CA1098238A - Compositions containing hydrogenated block copolymers and engineering thermoplastic resins - Google Patents

Abstract

A B S T R A C T

In a composition containing partially hydrogenated block copolymer, a polyacetal 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

1323~

The invention relates to a composition containing a partially hydrogenated block copolymer comprising at least two terminal polymer blocks A o~ a monoalkenyl arene having an average molecular weight of rrom 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% o~ the arene double bonds of the polymer blocks A
and at least 80% of the aliphatic double bonds o~ 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,~
stirfness, 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, ror example, in automotive applicationsO
For a particular application, a single thermoplastic resin may not offer the combination of properties de8ired and, thererore, means to correct this deficiency are of interest. One particularly appealing route is through blending together two or more polymers tWhich individually have the properties sought~ to give a material with the desired combination of properties. ~his approach has been ... . . . ,_ .. , . .. . , , , ~

successful in limited cases, such as in the improvement of impact resistance for thermoplastic resins, e.g. 9 polystyrene, polypropylene and poly(vinyl chloride), using special blending procedures or additives for 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 bein~ a material Or 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 te~ches that most combinations of polymer pairs are not miscible, although a number of notable exceptions are known. More importantly, most polymers adhere poorly to one another. As a result, the interfaces between componenk domains (a result of their immiscibility) represent areas of severe weakness in blends and, thereforel provide natural flaws and cracks which result in facile mechanical failure. Because of this, most polymer pairs are said to be "incompatible". In some instances the term compatibility is used synonymously with miscibility, however, compatibility ls 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.

3~
-Ll_ 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, often referred to as a "compatibilizing agent", that possesses a dual solubility nature for the two polymers to be blended.
Examples Or this third component are obtained in block or graft copolymers. As a result Or this characteristic, this agent locates at the interface between components and grea~ly improves interphase adhesion and therefore increases stabil:ity to gross phase separation.
The invention 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 solubil:ity characteristics.
The materials used for this purpose are special block co-polymers capable of thermally reversible self-cross linking.
~heir action in the present invention i5 not that visuali~ed by the usual compatibilizlng concept as evidenced by the general ability of these mate~ials to perform similarly for a wide range of blend components which do not conform to the solubility requirements of the previous concept.
Now, the invention provides a composition containing a partially hydrogenated block copolymer comprising at least two terminal polymer blocks A o~ a monoalkenyl arene having an average molecular weight Or from 5,000 to 125,000, and at least one intermediate polymer block B of a con-jugatecl 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, which composition is characterized in that the composition comprises:
~a) 4 to 40 parts by weight of the partially hydrogenated block copolymer;
(b) an acetal resin having a generally crystalline structure and a melting point over 120C;
(c) 5 to 48 parts by weight of at least one dissimilar engineering thermoplastic resin being selected from the group consisting of polyamides, : ;
polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones~
polycarbonates, thermoplastic polyurethanes, halogenated thermoplastics, and nitrile resins, in which the weight ratio of the acetal resin 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.

In another aspect, the invention provides a process for the preparation of a composition as claimed above 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 temp0rature ~p of between 150C and 400C with (b) an acetal resin having a generally crystalline structure and a J
.~

melting point over 120C, and (c) 5 to 4~ parts by weight of at least one dissimilar engineering thermoplastic resin being selected from the group consisting of polyamides, polyolefins, thermoplastic polyesters, poly(aryl ethers), poly~aryl sulphones), polycarbonates, thermoplastic polyurethanes, halogenated thermoplastics and nitrile resins, in which the weight ratio of the acetal resin 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.
The block copolymer of the invention ef~ectively acts as a mechanical or structural stabili~er which interlocks ., .

- 5a -,, ~JJ

~9~23 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 Or at least two partial continuous interlocking networks. This interlocked structure resu]ts in a dimensionally stable polyblend that wil] not delaminate upon extrusion and subsequent use.
To produce stable blends it is necessary that at least two Or 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 polymers 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) o~the partial continuous network is continuous. As can be readily seen, a large variety Or blend structures is possible since the structure of the polymer in the blend may be completely continuous, completely disperse 9 or partially continuous and partially dispexse. Further yet, the disperse phase of one polymer may be dispersed in a -7~

second polymer an~] not in a third polymer. To illustrate some of the structures, the following lists the various combinations of polymer struc-tures 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 "d" signifies a disperse structure. Thus, the designation "QcB" 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
Th~ ice o~ the invention, it is possiOle .. . .. .. ..

-7a~ %3~

to improve one ~ype of physical property of the composite bl.end while not causing a significant deterioration in another physical property. In the past this has not always been possible. ~'or 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 strengthg 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. However, in the present invention it is possible to significantly improve impact strength while not detracting from the heat di.stortion temperature. In fact, when the relative increase in Izod impact strength is measured against the relative decrease in HDT, the value of the ratio is much higher than one would expect. For example, in blends containing a polyacetal, block copolymer, and other engineering thermoplastics such as PBT and polycarbonates, this ratio is greater than 10~ whereas one would typically expect positive values of less than 1.

- _ :

, ., . .. ,,, . . , .... , _ ... .

It is particularly surprising that even just small amounts of the block copolymer are sufficient to stabillze the structure of the polymer blend over very wide relative concentrations. ~or example, as little as four parts by weight of the block copolymer is sufricient to stabilize a blend of 5 to 90 parts by weight polvacetal with 90 to 5 parts by weight of a dissimilar engineering thermoplastic.
In addition, it is also surprising that the block co-polymers are US~ f`ul 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 o~ polymer over a wide range Or concentrations since they are oxidatively stable a possess essentially an infinite viscosity at ~ero shear stress, and retain network or domain structure in the melt.
Another significant aspect of the invention is that the ease of processing and ~orming 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 o~ geometrical structure, since the invention does not depend on any specific geometrical structure, but rather upon the chemical constitution of each of the polymer blocks. Thus3 the block copolymers may be llnear, radial or branched.
Methods for the preparation of such polymers are known in ~ 8~

g :

the art. The structure of the polymers is determined by their methods of polymerization. For example, linear polymers result by sequential introduction of the desired monomers into the reaction vessel when using such initiators as lithium-alkyls or dilithio-stilbene, or by coupling a two-segment block copolymer with a difunctional coupling agent. Branched structures,on the other ~and, may be obtained by the use Or 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 Or the compositions of thls invention.
Likewise, in the generic sense, the specific structures also may be ignored. The invention applies especially to the use of selectively hydrogenated polymers having the configuration before hydrogenation o~ the following typical. species:
polystyrene-polybutadiene-polystyrene (S~S) polystyrene~polyisoprene-polystyrene ~SIS) poly(alpha-methylstyrene)polybutadiene-poly(alpha-methylstyrene) and ~13231 poly(alpha-methylstyrene)polyisoprene-poly(alpha-methylstyrene).
Both polymer blocks A and B may be either homopolymer or rando~ copolymer blocks as long as each polymer block predominates in at least one class o~ the monomers charac terlzing the polymer blocks. The polymer block A may comprise homopolymers of a monoalkenyl arene and co-polymers of a monoalkenyl arene with a conjugated dlene as long as the polymer blocks A individually predomlnate in monoalken~l arene units. ~he term l'monoalkenyl arene"
; will be taken to include especially styrene and its analogues and homologues including alpha-methylstyrene and ring-substituted styrenes, particularly`ring-methyl-ated styrenes. The preferred monoalkenyl arenes are styrene and alpha-methylstyrene, and styrene is particularly preferred. The polymer bLocks B may comprise homopo]ymers of a conjugated diene, such as butadiene or isoprene~ 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 monomeremployed is butadiene, it is preferr~d 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 ~S3~ 3~

