CN116284990B - Method and device for recycling silicone rubber - Google Patents
Method and device for recycling silicone rubber Download PDFInfo
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- CN116284990B CN116284990B CN202310329798.3A CN202310329798A CN116284990B CN 116284990 B CN116284990 B CN 116284990B CN 202310329798 A CN202310329798 A CN 202310329798A CN 116284990 B CN116284990 B CN 116284990B
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- 229920002379 silicone rubber Polymers 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 48
- 239000004945 silicone rubber Substances 0.000 title claims abstract description 30
- 238000004064 recycling Methods 0.000 title claims abstract description 15
- 239000002699 waste material Substances 0.000 claims abstract description 50
- 239000003054 catalyst Substances 0.000 claims abstract description 49
- 239000002245 particle Substances 0.000 claims abstract description 48
- 238000002386 leaching Methods 0.000 claims abstract description 47
- 238000010438 heat treatment Methods 0.000 claims abstract description 40
- 239000002131 composite material Substances 0.000 claims abstract description 37
- 238000001035 drying Methods 0.000 claims abstract description 35
- 239000002904 solvent Substances 0.000 claims abstract description 34
- 239000002253 acid Substances 0.000 claims abstract description 22
- 238000006243 chemical reaction Methods 0.000 claims abstract description 21
- 239000007791 liquid phase Substances 0.000 claims abstract description 20
- 239000011259 mixed solution Substances 0.000 claims abstract description 19
- 238000002791 soaking Methods 0.000 claims abstract description 17
- 239000000243 solution Substances 0.000 claims abstract description 16
- 238000010992 reflux Methods 0.000 claims abstract description 14
- 238000003756 stirring Methods 0.000 claims abstract description 14
- 238000005507 spraying Methods 0.000 claims abstract description 13
- 238000000498 ball milling Methods 0.000 claims abstract description 12
- 238000004140 cleaning Methods 0.000 claims abstract description 12
- 238000007873 sieving Methods 0.000 claims abstract description 12
- 238000001914 filtration Methods 0.000 claims abstract description 11
- 239000012071 phase Substances 0.000 claims abstract description 11
- 230000002378 acidificating effect Effects 0.000 claims abstract description 9
- 238000002137 ultrasound extraction Methods 0.000 claims abstract description 9
- 238000002390 rotary evaporation Methods 0.000 claims abstract description 7
- 239000006228 supernatant Substances 0.000 claims abstract description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical group OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 123
- JOXIMZWYDAKGHI-UHFFFAOYSA-N p-toluenesulfonic acid Substances CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims description 62
- WBIQQQGBSDOWNP-UHFFFAOYSA-N 2-dodecylbenzenesulfonic acid Chemical compound CCCCCCCCCCCCC1=CC=CC=C1S(O)(=O)=O WBIQQQGBSDOWNP-UHFFFAOYSA-N 0.000 claims description 32
- 229940060296 dodecylbenzenesulfonic acid Drugs 0.000 claims description 32
- BIGPRXCJEDHCLP-UHFFFAOYSA-N ammonium bisulfate Chemical compound [NH4+].OS([O-])(=O)=O BIGPRXCJEDHCLP-UHFFFAOYSA-N 0.000 claims description 27
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 20
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical group CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 16
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 10
- 239000001569 carbon dioxide Substances 0.000 claims description 10
- 238000007599 discharging Methods 0.000 claims description 9
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 2
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- 125000005489 p-toluenesulfonic acid group Chemical group 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- 238000005336 cracking Methods 0.000 abstract description 9
- 238000003912 environmental pollution Methods 0.000 abstract description 4
- 238000011084 recovery Methods 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 25
- 238000002360 preparation method Methods 0.000 description 10
- 230000008569 process Effects 0.000 description 10
- 239000002184 metal Substances 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 229910021645 metal ion Inorganic materials 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000003377 acid catalyst Substances 0.000 description 2
- 238000004523 catalytic cracking Methods 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 2
- 238000005485 electric heating Methods 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000008707 rearrangement Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000004227 thermal cracking Methods 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
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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
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
- C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/04—Disintegrating plastics, e.g. by milling
-
- 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
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
- C08J11/12—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by dry-heat treatment only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0293—Dissolving the materials in gases or liquids
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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
- C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
- C08J2383/04—Polysiloxanes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Polymers & Plastics (AREA)
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- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Sustainable Development (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The invention relates to a method and a device for recycling silicon rubber, which can effectively reduce the usage amount of an acidic catalyst in the later stage and solve the problems of large usage amount of waste acid, environmental pollution and high acid method cracking cost. A method of recovering silicone rubber comprising the steps of: 1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating and heating, mechanically crushing, spraying with an acid solvent, soaking in the acid solvent, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles; 2) Adding silicon rubber particles into a reaction kettle, adding a composite catalyst and a solvent, refluxing and stirring for reaction to obtain a mixed solution; 3) And (3) after rotary evaporation of the mixed solution, separating a gas phase and a liquid phase, adding an extractant into the liquid phase for ultrasonic extraction, centrifuging, taking supernatant, and drying in an oven to obtain DMC. Belongs to the technical field of DMC recovery of waste silicone rubber.
