Method for continuously producing aqueous antioxidant emulsion
Technical Field
The invention relates to the technical field of fine chemical engineering, in particular to a method for continuously producing aqueous antioxidant emulsion.
Background
The water-based antioxidant is a novel and environment-friendly auxiliary agent, and is mainly applied to the fields of synthetic resin, rubber, water-based paint and water-based adhesive. The global demand for aqueous antioxidants is over 30 million tons/year, and with the development of large-scale petrochemical refining integration projects, the demand for aqueous antioxidants is increasing day by day. The dispersed phase of the aqueous antioxidant is water and does not contain any harmful solvent, and the dispersed phase is antioxidant tiny particles (which can be solid phase or liquid phase), the apparent state of the antioxidant is similar to milk in daily life, and the antioxidant can be classified as aqueous dispersion or colloid. Besides environmental protection, the water-based antioxidant has the greatest advantages that the antioxidant is small in size, so that the dispersibility is easy, and the good dispersion state provides guarantee for the high antioxidant efficiency of the antioxidant.
At present, the preparation technology of the aqueous antioxidant is a batch method, for example, patent CN102181072A discloses a method for preparing the aqueous antioxidant, which is to premix various antioxidants, add a solvent to completely dissolve the antioxidants in the solvent under a heating condition, add an emulsifier to disperse under the action of a high-speed homogenizer, and finally prepare an aqueous antioxidant emulsion.
Patent CN111909528A discloses an antioxidant emulsion which can be emulsified and stabilized at normal temperature and its preparation, the process is to mix compound antioxidant, emulsifier and solvent, make the antioxidant dissolve in the solvent, add water to stir and disperse, prepare the antioxidant emulsion product finally, its characteristic lies in that the process does not heat up, the disadvantage lies in using organic solvents such as acetone, etc.. The preparation method of the aqueous antioxidant disclosed in the patent CN102924748A also adds an organic solvent as a diluent and adopts a high-speed shearing method for mixing. The patent CN107805320A is still a batch technology, and utilizes the dissolution balance of an antioxidant in a continuous phase to prepare the aqueous antioxidant on the basis of high-speed shearing.
In addition to the preparation process of the aqueous antioxidant reported in the above patent, antioxidant powder is usually directly ground in a ball mill or a sand mill, and the like, and the method has the characteristics of long grinding time (more than 10 hours), high energy consumption, high price of used grinding consumables, and no contribution to large-scale industrial production. At present, antioxidant manufacturers at home and abroad use an intermittent method to produce water-based antioxidant products, and no report on continuous method for producing antioxidant emulsion is found.
Disclosure of Invention
In view of the above, the invention provides a method for continuously producing aqueous antioxidant emulsion, which can freely combine antioxidant components to realize continuous production of various antioxidant emulsion products.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for continuously producing an aqueous antioxidant emulsion comprising the steps of:
(1) Uniformly mixing at least one antioxidant in a high-speed stirrer, directly adding the mixture into a double-screw extruder, and starting the double-screw extruder to melt and blend the antioxidant to obtain a molten antioxidant;
(2) Adding an emulsifier into a feeding port at the tail end of the double-screw extruder to fully mix the emulsifier with a molten antioxidant, directly adding the antioxidant paste in a water-in-oil state obtained after mixing into a stirring tank, and simultaneously adding deionized water into the stirring tank to control the retention time of the antioxidant paste in the stirring tank to be 5-30 min, so as to obtain the antioxidant emulsion after the retention time is reached.
Preferably, in the above method for continuously producing an aqueous antioxidant emulsion, the mass ratio of the antioxidant to the emulsifier is 100: (1-20).
The beneficial effects of the above technical scheme are: the whole preparation process of the aqueous antioxidant does not use any organic solvent, the continuous production is realized in the preparation process of the aqueous antioxidant, the particle size of the prepared aqueous antioxidant emulsion is small, the dispersion effect is good, and the whole process is safe, environment-friendly and efficient.
Preferably, in the above method for continuously producing the aqueous antioxidant emulsion, the temperature setting value of each section of the twin-screw extruder is 5-20 ℃ higher than the eutectic point of the antioxidant.
