EP2791259A1

EP2791259A1 - Silicone solvent

Info

Publication number: EP2791259A1
Application number: EP12795474.1A
Authority: EP
Inventors: Andreas KÖLLNBERGER
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 2011-12-16
Filing date: 2012-12-06
Publication date: 2014-10-22
Also published as: US20140336093A1; JP5951796B2; KR20140096362A; CN103998537B; DE102011088885A1; CN103998537A; JP2015505886A; KR101636390B1; WO2013087510A1; US9309488B2; TW201326385A

Abstract

The invention relates to a silicone solvent containing A) at least one tetraalkylammonium fluoride, B) at least one inorganic base which is capable of binding hydrogen ions, and C) at least one solvent which is suitable for dissolving the tetraalkylammonium fluoride A) as well as at least 0.001 wt.% of the inorganic base B).

Description

Silicon remover

The present invention relates to a composition for depolymerization and removal of silicone residues. This composition, called a silicone remover, contains a

Alkylammonium fluoride, an inorganic basic salt and a solvent. The composition of the invention is particularly suitable for removing crosslinked or uncrosslinked, filled or unfilled silicone residues from sensitive surfaces and substrates. The silicone solubilizer can be liquid, pasty or gelatinous in a variety of applications, depending on the application.

In the prior art are for the removal or the

Depolymerization of crosslinked or uncrosslinked silicones various methods and compositions known.

• Sources and remove with the help of an organic or

halogenated organic solvent.

• Sources and remove with the help of an amine like

for example, diisopropylamine.

Depolymerization of the polydimethylsiloxane with the aid of alkaline solutions of strong bases, such as sodium hydroxide, potassium hydroxide, as described, for example, in US Pat. No. 2,710,843

described.

• Depolymerization by means of short-chain or

cyclic oligodiorganosiloxanes such as in DE

69122740 T2.

Depolymerization by aqueous solutions of strong acids such as alkylbenzenesulfonic acids, sulfuric acid, Hydrofluoric acid as described for example in JP 8250400 A.

Depolymerization by means of a composition

containing phosphonitrile halide compounds and

short-chain oligodimethylsiloxanes of up to 7-Si chain members as described, for example, in EP 0 884 368 A1. The opposite use of cyclic or linear phosphonitrile halide compounds as

Polymerization or condensation catalyst for

Preparation of long-chain polydimethylsiloxanes has long been state of the art as well as the use of the catalyst for the equilibration of polydimethylsiloxanes as described in DE 196 07 264 A1.

US 5,008,229 is directed to solutions of phosphonitrilic chlorides in an organic solvent and to the use of such compositions for accelerating the

Condensation and / or equilibration of hydroxy-terminated diorganosiloxanes directed.

Although improved results are achieved, an organic solvent such as ethyl acetate is used to facilitate dissolution of the phosphonitrile chloride. DE 37 25 377 eliminates the use of an organic

Solvent by using a reaction product of a phosphorus-nitrogen chloride and a cyclic diorganosiloxane, such as octamethylcyclotetrasiloxane, as a catalyst. However, experience has shown that

Reaction products of phosphorus-nitrogen-chloride and octamethylcyclotetrasiloxane often have viscosities exceeding several thousand mPa-s (centipoises), which makes the materials less suitable as catalysts for the removal of polydimethylsiloxane backbones.

US Pat. No. 7,232,770 Bl describes ammonium fluorides in combination with amines in various solvents for removing silicon residues in the semiconductor sector.

The disadvantage of all previously known compositions for dissolving silicone is that they contain corrosive substances such as

For example, organic acids or alkalis, which in the removal of silicones from various substrates, for

Surface corrosion of metals lead.

The object of the present invention was therefore a

Composition, which is suitable for removing crosslinked and uncrosslinked polysiloxane residues from various substrates or between substrates, at the same time inert to the substrates, and this does not damage or corrode even in a thin layer during the exposure time, to remove the silicone impurities. This object has surprisingly been achieved by a silicone solubilizer

A) at least one tetraalkylammonium fluoride,

B) at least one inorganic base capable of binding hydrogen ions and C) at least one solvent capable of dissolving both the tetraalkylammonium fluoride A) and at least 0.001% by weight of the inorganic base B).

