DE10306939A1 - Plastic composition containing unencapsulated phase-change material, e.g. dialkylammonium salt, used for temperature-equalisation, thermal conduction or heat storage, e.g. in varnish or ink for printing textiles or wallpaper - Google Patents

Abstract

Plastic compositions containing unencapsulated phase-change materials (PCM) and optionally also solvents, stabilisers and/or other auxiliary materials and additives.

Description

The present invention relates to the use of phase change materials in polymers.

In technical processes, often heat peaks or deficits are avoided, i.e. it must be thermostatted.

Usually is thermostatted with storage media that have a good heat capacity.

Known storage media are e.g. Water or stones / concrete around tangible ("sensitive") to store heat or phase change materials (PCM) such as Salts, salt hydrates or their mixtures or organic compounds (e.g. paraffin) for warmth in the form of heat of fusion ("latent" heat) too to save.

It is known that when melting a substance, i.e. at the transition from solid to liquid Phase, heat used up, i.e. which is recorded as long as the liquid state remains, is stored latently, and that this is latent Warmth at Freeze, i.e. at the transition from the liquid in the solid phase, is released again.

Basically is for loading a heat accumulator a higher one Temperature required than can be obtained during unloading for this the transport / flow of heat a temperature difference is required. The quality of the heat is the temperature at which it is available again, dependent: The higher the phase change temperature is, the better the heat can be dissipated. For this reason, it is desirable that the temperature level drops as little as possible during storage.

With sensitive heat storage (e.g. through Heating water) is a constant heating with the entry of heat of storage material (and vice versa when unloading), while latent heat the melting temperature of the PCM is stored and discharged. deferred heat storage therefore has opposite sensitive heat storage the advantage that the temperature loss affects the loss when heat transport limited to and from storage.

So far, as a storage medium usually in latent heat storage Substances used in the for the application of the essential temperature range a solid-liquid phase transition have, i.e. Substances that melt when used.

The use of paraffins as a storage medium in latent heat stores is known from the literature. The international patent application WO 93115625 describes shoe soles in which PCM-containing microcapsules are contained. Either paraffins or crystalline 2,2, -dimethyl-1,3-propanediol or 2-hydroxymethyl-2-methyl-1,3-propanediol are proposed as PCM. The application WO 93/24241 describes fabrics which are coated with a coating which contains such microcapsules and binders. Paraffinic hydrocarbons with 13 to 28 carbon atoms are preferably used here. In the European patent EP-B-306 202 fibers with heat storage properties are described, the storage medium being a paraffinic hydrocarbon or a crystalline plastic and the storage material being integrated in the form of microcapsules in the fiber base material.

In the U.S. patent US 5,728,316 Salt mixtures based on magnesium and lithium nitrate are recommended for the storage and use of thermal energy. The heat is stored in the melt above the melting temperature of 75 ° C.

For the storage media mentioned in latent heat storage takes place during application a transition in the liquid Status. There are problems with the technical use of the storage media in latent heat storage connected because basically must be sealed or encapsulated to allow fluid to escape, which leads to loss of substance or contamination of the environment. This requires especially when used in or on flexible structures, such as fibers, fabrics or foams usually microencapsulation of heat storage materials.

Therefore, a new field of phase change materials with a special focus. It is about firm feast Phase change materials. This group of PCMs already has some Advantages over the solid PCMs. In this way, the problem of volume changes can be largely ruled out.

Numerous PCMs, e.g. salt hydrates, are water soluble Links. This is where the complex and expensive encapsulation process begins.

An object of the present invention was to phase change material into a water resistant matrix bring to. Another task was to make it particularly thin Matrices for Find PCMs.

The tasks were solved by that available making plastic compositions based on thermoplastics, Elastomers or thermoset encapsulated phase change materials containing.

Surprised it was found that phase Change materials embedded in polymers take advantage of encapsulated Have PCMs, e.g. the resistance to water without however the disadvantages of encapsulation, e.g. the elaborate Bring procedural steps.

The use has been advantageous proven by PCMs in elastic polymeric supports, since stresses in the polymeric matrix can be avoided due to volume changes of the PCM during the phase transition occur.

The use has been advantageous proven by firm PCMs in non-elastic polymeric carriers, since stresses in the polymer matrix caused by volume changes of the PCM can be avoided.

The advantage of introducing PCMs in polymers is easy to process. So PCMs in conventional Varnishes are introduced without the processability of the varnishes influence. So that can thin layers are applied, the heat regulating by the contained PCMs Have properties. These new paint systems can be conventional are processed. The paints can e.g. by spraying, brushing, dipping, knife coating, printing, watering or Electrophoresis can be applied.

It was found that the so coated workpieces are able to store heat on their painted surface.

The phase change materials can as well in printing inks, foils or fibers. Here too are all conventional processing techniques (e.g. printing inks: Offset, gravure, flexo or screen printing; Fibers: weaving, knitting; Processing into felts or nonwovens, foils: Thermoforming such as Thermoforming, stretching, stretching, laminating or lamination) applicable.

Thick layers, multiple coatings can also be used and molded parts are made from plastic compositions exist that contain unencapsulated phase change materials.

Due to the wide range of possible applications, the PCMs used also vary greatly. Different PCMs are available for the different applications. PCMs with a phase change temperature between –100 ° C and 150 ° C can be used. Solid PCMs or solid PCMs are used. PCMs selected from the group of paraffins (C ₂₀ -C ₄₅ ), inorganic salts, salt hydrates and their mixtures, carboxylic acids or sugar alcohols are suitable, for example. A selection is summarized in Table 1.

