DE2500169A1 - MELT EXTRUDABLE COLD WATER SOLUBLE FILMS - Google Patents

Description

Many common chemicals are made in powder form and placed on the market, but slurried, dispersed or dissolved in water before use. Examples of this Chemicals are pesticides (especially insecticides, herbicides, nematicides, fungicides and the like), which are available as aqueous spray preparations are used, detergents (e.g. detergents for farms, Bleach and alkaline cleaners) 'which are dissolved in the washing water process aids (such as carbon black and activated carbon), which can be suspended in water, as well as pigments and dyes, which are dissolved or dispersed.

Various problems arise when using the aforementioned products. One problem is that the consumer and its immediate vicinity from the chemical substance in Be drawn to kiteboarding. When opening a finely ground Pack containing material, when measuring a certain amount of the material and when transferring the measured

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measured amount from the package to the device in which the substance is brought into contact with water, dust can be raised with which the consumer comes into contact and which pollutes the environment. In the case of pesticide dust, the Risk of irritation to the eyes and the mucous membranes of the nose and throat. Herbicide dusts can damage plants that are in the area where the packs are opened. Dusts from pigments or activated carbon cause serious problems Cleaning problems.

The second problem associated with the use of common powdered chemicals is dimensional accuracy. One Excessive dosage of the expensive products is of course uneconomical. An unconcentrated herbicide solution does not allow effective control of the undesired plant species while if too concentrated a solution of the same substance is used, there is a risk that some crops will be at the same time as the weeds damaged v / earth. It is often extremely difficult to accurately measure substances that have compacted and / or have become lumpy, as well as powdery materials that are exposed to the wind.

Ultimately, the consumer after using the chemical faced with the problem of getting rid of the empty package. This can contain residues of substances, which raise pollution problems associated with potential threats to humans and damage to plants and animals or are just uncomfortable and unsightly.

The previously available water-soluble foils or films (hereinafter the term "foils" is always used) and packs show deficiencies in one or more relationships, such as:

a) Many films characterized as "water-soluble" dissolve slowly or incompletely in cold water, resulting in formation of gel-like particles. These particles tend to be deposited on boiler walls, pipes, pumps and valves,

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resulting in an inhibition or prevention of the flow through Sieben und Dü3en leads. The melt extrudable films of the invention are in water at a temperature of only 4 ° C quickly and completely soluble. And do not form gel-like Particles of undissolved or partially dissolved polymer.

b) Many of the compositions used to make such films have physical properties that make them large, expensive, and energy consuming and technologically complex devices for film production, such as solvent casting (or knife or tape casting) are necessary. Typical Solvent G. casting process consists in dissolving the mass in a suitable solvent (e.g. water) »spraying the solution onto a conveyor belt or pouring and spreading there and drying (generally by evaporating off the excess solvent) and stripping the dried film off the conveyor belt and then cuts it to size or brings it into the desired shape. The technological complexity of this way of working is just as evident as the fact that one for so many Process stages designed plant extensive and costly would be. With regard to electricity costs and supply problems In the energy sector, it may be even more important that drying is by evaporation A process stage containing large amounts of water high energy consumption is required.

In the aforementioned production methods, use is preferably made of melt extrusion. For melt extrusion Compared to the aqueous pouring method, they are extremely small, cheap, technologically simple and use very little energy Devices needed.

c) Many conventional water-soluble films have physical ones Properties (e.g. yield point, tear strength, toughness, flexibility) on the basis of which the film is not suitable for packaging quantities of powdery substances in the range of 0.227 to 1.5 kg (0.5 to 10 lbs). Such

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Films cannot be used for automatic packaging machines either.

d) The components of many conventional water-soluble packaging films are numerous, difficult to obtain, and / or expensive.

e) The prior art includes, for example, Japanese Patent Publication No. 28 588/69, US Patents 3 37 ¹ J 195 and 3 13 229, and British Patent

1,330

Japanese Patent Publication No. 28,588/69 teaches that a melt-extrudable water-soluble film is made of a polyvinyl alcohol can be made with a viscosity of 18 cps jl x 2 cps and one of numerous polyols. It gets persistent on Restrictions regarding expandability and rapid temperature indicated. Many of the films in question do not dissolve quickly in water, and many sweat out and sweat during melt extrusion many are not suitable as water-soluble packaging films.

US Pat. No. 3,374,195 describes one cast from an aqueous medium Foil that is soluble in hot or cold water. The film is made of polyvinyl alcohol and a combination of two plasticizers, d. H. a polyethylene glycol with a molecular weight of 200 to 600 and hydroxypropyl glycerine. the U.S. Patent does not teach that the composition is melt extrudable while using kydroxypropyl glycerine as a necessary co-plasticizer referred to as.

In British Patent 1,330 7 ^ 5 there is one made of aqueous wedium In some cases, which are soluble in hot or cold water is. The film consists of polyvinyl alcohol and a combination of polyvinylpyrrolidone and an - optional - plasticizer. The GB-PS does not teach that the composition is melt extrudable while polyvinylpyrrolidone is said to be a necessary ingredient.

According to the invention it has been found that compositions

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which consists essentially of 5 to 20 parts by weight of a polyethylene glycol with an average molecular weight (weight average) of about 325 to 550 in 100 parts by weight of a polyvinyl alcohol, which is saponified to 85 to 90% and a viscosity of 3 to 10 cps (measured on a ^ percent aqueous Solution at 20 ⁰ C), consist, according to the conventional melt extrusion method, films with a thickness of 0.0127 to 0.25 * 1 (0.5 to 10 mils) can be produced from the same composition, which can be produced quickly and completely in cold water solve and can be used as packaging films for automatic packaging devices.

