DE3943111A1 - METHOD FOR PRODUCING CROSSLINKED POLYMERS - Google Patents

Abstract

The new polymers are made by reacting poly-N-acylalkylene imines in which at least some of the N-acyl groups have hydroxyl group substituents with reagents having several groups capable of reacting with hydroxyl groups. Polyisocyanates and aminoplast precondensates are suitable reagents. The new polymers can be used as materials and coatings for hard surfaces.

Description

The invention relates to a new method for producing crosslinked Linear hydroxyl-containing polymer Polymers and new hydroxyl-containing polymers as Starting materials for this process.

Crosslinked polymers are used today in many areas of technology, for example as materials (thermosets, rubber), as coating agents and used as carrier materials (gelling agents). Crosslinked polymers of this type can have a wide variety of substance classes belong, whereby there are essentially two construction principles distinguish: On the one hand, there is the possibility the polymer networks in one step from low molecular weight To establish connections, on the other hand you can already prefabricated linear polymers and use suitable crosslink multifunctional reagents or otherwise.

Although already networked for many applications Polymers are available, efforts continue to be made to find new polymers that have similar or different properties have and which are easy to manufacture on a technical scale to let.

It has been found that new valuable cross-linked polymers can be found can get if you carry certain hydroxyl groups soluble polyalkyleneimines crosslinked in a suitable manner.

The invention relates to a method for producing crosslinked Polymer where one reagent has several to react  has groups capable of hydroxyl groups, with a soluble Poly-N-acylalkyleneimine, in which at least part of the N-acyl groups hydroxyl groups as substituents, to the reaction brought.

Poly-N-acylalkyleneimines are understood to mean polymers of the general Formula A

which are principally obtained by acylation of polyalkyleneimines Have carboxylic acids or carboxylic acid derivatives represented (y = integer). However, it is more common to use cationic ones Polymerization of cyclic imino ethers of the formula B.

wherein the alkylene group is generally an optionally substituted one Chain of 2 or 3 carbon atoms. This cyclic Iminoethers are also called δ-2-oxazolines or 5,6-dihydro-4H-oxazines designated, and consequently for the polymers also the term polyiminoether (polyoxazolines or polyoxazines) introduced.

Soluble poly-N-acylalkyleneimines are now used for the process according to the invention which carry hydroxyl groups in the radical R 'or in some of these radicals. They can be obtained, for example, by saponification of poly-N-acylakyleneimines which contain acetoxy groups as substituents in the acyl radical (A. Levy and M. Litt, J. polym. Sci. A1, 6, 1883-1894 (1968) and US 34 83 145). The labeling of these polymers as soluble is to be understood qualitatively and is not restricted to a specific solvent. It is only intended to distinguish these polymers from crosslinked polymers, which are generally not soluble in solvents, but can at most swell. Soluble poly-N-acylalkyleneimines are preferably used, which can be prepared by copolymerization of 1 to 100 mol% of at least one cyclic imino ether of the formula I with 99 to 0 mol% of at least one cyclic imino ether of the formula II, the formulas I and II have the following appearance:
Formula I:

with the following meaning of the abbreviations:
R = alkyl or alkenyl with 1 to 12 carbon atoms, or aryl;
M = direct bond or divalent group with 1 to 12 carbon atoms, selected from alkylene, alkenylene, arylene and alkarylene groups, which may optionally contain ether oxygens in their chain, where R and M are represented by further hydroxyl groups and / or by Alkoxy groups can be substituted with 1 to 3 carbon atoms;
Z = direct bond or the group CR⁵R⁶;
R¹ to R⁶ = each independently of the other H, alkyl or aryl having 1 to 8 carbon atoms;
Formula II:

with the following meaning of the abbreviations:
R⁷ = alkyl, alkenyl, aryl, alkaryl with 1 to 21 C atoms or the group R⁸-O- (CH₂CH₂O-) _x R⁹- with x = 0 to 2,
R⁸ = C₁-C₃ alkyl, R⁹ = C₁-C₃ alkylene;
Z, R¹-R⁶ = meaning as in formula I, but independently of this.

Poly-N-acylalkyleneimines which are particularly preferred are those which Copolymerization from 15.1 to 100 mol%, in particular 20 to 98 Mol% of at least one cyclic imino ether of the formula I with 84.9 to 0 mol%, in particular 80 to 2 mol% of at least one cyclic imino ether of the formula II can be prepared.

