AU606486B2 - Method of casting soap or non-soap detergent - Google Patents

Description

%APPUCAT10N ACCF-PTED AM,-D AMENDMENTS D

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION Form

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: 606486 Application Numberi Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: anmendmcitts made Under Stction 49 and is corrcct for printing.

Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant:

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UNILEVER PLC UNILEVER HOUSE

BLACKFRIARS

LONDON EC4

ENGLAND

Actual Inventor: Address for Serv'ice: GRIFFITH HACK Co., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

Complete Specification for the invention entitled: AS!T m, The foll~owing statement is a full deicption of this invention including the best method of performing it known to mne.m~u ii Ni j

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00 0 a 0 pa 0 a The prese't invention relates to a method of casting a material tu X6ap,.non-soap detergent or mixture thereof, in a liquid or semi-liquid state into a pack.

US 3149188 describes a method of casting soap into a pre-formed mould which is designed to serve as a package or container for the ready-to-use cake and subjecting the liquid mass in the mould to cooling whereby the mass LI0 solidifies into a cake having the contour of the mould. The a mould is airtightly sealed after casting. The moulds are a preferably rigid or semi-rigid bodies whose shape determines the shape of the cake of soap. The mould can be plastic and can have flexible wall portions whose depression will 15 facilitate the removal of the ready-to-use cake from the *0 mould. The method is applicable to transparent soap and thus obviates the traditional open cast method of casting transparent soap into blocks and cutting the blocks into bars and overcomes the shrinkage, loss of perfume and surface deterioration problems associated with open cast bars.

Rather similarly, FR 910256 describes a method of casting liquid soap into a pre-formed mould which is retained as an envelope around the soap and thus delivered to the consumer. The mould should be sufficiently rigid to retain its shape when empty.

According to the present invention there is h'c a r r 4 ooao 00 00o000 a 0 o o.

0 0 4 0 00 0 0000 0 00 o 0 provided a method of casting a material comprising soap, a non-soap detergent or a mixture thereof into solid bar form, the method comprising: filling the material in a liquid or semi-liquid state and at an elevated temperature into a pack made at least substantially of flexible film, airtightly sealing the pack while the material is still 10 liquid or semi-liquid, allowing the material to cool and set to a substantially solid bar, and retaining the bar of set material in the pack as an airtight storage means, wherein the distance between the sides of the pack narrows adjacent both ends of the pack whereby the corners of the solid bar formed in the pack are shaped by the narrowing between said sides of the pack, and/or the flexible film is heat-extensible or heat-shrinkable so as to deform while the material therein is still liquid or semi- 20 liquid, thereby to shape the solid bar formed in the pack.

0000 a ooa oool, ,0o 0 0) 0 a i o aoel tt t 10 0 0 00t 0 e0 The present invention thus provides a method of casting and simultaneously packing a material such as soap (but possibly comprising non-soap detergent as mentioned above).

Use of flexible film can be economical with regard to the initial cost of the pack material. The method can be carried out on a continuous basis. Moreover, a supply of empty packs can be stored in a flat or rolled form, or a Ue I7 2a supply of flexible film for making packs zan be stored and converted into packs only immediately pr~ior t usci. If desired forced cooling can be employed whilst the material is being allowed to set.

The present method can be carried out on a high speed packaging machin analogous to a conventional machine for forming and filling sachets. The method can thus not only be performed at high speeds, but also obviates the need to form and store rigid three-dimensional packs prior to use.

10 Moreover, the invention enables a molten mixture to be made directly into a bar of the like having rounded corners and 0 oo edges and of a pleasing shape. Thus unlike conventional 000 o. casting of soap mixture into large slabs followed by cutting into blocks with prominent edges which require time consuming die stamping, the present method can readily and

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000 9000 V 1 4*000t 0 0 S (e s Ici /y u LL. 1-- 'C speedily produce suitably shaped bars or the like.

The present method can allow the sIhape of the pack to be controlled by contact with the exterior ofC the pack during the setting of the material. Thus for example a filled and sealed pack made substantially from f~texible film could, for example, be lightly moulded in a die and/or have a motif impressed on it. A filled and sealed pack could be pressed between two surfaces in order to produce a bar or tablet-like shape. The surfaces could be flat or one or 0060- both of them could be, for example, concave so as to produce 0 a substantially "cushion" shaped bar. The control need only 0 00 000000 be exerted for as long as necessary for the material to 00000assume a permanent shape. Pressures in the range 0.1 to 00 0 0 0 0 0 0.3,kgf/cm 2 are preferred, the actual pressure selected depending on the properties of the paclt in each case.

o 00 000 0 in order to give an attractive appearance, it is 0 0 0 000 very desirable that the pack should be a skin-tight wrinkle- 00 free fit over the cast material within. To accomplish this, 0 a 00D 0 4 it can be beneficial to shape the pack by distending it with oo oo2O internal pressure, which can be done in various ways.

