Field

This invention relates to improvements in a method of manufacturing a sachet. In particular to improvements in a method of manufacturing a sachet for a concentrated liquid product.

Background

Plastics pollution is a major current ecological concern. A recent drive amongst consumers has been to reduce plastics usage, leading to an increased awareness and demand for products that reduce or eliminate plastics usage.

One major source of household and commercial plastics waste are containers for storage of cleaning products such as household kitchen and bathroom cleaners. Such products are typically sold in containers of between 500ml - 750ml, although alternative container sizes are available. As noted above, commercial cleaning products used by retail and leisure industries generate a large amount of empty plastic container waste.

Refills that allow a consumer or cleaning company to reuse the original plastic container are available, allowing a consumer to replenish the contents of the original container. Such refills are typically either supplied as standard strength products or in concentrated form that must be diluted by the end user prior to use. Such refills often come as plastics pouches or smaller plastic bottles that contain the refill product and must be decanted into the original container prior to subsequent dilution (as necessary). However, the use of such refills merely mitigated the plastics problem, reducing the plastics use but not eliminating it. Furthermore such refills typically require decanting or a measured amount that is less than the full amount of the refill, leading to concentration issues with concentrated refills. There therefore exists a need for a refill product that at least ameliorates the above mentioned issues.

Summary

According to a first aspect of the present invention, there is provided a method of manufacturing a sachet for a concentrated liquid product, said method comprising the steps of: i) providing a sheet of water soluble film; ii) wrapping the sheet around a mandrel; iii) heat sealing edges of the sheet to form a tubular roll; iv) removing the mandrel; v) filling the tubular roll with a liquid concentrated product; and vi) heat sealing a base and a top of the tubular roll to form a sealed sachet comprising the liquid concentrated product.

In embodiments of this aspect, the sheet may comprise a polyvinyl alcohol film.

Steps iv) and v) may occur simultaneously, with the tubular roll filled as the mandrel is removed from the tubular roll. In this embodiment, the tubular roll may be filled from below. Filling may be by using a filling tube that runs within the mandrel.

In an embodiment the base and top of the tubular roll may be heat sealed using jaws. In such embodiments, step vi) may comprise the step of heat sealing the base of the tubular roll and then heat sealing the top of the tubular roll. This can ensure that the liquid concentrate is kept within the sachet. It can also be appreciated that this step may pressurise the liquid concentrated product within the sachet. This pressurisation may be controlled by adjusting the size of the jaws, and/or by sealing the top of the tubular roll from the very top downwards.

In one embodiment, rollers may be provided to grip onto the sealed edge of the sheet to advance the tubular roll towards the jaws. This removes the need for conveyors or the like.

Alternatively, step vi) may further comprises the steps of: a) gripping the base of the tubular roll using the jaws; b) heat sealing the base of the tubular roll; c) advancing the jaws from an initial position along an axial direction of the tubular roll to an advanced position; d) releasing the base of the tubular roll from the jaws; and e) returning the jaws to the initial position.

This alternative method reduces the pressure on the film when the tubular roll is advanced. Removing the rollers of the previous embodiment reduces the tension on the sealed edges of the tubular roll and helps to prevent weak points or failures. In an embodiment, this method may further comprise the step of: f) re-gripping the tubular roll at the initial position to form the sealed sachet. This forms the complete sealed sachet of liquid concentrated product. It can be appreciated that the length of the sealed sachet may be controlled by adjusting the travel of the jaws between the initial position and the advanced position. This provides fine control on the volume of the concentrated product within the sealed sachet without risking added tension to the film. Finally, the base of the tubular roll may be gripped by heat sealing the base.

In embodiments, the method may further comprise the step of cutting the top and bottom of the sealed sachets to form individual sealed sachets.

Further embodiments may include the step of providing perforations between top and bottom sealed sachets to allow the sachets to be torn apart.

