《Bonding Low Surface Energy Materials Using Adhesive Tape Solutions from Tecman》：
Topics Covered
Introduction
Surface Energy
Adhesion to LSE Substrates
Rubber PSA
Acrylic PSA
Tecman’s PSA Tapes
Conclusion
About Tecman Speciality Materials
Introduction
The attraction between molecules of dissimilar materials forms the principle of adhesion. For strong bonding with a substrate, an adhesive needs to ‘wet out’ the substrate by flowing across the substrate surface. This increases the surface area of the adhesive, thereby enabling it to achieve optimum bond strength.
The surface energy of a substrate is used to determine the adhesion strength. High surface energy supports adhesion and allows the liquid droplet to wet out to the surface (Figure 1). Figure 2 illustrates a low surface energy (LSE) and the liquid droplet is adhering to itself instead of the solid surface.
Figure 1. This image shows a High Surface Energy that supports adhesion and the droplet of liquid is wetting out to the surface.
Figure 2. This image shows a low surface energy and the droplet is clinging to itself rather than the solid surface.
Surface Energy
Knowing the surface energy of a substrate at an early stage is helpful in order to achieve a successful bonding solution, though most material manufacturers will not reveal the surface energy values of their materials. The unit of surface energy is dynes/cm.
A contact angle measuring device is typically used in order to measure the surface energy of a substrate. However, this approach is not feasible in a typical production environment. As a result, surface energy measurements are more commonly performed by applying a dyne solution to a material surface. Table 1 summarizes typical surface energies in dynes/cm.
Table 1. Typical surface energies (dynes/cm).
High
Medium
Low
Material
Surface Energy
Material
Surface Energy
Material
Surface Energy
Copper
1,103
Kapton
50
PVA
37
Aluminium
840
Nylon
46
Polystyrene
36
Stainless Steel
700-1100
Polycarbonate
46
Acetal
36
Lead
458
Polyester
43
Polypropylene
29
Glass
250 – 500
Polyurethane
43
Silicone
22-24
ABS
42
Teflon
18
PVC
42
Acrylic
38
Adhesion to LSE Substrates
Knowing the dyne level of a substrate is crucial in the selection of an appropriate bonding solution, especially considering the widespread adoption of LSE engineering plastics in several fields.
Pressure Sensitive Adhesive (PSA) technologies which are capable of forming a strong bond with LSE substrates are the subject of intense research. Consulting an adhesive application engineer during the design stage of a project involving adhesion is highly recommended.Tecman Speciality Materials provide design engineers with the technical support and knowledge in order to select the appropriate adhesive product.
One approach of forming adhesion to a LSE substrate is the application of a surface treatment process in order to improve the substrate’s surface energy. The surface can be treated either mechanically, by corona or plasma treatment, or chemically. Many different chemical treatments are available.
Choosing an appropriate surface treatment is beneficial in many ways. It allows the use of a wide variety of PSAs in an application, thereby providing more adhesive options for design engineers in terms of cost and performance.
In areas where surface treatment is not feasible, the required adhesion performance can be achieved by selecting an LSE compatible adhesive. The presence of additional polymers in the core construction of this adhesive provides superior a adhesion to LSE substrates. Rubber based adhesives such as solvent rubber and hot-melt rubber exhibit better adhesion performance with LSE substrates. However, they have their own drawbacks which hinder their selection.
Rubber PSA
The following are the advantages of a typical rubber PSA:
Forms a strong bond with LES substrates
Provides superior adhesion to porous or uneven surfaces
Soft adhesive wets out to the surface rapidly for quick adhesion build up
Very high initial bond (high tack) up to 80% of total bond strength on contact
Economical
The following are the drawbacks of a typical rubber PSA:
Lack of cohesive strength as it is soft adhesive, thus providing low shear adhesion values
Low temperature resistance
Poor resistance to chemicals, acids and alkalis
Not suitable for external environments as it has little or no resistance to UV light
Acrylic PSA
In its natural state, pure acrylic PSA will not adhere to LSE substrates and requires a surface treatment. Blending special tackifier additives into the pure acrylic PSA construction can address this problem. Compared to rubber-based PSAs, modified acrylic PSAs deliver superior adhesion performance.
The following are the key advantages of a typical pure acrylic PSA:
Hard adhesive exhibits superior shear properties and good cohesive strength
Very high ultimate bond
High temperature resistance (up to 280? for short term)
Superior UV resistance
Superior resistance to chemicals and solvents
The shortcomings of a typical pure acrylic PSA are as follows:
Inferior adhesion to LSE substrates
Hard adhesive provides slow wet-out
Low initial tack with down to 20% of bond strength on contact
Expensive
Modified acrylic adhesives, consisting of carefully selected additives, offer the advantages of both rubber and acrylic adhesives. It is recommended to get the advice of an application engineer when selecting a suitable bonding solution because not all modified acrylic adhesives will form a strong bond with LSE substrates.
Tecman’s PSA Tapes
Tecman offer a variety of PSA tapes, such as film tapes, transfer adhesives, and Very High Performance Bond (Vhpb) tapes, for adhesion to LSE substrates. Table 2 lists the range of adhesive tapes offered by Tecman for bonding LSE substrates.
Table 2. Tecman’s range of adhesive tape for bonding LSE substrates.
