A paint composition of the present invention contains an aluminum pigment and a mica pigment. The content of the aluminum pigment is equal to or higher than the content of the mica pigment. The aluminum pigment has a specific surface area, determined by the BET method, of not more than 55000 cm.sup.2/g, an average thickness of not less than 0.3 μm, and an aspect ratio of not more than 50.

A paint composition of the present invention contains an aluminum pigment and a mica pigment. The content of the aluminum pigment is equal to or higher than the content of the mica pigment. The aluminum pigment has a specific surface area, determined by the BET method, of not more than 55000 cm.sup.2/g, an average thickness of not less than 0.3 μm, and an aspect ratio of not more than 50.

Provided is a dendritic silver-coated copper powder which is capable of effectively ensuring a contact, while having excellent electrical conductivity by having the surface coated with silver. A silver-coated copper powder according to the present invention is obtained by coating the surface of a copper powder 1, which is an assembly of copper particles 2 and has a dendritic form having a plurality of branches, with silver. Each copper particle 2, the surface of which is coated with silver, is an ellipsoid that has a breadth within the range of from 0.2 μm to 0.5 μm and a length within the range of from 0.5 μm to 2.0 μm. The average particle diameter (D50) of the copper powder 1, which is obtained by coating the surface of the assembly of the ellipsoidal copper particles 2 with silver, is from 5.0 μm to 20 μm.

Provided in one example herein is a three-dimensional printing method, comprising: (A) forming a layer comprising a comprising particles comprising a polymer and cavities between the particles, wherein the particles have an average diameter of between about 5 μm and about 250 ρm; (B) disposing a liquid suspension over at least a portion of the layer such that the liquid suspension infiltrates into the cavities, wherein the liquid suspension comprises a radiation-absorbing coalescent agent and nanoparticles having an average diameter of less than or equal to about 500 nm; (C) forming an object slice by exposing the infiltrated layer to a radiant energy, wherein the object slice comprises a polymeric matrix comprising the polymeric particles, at least some of which are fused to one another, and the nanoparticles within the polymeric matrix; and (D) repeating (A) to (C) to form the three-dimensional object comprising multiple object slices bound depth-wise to one another.

Provided in one example herein is a three-dimensional printing method, comprising: (A) forming a layer comprising a comprising particles comprising a polymer and cavities between the particles, wherein the particles have an average diameter of between about 5 μm and about 250 ρm; (B) disposing a liquid suspension over at least a portion of the layer such that the liquid suspension infiltrates into the cavities, wherein the liquid suspension comprises a radiation-absorbing coalescent agent and nanoparticles having an average diameter of less than or equal to about 500 nm; (C) forming an object slice by exposing the infiltrated layer to a radiant energy, wherein the object slice comprises a polymeric matrix comprising the polymeric particles, at least some of which are fused to one another, and the nanoparticles within the polymeric matrix; and (D) repeating (A) to (C) to form the three-dimensional object comprising multiple object slices bound depth-wise to one another.

Disclosed embodiments concern a composition comprising a diatom frustule and two or more photocatalytic nanoparticles dispersed on the surface of the frustule. Also disclosed are embodiments of a method for making the composition. The nanoparticles are dispersed such that they are separate and not in physical contact with each other. An average distance between the nanoparticles may be from greater than 0 nm to 100 nm. The nanoparticles may comprise a dopant material. Paint compositions comprising the diatom frustule compositions are also contemplated. The diatom frustule composition may be useful for removing and/or degrading volatile organic compounds, such as those present in the atmosphere.

Disclosed embodiments concern a composition comprising a diatom frustule and two or more photocatalytic nanoparticles dispersed on the surface of the frustule. Also disclosed are embodiments of a method for making the composition. The nanoparticles are dispersed such that they are separate and not in physical contact with each other. An average distance between the nanoparticles may be from greater than 0 nm to 100 nm. The nanoparticles may comprise a dopant material. Paint compositions comprising the diatom frustule compositions are also contemplated. The diatom frustule composition may be useful for removing and/or degrading volatile organic compounds, such as those present in the atmosphere.

The filter medium is a filter medium which uses a liquid containing oil and water as a separation target, and has a channel for the liquid. The filter medium includes a base constituting the channel, and one or more of nitrogen-containing fluorine compounds which are provided on at least a portion of a surface of the channel. The nitrogen-containing fluorine compound includes an oil-repellency imparting group and any one hydrophilicity imparting group selected from a group consisting of an anion type, a cation type, and an amphoteric type, in a molecule.

The filter medium is a filter medium which uses a liquid containing oil and water as a separation target, and has a channel for the liquid. The filter medium includes a base constituting the channel, and one or more of nitrogen-containing fluorine compounds which are provided on at least a portion of a surface of the channel. The nitrogen-containing fluorine compound includes an oil-repellency imparting group and any one hydrophilicity imparting group selected from a group consisting of an anion type, a cation type, and an amphoteric type, in a molecule.

The present invention is a copolymer containing, as essential structural units, unit A represented by Formula (1) and unit B represented by Formula (2):

##STR00001##

(wherein R.sup.1 and R.sup.4 each independently represent a hydrogen atom or a methyl group, and R.sup.2 and R.sup.3 each independently represent a hydrogen atom or a C1-20 hydrocarbon group, excluding cases where two or more groups of R.sup.1 to R.sup.3 are hydrogen atoms.)

##STR00002##

(wherein R.sup.5 represents a hydrogen atom or a methyl group, and R.sup.6 represents a group selected from the group consisting of C1-20 hydrocarbon groups optionally containing an oxygen atom, C1-20 alkoxy groups, hydrogen atoms, oxygen radicals and hydroxyl groups.)