THIN-WALLED CONTAINER AND LID, AND ALSO A METHOD FOR MAKING

Abstract: The invention relates to a thermoformed container of thin-walled plastic, with a material thickness (t) of between 0.1 and 2.0 mm, comprising a container part (1), with a bottom section (2) and a wall section (4), and a closure part (3), the closure part (3) comprising threads (5) and an annular sealing face (7). The container is characterized in that the free end (13) of the collar (10) has the largest diametrical dimension of the container. The invention also relates to a method for the manufacture of said container.

Description: THIN-WALLED CONTAINER AND LID, AND ALSO A METHOD FOR MAKING TECHNICAL FIELD The present invention relates to a container and a lid of thin- walled plastic, which are provided with screw threads. The invention also relates to a method of being able to produce such a container and such a lid cheaply. BACKGROUND Plastic is often a preferred material in connection with packagings, above all thanks to plastic's good barrier properties, i.e. the fact that it is impermeable. Another requirement of many packagings, primarily in the food industry, is that they must be liquid- tight in the closure between the lid and container. Liquid-tight plastic packagings of this kind are however relatively expensive if they are provided with threads. It is not possible to manufacture threaded plastic containers cheaply using the prior art. The reason for this is that according to the prior art, injection moulding is used to manufacture such containers. The tools for injection moulding are expensive and complicated to produce, since spark machining is necessary. As a consequence of this, it is attempted to avoid too much machining, which means that the material thickness is often permitted to be greater than the strength actually demands. In addition, in injection moulding joints are formed along the mould parts, joints which require that an extra pressing pressure must be able to be applied to the sealing face in order that the packaging shall not leak, which in turn also results in a need for material reinforcement. An increased material thickness naturally entails increased material consumption, which gives an increase in price. In many situations, one is forced owing to cost reasons to compromise with regard to the hermetic closing capacity of the plastic container, with the aim of obtaining a sufficiently low price. Plastic packagings for salads of various types are a typical example in which such a compromise is often made. Thus a plastic container with threads is not used here, but a plastic container closed by a lid with a snap-in fastener. The container and lid are manufactured from thin- walled plastic by means of thermo- forming, for example by means of vacuum technology. Containers of this kind occur very frequently thanks to their low price, which is a consequence of the fact that the tools for thermoforming are very cheap, as they can be manufactured by means of conventional, cheap machining methods, for example cutting. In addition, the starting material for the container is cheap and the material consumption low. The material thickness of the starting material is always less in principle than 0.9 mm and more often than not is as thin as approx. 0.3-0.4 mm. The disadvantage of such containers is that the sealing capacity, between a snap-in lid and the container, is not always reliable. Thus there is a risk of such containers leaking, above all when they are exposed to stress or when they are inclined or turned over, which is naturally a major disadvantage. As an example, US 5,628,417 shows a plastic container with a plastic lid, with a threaded closure, which is manufactured according to a conventional forming method, with separable mould parts. Both the container and lid will therefore be relatively thick- walled and will have edges/burrs which obstruct sealing in the areas of the joints between the mould parts. A threaded cap for a bottle is known from 4,099,903, which cap is manufactured by moulding of a plastic film on a tool. Following moulding, the tool is rotated so that the cap can be released from it. The shape of the cap is specially adapted for bottles, which bottles are manufactured according to other, known methods. ACCOUNT OF THE INVENTION The aim of the present invention is to eliminate or at least minimize the above problems, which is achieved by means of a container of thin- walled plastic, comprising a container part, with a bottom section and a wall section together with a closure part, the closure part comprising threads. By means of the method used for manufacturing the container, the great advantage is gained that an impermeable container with hermetically closing lid can be manufactured at very low cost in relation to existing plastic containers. In addition, they can be manufactured in a recyclable material and are easy to compress following use, which are further advantages. Further aspects of the container according to the invention are that: - the material thickness is between 0.1 and 2.0 mm, and the material thickness of the threads is essentially the same as the material thickness of the container, - the closure part comprises a sealing