阅读说明：本技术 一种纸张脱酸用的混悬剂 (Suspension for deacidifying paper ) 是由 侯萌 寻广龙 于 2020-04-22 设计创作，主要内容包括：本发明属于纸张脱酸技术领域,具体涉及一种纸张脱酸用的混悬剂。所述纸张脱酸用的混悬剂含有如下重量百分比的组分：有效成分：0.5-5wt％；附加剂：2-20wt％；余量分散介质；所述有效成分选自金属氧化物、金属氢氧化物、金属碳酸盐、金属碳酸氢盐中的一种或多种。本发明制备的纸张脱酸用的混悬剂,稳定性好,再分散性能良好,产品保质期长达2年,且絮凝微粒小,避免了在纸张表面留下肉眼可见的白色残留物,能够显著提高酸化纸张的pH值,具有较好的脱酸效果；本发明制备的纸张脱酸用的混悬剂可以提高部分纸张的白度,对纸张的物理强度没有明显影响,对档案的不同字迹均未产生明显影响,同时,无刺激性,低毒,安全性好。(The invention belongs to the technical field of paper deacidification, and particularly relates to a suspension for paper deacidification. The suspension for deacidifying the paper comprises the following components in percentage by weight: the effective components are as follows: 0.5-5 wt%; addition agent: 2-20 wt%; the balance of a dispersion medium; the active ingredients are selected from one or more of metal oxide, metal hydroxide, metal carbonate and metal bicarbonate. The suspension for deacidification of paper prepared by the invention has good stability, good redispersion performance, long shelf life of the product up to 2 years, small flocculating particles, no macroscopic white residue left on the surface of the paper, and good deacidification effect, and can obviously improve the pH value of the acidified paper; the suspension for deacidifying the paper, which is prepared by the invention, can improve the whiteness of part of the paper, has no obvious influence on the physical strength of the paper, has no obvious influence on different writing of archives, and simultaneously has no irritation, low toxicity and good safety.)

1. A suspension for deacidifying paper is characterized by comprising the following components in percentage by weight:

the effective components are as follows: 0.5-5 wt%;

addition agent: 2-20 wt%;

the balance of a dispersion medium;

the active ingredients are selected from one or more of metal oxide, metal hydroxide, metal carbonate and metal bicarbonate.

2. The suspension for deacidifying paper according to claim 1, wherein said metal oxide comprises magnesium oxide.

3. Suspension for deacidification of paper according to claim 2, characterized in that said magnesium oxide is nano magnesium oxide; the particle size of the magnesium oxide is 10-50 nm.

4. Suspension for deacidification of paper according to claim 1, characterized in that said additional agent is selected from one or more of silane coupling agents, reinforcing agents, halogenated hydrocarbons.

5. Suspension for deacidification of paper according to claim 4, characterized in that said reinforcing agent is a water-soluble high molecular polymer.

6. The suspension for deacidifying paper according to claim 5, wherein the water-soluble high-molecular polymer is polyacrylamide and/or polyvinyl alcohol.

7. Suspension for deacidification of paper according to any of claims 1 to 6, characterized in that said dispersion medium is selected from one or more of nonylphenol polyoxyethylene ether, dodecylbenzene sulphonate, dodecyl sulphate, fluorocarbon dispersion medium.

8. The suspension for deacidification of paper according to claim 7, wherein the fluorocarbon dispersion medium is selected from one or more of anionic fluorocarbon surfactant, cationic fluorocarbon surfactant, zwitterionic fluorocarbon surfactant and non-ionic fluorocarbon surfactant.

9. The suspension for deacidifying paper according to claim 8, wherein the mass ratio of the metal oxide to the cationic fluorocarbon surfactant is 1: (28.3-44).

10. A process for preparing a suspension for deacidifying paper as defined in any one of claims 1-9, comprising the steps of:

slowly adding the additive into the dispersion medium, stirring uniformly, adding the metal oxide, and uniformly mixing by adopting ultrasonic, mechanical grinding and high-speed dispersion or using a homogenizer to obtain the suspension for deacidification of the paper.

Technical Field

The invention belongs to the technical field of paper deacidification, and particularly relates to a suspension for paper deacidification.

