LU500300B1

LU500300B1 - Hydrolysis-resistant alkenyl succinic anhydride sizing agent and preparation method and application thereof

Info

Publication number: LU500300B1
Application number: LU500300A
Authority: LU
Inventors: Dehai Yu
Original assignee: Univ Qilu Technology
Priority date: 2021-01-12
Filing date: 2021-06-18
Publication date: 2021-12-22
Also published as: CN112813729B; CN112813729A

Abstract

The present invention provides a preparation method of a hydrolysis-resistant alkenyl succinic anhydride (ASA) sizing agent, including: mixing a CNC aqueous dispersion with acetone, ammonia monohydrate and cetyltrimethylsiloxane, and performing ultrasonic dispersion to obtain a mixed solution I; adding perfluorooctyltriethoxysilane into the mixed solution I, and performing ultrasonic dispersion to obtain a mixed solution II; drying the mixed solution II to obtain CNC-R powder; mixing the CNC-R powder with perfluorohexane, performing ultrasonic dispersion, adding alkenyl succinic anhydride for mixing, and performing ultrasonic emulsification to obtain an ASA-A emulsion; and mixing the ASA-A emulsion with a sodium dodecyl sulfonate aqueous solution, and performing ultrasonic emulsification to obtain the hydrolysis-resistant alkenyl succinic anhydride sizing agent. The surface sizing performance of the ASA emulsion prepared by the method of the present invention is obviously improved, and at the same time, the hydrolysis-resistant performance of the ASA can be greatly improved.

Description

' LU500300

DESCRIPTION HYDROLYSIS-RESISTANT ALKENYL SUCCINIC ANHYDRIDE SIZING AGENT AND PREPARATION METHOD AND APPLICATION THEREOF TECHNICAL FIELD

[0001] The present invention relates to the technical field of papermaking, in particular to a hydrolysis-resistant alkenyl succinic anhydride sizing agent and a preparation method and application thereof.

BACKGROUND

[0002] An emulsion is a dispersion system formed by dispersing one liquid in another liquid immiscible with the liquid, mostly formed by mixing a water-insoluble oil phase with a water phase, and is widely applied to industries of papermaking, food, cosmetics, medicines and the like. The emulsion is a thermodynamically unstable system. In order to maintain relative stability (kinetic stability) of the emulsion, an emulsifier or stabilizer must be added in a preparation process of the emulsion. The traditional emulsifier or stabilizer is mostly a surfactant and a high-molecular polymer with surface activity, and the stability of the emulsion is maintained by reducing the interface tension between oil-phase liquid and water-phase liquid, providing a stable interface film and improving the viscosity of a continuous phase. In recent years, solid particles have attracted more and more attention because they can avoid the adverse influence of the surfactant on the environment, stabilize a high-concentration disperse phase emulsion, and the emulsions are less influenced by the changes of a pH value, a salt concentration, a temperature and an oil phase composition. For example, in the papermaking industry, in order to be compatible with a papermaking system using water as a medium, a water-insoluble papermaking sizing agent needs to be emulsified into an O/W type emulsion, the papermaking sizing purpose is to increase the water resistance of paper, the presence of the surfactant may cause adverse influence on the environment and may also generally reduce the water resistance of the paper, but these adverse influences of the surfactant can be avoided by stabilizing the sizing agent emulsion by using solid particles.

