WO2015117857A1

WO2015117857A1 - Polymerisation in n-formylmorpholine

Info

Publication number: WO2015117857A1
Application number: PCT/EP2015/051537
Authority: WO
Inventors: Ulrich Karl; Michael Dornbusch
Original assignee: Basf Se
Priority date: 2014-02-06
Filing date: 2015-01-27
Publication date: 2015-08-13

Abstract

The invention relates to a method for the production of polymers by the radical polymerisation of monomers in a solvent, said method being characterised in that a maximum 10 wt. % of the monomers are monoethylenically unsaturated dicarboxylic acids or derivatives thereof and that the solvent contains N-formylmorpholine (NFM), N-acetylmorpholine (NAM) or mixtures thereof.

Description

Polymerization in N-formylmorpholine

The invention relates to a process for the preparation of polymers by radical polymerization of monomers in a solvent, which is characterized in that a maximum of 10 wt.% Of the monomers are monoethylenically unsaturated dicarboxylic acids or derivatives thereof and

- The solvent N-formylmorpholine (short NFM), N-acetylmorpholine (short NAM) or mixtures thereof.

There are several methods for the radical polymerization of monomers. Frequently, solvents are used in processes of free-radical polymerization, may be mentioned z. As ketones such as acetone, butane-2-οη, esters such as ethyl acetate or aromatic solvents such as toluene or benzene.

In principle, there is a need for alternative solvents suitable for carrying out the free-radical polymerization.

No. 3,463,764 describes the free-radical polymerization of monomer mixtures in a polar solvent. The polymer mixtures necessarily have a content of ethylenically unsaturated dicarboxylic acids. The content of the ethylenically unsaturated dicarboxylic acids in the resulting polymer is generally about 20% in the examples of US Pat. No. 3,463,764. Ethylenically unsaturated dicarboxylic acids copolymerize strictly alternating with the concomitant use of other monomers. No. 3,463,764 also mentions N-formylmorpholine as a possible solvent among many other solvents.

From US 3897404 solutions of poly (alkyl acrylates) in polar solvents are known. The poly (alkyl acrylates) are reacted with amines in these solvents. As a solvent, among others, N-formylmorpholine is mentioned.

N-formylmorpholine is also mentioned in EP-A 2128207 as a possible co-solvent in printing inks and in US 5476743 as a possible additive to developers for copiers.

The desired alternative solvents should be inexpensive and be well suited for carrying out the radical polymerization. In particular, they should allow the production of polymers with sufficiently high molecular weight. The resulting polymers or the solutions or dispersions of the polymers should show no or at most only slight discoloration. Alternative solvents should also allow the highest possible solids contents of the resulting solutions or dispersions. Also of great value are favorable toxicological properties - in particular, the solvents should have no carcinogenic, mutagenic or reprotoxic properties - and the highest possible flash point. Accordingly, the method defined above was found.

To the monomers In the process, polymerizable, ethylenically unsaturated compounds (in short monomers) are radically polymerized. The monomers contain at least one polymerizable, ethylenically unsaturated group. It may be z. B. be a vinyl, allyl or acrylic group. The monomers preferably contain one to three ethylenically unsaturated groups, in particular one or two ethylenically unsaturated groups.

In a particularly preferred embodiment, the monomers are predominantly those with only one polymerizable ethylenically unsaturated group; the proportion of monomers having a polymerizable ethylenically unsaturated group is therefore in particular at least 90% by weight, more preferably at least 95% by weight or at least 98% by weight, based on the total weight of all monomers. In a very particularly preferred embodiment, the monomers are exclusively those having only one polymerizable, ethylenically unsaturated group.

The proportion of monoethylenically unsaturated dicarboxylic acids or their derivatives, such as maleic acid, fumaric acid, their anhydrides, diesters, monoesters or amides, is at most 10% by weight, preferably at most 5% by weight, in particular at most 2% by weight, based on the Total weight of all monomers. In a particular embodiment, monoethylenically unsaturated dicarboxylic acids or their derivatives are not used. Monoethylenically unsaturated dicarboxylic acids or derivatives thereof, in contrast to other monomers, polymerize in a strictly alternating manner. Copolymers of monoethylenically unsaturated dicarboxylic acids or their derivatives with other monomers therefore differ fundamentally from copolymers which are prepared without the concomitant use of monoethylenically unsaturated dicarboxylic acids or derivatives thereof.

