Suggested handling approach for composite industry Chemlease release agent
Chemlease release agents’ ability to release is dependent on an evenly formed application, producing a thin polymer film. The layer is cured by means of air humidity and warmth. It is essential that the release agent film is intact and fully cured. The thinner the layer is spread, the quicker and better it cures. This process is repeated to ensure all areas form a cohesive film.
Manufacturer recommended treatment for reinforced plastic mould:
Mold Cleaner EZ – used to clean the mould.
Chemlease MPP712 EZ – (primer) forms a hard solvent resistant surface as a base layer for a release agent.
Chemlease C15 Sealer – mould sealant.
Choosing a Chemlease release agent depends on the production technology, the product being manufactured, and possibly other requirements; such as surface properties.
It is recommended that all treatments be handled with 100% cleaned cotton cloth(Chemtrend cleaning cloth).
Chemlease 75 or Chemlease 41-90 release agents are recommended for products manufactured from polyesters. Chemlease 41-90 is most suitable for products made from vinylesters.
Chemlease 75 or Chemlease 41-90 release agents are both suitable for products manufactured of polyester, however, Chemlease 41-90 is better suited for vinylester products. Chemlease 255 or Chemlease 75 are recommended for epoxy manufacturing. For spray applications, Chemlease One FS EZ is suitable.
Manufacturer recommended instructions pertaining to reinforcement mould handling for polyester, vinylester, and epoxy products (general instructions):
- Clean mould with Mold Cleaner EZ solvent twice
- Prime the mould with Chemlease MPP 712 1-2 times so the surface is glossy
- Add 1-2 treatments of Chemlease C15 sealer (spread and dry). Waiting time between treatments is a minimum of 15 mins and after the second treatment extends to 1 hr minimum.
- Add two treatments of Chemlease 41-90 release agent (spread and dry). Waiting time between treatments is a minimum of 15 mins and after the second treatment extends to 1 hr minimum before product manufacturing begins.
Always use 100% cotton cleaning clothes for applying treatments.
By instructions from the manufacturer, spray treatment can also be used.
Mould and cleaning
Reinforced, plastic moulds need to be fully cured before applying the release agent. The mould laminate, if under-cured, could release styrene, contaminants, deform the release agent layer, and react with the manufactured product’s resin; thereby adhering to one another and preventing release.
Mould surface cleaning prior to applying the release agent is essential. Poorly cleaned surfaces may prevent the release agent forming a properly uniform layer. For cleaning we recommend Chemlease MoldCleaner EZ solvent.
Cleaning is performed with a solvent soaked cotton cloth. Repeat cleaning as many times until all fats and contaminants are removed. Old moulds may need to be mechanically polished before the release agent will suffice as a functional release surface.
Handling release agents in the winter
Problems can arise when handling release agents when the temperature is below zero. Indoor temperatures are typically 17 -20°C and the humidity is usually separately measured and controlled. Treatment should be performed at relative humidity levels of 30% which is subsequently the lower limit for release agent applications.
The manufacturer’s recommended limit of 30% should be obeyed, however in Finland this is not always possible. One solution is to add humidity to the ambient air by means of a spray bottle, but great care should be taken so as never to expose the prepared surface to water droplets. Another option, in assissting curing of the release agent, is to add heat to the mould.
Standard recommendations for handling release agents are to operate slowly and carefully. If the treatments are done too quickly, they will be applied to partially-cured layers, where problems will occur: the distribution integrity of subsequent layers will be flawed and upper layers will interrupt the polymerization process of the lower layers.
Sufficiently sealing moulds
Chemlease MPP 712 EZ primer should be utilized before the sealer and release agent are added, especially for gelcoated polyester, epoxy, and steel moulds. The sealant (Chemlease C15 Sealer) forms a dense film on the mould’s surface, thereby sealing any exposed pores. It’s sole purpose is to inhibit gases and solvents from entering the mould during production so that the release properties are not adversely affected. Sealing is especially important if the mould is porous. The sealer serves as the foundation for the release agent, and needs to be replaced only when the mould recieves a complete servicing and cleaning after every 10 or so manufactured products.
Release agent replacement criteria
In general, the replacing of the release agent layer and it’s release properties are monitored and judged by the ease of release and the dullness of the mould surface. If damage of any sort has occurred, the sealant layer must be replaced as well. Normally the same release agent layer can be used about 10 times before it must be replaced.
Testing release layer functionality
A successful release agent layer is tested by using masking tape, where a piece of tape pulled upward at a 90 degree angle from the mould surface should be noticably much easier to remove from a treated surface than an untreated surface. However, this test should never be performed on an incompletely cured surface. What you should observe is, if the release agent layer isn’t cured properly, the tape will pull off the layer and subsequently will not stick to anything else. If this occurs, either the cleaning stage was not done properly and/or the release layer did not fully cure.
Example of handling release agents (in winter)
1-2 treatments of Chemlease C15 sealer and 3 treatments of Chemlease 41-90 release agent should be added to the mould’s surface. 30 minutes should be waited for curing between layers. This waiting time is significantly longer than recommended by the manufacturer because the lack of humidity lengthens the curing time. Upper layers can not be added until lower layers have fully cured.
Curing integrity can be tested by dripping a droplet of release agent onto the surface and immediately wiping it away. IF GREY SPOT APPEARS AFTER THE DROPLET IS WIPED AWAY, WAIT LONGER UNTIL THIS DOES NOT HAPPEN AND THE SURFACE IS FULLY CURED BEFORE MANUFACTURING CONTINUES.