JP4204502B2 - Wiper blade rubber - Google Patents

Description

  The present invention relates to a wiper blade rubber used for a wiper of an automobile or the like.

Conventionally, windshields and rear glasses of automobiles, trains, ships, aircrafts, and the like have been provided with wipers for wiping off water droplets, dirt, and the like adhering to the glass surface to ensure the driver's view.
The wiper is provided with a wiper blade rubber at a portion in contact with the glass surface. The wiper blade rubber moves in close contact with the glass surface and wipes off water droplets and the like adhering to the glass surface. As the wiper blade rubber, a rubber excellent in wiping property capable of sufficiently wiping off water droplets and dirt on the glass surface and the like is desired. In order to ensure this wiping property, the wiper blade rubber is required to have excellent physical properties such as hardness, tensile strength, and elongation in a well-balanced manner.

  Further, since the wiper blade rubber moves in close contact with the glass surface as described above, chatter may occur due to friction with the glass surface. The abnormal sound (chattering noise) generated at this time may give an uncomfortable feeling to the operator, and the occurrence of chattering may itself reduce the wipeability of the wiper blade rubber. The chattering is more likely to occur as the speed dependence of the friction coefficient between glass and rubber increases. To suppress chattering, the static friction coefficient between glass and rubber must be reduced, and the vibration absorption of rubber must be increased. Is desired.

Furthermore, as wiper blade rubber, it is difficult to wear due to friction with the glass surface, and even when deformed by being pressed against glass that has become hot under the hot summer heat, it has the property that the deformation is permanent and hardly remains, It is desired to have excellent heat resistance. Moreover, in order to prevent the wiping property from being impaired by cracking the rubber due to ozone in the air during long-term use, it is also necessary to have excellent ozone resistance.
As described above, the wiper blade rubber needs to have a small coefficient of friction with glass, a large vibration absorbability, and excellent wear resistance, heat resistance, and ozone resistance.

  As the wiper blade rubber, a rubber component whose natural rubber component is composed of natural rubber (NR), chloroprene rubber (CR), silicone rubber, ethylene-propylene-diene rubber (EPDM) or the like is generally used. Such wiper blade rubber has been coated with a coating agent such as molybdenum disulfide-based, graphite-based, fluororesin-based, or silicone-based in order to improve the wiping property. However, in the wiper blade rubber made of such a rubber component, the adhesion with the coating agent is not sufficient, and thus the coating may be peeled off when the wiper blade rubber is used for a long period of time. .

In order to improve wiping performance, for example, there is a wiper lip made of a urethane resin having a groove portion in a lip portion that comes into contact with the glass surface of the wiper blade rubber (see Patent Document 1).
The wiper lip is provided with a groove and uses urethane resin. For this reason, when the wiper lip is coated with the coating agent, the adhesion with the coating agent is excellent, and the wiping property is not easily impaired. Further, since the urethane resin is excellent in wear resistance, the wiper blade rubber made of the urethane resin is hardly worn by friction with the glass surface or the like.

  However, a wiper blade rubber using a urethane resin has a problem of low heat resistance. That is, the wiper blade rubber made of urethane resin may be deteriorated by the heat of the glass surface that is exposed to the outdoors under the hot sun and becomes high temperature. As a result, there has been a problem that the wipeability of the wiper blade rubber tends to deteriorate.

JP-A-7-215174

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a wiper blade rubber having excellent wiping properties and excellent heat resistance.

The present invention is a wiper blade rubber containing a rubber component and carbon black,
The rubber component contains 40 parts by weight or more of ester urethane rubber crosslinked with a crosslinking agent composed of an organic peroxide in 100 parts by weight of the rubber component,
The wiper blade rubber is a wiper blade rubber characterized by containing 20 to 50 parts by weight of the carbon black with respect to 100 parts by weight of the rubber component.

  In the wiper blade rubber of the present invention, the rubber component contains a specific amount of an ester-based urethane rubber crosslinked with a crosslinking agent composed of an organic peroxide. Such a rubber component is superior in heat resistance as compared to other urethane rubbers crosslinked with, for example, a sulfur-based crosslinking agent. Therefore, the wiper blade rubber is excellent in heat resistance.

  Moreover, since the rubber component contains an ester-based urethane rubber, the wiper blade rubber is excellent in wear resistance, and for example, a coating such as molybdenum disulfide-based, graphite-based, fluororesin-based, and silicone-based coatings. Excellent adhesion to the agent. Therefore, even if the above coating agent is applied to the wiper blade rubber in order to improve its wiping property, the coating agent is hardly peeled off, the wiping property is hardly impaired, and chattering is not easily generated. Become.

