WATER-DISPERSIBLE SHEET

• Main Authors: ISHINO Yoshiaki, WADAGAMI Kazuyo, MATSUMORI Yasuaki, KUSANO Eiji, KISHIMOTO Masaki, AOSHIMA Kento, KATSUMATA Kumiko
• Format: Patent
• Language: English; French; German
• Published: 09.09.2020
• Subjects: ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; ADHESIVES; CHEMISTRY; COLOUR PRINTING; DYES; IMPREGNATING OR COATING OF PAPER; LINING MACHINES; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; PAINTS; PAPER NOT OTHERWISE PROVIDED FOR; PAPER-MAKING; PERFORMING OPERATIONS; POLISHES; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; PRINTING; PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; PRODUCTION OF CELLULOSE; PULP COMPOSITIONS; STAMPS; TEXTILES; TRANSPORTING; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; TYPEWRITERS; USE OF MATERIALS AS ADHESIVES

The present invention provides a water-dispersible sheet with a suppressed time degradation of the tacky adhesiveness of the tacky adhesive layer, while maintaining the water dispersibility.The time degradation of the tacky adhesiveness of the tacky adhesive layer of a water-dispersible sheet can be suppressed, while maintaining the water dispersibility of the water-dispersible sheet, by using a paper substrate of the water-dispersible sheet with a multilayer structure, wherein one of the multilayer (inner layer) which is not in contact with a tacky adhesive layer and the other layer (surface layer) which is in contact with the tacky adhesive layer comprise independently a mixed pulp of a wood pulp and a refined pulp with α-cellulose content of 88% by weight or more, wherein the weight ratio of these layers and the beating degree of the mixed pulps are set in the specific ranges. Provided is a water-dispersible sheet comprising a paper substrate comprising an inner layer and at least one surface layer, wherein a tacky adhesive layer is installed on one of the surface layer (hereinafter referred to as "first surface layer"),wherein the first surface layer comprises a mixed pulp 1, which comprises a wood pulp and a refined pulp with α-cellulose content of 88% by weight or more, wherein the Canadian standard freeness of the mixed pulp 1 is from 450 to 600 ml CSF, the content of the wood pulp in the mixed pulp 1 is from 50 to 95% by weight, the inner layer comprises a mixed pulp 3, which comprises a wood pulp and a refined pulp with α-cellulose content of 88% by weight or more, wherein the Canadian standard freeness of the mixed pulp 3 is from 600 to 750 ml CSF, and the content of the wood pulp in the mixed pulp 3 is from 50 to 95% by weight.