Suitable compositions can be made from commercially available polyvinyl alcohol and polyethylene glycol, each of which is relatively inexpensive.

The films can be used for packaging powdery substances. The film package containing the powdery material can can be entered directly in V / ater, eliminating the problems of consumer contact, the exact dimensions and the disposal of the container can be solved.

The films also pass the standard tests explained in the description.

The invention will now be explained in more detail.

"Films" are to be understood here as single-layer structures (excluding laminates). Is suitable only polyvinyl alcohol having low molecular weight (viscosity from about 3 to 10 cps, measured in a 4 per cent aqueous solution at 20 ⁰ C after the Hoppler falling ball method (ASTM-D 13 ^ 3-56, Part 8, 1958, page ^ 86). Polyvinyl alcohol grades with medium or high molecular weight result in films which are difficult to extrude and / or which fail at least one of the standard tests. In addition, the polyvinyl alcohol only needs to be partially (ie 85 to 90 %) saponified. The polyvinyl alcohol can be produced from polyvinyl acetate by saponification, at which the

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desired percentage of the acetate groups is replaced by hydroxyl groups.

As far as glycols are concerned, only polyethylene glycol with an average molecular weight (weight average) of about is suitable 325 to 550. Polyethylene glycols with lower or higher molecular weights, such as the commercial grades PEG 3OO and PEG 600, lead to products which in one or more of the standard tests fail. Similarly, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polypropylene glycol and glycerin also result unsatisfactory compositions.

To identify the for the compositions according to the invention and films of polyethylene glycol to be used, the average degree of polymerization is used as an alternative. That is, at the characterization of a polyethylene glycol of the following general formula

HO (CH ₂ CH ₂ O) _n H

η means the degree of polymerization. Regardless of whether the polyethylene glycol is characterized by the weight average molecular weight or the degree of polymerisation, means the citation of a certain molecular weight or degree of polymerization, that substances are included, which are predominantly but not necessarily have the specified average molecular weight or the specific degree of polymerization. For example small amounts of lower or higher molecular weight materials may be present. A typical molecular

weight distribution of polyethylene glycols is given for Carbowax 400 (Union Carbide) in the report "Carbowax Polyethylene Glycols", Page 22, F-4772G, 1 / 72-10 M cited. Polyethylene glycols with average degrees of polymerisation from 7 to 12 are useful in the present invention Compositions useful.

The correct proportions of the two components must be observed will. When using less than 5 parts by weight of the polyethylene glycol per 100 parts of the partially saponified Polyvinyl alcohol gives you a composition which is not

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is more rapidly soluble in cold water, melt-extrude slowly leaves and gives off a brittle film. When using more than 20 parts by weight of the polyethylene glycol per 100 parts of the partially saponified polyvinyl alcohols, the result is a composition which has a satisfactory extrusion rate possesses, but is subject to exudation to an intolerable degree. The latter means that the polyethylene glycol is at least partially repelled by the polyvinyl alcohol, whereby a slimy coating forms on the film.

The aforementioned films can be produced on an industrial scale with the aid of conventional melt extrusion devices, as are customary used in the production of polyethylene, polypropylene or polyvinyl chloride films. The novel compositions of the invention, which are in the form of powders, granules or pellets, are melted by a Slit or an annular opening extruded, quenched with air and then deep-drawn and / or blown into a thin film. The film can be stretched in this way oriented state.

The preferred embodiments of the present invention are explained below.

The most preferred plasticizers because of their property as candy products are polyethylene glycols with an average molecular weight of 380 to 12 O, e.g. B. Carbowax 400 (Union Carbide, New York). Other polyethylene glycols regarded as equivalent to Carbowax 400 are Poly G ^R 400 (Olin Chemicals, Stamford, Connecticut) and GafanorTS400 (GAF Corporation, New York).

The preferred polyvinyl alcohol has an average degree of saponification of 87.7 to 89.7 % and a viscosity of 4 to 6 cps (measured on a 4 percent aqueous solution at ²⁰ ° C.); The commercial product Elvanol 51-05 (EI du Pont de Nemours and Company, Wilmington, Delaware) is particularly preferred.

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Other polyvinyl alcohols regarded as equivalent to Elvanol 51-05 are Gohsenol ^R GL-05 (Nippon Gohsei) and Gelvatol ^R 20-30 (Monsanto).

The preferred relative proportions of the two main ingredients are 12 to 17 parts by weight of the polyethylene glycol in 100 parts by weight of polyvinyl alcohol, in particular 15 parts by weight of polyethylene glycol per 100 parts by weight of polyvinyl alcohol.

Small amounts (^ 5 parts by weight, preferably 0.5 to 1 part by weight, in each case based on 100 parts by weight of polyvinyl alcohol) usually used for cellulose, vinyl or polyolefin films Auxiliary materials used, v; ie mold release agents, antiblocking agents and lubricants, can be added either before or after extrusion, provided that water solubility or other primary properties of the resulting film are not appreciably impaired. You can take the train for example Dust with talc when winding up before storage or packaging. The following substances are preferred to the approach incorporated prior to extrusion. You can z. B. inorganic fillers

use substances such as clays, silicon dioxide [e.g. B. Cab-o-sil L-5 (0.05 micron) or M-5 (0.012 micron), Cabot Corp., Boston, Mass.), Aluminum oxide, and silicates such as sodium silicate or lithium polysilicate (Polysilicate 85, EI du Pont de Nemours and Company, Wilmington, Delaware./. Examples of suitable organic substances are (1) long-chain fatty acids, alcohols, amides or salts, e.g. stearic acid, stearyl alcohol, erucamide and magnesium stearate, (2) waxes, (3) partially oxidized low molecular weight polyethylene (e.g. XL-223 ~ American Hoechst) and (4) silicones, e.g., dimethyl silicones.

