JPH05209101A - Wiper blade rubber - Google Patents

Abstract

PURPOSE:To obtain a wiper blade rubber having excellent abrasion resistance, low frictional characteristics and weather resistance, causing no stick slip phenomenon and streak and not blocking the field of view. CONSTITUTION:The objective rubber is formed of a lubricating rubber composition in at least the sliding face wherein the lubricating rubber composition consists of a thermoplastic fluororesin which is the first essential component, a fluorine rubber which is the second essential component and a low molecular weight fluorine-containing polymer which is the third essential component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiper blade rubber.

[0002]

2. Description of the Related Art A wiper for an automobile comprises a wiper blade rubber that comes into contact with glass, a wiper blade that supports the wiper blade rubber, an arm that supports the wiper blade, and the like.

Conventionally, chloroprene rubber or the like has been used as the wiper blade rubber. However,
Since these are basically water-lubricated by rain, such a conventional wiper blade rubber has the following problems.

When the water content is low at the time of light rain, the coefficient of friction is large, so that stick-slip or the like occurs.

Since the abrasion property is inferior, local abrasion is caused by sand and dust adhering to the glass, and it is easy to form streaks when the glass is wiped during rainfall.

Since the weather resistance is poor, the rubber deteriorates quickly. It will be deteriorated by window washer liquid.

The object of the present invention is to solve the above-mentioned conventional problems, to provide excellent wear resistance, low friction characteristics, and weather resistance, to prevent stick-slip phenomenon and streaks, and to obstruct the visibility. There is no wiper blade rubber to provide.

[0008]

In a wiper blade rubber according to the present invention, at least a sliding surface is formed of a lubricating rubber composition, and the lubricating rubber composition comprises a thermoplastic fluororesin which is a first essential component, It is characterized by comprising a fluororubber which is the second essential component, and a low molecular weight fluoropolymer which is the third essential component.

The wiper blade rubber according to the present invention comprises:
It is not limited to automobiles, but can be used in a wide range of fields such as trains, ships, airplanes and glass cleaning tools.

In the present invention, the thermoplastic fluororesin which is the first essential component is a polymer having a carbon chain in the main chain and a fluorine bond in the side chain. Examples of such a thermoplastic fluororesin include tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA), tetrafluoroethylene.
Hexafluoropropylene / perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as EPE), tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter abbreviated as FEP), tetrafluoroethylene /
Ethylene copolymer (hereinafter abbreviated as ETFE), trifluorochloroethylene polymer (hereinafter abbreviated as CTFE), trifluorochloroethylene / ethylene copolymer (hereinafter abbreviated as ECTFE), polyvinyl fluoride (hereinafter PVF and (Abbreviated) and polyvinylidene fluoride (hereinafter abbreviated as PVDE) are preferably one or more polymers selected from the group consisting of: In particular, ETFE, PFA and FEP are preferable in consideration of not forming fibers in the kneading step, ease of kneading such as meltability, and maintenance of rubber-like elasticity of the final product. In ETFE, MI value (melt index) is 300 ° C, 216
It is preferably 1 to 20 g / 10 min at 0 g.

Any of the above resins can be produced by various polymerization methods such as catalyst emulsion polymerization, suspension polymerization, catalyst solution polymerization, gas phase polymerization and ionizing radiation irradiation polymerization. It is desirable that the molecular weight is 50,000 or less.
It is particularly preferable that the value exceeds 00 and is almost 20000 or less.

As a typical example corresponding to the above conditions, the above-mentioned PFA PF manufactured by Mitsui DuPont Fluorochemical Co.
AMP10, FEP Teflon FEP100 manufactured by Mitsui DuPont Fluorochemicals, ETFE Aflon COP manufactured by Asahi Glass Co., Ltd. CTFE, NEOFLON CTFE manufactured by Daikin Industries, KPV manufactured by Kureha Chemical Co., Ltd.
Examples include polymers and PVF Tedlar manufactured by DuPont.

