WO2011067182A1

WO2011067182A1 - Sales unit for a reactive hot-melt adhesive, and method for the use thereof

Info

Publication number: WO2011067182A1
Application number: PCT/EP2010/068331
Authority: WO
Inventors: Johannes Schulze
Original assignee: Sika Technology Ag
Priority date: 2009-12-04
Filing date: 2010-11-26
Publication date: 2011-06-09
Also published as: EP2330052A1; EP2507145A1

Abstract

The invention relates to a sales unit for a reactive hot-melt adhesive (1), wherein the reactive hot-melt adhesive (1) is present loosely in individual portions in a wrapping (2, 5) which is sealed in relation to liquid water, in particular in relation to water vapour, and each portion has a mass and form in which the portion requires a maximum of two minutes for melting in an air stream having a temperature between 100°C and 180°C. The invention also relates to a method for using a reactive hot-melt adhesive (1), containing the following method steps: a. removing one or more portions of the reactive hot-melt adhesive (1) from the wrapping (2, 5), b. applying the one or more portions of the reactive hot-melt adhesive (1) to a substrate, c. melting the one or more portions of the reactive hot-melt adhesive (1), and d. pressing a counter-substrate onto the substrate with the liquid reactive hot-melt adhesive (1).

Description

SALES UNIT OF A REACTIVE MELT ADHESIVE AND METHOD OF USE

Technical area

The invention relates to a sales unit of a reactive

Hot melt adhesive, and a method of use.

State of the art

Reactive hot melt adhesives, also abbreviated RHM (= reactive hot melt) called, are known. These are solvent-free and almost solid at room temperature. They usually consist of isocyanate-terminated

Polyurethane prepolymers, which are prepared by reacting suitable polyols with an excess of diisocyanates. The fields of application of reactive hot melt adhesives are diverse, but mainly found in the industry. Typical applications are found, for example, in the automotive industry, in the textile industry, in the

Packaging industry, as well as in the furniture industry. To bond two surfaces, the reactive hot melt adhesive is applied to the adhesive surfaces in a hot state. It builds up immediately after its application by cooling a high initial strength. Its final properties, in particular heat resistance and resistance to environmental influences, the reactive hot melt adhesive receives by a chemical reaction, which leads to a gradual curing by reacting isocyanate groups with atmospheric moisture. reactive

Hot melt adhesives combine the advantages of fast setting

Hotmelt adhesives with those of chemically crosslinking adhesives. So they cure quickly and their adhesive bond can not be solved by simply heating again.

The strong reactivity of the hotmelt adhesive with water, for example with atmospheric moisture, is the storage and packaging of the Hot melt adhesives disadvantageous. 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 with the humidity and crosslink, so that the hot melt adhesive can not be melted afterwards, so it is useless. This means both a high cost and material costs in the packaging of hot melt adhesives.

Previously known packages that exclude both liquid water and humidity are, for example, air and watertight

Cartridges made of aluminum or plastics. In this regard, reference is made to International Publication WO 2006/051 1 18 A1.

Another disadvantage of the processing of these adhesives is the necessary heating, or melting, before use. The melting point is usually at temperatures up to 150 ° C, depending on the composition of matter. If in the following text of a heating of the adhesive is written, it is meant a heating of the hot melt adhesive to the application temperature just above the melting point, since already here the desired properties of the hot melt adhesive, so sufficiently low viscosity for easy application occur.

With conventional cartridge sizes of, for example, 330 grams or more, the melting of the hot melt adhesive takes up to 30 minutes. Only then the material has reached its suitable processing temperature and can be applied to the surfaces to be bonded. The temperature used for melting are limited by the material properties of the hot melt adhesive, since the hot melt adhesive at

Temperatures from about 200 ° C decomposes or burns, and thus becomes unusable. It is therefore not possible to shorten the time required for melting by simply increasing the applied temperature as desired. Due to the relatively long waiting period, the use of reactive hot melt adhesives is inflexible. For melting are usually special Processing equipment used, which can both heat the hot melt adhesive and process afterwards. However, these special devices are expensive and expensive. In addition, the cartridges are packages that allow only a single use of the hot melt adhesive. In the case of discontinuous applications or if the amount of hot melt adhesive contained in a cartridge is not completely consumed in one application, a tremendous waste of material is created.

