Structural panel and method of making same

Claim 1

A method of making a structural panel comprised of fiberreinforced skin sheets having a thermosetting foamable resin composition core therebetween for use in building structures and the like, comprising the steps of applying a first layer of gel coat to spaced surfaces of a mold which are configured to provide a panellike structure applying a first layer of polyester resin onto said gel coat, applying a first layer of glass fiber rovinG onto said layer of polyester resin before curing thereof, forcing the glass fiber roving into said first layer of resin in a manner to impregnate the roving fibers into said first layer of resin, applying a second layer of polyester resin into the combined first layer of resin and fibers, applying a second layer of glass fibers onto said second layer of resin before said second layer of resin is cured such that portions of the fibers of said second layer of fibers project outwardly from said second layer of resin on said space surfaces, curing said layers of resin, and introducing a thermosetting foamable core composition into a cavity defined by said spaced surfaces such that the thermosetting core composition substantially fills said cavity and integrally adheres to said opposing spaced surfaces and outwardly projecting fibers thereon to provide an increased area of surface adhesion between the thermosetting core composition and each of said skin sheet fibers, and effecting curing of said thermosetting core composition.

Claim 2

A method of making a structural panel comprised of fiberreinforced skin sheets having a thermosetting foamable resin composition core therebetween for use in building structures and the like, comprising the steps of applying a first layer of gel coat to spaced surfaces of a mold which are configured to provide a panellike structure applying a first layer of polyester resin onto said gel coat, applying a first layer of glass fiber rovinG onto said layer of polyester resin before curing thereof, forcing the glass fiber roving into said first layer of resin in a manner to impregnate the roving fibers into said first layer of resin, applying a second layer of polyester resin into the combined first layer of resin and fibers, applying a second layer of glass fibers onto said second layer of resin before said second layer of resin is cured such that portions of the fibers of said second layer of fibers project outwardly from said second layer of resin on said space surfaces, curing said layers of resin, and introducing a thermosetting foamable core composition into a cavity defined by said spaced surfaces such that the thermosetting core composition substantially fills said cavity and integrally adheres to said opposing spaced surfaces and outwardly projecting fibers thereon to provide an increased area of surface adhesion between the thermosetting core composition and each of said skin sheet fibers, and effecting curing of said thermosetting core composition.

Claim 7

A method of making a structural panel comprising the steps of supporting a pair of fiber-reinforced generally rigid skin sheets of substantially identical configuration in spaced relation, closing the marginal edge spaces between said spaced skin sheets along all but one edge portion thereof to define a closed cavity between said skin sheets except for said open edge portion, inserting deposit means through said open edge, introducing into said cavity a thermosetting foamable resin core composition through said deposit means, said deposit means being initially positioned to deposit said thermosetting foamable core material into the portion of the cavity furthest removed from said opening at a measured rate, said deposit means being thereafter moved in a direction generally transversely to the direction of entry of said deposit means into the cavity to scan the same, said scanning movement of the deposit means being continuously repeated to deposit said thermosetting foamable core material into said cavity to substantially fill the same, each successive scanning movement of the deposit means being effected to deposit a measured quantity of foamable core material onto the preceding deposit prior to curing of said preceding deposit, and curing the deposited thermosetting foamable core material within said cavity to form an integral core connected to said skin sheets.

Claim 8

A method of making a structural panel comprising the steps of supporting a pair of fiber-reinforced generally rigid skin sheets of substantially identical configuration in spaced relation, closing the marginal edge spaces between said spaced skin sheets along all but one edge portion thereof to define a closed cavity between said skin sheets except for said open edge portion, inserting deposit means through said open edge, introducing into said cavity a thermosetting foamable resin core composition through said deposit means, said deposit means being initially positioned to deposit said thermosetting foamable core material into the portion of the cavity furthest removed from said opening at a measured rate, said deposit means being thereafter moved in a direction generally transversely to the direction of entry of said deposit means into the cavity to scan the same, said scanning movement of the deposit means being continuously repeated to deposit said thermosetting foamable core material into said cavity to substantially fill the same, each successive scanning movement of the deposit means being effected to deposit a measured quantity of foamable core material onto the preceding deposit prior to curing of said preceding deposit, and curing the deposited thermosetting foamable core material within said cavity to form an integral core connected to said skin sheets.