face, which is devoid of discontinuities. A major advantage of a container according to the invention is that, thanks to the method of manufacture, the sealing face is completely smooth, in contrast to containers which are produced by means of other methods, for example mould blowing, die casting, in which a discontinuity is always formed in the parting line between the mould parts. Thanks to the invention, a smooth sealing face is thus ensured without edges/burrs. Further aspects are that: - the sealing face is arranged rotationally symmetrically around an axis of symmetry, - the normal to said sealing face is disposed essentially parallel to said axis of symmetry, - said threads are arranged in a collar in the upper part of the container, - each sectional face through the collar parallel to the line of symmetry preferably comprises at least one thread ridge, - the free end of the collar has the largest diametrical dimension of the container, - said collar forms a section directed downwards, the uppermost face of the container consisting of material which lies between the collar section and the container part, - the sealing face, in one embodiment, consists of the uppermost face of the container, - the collar part is threaded externally to receive a lid, and it encloses the sealing face, together with preferably an upper part of the wall section, a stiffening closure part being formed, - said collar, in one embodiment, is threaded internally to receive a lid, and the collar forms a section directed upwards, so that it constitutes an extension of the container, - the sealing face is, in one embodiment, arranged on a sealing ridge, preferably between said wall section and an upper wall section, the wall section preferably passing in the main directly into the sealing ridge. The invention also relates to a lid of thin- walled plastic, comprising a closure part and a lid part with an underside and an upper side, the closure part comprising threads. Further aspects of a lid according to the invention are that: - the material thickness is between 0.1 and 2.0 mm, and the material thickness of the threads is essentially the same as the material thickness of the lid part, - the closure part comprises a sealing face arranged in a transition zone between the lid part and the closure part, - the sealing face is arranged rotationally symmetrically around an axis of symmetry, - said sealing face consists of an annular section, which projects below the underside of the lid part, at least in the area adjacent to said annular section, so that a transition zone is formed, which produces stiffening, - the closure part comprises a wall section, which extends essentially vertically and the lower end of which passes in the main directly into said annular section, - said wall section extends a substantial distance between said annular section and the upper part of the lid, - the threads are arranged in a collar which extends downwards from said upper part, and which at a distance encloses said wall section, - the sealing face consists, in one embodiment, of an annular section, which projects outside, and preferably above, the underside of the lid part. The invention also relates to a container of thin- walled plastic, comprising a container part, with a bottom section and a wall section, together with a closure part, the closure part comprising threads, with a lid of thin- walled plastic, comprising a closure part and a lid part with an underside and an upper side, the closure part comprising threads which correspond to the threads in the closure part of the container. Further aspects of a container with a lid according to the invention are that: - the lid and container each have a lug, which is intended for welding together, - a perforation line is provided to be able to tear off said lugs, - the wall section of the lid has a smaller outward inclination relative to the vertical plane than a corresponding wall section of the container, - the wall section of the lid, in another embodiment, has the same outward inclination relative to the vertical plane as a corresponding wall section of the container, - the wall section of the lid has a longer vertical extension than a corresponding wall section of the container, due to which the lid can be screwed onto the container so that said annular section of the lid is pressed together with the sealing face of the container. The invention also relates to a method of manufacture of the container and/or lid according to the above, thermofoπning being used, a thin- walled plastic material being used as the starting material. Further aspects of a method according to the invention are that: - a vacuum or pressure is used in connection with manufacture, - the ready-formed pieces are first punched and then rotated out of the forming tool, either by: - disposing the forming tool to be rotatable, or by - disposing a gripping device for gripping the container or lid to be rotatable, - arranging the threaded part of each form in the forming tool rotatably, so that the pieces can be ejected from the tool by said part being rotated, the ready-formed pieces being lifted up out of the form vertically straight up, - ejecting the finished pieces from