Product Ref:
Adhesive Type
Carrier Type
Thickness (mm)
Temperature Resistance
Colour
11-TR10
Modified LSE Acrylic
N/A
0.065
120°C
Clear
12-TS02
Solvent Rubber
Tissue
0.130
70°C
Hazy
13-FL02
Modified LSE Acrylic
uPVC
0.220
70°C
Clear
13-FL03
Modified LSE Acrylic
PVC
0.310
70°C
White
15-Vhpb06
LSE Vhpb
Foamed Acrylic
0.640
120°C
Grey
15-Vhpb07
LSE Vhpb
Foamed Acrylic
1.140
120°C
Grey
Conclusion
Adhesive tapes are increasingly used in design and engineering projects. Application engineers at Tecman recommend adhesive tapes to bond LSE substrates. Adhesive tapes are lightweight, clean and provide quick adhesion. They are cost effective, invisible and spread stress uniformly. They can tolerate vibration and movement, and eliminate structural weak points and investment in machinery.
About Tecman Speciality Materials
Tecman Speciality Materials is a leading adhesive tape converter specialising in bonding, fastening, cushioning and insulating, sealing, masking and protection applications, part of an International Group supplying self- adhesive solutions to manufacturers across the global.
Tecman has advanced manufacturing capabilities in both the UK and USA, manufacturing a diverse range of gaskets, seals and insulators, focusing on improving manufacturing efficiency, reducing assembly process time and unit costs.
《Bonding Low Surface Energy Materials Using Adhesive Tape Solutions from Tecman》：
Topics Covered
Introduction
Surface Energy
Adhesion to LSE Substrates
Rubber PSA
Acrylic PSA
Tecman’s PSA Tapes
Conclusion
About Tecman Speciality Materials
Introduction
The attraction between molecules of dissimilar materials forms the principle of adhesion. For strong bonding with a substrate, an adhesive needs to ‘wet out’ the substrate by flowing across the substrate surface. This increases the surface area of the adhesive, thereby enabling it to achieve optimum bond strength.
The surface energy of a substrate is used to determine the adhesion strength. High surface energy supports adhesion and allows the liquid droplet to wet out to the surface (Figure 1). Figure 2 illustrates a low surface energy (LSE) and the liquid droplet is adhering to itself instead of the solid surface.
Figure 1. This image shows a High Surface Energy that supports adhesion and the droplet of liquid is wetting out to the surface.
Figure 2. This image shows a low surface energy and the droplet is clinging to itself rather than the solid surface.
Surface Energy
Knowing the surface energy of a substrate at an early stage is helpful in order to achieve a successful bonding solution, though most material manufacturers will not reveal the surface energy values of their materials. The unit of surface energy is dynes/cm.
A contact angle measuring device is typically used in order to measure the surface energy of a substrate. However, this approach is not feasible in a typical production environment. As a result, surface energy measurements are more commonly performed by applying a dyne solution to a material surface. Table 1 summarizes typical surface energies in dynes/cm.
Table 1. Typical surface energies (dynes/cm).
Adhesion to LSE Substrates
Knowing the dyne level of a substrate is crucial in the selection of an appropriate bonding solution, especially considering the widespread adoption of LSE engineering plastics in several fields.
Pressure Sensitive Adhesive (PSA) technologies which are capable of forming a strong bond with LSE substrates are the subject of intense research. Consulting an adhesive application engineer during the design stage of a project involving adhesion is highly recommended.Tecman Speciality Materials provide design engineers with the technical support and knowledge in order to select the appropriate adhesive product.
One approach of forming adhesion to a LSE substrate is the application of a surface treatment process in order to improve the substrate’s surface energy. The surface can be treated either mechanically, by corona or plasma treatment, or chemically. Many different chemical treatments are available.
Choosing an appropriate surface treatment is beneficial in many ways. It allows the use of a wide variety of PSAs in an application, thereby providing more adhesive options for design engineers in terms of cost and performance.
In areas where surface treatment is not feasible, the required adhesion performance can be achieved by selecting an LSE compatible adhesive. The presence of additional polymers in the core construction of this adhesive provides superior a adhesion to LSE substrates. Rubber based adhesives such as solvent rubber and hot-melt rubber exhibit better adhesion performance with LSE substrates. However, they have their own drawbacks which hinder their selection.
Rubber PSA
The following are the advantages of a typical rubber PSA:
The following are the drawbacks of a typical rubber PSA:
Acrylic PSA
In its natural state, pure acrylic PSA will not adhere to LSE substrates and requires a surface treatment. Blending special tackifier additives into the pure acrylic PSA construction can address this problem. Compared to rubber-based PSAs, modified acrylic PSAs deliver superior adhesion performance.
The following are the key advantages of a typical pure acrylic PSA:
The shortcomings of a typical pure acrylic PSA are as follows:
Modified acrylic adhesives, consisting of carefully selected additives, offer the advantages of both rubber and acrylic adhesives. It is recommended to get the advice of an application engineer when selecting a suitable bonding solution because not all modified acrylic adhesives will form a strong bond with LSE substrates.
Tecman’s PSA Tapes
Tecman offer a variety of PSA tapes, such as film tapes, transfer adhesives, and Very High Performance Bond (Vhpb) tapes, for adhesion to LSE substrates. Table 2 lists the range of adhesive tapes offered by Tecman for bonding LSE substrates.
Table 2. Tecman’s range of adhesive tape for bonding LSE substrates.
Conclusion
Adhesive tapes are increasingly used in design and engineering projects. Application engineers at Tecman recommend adhesive tapes to bond LSE substrates. Adhesive tapes are lightweight, clean and provide quick adhesion. They are cost effective, invisible and spread stress uniformly. They can tolerate vibration and movement, and eliminate structural weak points and investment in machinery.
About Tecman Speciality Materials
Tecman Speciality Materials is a leading adhesive tape converter specialising in bonding, fastening, cushioning and insulating, sealing, masking and protection applications, part of an International Group supplying self- adhesive solutions to manufacturers across the global.
Tecman has advanced manufacturing capabilities in both the UK and USA, manufacturing a diverse range of gaskets, seals and insulators, focusing on improving manufacturing efficiency, reducing assembly process time and unit costs.