EP1399508A2

EP1399508A2 - Copolymer/polyol fine-rubber blends by reactive processing with phenol-aldehyde condensate

Info

Publication number: EP1399508A2
Application number: EP02754583A
Authority: EP
Inventors: Werner Obrecht; Norbert Steinhauser; Mario Vierle; Oskar Nuyken
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 2001-06-06
Filing date: 2002-05-24
Publication date: 2004-03-24
Also published as: WO2002098973A2; AU2002321034A1; JP2004527644A; WO2002098973A3; KR20040006018A; CN1514854A; US20040162390A1; DE10127402A1

Abstract

The invention relates to blends of a copolymer and a polyol fine-rubber with very good mechanical properties, obtainable by single-step melt compounding. The invention also relates to a method for the production thereof and to the use thereof in the production of shaped bodies.

Description

Copolymer / polyolefin rubber blends through reactive processing with phenol-aldehyde condensate

The present invention relates to blends of a copolymer and a polyolefin rubber which are obtainable by single-stage melt compounding and have very good mechanical properties, a process for their preparation and their use for the production of moldings.

Copolymer / rubber blends are produced in order to achieve improvements in the mechanical properties of the corresponding materials compared to the pure components. Depending on the blend composition, rubber-modified thermoplastics or thermoplastic elastomers are obtained. Appropriate materials are used in the areas of household, electrical / electronics, automotive, medical technology.

The production of copolymer / rubber blends, e.g. AES (SAN / EP (D) M blend), is carried out according to the solution, emulsion or melt mixing process. In the solution process and emulsion process, radical copolymerization of styrene and acrylonitrile monomers takes place in the presence of dissolved or emulsified rubber. In addition to the formation of styrene-acrylonitrile copolymer, styrene-acrylonitrile copolymer chains are also grafted onto the rubber. These graft copolymers act as phase mediators in the SAN / rubber blend and are necessary in order to achieve a morphology and phase binding of the rubber particles dispersed in the SAN matrix which are advantageous for the blend properties. A disadvantage of such processes is the need to remove the solvent or the emulsion medium, which is associated with a greater outlay in terms of process technology or the production of waste water.

In the melt mixing process, the SAN / rubber blend is produced without a solvent or emulsion medium above the glass transition or melt temperature of the components in a kneader or extruder. To set a morphology and phase connection that is favorable for the product properties, a phase mediator must also be available here. This phase mediator must either be added separately during the blend production or must be formed in situ during the blend production. The separate addition of a phase mediator has the disadvantage that it has to be synthesized in an upstream production step.

The phase mediator can be produced in situ by using functionalized blend components which react with one another to form graft or block copolymers during the blend manufacture. For example, maleic anhydride-functionalized EPDM with NH ₂ -functionalized SAN can be converted into SAN-EPDM graft copolymer, which acts as a phase mediator in the blend (described, inter alia, in C. Pagnoulle, R. Jerome, Polymer 2001, 42, 1893). Here too there is the disadvantage that the functionalized blend components have to be produced separately. The same applies to the method described in US-A 4,278,572. Here, in an upstream synthesis step, polyolefins are reacted with phenol-formaldehyde condensates (methylolphenol oligomers) in the presence of a Lewis acid to give methylolphenol-modified polyolefins. The use of EPDM as a polyolefin component is expressly excluded, since EPDM reacts with phenol-formaldehyde condensate in the presence of a Lewis acid with crosslinking. These methylolphenol-modified polyolefins are then reacted with a second blend component to the desired blend in the next synthesis step. The disadvantage of this method is that two synthesis steps are required for producing the blend and that SAN / polyolefin rubber blends in which the polyolefin rubber contains at least one diene component, such as EPDM, cannot be produced in this way are.

It has now surprisingly been found that copolymer / polyolefin rubber blends can be obtained in only one synthesis step by melt mixing the copolymer and

Polyolefin rubber with the addition of small amounts of a phenol-aldehyde condenser sats and a Lewis acid can be produced, commercially available, not separately functionalized copolymer and polyolefin rubber types can be used and also those polyolefin rubbers which contain a diene component (such as EPDM) can be used. The copolymer / polyolefin rubber blends produced in this way have significantly better mechanical properties than copolymer / polyolefin rubber blends which are produced without the addition of phenol-aldehyde condensate and Lewis acid.

