US006239221B1

(12) United States Patent Chen

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(75)

(10) Patent N0.: US 6,239,221 B1 (45) Date of Patent: May 29, 2001

LOW GLOSS WEATHERABLE POLYMER

3,489,822

COMPOSITION

4,127,617 4,145,378

Inventor;

Chuan-Ju Chen, Amherst, MA (US)

4,801,646 4,877,826

(73) Assignee: Bayer Antwerpen S.A./N.V., Antwerp (BE) (*)

Notice:

U_S_C_ 154(k)) by 0 days

(21) APPl- N°~1

09/029,326

1/1989 Henton ................................. .. 525/71 Beyer ..... ..

.. 524/377

4,904,730 * 2/1990 Moore et al

525/75

4,912,162 4,946,894 5,112,895 5,397,836 * 5,658,985

Subject to any disclaimer, the term of this patent is extended or adjusted under 35

1/1970 Witt et al. . 11/1978 Arrighetti et al. . 3/1979 Arrighetti et al. . 10/1989

3/1990 8/1990 5/1992 3/1995 8/1997

Kishida et al. .. 525/67 Henton et al. 525/71 Chen et a1- ----------- ~- 524/308 DeNicola, Jr. et al. ............. .. 525/71 Eichenauer et al. ................. .. 525/83

FOREIGN PATENT DOCUMENTS

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PCT Filed:

Sep. 13, 1995

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PCT No.:

PCT/US95/11617

§ 371 Date:

Mar. 3, 1998

§ 102(e) Date: Mar. 3, 1998 (87) PCT Pub No; W097/10301

283611

9/1988 (EP) _

0412370 *

7/1991 (EP) .

* Cited by examiner

Primary Examiner—Jeffrey C. Mullis (74) Attorney, Agent, or Firm—J0seph C. Gil; Aron Preis

PCT Pub. Date: Mar. 20, 1997

(57) (51)

Int. Cl.7 ...................................................... .. C08L 9/02

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US. Cl. ........................ .. 525/193; 525/206; 525/227;

525/233; 525/238; 525/241 (58)

ABSTRACT

Apolymer Composition Comprising a blend of (a) a grafted

ole?n rubber, (b) an ungrafted ole?n rubber, (c) a copoly

Field of Search ................................... .. 525/193, 206,

meric matriX and an Optional (9) a grafted awn/late rubber is

525027, 233, 238, 241

disclosed. The composition Which is characterized in having a desirable balance of impact strength and loW gloss is useful for molding and extrusion of articles for certain outdoor

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References Cited U.S. PATENT DOCUMENTS 3,489,821

1/1970 Witt et al. .

applications. 8 Claims, N0 Drawings

US 6,239,221 B1 1

2

LOW GLOSS WEATHERABLE POLYMER COMPOSITION

in the presence of the rubbery EPDM polymer utiliZing either emulsion, suspension or solution polymeriZation tech niques. Examples of EPDM graft copolymers are taught in US. Pat. Nos. 3,489,821, 3,489,822, 3,642,950 and 4,314,

BACKGROUND OF THE INVENTION

041 all of Which are incorporated herein by reference. Preferred grafted EPDM rubbers have a Weight average particle siZe from 0.1 p to 1.0 p. Most preferred are those

Grafted rubber compositions are Well known in the art.

Poly(acrylonitrile butadiene styrene) or ABS is Widely knoWn and used as a molding and extrusion composition. In

rubbers prepared by grafting the rubber spine in a solution

ABS, polybutadiene is grafted With acrylonitrile and styrene. For outdoor applications Where the polymer composition is exposed to sunlight and Weather, a saturated rubber such as

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polybutyl acrylate (PBA) polyethylene propylene (EP) or

knoWn in the art and described, for example, in US. Pat.

polyethylene propylene diene monomer (EPDM) is used in place of the butadiene used in ABS. Blends of these grafted

Nos. 3,830,878; 4,341,883; 3,944,631; 3691,260 and 4,224, 419, the teachings of Which are incorporated herein by

saturated rubbers are also knoWn.

