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
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
  • B29C44/12—Incorporating or moulding on preformed parts, e.g. inserts or reinforcements
• • 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
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/34—Auxiliary operations
  • B29C44/36—Feeding the material to be shaped
  • B29C44/38—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length
  • B29C44/42—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length using pressure difference, e.g. by injection or by vacuum
• • 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
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/68—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks
  • B29C70/74—Moulding material on a relatively small portion of the preformed part, e.g. outsert moulding
• • 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
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/68—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks
  • B29C70/74—Moulding material on a relatively small portion of the preformed part, e.g. outsert moulding
  • B29C70/76—Moulding on edges or extremities of the preformed part
  • B29C70/763—Moulding on edges or extremities of the preformed part the edges being disposed in a substantial flat plane
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
  • B60R13/06—Sealing strips
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D23/00—General constructional features
  • F25D23/08—Parts formed wholly or mainly of plastics materials
  • F25D23/082—Strips
  • F25D23/087—Sealing strips
• • 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
  • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
  • B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
  • B29C67/246—Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM]
• • 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
  • B29K2075/00—Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• • 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
  • B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
• • 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
  • B29L2031/26—Sealing devices, e.g. packaging for pistons or pipe joints
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2400/00—General features of, or devices for refrigerators, cold rooms, ice-boxes, or for cooling or freezing apparatus not covered by any other subclass
  • F25D2400/10—Refrigerator top-coolers