The present invention thus relates to copolymer / polyolefin rubber blends obtainable by compounding the following components:

A) one or more copolymers and

B) one or more polyolefin rubbers, the weight ratio of A to B being between 40: 1 and 1:40, preferably 10: 1 to 1:10, particularly preferably

5: 1 to 1: 5, and

C) 0.25 to 5% by weight, preferably 0.5 to 2.5% by weight, based on the total amount, of a phenol-aldehyde condensate and

D) 0.05 to 2% by weight, preferably 0.1 to 1% by weight, particularly preferably 0.15 to 0.5% by weight, based on the total amount, of a Lewis acid.

Suitable copolymer component A) are copolymers of styrene and acrylonitrile in a weight ratio of 95: 5 to 10:90, preferably 80:20 to 60:40, styrene and / or acrylonitrile being wholly or partly by methylstyrene and / or methyl methacrylate can be replaced; optionally up to 30% by weight (based on component A)) of another monomer selected from the group comprising maleic anhydride, maleimide, N- (cyclo) -alkylmaleinimide, N- (alkyl) -phenylmaleimide can also be used. Suitable styrene-acrylonitrile copolymers have sufficiently high molecular weights to develop thermoplastic properties, preferably they are between approximately 40,000 and 200,000 g / mol, particularly preferably between 50,000 and 150,000 g / mol, determined by means of gel permeation chromatography (GPC).

Details of the preparation of these copolymers are described, for example, in DE-A 2420358 and DE-A 2 724360. Copolymers prepared by bulk or solution polymerization and by suspension polymerization have proven particularly useful.

Suitable polyolefin rubbers B) can be completely amorphous or partially crystalline and can be composed of one or more monomers. Monomers for the production of these polyolefin rubbers are, for example, ethene, propene, linear and branched 1-alkenes having 4 to 12 carbon atoms, cyclopentene, cyclooctene, styrene, methylstyrene, norbornene, conjugated dienes such as isoprene and

Butadiene, non-conjugated dienes with 5 to 25 carbon atoms such as penta-l, 4-diene, hexa- 1,4-diene, hexa-l, 5-diene, 2,5-dimethylhexa-l, 5-diene, 7-methyl-l, 6-octadiene, 1,7-octadiene and octa-l, 4-diene, cyclic dienes such as cyclopentadiene, cyclohexadienes, cyclooctadienes and dicyclopentadiene, and alkenylnorbornenes such as 5-vinyl-2-norbornene, 5-ethylidene-2 -norbornene, 5-butylidene-2-norbornene, 2-methallyl-5-nororbornene and 2-isopropenyl-5-norbornene as well as tricyclodienes such as 3-methyl-tricyclo- (5.2.1.0.2.6) -3,8-decadiene or mixtures thereof are used.

Preferred diene monomers for the production of the polyolefin rubbers are hexa- 1,5-diene, 5-ethylidene norbornene. 5-vinyl-2-norbornene, butadiene, isoprene and dicyclopentadiene. The diene content of the rubbers is generally 0.5 to 50, preferably 1 to 12% by weight, particularly preferably 2 to 8% by weight, based on the total weight of the rubber. Examples of suitable polyolefin rubbers are polybutadiene (BR), polyisoprene, polyisobutene, isobutene-isoprene rubber (IIR), ethene-propene rubber (EPM) and ethene-propene-diene rubber (EPDM).

Preferred polyolefin rubbers are ethene-propene (EPM) and ethene-propene

Diene (EPDM) rubbers.

