CA1098237A - Compositions containing hyrogenated block copolymers and engineering thermoplastic resins - Google Patents

Abstract

A B S T R A C T
In a composition containing a partially hydrogenated block copolymer, a polycarbonate and at least one dissimilar engineering thermoplastic resin at least two of the polymers form at least partial continuous interlocked networks with each other.

Description

The invention relates to a composition containing a partially hydrogenated block copolymer comprising at least two terminal polymer bloc~s A of a monoalkenyl arene having an average molecular weight of from 5gOOO to 125,000 and at least one intermediate polymer block ~ of a conjugated diene ha~ing an average molecular weight of from ~0,000 to 300~000, in which the terminal polymer bloclcs A constitute from 8 to 55% by weight of the block copolymer and no more than 25~ of the arene double bonds of the polymer blocks A
and at least 80% Or the aliphatic double bonds of the polymer blocks B have been reduced by hydrogenation.
Engineering thermoplastic resins are a group of polymers that possess a balance of properties comprising strength, stiffness, impact resistance, and long term dimensional stability that make them useful as structural materials.
Engineering thermoplastic resins are especially attractive as replacements for metals because of the reduction in weight that can often be achieved as, for example, in automotive applications.
For a partlcular application, a single thermoplastic resin may not offer the combination of properties desired and, therefore, means to correct this deficiency are of interest~ One particularly appealing route is through blending together two or more polymers (which individually have the properties sought) to give a material with the desired combination of properties. This approach has been .

;~ .

successful in li~ited cases, such as in the improvement of impact resistance for thermoplastic resins, e.g., polystyreneg polypropylene and poly(vinyl chloride), using special blending procedures or additives ~or this purpose. However, in general, blending of thermoplastic resins has not been a successful route to enable one to combine into a single material the desirable individual characteristics of two or more polymers. Instead, it has often been found that such blending results in combining the worst features of each with the result being a material of such poor properties as not to be of any practical or commercial value. The reasons for this failure are rather well understood and stem in part from the fact that thermodynamics teaches that most combinations of polymer pairs are not miscible, although a number of notable e~ceptions are known. More importantly, most polymers adhere poorly to one another. As a result, the interfaces between component domains (a result o~ their immiscibility) represent areas o~ severe weakness in blends and, therefore, provide natural flaws and cracks which result in facile mechanical failure. Because of this~
mos~ polymer pairs are said to be "incompatible". In some instances the term compatibility is used synonymously with miscibility, however, compatibility is used here in a more general way that describes the ability to combine two polymers together for beneficial results and may or may not connote miscibility.

One method which may be used to circumvent this problem in polymer blends is to "compatibilize" the two polymers by blending in a third component, orten referred to as a "compatibi.lizing agent", that possesses a dual solubility nature for the two polymers to be blended.
Examples of this third component are obtained in block or graft copolymers. As a result of thi.s characteristic, this agent locates at the interface between components ~:
and greatly improves interphase adhesion and therefore increases stability to gross phase separati.on.
The i.nvention covers a means to stabilize multi-polymer blends that is independent of the prior art : .
compatibilizing process and is not restricted to the necessity for restrictive dual solubi].ity characteristics.
The materials used for this purpose are special block co-polymers capable of thermally reversible self-cross-linking.
Their action in the present invention is not that visualize~
by the usual compatibilizing concept as evidenced by the general ability of these materials to perform similarly for a wide range of blend components which do not conform to the solubility requirements Or the previous concept.
Now, the invention provides a composition containing a partially hydrogenated block copolymer comprising at least two terminal polymer blocks A of a monoalkenyl arene ~ -having an average molecular weight of from 5,000 to 125,000, and at least one intermediate polymer block B of a con-jugated diene having an average molecular weight of from 10,000 to 300,000, in which the terminal polymer blocks A constitute from 8 to 55% by weight of the block copolymer and no more than 25% of the arene double bonds of the polymer blocks A and a~ least 80% of ~he aliphatic double bonds of the polymer blocks B ha~e been reduced by hydrogenation, which composition is characteri~ed in ~hat the composition comprises:
(a) 4 to 40 parts by weight of the partially hydrogenated block copolym0r;
~b) a polycarbonate having a mel~ing point oYer 120C;
~c) 5 to 48 parts by weight of at leas~ one dissimilar engineering thermo-plastic resin being selected from the group consisting of polyamides, polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones), acetal resins, thermoplastic polyure*hanes, halogenated thermoplastics, and nitrile resins, in which the weight ratio of the polycarbonate to the dissimilar engineering ~hermoplastic resin is greater than 1:1 so as to form a polyblend wherein at least two of the polymers form at least partial continuous interlocked networks with each other.
In anotheT aspect, the invention p~ovides a process ~or thepreparation of a composition as defined ~bove, charac~eri~ed in that ~0 (a~ 4 to 40 parts by weight of a partially hydrogenated block copolymer comp~ising at least two terminal polymer blocks A o a monoalkenyl arene having an average molecular weigh~ of from 5,000 to 125,000, and at leas~ one intermediate polymer block B of a conjugated diene having an average molecular weight o from 10,000 to 300,000, in which the terminal polymer blocks A constitute from 8 to 55% by weight o~ the block copolymer and no more than 25~ of the arene double bonds of the polymer blocks A and at leas~ 80% of the aliphatic double bonds of the polymer blocks B have b~en reduced by hyd~ogenation, are mixed at a processing temperature Tp of between 150C and 400C with 3a Cb) ~ polycaTbona~e having a melting point over 120C, and (c) 5 to 48 parts by weight of at least one dissimilar engineering thermo-plastic resin being selected ~rom the group consisting of polyamides~

3~

polyolefins, thel~oplastic polyesters, poly(aryl ethers), poly~aryl sul-phones~ acetal resins, thermoplastic polyuTethanes, halogenated thermo-plastics and nitrile resins, in ~hich the weight ratio of the polycarbonate to ~he dissimilar engineeTing thermoplastic resin is greater than 1:1 so as ~o orm a polyblend wherein at least two of the polymers form at least partial continuous interlock0d networks with each other.
The block copolymer of ~he invention effectively acts as a mechanical or structural stabilizer which interlocks , the various polymer structure networks and prevents the consequent separation of the polymers during processing and their subsequent use. As defined more fully herein-after, the resulting structure of the polyblend (short for "polymer blend") is that of at least two partial continuous interlocking networks. This interlocked structure results in a dimensionally stable polyblend that will not delaminate upon extrusion and subsequent use.
To produce stable blends it is necessary that at least two of the polymers have at least partial continuous networks which interlock with each other. Preferably, the block copolymer and at least one other polymer have partial continuous interlocking network structures. In an ideal situation all of the pol~mers would have complete con-tinuous networks which interlock with each other. A ~ -partial continuous network means that a portion of the polymer has a continuous network phase structure while the other portion has a disperse phase structure. Prefer-ably/ a major proportion (greater than 50% by weight) of the partial continuous network is continuous. As can be readily seen, a large variety of blend structures is possible since the structure of the polymer in the blend may be completely continuous, completely disperse, or partially continuous and partially disperse. ~urther yet, the disperse phase Or one polymer may be dispersed in a - 7 - ~ 37 second polymer and not in a third polymer. To illustrate some of the structures, the following lists the various combinations of polymer structures possible where all structures are complete as opposed to partial structures.
Three polymers (A, B and C) are involved. The subscript "c" signifies a continuous structure while the subscript "d7' signifies a disperse structure. Thus, the designation ''ACB'' means that polymer A is continuous with polymer B, and the designation "BdC'~ means that polymer B is disperse in polymer C, etc.
AcB AcC BCC
AdB AcC BcC
AcB AcC BdC
BdA AcC BcC
BdC AcB ACC
CdA AcB ACC
CdB AcB ACC
Through practice of the invention, it is possible to -7a-improve one type of physical property of the composite blend while not causing a significant deterioration in another physical property. In the past this has not always been possible. For example, in the past it was expected that by adding an amorphous rubber such as an ethylene-propylene rubber to a thermoplastic polymer to improve impact strength, one would necessarily obtain a composite blend having a significantly reduced heat distortion temperature (HDT). This results from the fact that the amorphous rubber forms discrete particles in the composite and the rubber, almost by definition, has an exceedingly low HDT, around room temperature. How-ever, in the present invention it is possible to significantly improve impact strength while not de-tracting from the distortion temperature. Even more surprising, as shown in the illus-trative Examples that follow, in some cases the heat distortion temperature surprisingly increases as the amount of the subject block copolymers is increased, which phenomer.onis totally un-expected from what one skilled in the art would expect.
This ability to tailor-make polymer blends in order to arrive at a much improved balance of properties has not been taught in the pri~or art.