In an embodiment, step iii) may comprise the step of heat sealing the edges of the sheet against the mandrel. Additionally or alternatively, one or more sealing jaws may be used to heat seal the edges of the sheet either together or against the sheet held by the mandrel.

The method may further comprise the step of adjusting a local temperature and humidity prior to performing any of the method steps to provide a desired physical property for the casing. The behaviour of such water soluble films varies according to the relative temperature and humidity - in one embodiment the humidity may be above 80% and the temperature may be above 25 degrees Celsius. The use of different temperature and humidity conditions can lead to poor sealing. The sheet may be tensioned prior to step iii). This tensioning ensures that the film is taught and seats properly around the mandrel and within sealing jaws. Over tensioning should be avoided - elongation of the sealed tubular roll caused by over tensioning may negatively affect reproducibility in size and weakens the seal, conversely limited tension helps the film run true and seat properly around the mandrel and within the sealing jaws.

It can be appreciated that steps iv), v) and/or vi) may occur simultaneously, or may be sequential, or any two of said steps may occur concurrently. The relative ordering and timings may be governed by when and how the tubular rolls are filled with the liquid concentrate. In other words, the tubular roll may be sealed at the base whilst both the mandrel is removed and/or liquid added.

A further step may involve trimming the heat sealed edge of the sealed sachet to aid fitting of said sachets through the neck of a suitable container.

According to a second aspect of the present invention, there is provided a sealed sachet formed by the method of any preceding claim.

According to an example of the present disclosure, there is provided a concentrated refill product for dilution into a solution, said product comprising a sachet; a volume of concentrated liquid product, said volume encased by the sachet; and wherein the sachet is substantially tubular in shape, having a diameter of less than 25mm, and wherein the sachet comprises a water soluble casing.

The present disclosure allows for easy insertion of a sachet into a suitable container for subsequent dilution. The present disclosure provides a convenient, plastics-free product that can be used to refill existing product containers, or to make new product containers from alternative containers, such as spray bottles, flip-top bottles and jars. The diameter of the sachet allows the product to be easily placed through the necks of such containers, which typically have an opening of 19mm or larger. The water soluble casing allows for easy product production, without leaving any waste packaging - the casing dissolves during production of the product.

The refill products are typically concentrated cleaning products or detergents, such as kitchen or household cleaners, oven or floor cleaners, window/glass cleaners or the like. It can be appreciated that although the products are primarily refill products intended to refill a similar original container, it may be used to make a new product.

In an example, the volume of concentrated product may be between 2.5ml and 20ml. Typically volumes of 5ml or 10ml may be used. The choice of volume is dependent, at least in part, on the product being diluted and the volume of solution required.

In examples, the water soluble casing may be at least partially dissolved to release the concentrated product into water to form the solution within, 5 minutes, with typical timings of, for example, 4 minute or less after submersion into the water at 15 degrees Celsius or warmer. It can be appreciated that rupture of the casing is only required to release the concentrated liquid product and allow dilution. Accordingly, the solution is typically formed quicker than the complete dissolution of the casing. The timings and temperatures are typical values - warmer water will reduce the dissolution time and vice-versa.

Typically the water soluble casing is made from a poly vinyl alcohol, although other suitable films may be used, such as starch or other dissolvable films. The sachet may be flexible and compressible for insertion within an opening of a bottle having diameter of 19mm or larger.

Typically the volume of concentrated product is coloured to allow identification of the concentrated product. Additionally or alternatively, the sachet may have writing on an exterior surface of the casing, again for identification and/or instructions or warnings.

According to a further example of the present disclosure, there is provided a method of diluting a concentrated product, said method comprising the steps of: a) providing an empty container, said container comprising an opening of 19mm or greater; b) placing a product according to the first aspect within the container through the opening; c) filling the container with water; and d) waiting until the sachet ruptures due to dissolution of the water soluble casing; e) optionally agitating the container to ensure an even solution; and wherein steps b) and c) are interchangeable.

