Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating or impregnation specified as porous or permeable to...
Reexamination Certificate
1999-06-24
2002-09-17
Copenheaver, Blaine (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Coating or impregnation specified as porous or permeable to...
C428S904000, C442S065000, C442S066000, C442S168000, C442S340000
Reexamination Certificate
active
06451716
ABSTRACT:
TECHNICAL FIELD
The present invention relates to leatherlike sheet, materials thin in thickness, rich in softness, having low impact resilience and high strength, and having a resemblance to kangaroo-leather, and a method for producing same. More particularly, the present invention concerns leatherlike sheet materials having high peel-off strength between layers, excellent in air permeability and moisture permeability, and having a kangaroo-like design, and a method for producing same.
BACKGROUND ART
Heretofore, various proposals have been made for leatherlike sheet materials having softness like natural leathers. For example, Japanese Patent Publication No. 63-5518 has proposed the following processes: an entangled nonwoven fabric comprising ultrafine fibers having single fineness of no greater than 1 de is impregnated with a polyurethane resin, then the nonwoven fabric is subjected to wet-type coagulation to obtain a base material, on the base material is laminated a film prepared by applying a polyurethane resin on a release paper, or on the base material is applied a polyurethane solution, the resultant polyurethane resin-coated nonwoven fabric is subjected to a wet-type coagulation treatment again, and subsequently a polyurethane resin-based colored coating material is applied by a gravure roll; or an entangled nonwoven fabric comprising islands-in-a-sea type multi-component fibers is impregnated with a polyurethane resin, the resultant polyurethane resin-impregnated nonwoven fabric is subjected to a wet-type coagulation treatment, subsequently one component of the multi-component fiber is dissolved by a solvent or the like to remove the component to convert the fibers into ultrafine-fiber bundles having a single fineness of no greater than 0.2 de, and then the above-mentioned surface finishing processing is applied on the base material comprising the ultrafine-fiber bundles. The leatherlike sheet materials obtained by these processes have properties close to natural leathers in softness. However, a leatherlike sheet material having softness, body feeling (stiffness) and leather-like low resiliency at the same time, and further having good air permeability and moisture permeability has not been obtained yet.
Further, as a manmade leather which is soft and has body feeling (stiffness); Japanese Unexamined Patent Publication No. 4-185777 has proposed a sheet material which is prepared by using a high density nonwoven fabric and in which the amount of the impregnated resin is controlled to a low level. However, the proposed sheet material is short in soft feeling of the surface, insufficient in a peel-off strength between layers as for a material for shoes which is used under severe conditions, and also poor in air permeability and moisture permeability.
The object of the present invention is to provide leatherlike sheet materials thin in thickness, rich in softness, having low impact resilience and high strength, and having a kangaroo-like design; more particularly leatherlike sheet materials having high peel-off strength between layers, excellent in air permeability and moisture permeability, and having a kangaroo-like design, and to provide a method for producing same.
DISCLOSURE OF THE INVENTION
The inventors of the present invention have pursued extensive investigations for achieving the above-mentioned objects by finding a leatherlike sheet material which has a base material (I) comprising a nonwoven fabric (A) constituted with ultrafine-fiber bundles having single fineness of no greater than 0.2 de, a high molecular elastomer (B) and a high molecular elastomer (C), and in which a grained surface layer (II) comprising a high molecular elastomer (C)-constituted surface porous layer (D) and a surface finishing layer (E) is formed on at least one side of the surfaces of the base material (I), wherein the leatherlike sheet material is characterized in that
(1) the apparent density of the base material (I) is 0.37 to 0.65 g/cm
3
,
(2) the weight ratio of the nonwoven fabric (A) to the high molecular elastomer (B) and the high molecular elastomer (C) in the base material ( I) is 45:55 to 69:31,
(3) the thickness of the grained surface layer (II) is 0.01 to 0.18 mm, and
(4) the ratios of 20%-elongation load ((&sgr;20)/5%-elongation load (&sgr;5) in the longitudinal direction and the transverse direction of the leatherlike sheet material are each not less than 5 nor more than 20, and further by finding a method for producing same.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereafter, the present invention will be explained in detail.
A leatherlike sheet material used in the present invention has a base material (I) comprising a nonwoven fabric (A) constituted with ultrafine fiber bundles having single fineness of no greater than 0.2 de, a high molecular elastomer (B) and the high molecular elastomer (C), and a grained surface layer (II) comprising a high molecular elastomer (C)-constituted surface porous layer (D) and a surface finishing layer (E) is formed on at least one side of the surfaces of the base material (I).
The nonwoven fabric (A) constituting the base material (I) of the leatherlike sheet material comprises ultrafine-fiber bundles having single fineness of no greater than 0.2 de. Examples of a high molecular polymer which forms the ultrafine fibers include polyamides such as nylon 6, nylon 66 and nylon 12, and polyesters such as polyethylene terephthalate and polybutylene terephthalate. Single fineness of the ultrafine fibers is no greater than 0.2 de, preferably no greater than 0.1 de, especially preferably 0.0001 to 0.05 de. The single fineness used here may be an average single fineness. The ultrafine fibers must be used in the form of bundles, and one bundle contains preferably 10 to 5000 ultrafine fibers, further preferably 100 to 2000.
Examples of the high molecular elastomer (B) include a polyurethane elastomer, polyurea elastomer, polyurethane polyurea elastomer, polyacrylic acid resin, acrylonitrile.butadiene elastomer, styrene butadiene elastomer and the like. Among them are preferable polyurethane group elastomers such as a polyurethane elastomer, polyurea elastomer and polyurethanepolyurea elastomer. These polyurethane elastomers are obtained by reacting one kind, or two or more kinds of polymeric glycols selected from polyether glycols, polyester glycols, polyesterether glycols, polycaprolactone glycols, polycarbonate glycols and the like having average molecular weight of 500 to 4000 with an organic diisocyanate such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate, and a chain extender selected from low molecular glycols, diamines, hydrazine derivatives such as hydrazine, organic acid hydrazides and amino acid hydrazides, and the like. The 100%-elongation modulus of the high molecular weight elastomer (B) is preferably 40 to 300 kg/cm
2
. When the 100%-elongation modulus is less than 40 kg/cm
2
, the obtained leatherlike sheet material is rich in softness, but it is poor in heat resistance, solvent resistance and the like, and on the other hand, when the 100%-elongation modulus exceeds 300 kg/cm
2
, the obtained leatherlike sheet material has hard touch, and hence these cases are not preferable. The adjustment of the 100%-elongation modulus of the high molecular elastomer (B) into the preferable range can be easily attained, for example, by adjusting the amounts of organic diisocyanate and chain extender in the polymer when a polyurethane elastomer is used as the high molecular elastomer (B).
The impregnation of the high molecular elastomer (B) into a nonwoven fabric is generally carried out by using a solution or dispersion (including aqueous emulsion) of the high molecular elastomer (B) in an organic solvent. Here, as the solution containing a solvent for the high molecular elastomer (B), it is preferable to use a solution comprising a good solvent for the high molecular elastomer (B) such as dimethylformamide, diethylformamide, dimethylacetamide o
Sasaki Kunihiko
Suzuki Yoshiyuki
Copenheaver Blaine
Pratt Christopher L.
Sughrue & Mion, PLLC
Teijin Limited
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