GB2053794A - Method and apparatus for heat sealing or welding surfaces - Google Patents

Method and apparatus for heat sealing or welding surfaces Download PDF

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Publication number
GB2053794A
GB2053794A GB8023439A GB8023439A GB2053794A GB 2053794 A GB2053794 A GB 2053794A GB 8023439 A GB8023439 A GB 8023439A GB 8023439 A GB8023439 A GB 8023439A GB 2053794 A GB2053794 A GB 2053794A
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United Kingdom
Prior art keywords
sealing
heat
corona treatment
jaws
bags
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GB2053794B (en
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Linnich Papier & Kunststoff
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Linnich Papier & Kunststoff
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/76—Making non-permanent or releasable joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/02—Preparation of the material, in the area to be joined, prior to joining or welding
    • B29C66/028—Non-mechanical surface pre-treatments, i.e. by flame treatment, electric discharge treatment, plasma treatment, wave energy or particle radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/13—Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/131—Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/20—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines
    • B29C66/24—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight
    • B29C66/242—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours
    • B29C66/2424—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours being a closed polygonal chain
    • B29C66/24243—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours being a closed polygonal chain forming a quadrilateral
    • B29C66/24244—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours being a closed polygonal chain forming a quadrilateral forming a rectangle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/53—Joining single elements to tubular articles, hollow articles or bars
    • B29C66/534—Joining single elements to open ends of tubular or hollow articles or to the ends of bars
    • B29C66/5346—Joining single elements to open ends of tubular or hollow articles or to the ends of bars said single elements being substantially flat
    • B29C66/53461—Joining single elements to open ends of tubular or hollow articles or to the ends of bars said single elements being substantially flat joining substantially flat covers and/or substantially flat bottoms to open ends of container bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B29C66/712—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined the composition of one of the parts to be joined being different from the composition of the other part
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/723—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered
    • B29C66/7232—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered comprising a non-plastics layer
    • B29C66/72327—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered comprising a non-plastics layer consisting of natural products or their composites, not provided for in B29C66/72321 - B29C66/72324
    • B29C66/72328—Paper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/74—Joining plastics material to non-plastics material
    • B29C66/748—Joining plastics material to non-plastics material to natural products or their composites, not provided for in groups B29C66/742 - B29C66/746
    • B29C66/7486—Paper, e.g. cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/10—Surface shaping of articles, e.g. embossing; Apparatus therefor by electric discharge treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/08—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using ultrasonic vibrations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9141—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature
    • B29C66/91421—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature of the joining tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/919—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux characterised by specific temperature, heat or thermal flux values or ranges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/92—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools
    • B29C66/929—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools characterized by specific pressure, force, mechanical power or displacement values or ranges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/94—Measuring or controlling the joining process by measuring or controlling the time
    • B29C66/949—Measuring or controlling the joining process by measuring or controlling the time characterised by specific time values or ranges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2711/00—Use of natural products or their composites, not provided for in groups B29K2601/00 - B29K2709/00, for preformed parts, e.g. for inserts
    • B29K2711/12—Paper, e.g. cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2711/00—Use of natural products or their composites, not provided for in groups B29K2601/00 - B29K2709/00, for preformed parts, e.g. for inserts
    • B29K2711/12—Paper, e.g. cardboard
    • B29K2711/123—Coated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7128—Bags, sacks, sachets

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)

Abstract

In a method for the heat-sealing or welding of a surface consisting of an olefinic polymer to a surface consisting of a polar synthetic or cellulose material, the surface consisting of the olefinic polymer is firstly subjected to a corona treatment and the surfaces are subsequently joined under heat and pressure. Apparatus for closing containers or bags having surfaces of the aforedescribed materials, comprises conveying means for the containers or bags, sealing jaws for effecting the heat-sealing, and a corona for treating at least one of the sealing surfaces located upstream of the sealing jaws. The jaws may be heatable or may heat seal ultrasonically. Specified olefinic polymers are polyethylene, polypropylene and copolymers of ethylene or propylene with vinyl acetate or acrylic acid ester. The polar surface may consist of a polymer based on vinyl acetate or vinyl chloride, polyester, e.g. polybutylene terephthalate, or paper or cardboard with or without laquer or a pigment coating.

