Product Information — Tougheners

Polyamide Toughening Using DuPontPolymer Modifiers

Polyamide (nylon) thermoplastic resins offer anexcellent balance of processibility and performanceproperties and therefore are used widely. Of the manytypes of nylon available, the most popular are nylon6 (PA 6) and nylon 6,6 (PA 6,6). However, someend-use applications for these resins requireimproved impact performance at ambient or lowtemperatures. For these applications, toughenedgrades of nylon can be used.

DuPont offers several polymer modifier technolo-gies that can be used for nylon toughening. Thesetechnologies typically combine increased low-tem-perature impact properties, with good adhesion tothe nylon. The adhesion is achieved by the reactionof amine or carboxylic acid end-groups of the nylonpolymer with the functional group of the tougheners.Selected reactions are shown on right:

DuPont polymer modifiers are used in toughened polyamide (nylon) resins, ranging from general-purposegrades to leading supertough formulations.

By varying the amount and type of toughener used, differentlevels of nylon toughness can be achieved. Three categoriesof tougheners are generally recognized:

General-purpose toughener – provides impact strengthmeasured by notched Izod test of about 100 to 210 J/mor about 2 to 4 ft-lb/in. at test temperature.

Intermediate toughener – provides impact strengthmeasured by notched Izod test of about 160 to 320 J/mor about 3 to 6 ft-lb/in. at test temperature.

Super toughener – results in no break in the notchedIzod test, with impact strength typically greater than 800 J/m or greater than 15 ft-lb/in. at the test temperature.

The impact strength measured by notched Izod testingdepends very much on test temperature. Thus, a nylonmodifier may provide super-toughness at room tempera-ture, yet only achieve general-purpose toughness at -40°C(-40°F) test temperatures.

Impact modification of nylon 6

For toughening PA6, DuPont Fusabond® N493 is recommended. The level of toughening depends onthe amount of modifier used. A wide range of toughness,from general purpose to super-toughness, can be obtainedby the varying the amount of Fusabond® (see Figure 1).Super-tough properties can be achieved at 15 wt% ofFusabond® N493.

For intermediate toughening, Surlyn® 9020 is recommendedfor PA6 besides Fusabond® N493 (see Figure 2).Advantages of using Surlyn® modifier include its FDAcompliance (for direct food contact), its low color,excellent surface finish, and short cycle time.

Note: The testing for PA6 modification was made usingUltramid® B-3 (BASF) compounded with a twin screwextruder.

Impact modification of nylon 6,6

For PA6,6 impact modification, DuPont Fusabond® N416 or Fusabond® N493 is recommended.Fusabond® N416 gives good properties for PA6,6due to its relatively high level of high functionality. Thelevel of toughening with various amount of Fusabond®

N416 for PA6,6 is shown in Figure 3.

For intermediate and general purpose toughening ofPA6,6, Surlyn® and Fusabond® modifier products can beused (see Figure 4). Surlyn® 9020 provides outstandingtoughening properties at low level (6.5%). Advantagesof using Surlyn® include its FDA compliance for directfood contact, its low color, excellent surface finish andshort molding cycle time.

Note: The testing for PA6,6 modification was madeusing DuPont Zytel® 101 NC010 compounded with atwin extruder.

Notched Izod of PA6 Modifiedwith Various Levels of Fusabond®N493

1000

800

600

400

200

(18.7)

(15.0)

(11.2)

(7.5)

(3.7)

-50 -40 -30 -20 -10 0 10 20 30 400

Temperature (°C)

N.I

. -

J/m

(ft

-lb

/in

)

20 wt%

10 wt%

15 wt%

6.5 wt%

0 wt%

Fusabond®N MN-493D

Surlyn® 9020

20 wt%

10 wt%

15 wt%

6.5 wt%

Notched Izod of PA6 Modified withFusabond®N493, Surlyn® 9020 at 6.5 wt%Level

-50 -40 -30 -20 -10 0 10 20 30Temperature (°C)

250(4.7)

200(3.7)

150(2.8)

100(1.9)

50(0.9)

N.I. -

J/m

(ft

-lb

/in

)

Notched Izod of PA6,6 Modifiedwith Various Levels of Fusabond®N4161200.0

(22.5)

1000.0(18.7)

800.0(15.0)

600.0(11.2)

400.0(7.5)

200.0(3.7)

0.0-30 -20 -10 0 10 20 30 40-40-50

Temperature (°C)

N.I. -

J/m

(ft

-lb

/in

)

Surlyn® 9020

Fusabond® MN-493D

Surlyn® 9950

Notched Izod of PA6,6 Modified with Surlyn® and Fusabond® at 6.5 wt% Level

160(3.0)

150(2.8)

140(2.6)

130(2.4)

120(2.2)

110(2.1)

100(1.9)

90(1.7)

-50 -40 -30 -20 -10 0 10 20 30

Temperature (°C)

N.I. -

J/m

(ft

-lb

/in

)

Figure 3

Figure 2

Figure 1

Figure 4

Effect of toughener on other properties

Stiffness – The stiffness of a toughened nylon decreasesas more toughener is added. This can be seen in proper-ties such as flex modulus and tensile strength, whichtend to decrease as the toughener level increases.Figures 5 and 6 plot the relationship between flex modu-lus and toughener level for PA6 and PA6,6.

