CN102191018A - Preparation method for low-melting-point paraffin microcapsules - Google Patents
Preparation method for low-melting-point paraffin microcapsules Download PDFInfo
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- CN102191018A CN102191018A CN2011100837737A CN201110083773A CN102191018A CN 102191018 A CN102191018 A CN 102191018A CN 2011100837737 A CN2011100837737 A CN 2011100837737A CN 201110083773 A CN201110083773 A CN 201110083773A CN 102191018 A CN102191018 A CN 102191018A
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Abstract
The invention relates to a preparation method for low-melting-point paraffin microcapsules, which is a one-step method and comprises the following steps of: dissolving poly(vinyl alcohol) in hot water, adding urea, adjusting the pH value of the solution with hydrochloric acid, and then adding low-melting-point paraffin; and adding a formaldehyde solution to the solution, carrying out reaction for 1-3 hours, adding resorcinol, continuing reaction for 1-3 hours, centrifugally filtering and vacuum-drying to obtain the low-melting-point paraffin microcapsules. The preparation method simplifies the preparation process for the paraffin microcapsule material, has the advantages of simple preparation process, uniform product shape, stable product performance and the like, and is easy to realize industrial production.
Description
Technical field
The present invention relates to a kind of phase-change material micro-capsule preparation methods, be specifically related to the one-step preppn process of low melt point paraffin microcapsule.
Background technology
Paraffin is a kind of phase change material of excellent property, and it has did not have cold and separate out phenomenon, and stable performance, nontoxic, no burn into are cheap, becomes the focus of research in the phase-transition heat-storage field.But in normal circumstances, its phase transition process is a solid-liquid phase change, so one of them major issue is the encapsulation of paraffin.
The method for packing of paraffin has three classes at present.The first kind is to be carrier with porous material inorganic materials such as pearlstone, expanded graphite, silicon-dioxide, adopts the vacuum suck method, and paraffin is fixed in interlayer structure or the micropore, is encapsulated.Second class is to be propping material with polyethylene, polypropylene, polystyrene or its multipolymer, adopts the method with the heating paraffin melt blending, the preparation shaping phase-change material.Above-mentioned two class methods have solved the flowability problem of phase change material in the solid-liquid phase change process, but its packaged type is the encapsulation of a kind of " style of opening ".In the solid-liquid phase change process, still there are the leakage and the migration of phase change material, and react, thereby cause weakening or disappearing of phase-transition heat-storage performance with the chemical substance of Working environment.The 3rd class is to be the wall material with urea-formaldehyde resin, urea-formaldehyde resin, polyureas, Resins, epoxy, methyl methacrylate etc., adopts microencapsulation technology to prepare the paraffin microcapsule phase change material.Compare with other method for packing of paraffin, fundamentally solved leakage and the migration of paraffin in the solid-liquid phase change process, and with problems such as the chemical substance of Working environment reacts, for the range of application that enlarges the paraffin microcapsule phase change material with improve the phase-transition heat-storage effect and have great importance.
2004, Chinese patent CN1513938A announced people's such as Wang Lixin patented invention, and it is phase change material that this patent adopts straight-chain paraffin, Fatty Alcohol(C12-C14 and C12-C18) and organic esters, is the wall material with melamine formaldehyde resin, preparation paraffin microcapsule phase change material.Zheng Lihui [preparation of micro encapsulation paraffin and thermal characteristics, applied chemistry, 2004,21(2): 200 ~ 202] is a raw material with urea-formaldehyde prepolymer and paraffin, utilizes situ aggregation method that paraffin has been carried out micro encapsulation.Chinese patent CN1657587A has announced Wang Shujun " a kind of preparation method of microcapsule encapsulation typing phase change material ", and this patent adopts situ aggregation method to use cyanurotriamide modified urea resin that the paraffin shaping phase-change material is carried out the microcapsule encapsulation.[the microcapsule preparation of MUF/ paraffin of Liu's magnitude, polymer material science and engineering, 2006,22(2): 235-238] reported with the low melt point paraffin to be core, cyanurotriamide modified urea resin is the wall material, has synthesized the low melt point paraffin phase-change material micro-capsule with situ aggregation method.But the following problem that the method for above-mentioned patent and bibliographical information exists has limited the suitability for industrialized production of paraffin microcapsule and has applied: (1) complex process.Urea-the formaldehyde prepolymer of synthesizing water-solubility joins performed polymer in the emulsion of phase change material then under the first weak basic condition again, makes performed polymer polycondensation take place and solidify to form micro encapsulation on the surface of phase change material under acidic conditions.(2) aftertreatment cost height.In the existing report, relate to ethanol, sherwood oil equal solvent for the washing of paraffin microcapsule, with respect to the urea and the formaldehyde of cheapness, the shared ratio of solvent is very high in the cost of paraffin microcapsule.
Summary of the invention
The purpose of this invention is to provide a kind of technology is simple, be easy to suitability for industrialized production, with low cost, good stability and the low melt point paraffin microcapsule of transformation temperature about 30 ℃ phase change material and preparation method.