Background

Chemical pulp papermaking was emerging at the end of the 18 th century. Chemical pulp papermaking is a method of chemically treating papermaking raw materials at high temperature and high pressure to remove lignin and other impurities to make paper pulp, and then making paper. The cellulose content of the raw materials of wood, bamboo, straw and the like for papermaking is low, and the raw materials are acidic or easily generate acidic derivatives during oxidation and hydrolysis; although most of lignin and other impurities in the raw materials can be removed by chemical pulp papermaking, the treatment conditions are severe, and the damage to fibers is large; moreover, alum and rosin are mostly used for sizing treatment, and a large amount of acidic medium is introduced; in addition, chemicals, metal ions, etc. remaining in the pulping process are not good for the durability of the paper. Generally, chemical pulp paper has a life expectancy of 200 to 500 years, but acidification of the paper is accelerated by external acidic substances such as increasingly severe environmental pollution.

In the face of severe paper acidification problems, paper deacidification is a key method to extend paper life. Libraries, archives, museums and folks in China collect a large amount of precious paper documents such as books, ancient books, notes, archives, newspapers, drawings, deeds, bills, paper money, stamps and the like. The papers of these paper documents are commonly acidified and, if not deacidified, gradually deteriorate. However, as long as the paper is acidic, the damage is only a time problem, the service life of the paper is reached, and then it is not time to take protective measures.

The main component of paper is cellulose which is very stable in a neutral atmosphere, but cellulose is very easy to hydrolyze in an acid environment, and the paper becomes brittle, which is also necessary for deacidification treatment. However, it should also be noted that cellulose is susceptible to alkaline hydrolysis in a highly alkaline environment, resulting in a substantial reduction in paper strength. The above patent sometimes uses strong alkaline inorganic substance in the deacidification agent preparation, which easily causes the paper strength reduction after alkaline hydrolysis; some of these paper sheets, although using organic agents that have little effect on the shape of the paper sheet, tend to lose some of their binding components and also cause a reduction in the strength of the paper sheet. Therefore, the alkalinity of the deacidification agent should be controlled within a certain range, so that alkaline hydrolysis during deacidification is avoided, and the storage life is prolonged.

Disclosure of Invention

In order to solve the technical problems, the invention provides a suspension for deacidifying paper, which comprises the following components in percentage by weight:

the effective components are as follows: 0.5-5 wt%;

addition agent: 2-20 wt%;

the balance of a dispersion medium;

the active ingredients are selected from one or more of metal oxide, metal hydroxide, metal carbonate and metal bicarbonate.

As a preferred embodiment, the metal oxide comprises magnesium oxide.

As a preferred technical scheme, the magnesium oxide is nano magnesium oxide; the particle size of the magnesium oxide is 10-50 nm.

As a preferred technical scheme, the additive is selected from one or more of silane coupling agent, reinforcing agent and halogenated hydrocarbon.

In a preferred embodiment, the enhancer is a water-soluble high molecular polymer.

As a preferable technical solution, the water-soluble high molecular polymer is polyacrylamide and/or polyvinyl alcohol.

As a preferable technical scheme, the dispersion medium is selected from one or more of nonylphenol polyoxyethylene ether, dodecylbenzene sulfonate, dodecyl sulfate and fluorocarbon dispersion medium.

As a preferred technical solution, the fluorocarbon dispersion medium is selected from one or more of anionic fluorocarbon surfactant, cationic fluorocarbon surfactant, zwitterionic fluorocarbon surfactant, and nonionic fluorocarbon surfactant.

As a preferable technical scheme, the mass ratio of the metal oxide to the cationic fluorocarbon surfactant is 1: (28.3-44).

In a second aspect, the present invention provides a process for preparing a suspension for deacidification of paper, said process comprising the steps of:

slowly adding the additive into the dispersion medium, stirring uniformly, adding the metal oxide, and uniformly mixing by adopting ultrasonic, mechanical grinding and high-speed dispersion or using a homogenizer to obtain the suspension for deacidification of the paper.

Has the advantages that: the invention provides a suspension for deacidification of paper, which adopts magnesium oxide with the particle size of 20nm, novel amphoteric polyacrylamide and N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide as a formula, has good stability, good redispersion performance, long shelf life of a product of 2 years and small flocculating particles, avoids visible white residues on the surface of the paper, can obviously improve the pH value of the acidified paper and has better deacidification effect; the suspension for deacidifying the paper, which is prepared by the invention, can improve the whiteness of part of the paper, has no obvious influence on the physical strength of the paper and has no obvious influence on different writing of files. Meanwhile, the paint has no irritation, low toxicity and good safety.

Detailed Description

The technical features of the technical solutions provided by the present invention are further clearly and completely described below with reference to the specific embodiments, and the scope of protection is not limited thereto.

