Compounding With Viton Curative Masterbatches

Transcription

1 Technical Information Compounding With Viton Curative Masterbatches Introduction The bisphenol cure system provides a unique combination of excellent processing safety and fast cure rates, together with superior resistance to compression set, particularly when compared to the older, diamine types of curatives which were commonly used in fluoroelastomers prior to the 97's. A number of Viton products are offered which contain the bisphenol cure system, and are referred to as 'precompounds'. The accelerator and crosslinking agent are incorporated into the polymers in precisely controlled amounts in DuPont Dow Elastomers production facilities. Examples of such products are Viton E-C, E-, and B-9. The advantages provided by precompounds include elimination of the need for inventorying, weighing, and incorporating two ingredients, the accelerator and the crosslinking agent. The same bisphenol curing system which is contained in Viton precompounds, such as Viton E-C, E-, and B-9, is available in masterbatch form, for use in Viton gum polymers. The cure system accelerator masterbatch is called Viton Curative No., and the crosslinking agent masterbatch is called Viton Curative No.. Some of the advantages in using the separate curative masterbatches include: more latitude in formulating compounds easier development of proprietary formulations easier to develop compounds to fit specific processing or property needs fewer types of Viton polymer to inventory possible to vary processing and vulcanizate property characteristics of current curative-containing polymers Product Description The masterbatch approach was taken with these curative chemicals to avoid handling powdered chemicals as well as to avoid some of the weighing errors that are made when using very small amounts of critical ingredients. A Viton fluoroelastomer is used as the base for the masterbatches to provide easy dispersion and to eliminate possible adverse effects on vulcanizate properties from other extenders. The curative masterbatches are in a free-flowing form for easy handling, weighing, and premixing with Viton polymers. A product description is shown below. Viton Curative No. No. Composition % Organophos- % Dihydroxy phonium salt + 7% aromatic compound fluoroelastomer + % fluoroelastomer Specific Gravity at / C(77 F).. Color White to off-white Tan to gray-brown Form Free-flowing particles Free-flowing particles Note: Information on Viton Curative No. can be found in DuPont Dow Elastomers technical bulletin VT 8.VC.

2 Handling Precautions Viton Curative Masterbatch No. contains an ingredient that is toxic by oral ingestion (ALD = mg/kg) and produces harmful vapors at temperatures above C (9 F). Viton Curative No. is a mild skin irritants to guinea pigs but do not cause sensitization. Curative No. may be irritating to the skin of guinea pigs but is not a sensitizer. For a review of handling precautions covering the Viton polymers themselves, read DuPont Dow Elastomers technical bulletin H-79-, Handling Precautions for Viton and Related Chemicals. The following general recommendations apply to the Viton Curative Masterbatches. WARNING! FIRST AID: SPILL: May cause irritation. Harmful vapors may be released during processing above C (9 F). Avoid contact with eyes, skin, and clothing. Avoid breathing vapors. Use with adequate ventilation. Wash thoroughly after handling. IN CASE OF CONTACT, immediately flush eyes with plenty of water for at least min. Call a physician. Flush skin with water. SWEEP UP and remove. Using Viton Curative Masterbatches The Viton Curative Masterbatches can be used to cure a wide variety of base Viton polymers. In addition, Viton Curative No. can be used to accelerate the cure rate of the curative-containing polymers. Viton Curative No. and No. are the two curatives used in Viton E-C, E-, and B-9. Duplicating Commercially Available Curative-Containing Polymers Products similar to the commercially available curative-containing polymers can be made using the following recipes: Viton Viton Viton Polymer E-C E- B-9 Viton E- 9. Viton E- 9. Viton B 9. Viton Curative No... Viton Curative No...8 In these recipes, the base polymer has been reduced to account for the level of Viton Curative Masterbatches being added. Some compounders may simply build the recipe on parts of the Viton polymer being used. Little or no difference in processing or properties has been noted in either case. Mixing Compounds of Viton Using Curative Masterbatches When mill mixing, it is suggested that the base polymer be banded first, followed by addition of the masterbatches. Premixing of the masterbatches with a small portion of the filler before adding to the band will prevent any popping of the masterbatch particles. The polymer and masterbatches should be well blended before adding any other ingredients. In the case of internal mixing of Viton, it is suggested that the curative masterbatches be added along with the base polymer. This procedure will ensure good dispersion of the curative masterbatches. In some formulations, where scorch is a problem, it may be necessary to withhold the curative masterbatches from the internal mixer. These can then be added during a short second pass in the internal mixer or on a mill. Other mixing, processing and curing procedures will be the same as those described in DuPont Dow Elastomers technical bulletin H-78-, Processing Viton E-C Fluoroelastomer. Effect of Viton Curative No. and No. on Processing and Vulcanizate Properties of Various Viton Polymers A table of data and a series of contours based on this and other data have been developed to illustrate the versatility that can be achieved with Viton Curative Nos. and in a variety of base Viton polymers. The following combinations are shown: Table Figure Viton Viton No. No. Polymer Curative thru 9 E- No. and No. thru 8 E- No. and No. 9 thru 7 A-HV No. and No. 8 thru B No. and No. Actual results obtained using specific levels of Viton Curative No. and No. in a typical compound with Viton E- are shown in Table. Figures through 9 show the contour plots developed from these and other data. Each contour as shown in Figures through 9 represents a different property that can be varied depending on the level of Viton Curative No. (horizontal axis) and Viton Curative No. (vertical axis).

