Use of an epoxy resin-based binder system

Abstract

Use of an epoxy resin-based binder system as a thermoplastic material for surface layers, namely for coating drivable asphalt surfaces, characterized in that the binder system is made from a mixture of 40 wt.% - 60 wt.% of a resin component A, 15 wt.% - 40 wt.% of a hardener component B and 15 wt.% to 35 wt.% of a vegetable oil according to a component C, which replaces proportions of the resin component A in the mixture.

Description

[0001] The present invention relates to the use of an epoxy resin-based binder system as a thermoplastic material for surface layers, namely for coating drivable asphalt surfaces.

[0002] Epoxy resins are usually two-component materials that harden into a thermosetting plastic through an exothermic reaction (especially polyaddition). A distinction is made between "warm" and "cold" curing systems, with the invention preferably being used in cold-curing systems.

[0003] Epoxy resins are synthetic resins containing epoxy groups. They are thermosetting resins (reactive resins) that can be reacted with a hardener and, if necessary, additives to form a thermosetting plastic. Epoxy resins are polyethers with typically two terminal epoxy groups. The hardening agents are reactants and form the macromolecular plastic with the resin.

[0004] Thermosets produced through crosslinking possess good mechanical properties as well as good temperature and chemical resistance. They are therefore considered high-quality, but also expensive, plastics. They are used, among other things, as reaction and stoving enamels, adhesives, for laminates, as embedding materials in metallography, and as molding compounds for components in electrical engineering and electronics.

[0005] Thermosets, also called thermoses, are plastics that cannot be deformed after they have hardened. Thermosets are hard, glass-like polymer materials that are three-dimensionally cross-linked via chemical main valence bonds. The cross-linking occurs when mixing precursors with branching points and is activated either chemically at room temperature with the help of catalysts or thermally at high temperatures.

[0006] German patent DE 296 23 574 U1 discloses a resin / filler system for producing coatings and for manufacturing plastic floors with a natural stone effect. These floors are intended as a cost-effective alternative to expensive natural stone floors such as granite and are therefore designed for interior use in buildings. For the reasons mentioned, the decorative effect is paramount in these plastic floors. The resin composition consists of a two-component epoxy resin, which may contain silicon dioxide or quartz powder as fillers. A cycloaliphatic amine can be used as the hardener component. The examples given describe resin compositions containing a bisphenol A / F epoxy resin and a cycloaliphatic amine in a weight ratio of approximately 2:1, as well as basalt, marble, or granite chippings as a mineral filler in a weight ratio of filler to bisphenol A / F epoxy resin of approximately 5.5:1.The weight ratio of hardener component to bisphenol resin component is therefore comparatively high, and the proportion of the two synthetic resin components in the mixture with the fillers is approximately 15%.

[0007] German patent DE 69506216 T3 describes two-component reactive resins consisting of a bisphenol-A resin and a cycloaliphatic polyamine as the hardener component, which may contain silicon dioxide powder as a filler. These two-component reactive resins are used for the production of tile flooring and are therefore also intended for interior flooring applications in buildings. These tile floors are designed to be resistant to a wide variety of chemicals, including acids and bases, as well as alcohols and hydrocarbons.However, this publication does not specify the exact composition of the two-component reactive resins, nor does it contain specific details of investigations into the resistance of the tiles to hydrocarbons, so that the publication does not provide the person skilled in the art with any concrete instruction as to which components are to be mixed in what proportions in order to obtain a reactive resin mortar which, after hardening, exhibits a special degree of resistance to hydrocarbons and related liquids and which is also suitable for particularly stressed, especially trafficable, surfaces that are exposed to the elements outdoors.

[0008] Binder systems containing epoxy resin, vegetable oil or castor oil, and an amine-based hardener are known from DE 12 26 451 A in the prior art. Polyamines and polyamidoamine, among others, are disclosed as hardeners in EP 2 638 092 B1. The two aforementioned documents, as well as WO 2014 / 174 033 A2 and JP.20004359746 A, disclose both reactive incorporation of the vegetable oil and non-reactive admixture.

[0009] The object of the present invention is to provide a binder system of the aforementioned type which is modified in such a way as to make it possible to impart at least partially thermoplastic properties to a composition according to an originally thermosetting epoxy resin.

[0010] The solution to this problem is provided by the use of a binder system of the aforementioned type with the characteristic features of the main claim.

