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Resin Diagnosis

Improvement of competitiveness is a requirement faced by all companies in the globalized and highly competitive world in which we currently live.  An organization is competitive and grows when can offer to its customers more value for their money than that offered by its competitors.
One way to do this is through Quality improvement and differentiation, making products that have highly desirable characteristics at lower costs.  Below is a brief evaluation guide to determine the areas of opportunity that represent better competitiveness of your PVC resins.
 
ARE YOU HAVING CURRENT QUALITY PROBLEMS?
 
They are the most obvious and should be given the highest priority.  Either a lack of conformity with the specifications or if a customer is not satisfied with the performance, it is necessary to act without delay so as not to further deteriorate the image of the product and the company, since it is very difficult to repair a damaged reputation.
However, it is necessary to avoid a long/costly process of "trial and error" and to make rapid and effective changes having the backing of a deep knowledge of suspension polymerization process, because if the effects are not identified in advance then resin Quality can get worse and complicate the competitive situation.
With deep experience and knowledge in VC Suspension Polymerization I can offer as a Consultant prompt and efficient troubleshooting of Quality problems, including but not limited to adjustments of Molecular Weight, Grain Size Distribution, Bulk Density, Porosity, Thermal Stability, etc., describing in any side effect that may arise as a consequence of the proposed changes.
 
 
ARE THERE RESINS IN YOUR MARKET WITH BETTER ACCEPTANCE OR PERFORMANCE IN PROCESSING?

 

Sometimes PVC plants have production that meets Quality specifications, but their markets suffer a gradual penetration of competitive products that appeal to customers for reasons that they do not know how to explain but that are noticed during processing.   This increases Costs in general (Technical Service and discounts in particular) to maintain sales and avoid greater market losses.
The reason is that PVC resins have different morphological characteristics that vary according to production conditions, which slightly affect the amount of energy (mechanical and thermal) and additives (thermal stabilizers, lubricants, processing aids, etc.) needed to perform proper processing during the manufacture of PVC products.
A PVC resin with unsuitable morphological characteristics will be at competitive disadvantage compared to high-performance resins that have optimum characteristics for the application, since the difference in energy and additive costs could reach up to 10% (in addition to the aforementioned increases in Technical Service costs and discounts).
There are several methods to observe directly or indirectly the morphology of S-PVC (SEM microscopy, density fractionation, optical microscopy coupled with liquid absorption, etc.) but Mercury Intrusion Porosimetry (MIP) is a very useful technique with several advantages:
         Sample for analysis large enough to be representative
         High repeatability and reproducibility
         Quantitative results showing average and dispersion characteristics
         Information from internal morphology can be extracted
 
You can then optimize a resin using the information of its internal morphology and improve its performance in a particular application.
1. Rigid applications (pipe and profile)
 
The following are well-known morphological characteristics highly desired in PVC resins for these applications:
         High bulk density
         High lot-to-lot consistency
         Internal structure that allows an efficient removal of residual VCM
         Internal structure that disintegrates homogeneously during processing
 
Using SEM it is possible to directly observe grains of a resin with high performance in processing (LEFT, high extrusion productivity) compared with a resin with lower performance (RIGHT).  Although differences in external appearance are observed, the quantitative information that can be extracted by image processing is limited to grain exterior.
MIP analysis allows us to "see" the interior of both resins through mercury intrusion both due to the collapse of internal structures and the penetration into voids (pores).
By extracting morphological information from both MIPs, it can be understood that the greater packing of Primary Particles in Problem resin results in higher energy consumption for processing (and therefore more protective additives) compared to Top Performance resin.
2. Flexible applications (K70)
 
The following morphological characteristics are highly desired in PVC resins for these applications:
         Fast absorption of plasticizers and liquid additives
         Lot-to-lot consistency
         Internal structure that allows an efficient removal of residual VCM
         Internal structure that allows homogeneous absorption of plasticizers
SEM images show that the external differences between grains of a good performer (LEFT) and a poor performer (RIGHT, presence of gels and imperfections) for flexible applications are not so obvious or notorious.
MIP analysis shows that there is a more noticeable internal difference due to the different response of different grains / zones to the increasing pressure that forces mercury to penetrate.
When extracting morphological information of both resins, it is observed that Problem resin has greater global porosity due to the presence of large voids.  This allows a fast absorption of plasticizer but does not ensure a homogeneous distribution of the same in all grains when the process of PVC swelling with plasticizer is completed.
On the other hand, although Problem resin has low porosity in highly packed zones, the pressure required for mercury to penetrate there is significantly higher, which means that plasticizer will also have difficulty penetrating and therefore there will be a plasticizer deficit in such volumes.
Problem resin has morphological characteristics that produce poor distribution of plasticizer, with some zones with high plasticizer concentration and other with poor plasticizer concentration, which is shown as formation of plugs in extruder meshes and the presence of gels (imperfections) in finished products
 
As a Consultant I can offer you a diagnosis of the morphological characteristics of your PVC resins as well as propose alternatives to increase their processing performance, in order to improve your competitive position.
Let me help you understand and control your SPVC resins.
View my PROFILE and visit my CONSULTING SERVICES page.

© 2022 Carlos Aguilar / PVC Expertise

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