3 Trends shown in Figures through 9 can be described as follows: Figure No. Variable Property Effect ODR at 77 C ( F) t s t s, which is a measure of processing safety, is very dependent on the level of Viton Curative No. and decreases with increasing levels of Curative No.. The level of Viton Curative No. has very little effect. ODR at 77 C ( F) M c9 M c9 is a measure of state of cure and is much more dependent on the level of Viton Curative No. than Viton Curative No.. Increasing amounts of Viton Curative No. produce a higher state of cure. ODR at 77 C ( F) t c 9 t c 9 gives a relative idea of cure time. It is very dependent on the level of Viton Curative No.. % Modulus Modulus is much more dependent on the concentration of Viton Curative No. than No.. Of particular interest is the wide range of modulus values that can be obtained with varying levels of Viton Curative No.. Elongation at Break As would be expected, elongation goes along with modulus and can be varied considerably with the level of Viton Curative No.. Hardness Hardness can be varied over about a -point range depending on the level of Viton Curative No.. 7 Compression Set, Compression set is very dependent on the level of Viton 7 hr at C (7 F) Curative No. and can have a wide range. The compression 8 Compression Set, set resistance of any given formulation can be improved with 7 hr at C (9 F) increased levels of Viton Curative No. but, of course, this 9 Compression Set, will also result in somewhat higher modulus (Figure ) and hr at C (9 F) lower elongation (Figure ). In general, for all the Viton fluoroelastomer polymers tested with combinations of Viton Curative No. and Viton Curative No., cure rate and processing safety are very dependent on the level of Viton Curative No., whereas vulcanizate properties are much more dependent on the level of Viton Curative No..

4 Table Viton Curative No. and No. in Viton E- Compound -A -B -C -D -E -F -G -H Viton E- High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No Viton Curative No Mooney Scorch (MS) at C ( F) Minimum Value unit rise, min pt pt pt pt in min in min in min in min -unit rise, min 9 7 ODR at 9 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min >. M c9, N m (in lb). (7.).7 (.). (9.). (7.).9 (.9) t c 9, min ODR at 77 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c 9, N m (in lb). (.). (9.9). (.). (.8). (.7). (.9). (.). (9.) t c 9, min Vulcanizate Properties Cure: Press min at 77 C ( F) Oven hr at C ( F) Stress/Strain and Hardness Original % Modulus, MPa (psi). (77). (7). (). (). (). () 8. (,) 8. (,) Tensile Strength, MPa (psi). (,8). (,).7 (,7). (,77).7 (,7). (,9). (,7). (,) Elongation, % 9 Hardness, Durometer A After Oven-Aging 7 hr at 7 C (8 F) % Modulus, MPa (psi). ().9 (7). (). (). ().8 (). (9). (77) Tensile Strength, MPa (psi) 9.8 (,).7 (8) 7.8 (,) 7. (,) 9. (,) 9. (,) 9.7 (,) 9.7 (,) Elongation, % 9 8 Hardness, Durometer A Other Properties Compression Set (Method B), x.9 in (. x. mm) O-rings, % 7 hr at C (7 F) 9 7 hr at C (9 F) hr at C (9 F) hr at C ( F) 7 7

5 Effect of Viton Curative No. and No. in Viton E- General Formulation for Contours (Figures through 9) Viton E- High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No. As Shown Viton Curative No. As Shown Viton Curative No., phr Figure ODR at 77 C ( F) t s (t s.), min Viton Curative No., phr Figure ODR at 77 C ( F) M c 9 in lb, (N m) (.) (.) (.7) (.) Viton Curative No., phr Figure ODR at 77 C ( F) t c 9, min Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure % Modulus, MPa (psi) 7. (,). (9) Viton Curative No., phr Figure 7 7 hr at C (7 F).8 (7). ().8 (). () Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure 8 7 hr at C (9 F) Figure Elongation at break, % Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure Hardness, Durometer A Viton Curative No., phr Figure 9 Method B, % (O-rings) hr at C (9 F) Viton Curative No., phr

