A sheet manufacturing apparatus includes a mixing unit that mixes fibers and a composite in the atmosphere, a forming unit that deposits and heats a mixture mixed by the mixing unit to form a sheet; in which the composite is resin particles with at least a portion of a surface coated by inorganic fine particles, and an absolute value of an average charging amount of the composite is 40 μC/g or higher.

A method of and an arrangement for adding a chemical to an approach flow system of a fiber web machine by mixing of a retention chemical to a fibrous stock flowing in an approach flow system of a fiber web machine by a mixer (200) between the attenuator (16) and the headbox (18).

A method of and an arrangement for adding at least one additional stock component to an approach flow system (30) of a fiber web machine by mixing the at least one additional stock component to a fibrous stock such that the stock flow is equalized (50) and the at least one additional stock component is introduced to the stock flow by injection mixing (80).

A composite of the present disclosure includes a fiber, and starch, in which at least a part of the starch is fused to the fiber, and a weight-average molecular weight of the starch is 40,000 or higher and 400,000 or lower. A method for producing a molded product of the present disclosure includes a molding raw material preparing step of preparing a molding raw material containing a fiber and a starch that has a weight-average molecular weight of 40,000 or higher and 400,000 or lower, a humidifying step of humidifying the molding raw material, and a molding step of molding the molding raw material into a predetermined shape by heating and pressurizing the molding raw material.

A method of and an arrangement for adding at least one additional stock component to an approach flow system (30) of a fiber web machine by mixing the at least one additional stock component to a fibrous stock such that the stock flow is equalized (50) and the at least one additional stock component is introduced to the stock flow by injection mixing (80).

A method of and an arrangement for adding a chemical to an approach flow system of a fiber web machine by mixing of a retention chemical to a fibrous stock flowing in an approach flow system of a fiber web machine by a mixer (200) between the attenuator (16) and the headbox (18).

A process for the production of paper, board, and cardboard is disclosed. The process results in improved drainage and comprises adding to the wet end of a paper machine (a) microfibrillated cellulose and (b) a coadditive. The coadditive can be one or more of (1) a cationic aqueous dispersion polymer, (2) colloidal silica, (3) bentonite clay and (4) vinylamine-containing polymers or combinations thereof.

A process for the production of paper, board, and cardboard is disclosed. The process results in improved drainage and comprises adding to the wet end of a paper machine (a) microfibrillated cellulose and (b) a coadditive. The coadditive can be one or more of (1) a cationic aqueous dispersion polymer, (2) colloidal silica, (3) bentonite clay and (4) vinylamine-containing polymers or combinations thereof.

The present invention provides a method and system for measuring disintegration of a fibrous product. The method comprises disintegration of a sample of the fibrous product in an aqueous solution, optionally promoted by mechanical energy, passing the aqueous solution through a screen to obtain a permeate and retained fraction on the screen, and analyzing at least one parameter from the permeate for example by a gravimetric analysis, an optical analysis, an electrochemical analysis, a volumetric analysis, or combination thereof. Advantages include adjustability, speed, and high correlation with actual flushability or repulpability of the fibrous product, and utility in a process for manufacturing a fibrous sheet exhibiting controlled disintegration, such as a flushable or repulpable fibrous sheet.

A process for the production of paper, board, and cardboard is disclosed. The process results in improved drainage and comprises adding to the wet end of a paper machine (a) microfibrillated cellulose and (b) a coadditive. The coadditive can be one or more of (1) a cationic aqueous dispersion polymer, (2) colloidal silica, (3) bentonite clay and (4) vinylamine-containing polymers or combinations thereof.