  The wiper blade rubber contains the specific amount of carbon black. Therefore, the wiper blade rubber has a good balance of physical properties such as hardness, strength and flexibility, and has excellent wiping properties as a wiper blade rubber. In addition, the processability is excellent.

  Thus, according to the present invention, it is possible to provide a wiper blade rubber having excellent wiping properties and excellent heat resistance.

Next, an embodiment of the present invention will be described.
The wiper blade rubber contains 20 to 50 parts by weight of the carbon black with respect to 100 parts by weight of the rubber component.
When the content of the carbon black is less than 20 parts by weight, the hardness and strength of the wiper blade rubber are lowered, and the wear resistance may be lowered. On the other hand, when it exceeds 50 parts by weight, the hardness becomes too high, and there is a possibility that the wiping property may be impaired due to less rubber deflection at the time of wiping.

The rubber component of the wiper blade rubber contains 40 parts by weight or more of ester urethane rubber crosslinked with a crosslinking agent made of an organic peroxide in 100 parts by weight of the rubber component.
When the said ester urethane rubber is less than 40 weight part, there exists a possibility that abrasion resistance may be inferior and adhesiveness with a coating agent may fall.

Specific examples of the crosslinking agent comprising an organic peroxide include 1,1-bis (tertiary butylperoxin) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di- (Tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, tert-butylcumyl peroxide, di (tert-butylperoxy) -m-diisopropylbenzene, di -Tertiary butyl peroxide, 1,3-di (tertiary butyl peroxyisopropyl) benzene, dicumyl peroxide and the like.
The ester urethane rubber is a urethane rubber having an ester bond in the main chain.

The ester-based urethane rubber is preferably crosslinked using 4 to 12 parts by weight of the crosslinking agent with respect to 100 parts by weight of the rubber component.
When the crosslinking agent is less than 4 parts by weight, the rubber component is weakly crosslinked, and the wiper blade rubber may be reduced in hardness and strength. On the other hand, when it exceeds 12 parts by weight, the rubber component is strongly crosslinked and the flexibility becomes low, and the wipeability of the wiper blade rubber may be impaired. More preferably, the amount of the crosslinking agent is 6 to 10 parts by weight with respect to 100 parts by weight of the rubber component.

Moreover, it is preferable that the said rubber component contains 20-60 weight part of blend rubber | gum which does not contain the ester bond which is easy to hydrolyze in the said rubber component 100 weight part of this rubber component.
The blend rubber is preferably at least one selected from ether-based urethane rubber, hydrogenated nitrile butadiene rubber, ethylene-propylene-diene rubber, and natural rubber.
In these cases, the resistance to hydrolyzability of the wiper blade rubber can be improved. In general, urethane has a property that it is relatively easily hydrolyzed, and the wiper blade rubber contains an ester-based urethane, so that the resistance to hydrolysis is not so high. Therefore, as described above, the resistance to hydrolysis of the wiper blade rubber can be improved by incorporating the blend rubber.

  When the content of the blend rubber is less than 20 parts by weight, the rubber component may be easily hydrolyzed. On the other hand, when the amount exceeds 60 parts by weight, permanent deformation due to heat resistance may increase.

In addition, the wiper blade rubber preferably contains 1 to 3 parts by weight of a hydrolysis inhibitor with respect to 100 parts by weight of the rubber component.
In this case, the resistance to the hydrolysis of the wiper blade rubber can be further improved. When content of the said hydrolysis inhibitor is less than 1 weight part, there exists a possibility that the improvement effect with respect to a hydrolysis may not fully be exhibited. When the amount exceeds 3 parts by weight, an effect commensurate with the content cannot be obtained, which may lead to an increase in cost.
As the hydrolysis inhibitor, for example, a carbodiimide type or an oxazoline type can be used.

  Moreover, a coating agent can be applied to the wiper blade rubber in order to improve the wiping property of the wiper blade rubber against water droplets or dirt, or to suppress chatter. Examples of such coating agents include molybdenum disulfide-based, graphite-based, fluororesin-based, and silicone-based coating agents. In consideration of adhesion to the wiper blade rubber, the binder of the coating agent is preferably a urethane type.

Example 1
Next, an embodiment of the wiper blade rubber of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the wiper blade rubber 1 of this example is provided on a wiper of an automobile or the like. The wiper blade rubber 1 of this example is mounted on a wiper frame and used for wiping off water droplets and dirt on a windshield or rear glass of an automobile or the like.

