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Topic: Isocyanate


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In the News (Sun 21 Apr 19)

  
  ATSDR - ToxFAQs™: Methyl Isocyanate
Methyl isocyanate is a colorless highly flammable liquid that evaporates quickly when exposed to the air.
Methyl isocyanate gas is degraded rapidly in the air by reacting with substances commonly found in the air.
Methyl isocyanate has been found in the smoke from tobacco, so people who smoke or breathe second-hand smoke may be exposed to this compound.
www.atsdr.cdc.gov /tfacts182.html   (1054 words)

  
  Methyl isocyanate - Wikipedia, the free encyclopedia
A detectable odor of methyl isocyanate is a concentration triple the permissible exposure.
The toxic effect of the compound was apparent in the accidental release of around 40,000 kilograms of methyl isocyanate over Bhopal, India on December 3, 1984.
It was discovered in 1888 as an ester of isocyanic acid.
en.wikipedia.org /wiki/Methyl_isocyanate   (187 words)

  
 United States Patent Application: 0020153507
The isocyanate prepolymer composition of claim 1, wherein said phosphate ester is present in an amount of from 0.1 to 1.2 weight percent based on the total weight of the prepolymer composition.
With more particularity, the invention pertains to isocyanates and isocyanate pre-polymers and the use of esters of phosphoric acid to restrict the reaction of the isocyanate with ambient water in the air and thereby extend the time period in which the isocyanate or isocyanate pre-polymer may be used in a processing operation.
The isocyanate prepolymer composition is formed from the reaction of a polyhydroxyl compound and an excess of an isocyanate compound.
appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=20020153507.PGNR.&OS=DN/20020153507&RS=DN/20020153507   (4439 words)

  
 Isocyanate -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-23)
An isocyanate is a ((chemistry) a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight) compound containing the isocyanate group.
Examples of isocyanate compounds used in the (A naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers) polymer industry are isomers of toluene diisocyanate (TDI), methylene diphenyl 4,4'-diisocyanate (MDI), and hexamethylene diisocyanate (HDI).
Isocyanates such as these can (Click link for more info and facts about react) react with an (A liquor or brew containing alcohol as the active agent) alcohol to produce a (An ester of carbamic acid) urethane linkage.
www.absoluteastronomy.com /encyclopedia/i/is/isocyanate.htm   (267 words)

  
 Spraying Isocyanate Paints and Primers - Formatted for Print
Isocyanates are highly reactive chemicals typically found in the hardener of two-part paints and primers.
All spraying of isocyanate paints must be done in a commercial or engineered paint booth, or one that is acceptable to the local fire authority.
There is not enough unreacted isocyanate released during mixing to require the wearing of air-supplied respirators; however, a face shield should be worn where there is a risk of splashing paint into the eyes.
www.labour.gov.sk.ca /safety/isocynates/printpage.htm   (853 words)

  
 IsoCyanate 2000
The analytical chemistry of airborne isocyanates, which initially focused on colorimetric techniques, has matured with the introduction of various secondary amine reagents coupled with collection and chromatographic determination of the resulting urea derivatives.
Case reports in the medical literature have suggested that occupational asthma may be induced by exposure to oligomeric and pre-polymeric isocyanates and other forms of TRIG in the absence of sensitization to the parent diisocyanate monomer.
Isocyanate in the vapor phase diffuses to the walls of the denuder during transit and is collected while the respirable fraction of the aerosol phase exiting the inlet pre-separator penetrates past the denuder to be collected by the back-up filter.
www.anchem.su.se /isocyanate2000/abstracts/abs_rando.html   (856 words)

  
 ATSDR - MMG: Methyl Isocyanate
Significant exposure to methyl isocyanate vapors would most likely be the result of accidental release of methyl isocyanate to the air such as occurred in Bhopal, India in 1984, where the primary effect was pulmonary edema with some alveolar wall destruction.
Methyl isocyanate is incompatible with oxidizers, acids, alkalis, amines, iron, tin, and copper.
Methyl isocyanate vapors are severely irritating and corrosive to the respiratory tract.
www.atsdr.cdc.gov /MHMI/mmg182.html   (4862 words)

