Method of manufacturing a plastic motor vehicle door

Claim 2

In a sequential reaction injection molding method of manufacturing a glass fiber mat reinforced plastic part having at least one appearance surface in which a high viscosity reaction injection molding material and a low viscosity reaction injection molding material are sequentially injected into a mold cavity containing at least one reinforcing member of a glass fiber mat, said method comprising the steps of: loading said at least one reinforcing member of a glass fiber mat into said mold cavity; injecting a first reaction injection molding material at room temperature into said mold cavity forming said at least one appearance surface, said first reaction injection molding material having a room temperature viscosity too high to substantially penetrate through said at least one reinforcing member of a glass fiber mat; injecting a second reaction injection molding material at room temperature into said mold cavity to substantially penetrate through said at least one reinforcing member of a glass fiber mat and causing a bond to be formed between said first and said second reaction injection molding material, said second reaction injection molding material having a lower room temperature viscosity than that of said first reaction injection molding material prior to said injection process; curing said plastic part in said mold cavity for a sufficient length of time; and demolding said cured part from said mold cavity.

Claim 3

In a sequential reaction injection molding method of manufacturing a glass fiber mat reinforced plastic part having at least one appearance surface in which a high viscosity reaction injection molding material and a low viscosity reaction injection molding material are sequentially injected into a mold cavity containing at least one reinforcing member of a glass fiber mat, said method comprising the steps of: loading said at least one reinforcing member of a glass fiber mat into said mold cavity; injecting a first reaction injection molding material at room temperature into said mold cavity forming said at least one appearance surface, said first reaction injection molding material having a room temperature viscosity too high to substantially penetrate through said at least one reinforcing member of a glass fiber mat; withdrawing air from said mold cavity to a pressure of no higher than 20 inches of mercury; injecting a second reaction injection molding material at room temperature into said mold cavity to substantially penetrate through said at least one reinforcing member of a glass fiber mat and causing a bond to be formed between said first and said second reaction injection molding material, said second reaction injection molding material having a lower room temperature viscosity than that of said first reaction injection molding material prior to said injection process; curing said plastic part in said mold cavity for a sufficient length of time; and demolding said cured part from said mold cavity.

Claim 4

In a sequential reaction injection molding method of manufacturing a glass fiber mat reinforced plastic part having at least one appearance surface in which a high viscosity reaction injection molding material and a low viscosity reaction injection molding material are sequentially injected into a mold cavity containing at least one reinforcing member of a glass fiber mat, said method comprising the steps of: loading said at least one reinforcing member of a glass fiber mat into said mold cavity; injecting a first reaction injection molding material at room temperature into said mold cavity forming said at least one appearance surface, said first reaction injection molding material having a room temperature viscosity too high to substantially penetrate through said at least one reinforcing member of a glass fiber mat; withdrawing air from said mold cavity to a pressure of no higher than 20 inches of mercury; injecting a second reaction injection molding material at room temperature into said mold cavity to substantially penetrate through said at least one reinforcing member of a glass fiber mat and causing a bond to be formed between said first and said second reaction injection molding material, said second reaction injection molding material having a lower room temperature viscosity than that of said first reaction injection molding material prior to said injection process; curing said plastic part in said mold cavity for a sufficient length of time; and demolding said cured part from said mold cavity.

Claim 5

In a sequential reaction injection molding method of manufacturing a glass fiber mat reinforced plastic part having at least one appearance surface in which a high viscosity reaction injection molding material and a low viscosity reaction injection molding material are sequentially injected into a mold cavity containing at least one reinforcing member of a glass fiber mat, said method comprising the steps of: loading said at least one reinforcing member of a glass fiber mat into said mold cavity; injecting a first reaction injection molding material at room temperature into said mold cavity forming said at least one appearance surface, said first reaction injection molding material having a room temperature viscosity too high to substantially penetrate through said at least one reinforcing member of a glass fiber mat; withdrawing air from said mold cavity to a pressure of no higher than 15 in. Mercury; injecting a second reaction injection molding material at room temperature into said mold cavity to substantially penetrate through said at least one reinforcing member of a glass fiber mat and causing a bond to be formed between said first and said second reaction injection molding material, said second reaction injection molding material having a room temperature viscosity no more than half of that of said first reaction injection molding material prior to said injection process; curing said plastic part in said mold cavity for a sufficient length of time; and demolding said cured part from said mold cavity.

Claim 6

In a sequential reaction injection molding method of manufacturing a glass fiber mat reinforced plastic part having at least one appearance surface in which a high viscosity reaction injection molding material and a low viscosity reaction injection molding material are sequentially injected into a mold cavity containing at least one reinforcing member of a glass fiber mat, said method comprising the steps of: loading said at least one reinforcing member of a glass fiber mat into said mold cavity; injecting a first reaction injection molding material at room temperature into said mold cavity forming said at least one appearance surface, said first reaction injection molding material having a room temperature viscosity too high to substantially penetrate through said at least one reinforcing member of a glass fiber mat; withdrawing air from said mold cavity to a pressure of no higher than 15 in. Mercury; injecting a second reaction injection molding material at room temperature into said mold cavity to substantially penetrate through said at least one reinforcing member of a glass fiber mat and causing a bond to be formed between said first and said second reaction injection molding material, said second reaction injection molding material having a room temperature viscosity no more than half of that of said first reaction injection molding material prior to said injection process; curing said plastic part in said mold cavity for a sufficient length of time; and demolding said cured part from said mold cavity.

Claim 7

In the method of claim 1, said first and said second reaction injection molding material comprises a polyurethane.

Claim 8

In the method of claim 2, said at least one reinforcing member further includes a preformed tubular member of generally inverted U shape defining the window frame of a motor vehicle door.