In the present invention, the fluororubber is a polymer or copolymer of unit monomers containing one or more fluorine atoms on average, and has a glass transition temperature of room temperature or lower and rubber-like elasticity at room temperature. There is no particular limitation as long as it has, and a wide range can be exemplified.

Examples of the polymerization method of fluororubber include bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, catalyst polymerization, ionizing radiation polymerization, and redox polymerization. Further, the molecular weight of the fluororubber is usually preferably 50,000 or more, and the one having a high molecular weight as much as possible obtains a good result. Therefore, it is more preferably 70,000 or more, particularly preferably 100,000 to 250,000. Use one.

Typical examples corresponding to the above conditions are tetrafluoroethylene / propylene copolymer Afras manufactured by Asahi Glass Co., Ltd., vinylidene fluoride / hexafluoropropylene copolymer DuPont / Showa Denko Viton, and fluorine. Fluorosilicone / hexafluoropropylene / tetrafluoroethylene copolymer Technofluon made by Montefluos, fluorosilicone elastomer Dow Corning Silastic LS, phosphazene elastomer made by Firestone PN
Examples thereof include F and perfluoroelastomers such as Daiel Perflo manufactured by Daikin Industries, Ltd.

The composition obtained by mixing the above-mentioned fluororubber and thermoplastic fluororesin has characteristics as an elastic body. In the present invention, the low molecular weight fluoropolymer, which is the third essential component, is added in order to impart even more excellent sliding properties to such an elastic body.

In the present invention, the low molecular weight fluorine-containing polymer means tetrafluoroethylene (TFE), a fluoropolyether having a main structural unit —C _n F _2n —O— (n is an integer of 1 to 4), Structural unit

[0018]

[Chemical 1]

Among the polyfluoroalkyl group-containing compounds (having 2 to 20 carbon atoms) having, for example, those having a molecular weight of 50,000 or less. In order to impart excellent sliding properties, it is particularly preferable that the low molecular weight fluoropolymer has a molecular weight of 5,000 or less. Among such low molecular weight fluorinated polymers, those having an average particle size of 5 μm or less of the tetrafluoroethylene polymer represented by the following formula are particularly preferable.

[0020]

[Chemical 2]

Examples of such materials include Vydalx AR manufactured by DuPont and Furuon Lubricant L169 manufactured by Asahi Glass Co., Ltd.

Next, (the n 1 to 4 integer) -C _n F _2n -O- mean molecular weight of 50,000 or less fluoropolyethers having a main structural unit of,

[0023]

[Chemical 3]

Examples include the following: Such polymers are those having a structural unit containing a functional group such as an isocyanate group, a hydroxyl group, a carboxyl group, and an ester group in order to improve the affinity (adhesion) with other compounding materials and additives. desirable.

Specific examples of such fluoropolyethers include the following.

[0026]

[Chemical 4]

These fluoropolyethers may be used alone or in combination. Further, a fluoropolyether having activated hydrogen as a functional group and an isocyanate compound having no polyfluoropolyether group may be used in combination. Further, a fluoropolyether having an isocyanate group, diamines not containing various fluoropolyether groups, triamines, or diols not containing various fluoropolyether groups,
A method of using triols together may be adopted.

In particular, it is preferable to use a fluoropolyether in combination so that the functional groups react with each other to increase the molecular weight. As such, it is likewise desirable to combine, for example, those having units containing isocyanate groups with those having units containing hydroxyl groups.

Examples of the polyfluoroalkyl group-containing compound include compounds having a polyfluoroalkyl group as shown below.

[0030]

[Chemical 5]

Those having the above polyfluoroalkyl group (having 2 to 20 carbon atoms) and having an average molecular weight of 50,000 or less include:

[0032]

[Chemical 6]

And the like, a polymer of a reaction product of a compound having a reactive group and a polyfluoroalkyl group with an ethylenically unsaturated compound having a group which reacts with the reactive group (eg, fluoroalkyl acrylate), and Examples thereof include a reaction product of a compound having a reactive group and a polyfluoroalkyl group with various polymers having a group that reacts with the reactive group, or a polycondensation product of the compound.

