Supported sulfur removal material combinations and methods of making, using, deep sulfur removal system and method for hydrogen-based polysiloxanes

Abstract

This disclosure presents a solid-supported desulfurization material assembly and its preparation method, application, and a deep desulfurization system and method for hydrogen-based polysiloxanes, belonging to the field of organosilicon material refining technology. The solid-supported desulfurization material assembly includes: an active sulfur-capturing material and an inert sulfur complexing material; the active sulfur-capturing material includes a first inner layer formed of porous particles, thiol capture acceptor groups located within the pores of the porous particles, and a first silicon phase compatibility layer encapsulated on the outer surface of the first inner layer; the inert sulfur complexing material includes a second inner layer formed of porous particles, an inert sulfur complexing metal located within the pores of the porous particles, and a second silicon phase compatibility layer encapsulated on the outer surface of the second inner layer. The desulfurization material of this disclosure is a core-shell structured porous particle, with an outer silicon phase compatibility layer and an inner active site layer, thereby achieving deep desulfurization while reducing viscosity drift and Si-H loss caused by the non-selective strong adsorption of resin.

Description

Technical Field

[0001] This disclosure belongs to the field of organosilicon material refining technology, specifically relating to a solid-supported desulfurization material combination and its preparation method, application, and a deep desulfurization system and method for hydrogen-based polysiloxanes. Background Technology

[0002] Hydrogen-based polysiloxanes (containing Si-H components) are widely used in platinum-catalyzed addition curing systems. Trace amounts of sulfur impurities introduced during production, storage, upstream synthesis, or by external additives can cause platinum catalysis inhibition or poisoning, manifesting as prolonged induction period, fluctuating curing rate, and unstable gel time. Sulfur impurities typically include reactive sulfur (such as thiols) and inert sulfur (such as thioethers, sulfides, and thiophenes). Traditional solid adsorption / treatment methods easily lead to non-selective strong adsorption of silane resins on solid surfaces, resulting in viscosity drift, loss of effective Si-H, and even the risk of residual particles and metal leaching. Furthermore, using only total sulfur as the endpoint criterion may be lagging and cannot directly reflect the sensitivity to addition curing.

[0003] Therefore, there is an urgent need for a solution that combines deep removal, low Si-H loss, and controllable endpoint for deep desulfurization and process control of silane-hydrogen resin. Summary of the Invention

[0004] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a combination of solid-load desulfurization materials and its preparation method, application, and a deep desulfurization system and method of hydrogen-based polysiloxane.

[0005] One aspect of this disclosure provides a fixed-load desulfurization material assembly, comprising: an active sulfur-capturing material and an inert sulfur-complexing material; wherein, The active sulfur capturing material is used to selectively and irreversibly capture sulfur-containing thiol impurities. It includes a first inner layer formed by porous particles, thiol capturing acceptor groups located in the pores of the porous particles, and a first silicon phase compatibility layer wrapped around the outer surface of the first inner layer. The inert sulfur complexing material is used for selective complexation and adsorption of sulfur-containing impurities such as sulfides, sulfides, and thiophenes. It includes a second inner layer formed by porous particles, an inert sulfur complexing metal located in the pores of the porous particles, and a second silicon phase compatibility layer wrapped around the outer surface of the second inner layer.

[0006] Optionally, the thiol capture acceptor group is selected from at least one of maleimide group, vinyl sulfone group, activated acrylate group and activated haloalkyl group.

[0007] Optionally, the inert sulfur complex metal comprises Cu(I) and / or Ag(I).

[0008] Optionally, both the first silicon phase compatibility layer and the second silicon phase compatibility layer are siloxane brush layers; wherein, The siloxane brush layer is a hydroxyl-terminated polydimethylsiloxane segment.

[0009] Optionally, the coverage of the siloxane brush layer is 30-100%, and the equivalent thickness is 0.5-200 nm; The grafting amount and grafting density of the siloxane brush layer satisfy at least one of the following: The organic layer mass fraction, calculated by thermogravimetric analysis, is 0.1-10 wt%. The grafting amount per unit external surface area is 0.01-5 mmol / m². 2 ; The chain density is 0.01-5 chains / nm. 2 .

[0010] Optionally, the porous particles are selected from at least one of molecular sieves, silicon-aluminum materials, porous silica, and porous alumina; The porous particles have an average particle size of 20-2000 μm, a pore size of 2-200 nm, and a specific surface area of ​​10-1000 m². 2 / g.

[0011] In another aspect of this disclosure, a method for preparing the aforementioned immobilized desulfurization material assembly is provided, the method comprising: Porous particles are provided, and a pore protection phase is formed inside the pores of the porous particles. The outer surface of the porous particles is subjected to silicon phase compatibility treatment to form a silicon phase compatibility layer. The protective phase of the pores is removed, and active sites are constructed on the inner surface of the porous particle pores to form a core-shell structured solid-supported desulfurization material with an outer surface compatibility and an active inner pore structure; wherein... The active site is a thiol capture acceptor group or an inert sulfur complex metal.