  
 Silicone and ionically modified isocyanate adduct - US Patent 6641922   (Site not responding. Last check: 2007-10-23)
Reaction-product comprising an isocyanate adduct of a composition comprising in admixture:
Isocyanate terminated prepolymers can also be used as well as mixtures of isocyanates with average fractional values of isocyanate functionality.
In the first stage of the reaction, an isocyanate terminated compound is formed by reacting the silicone containing compound and a potential ion-containing monomer with a stoichiometric excess of a polyisocyanate.
www.patentstorm.us /patents/6641922.html   (6403 words)

  
 EPA - Air Toxics Website - Methyl Isocyanate
Methyl isocyanate is used to produce carbamate pesticides.
Methyl isocyanate is extremely toxic to humans from acute (short-term) exposure.
Acute animal tests in rats have shown methyl isocyanate to have extreme acute toxicity from inhalation exposure and high acute toxicity from oral exposure.
www.epa.gov /ttn/atw/hlthef/methylis.html   (1201 words)

  
 United States Patent Application: 0020193625
The process of claim 1 in which the isocyanate in the isocyanate formulation is toluene diisocyanate.
The process of claim 1 in which the isocyanate in the isocyanate formulation is hexamethylene diisocyanate.
The isocyanate formulation of claim 8 in which the diisocyanate or polyisocyanate a) is toluene diisocyanate.
appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=20020193625.PGNR.&OS=DN/20020193625&RS=DN/20020193625   (1727 words)

  
 CHEST: Need for monitoring nonspecific bronchial hyperresponsiveness before and after isocyanate inhalation challenge - ...   (Site not responding. Last check: 2007-10-23)
Isocyanate concentration was continuously measured with a MDA monitor (model 7100; MDA Scientifc; Greenview, IL).
In the 14 patients in whom P[C.sub.20] was monitored after the first isocyanate SIC, it varied from negative to positive in three patients and, in the remaining patients, it showed a reduction that ranged from 0.6-fold to 15.2-fold (mean, fourfold).
The proportion of positive SIC results with isocyanates in our series (16 of 22 tests, 73%) is similar to that of previous studies in patients with suspected isocyanate asthma.
www.findarticles.com /p/articles/mi_m0984/is_4_123/ai_100807285   (1342 words)

  
 Isocyanates Adhesion and Bonding Techniques
Isocyanates are used in combination with other polymers to enhance adhesion to textile fibers.
Isocyanates are particularly recommended for use with polyester fibers because of certain principals in adhesion science.
Isocyanate adhesives, like those used in the textile treating industry, are generally made by the user because of their very short, 1-3 day, shelf life.
www.warwickmills.com /Isocyanates.html   (553 words)

  
 CDC | Case Definition: Methyl Isocyanate Poisoning
Exposure to methyl isocyanate typically occurs through inhalation or dermal absorption.
Environmental: Detection of methyl isocyanate in environmental samples, as determined by NIOSH.
Suspected: A case in which a potentially exposed person is being evaluated by health-care workers or public health officials for poisoning by a particular chemical agent, but no specific credible threat exists.
www.bt.cdc.gov /agent/methylisocyanate/casedef.asp   (335 words)

  
 Latent catalysts for the isocyanate polyaddition reaction - Patent 4521545
The present invention relates to ammonium salts of the type obtained by reacting mono- or polyfunctional, primary, secondary and/or tertiary amines with alkylating esters of acids of phosphorus, preferably in an equivalent ratio of alkylating acids of phosphorus to primary, secondary and/or tertiary amine nitrogen atoms of 1:1.
The ammonium salts useful in the present invention may be obtained by reacting (i) mono- or polyfunctional, primary, secondary and/or tertiary amines with (ii) alkylating esters of acids of phosphorus.
To systematically study the ammonium salts as latent catalysts for the isocyanate polyaddition reaction, 0.2 g of each of ammonium salts I, II, V and VI was added to quantities of 50 g of a polyether polyol (OH number 380) produced by the propoxylation of trimethylol propane.
www.freepatentsonline.com /4521545.html   (3809 words)

  
 Use of isocyanates containing urethane groups as drying agents and a process for the production of a coating ...
The isocyanates or isocyanate mixtures to be used in accordance with the invention are prepared by known methods, e.g., by reacting excess diisocyanate with the OH components at about 80.degree.
By using an excess of the isocyanate component over the water to be removed from the auxiliaries and additives, free isocyanate groups are left over and, together with the one-component binder, react with atmospheric moisture after formation of the coating to form a uniform coating with no defects.
In general, the ratio by weight of the isocyanate component used for drying in accordance with the process of the invention and the one-component binder is 1:1 to 1:40, preferably 1:2 to 1:10.
www.freepatentsonline.com /5179187.html   (4009 words)

