Bleaching and dyeing; fluid treatment and chemical modification – Chemical modification of textiles or fibers or products thereof
Reexamination Certificate
1999-02-17
2002-02-12
Gupta, Yogendra N. (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Chemical modification of textiles or fibers or products thereof
C008S116400, C428S393000, C428S392000, C428S027000, C428S067000, C428S298100, C428S339000
Reexamination Certificate
active
06346125
ABSTRACT:
The present invention relates to a process for the treatment of nonwovens with antimicrobial agents, a process for the preparation of a formulation comprising the antimicrobial agents and the nonwovens treated by this method.
“Non-woven” is a type of fabric that is not spun and woven into a cloth, but instead bonded together. According to the ISO definition it is a manufactured sheet, web, or batt of directionally or randomly orientated fibres, bonded by friction, and/or adhesion.
Nonwoven textiles are widely used in disposable as well as durable goods, such as baby diaper, feminine hygiene, adult incontinence, wipers, bed linings, automotive industries, medical face masks, air and water filtration, home furnishing and geotextiles. Such materials can be fabricated by different techniques, such as spunbonding, melt blown, carded thermal bonding and carded chemical bonding, dry and/or wet laid and needlefelts. Because of the nature of such applications the market is increasingly demanding products with specific properties such as antimicrobial efficacy. Efforts have been made in incorporating antimicrobial active agents in binders which sometimes are used to make nonwovens in processes like carded chemical bonding, dry and wet laid.
Amongst various nonwoven products, materials made by spunbonding and melt blown techniques have some unique properties and are becoming more and more important because of advantages in manufacturing as well as in product properties. Spunbond nonwovens can be made directly from thermoplastic polymers such as polypropylene, polyethylene, polyester and nylon. This process offers lower manufacturing cost, improved processability and performance in the final product such as coverstock for disposable baby diapers, feminine hygiene and adult incontinence. Spunbond nonwovens can also be used as durable products such as geotextiles and roof membranes. Characterised by a large surface area and small pore size, melt blown nonwovens differ from traditional spunbonds in their lower fibre denier and fineness. But similarly, melt blown nonwovens are also manufactured by directly extruding thermoplastic polymers, especially high melt flow polypropylene. Their applications include filtration, feminine hygiene, wipers, face masks and absorbents.
Selected antimicrobial substances can be incorporated into the polymer melt before the extrusion. This method enables the antimicrobials to be built into the nonwovens and to migrate onto the surface. Long lasting antimicrobial efficacy of such type of materials is achieved by the continues migration of the active ingredient to the surface. The disadvantage of such type of incorporation is that the processing temperature for manufacturing melt blown and spunbond nonwovens is usually very high, i.e., up to 300° C. At such temperature, the involved antimicrobials, especially organic based antimicrobials can cause problems in volatility as well as thermostability.
It is therefore desirable to find an alternative process in which antimicrobials, preferably organic based antimicrobials, are incorporated in nonwoven materials, preferably those made by spunbond and melt blown processes, without undergoing a high temperature process.
Surprisingly, it was found that this object can be achieved in treating an already-formed nonwoven with a formulation comprising
(a) an antimicrobial agent selected from
(a
1
) halogeno-o-hydroxydiphenyl compound;
(a
2
) phenol derivative;
(a
3
) benzyl compound;
(a
4
) chlorohexidine and a derivative thereof;
(a
5
) C
12
-C
14
alkylbetaine and C8-C
18
fatty acid amidoalkylbetaine;
(a
6
) an amphoteric surfactant;
(a
7
) trihalocarbanilide;
(a
8
) quaternary and polyquaternary compound; and
(a
9
) a thiazole compound; and
(a
10
) a iodine containing agent;
(a
11
) a naphthyl derivative;
(b) a solubilizing agent; and optionally
(c) at least one copolymer made from two or more monomers, with at least one monomer having good affinity to the textiles and at least another monomer having affinity to the involved antimicrobial substances.
The nonwovens used for the process of the present invention are preferably prepared by spun bond and melt blown processes or by carded chemical bonding, carded thermal bonding, dry and/or wet laid and needlefelts.
Preferably, the antimicrobial agent (a
1
) is selected from compounds of the formula
wherein
X is oxygen, sulfur or —CH
2
—,
Y is chloro or bromo,
Z is SO
2
H, NO
2
or C
1
-C
4
-Alkyl,
r is 0 to 3,
o is 0 to 3,
p is 0 or 1,
m is 0 or 1 and
n is 0 or 1;
and at least one of r or o is ≠0.
