ZA200509586B

ZA200509586B - Device,equipment and method for the manufacture of cleaning articles with a flowing mass and having complex shapes and use of the cleansing articles

Info

Publication number: ZA200509586B
Application number: ZA2005/09586A
Authority: ZA
Inventors: Patrice Santana Caceres; Cleverton Antonio Camargo Sechi; Silva Joao Carlos Da
Original assignee: Unilever Plc
Priority date: 2004-12-30
Filing date: 2005-11-28
Publication date: 2008-10-31
Also published as: CN1804020A; CZ2005808A3; BRPI0406493A; MXPA05014003A; CZ302621B6; CN1804020B

Description

»,J2784 (TC) CT

The present invention is related to the production of cleansing articles. More specifically, the invention discloses novel solutions for moulding or stamping cleansing articles such as soap bars having complex shapes. The device, equipment and method of the invention comprise the use of dies having means for conveying any gas from and into the die cavity, thereby providing the mass production of cleansing articles with sophisticated formats without incurring in the difficulties usually associated thereto.

The art of large scale production of cleansing articles such as soap bars is in continuous development. Soap or non-soap detergent articles are traditionally produced by shear working/homogenization of the formulation, followed by extrusion and stamping. This procedure is only suitable for detergent bar formulations which are thermoplastic, or which are not shear sensitive. While soap bar formulations in general can be produced by either casting or molding, some difficulties arise when it is desired that they present a complex shape, such as long pins arising out of one its surfaces or having acute angles, among many others.

Casting of a melt into bars is a process usually employed for producing highly transparent soaps. The technology presently employed involves many manufacturing operations such as casting of molten soap into long bars of desired cross section (Schist moulds), cooling, bar ejection, bar

J

, J3784(C) CT maturation, billeting, chamfering, billet maturation and stamping to produce individual soap tablets. Although the maturation time may be reduced or completely eliminated by employing certain formulation variations, overall this method is highly labour intensive, and is very expensive.

Casting in pack, on the other hand, is a process which involves casting a molten soap blend into a shaped transparent pack or sachet, in which it is solidified and sold as such. Although highly transparent soaps can be produced by this technology, the process is very expensive and maturation, if required, is very slow.

Individual casting in flexible moulds is a method disclosed in JP 610266938 to Kanebo, Ltd., in 1984. This document describes a method involving casting a melt into a "thin moulding plate" which is flexible or elastic and is made of synthetic resins. This process simplifies the manual operations involved in the conventional technology of making +transparent soaps by eliminating the steps of billeting, chamfering, stamping and polishing.

The above-mentioned technologies are generally related to the production of cleansing articles having complex shapes.

However, with the resurgence of the specialty soap and personal care market exemplified by various personal care poutiques, personal washing bars that have more complex shapes and structures are being offered. One example is the so-called massaging bar, characterized by having protrusions or nubs of various shapes arising from a common surface.

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Current “projection bars”, i.e., cleansing bars that have one or more projections arising from at least one common surface, are made either by hand casting, hand stamping or through an automatic production using an injection mold, blow mold, valves or dies. In the conventional dies for soap stamping, no system to evacuate the air trapped inside the dies has been so far described. Due to be a hand stamped process, the air comes out naturally once it is twice or three times stamped to form a bar. In this sense, it is also a time and cost consuming process, not feasible to offer a mass production for soap bars.

Also, in conventional dies for ordinary non-complex soap shapes, the bar is generally designed with flat continuous smooth and non-depressed surfaces, situations in which the dies are easily and completely fulfilled. These dies comprise a single air-feeding channel in the die plate that pushes the extractors, which are the elements that move forward and backwards when actuated by the air supply to detach the bar from the die surface. When the extractor actuates, air also goes out and expels the soap from the cavity. The dies are usually divided in two parts by the splitting line, which is in the center part of the die, and it is called a parallel belt. The die area is divided in the middle, and this way half of it stays in one side of the die, and half on the other.

Soap bars are manufactured by introducing into a die a block of relatively soft material from which the soap bar is to be formed. Typically, dies are provided with cavities, through which cooling means passes to cool the dies. A problem with n J3784(C) CT the above mentioned machines is that the soap bars formed frequently stick to the soap die because the methods of cooling have insufficient capacity and flow rate, particularly with glycerin/translucent soaps. Still further, the above mentioned machines are relatively slow due to insufficient cooling capacity.