[0012] In another aspect of this disclosure, a deep desulfurization system for hydrogen-based polysiloxanes is proposed, the deep desulfurization system comprising: The dehydration / degassing unit is used for dehydration and degassing pretreatment of hydrogen-based polysiloxanes. An active sulfur chemical capture unit, comprising the active sulfur capture material described above, is used for the selective and irreversible capture of sulfur-containing mercaptan impurities in pretreated hydrogen-based polysiloxanes. An inert sulfur complex adsorption unit, comprising the inert sulfur complexing material described above, is used for selective complex adsorption of sulfur-containing impurities such as sulfides, sulfides, and thiophenes in the treated hydrogen-based polysiloxane. The filtration and analysis unit filters the processed hydrogen-based polysiloxane, takes samples for analysis, and obtains hydrogen-based polysiloxane with reduced total sulfur content while maintaining Si-H activity.

[0013] In another aspect of this disclosure, a deep desulfurization method for hydrogen-based polysiloxanes is proposed, the deep desulfurization method comprising: Pretreatment of hydrogen-based polysiloxanes by dehydration and degassing; The active sulfur-capturing material described above is used to selectively and irreversibly capture sulfur-containing thiol impurities in pretreated hydrogen-based polysiloxanes. The inert sulfur complexing material described above was used to selectively complex and adsorb sulfur-containing impurities such as sulfides, sulfides, and thiophenes in the treated hydrogen-based polysiloxane. The treated hydrogen-based polysiloxane was filtered and sampled for analysis to obtain hydrogen-based polysiloxane with a total sulfur content that met the requirements.

[0014] Another aspect of this disclosure proposes an application of a fixed desulfurization material combination, wherein the fixed desulfurization material combination described above is used in the refining of silicon hydrogen raw materials for addition-type silicone encapsulants, die bond adhesives, or LED encapsulation materials.

[0015] This disclosure presents a solid-supported desulfurization material combination and its preparation method, application, and a deep desulfurization system and method using hydrogen-based polysiloxanes. The solid-supported desulfurization material combination includes: an active sulfur-capturing material and an inert sulfur complexing material; wherein, the active sulfur-capturing material is used for selective irreversible capture of thiol-type sulfur-containing impurities, and includes a first inner layer formed of porous particles, thiol-capturing acceptor groups located within the pores of the porous particles, and a first silicon-phase compatibility layer encapsulated on the outer surface of the first inner layer; the inert sulfur complexing material is used for selective complexation and adsorption of sulfides, sulfides, and thiophenes-type sulfur-containing impurities, and includes a second inner layer formed of porous particles, an inert sulfur complexing metal located within the pores of the porous particles, and a second silicon-phase compatibility layer encapsulated on the outer surface of the second inner layer. The desulfurization material of this disclosure is a core-shell structured porous particle, with an outer silicon-phase compatibility layer and an inner active site layer, thereby achieving deep desulfurization while reducing viscosity drift and Si-H loss caused by non-selective strong adsorption of resin. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the fixed-load desulfurization material assembly according to a specific embodiment of this disclosure; Figure 2 This is a flowchart illustrating the preparation method of the solidified desulfurization material combination according to a specific embodiment of this disclosure; Figure 3 This is a schematic diagram of a desulfurization system according to a specific embodiment of the present disclosure; Figure 4 This is a schematic diagram of the sampling and analysis unit according to a specific embodiment of this disclosure; Figure 5 This is a flowchart illustrating the desulfurization method according to a specific embodiment of this disclosure. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0018] like Figure 1 As shown, one aspect of this disclosure proposes a fixed-load desulfurization material combination, comprising: an active sulfur capture material 110 and an inert sulfur complexing material 120; wherein, the active sulfur capture material is used for selective irreversible capture of thiol-type sulfur-containing impurities, and includes a first inner layer 111 formed of porous particles, thiol capture acceptor groups 112 located within the pores of the porous particles, and a first silicon phase compatibility layer 113 wrapped around the outer surface of the first inner layer 111; the inert sulfur complexing material 120 is used for selective complexation and adsorption of sulfides, sulfides, and thiophenes-type sulfur-containing impurities, and includes a second inner layer 121 formed of porous particles, an inert sulfur complexing metal 122 located within the pores of the porous particles, and a second silicon phase compatibility layer 123 wrapped around the outer surface of the second inner layer 121.