In addition, small amounts of water-soluble polymers, some of which with the polyvinyl alcohols according to the invention, can be used are compatible (e.g. polyethylene oxides with a molecular weight of at least 600), with advantage as co-plasticizers are added, provided that the proportion of the partially compatible polymer is not more than 2 parts by weight (based on

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100 parts by weight of polyvinyl alcohol). Examples of such partially compatible polymers are polyethylene glycols or polyethylene oxides with molecular weights of at least 600 and polypropylene glycols or polypropylene oxide / ethylene oxide copolymers with a molecular weight of at least 400. Polyethylene oxides with molecular weights from 500,000 to 1,000,000 are most preferred.

The atmospheric moisture acts as a co-plasticizer, which makes the film tough. When the films according to the invention are produced by melt extrusion, the operating temperatures of the device mean that the film contains little or no water when it is first formed. However, when the film leaves the extrusion apparatus, it comes into contact and equilibrium with the surrounding atmosphere, which usually has a relative humidity of 25 to 70%. The preferred moisture content of the film (based on the dry material) before cutting is 4 to 5% &> 5 to 7 $ are preferred for the film ready for packaging purposes. The preferred range of relative humidity for automatic packaging is 25 to 65 % > especially 35 to 55%.

The films according to the invention are preferably produced by blow extrusion produced, which is particularly useful because a biaxial orientation is achieved in this stretching process leaves. Due to the orientation, the toughness of the film increases, which z. B. in the impact strength and, tear strength affects.

The films of the invention are soluble in cold water, ie v / ater of 4 ⁰ C (40 ° F) as it is available for taking place in large scale agricultural operations in spring or autumn, rapidly (within less than 1 minute per 0.025 ¹ J mm thickness) and complete. Of course, the rate of dissolution is faster in warmer water. The films according to the invention have excellent properties in terms of processability in automatic packaging devices and handling

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of the filled packs. The extruded films are particularly suitable for packaging powdery substances on conventional packaging lines, e.g. B. in vertical generation and Filling machines in which heat-sealed "pillow packs" are produced will.

The cold water-soluble packaging films of the invention are particularly suitable for packaging powdery, dusty, harmful, irritant and / or toxic substances which, in water or mixed solvents, contain water as a component contain, dispersed, slurried, suspended or dissolved Need to become. The films can therefore be used specifically for the packaging of agricultural chemicals. The invention Films can also be used for packaging liquid substances, e.g. B. of liquid formulations for agricultural purposes, which are to be dispersed in water and whose base is immiscible with water and with polyethylene glycol immiscible oils and hydrocarbons such as cyclohexane, mineral oil and kerosene. Examples of materials which can be successfully packaged in measured quantities in containers produced from the films according to the invention Pesticides (such as insecticides, herbicides, nematicides, and fungicides), detergents (such as laundry detergents, detergents, and caustic products), chemical process auxiliaries (such as catalysts for Polymerizations, carbon black, activated carbon, pigments and dyes), foods and food additives. Other uses consist in taking measured amounts of incompatible materials such as flour and oil, the fungicides Benomyl and Maneb and the like in separate water-soluble film packs and these separate packs with a single one wrapped in moisture-proof packaging material. When using separate water-soluble packages containing the pre-measured amount of the additive or chemical, simultaneously incorporated into the liquid in a suitable mixing device; this prevents premature implementation or Blending and eliminating sources of dimensional error.

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To protect the water-soluble packaging during storage, when A moisture-resistant outer cover must be available for transport and handling to prevent damage from atmospheric agents Water, such as high humidity, rain and dew, as well as accidental contact with water by splashing or from wet hands. This moisture-proof outer cover can either be used for individual packs or groups of Packs may be provided as is most appropriate for the particular case. You can use moisture-proof cardboard. When the outer cover is removed, the soluble packs must of course be protected from contact with water or can be used immediately.

Suitable materials for the outer shell are polyolefin films, such as polyethylene or polypropylene, Kraft paper moisture-proofed with polyethylene, moisture-proof Cellophane, glassine (thin, transparent, very flexible paper), metal foils, polyester, polyvinyl chloride, polyvinylidene chloride and combinations of these materials, e.g. B. in the form of laminates. The choice of the outer shell is based on economic considerations and the required strength.

The compositions of the present invention thus have the following Combination of properties:

1) They are easy to use by conventional melt extrusion methods can be processed into foils without the need for water and without exudation; and

2) the melt-extruded films (a) can during extrusion be oriented or aligned so that different degrees of toughness are achieved, (b) are in cold water rapidly and completely soluble and (c) can be used in automatic packaging devices.

The following examples and test methods are intended to explain the invention in more detail. All parts and percentages relate to the weight, unless otherwise stated.

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Standard tests
I) Compatibility of the components of the composition

This test is used to test the exudation of the plasticizer from a film under ambient conditions (ie 25 ° C., 25 to 70 % relative humidity).

