FAQs: Chemlok Rubber-to-Substrate Adhesives
A. The key is to apply Chemlok adhesives in a uniform, consistent manner that deposits a continuous dry film free of runs, sags or drips. To determine optimal dry film thickness, bond testing should be performed to decide how much adhesive should be applied for each individual application. Keep in mind that dry film thickness does affect bond quality. Typically, primers require 0.2 to 0.4 mils, while covercoats require 0.3 to 0.5 mils, and one-coat adhesives 0.7 to 1.0 mils.
A. Angular grit blast media rips and tears at the substrate surface, leaving sharp ridges and valleys. This creates the maximum area for bonding and provides an ideal wetting surface for Chemlok adhesives. Rounded shot blast, on the other hand, peens and hardens the metal and leaves “moon craters.” As a result, there is less surface area for bonding. Because surface area is directly related to adhesion quality, angular grit blasting is preferred.
A. Yes, there are Chemlok aqueous products that can replace each of the solvent-based systems. However, performance testing should be conducted to determine if aqueous replacements are feasible for the specific application. If you're considering switching to aqueous adhesives, consult your Chemlok representative for more information.
A. Solvent-based Chemlok adhesives can be hand-stirred with paddles, shaken on paint shakers, or rolled on container rollers. Aqueous-based Chemlok adhesives can be gently hand-stirred or rolled, but cannot be shaken, which causes severe foaming. These methods are adequate for 1/2 pints, quarts, gallons and pails. Air driven agitator assemblies are required for drums. The key is to ensure that all solids are dispersed in the solvent system before dispensing the material. Agitation times vary based on the type of agitator available, the size of the container, product chemistry and amount of solids.
A. Layover time before molding varies with each application; however, coated part layovers of several shifts, or days, to several weeks can be typical. Use caution when long layovers are encountered to avoid contaminants such as dust, dirt, oil, grease, mold release and moisture. When these contaminates come in contact with the coated parts, bond performance can be reduced. If long layovers are required, cover the coated parts with Kraft paper or plastic sheeting to reduce exposure to contamination.
A. The dry time varies for each Chemlok adhesive and is dependent on the type and amount of solvent carrier and its evaporative rate. Other influences are the dry film thickness, method of adhesive application, as well as plant conditions such as air flow, humidity and temperature. Typically, most Chemlok adhesives will dry in one hour at ambient temperature.
A. There are a wide variety of testing types available. The goal is to evaluate the strength of the bond at the rubber substrate interface by some type of destructive testing. Simple destructive tests, such as hand peeling or stripping, are common for visual performance results. Various test machines, such as tensile testers, are more scientific and will quantify the performance, measuring the amount of force required to break the bond. In all cases, destructive testing, both hand peel or machine testing, helps to determine the quality of the bond.
A. Prebake resistance is based on several factors: the mass and heat transfer of the part, the Chemlok adhesive system utilized, the mold temperatures, and the bondability of the specific rubber compound. Prebake time or resistance can be established through testing under the specific conditions in the molding application. Chemlok adhesives are designed to tolerate extended prebakes during high temperature transfer and injection molding.
- Keep application and storage areas ventilated and free of ignition sources.
- Wear protective clothing as needed.
- Keep work and storage areas clean.
- Clean application equipment regularly.
- Dispose of waste according to federal, state and local regulations.
- Read labels, MSDS and product bulletins before using.
A. All Chemlok solvent-based adhesives can be dried at room temperature, from 30 to 60 minutes at 24°C (75°F). If faster drying is necessary, use a circulatory air dryer at 65°C (150°F) to 93°C (200°F). Humidity plays an important role in the drying process. Extended dry times are required where humidity levels are high.
- Substrate preparation
- Primer, adhesive application
- Elastomer preparation
- Molding, curing and finishing
A. Chemlok aqueous products are a mixture of high emulsions, pigments and curatives in a water-based medium. Chemlok solvent-based adhesives consist of pigments and curatives with dissolved polymers in a solvent solution.
A. Chemlok is manufactured in one- and two-coat systems and is sure to be the solution to your bonding applications. LORD Chemlok adhesives wet and spread on prepared surfaces. Chemlok adhesives also tolerate variations in compound formulations and vulcanization processes. In addition to all this, Chemlok has account managers, field support professionals, and a technical service department that are second to none and always available to help with all of your application and bonding needs.