• Title/Summary/Keyword: 점착강도

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Styrene/EMA와 EMA/Styrene Core-shell latexs의 열적 안정성에 대한 고찰

  • 권재범;김남석;박근호;설수덕;이내우
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2003.05a
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    • pp.422-427
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    • 2003
  • 고분자 물질의 대부분은 유기용매를 사용하여 제조되는 경우가 일반적이었다. 이들 중에는 용제형 아크릴계 고분자는 점착강도, 내습성, 내수성 그리고 내열성 등이 우수하여 페인트, 접ㆍ점착제, 섬유 등의 산업전반에 이용되고 있으나 용제사용에 따른 화재의 위험성과 환경적인 문제점 때문에 규제의 대상이 되고 있다.(중략)

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Adhesive Properties of Emulsion PSA for Various Nonionic Sorbitan Surfactants (솔비탄계 비이온계면활성제 종류에 따른 에멀션점착제의 점착물성)

  • Lim, Tae Kyun;Lee, Myung Cheon
    • Journal of Adhesion and Interface
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    • v.13 no.4
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    • pp.182-187
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    • 2012
  • In making emulsion-type pressure sensitive adhesive (PSA), environmentally friendly sorbitan nonionic surfactants having various chemical structures were prepared and used to find out the possibility of substituting the traditional nonyl-phenyl nonionic surfactant (NPE40) by comparing their adhesive properties. Results exhibited that the PSA used NSR10-series and Tween 60 showed better adhesive properties in initial ball tack, peel strength and holding power than those of NPE40. The reason for this is their particular chemical structure and the proper ratio of hydrophobic groups to the ethylene oxide groups.

Estimation of Shear Strength and Rheological Parameters of Fine-Grained Soil Using Direct Shear Test (직접전단실험을 이용한 세립토의 전단강도 및 유변학적 정수 산정)

  • Park, Geun-Woo;Hong, Won-Taek;Lee, Jong-Sub
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.2
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    • pp.29-37
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    • 2017
  • As the behavior of the debris flow due to the torrential rains in mountain is affected by shear strength and rheological properties of the fine fraction in the ground, the evaluation of both properties is necessary to estimate the behavior of the debris flow. The objective of this study is to evaluate the shear strength and rheological properties using the direct shear apparatus. The direct shear tests are conducted for two kinds of fine-grained soil specimens, which are in dry state and liquid limit state. From the direct shear tests, shear strengths are measured according to the normal stresses applied on the specimens to evaluate the cohesion and internal friction angle. In addition, reversal shear tests are performed for the fine-grained soil specimens in liquid limit state according to the shear rate to evaluate the residual shear strength. The results of direct shear tests show that the specimen at the liquid limit state has lower internal friction angle and higher cohesion compared to the dry stated, and the residual friction angle and cohesion at the residual state are lower than those at the peak state. In the result of reversal shear test, the residual shear strength is directly proportional to the shear rate and viscosity is calculated as $73.60Pa{\cdot}s$. This study demonstrates that the direct shear apparatus can be effectively used for the evaluation of the shear strength and rheological properties of the fine-grained soils related with the debris flow.

Effects of Tri-functional Monomers on the Properties of UV-curable Pressure Sensitive Adhesives (PSAs) (삼관능 모노머의 종류 및 함량에 따른 자외선 경화형 감압 점착 필름의 특성)

  • Won, Jong-Woo;Kim, Ju-Yeol;Jang, Ki-Deog;Park, Myung-Chul;Chun, Jae Hwan;Kwon, Oh Hyeong;Hwang, Jin-Sang
    • Journal of Adhesion and Interface
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    • v.20 no.1
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    • pp.15-22
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    • 2019
  • In this study, polybutadiene based di-functional urethane acrylate oligomer (PB-UAO) were synthesized from polybutadiene diol and isophorone diisocyanate. And then, pressure sensitive adhesive films were prepared by mixing with synthesized oligomer, tri-functional acrylate monomer (Tris(2-acryloyloxyethyl) isocyanurate (TAOEIC) or Trimethylolpropane triacrylate (TMPTA) or Pentaerythritol triacrylate (PETA)), mono-functional acrylate monomer (Stearyl acrylate) and UV initiators. Effects of types and contents of trifunctional acrylate monomers on peel strength, tensile strength, elongation, thermal stability and water absorption property were studied. As the contents of tri-functional acrylate monomer increased, and as the molecular weight of tri-functional acrylate monomer decreased, peel strength, elongation and water absorption showed a tendency to decrease whereas tensile strength and thermal stability showed a tendency to increase.

Shear Strength of Weathered Granite Soil Considering Change of Saturation (포화도 변화를 고려한 화강풍화토의 전단강도)

  • Kim, Minwook;Kim, Youngmuk
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.9
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    • pp.5-14
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    • 2010
  • This study was aimed to suggest reliable information of shear strength characteristics due to change of saturation in the landfills or slopes during rainfall infiltration. According to the Mohr-Coulomb failure criteria, the characteristics of shear strength due to change of saturation were analyzed for the weathered residual soils which were sampled in the road construction site of Daejeon city. From the direct shear strength tests, the cohesions and the shear resistance angles were showed maximum values in the condition of optimum moisture content, and then decreased in the condition of wet side compaction. In this study, the cohesions were decreased more than 50% according to increasing saturation by infiltration for the compaction soils. But the reductions of the shear resistance angles were about $1{\sim}2^{\circ}$ which was small value, and thus the changes of the saturation were not nearly influenced the shear resistance angle. The influences of the saturation were seemed to very small for the residual strength parameters according to Mohr-Coulomb failure criteria.