  The wiper blade rubber 1 contains a rubber component and carbon black. The rubber component contains 40 parts by weight or more of ester urethane rubber crosslinked with a crosslinking agent made of an organic peroxide (peroxide; PO). In this example, the ester-based urethane rubber is Urepan 643G manufactured by Bayer Corporation, and the organic peroxide is dicumyl peroxide. The wiper blade rubber 1 of this example contains 30 parts by weight of carbon black with respect to 100 parts by weight of the rubber component.

  The wiper blade rubber of this example contains 0.5 parts by weight of stearic acid, 2 parts by weight of aromatic polycarbodiimide as a hydrolysis inhibitor, and 10 parts by weight of oil with respect to 100 parts by weight of the rubber component. To do.

Hereinafter, the manufacturing method of the wiper blade rubber of this example will be described.
First, 100 parts by weight of an ester urethane rubber was prepared, and the ester urethane rubber and 0.5 part by weight of stearic acid were kneaded by a kneader such as an intermix, kneader, Banbury mixer, or an oven roll. Next, 30 parts by weight of carbon black, 10 parts by weight of oil and 2 parts by weight of hydrolysis inhibitor were added and further kneaded.

Thereafter, 8 parts by weight of a crosslinking agent composed of an organic peroxide is added and kneaded with respect to 100 parts by weight of the ester urethane rubber, and the kneaded product is 150 using an injection molding machine, compression molding machine, vulcanizing press, or the like. Vulcanization molding was performed at a temperature of from C to 200 C for about 3 to 20 minutes.
Thus, as shown in FIG.1 and FIG.2, the wiper blade rubber | gum 1 was produced.

  In the wiper blade rubber 1 of this example, the rubber component is made of ester urethane rubber crosslinked with a crosslinking agent composed of an organic peroxide. Such a rubber component is excellent in heat resistance as compared with other urethane rubbers, sulfur-crosslinked rubbers, and the like. Therefore, the wiper blade rubber is excellent in heat resistance.

  Further, in the wiper blade 1, since the rubber component is made of ester urethane rubber, the wiper blade rubber 1 is excellent in ozone resistance, vibration absorption, and wear resistance, and also has excellent adhesion to the coating agent. ing. Therefore, in order to improve the wiping property on the surface of the wiper blade rubber 1, for example, even if a coating agent such as molybdenum, graphite, fluororesin, or silicone is applied, the coating agent is hardly peeled off.

  Further, the wiper blade rubber of this example contains 30 parts by weight of carbon black with respect to 100 parts by weight of the ester urethane rubber which is a rubber component. Therefore, the wiper blade rubber 1 has an excellent balance of hardness, strength, and processability, and has excellent wiping properties.

  Thus, according to this example, it is possible to provide a wiper blade rubber having excellent wiping properties and excellent workability and heat resistance.

(Experimental example 1)
In this example, in order to examine various characteristics of the wiper blade rubber, a test piece (sample E1) having the same composition as that of the wiper blade rubber prepared in Example 1 was prepared, and the characteristics were evaluated.

That is, first, a test piece having the same composition as that of the wiper blade rubber prepared in Example 1 was prepared. This is designated as Sample E1.
Sample E1 was then measured for its hardness, tensile strength, elongation, heat resistance (change in hardness, rate of change in strength, rate of change in elongation, permanent elongation), acron wear, tan δ, and the like.

Hardness (type A durometer) was measured in accordance with JIS K6253.
Further, the tensile strength (MPa) and elongation were measured at room temperature (23 ± 2 ° C.) in accordance with JIS K6251.

Also, the change in hardness (point), tensile strength change rate (%), and elongation change rate (%)
According to the rule of K6257, it was carried out under heating conditions of 80 ° C. and 70 hours.
Permanent elongation was measured in accordance with the provisions of JIS K6262 by holding at 80 ° C. for 48 hours at an elongation rate of 100%.
Akron abrasion (cm ³ ) was measured in accordance with JIS K6264.

Further, tan δ was measured as follows.
That is, first, a strip-shaped test piece having a length of 50 mm, a width of 5 mm, and a thickness of 2.2 mm was prepared. Then, using this test piece, JIS
The dynamic characteristics in the tensile direction were measured from a low temperature to a high temperature with an amplitude of 0.5% in accordance with K6394. Thereafter, tan δ at 1024 Hz with 10 ° C. as the reference temperature was calculated from the temperature-time conversion rule.
The above results are shown in Table 1 described later.