Like the above-mentioned fluoropolyether, the polyfluoroalkyl group-containing compound is a functional group having a high affinity, such as an isocyanate group, for improving the affinity (adhesion) with other compounding materials and additives. A compound having a unit containing a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an amino group, a sulfone group and the like is preferable.

These polyfluoroalkyl group-containing compounds may be used alone or in combination. Further, a polyfluoroalkyl group-containing compound having a reactive group having activated hydrogen and an isocyanate compound having no polyfluoroalkyl group may be used in combination. Also,
Adopting a method such as combining a polyfluoroalkyl group-containing compound having an isocyanate group with various polyfluoroalkyl group-free diamines, triamines or various polyfluoroalkyl group-free diols, triols, etc. May be.

The combination of functional groups is preferable from the viewpoint of increasing the strength, and specifically, it has a polyfluoroalkyl group having 2 to 20 carbon atoms and is selected from a hydroxyl group, a mercapto group, a carboxyl group and an amino group. Combination with a fluorine-containing polymer containing at least one kind, or 2 to 20 carbon atoms
A fluoropolymer having a polyfluoroalkyl group and having a unit containing an isocyanate group, and having 2 to 2 carbon atoms.
There may be mentioned a combination with a fluoropolymer having 20 polyfluoroalkyl groups and further having a unit containing a reactive group having activated hydrogen.

Among these low molecular weight fluoropolymers,
Use of tetrafluoroethylene polymer or fluoropolyether gives excellent results in lubricity,
In particular, it has been found that the use of a tetrafluoroethylene polymer having an average particle size of 5 μm or less gives the most desirable results.

In the present invention, the compounding ratio of the fluororubber and the thermoplastic fluororesin is preferably such that the weight ratio of the fluororubber and the thermoplastic fluororesin is 50:50 to 95: 5. The blending weight ratio of the thermoplastic fluororesin is 5
If it exceeds 0/100, sufficient elasticity cannot be obtained for the intended composition, and if it is less than 5/100, sufficient abrasion resistance cannot be obtained.

The low molecular weight fluoropolymer is preferably 5 to 50 parts by weight based on 100 parts by weight of the total of the fluororubber and the thermoplastic fluororesin. This is because if the compounding ratio of the low molecular weight fluoropolymer is less than 5 parts by weight, sufficient sliding properties cannot be obtained, and if it exceeds 50 parts by weight, the rubber-like elastic properties are impaired.

Further, with respect to the above-mentioned lubricating rubber composition, 3
Abrasion resistance can be improved by adding a cured powder of a thermosetting resin that does not melt at 00 ° C. or a heat-resistant resin powder having a glass transition point of 300 ° C. or higher.

As the thermosetting resin powder, fine powder after thermosetting such as phenol resin and epoxy resin, and as the heat resistant resin having a glass transition temperature of 300 ° C. or higher, polyimide resin, aromatic aramid resin, etc. Fine powder can be used.

Among the commercially available resin powders, the hardened and ground product of the phenol resin is Bellbell H300, manufactured by Kanebo Co., Ltd.
The hardened and ground product of the polyimide resin is manufactured by Mikasa Sangyo Co., Ltd .:
As a pulverized product of PWA20 and an aromatic aramid resin, Asahi Kasei Corporation: MP-P, and as a thermosetting resin powder having a glass transition point Tg of 300 ° C. or higher, Ube Industries: Upilex S (Tg> 500), etc. is there.

The particle size of such thermosetting resin powder is 1
Those having a particle size of up to 15 μm are preferable from the viewpoint of maintaining rubber-like elasticity and facilitating the kneading process. The thermosetting resin powder is preferably added in an amount of 5 to 20% by weight with respect to the first to third essential components. If it is less than 5% by weight, there is no effect of improving wear resistance and
If the amount is more than 10% by weight, the rubber elasticity decreases, which is not preferable.