[0019] It should be noted that the solid-supported desulfurization material combination disclosed herein includes two components. One component selectively and irreversibly captures active sulfur compounds such as thiols by supporting thiol capture acceptor groups, and will not desorb or leak out after adsorption. The other component selectively complexes and adsorbs inert sulfur compounds such as sulfides, sulfides, and thiophenes by loading complexing active sites. This selective adsorption is achieved by metal coordination. Based on the synergistic use of the above two components, both active and inert sulfur can be deeply removed, reducing viscosity drift and Si-H loss caused by solid treatment.

[0020] It should be further noted that in this embodiment, by setting a silicon-phase compatibility layer on the outer surface of the porous particles and distributing the active sites mainly on the inner surface of the pores of the porous particles, a core-shell structure with an outer surface compatibility and an inner pore active structure is formed. The outer surface compatibility layer reduces the non-selective strong adsorption of resin on the outer surface of the particles, while the active sites within the pores selectively capture or complex sulfur. Of course, the active sites mentioned here refer to thiol capture acceptor groups or inert sulfur complexes with metals.

[0021] It should be noted that, under optimal conditions, all active sites are located inside the pores of porous particles. However, in actual operation, a certain proportion will be located outside the pores. The apparent density of active sites on the outer surface should be much lower than the number of active sites inside the pores. That is, generally speaking, the apparent density of active sites on the outer surface is ≤ 50% of the apparent density of active sites in the inner pores, preferably ≤ 20%.

[0022] In other preferred embodiments, the thiol capture acceptor group is selected from at least one of maleimide groups, vinyl sulfone groups, activated acrylate groups, and activated haloalkyl groups. These groups and the thiol's mercapto (-SH) group can undergo a highly efficient and irreversible chemical reaction under mild conditions, with extremely high selectivity, preferentially reacting with thiol impurities and exhibiting low side effects on the target organosilicon component.

[0023] In some other preferred embodiments, the inert sulfur complex metal comprises Cu(I) and / or Ag(I). These soft acid metal ions, according to the hard-soft acid-base theory, have a very strong coordination affinity for soft base inert sulfides such as thiophenes and thiophenes, and can specifically complex and adsorb these difficult-to-remove sulfides, while showing almost no adsorption for non-sulfur-containing hydrocarbons. Their selectivity is far higher than other metals, and their adsorption capacity is also higher.

[0024] In some other preferred embodiments, both the first silicon phase compatibility layer and the second silicon phase compatibility layer are silanized or siloxane brush layers. The formed silanized / siloxane brush layers are low surface energy, hydrophobic inert silicon-based shells that can shield the polar hydroxyl groups on the outer surface, greatly reducing the useless adsorption of resin chains or target organic components on the outer surface of the particles, that is, reducing the non-selective strong adsorption of resin on the outer surface of the particles.

[0025] As a further preferred option, the siloxane brush layer is a hydroxyl-terminated polydimethylsiloxane segment.

[0026] As a further preferred embodiment, the coverage of the siloxane brush layer is 30-100%, for example, 50-100%, and the equivalent thickness is 0.5-200nm, for example, 2-50nm.

[0027] In other preferred embodiments, the grafting amount and grafting density of the siloxane brush layer satisfy at least one of the following: (1) The mass fraction of the organic layer, calculated by thermogravimetric analysis, is 0.1-10 wt%; (2) The grafting amount per unit external surface area is 0.01-5 mmol / m 2 ; (3) The chain density is 0.01-5 chains / nm. 2The above grafting parameters avoid over-grafting. If the grafting amount is too high or the brush layer is too thick, it will lead to a decrease in the overall specific surface area of ​​the particles, or even block the pore inlet, affecting the utilization rate of internal functional sites.

[0028] In some other preferred embodiments, the porous particles are selected from at least one of molecular sieves, silicon-aluminum materials, porous silica, and porous alumina, and the porous particles serve as a carrier with corresponding functional sites loaded within the pores.

[0029] In other preferred embodiments, the porous particles have an average particle size of 20-2000 μm, a pore size of 2-200 nm, and a specific surface area of ​​10-1000 m². 2 / g.

[0030] like Figure 2 As shown, in another aspect of this disclosure, a method S200 for preparing the aforementioned immobilized desulfurization material assembly is provided, specifically including the following steps S210~S220: S210. Provide porous particles and form a pore protection phase inside the pores of the porous particles to prevent the external surface modifying agent from entering the pores. Under the condition of the presence of the pore protection phase, perform silicon phase compatibility treatment on the outer surface of the porous particles to form an outer silicon phase compatibility layer.

[0031] In step S210, the porous particles may be at least one of molecular sieves, silica-alumina materials, porous silica, and porous alumina. Their average particle size is 20-2000 μm, pore size is 2-200 nm, and specific surface area is 10-1000 m². 2 / g.

