Why Choose A Solvent Acrylic PSA?

The Benefits

Solvent acrylic PSAs are the adhesives of choice for durability and long-term applications; they provide the widest range of expedient performance properties, including better chemical, water and heat resistance over almost all other adhesive types.

The molecular structure of an adhesive determines the way in which it performs in different circumstances. Solvent-based acrylic adhesives feature a number of crosslinking mechanisms, whereas water-based adhesives typically do not. One such effect of crosslinking is an increased resistance to chemicals and other solvents; most water-based adhesives lack this connective ability, resulting in them being more susceptible to poor end-use performance when exposed to solvents.

Through testing and modifications, adhesive technologists are able to use solvent acrylic adhesives to deliver precise polymer performances to meet almost all adhesive needs. This wide breadth of possibility in customisation of solvent acrylic adhesives enables the option of combining positive characteristics with minimal sacrifice to overall performance properties.

Advantages of using formulated/customised solvent acrylic adhesives include:

  • Outstanding chemical resistance

Well-suited for use in environments where chemical exposure is a possibility.

  • Performance properties retained at a wide range of temperature extremes

This adhesive type performs well at high and low temperature extremes, making it well suited to being used in a diverse scope of locations and conditions.

  • Longevity and durability

Solvent acrylic adhesives are usually the best option for an application that requires long-term wear and durability against the elements.

Things To Consider

Tack Level

Tack is the measure of force required to remove an adhesive tape from a substrate immediately after initial application, with very minimal effort. Solvent acrylic PSAs’ tack levels can be manipulated to range from low, to medium, to high tack.

Skin Adhesion

Skin adhesion is measured through testing the bond strength between the adhesive and the substrate. Pressure is applied to the adhesive and is then left to wet-out onto the substrate (adhesive dwell). Adhesion generally continues to increase for a period of time after the initial application, typically 24 hours. For this reason, a peel test, in which adhesion is tested through the force required to ‘peel’ the adhesive from the substrate, is often performed at different periods of time to show any differentiation.

Solvent acrylic PSAs are suitable for use in the medical industry where skin contact is required; many also meet ISO10933 test standards.

Biocompatibility ISO10933 Test

A series of tests designed to provide assurance that the materials used in the manufacture of a medical device are appropriate and safe for use.

The type of testing performed on the material/adhesive is determined by the intended use, duration of contact on the skin and the condition of the intended patient.

The ISO guidance documents for biocompatibility ISO 10993, offer the direction needed to determine which test methods are most appropriate.

Colour

The clear appearance of a solvent acrylic PSA is well suited to medical requirements.

Substrate

Solvent acrylic PSAs can be applied to a variety of substrates, including PU films, polyester films, non-woven carriers, PET & PP scrims, foams and papers.

MVTR

Moisture vapour transmission rate (MVTR) is a measure of the passage of water vapour through a substance; it is an incredibly important factor to be considered in order to control moisture levels in a wound dressing. The higher the MVTR reading, the more moisture that can pass through the adhesive.

A number of solvent acrylic PSAs have high MVTR ratings, making them ideal adhesives to be used in the construction of a wound dressing as they enable moisture from the wound to escape.

Solvent Acrylic PSAs are both gamma and EtO sterilisation stable:

Gamma sterilisation stable

The substance is exposed to gamma rays as a method of sterilisation or decontamination. The gamma rays are a form of electromagnetic radiation of very short-wave lengths; these rays act as a source of ionising energy that destroys bacteria and pests.

EtO sterilisation stable

Ethylene oxide (EtO) is a gas that acts as a powerful alkylating agent. The sterilisation process disrupts the DNA of microorganisms, preventing them from reproducing, therefore destroying all known viruses, bacteria and fungi and insuring safe, sterile products.

The process of EtO sterilisation consists of four primary variables: gas concentration, humidity, temperature and time. The substance is first brought to the necessary temperature and moisture content, it is then placed in an enclosed chamber where all air is removed and controlled amounts of steam and EtO are introduced.  The final stage requires the substance to enter a high velocity aeration room, where gas residuals are lowered to the required levels for a period of at least 48 hours.

Thickness

The coat weight thickness is dependent on the solid content, viscosity and end use of the solvent acrylic adhesive system; on average coat weights range from 10-100gsm.

Selecting The Right Manufacturer

With customers requesting complex combinations of performance characteristics, it is important that the manufacturer understands the properties of the adhesive and has broad experience of the application of an adhesive onto a substrate.

The manufacturer is also required to have a knowledgeable technical team who have experience in handling solvent acrylic PSAs; understanding where to source the adhesive, how to laminate the construction, how to coat and how to dry. All of the adhesive’s characteristics can be lost if just one step in the process is done incorrectly, highlighting the importance of choosing the right manufacturer to build your construction.

