CA1084195A

CA1084195A - Composition of a polyphenylene ether resin, homopolystyrene and an a-b- a.sup.1 block copolymer

Info

Publication number: CA1084195A
Application number: CA249,393A
Authority: CA
Inventors: Visvaldis Abolins; Gim F. Lee, Jr.; Arthur Katchman; William R. Haaf
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1975-04-01
Filing date: 1976-04-01
Publication date: 1980-08-19
Also published as: JPS51129450A; DE2613941A1; FR2306235A1; NL181507B; NL7603428A; FR2306235B1; AU509228B2; NL181507C; AU1256276A; GB1532455A

Abstract

ABSTRACT OF THE DISCLOSURE
This invention provides novel compositions of a polyphenylene ether resin, homopolystyrene resin and an A-B-A1 block copolymer wherein the ration of polyphenylene ether to homopolystyrene is less than one. The composition may be utilized in many different shapes as it may be molded into three-dimensional plastic articles using conventional techniques.

Description

~ 4~95 8CH-2210 Novel compositions are described which consist essen- ; !
. .; .
tially of a polyphenylene ether resin, a homopolystyrene resin and a A-B-Al block copolymer wherein the ratio of polyphenylene ether resin of homopolystyrene is less than ;~
one.
The polyphenylene ethers and processes for their preparation are well known in the art. They are described in numerous publications including the Hay U.S. patents 3,306,874 dated February 28, 1967 and 3,306,875 dated February 28, 1967 Also the Bennett and Cooper U.S.
patents 3,639,656 dated February 1, 1972; U S 3,642,699 dated Febrauary 15, 1972 and U.S. 3,661,848 dated May/9/1972.
In the Hay Patents, the polyphenylene ethers are prepared by an oxidative coupling reaction comprising passing an oxygen-containing gas through a reaction solution of a phenol and a metal-amine complex catalyst. Other dis closures relating to process for preparing polyphenylene -ether resins, including graft copolymer3 of polyphenylene ethers with styrene type compounds, are found in Fox, U S 3,356,761 dated December 5, 1967: Sumitomo U.K. 1,291,609, Bussink et al, U.S. 3,337,499 dated August 22, 1967, Blanchard et al, U.S. 3,219,626 dated November 23, 1965;
Laakso et al U S. 3,342,892 dated September 19, 1967 Borman, U.S 3,344,166 dated September 26, 1967, Hori et al, U S 384,619 dated May 21, 1968 Faurote et al, U S
3,440,217 dated April 22, 1969; and disclosures relating to metal based catalysts which do not include amines, are known from patents such as Wieden et al, U S 3,442,885 dated May 6, 1969 (copper-amidines): ~akashio et al, U.S
3,573,257 dated March 30, 1971 (metal_alcoholate or _ phenolate): Kobayashi et al, U.S. 3,455,880 dated July/15/69 (cobalt chelates); and the lik~. In the Stamatoff patents, _ 1 --~84~95 8CH-2210 the polyphenylene ethers are produced by reacting the corresponding phenolate ion with an initiator, such as peroxy acid salt, an acid peroxide, a hypohalite, and the like, in the presence of a complexing agent Dis-closures relating to non-catalytic processes, such as oxidation with lead dioxide, silver oxide, etc ~ are dis-cribed in Price et al, U.S. 3,382,212 dated May 7, 1968.
Cizek, U S. 3,383,435 dated May 14, 1968 discloses poly-phenylene ether-styrene resin composition and Lauchlan, U S
3,660,531 dated May 2, 1972 discloses compositions of a polyphenylene ether resin, elastomeric block copolymers and polyætyrene resins In applicant's German Application P 2~255~930 filed November 15, 1972, there are disclosed compositions which may include a polyp~enylene ether resin, a styrene resin and A-B-A blOCk type copolymers These compositions were generally disclosed as containing 1 to 9~% by weight of polyphenylene ether resin, from 0 to 6~%
by weight of styrene resin and from 10 to 80% by weight of A-B-A block copolymer. In the examples of that application, there are disclosed compositions which contain mixtures of homopolystyrene and high-impact rubber-modified polystyrene in combination with polyphenylene ether resin and an A-B-A block copolymer It has now been found that when compositions of a polyphenylene ether resin, a A_B-A block copolymer, and a homopolystyrene resin are prepared which have a polyphenylene ether to homopolysty-rene resin ratio of less than 1:1 and preferably less than 1:2 have improved properties which make them attractive :: molding compositions. These properties include improved - 30 processability, better ultraviolet stability and im-proved gloss. In addition, it has been found that these compositions have axcellent impact strengths which are 1~84195 substantially equivalent to compositions prepared with high-impact rubber-modified polystyrene.
Accordingly, it is a primary object of this invention to provide novel compositions of a polyphenylene ether resin, and an A-B-A copolymer and homopolystyrene which have improved stability and processability. The compositions of the invention are normally solid and thermoplastic.
They consist essentially of:
(a) from 5 to 45 parts by weight of polyphenylene ether resin;
(b) from 50 to 85 parts by weight of a homopoly-styrene resin with the proviso that the ratio of poly-phenylene ether resin to homopolystyrene resin-is less than l:ls and (c) from 5 to 35 parts by weight of an elastomeric block copolymer of a vinyl aromatic compound (A) and (A) and a conjugated diene (b), of the A-B-Al type, the center block (B) being of higher molecular weight than that of combined terminal blocks (A) and (A)l The preferred polyphenylene ether resin is selected from polyphenylene ether resins having the formula:

~0 ~_ :

wherein the oxygen ether atom of one unit is connected to the benzene nucleus of the next adjoining unit: n is an integer of at least 50; and each Q is a monovalent sub-stitute selecte~ from hydrogen, halogen, hydrocarbonradicals having at least two carbon atoms between the halogen atom and the phenyl nucleus.

1~8~195 The preferred polymers are when each Q is alkyl of from 1 to 4 carbon atoms and especially preferable is poly ~2,6- dimethyl-1,4-phenylene ether).
The elastomeric block copolymers of vinyl aromatic compounds and conjugated dienes are made by means well known in the art and are also available commercially from a number of sources Block copolymers of vinyl aromatic compounds and conjugated dienes are described in Kennedy, et al Editor, Polymer Chemistry of Synthetic Elastomers, Interscience, Vol. 23, Part II, 1969, pages 553-559. In general, they will be of the A-B_Al type in which the center and end blocks can vary In the compositions of this invention, the central block B, will always be that of a conjugated diene, e.g., butadiene; isoprene; 1-3-pentadiene; 2,3_dimethyl-butadiene, and the like or mixtures of the foregoing. m e terminal blocks A and A , will be the same or different, but will always be derived from a vinyl aromatic compound, e.g., styrene, o~-methyl styrene, vinyl toluene, vinyl xylene, vinyl naphthalene, or mixtures of any of the foregoing.
In the most preferred compositions, the block copolymer will have terminal blocks A and A comprised of polys-tyrene and center block B comprises of polybutadiene.
The ratio of the comonomers can vary broadly, so long as the molecular weight center block is greater than that of the combined terminal blocks. This appears to be necessary for the impact strength and solvent resistance to be maximized. Preferably, with the above limitation, the molecular weight of the terminal blocks each will range from about 2000 to about 100,000, while that of the center block will range from about 25,000 to about 1,000,000.
The block copolymers are made by an organometallic in-i i~84195 8CH-2210 itiated polymerization process using, for example, sodium or lithium metal an organic derivative thereof. The diene ~
monomers can be polymerized with a monofunctional or ~`
difunctional initiator, as is described in Kennedy et al, mentioned above.
In one process, the block copolymer is prepared by dis~olving the conjugated diene, e.g., butadiene, in an aromatic hydrocarbon solvent, e.g., xylene, toluene, etc., and adding 0.3 to 7 5 millimoles/100 parts of monomer of an organodilithium initiator, e g , dilithiobutane, dilithi-ostilbene, etc Polymerization of the diene is completéd and then the vinyl aromatic compound i5 added and poly_ merization of this is completed to form the block copo~ymer The product is precipitated and deactivated, e.g., with alcohol, such as ethanol or isopropanol and purified by redissolving in hydrocarbon and reprecipitating with alochol.
Full descriptive details of such a process are given ~;
in Zelinski, U.S. Patent 3,251,905 dated May 31, 1966.
In another process, the block copolymer is built up se~uentially uqing, e.g, a secondary or tertiary alky-llithium compound at about 100-200 parts per million based ~-;
on the total weight of the monomers and a polymerization temperature in the range 20-65 C For example, styrene is t dissolved in cyclohexane at 32C. and treated with 5530 parts per million of secondary butyl lithium. After poly-merization is complete, isoprene is injected and poly-merization is continued at 55_57 C. Finally styrene is added and the third bloc~ is polymerized. The product can be recovered as descrived above.
Full descriptive details of such a process are given in Holden et al U.S patent ~o. 3,231,635 dated Jan/25/1966 ~ 19~ 8CH-2210 Such styrene-butadiene-styrene block copolymer resins alone and blended with rubber-modified styrene resins are ~`
also available commercially, e.g., as Kraton( ) X-4119, K-1102, K-llOl, XT-0135 and XT-0401 or K-1107 and K-1108 (styrene-isoprenestyrene) from Shell Chemical Company, Polymers Division.
The homopolystyrenes are well known and are commercially available as "crystal" polystyrene. The average molecular weight of these materials may vary from 20,000 to 500,000 but most commercially available resins will have a molecular weight between 200,000 and 250,000.
The compositions of the invention will consist essentially of from 5 to 45 parts by weight of a polyphenylene ether resin or more preferably from 10 to 40 parts by weight of the polyphenylene ether resin; from 50 to 85 parts by -weight of a homopolystyrene resin or more preferably from 60 to 80 parts by weight with the proviso that the ratio of polyphenylene ether resin to homopolystyrene resin is less than 1:1, more preferably less than 1:2 or most preferably between the ratio of 1:2 and 1:6; and from 5 to 35 parts by weight of the A-B-Al block copolymer or more preferably from 7.5 to 15 parts by weight of said A-B-A
block copolymer.
The compositions of the invention may also include conventional flame retardants, processing aids, bulk fillers and reinforcing fillers*. Fibrous glass is a preferred reinforcing filler and from 1 to 80% preferably from 10 to 40% by weight may be employed.
* Modern Plastics Ency. Vol. 50 No. lOA (1973) pp 210-214 and pp 232-236 disclose many suitable reinforcements and flame retardants.