[0032] In step S210, the pore protection phase is selected from volatile silicone oil (e.g., low viscosity end-capped PDMS), soluble wax, soluble polymer, ionic liquid, or a combination thereof.

[0033] In step S210, the silicon phase compatibility treatment is at least one of silanization, hexamethyldisilazane treatment, or siloxane brushing.

[0034] In step S210, the silicon phase compatibility treatment is performed at a temperature of 55-65°C for 3-5 hours.

[0035] S220. Remove the protective phase from the pores. After removing the protective phase from the pores, construct active sites on the inner surface of the porous particle pores to form an inner active site layer, thus forming a core-shell structured solid-supported desulfurization material combination with an outer surface compatibility and an inner pore active structure.

[0036] In step S220, the protective phase of the pores is removed by heating and evaporation, solvent elution or vacuum removal. For example, it is preferable to heat under vacuum at 75-85°C for 1.5-2.5 h, or to elute with anhydrous n-hexane 2-4 times. The solvent can be a non-polar solvent such as toluene or a polar solvent such as DMF.

[0037] In some preferred embodiments, the construction of active sites in step S220 includes immobilizing maleimide / ethylene sulfone sulfur-capturing acceptor groups or introducing Cu(I) or Ag(I) complexing sites. That is, the active sites are thiol-capturing acceptor groups or inert sulfur complexing metals. When the active site is a thiol-capturing acceptor group, an active sulfur-capturing material is formed; when the active site is an inert sulfur complexing metal, an inert sulfur complexing material is formed. By adjusting the active sites, an immobilized desulfurization material combination is formed.

[0038] It should be noted that the maleimide / ethylene sulfone sulfur-collecting acceptor group can be introduced through immobilization, with the immobilization temperature being 55-65℃ and the time being 3-5h.

[0039] It should be further noted that Cu(I) and Ag(I) complexation sites can be introduced by impregnation or ion exchange. The impregnation temperature is 55-65℃ and the time is 3-5h.

[0040] like Figure 3 As shown, another aspect of this disclosure proposes a deep desulfurization system for hydrogen-based polysiloxanes. This deep desulfurization system includes, in sequence: a raw material tank 310, a metering pump 320, a dehydration and degassing unit 330, an active sulfur chemical capture unit 340, an inert sulfur complexation and adsorption unit 350, a filter 360, a sampling and analysis unit 370, and a finished product tank 380. The raw material tank 310 is used to store hydrogen-based polysiloxane raw materials, the metering pump 320 is used to control the output flow rate of the raw materials, and the dehydration and degassing unit 330 is used to pre-treat the output hydrogen-based polysiloxane by dehydration and degassing. The active sulfur chemical capture unit 340... The acquisition unit 340 includes an active sulfur capture material for selectively and irreversibly capturing thiol-containing sulfur impurities in the pretreated hydrogen-based polysiloxane; the inert sulfur complexation adsorption unit 350 includes an inert sulfur complexation material for selectively complexing and adsorbing sulfides, sulfides, and thiophenes-containing sulfur impurities in the treated hydrogen-based polysiloxane; the filter 360 is used to filter the treated hydrogen-based polysiloxane; the sampling and analysis unit 370 is used to sample and analyze the filtered hydrogen-based polysiloxane sample; and the finished product tank 380 is used to store hydrogen-based polysiloxane with reduced total sulfur content and maintained Si-H activity.

[0041] It should be noted that the desulfurization target in this embodiment is hydrogen-based polysiloxane, which is selected from hydrogen-containing silicone oil, hydrogen-containing silicone resin, hydrogen-modified silicone resin or a mixture thereof.

[0042] It should be further noted that the active sulfur chemical capture unit in this embodiment can be a capture bed, with the packing material being an active sulfur capture material, and the inert sulfur complexation adsorption unit can be a complexation bed, with the packing material being an inert sulfur complexing material. In other words, hydrogen-based polysiloxane is sequentially contacted in series with the capture bed and the complexation bed.

[0043] It should be noted that the temperature for the above desulfurization process is set at 30-100℃, and the liquid hourly space velocity (LHSV) is 0.05-5 h⁻¹. -1 Anhydrous conditions include a feed moisture content of ≤500ppm, preferably ≤200ppm.

[0044] It should be noted that the above-mentioned filter and sampling analysis unit together form a filtration analysis unit. The filter is used to remove sulfur before filtration, and the filtration accuracy is 1-20μm.