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.

Pressure Sensitive Adhesion Performances of SIS/SBS based UV-curable Pressure Sensitive Adhesives using Thiol-ene Reaction (Thiol-ene 반응을 이용한 UV경화형 SIS/SBS계 점착제의 점착물성)

  • Lim, Dong-Hyuk;Do, Hyun-Sung;Kim, Hyun-Joong;Yoon, Goan-Hee;Bang, Jung-Suk
    • Journal of Adhesion and Interface
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    • v.6 no.3
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    • pp.19-25
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    • 2005
  • Synthetic rubber based pressure-sensitive adhesives (PSAs) usually containing SIS or SBS block copolymer, tackifier, plasticizer, and other additives are now widely used on various applications. As these PSAs are physically crosslinked and can be applied without the use of solvent, they are thermally processable and environmentally friendly. However these PSAs cannot be used in high temperature applications and in applications where solvent and chemical resistance properties are required. We developed the PSA adding UV curable system, such as thiol-ene system, to increase adhesion properties at elevated temperature. The adhesion properties such as probe tack, peel strength, shear adhesion failure temperature (SAFT) were evaluated. The probe tack test was conducted with varying probe materials and coating thickness of PSAs. Using the contact angle, the surface property of the cured PSAs was also observed.

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A Study on the Effect of Normal Stress on the Joint Shear Behavior (절리면 전단거동에서의 법선응력 영향 고찰)

  • Cho, Taechin;Suk, Jaewook
    • Tunnel and Underground Space
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    • v.23 no.3
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    • pp.203-211
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    • 2013
  • Shear behavior of joint plane has been investigated considering the magnitude of normal stresses and initial surface roughness. Shear strength of joint plane has been measured by performing the multi-stage shear test in which applied normal stress level has been increased stepwise. Multi-stage shear test within the specified normal stress range has been repeated and two types of strength parameter variation have been observed: type 1 - both cohesion and friction angle decrease, type 2 - cohesion decrease and friction angle increase. Trends of strength parameter variation for the three rock types, gneiss, granite and shale, have been investigated and the influence of initial roughness of joint plane on the sequential shear strength change for the repeated multi-stage shear tests also has been analyzed.

Analysis on Erosional Properties of Fine-Cohesive Sediments In Kunsan Coast (군산해역 미세-점착성 퇴적물의 침식특성 해석)

  • 이현승;조용준;황규남
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 2003.08a
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    • pp.222-226
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    • 2003
  • 대부분의 경우에 하구의 미세-점착성 퇴적물은 보통 무기성 광물과 유기물 및 생화학물의 혼합체이며, 광물 입자들은 주로 점토와 실트로 구성되어 있다. 이러한 혼합체의 침식특성은 사질성 퇴적물과는 달리 입자간의 응집현상에 의한 의해 크게 영향을 받으며, 응집강도는 광물질 구성, 입경분포, 유기물 함량 등으로 묘사되는 퇴적물 자체의 물리ㆍ화학적 기본특성에 따라 크게 변화하고 (Mea, 1986), 특히 저면 퇴적물의 침식 여부는 흐름 전단응력에 의한 저면퇴적물의 저항력 즉, 저면전단강도의 상대적 크기의 차이에 좌우되므로, 그 침식 특성은 저면전단강도 흑은 저면밀도로 묘사되는 저면특성에 따라 크게 변화한다(황규남 등, 2003). 또한 각 해역마다 저면 퇴적물은 퇴적물 공급원, 수동학적 조건, 생태학적 조건 등이 모두 다른 상태에서 형성된 퇴적층이므로, 저면 퇴적물의 기본특성 및 저면특성은 "site- specific" 한 성격을 갖는다. (중략)

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Development of Failure Criterion of Hot Mix Asphalt Using Triaxial Shear Strength Test (삼축압축시험을 이용한 아스팔트 혼합물의 파괴기준 개발)

  • Kim, Seong Kyum;Lee, Kwan Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.3
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    • pp.947-954
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    • 2014
  • In general, Fracture of the material is not occurring of the maximum normal stress or the maximum shear stress failure in the state. Maximum normal stress and maximum shear stress in the state of Critical coupling from being destroyed based on the Mohr-Coulomb theory. Couple of different mixtures, including permeable asphalt pavement, SMA and dense-graded asphalt mixture, were used for compression triaxial test at $45^{\circ}C$ and $60^{\circ}C$. Mohr-Coulomb theory to the analysis of compression triaxial test result of the internal friction angle $38.9^{\circ}{\sim}46.9^{\circ}$ measured somewhat irregularly, but in the case of cohesion, depending on whether the temperature and immersion of the specimen appeared differently. In addition, Indirect tensile test and compression triaxial test of the asphalt mixture to determine the correlation between compression triaxial test results assessed as cohesion and internal friction angle calculated using the theoretical Indirect tensile strength and measured indirectly tensile strength were analyzed. The Measured & Predicted IDT St values tended to be proportional.