It is particularly surprising that even just small amounts of the block copolymer are sufficient to stabilize the structure of the polymer blend over very wide relative concentrations. For example, as little as four parts by weight of the block copolymer is sufficient to stabilize a blend of 5 to 90 parts by weight polycarbonate with 90 to 5 parts by wei~ht of a dissimilar engineering thermoplastic.
In addition, it is also surprising that the block co-polymers are userul in stabilizing polymers of such a wide ; ~-variety and chemical make-up. As explained more fully hereinafter, the block copolymers have this ability to `~
stabilize a wide variety of polymer over a wide range of concentrations since they are oxidatively stable, possess essentially an infinite viscosity at zero shear stress~
and retain network or domain structure in the melt.
Another significant aspect of the invention is that the ease of processing and forming the various polyblends is greatly improved by employing the block copolymers as stabilizers. ~ `
The block copolymers employed in the composition according to the invention may have a variety of geometrical ~ `
structure, since the invention does not depend on any specific geometrlcal structure, but rather upon the chemical constitution of each of the polymer blocks. Thus, the block copolymers may be linear, radial or branched.
Methods for the preparation of such polymers are known in the art. The structure of ~he polymers is determined by their methods of polymerization. For example, linear polymers result by sequentia:L introduction of the desired monomers into the reaction vessel when using such initiators as lithium-alkyls or dilithio-stilbenea or by coupling a two-segment block copolymer with a difunctional coupling agent. Branched structures,on the other hand, may be obtained by the use of suitable coupling agents having a functionality with respect to the precursor polymers of three or more. Coupling may be effected with multifunctional coupling agents, such as dihaloalkanes or -alkenes and divinyl benzene as well as certain polar compounds, such as silicon halides, siloxanes or esters of monohydric alcohols with carboxylic acids.
The presence of any coupling residues in the polymer may -be ignored for an adequate description of the polymers forming a part of the compositions of this invention.
Likewise, in the generic sense, the specific structures also may-be ignored. The invention applies especi~lly to the use of selectively hydrogenated polymers having the configuration before hydrogenation Or the following typical species:
polystyrene-polybutadiene-polystyrene (SBS) polystyrene-polyisoprene-polystyrene (SIS) poly(alpha-methylstyrene)polybutadiene-poly(alpha-methylstyrene) and poly(alpha-methylstyrene)polyisoprene-poly(alpha-methylstyrene). ~ , Both polymer blocks A and B may be either homopolymer or random copolymer blocks as long as each polyMer block predominates in at least one class Or the monomers charac~
terizing the polymer blocks. The polymer block A may ' comprise homopolymers of a monoalkenyl arene and co-polymers of a monoalkenyl arene with a conjugated diene as long as the polymer blocks A individually predominate ,~ -in monoalkenyl arene units. The term "monoalkenyl arene"
will be taken to include especially styrene and its ' analogues and homologues including alpha-methylstyrene and ring-substituted styrenes, particularly ring-rnethyl~
ated styrenes. The preferred monoalkenyl arenes are styrene and alpha-methylstyrene, and styrene is particularly preferred. The polymer blocks B may comprise '~
homopolymer~ of a conjugated diene, such as butadiene or isoprene J and copolymers of a conjugated diene with a monoalkenyl arene as long as the polymer blocks B pre- -dominate in conjugated diene units. When the monomer employed is butadiene, it is preferred that between 35 and 55 mol. per cent of the condensed butadiene units in the butadiene polymer block have 1,2-configuration. Thus, when such a block is hydrogenated, the resulting product is, or resembles, a regular copolymer block of ethylene and butene-1 (EB). If the conjugated diene employed is ~ - ~ ~

isoprene, the resulting hydrogenated product is or resembles a regular copolymer block of ethylene and propylene (EP).
Hydrogenation of the precursor block copolymers is preferably effected by use of a catalyst comprising the reaction products of an aluminium alkYl compound with nickel or cobalt carboxylates or alkoxides under such conditions as to substantially completely hydrogenate at least ~0% of the aliphatic double bonds, while hydrogenating no more than 25% of the alkenyl arene aromatic double bonds. Preferred block copolyrners are - -those where at least 99% of the aliphatic double bonds are hydrogenated while less than 5% of the aromatic double bonds are hydrogenated.
The average molecular weights of the individual blocks may vary within certain limits. The block co-polyrner present in the composit:ion according to the invention has at least two terminal polymer blocks A of a monoalkenyl arene having a number average molecular weight of from 5,000 to 125,000g preferably from 7,000 to 60,000, and at least one intermediate polyrner block B
of a conjugated diene having a nurnber average molecular ~;
weight of from 10,000 to 300,000, preferably from 30,000 to 150~000. These molecular weights are most accurately determined by tritium counting methods or osmotic pressure measurements. -The proportion of the polymer blocks A of the mono-alkenyl arene should be between 8 and 55% by weight of the block copolymer, preferab]y between 10 and 30% by ;
weight.
The polycarbonates present in the compositions ac-cording to the invention are of the general formulae~

O
(Ar - A Ar - O C - )n- I : :

and ~Ar- -O C ~n II ~
~' :-wherein Ar represents a phenylene or an alkyl, alkoxy,halogen or nitr~ubstituted phenylene group; A represents a carbon-to-carbon bond or an alkylidene, cycloalkylidene, ~ -alkylene, cycloalkylene, a~o, imino, sulphur, oxygen, sulphoxide or sulphone group, and n is at least two.
...

The preparation oI` the polycarbonates is well known.
A preferred method of preparation is based on the reaction carried out by dissolving the dihydroxy component in a base, such as pyr;dine and bubbling phosgene into the stirred solution at the desired rate. Tertiary amines may be used to catal~ze the reaction as well as to act as acid `~
acceptors throughout the reaction. Since the reaction is normally exothermic, the rate of phosgene addition can be used to control the reaction temperature. The reactions generally utilize equimolar amounts Or phosgene and (li-hydroxy reactants, however, the molar ratios can be v~ricd dependent upon the reaction conditions.
In the formulae I and II mentioned, Ar and l~ are, preferablyg p-phenylene and isopropylidene, respectively.
This polycarbonate is prepared by reacting para,para'iso~
propylidenediphenol with phosgene and is sold under the trade mark LEXAN ~ and under the trade mark ME~LON ~
This commercial polycarbonate has a molecular weight Or ~ .
around 18,000, and a melt temperature of over 230C.
Other polycarbonates may be prepared by reacting other dihydroxy compounds, or mixtures of dihydroxy compounds, with phosgene. The dihydroxy compounds may include aliphatic dihydroxy compounds although for best high temperature properties aromatic rings are essential. The dihydroxy compounds may include within the structure diurethane ;
linkages. Also, part o~ the structure may be replaced by siloxane linkage.

~T~ 2~B7 The term "dissimilar engineerir-g thermoplastic resin"
ref'ers to engineering l;herrnoplastic resins different from those encompassed by the polycarbonates present in the compositions according to the invention.
The term "engineering thermoplastic resin" encompasses the various polymers found in the classes listed in Table A
below and thereaf`ter defined in the specification.
TABLE _ 1. Polyolefins

2. Thermoplastic polyesters

3. Poly(aryl ethers) and poly(aryl sulphones)

4. Polyamides

5. Qcetal resins

6. Thermoplastic polyurethanes

7- Halogenated thermoplastics

8. Nitrile resins Preferably these engineering thermoplastic resins have glass transition temperaturesor apparent crystalline melting points (defined as that temperature at which the modulus, at low stress, shows a catastrophic drop) of over 120C, preferably betT~een 150C and 350C, and are capable of ~orming a continuous network structure through a thermally reverslble cross-linking mechanism.
Such thermally reversible cross-linking mechanisms in-clude crystallites, polar aggregations, ionic aggregations, lamellae, or hydrogen bonding. In a specific embodiment, - 1 5- ~ 237 where the viscosity ofthe block copolymer or blended block copolymer composition at processing temperature Tp and a shear rate of 100 s 1 is n, the ratio of the viscosity of the engineering thermoplastic resins, or blend of engineering thermoplastic resin with viscosity modifiers to n may be between 0.2 and 4.0, preferably 0.8 and 1.2. As used in the specification and claims, the viscosity of the block copolymer, polycarbonate and the thermoplastic engineering resin is the "melt viscosity"
obtained by employing a piston-driven capillary melt rheometer at constant shear rate and at some consistent temperature above melting, say 260C. The upper limit (350C) on apparent crystalline melting point or glass transition temperature is set so that the resin may be processed in low to medium shear rate equipment at com-mercial temperature levels of 350C or less. ;
The engineering thermoplastic resin includes also blends of various engineering thermoplastic resins and blends with additional viscosity modifying resins.
~hese various classes of engineering thermoplastics are defined below.
The polyolefins, if present in the composition ac- -cording to the invention are crystalline or crystallizable.
They may be homopolymers or copolymers and may be~derived from an alpha-olefin or 1-olefin having 2 to 5 carbon atoms. Examples of particular useful polyolefirsinclude ~ 3~

low-density polyethylene, high-density polyethylene~ iso-tactic polypropylene, poly(1-butene), poly(4-methyl-1-pentene), and copolymers of 4 methyl-1-pentene with linear or branched alpha-olefins. A crystalline or crystallizable structure is important in order for the polymer to be capable of forming a continuous structure with the other polymers in the po]ymer blend according to the invention. The nurnber average molecular weight of the polyolefinsmay be above 10,000, preferably above 50,000. In addition, the apparent crystalline melting point may be above iOOC, preferably between iOOC and 250C, and more preferably between 140C and 250C.
The preparation of these various polyolefins are well known. See generally "Olefin Polymers", Volume 14, Kirk-Othmer Encyclopedia of Chemical Technology, pages 217-335 (1967).
When a high-density polyethylene is employed, it has an approximate crystallinity of over 75% and a density in \

2~

kilograms per litre (kg/1) of between 0.94 and 1.0 while when a low density polyethylene is employed, it has an approximate crystallinity of over 35% and a density o~
between 0.90 kg/1 and 0.94 kg/1. The composition ac-cording to the invention may contain a polyethylene havinga number average molecular weight of 50,000 to 5007000.
When a polypropylene is employed, it is the so- -called isotactic polypropylene as opposed to atactic polypropylene. The number average molecular weight Or the polypropylcne employedmaYbeineXcess of 100,000. The poly-propylene rnay be prepared using methocls of the prior art. Depending on the specific catalyst and polymer- -ization conditions employed, the polymer produced may contain atactic as well as isotactic, syndiotactic or so-called stereo-block molecules. These may be separated by selective solvent extraction to yield products of low atactic content that crystalli~e more completely.
The preferred commercial polypropylenes are generally prepared uslng a solid, crystalline, hydrocarbon-in-soluble catalyst made from a titanium trichloride com~position and an aluminium alkyl compound, e.g., tri-ethyl aluminium or diethyl aluminium chloride. If desired, the polypropylene employed is a copolymer containing minor (1 to 20 per cent by weight) amounts of ethylene or another alpha-ole~in as comonomer.