These problems make use by private consumers, or use in the non-industrial sector, almost impossible or unprofitable. Previous approaches to simplified processing of

Hot melt adhesives are not known.

Presentation of the invention

It is therefore an object of the invention to find a way to make reactive hot melt adhesives easy and inexpensive for private users.

This task is characterized by the characteristics of the independent

Claims solved. Advantageous developments of the invention are the subject of the subordinate claims.

The inventor has recognized that the key issues that make the use of reactive hot melt adhesives in the private sector unprofitable are that processing with specialized equipment is both cumbersome and inflexible due to the long wait times, and that the ones currently on the market remain Portion sizes too big and too expensive for some small repairs, such as a broken table leg. These problems can be solved with the help of alternative packaging and portioning of the hotmelt adhesive and thereby possible

alternative methods for melting the hot melt adhesive are solved, so that the application is fast and flexible, without expensive special equipment and waste of material is possible.

The alternative packaging of the hotmelt adhesive consists of a simple watertight and also water vapor-tight envelope, in which the hotmelt adhesive is packaged individually, in portions and loosely. Under the

The term "loose" is understood here to mean that the hot melt adhesive portions are not in any further packaging than in the tight envelope, which does not necessarily have to rest against the hot melt adhesive portions , namely a maximum of 2 minutes in an air stream at a temperature between 100 ° C and 180 ° C, in particular for a maximum of one minute at a temperature between 120 ° C and 150 ° C. The applied temperature is limited to the top, since above this temperature of the The limitation downwards is of course based on the melting temperature of the hotmelt adhesive, which means that ideal portion sizes in compact portions have a weight of approximately 1-10 grams, but this depends on the shape of the portions one

essential factor. For example, a very flat portion at the same temperature melts faster than a compact portion with the lowest possible surface area. A platelet only 1 -2 mm thick with a large surface area - similar to a hotmelt adhesive film - thus fulfills the condition regarding the

Melting time as well as a larger diameter bead but smaller surface area. In any case, according to the above

illustrated provision determine the inventive portion size with the help of a few experiments depending on the specific adhesive used. In principle, however, the person skilled in the art can also change the portion size using known geometric shapes, known Wärmeleit- and

Calculate heat transfer coefficients.

For gluing two surfaces, the required number of

Hot melt adhesive portions are acutely removed from the enclosure and positioned directly on the substrate to be bonded. The positioning on inclined surfaces can be greatly facilitated as part of the hot melt adhesive by the use of so-called tackifiers, since such a reactive hot melt adhesive and thus the

Hot melt adhesive portions are slightly sticky at room temperature.

Instead of the time-consuming melting with expensive special equipment, it is possible in the present invention to heat the hot melt adhesive portions directly and quickly at the point to be bonded. It can be used any heat generating devices that provide the necessary heat, such as a hot air device, a soldering iron or an infrared or

Microwave. Once the hot melt adhesive has completely melted, the counter substrate can be positioned on the liquid hot melt adhesive and the usual curing process consolidates the bond.

The heat generating devices are preferably coupled to thermostats and / or thermocouples and thereby preferably can set a desired temperature in the adhesive.

The main differences between the use of conventional hot melt adhesives packaged in cartridges and the individually packaged hot melt adhesives are thus the low melt relationship or waiting time and the ability to apply the hot melt adhesive in portions before melting on the adhesive surfaces.

There are various possibilities for the execution of the water and water vapor-tight envelope. For example, this can be from a

Metal foil with coating or without coating or a plastic film, alternatively also made of a plastic-aluminum-laminate film exist. These can either be in the form of so-called blister packs as they are made from Pharmaceutical industry are known for packaging of tablets, or in the form of conventional bags.