  
 World Intellectual Property Organization   (Site not responding. Last check: 2007-10-23)
Reaction of the mono-hydroxy functional monol with the isocyanate terminated intermediate is monitored by isocyanate absorbance band by using a Fourier transform infrared spectrometer and isocyanate titration.
Although, in principle, it is intended that all of the isocyanate functionality of the polyisocyanate be reacted, it should be understood that 100 percent complete reaction cannot always be attained, and therefore, trace amounts of unreacted isocyanate and/or unreacted hydroxyls can be expected.
Alternatively, reacting"all"of the isocyanate for the purposes of the present invention may be defined as at least 99 percent complete reaction, preferably 100 percent.
www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/53373.010726&ELEMENT_SET=DECL   (3786 words)

  
 Features Item : Combinations of Malonate- and Pyrazole-Blocked Isocyanates to Improve Performance   (Site not responding. Last check: 2007-10-23)
Blocked isocyanates have been available for many years to produce room-temperature stable, one pack (1K), heat-curable coatings.1 As in all aspects of coating formulation, there is increasing demand for improved quality without increasing formulation costs.
This improved behavior is due to the incorporation of hybrid-blocked isocyanate, where a proportion of the trimer molecules are blocked with both DEM and DMP (as well as a proportion, which are blocked with either DEM or DMP).
For a hybrid DEM/DMP-blocked isocyanate with a 1:1 ratio of DEM/DMP the optimum ratio of OH:NCO is therefore 1.3:1.
www.pcimag.com /CDA/ArticleInformation/features/BNP__Features__Item/0,1846,85279,00.html   (1732 words)

  
 [No title]
The major route of occupational exposure to isocyanates is inhalation of the vapor or aerosol; exposure may also occur through skin contact during the handling of liquid isocyanates.
When there is potential for isocyanate exposure, workers should be provided with and required to use appropriate personal protective clothing and equipment such as coveralls, footwear, chemical-resistant gloves and goggles, full faceshields, and suitable respiratory equipment.
Isocyanate exposure and hypersensitivity pneumonitis--report of a probable case and prevalence of specific immunoglobulin G antibodies among exposed individuals.
www.cdc.gov /niosh/asthma.html   (3730 words)

  
 Aromatic Isocyanate Surface Contamination Sampling and Evaluation Techniques   (Site not responding. Last check: 2007-10-23)
The 1-(2-pyridyl) piperazine is a derivatizing agent that stabilizes the isocyanate.
For example, a negative result (no color change) of the Permea-Tec®, after being worn under a glove for a time period, in a work environment known to have contaminants present, demonstrates that the glove protection was effective for that time period, in those working conditions.
It is a reliable indicator to a detection limit of 3-5 µg aromatic isocyanates.
www.osha-slc.gov /SLTC/isocyanates/mrl_inte.html   (1401 words)

  
 Guidance Note: Controlling Isocyanate Hazards At Work   (Site not responding. Last check: 2007-10-23)
Isocyanates are a group of chemicals used in the manufacture of polyurethane plastics, synthetic rubbers, foams, paints, varnishes and adhesives.
People exposed to isocyanates at work are at greater risk of developing respiratory problems, such as asthma, if they breathe in isocyanate vapours or droplets of resin spray.
Isocyanates and other chemicals classed as dangerous goods must be stored in accordance with the Storage of Dangerous Goods Regulations administered by the Department of Minerals and Energy.
www.safetyline.wa.gov.au /PageBin/guidwswa0063.htm   (1746 words)

  
 Isocyanate paints in motor vehicle repair shops moves up fr...
Isocyanates are the number one cause of occupational asthma.
Vapours, spray mists and dusts containing isocyanates are highly irritant to the respiratory tract and eyes, and may bring about or worsen existing asthma, or cause dermatitis.
Free Copies of Safety in motor vehicle repair: Working with 2-pack isocyanate paints (INDG 388) can be ordered free of charge online at http://www.hsebooks.com or are available from HSE Books, PO Box 1999, Sudbury, Suffolk, CO10 2WA, tel: 01787-881165 or fax: 01787-313995.
www.hse.gov.uk /press/2003/e03203.htm   (590 words)

