A method for manufacturing a printing paper for decorative boards is provided. The method includes the processes of: applying a resin-containing liquid comprising at least one of a resin and a resin precursor to a base paper for decorative boards; forming a print layer on or in the base paper which is not dried after the resin-containing liquid is applied thereto; and solidifying a liquid contained in the base paper having the print layer.

A friction paper including filler, para-aramid pulp, and resin, characterised in that the para-aramid pulp includes 0.1 to 10 wt. % of polyvinyl pyrrolidone (PVP), the paper having a grammage in the range of 100 to 800 g/m2. It has been found that the use of a PVP-containing para-aramid pulp leads to improved friction performance as compared to the use of para-aramid pulp not containing PVP. Effects obtained include improved friction properties, improved strength properties, and improved filler retention.

A friction paper including filler, para-aramid pulp, and resin, characterised in that the para-aramid pulp includes 0.1 to 10 wt. % of polyvinyl pyrrolidone (PVP), the paper having a grammage in the range of 100 to 800 g/m2. It has been found that the use of a PVP-containing para-aramid pulp leads to improved friction performance as compared to the use of para-aramid pulp not containing PVP. Effects obtained include improved friction properties, improved strength properties, and improved filler retention.

A preparation method of tea residue fiber raw materials includes steps of (1) sun-drying tea residues, crushing the sun dried tea residues, and treating them with concentrated hydrochloric acid and a strong base in succession; (2) extracting water from the treated tea residues to obtain tea polyphenols and pulp respectively, cooking the pulp, and then pressing and dehydrating it to obtain coarse pulp; (3) sequentially grinding and sieving the pulp, and beating it; and (4) adding -cyclodextrin, carboxymethylcellulose sodium, and reinforced starch after the beating, adjusting the pH to 7-8, diluting, adding the tea polyphenols obtained in the second step, stirring uniformly, pressing and dehydrating, and drying to obtain the tea residue fiber raw material.

A preparation method of tea residue fiber raw materials includes steps of (1) sun-drying tea residues, crushing the sun dried tea residues, and treating them with concentrated hydrochloric acid and a strong base in succession; (2) extracting water from the treated tea residues to obtain tea polyphenols and pulp respectively, cooking the pulp, and then pressing and dehydrating it to obtain coarse pulp; (3) sequentially grinding and sieving the pulp, and beating it; and (4) adding -cyclodextrin, carboxymethylcellulose sodium, and reinforced starch after the beating, adjusting the pH to 7-8, diluting, adding the tea polyphenols obtained in the second step, stirring uniformly, pressing and dehydrating, and drying to obtain the tea residue fiber raw material.

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.

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 method is for producing a wet-running friction paper, at least containing a fiber fraction consisting of at least one type of fiber, a fraction of at least one filler, and a fraction of a binder based on phenol resin. The fiber fraction, the filler fraction and the binder dissolved as a phenolate solution are processed together in a paper production process to form a pulp, and the binder is subsequently precipitated by means of a precipitating agent, preferably diluted sulfuric acid, and the pulp applied to a long screen is dried and cured while the temperature is raised.

A method is for producing a wet-running friction paper, at least containing a fiber fraction consisting of at least one type of fiber, a fraction of at least one filler, and a fraction of a binder based on phenol resin. The fiber fraction, the filler fraction and the binder dissolved as a phenolate solution are processed together in a paper production process to form a pulp, and the binder is subsequently precipitated by means of a precipitating agent, preferably diluted sulfuric acid, and the pulp applied to a long screen is dried and cured while the temperature is raised.

An aramid paper suitable for use in electronic applications which has a density of 0.20-0.65 g/cm3 and a grammage of 30-280 g/m2, which paper comprises 10-40 wt. % of aramid shortcut with a linear density of 2.6 dtex or lower and a length of 0.5-25 mm and 10-90 wt. % of aramid fibrid, wherein the aramid shortcut comprises at least 70 wt. % para-aramid shortcut and the aramid fibrid including at least 70 wt. % para-aramid fibrid. It has been found that the use of a paper with the above properties in electronic applications ensures a low CTE in combination with good homogeneity and a good dimensional stability resulting from good resin adhesion and penetration. Use of the aramid paper in a composite sheet including at least one layer of aramid paper and a resin, or in a substrate board for electronic applications.