CH672474A5 - - Google Patents

Description

DESCRIPTION

The present invention relates to a method for producing a shock-absorbing packaging material body made of plastic film, with a plurality of bulbous units in which gas is contained.

The prior art shows various forms of shock absorbing packaging material bodies, including non-hollow bodies, which are spherical or spaghetti-shaped and made of foamed plastic. Such shock absorbing packaging materials do not produce complete shock absorbing effects and often behave hydrodynamically, so that the packaged item is exposed to undesirable movements and vibrations while the packaging material deforms itself. In addition, such known shock absorbing packaging material bodies often have unsatisfactory shock absorbing properties, are difficult to handle and are expensive due to the fact that additional amounts of plastic are necessary because the packaging material bodies are not hollow. Furthermore, the known packaging material bodies, in which an attempt has been made to use a hollow instead of a foamed body, have shapes which do not simply allow complete and effective filling of empty spaces around the object to be packaged and also do not occur within a large range during the shipping temperatures maintain completely sufficient shock absorbing properties. As a result, more work units are required, with the result that there is a reduced shock-absorbing compression property and deformation property.

The aim of the invention is to remedy the disadvantages mentioned above.

The method according to the invention is characterized by the features of independent claim 1.

According to the present invention, a shock-absorbing packaging material is therefore proposed, which is made from a plastic material and advantageously contains a sequence of largely triangular or tetrahedral gas-filled units, which are heat-welded and can be used to fill the areas around the object to be packaged and also sufficient shock-absorbing properties in a wide range of Tempe2

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maintenance conditions. In an apparatus for carrying out the method, seam welding rollers for welding the overlapping side edges of the film to form a tubular body are present, deformable rollers which are arranged downstream of the seam floating rollers and serve to abut the side sections and the tubular body to advance in the direction of transport, a line, by means of which cold gas is introduced into the tubular body, and lateral or horizontal and vertical welding members, which are arranged in series and are arranged in the direction of transport after the sponge rubber-shaped rollers and serve to give the tubular body a preferred shape to be welded so that effective packaging and shock absorption is possible.

The shock absorbing packaging material produced according to the method can be suitable for mass production with low costs and simplified manufacturing devices.

Furthermore, the shock-absorbing packaging material can make good use of space and can fill gaps around the packaged item, so that unprotected areas around a respective packaged item can be avoided.

The shock absorbing packaging material formed according to the method may be able to maintain its highly desirable shock absorbing properties over a wide range of temperatures. With the method, shock-absorbing packaging bodies can be produced economically with increased production speeds, which can show an improved shock-absorbing property and an improved packaging.

The subject matter of the invention is explained in more detail below with reference to the drawings, for example. It shows:

FIGS. 1 and 2 show a schematic representation of an embodiment of a production method for producing the shock-absorbing packaging material body from plastic film and according to the present invention,

FIG. 3 shows a diagrammatic view of an embodiment of a shock-absorbing packaging material body designed according to the invention,

FIG. 4 shows a diagrammatic representation of an embodiment of a shock-absorbing packaging material body which has a cut or tear line in each of the welded sections,

FIG. 5 is a perspective view, showing how shock-absorbing packaging material bodies designed according to the invention can be used effectively for packaging an object,

FIG. 6 shows a simplified diagrammatic view of a device for processing and using a flat film for the production of shock-absorbing packaging material bodies according to the invention,

FIG. 7 shows a side view of the device for producing shock-absorbing packaging material bodies shown in FIG. 6, further details being shown,

FIG. 8 shows a top view of the device according to FIG. 7, FIG. 9 shows an end view of the device shown in FIG. 7,

FIG. 10 shows an embodiment of a shock-absorbing packaging material body which has been produced by the device shown in FIGS. 6 to 9,

FIG. 11 shows the cycle sequence of the work of the horizontal and vertical welding members of the illustrated device for illustrating the introduction of a gas and the trapping of the gas in a bulbous, hollow packaging material body unit of the present invention,

Figure 12 is a graph showing the amount of deformation of the shock absorbing packaging material body of the present invention containing gas filled units, the behavior of which is shown, on the one hand when gas is introduced at ambient temperature and on the other hand if gas with the more desirable temperature 22 ° C below ambient io temperature has been introduced, and

FIG. 13 shows a diagram in which the deformation work for shock-absorbing packaging material bodies is shown, again showing the behavior with gas introduced at ambient temperature and with gas that 22 ° C. has been introduced below -15 ambient temperature.