[0003] The papermaking industry in the 20 century changed from an acidic papermaking system to a neutral-alkaline papermaking system, and it was a revolutionary change of a papermaking process, greatly improved the paper quality, expanded a filler range, reduced pulp consumption and energy consumption, reduced environmental pollution, and prolonged the service life of equipment. Since 1989, China began to use neutral and alkaline sizing in production, and the neutral and alkaline sizing has been gradually popularized in recent years, and alkyl ketene dimer (AKD)/alkenyl succinic anhydride (ASA) are main sizing agents used at present. Large and medium-sized paper factories gradually use ASA. Particularly, in recent years, the ASA sizing agent has high reaction activity, low size cost and high curing speed, is thus widely used for internal sizing of fine paper and paperboards, and is particularly applicable to sizing of large-scale high-speed paper machines for in-machine coating. However, the ASA is a neutral papermaking sizing agent with high reactivity and has high hydrolysis speed, the sizing effect is reduced after the ASA emulsion is stored at a room temperature for more than 1 hour, hydrolysates may cause papermaking obstacles and reduce the sizing efficiency, so the ASA is required to be fast emulsified when being used, and the emulsified emulsion should be used as soon as possible. The alkenyl succinic anhydride (ASA) is only very easy to take hydrolysis, but also very easy to take alcoholysis and ammonolysis, so alcohol, carboxylic acid and ammonia compounds are not suitable to be used as emulsifiers for the ASA. At present, according to the emulsification of the ASA sizing agent, cationic starch and low molecular surfactants are mainly used for in situ emulsification, and are used immediately. However, the emulsified ASA emulsion has a very short quality guarantee period, and most sizing activity will be lost after 2 to 6 hours. Additionally, the starch used for ASA emulsification needs to be gelatinized and cooled before use, so that the ASA emulsification process is very complicated and difficult to control, and the problems of deposition, blanket blockage and the like are often caused. Additionally, the used surfactants also bring certain adverse influence on sizing, and cause some pollution to the environment.

[0004] At present, the research and achievements in an aspect of emulsification preparation of the ASA sizing agent have been also gradually enriched. The U.S. patent US6346554 discloses a method for stabilizing an ASA emulsion by using natural plant gum, and discloses that the sizing efficiency of the ASA can be improved by using the plant gum through increasing the retention of the ASA on the fiber, reducing the hydrolysis of the ASA and thus

> LU500300 caused deposition problems and forming a more uniform film on a fiber surface. The U.S. patent US5962555 discloses a method for emulsifying ASA by using a mixture of an ionene polymer and polyethyleneimine, wherein the ionene polymer can improve the sizing efficiency, and also has a bactericidal effect. Although these inventions avoid the inconvenience of starch gelatinization in operation, in order to obtain a stable ASA emulsion, about 2% of a surfactant still needs to be added. The U.S. patent US6284099 discloses a method for stabilizing an ASA emulsion by using papermaking anionic microparticle retention aids such as bentonite, colloidal silicon dioxide and organic microparticles, and a small number of surfactants and chelating agents, the microparticle retention aids and the sizing agent can be integrated, the operation is simplified, and the consumption of the surfactants is reduced. However, adverse influence caused by the surfactants cannot be completely avoided, the addition amount of microparticle components is too great, the concentration of the prepared ASA emulsion is very low, the conditions are unfavorable for the storage of the emulsion, and the hydrolysis of the ASA is serious. The Chinese patent

201510417679.9 discloses a biodegradable solid particle emulsifier based on modified cellulose nanocrystalline particles and an ASA sizing agent emulsified by the biodegradable solid particle emulsifier, the emulsified emulsion has good stability and can meet general production requirements, but the emulsion has the average stability, can only maintain the sizing activity for about 3 hours, and still cannot break through the limitation of the ASA used in on-site emulsification.

[0005] Based on the above, at present, the ASA sizing agent emulsion needs to be prepared and then immediately used, the ASA is poor in stability and easy to hydrolyze, and the quality guarantee period of a papermaking sizing agent emulsion is short.

SUMMARY

[0006] In order to overcome the defects in the prior art, the present invention provides a hydrolysis-resistant alkenyl succinic anhydride (ASA) sizing agent and a preparation method and application thereof. The prepared ASA sizing agent has high stability and strong hydrolysis resistance.

[0007] In order to achieve the above objective, the present invention adopts the following

* LU500300 technical solution:

[0008] A preparation method of a hydrolysis-resistant alkenyl succinic anhydride sizing agent includes the following steps: (1) mixing a cellulose nanocrystalline (CNC) aqueous dispersion with acetone, ammonia monohydrate and cetyltrimethylsiloxane, and performing ultrasonic dispersion to obtain a mixed solution I; adding perfluorooctyltriethoxysilane into the mixed solution I, and performing ultrasonic dispersion to obtain a mixed solution II; and drying the mixed solution II to obtain CNC-R powder; (2) mixing the CNC-R powder with perfluorohexane, performing ultrasonic dispersion, adding alkenyl succinic anhydride (ASA) for mixing, and performing ultrasonic emulsification to obtain an ASA-A emulsion; and (3) mixing the ASA-A emulsion with a sodium dodecyl sulfonate aqueous solution, and performing ultrasonic emulsification to obtain an ASA-B emulsion, 1e, the hydrolysis-resistant alkenyl succinic anhydride sizing agent.

