JPH0651398B2 - Sealed sachet - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a sealed sachet, for example a bag for a single dose of detergent. More specifically, the present invention relates to a sealed sachet containing a cleaning agent.

Background and Prior Art European Patent Application No. 87 dated May 21, 1987, based on priority claim of British Patent Application No. 8612706 dated May 23, 1986
304525.6 (Unilever) discloses a sealed container, especially in the form of a sachet with a heat-sealable liquid-unstable seal. The seal is formed from a mixture of a water-labile adhesive component at a temperature of 40 ° C or less and a heat-sealing component that is insoluble in water at a temperature of 40 ° C or less.

The inventors have surprisingly found that certain homopolymers and copolymers can be used alone to form heat-sealable liquid-unstable seals.

DEFINITION OF THE INVENTION The present invention provides a heat-sealable liquid-labile closure. According to the invention, there is at least one tear seal which has a high mechanical strength in the dry state, but which disintegrates in water especially under the action of mechanical stirring, which seal polymerizes essentially or substantially alone. Provided is a sachet characterized in that it is composed of an N-vinylpyrrolidone polymer containing 0 to 95% by weight of a sex comonomer.

Detailed Description Sealants Sealants are N-vinylpyrrolidone polymers containing from 0 to about 95% by weight of comonomer. Sealant is Poly N
It may be vinylpyrrolidone (hereinafter referred to as PVP) itself or an N-vinylpyrrolidone / comonomer copolymer. The preferred comonomer is vinyl acetate, but there are other suitable comonomers such as butyl acrylate. Vinylpyrrolidone is preferably a polymer of 30-100.
% By weight, more preferably 40 to 100% by weight and particularly preferably 5
It constitutes 0 to 70% by weight. Suitable polymers are Ald-rich
Chemical Company Inc. reference number 19,083-7 N
-Vinylpyrrolidone / vinyl acetate (30/70) copolymer. More preferred polymers are Aldrich Chemical
Reference number 19,084-5 N-vinylpyrrolidone / vinyl acetate (60/40) copolymer manufactured by Company Inc.

The sealant may be in the form of a viscous emulsion that, after being applied to one edge of the surface and dried, forms a flexible coating that does not crack as the surface bends. Such a configuration is particularly useful in embodiments where the surfaces to be sealed together are flexible.
For example, it is possible to manufacture a sachet with a high-speed sachet manufacturing machine. The sealant coating may be a continuous coating or a discontinuous coating.

When applying the sealant mixture in viscous form, a single application is generally sufficient. However, when the viscosity of the mixture is low, it is advantageous to make two applications of each sealant on the wall. The first coating coats the surface, and the second coating forms a layer on the surface. In general, applying a sealant to both surfaces to be sealed provides excellent heat sealing.

The sealant composition is preferably applied to the surface in a conventional roller applicator to form a dry, flexible coating.
This is 170 psi under the pressure of 3 bar with the conventional sachet forming machine.
Heat-seal at 0.5 to 200 ° C for 0.5 seconds. With such a machine, the flexible container of the present invention can be manufactured quickly and easily. Of course, one of ordinary skill in the art will readily appreciate other methods that can be used to apply the sealant and seal the material. The dry adhesive layer formed between the wall and the sealant is sufficient and strong, and the accidental failure of the adhesive layer that can be caused by the action of tensile force is not tearing of the adhesive layer but tearing of the non-heat-sealable material. Preferably occurs.

Dimension 1.5 x when measured with Alwetron ™ tensiometer
The preferred dry bond strength of a 0.5 cm seam is 0.5 N or more, preferably 2 N or more, particularly preferably 5 N or more.
The adhesive strength after immersion is preferably less than 0.4N, particularly preferably less than 0.1N. The wet strength of the adhesive layer is preferably less than 40% of the dry strength, more preferably less than 30% and particularly preferably less than 5%.

Sustained or sequential release is also possible with proper choice of sealant.

