EP1689841A1

EP1689841A1 - Cleaning agent composition

Info

Publication number: EP1689841A1
Application number: EP04804571A
Authority: EP
Inventors: Violetta Wenck; Kai Paschkowski
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2003-11-25
Filing date: 2004-11-25
Publication date: 2006-08-16
Also published as: WO2005052104A1; EP1535990A1

Abstract

The invention relates to a cleaning agent composition for reactive polyurethane melt adhesives, comprising at least one carrier medium (A) without NCO-reactive groups, and at least one compound (B) with an NCO-reactive group, and a monofunctional amide or a monofunctional imide. The invention also relates to a method which is used to clean application systems and devices of reactive polyurethane melt adhesives, and to a method for the production and use of a cleaning agent composition which is used to remove reactive polyurethane melt adhesives from application systems or application devices.

Description

DETERGENT COMPOSITION

TECHNICAL FIELD The present invention relates to cleaning agents for cleaning processing plants from reactive polyurethane hotmelt adhesives.

PRIOR ART When reactive polyurethane hotmelt adhesives are processed, adhesive particles which have hardened over time always occur due to the reactivity with water, in particular in the form of atmospheric moisture, which adversely affect the quality and application. That is why regular cleaning of the systems and equipment is necessary. However, manual cleaning is very time-consuming, labor-intensive and very expensive, since it usually requires the equipment to be disassembled. Another difficulty in processing is especially when there are business interruptions, such as short-term breakdowns or longer downtimes overnight or over the weekend. In these cases, the polyurethane hot melt adhesive remains motionless in the system and hardenings can deposit on surfaces, especially on moving parts or nozzles of the machines. This is particularly critical where the adhesive comes into contact with ambient air. For this reason, there is a need to provide an alternative to expensive manual cleaning. Cleaning pastes have been proposed, but due to the abrasive components contained therein, they severely damage the systems and therefore do not represent a real alternative. EP 0 544 058 discloses a detergent composition which, in addition to a non-isocyanate-reactive polyurethane composition, contains a monofunctional alcohol. Furthermore, US 5,772,790 discloses a detergent composition which, in addition to a non-curable polyurethane prepolymer, contains a monofunctional amine. However, amines are problematic in terms of occupational hygiene and environmental toxicology, since amines have a corrosive effect. The preferred fatty amines in particular are problematic since, in the event of accidental contact, for example in the event of an accident, their tenside character makes them extremely difficult to remove from the eyes, particularly before the caustic effect occurs. Furthermore, working with low molecular weight amines is always associated with an unpleasant odor.

DESCRIPTION OF THE INVENTION It was therefore the object of the present invention to provide an effective detergent composition which overcomes the disadvantages of the prior art and in particular contains no corrosive amines and is advantageous in terms of work hygiene. Surprisingly, it was found that this can be achieved by a detergent composition according to claim 1.

The detergent composition used is free of corrosive components and offers toxicological advantages. The substances used are essentially free of unpleasant smells and well tolerated. By varying the carrier material and the NCO-reactive substance, the properties of the detergent composition can be easily adapted to the hot melt adhesives to be cleaned.

WAYS OF CARRYING OUT THE INVENTION The present invention relates to a detergent composition for reactive polyurethane hotmelt adhesives comprising at least one

Carrier A, which carries no functional groups, which with

Isocyanate are reactive, and at least one compound B, which a

Isocyanate-reactive functional group carries, and a monofunctional amide of formula (I) or formula (II) or a monofunctional imide of formula (IM).

