78. N-Nitrosamines in Technical Rubber Article Production

1999 ◽  
Author(s):  
D. Breuer
Keyword(s):  
Rubber Article

Coactivation of Delayed-Action Vulcanization. Part I. Polymeric, Nonmigratory Cure Coactivators for Accelerated Sulfur Vulcanization

1989 ◽  
Vol 62 (5) ◽  
pp. 957-972
Author(s):  
A. Y. Coran ◽  
F. Ignatz-Hoover ◽  
L. H. Davis
Keyword(s):  
Molecular Weight ◽  
Minimum Loss ◽  
Synthetic Rubber ◽  
Curing Characteristics ◽  
Sulfur Vulcanization ◽  
Delayed Action ◽  
Very High ◽  
Rubber Article

Abstract Rubbery vinylpyridine-butadiene copolymers, containing 20–65% by weight of vinylpyridine monomer units, are effective coactivators of vulcanization for TBBS-accelerated sulfur-vulcanized SBR. In addition to emulsion SBR, the new co-activator has been evaluated in copositions of solution SBR, BR, NR, and various blends. The co-activator is active in all of the compositions which contain butadiene-derived synthetic rubber. This includes blends such as SBR/BR, solution-SBR/BR, SBR/NR, BR/NR, SBR/BR/NR, etc. There is little or no activity in which NR is the only polymer. The most efficacious copolymers contain between 30 and 60% 2-vinylpyridine. The incorporation of such a copolymer into an unvulcanized butadiene-derived rubber mix can give a substantial increase in the rate of crosslink formation with only a minimum loss of scorch resistance. Since the polymeric coactivators are very high in molecular weight, it can be at least tentatively concluded that they will not migrate from one component stock to another in a built-up multi-stock rubber article, either before or during vulcanization. Since the curing characteristics of a vinylpyridine-copolymer-containing TBBS-accelerated stock can be similar to those of TBBS-accelerated NR, it might be concluded that the new additives will solve some of the problems in balancing the cures of adjacent NR and SBR stocks in a multicomponent cured rubber article.

scholarly journals KAJIAN YURIDIS UNDANG-UNDANG NOMOR 18 TAHUN 2017 TENTANG PELINDUNGAN PEKERJA MIGRAN INDONESIA

GANEC SWARA ◽  
2019 ◽  
Vol 13 (2) ◽  
pp. 230
Author(s):  
LELISARI LELISARI ◽  
IMAWANTO IMAWANTO ◽  
FAHRURROZI FAHRURROZI
Keyword(s):  
Migrant Workers ◽  
Research Method ◽  
Legal Assistance ◽  
Conceptual Approach ◽  
Government Regulations ◽  
The Law ◽  
Rubber Article

   Since the enactment of Law No. 18 of 2017 concerning the Protection of Indonesian Migrant Workers (PPMI Law), there is a new term as a substitute for Indonesian Labor (for the next term TKI) to become Indonesian Migrant Workers (hereinafter referred to as PMI). By carefully reading the law governing TKI or PMI, namely Law Number 18 of 2017 concerning PPMI, it is made to correct various weaknesses in Law No. 39 of 2004, in which the main objective is to improve the law. thus TKI or PMI are increasingly protected. In fact, this law also still has some weaknesses. The research objective is to analyze weaknesses in Law No. 18 of 2017 concerning PPMI. The method used is a normative juridical research method with a statute approach and a conceptual approach. From the results of the study, there are five weaknesses in the PPMI Law, namely: There is inconsistency in implementing the rules, the PPMI Law still holds potential institutional conflicts regarding the authority of Ministries and Institutions / Non-Ministerial Bodies in the management of migrant workers protection, Articles in the PPMI Law concerning coaching and supervision also has the potential to be a rubber article because it does not elaborate on what forms of supervision and supervision should be carried out. There is no specific article that affirms the specific needs of PMI protection (especially women) who work in the domestic sector. Regulations regarding legal assistance for PMI are not regulated in detail. As a suggestion to immediately revise the PPMI Law, then it must be guarded and completed 27 regulations derived from the mandate of the PPMI Law consisting of 12 Government Regulations, 11 Ministerial Regulations, 3 Agency Regulations and 1 Presidential Regulation

Factors Influencing the T-50 Value

1941 ◽  
Vol 14 (2) ◽  
pp. 501-513
Author(s):  
E. R. Gardner
Keyword(s):  
Accurate Method ◽  
Independent Method ◽  
The State ◽  
Routine Test ◽  
Metallic Oxides ◽  
Sulfur Determination ◽  
State Of Affairs ◽  
Sulfur Containing ◽  
Rubber Article

