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WO1999054115A1 - Method for joining plastic members together - Google Patents

Method for joining plastic members together Download PDF

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Publication number
WO1999054115A1
WO1999054115A1 PCT/ZA1999/000022 ZA9900022W WO9954115A1 WO 1999054115 A1 WO1999054115 A1 WO 1999054115A1 ZA 9900022 W ZA9900022 W ZA 9900022W WO 9954115 A1 WO9954115 A1 WO 9954115A1
Authority
WO
WIPO (PCT)
Prior art keywords
packing member
plastic members
filler material
base material
packing
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.)
Ceased
Application number
PCT/ZA1999/000022
Other languages
French (fr)
Inventor
Nicolaas Daniel Lombard Burger
Rudolf Werner Ottermann
Petrus Johannes Adriaan Van Zyl
Adam Jacobus Von Wielligh
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to AU36744/99A priority Critical patent/AU3674499A/en
Publication of WO1999054115A1 publication Critical patent/WO1999054115A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • 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
    • 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
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/1403—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the type of electromagnetic or particle radiation
    • B29C65/1425—Microwave 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
    • B29C66/114—Single butt joints
    • B29C66/1142—Single butt to butt 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
    • B29C66/50—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
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5221—Joining tubular articles for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
    • 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
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/1477—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation making use of an absorber or impact modifier
    • 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
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • B29C65/4805—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding characterised by the type of adhesives
    • B29C65/481—Non-reactive adhesives, e.g. physically hardening adhesives
    • B29C65/4815—Hot melt adhesives, e.g. thermoplastic adhesives
    • 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
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • B29C65/50—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding using adhesive tape, e.g. thermoplastic tape; using threads or the like
    • B29C65/5057—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding using adhesive tape, e.g. thermoplastic tape; using threads or the like positioned between the surfaces 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
    • B29C66/70—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
    • B29C66/739—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 material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/7392—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 material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
    • B29C66/73921—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 material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
    • 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
    • B29C66/87—Auxiliary operations or devices
    • B29C66/874—Safety measures or devices
    • B29C66/8742—Safety measures or devices for operators