The detergent composition comprises at least one carrier A which does not carry any functional groups which

Isocyanate groups are reactive. Under a "carrier" in the sense of this

Writing is understood to mean polymers which are thermoplastic and which

Compound B can absorb substantially homogeneously. It is important that the carrier A has no isocyanate-reactive groups in order to prevent the carrier A from having a crosslinking action when it comes into contact with the reactive polyurethane hot melt adhesive. A wide variety of materials can be used as the carrier A, but the carrier A must be thermoplastic and must not have any isocyanate-reactive groups. Furthermore, the carrier A should advantageously have a viscosity at the application temperature which is comparable to that of the reactive polyurethane hot-melt adhesive to be displaced. Examples of suitable non-reactive carriers A are non-reactive polyurethanes; natural, chemically modified, synthetic waxes or resins; or blocked polyols or homo- or copolymers. Examples of suitable non-reactive polyurethanes are stoichiometrically blocked polyurethane prepolymers which are inertized with a blocking agent. On the one hand, polyurethane prepolymers containing isocyanate groups can be blocked with blocking agents such as, for example, ε-caprolactam or monofunctional alcohols or amines or mercaptans. On the other hand, polyurethane prepolymers containing OH groups can be blocked by monofunctional isocyanates, in particular p-tosyl isocyanate. In a preferred embodiment, a non-reactive polyurethane is used which consists of the reactive polyurethane hot-melt adhesive to be displaced, the reactive isocyanate groups of which are reacted with a monofunctional alcohol, amine, mercaptan, amide or imide, in particular an amide of the formula (I) or (II) have been blocked. Blocked polyols are in particular essentially totally etherified polyols. The polyol backbone of this etherified polyol is particularly selected from the group comprising polyether polyols, polyester polyols, polycaprolactone polyols. In particular, these are dialkoxypolyalkoxydiols, preferably dimethoxypolyethylene glycols or dimethoxypolypropylene glycols, or alkoxy polyesters polyols. The etherified Polyesteφolyole in particular have neither free hydroxyl groups nor free carboxyl groups. On the other hand, suitable blocked polyols are especially polyesters, polycarbonate polyols, polyhydroxy-terminated polybutadiene polyols, polyether polyols, in particular polyoxyalkylene polyols, which are stoichiometrically blocked with a monofunctional isocyanate compound, so that neither free hydroxyl groups nor free carboxyl groups are present. In the case of the blocked carriers mentioned, care should be taken to ensure that the blocking agent does not unblock to a significant extent at the application temperature of the detergent composition. Also suitable as carrier A are rosin, hydrocarbon resins, hydrogenated or non-hydrogenated terpene resins and petroleum resins. Suitable homopolymers or copolymers are thermoplastic homopolymers or copolymers, in particular those which are prepared from the polymerization of monomers which have C =C double bonds, in particular at least one monomer selected from the group comprising ethylene, propylene, butadiene, vinyl ester, vinyl chloride, Styrene and esters of acrylic or methacrylic acid. Copolymers of ethylene and vinyl ester, in particular ethylene / vinyl acetate copolymers (EVA), are preferred. Ethylene / vinyl acetate copolymers have been shown to be particularly suitable as carriers. Compared to the blocked polyurethane prepolymers, the ethylene / vinyl acetate copolymers are characterized above all by a low price and wide commercial availability. Contrary to the specialist opinion, as expressed, for example, in EP 0 544 058, it was found that EVA is very miscible with polyurethane adhesives and is therefore suitable for use as a carrier material of a detergent composition. The carrier A advantageously has a glass transition temperature (Tg) which is lower than the application temperature of the detergent composition. The carrier A is selected in particular such that the

Polarity of the carrier A to that of the displaced

Hot melt adhesive is matched. Because polyurethane hotmelt adhesives should preferably have a polar character, this means that especially polar carrier A is preferred. Carrier A is a significant quantity of the detergent composition. The proportion is usually more than 50% by weight, in particular between 60 and 90% by weight, based on the detergent composition.

The detergent composition further comprises at least one compound B which carries an isocyanate-reactive functional group. This compound B is either a monofunctional amide of the formula (I) or of the formula (II) or a monofunctional imide of the formula (III).

