EP1439905A1

EP1439905A1 - Method for producing (co)polymers of olefinically unsaturated monomers

Info

Publication number: EP1439905A1
Application number: EP02777321A
Authority: EP
Inventors: Hubert Baumgart; Werner-Alfons Jung; Heinz-Peter Rink; Edeltraud Hagemeister; Ulrike RÖCKRATH
Original assignee: BASF Coatings GmbH
Current assignee: BASF Coatings GmbH
Priority date: 2001-11-02
Filing date: 2002-10-21
Publication date: 2004-07-28
Also published as: WO2003037501A1; DE10154045A1

Abstract

The invention relates to a method for producing (co)polymers by (co)polymerization of olefinically unsaturated monomers in a reaction vessel. According to said method, (A) at least one fluid, which contains at least one olefinically unsaturated monomer and (B) at least one fluid, which contains at least one compound triggering the (co)polymerization, are mixed in a micromixer before the intake thereof into said reaction vessel. Said fluids (A) and (B) are dosed from an opposite direction into an integrated system, comprising microchannels, for the fluids (A) and (B), which are juxtaposed in a plane and engage with each other by periodic deformations of the walls thereof in the longitudinal direction. Said fluids flow through the microchannels in the opposite direction in a spatially separated manner and exit perpendicularly to the longitudinal direction of said microchannels, such that a current is produced above the outlet points, which comprises lamellae of the fluid (A) and (B), alternately juxtaposed and engaging with each other, and in which the fluids (A) and (B) mix by diffusion. Said invention also relates to the use of the so produced (co)polymers.

Description

Process for the preparation of (co) polymers of olefinically unsaturated monomers

The present invention relates to a new process for the preparation of (co) polymers of olefinically unsaturated monomers. In addition, the present invention relates to the use of the (co) polymers prepared by the new process as polymeric additives, coating materials, adhesives and sealants or for the production of coating materials, adhesives, sealants, films and moldings.

Processes for the preparation of (co) polymers of olefinically unsaturated monomers, in which a Taylor reactor is used as the reaction vessel, to which the olefinically unsaturated monomers and the compounds which trigger the (co) polymerization are fed via a mixing unit are described in German patent application DE 199 60 389 A 1 known. Conventional and known devices can be used as mixing units, the strong shear fields (see the German patent application, column 4, line 55, to column 5, line 13) or comparatively weak shear fields (see the German patent application, column 5, lines 14 to 21) generate. However, the (co) polymers of olefinically unsaturated monomers produced using the known method must be further improved with regard to their non-uniformity in the molecular weight.

From the international patent application WO 97/17133 a method for the continuous dispersion of at least one fluid A forming the disperse phase and at least one fluid B forming the continuous phase is known. In the process, the fluids are fed to a dispersing apparatus, where they meet in a dispersing room. For this purpose the fluid flows A and B in a microstructure disperser divided into a spatially separated, flowing fluid filament by a family of microchannels assigned to the fluids A and B, which flow into the dispersion chamber at the same flow rates for the respective fluid. At the outlet, a fluid jet of the disperse phase is immediately adjacent to a fluid jet of the continuous phase, so that a fluid jet of the disperse phase that disintegrates into particles is enveloped by the adjacent fluid jets of the continuous phase. The known micromixer is essentially limited to the production of dispersions. Whether - and if so, to what extent - it is also suitable as a mixing unit for the production of mixtures which consist of olefinically unsaturated monomers and the compounds which trigger (co) polymerization and which are to be subjected to (co) polymerization in bulk or in solution, is not known.

A process for continuous anionic (co) polymerization in solution is known from European patent application EP 0 749 987 A1. Stream A, which contains the olefinically unsaturated monomers, and stream B, which contains the initiators of the anionic polymerization, are each divided into two streams, after which the four streams are fed tangentially to a cyclone micromixer. The inlet openings alternate in the order A B / A / B. The process is tailored to anionic (co) polymerization. It is not known whether - and if so to what extent - the known process can be applied to cationic or radical (co) polymerization.