isoprene, the resulting hydrogenated product is or resembles a regular copolymer block of ethylene and propylene (EP~.
Hydrogenation o~ the precursor block copolymers is preferably efrected by use Or a catalyst comprising the reaction products of an aluminîum alk~l compound with ; nickel or cobalt carboxylates or alkoxides under such conditions as to substantially completely hydrogenate at least 80% of` the aliphatic double bonds, while hydrogenating no rnore than 25% of the alkenyl arene aromatic double bonds. Preferred block copolymers are those where at least 99~ o~ 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-polymer present in the composition 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 125,000, preferably from 7,000 to 60,0007 and at least one interrnediate polymer block B
of a conjugated diene having a number 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 tritiurn counting methods or osmotic pressure measurement s .

~Y18;~3~

The proportion of the polymer blocks A of the mono-alkenyl arene should be between 8 and 55% by weight of the block copolymer, preferably between 10 and 30% by w~v~

.. , . , .. . . _ . ~ . . . .......... . ..... . . .

~13-The acetal resins present in the.com-positions according to the invention include the high molecular weight polyacetal. homopolymers made by polymer-izing formaldehyde or trioxane. These polyacetal homo- :
polymers are commercially available under the trade ~ffl~
DELRIN ~f. A related polyether-type resin is available ~:
~0~
under the trade ~ PENTON ~ and has the structure: :
_ ~ .
CH2C1 , _ _o C112 C--C~12- ~' ; :
n The acetal resin prepared frorn formaldehyde has a high molecular weigh~ and a structure typified by the following:
'~

- H- O- ( C'H~- O -CH2- O) ~ -H

where terminal groups are derived from controlled amounts Or ~ ~;
water and the x denotes a large ~prererably ~500) number Or ~-formaldehyde units linked in ~lead~to-tail fashion. To in-crease thermal and chemical resistance, terminal groups :~ :
are typically converted to esters or ethers. . ~`
Also included :in the term polyacetal resins are the polyacetal copolymers. These copolymers include block co- ~ :
po].ymers of formaldehyde with monomers or prepolymers Or other materials capable of providing active hydrogens, 3;23~ -1 Ll -such as alkylene glycols, polythio]s, vinyl acetate-acrylic acid copolymers, or reduced butadiene/acrylonitrile polymers.
~ Celanese has commercially available a copolymer of 5 ~ formaldehyde and ethylene oxide under the trade ~me CELCON
that is useful in the blends of the present invention. ~hese copolymers typically have a structure comprising recurring units having the formula:

_Lo wherein each R1 and R2 is selected from the group consisting ; 10 of hydrogen, lower alkyl and lower halogen substituted alkyl radicals and wherein n is an integer from zero to t~lree and wherein n is zero in from 85% to 99.9% of the recurrln units.
Formaldehyde and trioxane can be copolymerized with other aldehydes, cyclic ethers, vinyl compounds, ketenes, cyclic carbonates, epoxides, isocyanates and ethers. These compounds include ethylene oxide, 1,3-dioxolane, 1,3-dioxane, 1,3-dioxepene, epichlorohydrin, propylene oxide, isobutylene oxide, and styrene oxide.

- ili~l~;~38 The term "dissimilar engineering thermoplastic resin"
refers to engineering thermoplastic resins different from those encompassed by the polyacetals present in the com-positions according to the invention.
The term "engineering thermoplastic resin" encompasses the various polymers found in the classes listed in Table A
below and thereafter defined in the specification.

TABLE A
1. Polyolefins

2. Thermoplastic polyesters

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

4. Polycarbonates

5. Polyamides ;

6. Thermoplastic polyurethanes

7. Halogenated thermoplastics

8. Nitrile resins Preferably these engineering thermoplastic resins have glass transition temperatures or apparent crystalline melting points (defined as that temperature at which the modulus, at low stress, shows a catastrophic drop) of -~
o~er 120C, preferably between 150C and 350C, and are capable of forming a continuous network structure through a thermally reversible cross-linking mechanismO
Such thermally reversible cross-linking mechanisms in-clude crystallites, polar aggregations, ionic aggregations, lamellae, or hydrogen bonding. In a specific embodiment~

3~
where the viscosity of the 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 ~ may be between 0.2 and 4.0, preferably 0.8 and 1.2. As used in the specification and claims3 the viscosi-ty of the block copolymer, polyacetal 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 procesaed 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 thermoplast;ic resins and blends with additional viscosity modifying resins.
These various classes of engineering thermoplastics are defined below.
The polyolefins~ if present in the compositions 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 polyolefins include ,, ~
low-density polyethylene~ high-~ensity polyethylene, iso-tactic polypropylene, poly(1-butene)~ poly(4-methyl-1-pentene), and copolymers of Ll-methyl-1-pentene wlth 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 polymer blend according to the invention. The number average molecular weight of the polyolefins may be above 10,000, preferably above 50,000.
In addition, the apparent crystalline melting point may be above 100C, preferably between 100 C and 250C, and more preferably between 140C and 250C. The preparationsof these various polyolefins are well known. See generally "Olefin Polymers", Volume 14, l~irk-Othmer Encyclopedia of Chemical Technology, pages 217-335 (1967)~
When a high-density polyethylene is employed, it has a- ~I r~ crystallinity of over 75~ and a density in ~ : -`'`` ~. \ ' :

~ 3 kilograms per litre (kg/l) of between 0.9ll and 1.0 while when a low density polyethylene is employed, it has an approximate crystallinity of over 35% and a density Or between 0.90 kg/l and 0 94 kg/l. The composition ac-cording to the invention may contain a polyethylene havinga number average molecular wei~ht of 50,000 to 500,000.
When a polypropylene is employed, it is the sa-called isotactic polypropylene as opposed to atactic polypropylene. The number ~verage molecular weight Or the polypropyle~ne erl~ploye(lr~Y~eineXcess Or loo,ooo. The ~oly-propylene may b~ prepared using methods of the prior art. Depending on the specific catalyst and polymer- -i~ation 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 o~
low atactic content that crystalliæe mo~e completely.
The preferred cornrnercia] polypropylenes are generally prepared using 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 aluminiurn chloride. If desired, the polypropylene employed is a copolymer containing rninor (1 to 20 per cent by weight) amounts Or ethy]ene or another alpha-olefin as comorlomer.