[0009] A diameter of the cellulose nanocrystalline (CNC) is in a range of 3 to 10 nm, and a length is in a range of 100 to 500 nm.

[0010] In the mixed solution I, a mass percentage of the cellulose nanocrystalline is in a range of 0.05 to 2%, a mass percentage of the acetone is in a range of 0.1 to 1%, and a mass percentage of the ammonia monohydrate is in a range of 0.5 to 2%.

[0011] A consumption of the cetyltrimethylsiloxane is 2 to 30 % of the mass of the cellulose nanocrystalline.

[0012] A consumption of the perfluorooctyltriethoxysilane is 5 to 20% of the mass of the cellulose nanocrystalline.

[0013] The alkenyl succinic anhydride is at least one of dodecyl to octadecyl alkenyl succinic anhydride monomers, and more preferably one of tetradecyl to cetyl alkenyl succinic anhydride monomers. When the alkenyl succinic anhydride is a mixture, the present invention does not have specific definition on a proportioning ratio of the dodecyl to octadecyl alkenyl succinic anhydride monomers, and the mixing may be performed according to any proportioning ratio. The present invention uses the alkenyl succinic anhydride as a basic raw

> LU500300 material of the sizing agent.

[0014] A mass ratio of the CNC-R powder to perfluorooctane is 1:20-100.

[0015] A mass ratio of the alkenyl succinic anhydride to the perfluorooctane is 1:0.1-2.

[0016] A mass ratio of the ASA-A emulsion to the sodium dodecyl sulfonate aqueous solution is 1:0.5-10.

[0017] A mass percentage of the sodium dodecyl sulfonate aqueous solution is in a range of

0.1 to 2%, and preferably 0.2 to 1%.

[0018] The ultrasonic dispersion power is in a range of 500 to 3000 W.

[0019] A hydrolysis-resistant alkenyl succinic anhydride sizing agent obtained by adopting the preparation method is provided.

[0020] Application of the hydrolysis-resistant alkenyl succinic anhydride sizing agent to preparation of water-resistant paper is provided.

[0021] The present invention has the following advantages: The present invention realizes ultra-high stability and strong hydrolysis resistance of a W/O/O type composite ASA emulsion emulsified and stabilized by CNC-R and sodium dodecyl sulfonate. The ASA sizing agent emulsion prepared by the present invention cannot generate particle aggregation or precipitation and have no phase separated out and no emulsion breaking phenomenon after placement for 90 days, and the emulsion has good stability. Meanwhile, a sizing value of sized paper is almost not decreased, the sizing value when the internal sizing consumption of paper is 0.2% (a mass percentage relative to absolute dry pulp) can reach 455 s, and the sizing performance and the hydrolysis-resistant performance are good. The present invention is hopeful to solve the problems of an on-site emulsification and on-site sizing process commonly used in the existing ASA papermaking sizing process and solve the sizing process limitation caused by ASA hydrolysis. Compared with a traditional ASA emulsion emulsified and stabilized by a surfactant (such as starch) and an ASA emulsion emulsified and stabilized by solid particles (such as clay nanoparticles and modified particles thereof), the ASA emulsion prepared by the method of the present invention has the advantages that the surface sizing performance is obviously improved, and at the same time, the hydrolysis-resistant performance of the ASA can be greatly improved; and the preparation

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a micrograph of an ASA-A emulsion prepared according to Embodiment 2. FIG. 2 is a micrograph of an ASA-B emulsion prepared according to Embodiment 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The present invention will be further illustrated with reference to embodiments and drawings hereafter, but the present invention is not limited to the following embodiments.