2~7 ., , The poly(1-butene) preferably has an isotactic structure.
The catalysts used in preparing the poly(1-butene) are preferably organo~metallic compounds commonly referred to as Ziegler-Natta catalysts. A typical cata]yst is the interacted product resulting from mixing equimolar quan-tities of titanium tetrachloride and triethylaluminium.
The manu~acturing process is normally carried out in an inert diluent such as hexane. Manufacturing operations, in all phases of po:Lymer formation, are conducted in such a manner as to guarantee rigorous exclusion Or water even in trace amounts.
One very suitable polyolefin is poly(4-methyl-1-pentene).
Poly(4-methyl-1-pentene) has an apparent crystalline melt-ing point of between 240 and 250 C and a relative density f between 0.80 and 0.85. Monomeric 4-methyl-1-pentene is commercially manufactured by the alkali-metal catalyzed dimerization of propylene. ~he homopolyrnerization o~
4-methyl-1-pentene with Ziegler-Natta catalysts is described in the Kirk~Othmer Enclopedia of ~hemical Technology, Supplement volume, pages 789-792 (second edition, 1971).
However, the isotactic homopolymer of 4-methyl-1-pentene has certain technical defec-ts, such as brittleness and inadequate transparency. Therefore, commercially available poly(4-methyl-1-pentene) is actually a copolymer with minor proportions of other alpha-olefins, together with the addition of suitable oxidation and melt stabilizer - - 1 9 - ~ ~7 systems. These copolymers are described in the Kirk-Othmer Encyclopedia of Chemical Technology, Supplement volume, pages 792-907 (second edition, 1971), and are ~ available under the trade ~me TPX ~ resin. Typical alpha-olefins are linear alpha-olefins having from 4 to 18 carbon atoms. Suitable resins are copolymers of 4-methyl-1-pentene with from 0.5 to 30% by weight of a linear alpha-olefin.
If desired, the polyolefin is a mixture of various polyolefins. However, the much preferred polyolefin is isotactic polypropylene.
The thermoplastic polyesters,if present in the com-positions according to the invention, have a generally crystalline structure, a melting point over 120C, and are thermoplastic as opposed to thermosetting.
\\ ;~

One particularly useful group of polyesters are those thermoplastic polyesters prepared by condensing a di-carboxylic acid or the lower alkyl ester, acid halide, or anhydride derivatives thereof with a glycol, according ~ 5 to methods well known in the art.
Among the aromatic and aliphatic dicarboxylic acids suitable for preparing polyesters are oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, iso-phthalic acid, p-carboxyphenoacetic acid, p,p'~isarboxydiphe-nyl, p,p'-dicarboxydiphenylsulphone, p-carboxyphenoxyacetic acid, p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyric acid, p-carboxyphenoxyvaleric acid, p-carboxyphenoxyhexanoic ac~d, p,p'-dicarboxydiphenylmethane, p,p-dicarboxydiphenylpropane, p,p'-dicarboxydiphenyloctane, 3-alkyl-4-(~-carboxyethoxy)-ben~oic acid, 2~6-naphthalene dicarboxylic acid, and 2~7-naphthalene dicarboxylic acid. Mixtures of dicarboxylic acids can also be employed. Terephthalic acid is particularly preferred.
The glycols suitable for preparing the polyesters include straight-chain al~ylene glycols of 2 to 12 carbon atoms, such as ethylene glycol, lg3-propylene glycol, 1,6-hexylene glycol, 1,10-decamethylene glycol, and 1,12-dodecamethylene glycol. Aromatic glycols can be substituted in whole or in part. Suitable aromatic dihydroxy compounds include p-xylylene ~lycol, pyrocatechol, resorcinol, %3~

hydroquinone, or alkyl-substituted derivatives of these compounds. Another suitable glycol is 1,4-cyclohexane dimethanol. Much preferred glycols are ~e straight-chain alkylene glycols having 2 to 4 carbon atoms.
A preferred group of polyesters are poly(ethylene terephthalate), poly(propylene terephthalate), and poly-(butylene terephthalate). A much preferred polyester is poly(butylene terephthalate). Poly(b~tylene terephthalate), a crystalline copolymer, may be rormed by the polycondensation of 1,4~butanediol and dimethyl terephthalate or terephthalic acid, and has the generalized formula:

C_o ~-~to-~

n where n varies from 70 to 140. The average molecular weight of the poly(butylene terephthalate) preferab]y varies from 20,000 t~ 25,000.
Commercially available poly(butylene terephthalate) is B~ available under the trade ~*m~ VALOX ~ thermoplastic polyester. Other commercial polymers include CELANEX
TENITE ~ and VITUF ~ .
Other useful polyesters include the cellulosic esters.
The thermoplastic cellulosic esters employed herein are widely used as moulding, coating and film-forming materials -2~

and are well known. These materials include the solid thermoplastic forms of cellulose nitrate, cellulose acetate (e.g., cellulose diacetate, cellulose tri-acetate), cellu1ose butyrate, cellulose acetate butyrate, cellulose propionate, cellulose tridecanoate, carboxy-methyl cellulose, ethyl cellulose, hydroxyethyl cellulose and acetylated hydro~yethyl cellulose as described on pages 25-28 of Modern Plastics Encyclopedia~ 19~1-72, and references listed there;n.
Another userul polyester is a polyp;valolactone. Poly-pivalolactone is a linear polymer having recurring ester structural units mainly Or the formula:

CH2 - C(C~3-)2 ~ C(0)0 i.e., units derived from pivalolactone. Preferably, the poly-ester is a pivalolactone homopolymer. Also included, however~are the copolymers Or pivalolactone wlth no rnore tharl 50 mol.~, preferably not more than ~0 mol.% of another beta-propio-lactone, such as beta-propiolactone, alpha,alpha-diethyl-beta-propiolactone and alpha-methyl-alpha-ethyl-beta-propio-lactone. The term "beta-propiolactones" re~ers to beta-propiolactone (2-oxetanone) and to derivatives thereof which carry no substituents at the beta-carbon atom of the lactone ring. Preferred beta-propiolactones are those containing a tertiary or quaternary carbon atom in the alpha-position relative to the carbonyl group. Especially preferred are the alpha,alpha-dialkyl-beta-propiolactones wherein each Or the alkyl groups independently has from one to four carbon atoms.

32~

-23~

Examples Or useful monomers are:
alpha-ethyl-alpha-methyl-beta-propiolactone, alpha-methyl-alpha-isopropyl-beta-propiolactone, alpha-ethyl-alpha-n-butyl-beta-propiolactone, alpha-chloromethyl-alpha-methyl-beta-prop:iolactone, alpha~alpha-bis(chloromethyl~-beta-propiolactone, and alpha,alpha-dimethyl-beta-propiolactone (pivalolactone). ~ ;
These polypivalolactones have an average molecular weight in excess of 20,000 and a melting point in excess of 120C.
Another useful polyester is a polycaprolactone.
Preferred poly(~-caprolactones) are substantially linear polymers in which the repeating unit is:
rO_ ol ~:
t c~l2 c~l2 cll2_cH2 CH2 c~

These polymers have similar properties to the polypivalo-lactones and may be prepared by a similar polymerization mechanism.
Various polyaryl polyethers are also useful as engineer-ing thermoplastic resins. The poly(aryl polyethers) which may be present in the composition according to the invention include the linear thermoplastic polymers composed Or re-curring units having the formula:

(0 G 0 - G' ~ - I
wherein Gisthe residuum of a dihydric phenol selected from the group consisting Or:

~ 3_ II
, and ~; ~ R ~

wherein R represents a bond between aromati.c carbon atoms, __ O ~ S - , S- s-,or -l divalent hydrocarbon radica].
having from 1 to 18 carbon atoms i,nclusive, and G' i.s the residuum Or a dibromo or di-i.odobenzenoid compound selected f'rom the group consistin~ Or:

~ IV

and - ~ ~ R \73 v wherein R' represents a bond between aromatic carbon atoms, -O , - S g - S S - ,or a divalent hydrocarbon rad~cal having ~rom 1 to 18 carbon atoms inclusive, with the provisions that when R is O - -, R' is other than O ; when R' is O , R is other than -O - ;
when G is II, G' is V, and when G' is IV, G is III.

Polyarylene polyethers Or this type exhibit excellent physical properties as well as excellent thermal oxidative and chemical stability. Commercial poly(aryl polyethers) are available under the trade ~e ARYLON T ~ Polyaryl ethers, having a melt temperature of between 280C and 310C.
Another group Or useful engineering thermoplastic resins include aromatic poly(sulphones) comprising re-peating units of the formula: -.
- -Ar S02 - ~
in which Ar i.s a bivalent aroma~ic radical and may vary ~ ~ , from unit to unit in the polymer chain (so as to f`orm co-polymers of various kinds). Thermoplastic poly(sulphones) ~enerally have at least some units of the structure:
,~3-z~

SO2 `

in which Z is oxygen or sulphur or the residue of an aromatic diOlg such as a 4,~'-bisphenol. One example of such a poly(sulphone) has repeating units Or the formula:

~ O ~--S02~

another has repeating units of the formula:

~_s~ so2--and others have repeating units of the formula:
~ S02 ~ _ O ~C~/3~o or copolymerized units in various proportions of the formula: ~-and ~_o~3-so2- ~ ~ ~

The thermoplastic poly(sulphones) may also have repeatlng ~: :
units having the formula: ~

_~_o~3-S2-- ~

Poly(ether sulphones) having repeating units of the following structure:

t~ ~ s02~

and poly(ether sulpholles) having repeating units of the following structure:

52 ~ ' ~ C ~ ~n are also useful as engineering thermoplastic resins.
By polyamide is meant a condensation product which contains recurring aromatic and/or aliphatic amide groups ~
as integral parts of the main polymer chain, such products ~ ;
being known generically as "nylons". A polyamide may be obtained by polymerizing a mono-aminomonocarboxylic acid or an internal lactam thereof having at least two carbon atoms between the amino and carboxylic acid groups; or by polymerizing substantially equimolar proportions of a diamine which contains at least two carbon atoms between ~ ~
the amino groups and a dicarboxylic acid; or by polymer- ;
i~ing a mono-aminocarboxylic acid or an internal lactam thereof as defined above together with substantially equi-molar proportions of a diamine and a dicarboxylic acid.
The dicarboxylic acid may be used in the form of a functional ~-derivative thereof, for example an ester.

