# US 8,540,848 B2 · Method and device for a de-acidifying paper

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- Number: US 8,540,848 B2
- Document ID: US8540848B2
- Status: Granted
- Kind: B2
- Application number: 12/678,364
- Filed: 2008-09-17
- Published: 2011-04-21
- Granted: 2013-09-24
- Earliest claimed: 2007-09-17
- Assignees: OmniAccess B.V.
- Applicants: Stephanus Gerardus Johannes Blankenborg; Maaike Jacobine Esther Van Roosmalen
- Inventors: Stephanus Gerardus Johannes Blankenborg; Maaike Jacobine Esther Van Roosmalen
- Web page: https://patentgrep.com/patent/US8540848B2

## CPC

- D21H 25/18: of old paper as in books, documents, e.g. restoring
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR

## Abstract

For decades books and other paper documents have been deteriorating in archives and libraries around the world because the acidity of the paper is increasing so much (wherein the pH decreases) that the paper cellulose is decomposing so that the paper loses its cohesion and thereby degenerates in terms of quality. The invention relates to an improved method for de-acidifying paper. The invention also relates to a device for applying such a method.

## Claims

### Claim 1

Method for de-acidifying paper, comprising the steps of:
A) bringing the paper to be treated into contact with liquid carbon dioxide or supercritical carbon dioxide, wherein the fluid liquid carbon dioxide or supercritical carbon dioxide is provided with at least one alkaline alkoxy compound comprising an aminoalkylalkoxysilane compound or a derivative thereof, whereby the paper is impregnated with the aminoalkylalkoxysilane compound or a derivative thereof, and
B) ending the treatment according to step A) by reducing the pressure, whereby the liquid carbon dioxide or supercritical carbon dioxide is passed into the gas phase and is removed from the paper.

### Claim 2 (depends on 1)

Method as claimed in claim 1, wherein step A) is performed at a temperature and pressure which are equal to or higher than the critical temperature and the critical pressure of carbon dioxide.

### Claim 3 (depends on 1)

Method as claimed in claim 1, wherein the aminoalkylalkoxysilane compound is formed by at least one of the following compounds: an aminoalkylmonoalkoxysilane compound, aminoalkyldialkoxysilane compound, aminoalkyltrialkoxysilane compound or a derivative thereof.

### Claim 4 (depends on 1)

Method as claimed in claim 1, wherein the aminoalkyl group of the aminoalkylalkoxysilane compound comprises at least ten carbon atoms.

### Claim 5 (depends on 1)

Method as claimed in claim 1, wherein the alkoxy group comprises one or two carbon atoms.

### Claim 6 (depends on 1)

Method as claimed in claim 1, wherein the aminoalkylalkoxysilane compound is formed by at least one of the following compounds: 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxy silane, 4-aminobutyl-triethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, (N,N-dimethyl-3-aminopropyl)-trimethoxysilane, (N,N-diethyl-3-aminopropyl)-trimethoxysilane, N-phenylaminopropyltrimethoxysilane, -(6-aminohexyl)-3-aminopropyltrimethoxysilane, bis[3-(trimethoxysilyl)propyl]amine or bis[3(triethoxysilyl)propyl]amine.

### Claim 7 (depends on 1)

Method as claimed in claim 1, wherein the concentration of the aminoalkylalkoxy compound in the carbon dioxide for performing step A) lies between 0.01 and 40 mol %.

### Claim 8 (depends on 1)

Method as claimed in claim 1, wherein the carbon dioxide is provided with at least one additive for performing step A).

### Claim 9 (depends on 8)

Method as claimed in claim 8, wherein the additive is formed by at least one of the following components: a bleaching agent, an antioxidant, a disinfectant or a substance for preventing ink corrosion.

### Claim 10 (depends on 1)

Method as claimed in claim 1, wherein step B) is realized by reducing the pressure to atmospheric pressure.

### Claim 11 (depends on 1)

Method as claimed in claim 1, wherein step B) is realized by reducing the temperature to room temperature.

### Claim 12 (depends on 1)

Method as claimed in claim 1, wherein step A) and step B) are repeated at least once after initially performing step A) and step B).