Description
Technical Field
The invention belongs to the technical field of recycling DMC (methyl methacrylate) from waste silicone rubber, and relates to a method and a device for recycling silicone rubber.
Background
The amount of waste and used silicone rubber produced in the production of silicone rubber, silicone rubber waste and scrap formed in the vulcanization molding process, and waste and used silicone rubber products formed in the application process have rapidly increased in recent years. Waste silicone rubber products cannot be decomposed naturally, so that the landfill mode cannot decompose and treat the waste silicone rubber. The process for converting the waste silicon rubber into the white carbon black by the combustion mode has huge energy consumption. The price of the raw materials of the silicon rubber is higher, and the generation and accumulation of the waste silicon rubber not only occupies a large amount of factories and pollutes the environment, but also causes the rise of cost, thereby causing great economic pressure to enterprises. Therefore, the recycling of the waste silicone rubber has great significance for reducing environmental pollution and improving economic benefit. At present, the recycling of the silicon rubber mainly comprises a physical crushing method and a chemical cracking method.
The chemical cracking method mainly comprises a base catalytic cracking method, an acid catalytic cracking method, a hydrolysis method, a thermal cracking method, an ultrasonic cracking method and the like. At present, the acid process cracking process is mainly adopted in China, because the inorganic matter content of the silicon rubber is higher, when the inorganic matter components are mainly alkaline matters such as aluminum oxide, aluminum hydroxide, iron oxide, carbonate and the like, acid serving as a catalyst can react with the alkaline matters, so that a large amount of catalyst is consumed, a large amount of side reaction residues are generated, the catalytic efficiency is influenced, waste acid is not easy to treat, secondary pollution is caused, the acid process cracking cost is high, and the traditional acid process cracking process has a certain limitation.
Disclosure of Invention
The invention aims to provide a method and a device for recycling silicon rubber, which remove alkaline inorganic metal salt by leaching metal ions, effectively reduce the usage amount of an acidic catalyst in the later period, and solve the problems of large usage amount of waste acid, environmental pollution and high acid method cracking cost; the compound catalyst adopts the combination of the p-toluenesulfonic acid and the dodecylbenzenesulfonic acid, and adopts the methanol as the solvent, and the three components are synergistic, so that compared with the single catalyst component, the yield of DMC is effectively improved.
The aim of the invention can be achieved by the following technical scheme:
a method of recycling silicone rubber, the method comprising the steps of:
1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating and heating, mechanically crushing, spraying with an acid solvent, soaking in the acid solvent, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles;
2) Adding silicon rubber particles into a reaction kettle, adding a composite catalyst and a solvent, refluxing and stirring for reaction to obtain a mixed solution;
3) And (3) after rotary evaporation of the mixed solution, separating a gas phase and a liquid phase, adding an extractant into the liquid phase for ultrasonic extraction, centrifuging, taking supernatant, and drying in an oven to obtain DMC.