The object of the present invention is to find a new process for the preparation of (co) polymers of olefinically unsaturated monomers, in which (A) at least one fluid containing at least one olefinically unsaturated monomer, and

(B) at least one fluid which contains at least one compound which triggers the (co) polymerization,

mixed in a micromixer before entering the reaction vessel. The new process is said to be outstandingly suitable for cationic, anionic and free-radical (co) polymerization and also to deliver (co) polymers with a particularly narrow molecular weight distribution in free-radical (co) polymerization. The (co) polymers produced using the new process are said to be particularly suitable as polymeric additives, coating materials, adhesives and sealants and for the production of coating materials, adhesives, sealants, films and moldings. In particular, those produced with the aid of the process according to the invention by radical copolymerization

(Meth) acrylate copolymers are outstandingly suitable as high-solids coating materials, adhesives and sealants or for their manufacture.

Accordingly, the new process for the preparation of (co) polymers by the (co) polymerization of olefinically unsaturated monomers was found in a reaction vessel in which

(A) at least one fluid containing at least one olefinically unsaturated monomer, and

(B) at least one fluid which contains at least one compound which triggers the (co) polymerization, mixed in a micromixer before entering the reaction vessel, whereby the fluids (A) and (B) from the opposite direction are integrated into an integrated system of microchannels for the fluids which are interleaved in one plane and are interlocked by periodic deformation of their walls in the longitudinal direction (A) and (B) metered in that they flow spatially separated from one another in the opposite direction and leave perpendicular to the longitudinal direction of the microchannels, as a result of which a flow over the exit points results from alternately adjacent and interlocking lamellae of the fluids (A) and ( B) and in which the fluids (A) and (B) mix together by diffusion.

In the following, the new process for the preparation of (co) polymers by the (co) polymerization of olefinically unsaturated monomers in a reaction vessel is referred to for the sake of brevity as the “process according to the invention”.

In view of the prior art, it was surprising and unforeseeable for the person skilled in the art that the task, like the present one

Invention based, could be solved with the help of the inventive method. In particular, it was surprising that the process according to the invention was outstandingly suitable for cationic, anionic and free-radical (co) polymerization and also gave (co) polymers with a particularly narrow molecular weight distribution in free-radical (co) polymerization. The (co) polymers produced using the new process were particularly suitable as polymeric additives, coating materials, adhesives and

Sealants and for the production of coating materials, adhesives, sealants, films and molded parts. In particular The (meth) acrylate copolymers prepared with the aid of the process according to the invention by radical copolymerization were outstandingly suitable as high-solids coating materials, adhesives and sealing compounds or for their production.

In the process according to the invention, at least one, in particular one, fluid (A), which contains at least one olefinically unsaturated monomer, and at least one, in particular one, fluid (B), which contains at least one compound which triggers the (co) polymerization, is made from the opposite Directed metered in a micromixer. The metering can be carried out with the aid of customary and known devices, such as metering pumps. The flow can be monitored and regulated using conventional and known flow meters.

The fluids (A) and (B) are metered into an integrated system consisting of microchannels lying next to one another in one plane and interlocking in the longitudinal direction due to periodic deformations of their walls. The fluids (A) and (B) flow through the microchannels separately from one another in the opposite direction. They leave the microchannels perpendicular to their longitudinal direction. This creates a flow over the exit points, which consists of alternately lying and interlocking lamellae of the fluids (A) and (B). In this flow, the fluids (A) and (B) can mix very quickly by diffusion.

The residence time of the fluids (A) and (B) in the integrated system of microchannels is preferably from 0.01 to 10 ms. The duration of the mixing is preferably 5 to 100 ms, in particular 10 to 80 ms. The mixing can be carried out at 1 to 100, in particular 1 to 30, bar. The integrated system preferably contains 5 to 100, preferably 10 to 50 and in particular 10 to 20 microchannels for the fluids (A) and (B), the number of microchannels for the fluids (A) = the number of microchannels for the fluids (B).

When viewed in the longitudinal direction, the microchannels preferably have a slit-shaped profile consisting of two walls and a floor. When viewed in the longitudinal direction, the walls are preferably deformed in a wavy and / or zigzag shape. This results in microchannels that are essentially meandering.

The microchannels are preferably 750 μm to 3 mm, in particular 1 to 2 mm, long. Their width is preferably 10 to 100, in particular 20 to 50 μm. The wall thickness of the microchannels can vary, the wall thickness preferably corresponds approximately to the width of the microchannels.

