WO1996010599A1

WO1996010599A1 - Process for producing stabilised aqueous polyolefine wax dispersions

Info

Publication number: WO1996010599A1
Application number: PCT/EP1995/003796
Authority: WO
Inventors: Antoni Soler Codina
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1994-10-04
Filing date: 1995-09-25
Publication date: 1996-04-11
Also published as: DE4435404A1

Abstract

Stabilised aqueous polyolefine wax dispersions can be produced by (a) producing an aqueous solution of an acid tenside dispersant and finely divided polyolefine wax and (b) subsequently neutralising the dispersion by the addition of alkaline hydroxides above the melting point of the wax.

Description

Process for the preparation of stabilized aqueous polyolefin wax dispersions

Field of the Invention

The invention relates to a process for the preparation of stabilized aqueous polyolefin wax dispersions, in which aqueous dispersions composed of a polyolefin wax and an acidic surfactant dispersant are neutralized at elevated temperature and, if appropriate, elevated pressure.

State of the art

Polymers based on ethylene and / or propylene with an average molecular weight in the range from 500 to 20,000 have a waxy character. Aqueous dispersions of these polyolefin waxes have therefore long been used as a replacement for natural wax emulsions and are used, for example, for sealing hard surfaces, for textile finishing or as defoamers.

A problem in the production of these polyolefin wax dispersions is that of producing finely divided dispersions. len that are stable over a long period of time and do not sediment. One way to improve the dispersibility of the polyolefins is by oxidative surface treatment of the polymers. This oxidizes methyl to carboxyl groups and increases the polarity of the waxes. Usually, however, the polyolefins are stirred into the aqueous solution of a surfactant dispersant, preferably an alkyl phosphate, and heated above the melting point. The dispersions accessible in this way are sufficiently fine-particle, but do not always have satisfactory storage stability.

The object of the invention was therefore to provide an improved process for the production of finely divided aqueous polyolefin wax dispersions with improved storage stability.

Description of the invention

The invention relates to a process for the preparation of stabilized aqueous polyolefin wax dispersions, in which

(a) produces an aqueous solution from an acidic surfactant and finely divided polyolefin wax, and

(b) the dispersion is then neutralized by adding alkali metal hydroxides above the melting point of the wax. After it had been known to stabilize polyolefin wax dispersions through the use of surfactants and in particular neutralized alkyl phosphates, it was surprisingly found that particularly fine-particle dispersions of improved stability result if surfactants in acidic form, preferably acidic alkyl phosphates, and polyolefin waxes, if appropriate under pressure, are obtained subject to common neutralization.

Dispersant

In principle, anionic surfactants in their acidic, ie non-neutralized form are suitable as dispersants. Typical examples are alkylbenzenesulfonates, alkanesulfonates, olefin sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, o-methyl ester sulfonates, sulfofatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, hydroxy mixed ether sulfates, monoglyceride (ether) sulfates, monosulfate sulfates, fatty sulfates, fatty sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, sulfate, fatty sulfate Mono- and dialkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids, fatty acid isethionates, fatty acid sarcosinates, fatty acid retaurides, acyl lactylates, alkyl oligoglucoside sulfates and protein fatty acid condensates (especially herbal products based on soy). If the anionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably a narrow, homolog distribution. The dispersants are preferably alkyl or alkyl ether phosphates in the acidic form. Alkyl (ether.phosphates

Alkyl phosphates and alkyl ether phosphates are known anionic surfactants which are usually prepared by reacting optionally ethoxylated fatty alcohols with phosphorus pentoxide. Depending on the use ratio of the components, technical mixtures are obtained which predominantly contain mono- and dialkyl esters, in addition to triester, phosphoric acid and unreacted alcohol component. Overviews on this topic are, for example, by R.S.Cooper and G.Imokawa in J.Am.Oil.Chem.Soc. 4JL, 337 (1964) and 55, 839 (1978), H. Distler in Tenside Detergents 12, 263 (1975) and O'Lennick in Soap, Cosm., Chem. Spec. , 26 (1986).