Preparation method of the present invention is as follows:
(1) dissolving: polyvinyl alcohol is added in the still, add entry then, insulation, stirring are dissolved polyvinyl alcohol fully, and the concentration that makes polyvinyl alcohol solution is 2.5～4.0%, adds urea again;
(2) adjust pH: with hydrochloric acid conditioning solution pH value, the pulverizing paraffin of Jia Ruing again dissolves fully to paraffin;
(3) polymerization: controlled temperature adds concentration 36% formaldehyde solution at 70～90 ℃, reacts 1.0～2.5 hours, adds Resorcinol then, continues reaction; The weight ratio of described paraffin and film forming matter is 1.00 ~ 1.35:1, and wherein film forming matter comprises urea and formaldehyde, and the mol ratio of formaldehyde and urea is 1.2-1.4:1;
(4) filter: use the hot water wash product, centrifuging again, product is pulverized to Powdered.
Wherein processing condition are as follows:
The solvent temperature of polyvinyl alcohol is 70～90 ℃, and stirring velocity is 800～1200rmp.Paraffin adopts low melt point paraffin, and fusing point is at 25～35 ℃. the pH value of polymerization initial soln is 1.9 ~ 2.2, and stirring velocity is 800～1200rmp, and polymerization time is 1.0 ~ 2.5 hours; The weight ratio of Resorcinol and film forming matter is 4.0%～5.5%, and the reaction times is 1.0 ~ 2.0 hours, 70～90 ℃ of temperature of reaction; The paraffin microcapsule of preparation adopts 70～90 ℃ hot wash.
This preparation method directly allows urea and formaldehyde under acidic conditions polycondensation take place, and forming with the urea-formaldehyde resin is the microcapsule of wall material, and method is simple.Used raw material comprises low melt point paraffin, polyvinyl alcohol, urea, formaldehyde solution, hydrochloric acid, Resorcinol in present method, is technical grade, and water is tap water, has reduced the cost of low melt point paraffin microcapsule.
The transformation temperature of low melt point paraffin microcapsule and enthalpy of phase change are measured and are adopted differential scanning calorimeter.
Description of drawings
Fig. 1～Fig. 4 is the transformation temperature curve of synthetic low melt point paraffin microcapsule under the different technology conditions.
Embodiment
Embodiment 1
1.8kg polyvinyl alcohol adds in the still, and then adds 48kg water, keeps 80 ℃ of temperature, stirring velocity 800rmp, and polyvinyl alcohol is dissolved fully.Add 2.93kg urea again, fully dissolving.
With 0.5mol/L hydrochloric acid conditioning solution pH value to 2, be that 25～35 ℃ low melt point paraffin adds again with the fusing point of 6.3kg, 80 ℃ of temperature, stirring velocity 1200rmp observe by returning charge, dissolve fully to paraffin.
Temperature is controlled at 70 ℃, adds 36% formaldehyde solution of 5.52kg, reacted 2 hours, add the Resorcinol of 0.25kg then, continue reaction 1.5 hours.
Centrifuging, with 80 ℃ of hot water wash products three times, centrifuging again, product is pulverized to Powdered, 40 ℃ of heat content 63.6 J/g, phase transformation peak values, the transformation temperature curve is referring to Fig. 1.
Embodiment 2
1.3kg polyvinyl alcohol adds in the still, and then adds 48kg water, keeps 70 ℃ of temperature, stirring velocity 800rmp, and polyvinyl alcohol is dissolved fully, adds 2.93kg urea again, fully dissolving.
With 0.5mol/L hydrochloric acid conditioning solution pH value to 2, be that 25～35 ℃ low melt point paraffin paraffin adds again with the fusing point of 5.8kg, 80 ℃ of temperature, stirring velocity 1200rmp dissolve fully to paraffin.
Temperature is controlled at 70 ℃, adds 5.52kg formaldehyde solution, reacted 2 hours, add the Resorcinol of 0.22kg then, continue reaction 1.5 hours.
Centrifuging, with 80 ℃ of hot water wash products three times, centrifuging again, product is pulverized to Powdered, 44 ℃ of heat content 59.5 J/g, phase transformation peak values.The transformation temperature curve is referring to Fig. 2.
Embodiment 3
2.0kg polyvinyl alcohol adds in the still, and then adds 48kg water, keeps 90 ℃ of temperature, stirring velocity 800rmp, and polyvinyl alcohol is dissolved fully.Add 2.93kg urea again, fully dissolving.
With 0.5mol/L hydrochloric acid conditioning solution pH value to 2.1, be that 25～35 ℃ low melt point paraffin adds again with the pulverizing fusing point of 6.3kg, 80 ℃ of temperature, stirring velocity 1200rmp observe by returning charge, dissolve fully to paraffin.
Temperature is controlled at 70 ℃, adds 5.52kg formaldehyde solution, reacted 2 hours, add the Resorcinol of 0.25kg then, continue reaction 1.5 hours.
Centrifuging, with 80 ℃ of hot water wash products three times, centrifuging again, product is pulverized to Powdered, heat content 56.2 J/g, 44 ℃, the transformation temperature curve is referring to Fig. 3.