In a preferred embodiment, at least 5% by weight of the monomers are hydrophilic monomers which are selected from those having an acid group, which may optionally also be in the form of a salt, having a hydroxyl group, a nitrile group, an amino group, which may be present may also be present as a salt, an amide group, with a lactam group or an epoxy group.

Monomers having an acid group are e.g. For example, those having a carboxylic acid, sulfonic acid or phosphonic acid group, wherein the above acid groups may also be present as a salt. Suitable examples include salts with an inorganic cation such as alkali cations or an ammonium cation or organic cations, eg. As substituted by organic groups ammonium cations. In particular, mention may be made of acrylic acid, methacrylic acid [in brief, (meth) acrylic acid], vinylsulfonic acid, vinylphosphonic acid or salts thereof.

Monomers having a hydroxyl group are e.g. Hydroxy-alkyl (meth) acrylates, in particular hydroxy-C 2 -C 8 -alkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate or hydroxy-2-ethylhexyl (meth) acrylate.

Monomers having a nitrile group are e.g. Acrylonitrile or methacrylonitrile. Monomers having an amino group are z. For example, by an amino group substituted alkyl (meth) acrylates.

Monomers having an amide group are e.g. As acrylamide or methacrylamide. Monomers having a lactam group are e.g. N-vinylpyrrolidone, N-vinylimidazole or N-vinylcaprolactam.

Monomers having an epoxy group are e.g. B. (meth) glycidyl acrylate. In a preferred embodiment, the proportion of monomers having a nitrile group, an amino group or an amide group is not more than 10% by weight, in particular not more than 5% by weight, particularly preferably not more than 2% by weight, based on the total weight of all monomers. In a particular embodiment, monomers having a nitrile group, an amino group and an amide group are not used.

Preferred hydrophilic monomers are therefore selected from those having an acid group, which may optionally also be in the form of a salt, having a hydroxyl group or a lactam group. Particularly preferred hydrophilic monomers are those having an acid group, which may optionally also be in the form of a salt, or a hydroxyl group.

At least 20% by weight of the monomers are particularly preferably hydrophilic monomers, in particular at least 20% by weight of the monomers are hydrophilic monomers with an acid group, which may optionally also be in the form of a salt, or with a hydroxyl group ,

Preferred hydrophilic monomers include its C 1 - to C 10 -hydroxyalkyl (meth) acrylates, (meth) acrylic acid or mixtures thereof.

In addition to the monomers listed above are suitable as further, free-radically polymerizable monomers (hereinafter referred to as "other monomers"). These are in particular monomers with an acrylic or methacrylic group, eg. B. C1 to C8 alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, vinylaromatic monomers such as styrene, vinyl esters such as vinyl acetate, Vinyl ethers such as ethyl vinyl ether or butyl vinyl ether or olefins such as ethene or propene.

In a particular embodiment, at least 60% by weight, particularly preferably at least 80% by weight, of all monomers of the monomer mixture are monomers having a (meth) acrylic group, regardless of whether they are hydrophilic monomers with a

(Meth) acrylic group (see above) or other monomers having a (meth) acrylic group (see above) or mixtures thereof.

The monomer mixture polymerized in the process is preferably composed of a) 0 to 10% by weight of dicarboxylic acids or derivatives thereof

b) 20 to 100% by weight of the above hydrophilic monomers

c) 0 to 80% by weight of a) and b) various other monomers The monomer mixture polymerized in the process is particularly preferably composed of a) from 0 to 2% by weight of dicarboxylic acids or derivatives thereof

b) 20 to 100% by weight of the above hydrophilic monomers

c) 0 to 80% by weight of a) and b) various other monomers

The monomer mixture polymerized in the process is very particularly preferably composed of a) from 0 to 2% by weight of dicarboxylic acids or derivatives thereof

b) 60 to 100% by weight of the above hydrophilic monomers

c) 0 to 40% by weight of a) and b) various other monomers

Curing by cross-linking

By choosing suitable hydrophilic monomers whose functional groups can react with one another, it is possible to prepare self-crosslinking polymers which have particularly high mechanical and chemical resistance after thermal curing has taken place. Frequently hardeners are added to the polymer which can react with the functional groups of the hydrophilic monomers. The hardeners include, for example, melamine resins, isocyanates, oligoamines, polyesters with free acid groups and others. To the solvent

The solvent used in the radical polymerization contains N-formylmorpholine (short NFM), N-acetylmorpholine (short NAM) or mixtures thereof.

