Topline manufacture 2 products that we recommend for painting of Grape Bins, Grape Receive equipment and basic plant. These products are 304 Chloraline (a chlorinated rubber based finish) and 116 Nylocote (a 2 pack epoxy finish).
For certain more specialised applications other products may be recommended.
This year we have received many queries from customers regarding painting of this type of equipment and this document attempts to answer some of those questions.
Primers: as a general rule ALL anticorrosive primers contain corrosion inhibitors that rule out their use in a food contact situation. This includes Toplines 127, 131, 272, 291, 858 and Forminex Epoxy Undercoat and others.
This would also apply to other paint company’s equivalents to this type of product. There is an older school of thought that the primer does not need to be food contact safe if it is over coated with a food contact safe coating and we are aware of a number of customers who have or still rely on this.
Our advice is that due to the risk of chipping the non food contact primer can be exposed to the food product and thus risk contamination/tainting. For this reason we do not recommend the use of non-food contact primers under food contact coatings.
Since the painting of aluminium is becoming more popular we are investigating a suitable food contact compliant primer – which at this stage is looking to be a non-corrosion inhibiting epoxy primer specifically formulated for aluminium.
Food Contact Approval To the best of our knowledge there is no ‘Certificate’ or ‘Certification’ that can be provided for this. The relevant Australian Standard refers us to US and EC practices. In particular we determine the food contact safety of a paint product by reference to the US FDA regulations known as 21 CFR which lists compounds and materials safe for contact with food stuffs in the form of coatings and adhesives.
We purchase raw materials from suppliers who manufacture those raws to comply with 21 CFR and use those in our Food Contact Coatings. If your concern is regarding specific contaminants or trace materials then separate testing for those chemicals is possible but is expensive and will be carried out on a commercial basis.
Both 116 Nylocote and 304 Chloraline meet the requirements of 21 CFR.
Chlorinated Rubber Coatings: This vintage we have had a number of customers concerned about the use of Chlorinated Rubber type coatings. We have heard statements ranging from “we’ve been asked not to use them” to “they have been banned”.
To the best of our knowledge the only publically available information is from the AWRI (Australian Wine Research Institute) and they in their e-News 2011 published the following statement:-
Most vintage taints are due to aromatic hydrocarbons that originate from particular paints, or paint thinners, used on grape bins and other transport vessels. These taints can be avoided by using food grade, two pack epoxy paints and by avoiding the use of chlorinated rubber-based paints. It is imperative that the paint be properly cured and should ideally be left seven to 12 days before the painted object is used, depending on the product specifications.
Topline Paint is currently discussing this statement with the AWRI as whilst we understand the risk of solvent taint from paints we see it as an application issue rather than a product issue. We believe that Chlorinated Rubber Paints are probably more susceptible to a solvent retention issue than 2 pack epoxy however any paint can have this issue if not correctly applied and handled.
Note: the AWRI’s drying recommendation of 7-12 days which generally exceeds the paint industry’s requirements.Essentially if either kind of coating is not allowed to dry and fully cure before use then there is a risk of solvent taint. Excessive thickness of Chlorinated Rubber Coatings can cause more problems as the coating will dry on top, trapping solvent in the film – solvent that may not have completely evaporated even in 12 days.
On the other hand whilst epoxies are less likely to have a thick film retention issue. However premature use can still lead to solvent taint and failure to properly cure or properly mix the correct amounts of part A and Part B can lead to amine or amide contamination of the food product.
Topline is aware that it is a standard practice in industry to use bins the day after painting due to time and cost constraints. We cannot under any circumstance support this practice and would like to make it clear that sufficient time MUST be allowed for drying/curing. Our standard recommendation is 7 days at 25oC however we fully support the AWRI’s recommendation of 7 to 12 days.
Historically speaking two decades ago there were some concerns regarding Chlorinated Rubber because of a by product of its manufacture present in the finished raw material. Carbon Tetrachloride was present in Chlorinated Rubber (the raw material not the paint) at specified quantities of up to 5%. Manufacturing procedures were revised and now the maximum amount specified in current production is 0.05% and is practically much lower. This does not appear to be a current concern however if supplying wine where Carbon Tetrachloride content is prohibited then the winery needs to be aware of this and perhaps avoid this class of coating.
2 Pack Epoxy – Is currently the preferred option of many wineries. This is a tougher coating than chlorinated rubber but far more difficult to re-coat during maintenance (unlike Chlorinated Rubber old coats of epoxy must be sanded). Epoxies also chalk on exterior exposure and bins painted the previous vintage and not stored undercover could transfer paint chalk to the grapes/juice.
There are many types of epoxy coatings on the market varying in solids/high solids/solvent free and amine or amide cured. You need to check that the epoxy you are using is Food Contact Approved as many epoxies on the market are not – there are literally thousands of amine or amide curing agents that can be used to make the pack B but only a small number of those meet the requirements of 21 CFR.
It’s also worth noting that there is some concern these days about Bisphenol A in food contact coatings such as can linings and this is also a component in many food contact epoxy coatings. There are currently no Australian or US controls on the use of Bisphenol A that we are aware of.
From Topline Paints perspective the issue of taint of wines is far more one of correct and sound application of the paint – provided you are using a product that complies with Food Contact provisions such as 21 CFR. Excessive thickness, improper or inaccurate mixing or insufficient curing/drying of paint is asking for trouble.
Remember just because paint feels dry doesn’t mean it’s fully cured or that all solvents have left the paint film. As Topline Paint can supply both types of coating we have no vested interest in supplying one or the other. However, we would make the point that Chlorinated Rubbers are cheaper and easier to use over the more difficult to use Epoxies.
If changing from Chlorinated Rubber to Epoxy then the Chlorinated Rubber must be completely stripped prior to painting with epoxy.
This document will be updated as we further investigate this matter and have discussions with the AWRI.