WO2013050149A1

WO2013050149A1 - Solvent stripping process for the removal of cyclic siloxanes (cyclomethicones) in silicone-based products

Info

Publication number: WO2013050149A1
Application number: PCT/EP2012/004154
Authority: WO
Inventors: Pascal Steffanut; Geraldine Primazot
Original assignee: Clariant International Ltd; Clariant Speciality Fine Chemicals France
Current assignee: Clariant International Ltd; Clariant Speciality Fine Chemicals France
Priority date: 2011-10-05
Filing date: 2012-10-04
Publication date: 2013-04-11
Anticipated expiration: 2014-04-05

Abstract

The present invention pertains to a method for the removal of cyclic siloxane residual monomers from a polysiloxane oil prepared by polymerization or by polycondensation of such cyclic siloxane monomers, whereby in a first step an organic solvent is added to the polymerization or polycondensation mixture and in a second step the residual monomers are removed together with the organic solvent by azeotropic distillation.

Description

Solvent stripping process for the removal of cyclic siloxanes (cyclomethicones) in silicone-based products

Siloxanes are used in a wide range of industrial applications, such as resins, elastomers, fuel additives, automotive polishes, waxes, and antifoaming agents, as well as in personal care products and biomedical devices. Cyclic siloxanes are the building blocks for many of these silicones polymers.

Hexamethylcyclotrisiloxane (D₃), Octamethylcyclotetrasiloxane (D₄),

decamethylcyclopentasiloxane (D₅) and dodecamethylcyclohexasiloxane (D₆) are collectively known as "volatile siloxanes".

Chemically, these siloxanes are characterized by the -Si(CH₃)₂-0- repeating unit so called "D". D₃ contains 3 of these units, D₄ contains 4 of these repeating units closed in a cycle and D₅ and D₆ respectively contain 5 and 6 of them. INCI (International Nomenclature of Cosmetic Ingredients) names are commonly used in the cosmetic and personal care industry. Blends of D₄, D₅ and D& in variable proportions are named cyclomethicones. Shampoos, conditioners and stick deodorants are the main cosmetic products in which siloxanes are used. D₄'s main use is as a monomer in the manufacturing of polymeric silicones or as dry-cleaning solvent in closed system. It also has a minor but essential use in cosmetic applications. D₅ is also used as a monomer in the manufacturing of polymeric silicones but is mainly present as solvent in cosmetic applications. Usually, these cyclic siloxanes D , D₅ and D₆ are chosen for their low toxicity, lack of skin smoothness and ease of formulation. They bring benefits to personal care products like silkiness in conditioners, volume in lip gloss and ease of application to deodorants. _.

Although siloxanes are used in many products including consumer products and have been so for many years, there is relatively little information available about their toxicity apart from the information provided by the Siloxane Research Program. However, siloxanes have generally been regarded as safe in consumer products, but new uses, e.g. in breast implants and focus on reproductive toxicity and possible endocrine disrupting effects have focussed attention on this group of substances.

As a matter of fact, these molecules were recently the focus of several

toxicological and environmental studies. In some highly industrial area, cyclic siloxanes were found at greater concentrations than linear siloxanes in sediment samples.

Of the four siloxanes mentioned in the introduction (D₃, D₄, D₅, D₆), only D₄ is on Annex I to the Substance Directive (67/548/EEC) with a health classification as toxic to reproduction in category 3. D₄ is also on the list of potential PBT and vPvB (very persistent and very bioaccumulative) substances selected on the basis of screening criteria in the EU (DEPA 2003). Subacute and subchronic toxicity studies show that the liver is the main target organ for D₄ which also induces hepatocellular enzymes. This enzyme induction contributes to the elimination of the substance from the tissues. Primary target organ for D₅ exposure by inhalation is the lung. D₅ has a similar enzyme induction profile as D₄. Preliminary results indicate that D₅ has a potential carcinogenic effect while D₄ is considered to impair fertility in rats by inhalation and is classified as a substance toxic to reproduction in category 3 with the risk phrase R62 ('Possible risk of impaired fertility').