In addition to the above components, various additives may be added within the range not impairing the object of the present invention. For example, as a vulcanizing agent for fluororubber, isocyanurate, organic peroxide, etc., antioxidants such as sodium stearate, magnesium oxide, and calcium hydroxide, or acid acceptors, antistatic agents such as carbon, silica and It goes without saying that fillers such as alumina, other metal oxides, colorants, flame retardants and the like may be added as appropriate.

The method for mixing the above various raw materials is not particularly limited, and the generally used methods can be used for mixing. For example, the elastomer as the main raw material and the other raw materials may be individually mixed sequentially or simultaneously by a roll mixer or other mixer. At this time, it is desirable to provide a temperature controller to prevent heat generation due to friction.

When a roll mixer is used,
For finishing mixing, it is more preferable to tighten the roll interval to about 3 mm or less and perform thin threading.

The wiper blade rubber according to the present invention comprises:
The molding step does not require a particularly limited means, and the primary vulcanization (for example, at 140 to 170 ° C. for 10 to 30 minutes and the pressure of 5 to 10 kgf is performed by a normal press molding method.
/ Cm ² ) and then secondary vulcanization (for example, 200 to 30).
It can be molded at 0 ° C. for 2 to 20 hours without applying pressure.

Further, only the sliding surface may be molded with the lubricating rubber composition containing the above-mentioned first to third essential components, and the other parts may be compounded with general synthetic rubber, plastic or metal.

Examples of the general synthetic rubber used at this time include vulcanized rubber such as nitrile rubber, chloroprene rubber, butadiene rubber, urethane rubber, styrene rubber, butyl rubber, acrylic rubber, silicone rubber, ethylene rubber, and fluororubber, or urethane, polyester. , Thermoplastic elastomers such as polyamide, vinyl chloride, polybutadiene, and soft nylon, and liquid elastomers such as liquid urethane and liquid butadiene.

[0050]

In the wiper blade rubber according to the present invention, at least the sliding surface is formed of a lubricating rubber composition, and the lubricating rubber composition is extremely excellent in wear resistance, low frictional characteristics and weather resistance. Therefore, unlike the conventional case, the stick-slip phenomenon or streaks does not occur, and the visibility is not obstructed.

[0051]

1 is a front view showing a wiper using a wiper blade rubber according to an embodiment of the present invention. Referring to FIG. 1, a wiper blade rubber 1 is supported by a wiper blade 2, and the wiper blade 2 is supported by an arm 3 to prepare a lubricating rubber composition used in the present invention. The properties were tested.

The raw materials used in Examples and Comparative Examples are collectively shown below. The mixing ratios of the respective components are all% by weight, but regarding the raw materials shown in (3) to (9), the total weight of the raw materials shown in (1) and (2) is 100.
% By weight.

(1) Vinylidene fluoride / fluoropropylene copolymer (Technoflon FOR42 manufactured by Asahi Monte Corporation)
0) (2) Tetrafluoroethylene / ethylene copolymer
(Aflon COP manufactured by Asahi Glass Co., Ltd.) (3) Low molecular weight fluoropolymer (low molecular weight TFE)
(Lubricant L169 manufactured by Asahi Glass Co., Ltd.) (4) Low molecular weight fluoropolymer (low molecular weight PFPE)
(Japan Anymont Fomblin Z-DISC
O) (5) Carbon (MT carbon manufactured by Van der Wirth) (6) Sodium stearate (general industrial material) (7) Magnesium oxide (general reagent) (8) Calcium hydroxide (general reagent) (9) Phenolic resin (Kanebo Belpearl H300) (10) Chloroprene rubber (CR)
(General industrial material hardness JIS-A-70) (11) Dimethyl silicone copolymer (silicon rubber)
(General industrial material hardness JIS-A-70)

[0054]

EXAMPLE First, a fluororubber (1) was wound around a roll mixer adjusted to a roll interval of about 5 to 10 mm, and MT carbon, sodium stearate, MgO, Ca (OH) ₂ were successively added at the ratios shown in Table 1. And kneaded. Then, the roll interval was adjusted to 1 mm, and mastication was performed about 10 times. For the purpose of preventing frictional heat at this time, cooling water was constantly passed through the roll to keep the roll temperature at 60 ° C or lower. Next, cooling water is stopped, steam is passed through the rolls, the rubber temperature is adjusted to 70 ° C or higher and 90 ° C or lower, and then the roll interval is returned to about 5 to 10 mm,
The low molecular weight fluorinated polymer was added little by little and kneaded at the compounding ratio of each example shown in Table 1. Then, the roll interval was again narrowed to 1 mm, and mastication was performed 10 times.

