BOPP Film Technical Data Sheet: Properties & Specifications
Featured Technical Answer
This BOPP film technical data sheet defines the film-level properties that should be checked before clear, non-heat-sealable BOPP is used as a pressure-sensitive tape backing. It covers gauge consistency, MD/TD tensile strength and elongation, surface treatment, COF, haze, gloss, and thermal shrinkage, with the test conditions needed to interpret them. Reference values support comparison and incoming qualification; coating response, converting stability, and finished-tape behavior still require representative sample testing before production approval.
Qualification Boundary for Tape-Grade BOPP Backing
This technical data applies to clear, non-heat-sealable, tape-grade biaxially oriented polypropylene film used as the backing for pressure-sensitive tape conversion. Use it to compare film gauge, MD/TD properties, surface condition, optical quality, and heat-related dimensional change before coating or slitting.
The scope stops before finished-tape performance. Peel adhesion, initial tack, holding power, adhesive shear, residue observation, and carton sealing behavior belong to the coated construction. When the film is supplied as converter-scale coated material, the BOPP Jumbo Roll Tape range should be reviewed separately because adhesive system, coating weight, roll format, and downstream slitting introduce another set of variables.
Treated Face, Oriented Core, and Reverse Surface
A representative tape-backing construction can be read as treated surface – oriented polypropylene core – controlled reverse surface. Biaxial orientation produces different mechanical behavior in the machine direction (MD) and transverse direction (TD), so tensile strength, elongation, and shrinkage should not be reduced to one undirected value. The treated face should also be identified before wetting-tension checks, printing, priming, or adhesive-related trials.
Corona treatment improves wettability, but a dyne reading does not prove adhesive anchorage. If the film has aged, been contaminated, or experienced a different storage condition, recheck the treated face before a critical coating or printing trial.
Reference Property Window for Tape Conversion
The ranges below are qualification references synthesized from published tape-grade BOPP technical data. They are not OPALUS guaranteed production limits. Final acceptance should use project-confirmed grade data, agreed sampling rules, and equivalent test conditions.
| Item | Typical Value / Reference Range | Test Method or Condition | Notes |
|---|---|---|---|
| Material / film type | Clear, non-heat-sealable BOPP backing film | Grade identification | Actual layer formulation and additives are grade-dependent. |
| Nominal film thickness | Reference range 21-55 um | ASTM D6988 or qualified equivalent | Production gauge should be project-confirmed. |
| Thickness variation | Typical reference +/-3% | Cross-web gauge mapping | Check representative web positions, not only the center. |
| Density | Typical value approx. 0.905 g/cm3 | ASTM D1505 or equivalent | Reference value for clear tape-grade BOPP. |
| Surface wetting tension | Typical reference >=38 dyn/cm on treated side | ASTM D2578 or qualified dyne method | Indicates surface condition; does not prove adhesive anchorage. |
| Kinetic COF | Typical reference 0.35-0.45 | ASTM D1894; define surface pair | Affected by slip package, conditioning, dwell, and test speed. |
| Haze | Typical reference 1.0-2.2% | ASTM D1003 | Compare equivalent gauge and clean samples. |
| Gloss | Typical reference 92-97 at 45 deg | ASTM D2457 | Use the same tested surface and geometry. |
| Tensile strength – MD | Typical reference 118-157 MPa | ASTM D882; machine direction | Do not substitute for finished-tape breaking force. |
| Tensile strength – TD | Typical reference 245-304 MPa | ASTM D882; transverse direction | Direction must be verified before comparison. |
| Elongation at break – MD | Typical reference 150-210% | ASTM D882 | Read together with tensile strength and gauge. |
| Elongation at break – TD | Typical reference 30-80% | ASTM D882 | Compare only under equivalent specimen conditions. |
| Thermal shrinkage – MD / TD | MD 2.0-4.0%; TD 0.5-2.5% reference | 120 C / 5 min; ASTM D1204 or project method | Describes dimensional change, not finished-tape service temperature. |
| Surface-treatment retention | Project-confirmed value | Recheck after extended storage | Relevant when coating or printing depends on treatment level. |
What to Measure Before Coating or Slitting
A useful incoming program connects every test to a processing decision. It should also reflect the intended coating, slitting, and rewinding controls when a new gauge, film lot, adhesive route, drying profile, or line setting is introduced.