OO

N (III) IH R ¹ represents an H, a CrC-alkyl radical or a benzyl radical. R ² represents a C ₈ -C ₂₂ alkyl radical which is saturated or unsaturated. R ³ represents a C ₈ -C ₂₂ alkyl radical which is saturated or unsaturated. R ⁴ represents a -C-C ₇ - or a C ₈ -C ₂₂ alkyl radical which is saturated or unsaturated. In particular, R ^{4 is} a saturated C 1 -C ₇ -alkyl radical, in particular methyl, ethyl or propyl. Unsaturated is understood here as meaning “containing carbon-carbon double or triple bonds”. The radicals can also be polyunsaturated, ie there can also be several such double and / or triple bonds in the same radical. If this is the case, these multiple bonds can be conjugated to one another or isolated from one another. The radicals R ¹ , R ² , R ³ or R ⁴ can be branched or unbranched independently of one another. However, the radicals are preferably unbranched. Branching in the immediate vicinity of the amide group are particularly disadvantageous. It is therefore preferred that the carbon which is directly connected to the nitrogen or the carbon atom of the amide group is a hydrogen atom-carrying carbon, in particular a methylene carbon. Branching in the immediate vicinity of the amide group is disadvantageous because this leads to a steric hindrance in the reaction with the isocyanate group and the reactivity of the compound B is thereby reduced. This is particularly pronounced for compounds B of the formula (III). In the case of the compounds (I) and (III), the radicals R ² , R ³ or R ⁴ preferably have an odd number of carbon atoms, while in the case of compounds of the formula (II) R ² preferably has an even number of carbon atoms. R ¹ is preferably a hydrogen atom. The compound B preferably has a melting or softening point between 40 and 120 ° C., in particular between 50 and 100 ° C.

In one embodiment, compound B is an amide of formula (I). Preferred compounds B of formula (I) have an H as

Substituents R ¹ . This class of primary amides are the

Known to those skilled in the art under the term "fatty acid amides". However, not all fatty acid amides are equally suitable. In particular, fatty acids with an alkyl radical of more than 22 carbon atoms are not suitable. Such fatty amides R ² CONH ₂ can be converted, for example, by the reaction of the corresponding fatty acid R ² COOH with ammonia. The compounds B of formula (I), in which R ^{1 represents} a C 1 -C 4 -alkyl radical or a benzyl radical, can be prepared, for example, by N-alkylations of the corresponding fatty amide R ² CONH ₂ using alkyl halogens, or can be obtained from the reaction of a C 1 -C 4 -alkylamine or

Obtained benzylamine with the corresponding fatty acid R ² COOH. Particularly preferred compounds B of the formula (I) are selected from the group comprising lauryl, myristin, palmitin, stearin, arachine, tubercolostaearin palmitolein, oleic, linoleic, linolenic, elaseostearic, eruca arachidonic acid amide ,

In a further embodiment, compound B is an amide of the formula (II). Such amides can be prepared from the reaction of fatty acid amines R ² NH ₂ with the respective carboxylic acid R ¹ COOH or the respective acid chlorides R ¹ COCI. The fatty amines used for this purpose are usually produced by reduction from the corresponding fatty amides or directly from the corresponding fatty acids.

In a further embodiment, compound B is an imide of the formula (III). Such amides can be obtained, for example, from the reaction of a fatty amide R ³ CONH ₂ with an acid chloride R ⁴ COCI or with an acid anhydride (R ⁴ CO) ₂ O. Compounds B are preferably technical mixtures of amides or imides with residues of different lengths R ² , R ³ or R ⁴ , in particular technical mixtures of fatty acid amides. Compounds B of the formula (I) are preferred, in particular

Stearic acid amide or erucamide. The most preferred compound B is erucamide.

