KR100953734B1 - Reclaimed silicone oil using waste silane hydrolysate, process for preparing them same and uses of the same - Google Patents

Abstract

The present invention relates to a regenerated silicone oil using waste silane hydrolyzate, a method for producing the same, and a use thereof, wherein the waste silane hydrolyzate is treated with alkali to remove hydrosilane present as an impurity and trihydroxy silane causing gelation, Regenerated silicone oil, characterized in that it is composed of the remaining residues by oxidizing the disilane and trisilane as impurities to the useful siloxane to remove impurities as much as possible, and after the decolorization polymerization filter process, distillation to remove the low boiling point solvent To provide.

Waste Silane Hydrolyzate, Regenerated Silicone Oil

Description

Reclaimed silicone oil using waste silane hydrolysate, process for preparing them same and uses of the same}

The present invention relates to a regenerated silicone oil using waste silane hydrolyzate, a method for producing the same, and a use thereof, and a regenerated silicone oil obtained by purifying waste silane hydrolyzate discharged from a silicon major company, a method for preparing the same, and a regenerated silicone oil. It is related with the use used as a plasticizer, a mold release agent, etc.

Dow Corning, MPM (formerly GE / Bayer), Wacker Silicone, and Rhodia, which are currently producing genuine silicone oils, use silicon metal powder and methyl chloride. Dimethyldichlorosilane required for silicone rubber (HTV, LSR, RTV-2) and sealant (RTV-1) in a crude silane mixture produced by gas phase reaction in a column reactor at 250 to 300 ° C. (dimethyldichlorosilane (M2) and trimethylchlorosilane (M3) are fractionally distilled to make oils and polymers, and methyltrichlorosilane (M1) is used to make crosslinkers, which are sealant curing agents. The remaining distillation residues (waste silane hydrolysates) are aliphatic hydrocarbons and trisils which have a high boiling point with M1 + M2 + M3 azeotropic mixtures and disilanes which are not fractionally distilled. As a composite of silane (trisilane), it is no longer useful, and has been incinerated or mixed with quicklime and buried underground.

Such waste silane hydrolyzate is called MS oil (methyl siloxane oil) or waste silane hydrolysate and emits about 2-4% of the production capacity (capacity) in the production of genuine silicone oil. As a result, the world's silicon major companies emit tens of thousands of tonnes of waste silane.

This not only pollutes the global environment, but also raises the cost of collecting the scattering of SiO ₂ fumed silica, which is a nanoparticle generated when incinerated. Incineration of one tonne of waste generates about 200 to 250 kg of fumed silica powder.

Conventional methods for producing regenerated silicone oils include alkaline catalysts such as caustic soda (sodium hydroxide) or caustic gallium (potassium hydroxide) for waste silicon compounds such as waste silicone rubber, cured sealant scrap, and silicone polymers and resins that have exceeded the shelf life during storage. Distillation of monomeric silane (dimethylcyclic silane) by high temperature heat treatment cracking in an inert, high boiling point solvent under the distillate is polymerized or polycondensation reaction under an alkali or acidic catalyst to synthesize regenerated silicone oil.

As such, the conventional process for producing regenerated silicone oil from waste silane hydrolyzate, i.e., cracking-> distillation-> cyclic silane recovery-> oil synthesis, is not available due to the gelation of the reactants in the cracking process.

However, multinational silicon major companies have been trying to find a partner that can recycle these waste silane hydrophiles for many years to solve the environmental problems caused by incineration or landfill. Because conventional alkali cracking methods, trihydroxysilane in the waste silane hydrolyzate immediately creates a network crosslinked polymer, which gels the entire reactant and renders the reaction plant incapable of rejecting it. . This is because waste silane hydrochloride is being viewed as non-recyclable.

It is an object of the present invention to produce recycled silicone oil which can replace genuine silicone oil and organic plasticizer which are used as the main raw material plasticizer of high value-added sealant using waste silane hydrolyzate.

In order to achieve the above object, the present invention treats waste silane hydrolyzate with alkali to remove hydrosilane present as an impurity and trihydroxy silane causing gelation, and treats with an oxidizing agent to dissolve disilane and trisilane as impurities. It is oxidized to siloxane to remove impurities as much as possible, and after the decolorization polymerization filter process is distilled to remove the low boiling point solvent to provide a regenerated silicone oil, characterized in that consisting of the residue.

The present invention also treats waste silane hydrolyzate with alkali to remove hydrosilane present as an impurity and trihydroxy silane that causes gelation, and oxidizes disilane and trisilane as impurities to useful siloxane by treating with an oxidant. To remove as much as possible, after the decolorization polymerization filter process, and distillation to remove the low boiling point solvent to provide a method for producing a regenerated silicone oil, characterized in that to utilize the remaining.

The alkali used in the present invention is KOH or NaOH, and the oxidizing agent is preferably NaOCl or CaOCl ₂ .