3~323~

The poly(l-butene~ preferably has an isotactic structure.
The c talysts used in preparing the poly(l-butene) are preferably organo-metallic compounds commonly referred to .
as Ziegler--Natta catalysts. A typical catalyst is the interacted product resulting from mixing equimalar quan-tities of titanium tetrachloride and triethylaluminium.
The manufacturing process is normally carried out in an inert diluent such as hexane. Manufacturing operations, in all phases of polymer rormation~ are conducted in such a manner as to guarantee rigorous excluslon of 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-nlethyl-1-pentene is commercially manufactured by the alkali-metal catalyzed dimer:ization of propylene. The homopolymerization Or 4-methyl-1-pentene with Ziegler-Natta catalysts is descrlbed in the Kirk-Othmer Enclopedla Or Chemical Technology~
Supplement volume, pages 789-792 (second edition, ly7 However, the isotactic homopolymer Or 4 methyl-l-pentene has certain technical derects, such as brittleness and~ ~ -inadequate transparency. Therefore, commercially available poly(4-rnethyl-1-penterle) is actually a copolymer with -minor proportions of other alpha-olefins, together with the addition Or suitable oxidation and melt stabilizer ......... . .. ... . ..... .. . . ..

3~
-~o-systems. These copolymers are described in the Kirk-Othmer Encyclopeclia of Chemical Tecynology, Supplement volume~ pages 792-907 (second edition, 1971)~ and are ~ available under the trade ~ 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 desiredg 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.

3~

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 thereo~ with a glycol, according to methods well known in -the art.
Among the aromatic and aliphatic dicarboxylic acids sui.table for preparing polyesters are oxalic acid, malonic acid, succinic acid, g]utaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, iso-phthalic acid, p carboxyphenoacetic acid, p,p'~icarboxydiphenyl, p~pl-dicarboxydiphenylsulphone, p-carboxyphenoxyacetic acid, p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyric acid, p carboxyphenoxyvaleric acid, p-carboxyphenoxyhexanolc acid~, -p,~'-dlcarboxydiphenylmethane, p~p-dicarboxydiphenylpropane, p,p'-dicarboxydiphenyloctane, 3~alkyl-4-(~-carboxyethoxy)-benzoic acid, 2,6-naphthalene dicarboxylic acid, and 2,7-naphthalene dicarboxylic acid. Mixtures Or dicarboxylic acids can also be employed. Terephthalic acid is particularly preferred.
The glycols suitable ~or preparing the polyesters include straight-chain alkylene glycols of 2 to 12 carbon atoms, such as ethylene glycol, 1,3 propylene glycol, 1,6-hexylene glycol, l,10-decamethylene glycol, and 1,12-dodecameth~lene glycol. Aromatic glycols can be substituted in whole or in part. Suitable aromatic dihydroxy compounds include p-xylylene glycoll pyrocatechol, resorcinol, 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 po:Lyesters are poly(ethylene terephthalate), poly(propylene terephthalate), and poly-(butylene terephthalate). A much preferred polyester is poly(butylene terephthalate). Poly(butylene terephthalate)j a crystalline copolymer, may be formed by the po]ycondensatlon of` l,ll-butanediol and dimethyl t-rephtha]ate or terephthalic acid, and has the generalized formula:

~C--~,3--C--O--~C~

n where n varies lro~ 70 to 140. The average molecular weight of the poly(butylene terephthalate) preferably varies from 20,000 to 25,000.
Commercially available poly(butylene terephthalate) is ~Of~
D available under the trade ~ 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 mouldin~, coatin~ and film forming materials .. . ..... .. _ _ _ . .... ......

and are well known. These materials include the solid thermoplastic forms Or cellulose nitrate, cellulose acetate (e.g., cellulose diacetate, cellulose tri-acetate), cellulose butyrate, cellulose acetate butyrate, cellulose propionate, cellulose tridecanoate, carboxy methyl cellulose, ethyl cellulose, hydroxyethyl cellulose and acetylated hydroxyethyl cellulose as described on pages 25-28 of Modern Plastics Encyclopedia~ 1971-72, and references listed therein.
Another useful polyester is a polypivalolactone. Poly-pivalolactone is a linear polymer having recurring ester structural units ~ainly Or the formula:

- -CH C(CH ~ -C(0)0 -i.e., units derived from pivalolactone. Preferably, the poly-ester is a pivalolactone homopolymer. Also included~ however,~are the copolymers of pivalolactone with no more than 50 mo].~, preferably not more than 10 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 "heta-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. ~specially pre~erred are the alpha,alpha-dialkyl-beta-propiolactones wherein each of the alkyl groups independently has from one to four carbon atoms.

. .
Examples of useful monorners are:

alpha ethyl-alpha-methyl-beta-propio:Lactone, alpha-methyl-alpha-isopropyl-beta-propiolactone~
alpha-ethyl-alpha-n-butyl-beta-propiolactone, alpha-chloro~ethyl-alpha-methyl-beta-propiolactone, alpha~alpha-bls(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~
O ~ ~ .
t CH2 c~12 CH2 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 en~ineer-ing thermoplastic resins. The poly(aryl polyethers) which may be present in the composition according to the invention include the linear thermoplastic polymers composed of re-curring units having the formula:

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

323~

and - ~ R~ ~ 3 III

wherein R represents a bond between aromatic carbon atoms, ~.
O , S , S- s-,or a divalent hydrocarbon radical having ~rom 1 to 18 carbon atoms inclusive, and G' i5 the residuum of a dibro~no or di-iodobenzenoid compound selected ~rom the group consistine Or:

~ IV

and _~_p~,~3 V ~' ~

wherein R' represents a bond between aromatic carbon atoms, - O- , - S , -S- S ,or a divalent hydrocarbon `
radical having from 1 to 18 carbon atoms inclusive, with the provlsions tha-t when R is - O - , R' is other than O ; when R' is - O - , R is other than - O - ;
when G is II, C' is V, and when G' is IV, G is III.

.