[0045] like Figure 4 As shown, in some preferred embodiments, the sampling and analysis unit 370 includes a sampling bypass 370a, a standard microreactor 370b, an index calculation module 370c, a threshold comparison module 370d, a parameter adjustment module 370e, and a switching / alarm module 370f. The sampling bypass 370a is used to sample the treated sample; the standard microreactor 370b is used to perform a standard hydrosilylation micro-reaction under fixed platinum content, fixed temperature, and fixed vinyl / Si-H equivalent ratio conditions; the index calculation module 370c is used to obtain the induction period and gel time and define them as the addition inhibition index; the threshold comparison module 370d is used to determine whether the index reaches a preset threshold, and when the index reaches the preset threshold, it is determined that desulfurization is up to standard; the parameter adjustment module 370e is used to determine that desulfurization is not up to standard when the index does not reach the preset threshold and adjust the parameters of the desulfurization process; the switching / alarm module 370f is used to determine that desulfurization is not up to standard when the index does not reach the preset threshold, trigger an alarm, and initiate bed switching.

[0046] It should be noted that the index reaching the preset threshold includes: Si-H content retention rate ≥95% after desulfurization, total sulfur ≤1ppm after desulfurization (preferably ≤0.5ppm), and viscosity change rate at 25℃ before and after desulfurization ≤±10% (preferably ≤±5%). In other words, by periodically sampling and measuring the index A1 under fixed conditions, release is initiated when A1 ≤ the release threshold for 7.0 min; when A1 reaches 90-100% of the threshold, bed warning / switching or adjustment of operating parameters (temperature, LHSV, bypass ratio, etc.) is triggered.

[0047] It should be further noted that, to ensure the comparability of index A1, it is preferable to use a standard vinyl component (vinyl content 1 mmol / g) from a fixed source and a fixed batch, along with a fixed platinum catalyst. The fixed conditions are as follows: vinyl / Si-H equivalent ratio 0.8-1.2 (preferably 1.0); constant temperature 90℃; stirring 300 rpm; total system mass 20 g per batch; Pt concentration fixed at 10 ppm (based on the total system).

[0048] The test procedure is as follows: Weigh 10 g of the silicone resin to be tested and mix it with 10 g of the standard vinyl component under dry and inert conditions; stabilize at a constant temperature for 5 min; add platinum catalyst and start timing; record the gel time t_gel; define A1 = t_gel. When A1 ≤ 7.0 min, it is considered a release, or when A1 reaches 90-100% of the threshold, a switching / early warning is triggered.

[0049] It should also be noted that the above system should include a controller that uses an advance strategy to trigger bed switching when the additive suppression index reaches 90-100% of a preset threshold, thereby achieving automatic control.

[0050] In this embodiment, under anhydrous inert conditions, at least two desulfurization units are used in series. The first unit is a chemical capture unit for active sulfur compounds such as thiols, and the second unit is a complexation adsorption unit for inert sulfur compounds such as sulfides / sulfides / thiophenes. The desulfurization medium is a core-shell porous particle with an outer silicon phase compatibility layer and an inner active site layer. This achieves deep desulfurization while reducing viscosity drift and Si-H loss caused by the non-selective strong adsorption of the resin. Simultaneously, an addition inhibition index is defined using standard hydrosilylation microreactions for release judgment, bed life prediction, and switchover warning, achieving stable output of low-sulfur, low-loss hydrosilylation resin.

[0051] like Figure 5 As shown, in another aspect of this disclosure, a deep desulfurization method S400 for hydrogen-based polysiloxanes is proposed, comprising the following specific steps S410-S440: S410, pretreatment of hydrogen-based polysiloxane by dehydration and degassing.

[0052] In step S410, the hydrogen-based polysiloxane includes hydrogen-containing silicone oil, hydrogen-containing silicone resin, etc., with a viscosity range of 10-50000 mPa·s at 25°C. Furthermore, dehydration / degassing is preferably performed before desulfurization to ensure that the feed moisture content is ≤200 ppm, preferably ≤100 ppm.

[0053] S420. Selective and irreversible capture of sulfur-containing thiol impurities in pretreated hydrogen-based polysiloxanes using active sulfur-capturing materials.

[0054] S430: Selective complexation and adsorption of sulfur-containing impurities such as sulfides, sulfides, and thiophenes in treated hydrogen-based polysiloxanes using inert sulfur complexing materials.

[0055] S440. The treated hydrogen-based polysiloxane is filtered and sampled for analysis to obtain hydrogen-based polysiloxane with a total sulfur content that meets the requirements.

[0056] In step S440, after sampling the sample, a standard hydrosilylation micro-reaction needs to be carried out under the conditions of fixed platinum content, fixed temperature, and fixed vinyl / Si-H equivalent ratio to obtain the induction period and gel time, which are defined as the addition inhibition index. Further, it is determined whether the index reaches a preset threshold. When the index reaches the preset threshold, it is determined that the desulfurization meets the standard. When the index does not reach the preset threshold, it is determined that the desulfurization does not meet the standard, and the parameters of the desulfurization process are adjusted or an alarm is triggered and bed switching is activated.

