Soap wrappers

The present invention relates to a soap bar package having opposing longitudinal ends, the package having a stiffening member including a rigid sheet material, some of the outer surfaces of which are provided with plastic material, and including a stiffening member laterally wrapped around the entire length of the bar.

In the past, much effort has been made to obtain fungicide-containing papers and a stiffening plate for soap packaging. Since cellulose, which is the main constituent of paper, is an excellent growth medium for molds, especially under wet and warm conditions, the use of fungicides (known in the US as antimicotic) is essential for soap wrappers to prevent soap from spoiling. These ingredients often act as fungus inhibitors and prevent the initiation of mold growth.

Unfortunately, the amount of fungicides that can be safely used in soap packaging is limited, mold can develop resistance to fungicides after prolonged exposure to them, leading to the need to change the fungicide approximately every 7 years. Carbendazim and Thiabendazole have been used in the past, but these agents are now ineffective in tropical conditions, and papermakers have to put a lot of effort into developing the next second generation fungicide. This requires a long program of testing and grading which, once certain types of mold are resistant, will have to be repeated if this mold prevention procedure is to be followed.

It is known to use a plastic film for wrapping a soap. In particular, in a known soap bar package, the soap is wrapped with a conventional paper stiffening element, and the stiffening element is completely wrapped by a foil package, which is usually a laminated film composed of two layers. oriented polypropylene. The problem is that this solution only improves the appearance of the soap bar which is enhanced by the high gloss of the plastic film. However, this solution does not prevent attacks by mold, since the use of a cellulosic stiffener plate makes it susceptible to such attacks.

Mold attack is accelerated in warm and humid conditions, and because the soap bar contains free water when first packed, the package and stiffener are very wet initially. Thanks to the use of paper packaging, water is quickly drained through the paper and the folded, glued ends of the packaging.

We have found that if the soap bar has a stiffening member wrapped around at least the length of the bar, each outer surface of which is provided with a plastic material, the formation of mold inside and on the package can be completely prevented.

Moreover, the conventional stiffening plate largely loses its strength after being soaked in moisture. Its ability to protect the soap in transit can therefore be significantly reduced. However, if the stiffener comprises an inner plate and two outer plastic surfaces, the wicking ability will be significantly reduced, leading to a reduction in the loss of stiffness.

Likewise, if furthermore the package wrapped around each soap bar and stiffening member comprises foil material, the at least one outer surface of which is provided with plastic material, the growth of mold inside and on the surface can be completely eliminated.

Moreover, as shown with reference to the attached drawing, since only the folded ends of the package provide a path for moisture escape, the rate of water loss is greatly reduced, ensuring that the required amount of water remains inside the cube. On the other hand, plastic film packaging is a very good moisture barrier.

In particular, in microbiological laboratory tests using molds that proved resistant to Carbendazim, both the plastic films and the plastic-coated plate were tested for mold attack and the test results showed that they were completely mold resistant.

It has been found that even when using a plastic coated double plate stiffener, the fungus does not penetrate the edges.

From the patent description US4754874 a soap is known in a transparent plastic container, the shape of which follows the shape of the soap. Moreover, the package as a soap dish can be used reversibly, the bottom can be the top surface and vice versa.

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It further comprises an elastic top surface closure and transverse segments forming drainage channels for removing water from the package. This solution uses a grooved surface of the package to prevent the soap dish from slipping.

A soap bar package having opposite longitudinal ends, a stiffening member having a rigid flap material, some of the outer surfaces of which are provided with plastic material, and a stiffening member wrapped laterally around the entire length of the bar on which mold formation inside and on the package is controlled, characterizes ensure that at least part of the stiffening material is transparent and is so folded that completely surrounds the soap bar and the stiffening member, and the package comprises a foil material which is at least in part transparent.

The transparent part of the package is arranged over the transparent part of the stiffening member.

Preferably the entire package is made of a transparent material.

