DE102005022452A1 - Preparation of thermoplastic elastomer comprises providing a polycondensate, providing a soft component such as polyether or polyester, which contains isocyanate groups and reacting the polycondensate with the soft component - Google Patents

Abstract

Preparation of thermoplastic elastomer comprises: providing a polycondensate which has reactive groups such as amine or hydroxy, providing a soft component such as polyether or polyester, which contains isocyanate groups and reacting the polycondensate with the soft component in a solution or a melt. An independent claim is also included for a thermoplastic elastomer produced by the above process.

Description

The The invention relates to a process for the preparation of new thermoplastic Elastomers with polymeric or oligomeric polycondensate hard segments and polyether and / or polyester soft segments. Subject of the Invention are also the thermoplastic produced by this method Elastomers.

thermoplastic Elastomers made from polycondensate hard segments and soft segments are known, are known, for example Polyetheresteramide (DE-A-25 23 991, DE-A-27 12 987), polyetheramides (DE-A-30 06 961) and polyether esters (DE-A-22 13 128). Such elastomers can either by direct condensation in a stirred tank starting from polyamide or polyester-forming monomers, a chain regulator and a Polyether diol or diamine or by polymer analog Implementation of preformed hard and soft blocks. A disadvantage of this method is, however, that polyester blocks as well as, even stronger pronounced, polyether thermally not very stable, so that in particular at higher reaction temperatures and / or longer Reaction times decomposition reactions occur, leading to chain scission to lead and thus ultimately limit the achievable molecular weight.

One Another process especially for the production of polyamide elastomers is in EP-A-1 219,652. There are activated soft segments on the anionic lactation polymerized hard segments that are reactive over Reaction can be condensed quickly to polyamide elastomers. This However, the process is limited to elastomers whose polyamide hardblock is derived from a lactam.

The In contrast, the object of the present invention is thermoplastic elastomers containing polycondensate hard blocks, in a big one Variation width available whereby the reaction can be carried out so gently that secondary reactions, which damage the end groups or split the chains, as far as possible suppressed.

• a) Bereitstellung eines Polykondensats, das reaktive Gruppen trägt, die ausgewählt sind aus -NH₂ und -OH
• b) Bereitstellung einer Weichkomponente, ausgewählt aus Polyether und Polyester, die Isocyanatgruppen trägt,
• c) Umsetzung des Polykondensats mit der Weichkomponente in Lösung oder Schmelze.

This object is achieved by a process for producing a thermoplastic elastomer, which comprises the following steps:

• a) providing a polycondensate bearing reactive groups selected from -NH ₂ and -OH
• b) providing a soft component selected from polyether and polyester bearing isocyanate groups,
• c) reaction of the polycondensate with the soft component in solution or melt.

In a preferred embodiment sit the reactive groups of the polycondensate and / or the isocyanate groups the soft component at the chain ends.

The polycondensate carrying the reactive groups generally has a number average molecular weight M _n in the range of 500 to 10,000, preferably in the range of 1,000 to 6,000, and more preferably in the range of 1,500 to 5,000, while the isocyanate group-carrying soft component in general has a number average molecular weight in the range of 300 to 10,000, preferably in the range of 500 to 5,000, and more preferably in the range of 600 to 3,000. In this respect, polycondensate and soft component are present as prepolymers.

The Polycondensate may for example be a polyamide, a polyester Polyesteramide or a polycarbonate.

When Polyamide are primarily aliphatic homo- and copolycondensates in question, for example PA 46, PA 66, PA 68, PA 610, PA 612, PA 614, PA 410, PA 810, PA 1010, PA 412, PA 1012, PA 1212, PA 6, PA 7, PA 8, PA 9, PA 10, PA 11 and PA 12. (The labeling of the polyamides corresponds to international standard, where the first digit (s) is the C atomic number of the starting diamine and the last digit (s) is the C atomic number of the dicarboxylic acid specify. If only one number is mentioned, this means that from an α, ω-aminocarboxylic acid or it has been assumed that the lactam derived therefrom; by the way referred to H. Domininghaus, The Plastics and Their Properties, Pages 272 ff., VDI-Verlag, 1976.)

Provided a copolyamide is used, this may e.g. Adipic acid, sebacic acid, suberic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, etc. as a co-acid or bis (4-aminocyclohexyl) methane, trimethylhexamethylenediamine, Hexamethylenediamine or the like contained as codiamine. Lactams such as caprolactam or laurolactam or aminocarboxylic such as ω-aminoundecanoic acid as Cocomponent also be incorporated.