Description

SPECIFICATION Method and apparatus for heat sealing or welding surfaces The invention relates to a method for heat-sealing or welding surfaces consisting of olefinic polymers to surfaces consisting of polar synthetic or cellulose materials, in particular on containers, bags or the like, in which the surfaces are connected to each other with heating and under pressure.
It is known that thermoplastic surfaces can be heat-sealed or welded under the action of pressure and heat. Known examples of this are sealable bags consisting of plastics sheet or containers consisting of plastic-coated paper or cardboard, which are closed by heat-sealing. It is also known that a heat-sealed joint is possible between plastics sheet on the one hand and plastic-coated paper on the other hand.
When heat-sealing, it is generally true that the best joint is achieved if the thermoplastic synthetic materials to be sealed are of the same type, for example polyethylene to polyethylene or PVC to PVC. On the other hand, different types of synthetic material frequently cannot be joined. Thus it is known that polyethylene cannot be connected to PVC without an intermediate layer which is compatible with both synthetic material. The same is true for sealing joints between polyethylene and polypropylene. Also, a connection between polyester and olefinic polymer sealing conditions, namely if copolymers, so called ionomers, are used as the olefinic polymers.
It is the object of the present invention to propose a method of the aforedescribed type, which facilitates direct heat-sealing or welding between surfaces consisting of olefinic polymers and surfaces consisting of polar synthetic or cellulose materials.
According to the present invention there is provided a method for the heat-sealing or welding of a surface consisting of an olefinic polymer to a surface consisting of polar synthetic or cellulose material in which the surfaces are interconnected with heating and under pressure wherein before the connection the surface consisting of the olefinic polymer is subjected to a corona treatment.
Due to the process which is technically simple to carry out, of a treatment of the olefinic polymer surfaces to be sealed, by a corona, a good sealed joint can be produced between materials of this type, which hitherto could only be connected inadequately or not at all. The corona treatment involves subjecting the olefinic polymer surfaces to be sealed to an electrical high voltage alternating field.
Examples of olefinic polymer surfaces to which the invention may be applied are those comprised of polymers of ethylene or propylene. Alternatively the olefinic polymer may be a copolymer of ethylene or propylene with vinyl acetate or on acrylic acid ester.
The polar surface may be of a polymer based on vinyl acetate or vinyl chloride or alternatively may be of polyester.
It is already known to subject polyethylene surfaces, which are to be printed, to a corona treatment in order to influence the printing operation and the printed result favourably. It is known from this that, due to the corona treatment, the behaviour of polyethylene surfaces when sealed together is impaired. It is all the more surprising that the sealing behaviour of olefinic polymer surfaces to other types of synthetic material or to cellulose materials is influenced favourably as a result of the corona treatment so that bonds are achieved which were hitherto impossible.
Thus, for heat-sealing to a polyester surface, for example polybutylene terephthalate (PBT) it was previously necessary for example to use an ionomer, i.e. a copolymer of ethylene with acrylic or methacrylic acid, in order to achieve a bond. This ionomer is above all relatively expensive. However, due to the method according to the invention, polyethylene can be connected directly to polyester or PVC in a troublefree manner. A similar satisfactory bond is also possible with cellophane and paper. Also, troublefree heat-sealed joints are also possible due to the method according to the invention between olefin derivatives, such as ethylene vinyl acetate and other thermoplastic synthetic materials, for example PVC, polyester synthetic material (PBT) and paper.
Advantageously, surfaces consisting of polar synthetic or cellulose materials may also be subjected to the corona treatment.
It has also been found that the strength of the joint of the heat-sealing operation can be adjusted and controlled by the intensity of the corona treatment.
The intensity may be controlled either by varying the high voltage alternating field or the duration for which the surfaces to be treated are subject to the corona treatment. The more intensive the corona treatment, the firmer the sealed joint between the sealed surfaces.
Since the method according to the invention facilitates the heat-sealing of those olefinic polymers to other synthetic materials or cellulose materials, which hitherto could not be connected to each other, a much greater selection than previously of relatively inexpensive materials is available.
