Determining minimum curing time and temperature for a phenolic formaldehyde/epoxy adhesive
(2020) KEML10 20201Department of Chemistry
- Abstract
- Alfa Laval has been using its unique adhesive mixture for over 50 years for bonding of rubber gaskets to the corrugated plates used in their heat exchangers. The adhesive mix is designated GC6 and is composed out of an epoxy component and a phenolic component. GC6 has throughout the years shown exceptionally good performance in both adhesion to the rubber gasket and to the plate with minimal pre-treatments of the surfaces required. The manufacturer of the phenolic component recently announced that they would discontinue this product. Thus, a replacement with a similar composition was identified. This new component showed to have a faster cure rate which as a result meant that the same curing temperature and time could be used as for the... (More)
- Alfa Laval has been using its unique adhesive mixture for over 50 years for bonding of rubber gaskets to the corrugated plates used in their heat exchangers. The adhesive mix is designated GC6 and is composed out of an epoxy component and a phenolic component. GC6 has throughout the years shown exceptionally good performance in both adhesion to the rubber gasket and to the plate with minimal pre-treatments of the surfaces required. The manufacturer of the phenolic component recently announced that they would discontinue this product. Thus, a replacement with a similar composition was identified. This new component showed to have a faster cure rate which as a result meant that the same curing temperature and time could be used as for the old component. However, data on the minimum curing conditions with respect to time and temperature to obtain a well performing adhesive bond had not yet been established. Thus, the aim of this project was to investigate this. The adhesive showed sufficiently good performance when samples were cured to a residual enthalpy of <2.3J/g, both in initial bond strength and chemical resistance. This required a curing of at least 1h at 120°C and showed no decrease in bond strength after ageing for one week in a humidity chamber. For curing temperatures under 110 °C, in addition to reduced performance also a separation of the individual components. These findings suggest that the current minimum curing recommendations of 120°C for 3h are well above the findings in this report. This also opens the possibility for Alfa Laval to optimize their curing conditions to lower the energy consumption and environmental impact of each cycle. (Less)
- Popular Abstract
- In today’s industry, adhesives are widely used to bond two substrates together. The type of adhesive used depends on the application and what type of performance. For example, epoxy resins are used in the heat exchanger due to good thermal stability, chemical resistance and mechanical properties. The properties of the cured epoxy bond depend on temperature, time of cure, curing conditions, extent of cure, curing agent and what structure it has. Phenolic adhesives are used as industrial grade wood adhesives since these resins possess superior performance in heat resistance, high bond strength, water resistance and chemical stability.
Alfa Laval uses an adhesive that consist of two components, one is an epoxy resin and the other one is... (More) - In today’s industry, adhesives are widely used to bond two substrates together. The type of adhesive used depends on the application and what type of performance. For example, epoxy resins are used in the heat exchanger due to good thermal stability, chemical resistance and mechanical properties. The properties of the cured epoxy bond depend on temperature, time of cure, curing conditions, extent of cure, curing agent and what structure it has. Phenolic adhesives are used as industrial grade wood adhesives since these resins possess superior performance in heat resistance, high bond strength, water resistance and chemical stability.
Alfa Laval uses an adhesive that consist of two components, one is an epoxy resin and the other one is phenolic resin. The phenolic component recently got replaced with another component with similar chemistry and as a result cures faster relative to the old component. However, the lowest curing conditions to obtain sufficient performance, were untested.
The aim in this project was to test and evaluate the minimum curing time and temperature required to obtain good adhesive bond strength and chemical resistance. As well as testing relevance of the recommended minimum curing conditions based on the old component. A viscosity analysis was conducted to begin with, since the cure kinetics of the adhesive mix where some what unknown. The temperature where the curing starts was obtained from the viscosity analysis. Then the initial bond strength was tested with a 90° peel strength analysis and samples were prepared based on the information obtained from the viscosity analysis. Aged samples were also tested using the same method, the ageing was done in a humidity chamber to test the chemical resistance of samples cured at different conditions. A DSC instrument was used to evaluate the degree of cure to get an understanding of what the maximum residual enthalpy (in J/g) is tolerated. The test showed that the current minimum curing conditions recommended where well above the minimum curing conditions observed in this study. As a result of this project, Alfa Laval, can now further tailor their curing cycles to be more efficient and as a result have less energy waste. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9024673
- author
- Omeragic, Enar LU
- supervisor
- organization
- course
- KEML10 20201
- year
- 2020
- type
- M2 - Bachelor Degree
- subject
- keywords
- Epoxy resin, Phenolic resin, Adehisve, Adhesion, Physical chemistry, Fysikalisk kemi
- language
- English
- id
- 9024673
- date added to LUP
- 2020-09-16 16:18:14
- date last changed
- 2020-09-16 16:18:14
@misc{9024673,
abstract = {{Alfa Laval has been using its unique adhesive mixture for over 50 years for bonding of rubber gaskets to the corrugated plates used in their heat exchangers. The adhesive mix is designated GC6 and is composed out of an epoxy component and a phenolic component. GC6 has throughout the years shown exceptionally good performance in both adhesion to the rubber gasket and to the plate with minimal pre-treatments of the surfaces required. The manufacturer of the phenolic component recently announced that they would discontinue this product. Thus, a replacement with a similar composition was identified. This new component showed to have a faster cure rate which as a result meant that the same curing temperature and time could be used as for the old component. However, data on the minimum curing conditions with respect to time and temperature to obtain a well performing adhesive bond had not yet been established. Thus, the aim of this project was to investigate this. The adhesive showed sufficiently good performance when samples were cured to a residual enthalpy of <2.3J/g, both in initial bond strength and chemical resistance. This required a curing of at least 1h at 120°C and showed no decrease in bond strength after ageing for one week in a humidity chamber. For curing temperatures under 110 °C, in addition to reduced performance also a separation of the individual components. These findings suggest that the current minimum curing recommendations of 120°C for 3h are well above the findings in this report. This also opens the possibility for Alfa Laval to optimize their curing conditions to lower the energy consumption and environmental impact of each cycle.}},
author = {{Omeragic, Enar}},
language = {{eng}},
note = {{Student Paper}},
title = {{Determining minimum curing time and temperature for a phenolic formaldehyde/epoxy adhesive}},
year = {{2020}},
}