JP2015108079A - Sealing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing member which maintains sealing characteristics even after long-term use at a high temperature under pressure.SOLUTION: The sealing member contains a rubber component and a thermoplastic resin. The maximum value of the loss tangent of the sealing member in a temperature range of 20-150°C is less than 0.35. The rubber component contains at least one selected from the group consisting of natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, butyl rubber, urethane rubber, silicone rubber, chloroprene rubber, and acrylonitrile-butadiene rubber.

Description

  The present invention relates to a seal member.

  Seal members used in various fields including automobiles are required not only to have excellent seal characteristics but also to maintain the seal characteristics. For example, in the case of a seal member used in a hydraulic continuously variable transmission (CVT) of an automobile, it is required to withstand a maximum oil pressure of about 7 MPa generated in a hydraulic chamber. Further, considering that the CVT operates in a high temperature state, a seal member that maintains the sealing characteristics even when used for a long time under high temperature and pressure is required.

  An example of a seal member that can maintain the sealing characteristics is a seal ring made of a high resilience material having a low compression set. The highly repulsive material is composed of a polyvinyl chloride resin, polyurethane, and a plasticizer, and the polyurethane is obtained by a urethane reaction between a polymer polyol and a compound having three or more isocyanate groups. The highly repulsive material has a sea-island type phase separation structure observed with a transmission electron microscope, and the size of the phase separation structure is 0.01 μm or more and 100 μm or less (see Patent Document 1 below).

JP-A-7-173357

  The high resilience material disclosed in Patent Document 1 includes a polyvinyl chloride resin having a glass transition temperature near 87 ° C. as an essential component. For this reason, if the sealing member containing the above-mentioned high resilience material is pressurized at a temperature equal to or higher than the glass transition temperature, the sealing member is plastically deformed. Therefore, it has been difficult for the sealing member to maintain its sealing characteristics even after long-term use under high temperature and pressure.

  Then, an object of this invention is to provide the sealing member which maintains a sealing characteristic, even after using it for a long time under high temperature pressurization.

  The seal member according to one embodiment of the present invention contains a rubber component and a thermoplastic resin, and the maximum loss tangent of the seal member in a temperature range of 20 ° C. to 150 ° C. is less than 0.35, and the rubber component is , Natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene diene rubber, butyl rubber, urethane rubber, silicone rubber, chloroprene rubber and acrylonitrile-butadiene rubber Containing.

  The maximum value of the loss tangent may be 0.15 or less.

  The thermoplastic resin may contain at least one selected from the group consisting of polybutylene terephthalate, polyamide, polyphenylene sulfide, and polyvinylidene fluoride.

  The content of the rubber component may be larger than the content of the thermoplastic resin.

  The thermoplastic resin may be dispersed in the rubber component.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing member which can maintain a sealing characteristic after using it for a long time under high temperature pressurization can be provided.

It is a graph showing transition of the loss tangent by the temperature change of a part of Example and a comparative example.

  Hereinafter, an example of the form for implementing the sealing member of the present invention is explained. However, the present invention is not limited to the following embodiments.

  The seal member according to the present embodiment contains a rubber component and a thermoplastic resin.

(Rubber component)
The rubber component is added to the sealing member as a crosslinked rubber or a dynamic crosslinked resin. Examples of the crosslinked rubber include natural rubber, synthetic isoprene rubber (synthesized cis-1,4-polyisoprene, IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), and acrylonitrile-butadiene copolymer. What is necessary is just united rubber (NBR), butyl rubber, urethane rubber, silicone rubber, chloroprene rubber, etc. One of these cross-linked rubbers may be used, or a mixture of two or more cross-linked rubbers may be used. The crosslinked rubber may be used in combination with a dynamic crosslinked resin described later.

  The dynamically crosslinked resin has a structure in which a thermoplastic resin is dispersed in a crosslinked rubber phase. The thermoplastic resin used for the dynamically crosslinked resin is, for example, polyester or polyamide (PA). On the other hand, the crosslinked rubber phase is, for example, natural rubber, synthetic isoprene rubber, high cis polybutadiene, styrene-butadiene copolymer rubber, ethylene-propylene copolymer rubber (EPM), ethylene-propylene diene copolymer rubber (EPDM). Butyl rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, and the like. One of these rubbers may be used, or a mixture of two or more rubbers may be used.

  The dynamically crosslinked resin can be produced, for example, by melting and kneading an uncrosslinked rubber component to which a crosslinking agent has been added and a thermoplastic resin using a twin screw extruder. Thereby, dispersion and crosslinking of the rubber component and dispersion of the thermoplastic resin proceed simultaneously. Commercially available products may be used as the rubber component and the thermoplastic resin used in the dynamically crosslinked resin.

  The content of the rubber component is larger than the content of the thermoplastic resin. The content of the rubber component may be 60% by mass to 95% by mass, or 80% by mass to 95% by mass with respect to the mass of the entire sealing member. By setting the content of the rubber component within the above range, the compression set of the seal member is reduced. As a result, the seal member can maintain excellent rubber elasticity even after being used for a long time under pressurized conditions, so that the sealing characteristics can be maintained. Further, the surface hardness of the rubber component may be 60 to 90 in Shore hardness A (JIS K 6253).

(Thermoplastic resin)
Examples of the thermoplastic resin contained in the sealing member include polyester, polypropylene (PP), syndiotactic polystyrene resin, polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polyphenylene ether (PPE), and polyphenylene. Sulfide (PPS), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU), polyethersulfone, polyketone (PK), polyetherketone (PEK), polyetheretherketone ( PEEK), polyether ketone ketone (PEKK), polyarylate (PAR), polyether nitrile (PEN), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc. . The polyester may be polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), or the like. The thermoplastic resin may be a copolymer or a modified body. Moreover, 2 or more types of resin may be mixed among the above-mentioned thermoplastic resins. In consideration of injection moldability, heat resistance, and the like, the seal member only needs to contain at least one selected from the group consisting of PBT, PA, PPS, and PVDF.

