EP2298669A1 - Cartridge with integrated device for heating a melting adhesive and method for using the cartridge - Google Patents

Abstract

The cartridge (1) is filled with a hot melt adhesive, where the cartridge is formed with an outlet opening (7) with a base (11) and a cartridge head (2) in a cylindrical manner. A heating element is provided and is embedded in the hot melt adhesive. The hot melt adhesive is a reactive hot melt adhesive, which is made of polymers with isocyanate groups. The non-reactive hot melt adhesive contains a thermoplastic material which is selected from the group of thermoplastic polyurethanes, polyesters, polyamides, and homo-or copolymers of unsaturated monomers. The cartridge is made of aluminum. An independent claim is also included for a method for manufacturing a cartridge.

Description

Technical area

The invention relates to a cartridge with integrated device for heating a hotmelt adhesive, consisting of a filled with a hot melt adhesive cartridge, the cartridge is cylindrical with a bottom and a cartridge head with a filling opening is designed, and a method of using such a cartridge. Furthermore, the invention relates to a method for using a heatable cartridge.

State of the art

Hotmelt adhesives, also abbreviated to HM (= hot melt), are solvent-free products which are virtually solid at room temperature and are based on various chemical raw materials, such as various polyols, polymers and elastomers.

A distinction is made between non-reactive and reactive hot melt adhesives. Non-reactive hot melt adhesives are thermoplastic adhesives that achieve their adhesive effect and strength solely by changing the state of aggregation from liquid to solid during the cooling process. By reheating the adhesive bond can be solved again. In contrast, reactive hot-melt adhesives additionally react chemically and then form a thermoplastic elastomer, which can no longer be completely melted by the action of heat.

For gluing two surfaces of the hot melt adhesive is applied to the adhesive surfaces in the hot state and then establishes a connection between the surfaces to be bonded during cooling. The melting point is typically dependent on the composition in the range between 80 ° C and 200 ° C. If in the following text is written by a heating of the hot melt adhesive, then a heating of the hot melt adhesive to the application temperature is just above the Melting temperature meant, since already here the desired properties of the hot melt adhesive occur.

Hot melt adhesives generally allow fast work processes without lengthy dry processes of the adhesive. The fields of application of hot melt adhesives are diverse, but mainly found in the industry. Typical applications are, for example, in the automotive industry in the bonding of gaskets, in the textile industry in the bonding of materials, in the packaging industry for gluing envelopes, as well as the furniture and construction industry for lamination.

A disadvantage of the use of hot melt adhesives is the relatively complex processing of these substances with expensive equipment for heating and keep the temperature of the hot melt adhesive. In addition, the reactive hot melt adhesives must be protected from moisture during storage and before or during processing, since the reactive isocyanate groups of the hot melt adhesive otherwise react, for example with the humidity and the hot melt adhesive can not then be melted, that is useless. This means a lot of effort in the packaging of hot melt adhesives. Typical packaging and storage are air-tight and watertight aluminum cartridges.

These problems - complex processing with expensive equipment and high packaging costs for protection against moisture - make use by private consumers or use in the non-industrial sector almost impossible or unprofitable.

Furthermore, cartridge guns for applying hot melt adhesives or other tough materials such as silicone are known, wherein the adhesive or material is pressed out by means of a special printing device from the cartridge. Normally, this is done by the bottom of the cartridge, which is designed as a movable piston, is pressed in the application inward and so presses the adhesive or material through the outlet opening at the cartridge head out. The outlet opening is usually closed with an aluminum foil, alternatively or additionally by a screw cap, or is designed in such a way that there the material thickness is thin and can be easily penetrated.

Special cartridge guns with which the processing of a hot-melt adhesive is possible additionally have the option of heating the hot-melt adhesive with the aid of a heater installed in the cartridge gun. As a result, these devices are very complicated and expensive.

Previous approaches to the simplified processing of hot melt adhesives are not known.

Presentation of the invention

It is therefore an object of the invention to find a cost-effective and simple solution, so that hot melt adhesives are profitable and easy to use for private consumers.

This object is solved by the features of the independent claims. Advantageous developments of the invention are the subject of the subordinate claims.

Ways to carry out the invention

The inventors have recognized that a simple and cost-effective processing of hot melt adhesives - this applies to both reactive and non-reactive hot melt adhesives - for private users is possible. This can be accomplished by providing the hot melt adhesive in a special disposable packaging which, on the one hand, meets all the necessary storage conditions and, on the other hand, enables the necessary application temperature of the hot melt adhesive to be achieved. Thus, it is then possible to use a hot melt adhesive in combination with a commercial and inexpensive cartridge gun without special heater.