Although any number of plastic films can be used to practice the present invention, a laminated film is preferred which is constructed from two different plastics with different melting points 20. The plastic films are selected with regard to strength, elasticity and melting point. A laminated film composed of polyethylene and polyester or polyamide (nylon) is most advantageously used. The thickness of the film is not limited, but in the practical embodiment for polyethylene in a range from about 10 to about 50 microns for polyester about 10 to about 20 microns and for polyamide about 10 to about 20 microns. However, it has been found that preferably foils with a thickness in the range of 9-30 microns are sufficient to have sufficient strength at the lowest cost. If a polyethylene-polyethylene terephthalate film is used, a total thickness in the range of 12-30 microns is used. If a three-layer film of low density polyethylene, 35 high density polyethylene and polyethylene terephthalate is used, the film density is 10-10-12 microns, so there is a total thickness of 32 microns.

For example, it has been found that a coextruded plastic film made by Dai Nippon Printing Com-40 pany is made from a linear low density polyethylene with a melting point between about 160 ° C to 180 ° C and a polyethylene terephthalate with a melting point between about 230 ° C and 240 ° C, which are bonded together with a low density polyethylene adhesive, forms the best film that is desirable for practicing the present invention. The low melting point polyethylene helps create tight welds in the product, while the polyethylene terephthalate helps maintain the shape of the web. The use of composite foils, which are separated from foils with different melting points, contributes to the perfect, tightly welded and easily deformed properties of the resulting shock-absorbing packaging material bodies.

The diameter of the cylindrical body used to produce the shape of the present packaging material is not limited and in practice is chosen from a number in the range from several centimeters to 60 multiples of 10 cm, a range of 4-10 cm is preferred . Furthermore, the welding is carried out at intervals of several centimeters up to a multiple of 10 cm, advantageously at intervals of 4-10 cm.

Although various inert (chemically inert) gases can be partially used to practice the present invention, air is preferred because air is readily available and cheaply available. Alternatively, nitrogen can be used because it is in a liquid state

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is available because it is cheap and in a liquid state in a cooled state so that this gas can be introduced without additional cooling. A gas that is controlled to be cooler than the ambient air temperature, preferably about 10 ° C to 20 ° C or even cooler than ambient air, gives the desired shock absorbing properties. This means that if the temperature of the gas which is sealed in the cylindrical body is the same as the temperature of the ambient air, this gas will expand during the welding process due to the existing temperature. As a result, if the temperature in the hollow units formed by the vertical and horizontal welding takes on a value equal to the ambient air, the hollow units can collapse a little, so they can no longer be bulky. Conversely, if a gas is contained in the units that has been controlled to be colder than the ambient temperature, the temperature within the hollow units will increase after a period of time until it reaches the same value as the ambient temperature, so that the gas expands. As a result, the units swell up so that they become plump and the shock-absorbing effect is enhanced.

In particular, it has been found that the temperature difference between the ambient temperature at which the manufacturing process takes place in practice and the temperature at which the gas is introduced into the hollow gas-filled units can influence the properties of the shock-absorbing plastic packaging material body finally produced. It is desirable that the temperature difference be such that a fully inflated, rigid unit structure is formed which exhibits high shock absorbing properties over a wide range of packaging conditions. At a temperature difference of 10 ° C, the gas-filled units typically have a rounded shape with sufficient shock-absorbing properties. With a temperature difference of 15 ° C the swelling is stronger and the shock absorbing properties are also stronger. And at a temperature difference of 20 ° C, the shape of the gas-filled unit is rigid and the desired shock-absorbing properties are achieved. A temperature difference of more than 20 ° C gives extremely satisfactory results, but is not desirable in practice because the need to cool the introduced gas further increases the manufacturing costs.