  The content of the thermoplastic resin may be 5% by mass to 40% by mass with respect to the mass of the entire sealing member, and may be 5% by mass to 20% by mass. When the content of the thermoplastic resin is regulated within the above range, the mechanical strength and creep resistance of the seal member are improved. Moreover, since the sealing member can maintain excellent rubber elasticity even after being used for a long time under pressurized conditions, the sealing characteristics can be maintained. Thereby, even if it is an area | region where PV value is high, use of a sealing member is attained. The surface hardness of the thermoplastic resin contained in the sealing member is a Shore hardness D, which may be 70 or more, or 90 or more.

(Filler)
A filler may be added to the seal member depending on the use or required characteristics of the seal member. The filler may be, for example, an inorganic filler, an organic filler, a fibrous filler, or the like. One of these fillers may be used, or two or more fillers may be used.

  Examples of inorganic fillers include calcium carbonate, montmorillonite, bentonite, talc, silica, mica, mica, barium sulfate, calcium sulfate, calcium silicate, molybdenum disulfide, glass beads, aluminum oxide, titanium oxide, magnesium oxide, and potassium titanate. Boron nitride or the like may be used. The organic filler may be graphite, fullerene, carbon (amorphous) powder, anthracite powder or the like. By adding an inorganic filler or an organic filler to the seal member, the sliding characteristics and the like of the seal member are improved.

  The fibrous filler may be, for example, glass fiber, carbon fiber, carbon nanotube, alumina fiber, potassium titanate fiber, boron fiber, silicon carbide fiber, and the like. By adding a fibrous filler to the seal member, the mechanical strength and creep resistance of the seal member are improved. For this reason, excellent sealing characteristics can be maintained even after a long period of use under pressure. Thereby, even if it is an area | region where PV value is high, use of a sealing member is attained. Among the fibrous fillers, glass fibers, carbon fibers, or carbon nanotubes may be used. In particular, the carbon nanotube not only exhibits the above-described function as a fibrous filler, but also exhibits the function of improving the sliding characteristics of the seal member.

  The addition amount of the filler is, for example, 0% by mass to 10% by mass, 0% by mass to 5% by mass, 1% by mass to 10% by mass, and 1% by mass to 5% by mass with respect to the mass of the entire sealing member. It may be. Moreover, when adding a carbon nanotube to a sealing member, it is preferable that the addition amount of a carbon nanotube shall be 1 mass%-5 mass% with respect to the mass of the whole sealing member. By adding carbon nanotubes to the seal member within this range, a seal member having excellent mechanical strength and sliding characteristics can be obtained. Thereby, even after using a sealing member for a long time on pressurization conditions, a sealing member can maintain the outstanding sealing characteristic.

  The Shore hardness A of the sealing member may be 60 to 98, or 70 to 95. By defining the Shore hardness A of the seal member within this range, deformation of the seal member is suppressed. For this reason, high sealing performance is maintained even after long-time operation. Moreover, the mounting property when the sealing member is mounted on the shaft groove or the like is improved. The permanent compression strain of the seal member may be 98% or less, 70% or less, or 53% or less. When the permanent compression strain of the seal member is small, the seal member has excellent rubber elasticity. Thereby, the sealing performance of the sealing member is maintained.

  The maximum value (tan δ) max of the loss tangent (tan δ) of the seal member in the temperature range of 20 ° C. to 150 ° C. may be, for example, less than 0.35, 0.31 or less, and 0. It may be 15 or less. Further, the minimum value of tan δ of the sealing member in the temperature range of 20 ° C. to 150 ° C. may be 0.01 or more, may be 0.05 or more, and may be 0.11 or more. That is, (tan δ) max of the sealing member may be 0.11 or more and less than 0.35, may be 0.11 or more and 0.31 or less, and may be 0.11 or more and 0.15 or less. .

  tan δ is a ratio (E ″ / E ′) of loss elastic modulus (E ″) and storage elastic modulus (E ′) based on dynamic viscoelasticity measurement of the seal member. In general, the larger the tan δ of the seal member (ie, the greater the loss elastic modulus (E ″)), the easier the plastic member is deformed. Also, the smaller the tan δ of the seal member (ie, the storage modulus (E ′)). The larger the), the greater the repulsive force of the seal member, and the tan δ of the seal member usually varies with temperature.

  The (tan δ) max in the temperature range of 20 ° C. to 150 ° C. of the seal member according to the present embodiment is less than 0.35. Such a sealing member can maintain a high repulsive force even in a high temperature range (for example, 120 ° C. to 150 ° C.). In addition, since the seal member according to the present embodiment has (tan δ) max less than the above value, the compression set of the seal member is small even after high-temperature pressurization. For this reason, the seal member can maintain excellent rubber elasticity even after long-term use. Therefore, the sealing member can maintain the sealing characteristics over a long period of time even under severe use conditions. This effect is more remarkable as (tan δ) max is smaller. For example, when (tan δ) max is 0.15 or less, excellent sealing characteristics can be maintained over a long period of time.