-28~ 8 ~ 3~

The term "substantially equimolecular proportions"
(of the diamine and of the dicarboxylic acid) is used to co~er both strict equimolecular proportions and the slight departures therefrom which are involved in conventional 8~23~

techniques for stabilizing the viscosity of the resultant polyamides.
As examples of the sa:id mono-aminomonocarboxylic acids or lactams thereof there may be mentloned those compounds containing from 2 ~o 16 carbon atoms be-tween the amino an~
carboxylic acid groups, said carbon atoms forming a ring with the - -CO.N~I group in the case of a lactam. As particular examples of aminocarboxylic acids and lactams there may be mentioned ~-aminocaproic acid, butyrolactam, pivalolactam, caprolactam, capryl-lactam, enantholactam, undecanolactam, dodecanolactam and 3- and 4-amino benzoic acids.
Examples of the said diamines are diamines of the general formula H2N(CH2)nNH2, wherein n is an integer of from 2 to 16, such as trimethylenediamine~ tetramethylene- ~ -diamine, pentamethylenediamine, octamethylenediamine, decamethylenediamineg dodecamethylenediamine, hexadeca- ;
methylenediamine, and especially hexamethylenediamine.
C-alkylated diamines, e.g.s 2,2-dimethylpentamethylene-diamine and 2,2,4-and 2,4,4-trimethylhexamethylenediamine are further examples. Other diamines which may be mentioned as examples are aromatic diamines, e.g., p-phenylene~
diami.ne, 4,4'-diaminodiphenyl sulphone~ 4,4'-diaminodi-phenyl ether and 4,LI t -diaminodiphenyl sulphone, 4,4'-di-aminodiphenyl ether and 4~4'-diaminodipilenylmethane; and cycloaliphatic diamines, for example diaminodicyclohexyl-methane.

~ 37 The said dicarboxylic acids may be aromatic, ror example isophthali.c and terephthalic acids. Preferred dicarboxylic acids are of the formula l-IOOC.Y.COOH, wherein Y represents a divalent aliphatic radical containing at least 2 carbon atoms, and examples of such acids are sebacic acid, octadecanedioicacid, suberic acid, azelaic aci.d, undecanedioic acid, ~lutaric acid, pimelic acid, and especially adipic acid. Oxalic acid is also a prererred acid.
Speci~ically the following polyamides may be in-corporated in the thermoplastic polymer blends of the invention:
polyhexamethylene adipamide (nylon 6:6) polypyrrolidone (nylon 4) polycaprolactam (nylon 6) polyheptolactam (nylon 7) polycapryllactam (nylon 8) polynonanolactam (nylon 9) poly~ndecanolactam (nyIon 11) polydodecanolactam (nylon 12) polyhexamethylene azelaiamide (nylon 6:9) polyhexamethylene sebacamide (nylon 6:10) polyhexamethylene isophthalamide (nylon 6:iP) polymetaxyly].ene~ipamide (nylon MXD:6) polyamide o~ hexamethylene diarnine and n~dodecanedioic acid (nylon 6:12) ~ ~ ~9~3~37 polyamide of dodecamethylenediamine and n-dodecanedioic acid (nylon 12:12).
Nylon copolymers may also be used, for example co-polymers of the following:
hexamethylene adipamide/caprolactam (nylon 6:6/6) hexamethylene adipamide/hexamethylene-isophthalamide (nylon 6:6/6ip) hexamethylene adipamide/hexamethylene-terephthalamide (nylon 6:6/6T) trimethylhexamethylene oxamide/hexamethylene oxamide ~
(nylon trimethyl-6:2/6:2) ~ ~.
hexamethylene adipamide/hexamethylene-azelaiamide ~
(nylon 6:6~6:9) ~ :
hexamethylene adipamide/hexamethylene-azelaiamide/ ~ -~
caprolactam (nylon 6:6/6:9/6).
Also useful is nylon 6:3. This polyamide is the product :~
of the dimethyl ester of terephthalic acid and a mixture of isomeric trimethyl hexamethylenediamine.
Preferred nylons include nylon 6,6/6, 11, 12, 6/3 and 6/12.
The number average molecular weights of the polyamldes may be above 10,000.

3~

The acetal resins which may be present in the com-positions according to the invention include the high molecular weight E)olyacetal homopolymers made by polymer-izing formaldehyde or trioxane. These polyacetal homo-~,y .
polymers are commercia]1y available under the trade ~_ DELRIN ~. A related polyether-type resin is available under the trade ~ PENTON~_J and has the structure:
_.
C~12Cl ' ' :
_ _o - C~l2 - ~ Cl~2- _ C'~l2Cl n The acetal resin prepared from rormaldehyde has a high molecular weight and a structure typified by the following:

- H- O ( CH2- O- CH2-0) H

where terminal groups are derived from controlled amounts of water and the x de\lotes a large (preferably 1500) number of formaldehyde units linked in head-to~tail fashion. To in-crease thermal a~d chemical resistance, terminal groups are typically converted to esters or ethers.
Also included in the term polyacetal resins are the polyacetal copolymers. These copolymers lnclude block co-polymers of formaldehyde with monomers or prepolymers other materials capable of providing active hydrogens, ~ 7 -33- ~`

such as alkylene glycols, polythiols, vinyl acetate-acrylic acid copolymers, or reduced butadiene/acrylonitrile polymers.
Celanese has commercially available a copolymer Or formaldehyde and ethylene oxide under the trade ~ CELCON
that is userul in the blends of the present invention. These copolymers typically have a structure comprising recurrin~ -units having the formula: ~ ~
, ~ "
. _ ~ H I ~

wherein each R1 and R2 is selected from the group consisting Of hydrogen, lower alkyl and lower halogen substituted alkyl radicals and wherein n is an integer from zero to three and wherein n is zero in from ~5% to 99.9% of the recurring units.
Formaldehyde and trioxane can be copolymerized with other aldehydes, cyclic ethers, vinyl compounds, ketenes, cyclic carbonates, epoxides~ isocyanates and ethers. T~hese compounds include ethylene oxide, 1,3-dioxolane, 1,3-dioxane, 1,3-dioxepene, epichlorohydrin, propylene oxide, isobutylene oxide, and styrene oxide.

-3L~ 7 Polyurethanes, otherwise known as isocyanate resins, also can be employed as engineering thermoplastic resin as long as they are thermoplastic as opposed to thermosetting.
For example, polyurethanes formed from toluene di-iso-cyanate (TDI) or diphenyl methane 4,4-di-isocyanate (MDI) and a wide range of polyolsg such as polyoxyethylene glycol, polyoxypropylene glycol, hydroxy-terminated polyesters, poly-oxyethylene-oxypropylene glycols are suitable.
These thermoplastic polyurethanes are available under the trade ~ Q-THANE ~ and under the trade ~ffle PE~LETHANE
CPR.
Another group of useful engineering thermoplastics in-clude those halogenated thermoplastics having an essentially crystalline structure and a melt point in excess of 120C.
These halogenated thermoplastics include homopolymers and copolymers derived from tetrafluoroethylene, chlorotrifluoro-ethylene, bromotrifluoroethylene, vinylidene fluoride, and vinylidene chloride.
Polytetrafluoroethylene (PTFE) is the name given to fully fluorinated polymers o~ the basic chemical formula (CF2 CF2)n which contain 76% by weight fluorine.
Ibe~ h,~l / crystalline and have a crystall ine melting point of` over 300 C. Commercial PTI~E is available L~ under the trade-r~e TEFLON~ and under the trade-~*~-FLUON ~ . Polychlorotrifluoroethylene (PCTL~IE) ancl poly-bromotrifluoroethylene (PBTFE) are also available in high molecular weights and can be employed in the present in-vention.
Especially preferred halogenated polymers are homo-polymers and copolymers Or vinylidene fluoride. Poly-(vinylidene fluoride) homopolymers are the partially fluorinated polymers of the chemical formula -~-CH2 - C~2 ~ .
These polymers are tough linear polymers with a crystalline melting point at 170 C. Commercial homopolymer is available under the trade ~e KYNAR ~ The term "poly(vinylidene fluoride)" as used herein refers not only to the normally solid homopolymers of vlnylidene fluoride, but also to the normally solid copolymers of vinylidene fluoride containing at least 50 mol.% of polymerized vinylidene fluoride units, preferably at least 70 mol.% vinylidene fluoride and more preferably at least 90 mol.%. Suitable comonomers are halogenated olefins containing up to 4 carbon atoms, for example5 sym. dichlorodifluoroethylene, vinyl fluoride, vinyl chloride, vinylidene chloride, perfluoropropene,per-fluorobutadiene, chlorotrifluoroethylene, trichloroethylene and tetrafluoroethylene.
Another useful group of halogenated thermoplastics include homopolymers and copolymers derived from vinylidene chloride. Crystalline vinylidene chloride copolyrners are ~36-especially preferred. The normally crystaJline vinylidene chloride copolymers that are useful in the present in-vention are those containing at least 70% by weight Or vinylidene chloride together with 30% or less of a co-polymerizable monoethylenic monomer. Exemplary Or suchmonomers are vinyl chloride, vinyl acetate, vinyl propionate, acrylonitrile, alkyl and aralkyl acrylates havir.g alkyl and aralkyl groups of up to about ~ carbon ;~
atoms~ acrylic acid~ acrylamide, vinyl alkyl ethers, vinyl alkyl ketones, acrolein, allyl ethers and others, butadiene and chloropropene. Know~l terndry composit~on also may be employed advantageously. Represcntative of such polymers are those composed of at least 70% by weight of vinylidene chloride with the remainder madé up of, for example, acrolein and vinyl chloride, acrylic acid and ;
acrylonitrile, alkyl acrylates and alkyl methacrylates, acrylonitrile and butadiene, acrylonitrile and itaconic acid, acrylonitrile and vinyl acetate~ vinyl propionate or vinyl chloride, allyl esters or ethers and vinyl chloride, butadiene and vinyl acetate, vinyl propionate, or vinyl chlor`ide and vinyl ethers and vinyl chloride.
Quaternary polymers of similar monomeric composition will also be known. Particularly useful for the purposes the present invention are copolymers of from 70 to 95% by weight vinylidene chloride with the balance being vinyl chloride. Such copolymers may contain conventional amounts and types of plasticizers, stabilizers, nucleators and extrusion aids. ~urther, blends of two or more of such normally crystalline vinylidene chloride po]ymers may be used as well as blencls comprising such normally crys-talline polymers in combination with other polymeric modifiers, e.g., the copolymers of ethylene-vinyl acetate, styrene-maleic anhydride, styrene-acrylonitrile and poly-ethylene.
The nitrile resins useful as engineering thermoplastic resin are those thermoplastic materials having an alpha,b~ta-olefinically unsaturated mononitrile content of 50% by weight or greater. These nitrile resins may be homopolymers, copolymers, grafts of copolymers onto a rubbery substrate, or blends of homopolymers and/or copolymers.
The alpha,beta-olefinically unsaturated mononitriles encompassed herein have the structure Cl~2 C CN
R
where R is hydrogen, an alkyl group having from 1 to 4 carbon atoms, or a halogen. Such compounds include acrylo-nitrile, alpha-bromoacrylonitrile, alpha-fluoroacrylo-nitrile, methacrylonitrile and ethacrylonitrile. The mostpreferred olefinically unsaturated nitriles are acrylo-nitrile and methacrylonitrile and mixtures thereof.
These nitrile resins may be divided into several classes on the basis of complexity. The simplest molecular ~ 3 7 -3~-structure is a random copolymer, predominantly acrylonitrile or methacrylonitrile. The most common example is a styrene-acrylonitrile copolymer. Block copolymers of acrylonitrile, in which long segments of polyacrylonitrile alternate with segments of polystyrene, or of polymethyl methacrylate, are also known.
Simultaneous polymerization of more than two co-monomers produces an interpolymer, or in the case of three components, a terpolymer. A large number of co-monomers are known. These include alpha-olefins of ~rom 2 to 8 carbon atoms, e.g., ethylene, propylene, iso-butylene, butene-13 pentene-1, and their halogen and aliphatic substituted derivatives as represented by vinyl chloride and vinylidene chloride; monovinylidene aromatic hydrocarbon monomers o~ the general ~ormula: ;