In examples, the temperature of the water may be directed to the user. The temperature of the water may be 15 degrees Celsius.

In a further example, the method may comprise the step of placing one or more additional products according to the first aspect within the container through the opening. Accordingly, the concentrated refill product may be components used to produce the desired solution. For example, each refill product may comprise a concentrated constituent of a cleaning product that combines to produce the cleaning product.

The method may also comprise the step of printing onto the sealed sachet or onto the sheet. The printing may be used to identify the contents of the sachet and/or provide warnings, branding or other information.

It can be appreciated that features described in relation to one aspect may be equally applied to alternative complimentary aspects.

Brief description of Drawings

Embodiments will be described, by way of example only, with reference to the drawing, in which figure 1 shows a diagram of a concentrated liquid product according to at least one embodiment of at least one aspect of the present disclosure; figure 2 shows a schematic overview of a machine for producing the products shown in figure 1 ; figure 3 shows an alternative view of the machine of figure 2; figures 4a and 4b show schematic overviews of two positions of an alternative machine for producing the products of figure 1;.

It should be noted that the Figure is diagrammatic and not drawn to scale. Relative dimensions and proportions of parts of the Figures have been shown exaggerated or reduced in size, for the sake of clarity and convenience in the drawings. The same reference signs are generally used to refer to corresponding or similar feature in modified and different embodiments.

Detailed description of embodiments

According to one example of the present disclosure, a concentrated liquid product 10 is shown. In particular, the product 10 comprises a generally tubular sachet 20, having a top seal 24 and a bottom seal 26. A side seam or seal 28 runs along the length of the sachet 20. The seals 24-28 provide a liquid-tight seal around the sachet 20. The sachet 20 is made from a water soluble casing, such as polyvinyl alcohol. Other water soluble casings such as starch based casings may be used. The sachet 20 is flexible, allowing the sachet to be deformed.

The sachet 20 is filled with a concentrated solution of typically cleaning product, such as kitchen degreaser, bathroom cleaner, floor cleaner, oven cleaner or other similar product. Typical volumes of cleaning products include 5ml or 10ml depending on the product used and solution desired. The concentration of the liquid cleaning product within the sachet 20 is typically above 95%. By liquid cleaning product we refer to the combination of liquid cleaning concentrate, including surfactants, fragrance, dye and the like. Intended dilution concentrations include 1:25 or 1:100, with a typical container of between 250ml and 750ml used to dilute the concentrated solution. The concentrated solutions are usually coloured, for identification. Markings may also be placed on the exterior surface of the sachets, again to provide identification or other information.

The sachet 20 is typically less than 25mm in diameter. Typically a diameter of 22mm is used for the sachet, but ranges include 15-25mm diameters. The height of the sachet is typically around 2-13 cm or 15cm. In some examples the height is 12cm, but this can be varied depending upon the volume of concentrated liquid.

In use, a sachet 20 is typically placed within an empty container, such as a spray bottle, flip-top bottle or standard jar. Such containers which are recommended for use are between 250-750ml in volume. Spray bottles and flip-top bottles typically have an opening diameter of 19mm or more. The sachet, if the diameter is greater than the diameter of the opening, can be deformed to fit within and through the opening. In some examples, two or more sachets 20 may be used depending on the concentration required or to create a desired combined solution.

Water is then added to the container (or the water may already be within the container) up to a desired amount, typically 500ml. The temperature of the water broadly determines the speed at which the water soluble casing of the sachet 20 dissolves. However, within approximately 4 or 5 minutes enough of the casing has dissolved to rupture the sachet 20 and allow the concentrated product to be diluted with the water. Shaking or other agitation may be used to ensure an even dilution. Once diluted, the solution can be used as directed. Labels will be provided, where appropriate, to provide an indication to the user of the cleaning product within the reused container.