  The (tan δ) max of the seal member in the above temperature range is controlled by the kind of thermoplastic resin contained in the seal member, the amount added, and the like. For example, when a thermoplastic resin having a glass transition temperature of 150 ° C. or higher is used, (tan δ) max can be lowered by reducing the content of the thermoplastic resin. Further, (tan δ) max can be lowered by highly dispersing the rubber component and the thermoplastic resin in the seal member. The method of highly dispersing the rubber component and the thermoplastic resin in the seal member is more advantageous than reducing the content of the thermoplastic resin in terms of injection moldability, mechanical strength, and creep resistance of the resin composition. is there.

(Method of mixing seal members)
The rubber component and the thermoplastic resin contained in the seal member are mixed using, for example, a lab plast mill, a twin screw extruder, or the like. In order to finely and uniformly disperse the rubber component and the thermoplastic resin, the rubber component and the thermoplastic resin are mixed under a high shear condition using a twin screw extruder in which a kneading disk that generates a shearing action is combined with the screw shaft. May be. Further, a high shear molding machine may be used. The dispersibility of the rubber component and the thermoplastic resin can be controlled by the shape and length of the screw, the feedback hole diameter, the screw rotation speed, the shear mixing time, and the like. A screw rotation speed may be 365-648 rpm, may be 415-648 rpm, may be 456-648 rpm, and may be 580-648 rpm.

  The rubber component and the thermoplastic resin in the seal member may be highly dispersed. The high dispersion of the rubber component and the thermoplastic resin suppresses an increase in tan δ of the thermoplastic resin near the glass transition temperature. Thereby, since the sealing member can maintain a high repulsive force even in a high temperature range, the sealing characteristics of the sealing member are maintained. Furthermore, since the plastic deformation of the seal member is suppressed even under high temperature and pressure, the seal characteristics of the seal member are maintained over a long period of time.

  The thermoplastic resin in the sealing member may be dispersed in the rubber component. Thereby, the plastic deformation of the seal member due to the high flow of the thermoplastic resin in the vicinity of the glass transition temperature can be suppressed by the surrounding rubber component. Therefore, an increase in tan δ of the seal member can be suppressed.

  The rubber component in the seal member does not contain fluorine. When fluorine is contained in the rubber component, the compatibility between the rubber component and the thermoplastic resin is deteriorated. Thereby, the thermoplastic resin is not highly dispersed, and the tan δ of the thermoplastic resin near the glass transition temperature is increased.

The size (particle size or equivalent circle diameter) of the thermoplastic resin dispersed in the rubber component may be 40 nm to 100 nm. Regarding the size of the thermoplastic resin, first, a photograph of a sample prepared by the RuO ₄ stained ultrathin section method is taken with a transmission electron microscope (TEM). By specifying the thermoplastic resin from this photograph and measuring the diameter of the thermoplastic resin, the size of the thermoplastic resin can be calculated.

  The seal member may be, for example, a rotational motion seal ring, a reciprocating motion seal ring, or the like, or a seal ring mounted on a CVT of an automobile.

  When the seal member is used as a CVT seal ring, an endless type seal ring having no joint may be employed in order to reliably prevent oil leakage when the seal ring is in a no-load state. The single endless seal ring is easy to install. On the other hand, depending on the use of the seal ring and the like, an abutment may be provided in the seal ring. The shape of the joint in this case may be, for example, a right angle (straight) joint, an oblique (angle) joint, a stepped joint, a double angle joint, a double cut joint, a triple step joint, or the like.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1
Natural rubber was used as the rubber component, and polyvinylidene fluoride resin was used as the thermoplastic resin. The mass ratio of the rubber component and the thermoplastic resin (rubber component: thermoplastic resin) was adjusted to 90:10, and supplied to the twin-screw extruder by the side feeder. The rubber component and the thermoplastic resin were mixed using a twin-screw extruder under a shearing condition of a temperature of 240 ° C. and a constant screw rotation speed to produce pellets. The twin screw extruder was provided with a φ92 mm screw combined with a lead and a kneading disk. Table 1 shows the screw rotation speed.

(Example 2)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was synthesized cis-1,4-polyisoprene and the screw rotation speed during mixing was changed.

(Example 3)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was high-cis polybutadiene and the screw rotation speed during mixing was changed.

Example 4
Pellets were produced under the same conditions as in Example 1 except that the rubber component was styrene-butadiene rubber and the screw rotation speed during mixing was changed.

(Example 5)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was acrylonitrile-butadiene rubber and the screw rotation speed during mixing was changed.

(Example 6)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was butyl rubber and the screw rotation speed during mixing was changed.

(Example 7)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was urethane rubber and the screw rotation speed during mixing was changed.

(Example 8)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was silicone rubber and the screw rotation speed during mixing was changed.

Example 9
Pellets were produced under the same conditions as in Example 1 except that the rubber component was natural rubber and synthesized cis-1,4-polyisoprene, and the screw rotation speed during mixing was changed.

(Example 10)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was high-cis polybutadiene and butyl rubber, and the screw rotation speed during mixing was changed.

(Example 11)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was butyl rubber and silicone rubber, and the screw rotation speed during mixing was changed.

(Example 12)
Pellets were produced under the same conditions as in Example 1 except that the rubber component was chloroprene rubber and the screw rotation speed during mixing was changed.

(Comparative Example 1)
Pellets were produced under the same conditions as in Example 4 except that the screw rotation speed was changed.

(Comparative Example 2)
Pellets were produced under the same conditions as in Example 9 except that the screw rotation speed was changed.

