A platinum organosiloxane complex is prepared by a process including combining A) a platinous halide; B) a ketone; C) an enone additive distinct from any other starting materials or rearrangement products thereof; and D) a polyorganosiloxane having, per molecule, 2 to 4 silicon bonded terminally unsaturated hydrocarbon groups having from 2 to 6 carbon. The platinum organosiloxane complex prepared by the process is useful as a hydrosilylation catalyst.

A silicone-polyether copolymer has the formula X.sub.gY, where each X is an independently selected silicone moiety having a particular structure, Y is a linear or branched polyether moiety, and subscript g is on average more than 1. A method of preparing the silicone-polyether copolymer comprising reacting a polyether compound and an organosilicon compound in the presence of a hydrosilylation-reaction catalyst. A sealant is also disclosed, the sealant comprising the silicone-polyether copolymer and a condensation-reaction catalyst.

A metatitanic acid particle includes a metal having a hydrocarbon group, which is bonded to a surface of the metatitanic acid particle through an oxygen atom, and absorbs light having a wavelength of 450 nm and light having a wavelength of 750 nm, wherein an element ratio C/Ti between carbon C and titanium Ti in a surface of the metatitanic acid particle is from 0.3 to 1.2, and a reduced amount of C/Ti on the surface of the metatitanic acid particle before and after irradiation with an ultraviolet ray having a wavelength of 352 nm and at an irradiation intensity of 1.3 mW/cm.sup.2 for 20 hours is from 0.1 to 0.9.

A silicone-polyether copolymer has the formula X.sub.g[Z.sub.jY.sub.o].sub.c, where each X is an independently selected silicone moiety having a particular structure, each Y is an independently selected polyether moiety, each Z is an independently selected siloxane moiety, subscript c is from 1 to 150, subscript g is >1, and each subscript j and o are independently >0 and <2, with the proviso that j+o=2 in each moiety indicated by subscript c. A method of preparing the silicone-polyether copolymer is also disclosed, and comprises reacting a polyether compound, a chain extending organosilicon compound, and an endcapping organosilicon compound in the presence of a hydrosilylation catalyst. A sealant is also disclosed, the sealant comprising the silicone-polyether copolymer and a condensation-reaction catalyst.

A silicone-polyether copolymer has the formula (X-D.sup.2).sub.g-Y, where each X is an independently selected silicone moiety having a particular structure, D.sup.2 is a divalent hydrocarbon group, subscript g is greater than 1, and Y is a linear or branched polyether moiety. A method of preparing the silicone-polyether copolymer comprising reacting a polyether compound and an organosilicon compound in the presence of a hydrosilylation-reaction catalyst. A sealant is also disclosed, the sealant comprising the silicone-polyether copolymer and a condensation-reaction catalyst.

A platinum organosiloxane complex is prepared by a process including combining A) a platinous halide; B) a ketone; C) an enone additive distinct from any other starting materials or rearrangement products thereof; and D) a polyorganosiloxane having, per molecule, 2 to 4 silicon bonded terminally unsaturated hydrocarbon groups having from 2 to 6 carbon. The platinum organosiloxane complex prepared by the process is useful as a hydrosilylation catalyst.

An isocyanate-functional silicone-polyether copolymer having a particular structure is disclosed. A method of preparing the isocyanate-functional silicone-polyether copolymer is also disclosed, the method comprising reacting a polyether compound and an organosilicon compound to give the isocyanate-functional silicone-polyether copolymer. A silicone-polyether-urethane copolymer formed therewith, as well as a method of preparing the silicone-polyether-urethane copolymer, are also disclosed. Sealants comprising the isocyanate-functional silicone-polyether copolymer and/or the silicone-polyether-urethane copolymer are further disclosed.

A silicone-polyether copolymer has the formula X.sub.gY, where each X is an independently selected silicone moiety having a particular structure, Y is a linear or branched polyether moiety, and subscript g is on average more than 1. A method of preparing the silicone-polyether copolymer comprising reacting a polyether compound and an organosilicon compound in the presence of a hydrosilylation-reaction catalyst. A sealant is also disclosed, the sealant comprising the silicone-polyether copolymer and a condensation-reaction catalyst.

A silicone-polyether copolymer has the formula XY, where X is a silicone moiety having a particular structure and Y is a polyether moiety. An isocyanate-functional silicone-polyether copolymer formed therewith is also disclosed. Further, a silicone-poly-ether-urethane copolymer formed with the isocyanate-functional silicone-polyether copolymer is disclosed. Related methods of preparation as well as sealants and cured products thereof are further disclosed.

A filter includes resin particles and photocatalyst particles having absorption at wavelengths of 450 nm and 750 nm in the visible absorption spectrum. The photocatalyst particles are present on the surface of the resin particle.