Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Nonwoven fabric has an elastic quality
Reexamination Certificate
2000-07-19
2002-08-06
Seidleck, James J. (Department: 1711)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Nonwoven fabric has an elastic quality
C442S328000, C442S329000, C428S221000, C528S045000
Reexamination Certificate
active
06429159
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a stretchable adhesive nonwoven fabric having an excellent adhesive strength as well as air permeability and flexibility.
BACKGROUND ART
A hot-melt nonwoven fabric is used to laminate the nonwoven fabric with the adherend, and fuse the nonwoven fabric with heating to bond it. As the hot-melt nonwoven fabric, those made of a resin such as ethylene-vinyl acetate copolymer (EVA), polyethylene-atactic polypropylene (APP), ethylene-ethyl acrylate copolymer (EEA), polyamide, polyester or the like has hitherto been known.
The resin constituting the hot-melt nonwoven fabric is incorporated with plasticizers, tackifiers and waxes, and is put into practice to improve various performances which are generally required for use as an adhesive material. However, such a nonwoven fabric is poor in chemical resistance, thermal resistance, cleaning resistance and flexibility causing impairment of laminates to cause a problem that the pleasant feel to the touch of the laminate is drastically impaired.
As a method of solving these problems, for example, a method of forming a thermoplastic polyurethane resin into a film and using the film as an adhesive material has been disclosed in Unexamined Patent Publication (Kokai) Nos. 7-97560 and 9-221640.
However, the film made of the thermoplastic polyurethane resin causes a problem air permeability of the laminate is drastically lowered or completely lost.
An object of the present invention is to solve these problems of previously known arts and provide a stretchable adhesive nonwoven fabric, which is rich in flexibility and is excellent in adhesive properties and air permeability.
DESCRIPTION OF THE INVENTION
The present inventors have intensely studied to solve these previous problems. As a result, they have made an invention relating to a stretchable adhesive nonwoven fabric prepared by laminating continuous filaments made of a thermoplastic polyurethane resin, which comprises an aliphatic diisocyanate and/or an aromatic diisocyanate, a polymeric diol and a chain-extending agent and has a hardness (JIS-A hardness) of 65 to 98 degrees and a flow initiating temperature within a range from 80 to 150° C., into a sheet, and fusion-bonding the filaments themselves with their own heat at the contact point of the laminated filaments thereby to form fibers.
BEST MODE FOR CARRYING OUT THE INVENTION
The aliphatic diisocyanate used in the present invention is preferably an aliphatic diisocyanate having 4 to 13 carbon atoms. Examples thereof include straight-chain diisocyanates such as 1,4-tetramethylene diisocyanate, 1,5,-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,8-octamethylene diisocyanate and isophorone diisocyanate; and alicyclic diisocyanates such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornane-diisocyanate methyl. An aliphatic diisocyanate having a methyl side chain in a molecule, for example, trimethyl-hexamethylene diisocyanate, methylbutane diisocyanate, methylpentane diisocyanate or the like is also preferably used.
They can be used alone or in combination with the above diisocyanates having no side chain.
Examples of the aromatic diisocyanate used in the present invention include 2,4-torilene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, phenylene diisocyanate, 1,5-naphthalene diisocyanate or the like.
The polymeric diol used in the present invention include, for example, polymeric diol having no side chain such as polyester diol prepared from various straight-chain low monomeric diols and dicarboxylic acids such as adipic acid, phthalic acid, sebacic acid and dimeric acid; polycaprolactonediol; carbonates of various glycols; and polyether diols such as polytetromethylene glycol.
Examples of the polymeric diol having a methyl side chain in a molecule include polyester diol prepared from side-chain diol alone, such as 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 2-methyl-1,5-hexanediol, 3-methyl-1,5-hexanediol, neopenthyl glycol, 3-methyl-1,5-pentanediol and 2-methyl-1,8-octanediol, or a mixture with straight-chain diol, and dicarboxylic acids; polyvalerolactonediols made of &bgr;-methyl-&dgr;-valerolactone having a methyl side chain and the like. These compounds can be used alone or in combination with the above polymeric diols having no side chain. The number average molecular weight of these polymeric diols are within a range from 500 to 10,000, and preferably from 700 to 8,000.
The chain-extending agent used in the present invention includes, for example, a diol compound having a molecular weight of not more than 400. Specific compounds include ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanedilo, 1,9-nonanediol, bis-&bgr;-hydroxyethoxybenzene and the like. There can also preferably be used side-chain diols such as 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 2-methyl-1,5-hexanediol, 3-methyl-1,5-hexanediol, neopenthyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, N-phenyldiisopropanolamine and the like. They can be used alone or in combination.
The thermoplastic polyurethane resin in the present invention is required to have a flow initiating temperature within a range from 80 to 150° C. When the flow initiating temperature is less than 80° C., it becomes difficult to prepare a nonwoven fabric by hot molding. On the other hand, when the flow initiating temperature excesses 150° C., the flexibility of the nonwoven fabric is lost and the temperature on bonding rises to cause discoloration of the adherend so that it becomes unsuitable for use as an adhesive material for clothing.
As used herein, the term “flow initiating temperature” refers to a temperature at which a resin initiates to melt and flow when heating at a constant heating rate. It is usually measured by, for example, a flow tester. The flow initiating temperature is an important physical property because it limits bonding conditions of a hot-melt nonwoven fabric adhesive material, especially heating temperature.
The hardness (JIS-A hardness) of the thermoplastic polyurethane resin of the present invention is required to be within a range from 65 to 98 degree. When the hardness is less than 65 degree, it becomes difficult to prepare a nonwoven fabric by heat molding. On the other hand, the hardness excesses 98 degree, the flexibility of the nonwoven fabric is lost so that it is not suited for used as an adhesive material for clothing.
By using, as at least one component of components of the thermoplastic polyurethane resin used in the present invention, a polymeric diol which has one or more methyl side chains, in particular has repeat units having a side chain in the molecule, it becomes possible to impart more excellent cold temperature flexibility, which is preferred. The cold temperature flexibility can be evaluated by a change between the hardness at normal temperature and that at cold temperature. A nonwoven fabric having excellent cold temperature flexibility is preferred because the pleasant feel to the touch is hardly deteriorated.
As the method preparing the thermoplastic polyurethane resin used in the present invention, for example, there can be employed any known methods of preparing the thermoplastic polyurethane resin, such as one shot method, prepolymer method, batch method, continuous method, extruder method, kneader method and the like. For example, according to the method using a kneader, a thermoplastic polyurethane resin in the form of flakes can be prepared by charging a polymeric diol and a chain-extending agent in a kneader, heating the mixture to 60° C., charging an aliphatic diisocyanate, reacting the mixture for 10 to 60 minutes, and cooling the resultant. A block can be ground into flakes by using a grinder. These flakes are optionally formed into pellets by extruder.
Use of a catalyst on the preparation of the thermoplastic polyurethane resin of the present invention is not necessary, however, there can be used tertiary amines such as triethylamine and triethylene
Kawada Teruyoshi
Tanaka Yutaka
Teshima Tsutomu
Watanabe Noboru
Yamakawa Yukio
Kanebo Limited
Morgan & Finnegan , LLP
Ribar Travis B
Seidleck James J.
LandOfFree
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