(Measurement of loss tangent (tan δ) max in dynamic viscoelasticity)
The pellets of Examples 1 to 12 and Comparative Examples 1 and 2 were hot pressed to produce sheets having a thickness of 500 μm to 1000 μm. By cutting this sheet, a strip-shaped sample having a width of 3 mm and a length of 20 mm was produced. A thermomechanical analyzer (manufactured by SII Nanotechnology Inc.) was used as a dynamic viscoelasticity measuring device. Dynamic storage elastic modulus (E ′) and dynamic loss elastic modulus (E ″) of each strip-shaped sample at 20 ° C. to 150 ° C. under the conditions of a measurement frequency of 0.1 Hz and a heating rate of 3 ° C./min in air. From the results of the dynamic storage modulus (E ′) and the dynamic loss modulus (E ″) at each measurement temperature, the loss tangent (tan δ) in Examples 1 to 12 and Comparative Examples 1 and 2 was measured. = (E ″) / (E ′)), (tan δ) max, was measured. The measurement results of (tan δ) max of each strip sample are shown in Table 1, and each measurement of each strip sample The tan δ at the temperature is shown in Table 2. Further, the results of calculating the loss tangent at each measurement temperature in the strip samples of Examples 4 and 9 and Comparative Examples 1 and 2 were plotted as shown in FIG.

(Measurement of surface hardness)
Based on JIS K7215, the Shore hardness of each pellet of Examples 1-12 and Comparative Examples 1 and 2 was measured. The measurement results of these Shore hardnesses are shown in Table 1.

(Measurement of compression set)
The compression set Cs was measured as follows with reference to JIS K6262. Specifically, test pieces of 5 mm × 15 mm and a thickness of 2 mm were produced by injection molding of the pellets of Examples 1 to 12 and Comparative Examples 1 and 2. The thickness of the center part of the injected test piece is (t ₀ ). The test piece was attached to a compression device, and the test piece was compressed until the compression amount became 25%. The test piece attached to the compression apparatus was immersed in a lubricating oil (Automatic Transmission Fluid: ATF) adjusted to 150 ° C. for 100 hours. After the immersion, the compression device and the test piece were taken out from the ATF. And the test piece was removed from the compression apparatus. After wiping off the ATF adhering to the removed test piece, the test piece was allowed to stand at room temperature for 30 minutes. The thickness of the central portion of the test piece after standing (t ₁₎ was measured. When the thickness of the spacer disposed between the compression plates of the compression device based on JIS K6262 is (t ₂ ), the compression set Cs of each test piece was calculated by the following equation (1). Table 1 shows the measurement results of these compression set Cs.
Cs = (t ₀ -t ₁ ) / (t ₀ -t ₂ ) × 100 (1)
t ₀ : Original thickness of the test piece (mm)
t ₁ : Thickness after standing 30 minutes (mm)
t ₂ : Spacer thickness (mm)

(Measurement of oil leakage in a stationary state)
Seal rings having no joints were produced by injection molding of the pellets of Examples 1 to 12 and Comparative Examples 1 and 2. The size of the seal ring was set so that the compression amount was 25% in a state where the seal ring was mounted in the shaft groove of the static leakage performance test apparatus. The obtained seal ring was attached to a shaft groove provided on the outer peripheral surface of the shaft of the test apparatus. Next, ATF was filled in the hydraulic chamber of the static leakage performance test apparatus. The temperature of the ATF was 25 ° C., and the static leakage performance test apparatus was allowed to stand at room temperature for 7 days. The ATF that leaked from the hydraulic chamber while the static leakage performance test apparatus was left standing was collected from the oil drain groove. Table 1 shows the amount of ATF recovered from the oil drain groove as the amount of static oil leakage before operation.

  Next, the housing installed around the axis was reciprocated for a cumulative 1 km at a stroke of 10 mm / s. The hydraulic pressure during reciprocation of the housing was set to 4.0 MPa, and the ATF temperature was set to 150 ° C. After the reciprocation of the housing was completed, ATF leaked from the hydraulic chamber was recovered again by the same method. The amount of ATF recovered is shown in Table 1 as the amount of static oil leakage after operation.

  From Table 1, it is confirmed that (tan δ) max in the temperature range of 20 ° C. to 150 ° C. is less than 0.35, so that the seal characteristics of the seal member are maintained even after long-term use under high temperature and pressure. It was done. Further, the compression set of Comparative Examples 1 and 2 was 100%, whereas the compression set of Examples 1 to 12 was smaller than 100%. Thereby, it was confirmed that the sealing member produced using the pellets of Examples 1 to 12 maintained better rubber elasticity than the sealing member produced using the pellets of Comparative Examples 1 and 2. .

  From Table 1, in Comparative Example 1 and Comparative Example 2, the amount of static oil leakage before operation was 56 ml or more. On the other hand, in Examples 1-7 and 11-12, the amount of static oil leakage before operation was 0 ml. In Examples 8 to 10, the amount of static oil leakage before operation was 5 ml or less. Therefore, the static oil leakage amount before operation of Examples 1 to 12 was very small as compared with the static oil leakage amount before operation of Comparative Example 1 and Comparative Example 2.

  Moreover, in the comparative example 1 and the comparative example 2, the static oil leak amount after a driving | operation was 220 ml or more. On the other hand, in Examples 1-4, 8-10, and 12, the static oil leakage after operation was 58 ml or less. Moreover, in Examples 5-7 and 11, even after the operation, the static oil leakage amount was 0 ml. Therefore, the amount of static oil leakage after operation of Examples 1 to 12 was very small compared to the amount of static oil leakage after operation of Comparative Example 1 and Comparative Example 2.