Because it is obviously difficult to create an overpressure state in the individual gas-filled units by introducing gas with temperatures higher than ambient temperature, introducing a cooled gas (for example air) is a temperature that is equal to the ambient temperature or a temperature that is only a small one is slightly higher than ambient temperature, and which gas can then increase its temperature in order to pressurize the individual gas-filled units has been chosen as a particularly advantageous solution. In practice, the gas contained in the units has been introduced at a pressure slightly higher than ambient pressure, between about 98 Pa to 980 Pa and preferably between about 196 and 343 Pa. At pressures higher than 980 Pa, it becomes more difficult to seal the individual units, while at pressures below 98 Pa there is the difficulty that the individual units do not expand properly to their inflated state.

An additional advantage of using a cooler gas is that it increases the productivity of the packaging material manufacturing process because the cooled gas causes the welds to cool faster, i.e. the partially melted seam sections, which form the boundaries of the individual gas-filled units, and thus the adhesion of the seam, the solidification is accelerated. It is therefore found that when operating under ambient conditions of 32 ° C (as the basic state) with a temperature difference of 12 ° C, productivity increases of 9%, with a temperature difference of 17 ° C of 15%, with a temperature difference of 22 ° C 23% and at a temperature difference of 32 ° C 54% has been achieved.

Although the welding can be carried out at different angular states, the welding is preferably carried out essentially vertically and horizontally. The welding should advantageously be carried out alternately in the vertical and horizontal directions. The hollow units thus obtained are triangular or tetrahedral in shape and inflated in cross-section and rounded if they contain a gas which is cooler than ambient air. The use of space in the triangular shape is better and leads to an increase in the desired packaging properties, which include, among other things, reducing and dampening the movement of the objects surrounding it.

The welding of the individual units is advantageously carried out at temperatures and pressures which permit an acceptable tight welding, so that the gas introduced does not escape. If a laminated film is used, the welding temperature is at least higher than the melting point of the plastic that has the lowest melting point, but lower than the melting point of the respective plastic with a higher melting point. As a result, there is only partial melting of the plastic film composed of two or three components, i.e. only one of the components melts. For example, in the case of a film composed of polyethylene and polyethylene terephthalate, a range from about 130 ° C to 180 ° C is an acceptable welding temperature range, with the range from about 160 ° C to 180 ° C being preferred. At temperatures above 180 ° C, the polyethylene terephthalate component would be damaged, while at temperatures above 230 ° C, the polyethylene component would be damaged. In practice, the welding pressures are kept as low as possible in order to achieve perfect welding. If the dwell time is extended, the pressures can be kept substantially lower, for example below about 390 x 103 Pa. At pressures higher than 980 x 103 Pa, the edge sections of the seals or welding points could be damaged.

The generally triangular shape, or shape, shown in Figures 3, 4 and 10 produces a product which is very effective in terms of packaging and absorbing shocks. The interconnected units, which are for example in series form, form a high degree of shock-absorbing property and also contribute to the corner areas of the packaging container being filled well. In addition, the largely triangular shape mentioned contributes to the fact that the packaged object is completely surrounded and that empty spaces in the packaging container are reduced, which shape also simply fits into the corner areas, as shown, for example, in FIG. 5. If the hollow, gas-filled, bulged units are arranged side by side, empty spaces and corner areas can be filled more easily. In addition, the training has the effect that the individual units are connected to one another in series, such that

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the body thus formed is less mobile, which increases the efficiency of work and improves the overall shock-absorbing properties.

Therefore, the desired shape of the gas-filled bulbous units of the present invention is one that effectively fills the gaps and corners in the packaging container and completely and effectively surrounds the packaged item while having an excellent shock absorbing property.

Although the triangular or tetrahedral units shown in FIGS. 3, 4 and 10 are preferred, because they bring about an improved use of space and shock absorption and at the same time prevent the objects surrounding them from moving, it should be noted that other shapes, which have the effective filling and shock absorption properties according to the triangular shape can also be used for carrying out the present invention. For example, if a cylindrical body with a smaller diameter is used, pillow-shaped units can also be effective. In such cases, horizontal and horizontal pressurized welding may be used to form the pillow-shaped units, or alternatively vertically and vertically, although the vertical-vertical arrangements tend to form irregular welds from time to time. Alternatively, the welds can vary in terms of the angular position from horizontal or vertical.

