In the field of food processing, you will see some polyurethane components. You will find them in transporting, manufacturing and packing processes as well. Known for its strong abrasion resistance, it is perfect for various wear components contacting food packaging and the food itself.
Food safe polyurethane is generally used for chute liners, conveyor guides, rollers, bumpers, sprockets, and belt scrapers. And most importantly, they are used as seals and protective coats.
But now, let us see what else food safe polyurethane can do. Then, later on, we realize its significance in our daily routines in life.
When we talk about food-safe finishes, there can be many terms that may be used interchangeably. Oftentimes, it confuses and may end up doing the wrong thing. If we will analyze and research deeper on each term, there are certainly differences.
As with the terms shellac, varnish, lacquer, and polyurethane, the important details will be discussed to you one by one. Although they are all used as a reference to the final finish, they are not the same nor recommended in replacement of the other.
Shellac is a natural finish product which is the combination of the solvent like alcohol and the female lac bug. Once hardened and dried, it is safe to use. Aside from being a protective coat, Shellac adds warm amber when applied to a wooden surface. However, heat affects its presence so easily or other chemicals. Thus, it is not useful for kitchen tables and similar objects.
It is often used in furniture pieces that need enhancement. The manufacturers suggest using this coat in non-wood items. It can be applied using cotton rags or a natural bristle brush. You can buy this coat in home centers and sealed in cans.
This term is generically used for topcoat or finish. Due to its high solid ratio, the varnish is quite durable. For outdoor coating projects, you can use spar varnish. It is also used in raw woods for trim and exterior doors on most rustic homes.
Aside from protecting your wooden objects, the varnish is also an excellent shield against natural UV light. Moreover, spar varnish is typically applied to objects that can be close to water such as decks, beach chairs, and wooden boats. You just have to use a natural bristle brush to apply it on the surface.
This type of protective coating delivers immense gloss making it popular in most ultramodern furnishings. What’s more, it is resistant to damage and extremely durable. However, it gradually discolors and gets scratched over time.
Have you ever wondered why it is smooth? There is a technique used to achieve such texture – using a sprayer. In the first place, lacquer is thinner compared with other finishes. You should have HVLP (high-volume low-presser) spray to apply it on the wood surface. Plus, you need to do it in a spacious and well-ventilated area.
Polyurethane is a kind plastic in the liquid form when it dries. Nonetheless, this is available in oil-based and water-based options. They vary from satin types to glossy.
Due to its low toxicity and low odor, water-based type of polyurethane is more popular. It even dries fast. When it comes to shellac, these water-based types do not hold uptight to chemicals and heat. So, they work well with desks, picture frames, side tables or anything that does not get exposed too much to extremes.
Meanwhile, an example of water-based polyurethane is the water-based polycrylic which can withstand rough conditions. This can be applied over any oil-based finishes even when using those synthetic-bristle brushes. You can also rags or foam rollers.
For oil-based polyurethane coats, they are a bit more durable compared with those water-based types. This is evident especially in terms of handling the heat. With this characteristic, it is an ideal thing for kitchen tables. Oil-based polyurethane adds the rich color of your woods.
Every time you use this oil-based type, make sure you utilize a respirator and work in a well-ventilated space. Then, use a rag or a natural-bristle brush to apply. Since it takes some time to cure and dry, make sure you observe the directions of the manufacturer accordingly.
You can apply both types of polyurethane to acrylic or latex paints. However, oil-based one may create an amber hue or yellowish color, especially when applied to lighter shades. If you wish to improve its durability without affecting the color, try water-based finish instead.
Today, polyurethane is also available in spray making it pretty easy to apply, particular for larger projects. There is also wipe-on polyurethane which is a popular option among woodworkers who are creating ‘hand-rubbed’ finishes on their special projects. These two options deliver impeccable results.
In this article, we want to help you get accurate answers as much as possible. So, we have gathered some helpful questions and provided answers in an easy to understand manner.
These are the following:
There are agencies that focus on these food contact applications. Specific programs may be developed and laws may vary depending on the country or state. The Food and Drug Administration (FDA) of the United States, for example, has established its workforce to ensure that all components associated with food contacts including processing equipment and food packaging, will be safe.
Polyurethane is generally used in various food contact applications. These include conveyor system, chute liners, chutes, seals, hoppers, gaskets, tubing, and hoses. It is also used in adhesives for flexible and rigid food packaging.
Polyurethane can only be used in any food contact application if it adheres to every general provision that is applied to indirect food contact additive. It should meet all the test requirements and other specifications for safety purposes.
It is paramount to match the best food-grade materials for your foods. However, this is not just about developing the food-grade component. Instead, it is about the selection of your food-safe material. In addition to this, we should also research if a material, such as polyurethane, is compatible with various aspects of the application.
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