When the reactive groups of the polyamide are NH ₂ groups, these prepolymers can be prepared by direct reaction of the polyamide-forming monomers in the presence of a diamine excess. Alternatively, first a high molecular weight polyamide can be prepared, the then degraded to the prepolymer by reaction with a diamine, preferably in the melt.

polyamides, which contain OH groups as reactive groups, can be advantageously starting from COOH-containing polyamides by the COOH groups with a surplus a diol, for example ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol. Alternatively, you can the COOH groups too with an epoxide such as e.g. Ethylene oxide, propylene oxide, phenyl glycidyl ether or implement the like.

thermoplastic Polyesters are prepared by polycondensation of diols with dicarboxylic acids or their polyester-forming derivatives, such as dimethyl esters produced. Suitable diols have the formula HO-R-OH, where R is a divalent, branched or unbranched aliphatic and / or cycloaliphatic Radical with 2 to 40, preferably 2 to 12, carbon atoms. Have suitable dicarboxylic acids the formula HOOC-R'-COOH, where R 'is a divalent one aromatic radical having 6 to 20, preferably 6 to 12, carbon atoms means.

As an example of diols are ethylene glycol, trimethylene glycol, tetramethylene glycol, 2-butenediol-1,4, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol and the C ₃₆ diol called dimerdiol. The diols can be used alone or as a diol mixture.

When aromatic dicarboxylic acids come for example terephthalic acid, isophthalic acid, 1,4-, 1,5-, 2,6- or 2,7-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid and Diphenyl ether-4,4'-dicarboxylic acid in question. Up to 30 mol% of these dicarboxylic acids can by aliphatic or cycloaliphatic dicarboxylic acids having 3 to 50 carbon atoms and preferably with 6 to 40 C atoms, such as. Succinic acid, adipic acid, sebacic, dodecanedioic, brassylic tetradecanedioic or cyclohexane-1,4-dicarboxylic acid, be replaced.

Examples for suitable Polyesters are polyethylene terephthalate, polypropylene terephthalate, Polybutylene terephthalate, polyethylene-2,6-naphthalate, polypropylene-2,6-naphthalate and polybutylene-2,6-naphthalate.

The Production of these polyesters belongs to the prior art (DE-OSS 24 07 155, 24 07 156; Ullmann's Encyclopedia of technical chemistry, 4th edition, volume 19, pages 65 ff., Verlag Chemie, Weinheim, 1980).

Polyester, which contain as reactive groups OH groups can be, for example, by direct reaction of the polyester-forming monomers in the presence a diol surplus produce.

alternative this can also be first made of a high molecular weight polyester, which is then through Reaction with a diol, preferably in the melt, to the prepolymer is reduced. On the other hand, you can also analogous to a Polyester go out containing COOH groups, and then by reaction with a diol or an epoxide as described above for the polyamide, implement so that an OH group results.

The same applies to Polyester.

wobei R'' einen zweiwertigen Rest mit 2 bis 4 C-Atomen bedeutet und A eine isocyanattragende Gruppe darstellt. n wird so gewählt, dass der Isocyanatgruppen tragende Polyether das oben für die Weichkomponente angegebene Molekulargewicht besitzt. Derartige Polymere werden in der Regel durch Umsetzung eines Polyetherdiols oder Polyetherdiamins mit einem Diisocyanat hergestellt, wobei die Isocyanatgruppen frei oder in blockierter Form vorliegen können. Polyetherdiole und Polyetherdiamine sind bekannt und in vielen Typen im Handel verfügbar.The soft component is a polyether or a polyester. Suitable polyethers have the general formula

wherein R "represents a bivalent radical having 2 to 4 carbon atoms and A represents an isocyanate-bearing group. n is chosen so that the isocyanate group-carrying polyether has the molecular weight given above for the soft component. Such polymers are generally prepared by reacting a polyether diol or polyether diamine with a diisocyanate, wherein the isocyanate groups may be free or in blocked form. Polyether diols and polyether diamines are known and commercially available in many types.

The Reaction of the polyether diol or polyether diamine with the diisocyanate will be in solution or Melt carried out, wherein preferably per functional group at least 0.7 diisocyanate molecules used becomes. If you use less, chain extension reactions come to the fore, which may also be purposefully brought about can be. If you use more than one molecule per functional group, you must the diisocyanate excess subsequently be removed, if one chain extension reactions in the Exclude hard component want. The upper limit is usually 1.3.

The Isocyanate groups of the diisocyanates used are in an embodiment Blocked implementation with suitable blocking agents.

The blocking is described, for example, in ZW Wicks, Jr., Progress in Organic Coatings 3 (1975), Pages 73 to 99 and in ZW Wicks, Jr., Progress in Organic Coatings 9 (1981), pages 3 to 28. The known blocking agents which undergo an addition reaction at 20 to 120 ° C with isocyanate groups, which at higher temperatures reversible is such that the then released isocyanate groups can react with reactive groups of a polyol. Suitable blocking agents are, for example, secondary or tertiary alcohols, phenols, CH-acidic compounds (such as malonic acid derivatives), lactams (for example ε-caprolactam) and oximes. Preferred blocking agents are oximes, such as formaldoxime, acetaldoxime, cyclohexanone oxime, acetophenone oxime, benzophenone oxime, and especially methyl ethyl ketoxime. Other useful blocking agents are 3,5-dimethylpyrazole and 1,2,4-triazole. In addition, blocking can also be done by forming a uretdion.