  The same material was used in Example 4 and Comparative Example 1. In addition, Example 9 and Comparative Example 2 used the same material. However, as shown in FIG. 1, the calculation results of tan δ were greatly different. The difference in tan δ was due to the difference in the number of screw rotations when mixing the rubber component and the thermoplastic resin. By adjusting the screw rotation speed at the time of mixing, the thermoplastic resin is highly dispersed in the rubber component. Thereby, since Example 4 and Example 9 reduce (tan-delta) max and compression set lower compared with the comparative example 1 and the comparative example 2, the static oil leakage amount before driving | running and after driving | running | working It was confirmed that the amount of static oil leakage was significantly reduced.

  Further, the thermoplastic resin is changed from polyvinylidene fluoride to polybutylene terephthalate, polyamide, or polyphenylene sulfide, and the same rubber component as in Example 4 or Example 9 is used to adjust the screw rotation speed, respectively (tan δ) Twenty-four seal members with max of 0.25, 0.35, 0.15, or 0.4 were created. Even when these seal members were used, the amount of static leakage after operation was similar to that in Examples using poly (vinylidene fluoride) as a thermoplastic resin.

  It was confirmed that the compression set of Examples 5 to 7 and 11 in which the amount of static oil leakage after operation was 0 ml was significantly reduced as compared with the other examples. In addition, it was confirmed that the (tan δ) max of Examples 5 to 7 and 11 was 0.15 or less by adjusting the rubber material and the screw rotation speed. From the above, the rubber elasticity is improved by reducing the compression set. Therefore, since (tan δ) max decreases, it was confirmed that the sealing characteristics were maintained even after operating under high temperature and pressure.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing member which can maintain a sealing characteristic even after using it for a long time under high temperature pressurization is provided.

The seal member according to one embodiment of the present invention contains a rubber component and a thermoplastic resin, and the maximum loss tangent of the seal member in a temperature range of 20 ° C. to 150 ° C. is less than 0.35, and the rubber component is , Bed Tajiengomu, styrene - butadiene rubbers, ethylene - propylene rubbers, ethylene - propylene diene rubber, butyl rubber, urethane rubber, click Roropurengomu and acrylonitrile - containing at least one selected from the group consisting of butadiene rubber, thermoplastic resins, poly It contains at least one selected from the group consisting of butylene terephthalate, polyamide, polyphenylene sulfide, and polyvinylidene fluoride .

(Rubber component)
The rubber component is added to the sealing member as a crosslinked rubber or a dynamic crosslinked resin. Crosslinked rubber, for example, blanking Tajiengomu (BR), styrene - butadiene copolymer rubber (SBR), acrylonitrile - butadiene copolymer rubber (NBR), butyl rubber, urethane rubber, Ru der like click Roropurengomu. One of these cross-linked rubbers may be used, or a mixture of two or more cross-linked rubbers may be used. The crosslinked rubber may be used in combination with a dynamic crosslinked resin described later.

The dynamically crosslinked resin has a structure in which a thermoplastic resin is dispersed in a crosslinked rubber phase. The thermoplastic resin used for the dynamically crosslinked resin is, for example, polyester or polyamide (PA). On the other hand, cross-linked rubber phase, for example, Ha Isis polybutadiene, styrene - butadiene copolymer rubber, ethylene - propylene copolymer rubber (EPM), ethylene - propylene diene copolymer rubber (EPDM), butyl rubber, acrylonitrile - butadiene copolymer polymer rubber, Ru der chloroprene rubber. One of these rubbers may be used, or a mixture of two or more rubbers may be used.

(Thermoplastic resin)
Thermoplastic resin contained in the sealing member, for example, polyesters, polyamides (PA), port riff two sulfide (PPS), Po Rifu' fluoride (PVDF) Ru Hitoshidea. Polyester, Ru Oh in the port polybutylene terephthalate (PBT). The thermoplastic resin may be a copolymer or a modified body. Moreover, 2 or more types of resin may be mixed among the above-mentioned thermoplastic resins. In consideration of injection moldability, heat resistance, and the like, the seal member only needs to contain at least one selected from the group consisting of PBT, PA, PPS, and PVDF.

( Reference Example 1)
Natural rubber was used as the rubber component, and polyvinylidene fluoride resin was used as the thermoplastic resin. The mass ratio of the rubber component and the thermoplastic resin (rubber component: thermoplastic resin) was adjusted to 90:10, and supplied to the twin-screw extruder by the side feeder. The rubber component and the thermoplastic resin were mixed using a twin-screw extruder under a shearing condition of a temperature of 240 ° C. and a constant screw rotation speed to produce pellets. The twin screw extruder was provided with a φ92 mm screw combined with a lead and a kneading disk. Table 1 shows the screw rotation speed.

( Reference Example 2)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was synthesized cis-1,4-polyisoprene and the screw rotation speed during mixing was changed.

(Example 3)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was high-cis polybutadiene and the screw rotation speed during mixing was changed.

Example 4
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was styrene-butadiene rubber and the screw rotation speed during mixing was changed.

(Example 5)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was acrylonitrile-butadiene rubber and the screw rotation speed during mixing was changed.

(Example 6)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was butyl rubber and the screw rotation speed during mixing was changed.

(Example 7)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was urethane rubber and the screw rotation speed during mixing was changed.

( Reference Example 8)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was silicone rubber and the screw rotation speed during mixing was changed.

( Reference Example 9)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was natural rubber and synthesized cis-1,4-polyisoprene, and the screw rotation speed during mixing was changed.

(Example 10)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was high cis polybutadiene and butyl rubber, and the screw rotation speed during mixing was changed.

(Example 11)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was butyl rubber and silicone rubber, and the screw rotation speed during mixing was changed.

(Example 12)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was chloroprene rubber and the screw rotation speed during mixing was changed.

(Comparative Example 2)
Pellets were produced under the same conditions as in Reference Example 9 except that the screw rotation speed was changed.