Based on this information, the critical effects of the siloxanes are impaired fertility (D ) and potential carcinogenic effects (uterine tumours in females) (D₅).

Obviously, even if the uses of these cyclic siloxanes as monomers for silicone manufacturing are impossible to circumvent, there is a need to reduce their residual amounts in the final products. In industrial processes for polysiloxane manufacturing, these impurities are normally separated by fractional distillation. As most of these cyclic siloxanes have high boiling points (160 to 200 °C), the complete removal of these low molecular weight molecules on a commercial scale is expensive and energetically unfavourable. Additionally, high temperatures and vacuum that must be applied, lead to the formation of undesired impurities and even the so-called back-biting reaction of the polysiloxane reforming then monomeric cyclic siloxanes. Liquid- liquid extraction methods with low boiling point solvents are possible and effective but usually require dedicated technical apparatus for the separation. Moreover, flammability of these solvents may also be problematic in such process handling.

The present invention relates to a process for the removal of cyclic siloxane residual monomers from a polysiloxane oil and also to a recycling process that involves such a process.

Thus, the invention describes a method for stripping and later recycling residual cyclic siloxane monomer from a polysiloxane type polymer after the polymerization or the polycondensation step leading to this polysiloxane.

This method describes the use of specific solvents able, first, to be dissolved in the reaction mixture and in a second step, to strip the residual cyclic siloxanes from the polymer where they are brought into. These solvents are capable of forming azeotropic mixtures with the impurities that can then easily be removed by azeotropic distillation.

This stripping process is preventing the uses of high temperatures and high vacuum and then enables the formation of additional impurities during the purification step. Preferably, the solvents are organic solvents from the family of alkyl acetals of glyoxal. These solvents are produced by acetalization of glyoxal by the corresponding alcohol.

The invention is based on the surprising observation that the addition of only low amounts of these solvents followed by a mild distillation step facilitates the removal of the cyclic siloxanes still present in the polysiloxane oil after the polymerization step or introduced on purpose to the polysiloxane oil or reformed by the back-biting reaction during the polymer ageing. Consequently, the purification process of polysiloxane oils becomes more flexible, less energy-consuming, less expensive and leads to final commercial products having cyclic siloxane impurities largely under the classification requirement of 1000 ppm.

The polysiloxane oils that are purified while using this stripping process are described in the following table and formulae.

Formula (I)

CH, CH, CH₃ CH,

R2— Si— O- -Si— Si— O- Si— R2 (I)

m

CH, C R1 CH,

Formula (II)

CH₃ CH₃ CH₃

R2- Si— O- -Si— O- Si— (II) CH„ CH, CH, wherein

Ri represents the same or different monovalent Ci to C-|₈ hydrocarbon

residues optionally substituted with fluoro, chloro or bromo, hydrogen atoms, Ci to Ci₂ alkoxy or hydroxy residues, epoxy or alkylglycol residues; represents a residue of the following formula (f)

CH₂-CH₂-CH2-0-(C2H40)_U-(C₃H₆0)_V-Ro (f) in which R₀ signifies hydrogen or a Ci_-20-hydrocarbon radical, u signifies an integer not exceeding 50 and v signifies 0 or an integer not exceeding 50; represents a residue of the following formula (g)

-R^,-(NH-CH2CH2)eNR"-CH2-CHOH-CH₂-0-(C2H40)_u-(C3H₆0)_v-Ro (g), in which R' signifies a bivalent hydrocarbon radical with 1 to 8 carbon atoms, e signifies 0 or 1 and R" signifies hydrogen or a monovalent

Ci-2o-hydrocarbon radical; represents a residue of the following formula (h)

R'-(NH-CH₂CH₂)eNH-R" (h) represents a residue of the following formula (i)

in which R' signifies a bivalent hydrocarbon radical with 1 to 8 carbon atoms, e signifies 0 or 1 , R" signifies hydrogen or a monovalent

Ci-20-hydrocarbon radical and R'" represents a residue of the following formula (j)

-(C₂H40)_U-(C₃H₆0)_V-Ro 0) in which R₀ signifies hydrogen or a C _-2o-hydrocarbon radical, u signifies an integer not exceeding 50 and v signifies 0 or an integer not exceeding 50.

