GB2027390A - Welding of plastics materials - Google Patents

Welding of plastics materials Download PDF

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Publication number
GB2027390A
GB2027390A GB7830506A GB7830506A GB2027390A GB 2027390 A GB2027390 A GB 2027390A GB 7830506 A GB7830506 A GB 7830506A GB 7830506 A GB7830506 A GB 7830506A GB 2027390 A GB2027390 A GB 2027390A
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GB
United Kingdom
Prior art keywords
heat
welding
sheet materials
materials
sheet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB7830506A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pike R A
Original Assignee
Pike R A
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pike R A filed Critical Pike R A
Priority to GB7830506A priority Critical patent/GB2027390A/en
Publication of GB2027390A publication Critical patent/GB2027390A/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
    • B32B37/16—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with all layers existing as coherent layers before laminating
    • B32B37/20—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with all layers existing as coherent layers before laminating involving the assembly of continuous webs only
    • B32B37/203—One or more of the layers being plastic
    • 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
    • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated 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
    • 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
    • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
    • B29C65/24—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools characterised by the means for heating the tool
    • B29C65/242—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools characterised by the means for heating the tool the heat transfer being achieved by contact, i.e. a heated tool being brought into contact with the welding tool and afterwards withdrawn from it
    • 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
    • B29C66/1122—Single lap to lap joints, i.e. overlap 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
    • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
    • B29C66/43—Joining a relatively small portion of the surface of said articles
    • 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
    • B29C66/729—Textile or other fibrous material made from plastics
    • 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
    • B29C66/73—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/731—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the intensive physical properties of the material of the parts to be joined
    • B29C66/7311—Thermal properties
    • B29C66/73115—Melting point
    • 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
    • B29C66/73—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/731—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the intensive physical properties of the material of the parts to be joined
    • B29C66/7311—Thermal properties
    • B29C66/73115—Melting point
    • B29C66/73116—Melting point of different melting point, i.e. the melting point of one of the parts to be joined being different from the melting point 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
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • 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
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81427—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined comprising a single ridge, e.g. for making a weakening line; comprising a single tooth
    • 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
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/832—Reciprocating joining or pressing tools
    • B29C66/8322—Joining or pressing tools reciprocating along one axis
    • 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
    • B29C66/91—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
    • B29C66/9192—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 in explicit relation to another variable, e.g. temperature diagrams
    • B29C66/91921—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 in explicit relation to another variable, e.g. temperature diagrams in explicit relation to another temperature, e.g. to the softening temperature or softening point, to the thermal degradation temperature or to the ambient temperature
    • B29C66/91931—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 in explicit relation to another variable, e.g. temperature diagrams in explicit relation to another temperature, e.g. to the softening temperature or softening point, to the thermal degradation temperature or to the ambient temperature in explicit relation to the fusion temperature or melting point of the material of one 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
    • 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
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/812—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B29C66/8124—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the structure of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B29C66/81241—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the structure of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps being porous or sintered
    • 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
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81411—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined characterised by its cross-section, e.g. transversal or longitudinal, being non-flat
    • B29C66/81421—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined characterised by its cross-section, e.g. transversal or longitudinal, being non-flat being convex or concave
    • B29C66/81422—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined characterised by its cross-section, e.g. transversal or longitudinal, being non-flat being convex or concave being convex
    • 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
    • B29C66/93—Measuring or controlling the joining process by measuring or controlling the speed
    • B29C66/934—Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed
    • B29C66/93431—Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed the speed being kept constant over time
    • 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
    • B29C66/93—Measuring or controlling the joining process by measuring or controlling the speed
    • B29C66/939—Measuring or controlling the joining process by measuring or controlling the speed characterised by specific speed 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
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • 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
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene
    • 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
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
    • B29K2105/20—Inserts
    • B29K2105/206—Meshes, lattices or nets
    • 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
    • B29K2313/00—Use of textile products or fabrics as reinforcement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2305/00—Condition, form or state of the layers or laminate
    • B32B2305/38—Meshes, lattices or nets

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Plasma & Fusion (AREA)
  • Textile Engineering (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)

Abstract

In a method for securing plastic sheet materials together by welding process heat is applied to the sheet at or about a temperature which is the flow or melting point temperature of one of the materials for a length of time sufficient to enable flow of the material at the point of application of heat to take place. Apparatus in accordance with the invention for such welding includes a welding tool (7) which is secured to a heat bank (5) and provides for substantially parallel heat pathes from the heat bank to the welding surface of the welding tool. <IMAGE>

