DE19934519A1 - Polyaddition reaction in mini-emulsion, for production of polyurethanes, polyureas and polyepoxides, comprises forming adduct of mini-emulsion in liquid medium and reacting - Google Patents

Abstract

Polyaddition reaction in mini-emulsion comprises forming an adduct of the mini-emulsion in a liquid medium and reacting.

Description

The invention relates to a method for carrying out poly addition reactions in mini emulsions.

Mini emulsion polymerization is a new method of hetero phase polymerization, which is the area of application of the classic Emul ion polymerisation expanded. Mini emulsions are dispersions from one aqueous phase, an oil phase and optionally one or more surface-active surfactants, in which unusually small droplets sizes can be realized. For polymerisation reactions in mini emulsions usually becomes a non-polar monomer or a mixture of mono mer and optionally a cosurfactant in water with the help of a Surfactants and using high shear fields to form droplets in the desired size dispersed by the added surfactant are colloidally stabilized (Sudol and El-Aasser, in: Emulsion Poly merization and emulsion polymers; Lovell, P.A .; El-Aasser, M. S., ed., Chichester (1997), 699). With such mini emulsions, the Droplet size continues to grow due to collisions and mergers.

The German patent application 198 52 784.5-43 describes the osmotic Stabilization of mini and micro emulsions using what serially insoluble compounds as emulsion stabilizing components. By adding the water-insoluble substance to the oil phase, the more common as the disperse phase of the emulsion is, an osmotic pressure built up by the surface tension of the emulsion droplets counteracts built-up capillary or Kelvin pressure. As a consequence, that Ostwald ripening of the emulsion droplets is delayed or avoided becomes.  

A production of polyaddition products by heterophase techniques has not been described yet. Are already on the market aqueous polyurethane or polyepoxide dispersions available. This are, however, in a procedurally complex manner as seconds därdispersionen manufactured, namely by condensation of the polyurethane or polyepoxides in an organic solvent, entry into water, then removing the organic solvent. Other watery Polyurethanes contain water-soluble amines and at least are partially water-soluble, so in the strict sense it does not constitute a dispersion represents.

Surprisingly, it was found that polyadditions in Miniemul sions are carried out while maintaining the particular character can. The starting materials used for polyaddition, for. B. Diamines and diepoxides for the production of polyepoxide dispersions or Diisocyanates and diamines and / or dialcohols for the production of poly urethane and / or polyurea dispersions in a suitable disperser yaw medium preferably with the aid of a surfactant and optionally one or more water-insoluble substances yaws and z. B. by adding a catalyst and / or by temperature increase brought to reaction. In this way, the ge is created directly wanted polymer dispersion. By varying the stoichiometry between Both reactants are also functional polymers, functional ones Particles, or functional by adding crosslinking agents Microgels accessible. Such dispersions are used in all areas possible, in which already aqueous polyepoxide or polyurethane disks persions are used, d. H. especially with adhesives, deckan paint and varnishes.  

The present invention relates to a method for Carrying out polyaddition reactions in mini emulsions, which is characterized in that one of the starting materials of the polyadditions miniemulsion containing reactions generated in a fluid medium and then reacting, whereby a dispersion of particles of Polyaddition product is obtained in the medium.

Polyadditions in the sense of the present invention are without elimination of by-products polycarbonate reactions in which by repeated addition of di- or polyfunctional starting materials in independent single reactions (step reactions) about the formation of reactive oligomers as discrete intermediates polyadducts being constructed. This includes both unipolyaddition reactions, at which are based on two types of monomers, as well as copolyadditions reactions involving more than two different types of monomers be used. Preferred examples of polyaddition reactions are Manufacture of polyurethanes from multifunctional hydroxy compounds and multifunctional isocyanates, the manufacture of polyureas multifunctional amines and multifunctional isocyanates and the Production of polyepoxides from multifunctional epoxides and multifunctional amines, thiols and / or hydroxy compounds.

