NL9300911A - SOLUBLE PACKAGING. - Google Patents

Description

Soluble packaging

The present invention relates to a package containing a liquid chemical or a chemical dissolved or dispersed in a liquid or gel, which is contained in a casing of a water-soluble or water-dispersible material.

Today, most hazardous materials are stored in metal drums or, if smaller quantities are required, in plastic containers.

Hazardous compounds are formulated in a variety of ways. However, it is particularly desirable to handle such compounds when they are in the liquid form. However, there are difficulties and disadvantages in handling liquids. The liquids can be wasted on the ground or leak due to holes in the containers. The containers can also break if subjected to a physical shock.

It is difficult to develop a comprehensive system that is suitable and safe for all those handling the containers and that it is also safe for the environment.

It is known that such compounds may be present in soluble bags or sachets made from films. However, such films can tear and break and therefore cause wastage of the materials they contain. In fact, there are a variety of defects, which may be present in films, leading to film weakness and consequently a potential source of leakage. The presence of air bubbles, of dust particles or other foreign bodies, of gel particles or of thin points on or in the film are all potential weak points. If a film with such a weak point is subjected to a number of manipulations or physical shocks, the film may fail at that point.

The above-mentioned weaknesses of films are present to a greater or lesser extent in certain types of films, depending on their method of preparation. If films are made by casting, small pinholes may be present, but small pieces of gel inclusions are more often present. When films are made by extrusion, more pinholes exist.

The present invention seeks to provide a new chemical container system that is safe to handle.

The invention further seeks to provide a new chemical container system suitable for end users to handle.

The invention further seeks to provide a new chemical container system that reduces the risks of contamination and environmental damage.

In one aspect, the invention seeks to prevent leakage of liquid or dissolved chemicals through pin holes of a film-shaped container system. Although pinholes are generally rare, even the presence of a pinhole in many thousands of containers is sufficient to cause damage as the liquid in the container passes through the pinhole and contaminates the surrounding environment.

Other objects and advantages of the invention will become apparent from the following description.

The container system of the invention is characterized in that a hazardous material in a liquid or gel form is contained in a water-soluble or water-dispersible bag made from a laminated film.

Accordingly, the present invention provides a package containing a hazardous chemical, which is dissolved or dispersed in a liquid or gel, contained in a water-soluble or water-dispersible laminated film.

In this description, the term laminated film means a film made of two or more originally separated layers adhered together. The layers can be bonded together in the laminate by known methods. For example, the layers of the laminate can be joined by pressure, heating, cross-linking, melting, bonding, or any combination thereof. Adhesion of the layers can be achieved by the use of a separate adhesive or if appropriate water.

If suitable water-soluble or water-dispersible layers are used, a particularly suitable way of obtaining a laminated film is by bonding the individual layers, or by using the adhesive PVA (generally of low molecular weight) and / or more easily by means of water.

Since two or more layers are used to produce the laminated film, the likelihood of pin holes appearing in the film is reduced to almost zero. This is because two pinholes in separate layers are unlikely to overlap. Furthermore, the tensile strength of multilayer (e.g., two) films is better than the tensile strength of a corresponding film or the same thickness made from a single layer.

The laminated films used in the invention generally have a thickness of 10 to 250 microns, preferably 15 to 80 microns. The individual layers constituting the laminated films used in the invention are generally each half of these values. When two layers are used, the ratio of thickness of the two layers is generally 0.1 to 10, preferably 0.5 to 2. Bags or sachets made from laminated films of the invention generally have a content of 0.2 to 12 L, preferably from 0.45 to 6 L.

The materials that can be used in the invention are water-soluble or water-dispersible materials, which are not soluble in organic solvents, used to dissolve or disperse the chemicals for which they are used to contain them. Suitable materials include polyethylene oxide or methyl cellulose, but preferably the material consists of or is derived from polyvinyl alcohol, for example, partially or completely alcoholy or hydrolysed, for example 40-99¾. preferably 70-92¾. alcoholy or hydrolysed polyvinyl acetate films.