The portion-wise packaging of the hot melt adhesive and the simple and above all rapid heating thus make the application of

Hotmelt adhesives are attractive and profitable in the private sector as well.

According to this basic idea, the inventor proposes one

Sales unit of a reactive hot melt adhesive, wherein the reactive hot melt adhesive in portions individually and loosely in a liquid

Water tight, especially a tight against steam, wrapping is present and each serving has a mass and shape in which the portion in an air stream with a temperature between 100 ° C and 180 ° C for

Melting takes a maximum of two minutes.

It is more favorable to use a hot-melt adhesive portion which melts in an air stream with a temperature between 120 ° C and 150 ° C within only one minute. From the conditions relating to the melting time and temperature, advantageous portion masses of the hotmelt adhesive of approximately 1-10 grams result in a compact portion form. Advantageous Portionsformen are for example beads, tablets or sticks, or platelets. In the case of platelets, it is particularly advantageous if they are no thicker than 0.5 to 2 mm at any point. As a result, it is also very easy to set an optimum covering thickness of a splice with adhesive for the gluing process.

In one embodiment of the invention, the envelope consists of a film. This is preferably a metal foil, in particular an aluminum foil, furthermore in particular a polyethylene foil coated with aluminum foil. Alternatively, a plastic film is possible. Furthermore also fulfills a combination of a plastic and Aluminum in the form of a plastic-aluminum laminate foil the required conditions.

A further preferred embodiment provides that the individual hot melt adhesive portions are packed in blister packs, with exactly one portion being present in each bubble. This type of packaging is already known from the pharmaceutical industry for water and water vapor-tight packaging of tablets, such a blister pack does not necessarily have to be transparent and thus translucent. The

Portion pieces can be made simply by pushing a bubble out of the

Blister pack be removed.

In an alternative embodiment, the water-in particular water vapor-tight enclosure is a bag. It is advantageous and easy to use, when the enclosure has a tearing open for easy opening. This can be for example an integrated tear tape or a notch.

In the case of a blister pack, the number of hot melt adhesive portions in a sales unit is defined by the number of blisters in which the individual portions are contained, whereas in the case of packaging in bags a sales unit corresponds to one bag each with a loosely packed portion, whereby it is also possible To connect several bags and thus take together to form a sales unit. In this case, the hot melt adhesive may be present in all possible forms, for example in tablet or

Bead form.

To in the bag, or the blister pack, a

To create completely moisture-free environment, they can either be vacuum-packed or rinsed with an inert and steam-free gas, for example nitrogen or inert gas, during packaging. Advantageously, the reactive hot melt adhesive contains at least one isocyanate-terminated polyurethane prepolymer, which is prepared by reacting suitable polyols with an excess of diisocyanates. Suitable polyols are in particular polyester polyols in question. Particular preference is given to polyester polyols which are solid at room temperature. The reactive hot melt adhesive preferably has a melting point between 80 and 140 ° C, in particular between 80 and 100 ° C, on.

Another embodiment provides that the reactive

Hot melt adhesive contains a tackifier (= tackifier). As a result, the surfaces of the adhesive portions are already tacky without melting. And able to adhere to a substrate surface. This can greatly facilitate gluing on inclined surfaces, since it is no longer necessary

Hold the adhesive portion by hand until it is sufficient

is melted.

Furthermore, the invention relates to a method for using a hot melt adhesive packed in portions according to the invention, which comprises the following method steps:

a. Take one or more portions of the reactive

Hotmelt adhesive from the envelope,

b. Apply one or more portions of the reactive

Hot melt adhesive to a substrate,

c. Melt the one or more portions of the reactive

Hot melt adhesive, and

d. Pressing a Gegensubstrates on the substrate with the liquid reactive hot melt adhesive.

The steps a, b, c and d are preferably carried out in the listed here

Order one after the other.