The microchannels are arranged on a flat substrate and firmly connected to it. The microchannels and the flat substrate can consist of different materials; they are preferably made of the same material. They preferably consist of glass, ceramic or metal, preferably of metal. The metal is particularly preferably selected from the group consisting of stainless steel, nickel, copper and silver.

In addition to the integrated system described above, the micromixer to be used according to the invention contains customary and known supply lines and inlet devices for the fluids (A) and (B). It also includes an outlet with a suitable connection to the reaction vessel. The integrated system is stored in the micromixer so that it cannot be mechanically deformed. The wall thickness of the micromixer, the seals and the connectors are designed pressure-tight. In addition, the micromixer may include devices for heating and / or cooling the fluids and conventional and known mechanical, hydraulic, optical and electronic devices for measuring and regulating the pressure, temperature, viscosity, flow rates, etc.

The micromixers to be used according to the invention are devices known per se and are sold, for example, by the company IMM under the name LIGA Micromixing System (Micromixer). Their structure and mode of operation are described, for example, in “Operating Manual LIGA Micromixing System (Micromixer)”, August 1998.

In the process of the invention, the (co) polymerization can be carried out continuously or batchwise. The olefinically unsaturated monomers can be (co) polymerized cationically, ionically or radically, in particular radically. The (co) polymerization is preferably carried out in bulk or in solution.

The process according to the invention is preferably used for the copolymerization. According to the invention, the copolymerization comprises the random and alternating copolymerization and the block mixed polymerization and graft mixed polymerization. It is a particular advantage of the process according to the invention that the block mixed polymerization and graft mixed polymerization can be carried out in a particularly targeted and very reproducible manner

The pressure used in (co) polymerization and the applied

Temperatures can vary widely and depend essentially on the vapor pressure and the reactivity of the olefinically unsaturated Monomers, the vapor pressure of any solvents used, the decomposition temperatures of monomers and solvents and the depolymerization temperatures of the resulting (co) polymers. A pressure of 1 to 100 bar and a temperature of -20 to 250 ° C. are preferably used.

The olefinically unsaturated monomers which are contained in the fluid (A) or of which the fluid (A) consists can come from a wide variety of monomer classes. Examples of suitable monomers are described in detail in German patent application DE 199 30 067 A1, page 4, line 28, to page 6, line 27, or in German patent application DE 199 60 389 A1, column 12, line 18, to column 13, line 9. At least one of the olefinically unsaturated monomers is preferably a (meth) acrylate. The profile of properties of the (co) polymers, in particular of the copolymers, is preferably determined primarily by the monomers from the (meth) acrylate class. The particularly preferred (co) polymers, in particular copolymers, are therefore (meth) acrylate (co) polymers, in particular

(Meth) acrylate copolymers.

(Meth) acrylate copolymers are used in the German

Patent applications DE 199 30 067 A1, DE 199 60 389 A1, DE 198 39 453 A1, page 4, line 50, to page 5, line 54, DE 42 04 518 A1, page 3, line 65, to page 4, line 43, DE 43 10 414 A 1, page 2, line 50, to page 4, line 41, DE 199 24 171 A 1, page 5, line 54, to page 7, line 37, or in DE 198 50 243 A 1 described in detail.

The fluid (B) contains at least one that triggers the (co) polymerization

Connection. The selection of this compound depends on the reaction mechanism by which the (co) polymerization, in particular Copolymerization, should take place. Accordingly, the compound is an initiator for cationic polymerization, an initiator for anionic polymerization, an initiator for radical polymerization, a photoinitiator which can initiate the cationic, anionic or radical, in particular radical, polymerization , or a thermally activatable olefinically unsaturated monomer.

Examples of initiators of cationic polymerization are protonic acids, such as sulfonic acids; Lewis acids or Friedel-Crafts catalysts, such as boron trifluoride, aluminum trichloride, titanium tetrachloride, tin tetrachloride, antimony pentachloride and their mixtures and adducts with Lewis bases, such as ether; and carbonium ion salts such as triphenylcarbonium hexachloroantimonate, hexafluoroantimonate and hexafluorophosphate.