The words "preferred", "more preferred", and the like, in the present invention refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

"Polymer" means a polymeric compound prepared by polymerizing monomers of the same or different types. The generic term "polymer" embraces the terms "homopolymer", "copolymer", "terpolymer" and "interpolymer". "interpolymer" means a polymer prepared by polymerizing at least two different monomers. The generic term "interpolymer" includes the term "copolymer" (which is generally used to refer to polymers prepared from two different monomers) and the term "terpolymer" (which is generally used to refer to polymers prepared from three different monomers). It also includes polymers made by polymerizing four or more monomers. "blend" means a polymer formed by two or more polymers being mixed together by physical or chemical means.

In order to solve the technical problems, the invention provides a suspension for deacidifying paper, which comprises the following components in percentage by weight:

the effective components are as follows: 0.5-5 wt%;

addition agent: 2-20 wt%;

the balance of a dispersion medium;

the active ingredients are selected from one or more of metal oxide, metal hydroxide, metal carbonate and metal bicarbonate.

In a preferred embodiment, the suspension for deacidifying the paper contains the following components in percentage by weight:

the effective components are as follows: 2-3 wt%;

addition agent: 10-12 wt%;

the balance being a dispersing medium.

In a preferred embodiment, the suspension for deacidifying the paper contains the following components in percentage by weight:

the effective components are as follows: 2.5 wt%;

addition agent: 11 wt%;

the balance being a dispersing medium.

Active ingredient

In some embodiments, the active ingredient is selected from one or more of a metal oxide, a metal hydroxide, a metal carbonate, a metal bicarbonate.

The metal oxides include: magnesium oxide and calcium oxide.

The metal hydroxide includes: magnesium hydroxide, calcium hydroxide.

The metal carbonates include: magnesium carbonate, calcium carbonate.

The metal bicarbonate can be exemplified by: magnesium bicarbonate and calcium bicarbonate.

In a preferred embodiment, the active ingredient is a metal oxide.

In a preferred embodiment, the metal oxide comprises magnesium oxide.

In a preferred embodiment, the magnesium oxide is nano-magnesium oxide; the particle size of the magnesium oxide is 10-50 nm.

In a preferred embodiment, the particle size of the magnesium oxide is 20 nm.

In a preferred embodiment of the present invention, the active ingredient is magnesium oxide; the particle size of the magnesium oxide is 20 nm.

The inventor unexpectedly discovers in the research process that common metal oxides of magnesium oxide and calcium oxide are selected as alkaline deacidification substances, so that acidic substances in paper can be neutralized, other elements cannot be introduced, and possible side reaction risks are avoided. In addition, the inventor also unexpectedly finds that the magnesium oxide with the particle size of 10-50nm is beneficial to realizing long-term uniform dispersion of magnesium oxide alkaline particles in a dispersion system, and is also beneficial to ensuring that the magnesium oxide alkaline particles penetrate into the paper and are deposited on the surface of cellulose during the use process, thereby improving the effectiveness of deacidification and increasing the effective alkali retention. In the further research process, the inventor finds that when the particle size of the magnesium oxide is 20nm, the metal oxide is flocculated into particles in the suspension, the flocculated particles are small, white residues visible to the naked eye on the surface of paper are avoided, the uniformity of the flocculated particles of the metal oxide is good, and the suspension is stable, and the good deacidification effect can be achieved no matter the suspension is sprayed on the paper or the paper is placed into the suspension for soaking. Under the combined action of the magnesium oxide with the particle size of 20nm, a fluorocarbon solution dispersion medium and the novel amphoteric polyacrylamide, the pH value of paper can be improved by 3.5 after the suspension is used.

Additive agent

In some embodiments, the additive is selected from one or more of a silane coupling agent, a reinforcing agent, a halogenated hydrocarbon.

Examples of the silane coupling agent include gamma- (2, 3-glycidoxy) propyltrimethoxysilane, 3-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, 1, 2-bis (triethoxysilyl) ethane, and N- (β -aminoethyl) -gamma-aminopropyltrimethoxysilane.

Examples of such enhancers are: water-soluble high-molecular polymer, methyl potassium silicate, methyl sodium silicate, modified starch and modified cellulose.

The halogenated hydrocarbons may be exemplified by: carbon tetrachloride, perchloroethylene, trichlorotrifluoroethane, 1-fluoro-6-chlorohexane, perfluorohexane, perfluorooctane, perfluoroheptane.

In some preferred embodiments, the additive is a reinforcing agent.

In some preferred embodiments, the enhancer is a water-soluble high molecular polymer.