Description

SPECIFICATION Welding of plastics materials This invention relates to the welding of plastics materials and particularly to the continuous welding of plastics materials in the form of sheets including continuous sheet materials and materials having a net like structure.
In the fabrication of articles from plastics sheet materials, that is articles such as bags and other recipients, there is normally a requirement for at least one welding operation to take place between superimposed layers of the plastics materials. However, it has proved very difficult to obtain a satisfactory weld in this situation without the use of expensive and complicated machinery and processing methods. The simplest form of welding is obtained by the application of heat to the materials concerned so that flow of the materials at the point of application occurs so that the weld is formed.
However, the majority of plastics materials used in the fabrication of articles as discussed above react very noticeably and undesirably to temperatures relatively close to but above the melting point of the material concerned. Such reactions may take the form of crinkling or of stretching of the plastics sheet materials and, sometimes, the unwanted physical separation of the material at the point of application of heat. As a result, there has been a tendency to avoid the use of direct heat application inethods and to turn to alternative methods such as ultrasonic methods and the use of laser beams to obtain the heating along the weld line and the subsequent welding. The alternative methods do however require substantial outlay in machinery and there are also serious problems which arise from the use of sophisticated and potentially dangerous apparatus.
The present invention is based on the suprising discovery that the direct application of heat to the plastics sheet materials to be welded together is entirely feasible and possible if specific conditions are recognised and met.
In accordance with the present invention there is provided a method of securing superimposed layers of plastics sheet material pressed together which comprises applying heat to at least one of sheets at or about a temperature which is the flow point or melting point temperature of one of the materials of the plastics sheet materials for a length of time sufficient to enable flow of the material at the point of application of the heat to take place so as to effect securing of the sheet materials together.
Preferably, the heat is applied directly to the region to be welded and the remaining material is held at a temperature substantially below the said temperature. That is, it is preferred that the original source of heat be shielded from the material which is not to be welded and that the heat be transferred from the source to the welding region by means which prevent the transfer of heat to the remaining material as efficiently as possible.
Where dissimilar materials are involved in the welding process, if both materials are in sheet form and one has a lower melting or flow point temperature than the other material then the softening of the lower melting point temperature material may well make it sufficiently tacky that the other material adheres thereto and becomes firmly secured thereto on cooling of the two materials after the welding operation. Alternatively, the two materials may have dissimilar physical structure in that one is a continuous sheet whereas the other is a sheet of mesh like material (or net like material). If the continuous sheet material has the lower flow point temperature then this material may flow around the elements of the net construction and serve to lock these in position on cooling of the material.
The invention may readily be applied to processes of continuous welding. In such processes the sheet materials are moved continuously along a path and the welding operation is carried out as required on the materials as they pass the welding position. Since, however, in accordance with the invention only low temperatures are to be applied to the materials, it is necessary for the materials to be in contact with the welding tool for a sufficient time to ensure the transfer of sufficient heat to the materials to obtain a satisfactory welding or other securing operation.This can be obtained either by having the sheet pass at a relatively slow rate across a welding tool or by making the welding tool of a substantial length in the direction of movement of the sheet materials so that the sheet material may be passed at a relatively high rate across the welding tool but because of the length of the welding tool, it remains in contact with the welding tool for a substantial length of time sufficient to obtain the desired strength of weld or other securing condition. In another method in accordance with the invention of obtaining a satisfactory weld when the sheet is moving continuously, it is possible to move the welding tool with the sheet for a limited but discrete length of movement of the sheet material.
Another aspect of the invention involves the provision of a substantial heat source. In this context it is meant that the heat supplied to the welding tool is derived from a form of heat bank which ensures that heat is constantly available at the welding tool at a temperature as required. Thus, it is preferable in accordance with the invention that the heat be supplied from a substantial metallic element which is heated by electrical resistance or other means the heat is transferred from this substantial metallic element by way of welding tools which are metallic and are constructed so as to provide uniform heat to the whole length of the welding tool having regard to the welding direction.
The particular temperatures required of the welding tool and the time for heat application will depend intrisically on the particular materials which are to be welded and on their thicknesses.
However, by way of example only there are indicated in Table I a variety of combinations which have proved satisfactory in practice.
TABLE I
Melting or Welding Length of Material Flow Point Surface Speed of Welding Type and Temperature Temperature Sheet Surface Thickness (oC) (etc) (mm/sec) (mm) Polypropylene film (30 ,am) 168 147-160 1000 5 Polyethylene film (125 ,am) 135 160 300 50 Polyethylene Polyethylene film (125 pm) 135 201 1500 50 Polypropylene net (125 #Lm) 168 160 120 25 Polypropylene net (125 ,am) 168 175 900 25 It is necessary to take steps to keep the materials being welded in contact with the welding tool during the time of application of heat. Where the heating tool is stationary relative to the moving materials, this problem is not difficult to resolve. However, in the case in which the materials move across a stationary welding tool then various approaches can be adopted such as the use of a pressure pad or rollers over, before and/or after the welding tool as described in my co-pending British Application 4289/77 or with the use of an electrostatic force generated, tor example, in accordance with the apparatus described in my co-pending British Patent Application No. 52137/77.
