P-THERM® Thermal Interface Materials Selection Guide

As electronic device designs become more compact and in demand, manufacturers are finding more of a need to provide thermal management solutions for their products. Choosing the right materials to efficiently cool devices may result in sending a blockbuster product to market that sets sales records and makes a name for your company. On the other hand, the wrong thermal management material can lead to major issues within the manufacturing process, operational and durability difficulties, delays in getting to market, and reduced customer satisfaction.

Since 1998, Polymer Science has been designing and innovating thermal management solutions for manufacturers and suppliers. Our diverse team of highly skilled and experienced engineers, technical staff, and designers work directly with OEM and Tier 1 suppliers to identify your needs, understand your process, and create a customized solution that moves your project forward.

P-THERM® Thermal Management Materials for Electronic Device Cooling

In our P-THERM® Selection Guide, you’ll take a deep dive into all of Polymer Science’s P-THERM® thermal management solutions, including:

  • Gap filler materials designed to achieve desired heat management properties to keep components at optimized operating temperatures
  • Thermally conductive phase-change materials that perform like thermal grease with the convenience of a thermal pad.
  • Heat spreaders that allow for quick dissipation of heat in the X-Y direction
  • Tapes and adhesives that offer reliable adhesion and conductive properties across a wide temperature range
  • ECIs that offer good dielectric and thermally conductive properties without the worry of flow from wax-based products or the mess associated with thermal grease.

All of our P-THERM® products are designed to efficiently and effectively aid heat conduction in ways that meet the growing requirements of today’s advanced electronic designs. Below is a preview of what you’ll find in the P-THERM® Selection Guide, which will help you learn more about how Polymer Science can help with your next product or project. For a more in-depth look, download the full P-THERM® Selection Guide.

Why Working with Polymer Science Gives OEMs an Advantage

After working for more than 25 years with OEMs and Tier 1 suppliers in the consumer electronics, lighting, automotive, aerospace, electric vehicle, and other industries, we at Polymer Science have developed a proven five-step methodology for building custom solutions that take customer projects from conception to commercialization quickly and efficiently.

Our customers not only bring their products to market in record time, but they also deliver reliable and high-quality devices that consumers love. And it’s that kind of performance that gives our customers a distinct advantage over their competitors. Here is how we do it.

  1. Define the Project: In the initial stage of project development, our sales team works directly with you to gather information, define the scope of the project, and establish clear design criteria.
  2. Design & Assess: During this phase, your team collaborates with our engineering team to develop and, if necessary, modify the original solution to ensure you get the best product possible with product and manufacturing feasibility.
  3. Verification & Validation: Once a plan is designed and approved, we determine the reproducibility and repetition of the manufacturing process to determine whether the solution is sound and ready for production.
  4. Commercialization: Development is now complete and implementation is in the works. We now transferred your project to our highly skilled sales and operations teams for commercialization.
  5. Aftermarket Support: With help from our technical services, engineering, and quality assurance teams, we continue to work with you to ensure that our material continues to meet the form, fit, and function demands necessary for the success of your product.

Thermal Properties and Test Methods

A key to any successful project is working early in the design and planning stages. When you clearly define the criteria, Polymer Science’s team can help you determine the ideal materials. We are able to provide clear data and provide test methods. When you need custom solutions, our testing capabilities can quickly guide your planning and design.

Durometer Testing: This test measures the depth of an indentation in the material created by a given force on a standardized indentor point. That depth is dependent on the hardness of the material, its viscoelastic properties, the shape of the presser foot, and the duration of the test. ASTM 2240 durometers allow for a measurement of the initial hardness or the indentation hardness after a given period of time. 

In a basic test, force is applied in a consistent manner, perpendicular to the surface being tested without shock, and measuring the hardness (depth of the indentation). If a timed hardness is desired, force is applied for the required time and then read.

P-THERM® gap fillers range in hardness including soft, ultrasoft and hypersoft to suit your application and the final design.

Thermal Resistance – Standard: Thermal resistance is a heat property or a measurement of a temperature difference by which an object or material resists a heat flow. Thermal resistance is the inverse of thermal conductivity. For gap fillers, thermal adhesives, heat spreaders and phase change materials, this information is key. 

