PILGARD PVI
  • Overview
  • Compounding Information
  • Application

Chemical Name

N-(cyclohexylthio) phthalimide.  (CTP)

Chemical Structure

CAS Reg. No.

17796-82-6

Mol. Wt.

261

Product Specification

Parameter

Limits

Test Method

Product form

Powder DS (Crystalline) 

-

Color

Off White to Light Tan

-

Assay (GC)  ,% (min)

95.0

NOCIL 04-3-08

Melting Point (Initial), °C (min)

87.0

D 1519

Melting Point (Final), °C (min)

89.0

D 1519

Heat Loss, % (max)

0.30

D 4571

Ash, % (max)

0.30

D 4574

Toluene Insoluble, % (max)

0.30

NOCIL 04-3-04

Residue on 10 mesh sieve, % (max)

Nil

D 4570

Residue on 20 mesh sieve, % (max)

3.0

D 4570

Dedusting Agent, % (Max)

0.5 - 1.5

NOCIL 04-03-08

Typical Data

Specific gravity at  25°C

1.33

D 1817

Bulk density , kg/m3

520 - 560

NOCIL G-44

Bulk density (Comp), kg/m3

710 - 750

NOCIL G-44

Product Information

Solubility

Soluble in acetone and alcohol. Insoluble in water.

Classification

Pre Vulcanization Inhibitor.

Discoloration & Staining

Non-staining and Non-discoloring.

FDA Approval Status

Regulated for use in articles in contact with food under BgVV  XXI, Category 4.  Not regulated for use in FDA food contact applications.

Toxicity Data
(Please refer to the latest
Toxicological information.)

Slightly toxic. (Oral LD50 rat: over 2600 mg/kg).  May cause slight skin or eye irritation and allergic skin reaction. Inhalation of odor may cause nausea.

Handling & Personal Protection

Avoid contact with eyes, skin and clothing. Avoid  breathing vapor or dust and ensure good ventilation. In case of eye / skin contacts wash with clean water for 10 to 15 minutes. If odor is inhaled excessively, remove the person to fresh air and remove contaminated clothing.

Storage

Always store in a cool (below 35ºC) & dry place in single stack pallets away from direct sun light or any other heat source to avoid grit formation.

Packaging

Paper Bag

20 kg

FIBC

500 kg

Storage Life

12 months when stored as stated above.

Color code

None

Pilgard PVI is an ideal pre vulcanization (scorch) inhibitor for NR, IR, NR-BR blend, SBR, NR-SBR, SBR-BR blends, NBR, CR and other diene rubber based accelerated sulphur cured compounds. Only very small dosages (e.g. 0.05-0.15 phr) can improve the scorch safety of NR based sulphenamide accelerated rubber compound by 30% without affecting the rate or state of cure. Pilgard PVI does not deactivate PPD class antidegradants and eliminates porosity problems associated with the use of common acid retarders.
 

Pilgard PVI is an effective scorch inhibitor with almost all types of accelerators and in all types of sulphur cured diene rubber based compounds. Pilgard PVI offers linear and predictable response and is most sensitive to sulphenamide accelerated stocks and highly unsaturated rubbers. An approximate order of response offered by Pilgard PVI to various rubbers is as follows:
 

NR > NBR > SBR > EPDM > Butyl (IIR) > Polychloroprene (CR)
 

Pilgard PVI can be used effectively in compounds based on NBR/PVC blends, polyacrylic rubbers and sulphur cured polyurethanes.
 

Pilgard PVI is most effective at sulphur dosages between 1.5-3.0 phr. At lower dosages of sulphur, the response offered by Pilgard PVI depends on the type of accelerator used whereas at very high dosages of sulphur levels (e.g. ebonites) the response offered by Pilgard PVI is comparatively poor. Pilgard PVI is not effective with organic peroxide, PF resin and metal oxide cures.
 

It is very important to determine the accurate dosage of Pilgard PVI required for producing the desired level of scorch delay under factory operating conditions for each rubber compound. This dosage can be finalized by conducting laboratory experiments followed by factory trials and evaluation of the compound for scorch safety as well as other vulcanizate properties. Fine adjustments in the dosages of Pilgard PVI should be carried out to achieve the desired minimum scorch delay and excess dosage of Pilgard PVI (than the minimum required to prevent scorch) should be avoided. This is necessary since excess dosage of Pilgard PVI can delay the cure time / render the product under cured which can affect vulcanizate properties such as state of cure, resilience, compression set, etc.
 

Pilgard PVI does not cause any detrimental effect on the vulcanizate properties such as tensile strength, modulus values, and resilience / heat build up, compression set or permanent set, ozone resistance and hot air aged vulcanizate properties when used at optimum dosage. Pilgard PVI does not cause contact or migration staining but can slightly discolor bright white rubber products. When very high dosages of Pilgard PVI are used (e.g. over 0.4 phr), phthalimide bloom may appear on the surface and also slight reduction in the state of cure and related properties may be experienced. The state of cure can be adjusted by a very small (e.g. 0.07-0.1 phr) increase in accelerator or sulphur dosage. The phthalimide bloom is water soluble and can easily be washed.
 

Pilgard PVI is an effective tool to overcome various processing limitations.
For example:

  • Incorporation of Pilgard PVI can permit addition of curatives at an early stage of mixing for better dispersion of  curatives, reduced mixing cycle time, reduced power consumption, reduced labor and capital investment costs.
  • Permit use of higher processing speeds and temperatures during mixing, calendaring, extrusion, etc. for increased productivity and reduced processing cost,
  • Permit use of higher injection temperatures and shorter cure cycles for increased productivity.
  • Permit recovery of rubber compounds with marginal processing safety and recovery of partially scorched compound for scrap elimination.
  • Improve the storage stability of fully compounded stocks at ambient temperatures (particularly the fast curing compounds).
     

