Technical Bulletin March, 2009 3M Optically Clear Adhesive and 3M Contrast Enhancement Film General Description This bulletin describes the method of laminating rigid-to-flex or rigid-to-rigid surfaces using 3M Optically Clear Adhesive (OCA) or 3M Contrast Enhancement Film (CEF) for prototype purposes. The information presented in this bulletin should be considered representative or typical. The user is responsible for evaluating the lamination process under actual conditions of use and with the substrates intended for the customer application to determine specific process parameters necessary in the individual customer s application. Process Overview High quality rigid-to-rigid and rigid-to-flexible lamination requires special lamination equipment. Hand lamination is to be used only for proving concepts. The lamination process is described in detail in the next section. Substrates first need to be laminated together and inspected for entrapped air. If signs of air entrapment are observed, the laminate needs to be autoclaved to remove air. When one of the substrates is polycarbonate (PC) or Acrylic (PMMA), extra testing is required to ensure the plastic is not outgassing. Substrates such as PC and PMMA tend to absorb moisture and outgas when exposed to high temperature and high humidity, creating bubble defects in laminated parts. Plastics can be pre-baked to drive moisture out. Required Materials Clean room area Clean rubber roller Work Station (vacuum table or glass table) Wipes (avoid using wipes with free floating fibers), Air ionizer gun, Isopropyl alcohol 3M Polyester Tape 8403 (green tape) Cut to size samples of 3M Contrast Enhancement Film (CEF) and 3M Optically Clear Adhesive (OCA) Autoclave Temperature/Humidity Chamber 3
Process Description A brief description of lamination process is provided in the following table. Brief Summary of Lamination Process Pre-bake in dry, clean oven Temperature 85 C (for PMMA and PC only) Duration 2-5 hours Lamination Room Clean Room Temperature Room 24 C and above Autoclave Temperature 30-60 C Pressure Duration 70-100 PSI 20-60 minutes Durability Temperature 60 C Humidity Duration 90% R.H. 12-72 hours A comprehensive description of lamination process is provided in the following section. Step 1: Baking Step 1 applies only to plastic substrates (e.g. PC and PMMA). In order to drive moisture out of the plastic, bake the PC and/or PMMA. The oven has to be dry, clean, and free of volatiles. Samples can be baked at 85 C for 2-5 hours, depending on the plastic thickness; the thicker the plastic, the longer it takes to remove moisture. Step 2: Lamination 3M Optically Clear Adhesive (OCA) and 3M Contrast Enhancement Film (CEF) lamination must be done in a clean room to avoid contamination that will result in defects. Clean room class 10K or better is recommended. Temperature of 24 C and above is preferred. Make sure the substrates are clean and dry; free of dust and other contaminants. Isopropyl alcohol can be used to clean surfaces. Use ionizer gun if necessary before lamination to make sure the surface is clean. A. Secure the first substrate. Vacuum table can be used to hold the substrate down. In the absence of a vacuum table, 3M Polyester Tape 8403 (green tape) can be used at the corners to hold the sample in place. Make sure all the substrates are clean. Figure 1. Holding sample in place. (2)
Step 2: Lamination (continued) B. Use only properly die-cut pieces with clean edges so that you do not have excess adhesive or contaminant at the perimeter. 3M provides precision die cut 3M Contrast Enhancement Film (CEF) to customers specification design. C. Remove easy liner from 3M Optically Clear Adhesive (OCA) or 3M Contrast Enhancement Film (CEF) die cut. The easy liner is the first liner that is easily removable. D. Place a small piece of green tape on the short sides of die cut. Use another tape to remove the liner. This will help hold OCA/CEF without sticking to fingers. Figure 2. Removing easy release liner. E. Align and roll down OCA/CEF on first substrate using a roller, squeezing out the air. Roll down pressure should be moderate. Be careful not to break your substrate. Figure 3. Aligning the OCA/CEF. Figure 4. Rolling down the OCA/CEF. F. Remove the green tape tabs carefully without disturbing the release liner. (3)
Step 2: Lamination (continued) G. Remove the tight liner using green tape. Align and roll down the second substrate, squeezing the air out. Figure 5. Aligning the 2nd substrate for lamination. Figure 6. Completely laminated piece. Alternatively, for flat substrates, a simple heat laminator can be used. Heat laminator. Apply pressure and heat evenly across the sample. Use temperature above ambient for this process. Once lamination is complete, visually inspect the finished piece for any bubbles or entrapped air around the display frame. This completes the process if no bubbles or entrapped air are observed. For rigid-to-flexible lamination, the air gap around the display frame is less expected unless there is ink step/decoration on one or both of the substrates, in which case autoclave is required. Visually look for bubbles around the edge of ink line. If you observe signs of air gap or bubbles in the laminate, go to the next section. For rigid-to-rigid lamination, some air entrapment is to be expected and autoclave is highly recommended. If you observe signs of air gap or bubbles in the laminate, go to the next section. In most cases, vacuum lamination equipment minimizes and also eliminates the air bubble issue during lamination. (4)