Types of Vessel Walls The walls of the sachet are preferably made of non-heat sealable material. The term non-heat-sealable material means a material that does not heat-seal at a temperature above the minimum heat-sealing temperature of the sealant used by 30 ° C.
It is not essential that the walls consist of a non-heat-sealable material, but the temperature, duration and pressure of the sealing process are chosen so that the sachet walls do not adhere directly to each other in large areas without a sealant interlayer. It is important to be done. The sachet is preferably heat sealed, although other sealing methods such as pressure, ultrasonic and radio frequency induction may be used. Generally, a sachet with at least one water-permeable wall (or surface) will be opened more quickly than if all walls were impermeable. The wall can be any shape, but woven cloth,
Flexible materials such as knitted or non-woven fabrics or paper webs or sheets are preferred. The wall material is preferably fibrous, but may be filamentous material, slitted material or perforated material. Suitable fibrous materials are cellulose, cellulose / regenerated cellulose mixtures, polyesters and mixtures thereof.

In a preferred embodiment, the wall is sausage casing paper, viscose / cellulose blend. This material has the advantage over many other papers that it has higher wet strength, especially at elevated temperatures.

The sachet wall preferably has a basis weight of 5 to 100 g / m ² , more preferably 10 to 60 g / m ² , and particularly preferably 15 to 40 g / m ² .

When the permeability of the sachet wall is very high, the contents may leach before the sachet seal is opened. This is a drawback when sustained release of container contents is required,
This problem can be solved by using walls that are less permeable.

The sachet of the present invention is preferably rectangular or square and is formed with four tear seals or one fold and three tear seals. As a rule, it is sufficient to have only one opening seal. Sachets with a plurality of non-opening seals and at least one opening seal are also included within the scope of the invention, in which case pattern coating is required.

The sachet may be manufactured by forming the material in the form of a pouch with a coating on its inner surface. Then the contents are introduced and the sachet is sealed.

The present invention is useful both for single chamber sachets that release their contents very quickly and for multichamber sachets that sequentially release the contents of multiple compartments through the use of multiple seals that open at different times.

According to a preferred embodiment, the sachet of the present invention has two compartments. The compartments have one common unopened seam and three open seams each. Compartments are opened at different times.

Sachet Contents Sachet contents may be of any physical form. The content is preferably powdery. The sachet may contain any substance that is compatible with the materials of construction of the sachet of the present invention. For example, aqueous liquids weaken the seal early and should be avoided. A particularly preferred use of the invention is for domestic laundry, and preferred contents of the products of the invention are premixed detergent compositions, bleaches, bleach precursors, stain removers and fungicides. It will be readily appreciated by those skilled in the art that the use of the product of the invention is not limited to the field of laundry and dishwashing, that other contents can be used in other fields.

EXAMPLES The present invention will be described based on the following non-limiting examples. All coating levels are dry.

The same support in each Example and Comparative Example for comparison,
That is, a sausage casing paper having a basis weight of 21 g / m ² was used.

The sealant was applied to the sample of the support once or twice, and dried after each application. A 150 mm square sachet, each containing 40 g of powder detergent, was formed by heat sealing coated paper.

To test the opening time, the sachet was placed on 2.5 Kg of blended cotton in the drum of a Miele W756W washing machine. The machine was run in a 30 ° C. wash cycle and the time was measured after the time when water entered the machine and drum agitation was initiated. The machine was stopped periodically and the sachet was inspected. The time required to start opening the sachet was recorded. Also, both dry strength and wet strength were measured.

The type of sealant used, the number of sealant applications and the observed results are shown in the table below.

It will be appreciated that the seams obtained with PVP or PVP copolymers have high strength in the dry state but weaken after immersion in water. In contrast, PVA copolymer seams have high strength both before and after soaking.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Douglas Rage Chissi C. H. 2.1 N. N. Upton-By-Chiester, St. James Avenie You 61

Claims (4)

[Claims] 1. At least one tampering seal consisting of a sheet material, which has a high mechanical strength in the dry state, but which collapses under mechanical action in water, said seal being heat-sealable on the sheet material. A sachet formed from a coating layer, said coating layer consisting essentially of an N-vinylpyrrolidone polymer containing 0 to 95% by weight of a polymerizable comonomer. 2. The sachet according to claim 1, wherein the polymerizable comonomer is vinyl acetate. 3. The sachet according to claim 1, wherein the polymerizable comonomer is butyl acrylate. 4. N-vinylpyrrolidone is a polymer of 30 to 10
The sachet according to any one of claims 1 to 3, which constitutes 0% by weight.