The beneficial effects of the above technical scheme are: aiming at a single-component antioxidant, the eutectic point of the antioxidant is the melting point or the highest temperature of the melting range of the antioxidant; the eutectic point of the antioxidants is defined as the point of inflection where the viscosity increases suddenly after the composite antioxidants are completely melted and fully dissolved, and the eutectic point can be calibrated by using a temperature and viscosity change curve.
Preferably, in one of the above-mentioned methods for continuously producing an aqueous antioxidant emulsion, the temperature of the agitation tank is not lower than the eutectic point of the antioxidant, and if the temperature of the agitation tank is lower than the eutectic point of the antioxidant, it appears that the antioxidant paste is difficult to disperse in water, and therefore, the temperature of the agitation tank of the present invention is set to 40 to 90 ℃.
Preferably, in the above method for continuously producing the aqueous antioxidant emulsion, the speed of adding the antioxidant paste into the stirring tank and the speed of adding the deionized water into the stirring tank in the step (2) need to be set according to the solid content requirement of the final aqueous antioxidant product. The feed rate ratio of water to antioxidant paste can be determined according to the following formula: n =1/S-1, where S is the desired solids content of the final aqueous antioxidant and N is the feed rate of water relative to the antioxidant paste. If the solid content of the final antioxidant product is required to be 50%, the adding speed of the paste antioxidant is equal to the adding speed of water; if the solid content of the final aqueous antioxidant product is required to be 40%, the adding speed of water is 1.5 times of that of the antioxidant paste; if the solid content of the final antioxidant product is required to be 25 percent, the adding speed of the water is 3 times of that of the antioxidant paste. Generally, the speed of adding the antioxidant paste into the stirring tank is preferably 5 to 20 parts per minute, and the speed of adding the deionized water into the stirring tank is 5 to 20 minutes.
Preferably, in one of the above methods for continuously producing an aqueous antioxidant emulsion, the antioxidant is one or more of a phenolic antioxidant and a thioether antioxidant.
Preferably, in one of the above-mentioned methods for continuously producing an aqueous antioxidant emulsion, the antioxidant includes CPL (p-cresol and dicyclopentadiene butylated product), 1076 (n-octadecyl- β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), 1010 (pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], 3114 (1, 3,5- (di-tert-butyl-4-hydroxybenzyl) s-triazine-2, 4,6- (1H, 3H, 5H) trione), GM (2-tert-butyl-6- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -4-methylphenyl acrylate), 245 (triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate), 300 (4, 4 'thiobis (6-tert-butyl-3 methylphenol)), DLTP (didecylthiodipropionate), DSTP (3, 3' -dioctadecyl thiodipropionate).
Preferably, in the above method for continuously producing the aqueous antioxidant emulsion, the emulsifier is obtained by compounding an anionic emulsifier and a nonionic emulsifier.
The beneficial effects of the above technical scheme are: the anionic emulsifier and the nonionic emulsifier are compounded, so that electrostatic repulsion and steric hindrance between the emulsified antioxidant particles can be improved, the stability of the antioxidant emulsion is improved, and the antioxidant emulsion is not layered or separated out in the long-term storage process.
Preferably, in the above method for continuously producing the aqueous antioxidant emulsion, the anionic emulsifier is one or a mixture of several of disproportionated abietic acid soap, potassium oleate soap, sodium oleate soap, potassium ricinoleate soap, potassium fatty acid soap, potassium stearate soap, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, fatty acid polyoxyethylene ether sulfate and fatty acid polyoxyethylene ether sulfonate;
the nonionic emulsifier is one or more of polyvinyl alcohol, polyethylene glycol, isomeric tridecanol polyoxyethylene ether, castor oil and ethylene oxide polymer (such as El-20, el-40, HEL-20, HEL-40), polyethylene glycol oleate, polyethylene glycol fatty acid ester, and Tween 80.
The antioxidant and the emulsifier are matched according to the principle that HLB values are close, generally, the closer the HLB value of the composite emulsifier and the HLB value of the antioxidant is, the stronger the emulsifying capacity of the emulsifier is, and the smaller and more stable the particle size of the finally prepared aqueous antioxidant emulsion product is.