[0024] Embodiment 1 Preparation of hydrolysis-resistant dodecenyl succinic anhydride sizing agent (1) 1 weight part of CNC (diameter: 3 nm, and length: 100 nm) was dispersed in water to be prepared into a dispersion with a mass percentage of 0.05%, and 2 weight parts of acetone, 10 weight parts of ammonia monohydrate and 0.02 weight part of cetyltrimethylsiloxane were added for mixing. Ultrasonic dispersion was performed for 1 h at 25°C and 500 W to obtain a mixed solution I. 0.05 weight part of perfluorooctyltriethoxysilane was added into the mixed solution I. Ultrasonic dispersion was continuously performed for 1 h to obtain a mixed solution II. The mixed solution II was dried in vacuum at 65°C to obtain CNC-R powder. (2) 1 weight part of CNC-R powder and 20 weight parts of perfluorohexane were mixed. Ultrasonic dispersion was performed for 1 h at 25°C and 500 W. 200 weight parts of dodecenyl succinic anhydride were added for mixing. Ultrasonic emulsification was continuously performed for 15 min to obtain an ASA-A emulsion. (3) 2 weight parts of ASA-A emulsion and 1 weight part of sodium dodecyl sulfonate aqueous solution with a mass concentration of 0.1% were mixed. Ultrasonic emulsification was performed for 15 min at 25°C and 500 W to obtain an ASA-B emulsion, i.e., the hydrolysis-resistant alkenyl succinic anhydride sizing agent.

[0025] Embodiment 2 Preparation of hydrolysis-resistant hexadecenyl succinic anhydride sizing agent (1) 1 weight part of CNC (diameter: 5 nm, and length: 220 nm) was dispersed in water to be prepared into a dispersion with a mass percentage of 1%, and 10 weight parts of acetone, 20 weight parts of ammonia monohydrate and 0.2 weight part of cetyltrimethylsiloxane were added for mixing. Ultrasonic dispersion was performed for 1 h at 25°C and 1000 W to obtain a mixed solution I. 0.1 weight part of perfluorooctyltriethoxysilane was added into the mixed solution I. Ultrasonic dispersion was continuously performed for 1 h to obtain a mixed solution II. The mixed solution II was dried in vacuum at 65°C to obtain CNC-R powder.

(2) 1 weight part of CNR-R powder and 60 weight parts of perfluorohexane were mixed. Ultrasonic dispersion was performed for 1 h at 25°C and 1000 W. 60 weight parts of hexadecenyl succinic anhydride were added for mixing. Ultrasonic emulsification was continuously performed for 15 min to obtain an ASA-A emulsion. A micrograph of the ASA-A emulsion was as shown in FIG. 1: a continuous phase is perfluorohexane, liquid drops were ASA emulsion (O/O) liquid drops coated with the perfluorohexane, the interface component composition of the liquid drops was modified CNC-R particles grafted with long chain alkyl groups [-(CH2)«CH3] and long chain perfluoroalkane groups [-(CH2)x(CF2)xCF3] on surfaces, and the particles could be used as an interface particle stabilizing agent for effectively stabilizing the perfluorohexane and an ASA oil phase to form the ASA-A emulsion with an average liquid drop diameter being about 1 um.

[0026] (3) 1 weight part of ASA-A emulsion and 5 weight parts of sodium dodecyl sulfonate aqueous solution with a mass concentration of 0.5% were mixed. Ultrasonic emulsification was performed for 15 min at 25°C and 1000 W to obtain an ASA-B emulsion, i.e, the hydrolysis-resistant alkenyl succinic anhydride sizing agent. A micrograph of the ASA-B emulsion was as shown in FIG. 2: the sizing agent emulsion used the sodium dodecyl sulfonate aqueous solution as a continuous phase, and an ASA-perfluorooctane emulsion was dispersed in the solution in a form of spherical dispersed liquid drops; the ASA was coated by the perfluorooctane, the CNC-R was adsorbed in an oil-oil interface position between the ASA and the perfluorooctane in a form of solid particles to form an oil-oil emulsion; and liquid drops of the finally obtained ASA emulsion avoided the contact between the ASA and a water phase due to the coating of an outer layer oil phase, so that the goal of avoiding hydrolysis was achieved.

