MAXI-BOND MB-250
SEMI-RIGID MULTI PLASTIC REPAIR CLEAR
Technical Data Sheet | rev. 1/2014
Product Description
MAXI-BOND 250 is a two-component, room temperature curing, black coloured, odourless, thixotropic polyurethane adhesive specially designed for structural bonding of a wide range of materials including thermosetting and thermoplastic materials, steel, aluminum, concrete, wood, and glass.
Product Data
| PROPERTIES | COMPONENT A | COMPONENT B | MIXED |
|---|---|---|---|
| Chemical base | Polyol | MDI | Polyurethane |
| Mixing ratio by volume | 1,00 | 1,00 | |
| Mixing ratio by weight | 0,86 | 1,00 | |
| Colour | Black | Straw | Black |
| Appearance | Liquid | Liquid | Thixotropic |
| Viscosity (mPa•s) | 950 | 2.800 | 40.000 |
| Relative density | 1,00 | 1,16 | 1,08 |
| Application temperature (°C) | +10/+30 | ||
| Working time | 5 min | ||
| Bonding time | 15 min | ||
| Fully cured time | 480 min | ||
| Temperature of exothermic reaction (°C) | 50 | ||
| Hardness (Shore) | 40 D | ||
| Elongation (%) | 140% | ||
| Service Temperature (°C) | -40/+90 | ||
| Shelf life (month) | 12 | ||
| Storage temperature (°C) | +20/+30 | ||
Processing
The strength and durability of bonded joints depend on proper pre-treatment of the surfaces to be bonded. At the very least, joint surfaces should be cleaned with a good degreasing agent to remove all traces of dust, dirt, oil, and grease.
Pre-treatment of thermoplastics materials such as PVC, polycarbonate, polypropylene, PMMA, etc., can be made using a mixture of light ethers or with isopropanol. Use of strong solvents is not recommended due to the risk of damage to the plastic surface.
Pre-treatment of other surfaces can be made using acetone or trichloroethylene. Petrol or other solvents should never be used.
Where possible, carry out mechanical abrasion to remove paint from the surfaces (where necessary) and to increase strength and resistance of the adhesion. Let the pre-treated area dry before applying the adhesive.
Product Application
MAXI-BOND 250 is available in bi-component cartridges (side by side), or in several sizes of drums. Blending should be made through a static mixer composed of a minimum of 16 elements. A lower number of components does not allow complete mixing. A higher number of components would increase the speed of the chemical reaction of hardening. Static mixers are disposable.
Bi-component cartridges can be used through manual applicators or specific pneumatic tools, depending on capacity and cartridge shape.
For process and continuous applications, automatic dosing systems for low viscosity materials can be used. Based on specific needs, MAXI-BOND technical service is available to offer advice for the correct machinery to use with specific requirements.
The mixture must be applied directly from the mixer onto the pre-treated dry surface. The optimal layer of adhesive that will guarantee the highest resistance for the joint should be at least 0.5 mm thick. The components have to be assembled before the adhesive starts curing and sealed with steady pressure all over the gluing area.
Reaction Mechanism
The speed of the hardening reaction is mainly influenced by two factors: the application temperature and the application thickness. Being the reaction exothermic, the speed decreases as the thickness and temperature application increase.
Even if to a lesser extent, the substrate influences the speed of reaction. Materials with a high coefficient of thermal conductivity will tend to slow down the reaction.
The maximal temperature of the reaction will be reached with a 5 mm application thickness and is always lower than 50°C.
Diagram: Reaction speed vs application temperature (thickness 5 mm) A line graph shows the percentage of full strength over time (0-120 min) for applications at 0°C, 20°C, and 40°C. The 40°C application achieves full strength fastest, followed by 20°C, and then 0°C.
Diagram: Reaction speed vs application thickness (20 °C) A line graph shows the percentage of full strength over time (0-120 min) for applications with thicknesses of 0.2 mm, 1.0 mm, and 5.0 mm. The 0.2 mm application achieves full strength fastest, followed by 1.0 mm, and then 5.0 mm.
Diagram: Temperature curve of reaction for applications at 20 °C A line graph shows the temperature (°C) over time (0-24 min) for applications with thicknesses of 0.2 mm, 1.0 mm, and 5.0 mm. The 5.0 mm application shows the highest temperature peak (around 50°C), followed by 1.0 mm, and then 0.2 mm.
