CA2032370A1

CA2032370A1 - Elastomer-modified polyarylene sulphide moulding compounds

Info

Publication number: CA2032370A1
Application number: CA 2032370
Authority: CA
Inventors: Karl-Heinz Kohler; Hartmuth Buding; Herbert Eichenauer; Joachim Thormer
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1989-12-16
Filing date: 1990-12-14
Publication date: 1991-06-17
Also published as: EP0435024A2; JPH03258857A; EP0435024A3; DE3941564A1

Abstract

Elastomer-Modified Polyarylene Sulphide Moulding Compounds A B S T R A C T

This invention relates to thermoplastic moulding compounds of polyarylene sulphides (PAS), preferably compounds of polyphenylene sulphides (PPS), and uncross-linked, hydrogenated nitrile rubbers.

LeA 27 153

Description

2~ 3'7~3 ~lastomer-Modified Polvar~lene Sulphide Mouldinq Compounds This invention relates to thermoplastic moulding compounds of polyarylene sulphides (PAS), preferably compounds of polyphenylene sulphides (PPS~ and uncross-linked, hydrogenated nitrile rubbers.

Partially crystalline polyarylene sulphides, e.g. poly-phenylene sulphide, have properties which are disadvantageous for certain uses, e.g. low stretchability and low toughness.

The applications in question include, for example, the construction of moulded parts containing spring catches or moulded parts which require ~O ~e after-treated for the form3ti~n of beadings on the edges or the construction of cable sheaths for cables with small radii of curvature. For these uses, in which the moulded parts may be subjected to sin~le or repeated considerable bending or impact stresses, the materials are required to retain the advantageous properties of poly-arylene sulphides.

Polyarylenç sulphides of low crystallinity, e.g. polyarylene sulphides which are predominantly amorphous such as poly-LeA 27 153 ~0~.370 diphenyl sulphone sulphide or copolyphenylene sulphidescontaining high proportions of m-phenylene sulphide units, show these defects in properties only to a slight extent but these polymers hardly have the typical properties which are due to the crystallinity of the polymer.

It is known that partially crystalline thermoplasts, including polyarylene sulphides, may be modified by the introduction of rubbers to improve their toughness without significantly altering their other properties. The rubbers used may be graft rubbers based e.g. on diene or acrylate rubber (e.g. EP-A 247 412, DE-A 3 616 131) or uncross-linked, non-particulate rubbers based on EP, EPDM
or acrylate polymers ~e.g. EP-A 142 825) or styrene-butadiene rubhers (~P-A 259 188).

The above mentioned rubbers differ greatly in their capacity to improve the toughness of the compound and in some cases cause considerable defects in certain properties, e.g.
thermal stability, oxidation resistance and chemical resistance.

It has now heen found that polyarylene sulphides (PAS), especially polyphenylene sulphide (PPS), may be modified hy means of hydrogenated nitrile ruhhers so that the polymer mixtures obtained are substantially improved in their toughness and at the same time have high temperature resistance and dimensional stability under heat as well as high chemical resistance.

The present invention thus relates to polyarylene sulphide moulding compounds, preferably polyphenylene sulphide moulding compounds, containing:

A) from 30 to 99 5 parts by weight of polyarylene sulphide, preferably polyphenylene sulphide, LeA 27 153 B) from 0-5 to 70 parts by weight, based on th~ ~ ~a~ 7 weight of the moulding compound of (A~B), of hydrogenated nitrile rubbers,and optionally C) from 0 to 60 parts by weight, based on the total weight of the moulding compound of (AtB~C), of fillers and reinforcing materials.

Polyarylene sulphides suitable for the purpose of this invention are known (e.g. US-A 3 354 129 and EP-A 171 021) and commercially available. The polyarylene sulphides may be linear, branched or cross-linked.

The degree of hranching or cross-linking may be adjusted by using multifunctional monomers for the synthesis of the polyarylene sulphide or hy suitable after-treatments of the predominantly linear polyarylene sulphide.

