Tecvac, Inc.

800 847-9324

"Taking Quality To A New Level...Worldwide"

Tecvac, Inc. Does Not Manufacture Or Sell Materials

But Applies A Vast Array Of Materials To A Vast Array Of Problems

Here Is A Brief Description Of The Flagship Products We Use With Our Processes

STRUCTURAL REPAIR MATERIAL

Methyl Methacrylate (MMA)

 

This is a 3 part, low viscosity, high strength material and was brought to market by Rohm and Haas Company in 1933; you might recognize the product name Plexiglass.

 

This low-molecular weight resin has been refined with special modifiers that are ideal for the vacuum injection crack repair processes. It is noted for its ultra low viscosity (5-15 cps) and its highly rated physical properties, flexibility, and its superior bonding and wetting properties.

 

Unlike epoxies, the material is not temperature sensitive (can be installed at -20degrees F.) and is easily mixed and modified by Tecvac Technicians for specific field conditions. An additional advantage over honey thick epoxies, is that MMA is favorably forgiving when not mixed “just right”; as you may know, improperly mixed expoxy will not cure; it will remain in a "goo-state" forever. Whereas, a pin-head of initiator in a 5 gallon bucket of MMA sets off an un-stoppable chain reaction and will cure. In that sense, it cannot be improperly mixed. MMA will also easily bond to previously cured MMA or epoxy. The vacuum installation of MMA can be used to repair the shallow crack fill depth often associated with pressurized epoxy repairs.

 

The basic monomer of the material is methyl methacrylate (MMA)...a slightly amber colored liquid that looks like colored water and is about the same viscosity. It has a sharp odor that can be detected by smell in as little as one part per million. The odor of the monomers, and toxicity commonly associated with all polymer components, requires the usual precautions for handling. Foremost with the use of MMA, is proper and adequate ventilation of the emitted vapors. During interior installations, our technicians employ high volume air moving exhaust equipment that totally exhausts the vapors from the work area to the outside. An inhibitor is added to the monomer for longer storage times. These inhibitors are special additives used in MMA to prevent premature polymerization that can be caused from excessive temperatures, contaminates, etc.. The two most common inhibitors are methyl ester of hydroquinone (MEHQ) and hydroquinone (HQ). These inhibitors are normally added to the monomer by the resin manufacturer and require no field mixing or attendance to whatsoever. Promoters are also added in very small quantities and are used to increase the decomposition rate of the initiator, which will result in faster curing of the polymer. The general preferred promoter used is dimethyl-para-toluidine (DPT), a liquid with the same viscosity of the MMA.

 

Just prior to application, the initiator is added to this mixture of MMA by our technicians; so begins the polymerization process, or curing of the repairing resin. Benzoyl Peroxide is the customery initiator and is a white powder or liquid that readily dissolves in the MMA. The amount of initiator added to the MMA is at the discretion of the technician and directly related to the time desired for curing the polymer. Increased amounts of initiator will result in more rapid polymerization of the monomers. 

 

Physical properties of the cured materials are comparable to epoxies and other high strength resins and generally range in the area of: 10,000 psi compressive strength, 7,000 psi tensile strength, 4,000 psi flexural strength and 700,000 psi modulus of elasticity.

LEAK REPAIR MATERIAL

Expanding Vinyl Ester

 

This is a 3 part, low viscosity, water-soluble acrylic resin used for the injection and sealing of joints and cracks against water leaks.

 

Due to its ultra low viscosity, this material has a very low flow resistance and is therefore able to permeate into the smallest of hairline cracks and capillaries, sealing the leak repairs reliably and permanently the first time; with set times as short as 30 seconds.

 

Because the polymerized material will swell to double its volume, dimensional changes will not affect the seal as it does with conventional expanding urethanes. The resins are solvent free and during the hardening (polymerization) stage, the monomers link together to form long chains. These chains are themselves cross-linked to form a three dimensional network, or a single giant molecule. There are, however, small side-chains combined with the molecule which have a water-soluble character. Unlike conventional expanding polyurethanes typically used for leak repairs, when these side-chains come into contact with water, the side chains de-stabilize in the water; but because of its size, the whole molecule does not. Instead, the perimeter of the material will take up the water and swell while retaining its external shape. Like the solution of common salt in water, the process is purely physical and is therefore reversible. Because of this unique property, and again, unlike conventional expanding polyurethanes, this material will retain its self-healing properties even when in a dry condition.

 

The swelling and re-swelling is strictly dependent upon the availability of water. After a period of dryness, a re-wetting or dampening environment will re-hydrate the material and will again transform it into a state of equilibrium, or swelling gel. Just the mere moisture within a concrete matrix will keep the material in a swelled state.

 

This vinyl ester repair resin, coupled with Tecvac's TecSealtm Leak Repair Process, contributes substantially to the success of our repairs and has a number of advantages over polyurethanes typically used for this sort of work: Low viscosity (1cps) and low flow resistance, vinyl ester penetrates into the narrowest cracks and capillaries. Because the resin does not chemically react with water, there is no foam layer or resulting reduction of adhesion that accompanies polyurethanes. But most importantly, is the ability of the vinyl ester to self-heal after dry periods. Unlike polyurethanes, the cured gel experiences little shrinkage when dried and will re-swell when contacted with water and will reestablish equilibrium. This material provides an unparalleled reliability and a dependably lasting repair.

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