The mini emulsion in which the polyaddition reaction is carried out can by using high shear fields, e.g. B. by an ultrasonic wand, a Jet disperser or a microfluidizer can be set. The emul Sion droplets are preferably on the order of 20 to 1000 nm, in particular from 30 nm to 600 nm, of average particles knife. Preferably, a miniemulsion of an oil phase in an in essential immiscible hydrophilic phase, e.g. B. a polar organic phase, but especially an aqueous phase.  

Surface stabilizers are preferably used to stabilize the emulsion Surfactants such as sodium dodecyl sulfate, cetyltrimethylammonium chloride or also polymeric surfactants, such as. B. block copolymers of styrene and Ethylene oxide added. The amount of surfactant is preferably in the range of 0.1 to 20% by weight, preferably 0.2 to 10% by weight and particularly preferably 0.5 to 5% by weight, based on the total weight of the emulsion.

In many cases this is sufficient for osmotic stabilization of the dispersion Presence of a hydrophobic addition component, i. H. one of the Educts. In the case of using polar, especially aqueous Dispersing media can, however, additionally be inert, i. H. not with the Polyaddition reaction involved, insoluble in the dispersing medium ultrahydrophobic compounds are added in general in an amount of 0.1 and 40% by weight, preferably 0.2 to 10% by weight and particularly preferably 0.5 to 5 wt .-% based on that Total weight of the emulsion.

Particularly suitable are ultrahydrophobic compounds which mix with the oil phase and have a solubility in the dispersing medium of preferably less than 5 × 10 ^-5 g / l, more preferably less than 5 × 10 ^-6 g / l and most preferably less than 5 × 10 ^{- 7} g / l, at room temperature. Examples include hydrocarbons, especially volatile and optionally halogenated hydrocarbons, silanes, organosilanes, siloxanes, long-chain esters, oils such as vegetable oils, e.g. B. olive oil, hydrophobic dye molecules, blocked isocyanates and oligomeric polymerization, polycondensation and polyaddition products.

The surfactants and ultrahydrophobic compounds are preferably so selected to be compatible with the resulting polyaddition product are. So substances can be used that have high volatility own or / and usefully if the polymeric dispersion are used, e.g. B. as a plasticizer, dye  etc. so that they can contribute positively to the target application. By Variation of the surfactants or / and the ultrahydrophobic compounds or their amounts in the reaction batch can be the particle size of the emulsion and the resulting polymer dispersion are set as desired become.

The polyaddition reaction in the miniemulsion can be carried out in a known manner are triggered, e.g. B. by adding a catalyst and / or by Temperature increase. It is preferable to start with a critical one stabilized and particularly preferably of a thermodynamically stable Emulsion. With such osmotically stabilized emulsions Dispersions of the polyaddition product are obtained, the Compared to the educt emulsion, particle size is not undesirable Way has changed. The particles of the polyaddition product have one average size of preferably 20 to 1000 nm and particularly preferred from 30 to 600 nm.

In addition, the inventive method is also suitable for the production of multi-phase nanohybrid particles, for. B. particles, the polyadducts and encapsulated therein inert solid particles, for. B. inorganic materials such as metal colloids, oxidic particles such as SiO ₂ , TiO ₂ , CaSO ₄ , CaCO ₃ , BaSO ₄ , zeolites, iron oxides, ZnO, CuO, CrO ₂ , ZrO ₂ , fluorine and hydroxyapatite and carbon black, or organic materials, such as containing colloidal dye aggregates. Solid particles are preferably encapsulated which have a hydrophobic or a hydrophobized surface. The surface can be made hydrophobic by adding substances which form a monolayer on the solid particles, for. B. long chain carboxylic acids. Furthermore, polyadducts or products (these then in small quantities as admixtures) can also be used for hydrophobizing the above-mentioned particles. The size of the solid particles is generally in the range from 0.5 to 400 nm, preferably in the range from 1 to 250 nm and particularly preferably in the range from 10 nm to 200 nm. The size of the emulsion droplets is adapted to the size of the solid particles to be encapsulated.