The following are examples of suitable polyarylene sulphides for component A: polyphenylene sulphides, poly(alkylene-phenylene)sulphides, polydiphenylene sulphides, polytetra-phenylene sulphides, polynaphthylene sulphides, polyketone sulphides, polys-1lphone sulphides, polyarylene sulphides 2(J containing heterocyclic monomer units and co-polyarylene sulphides. Partially cr-ystalline polyarylene sulphides are preferred. These are recognizahle by their melting and crystallization temperatures in the ~SC. Poly-1,4-phenylene sulphide is particularly preferred.

In reinforced compounds, the melt viscosities of the poly-arylene sulphides used are from 20 to 170 Pa~s, preferably frorn 35 to 80 Pa.s, and in unreinforced compounds the melt viscosities are from 60 to 300 Pa.s, preferably from 80 to 200 Pa.s, determined in each case at 320C, 103(1/s).

The melt viscosities are determined in a conventional commercial high pressure capillary viscosimeter at various LeA 27 153 - X~)3~3~
shearing velocities (1/s) and at a temperature of the melt of 320C. The ~m value (in Pa.s) at 10' (1/s) is given as reference value from the viscosity function o~tained.

Components B in the context of this invention are hydrogenated nitrile rubbers, i.e. copolymers of unsaturated nitriles and conjugated dienes, in which the degree of hydrogenation of the C=~ double honds is greater than 50%, preferably greater than 70%, most preferahly greater than ~0%, especially greater than 98%, and the unsaturated nitrile content is from 10 to 60% by weight, preferably from 15 to 50% ~y weight, in particular from 18 to 48%
by weight.

The hydrogenated copolymers are gel free and soluble in ketones such as acetone or butanone, in ethers such as tetra-hydrofuran or dioxane and in chlorinated hydrocarbons suchas dichloromethane or chlorobenzene. "Selective hydrogenation"
in the context of this invention means the hydrogenation of the olefinic C=C double bonds while the C-~1 tr~n!e ~onds are preserved. "Preservation of the C~N ~riple ~onds" means in this context that less than 7~, preferably less than 5~, in particular less than 3~ and most preferably less than 1-5~ of the nitrile groups originally present in the polymeric starting product undergo hydrogenation.

The hydrogenated copolymers under discussion here are ~5 o~tained by hydrogenating known alternatingiy or,preferably, randomly structured copolymers of unsaturated nitriles and conjugated dienes while retaining the nitrile groups (e.g.
US-A 3 700 637, DE-A 2 539 132, EP-A 134 023, DE-A 3 046 008 and D~-A 3 227 650).

Example~ of components B include the hydrogenation products of copolymers of at least one unsaturated nitrile such as acrylonitr`ile or methacrylonitrile and at least one LeA 27 153 -;~ J 7~) conjugated diene such as butadiene-(1,3); 2-methylbutadiene-(1,3); 2,3-dimethylbutadiene-(1,3); pentadiene-(1,3) and a product in which part of the conjugated diene units of the above mentioned copolymers is replaced by one or more units 5 of aromatic vinyl compounds,~meth)acrylic acid esters having 1 to 12 carbon atoms in the alcohol component or unsaturated mono- or dicarboxylic acids.

The following are examples of aromatic vinyl compounds:
styrene, substituted styrenes such as o-, m- or p-methyl styrene, ethyl styrene, vinyl naphthalene and vinyl pyridine.
The following are examples of (meth)acrylic acid esters:
methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)-acrylate, 2-ethylhexyl(meth)acrylate and 2-hydroxypropyl-(meth)acrylate. The following are examples of unsaturated carboxylic acids~ -unsaturated monocarboxylic acids containing 3 to 5 carbon atoms, such as acrylic acid, meth-acrylic acid and crotonic acid, Q ,~ -unsaturated dicarboxylic acids containiny 4 or 5 carbon atoms, such as maleic, fumaric, citraconic and itaconic acid, and semiesters of the c,~ -unsaturated dicarhoxylic acids, such as maleic acid n-dodecyl semiester or fumaric acid n-butyl semiester.