The sachets 20 are made by providing a sheet of water soluble film (such as polyvinyl alcohol), which is then wrapped around a mandrel or the like to form a tubular shape having open ends and an open seam from overlapping film. The overlapping film is then heat sealed either against the mandrel or between sealing jaws to form the side seam 28.

The tubular shaped film is then heat sealed at a bottom portion to form bottom seal 26 as well as top seal 24 of the previous sachet. The sachet 20 is then filled through the mandrel to the desired amount as the sachet is pulled down by rollers that clamp to the side seal 28. Once the desired amount is reached, the sachet is sealed at the top to form top seal 24 as well as bottom seal 26 of the next sachet. The sealed sachet 20 is then separated from the film. Desired amounts are typically 10ml or 5ml. Heights of the sachets are approximately 4-13cm. Diameters of the sachets are approximately 15-25mm, more particularly 22mm.

The temperature and humidity at which the sachet 20 is formed plays a role in ensuring that the properties of the water soluble casing are consistent and suitable for both ensuring that the seal doesn’t leak and that the flexibility of the sachet 20 is maintained. In one example the temperature used is at or above 25 degrees Celsius, with a relative humidity of 80% or higher.

The use of the sachets of the present disclosure allows for the reuse of a wider variety of containers than previously possible. The sachets are ecologically friendly and are easy to store and deliver by post.

Figure 2 shows an embodiment of how the sachets shown in figure 1 may be made. In figure 2, a series of stages are shown. A sheet of water soluble film (as described above) is provided. The film is passed into a first stage 110. In this stage the sheet is wrapped around a mandrel and edges 28 of the sheet, which overlap beyond the mandrel are heat sealed together to form a tubular roll 25.

The mandrel is then removed and the tubular roll is filled with a desired liquid concentrated product. Rollers 120 arranged on either side of the edge 28 grip the edge 28 of the tubular roll 25 to advance the tubular roll 25 via rotation of the rollers 120. The rollers 120 advance the tubular roll towards a set of jaws 130 that clamp against the tubular roll to form a seal. The seal is typically formed by heat sealing.

The seal typically forms the top 24 of one sachet and the base 26 of another sachet. It can be appreciated that the tubular roll 25 advances through the system with the base 26 of a sachet being sealed before the rollers 120 advance the tubular roll by a desired amount (which determines the length and therefore volume of the sachet) before the jaws seal a top of the tubular roll 25 to form a sealed sachet 20. A cutter may be used to separate sachets 20. Alternatively, perforations may be added between tops 24 and bases 26 of sachets 20 to allow a user to separate the sachets.

Figure 3 shows a top view of the rollers 120 and the tubular roll 25. It be seen how the rollers 120 grab the edge 28 of the tubular roll 25 to advance the tubular roll through the system.

An alternative embodiment is shown in figures 4a and 4b. In this embodiment the rollers 120 are replaced. Instead, the jaws 130 act to advance the tubular roll 25 through the system. As shown in Figure 4a, the jaws 130 seal (such as by heat sealing) the tubular roll to form a base 26 of a sachet 20. The jaws then maintain their grip on the base 26 and advance in a axial or longitudinal direction (i.e. along a direction parallel to the length of the sachet) to advance the tubular roll 25. Once the jaws have moved to an advanced position (as shown in part in figure 2b), the jaws 130 release the heat sealed base 26. The jaws then return to the initial position shown in figures 2b and 2a. The jaws 130 then re-grip the tubular roll and form a seal, which provides the top 24 of the previous sachet 20 and the base 26 of the next sachet.

Again, a cutter can be used to, along with perforations.

From reading the present disclosure, other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features which are already known in the art of design realisation and extrusion and which may be used instead of, or in addition to, features already described herein.

Although the appended claims are directed to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalisation thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention.

Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination. The applicant hereby gives notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.

For the sake of completeness it is also stated that the term "comprising" does not exclude other elements or steps, the term "a" or "an" does not exclude a plurality, and reference signs in the claims shall not be construed as limiting the scope of the claims.