Preferably, in the above method for continuously producing an aqueous antioxidant emulsion, further comprising the step (3): discharging the antioxidant emulsion at the speed of 10-40 parts/min, cooling and packaging.
According to the technical scheme, compared with the prior art, the invention discloses a method for continuously producing the water-based antioxidant emulsion, the antioxidant is extruded and blended by a double-screw extruder, the antioxidant is changed into a melt uniform state in the process, the composite emulsifier is added at the feed port of the extruder screw to be fully mixed with the antioxidant in the extruder to form the antioxidant paste in a water-in-oil state, and the obtained antioxidant paste is added into water to be simply dispersed, so that the water-based antioxidant emulsion product can be obtained.
The method is characterized in that a double-screw extruder is used for melting the antioxidant product, the antioxidant product and an emulsifier are fully blended, the mixing of an oil phase and a water phase is realized inside the extruder, the antioxidant paste with a water-in-oil structure is prepared, then the antioxidant paste is secondarily dispersed in water, the conversion of the antioxidant paste from a water-in-oil state to an oil-in-water state is realized, and finally the water-based antioxidant product is prepared.
The whole process of the invention does not use any solvent, the process can realize continuous production, the product has small particle size, low viscosity and good emulsion stability, the method can be freely combined with the antioxidant, and the continuous production of various antioxidant emulsion products can be realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a process flow chart of the continuous method for producing the aqueous antioxidant emulsion.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The method comprises the steps of carrying out melt blending on the antioxidant by using a double-screw extruder, adding a composite emulsifier into a feeding port of the extruder, uniformly mixing the emulsifier and the antioxidant under the action of a screw to form a melt blending body of the antioxidant, namely forming the water-in-oil antioxidant, and then adding the water-in-oil antioxidant into water to stir and disperse to realize phase inversion, so as to obtain the water-based antioxidant emulsion. The invention is characterized in that no solvent is used in the whole process, and the method can be used for continuous production, does not use high-speed grinding or shearing, has low energy consumption and is suitable for large-scale industrial production.
Example 1
(1) After mixing the composite antioxidant 311460 parts and antioxidant DSTP40 parts in a high-speed stirrer, directly adding the mixture into a double-screw extruder, setting the temperature of each section of the double-screw extruder at 110 ℃, and starting the double-screw extruder to melt and blend the antioxidant;
(2) Adding 10 parts of emulsifier (containing 8 parts of disproportionated rosin acid soap, 1 part of isomeric tridecanol polyoxyethylene ether and EL-201 parts) into a feeding port at the tail end of an extruder, fully mixing the emulsifier with a molten antioxidant, directly adding an antioxidant paste obtained after mixing in a water-in-oil state into a stirring tank with stirring temperature of 60 ℃, wherein the adding speed of the antioxidant paste at the tail end of a double screw is 20 parts/min, adding deionized water into the stirring tank at the speed of 20 parts/min, and controlling the retention time of the antioxidant paste in the stirring tank to be 5min, so as to obtain an antioxidant emulsion product after the retention time is reached;
(3) And discharging the prepared antioxidant emulsion product at the speed of 40 parts/min, cooling and packaging to obtain an antioxidant emulsion commodity.
Example 2
(1) Mixing 101030 parts of composite antioxidant, 107630 parts of antioxidant and 40 parts of antioxidant DLTP in a high-speed stirrer, directly adding the mixture into a double-screw extruder, setting the temperature of each section of the double-screw extruder to 90 ℃, and starting the double-screw extruder to melt and blend the antioxidant;
(2) Adding 10 parts of emulsifier (comprising 4 parts of potassium oleate, 3 parts of potassium fatty acid, 1 part of polyvinyl alcohol and HEL-402 parts) into a feeding port at the tail end of an extruder, fully mixing the emulsifier with a molten antioxidant, directly adding the obtained antioxidant paste in a water-in-oil state into a stirring tank with stirring temperature of 50 ℃, adding 15 parts/min of the antioxidant paste at the tail end of a double screw, adding 15 parts/min of deionized water into the stirring tank, controlling the retention time of the antioxidant paste in the stirring tank to be 5min, and obtaining an antioxidant emulsion product after the retention time is reached;
(3) Discharging the prepared antioxidant emulsion product at the speed of 30 parts/min, cooling and packaging to obtain an antioxidant emulsion commodity.