It is important for the essence of the invention that the compound B has only one amide or one imide group and has no further isocyanate-reactive groups. Because it is important that the connection B with only one

Isocyanate group of a polymer R- (NCO) _{n of} the reactive hot melt adhesive reacts and crosslinks are prevented. R here means a polymeric chain structure of a reactive polyurethane hot-melt adhesive polymer which carries n isocyanate groups. The reaction of amides of the formula (I) or (II) with isocyanate gives acylureas of the formula (IV) or (V), or results from the reaction of imides of the formula (III) with isocyanates N, N-diacylureas of the formula ( VI).

(i) (IV)

(II) (V) (Holy) (VI)

By choosing the radicals R ¹ , R ² , R ³ and R ⁴ and the one used

The type of compounds B ((I), (II) or (III) or mixtures thereof) can be

Reactivity of the detergent composition can be controlled to a very wide extent and tailored to the needs of the respective cleaning.

The content of reactive compound B in the detergent composition should be selected so that the deactivation of the isocyanate groups of the reactive polyurethane hot-melt adhesive takes place as efficiently as possible. This depends very much on the free isocyanate group content of the hot melt adhesive. It has been shown that a content of 10 to 150 mmol, in particular 40 to 100 mmol, of compound B per 100 g of detergent composition usually represents a good application.

The detergent composition advantageously further comprises a dye or a pigment. This dye or pigment is in particular to be selected such that it can be incorporated as homogeneously as possible into the detergent composition and remains homogeneously distributed in the detergent composition even after prolonged storage and in particular shows no settling or floating. Furthermore, such a dye or pigment should be clearly recognizable when it is mixed with the hot melt adhesive. This is achieved in particular in that the dye has a high molar extinction coefficient at a wavelength at which the hotmelt adhesive does not absorb, or absorbs it only slightly. It is also conceivable that such a dye or pigment becomes colorless or changes its color due to the reaction with isocyanate groups. Dyes are preferably used which are present in solution in carrier A. The advantage of using such a dye or pigment is that it is visually apparent whether cleaning has taken place and there is no reactive polyurethane hot melt adhesive in the system or whether the cleaning agent composition has been completely removed after restarting. This is particularly important because, on the one hand, incomplete displacement of the hot melt adhesive can lead to hardening. On the other hand, curing problems and associated expensive damage can occur if the detergent composition is mixed with the reactive polyurethane hot melt adhesive unnoticed and a. Reactive "polyurethane" hot melt adhesive contaminated with the detergent composition and thus blocked is converted into one intended for the reactive polyurethane hot melt adhesive It is therefore extremely important to ensure that no such mixtures occur after cleaning, or that all cleaning agent compositions can be removed from the system or device to be cleaned as quickly as possible. For this reason, it is also advantageous to that when the detergent composition is expelled, the amount of hot melt adhesive loaded with the detergent composition is as small as possible, so that as little waste is generated as possible, if no dye or pigment is used , the time of complete removal of the detergent composition must be determined using other methods, such as measuring the NCO content. However, such measurements can be very complex and time-consuming.

The detergent composition may further contain fillers if necessary. To damage the systems and equipment too As a rule, these fillers should not be abrasive. Detergent compositions containing no fillers are preferred. The detergent composition can further if necessary