the material in sheet form following ejection from the forming tool. DESCRIPTION OF DRAWING The invention will be described below with reference to the figures, in which: Fig. 1 shows a container according to a preferred embodiment of the invention, Fig. 2 shows a lid according to a preferred embodiment of the invention, Fig. 3 shows the container in Fig. 1 with the lid in Fig. 2, Fig. 4 shows an alternative lid for the container in Fig. 1, Fig. 5 shows a container with a lid according to a second embodiment of the invention, Fig. 6 shows a container with a lid according to a third embodiment of the invention, Fig. 7 shows a container with a lid according to a fourth embodiment of the invention, Fig. 8 shows a container with a lid according to a fifth embodiment of the invention, Fig. 9 shows a container with a lid according to a sixth embodiment of the invention, Fig. 10 shows a container with a lid according to a seventh embodiment of the invention, Fig. 11 shows an alternative execution, which is specially intended for large pots, a container with a lid being shown in principle from the side, Fig. 12 shows a container with lid according to Fig. 11 seen from above, and Fig. 13 shows an alternative execution, in principle according to Fig. 11, but also intended for smaller pots. DETAILED DESCRIPTION Fig. 1 shows a thin- walled container with a container part 1, an essentially level bottom section 2 which passes via a corner area into a wall section 4, together with a closure part 3. The material for the container is synthetic, preferably a polymer material, and even more preferredly a preferably recyclable plastic material, e.g. polystyrene, polypropylene, polyethylene, polyethylene terephthalate, or polyvinyl chloride. The criteria for the choice of material are that the material shall be suitable for thermo- forming under pressure or vacuum, and that it shall be approved for use in packagings for food, medicines etc., at least in cases where such application areas are current. The container is thin-walled, with a material thickness (t). According to the invention, the closure part 3 comprises threads 5. In the preferred embodiment shown in Fig. 1, the threads 5 are arranged in a collar 10 in the upper section of the container. The collar here forms a section directed downwards which, at a distance, encloses the upper part of the container part 1, due to which the closure part 3 forms a stiffening section for the container. Between the collar 10 and the container part 1 is the uppermost face 12 of the container, which face can be level and mainly horizontal, or can form an acute angle between the collar 10 and the container part 1. The threads 5 are hollow, since the container is manufactured by meιτnoforming, which means that the hollow reverse sides of the threads are visible on the inside/reverse of the collar. Due to this, the threads 5 are also deformable to a certain extent, which can be positive for the fit and sealing between the container and lid. The threads 5 are arranged such that each imaginary sectional face through the collar 10 and parallel to a line of symmetry 9 usually comprises at least one thread ridge 5A. However, in certain cases the threads can be distributed in such a way that certain cross-sections do not pass through any thread ridge. Between the thread ridges 5 A the collar 10 has a smaller diameter 5B. The free end 13 of the collar has the greatest diameter of the container. In the main, the container is, except for on the threads 5, rotationally symmetrical (which is not however necessary) around the axis of symmetry 9. The closure part 3 also has an annular sealing face 7, which is continuously smooth or devoid of discontinuities. In the preferred embodiment, the sealing face 7 is arranged rotationally symmetrically around the axis of symmetry 9 and has a normal which is essentially parallel to the axis of symmetry. The sealing face 7 is also disposed between the wall section 4 of the container part 1 and an upper wall section 14, which upper wall section 14 has a greater diameter than the wall section 4. Fig. 2 shows the lid 20 for the container in Fig. 1. The material in the lid is preferably the same as in the related container. The lid 20 comprises a closure part 22, which is provided in a collar-like section with internal threads 26, corresponding to the threads 5 in Fig. 1 , and an essentially level lid part 24 with an underside 24A and an upper side 24B. The closure part 22 also comprises an annular section/a sealing face 28 which is continuously smooth or devoid of discontinuities and is arranged in a transition zone 30 between the lid part 24 and the closure part 22. Both the lid part 24 and the sealing face 28 are disposed rotationally symmetrically around an axis of symmetry 9. The sealing face 28 consists of an annular section which projects, i.e. forms a sealing ridge, below the underside 24A of the lid part. This construction provides rigidity at the same time as it leads to effective sealing between the sealing face 28 of the lid and the corresponding sealing face 7 of the container. The closure part 22 also comprises an essentially vertical wall section 32, which is arranged rotationally symmetrically around