Examples of initiators of anionic polymerization are potassium amide, butyllithium and Grignard reagents. Further examples of suitable initiators of anionic polymerization are known from European patent application EP 0 749 987 A1, page 4, line 9, to page 5, line 39.

Examples of initiators of radical polymerization are known from German patent applications DE 199 30 067 A1, page 6, lines 27 to 35, and DE 199 60 389 A1, column 13, lines 10 to 25.

Examples of suitable photoinitiators are described in Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998, pages 444 to 446. An example of a thermally activatable olefinically unsaturated monomer is styrene.

In addition, the fluids (A) and (B) can also contain organic solvents and additives, as are usually added to reaction mixtures in (co) polymerisation. Examples of suitable additives are wetting agents, defoamers, dispersants or molecular weight regulators.

The reaction vessel downstream of the mixer to be used according to the invention, in which the (co) polymerization, in particular the copolymerization, takes place, is preferably a stirred tank, an autoclave, a stirred tank cascade, an extruder, a loop reactor, a tubular reactor or a Taylor reactor. Examples of suitable reaction vessels are found in patent applications DE 197 09 465 A1, DE 197 09 476 A1, DE 28 48 906 A1, DE 195 24 182 A1, DE 198 28 742 A1, DE 199 60 389 A1, DE 196 28 143 A1, DE 196 28 142 A1, EP 0 554 783 A1, WO 95/27742, WO 82/02387 or WO 98/02466.

At the product outlet of the reaction vessel, a pressure-maintaining valve can be arranged, which builds up and regulates the pressure in the reaction vessel and through which the (co) polymers, in particular the copolymers, can be discharged continuously or discontinuously. However, the pressure can also be built up by injecting inert gas or by the gas phase of an organic solvent.

The pressure-maintaining valve or the product outlet can be followed by collecting and storage containers, mixing devices, such as devices for melt emulsification, cooling belts for producing granules, or other reactors. The reaction vessels can be equipped with a heating or cooling jacket, so that they can be heated or cooled in cocurrent or in countercurrent. Furthermore, they can contain customary and known mechanical, hydraulic, optical and electronic measuring and control devices, such as temperature sensors, pressure meters, flow meters, optical or electronic sensors and devices for measuring substance concentrations, viscosities and other physico-chemical variables that match their measured values to a Forward data processing system that controls the entire sequence of the method according to the invention.

The reaction vessels are preferably designed to be pressure-tight, so that the reaction medium can preferably be under a pressure of 1 to 100 bar. They can consist of a wide variety of materials, as long as they are not attacked by the starting materials and the reaction products and can withstand higher pressures. Metals, preferably steel, in particular stainless steel, are preferably used.

The process according to the invention is outstandingly suitable for cationic, anionic and free-radical (co) polymerization and also delivers (free) (co) polymers with a particularly narrow molecular weight distribution in free-radical (co) polymerization. In addition, gel particle-free copolymers are obtained even when using higher amounts of hydroxyl-containing olefinically unsaturated monomers.

The (co) polymers produced using the new process are particularly suitable as polymeric additives, such as rheology aids or thickeners, coating materials, adhesives and sealants, and for the production of coating materials, adhesives, sealants, films and molded parts. The (meth) acrylate copolymers prepared by means of the free-radical copolymerization using the process according to the invention are particularly suitable as high-solids coating materials, adhesives and sealants or for their production.

The particular advantages of the process according to the invention and of the (meth) acrylate copolymers prepared therewith become particularly apparent with the aid of the coating materials which contain the (meth) acrylate copolymers in question as binders. Depending on their composition, these coating materials are physically drying or are cured thermally, with actinic radiation, in particular UV radiation, or by electron radiation, or thermally and with actinic radiation.

They are available as powder coatings, powder slurry coatings, coatings dissolved in organic media, aqueous coatings or as essentially or completely solvent and water-free, liquid coatings (100% systems). You can use one-component systems or two- or

Be multi-component systems. In addition, they can contain coloring and / or effect pigments and other customary and known paint-typical additives. They are used as architectural paints for indoor and outdoor use, as paints for furniture, doors, windows, hollow glass bodies, coils, containers, white goods and other industrial applications, as automotive paints for original equipment (OEM) or as car refinish paints. When used in the automotive sector, they can be used as electrocoating paints, fillers, solid-color topcoats, basecoats and clearcoats, which can be used to advantage for the production of color and / or effect multi-layer coatings by the customary and known wet-on-wet processes , Examples and comparative tests

Example 1 and comparative experiment V1

The preparation of a methacrylate copolymer by the process according to the invention (example 1) and by a known process (comparative test V 1)

A suitable stainless steel reactor equipped with a stirrer, reflux condenser, an inlet vessel for the monomers and an inlet vessel for the initiator solution was used in each case for example 1 and comparative experiment V1. In Example 1, a micromixer LIGA Micromixing System (Micromixer) from IMM was connected between the feed vessels and the reaction vessel.

