CN116355008A - Treatment process for recycling silicone rubber - Google Patents
Treatment process for recycling silicone rubber Download PDFInfo
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- CN116355008A CN116355008A CN202310360417.8A CN202310360417A CN116355008A CN 116355008 A CN116355008 A CN 116355008A CN 202310360417 A CN202310360417 A CN 202310360417A CN 116355008 A CN116355008 A CN 116355008A
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- silicone rubber
- reaction kettle
- diethylamine
- recycling
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- 229920002379 silicone rubber Polymers 0.000 title claims abstract description 78
- 239000004945 silicone rubber Substances 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 52
- 230000008569 process Effects 0.000 title claims abstract description 41
- 238000004064 recycling Methods 0.000 title claims abstract description 25
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims abstract description 90
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 claims abstract description 72
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 60
- GLDOVTGHNKAZLK-UHFFFAOYSA-N octadecan-1-ol Chemical compound CCCCCCCCCCCCCCCCCCO GLDOVTGHNKAZLK-UHFFFAOYSA-N 0.000 claims abstract description 54
- HPNMFZURTQLUMO-UHFFFAOYSA-N diethylamine Chemical compound CCNCC HPNMFZURTQLUMO-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000002699 waste material Substances 0.000 claims abstract description 32
- -1 siloxane chain Chemical group 0.000 claims abstract description 30
- 239000000945 filler Substances 0.000 claims abstract description 29
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims abstract description 26
- 235000019796 monopotassium phosphate Nutrition 0.000 claims abstract description 26
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000006243 chemical reaction Methods 0.000 claims description 100
- 238000010438 heat treatment Methods 0.000 claims description 33
- 239000000843 powder Substances 0.000 claims description 27
- 239000007787 solid Substances 0.000 claims description 24
- 239000000725 suspension Substances 0.000 claims description 20
- 238000001035 drying Methods 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 13
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 12
- 239000008055 phosphate buffer solution Substances 0.000 claims description 11
- 230000035484 reaction time Effects 0.000 claims description 2
- 239000003054 catalyst Substances 0.000 abstract description 12
- 238000005336 cracking Methods 0.000 abstract description 11
- 239000002904 solvent Substances 0.000 abstract description 11
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 239000004205 dimethyl polysiloxane Substances 0.000 abstract description 5
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 4
- 239000007853 buffer solution Substances 0.000 abstract description 3
- 238000003763 carbonization Methods 0.000 abstract description 3
- 239000003795 chemical substances by application Substances 0.000 abstract description 3
- 238000011084 recovery Methods 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 239000000413 hydrolysate Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 5
- 239000011259 mixed solution Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000007792 addition Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 238000000053 physical method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- GETQZCLCWQTVFV-UHFFFAOYSA-N trimethylamine Chemical compound CN(C)C GETQZCLCWQTVFV-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 108010009736 Protein Hydrolysates Proteins 0.000 description 1
- 229910018557 Si O Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000010170 biological method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 238000004523 catalytic cracking Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229920006037 cross link polymer Polymers 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 238000007323 disproportionation reaction Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 239000005055 methyl trichlorosilane Substances 0.000 description 1
- JLUFWMXJHAVVNN-UHFFFAOYSA-N methyltrichlorosilane Chemical compound C[Si](Cl)(Cl)Cl JLUFWMXJHAVVNN-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- HMMGMWAXVFQUOA-UHFFFAOYSA-N octamethylcyclotetrasiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 HMMGMWAXVFQUOA-UHFFFAOYSA-N 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000008363 phosphate buffer Substances 0.000 description 1
- IALUUOKJPBOFJL-UHFFFAOYSA-N potassium oxidosilane Chemical compound [K+].[SiH3][O-] IALUUOKJPBOFJL-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
- 238000003911 water pollution Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/21—Cyclic compounds having at least one ring containing silicon, but no carbon in the ring
-
- 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
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The invention relates to a treatment process for recycling silicon rubber, and belongs to the technical field of silicon rubber. The invention provides a treatment process for recycling silicon rubber, which realizes effective recycling of waste silicon rubber by a cracking process taking methanol, diethylamine and hexane as filler recycling agents, tetramethylammonium hydroxide as a catalyst and n-octadecanol as a solvent and a filler recycling method; the invention uses the solvent cracking process to treat the waste silicone rubber, reduces the carbonization probability of the siloxane chain units, and is beneficial to improving the generation rate of cyclosiloxane to a certain extent; the invention uses the tetramethyl ammonium hydroxide as the catalyst, and the tetramethyl ammonium hydroxide as the catalyst overcomes the problem that KOH catalyst remains in dimethyl siloxane so as to not meet the production requirement of high-quality silicon rubber, improves the yield of the ring body, and effectively separates the filler; after the polydimethylsiloxane is cracked to reach an equilibrium stage, buffer solution potassium dihydrogen phosphate is added to promote the polydimethylsiloxane to form a ring structure.