Surprisingly, it has been found that inorganic salts are particularly suitable, the corrosive action of a silicone dissolving composition of an organic tetraalkylammonium fluoride and a solvent

suppress .

The silicone solubilizers according to the invention are particularly well suited for removing polysiloxane residues or layers on or between substrates.

The silicone solubilizers according to the invention have the advantage that they act selectively on silicone polymers or polydimethylsiloxane groups. Other plastics are not affected by the mechanism of the reaction. Example of plastics inert to the silicone solubilizer according to the invention:

Polyolefin, polystyrene, polyvinyl chloride, polyethylene,

Polypropylene, polynitrile, acrylonitrile-butadiene-styrene copolymers, polyimides, or polyacrylate. Silicone solubilizers according to the invention merely dissolve, for example, addition-crosslinked, condensation-crosslinked and peroxydically crosslinked silicone rubbers such as RTV-1, RTV-2, LSR and HTV. The silicone solubilizer according to the invention also works

Silicone rubbers, depending on the application further

Contain components such as fillers, for example hydrophilic or hydrophobic silicic acids, precipitated silicas,

Silicone resins, aluminum oxides, titanium oxides, carbon blacks, graphites, metals, metal carbonates, diatomaceous earths, metal dusts, fibers such as glass fibers or plastic fibers and other additives such as fungicides, fragrances, corrosion inhibitors,

Oxidation inhibitors, light stabilizers, flame retardants, dispersing agents, adhesion promoters,

Pigments, plasticizers, organic polymers or

Be heat stabilizers. Also copolymers that Polydiorganosiloxaneinheiten or silicone resins are degraded by the silicone solubilizer according to the invention.

In a preferred embodiment, component A) corresponds to the general formula (1): wherein

n = 1 to 30, preferably n = 1 to 18 and particularly preferably n = 1 to 10

means.

The compounds A) have long been known in the art and are commercially available. examples for

preferred compounds A) are: tetramethylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride,

Tetrapentylammonium fluoride, tetrahexylammonium fluoride,

Tetraheptylammonium fluoride, tetraoctylammonium fluoride,

Tetranonylammonium fluoride, tetradecylammonium fluoride,

Tetraisopropylammonium fluoride, tetraisobutylammonium fluoride, tetra (ter-butyl) ammonium fluoride, tetra (tert-pentyl) ammonium fluoride.

In a preferred embodiment, component B) is selected from the following group of inorganic salts, wherein M is selected from the group of alkali metals and alkaline earth metals and monovalent cations such as, for example, the ammonium ion: Salts of the phosphorous and phosphoric acids M _o H _p PO ₃ and M _o H _p PO ₄ with o = 1 to 3 (empirical formula based on a monovalent metal cation, by way of example) and p = 0 to 2,

Salts of sulfuric and sulfuric acids M _q H _r SO ₃ , M _q H _r SO ₄ _where q = 1 to 2, r = 0 to 1,

Salts of nitrous and nitric acid MN0 ₂ and MN0 ₃ (empirical formula based on a monovalent

Metal cation). Preferred as M are sodium, potassium, magnesium, calcium and ammonium. Particularly preferred compounds B) are Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , MgHPO ₄ , Mg ₃ (PO ₄ ) _2, (NH ₄ ) H ₂ PO ₄ , (NH ₄ ) ₂ HPO ₄ , ( NH ₄ ) ₃ PO ₄ .