Components contain, such as plasticizers, stabilizers, in particular heat stabilizers, surface-active auxiliaries, such as, for example, surfactants, as are found in conventional cleaning agents. However, there are limits to the use of plasticizers. With high contents or certain types there is the disadvantage that a migration-containing detergent composition becomes greasy on storage due to migration effects and therefore becomes difficult to handle. The optional components of the detergent composition should be selected such that they have no functional groups that do not react with isocyanates, especially at the cleaning temperature. The detergent composition advantageously has a viscosity at the cleaning temperature that is comparable to the hot melt adhesive to be displaced at this temperature. If the detergent composition has a viscosity that is much lower than that of the hot-melt adhesive to be displaced, the cleaning effect is impaired, since the detergent composition only flows past the hot-melt adhesive, according to the path of least resistance, without actually effectively expelling it. For this reason, solvents are very poorly suited as cleaning agents for this purpose. If the detergent composition has a viscosity that is significantly higher than that of the hot-melt adhesive to be displaced, the displacement effect of the detergent composition is very good, but there is the major disadvantage that after the system has been cleaned or the detergent composition of the device is difficult to displace by a subsequent hot melt adhesive. It is therefore advantageous that the viscosities of the detergent composition and the reactive polyurethane hot-melt adhesive to be displaced at the cleaning temperature are comparable, in particular such that the ratio of the viscosity of the detergent composition to the polyurethane hot-melt adhesive at the cleaning temperature is between 1.7 and 0.3, in particular between 1.6 and 0.5, preferably between 1.2 and 0.8. As a result, good and rapid mixing is achieved between the polyurethane hot-melt adhesive and the detergent composition, or with the isocyanate-reactive compound B, so that the reactive polyurethane hot-melt adhesive is completely deactivated as quickly as possible. In practice, the viscosity of the detergent composition is 100 to 100,000 mPas, in particular 20,000 to 20,000 mPas at the application temperature. It is also advantageous for cleaning if the cleaning agent composition is compatible with the reactive polyurethane hot-melt adhesive to be displaced. This compatibility is preferably also given at high temperatures, in particular at the cleaning temperature. In further embodiments, the detergent composition comprises mixtures of carrier A with different melting points or mixtures of detergent compositions whose carrier A have different melting points are used. This allows a modular use by mixing carrier A or detergent composition, the composition of which can be easily adapted to the needs on site if, for example, different reactive polyurethane hot melt adhesives are used on the same system or device. The detergent composition must be stable, at least for the time of cleaning, at temperatures to which it is exposed during cleaning. It is desirable that the detergent composition can remain at cleaning temperatures for at least a few hours, in particular days, without the detergent composition being substantially decomposed or broken down.

The detergent composition is advantageously as free from water or moisture as possible. For this reason, raw materials that are as dry or dried as possible should be used in the production process and no water-absorbing ingredients should be used.

In a preferred embodiment, the detergent composition comprises an ethylene / vinyl acetate copolymer as carrier A and a fatty acid amide of the formula (I) as compound B. In a particularly preferred embodiment, the detergent composition comprises or consists of an ethylene / vinyl acetate copolymer as carrier A and a fatty acid amide of formula (I) as compound B and a dye. Such a detergent composition is extremely efficient, inexpensive and extremely advantageous in terms of ecology and occupational hygiene.

The detergent composition is usually made as follows. The carrier A is slowly heated with stirring to a temperature which is above the melting point of the carrier. The compound B is then added with stirring or dispersing. Depending on the dosage form of this compound B, it is used for this purpose as granules, powder or as a melt. The other components can then be added. If stabilizers are used, it is advantageous to add them as early as possible in the manufacturing process. If a blocked polyurethane prepolymer is used as carrier A, its preparation is advantageously carried out in situ at the beginning of the detergent composition. At the end of production, the detergent composition is brought into the correct dosage form as required for the application. It can be present, for example, as granules, in the form of scales or as a block. This transfer to the dosage form is carried out in a known manner and can be carried out directly from the melt or during or after cooling. The detergent composition is advantageously converted from the melt into the use form immediately after production. When selecting this dosage form, it is advantageous to choose a form which enables the detergent composition to be dosed even after a long storage period. It is also important to ensure that the packaging used for the detergent composition offers adequate protection and should in particular be impermeable to moisture. The addition to the system to be cleaned or the device to be cleaned should be in solid form or in the form of a melt. It is preferred if the detergent composition is in the form of granules or flakes. The cleaning temperature is usually the processing temperature of the reactive polyurethane hot melt adhesive, typically 70 to 180 ° C, in particular 90 to 150 ° C. However, it can be advantageous to carry out the cleaning at a higher temperature so that the reactive polyurethane hot-melt adhesive to be displaced becomes less viscous. However, due to the decomposition temperature of the polyurethane hot melt adhesive or the detergent composition, there are system-related upper limits that must not be exceeded under any circumstances.

