• Title, Summary, Keyword: isocyanate

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Synthesis and PSA Properties of Acryl Modified Resin for Semiconductor Wafer (반도체 웨이퍼용 아크릴 변성 수지의 합성 및 점착 특성)

  • Sim, Jong Bae;Shin, Kyoung Sub;Hwang, Taek Sung
    • Journal of Adhesion and Interface
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    • v.11 no.2
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    • pp.63-69
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    • 2010
  • In this study, acryl resin PSA containing hydroxyl group based on 2-EHA (2-ethyl hexyl acrylate), 2-EHMA (2-ethyl hexyl methacrylate), 2-HEA (2-Hydroxy ethyl acrylate), acrylic acid was synthesized and then, isocyanate modified acryl resin PSA prepared with adduct reaction according to the amount of MOI (Methacryloyloxyethyl isocyanate) or 2-isocyanatoethyl methacrylate that can improve the curing property. This research shows that the initial PSA and peel adhesion are decreased according to the increase of the amount of the MOI and isocyanate curing agent. After UV irradiating, the peel adhesion is decreased with increasing the amount of the MOI (Methacryloyloxyethyl isocyanate) and isocyanate curing agent, because of the high curing property.

Methyl Isocyanate and Carcinogenesis: Bridgeable Gaps in Scientific Knowledge

  • Senthilkumar, Chinnu Sugavanam;Sah, Nand Kishore;Ganesh, Narayanan
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2429-2435
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    • 2012
  • Methyl isocyanate may have a role in cancer etiology, although the link is unclear. There is evidence in the literature that it can induce cancer in animals but the carcinogenic potency is weak. Pheochromocytoma of adrenal medulla and acinar cell tumors of pancreas have been observed in methyl isocyanate exposed animals. Conversely, emerging data from population-based epidemiological studies are contradictory since there is no evidence of such cancers in methyl isocyanate exposed humans. Recently, we reported a high prevalence of breast and lung cancers in such a population in Bhopal. In vitro findings appearing in the latest scientific literature suggest that genomic instability is caused by methyl isocyanate analogs in lung, colon, kidney, ovary epithelial cells, and that hepatocytes may undergo oncogenic transformation, have obvious implications. The conflicting information prompted us to present this update over the last three decades on methyl isocyanate-induced cancers after an extensive literature search using PubMed. While the pertinent literature remains limited, with a scarcity of strong laboratory analyses and field-epidemiological investigations, our succinct review of animal and human epidemiological data including in vitro evidences, should hopefully provide more insight to researchers, toxicologists, and public health professionals concerned with validation of the carcinogenicity of methyl isocyanate in humans.

Preparation of Sodiumisocyanate and its Analyzing Method in the Presence of Impurities $Na_2CO_3$, Urea, and Biuret (Sodium Isocyanate의 제법 및 $Na_2CO_3$, Urea, Biuret 혼재시 그의 정량분석법에 관한 연구)

  • 국채호
    • YAKHAK HOEJI
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    • v.7 no.2_3
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    • pp.67-71
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    • 1963
  • Studies the reaction mechanism and optimal reaction condition of the process of preparing sodium isocyanate, by means of heating of sodium carbonate and urea. Proposing, at the sametime, the quantitative analyzing method of sodium isocyanate in the presence of impurities of $Na_{2}CO_{3}$, urea and biuret. 1. Sodium isocyanate could be prepared by means of heating reaction of sodium carbonate and urea. 2. Adding urea into the heated sodium carbonate is reasonable. 3. Quantitative analysis of sodium isocyanate in the presence of impurities, $Na_{2}CO_{3}$, urea and biuret could be done by the following method:-adding nitrobarite solution into sample solution in order to remove $CO_{3}"$ and neutralize the solution, filtering off $BaCO_{3}$, and then precipitating isocyanate as a silver salt, filtering off AgNCO, and then, titrating remaining $AgNO_{3}$ with $NH_{4}SCN$, (indicator $FeNH_{4}(SO_{4})_{2})$/TEX>

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Development of a New Method for Total Isocyanate Determination Using the Reagent 9-Anthracenylmethyl 1-Piperazinecarboxylate(PAC):Part 1 - The reaction condition and stability (9-Anthracenylmethyl 1-Piperazinecarboxylate(PAC)을 이용한 공기중 총이소시아네이트 분석방법 개발:제1부 반응조건 및 안전성)

