EP0791048B1 - Process for producing washing and cleaning agent tablets by means of microwave and hot-air treatment - Google Patents

Abstract

PCT No. PCT/EP95/04242 Sec. 371 Date May 7, 1997 Sec. 102(e) Date May 7, 1997 PCT Filed Oct. 30, 1995 PCT Pub. No. WO96/14391 PCT Pub. Date May 17, 1996A process for producing detergent tablets by exposing a detergent composition to microwave radiation in the frequency range from 3 to 300,000 MHz while treating the detergent composition with hot air having a temperature of 50 DEG C. to 300 DEG C.

Description

The invention relates to a method for producing detergent tablets using microwave technology and one Hot air treatment.

The disadvantage of conventional detergent tablets that are usually produced by pressing or melting together, is that these tablets are not compact because of their compactness dissolve quickly enough and the active substances are released too slowly. In addition, such tablets have too slow a disintegration rate.

The older, unpublished international application PCT / EP94 / 01330 (WO-A-94/25563), to the disclosure of which reference is expressly made detailed the production of washing and cleaning active tablets using microwave technology, which has an extremely high dissolving speed or decay rate with simultaneous breaking strength exhibit. An essential requirement for the production of tablets made from powdered or granular raw materials using of microwaves consists in the fact that at least some of these starting materials is in a hydrated form, with "hydrated" "hydrates under certain conditions regarding temperature, pressure or relative humidity of the atmosphere to which the raw material is exposed or with which the raw material is in equilibrium " becomes. The term "hydrated" is also defined in PCT / EP94 / 01330, i.a. hydrated raw materials are those that contain bound water of crystallization contain or which are able to add water added from the outside bind at least partially as water of crystallization or such substances, that do not form defined hydrates, but are able to form water tie, e.g. Alkali hydroxides.

In the context of this invention, “microwaves” is understood to mean the entire frequency range between 3 and 300,000 MHz, which thus also includes the radio wave range of 3 to 300 MHz in addition to the actual microwave range of above 300 MHz. With the help of this technique, so-called macrosolids can be produced, which, in addition to tablets, also include blocks. The premixes are connected to one another at the contact points by local melting / sintering caused by the microwave beams. The voids that exist between the individual premix components prior to irradiation with microwaves result in a high porosity of the resulting tablet and thus contribute to improving the dissolving properties of the tablet.
In order for local sintering of the premix components to be possible, at least some of them must have sintering properties on the surface. For this it is necessary that the premix components themselves or their surface contain enough water so that heating of this water causes the contact points on the premix components to fuse. According to the teaching of the international patent application PCT / EP94 / 01330, at least part of the mixture to be irradiated with microwaves must be in a hydrated form.

In the context of the present invention, the term "tablets" is therefore not limited to a specific spatial shape; in principle, every conceivable three-dimensional shape possible, depending on which outer shape the powder or granular premixes, e.g. through the container used is imposed.

The chemical composition of the i.a. powder or granular premixes - and thus also the tablets - can be used over a very wide range be varied, here is explicitly based on the revelation in PCT / EP94 / 01330 referenced.

In US 4,584,281 (Clorox Company) solid water-soluble foaming agents produced by heating strongly water-containing silica / silicate gels. being the Evaporation of the amount of water swells the gel into a foam, which is then in special shapes can harden. The energy supply step in this process can be done for example by microwave energy.

It has now been shown that tablets by microwave radiation of powdery or granular premixes on the one hand - if the radiation is too short - for storage and transport lack the necessary breaking strength, on the other hand - if it is too long Irradiation - Charring in the tablet core. So far there has been a solution this problem is not always possible because it is often sufficient Breaking strength was automatically associated with charring inside the tablet and avoiding charring too little breaking strength entailed.

The object of the present invention is therefore to find a method at the above Disadvantages do not occur, i.e. with the tablets received that have a high breaking strength and at the same time none Charring.

The object is achieved in that with during the irradiation process Microwaves a treatment of the premix with hot air at a temperature from 50 ° C to 300 ° C, preferably 100 ° C to 250 ° C, especially 150 ° C to 220 ° C.

Under "premix" the powder and / or granular mixture is made understand the individual detergent or cleaning agent components. As In principle, individual components are all substances that are customary for the production of solid washing or cleaning agents for Textiles and hard surfaces can be used. In particular, in In this connection, reference is made to the substances disclosed in PCT / EP94 / 01330.