| Test Item | What It Checks | Suggested Method or Reference | Why It Matters | When To Request It |
|---|---|---|---|---|
| Thickness / cross-web gauge | Nominal gauge and local variation | ASTM D6988 or validated film gauge method | Gauge bands can affect coating, roll build, slitting, and finished thickness. | New grade or gauge; roll-build variation; incoming mismatch. |
| Tensile + elongation – MD/TD | Directional strength and deformation before break | ASTM D882 with direction, speed, specimen width, and conditioning recorded | Explains web handling and whether apparent lot differences are directional. | Grade change, repeated web breaks, or mechanical lot variation. |
| Wetting tension / treated side | Current surface condition and correct coating face | ASTM D2578 or equivalent; identify surface first | Low or aged treatment can change coating wet-out; the value alone does not prove anchorage. | Incoming treated film, extended storage, contamination, or printing/coating trial. |
| COF | Film-to-film sliding resistance | ASTM D1894; specify surface pair and speed | COF affects traction, blocking, unwind, and rewind stability. | Slipping, blocking, web wandering, or new additive package. |
| Haze / gloss | Optical uniformity and surface appearance | ASTM D1003 / D2457 or equivalents | Useful for transparent backing and lot-to-lot appearance control. | Unexpected cloudiness, appearance change, or optical specification. |
| Thermal dimensional change | MD/TD shrinkage under controlled heat | ASTM D1204 or project-approved equivalent with temperature and dwell recorded | Links laboratory data to drying, printing, or converting heat exposure. | Curl, width movement, registration change, or higher process temperature. |
| Visual / surface inspection | Wrinkles, gels, scratches, contamination, edge damage, flatness | Controlled internal inspection at representative web positions | Finds local defects that an average laboratory value can miss. | Incoming lot approval, transport damage, or recurring coating defect. |
| Representative conversion trial | Coating wet-out, web tracking, drying, slitting, and rewind response | Project trial using intended adhesive and line settings | Laboratory film data cannot fully reproduce full-width production behavior. | New film grade, new adhesive system, equipment change, or critical application. |
Reading Directional, Surface, and Optical Data Together
Thickness is not simply a stronger-is-better number. Higher gauge changes stiffness, yield, coating geometry, and roll build, while cross-web variation can create local hard or soft bands. Tensile strength and elongation should be interpreted as an MD/TD pair: a direction error during specimen preparation can make a normal film appear out of specification.
Surface treatment, COF, haze, and gloss answer different questions. Wetting tension describes surface condition for later processing; COF describes how defined surfaces slide; haze describes light scattering; gloss describes reflected appearance. None of these values independently predicts finished-tape adhesion. Thermal shrinkage must likewise be tied to a stated temperature and dwell time rather than converted into a generic service-temperature claim.
Where Base-Film Data Stop Predicting Tape Behavior
Glass, metal, plastics, painted or coated surfaces, rough substrates, and low-energy materials are evaluated only after adhesive coating. For finished transparent carton-sealing tape, substrate condition, adhesive chemistry, application pressure, and dwell time matter more than bare-film tensile data.
When synthetic-rubber hot-melt PSA is used, test the hot melt sealing tape construction separately for tack, peel, shear, and carton compatibility. Load, cargo geometry, transport, and operator variables belong to package validation, not the base-film specification.
Three-Stage Validation: Film, Conversion, Surface
Stage 1 verifies the film: gauge consistency, treated-side identity, surface wetting tension, MD/TD data, visible defects, and storage history. Stage 2 runs the intended coating, drying, slitting, and rewinding route and records web tracking, curl, bubbles, edge quality, blocking, slipping, film tearing, and rewind condition.
Stage 3 evaluates the completed tape on the intended substrate. Where sustained contact matters, inspect at 24 h, 72 h, and 7 days for peel behavior, edge lifting, adhesive trace, surface shadow, gloss change, bubbles, film tearing, and residue observation. Use consistent application pressure and removal conditions so samples are comparable; do not generalize one passing trial into a universal clean-removal claim.
