FR2624867A1 - PROCESS FOR PREPARING A POLYORGANOSILOXANE EMULSION AND OIL CONCENTRATE FOR USE IN THIS PROCESS - Google Patents

Abstract

The invention relates to a process for preparing an oil-in-water type emulsion of a polyorganosiloxane, the molecule of which contains at least one polar group attached to silicon by an SiC bond or at least one silanol group, which comprises forming a translucent or transparent oil concentrate by mixing 1 the polyorganosiloxane, 2 one or more surfactants chosen from ethoxylated alcohols, ethoxylated alkylphenols, ethoxylated fatty acids and ethoxylated fatty acid esters, 3 of water and 4 an aliphatic monoalcohol having 5 to 18 carbon atoms, the amount of water being sufficient to produce a transparent or translucent oil concentrate, and B to rapidly disperse the concentrate in water. The emulsion obtained offers great storage stability. Applications: those of silicone emulsions, in particular: antifoam agents, water repellency for textiles, mold release agents, cosmetics, etc.

Description

The present invention relates to aqueous emulsions of

  polyorganosiloxanes and in particular relates to a process for preparing such emulsions in

  which the average size of the polyorga-

  nosiloxane in emulsified form is less than

  0.3 micrometer. The invention also relates to a concen-

  very which includes a polyorganosiloxane oil and an agent

  surfactant and which is useful in the above process.

  Polyorganosiloxane emulsions have been known for many years and are widely used in applications such as defoamers, the treatment of textiles to make them water-repellent or to give them a flexible hand, release agents and personal care products, for example example hand lotions. These emulsions typically contain a polyorganosiloxane, water

  and one or more surfactants and they present

  have an opaque, milky appearance, which results from

  of the globules of the oily phase and of the different

  rence of refractive index between the oily and aqueous phases. The relatively large size of the globules makes these emulsions subject to phase separation

  oily and watery during storage. It is possible

  ble to make the emulsion translucent and improve its

  storage stability using a large pro-

  portion of water compared to the oily phase. Such a

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  however, this involves the storage and transport of large volumes of water and is therefore not

  commercially attractive.

  It has been shown in British Patent No. 1,441,424 that transparent emulsions (called "microemulsions") of organosilicon compounds can be prepared if a surfactant is used which comprises, in specified proportions, (a) at least an n-alkyl monoether of a polyethylene glycol, (b) a sodium dialkylsulfosuccinate, (c) at least one

  acid chosen from oleic, linoleic, lininic

  lenic and ricinoleic, and (d) at least one amine

  chosen between triethanolamine and N-hydroxyethyl-

  morpholine. More recently, it has been proposed, in the

  European Patent Application No. 138,192, to prepare certain

  microorganosiloxane micro-emulsions by a process which, briefly described, consists in mixing a polyorganosiloxane and a surfactant, adding water to the mixture to form an oily concentrate

  translucent, then rapidly dispersing said concentration

  very oily translucent in water to form an emulsion in which the average size of the polyorganosiloxane globules is less than

About 0.3 micrometer.

  Although the process of European patent application No. 138 192 can be successfully used to prepare stable microemulsions, it has been

  found that, from time to time, the stability of the emul-

  Zion is less than expected. Although the precise cause of this phenomenon has not been determined, it is believed that this is the effect of small variations affecting, from one batch to another, the nature or the purity of the raw materials of the trade, for example surfactants used in the manufacture of

  emulsions. In such a case, a possible remedy consists

  would be to select the finished emulsions or the

  raw materials before acceptance and use.

  However, such a procedure leads to a waste of materials and involves a lot of testing.

that take time.

  The Applicant has now discovered with

  surprise that stable microemulsions containing certain

  any type of surfactant can be made by modifying the patent application process

  European No. 138 192. The said modification offers the advantage

  tage to be easily implemented and avoids inconvenience

  benefits associated with selection and testing operations

mentioned above.

  According to the present invention, there is provided a

  process for preparing an oil-in-type emulsion

  water of a polyorganosiloxane, which consists

  (A) to form a translucent or transparent oil concentrate

  parent comprising (1) a polyorganosiloxane which has at least one polar group attached to silicon by an ESic bond and / or at least one silanol group and which is liquid at the mixing temperature; (2) one or more surfactants chosen from ethoxylated alcohols, ethoxylated alkylphenols, ethoxylated fatty acids and esters of ethoxylated fatty acids, at least one of said surfactants being insoluble in polyorganosiloxane (1) mixture;

  (3) sufficient water to pro-

  coat a translucent or transparent oil concentrate; and

  (B) rapidly dispersing the concentrated trans-

  lucid or transparent of (A) in water so as to form an emulsion of polyorganosiloxane of the oil-in-water type where the average size of the polyorganosiloxane globules present in the emulsion is less than 0.3 micrometer, characterized in that the oil concentrate also comprises (4) an aliphatic monoalcohol of 5 to

18 atoms. of carbon.