(Measurement of loss tangent (tan δ) max in dynamic viscoelasticity)
Each of the pellets of Examples 3 to 7, 10 to 12, Reference Examples 1, 2, 8, and 9 and Comparative Examples 1 and 2 was hot pressed to produce a sheet having a thickness of 500 μm to 1000 μm. By cutting this sheet, a strip-shaped sample having a width of 3 mm and a length of 20 mm was produced. A thermomechanical analyzer (manufactured by SII Nanotechnology Inc.) was used as a dynamic viscoelasticity measuring device. Dynamic storage elastic modulus (E ′) and dynamic loss elastic modulus (E ″) of each strip-shaped sample at 20 ° C. to 150 ° C. under the conditions of a measurement frequency of 0.1 Hz and a heating rate of 3 ° C./min in air. From the results of the dynamic storage elastic modulus (E ′) and the dynamic loss elastic modulus (E ″) at each measurement temperature, Examples 3 to 7, 10 to 12, Reference Examples 1, 2, and 8 , 9, and Comparative Examples 1 and 2, (tan δ) max, which is the maximum value of the loss tangent (tan δ = (E ″) / (E ′)), was measured. (Tan δ) max of each strip-shaped sample was measured. The results are shown in Table 1, and the tan δ at each measurement temperature of each strip sample is shown in Table 2. Also, the measurement samples for each measurement temperature in the strip samples of Example 4 , Reference Example 9 and Comparative Examples 1 and 2 are shown. The results of calculating the loss tangent were plotted as shown in FIG.

(Measurement of surface hardness)
Based on JIS K7215, the Shore hardness of each pellet of Examples 3 to 7, 10 to 12, Reference Examples 1, 2, 8, and 9 and Comparative Examples 1 and 2 was measured. The measurement results of these Shore hardnesses are shown in Table 1.

(Measurement of compression set)
The compression set Cs was measured as follows with reference to JIS K6262. Specifically, a test piece of 5 mm × 15 mm and a thickness of 2 mm was obtained by injection molding of each pellet of Examples 3 to 7, 10 to 12, Reference Examples 1, 2, 8, 9 and Comparative Examples 1 and 2. Produced. The thickness of the center part of the injected test piece is (t ₀ ). The test piece was attached to a compression device, and the test piece was compressed until the compression amount became 25%. The test piece attached to the compression apparatus was immersed in a lubricating oil (Automatic Transmission Fluid: ATF) adjusted to 150 ° C. for 100 hours. After the immersion, the compression device and the test piece were taken out from the ATF. And the test piece was removed from the compression apparatus. After wiping off the ATF adhering to the removed test piece, the test piece was allowed to stand at room temperature for 30 minutes. The thickness of the central portion of the test piece after standing (t ₁₎ was measured. When the thickness of the spacer disposed between the compression plates of the compression device based on JIS K6262 is (t ₂ ), the compression set Cs of each test piece was calculated by the following equation (1). Table 1 shows the measurement results of these compression set Cs.
Cs = (t ₀ -t ₁ ) / (t ₀ -t ₂ ) × 100 (1)
t ₀ : Original thickness of the test piece (mm)
t ₁ : Thickness after standing 30 minutes (mm)
t ₂ : Spacer thickness (mm)

(Measurement of oil leakage in a stationary state)
Seal rings having no joints were produced by injection molding of the pellets of Examples 3 to 7, 10 to 12, Reference Examples 1, 2, 8, and 9 and Comparative Examples 1 and 2. The size of the seal ring was set so that the compression amount was 25% in a state where the seal ring was mounted in the shaft groove of the static leakage performance test apparatus. The obtained seal ring was attached to a shaft groove provided on the outer peripheral surface of the shaft of the test apparatus. Next, ATF was filled in the hydraulic chamber of the static leakage performance test apparatus. The temperature of the ATF was 25 ° C., and the static leakage performance test apparatus was allowed to stand at room temperature for 7 days. The ATF that leaked from the hydraulic chamber while the static leakage performance test apparatus was left standing was collected from the oil drain groove. Table 1 shows the amount of ATF recovered from the oil drain groove as the amount of static oil leakage before operation.

From Table 1, it is confirmed that (tan δ) max in the temperature range of 20 ° C. to 150 ° C. is less than 0.35, so that the seal characteristics of the seal member are maintained even after long-term use under high temperature and pressure. It was done. Further, while the compression set of Comparative Example 1 and Comparative Example 2 was 100%, the compression set of Examples 3 to 7, 10 to 12 and Reference Examples 1 , 2 , 8, and 9 was 100%. %. Thereby, the seal member produced using the pellets of Examples 3 to 7, 10 to 12 and Reference Examples 1 , 2 , 8, and 9 was produced using the pellets of Comparative Examples 1 and 2. It was confirmed that excellent rubber elasticity was maintained.

From Table 1, in Comparative Example 1 and Comparative Example 2, the amount of static oil leakage before operation was 56 ml or more. On the other hand, in Examples 3 to 7 and 11 to 12 and Reference Examples 1 and 2 , the static oil leakage amount before operation was 0 ml. In Example 10 and Reference Examples 8 and 9 , the static oil leakage before operation was 5 ml or less. Therefore, the static oil leakage amount before the operation of Examples 3 to 7, 10 to 12, and Reference Examples 1 , 2 , 8, and 9 is the static oil leakage amount before the operation of Comparative Example 1 and Comparative Example 2. Compared to very few.