If tear lines or cuts are made in the welded sections of the hollow units, as shown in FIG. 4, a desired length can be cut off without the need to use knives or scissors and thus the efficiency in handling the packaging material is increased . The cuts may be, for example, a sewing stitch-like cut, a cut having a series of slits, a tear line, and the like, except at both ends. The perforations, cuts or tear lines can be arranged in any welded section of the packaging material body formed, often advantageously in each welded section and in other versions, in every second or every fourth welded section.

An example of a method useful for making shock absorbing packaging material bodies made in accordance with the present invention.

will now be described with reference to Figures 1 and 2.

As is generally shown in FIG. 1, a laminated film is initially formed in a conventional, known manner and the edges of the laminated film are welded to one another, so that a continuous, uninterrupted cylindrical body 1 is produced. According to FIG. 2, the cylindrical body 1 obtained in this way is then welded in appropriate sections at l (a) and l (b), for example as shown in essentially a vertical (V) and horizontal (H) direction, so that a shock absorbing packaging material body is produced according to the present invention, which contains a plurality of roughly triangular, hollow units which are connected to one another in series. FIG. 3 shows a perspective view of an embodiment of such a shock-absorbing packaging material body, which is designed according to the present invention. The welding under pressure is carried out at a temperature of approximately 130 ° C. to 180 ° C. and at a pressure between approximately 390 × 103 Pa and 980 × 103 Pa and for 0.3 to 0.7 seconds.

It is obviously desirable that the bulbous, gas-filled units maintain their solid shape and effective shock-absorbing properties within a wide temperature range to which the packaged article is exposed. After air, nitrogen, or any other suitable gas has been introduced and sealed thereon in the individual units of the shock absorbing packaging material body, the pressure within the gas-filled units tends to rise on return to ambient temperature because the volume thereof remains relatively unchanged , because plastic film is relatively inelastic. Thus, if the temperature of the gas rises, the pressure will rise. Each hollow gas-filled unit, in the preferred bulbous shape, will retain its original, expanded shape until the ambient temperature is reduced to such an extent that the pressure within each unit has dropped to a level below ambient pressure, for example 98.07 x 103 Pa. After that, the units will lose about 10% of their volume for every 30 ° C decrease in temperature. With regard to the upper limit of temperature, it has been found that temperatures higher than 70 ° C are undesirable and form a practical limit on the temperature to which the packaging material as a plastic should be exposed during service. Obviously, the units will maintain their expanded, fully pressurized condition at temperatures above ambient during actual manufacture, and as explained above, the volume will decrease to an extent that is approximately 10% per 30 ° C decrease in temperature below ambient remove during the manufacturing process. If the volume of the units falls below 80% of the maximum expanded volume, the resulting packaging material will quickly lose the desired shock-absorbing properties. This state is reached, for example, when the temperature to which the gas-filled units are exposed falls approximately 60% or more below the temperature at which the cooled air was introduced.

Various aspects of embodiments of the present invention are described in detail by means of the following examples only for the purpose of illustration, the invention itself being in no way restricted to these examples.

example 1

A laminated film, which is a layer of polyethylene "SUMIKASEN (exact spelling in Latin letters unknown)" and manufactured by SUMMITOMO CHEMICAL CO., LTD., And which had a thickness of 20 microns and a polyester layer "LUMILAR (exact spelling in Latin letters unknown) »by TORAY INDUSTRIES, INC. (also known as TO-YORO) and 12 microns thick was made using a conventional method. Then, as shown in Figure 1, the opposite edges of the laminated film were welded together under pressure so that the inner polyethylene layer reached a temperature of 150 ° C and a pressure of 490 x 103 Pa was used, so that a continuous cylindrical body 1 with a diameter of about 6 cm was formed. Thereafter, this cylindrical body was welded again with the application of pressure vertically (V) and horizontally (H) in an alternative sequence at a respective distance of 7 cm, during which time air

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was blown into the cylindrical body. This method now forms a packaging material body which has a plurality of roughly triangular units 2 which are connected to one another in series, the edge length of each (tetrahedral) unit being approximately 9 cm, as is generally illustrated in FIGS. 2 and 3.