Description
Technical Field
The invention belongs to the technical field of silicone rubber, and particularly relates to a treatment process for recycling silicone rubber.
Background
With the development of industrial production, transportation, urban construction and the increase of population density, problems of noise pollution, atmospheric pollution, water pollution and solid waste discharge are increasingly serious, and the problems are listed as four pollution in the world. The silicone rubber is a synthetic rubber with a silicon-oxygen bond as a main chain, has the performances of high and low temperature resistance, radiation resistance, high pressure resistance, physiological inertia, ozone aging resistance, weather resistance, high air permeability and the like, and shows excellent chemical inertia to mediums such as solvent oil, lubricating oil and the like. The yield and consumption of the silicone rubber are rapidly increased in recent years, the consumption of the heat vulcanized silicone rubber in China in 2013 reaches 328kt, and the average increase of the consumption is 7% -8% per year. With this, the amount of scrap raw silicone rubber produced in production, silicone rubber waste and scrap formed in vulcanization molding processing, and waste silicone rubber products formed in application has been rapidly increased. Estimated according to the reject rate of 10% per year, the amount of the produced waste silicone rubber products exceeds 30kt, which is a problem that cannot be ignored. The organic silicon compound 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 main methods for recycling the waste silicone rubber include a physical method, a chemical method, a biological method and the like. Wherein the physical method mainly comprises crushing, crushing and hot pressing, and the waste silicone rubber is converted into reusable powder or particles. However, the method can not change the molecular structure and the property of the waste silicone rubber, can only be used as a filler or an inferior raw material, is not suitable for the gradual oxidation of the silicone rubber after multiple uses, and can cause energy consumption and equipment loss. The chemical method mainly comprises a solvent method, a catalytic cracking method and the like, and the waste silicone rubber is decomposed into organic silicon monomers or other low molecular weight substances.
In addition, some disproportionation side reactions also occur in the reaction to produce crosslinked polymers, which also affect the production of cyclodimethylsiloxane to some extent. The methyltrichlorosilane readily forms trifunctional groups during the hydrolysis step. The hydrolysate is excessively crosslinked and generates a large amount of silicon hydroxyl groups, the hydroxyl groups are hydrophilic, the molecular framework is hydrophobic, so that hydrolytic cementation is caused, the viscosity of the hydrolysate is increased, the separation difficulty of chloride ions in the hydrolysate is increased, and even the hydrolysate adheres to hydrolysis equipment. Meanwhile, when the trifunctional hydrolysate is carried to cracking, the materials are easy to bond, the forced drying is difficult and the wet slag quantity is large during single kettle intermittent cracking, so that the content of octamethyl cyclotetrasiloxane (D4) in dimethyl cyclosiloxane (DMC) is easy to reduce; and the high-viscosity hydrolysate can cause high content of acid value, end group chlorine, trifunctional connection and other impurities in the hydrolysate, and the production requirements of high-quality silicon rubber can not be met.