[0057] It should be noted that the index reaching the preset threshold includes: Si-H content retention rate ≥95% after desulfurization, total sulfur ≤1ppm after desulfurization, preferably ≤0.5ppm, viscosity change rate at 25℃ before and after desulfurization ≤±10%, preferably ≤±5%.

[0058] It should be further noted that the temperature for the above desulfurization process is set at 30-100℃, and the liquid hourly space velocity (LHSV) is 0.05-5 h⁻¹. -1 Anhydrous conditions include feed moisture content ≤500ppm, preferably ≤200ppm, and filtration accuracy of 1-20μm.

[0059] Another aspect of this disclosure proposes an application of a fixed-load desulfurization material combination, which applies the aforementioned fixed-load desulfurization material combination to the refining of silicon hydrogen raw materials for addition-type silicone encapsulants, die bond adhesives, or LED encapsulation materials.

[0060] Of course, it should be understood that, in addition to the above-mentioned fixed desulfurization material combinations being applicable to the aforementioned fields, the desulfurization systems and methods mentioned above can also be applied to the refining of silicon hydrogen raw materials for addition-type silicone encapsulants, die bond adhesives, or LED encapsulation materials, and are especially suitable for stable supply and consistency control of encapsulants, die bond adhesives, and other products.

[0061] The preparation method of the solid-supported desulfurization material combination and the application of the desulfurization method will be further explained below with reference to specific embodiments. Example 1 This example illustrates a method for preparing an active sulfur-capturing material: (1) Carrier: Porous silica / alumina particles, D50=200μm, specific surface area 300 m² 2 / g, pore size 20 nm.

[0062] (2) Introduction of protective phase in pores: Vacuum degassing for 30 min, introduction of low viscosity end-capping PDMS (10 mPa·s) protective phase and removal of excess portion on the outer surface.

[0063] (3) External surface compatibility: hydroxyl-terminated PDMS brush layer grafting was used for compatibility treatment at 60℃ for 4h to obtain silicon phase compatibility layer.

[0064] (4) Remove the protective phase: vacuum / heating / solvent elution (conditions: 80℃ vacuum for 2 h or elution with anhydrous n-hexane 3 times) to restore the pore opening.

[0065] (5) Internal pore trapping sites: maleimide sulfur trapping acceptor is immobilized, toluene is used as solvent, temperature is 60℃, time is 4h, to obtain a core-shell structure active sulfur trapping material, whose porous particles have maleimide functionalization and PDMS brush layer on the outer surface.

[0066] As shown in Table 5, in the active sulfur capture material prepared in this embodiment, the outer surface coverage of the silicon phase compatibility layer is 85%, the thickness is 10 nm, the grafting amount of the hydroxyl-terminated PDMS brush layer is 2.0 wt%, the outer surface active sites are 0.15%, and the pore active sites are 1%.

[0067] Example 2 This example illustrates a method for preparing an inert sulfur complex material: Based on the surface compatibility of Example 1, molecular sieves were selected as porous particles, and Cu(I) complexation sites were introduced through impregnation / ion exchange. Toluene was used as the solvent, the temperature was 60°C, and the time was 4 h. The metal loading was 20 wt%, resulting in a core-shell structured inert sulfur complex material with Cu(I) active sites inside the molecular sieve and a PDMS brush layer on the outer surface.

[0068] Example 3 This example illustrates a two-stage fixed-bed desulfurization process: 1) Perform dehydration and degassing pretreatment on hydrogen-containing MQ siloxane resin (Ex-A1). For parameter information of hydrogen-containing MQ siloxane resin, please refer to Table 1. 2) The active sulfur capturing material prepared in Example 1 was loaded into an active sulfur chemical capturing bed (bed A), and the inert sulfur complexing material prepared in Example 2 was loaded into an inert sulfur complexing adsorption bed (bed B). Bed A and bed B were then connected in series. The active sulfur capturing material in bed A was used to selectively and irreversibly capture the sulfur-containing thiol impurities in the pretreated hydrogen-based polysiloxane. 3) Utilize the inert sulfur complexing material in bed B to selectively complex and adsorb sulfur-containing impurities such as sulfides, sulfides, and thiophenes in the treated hydrogen-based polysiloxane; 4) The treated hydrogen-based polysiloxane is filtered and sampled for analysis to obtain hydrogen-based polysiloxane with a total sulfur content that meets the requirements.

[0069] Feed index A0: viscosity at 25℃ 20000 mPa·s, Si-H 0.85 mmol / g, total sulfur 8.0 ppm, moisture 150 ppm; moisture content after dehydration ≤80 ppm.

[0070] Desulfurization conditions: temperature 60℃, LHSV 1.0 h -1 Nitrogen atmosphere, filtration accuracy of 5μm, as shown in Table 2; Test results: Total sulfur 0.35 ppm, Si-H retention rate 98.2%, viscosity change +2.5%, Al=6.5 min (SD=0.3 min), as shown in Tables 3 to 5.