The welding or sealing may be carried out directly in an apparatusforfinishing and/or closing containers, bags or the like, which comprises a conveying device for the containers as well as sealing jaws for pressing the surfaces together, and effecting the heat-sealing and a corona for treating the sealing surfaces is located in the conveying direction in front of the sealing jaws. The sealing surfaces are treated by the corona directly before the heat-sealing operation. The jaws may be such as to effect the sealing ultra-sonically, or may be heatableto effect the sealing.
Experiments are described hereafter, which illustrate the success of the method according to the invention: Example 1 a) A paper coated with 30g/m2 low density polyethylene (density approximately 0.92) was treated by a corona after the extrusion-coating, so that the polyethylene surface had a wetting value of approximately 45 dyn/cm. This polyethylene-coated material was sealed to a polyamide sheet having a thickness of 40 F #in a sealing unit with the tempera- ture of the jaws at 1 60"C, for a sealing time of 1 second and with a sealing pressure of 5 kg/cm2. After cooling, the layers could only be separated by tearing the paper surface. A satisfactory bond had thus been produced.
b) The paper described under paragraph a) coated with polyethylene and treated on the polyethylene side by the corona was heat-sealed to a composite material, which consisted of paper, aluminium foil and a layer of PVC varnish on the aluminium foil, at a temperature of 180 C, for 1 second and at a pressure of 5 kg/cm2. After cooling, the bond between the polyethylene layer and the layer of PVC varnish was so strong that a separation of the materials was only possible by tearing the paper surface.
c) If tests a) and b) were carried under the same conditions with a polyethylene-coated paper, whereof the polyethylene layer had not been treated with a corona and had a wetting value of approximately 32 dyn/cm, then after the heat sealing operation, no bond is produced between the material layers. The layers can be separated easily.
Example 2 A paper which is coated with 25 g/m2 of an ethylene vinyl acetate copolymer with a proportion of approximately 10% vinyl acetate and was treated before the heat-sealing operation bya corona to give a wetting value of approximately 45 dyn/cm, was sealed to a polyester sheet having a thickness of 15 Z at a temperature of 180 C, for 1 second and at a pressure of 5 kg/cm2. After cooling, the bond between the materials could only be separated by tearing the paper fibres, whereas with a test for comparison with the same copolymer layer without corona treatment, no bond was produced.
Example 3 A paper coated with 30g/m2 low density polyethylene, whereof the polyethylene layer was treated with a corona to give a wetting value of approximately 40 dyn/cm, was connected in a sealing unit to a PVC sheet having a thickness of 200 it In this case, the sealing jaw adjacent the PVC sheet remained cold, the jaw adjacent the coated paper was set at a temperature of 180"C for a sealing time of 1 second and at a pressure of 5kg/cm2.
This produced a so called peel-sealing effect, i.e.
the material bond could be opened without tearing paper fibres, but had splitting resistance adequate for sealing a packaging (approximately 0.2 kg/15 mm).
In the accompanying drawings, the material joint able to be achieved by the method according to the invention is illustrated by way of an example: Figure 1 shows a synthetic material container in section, and Figure 2 shows the same synthetic material container in perspective illustration.
The container 4 intended for example for foodstuffs is a deep-drawn dish consisting of PVC, which is closed by a lid 1 consisting of a composite paper/foil structure. The composite structure comprises a layer 2 of paper, which supports a layer 3 of polyethylene. The polyethylene layer 3 is treated by a corona and then connected by heat-sealing in the region of the rim 6 to the sealing rim 5 of the PVC container 4. The polyethylene/PVC bond is only possible due to the corona treatment in a manner such that the lid 1 ensures a permanent tight closure of the container 4.
If the corona treatment of the polyethylene layer 2 does not take place directly at the time of manufacture of the lid material, it is possible to carry out the latter in the installation in which the container 4 is filled and closed. In known manner, an installation of this type comprises movable sealing jaws, which enclose the rim 6 of the lid 1 with the sealing rim 5 of the PVC container 4 located therebelow, and heatseal the latter. The filled containers 4 which are to be closed by the lid 1 are conveyed by a conveying device below the sealing jaws. The composite paper/polyethylene material for the lid is either supplied in the form of individual sheets or immediately before the sealing operation is cut from a continuous web and placed on the container.
According to the method of operation, either the polyethylene layer on the individual sheets for the lids is treated by a corona immediately before the latter are engaged and placed on the containers 4 or the corona treatment takes place on the web-like material before it is cut into individual lids. For this, a corona has to be installed in the installation in the conveying direction before the closing station for the container 4. Corona installations of the type to be used in this case are known and do not need to be described in detail. (see German OS 27 53711 and German OS 27 53 750).