As a preferred embodiment of the present invention, in step 1), the concentration of the acidic solvent is 50 to 60wt%; the soaking time is 3-4h, and the soaking temperature is 160-180 ℃; the acidic solvent is one of ammonium bisulfate or ammonium sulfate; the particle size of the silicone rubber particles is 0.2-0.9mm.
As a preferable technical scheme of the invention, in the step 1), the heating temperature rise comprises a first heating stage and a second heating stage, wherein the temperature of the first heating stage is 200-250 ℃, the time of the first heating stage is 0.5-1h, and the temperature of the second heating stage is 160-180 ℃.
As a preferred embodiment of the present invention, after the first heating stage step, a step of discharging exhaust gas is further included, and the exhaust gas is carbon dioxide.
As a preferable technical scheme of the invention, in the step 2), the composite catalyst is p-toluenesulfonic acid and dodecylbenzenesulfonic acid, wherein the mass ratio of p-toluenesulfonic acid to dodecylbenzenesulfonic acid is 1:0.5-1; the solvent is methanol.
As a preferred embodiment of the present invention, in step 2), the ratio of the amounts of the silicone rubber particles, the composite catalyst and the solvent is 25g:4g:150mL; the reflux temperature is 60-80 ℃, the stirring speed is 280-300r/min, and the reaction time is 3-4h.
As a preferable technical scheme of the invention, in the step 2), the composite catalyst is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the solvent is added in two times at intervals of 2 hours, and the addition amount of each time is 50% of the total amount of the solvent.
In step 3), the gas phase is the gas phase of the solvent in step 2), the extractant is n-hexane, and the mass ratio of the liquid phase to the extractant is 1:1, a step of; the ultrasonic extraction time is 10-15min, the centrifugation time is 5-8min, and the rotation speed of the centrifuge is 8000r/min; the drying time is 1-2h.
Further, the scheme of the invention also discloses a device for recycling the silicon rubber, which comprises an ultrasonic cleaner, a pulverizer, a high-speed refrigerated centrifuge, a reaction kettle, a magnetic stirrer and an electric heating constant-temperature drying oven.
The invention has the beneficial effects that:
1. the inorganic metal salt begins to thermally decompose at the temperature of the first heating stage, water or carbon dioxide is separated out, and the inorganic metal salt is soaked in an acid solvent, so that the leaching effect of metal ions is good in the temperature range of the second heating stage, and when the leaching temperature is too high, the metal ions such as Al in the leaching solution 3+ And Fe (Fe) 3+ Is easy to hydrolyze to generate sediment; the alkaline inorganic metal salt is removed by leaching metal ions, so that the use amount of the acid catalyst in the later period is effectively reduced, and the problems of large use amount of waste acid, environmental pollution and high acid method cracking cost are solved.
2. The mechanical crushing adopts acid solvent spraying simultaneously, and the acid solvent can destroy the structure of inorganic metal salt in the system, thereby providing crushing efficiency, and simultaneously, carrying out preliminary leaching on the inorganic metal salt, so that leaching and crushing are carried out simultaneously, and the effect of reducing the process time is achieved by combining part of working procedures.
3. The compound catalyst adopts the combination of the p-toluenesulfonic acid and the dodecylbenzenesulfonic acid, and adopts the methanol as the solvent, and the three components are synergistic, compared with the single catalyst component, the invention can effectively improve the yield of DMC.
4. Because of the acid-catalyzed rearrangement mechanism of the silicone rubber, the composite catalyst and the solvent are added in a staged manner, so that excessive catalyst consumption during initial reaction is avoided, and the siloxane tends to undergo polymerization.
Detailed Description
In order to further describe the technical means and effects adopted by the present invention for achieving the intended purpose, the following detailed description is given below with reference to the embodiments, structures, features and effects according to the present invention.
In the scheme of the invention, the device for the method for recycling the silicone rubber comprises an ultrasonic cleaner, a pulverizer, a high-speed refrigerated centrifuge, a reaction kettle, a magnetic stirrer and an electric heating constant-temperature drying oven.