For melting the reactive hot melt adhesive, any heat generating equipment can be used, which provide the necessary temperature above the melting temperature. These are for example one Hot air device, an infrared or microwave applicator or a mechanical contact with a heating element, such as a soldering iron.

Brief description of the drawings

In the following, the invention will be more preferred with reference to several

Embodiments with reference to the figures described in more detail, it being noted that only the essential elements for the immediate understanding of the invention are shown. Same elements are in the

various figures marked with the same reference numerals. Furthermore, the figures shown here are purely schematic

Representations.

They show in detail:

FIG. 1 top view of a blister pack with hot melt adhesive portions;

FIG. 2 cross section of a blister pack with hot melt adhesive portions;

FIG. 3 bags with a portion of hot melt adhesive;

FIG. 4 cross section of a bag with a hot melt adhesive portion;

FIG. 5 sales unit of four bags;

FIG. 6 Flow chart of the inventive method.

There are several variants of the portions of the reactive

Hot melt adhesive water and especially water vapor-tight packaging. A variant is shown in FIG 1. Here, a plan view of a blister pack 2 with a plurality of bubbles 3 is shown. In the bubbles 3 is in each case loose, so without any other envelope, a single tablet-shaped portion of the

Hot melt adhesive 1. The portion size can advantageously be between 1 and 10 grams. These sizes are particularly suitable for use, since they can usually be completely used up by a private user with an application and thus no material is wasted. If several portions of the hotmelt adhesive 1 are required for a larger application, it is of course always possible to take several portions and use according to the method described. For such blister packs 2, especially a plastic aluminum laminate foil is suitable. In this case, there are usually the bubbles 3 and the material connecting the bubbles 3 of a slightly stronger plastic film, in particular of a plastic molding, and from a dense

Closure of the bubbles 3 laminated waterproof top layer,

in particular from an aluminum foil, a coated aluminum foil or a transparent plastic foil. In this case, the plastic molding both transparent and not transparent, for example, coated, be executed. A coating can render the package opaque, thereby improving the durability of the reactive hot melt adhesive.

In a wrapping of the hot melt adhesive portions 1 in a

Blister pack is a sales unit by a blister pack - here with 12 individually loosely packed hot melt adhesive portions 1 - formed.

FIG. 2 once again shows a blister pack 2 in cross-section. In this case, the bubbles 3 with the hot melt adhesive portions 1 loosely contained therein can be seen particularly well. To remove the

Hot melt adhesive portions 1, the bladder 3 can be pressed inward and the hot melt adhesive 1 thus by the cover layer 4, for example, aluminum, pressed.

FIG. 3 shows another variant of the envelope of FIG

Hot melt adhesive portions 1. A bag 5 is shown, in which a single platelet-shaped portion of the hot-melt adhesive 1 is contained. For easy removal of the hot melt adhesive portions 1, the bag 5 shown here has a tear strip 6.

FIG. 4 shows a cross section of the bag 5 from FIG. 3. The very flat shape of the bag is particularly well recognizable

Hot melt adhesive portion 1. With such a portion shape 1 with a single hot melt adhesive portion 1 much larger adhesive surfaces can be covered than, for example, with a tablet-shaped portion, as it is shown in Figures 1 and 2, without the liquid hot melt adhesive would have to be spread on the adhesive surface. Thus, a more economical handling of the material is possible. FIG. 5 shows an alternative sales unit consisting of four interconnected bags each having a hot melt adhesive portion 1 according to the bag 5 shown in FIG. The individual bags 5 can be connected by a connecting seam 1 1. FIG. 6 shows a flowchart of the invention

Method for using a hot melt adhesive or water vapor tightly packed hot melt adhesive 1. First (step a) is the appropriate number of required

Hot melt adhesive portions 1 - in the picture shown here exactly one - from the blister pack 2 by pressing the bubbles 3 and thus tearing the

Dirt layer 4 removed. The use of reactive hot melt adhesives 1 in the private sector is varied, for example, the repair of a table 7 with broken table leg 8. For this purpose, the hot melt adhesive 1 is placed on the substrate with the surfaces to be bonded 9 - dashed lines here

marked (step b).