Suitable polyesters suitable as the soft component are those of a substantially aliphatic nature. They can be prepared either from a C ₂ - to C ₄₄ -diol and a C ₂ - to C ₄₄ -dicarboxylic acid or from a C ₆ - to C ₂₀ -lactone. Examples which may be mentioned are: polyethylene adipate, polytetramethylene adipate, polytetramethylene sebacate, polyhexamethylene sebacate, polytetramethylene dodecanedioate, polycaprolactone and polylaurolactone.

The Reaction of the reactive polycondensate (hard component) with the Soft component to the thermoplastic elastomer may be in solution or Melt carried out be, preferably under forced mixing and optionally degassing.

With Help of the invention can be prepared from suitable prepolymers via a reactive process, e.g. reactive extrusion, thermoplastic Producing elastomers of various structures and properties. At the same time, thermoplastic elastomers with polyester soft segments are accessible, which can not be produced by direct polycondensation and the across from Elastomers with polyether soft segments, for example, an improved UV stability exhibit.

In continuation this invention would be then to think about the reactive end groups of the hard component and to swap the soft component. Because of the relatively high Melting points of the prepolymeric polycondensate hard blocks used must in the reaction with the diisocyanate but at such high temperatures be worked that a defined refunctionalization of the reactive Groups is difficult. As far as this succeeds, this procedure is However, the claimed method equivalent and leads to corresponding Products.

The Invention will be exemplified below.

Example 1: Preparation a PA 12 prepolymer with OH terminal groups

In a 250 ml three-necked flask 25.00 g of a high molecular weight PA 12 were weighed and rinsed with pure nitrogen. After addition of 0.5 g of adipic acid dimethyl ester for amino endblocking, the granules were melted at 250 ° C metal bath temperature under nitrogen. With stirring, 4.274 g of adipic acid (29.27 mmol) as a cleavage agent were added to the melt and stirred for 15 minutes. The obtained carboxyl-terminated prepolymer (number-average molecular weight M _n of 1000, 29.3 mmol) was immediately further processed in melt.

To cooling down the melt was at 180 ° C. a micro-distillation column placed on the piston. After that became a solution of 8.80 g of glycidyl phenyl ether (58.6 mmol) in 10 mL of dried N-methylpyrrolidone (NMP) with stirring quickly added to the melt. The approach was still 2 hours touched, the ultrapure nitrogen gassing was interrupted and the NMP was submerged stir distilled off in a water-jet vacuum. The melt was made with pure nitrogen rinsed and further processed directly in Example 3.

Example 2: Preparation an isocyanate-terminated PTHF prepolymer

29,00 g (29 mmol) of a dried OH-terminated PTHF-1000 melted at 80 ° C. and degassed alternately by vacuum and nitrogen. Thereupon were 8.780 g of hexamethylene diisocyanate (52.2 mmol) at 80 ° C with stirring in Substance added quickly and the reaction mixture homogenized. Subsequently the temperature was at 120 ° C elevated. The theoretically calculated NCO concentration becomes under these conditions at 120 ° C reached after about 150 minutes. The reaction became after 3 hours completed; the melt of the prepolymer was used directly in Example 3.

Example 3: Kneader reaction

The chamber of a Haake laboratory kneader was heated to 200 ° C and set a speed of 90 revolutions per minute. The melt of Example 1 was subsequently added to the kneader, followed immediately by the melt of Example 2. 5 minutes after addition of the substances, the chamber temperature was lowered to 150 ° C, opened the chamber and the product entnom men. After solidification, an elastomeric material was present which had filament-forming properties.

Claims (6)

A process for preparing a thermoplastic elastomer comprising the steps of: a) providing a polycondensate bearing reactive groups selected from -NH ₂ and -OH, b) providing a soft component selected from polyether and polyester bearing isocyanate groups, c) reaction of the polycondensate with the soft component in solution or melt. Method according to claim 1, characterized in that the reactive groups of the polycondensate and / or the isocyanate groups of the soft component at the chain ends to sit. Method according to one of the preceding claims, characterized in that the reactive group-carrying polycondensate having a number average molecular weight M _n in the range of 500 to 10,000 and the isocyanate group-bearing soft component has a number average molecular weight M _n in the range of 300 to 10,000. Method according to one of the preceding claims, characterized in that the polycondensate is a polyamide, a Polyester or a polyester amide. Method according to one of the preceding claims, characterized in that the isocyanate groups of the soft component are capped with a blocking agent. Thermoplastic elastomer prepared according to a of the preceding claims.