•  On May, 24, 2018
•  admin
•   Detergent, Surface Cleaning

User installed filter in detergent pipeline, this is because we have to ensure the solution cleanliness quality for removing particulate.  Hence the filter housing material is one of the commonly asked questions we receive from user.

Recently we received an inquiry from our user who has intention to apply filtration in the process.  They come across a filter housing build with SAN material, SAN stands for Styrene Acrylonitrile.  They wonder if SAN material filter housing could be selected for filter our detergent.

SAN is a kind of chemical plastics, basically we have to understand the effect on chemical plastic.  Before we dealt into the chemical aspect, let us clarify some basic knowledge.  Hope this will help us to understand the situation better.

Effect of Chemical on Plastic

If a chemical is affecting a plastic, means that the detergent is reacting with the housing material.  If the plastic housing material has low resistant against the detergent, one or more of the below symptoms may happen:

1. Chemical attack on the polymer chain.
2. Physical change of plastic material properties.
3. Stress cracking

We will see the filter housing get age and eventually damage after some time.

The Reaction of Chemical Attack the Plastic

The detergent chemistry is having the direct impact against the plastic filter housing, however the situation may get worsen in some working condition.   In ordinary environment, the attack to plastic could be enhance by a few factors such as：

1. Temperature
2. Pressure
3. Exposure time
4. Chemical concentration

If you are seeing the plastic filter housing is damaging faster than expected, you may have to review the working condition to evaluate if there is any change recently.

Stress Cracking

In our ordinary usage, stress cracking effect is the most common scenario we encounter.  There are several possible causes which could create stress cracking on the plastic material, this include

1. Detergent
2. Surface active chemical
3. Lubricant
4. Oil
5. Ultra pure water
6. Wetting agent
7. Brightener

As you see, there are too many factors actually is affecting the plastic filter housing.  In this case, user could confirm if the plastic filter housing is resisting the detergent chemical.

Filter Housing Selection

After having the basic understanding about the root causes and factors which affecting the life span of plastic filter housing, now this is the time for our selection.  From our experience, we are seeing user is using Stainless Steel filter housing, and this seems to be a good idea as Stainless Steel is most stable metal product.  DST as a knowledgeable detergent supplier, we always provide guideline for user to select filter housing material.
Guideline for Industry Application:

1. Mostly select PP material. PP material is almost suitable for many chemical and detergent.
2. For user who needs transparent surface, then select PVC material. However PVC is less robust as compare to PP.
3. For working solution higher than 80C, then user has to select stainless steel material.

Normally we do not select SAN material as commonly used in household environment.  This is because Styrene material is more easily to crack after in touch with chemical.

User could always refer to the the Material Resistance Chart for user who want to study more about compatability between chemistry vs. plastic material.

After understanding the above explanation, we recommend our user used filter housing with PP material instead of SAN material.  With PP material, we are very confident the filter housing should be able to stand for our detergent for next 5 years.
Talk to DST if you are facing similar concern on selecting suitable Filter Housing Material.