An approach for addressing this problem is disclosed on patent US 6,511,626 “Die for manufacturing soap bars”. This document describes a machine and a method to manufacture soap bars, the machine involving a die assembly having a pair of die blocks which support co-operating dies. Liquid nitrogen is delivered to the two dies via a throttling passage to cool the soap material being formed, thus facilitating its removal from the die.

The so far disclosed approaches require expensive and/or complex devices. These systems do not provide simple solutions for the air entrapment problem within the dies when the knobs are fulfilled with the soap mass. patent US 6,554,246 “Casting of shaped soft solid articles” discloses a die for casting shaped solid detergent articles, the die being made of two rigid complimentary dies which upon engagement define a cavity corresponding to a desired shape of the cast article. The engaged dies form a reservoir which on one side is open to receive cast melt, and on another side is open to the cavity. This document therefore teaches the use of a rigid two part split die for individual casting of solid shaped detergent articles such as soap/non-soap detergent tablets, which gives an

»J3784(C) CT unblemished and bubble free product in a form that is dictated by the shape of the die. The die is also designed for efficient cooling of the cast article, but no complex shape cleansing article can pe produced with this kind of die.

The present invention seeks improvements to overcome these and other problems of the known art.

Unless otherwise specified, in the present: invention the expressions wgoft” or “flowing soap mass” ox simply “flowing mass” relates to a mass for forming a cleansing articles, such as a soap bar, and which is in a form softer than the end soap bar so that it can be poured into a die cavity.

Unless otherwise specified, as used in the present invention, the expression “complex shape” comprises shapes either unusual for soap bars, or that may present difficulties during a mass production, such as causing the soap bar to present brittle portions or uneven surfaces, among others difficulties.

Unless otherwise specified, as used in the present invention, the expressions “air” or “gas” are used in an equivalent manner to designate any gaseous compound present inside the cavity of the device into which mass for forming the cleansing article is poured. In addition, it is pointed out that the term “conveying a gas’, used in the present text, refers to introduction and extraction of any gas in and out of a die cavity.

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One solution provided by the present invention is the development of a system that can fill the dies completely so that the product will have the expected shape in an automatic production situation using the currently available machine capabilities. This solution provides the feasibility of producing soap bars with highly complex shapes in automatic stampers.

It is therefore an object of the present invention to be able to provide novel devices used for forming by either moulding or stamping cleansing articles such as soap bars.

The terms “device” or “die” or “die casting” are mentioned as synonyms, as it is assumed by the invention that the object of the present invention is a mould that comprises a cavity for manufacturing a cleansing articles. In a preferred embodiment, the device is capable of forming a cleansing article having complex shapes such as articles having one or more projections arising from a main body.

In one aspect of the present invention, being therefore an object of the present invention, it is disclosed a device for moulding or stamping cleansing articles wherein means for conveying of any gas from and into the cavity through the inferior part of the cavity are provided. More specifically, the means for conveying of any gas from and into the cavity is a valve-like air exhaust system.

In a preferred embodiment of the invention, the valve-like air exhaust system is actuated by a spring operated system.

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It is therefore another object of the present invention to be able to provide an airless die cavity by means of a spring-operated system.

In a preferred embodiment of the invention, the valve-like air exhaust system is actuated by an air/vacuum operated system. It is therefore another object of the present invention to be able to provide an airless die cavity by means of an air/vacuum operated system.

The device of the invention may be advantageously incorporated into equipments for the mass production of cleansing articles. It is therefore another object of the invention to be able to provide equipment for the mass production of cleansing articles, the equipment comprising the device of the invention above-mentioned.

It is also an additional object of the present invention to provide a method for the manufacture of cleansing articles, such as soap bars, that include one or more projections arising from a main body.

The invention will be described by way of example only with reference to the accompanying drawings, in which: - Figure 1 shows the device of the present invention in one of its preferred embodiments which uses a valve with movable plate; and - Figure 2 shows the device of the present invention in another preferred embodiment.

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During the development of the present invention, the inventors envisaged that while forming a soap bar from a flowing or soft mass, the gas inside the die cavity caused the soap bar to present several problems such as becoming brittle or with uneven surfaces. Therefore, the inventors developed a device that comprises a valve-like air exhaust system, which actuates in both extracting gas from the die cavity.