The solvent is preferably at least 30% by weight, more preferably at least 50% by weight, most preferably at least 70% by weight, of NFM, NAM or mixtures thereof. The solvent is particularly preferably at least 30% by weight, more preferably at least 50% by weight, most preferably at least 70% by weight, of NFM.

In a particular embodiment, only NFM, NAM or mixtures thereof are used as solvents. In a very particular embodiment, only NFM is used as the solvent.

In addition to NFM, NAM or mixtures thereof, the solvent used may contain other compounds which are suitable as solvents. Called its hydrophobic solvent such. As toluene, o-xylene, p-xylene, cumene, chlorobenzene, ethylbenzene or technical mixtures of alkylaromatics.

Preferably, the other compounds used as solvents are hydrophilic compounds. Mention may be made of water, monoalcohols such as methanol, ethanol, isopropanol, n-butanol, ketones such as acetone, cyclohexanone, butan-2-one, (methyl ethyl ketone, MEK), methyl isobutyl ketone (MIBK) or isophorone, ethers such as tetrahydro -furan, dioxane, diethyl ether, tert-butyl methyl ether, esters such as the methyl, ethyl or butyl ester of acetic acid, or glycols or polyether glycols having terminal hydroxyl groups or terminal ether groups such as ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, their monomethyl or dimethyl ethers or carbonates such as 1, 2-propylene carbonate, ethylene carbonate or a mixture thereof.

In a particular embodiment of the process, the solvent used is a solvent mixture which, in addition to NFM or NAM, also contains 1, 2-propylene carbonate. Preferably, the solvent mixture contains at least 5 wt.% 1, 2-propylene carbonate, in addition to the above amounts or preferred amounts of NFM or NAM.

In particular, the solvent mixture contains not more than 20% by weight, in particular not more than 10% by weight, more preferably not more than 5% by weight, of other solvents than NFM, NAM and 1,2-propylene carbonate.

In particular, for example, solvent mixtures are suitable which from 5 to 95 wt.% NFM, NAM or mixtures thereof, in particular NFM, and

5 to 95 wt.% 1, 2-propylene carbonate and

0 to 10 wt.% More solvents are particularly suitable. Solvent mixtures are suitable, which from

20 to 80 wt.% NFM, NAM or mixtures thereof, in particular NFM, and

20 to 80 wt.% 1, 2-propylene carbonate and

0 to 5 wt.% More solvents exist

For polymerization

The polymers can be prepared by conventional polymerization techniques, e.g. by emulsion, suspension and solution polymerization.

The emulsion polymerization is carried out in the presence of emulsifiers. The emulsifiers produce monomer droplets (micelles) which are emulsified in the solvent. The polymerization takes place in the micelles. In the suspension polymerization, the polymerization takes place in the solution, but the polymer obtained is insoluble in the solvent and accumulates in the form of dispersed particles (bead polymerization) or precipitates completely from the solution (precipitation polymerization). In suspension polymerization, protective colloids may be included to prevent clumping of the polymers.

In the solution polymerization, the polymerization takes place in the solution, but the resulting polymer is soluble or colloidally dispersible in the solvent. A polymer solution is obtained which is used directly for many applications, in particular for coating agents, such as paints, adhesives or others. The solvent must therefore also be suitable for these applications.

Preference is given to solution and suspension polymerization, very particular preference being given to solution polymerization. By polymerization in solution lower molecular weights can be achieved than in the emulsion and suspension polymerization, whereby the viscosity of the polymer solutions remains lower and the flow properties are improved.

In the polymerization processes mentioned, preference is given to operating under exclusion of oxygen, preferably under nitrogen. The polymerization can be carried out batchwise, semicontinuously or continuously. In the batch-wise implementation of the solvent, the monomers and required auxiliaries are presented and then carried out the polymerization. In semi-continuous At least one starting material, generally the monomers, is fed continuously during the polymerization. In the continuous mode of operation, all starting materials and end products are continuously supplied or removed. The polymerization may, for. B. at temperatures from 20 to 300, preferably from 60 to 200 ° C are performed. Depending on the choice of the polymerization conditions, it is possible to set weight-average molecular weights Mw of from 800 to 5,000,000, in particular from 1,000 to 1,000,000. The weight-average molecular weights Mw are preferably greater than 5,000. Particular preference is given to weight-average molecular weights of 5,000 to 500,000. Mw is determined by gel permeation chromatography using PMMA as standard.

