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| General Questions |
| Q. |
What is acrylic foam tape? |
| A. |
3M™ Acrylic Foam Tape is a high performance attachment system for all types of body side moldings and other exterior trim parts. This double coated tape combines high performance acrylic adhesives with viscoelastic acrylic foam cores to create products with unsurpassed initial adhesion, adhesion build, and the ability to dissipate the stresses associated with most automotive applications. 3M™ Acrylic Foam Tape satisfies all OEM specifications for attaching exterior trim components and conforms to all QS9000 requirements. |
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| Q. |
Why does acrylic foam tape only come in white and gray? |
| A. |
The process used to cure the unique polymers of the acrylic core is inhibited or slowed with the addition of color. Therefore a black acrylic foam tape (AFT) can not be made without significant sacrifices in properties. |
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| Q. |
Why do I need the thickness of a foam tape? |
| A. |
The thickness of the foam core allows the tape to compensate for surface mismatch between two surfaces. This is most important between two rigid materials. In the case of the acrylic foam tape, the core adds properties such as stress relaxation, plastisizer resistance and enhanced conformability. |
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| Q. |
Why doesn’t the tape feel sticky? |
| A. |
The higher performing acrylic adhesives are firm and dry to the touch. They are designed to bond to materials other than skin. The soft, rubber based adhesive of a band aid will feel sticky (thumb appeal), but has little holding power or performance properties needed to bond two components together. |
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| Q. |
What is the difference between the tape used to attach body side moldings and weatherstrips? |
| A. |
The tapes used to attach body side moldings have a pressure sensitive adhesive on both sides of the product. Because of the surface characteristics of the rubber weatherstrip, tapes used for weatherstrip attachment use a heat bond adhesive to achieve the maximum bond strength to the rubber. |
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| Design Questions |
| Q. |
How much tape do I need for bonding a component? |
| A. |
As a general starting point, use a part weight to tape area ratio of 13-15 grams per square inch of tape. The exact amount of tape to use will often be affected by molding design. Materials with a high degree of thermal expansion and contraction will need more tape area. Also, higher modulus materials such as TPO should use more tape than low modulus materials such as flexible PVC. |
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| Q. |
What are the design tolerances for thickness and widths? |
| A. |
The thickness tolerance will vary depending on the thickness of the product. Consult the data page for the specific product for this information. Acrylic foam tapes have a width tolerance of + 0.015 inches (+ 0.38 mm). |
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| Processing Tape To Part Questions |
| Q. |
Why and when do you use an adhesion promoter? |
| A. |
An adhesion promoter or primer is a resin system in a solvent carrier that is used to alter the surface characteristics of a substrate. This alteration will enhance, or in some instances create a surface for bonding with a pressure sensitive adhesive. |
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| Q. |
What precautions should be taken when using a primer or adhesion promoter? |
| A. |
As a general comment, proper ventilation should be used to handle the solvents. Depending on the chemical formulation of the primer, the handling procedures will vary. Consult the primer’s data page and the material safety data sheet for proper procedures and precautions. |
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| Q. |
How long after a primer or adhesion promoter is applied can I put the tape on? |
| A. |
Generally the tape should be applied when the primer is completely dry. If properly applied the drying time is generally 30—45 seconds. However the exact time required will vary depending on the primer formulation. This is varied by more or less solvent in the mixture. Consult the specification pages of the specific primer for the exact time required to dry. |
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| Q. |
Does stretching the tape during application affect the performance? |
| A. |
When used on substrates that shrink after the tape is applied, it is necessary to pre-stretch the tape and liner at a measured and controlled rate with a Stretch Laminator. When the part shrinks the tape will shrink at the same rate. The tape should not be stretched more than 4%. It is best to avoid stretching the tape if possible. |
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| Q. |
Can I apply a strip of tape around a 90° corner? |
| A. |
In the cross web width direction, keeping the width changing direction at a constant rate, is usually not a problem. However, turning the tape around a corner in width direction, where the inside edge is changing at a different rate as the outside edge is a problem for the tape to conform and the liner to expand and contract. Gradual sweeps are possible. Sharp turns require a die cut part. |
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| Q. |
What is in-line slitting? |
| A. |
In-line slitting is a cost-effective method of applying two strips of narrow tape to a molding or weatherstrip. For example, if two strips of _" wide tape are needed on a molding, _" wide tape is purchased and slit in half on your production line prior to applying the tape to the molding. Purchasing one roll of _" wide tape is more cost effective than purchasing 2, _"rolls of tape. |
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| Q. |
Can these tapes be cut to shape? |
| A. |
Yes. The process involves adding a second liner and cutting the tape with either a steel rule flat bed cutter or a rotary cutting process. The weed should be removed promptly for acrylic foam and transfer tape products to avoid the re-bonding of the cut area. |
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| Q. |
Can the tape be applied over the gate bumps on the back
of my part? |
| A. |
Usually this is not a good practice. Although 3M foam tapes will compensate for minor surface irregularities, gate nibs tend to disrupt the match of the mating surfaces to cause a bridging of the bond area. This results in reduced surface bonding area and substandard applications. Therefore, gate areas should be trimmed flush with the part surface. |
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| Q. |
Can the tape be applied to my part before it is painted
and baked? |
| A. |
The limiting factor will be the tape liner’s ability to withstand elevated temperatures. Liners can take 220° F for 20 minutes at a maximum. Care should be exercised to ensure the liner is not removed or lifted during the painting process. Direct soaking of the tape area with paint should be avoided. Please contact your 3M sales representative for information on high temperature liners that are under development. |
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| Splicing Questions |
| Q. |
Your product comes to us with splices in the rolls. Can I get splice free rolls? Can I sell our part if it contains a section of tape that has one of your factory splices? |
| A. |
Due to our manufacturing process, we cannot provide you with cost effective, splice free rolls of tape. Any splice made in our factory is a functional splice. That is, you should be able to apply the tape to your part and ultimately remove the liner from the part without the splice affecting this functionality.
