Study on rough‐surface biaxially oriented polypropylene film. I. Formation of β‐form crystals in sheet cast with T‐die extruder

Fujiyama, Mitsuyoshi; Kawamura, Yasumi; Wakino, Tetsuo; Okamoto, Tomomi

doi:10.1002/app.1988.070360501

Cited by 34 publications

(12 citation statements)

References 31 publications

(2 reference statements)

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“…1 It is a well-known fact that there are some crystal types of PP with different crystal systems, and the surface roughnesses of biaxially oriented polypropylene (BOPP) films have been investigated in association with crystal types. [2][3][4][5][6][7][8] Many basic studies have been reported on the formation of a and b crystals. [9][10][11][12][13][14] Natta and Corradini 9 reported in their paper in 1960 that the unit lattice of the a crystal is the monoclinic system, and now, it is known to be the most dominant crystal in PP.…”

Section: Introductionmentioning

confidence: 99%

Crater formation mechanism on the surface of a biaxially oriented polypropylene film

Tamura¹,

Takino

Yamada

et al. 2012

J of Applied Polymer Sci

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Biaxially oriented polypropylene (BOPP) films are used in a variety of areas around the world. They are especially suited for food packaging and industrial usages due to their high productivity. Many studies on stretchability regarding crystal structure changes have been reported by various researchers, since the machine speed has been increasing and the demand to produce thinner films has been becoming more important.Furthermore, a number of studies on the surface structure of BOPP films with crater-like roughness have been reported since the 1980's. Although the crater-like surface roughness was formed under specific film process conditions, the formation mechanism and the controlling method of the crater-like film surface are yet to be clarified. In this report, the authors demonstrate a new hypothesis as to the crater-like film surface roughness formation mechanism by analyzing the morphology of the surface layer of polypropylene (PP) sheets and by investigating the relationship between the surface structure changes and the entire structure changes. As a result, it was found that it needs to have over critical crystallization time in order to form the crater on the surface of BOPP film, and the crater formation mechanism was closely related not only to the surface structure changes but also to the deforming phenomenon of spherulite in PP sheet during stretching. Furthermore, this report will show the controlling factors in the formation of the crater structure from the view point of production conditions.

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Section: Introductionmentioning

confidence: 99%

Crater formation mechanism on the surface of a biaxially oriented polypropylene film

Tamura¹,

Takino

Yamada

et al. 2012

J of Applied Polymer Sci

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“…Although PP containing β-crystal nucleator like γquinacridone is used for the manufacturing of porous or rough-surface sheets and films [2], it is scarcely used in the injection molding field and the study on the structures and properties of the injection moldings is a few [3,4]. Varga et al [3] studied the β-crystal content in injection moldings of a γ-quinacridone-added PP and found that the skin layer was composed of α-crystals and the core layer was composed of αand β-crystals or β-crystals alone depending on * Mail address: Dr. M. Fujiyama, Plastics Research Laboratory, Tokuyama Corp., Tokuyatna-shi, Yamaguchi-ken 745, Japan the molding conditions.…”

Section: Introductionmentioning

confidence: 99%

Structures and Properties of Injection Moldings of β-Crystal Nucleator-Added Polypropylenes

Fujiyama

1995

International Polymer Processing

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An isotactic polypropylene homopolymer (PP) was added with 0 to 10000 ppm of γ-quinacridone, a β-crystal nucleator of PP. Flexural test specimens were injection-molded from the PP at cylinder temperatures of 200 to 320 °C and the structures and properties have been studied. The results can be summarized as follows: The crystallization temperature increases with γ-quinacridone content. The β-crystal content decreases with increasing cylinder temperature and shows a maximum at a γ-quinacridone content of about 100 ppm. The thickness of the skin layer scarcely depends on γ-quinacridone content. The orientation of β-crystals decreases with increasing cylinder temperature. It is high at the surface regions and decreases toward the interior. The Izod impact strength increases with γ-quinacridone content. The degree of the increase is higher as the β-crystal content is higher and reaches more than threefold in the highest case. The flexural modulus and strength decrease by about 10 % in the highest case. The heat distortion temperature increases with γ-quinacridone content. The mold shrinkage increases with γ-quinacridone content. From these results, it is concluded that the injection moldings of PPs containing γ-quinacridone are superior in impact strength and heat resistance.

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“…When the melt temperature exceeds 260°C, then the ␤-crystal does not develop in spite of a great content of nucleator. 13 In fiber-forming conditions, the solidifying polymer melt is submitted to strong orientation. Under the orientation polymer, crystallization occurs much faster on row nuclei.…”

Section: Wide-angle X-ray Scatteringmentioning

confidence: 99%

Influence of heat-stabilization on supermolecular structure of colored PP fibers

Broda

Ślusarczyk

Włochowicz

1999

J. Appl. Polym. Sci.

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Investigations of supermolecular structure and tensile properties of colored heat-stabilized fibers were carried out. For fiber coloring, chosen organic pigments with differentiated nucleating properties were used. It was stated that during the fiber formation, a fibrillar-lamellar structure with ␣-crystals is formed. In fibers colored with a quinacridone pigment, the minimal number of ␤-crystals was observed. During heat-stabilization, perfecting of the supermolecular structure of the fiber occurs. Because of pigments, the process of rebuilding occurs more intensively and leads to formation of a more stable structure with higher crystallinity.

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Study on rough‐surface biaxially oriented polypropylene film. I. Formation of β‐form crystals in sheet cast with T‐die extruder

Cited by 34 publications

References 31 publications

Crater formation mechanism on the surface of a biaxially oriented polypropylene film

Crater formation mechanism on the surface of a biaxially oriented polypropylene film

Structures and Properties of Injection Moldings of β-Crystal Nucleator-Added Polypropylenes

Influence of heat-stabilization on supermolecular structure of colored PP fibers

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