Example 1
A method of recovering silicone rubber, the method comprising the steps of:
1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating the waste silicon rubber for 0.5h at the first stage of 200 ℃, discharging carbon dioxide gas, mechanically crushing at 160 ℃ in the second heating stage, spraying ammonium bisulfate, soaking for 3h at 160 ℃ after adding ammonium bisulfate, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.2mm; the concentration of the ammonium bisulfate is 50-60wt%;
2) Adding silicon rubber particles into a reaction kettle, adding p-toluenesulfonic acid, dodecylbenzenesulfonic acid and methanol, refluxing at 60 ℃, stirring at a rotating speed of 280r/min, and reacting for 3 hours to obtain a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:0.5; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles to the methanol is 25g:4g:150mL; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
3) Separating gas-phase methanol and liquid phase after rotary evaporation of the mixed solution, adding n-hexane into the liquid phase for ultrasonic extraction for 10min, centrifuging for 5min at the rotating speed of 8000r/min, taking supernatant, and drying in an oven for 1h to obtain DMC; wherein the mass ratio of the liquid phase to the normal hexane is 1:1.
example 2
A method of recovering silicone rubber, the method comprising the steps of:
1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating the waste silicon rubber for 0.7h at the first stage of 215 ℃, discharging carbon dioxide gas, mechanically crushing at 168 ℃ in the second heating stage, spraying by adopting ammonium bisulfate, soaking for 3.3h at 168 ℃ after adding the ammonium bisulfate, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.4mm; the concentration of ammonium bisulfate is 53wt%;
2) Adding silicon rubber particles into a reaction kettle, adding p-toluenesulfonic acid, dodecylbenzenesulfonic acid and methanol, refluxing at 66 ℃, stirring at a rotating speed of 286r/min, and reacting for 3.3h to obtain a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:0.65; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles to the methanol is 25g:4g:150mL; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
3) Separating gas-phase methanol and liquid phase after rotary evaporation of the mixed solution, adding n-hexane into the liquid phase for ultrasonic extraction for 12min, centrifuging for 6min at the rotating speed of 8000r/min, taking supernatant, and drying in an oven for 1.3h to obtain DMC; wherein the mass ratio of the liquid phase to the normal hexane is 1:1.
example 3
A method of recovering silicone rubber, the method comprising the steps of:
1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating the waste silicon rubber for 0.9h at the first stage of 230 ℃, discharging carbon dioxide gas, mechanically crushing at the temperature of 175 ℃ in the second heating stage, spraying by adopting ammonium bisulfate, soaking for 3.6h at the temperature of 175 ℃ after adding the ammonium bisulfate, filtering the leaching solution to obtain leaching residues, and ball-milling and sieving the leaching residues after drying to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.6mm; the concentration of ammonium bisulfate is 56wt%;
2) Adding silicon rubber particles into a reaction kettle, adding p-toluenesulfonic acid, dodecylbenzenesulfonic acid and methanol, refluxing at 73 ℃, stirring at 292r/min, and reacting for 3.6h to obtain a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:0.8; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles to the methanol is 25g:4g:150mL; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
3) Separating gas-phase methanol and liquid phase after rotary evaporation of the mixed solution, adding n-hexane into the liquid phase for ultrasonic extraction for 14min, centrifuging for 7min at the rotating speed of 8000r/min, taking supernatant, and drying in an oven for 1.5h to obtain DMC; wherein the mass ratio of the liquid phase to the normal hexane is 1:1.
