A method for deinking recycled paper, including a pulping step, and then a flotation step, which includes introduction of at least one dispersant of the polyacrylate type, representing from 0.05 to 3.5 wt % of the mineral fillers of the recycled paper. A specific dispersant is used during the flotation step of the method for deinking recycled paper.

A process for the deinking of a coated paper or paperboard is disclosed, the process comprises a step of providing a coating layer comprising a calcium- or magnesium-exchanged clay which is deposited on the paper or paperboard before the ink layer. In a further step said calcium- or magnesium-exchanged clay is activated and the paper is subsequently treated with water.

Provided are a pitch-formation suppressor and the like which can be widely applied independently of the substance that causes a pitch and of the situation to generate a pitch in a paper manufacturing process, and which can effectively suppress and prevent the troubles due to the pitch, such as foreign spots and defects in a paper, breakage of a paper, and lowering of workability. This pitch-formation suppressor comprises an alkaline solution in which a phenol resin and/or a modified phenol resin is dissolved, or an acid solution in which a phenol resin and/or a modified phenol resin is dissolved.

A pollen paper formed from a plurality of pollen microgels, which paper is dimensionally locked for use in the generation of conventional printed matter. It is possible to remove the printed subject matter from the pollen paper by a process that involves immersing the pollen paper into an alkaline bath, then removing the water through immersing it in a dehydrating bath and finally dimensionally locking the paper by immersing it in an acidic bath.

Disclosed herein is a hygromorphic composite material comprising a moisture-active pollen paper substrate formed from a plurality of pollen microgel particles, and at least one moisture-inactive layer applied onto the top and/or bottom surface of the moisture-active pollen paper substrate with a pattern that causes the hygromorphic composite material to change its shape in a pre-determined manner due to a change in relative humidity of its ambient environment. Also disclosed herein is a method of forming the hygromorphic composite material.

Provided is a method for producing paper and a pitch removal agent that can remove pitch efficiently. A pitch removal agent having an average polymerization degree of 300 to 2500, a saponification index of 70 to 88 mol % and satisfying, when the absorbance at a wavelength of 490 nm is designated as y (Abs) and the saponification index as x (mol %), the Numerical Formula (A) below is added to a pulp slurry during production of paper using waste paper in the step of deinking the waste paper by floatation and/or a step earlier:
y=0.0297x+b(A) (wherein, 70x88 and 2.80b3.03).

A processing device, a sheet manufacturing apparatus, a processing method, and a sheet manufacturing method that suppress damage to a substrate when removing color material from the substrate, and are useful for recycling the substrate after color material is removed, are provided. A processing device has a color material removal device including at least one discharge nozzle configured to discharge particles containing cellulose to a substrate holding color material, and remove the color material from the substrate. The color material removal device preferably has a double-walled conduit construction having an internal conduit and an external conduit in which the internal conduit is inserted, at least one of an opening to the internal conduit and an opening to the external conduit functioning as the discharge nozzle.

A processing device has a fibrillation portion fibrillating fiber-containing materials containing fibers in the air, a particle supply portion supplying particles having Mohs' hardness of 2 or more and 5 or less to the fiber-containing materials during or after the fibrillating at the fibrillation portion for collision of the particles and the fiber-containing materials, and a particle removal portion removing the particles from the fiber-containing materials to which the particles are supplied.

A process for the deinking of a coated paper or paperboard is disclosed, the process comprises a step of providing a coating layer comprising a calcium- or magnesium-exchanged clay which is deposited on the paper or paperboard before the ink layer. In a further step said calcium- or magnesium-exchanged clay is activated and the paper is subsequently treated with water.

Apparatus (200) for the treatment of one or more substrates comprising a treatment chamber configured to receive a liquid medium and one or more substrates; a supply of a treatment gas comprising ozone; and one or more conduits to convey said treatment gas to a bubble generator (41) wherein said bubble generator is operable to form bubbles of said treatment gas in said liquid medium, wherein the apparatus comprises a multiplicity of solid particles (46). A method of treating one or more substrates, the method comprising agitating said one or more substrates in a treatment formulation comprising a multiplicity of solid particles, a liquid medium and bubbles of ozone.