Definitions

  • This invention relates to a method of joining plastic members together and to a packing member for aiding the joining of plastic members together.
  • plastic members such as plastic pipes have been welded together by heating the ends to a predetermined temperature and thereafter pressing said heated ends together and holding same in position until they are cooled and welded together. Heating of the ends was typically effected by means of a heated plate which conformed to the ends of the pipes.
  • One of the disadvantages associated with this particular method is that it takes approximately 1 hour to raise the temperature of the ends to the desired temperature since heating has to be effected fairly slowly in order not to disturb the material properties.
  • a further disadvantage of this method is that burrs could be formed on the weld joints, which in turn could disrupt the flow pattern of a liquid flowing through the plastic pipe.
  • a method of joining plastic members together which includes the steps of:- directing energy in the form of electromagnetic waves having a frequency within the range of 1MHz to 40GHz towards zones of the plastic members to be joined, thereby to raise the temperature of the zones to a desired temperature; and urging the zones into abutment with each other and maintaining same in this position until at least portions of the zones are joined.
  • the method may include arranging a packing member having sides which conform to the zones to be joined between the zones prior to the step of directing the electromagnetic waves, the packing member being formed from a material consisting of a base material of substantially the same material as the plastic members and a filler material which has a higher loss tangent value (tan ⁇ ) than the base material so as to facilitate heating
  • the plastic members may be formed from any suitable weldable thermoplastic material and which may include any suitable weldable thermoplastic material selectable from the group including Polyethylene (PE) , Acrylo Butadiene Styrene (ABS) and Polypropylene (PP) .
  • PE Polyethylene
  • ABS Acrylo Butadiene Styrene
  • PP Polypropylene
  • the filler material may include any suitable material having a higher loss tangent value (tan ⁇ ) relative to the base material and of the plastic members to be joined together.
  • the filler material may be polar i.e. have an uneven distribution of charge within its molecular structure.
  • the desired temperature preferably is in the region of the melting temperature of the base material.
  • the filler material may include polyaniline or conductive carbon black. Furthermore, the polyaniline filler material may comprise between 20 - 60% by weight of the packing material, typically 60%. The conductive carbon black filler material may comprise between 1% - 20% by weight of the packing material, and most preferably 3%.
  • the electromagnetic waves may be generated by any suitable microwave generative device such as a magnetron, silicon transistor and/or klystron.
  • the frequency of the electromagnetic waves is preferably 2.45 GHz.
  • a packing member as described above for aiding the joining or welding of plastic members together.
  • Figure 1 shows a cross-sectional view of pipes to be joined in accordance with the method of the invention
  • Figure 2 shows a cross-sectional view of a further example of a method of joining pipes in accordance with the invention.
  • Figure 3 shows an enlarged view of a part of Figure 2.
  • reference numeral 10 generally designates weldable thermoplastic pipes to be joined and reference numeral 12 a packing member in the form of a gasket for facilitating welding of the pipes 10.
  • the gasket 12 is comprised of a base material corresponding to that of the pipes 10 and which may include any of the group including PE, PP and ABS and further material selected from this group including polyaniline and conductive carbon black.
  • the filler material has a higher loss tangent value (tan ⁇ ) relative to the base material.
  • the thickness of the gasket may vary between 0.5mm and 20mm.
  • Figure 2 shows a sleeve 14 which is arranged co- axially around the pipes 10 to be welded along an outer surface thereof towards its ends, and which would typically be employed when a rupture or hole is made in a pipe and where it is impractical for the pipes to be pulled closer together given the lengths thereof.
  • the sleeve 14 has outer and inner portions 16.1 and 16.2 comprised of base material and an intermediate portion 18 of packing material comprising filler material and base material as described above.
  • electromagnetic waves are directed towards the members 12, 14 and the plastic pipes 10 thereby to heat the packing member 12 and portion 18 of sleeve 14 to the melting point of the base material.
  • the gasket 12 and/or sleeve 14 are then urged into abutment with the surfaces of the ends 20 or outer portion 22 of the pipes 10 and maintained in this position until the packing member has cooled sufficiently thereby to provide a weld or join between the ends 20 of the pipes 10 and the outer portion 22 of the pipes 10 respectively.
  • the electromagnetic waves may be generated by any suitable microwave generating device such as a magnetron, silicon transistor and/or klystron and which preferably generate waves having a frequency conventionally of 2.45 GHz.
  • the microwave generating device will typically be arranged internally the pipe, the waves thus radiating outwards towards the packing member.
  • a shield may be arranged over the zone of the sleeve and/or gasket so as to prevent harm or injury caused by the radiation waves to a user.
  • the packing material to be heated to the melting point of the base material in a much reduced time when compared to the 1 hour required conventionally when using the heated plate method described above and which typically is in the region of between 1 and 5 minutes. Accordingly, by reducing the time required to effect the welding or joining of the pipes, the applicants believe that the invention will provide a cost-effective, economic and simple solution for welding pipes in in si tu when compared to the conventional techniques currently employed.
  • the invention is not limited to the precise constructional details as hereinbefore described, for example the configuration and/or shape of the packing member/sleeve may be varied as desired according to the shape of the members to be welded or joined together.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Branch Pipes, Bends, And The Like (AREA)

Abstract

A method for joining plastic members (10) together, which includes heating those portions (20) of the members which will be joined by directing electromagnetic waves at said portions (20). The method may include inserting a packing member (12) conforming to the portions (20) to be joined between the two plastic members to be joined. The packing member (12) typically comprises a base material which is essentially identical to that of the plastic members (10) and a filler material (not shown) which has a higher loss tangent (tanδ) relative to the base material.