The following are examples of other copolymerisable compounds which may be used: vinyl chloride, vinylidene chloride, N-methylol acrylamide, vinyl C1 to C4 alkyl ethers and vinyl esters of carboxylic acids containing l to 18 carbon atoms, such as vinyl acetate or vinyl stearate.

Special examples of the copolymers to be hydrogenated include acrylonitrile-isoprene copolymers, acrylonitrile-isoprene-butadiene copolymers, acrylonitrile-isoprene-n-~utyl acrylate copolymers, acrylonitrile-butadiene-n-hutyl acrylate copolymers, acrylonitrile-butadiene-methyl acrylate copolymers, acrylonitrile-butadiene-2-hydroxypropyl meth-acrylate copolymers and acrylonitrile-butadiene-methacrylic LeA 27 153 .
,: , . , - :. ~

n,~

acid copolymers. Acrylonitrile-butadiene copolymers are particularly preferred.

The degree of hydrogenation of the polymers (percentage of hydrogenated C=C double bonds based on the total number of C--C double ~onds originally present in the polymer) is determined by IR or NMR spectroscopy.

The molecular weights of the hydrogenated nitrile rubbers are from 40,0~0 to 500,000 (g/mol), preferably from 50,000 to 400,000 (g/mol), in particular from 60,000 to 300,000 Ig/mol) (Mw, weight average, determined by gel permeation chromatography).

The Mooney viscosities ~.L (1 ~ 4) 100C of the hydrogenated nitrile rub~ers are generally in the range of from 10 to 150, preferably from 25 to 95 (determined according to DIN
53 523).

Components B may be present in quantities of from 0 5 to 70 parts hy weight, hased on the moulding compound of (A+B).
~hen fillers and reinforcing materials are used, components B are preferably used in quantities of from 5 to 50 parts ~y weight, more preferably from 10 to 4~ parts by weight, especially from 10 to 30 parts by weight, based on the moulding compound (A+B+C).

~n unreinforced polyarylene sulphides, component B is preferahly added in quantities of from 5 to 40 parts by weight, more preferably from 10 to 30 parts by weight and most preferably from 15 to 25 parts by weight. The melt flow properties due to the intrinsic viscosity in both reinforced and unreinforced polyarylene sulphides is still quite marked when the quantity of component ~ used, based on the mou~ding compound, is from 0 5 to 20 parts by weight, preferably from 1 to 15 parts by weight, most preferably from 2 to 10 parts ~y weight.

LeA 27 153 Introduction of the components B used according to the invention into the pol~arylene sulphide moulding compound may be carried out by various methods, e.g. hy mixing of the molten components in extruders or kneaders, but is preferably carried out by melt compounding of the components in a two shaft extruder of Werner 8 Pfleiderer or in an internal kneader.

For ~elt compounding, co~ponents B are used in a dosable form. Powdered rub-bers are preferred. These powders have par~i sl e diameters of from 100/um to 3/um, preferably from 0 1 /um to 2Jum, and are obtained by low temperature milling below the glass temperature of the polymers.Io ~v~d the formation of lum~s, suitable dusting agents are added to these powders in quar.tities of from 1 to 1o% by weight, based on the polymer. Suhstances of this kind are known, e.g. talc, silicas, metal oxides, etc..

The fillers and reinforcing materials used as component may be fihrous or particulate substances which shoulA ~e sufficiently resistant to the temperatures at which the polyarylene sulphides are processed and used. Examples of fibrous materials for this purpose include glass ~ibres, carbon fibres, aramide fibres, metal fibres, etc. Fxamples of particulate suhstances include kaolin, gypsum, chalk, talc, glass balls, mica, quartz, barium sulphate, metal powders, etc.. The reinforcing fibres used are preferably glass fibres or carbon fibres; preferred fillers are: quartz, kaolin, talc and mica.