#010 Pressing the exterior of a filled and sealed pack between two surfaces to control its shape will tend to reduce the volume to surface ratio and so pressurize the incompressible material within the pack. The internal pressure then distends and tensions the film material.

Vhe~ackmay be of a heat--axtendible material, i.e. a material which can stretch permanently when sufficiently hot. If stretching occurs at the tem~perature of the material filled into the pack, the pack will stretch and adjust its shape under the hydrostatic pressure of the hot material in the pack and/or pressure in that material arising from pressure on the pack exterior. Stretching of flat film to adjust its shape to that of the filling of the pack will of course mean that the film is no longer flat.

Another possibilitykis to use a heat-shrinkable flexible film. As this shrinks onto the material in the pack it will pressurize this material which will accordingly o6310 stretch the shrinking film taut.

0 0 oo00 Yet another possibility is that the pack could be o 0 0 00 00000 at least partially shaped prior to filling. This could be 0 00 .oo. carried out by blowing, e.g. into a mould, which is a o0 0 0 00 o, further instance of shaping the pack by distending it with internal pressure, and again stretching the film. The film 0 0 0 0 0 S°00 will remain flexible, but the shaping of it will influence 0 00 S00 the shape which the pack takes when filled.

o0 o: In order to achieve a skin-tight fit the material 0 0. 0a preferably occupies substantially the whole internal volume 20 of the pack on being airtightly sealed. Contact between the 4 material and air can thus be excluded which could be of importance in achieving a long shelf life. such an arrangement can also ensure that when the material is unpacked immediately prior to use, due to the close contact between the material and the pack, the material is presented to the consumer having an unblemished and even surface appearance.

The flexible film is preferably made of

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ii r thermoplastic material. The pack suitably comprises two layers of its constituent film in the form of a bag or sachet having an open end into which to fill the material.

In its unused .e the pack material either preformed into sachets or as separate sheets of film can therefore be stored flat or for example in rolls as supplied from the manufacturers.

The two layers of film can, for example, be formed into a bag or sachet by sealing them together along one or more seams so as to define the flat (unfilled) shape of the 00 C pack while leaving an unsealed portion as the filling 0 00 .00o." opening. The seal could extend around the total periphery 0 00 o.oo of the pack or alternatively the pack could be derived from 00 0 a tube of flexible film material having a transverse seal at one end and being open at tha other end so as to allow the 0 0o °0.0 pack to be filled. For a thermoplastic material the seal 0 00 0 can conveniently be performed by heat welding. Any "skirt" D0 of the film material projecting outwardly from the seam(s) 0 06 can be trimmed away from the set product. Alternatively a "skirt" of film may be avoided by employing knife-edge S welding methods.

It is preferred that a film material is employed which allows the pack when filled to be airtightly sealed by heat welding through a slight excess of soap or the like at the opening to the pack. This can ensure that the material occupies the whole int(rnal .rolume of the pack, and ensures exclusion of any air from the pack.

Preferably the pack is formed immediately prior to I filling with both operations carried out on the same machine. Where the pack is formed from two layers of its constituent film, the pack can be filled with the material and airtightly sealed, with the sealing step conveniently forming at the same time at least a portion of the seam of the next pack to be filled. The present process can thus readily lend itself to operation on a continuous basis. For example a four side sealed sachet/vertical fill process could be employed.

AO The flexible film can readily be removed from the 04 0 09 O bar or the like immediately prior to use by a peeling 0 o 0 action. If desired a tear strip(s) or the like can be 0 oo 0 ooo included integral with the flexible film or attached for S o o example glued to the flexible film in order to help initiate removal of the film from the bar. Alternatively the film 0 0 o can be made of a water-soluble material which dissolves 0 00 .o 0 0 during the first use of the bar or the like.

o The actual film selected in any one case will 0 "a.O depend on the circumstances of each case. Conveniently the S..20 film will be selected such that it can be heat-sealed. A o a t 0 variety of heat-sealing methods are available and generally involve melting the film layers in contact. The available methods include radio frequency or dielectric, bar, band, impulse, hot wire or knife and ultrasonic welding. As mentioned above, the film may have properties such that it can extend and/or shrink around the material being packed so as to provide a skin-tight and wrinkle-free fit at the temperatures encountered on contact with the liquids or L _ii: i 1

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7 semi-liquid material and/or during the time that the material is setting.

Suitable flexible film materials are commercially available. Examples include polyvinylchloride, polyvinylalcohol, polyethylene, Nylon (trade name for polyamide), Surlyn (trade name for ethylene methacrylate copolymer) -e4 polyethyleneterephthalate mixtures thereof.