A disposable packaging for hot melt adhesives according to the invention corresponds, for example, to an airtight cartridge, for example made of aluminum, in which a heating device, which can bring the hot melt adhesive to the application temperature, is additionally integrated. It is the Heating device embedded directly in the hot melt adhesive, so that as even as possible heating of the material can be guaranteed.

If the hotmelt adhesive has reached its application temperature, the heating device, for example an elongate heating wire, according to a variant of the invention can be removed from the hotmelt adhesive and the cartridge used for processing in a caulking gun. In another variant, a processing of the hot melt adhesive without prior removal of the heater, such as a heating coil, possible. Such a heating coil can either be arranged on the side of the cartridge or embedded in the hot-melt adhesive.

According to this basic idea, the inventors propose a cartridge with an integrated device for heating a hot-melt adhesive, consisting of a cartridge filled with a hot-melt adhesive, wherein the cartridge is configured cylindrically with a bottom and a cartridge head with a filling opening, in that at least one provided in the hot melt adhesive heating element is provided.

A variant of the invention provides that the at least one heating element is removed from the cartridge before processing of the hotmelt adhesive. It is particularly important to ensure that this fits easily through the outlet opening on the cartridge head. Advantageously, an elongated heating wire is suitable for this purpose.

Furthermore, it is advantageous if the heating wire has a fastening element which can be fixed to the outside of the cartridge. This may be, for example, a screw cap which can be easily screwed on and unscrewed onto a screw thread on the outside of the cartridge head. Thus, on the one hand, the cartridge can be closed and, on the other hand, it is possible for the heating wire to be easily pulled out of the cartridge. Particularly advantageous in this embodiment is that the heating element is easy on the inside of the lid can be fixed without the function of the lid or the heating element would be affected.

Alternatively, the at least one heating element may also be a microwave generator which heats the hotmelt adhesive by microwaves, this alternative being certainly less preferred in the context of a one-way system for reasons of cost.

A further variant of the invention consists in that the at least one heating element is a heating spiral, which consists of an elastic material. The advantage of this variant is that the heating coil can remain in the cartridge during processing. In order to squeeze the adhesive out of the cartridge, the cartridge can be clamped in a caulking gun, in which case a stamp presses the bottom of the cartridge inwards via a lever system and thus the adhesive is forced out through the filler opening. The heating coil is then simply compressed by the punch or the cartridge bottom. A particular advantage of this variant is that the reactive hot-melt adhesive does not come into contact with atmospheric moisture before application, since the interior of the cartridge need only be opened immediately before application and not for removal of the heating device.

To operate the heating element, it is advantageous to connect it to a power source. As a power source can be, for example, an external power source, in which case the connection is advantageously in a cable with a simple plug connection, wherein further advantageously a transformer is provided which can ensure that the heater can be operated with a safe voltage of, for example, 12V.

Alternatively, as a power source, a battery can be used. This is particularly advantageous in terms of flexibility of the site is here a battery, since the user is not dependent on the proximity of a power outlet.

According to the invention, the hot-melt adhesive described may be both a reactive and a non-reactive hot-melt adhesive. Reactive hotmelt adhesives usually contain at least one polyurethane prepolymer having isocyanate groups, which is prepared by reacting suitable polyols, in particular polyesterpolyols, with an excess of diisocyanates. Non-reactive hot melt adhesives advantageously contain a thermoplastic material which is selected from the group consisting of thermoplastic polyurethanes, polyesters, polyamides and homopolymers or copolymers of unsaturated monomers. The monomers for the homo- or copolymers of unsaturated monomers are especially selected from the group consisting of ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or higher esters thereof, and (meth) acrylate. Particularly suitable are ethylene-vinyl acetate copolymers (EVA), atactic poly-α-olefins (APAO), polypropylenes (PP) and polyethylenes (PE). Preferably, the thermoplastic material is an ethylene vinyl acetate copolymer (EVA) or an atactic poly-α-olefin (APAO).

Depending on the substance groups used, there are advantages that can be exploited as a result of the application or process. The various compositions make it possible to combine certain advantages and / or to minimize disadvantages.

Optionally, it is also possible to equip the cartridge with a measuring device for measuring the temperature of the hot melt adhesive so that the temperature of the hot melt adhesive can be checked during heating. It is also possible via a control or feedback mechanism (usually via a computer control) to couple the heating power and the temperature so that the temperature remains at a desired and adjustable value. The optimum application temperature is reached when the hot melt adhesive is at least partially liquefied. The viscosity at the application temperature should be such that the hot melt adhesive is sufficiently fluid to be easily applied, but not so deep viscosity that it will flow away from the workpiece to be bonded.