  
 Brian Jones and Associates - Polyurethane Chemistry & Calculations   (Site not responding. Last check: 2007-10-23)
Three moles of isocyanate can react to form the 6 membered isocyanurate ring structure, this is the most common reaction where there is a significant excess of free isocyanate.
The blocked isocyanate, which can be a diisocyanate, a quasi-prepolymer or a prepolymer, can then be handled and processed without concern for further reaction/gelation, since no unreacted isocyanate remains.
Both aromatic and aliphatic isocyanates are commercially available, aromatic isocyanates are faster reacting by a factor of between 2 -10 depending on their chemical structure.
www.brian-jones.co.uk /puchem.shtml   (1973 words)

  
 ISOCHEK® Isocyanate Method
Immediately after sampling, the teflon filter is placed in a solution to derivatize any isocyanate collected as aerosol or particulate.
Due to sampling efficiency, reactivity, and stability considerations, different derivatives are used for the vapour and aerosol fractions, and thus analysis is performed by HPLC under different conditions.
As this limitation does not affect vapour-phase isocyanates which form a derivative immediately during the sampling, if only vapour is being sampled the collection time may be extended.
www.fhs.mcmaster.ca /oehl/isochek.html   (501 words)

  
 Aliphatic isocyanate compounds - Patent 4619999
Polyfunctional isocyanates have been found useful in a number of applications, including for example their use as components in polyurethane coating formulations, in reaction injection molding (RIM) applications and as cross-linking agents.
The reaction between isocyanic acid and the N-alkoxymethyl compound may suitably be carried out in a solvent medium, e.g., toluene, and in the presence of a strong acid catalyst such as n-dodecylbenzene sulfonic acid.
The aliphatic isocyanate compounds of the invention may be employed to form a cross-linkably curing composition comprising the aliphatic isocyanate compound and a polymer containing a functionality which may be --OH, --COOH, --CONH.sub.2, --NH.sub.2 and --SH.
www.freepatentsonline.com /4619999.html   (933 words)

  
 Stable isocyanate formulations - US Patent 6433218   (Site not responding. Last check: 2007-10-23)
Prepolymers having at least two terminal isocyanate groups useful in the practice of the present invention may be prepared by any of the techniques known to those in the art.
After the chain extender has been added to the isocyanate, however, it is preferred that the isocyanate formulation be maintained at a temperature of at least 50° C. In some cases, it is advantageous to agitate or stir the isocyanate formulation at regular intervals.
The isocyanate formulations of the present invention may be reacted with any of the isocyanate-reactive materials known to those in the art.
www.patentstorm.us /patents/6433218.html   (1974 words)

  
 World Intellectual Property Organization   (Site not responding. Last check: 2007-10-23)
One aspect of the invention is directed to an adhesive composition comprising a blend of a polyurethane hot melt and a polymeric isocyanate.
isocyanates which may be used in the practice of the invention are aromatic or aliphatic, more preferable aromatic isocyanate oligomers having 2 or more, preferably 2-10 repeating units, which have an isocyanate functionality of 2 or more, preferably between about 2 and about 3.
The adhesive of claim 1 wherein the polyurethane hot melt comprises a monomeric isocyanate, a polymeric isocyanate or a mixture thereof.
www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=03/06569.030123&ELEMENT_SET=DECL   (3636 words)

  
 Isocyanate-Wood Adhesive Bond   (Site not responding. Last check: 2007-10-23)
In the latterinstance, we have investigated oven-dried wood, wood at its fibersaturation point, and wood at 19% and 7% moisture levels.
Our resultsshow that the isocyanate reacts with all these entities, but that itsreaction with water is quicker than with any of the other hydroxylcontaining compounds, and when water is present the water-isocyanatereaction dominates all others.
For wood at higher moisture content levels, ourinfrared results suggest that the isocyanate reacts with the water inpreference to the wood polymers.
www.s-a-s.org /journal/95/asv49n2/ASv49n2_sp4.html   (187 words)

  
 Polyurethanes — What Goes Into PUs?
The modified isocyanates and isocyanate pre-polymers with special reactivity characteristics are used when it is impractical to use the more conventional isocyanates.
In a pre polymer system, the polyol and isocyanate (either a polyester or a polyether) are reacted to give a pre polymer that may be either a liquid or a waxy solid.
The chain-extender reacts with the isocyanate to affect the hard/soft segment relationship and therefore the modulus and glass transition temperature (Tg) of the polymer.
www.azom.com /details.asp?ArticleID=218   (1625 words)

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