the axis of symmetry 9 and arranged concentrically inside the outer, collar-like, threaded part of the closure part, with the lid's uppermost part 34 in between. The wall section 32 passes advantageously directly into the annular section/sealing face 28, i.e. so that the lower part of the wall section will form one side wall in the sealing ridge. It is also advantageous here that the wall section 32 is mainly smooth, i.e. without deformation notches, a closing force being able to be led directly down into the sealing face 28, when a container is closed with the lid 20. Fig. 3 shows the container according to Fig. 1 with the lid according to Fig. 2, with a couple of aspects which are important for sealing to be emphasized. The wall section 32 of the lid has a radius smaller than that produced by the corresponding, upper wall section 14 of the container on the corresponding vertical distance. This means that, when the lid is applied to the container, a gap 40 is formed between the wall sections 32 and 14, which facilitates fitting of the lid 20 on the container 1. Complete sealing is achieved by means of the sealing faces 7 and 28, when the lid 22 presses these against one another by means of its threads 26 interacting with the threads 5 of the container 1. For the sealing faces 7 and 28 to seal fully against one another, the wall section 32 of the lid has a longer vertical extension than the corresponding upper wall section 14 of the container, due to which the lid can be screwed so far down onto the container that the sealing face 28 of the lid is pressed together with the sealing face 7 of the container, without any risk that the upper edge 12 of the container shall come into contact with the corresponding part 34 of the lid 20. Fig. 4 shows an alternative lid 20 for the container in Fig. 1, which lid is formed so that the annular section 28, i.e. the sealing face 28 of the lid, projects below the underside 24A of the lid only in the area adjacent to the annular section. The remaining part of the lid's underside 24A, i.e. the more centrally oriented section, is arranged on the other hand at a level which lies below the annular section 28. Fig. 5 shows a second embodiment of the lid and container, in which the annular section/sealing face 7 of the container 1 has a sealing ridge, the inner side wall of which passes directly into the wall section 4 of the container part. In this embodiment, the lid 20 on the other hand has a level sealing face 28 with a normal which is disposed parallel in the main to the axis of symmetry 9. It is naturally also conceivable that both the container and the lid have sealing ridges arranged against one another. This figure also illustrates that it is possible to arrange the lid and container without any gap between their adjacent, essentially vertical wall sections 14, 32. Fig. 6 shows a third embodiment of the lid and container, in which the container is formed with a wall section 4 which passes into a bottom section 2, which bottom section is essentially rounded, i.e. the container lacks an essentially level bottom section. The embodiment is intended thereby to illustrate that the overall shape of the container is not of importance to the invention. It is also evident from Fig. 6 that complete sealing between the lid and container can be obtained when the wall section 32 of the lid has a smaller outward inclination relative to the axis of symmetry 9 than that produced by the container's corresponding wall section 14A on the corresponding vertical distance. This means that, when the lid is applied to the container, a gap 40 tapering downwards is formed, the wall sections 32 and 14A being pressed together at the bottom increasingly the further down the lid is screwed onto the container. This sealing variant is naturally not limited to containers with non-level bottoms. An advantage of having a difference in inclination between adjacent wall sections connected to the sealing face is that a premature sealing interaction can thereby be avoided when the lid is applied, so that excess pressure in the container can easily be avoided. It is best to have a larger distance between the upper edge 12 of the container and the lid 34, as in Fig. 3, so that less precision is required in manufacturing and better flexibility is also otherwise obtained, except in those cases when double sealing is desired. Fig. 7 shows a fourth embodiment of the lid and container, in which the collar 10 of the container forms a section directed upwards, so that it constitutes an extension of the container. The collar 10 is here internally threaded to receive a lid. The collar 10 has a greater diameter than the wall section 4 and the sealing face 7 is disposed in between in the same way as in Fig. 1. The collar 10 can also (not shown) have a section directed downwards, which encloses the threaded part at a distance. The lid 20 is threaded externally, but nevertheless has a collar-like part 39, which is directed downwards from the upper part 34 of the lid and which encloses the threaded part at a distance, for the sake of stiffening and gripping ability. In this embodiment also the lid 20 has a wall section 32, the lower end of which passes in the main directly