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~8419~ 8CH-2210 The manner of making the compositions of this in-vention is not critical, is conventional and will be obvious to those skilled in the art. Each of the components may be added as part of a blend premix and this premix may then be mixed, e.gO, by passage through an extruder, or by `
fluxing on a mill, at a temperature dependent on the needs of the particular compositions. The mixed composition may be cooled and cup up into molding granules and molded or extruder or formed into any desired shape. Typical process-ing and molding techniques will be illustrated hereinafter.
It is to be understood that the compositions of this invention can be used in many different ultimate shapes.
For example, they may be molded into three-dimensional articles using conventional techniques.
The compositions described in Table I were prepared by preblending the components, extruding the blend and molding test pieces The units which refer to the specific ~
materials indicate the amount in parts by weight. All - ~`
compositions included 1.5 parts by weight of polyethylene and 0.5 part~ by weight of tridecylphosphite. The Izod impact values refer to ft. lbs./in and the Gardner impact (drop dart) values are in inch lbs.

.
: .

_ 7 _ 1~8419~ 8CH-2210 TABLE I
"
poly(2,6-dimethyl homopoly- A-B-Alblock HDT Izod Impact 1~4-ph~e2nylenestyrene copolvmer4 F 73F -40F

1. 15 60 25 218 5,1 1.8

2, 20 55 25 227 5.4 1.9

3, 25 50 25 236 4,7 2,4 :

4, 30 45 25 244 5,1 3,2 2, PP0, General Electric Co., having a I,Y, of about 0,5 in . CHC13 at 30C, B 3, Dylene 8G, Sinclair Koppers 4, Kraton 11101, Shell Chemical Co, low molecular weight styrene-butadienestyrene block copolymer, TABLE I (Cont's) Gardner Impact Tensile 73 F -40F Elongation %
-1. 123 126 73 2. 150 114 59 3, 156 123 52 4, 132 132 61 EXAMPLE II
:
Additional compositions were prepared according to the procedures of Example I which had the compositions and proper- :~ .
ties listed in Table 2. The gloss values are 45 surface gloss expressed as relative dimensionless units, The units which refer to the specific materials indicate parts by weight.