Example 2

A laminated film was produced which was made of a polyethylene film "SUMIKASEN" with a thickness of 20 microns and a polyamide film "AMILAN (exact spelling in Latin letters unknown)", which was manufactured by TORAY INDUSTRIES, INC. is produced and had a thickness of 15 microns. A shock absorbing packaging material body was then made from this laminated film, following the same procedure as described in Example 1, except that the air temperature was varied. The results obtained are shown in Table I. The manufacturing process mentioned above was carried out at about 10 ° C and ambient pressure.

Table I

Air temperature (° C)

10th

Condition of the hollow, gas-filled unit when the internal temperature reached a value equal to the ambient temperature (10 ° C)

Elasticity is poor and the absorption of shocks is insufficient.

The roughly tetrahedral shape is retained, but the absorption of impacts is unsatisfactory.

Almost approximates the expected rounded shape, but sufficient absorption of impacts has not yet been obtained.

-10

zesses lay. As a further example, the following data show the state of the individual gas-filled units at different temperatures of the gas:

Table II

Temperature difference between ambient air and introduced air (° C)

0

15

20th

10th

25th

15

20th

30th

State of the hollow unit

Poor elasticity and insufficient absorption of shocks.

Maintain a tetrahedral shape, but insufficient absorption of impacts.

Almost completely achieves the expected rounded shape, but sufficient shock absorption has not yet been obtained.

Swells to be pretty hard and absorbing shocks pretty satisfactorily.

Swells to be hard and has good shock absorption.

35

40

Swells to be pretty hard and absorbing shocks is largely satisfactory. 45

Swells to be very hard, with good shock absorption.

50

Example 3

In the sections (V) and (H) of the shock absorber which were welded under pressure and were produced in accordance with Example 2, slit-shaped cuts or tear lines 3 were formed, air being present in the respective units and cooling to a value of 10 ° C. below the ambient temperature has been. FIG. 4 shows such a packaging material body with several units, in which cooled air is arranged.

Example 4

As mentioned above, the shock absorbing packaging material bodies produced according to the present invention show the best shock absorbing properties when they have been filled with gas which is at least 10 ° C. and advantageously 20 ° C. below ambient temperature during the manufacturing process.

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FIG. 5 shows the use of the shock-absorbing packaging material bodies 2 which are designed in accordance with the present invention. The reference number 4 designates the article to be packaged and 5 designates a container in which the article 4 is packed or shipped. The shock absorbing packaging material bodies of the present invention have been found to have improved static and dynamic shock absorbing properties. For example, drop tests were conducted in which a 100 N apparatus packaged in a polycarbonate container and packing material body of the present invention was dropped every 90 hours from a height of 60 cm for 8 hours. No deformation or damage to the packaging material bodies was observed and the shock-absorbing properties of the same remained unchanged.

FIGS. 12 and 13 show how the shock-absorbing properties change when the temperature of the gas introduced into the units is changed during filling. For example, at the time of manufacture, when the packaging material bodies of the present invention are filled with a gas at a temperature of 22 ° C below ambient temperature and the comparison is made with a temperature difference of 0 ° C, the difference in the degree of compression of the finally shaped packaging material body is when subjected to a load of 75 N, at a temperature difference of 22 ° C 15 cm and at a temperature difference from 0 ° C to 12 cm. This means that the packaging material bodies ultimately produced are then unable to withstand forces (they are compressed too much) when the temperature difference when the gas is filled approaches 0 ° C. In the same way, under the same loading conditions, the deformation of packing material bodies which occurs under the action of force and which is

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that the temperature is 22 ° C colder than ambient temperature (curve A), smaller than that of packaging material that has been filled at a temperature difference of 0 ° C (curve B). Under ideal deformation conditions, the packaging material bodies, which were filled with gas at a temperature difference of 22 ° C, will absorb more pressure energy and thus have better shock-absorbing properties (Fig. 13).