into the annular sealing part 28. Fig. 8 shows a fifth embodiment of the lid and container, in which the sealing face 7 of the container consists of the uppermost face 12 of the container. An upper wall section 14 is thereby lacking above the sealing face. The collar 10 is otherwise formed in the same way as in Fig. 1. On the lid 20, the sealing face 28 consists of an annular section, which is positioned radially outside, and preferably above, the underside 24A of the lid part. The sealing face 7 of the container has a sealing ridge, the inner wall of which passes directly into the wall section 4. The wall section 32 provides stiffening, which in certain cases is necessary for sealing between the container and lid to remain satisfactory. Fig. 9 and 10 show two further embodiments for obtaining sealing between the lid 20 and container 1 at the uppermost face 12 of the lid. In Fig. 9, this is achieved by disposing an annular groove 41 in the surface 12 of the container 1. The lid 20 is provided in a corresponding manner with an annularly projecting part 43, which on threading in is intended to be pressed into the groove 41 , two annular sealing sections being obtained, since the wall sections in the groove 41 and the projecting part 43 respectively are somewhat inclined. In addition, a similar sealing face is obtained in the transition between the upper face 12 of the container and its wall section 4, where the downwardly directed wall section 32 of the lid will lie. In Fig. 10, sealing is achieved by the lid 20 being provided in its upper annular face 34 with a projecting part 45 intended to interact with the upper face 12 of the container part, which also forms the actual sealing face. Fig. 11 and 12 show that the container 1 and lid 10 can be formed with a small lug 47 A, 47B each at their free edges, the positioning of the lugs being adapted so that they lie right before one another when the container is closed. The two lugs can then be sealed to one another by e.g. welding, a seal being formed on the container. The two lugs can also have a perforation line 49 to facilitate opening of the seal. Furthermore, Fig. 11 and 12 show that larger pots can be provided advantageously with twist grips 51, 53. The twist grip 51 in the lid part 20 is formed as a number of projecting devices, which form a kind of bubbles 51. Four such bubbles 51 are best affixed in the lid part. The opening and closing direction respectively for the lid are also preferably impressed. In a corresponding manner, cavities 53 are disposed in the bottom section 2 of the container 1, which form twist grips. Both the bubbles 51 and the cavities 53 are adapted in terms of size to be ergonomically correct for being gripped by means of the fingers. Fig. 13 shows a variant of a container 1 with a lid 20, formed with twist grips 51, 53, in accordance with the principles which are evident from Fig. 11 and 12. This execution is however intended more for smaller containers, the twist grips 51, 53 not being executed as separate elements but at best on the lid consisting of an elongated ridge-shaped part, which extends diametrically a substantial distance of the lid's diameter and the twist grip 53 in the bottom section of the container 1 consisting correspondingly of an elongated recess, which also extends a substantial part of the diametrical distance, so that the ridge 51 can be gripped with a thumb-finger grip and the recess 53 by one or more fingers being placed inside this, following which the lid can simply be screwed up. Furthermore, it is shown that with a form of this kind, no gripping collar around the threaded closure is necessary. Thus it is shown in the figures that the upper surface 34 of the lid part also constitutes its outermost part. The seal 7, 28 between the container 1 and lid 20 is altogether formed essentially in accordance with what is shown in Fig. 3, and is thus also arranged rotationally symmetrically in this execution. It is shown that the outer edge of the lid and the outer edge of the container part are disposed coaxially, which can be an advantage in certain circumstances. As already described earlier, the container and lid are manufactured by thermoforming, which is a very cost-effective method. In connection with memiofoπning, also for cost reasons, a tool is designed commercially in such a way that a number of articles can be manufactured simultaneously. Thus a relatively large sheet is fed to the tool, which after suitable heating is moved forward to the tool containing a multiplicity of forms, following which the plastic sheet is sucked in by means of a vacuum, for example, and takes on the contours according to the respective form. Thanks to the forming method, optimal material utilization is achieved, i.e. roughly the same material thickness is obtained overall. It should however be understood that a certain thinning/displacement of material can occur, for example comer areas often have a somewhat smaller material thickness (often approx. 