... . .. , ........... . __~_, _ ~3 ~ 2~ ~ ;

Polyarylene polyethers of this type exhibit excellent physical properties as well as excellent thermal oxidative and chemical stability. Commercia]. poly(aryl polyethers) are ~ available under the trade ~R~ ARYLON T ~ Polyaryl ethers~
having a melt temperature of between 280C and 310C.
Another group of useful engineering thermoplastic resins include aromatic poly(sulphones) comprising re~
peating units of the formula:

Ar S0 in which Ar is a bivalent aromatic radical and may vary ~ ~ ;
from unit to unit in the polymer chain (so as to I'orm co~
polymers o~ various kinds~. Thermoplastic poly(sulphones) :
generally have at least some units of the structure:

.
in which Z is oxygen or sulphur or the residue of an aromatic diol, such as a 4,4'-bisphenol. One example of such a poly(sulphone) has repeating units of the ~ormula:
~3----/~SO2 2~

-27- :

another has repeating uni.ts Or the formula:

~ s~o2- ~

and others have repeating units of the formula:

~3 S2 ~ - ~ ~ ~/ 3 - O - ;~
3 ~ :~
or copolymeri.zed units ;.n various proportions of the ~ormula:

~ 2 and O
' ~ ' The thermoplastic poly(sulphones? may also have repeating units having the formula:

~,/~ ~ - ~ S2 Poly(ether sulphones) having repeating units Or the following structure:

3~

t/~3 ~3 1 n and poly(ether sulphones) having repeating units of the following structure:
~3so2 ~ c~l3~-L
C~13 ~ ~ `
_ n ~ ~;
:~ ' are also useful as engineering thermoplast:ic resLn~
The polycarbonates which may be present in the com-positions accordlng to the invention are of the general formulae:

o --~Ar- A- Ar- O - C - 0~
n and - ~Ar --O - C -0~

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.

32~

The preparation of the polycarbonates i5 well known.
A preferred method of preparation is based on the reaction carried out by dissolving the dihydroxy component in a base, such as pyridine and bubbling phosgene into the stirred solution at the desired rate. Tertiary amines may be used to catalyze 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 of phosgene and di~
hydroxy reactants, however, thé molar ratios can be varied dependent upon the reaction conditions.
In the formulae I and II mentioned, Ar and A are, preferably, p-phenylene and isopropylidene~ respectively.
This polycarbonate is prepared by ~el~ct;ng para,para'iso-propylidenediphenol with phosgene and is sold under the trade mark LEXAN ~ and under the trade mark MERLON
This commercial polycarbonate ha~ a molecular weight o~
around 18,000, and a melt temperature o~ over 230C.
Other polycarbonates may be prepared by reactin~ other dihydroxy compounds~ or mixtures Or 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 Or the structure may be replaced by siloxane linkage.

;23~

By polyamide is meant a condensat:ion product which contains recurring aromatic and/or aliphatic amide groups as intc~ral parts of the main polymer chain, such products being known generi.cally as "nylonsl'. 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-izing 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.
~ he term "substantially equimolecular proportions"
(of the diamine and of the dicarboxylic acid) is used to cover both strict equimolecular proportions and the slight departu~e~ r^~rom which are involved in conventional , , ~ :, . .. ... . _ .". ~ . _ . _ .. __, _. . . ....

~ 3 ~

techniques for stabili~ing the viscosity of the resultant polyamides.
As examp]es Or the said mono-aminomonocarboxylic acids or lactams thereof there may be mentioned those compounds containing from 2 to 16 carbon atoms between the amino and carboxylic acid groups, said carbon atoms forming a ring with the CO.NH - 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 Or the general f`ormula ~I~N(CH2)nNH2, ~herein n is an integer of from 2 to 16, such as trimethylenediamine, tetramethylene-diamine, pentamethylenediamine, octamethylenediamine, decamethylenediamine, dodecamethylenediamine, hexadeca-methylenediamine, and especially hexamethylenediamine~
C-alkylated diamines, e.g~, 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-diamine~ 4,4'-diaminodiphenyl sulphone, 4,4'wdiaminodi phenyl ether and 4,ll'-diaminodiphenyl sulphone, 4,4'-di-aminodlphenyl ether and 4,ll'-diaminodiphenylmethane; and cycloaliphatic diamines, for example diaminodicyclohexyl-methane.

I'he said dicarboxylic acids may be aromatic, for example isophthalic and terephthalic acids. Preferred dicarboxylic acids are of the rormula HOOC.Y.COOH, wherein Y represents a divalent aliphatic radical containing at least 2 carbon atoms~ and examples of such acids are sebacic acid, octadecanedi~c acid~
suberic acid, azelaic acid, undecanedioic acid, glutaric -~
acid, pimelic acid, and especially adipic acid. Oxalic acid is also a preferred acid.
Specirically the :rollowing polyamides may be in-corporated in the thermoplastic polymer blends of the invention:
polyhexamethylene adi.pamide (nylon 6:6) -polypyrrolidone (nylon 4) polycaprolactam (nylon 6) polyheptolactam (nylon 7) ~olycapryllactam (nylon 8) polynonanolactam (nylon 9) polyundecanolactam (nylon 11) polydodecanolactam (nylon 12) polyhexamethylene azelaiamide (nylon 6:9) polyhexamethylene sebacamide (nylon 6:10) polyhexamethylene i.sophthalamide (nylon 6:iP) polymetaxyly].ene~ipamide (nylon MXD:6) polyamide of hexamethylene diamine and n-dodecanedioic acid (nylon 6:12) 3~

polyamide of dodecamethylenediamine and n dodecanedioic aci.d (nylon 12:12).
Nylon copolymers may also be used, for example co-polymers of the.following:
hexamethylene adlpamide/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 trlmethyl-6:2/6:2) hexamethylene adipamide/he~amethylene-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.
Pre.ferred nylons include nylon 6~6/6, 11, 12, 6/3 and 6/12.
~he number average molecular weights of the polyamides may be above 10,000.

- 3 L~ 3~

Polyurethanes, o-therwise 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 polyols, such as~ polyoxyethylene glycol, polyoxypropylene glycol, hydroxy--terminated polyesters, poly-oxyethylene-oxypropylene glycols are suitable.
These thermoplastic polyurethanes are available under ~ ,~C~r~ ~ ~
10 ~L~ the trade-~ Q-THANE~ and under the trade ~ffle-PELLETHANE ~ -CPR.
Another group of useful engineering thermoplastics in~ -clude those halogenated thermop]astics having an essentially crystalline structure and a melt point in excess of 120C.
15 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 20 fully fluorinated polymers of the basic chemical formula 2-~ - which contain 76% by weight fluorine.
` These polymers are highly crystalline and have a crystalline . . . ~
,,. ~
~ ' ~ .