R₂ represents Ri and/or OH or ORi,

m has an average value of from 1 to 500 and

n has an average value of from 0 to 1500.

Examples of C C^ hydrocarbon residues Ri include alkyl residues, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, neo-pentyl, tert.-pentyl residues, hexyl residues, heptyl residues, such as n-heptyl residue, octyl residues and iso-octyl residues, such as 2,2,4-trimethylpentyl residue, nonyl residues, such as n-nonyl residue, decyl residues, such as n-decyl residue, dodecyl residues, such as n-dodecyl residue, cycloalkyi residues, such as cyclopentyl, cyclohexyl, cycloheptyl residues and methylcyclohexyl residues, aryl residues, such as phenyl and naphthyl residues, alkaryl residues, such as o-, m-, p-tolyl residues, xylyl residues and ethylphenyl residues, aralkyi residues, such as benzyl residue, a- and β-phenylethyl residue. The above hydrocarbon residues optionally contain an aliphatic double bond.

Examples thereof are alkenyl residues, such as vinyl, allyl, 5-hexen-1-yl,

E-4-hexen-l-yl, Z-4-hexen-1-yl, 2-(3-cyclohexenyl)ethyl and cyclododeca-4,8- dienyl residues. Preferred residues with an aliphatic double bond are the vinyl, allyl and 5-hexen-1-yl residues.

Examples of C₁-C18 hydrocarbon residues substituted with fluorine, chlorine or bromine atoms include the 3,3,3-trifluoro-n-propyl residue, the

2,2,2,2',2^,,2'-hexafluoroisopropyl residue, the heptafluoroisopropyl residue and the 0-, m- and p-chlorophenyl residues.

Examples of amino containing residues R1 include amino-propyl amino-ethyl

(CH₂-CH2-CH2-NH-CH₂-CH2-NH₂) residue or aminopropyl (CH₂-CH₂-CH₂-NH₂) residue.

Examples of Ci-Ci₈ hydrocarbon residues R₂ are saturated linear or branched- chain or cyclic alkyl residues, such as methyl and ethyl residues as well as propyl, butyl, pentyl, hexyl, 2-methylpropyl, cyclohexyl and octadecyl residues, alkyl residues bonded through an oxygen atom or hydroxy residue. All the examples stated for alkyl residues also apply to alkoxy residues.

Examples of amino containing residues R2 include amino-propyl amino-ethyl

(CH2-CH2-CH2-NH-CH2-CH2-NH2) residue or aminopropyl (CH₂-CH₂-CH2-NH₂) residue.

The acetals that are used while using this stripping process are belonging to the following formula (III).

R4— O O— R4

\ /

HC— CH (III)

/ \

R3— O O— R3 wherein

R3 and R4 may be equal or different from each other and stay for a Ci to Cis

linear or branched hydrocarbon residue or for a cyclic

hydrocarbon.

Examples of C1-C18 hydrocarbon residues R3 and R4 include alkyl residues, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, neo-pentyl, tert.-pentyl residues or hexyl residues. Preferably

R3 and R4 stay for a Ci to Cis linear hydrocarbon residue

Most preferably

R3 and R4 are equal and stay for a Ci to C₂ hydrocarbon residue.