C - -C

wherein R1 is hydrogen, chlorine or methyl and R2 is an aromakic radical of 6 to 10 carbon atoms which may also contain substituentsg such as halogen and alkyl groups attached to the aromatic nucleus, e.~., styrene~ alpha-methyl styrene, vinyl toluene, alpha-chlorostyrene, ortho-chlorostyrene, para-chlorostyrene, meta-chlorostyrene, ortho-methyl styrene, para-methyl styren~e, ethyl styrene, 2~7 isopropyl styrene, dichlorostyrene and vinyl naphthalene.

Especially preferred comonomers are isobutylene and styrene.

Another group of comonomers are vinyl ester monomers of the general formula:

H
R-~C=C
C=O ;~

wherein R3 i~ selected from the group comprising hydrogen, alkyl groups of rrom 1 to 10 carbon atoms, aryl groups of from 6 to 10 carbon atoms including the carbon atoms in ~-ring-substituted alkyl substituents; e.g., vinyl formate~
vinyl acetate, vinyl propionate and v:inyl benzoate.
Similar to the foregoing and also useful are the vinyl ether monomers of the general formula.
H2C=C H--O--RLl wherein R4 is an alkyl group of from 1 to 8 carbon atoms, an aryl group of from 6 to 10 carbons~ or a monovalent aliphatic radical of from 2 to 10 carbon atoms, which aliphatic radical may be hydrocarbon or oxygen-containing, e.g., an aliphatic radical with ether linkages, and may also contain other substituents, such as halogen and carbonyl. Rxamples of these monomeric vinyl ethers include vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl 2-chloroethyl ether, vinyl phenyl ether, vinyl iso-3~ ~

--l~o--butyl ether, vinyl cyclohexyl ether, p-butyl cyclohexyl ether, vinyl ekher or p-chlorophenyl glycol.
Other comonomers are those comonomers which contain a mono- or dinitr;le function. Examples of these include methylene glutaronitrile, (2,LI-dicyanobutene-1), vinyl-idene cyanide, crotonitrile, fumarodinitrile, maleodi- ~;
nitrile.
Other comonomers include the esters of olefinically unsaturated carboxylic acids,preferably the lower alkyl ~ -~
esters of alpha,beta-olefinically unsaturated carboxylic acids and more preferred the esters having the structure~

GH2 C---COOR2 ':' '~

wherein R1 is hydrogen, an alkyl group having from 1 to Ll:
carbon atorns, or a halogen and R2 is an alkyl group having from 1 to 2 carbon atoms. Compounds of this type include methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and methyl alpha-chloro acrylate. Most preferred are methyl acrylate, ethyl acrylate, methyl metha-crylate and ethyl methacrylate.
Another class of nitrile resins are the graft co~
polymers which ha~e a polymeric backbone on which branches of another polymeric chain are attached or grafted.
Generally the backbone is preformed in a separate reaction. ;
Polyacrylonitrile may be grafted with chains of styrene, ~ 7 vinyl acetate, or methyl methacrylate, for example. The backbone may consist of one, two, three~ or more com-ponents, and the grafted branches may be composed of one, two, three or more comonomers.
The most promising products are the nitrile co-polymers that are partially grafted on a preformed rubbery substrate. This substrate contemplates the use of a synthetic or natural rubber component such as poly-butadiene, isoprene, neoprene, nitrile rubbers, natural rubbers, acrylonitrile-butadiene copolymers, ethylene-propylene copolymers, and chlorinated rubbers which are used to strengthen or toughen the polymer. This rubbery component may be incorporated into the nitrile containing polymer by any of the methods ~hich are well known to those skilled in the art, e.g.~ direct polymerization of monomers, grafting the acrylonitrile monomer mixture onto the rubber backbone or physical admixtures of the rubbery component. Especially preferred are polymer blends derived by mixing a graft copolymer of the acrylonitrile and co-monomer on the rubber backbone with another copolymel of acrylonitrile and the same comonomer. The acrylonitrile based thermoplastics are frequently polymer blends of a grafted polymer and an ungrafted homopolymer.
Commercial examples of nitrile resins include B~EX
210 resin, an acrylonitrile-based high nitrile resin con-taining over 65% nitrile, and LOPAC ~ resin containing L2_ over 70% nitrile, three-fourths of it derived from metha-crylonitrile.
In order to better rnatch the viscosity ch~racteristics of the thermoplastic engineering resin, the polycarbonate and the block copolymer, it is sometimes useful to first blend the dissimilar thermoplastic engineering resin with a viscosity modifier before blending the resulting mixture with the ~lyccr~on~e and block copolymer. Suitable viscosity modifiers have a relatively high viscosity, a melt temper-ature of over 230 C, and possess a viscosity that is notvery sensitive to changes in temperature. Examples Or suit-able viscosity modifiers include poly(2,6-dimethyl-1,4-phenylene~oxide and blends Or poly(2,6-dimethyl-1,4-phenyl-ene)oxide with polystyrene.
~he poly(phenylene oxides) included as possible viscosity modifiers may be presenked by the following formula:
- ~
L
~o I , _ R'l m wherein ~1 is a monovalent substituent selected from the group consisting Or hydrogen, hydrocarbon radicals free Or a tertiary alpha-carbon atom, halohydrocarbon radicals having at least two carbon atoms between the halogen atom and phenol nucleus and being ~ree Or a tertiary alpha-carbon atom, hydrocarbonoxy radicals free of aliphatic, tertiary alpha-carbon atoms, and halohydro-carbonoxy radicals having at least two carbon atomsbetween the halogen atom and phenol nucleus and being free of an aliphatic, tertiary alpha-carbon atom; R'l is the same as Rl and may additionally be a halogen; m is an integer equal to at least 50, e.g., rrom 50 to ~00 and preferably 150 to 300. Included among these preferred polymers are polymers having a molecular weight in the range of between 6,ooo and 100,000, preferably 40,000.
Preferably, the poly(phenylene oxide) is poly(2,6-di-rnethyl-1,4-phenylene)oxi.de.
Commercially, the poly(phenylene oxide) is available as a blend with styrene resin. These blends typically comprise between 25 and 50% by weight polystyrene units, and are available ~nder the ~
trade ~ NORYL ~ thermop~astic resin~ The prererred molecular welght when employing a poly~phenylene oxide)/
polystyrene blend is between 10,000 and 50~000, preferably around 30,000.
The amount Or viscosity modifier employed depends primarily upon the di~erence between the viscosities o~
khe block copolymer and the engineering thermoplastic resin at the temperature Tp. The amounts may range from O to 100 parts by weight viscosity modifier per 100 parts by weight ~ -engineering thermoplastic resin3 preferably from 10 to 50 parts by weight per 100 parts of engineering thermoplastic resin.
There are at least two methods (other than the absence of delamination~ by which the presence of an interlocking network can be shown. In one method3 an interlocking net~
work is shown when moulded or extruded objects made from the blends of this invention are placed in a refluxing solvent that quantitatively dissolves away the block co-polymer and other soluble components3 and the remaining polymer structure (comprising the thermoplastic engineer-ing resin and ~lycarbonate)still has the shape and con-tinuity of the moulded or extruded object and is intact structurally without any crumbling or delamination, and the refluxing solvent carries no insoluble particulate matter. If these criteria are fulfil]ed, then both the unextracted and extracted phasescre interlocking and continuous. The unextracted phase must be continuous - `
because it is geometrically and mechanically intact.
The extracted phase must have been continuous before extraction, since quantitative extraction of a dispersed phase from an insoluble matrix is highly unlikely.
~inallyg interlocking networks must be present in order to have simultaneous continuous phases. Also, confirmation of the continuity of the unextracted phase may be -ll5~

conrirmed by microscopic examination. In the present blends containing more than two components, the interlocking nature and continuity of each separate phase may be established by selective extraction.
In the second method, a mechanical property such as tensile modulus is measured and compared with that expected from an assumed system where each continuous iso-tropically distributed phase contributes a fraction of the mechanical response, proportional to its compositional fraction by volume. Correspondence of the two values indicates presence of the interlocking network, whereas, if the interlocking network is not present, the measured value is different than that of the predicted value.
An important aspect of the present invention is that the relative proportions of the various polymers in the blend can be varied over a wide range. The relative proportions of the polymers are presented below in parts by weight (the total blend comprising 100 parts):
Parts by Preferred weight parts by _ight Dissimilar engineering thermoplastic resin 5 to 48 10 to 35 Block copolymer 4 to 40 8 to 20 ~ -46- ~ 3~