Tabelle 1: Beispiele für fest-fest und fest-flüssig Phasenübergänge

Table 1: Examples of solid-solid and solid-liquid phase transitions

Furthermore, e.g. solid-solid PCMs selected from the group of the dialkylammonium salts, optionally with different Alkyl groups, as well as their mixtures.

Fixed-firm PCMs are particularly selected from the group diethylammonium chloride, dipropylammonium chloride, dibutylammonium chloride, Dipentylammonium chloride, dihexylammonium chloride, dioctylammonium chloride, Didecylammonium chloride, didodecylammonium chloride, dioctadecylammonium chloride, Diethylammonium bromide, dipropylammonium bromide, dibutylammonium bromide, Dipentylammonium bromide, dihexylammonium bromide, dioctylammonium bromide, Didecylammonium bromide, didodecylammonium bromide, dioctadecylammonium bromide, Diethylammmonium nitrate, dipropylammonium nitrate, dibutylammonium nitrate, Dipentylammonium nitrate, dihexylammonium nitrate, dioctylammonium nitrate, Didecylammonium nitrate, diundecylammonium nitrate and didodecylammonium nitrate suitable.

For inorganic solid PCM are preferably added Nucleating agents such as Borax or various metal oxides are used.

The use of encapsulated PCMs in polymeric coatings may be required in some cases. This is e.g. the case when some or all of the PCMs in the polymer soluble are.

As a plastic matrix in which the PCMs can be incorporated the most diverse polymeric materials are used. The Phase change materials are e.g. in polyethylene waxes, polyester, Epoxies, silicones, acrylates, polyurethanes or molding compounds incorporated. Depending on the application, the phase change materials are also converted into conventional ones Lacquer incorporated. The polymer systems are anhydrous, solvent- or water-based dispersions or chemically cross-linking systems.

The plastic compositions contain in addition to the actual heat storage material, if necessary Aids. The aids can be substances or preparations with good thermal conductivity, especially around metal powder, -granulate or graphite. Thereby lies the heat storage material preferably in an intimate mixture with the auxiliaries.

The plastic compositions according to the invention are all characterized by making intimate contact between the phase change material and the component to be tempered out. This can ensure optimal heat conduction guaranteed become.

In addition, binders, preferably a polymeric binder, can be used as the polymeric carrier of the heat storage material. The crystallites of the heat storage material are preferably present in fine distribution in the binder. The preferably polymeric binders that can be contained can be any polymers that are suitable as binders for the intended use. The polymeric binder is preferably selected from curable polymers or polymer precursors, which in turn are preferably selected from the group consisting of polyurethanes, nitrile rubber, chloroprene, polyvinyl chloride, silicones, ethylene-vinyl acetate copolymers and polyacrylates. How the appropriate incorporation of the heat storage materials into these polymeric binders takes place is well known to those skilled in the art. He has no difficulty in finding the necessary additives, such as emulsifiers, for example, which stabilize such a mixture ren.

In addition, other tools and / or Additives, stabilizers and / or solvents in the plastic compositions be included.

With plastic compositions according to the invention equipped materials have a wide range of applications. So they can Phase change materials containing coatings in textile printing for heat storage be used. There are applications for coated textiles in the area of home textiles (e.g. blankets, towels, curtains, etc.) or in Area of the leisure industry (e.g. tarpaulins, sleeping bags, etc.).

Similarly, PCM contained in building protection Plastics are used for temperature control. In wallpaper printing can Coatings can be used just as effectively as with the Glazing. This includes special foils on window glass, conservatory glazing but also greenhouse glazing.

In the applications of the paints according to the invention a broad spectrum is also covered. From car paints to industrial paints can the heat regulating Properties of the PCM-containing paints can be used.

In the food industry, PCM Containing films temper food, and thus the use Reduce or replace complex insulation materials.

Films according to the invention can also be used in the agricultural industry can be used to temper the seeds and plants. The Buffering temperature peaks is an important aspect in the Improve crop yields.

In the electronics industry they can paints according to the invention can be used specifically to temper individual components. applications can be found in power circuits and power circuits for mobile communication, Transmission circuits for Cell phones and fixed transmitters, control circuits for electromechanical Actuators in industrial electronics and in motor vehicles, High frequency circuits for the satellite communications and radar applications, single platinum computers as well for actuators and control devices for household appliances and industrial electronics.

The following examples are intended the invention closer explain, but without limiting it.

example 1

A varnish with the following composition is created:

*Zusammensetzung:

Rub for example on the three-roller mill and add:

*Composition:

Leave with the varnish so produced workpieces made of wood, metal, plasterboard or similar coat.

Example 2

There will be an ink following Composition made: 70 g of nitrocellulose blend ground with 30g PCM (didodecylammonium chloride) and mixed well mixed. The color is changed by adding solvents (e.g. ethyl acetate / propanol / ethoxypropanol) to the desired one Working viscosity adjusted and with additives as required (e.g. wetting aids) added.

Leave with the ink received print on textiles and that contained in the polymer layer PCM works as a heat regulator.

Claims (7)

Plastic compositions containing non-encapsulated Phase change materials, which may contain solvents, stabilizers and / or contain other auxiliaries and additives. Plastic compositions according to claim 1, characterized characterized that the Phase change material is a firm PCM. Plastic compositions according to claim 2, characterized characterized that the Phase change material is a dialkyl ammonium salt. Use of plastic compositions according to claim 1-3 for Temperature control and / or heat conduction and / or heat storage. Use of plastic compositions according to claim 4 for the production of coatings. Use of plastic compositions according to claim 5 in which the coatings varnishes, printing inks and foils contain water-containing, solvent-based or water-free dispersions or chemically cross-linking polymer systems are. Use of polymer-containing coatings according to claim 5 in textile printing, wallpaper printing, in industrial paints, in automotive paints and in building protection.