[0011] According to the invention, the aforementioned vegetable oil serves to modify an epoxy resin composition by replacing a portion of the resin component with a vegetable oil, which is either reactively incorporated into the curing process or remains in the mixture as a non-reactive component, thereby imparting thermoplastic properties to the otherwise thermosetting epoxy resin. This modification thus creates a thermoplastic material that can be deformed within a specific temperature range. This process is reversible in thermoplastics, meaning that it can, in principle, be repeated any number of times by cooling and reheating the material to a malleable state, as long as overheating does not cause the so-called thermal decomposition of the material. This is what distinguishes thermoplastics from thermosets and elastomers.

[0012] The invention modifies the properties of the thermosetting epoxy resin by adding vegetable oil, giving it thermoplastic properties while maintaining nearly constant compressive and flexural strengths. This mixture can be used, for example, as a binder for a surface coating on asphalt with high wear resistance.

[0013] Thermoplastic behavior is advantageous, for example, in surface coatings on other thermoplastic materials. This application is particularly important in road construction, where asphalt is a thermoplastic building material.

[0014] Existing coatings on asphalt, due to their thermoplastic properties, have lower abrasion resistance and a correspondingly short lifespan under traffic loads. A thermoset would be well-suited in principle, as it exhibits higher strength. However, the use of a thermoset on asphalt is not possible because the asphalt, during temperature-related softening or hardening, would develop stresses against the differently behaving thermoset. This would lead to delamination of the coating. This problem has previously been addressed by adding flexibilizing additives. However, this flexibilization in a thermoset is permanent and not temperature-dependent, which, while resulting in more favorable stress behavior with respect to the substrate, impairs the load-bearing capacity, particularly the abrasion resistance.

[0015] According to a preferred embodiment of the invention, the resin component A comprises at least one bisphenol-based epoxy resin and / or the hardener component B comprises at least one amine-based hardener.

[0016] Furthermore, according to a preferred embodiment of the invention, the vegetable oil according to component C is preferably a castor oil. Such a castor oil contains a relatively large proportion of triricinolein (tri-ricinoleic acid glycerol ester) and allows the production of a wide variety of different compounds through numerous chemical reactions. Reactions take place at different positions of the ricinoleic acid ester (side chain of triricinolein).

[0017] This involves reacting at the cis double bond between C9 and C10, for example by means of oxidation, polymerization, addition, epoxidation or hydrogenation.

[0018] The aforementioned properties of castor oil and other similarly composed plant oils are already utilized in other technical products. However, in these applications, the plant oil functions either as a natural polyol in reaction with an isocyanate (for example, in polyurethanes) or as a plasticizer in other plastics such as PVC. A combination with a two-component epoxy resin, on the other hand, is not known from the prior art. Both undiluted and reactively diluted epoxy resins are used. These are typically cured with polyamine 15, but hardeners based on an adduct, Mannich base, or polyamidoamine can also be used.

[0019] Further developments of the invention provide that the vegetable oil is either reactively incorporated or remains in the system as a non-reactive component. It is also possible that the vegetable oil is embedded non-reactively in the system and protected from hydrolysis by the surrounding molecules of the epoxy resin / hardener matrix. Similarly, according to the invention, the vegetable oil is embedded non-reactively in the system and, due to its molecular size, remains in the system as a non-volatile component.

[0020] Furthermore, according to a further development of the invention, up to 40% of the resin component A is preferably replaced by the vegetable oil component C. When calculating the reaction, preferably only the proportion of epoxy resin is considered for determining the hardener addition. Due to the substitution of a considerable resin component, the hazardous substance content in the overall system is significantly reduced, leading to an improvement with regard to hazardous substance regulations. Furthermore, the price of the vegetable oil is, for example, only about 50% of that of the resin, making the system very economical.

[0021] Furthermore, according to a further development of the invention, the hardener component B may preferably comprise a polyamine, an adduct, a Mannich base or a polyamidoamine.

[0022] Furthermore, according to a preferred embodiment of the invention, the epoxy resin is an undiluted or a reactively diluted epoxy resin.

[0023] According to the invention, the binder system according to the invention is produced from a mixture of approximately 40 wt. % - approximately 60 wt. % of resin component A, approximately 15 wt. % - approximately 40 wt. % of hardener components B and approximately 15 wt. % to approximately 35 wt. % of vegetable oil according to component C, preferably from a mixture of approximately 45 wt. % - approximately 55 wt. % of resin component A, approximately 20 wt. % - approximately 30 wt. % of hardener component B and approximately 15 wt. % to approximately 25 wt. % of vegetable oil according to component C.

[0024] For example, the use of the binder according to the invention as a thermoplastic material for surface layers for coating drivable traffic surfaces is conceivable, in particular its use for coating asphalt surfaces.

