Interior Finishing Panel for Vehicle and Method of Manufacturing the Same

Abstract

An interior finishing panel for a vehicle, comprising a first wall) and a second wall opposed to each other at an interval. The panel is formed in a hollow double wall structure having an inner rib formed between the first wall and the second wall. A skin sheet with an averaged thickness of 2.0 mm or thinner is integrally laminated on the first wall. The skin sheet is formed in a double layer structure in which a nonwoven cloth with a weight of 250 g/m<2> or less is stuck on a resin sheet, and its tensile elastic modulus at room temperature is 3500 kg/cm<2> or less. A parting line and a step part are formed on a peripheral wall within the range of 35% of the averaged thickness of the panel from the first wall side over roughly all the periphery thereof, and the end of the skin sheet is melt-bonded to the peripheral wall along the step part. A three-dimensional pattern is produced on the surface of the resin sheet forming the skin sheet.

1 . A vehicle interior panel having a hollow double-walled structure which is made of a thermoplastic resin by blow molding, wherein the vehicle interior panel has a peripheral wall which forms a hollow space between a first wall and a second wall in the hollow double-walled structure, the first wall and the second wall facing each other, a parting line is formed over a substantially entire circumference on the peripheral wall, a cover material is integrally laminated to the first wall, an average thickness of the cover material being no more than 2.0 mm, tensile modulus of the cover material being no more than 3500 kg/cm 2  at room temperature, the cover material is formed by at least a double-layer structure in which a non-woven fabric whose weight per area is no more than 250 g/m 2  is laminated to the resin sheet, and a three-dimensional pattern including projections, recesses, or projections and recesses emerge on a surface of the resin sheet. 
   
   
       2 . A vehicle interior panel according to  claim 1 , wherein the resin sheet is made of polyvinyl chloride or olefin elastomer, and a through hole is not made in the resin sheet. 
   
   
       3 . A vehicle interior panel according to  claim 1 , wherein tensile modulus of the cover material is lower than 2000 kg/cm 2  at room temperature. 
   
   
       4 . A vehicle interior panel according to  claim 1 , wherein tensile modulus of the cover material is lower than 500 kg/cm 2  at 100° C., and a tensile strength at yield point of the cover material is no more than 50 kg/cm 2  at 100° C. 
   
   
       5 . A vehicle interior panel according to  claim 1 , wherein the three-dimensional pattern is a plurality of substantially hemispherical protrusions which have heights ranging from 0.5 to 2.5 mm. 
   
   
       6 . A vehicle interior panel according to  claim 1 , characterized in that the cover material is integrally laminated to the first wall while the blow molding, and the cover material has the three-dimensional pattern generated by transferring a pattern of a cavity surface to the surface of the resin sheet by pressing the resin sheet against the mold. 
   
   
       7 . A vehicle interior panel according to  claim 1 , wherein an average thickness (a) of the vehicle interior panel is formed no more than 25.0 mm and, on the peripheral wall connecting the first wall and the second wall, the parting line is formed at a position located within a 35% range (b) of the average thickness of the panel from the surface of the first wall, or the parting line is formed within the range in which the thickness is no more than 8.0 mm from the surface of the first wall. 
   
   
       8 . A vehicle interior panel according to  claim 7 , wherein a step portion is formed over the substantially entire circumference at a portion on the first wall side of the parting line formed on the peripheral wall, and an end of the cover material laminated to the surface of the first wall while the blow molding is laminated along the step portion. 
   
   
       9 . A vehicle interior panel according to  claim 8 , wherein a width of the step portion is at least 1.0 mm. 
   
   
       10 . A vehicle interior panel according to  claim 8 , wherein a portion connecting the step portion of the peripheral wall and the first wall is formed in a loose curved surface. 
   
   
       11 . A vehicle interior panel according to  claim 1 , wherein an double-walled rib having a plate-like structure is formed between the first wall and the second wall by protruding a part of the second wall toward the first wall to be integrally welded to the backside of the first wall and integrally welding the protruded portions to each other in the plate-like structure. 
   
   
       12 . A vehicle interior panel according to  claim 11 , wherein a groove which is shallower than a wall thickness of the panel is formed on the surface of the second wall corresponding to a region where the double-walled rib is formed. 
   
   
       13 . A vehicle interior panel according to  claim 11 , wherein a series of weld ribs is provided at an end portion in a longitudinal direction of said double-walled rib, a part of the second wall being protruded toward the first wall to be integrally welded to the backside of the first wall and the protruded portion being formed in the concave shape in the weld rib. 
   
   
       14 . A vehicle interior panel according to  claim 1 , wherein a thin hinge portion separating the hollow spaces is formed in between the first wall and the second wall by protruding a part of the second wall toward the first wall and integrally welded to the backside of the first wall in the hinge portion, and the parting line is formed on the peripheral wall connecting the first wall and the second wall, the parting line including a substantially linear portion and a portion close to the first wall side in the vicinity of the hinge portion. 
   
