Bleaching and dyeing; fluid treatment and chemical modification – Chemical modification of textiles or fibers or products thereof – Cellulose fibers
Reexamination Certificate
1999-10-08
2001-06-05
Liott, Caroline D. (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Chemical modification of textiles or fibers or products thereof
Cellulose fibers
C008S115510, C008S115700, C008S190000, C008S115580, C008S115590, C008S115690
Reexamination Certificate
active
06241783
ABSTRACT:
FIELD OF THE INVENTION
In general, this invention relates to methods for generating biocidal materials and improved methods for producing them. In particular, this invention provides improved processes for producing biocidal materials in the absence of toxic materials.
BACKGROUND OF THE INVENTION
Studies indicate that formaldehyde is a potential human carcinogen. Airborne concentrations above 0.1 ppm can cause irritation of the eyes, nose and throat. The severity of irritation increases as concentrations increase; at 100 ppm it is immediately dangerous to life and health. Facilities that manufacture, consume or produce formaldehyde must control workers exposure in accordance with strict regulations. Dermal contact causes various skin reactions including sensitization, which could force persons thus sensitized to find other work.
The permissible exposure limit (PEL) for formaldehyde in all workplaces (including general industry, construction, and maritime, but not in agriculture) covered by the Occupational Safety and Health Act is 0.75 ppm measured as an 8-hour time weighted average (TWA). This standard includes a 2 ppm short-term exposure limit (STEL) (ie., maximum exposure allowed during a 15-minute period). The “action level” is 0.5 ppm measured over 8 hours.
U.S. Pat. No. 5,882,357, which issued to Sun et al., on Mar. 16, 1999, discloses the use of heterocyclic amines such as 1,3-dimethylol-5,5-dimethylhydantoin (DMDMH) and monomethylol-5,5-dimethylhydantoin (MDMH), to impart durable and regenerable antimicrobial functions to inter alia, cellulose materials. In certain instances, during the process of imparting antimicrobial properties to cellulosic materials, free-formaldehyde can be generated. Moreover, when these microbiocidal textiles are stored under humid conditions, free-formaldehyde can be released.
Thus, despite the advances made by U.S. Pat. No. 5,882,357, there remains a need to reduce the amount of formaldehyde released during preparation of microbiocidal products. The present invention remedies such need by providing processes that reduce the amount of formaldehyde during the preparation of microbiocidal articles.
SUMMARY OF THE INVENTION
Formaldehyde causes eye, upper respiratory tract and skin irritation and is a skin sensitizer. Sensory irritation occurs at concentrations as low as 0.1 ppm and significant irritation of the nose and throat occurs at concentration of about 1 ppm. Moreover, dermal contact causes various skin reactions, thus forcing persons sensitized to find other work. In certain instances, a byproduct of producing antimicrobial articles is the presence of free-formaldehyde. To remedy this drawback, the present invention provides a process for preparing a microbiocidal article with a reduction in free-formaldehyde release, the process comprising: (a) immersing the article in an aqueous treating solution which comprises a heterocyclic amine and a polyol; and (b) treating the article with a halogenated solution, thereby rendering the article microbiocidal with a reduction in free-formaldehyde release. Preferably, the aqueous treating solution further comprises a catalyst and a wetting agent.
In certain preferred aspects, formaldehyde is scavenged by a polyol that reduces the formaldehyde to a harmless product. The preferred polyols include, but are not limited to, diethylene glycol or ethylene glycol. In certain preferred embodiments, the heterocyclic amine is alkylated or partially alkylated. Suitable heterocyclic amines for use in the present invention include, but are not limited to, DMDMH, alkylated DMDMI, or a mixture of DMDMH and its unmethylolated dimethylhydantoin (DMH) derivative. Using the aforementioned heterocyclic amines, it is possible to produce microbiocidal articles with low potential for formaldehyde release.
In another aspect, the present invention provides a process for preparing a microbiocidal article with a reduction in free-formaldehyde release, the process comprising: (a) immersing the article in an aqueous treating solution which comprises an alkylated heterocyclic amine; and (b) treating the article with a halogenated solution, hereby rendering the article microbiocidal with a reduction in free-formaldehyde release. In this aspect, the alkylated or partially alkylated heterocyclic amine is less amenable to releasing formaldehyde than a heterocyclic amine. Optionally, a polyol is used in conjunction with an alkylated heterocyclic amine to reduce formaldehyde. Moreover, a catalyst and a wetting agent can optionally be used in the aqueous treating solution.
