• Title, Summary, Keyword: Cure System

Search Result 419, Processing Time 0.035 seconds

Binary Cure Systems of 1,6-Bis(N,N'-dibenzylthiocarbamoyldithio)-hexane and Benzothiazole Sulfenamides in Carbon Black-filled Natural Rubber Compounds

  • Choi, Sung-Seen;Park, Byung-Ho;Lee, Seung-Goo;Kim, Beom-Tae
    • Bulletin of the Korean Chemical Society
    • /
    • v.23 no.2
    • /
    • pp.320-324
    • /
    • 2002
  • Binary cure system is composed of different two cure accelerators, which can cause a synergy effect to delay the scorch time and to increase the cure rate. In this study, binary cure systems between 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)-hexane (DBTH) and benzothiazole sulfenamides were investigated using carbon black-filled natural rubber compounds. N-Cyclohexyl-2-benzothiazole sulfenamide (CBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), and 2-(morpholinothio) benzothiazole (MOR) were employed as benzothiazole sulfenamides. The binary cure systems show scorch safty at high temperature. The binary cure systems have faster cure rate and better reversion resistance than the single cure system of the benzothiazole sulfenamides. DBTH is found to be more effective to decrease the viscosity of a compound than the benzothiazole sulfenamides. Physical properties of the vulcanizates with the binary cure system are better than those of the vulcanizates with the single one.

Studies on the Crosslinking Density and Reinforcement of Rubber Compounds by Cure System (가황조건별 배합고무의 가교밀도와 고무보강성에 관한 연구)

  • Park, Nam-Cook;Lee, Seog
    • Elastomers and Composites
    • /
    • v.33 no.5
    • /
    • pp.315-323
    • /
    • 1998
  • The purpose of this study was to investigate the crosslinking density and reinforcement of rubber compounds with various carbon black loadings, cure systems and cure temperatures. Bound rubber content increased with volume fraction of carbon black in rubber compounds, but total crosslinking density decreased with increasing the bound rubber content. Rate constant of cure reaction was changed significantly by cure system and cure temperature, especially it showed strong dependence on the cure temperature. High activation energys of cure reaction were shown in the rubber compound with high loading of carbon black under EC system and in the rubber compound with low loading of carbon black under CC system. High total crosslinking density of vulcanized compounds appeared in the rubber compound with low loading of carbon black and CC system among cure systems. Typical change of total crosslinking density by EC system was not shown. The highest elastic constant by Mooney-Rivlin equation was shown in the rubber compound with low loading of carbon black and SEC system. Modulus increased as increasing the loading of carbon black in the rubber compounds and showed the order of SEC, CC, and EC system for cure system.

  • PDF

Expert Cure System for the Carbon Fiber Epoxy Composite Materials (탄소섬유 에폭시 복합재료 제조의 전문가시스템 연구)

  • 최진호;이대길
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.7
    • /
    • pp.1773-1782
    • /
    • 1994
  • In this paper, the expert cure system for carbon fiber epoxy composite materials, which controls the temperature and pressure of the autoclave according to the several rules, was developed to manufacture better composite products in shorter curing time. The rules were based on the on-line measured quantities such as the dielectric properties and temperature of the composites and the pressure of the autoclave. The curing time and the mechanical properties of the composite materials manufactured with the expert cure system were compared to those of the specimens manufactured with the conventional cure cycle.

The Effects of Cure System on Vulcanization Reaction Constant and Physical Properties of Rubber Compounds (가황시스템 변화가 배합고무의 가황반응속도 및 물리적 특성에 미치는 영향)

  • Lee, Seag;Park, Nam Cook
    • Applied Chemistry for Engineering
    • /
    • v.10 no.3
    • /
    • pp.419-426
    • /
    • 1999
  • In this study, the reaction rate constant, activation energy, total crosslinking density, elastic constant, cure properties ($t_5,\;t_{90}$), modulus, and abrasion resistance of rubber compounds were investigated as a function of cure temperatures, cure systems and reinforcing filler loadings. Reaction rate constants showed strong dependence on thc carbon black loading, cure temperature and cure system, and increased sharply with increasing the reaction temperatures. The lowest activation energy was obtained in the efficient cure (EC) system which corresponds to the high level of sulfur to accelerator ratio, and the activation energy was decreased with decreasing the carbon black loadings. The change of carbon black loadings directly affects the modulus and abrasion resistance, but the change of cure system showed various effects on the rubber compounds. Increased carbon black loadings showed the high modulus, improved abrasion resistance and short scorch time but decrease in crosslinking density and elastic constant. Higher crosslinking density and elastic constant were shown in the EC cure system regardless of carbon black loadings, but scorch timc ($t_5$) was not affected by the change of the ratio of sulfur to accelerator. Rapid optimum cure time ($t_{90}$) were showen in the EC cure system. Also, the equivalent cure curve coefficient of rubber compound was 0.96 for conventional cure (CC) system, and 0.94 for semi-efficient cure (SEC) and EC system regardless carbon black loadings. As regarding the abrasion resistance, wear volume showed the logarithmic increase for the loaded weight.