[0027] Embodiment 3 Preparation of hydrolysis-resistant alkenyl succinic anhydride sizing agent (1) 2 weight parts of CNC (diameter: 10 nm, and length: 500 nm) were dispersed in water to be prepared into a dispersion with a mass percentage of 2%, and 1 weight part of acetone, 2 weight parts of ammonia monohydrate and 0.6 weight part of cetyltrimethylsiloxane were added for mixing. Ultrasonic dispersion was performed for 1 h at 25°C and 3000 W to obtain a mixed solution I. 0.4 weight part of perfluorooctyltriethoxysilane was added into the mixed solution I. Ultrasonic dispersion was continuously performed for 1 h to obtain a mixed solution II. The mixed solution II was dried in vacuum at 65°C to obtain CNC-R powder. (2) 1 weight part of CNC-R powder and 100 weight parts of perfluorohexane were mixed. Ultrasonic dispersion was performed for 1 h at 25°C and 3000 W. 10 weight parts of octadecenyl succinic anhydride were added for mixing. Ultrasonic emulsification was continuously performed for 15 min to obtain an ASA-A emulsion. (3) 1 weight part of ASA-A emulsion and 10 weight parts of sodium dodecyl sulfonate aqueous solution with a mass concentration of 1% were mixed. Ultrasonic emulsification was performed for 15 min at 25°C and 3000 W to obtain an ASA-B emulsion, i.e, the hydrolysis-resistant alkenyl succinic anhydride sizing agent.

[0028] Comparative example 1 A stable alkenyl succinic anhydride papermaking sizing agent emulsion (CN

200810017130.0) was prepared by using micro flocculant polymers of anionic and cationic inorganic nanoparticles as an emulsifying and stabilizing agent. A specific method was a method adopted in Embodiment 4 of this patent. The specific method included the following steps: 2 g of sodium fluoride modified sodium bentonite (the original soil was taken from Liaoning) and 0.02 g of hydrotalcite with interlayer anions being CI ions were dispersed into 40 mL of deionized water to be prepared into an ASA emulsifier, and a solid content of the emulsifier was 4.8%; and 20 g of industrial product ASA was weighed, the above prepared emulsifier was mixed with the ASA, an oil-water proportion was kept to be 1:2, and emulsification was performed for 3 min by using a shearing emulsifying machine at a rotating speed of 10000 r/min. The prepared ASA emulsion was a uniform milk white O/W emulsion.

[0029] Application example Performance determination of hydrolysis-resistant alkenyl

’ LU500300 succinic anhydride sizing agent (1) Making of sized paper with pulp An internal sizing method was adopted for sizing. Before sizing, the sizing agent prepared in the embodiment or comparative example was diluted to 0.2%, a paper pulp concentration was adjusted to 1%, and 1% aluminum sulfate (a mass percentage relative to absolute dry paper pulp) was firstly added into paper pulp at a stirring speed of 500 rpm. Then, a pulp pH value was adjusted to 7.5 to 8.5 by 1 mol/L of sodium hydroxide solution. Next, the sizing agent (the consumption was 1%, a mass percentage relative to absolute dry paper pulp) and cationic polyacrylamide with the consumption of 0.03% (a mass percentage relative to absolute dry paper pulp) were sequentially added. Next, stirring was performed by a stirrer for 2 min at a shearing speed of 500 rpm. Still standing was performed for 30 s. Then, handsheets was made by a PTI paper making device (model: RK3AKWT), a quantitative index of the handsheets was 60 g/m?(T205 om-88, TAPPI), and a sheet making system selected a K-then method manual papermaking mode for papermaking with pulp according to standards ISO5289/2 and DIN54358. The made handsheets were dried at 105°C, a paper moisture content was balanced for 24 h at a room temperature, and an environment humidity was 50%.

[0030] (2) Measuring method of sizing value The sizing performance was elevated by measuring a sizing value of paper made with pulp (GB/T5405-2002). Before measurement, the paper was cut into a square paper sheet being 30x30 mm, and was put in an environment with a temperature of 25°C and a humidity of 50% for moisture content balance for 24 h. Four edges of the paper sheet were folded up to form a boat-shaped structure with a bottom surface area being about 20x20 mm. Then, the boat-shaped structure floated in an ammonium thiocyanate dilute solution with a concentration of 2%, a drop of 0.5 pL of ferric chloride solution with a mass concentration of 1% was dripped on an upper portion of the boat-shaped paper sheet by a dropper, and at the same time, timing was performed by a stopwatch. The timing was completed when a red spot occurred in a middle portion of the ferric chloride liquid drop. The time was the sizing value of this paper sample. Each of a front side and a back side of the tested sample was tested for times, and an average value was taken.

