阅读说明：本技术 一种延缓纸张老化变黄及纸张上染料、颜料老化变色的方法 (Method for delaying aging and yellowing of paper and aging and discoloration of dye and pigment on paper ) 是由 李玉虎 祁赟鹏 周亚军 赵光涛 贾智慧 汪泳 于 2020-06-09 设计创作，主要内容包括：本发明公开了一种延缓纸张老化变黄及纸张上染料、颜料老化变色的方法,该方法将档案、图书、古旧字画等待处理样品直接整体放入密闭箱体,先抽真空后充入惰性气体进行预处理,然后抽真空至压力低于10mmHg,再充入惰性气体与环氧乙烷的混合气至常压,进行气体处理,即可延缓档案、图书、古旧字画等在长久保存中纸张变黄以及防止档案字迹、彩印油墨、字画颜料老化变色和褪色。本发明方法操作简单,通过加速老化试验可知,处理后能有效延缓纸张发黄变黑、防止各类档案字迹、印刷油墨、字画颜料老化褪色,档案、图书及古旧字画未发生变形,保持原貌,对纸张机械强度无影响。(The invention discloses a method for delaying paper aging yellowing and aging discoloration of dyes and pigments on paper, which comprises the steps of directly and integrally placing samples to be processed of archives, books and ancient scripts and paintings into a closed box, vacuumizing, then filling inert gas for pretreatment, vacuumizing until the pressure is lower than 10mmHg, filling mixed gas of inert gas and ethylene oxide to normal pressure, and performing gas treatment, so that the paper yellowing of the archives, the books, the ancient scripts and paintings in long-term storage can be delayed, and the archives, the color printing ink and the calligraphy and painting pigments are prevented from aging discoloration and fading. The method is simple to operate, and through an accelerated aging test, the yellowing and blackening of the paper can be effectively delayed after the treatment, the aging and the fading of various archives, printing ink and calligraphy and painting pigments can be prevented, the archives, the books and the ancient calligraphy and painting do not deform, the original appearance is kept, and the mechanical strength of the paper is not influenced.)

1. A method for delaying aging and yellowing of paper and aging and discoloration of dyes and pigments on the paper is characterized by comprising the following steps: putting the whole sample to be processed into a closed box body, vacuumizing, then filling inert gas for pretreatment, vacuumizing until the pressure is lower than 10mmHg, filling mixed gas of the inert gas and ethylene oxide to normal pressure, and carrying out gas treatment.

2. The method for retarding the yellowing caused by aging of paper and the discoloration caused by aging of dyes and pigments on paper as claimed in claim 1, wherein: the pretreatment temperature is 20-60 ℃, the relative humidity is 30-80%, and the pretreatment time is 2-48 h.

3. The method for retarding the yellowing caused by aging of paper and the discoloration caused by aging of dyes and pigments on paper as claimed in claim 2, wherein: the pretreatment temperature is 30-45 ℃, the relative humidity is 60% -80%, and the pretreatment time is 36-48 h.

4. The method for retarding the yellowing caused by aging of paper and the discoloration caused by aging of dyes and pigments on paper as claimed in claim 2, wherein: the pretreatment temperature is 40 ℃, the relative humidity is 80%, and the pretreatment time is 48 h.

5. The method for retarding the yellowing caused by aging of paper and the discoloration caused by aging of dyes and pigments on paper as claimed in claim 1, wherein: the volume ratio of the inert gas to the ethylene oxide in the mixed gas is 1: 9-9: 1, the filling rate of the mixed gas is 1-20 mmHg/min, and the gas treatment time is 2-24 hours.

6. The method for retarding the yellowing caused by aging of paper and the discoloration caused by aging of dyes and pigments on paper as claimed in claim 5, wherein: the volume ratio of the inert gas to the ethylene oxide in the mixed gas is 2: 8-4: 6, the filling rate of the mixed gas is 1-5 mmHg/min, and the gas treatment time is 8-12 hours.

7. The method for retarding the yellowing caused by aging of paper and the discoloration caused by aging of dyes and pigments on paper as claimed in claim 5, wherein: the volume ratio of the inert gas to the ethylene oxide in the mixed gas is 3:7, the filling rate of the mixed gas is 2mmHg/min, and the gas treatment time is 10 hours.

8. The method for retarding the aging yellowing of paper and the aging discoloration of dyes and pigments on paper according to any one of claims 1 to 7, wherein: the inert gas is argon or nitrogen.

9. The method for retarding the aging yellowing of paper and the aging discoloration of dyes and pigments on paper according to any one of claims 1 to 7, wherein: and after the gas treatment is finished, pumping out the gas in the box body, fully contacting the gas with water, fully degrading the gas through ultraviolet light, discharging the gas, filling nitrogen into the box body after the pressure in the box body is lower than 100mmHg, repeating the process twice, and opening the box to take out the sample.