rnelting point of over 300C. Commercial P'l'FE is available ~ 0,~
urlder the traf1~ ~4 Tl~r~'L,ON ~ and undc~r the trade ~
li'LIJON ~ . Polych10rotr:irluoroethylene (PC'I'1~E) and poly-: bromotrifluoroethylene (Pl3T~E) are also available in high molecular welght~ and can be employed in the presenl; in-verlt ion .
EGpecially preferred halogenated polymers are homo-pol.ymers and copolymers of vinylidene fluoride. Poly (vlnylidene fluori.de) homo~olymers are the ~arti.ally :LO I'luor:irlated polymers ol` the chc~nlical formula -~--C~12--Cl~2-~.
These polylrler, are tou~rh :L.i.rlear E)o1ymers w.ith a cry<ta:l:l;.no melting point at 170C. Commerc:ial homopolymer is ava.illt)].e ; under the trade ~K~ KYNAI~ ~ The tc~rm '~poly(v:i.nyliderle I'luori.de)" as used here.in rcrer not nnly to the norma].1.y so].id homopolymers of vinylidene fluoride, but also to the normally soli.d copolymers of' v;.nylidene fluoride containin~
at least 50 mol.% of polymerized vlnylidene rluori~e unit~, preferably at least 70 mol.% vinylidene rluoride and more pref'erably at least 90 mol.%. Suitable comonomers are halogenated olefins containing up to 4 carbon atoms, for examp].e, sym. dichlorodifluoroethylene, vinyl fluoridej ~ .
vinyl chloride, viny].idene chloride, perfluoropropene,per-rluorobutadiene, chlorotrirluoroethylene, trichloroethylene and tetrafluoroethylene.
Another useful group Or halogenated thermoplastics include homopolymers and copolymers derived from vinylidene chloride~ Crystalline vi.nylidene chloride copolymers are 23~

: -~6-especi.ally preferred. The normally crystal:l.ine vinylidene chlorlde copolymers that are useful in the present in-vention ar~ those contairling at least 70% ~y weight Or vinylidene chloride together with 30% or less of a co-polymerizable monoethylenic monomer. Exemplary of such monomers are vinyl chlor;de7 v:inyl aceta.te, vinyl propi.onate, acry:lonitril(;, alkyl and aralkyl acrylates havirlg alky] and aralkyl groups Or up to about 8 carbon .
atoms, acryl.;.c ~lci(~, acrylam;.d(?, vinyl alkyl ethers, vlnyl alkyl ketono.;, acrol.ein, a:l.l.yl ethers arld others, butadi.ene and chloropror)ene~ Known tcrrlary compos.itiorls also may be employed advarltageous.Ly. ]~epr~;orltntive Or such polymers are those composed of` at least 70% by wei~ht oI v;.nylidene chlori.de wi.t;h the remaill(ler made up oI, for example, acrolei.n and vinyl chloride 3 acrylic acid an(l acryloni.trile, alkyl acrylates and alkyl methacrylates, ~:
acrylonitri.le and butadielle, acrylonitril~ and i.taconic ~: -acid, acrylonitrile and vinyl acetate, vinyl propionate or vinyl chloride~ allyl esters or ethers and vinyl ;;
; 20 chloride, butadlene and vinyl acetate, vinyl propionate, :
~ or vinyl chloride and vinyl ethers and vinyl chloride.
; Quaternary polymers of sirnilar monomeric composition will also be known. Particularly useful for the purposes the present invention are copolymers o~ rrom 70 to 95% by wei~ht vinylidene chloride with the balance being vinyl chloride. ',uch copolymers may conta;.n conventional amounts 3~3 and types of plasticizers, stabilizers, nucleators and extrusion aids. Further~ blends of two or more o~ such normally crystalline vinylidene chloride polymers may be used as well as blends comprising such normally crystalline polymers in combinatiorl 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,beta-; olerinically unsaturated mononitrile content Or 50% by weight or greater. These nitrile resins may be homopolymers, copolymers, grafts Or copolymers onto a rubbery substrate, or blends of homopo]ymers and/or copolymers.
The alpha~beta-olefinically unsaturated mononitriles encompassed herein have the structure Cll2 C CN
R
where R is hydro~en, an alkyl group having from 1 to 4 carbon atoms~ or a halogen. Such compounds include acrylo-nitrile, alpha~bromoacrylonitrile, alpha-~luoroacrylo-ni-trile, methacrylonitrile and ethacrylonitrile. The most preferred olefinically unsaturated nitriles are acrylo-nitrile and methacrylonitrile and mixtures thereo~.
These nitrile resins may be divided into several classes on the basis of cornplexity. The simplest molecular .. .. ,~ . ......... .... . . .. ....... .... .. .

3~

structure is a random copolymerg 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 o~ polystyreneS or Or 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-olerins o~ from 2 to 8 carbon atoms 3 e.g. ethylene, propylene, iso-butylene, butene-1~ pentene-1 and their halogen and , aliphatic substituted derivatives as represented by vinyl chloride and vinylidcne chloride; monovinylidene aro~atic hydrocarbon monomers o~ the general formula~

~12C~C,~
R~

wherein R1 is hydrogen chlorine or methyl and R2 is an aromatic radical of 6 to 10 carbon atoms which may also contain substituents~ such as halogen and alkyl groups attached to the aromatic nucleus, e.g., styrene, alpha methyl styrene, vinyl toluene, alpha-chlorostyrene, ortho-chlorostyrene, para-chlorostyrene, meta-chlorostyrene, ortho-methyl styrene, para-methyl styrene, ethyl styrene 5 ~82~3~
.

~ 9 isopropyl styrene, dlchlorostyrene and vinyl naphthalene.
Especially preferred comonomers are isobutylene and styrene.
Another group of comonomers are vinyl ester monomers of the general formula:

H
R3C=C
O
C=O

wherein R~ i5 se]ected from the group comprising hydrogen, alkyl groups of rrom 1 to 10 carbon atoms, aryl groups Or from 6 to 10 carbon atoms lncluding the carbon atoms in ring-substituted alkyl substituents; e.g.3 vinyl formate, vinyl acetate, vinyl proplonate and vinyl benzoate.
10Similar to the foregoing and also useful are the vinyl ether monomers of the general formula:
H2C-C~I 0 - R4 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 15aliphatic radical may be hydrocarbon or oxygen-containing, ~-e.g.3 an aliphatic radical with ether linkages, and may also contain other substituents, such as halogen and carbonyl. Examples of these monomeric vinyl ethers include vinyl methyl ether, vinyl ethyl ether3 vinyl n-butyl ether, vinyl 2-chloroethyl ether, vinyl phenyl ether, vinyl iso-..... , _ . . , .. , .. . .. . _ .. .. _ .. .... .

~: .

