Recent Developments in Superior Processing Natural Rubber

1960 ◽  
Vol 33 (3) ◽  
pp. 810-824 ◽  
Author(s):  
H. C. Baker ◽  
R. M. Foden
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Operating Conditions ◽  
Lower Percentage ◽  
Die Swell ◽  
Rubber Compounds ◽  
Recent Developments ◽  
Efficient Processing ◽  
And Control

Abstract SP rubbers give greater latitude in extrusion and calendering processes by extending the range of operating conditions and giving greater scope for compounding for good physical properties. Compounds based on SP rubbers extrude smoothly with lower die swell at lower temperatures and higher viscosities. Greater productivity is obtained through the faster screw speeds which are possible with SP rubbers in many types of compound. SP rubber compounds calender with greater conformity to gage, greater ease of handling and control of shrinkage of the calendered sheet, at temperatures 10° C lower than normal. The firmer stocks given by SP rubbers and their greater resistance to degradation on milling lead to reduced wastage of unvulcanized compound in the factory, while the stricter control of processing permitted by SP rubbers results in a lower percentage of rejected articles. Evaluation of an experimentally produced SP 90 crepe has indicated the potentialities of a concentrated form of SP rubber as a more efficient processing aid than crosslinked SBR 1009 with NR and SBR.

A Review on Heat and Reversion Resistance Compounding

2003 ◽  
Vol 19 (3) ◽  
pp. 143-170 ◽  
Author(s):  
R. N. Datta
Keyword(s):  
Thermal Stability ◽  
Natural Rubber ◽  
Physical Properties ◽  
Dynamic Performance ◽  
Thermal Ageing ◽  
Vital Role ◽  
Performance Characteristics ◽  
Network Density ◽  
Performance Property ◽  
Rubber Compounds

When sulfur vulcanized natural rubber compounds are exposed to a thermal ageing environment significant change in physical properties and performance characteristics are observed. These changes are directly related to modifications of the original crosslink structure. Decomposition reactions tend to predominate and thus leading to reduction in crosslink density and physical properties as observed during extended cure and when using higher curing temperatures. The decrease in network density is common when vulcanizates are subject to an anaerobic ageing process. However, in the presence of oxygen, the network density is increased with the main chain modifications playing a vital role. Over the years the rubber industry has developed several compounding approaches to address the changes in crosslink structure during thermal ageing. This paper gives a review of these compounding approaches. As with many formulation changes in rubber compounding, there is a compromise that must be made when attempting to improve one performance characteristic. For example, improving the thermal stability of vulcanized natural rubber compounds by reducing the sulfur content of the crosslink through the use of the more efficient vulcanization systems will reduce dynamic performance property such as fatigue resistance. The challenge is to define a way to improve thermal stability while maintaining dynamic performance characteristics.

scholarly journals Evaluation of Cooking Oil as Processing Addtive for Natural Rubber

2017 ◽  
Vol 34 (1) ◽  
pp. 17 ◽  
Author(s):  
Y. M. SYAMIN ◽  
S. AZEMI ◽  
K. DZARAINI
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Natural Rubber ◽  
Physical Properties ◽  
Aromatic Ring ◽  
Rolling Resistance ◽  
Cooking Oil ◽  
Alternative Option ◽  
Rubber Compounds ◽  
Polycyclic Aromatic

It was reported recently that high amount of aromatic ring  or number of polycyclic aromatic hydrocarbon compounds found in aromatic oil are carcinogenic. This paper discusses the work to evaluate the Malaysian cooking oil as an alternative option to be used as process oil since cooking oil is safe to use and non-toxic. The performance of cooking oil is compared againstaromatic and paraffinioils. The results showed that rubber compounds containing cooking oil produced almostsimilar cure characteristicsas those produced by aromatic and paraffinioils indicating that it did not interfere with the vulcanization reaction. The physical properties of the vulcanizates containing cooking oil were almostsimilar to those of vulcanizates containing aromatic and paraffinioils, except the rebound resilience. The vulcanizates containing cooking oil gave higher resilience than vulcanizates containing aromatic and paraffinioils. High resilience is one of the desired features for a low rolling resistance tyre. Cooking oil provided this extra advantage.