The polyorganosiloxanes of the formula (I) or (II) that are purified by stripping may be characterized by typical parameters which are customary per se, for example by their average molecular weight and the content of amine nitrogen, and also by their viscosity. The average molecular weight of the polyorganosiloxanes of the formula (I) or (II) can vary in broad ranges. The average molecular weight of the included aminopolyorganosiloxanes and their amine value can vary in broad ranges

The polyorganosiloxanes of the formula (I) or (II) advantageously have a viscosity in the range of from 30 to 30,000, principally 30 to 20,000, preferably 30 to 10000 cP (Brookfield rotational viscometer RV, spindle No. 5, at 20 °C). The polyorganosiloxanes of the formula (I) or (II) having an amine functionality may have an amine number in the range from 0.05 to 5. The amine number (the concentration of amine in mmol per gram also called AZ in our examples) is determined by a potentiometric titration comprising neutralization of amine functions by perchloric acid in an acid environment. Protocol: In a 150 ml beaker, between 0.2 g and 1 g of the amino-siloxane oil are weighed. 50 ml of THF are added to solubilize the oil and 50 ml of acetic acid are also added to make an acid environment. The mixture is stirred for

homogenization and thereafter titrated by perchloric acid 0.1 M in acetic acid.

Results: The amine function concentration (AZ) is determinated by the following formula

AZ = [V_Hcio₄ x 0.1]/m wherein

VHCIO4 equivalent volume of HCI0₄ (ml) and

m weight of oil introduced in the beaker (g) is.

The polyorganosiloxanes of the formula (I) or (II) may be produced in a manner known per se or analogously to known methods, for example by hydrosilylation reaction on Si-bonded hydrogen atoms, by aminoalkylation of polysiloxanes containing reactive Si-bonded hydrogen atoms, or principally by copolymerization of various functional silanes with corresponding nonionogenic silanes or

polysiloxanes or cyclic siloxanes.

The present invention is in still another respect a process for recovering a cyclic siloxane monomer from a crude reaction solution removing a mixture of vaporized solvent and cyclic siloxane monomer and then separating the cyclic siloxane from the solvent.

This process is a cost-effective, efficient method for recovering the cyclic siloxane monomers from a crude reaction solution. Because of this, subsequent high temperature distillation steps can be reduced or avoided. The process can also produce polysiloxane polymer of formula (I) and (II) having low levels of impurities, and in particular low levels of low molecular weights siloxanes.

The present process starts with a crude reaction solution containing the

polysiloxane polymer (as described more fully below), a solvent and reaction by- products of cyclic siloxane types, the nature of which will depend on the particular process that is used. The selection of solvent is determined by the particular starting monomer Particularely suitable solvents from the acetal family include tetraethoxyethane (so-called TEE, Highsolv^® E99 from Clariant) or tetramethoxyethane (so-called TME, Highsolv P99 also from Clariant) but should not be limited to both examples.

Preferred solvents from the acetal family have boiling temperatures (at

atmospheric pressure) between 130 °C and 200 °C, may be substantially immiscible or miscible in water. Especially preferred solvents from the acetal family are less volatile than water, and are thus allowing first the easy removal from water from the reaction mixture. Two especially preferred solvents are TME and TEE.

The crude reaction solution is heated to drive off solvent. As the solvent is removed, the cyclic siloxane monomer is removed together with. The solvent is completely removed from the polymer mixture and preferably the amount of solvent, in weight per reaction mixture weight, needed to bring the cyclic siloxanes under the 1000 ppm limit is between 0.25 % to 15 % by weight of solvent, preferably between 1 % to 10 % by weight of solvent.

Specific Method

The linear and unfunctionalised polysiloxane oils are commercially purchased and analysed by GC to determine their initial contents in cyclic impurities.

The linear and PEG or alkyl functionalised polysiloxane oils are commercially purchased and analysed by GC to determine their initial contents in cyclic impurities.

