Fiber-reinforced epoxy composite joints

• US 3,885,071 A
• Filed: 08/10/1972
• Issued: 05/20/1975
• Est. Priority Date: 08/10/1972
• Status: Expired due to Term

• Current Assignee: Leiv H. Blad, Robert F. Warkow
• Original Assignee: Leiv H. Blad, Robert F. Warkow
• Inventors: Blad, Leiv H., Warkow, Robert F.
• Primary Examiner(s): Lesmes, George F.
• Assistant Examiner(s): Lipsey, Charles E.
• Application Number:
  US05/279,703
• Time in Patent Office: 1,013 Days
• Field of Search: 161/36,37,38,53,143,144,145,184,185,60 156/2,3,157,158,159,304,306 74/232
• US Class Current: 428/60
• CPC Class Codes: B29C 37/0082 Mechanical anchoring B29C66/303 takes precedence
• CPC Class Codes: B29C 65/4815 Hot melt adhesives, e.g. thermoplastic adhesives
• CPC Class Codes: B29C 65/4835 Heat curing adhesives
• CPC Class Codes: B29C 65/5057 positioned between the surfaces to be joined B29C65/5035 takes precedence
• CPC Class Codes: B29C 65/8215 Tensile tests
• CPC Class Codes: B29C 66/00145 Vacuum, e.g. partial vacuum
• CPC Class Codes: B29C 66/0222 without removal of material, e.g. cleaning by air blowing or using brushes
• CPC Class Codes: B29C 66/02245 Abrading, e.g. grinding, sanding, sandblasting or scraping
• CPC Class Codes: B29C 66/026 Chemical pre-treatments B29C66/028 takes precedence
• CPC Class Codes: B29C 66/1142 Single butt to butt joints
• CPC Class Codes: B29C 66/1162 Single bevel to bevel joints, e.g. mitre joints
• CPC Class Codes: B29C 66/14 the joint having the same thickness as the thickness of the parts to be joined B29C66/1142 takes precedence
• CPC Class Codes: B29C 66/30321 making use of protrusions belonging to at least one of the parts to be joined
• CPC Class Codes: B29C 66/43 Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/7212 characterised by the composition of the fibres
• CPC Class Codes: B29C 66/72141 Fibres of continuous length
• CPC Class Codes: B29C 66/73941 characterised by the materials of both parts being thermosets
• CPC Class Codes: B29C 66/742 to metals or their alloys
• CPC Class Codes: B29C 66/9141 by controlling or regulating the temperature
• CPC Class Codes: B29C 66/919 : characterised by specific temperature, heat or thermal flux values or ranges specific electrical resistance values B29C66/81262
• CPC Class Codes: B29C 66/929 : characterized by specific pressure, force, mechanical power or displacement values or ranges
• CPC Class Codes: B29C 66/949 : characterised by specific time values or ranges
• CPC Class Codes: B29K 2063/00 : Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/101 : Oriented
• CPC Class Codes: B29K 2277/00 : Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as reinforcement
• CPC Class Codes: B29K 2307/00 : Use of elements other than metals as reinforcement
• CPC Class Codes: B29K 2307/02 : Boron
• CPC Class Codes: B29K 2307/04 : Carbon
• CPC Class Codes: B29K 2309/08 : Glass
• CPC Class Codes: B32B 27/08 : of synthetic resin
• CPC Class Codes: B32B 27/12 : next to a fibrous or filamentary layer
• CPC Class Codes: B32B 27/38 : comprising epoxy resins
• CPC Class Codes: H05K 1/0366 : reinforced, e.g. by fibres, fabrics H05K1/036 takes precedence
• CPC Class Codes: H05K 1/142 : Arrangements of planar printed circuit boards in the same plane, e.g. auxiliary printed circuit insert mounted in a main printed circuit
• CPC Class Codes: H05K 3/0017 : Etching of the substrate by chemical or physical means
• CPC Class Codes: H05K 3/36 : Assembling printed circuits with other printed circuits H05K7/142 takes precedence
• CPC Class Codes: Y10S 273/03 : Epoxy
• CPC Class Codes: Y10S 273/23 : High modulus filaments
• CPC Class Codes: Y10T 428/195 : Beveled, stepped, or skived in thickness
• CPC Class Codes: Y10T 428/249945 : Carbon or carbonaceous fiber
• CPC Class Codes: Y10T 428/249946 : Glass fiber

Abstract

An improved manufacture including a fiber-reinforced epoxy composite joint, and the method of producing same, in which the fibers of each of the composite adherends pass through and are intermeshed across the joint bondline. A scarfed mating surface is prepared on the end of each of the adherend elements-to-bejoined, after which a chemical etching of the mating ends to obtain exposed lengths of filaments or fibers is provided. A sheet of unsupported adhesive material is inserted between the scarfed and etched mating surfaces prior to their layup, after which heat and pressure are applied for bonding the joint. The exposed fibers of each element cross the bondline to intermesh with those of the other element during the melting of the unsupported adhesive. This process increases the joint efficiency to 83 percent of the efficiency of a non-joined element.

Claims

1. AN IMPROVED FIBER-REINFORCED EPOXY COMPOSITE JOINT COMPRISING AT LEAST A PAIR OF FIBER-REINFORCED EPOXY COMPOSITE ADHERENDS HAVING ENDS SCARFED AND MATED IN COMPLEMENTARY RELATION TO EACH OTHER ACROSS AN UNSUPPORTED ADHESIVE, ALL BLONDED TOGETHER, EACH OS SUCH ADHERENDS HAING A PLURAITY OF LAYERS OF SUBSTANTIALLY EQUALLY EXPOSED LENGTHS OF INERT FIBERS DISPOSED WITHIN AND EXTENDING UNIDIRECTIONALLY FROM ITS SCARFED MATING SURFACE SUBSTANTIALLY PARALLED TO THE LONGITUDINAL AXIS OF THE ELEMENTS-TO-BE-JOINED AND BEING INTERMESHED WITH LIKE LENGTHS OF FIBERS EXTENDING FROM THE OTHER ADHEREND.

2. The improved fiber-reinforced epoxy composite joint of claim 1 wherein said inert fibers are selected from the class of materials comprising graphite, boron, glass pitch blend, carbon, and high modulous organic fiber compositions.

3. The improved fiber-reinforced epoxy composite joint of claim 1 wherein said ends are scarfed at angles of from 4* and 6*.