In a first preferred embodiment, the invention comprises a device having a die cavity whose underneath portion is provided with means for conveying the air from and into the die cavity assisted by a spring operated system.

In another preferred embodiment, the invention comprises a device having a die cavity whose underneath portion is provided with means for conveying the air from and into the die cavity assisted by an air/vacuum source.

The latter embodiment the system is provided with passages, so to speak, underneath the plate area to allow the air to flow in and out of the die cavity. among all the advantages described above, the principal one is that the technology described can make viable production of soap bars with highly complex shapes in automatic stampers.

More specifically, the device or die of the present invention is used for forming cleansing articles having complex shapes, the devices comprising at least one cavity

. J3784(C) CT for forming the articles, and the cavity comprising an inner surrounding wall that defines the axial contour of the cavity towards an open end and a lower wall that defines the underneath portion of the cavity, wherein the device comprises means for conveying any gas from and into the cavity.

The present invention will be now described with reference to one preferred embodiment in which the underneath portion of the die cavity comprises at least one knob cavity to form a soap bar with at least one protrusion that arises from the main body.

In this preferred embodiment of the invention, at the inner part of the die cavity, on the bottom of the cavity, there is a valve-like air exhaust system which comprises a metallic plate on the top of a pin surrounded by a spring secured e.g. by a scroll with a ring. The plate stays in an upper most position than the bottom of each of the cavities disposed in the underneath portion of the dies to create a gap to outlet the air. During stamping, the soap mass pushes the plate downwardly, thus the air so pressured leaves through the gap until the moment when the plate reaches its final position at the underneath of the knob cavity. At this stage any gas has been completely gone, and the soap mass fills the die thoroughly.

In another embodiment of the present invention, at the inner part of the die cavity, on the bottom of the bar knobs, there is a valve-like air exhaust system which comprises a fixed pin provided with a plate with a pending surrounding

_ J3784(C) CT surface having a plurality of grooves spaced one from the other along its periphery. The plate stays in the same level of the bottom of each of the knobs cavities in the dies, defining a portion of the bottom of the dies. During stamping, the soap mass starts to be poured into the die cavity. The air inside the cavity is removed by vacuum through the grooves. At this stage any gas is completely gone, and the soap mass fills the die thoroughly.

The plate further comprises a substantially planar disc with an upper surface toward the open end of the cavity and a pending surrounding surface opposite to the upper surface and downwardly to which a pin is secured.

The present invention will now be further described by reference to preferred embodiments as showed in Figures 1 and 2. A die (1) for casting shaped, solid detergent articles comprises a cavity provided with at least one knob cavity (2), and means for conveying any gas from and into the cavity, specially from the knob cavity(ies) corresponding to the desired shape of the cast article used for pouring the soap bar masses thexein.

More specifically, the means for conveying any gas from and into the cavity is placed in the underneath portion of the cavity, comprising a valve-like air exhaust system. In the embodiment showed in Figure 1, the valve-like air exhaust system comprises an axially movable plate (3) on the bottom of each knob cavity (2) secured to a pin (4) around which there is a tube (5) defining a passage (6) that connects the knob cavity (2) in the top and an outlet channel (7) in the

_J3784(C) CT bottom. Also, there is a gap (8) formed between the plate (3) and the top end of the tube (5). The gap (8) allows the gas to go out from the cavity as the soap bar mass (10) is filling the cavity.

In addition, the movable plate (3) moves along its vertical axis with the aid of a spring (9) which surrounds said pin (4); especially the spring (9) is placed between the bottom portion of the plate (3) and the bottom end of the pin (4).

The die (1) in Figure 1 is in a condition where the cavity is being filled by the soap mass (10), so as high level of gas goes out the die through the gap (8) and outlet channel (7), so as very high level of gas goes out the device (1) through the outlet channel (7) towards the outside of the dies (1).

Now, with reference to the Figure 2, which shows another preferred embodiment of the invention, it is observed that the valve-like air exhaust system differs from the one showed in Figure 1 mainly because there is no spring, and the plate is not movable. More specifically, in this case the valve-like air exhaust system is operated only by a air/vacuum system and comprises a pin (4) provided with a fixed plate (13) on the top of it having a plurality of grooves (18) spaced apart one from the other on its peripheral surface, to allow the gas to go out through the grooves (18) to the outlet channel (7) as the soap mass (10) is poured into the cavity.

