodlike seed crystal in a zone melting apparatus, (b) zone melting to form a single silicon crystal having a conical end region with a droplike melt forming at the end of the single silicon crystal in a separation step, (c) cooling of the droplike melt to form a solidified silicon drop, (d) partial or complete dissolution of the silicon drop in an acid, and analyzing the solution obtained in step (d) by a trace analysis technique. Wherein the separation step further includes a remelting step for the silicon sample to reduce its diameter, forming a droplike melting zone, and separation of the seed crystal and the silicon sample by moving the seed crystal and the silicon sample apart from one another.

Abstract: A process for for producing or preparing chlorosilanes. The process includes providing chlorosilanes having the general formula HnSiCl4-n wherein n is from 1 to 3. Once provided, the chlorosilanes are placed into a fluidized bed reactor where a hydrogen and silicon tetrachloride-containing reaction gas is reacted with a particulate contact mass containing silicon at temperatures of 350° C. to 800° C. The operating granulation is understood as meaning the granulation or granulation mixture introduced into the fluidized bed reactor contains at least 1% by mass of silicon-containing particles S described by a structural parameter S. Where the S has a value of at least 0 and is calculated as follows S=(?s?0.70)·?SD/?F where ?S is a symmetry-weighted sphericity factor; the ?SD is a poured density [g/cm3], and the ?F is an average particle solids density [g/cm3].

Abstract: A process for preparing silane-terminated polymers (SP) of the formula (I), Y—[O—C(?O)—NH—(CR12)b—SiRa(OR2)3-a]x??(I), includes in a 1st process step at least one polymer (OHP) of the formula (II), Y—[OH]x??(II), being reacted with at least one isocyanate-functional silane (IS) of the formula (III), O?C?N—(CR12)b—SiRa(OR2)3-a??(III), with the proviso that the isocyanate-functional silanes (IS) are used in an amount such that there are at least 1.05 isocyanate groups in the silanes (IS) to each hydroxyl group in the compounds (OHP). Subsequently, in a 2nd process step, the unreacted isocyanate groups of the silanes (IS) are reacted, in the reaction mixture obtained in the 1st process step, with at least one alcohol (A) of the formula (IV), R3OH??(IV) Subsequently, in a 3rd process step, the reaction mixture obtained in the 2nd process step is passed through an evaporation unit (VD).

Abstract: Silphenylene polymers along with processes for producing and uses for the same. Where the Silphenylene polymers have the formula (I) RaR1bSi[Y[(SiR2cR3d)e]f]gYSiRaR1b ??(I). At least one olefinically or acetylenically unsaturated radical R, R1, R2 or R3 must be present per silphenylene polymer of the formula (I). Where the sum of all organic radicals bonded to Si atoms through an oxygen atom, based on the sum of all Si-bonded radicals R, R1, R2 and R3 as 100 mol %, must not be more than 10 mol %. Where based on all bridging radicals Y as 100 mol %, at least 55 mol % of radicals Y are a di- to dodecavalent aromatic, alkylaromatic and cycloalkylaromatic radical.

Abstract: A process for refining crude molten silicon. The process includes oxidatively refining the crude molten silicon in the production of technical silicon. The crude molten silicon is admixed during the refining with a particulate mediator which has a minimum amount of metallic silicon of 8% by mass and also at least one or more of the elements H, C, O, F, Cl, Ca, Fe and Al. The particulate mediator is described by a characteristic number K which has a value of 0.03 to 6 mm?1 and is calculated using the formula K = 6 · ( 1 - ? m , M ) d 50 , M where d50,M is the particle size (diameter) at 50% of the mass undersize of the grading curve of the particulate mediator [mm] and the ?m,M is the mean effective porosity of the particulate mediator.

Abstract: The present disclosure relates to a method for preparing polyorganosiloxanes, comprising the following steps: a) reacting together a hydroxyl-terminated polysiloxane and a dialkoxysilane or an oligomer thereof in the presence of Catalyst 1, and b) reacting the product of Step a) with an endcapper in the presence of Catalyst 2 to form the polyorganosiloxane. According to this method, poly-organosiloxanes with an appropriate degree of the polymerization and viscosity are prepared by the polycondensation and equilibration reactions sequentially, and can significantly reduce the viscosity, and improve the flowability and thermal conductivity of the resulting silicone compositions, compared with other polysiloxanes at the same high thermally conductive filler loading.

Abstract: A defoamer or anti-foam formulation and a process for preparing the same. The process includes in a first step, preparing branched organopolysiloxanes (A) by irradiating organopolysiloxanes (X) of the formula (1) R13-a(R2O)aSi—[OSiR32]n—OSi(OR2)aR13-a ??(1). Where with high-energy radiation, the viscosity of the organopolysiloxanes (A) is at least 40% higher than the viscosity of the organopolysiloxanes (X). In a second step, the branched organopolysiloxanes (A) are treated with a filler (B) which is selected from precipitated and/or fumed silicas, and organopolysiloxane resins (C).

Abstract: A thermally conductive composition includes a component (A) that is a diorganopolysiloxane having an alkenyl group bonded to a silicon atom, a component (B) that is a diorganopolysiloxane having a hydrogen atom bonded to a silicon atom, a component (C) that is expandable graphite, a component (D) that is a thermally conductive filler, a component (E) that is an addition reaction catalyst, an organosilicon compound or an organosiloxane (also referred to as a silane coupling agent) that produces silanols by hydrolysis, and a condensation catalyst. The expansion rate (volume after high temperature exposure/volume before high temperature exposure) of a thermally conductive member obtained by curing the thermally conductive composition is 1.1 or less.