  Polyorganosiloxanes (1) which can be emulsified according to the process of the present invention

  contain at least one polar group attached to silicon

  cium by a bond of silicon to carbon. Examples of polar groups which may be present in the polyorganosiloxane are organic groups carrying as substituents groups such as amine groups,

  amine salt, amide, carboxylic, carboxylic acid salt

  as, carbinol, phenolic, sulfonate and sulfate. We can

  also use polyorganosiloxanes which contain

  one or more silanol groups (SiOH), with or without the additional presence of organic groups

polar.

  Polyorganosiloxanes (1) can be defi-

  nis like those which contain at least one motif of general formula RaQSio3 (a) to 3-a (a)

2

  wherein each R represents a monovalent hydrocarbon group or a non-polar substituted monovalent substituted hydrocarbon group, Q represents a polar monovalent organic group attached to silicon by an SiC bond, or a hydroxyl group, and the value of a is 1 or 2, all

  other motifs possibly present in the polyorgano-

  siloxane being of those represented by the general formula R'bSi04_ R'bSio 4-b (b) in which each R 'is as defined above for R and b is 1, 2 or 3. In the general formulas (a ) and (b), each R and each R 'can be, for example,

  an alkyl group such as methyl, ethyl, butyl, cyclo

  hexyl, n-octyl, trimethylphenyl, decyl and octadecyl, an alkenyl group such as vinyl, allyl, hexenyl and cyclohexenyl, an aryl, alkaryl or aralkyl group such as phenyl, naphthyl, tolyl, benzyl and 2-phenylethyl, or a hydrocarbon group substituted such as chloropropyl,

  3,3,3-trifluoropropyl, chlorophenyl and mercaptopropyl.

  For most applications, it is preferable that the groups R and R 'are those which have less than 8 carbon atoms. At best, at least 50% of the total R and R 'groups are methyl groups and any groups which may remain are vinyl and / or phenyl groups. When group Q is a group

  polar organic, it can be represented by the form

  mule -R "X in which R" represents a divalent organic bonding group attached to silicon by an SiC bond and X represents a polar radical. The group R ″ can be composed only of carbon atoms and hydrogen atoms or of carbon atoms, hydrogen and hetero atoms,

  for example oxygen or sulfur, interrupting or ter-

  undermining a carbon chain. Examples of R "groups are - (CH2) 3 -, (CH2) 4-, -CH2CH.CH3CH2-, -OCH2CH2-, - (CH2) 3OCH2 -, - (CH2) 2C6H4CH2- and

- (CH2) 3CSCH2CH2-.

  When the polyorganosiloxane has a

  amine functionality, the polar radical X is preferably

  rence that represented by the general formula -NH in which R2 represents H, an alkyl group having 1 to 4 carbon atoms, CH2CH2NH2, - (CH2) 4NH2 or

  -CH2CH2NHCH2CH2NH2. The radical X can also represent

  ter a salt of the amine, for example a carboxylate or a

halide.

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  The substituent X can also represent other polar groups, for example carbinol -O (C2H4O) x (C3H60) yH ox and y can each be zero or an integer, carboxyl -COOH or carboxylic salt, for example -COONa or - COOK, and phenol, for example

-C6H40H or -C6H3CH OH.

-6H4H 6 3 3

  Particularly good polyorganosiloxanes

  suitable for emulsification according to the process of the pre-

  sente invention are those in which the polar group comprises at least one amido substituent, that is to say in which X is a radical such that

O O

4 "3" 4

-NR CR or -CNR 2

  or R represents an alkyl group having 1 to 6 atoms.

  carbon and each R4 represents hydrogen, an alkyl group having 1 to 4 carbon atoms or the group O ". 3

  -CH2CH2NHCR. Particular examples of radicals -

O- 0 0

  amides X are -N (CCH3) CH2CH2NH (CCH3) and -NHCH2CH2NH (CCH3).

  In the latter case, the polar group R "X can be

  considered either to contain both the functional-

  amino and amido lites, either as an amido-functional polar group in which the carbon chain of

  linking group R "is interrupted by a heteroatom (N).

  The polyorganosiloxanes can be homopoly-

  mothers, that is to say composed only of units (a), or copolymers, that is to say composed of units (a) and of units (b), as long as they are liquid at temperature o they are mixed with the surfactant. Thus, the polar groups (Q) can be attached to terminal or non-terminal Si atoms in the molecule,

  or they may be present in both of these situations.

