JP2600956Y2 - Mold for vulcanizing test rubber samples - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for vulcanizing a rubber sample to be subjected to a tensile test, a low-temperature embrittlement test, and the like, and more particularly, to a rubber capable of improving the molding accuracy of a rubber sample. It relates to a mold for vulcanizing a sample.

[0002]

2. Description of the Related Art Conventionally, a mold as shown in FIG. 4 has been used as a vulcanization mold for molding a test rubber sample. This mold comprises a flat upper mold 1 and a lower mold 2, and a cavity 3 for molding the main body of the rubber sample in the lower mold 2.
And an overflow groove 4 surrounding the cavity 3.

In the above mold, unvulcanized rubber 5 slightly larger than the cavity capacity is inserted into the cavity 3 of the lower mold 2,
By placing the upper mold 1 thereon, the cavity 3 is filled with the unvulcanized rubber 5 without any gap, and the surplus unvulcanized rubber 5 is allowed to overflow the partition wall 6 and overflow into the overflow groove 4. I have. After setting the upper mold 1 and the lower mold 2 in this way, by heating them, a rubber sample is vulcanized from the unvulcanized rubber 5.

However, in the rubber vulcanization mold described above, when the upper mold 1 is set, the surplus unvulcanized rubber 5 cannot completely pass over the partition wall 6 of the lower mold 2, and a part of the rubber vulcanizates does not move. Since the rubber sample is sandwiched between the mold 1 and the mold 1, the rubber sample becomes thicker than the specified thickness. In addition, since the amount of rubber sandwiched on the partition wall 6 varies depending on physical properties such as the viscosity and hardness of the unvulcanized rubber 5, the thickness of the rubber sample changes each time the type of rubber is changed. This causes an error in the measured value of the rubber sample.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vulcanization mold for a test rubber sample which is capable of improving the thickness accuracy of the rubber sample regardless of the physical properties of the unvulcanized rubber. Is to do.

[0006]

The rubber vulcanizing mold of the present invention for achieving the above object comprises an upper mold and a lower mold.
In a vulcanization mold for a test rubber sample provided with a cavity for molding a rubber sample main body in the lower mold and an overflow groove surrounding the cavity, the height of a partition wall between the cavity and the overflow groove is increased. The cavity is formed to be at least 0.2 mm below the depth of the cavity in a region at least half the outer peripheral length of the cavity, and
-Reduced the volume of the bar flow groove and the height of the partition wall
The sum of the volume on the region and the volume of the cavity is 10
% Or more .

[0007] Since the height of the partition wall between the cavity and the overflow groove is made smaller than the depth of the cavity over a part or the entire circumference of the cavity, the unvulcanized rubber becomes thicker than the depth of the cavity. In this state, the rubber sample does not remain on the partition wall, so that the thickness accuracy of the rubber sample can be improved regardless of the physical properties of the unvulcanized rubber.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing a lower mold of a mold for vulcanizing a rectangular sheet-like rubber sample according to an embodiment of the present invention, and FIG. 2 is a sectional view of the mold. In the figure, 1,
Reference numeral 2 denotes a flat upper mold and a lower mold, respectively. The lower mold 2 is provided with a cavity 3 for molding a rubber sample main body which is rectangular in a plan view, and an overflow groove 4 surrounding the cavity 3, and between the cavity 3 and the overflow groove 4. Is a partition wall 6. The partition wall 6 is formed such that its height is lower than the depth d of the cavity 3 by 0.2 mm or more over the entire circumference. The height of the partition wall 6 is adjusted to the cavity 3
Less than 0.2 mm compared to the depth d
And the unvulcanized rubber 5 rides on the lowered portion of the partition wall 6.
It is difficult to increase the thickness of the rubber sample.
Results are inadequate. In this manner, the area where the partition wall 6 is lowered is set to extend over half or more of the outer peripheral length of the cavity 3 . Furthermore, the sum of the volume of the overflow groove 4 and the volume in the region where the height of the partition wall 6 is reduced is set to 10% or more of the volume of the cavity 3. this
Reduce the volume of the overflow groove 4 and the height of the partition wall 6
Of the cavity 3 is 10% of the volume of the cavity 3
Excess rubber is discharged to the overflow groove 4 side if it is less than
It becomes difficult to completely fill cavity 3
Therefore, the effect of improving the thickness accuracy of the rubber sample is insufficient.
You.