Description

METHOD FOR JOINING PLASTIC MEMBERS TOGETHER
This invention relates to a method of joining plastic members together and to a packing member for aiding the joining of plastic members together.
In the past, plastic members such as plastic pipes have been welded together by heating the ends to a predetermined temperature and thereafter pressing said heated ends together and holding same in position until they are cooled and welded together. Heating of the ends was typically effected by means of a heated plate which conformed to the ends of the pipes. One of the disadvantages associated with this particular method is that it takes approximately 1 hour to raise the temperature of the ends to the desired temperature since heating has to be effected fairly slowly in order not to disturb the material properties. A further disadvantage of this method is that burrs could be formed on the weld joints, which in turn could disrupt the flow pattern of a liquid flowing through the plastic pipe.
According to an aspect of the invention there is provided a method of joining plastic members together which includes the steps of:- directing energy in the form of electromagnetic waves having a frequency within the range of 1MHz to 40GHz towards zones of the plastic members to be joined, thereby to raise the temperature of the zones to a desired temperature; and urging the zones into abutment with each other and maintaining same in this position until at least portions of the zones are joined.
The method may include arranging a packing member having sides which conform to the zones to be joined between the zones prior to the step of directing the electromagnetic waves, the packing member being formed from a material consisting of a base material of substantially the same material as the plastic members and a filler material which has a higher loss tangent value (tanδ) than the base material so as to facilitate heating
of the base material. Put another way, tanδ base material < tanδ filler "-ateriai • For the purpose of this application, the term "loss tangent" (tanδ) is defined as:-
tanδ = (loss constant of a material) / ( dielectric constant
of a material ) = (ε**) / (ε s)
Further explanation of tanδ is set out in annexure "A" .
The plastic members may be formed from any suitable weldable thermoplastic material and which may include any suitable weldable thermoplastic material selectable from the group including Polyethylene (PE) , Acrylo Butadiene Styrene (ABS) and Polypropylene (PP) .
The filler material may include any suitable material having a higher loss tangent value (tanδ) relative to the base material and of the plastic members to be joined together. The filler material may be polar i.e. have an uneven distribution of charge within its molecular structure.
The desired temperature preferably is in the region of the melting temperature of the base material.
The filler material may include polyaniline or conductive carbon black. Furthermore, the polyaniline filler material may comprise between 20 - 60% by weight of the packing material, typically 60%. The conductive carbon black filler material may comprise between 1% - 20% by weight of the packing material, and most preferably 3%.
The electromagnetic waves may be generated by any suitable microwave generative device such as a magnetron, silicon transistor and/or klystron. The frequency of the electromagnetic waves is preferably 2.45 GHz. According to another aspect of the invention there is provided a packing member as described above for aiding the joining or welding of plastic members together.
The invention will now be described by way of example with reference to the accompanying drawings.
In the drawings :-
Figure 1 shows a cross-sectional view of pipes to be joined in accordance with the method of the invention;
Figure 2 shows a cross-sectional view of a further example of a method of joining pipes in accordance with the invention; and
Figure 3 shows an enlarged view of a part of Figure 2.
Referring now to Figure 1, reference numeral 10 generally designates weldable thermoplastic pipes to be joined and reference numeral 12 a packing member in the form of a gasket for facilitating welding of the pipes 10.
The gasket 12 is comprised of a base material corresponding to that of the pipes 10 and which may include any of the group including PE, PP and ABS and further material selected from this group including polyaniline and conductive carbon black. In particular, the filler material has a higher loss tangent value (tanδ) relative to the base material. The thickness of the gasket may vary between 0.5mm and 20mm. Figure 2 shows a sleeve 14 which is arranged co- axially around the pipes 10 to be welded along an outer surface thereof towards its ends, and which would typically be employed when a rupture or hole is made in a pipe and where it is impractical for the pipes to be pulled closer together given the lengths thereof.
As shown in Figure 3, the sleeve 14 has outer and inner portions 16.1 and 16.2 comprised of base material and an intermediate portion 18 of packing material comprising filler material and base material as described above.
In operation, electromagnetic waves are directed towards the members 12, 14 and the plastic pipes 10 thereby to heat the packing member 12 and portion 18 of sleeve 14 to the melting point of the base material. The gasket 12 and/or sleeve 14 are then urged into abutment with the surfaces of the ends 20 or outer portion 22 of the pipes 10 and maintained in this position until the packing member has cooled sufficiently thereby to provide a weld or join between the ends 20 of the pipes 10 and the outer portion 22 of the pipes 10 respectively. The electromagnetic waves may be generated by any suitable microwave generating device such as a magnetron, silicon transistor and/or klystron and which preferably generate waves having a frequency conventionally of 2.45 GHz. The microwave generating device will typically be arranged internally the pipe, the waves thus radiating outwards towards the packing member. A shield may be arranged over the zone of the sleeve and/or gasket so as to prevent harm or injury caused by the radiation waves to a user.
The applicants believe that the method and packing member in accordance with the invention is advantageous in that the higher loss tangent value (tanδ) of the filler material permits
the packing material to be heated to the melting point of the base material in a much reduced time when compared to the 1 hour required conventionally when using the heated plate method described above and which typically is in the region of between 1 and 5 minutes. Accordingly, by reducing the time required to effect the welding or joining of the pipes, the applicants believe that the invention will provide a cost-effective, economic and simple solution for welding pipes in in si tu when compared to the conventional techniques currently employed.
The invention is not limited to the precise constructional details as hereinbefore described, for example the configuration and/or shape of the packing member/sleeve may be varied as desired according to the shape of the members to be welded or joined together.