The test is expediently carried out on a film which has been melt-extruded or poured from solution as follows:

About 30 g of an aqueous stock solution (10 to 10 percent) of the desired polyvinyl alcohol are stirred with the desired amount of the undiluted plasticizer at room temperature with a high-speed disk stirrer until the mixture appears visually homogeneous. Steam heating can be used briefly to improve mixing. The resulting casting solution is poured onto a 1.91 cm Lucite plate (Lucite = acrylate or methacrylate resin) and wiped off with the aid of a doctor blade, ^{leaving such a gap that, after drying overnight under ambient conditions, a 0.025 1} J to 0.0508 1 to 2 mils (mm) thick film can be peeled off the plate.

Exudation occurs to an undesirable extent where there is a visual inspection of a film after the Wipe over with a cotton cloth over the surface of which shows a layer of softener.

II) Cold Water Solubility Rate

Both of the following tests are carried out on a film which has previously been exposed to 25 to 75 % rel. Moisture has been brought into equilibrium.

A) Spray tank cold water solubility rate

This test generally determines the spray tank conditions simulated on the field. The pesticide package is dropped into cold water with gentle agitation, with the pesticide being removed

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is dispersed. The aqueous dispersion obtained (or Solution) is pumped through a fine sieve. The screen is then quickly covered with a fine mist of developing dye solution sprayed and examined for residual gels or pieces of the slide.

In specific regard, a 18.9 liter Stahlsprühtank or nebulizer (3O, 5 cm diameter, 55.9 cm Köhe) is isolated, filled with tap water and cooled to ⁰ ^ C. The water is pumped through a valve at the bottom of the tank, a centrifugal pump (Eastern Industries, Model D6, Type 215 »1550 rpm, 1 to 3 A, 0.0338 PS = I / 30 HP) and circulated back to the top of the tank. A heat-sealed "pillow pack" made from the film to be tested and containing a powdery pesticide is dropped into the tank. At the same time, a stopwatch is started and the "break-up time ^11" (which is reached when the water first penetrates the class pack and touches the pesticide) and the "release time" (which is reached when the pesticide disperses and begins to peel off from the rest of the pack; generally the pesticide drips off the floating pack).

A steel paddle stirrer (7.62 cm wide, 1.91 cm high and 0.32 cm thick) is operated at a speed of 300 rpm. Every Minute, a sample of the stream entering the tank is tested for gel components by passing it through an immediately 50 mesh sieve suspended above the tank (with openings of 0.297 now and a wire diameter of 0.215 mm) leads. As soon as no further gel is found during this examination, the time is recorded. This time is as a valid indication of the complete dissolution, if after direct passage of the entire tank contents through the sieve and developing the sieve by spraying with a saturated aqueous solution of FD&C blue No. 1 no gel is found. The absence of

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if the entire experiment is completed within 10 minutes, it is to be regarded as satisfactory.

B) Foil washer cold was serious Ii chkeitsf-eschv.'indirkeit

This test is a rapid laboratory test that simulates the spray tank cold water solubility rate test discussed above. The size of a sheet of film 3.18 cm in diameter and 0.025 ^ to 0.051 in thickness (1 to 2 mils) is now determined with the aid of a micrometer to a value of 0.0025 ^ ram (0.1 mil). They place a rubber seal, which by punching a hole (diameter 2.5 cm ^) in a rubber disc (diameter 3> ^J t9 cm, thickness 0.16 cm) was formed on the film disk and clamps it with the aid of two as a frame functioning flat metal rings, of which the smaller has a hole with a diameter of 2.5 ^ cm, close together. The frame with the foil attached is placed on a small tripod and lead shot (diameter 2.00 to 2.38 mm) is placed on the foil disc. The entire equipment is then lowered into a 1 liter beaker (the tripod is half the height of the beaker), which contains 900 ml of tap water at ¹ I ⁰ C, and a stopwatch is immediately started. The 'sinking time' is determined (which is reached when the shot breaks through the foil disk) and stirring begins with a 5.08 cm magnetic stir bar at 75 rpm. As soon as the visual examination reveals no further gel or pieces of the foil, make a note This time is to be regarded as a sound indication of complete dissolution if no gel is found after the solution has been poured through a sieve and developed as in the spray tank test. values of 1 min / 0.0254 mm (1 min / mil) or less are considered satisfactory.

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A ·

Αϊ

III) Melt Extrudability 2500169

A) The tester used in this test is a plastometer (Model C, F.F.Slocomb Corp., Wilmington, Delaware), the one with a mouthpiece with a length of 0.8 cm and is equipped with a diameter of 0.2 cm. The piston and weight make up 100 and Ί900 g, respectively.

0.5 to 1 g of the film material expediently present in the form of film strips (film from test I cast from aqueous solution) is added to the ^{cylinder preheated to 210 °} C. and the piston is pushed down by hand in order to compress the film. It is also possible to use starting materials in the form of granules or pellets; in this case, however, longer preheating times are required. After putting the muzzle with a stopper

Teflon (polytetrafluoroethylene) has closed, the film material to be tested is allowed to preheat for about 7 minutes. Then remove the stopper and puts the weight on the piston. As soon as the extrusion of a strand or rod of the molten polymer begins ^ cut the strand with a spatula and start a stopwatch at the same time.

The strand that then emerges is removed from a polished plate placed 7.62 cm below the mouth stainless steel until the speed visibly slows down or until M minutes have passed are. Then the strand is cut and the stopwatch is stopped. The extrudate is weighed and calculated an "extrudability index" in g / 10 min.