In the mold configured as described above, the lower mold 2
The unvulcanized rubber 5 slightly larger than its capacity is inserted into the cavity 3 and the upper mold 1 is placed thereon, so that the cavity 3 is filled with the unvulcanized rubber 5 without gaps.
The surplus unvulcanized rubber 5 overflowing from the cavity 3 gets over the lowered partition wall 6 and overflows into the overflow groove 4. After setting the upper mold 1 and the lower mold 2 in this way, by heating these, the uncured rubber 5 is removed from the cavity 3.
The rubber sample having a specified thickness corresponding to the depth d can be vulcanized. The rubber sample after molding is cut off so as to leave only a main body portion corresponding to the cavity 3, thereby completing a test rubber sample.

According to the present invention, the unvulcanized rubber 5 is provided on the partition wall 6 at a specified depth d by cutting the partition wall 6 partially or all around to reduce the height.
It is possible to suppress the residual to be thicker than that. Therefore, even when the physical properties such as the viscosity and hardness of the unvulcanized rubber 5 are variously changed, the thickness accuracy of the rubber sample can be improved regardless of the physical properties, and a test with a small measurement error can be performed.

Further, the amount of decrease in the height of the partition wall 6 is 0.2
mm or more, and can be reduced up to the bottom of the cavity 3 as shown in FIG. However,
The height of the partition wall 6 is preferably set to 1/10 or more of the cavity depth in order to easily distinguish the main body portion and the overflow portion of the rubber sample after vulcanization. The present invention provides a sample mold for a Lupke test, a sample mold for a flexo test, a sample mold for a Dimatia bending test, a sample mold for a compression test, and a sample mold for abrasion tests (Akron, Pico, Lambourn, Williams, Taber, etc.). It can be applied to various types of sample dies for testing rubber properties such as dies.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG.
A vulcanizing mold for a rectangular sheet-like rubber sample was prepared in which the height of the partition wall between the cavity and the overflow groove was varied as described below. Conventional mold As shown in FIG. 4, the height of the partition wall was made equal to the depth of the cavity over the entire circumference. The mold 1 of the present invention As shown in FIG. 2, the height of the partition wall was reduced by 0.2 mm from the depth of the cavity over the entire circumference. The mold 2 of the present invention As shown in FIG. 3, the height of the partition wall was reduced to the bottom of the cavity over the entire circumference. Experiment 1: Unvulcanized rubber having a Mooney viscosity (ML _{1 + 4} ) of 61 in a cavity of 55 cc and a thickness of 2.5 mm or 4.5 mm was placed in the cavities of the conventional mold and the molds 1 and 2 of the present invention. After inserting as a sheet material and setting the lower mold and the upper mold, these were heated to vulcanize the rubber sheet. Then, the thickness of the rubber sheet after vulcanization was measured, and the amount of increase in the thickness with respect to the cavity depth (sheet thickness-cavity depth) was obtained. The result is shown in FIG.

Experiment 2: Unvulcanized rubber having a Mooney viscosity (ML _{1 + 4} ) of 90 in a capacity of 55 cc and a thickness of 2.5 mm or 4 was placed in the cavities of the conventional mold and the molds 1 and 2 of the present invention. After inserting as a sheet material of 0.5 mm and setting the lower mold and the upper mold, these were heated to vulcanize and mold the rubber sheet. Then, the thickness of the rubber sheet after vulcanization was measured, and the thickness increase with respect to the cavity depth was determined. The result is shown in FIG. Experiment 3: Unvulcanized rubber having a Mooney viscosity (ML _{1 + 4} ) of 61 and a thickness of 4.5 mm and a capacity of 50 cc, 55 cc or 60 c were respectively placed in the cavities of the conventional mold and the molds 1 and 2 of the present invention.
After inserting as a sheet material of c and setting a lower mold and an upper mold, these were heated to vulcanize and mold a rubber sheet. Then, the thickness of the rubber sheet after vulcanization was measured, and the amount of increase in the thickness with respect to the cavity depth was obtained. The result is shown in FIG.