The amino functionalised oils are manufactured following the two examples S1 and S2 described herein-below and analyzed to determine their initial content in cyclic impurities. A batch made following the invention uses a stirred reactor that contains a mixture of poylsiloxane polymeric material and starting material like cyclic siloxanes as residual impurities (introduced on purpose or present from the synthetical process). A short distillation column as outlet is provided for removing volatilized solvent and impurities from the reactor. The liquid polysiloxane/solvent mixture liquid is stirred using an agitator blade, and heated to the desired volatilization temperature. If desired, a slight vacuum is provided in the head space. The solvent/impurities mixture is then distillate until completion (no distillate flow visible). The analysis if the cyclic siloxanes in the polysiloxane oil are performed at the end of the distillate and compared to the initial value.

For the copolymerization, the amino functionalised silanes are preferably copolymerized with cyclic siloxanes, for example hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,

dodecamethylcyclohexasiloxane and technical-grade mixtures of two or more thereof.

The copolymerization may be carried out in a manner known per se, principally by reaction of the reactants at moderate or elevated temperature, optionally under reduced pressure, in particular at temperatures in the range 15 to 180 °C, optionally in the presence of a catalyst and if desired with use of end-blocking groups, for example with hexamethyldisiloxane. As catalysts, use can be made of acids (in particular formic acid, acetic acid, sulphuric acid, acidic ion exchangers or trifluoromethanesulphonic acid) or of alkali metal or ammonium compounds, for example alkali metal or ammonium silanolates (for example potassium silanolate or tetramethylammonium silanolate) or alkali metal hydroxides or ammonium hydroxides, which form the corresponding silanolates in situ with the respective silanes, or else alkali metal hydroxides, carbonates or bicarbonates (for example potassium hydroxide, sodium hydroxide or sodium bicarbonate) or further benzyltrimethylammonium hydroxide or tetrabutylammonium hydroxide. Illustrative examples : Production of amino-modified siloxanes of formula (1)

EXAMPLE 1 . S(1)

0.95 part of tetrabutylammonium hydroxide (40 % methanolic solution) is added to 951.76 parts of octamethylcyclotetrasiloxane and 38.31 parts of

[N-(2-aminoethyl)-3-amino-propyl]methyldimethoxysilane, and the mixture is heated to 70 °C over the course of 90 minutes under a gentle stream of nitrogen. After 2 hours at 70 °C, evacuation is carried out to a residual pressure of 50 mbar and subsequently the mixture is heated to 110 °C at a constant residual pressure. After one hour at 110 °C and 50 mbar, the mixture is cooled to room temperature under reduced pressure. About 965.00 parts of amino-modified

polydimethylsiloxane S(1) having an amine number of about 0.385 are obtained.

EXAMPLE 2: S(2)

The procedure is as for the production of S(1), but 1600.00 parts of

octamethylcyclotetrasiloxane are reacted with 93.00 parts of

[N-(2-aminoethyl)-3-aminopropyl]methyldimethoxysilane and with 4.80 parts of tetrabutylammonium hydroxide (40 % methanolic solution). About 1646.6 parts of amino-modified polydimethylsiloxane S(2) having an amine number of about 0.55 are obtained.

Depending on the production conditions and the raw material selected, the functional groups may be randomly distributed or may be terminal or may be grouped as in block polymers or may also accumulate towards the extremities of the linear chains.

Examples according to the invention: Stripping of cyclic impurities from siloxane oils

When cyclic impurities are present in the purchased or synthesised product : In a typical experiment, 200 grams of a silicone oil from the general formula (I) or (II) (synthesised or purchased from commercial sources) are mixed with 8 grams of tetramethoxyethane (TME, Highsolv^® P99). The reaction mixture is then heated to 155 °C at ambient pressure and this temperature is maintained until no more distillate is flowing from the condenser. The remaining polysiloxane oil is analysed by GC to determine the level of cyclic siloxanes impurities.