In some preferred embodiments, the water-soluble high molecular polymer is polyacrylamide and/or polyvinyl alcohol.

In a preferred embodiment, the water-soluble high molecular polymer is polyacrylamide.

In a preferred embodiment, the polyacrylamide is a novel amphoteric polyacrylamide.

In a preferred embodiment, the preparation method of the novel amphoteric polyacrylamide comprises the following steps:

(1) adding cyclohexane, n-butanol and compound emulsifier, starting electric stirrer, heating water bath, introducing nitrogen gas, and heating at 300r min^-1Stirring at speed for about 15 min;

(2) adjusting the pH value of the ternary monomer aqueous solution to 5, dripping for 20min, and adding an initiator when the temperature of a water bath is raised to 50 ℃; reacting for 3h, washing with acetone, and drying in a vacuum drying oven for 10h to obtain the novel amphoteric polyacrylamide;

the mass fraction of the ternary monomer aqueous solution is 20 wt%; the ternary monomer is acrylamide, methacryloyloxyethyl trimethyl ammonium chloride and 2-acrylamide-2-methyl-1-propane sulfonic acid; the mol ratio of the acrylamide to the methacryloyloxyethyl trimethyl ammonium chloride to the 2-acrylamido-2-methyl-1-propanesulfonic acid is 1: 1: 1;

the compound emulsifier is Span80 and Tween 80; the mass ratio of the Span80 to the Tween80 is 1: 1;

the mass ratio of the cyclohexane to the n-butanol to the compound emulsifier to the ternary monomer aqueous solution to the initiator is 20: 30: 15: 65: 2.

according to the preferred technical scheme, the additive is novel amphoteric polyacrylamide.

The metal oxide particles are easy to agglomerate and settle, so that the stability of the metal oxide in a system is poor, the size and the distribution of particles in the suspension are important indexes for evaluating the quality of the suspension, and the deacidification effect of the suspension is influenced. The inventor unexpectedly finds that the stability of the metal oxide in the system can be improved by adding the novel amphoteric polyacrylamide in the research process, and the reason guessed by the inventor is probably that the polyacrylamide forms hydrogen bond action with hydroxyl on the surface of the plant fiber through amide groups on a molecular chain, so that the bonding between fibers is increased, the strength performance of the paper is improved, and the agglomeration and sedimentation of metal oxide particles into large particles are effectively avoided.

Dispersion medium

In some embodiments, the dispersion medium is selected from one or more of nonylphenol polyoxyethylene ether, dodecylbenzene sulfonate, dodecyl sulfate, fluorocarbon dispersion medium.

The polyoxyethylene nonyl phenyl ether may be exemplified by: nonylphenol polyoxyethylene (7) ether, nonylphenol polyoxyethylene (9) ether, nonylphenol polyoxyethylene (10) ether or nonylphenol polyoxyethylene (15) ether.

The dodecylbenzene sulfonate may be exemplified by: sodium dodecylbenzene sulfonate and potassium dodecylbenzene sulfonate.

The lauryl sulfates can be exemplified by: sodium dodecyl sulfate, potassium dodecyl sulfate.

As the fluorocarbon dispersion medium, there can be exemplified: fluorocarbon carboxylate, fluorocarbon sulfate, fluorocarbon sulfonate, fluorocarbon phosphate, fluorocarbon quaternary ammonium salt, fluorocarbon carboxybetaine, fluorocarbon sulfobetaine, fluorocarbon amino acid salt.

In some preferred embodiments, the dispersion medium is a fluorocarbon dispersion medium.

In some preferred embodiments, the fluorocarbon dispersion medium is selected from one or more of an anionic fluorocarbon surfactant, a cationic fluorocarbon surfactant, a zwitterionic fluorocarbon surfactant, a non-ionic fluorocarbon surfactant.

In some preferred embodiments, the fluorocarbon dispersion medium is a cationic fluorocarbon surfactant.

In a preferred embodiment, the cationic fluorocarbon surfactant is N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide.

In a preferred embodiment, the process for preparing N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide comprises the steps of:

(1) synthesizing N-methyl-N-perfluorohexylethylethanolamine, namely adding 4g of N-methylethanolamine, dissolving with 20m L g of DMF, adding 3.5g of anhydrous potassium carbonate and 0.2g of potassium iodide, stirring at room temperature for 20min, heating to reflux, adding 4.27g of perfluorohexylbromoethane, reacting and refluxing for 24h, carrying out reduced pressure distillation to remove the solvent, dissolving the solid with DMF, filtering to remove inorganic salts, carrying out reduced pressure distillation to remove DMF, carrying out vacuum drying, and carrying out separation and purification to obtain N-methyl-N-perfluorohexylethylethanolamine;

(2) weighing 4.25g of N-methyl-N-perfluorohexylethylethanolamine, adding 30m of L acetone, fully stirring for dissolving, dropwise adding 2.15g of methyl iodide, heating until the solution flows back, reacting for 12 hours, filtering the precipitate, and recrystallizing to obtain the N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide.