The sample E1 is prepared using an organic peroxide-based crosslinking agent. Next, for comparison with the sample E1, three types of test pieces (samples C1 to C3) prepared using a sulfur-based crosslinking agent were prepared, and these characteristics were evaluated in the same manner as the sample E1.
That is, sample C1 contains natural rubber (NR) as a rubber component, and was prepared using 2 parts by weight of a sulfur-based crosslinking agent with respect to 100 parts by weight of the natural rubber. Sample C1 consists of 100 parts by weight of natural rubber, 50 parts by weight of carbon black, 1 part by weight of stearic acid, 5 parts by weight of zinc oxide, 2 parts by weight of a thiuram vulcanization accelerator, and 1 part of a paraffinic antioxidant. It contains 2 parts by weight and 2 parts by weight of an amine-based antioxidant.

  Sample C2 contains ester urethane rubber (U1) as a rubber component, and is prepared using 2 parts by weight of a sulfur-based crosslinking agent with respect to 100 parts by weight of ester urethane rubber. Sample C2 comprises 100 parts by weight of ester urethane rubber, 30 parts by weight of carbon black, 10 parts by weight of oil, 0.5 parts by weight of stearic acid, 1.5 parts by weight of thiuram vulcanization accelerator, and water It contains 2 parts by weight of a decomposition inhibitor.

Sample C3 contains ether-based urethane rubber (U2) as a rubber component, and is prepared using 2 parts by weight of a sulfur-based crosslinking agent with respect to 100 parts by weight of ether-based urethane rubber. Sample C3 comprises 100 parts by weight of ether-based urethane rubber, 30 parts by weight of carbon black, 10 parts by weight of oil, 0.5 parts by weight of stearic acid, 1.5 parts by weight of thiuram vulcanization accelerator, and water It contains 2 parts by weight of a decomposition inhibitor.
For sample C1 to sample C3, as in sample E1, hardness, tensile strength, elongation, heat resistance (change in hardness, rate of change in strength, rate of change in elongation, permanent elongation), acron wear, and tan δ Etc. were measured. The results are shown in Table 1 below.

As is known from Table 1, it can be seen that the sample E1 is superior in heat resistance, wear resistance, and vibration absorption compared to the samples C1 to C3.
That is, Sample E1 has a small change in hardness, a change rate in tensile strength, a change rate in elongation, and a change in permanent elongation before and after heating at a temperature of 80 ° C. for 70 hours. On the other hand, in sample C2 and sample C3, the hardness change, tensile strength change rate, elongation change rate, and permanent elongation all changed greatly before and after heating and deteriorated. In addition, the heat resistance of the sample C1 was almost the same as that of the sample E1, but there was a problem that the wear resistance was worse than that of the sample E1, and tan δ was small and vibration absorption was poor.

  Moreover, the sample E1 showed the characteristic whose hardness, tensile strength, and elongation are comparable as the sample C1-sample C3. From this, the sample E1 has the same degree of hardness, tensile strength, and elongation as those of the samples C1 to C3, and more excellent heat resistance and wear resistance than the samples C1 to C3. It can also be seen that it exhibits vibration absorption. Therefore, the wiper blade rubber having the same composition as that of the sample E1 has excellent wiping properties and excellent workability and heat resistance.

(Experimental example 2)
In this example, a test piece similar to that of the sample E1 was produced by changing the amount of the organic peroxide as a cross-linking agent, and the characteristics were examined.
That is, first, the amount of the organic peroxide with respect to 100 parts by weight of the ester-based urethane rubber was 4 parts by weight, and the others were prepared in the same manner as the sample E1. This is designated as Sample E2.
Moreover, the amount of the organic peroxide with respect to 100 parts by weight of the ester-based urethane rubber was 12 parts by weight, and the other test pieces were prepared in the same manner as the sample E1. This is designated as Sample E3.
The blending compositions of the sample E2 and the sample E3 are shown in Table 2 below.

  Next, in the same manner as in Experimental Example 1, the samples E2 and E3 were evaluated for hardness, tensile strength, elongation, and heat resistance (change in hardness, rate of change in strength, rate of change in elongation, permanent elongation). It was. The results are shown in Table 2. For comparison, Table 2 also shows the measurement results of the sample E1 measured in Experimental Example 1, that is, the test piece prepared using 8 parts by weight of the crosslinking agent with respect to 100 parts by weight of the rubber component.

  As is known from Table 2, all of the samples E1 to E3 have small changes in hardness, change in tensile strength, change in elongation, and change in permanent elongation before and after heating at a temperature of 80 ° C. for 70 hours. It had heat resistance enough to be applied to wiper blade rubber. Moreover, it is understood that the hardness, tensile strength, and elongation are excellent in balance and suitable for wiper blade rubber. Therefore, when the wiper blade rubber is crosslinked using 4 to 12 parts by weight of a crosslinking agent with respect to 100 parts by weight of the rubber component, a rubber having excellent heat resistance, wiping property and processability can be obtained.