Abstract: Provided is a thermally conductive insulating silicone composition that has favorable thermal conductivity and dispensing properties, has favorable resiliency after curing, and can secure adhesion even under application of impact. Also provided is a method for manufacturing such a thermally conductive insulating silicone composition. The thermally conductive silicone composition is applied in a liquid state to a substrate, and contains: (A) a diorganopolysiloxane having an alkenyl group bonded to a silicon atom; (B) a diorganopolysiloxane having a hydrogen atom bonded to a silicon atom; (C) a thermally conductive filler; (D) a silicone resin having at least one alkenyl group within one molecule, with a number-average molecular weight of 1,000 or more; and (E) an addition reaction catalyst.

Abstract: A method of automatic packing of comminuted silicon includes providing an inner bag in a first shaping vessel, spreading out an opening of the inner bag and positioning the opening above a lip of a first filling funnel of a filling unit, and filling the inner bag with comminuted silicon. The comminuted silicon passes through the filling funnel into the inner bag. The inner bag is welded in a welding unit. The opening of the inner bag is folded together by inward folding of two opposite inner bag sides such that two inner bag edges formed by the folding-together are opposite and parallel to one another and form a fold with a channel. A vacuum welder is applied to the fold and welds the inner bag. The inner bag is transferred into an outer bag. The outer bag is welded.

Abstract: The invention relates to a 3D printing method for the layer-by-layer fabrication of objects using laser transfer printing, and to a 3D printing device for carrying out the method. According to the method, a printing compound (54) applied to a carrier cylinder (51) is irradiated with a laser (50), detached, and transferred to a base plate (27). The resulting printing compound layers are subsequently cured and the process repeated until the object is completely built up. Using said claimed method, objects can be printed from a variety of possible printing materials with high throughput (over 1 kg/h) without affecting the print quality.

Abstract: A process for preparing trimethylchlorosilane (M3) and methyltrichlorosilane (M1) by disproportionation of dimethyldichlorosilane (M2) in the presence of an Al2O3 catalyst is described herein. The dimethyldichlorosilane used is in the form of a silane mixture that includes 80-100% by weight of dimethyldichlorosilane (M2). The difference in content from 100% by weight includes M1 and M3.

Abstract: Stable preparations of composite particles based on organic polymer and inorganic particles contain, as the organic polymer, an addition polymer containing moieties derived from polymerization of an unsaturated carboxylic acid in addition to vinyl ester, (meth)acrylic ester, olefin, vinyl aromatic, and/or vinyl halide monomers.

Abstract: A method for producing polycrystalline silicon includes introducing a reaction gas, which in addition to hydrogen contains silane and/or at least one halosilane, into a reaction space of a gas phase deposition reactor. The reaction space includes at least one heated filament rod upon which by deposition silicon is deposited to form a polycrystalline silicon rod. During the deposition, the the morphology of the silicon rod is determined.

Abstract: A method for preparing isocyanatoalkylalkoxysilanes (S—I) of the general formula (6). Where in a first method step haloalkylalkoxysilane (S—H) of the general formula (7) is reacted with a metal cyanate (MOCN) and an alcohol (A) of the general formula (8), to form a carbamatoalkylalkoxysilane (S—C) of the general formula (9). In a second method step the carbamatoalkylalkoxysilane (S—C) is purified by distillation and in a third method step the isocyanatoalkylalkoxysilane (S—I) is generated from the silane (S—C) by a thermolytic alcohol elimination.

Abstract: Methods and devices for sorting silicon fragments. The method includes the steps of singulating the chunks in a singulating region and recording the projected area of a chunk in a 2D profile plane with at least one first measuring device. Recording at least one height information item above and/or below the 2D profile plane with at least one further measuring device. Calculating the size of the chunk from the projected area and the height information item and controlling at least one deflecting device as a function of the calculated size.

Abstract: A crosslinkable stabilized composition for a nonwoven substrate includes an aqueous dispersion of vinyl acetate-ethylene copolymers, a polyvinyl alcohol dispersion stabilizer, and a copolymer comprising maleic anhydride units or a copolymer comprising maleic acid units. The composition exhibits a free formaldehyde content of 5 ppm or less.

Abstract: A process for preparing multistage copolymers in the form of aqueous dispersions by multistage, radically initiated emulsion polymerization includes a first stage, second stage, and third stage. In the first stage, 20% to 75% by weight of vinyl acetate, optionally ethylene and optionally one or more further ethylenically unsaturated monomers are polymerized. In the second stage, in the presence of the polymer from the first stage, 1% to 25% by weight of vinyl acetate, 0.01% to 2% by weight of one or more ethylenically unsaturated silicon-functional monomers and optionally one or more further ethylenically unsaturated monomers are polymerized. In the third stage, in the presence of the polymer from the second stage, 5% to 40% by weight of one or more monomers selected from the group encompassing esters of acrylic acid, esters of methacrylic acid and vinyl aromatics and optionally one or more further ethylenically unsaturated monomers are polymerized.

Abstract: A process for dehydrogenating and methylating silanes. The process includes providing methyl chloride that is reacted with a silane selected from the group consisting of SiH4, H2SiMe2, H2SiMeCl, H3SiMe, H3SiCl and HSiMe2Cl, in the presence of at least one ammonium and/or phosphonium salt at a temperature in the range of 70-350° C.

Abstract: Nonwoven fiber webs are produced by spraying one or more aqueous binder formulations containing one or more polymers selected from the group of vinyl ester polymers and (meth)acrylic ester polymers, and in a separate step, spraying one or more aqueous silicone formulations containing one or more polysiloxanes, onto the surface of an airlaid nonwoven.