  • Roh, Young-Man;Streicher, Robert P.
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.9 no.2
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    • pp.167-176
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    • 1999
  • A new analytical procedure for the measurement of monomeric isocyanates and total isocyanate group in workplaces has been investigated. The method described herd involves derivatization of the isocyanate sample upon collection with the reagent 9-anthracenylmethyl 1-piperazinecarboxylate (PAC). Laboratory investigations have demonstrated that excess PAC reagent can be satisfactorily removed from PAC-derivatized monomeric isocyanates-a requirement for the success f the analytical procedure. After removal of excess PAC reagent, the PAC derivatives of butyl isocyanate, phenyl isocyanate, HDI, MDI, and TDI were reacted with sodium thiomethoxide to convert them all to 9-anthracenylmethyl methyl sulfide (AMMS). Total isocyanate group was determined by HPLC analysis and quantification of the single AMMS peak. This circumvents many of the disadvantages associated with current HPLC methods. There were no longer problems associated with quantifying late-eluting peaks and analysis times were very short. A single detector was used for quantification because a standard of the analyte existed and the retention time could be determined. Because all species were converted to a single analyte, the problem of variability of response factors among different species was averted. Finally, there were no complex chromatograms to interpret. Monomers of other individual species were measured by analysis of the sample before the individual species were converted to AMMS. The favorable performance of PAC warrants its further study as a reagent for the determination of total isocyanate group in air.

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A Case of Hypersensitivity Pneumonitis in an Automobile Paint Sprayer (자동차 페인트 도장공에서 발생한 과민성 폐렴 1예)

  • Oh, Mi Na;Cho, Myoung Jin;Baek, Hoon Ki;Cho, Ki Sung;Kang, Ji Hoon;Kim, Young;Kwak, Jin Young
    • Tuberculosis and Respiratory Diseases
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    • v.65 no.6
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    • pp.541-545
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    • 2008
  • Hypersensitivity pneumonitis (HP) is an immunologically-mediated disease resulting from repeated exposure to sensitizing agents, such as organic dusts or chemicals. Isocyanate is a volatile and highly reactive chemical that is extensively used in the manufacturing of automobiles, upholstery, and polyurethane foam. Occupational respiratory diseases associated with isocyanate, such as bronchial asthma, are well-known. It is thought that HP is one of the rare diseases induced by isocyanate with a very low frequency worldwide. We report a case of HP in an automobile painting sprayer which appeared to be associated with isocyanate.

Properties of Silk-Sericin Films Modified by Isocyanate Compounds (화학 개질된 실크세리신 필름의 특성)

  • Yoon, Heung-Soo;Takahashi, Kiyohisa
    • Textile Coloration and Finishing
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    • v.20 no.2
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    • pp.29-37
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    • 2008
  • Polar amino groups of the waste SS(silk-sericin) were modified by two isocyanate compounds of MOI[2-(methacryloyloxy)ethyl isocyanate] and AOI [2-(acryloyloxy)ethyl isocyanate]. When the MOISS (MOI-modified silk sericin) or AOISS(AOI-modified silk sericin) was pressed hot, vinyl groups in the MOI or AOI were polymerized and then the flexible and transparent films were obtained. Tensile moduli and strengths of the MOISS films were significantly improved as the MOI contents increased. By the addition of the isocyanate compounds, silk sericin films exhibited lower solubility to the distilled water($80^{\circ}C$) and also lower swell ratio to the distilled water(room temperature). In the effect of tensile properties and restraining the water swelling, MOI was better than AOI. BOD(biochemical oxygen demand)/TOD(theoretical oxygen demand) of the pure sericin film was almost 100% perfect level after 10 days immersion into the activated sludge. With increasing isocyanate content reacted with polar amino groups, BOD/TOD decreased. When more than 50 mol% of polar amino groups remained unreacted, sericin films could retain more biodegradability. Comparing with MOI from the viewpoint of biodegradability, AOI was more effective.

Isocyanate-Induced Occupational Asthma: Immunologic and Challenge Studies (Isocyanate에 의한 직업성 천식환자에서 임상양상과 Isocyanate 특이 IgE 항체에 관한 연구)