  Further, when comparing the sample E1 and the sample E2, in the sample E2, the hardness and the tensile strength were slightly decreased, and the permanent elongation was increased. Moreover, when the sample E1 and the sample E3 are compared, in the sample E3, hardness became large and tensile strength and elongation were falling. These changes in properties do not necessarily have a large effect on the wiper blade rubber. However, as the wiper blade rubber, more preferably, the amount of the crosslinking agent is 6 to 10 parts by weight with respect to 100 parts by weight of the rubber component.

(Experimental example 3)
In this example, a test piece in which a blend rubber is blended with ester-based urethane rubber as a rubber component is prepared, and its resistance to hydrolysis is examined.
First, ether urethane rubber, hydrogenated nitrile butadiene rubber (HNBR), ethylene-propylene-diene rubber (EPDM), and natural rubber (NR) were prepared as blend rubbers.
Next, 60 parts by weight of ester urethane rubber and 40 parts by weight of ether urethane rubber and 0.5 parts by weight of stearic acid were kneaded with a kneader such as an intermix, kneader, Banbury mixer, or an oven roll.

  Next, 30 parts by weight of carbon black, 10 parts by weight of oil, and 2 parts by weight of hydrolysis inhibitor were added and further kneaded. Thereafter, 8 parts by weight of a crosslinking agent composed of an organic peroxide is added and kneaded, and the kneaded product is vulcanized at 150 ° C. to 200 ° C. for about 3 to 20 minutes using an injection molding machine, compression molding machine, vulcanizing press or the like. A sheet was formed and punched out with a JIS No. 1 dumbbell to prepare a test piece. This is designated as Sample E5. The composition of Sample E5 is shown in Table 3 below.

  In sample E5, ether type urethane rubber was used as the blend rubber, but instead of ether type urethane rubber, HNBR, EPDM, and NR were used, and the other three test pieces were used in the same manner as in sample E5. Produced. These are designated as Sample E6 to Sample E8, respectively. The blending compositions of Sample E6 to Sample E8 are shown in Table 3 below.

  In this example, a test piece (JIS No. 1 dumbbell) having the same composition as that of the sample E1 prepared in Experimental Example 1 was prepared. This was designated as Sample E4. The compounding composition of Sample E4 is shown in Table 3 below.

  Next, the resistance to hydrolysis (hydrolysis resistance) of the samples E4 to E7 was examined. Specifically, using a No. 1 dumbbell test piece, an outdoor exposure test was performed under the condition of 30% elongation, and pinhole cracks on the surface of the test piece were visually confirmed. The time (days) until the pinhole crack occurs was measured, and the result is shown in Table 3.

As is known from Table 3, Sample E5 to Sample E8 containing blended rubber have a longer time (days) until pinhole cracks are generated than Sample E4. That is, it turns out that hydrolysis resistance can be improved by blending blend rubber.
The urethane of the rubber component in this example generally has the property of easily causing hydrolysis and has low hydrolysis resistance. It turns out that the tolerance with respect to a hydrolysis can be improved by containing the said blend rubber like the said sample E5-sample E8.

1 is a schematic view of a wiper blade rubber according to Example 1. FIG. Sectional drawing of the wiper blade rubber | gum concerning Example 1. FIG.

Explanation of symbols

  1 Wiper blade rubber

Claims (5)

A wiper blade rubber containing a rubber component and carbon black,
The rubber component contains 40 parts by weight or more of ester urethane rubber crosslinked with a crosslinking agent composed of an organic peroxide in 100 parts by weight of the rubber component,
The wiper blade rubber comprises 20 to 50 parts by weight of the carbon black with respect to 100 parts by weight of the rubber component.   2. The wiper blade rubber according to claim 1, wherein the ester-based urethane rubber is crosslinked using 4 to 12 parts by weight of the crosslinking agent with respect to 100 parts by weight of the rubber component.   The wiper blade rubber according to claim 1 or 2, wherein the rubber component contains 20 to 60 parts by weight of a blend rubber not containing an ester bond in 100 parts by weight of the rubber component.   4. The wiper blade rubber according to claim 3, wherein the blend rubber is at least one selected from ether-based urethane rubber, hydrogenated nitrile butadiene rubber, ethylene-propylene-diene rubber, and natural rubber.   The wiper blade rubber according to any one of claims 1 to 4, wherein the wiper blade rubber contains 1 to 3 parts by weight of a hydrolysis inhibitor with respect to 100 parts by weight of the rubber component.

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