Preferably, in the present process, antimicrobial agents (a
1
) of formula (1) are used, wherein
X is oxygen, sulfur or —CH
2
—, and
Y is chloro or bromo,
m is 0,
n is 0 or 1,
o is 1 or 2,
r is 1 to 3 and
p is 0.
Of particular interest as antimicrobial agent (a
1
) is a compound of formula
wherein
X is —O— or —CH
2
—;
r is 1 to 3; and
o is 1 or 2, and most preferably a compound of formula
Preferred phenol derivatives (a
2
) correspond to formula
wherein
R
1
is hydrogen, hydroxy, C
1
-C
4
alkyl, chloro, nitro, phenyl or benzyl,
R
2
is hydrogen, hydroxy, C
1
-C
6
alkyl or halogen,
R
3
is hydrogen, C
1
-C
6
alkyl, hydroxy, chloro, nitro or a sulfo group in the form of the alkali metal salts or ammonium salts thereof,
R
4
is hydrogen or methyl,
R
5
is hydrogen or nitro; and
R
6
is hydrogen; or a radical of formula (4a)
Such compounds are typically chlorophenols (o-, m-, p-chlorophenols), 2,4-dichlorophenol, p-nitrophenol, picric acid, xylenol, p-chloro-m-xylenol, cresols (o-, m-, p-cresols), p-chloro-m-cresol, pyrocatechin, resorcinol, orcinol, 4-n-hexylresorcinol, pyrogallol, phloroglucine, carvacrol, thymol, p-chlorothymol, o-phenylphenol, o-benzylphenol, p-chloro-o-benzylphenol and 4-phenolsulfonic acid.
Typical antimicrobial agents (a
3
) correspond to the formula
wherein
R
1
, R
2
, R
3
, R
4
, R
5
are each independently of one another hydrogen or chloro; and
R
6
is —OH; or —O—(CO)—C
6
H
5
.
Illustrative examples of compounds of formula (5) are benzyl alcohol, 2,4-, 3,5- or 2,6-dichlorobenzyl alcohol and trichlorobenzyl alcohol.
Antimicrobial agent (a
4
) is chlorhexidine and salts thereof, for example 1,1′-hexamethylene-bis-(5-(p-chlorophenyl)-biguanide), together with organic and inorganic acids and chlorhexidine derivatives such as their diacetate, digluconate or dihydrochloride compounds.
Antimicrobial agent (a
5
) is typically C
8
-C
8
cocamidopropylbetaine.
Amphoteric surfactants as antimicrobial agents (a
6
) are suitably C
12
alkylaminocarboxylic and C
1
-C
3
alkanecarboxylic acids such as alkylaminoacetates or alkylaminopropionates.
Typical trihalocarbanilides which are useful as antimicrobial agent (a
7
) are compounds of the formula
wherein
Hal is chloro or bromo,
n and m are 1 or 2, and
n+m are 3.
The quaternary and polyquaternary compounds which correspond to antimicrobial agent (a
8
) are of the formula
wherein
R
6
, R
7
, R
8
and R
9
are each independently of one another C
1
-C
18
alkyl, C
1
-C
18
alkoxy or phenyl-lower alkyl, and
Hal is chloro or bromo.
Among these salts, the compound of formula
wherein
n is an integer from 7 to 17, is very particularly preferred.
A further exemplified compound is cetyl trimethylethyl ammonium bromide.
Of particular interest as antimicrobial agent (a
9
) is methylchloroisothiazoline.
Iodine containing agents (a
10
) are for example iodopropyl butyl carbamate.
Preffered antimicrobial agent (a
11
) is the compound of formula
The antimicrobial agents which are used in the present process are water-soluble or only sparingly soluble in water. In the present aqueous formulation they may therefore be applied in solubilized, emulsified or dispersed form.
The present aqueous formulation therefore additionally comprises a small amount of an organic solvent, a surfactant, a dispersant, and/or an emulsifier as component (b). This component is useful for solubilization and stabilization of the antimicrobial agents in the present aqueous formulation.
Suitable solubilizing agents are anionic, nonionic or zwitterioni
Ciba Specialty Chemicals Corporation
Gupta Yogendra N.
Mansfield Kevin T.
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