Sheet elastic complex used in sanitary products its manufacturing process, and its usages

A sheet elastic complex

• comprising first and second non-elastic backing sheets which have been bonded along multiple, oblong, mutually parallel bonding sections to opposing surfaces of a planar elastic sheet under heating conditions, the width of each of the backing sheets between adjacent ones of said bonding sections being greater than that of said elastic sheet to form channels in combination with the planar elastic sheet, wherein said bonding sections have a width X, and non-bonding sections between said bonding sections have a width Y, with the ratio ##EQU2## being less than 50%, and wherein Q is the length between said bonding sections in a stretched state of said sheet elastic complex, and P is the length between said bonding sections in a relaxed state of said sheet elastic complex, and a ratio of Q/P is equal to or greater than 1.5.

A stretchable sheet composite comprising:

• a non-elastic sheet having an expansive surface formed by stretching the sheet past its extension limits in a direction orthogonal to the lengthwise direction of parallel bonding regions between the non-elastic sheet and an elastic sheet;
• and
• said elastic sheet being essentially uniaxially stretchable, said elastic sheet having been heat-bonded in a relaxed state to said surface of the non-elastic sheet resulting in the formation of a number of substantially parallel, elongated bonding regions extending transverse to said axial direction of stretch to define bond-free regions between adjacent parallel bonding regions in said stretchable sheet composite, wherein said bonding regions have a width X, and said bond-free regions have a width Y, with the ratio ##EQU5## being less than 50%, and wherein Q is the length between said bonding regions in a stretched state of said sheet composite, and P is the length between said bonding regions in a relaxed state of said sheet composite and a ratio of Q/P is equal to or greater than 1.5.

A stretchable sheet composite comprising:

• an elastic sheet having been heat-bonded to a non-elastic, non-woven fabric by a number of substantially parallel, elongated bonding regions extending in one direction to define bond-free, stretchable regions between adjacent parallel bonding regions in said stretchable sheet composite, such stretchable sheet composite being more stretchable transverse to said bonding regions than along said bonding regions, said non-elastic, non-woven fabric sheet having been stretched beyond its extension limit in a direction orthogonal to the lengthwise direction of said parallel bonding regions, wherein said bonding regions have a width X, and said bond-free regions have a width Y, with the ratio ##EQU6## being less than 50%, and wherein Q is the length between said bonding regions in a stretched state of said sheet composite, and P is the length between said bonding regions in a relaxed state of said sheet composite and a ratio of Q/P is equal to or greater than 1.5.

A stretchable compositive material comprising:

• a pair of stretchable sheet composites, each of said sheet comprising a non-elastic sheet, and an elastic sheet intermittently bonded to said non-elastic sheet at a number of parallel securement portions to define non-secured, stretchable portions of each said sheet composites,
• said pair of stretchable sheet composites being superposed to each other by joining said elastic sheets pair of composites to each other so as to flank said elastic sheets between said non-elastic sheets, each of said non-elastic sheets having been stretched beyond its extension limit in a direction orthogonal to the lengthwise direction of said parallel securement portions, wherein said securement portions have a width X, and said non-secured portion have a width Y, with the ratio ##EQU7## being less than 50%, and wherein Q is the length between said securement portions in a stretched state of each said sheet composite,and P is the length between said securement portions in a relaxed state of said sheet composite and a ratio of Q/P is equal to or greater than 1.5.

A process for manufacturing a sheet elastic complex which includes a non-elastic backing sheet material on at least one side of an elastic body sheet, comprising the steps of:

• bonding the backing sheet material and elastic body sheet at multiple, oblong, and mutually parallel bonding sections under heating conditions;
• and forming multiple, mutually parallel channels between the backing sheet material and the elastic body sheet, the channels being formed through stretching the backing sheet material past its extension limit in a direction orthogonal to the lengthwise direction of the bonding sections, thus ensuring that the width of the backing sheet material between the mutually adjacent bonding sections is greater than that of the elastic body sheet, wherein said bonding sections have a width X, and non-bonding sections between said bonding sections have a width Y, with the ratio ##EQU9## being less than 50%, and wherein Q is the length between said bonding sections in a stretched state of said sheet elastic complex, and P is the length between said bonding sections in a relaxed state of said sheet elastic complex, and a ratio of Q/P is equal to or greater than 1.5.

A process for manufacturing a sheet elastic complex which includes drawing an elastic body sheet from a roll;

• bonding each non-elastic backing sheet material to the elastic body sheet at multiple, oblong, and mutually parallel bonding sections by bonding the three-ply complex from both sides using a heated grid roll having protrusions which extend in the axial direction;
• and forming multiple, mutually parallel channels between the non-elastic backing sheet material and the elastic body sheet, the channels being formed through stretching the non-elastic backing sheet material past its extension limit in a direction orthogonal to the lengthwise direction of the bonding sections, thus ensuring that the width of the backing sheet material between the mutually adjacent bonding sections is greater than that of the elastic body sheet, wherein said bonding sections have a width X, and non-bonding sections between said bonding sections have a width Y, with the ratio ##EQU10## being less than 50%, and wherein Q is the length Y, with the bonding sections in a stretched state of said sheet elastic complex, and P is the length between said bonding sections in a relaxed state of said sheet elastic complex, and a ratio of Q/P is equal to or greater than 1.5.

A method of manufacturing a uniaxially stretchable, sheet composite comprising the steps of:

• feeding a continuous, uniaxially stretchable elastic sheet in the direction transverse to said uniaxial direction so that said elastic sheet is introduced in a substantially relaxed state;
• introducing a continuous, non-elastic sheet in the direction transverse to said uniaxial direction in juxtaposition with said stretchable elastic sheet;
• heat-bonding said elastic sheet in the relaxed state to said non-elastic sheet to form a number of intermittent parallel heat-bonding regions and stretching the non-elastic sheet of the bonded composite beyond its extension limit in a direction orthogonal to the longitudinal direction of the parallel bonding regions, wherein said heat-bonding regions have a width X, and said bond-free regions have a width Y, with the ratio ##EQU11## being less than 50%, and wherein Q is the length between said heat-bonding regions in a stretched state of each said stretchable sheet composite, and P is the length between said heat-bonding regions in a relaxed state of said stretchable sheet composite and a ratio of Q/P is equal to or greater than 1.5.