The foil material is 5 to 50 μm thick.

At least part of the outer surfaces of the package are provided with plastic material.

The packaging is heat sealed or hermetically sealed.

The stiffness of the rigid sheet material is at least 3 Taber stiffness units in both the longitudinal and transverse directions.

₂

Preferably, the stiffening member has a weight per unit area of ​​50 to 200 g / m 2².

At least one outer surface of the rigid sheet material is of a thermoplastic material that contains from 5 to 30% by weight of filler or blowing agent.

Preferably, the thermoplastic material comprises an inert inorganic filler which is talc or clay.

Preferably, the rigid sheet material has a thickness of from 50 to 250 µm.

The thermoplastic material is selected from the following materials: polypropylene, polystyrene, acrylic-butadiene-styrene copolymer, polyethylene terephthalate and PVC.

It preferably has an embossed pattern selected from the group consisting of words and logos or a decorative pattern or soap novel features selected from the group consisting of stripping and transparency and in that the part of the stiffening member that covers the pattern or pattern is transparent so that the pattern or the pattern is visible through the stiffening member.

Preferably, all of the rigid sheet material is a transparent material.

Preferably, the stiffening member completely surrounds at least the entire length of the ankle so as to form a sleeve of rigid sheet material.

The provision of a stiffening member, at least part of which is transparent, allows the soap to be viewed through the stiffening member. The use of traditional paper-filled stiffeners has hitherto prevented the use of transparent stiffeners. In addition, the use of plastic stiffeners improves the resistance to mold attacks.

Typically, the filler is an inert inorganic filler such as talc or clay. Such fillers allow you to increase stiffness.

The thermoplastic material of the stiffening member panel is selected from a variety of film types suitable for this application. Typically these are polypropylene, polystyrene, acrylic-butadiene-styrene copolymer, polyethylene terephthalate and PVC. These films can undergo a mono or bi-orientation process to improve certain properties, such as, for example, transparency, barrier ability, stiffness. Of course, straight films can also be used. The films are in a form to impart maximum stiffness, and typically a suitable polystyrene may be BOPS or HIPS, and a suitable PET may be A-PET.

It is desirable that the stiff sheet material does not roll off the roll on which it is stored and that it wraps around the bar of soap, around the entire periphery of the longitudinal surface of the bar of soap, after which it should remain rolled up to form a sleeve surrounding the bar of soap. The longitudinal ends of the soap bar are not surrounded by a stiffening member so that the soap can be easily removed for use.

The package may be a foil material having a paper core coated on each surface with a plastic material. It is also possible for the package to be an all-plastic, thermoplastic film material of which at least one part is transparent.

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A single metallized film may be used to improve the appearance and improve barrier properties. Moreover, the metallized element may be removed in a portion to create a window through which soap can be seen.

The package, when wound around the soap bar and the stiffening member, has edge portions that overlap. This allows the edge portions to be fastened together. The fastening may be accomplished by applying an adhesive between respective opposing surface areas, for example by applying an adhesive to different areas of the edge portions, folding the package and applying pressure. However, the edge portions are attached to each other by welding so that at least the outer layers of the film material of the package are heat-sealed plastic material.

Moreover, the edge portions are free of printed material.

The foil material of the package comprises at least one layer of biaxially oriented polypropylene suitable for welding. The film may be a laminate of a biaxially oriented polypropylene layer with a low density polyethylene layer.

The package may be a laminate of a heat-sealable film, the inner surface of which may contain a printed material, and a laminating adhesive such as a hot melt material is applied therebetween. A special BOPP film that is suitable for welding. A laminate of PET, nylon or low density polyethylene film, bonded, for example with a melt adhesive, to the foil to be sealed.