When catching up one observes the exudation or the Exhaust gas development. The extrudate is on the exudate or melt cracks on its surface, clarity, color, Tested toughness and bubbles. The exudation or the volatilization can also spread through the occurrence a plasticizer veil on the steel plate.

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Assemblies are considered to be satisfactory with an extrudability index of more than 1, which is clear, smooth, tough (as can be seen from fracture-free bending of the stick proves to be on itself) and have no blisters or exudations.

B) The self-compatibility of the melt-extruded composition is determined by storage for ^ hours at 70 % rel. Humidity determined. Sweaty or wet surfaces on the extrudate are signs of unwanted exudation at high rel. Humidity.

IV) Packaging and handling

A) Nitrogen bending test

To determine whether the film is completely dry immediately after exiting a melt extruder can be handled without breaking, one hangs about 2.5 * 4 χ 10.2 cm measuring cast film strips overnight at 25 ° C. in a drying cabinet flushed with nitrogen. Afterward fold the strips in the short direction twice along the same line. The slide is found to be satisfactory considered if it does not break and no cracking occurs.

B) heat sealability

The processability of a film ( equilibrated at 27 to 70% relative humidity for 2 hours) to form packs is assessed on an automatic packaging machine with the aid of an impulse heat sealer (Sentinel Pacemaker Impulse Heat Sealer Model 12 TP, Packaging Industries, Hyannis, Massachusetts) . The movable upper clamp is equipped with a 0.32 cm band made of nichrome (alloy of 60 % nickel, 24 % iron, 16 % chromium and 0.1 % carbon). Both the upper and lower clamps are lined with Teflon-impregnated glass fabric.

A double strip (2.5 ^ cm χ 10.2 cm) of foil

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having a thickness of 0.025 ¹ to 0.051 J irjn (1 to 2 mils) is bonded under a pressure of 2.11 kg / cm with a pulse duration of 1 second or less hot. The film is satisfactory if it does not burn through and tear when attempting to peel the seal.

C) Package drop test

This test measures the behavior of a 226.8 g (8 ounce) package in storage and rough handling during of transport is simulated.

Lead shot (3.36 mm diameter, * 15 g) is packaged in a package (5.08 χ 5.08 cm when laid flat), which is made from a water-soluble film with a thickness of 0.0381 to 0.0508 mm (1.5 up to 2 mils) is produced, heat sealed. The package is at 50 to 70 % rel. Moisture equilibrated (-5 hours) and then heat sealed in a moisture resistant outer wrap made of 0.089 now (3.5 mils) thick polyethylene / aluminum foil / polyethylene / kraft paper laminate. The wrapped pack is brought to equilibrium at 0 ° C (- ^ 15 hours) and then quickly dropped onto a tiled floor from a height of 1.22 m. Water-soluble packages that remain intact pass the test.

V) auxiliary packaging tests

A) tensile properties .

The tensile properties and the percentage elongation are measured on foil strips measuring 2.5 cm 5.08 cm with the help of on an Instron tester at a feed rate of 5.08 cm / min.

B) bending under load

The flexural strength under load is determined after conditioning a 10.2 cm χ 17.8 cm film at a given rel. Humidity determined. 2.5 ¹ ½ cm

Λ "

wide strips are made along each of 17> 8 cm Edges between two parallel, 1.27 cm apart, in the same plane clamped in gumraia-lined clamps. The unrestrained width (508 cm) of the film forms a U-shape between the terminals. The entire assembly is left in the common plane of the clamps at 60 rpm Rotate the axis, which is in the plane in the 10.2 cm direction of the film and through the middle of the closed Clamps through. A clamp is fixed. The second clamp (weight 681 g) is arranged in such a way that that it slides freely from the fixed clamp while maintaining the parallelism and the 1.27 cm distance and only is stressed by the film subjected to the test. Thus, the movable clamp moves every half Rotation of the assembly relative to the fixed clamp, eliminating the slack in the film test specimen and creates several diagonal and parallel kinks in the film extending from clamp to clamp. When the level the clamp is vertical, the film is loaded with 681 g. The sliding clamp secures the slide every half revolution (i.e. when the clamp slides from one extreme position to the other) an initial one Impact load imposed. Each half turn is counted as a load-bend cycle. When the test film breaks, the test is aborted, allowing the movable clamp to operate a switch through which the current causing the rotation of the assembly is interrupted.

C) slip test

One determines the ease of sliding the extruded films over rigid surfaces, for example over a shaped ring of a vertical generation and full packaging machine, by measuring the coefficient of kinetic friction (C.O.F.) of the film. A strip of the Slide onto a film at a speed of 15.2 cm / sec.

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powered platform. A pressure roller with a weight of 200 g is placed on the foil and connected to a dynamometer. One determines the dynamic average force. The C.0.P. value is the result of the weight of the pressure roller divided force; CO.F. values of :? 0.3 are satisfactory (Coefficient of Friction Tester D-1005, Kay.eness, Inc.).

example 1

Production of a powdery starting material for the melt ex-

trusion

A 566 liter ribbon mixer is charged with 204 kg of a suitable one Polyvinyl alcohol. The desired amount of a suitable polyethylene glycol is then injected within 1 to 1.5 hours (undiluted or as an aqueous solution) into the mixer. By adding 5 to 10 parts by weight of water per 100 parts of polyvinyl alcohol a material with better free flow is obtained.

