This Technical Specification defines test methods and minimum requirements for paper deacidification processes regarding their effectiveness and consistency.
It is applicable for all large scale processes which offer deacidification of acid documents made of printed or hand-written paper.
Possible negative side effects of deacidification processes on the treated objects are not the subject of this Technical Specification. However, some general recommendations for how to cope with these side effects are given in Annex A.
It is not specified either, which types of paper objects can be treated by large scale deacidification methods. Whatever currently available deacidification method is used, some objects might be excluded from treatment to avoid mechanical damage to paper and bindings or other unwanted side effects. The provider of the deacidification treatment should inform the customer about the limitations of the chosen method.
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5351:2010, Pulps — Determination of limiting viscosity number in cupri-ethylenediamine (CED) solution
ISO 5630‑5:2008, Paper and board — Accelerated ageing — Part 5: Exposure to elevated temperature at 100 degrees C
ISO 6588‑1, Paper, board and pulps — Determination of pH of aqueous extracts — Part 1: Cold extraction
ISO 9184‑1, Paper, board and pulps — Fibre furnish analysis — Part 1: General method
ISO 9184‑4, Paper, board and pulps — Fibre furnish analysis — Part 4: Graff “C” staining test
For the purpose of this document, the following terms and definitions apply.
artificially induced ageing under laboratory condition by increasing temperature and sometimes changing humidity or exposure to light in order to accelerate chemical reactions in paper like hydrolysis or oxidation to simulate processes usually occurring under natural condition but at a much slower speed
average number of anhydroglucose units (monomers of cellulose) in the cellulose macromolecule
neutralization of the organic and inorganic acids in the paper and deposit of an alkaline reserve as buffer against any subsequent acidic activity on paper
value obtained in a water extract after the paper has been extracted under defined condition.
Note 1 to entry: Value measured with a glass electrode immersed in a definite quantity of water in which paper is dispersed in small pieces.
common logarithm of the number of double folds required to cause rupture in a strip of paper
securing an operation according to preset parameters determined at processed objects
paper with characteristics defined in this Technical Specification, which is deacidified together with original documents and then analysed
homogeneous distribution of the alkaline reserve and pH across the entire sheet and within whole book blocks
4 Principle 原则
Specified uniform test papers are treated together with customer’s documents in a deacidification process. Afterwards, the test papers are examined using standardized test methods. The test papers are acidic and similar in their properties to common paper qualities produced in the period from around 1870 onwards. The usage of such papers ensures reliable results and allows comparing different batches, deacidification methods and treatment plants.
NOTE It is to be emphasized that successful tests according to this Technical Specification cannot guarantee that all documents treated in the process are deacidified to the same degree as the test papers. The result of a deacidification treatment strongly depends on the properties of the treated object, such as porosity, thickness, sizing, coating and acidity of the paper, etc. Therefore, it is impossible to guarantee that certain pH levels and alkaline reserve amounts are achieved in each object by the deacidification treatment. A passing of the tests means, however, that there is a high percentage of successfully treated objects.
5 Requirements 要求
5.1 General / 总则
This Technical Specification defines test methods for “process validation” (initial testing) and “routine monitoring”. Process validation is used to prove that a technique fulfils its defined purpose. Routine monitoring is used to check that the effectiveness determined by process validation is being achieved in the course of the actual work. Routine monitoring, therefore, is based on process validation.
For “process validation”, extended test procedures should be carried out before and after accelerated ageing of the samples, including measurements of pH value, alkaline reserve, uniformity of deacidification and degree of polymerisation.
For “routine monitoring”, alkaline reserve of the test papers is examined.
5.2 Sampling 样品
5.2.1 Material 材料 / 原料
Both process validation and routine monitoring are performed using samples of test paper, some of which are deliberately not subjected to the deacidification process serving as a reference.
5.2.2 Procedure 过程控制
All samples should be examined within four weeks after treatment has been completed (including post treatment measures).
Before the paper is examined, any loose residues occurring as a side effect of the deacidification process should be removed by brushing.