Abstract The paramount importance of producing the correct state of cure in a rubber article is too well known to need further emphasis. In the light of this, statement, the necessity of possessing a convenient and accurate method of assessing the state of cure is obvious. Before the advent of the T-50 test, the state of cure was measured mainly by a determination of the quantity of sulfur combined with the rubber, of stress-strain properties, or of optimum resistance to aging. The determination of combined sulfur has a disadvantage which is immediately apparent; it is laborious. Also, the figure obtained includes the amount of sulfur combined with metallic oxides used as activators, and to get an accurate measure of the quantity of sulfur combined with the rubber, a second analysis must be undertaken. There is yet another disadvantage, namely, that sulfur-containing substances added to the rubber mix interfere with the determination. The determination of tensile strength, modulus, or resistance to aging cannot be regarded as suitable for giving an accurate measure of cure, and are probably best looked on as complementary to the sulfur determination. With this state of affairs existing, it was only to be expected that, on the introduction of an entirely new and independent method of testing the state of cure, far-reaching claims should have been made, and also that the discovery should have been hailed as the elixir for all cure-testing ills. The present work was undertaken with a view to testing the validity of the claims put forward and to investigating, prior to the introduction of the T-50 as a routine test, the effect of variables likely to be encountered.

Microencapsulated Antidegradants for Extending Rubber Lifetime

1992 ◽  
Vol 65 (1) ◽  
pp. 201-210 ◽  
Author(s):  
Larry R. Evans ◽  
David A. Benko ◽  
James G. Gillick ◽  
Walter H. Waddell
Keyword(s):  
Cellulose Acetate ◽  
Migration Rate ◽  
Wall Material ◽  
Drying Process ◽  
Capsule Wall ◽  
Rubber Compounds ◽  
Process Studies ◽  
Lifetime Testing ◽  
Processing Properties ◽  
Rubber Article

Abstract Microcapsules containing rubber antidegradants were formed in a spray-drying process. Studies were carried out to select the proper wall material based on the processing properties, migration rate of the antidegradant through the capsule wall, thickness of the capsule wall, and overall capsule diameter. The resulting capsules were incorporated into a rubber article, providing a reservoir of antidegradant during the exposure lifetime. Testing of the rubber compounds with microcapsules having diameters less than 50 µm containing AN-(l,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine in a matrix of cellulose acetate showed a significant increase in the crack-free lifetime of the rubber when flexed in exposure to ozone.

Preliminary Study on Curing of Thick Rubber Article

2015 ◽  
Vol 1134 ◽  
pp. 23-27
Author(s):  
Siti Zulaikha Ibrahim ◽  
Che Mohd Som Said ◽  
Mohamad Asri Ahmad ◽  
Azemi Samsuri
Keyword(s):  
Tensile Strength ◽  
Temperature Region ◽  
The State ◽  
Curing Temperature ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Cure Time ◽  
Zinc Diethyldithiocarbamate ◽  
Preliminary Study ◽  
Rubber Article

In this study, several batches of natural rubber (SMR L) were compounded with three different types of accelerators, which were N-cyclohexylbenzothiazole-2-sulphenamide (CBS), diphenylguanidine (DPG) and zinc diethyldithiocarbamate (ZDEC). ZDEC is known as an ultrafast accelerator. The rubber compounds were cured at 140°C, 130°C, 120°C, 110°C and 100°C in accordance with the temperature gradients observed within the thick rubber block. The main aim of this study is to cure the rubber at each temperature region to the same cure time as that of the outermost region (20 minutes at 140°C). The amount of sulfur and accelerator were adjusted accordingly at each curing temperature to match the state of cure at 140°C. The state of cure of of the vulcanized rubbers were measured using hardness and tensile strength. The same state of cure is achieved if the hardness and tensile strength value are within ±2 IRHD and ±3 MPa, respectively with that of the control vulcanized rubber (hardness and tensile strength cured at 140°C). The results shows that the hardness and tensile strength of the vulcanized rubber at each temperature region are within the expected margins. The results clearly indicated that the type and amount of accelerators, and the amount of sulfur were correctly chosen at each temperature.