Claim 12

The method of making a structural panel having side skin sheets and a core integrally sandwiched therebetween, comprising the steps of supporting a pair of side skin sheets in spaced relation to define a mold cavity therebetween, closing the mold cavity along at least three marginal side edges thereof by spacer means, inserting deposit means into said mold cavity for depositing a thermosetting foamable core material into the mold cavity, moving the deposit means in a scan direction across the width of the cavity while depositing core material, and effecting the deposit of said thermosetting foamable core material during said scanning movement of said deposit means at a constant material delivery rate in accordance with the equation Mr ht SD/Tr- Tret, and effecting the rate of scan of said deposit means in accordance with the equation Sr S/Tr-Tret; where Mr is the core material delivery rate measured in pounds per minute, h is the height in feet of rise of the expanded thermosetting foamable core material, t is the thickness of the cavity measured in feet, considered in a direction between the side skin surfaces, S is the length in feet of scan movement of the material depositing means or the width of the mold cavity, D is the density of the chosen thermosetting foamable core material after expansion and curing, Tr is the rise time in minutes for the selected thermosetting foamable core material, Tret is the time in minutes required to withdraw the depositing means for the next successive scan of the deposit means, and Sr is the rate in feet per minute of scan of the deposit means.

Claim 13

The method of making a structural panel having side skin sheets and a core integrally sandwiched therebetween, comprising the steps of supporting a pair of side skin sheets in spaced relation to define a mold cavity therebetween, closing the mold cavity along at least three marginal side edges thereof by spacer means, inserting deposit means into said mold cavity for depositing a thermosetting foamable core material into the mold cavity, moving the deposit means in a scan direction across the width of the cavity while depositing core material, and effecting the deposit of said thermosetting foamable core material during said scanning movement of said deposit means at a constant material delivery rate in accordance with the equation Mr ht SD/Tr- Tret, and effecting the rate of scan of said deposit means in accordance with the equation Sr S/Tr-Tret; where Mr is the core material delivery rate measured in pounds per minute, h is the height in feet of rise of the expanded thermosetting foamable core material, t is the thickness of the cavity measured in feet, considered in a direction between the side skin surfaces, S is the length in feet of scan movement of the material depositing means or the width of the mold cavity, D is the density of the chosen thermosetting foamable core material after expansion and curing, Tr is the rise time in minutes for the selected thermosetting foamable core material, Tret is the time in minutes required to withdraw the depositing means for the next successive scan of the deposit means, and Sr is the rate in feet per minute of scan of the deposit means.

Claim 14

A method of making a structural panel including fiber-reinforced skin sheets that engage with a thermosetting foamable core composition for use in building structures and the like, comprising the steps of applying a first layer of gel coat to each of a pair of mold surfaces having a configuration conforming to the desired outer configuration of the panel desired, applying a first layer of polyester resin onto said gel coats, applying a first layer of glass fiber roving onto said layers of polyester resin before curing thereof, forcing the glass fiber roving into each of said first layers of resin in a manner to impregnate the glass roving fibers into each of said first layers of resin, applying a second layer of polyester resin into the combined first layers of resin and fibers, applying a second layer of glass fibers onto each of said second layers of resin without forcing and before said second layers of resin are cured such that portions of the fibers of each of said second layers of fibers project outwardly from each of said second layers of resin to provide fiberreinforced side skin sheets having fibers projecting outwardly from the surfaces thereof, supporting the resulting pair of panel-like configuration fiber-reinforced side skin sheets in spaced relation to define a mold cavity having a thickness substantially equal to the thickness of the desired panel, closing said cavity along the marginal edge portions thereof except for an opening extending along one marginal edge portion to provide access to the interior of the mold cavity, each of said skin sheets having the outwardly projecting fibers of said second layers projecting outwardly from the surface thereof opposing the other spaced skin sheet, introducing a thermosetting foamable core composition into said cavity such that the thermosetting core composition substantially fills said cavity and integrally adheres to said opposing skin sheets and outwardly projecting fibers to provide a greater adhesion area between the core composition and each of said sKin sheet fibers, and effecting curing of said core composition.