The vast majority of the cyclic iminoethers are known and all according to known methods, for example according to DE 16 70 012, DE 14 45 642 or according to the earlier applications DE-P 39 14 155, P 39 14 133 and EP 8 81 18 090.5 can be produced. Examples for cyclic iminoethers of the formula I are:

2- (2-hydroxypropoxyphenyl) oxazoline
2- (1-hydroxyethyl) oxazoline
2- (2-hydroxypropyl) dihydrooxazine
2- (1-hydroxybutyl) oxazoline
2- (3-hydroxybutyl) dihydrooxazine
2- (1-hydroxypentyl) oxazoline
2- (3-hydroxypentyl) oxazoline
2- (3-hydroxyheptyl) oxazoline
2- (3-hydroxynonyl) oxazoline
2- (α-hydroxybenzyl) oxazoline
2- (4-hydroxyundecyl) dihydrooxazine
2- (1-hydroxy-3-methylbutyl) oxazoline
2- (11-hydroxyheptadecyl) oxazoline
2- (11-hydroxy-9-heptadecenyl) oxazoline
2- (9-hydroxy-10-methoxyheptadecyl) oxazoline
2- [13,14- (Hydroxy, methoxy) heneicosyl] oxazoline

Examples of cyclic imino ethers of the formula II are:

2-ethyloxazoline
2-heptyloxazoline
2- (2-ethylpentyl) oxazoline
2-octyloxazoline
2-nonyloxazoline
2-undecyloxazoline
2-pentadecyloxazoline
2-heptadecyloxazoline
2- (8-heptadecenyl) oxazoline
2- (8,11-heptadecadienyl) oxazoline
2-heptyl-3-methyl-oxazoline
2-phenyl-4-methyl-oxazoline
2-phenyloxazine
2- (4-tert-butylphenyl) oxazoline
2- (4-chlorophenyl) oxazoline
2- (2-oxopropyl) oxazine
2- (2,5-dioxahexyl) oxazoline
2- (2,5,8-trioxanonyl) oxazoline

The polymerization of the imino ethers can also be done in itself known methods take place, for example according to DE 12 06 585, US 34 58 456 or the earlier application DE-P 39 00 859.2. In contrast to the information of US 34 58 456 are used when using Iminoethers of the formula I also in the case of higher molar proportions Polymerization resulting poly-N-acylalkyleneimine is not insoluble.

Are particularly preferred for the method according to the invention Poly-N-acylalkyleneimines derived from such cyclic imino ethers are prepared, in the formula I and / or II at least 4 of the radicals R¹ to R⁶ are hydrogen atoms and the rest of C₁-C₃ alkyl exist. Furthermore in formula I and / or formula  II Z preferably the meaning of a direct bond, i. H. it the monomers are delta-2-oxazolines. Of these in turn, those with the following substitution patterns particularly preferred:

R¹ = CH₃, R²-R⁴ = H
R³ = CH₃, C₂H₅ or phenyl; R¹, R² and R⁴ = H

Poly-N-acylalkyleneimines in which all residues R¹ to R⁶ are hydrogen.

As far as the poly-N-acylalkyleneimines are copolymers acts, these can be done in the usual way by choosing the polymerization conditions with more or less statistical distribution of the monomers in the chain or as block polymers getting produced. All forms are for the invention Suitable method, but the statistical polymers in preferred in most cases. The molecular weight of the poly-N-acylalkyleneimines can be within wide limits, for example between 1000 and 1,000,000, preferably between 3,000 and 50,000 freely chosen will.

The majority of the aforementioned hydroxyl-containing soluble ones Poly-N-acylalkyleneimines have not previously been described. So far, the statement was that a few percent of a cyclic imino ether containing hydroxyl groups in the Crosslink polymerization and therefore insoluble poly-N-acylalkyleneimines lead (US 34 58 456 and A. Levy and M. Litt in J. Polym. Sci A1, 6, 1883-1894 (1894)). However, it turned out that when using certain cyclic imino ethers of formula I soluble Poly-N-acylalkyleneimines are formed. These connections are therefore a separate subject of this invention. It is about are poly-N-acylalkyleneimines which are obtained by copolymerization of 15.1 to 100 mol%, preferably 20 to 98 mol%, of a cyclic  Iminoether of formula I with 84.9 to 0 mol%, preferably 80 to 2 mol% of a cyclic imino ether of the formula II are produced, except polyacylalkyleneimines according to the older application DE-P 39 00 859.2, the 20 wt .-% and more Contain monomer units, the acyl residues of an unsaturated carry aliphatic carboxylic acid with 16 to 22 carbon atoms. Furthermore the explanations given above for the poly-N-acylalkyleneimines apply were made. Regarding the manufacture of the new Connections are particularly based on the information in the older Application DE-P 39 00 859.2 referred to, the disclosure of which in in this regard expressly with the content of the present application is made. Particularly preferred compounds are those the acyl groups of 2-hydroxypropionic acid, 3-hydroxybutyric acid, 4-hydroxyoctanoic acid, 12-hydroxystearic acid or which carry 9,10- (hydroxy, methoxy) stearic acid, as well as those in which R⁷ is an alkyl radical having 1 to 21 carbon atoms, preferably 2 to 17 carbon atoms, or a phenyl radical represents.