30.4 parts by weight of Solventnaphta ® were weighed into each of the reaction vessels and heated to 143.degree.

The initiator feed, each consisting of 6.1 parts by weight of tertiary-butylperoxyethylhexanoate and 2.5 parts by weight of Solventnaphta®, was metered in uniformly within 4 hours and 45 minutes.

The monomer feed was started 15 minutes after the start of the initiator feed. The monomer feed consisted of 8.54 parts by weight of styrene, 18.3 parts by weight of ethylhexyl methacrylate, 7.32 parts by weight of n-butyl methacrylate, 7.32 parts by weight

Hydroxyethyl methacrylate, 18.3 parts by weight of butanediol-1, 4-monoacrylate and 1.22 parts by weight of acrylic acid and was metered in uniformly over four hours. During the feeds, the reaction temperatures were kept at 143 ° C. After the feeds had ended, the polymerization was continued for two hours.

The methacrylate copolymer of Example 1 produced in the procedure according to the invention had a solids content of 65.1% by weight (one hour / 130 ° C.), an acid number of 17.5 mg KOH / g and a viscosity (δO percent in Solventnaphta®) of 2, 5 dPas on. The number average molecular weight measured with the aid of gel permeation chromatography with polystyrene as the internal standard was 2,317 daltons, the mass average molecular weight was 5,130 daltons, corresponding to a non-uniformity in the molecular weight of 2.21.

The methacrylate copolymer of comparative test V 1 produced in a procedure not according to the invention had a solids content of 60.7% by weight (one hour / 130 ° C.), an acid number of 16 mg KOH / g and a viscosity (60 percent in Solventnaphta®) of 11 dPas on. The number average molecular weight measured using gel permeation chromatography with polystyrene as the internal standard was 2,994 daltons, the mass average molecular weight was 8,698 daltons, corresponding to a non-uniformity in the molecular weight of 2.9.

Thus, the methacrylate copolymer of Example 1 produced in the procedure according to the invention had a narrower molecular weight distribution and a lower viscosity than the methacrylate copolymer of Comparative Experiment V 1 and was therefore much better than this as a binder for coating materials with a high solids content.

Example 2 and comparative experiment V2 The preparation of a methacrylate copolymer by the process according to the invention (example 2) and by a known process (comparative test V 2)

A suitable stainless steel reactor, equipped with a stirrer, reflux condenser, an inlet vessel for the monomers and an inlet vessel for the initiator solution, was used in each case for example 2 and the comparative experiment V2. In Example 2, a micromixer LIGA Micromixing System (Micromixer) from IMM was connected between the feed vessels and the reaction vessel.

In each case 31.1 parts by weight of Solventnaphta® were introduced and heated to 150 ° C. under a pressure of 4 bar.

The initiator feed, each consisting of 2.85 parts by weight of ditertiarbutyl peroxide and 2.6 parts by weight of Solventnaphta®, was metered in uniformly within four hours and 45 minutes.

The monomer feed was started 15 minutes after the start of the initiator feed. The monomer feed consisted of 8.86 parts by weight of styrene, 19.04 parts by weight of ethylhexyl methacrylate, 7.63 parts by weight of n-butyl methacrylate, 7.63 parts by weight

Hydroxyethyl methacrylate, 19.04 parts by weight of butanediol-1,4-monoacrylate and 1.27 parts by weight of acrylic acid and was metered in uniformly over four hours.