In the present invention, the decolorization polymerization filter process is performed by adding activated carbon and a catalyst (TMAH, etc.) to perform depolymerization and simultaneous polymerization, followed by filtration after the polymerization is completed.

In addition, the present invention provides a method of using a recycled silicone oil made from waste silane hydrolyzate as a raw material to manufacture a sealant by replacing a genuine silicone oil which is a plasticizer of a conventional silicone sealant.

The present invention also produces plywood and sheet metal formwork by emulsifying recycled silicone oil made using waste silane hydrolyzate or as a release agent for concrete shuttering panels using the oil itself. Provide a method of use.

The present invention is not a method of cracking a cyclic silane as a silicone oil monomer by cracking as in the prior art, but oxidizing the silane compound as an impurity into siloxane by pretreatment and decolorization polymerization of waste silane hydrochloride itself and evaporating unnecessary low boiling point solvent. It is characterized by utilizing the remaining residues removed.

In the present invention, silicon (silicone) is a silicon resin, a synthetic resin, a high molecular compound consisting of silicon, oxygen, and hydrocarbons, and silane is one of a series of silicon hydrides and hydrocarbons, and a general formula Si _n H _{2n +2} , and a siloxane ( siloxane) occurs when the general formula _{[(CH 3) 2 SiO]} n , and the action of water in the halogen substituents of the silane as a generic name of a compound consisting of a siloxane bond (SiO).

This invention improves the manufacturing method of the conventional regeneration silicone oil which was not available because of gelation of a reactant, etc., and provides the regeneration silicone oil which can be used as a plasticizer of the sealant with a very high added value from waste silane hydrolyzate, etc.

In order to solve the above-mentioned problems of the prior art, the present inventors have succeeded in developing a regenerated silicone oil which can be used as a substitute for a plasticizer of a very high value-added sealant by accomplishing the experiment of the following procedure.

1. Analysis of Waste Silane Hydrolyzate

As a result of analyzing the waste silane hydrolyzate by GC, it was confirmed that it consists of the composition of Table 1.

ingredient Content (% by weight) C ₆ H ₆ 12.02 C ₆ H ₁₈ OSi ₂ 13.35 C ₇ H ₁₆ 2 C ₆ H ₁₈ Si ₂ 30.07 C ₈ H ₁₈ 6.1 C ₈ H ₁₆ 3.11 C ₉ H ₂₀ 14.86 C ₈ H ₂₄ O ₂ Si ₃ 4.23 C1 ₂ H ₃₀ OSi ₄ 10.85 C ₈ H ₂₄ O ₄ SiO ₄ 3.41 Sum 100

Reclassification of the materials is shown in Table 2.

ingredient Content (% by weight) 1) Hexane, heptane, other hydrocarbons 25-35 2) Hexamethyldisiloxane, other trisiloxanes 10-15 3) D3, D4, D5 *, other cyclic compounds 25-35 4) disilane, trihydroxysilane, other hydrosilane 10-15 Sum 100 * D3 = Hexamethylcyclotrisiloxane * D4 = Octmethylcyclotetrasiloxane * D5 = Decamethylcyclopentasiloxane

Of these substances, 2) and 3) may be usefully used as a constituent of silicone oil, but the substances of 4) are not separated by distillation and participate in the polymerization. To cause gel or coagulation.

2. Removal method of disilane

The disilane's -Si-Si- bond energy (54 kcal / mol) is very small compared to the bond energy of other siloxane bonds (Si-O) (111 kcal / mol), so it is easily incised by generator active oxygen. It can be cleaved and oxidized to convert into useful siloxane bonds, namely -Si-O-Si-.

For this purpose, the disilane was removed by injecting oxygen under a constant pressure and temperature, or by treating with a strong oxidizing agent such as NaOCl, CaOCl ₂ .

3. Removal method of hydrosilane

(CH ₃ ) ₃ -Si-H, or Si-H, reacts with alkalis such as KOH to generate hydrogen gas, making Si-OH and useful siloxane Si-O-Si bonds.

4. Removal method of trihydroxy silane (trifunctional group)

CH ₃ -Si- (OH) ₃ reacts with an alkali such as KOH to form CH ₃ -Si (OH) ₂ OK. Since foreign matter is water soluble, it is dissolved in the water layer and separated.

As the experiment was repeated, it was confirmed that a considerable amount of unnecessary components can be converted or removed.

Example 1

About 500 g of 5% KOH aqueous solution was added to 500 g of the silane hydrolyzate from which the hydrochloric acid layer was removed as much as possible in a strong homomixer, followed by vigorous stirring at 40 ° C. for about 1 hour, followed by stirring in an emulsion state. Free hydrochloric acid contained in the oil and chlorosilanes still unreacted were completely hydrolyzed.

In this process, methylhydrosilane releases hydrogen gas and is converted into methylsiloxane, and trifunctional silane, which forms a network, is converted to potassium methylsiliconate, which is water-soluble. It was dissolved in the water layer and separated and removed in the next step.