It may be noted here that the apparatus and methods described in these specifications of earlier British applications of the present applicant represent initial work, further development of which resulted in the making of the present invention. In particular, it may be noted that in Figures 7 and 8 and the associated description of the complete specification of Application 4289/77 there is shown a construction in which the welding finger has a curved upper surface which provides a relatively large bearing surface in the direction of movement of the sheets. Hovever, as can be seen from a close examination of Figure 8 and from a study of the language used in connection therewith, the material being welded in fact is related only to a smaller area of this bearing surface during the actual welding operation and heat is applied only to this small area.In fact, the welding tool of this shape serves to avoid the situation in which the particular materials, net like materials, for example, snag on a welding finger which has only a small welding surface. With the construction shown in Figures 7 and 8, the weld can take place at different points across the bearing surface in accordance with the configuration of the materials.
In accordance with a further aspect of the present invention there is provided apparatus for securing plastics sheet materials by a heat welding process which comprises a welding finger or bar of heat conducting material which presents a welding surface on one end thereof which has a width to define the required weld width and a predetermined length and a heat reservoir block secured to the other end of the welding finger remote from the welding surface, the length of said other end of the welding finger being at least substantially equal to said predetermined length and the width of said other end of the welding finger being at least substantially equal to said weld width.
The heat reservoir block may be arranged so that it and the welding finger lie above the path of movement of the material being welded or it may lie below the said path. In either case, it is arranged so as to be removed as far as possible from the welding region and the remainder of the plastics material.
Preferably, heat shielding is provided between the reservoir block and the sheet materials passing thereacross. It is preferred to arrange the heat reservoir block vertically below the welding surface since heat is more readily transferred vertically upwardly. However, in certain circumstances, particularly where the welding tool is to move with the plastic sheet materials during the welding operation, it may be convenient to locate the heat reservoir block vertically above the welding surface or substantially vertically thereabove.
One embodiment of the apparatus of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic side view of the apparatus of the embodiment and Fig. 2 is a view on line Il-Il of Fig. 1.
The apparatus of this invention involves a framework which provides supports for two supply rolls of plastics sheet material and a takeup roll for the welded materials together with suitable rolls for establishing a path of movement for the plastics sheet materials across a work table. The general apparatus also includes motors for driving the takeup rolls and for various auxiliary rools as may be provided. This apparatus is described more specifically in the complete specification of co-pending application 4289/77 and need not be further described here.
In the schematic drawings of the apparatus of this invention there is shown the work table 1 across which sheet materials 2 and 3 are drawn after passing under a guide roller 4. A heat reservoir block 5 is located under the work table and is generally shielded form the work table by heat shielding 6 which may have the form of aluminium foil or plates. The heat reservoir block 5 incorporates an electrical resistance element which is not shown. Attached to the upper surface of the block 5 in heat conducting relationship thereto are a plurality of welding finger assemblies 7 which are spaced transversely across the upper surface of the heating block 5, tranversely that is with respect to the direction of movement of the sheet materials 2 and 3. Each assembly 7 incorporates a support plate 8 and a welding finger 9.The welding fingers are in the form of rectangular plates which have substantially uniform cross-section and provide first ends as welding surfaces which have a width such as to provide a predetermined weld width in the sheet materials 2 and 3 and a length in the direction of movement of the sheet materials 2 and 4 which will be determined as discussed hereinafter. The welding fingers 9 have other ends which have the same general surface configuration as the welding surface ends of the fingers 9 and are joined to the welding support plate 8.
Means are provided for keeping the sheet materials 2 and 3 in contact with the welding surfaces of the welding fingers 9 and, in the case of the present embodiment, such means incorporate a pad of resilient foam which is in contact with the upper surface of the sheets 2 and 3 and is located immediately above the welding fingers 9. Various alternative means may be employed in alternative embodiments of the apparatus. In particular, various such alternative means are shown in the description and drawings of co-pending Application 4289/77 and co-pending Application 5231 1/77.
In operation of the apparatus of the present invention described above with reference to the drawings, the supply reels and the takeup core are loaded in the apparatus and a leading edge of the sheets is drawn through the guide rollers and on to the takeup core. The drive motors are set in operation to draw the sheet materials across the welding fingers 9 in the path of movement of the sheet materials 2 and 3. The electrical resistance elements are heated to bring the tips of the welding fingers 9 to a required temperature which is slightly above the melting point of the materials being used, or the lowest melting point temperature where different materials are being welded together. The pressure pad 1 0 is then applied to the sheets to urge them into contact with the welding surfaces of the welding fingers and welds are effected.The speed at which the sheet materials 2 and 3 are drawn across the welding fingers will depend upon the length of the fingers 9 in the direction of travel of the sheet and of the thicknesses of the sheet materials involved. The various relationships have necessarily to be determined on a more or less empirical basis having regard, however, to the concepts of the invention discussed above. In principle, the longer the fingers 9 in the direction of movement of the material, then the higher the speed of feed of the material can be for a constant thickness material.Because of the constant cross-sectional configuration of the welding fingers between the heat block 5 and the welding surfaces themselves, one is able to assure a constant supply of heat over the whole length of the welding finger and, because of the substantial nature of the construction of the welding fingers, the continuity of heat supply is assured so that there is little, if any, risk of the development of cold spots on the welding finger surfaces and the subsequent and consequential failure of the material to be welded where they pass over these cold spots. The present invention can be embodied in various forms of apparatus and, for example, there is described in an application entitled "Plastics Sheet Material Welding Apparatus and Method" concurrently filed herewith, an application of the present invention to welding techniques in which a weld is applied transversely to the direction of movement of the sheet materials being welded, although the materials being welded move at a constant speed during the welding operation.