The Action of Ozone in the Phenomenon of the Cracking of Rubber Subjected to Repeated Mechanical Stresses

1940 ◽  
Vol 13 (3) ◽  
pp. 566-575
Author(s):  
Silvio Eccher
Keyword(s):  
Mechanical Stresses ◽  
Sudden Increase ◽  
Static Tension ◽  
Minimum Value ◽  
Rubber Belt ◽  
Complete Revolution ◽  
Shoe Soles ◽  
Rubber Article

Abstract Various rubber articles are subjected in ordinary service to repeated stretching, compression and cutting and to combinations of such forces. Repeated flexing is frequently encountered also. All these forces cause repeated changes, either positive or negative, in the dimensions of the outside surface of the rubber article. Among the important rubber products which undergo such stresses are tires, belts and shoe soles. The stresses to which the tread of a tire is subjected are certainly complex and variable. In this particular case, there are, in addition to the initial static tension, forces of compression, flexing and torsion. A rubber belt offers a simpler problem, for in this case it is possible to distinguish the following cycle of changes on the outside surface: a constant elongation in the taut section of the belt; a sudden increase in elongation on passing over the driving pulley, during which time a constant flexing stress (which depends on the curvature of the pulley) must be added to the tension on the belt; a decreased elongation along the surface of the belt in contact with the pulley; and finally a rapid return to the minimum value existing in the belt when under no tension. An analogous cycle of changes takes place at the driven pulley. Each element of the surface of a belt undergoes, therefore, during each complete revolution, two periods of tension, between which the element is alternately in the taut and in the slack section of the belt.

OPTIMIZATION OF THE VULCANIZATION PROCESS OF A THICK RUBBER ARTICLE USING AN ADVANCED COMPUTER SIMULATION TECHNIQUE

2012 ◽  
Vol 85 (4) ◽  
pp. 576-589 ◽  
Author(s):  
M. H. R. Ghoreishy ◽  
M. Rafei ◽  
G. Naderi
Keyword(s):  
Computer Simulation ◽  
Calculated Data ◽  
Simulation Technique ◽  
Measured Temperature ◽  
Computer Simulation Technique ◽  
Kinetics Of ◽  
Vulcanization Process ◽  
Rubber Article ◽  
Advanced Computer ◽  
Measured Hardness

ABSTRACT A previously developed computer simulation technique was extended for the optimization of the molding time of a thick rubber article in which a commercial finite element code was employed in conjunction with an in-house developed subroutine. The kinetics of the rubber-curing reaction and the physical and thermal properties of the materials were determined using appropriate methods. The accuracy of the method was examined by comparison of the measured temperature profile with calculated data. Two cure simulations were carried out. First, the molding time was set to the actual time used in the manufacturing specification. Having checked the distribution of the state of the cure at the center of the rubber, the molding time was reduced to save time, reduce energy, and avoid the risk of overcure at the rubber surfaces. Based on the proposed molding time, a second simulation was performed. A comparison between the hardness of the rubber article made by the reduced molding time and the measured hardness on the article manufactured by the previous molding time showed that there was 5 shore A increase in the hardness, which confirmed the applicability of procedures used in this work.

Diffusion of Curatives. I

1982 ◽  
Vol 55 (5) ◽  
pp. 1482-1498 ◽  
Author(s):  
D. A. Lederer ◽  
K. E. Kear ◽  
G. H. Kuhls
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Test Procedure ◽  
Mathematical Techniques ◽  
Increasing Temperature ◽  
Storage Temperatures ◽  
Rubber Article ◽  
Diffusion Profiles

Abstract Curatives will readily migrate across a rubber-to-rubber interface following the classical laws of diffusion. The rate of diffusion increases with increasing temperature. The absolute change in curative concentration diminishes with increasing distance from the interface and increases with time. A test procedure using conventional analytical methods can be used to accurately determine the diffusion coefficients of curatives at various storage temperatures in standard rubber formulations. Diffusion profiles and coefficients are dependent on the curative type. There appears to be a general correlation with molecular weight, with the rate of diffusion decreasing with increasing molecular weight. There is a small, rationalizable effect of concentration on the diffusion coefficient. The diffusion of curatives can cause a significant change in the cure system at or near the interface of a plied rubber article. Diffusion profiles for a particular rubber formulation can be predicted from experimental data using relatively simple analytical and mathematical techniques.

An improved Air-pump for Use in the Preservation of Larvae

1935 ◽  
Vol 26 (3) ◽  
pp. 355-356
Author(s):  
N. C. E. Miller
Keyword(s):  
Rapid Deterioration ◽  
The Tropics ◽  
Rubber Article

The air-pump which is described in the present paper was designed in order to replace the rubber double-bellows type of inflator supplied with apparatus for use in the preservation of larvae. In the tropics, the life of articles manufactured from rubber is a comparatively short one, since rubber perishes if frequently handled, or even if stored, in spite of being packed in French chalk. The only rubber article necessary for use with this pump is tubing, which is easily replaceable. In Malaya, it has been found that the double-bellows type of inflator is unsatisfactory, owing to its rapid deterioration.

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