Viscosity – Toughened nylon normally has a higher vis-cosity than untoughened grades, which may require thatprocessors adjust injection molding conditions. Figure 7shows how viscosity changes in relation to toughener level.

Glass-filled polyamide

Glass fibers can be added to increase nylon stiffness.However, properties such as elongation and impactstrength are reduced by adding glass fiber. Using atoughener in a glass-filled nylon can improve its elonga-tion and impact strength.

Figure 8 graphs the impact strength of PA6 (BASFUltramid® B-3) with 33% glass fiber (PPG 3660) forvarious loadings of DuPont Fusabond® N493. As mentioned above, flex modulus decreases with highertoughener levels. The same trend in physical propertiesholds true for lower levels of glass.

Factors influencing performance

The level of toughener used in nylon compound is theprimary factor influencing its overall performance. Alsoimportant are the type of mixing used to compound thenylon, and the type of toughener used.

In general, better mixing leads to better performance. A twin-screw extruder is better than a single-screwextruder. A single screw with a mixing screw and a vacuum port is much better than a single screw with ageneral-purpose screw.

Figure 7

Figure 6

Figure 5

Figure 8

Notched Izod & Flex ModulusPA6 Modified with Fusabond®N493

10003,500

3,000

2,500

2,000

1,500

1,000

(18.7)

800

(15.0)

600

(11.2)

400

(7.5)

200

(3.7)

00 5 10 15 20

Wt% Fusabond® N MF-493D

N.I

. at

23

°C -

J/m

(ft

-lb

/in

)

Notched Izod & Flex ModulusPA6,6 Modified with Fusabond®N416

1200(22.5)

1000(18.7)

800(15.0)

600(11.2)

400(7.5)

200(3.7)

0

3,500

3,000

2,500

2,000

1,500

1,000

0.0% 5.0% 10.0% 15.0% 20.0% 2.50%

Wt% Fusabond® N MF-416D

N.I. at

23

°C -

J/m

(ft

-lb

/in

)

Fle

x M

od

ulu

s -

Mp

a (

psi)

Fle

x M

od

ulu

s

- M

pa (

psi)

Viscosity vs Shear rate at 260°C of PA6for Various Levels of Fusabond®N493

10000

1000

100

10

1 10 100 1000 10000

Shear Rate sec-1

Vis

co

sit

y P

a-s

ec

0 Wt%

15 Wt%

20 Wt%

Notched Izod & Flex Modulus 33% Glass Filled PA6 Modified with Fusabond®N493

350(6.6)

300(5.6)

250(4.7)

200(3.7)

150(2.8)

100(1.9)

50(0.9)

0

7500

7000

6500

6000

5500

5000

4500

40000 15 25

Wt% Fusabond® N MN-493D per PA6

N.I. at

23

°C -

J/m

(ft

-lb

/in

)

Fle

x M

od

ulu

s -

Mp

a (

psi)

H-XXXXX-X

DuPont Worldwide Toll-free (U.S.A.) 800 438-7225

United States

DuPont Packaging andIndustrial Polymers,Barley Mill Plaza 26-2122P.O. Box 80026Wilmington, DE 19880-0026Telephone (302) 992-5225Fax (302) 992-3495

Canada

DuPont Canada Inc.P.O. Box 2200, Streetsville7070 Mississauga RoadMississauga, ONT L5M 2H3Telephone (Canada Only)(800) 268-3943/(905) 821-5953Fax (905) 821 5230

Brazil/South America

DuPont do Brasil, S.A.Alameda Itapecuru, 50606454-080 Barueri, SP BrasilTelephone 55 (11) 7266 8542Fax 55 (11) 7266 8720

Europe

DuPont de Nemours Int’l. S.A.2, Chemin du Pavillon Box 50CH-1218 Le Grand SaconnexGeneva, SwitzerlandTelephone (022) 717 51 11Fax (022) 717 55 00

Internet/World Wide Web:

http://www.dupont.com/industrial-polymersE-Mail:

industrial.polymers@dupont.com

Mexico/Central America

DuPont, S.A. de C.V.Homero 206 Anexo Planta AltaCol. Chapultepec Morales11570, D.F. MexicoTelephone (525) 722 1000Fax (525) 722 1308

Asia Pacific

DuPont Singapore PTE Ltd.1 Maritime Square #07-01World Trade CentreSingapore 099253Telephone (65) 273 2244Fax (65) 272 7494

Japan

Mitsui-DuPont Polychemicals Co., Ltd.Kasumigaseki Bldg. 24F3-2-5 KasumigasekiChiyoda-ku, Tokyo 100, JapanTelephone (813) 3580 5531Fax (813) 3592 1540

Australia

DuPont (Australia) Ltd.254 Canterbury RoadBayswater, Victoria 3153AustraliaTelephone (3) 9721 5900Fax (3) 9721 5650

The technical data contained herein are guides to the use of DuPont resins. The advice contained herein is based upon tests and information believed to be reliable, but users should notrely upon it absolutely for specific applications because performance properties will vary with processing conditions. It is given and accepted at user’s risk and confirmation of its validityand suitability in particular cases should be obtained independently. The DuPont Company makes no guarantees of results and assumes no obligations or liability in connection with itsadvice. This publication is not to be taken as a license to operate under, or recommendation to infringe, any patents. CAUTION: Do not use in medical applications involving permanentimplantation in the human body. For other medical applications, request DuPont publication H-50102, “DuPont Medical Caution Statement.”