':
.

1~8419~; 8CH-2210 TABLE II

poly(2,6-dimethyl- homopoly- A-B-A blo~k Hips5 Gloss 1,4-phenylene styrene copolymer _ ether)2

5.* 15 0 0 85 44.8

6.* 15 85 0 __ 56.9

7. 15 70 15 -- 41.8

8 15 60 25 -- 31.9

9. 15 50 35 _- 32 0 2 As in Table I
3 As in Table I
4. Kraton X-4119, Shell Chemical Co, styrene-butadiene-styrene pbw block copolymer with 2096 mineral oil.
5. High impact rubber modified polystyrene, Foster Grant 834 * control ; r TABLE II (Cont!d) ;
Izod Gardner Tensile 73F_40F 739F _40FElongation %
5.* 2.4 1.1 31 19 45 6.* 0.5 0.4 5 4 6 ;~
7 3.1 1.1 34 31 42 8 5.2 2.4 132 96 43 9. 6.7 4.4 150 177 42 The following compositions were prepared and were subjected to physical testing All units that refer to specific materials are parts by weight.
.

8CH-2210 ~

10*1l ~ `
poly(2,6-dimethyl- 2 1,4-phenylene ether) 45 45 hips 55 __ A_B-A block copolymer -- 7.1 homopolystyrene5 __49,9 * control 2, As in Example I
3. As in Example II
4, As in Example I
5. As in Example I, Both compositions contained 1 pbw of tridecylphosphite, 1,5 pbw of polyethylene, 0,15 pbw of zinc sulfide and 0,15 -pbw of zinc oxide, These compositions were found to have the following physical properties:

*10 11 : .. , Tensile Str, Yield (psi)9,300 10,600 Tensile Str, Ult,(psi) 8,500 8,400 Elongation (%) 79 ~,46 Flexural Str,(psi) 13,800 15,700 Flexural Mod ~psi) 367,000 385,300 Izod Imp, at 73F(ft,lb,/in,n,) 4,1 3,3 Izod Imp.at _40oF(ft~lbs./in.n) 1~8 I,5 Gardner Imp (in-lb) 190 175 Heat Distortion Temp ( F)253 261-262 Melt Viscosity at 1500 sec 540F (poise) 2,300 2,680 Gloss 45.3 61.5 Hardness, Rockwell 116,8 120,0 * control The following compositions were prepared and wera subjected to physical testing. All compo~itions contained 9 ~-~
pbw of triphenylphosphate, 1 pbw of polyethylene, 0.15 pbw of zinc sul~ide, 0.15 of zinc oxide. The units that refer to specific materials are parts by weight.

poly(2,6-dimethyl 2 1,4 phenylene ether) 40 40 40 40 homopolystyrene3 50 51.9 45 45 ~Kraton" 1101 10 - - - - - -"Kration" 1107 _ _ 8.1 15 - -"Kraton" 11026 - - - - - - 15 2. As in Example I
3 As in Example I -4 Shell Chemical Co. styrene-butadiene-styrene block Copolymer 5. Shell Chemical Co. styrene-isoprene-styrene block 6. Shell Chemical Co styrene-butadiene-styrene block copolymer These compositions had the ~ollowing physical properties:

- 11 -108419~ 8CH-2210 These compositions had the following physical properties:

12 13 14 15 Tensile Str,,Yield (psi)8~8009,400 8,100 7,800 Tensile Str., Ult.(psi)7,200 7,600 7,100 7,400 Elongation (%) 50 50 66 77 Flexural Str. (psi)13,400 13,200 12,100 11,000 Flexural Mod (psi)400,800 377,600370,900 364,500 Izod Imp at _40 F
(ft, lb/in,n,) 1,6 1,3 2,7 2,3 Izod Imp, at 73F
(ft~ lb./in,n,) 4,8 4,0 6,5 6,0 Gardner Impact,(in-lb,)245 175 225 225 Heat Distortion Temp,( F) 212 214 215 215 UL Subject 94*,1/6" V-1(16,8) V-1(13,8) FAILSFAILS
Melt Viscosity at 1500 sec 540F (poise) I650 1590 1850 1850 Gloss 60,0 61,0 57,8 54,5 Hardness,Rockwell R 115,0 116,5 110,2 110,5 * Values in parenthesis-average burning time, The following compositions were prepared and were subjected to physical testing, A,. compositions contained 8 pbw of tri-phenylphosphate, 1.0 pbw of tridecylphosphite, 1.5 pbw of poly-ethylene, 0.15 pbw of zinc sulfide and 0.15 pbw of zinc oxide, The units that refer to specific materials are parts by weight.

