CN109535444B - Bleaching process of hydroxyethyl cellulose - Google Patents
Bleaching process of hydroxyethyl cellulose Download PDFInfo
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- CN109535444B CN109535444B CN201811454498.3A CN201811454498A CN109535444B CN 109535444 B CN109535444 B CN 109535444B CN 201811454498 A CN201811454498 A CN 201811454498A CN 109535444 B CN109535444 B CN 109535444B
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- bleaching
- hydroxyethyl cellulose
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- caustic soda
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- 229920000663 Hydroxyethyl cellulose Polymers 0.000 title claims abstract description 57
- 239000004354 Hydroxyethyl cellulose Substances 0.000 title claims abstract description 57
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 title claims abstract description 57
- 238000004061 bleaching Methods 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 15
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 72
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 50
- 235000011121 sodium hydroxide Nutrition 0.000 claims abstract description 24
- 239000003381 stabilizer Substances 0.000 claims abstract description 24
- 239000002904 solvent Substances 0.000 claims abstract description 22
- 238000003756 stirring Methods 0.000 claims abstract description 13
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- 239000002253 acid Substances 0.000 claims abstract description 8
- 238000001816 cooling Methods 0.000 claims abstract description 8
- 238000001035 drying Methods 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 8
- 230000003472 neutralizing effect Effects 0.000 claims abstract description 8
- 238000005406 washing Methods 0.000 claims abstract description 8
- 238000007599 discharging Methods 0.000 claims abstract description 4
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical group [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 8
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical group CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- 159000000003 magnesium salts Chemical class 0.000 claims description 6
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 4
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 13
- 239000001913 cellulose Substances 0.000 abstract description 10
- 229920002678 cellulose Polymers 0.000 abstract description 10
- 239000000126 substance Substances 0.000 abstract description 8
- 238000000576 coating method Methods 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 3
- 239000011248 coating agent Substances 0.000 abstract description 2
- 230000001737 promoting effect Effects 0.000 abstract 1
- 239000000047 product Substances 0.000 description 27
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 238000005119 centrifugation Methods 0.000 description 4
- 150000003254 radicals Chemical class 0.000 description 4
- 238000005303 weighing Methods 0.000 description 4
- 239000005708 Sodium hypochlorite Substances 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 239000007844 bleaching agent Substances 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 229920000742 Cotton Polymers 0.000 description 1
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000003421 catalytic decomposition reaction Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000006266 etherification reaction Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007863 gel particle Substances 0.000 description 1
- 239000003349 gelling agent Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- -1 hydrogen peroxide ions Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 238000010525 oxidative degradation reaction Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000375 suspending agent Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J2301/08—Cellulose derivatives
- C08J2301/26—Cellulose ethers
- C08J2301/28—Alkyl ethers
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Detergent Compositions (AREA)
- Cosmetics (AREA)
Abstract
The invention relates to a bleaching process of hydroxyethyl cellulose, belonging to the technical field of cellulose and chemical materials. The invention solves the technical problems that the prior hydroxyethyl cellulose has poor bleaching effect and the viscosity is reduced more after bleaching. Dissolving flake caustic soda in a solvent in a reaction vessel, starting stirring, adding a stabilizer, adding hydroxyethyl cellulose after the stabilizer is dispersed and dissolved, adding hydrogen peroxide after the hydroxyethyl cellulose is dispersed, heating for bleaching, cooling after bleaching, neutralizing with acid until the pH value is 6.0-7.0, discharging, washing, centrifuging, drying and crushing to obtain a bleached product. The novel bleaching process is developed, has an obvious effect on bleaching hydroxyethyl cellulose, reduces the viscosity of the hydroxyethyl cellulose less, and plays a great role in promoting the quality improvement of daily chemicals and coating products.
Description
Technical Field
The invention belongs to the technical field of cellulose and chemical materials, and particularly relates to a bleaching process of hydroxyethyl cellulose.
Background
Hydroxyethyl cellulose (HEC) is nonionic cellulose single ether prepared from cotton fibers through processes of alkalization, ethylene oxide etherification and the like, and the HEC can be used as a coating agent, a binder, a cement and gypsum assistant, a thickening agent, a suspending agent, a medicinal auxiliary material, an antifogging agent, an oil well fracturing fluid, a gelling agent, a waterproof agent and the like due to the nonionic characteristic that the HEC does not react with positive ions and negative ions and has good compatibility, and is widely applied to the fields of coatings, petroleum, buildings, daily chemical industry, high polymer polymerization, textile industry and the like.