example 4
A method of recovering silicone rubber, the method comprising the steps of:
1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating the waste silicon rubber for 1h at the first stage of 250 ℃, discharging carbon dioxide gas, mechanically crushing the waste silicon rubber at the temperature of 180 ℃ in the second heating stage, spraying ammonium bisulfate, soaking the waste silicon rubber for 4h at the temperature of 180 ℃ after adding the ammonium bisulfate, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving the leaching residues to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.9mm; the concentration of ammonium bisulfate is 60wt%;
2) Adding silicon rubber particles into a reaction kettle, adding p-toluenesulfonic acid, dodecylbenzenesulfonic acid and methanol, refluxing at 80 ℃, stirring at a rotating speed of 300r/min, and reacting for 4 hours to obtain a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:1, a step of; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles to the methanol is 25g:4g:150mL; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
3) Separating gas-phase methanol and liquid phase after rotary evaporation of the mixed solution, adding n-hexane into the liquid phase for ultrasonic extraction for 15min, centrifuging for 8min at the rotating speed of 8000r/min, taking supernatant, and drying in an oven for 2h to obtain DMC; wherein the mass ratio of the liquid phase to the normal hexane is 1:1.
comparative example 1
Compared to example 4, the difference is that step 1): after cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating at 180 ℃, mechanically crushing while spraying by adopting ammonium bisulfate, adding the ammonium bisulfate, soaking for 4 hours at 180 ℃, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.9mm; the concentration of ammonium bisulfate is 60wt%;
the other components, the preparation steps and the parameters are consistent.
Comparative example 2
Compared to example 4, the difference is that step 1): after cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating at 250 ℃ for 1h, mechanically crushing, spraying by adopting ammonium bisulfate, adding ammonium bisulfate, soaking for 4h at 180 ℃, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.9mm; the concentration of ammonium bisulfate is 60wt%;
the other components, the preparation steps and the parameters are consistent.
Comparative example 3
Compared to example 4, the difference is that step 1): after cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating the waste silicon rubber for 1h at the first stage of 250 ℃, discharging carbon dioxide gas, mechanically crushing the waste silicon rubber at the temperature of 200 ℃ in the second heating stage, spraying by adopting ammonium bisulfate, soaking the waste silicon rubber for 4h at 180 ℃ after adding the ammonium bisulfate, filtering the leaching solution to obtain leaching residues, and ball-milling and sieving the leaching residues after drying to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.9mm; the concentration of ammonium bisulfate is 60wt%;
the other components, the preparation steps and the parameters are consistent.
Comparative example 4
Compared to example 4, the difference is that step 1): after cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating the waste silicon rubber for 1h at the first stage of 250 ℃, discharging carbon dioxide gas, mechanically crushing the waste silicon rubber at the temperature of 180 ℃ in the second heating stage, spraying by adopting ammonium bisulfate, soaking the waste silicon rubber for 4h at the temperature of 200 ℃ after adding the ammonium bisulfate, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving the leaching residues to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.9mm; the concentration of ammonium bisulfate is 60wt%;
the other components, the preparation steps and the parameters are consistent.
Comparative example 5
Compared to example 4, the difference is that step 1): after cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating for 1h at the first stage of 250 ℃, discharging carbon dioxide gas, mechanically crushing at the temperature of 180 ℃ in the second heating stage, and ball-milling and sieving after drying to obtain silicon rubber particles; wherein, the grain diameter of the silicon rubber particles is 0.9mm; the concentration of ammonium bisulfate is 60wt%;
the other components, the preparation steps and the parameters are consistent.
Comparative example 6
Compared to example 4, the difference is that step 2): adding silicon rubber particles into a reaction kettle, adding p-toluenesulfonic acid, dodecylbenzenesulfonic acid and water, refluxing at 80 ℃, stirring at a rotating speed of 300r/min, and reacting for 4 hours to obtain a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:1, a step of; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles, the composite catalyst and the water is 25g:4g:150mL; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the water is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of water;
the other components, the preparation steps and the parameters are consistent.
Comparative example 7
Compared to example 4, the difference is that step 2): adding silicon rubber particles into a reaction kettle, adding dodecylbenzene sulfonic acid and methanol, refluxing at 80 ℃, stirring at the rotating speed of 300r/min, and reacting for 4 hours to obtain a mixed solution; the ratio of the amounts of the silicone rubber particles, the dodecylbenzenesulfonic acid and the methanol was 25g:4g:150mL; the dodecylbenzene sulfonic acid is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total dodecylbenzene sulfonic acid; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
the other components, the preparation steps and the parameters are consistent.
