A hydrogel includes: a partially or fully ionized cationic polymer and at least one selected from the group consisting of a partially or fully ionized anionic polymer and a low molecular weight compound having two or more anionic groups; or a partially or fully ionized anionic polymer and at least one selected from the group consisting of a partially or fully ionized cationic polymer and a low molecular weight compound having two or more cationic groups; and water. The hydrogel can be used for for producing clay with viscoelastic properties.

There is provided an apparatus and a method for producing a play compound and the play compound itself which, in one embodiment is a compound which sufficiently fluid to be pliable and is typically cold and slimy to the touch. The apparatus and a method provide a powder and liquid to a user, which can be a non-skilled person and thereby allow the mixing of the powder and liquid together by that person to form the play compound outside of a factory environment whilst ensuring that the play compound which is formed has the desired characteristics. Most typically the user which performs the mixing can be the end user, such as a child, who will play with the compound and so the formation of the play compound forms a new part of the play experience.

A composition comprising; a) at least one homopolymer or copolymer of vinyl acetate; and b) at least one softener.

There is provided an apparatus and a method for producing a play compound and the play compound itself which, in one embodiment is a compound which sufficiently fluid to be pliable and is typically cold and slimy to the touch. The apparatus and a method provide a powder and liquid to a user, which can be a non-skilled person and thereby allow the mixing of the powder and liquid together by that person to form the play compound outside of a factory environment whilst ensuring that the play compound which is formed has the desired characteristics. Most typically the user which performs the mixing can be the end user, such as a child, who will play with the compound and so the formation of the play compound forms a new part of the play experience.