Also suitable as polyolefin rubbers are block polymers with rubber-elastic properties, in particular, for example, two- (A-B) and three-block copolymers (A-B-A). Block copolymers of type A-B and A-B-A, the typical

Show behavior of thermoplastic elastomers. Preferred block copolymers of the types A-B and A-B-A contain one or two vinylaromatic blocks (preferably based on styrene) and a rubber block (preferably a diene-rubber block, in particular polybutadiene block or polyisoprene block). Suitable block copolymers of types A-B and A-B-A are e.g. described in US

A 3,078,254, US-A 3,402,159, US-A 3,297,793, US-A 3,265,765, US-A 3,594,452 and GB-A 1 264 741. Examples of typical block copolymers of the type AB and AB-A are polystyrene-polybutadiene, polystyrene-poly (ethylene -propylene), polystyrene-polyisoprene, poly- (α-methylstyrene) -polybutadiene, polystyrene-polybutadiene-polystyrene, polystyrene-poly (ethylene-propylene) -polystyrene, polystyrene-polyisoprene-polystyrene and poly- (α-methylstyrene) -Polybutadiene-poly- (α-methylstyrene) and block copolymers in which the olefinic double bonds of the polybutadiene or polyisoprene block are partially or completely hydrogenated. Is preferred among these styrene-butadiene chewable ^'Schuk (SBR).

Suitable phenol-aldehyde condensates C) (methylolphenol oligomers) are obtained by condensing unsubstituted phenol or phenol substituted with linear or branched alkyl or halogen substituents, preferably p- (1,1,3,3-tetramethyl-butyl) phenol an aliphatic or aromatic aldehyde, preferably formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde or benzaldehyde, particularly preferably formaldehyde. The phenol alde hyd condensates contain mixtures of methylolphenol oligomers with up to 20 benzene rings. Examples of suitable compounds are described in US-A 2,972,600, US-A 3,093,613, US-A 3,211,804, US-A 3,287,440 and US-A 3,709,840. Condensates of branched alkyl-substituted phenol and formaldehyde are particularly preferred.

As the Lewis acids D) is metal and transition metal halides are suitable, such as BF _3, BC1 _3, SnCl _2, SnCl _4, ZnCl _2, ZnBr _2, TiCl _3, TiCl _4, A1C1 _3, FeCl _2, FeCl _3, FeBr ₂ , AICI ₃ , AlBr ₃ . Suitable Lewis acids are also described in US-A 4,121,026. Likewise, the corresponding metal oxides or hydroxides can be used in conjunction with a suitable halogen donor, such as polychloroprene or PVC, which forms Lewis acids in situ during melt mixing. Tin, zinc halides, in particular SnCl and ZnCl _{2, are} preferred.

The blend preparation can be carried out using any apparatus which is suitable for producing polymer mixtures, such as e.g. Kneaders, extruders, rollers or combinations thereof. The order of adding the components during the blend production is arbitrary. Preferably, however, the component that makes up the largest proportion of the blend, i.e. Copolymer or polyolefin rubber. It is also possible to pre-mix two or more components before the actual blend is made. The temperature during the production of the blend should be above the melting temperature or glass transition temperature of the main components. A temperature range from 140 to 240 ° C. is preferred, particularly preferably between 160 and 220 ° C. The total mixing time and the time between the addition of individual components should be chosen so that sufficient mixing can take place and is generally from 1 to about 10 minutes.

The reaction is usually stopped by cooling. With this procedure it cannot be ruled out that acid-catalyzed aging reactions take place. For this reason, it is advisable to use the acid or Lewis acid in the neutralize the end of the Inorganic or organic acid scavengers can be used for this. Suitable inorganic acid scavengers are, for example, metal oxides such as calcium oxide, magnesium oxide, zinc oxide or lead oxide. Organic acid scavengers are organic bases such as primary, secondary or tertiary amines, acetates, carboxylates. Capped amines such as carbamates are also suitable. Of

Amides, polyamides, ureas, thiohara substances and guanidine are also suitable.

The polymer blends according to the invention can contain further additives, such as, for example, agents against heat decomposition, agents against heat crosslinking, agents against damage by ultraviolet light, plasticizers, flow and processing aids, flame-retardant substances, lubricants and mold release agents, nucleating agents, antistatic agents, stabilizers and dyes and pigments contain.

The blends according to the invention are suitable for the production of moldings

Extrusion or injection molding.

