Plastic resign glue, commonly known as urea resin glue, is mainly used in the wood work industry as a construction adhesive. This glue is available in both liquid and powdered form. Liquid resins generally come with a powdered catalyst, while powdered plastic resin glue is usually pre-catalyzed and pre-formulated and can easily be mixed with water. The term pre-catalyzed implies that urea and formaldehyde, the components of the glue, are already mixed; generally, this glue does not require hardeners while mixing.
The ideal amount of water used for mixing the plastic resistant glue should be approximately 60% to 65% of the weight of the powder. The powder should be added slowly to water and mixed gently until it reaches a heavy cream-like consistency. The powder that settles on the sides of the container should also be scraped into the mixture until the final result is smooth and lump-free.
Powdered plastic resin glue has a shelf life of approximately one year. This shelf life decreases to less than six months if it is stored under high temperature, around 90°F (32°C), and high humidity. If the powdered plastic resin glue mixes with water to yield a grainy consistency, it is not fit for use. Moreover, if the powder does not easily dissolve in water, this is a pretty clear sign that the product has passed its shelf life.
The time it takes for the glue to harden, or the "cure time," varies from eight to ten hours, depending on the surrounding temperature. Therefore, this glue is suitable for use in wood work applications, wherein the unhurried assembly of parts is common. The higher the outside temperature, the faster is the curing process.
Plastic resin glue can either be hot or cold pressed. It can also be radio frequency-cured (RF-cured). One of the main advantages of plastic resin glue is its longer "open time" than many other adhesives, which is more than half an hour. Open time refers to the time duration between when the glue is applied to when the material is placed in the press.
The "pot life," the period of time between mixing and use, ranges from four to five hours if the surrounding temperature is around 70°F (21°C). The glue can be refrigerated to extend the pot life, but not below 55°F (12.7°C), as it may adversely affect the ease of application. Freezing the glue is not advisable.
Plastic resin glues are widely used for lamination and veneering applications. It is necessary to use a thin spread of the glue while working with raw veneers so that it does not bleed through. Plastic resin glue is an ideal choice as a water- and heat-resistant construction adhesive and wood glue.