In the polymerization, auxiliaries can be used. Such auxiliaries are, in particular, free-radical-forming compounds (initiators), emulsifiers or protective colloids. The polymerization is preferably carried out in the presence of initiators. The amount of initiators is preferably 0.05 to 15, particularly preferably 0.2 to

8 parts by weight, based on 100 parts by weight of the monomers used in the polymerization. For multicomponent initiator systems (e.g., redox initiator systems), the foregoing weights refer to the sum of the components.

Suitable polymerization initiators are, for example, peroxides, hydroperoxides, Peroxidisul- fate, percarbonates, peroxyesters, hydrogen peroxide and azo compounds. Examples are hydrogen peroxide, dibenzoyl peroxide, dicyclohexyl peroxydicarbonate, dilauroyl peroxide, methyl ethyl ketone peroxide, di-tert-butyl peroxide, acetylacetone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butyl perneodecanoate, tert-amyl perpivalate, tert-butyl perpivalate, tert-butyl. Butylperneohexanoate, tert-butyl per-2-ethylhexanoate, tert-butyl perbenzoate, lithium, sodium, potassium and ammonium peroxydisulfate, azodiisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2- (carbamoylazo ) isobutyronitrile and 4,4-azobis (4-cyanovaleric acid). The initiators can be used alone or mixed with each other.

Redox initiator systems can also be used as initiators. Such redox initiator systems contain at least one peroxide-containing compound in combination with a redox coinitiator, e.g. reducing sulfur compounds, for example, bisulfites, sulfites, thiosulfates, dithionites and tetrathionates of alkali metals and ammonium compounds. Thus, combinations of peroxodisulfates with alkali metal or ammonium hydrogen sulfites, e.g. Ammonium peroxydisulfate and ammonium bisulfite.

In the emulsion polymerization, anionic, nonionic, cationic or amphoteric emulsifiers can be used. Anionic emulsifiers are, for example, alkylbenzenesulfonic acids, sulfonated fatty acids, sulfosuccinates, fatty alcohol sulfates, alkylphenol sulfates and fatty alcohol ether sulfates. Examples of nonionic emulsifiers which can be used are alkylphenol ethoxylates, primary alcohol ethoxylates, fatty acid ethoxylates, alkanolamide ethoxylates, fatty amines. nethoxilates, EO / PO block copolymers and alkyl polyglucosides. Examples of cationic or amphoteric emulsifiers used are: quaternized aminal alkoxylates, alkylbetaines, alkylamidobetaines and sulfobetaines. Typical protective colloids which can be used, inter alia, in suspension polymerization are, for example, cellulose derivatives, polyethylene glycol, polypropylene glycol, copolymers of ethylene glycol and propylene glycol, polyvinyl acetate, polyvinyl alcohol, polyvinyl ether, starch and starch derivatives, dextran, polyvinylpyrrolidone, polyvinylpyridine, polyethyleneimine, polyvinylimidazole , Polyvinylsuccinimid, polyvinyl-2-methylsuccinimide, polyvinyl-1, 3-oxazolidone-2, polyvinyl-2-methylimidazoline and maleic acid or maleic anhydride containing copolymers.

The emulsifiers or protective colloids may e.g. in amounts of from 0.05 to 20 parts by weight per 100 parts by weight of monomers.

Preferably, the process is carried out without the use of emulsifiers or protective colloids. The resulting polymer is therefore preferably dissolved or self-dispersed in the solvent. The resulting polymer solution or polymer dispersion can, for. B. be used as a coating agent. The coating compositions may be, for. For example, protective coatings (such as anticorrosive coatings or weather-resistant coatings), paints, coatings such as decorative coatings (high-gloss coatings), adhesive formulations, textile or paper coatings or preparations for the treatment of leather.

In principle, the solvent can be exchanged before the use of the polymer solutions or polymer dispersions; Also, the polymer solutions or polymer dispersions can be diluted by the addition of further solvents.

However, it is an advantage of the manufacturing process that the solvent used in the manufacturing process, ie NFM, NAM or mixtures thereof, need not be removed or replaced with other solvents before further use. On the contrary, NFM and NAM are very well suited as constituents of coating compositions and are only removed during or after the application of the coating compositions and drying of the coating.

The polymers obtained by the process have a high molecular weight. The molecular weight is generally higher than the molecular weight obtainable with solvents of the prior art under appropriate conditions. This is especially true for polymers made by the process of solution polymerization. The viscosity of the resulting polymer solutions or polymer dispersions is low. The process therefore makes it possible to produce polymer solutions or polymer dispersions with high solids contents. The polymer solutions and polymer dispersions also have high solids contents a sufficiently low viscosity and can therefore be processed well. In particular, the low viscosity causes a very good flow and very good distribution of the coating compositions on surfaces to be coated.

example

Preparation of a Polyacrylate in NFM 180 g of N-formylmorpholine as solvent were introduced into a 1 L three-necked flask with KPG stirrer and 250 ml dropping funnel and a Dimroth cooler, and the mixture was heated to 160.degree.