Component C) is a solvent which is capable of dissolving component A) and at least 0.001% by weight of component B). Examples of the component C) are linear, branched and cyclic ethers which may also contain other heteroatoms such as nitrogen, phosphorus or halogen atoms. The following are, without limiting the scope of the invention, examples of ethers as solvents: dialkyl ethers: diethyl ether, di-n-propyl ether, diisopropyl ether, dibutyl ether, dipentyl ether, dihexyl ether, dioctyl ether, 2-ethylhexyl vinyl ether, 4-chlorobutyl ether, dichloromethyl methyl ether, 1, 2 -Dirnethoxypropan, tert. - Amyl methyl ether, tert. Butyl ethyl ether, di-sec. butyl ether, tetraethylene glycol dimethyl ether; cyclic ethers:

Oxacyclopentane (tetrahydrofuran), oxacycloheptane

(Tetrahydropyran), 1-4-dioxane; Ethers containing aromatic groups: methyl phenyl ether, 2-nitrophenyl phenyl ether,, 4-dimethoxybenzene, 1, 3, 5-trimethoxybenzene, butyl phenyl ether, 1, 4 -Diethoxybenzol. Another class of compounds which can preferably be used as component C) is the substance class of the ketones which contains linear, branched and cyclic compounds which may additionally contain further heteroatoms such as nitrogen, phosphorus or halogen atoms. Particularly preferred are linear and branched aliphatic molecules.

In the following, without the scope of the invention

Examples of ketones within the meaning of component C) are listed below:

2-propanone, 2-butanone, 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, 2-decanone, 3-hexanone, 3-heptanone, 3-octanone, 3-nonanone, 3 Decanone, 2-methyl-3-butanone, 3,3-dimethyl-2-butanone, 2-methyl-3-pentanone, 2-methyl-3-hexanone, 2-methyl-3-heptanone, 4-heptanone, 4- Octanone, 4-nonanone, 4-decanone, 2, 2-dimethyl-3-pentanone, 2, 4-dimethyl-3-pentanone, 5-methyl-3-heptanone, 4, 4 -dirnethyl-2-pentanone, 2, 2, 4, 4, -tetramethyl-3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 3,3-dimethoxy-2-butanone, 4, 4-dimethoxy-2-butanone, 3 Methyl 2-cyclohexanone, 3-methyl-2-cyclohexenone, 1, 3-cycloheptanedione, 2-methyl-1, 3-cyclohexanedione, 3-ethoxy-2-cyclopenten-1-one, 5-methyl-1,3 cyclohexanedione, triacetylmethane, 2,2-dimethylcyclopentanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, cycloheptanone,

Diethylaminoacetone.

Another class of compounds that can be used preferably as component C) is the class of esters containing linear, branched and cyclic compounds which

additionally further hetero atoms such as nitrogen, phosphorus or May contain halogen atoms. Particularly preferred

Esters which are considered to be dipolar aprotic solvents.

In the following, without the scope of the invention

Examples of esters within the meaning of component C) are listed below:

Carboxylic acid alkyl ester methyl acetate,

Ethyl acetate, propyl acetate,

Butyl acetate, pentyl acetate,

Ethoxylated hexyl ester, heptyl acetate,

Octyl acetate, acyl acetate,

Propionic acid methyl ester, ethyl propionate,

Propionic acid propyl ester, butyl propionate,

Propionic acid pentyl ester, hexyl propionate,

Propionic acid heptyl ester, octyl propionate,

Preferably, C) is selected from the group of the following

Solvents: alkyl carboxylates, dialkyl ethers, alkyl aryl ethers, ketones. We particularly prefer C) selected from the group: ethyl acetate, propyl acetate,

Isopropyl acetate, 2-butanone, 2-octanone, isopropyl methyl ketone, tert-butyl methyl ketone.

As a further optional component, silicone solvents according to the invention may contain thickener D) in order to adjust the viscosity and, for example, prepare pasty masses. Examples of thickeners D) are: precipitated silica, hydrophilic or hydrophobic finely divided silica,

Alumina, titania, calcium salts of carboxylic acids, carbon blacks or carboxymethylcellulose. It is possible to use all thickeners D) known from the prior art which have a water content of less than 5000 ppm. Prefers the water content should be below 2500 ppra and

more preferably below 1000 ppm. Also, organic aliphatic alcohol groups are to be avoided in the composition, since these, analogous to water, for the hydrolysis of

Component A) and the silicone solvent would lose its equilibrium property. D) is preferred from the

Group of fumed silicas selected.

