• Title/Summary/Keyword: rosin size

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The Particle Size distribution of Cement Binder and Rheological Properties of Paste (시멘트 혼합재의 입도분포와 페이스트 유동특성)

  • Yoo, Dong-Woo;Choi, Hyun-Kook;Lee, Seung-Heun;Lee, Se-Jin
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.2
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    • pp.103-111
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    • 2011
  • This study examined rheological properties of blast furnace slag and ash paste that are widely used as cement concrete for mineral admixture in current. In that way rheological properties of the paste of mineral admixture only was examined. The result of this study were as follow: In order to analyze that the rheological properties of the mineral admixture only, fine particles were produced with grinding machine to 3 particle sizes. These powders in general from the result of comparison with and analysis of rheological properties and the coefficient n and De values. The result that ash powder was higher in plastic viscosity and yield stress than Slag powder, and with the same n value, ash powder showed higher plastic viscosity and yield stress than Slag powder. But Slag powder in particle size distribution showed a sensitive tendency on changing in rheological properties.

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The Characteristics of Solid Mixing in a Vibrating Type Feeder and Pressure Fluctuation of Packing Materials for a Fluidized Bed Combustor (유동층 연소로에서 진동형 공급기의 고체혼합 및 충전물에 대한 압력요동 특성)

  • 김미영;김의식
    • Journal of the Korean Society of Safety
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    • v.14 no.3
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    • pp.101-109
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    • 1999
  • This study attempts to analyse the solid mixing in the feeder and the packing effect for pressure fluctuations in the fluidized bed. To study the mixing characteristics of solid in vibrating feeder for the stable operations of fluidized combustion, the system consisted of two groups of particles such that fine particles were located on the top of the coarse particles before vibratory mixing had started. The effects of packing materials on the pressure fluctuations in a fluidized bed were analysed by using a statistical method to interpret the behavior of fluidized bed. The experiments were carried out in a fluidized bed of 6.7cm-ID, and the experimental variables were particle sizes, of 115 to 1,015$\mu\textrm{m}$ in diameter and the multi-sized particles haying Rosin-Rammler and Gaussian distributions. The settled bed heights of particles to diameter ratios (L/D) were ranged from 0.5 to 2.0. And fluidizing of particles was carried out by air. The packing materials used were screen packing, and the properties of the pressure fluctuations in the fluidized bed were measured by a differential pressure transducer. The properties of the pressure fluctuations calculated were the mean, the standard deviation, and the major frequency of the power spectral density functions. From the characteristics of fluidizing, it was found that the standard deviation of pressure fluctuations could be effectively used to explain the fluidized phenomena, and the packing materials affected severely the properties of the pressure fluctuations. As a result, from the interpretation by spectral analysis, the effects of measuring radius of pressure fluctuations on standard deviation were constant in the case of the fluidized bed with and without packing materials. However, the effects of measuring the height of pressure fluctuations on standard deviations were linear increasing for the fluidized bed with packing materials, but were constant for the fluidized bed without packing materials at 4.5cm above the gas distributor. The major frequency of pressure fluctuations was found to be nearly independent of fluidized system. Also, the major frequency of pressure fluctuations decreased with increasing packing size, and it had maximum value at 10% of the packing amount.

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REACTION OF PAPER PULP AND ALKYL KETENE DIMER BY AGING TREATMENT DURING PAPERMAKIN PROCESS

  • Shin, Young-Doo;Seo, Won-Sung;Cho, Nam-Seok
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2000.11a
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    • pp.83-83
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    • 2000
  • Alkylketene dimer was known as a cellulose reactive or alkaline size because it does not require to fix to the fiber as do the traditional rosin sizes. A proposed sizing mechanism of AKD was the formation of P -ketoester bond between AKD and cellulose which provides the permanent attachment and the orientation of the hydrophobic alkylchains outward. However, some questions about the reaction had arisen and thus, the sizing mechanism of AKD has been a subject of controversy for several decades. The major concern of the controversy is that AKD is really reactive with cellulose or not in the papermaking conditions. In this study, reaction between AKD and pulp fiber was investigated, in order to find out whether AKD forms P-ketoester with pulp fiber during aging under no catalyzed neutral condition with obvious spectroscopic evidence. In addition, effect of aging treatment on the sizing development was studied. It has been disclosed that, in absence of water, AKD reacted with cellulose to form P -ketoester linkage under no catalyzed neutral condition, while, in presence of water, most of AKD was hydrolyzed to a dialkyl ketone or P -ketoacid. In addition, during the aging treatment of AKD-sized paper, its typical IR spectra bands gradually were reduced, completely disappeared after 6hr aging, and formed new absorption bands at 1707cm-' and shoulder peak at 1700cm-' which refer to the typical dialkylketone absorption bands. Therefore, the formation of P -ketoester between AKD and pulp fiber is impossible in the practical papermaking process. It could be suggested that the sizing development of AKD-sized paper is obtained by next two mechanism: 1) formation of a thin-layer of AKD on the fiber surface through melting and spreading of AKD emulsion particles by heat and 2) the hydrolysis of AKD to dialkyl ketone which has higher melting point, during drying and storage of AKD sized papers.

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Properties of Pressure-Sensitive Rubber Adhesive in a Heat Shrinkable Sheet for the Protection of Welded Part of Gas Pipe Line (가스 배관 용접부 방식용 열 수축 쉬-트의 고무계 점착제 물성)

  • Song Sung-Ku;Hwang Kyu-Suk;Kim Wonho;Chung Kyung-Young;Bae Jong-Woo;Choi Heung-Hwan;Lee Seong-Min;Shin Sung-Sik
    • Journal of the Korean Institute of Gas
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    • v.2 no.3
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    • pp.1-11
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    • 1998
  • To increase peel strength, low temperature properties and flowability of pressure sensitive adhesives(PSA) used in a heat shrinkable sheet, these properties were evaluated by changing each components in type and content. In this study, Isobutylene-co-Isoprene Rubber (IIR) which has good wetherability was selected as a base polymer. Instead of rosin ester, petroleum resin was selected as a tackifier because of superior peel strength. By decreasing petroleum resin contents, flowability of PSA was decreased. High molecular weight of polybutene was better than low molecular weight for the peel strength of PSA. Large particle size of carbon black showed better properties than small one in peel strength and brittleness temperature. By adding calcium carbonate, the cost of compound was able to be reduced. But it must be used with carbon black.

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