Example 2 Flat shape; Single screw extrusion

According to Example 1, two powdery starting materials are produced with the following recipes:

a) O, 5 tuid 10 parts by weight water 10 parts by weight of Carbowax ^R l "00,100 parts by weight Elvanol 51-05 ^R

b) 10 parts by weight of water

■ D

15 parts by weight Carbowax ¹ 100 parts by weight Gohsenol ^R GL-05

(Nippon Gohsei, cf. "Polyvinyl alcohol", Finch, 1973, John Wiley & Sons, pages 18 to 21)

The batches are fed into a Wayne 1.91 cm single screw extruder, which is equipped with a coat hanger flat shape that

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a two-inch long shallow slot with a ?: O, f62 im
(30 mils) wide gap. The cylinder temperatures
be in the range of 170 to 24O ⁰ C (pressures varies from 35.2 to 70.4 kg / cn ^ wherein the film can be extruded well. The
extruded films are clean, shiny, almost colorless and almost gel-free. There are no blisters or signs of exudation
ascertain. ^{The films can easily be thermoformed (stretched) to a thickness of 0.025 1} mm (1 mil) with the aid of a drive belt.

The films produced in this way pass all of the standard tests described above without difficulty. Table I.
shows the tensile properties of the specified rel. Moisture equilibrated and tested foils.

Table

Together rel. Moisture fu _{+ G} FES _{yield point} ⁺ _De hnung, reduction ACTION ACTION ^ö t

(a) 35 5 * 2.9 2.0 170 (a) 50 22nd 2.1 2.1 310 (b) 35 76 3.1 1.8 23Ο (b) 50 21 2.1 » 2.5 385 + in kg / mm

Example 3 Twin-screw extrusion of a powdery starting material

According to Example 1, several powdery starting materials with the compositions shown in Table II are prepared. The starting materials are fed into a twin-screw melt extruder (Packaging Industries, Inc., Hyannis, Mass.), Which has an L / D ratio of 16: 1, an opening in the middle and a 66 cm long flat Pormschlitz with a 0.127 mm (5 mils)
has a wide gap. At 175 to 200 ^° C., a colorless, clear, exudation-free film is driven around chrome-plated

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Quenching rollers (from room temperature or vractergelcooled) wound, clamped between rubber rollers and by varying the extrusion and winding speed to different Pulled thick (0.0127 to 0.0762 mm; 0.5 to 3 mils). One achieves Extrusion rates of about 27 kg / hour. (according to the capacity of the extruder) at a screw speed of 55 rpm, a winding speed of Ί2.7 m / min, and Thicknesses from 0.0127 to 0.38 mm (0.5 to 1.5 mils).

The films produced in the manner described pass the standard tests I, II, III and IV without difficulty. Table II shows the properties of the specified rel. Humidities Balanced and tested foils.

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Tabel

II

Film extruded with the help of a twin-screw extruder with a flat shape

cn o co

FoIienzu- |
composition Weight rel. Moduli MD / TD , 4/2 , 4 6) 4/2 , 4 Expansion number of Gkrit-Itei- foil spray tank 0.30 0.3 sink ^ 0.6 fraction ³ ^ 100 share Damp , 2/2 , 2 2/2 , 2 At a- exercise windshield - cold water - 0.28 ^υ .ν 0.3 / mil-1.5 peel ^G ew.- Carbo-
wax ^R 400 ££ # , 9/1 , 9 9/1 , 9 sturdy
-Bending-
cycles koefH- -V'fesser- soluble-
efficient (min)
speed (min) 0.2 5 , 1 complete 5-complete share
PVA 10 20th Zugf e- es
stigerr , 0/2 , 2 0/2 , 2 95/34 0.26 GL-05 15th 20th , 1/1 , 5 0/1 , 0 180/57 1 ^ 51-05 10 35 13/17 , 3/1 , 2 8/0 , 3 283/284 162/182 GL-05 15th 35 12/12 Flowing,
border'*' 246/271 249/288 51-05 10 50 8.4 / 7.0 260/259 GL-05 10 50 9.2 / 9.8 2 278/322 51-05 15th 50 9.8 / 10 2 243/214 GL-05 15th 50 5.1 / 4.6 1 213/218 51-05 10 65 2 2, GL-05 15th 65 2 2, 51-05 1 1, 2, 1, ο,

1) Slidability of machined metal against foil;

2) Foil brought into equilibrium with a rel. Humidity of 58%; Film thickness 0.0503mm (2 mils);

3) Foil brought into equilibrium with a rel. Humidity of 58? Ί; Foil thickness 0.0381 bin 0.0432 am (1.5 to 1.7 mils); the pillow pack measures 21.6 cm 16.5 cm and contains 454 g

Lannate ^R 90WD;

4) pressure roller lined with Teflon -impregnated glass fabric tape;

5) kg / mm ² ;

6) I. Machine direction / transverse direction.