Due to the rapid development of paints and daily chemical products, the market not only requires excellent service performance, but also has strict requirements on the appearance, particularly the whiteness of high-end products for daily chemical and interior coatings is an important factor influencing the appearance, and the hydroxyethyl cellulose ether (HEC) serving as an important additive raw material has an important influence on the whiteness index of the paints and daily chemical products, so that the preparation of the HEC with the whiteness meeting the requirements of customers is very important. The method adopts hydrogen peroxide to bleach the yellow products in the production process, can improve the product quality and reduce the loss of waste materials in the production process.
The bleaching agent commonly used for bleaching the HEC comprises sodium hypochlorite and hydrogen peroxide, when the HEC is bleached by the sodium hypochlorite, the bleaching effect is poor, and the ash content and gel particles of a bleached product are increased. When the HEC is bleached by the hydrogen peroxide, the viscosity of the product is reduced greatly due to the strong oxidation effect of the hydrogen peroxide, so that the bleaching effect of the sodium hypochlorite and the hydrogen peroxide is poor, namely no effective process technology for bleaching the HEC product exists at present.
Disclosure of Invention
The invention solves the technical problems that the prior bleaching effect on hydroxyethyl cellulose is poor, and the viscosity is reduced more after bleaching.
The technical scheme for solving the problems is to provide a bleaching process of hydroxyethyl cellulose, which comprises the following steps:
dissolving flake caustic soda in a solvent in a reaction vessel, starting stirring, adding a stabilizer, adding hydroxyethyl cellulose after the stabilizer is dispersed and dissolved, adding hydrogen peroxide after the hydroxyethyl cellulose is dispersed, heating for bleaching, cooling after bleaching, neutralizing with acid until the pH value is 6.0-7.0, discharging, washing, centrifuging, drying and crushing to obtain a bleached product.
Wherein the mass ratio of the caustic soda flakes to the solvent is 0.1-0.4%, the mass ratio of the caustic soda flakes to the hydroxyethyl cellulose is 0.5-2.5%, and the mass ratio of the hydrogen peroxide to the hydroxyethyl cellulose is 2-10%.
Wherein the bleaching temperature is 45-75 ℃, and the bleaching time is 20-60 minutes.
Wherein the solvent is acetone.
Wherein the caustic soda flakes are solid sodium hydroxide and have the mass percentage of 98 percent.
Wherein the stabilizer is soluble magnesium salt, and the mass ratio of the soluble magnesium salt to the hydroxyethyl cellulose is 0.5-2%.
Preferably, the stabilizer is magnesium sulfate.
The invention has the beneficial effects that:
the invention develops a novel bleaching process, controls certain process parameters under the conditions of strong alkali, high temperature and the presence of a stabilizer, has obvious effect on bleaching hydroxyethyl cellulose, and reduces the viscosity of the bleached hydroxyethyl cellulose less.
Drawings
FIG. 1 is a comparison of hydroxyethyl cellulose before and after bleaching, where a is before bleaching and b is after bleaching.
Detailed Description
The hydrogen peroxide has a strong bleaching effect on the fiber, and the bleaching mechanism of the hydrogen peroxide has the following two statements:
1) earlier it was believed that the decomposition of hydrogen peroxide to produce nascent oxygen (O) has a bleaching effect on cellulose: h2O2→H2O + (O); however, scientific research proves that nascent oxygen (O) can oxidize cellulose to cause damage particularly under strong alkali and high temperature, but has no definite evidence on how much bleaching effect is.
