<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31436717</termId><termName>acid-free paper</termName><termType>PT</termType><termNote><![CDATA[ Paper that contains no free acids, thus providing greater permanence and durability; the term does not necessarily imply that the paper is alkaline-buffered. Acid-free paper is typically produced from cotton linters, rags, esparto grass, or chemical wood pulp which minimizes the potential for acid and/or lignin in the pulp. Acid-free paper may also contain a buffering material to maintain a pH in the neutral to slightly alkaline range. This helps scavenge any acidic materials formed by bleaching residues, sizes, degradation products, or air pollutants. ]]></termNote><termCreatedDate>2026-03-30 20:57:45</termCreatedDate><relation><relationType>UF</relationType><termId>31436718</termId><termName>paper, acid-free</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31436719</termId><termName>permanent paper</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31410914</termId><termName>paper by composition or origin</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31301520</termId><termName>archival quality</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31436738</termId><termName>wood-free paper</termName><termType>PT</termType></relation></term>  </Zthes>