6 Table Viton Curative No. and No. in Viton E- Compound -A -B -C -D -E -F Viton E- High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No Viton Curative No Mooney Scorch (MS) at C ( F) Minimum Value unit rise, min pt pt pt pt pt in min in min in min in min in min -unit rise, min 7 ODR at 9 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c9, N m (in lb). (.8). (7.8). (7.7) t c9, min ODR at 77 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c9, N m (in lb). (.). (.). (.). (9.8).9 (.7). (8.) t c 9, min Vulcanizate Properties Cure: Press min at 77 C ( F) Oven hr at C ( F) Stress/Strain and Hardness Original % Modulus, MPa (psi). (). (). ().9 (8). (87). () Tensile Strength, MPa (psi).9 (,87). (,). (,). (,77). (,7).9 (,87) Elongation, % 7 Hardness, Durometer A After Oven-Aging 7 hr at 7 C (8 F) % Modulus, MPa (psi). (). (). ().7 (8). (77). (7) Tensile Strength, MPa (psi). (,) 7. (,7).9 (,) 9.7 (,) 9. (,7). (,7) Elongation, % 9 Hardness, Durometer A Other Properties Compression Set (Method B), x.9 in (. x. mm) O-rings, % 7 hr at C (7 F) hr at C (9 F) hr at C (9 F) hr at C ( F)

7 Effect of Viton Curative No. and No. in Viton E- General Formulation for Contours (Figures through 8) Viton E- High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No. As Shown Viton Curative No. As Shown Viton Curative No., phr Figure ODR at 77 C ( F) t s (t s.), min Viton Curative No., phr Figure ODR at 77 C ( F) M c 9 N m (in lb). (). () Viton Curative No., phr Figure ODR at 77 C ( F) t c 9, min Viton Curative No., phr Viton Curative No., phr Figure % Modulus, MPa (psi) 8 (.) (.) (.8) Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure Elongation at break, % Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure Hardness, Durometer A 7 7 Viton Curative No., phr Viton Curative No., phr Figure 7 hr at C (7 F) Viton Curative No., phr Figure 7 7 hr at C (9 F) Viton Curative No., phr Figure 8 hr at C (9 F) 7 Viton Curative No., phr Viton Curative No., phr 7 Viton Curative No., phr

8 Table Viton Curative No. and No. in Viton A-HV Compound -A -B -C -D -E -F Viton A-HV High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No Viton Curative No Mooney Scorch (MS) at C ( F) Minimum Value unit rise, min 8 8 pt in min -unit rise, min pt in min ODR at 9 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c 9, N m (in lb).7 (.).9 (.). (9.). (7.9). (.) t c 9, min Min to. N m ( in lb)..... ODR at 77 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c9, N m (in lb). (7.). (.).7 (.8).9 (.7). (.). (9.9) t c 9, min Min to. N m ( in lb) Vulcanizate Properties Cure: Press min at 77 C ( F) Oven hr at C ( F) Stress/Strain and Hardness Original % Modulus, MPa (psi).7 (7). ().8 (). (87) 8. (,7) 8. (,) Tensile Strength, MPa (psi). (,). (,97).8 (,). (,).7 (,7). (,7) Elongation, % Hardness, Durometer A After Oven-Aging 7 hr at 7 C (8 F) % Modulus, MPa (psi).9 (). ().9 (). (). (8). (9) Tensile Strength, MPa (psi) 9. (,) 7. (,) 7.9 (,).7 (,). (,). (,) Elongation, % 8 8 Hardness, Durometer A Other Properties Compression Set (Method B), x.9 in (. x. mm) O-rings, % 7 hr at C (7 F) 9 7 hr at C (9 F) 8 8 hr at C (9 F) 7 hr at C ( F) 8

9 Effect of Viton Curative No. and No. in Viton A-HV General Formulation for Contours (Figures 7 through ) Viton A-HV High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No. As Shown Viton Curative No. As Shown Viton Curative No., phr Figure 9 ODR at 77 C ( F) t s (t s.), min Viton Curative No., phr Figure ODR at 77 C ( F) M c 9 N m (in lb).7 (). (). (). (). () Viton Curative No., phr Figure ODR at 77 C ( F) t c 9, min Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure % Modulus, (MPa) psi 8. (,).9 (,). (8). () Viton Curative No., phr Figure Elongation at break, % Viton Curative No., phr Figure Hardness, Durometer A Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure 7 hr at C (7 F) 8 Viton Curative No., phr Figure 7 hr at C (9 F) Viton Curative No., phr Figure 7 hr at C (9 F) Viton Curative No., phr Viton Curative No., phr 9 Viton Curative No., phr