Technical Field

The invention belongs to the technical field of protection of archives and cultural relics, and particularly relates to a method for delaying aging and yellowing of paper and aging and discoloration of dyes and pigments on the paper.

Background

Yellowing of paper is generally considered one of the early signs of aging and deterioration. According to the nature and storage condition of the paper, when the paper ages to a later stage, the yellow color may turn brown, and the paper may become brittle, which seriously affects the acquisition of the information recorded in the books and archives and the artistic value of the ancient calligraphy and painting. However, the change of the paper color along with time is rarely researched internationally and domestically, and the research on the prevention of the paper color change is not reported in documents. In addition, in the long-term storage process of archives, books and ancient calligraphy and painting, the discoloration and fading of the prints of the archives, the books and the ancient calligraphy and painting are also a problem which cannot be ignored. The discoloration or fading of the print can cause the deviation of the information expressed by the files and books or difficult reading, and the artistic value of the old painting and calligraphy is affected. However, researchers have few researches on color information protection of paper archives, books and cultural relics, and the researches on the color information protection through scale processing are not reported. Regarding the yellowing factor of paper during long-term storage, there are researchers who believe it is the reason for the lignin that is not removed during the paper-making process. The structure of the plant fiber is that cellulose is used as a skeleton, hemicellulose is connected to the surface of cellulose microfibril through a hydrogen bond, and lignin is filled in a gap formed by the cellulose and the hemicellulose through a covalent bond. Therefore, lignin is produced along with cellulose and hemicellulose, and the lignin is removed in the pulping and papermaking process, but cannot be completely removed.

The chemical property of lignin is very unstable, and the chemical change of lignin can be caused by temperature, humidity, acidity or chemical reagents. The phenolic hydroxyl, aliphatic hydroxyl and carboxyl content also affect the degradation properties of the lignocellulose. Li Muyang, Foster Cliff and other researches prove that the phenolic hydroxyl content and the degradation performance of the lignocellulose are in positive correlation. The wood is used as a main papermaking raw material, and the paper color change principle can be analyzed from the wood color change mechanism. Shenying et al extract teak aged by xenon lamp with benzene-ethanol mixed solvent for characterization analysis such as color change, infrared spectrum, ultraviolet absorption spectrum, gas chromatography-mass spectrometry, etc., find that quinones, aldehydes, etc. appear after wood aging, supposedly that the quinones, aldehydes, etc. appear as degradation products of lignin, namely, phenylpropanoid substances are formed through oxidation and esterification, and the result shows that the lignin degradation by illumination is the main cause of wood discoloration. Li Juan et al consider flavonoids, lignin and phenols as the main chemical components causing the color development and color change of wood.

Further, it is considered that an important factor for the aging and yellowing of paper is that the added aqueous solution of alum prevents the clouding and diffusion of the writing material, and prevents the clouding and diffusion of the writing material. The collosol is used in the mounting of painting and calligraphy in Tang Dynasty and its main components are gelatin and alum KAl (SO)₄)₂·12H₂O]The mixed aqueous solution of (1). The color fixing agent is mainly used for fixing colors in mounting of painting and calligraphy, and prevents painting and calligraphy pigment from being tinged or falling off in the mounting process. The authors also conducted related studies on the mechanism of the collosol in paper aging, and speculated that the presence of the collosol catalyzes the color development of lignin in paper.

In addition to yellowing and discoloration of paper, ink handwriting, printing ink, pigment and the like used in archives, books and ancient calligraphy and painting can also be discolored or faded due to the influence of temperature, illumination and the like in the long-term storage process. The pure blue ink and the red ink which are commonly used for files are easy to fade. The blue-black ink is relatively stable, and the pigment components of the blue-black ink are mainly acid ink blue and direct lake blue dye, so that the blue-black ink is easy to turn brown due to the increase of pH. The printing ink is also aged and faded by ultraviolet irradiation, the fading amplitude of the yellow ink is maximum, and the magenta ink has the slightest change of cyan and black.

Most of mineral pigments used in ancient and old calligraphy and painting are relatively stable, but realgar, white lead and the like are easy to discolor. The common disease of 'lead return' in calligraphy and painting is caused by the contact of white lead and the sulfurated gas in the air to generate black lead sulfide. Vegetable dyes fade more readily than mineral pigments.

The fading or discoloration of the pigment not only affects the readability and accuracy of the information recorded in the archives, but also leads to the artistic value of the ancient calligraphy and painting and color-printed books. Therefore, the prevention of the aging discoloration or fading of the file writing, printing ink, and painting pigment is an important research topic in the protection of files and cultural relics. The existing file and cultural relic protection technology has few researches, and no practical, effective and large-scale processing method exists.

Disclosure of Invention

The invention provides a method for delaying the aging and yellowing of paper and the aging and discoloration of dyes and pigments on the paper by only simple operations such as vacuumizing, inflating and the like in a closed container through researching the influence factors, discoloration mechanism and internal factors of the yellowing and blackening of the paper and the discoloration and fading of a writing and printing color material, and the method can obviously inhibit the yellowing and yellowing of the paper, prevent the discoloration of the pigments, prolong the service life of the paper and protect the value of books, files and cultural relics.