To this was again added 200 g of 12% NaOCl and vigorously stirred for about 24 hours to oxidize the disilane and trisilane present as impurities into useful siloxanes.

The pretreatment was completed by separating the oil and water layers by turning off the stirrer and standing for about 48 hours, followed by decantation of the lower aqueous layer.

[Example 2]

3 g of activated carbon and 1.5 g of 25% TMAH (tetramethylammoniumhydroxide) as a catalyst were added to 300 g of the silane hydrolyzate pretreated in Example 1, and polymerization was carried out simultaneously with decolorization with stirring at 140 ° C. for 7 to 8 hours.

When the polymerization was completed, the mixture was cooled to 60 ° C., filtered, and the viscous colorless transparent filtrate was transferred to a vacuum distillation tube to remove the low boiling hydrocarbon by vacuum distillation while gradually increasing the temperature from room temperature to 160 ° C.

In this case, since the catalyst TMAH is decomposed at 155 ° C., it is necessary to maintain the temperature below 150 ° C. to maintain an equilibration reaction in order to make a high viscosity oil.

Thus, 225 g (yield 75%) of regenerated silicone oil (Our brand Silflex350) which has the characteristic of Table 3 was obtained.

Exterior Slightly yellowish Viscosity (20 ° C Brookfield rotor # 1) 360 cSt (Centistokes) Specific gravity (20 ℃) 0.978 N.V (150 ° C., 1 hr) 91%

A comparison graph of the IR spectrophotometer of the genuine silicone oil and the regenerated silicone oil (silflex350) shows that the properties are almost similar (see FIG. 1). Figure 1 (a) is a comparison graph of the IR spectrophotometer of genuine silicone Kinematic Viscosity 350cSt (Centistokes), Figure 1 (b) IR spectroscopy of regenerated silicone oil (silflex350) according to the present invention having a kinematic viscosity of 350cSt Photometer graph.

Example 3

As shown in Table 4, the regenerated silicone oil (Silflex350) prepared in Example 2 was replaced with the original genuine silicone oil, and the polymer and plasticizer (silicone oil) part was reduced by about 10% in order to meet the properties of the existing product. As a result of the production of the sealant in the formulation of about 10% increase in calcium, the physical and chemical properties of the product were equally good as shown in Table 5. This formulation also has the effect of significantly reducing production costs.

Sealant manufacturing compounding ratio Existing formulation (part by weight) Silflex 350 blend (parts by weight) OH-polymer (80000 cSt) 300 270 Genuine Silicone Oil (350 cSt) 100 0 Silflex 350 0 90 Crosslinking Agent (MOS + VOS) 50 50 Adhesion promoter 10 10 CaCO ₃ Powder 400 444 Silica (Aerosil A150) 45 45 Dibutyltindilaurate (DBTDL) One One

Sealant physical properties Original formulation Silflex 350 formulation Elongation 400% 400% Tensile strength 2.4 2.4 Shore A hardness 22 23 Surface free time (Tack free time, Min) 25 30 Through Cure (mm in 24hr) 3 2.4

As can be seen from Table 5, the result was comparable as a sealant plasticizer.

Example 4

400 g of regenerated silicone oil (Silflex 350) prepared in Example 2 and 3.5 g of a polyoxyethylene nonylphenylether nonionic surfactant having a hydrophobic lipophilic balance (HLB) of about 10 were added to 600 g of water Emulsions were made in a homogenizer.

The emulsion thus diluted is well diluted in water, applied to plywood formwork specimens in 5-fold dilutions and dried, and the cement mortar cured under 3 kg / cm 2 pressure.

After 10 days of curing, the formwork was completely separated.

1 is an IR spectrophotometer graph of a genuine silicone oil and a regenerated silicone oil (silflex350) according to the present invention.

Claims (6)

delete The waste silane hydrolyzate is treated with alkali to remove hydrosilane present as an impurity and trihydroxy silane which causes gelation, and treated with an oxidizing agent to oxidize the disilane and trisilane as impurities into useful siloxanes to remove impurities, and to decolorize. After passing through the polymerization filter step, distilled to remove the low-boiling solvent, the remaining residue is used for producing a regenerated silicone oil. The method of claim 2, wherein the alkali is KOH or NaOH and the oxidizing agent is NaOCl or CaOCl ₂ . The method of claim 2, wherein the decolorization polymerization filter step is performed by adding activated carbon and a catalyst to carry out the polymerization reaction simultaneously with the decolorization reaction, followed by filtration after completion of the polymerization. A method of producing a sealant by using the regenerated silicone oil produced by the method of claim 2 in place of a genuine silicone oil which is a plasticizer of a conventional silicone sealant. A process for producing plywood and sheet metal formwork by emulsifying the regenerated silicone oil produced by the method of claim 2 or using the oil itself as a release agent for building concrete formwork.

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