The reagents required for crosslinking are Compounds of relatively low molecular weight, the carry at least two functional groups, those with hydroxyl groups can react. Examples of such groups are, for example Anhydride groups and acid chloride groups. The reactivity of this Groups essentially determines the reaction conditions of the Procedure. By the amount of crosslinking reagent related to the degree of crosslinking is determined by the hydroxyl groups present, its upper limit otherwise on the density of the hydroxyl groups is determined in poly-N-acylalkyleneimine.

Preferred crosslinking reagents for the process according to the invention are polyisocyanates and aminoplast precondensates, however phenol-formaldehyde precondensates are also suitable.

The polyisocyanates can be compounds of the formula III act

A (-NCO) _n (III)

in the A an aliphatic, aromatic or araliphatic Group with 4 to 40 C atoms and n free valences at different Represents carbon atoms and n has one of the values 2, 3 or 4. These polyisocyanates are well known in chemical engineering Compounds usually made up of the corresponding amines COCl₂ are produced. They preferably contain in the molecular part A. 6 to 26 carbon atoms. For details, refer to the Information in manuals such as Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, volume 23, p. 586 (1984). As Examples of suitable polyisocyanates are N, N ′, N ′ ′ - tris (omega isocyanatohexyl) biuret; 2,2,4-trimethylhexamethylene-1,6-diisocyanate; 1,6-hexamethylene diisocyanate; 2,4-tolylene diisocyanate; 4,4'- and / or 2,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and called isophorone diisocyanate. Diisocyanates are particularly preferred in the context of the invention. Instead of Polyisocyanates of formula III can so-called with equal success masked polyisocyanates are used. Acting it is adducts with polyisocyanates of the formula III, which at Temperature increase disintegrate with the regression of the polyisocyanates and then enter additions in the same way as the polyisocyanates. So-called prepolymers with isocyanate end groups are also suitable, usually made from long chain alpha, omega diols with average molecular weights of about 500-5000 and excess Diisocyanates of the formula A are prepared.

The reaction between the isocyanates III and the poly-N-acylalkyleneimides runs smoothly for those for the implementation of alcohols with usual isocyanate conditions, that is at temperatures between about room temperature and about 160 ° C and reaction times from about 1 to 10 hours. Depending on the reactivity of the Isocyanates and the alcohol component can meet these conditions but can also be significantly exceeded or fallen short of. The reaction  can be prepared in the presence of suitable aprotic solvents, for example aromatic hydrocarbons, chlorinated hydrocarbons, Carry out esters or ketones, generally under Exclusion of moisture is being worked on. Preferably the Crosslinking made without solvent. For acceleration can be used for the reaction of alcohols with isocyanates usual catalysts, especially tin compounds such as dibutyltin dilaurate or tertiary amines such as 1,4-diazabicyclo- [2,2,2] - octane can be added. The progress of the reaction can be checked Determination of the unreacted isocyanate, for example by reaction with excess dibutylamine in toluene and Follow back titration with HCl.

As a rule, polyisocyanate is no longer used for crosslinking, than for complete reaction with the available hydroxyl groups is required. In many cases, however, it is sufficient a deficit of polyisocyanate, especially if only a low level of crosslinking is intended and / or the end product should still have hydroxyl groups.

In the case of the aminoplast, which are also preferred as crosslinking reagents, Pre-condensates are condensation products from Formaldehyde with various amines, preferably urea and / or melamine, which may be etherified with lower alcohols could be.

Characteristic structural features of these products used in technology Methylene bridges are offered in various forms between amidic nitrogen atoms and those bound to nitrogen Methylol groups and optionally alkoxymethyl groups. In terms of For further details, please refer to suitable manuals, for example Ullmann’s encyclopedia of technical chemistry, 4th edition, volume 7, p. 403 (1974).  