Suitable framework substances are, for example, amorphous silicates such as metasilicates or water glasses, phosphates, alkali carbonates, alkali sulfates, zeolites, but also organic components such as water-containing citrates, for example sodium citrate dihydrate, or water-containing acetates, for example sodium acetate trihydrate. Suitable substitutes or partial substitutes for phosphates and zeolites are crystalline, layered sodium silicates of the general formula NaMSi _x O _{2x + 1} .yH ₂ O, where M is sodium or hydrogen, x is a number from 1.9 to 4 and y is a number from 0 to 20 and preferred values for x are 2, 3 or 4. Such crystalline layered silicates are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layered silicates are those in which M is sodium and x is 2 or 3. In particular, both β and γ-sodium disilicates Na ₂ Si ₂ O ₅ .yH ₂ O are preferred.

Useful organic builder substances are preferred, for example polycarboxylic acids used in the form of their sodium salts, such as citric acid, Adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids, Aminocarboxylic acids, nitrilotriacetic acid (NTA), provided such use is not objectionable for ecological reasons, as well as mixtures from these. Preferred salts are the salts of polycarboxylic acids such as citric acid, Adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures of these.

Suitable polymeric polycarboxylates are, for example, the sodium salts polyacrylic acid or polymethacrylic acid, for example those with a relative molecular weight of 800 to 150,000 (based on acid). Suitable copolymeric polycarboxylates are, in particular, those of acrylic acid with methacrylic acid and acrylic acid or methacrylic acid with maleic acid. Copolymers of acrylic acid with maleic acid have proven particularly suitable proven that 50 to 90 wt .-% acrylic acid and 50 to 10 wt .-% maleic acid contain. Their relative molecular mass, based on free acids, is generally 5,000 to 200,000, preferably 10,000 to 120,000 and in particular 50,000 to 100,000. Organic are also particularly preferred Degradable terpolymers, for example those which are salts of the monomers Acrylic acid and maleic acid as well as vinyl alcohol or vinyl alcohol derivatives (P 43 00 772.4) or the monomers as salts of acrylic acid and Contain 2-alkylallylsulfonic acid and sugar derivatives (DE 42 21 381).

Other suitable builder systems are oxidation products of carboxyl-containing ones Polyglucosans and / or their water-soluble salts as they described for example in the international patent application WO-A-93/08251 be or their production, for example, in the international Patent application WO-A-93/16110 is described.

Also known are the other preferred builder substances To name polyaspartic acids or their salts and derivatives.

Other suitable builder substances are polyacetals, which by reaction of dialdehydes with polyol carboxylic acids, which have 5 to 7 carbon atoms and have at least 3 hydroxyl groups, for example as in European Patent application EP-A-0 280 223 can be obtained. Preferred polyacetals are derived from dialdehydes such as glyoxal, glutaraldehyde, Terephthalaldehyde and mixtures thereof and from polyol carboxylic acids such as gluconic acid and / or glucoheptonic acid.

The inorganic and / or organic builder substances are preferred in amounts of about 10 to 60% by weight, in particular from 15 to 50 % By weight, used in the tablets.

Solid acids are used to manufacture acidic detergent tablets such as. Amidosulfonic acid or phosphonic acids are used.

Furthermore, i.a. anionic, cationic, amphoteric or zwitterionic, but above all contain non-ionic surfactants as described in PCT / EP94 / 01330 are disclosed; nonionic surfactants such as e.g. Fatty alcohol ethoxylates. In addition, bleach may be used based on oxygen or chlorine, disinfectants e.g. B. quaternary ammonium compounds, foam inhibitors, enzymes, fillers etc. included.

The duration of the irradiation process is usually between 15 seconds and 90 minutes, preferably between 1 minute and 30 minutes, in particular between 1 minute and 5 minutes.

Another possibility according to the invention is to take the tablets only after Treat the irradiation process with hot air. Between radiation and In principle, hot air treatment can take any length of time, usually however at most 24 hours, preferably at most 60 minutes, especially at most 2 minutes. The duration of the hot air treatment can in principle as long as the tablet does not damage the hot air treatment survives; for economic reasons it is up to 30 minutes, preferably up to 10 minutes, especially up to 3 minutes.

A method is particularly preferred in which the treatment with hot air takes place both during the irradiation process and after the irradiation. Here, too, there is usually at most 24 hours, preferably at most 60 minutes, in particular at most 2 minutes, between irradiation and subsequent hot air treatment.
The duration of the hot air treatment is usually in the period already mentioned above.