[0025] The features mentioned in the dependent claims relate to preferred embodiments of the solution to the problem according to the invention. Further advantages of the invention will become apparent from the following detailed description.

[0026] The present invention will now be explained in more detail using an example. Example 1

[0027] An exemplary binder composition according to the present invention was produced by proceeding as follows: A mixture of three components was produced, namely 52.6 wt.% reactively diluted low-viscosity bisphenol-based epoxy resin with an epoxy equivalent weight between 175 and 230 g / mol as the first component A, 26.3 wt.% of a polyamine-based hardener as the second component B, which had an H-active equivalent weight between 73 and 114 g / mol, and 21.1% of a castor oil FSG as the third component C.

[0028] This mixture was cured for 168 hours under standard climate conditions (23°C, 50% RH) until complete crosslinking was achieved. A workpiece in the form of a disc with a diameter of 100 mm and a thickness of 8 mm was then fabricated from this material. The resulting workpiece exhibited low deformability at room temperature and was nearly rigid when stored at 10°C. Heating to 25°C increased its flexibility, allowing it to be manually deformed. At 35°C, it was flexible enough to allow deformation by 180° around its geometric axis. After cooling, these cycles were repeated several times, demonstrating a reversible thermoplastic property.

[0029] A coating made of the material produced according to the above specification was applied to a test surface of asphalt and this coating was subsequently subjected to several freeze-thaw cycles without any delamination or blistering.

[0030] The modified epoxy resin system according to the present invention is ideally suited for use on traffic surfaces, as it exhibits its special properties precisely within the required temperature range of approximately -15 °C to approximately +60 °C. Asphalt has a similar temperature behavior. Therefore, no stresses occur between an asphalt substrate and a coating produced on this substrate using the epoxy resin-based binder system according to the invention.

[0031] The modified epoxy resin can also be used, for example, as a binder for thermoplastic repair mortars. Such mortars are used, for example, in the partial repair of traffic surfaces and are significantly superior to the repair mortars or cold asphalt used so far in terms of durability.

Claims

[1] Use of an epoxy resin-based binder system as a thermoplastic material for surface layers, namely for coating drivable asphalt surfaces, characterized by , that the binder system is made from a mixture of 40 wt.% - 60 wt.% of a resin component A, 15 wt.% - 40 wt.% of a hardener component B and 15 wt.% to 35 wt.% of a vegetable oil according to a component C, which replaces proportions of the resin component A in the mixture. [2] Use of a binder system according to claim 1, characterized by , that the binder is made from a mixture of 45 wt.% - 55 wt.% of resin component A, 20 wt.% - 30 wt.% of hardener component B and 15 wt.% to 25 wt.% of vegetable oil according to component C, which replaces proportions of resin component A in the mixture. [3] Use of a binder system according to claim 1 or 2, characterized bythat the resin component A comprises at least one bisphenol-based epoxy resin and / or the hardener component B comprises at least one amine-based hardener. [4] Use of a binder system according to any of the preceding claims, characterized by that the vegetable oil according to component C is a castor oil. [5] Use of a binder system according to any one of the preceding claims, characterized by that up to 40% of the resin component A is replaced by the vegetable oil according to component C. [6] Use of a binder system according to any of the preceding claims, characterized by that the binder has thermoplastic properties. [7] Use of a binder system according to any of the preceding claims, characterized by that the hardener component B comprises a polyamine. [8] Use of a binder system according to any one of the preceding claims 4 to 7, characterized bythat the vegetable oil according to component C is a castor oil of quality FSG (first special grade). [9] Use of a binder system according to one of the preceding claims, characterized in that the vegetable oil is incorporated reactively or remains in the system as a non-reactive component. [10] Use of a binder system according to one of the preceding claims, characterized in that the vegetable oil is non-reactively embedded in the system and is protected from hydrolysis by the surrounding molecules of the epoxy resin / hardener matrix. [11] Use of a binder system according to any one of claims 1 to 8, characterized in that the vegetable oil is embedded in the system in a non-reactive manner and remains in the system as a non-volatile component due to the molecular size. [12] Use of a binder system according to any of the preceding claims, characterized bythat the vegetable oil contains a high proportion of tri-ricinoleic acid glycerol esters according to component C. [13] Use of a binder system according to any of the preceding claims, characterized by that the epoxy resin is an undiluted or reactively diluted epoxy resin. [14] Use of a binder system according to any of the preceding claims, characterized by that the hardener component B is an adduct, a Mannich base, or a polyamidoamine.