[0055]

[Table 1]

In the compound obtained in the above process, 150 × 150 × 1t sheet was subjected to primary vulcanization (170 ° C.,
10 minutes, press pressure 7 Kgf / cm ² ) secondary vulcanization (23
It was produced by carrying out 0 ° C, 16 hours, free). For each test piece, a friction test, an abrasion test, a non-stick property and an elastic body property were obtained. The method of each test is as follows.

(1) Test method-Friction and wear test The obtained test piece was processed into an inner diameter of 17 and an outer diameter of 21, and
A 7 × φ21 × 10 SPCC ring piece was bonded to give a ring test piece. Mating material is SUJ2 (bearing steel) φ6 × φ3
A 3 × φ6 disc-shaped test piece was used and evaluated using a thrust type friction and wear tester. The condition is a sliding speed of 128 m / min,
The surface pressure is 3.5 kgf / cm ² , and the friction coefficient and wear coefficient are shown in Table 2.

[0058]

[Table 2]

(2) Non-adhesion In the obtained test piece, the contact angle to water was measured by a goniometer-type contact angle measuring device, and it was judged that the larger the contact angle, the better the non-adhesiveness. The results are shown in Table 2.

(3) Elastic Body Properties The obtained test piece is compliant with JIS-K6301
The tensile strength, elongation and hardness (JIS-A) were investigated.
The results are shown in Table 2.

Comparative Example In the comparative example, the raw materials were blended in the proportions shown in Table 1, and kneading, molding and vulcanization were performed in the same manner as in the examples. The test pieces were adjusted and tested in exactly the same manner as in the examples. The results are shown in Table 2.

[Brief description of drawings]

FIG. 1 is a front view showing a wiper using a wiper blade rubber according to an embodiment of the present invention.

[Explanation of symbols]

 1 Wiper blade rubber 2 Wiper blade 3 Arm

Claims (7)

[Claims] 1. At least a sliding surface is formed of a lubricating rubber composition, and the lubricating rubber composition is a thermoplastic fluororesin which is a first essential component, a fluororubber which is a second essential component, and a third. A wiper blade rubber made of a low molecular weight fluoropolymer which is an essential component. 2. The wiper blade rubber according to claim 1, wherein a cured powder of a thermosetting resin or a heat-resistant resin powder having a glass transition point of 300 ° C. or higher is added to the lubricating rubber composition. 3. A group in which the thermoplastic fluororesin as the first essential component comprises a tetrafluoroethylene / ethylene copolymer, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. The wiper blade rubber according to claim 1, which is one or more selected from the following. 4. The second essential component has a molecular weight of 100,000 to 25.
The wiper blade rubber according to claim 1, which is a fluoro rubber. 5. A fluororubber as the second essential component is a tetrafluoroethylene / propylene copolymer, a vinylidene fluoride / hexafluoropropylene copolymer, a vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer, The wiper blade rubber according to claim 1, wherein the wiper blade rubber is one or more polymers selected from the group consisting of fluorosilicone elastomers and perfluoroelastomers. 6. The low molecular weight fluoropolymer as the third essential component is selected from the group consisting of tetrafluoroethylene polymers, fluoropolyethers and polyfluoroalkyl group-containing compounds which are polymers having a molecular weight of 50,000 or less. The wiper blade rubber according to claim 1, wherein the wiper blade rubber is one or more polymers. 7. The wiper blade rubber according to claim 1, wherein the low molecular weight fluoropolymer which is the third essential component is a tetrafluoroethylene polymer having an average particle size of 5 μm or less.