For polyadditions in mini emulsions, especially in osmotic stabilized emulsions, can be an efficient embedding of Solid particles can be achieved in the shell of polyaddition products. Preferably at least 60%, particularly preferably at least 80%, more preferably at least 90% and most preferred at least 95% of the solid particles are embedded. By polyaddition Dispersions obtained can be filmed homogeneously, the resulting films have high mechanical stability and acid resistance exhibit. Due to the homogeneous encapsulation, the resulting nanohybrid particles for example for colors or Coatings with a high coloristic efficiency can be used.

Evidence of the encapsulation of solid particles in the particles of the Polyaddition product can with the help of transmission Electron microscopy and / or ultracentrifugation.

Furthermore, the invention by the following figures and Examples are explained. It shows:

Fig. 1 is an electron micrograph of a latex made by polyaddition of Epikote E828 and 4,4'-diaminodi benzyl.

Examples example 1

6 g of a monomer mixture of Epikote E828 and Jeffamin D2000 (Structures see Table 1) in a molar ratio of 2: 1 became one Solution of 1 g of sodium dodecyl sulfate (surfactant) and 40 g of water and stirred for 1 h at the highest magnetic stirrer level. The mixture was for 2 min at 110 to 115 W with an ultrasonic wand (Branson Sonifier W450 digital, amplitude 90%) miniemulsified. By increasing the temperature the reaction was started at 60 ° C. The reaction time was 12 h. It became a stable dispersion of an amine-epoxy polyaddition product receive.

The particle size was measured using a Nicomp Particle Sizer (Model 370, PSS, Santa Barbara, USA) at a specified scattering angle of 90 °. The molecular weights of the polymers were determined by GPC analysis, which was carried out using a P1000 pump and a UV1000 detector (Thermo Separation Products) at a wavelength of 260 nm with 5 µm 8 × 300 mm SDV columns with 10 ⁶ , 10 ⁵ and 10 ³ angstroms (Polymer Standard Service) in THF with a flow rate of 1 ml / min at 30 ° C. The molecular weights were calculated using a calibration relative to the standards.

Electron micrographs were taken with a Zeiss / 912 Omega Electron microscope performed at 100 kV. The diluted Particle dispersions were coated on a 400 mesh carbon Copper grid applied and allowed to dry.

By varying the amount of surfactant (0.1 g, 0.5 g, 2.5 g and 4.0 g Sodium dodecyl sulfate) could result in the particle size Latex particles can be varied in the range from approximately 80 nm to 250 nm.  

The particle size could also be varied by varying the monomer (1,12-diaminododecane) and the surfactant (styrene / ethylene oxide block copolymer SE3030 (Sty) ₁₀ -b- (EO) ₂₃ ).

The results are summarized in Table 2.

Example 2

In accordance with the instructions given in Example 1, the surfactants used were cetyltrimethylammonium chloride (CTMA-Cl), Lutensol AT50 (C ₁₆ H ₃₃ ) (EO) ₅₀ and the styrene / ethylene oxide block copolymers PS / PEO1000 / 1050 (Sty) ₁₀ -b- (EO ) ₁₁₄ and SE1030 (Sty) ₃₀ -b- (EO) _{23 were used} instead of sodium dodecyl sulfate or SE3030. Particle sizes in the range between approximately 90 and 400 nm were obtained.

The results are shown in Table 3.

Example 3

Instead of a monomer mixture with the molar ratio of epoxy too Diamine of 2: 1, one component each was added in excess.

• a) Epoxy was in excess in a molar ratio to epoxy Amine from 2: 1 to 3.3: 1 added.
• b) The amine was epoxy in excess in a molar ratio added to amine from 1: 1.22 to 1: 1.5.

There were functional polyadducts with free primary Amine groups or epoxy groups obtained as starting materials for further reaction steps can be used.

The results of this experiment are shown in Table 4A.  

The particle size could be reduced by acidifying the latex. The results are shown in Table 4B.

