Compare SIS diblock content, styrene content and test conditions before choosing an adhesive grade. Use a supplier checklist and discuss samples with Jusage.
Compare diblock content together with styrene content, polymer architecture and test conditions. Then evaluate finished adhesives with the same tackifier, oil level, coat weight and substrate. The percentage helps define a trial; it does not establish a universal best grade.
What SIS diblock content tells a buyer
SIS means styrene-isoprene-styrene. SI diblock means styrene-isoprene. Diblock content describes the proportion of the two-block component in the reported polymer fraction. Styrene content describes a different attribute: the share of styrene in the polymer. These percentages answer different questions and should occupy separate lines in a grade comparison.
The Kraton Polymers Product Guide illustrates this distinction. Its SIS tables list styrene/rubber ratio, diblock content, polymer structure, melt flow rate and solution viscosity separately. The footnote places diblock content on the styrenic block copolymer fraction. Ask each supplier to confirm the basis in its own technical file before comparing figures.
What the published label adhesive study found
In a study published on 15 September 2025, Fariba Mohammadi and Ebrahim Hashemi compared low- and high-diblock SIS in hot-melt label adhesives. Their published abstract in International Polymer Processing reports lower storage modulus and improved surface wetting, tack, peel and die cutting in the systems studied.
The study supports including diblock content in a grade discussion. The abstract does not establish a universal optimum percentage, provide a complete trial procedure or demonstrate results for Jusage grades. A buyer still needs evidence from the intended formulation and converting process.
For an existing adhesive, write down the problem first. Is initial contact poor, is cutting difficult, or does the bond move under load? Use that observation to set the trial objective. A single improvement should not replace the other acceptance checks for the finished product.
Build a comparable SIS supplier file
The table below is a purchasing checklist, not a grade specification. Request the current technical data sheet (TDS), the meaning of each reported value and the test conditions. Keep typical product-guide figures separate from contractual limits and batch documentation.
| Field to request | What to record | Comparison question |
|---|---|---|
| Diblock content | Percentage, reporting basis and supplier method | Does the figure refer to the polymer fraction or the complete formulation? |
| Styrene content and structure | Styrene/rubber ratio and linear or radial designation | Are several polymer attributes changing in the proposed substitution? |
| Melt flow rate | Value, units, temperature and load | Were both grades measured under the same conditions? |
| Viscosity | Melt or solution, temperature, solvent and concentration when applicable | Is the comparison between neat polymers, solutions or finished adhesives? |
| Document status | Revision, typical values, agreed limits and available batch evidence | Which values will govern purchase acceptance? |
For example, the SIS tables in the Kraton guide, pages 8 and 9, state melt flow rate at 200 °C under a 5 kg load. Their Brookfield viscosity uses 25 wt% neat polymer in toluene at 25 °C. Those are different measurements. The guide also says its tabulated data are representative rather than guaranteed specifications. These examples explain how to read a file; they are not Jusage specifications or recommended coating conditions.
Keep the first formulation comparison controlled
A finished adhesive contains more than its base polymer. The Kraton adhesive formulation brochure describes the use of resins, plasticizers, fillers and antioxidants. Changing these ingredients at the same time as the SIS grade makes a comparison harder to interpret.
Use this suggested trial sequence to document the comparison. It is an editorial recommendation, not a published test standard, and it does not promise a solution to a production problem.
- Record the reference formulation by mass, including the exact tackifier, oil and stabilizer grades. State whether the first comparison holds polymer loading constant.
- Use the same substrate and backing, coat weight, conditioning and test methods. For labels, record the liner and converting conditions as well.
- Measure the finished adhesive at the intended processing temperatures. Record mixing order and hot holding time, rather than relying on the polymer data sheet alone.
- Agree acceptance criteria for tack, peel and holding performance before testing. Add cutting or stripping observations when those operations are part of the application.
- Retain the reference and candidate records, including failures. If a candidate needs a different formulation, assess that optimized version as a separate trial.
Start the Jusage discussion with SIS grade data
The Jusage SIS series is the starting point for an SIS adhesive grade discussion. Use the Download Center to identify technical files, and ask which diblock, styrene and flow data are available for the grades under consideration. Request grade-specific confirmation before using a diblock percentage in a Jusage purchase specification.
If a project also considers the Jusage SBS series, treat that as a separate polymer-family evaluation. SBS means styrene-butadiene-styrene; the SIS study does not demonstrate performance for SBS. Share formulation and process requirements through the customized-service page before asking about a substitute.
Frequently asked questions
Is SIS diblock content the same as styrene content?
No. Diblock content describes the SI component on the stated polymer basis. Styrene content describes the share of styrene. A supplier comparison should show both, together with polymer structure and test conditions. Ask for the reporting basis when a data sheet leaves it unclear.
Is higher diblock content always better?
No universal optimum follows from the cited abstract. It reports benefits in the label adhesive systems studied. A buyer should compare candidates against the same application requirements, including holding performance and converting behavior. Select a grade from the finished-adhesive results and agreed limits, not the largest percentage.
What should a buyer request before ordering samples?
Request the current TDS, available composition data and their reporting basis, flow or viscosity test conditions, and clarification of typical versus specified values. Send the reference formulation, substrate, coat weight, process temperatures and target performance. Ask which sample grades are available for that defined comparison.
Discuss a grade and sample plan
Compare SIS diblock content in a documented trial with agreed acceptance criteria. Send Jusage your application requirements to discuss suitable SIS candidates, available technical documents and sample availability. Keep the selected grade, formulation and acceptance criteria together in the trial record.