In a preferred embodiment of the present invention, the dispersion medium is N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide.

The inventor unexpectedly finds that the fluorocarbon dispersion medium is non-toxic and non-corrosive and has small irritation to skin, the cationic fluorocarbon surfactant has low surface tension and high vapor pressure, so that the suspension prepared by the invention has excellent wettability and volatility, the efficiency of the suspension for deacidifying paper is high, and the paper can be quickly dried within 10-20 seconds. The reason the inventor guesses may be that the cationic fluorocarbon surfactant has nonpolar hydrocarbon chain with hydrogen atoms replaced by fluorine atoms completely or partially to form hydrophobic and oleophobic fluorocarbon chain segment, is non-aqueous solution, has high chemical activity, high thermal stability, high chemical stability, hydrophobic and oleophobic properties, has very low surface tension, and the suspension can flow between paper fibers rapidly, and the flocculated metal oxide particles reach between paper fibers rapidly. In addition, the inventor unexpectedly discovers that when N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide is used as a dispersion medium, fluorocarbon nonpolar chains are directly or indirectly connected with ammonium salt groups, molecules of the fluorocarbon nonpolar chains have mutual repulsion, fluorine atoms have unique properties such as geometric size, electronegativity and the like, can be combined with fibers to improve the strength of paper, and meanwhile, the suspension agent has extremely low acting force on paper fibers, writing materials and binding materials, so that the paper deacidification operation does not damage the paper phase, the writing materials and the binding materials. The N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide can also solve the problem of difficult degradation of perfluorooctanoic acid compounds, is environment-friendly, has no irritation to skin and is more non-corrosive.

In a preferred embodiment, the mass ratio of the metal oxide to the cationic fluorocarbon surfactant is 1: (28.3-44).

In a preferred embodiment, the mass ratio of the metal oxide to the cationic fluorocarbon surfactant is 1: 34.6.

in a preferred embodiment, the mass ratio of the novel amphoteric polyacrylamide, N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide and magnesium oxide is (3-5): (28.3-44): 1.

in a preferred embodiment, the mass ratio of the novel amphoteric polyacrylamide, N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide and magnesium oxide is 4.4: 34.6: 1.

further, the inventors found that when the mass ratio of the novel amphoteric polyacrylamide, N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide, and magnesium oxide was 4.4: 34.6: 1, the redispersibility and the deacidification effect of the suspension can be simultaneously optimized, and the reason guessed by the inventor is probably that under the combined action of N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide and novel amphoteric polyacrylamide, the particle size of suspension flocculating fine particles D90 powder is just 300nm, the flocculating fine particles can penetrate into paper fibers, the deacidification effect is better achieved, the uniformity of the metal oxide flocculating fine particles is good, the suspension is stable, the suspension is shaken after being stored, sediments can be quickly redispersed, and the shelf life of the product is as long as 2 years. The suspension is stable, and the dosage accuracy of the effective components is ensured when the suspension is used in divided dosage.

The invention adopts magnesium oxide with the particle size of 20nm as an effective component, simultaneously inhibits the hydrolysis of β -glycosidic bond in cellulose under the action of novel amphoteric polyacrylamide and N-perfluorohexylethyl-N, N-dimethyl- (2-hydroxyethyl) ammonium iodide, ensures that the cellulose molecular chain of paper is not easy to break, does not obviously reduce the whiteness, the fighting strength and the folding endurance of the paper, even partially improves the whiteness, the fighting strength and the folding endurance of the paper, and the magnesium oxide with the particle size of 20nm gradually reacts with acid substances in the paper to realize acid-base neutralization to achieve the deacidification effect.

In a second aspect, the present invention provides a process for preparing a suspension for deacidification of paper, said process comprising the steps of:

slowly adding the additive into the dispersion medium, stirring uniformly, adding the metal oxide, and uniformly mixing by adopting ultrasonic, mechanical grinding and high-speed dispersion or using a homogenizer to obtain the suspension for deacidification of the paper.

The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.

In addition, the starting materials used are all commercially available, unless otherwise specified.