Journal of Korea Technical Association of The Pulp and Paper Industry (펄프종이기술)

Korea Technical Association of the Pulp and Paper Industry (한국펄프종이공학회)
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Effects of PVA and CMC addition on Rheological Characteristics and Curtain Stability of GCC Based Curtain Coating Colors

PVA와 CMC 첨가가 커튼 코팅용 GCC 도공액의 유변 특성 및 커튼 안정성에 미치는 영향

  • Choi, Eun-Heui (Dept. of Forest Sciences, Seoul National University) ;
  • Kim, Chae-Hoon (Dept. of Forest Sciences, Seoul National University) ;
  • Lee, Hak-Lae (Dept. of Forest Sciences, Seoul National University)
  • 최은희 (서울대학교 농업생명과학대학 산림과학부) ;
  • 김채훈 (서울대학교 농업생명과학대학 산림과학부) ;
  • 이학래 (서울대학교 농업생명과학대학 산림과학부)
  • Received : 2010.12.10
  • Accepted : 2010.12.23
  • Published : 2010.12.30
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Abstract

Curtain stability without curtain contraction is critical for a successful operation in curtain coating, and this can be influenced by the change in particle dynamics and rheological properties of coating colors. In this study, polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) were added to control the rheology of GCC based curtain coating colors. Surface tension was increased slightly with increasing content of cobinder. Shear-thinning of viscosity was more pronounced for the CMC containing GCC coating colors. Complex modulus decreased when small amount of PVA was used as a cobinder, but it increased in other coating colors. Extensional viscosity was increased with increasing of the cobinder content, but CMC was more effective. Results indicate that pigment interaction with PVA is different from that with CMC. Dispersibility of coating colors was improved due to steric stabilization when small amounts of PVA was used, but flocculation occurred by bridging when the amount of PVA was increased. Dispersibility of coating colors was improved when small amount of CMC was added, while flocculation was observed by depletion effect when the concentration of CMC was increased in coating colors. Addition of cobinders at proper levels gave positive effects both in rheological properties and curtain stability. On the other hand, excessive amount of cobinders caused particle flocculation and this resulted in rheological and curtain stablity problems.

Keywords

References

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