Alkyl (ether) phosphates which are suitable for the purposes of the invention follow the formula (I),

OH

IR ¹ (OCH CH2) _n OP-OR ³ (I)

in which R * is a linear or branched alkyl radical having 6 to 22 carbon atoms, R ^ is hydrogen or a group R ¹ (OCH2CH2) _n ^{and n is} ° ° of the numbers from 1 to 10.

Typical examples are mono- and / or dialkyl esters based on adducts of 1 to 10, preferably 2 to 8, moles of ethylene oxide with capron alcohol, caprylic alcohol, 2-ethylhexyl alcohol, Caprinal alcohol, lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol, linolenyl alcohol, elaeostearyl alcohol, badenol alcohol, gadoleyl alcohol, arachyl alcohol, arachyl alcohol, arachyl alcohol, arachyl alcohol in the high-pressure hydrogenation of technical methyl esters based on fats and oils or aldehydes from Roelen's oxo-synthesis and as a monomer fraction in the dimerization of unsaturated fatty alcohols.

It is particularly preferred to use alkyl phosphates or alkyl ether phosphates with a degree of esterification in the range from 1 to 2.5 and preferably 1.3 to 2.1 based on 2-ethylhexanol or C12 / 14 or Ci2 / 18 ^{coconut oil} allo tallow - fatty alcohol and their adducts with 1 to 5 moles of ethylene oxide.

Polvolefin waxes

Polyolefin waxes are predominantly linear polyolefins with a wax-like character. Polypropylene and especially polyethylene waxes, which are products with relatively low molecular weights in the range from 500 to 20,000, are of technical importance. The polyolefin waxes are generally produced by direct high or low pressure polymerization of the monomers or by targeted depolymerization of products of relatively high molecular weights. Modified polyolefin waxes can be obtained by copolymerizing ethylene with suitable other monomers such as, for example, vinyl acetate. tat or acrylic acid can be produced. Finally, it is possible to improve the dispersibility of polyolefins by means of oxidative surface treatment. Overviews on this topic can be found, for example, in Ullmann's Encyclopedia of Industrial Chemistry (4th ed.), 2_, 36 and Enzcycl. Polym.Sci.Engng. 3/7, 792f.

For the purposes of the process according to the invention, the use of high-density polyethylene wax with an average molecular weight in the range from 500 to 10,000 and in particular 2,000 to 5,000 is preferred. The proportion of the acidic dispersant can be 1 to 40 and preferably 5 to 25% by weight, based on the polyolefin wax. The aqueous dispersions generally have a solids content of 1 to 40 and preferably 2 to 25% by weight.

Alkali hydroxides

The acidic dispersants are preferably neutralized with the addition of aqueous alkali metal hydroxide solutions. Typical examples are aqueous 5 to 25% by weight solutions of sodium and preferably potassium hydroxide.

Neutralization

The joint neutralization of acidic dispersant and polyolefin wax takes place above the melting point of the wax, preferably at temperatures in the range from 120 to 180 and in particular 150 to 160 ° C. The pressure can be 1 to 10 1

bar. The dispersion is preferably neutralized under an autogenous pressure of 2 to 6 bar. The dispersion is then cooled to room temperature.

Co-dispersants

In a preferred embodiment of the invention, the neutralization is carried out in the presence of a co-dispersant. Primarily nonionic surfactants of the formula (II) are suitable for this purpose,

in which R-- represents an alkyl and / or alkenyl radical having 6 to 22 carbon atoms or a nonylphenyl radical and m represents numbers from 1 to 20.

Typical examples are adducts of on average 1 to 20 and preferably 7 to 15 moles of ethylene oxide with fatty alcohols with 12 to 18 carbon atoms or nonylphenol such as, for example, C12 / 14-coconut fatty alcohol-9EO adduct, ^c 12 18 ~ ^Ko ^ ^os ^ ^etta ^ ^o ^ ^o l ~ 0- ^7E ^A ddukt, Ci5 / i3-tallow-14EO- adduct or nonyl phenol ioeo adduct.

Industrial applicability

The aqueous polyolefin wax dispersions obtainable by the process according to the invention are notable for a particularly fine distribution of the particles and an improved Θ

te storage stability and are suitable, for example, for coating solid surfaces and textile fabrics, such as fibers, yarns and textiles, and as defoamers.

The following examples are intended to explain the subject matter of the invention in more detail without restricting it.

