Transparent Polyimide Tape (Colorless PI Tape / CPI Film Tape / Clear Heat

Product Specification

1. Product Overview

Nomay Transparent Polyimide Tape is a single-sided adhesive tape combining colorless PI or high-transparency polyimide film with transparent silicone or acrylic pressure-sensitive adhesive.

Common names include colorless PI tape, CPI film tape and clear heat-resistant tape. Colorless grades are selected where low color tint is required; other transparent PI grades may retain a slight tint.

The product family supports visual alignment, component inspection, display and camera-module process protection, FPC insulation and custom die-cut adhesive parts.

Low-haze, low-yellowing and other optical-performance versions can be specified according to the customer's application. Performance must be evaluated on the complete adhesive tape, rather than the uncoated film alone.

2. Product Construction

Backing Material: Colorless PI or high-transparency polyimide film
Adhesive: Transparent silicone or acrylic pressure-sensitive adhesive
Adhesive Side: Single-sided
Appearance: Colorless or slightly tinted transparent, depending on the selected grade
Release Liner: Optional, according to handling and converting requirements
Formats: Slit rolls, liner-backed rolls, adhesive sheets, strips and custom die-cut parts

Finished tape thickness consists of the PI backing, adhesive and any additional functional coating. A removable release liner is excluded unless specifically stated.

A clear adhesive does not automatically make the finished construction optically clear. Film grade, adhesive coating, particles, bubbles and surface condition can all affect visibility.

3. Key Features and Buyer Benefits

Visibility During Assembly
The transparent construction allows selected alignment marks, component edges and protected areas to remain visible, subject to the required contrast and viewing conditions.

Low-Color-Tint Options
Colorless or low-yellowing grades can be selected where amber PI would interfere with visual inspection or appearance requirements.

Low-Haze Options
Selected constructions can be evaluated where scattering or image clarity matters. Define the required haze and transmission targets before selection.

Heat-Resistant Process Protection
Appropriate film and adhesive combinations can be evaluated for thermal processing where transparency must be retained.

Thin Electrical Insulation
The PI backing can provide a dielectric layer in selected electronic assemblies. Confirm the electrical performance of the finished tape.

Precision Converting
Slit rolls, adhesive windows, frames, strips and other die-cut shapes support repeatable positioning and assembly.

4. Film and Adhesive Selection

Colorless and High-Transparency PI
Select the film grade by light transmittance, haze, color tint, dimensional stability and thermal requirements. Transparent appearance does not establish suitability for every optical system.

Silicone Adhesive
Selected silicone constructions can be evaluated for temporary process protection and thermal masking. Confirm adhesion, optical change, residue and compatibility with the component.

Acrylic Adhesive
Selected acrylic constructions can be evaluated for permanent attachment, insulation and applications requiring different adhesive chemistry. Temperature limits and removal behavior depend on the selected adhesive grade.

Silicone-Sensitive Applications
Where contamination affects later coating or bonding, assess the complete tape, release liner and converting process. Acrylic chemistry alone does not establish a completely silicone-free product.

5. Reference Specifications and Customization

Backing Thickness: Industry reference range of 12.5–50 µm (0.0125–0.050 mm) for selected colorless PI film grades. This is film-selection guidance, not confirmation of Nomay stock or a finished-tape specification.

Total Thickness: Confirm the selected PI backing plus adhesive coating and any additional functional layer. Specify the required finished thickness and tolerance. Release liner thickness is stated separately.

Width: Custom slit widths, subject to film-grade availability, coating quality, winding conditions and dimensional tolerance.

Roll Length: Confirmed according to film thickness, adhesive construction, width and winding requirements. Specify finished-roll and master-roll requirements separately.

Adhesive: Transparent silicone or acrylic pressure-sensitive adhesive, selected according to the application.

Peel Adhesion: Confirm for the selected adhesive, substrate, dwell time and test method.

Optical Properties: Specify finished-tape transmittance, haze, yellowness and allowable changes after processing. Refractive index or birefringence requirements can be evaluated where relevant to the optical system.

Temperature: Confirm continuous operating temperature, peak process temperature, exposure time and heating cycles for the complete tape.

Supply Formats: Slit rolls, liner-backed rolls, adhesive sheets, strips and custom die-cut parts.

Nomay will confirm the compatible combination of film, adhesive, thickness, dimensions, liner and performance requirements before quotation.

6. Optical Performance and Custom Options

Transmittance
Specify whether the requirement concerns total visible-light transmission or transmission at particular wavelengths. State specimen thickness, measurement method and whether the tape is tested alone or bonded to a substrate.

Haze
Define the acceptable haze level for the finished adhesive construction. Clear appearance alone does not establish a specific haze value.

Yellowness and Color Change
Specify initial color and allowable change after heating, aging or other processing. Low initial yellowness does not guarantee no yellowing under every condition.

Image and Sensor Compatibility
For camera, display or polarized-light applications, evaluate the complete optical stack where relevant, including distortion, scattering, reflections and birefringence.

Post-Process Optical Retention
Check clarity, haze and color after the actual heating and cooling cycle. Physical survival of the film does not prove that optical performance remains acceptable.