219.2 g of methyl methacrylate, 105 g of n-butyl acrylate, 63 g of 2-hydroxyethyl methacrylate, 32.8 g of acrylic acid, 8.4 g of Trigonox® B and 16.8 g of Trigonox 21 were mixed in a beaker. Trigonox B (di-ferric butyl peroxide) and Trigonox 21 (ferric butyl peroxy 2-ethylhexanoate) are polymerization initiators from Akzo Nobel.

The mixture was added dropwise over a period of 4 hours. After the addition, the mixture was stirred at 160 ° C. for 1.5 hours.

The solids content of the resulting solution was determined by drying 1 g of substance over a period of 30 minutes at 150 ° C in a convection oven. The solids content was 78% by weight.

Thus, a 78% solution of the polymer in NFM was obtained. The organic polymer solution could also be converted into an aqueous solution. To this was added triethanolamine to convert the acid groups to the appropriate salt groups and diluted to 50% with water.

Comparative example

The example was repeated except that the solvent N-formylmorpholine was replaced by the same amount of butyl glycol. Determination of the molecular weight

The molecular weight of the polymers obtained was determined by GPC (gel permeation chromatography).

Only the molecular weight of the dissolved polymer was determined. Undissolved gel fractions were previously separated by filtration.

As a standard, polymethylmethacrylate (PMMA) was used; it was a narrowly distributed PMMA standard from the company PSS (Polymer Standard Service) with molecular weights from M = 800 to M = 1,820,000. The eluent used was dimethyl acetate + 0.05% trifluoroacetic acid + 0.5% LiBr. The column temperature was 35 ° C; the flow rate was 1 milliliter per minute. The following weight-average molecular weights (Mw) and number-average molecular weights (Mn) of the polymers obtained were determined:

Example: Mn = 3080 g / mol, Mw = 6340 g / mol Comparative example: Mn = 2640 g / mol, Mw = 4830 g / mol

Claims

claims

1 . Process for the preparation of polymers by free-radical polymerization of monomers in a solvent, characterized in that a maximum of 10% by weight of the monomers are monoethylenically unsaturated dicarboxylic acids or derivatives thereof, and

the solvent N-formylmorpholine (short NFM), N-acetylmorpholine (short NAM) or mixtures thereof.

2. The method according to claim 1, characterized in that it is at least 5 wt.% Of the monomers are hydrophilic monomers which are selected from those having an acid group, which may optionally also be present as a salt having a hydroxyl group, with a nitrile group with an amino group, which may optionally also be in the form of a salt, with an amide group, with a lactam group or with an epoxy group.

3. The method according to claim 1 or 2, characterized in that it is at least 20 wt.% Of the monomers are hydrophilic monomers which are selected from those having an acid group, which may optionally also be present as a salt, or with a hydroxyl group.

4. The method according to any one of claims 1 to 3, characterized in that at least 20 wt.% Of the monomers are hydrophilic monomers which are selected from C1 to C10 hydroxyalkyl (meth) acrylates, (meth) acrylic acid or their mixtures.

5. The method according to any one of claims 1 to 4, characterized in that it is at least 60 wt.% Of all monomers of the monomer mixture are monomers having a (meth) acrylic group.

6. The method according to any one of claims 1 to 4, characterized in that it is the monomers to a monomer mixture of a) 0 to 10 wt.% Dicarboxylic acid monomers,

b) from 20 to 100% by weight of hydrophilic monomers

c) 0 to 80 wt.% Of a) and b) various other monomers.

7. The method according to any one of claims 1 to 7, characterized in that the polymer obtained is dissolved or self-dispersed in the solvent.

8. The method according to any one of claims 1 to 7, characterized in that the solvent is at least 30 wt.% Of NFM, NAM or mixtures thereof.

9. The method according to any one of claims 1 to 8, characterized in that it is the solvent is a solvent mixture, which in addition to NFM or NAM also

1, 2 contains propylene carbonate.

10. Use of the polymer solutions obtained by the above process according to any one of claims 1 to 9 or polymer dispersions as coating compositions.

1 1. Use according to claim 10, characterized in that the solvent used in the preparation of the polymers according to any one of claims 1 to 9 is not removed before use.