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BA-8O69-A

example k

Simulated handling of the filled packs

Two pillow packs with a thickness of 0.381 to 0.457 mm (1.5 to 1.8 mils) and a width of M3.2 cm or 16.5 cm are made by kiss-sealing extruded films based on 100 parts of Elvanol ^R 51- 05 or Gohsenol ^R GL-05 with 15 parts or 10 parts of Carbowax 4OO. The packs are each filled with 2.28 kg (5 lbs) of semolina sugar, sealed and placed over power at 25 % rel. Balanced moisture. The packs are then allowed to fall one after the other from heights of first 91> 4 cm and then 183 cm onto a tiled floor without leaks or noticeable damage occurring. ·

R R

One of 100 parts Elvanol 51-05 / 15 parts of Carbowax ¹ IOO forth asked, 38.8 cm 38.1 cm χ measured heat-sealed pillow pack having a thickness of 0.0381 mm (1.5 mils) which 4.54 kg semolina Sucker contains, is placed in a 11.3 liter Fiber Size and from 91, ¹ I cm height dropped onto the ground; no break occurs. The entire intact foil pack can easily be transferred into a spray tank by splitting the cardboard upright.

Pillow packs are produced which contain 227 6 or 908 g of Lannate 9OV / D, with the help of an automatic vertical generation and filling packaging machine using a blown film based on 51-05, and.GL-05. with a content of

r>

15 parts by weight of Carbowax 400 each. The machine works with intermittent drive and creates vertical seals using a constantly heated bar as well horizontal impulse seals with a nichrome tape. The production speeds are 15 to 30 packs / minute.

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Dimensions of the pillow pack, cm

^P eweight ^S "p ^{Film thickness} » ^mm (mils) Height Width + 227 0.0305 - 0.0381 (1.2 - 1.5) IH - 15.2 '16.3 908 0.0381 - 0.0508 (1 , 5-2.0) 30.5 17.3

+) when laid flat

The pillow packs weighing 908 g or 227 g are 50 % rel. Moisture-equilibrated, provided with an outer sheath cooled 0 ⁰ C (as in Test IV C) and 1O ⁰ C respectively. Both packs can withstand falls from a height of 122 cm. The same results are achieved if the wrapped packs are packed in cardboard boxes (5.5 kg per box), cooled and the boxes are dropped from a height of 122 cm once on the floor and once on each of the two sides.

Example 5 Storage of the filled pack and spraying

Double pillow packs are made (height 6.35 cm 7.62 cm Width) from about 0.038l mm (about 1.5 mils) thick melt-extruded film based on 100 parts of Elvanol 5I-O5 / 15 parts of Carbowax 400 and fills them with

- R 10 g one of several pesticides / Lannate 90WD Methomyl (insecticide), Lorox ^R 5OWP Linuron (weed killer), Manzate ^R D

R R

Maneb (fungicide), Benlate Benomyl (fungicide), Hyvar X

Bromacil (weed killer), Tupersam 50 Siduron (weed killer), R R

Marlate 50 Methoxychlor (insecticide) and Thylate Thiram (fungicide)? and puts them in moisture-proof covers made of a polyethylene / aluminum foil / kraft paper laminate. After the outer casing has been heat-sealed, the package is placed in an oven and kept at 45 ^° C. for 21 days; In this way, storage of the pesticide for about one year is simulated. The chemical analysis shows that the active ingredient content does not change during storage. All packs can be easily removed from their sleeves and pass the spray test. The same

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Results will be achieved with pillow packs with Lannate * in 16 months of age Raurataperaturlager achieved.

RR R

Three of the spray tank solutions (Lannate, Benlate and Manzate) are tested for biological activity; it is found that their activity is that of comparison solutions of the same Pesticides.

Example 6 Blown film extrusion on an industrial scale

According to Example 1, tape mixes are prepared from the following recipes:

a) 100 parts of Gohsenol GL-05 (with a content of 0 or

15 parts Carbowax 400

5 parts water)

b) 100 parts of Gohsenol ^R GL-05 (with a content of 0 or

20 parts Carbowax ^R 400

5 parts water)

c) 100 parts of Gohsenol ^R GL-05 (with a content of 0 resp.

5 parts water)

R.
15 parts Carbowax 400

2 parts of polyethylene oxide (Polyox ^R WRPA 3154, Union Carbide,

Weight average molecular weight 900,000)

The batches are each fed into the twin-screw extruder (Example 3), which is equipped with a mold with two holes with a diameter of about 0.64 cm. There is produced a clear, ausschwitzungsfreier strand and quenched with air knives, the preferred cylinder mold temperatures 190 to 210 ⁰ C amount (at melt temperatures of about 200 ° C escape disgusted very low pressures, a part of the composition a) is at 130 extruded up to 180 ° C). The strands are cut into pellets, which are allowed to cool under nitrogen and fed into a 6.35 cm Eagon melt extruder (Frank W. Eagon & Co .;

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Bound Brook, NJ) feeds a single screw of a type commonly used in the extrusion of Alathon ™ polyethylene Tubing is cooled with an air ring, air inflated, compressed, pinched and transferred to the winding zone. The compressed tubing is 0.0127-0.127mm (0.5-5 mils) thick and up to 91 flat widths .4 cm is produced at speeds of up to 54.5 kg / hour (about 13.7 m / min.) The cutting, delaminating and winding, which take place in one operation, is achieved within a range of about 30 to 65 % rel. Table III shows the working conditions used for the three compositions.

Table III

Dr * u eic joint temperature of the melting k / mm ²

Settlement of cylindrical disk, C temperature, C ^δ

(a) 185 - 205 (b) 165 - 185 (c) 193 - 200

200-210 2.4 I85 1.4

200 2.1

The films obtained are almost colorless, exuding and void-free and contain a small amount of gel. Films (a) and (b) are clear, while film (c) has a slight haze having. The film (c) has a lower tack and a better sliding property with a high rel. humidity and excellent bending properties at low temperature (-15 C). The properties of the films are shown in Table IV.