These and other aspects of the present invention will be readily apparent when read with the detailed description and figures that follow.
DEFINITIONS
As used herein, the acronym “DMDMIH” refers to 1,3-dimethylol-5,5-dimethylhydantoin.
As used herein, the acronym “MDMH” refers to monomethylol-5,5-dimethylhydantoin.
As used herein, the acronym “DMDHEU” refers to dimethyloldihydroxy-ethylene urea.
As used herein, the acronym “DMH” refers to dimethyloldihydroxy-ethylene urea.
The term “alkylated” or “partially alkylated” refers to adding alkyl functional groups containing about 1 to 6 carbon atoms to heterocyclic amines having a free hydroxy group (e.g., hemiacetal functionality). These alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, n-pentyl and the like. Partially alkylated means adding alkyl functional groups, but still leaving at least one free hydroxy group (e.g., hemiacetal functionality). In preferred embodiments, DMDMH and MDMH are alkylated or partially alkylated.
REFERENCES:
patent: 2950553 (1960-08-01), Hurwitz
patent: 3061469 (1962-10-01), Manowitz et al.
patent: 3260565 (1966-07-01), Beachem
patent: 3401005 (1968-09-01), Katz
patent: 3445279 (1969-05-01), Abrahams et al.
patent: 3488701 (1970-01-01), Herbes et al.
patent: 3565824 (1971-02-01), Pierce, Jr. et al.
patent: 3576591 (1971-04-01), Cusano
patent: 3594113 (1971-07-01), Lifland et al.
patent: 3650667 (1972-03-01), Luechauer
patent: 3674811 (1972-07-01), Kern
patent: 3812201 (1974-05-01), Bey
patent: 4199322 (1980-04-01), Danna et al.
patent: 4284758 (1981-08-01), North
patent: 4300898 (1981-11-01), North
patent: 4306872 (1981-12-01), Herbes et al.
patent: 4396391 (1983-08-01), North
patent: 4585650 (1986-04-01), Newberry, Jr. et al.
patent: 4844891 (1989-07-01), Rosen et al.
patent: 5104649 (1992-04-01), Jansson et al.
patent: 5208016 (1993-05-01), Ohmae et al.
patent: 5221574 (1993-06-01), Branch et al.
patent: 5352693 (1994-10-01), Farina
patent: 5405862 (1995-04-01), Farina et al.
patent: 5490983 (1996-02-01), Worley et al.
patent: 5610189 (1997-03-01), Whiteley
patent: 5707404 (1998-01-01), Andrews et al.
patent: 2500430 (1975-07-01), None
patent: 4125431 (1992-07-01), None
patent: 2161399 (1986-01-01), None
Chemical Abstracts, 78(12), p. 66, col. 1, No. 73517u, Mar. 26, 1973.
Gagliardi, et al., “Antibacterial finishes,”American Dye-stuff Reporter, 2:31-40, Jan. 1962.
Rigby, et al., “Medical textiles—Textile materials in medicine and surgery,”Textile Horizons, pp. 42-45 (1993) (month unknown/unavailable).
Sun, et al., “A new cyclic n-halamine biocidal polymer,”Ind. Eng. Chem. Res., 33:168-170 (1994) (month unknown/unavailable).
Vigo, “Antimicrobial fibers and polymers,”Manmade Fibers: Their Origin and Development, pp. 214-226 (1992) (month unknown/unavailable).
Vigo, “Advances in microbial polymers and materials,”Biotechnology and Bioactive Polymers, Edited by Gebelein and Carraher, Plenum Press, New York, pp. 225-237 (1994) (month unknown/unavailable).
Worley, et al., “Biocidal polymers,”Trends in Polymer Science, 4(11):364-370 (1996) (month unknown/unavailable).
Liott Caroline D.
The Regents of the University of California
Townsend & Townsend & Crew LLP
LandOfFree
Formaldehyde scavenging in microbiocidal articles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Formaldehyde scavenging in microbiocidal articles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Formaldehyde scavenging in microbiocidal articles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2464063