Thus, the shock absorbing packaging material bodies produced have the advantages that they are an economical packaging material and filling material and are able to achieve a large space utilization at low costs. Because the device for producing the packaging material bodies are relatively simple, they can be manufactured at the respective work station itself. Further, the shock absorbing packaging material alleviates static electricity problems encountered with other packaging materials, i.e. this packaging material does not fly against the ceiling or adheres to the person who opens the packaging container. It can also be used repeatedly 5. Furthermore, it can be removed very simply by simply inserting the hollow units so that the gas trapped therein can escape. Moreover, the shock absorbing packaging material of the present invention exhibits all of the highly desirable packaging, filling and shock absorbing properties that have been described in detail above.

As is shown in even greater detail in Table III below, the temperature difference between ambient air and the captured or introduced air (at the time of introduction) influences both the volume of the hollow gas-filled unit and the pressure within the respective unit .

Table III

Temperature difference from the environment (° C)

-10

Volume of

temperature

Theoreti

volume

Pressure broke

Ambient air in the air (° C)

volume with hollow cavities

(ml)

each one

unit

A

league tempe

(ml)

Ness

rature (ml)

Pa x 103

8th

157.1

148

104.05

10th

158.2

149

104.15

15

161

150

105.23

147

20th

163.8

151.5

106.01

25th

166.6

152

107.48

30th

169.4

153

108.56

35

172.2

153.5

110.03

- 5th

147

10 15 20 25 30 35

154.1

155.2 158 160.7 163.5 166.2 168.9

148

149

150 151.5

152

153

154

102.09 102.19 103.27 104.05 105.52 106.50 107.88

147

10 15 20 25 30 35

151.3

152.4

155.1 157.8

160.5

163.2 165.8

148

149

150 151.5

152

153

154

100.23 100.33 101.40 102.19 103.56 104.64 105.92

4- 5

147

10 15 20 25 30 35

148.6 149.6 152.3 154.9 157.6 160.2 162.9

148

149

150 151.5

152

153 153.5

98.46 98.46 99.54 100.23 101.89 102.68 104.05

The device which processes the films in order to produce the shock-absorbing packaging material bodies according to the method according to the invention will now be described below. FIGS. 6, 7, 8 and 9 show an embodiment of a device which carries out a sequence of successive steps which are carried out to form the shock-absorbing packaging material bodies. The device shown has stations at which a film 6 via a guide roller 7 and

60 is moved between a pair of transport rollers 8, 9 against a second guide roller 10. The film 6 is then guided forward or in the transport direction to the next station, a shaping unit 11, which forms the film into a tubular member.

65 This shaping unit 11 has a vertically standing plate 12 which serves to guide the film upwards and has a table plate at its upper end. The shaping unit 11 also has triangular folding plate

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th 13,13, which run downwards from the upper end of the vertical plate 12 and serve to fold the side edges of the film upwards. There is also a lower plate 14 which serves to exert pressure on the upper side of the film 6, which runs between the folding plates 13, 13 in the transport direction.

FIG. 7 shows that a cutting member 15 and a magnetically operated magnetic switch 16 are arranged behind the vertically standing plate 12. The cutting member 15 is actuated by the magnetic switch 16 so that the film 6 is slit while it is being advanced by a predetermined distance. The Schneidegüed 15 is clamped away from the film 6 by means of a spring 17 and is only moved forward when an electric current flows through the magnetic switch. The magnetic switch 16 is controlled by a memory counter, not shown.

A pulling roller device that contains pulling rollers 18, 18, a heating device that contains preheating rods 19, 19 and a seam welding roller device with seam welding rollers 20, 20 are arranged one behind the other and one after the other in the transport direction in front of and above the shaping unit 11. The pull rollers 18, 18 pull the film in the transport direction by resting on the side edges of the film, the preheating rods 19, 19 basically weld the film along their entire length, while the seam welding rollers 20, 20 weld the film completely along their entire length.

