Acid-free paper - Wikipedia,
Paper made from wood-based pulp that has not had its lignin removed goes yellow and
deteriorates over time. When exposed to light and/or heat, the molecules in the acidic
paper will break down even faster. It was only in the 1930s that the effects of wood-pulp
paper became known, when William Barrow (a librarian) published a report about the
deterioration of acidic paper in the libraries. For fear of the gradual disintegration of written
materials, measures have been taken to improve the quality of paper.
從木質紙漿作成的紙張，若是沒有去除木質素，在時間久了以後會變黃，紙質惡化。當暴露在
光線和熱源下的時候，酸性紙的分子會更快速的分解。這種圖書館裡的酸性紙質惡化的木質紙
的效應，是在1930年由一個圖書館員William Barrow發展的報告中為人所知，由於書寫紙張可
能瓦解的疑慮，己有採取種種研究,量測來改善紙張的品質。
During production, acid-free paper may be treated with a mild base (usually calcium or
magnesium bicarbonate) to neutralize the natural acids occurring in wood pulp, and it may
also be buffered to prevent the formation of additional acids (as may develop from the
application of sizing).
在生產過程中，可能使用一種較溫和的基底處理（通常是鈣，鎂碳酸鹽），以中和在木漿中的
酸性，也可以作為在額外的酸形成時的緩衝｛如在調整紙張大小尺寸時所形成的酸｝。
The bicarbonate is added in excess, to supply the paper with an alkaline reserve to provide
protection from further attack by acids remaining in the paper or supplied by the environment
(e.g. atmospheric sulfur dioxide).The bicarbonate during drying loses carbon dioxide and
water and is converted to calcium carbonate or magnesium carbonate. on order for paper to
last at least 100 years it must have an alkaline reserve of 2% or more.
碳酸鹽通常會被多量添加，可提供紙張儲存鹼性，以提供紙張提供保障進被紙張中剩餘的酸性或
環境（如大氣二氧化硫 ）中的酸性進一步的攻擊。在乾燥的過程中，紙張會流失二氧化碳與水份
，而碳酸鹽類會轉化成碳酸鈣或碳酸鎂，為了要使紙張能夠至少有100年以上的壽命,紙張中至少
要含有2%以上的鹹性儲存。
Today, much of the commercially produced paper is acid-free, but this is largely the result
of a shift from china clay to (cheaper) chalk as the main filler material in the pulp: chalk reacts
with acids, and therefore requires the pulp to be chemically neutral or alkaline. The sizing
additives mixed into the pulp and/or applied to the surface of the paper must also be acid-free.
今天，大部份的商業生產的紙張是無酸紙，在調整紙漿比例使用的紙漿添加劑與/或使用在紙張表
面的添加劑也必需是無酸性的。
Alkaline paper has a life expectancy of over 1,000 years for the best paper and 500 years for
average grades. The making of alkaline paper has several other advantages in addition to
the preservation benefits afforded to the publications and documents printed on it. Because
there are fewer corrosive chemicals used in making alkaline paper, the process is much easier
on the machinery, reducing downtime and maintenance, and extending the machinery's useful
life. The process is also significantly more environmentally friendly. Waste water and byproducts
of the papermaking process can be recycled; energy can be saved in the drying and refining
process; and alkaline paper can be more easily recycled.
最好的鹼性紙張有超過1000年的預期和500年的平均壽命，製作鹹性紙除了良好保存印刷品之
外，製作鹹性紙除了良好保存印刷品之外，還有其他的好處與優點。因為，製作鹹性紙的過程
中，使用較少具腐蝕性的化學物質，製程對於製作機械較為友善與容易，可以減低機械停機，
維修的時間，延長機具壽命。此製程也顯著地對於環境較為友善，廢水和副產品的造紙過程中
可以回收，在乾燥和優化進程中，可以節省能源，且鹼法紙可以更容易回收。作者: garycpim 时间: 2012-6-28 15:55
又查了一下，宣纸的制作工艺中需要石灰腌制蒸煮，增加了碱性。宣纸的PH值在8.3左右，比一般的纸要高，所以寿命据说也可以达到1050年。作者: 飞猫 时间: 2012-6-28 15:56
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