Micronax FAQs

Micronax Frequently Asked Questions

What kind of coating machinery is most often used with Micronax?
Gravure and Mayer rod coaters are most often used with forced air drying ovens.  

Do you have any recommendations for setting the temperature of our coater’s forced air drying ovens?
Oven temperature should be lower than 300°F (150°C). The web exit temperature should be 140-155°F (60-68°C).

Can Micronax be coated using a slot-die coating head?
Yes, Micronax 250-00 is a good product to use for sticky pad production using slot die coaters.

What coating speeds can we achieve with Micronax?
Coater speeds of 200 to 700 feet/minute (60 – 200 meters/minute) are possible for paper applications.

Can Micronax be transfer coated?
Micronax 243-02 can be transfer coated to unprimed paper.   Keep in mind that Micronax 243-02 has a relatively high acrylic PSA bonder content that results in fairly high adhesion values when compared to other, direct coated Micronax PSAs.

Why is it so important to mix Micronax prior to using it?
Our Micronax dispersion contains relatively large microsphere particles that have a density significantly lower than water. This means that there is a natural tendency for the microspheres to separate and ‘float’ to the surface. Mixing prior to use is essential to your achieving consistent adhesive performance for all product manufactured during the converting process. A mixer and vessel size should be chosen that allow for you to control the agitator speed during mixing so that a vortex is generated without foaming and splashing.

Should we filter Micronax before using it?
We feel that in-line filtering is not absolutely necessary to achieve satisfactory product performance, but will help to reduce coating defects. Using a 250 or 400 micron filter will capture any skins or coagulum that develop during the coating process.  We do not recommend using a filter size smaller than 200 microns because large particle size microspheres that are normally present in Micronax will be unnecessarily captured by the filter and become a nuisance requiring many filter cleanings. One thing to keep in mind is that Micronax dispersion is sensitive to shear and the pressure build-up that may occur in a fouled filter canister is capable of destabilizing the dispersion and may lead to the formation of coagulum. Do not allow filter canister pressure to exceed 30 lb/in2 (2 kg/cm2).

Should I be concerned about the amount of foaming that occurs during coating?
Yes, Micronax tends to be foamy unless defoamers are added just prior to use. Using foamy adhesive will reduce coat weight, especially on gravure coaters because it occupies the volume in the gravure cells.  We recommend performing a percent solids test every hour as a QC measure to ensure consistent dry coating weights are achieved.

While any oil-based defoamer should work well, we recommend Foamaster 111, Deefo 215, Surfynol DF 75 based on our own experience. You should add the defoamers while performing the essential mixing of Micronax just prior to coating. Please add 0.05-0.1% defoamer while mixing.

It is also possible to use a diluted defoamer solution (50:50 with water) dispensed into the coating pan or re-circulation drum using a hand-spray bottle. This can be helpful for decreasing foam at times when the web is not being coated and adhesive is recirculating without being consumed.

We see dry coating weight increasing with time during the coater run.  Why is this occurring and how do we prevent it?
Unless you compensate for it, the percent solids of Micronax will increase over time during the coating process. The increase is caused in part by evaporation from the pan and recirculating of the drum but more so by the paper web’s affinity for water. As adhesive material is being applied and doctored, water penetrates, rapidly leaving the doctored adhesive that returns to the pan and recirculated very slightly higher in solids content. Over a period of one hour, it is common for percent solids to increase from 32 to 36% for Micronax. To compensate, it is recommended that you add water to the recirculation container periodically.

Is it possible to design a process to adjust for the percent solids loss on a continuous basis?
Yes, however, you must first establish the solids profile for your process in order to know how much water you need to add.  For example, if you run Micronax for 60 minutes on your coater and test the percent solids content before and after, you can use the change in percent multiplied times the total quantity of adhesive on your coater and in your recirculating system to calculate the quantity of water that should be added back to your adhesive per hour. It is then possible to set-up a dropping funnel or other vessel with a sensitive adjusting valve to drip that quantity of water into your adhesive system at this same rate. It is important to remember that the pH of the water make-up solution should be adjusted to 8 – 9.5 using 21% ammonia.

Will the best choice of Micronax PSA used for sticky note type products be different for different kinds of paper?
Yes, Micronax 250-00 is much better if you apply the adhesive to porous paper. Micronax 240-00 is mainly for coated or super calendared paper.

Can Micronax PSAs be used on film substrates?
Micronax can be used on any film (PE, PP, PVC, mylar) that can be transported through a drying oven with good results. Keep in mind that using Micronax on film products is a relatively new field that often requires specially designed coating machinery.

Should we use a primer coat if we are making paper ‘sticky note’ pads?
Some manufacturers like 3M use primers where the paper is coated with a thin layer of primer to improve the anchorage of the microsphere adhesive to that paper. Other manufacturers are using microspheres that are blended with binder (traditional acrylic PSA) to improve anchorage on non-primed paper. Low binder content Micronax adhesives such as Micronax 250-00 should anchor fairly well on non-primed paper as long as the coat weight is kept in the 0.2 - 0.3 mil (0.005mm -  0.008mm). Micronax 240-00 has higher binder content and should have no problem anchoring to unprimed paper.

What coating weights are recommended for ‘sticky note’ applications?
The recommended dry coating weight is normally 6 lb/ream (3000 square feet) or ~9.8 g/m2. One pound of dry adhesive is sufficient to coat 46 m2. The solids are 32%. Therefore, you can expect 14.8 m2 of coated surface per wet pound of adhesive. So one pound of wet Micronax product can cover about 14.8 m2 (32.6 m2 per wet kg).

How soon after converting will my release values stabilize?
About two weeks under roll tension is needed for the release values to stabilize. Therefore, a minimum of two weeks should pass before you use the coated material. The reason is that the release values will be very low initially, increasing 3-5 times after two weeks before stabilizing. When you do transfer coating, the release value will naturally be at its maximum level immediately following conversion.

Are Micronax PSAs stable if frozen during transport?
In a word – NO!  Avoid freezing at all costs.

How concerned should we be regarding the storage life of Micronax?
Like many USA manufacturers of perishable products, Franklin takes a conservative view on storage life recommendations for its products.  We have given our Micronax PSAs three to six month storage recommendations because that is the period of time we guarantee they will retain their original manufacturing specifications. In no way does this mean that Micronax will not be useable after three months, it simply means that the viscosity or pH may not remain within the narrow range we use for quality assurance purposes. By their nature, the large microspheres tend to separate and rise to the surface after some time without mixing. This is why we insist that Micronax be stirred immediately before use.

We want to determine the customs duty and taxes for importing your product, what is the HS tariff code for Micronax?
The H. S. Code for the Micronax products is: 3906.90.6000

How can we get a copy of the Material Safety information for Micronax?
Visit us online at: http://www.franklininternational.com/ProductMSDSCO.php

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