Experiment 4: Unvulcanized rubber having a Mooney viscosity (ML _{1 + 4} ) of 90 in a thickness of 4.5 mm, a capacity of 50 cc and a capacity of 55 cc, respectively, in the cavities of the conventional mold and the molds 1 and 2 of the present invention. Or 60c
After inserting as a sheet material of c and setting a lower mold and an upper mold, these were heated to vulcanize and mold a rubber sheet. Then, the thickness of the rubber sheet after vulcanization was measured, and the thickness increase with respect to the cavity depth was obtained. The result is shown in FIG.

The Mooney viscosities in Experiments 1 to 4 are values measured at a temperature of 100 ° C. in accordance with JIS K6300 #. As can be seen from FIGS. 5 to 8, the molds 1 and 2 of the present invention can be used with respect to the cavity depth of the vulcanized rubber sheet regardless of the thickness, weight and JIS hardness when unvulcanized rubber is inserted. The thickness increase was 0.2 mm or less, and the thickness accuracy was significantly improved as compared with the conventional mold.

[0016]

As described above, according to the present invention, a rubber test for testing includes an upper mold and a lower mold, and a cavity for molding a rubber sample body in the lower mold and an overflow groove surrounding the cavity. In the mold for vulcanizing the sample,
The height of the partition wall between the cavity and the overflow groove is made smaller than the depth of the cavity in a region of at least 1/2 of the outer peripheral length of the cavity, so that the rubber sample can be obtained regardless of the physical properties of the unvulcanized rubber. Thickness accuracy can be improved. Therefore, in a tensile test or a low-temperature embrittlement test, a test with a small measurement error can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a lower mold for a vulcanizing mold of a test rubber sample according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a vulcanizing mold according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a vulcanizing mold according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a conventional mold for vulcanizing a test rubber sample.

FIG. 5 is a diagram showing the amount of increase in the thickness of a vulcanized rubber sheet when the thickness at the time of inserting an unvulcanized rubber (Mooney viscosity 61) is varied in a test mold.

FIG. 6 is a diagram showing the amount of increase in the thickness of a vulcanized rubber sheet when the thickness at the time of insertion of an unvulcanized rubber (Mooney viscosity 90) is varied in a test mold.

FIG. 7 is a view showing an increase in the thickness of a vulcanized rubber sheet when the weight at the time of inserting an unvulcanized rubber (Mooney viscosity 61) is varied in a test mold.

FIG. 8 is a diagram showing the amount of increase in the thickness of a vulcanized rubber sheet when the weight at the time of inserting an unvulcanized rubber (Mooney viscosity: 90) is varied in a test mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper mold 2 Lower mold 3 Cavity 4 Overflow groove 5 Unvulcanized rubber 6 Partition wall

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 24 B29L 31:40 (72) Inventor Takayuki Ohno 2-1 Oiwake, Hiratsuka-shi, Kanagawa Pref. Yokohama Rubber Co., Ltd. Hiratsuka Works ( 72) Inventor Makoto Inoue 79-25, Kasabata, Kawagoe-shi, Saitama Dumbbell Co., Ltd. (56) References Jikai Sho 63-55168 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) ) G01N 1/28 G01N 33/44

Claims (1)

(57) [Scope of request for utility model registration] 1. A vulcanization mold for a test rubber sample, comprising an upper mold and a lower mold, wherein a cavity for molding a rubber sample body in the lower mold and an overflow groove surrounding the cavity are provided. The height of the partition wall between the cavity and the overflow groove is set to be greater than the depth of the cavity by at least 1/2 of the outer peripheral length of the cavity .
2 mm or more lower and the overflow groove
And the volume on the area where the height of the partition wall is reduced
A vulcanizing mold for a test rubber sample, the sum of which is 10% or more of the volume of the cavity .