Technical Characteristics of Cured Product
The below properties have been measured through standard sample tests, made by bonding overlapping samples of different materials of dimensions 100 × 20 × 20 mm with an adhesion area of 20 x 20 mm. The values, obtained with standard methods on typical lots, are exclusively provided as technical information, and not as product specification. In any case, it will be up to the user to test the product for a specific situation and then give his final approval.
Diagram: Average lap shear strength vs temperature hardening 24 h at 20 °C A line graph shows the percentage of full strength versus hardening temperature (°C) from -60°C to 120°C. The strength remains high (near 100%) across a broad range, approximately from -40°C to 80°C.
Physical Properties at 20 °C
| Property | Value |
|---|---|
| Tensile strength (N/mm²) | 20 |
| Resistivity (Ω·cm) | 1,8x10¹⁴ |
| Dielectric constant εr | 3,1 |
| Dielectric strength (kV/mm) | 22 |
| Thermal conductivity (W/m·K) | 0,20 |
Performance Data
Diagram: Average lap shear strength (N/mm²) with various substrates A bar chart displays lap shear strength (0-15 N/mm²) for different substrates: Wood, Glass, Marble, Concrete, Brass, Copper, Steel, and Aluminium. Steel and Aluminium show the highest strength (around 10-12 N/mm²), while Wood, Glass, Marble, and Concrete show lower strengths (5-8 N/mm²).
Diagram: Average lap shear strengths (N/mm²) with plastic materials A bar chart displays lap shear strength (0-15 N/mm²) for various plastic materials: PVC, EPDM, Polyamide, PMMA, Polypropylene, ABS, Polycarbonate, and SMC. Polycarbonate and SMC show the highest strengths (around 10-12 N/mm²), with other plastics showing values between 5-10 N/mm².
Diagram: Average lap shear strengths (N/mm²) vs ageing to chemical agents A bar chart shows lap shear strength (0-15 N/mm²) after immersion in various chemical agents. Strength is retained for Water at 60°C, Paraffin, and Motor oil. However, Methylethylketone, Acetic acid, Isopropanol, Ethyl Acetate, Petrol, and Battery acid result in "Destroyed" or very low strength.
Diagram: Average lap shear strengths (N/mm²) vs thermal ageing A bar chart shows lap shear strength (0-15 N/mm²) after thermal ageing for 30, 60, and 90 days at 60°C. The strength remains consistent across all ageing periods, indicating good thermal stability.
Product Storage
MAXI-BOND 250 has a shelf life of 12 months from the initial production, provided it is stored in a cool and dry place, between +20°C and +30°C. The expiry date is indicated on the label.
Once opened, the cartridges will last until the expiry date (as long as the above conditions are met), leaving the last mixer used onto the cartridge.
Product Handling Cautions
MAXI-BOND products are generally quite harmless to handle, provided that certain precautions are normally taken when handling chemicals.
The uncured materials must not be allowed to come into contact with foodstuffs or food utensils. Measures should be taken to prevent the uncured materials from coming into contact with the skin, as people with particularly sensitive skin may be affected.
The wearing of impervious rubber or plastic gloves will normally be necessary; likewise, the use of eye protection.
The skin should be thoroughly cleaned at the end of each working period by washing with soap and warm water. The use of solvents has to be avoided. Disposable paper should be used to dry the skin.
Adequate ventilation of the working area is recommended.
These precautions are described in greater detail in the safety data sheet for the individual products and should be referred to for further information.
Notes
The information and, in particular, the recommendations relating to the application and end-use of MAXI-BOND products, are given in good faith based on MAXI-BOND current knowledge and experience of the products when properly stored, handled, and applied under normal conditions.
MAXI-BOND cannot assume responsibility for the results obtained by others over whose methods we have no control.
It is the user's responsibility to determine suitability for the user's purpose of any production method mentioned herein and to adopt such precautions as may be advisable for the protection of property and of persons against any hazards that may be involved in the handling and use thereof.
MAXI-BOND specifically disclaims all warranties expressed or implied, including warranties of merchantability or fitness for a particular purpose, arising from sale or use of MAXI-BOND products. MAXI-BOND specifically disclaims any liability for consequential or incidental damages of any kind, including lost profits.
Users should always refer to the most recent issue of the technical data sheet for the product concerned, copies of which will be supplied on request.