For information on how Raleigh can support you in your solvent acrylic PSA coating requirements, contact our team on 01785 850 357 or email our Business Development Manager, Julian Watkins.

 

Why perforation is important in silicone gel wound dressings

There is a drive in the wound care industry to constantly improve the performance of a wound dressing; we have found that perforation in silicone gel wound dressings plays a very important part in this development.

It is already recognised that silicone gel wound dressings show improved performance over more conventional wound dressings in the following areas:

  • Immobilisation of the wound
  • Prevention of contamination
  • Reduction in the risk of bacterial infection
  • Absorption of any drainage of wound exudate
  • Oxygen entry and water vapor escape
  • Atraumatic removal
  • Cosmetic covering

The action of perforating a silicone gel dressing further improves performance. To realise these improvements, manufacturers need to understand the following 5 factors that can maximise the effectiveness of a perforated wound dressing:

  1. Open Areas

Accuracy in meeting design requirements of perforation in silicone gel wound dressings during the manufacturing process is vital in allowing wounds to heal at the required rate; this is achieved by ensuring that the perforation pattern reaches an open area of 17%-20%.

This percentage range allows exudate to be drawn away from the wound into the absorbent level, whilst maintaining moisture levels of the wound surface at the required rate for optimal healing.

  1. Perforated Hole Size

Not only is the open area of the perforation pattern important, but manufacturers must also understand the importance of achieving precise cuts and consistent hole size in the perforation pattern. This is critical because it ensures that the exudate is removed, leaving the blood to carry on with the healing process.

To achieve this consistency in hole size, expert manufacturing tooling is used to cut each hole cleanly, removing debris to ensure the perforated product functions with 100% efficiency.

  1. Pattern of Perforation

Consistency of quality throughout the wound dressing construction is important to ensure performance parameters are achieved. This is evident in the perforation pattern, which should feature a consistent pattern throughout all the dressing.

Keeping to this standard enables maximum yield and repeatability, guaranteeing that the same high level of performance is achieved with every individual wound dressing

  1. Perforation Quality

Expert coaters for the wound dressing marketplace will always take into careful consideration the choice of carrier for the dressing, so as to avoid any complications or impinge on the ability to perforate the substrate, factors which would result in an inferior dressing.

Only through the use of the highest quality materials and through production in an ISO 14644 class 7 clean room environment will manufacturers be able to produce the highest medical grade dressings for the healthcare market.

  1. Waste Removal

During the manufacturing process of precision perforation, it is vital that waste created by the perforation process is removed.

Any perforator should be able to remove 99%+ of all waste produced during the perforation process. This careful extraction minimises the risk of any waste ending up in the wound itself. This process also enables the perforated sections to remove exudate from the wound consistently.

Meeting Medical Grade Standards with Raleigh Coatings 

High quality raw materials, precision perforation and clean room coating & conversion environments are vital for superior silicone gel wound dressings. As market leaders in silicone gel coating, Raleigh Coatings are committed to the whole process, ensuring the final finished product delivered to customers meets the demanding specifications required.

For more information about the coating and conversion options that Raleigh can support you in, contact our team on 01785 850 357 or email our Business Development Manager, Julian Watkins.

Silicone gel coating for the healthcare sector

Here at Raleigh Coatings, we understand that when it comes to the healthcare sector, it’s imperative that our productions always meet the high standards required by our clients.

That’s why we aim for flexibility and an adaptable approach when it comes to silicone gel coating for the healthcare sector.

Our approach is always to work in partnership with you and your objectives to produce a specialist bespoke development of your own personalised construction.

Flexibility and support every step of the way

Following careful discussions and analysis of your specifications, the process takes place through our experienced technical team who will use either a bi-laminate or tri-laminate formation as the starting point.

Throughout all stages of the process, from development to completion, our technical team will always be on hand to offer advice and guidance; communicating our progress and making necessary adaptations to meet your needs.

During the process, many of our clients are reassured to know that any element of the construction can be altered to suit the end application of the project, reducing costly issues and saving time during the final phase.

Within the process, the following variables will require consideration and will be inspected by expert technicians:

  • Gel type
  • Supplier of gel
  • Levels of tack of gel
  • Gel coat weight

Of course, Raleigh Coatings understands that each subtle difference in the construction of your wound dressing alters the characteristics of the final product; from the ease of peel of the release liner, to the length of time the dressing will adhere to the skin.

So with our astute attention to detail and by using our in-depth knowledge of the processes and outcomes of coating with silicone gel, we will ensure that even the slightest of changes are factored into use and resulting outcomes. This is done in order to achieve the desired final results as agreed by your specifications.

