01 SLIP AND BLOCKING EVIDENCE
Film COF vs blocking: separate sliding from layer adhesion
Coefficient of friction and blocking can appear in the same roll-opening or feeding problem, but they answer different measurement questions. ASTM D1894 covers starting and sliding friction between an identified surface pair. ASTM D3354 quantifies the degree of unwanted adhesion already existing between film layers; its public scope says it is not intended to measure susceptibility to blocking.
02 DECISION FRAME
Related surface symptoms do not make COF and blocking one metric.
ASTM D1894-24 reports static and kinetic coefficients for surfaces moving against one another and warns that film age, surface condition, additives and the delay before motion can affect the result. ASTM D3354-21 reports an existing blocking load under its parallel-plate method. ISO 11502:2018 instead assesses blocking tendency after films remain in contact for a stated time, temperature and light-pressure condition. ASTM says D3354 is similar to ISO 11502 Method B but not technically equivalent. None of these scopes supplies a conversion between COF, blocking load or blocking tendency.
- A quotation, TDS or COA that says low COF or low blocking without a complete method and specimen basis
- A roll-opening or feeding complaint where sliding resistance and adhered plies must be diagnosed separately
- A supplier comparison involving slip or antiblock language, sample ageing and different test records
- That a COF result approves blocking performance, or that a blocking result predicts static or kinetic COF
- That lower COF always means lower blocking; formulation, surfaces, age and contact history still belong to each decision
- That ASTM D3354 measures susceptibility, or that ASTM and ISO blocking methods are equivalent
- That matching units or a shared roll symptom justify an equation, normalization or cross-method acceptance limit
03 COMPARISON MAP
Keep sliding friction, existing blocking and blocking tendency in separate rows.
Use the map to identify the event, selected method, specimen history and purchasing decision before requesting or comparing a result.
Swipe or scroll horizontally to review every evidence column.
| Decision field | ASTM D1894 COF | ASTM D3354 blocking load | RFQ / report control |
|---|---|---|---|
| Measurement question | How an identified pair of surfaces resists starting and continued sliding | How much unwanted film-to-film adhesion already exists in the tested specimen | State whether the decision concerns slip, drag, layer separation or more than one event |
| Reported output | Static coefficient, kinetic coefficient or both under the selected test basis | Blocking load under the selected current method | Retain the original output name, unit, statistic and report wording; do not convert one metric into the other |
| Surface configuration | Film against itself or another identified substance, with both working surfaces named | The identified film layers and sides that were in contact before separation | Draw Side A / Side B, treatment, print, coating and seal orientation on one map |
| Age and surface state | Film age, storage, conditioning, additive migration and surface condition can affect friction | Processing, storage, temperature, pressure and contact history can affect existing adhesion | Keep production, packing, opening, conditioning and test dates beside each specimen |
| Interaction inside D1894 | ASTM notes that the static result can depend on loading rate and blocking between the sled and plane before motion starts | That interaction does not turn the D1894 output into a D3354 blocking-load result | Record the licensed method setup and delay fields used by the responsible laboratory without relabelling the output |
| Susceptibility or tendency | Not a blocking-susceptibility method | ASTM's public scope says D3354 measures existing blocking and is not intended to measure susceptibility | If blocking tendency is the decision, select an applicable method such as current ISO 11502 and record its exposure basis |
| Cross-standard boundary | ASTM states D1894 is not equivalent to ISO 8295 and the results cannot be directly compared | ASTM states D3354 is similar to ISO 11502 Method B but not technically equivalent | No equivalence, equation, correction factor or shared acceptance limit is inferred |
| Evidence role | Buyer requirement, supplier specification, TDS typical value, lot result or independent report | Buyer requirement, supplier specification, conditioned-sample result, lot result or complaint record | Keep each record attached to its document revision, lot or roll scope and acceptance owner |
| Converter decision | Supports diagnosis of sliding at the identified film-to-film or film-to-machine interface | Supports diagnosis of ply opening or film-layer adhesion at the identified roll or stack condition | Validate the actual unwind, web path, bag opening or packing-line event with agreed pass criteria |
04 SELECTION SEQUENCE
Move from a broad comparison to an approvable decision.
Name the surface event first
Separate resistance during sliding from layers that must first pull apart. Record where the symptom occurs and which two surfaces are involved.
Choose the method for that question
Request static or kinetic COF, existing blocking load or conditioned blocking tendency as separate evidence. Preserve the current standard, specimen state and original output.