   
       15 . A vehicle interior panel according to  claim 14 , wherein the first wall is substantially formed in flat, and the hinge portion is formed in the substantially same surface as the first wall. 
   
   
       16 . A vehicle interior panel according to  claim 14 , characterized in that a plurality of double-walled ribs having the plate-like structures are formed between the first wall and the second wall by protruding a part of the second wall toward the first wall to be integrally welded to the backside of the first wall and integrally welding both side faces of the protruded portions to each other in the plate-like structure, and the double-walled rib is substantially formed in parallel with the hinge portion. 
   
   
       17 . A method of producing a vehicle interior panel having a hollow double-walled structure made of thermoplastic by blow molding with a pair of mold halves including one mold and the other mold, wherein clamping is performed while a cover material is arranged between a cavity of one mold and a parison of thermoplastic such that a resin sheet faces a cavity, the cover material is made by bonding a non-woven fabric whose weight per area is no more than 250 g/cm 2  to the resin sheet having no through hole, an average thickness of the cover material being not more than 2.0 mm, tensile modulus of the cover material being lower than 500 kg/cm 2  at 100° C., a tensile strength at yield point of the cover material being not more than 50 kg/cm 2  at 100° C., a pressurized fluid is introduced into the parison to press the cover material and the parison against a cavity surface, and thereby the vehicle interior panel in which said cover material is integrally laminated to an outer surface of a first wall of the panel having the hollow double-walled structure is formed. 
   
   
       18 . A vehicle interior panel producing method according to  claim 17 , wherein a pinch-off forming portions forming a boundary between said cavities are provided in one mold and the other mold, the parison and the cover material are sandwiched by arranging the parison and the cover material between the mold halves to perform the clamping, a blowing pin is stick into the parison near the pinch-off forming portions to introduce the pressurized fluid in the parison, a parting line corresponding to the pinch-off forming portions is formed, an end of the cover material is integrally laminated along the parting line over a substantially entire circumference of a peripheral wall of the vehicle interior panel. 
   
   
       19 . A vehicle interior panel producing method according to  claim 18 , wherein a step-portion forming portion is provided along the pinch-off forming portion over the substantially entire circumference of the cavity in one mold, the end of the cover material is integrally fixed by pressing the end of the cover material against the parison in the step-portion forming portion, and thereby the end of the cover material is laminated along a step portion formed on the peripheral wall of the vehicle interior panel. 
   
   
       20 . A vehicle interior panel producing method according to  claim 17 , wherein a slide core is provided in the cavity of the other mold while being retractable to a cavity surface, after a part of the parison is integrally welded by the slide core projected from the cavity surface, the slide core is retracted to the cavity of the other mold, and the pressurized fluid is introduced into the parison to form a double-plate-like double-walled rib in which side faces are welded to each other between the first wall and a second wall by blow pressure. 
   
   
       21 . A vehicle interior panel producing method according to  claim 17 , wherein a hinge forming portion is provided on the cavity of the other mold, the cavity of the other mold has a parting surface including a substantially linear pinch-off forming portion and a pinch-off forming portion projected from the cavity surface near the hinge forming portion, the cavity of one mold has the parting surface including a substantially linear pinch-off forming portion and a pinch-off forming portion corresponding to said projected pinch-off forming portion, the cover material is arranged between the parison and one mold, the mold halves are clamped to form the parting line corresponding to said parting surface, parts of the parison are integrally welded by the hinge forming portion provided in the other mold, and the pressurized fluid is introduced into the parison to form a hinge portion separating hollow spaces in the substantially same surface as the first wall by the blow pressure. 
   
   
       22 . A vehicle interior panel producing method according to  claim 17 , wherein the mold half in which a three-dimensional shape transfer surface is formed is used as at least one mold, the parison is arranged between said mold halves, the substantially flat cover material having no three-dimensional pattern is arranged between the parison and the cavity in which said three-dimensional shape transfer surface is formed such that the resin sheet faces the cavity, the mold halves are closed to introduce the pressurized fluid into the parison, the cover material is pressed against the cavity of one mold to laminate the cover material to the parison, and the three-dimensional pattern corresponding to said three-dimensional shape transfer surface is transferred to the surface of the cover material. 
   
   
       23 . A vehicle interior panel producing method according to  claim 22 , wherein the three-dimensional shape transfer surface has a grain pattern or a plurality of recesses whose depths from the cavity surface range from 0.5 to 2.5 mm. 
   
   
       24 . A vehicle interior panel producing method according to  claim 22 , wherein the cover material is arranged between the parison and the cavity of one of the mold halves, and clamping is performed without softening the cover material by a heating process.