20% smaller) than sections close by, since the corner sections are furthest away from the sheet at the start of forrning. This phenomenon can however be more or less eliminated in a known manner by means of special auxiliary tools, which displace the plastic material in the desired manner on forming. Following this, a certain cooling takes place to stabilize the shaped article. In the next stage, the sheet with the formed articles is ejected from the forming tool to be moved to the subsequent punching operation. Ejection from the forming tool is normally effected by means of so-called ejectors, which are separate units interacting with the forming tool. According to the present invention, said ejector tools can be eliminated by using the threads to eject the sheet. This is carried out by rotating the threaded part of each form in the forming tool. This can be achieved either by rotating the entire form area or by only rotating the threaded part. The advantage of only rotating the threaded part is that the container part 1 can then be allowed to assume shapes which are not rotationally symmetrical, for example a hexagonal shape, which results in a certain stiffening. To produce articles according to Figures 11 - 13, it is necessary to rotate only the threaded part, since the twist grip parts 51, 53 do not permit rotational symmetry. Furthermore, the advantage is gained that an ejector mechanism according to the above-named principle gives a very large contact surface for the ejector mechanism, so that great force can be transmitted at the moment of ejection without the article being damaged. Due to this, the possibility is offered according to the invention of being able for example to manufacture products which lack clearance, i.e. certain parts of the article can have entirely parallel walls (for example be absolutely cylindrical) or even have a sectional face diverging in direction towards the form. This cannot normally be done, since great ejection force is then required. No risk of damage exists, since on the one hand the plastic material is still slightly warm and the thin plastic material in itself is elastic. In certain cases, good sealing between the container and lid can cause a slight excess pressure to be formed inside the container when it is closed, in which case the container may acquire a slightly swollen appearance. So that this is not interpreted as the contents of the container having fermented, the bottom section can be formed curved slightly inwards from the start, so that it becomes more level when the container is closed. Alternatively, the container can be placed on an upwardly curving, supporting base when it is closed. The invention is not restricted to the embodiments shown, but can be varied within the scope of the following claims. It is perceived for example that the number of thread ridges can be varied within wide limits, all the way from one to a multiplicity. Furthermore, it is perceived that many conceivable shapes other than hexagonal containers 1 can be manufactured according to the method according to the invention, for example triangular, star-shaped etc. In addition, it is perceived that the collar can be arranged to extend a substantial distance, it being possible in an extreme case, with a downwardly directed collar, that the threads would be able to be arranged around the lower part of the container.

Claims: CLAIMS 1. Thermoformed container of thin- walled plastic, with a material thickness (t) of between 0.1 and 2.0 mm, comprising a container part (1), with a bottom section (2) and a wall section (4), and a closure part (3), the closure part (3) comprising threads (5) and an annular sealing face (7), characterized in that the free end (13) of the collar (10) has the largest diametrical dimension of the container. 2. Thermoformed container according to claim 1, characterized in that the material thickness for the threads (5) is essentially the same as the material thickness for the container part (1). 3. Thermoformed container according to claim 1 , characterized in that said annular sealing face (7) is devoid of discontinuities. 4. Thermoformed container according to claim 3, characterized in that the sealing face (7) is disposed rotationally symmetrically around an axis of symmetry (9). 5. Thermoformed container according to claim 4, characterized in that the normal to said sealing face (7) is arranged essentially parallel to said axis of symmetry (9). 6. Thermoformed container according to claim 1 , characterized in that said threads (5) are arranged in a collar (10), preferably arranged in the upper section of the container. 7. Thermoformed container according to claim 6, characterized in that essentially each sectional area through the collar (10) parallel to the line of symmetry (9) comprises at least one thread ridge (5a). 8. Thermoformed container according to claim 6, 7 or 8, characterized in that said collar (10) forms a section directed downwards, the uppermost face (12) of the container consisting of material which lies between the collar section (10) and the container part (2, 4). 9. Thermoformed container according to claims 3 and 8, characterized in that the sealing face (7) consists of the uppermost face (12) of the container. 10. Thermoformed container according to claims 3 and 8, characterized in that the collar section (10) is externally threaded to receive a lid, and that it encloses the sealing face (7) and preferably an upper part of the wall section (4), a stiffening closure part (3) being formed. 