The preparation of the silicone solvent according to the invention is carried out by mixing A) with B) and C) and possibly D) ideally until the formation of a clear solution.

Preference is given to 0.1 to 10% by weight of A), more preferably 0.1 to 5% by weight of A) to 100% by weight of silicone solvent. Preference is given to 0.001 to 1 wt.% B), particularly preferably 0.01 to 0.5 wt.% B), to 100 wt.% Of silicone solubilizer. C) represents the remainder of the 100% by weight of the silicone solubilizer.

The mixing is usually carried out by intensive stirring of the components between 0.5 and 10 hours at room temperature or elevated temperature (up to 140 ° C).

If thickeners D) are used, this is done by adjusting the viscosity of the silicone solubilizer according to the invention to a defined range. This is the

Thickener D) in amounts of 0.1 to 30 wt.% Used to 100 wt.% Silicone Solvent. From 0.5 to 10% by weight and more preferably from 1 to 5% by weight of D) are preferably added.

Another object of the present invention is the use of the silicone solubilizer according to the invention for

Depolymerization and removal of crosslinked or uncrosslinked silicone residues of surfaces or substrates.

Depending on the viscosity of the silicone solvent according to the invention - liquid, pasty or gel - this is done in various ways, such as spraying or applying the

Silicone Solvent according to the invention to be purified

Object / surface / substrate or by immersing the object to be cleaned in the inventive

Silicone solvent. Depending on the layer thickness and composition of the silicone residues to be removed, the exposure time can be between 10 s and several hours. In a preferred

Embodiment, the exposure time is between 30 s and 10 min. A temperature increase during the exposure time

accelerates the dissolution process. Depending on the used

Solvent C) temperatures between 20 ° C and 150 ° C can be applied, wherein as a preferred temperature range 20 ° C to 100 ° C can be specified. Likewise accelerating acts any circulation of the silicone solubilizer according to the invention, for example by pumping, shaking or by the

Action of ultrasound. In a preferred

Embodiment is the exposure time at room temperature using ultrasound between 10 s and 5 min. In a further preferred embodiment, the

Exposure time at 50 ° C - 120 ° C using

Ultrasound between 10 s and 3 min.

After the reaction time, the cleavage products are washed off with solvent without additives, which may or may not be identical to the solvent C) used in the dissolution reaction. Examples

The invention is illustrated by the following examples

illustrated without being limiting. The parts indicated are by weight unless stated otherwise. The following examples are carried out at a pressure of the surrounding atmosphere, ie at about 1000 hPa and, unless otherwise stated, at room temperature, ie about 20 ° C. In application examples for the dissolution of crosslinked silicone elastomers, the statement "exposure to ultrasound" by introducing a glass flask into a

Ultrasonic bath (Bandelin RM 40), by introducing an ultrasonic probe or the like.

Example 1: silicone-dissolving composition 1

There are 2.5 g of tetrabutylammonium fluoride and 0.05 g

Trisodium phosphate dissolved in 97.45 g of 2-octanone at room temperature by stirring within 30 min.

Example 2s silicone-dissolving composition 2

There are 2.5 g of tetrabutylammonium fluoride and 0.05 g

Disodium hydrogen phosphate in 97.45 g of 2-octanone at

Room temperature dissolved by stirring within 30 min.

Example 3s silicone-dissolving composition 3

There are 2.5 g of tetrabutylammonium fluoride and 0.05 g

Calcium hydroxide in 97.45 g of acetic acid n-propyl ester at

Room temperature dissolved by stirring within 30 min. Example 4s silicone dissolving composition 4

There are 2.5 g of tetrabutylammonium fluoride and 0.05 g

Trisodium phosphate dissolved in 97.45 g of n-propyl acetate at room temperature by stirring within 30 min.