Another important feature of the present invention 1s that the conveying of any gas from the cavity and through the

. J3784(C) CT passage toward the outlet channel is realized by the pressure of the flowing mass poured into the cavity through the open end of the cavity. In an alternative embodiment, the conveying of any gas from the cavity toward the outlet channel is realized by the suction promoted by an air/vacuum source, which is connected to the end of the outlet channel.

The moulding devices or dies of the invention are manufactured from any rigid material, e.g. metals such as bronze and aluminum and their alloys. Each die is provided with an internal surface, the size and shape of which may vary depending on the desired form of the final product.

Typically for a soap tablet (bar) of 15 g to 150 g the volume of the total cavity would range from 10 to 170 ml, and the shape may be circular, oval, square, rectangular or any other form as desired. The inside surface of the cavity may be flat, concave or having any complex shape or any other shape as desired. Alternatively the inner surface of the cavity can be coated with a suitable coating to provide a smooth surface finish, and easier soap bar extraction from the die.

The device of the invention may be advantageously incorporated into equipment for the mass production of cleansing articles. It is therefore another object of the present invention to be able to provide equipment for the mass production of cleansing articles, wherein the equipment comprises the dies of the invention as disclosed above.

According to a further aspect of the invention, there is provided a method for manufacture of cleansing articles with

\ J3784(C) CT flowing mass and having complex shapes, which comprises the steps of: i. providing a flowing mass for manufacturing a cleansing article; ii. pouring the mass into a device for molding or stamping cleansing articles comprising means for conveying of any gas from and into the cavity; and iii. extracting the solidified cleansing article from the die.

Preferably, the die is cooled before the mass is poured therein, such that the internal surface of the die is at a temperature below the solidification temperature of the mass. The method is suitable for manufacturing shaped detergent articles such as tablets of soap and/or non-soap detergent, for example for personal washing or for washing fabric. Most particularly, the method may be used for manufacturing soap bars for personal wash skin treatment.

The method may be carried out in a continuous manner by having a plurality of dies circulating through a mass feeding station where each die is filled with the mass, and subsequently taken through the steps of complete solidification and extraction before being recycled again.

The soap mass is poured into the die such that the cavity is completely fulfilled. The die can be optionally cooled to a temperature ranging from -9 to -22°C..

The present invention presents innovative characteristics in an alternative process to fulfill dies completely in order

, J3784 (C) CT to have the expected shape, in an automatic production situation, using the currently available machine capabilities. This process allows the production of soap bars with highly complex shapes in automatic stampers. The developed method is useful to produce molded or stamped articles, preferably soap bars, used for personal cleansing that include one or more projections arising from a main body.

The developed method of producing molded or stamped soap bars through the dies can also be described as follows: 1) the die has in the inner part of its cavity, on the top of the bar knobs, a system with a metallic plate on the top of a pin with a spring secured by a scroll and a ring; 2) the plate stays in an upper level compared with the bottom of each of the knobs in the dies to create a gap to outlet the air. During stamping: 1) the soap mass pushes the plate; 2) the air pressured leaves through the gap until the moment when the plate reaches its final position, at the final level on the bottom of the knob cavity; 3) at this stage, the air is completely gone; and 4) the soap mass fills the die thoroughly.

The developed method of producing molded or stamped soap bars through another embodiment of the dies can also be described as follows: 1) the die has in the inner part of its cavity, on the top of the bar knobs, a system with a metallic plate on the top of a pin; 2) the plate comprises a plurality of grooves and it stays in the same level of the bottom of each of the knobs in the dies. During stamping: 1) the soap mass is poured into the cavity; 2) the air

} J3784 (C) CT ~- 15 - pressured is conveyed through the grooves until the mass completely fills the cavity; 3) at this stage, the air is completely gone; and 4) the soap mass fills the die thoroughly.

Besides the use of a valve with a movable or fixed plate connected with the air/vacuum system, it could be possible to reach the same results by using a hole in the top of the knobs or toward the side to exhaust the air trapped, or a even porous surface through which air is conveyed. )

Claims

J3784 (C) CT - 16 =~ CLATMS

1. A device for the manufacture of cleansing articles with a flowing mass and having complex shapes, comprising at least one open cavity for forming the articles, the cavity comprising an inner surrounding wall defining the axial contour of the cavity towards an open end and a lower wall defining the underneath portion of the cavity, including by means for conveying of any gas from and into the cavity.