The fillers and reinforcing agents and other conventional additives are introduced into the moulding compounds of 3~ (A+~) ~y melt compounding. These moulding compounds may be thermo~lastically worked up as granulates in conventional processlnq machines to produce any shaped products.

The mechanical and thermal properties were tested on standard LeA 27 153 2~ 7~
test samples in accordance with DIN or ASTM regulations. The melt viscosities were determined on granulates, using a high pressure capillary viscosimeter.

The mouldiny compounds according to the invention are tougher than other polyarylene sulphides which have been modified to increase their toughness, and they have good temperature and chemical resistance. A pronounced intrinsic viscosity of the polymer melt may be ohtained for processin~
by using suitable quantities of hydrogenated nitrile ru~ber in the moulding compound.

The moulding compounds according to the invention may be i used for the production of moulded articles, sheet products, fi~res and wrapping materials.

LeA 27 153 Example 1 PreParation_of the hvdroqenated nitrile rubbers Acrylonitrile-butadiene copolymers are known.

Hydrogenation of these polymers and analytical determination of their properties may be carried out e.g. by methods analogous to those described in ~P-A134 023.

ExamPle 2 Preparation of the polyarylene sulphide mouldinq comPounds The components are mixed together in the molten state at temperatures from 310C to 330C in a two-shaft ZSK 32 extruder (Werner & Pfleiderer) at a rate of throughput of from 7 to 10 kq/h. ~efore the components were compounded, the hydrogenated nitrile rubber tn the form of sheets was roughly size reduced or if in the fo~m of-bales, it ~as ground to a powder and dusted with dusting agent. The cooled polymer strands were granulated, dried, worked up into moulded products in conventional injection moulding machines and tested in accordance with DI~ regulations.

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L~A ~7 153 * not broken 1) polyphenyle~e sulphide, Bayer AG, Tedu ~, ~m = 95 Pa.s (310C, 103 l/s) 2) hydrogenated nitrile rubber, Therban 1707~, Bayer AG, acrylonitrile content 34%, 75 ML (1l4) 100C

3) Hydrogenated nitrile rubber, Therban 2207 ~ Bayer AG, acrylonitrile content 42,5%, 80 ML (1+4h~00C, ground to a powder and powdered with 6% by weight Vulcasi r from Bayer AG.

4) graft rubber based on acrylate, KM 33 ~, Rohm ~ Haas 5) graft rubber based on silicone, type A1 from DE-A 3 6) Izod impact strength 7) Izod knotched impact strength 8) edge fibre elongation 9) dimensional stability under heat according to ISO 75 A.

LeA 27 153

Claims

1. Moulding compounds containing A) from 30 to 99.5 parts by weight of polyarylene sulphide, preferably polyphenylene sulphide, B) from 0.5 to 70 parts by weight, based on the total weight of the moulding compound (A+B), of hydrogenated nitrile rubber, and optionally C) from 0 to 60 parts by weight, based on the total weight of the moulding compound (A+B+C), of fillers and reinforcing materials.

2. Moulding compounds according to Claim 1, characterised in that the hydrogenated nitrile rubbers are hydrogenated butadiene-acrylonitrile copolymers.

3. Moulding compounds according to Claim 1, characterised in that the degree of hydrogenation of the C= C double bonds in the hydrogenated nitrile rubber is greater than 50% and the bound unsaturated nitrile content is from 10 to 60% by weight.

4. Moulding compounds according to Claim 1, characterised in that the polyarylene sulphide is a polyphenylene sulphide.

5. Moulding compounds according to Claim 1, characterised in that the melt viscosity of the polyphenylene sulphide is greater than 70 Pa.s.

6. Moulding compounds according to Claim 1, characterised in that the proportion of hydrogenated nitrile rubbers is from 5 to 50 parts by weight, based on the moulding compound A+B.

LeA 27 153

7. Moulding compounds according to Claim 1, characterised in that the proportion of hydrogenated nitrile rubbers is from 10 to 30 parts by weight, based on the moulding compound A+B.

8. Use of the moulding compounds according to Claim 1 for the production of moulded articles.

LeA 27 153