ROOM TEMPERATURE CURING EPOXY ADHESIVES FOR DIFFICULT BONDING
PROTAVIC Metregrip 303 series is a unique class of room temperature curing epoxy adhesives specifically designed for difficult bonding operations with most engineering materials. Metregrip 303 series has excellent wetting and penetrating ability due to the presence of highly polar groups within the molecule. Metregrip 303 is a two-component system available in four different viscosities. The product designations in the series are distinguished by their different consistencies ranging from a very thin syrup to a thick paste.
Match the type of adhesive to the job and select the consistency you need from this table.
Metregrip 303 series forms strong bonds with a variety of engineering materials:
|Brass||Nylon ® 6-6|
Bonds formed using Metregrip 303 Series are tough, tenacious, resilient, and resistant to water and a variety of other chemicals. With Metregrip 303, shrinkage stresses are minimized, resulting in a stronger and more durable bond. The Metregrip 303 Series is ideal for applications where close tolerances are required.
The Metregrip 303 Series Epoxy adhesives can also be cured via heat acceleration. Using heat will generally result in an improvement in temperature and chemical resistance. These systems have outstanding resistance to most solvents, weak acids, and alkaline systems.
Metregrip 303 Series is easy to use in original assembly operations and for field repairs. The noncritical mix ratio and room temperature curing capability avoid the need for special handling and curing equipment.
• Easy 1-1 mix ratio for standard systems
• Can be flexibilized by adding Activator in greater proportions
• Excellent solvent resistance
• Excellent adhesion to most substrates
• Good balance of physical and mechanical properties
• Available in four different viscosities
• A PROTAVIC standard product, always in stock and available for fast shipment
Metregrip 303 Series is typically mixed at a ratio of 1 part Base to 1 part Activator. However, to improve impact resistance and flexibility, and to obtain as low as a Short A 80 durometer material, the system can be mixed to concentrations of 45 parts Base to 125 parts Activator. The gel time (the time at which the viscosity doubles) and exothermic temperature rise is dependent on the size of the mixed batch, the ratio of activator to base, and the mixing temperature. Cure at room temperature depends to a large extent on the exothermic temperature rise. In thin (2 mil) sections an overnight cure is required for the composition to achieve handling strength. PROTAVIC recommends an adhesive thickness of 2-5 mil to achieve ultimate bond strength.
In addition to room temperature cure capability, the Metregrip 303 Series may be cured rapidly at elevated temperatures. Review the user data section of this bulletin for more information.
TYPICAL PRODUCT PROPERTIES OF UNCURED METREGRIP 303 SERIES BASE AND ACTIVATOR
|PROPERTY||303 ACTIVATOR||303 BASE||303 MV ACTIVATOR||303 MV BASE||303 LV ACTIVATOR||303 LV BASE||303 VLV ACTIVATOR||303 VLV BASE|
|FORM||Thick Paste||Thick Paste||Thick Cream||Paste||Thick Syrup||Syrup||Very Light Syrup||Thin Syrup|
|Flash point º C||262||252||262||252||262||197||184||73|
PRODUCT USER DATA
Directions for Use:
1. Select the appropriate Metregrip 303 Adhesive
2. By weight or volume, measure equal amounts of Activator and Base
3. Mix thoroughly. Deaerate if necessary @ 27inches of Mercury.
4. Apply the adhesive in 2-5mil thickness to one surface. Make joint, fixture and place if necessary.
5. Cure according to cure schedules listed in table below.
|Time (hr:min)||Temp. ° C / ° F|
If initial cure is at room temperature ( 25º C), PROTAVIC Metregrip 303 Series should be post-cured to achieve optimal properties as follows:
1.2 weeks at 25º C or:
2.2 hours at 100º C
Post curing the Metregrip 303 Series at elevated temperatures after room temperature cure will result in superior heat and chemical resistance.
TYPICAL CURED STATE PROPERTIES
Not to be used for specification purposes
|Metregrip 303 & 303MV||Opaque, Tan|
|Metregrip 303LV||Clear, Amber|
|Metregrip 303VLV||Clear, Straw|
|Specific Gravity (25º / 25º C)||1.05|
|Operating Temp. Range||ºC -65 to +145|
|ºF -85 to +293|
|Heat Deflection Temp. Under Load (264 psi), ºC / ºF||72 / 162|
|Glass Transition Temp., ºC / ºF||+65 / +149|
|Linear Expansion Coefficient to 130º C, (length/unit length/ºC)||86 x 10-6|
|Thermal Conductivity, (BTU · in/hr · ft2 · ºF)||2.4|
|Weight Loss in Air 24 hours at 150º C, %|
|Metregrip 303 MV||0.25|
|Metregrip 303 LV||0.05|
|Moisture Absorption, %|
|Metregrip 303 MV|
|24 hour immersion||0.59|
|2 hour boil||0.80|
Technical information and recommendations made by Protavic America, Inc. concerning products and uses or applications thereof, are based on reliable laboratory tests and are believed to be accurate. No warranty, however, is expressed or implied, nor is any warranty expressed or implied as to results to be obtained from use of said materials, whether used singly or in combination with other products. No statements made are to be construed as constituting a license under any existing patent.