The polycarbonate is present in an amount greater than the amount of the dissimilar engineering thermo-plastic, i.e., the weight ratio of polycarbonate to dissimilar engineering therrnoplastic is greater than 1:1. Accordingly, the amount of polycarbonate may vary from 30 parts by weight to 91 parts by weight, prefer- -ably from 48 to 70 parts by weight. Note that the rninimum amount of block copolymer necessary to achieve these blends may vary with the particular engineering thermo-plastic.
The dissimilar engineering thermoplastic resin, polycarbonate and the block copolymer may be blended in any manner that produces the interlocking network. For example, the resin, polycarbonate and block copolymer may be dissolved in a solvent common for all and coagulated by admixing in a solvent in which none of the polymers are -soluble. But, a particularly usef`ul procedure is to intimately mix the polymers in the form of granules and~or powder in a high shear mixer. "Intimately mixing" means to mix the polymers with sufficient rnechanical shear and ~e~r~l ~o-rV to ensure that interlocking of the various :

~ 2~ 7 _1~7_ networks is achieved. Intimate mixing is typically achieved by employing high shear extrusion compounding machines, such as twin screw compounding extruders and thermoplastic extruders having at least a 20:l L/D ratio and a compression ratio of 3 or 4:l.
The mixing or processing temperature (Tp) is selected in accordance with the particular polymers to be blended.
For example, when melt blending the polymers instead of solution blending, it will be necessary to select a processing temperature above the melting point of the highest melting point polymer. In addi.tion, as explained more fully hereina~ter, the processing temperature may also be chosen so as to permit the isoviscous mixing of the polymers. The mixing or processin~ temperature may be between 150C and Ll00C, preferably between 230C and 300C.
Another parameter that is important in melt blendin~
to ensure the formation of interlocking networks is matching the viscosities of the block copolymer,~lY~rbnateand the dissimllar engineering thermoplastic resin (isoviscous mixing) at the temperature and shear stress of the mixing process. The better the interdispersion of the engineering resin and ~lycar~nate inthe block copolymer network, the better the chance for formation of co-continuous inter-locking networks on subsequent cooling. Therefore, it hasbeen found that when the block copolymer has a viscosity 3~7 -4&-n poise at temperature Tp and shear rate of 100 s 1, it is pref'erred that the engineering thermoplastic resin and/or thepo~ca~onate have such a viscosity at the temper-ature Tp and a shear rate of 100 s that the ratio of the viscosity O:e the block copolymer divided by the viscosity of the engineering thermoplastic and/orpolycarbonate be ~ , between 0.2 and ll.o, preferably between o.8 and 1.2.
Accordingly5 as used herein, isoviscous mixing means that the viscosity of the block copolymer divided by the viscosity of the other polymer or polymer blend at the temperature Tp and a shear rate of 100 s 1 is between ~ `
0.2 and 4Ø It should also be noted that within an extruder, there isawide distribution of shear rates.
Therefore, isoviscous mixing can occur even though the viscosity curves of two polymers differ at some of the shear rates.
In some cases, the order of mixing the polymers is critical. Accordin~ly. ~ne may choose to mix the block copolymer with the ~lyar~o~te or obher polymer first, and 2~ then mix the resulting blend with the dissimilar engineer-ing thermoplastic, or one may simply mix all the polymers at the same time. There are many variants on the order of mixing that can be employed, resulting in the multi-component blends of the present invention. It is also clear that the order o~ mixing can be employed in order to better match the relative viscosities of the various polymers~

-4g-The block copolymer or block copolymer blend may be selected to essentially match the viscosity Or thç
engineering thermoplastic resin and~or polycarbonate.
Optionally, the block copolymer may be mixed with a rubber compounding oil or supplemental resin as described hereinafter to change the viscosity charac-teristics Or the block copolymer. ~-The particular physical properties of the block copolymers are lmportant in forming co-continuous inter-locking networks. Specifically, the most preferred blockcopolymers when unblended do not melt in the ordinary sense with increasing temperature, since the vi~cosity of these polymers is highly non-Newtonian and tends to increase without limit as ~ero shear stress is approached.
Further, the viscosity Or these block copolymers is also relatively insensitive to temperature. This rheological behaviour and inherent thermal stability of the block co ;
polymer ehhances its ability to retain its network (domain) structure in the melt 50 that when the various blends are made~interlocking and continuous networks are formed.
The viscosltY.behaviour o~ the en~ineering thermoplastic resins, and ~carbonates on the other hand, is more sensitive to temperature than that Or the block copolymers. Ac-cordin~ly, it is often possible to select a processingtemperature Tp at which the viscosities o~ the block copolymer and dissimilar engineering resin and/or poly-ccr~on~e iall within the required range necessary to form interlocking networks. Optionally, a viscosity Inodlfier, as hereinabove described, may first be blended with the engineering thermoplastic resin orp~ycar~nate to achieve the necessary viscosity matching.
The ~end of partially hydrogenated block copolymer, ~lgcar~nate ald dissimilar engineering thermoplastic resin may be compounded with an extending oil ordinarily used in the processing of rubber and plastics. Especially preferred are the types of oil that are compatible with the elastomeric polymer blocks of the block copolymer.
While oils of higher aromatics content are satisfactory, those petroleum-based white oils having low volatility and less than 50% aromatics content as determined by the clay gel method (tentative ASTM method D 2007) are particularly preferred. The oils preferably have an initial boiling point above 260C.
The amount of oil employed may vary ~rom O to 100 phr ~ -(phr = parts by weight per hundred parts by weight of block copolymer), preferably from 5 to 30 phr.
The blend of partially hydrogenated block copolymer~
~l~carb~Qt-eand dlssimilar engineering thermoplastic resin may be further compounded with a resin. The additional resin may be a flow promoting resin such as an alpha-methylstyrene resin and an end-block plasticizing resin.

z~

Suitable end-block plasticizing resins include coumarone-indene resins~ vinyl toluene-alpha-methylstyrene co-po]ymers, polyindene resins and low molecular weight polystyrene resins.
The amount of additional resin may vary from 0 to 100 phr, prefer bly from 5 to 25 phr.
Further the composition may contain other polymers, ;~
fillers, reinforcements, anti-oxidantsg stabilizers~ -fire retardants, antl-blocking agents and other rubber and plastic compounding ingredients.
Examples of fillers that can be employed are mentioned in the 1971-1972 Modern Plastics Encyclopedia, pages 240-247.
Reinforcements are also useful in the present polymer blends. A reinforcement may be definecL as the material that is added to a resinous matrix to improve the strength of the polymer. Mos~ of these reinforcing materials are in-organic or organic products of high molecular weight.
Examples of reinforcements are glass fibres, asbestos, ~
boron fibres, carbon and graphite fibres, whiskers, quartz and silica fibres, ceramic fibres, metal fibres, natural organic fibres, and synthetic organic fibres. Especially preferred are reinforced polymer blends containing 2 to ~0 per cent by weight of glass fibres, based on the total weight of the resulting reinforced blend.
The polymer blends of the invention can be employed as metal replacements and in those areas where high performance is necessary.

-52~

In the illustrative Examples and the comparative Example given below, various polymer blends were prepared by mixing the polymers in a 3.125 cm Sterling Extruder having a Kenics Nozzle. The extruder has a 24:1 L/D
ratlo and a 3.8:1 compression ratio screw.
The various materials employed in the blends are listed below:
1) Block copolymer - a selectively hydrogenated block copolymer according to the invention having a structure S-EB~S.
2) Oil - TUFFLO 6056 rubber extending oil.
3~ Nylon 6 - PLASKON ~ 8207 polyamide.
4) Nylon 6-12 - ZYTEL ~ 158 polyamide.
5) Polypropylene - an essentially isotactic poly-propylene having a melt flow index of 5 (230C/2.16 kg).
6) Poly(butylene terephthalate) (PBT) - VALOX
310 resin.
~ 7) Polycarbonate - MERLON ~ M-40 polycarbonate.
8) Poly(ether sulphone) - 200P.

9) Polyurethane - PELLETHANE ~ CPR.

10) Polyacetal - DELRIN ~ 500.

11) Poly(acrylonitrile-~tyrene) - BAREX ~ 210.

12) Fluoropolymer - TEFZEL ~ 200 poly(vinylidene fluoride) copolymer.

323~
In all blends containing an oil component, the block copolymer and oil were premixed prior to the addition of the other polymers.
Illustrative Example I
. . .
Various polymer blends were prepared according to the invention. A blend of two block copolymers of higher and lower molecular weight was employed in some polymer blends in order to better match the viscosity with the poly-carbonate and/or other dissimilar engineering thermo-plastic resin. In some blends, an oil was mixed with the block copolymer in order to better match viscosities.
Comparative blends not containing a block copolymer were also prepared. However, these blends were not easily mixed. For example, blend 110 containing polycarbonate and Nylon 6 suffered from melt fracture and extreme die swell surging. In contrast, in each blend ~ontaining a block copolymer, the polymer blend was easily mixed, and the extrudate was homogeneous in appearance. Further, ln each blend containing a block copolymer, the resulting polyblend had the desired continuous, interlocking net-works as established by the criteria hereinabove described.
The compositions and test results are presented below in Tables 1 and 2. The compositions are listed in percent ?
by weight.

_ F~
.. ~. Jl ~ 23'7 o ~ ~

"'I '-- ~`
C~ .

o ~1 0 ~ L~
Cl~ I . .
o ~ ~ ~ .