A transport device for the tubular body has sponge rubber rollers 21, 21, by means of which the film 6 is transported further. The sponge rubber rollers 21, 21 are arranged in front of the seam welding rollers 20, 20, which in turn are connected to vertically standing shafts 22. The sponge rubber rollers 21, 21 rest on the side edges of the film 6 and push the film further with a largely uniform movement. A conductor 23, which is connected to a compressor (not shown), is connected to an injection pipe 24 via a low-temperature apparatus 25, by means of which the air or the gas is cooled. This low-temperature apparatus 25 serves to cool the air to a temperature approximately 20 ° C. below the ambient temperature when the air or the gas is blown into the film. The blow-in pipe 24 extends above the upper plate 14 in the direction of travel of the film and runs between the sponge rubber rollers 21, 21 and ends in front of these sponge rubber rollers. A pressure sensor 26 and a temperature sensor 27 are arranged next to the outlet of the injection pipe 24 and serve to control the inflow of the cooled air.

A horizontal welding device has horizontal welding members 28, 28, which build up a notching or indentation device, which horizontal welding device is arranged in front of the sponge rubber rollers 21, 21. Each welding member is arranged on a horizontal, rotating shaft 29. A vertical welding device has vertical welding members 30, 30 and is arranged in front of or upstream of the horizontal welding device. The vertical welding members 30, 30 are connected to rotatable shafts 31 such that they relatively cross the horizontal welding members 28, 28. A transport member 32 and a groove 33 are arranged in front of the welding members 30, 30.

In operation, the film 6 is unwound by the transport rollers 8, 9 and shaped into a tube by the shaping unit 11. The overlapping edge regions of this tube are heated by the preheating rods 19, 19, so that they are underneath by the seam welding rollers 20, 20

Pressure is welded tightly together. The blowing tube 24 thus now projects into the film 6, which is now in a tubular shape. While the sponge rubber rollers 21, 21 primarily serve to prevent the supplied air from leaking out of the tubular film 6, they also lie against the sides of the film and transport it in the conveying direction. The rollers 21, 21 rotate at a speed such that their peripheral speed is higher than the linear transport speed of the film 6, so that the film is transported in such a way that it does not sag.

The blow-in tube 24, which is surrounded by the tubular film 6, blows in compressed air, which causes the film to bulge, which compressed air in the section of the tubular film which is behind the sponge rubber rollers 21, 21 is sufficiently cooler than the ambient air is. The leading end of the now sufficiently bulged tubular film 6 is completely sealed by the vertical welding members 30, 30 and then the film is tightly welded by the horizontal welding members 28, 28.

The horizontal welding members 28, 28 simultaneously form a notch in the welded section la, which is represented by the tear line 1b, as can be seen from FIG. By alternately arranging vertical weldings (V) and horizontal welds (H) in the film in this way, a sequence of triangular or tetrahedral hollow body units A can be produced and these bodies are formed by the transport member 32 and the channel 33 issued by the device.

As soon as a defined amount of the film 6 has been fed in each case, electric current is supplied to the magnetic switch 16, so that the cutting member 15 is actuated and thus a defined film section A is scored and / or slit. As a result, the counting of the hollow bulbous units (section A) formed by the finished hollow body units which are welded and grooved at slotted intervals is simplified.

It can be seen from FIG. 11 that the operation of this invention is supported by the arrangement of a fixed clock sequence which allows the individual elements described to be operated in a controlled manner. According to the figure, the time period t3 is the time period during which a complete section A is formed and welded at both ends. The time span t2 relates to the welding of a section A of the tubular film 6 by the vertical welding members 30, 30. The time tj relates to the welding of the same section A by the horizontal welding members 28, 28, which welding advantageously takes place a short time after the welding by the vertical welding members 30, 30. This cycle sequence allows gas to be trapped in each section A after it has been shaped and sealed. While a clock sequence has now been described, according to which first filling of the tubular film and welding of each section A thereon has been described, it is evident that the method and apparatus of this invention provide different operating clock sequences (ie t2 and t3) are.