Example 5s silicone dissolving composition 5

There are 2.5 g of tetrabutylammonium fluoride and 0.05 g

Disodium hydrogen phosphate in 97.45 g of n-propyl acetate at room temperature by stirring within 30 min.

Example 5 s silicone-dissolving composition 6

There are 2.5 g of tetrabutylammonium fluoride and 0.05 g

Calcium hydroxide dissolved in 97.45 g of 2-0ctanone at room temperature by stirring within 30 min.

Example 7: silicone dissolving composition 7 (not

Inventive)

There are dissolved 2.5 g of tetrabutylammonium fluoride 97.5 g of 2-octanone at room temperature by stirring within 30 min.

Example 8? silicone dissolving composition 8 (not

Inventive)

There are dissolved 2.5 g of tetrabutylammonium fluoride 97.5 g of n-propyl acetate at room temperature by stirring within 30 min.

Example 9; Dissolution of a polydimethylsiloxane composition

Each 1 square centimeter to a 100 thin layer of a crosslinked silicone composition (ELASTOSIL LR 3003/40 ^® of Wacker Chemie AG, Munich, Germany) are overlayed with 5 ml each of the solution of Examples 1 to 8 at room temperature. The Time to complete dissolution of the film was 10-20 seconds for each composition.

Example 10s aluminum corrosion

To assess the corrosion, in each case 1 square centimeter of a commercially available aluminum foil was placed in the solutions and removed within the test series at the indicated times. The assessment itself was done by means of

Scanning electronical recordings, wherein in Table 1 between "minus" = "-" (no visible in the SEM corrosion) and "plus" = "+" (visible visible in the SEM corrosion, ie pitting, localized dissolution of aluminum), a distinction is made.

Table 1

As is apparent from Table 1, it was surprisingly found that silicone solubilizer according to the invention are particularly peculiar to remove silicone residues at a significantly reduced aluminum corrosion. Normally it is at

Room temperature, an exposure time of a few minutes

sufficient .

Claims

claims

1. containing silicone solvent

A) at least one tetraalkylammonium fluoride,

B) at least one inorganic base capable of binding hydrogen ions, and

C) at least one solvent which is suitable for both the tetraalkylammonium A), and at least 0.001 wt. ^'% Of inorganic base B) to be solved.

2. A silicone solubilizer according to claim 1, wherein

A) 0.1-10% by weight of A),

B) 0.001-1 wt.% B),

C) represents the remainder of the 100% by weight of the silicone solubilizer.

3. The silicone solubilizer according to claim 2, wherein the component A) is selected from the group of the following tetraalkylammonium compounds:

Tetramethylammonium fluoride, tetraethylammonium fluoride,

Tetrabutylammonium fluoride, tetrapentylammonium fluoride,

Tetrahexylammonium fluoride, tetraheptylammonium fluoride,

Tetraoctylammonium fluoride, tetranonylammonium fluoride,

Tetradecylammonium fluoride, tetraisopropylammonium fluoride,

Tetraisobutylammonium fluoride, tetra (ter-butyl) ammonium fluoride, tetra (tert-pentyl) ammonium fluoride.

4. The silicone solubilizer according to claim 2, wherein component B) is selected from the group of the following inorganic salts:

Salts of phosphoric and phosphoric acids M _o H _p PO ₃ and M _o H _p PO ₄ , salts of sulfuric and sulfuric acids M _q H _r SO ₃ , M _q H _r SO ₄ , salts of nitrous and nitric acid MNO ₂ and MNO ₃ , wherein M is selected from the group of alkali and

Alkaline earth metals and monovalent cations.

5. The silicone solubilizer according to claim 2, wherein component C) is selected from the group of the following solvents:

Carboxylic acid alkyl esters, dialkyl ethers, alkyl aryl ethers, ketones.

6. A process for the preparation of the silicone solubilizer according to any one of claims 1 to 5, by intensive mixing of the components A), B) and C).

7. Use of the silicone solubilizer according to any one of claims 1 to 5, for the depolymerization and removal of crosslinked or uncrosslinked silicone residues of surfaces or substrates.