Comparative example 8
Compared to example 4, the difference is that step 2): adding silicon rubber particles into a reaction kettle, adding p-toluenesulfonic acid and methanol, refluxing at 80 ℃, stirring at the rotating speed of 300r/min, and reacting for 4 hours to obtain a mixed solution; the ratio of the amounts of the silicone rubber particles, the p-toluenesulfonic acid and the methanol was 25g:4g:150mL; the p-toluenesulfonic acid is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the p-toluenesulfonic acid; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
the other components, the preparation steps and the parameters are consistent.
Comparative example 9
Compared with the example 4, the method is characterized in that in the step 2), silicon rubber particles are added into a reaction kettle, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and methanol are added, reflux is carried out at 80 ℃, stirring is carried out at the rotating speed of 300r/min, and the reaction is carried out for 4 hours, thus obtaining a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:1, a step of; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles to the methanol is 25g:4g:150mL; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the methanol is added at one time;
the other components, the preparation steps and the parameters are consistent.
Comparative example 10
Compared with the example 4, the method is characterized in that in the step 2), silicon rubber particles are added into a reaction kettle, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and methanol are added, reflux is carried out at 80 ℃, stirring is carried out at the rotating speed of 300r/min, and the reaction is carried out for 4 hours, thus obtaining a mixed solution; wherein, the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:1, a step of; the composite catalyst comprises p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the ratio of the silicon rubber particles to the methanol is 25g:4g:150mL; the composite catalyst is added at one time; the methanol is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the methanol;
the other components, the preparation steps and the parameters are consistent.
Yield statistics were performed on DMC prepared in examples 1-4 and comparative examples 1-9, and the statistical results are shown in Table 1 below.
TABLE 1 statistical yields of DMC
| DMC yield/% | |
| Example 1 | 92 |
| Example 2 | 93 |
| Example 3 | 95 |
| Example 4 | 91 |
| Comparative example 1 | 71 |
| Comparative example 2 | 66 |
| Comparative example 3 | 58 |
| Comparative example 4 | 42 |
| Comparative example 5 | 63 |
| Comparative example 6 | 84 |
| Comparative example 7 | 55 |
| Comparative example 8 | 64 |
| Comparative example 9 | 78 |
| Comparative example 10 | 83 |
As is clear from the statistical results in Table 1, examples 1 to 4 and comparative examples 1 to 4, according to the present invention, inorganic metal salts are thermally decomposed by the temperature of the first heating stage, and the leaching effect of metal ions is good in the temperature range of the second heating stage in combination with the soaking in the acidic solvent, so that the amount of the acidic catalyst used in the late stage can be effectively reduced, but if the leaching temperature is too high, metal ions such as Al in the leaching solution 3+ And Fe (Fe) 3+ The hydrolysis is easy to generate precipitate, which affects the catalytic activity of the composite catalyst and the yield of DMC.
As can be seen from comparison of examples 1 to 4 with comparative example 5, the solution of the present invention provides crushing efficiency by mechanical crushing while spraying with an acidic solvent, and at the same time, performs primary leaching of inorganic metal salt, so that leaching and crushing are performed simultaneously, and by combining part of the procedures, the effect of reducing the process time is achieved, and the amount of use of the composite catalyst is reduced by means of soaking with an acidic solvent, which is advantageous for improving the yield of DMC.
As can be seen from comparison of examples 1-4 with comparative examples 6-8, the solution of the invention adopts the complex catalyst to compound p-toluenesulfonic acid and dodecylbenzenesulfonic acid and adopts methanol as solvent, and the three components synergistically increase the yield of DMC, compared with the single catalyst component, the solution of the invention can effectively improve the yield of DMC and solve the problem of low DMC yield caused by the traditional weak acid catalyst.