Moreover, in the comparative example 1 and the comparative example 2, the static oil leak amount after a driving | operation was 220 ml or more. On the other hand, in Examples 3, 4 , 10 and 12 , and Reference Examples 1 , 2, 8 , and 9 , the static oil leakage after operation was 58 ml or less. Moreover, in Examples 5-7 and 11, even after the operation, the static oil leakage amount was 0 ml. Therefore, the static oil leakage after operation of Examples 3 to 7, 10 to 12, and Reference Examples 1 , 2 , 8, and 9 is the static oil leakage after operation of Comparative Example 1 and Comparative Example 2. Compared to very few.

The same material was used in Example 4 and Comparative Example 1. Reference Example 9 and Comparative Example 2 used the same material. However, as shown in FIG. 1, the calculation results of tan δ were greatly different. The difference in tan δ was due to the difference in the number of screw rotations when mixing the rubber component and the thermoplastic resin. By adjusting the screw rotation speed at the time of mixing, the thermoplastic resin is highly dispersed in the rubber component. Thus, in Example 4 and Reference Example 9, (tan δ) max is reduced and compression set is reduced compared to Comparative Example 1 and Comparative Example 2, so that the static oil leakage amount before operation and after operation It was confirmed that the amount of static oil leakage was significantly reduced.

Further, the thermoplastic resin is changed from polyvinylidene fluoride to polybutylene terephthalate, polyamide, or polyphenylene sulfide, and the same rubber component as in Example 4 or Reference Example 9 is used to adjust the screw rotation speed, respectively (tan δ). Twenty-four seal members with max of 0.25, 0.35, 0.15, or 0.4 were created. Even when these seal members were used, the amount of static leakage after operation was similar to that in Examples or Reference Examples using poly (vinylidene fluoride) as a thermoplastic resin.

The seal member according to one embodiment of the present invention contains a rubber component and a thermoplastic resin, and the maximum loss tangent of the seal member in a temperature range of 20 ° C. to 150 ° C. is less than 0.35, and the rubber component is , butadiene rubber, styrene - butadiene rubbers, ethylene - propylene rubbers, ethylene - propylene diene rubber, butyl rubber, urethane rubber, and at least one contains a thermoplastic resin selected from chloroprene rubber or Ranaru group, positive Rifu' of vinylidene.

(Rubber component)
The rubber component is added to the sealing member as a crosslinked rubber or a dynamic crosslinked resin. Crosslinked rubbers, such as butadiene rubber (BR), styrene - butadiene copolymer rubber (SBR), blanking Chirugomu, urethane rubber, Ru der chloroprene rubber. One of these cross-linked rubbers may be used, or a mixture of two or more cross-linked rubbers may be used. The crosslinked rubber may be used in combination with a dynamic crosslinked resin described later.

The dynamically crosslinked resin has a structure in which a thermoplastic resin is dispersed in a crosslinked rubber phase. The thermoplastic resin used for the dynamically crosslinked resin is, for example, polyester or polyamide (PA). On the other hand, cross-linked rubber phase, for example, high cis-polybutadiene, styrene - butadiene copolymer rubber, ethylene - propylene copolymer rubber (EPM), ethylene - propylene diene copolymer rubber (EPDM), butyl rubber, with click Roropurengomu etc. is there. One of these rubbers may be used, or a mixture of two or more rubbers may be used.

(Thermoplastic resin)
Thermoplastic resin contained in the sealing member is po Rifu' fluoride (PVDF). The thermoplastic resin may be a copolymer or a modified body . When y de consideration of moldability and heat resistance, the seal member has only to contain P VDF.

( Reference Example 5)
Pellets were produced under the same conditions as in Reference Example 1 except that the rubber component was acrylonitrile-butadiene rubber and the screw rotation speed during mixing was changed.

(Measurement of loss tangent (tan δ) max in dynamic viscoelasticity)
Each of the pellets of Examples 3 , 4, 6, 7 , 10-12, Reference Examples 1, 2, 5, 8, 9 and Comparative Examples 1 and 2 is hot-pressed and has a thickness of 500 μm to 1000 μm. Was made. By cutting this sheet, a strip-shaped sample having a width of 3 mm and a length of 20 mm was produced. A thermomechanical analyzer (manufactured by SII Nanotechnology Inc.) was used as a dynamic viscoelasticity measuring device. Dynamic storage elastic modulus (E ′) and dynamic loss elastic modulus (E ″) of each strip-shaped sample at 20 ° C. to 150 ° C. under the conditions of a measurement frequency of 0.1 Hz and a heating rate of 3 ° C./min in air. From the results of dynamic storage elastic modulus (E ′) and dynamic loss elastic modulus (E ″) at each measurement temperature, Examples 3 , 4, 6, 7, 10-12, and Reference Example 1 , 2, 5, 8 , 9 and Comparative Examples 1 and 2, the maximum value (tan δ) max of the loss tangent (tan δ = (E ″) / (E ′)) was measured. The measurement results of (tan δ) max are shown in Table 1, and tan δ at each measurement temperature of each strip-shaped sample is shown in Table 2. Also, strip shapes for Example 4, Reference Example 9 and Comparative Examples 1 and 2 The result of calculating the loss tangent for each measured temperature in the sample was plotted as shown in FIG.

(Measurement of surface hardness)
Based on JIS K7215, the Shore hardness of each pellet of Examples 3 , 4, 6, 7 , 10-12, Reference Examples 1, 2, 5, 8, 9 and Comparative Examples 1 and 2 was measured. The measurement results of these Shore hardnesses are shown in Table 1.