5.3 Process validation 工艺验证
5.3.1 Frequency of sampling 采取样品的频率
A complete process validation is required every four years and, additionally, following
— changes to the process technology, 工艺技术更新/改变的部分
— changes of chemical components or their supplier, 供应商或者化学配方的变化
— changes of the test paper for routine monitoring. 用于常规监测的测试纸的变化
The process validation is valid for all treatment devices of a production site that use the same process and technology.
5.3.2 Sample quantities and preparation of samples 样品的数量和准备
The process validation is performed using identical test papers (i.e. same production batch). A quantity of 32 (+4, if folding endurance is included) test sheets, size A5 or larger, is needed for the necessary testing (see Table 2) of one treated sample set. Four treated sample sets are necessary for the process validation. The untreated sample set included, the sum of test sheets for one complete process validation is therefore 148 (+20, if folding endurance is included).
工艺验证是通过使用相同测试纸进行(即同一生产批次的测试纸)。根据测试表，需要32张测试纸(+ 4,如果也进行耐折度测试),根据测试需求纸张A5大小或更大(见表2)集体进行处理。进行工艺验证必须要准备4套处理过的样品。包括未经处理的样本集,一组完整工艺验证的需要的测试纸张数量是148张(+ 20,如果也进行耐折度测试)。
For batch processes, the test papers should be placed into bound volumes which are thicker than 3 cm and feature a size of at least A5. For the first sample set, 32 (+4) test papers are placed evenly throughout the bound volume starting from page number 10.
The test papers should be centred vertically and placed as close to the spine as possible. The test papers should not extend outside the book block. The second sample set is prepared the same way, but placed in a different position in the treatment chamber. The third and fourth sample set should be treated on another day, and if applicable, in another treatment device. The positions of the samples in the chamber should be documented adequately.
NOTE Service providers can supply a constructional drawing of the deacidification device with the report and mark the positions of the books containing the test papers.
For continuous processes, the test papers of one sample set should be treated alternating with sheets of original items. After further treatment of 100 sheets of original items, the second sample set should be treated to the same pattern as the first. The third and fourth sample sets should be treated according to the first two sample sets, but on a different day, and, if applicable, in another device.
5.3.3 Test methods and minimum requirements 测试方法和最低要求
184.108.40.206 Accelerated ageing 加速老化
Perform accelerated ageing of 10 (+2) test sheets of each of the four sample sets and 10 (+2) untreated test sheets as described in ISO 5630‑5:2008, Clause 4 to 9.2.
根据ISO 5630‑5:2008, Clause 4 to 9.2， 4组测试样品中10（+2）张测试纸进行加速老化，未处理的10（+2）张不进行老化处理
Test tubes selected for this study shall be perfectly gas-tight and large enough to accommodate paper strips pre-cut for further measurements. It is required to perform aging for all samples simultaneously, in the same laboratory oven, using one type of a glass tube for all samples.
NOTE To ensure perfect airtightness of testing tubes, the following steps could be taken:
— original tube caps supplied with glass tubes could be exchanged for caps made of material with higher resistance to mechanical and thermal stresses (e.g. polyphenylsiloxane);
注意： 为确保试管的绝对密封， 请按以下步骤操作：
— sealing material – PTFE or silicone gaskets and o-rings should be avoided, fluoroelastomers are advisable (e.g. Viton);
-- 密封材料 - PTFE 或者silicone gaskets and o-rings这三种要杜绝使用，推荐使用氟橡胶 （如：Viton)
— tightening of the tube with the use of the dynamometric wrench equipped with a tube cap holder, to ensure good repeatability of obtained sealing.
220.127.116.11 pH value pH值
The pH value has to be measured in an aqueous extract as described in ISO 6588-1.
The average results and the average and the relative standard deviations should be given for treated paper with and without ageing, and the results should be expressed to two significant digits.
The measured pH of the paper following deacidification has to be higher than 6,5 (before accelerated ageing).