According to the present invention, a series of shock-absorbing units in the form of tightly welded hollow triangular or tetrahedral bodies can be produced automatically. In addition, cooled and pressurized gas is trapped in each of these hollow bodies. This creates the desired ver5

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Improved quality of the shock absorbing property because the gas tends to expand at room temperature so that a highly inflated piece of shock absorbing packaging material is formed as shown by section A of FIG. 10.

Although the horizontal welding links 28, 28 and the vertical welding links 30, 30 are shown here as rotating welding

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members are shown, various other designs of such welding members are provided. These welding links can be, for example, but not limited to, welding links which contain twin-rib devices and similar designs which permit the device described therein to be operated at high speed.

r ~

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4 sheets of drawings

Claims (11)

672 474 PATENT CLAIMS 1. A method for producing a shock absorbing packaging material body made of plastic film, having a plurality of bulbous units in which gas is contained, characterized in that plastic is formed into a tubular body, a first transverse end seal is formed around a leading end of the same a gas cooled to ambient temperature is introduced into a section of the tubular body behind the first transverse weld at a pressure between 98 and 980 Pa, that in the tubular body behind the first transverse end weld and at a distance therefrom a second transverse end weld parallel to or in a Angle is formed relative to the first end weld, whereby a hollow unit with gas trapped therein is formed between the first and second end weld that gas cooled to ambient temperature in a portion of the tubular body behind the second transverse end weld is introduced at a pressure between 98 and 980 Pa and a third transverse end weld is formed in the tubular body behind the second end weld and at a distance therefrom and parallel to or at an angle relative to the second end weld which is the angle between the first end weld and the second End weld corresponds, whereby a further hollow unit is formed between the second and third end weld, in which gas cooled at ambient temperature is trapped. 2. The method according to claim 1, characterized in that the first, second and third transverse end welding are formed by generating a welding pressure of 390 x 103 to 980 x 103 Pa. 3. The method according to claim 1, characterized in that the first, second and third transverse end welding are formed by welding at a temperature between 130 ° C and 180 ° C for 0.3 to 0.7 seconds. 4. The method according to claim 1, characterized in that the tubular body is formed from at least two plastic films that the transverse end welds for a period of 0.3 to 0.7 seconds, at a temperature between 130 ° C and 180 ° C and one Welding pressure between 390 x 103 and 980 x 103 Pa are formed, and that the gas with a temperature between 10 ° C and 20 ° C below ambient temperature is introduced into the respective section of the tubular body behind the respective transverse end weld. 5. The method according to claim 4, characterized in that the at least two plastic films have a total thickness of 9 to 30 microns. 6. The method according to claim 5, characterized in that the melting point of the second plastic film is between 230 ° C and 240 ° C, such that the second plastic film remains unmelted during the welding processes and maintains the web structure for the shock absorbing packaging material body. 7. The method according to claim 5, characterized in that one of the plastic films is a laminated film containing at least one layer of polyethylene terephthalate. 8. The method according to claim 7, characterized in that the second of the plastic films is a laminated film with at least one layer of low density polyethylene, a layer of high density polyethylene and a layer of polyethylene terephthalate, that the layer of low density polyethylene with a thickness in the range between 10 to 20 micrometers and a melting point in the range between 160 ° C to 180 ° C, that at least the layer of polyethylene terephthalate has a thickness in the range between 12 to 30 micrometers and a melting point in the range between 230 ° C to 240 ° C, such that during welding, at least the layer of low density polyethylene melts to adhere to the other of the plastic film and at least the layer of polyethylene terephthalate remains unmelted during welding to maintain a web-like structure for the shock absorbing body. 9. The method according to claim 5, characterized in that the molding of the plastic film includes a molding of three sheets of plastic into a tubular body, one sheet of low density polyethylene, a second sheet of high density polyethylene and a third sheet of polyethylene terephthalate. 10. The method according to claim 9, characterized in that during the melting processes, the web of low density polyethylene melts to connect the webs of low density polyethylene, high density polyethylene and polyethylene terephthalate. 11. The method according to claim 4, characterized in that the welding points are each at the same distance from one another.