Disclosure of Invention
The invention provides a treatment process for recycling silicon rubber, which realizes effective recycling of waste silicon rubber by a cracking process taking methanol, diethylamine and hexane as filler recycling agents, tetramethylammonium hydroxide as a catalyst and n-octadecanol as a solvent and a filler recycling method; the invention uses the solvent cracking process to treat the waste silicone rubber, reduces the carbonization probability of the siloxane chain units, and is beneficial to improving the generation rate of cyclosiloxane to a certain extent; the invention uses the tetramethyl ammonium hydroxide as the catalyst, and the tetramethyl ammonium hydroxide as the catalyst overcomes the problem that KOH catalyst remains in dimethyl siloxane so as to not meet the production requirement of high-quality silicon rubber, improves the yield of the ring body, and effectively separates the filler; after the polydimethylsiloxane is cracked to reach an equilibrium stage, buffer solution potassium dihydrogen phosphate is added to promote the polydimethylsiloxane to form a ring structure.
The aim of the invention can be achieved by the following technical scheme:
a process for the treatment of reclaimed silicone rubber comprising the steps of:
step one: crushing waste silicone rubber into powder, and placing the powder into a reaction kettle;
step two: adding methanol, diethylamine, hexane and tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, and heating for reaction;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, continuing to perform heating reaction, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: the solid recovered in step three was treated with a mixture of diethylamine and hexane to give a filler.
As a preferable scheme of the invention, the dosage ratio of the silicone rubber powder, the methanol, the diethylamine and the tetramethylammonium hydroxide in the second step is 5g to 3mL to 5mL to 2.5 to 10mL to 0.4 to 0.6g.
As a preferable scheme of the invention, the volume ratio of the addition amount of the hexane to the diethylamine in the step four is 1:1.
As a preferable scheme of the invention, the ratio of the added volume of the n-octadecanol to the volume of the reaction kettle in the fourth step is 1:20-25.
As a preferable scheme of the invention, the temperature of the reaction kettle after the temperature is raised in the step four is controlled to be 120-130 ℃, and the pressure of the reaction kettle is controlled to be 5-10kPa.
As a preferred scheme of the invention, the molar ratio of the potassium dihydrogen phosphate in the step five to the tetramethylammonium hydroxide in the step two is 0.8-1:1.
As a preferable scheme of the invention, the temperature after the temperature rise in the step five is 180 ℃.
As a preferable scheme of the invention, the reaction time in the step five is 90-120min.
The invention has the beneficial effects that:
1. the invention provides a treatment process for recycling silicon rubber, which realizes effective recycling of waste silicon rubber by using a cracking process with methanol, diethylamine and hexane as filler recycling agents, tetramethyl ammonium hydroxide as a catalyst and n-stearyl alcohol as a solvent and a filler recycling method, and the recycled dimethyl siloxane has high ring content.
2. In the treatment process for recycling the silicone rubber, the solvent cracking process is used for treating the waste silicone rubber. The solvent is n-octadecanol, is an inert substance, has the advantages of high boiling point, low viscosity, strong heat transfer capability and the like, can effectively reduce the viscosity of a reaction system in a cracking kettle, ensures that the heat transfer of the system is more uniform, eliminates the local overheating phenomenon, reduces the cracking side reaction and reduces the generation of C, H by cracking carbon-silicon bonds and hydrocarbon bonds in siloxane chain links 2 The occurrence of the reaction reduces the carbonization probability of the siloxane chain units, and is beneficial to improving the generation rate of cyclosiloxane to a certain extent.
3. In the treatment process for recycling the silicone rubber, tetramethylammonium hydroxide is used as a catalyst, and the tetramethylammonium hydroxide is stably present at a temperature not exceeding a decomposition point and rapidly decomposed into trimethylamine and methanol when exceeding the decomposition point. Is easy to remove after the catalysis is finished, and does not leave any residue. No contamination of the organosilicon product and is therefore also referred to as a "temporary catalyst". The tetramethyl ammonium hydroxide is used as a catalyst to solve the problem that the traditional strong base KOH catalysis is remained in the dimethyl siloxane, so that the production requirement of high-quality silicon rubber cannot be met.