[0071] Comparative Example 1 As shown in Table 2, hydrogen-based polysiloxane (CE-A1) is desulfurized using a general-purpose bed, which includes only bed A, and the packing material for bed A is activated carbon / kaolin (1:1, w / w).

[0072] The desulfurization conditions were the same as in Example 3.

[0073] Test results: Total sulfur decreased to 1.20 ppm, but Si-H retention rate was 92.0%, viscosity changed by +15.0%, and Al fluctuated significantly (SD=1.2 min), as shown in Tables 3 and 4.

[0074] Comparative Example 2 As shown in Table 2, hydrogen-based polysiloxane (CE-A2) uses only the B bed for desulfurization, wherein the B bed packing is a complexing agent (Cu(I)-molecular sieve).

[0075] The desulfurization conditions were the same as in Example 3.

[0076] Test results: Total sulfur 0.80 ppm, Si-H retention rate 97.5%, viscosity change +4.0%, but Al=8.5 min is still higher than the release threshold of 7.0 min (SD=0.6 min), as shown in Tables 3 and 4.

[0077] Comparative Example 3 As shown in Table 2, hydrogen-based polysiloxane (CE-A3) uses only bed A for desulfurization, where the packing material of bed A is a scavenging agent (maleimide-functionalized silica gel).

[0078] The desulfurization conditions were the same as in Example 3.

[0079] Test results: A1 = 7.8 min and total sulfur 2.00 ppm is higher than the target of 0.50 ppm, as shown in Tables 3 and 4.

[0080] Comparative Example 4 As shown in Table 2, hydrogen-based polysiloxane (CE-A4) uses core-shell-free A-bed and B-bed for desulfurization. The A-bed is filled with incompatible A-bed filler (maleimide silica gel without external surface compatibility), and the B-bed is filled with incompatible B-bed filler (Cu(I)-molecular sieve without external surface compatibility).

[0081] As shown in Table 5, in the sulfur-capturing material provided in this embodiment, the outer surface coverage is 10%, the thickness is 0.5 nm, the grafting amount is 0.2 wt%, the outer surface active sites are 0.8%, and the pore active sites are 1%.

[0082] The desulfurization conditions were the same as in Example 3.

[0083] Test results: Total sulfur 0.40 ppm but viscosity drift +12.0%, Si-H retention rate 94.0%, with fluctuations (SD=0.8 min), as shown in Tables 3 and 4.

[0084] It should be noted that the total sulfur content in the above examples and comparative examples was determined by combustion-UV fluorescence method, in ppm; Si-H content was determined by titration, in mmol / g; Si-H retention rate (%) = (discharge Si-H content / feed Si-H content) × 100%; viscosity change rate at 25℃ (%) = (discharge viscosity - feed viscosity) / feed viscosity × 100%; outer surface coverage was quantified by XPS or outer surface contact angle distribution, in %; equivalent thickness was obtained by TEM cross-section or XPS depth profile analysis, in nm; grafting amount / grafting density was expressed as wt% and mmol / m² by TGA or elemental analysis combined with specific surface area conversion. 2 or chains / nm 2 .

[0085] Table 1. Raw material parameter information

[0086] Table 2. Process and bed configuration parameters for Example 3 and each comparative example.

[0087] Table 3. Desulfurization results of Example 3 and each comparative example.

[0088] Table 4. A1 endpoint criteria for Example 3 and each comparative example (fixed conditions: Pt 10 ppm; temperature 90°C; Si-H / Vi=1.0; standard vinyl components; stirring 300 rpm)

[0089] Table 5. Characterization results of core-shell compatible layer and selective distribution in Example 3 and Comparative Example 4

[0090] This disclosure presents a solid-supported desulfurization material combination, its preparation method, application, and a deep desulfurization system and method using hydrogen-based polysiloxanes, which have the following advantages compared to existing technologies: (1) In view of the current problem that it is impossible to achieve deep removal of both active sulfur and inert sulfur, this disclosure achieves synergistic deep removal of different sulfur forms by connecting two desulfurization materials in series and treating them separately. (2) In view of the problems of viscosity drift and Si-H loss caused by current solid treatment, the desulfurization material disclosed herein adopts a core-shell structure, and the compatibility layer on its outer surface is used to reduce non-selective adsorption and reduce viscosity drift and Si-H loss. (3) This disclosure also establishes an endpoint criterion directly related to application curing by strongly correlating the addition inhibition index with the addition curing sensitivity, thereby enabling release and bed management, making the process more controllable, and achieving automatic desulfurization; (4) The selective compatibility preparation method disclosed herein makes the core-shell structure quantifiable and reproducible, thereby improving the batch-to-batch consistency of materials and the patent barrier.