When cyclic impurities are introduced to purchased or synthesised product :

In another experiment, 200 grams of a silicone oil from the formula I or II and without cyclic impurities are admixed with a known quantity (for example 5 grams) of D₄. 8 grams of tetramethoxyethane (TME, Highsolv^® P99) are introduced and the reaction mixture is then heated to 155 °C. This temperature is maintained until 13 grams of product is distilled off. The polysiloxane oil is then analysed by GC to determine the level of cyclic siloxanes impurities remaining.

Compound A

Compound B

Compound C

Compound D

CH₃ CH₃ CH₃ CH,

H₃C- Si— -Si— Si— O- Si— CH,

m

CH, CH, CH₂ CH, CH₂ CH

Compound E

Compound F

†H₃ CH,

H₃C- -Si— O O- ^■Si— C

m CH, CH,

Compound G

Compound H

CH₃ CH₃ CH 3 CH,

H₃C- Si— O- -Si— 0 Si— O- Si— CH,

m

CH„ CH, ^C8^H17 CH,

Compound I

CH, CH CH₃ CH

HO— Si— O- -Si— Si— O- Si— OH

m

CH, CH, CH₂ CH₃

CH,

H,

CH,

L^C O^

Compound J

The abbreviations used in the table herein-below have the following meaning: D_x stands for the cyclic siloxane introduced and/or followed by analytical method. The cyclic siloxanes may be present by incidence (product degradation) or have been introduced on purpose (monomer for the polymerization process). [Dx] before stands for the concentration in (ppm) of the cyclic siloxane introduced and/or followed by analytical method before the treatment with stripping solvents.

[Dx] after stands for the concentration in (ppm) of the cyclic siloxane introduced and/or followed by analytical method after the treatment with stripping solvents.

[AZ] in mmol/g stands for the concentration in amine functionality evaluated by acidimetric dosage.

In the following example, A is a typical polysiloxane oil terminated with OH groups and originally containing 40200 ppm of D4 (introduced on purpose). AZ number is zero mmol/g. This product is stripped with TME and after the treatment, the residual amount of D4 is 930 ppm. A' is the same polysiloxane oil containing D5 (introduced on purpose) and stripped this time by TEE. The residual amount of D5 is 780 ppm.

Table 1

Compound Dx solvent [Dx] [Dx] [AZ]

before after mmol/g

A D₄ TME 40200 930

A' D₅ TEE 35000 780

B D₄ TME 12300 350

B' D₅ TEE 34700 600

C D₄ TME 14100 420 0.1

D D₄ TME 25000 710 0.1 D' D₅ TEE 25000 980 0.1

E D₄ TME 18700 650 0.3

F D₄ TME 24500 800 0.5

G D₄ TME 17000 500

H D₄ TME 8200 250

I D₄ TME 10100 450

J D₄ TME 35200 740

With the stripping method according to the instant invention, cyclic impurities are removed from the polysiloxane oils at temperatures below the boiling point of the cyclic impurities and at atmospheric pressure. This process is easy to apply and doesn't require the use of aromatic and/or toxic solvents. The acetals used for the stripping process have no influence on the groups present on the silicone backbone and don't change the final coloration of the purified oils. The obtained products are found after analysis under the limit of 1000 ppm of D₄ impurity. The stripping process described in this invention is preventing the future toxicological classification of the silicone oils by removing the most problematic cyclic impurities from the product.

Claims

Patent claims

1. Method for the removal of cyclic siloxane residual monomers from a polysiloxane oil prepared by polymerization or by polycondensation of such cyclic siloxane monomers, whereby in a first step an organic solvent is added to the polymerization or polycondensation mixture and in a second step the residual monomers are removed together with the organic solvent by azeotropic distillation.

2. Method according to claim 1 , whereby the organic solvent added to the polymerization or polycondensation mixture is a solvent capable to be dissolved in the polymerization or polycondensation mixture in a first step and to strip the residual cyclic siloxanes from the polysiloxane oil by azeotropic distillation.

3. Method according to claim 1 or claim 2, whereby the organic solvents are alkyl acetals of glyoxal produced by acetalization of glyoxal with alcohols.

