Measuring and testing – Liquid analysis or analysis of the suspension of solids in a... – Viscosity
Reexamination Certificate
2000-02-07
2003-02-25
Noland, Thomas P. (Department: 2856)
Measuring and testing
Liquid analysis or analysis of the suspension of solids in a...
Viscosity
C073S054280, C073S054410, C073S843000, C073S054290
Reexamination Certificate
active
06523397
ABSTRACT:
This application is based on Japanese Patent Application No. 11-30648 (1999) filed Feb. 8, 1999, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a curing characteristics measuring apparatus which is capable of measuring curing behaviors of a thermosetting resin or a composite material containing the same and to a curing characteristics measuring method.
2. Description of the Related Art
To know whether or not a thermosetting resin or a composite material containing the same has predetermined characteristics after curing, or, whether or not curing thereof begins and completes in a predetermined time under a specific temperature or pressure, a curing characteristics test is performed. For this purpose, a test has heretofore been conducted by partly changing the shape of a die of a viscoelasticity tester for measuring vulcanization characteristics of rubber (hereinafter referred to as “vulcanization tester”).
Vulcanization testers for rubber are described in ISO3417, ISO6502, JIS K6300 and the like. Further, testers having a die devised for curing characteristics test of themosetting resins are described in Japanese Patent Application Publication No. 7-72710 (1995), Japanese Utility Model Application Publication No. 5-2841 (1993) and the like. The above-described vulcanization tester is an apparatus in which an unvulcanized rubber sample is charged in a sample chamber having a fixed surface and a rotation-vibrating drive surface, a torsional vibration is applied to the sample through the drive surface to record the changes as a curve while measuring a shearing stress generated in the sample as a vibration torque through the fixed surface or the drive surface. Still further, the die devised for curing characteristics test of thermosetting resins has devised grooves provided on the surface to prevent slipping between the die surface and the sample.
A thermosetting resin or a composite material containing the same is large in degree of volume contraction associated with curing reaction as compared to vulcanization reaction rate of rubber. Hereinafter this phenomenon is referred to as “curing shrinkage”. In the prior art curing characteristics test apparatus, even if provided with the above-described slipping prevention grooves, when the curing shrinkage is considerable, in the curing process of the sample, a gap is generated between the inner wall of the sample chamber and the sample, resulting in such problems that a torsional vibration provided from the drive surface is not effectively transmitted to the sample, and/or a shearing stress generated in the sample is substantially damped before it is transmitted completely to a torque detection mechanism. Therefore, with such a test apparatus, there is no reproducibility of data and only part of necessary characteristics can be measured.
Group (A) of curves in
FIG. 1
shows a practical example of such unsatisfactory test results. These are examples measured by repeated measurements by a prior art test apparatus of a sample which causes volume contraction during curing reaction. The test apparatus used is equipped with a die devised for curing characteristics test of thermosetting resin, which is described, for example, in Japanese Patent Application Publication No. 7-72710 (1995), Japanese Utility Model Application Publication No. 5-2841 (1993).
A prior art apparatus and measuring method will be described using a practical example. Construction of a measuring apparatus which presently is widely used is exemplified in FIG.
2
. By rotation-vibration of a drive shaft
8
, a torsional vibration is applied to a sample charged in a sample chamber
26
through a drive die
2
directly linked to the shaft
8
, and a shearing stress generated inside the sample is transmitted in the form of a vibration torque to a torque detection die
1
. Since the torque detection die
1
is supported by a torque detection mechanism
14
through a torque detection shaft
7
, the vibration torque and a temporal change thereof are recorded by electrical means or the like through the torque detection mechanism
14
.
The sample chamber
26
, in addition to the torque detection die
1
and a drive die
2
, comprises a torque detection side fixed die
3
, and a drive side fixed die
4
. Of these, the upper part from the torque detection die
1
and the torque detection side fixed die
3
is movable in upward and downward direction in the figure by an air cylinder
23
when loading/unloading the sample. On the other hand, since the drive die
2
and the drive side fixed die
4
are fixed with respect to the vertical direction in
FIG. 2
, the sample charged in the sample chamber
26
is maintained in a sealed state during measurement by a tightening pressure of the air cylinder
23
. All the components constituting the sample chamber
26
are maintained at a predetermined measurement temperature by means of appropriate heater/temperature controllers
19
,
20
,
21
and
22
. Numeral
5
indicates an upper seal,
6
is a lower seal,
10
is a motor,
11
is an eccentric rotary shaft,
12
is a crank arm,
13
is a torque arm,
15
and
16
are heaters,
17
is an upper base supporting an upper measuring part B and the like comprising the upper die
1
and the upper fixed die
3
and the like,
18
is a lower base supporting a lower measuring part A and the like comprising the lower die
2
and the lower fixed die
4
and the like, and
24
is a flash collector. Detailed construction in the vicinity of the sample chamber
26
is shown in
FIGS. 3 and 4
. Description of the respective figures will be made along with description of the measurement examples described below.
In
FIG. 3
, numeral
66
indicates a sample,
66
A is a sample overflowed into the flash collector. In
FIG. 4
, numeral
64
A indicates a cutout part of a seal plate support plate
64
,
65
A is a collar part of a seal plate
65
, and
69
is a spot facing hole for a fixing screw.
The sample
66
used in the measurement example in
FIG. 1
is an unsaturated polyester type thermosetting resin. This sample
66
is a viscous liquid having a fluidity at room temperature, and its volume contraction associated with curing is as large as about 7%. This value is one of the largest values among themosetting resins. The sample
66
is injected into the sample chamber
26
in FIG.
2
.
FIG. 3
shows an enlarged diagram of the sample chamber
26
. The shape of a torque detection die (upper die)
61
shown in
FIG. 3
is conical form, different from the example in
FIG. 2
, however, there is no substantial difference even if it is in a disk form. In addition, in the description hereinafter, for simplicity, the torque detection die
61
is referred to as an upper die, a torque detection side fixed die
63
as an upper fixed die, a drive die
62
as a lower die, and the seal plate support plate
64
as a lower fixed die.
FIG. 4
shows an exploded perspective diagram of components constituting the sample chamber
26
. The seal plate
65
and the seal plate support plate
64
combinedly function as the lower fixed die, however, for convenience of removing cured sample and cleaning after the completion of measurement, the seal plate support plate
64
and the seal plate
65
have a separable structure.
After injecting the sample
66
, the sample chamber
26
is rapidly closed, and driving of the lower die
62
shown in
FIG. 3
is started. The driving is performed in sinusoidal rotation-vibration of an amplitude angle of ±¼ degree at a frequency of 1.6 Hz about the drive shaft
8
shown in FIG.
3
. This rotation-vibration is transmitted to the sample
66
to generate a shearing stress according to its viscoelasticity inside the sample, which is transmitted as a vibration torque to the torque detection shaft
7
through the upper die
61
shown in FIG.
3
. The vibration torque is detected by the torque detection mechanism, which is directly connected, and the state of temporal changes thereof is reco
Nichigo Shoji Co., Ltd.
Noland Thomas P.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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