Product Incident Report - Rock & Rubber Yellowing Binder

Product Incident Report - Rock & Rubber Yellowing Binder

Product Incident Report 

Binder Issues: Rock and Rubber Yellowing Binder

(September 2021) 

Background Information

A pail of Rock & Rubber Non-Yellowing (RRNY) binder behaved abnormally resulting in faster cure times compared to normal RRNY binders. The main issues were observed in the summer of 2021 in Kamloops BC and in Regina SK. The first sign of a potential problem was the large color variations between the batches. The next issue was faster curing times and viscosity issues.


Fig 1. The images above are multiple RRNY binder batches: batch 37 (left), batch 69 (middle) and batch 16 (right). Note the large color variations between the batches.


Fig 2. The image above is a RRNY binder (Batch 2104024), that exhibited high viscosity. Note the accumulation of binder around the stirring stick.


Fig 3. The image above is a RRNY binder that almost has completely cured within the pail. 

Observations

Multiple installers noted that multiple batches of our RRNY binders cured faster than prior batches.


Fig 4. The image above is a text message of the batch number of a pail of RRNY binder that cured faster than previous batches. 

The main observation of the installers was that the coloration of the abnormal batches was darker in color compared to previous batches. However, it was clear during in-house testing that coloration of the individual batches has no direct correlation to how abnormal the binders are preforming. Color tone was mainly used a visual identifiers of the different batches. The other characteristics of the abnormal batches was an increase of stickiness and higher viscosity compared to previous batches. In some cases the most viscous samples had semisolid pieces mixed in with the viscous-liquid portions (see Fig 2). In the most extreme case, the entire pail partially cured in a semi-solid gel-like state (see Fig 3.).


Fig 5. The image above are test samples using the abnormal batch numbered binders as part of the in-person examination of the abnormal binders in Regina, SK.


Fig 6. The image above are more test samples of the abnormal batch numbered binders made prior to in-person examination. Note the foaming of the cured samples.

In experimental testing of the samples using the abnormal batch numbered binder, there was in-person testing onsite of the abnormal binders. During this test no foaming or any other abnormal behavior was observed in the prepared samples, where everything appeared normal. However what was unusual was that one month later these abnormal pails continued to cure in the pails until they formed into firm gels or semi-hard gels. So these abnormal binders exhibited a shorter shelf-life compared to the standard products.

Conclusions 

Based on the combination of tests done and correspondence with the manufacturer of this binder, it has been concluded that the issues with abnormal batches were the result of accidental introduction of moisture during production process prior to shipping. This excess moisture content in these binders resulted in premature curing of the binders in the pails. The reason for the observed range of coloration of the pails was a direct correlation to the amount of “pre-curing” in the pails (i.e. the darker the color the more pre-curing) which is related to the amount of excess moisture content found in the individual batches. Using this abnormal binder gave poor installation results in which in two instances the entire install had to be redone at the request of the customer. We also gave the customer the option of working through the problem or returning the pails. Some cases pails were returned and others credit was offered for any potential problems.