As can be seen from the comparison of examples 1-4 with comparative examples 9-10, when the amount of the composite catalyst is excessive or the amount of methanol is excessive, the polymerization of the siloxane during the initial reaction can be effectively avoided by adopting the method of adding the composite catalyst and the solvent in a sectional manner due to the acid-catalyzed rearrangement mechanism of the silicone rubber.
The present invention is not limited to the above embodiments, but is capable of modification and variation in detail, and other modifications and variations can be made by those skilled in the art without departing from the scope of the present invention.
Claims (4)
1. A method of recycling silicone rubber, the method comprising the steps of:
1) After cleaning and drying the waste silicon rubber, adding the waste silicon rubber into a pulverizer, heating and heating, mechanically crushing, spraying with an acid solvent, soaking in the acid solvent, filtering the leaching solution to obtain leaching residues, drying the leaching residues, and ball-milling and sieving to obtain silicon rubber particles; wherein the concentration of the acid solvent is 50-60wt%; the soaking time is 3-4h, and the soaking temperature is 160-180 ℃; the acidic solvent is one of ammonium bisulfate or ammonium sulfate; the particle size of the silicon rubber particles is 0.2-0.9mm; the heating temperature rise comprises a first heating stage and a second heating stage, wherein the temperature of the first heating stage is 200-250 ℃, the time of the first heating stage is 0.5-1h, and the temperature of the second heating stage is 160-180 ℃;
2) Adding silicon rubber particles into a reaction kettle, adding a composite catalyst and a solvent, refluxing and stirring for reaction to obtain a mixed solution; wherein the composite catalyst is p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and the mass ratio of the p-toluenesulfonic acid to the dodecylbenzenesulfonic acid is 1:0.5-1; the solvent is methanol; the composite catalyst is added for two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the composite catalyst; the solvent is added in two times, the time interval is 2 hours, and the addition amount of each time is 50% of the total amount of the solvent;
3) And (3) after rotary evaporation of the mixed solution, separating a gas phase and a liquid phase, adding an extractant into the liquid phase for ultrasonic extraction, centrifuging, taking supernatant, and drying in an oven to obtain DMC.
2. A method of recycling silicone rubber according to claim 1, characterized in that: the first heating stage step is followed by a step of discharging exhaust gas, wherein the exhaust gas is carbon dioxide.
3. A method of recycling silicone rubber according to claim 1, characterized in that: in step 2), the ratio of the amounts of silicone rubber particles, composite catalyst and solvent used is 25g:4g:150mL; the reflux temperature is 60-80 ℃, the stirring speed is 280-300r/min, and the reaction time is 3-4h.
4. A method of recycling silicone rubber according to claim 1, characterized in that: in the step 3), the gas phase is the gas phase of the solvent in the step 2), the extractant is n-hexane, and the mass ratio of the liquid phase to the extractant is 1:1, a step of; the ultrasonic extraction time is 10-15min, the centrifugation time is 5-8min, and the rotation speed of the centrifuge is 8000r/min; the drying time is 1-2h.
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| JP2005307119A (en) * | 2004-04-26 | 2005-11-04 | Shinko Giken Kk | Method for regenerating silicone oil/silicone grease from used silicone rubber |
| KR100902888B1 (en) * | 2008-03-07 | 2009-06-16 | 윤대식 | Method on silicon compound recovery from silicon waste |
| CN113563376A (en) * | 2021-07-08 | 2021-10-29 | 枣阳市一鸣化工有限公司 | Method for recovering waste silicon rubber |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005307119A (en) * | 2004-04-26 | 2005-11-04 | Shinko Giken Kk | Method for regenerating silicone oil/silicone grease from used silicone rubber |
| KR100902888B1 (en) * | 2008-03-07 | 2009-06-16 | 윤대식 | Method on silicon compound recovery from silicon waste |
| CN113563376A (en) * | 2021-07-08 | 2021-10-29 | 枣阳市一鸣化工有限公司 | Method for recovering waste silicon rubber |
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| Title |
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| 硅橡胶回收利用技术的研究进展;杨金云 等;有机硅材料;409-415 * |
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