The layers of the laminated films according to the invention can be made from the same material or from different materials. Films made of layers of different materials can have advantageous properties. For example, an inner layer of a package may be made more resistant to the chemical it contains. In addition, the outer layer of the bag can be selected to have one or more of the following properties: i. dissolve faster (compared to an inner layer or a single layer package) in water, ii. improved mechanical properties, including improved resistance to mechanical damage, iii. improved workability, iv. less sensitivity to relative humidity, e.g. resistance to freezing and / or high temperatures.

One or more of the layers of the laminated film may contain a plasticizer. A suitable plasticizer content in the inner layer can improve the sealing properties of the film and make the film less susceptible to stretching. The film will thus be easier to process on a device and for sealing around a hazardous liquid. A suitable plasticizer content in the outer layer of the container makes the outer surface more flexible and thus more resistant to physical damage from low temperature or shock and movement.

The layers of the laminated film can be made using various techniques, such as extrusion or casting. A laminate made of layers produced by various methods can have favorable properties, including greater flexibility, increased strength and increased resistance to stretching. The increased strength and / or resistance to stretching may be in the film in one direction. The laminated films for use in the present invention are used for the production of packages, which avoid the time consuming and dangerous consequences of known packages, which leak during the filling process and during subsequent handling due to defects in the film.

As already mentioned, the bags (or the container system) can contain either liquids or gels. A preferred feature of the invention is the bags or container system of the invention containing a gel.

According to a particular feature of the invention, the gels are chosen so that one or more of the following features are present: * the resulting gels form a continuous system and / or * the resulting gels have a viscosity of 500 to 50 * 000 centipoise, more preferably 1,000 to 12,000 centipoise (these viscosities are Brookfield viscosities, measured at room temperature with a flat plate viscometer rotating at 20 revolutions per minute), * the gel has a phase difference phi between the controlled shear stress and the shear elongation obtained such that tg (phi) is less than or equal to 1.5, preferably less than or equal to 1.2. Tg (phi) is the tangent of the angle phi (or phase difference). The measurement of phi is performed at room temperature by a rheometer with a flat fixed plate and a rotating cone above this plate such that the angle between them is less than 10 °, preferably 4 °. The cone is rotated by a speed controlled motor; the rotation is sinusoidal, i.e. the torque and angular displacement change as a sine function with time. This angular displacement corresponds to the shear stretch mentioned above; the torque of the controlled speed motor (which effects angular displacement) corresponds to the above-mentioned controlled shear stress, * the gels preferably have a density greater than 1, preferably greater than 1.1, * the gels have a spontaneity ( as defined below) of less than 75, preferably less than 25.

Spontaneity is determined by the following method: a mixture of 1 ml gel with 99 ml water is placed in a 150 ml glass tube (diameter 22 mm) which is closed and inverted 180 ° (upside down) at room temperature. The number of times required to fully disperse the gel is called spontaneity.

By the term continuous system is meant a material that is visually homogeneous, i.e., that it has the visual appearance of only a single physical phase; this does not exclude the possibility that it contains small solid particles dispersed in it, provided that these particles are small enough that they do not form a visible separate physical phase.

It is known that a gel is generally a colloid in which the dispersed phase is combined with the continuous phase to form a viscous jelly-like product; it is also a dispersed system, usually consisting of a high molecular weight compound or aggregate of small particles in very close association with a liquid.

To make a bag, the film must be formed (possibly partially sealed) and then filled with the gel. In general, the gels are able to flow even if it is a slow speed due to the high viscosity. A container used to contain gels cannot be easily emptied due to this high gel viscosity. After filling, the bag must eventually be sealed, generally heat sealed to be closed.

The invention is further illustrated by the following examples.

Example I

A roll film is constructed from two thinner films by lamination: both films are made from an 88% hydrolyzed polyvinyl alcohol (cold water soluble), each 25 microns thick; one has a plasticizer content of 17¾, the other has a plasticizer content of 15%. The two films are laminated together using heat (100 ° C) and pressure to form a film with a thickness of 50 microns.

This film is then used to produce 1L bags containing a solvent based liquid herbicide (mixture of esters of ioxynil and bromoxynil) using so-called form filling methods. The herbicide is a solution in a mixture of aromatic hydrocarbons with 10 carbon atoms as the solvent.