Embodiment 4
1.7kg polyvinyl alcohol adds in the still, and then adds 48kg water, keeps 80 ℃ of temperature, stirring velocity 800rmp, and polyvinyl alcohol is dissolved fully.Add 2.93kg urea again, fully dissolving.
With 0.5mol/L hydrochloric acid conditioning solution pH value to 1.9, be that 25～35 ℃ low melt point paraffin adds again with the pulverizing fusing point of 6.0kg, 80 ℃ of temperature, stirring velocity 1200rmp observe by returning charge, dissolve fully to paraffin.
Temperature is controlled at 80 ℃, adds 5.52kg formaldehyde solution, reacted 2 hours, add the Resorcinol of 0.25kg then, continue reaction 1.5 hours.
Centrifuging, with 80 ℃ of hot water wash products three times, centrifuging again, product is pulverized to Powdered, 76.1 J/g, 44 ℃, the transformation temperature curve is referring to Fig. 4.
Claims (6)
1. single stage method prepares the method for low melt point paraffin microcapsule, it is characterized in that, said method comprising the steps of:
(1) dissolving: polyvinyl alcohol is added in the still, add entry then, insulation, stirring are dissolved polyvinyl alcohol fully, and the concentration that makes polyvinyl alcohol solution is 2.5～4.0%, adds urea again;
(2) adjust pH: with hydrochloric acid conditioning solution pH value, the pulverizing paraffin of Jia Ruing again dissolves fully to paraffin;
(3) polymerization: controlled temperature adds concentration 36% formaldehyde solution at 70～90 ℃, reacts 1.0～2.5 hours, adds Resorcinol then, continues reaction; The weight ratio of described paraffin and film forming matter is 1.00 ~ 1.35:1, and wherein film forming matter comprises urea and formaldehyde, and the mol ratio of formaldehyde and urea is 1.2-1.4:1;
(4) filter: use the hot water wash product, centrifuging again, product is pulverized to Powdered.
2. single stage method according to claim 1 prepares the method for low melt point paraffin microcapsule, it is characterized in that described paraffin adopts low melt point paraffin, and fusing point is at 25～35 ℃.
3. single stage method according to claim 1 and 2 prepares the method for low melt point paraffin microcapsule, it is characterized in that: in described (1) step, the solvent temperature of polyvinyl alcohol is 70～90 ℃, and stirring velocity is 800～1200rmp.
4. single stage method according to claim 1 and 2 prepares the method for low melt point paraffin microcapsule, it is characterized in that: in described (2) step, the pH value of regulator solution is 1.9 ~ 2.2.
5. the method for preparing the low melt point paraffin microcapsule according to claim 1 or 2 described single stage method, it is characterized in that in described (3) step, Resorcinol weight is 4.0%～5.5% of film forming matter weight, and the reaction times is 1.0 ~ 2.0 hours, 70～90 ℃ of temperature of reaction.
6. single stage method according to claim 1 and 2 prepares the method for low melt point paraffin microcapsule, and the temperature that it is characterized in that the hot wash of described step (4) is 70～90 ℃.
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| CN2011100837737A CN102191018A (en) | 2011-04-02 | 2011-04-02 | Preparation method for low-melting-point paraffin microcapsules |
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| CN2011100837737A CN102191018A (en) | 2011-04-02 | 2011-04-02 | Preparation method for low-melting-point paraffin microcapsules |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105505357A (en) * | 2015-12-08 | 2016-04-20 | 中国石油天然气股份有限公司 | Chemical agent for improving quality of high-wax crude oil in situ and preparation method of chemical agent |
| CN109721311A (en) * | 2019-03-08 | 2019-05-07 | 陕西恒盛混凝土有限公司 | C45 mass concrete and its preparation process |
| CN110559957A (en) * | 2019-07-24 | 2019-12-13 | 广州市香港科大霍英东研究院 | phase change microcapsule with high blending fluidity and high phase change latent heat and preparation method thereof |
-
2011
- 2011-04-02 CN CN2011100837737A patent/CN102191018A/en active Pending
Non-Patent Citations (1)
| Title |
|---|
| 毛华军等: "一步法制备石蜡微胶囊的影响因素研究", 《2006年全国功能材料学术年会专辑》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105505357A (en) * | 2015-12-08 | 2016-04-20 | 中国石油天然气股份有限公司 | Chemical agent for improving quality of high-wax crude oil in situ and preparation method of chemical agent |
| CN109721311A (en) * | 2019-03-08 | 2019-05-07 | 陕西恒盛混凝土有限公司 | C45 mass concrete and its preparation process |
| CN110559957A (en) * | 2019-07-24 | 2019-12-13 | 广州市香港科大霍英东研究院 | phase change microcapsule with high blending fluidity and high phase change latent heat and preparation method thereof |
| CN110559957B (en) * | 2019-07-24 | 2020-10-27 | 广州市香港科大霍英东研究院 | Phase change microcapsule with high blending fluidity and high phase change latent heat and preparation method thereof |
| WO2021012302A1 (en) * | 2019-07-24 | 2021-01-28 | 广州市香港科大霍英东研究院 | Phase change microcapsule having high blending fluidity and high phase change latent heat and preparation method therefor |
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Application publication date: 20110921 |