Joining of glass

Joining by ultra-violet

DATA SHEET JOINING BY ULTRA-VIOLET -->

History

It is in 1985, that the first adhesives with Ultraviolet made their appearance on the market. They are used for joinings of the Verre with various materials (Fer, metal, Bois, plastic S…). In addition to these applications, they are also employed in glass of decoration, glass Optique and electronic glass . They bring today much of advantages to certain technologies of production. The uses are very broad thanks to the excellent characteristics of the adhesives. Everywhere where a high adhesion and a transparent optical joining are necessary, adhesives UV are a good solution.

Definition

; Stick: sticky matter spread out on the surface of an object to make it adhere to another ( Petit Larousse 1980)

The joining of glass

According to the project to be realized, one uses the adhesive best adapted (adhesive silicone, Araldite adhesive with hardener, adhesive neutral mirror, two-sided adhesive tape…).

Adhesive UV is an adhesive which polymerizes under the action of the ultra-violet. The success of adhesive UV is particularly due to easy employment, a polymerization controlled by irradiation of lamps UV, strong adhesions also at high temperature as well as the optical transparency of joining. One obtains solid and durable joinings between glass like with other materials.

Conservation

To preserve adhesive UV at the expenses, dryness, the darkness (without radiation UV). In closed packing and of origin, the shelf life is twelve months. Before employment, to bring the adhesive up to a room temperature. During a light warming (between 30 and 40 °C), the adhesive is liquefied and made it possible possible bubbles of air to escape.

Notice

For constructions where the assemblies must remain elastic or are continuously exposed to water, for example the aquariums, adhesives UV are not adapted.

Polymerization

In practice, polymerization occurs by the use of a lamp UV adapted. The duration of hardening depends on the following factors: spectrum and power of the lamp, outdistance between the lamp and the adhesive, seniority of the lamp, thickness of the adhesive applied, effect of surrounding materials (example: transmission, absorption, reflection).

According to these factors, the duration of hardening lies between 15 seconds and 5 minutes; under bad conditions, this time can lengthen. A preventive test is desirable to know the exact time of irradiation. A longer duration is not a disadvantage. The dangers of yellowing, burn, tensions of materials are practically excluded.

Application

Surfaces to be pasted must be dry, of dust, grease and separating agent. An easy finish of cleaning with White spirit, methylated spirits, eliminates remaining moisture thanks to its hygroscopic effect. The normal roughness of surfaces is in general sufficient to obtain good joinings. The application of the adhesive on surface to be stuck must be done without bubble, economically but sufficiently using the dosing end of origin. It is important that the elements are assembled without tension. After the assembly, one operates a fast polymerization with a manual lamp with ultra-violet. Note: adhesives UV absorb rays UV. This is why polymerization is only possible in low thicknesses. To position the lamp more close possible joining to decrease the loss of radiation. During complicated joinings, one can radiate using mirrors or with blank paper.

Cleaning

Before hardening, the adhesive can be easily removed with one cleaning or a rag. After joining with UV, i.e. after complete hardening of the adhesive, to clean the surpluses with a padded stick or a rag soaked with alcohol or Solvent, by rubbing the resin hardened until the disappearance of this one. If this operation is not sufficient, to use a razor blade to scrape the adhesive, by paying attention not to stripe glass.

Tools

To practice ultraviolet joining, it is necessary obligatorily:

a lamp UV;
a product of cleaning to remove dust and greases;
an adhesive specific for the joining of glass to glass, glass metals, plastic glass…
a pair of glasses of protection;
a razor blade, to scrape the dried adhesive which can overflow of the perimeter of joining.

Others

Disassembling

A possible disassembling of the stuck parts is possible neither mechanically nor chemically. It is possible to operate a disassembling at a temperature of 200 °C if the materials allow it. There exists a risk of break during irregular warming and of cooling of glass. For the small parts, an separation could be done in a vat with water during several days.

The Councils

A novel method must always be tested before. During joining of large surfaces, it can create tensions as well as bubbles. To avoid that, would be needed a gradual polymerization:

To apply the adhesive without formation of bubbles.
Assembly of the parts without tension.
To radiate the central part during 2 or 3 minutes.
To widen surface to be radiated with 2 cm, and to radiate again.
So on until totality.

In this way, the adhesive equalizes the tension. It should be made sure that there is enough adhesive on the circumference. Before the last operation of polymerization, one can wipe the adhesive, which will avoid a hard cleaning. The use of materials with a thermal dilation coefficient different does not pose a problem at the time of small elements. On the other hand, at the time big lengths, there can be breaks of glass during temperature variation.

Safety

As for other chemicals, it is imperative to follow certain safety regulations during the use of the products and lamp UV. It is necessary to respect:

a good ventilation of the buildings.
To avoid any contact of the adhesive with the eyes, the skin, the mucous membranes.
To carry safety goggles as well as gloves.
not to eat, drink nor to smoke during work.
At the time of contact with the eyes or the skin, to rinse abundantly with water and soap.

Other adhesives for glass

The adhesives silicone (standard RTV for example), the adhesive Araldite with two components, adhesives for mirror (neutral for silvering), the two-sided adhesive, the cyanoacrylate (super glue) Loctite.

Material and materials

ultraviolet Lamp 400 Watts
liquid or thick Adhesive UV out of bottle
Solvent cleaning

Characteristics

Strength to the temperature - 40 °C with + 150 °C with chemical substances. The photo initiators included in the adhesive react to certain wavelengths of spectrum UVA what causes polymerization.

Application: directly bottle on glass (thickness of ideal adhesive: 0,5 mm). Surfaces to be pasted must be dry and perfectly degreased.

Hardening: it is carried out under the influence of rays UV between 10 and 120 seconds according to the thickness of adhesive and the nature of glass. After the operation, the superfluous adhesive can be removed with solvent.

Precaution: although not very toxic, the adhesive can cause allergies, at the time of prolonged contacts. To wash itself with water and the soap.

Method

To envisage a white sheet under joining to be realized, to return the luminous rays in glass. To heat the adhesive for a better displacement of the liquid.

To degrease the parts of glass to be stuck with solvent.
to paste only one of surface with adhesive UV.
To place the two parts in contact and to support gently.
To drive out the bubbles of air (possibly wedged between glasses).
To position and fix the unit.
To insolate under lamp UV during 2 or 3 minutes.
To clean before the total polymerization of the adhesive.

Caution

Not to expose the eyes to rays UV, to place themselves behind the lamp during the insolation of glasses.

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