Sheet

SUBJECT of the Invention This invention makes it a subject to provide the microfibrous cellulose containing sheet|seat excellent in the weather resistance. PROBLEM to be solved This invention is a sheet|seat in which a fiber width contains fibriform cellulose 1000 nm or less， Comprising: Fibriform cellulose has phosphorus oxo-acid group， Let the 1st dissociation acid amount in fibriform cellulose be A1， When the total dissociation acid amount in fibriform cellulose is made into A2， they are the values 0.61-1.00 of A1/A2， YI increase rate computed by the following formula is related with the sheet|seat which is 1500 % or less. Yellowness [ of the sheet|seat of YI increase rate (%)=(Yellowness of the sheet|seat of yellowness-pre-heating of the sheet|seat after a heating) / pre-heating ] x100 In said Formula， the yellowness of the sheet|seat after a heating is the yellowness measured based on JISK7373， after hot-pressing a sheet|seat for 1 minute at 180 degreeC and 0.5 Mpa， The yellowness of a pre-heating sheet|seat is the yellowness measured before hot press based on JISK7373. SELECTED DRAWINGS Absence [FIG. 1] [MAT_IMAGE 000006]

**发明技术主题**
本发明旨在提供一种具备优异耐候性的含微纤维纤维素片材。
**所要解决的技术问题**
本发明涉及一种片材，其包含纤维宽度不大于1000 nm的纤维状纤维素；该纤维状纤维素带有含氧磷酸基团，设其第一解离酸量为A₁、总解离酸量为A₂，则A₁/A₂的取值范围为0.61~1.00；通过下述公式计算得到的黄变增量率不超过1500%。
黄变增量率(%) = (加热后片材黄度指数 - 预热前片材黄度指数) / 预热前片材黄度指数 × 100
上述公式中，加热后片材黄度指数指将片材在180℃、0.5 MPa条件下热压1分钟后，依据JIS K7373标准测得的黄度指数；预热前片材黄度指数指热压前依据JIS K7373标准测得的黄度指数。
**选定附图**
无[附图1] [MAT_IMAGE 000006]