~1 ` ~ r~ .
. .
~ ~ ~ .
~D

r~ ~, m ~1 o ~ ~1 E-l O
r~\ ~1 ~1 . ~ r- ~ .
o~ . . . ~

O I ~ L~
~1 ~ c--, , aJ
o ~
, ~ ~rl O ~ , I

. ~3 0 ~ ~ o a~
o q~ :>, ~1 a)~ ~ Q. " ~ -1~ ~ ~ :>~ O
~; o~I Q ~ , o O ~ Q a) ~ o ~, ~ ,~ ~ r~
!;: ~ O ~ O ~ a) ~ o :~, ~ ~ ~ ~ o o ~1 ~1 ~1 0 0 :>, O O O O O ~/
m m o P~ ~4 z ~, ~, ~ P~ ~ ~

5rj ~ IO Lf~ L~
O ~ t ~ Lr~ ~ ., . .
o t--o~l. .
Lr~

t_ O t-- N
- ~:

~ I Lr~ L~
O ~ t_ ~ L

~1 t_ ~,~
.
L~
~D
CO Lr~ L~
o t--O ~`
C>
IO L~ L~
C~
F~ l O t~
m ,~, ~ L~
CC
E~ ~1 ~ t_ . . .
L~
~ ~ ~D
a~l Lr~ L~
l ~ t~ :

~ I
~ r~
o ~
rl o a r-l ta ~: a) r~ O O Ei Q ~:~ c> r~ r~ r~
. ~ O U~ ~ ~ ~ O (Ll ~
O ~ ~ r~ ~ J~ ~ ~ ~ ~ J~ ~ !:1 ~ O
æ O ~ Q a) ~ 0 ~
r~ ~ Q ~ ~ ~ O
~ ~ rl ~ ~ ~ O ~
O a) O r~ O ~1 0 r I ~i ~I r~l r-l r~ r1 0 ~1 r~ c) ~rl ~ O ~ O ~ O O O O O c) r~l ~Q ~ O P ~

O O U~ ~1 ~ t-- ~ ~ ~ ~ ~ ~
3~ 3~ J J ~ O a~ 3~
'-I ~ O ~ ~1 r! ~ 1 ~1 0 ~ ~ O
o o o o o o o O O O O o OOOooOOOO OOO
C~ ¦ ~IL~ J 3 ~ N ~\ O O ~ CO
., .
~ ~ 03~~ 0 3 ~ Cl`\ If\ ~_ O O O OO O O O O O O O
O O O OO O O O O O O O
O ~~Or~ ~ ~ ~ 3 1~ 0 ~D

o I I I~oo~ O~O

OOOOOOOOO OOO
O O O O O O O O O O O O
t-- ~o ~ ~~o O O~1~1 ~ CO ~O '~
~1 o ~ o ~ 1-- =t c~ ~1 ~ . . . . . . . . .

O O O~`JO~1~0 L~ 0~ h'~
N h'~ CO O ~t~ D CO 1 ~J ~ 'IC O O
~c m m m m m m o m m o m m ~ ~1 1 Z Z; Z Z Z Z ~ Z Z o~ Z Z
'C h'~ CO
E~ ~
a~
~:
c~
o ~
~1 0 OL-~ O Oh-~ O O h--\ O O h-- O
m O

a) a) m ~~ a) o S~ ~ ~ ~ O
a~ a) o o Z
o :,, ~ o o ~ o ~ ,~ m z P~ u~' ~ ~ a) ~d . O ~ 1 ~ 3 zm a~ o ~ o ~ ~o o~
m Z ~ ~ ~ ~0 ~ o 3~ 1 ~ '3~ ~ 3 . . .
~ ~ ~1 0 ~38~37 o o o o o o o ~, ~ o o o CO I ~ ~ o ~C) 3 ~ 1--~ 1 ~1 1-- 3 ~
a~ ~ ~1 ~ O~t g g 8 o g g 3 0 ~) ~ C'- Lr\
~1 ~1 m m m L~l 3 LS~ ~D ~ ~; Z

g g g o g ::
~D J ~D J1 o J O 1 O ~ ~
`J ~ 03 .
O 3 (~J ~\J~I t`J ~1 O O O ~C
cu ~c ~ o o m m m ~1 ~ ~ '~ Z Z
a~
E~ . $~ : ' C~ ~ ~ .
o ~ o ~ o o U~ o -:
m f' ~ ~ ~ ~ .
~C~
~ a~
;~, ~
m 1~ C!) a) o a~ c) S~ Z
, .
o o o P~ ~ :4 ~ a ~;
. m c~:7 ~ 3 ~ Ll~
a) o o c~ ~ oo~ o~
~Z
m :

~57--5~3--;23'7 co O o ~ ~~ o ~ ~o ~ L~
J~ ~LS~ ~ ~) 31-- L(~ ~o ~O O t-- CC~
t~ L
~ O O ~1 0 ~1 ~ C) ~ ~ ~ 3 c) F~
~0 3 3 0 ~ 3 -~Cl~ ~ ~ ,`r, Q, O ~ ~1 3 c~ r~ o O
o H I ~1 O O ~1 0 ~1 ~I ol ~I cc) ~I r~ c~
~1 O L~ L~ 3 ~ O O
3co ~ t-- ~ ~ ~1 ~o 1--c~ O
L~
O~1 ~ o ~ co 3 t~
U oco ~ 3 o ~
00 ~ 3 0 L ~ Lr~ co L~\ ~o o~ o ~1 ~3 H (~I ~1 O ~ O ~ o 3 o ~1 ~1 ~`

~ o co 3 N 3 ('J L(~ co r~\ ~1 O~ ~ (\1 O ~o ~1 (~ L~ J O

~o o ~ ~ o ,_ O O O O O O O O O O O O

- 3 (~ 3 ~J 3 o co L(~
-1~ LOCO 3 ~1 ~ t\~ t-- 3 L~
~:~1 o ~1 ~ a- :~ Lf~ 3 3 ~t 3 ~ ::11~\
C) 3 0 ~ 3 C~
~I O ~ ~ ~ ~-- CO ~ 1~ ~t ~1 (~ J N (~
~:1 m E~C) o~
o o Lr~ o o L~ o o L~ o o Ll~ o m ~
o C) . `~

Q. F~

a~
a~ o ~o ~ s~
a~ a) o o ?~ O ~>~ ~ O
r-l r I ~ ~1 ~ E~
o :~, o ~ ~ m F~ æ F~ u~ ' F~
~:1 O ~1 01 ~11~ 3 0 L~ ~o ~ ~1 (~
a) o ~Ico co ~Ico co ~ co co o Z ~ ~1 m 39i3~237 ~ a~
a~
~1 ` L~\ ~D L(~
Q
~0 ~D
Ql O(\J 1~L~ ~ Lf~ C~
D
H I ~1~ rL~

~1:~ ~IL~\ CO~) Q
L~l Ir~ J CO ~,q -I J
O
L~ u ~ L~
00 :~(~ICO Il) ~1 N ~ :~ Lr~ cr, ~ ~
t~l L~ .
O ~C ' Q~ ~; C~ C) C.) C) X
O O C~ ~ 0~ ~ L~
1 ~ o t-- ~D C~L~
o o a) Q Q Q
~C O
O ~1 ~1~1 u~ d r~ r~ r~ rH
~I. . . . . .;~, o Q, o ,~
~1O O O O O O
Qr~ 'C~ ~ ~) D~ r~ ~r~
Oa:~ L~i COr~l ~ h ~ ~ ~ ~ ~ ~ o r r~

( U ~ ~ L~O rX
O0;~ L~L~ O ~1 ~ 1~ ~ L~
m : ~
CC L~
E~ O L~
~ ~ O
a) ~ .
~ ~ ~ .
O H OL~\O OL~\ OU~ tQ r-l r--l O ~ r, ~1 ~ ~D Q,U~~ r-l m ~ ~ Q U~ ,_, L~
O ~r~ ` Q~ O O
~,~ ~ ~ r~
a) (I) ~L
~ ,, ,5::~ r~
;>~ r~ t~ P 5 r~ r~rlrl r1 ~ a~ ~ ~ O rn~ntn .~ ~ O ~ rlr~ ~1 4 Q~
r~_~ a, O ~ ~ ~ OU~ (1) ~:
a) ~ ~i Q
E~ ~ o r-l r-l ~ r~ H _ O O O, t~U~ ~ ~ r-lr~ rl ~rl .
J~ ~ ~ x ~ x ~ O o a) rl~) ~1 0 ~ -1~1 E~
r~, . ~ a C-L~ ~D
a~ o o c~ o a~
r-l Z~1 ~1 ,~ . . . . . . . . ::
m ~ ~ L~

~9~

o LS~ "~
CO
o o ~r~
ci~ u~
~ ~ ~ :

o ~ .,~
~1 o ~
~ ~ ~ , o ~ ,~, t_ Ll~ ~ ~

r, O O O ~, , ~1 o u~
r~
¢m E~ . ~, o I
~h`~."
~ .
, a) ~, : . , o a) ~ a~
o ~~d !~
d ~1 . o ~ ~ O ~
O ~ ~ ~ ~> ~ ,9 h h ~; O >~ 0 ~1 ,~ ~ d ~d ~:) ~:) o S: S~ ~ O
a~ a) c) ~1 ~~1 ~1~1 ~1 o C) o ~ o ~ o o C~
m m ~ ~ z P~

, ._ o o ~D Lt~ Lt~
r- ' O O ~
~1 Lt~ Lt~
~ 1~ (~J :
O , '' CC) LS~ L
OC~ ~ ~

O Lt~ L~
O~
O O
N ~ Lt~ ;

, o Ir~ Lt~ , . . . .
o Lt~
~I ~-I S 3 ~ :
O :~
O O O ~ ' ~
O
15~ ~ S
~1 ~ LS\ ~\
m C
E~
o ~ ~
3 . . . : '.
'~ ` ` .
~1 ~ ~ "

t~) :
~rl ~ ` ;`' ~Itn a) ~1a) , 0 0 Q h . o ~ ~ ~ o ~ ~ .: , : ` ' O ~ Q. Q h h Z O ~ ~ 5:~ O ~D hc) ~ :``
r I Q Q, o Q~ ~ ~ ~ O
o a~o ~1 a~ .~ .~,~ ~ o `:
C~ O ~ o ~ o oC) m m ~ ~ ~ ~
:

~.