Rt = (T2- T1) / Q • A = L / k

Rt = Thermal Resistance (K m2 / W)

T1 = Cooling Plate Temperature (K)

T2 = Heater Temperature(K)

Q = Heat Flow (W)

A = Area of the Compressed Specimen (m2)

L = Thickness of Specimen (m)

k = Thermal Conductivity (W/m K)

Thermal Conductivity – Modified: To improve the accuracy of TIM measurements and to increase the measurement precision, Polymer Science uses modifications to ASTM D5470 testing. 

k = t2 – t1 / Rt2 – Rt1

k = Thermal Conductivity (W/m K)

T1 = Thickness of Specimen 1 (m)

T2 = Thickness of Specimen 2 (m)

(t2 > t1)

Rt1 = Thermal Resistance of Specimen 1 (K m2/W)

Rt2 = Thermal Resistance of Specimen 2 (K m2/W)

Compression Force: ASTM D575 test method A is a procedure for determining the compression-deflection of rubber compounds (except hard rubber and sponge rubber). ASTM D575 test method A is a compression test in which the force required to cause a specified deflection is determined. Deflection can be described as the change in thickness of the specimen upon application of a compressive force. 

Get the Complete P-THERM® Selection Guide

When you download our P-THERM® Selection Guide, you’ll get a comprehensive look at Polymer Science’s line of gap fillers, phase change materials, heat spreaders, electronic control interfaces, and adhesives. You’ll also find additional information specifications, information, and reference material, such as what’s provided below.  

Frequently Asked Questions

What is the difference between thermal conductivity and thermal impedance?

Thermal impedance is the sum of the thermal resistance of the material as well as the contact resistance at each interface at a given compression. Thermal impedance takes into account all forms of resistance of heat flow including the thickness of the TIM, surface irregularities or smoothness, and area of the component. Thermal conductivity is a bulk property of the material and good for general comparisons, but thermal impedance is better to use for simulating the heat transfer efficiency of the system.

What characteristics should be considered when choosing a P-THERM® gap filler?

The two functional characteristics of a gap filler used to determine how effective it will work in your application are thermal conductivity, which is the bulk property associated with the rate of heat transfer across a gap of a given length, and resistance, which is the gap filler has at each of the planar interfaces. This resistance may be a result of incomplete wetting of the surface by the gap filler as well as air gaps or voids in between the gap filler and the heat sink or heat source. These resistance sources may be a result of surface roughness or stepped faces in the application. In addition to thermal conductivity, durometer, and conformability of the gap filler mitigates interfacial resistance.

Can a pressure-sensitive adhesive be added to the P-THERM® Gap Filler?

The typical configuration of the material does not include a pressure-sensitive adhesive, but can be added if mechanical anchorage is not present in the design or securement of the pad to the device is required. The gap pad can be supplied with an adhesive or an adhesive that will adhere to silicone can be utilized to provide an adhesive layer to the construction.

When should P-THERM® heat spreaders be used?

Heat spreaders are specifically designed to transfer heat in the x-y plane or spread the heat from a generation point across a larger surface area. They are used when thin profile, high heat applications such as high temperature LED or high heat generating components of smaller handheld devices need to be dispersed for protection of the component or the user of a device.

Which P-THERM® gap filler is right for my application?

Gap fillers are available in a variety of bulk thermal conductivities, hardness, and compression profiles. Polymer Science recommends a minimum of 20% compression for gap filler products. To determine the best gap-filler product for the application, the gap to be filled, the amount of heat or rate of heat that needs to be transferred, and the amount of compression force deflection which can be withstood by the components in the application should be understood. Compression force deflection profiles as well as thermal impedance vs compression data is available for all P-THERM® gap filler products upon request.

Frequently Used Terms

Breakdown Voltage: The voltage required to cause a failure through an insulator when tested using a specific set of conditions

Corona Discharge: A partial discharge within an insulator by ionization of the air within or on a contact surface

Dielectric Strength: For a pure electrically insulating material, the maximum electric field that the material can withstand under ideal conditions without undergoing electrical breakdown and becoming electrically conductive

MBLT: Minimum bondline thickness; when two substrates obtain the closest possible distance under pressure

Pressure Sensitive Adhesive (PSA): A type of non-reactive adhesive which forms a bond when pressure is applied to bond the adhesive with the adherend

Thermal Contact Resistance (Ri): The resistance to the flow of heat from air, or other contaminants, trapped between the irregularities of the contacting solid surfaces

Viscoelastic Material: The property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like honey, resist shear flow and strain linearly with time when stress is applied. Common types of these materials are referred to as “plastics.”

Our P-THERM® Selection Guide which includes additional FAQs and Glossary Terms.