Wednesday, November 24, 2010

Using PC-120 cleaner / Conditioner

PC-120 is generally used when there is a need for increased durability in the bonding application.

One of the little known qualities of PC-120 is that it not only improves the durability of key Plexus products but can also improve the durability performance of the special metal bonders MA830 and MA832.

PC-120 works by cleaning the surface of contamination using Isopropyl Alcohol (IPA) as a solvent to lift machining oils and other contaminants from the surface of the metal then leaving a thin phosphate based coating to retard surface corrosion.
To tell which areas have been primed, PC-120 leaves a pink colour on the surface.  PC-120 can be brushed, wiped or sprayed onto the surface and can be wiped clean with a dry rag to leave a thin quick drying film.

Application tips!
1. Do not use too much PC-120 – Only a very thin coat is needed you should only see a very faint pink colour on the metal.
2. Do not use dirty or oily rags to apply PC-120 – Dirty rags will put contaminants onto the surface rather than removing them.
3. Remove any corrosion – Abrade any surface corrosion before applying the PC-120
4. Check the shelf life – Product which has exceeded its expiry date will not perform in specification.
5. Close the bottle – Open bottles allow the solvent to evaporate.

Tuesday, June 29, 2010

Understanding Methacrylate Technology

Plexus adhesives are methacrylate adhesives that have been developed to perform under a wide range of conditions. This is achieved by improving curing, bonding, adhesion and toughening mechanisms.

The free radical cure mechanism of Plexus methacrylates is catalytic in nature.  When the adhesive and activators are mixed, amines in the adhesive cause the peroxide to decompose into free radicals, which initiate the process of chain polymerisation of the MMA to PMMA.  These reactions are exothermic and take place at room temperature removing the need for applying heat to initiate the cure.

The improved adhesion mechanism of methacrylate adhesives consists of the low viscosity monomer solvating the surface of most thermoplastics prior to the curing mechanism beginning. The monomer can solvate most surface contaminants which removes the need for any surface preparation prior to applying the adhesive.

Plexus methacrylate adhesives have a unique combination of polymers and impact modifiers which enable them to be strong yet flexible. The resulting high tensile strength along with impressive elongation (over 100% at @ 30o C) gives them the processing advantages and convenience of epoxies and polyurethanes

The total combination of all these factors along with good rheology, thixotropic properties, ease of use and lack of VOC’s and solvents, results in a range of structural methacrylate adhesives that can be successfully used in the marine, construction and automotive markets on a wide range of substrates.

Thursday, April 22, 2010

Structurally Green

A current factor that affects industry is the Environment and the impact that industry has on it. The word ‘green’ refers to the Environment and the efforts in reducing or eliminating harmful by-products, emissions and waste.

So, who measures ‘green’?
Obviously there are independent organizations such as Government agencies (e.g. HSE), industry groups like BASA and Greenguard Environment Institute (GEI). There are also the customers and the manufacturers.

A Methylmethacrylate (MMA) is a two component, structural adhesive. They provide an alternative for traditional assembly methods. In terms of ‘green’ MMAs offer several advantages:
• Low VOC emissions
• Less than 0.5% VOCs
• No Off-gassing issues
• Safe for indoor and closed locations
• Recyclability

MMAs eliminate toxins to the greatest extent possible. Products are developed with as much focus on human health as on the performance and this reduces the hazardous or toxic materials considerably. Unlike traditional assembly methods MMAs offer regrindability.

Friday, March 12, 2010

Product Review: MA685

Plexus MA685 is an optically clear, two-part methacrylate adhesive that is designed for solid surface and assembly where a visible line is undesirable.

The MA685 characteristics:
• Working time – 8-11 minutes
• Fixture time – 20-25 minutes
• Ratio – 10:1

The adhesive has the capability to bond small gaps of 0.3 mm to larger gaps.

MA685 has excellent resistance to:
• Water
• Impact
• Scuffing
• High temperatures
• UV light

Tuesday, March 02, 2010

What are MMAs?

• MMA stands for Methylmethacrylate

• A Methylmethacrylate is a type of structural adhesive that provides a balance of high tensile, shear and peel strengths. They are able to resist impact, shock and stress across a wide temperature range.
• They are two component materials (adhesive + activator) that react when mixed together. This reaction is exothermic.
• MMAs have controlled cure speeds that range from fast (4 minutes) to very slow (210 minutes). They are also tolerant to off-ratio mixing.
• MMAs are generally used to bond plastics, composites and metals.
• ITW Plexus have a wide range of MMA structural adhesives to suit many needs.