The hot air is generally by a conventional hot air blower with adjustable Air temperature generated.

The microwave radiation can be carried out, for example, in a microwave oven as described in PCT / EP94 / 01330; the products irradiated in this way can then be subjected to hot air treatment. It is also possible to carry out microwave radiation and hot air treatment in the furnace at the same time.
The microwave radiation and / or hot air treatment can accordingly - as described - be carried out in batches in a device, for example an oven.

The microwave irradiation (with simultaneous or subsequent or both simultaneous and subsequent hot air treatment) is preferably carried out in a continuous manner.
A system is particularly suitable for this purpose in which the premixes to be irradiated are transported on a conveyor belt through a zone irradiated with microwaves. In addition, hot air is either blown directly into the irradiated zone or into a zone which immediately adjoins the irradiated zone or both into the irradiated zone and into the adjoining zone.

Examples

60 g of powdery premixes (corresponding to the recipes 1 and 2 below) were brought into the desired shape by manual pre-compression or by pre-compression with a pneumatic press at a pressure of 1 to 400 N / cm ² and then optionally removed from the container. "Manual pre-compression" means that the premix filled into an open-topped container is manually compressed from above with a stamp. The pressure in manual pre-pressing is approx. 1 to 20 N / cm ² ; when pressing with the pneumatic press it is approx. 200 to 400 N / cm ² . [The manually pre-compressed premixes were generally more soluble after the irradiation and hot air treatment according to the invention.] Then the moldings were placed on a conveyor belt and transported through a zone irradiated with microwaves, with no hot air treatment being carried out. Working conditions: Assembly line speed 47 cm per minute Length of the irradiated zone 210 cm Microwave source 18 microwave emitters, each with a power of 1200 watts, wavelength 2450 - 2470 MHz Distance from microwave source to assembly line 9 spotlights at 11 cm distance
9 spotlights at a distance of 4 cm

These conditions are defined as "standard conditions". Recipe 1 Amidosulfonic sulfonic acid 96% by weight Octanephosphonic acid 1% by weight C _12-18 fatty alcohol ethoxylate 1% by weight Na ₂ SO ₄ 1% by weight H ₂ O 1% by weight Recipe 2 Pentasodium triphosphate 40% by weight Sodium metasilicate 40% by weight Sodium metasilicate pentahydrate 10% by weight Sodium carbonate decahydrate 5% by weight Dimethyldioctylammonium chloride 3% by weight C _12-18 fatty alcohol ethoxylate 2% by weight

To increase the productivity of assembly line production, both Assembly line speed as well as microwave power compared to the standard conditions doubled; however, the tablets thus obtained had one insufficient breaking strength. A decrease in assembly line speed however, resulted in charring inside the tablets.

Were the - with double assembly line speed and double microwave power manufactured - non-break-resistant tablets after the radiation process for a duration of 2 min. 45 sec of a hot air treatment (200 ° C), then unbreakable tablets were obtained without signs of charring.

When the conveyor belt speed and the microwave power are doubled again a hot air aftertreatment of 7 min. 20 sec was necessary, to get unbreakable tablets.

Claims (5)

1. A process for the production of detergent tablets by exposing a compound containing at least one at least partly hydrated component to microwave radiation in the frequency range from 3 to 300,000 MHz, characterized in that, during their exposure to microwave radiation, the tablets are treated with hot air having a temperature of 50°C to 300°C, preferably 100°C to 250°C and, more preferably, 150°C to 200°C.
2. A process for the production of detergent tablets by exposing a compound to microwave radiation, characterized in that, at most 24 hours, preferably at most 60 minutes and, more preferably, at most 2 minutes after their exposure to microwave radiation, the tablets are aftertreated for up to 30 minutes, preferably for up to 10 minutes and, more preferably, for up to 3 minutes with hot air having a temperature of 50°C to 300°C, preferably 100°C to 250°C and, more preferably, 150°C to 220°C.
3. A process for the production of detergent tablets by exposure to microwave radiation, characterized in that the tablets are subjected both to a simultaneous treatment with hot air according to claim 1 and to an aftertreatment with hot air according to claim 2.
4. A process as claimed in claim 1, 2 or 3, characterized in that the microwave treatment accompanied and/or followed by treatment with hot air is carried out in batches.
5. A process as claimed in claim 1, 2 or 3, characterized in that the microwave treatment accompanied and/or followed treatment with hot air is carried out continuously.