A system or device is typically cleaned as follows. The supply of reactive polyurethane hot melt adhesive is interrupted and the detergent composition is added to the system or the device. After the detergent composition is in the form of a melt, the delivery of the polyurethane hot-melt adhesive is continued, and the expelled one Amount of polyurethane hot melt adhesive collected until it is ensured that there is no reactive polyurethane hot melt adhesive in the system or device. The rate at which polyurethane hot melt adhesive is expelled, and therefore the time at which the detergent composition comes into contact with the reactive polyurethane hot melt adhesive, depends on many factors, in particular the cleaning temperature, the reactivity of compound B , the content of free isocyanate groups of the reactive polyurethane hot-melt adhesive, the dimensions and geometry of the system or device to be cleaned and the concentration of compound B in the detergent composition. When the system or the device is re-loaded with reactive polyurethane hot melt adhesive, the ejected material is collected until it is ensured that the entire detergent composition has been removed from the system or the device. All of the collected polyurethane hot melt adhesive is to be disposed of or used for some other purpose.

The detergent composition is particularly suitable for cleaning processing plants and application equipment, especially application equipment, and reactive polyurethane hot melt adhesives. Typically, these systems and devices have constricting parts such as slots or nozzles, moving parts such as screws, rollers, stirrers, blades, pumps or even hoses and pipes, which can only be cleaned manually with a great deal of work and expense. With the detergent composition according to the invention, a thorough, yet gentle and quick cleaning of these systems and devices can be carried out by removing the reactive adhesive from them. It is important that the mixture of the reactive polyurethane hot melt adhesive with the detergent composition is not distinctive

Has increased viscosity, both when mixing and after

Response because this is for both cleaning and restarting the

Investment is of great importance. It goes without saying that such cleaning agent compositions can also be used for cleaning systems in which reactive polyurethane hotmelt adhesives are produced. In a further aspect, the invention relates to a method for

Cleaning a manufacturing or application system or an application device from reactive polyurethane hot melt adhesive. Here, a reactive polyurethane hot melt adhesive with a detergent composition described is displaced from an application system or an application device.

Another aspect relates to the use of a detergent composition described for removing reactive polyurethane hotmelt adhesives from an application system or an application device, in particular from an application apparatus.

Another aspect relates to the process for the preparation of a detergent composition, in particular one in which the carrier A is heated above the melting point of the carrier and then the compound B with stirring or

Dispersing is added.

Examples The examples serve to illustrate the invention and are in no way to be interpreted as limiting the invention. Production of detergent compositions:

Table 1 Raw materials used.

In a closed vessel, the carrier A, compound B and the pigment from Table 1 are initially introduced in the amounts according to Table 2 and melted at 140 ° C. After the raw materials have melted, they are stirred under vacuum for 30 minutes. After mixing, there is a homogeneous, blue melt which solidifies when cooled to room temperature.

Table 2. Detergent compositions Properties of detergent compositions The detergent compositions are well suited as detergents, as Table 3 and Table 4 illustrate.

Methods of determination The viscosity of the detergent composition was determined at 130 ° C according to Brookfield Thermosel (based on DIN EN ISO 3219). The softening point was determined using DIN 52011 (ring & ball).

For storage, the detergent composition was stored in a closed vessel for 16 or 24 hours at 140 ° C. and then visually examined whether color changes or separations were present.

The compatibility of the detergent composition with a reactive polyurethane hot melt adhesive was determined using SikaMelt® 9600 (commercially available from Sika Schweiz AG) in a mixture of 12 g detergent composition and 9 g hot melt adhesive. For this purpose, the hot melt adhesive and the detergent composition were stirred for 1 hour at 140 ° C. in a closed vessel and then assessed visually for any separations or color changes. At the same time, the reaction with the NCO groups was checked by IR as follows.