~8~8 - 1l o -butyl ether, vinyl cyclohexyl ether, p-butyl cyclohexyl ether, vinyl ether or p-chlorophenyl glycol.
Other comonomers are those comonomers which contain a mono- or dinitrile functlon. Examples of these include methylene glutaronitrile, (2,4-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 preIerred the esters having the structure~

CH2 = C COOR2 wherein Rl is hydrogen, an alkyl group having from 1 to 4 carbon atoms, or a halogen and R2 is an alkyl group hav;ng from 1 to 2 carbon atoms. Compounds Or 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.
Anather class of nitrile resins are the graft co-polymers which have a polymeric backbone on which branchesof another polymeric chain are attached or grafted.
Generally the backbone is preformed in a separate reaction.
Polyacrylonitrile rnay be grafted with chains of styrene, ~82313 - Ll 1 -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 oE 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 which 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 copolymer of acrylonitrile and the same comonomer. The acrylonitrile~
based thermoplastics are frequently polymer blends of a grafted polymer and an ungrafted homopolymer.
G'ommercial examples Or nitrile resins include BARE~
210 resin, an acrylonitrile-based high nitrile resin con-taining over 65% nitrile, and LOPAC ~ resin containing over 70% ni-trile~ three-fourths of it derived rrom metha-cry].onitrile.
In order to better match the viscosity characteristics ~ -of the thermoplastic engineering resin, the polyacetal and the block copolymer, it is sometimes useful to first : blend the dissimilar thermoplast;c engineering resin with a viscosity.modi~i.er before blending the resulting mixture with the pol.yacetal and block copolymer. Suitable viscosity modifiers have a relatively high viscosity, a melt temper-10 ature of over 230 C~ and possess a viscosity that is not very sensitive to chan~es in temperature. Examples o~ suit~
able viscosity modifiers include poly(2,6-dimethyl-1,4-phenylene)oxide and blends of poly(2,6-dimethyl-1,ll-phenyl-:~ ene)oxide with po]ystyrene.
The poly(phenylene oxides) inclucled as possible viscosity modifiers may be presented by the following ~ ~.
formula:
R

~r~t . R'1 m wherein R1 is a monovalent substituent selected from the group consisting Or hydrogen, hydrocarbon radicals rree of a tertiary alpha-carbon atom, halohydrocarbon radicals having at least two carbon atoms between the halogen atom and phenol nucleus and being free of a tertiary alpha-carbon atom, hydrocarbonoxy radicals free of aliphaticg tertiary alpha-carbon atoms 9 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., from 50 to 800 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-methyl 1,4-phenylene)oxide.
~5 Cornmercially, the poly(phenylene ~xide) is available as a blend with styrene resinO These b:Lends typically comprise between 25 and 50% by weight polystyrene unitsJ
and are available under the _ _ B ~or~ ,~
trade ~ NORYL ~f thermopla,stic resln. The preferred molecular weight when employing a poly(phenylene oxide)/
polystyrene blend is between 10,000 and 50,000, preferably around 30,000.
The amount of viscosity modifier employed depends primarily upon the diff'erence between the viscosities of the block copolymer and the engineering thermoplastic resin at the temperature Tp. The amounts may ran~e from O to 100 3~

parts by weight viscosity modifier per 100 parts by weight engineering thermoplastic resin, prefer-ably from 10 to 50 parts by weight per 100 parts of engineerin~ 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 method, an lnterlocking 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 components~ and the remaining polymer structure (comprising the thermoplastic engineer-~; ing resin and polyacetal3 still has the shape and con-tinuity of the moulded or extruded object and i~ inkact structurally without any crumbling or delamination, and , the refluxing solvent carries no insoluble particulate matter. If these criteria are fulfilled~ then both the unextracted and extr~cted phases ~e interlocking and continuous. The unextracted phase must be continuous - 20 because it is geometrically and mechanically intact.
The extracted phase must have been continuous before extraction, since quantitative extraction o~ a dispersed phase from an insoluble matrix is highly unlikely.
Finally, interlocking networks must be present in order to have simultaneous continuous phases. ~lso~ confirmation of the continuity of the unextracted phase may be ~ 5~

conf'irmed by rn:icroscopic e~amination. 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 isotropically 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 networkg 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 ~15 the relative proportions of the various polymers in ~he blend can be varied over a wide range. The relative proportions of the polymers are present;ed below in parts by weight (the total blend comprising 'L00 parts):

Parts by Preferred weight parts by ;20 weight Dissimilar engineering thermoplastic resin 5 to 4~ 10 to 35 Block copolymer 4 to 40 8 to 20 The polyacetal is present in an amount greater than the amount of the dissimilar engineering thermoplastic, i.e., the weight ratio of polyacetal to dissimilar engineering thermoplastic is greater than 1:1. Accordingly, the amount of polyacetal may vary from 30 parts by weight ;1 to 91 parts by weight, preferably from 48 to 70 parts by weight. Note that the minimum amount of block copolymer necessary to achieve these blends may vary with the particular engineering thermoplastic.
; The dissimilar engineering thermoplastic resin, poly~
acetal and the block copolymer may be blended in any manner ~lO that produces the interlocking network. ~or example, the resin, polyacetal 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 useful 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 mechanical shear and thermaI
energy to ensure that interlocking of the various .: ~\ , ~ . .

~8;~3~

networks is achieved. Intimate mixing is typically achieved by employing high shear extrusion compounding machines, such as twin screw compoundlng extruders and `- thermoplastic extruders having at least a 20:1 L/D ratio and a compression ratio of 3 or 4:1.
;; The mixing or processing temperature (~p) 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 addition, as explained more fully hereinaf`ter, the processing tempera-ture may also be chosen so as to permit the isoviscous mixing of ~ ;
the polymers. The mixing or processing temperature may be between 150C and 400C, preferably between 230C and 300C.
Another parameter that is important in melt blending~
to ensure the forrnation of interlocking networks is matching the viscosities of the block copolymer, polyacetal and the dissimilar engineering thermoplastic resin (isoviscous mixing) at the temperature and shear stress of the mixing process. The better the interdispersion Or the engineering resin and polyacetal in the block copolymer network, the better the chance for f`ormation of co continuous inter-locking networks on subsequent cooling. Therefore~ it hasbeen found that when the block copolymer has a viscosity ? ~~ ~----~~---------- -----n poise at temperature Tp and shear rate Or 109 s 1, it is preferred that the engineering thermoplastic resin and/or the ~)ol,yace~al have such a viscosity at the temper-ature Tp and a shear rate of 100 s that the ratio Or the viscosity of the block copolymer divided by the ~iscosity Or the engineering thermoplastic and/or polyacetal be between 0.2 and 4.0, preferably between 0.8 and 1.2. ' , Accordingly, as used hereing isoviscous mixing means that the viscosity of the block copolymer divided by the viscosity o~ the other polymer or polymer blend at the temperature Tp and a shear rate Or 100 s 1 is between 0.2 and 4Ø It should also be noted that within an extruder, there is,awide distribution o~ shear rates.
Therefore~ isoviscous mixing can occur even though the viscosity curves o~ two polymers difrer at some of the shear rates.
In some cases, the order Or mixing the polymers is critical. Accordingly, one ma~ choose to mix the block copolymer with the polyacetal ,or other polymer ~irst, and 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 Or mixing that can be employed, resulting in the multi-component blends Or the preC;e~t invention. It is also clear that the order of mixing can be employed in order to better match the relative viscosities Or the various polymers~