6*17 18 19 20 .. ;,~
poly)2,6-dimethYl- 2 1,4 phenylene ether) 4040 40 40 40 ~
hips 60__ __ __ __ r homopolystyrene -- 55 52.3 50 45 A_B_Al block .
copolymer _ - 5 7,7 10 15 2. As in Example I
3, As in Example II
4, As in Example I
5, As in Example I
* control m e compositions had the following physical properties:

8CH-2210 ~
10841~5 16* 17 18 19 20 Tensile Str.
Yield (p8i)7,500 9,900 9,100 8,800 8,100 Tensile Str.
Ult (psi) 7,200 7,900 7,300 7,200 7,000 Elongation (%) 76 69 44 50 60 Flexural St~ (psi)10,700 1~,500 13,200 13,400 12,300 Flexural Mod (psi)356,000401,500 377,600 400,800364,000 Izod Imp.
at 37F -(ft. lb/in.n.) 4.0 2.2 4.1 4.8 6.1 Izod Imp, at _40F (ft.lb./
in.n.) 1.7 1.0 1.4 1.6 2.6 Gardner Imp.
(in_lb) 185 105 205 245 235 -Heat Distortion Temp.(F) 211 212 211 212 213 ~;
U L sub2ect g4a; 1/6 V-1(12 1) V-1(9 6) V-1(10 7) V-1(16 8) V-1~17.3) Melt Viscosity at 1500 seC-l, 540F (poise)1,390 1,390 1,540 1,650 1,800 Gloss 50 63.5 61.5 60 57.6 Hardness - -Rockwell,R112.0 119.0 116.2 115.0 115.0 a Values in parentheses - average burning time.
* control The compositions lised in Table III were prepared ac-cording to the methods used for the preparation of the samples that are listed in Examples I-V. The melt viscosity was determined at 540F and 1500 sec 1 (poise). The Yellowness Index is an initial Yellowness Index expressed as a relative unitless dimension as defined by ASTM The change in Yellow-ness Index is the recorded increase in Yellowness Index after _ 14 -poly(2,6-dimethyl- homopoly_ A~B-Al Flexural 1,4-phe~ylene ~y~ene blocX 5 ~dulus(psi1 ethere) . op~lymer .:.-3 21 15 803 5 449,000 ~ ;
22 15 753 10 448,000 23. 15 70 15 403,000 24. 15 603 25 318,000 603 5 449,000 26 35 553 10 430,000 27. 35 503 15 397,000 28 35 403 25 301,000 29.* 35 554 10 413,000 30.* 35 504 15 3~7,000 31. 55 403 5 450,000 32 * 55 253 10 394,000 33 * 55 303 15 382,000 34.* 55 354 10 377,000 35.* 55 304 15 351,000 * Control 2 As in Example I
3 As in Example I
4. KTPL - 5 grade of homopolystyrene from Arco 5. Kraton 1101 styrene-butadiene-styrene block copolymer ~ ~ 8CH-2210 TABLE IIT (Cont's) Melt Viscosity Yellowness Index Change in (noises) Yellowness Index 22 1350 21 6 0.8 23. 1550 21.7 1.3 :~
24. 1550 21 5 2 6 25. 1800 28.6 10.3 26. 2130 28 7 14.7 27 2430 28 6 17.5 28. 2450 28.0 18 4 29.* 1350 31.8 10.6 30.* 1520 29 1 14.6 31.* 2830 32.2 31.3 32 * 3600 32.5 33 0 33.* 3000 34.1 29.8 34 * 3000 34.1 29.8 ::
35.* 3450 33.7 31.0 A comparision of the listed physical properties of control samples with the listed physical properties of the samples of the invention makes it clear that the compositions of the present invention have reduced melt viscosity, enhanced stability and better gloss than the control examples.
Obviously, other modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.