Pilgard PVI is generally incorporated along with accelerators and sulphur during internal mixing / mill mixing of the stocks. In case of fast curing / rework stocks; Pilgard PVI is added on cool mill.

Pilgard PVI is widely used in the manufacture of almost all rubber products based on sulphur curable rubbers. Pilgard PVI is not used in latex compounding and the rubber products intended for contact with food/drugs.
 

TYPICAL DOSAGES:

Typical dosages of Pilgard PVI required to produce the desired scorch delay depend on the type of rubber, loadings of reinforcing fillers, selection of accelerator type and dosage, sulphur dosage, etc. used in the compounding formulations and the processing operations required to be performed for the product manufacture under the existing processing conditions. Also as stated earlier, Pilgard PVI dosages have to be fine tuned to achieve only the desired level of processing safety and mould flow time and excess dosages of Pilgard PVI have to be avoided. Ambient temperatures, process water temperatures and modifications in processing machinery with respect to processing temperatures or speeds can influence Pilgard PVI dosages considerably.

Given below are the typical dosages of Pilgard PVI for various products.
 

 TYPICAL DOSAGES OF PILGARD PVI

Products

Rubber

Accelerator / Pilgard PVI / S, phr

Primary
Accelerator

Secondary
Accelerator

Pilgard PVI

S

Truck & Bus Treads
Bias
Radial
Cap
Base
Truck Sidewall
Truck Carcass
Steel cord skim


NR
NR-BR
NR-BR
NR
NR-BR
NR
NR


MOR: 0.5-0.7
MOR: 1.1-1.5
MOR: 1.3-1.5
MOR: 0.5-0.7
MOR: 0.8-1.0
MOR: 0.7-0.8
DCBS: 2.0   


-
-
-
-
-
-
TMTM: 0.1-0.12


0.10-0.15
0.10-0.20
0.10-0.20
0.10-0.15
0.10-0.15
0.10-0.20
0.10-0.15


2.3-2.7
1.2-1.5
1.2-1.5
2.2-2.5
2.0-2.2
Insol S: 2.5
Insol S: 4.5

Passenger Tyre Treads

Passenger Tyre Sidewall
Passenger Tyre Carcass

NR-BR
SBR-BR
NR-SBR
NR

CBS: 1.2
CBS: 1.5
CBS: 1.3
CBS: 1.0-1.2

TMTM: 0.10
TMTM: 0.20
TMTM: 0.10-0.15
TMTM: 0 - 0.10

0.10-0.15
0.10-0.15
0.10-0.15
0.10-0.20

2.0
1.8
1.8
Insol S: 2.2

Cycle Tyre Treads

Cycle Tyre Carcass

NR-RR
NR-BR
NR

CBS: 1.0
CBS: 1.2
CBS: 1.0

TMTD: 0.10-0.15
TMTD: 0.10-0.15
TMTD: 0.20-0.25

0.10-0.20
0.10-0.15
0.15-0.20

2.4
2.0
2.5

Retreads
Hot Cure

Precured

 

NR
NR-BR
NR-BR

 

MOR: 0.5
MOR: 0.8-1.0
MOR: 1.0-1.2

 

-
-
-

 

0.10-0.15
0.10-0.15
0  - 0.10

 

Insol S: 2.5
Insol S: 2.0
1.5-1.7

Conveyor Belt Cover
General purpose
Heat Resistant

 

NR
NR-SBR

 

MOR: 0.8
CBS: 1.2-1.4

 

MBTS: 0.2
-

 

0.10-0.20
0.15-0.20

 

2.2-2.4
1.5

V Belts
Base
Cushion
Friction

 

NR
NR
NR

 

CBS: 0.6-0.8
CBS: 0.7-0.8
CBS: 0.7-0.8

 

MBTS: 0.2
MBTS: 0.3
-

 

0.10-0.20
0.10-0.15
0.10-0.15

 

3.0
2.4
2.6

Footwear
DV Soles & Molded soles
/ Heels

 

NR-SBR

 

CBS: 0.8-1.0

 

TMTD: 0.10-0.20

 

0.10-0.15

 

2.0-2.2

Hoses
Tube

Cover

 

NR-SBR
NBR
NR

 

CBS: 0.7-1.0
CBS: 1.0-1.2
CBS: 0.7-1.0

 

MBTS: 0.3
TMTD: 0.10-0.20
TMTD:  0.0-0.20

 

0.15-0.20
0.15-0.20
0.15-0.20

 

2.0-2.4
1.5
2.2-2.5

Cables

NR

CBS: 1.0

TMTD: 0.3

0.10-0.20

1.2-1.3

Injection Moldings

NR

CBS: 0.8

-

0.20-0.30

2.2-2.4

Misc. Molded and Extruded
Goods

NR
NR-SEV
SBR
SBR-SEV
NBR
NBR-SEV

CBS: 0.7
CBS: 1.5
CBS: 1.2
CBS: 2.0
CBS: 1.0-1.2
CBS: 1.0

TMTD: 0.10-0.20
TMTD: 0.5
TMTD: 0.10-0.20
TMTD: 0.5
TMTD: 0.15
TMTD: 1.0

0.0-0.15
0.0-0.15
0.0-0.10
0.0-0.10
0.0-0.10
0.0-0.10

2.2
1.5
2.2
0.75
1.5
1.0

Pre Vulcanization Inhibitor
Awards / Certifications