-~2~

The results of the above blends indicate the un-obvious properties for the present blends. For example, by comparing blend 109 with blends 91 and 92, it can be seen that at a ratio of polycarbonate to PBT of 3:1, by increasing the amount of' the block component from 0 to 15 to 30%, the heat distortion temperature does not drop as one would expect instead, the heat distortion temper-ature is actually higher in blends containing the block copolymer than in blend 109 not containing the block co-polymer. Typically, when adding an amorphous rubber to a thermoplastic~ one would expect a significant decline in heat distortion temperature since the heat distortion temperature of the rubber is very low.
It is also important to note that with increasing amounts of block copolymer, the Izod impact strength in- -creases significantly while the heat distortion temper-ature is not significantly effected. This is dramatically ~ ;
shown by comparing the ratio of the percent increase in impact strength divided by the percent change in heat distortion temperature. For example, by examining the ratio of the relative increase in Izod impact strength (at 23C) over ~he relative decrease in heat distortion ~:
temperature for polymer blends as the percentage of block copolymer is increased from 0% to 15% at a fixed 3:1 ratio polycarbonate to dissimilar engineering thermoplastic, it can be seen that much larger than -63- ~ 2 3 ~

expected values are obtained. One ski]led in the art would typically expect this value to be positive and less than 1. However, for blends containing nylon 6, a fluorinated copolymer, a polyacetal, and poly(butylene terephthala-te), the ratios are minus 142, minus 23, 28 and minus 37. The minus values are particularly out-standing since these represent an increase in heat distortion temperature with an increase in block co-polymer.
Illustrative Example II
~arious additional blends were prepared in a similar manner to those in illustrative Example I.
The various blends are presented in Table 3. In all cases containing a block copolymer, the polyblends possessed the desired interlocking network structure.

' ' ~, .' : ' -; ~

Claims (33)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1 A composition containing a partially hydrogenated block copolymer comprising at least two terminal polymer blocks A of a monoalkenyl arene having an average molecular weight of from 5,000 to 125,000, and at least one intermediate polymer block B of a conjugated diene having an average molecular weight of from 10,000 to 300,000, in which the terminal polymer blocks A constitute from 8 to 55% by weight of the block copolymer and no more than 25% of the arene double bonds of the polymer blocks A and at least 80% of the aliphatic double bonds of the polymer blocks B have been reduced by hydrogenation, characterized in that the composition comprises:
(a) 4 to 40 parts by weight of the partially hydrogenated block copolymer, (b) a polycarbonate having a melting point over 120°C, (c) 5 to 48 parts by weight of at least one dissimilar engineering thermo-plastic resin being selected from the group consisting of polyamides, polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones), acetal resins, thermoplastic polyurethanes, halogenated thermoplastics, and nitrile resins, in which the weight ratio of the polycarbonate to the dissimilar engineering thermoplastic resin is greater than 1:1 so as to form a polyblend wherein at least two of the polymers form at least partial continuous interlocked networks with each other.

2. A composition as claimed in claim 1, in which the polymer blocks A have a number average molecular weight of from 7,000 to 60,000 and the polymer blocks B have a number average molecular weight of from 30,000 to 150,000.

3. A composition as claimed in claim 1 or 2, in which the terminal polymer blocks A constitute from 10 to 30% by weight of the block copolymer.

4. A composition as claimed in claim 1, in which less than 5% of the arene double bonds of the polymer blocks A and at least 99% of the aliphatic double bonds of the polymer blocks B have been reduced by hydrogenation.

5. A composition as claimed in claim 1, in which the polycarbonate has the general formula:
I
II

wherein Ar represents a phenylene or an alkyl, alkoxy, halogen or nitro-substituted phenylene group, A represents a carbon-to-carbon bond or an alkylidene, cycloalkylidene, alkylene, cycloalkylene, azo, imino, sulphur, oxygen, sulphoxide or sulphone group, and n is at least two.

6. A composition as claimed in claim 1, in which the dissimilar engineering thermoplastic resin has an apparent crystalline melting point in excess of 120°C.

7. A composition as claimed in claim 6, in which the dissimilar engineering thermoplastic resin has an apparent crystalline melting point of between 150°C and 350°C.

8. A composition as claimed in claim 1, in which the composition contains an isotactic polypropylene.

9. A composition as claimed in claim 1, in which the composition contains poly(1-butene) as polyolefin.

10. A composition as claimed in claim 1, in which the dissimilar engineering thermoplastic resin is a thermoplastic polyester having a melting point in excess of 120°C.

11. A composition as claimed in claim 1 and 22, in which the dissimilar engineering thermoplastic resin is poly(ethylene terephthalate), poly(propylene terephthalate) or poly(butylene terephthalate).

12. A composition as claimed in claim 11, in which the dissimilar engineering thermoplastic resin is poly(butylene terephthalate) having an average molecular weight in the range of from 20,000 to 25,000.

13. A composition as claimed in claim 1, in which the dissimilar engineering thermoplastic resin is a polyamide having a number average molecular weight in excess of 10,000.

14. A composition as claimed in claim 1, in which the engineering thermoplastic resin is a polyacetal copolymer.

15. A composition as claimed in claim 1, in which the engineering thermoplastic resin is a homopolymer or copolymer derived from tetrafluoro-ethylene, chlorotrifluoroethylene, bromotrifluoroethylene, vinylidene fluoride and vinylidene chloride.

16. A composition as claimed in claim 1, in which the engineering thermoplastic resin is a nitrile resin having an alpha,beta-olefinically unsaturated mononitrile content of greater than 50% by weight.

17. A composition as claimed in claim 16, in which the alpha,beta-olefinically unsaturated mononitrile has the general formula wherein R represents hydrogen, an alkyl group having from 1 to 4 carbon atoms or a halogen.

18. A composition as claimed in claim 1, in which the composition contains the block copolymer and the dissimilar thermoplastic resin in an amount of from 8 to 20 parts by weight and from 10 to 35 parts by weight, respectively.

19. A composition as claimed in claim 1, in which the composition contains an extending oil in an amount of from 0 to 100 phr.

20. A composition as claimed in claim 19, in which the composition contains an extending oil in an amount of from 5 to 30 phr.

21. A composition as claimed in claim 1, in which the composition contains a flow-promoting resin as additional resin in an amount of from 0 to 100 phr.

22. A composition as claimed in claim 21, in which the composition contains a flow-promoting resin as additional resin in an amount of from 5 to 25 phr.

23. A composition as claimed in claim 21 or 22, in which the com-position contains an additional resin selected from the group consisting of an alpha-methylstyrene resin, coumarone-indene resins, vinyl toluene-alpha-methylstyrene copolymers, polyindene resins and low molecular weight polystyrene resins.

24. A process for the preparation of a composition as claimed in claim 1, characterized in that (a) 4 to 40 parts by weight of a partially hydrogenated block copolymer comprising at least two terminal polymer blocks A of a monoalkenyl arene having an average molecular weight of from 5,000 to 125,000, and at least one intermediate polymer block B of a conjugated diene having an average molecular weight of from 10,000 to 300,000, in which the terminal polymer blocks A constitute from 8 to 55% by weight of the block copolymer and no more than 25% of the arene double bonds of the polymer blocks A and at least 80% of the aliphatic double bonds of the polymer blocks B have been reduced by hydrogenation, are mixed at a processing temperature Tp of between 150°C and 400°C with (b) a polycarbonate having a melting point over 120°C, and (c) 5 to 48 parts by weight of at least one dissimilar engineering thermo-plastic resin being selected from the group consisting of polyamides, polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones), acetal resins, thermoplastic polyurethanes, halogenated thermoplastics and nitrile resins, in which the weight ratio of the polycarbonate to the dissimilar engineering thermoplastic resin is greater than 1:1 so as to form a polyblend wherein at least two of the polymers form at least partial continuous interlocked networks with each other.

25. A process as claimed in claim 24, characterized in that the polymers are mixed at a processing temperature Tp of between 230°C and 300°C.

26. A process as claimed in claim 24 or 25, characterized in that the polymers are dissolved in a solvent common for all and coagulated by admixing in a solvent in which none of the polymers are soluble.

27. A process as claimed in claim 24 or 25, characterized in that the polymers are mixed as granules and/or powder in a device which provides shear.

28. A process as claimed in claim 24, characterized in that the ratio of the viscosity of the block copolymer divided by the viscosity of the poly-carbonate, the dissimilar engineering thermoplastic resin or the mixture of the polycarbonate and the dissimilar engineering thermoplastic resin is between 0.2 and 4.0 at the processing temperature Tp and a shear rate of 100 s-1.

29. A process as claimed in claim 28, characterized in that the viscosity ratio of the viscosity of the block copolymer divided by the viscosity of the polycarbonate, the dissimilar engineering thermoplastic resin or the mixture of the polycarbonate and the dissimilar engineering thermoplastic resin is between 0.8 and 1.2 at the processing temperature Tp and a shear rate of 100 s-1.

30. A process as claimed in claim 24, characterized in that the dissimilar thermoplastic resin is first blended with a viscosity modifier before blending with the polycarbonate and the block copolymer.

31. A process as claimed in claim 24, characterized in that as viscosity modifier poly(2,6-dimethyl-1,4-phenylene)oxide, or a blend of poly-(2-6,dimethyl-1,4-phenylene)oxide with polystyrene is used.

32 A process as claimed in claim 30 or 31, characterized in that the viscosity modifier is used in an amount of from 10 to 50 parts by weight per 100 parts by weight of engineering thermoplastic resin.

33. A process as claimed in claim 24, characterized in that the block copolymer and the dissimilar engineering thermoplastic resin are used in an amount of from 8 to 20 parts by weight and from 10 to 35 parts by weight, respectively.