The reaction between the poly-N-acylalkyleneimines and the aminoplast Pre-condensates are preferably solvent-free carried out, however, the mixing of the components first with the help of suitable solvents, for example aromatic Hydrocarbons, or suspending agents, for example Water. The actual cross-linking reaction takes place at higher temperatures, preferably between 100 and 220 ° C and generally lasts 5 to 45 Minutes.

The reaction between the aminoplast precondensates and the Poly-N-acylalkyleneimines do not follow a fixed stoichiometry. The Ratio of reactants can therefore vary depending on the desired properties of the end product can be chosen freely. Are usual with hydroxyl group contents over 15 mol% in Poly-N-acylalkyleneimine weight ratios of 1 to 0.2; prefers 0.7 to 0.25 (each precondensate to poly-N-acyl alkyleneimine), but these values can also be exceeded or exceeded if necessary be undercut.

The end products of the process are highly elastic to hard masses with a low degree of crosslinking Can swell solvents. They are excellent as materials and, if necessary, can also be smooth in shapes getting produced. Their suitability as is also outstanding Coating agent for solid surfaces, where they are resistant and adherent coatings result.

Examples A. Preparation of the hydroxyl-containing poly-N-acylalkyleneimines

Poly-N-acylalkyleneimines suitable according to the invention were obtained by cationic polymerization of cyclic imino ethers of the formula I. and cyclic iminoethers of the formula II in bulk with the addition of methyl p-toluenesulfonate as a catalyst produced. For this, the iminoethers were provided in the Ratio at room temperature or just above it Melting point mixed and then stirring with a small Amount of p-toluenesulfonic acid methyl ester as catalyst added and heated to 160 ° C for 30 minutes. Using of lower boiling point iminoethers was below the Boiling point correspondingly longer, but in any case up to complete implementation polymerized. Tables 1 and 2 give the details of those used for polymerization Iminoethers based on mostly technical carboxylic acids. They became analogous to the information in the earlier patent applications EP 88 118 090.5, DE-P 39 14 133 and DE-P 39 14 155. The polymerizations were generally batch sizes of about 100 g. They delivered at room temperature solid products that without further purification for the inventive methods could be used. The The polymers were characterized by their molecular weight (determined as weight average with the aid of gel permeation chromatography against polystyrene standard). Table 3 gives the details of the polymerizations and the molecular weights of the resulting products again.  

Table 1

Cyclic iminoethers of the formula I.

Table 2

Cyclic iminoethers of the formula II

Table 3

Poly-N-acylalkyleneimienes

B. Crosslinking of the poly-N-acylalkyleneimines with aminoplast precondensates

The crosslinking process was deep drawn in these examples Iron sheets carried out in this way a to produce heat-hardened paint on the metal sheets.

For this purpose, 70% solutions of the poly-N-acylalkyleneimides in toluene or 55% dispersions of these polymers in water in a weight ratio of 7: 3 (based on solvent-free Products) with a melamine resin (type Cymel 301, company American cyanamide) and mixed with a squeegee applied the sheets. The aqueous dispersions were in the way that initially produces 33% solutions of the polymers were prepared in isopropanol, which then with stirring 2.5 times the amount of water (based on polymer) was added were. Isopropanol and water were then removed from the mixture removed under vacuum until a 55% Dispersion in water remained. After the sheets have been vented at room temperature the coated sheets were in one Convection oven heated to 160 ° C for 25 minutes to crosslink the films. The next day the pendulum hardness of the paint films determined according to the German standard DIN 53 157. The results, which are listed in the following Table 1 showed that Films of good hardness had been created.  

Table 1

Networking on iron sheets

C. Crosslinking of the poly-N-acylalkyleneimines with polyisocyanate

This crosslinking reaction was also carried out on reaction mixtures performed on films using a squeegee Iron sheets had been applied to make them sticky in this way To produce coatings. In the examples, the mixture was made up each from equivalent amounts of poly-N-acylalkyleneimine (based on hydroxyl groups) and 4,4'-diphenylmethane diisocyanate (MDI) or a diisocyanate capped with caprolactam (Grillbond IL6 (Ems-Chemie, equivalent weight 238). Crosslinking of the film was done by loading the coated Tin in a convection oven for 25 minutes 160 ° C reached. The next day the properties of the Paint film in the form of the pendulum hardness according to DIN 53 157, the impact recess (reverse) according to US standard ASTM-D 2795-69 and the cross cut after H. J. Peters (in Zeidler-Bleich, Laboratoriumsbuch for the paint and coating industry, p. 309-310, W. Knopp Verlag, Düsseldorf, 1967). Here correspond to higher ones  Numerical values for pendulum hardness and impact depth of a larger one Hardness or better flexibility of the coating. The assessment the cross-cut was made visually with a classification between 0 (best liability) and 4 (poor liability).