When a Number Becomes a Process Risk
A data mismatch is most useful when it is connected to a probable failure mode and a specific recheck. Before rejecting a lot, confirm that film grade, gauge, direction, conditioning, sampling position, and test settings match the approved reference.
| Data Point | If Too Low | If Too High | Risk in Application | Check Before Full Use |
|---|---|---|---|---|
| Film thickness | Lower stiffness or weaker local backing contribution | Higher stiffness, lower yield, altered roll build | Web instability, tearing at thin bands, finished-gauge variation | Map left / center / right positions and confirm nominal gauge. |
| Cross-web thickness variation | Local thin bands | Local thick bands / hard bands | Uneven coating, wrinkles, telescoping, inconsistent slit rolls | Use cross-web mapping, not a center-only reading. |
| Wetting tension | Poorer coating or printing wet-out | Higher value is not proof of stronger anchorage | Coating voids, transfer, inconsistent ink or adhesive response | Verify treated side, film age, contamination, and actual coating trial. |
| Tensile strength – MD/TD | Greater sensitivity to web or edge stress | Unexpected stiffness or grade/orientation difference | Web breaks, edge splits, changed converting behavior | Confirm MD/TD direction, gauge, specimen geometry, and test speed. |
| Elongation – MD/TD | Less deformation before break | More stretch before rupture / orientation difference | Registration shift, stretch, or altered break behavior | Read with tensile data under the same specimen conditions. |
| Kinetic COF | Excessive slipping | Excess drag or blocking tendency | Web wandering, poor traction, unstable unwind / rewind | Retest the intended surface pair and line conditions. |
| Haze / gloss | Unexpected appearance shift | Unexpected appearance shift | Cloudiness or lot-to-lot visual mismatch | Compare clean, equivalent-gauge samples before and after coating. |
| Thermal shrinkage – MD/TD | Unexpected grade or thermal-history difference | Excess dimensional movement under heat | Curl, width movement, registration error, rewind instability | Repeat at the agreed temperature and dwell; compare with actual process heat. |
| Treatment after storage | Reduced current surface condition | Higher reading alone does not prove anchorage | Delayed coating or printing inconsistency | Recheck after extended storage and record temperature, humidity, sunlight, and wrapping condition. |
Protecting Surface Treatment and Roll Geometry in Storage
Keep film in stable indoor storage, protected from direct sunlight, condensation, contamination, and concentrated roll pressure. Around 23 C / 50% RH may be used as a laboratory conditioning reference; warehouse limits should follow the project-confirmed specification. Let temperature-conditioned rolls acclimatize before critical testing or coating.
Protect roll edges, cores, and web geometry during stacking and transport. Crushed edges, telescoping, damaged wrapping, moisture, or heat can create local defects that a center-strip test misses. Because corona-treated surfaces can change with age and handling, recheck the treated face when storage or transport history differs materially from the approved condition.
FAQ
How should a BOPP film technical data sheet be read?
Match each value with its test method, specimen direction, conditioning, and data status. MD/TD mechanics, wetting tension, COF, optics, and shrinkage should be compared under equivalent conditions, not as isolated numbers.
What is the difference between a typical value and a guaranteed value?
A typical value describes representative tested material. A guaranteed or project-confirmed specification requires defined acceptance limits, sampling rules, and agreed test conditions. Reference values should not be treated as universal production guarantees.
Why is sample testing needed if the film values are within range?
Because film data do not reproduce full-width coating and substrate interaction. A representative trial confirms that the approved film runs stably through conversion and that the completed tape behaves acceptably under the intended test condition.
Can tensile strength or elongation predict peel adhesion or holding power?
No. Tensile strength and elongation describe the BOPP backing; peel adhesion, initial tack, holding power, and adhesive shear describe the completed pressure-sensitive tape and must be measured separately.
Can storage conditions change BOPP film test results or coating response?
Yes. Extended storage, heat, humidity, sunlight, contamination, damaged wrapping, or roll pressure can change surface condition or roll geometry. Recheck affected properties before conversion.