Step 3: Autoclave The autoclave process works with heat and pressure to squeeze any remaining air out. The autoclave type must be dry. Typical autoclave conditions are outlined below. Temperature: Pressure: Duration: 30-60 C 70-100 PSI 20-60 minutes At this point the assembly process is complete for the part. Air bubbles Figure 7. Sample before autoclave process. (Overhead shadow, not a defect) Figure 8. Sample after autoclave process. Step 4: Durability This step is meant for customers who would like to determine the effect of long term device exposure to high temperature and high humidity. Most moisture absorbing substrates (e.g. PC and PMMA) fail this process because they outgas at high temperature and high humidity creating bubble in the assembly. Step 1 above is implemented to improve outgassing problem. Here is a typical accelerated process condition. Temperature: 60 C Humidity: 90% R. H. Duration: 12-72 hours (5)
3M Product Recommendation for Outgassing Substrates 3M Optically Clear Adhesive (OCA) 3M Optically Typical 180 Peel Transmittance % Clear Adhesive Thickness Liner Thickness Adhesion to Glass (Reflective Haze Refractive Product (mil) (2 mil) (oz./in.) Corrected) % Index 8171 1 2 42 > 99 0.6 1.47 8172 2 2 45 > 99 0.8 1.47 8173D* 3 2 41 > 99 1 1.47 8191 1 2 70 > 99 0.3 1.47 8192 2 2 94 > 99 0.3 1.47 8195 5 2 110 > 99 0.3 1.47 *Double coated OCA. 1mil OCA/1mil PET/1mil OCA 3M Optically Clear Adhesives 8171, 8172, and 8173D are good for polycarbonate (PC) and Acrylic (PMMA). 3M Optically Clear Adhesives 8191, 8192, and 8195 are good for Acrylic (PMMA). 3M Contrast Enhancement Film (CEF) 3M Contrast Typical 180 Peel Transmittance % Enhancement Film Thickness Liner Thickness Adhesion to Glass (Reflective Haze Refractive Product (mil) (2 mil) (oz./in.) Corrected) % Index CEF08A05 5 2 110 > 99 0.3 1.47 CEF08A07 7 2 115 > 99 0.3 1.47 3M Contrast Enhancement Films CEF08A05 and CEF08A07 are good for Acrylic (PMMA) (6)
Certification/Recognition MSDS: 3M has not prepared a MSDS for these products which are not subject to the MSDS requirements of the Occupational Safety and Health Administration s Hazard Communication Standard, 29 C.F.R. 1910.1200(b)(6)(v). When used under reasonable conditions or in accordance with the 3M directions for use, these products should not present a health and safety hazard. However, use or processing of the product in a manner not in accordance with the directions for use may affect their performance and present potential health and safety hazards. TSCA: These products are defined as articles under the Toxic Substances Control Act and therefore, are exempt from inventory listing requirements. RoHS: These products comply with the requirements of EU Directive 2002/95/EC and 2005/618/EC. For Additional Information To request additional product information or to arrange for sales assistance, call toll free 1-800-251-8634. Address correspondence to: 3M Electronics Markets Materials Division, Building 21-1W-10, 900 Bush Avenue, St. Paul, MN 55144-1000. Our fax number is 651-778-4244 or 1-877-369-2923. In Canada, phone: 1-800-364-3577. In Puerto Rico, phone: 1-787-750-3000. In Mexico, phone: 52-70-04-00. Important Notice All statements, technical information, and recommendations related to 3M s products are based on information believed to be reliable, but the accuracy or completeness is not guaranteed. Before using this product, you must evaluate it and determine if it is suitable for your intended application. You assume all risks and liability associated with such use. Any statements related to the product which are not contained in 3M s current publications, or any contrary statements contained on your purchase order shall have no force or effect unless expressly agreed upon, in writing, by an authorized officer of 3M. Warranty; Limited Remedy; Limited Liability. This product will be free from defects in material and manufacture at the time of purchase. 3M MAKES NO OTHER WARRANTIES INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. If this product is defective within the warranty period stated above, your exclusive remedy shall be, at 3M s option, to replace or repair the 3M product or refund the purchase price of the 3M product. Except where prohibited by law, 3M will not be liable for any indirect, special, incidental or consequential loss or damage arising from this 3M product, regardless of the legal theory asserted. 3 Electronics Markets Materials Division 3M Electronics 3M Center, Building 21-1W-10, 900 Bush Avenue St. Paul, MN 55144-1000 3M is a trademark of 3M Company. 3 1-800-251-8634 phone Please recycle. Printed in U.S.A. 651-778-4244 fax 3M 2009. All rights reserved. www.3m.com/electronics 60-5002-0371-0 (7)