3l~

ll9 The block copolymer or block copolymer blend may be selected to essentially match the viscosity of the engineering thermoplastic resin and/or po1yacetal.
Optionally~ the block copolymer may be mixed with a rubber compounding oil or supplemental resin as described hereinafter to change the viscosity charac-teristics of the block copolymer.
The particular physical properties o~ the block copolymers are important in forming co-continuous inter-locking networks. Specif'ically, the most preferred blockcopolymers when unblended do not melt in the ordinary sense with increasing temperature, since the viscosity of these polymers is highly non-Newton:ian and tends to increase without limit as zero shear stress is approached~
Further, the viscosity of these block copolymers is also -~
relatlvely insensitive to temperatureO This rheological behaviour and inherent thermal stability Or the ~lock co-polymer ehhances its ability to retain its network (domain) structure in the melt so that when the various blends are ~ade,interlocking and continuous networks are formed.
The viscosity behaviour of the engineering thermoplastic resins, an(l ~)olyaccta]s on the other hand, is more sensitive to temperature than that of the block copolymers. Ac-cordingly, it is often possible to select a processingternperature Tp at which the viscosities of the block copoly~er and dissimilar engineering resin and/or poly-acetal fall within the required range necessary to form interlocking networks. Optionally, a viscosity modi~ier, as hereinabove described, may ~irst be blended with the engineering thermoplastic resin or po~yacetal to achieve the necessary viscosity matching.
The blend of partially hydrogenated block copolymer, pdlyacetal and dissimilar engineering thermoplastic resin may be compounded with an extending oil ordinarily used in the processing of rubber~and plastics. Especially pre~erred are the types Or oil that are compatible with the elastomeric polymer blocks Or 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 prererred. The oils preferably have an initial boiling point above 260C.
~he amount of oil employed may vary ~rom O to 100 phr (phr = parts by weight per hundred parts by weight of block copolymer), pre~erably from 5 to 30 phr.
The blend o~ partially hydrogenated block copolymer, polya(~tal and dissimllar 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~

~ 3 -5~-Suitable end~block plasticizing resins include coumarone-indene resins, vinyl toluene-alpha-methylstyrene co-polymers~ polyindene resins and low molecular weight polystyrene resins.
The amount of additional resin may vary from O to 100 phr, preferably from 5 to 25 phr.
Further the composition may contain other polymers, fillers, reinforcements~ anti-oxidants~ stabilizers, fire retardants, anti-blocking agents and other rubber and plastic compounding ingredients.
Examples Or 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 o~
the polymer. Most of these reinforcing materials are in-organic or organic products Or high molecular weight.
Examples of reinrorcements are glass fibres, asbestos, boron fibres, carbon and graphite fibres, whiskersg quartz and silica fibres, ceramic fibres, metal fibres, natural organic fibres, and synthetic organic fibres. Especially preferred are reinforced polymer blends containing 2 to 80 per cent by weight Or glass fibres, based on the total weight Or the resultirlg rcirllorced blend.
The polymer blends of the invention can be employed as meta] replacemerlts and in those areas where high perf`ormance is necessary.

3~

Irl the illustrative Examples given be1ow, various polymer blends were prepared by mixing the polymers in a 3.125 cm Sterling Extruder having a Kenics Nozzle. The extruder has a 2ll:1 L,/D ratio and a 3.8:1 compression ratio screw.
The various materials employed in the blends are listed below:
1) Bloc~ copolymer - a selectively hydrogenated block copolymer according to the invention having a structure S-EB-S.
o B 2) Oil TUFFLO 6056 rubber extending oil.
3) Nylon 6 - PLASKON ~ 8207 polyamide.
4) Nylon 6-12 - ZYTEL ~ 158 polyamid~.
5) Polypropylene - an essentially isotactic poly-propylene having a melt flow index of 5 (230C/2.16 kg).
6) Poly(butylene terephthalate~ PBT") - ~ALOX
310 resin.
7) Polycarbonate - MERLON ~ M-40 polycarbonate.
8~ Poly(ether sulphone) - 200 P.

9) Polyurethane - PELLETHANE ~ CPR.

10) Polyacetal - DELRIN ~ 500.

11) Poly(acrylonitrile~co-styrene) - BAREX ~ 210.

12) Fluoropolymer - TEFZEL ~ 200 poly(vinylidene fluoride) copolymer.
In all blends containing an oil component, the block co-polymer and oil were premixed prior to the addition of the other polymers.

Illustrative x mple I
Various polymer blends were prepare-d according to the invention. A blend of two block copolymers of a higher and lower molecular weight was employed in some polymer blends in order to better match the viscosity with the polyacetal 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 115 containing just the poly-acetal and Nylon 6 suffered from die swell, surging, and melt fracture. In contrast, in each blend containing a block copolymer, the polymer blend was easily mixed, and the extrudate was homogeneous in appearance. Further, in each blend containing a block copolymer, the resulting polyblend had the desired continuous, interlocking net-works as established by the criteria hereinabove described.
~he compositions and test results are presented below ~- 20 in Tables 1 and 2. ~he compositions are listed in percent by weight.

- 51~ -.. . .. . .. ... . .. .. . .. . . . .. .... ... .

l O r~ ~
~-1 Lr~ ~1 O L~ Lr~
~t 1~ ~ L~
., O ~ ~
r~
L~

O L~ L~
0~
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~ ~I L~\

1- O r~
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r~l ~ ~ ~ ~ .
~1 ~ O Lr~ L~
Lr\

c) a~ ~ a) rl o ~ u~ ~, ~ ~ ~ ~ O a Q
. a) oa~ ~d ~~ O
O
Z o ~ Q ~ ~) :5 ~ ~1 ~D C) ~1 ~I c) ,n O
5: Q~ ~ Q~ 1 ~ O ~
a) o ~ o ~~1 a~ ~ ~ ~ o ~1 r~ rl ~ OO ~) O ~ O C) m m o ~ P~ ~ z ~
_ .. ............. . _._ ___ __ 2~

__ ~ ~ ~ ~

r.-- Lr~ L~ : :

Lr~ O O ~ ~:
L~ L~
~1 N r.-o~ O O
O L(~ L~

O O
L~ Lr~
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O
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.
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c) a) ~ ~ rl O
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. a) o a~ ~ ~ ~ o ~ a~
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a) o ~ o ~1 ~ a) ~ ~ ~ o C~ O O ~ O ~ O V
---- m ~ P~

..

O ~(~ G~L( \
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O O O O O(~I ~1~1 O O O O O O OO
O O O O O O ~~\
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o~ l n 0~1 0 C~
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. . .. . . ..
O O O O O O OO
O O O O O O OO
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J ~ ~Lt~ ~ Lr~ ~D
O O O O OO
O O ~l O OO
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~1 . . .. . . .