11. Thermoformed container according to claim 6, characterized in that said collar (10) is internally threaded to receive a lid, and that it forms a section directed upwards, so that it forms an extension of the container. 12. Thermoformed container according to claim 4, characterized in that the sealing face (7) is arranged on a sealing ridge, preferably between said wall section (4) and an upper wall section (14). 13. Thermoformed container according to claim 12, characterized in that the wall section (4) passes in the main directly into the sealing ridge. 14. Thermoformed lid (20) of thin- walled plastic, with a material thickness (t) of between 0.1 and 2.0 mm, and for a container according to claim 1, comprising a closure part (22) and a lid part (24) with an underside (24a) and an upper side (24b), the closure part (22) comprising threads (26), characterized in that the closure part (22) comprises a wall section (32) arranged inside said threads (26), which wall section extends downwards from an upper face (34) of the lid. 15. Thermoformed lid according to claim 14, characterized in that the material thickness of the threads (5) is essentially the same as the material thickness for the lid part (24). 16. Thermoformed lid according to claim 14, characterized in that the closure part (22) comprises a sealing face (28) arranged in a transition zone between the lid part (24) and the closure part (22). 17. Thermoformed lid according to claim 16, characterized in that the sealing face (28) is arranged rotationally symmetrically around an axis of symmetry (9). 18. Thermoformed lid according to claim 17, characterized in that said sealing face (28) consists of an annular section, which projects below the underside (24a) of the lid part, at least in the area adjacent to said annular section (28), so that a transition zone (30) is formed, which creates stiffening. 19. Thermoformed lid according to claim 18, characterized in that said wall section (32) passes in the main directly into said annular section (28). 20. Thermoformed lid according to claim 19, characterized in that said wall section (32) extends a substantial distance between said annular section (28) and the upper part (34) of the lid. 21. Thermoformed lid according to claim 20, characterized in that the threads (26) are arranged in a collar, which extends downwards from said upper part (34), and which at a distance encloses said wall section (32). 22. Thermoformed lid according to claim 16, characterized in that said sealing face (28) consists of an annular section, which projects outside, and preferably above, the underside (24a) of the lid part. 23. Thermoformed container according to any of claims 1-13, characterized by a lid according to any of claims 14-22. 24. Thermoformed container according to claim 23, characterized in that the lid and container are each provided with a lug (47A, 47B), which is intended for welding together. 25. Thermoformed container according to claim 24, characterized by a perforation line (49) for being able to tear off said lugs (47 A, 47B). 26. Thermoformed container according to claim 5, with a lid according to claim 19, characterized in that the wall section (32) of the lid has a smaller outward inclination relative to the vertical plane than a corresponding wall section (14) of the container. 27. Thermoformed container according to claim 5, with a lid according to claim 19, characterized in that the wall section (32) of the lid has the same outward inclination relative to the vertical plane as a corresponding wall section (14) of the container. 28. Thermoformed container with lid according to claim 26, characterized in that the wall section (32) of the lid has a longer vertical extension than a corresponding wall section (14) of the container, due to which the lid can be screwed onto the container so that said annular section (28) of the lid is pressed together with the sealing face (7) of the container. 29. Method for the manufacture of a container and/or lid according to any of the above claims, characterized in that thermofo-ming is used, a thin-walled plastic material in sheet form being used as the starting material. 30. Method according to claim 29, characterized in that a vacuum or pressure is used in connection with manufacture. 31. Method according to claim 30, characterized in that the ready-formed pieces are first punched and then rotated out of the forming tool. 32. Method according to claim 29, characterized in that the threaded part of each form in the forming tool is disposed rotatably, so that the ready-formed piece(s) can be ejected together with the sheet from the tool by said part being rotated, the ready- formed piece being lifted straight up out of the form. 33. Method according to claim 32, characterized in that the finished piece is punched out of the material in sheet form following ejection from the forming tool.

Inventors: LJUNGQVIST CHRISTER, PHIL GERHARD, LJUNGQVIST, CHRISTER, PHIL, GERHARD
Applicants: LJUNGQVIST CHRISTER, PHIL GERHARD, LJUNGQVIST, CHRISTER, PHIL, GERHARD
Application year: 2000
Main classification: B65D41
IPC codes: B65D1, B65D43