The soap bar package may be produced by the method of the following steps of wrapping around at least the entire length of the soap bar of the stiffening member such that the stiffening member is laterally wrapped around the bar. Wrapping the soap bar and the stiffening member with the package so as to completely enclose the soap and the stiffening member and the edge portions of the package overlap. Gluing, preferably by welding, at least some portions of the overlapping edge portions to firmly hold the package in place.

The stiffening member is formed by casting a molten thermoplastic material such as polypropylene or polystyrene. A typical soap package may include a package that may be entirely made of plastic material or plastic coated paper. The finished package can be heat sealed on both sides in high speed machines. However, the hot melt adhesive may be used for bonding in slower packaging lines.

Furthermore, it may include a stiffener which may be either 100% plastic or a foil filled with plastic or paper or cardboard coated on both sides with plastic, at least part of the stiffener being transparent.

Embodiments of packages and stiffeners that provide mold-resistant soap packaging are as follows.

Biaxially oriented, coextruded 5-55 μm polypropylene films with a printed and varnished surface are bonded together and the edge portions are free of ink and varnish. If required, a print can be applied to the back side to avoid damage from abrasion during transport.

15-35 µm thick BOPP films, printed on the back side and press coated on an ink, with a 12-35 µm layer of low density polyethylene (LDPE) or linear low density polyethylene (LLDPE), or mixtures thereof. Instead of a LDPE or LLDPE homopolymer, a copolymer of each may be used for coating. Moreover, such a homopolymer or copolymer may additionally contain from 2 to 10% ethylene vinyl acetate (EVA) copolymer units, especially in LDPE, to improve bonding.

Two or more BOPP films, 10 to 35 µm thick, front and back laminated to heat-sealed surfaces. The print can be closed between the layers of foil.

BOPP film with a thickness of 10 to 35 µm laminated with LDPE or LLDPE film with a thickness of 10 to 50 µm. Combinations of LDPE and LLDPE can be used in the film, and 2 to 10% ethylene vinyl acetate copolymer can be added to the LDPE film to improve bonding.

100% high density polyethylene film 10 to 50 µm thick, with a printed and varnished surface, the joint areas being free of ink and varnish.

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- 55 μm polyethylene, polypropylene, PVC, PET films with a heat applied coating (typically melted hot wax) applied to the back side. Alternatively, the coating may be of the cold applied type where high temperature is not used in the joining process.

The stiffener materials which are at least in part transparent are a 100% cast film made of plastic or a cast film made of plastics filled with inert inorganic fillers or blowing agents to increase stiffness. Examples of this type of film are polypropylene, polystyrene, acrylic / butadiene / styrene, PVC or PET having a thickness of 20-250 µm. Fillers such as talc or clay may be present in an amount of 10-30%.

In addition, plates coated on both sides of 6 - 35 µm are used as the stiffener material. polyethylene. Combinations of LDPE and LLDPE can be used. The quality of the board is not critical and white particle board, Duplex, Triplex or 100% bleached or unbleached Kraft boards from 100 to 200 gsm may be suitable².

Said packaging and stiffener materials can be used together in any combination.

It is particularly advantageous if no paper is used at all in the packaging solution.

Preferred embodiments of the invention will be illustrated with reference to the drawing which shows a graph of the weight loss due to moisture loss over the period after packaging a freshly made bar of soap.

Example A to H

The following packaging systems were tested for mushroom growth and weight loss.

<td>Example</td><td>Package</td><td>Stiffener³</td><td>Connection⁴</td>

<td>AND</td><td>BOP¹</td><td>Paper⁵</td><td>Partial connection</td>

<td>B</td><td>BOP¹</td><td>Paper⁵</td><td>No linking</td>

<td>C.</td><td>BOP¹</td><td>Paper⁵</td><td>Hermetic joining</td>

<td>D</td><td>BOP¹</td><td>Plastic</td><td>Partial connection</td>

<td>E.</td><td>BOP¹</td><td>Plastic</td><td>Hermetic joining</td>

<td>F.</td><td>Paper^{2 5}</td><td>Paper⁵</td><td>Partial connection</td>

<td>G.</td><td>Paper^{2 5}</td><td>Paper⁵</td><td>No linking</td>

<td>H.</td><td>Paper^{2 5}</td><td>Ppaier⁵</td><td>Hermetic joining</td>

Comments ¹ Biaxially oriented polypropylene (BOP) packaging, consisting of a laminate of two BOP layers between which printed material is placed, the outer layer of the package having a melt number greater than the inner layer for hot melting during welding, and the outer layer of acrylic polymer to further assist the bonding process.