Natural Rubber Compounds for Intermittent Low Temperature Service

1957 ◽  
Vol 30 (2) ◽  
pp. 652-666
Author(s):  
W. P. Fletcher ◽  
A. N. Gent ◽  
R. I. Wood
Keyword(s):  
Transition Temperature ◽  
Low Temperature ◽  
Natural Rubber ◽  
Physical Properties ◽  
Dynamic Stiffness ◽  
Theoretical Treatment ◽  
Rubber Compounds ◽  
Second Order Transition ◽  
General Physical ◽  
Silicone Rubbers

Abstract The changes in physical properties of rubber vulcanizates on approaching the so-called second order transition temperature are discussed and distinction is drawn between these phenomena and those associated with crystallization. A simple apparatus of the torsional pendulum type is used to determine the dynamic stiffness and hysteresis loss factor at a frequency of about 0.5 c.p.s. of vulcanizates in the temperature range 20 to −120° C. A large number of liquids are examined as potential plasticizers for lowering the rubber to glass transition temperature and a number are shown to have a high order of efficiency in this respect. Of these materials some also conform to the overriding requirements of low volatility and adequate compatibility with rubber. The loss in physical properties consequent on increase of plasticizer content is not markedly different for most of the plasticizers. Di-iso-octyl adipate is representative of the liquids which give useful low temperature plasticization and a number of commercial type compounds are developed using this plasticizer with carbon black or silica reinforcement, some of these have transition temperatures approaching those of the silicone rubbers but with a better level of general physical properties. A tentative theoretical treatment for the low temperature plasticization of nonpolar rubbers is discussed and this leads to a law which has been found to predict fairly well the transition temperature of a plasticized natural rubber compound in terms of the index of variation with temperature of the plasticizer viscosity.

Influence of Processing Oil Based on Modified Epoxidized Vegetable Oil with N-Phenyl-p-Phenylenediamine (PPD) on Extrusion Process Behaviors of Natural Rubber Compounds

2015 ◽  
Vol 659 ◽  
pp. 423-427 ◽  
Author(s):  
Chalida Moojea-Te ◽  
Adisai Rungvichaniwat ◽  
Kannika Sahakaro
Keyword(s):  
Natural Rubber ◽  
Heat Generation ◽  
Extrusion Process ◽  
Die Swell ◽  
Rubber Compound ◽  
Output Rate ◽  
Extrusion Rate ◽  
Rubber Compounds ◽  
Filler Dispersion ◽  
Mooney Viscosity

Rubber processing oil based on modified epoxidized vegetable oils (m-EVO) was prepared by a reaction of epoxidized palm oil EPO) or epoxidized soybean oil (ESBO) with N-Phenyl-ρ-phenylenediamine (PPD) at a mole ratio of 1:0.5. The comparison of m-EVO with aromatic oil (Treated distillate aromatic extract, TDAE) on extrusion process behaviors (output rate, extrusion rate, screw efficiency, heat generation, die swell, extrudate appearance) of carbon black (N330) filled natural rubber (NR) compound was made. It was found that the mooney viscosity of m-EVO based natural rubber compounds are slightly higher than that of the TDAE based natural rubber compound (ML(1+4)100°C: m-ESBO 65.5±0.7; m-EPO 59.7±0.2; TDAE 56.5±1.0), which probably due to the poorer filler dispersion in the compounds. The extrusion process behaviors for output rate (g/min: m-ESBO 191.0±0.6; m-EPO 191.2±0.4; TDAE 195.5±0.6), extrusion rate (cm3/min: m-ESBO 179.6±0.6; m-EPO 183.2±0.4; TDAE 186.4±0.6) and screw efficiency (%: m-ESBO 30.8±0.6; m-EPO 31.4±0.4; TDAE 32.0±0.6). All the three compounds show similar extrusion process behaviors in which the TDAE based compounds shows a marginal higher values than the m-EVO as its lower mooney viscosity lead to a better flow. The m-EPO and m-ESBO based natural rubber compounds show very similar extrusion process behaviors. The heat generation (°C: m-ESBO 61.0±0.8; m-EPO 62.1±0.4; TDAE 63.1±1.0) and die swell (%: m-ESBO 11.0±0.7; m-EPO 11.0±0.5; TDAE 12.7±0.3) of the m-EVO based natural rubber compounds are slightly lower than those of the TDAE based natural rubber compound. As there are no significant differences in the extrusion process behaviors, with respect to extrusion process, m-EVO can be used to replace TDAE oil.

