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Predecessor
Volume 49, Issue 7
Displaying 1-6 of 6 articles from this issue
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Koichi NAGAMI, Masahiro CHIBA1976 Volume 49 Issue 7 Pages 403-407
Published: July 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe volatiles evolved from the twelve thermosetting coatings at the baking condition were determined by mass spectrometry and colorimetric analysis. And the following results were obtained.
(1) The powder coatings using epoxy or polyester resin evolved the trace of carbon dioxide, and that using acrylic resin evolved monomers, but not carbon dioxide.
(2) The coatings using melamine-formaldehyde resin evolved formaldehyde, the quantity of which varied with heating condition.
(3) The amino compound used for the curing agent of the powder coating evolved the trace of ammonia.
(4) Toxic gases such as hydrogen cyanide or carbon monoxide were not detected.View full abstractDownload PDF (522K) -
On the Consistency of Extender PigmentsMasafumi KOJIMA1976 Volume 49 Issue 7 Pages 408-415
Published: July 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSExamining the consistency of extender pigments which have been used for the formation of wooden bases, the following result was obtained.
1. The average of plastic limit value on the non treated extender pigment is 23.7%, that of liquid limit value is 53.6% and that of plasticity number is 29.9%. About the clay used in ceramics, plastic limit value is 26.0%, liquid limit value is 109.4% and plasticity number is 83.4.
Comparing these values with those of non-treated extender pigments, they indicate the larger values.
2. Plastic limit values of heat treated extender pigments are 25. 1% at 400°C, 33.3% at 600°C and 34.0% at 800°C.
This expresses that the higher the treating temperature is, the larger the plastic limit value.
While liquid limit values are 47.5% at 400°C and 51.6% at 600°C.
But it is impossible to measure at 800°C in the case of sample No. 1, No. 3 through 9. and No. 12, because they become paste at 800°C.
About the plasticity number, the average values are 22.8 at 400°C and 18.4 at 600°C.
3. Non treated extender pigments with water contents of about 13% indicate the compressive strength value of 4kg/cm2.
Wazima diatomaceous earth and the clay used in ceramics with the water contents of 17% indicate the compressive strength of 3kg/cm2. About the heat treated extender pigments, the higher the treated temperature is, the lower the maximum of the compressive strength is.View full abstractDownload PDF (1342K) -
Drying Shrinkage of Extender Pigments and Thermal DilatationMasafumi KOJIMA1976 Volume 49 Issue 7 Pages 416-426
Published: July 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSMeasuring the drying shrinkage of the extender pigments which were non-treated and heat treated at 400°, 600° and 800°C, the following results were obtained.
(a) In the case of the initial water content of 40%, the shrinkage ratio of the perpendicular specimen to the parallel specimen of the non-treated extender pigment was 1. 8 to 2. 4. Meanwhile, that of the kaolin clay from Korea was 1.2 and that of the clay used for ceramic was 3. 4.
(b) In the case of the initial water content of 40%, the shrinkage ratio of the 45° specimen to the parallel specimen of the non-treated extender pigments was 1.0 to 2.0 and that of the non-pressed specimen was 1.0 to 1. 3. The shrinkage of the 45° specimen was nearly the same to that of the perpendicular specimen.
(c) The perpendicular specimens which were heat-treated at 400°, 600° and 800°C indicated the slightly larger shrinkage than the parallel specimens and their shrinkage ratio was 1. 1 Among the heat-treated specimens at 800°C, only No.11 specimen was possible to measure and others were paste.
(d) In the measurement of thermal dilatation, all extender pigments used in these experiments dilated abruptly in the temperature range of 550° to 600°C.View full abstractDownload PDF (1868K) -
Seisirô ITÔ, Yosiyo KUBO, Tosihide KUWAHARA1976 Volume 49 Issue 7 Pages 427-433
Published: July 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSFor the purpose of preparing a substitute pigment for toxic cobalt violet light [CO3 (AsO4) 2], the preparation of CoNH4PO4·H2O of reddish violet color was investigated.
The best reddish violet color was obtained as follows : After addition of 1.5M- (NH4) 2HPO4 solution to 1.0M-Co (<NO3) 2 solution in equal volume, the solution was adjusted to pH 6.0 by NH3 water. The color of the prepared precipitate changed gradually from pink to reddish violet by aging at 60°C for 1 hr.
By calcining CoNH4PO4·H2O at 250°C for 1 hr, the color changed from reddish violet to a vivid blue. This blue compound was recognized as CoNH4PO4 by X-ray diffraction pattern and IR spectrum. The activation energy at the dehydration was calculated 36. 7 Kcal/mol.View full abstractDownload PDF (1009K) -
Discoloration of Ammonium Cobalt (II) Phosphate Blue Pigment by Water, and Its Prevention MethodSeisirô ITÔ, Tosihide KUWAHARA1976 Volume 49 Issue 7 Pages 434-437
Published: July 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe purpose of this paper is _??_ investigate about the discoloration of CoNH4PO4 blue pigment (CNP) by water, and also about its prevention method by treatment with basic zinc carbonate (active zinc oxide : AZn).
The results obtained were as follows :
According to the standing time in water, the color of non-treated CNP changed from blue to reddish violet, and it became almost CoNH4PO4· H2O.
CNP treated with AZn at 200°C showed no change in color after the water-proof test, and no change in the structure.View full abstractDownload PDF (522K) -
Tatsuko IMAMURA, Shuichi KASAI, Masumi KOISHI1976 Volume 49 Issue 7 Pages 438-446
Published: July 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe rates of sedimentation and sedimentation volumes of two rutile-type bare titanium dioxides in water and in aqueous polyvinyl alcohol solutions were measured after the various kinds of pretreatments.
The effects of the existence of degassing on titanium dioxides and of a simple agitation or an ultrasonic treatment of suspensions were investigated in the experiments.
From the results, it was concluded as follows :
(1) The values, (rate of sedimentation × ηrel), considered as a function of apparent radius of titanium dioxide flocculate were almost equal ones at various polyvinyl alcohol concentrations in each pretreating conditions. However, these values were extremely lower ones when the suspension underwent an ultrasonic treatment.
(2) The apparent radii of titanium dioxides flocculates calculated by Steinour equation concerning the rate of sedimentation showed about half-values for an ultrasonic treatment in comparison with ones for a simple agitation.
(3) The effects of the existence of degassing on titanium dioxides were not appeared for the values described in (1) - (2). Therefore, significant effects were observed by the selection of either a simple agitation or an ultrasonic treatment.
(4) The sedimentation volumes of two rutile-type titanium dioxides treated with ultrasonic operation were about twice higher in comparison with ones in simple agitation. The reasons why the volumes increased about twice were explained qualitatively by using the simple adsorption models of polyvinyl alcohol, such as train- or loop-type, onto the surface of titanium dioxide and by the aggregate models of titanium dioxides.View full abstractDownload PDF (1302K)
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