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| News 20.06.2008Ecological polyols for 2K-PUR applications With the products Rokrapol VP 5035, VP 5158, VP 5161 and VP 5162 Robert Kraemer provides ecological polyols which show in spite of the OH-functionality a high aliphatic tolerance. Thereby the adhesion properties on fatty and oily substrates will be increased. Because of the ecological modification the wetting properties will be improved in order to obtain higher pigment or filling rates. The high resistance of the resins results no changes in hardness, adhesion and flexibility of the film on water strain in long-term stress-test. The chemical resistance against sulphuric acid and alkaline media is given, too. Stress-tests with sundry solvents like MEK cause any damages on the film. The used content of renewable raw materials for the new polyols is between 92 and 100 %. 30.04.2008
Especially for offset printing inks, Robert Kraemer offers now, besides the well-known standard resins as phenolic modified rosin esters and long oil alkyd resins, two new special resins which as combination partners help to adjust important printing parameters. Rokralux VP 4641 is a modified soyabean oil alkyd resins with a medium oil length which is highly polar. However, it still has a very high mineral oil tolerance. By its comparably shorter oil length, this resin distinguishes itself by a fast drying process, high gloss and a good abrasion resistance. Especially, the possibility to create a "positive" (hydrohpylic) water balance is remarkable. Contrary to this, Kramorex VP 4048 from our range of modified urethane resins can create a "negative" water balance according to its very low polarity and therewith strong hydrophobicity. Furthermore, this mineral oil solved urethane resin shows very good adhesion and wetting properties. Therefore, it is possible to use this adhesion promoting resin in printing inks also on strongly coated papers or foils. 30.04.2008
According to the strong demand for ecological resins, especially for water based applications, Robert Kraemer has extended its production range, especially by new emulsifiable resins. Therefore, with Rokralux LE 158 W a linseed oil based alternative and with Rokralux SBE 158 W a sunflower oil based alternative are available. These resins can be easily emulsified into the water phase and they are giving stable emulsions. A special guidance formulation describing this can be obtained on request. Both resins complete our well-used standard type for solvent respectivley 100% solid applications, as the linseed oil based resins Rokralux LE 156, Rokralux LE 160 as well as the soyabean oil based resin Rokralux SE 160. Compared to classical oil boiling systems (stand oil/resins), all listed resins distinguish themselves besides by shorter drying times and higher hardness by a better weather and yellowing resistance. 30.04.2008
Already for some time Robert Kraemer is offering several combination resins to solve adhesion and wetting problems in UV systems. According to this, Rokracure 6000 as 75% solution in HDDA has quite fast found a good feedback in the market as adhesion promotion resin, especially because with this resin the use of cost intensive, acid adhesion promoting additive resins can be reduced or even completely avoided. Having similar properties, the further development Rokracure VP 4864 shows a higher polarity. With this, special demands regarding improved adhesion and wetting properties can be fulfilled. As a current further new development Rokracure VP 4631 is available which distinguishes itself besides by very good adhesion values by a strong flexibilization and plasticizing effect. Additionally, especially in reactive systems, with this resin the strong shrinkage behaviour of high functional reactive diluents and binders can be compensated. 30.04.2008
As leading producer of resins for flexographic printing inks, the company Robert Kraemer has extended its production programme by some new maleic resins: Erkamar VP 4223 is a strongly hydroxyl functionalized maleic resin with an extreme low acid value. Its use in alcohol soluble flexo and packaging gravure printing inks improves the adhesion on plastic substrates, especially on poly-olefins and polyesters. Additionally, the use with metallic pigments shows very good stability properties. Based on its hydroxyl functionality, this resin can also be used for crosslinked systems. Erkamar VP 4760 has been developed as an excellent water soluble maleic resin. It distinguishes itself by especially a very high gloss value and universal adhesion properties. The neutralisation of this resin is possible with ammonia as well as with amines. Therefore, Erkamar VP 4760 is especially suitable as gloss improvement resin for aqueous lacquers and printing inks. 30.04.2008
With the exclusive special KRAMOREX range developed by Robert Kraemer, now for the user several new additive resins are available to solve adhesion and wetting problems in various applications: 30.04.2008
Besides the solution of the "VOC problem", the producers of adhesives now are also looking with an increasing tendency into the sustainability. This fact has caused the company Robert Kraemer to develop viscous soft resins which are only based on ecological raw materials and which are especially not based on the crude oil substitute ethylene glycol. According to this, Robert Kraemer is offering with Bremasin 1900, 1902, 1905 and 1908 new soft resins as tackifiers which do not contain any crude oil based raw materials and which consist 100% of sustainable raw materials. These new soft resins are available in a broad viscosity range from 1000 mPas at 20°C to 100.000 mPas at 40°C. They are successfully used as tackifiers in various adhesives as well as combination resins for adjustment of the melting viscosity of solid resins. Furthermore they distinguish themselves besides by good compatibility and adhesion properties also by a good wetting of fillers and a higher water resistance which is obtained by their special new structure. Another advantage of the new soft resins is achieved in water based flooring adhesives where for the production besides dispersions still today high boiling solvents respectively plasticizers as solution and transportation aid for solid resins are needed. As these unwanted substances e.g. adipates, citrates, dibenzoates and styrolized phenol have to be named. These crude oil based, plasticizing substances can be completely replaced by our new ecological soft resins with low viscosity and act in this usage not only as solvent or plasticizer but improve additionally the bonding strength of the adhesive. This allows the formulation of flooring adhesives with considerably lower VOC values which additionally have a much larger sustainability. Especially useful for this purpose is the extremely low viscous type Bremasin 1900. With Bremasin VP 3112 now a further development with higher polarity and therewith also higher hydrophilicity is available which is resulting in a better emulsification behaviour and higher storage stability, especially in highly filled formulations. The higher viscous alternatives Bremasin 1905 and Bremasin 1908 are used besides the low viscous solution resins for adjustment of the tack. In order to achieve also for highly filled systems good wetting and adhesion properties combined with a high storage stability, with Bremasin VP 3288 a more polar alternative with additional hydroxyl groups is available in the high viscosity range. Usually in water based flooring adhesives, besides soft resins also hard resins are used to adjust the adhesive properties. In order to spare the adhesive producers a technical complicated processing of solid resins, based on the before described new soft resins, Bremar VP 4834, a viscous, well used rosin ester compound is offered, which is completely based on natural sustainable raw materials, doesn't contain any plasticizers and is also giving a low VOC value. Especially this type has proven itself having very good adhesion and emulsification properties. Furthermore, it is also possible to require tailor-made compounds based on the new soft resins. |
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