NOTE 1 The pH value of an aged sample will normally be lower compared to those of the non-aged sample. For a given paper, ageing after deacidification should only lead to a small reduction of its pH value. It is possible that the pH value measured after accelerated ageing will level out at around 6,5, even though an alkaline reserve is still present. This is particularly true of the pH value on the paper surface which is usually one unit lower than the pH value of the cold extract. Under these conditions, however, this kind of paper can still be described as being neutral.
The pH value discussed here applies solely to the described test papers. If original papers are examined as well, special agreements on an acceptable final pH value should be reached with the customer, as the achieved pH value depends very much on the original composition of the paper.
NOTE 2 In addition to this measurement of aqueous extract pH value, measurements of surface pH value are sometimes performed. The surface pH measurement is a faster method compared to extraction pH measurement to judge the pH value of a paper. If applied correctly (see Reference ), surface pH measurements also allow onsite measurements of original books and documents in libraries and archives and can also be used to follow the stability of deacidification on a longer timescale. However, surface pH measurement has its limits. It works well for acidic to neutral papers and also gives reasonable data until about pH 9. Usually, surface pH measurement has been successfully used with immersion treatments. Surface pH measurement may fail to give reliable results when larger amounts of alkaline reserve deposits are present at the paper surface and the solubility limit is reached.
18.104.22.168 Alkaline reserve 碱性储备量
Determine the quantity of alkaline reserve of each of the four sample sets as described in ISO 10716. For determination of the dry matter content, it is in deviation to ISO 10716 sufficient for the purpose of this Technical Specification to weigh about 1 g to the nearest 0,001 g.
The results, the average and the relative standard deviation should be given for treated paper with and without ageing, and the results should be expressed to two significant digits.
The minimum alkaline reserve is 0,5 mass % expressed as MgCO3.
NOTE Part of the total amount of alkaline substance applied to the paper by deacidification treatment is chemically converted (“consumed”) by the neutralization reaction, and the remainder is the “alkaline reserve”. The alkaline reserve ensures that the paper is resistant to acids acting upon it due to environmental influences or degradation reactions occurring after the deacidification process.
22.214.171.124 Uniformity of deacidification 脱酸的均匀性
The uniformity of deacidification is measured by quantitative determination of the alkaline reserve, expressed as mass % MgCO3, at six different segments of a treated sample. Figure 1 shows the cutting pattern for the segments.
Figure 1 — Segments for the determination of alkaline reserve for uniformity test
表1 -- 用于碱性储备量均匀性测试的切片
As one A5 sheet of test paper is not sufficient for analysing uniformity due to the limited sample amount (for alkaline reserve 1 g of sample is required per data point), the measurement of the alkaline reserve of the six treated paper samples is carried out as described in ISO 10716, with the following amendments: Three A5 test paper sheets are cut into six rectangular, numbered segments of equal size according to the pattern shown in Figure 1. Then, the three pieces with same numbers are put together, divided into small pieces as described in ISO 10716, and the resulting pile is mixed well. About 1 g of pieces is weighed and treated as described in ISO 10716.
由于一张A5的测试纸的碱性储备量太少不够做均匀性的分析（碱性储备所需的量为：1 g /数据点),把3张A5测试纸张切成六个矩形, 根据ISO 10716所述对6个脱酸样本进行碱性储备量的测量,如图1所示把样品编号（1-6），标出每张纸上的碱性储备量。然后,如ISO 10716所述把三张具有相同的碱性储备量的纸张放在一起,分成小块，再混合起来。达到ISO 10716的标准。
Alkaline reserve measured for each section should be not less than 0,5 % by weight calculated as MgCO3 equivalent. In addition, the relative standard deviation of the six individual measured values is required to be less than 30 %. The lower the deviation calculated in this way, the better the uniformity of deacidification.
NOTE 1 The results of these measurements describe the distribution of the added alkaline substance over the entire surface area of the sheet of paper, not its homogeneous distribution across its thickness/cross section. For the latter, no standardized routine methods are available.