4. The diethylamine and methanol in the present invention can effectively swell the silicone rubber, so that the filler is separated from the polydimethylsiloxane chain, and the mixture of diethylamine, methanol and hexane not only very effectively promotes the depolymerization of the silica-and alumina-containing silicone rubber, but also completely separates the filler by filtration before removing the monomers and solvents. After removal of the solvent, a higher content of cyclosiloxanes can be obtained in the distillation. Meanwhile, the tetramethylammonium hydroxide is adopted to replace KOH, so that the cyclosiloxane yield is improved, and the filler is effectively separated.
5. After the polydimethylsiloxane is cracked to reach an equilibrium stage, buffer solution potassium dihydrogen phosphate is gradually added to neutralize excessive disilyloxide and convert the disilyloxide into monosilicon alkoxide, so that the quantity of smaller potassium silanolate consisting of one or two Si-O units is reduced, and the formation of a ring structure is promoted.
6. According to the invention, the filler of the waste silicone rubber is effectively recycled in the process, so that the recycling treatment of waste materials is realized, the waste of resources is avoided, and the method is environment-friendly.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
A process for the treatment of reclaimed silicone rubber comprising the steps of:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3L of methanol, 2.5L of diethylamine, 2.5L of hexane and 0.4kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:20, heating to 120 ℃ for reaction, and controlling the pressure of the reaction kettle to be 5kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 90min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.8:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
Example 2
A process for the treatment of reclaimed silicone rubber comprising the steps of:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3.5L of methanol, 4.5L of diethylamine, 4.5L of hexane and 0.45kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a mixed solution;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:21, heating to 122 ℃ for reaction, and controlling the pressure of the reaction kettle to be 6kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 97min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.85:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
Example 3
A process for the treatment of reclaimed silicone rubber comprising the steps of:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 4L of methanol, 6.8L of diethylamine, 6.8L of hexane and 0.5kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:23, heating to 125 ℃ for reaction, and controlling the pressure of the reaction kettle to be 7kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 105min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.9:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
Example 4
A process for the treatment of reclaimed silicone rubber comprising the steps of:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3L of methanol, 2.5L of diethylamine, 2.5L of hexane and 0.4kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a mixed solution;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:24, heating to 127 ℃ for reaction, and controlling the pressure of the reaction kettle to be 8kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 112min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.95:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
Example 5
A process for the treatment of reclaimed silicone rubber comprising the steps of:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3L of methanol, 2.5L of diethylamine, 2.5L of hexane and 0.4kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:25, heating to 130 ℃ for reaction, and controlling the pressure of the reaction kettle to be 10kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 120min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 1:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
Comparative example 1
In comparison with example 1, the treatment process for recycling silicone rubber, without adding ethylenediamine, comprises the following steps:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3L of methanol, 2.5L of hexane and 0.4kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:20, heating to 120 ℃ for reaction, and controlling the pressure of the reaction kettle to be 5kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 90min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.8:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
The rest of the procedure is the same as in example 1.
Comparative example 2
In comparison with example 2, the treatment process for recovering silicone rubber, without adding hexane, comprises the following steps:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3.5L of methanol, 4.5L of diethylamine and 0.45kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a mixed solution;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:21, heating to 122 ℃ for reaction, and controlling the pressure of the reaction kettle to be 6kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 97min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.85:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
The remaining steps were the same as in example 2.
Comparative example 3
In comparison with example 3, the treatment process for recycling silicone rubber, without adding diethylamine and hexane, comprises the following steps:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 4L of methanol and 0.5kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:23, heating to 125 ℃ for reaction, and controlling the pressure of the reaction kettle to be 7kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 105min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 0.9:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
The remaining steps were the same as in example 3.
Comparative example 4
In comparison with example 4, the treatment process for recycling silicone rubber, without adding potassium dihydrogen phosphate buffer, comprises the following operation steps:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3L of methanol, 2.5L of diethylamine, 2.5L of hexane and 0.4kg of tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a mixed solution;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:24, heating to 127 ℃ for reaction, and controlling the pressure of the reaction kettle to be 8kPa;
step five: then heating the reaction kettle for 112min, controlling the temperature to be 180 ℃, collecting condensate, and drying the condensate by using anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
The remaining steps were the same as in example 4.