~1 ..... .. .
O O O O O O O O
O O ~ O OL('\ O O
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~1 Lr~ ~ ~D ~ ~ G~
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a) o ~ ~ cot--C-- O G~G~
Z; ~1 ~1 ~1 m -57~ 38 ~

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r~ tL~
Lt~ Lt~ t~l t~l CO ~1C~) ~ ''I t~
Lt~ o ~ c~ co S~ ~0 O O O O O ~ ~ ~I tl~ tl) tn co oo~oLt~ O ~ ~ ~ F'l tL
~O I ~o ~Lt~Lt~1--t~ L~ O
O ~1 0 0 0 ~1 ~I t~
tl) r~
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"'I ' ot~JLt~Cl ) CO ~ ~ t`~ I ' I . . . . . . . . S I O tt:
t\l O O O ~ ~ Lt'~ tl~
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. . . . . . . ~1 -~ rn tn t~ tn ~n tl~ p 5~ p 5~
X O ~ r~ rr~l r~l r-! r-/
O C~ ~r~
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l~ Xtn ,~
tn tl) P r-l M~ r~ ~ r~
t ~ ~ C~~1 ~1 ~t ~ t~,~ ~ S~ tl~ tl) tL) t~ tl~
N ¦C~ ~ ~ ~ ~ ~ ~1 0r-l triS~
t~ tL~ t~ ~
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CJ~ Ot\~ ~ C~ O
r,~1 l~0 C~ ~0 0Lt~ 1~ 0 ~
o~ I . . . . . . . C~ 0~1 C~l 1~ ~ Lt~ ~O, c) Lt~ ~ ~Lt~Lt~ ~ Lt~ ~ ~ ~ ~1 ~1 ~1 ~1 ~1 ~1 CU O I r~ t~l C~ ~ t~l ~D 0 '~1~ ~ ~ o o 0 L~ ~t~J ~ ~t~lc~l CU t~l ~ ~ Lt~
~Itl~ O Lt~
~3 ~ O
r~
O r~Lf`\ O OLt~ O O Lt`\ O X
r-l O ~ ~1 ~ ~rl X
m 0~, ~ tn rl eS2. c~ tnQ. tn r~ Lt.~
~0 ^ ~ O O
tL) ~ ,~ rl tL) ~ ~ r~ ~ tQ
S: t~i S~ r~ ~ bO X
O tl~ ,~ r~ _ ~rl ~rl ~rl S~ ~ ~ ~ o rR rn tn S~ ~ S~ ~ O ~ ~rl r~
tl) t~ rl ~ O tn tl ~ ~ C~ ~ tD tn ~ ~3 tR
r~ r~ l . r~ r-l r-1 ~ ~
o ~ m o o rl ~ ,~, ~ tL~ E3 r-l El ; ~1 ~ C~ tn r, ~i r~ t~ ~rl ~ ~r~
_ ,~ C) tl~ S~ X ~:1 X
r' . tii t O tL) ~rltl) t~i O t i tL) O N 1~\ t.~ ~- 0 0 1 r~ Z; ~J ~1 0 ~ ~ O C~ O~
m ~ ~ ~ ,~ ~I N r\ ~ Lt~ ~O ~ OC) -5~-~ 2~ ~

The results of the above blends indicate the presence of unobvious properties for the blends. For example, by examining -the ratio of the relative increase in Izod impact strength (at 23C) over the relative decrease in heat distortion temperature for polymer blends as the percentage of block copolymers is increased from 0% to 15% at a fixed 1:3 ratio of polyacetal to dissimilar engineering thermoplastic, it can be seen that much larger than expected values are obtained. One skilled in the art would typically expect this value to be positive and less than 1. However, for blends containing PBT and polycarbonate the ratios are 13 and 28 respectively.

Claims (32)

C L A I M S

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) an acetal resin having a generally crystalline structure and a melting point over 120°C, (c) 5 to 48 parts by weight of at least one dissimilar engineering thermoplastic resin being selected from the group consisting of polyamides, polyolefins, thermoplastic polyesters, poly(aryl ethers), poly-(aryl sulphones), polycarbonates, thermoplastic polyurethanes, halogenated thermoplastics, and nitrile resins, in which the weight ratio of the acetal resin to the dis-similar 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 acetal resin is a polyacetal copolymer.

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 dissimilar engineering thermoplastic resin is a thermoplastic polyester having a melting point in excess of 120°C.

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

10. A composition as claimed in claim 9, 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.

11. A composition as claimed in claim 1, in which the engineering thermoplastic resin is a polycarbonate having the general formula:

I
or 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.

12. 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.

13. 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.

14. 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.

15. A composition as claimed in claim 14, 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.

16. 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.

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

18. A composition as claimed in claim 17, in which the composition contains an extending oil in an amount of from 5 to 30 phr.

19. 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.

20. A composition as claimed in claim 19, in which the composition contains a flow-promoting resin as additional resin in an amount of from 5 to 25 phr.

21. A composition as claimed in claim 19 or 20, in which the composition contains an additional resin selected from the group consisting of an alpha-methylstyrene resin, coumarone-indene resins, vinyl toluene-alpha-methyl-styrene copolymers, polyindene resins and low molecular weight polystyrene resins.

22. 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) an acetal resin having a generally crystalline structure and a melting point over 120°C, and (c) 5 to 48 parts by weight of at least one dissimilar engineering thermoplastic resin being selected from the group consisting of polyamides, polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones), polycarbonates, thermoplastic polyurethanes, halogenated thermoplastics and nitrile resins, in which the weight ratio of the acetal resin 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.

23. A process as claimed in claim 22, characterized in that the polymers are mixed at a processing temperature Tp of between 230°C and 300°C.

24. A process as claimed in claim 22 or 23, 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.

25. A process as claimed in claim 22 or 23, characterized in that the polymers are mixed as granules and/or powder in a device which provides shear.

26. A process as claimed in claim 22, characterized in that the ratio of the viscosity of the block copolymer divided by the viscosity of the polyacetal, the dissimilar engineering thermoplastic resin or the mixture of the polyacetal 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.

27. A process as claimed in claim 26, characterized in that the viscosity ratio of the viscosity of the block copolymer divided by the viscosity of the polyacetal, the dissimilar engineering thermoplastic resin or the mixture of the polyacetal and the dissimilar engineering thermo-plastic resin is between 0.8 and 1.2 at the processing temperature Tp and a shear rate of 100 s-1.

28. A process as claimed in claim 22, characterized in that the dissimilar thermoplastic resin is first blended with a viscosity modifier before blending with the polyacetal and the block copolymer.

29. A process as claimed in claim 22, characterized in that as viscosity modifier poly(2,6-di-methyl-1,4-phenylene)oxide, or a blend of poly(2,6-dimethyl-1,4-phenylene)oxide with polystyrene is used.

30. A process as claimed in claim 28, characterized in that the viscosity modifier is used in an amount of from 0 to 100 parts by weight per 100 parts by weight of engineering thermoplastic resin.

31. A process as claimed in claim 30, 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.

32. A process as claimed in claim 22, 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.