_ 16 -

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A normally solid thermoplastic composition which consists essentially of:
(a) from 5 to 45 parts by weight of a polyphenylene ether resin;
(b) from 50 to 85 parts by weight of a homopoly-styrene resin with the proviso that the ratio of polyphenylene ether to homopolystyrene is less than 1:1; and (c) from 5 to 35 parts by weight of an elastomeric block copolymer of a vinyl aromatic compound (A) and (A)1 and a conjugated diene (B), of the A-B-A1 type, the center block (B) being of higher molecular weight than that of combined terminal blocks (A) and (A)1.

2 A composition as defined in claim 1 wherein com-ponent (a) is a polyphenylene ether of the formula:

wherein the oxygen ether atom of one unit is connected to the benzene nucleus of the next adjoining unit; n is an integer of at least 50; and each Q is a monovalent substituent selected from hydrogen, hydrocarbon radicals, halohydro-carbon radicals having at least two carbon atoms between the halogen atom and the phenyl nucleus, hydrocarbonoxy radicals and halohydrocarbonoxy radicals having at least two carbon atoms between the halogen atom and the phenyl nucleus.

3. A composition as defined in claim 1 wherein each Q
is alkyl having from 1 to 4 carbon atoms.

4. A composition as defined in claim 2 where each Q
is methyl.

5. A composition as defined in claim 1 wherein, in component (b), (A) and (A)1 are selected from styrene, .alpha.-methyl styrene, vinyl toluene, vinyl xylene and vinyl naphthalene and (B) is selected from butadiene, isoprene, 1,3-pentadiene or 2,3-dimethylbutadiene.

6. A composition as defined in claim 5 wherein, in component (c), (A), is a styrene block (B) is a butadiene block and (A)1 is a styrene block.

7. A composition as defined in claim 6 wherein in component (b) terminal blocks (A) and (A)1 have molecular weights of 2,000 to 100,000 respectively, and center block B
has a molecular weight of from 25,000 to 1,000,000.

8. A composition as defined in claim 1 which consists essentially of:
(a) 10 to 40 parts by weight of a polyphenylene ether of the formula:

wherein Q is alkyl of from 1 to 4 carbon atoms and n is an integer of at least 50;
(b) 60 to 80 parts by weight of homopolystyrene resin;
and (c) from 7.5 to 15 parts by weight of an elastomeric block copolymer of a vinyl aromatic compound (A) and (A)1 and a conjugated diene (B), of the A-B-A1 type, the center block B
being of higher molecular weight than that of the combined terminal blocks A and A1.

9. A composition as defined in claim 8 wherein the elastomeric block copolymer is a block copolymer of styrenebutadiene-styrene.

10. A composition as defined in claim 1 which includes a reinforcing amount of reinforcing filler.

11. A composition as defined in claim 10 which includes a reinforcing amount of fibrious glass.

12. A composition as defined in claim 1 which includes a flame retardant amount of a flame retardant.

13. A normally solid thermoplastic composition which consists essentially of:
(a) from 5 to 45 parts by weight of poly(2,6-dimethyl-1,4-phenylene ether) resin;
(b) from 50 to 85 parts by weight of a homopolystyrene resin with the proviso that the ratio of poly(2,6-dimethyl-1,40 phenylene ether) resin to homopolystyrene resin is less than 1:1; and (c) from 5 to 35 parts by weight of an elastomeric block copolymer of a vinyl aromatic compound (A) and (A)1 and a conjugated diene (b), of the A-B-A1 type wherein (A) is a styrene block, (B) is a butadiene block and (A)1 is a styrene block, the center block (B) being of higher molecular weight than that of combined terminal blocks (A) and (A)1 and terminal blocks (A) and (A)1 having molecular weights of 2,000 to 100,000 respectively, and center block having a molecular weight of from 25,000 to 1,000,000.

14. A composition as defined in claim 13 wherein the ratio of poly (2,6-dimethyl-1,4-phenylene ether) resin to homo-polystyrene resin is less than 1:2.