Comparative example 5
A process for the recovery of silicone rubber, in comparison with example 5, using KOH instead of tetramethylammonium hydroxide, comprising the following operative steps:
step one: crushing 5kg of waste silicone rubber into powder, and putting the powder into a reaction kettle;
step two: adding 3L of methanol, 2.5L of diethylamine, 2.5L of hexane and 0.4kg of KOH into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, wherein the volume ratio of the n-octadecanol to the reaction kettle is 1:25, heating to 130 ℃ for reaction, and controlling the pressure of the reaction kettle to be 10kPa;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, heating for reaction for 120min, controlling the molar ratio of potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step to be 1:1, controlling the temperature after heating to be 180 ℃, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: and (3) treating the solid recovered in the step (III) with a mixture of diethylamine and hexane to obtain the filler.
The remaining steps were the same as in example 5.
The recovery of the filler and the recovery of dimethylcyclosiloxane in examples 1-5 and comparative examples 1-5 are shown in Table 1.
TABLE 1
As can be seen from Table 1, the treatment process for reclaimed silicone rubber provided in examples 1 to 5 had good recovery rate of filler and recovery rate of dimethylsiloxane, and the treatment process for reclaimed silicone rubber provided in comparative examples 1 to 4 had different degrees of decrease in recovery rate of filler and recovery rate of dimethylsiloxane, and the treatment process for reclaimed silicone rubber provided in examples 1 to 5 and the treatment process for reclaimed silicone rubber provided in comparative example 5 gave comparable results in recovery rate of filler and recovery rate of dimethylsiloxane.
In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing is merely illustrative and explanatory of the invention, as various modifications and additions may be made to the particular embodiments described, or in a similar manner, by those skilled in the art, without departing from the scope of the invention or exceeding the scope of the invention as defined in the claims.
Claims (8)
1. A treatment process for recycling silicon rubber is characterized by comprising the following steps: the treatment process comprises the following steps:
step one: crushing waste silicone rubber into powder, and placing the powder into a reaction kettle;
step two: adding methanol, diethylamine, hexane and tetramethylammonium hydroxide into a reaction kettle, and stirring at room temperature to obtain a suspension;
step three: filtering the suspension to separate out solid;
step four: adding n-octadecanol into a reaction kettle, and heating for reaction;
step five: adding potassium dihydrogen phosphate buffer solution into a reaction kettle, continuing to perform heating reaction, collecting condensate, and drying with anhydrous sodium sulfate to obtain dimethyl siloxane;
step six: the solid recovered in step three was treated with a mixture of diethylamine and hexane to give a filler.
2. The process for treating recycled silicone rubber according to claim 1, wherein: in the second step, the dosage ratio of the silicon rubber powder, the methanol, the diethylamine and the tetramethylammonium hydroxide is 5g to 3mL-5mL to 2.5-10mL to 0.4-0.6g.
3. The process for treating recycled silicone rubber according to claim 1, wherein: and in the second step, the volume ratio of the addition amount of the hexane to the diethylamine is 1:1.
4. The process for treating recycled silicone rubber according to claim 1, wherein: and in the fourth step, the ratio of the added volume of the n-octadecanol to the volume of the reaction kettle is 1:20-25.
5. The process for treating recycled silicone rubber according to claim 1, wherein: in the fourth step, the temperature of the reaction kettle after temperature rise is controlled to be 120-130 ℃, and the pressure of the reaction kettle is controlled to be 5-10kPa.
6. The process for treating recycled silicone rubber according to claim 1, wherein: and in the fifth step, the molar ratio of the potassium dihydrogen phosphate to the tetramethylammonium hydroxide in the second step is 0.8-1:1.
7. The process for treating recycled silicone rubber according to claim 1, wherein: and step five, the temperature after the temperature rise is 180 ℃.
8. The process for treating recycled silicone rubber according to claim 1, wherein: and step five, the reaction time is 90-120min.
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