2. A device according to claim 1, wherein the means for conveying of the gas from and into the cavity comprises a valve-like air exhaust system.

3. A device according to claim 2, wherein the valve-like air exhaust system comprises a plate on the underneath portion of the cavity secured to a pin around which there is a tube defining a passage upwardly ending on the underneath of the cavity and downwardly connecting to an outlet channel.

4. A device according to claim 3, wherein the plate further comprises a substantially planar disc with an upper surface facing towards the open end of the cavity and a pending surrounding surface with a lower surface opposite to the upper surface and facing downwardly to ‘which the pin is secure.

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5. A device according to claim 3 or claim 4, wherein the device is spring operated being the plate axially movable.

§. A device according to any one of the preceding claims, wherein gas is removed from the cavity by conveying through a gap and passage into an outlet channel.

7. A device according to claim 6, wherein conveying of gas through the gap and passage to the outlet channel is by pressure of the flowing mass poured through the open end of the cavity.

8. A device according to any one of claims 4, 6 or 7 wherein the pin secured to the lower face of the substantially planar disc is axially surrounded by a spring supporting the lower face of said disc. 50

9. A device according to any one of claims 1, 2, 3 or 4 wherein conveying of gas through passage to the outlet channel is by suction of the gas by vacuum.

10. A device according to claim 9, wherein the pending surrounding surface of the plate is provided with a plurality of grooves spaced apart one from the other along its periphery.

11. A device according to any one of claims 9 or 10, wherein an air/vacuum source is connected to an end of the outlet channel,

12. A device according to any one of the preceding claims, further comprising forming cleansing articles by molding.

13. A device according to any one of claims 1 to 11, further comprising forming cleansing articles by stamping.

14. An equipment for manufacture of cleansing articles with a flowing mass and having complex shapes, the equipment comprising at least one open cavity for forming the articles, the cavity comprising an inner surrounding wall defining the axial contour of the cavity towards an open end, and a lower wall defining the underneath portion of the cavity and further comprising means for conveying of any gas from and into the cavity. :

15. The equipment according to claim 14, wherein the means for conveying of any gas from and into the cavity comprises a valve-like air exhaust system.

16. The equipment according to claim 15, wherein the valve-like air exhaust system is spring cperated.

17. The equipment according to claim 15 or claim 16, wherein the valve-1like air exhaust svsten is air/vacuum operated.

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18. The equipment according to any one of claims 14 to 17, characterized by forming the cleansing articles by . moulding.

19. The equipment according to any one of claims 14 to 17, characterized by forming the cleansing articles by stamping. :

50. A method for the manufacture of cleansing articles with a flowing mass and having complex shapes, yherein the method comprises at least the steps of: i) providing a flowing mass for manufacturing a cleansing article; ii) pouring the mass into a device for molding or stamping cleansing articles comprising means for conveying of any gas from and into the cavity; and iii) extracting the solidified cleansing articles from the device.

21. A method according to claim 20, wherein the device comprises a valve-like air exhaust system.

22. A method according to claim 21, wherein the valve-like air exhaust system is spring operated.

23. A method according to claim 21 or claim 22, wherein the valve-like air exhaust system is air/vacuum operated.

J3784(C) CT v

24. A method according to any one of claims 20 to 23, wherein the device is cooled before the step of pouring the mass into a device.

25. A method according to the claim 24, wherein the device is cooled to a temperature ranging from -9 to -22°C.

26. A method according to any one of claims 20 to 25, which may be carried out in a continuous manner by having a plurality of dies circulating through a mass feeding station where each die is filled with the mass and subsequently taken through the steps of complete solidification and extraction before being recycled again.

27. Use of the cleansing articles manufactured according to any of claims 20 to 26.

28. A device according to the invention, substantially as hereinbefore described or exemplified.

29. An equipment according to the invention, substantially as hereinbefore described or exemplified.

30. A method according to the invention substantially as hereinbefore described or exemplified. DATED THIS 28TH DAY OF NOVEMBER 2005 SPOOR & FISHER APPLICANTS PATENT ATTORNEYS