The thickness of the film selected may depend inter alia on the degree of adjustment, if any, required in the film in o~~O"0 order to provide a skin-tight and wrinkle-free fit. For 00 0 ooo0o polyvinylchloride film for example the preferred thickness a 0 range is from 20 to 60pm, with a more preferred thickness 0 00 0oo being from 30 to o a 00 0 If desired laminated, co-extruded or other multilayer films can be employed. For example a multilayer 0 00 0 oo film could be employed which is designed to combine the good 00 00 0 °0 heat-sealing characteristics of one polymer with the 0 0 0 barrier/high melting point or other useful characteristics 0O°"0 for example ease of printing of another. The film could for o .20 instance be printed with a motif, the product's name or i advertising. In some applications it may be preferable to employ transparent film so that the cast soap bar or the like can be readily viewed.

The present method can be applicable to any castable soap, non-soap detergent or mixture thereof. The soap and/or non-soap detergent being packed can of course include any additional materials conventionally found in toilet or laundry bars. In particular, however, the method L r 8 obviates the problems encountered in traditional pressing techniques as well as those itemised in US 3149188 having regard to transparent bars. The method can thus be especially applicable to transparent, translucent and low fatty matter soap bars.

It is to be understood that the present invention extends to bars, tablets, cakes, blocks or the like of soap, non-soap detergent or mixtures thereof airtightly sealed in a pack according to the present method.

0 Embodiments of the present invention will now be 00 0 oeooot described by way of example only and with reference to the accompanying drawings in which: 0 00 o00' Fig. 1 shows a pack formed by heat-sealing two 00 0 sheets of flexible film; Figs. 2a, 2b, 2c and 2d are side views of the pack 0O S000 seen in the direction of arrow II of Fig. 1 showing o q *O 0 progressive stages from filling to finished product; o o Fig. 3 diagrammatically illustrates the forming and filling of packs on a vertical forming and filling ao ,20 machine, and is a view on arrow III of Fig. 4; 0 4 1 q'o Fig. 4 is a diagrammatic view of film being formed 0 and filled on the machine, seen in the direction of arrow IV of Fig. 3.

Referring first to Fig. 1 of the drawings, a preformed pack 10 was prepared by overlaying two layers of flat polyvinylchloride film, each layer having a thickness of 130 micron, and r:adio frequency welding the two layers together along a seam 12 which is generally in the shape of 9 a U narrowing at the top with a curvature substantially symmetrical to the closed bottom end of the U. Seam 12 defines a bag with a filling neck 14 at the top of the bag.

Molten soap at a temperature of about 8 0 C was poured down the neck 14 into this bag, so as to fill the bag to capacity and provide an exceas extending up the neck 14 to the line indicated at 16. The pack was held upright and closed across its top opening by heat-sealing through the soap composition along the line 18.

The polyvinylchlorido material of the bag 0000: stretched at the temperature of the soap poured into it so 0 00 that as the bag was filled it distended and stretched to the 0 00 00 shape shown by Fig. 2a. This shape is little changed by 00 a 0 05 sealing as shown by Fig. 2b.

After sealing the filled pack was shaped so that 0 0 o~ o~its side view becam~e as shown in Fig. 2d. One possibility for doing this was to place the pack in a mould completely 0 surrounding it and allow cooling in the mould until the soap 00 had set. Such a mould needed to be slightly larger than the ea s*2O filled pack so as to avoid destroying the pack by attempting a 4 to confine it in a space which wae too small.

The alternative to this, which was preferred, was to press the pack between two plates 20 arranged substantially parallel to each other and to a plane containing the welded seam of the pack as shown in Fig. 2c.

To do this, these plates and the filled yack were ploced in a horizontal p~ 4 The upper plate carried a weight 22 so as to apply a pressure on the pack of about L. i4 0.2kgf/cm 2 The pressure so applied was maintained until the soap in the pack had cooled and This pressure applied to the pack served to maintain a pressure within the pack and thus to distend the film of the pack.

The resulting product had an attractive appearance, the cast bar being substantially "cushion" shaped and the polyvinylchloride film being a skin-tight and wrinkle-free fit, any creases which originally formed around the seam disappearing due to the film stretching and g'"aO0 accommodating itself in order to conform to the contours of 0 the pressed bar. The neck 14 was cut away, and a "skirt" of 0 *Co«0 film projecting around the seam 12 was also readily cut away 0 tSo in order to improve the overall appearance of the product 00 0 I yet further.