Claims

1. A method of joining plastic members together which includes the steps of:-
directing energy in the form of electromagnetic waves having a frequency within the range of 1MHz to 40GHz towards zones of the plastic members to be joined, thereby to raise the temperature of the zones to a desired temperature; and
urging the zones into abutment with each other and maintaining same in this position until at lea.-^t portions of the zones are joined.
2. A method as claimed in claim 1 which includes arranging a packing member having sides which conform to the zones to be joined between the zones prior to the step of directing the electromagnetic waves, the packing member being formed from a material consisting of a base material of substantially the same material as the plastic members and a filler material which has a higher loss tangent value (tanδ) than the base material so as to facilitate heating of the base material.
3. A method as claimed in claim 1 or 2 wherein the plastic members are formed from any suitable weldable thermoplastic material.
4. A method as claimed in claim 3 wherein the weldable thermoplastic material is selectable from the group including Polyethylene (PE) , Polypropylene (PP) and Acrylo Butadiene Styrene (ABS) .
5. A method as claimed in any one of claims 2 to 4 wherein the filler material is polar.
6.
A method as claimed in any of the preceding claims wherein the desired temperature is in the region of the melting temperature of the base material.
7. A method as claimed in any of claims 2 to 6 wherein the filler material includes polyaniline or carbon black, preferably conductive carbon black.
8. A method as claimed in claim 7 wherein the polyaniline filler material comprises between 20 - 60% by weight of the packing material, typically 60%.
9. A method as claimed in claim 8 wherein the carbon black filler material comprises between 1% - 20% by weight of the packing material, and most preferably 3%.
10. A method as claimed in any of the preceding claims wherein the electromagnetic waves are generated by any suitable microwave generative device such as a magnetron, silicon transistor and/or klystron.
11. A method as claimed in any of the preceding claims wherein the frequency of the electromagnetic waves is 2.45 GHz.
12. A packing member for aiding the joining of plastic members together including:
a base material of substantially the same material as the plastic members to be joined; and
a filler material which has a higher loss tangent value (tanδ) than the base material.
13. A packing member as claimed in claim 11 wherein the base material is a weldable thermoplastic material selectable from the group including Polyethylene (PE) , Acrylo Butadiene Styrene (ABS) and Polypropylene (PP) .
14. A packing member as claimed in claim 12 or 13 wherein the filler material is polar.
15. A packing member as claimed in claim 14 wherein the filler material includes polyaniline or carbon black, preferably conductive carbon black.
16. A packing member as claimed in claim 15 wherein the polyaniline filler material comprises between 20 - 60% by weight of the packing material, typically 60%.
17. A packing member as claimed in claim 15 wherein the carbon black filler material comprises between 1% - 20% by weight of the packing material, and most preferably 3%.
10
PCT/ZA1999/000022 1998-04-22 1999-04-22 Method for joining plastic members together Ceased WO1999054115A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU36744/99A AU3674499A (en) 1998-04-22 1999-04-22 Method for joining plastic members together

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA98/3364 1998-04-22
ZA983364 1998-04-22

Publications (1)

Publication Number Publication Date
WO1999054115A1 true WO1999054115A1 (en) 1999-10-28

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PCT/ZA1999/000022 Ceased WO1999054115A1 (en) 1998-04-22 1999-04-22 Method for joining plastic members together

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WO (1) WO1999054115A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2240980A (en) * 1990-01-24 1991-08-21 Univ Virgina Alumni Patents Fo Process of forming joints in vulcanised rubber articles
WO1993010962A1 (en) * 1991-11-27 1993-06-10 Minnesota Mining And Manufacturing Company Method and article for microwave bonding of polyethylene pipe
JPH0873753A (en) * 1994-07-01 1996-03-19 Sekisui Chem Co Ltd Resin composition for fusion with microwave and joint fused with microwave
JPH08336898A (en) * 1995-06-14 1996-12-24 Sekisui Chem Co Ltd Method for connecting thermoplastic resin tube
JPH0967461A (en) * 1995-09-01 1997-03-11 Sekisui Chem Co Ltd Resin composition for fusing with microwave

Patent Citations (5)

* Cited by examiner, † Cited by third party
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GB2240980A (en) * 1990-01-24 1991-08-21 Univ Virgina Alumni Patents Fo Process of forming joints in vulcanised rubber articles
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