To further make the application and use of the cartridge according to the invention flexible, it is advantageous to provide the cartridge in different sizes. This allows the end user, depending on the size of his project, to decide which portion size of the hot melt adhesive he needs. This means further cost savings and ease of use. Alternatively, a variable filling amount of the adhesive in the cartridge can also be achieved by a different positioning of the cartridge bottom within the cartridge, since the cartridge bottom is pushed into the cartridge for squeezing anyway. In the variant with the heating wire, it is of course necessary to adjust the length of the wire. This can be done, for example, by shortening the wire or by moving the wire through a clamping or holding device located in the kartsaw. Especially with non-reactive hot melt adhesives, it is possible and inexpensive to reheat an inserted cartridge at a later time by reusing the heating element and to use up the hot melt adhesive from this cartridge.

Advantageously, the cartridge can be made of aluminum, since this material has good thermal conductivity properties.

1. i) Erhitzen des Schmelzklebstoffs in der Kartusche mit Hilfe des Heizelements;
2. ii) Montage der Kartusche mit dem erhitzten Schmelzklebstoff auf eine Kartuschenpistole;
3. iii) Applikation des Schmelzklebstoffes.

The invention further relates to a method of using a cartridge with a heating device, comprising the following method steps:

1. i) heating the hotmelt adhesive in the cartridge by means of the heating element;
2. ii) mounting the cartridge with the heated hot melt adhesive on a caulking gun;
3. iii) Application of the hotmelt adhesive.

When using a heating element, which does not remain in the cartridge during the application, so for example a heating wire according to the invention, it is useful to remove this heating wire from the hot melt adhesive before application. If applicable, this also applies to a closure of the outlet opening on the cartridge head.

Brief description of the drawings

In the following the invention will be described in more detail by means of a preferred embodiment with the aid of the figures, wherein it is pointed out that only the elements essential for the immediate understanding of the invention are shown. Identical elements are identified in the various figures with the same reference numerals. It should also be noted that the figures shown here are schematic representations without size references.

FIG. 1:

Kartusche mit Schraubgewinde;

FIG. 2:

Heizdraht;

FIG. 3:

Kartusche mit integriertem Heizdraht;

FIG.4:

Flussdiagramm des erfindungsgemäßen Verfahrens zum Erhitzen eines Schmelzklebstoffs mit Hilfe eines Heizdrahtes;

FIG. 5:

Kartusche mit integrierter Heizspirale;

FIG.6:

Momentaufnahme einer Kartusche mit integrierter Heizspirale während der Verarbeitung.

They show in detail:

FIG. 1:

Cartridge with screw thread;

FIG. 2:

heating wire;

FIG. 3:

Cartridge with integrated heating wire;

FIG.4:

Flowchart of the method according to the invention for heating a hot melt adhesive by means of a heating wire;

FIG. 5:

Cartridge with integrated heating coil;

FIG.6:

Snapshot of a cartridge with integrated heating coil during processing.

The FIG. 1 shows a cartridge according to the invention 1. The cartridge 1 has a cylindrical shape with a bottom 11 and a cartridge head 2. The cartridge head 2 has an outlet opening 7 through which the hot melt adhesive can be pressed out during processing by pressing the bottom 11 into the cartridge , Such a cartridge 1 is filled at its end opposite the cartridge head 2 before the bottom 11 is inserted.

In this embodiment, the cartridge head 7 additionally has on its outside a screw thread 6, which serves for fastening a screw cap connected to the heating device. It is also possible to screw a nozzle onto this thread when applying the adhesive.

The heater - see FIG. 2 - In this variant consists of an elongated heating wire 4 and the screw 5. The heating wire 4 can be attached to the inside of the screw 5. In the design of the screw cap should be taken to ensure that it can close the cartridge airtight.

It is important in the design of the heating wire 4 that it can be easily guided through the outlet opening of the cartridge head and extends as far as possible over the entire height of the cylindrical cartridge, so that a uniform heating of the hot melt adhesive takes place.

This is in the FIG. 3 clearly visible. Here is a cartridge 1 with screwed-on screw 5 and axially positioned heating wire 4 is shown. The heating wire 4 extends here almost over the entire height of the cartridge. 1

In the FIG. 4 a flow chart of the method according to the invention for the use of an inventively heated cartridge 1 is shown. The method is used here on the variant according to FIGS. 1 to 3 described by way of example. In the first step 101 of the method, the hot melt adhesive in the cartridge 1 is heated. For this purpose, the heater is connected to a power source. For example, this may be an external power source 8, wherein an intermediate transformer 9 can regulate the usual voltage from 220 V to 12 V down.