2) Widely cited at home and abroad is the argument of pette ney (Peter Nay) in germany: the hydrogen peroxide decomposition is believed to cause bleaching of the fibers by hydrogen peroxide ions HOO-Since the main substance responsible for the oxidation of cellulose is the hydrogen peroxide radical HOO, the production of HOO is suppressed and HOO is caused to occur during the bleaching process-The generation is stable, so that the cellulose can be prevented from being oxidized, and a good bleaching effect can be obtained. In aqueous solution, hydrogen peroxide dissociates to produce HOO－I.e. H2O2→H++HOO－. Dissociation constant K in water20＝1.78×10－12From the above formula, HOO can be seen－The amount of (A) increases with increasing pH of the solution, whereas bleaching is carried out under alkaline conditions. However, as the alkali concentration increases, hydrogen peroxide decomposes to generate excessive amounts of HOO and HO radicals, and the radicals have extremely high activity, and thus have a bleaching effect on cellulose, but the cellulose is easily damaged by excessive amounts of radicals. Therefore, effective stabilizers must be added to the bleach liquor to inhibit excess free radical generation due to catalytic decomposition while increasing HOO－So as to prevent the HEC product from oxidative degradation and further play a good role in bleaching. HOO－Has an oxidation reaction with the fiber pigmentBleaching, decoloring and removing impurities. The reaction formula is as follows:
based on the above analysis, the present invention provides a bleaching process for hydroxyethyl cellulose, which specifically comprises the following steps:
dissolving flake caustic soda in a solvent in a reaction vessel, starting stirring, adding a stabilizer A, adding hydroxyethyl cellulose after the stabilizer A is dispersed and dissolved, adding hydrogen peroxide after the hydroxyethyl cellulose is dispersed, heating to a certain temperature for bleaching, keeping the temperature and stirring for a certain time, cooling to 30 ℃, neutralizing with acid until the PH is 6.0-7.0, discharging, washing, centrifuging, drying and crushing to obtain a bleached product.
Wherein the mass ratio of the caustic soda flakes to the solvent is 0.1-0.4%, the mass ratio of the caustic soda flakes to the hydroxyethyl cellulose is 0.5-2.5%, and the mass ratio of the hydrogen peroxide to the hydroxyethyl cellulose is 2-10%.
Wherein the bleaching temperature is 45-75 ℃, and the heat preservation time is 20-60 minutes.
Among them, acetone is preferred as the solvent.
Wherein, the flake caustic soda is preferably solid sodium hydroxide with the mass percentage of 98 percent.
Wherein the stabilizer is soluble magnesium salt, and the mass ratio of the soluble magnesium salt to the hydroxyethyl cellulose is 0.5-2%.
Preferably, the stabilizer is magnesium sulfate.
The invention is also applicable to the bleaching of other cellulose derivatives.
The invention is further illustrated and described by the following examples.
The hydroxyethyl cellulose product selected in the examples was yellow in color, had a whiteness of 54, a viscosity of 493mpa.s (2%, 25 ℃, LVT), a hydrogen peroxide concentration of 27.5% (m/m), and the stabilizer used was magnesium sulfate.
Example 1
Weighing 560g of solvent and 0.56g of flake caustic soda, dissolving the flake caustic soda in the solvent in a reaction vessel, starting stirring, adding 0.5g of stabilizer, adding 100g of hydroxyethyl cellulose after the stabilizer is dispersed and dissolved, adding 2g of hydrogen peroxide after the hydroxyethyl cellulose is dispersed, heating to 45 ℃, preserving heat and stirring for 30 min. Cooling to 30 ℃, and neutralizing with acid until the PH value is 6.0-7.0. Washing with solvent after centrifugation, centrifuging, drying and crushing to obtain a bleached product PHEC-1, wherein the performance data of the obtained product is shown in Table 1. From example 1, the product whiteness increased from 54 to 64, 18.5% over before bleaching.
TABLE 1
| Batch number | Whiteness degree | Viscosity (2%, 25 ℃, LVT) mpa.s |
| HEC (before bleaching) | 54 | 493 |
| PHEC-1 | 64 | 489 |
Example 2
Weighing 560g of solvent and 1.12g of flake caustic soda, dissolving the flake caustic soda in the solvent in a reaction vessel, starting stirring, adding 1g of stabilizer, adding 100g of hydroxyethyl cellulose after the stabilizer is dispersed and dissolved, dispersing the hydroxyethyl cellulose, finally adding 6g of hydrogen peroxide, heating to 60 ℃, preserving heat and stirring for 30 min. Cooling to 30 ℃, and neutralizing with acid until the PH value is 6.0-7.0. Washing with solvent after centrifugation, centrifuging, drying and crushing to obtain the bleached product PHEC-2. The performance data of the resulting product is shown in Table 2, and the comparison before and after bleaching is shown in FIG. 1. From the data of example 2, it can be seen that the product whiteness increased from 54 to 78, and the product whiteness increased by 44.4%.
