P+M POLIMER KÉMIA KFT.
Az epoxi  specialista! (R)
hungarianromana
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The most frequently asked practical and technological questions regarding the application of our products are collected among the Frequently Asked Questions. In case You do not find the answer for your question in our homepage, please contact our representative.

Tel.: +3614217040
Fax.: +3614217041
H-1238 Budapest, Helsinki út 114.
info@pmpolimer.hu

Questions

1.

How should the resin and hardener be mixed?

2.

How much material should be mixed at once?

3.

What can the resin mix be diluted with?

4.

How can cross-linking be accelerated?

5.

How does temperature influence processability time and system properties?

6.

What can the system be dyed with?

7.

What filling materials should be used for epoxy resins?

8.

What impact the filling material has on the properties of the resin mix and the end product?

9.

What can a mold be cleaned with and how long?

10.

What can reactive diluents be used for?

11.

What safety provisions have to be applied during usage?

12.

How can bubble formation be avoided?

13.

How long can the epoxy resins and cross-linking agents be stored?


Answers

1.

How should the resin and hardener be mixed?

 

Always keep accurately to the mix ratios specified for mass on the technical data sheets. If the cross-linking agent is overdosed that ruins the electrical and mechanical properties, and in extreme cases the product does not harden at all. Owing to the different densities of the components, mixing in volume ratio may result in the deterioration of the properties of the end-product, and in extreme cases the product does not harden at all.
The cross-linking agent should be flown on the side of the tank and added to the resin this way. The two materials should be mixed perfectly, preferably with a low rpm mixer mounted on an electric drilling machine, and the mixing head should always remain under the surface of the liquid so that no air is taken into the mixture. Mixing can be carried out in other ways, too e.g. with manual mixing, the important aspect is that the mixture should be completely homogeneous, and no bubbles should be taken into the material. The mixed material should be poured into another empty pot, and mixed again there.
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2.

How much material should be mixed at once?

 

Mix only an amount that can be utilized within the processability time.
The mixed resin and cross-linking agent starts to react immediately, and release heat meanwhile. In case of larger masses, this heat cannot leave, and that makes the reaction even faster, hence in case of mixing a larger amount, it is worth keeping it in a tank with a larger surface or cool the tank from outside Since reaction heat accelerates the reaction, the same material binds more quickly if the amount or the layer thickness is larger and all other conditions are the same.
The processing time of filled systems is longer than that of unfilled systems (of the same quantity).
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3.

What can the resin mix be diluted with?

 

No thinner should be added to the mixture. If the mixture does not seem to have the adequate viscosity for a given purpose, choose another system.
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4.

How can cross-linking be accelerated?

 

Bonding time can be decreased by heating at 40-60 °C. The chemical reaction accelerates owing to the heat, so adequate care should be taken!
Bonding time cannot be accelerated with a higher amount of cross-linking agent. In extreme cases the impact can be opposite, the system cannot cross-link, and remains 'sticky'.
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5.

How does temperature influence processability time and system properties?

 

Even temperature and low humidity are important for the production of high quality products. If it is possible, work with a resin kept at room temperature, since the viscosity of the too cold resin increases, hence the perfect homogenization with the cross-linking agent, good spreading and space filling are all more difficult.
+10 °C temperature increase  no processability time decreases to its half (compared to room temperature)
-10 °C temperature decrease no processability time doubles (compared to room temperature)
Do not use the product below the temperature given in the technical data sheet, since its surface may remain sticky and it does not bond completely
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6.

What can the system be dyed with?

 

The EPOREZIT two-component epoxy resins can be dyed with coloring pastes or powder pigments.
Never use water based coloring agents with these systems, since water inhibits cross-linking.
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7.

What filling materials should be used for epoxy resins?

 

Mineral fillers (dried sand, silica flour, talc, aerosil etc.) can have beneficial impact on both processing and the properties of the end product depending on the application
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8.

What impact the filling material has on the properties of the resin mix and the end product?