₂² Packaging having a paper core laminated with acrylic based varnish forming the outer layer and with hot melted wax forming the inner layer.

³ The paper and plastic sealants each have a stiffness value of 15 Taber Stiffness Units in the longitudinal direction of 15 Taber Stiffness Units and 3 Taber Stiffness Units in the transverse direction as measured as shown below.

⁴ After packaging the freshly made bar of soap, the ends of the wrapping paper were either left unbent (no seam), folded and held together by adhesive tape (partial seam), or folded and held together with enough tape to ensure airtight seam (full seam).

⁵ Paper stiffeners and paper core wrappers were pretreated with Carbendazim as a fungicide.

The above-mentioned stiffness values ​​were determined using a Taber V-5 digital stiffness tester (model 150-D) on ten specimens each measuring 40 mm x 70 mm, five of which were cut in the transverse direction and five in the longitudinal direction6

PL 208 909 B1. Prior to testing, the samples were kept at 23 ° C and 50% humidity for 24 hours. The meaning of Taber stiffness units is described in the TAPPI T489 om-86 standard.

Each of the aforementioned packages and stiffeners was assessed for their resistance to mold growth. The evaluation method was as described below.

Sabouraud dextrose agar was used as a mold growth promoting medium. It consists of mycological peptone (commercially sold by Oxoid Ltd. of England as Oxoid 40) (10 g), dextrose (40 g) and agar (15 g). This mixture is commercially distributed as Oxoid Ltd. in the form of a powder (CM40) or tablets (CM42). When used, it is mixed with 1000 ml of distilled water and kept in an autoclave for 20 minutes at 110 ° C and then cooled to give the growth medium a pH of 5.6.

Small squares of test packaging material were cut using scissors dipped in alcohol, held in a flame, and cooled. The squares were placed right side up and upside down on the surface of a Petri dish flooded with Sabouraud Dextrose Agar using fired alcohol dipped tweezers.

Using a sterile pipette, 0.1 ml mold vaccine (approx. 10 days)⁸ spores in ml) was applied to the center of the square of packaging material. Using a sterile plastic hockey stick, the spores were evenly distributed over the agar surface and the packing material.

The petri dishes were set aside for a week at 2 ° C and the level of fungal growth on the packaging material and agar was assessed by visual inspection.

The following criteria were used for the visual assessment:

- no growth

- slight increase

- a certain point increase

- moderate growth over the entire sample

- serious growth over most of the sample

- complete sprouting of the sample

For comparison purposes, Sabouraud dextrose agar without packaging materials and Sabouraud dextrose agar with preservative-free paper squares were included in the tests. A size of 50 was observed in these plates, while 0 was observed for each of the stiffeners and packages in Examples A to H (no fungus growth).

The results of these tests showed that the use of plastic packaging and stiffeners did not result in any fungus growth, even in the absence of any pretreatment with Carbendazim. In contrast, such pre-treatment is necessary for paper stiffeners and packages.

After packaging freshly made trial soap bars with the packaging systems of Examples AH, the samples were stored at 37 ° C and 70% relative humidity and weighed regularly to determine weight loss (in grams) due to moisture loss. The results obtained are shown in Fig. 1.

As shown, the plastic wrapped samples lost significantly less moisture over the 60 day period than the paper wrapped samples, even though the paper had been coated with acrylic or wax coatings on the corresponding sides.