Claims (12)

  1. A method of securing superimposed layers of plastics sheet materials together which comprises pressing the sheet materials together and applying heat to at least one of the sheets at or about a temperature which is the flow or melting point temperature of one of the materials for a length of time sufficient to enable flow of the material at the point of application of heat to take place so as to effect securing of the sheet materials together.
  2. 2. A method according to claim 1 wherein the heat is applied only by direct contact and only at said point of application, the remainder of the sheet materials being shielded from the heat and held at a temperature substantially below said temperature.
  3. 3. A method according to claim 1 or claim 2 wherein the sheet materials have different melting or flow point temperatures and the heat is applied at or about the lower one thereof.
  4. 4. A method according to any one of the preceding claims wherein one of said sheet materials is continuous and the other has a mesh-like form and the heat is applied to the continuous sheet material on the side thereof remote from the mesh-like material.
  5. 5. A method according to any preceding claim wherein the sheets are moved continuously past a heat source.
  6. 6. A method according to claim 5 wherein the sheets are moved together over a heated welding tool having a length in the direction of sheet travel such as to permit successful said securing at a relatively high rate of sheet travel.
  7. 7. A method according to claim 6 wherein the tool is mounted on a heat bank and is of a substantially rectangular configuration so as to provide substantially parallel heat paths between the heat bank and the surface of the tool over which the sheet materials pass.
  8. 8. Apparatus for securing plastics sheet materials by a heat welding process which comprises a welding finger or bar of heat conducting material which presents a welding surface on one end thereof which has a width to define the required weld width and a predetermined length and a heat reservoir block secured to the other end of the welding finger remote from the welding surface, the length of said other end of the welding finger being at least substantially equal to said predetermined length and the width of said other end of the welding finger being at least substantially equal to said weld width.
  9. 9. Apparatus according to claim 8 in which the heat reservoir block is arranged so that it and the welding finger lie below the path of movementof the material being welded.
  10. 10. Apparatus according to claim 9 wherein heat shielding is provided between the reservoir block and the sheet materials passing over said surface.
  11. 1 1. A method of securing superimposed layers of plastics material together substantially as hereinbefore described with reference to the accompanying drawings.
  12. 12. Apparatus for securing superimposed layers of plastics material together substantially as hereinbefore described with reference to the accompying drawings.
GB7830506A 1978-07-20 1978-07-20 Welding of plastics materials Withdrawn GB2027390A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4496616A (en) * 1981-03-23 1985-01-29 Raychem Limited Strip of heat-recoverable articles
EP0278927A2 (en) * 1987-02-13 1988-08-17 A.W.A.X. PROGETTAZIONE E RICERCA S.r.l. Device for continuous hot-sealing of thermoplastic films

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4496616A (en) * 1981-03-23 1985-01-29 Raychem Limited Strip of heat-recoverable articles
EP0278927A2 (en) * 1987-02-13 1988-08-17 A.W.A.X. PROGETTAZIONE E RICERCA S.r.l. Device for continuous hot-sealing of thermoplastic films
EP0278927A3 (en) * 1987-02-13 1990-07-25 A.W.A.X. PROGETTAZIONE E RICERCA S.r.l. Device for continuous hot-sealing of thermoplastic films

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