NOTE 2 Some alternative methods exist which are able to address the uptake of deacidification reagent, in most cases, the concentration of cations is analysed. However, these methods do not suffice as a full displacement of alkaline reserve determination, as most of them are not fully comparable with the actual amount of alkaline reserve. However, to estimate whether mass deacidification was homogeneous they can serve as alternative.Potential methods are based on inductively coupled plasma optical spectrometry (ICP/OES) after the alkaline reserve was extracted by acid from the paper segments, X-ray-Fluorescence scanning or FTIR/NIR and other methods which reliably report the uptake of deacidification reagent.
注2：当下也有其他检测均匀性的方法,这些方法是通过是分析阳离子的浓度检测。然而,这些方法还是有缺陷的,因为大部分用这种方式测出的碱性值没有办法与实际量做比较。当然,这些可以也可以作为检测脱酸均匀性的方法。潜在的方法是基于电感耦合等离子体光学光谱(ICP / OES)碱性储备量,x射线荧光扫描或红外光谱/近红外光谱等方法,这些方法依赖于碱性残留量的报告。
126.96.36.199 Degree of polymerisation 聚合度
A pretreatment to remove the excess of alkaline reserve in the sample has to be performed as follows:
Disintegrate 1 g to 3 g of paper sample in a mixer for less than 30 s directly in 1,5 L, 0,1 M HCl at room temperature (for 3 g of paper sample with 2 % alkaline reserve this corresponds to >200 fold excess of acid when 1,5L are used). Rinse the sample thoroughly with water until washing water is neutral. Dry sample at room conditions according to ISO 5351:2010, Clause 8. The sample preparation should be adapted to the ingredients of the deacidification process.
在常温下，把混合纸样品分解到1 g至3 g放在1 5 L,0 1 M盐酸里浸泡30秒(3 g纸样品与2%碱性储备对应> 200倍过量的酸1时,使用5 L)。冲洗样品直到冲洗水变成中性的。根据ISO 5351:2010 条款8 在常温下干燥样品。根据脱酸程序准备合适的样品。
NOTE 1 ISO 5351:2010, Clause 8 requires 10 g of material, but 1 g is sufficient for the DP sample preparation in the present case. Determine the degree of polymerisation by measuring the viscosity average with CED as described in ISO 5351 before and after accelerated ageing. For determination of the dry matter content, it is in deviation to ISO 5351 sufficient for the purpose of this Technical Specification to weigh about 1 g to the nearest 0,001 g. The average results of the limiting viscosity number should be given for treated and untreated papers with and without ageing, and the results should be expressed in millilitres per gram.
根据ISO 5351:2010 条款8，要准备10g材料，现在的情况下，做DP（聚合反应）测试样品只需要准备1g就够了。根据ISO 5351要求对样品加速老化前后通过测量CED（内聚能密度）来检测聚合程度。对于干物质含量检测，根据ISO 5351 1‰ g偏差在本技术规范的允许范围之内。 处理/未处理和老化/未老化的样片都要给出特性粘度的平均值，结果应该用毫升每克表示。
After accelerated ageing, the limiting viscosity number of the treated paper has to be higher than that of the untreated paper.
NOTE 2 When looking at different deacidification treatments, the ratios of the limiting viscosity numbers of treated versus untreated papers after ageing can be compared if identical test papers are used.
For the calculation of DP, a [η]-DP relation for cellulose dissolved in CED is given in the formula below. The limiting viscosity number is converted to degree of polymerisation by DP = 0,9√(1,65 × [η]) (see Reference ).
关于DP（聚合度）的计算,特性粘度的数字转化为聚合度的DP = 0,9√(65×(η))(见参考文献)。（内聚能密度(Cohesive Energy Density)）
NOTE 3 The degree of polymerisation describes the average chain length of a polymer, in case of paper that of the mixture of cellulose and hemicelluloses. As the stability of paper is directly related to the chain lengths of (hemi) cellulose (longer polymer chains usually give stronger papers) this parameter can be considered as very important for the entire integrity of paper. In addition, it is a sensitive measure of cellulose degradation and hence very useful to address changes upon aging before and after deacidification. The sample amount required for analysis ranges between 75 mg and 750 mg for a triple determination depending on the sample DP (samples of lower DP require higher sample amounts). DP analysis using CED is limited to samples with little or no lignin content. Excess alkaline reserve is removed prior to DP analysis with an HCl treatment step. This HCl treatment only removes alkaline reserve which can in some cases interfere with DP measurement. The treatment does not degrade cellulose.