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Table IV

Blown film

Foil
TO-
together-
settlement - (b) rel.
Damp
tig
ability, ^ Module ¹ ) train
firm
speed ¹ ' Flow
border ' Deh
nung, i » number of
Scanning
-Bending-
cycles Elmendorf-
-Crack-
fixed ^ g- Polian
disc Spray
tank- Pack
fell (a) (c) 20th
35 158/134 12 / 8.4 212/232 216/125
332/346 38/1 1 90 -KaIt-
water-
soluble-
³ * -KaIt-
water-
soluble-
ability3) 50 11/13 3.3 / 2.1 145/180 0.3 Eruch
1.0 separation λ testing, at
O ³ C 62
31 0.1 sink ⁴ ^
0.8min / niil confessed 20th
35
50 137/177 12 / 6.3
2.8 / 2.1 2.8 / 2.1 198/166
212/220 116/94
331/301 42/468 0.1 sink no

1) kg / mm

2) g / 0.0254 mm (mil); ASTM method D 1922-61T, 1964 Standards, Part 27, page 642

3 minutes

4) 0.0356 mm (1.4 mils)

5) O »O33O mm (1.3 mils)

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From Table IV it can be seen that the stretching in de: real extrusion and in winding leads to an orientation,
by which the tear strength is greatly increased; in the
In recipe a), for example, there is a 30-fold increase in tensile strength TD * versus MD *. This advantageous effect cannot be achieved by simple solvent pouring. The orientation achieves further advantages related to the toughness. A filled pack made of a film cast from aqueous solution (100 parts by weight 51-05 and 15Gev, non-part Carbowax ^R 400) fails in the pack drop test ( ⁰ ° C., 50% relative humidity). *) TD = transverse direction; MD machine direction.

All of these slides pass all standard tests and show
a foil disk cold water solubility of 0.5 to 0.8 inch / 0.0254 mm (0.5 to 0.8 min / mil). Breaks during the spray tank test

a pillow pack made from film (a), polygamy 227 g Lannate contains, after 0.3 minutes, while the contents are released after one minute and dissolve in less than 3 minutes completely solves. Similar results are obtained if the blown film extrusion using Elvanol 51-05

R R

instead of Gohsenol GL-05 with 15 parts by weight of Carbowax 400 repeated.

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Claims (15)

Claims 1. Composition for the production of melt-extrudable cold water-soluble films, consisting essentially of 5 to 20 parts by weight of a polyethylene glycol with an average molecular weight (weight average) of about 325 to 550 in 100 parts by weight of a polyvinyl alcohol with a low molecular weight, which is saponified to 85 to 90% and a has a viscosity of 3 to 10 cps measured on a 4 percent aqueous solution at 20 ° C. 2. Composition according to claim 1, characterized in that the polyethylene glycol has an average molecular weight from 380 to 420. 3. Composition according to claim 1, characterized in that the polyvinyl alcohol is 87 to 90 % saponified and has a viscosity of 4 to 6 cps measured on a 4 percent aqueous solution at 20 ° C. 4. Composition according to claim 3 »characterized in that the polyethylene glycol has an average molecular weight from 380 to 420 and in a proportion of 12 to Parts by weight per 100 parts of polyvinyl alcohol is present. 5. Composition according to claim 3, characterized in that the polyethylene glycol has an average molecular weight from 380 to 420 and in a proportion of about 15 Parts by weight per 100 parts of polyvinyl alcohol is present. 6. The composition of claim 1 containing 2 or less parts by weight per 100 parts of polyvinyl alcohol of a water-soluble polymer having an average molecular weight of at least 600, which poly- - 29 - 098 29/0948 ΒΑ-8Ο69-Λ represents ethylene oxide or polyethylene glycol. 7. Composition according to claim 6 with a content of 2 or less parts by weight per 100 parts of polyvinyl alcohol of a water-soluble polymer, which polymer is a polyethylene oxide with an average molecular weight of 500,000 to 1,000,000 or a polyethylene glycol with a Represents average molecular weight of at least 600. 8. Composition according to claim 1 with a content of 5 or less parts by weight of an adjuvant per 100 parts by weight Polyvinyl alcohol. 9. The composition of claim k with a content of 0.5 to 1 part by weight of an adjuvant per 100 parts by weight of polyvinyl alcohol. 10. A composition in the form of a melt-extruded cold water soluble film having a thickness of 0.0127 to 0.25 mm I ^1, consisting essentially gemä'ss from the composition of claims 1 to 9. 11. A method for producing a composition in the form of a cold-water-soluble film, characterized in that that a composition according to claims 1-9 is melt-extruded. 12. Composition according to claim 1 with a content of 2 parts by weight or less per 100 parts of polyvinyl alcohol of a water-soluble polymer having an average molecular weight of at least ^ l00, where that - 30 509829/0948 BA-8O69-A Represents polymeric polypropylene glycol or an ethylene oxide / propylene oxide copolymer; 13. Composition in the form of a melt-extruded cold-water-soluble film with a thickness of 0.025 * 1 to 0.127 mm, essentially consisting of the composition according to claim 12. 1 * 4. Process for the preparation of a composition in the form a cold water-soluble film with a thickness of 0.025 * 1 to 0.127 mm, characterized in that one Composition according to claim 12 melt-extruded. 15. Composition in the form of a film according to claim 10, characterized in that it has a water content of 5 to 7 % . - 31 - 5 0 ^ 9829 /, 0948