Claims (15)

1. Methodforthe heat-sealing or welding of a surface consisting of an olefinic polymer to a surface consisting of polar synthetic or cellulose material in which the surfaces are interconnected with heating and under pressure wherein before the connection the surface consisting of the olefinic polymer is subjected to a corona treatment.
2. Method according to claim 1, wherein the olefinic polymer is a polymer of ethylene or propylene.
3. Method according to claim 1, wherein the olefinic polymers are copolymers containing ethylene, propylene, vinyl acetate or acrylic acid ester.
4. Method according to any one of claims 1 to 3, wherein the polar surface consists of a polymer based on vinyl acetate or vinyl chloride.
5. Method according to any one of claims 1 to 3, wherein the polar surface consists of polyester combinations.
6. Method according to any one of claims 1 to 3, characterised by the fact that the polar surface consists of paper or cardboard with or without lacquer or a pigment coating.
7. Method according to any one of claims 1 to 6, wherein the surfaces consisting of polar synthetic or cellulose materials are also subjected to a corona treatment.
8. Method according to any one of claims 1 to 7, wherein the corona treatment is carried out at the time of manufacture of the surfaces.
9. Method according to any one of claims 1 to 7, wherein the corona treatment is carried out immediately before the sealing operation.
10. Method according to any one of claims 1 to 9, wherein the intensity of the corona treatment is controlled depending on the desired strength of the heat-sealed joint.
11. Apparatus for closing containers, bags or the like by heat-sealing, which containers, bags or the like have a sealing surface consisting of an olefinic polymer to be heat-sealed to a surface consisting of a synthetic or cellulose material, the apparatus comprising means for conveying the containers, bags or the like and sealing jaws for pressing the sealing surfaces together and to effect said heat sealing, wherein corona for treating at least one of the sealing surfaces is located upstream of the sealing jaws.
12. Apparatus as claimed in claim 11 wherein the sealing jaws effect heat-sealing ultrasonically.
13. Apparatus as claimed in claim 11 wherein the jaws are heatable to effect said sealing.
14. Methodforthe heat-sealing orwelding of a surface substantially as hereinbefore described with reference to the accompanying drawings.
15. Apparatus for closing containers, bags or the like substantially as hereinbefore described.
GB8023439A 1979-07-21 1980-07-17 Method and apparatus for heat sealing or welding surfaces Expired GB2053794B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19792929617 DE2929617A1 (en) 1979-07-21 1979-07-21 METHOD FOR HOT SEALING OR WELDING SURFACES, ESPECIALLY ON CONTAINERS OR THE LIKE, AND DEVICE THEREFOR

Publications (2)

Publication Number Publication Date
GB2053794A true GB2053794A (en) 1981-02-11
GB2053794B GB2053794B (en) 1983-12-07

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8023439A Expired GB2053794B (en) 1979-07-21 1980-07-17 Method and apparatus for heat sealing or welding surfaces

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DE (1) DE2929617A1 (en)
FR (1) FR2461568A1 (en)
GB (1) GB2053794B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2494226A1 (en) * 1980-11-20 1982-05-21 Uni Charm Corp Package for individual hygiene items - made of bent resin film with edges held by adhesive or hot welding
WO1993010959A1 (en) * 1991-11-27 1993-06-10 Reckitt & Colman Products Limited Improvements in or relating to welding
FR2887487A1 (en) * 2005-06-27 2006-12-29 Solvay Ind Foils Man And Res PROCESS FOR SOLDING PLASTIC MATERIAL

Families Citing this family (2)

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Publication number Priority date Publication date Assignee Title
DE3343150A1 (en) * 1983-11-29 1985-06-05 Günter H. Dr.-Ing. 8035 Gauting Marx Process for heat-sealing layers, especially for closing containers
CN101941293B (en) * 2010-07-22 2013-01-02 金猴集团威海鞋业有限公司 Pattern processing method for polyurethane foam materials

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US3029175A (en) * 1957-01-04 1962-04-10 Akerlund & Rausing Ab Method of forming a blank of cellulosic material into a tubular carton
BE604957A (en) * 1961-02-28
US3184358A (en) * 1961-06-20 1965-05-18 Multifol Patentverwert Ag Method of forming laminated plastic tubing
GB1235347A (en) * 1967-12-20 1971-06-09 Jintan Terumo Company Ltd A method of enclosing an article in a container
US3597415A (en) * 1969-05-14 1971-08-03 Upjohn Co Erythromycin amides and process for preparing same
GB1473506A (en) * 1973-10-12 1977-05-11 Sidaplax Lids For Containers A production of lidded containers
US4028551A (en) * 1975-10-17 1977-06-07 Champion International Corporation Apparatus and method for corona discharge priming a dielectric web

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2494226A1 (en) * 1980-11-20 1982-05-21 Uni Charm Corp Package for individual hygiene items - made of bent resin film with edges held by adhesive or hot welding
WO1993010959A1 (en) * 1991-11-27 1993-06-10 Reckitt & Colman Products Limited Improvements in or relating to welding
AU661521B2 (en) * 1991-11-27 1995-07-27 Reckitt Benckiser (Uk) Limited Improvements in or relating to welding
FR2887487A1 (en) * 2005-06-27 2006-12-29 Solvay Ind Foils Man And Res PROCESS FOR SOLDING PLASTIC MATERIAL
WO2007000273A1 (en) * 2005-06-27 2007-01-04 Renolit Ag Method of welding plastics

Also Published As

Publication number Publication date
DE2929617A1 (en) 1981-02-12
FR2461568A1 (en) 1981-02-06
GB2053794B (en) 1983-12-07

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