  The polyorganosiloxanes can be branched, liquid homopolymers and copolymers, but they are preferably so-called linear polyorganosiloxanes, that is to say those in which the ratio of organic substituents to silicon atoms is around 2, generally around 1.9 to about 2.3. For economic considerations, it is also preferable for the polyorganosiloxanes to be copolymers in which the units (a) do not constitute more than approximately 30% of the total units (a) and (b) of the copolymer, and constitute preferably 0.5% to 10%. The preferred polydiorganosiloxanes can be represented by the general formula R (3_p) QpSi (R'2SiO) q (RQSiO) rSiQsR (3_s)

  in which R, R 'and Q are as defined above

  ment and p and s are each 0 or 1. The values of each of g and r can range from zero to 800 or more, provided that the sum p + r + s is at least 1 and the

  resulting polyorganosiloxane either a liquid at room temperature

  the mixture is made. To facilitate the disper-

  sion of the oil in water concentrate, it is preferable that the sum g + r has a value less than 600. It is also advantageous from the economic point of view to keep the proportion of polar substituents to a minimum compatible with the obtaining the desired effect when using the emulsion. In general, therefore, the value of r should preferably not exceed 30% of

  g + r and, preferably still, should be held in the in-

tervalle going from q + r to q + r

400 10

  Polyorganosiloxanes that do not contain

  no polar groups can be emulsified by pre-

  sence of polyorganosiloxanes containing polar groups

  res by the method of the present invention. All these possible non-polar polyorganosiloxanes must be incorporated into the emulsion at the same time as the polar organosiloxane and should preferably not exceed 30%

  weight of the total polyorganosiloxane used.

  As the surfactant (2), one or more surfactants may be used chosen from ethoxylated alcohols, ethoxylated alkylphenols, ethoxylated fatty acids and ethoxylated fatty acid esters. At least one of the above-mentioned surfactants must be insoluble in the polyorganosiloxane. European Patent Application No. 138,192 explains the method to be followed in determining insolubility and choosing the

  suitable surfactants for use with poly-

  polar organosiloxanes. Examples of surfactants

  active ingredients are ethoxylated lauryl alcohol, ethoxylated tridecanol, ethoxylated stearyl alcohol, ethoxylated C12 to C15 secondary alcohols, ether

  polyethylene glycol trimethylnonyl, nonylphenol

  ethoxylated nol, ethoxylated octylphenol, ethoxylated dodecylphenol, ethoxylated stearylphenol, ethoxylated stearic acid, ethoxylated lauric acid, ethoxylated sorbitan mnionolaurate and sorbitan monopalmitate. These surfactants are well known substances and are generally available commercially under the trademarks Triton, Tergitol,

  Trycol and Dobanol. They can be obtained by condensing

  tion of alcohols, acids, alkylphenols or suitable esters

  required with ethylene oxide or polyethylene glycols and may contain varying amounts of units

  ethylene oxide, usually about 2 to about 30.

  The proportion of surfactant (s) that is needed

  to obtain the size of the cells and the stability

  desired for the emulsion differs depending on the nature of the poly-

  organosiloxane and surfactants themselves.

  In general, the proportion of surfactant required is greater the smaller the size of the globules. Usually the surfactant is used in an amount of 10 to 200 parts by weight, preferably 20 to 50 parts, per 100 parts by weight of polyorganosiloxane.

  The aliphatic monoalcohols which are used.

  in the process of the present invention are those which have 5 to 18 carbon atoms. Although the spirits

  the lowest in this class, for example the pen-

  tanol and hexanol, are effective to some degree

  to stabilize microemulsions, the best results

  tats were obtained with higher alcohols, in part

  especially those with 8 to 16 carbon atoms. Alcohols are effective in relatively small amounts

  and they are preferably used in proportions of approx.

  0.1 to 5% by weight relative to the weight of the polyorgano-

  siloxane. It is possible to use more than 5% if this

  is desired, but it is not thought to result in any advance

  tage of employment of these higher proportions.

  The process of the present invention is practiced by first forming the oil concentrate, i.e. by mixing the polyorganosiloxane, one or more of the specified surfactants, the alcohol and sufficient water to make the mixture translucent or transparent. It is better to mix the polyorganosiloxane, the surfactant and the alcohol first, then

  add enough water to obtain the transluc-

  the desired transparency or transparency of the concentrate. Once the proportion of water required for a particular combination of polyorganosiloxane, agent has been established

  surfactant and alcohol, the concentrate can be easy-

  prepared by simply mixing the components.

  As a general indication, the amount of water required to produce translucency or transparency varies between about 4 and about 40 parts by weight per parts by weight of polyorganosiloxane. Translucent or transparent oil concentrates comprising components (1), (2), (3) and (4) are included in the frame

of the present invention.