Figs. 3 and 4 illustrate diagrammatically the 00 e continuous forming and filling of packs. The packs are 04 °4 formed from flexible film laminate comprising a supporting material and a heat-sealable material at one face of the 0 0 0-o, 0 laminate. Two webs of the film laminate are drawn oft from a pair of supply reels 30 so that the heat-seala-I\ faces of 9 4 the film laminates contact each other and become the inside surfaces of packs. A, a first station 32, the two layers of film are sealed together along a pair of side seams 34 which extend generally vertically and have curved upper and lower end portions, as shown in Fig. 4. Fig. 3 shows station 32 just before the seams 34 are formed at this station; accordingly they are shown in chain dotted lines in Fig. 4.

After a pair of such seams 34 has been formed, the film is L drawn downwardly to bring the seams 34 to the positions indicated 34'. A filling nozzle 36 projects downwardly between these seams. Horizontal sealing is carried out at a second station 42. Sealing at this station occurs across the line 44 shown chain dotted in Fig. 4. It closes one pack and simultaneously forms the bottom of the next pack in succession.

o 09 00 0 000909 0 4 o 99 0 0 o 90 0 0' 0 0~ 0 09 0 0 00 As shown by Fig. 4 the pack 46 which is currently immediately below the station 42 has its bottom closed by 10 seam 44' formed in a previous cycle of operation. Before sealing takes place at the station 42 this pack 46 is filled with molten soap from the nozzle 36. Filling continues until an exceso of soap partially fills the pack 40, above, e.g. up to the level. 50. Sealing at the station 42 seals through the soap along the line 44 so forming an airtight seal to close the pack 46. Simultaneously it forms the bottom seam for the pack 48 next in succession. The filled packs are separated by shearoi 52 cutting horizontally through a previously formed seam 44".

Machinery for carrying out the process il1lustrated b~t Figs. 3 and 4 can be derived from conventional machinery for forming and filling four sided se .Ied sachets, Figs. 3 4 illustrate a process carried out down a single vertical column but it is f, zle to have a nujukor of ouch columns arranged sid1e by side.

For carrying out a process as I lvtstrated by Figs.

3 and 4 a suitable flrr material is 50 Micron Nylon (polyaniide) laminated with a 40 micron layer of Surlyn which

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12 is a heat-sealable cross-linked ethylene methacrylate copolymer. The Nylon does not stretch at the temperature 0 C) of the molten soap.

In a development of this process a further station is included at which the heat-sealable laminate is heated and stretched to a desired shape (while remaining flexible) by introducing air pressure between the two layers of film before a pack is filled with soap.

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Claims (7)

1. A method of casting a material comprising soap, a non- soap detergent or a mixture thereof into solid bar form, the method comprising: filling the material in a liquid or semi-liquid state and at an elevated temperature into a pack made at least substantially of flexible film, airtightly sealing the pack while the material is still aS. S 10 liquid or semi-liquid, OO allowing the material to cool and set to a substantially solid bar, and retaining the bar of set material in the pack as an airtight storage means, wherein the distance between the sides of the pack narrows adjacent both ends of the pack hereby the corners I narrowing between said sides of the pack, and/or the Sflexible film is heat-extensible or heat-shrinkable so as to deform while the material therein is still liquid or semi- 20 liquid, thereby to shape the solid bar formed in the pack.

2. Method according to claim 1 wherein the pack comprises two layers of its constituent film sealed together along a seam at the boundary of the pack, defining a bag or sachet with an opening through which to fill the material.

3. Method according to claim 1 or claim 2 wh, rn the A, material occupies substantially the whole internal volume of !Q Ini-Ld. .Ll J O. UL t carried out on a continuous basis. Moreover, a supply of empty packs can be stored in a flat or rolled form, or a 14 the pack.

4. Method according to any one of the preceding claims wherein sealing of the pack is effected by sealing through the material. 0 0 0e a 0 a 00 o 0 0 0 0 o oo S0 04 o 0 00 0 a i 0* Method according to any one of the preceding claims including sealing together two layers of flexible film to form the pack immediately prior to filling.

6. Method according to claim 5 wherein the sealing step defines at the same time at least a portion of the next pack to be filled. 15 7. Method according to any one of the preceding claims wherein sealing of the pack is effected by sealing through an excess of the material to form a seam which seals the pack wholly filled with the material and defines a portion of the boundary of the next pack to be filled.

8. A method according to any one of the preceding claims including distending the pack with internal pressure to shape the pack for obtaining a close fit to the material filled therein.

9. Method according to any one of the preceding claims including at least partly shaping the pack prior to filling. 15 Method according to any one of the preceding claims including contacting the exterior of the pack to control the shape of the pack during the setting of the material. one of the preceding claims. aoo, t oo O I 0 oa 0 o O0 oo DATED THIS 29TH DAY OF OCTOBER 1990 00 UNILEVER PLC o 9s By its Patent Attorneys GRIFFITH HACK CO. i*o Fellows Institute of Patent oOfo Attorneys of Australia 0 0 0 *o 8 S DD 000000e 0 00C