  • PDF

Effect on the residual stress of cure conditions in an epoxy system

  • Yu, Kyung-Bee;Seo, Sang-Ha;Kim, Young-Un;Moon, Chang-Kwon
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • /
    • pp.233-236
    • /
    • 2006
  • A dilatometer was used to investigate the effect of cure conditions and the presence of filler in an epoxy system. These studies showed shrinkage in the cured epoxy when heating it through the glass transition temperature region. The magnitude of the shrinkage, related to stress build up in the epoxy during curing, was influenced by the processing conditions, filler presence and the nature of the mold used to contain the resin. Cure and cyclic cure at a lower temperature, prior to a post cure, decreased the magnitude of observed shrinkage. Cure shrinkage decreased with number of cyclic cure. Post cured samples outside the mold led to less shrinkage compared with sample in the mold. And sample containing kaolin filler showed less shrinkage than unfilled sample.

  • PDF

Cure Konetics and Mechanism of DGEBA-MDA-Malononitrile System (Malononitrile로 개질된 DGEBA-MDA계의 경화반응 속도론 및 반응 메카니즘)

  • Im, Seong-Su;Jo, Seong-U;Yu, Hui-Yeol;Sim, Mi-Ja;Kim, Sang-Uk
    • Korean Journal of Materials Research
    • /
    • v.3 no.3
    • /
    • pp.215-222
    • /
    • 1993
  • Malononitrile(MN) as a reactive additive was added to Diglycidyl ether of bisphenol A (DGEBA)/Methylene dianiline (MDA) system in order to modify a thermosetting epoxy resin. Cure ki. netics and cure mechanism of this modified system were investigated by using DSC(differential scanning calorimetry) and FT-IR(fourier transform infrared spectrometry). Cure kinetics gave an information that the DGEBA/MDA system modified with MN should cure at over $110^{\circ}C$ after curing at about $80^{\circ}C$ for the complete curing. The activation energy of the first cure was nearly constant and that of the second cure was increased as the MN content was increased. Cure mechanism for the system was investigated with the samples cured every $30^{\circ}C$, from $80^{\circ}C$ to $170^{\circ}C$, for Ihr. It was known that the cure reactions of the epoxy-diamine system were composed of PA -E, SA - E and E-OH reactions. Beside these three reactions, in the DGEBA/MDA/MN system PA-CN and CN-OH reaction was found.

  • PDF

Cure Characteristics of Ethoxysilyl Bisphenol A Type Epoxy Resin Systems for Next Generation Semiconductor Packaging Materials (새로운 반도체 Packaging용 Ethoxysilyl Bisphenol A Type Epoxy Resin System의 경화특성 연구)

  • Kim, Whan Gun
    • Journal of the Semiconductor & Display Technology
    • /
    • v.16 no.2
    • /
    • pp.19-26
    • /
    • 2017
  • The cure properties of ethoxysilyl bisphenol A type epoxy resin (Ethoxysilyl-DGEBA) systems with different hardeners were investigated, comparing with DGEBA and Diallyl-DGEBA epoxy resin systems. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The Ethoxysilyl-DGEBA epoxy resin system showed lower cure conversion rates than DGEBA and Diallyl-DGEBA epoxy resin systems. The conversion rates of these epoxy resin systems with DDM hardener are lower than those with HF-1M hardener. It can be considered that the optimum hardener for Ethoxysilyl-DGEBA epoxy resin system is Phenol Novolac type. These lower cure conversion rates in the Ethoxysilyl-DGEBA epoxy resin systems could be explained by the retardation of reaction molecule movements according to the formation of organic-inorganic hybrid network structure by epoxy and ethoxysilyl group in Ethoxysilyl- DGEBA epoxy resin system.

  • PDF

Effect on the Residual Stress of Cure Profiles, Fillers and Mold Constraints in an Epoxy System

  • Moon, Chang-Kwon;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
    • /
    • v.23 no.4
    • /
    • pp.1-5
    • /
    • 2009
  • A dilatometer was used to investigate the effect of cure conditions, mold types and the presence of filler in an epoxy system. These studies showed shrinkage in the cured epoxy when heating it through the glass transition temperature region. The magnitude of the shrinkage, related to stress build up in the epoxy during curing, was influenced by the processing conditions, filler presence and the nature of the mold used to contain the resin. Cure and cyclic cure at a lower temperature, prior to a post cure, decreased the magnitude of observed shrinkage. Cure shrinkage decreased with the number of cyclic cures. Post cured samples outside the mold led to less shrinkage compared with samples in the mold. Sample cured in a silicon mold represented less shrinkage than sample cured in an aluminum mold. Sample containing kaolin filler showed less shrinkage than unfilled sample.