Claim 15

A method of making a structural panel including fiber-reinforced skin sheets that engage with a thermosetting foamable core composition for use in building structures and the like, comprising the steps of applying a first layer of gel coat to each of a pair of mold surfaces having a configuration conforming to the desired outer configuration of the panel desired, applying a first layer of polyester resin onto said gel coats, applying a first layer of glass fiber roving onto said layers of polyester resin before curing thereof, forcing the glass fiber roving into each of said first layers of resin in a manner to impregnate the glass roving fibers into each of said first layers of resin, applying a second layer of polyester resin into the combined first layers of resin and fibers, applying a second layer of glass fibers onto each of said second layers of resin without forcing and before said second layers of resin are cured such that portions of the fibers of each of said second layers of fibers project outwardly from each of said second layers of resin to provide fiberreinforced side skin sheets having fibers projecting outwardly from the surfaces thereof, supporting the resulting pair of panel-like configuration fiber-reinforced side skin sheets in spaced relation to define a mold cavity having a thickness substantially equal to the thickness of the desired panel, closing said cavity along the marginal edge portions thereof except for an opening extending along one marginal edge portion to provide access to the interior of the mold cavity, each of said skin sheets having the outwardly projecting fibers of said second layers projecting outwardly from the surface thereof opposing the other spaced skin sheet, introducing a thermosetting foamable core composition into said cavity such that the thermosetting core composition substantially fills said cavity and integrally adheres to said opposing skin sheets and outwardly projecting fibers to provide a greater adhesion area between the core composition and each of said sKin sheet fibers, and effecting curing of said core composition.

Claim 17

A method of making a structural panel for use in building structures and the like, comprising the steps of supporting a pair of fiber-reinforced side skin sheets in spaced relation to define a mold cavity having a plan configuration and thickness substantially equal to the shape of the panel desired, closing said cavity along the marginal edge portions thereof except for an opening extending along one marginal edge portion to provide access to the interior of the mold cavity, each of said side skin sheets including a cured body of a panel-like configuration having a plurality of fibers projecting outwardly from the surface thereof opposing the other spaced skin sheet, inserting a deposit means into said cavity and moving said deposit means generally transversely to the direction of insertion to introduce a thermosetting foamable composition along a line of deposit into said cavity and withdrawing said deposit means after each successive transverse scan, each successive transverse scan being performed prior to curing of the thermosetting foamable composition previously deposited, such that the thermosetting foamable composition substantially fills said cavity and integrally adheres to said opposing skin sheets and outwardly projecting fibers to provide a greater adhesion area between the thermosetting foamable composition and each of said skin sheet fibers, and effecting curing of said thermosetting foamable composition.

Claim 18

A method of making a structural panel for use in building structures and the like, comprising the steps of supporting a pair of fiber-reinforced side skin sheets in spaced relation to define a mold cavity having a plan configuration and thickness substantially equal to the shape of the panel desired, closing said cavity along the marginal edge portions thereof except for an opening extending along one marginal edge portion to provide access to the interior of the mold cavity, each of said side skin sheets including a cured body of a panel-like configuration having a plurality of fibers projecting outwardly from the surface thereof opposing the other spaced skin sheet, inserting a deposit means into said cavity and moving said deposit means generally transversely to the direction of insertion to introduce a thermosetting foamable composition along a line of deposit into said cavity and withdrawing said deposit means after each successive transverse scan, each successive transverse scan being performed prior to curing of the thermosetting foamable composition previously deposited, such that the thermosetting foamable composition substantially fills said cavity and integrally adheres to said opposing skin sheets and outwardly projecting fibers to provide a greater adhesion area between the thermosetting foamable composition and each of said skin sheet fibers, and effecting curing of said thermosetting foamable composition.