NOTE 4 For the determination of DP, also other standards (Cadoxen, Cuoxam, see Reference ), and more sophisticated methods like size exclusion chromatography (SEC) coupled to light scattering do exist. They are either less frequently used/offered or in case of SEC more expensive. They also yield reliable cellulose DP data.
188.8.131.52 Folding endurance (optional) 纸张耐折度的测量（非必选）
The machine direction folding endurance of the test papers shall be determined as described in ISO 5626 before and after accelerated ageing. The test instrument should be set with an appropriate tension to ensure that measurements give meaningful results.
NOTE For example, a typical setting for the MIT instrument would be to use a mass of 500 g for tension.
Mean folding endurance and fold number are to be determined as defined by ISO 5626. After accelerated ageing, the fold number of the treated paper has to be higher than that of the untreated paper.
5.4 Routine monitoring 常规监测
5.4.1 Frequency of sampling and sample quantities 采样频率和样本数量
For routine monitoring, test papers from the same batch used in process validation should be used. For batch processes, a test set consists of four test sheets A5 or larger which are placed in bound original volumes thicker than 3 cm before deacidification as described in 5.3.2. For continuous processes, the test papers of one test set should be treated alternating with sheets of original items.
The frequency of routine monitoring is one test set per production day and apparatus for batch processes and one test set per every five production days and apparatus for continuous processes.
The sheets are distributed randomly, but their position should be documented adequately.
5.4.2 Test methods and minimum requirements 测试方法和最低要求
184.108.40.206 Alkaline reserve 碱性储备量
The quantity of alkaline reserve shall be determined as described in ISO 10716.
The minimum requirement for alkaline reserve is 0,5 mass % expressed as MgCO3. The greater of 0,5 mass % or 2/3 of the alkaline reserve obtained in process validation (220.127.116.11.) should be reached in routine monitoring.
18.104.22.168 pH measurement (optional) pH值检测 （非必选）
The aqueous extract pH value has to be determined according to ISO 6588‑1.
The pH value of the paper after deacidification has to be higher than 6,5. Additionally, it has to be at least as high as the pH value measured during the process validation (22.214.171.124) minus 0,5 pH units.
液态提取pH值要参考ISO 6588 - 1。脱酸后纸张的pH值要高于6,5。此外,该值不得低于工艺验证过程中的pH(126.96.36.199)的 0、5 pH
NOTE In addition to this measurement of aqueous extract pH, measurements of surface pH are sometimes performed. The surface pH is a faster method compared to extraction pH to judge the pH status of a paper. If applied correctly (see Reference ), surface pH measurements also allow on-site measurements in libraries and archives and can also be used to follow the stability of deacidification on a longer timescale. However, surface pH measurement has its limits. It works well for acidic to neutral papers and also gives reasonable data until about pH 9. Usually, surface pH measurement has been successfully used with immersion treatments. Surface pH measurement may fail when larger amounts of alkaline reserve deposits are present at the paper surface and the solubility limit is reached.
6 Report 报告
During both process validation and routine monitoring the data should be documented in a way which is understandable for the customer. The testing laboratory shall include the following in the written report:
a) the number and extent of the batch and/or order; / 每批/每个订单的数量和进展程度
b) the dates of treatment and period and final date of reconditioning; / 处理的日期和周期，及最后整理的日期
c) the date and place of testing; 测试的日期与地点
d) any other observation made directly related to the deacidified material (e.g. same batch or last examination before treatment of this respective customer) that may be of importance regarding deacidification treatment; /任何其他与脱酸材料有关的调查(如同一批或每个客户脱酸处理前最后的检测）对脱酸处理都是很重要的;
e) any deviations from this Technical Specification and any circumstances that may have affected the results; 任何与该技术规范不同和任何会影响处理结果的因素
f) for process validation: test results obtained when testing as specified in 188.8.131.52, 184.108.40.206, 220.127.116.11, 18.104.22.168 and 22.214.171.124 (optional), both on untreated test papers as well as on treated test papers.