Special Versions
Low-haze, low-yellowing and specified optical-cleanliness constructions can be evaluated on request. If ESD control is also required, specify and verify that function separately.

7. Application Industries

• Display and touch-panel assembly

• Camera and sensor-module assembly

• FPC and electronic-component manufacturing

• Optical-component assembly

• Industrial identification and process-label protection

• Selected semiconductor back-end assembly

• Precision die-cut converting

Select the finished construction against the actual process, optical target, adhesive compatibility and cleanliness requirements.

8. Application Scenarios

Display Alignment
For selected positioning or protection tasks where alignment marks must remain visible. Confirm contrast, haze, dimensional change, adhesive compatibility and removal requirements.

Camera-Module Process Protection
For selected temporary protection or positioning around camera and sensor assemblies. Use directly in an imaging path requires additional optical qualification; the tape is not automatically a lens protector or an optically clear bonding adhesive.

FPC Insulation and Protection
For selected dielectric separation, positioning and process protection. Confirm electrical performance, bending requirements and adhesive behavior. Pressure-sensitive PI tape is not automatically a substitute for an adhesive coverlay or circuit substrate.

Barcode and Process-Label Protection
For protecting selected identification areas while retaining readability. Test the actual printed label, substrate, scanner and process conditions. The tape is not automatically printable or qualified as a semiconductor process label.

Transparent Die-Cut Windows and Frames
For adhesive shapes requiring visibility or localized protection. Confirm whether the optical path passes through tape material or through an open aperture, and evaluate the assembled geometry accordingly.

Selected Semiconductor Back-End Tasks
For localized protection or identification needs after validating particles, contamination, outgassing and thermal behavior. Wafer processing, dicing and die attachment require separately qualified materials.

9. Thermal, Adhesion and Electrical Performance

Temperature
Transparent PI films and adhesives have grade-specific thermal behavior. Confirm the finished tape's temperature and exposure duration against adhesion, optical change, shrinkage and residue requirements.

Do not apply a film's glass-transition temperature or heat-resistance figure directly as the tape's continuous service rating. Silicone and acrylic constructions require separate specifications.

Peel Adhesion
Define substrate, specimen width, peel angle, speed, dwell time, conditioning and temperature. Permanent attachment and temporary removal may require different adhesive constructions.

Removal and Residue
Evaluate removal after the complete process. Transparent appearance does not guarantee residue-free peeling or compatibility with sensitive surfaces.

Electrical Insulation
Confirm breakdown voltage, leakage or other required electrical properties for the finished construction. Film data alone does not establish the performance of the adhesive tape or assembled insulation system.

Cleanliness
Where relevant, define allowable particles, ionic contamination, outgassing, adhesive transfer and release-liner contamination before product selection.

10. Application and Validation Procedure

Step 1: Identify whether the priority is general visibility, machine-readable marks, optical performance, insulation or temporary protection.

Step 2: Define transmittance, haze, color and any post-process optical limits.

Step 3: Select the film and adhesive against substrate, temperature, removal and contamination requirements.

Step 4: Confirm backing thickness, finished thickness, width, length and liner or die-cut format.

Step 5: Clean and dry the surface using a compatible method. Apply with uniform pressure while avoiding particles, wrinkles, trapped air and stretching.

Step 6: Run the actual thermal, chemical and handling process.

Step 7: Verify visibility, optical properties, dimensional stability, adhesion, electrical performance and removal behavior as applicable before mass production.

11. Comparison and Selection Guide

Transparent PI vs. Amber PI
Choose transparent PI where the required visibility or color response cannot be achieved with amber PI. Amber PI can still assist general visual placement where its tint is acceptable.

Colorless vs. High-Transparency PI
Choose by measured haze, transmission, color and thermal behavior rather than the name alone.

Transparent PI vs. Transparent PET
Compare the complete constructions against optical, thermal, electrical and adhesive requirements. Transparent PET parameters must not be copied to transparent PI.

Silicone vs. Acrylic Adhesive
Select according to the actual temperature profile, bonding surface, service life, removal and contamination requirements.

Tape vs. Optical Bonding Adhesive
A transparent pressure-sensitive PI tape has a film carrier and is not automatically interchangeable with OCA, LOCA or a protective cover-window material.

12. Send Your Application Requirements

For product selection, sample evaluation and quotation, please provide:

• Application, component and bonding substrate

• General visibility or defined optical-performance requirement

• Light-transmittance target and wavelength range

• Haze, yellowness and allowable post-process changes

• Refractive-index or birefringence requirements, if relevant

• Silicone or acrylic adhesive preference

• Temporary protection or permanent attachment requirement

• Continuous temperature, peak temperature, exposure time and heating cycles

• Backing thickness, finished thickness and tolerances

• Width and finished-roll or master-roll length

• Liner, adhesive-sheet or die-cut drawing requirements

• Peel adhesion, removal method and residue limits

• Electrical-insulation requirements

• Cleanliness, particle and outgassing requirements

• Order quantity and destination country

• Any required testing or certification standard

Nomay will confirm the suitable film and adhesive construction, optical and technical specification, sample requirements, minimum order quantity and quotation. Required testing or certification can be arranged according to the agreed model, standard and completion requirements.