Examples

components

A) SAN M 60 (styrene-acrylonitrile copolymer, Bayer AG Leverkusen, Germany)

B / l) EPT 2370 (EPDM with an ethylidene norbornene content of approx.

3.0% by weight, Bayer AG Leverkusen, Germany) B / 2) EPT 2070 (EPDM with an ethylidene norbornene content of approx. 0.6% by weight, Bayer AG Leverkusen, Germany) B / 3) EPT 6650 (EPDM with an ethylidene norbornene content of approx.

6.5% by weight, Bayer AG Leverkusen, Germany)

C) Phenol-formaldehyde condensate type Resin SP-1045 (Schenectady Europe Ltd., GB)

D) SnCl ₂ • 2H ₂ O z. Synth. (Merck KGaA, Darmstadt, Germany)

example 1

28.3 g EPDM (type EPT 2370) and 0.9 g phenol are placed in the mixing chamber of a Haake Rheocord System (kneading chamber Rheomix 600p with cam rotors, effective chamber volume 78 cm ³ ), preheated to 140 ° C.

Given formaldehyde condensate. At a rotor speed of 100 revolutions per minute, kneading takes 3.5 minutes. 28.3 g of SAN are then added and the mixture is kneaded for a further 2 min. Then 120 mg of SnCl • 2H ₂ O are added and kneaded for 5 min. The temperature rises to 205 ° C. Finally, the product is removed from the mixing chamber, pressed into a plate on a hot plate, and standard bars are punched out for tensile / strain measurements. The values of breaking energy, tensile stress and elongation at break are determined in accordance with DIN 53504.

The blend preparations for Examples 2 to 6 are carried out in a corresponding manner. The results are summarized in Table 1. Table 1

The examples in Table 1 show that using the phenol-aldehyde condensate in the preparation of the blend significantly better values for the breaking energy and elongation at break are achieved compared to those blends which were produced without using the phenol-aldehyde condensate. These better values for breaking energy and elongation at break are achieved using EPDM types which have a very low (example 2), a medium (example 1) and a high (example 3) diene content.

Claims

Patentansprtiche

1. Polymer blends available by compounding the following components:

A) one or more copolymers and

B) one or more polyolefin rubbers, the weight ratio of A to B being between 40: 1 and 1:40, and

C) 0.25 to 5 wt .-%, based on the total amount of the polymer blend, a phenol-aldehyde condensate and

D) 0.05 to 2% by weight, based on the total amount of the polymer blend, of a Lewis acid.

2. Polymer blend according to claim 1, wherein the weight ratio A) to B) is between 10: 1 and 1:10.

3. Polymer blend according to claim 1 or 2, wherein the proportion of the component

C) 0.5 to 2.5 wt .-%, based on the total amount.

4. Polymer blend according to one or more of the preceding claims, wherein the proportion of Lewis acid D) 0.1 to 1 wt .-%, based on the total amount.

5. Polymer blend according to one or more of the preceding claims, wherein component A) is a copolymer of styrene and acrylonitrile, wherein styrene and / or acrylonitrile can be replaced in whole or in part by α-methylstyrene and / or methyl methacrylate and 0 to 30% by weight. % (based on A) of a further monomer selected from the group containing Maleic anhydride, maleimide, N- (cyclo) -alkylmaleinimide and N- (alkyl) -phenylmaleimide may be included.

6. Polymer blend according to one or more of the preceding claims, wherein component C) is a condensate of alkyl-substituted phenol and

Is formaldehyde.

7. Polymer blend according to one or more of the preceding claims, wherein the Lewis acid D) is SnCl ₂ or ZnCl ₂ or a mixture thereof.

8. Process for the preparation of polymer blends, wherein

A) one or more copolymers and

C) 0.25 to 5 wt .-% based on the total amount of a phenol-aldehyde condensate and

D) 0.05 to 2% by weight, based on the total amount of a Lewis acid,

can be compounded at 140 to 240 ° C.

9. Use of polymer blends according to claims 1 to 7 for the production of

Moldings.

10. Moldings obtainable from polymer blends according to claims 1 to 7.