The implementation of the detergent composition with a reactive polyurethane hot melt adhesive was done using SikaMelt® 9600

(commercially available from Sika Schweiz AG). For this, the

Detergent composition the melted adhesive in the

Ratio 12g detergent composition: 9g adhesive (w / w) added and stirred in a closed vessel under vacuum at 130 ° C for 1 hour. The viscosity and the course of the reaction were assessed. The course of the reaction was determined by determining the intensity of the NCO band (2270 cm ^'1 ) in the infrared spectrum by diluting the reaction mixture (0.1g) with THF (10 ml) (Nicolet 320 FTIR, 700 - 4000 crτϊ ¹ , ATR) ,

The reaction mixture was filled into aluminum tubes of 30-40 g each and stored in a warm air oven at the appropriate temperature.

The values from Tables 3 and 4 show that the detergent compositions are stable and have no negative effects on the hot melt adhesive. In particular, there is no increase in viscosity after storage with the hot melt adhesive.

Table 4. Properties of detergent composition R3

Cleaning a tank melting plant A tank melting plant type SKA-04 PU (Steinmeyer Klebtechnik, D-Bad Camberg) with a modified tank (150 mm diameter instead of 130 mm diameter) with a content of 4 liters was used. It was connected to an outlet nozzle via a 2.5 m long hose with a diameter of 8-10 mm. Furthermore, this tank melting system has a gear pump for delivery. The tank melting plant was filled with the reactive polyurethane hot melt adhesive SikaMelt® 9630 (commercially available from Sika Schweiz AG). The adhesive was first conveyed out of the system to the minimum fill level. Then R3 was added at 130 ° C as an example of a detergent composition. The cleaning was then carried out by conveying the cleaner through the system. The reactive hot melt adhesive was removed and neutralized at the same time. The cleaning was monitored on the one hand visually and on the other hand by tracking using ATR-IR. Figure 1 shows the course of cleaning. On the one hand, the ratio of the transmission of the pure hot melt adhesive SikaMelt® 9630 To to the transmission of the sample Tm compared to the flushing mass m expelled from the system in kilograms was recorded by means of ATR-IR at a wave number of 2270 cm ^"1 and its color was assessed visually. At the beginning ( Area i) the color of the ejected adhesive is slightly pale yellow, corresponding to the natural color of the polyurethane hot melt adhesive. At about 0.8 kg the first traces of blue color are visible. From about 1.4 kg the color is constantly deep blue (area in). In between is a constantly stronger one 1 shows clearly that the detergent composition is very well suited as a detergent for reactive polyurethane hot-melt adhesives and that the cleaning is very efficient. On the other hand, the color determined correlates with this the Isocy anatgehalt. In an analogous manner, it could be shown that after adding new SikaMelt® 9630 to the tank melting plant and then squeezing it out, the detergent composition R3 could be displaced with comparable efficiency by not being able to determine any residues of the detergent composition that could be determined visually (no blue color) or by IR ,

Thermal stability compared

Table 5. Blocking agents used The NCO groups of the reactive hot-melt adhesive with an NCO content of% NCO _{κ were} reacted stoichiometrically with erucamide, stearyl alcohol or octadecylamine by using these substances in a Amount m _x each of an amount m _κ SikaMelt® 9670 (commercially available from Sika Schweiz AG) {% NCO _κ = 2.1) were added using the following formula: MG _X m _κ x% NCO _κ m -x— - ^x 42 100 Die It was added at 130 ° C. After stirring in a closed vessel for one hour under vacuum at 130 ° C., the reaction mixture was each filled into aluminum tubes of 30-40 g each, the viscosity of this reaction mixture measured (η _x ). The tubes were then stored in a warm air oven at the appropriate temperature and the viscosity measured after the respective time.

ATR-IR measurement showed that there was a complete reaction with the NCO groups.