Definitions

• This invention relates to a sealing gasket.
• the operational requirements for the door sealing gasket of a modern refrigerator or freezer door are very demanding.
• the gasket must provide an effective sealing perimeter, must be sufficiently durable and resilient to form a seal repetitively over years of use, and should be able to withstand repeated pinching or rolling action adjacent to the hinge axis.
• the gasket is mounted in such a way as also to prevent ingress of moisture to insulation situated between an inner and outer door panel and provides for hidden mounting to the door.
• gaskets which extend longitudinally of the perimeter of the door and typically include a flat sealing surface, an air chamber or bellow structure providing a degree of resilience, means adapted to receive magnets, and one or more mounting flanges or flaps to aid unseen mounting of the gasket to the door.
• the gasket fits over an edge of the inner panel of the door so as to provide an edge seal between the panel and a panel mounting flange of the door.
• Such gaskets have a relatively complex cross-section. They are generally manufactured from polyvinyl chloride (“PVC”) by extruding continuous lengths, cutting required lengths, with mitre, cut ends forming a door perimeter gasket by welding four of the cut lengths end to end to form a substantially rectangular perimeter and the rectangular shape gasket so manufactured is then mounted to the refrigerator or freezer door usually by stretching over the edge of a door panel and/or by means of a mounting strip screwed at inch intervals around the perimeter.
• PVC polyvinyl chloride
• Gaskets such as described above are in wide-spread use in freezers and refrigerators throughout Australia and elsewhere in the world. However they are costly to manufacture, costly to mount to the door, and are not as satisfactory in performance as is desired.
• the present invention has as an object to alleviate at least some of the above mentioned disadvantages. Disclosure of Invention
• the invention consists in a method for manufacture of a gasket adapted to provide a seal between one article and another, said method being characterised by the step of forming a suitable microcellular polyurethane in a predetermined gasket shape in situ on the article.
• the polyurethane is a low density microcellular polyurethane and is formed by reaction injection moulding ("RIM") in the required shape in situ on the article.
• RIM reaction injection moulding
• the gasket is integral with the article by virtue of chemical bonding or mechanical interlocking therewith and may extend around a rim of the article being in contact with opposite faces adjacent the rim.
• the invention consists in an article having a suitable microcellular polyurethane portion formed as an integral part thereof, said part being adapted to provide a sealing gasket between the article and a surface.
• the article is a door panel of a freezer refrigerator or other appliance, the panel being a high density polyurethane moulding having a low density polyurethane gasket moulded integrally therewith.
• the panel need not be of high density polyurethane and may be of metal, thermoplastic or other material.
• Fig. 1 is an isometric drawings of a freezer lid assembly according to the invention, partly shown in scrap cross-section.
• Fig. 2 shows in more detail a cross-section through an edge portion of the lid of Fig. 1.
• Fig. 3 shows schematically a second embodiment of the invention.
• Fig. 4 shows schematically a third embodiment of the invention.
• FIG. 1 and 2 shows the insulated door or lid assembly of a top opening domestic freezer cabinet.
• the lid assembly comprises an outer panel 1, an inner panel or liner 2, and a connecting frame 3.
• the ' connecting frame 3 provides the front edge 4, rear edge 5, and side edges 6,7 for the lid, and is adapted to hold the outer panel 1 and inner panel 2 in spaced apart arrangement.
• More particularly _ connecting frame 3 comprises a moulding which in the assembled lid extends around the perimeter of the lid assembly.
• the moulding of connecting frame 3 comprises an upper flange 21, an
• OMPI outer side 22 a downwardly extending skirt 23, a lower seal engaging formation 25, and a groove 24 extending parallel to the perimeter and defined between skirt 23 and formation 25.
• Upper flange 21 extends inwardly from inner side surface 26 and serves to frame and retain outer panel 1.
• Outer side edge 22 slopes outwardly and downwardly then steps outwardly to merge with skirt 23.
• the inner panel or liner 2 is stepped in profile near the edge and has a flat edge rim 27.
• a gasket 30 extends around the perimeter of rim 27 of panel 2, a portion 31 of rim 27 being embedded in gasket 30.
• Gasket 30 fulfils the dual role of providing a seal between inner liner 2 and formation 25 of frame 3, and also of acting as a door seal gasket for sealing with the door frame or lip of a freezer cabinet (indicated schematically at 32).
• Frame 3 is provided with a handle formation and hinge formations or mounting means which are not shown in the drawings.
• Gasket 30 is endless and is made of microcellular polyurethane foam moulded in situ about the perimeter of inner liner 2. It does not have a mitered joint and it is not required to be stretchable in order for it to be fitted around the perimeter of panel 2.
• the connecting frame and the inner and outer panel is each manufactured from high density polyurethane by means of reaction injection moulding.
• a composition containing a di-isocyanate, a polyester and/or polyether polyol with a catalyst is injected into a split mould as a liquid and subsequently reacts to form a solid polyurethane in the desired shape.
• inner panel 2 After inner panel 2 has been formed, removed from the mould, and prior to its assembly with the other parts of the door, inner panel 2 is placed in another split mould which is assembled so as to enclose rim 27 of panel 2 and a low density microcellular polyurethane is formed by reaction injection moulding within the mould. There is thus formed gasket 30 which extends around the perimeter of the panel as shown in Figure 2.
• inner panel 2 is provided with key formation 33 which provides additional mechanical interlocking with the moulded .
• gasket 30 formed in situ. While it is preferable that the polyurethane gasket adheres to and is unified with the panel on which it is moulded, the invention embraces constructions in which the gasket is integral with the
• gasket 30 formed in situ need not be unified with the panel.
• the panel may be provided with a release coating prior to formation of the gasket.
• the gasket may be retained by mechanical formations or may be adhesively bonded to the article or may be integrally formed with the article.
• the gasket need not extend around the perimeter of a panel and in other embodiments of the invention the gasket may be of a rectangular or other cross-section and may be formed on a surface of an article.
• the gasket portion is formed as a low density polyurethane microcellular foam in which for preference the body of the gasket is an open cell foam structure and is formed with a integral outer skin or membrane.
• Fig. 4 shows schematically in cross section portion of an article 40 moulded from high density polyurethane and having a gasket 30 moulded from low density microcellular foam unified therewith by RIM moulding on the surface of article 40.
• Gasket 30 is formed with an integral outer skin 41.
• compositions suitable for use in RIM machinery to produce high density polyurethane mouldings or thermoplastic mouldings such as may be used for the panel are well known in the art.
• Compositions suitable for use to produce low density microcellular polyurethanes are also well known in the polyurethane art although believed not previously to have been caused to react in high pressure RIM machinery to give satisfactory gasket properties.
• compositions to produce polyurethanes will readily understand that properties such as the resilience, hardness, compressibility, tear strength, stiffness and the like of the finished gasket can be adjusted by variation in the composition injected into the mould and by control of the moulding conditions although some experiment may be necessary to produce a gasket having a particularly desired set of properties.
• a satisfactory gasket was produced using a formulation based on Isocyanate 240 obtained from Upjohn Chemicals and Voranol 5148 from Dow Chemicals together with conventional extenders, catalysts, pigments, blowing agents, surfactants, flame retardant and water.
• Components 1 & 2 are diphenylmethane diisocyanate obtained from Upjohn Chemicals.
• Components 3 and 4 are Veranol (molecular wt 5148) and Veranol (molecular wt 4701) obtained from Dow Chemicals.
• Component 5 is ethylene glycol.
• Component 6 is methyl diethanolamine.
• Component 8 is a silicone obtained from Dow Corning.
• Component 9 is a dimethyl cyclohexamine.
• Components 10 and 11 are dibutyl tin dilaurate.
• Component 12 is a trichlorotrifluro- ⁇ -ethyl-phosphate.
• Component 13 is methylene chloride.
• Component 14 is triethylene diammine 33% in dipropylene gly ⁇ ol.
• Component 15 is triethanolamine.
• magnetic material may be incorporated in gaskets formed according to the invention. Whether a gasket bonds chemically or mechanically will be influenced by the nature of the substrate and by use, if desired, of release coatings. Freezer doors according to the invention could readily be provided with a plurality of gaskets for example an inner gasket and an outer gasket, which has hitherto been impracticable because of fixing requirements. Thus the heat losses through the seals could be reduced.
• the invention has application in providing door frames and window frames having integral seals, for use both in construction and in other industries such as the automobile industry and is generally useful for providing parts with an integral gasket for appliances, machinery, and for many other purposes.
• Those sTilled in the art will readily appreciate from the teaching hereof how the concept may be applied to other embodiments and such embodiments are incorporated within the scope hereof.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Refrigerator Housings (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=3770046

Family Applications (1)

Country Status (3)

Cited By (9)

Families Citing this family (1)

Citations (3)

• 1984
  • 1984-03-16 EP EP84901178A patent/EP0151119A1/en not_active Withdrawn
  • 1984-03-16 WO PCT/AU1984/000045 patent/WO1984003659A1/en not_active Application Discontinuation
  • 1984-03-16 JP JP50121984A patent/JPS60501620A/ja active Pending

Patent Citations (3)

Non-Patent Citations (1)

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