 

In case of applying filling materials, heating up decreases during cross-linking, the processability time of the mixed material increases, shrinkage decreases, the unit cost of same size pieces is lower. The compression strength, hardness, Martens heat resistance of the end product improves, and water absorption will also decrease. However, other mechanical properties deteriorate to a given extent, and the mixture of larger viscosity is difficult to exclude bubbles from and more difficult to process. The amount of added filling material is optional, can even be a multiple of the amount of resin
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9.

What can a mold be cleaned with and how long?

 

In case mixing is done in a polyethylene pot, the remaining material can be snapped out with a mechanical impact. Other pots, tools, brushes, rollers all have to be cleaned with an EPOREZIT tool cleaner or an organic solvent, such as acetone immediately after usage. In case of product EPOREZIT AKVA 100, the tools can be cleaned with water. If the resin is already bonded, the tools can no more be cleaned.
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10.

What can reactive diluents be used for?

 

The EPOREZIT reactive thinners are epoxy compounds that contain no additives and can be used for diluting and modifying epoxy resins.
They react with EPOREZIT cross-linking agents in the same way as epoxy resins do.
Their application field is mainly the modification of epoxy resins, as more diluted, less viscous resins can be produced using these thinners. Not only does the viscosity of the resins diluted with reactive thinner change but also their reactivity, hence in case of the reaction with the cross-linking agent the reactivity of the diluted resin and not the original resin should be considered.
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11.

What safety instructions have to be applied during usage?

 

The general chemical industrial safety instructions concerning epoxy resins and cross-linking agents have to be obeyed. The resins are maximum slightly irritant, while the cross linking agents are irritant and can cause skin problems on sensitive parts such as hand, arm and eyelid. The vapors of the cross-linking agents strongly irritate the eyes and mucous membranes, hence good ventilation has to be provided at the workplace. Take care that the material does not spatter in the eyes both in case of mixing and pouring..
It is compulsory to wear safety glasses and adequate safety gloves. If the material gets in contact with skin, it should be washed off with plenty of water. Skin must not be cleaned with a solvent, since the solvents can help the quick absorption of cross-linking agents.
If work is interrupted or finished, hands should be washed thoroughly and greasy protective hand creme should be applied. In case of contact with the eyes, the material should be washed with a plenty of water immediately, and rinse with a physiological salt solution. The general protective rules should be obeyed when processing epoxy resin products. Provide adequate ventilation.

The cross-linked system has no harmful impact on the environment or on health, as far as we know.
Detailed information can be found in the material safety data sheet.
If skin inflammation or eye injuries occur despite the above mentioned measures, medical help should be sought
Eating, drinking and smoking are prohibited during working!
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12.

How can bubble formation be avoided?

 

The resin and the cross-linking agent should be mixed with a low rpm mixer, and the mixing head should always remain under the surface of the liquid so that no air is taken into the mixture. Bubble formation can be minimized this way.
The resin is heated up to 80-90°C and you should wait until the bubbles leave. If a filling material is also used, first add the dry filling material to the resin and then exclude bubbles. The cross-linking agent should be mixed into the resin free from bubbles and cooled down to room temperature. The resin mixed with the cross-linking agent should not be heated again since the warmer system is firstly more flowable and less viscous but the reaction accelerates and processing time decreases suddenly.
Bubbles can be excluded by applying vacuum or de-aerating additives (for further information, please contact our representatives).
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13.

How long can the epoxy resins and cross-linking agents be stored?

 

Resins can be kept in dry places, in closed tanks, possibly in covered warehouse areas for several years. The cross-linking agents applied with them can be stored for 1 year. Some cross-linking agents are especially sensitive to the humidity in air, hence if only a little material is left in an opened pot, it is practical to put it into a smaller tank and close it properly. The material of the storing pot can be metal, plastic or glass.
At lower temperatures the cross-linking agents can crystallize, but if they are warmed (up to 50°C) a little before usage, this can be ceased (reversible process). Before usage, always wait until the product cools down to room temperature.
Both product components should be kept away from water, humidity and radiant heat.
Our guarantee on the products is valid for 1 year starting from the date of purchase.
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