NL192873C - Soluble packaging. - Google Patents

Description

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Soluble packaging

The present invention relates to a package containing a hazardous chemical which is dissolved or dispersed in a liquid or gel present in a water-soluble or water-dispersible laminated film.

Such a package is known from Japanese patent application 02 / 108,534. This literature describes a package which is soluble in cold water and which comprises at least one layer based on polyvinyl alcohol resin (PVA) and at least one layer based on polyethylene oxide resin (PEO). The film is used as a packaging material for solid materials such as laundry, powders, solid farming chemicals and the like. The film according to Japanese patent application 02 / 108,534 has a sufficient strength, is resistant to acid and base, can be closed under the influence of heat and is not sticky and is soluble in cold water.

European patent application 347.220 relates to a packaging material consisting of a water-soluble or water-dispersible film, wherein the film can be made of polyvinyl acetate, which is hydrolysed from 70 to 92% and the film has a thickness of 10 to 500 µ, for example 30 μπι, can own.

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

Hazardous compounds, especially agricultural chemical compounds, have been formulated in a variety of ways. However, it is especially desirable for farmers to handle such compounds when they are in the liquid form. This facilitates spreading out such connections. 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 for farmers and is safe for all 25 who handle the containers and is also safe for the environment.

It is known that agricultural chemicals can be present in soluble bags or sachets made from films. However, such films can crack and break and therefore cause wastage of the agrochemicals 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. This is a particular problem for the agrochemical industry, where containers can be subjected to rough and unsafe handling by users.

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 novel agrochemical container system 40 that is safe to handle.

The invention further seeks to provide a new agrochemical container system suitable for end users, for example farmers to handle.

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

In one aspect, the invention seeks to avoid leakage of liquid or dissolved chemicals through pores of a film-shaped container system. Although pores are generally rare, even the presence of a pore in many thousands of containers is sufficient to cause damage, as the liquid in the container passes through the pore 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.

According to a preferred feature of the invention, the hazardous compounds are agricultural chemicals, for example pesticides or plant protection agents or plant growth control agents.

The present invention consequently 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 10 simply by means of water.

Since two or more layers are used for the production of the laminated film, the likelihood of pinholes occurring 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 multi-layer (eg two) films is better than the tensile strength of a corresponding film or the same thickness, which is made of a single layer.

The laminated films used in the invention generally have a thickness of from 10 to 250 µm, preferably from 15 to 80 µm. 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 from 0.2 to 12 I, preferably from 0.45 to 6 I.

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, eg partially or fully hydrolyzed, eg 40-99%, preferably 70-92%, hydrolyzed 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 rendered more resistant to the agrochemical it contains. In addition, the outer layer of the bag can be selected to have one or more of the following properties: i. quickly dissolve (compared to an inner layer or a single layer package) in water, ii. good mechanical properties, including good resistance to mechanical damage, iii. good workability, iv. low 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-coated 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 coated 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 55 of the invention containing a gel.

According to a particular feature of the invention, the gels are selected so that one or more of the following features are present: 3 192873 - 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) 5 - 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 room temperature measurement of phi is carried out by means of 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 means of 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 regulated speed motor (which effects the angular displacement) corresponds to the above-mentioned controlled shear stress - the gels preferably have a density greater than 1, preferably greater than 1.1 15 - the gels have a spontaneity (such as defined below) of less than 75, preferably less than 25.

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

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 viscosity of the gel (this is one reason why the gels have hitherto not been used in agriculture). 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 (soluble in cold water), each 40 microns thick; one has a plasticizer content of 17%, 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 μπ.

This film is then used to produce bags of 11 containing a solvent-based liquid herbicide (mixture of esters of ioxynil and bromoxynil) using 45 ”form-and-fill” 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 at 50 ° C a mixture: active ingredient: 2,4-di- (phenoxybezoic acid isooctyl ester): 64.8% solvent: aromatic solvent with a flash point of 65 ° C: 55 24.2% surfactant: a mixture of a nonionic / sulfonate mixed emulsifier 4% and calcium alkylbenzene sulfonate 1%

Claims (4)

19ΖΒΛ3 4 gelling agent: mixture of dioctylsulfosuccinate salt and sodium benzonate: 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). 5 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 are placed in a 1 L bag made from a PVA film according to the film of Example I. The bag, which is nearly full (about 95% vol / vol), is heat sealed. The density of both the gel and the bag containing the gel is 1.1. 10 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 off the bag and flow past the bag. Packaging containing a hazardous chemical, which is dissolved or dispersed in a liquid or gel, present in a water-soluble or water-dispersible laminated film, characterized in that the film consists of two or more layers made of the same material.