  Step (B) of the process of the invention consists in rapidly dispersing the oil concentrate in

  the water. This second step can be performed immediately-

  following step (A). In many cases, any-

  times, we will see that the concentrate is stable at the

  laying for periods ranging from a few days to several months. In these cases, the execution of step (B) can be postponed as desired. For the preparation

  small amounts of the final microemulsion, the

  Fast persion required can be achieved by shaking or other manual means. However, for

  large volume production, it is best to

  use mechanical means of dispersion, for example mixers, colloid mills and agitators

  mechanically actuated, by which emulsions can

  can be prepared in a continuous process or in batches. British Patent No. 1,441,424 referred to above reveals that the haze which can be created when the surfactant / organosilicon mixture is emulsified in water can be eliminated by the addition of successive portions of an alkanol. as the emulsification progresses. In the process of the present invention, it is necessary that the alkanol is

  present in the concentrate before the final emulsifying step

  if you want to obtain the desired stability of the emulsion. The microemulsions of the present invention can be used in any of the known applications for more conventional emulsions, for example as textile treatment products and mold release agent, and in personal care applications such as the formulation of

  protective lotions and cosmetic products.

  The following nonlimiting examples illus-

  trent the present invention. In these examples, all

  the parts are expressed by weight.

Example 1

  The following ingredients are introduced into a 100 ml glass container: Amide-functional polyorganosiloxane * 15 parts C11-C14 ethoxylated secondary alcohol 6 parts (7 ethoxy groups) C1l-C14 ethoxylated secondary alcohol 3 parts (5 ethoxy groups) 1-tridecanol 0.25 part * The amide-functional polyorganosiloxane is a polydimethylsiloxane blocked at the ends by trimethylsiloxy units, containing 2 mole percent of units of formula (MeSio)

CH CHCH NCH CH NH

2r 2w2 2,

CH3 C = O C = O

l l

CH3 CH3

  and having a viscosity of 650 mPa.s at 25 C.

  The ingredients are mixed well by hand and, to the resulting opaque mixture, 5.8 parts of water are then added, with stirring, to obtain a transparent viscous composition (limpid like water). New additions of 10.5 parts of water are carried out, then 57.7 parts of water, the mixture being well stirred after each addition. A translucent microemulsion is obtained which is stable for more than 3 months and

  which contains about 15% by weight of polyorganosiloxane.

  Two other compositions are prepared in an analogous manner using the same ingredients,

  same proportions, except that in one case we omit the tride-

  canol and in the other case it is added after the formation of the final emulsion. In each case, a translucent microemulsion is obtained, but which begins to separate

  in oil and water phases after less than 24 hours.

Example 2

  A microemulsion is prepared by proceeding as described in Example 1, except that the tridecanol is replaced by the same amount of n-pentanol. The emulsion is stable for about 2 days. This period is longer than that obtained when pentanol is omitted, but much shorter than that of the emulsion

  obtained using tridecanol.

  Example 3 The procedure of Example 1 is repeated,

  except that the tridecanol is replaced by an equal

  Dobanol 23 (a synthetic alcohol C12-C13).

  A translucent emulsion is obtained which is stable

for more than 3 months.

Claims (5)

  1. Process for preparing an oil-in-water type emulsion of a polyorganosiloxane, which consists   (A) to form a translucent or transparent oil concentrate   parent comprising (1) a polyorganosiloxane which has at least one polar group attached to silicon by an ESiC bond and / or at least one silanol group and which is liquid at the mixed temperature; (2) one or more surfactants chosen from ethoxylated alcohols, ethoxylated alkylphenols, ethoxylated fatty acids and ethoxylated fatty acid esters, at least one of said surfactants being insoluble in the polyorganosiloxane (1) mixture;   (3) sufficient water to pro-   coat a translucent or transparent oil concentrate parent; and   (B) rapidly dispersing the concentrated trans-   lucid or transparent of (A) in water to form an emulsion of polyorganosiloxane of the oil-in-water type where the average size of the polyorganosiloxane globules present in the emulsion is less than 0.3 micrometer, characterized in that that the oil concentrate also comprises (4) an aliphatic monoalcohol containing 5 to 18 carbon atoms.   2. Method according to claim 1, character-   laughed in that the aliphatic monoalcohol (4) has 8 to 16 carbon atoms.   3. Method according to claim 1 or 2,   characterized in that the polar group of the polyorganosi-   loxane comprises at least one substituent of the amido type.   4. Translucent or transparent oil concentrate comprising (1) a liquid polyorganosiloxane which has at least one polar group attached to silicon by an ESiC bond and / or at least one silanol group, (2) one or more surfactants chosen from ethoxylated alcohols, ethoxylated alkylphenols, ethoxylated fatty acids and ethoxylated fatty acid esters, at least one of said surfactants being insoluble in polyorganosiloxane (1), - and (3) of water, characterized   in that it also contains (4) an alipha monoalcohol-   tick with 5 to 18 carbon atoms.   5. Translucent or transparent oil concentrate   rent according to claim 4, characterized in that the alcohol (4) is present in a proportion of 0.1 to 5%   by weight relative to the weight of the polyorganosiloxane.