[0091] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A fixed-load desulfurization material assembly, characterized in that, include: Active sulfur-capturing materials and inert sulfur-complexing materials; among them, The active sulfur capturing material is used to selectively and irreversibly capture sulfur-containing thiol impurities. It includes a first inner layer formed by porous particles, thiol capturing acceptor groups located in the pores of the porous particles, and a first silicon phase compatibility layer wrapped around the outer surface of the first inner layer. The inert sulfur complexing material is used for selective complexation and adsorption of sulfur-containing impurities such as sulfides, sulfides, and thiophenes. It includes a second inner layer formed by porous particles, an inert sulfur complexing metal located in the pores of the porous particles, and a second silicon phase compatibility layer wrapped around the outer surface of the second inner layer.

2. The fixed-support desulfurization material assembly according to claim 1, characterized in that, The thiol capture acceptor group is selected from at least one of maleimide group, vinyl sulfone group, activated acrylate group and activated haloalkyl group.

3. The fixed-support desulfurization material assembly according to claim 1, characterized in that, The inert sulfur complex metal comprises Cu(I) and / or Ag(I).

4. The fixed-support desulfurization material assembly according to claim 1, characterized in that, Both the first silicon phase compatibility layer and the second silicon phase compatibility layer are siloxane brush layers; wherein, The siloxane brush layer is a hydroxyl-terminated polydimethylsiloxane segment.

5. The fixed-support desulfurization material assembly according to claim 4, characterized in that, The coverage of the siloxane brush layer is 30-100%, and the equivalent thickness is 0.5-200nm; The grafting amount and grafting density of the siloxane brush layer satisfy at least one of the following: The organic layer mass fraction, calculated by thermogravimetric analysis, is 0.1-10 wt%. The grafting amount per unit external surface area is 0.01-5 mmol / m². 2 ; The chain density is 0.01-5 chains / nm. 2 .

6. The fixed-support desulfurization material assembly according to claim 1, characterized in that, The porous particles are selected from at least one of molecular sieves, silica-alumina materials, porous silica, and porous alumina. The porous particles have an average particle size of 20-2000 μm, a pore size of 2-200 nm, and a specific surface area of ​​10-1000 m². 2 / g.

7. A method for preparing a fixed-support desulfurization material composition as described in any one of claims 1 to 6, characterized in that, The method includes: Porous particles are provided, and a pore protection phase is formed inside the pores of the porous particles. The outer surface of the porous particles is subjected to silicon phase compatibility treatment to form a silicon phase compatibility layer. The protective phase of the pores is removed, and active sites are constructed on the inner surface of the porous particle pores to form a core-shell structured desulfurization material assembly with an outer surface compatibility and an active inner pore structure; wherein... The active site is a thiol capture acceptor group or an inert sulfur complex metal.

8. A deep desulfurization system for hydrogen-based polysiloxanes, characterized in that, The deep desulfurization system includes: The dehydration / degassing unit is used for dehydration and degassing pretreatment of hydrogen-based polysiloxanes. An active sulfur chemical capture unit, comprising an active sulfur capture material according to any one of claims 1-6, for selectively and irreversibly capturing sulfur-containing thiol impurities in pretreated hydrogen-based polysiloxanes; An inert sulfur complex adsorption unit, comprising an inert sulfur complexing material according to any one of claims 1-6, is used for selective complex adsorption of sulfur-containing impurities such as sulfides, sulfides, and thiophenes in treated hydrogen-based polysiloxanes. The filtration and analysis unit filters the processed hydrogen-based polysiloxane, takes samples for analysis, and obtains hydrogen-based polysiloxane with reduced total sulfur content while maintaining Si-H activity.

9. A method for deep desulfurization of hydrogen-based polysiloxanes, characterized in that, The deep desulfurization method includes: Pretreatment of hydrogen-based polysiloxanes by dehydration and degassing; The active sulfur-capturing material of any one of claims 1-6 is used to selectively and irreversibly capture sulfur-containing thiol impurities in pretreated hydrogen-based polysiloxanes. The inert sulfur complexing material of any one of claims 1-6 is used to selectively complex and adsorb sulfur-containing impurities such as sulfides, sulfides, and thiophenes in the treated hydrogen-based polysiloxane. The treated hydrogen-based polysiloxane was filtered and sampled for analysis to obtain hydrogen-based polysiloxane with a total sulfur content that met the requirements.

10. An application of a fixed-load desulfurization material combination, characterized in that, The combination of solidified desulfurization materials according to any one of claims 1 to 6 is used in the refining of silicon hydrogen raw materials for addition-type silicone encapsulants, die bond adhesives, or LED encapsulation materials.

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