Synthesis and property of epoxy prepolymer and curing agent with high refractive index

Abstract

An epoxy prepolymer with high refractive index, diglycidyl ether of thiodiphenol (DGETP), was synthesized by 4,4′-thiodiphenol and epichlorohydrin via a two-step method. The curing agent o-benzenedimethanethiol (OBDMT) was synthesized by thiourea method. Fourier transform infrared spectroscopy and proton nuclear magnetic resonance were employed to characterize the structures of these resins. The cured product of DGETP and OBDMT was analyzed by differential scanning calorimetry, ultraviolet–visible spectrometer, and Abbe refractometer and compared with the property of traditional curing agent of methyl hexahydrophthalic anhydride (MHHPA) and ordinary bisphenol A diglycidyl ether epoxy prepolymer cured products. The lower curing temperature and glass transition temperature of DGETP than those of MHHPA can be mainly attributed to the strong rotation capability of thioether bond. The zero light transmittance region of DGETP/OBDMT curing adhesive (200–380 nm) was broader than that of the other three. The refractive index of DGETP/OBDMT was up to 1.654.

Keywords

LED epoxy prepolymer curing agent high refractive index thiol

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References

Rector

Starkey

. Performance of epoxy encapsulants for optoelectronic packaging. In: 4th IEEE international conference on polymers and adhesives in microelectronics and photoics. Portland, USA, 12–15 September 2004, pp. 211–221.

Gunshor

Nurmikkob

. Wide bandgap semiconductors and their application to light emitting devices.Curr Opin Solid State Mater Sci 1996; 1: 4–10.

Huang

Chu

Wei

. Comparison of epoxy resins for applications in light-emitting diodes. Adv Polym Tech 2004; 23: 298–306.

Edwards

Zhou

. Comparative properties of optically clear epoxy encapsulate. Proc SPIE 2001; 4436: 190–197.

Schubert

. Light-emitting diodes. 2nd ed. Cambridge, UK: Cambridge University Press, 2003.

Lin

Tran

Zhou

Shi

. Materials challenges and solutions for the packaging of high power LEDs. In: Proceedings of 2006 International Conference on Microsystems, Packaging, Assembly, Taipei, Taiwan, pp. 177–180.

Zhou

Tran

Lin

Shi Frank

. One-component, low-temperature and fast cure epoxy encapsulant with high refractive index for LED applications. IEEE Trans Adv Pack 2008; 31: 484–489.

Harumichi

Yoshinobu

. Sulfur-containing epoxy compound and sulfur-containing epoxy resin. JP10130250, Japan, 1998

Teruyuki

Koju

Tohru

. Lens comprising a resin having a large refractive index and process for preparing the lens. EP0351073A2, Japan, 1990

10.

Judek

Spiewak

. An efficient synthesis of thiobis(benzenethiol). Synthetic Commun 1998; 28: 197–199.

11.

Boer

Meng

Perepichka

Zheng

Frank

Chabal

. Synthesis and characterization of conjugated mono-and dithiol oligomers and characterization of their self-assembled monolayers. Langmuir 2003; 19: 4272–4284.

12.

Pan

Zhang

Yang

. Synthesis, characterization, and properties of novel novolac epoxy resin containing naphthalene moiety. Polymer 2007; 48: 3686–3693.

13.

Antoon

, Koening JI and Serafini T.Fourier-transform infrared study of the reversible interaction of water and a crosslinked epoxy matrix. J Polym Sci Pol Phys 1981;19: 1567–1575.