The film is placed on the machine to produce the high plasticizer layer on the outside of the sachets. The film is thus easy to process.

No leaks are observed during the manufacture, handling and transportation of 500 sachets.

Example II

A gel is prepared by stirring 50 ° C of a mixture; active ingredient: 2,4-di- (phenoxybenzoic acid isooctyl ester): 64.8 # solvent: aromatic solvent with a flash point of 65 ° C: 24.2 # surfactant: a mixture of a nonionic / sulfonate as mixed emulsifier 4 # and calcium alkyl benzene sulfonate 1 # gelling agent: a mixture of dioctyl sulfosuccinate salt and sodium benzoate: 6 #

The mixture is stirred and shaken until each component is dissolved or dispersed.

A solution and then a gelation appear during stirring. Gelation is increased during cooling to room temperature (20'C).

The Brookfield viscosity of the gel is 3-000 centipoise. The stability of the emulsion is good in the test described above.

1,100 g of this gel is placed in a 1 L bag made from a PVA film according to the film of Example 1. The bag, which is nearly full (approximately 95 / vol / vol), is heat-sealed poem. The density of both the gel and the bag containing the gel is 1.1.

The bag is dropped to the ground 10 times from a height of 1.2 m. No breaking or leaking is observed.

Another bag, manufactured in the same manner as the above, is being tested for pinhole protection. A needle (diameter: 0.6 mm) is inserted through the bag. A small droplet is observed to form where the needle has been pierced, but this droplet was small enough that it did not fall from the bag and flow past the bag.

Claims (17)

1. Packaging, marked. in that it contains a hazardous non-agri-culture chemically applied chemical which is dissolved or dispersed in a liquid or gel present in a water-soluble or water-dispersible laminated film. Packaging according to claim 1, characterized in that the hazardous chemical is a non-agricultural chemical agent. Packaging according to claim 1 or 2, characterized in that the hazardous non-agrochemical chemical is dissolved or dispersed in a liquid. Packaging according to claim 1 or 2, characterized in that the hazardous non-agrochemical chemical is dissolved or dispersed in a gel. Packaging according to one or more of the preceding claims, characterized in that the laminated film has a thickness of 10 to 250 microns, preferably from 15 to 80 microns. Packaging according to one or more of the preceding claims, characterized in that it has a staple content. agrochemically applied hazardous chemical from 0.2 to 12 L, preferably from 0.45 to 6 L. Packaging according to one or more of the preceding claims, characterized in that the water-soluble or water-dispersible laminated film is not soluble in the liquid or gel used to dissolve or disperse the non-agricultural chemical hazardous chemical dust, Packaging according to one or more of the preceding claims, characterized in that at least one of the layers of the film is selected from polyethylene oxide, methyl cellulose or partial or fully alcoholized or hydrolysed polyvinyl acetate. Packaging according to claim 8, characterized in that the at least one layer is 40-99 $. preferably "] is 0- $ 2% alcoholysed or hydrolyzed polyvinyl acetate. Packaging according to one or more of the preceding claims, characterized in that at least two of the layers of the laminated film are made of the same material. Packaging according to one or more of claims 1 ~ 9. with the attribute. that at least two of the layers of the laminated film are made of a different material. Packaging according to one or more of the preceding claims, characterized in that the laminated film mainly consists of two layers. Packaging according to claim 12, characterized in that the ratio of the thickness of the two layers is 0.1 to 10, preferably 0.5 to 2. Packaging according to any one of claims 4-13, characterized in. that the gel has a viscosity of 500 to 50,000 centipoise, preferably 1,000 to 12,000 centipoise. Packaging according to any one of claims 4 to 14, characterized in that. that the gel has a phase difference phi between the controlled shear stress and the shear strain obtained, such that tg (phi) is less than or equal to 1.5, preferably less than or equal to 1.2. Packaging according to any one of claims 4-15, characterized in that the gel has a spontaneity less than 75, preferably less than 25. A method of manufacturing a package according to any of the preceding claims, characterized in that two or more layers are laminated together by printing, heating, cross-linking, melting or by water to obtain the laminated film .