Heat Resistance of Neoprene-GN Vulcanizates

1944 ◽  
Vol 17 (1) ◽  
pp. 173-184
Author(s):  
D. B. Forman
Keyword(s):  
Natural Rubber ◽  
Heat Resistance ◽  
Physical Properties ◽  
High Temperatures ◽  
Continuous Exposure ◽  
Oxygen Bomb ◽  
Rubber Compounds ◽  
Active Subject ◽  
Continuous Problem

Abstract Control of heat deterioration is a continuous problem for the chemist. In the case of rubber and synthetic elastomers, the rubber chemist has charted the changes in the physical properties of vulcanized elastomers during heat aging. He has developed many methods for retarding the deterioration of rubber compounds by heat; but with the newer synthetic elastomers the development of methods of retarding deterioration by heat is now an active subject of investigation. The degree of deterioration depends on the methods of compounding and curing the different elastomers, as well as on the conditions of aging. In general, continuous exposure to high temperatures softens natural rubber but hardens synthetic elastomers. Inherently Neoprene has greater heat resistance than natural rubber. Many investigators have described the heat resistance of rubber vulcanizates, but only a few have reported on the heat resistance of Neoprene vulcanizates, and these reports have been primarily comparisons of given Neoprene vulcanizates with one or more rubber stocks. The compounding of Neoprene (Type GN) for heat resistance was discussed by Catton, Fraser, and Forman. The oxygen bomb aging of Neoprene (Types E and GN) was compared with that of various rubber compositions by Neal, Bimmerman, and Vincent.

Cure Characteristics and Ageing Resistance of Recovered Waste Pre-Vulcanized Nitrile/Epoxidized Natural Rubber Latex Blends in Nitrile Butadiene Rubber Compounds

2015 ◽  
Vol 1119 ◽  
pp. 347-351
Author(s):  
A.I.H. Dayang Habibah ◽  
V. Devaraj ◽  
H. Kamarularifin ◽  
Ibrahim Suhawati
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Natural Rubber Latex ◽  
Butadiene Rubber ◽  
Rubber Latex ◽  
Maximum Torque ◽  
Rubber Compounds ◽  
Curing Characteristics ◽  
Control Compound ◽  
Minimum Torque

Waste pre-vulcanized nitrile latex (WPNL), obtained from nitrile glove dipping tank was blended at different ratios with concentrated ENR latex processed via ultrafiltration and designated as ENRLC-SP20 and ENRLC-SP50, respectively, with the number indicating, the percentage of WPNL incorporated into the blend. The blends were prepared in the latex stage and subsequently processed into dry rubber. The rubbers were then blended with virgin nitrile rubber (NBR) at various ratios and the curing characteristics and physical properties of the blends were evaluated. The results showed the maximum torque (MH) decreases while the minimum torque (ML) increases with increasing level of SP 50 rubber. Using higher concentrations of SP-50, the results showed slight reductions in the cure (t90) and scorch time (ts2), respectively. It was also found that by increasing ratio of ENRLC-SP20 and ENRLC-SP50 improves the heat ageing resistance of NBR blends at 100°C as evidenced by the higher percentages in retention of the blends, compared to the control compound.

scholarly journals COMPARATION OF RUBBER MILLING PROCESS TO PRODUCE NATURAL RUBBER COUMPOUNDS USING MODIFIED AND UNMODIFIED LOCAL CLAY FILLER

2020 ◽  
Vol 21 (2) ◽  
pp. 69
Author(s):  
Abu Hasan ◽  
Martha Aznury ◽  
Indah Purnamasari ◽  
Muhammad Zaman ◽  
Robert Junaidi ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Milling Process ◽  
Rubber Compound ◽  
Local Clay ◽  
Modified Clay ◽  
Rubber Compounds ◽  
Curing Characteristics ◽  
Peg 4000 ◽  
Better Than

COMPARISON OF RUBBER MILLING PROCESS TO PRODUCE NATURAL RUBBER COMPOUNDS USING MODIFIED AND UNMODIFIED LOCAL CLAY FILLER. Many researchers have studied the effect of modified clay as filler on rubber compounds for both natural rubber and synthetic rubber. Various chemicals are used as clay modifiers. In the rubber milling process, modified clay is directly used as filler after pretreatment with clay modifier. However, clay modifiers can also be milled together with original clay during the rubber mastication and milling process. Thus both of these methods certainly produce different physical properties, so the comparison of the two rubber milling processes is the focus of this research. The analysis of the curing characteristics and physical properties of vulcanized natural rubber was carried out with a rheometer and physical properties test units. Thermal analysis was carried out using TG/DTA and dispersion of filler on the rubber compound was analyzed by SEM. The results of the curing characteristic of the rubber compound and the physical properties of vulcanization showed that there was an effect due to the comparison of the rubber milling process. Modified clay using JH-S69 is better than JH-S69 milled with original clay and vice versa occurs in PEG 4000 which is used as clay modifier. PEG 4000 which is milled together with original clay produces curing characteristic and physical properties of vulcanization better than pretreatment of clay to be modified clay. This analysis is in line with the analysis using SEM.

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