[0031] (3) Measurement method of average particle size of liquid drops Diameters of 100 emulsion liquid drops observed under a microscope were counted by a particle size statistic software of the optical microscope, an average value was taken and was the average particle size of the liquid drops.

[0032] Table 1 Performance of different sizing agents Average | Volume fraction (%) of emulsion Paper sizing value (s) particle phase size of After After After After After After Sample 2. liquid | placement | placement | placement | placement | placement | placement drops for 30 for 60 for 90 for 2 for 30 for 90 (um) days days days hours days days Embodiment | 4310.5 100 100 100 454+12 442+13 441+15 Embodiment > 2.6+0.3 100 100 100 51127 51316 510+14 Embodiment 3 5.1+0.2 100 100 100 496418 488+12 485+20 Comparative

2.5+0.5 | 35 30 30 55+4 Example According to Table 1, it could be known that the hydrolysis-resistant ASA sizing agent emulsion prepared by the present invention had the smaller average diameter of the liquid drops, the emulsion had no phase separated out and no emulsion breaking phenomenon after placement for 90 days, and this showed that the emulsion had good stability; the paper sizing value of sized paper was 454 to 511 s, and this showed that the sizing performance of the emulsion is good; and the paper sizing value of sized paper after the emulsion was placed for 90 days was 441 to 510 s, and the emulsion had good hydrolysis-resistant performance.

Claims

CLAIMS:

1. A preparation method of a hydrolysis-resistant alkenyl succinic anhydride sizing agent, comprising the following steps: (1) mixing a cellulose nanocrystalline (CNC) aqueous dispersion with acetone, ammonia monohydrate and cetyltrimethylsiloxane, and performing ultrasonic dispersion to obtain a mixed solution I; adding perfluorooctyltriethoxysilane into the mixed solution I, and performing ultrasonic dispersion to obtain a mixed solution II; and drying the mixed solution II to obtain CNC-R powder; (2) mixing the CNC-R powder with perfluorohexane, performing ultrasonic dispersion, adding alkenyl succinic anhydride for mixing, and performing ultrasonic emulsification to obtain an ASA-A emulsion; and (3) mixing the ASA-A emulsion with a sodium dodecyl sulfonate aqueous solution, and performing ultrasonic emulsification to obtain an ASA-B emulsion, 1e, the hydrolysis-resistant alkenyl succinic anhydride sizing agent.

2. The preparation method according to claim 1, wherein a diameter of the cellulose nanocrystalline is in a range of 3 to 10 nm, and a length is in a range of 100 to 500 nm; in the mixed solution I, a mass percentage of the cellulose nanocrystalline is in a range of

0.05 to 2%, a mass percentage of the acetone is in a range of 0.1 to 1%, and a mass percentage of the ammonia monohydrate is in a range of 0.5 to 2%; and a consumption of the cetyltrimethylsiloxane is 2 to 30% of the mass of the cellulose nanocrystalline, and a consumption of the perfluorooctyltriethoxysilane is 5 to 20% of the mass of the cellulose nanocrystalline.

3. The preparation method according to claim 1, wherein the alkenyl succinic anhydride is at least one of dodecyl to octadecyl alkenyl succinic anhydride monomers; a mass ratio of the CNC-R powder to perfluorooctane is 1:20-100; and a mass ratio of the alkenyl succinic anhydride to the perfluorooctane is 1:0.1-2.

4. The preparation method according to claim 1, wherein a mass ratio of the ASA-A emulsion to the sodium dodecyl sulfonate aqueous solution is 1:0.5-10; and a mass percentage of the sodium dodecyl sulfonate aqueous solution is in a range of 0.1 to 2%.

5. The preparation method according to claim 1, wherein the ultrasonic dispersion power is in a range of 500 to 3000 W.

6. A hydrolysis-resistant alkenyl succinic anhydride sizing agent obtained by adopting the preparation method according to any one of claims 1 to 5.

7. Application of the hydrolysis-resistant alkenyl succinic anhydride sizing agent according to claim 6 to preparation of water-resistant paper.