1. Field of the Invention The present invention is directed to a polymer composi tion Which is a blend of (a) an ole?n rubber such as ethylene

reference. Preferred acrylate rubbers are crosslinked 15

such as ethylene propylene diene monomer rubber (EPDM);

about 10 percent, of a copolymeriZable comonomer. Suitable copolymeriZable comonomers include monovinylidene aro 20

(c) a poly(acrylonitrile styrene) matrix; and (d) optionally a butyl acrylate rubber grafted With styrene and acrylonitrile. suitable as molding and extrusion compounds for certain

matic monomers, e.g. styrene, alpha-methyl styrene, etc., acrylonitrile and alkyl methylacrylates such as methyl meth

acrylate. A preferred acrylate rubber comprises butyl acry late optionally containing various di-and tri-vinyl substi tuted crosslinking and graft enhancing agents present in an

These polymer compositions have a desirable balance of loW

gloss and impact strength Which makes them especially

homopolymers of C1_8 alkyl acrylates, especially butyl acry late or 2-ethylhexyl acrylate, and crosslinked copolymers thereof With up to about 25 Weight percent, preferably up to

propylene diene monomer rubber grafted With styrene and

acrylonitrile (EPDM-g-SAN); (b) an ungrafted ole?n rubber

or suspension process having a particle siZe of from 0.3 p to 0.6 p. Acrylate rubbers for use in the present invention are Well

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amount up to about 5 percent by Weight based on total

rubber Weight. Preferably the acrylate rubber is prepared by an emulsion

outdoor applications. 2. Description of Related Art

process. Emulsion polymeriZed acrylate rubbers may be

Butyl acrylate rubber and EPDM rubbers grafted With

partially agglomerated as is knoWn in the art in order to

styrene and acrylonitrile are Well knoWn in the art. Such

30

provide a greater variety of particle siZe distribution in the

compositions are taught in US. Pat. No. 3,489,822 (Witt et al); US. Pat. No. 4,127,617 (Arrighetti et al); US. Pat. No.

resulting acrylate rubber product thereby controlling gloss

4,145,378 (Arrighetti et al); and US. Pat. No. 4,912,162 (Kishida et al). Blends of a butyl acrylate rubber grafted With

can also be groWn to various siZes by varying the polymer iZation conditions and/or a mixture of previously prepared large and small seed particles may be employed to form the

styrene and acrylonitrile (BA-g-SAN) and an EP or EPDM

and impact properties of the polymer. The rubber particles

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rubber grafted With styrene and acrylonitrile (EP-g-SAN or

grafted rubber. The grafted acrylate rubber’s Weight average

EPDM-g-SAN) are also Well knoWn and are taught in US.

particle diameter is preferably from about 0.05 p to about 0.5

Pat. No. 4,877,826 (Beyer); US. Pat. No. 4,946,894 (Henton

p, most preferably from 0.1 p to 0.25 p. Particle diameters are measured in the latex form of the rubber before grafting

et al) and US. Pat. No. 5,112,895 (C. J. Chen and F. M.

Peng).

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using techniques of transmission Electron Microscopy or hydrodynamic chromatography as disclosed in US. Pat. No.

SUMMARY OF THE INVENTION

4,419,496. Grafting of acrylate rubbers is also Well knoWn

The present invention is directed to molding and extrusion

in the art and is disclosed, for example, in the above cited

compositions Which have loW sheet gloss (less than 50 preferably less than 40 at a 60° angle) and good IZod impact (greater than 50 J/m). The compositions comprise (a) an

US. Pat. Nos. 3,830,878; 4,341,893; 3,944,631; 3,691,260 and 4,224,419. Preferably the crosslinked acrylate rubber is

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grafted by means of an emulsion process.

ole?n rubber grafted With a vinyl aromatic monomer and an

The amount of grafting in both the EPDM and acrylate

unsaturated nitrile monomer and optionally one or more

rubbers may vary over a Wide range. As de?ned by percent

grafting (attached rigid phase Weight/rubber Weight>