关于工艺验证：处理及未处理的纸张都根据126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11 and 18.104.22.168 (optional)步骤进行的结果检测，
In addition: test results obtained when testing as specified in 22.214.171.124, 126.96.36.199, 188.8.131.52 and 184.108.40.206 (optional), both on untreated test papers as well as on treated test papers, all of which have been subjected to accelerated ageing (in accordance with 220.127.116.11). All data should be expressed as stated in this Technical Specification or in the relevant standard referred to.
For routine monitoring: Test results obtained when testing as specified in 18.104.22.168 and 22.214.171.124. (optional), both on untreated test papers and on treated test papers. The results obtained during process validation should be used as reference data. All data shall be expressed as stated in this Technical Specification or in the relevant standard referred to. If the results of the first determination fail the limits of the used standard, a second determination is needed and should be denoted.
常规监测: 对未经处理和处理过的测试纸 根据126.96.36.199 188.8.131.52(可选)做出监测结果。验证过程中获得的结果应作为参考数据。所有数据应以本技术规格书或其他提过的相关标准表述。如果第一次验证的结果没有达到使用标准,需要做第二次验证。
g) for process validation: A statement that the tested deacidification process meets or fails to meet the requirements of this Technical Specification. In the latter case, the specific reason shall be stated.
For routine monitoring: A statement that the tested routine job meets or fails the requirements of this Technical Specification. In the latter case, the specific reason should be stated.
NOTE A sample test record form is given in Annex B.Annex B中的样品测试记录
Annex A (informative / 信息)
Negative side effects and insufficient deacidification / 副作用和不充分的脱酸
Large scale deacidification processes may lead to negative side effects like bleeding of colours (of stamps, inks, etc.), white deposits of deacidification particles on the surface of papers and bindings or slight colour changes of treated papers. The occurrence of such negative side effects is strongly dependent on the type of process and the nature of the treated objects.
Although providers of large scale deacidification treatments try to reduce the negative side effects as much as possible, it is impossible to totally avoid them within a mass treatment of very different paper objects. The same holds true for the deacidification itself which may be insufficient in some cases.
For this reason, providers of deacidification processes should indicate any process-specific side effects known to them and, before placing an order, the customer should examine these using suitable samples and weigh up risks and opportunities for each individual job, depending on the objectives of the measures. The customer then has to decide whether he considers the possible risks to be reasonable and acceptable, taking due consideration of the cultural and historical significance and/or where appropriate, the artistic value of the items.
Whatever the case may be, in addition to the methods of testing, test papers and books described here, every customer is, of course, free to carry out his own tests on any paper of his choice, preferably on original items wherever this is possible.
It goes without saying that any process for deacidifying paper should ensure the unconditional preservation of the information contained on the paper.
Annex B (informative / 信息)
Sample forms for documentation 文档的表格示例
B.1 Sample forms for documentation — Process validation test record
Table B.1 — General data 通用数据
Table B.2 — pH value (cold extraction) (184.108.40.206)
Table B.3 — pH measurement:pH值测量
Mean value and relative standard deviation from four valid sample sets / 从四组有效样品中提取平均值及相对标准差
Table B.4 — Alkaline reserve (220.127.116.11) / 碱性储备量
Table B.5 — Alkaline reserve measurement: 碱性储备量测量
Mean value and relative standard deviation from four valid sample sets
Table B.6 — Uniformity of deacidification (18.104.22.168)
Table B.7 — Uniformity measurement:脱酸均匀性测量
Mean value, standard deviation and relative standard deviation from four valid sample sets