Approve the roll and line decision separately
Set buyer-owned criteria for each selected test, then confirm roll opening, transport and conversion on the representative material and equipment path.
05 RFQ INPUTS
Film COF and blocking RFQ checklist
Request two controlled evidence rows when both sliding and layer adhesion matter. Unknown values stay open, and no method result is derived from another.
Open the RFQ brief builder ↗- 01
Packed product, package format, conversion step, observed symptom and the purchasing or qualification decision
- 02
Exact film or laminate construction, grade or document identifier and total specimen stage
- 03
Side A / Side B map showing treatment, print, coating, seal, inside, outside and unwind orientation where applicable
- 04
Event classification: starting friction, sliding friction, existing film-to-film blocking, blocking tendency or representative line behaviour
- 05
Exact current standard and edition selected for each result, plus the responsible laboratory's applicability statement
- 06
ASTM D1894 static coefficient, kinetic coefficient or both, with the tested surface pair and original report basis
- 07
ASTM D3354 existing blocking-load result only when that is the selected question; do not label it susceptibility
- 08
ISO 11502 qualitative or quantitative blocking-tendency context only when selected, with the exposure and specimen basis reported by the laboratory
- 09
Lot, roll, cross-web and machine-direction sample location plus specimen preparation and sampling record
- 10
Production, winding, packing, opening, conditioning and test dates; storage, temperature, pressure and contact history where relevant
- 11
Additive, coating, print, treatment, lamination and surface-contamination state when disclosed and relevant
- 12
Original output, unit, statistic, variability, raw-record reference and any below-range or method-limitation statement
- 13
Buyer requirement, supplier specification, TDS typical value, lot COA, independent report and complaint sample kept as separate evidence roles
- 14
Separate COF and blocking comparators, acceptance owner, retest rule, nonconformance disposition and change-control trigger
- 15
Representative unwind, bag-opening, feeding or packing-line trial with roll identity, settings, observations and finished-pack criteria
06 EVIDENCE BOUNDARY
Keep COF and blocking evidence tied to its method, source and approval owner
ASTM D1894-24 covers static and kinetic friction for an identified surface pair; its results are not directly comparable with ISO 8295:1995. ASTM D3354-21 measures existing blocking load rather than susceptibility and is not technically equivalent to ISO 11502 Method B, which addresses blocking tendency after a defined contact history. The ASTM and ISO standard-owner links govern current methods and editions, while Ampacet provides additive and film-surface background only. LayerSource structures the comparison; attribution for each cited procedure, value, product result and capability stays with the originating publication and supplier, keeping it separate from any LayerSource grade, additive, film, test, laboratory, production or converting capability. The buyer, supplier, converter and responsible laboratory select the licensed methods, identify specimens and surfaces, and approve each criterion independently.
07 BUYER QUESTIONS
Resolve the assumptions that make quotes diverge.
01Are film COF and blocking the same property?+
No. ASTM D1894 concerns resistance to starting and continued sliding between identified surfaces. ASTM D3354 concerns the load associated with separating film layers that already exhibit unwanted adhesion. Keep the methods, outputs and acceptance decisions separate.
02Does ASTM D3354 measure susceptibility to blocking?+
No. ASTM's public scope explicitly says the method measures the degree of existing blocking and is not intended to measure susceptibility. If the decision concerns blocking tendency after a controlled contact history, the responsible parties should select an applicable current method such as ISO 11502 and retain its exact basis.
03Does lower COF prove lower blocking?+
No. Slip and antiblock choices can interact with the same film surfaces, but a COF result does not replace a blocking result. Film construction, sides, age, additives, storage and contact history must remain attached to each separate test and line decision.
04Can ASTM D1894 and ISO 8295 COF values be compared directly?+
No. ASTM D1894-24 states that it is not equivalent to ISO 8295:1995 and that results cannot be directly compared. Do not convert or normalize the results into one acceptance row.
05Is ASTM D3354 equivalent to ISO 11502 Method B?+
No. ASTM's public scope says D3354 is similar to ISO 11502 Method B but is not technically equivalent. Preserve the exact selected standard, edition, specimen history, output and acceptance rule.
06What should a supplier enquiry request when a roll both sticks and feeds poorly?+
Request separate COF and blocking evidence, each tied to the exact film sides, lot or roll, sample age, conditioning, storage and current method. Then describe the actual roll-opening and machine-path symptoms and define a representative trial.