Thermal Processing of EVA Encapsulants and Effects of Formulation Additives

doi:10.1109/PVSC.1996.564359

Thermal Processing of EVA Encapsulants and Effects of Formulation Additives

Research output: Contribution to conference › Paper

Abstract

We investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films, A9918P and 15295P, andsolution-cast films of Elvax(TM) (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P(TM), used in the two commercial EVA formulations,greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of approx. 80% when cured at programmed 155 deg. C for 4minutes. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.

Original language	American English
Pages	1251-1254
Number of pages	4
DOIs	https://doi.org/10.1109/PVSC.1996.564359
State	Published - 1996
Event	Twenty Fifth IEEE Photovoltaic Specialists Conference - Washington, D.C. Duration: 13 May 1996 → 17 May 1996

Conference

Conference	Twenty Fifth IEEE Photovoltaic Specialists Conference
City	Washington, D.C.
Period	13/05/96 → 17/05/96

NREL Publication Number

NREL/CP-22519

Access to Document

10.1109/PVSC.1996.564359

Cite this

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title = "Thermal Processing of EVA Encapsulants and Effects of Formulation Additives",

abstract = "We investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films, A9918P and 15295P, andsolution-cast films of Elvax(TM) (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P(TM), used in the two commercial EVA formulations,greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of approx. 80% when cured at programmed 155 deg. C for 4minutes. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.",

author = "NREL",

year = "1996",

doi = "10.1109/PVSC.1996.564359",

language = "American English",

pages = "1251--1254",

note = "Twenty Fifth IEEE Photovoltaic Specialists Conference ; Conference date: 13-05-1996 Through 17-05-1996",

}

TY - CONF

T1 - Thermal Processing of EVA Encapsulants and Effects of Formulation Additives

AU - NREL, null

PY - 1996

Y1 - 1996

N2 - We investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films, A9918P and 15295P, andsolution-cast films of Elvax(TM) (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P(TM), used in the two commercial EVA formulations,greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of approx. 80% when cured at programmed 155 deg. C for 4minutes. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.

AB - We investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films, A9918P and 15295P, andsolution-cast films of Elvax(TM) (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P(TM), used in the two commercial EVA formulations,greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of approx. 80% when cured at programmed 155 deg. C for 4minutes. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.

U2 - 10.1109/PVSC.1996.564359

DO - 10.1109/PVSC.1996.564359

M3 - Paper

SP - 1251

EP - 1254

T2 - Twenty Fifth IEEE Photovoltaic Specialists Conference

Y2 - 13 May 1996 through 17 May 1996

ER -

Thermal Processing of EVA Encapsulants and Effects of Formulation Additives

Abstract

Conference

NREL Publication Number

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Cite this