Table 2

Networking on iron sheets

Claims (14)

1. A process for the preparation of crosslinked polymers, characterized in that a reagent which has several groups capable of reacting with hydroxyl groups is reacted with a poly-N-acylalkyleneimine in which at least some of the N-acyl groups have hydroxyl groups as substituents becomes. 2. The method according to claim 1, in which a poly-N-acylalkyleneimine is used, which can be prepared by copolymerization of 1 to 100 mol% of a cyclic imino ether of the formula I with 99 to 0 mol% of a cyclic imino ether of the formula II, formulas I and II have the following appearance:
Formula I: with R = alkyl or alkenyl having 1 to 12 carbon atoms, or aryl;
M = direct bond or divalent group with 1 to 12 carbon atoms, selected from alkylene, alkenylene, arylene and alkarylene groups, which may optionally contain ether oxygens in their chain, where R and M are represented by further hydroxyl groups and / or by Alkoxy groups can be substituted with 1 to 3 carbon atoms;
Z = direct bond or the group CR⁵R⁶;
R¹ to R⁶ = each H, alkyl or aryl having 1 to 8 carbon atoms;
Formula II: with R⁷ = alkyl, alkenyl, aryl, alkaryl with 1 to 21 C atoms or the group R⁸-O- (CH₂CH₂O-) × R⁹- with × = 0 to 2, R⁸ = C₁-C₃-alkyl, R⁹ = C₁- C₃ alkylene;
Z, R¹-R⁶ = meaning as in formula I, but independently of this. 3. The method according to claim 2, in which in formula I and / or formula II the symbol Z is a direct link. 4. The method according to claim 2, in which in formula I and / or in Formula II R¹ to R⁶ are hydrogens. 5. The method according to any one of claims 1 to 4, in which the Reaction with hydroxyl groups enabled a polyisocyanate, a capped polyisocyanate or a prepolymer Isocyanate end groups. 6. The method according to any one of claims 1 to 4, in which the Reaction with hydroxyl groups enabled an aminoplast Is precondensate. 7. Poly-N-acylalkyleneimine, obtainable by copolymerization of 15.1 to 100 mol% of a cyclic imino ether of the formula I. with 84.9 to 0 mol% of a cyclic imino ether of the formula II, these formulas having the appearance given in claim 2 have, with the exception of poly-N-acylalkyleneimines, 20% by weight and contain more monomer units, the acyl residues of an unsaturated aliphatic carboxylic acid with 16 to 22 carbon atoms wear.   8. poly-N-acylalkyleneimine according to claim 7, can be produced by Copolymerization of 20 to 98 mol% of a cyclic imino ether of formula I with 80 to 2 mol% of a cyclic Iminoethers of the formula II. 9. poly-N-acylalkyleneimine according to one of claims 7 or 8, in which in formula I and / or in formula II, preferably in both, at least 4 of the radicals R¹ to R⁶ are hydrogen atoms are and which incidentally consist of C₁-C₃-alkyl. 10. poly-N-acylalkyleneimine according to one of claims 7 or 8, in which in formula I and / or formula II, preferably in both, Z is a direct bond. 11. poly-N-acylalkyleneimine according to claim 10, in which in formula I and / or in formula II, preferably in both, R¹ to R⁶ Are hydrogen. 12. poly-N-acylalkyleneimine according to one of claims 7 or 8, in which in formula I the group HO-CHR-M- the alkyl group of 2-hydroxypropionic acid, 3-hydroxybutyric acid, 4-hydroxyoctanoic acid, 12-hydroxystearic acid or 9,10- Represents (hydroxy, methoxy) stearic acid. 13. poly-N-acylalkyleneimine according to one of claims 7 or 8, in which in formula II R⁷ an alkyl radical with 1 to 21 C atoms, preferably with 2 to 17 C atoms, or one Represents phenyl radical. 14. poly-N-acylalkyleneimine according to one of claims 7 or 8, with an average molecular weight of 1,000 to 1,000,000, preferably 3,000 to 50,000.