Example 3
(1) Mixing 2450 parts of a composite antioxidant, 40 parts of a CPL antioxidant and 30 parts of a DSTP antioxidant in a high-speed stirrer, then directly adding the mixture into a double-screw extruder, setting the temperature of each section of the double-screw extruder to be 90 ℃, and starting the double-screw extruder to melt and blend the antioxidant;
(2) Adding 20 parts of emulsifier (10 parts of potassium stearate, 3 parts of potassium oleate, 5 parts of polyvinyl alcohol and 2 parts of polyethylene glycol stearate) into a feeding port at the tail end of an extruder, fully mixing the emulsifier with a molten antioxidant, directly adding the obtained antioxidant paste in a water-in-oil state into a stirring tank with stirring temperature of 60 ℃, adding 10 parts/min of the antioxidant paste at the tail end of a double screw, adding 10 parts/min of deionized water into the stirring tank, controlling the retention time of the antioxidant paste in the stirring tank to be 10min, and obtaining an antioxidant emulsion product after the retention time is reached;
(3) Discharging the prepared antioxidant emulsion product at the speed of 20 parts/min, cooling and packaging to obtain the antioxidant emulsion commodity.
Example 4
(1) 100 parts of a composite antioxidant CPL is directly added into a double-screw extruder after being mixed in a high-speed stirrer, the temperature of each section of the double-screw extruder is set to be 120 ℃, and the double-screw extruder is started to melt and blend the antioxidant;
(2) Adding 8 parts of emulsifier (comprising 3 parts of potassium ricinoleate, 3 parts of potassium stearate, 1 part of polyvinyl alcohol and 1 part of glycol oleate) into a feeding port at the tail end of an extruder, fully mixing the emulsifier with a molten antioxidant, directly adding an antioxidant paste obtained after mixing in a water-in-oil state into a stirring tank with stirring temperature of 80 ℃, wherein the adding speed of the antioxidant paste at the tail end of a double screw is 5 parts/min, adding deionized water into the stirring tank at the speed of 5 parts/min, controlling the retention time of the antioxidant paste in the stirring tank to be 10min, and obtaining an antioxidant emulsion product after the retention time is reached;
(3) Discharging the prepared antioxidant emulsion product at the speed of 10 parts/min, cooling and packaging to obtain the antioxidant emulsion commodity.
The aqueous antioxidant products obtained in the above examples were tested for their average particle size and potential using a laser particle sizer (ZS 90) of malvern britain, their viscosity using a rotational viscometer (LVDV) of shanghai Jingtian, and their centrifugation at 3000rpm for 30min using a high-speed centrifuge of shanghai centrifuge research, and the results obtained are shown in table 1 below.
Table 1 examples 1-4 sample test results
Sample name
|
Average particle diameter (nm)
|
Zeta potential (mV)
|
Viscosity (CPS)
|
Centrifugal stability
|
Example 1
|
247
|
-43
|
280
|
Not delaminating
|
Example 2
|
265
|
-39
|
189
|
Not layering
|
Example 3
|
207
|
-30
|
190
|
Not delaminating
|
Example 4
|
318
|
-52
|
210
|
Not layering |
Comparative example 1
The aqueous antioxidant product is prepared according to the formula composition of the embodiment 3 by the method disclosed by CN111909528A, the particle size of the obtained aqueous antioxidant emulsion is 1.2-4 um, and the layering phenomenon appears after centrifugation, which proves that the emulsion has general stability.
Comparative example 2
Grinding and emulsifying the antioxidant and the emulsifier in the embodiment 4 by a sand mill for 12 hours, wherein the formula composition and other steps are the same as those in the embodiment 4, the particle size of the finally obtained aqueous antioxidant emulsion is 560nm, and the layering phenomenon appears after centrifugation, which proves that the emulsion has general stability.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the scheme disclosed by the embodiment, the scheme corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.