ASO Co., Ltd.

As a manufacturer of clean polybags, we consider resin grade to be the most critical factor.

Resin grades are generally expressed with code numbers, such as “E-XXX” or “RXX-X.”

In the clean film industry, these grade codes reflect the technical expertise and know-how of each manufacturer.
 Selecting grades with low levels of insoluble particles and impurities, and excellent film strength, is a common challenge across the industry.

Currently, the resin industry is undergoing a significant transformation.

Mergers between resin manufacturers and the consolidation of resin grades are changing the market landscape.
 Resin manufacturers are moving away from producing a wide variety of grades in small batches to enhance competitiveness.

In practice, the current resin grades have become over-customized for individual customers, resulting in an increase in semi-custom grades.
Even within the same base grade, slight differences in additives create multiple sub-grades.

Consequently, the industry is moving toward consolidating resin grades, while downstream processors add secondary additives as needed to meet specific customer requirements.

However, in fields such as pharmaceutical and semiconductor packaging, such consolidation is not straightforward.
 Even additive-free grades with similar properties from the same manufacturer cannot be evaluated based solely on the “additive-free” label.

The pharmaceutical industry is governed by regulations such as GMP, and it is essential to carefully verify that packaging films do not adversely affect the contents over extended periods.

Measurements of insoluble particles and metal impurities in additive-free grades from different resin manufacturers reveal significant variations beyond normal tolerances.

 As a result, it is necessary to conduct pharmaceutical testing and, where applicable, retest according to international standards.

The resin industry is also shifting from radical polymerization of low-density polyethylene (LDPE) to ionic polymerization producing linear low-density polyethylene (LLDPE).

 This trend is expected to continue over the next decade, and resin manufacturers are leveraging new technologies to enhance competitiveness.

However, ionic polymerization presents a major challenge: residual catalysts and metal co-catalysts may remain in the resin.

While these traces are negligible for food packaging or general packaging, they are critical in pharmaceutical and semiconductor applications.
Catalyst residues can potentially react with filled contents, cause cloudiness, or be perceived as foreign matter.
Since these residues exist as ultra-fine insoluble particles below 1 μm, strict management is required.

In the pharmaceutical field, considerations go beyond mere business interests.
The medications contained in the polybags we manufacture may one day be consumed by ourselves, which underscores the need for thorough testing.

Therefore, selecting the appropriate resin grade requires evaluating not only product performance but also:

Our company dedicates maximum effort to gathering information and selecting the most suitable resins for each application.