Example 4

The experiment described in Example 1 was carried out using the amines 4,4'-diaminodibenzyl, 1,12-diaminododecane and 4,4'-diaminodicyclo hexylmethane (structures see Table 1) repeated. There were Polymer dispersions with particle sizes in the range of approx. 40 to 75 nm receive.

The results are shown in Table 5. Fig. 1 is an electron micrograph of the latex made using 4,4'-diaminodibenzyl.

Example 5

6 g of a monomer mixture of Epikote E828 and bisphenol A (structure see Table 1) were in a molar ratio of 1: 1 to a solution of 1 g of sodium dodecyl sulfate and 40 g of water and added for 1 h highest magnetic stirrer level stirred. According to that given in Example 1 A mini emulsion was prepared and allowed to react.

Analogously, but using 6 g of a monomer mixture of Epikote E828 and hexanedithiol (structure see Table 1) in Ratio 1: 1 a stable dispersion of a polysulfide was obtained.

The results are shown in Table 6.  

Example 6

6 g of a monomer mixture from the trifunctional epoxy Denacol Ex-314 (Structure see table 1) and Jeffamin D2000 in molar ratio of 1: 1.05 and 1: 1.1 were added to a solution of 1 g of sodium dodecyl sulfate and 40 g of water and for 1 h at the highest magnetic stirrer level touched. According to the procedure described in Example 1, a Mini emulsion made and reacted.

The experiment was carried out using the bifunctional epoxide Epikote E828, the tetrafunctional epoxy Ex-411 and with mixtures of one di- and a trifunctional epoxy or a di- and one tetrafunctional epoxy repeated.

The results are shown in Table 7.

Example 7

6 g of a monomer mixture of isophorone diisocyanate and 1.12- Diaminododecane or 4,4'-diaminodibenzyl each in a molar ratio 1: 1 became a solution of 1 g sodium dodecyl sulfate and 40 g water given and stirred for 1 h at the highest magnetic stirrer level. The mixture was 2 min (with diaminodibenzyl 12 min) with an amplitude of 90% (110 to 115 W) with the device already used in Example 1 miniemulsified. The reaction was caused by an increase in temperature 60 ° C started. The reaction time was 12 h.

The results of this experiment are shown in Table 8.  

Table 1

Overview of the monomer components used

Table 2

Table 3

Table 4A

Table 4B

Table 5

Table 6

Table 7

Table 8

Claims (12)

1. A process for carrying out polyaddition reactions in mini emulsions, characterized in that a miniemulsion containing the starting materials of the polyaddition reaction is generated in a fluid medium and then brought to reaction. 2. The method according to claim 1, characterized, that the polyaddition reaction is a manufacture of polyurethanes multifunctional hydroxy compounds and multifunctional Includes isocyanates. 3. The method according to claim 1, characterized, that the polyaddition reaction is a production of polyureas from multifunctional amino compounds and multifunctional Includes isocyanates. 4. The method according to claim 1, characterized, that the polyaddition reaction is a production of polyepoxide Compounds of multifunctional amino, hydroxy or / and Thiol compounds and multifunctional epoxides.   5. The method according to any one of the preceding claims, characterized, that a miniemulsion of a disperse oil phase in a continuous hydrophilic phase, especially an aqueous one Phase forms. 6. The method according to any one of the preceding claims, characterized, that you add a surfactant. 7. The method according to any one of the preceding claims, characterized, that in addition a hydrophobic inert substance in the system is introduced. 8. The method according to claim 7, characterized, that the hydrophobic substance in an amount of 0.1-40 wt .-% based on the total weight of the emulsion is used. 9. The method according to any one of the preceding claims, characterized, that the average particle size of the emulsion in the range of 30 to 600 nm. 10. The method according to any one of the preceding claims, characterized, that an emulsion is generated which stabilizes critically or thermodynamically stable against a change in particle size is.   11. The method according to any one of the preceding claims, characterized, that the emulsion further contains solid particles dispersed therein. 12. The method according to any one of the preceding claims, characterized, that the polyaddition reaction without significant change in Particle size is done.