*> 250O00 mPa ^* s Table 6 shows that an adhesive that has been blocked with the amide R6 is stable for a long time at 120 ° C and only shows a slight increase in viscosity after a very long period of storage at this temperature, while with the amine C1 it is already immediate after mixing there is an extremely strong increase in viscosity. With alcohol C2, however, there is a sharp decrease in viscosity. Such a reduction in viscosity is undesirable, however, since such a sharp reduction in the viscosity is very disadvantageous for cleaning or for the displacement of the blocked hot melt adhesive by fresh reactive hot melt adhesive.

Claims

claims

1. Detergent composition for reactive polyurethane hot-melt adhesives comprising at least one carrier A which does not carry any functional groups which are reactive with isocyanate; and at least one compound B which carries an isocyanate-reactive functional group and is a monofunctional amide of the formula (I) or of the formula (II) or a monofunctional imide of the formula (III),

where R ^{1 is} H, a C ¹ -C ₄ -alkyl radical or a benzyl radical, R ^{2 is} a C ₈ -C ₂₂ saturated or unsaturated alkyl radical, R ^{3 is} a C ₈ -C ₂₂ saturated or unsaturated alkyl radical, R ⁴ represents a C ₁ -C ₇ - or C ₈ -C ₂₂ saturated or unsaturated alkyl radical.

Detergent composition according to claim 1, characterized in that the carrier A is a blocked polyurethane pre- polymer, a hydrocarbon resin, a blocked polyester, a blocked polyol or a copolymer of at least the monomers selected from the group comprising ethylene, propylene, butadiene, vinyl ester, vinyl chloride, styrene and esters of acrylic or methacrylic acid.

3. Detergent composition according to claim 2, characterized in that the carrier A is a blocked polyurethane.

4. Detergent composition according to claim 2, characterized in that the carrier A is an ethylene-vinyl acetate copolymer.

5. Detergent composition according to one of the preceding claims, characterized in that the compound B has the formula (I).

6. detergent composition according to any one of the preceding claims, characterized in that in connection BR ² and R ³ an unsaturated C ₈ -C ₂ o-alkyl radical, in particular a CnH ₂ n-ι or C _n H _2n -3 or C _n H _2n - ₅ with n = 8-20, preferably an olefinically unsaturated alkyl radical.

7. detergent composition according to any one of the preceding claims, characterized in that in connection BR ² and R ^{3 is} a C ₈ -C ₂₂ alkyl radical, in particular a Ci ₅ -C ₂₂ alkyl radical.

8. detergent composition according to any one of the preceding claims, characterized in that in compound BR ^{4 is} a C1-C7 alkyl radical, in particular methyl, ethyl or propyl.

9. detergent composition according to any one of claims 1- 7, characterized in that in combination BR ¹ = H and R ³ = R ⁴ .

10. Detergent composition according to one of the preceding claims, characterized in that the detergent composition has approximately the same viscosity as that of the reactive polyurethane hot-melt adhesive to be cleaned at the cleaning temperature.

11. Detergent composition according to one of the preceding claims, characterized in that the detergent composition additionally contains at least one dye or a color pigment.

12. Detergent composition according to one of the preceding claims, characterized in that the detergent composition contains 10 to 150 mmol, in particular 40 to 100 mmol, of compound B per 100 g of detergent composition.

13. A method for producing a detergent composition according to any one of claims 1 to 12, characterized in that the carrier A is heated above the melting point of the carrier and the compound B is then added with stirring or dispersing.

14. A method for cleaning a manufacturing or application system or an application device from reactive polyurethane hot melt adhesive, characterized in that a reactive polyurethane hot melt adhesive is displaced from an application system or an application device with a detergent composition according to one of claims 1 to 12.

15. Use of a cleaning agent composition according to one of claims 1 to 12 for removing reactive polyurethane hotmelt adhesives from an application system or an application device, in particular from an application apparatus.