Below you will find some basic information in order to gain a rough overview of our products. Please do not hesitate to contact us, if you wish to select concrete products. Our experts will help you to make the right decision.
Since 2004, HA CZ has been producing furan resins called Kaltharz. We offer a wide variety of resins produced according to our own proven recipes.
Together with the activators produced by our affiliated company Habrinol, these resins allow – in the process of producing molding sands – to cover a broad range of needs of foundries regarding the production assortment of castings or the nature of manufacture of forms and cores, i.e. from temperature conditions of the production involving both hot summer and harsh winter up to various technological aspects of foundry production.
We offer Kaltharz resins for standard and quick curing of the molding sands using different types of base sands (high-silica sands, chromite sands, etc.) for both grey and nodular graphite iron, and for steel we offer resins with nitrogen content of 1 % and less. There is also a full range of proven modifications: some for grey and nodular graphite iron with reduced, but not completely low nitrogen and water content as for steel as well as variants with an optimized price level.
Owing to their high quality, our standard resins allow low additions and are characterized by good strength, low development of gas and odour and good flowability of the molding sand and thus also optimum homogenisation of molding sand components due to low viscosity of these products.
By choosing the suitable quantity and type of activators used, resins can be very well adjusted, in order to easily optimize their reactivity and thus also the subsequent speed of curing of the manufactured molding sand with respect to the type of foundry sand used and the curing conditions given especially by the temperature of this system as well as of the environment.
At the moment, this activity is often performed automatically when preparing molding sands, i.e. by dosing the appropriate quantity and type of activator with respect to immediate temperature of the base sand and environment. An example may be the AUTOFEEDER which we constructed in cooperation with Elkoso.
For special purposes, we furthermore offer the following systems from our production:
- Low-sulphur systems by using reactive resins and corresponding slow activators containing lactic acid, which reduce the amount of sulphur in reclaim. In this way we are able to prevent graphite degeneration in parts close to the surface in nodular iron castings as well as strong odour during casting caused by SO2 emissions in reclaim. Problems with the odour may also be caused by outdoor storing of the reclaim, particularly in summer. That is why these systems are being applied in many cases despite their higher price.
- Kaltharz products with faster, but due to additives used, still plastic curing process, which are well suitable for steel castings due to their nitrogen content amounting to 0.5% and less.
- nitrogen-free Kaltharz products.
Due to the enormous price increase of furfuryl alcohol (FA), the main raw material for manufacture of furan resins, we have alternatively developed a whole range of new Kaltharz products, for which we have been gradually substituting FA by other components while maintaining our existing recipes. This process allows the customers to test, without a risk, several variants under their own conditions and to decide, which rate of substitution of furfuryl alcohol suits them best.
These are primarily our Kaltharz products of the TF range, where FA has been substituted by a high-quality phenolic resin. Where it is not desirable to use phenol, e.g. due to waste disposal, we offer the phenolic free products within the TP range.
Pure phenolic resins from the holding’s production are also available.
Unfortunately, this step in developing new types for furan-phenol-formaldehyde binders is inevitable in the sense of constantly increasing prices of FA, as mentioned above. However, we are still encountering the deep-routed mechanisms of individual foundries that are afraid to undergo practical tests of these new binders under the supervision of HA CZ, but they would like to buy existing binders at the much lower old prices. This situation is very critical and leads us constantly to a certain type of persuasion... however, here in the Czech Republic as well as in the neighbouring countries there are already many practical examples of series production, which is fully functional. This is all a compromise in long-standing habits where price of the final product plays the main role. The HA CZ solution rests upon different content of the phenolic resin in the final product. All our suggestions on the applicability of these furan-phenol-formaldehyde binders are based on practical discussions with foundries where we rely on the existing state of functionality. It has to be said that by using the furan-phenol formaldehyde system, we do not only bring a solution in the form of a price alternative, but also this technology is an adequate solution for applicability in foundries.
Suitable activators can control the system of molding mixture lifetime, mold curing and stripping of the model equipment. The environment, temperature of the environment as well as temperature of the sands also play a role, so in terms of usability we look at this system with the same eyes as at the classic furan system. Kaltharz products with a 30% substitution of FA are already being used in series; other products with up to a 50% substitution are being tested.
Examples for usage of furan-phenol resins:
Substitution of 38% FA
- Substitution for the classic furan resin containing 90% FA.
- Large foundry of nodular and gray cast iron, piece to small-lot production, castings from 0.5 kg to 25,000 kg.
- Dosing for smaller castings up to 3 tons: 0.9% resin + 0.3% curing agent; also used for largest castings.
- Molding mixture lifetime 5 to 10 minutes – depending on the conditions – sand and hall temperature.
- Time to dismantle molds approx. 30 min – also depending on the conditions.
- Strengths after 24 h approx. 180 N/cm2.
The application of this resin with a high proportion of the phenolic component allows in particular stable molding conditions at this foundry – the temperature of the hall in the winter period approx. 20 °C, sand temperature from 20 to 30 °C and usage of more reactive curing agents. In the case of cooler conditions, slower reactivity is to be expected and it is therefore necessary to consider where this resin can be used. In view of the results achieved, the resin meets all the essential requirements.
Substitution of 25% FA
- Substitution for the classic furan resin containing 77% FA.
- Medium-sized cast iron foundry, piece to small-lot production, castings from 5 to 12,000 kg.
- Dosing 0.85% resin + 0.3% curing agent.
- Molding mixture lifetime approx. 10 min – depending on the conditions – sand and hall temperature.
- Time to dismantle molds approx. 30-40 min – also depending on the conditions.
- Strengths after 24 h approx. 140 N/cm2.
The resin meets all production requirements, with no significant changes occurring during the transition. Resin has good functionality even under conditions where the hall temperature drops below 10 °C, of course depending on the sand temperature which significantly affects the speed of curing.
Substitution of 15% FA
- Substitution for a classical furan resin containing 84% FA.
- Large foundry of cast iron and steel, piece production, castings from 1,500 to 300,000 kg.
- Dosing of 1.15% of resin + 0.5% of curing agent.
- Time to dismantle molds approx. 8 -10 h – depending on surrounding conditions.
- Strengths after 24 h approx. 180 N/cm2.
The resin achieves good results in the production, and the dosing proportion could be even slightly lower. However, due to fluctuating temperatures in the foundry, the reserve in dosing is legitimate. The resin has proven itself and today it is part of standard product deliveries.
Products from the programme of HA holding
We offer all HA products such as Cold Box, Hot- and Warm-Box, Carbophen (Resole/CO2), refractory coatings, coating resins and resin-coated sands, parting and release agents for pressure casting, bentonite, compounds of bentonite and lustrous carbon and much more. For more information please visit www.huettenes-albertus.com.
This link applies to the inorganic adhesives as well. Although we have been producing the adhesives on our own, the holding is responsible for the development and their distribution outside the Czech and Slovak Republic. Recent information on these products can be therefore found on the web page given above.