Factory Splices (PDF, 15Kb) |
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| Processing Part To Vehicle Questions |
| Q. |
How can I get the liner off the tape easier? |
| A. |
The use of a tab is the most commonly used method to allow for easy liner removal. The options are:
- Liner as a tab—use of kiss cut die cutting to leave the liner extended over taped area.
- Adding on a secondary tape tab that is heat bonded to the liner in a secondary process
3M Tape 4230 (PDF, 14Kb).
- Same as #2 except using a pressure sensitive tabbing tape 3M Tape 4240 (PDF, 16Kb).
The most cost-effective method for easy liner removal is to use a wire brush to flick the liner off. This is done without any tabs.
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| Q. |
How far in advance can I remove the liner? |
| A. |
Exposing the functional adhesive to the open air has little effect in itself. However, air born contaminants will be attracted to the exposed adhesive and may reduce the performance. Therefore, the exposure time should be minimized. As a rule, the less chance for contamination or the less time the adhesive is exposed, the better the bond will be. |
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| Q. |
How much pressure is necessary for adhesion of a pressure sensitive attached component to ensure a good bond? How much time is the pressure required? |
| A. |
The goal is to pressurize to achieve 100% wet-out of the adhesive. This is affected by size, shape, flexibility and tape placement of the components to be bonded. As a rule, 30 PSI or a 15 lb. roller for 0.5" tape is used. More flexible components may need less pressure. The time factor is determined by the component flex, more than needs of the adhesive. The time is determined by the ability to flex the part such as to achieve 100% wet-out. |
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| Q. |
What do you mean by "wet-out"? |
| A. |
Wet-out is simply physical contact between the adhesive surface and the bonding surface. 100% wet-out can only be achieved from a properly designed part which is properly pressurized to the bonding surface. Technically, two types of wet-out exist, visual or macroscopic wet-out and microscopic. Only the visual wet-out can be controlled in a plant. The microscopic wet-out is time and temperature related and is a function of the adhesive chemistry and the physical and chemical properties of the bonding surface. Bond strength increases with time partly because microscopic wet-out increases with time. |
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| Q. |
You recommend heat for application. . . Is your tape a heat cure system? How much heat is needed? |
| A. |
Acrylic foam tape is not a “heat cure system" rather a “pressure sensitive" system. Therefore heat is not required to insure the tape performs as intended. As stated earlier, pressure is required. However heating can be beneficial in terms of making the trim component more flexible which improves wet-out. It is recommended that part temperature be 60-110° F. |
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| Q. |
The part is not adhering to the vehicle—What might be wrong? |
| A. |
In most cases the adhesive is not at fault. Items to review:
- Surface match—are the two surfaces to be bonded a good match?
- Check the back of the component for flatness.
- Check for surface contamination.
- Check for proper pressure and wet-out.
- Check process.
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| Q. |
Can I reposition a PS component once it is applied? |
| A. |
If a part is positioned with slight spot pressure, it can easily by de-bonded and repositioned. If full pressurization takes place, it will be more difficult to remove and may disrupt the adhesive enough to require part replacement. If the part has been applied and a good deal of time has elapsed, it will be most difficult to remove and usually will require part replacement. |
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| Q. |
Should I press the components together or roll them down? |
| A. |
Depending on the flexibility of the components it is generally better to pressurize parts with a rolling pressure keeping the rolling direction the same for multiple passes. A press fixture may have to be used in some cases. To avoid air entrapment behind the adhesive, pressure pads can be angled to simulate a rolling action. |
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| Q. |
How can I get the part off after it has been applied? |
| A. |
In general this is difficult to do unless removed shortly after application. The part should be heated to soften the adhesive and peeled to cut apart. Heavy residue can be removed with a hot knife and adhesive residue can be removed with a 3M™ Scotch-Brite™ Tape Removal Disc or solvent adhesive remover. |
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| Performance Questions |
| Q. |
What percent of the final bond strength can I expect immediately after application? After 20 minutes? After 72 hours? |
| A. |
Immediately after an application is made, about 30% of the bond strength is achieved. As the adhesive continues to wet-out the surface you can expect bond to be at 50% after 20 minutes. After 72 hours, about 90% of the bond strength is achieved. The bond will continue to build over time. |
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| Q. |
If the molding edge starts to fail, will the failure propagate? |
| A. |
The stress relaxation of the acrylic core will dissipate the stress on the part. Unlike other tapes, this will resist the propagation of a partial failure. |
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| Q. |
With two strips of tape on a BSM, won’t water get behind the molding and freeze, forcing the part off the car? |
| A. |
The gradual forces that may be encountered in the worse case of water entrapment are usually compensated for with the stress relaxation properties of the acrylic core. In most cases, water has room to expand without any effect on the tape bonding system. |
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| Q. |
How does the tape performance change at high temperature vs. low temperature? |
| A. |
As the temperature goes up, the adhesive and core of the tape soften. If pulled or stressed at elevated temperatures you would see lower peel values and higher conformability. At low temperature, the tape system is more rigid. This would give higher peel values and lessen conformability and lower shock resistance. All performance values return as the temperature returns to normal. |
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| Q. |
What is the highest temperature your tape can take and
still perform? |
| A. |
All of the exterior tape products will take the paint repair bake of 250° F for 30 minutes and maintain the bond. |
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| Q. |
Is the tape solvent resistant? |
| A. |
Yes, 3M tapes are resistant to most common automotive solvents like gasoline, diesel fuel, washer solvent, etc. Solvent resistance is a function of type of solvent, time of exposure and temperature. |
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