Further to our precision in development of specialist gel coatings, we also offer class 7 clean room coating facilities that guarantee your end product meets the stringent industry standards of ISO 14644.

Which elements in the construction of your wound dressing can we alter?

To meet the needs of your final wound dressing requirements, the following elements can be adjusted by Raleigh Coatings technicians;

PU (Polyurethane) Films

The thickness, flexibility and type of PU films can each be fine tuned to suit your specific needs, resulting in a variety of end results including transparency, strength or breathable compositions. {Check for accuracy/examples.

Release Liners

To achieve different release characteristics, the type and surface texture of the release liner (which is in contact with the gel) can be varied making them suitable for a range of end applications.

Acrylic Types

Acrylic adhesives are used in tri-laminate constructions to bond to either the absorbent pad or to bond to the other substrates within the wound dressing construction.

Acrylics can be flood coated (where the whole substrate is coated), or stripe coated (where there is a stripe void of adhesive/pattern) to suit.

When working with us to create your own bespoke product, it is useful to give consideration to certain areas such as; the coat weight required to achieve the targeted adhesion levels; considerations into the medical compatibility of the adhesive; the ideal substrate for the acrylic to bond to and levels of tack and the peel performance required. We are, of course, able to help and offer advice with all of these decisions.

Raleigh Coatings are here to help you every step of the way in creating your own personalised construction, by working exactly to your necessary requirements and standards.

For further information on our silicone gel coating capabilities please visit our page on Specialist Medical Adhesive Coaters.

To contact our team please call 01785 850 357 or email our Business Development Manager, Julian Watkins.

 

Solving your coating challenge is our business

At Raleigh Coatings, we thrive on helping customers realise the potential of their most ambitious ideas.

Our technical team is trained and experienced in dealing with all enquiries, no matter how unusual they may seem and no matter what size the request.

Our customers come to us from a range of industries interested in our ability to produce exceptional quality coatings; including medical tape, graphic film and specialist labels.

However, our most exciting challenges come from novel coating ideas that need to be produced with completely new formats.

How we meet your bespoke coating requirements

Bespoke custom coating is our chance to really shine and defines us as industry leaders.

By utilising state-of-the-art technologies and unrivalled expertise, we are able to break down the complexities of the process; with the aim of making the coating understandable and goals achievable.

Starting with the initial enquiry, we will talk with you about your vision and end goals, understanding your needs and concerns. Then we take your concept and develop it through the expertise of our technical team in a specially equipped laboratory.

The construction is then trialled through a pilot line to test, inspect and adjust to achieve the right results. Following approval of the process, the product is then transferred and produced as a finished coated product on the main line.

The end result? The realisation that your innovative idea is now a reality.

New coating techniques are not just the only solutions we provide for our customers. Here’s a sample of questions that can help you decide if Raleigh Coatings is the match you’ve been looking for.

Do you only coat adhesives?

No, we can also coat with any solvent based coating. We also offer silicone gel coating services using our clean room based line.

I’m struggling with ideas for which substrates / carriers to use?

Simply talk to us. We are happy to help. We have a broad experience working with non-wovens, films (polyester, polypropylene, polyurethane) and a variety of papers. Using our experience with these materials we can help guide you through the selection process.

What if my substrate requires higher surface energy?

We have a vast experience with chemically treated films and can also corona treat inline onsite; both of which are used to promote adhesion to substrates.

What if my product requires coating in class 7 clean room environment?

Then you’re in luck. We have 2 clean room coating lines that meet the ISO 14644 class 7 requirements for both acrylic and silicone gel coating.

My product requires onward conversion / slitting, can you help?

Yes we can, by using our reel to reel slitting facilities. This means that we can take your jumbo rolls and cut them down to narrow width rolls.

Do you have further conversion services?

Yes, we also have partnerships with product conversion companies so that we can fully satisfy all your conversion needs.

How can you advise and assist with silicone gel coating for wound care products?

As the UK’s leading specialist in medical adhesive coatings, we have developed a strong expertise in exacting the conditions that silicone gel coating requires. We also have very strong relationships with key gel manufacturing suppliers that support our ability to provide accurate and specialist advice when it comes to wound care product coatings.

Do you only flood coat?

No, we also offer stripe coating of acrylic P.S.A.

Can I vary my coat weights?

Yes, we can flood coat from 10gsm – 100gsm in acrylic P.S.A and also from 50gsm – 500gsm in silicone gel.

Our commitment to providing solutions for your most complex coating requirements is evident not only in our approach, but our reputation as unrivalled technical experts in the field of custom coating. 

For further queries it may be helpful to visit our frequently asked question6 page, or contact our team by calling 01785 850 375 or email our Business Development Manager, Julian Watkins at [email protected].