  • Suh, Jung-Eun;Park, Hae-Sim;Kim, Seong-Jin;Rhu, Nam-Soo;Cho, Dong-Ill;Kim, Jae-Won;Kyung, Nan-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.39 no.6
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    • pp.490-501
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    • 1992
  • Background: Isocyanate is the most significant cause of occupational asthma in this country. The mechanism of isocyanate induced bronchoconstriction is unclear. Subjects and Method: To observe its immunologic and clinical findings, we performed methacholine bronchial challenge test (MBCT), toluene diisocyanate (TDI)-bronchoprovocation test (BPT) and RAST to TDI-, diphenylmethane diisocyanate (MDI)-, and hexamethylene diisocyanate (HDI)-human serum albumin (HSA) conjugate in 22 isocyanate-sensitive asthmatic workers. Results: BPT revealed early (11), dual (5), and late only (6) asthmatic responses. Their latent period ranged from 3 to 120 months (mean:45.9 months). Three cases (13.6%)showed a negative response on initial MBCT, but following MBeT performed 24 hours after TDI-BPT revealed the development of airway hyperresponsivenss. Twelve (54.5%) workers had increased specific IgE to TDI-HSA, seven (31.8%) had to MDI-HSA, and nine (40.9%) had to HDI-HSA conjugate. The prevalence of specific IgE was not associated with latent period, type of asthmatic responses, smoking, and atopic status. After 3 months' avoidance from workplace, airway hyperresponsiveness was improved in 10 (38.3%), among 12 followed cases. Conclusion: It is suggested that isocyanate can induce IgE-mediated bronchoconstriction in 59.1% of isocyanate-sensitive asthmatic workers. Isocyanate-induced asthma can occur even though MBeT showed a negative result, and measurement of the changes of airway hyperresponsivenss after isocyanate-BPT could be helpful to diagnose isocyanate-sensitive asthma.

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A Study on Curing Rate of Non-Yellowing Type Acrylic Urethane Resins (무황변 Acrylic Urethane수지의 경화속도에 대한 연구)

  • Suh, C.S.;Park, T.W.
    • Applied Chemistry for Engineering
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    • v.5 no.4
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    • pp.743-747
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    • 1994
  • The catalytic effects of carboxylic acid and dibutyltin dilaurate(DBTL) on the curing rate of acrylic polyol with isocyanate prepolymer were investigated. In this work reaction of a biuret type aliphatic isocyanate with acrylic polyol follows the second order reaction in the thin film state. Carboxylic acid of acrylic polyol has a strong catalytic effect on the isocyanate groups and influences greatly on curing rate, also DBTL is more effective catalysis on acrylic polyol without carboxylic acid than with carboxylic acid.

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Effect of Interface on the Properties of Polyamide 6/Carbon Nanotube Nanocomposites Prepared by In-situ Anionic Ring-opening Polymerization

  • Min, Jin Hong;Huh, Mongyoung;Yun, Seok Il
    • Composites Research
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    • v.32 no.6
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    • pp.375-381
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    • 2019
  • Multiwalled carbon nanotubes (MWCNTs) are covalently functionalized with isocyanates by directly reacting commercial hydroxyl functionalized MWCNTs with excess 4,4'-methylenebis (phenyl isocyanate) (MDI) and hexamethylene diiosocyanate (HDI). HDI-modified MWCNTs results in a higher surface isocyanate density than MDI-modified MWCNTs. Anionic ring-opening polymerization of ε-caprolactam is conducted using a sodium caprolactam initiator in combination with a di-functional hexamethylene-1,6-dicarbamoylcaprolactam activator in the presence of isocyanate functionalized MWCNTs. This polymerization proceeds in a highly efficient manner at relatively low reaction temperature (150℃) and short reaction times (10 min). During the polymerization, the isocyanate functionalized MWCNTs act not only as reinforcing fillers but also as second activators. Nanocomposites with HDI modified MWCNTs exhibit higher reinforcement and faster isothermal crystallization than MDI modified MWCNTs. The results show that PA6 chains grow more effectively from HDI modified MWCNT surface than from MDI modified MWCNT surface, resulting in stronger interaction between PA6 and MWCNTs.

Preparation of Smectic Layered Polymer Networks Using Side Chain Liquid Crystalline Polymers Having Latent Reactive Monomeric Units

  • Oh, Young-Taek;Kim, Woo-Jin;Seo, Sang-Hyuk;Chang, Ji-Young
    • Macromolecular Research
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    • v.17 no.2
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    • pp.84-90
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    • 2009
  • We prepared side-chain liquid crystalline polymers comprising two monomeric units, one having a mesogenic side group that could form a smectic mesophase and the other having a phenolic group attached to the polymer backbone via a thermally reversible urethane bond. The urethane linkage between the isocyanate and phenol groups was stable at room temperature, but it cleaved to generate an isocyanate group when the temperature was increased. When annealed, the copolymers in their smectic mesophases became insoluble in common organic solvents, suggesting the formation of network structures. XRD analysis showed that the annealed polymers maintained their smectic LC structures. The crosslinking process probably proceeded via the reaction of the dissociated isocyanate groups. Some of the isocyanate groups would have first reacted with moisture in the atmosphere to yield amino groups, which underwent further reaction with other isocyanate groups, resulting in the formation of urea bonds. We presume that only polymer chains in the same layer were crosslinked by the reaction of the isocyanate groups, resulting in the formation of a layered polymer network structure. Reactions between the layers did not occur because of the wide layer spacing.