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Examples

I. Substances used

AI) polyethylene wax, fixed point: 127 ° C average molecular weight: 5,000

Bl) stearyl phosphate, degree of esterification 1.5

B2) Stearyl phosphate sodium salt, degree of esterification 1.5

B3) Dodecylbenzenesulfonate potassium salt

^C1 ) Ci2 / 18 ^_ coconut ^fatty alcohol 9EO adduct F0RYL ( ^R ) 100, Henkel KGaA

II. Preparation of the dispersions

Example 1:

155 g of polyethylene wax Al were stirred into 500 ml of a 5% strength by weight solution of the acidic dispersant B1. The solids content of the resulting dispersion was approximately 27% by weight, the proportion of the dispersant - based on the wax - 16% by weight. The dispersion was neutralized with 25% by weight potassium hydroxide solution and then heated to 150 ° C. for 30 minutes. The mixture was then allowed to cool to room temperature. The dispersion was stored at 20 ° C. for 3 weeks and fine particle size or stability was assessed optically. Here mean: Fineness; +++ = almost clear dispersion

++ = slightly milky dispersion + = milky cloudy dispersion

Stability: +++ = no sediment ++ - very low sediment + - low sediment = significant sediment

The results are summarized in Table 1.

Example 2;

Example 1 was repeated, but the neutralization was carried out in an autoclave, an autogenous pressure of 6 bar being established at 150 ° C. The results are summarized in Table 1.

Example 3;

Example 1 was repeated, but the neutralization was carried out in the presence of 5% by weight, based on the dispersion, of the co-dispersant C1. The results are summarized in Table 1. Example 4;

Example 2 was repeated, but the neutralization was carried out in the presence of 5% by weight, based on the dispersion, of the co-dispersant C1. The results are summarized in Table 1.

Comparative Example VI:

Example 1 was repeated using the neutralized dispersant B2 and no subsequent neutralization was carried out. The results are summarized in Table 1.

Comparative example V2:

Example 1 was repeated using the neutralized dispersant B3 and no subsequent neutralization was carried out. The results are summarized in Table 1.

ΛZ.

Table 1 Results of the dispersion tests

Legend; D = dispersant

CD = Codispergator

Neutral. = Subsequent neutralization

Pressure = neutralization under pressure

Fine, = fine dispersion

Stable. = Stability of the dispersion

Claims

claims

1. A process for the preparation of stabilized aqueous polyolefin wax dispersions, characterized in that

(a) produces an aqueous solution from an acidic surfactant dispersant and finely divided polyolefin wax and

(b) the dispersion is then neutralized by adding alkali hydroxides above the melting point of the wax.

2. The method according to claim 1, characterized in that alkyl (ether) phosphates of the formula (I) are used as dispersants,

OH

IR ¹ (OCH2CH2) _n 0-P-0R ² (I)

in which R * is a linear or branched alkyl radical having 6 to 22 carbon atoms, R2 is hydrogen or a group R ¹ (OCH2CH2) _n ^{and n is} ° or numbers from 1 to 10. 1-f

3. Process according to claims 1 and 2, characterized gekenn¬ characterized in that the polyolefin wax high-density polyethylene wax used with an average molecular weight in the range of 500 to 10,000.

4. Process according to claims 1 to 3, characterized gekenn¬ characterized in that 1 to 40 wt .-% of the acidic dispersant - based on the polyolefin wax - ein¬.

5. Process according to claims 1 to 4, characterized gekenn¬ characterized in that aqueous dispersions with a solids content of 1 to 40 wt .-% is used.

6. The method according to claims 1 to 5, characterized gekenn¬ characterized in that one uses potassium hydroxide as the alkali hydroxide.

7. Procedure according to claims 1 to 6, characterized gekenn¬ characterized in that one carries out the neutralization at temperatures in the range of 120 to 180 ° C at pressures of 1 to 10 bar.

8. Process according to Claims 1 to 7, characterized in that the neutralization is carried out in the presence of nonionic surfactants of the formula (II),

R ³ 0 (CH ₂ CH2θ) _m H (II) in which R ^{3 represents} an alkyl and / or alkenyl radical having 6 to 22 carbon atoms or a nonylphenyl radical and m represents numbers from 1 to 20.