During the feeds, the reaction temperatures were kept at 150 ° C. After the feeds had ended, the polymerization was continued for two hours. The methacrylate copolymer of Example 2 produced in the procedure according to the invention had a solids content of 63.4% by weight (one hour / 130 ° C.), an acid number of 15.4 mg KOH / g and a viscosity (original) of 7.6 dPas , The number average molecular weight measured using gel permeation chromatography with polystyrene as the internal standard was 2,473 daltons, the mass average molecular weight was 6,385 daltons, corresponding to a non-uniformity in the molecular weight of 2.58.

The methacrylate copolymer of comparative test V 2 produced in a procedure not according to the invention had a solids content of 68.5% by weight (one hour / 130 ° C.), an acid number of 15.1 mg KOH / g and a viscosity (original) of 67.2 dPas on. The number average molecular weight measured using gel permeation chromatography with polystyrene as the internal standard was 3,281 daltons, the mass average molecular weight was 13,897 daltons, corresponding to a non-uniformity in the molecular weight of 4.2.

Thus, the methacrylate copolymer of Example 2 produced in the procedure according to the invention had a narrower molecular weight distribution and a lower viscosity than the methacrylate copolymer of Comparative Experiment V 2 and was therefore much better than this as a binder for coating materials with a high solids content.

Claims

1. Process for the preparation of (co) polymers by the (co) polymerization of olefinically unsaturated monomers in a reaction vessel in which

mixed with one another in a micromixer before entering the reaction vessel, characterized in that the fluids (A) and (B) from the opposite direction into an integrated system of microchannels which are adjacent to one another in a plane and are interdigitated by periodic deformations of their walls in the longitudinal direction the fluids (A) and (B) are metered in, flowing through them spatially separated from one another in the opposite direction and leaving perpendicular to the longitudinal direction of the microchannels, which results in a flow over the outlet points, which consists of alternately lying and interlocking lamellae of the

There are fluids (A) and (B) and in which the fluids (A) and (B) mix with one another by diffusion.

2. The method according to claim 1, characterized in that the integrated system each 5 to 100 microchannels for the fluids (A) and (B), with the proviso that the number of microchannels for the fluids (A) = the number of microchannels for the fluids (B).

3. The method according to claim 1 or 2, characterized in that the integrated system contains 10 to 50 microchannels for the fluids (A) and (B).

4. The method according to any one of claims 1 to 3, characterized in that the microchannels, seen in the longitudinal direction, have a slit-shaped profile made of two walls and a floor.

5. The method according to claim 4, characterized in that the walls, seen in the longitudinal direction, are wavy and / or zigzag-shaped.

6. The method according to claim 5, characterized in that the walls are deformed in a wave shape.

7. The method according to any one of claims 1 to 6, characterized in that the microchannels are 750 microns to 3 mm long.

8. The method according to any one of claims 1 to 7, characterized in that the microchannels are 10 to 100 microns wide.

9. The method according to claim 8, characterized in that the microchannels are 20 to 50 microns wide.

10. The method according to any one of claims 1 to 9, characterized in that the integrated system consists of glass, ceramic or metal.

11. The method according to claim 10, characterized in that the metal is selected from the group consisting of stainless steel, nickel, copper and silver.

12. The method according to any one of claims 1 to 11, characterized in that the (co) polymerization is carried out continuously or batchwise.

13. The method according to any one of claims 1 to 12, characterized in that the olefinically unsaturated monomers are cationically, anionically or radically (co) polymerized.

14. The method according to claim 13, characterized in that the (co) polymerization is carried out in bulk or in solution.

15. The method according to any one of claims 1 to 14, characterized in that at least one of the olefinically unsaturated monomers is a (meth) acrylate.

16. The method according to claim 15, characterized in that the (co) polymers (meth) acrylate (co) polymers.

17. The method according to any one of claims 1 to 16, characterized in that the (co) polymerization triggering compound is an initiator for cationic polymerization

An initiator for anionic polymerization, an initiator for radical polymerization, a photoinitiator or a thermally activatable olefinically unsaturated monomer.

18. The method according to any one of claims 1 to 17, characterized in that the reaction vessel is a stirred tank, an autoclave, a stirred tank cascade, an extruder, a tubular reactor, a loop reactor or a Taylor reactor.

19. Use of the (co) polymers prepared according to one of claims 1 to 18 as polymeric additives, coating materials, adhesives and sealing compounds and for the production of coating materials, adhesives,

Sealants, molded parts and foils.