I was invited by DST Technology to visit one of their PVA Sponge Roller factories located in Taiwan. This is a relatively old building with at least 40 years history. However their facility, knowledge and control system is one of the best PVA sponge roller factory which I ever seen before.
PVA Sponge Products
There are many applications for PVA sponge roller. We have seen the PVA sponge roller being used in industry cleaning, household cleaning, medical application and personal use. In this factory, the PVA Sponge Roller products mainly used in wafer cleaning, HDD substrate cleaning and TFT, LCD cleaning. 2 products really impressed me most; the first one is nodular sponge roller and follows with the 3.2m long PVA sponge roller used in TFT panel cleaning.
PVA Sponge Roller Process
Many people have been interested to know the PVA sponge roller process especially the know-how on manufacture the consistent quality sponge roller. I did discuss with their researcher about some formulation control unfortunately I have to keep the conversation within our private group. However, the key criteria for making a quality PVA sponge roller are the foaming process. In order to achieve high quality PVA sponge roller products, the manufacturer has to ensure the PVA sponge is having appropriate foaming.
There are many factors affecting the foaming result, an experience manufacturer will judge the foaming result by their sense, such as hand feel, visual. In modern technology, we could measure some process parameters such as temperature, viscosity, hardness, in order to determine the foaming quality. Among all those parameters, hardness is the most important parameters.
The PVA foam will be pour into a dedicate mold for getting the PVA sponge mold. The entire mold shall keep under a temperature control room for 12 hours in order to ensure PVA reaction process is completed.
After 12 hours reaction time, the sponge shall be released from the mold. The sponge release process is carrying out at a control room with minimum exposure to the environment. The sponge shall be fully inspected and cut into the dimension length as needed.
The product shall send to Class 100 clean room for sponge cleaning. After cleaning, the sponge will directly pack the inner layer in the Class100 clean room. The second layer packing bag shall pack in outside packing area. To ensure better packing condition, there are using Nylon bag as the outlet layer bag, they also insert Nitrogen and desiccant pack within the layer.
PVA Reaction and Foaming
As I mention earlier, the foaming is the most critical part in PVA sponge roller process. What is about the foaming process? The foaming process is the reaction process within PVA material and aldehyde. This is not top secret recipe within the industry, the challenge in this reaction process is about the cleaning process on removing the Formaldehyde within the products.
DI Water Cleaning and Waste Water Disposal
Through our discussion, I learned that they are using 18Mohm DI water in cleaning to ensure product quality. More important, the waste water will be treated in a water treatment centre and store before disposal. The treated waste water will be passed to qualify water treatment plant for disposal. This is the most impressive part and commitment shown.
I have visited other PVA sponge manufacturers, most of the manufacturer directly discharge the waste water into drain without proper water treatment process. This is really worrying me as the waste water content high level of Formaldehyde which will bring direct impact to the environment. You can learn the treating waste water containing Formaldehyde here.
For PVA sponge roller with insufficient cleaning will expose to high level content formaldehyde residue in the products. The high level formaldehyde will direct impact to product quality which always been neglect by many users. I am very proud as DST Technology has brought up this topic sometime ago about the impact of Formaldehyde on PVA Sponge Roller.
This is a very simple and brief visit. It covers brief presentation about company profile, technical discussion and line tour. The entire process completed within 2 hours. I am very impress with their PVA sponge roller knowledge, commitment to achieving quality product as well as environment commitment.