10 Table Viton Curative No. and No. in Viton B Compound -A -B -C -D -E -F Viton B High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No Viton Curative No Mooney Scorch (MS) at C ( F) Minimum Value unit rise, min pts. pt in min in min -unit rise, min 7 pt in min ODR at 9 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c9, N m (in lb). (9.). (.). (.). (9.). (8.) t c 9, min ODR at 77 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min M c 9, N m (in lb). (.). (.). (9.). (.). (8.). (.) t c 9, min Vulcanizate Properties Cure: Press min at 77 C ( F) Oven hr at C ( F) Stress/Strain and Hardness Original % Modulus, MPa (psi).7 (97).7 (7).7 (7) 8. (,) 8. (,). (9) Tensile Strength, MPa (psi). (,97). (,). (,).7 (,7). (,9). (,) Elongation 8 8 Hardness, Durometer A After Oven-Aging 7 hr at 7 C (8 F) % Modulus, MPa (psi).8 (). (7).8 (). (7).7 (8). () Tensile Strength, MPa (psi) 9. (,7) 8. (,7) 8. (,). (,). (,).9 (,7) Elongation, % Hardness, Durometer A Other Properties Compression Set (Method B), x.9 in (. x. mm) O-rings, % 7 hr at C (7 F) hr at C (9 F) 9 hr at C 9 F) hr at C ( F)

11 Effect of Viton Curative No. and No. in Viton B General Formulation for Contours (Figures through ) Viton B High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No. As Shown Viton Curative No. As Shown Viton Curative No., phr Figure 8 ODR at 77 C ( F) t s (t s.), min Viton Curative No., phr Figure 9 ODR at 77 C ( F) M c 9 N m (in lb). (). () Viton Curative No., phr Figure ODR at 77 C ( F) t c 9, min Viton Curative No., phr Figure % Modulus, MPa (psi) 8. (,) Viton Curative No., phr Figure Elongation at break, % Viton Curative No., phr Figure Hardness, Durometer A Viton Curative No., phr.9 (,). (8) Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr Figure 7 hr at C (7 F) Viton Curative No., phr Viton Curative No., phr Figure 7 hr at C (9 F) Viton Curative No., phr Viton Curative No., phr Figure hr at C (9 F) Viton Curative No., phr Viton Curative No., phr Viton Curative No., phr

12 Table Viton E-C Faster Cure Rate With Viton Curative No. Compound -A -B -C -D Viton E- High-Activity MgO MT Carbon Black Calcium Hydroxide Viton Curative No.... Mooney Scorch (MS) at C ( F) Minimum Value -unit rise, min pt in min -unit rise, min ODR at 77 C ( F) LS Mode -/ min, torque, N m (in lb) min, torque, N m (in lb) 9 7-/ min, torque, N m (in lb) 97 7 min, torque, N m (in lb) min, torque, N m (in lb) 8 9 min, torque, N m (in lb) 9 9 Min to. N m ( in lb)....8 ODR at 77 C ( F), Microdie, Arc (.7 Rad) t s (t s.), min..8.. M c9, N m (in lb). (.).9 (.). (.7).9 (.7) t c 9, min...8. Vulcanizate Properties Cure: Press min at 77 C ( F) Oven hr at C ( F) Stress/Strain and Hardness Original % Modulus, MPa (psi). (7). (7). (7). (7) Tensile Strength, MPa (psi).8 (,8). (,8).9 (,87). (,8) Elongation, % 8 9 Hardness, durometer A Other Properties Compression Set (Method B), x.9 in (. x. mm) O-rings, % 7 hr at C (7 F) hr at C (9 F) hr at C (9 F) hr at C ( F) 8

13 Test Procedures Property Measured Test Procedure Compression Set ASTM D9-8, Method B (% deflection) Low Temperature ASTM D9-87, Method B (% deflection) Compression Set, O-Rings ASTM D-78 (87) Hardness ASTM D-87, Durometer A Mooney Scorch ASTM D-87, using the small rotor Minimum viscosity and time to a -, -, or a -unit rise are reported. Mooney Viscosity ASTM -87, ten pass C ( F), C ( F) ODR (Vulcanization measured with an oscillating disk cure meter) ASTM D8 Property Change After Oven Heat-Aging ASTM D7-88 Stress/Strain Properties % Modulus ASTM D-87, pulled at 8. mm/s ( in/min) Tensile Strength Elongation at Break Stiffness, Torsional, Clash-Berg ASTM D-87 Temperature Retraction ASTM D9-88 Volume Change in Fluids ASTM D7-79 Note: Test temperature is C (7 F) except where specified otherwise.