The technical scheme for solving the technical problems is as follows: putting the whole sample to be processed into a closed box body, vacuumizing, then filling inert gas for pretreatment, vacuumizing until the pressure is lower than 10mmHg, filling mixed gas of the inert gas and ethylene oxide to normal pressure, and carrying out gas treatment.

The pretreatment temperature is 20-60 ℃, the relative humidity is 30-80%, and the pretreatment time is 2-48 h; preferably, the pretreatment temperature is 30-45 ℃, the relative humidity is 60-80%, and the pretreatment time is 36-48 h; further preferably, the temperature of the pretreatment is 40 ℃, the relative humidity is 80%, and the pretreatment time is 48 hours.

The volume ratio of the inert gas to the ethylene oxide in the mixed gas is 1: 9-9: 1, the filling rate of the mixed gas is 1-20 mmHg/min, and the gas treatment time is 2-24 hours; preferably, the volume ratio of the inert gas to the ethylene oxide in the mixed gas is 2: 8-4: 6, the filling rate of the mixed gas is 1-5 mmHg/min, the gas treatment time is 8-12 h, further preferably, the volume ratio of the inert gas to the ethylene oxide in the mixed gas is 3:7, the filling rate of the mixed gas is 2mmHg/min, and the gas treatment time is 10 h.

The inert gas is preferably argon or nitrogen.

In the method, after the gas treatment is finished, the gas in the box body is pumped out and is fully contacted with water, then the gas is discharged after being fully degraded by ultraviolet light, nitrogen is filled in the box body after the pressure in the box body is lower than 100mmHg, the box is opened after the process is repeated twice, and the sample is taken out.

The invention has the following beneficial effects:

1. the invention firstly proposes that the gas-phase and large-scale treatment is carried out on paper archives, books, ancient and old calligraphy and painting, the color reaction of the paper color-developing group in the long-term storage process is delayed, the original appearance of the books is not required to be damaged by opening an archives roll box, the calligraphy and painting scroll is not required to be unfolded, the paper archives, the books and the ancient and old calligraphy and painting can be integrally and massively treated by directly placing the paper archives, the books and the ancient and painting into a box body, the large-scale degree is high, the interference on the archives, the books and the ancient and old calligraphy and painting is very small, and the.

2. The invention firstly proposes to carry out gas-phase and large-scale treatment on books, files, ancient calligraphy and painting and the like, prevents the ageing and discoloration or fading of files, printing ink and calligraphy and painting pigments in the long-term storage process, and effectively protects the colors and values of the books, the files and the ancient calligraphy and painting.

3. The invention uses argon and ethylene oxide to distribute gas, is safe and effective, has strong permeability, and can sterilize files, books and ancient and old calligraphy and painting while processing.

4. The tail gas is degraded by adopting water solubility and ultraviolet irradiation, can be completely degraded into water and carbon dioxide, does not contain any toxic and harmful gas, and realizes green and environment-friendly emission.

5. The method is simple to operate, and through an accelerated aging test, the yellowing and blackening of the paper can be effectively delayed and the original appearance can be kept after the paper is treated, and the treated files, books and calligraphy and painting do not deform and have no influence on the mechanical strength of the books, files and calligraphy and painting.

Drawings

FIG. 1 is a visual depiction of the color of an untreated pattern and a pattern treated using the method of example 2 (EO-Ar treatment) as a function of aging time.

FIG. 2 is a graph of the visible light reflectance of an untreated pattern (a) and a pattern (b) treated using the method of example 2 as a function of aging time.

FIG. 3 is a graph showing the change in color difference with age between an untreated pattern and a pattern treated by the method of example 2 (EO-Ar treatment).

FIG. 4 shows the yellowness index of an untreated sample and a sample treated by the method of example 2 (EO-Ar treatment).

FIG. 5 is a graph showing the comparison of the aging effects of the untreated calligraphy and painting simulation samples and the samples treated by the method of example 2 (a: the samples treated by the method of example 2, b: the untreated samples, c: the samples treated by the method of example 2 are subjected to the heat-humidity aging for 72 hours, and d: the untreated samples are subjected to the heat-humidity aging for 72 hours).

FIG. 6 is a graph comparing the effect of accelerated aging on an untreated book sample (top half) and its treatment by the method of example 2 (bottom half).

FIG. 7 is the color difference before and after UV aging of untreated and treated samples of a common pigment using the method of example 2.

FIG. 8 is the color difference before and after UV aging of untreated and ink samples treated using the method of example 2.

Fig. 9 is a graph comparing the effect of accelerated aging on an untreated color-printed book sample (top half) and its treated version using the method of example 2 (bottom half).

Detailed Description

The invention will be further described in detail with reference to the following figures and examples, but the scope of the invention is not limited to these examples.