4. Method according to any of claims 1 to 3, whereby the alkyl acetals of glyoxal have a boiling temperature (at atmospheric pressure) between 130 and 200 °C and are immiscible or miscible in water.

5. Method according to any of claims 1 to 4, whereby the alkyl acetals of glyoxal are less volatile than water.

6. Method according to any one of claims 1 to 5, whereby the alkyl acetals of glyoxal are selected from tetraethoxyethane or tetramethoxyethane.

7. Method according to any one of claims 1 to 6, whereby the organic solvent is added in an amount of from 0.25 to 15 wt.-% of solvent, preferably from 1 to 10 wt.-% of solvent, calculated per total weight of the polymerization or

polycondensation mixture.

8. Method according to any one of claims 1 to 7, whereby the azeotropic distillation is performed under a maximum temperature of 160 °C and under atmospheric pressure.

9. Method according to any one of claims 1 to 8, whereby polysiloxane oils are purified having the following general formulae:

Formula (I)

ChL CH₃ CH₃ ChL

R2— Si— 0- Si— Si— O- Si— R2 (I)

m

ChL ChL R1 CH,

Formula (II)

CH₃ CH₃ ChL

R2- Si— O- -Si— O- Si— R2 (II) ChL CH, ChL wherein

Ri represents the same or different monovalent Ci to C-is hydrocarbon

residues optionally substituted with fluoro, chloro or bromo, hydrogen atoms, Ci to C12 alkoxy or hydroxy residues, epoxy or alkylglycol residues; represents a residue of the following formula (f)

CH₂-CH₂-CH2-0-(C2H40)_u-(C3H₆O)v-Ro (f) in which Ro signifies hydrogen or a Ci-2o-hydrocarbon radical, u signifies an integer not exceeding 50 and v signifies 0 or an integer not exceeding 50; represents a residue of the following formula (g)

-R^,-(NH-CH₂CH2)eNR"-CH2-CHOH-CH2-0-(C₂H40)_u-(C₃H60)_v-Ro (g), in which R' signifies a bivalent hydrocarbon radical with 1 to 8 carbon atoms, e signifies 0 or 1 and R" signifies hydrogen or a monovalent

Ci-2o-hydrocarbon radical;

represents a residue of the following formula (h)

R^,-(NH-CH₂CH₂)eNH-R" (h) represents a residue of the following formula (i)

-R'-(0-CH2-CH(OH)-CH2)eNR^,,R'" (i) in which R' signifies a bivalent hydrocarbon radical with 1 to 8 carbon atoms, e signifies 0 or 1 , R" signifies hydrogen or a monovalent

Ci-2o-hydrocarbon radical and R'" represents a residue of the following formula (j)

-(C₂H₄0)_u-(C₃H₆CVRo (j) in which Ro signifies hydrogen or a Ci^o-hydrocarbon radical, u signifies an integer not exceeding 50 and v signifies 0 or an integer not exceeding 50. represents Ri and/or OH or ORi,

has an average value of from 1 to 500 and

has an average value of from 10 to 1500.

10. Method according to any of claims 1 to 9, whereby polyorganosiloxane oils of the formula (I) or (II) have a viscosity in the range of from 30 to 30,000, preferably from 30 to 20,000, more preferred from 30 to 10,000 cP, determined with a Brookfield rotational viscometer RV, spindle No. 5, at a temperature of 20 °C.

11. Method according to any one of claims 1 to 9, whereby the

polyorganosiloxane oils of the formula (I) or (II) have an amine functionality and an amine number (AZ) in the range from 0.05 to 5, determined by potentiometric titration comprising neutralization of amine functions by perchloric acid in an acid environment.

12. Polysiloxane oil prepared by polymerization or by polycondensation of cyclic siloxane monomers, whereby the polysiloxane oil is treated by a method according to any one of claims 1 to 11 and comprises residual D₄ impurity under the limit of 1000 ppm.