For melting the hot-melt adhesive 1, for example, a hot-air device 10 can be used (step c). Here, the small portion size of the hot melt adhesive has a positive effect, since the suitable processing temperature is reached very quickly. To melt a portion 10 at a temperature between 120 ° C and 180 ° C in the air stream of Heissllgerätes 10 is not required more than 2 minutes. The melting point of reactive hotmelt adhesives is between 70 ° -90 ° C, depending on the composition of the material.

Once the suitable processing temperature of the hot-melt adhesive 1 has been reached, the counter-substrate with the second adhesive surface-in this case the broken table leg 8-can be placed in the now-liquid hotmelt adhesive 1 the first adhesive surface 9 are pressed against the table 7 (step d). Once the hot melt adhesive 1 is completely cured, the adhesive bond is stable.

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 hot melt adhesive

2 blister pack

3 bubbles

4 cover layer

5 bags

6 tear tape

7 table

8 table leg

9 adhesive surface

10 hot air device

1 1 seam

Claims

claims

1. Sales unit of a reactive hotmelt adhesive (1), wherein the reactive hotmelt adhesive (1) in portions individually and loosely seal in a liquid against water, in particular a dense against water vapor,

Envelope (2, 5) is present and each serving has a mass and shape in which the portion in a stream of air at a temperature between 100 ° C and 180 ° C for melting takes a maximum of two minutes.

2. Sales unit according to the preceding claim 1,

characterized in that

a portion in an air stream with a temperature between 120 ° C and 150 ° C for melting a maximum of one minute needed.

3. Sales unit according to one of the preceding claims 1 to 2, characterized in that

one serving has a mass of 1-10 grams.

4. Sales unit according to one of the preceding claims 1 to 3, characterized in that

the envelope (2, 5) of a metal foil, in particular a

Aluminum foil, in particular a coated aluminum foil,

in particular a polyethylene coated aluminum foil. 5. Sales unit according to one of the preceding claims 1 to 3, characterized in that

the envelope (2,

5) consists of a plastic film.

6. Sales unit according to one of the preceding claims 1 to 5, characterized in that

the envelope (2, 5) consists of a plastic-aluminum laminate foil.

7. Sales unit according to one of the preceding claims 1 to 6, characterized in that

the wrapping is a blister pack (2).

8. Sales unit according to one of the preceding claims 1 to 6, characterized in that

the wrapping is a bag (5).

9. Sales unit according to the preceding claim 8,

characterized in that

the bag (5) has a tearing device for opening.

10. Sales unit according to the preceding claim 9,

characterized in that

the tearing device has an integrated tear strip (6).

11. Sales unit according to the preceding claim 9,

characterized in that

the tearing device has a notch in the bag (5).

12. Sales unit according to one of the preceding claims 1 -11, characterized in that

the reactive hot melt adhesive (1) contains at least one isocyanate-terminated polyurethane prepolymer which is prepared by reacting suitable polyols with an excess of diisocyanates.

13. Sales unit according to one of the preceding claims 1 -12, characterized in that

the reactive hot melt adhesive contains a tackifier.

14. A method for using a reactive hot melt adhesive (1) according to one of the preceding claims 1 to 13, comprising the following method steps:

a. Take one or more portions of the reactive

Hot melt adhesive (1) from the envelope (2, 5),

b. Apply one or more portions of the reactive

Hotmelt adhesive (1) on a substrate,

c. Melt the one or more portions of the reactive

Hot melt adhesive (1), and

d. Pressing a Gegensubstrates on the substrate with the liquid reactive hot melt adhesive (1).

15. Method according to the preceding claim 14,

dad u rch nze i net that

a device from the following list is used for melting: hot air device (10), infrared applicator, microwave applicator, heating element with heating surface for mechanical contact with the adhesive.