TABLE 2
Example 3
Weighing 560g of solvent and 2.24g of flake caustic soda, dissolving the flake caustic soda in the solvent in a reaction vessel, starting stirring, adding 2g of stabilizer, adding 100g of hydroxyethyl cellulose after the stabilizer is dispersed and dissolved, dispersing the hydroxyethyl cellulose, finally adding 8g of hydrogen peroxide, heating to 60 ℃, preserving heat and stirring for 30 min. Cooling to 30 ℃, and neutralizing with acid until the PH value is 6.0-7.0. Washing with solvent after centrifugation, centrifuging, drying and crushing to obtain a bleached product PHEC-3, wherein the performance data of the obtained product is shown in Table 3. From the data of example 3, it can be seen that the product whiteness increased from 54 to 77, and the product whiteness increased by 42.6%.
TABLE 3
| Batch number | Whiteness degree | Viscosity (2%, 25 ℃, LVT) mpa.s |
| HEC (before bleaching) | 54 | 493 |
| PHEC-3 | 77 | 386 |
Example 4
Weighing 560g of solvent and 2.24g of flake caustic soda, dissolving the flake caustic soda in the solvent in a reaction vessel, starting stirring, adding 100g of relatively yellow hydroxyethyl cellulose, dispersing the hydroxyethyl cellulose, finally adding 6g of hydrogen peroxide, heating to 60 ℃, preserving heat and stirring for 30 min. Cooling to 30 deg.C, and neutralizing with acid to pH of 6.0-7.0. Washing with solvent after centrifugation, centrifuging, drying and crushing to obtain the bleached product PHEC-4. Example 4 differs from example 3 in that example 4 has no added stabilizer. The performance data of the product obtained are shown in Table 4, and it is evident from example 4 that the whiteness of the product is improved by 7%, the product is still yellowish and the viscosity of the product is reduced more.
TABLE 4
| Batch number | Whiteness degree | Viscosity (2%, 25 ℃, LVT) mpa.s |
| HEC (before bleaching) | 54 | 493 |
| PHEC-4 | 58 | 36 |
Claims (3)
1. The bleaching process of the hydroxyethyl cellulose is characterized by comprising the following steps: dissolving flake caustic soda in a solvent in a reaction vessel, starting stirring, adding a stabilizer, adding hydroxyethyl cellulose after the stabilizer is dispersed and dissolved, adding hydrogen peroxide after the hydroxyethyl cellulose is dispersed, heating for bleaching, cooling after bleaching, neutralizing with acid until the pH value is 6.0-7.0, discharging, washing, centrifuging, drying and crushing to obtain a bleached product; the mass ratio of the flake caustic soda to the solvent is 0.1-0.4%, the mass ratio of the flake caustic soda to the hydroxyethyl cellulose is 0.5-2.5%, and the mass ratio of the hydrogen peroxide to the hydroxyethyl cellulose is 2-10%; the bleaching temperature is 45-75 ℃, and the bleaching time is 20-60 minutes; the stabilizer is soluble magnesium salt, and the mass ratio of the soluble magnesium salt to the hydroxyethyl cellulose is 0.5-2%; the solvent is acetone.
2. The process of bleaching hydroxyethylcellulose according to claim 1, wherein: the flake caustic soda is solid sodium hydroxide and accounts for 98 percent by mass.
3. The process for bleaching hydroxyethylcellulose according to claim 1 or 2, characterized in that: the stabilizer is magnesium sulfate.
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| CN201811454498.3A CN109535444B (en) | 2018-11-30 | 2018-11-30 | Bleaching process of hydroxyethyl cellulose |
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| ES2379799T3 (en) * | 2004-08-31 | 2012-05-03 | Hercules Incorporated | Procedure for preparing low molecular weight cationic polygalactomannan with reduced odor |
| AU2007344425B2 (en) * | 2007-01-16 | 2010-08-05 | Unilever Plc | Bleaching of substrates |
| CN101581034A (en) * | 2008-05-14 | 2009-11-18 | 哈尔滨理工大学 | Biologically-aided totally-chlorine-free bleaching technology of flax cloth or fiber |
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| CN105350277A (en) * | 2015-12-16 | 2016-02-24 | 上海市纺织科学研究院 | Low-temperature bleaching formula and technology for cellulose fiber spunlace nonwoven fabric |
| CN106120295B (en) * | 2016-08-16 | 2019-04-09 | 绍兴市荣士达衬布有限公司 | A kind of glycerol-sodium carboxymethylcellulose Compositional type hydrogen peroxide bleaching stabilizer and its application |
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