In addition, a temperature measuring device not shown here can measure the temperature of the hot melt adhesive continuously or at short intervals. Once it has reached the application temperature of the hot melt adhesive, the heating process is completed.

Next - step 102.1 and 102.2 - the entire heater is removed. This is done by unscrewing the screw 5 and pulling out the heating wire 4. Now, the cartridge 1 can be mounted on the cartridge gun 10 in step 103. The exemplary cartridge gun 10 shown here is a so-called skeleton gun. It is available in various sizes commercially, so that different sized cartridges 1 can be used with different portions of the hot melt adhesive. The hotmelt adhesive may be extruded therefrom and processed by means of a die of the caulking gun which acts on the bottom of the cartridge 1 - step 104. Exemplary uses include gluing gaskets or laminating wood panels.

In the FIGS. 5 and 6 a further variant of the heating device according to the invention is shown. This is a heating coil 3, which is embedded in the hot melt adhesive - see FIG. 5 , The heating coil 3 is also connected via an intermediate transformer 9 to a power source 8. After heating the hot melt adhesive, the heating coil 3 remains in the cartridge 1. To press out the adhesive from the outlet opening 7 of the bottom 11 of the cartridge 1 is pressed into this - see FIG. 6 , In this case, the elastic spiral 3 deforms, so it is compressed in the direction of the outlet opening 7.

It is understood that the abovementioned features of the invention can be used not only in the respectively specified combination but also in other combinations or in isolation, without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

cartridge

2

cartridge head

3

heating coil

4

heating wire

5

screw

6

screw thread

7

outlet opening

8th

power source

9

transformer

10

caulking gun

11

ground

101

Heating the hot melt adhesive

102.1

Remove the heating element

102.2

Remove the closure

103

Assembly of the cartridge on a caulking gun

104

Applying the hot melt adhesive

Claims (15)

Cartridge (1) with integrated device for heating a hotmelt adhesive, consisting of: a cartridge (1) filled with a hotmelt adhesive, the cartridge (1) being configured in a cylindrical manner with a base (11) and a cartridge head (2) with an outlet opening (7),
characterized in that at least one embedded in the hot-melt adhesive heating element (3, 4) is provided. Cartridge (1) according to the preceding claim 1,
characterized in that
the at least one heating element is a heating wire (4). Cartridge (1) according to the preceding claim 2,
characterized in that
the at least one heating wire (4) has a fastening element. Cartridge (1) according to the preceding claim 2,
characterized in that
the fastener is a screw cap (5). Cartridge (1) according to the preceding claim 4,
characterized in that
the cartridge head (2) on the outside has a screw thread (6) onto which the screw cap (5) can be screwed. Cartridge (1) according to the preceding claim 1,
characterized in that
the at least one heating element is a heating coil (3). Cartridge (1) according to the preceding claim 6,
characterized in that
the heating coil (3) consists of an elastic material. Cartridge (1) according to one of the preceding claims 1 to 7, characterized in that
the heating element (3, 4) has a connection to a power source (8). Cartridge (1) according to one of the preceding claims 1 to 8, characterized in that
the hot-melt adhesive is a reactive hot-melt adhesive which contains, in particular, polymers having isocyanate groups. Cartridge (1) according to one of the preceding claims 1 to 8, characterized in that
the hot melt adhesive is a non-reactive hot melt adhesive. Cartridge (1) according to the preceding claim 10,
characterized in that
the non-reactive hot melt adhesive comprises a thermoplastic material selected from the group consisting of thermoplastic polyurethanes, polyesters, polyamides and homo- or copolymers of unsaturated monomers. Cartridge (1) according to one of the preceding claims 1 to 11, characterized in that
a measuring device is provided for measuring the temperature of the hotmelt adhesive in the cartridge (1). Cartridge (1) according to one of the preceding claims 1 to 12,
characterized in that
the cartridge (1) is made of aluminum. Method for using a cartridge (1) according to the preceding claims 1 to 13, comprising the following method steps: i) heating (101) the hotmelt adhesive in the cartridge (1) by means of the heating element (3, 4), ii) mounting (103) the cartridge (1) with the heated hot melt adhesive on a cartridge gun (10), iii) applying the hot melt adhesive (104). Method according to the preceding claim 14,
characterized in that
the heating wire (4) is removed from the hotmelt adhesive (102.1) and / or the closure (5) of the cartridge head (2) (102.2).

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