(Measurement of compression set)
The compression set Cs was measured as follows with reference to JIS K6262. Specifically, by injection molding of each pellet of Examples 3 , 4, 6, 7 , 10-12, Reference Examples 1, 2, 5, 8, 9 and Comparative Examples 1 and 2, 5 mm × 15 mm, thickness A test piece having a thickness of 2 mm was prepared. The thickness of the center part of the injected test piece is (t ₀ ). The test piece was attached to a compression device, and the test piece was compressed until the compression amount became 25%. The test piece attached to the compression apparatus was immersed in a lubricating oil (Automatic Transmission Fluid: ATF) adjusted to 150 ° C. for 100 hours. After the immersion, the compression device and the test piece were taken out from the ATF. And the test piece was removed from the compression apparatus. After wiping off the ATF adhering to the removed test piece, the test piece was allowed to stand at room temperature for 30 minutes. The thickness of the central portion of the test piece after standing (t ₁₎ was measured. When the thickness of the spacer disposed between the compression plates of the compression device based on JIS K6262 is (t ₂ ), the compression set Cs of each test piece was calculated by the following equation (1). Table 1 shows the measurement results of these compression set Cs.
Cs = (t ₀ -t ₁ ) / (t ₀ -t ₂ ) × 100 (1)
t ₀ : Original thickness of the test piece (mm)
t ₁ : Thickness after standing 30 minutes (mm)
t ₂ : Spacer thickness (mm)

(Measurement of oil leakage in a stationary state)
Seal rings having no joints were produced by injection molding of the pellets of Examples 3 , 4, 6, 7 , 10-12, Reference Examples 1, 2, 5, 8, 9, and Comparative Examples 1 and 2. The size of the seal ring was set so that the compression amount was 25% in a state where the seal ring was mounted in the shaft groove of the static leakage performance test apparatus. The obtained seal ring was attached to a shaft groove provided on the outer peripheral surface of the shaft of the test apparatus. Next, ATF was filled in the hydraulic chamber of the static leakage performance test apparatus. The temperature of the ATF was 25 ° C., and the static leakage performance test apparatus was allowed to stand at room temperature for 7 days. The ATF that leaked from the hydraulic chamber while the static leakage performance test apparatus was left standing was collected from the oil drain groove. Table 1 shows the amount of ATF recovered from the oil drain groove as the amount of static oil leakage before operation.

From Table 1, it is confirmed that (tan δ) max in the temperature range of 20 ° C. to 150 ° C. is less than 0.35, so that the seal characteristics of the seal member are maintained even after long-term use under high temperature and pressure. It was done. Moreover, while the compression set of Comparative Example 1 and Comparative Example 2 was 100%, Examples 3 , 4, 6, 7, 10-12, and Reference Examples 1, 2, 5, 8 , 9 The compression set was less than 100%. Thereby, the sealing member produced using the pellets of Examples 3 , 4, 6, 7 , 10-12 and Reference Examples 1, 2, 5, 8 , 9 uses the pellets of Comparative Examples 1 and 2. It was confirmed that the rubber elasticity superior to that of the sealing member produced in this way was maintained.

From Table 1, in Comparative Example 1 and Comparative Example 2, the amount of static oil leakage before operation was 56 ml or more. On the other hand, in Examples 3 , 4, 6, 7, 11 to 12 and Reference Examples 1 and 2, the amount of static oil leakage before operation was 0 ml. In Example 10 and Reference Examples 8 and 9, the static oil leakage before operation was 5 ml or less. Therefore, the static oil leakage amount before the operation of Examples 3 , 4, 6, 7, 10 to 12 and Reference Examples 1, 2, 5, 8, and 9 is the same as that before the operation of Comparative Example 1 and Comparative Example 2. The amount of static oil leakage was very small.

Moreover, in the comparative example 1 and the comparative example 2, the static oil leak amount after a driving | operation was 220 ml or more. On the other hand, in Examples 3, 4, 10, and 12 and Reference Examples 1, 2, 8, and 9, the static oil leakage after operation was 58 ml or less. Further, in Examples 6, 7 and 11 and Reference Example 5 , the static oil leakage amount was 0 ml even after operation. Therefore, the amount of static oil leakage after the operation of Examples 3 , 4, 6, 7 , 10-12 and Reference Examples 1, 2, 5, 8 , 9 is the same as that after the operation of Comparative Example 1 and Comparative Example 2. The amount of static oil leakage was very small.

It was confirmed that the compression set of Examples 6, 7 and 11 and Reference Example 5 in which the amount of static oil leakage after operation was 0 ml was significantly reduced as compared with the other examples. It was done. In addition, it was confirmed that (tan δ) max of Examples 6, 7 and 11 and Reference Example 5 was 0.15 or less by adjusting the rubber material and the screw rotation speed. From the above, the rubber elasticity is improved by reducing the compression set. Therefore, since (tan δ) max decreases, it was confirmed that the sealing characteristics were maintained even after operating under high temperature and pressure.

Claims (5)

A sealing member containing a rubber component and a thermoplastic resin,
The maximum value of the loss tangent of the seal member in the temperature range of 20 ° C. to 150 ° C. is less than 0.35,
The rubber component is from the group consisting of natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene diene rubber, butyl rubber, urethane rubber, silicone rubber, chloroprene rubber and acrylonitrile-butadiene rubber. A seal member containing at least one selected.   The sealing member according to claim 1, wherein a maximum value of the loss tangent is 0.15 or less.   The sealing member according to claim 1 or 2, wherein the thermoplastic resin contains at least one selected from the group consisting of polybutylene terephthalate, polyamide, polyphenylene sulfide, and polyvinylidene fluoride.   The seal member according to any one of claims 1 to 3, wherein a content of the rubber component is larger than a content of the thermoplastic resin.   The seal member according to claim 4, wherein the thermoplastic resin is dispersed in the rubber component.

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