Blade rubber, wiper blade, and wiper device

Abstract

To provide a blade rubber having high sweeping performance through durable use, by suppressing hardness change due to moisture absorption against environmental change at the time of use.SOLUTION: A blade rubber comprises an elastic member containing polyurethane elastomer, in which a portion of the elastic member is brought into contact with the surface of a member to be cleaned to clean the surface of the member to be cleaned. A storage modulus E' of the blade rubber at a vibration frequency of 1×10-3 Hz in a 24°C environment is 12.0 to 18.0 MPa, and in a pulse NMR measurement at 50°C environment on a sample taken from the blade rubber, there exists a segment with a spin-spin relaxation time (T2L) of 250 to 360 μs, the polyurethane elastomer includes a specific polysiloxane segment, and the polysiloxane segment is bonded to a structure including the polyurethane backbone in the polyurethane elastomer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a blade rubber, wiper blade, and wiper device containing a polyurethane elastomer for wiping the surface of a windshield of a vehicle or the surface of a protective glass of a lens device or imaging device such as a network camera. [Background technology]

[0002] BACKGROUND ART It is known that a wiper device is used outdoors to wipe away rain, water droplets, dirt, etc. adhering to various surfaces to be wiped by moving in close contact with the surface to be wiped, thereby ensuring visibility.

[0003] Wiper devices are used to ensure visibility in various transport and moving vehicles such as automobiles, trains, ships, and aircraft, and to wipe the surfaces of lens devices and protective glass of network cameras installed outdoors. Wiper devices are known that have wiper blades that include rubber in the portion that contacts the surface to be wiped. It is desirable for wiper blades to be able to adhere closely to the surface to be wiped, sufficiently wipe away water droplets adhering to the surface, and sufficiently scrape off dirt and other particles adhering to the surface to be wiped, in both high-humidity and low-humidity environments. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-024375 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-186366 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 discloses a rubber blade for a process cartridge and an image-forming device, which has a surface layer containing a siloxane compound made of a cured product of a curable composition in the portion that contacts the surface to be wiped. The surface layer containing siloxane reduces the coefficient of friction of the blade, reduces frictional force during sliding, suppresses blade wear, and also stabilizes the behavior of the tip of the blade during sliding. However, according to the inventors' investigations, in the wiper blade rubber disclosed in Patent Document 1, the siloxane compound in the rubber is not chemically bonded to the rubber, allowing the siloxane compound to move freely within the rubber. As a result, there are areas in the rubber where the siloxane compound is unevenly distributed, making it impossible to prevent moisture from penetrating into the rubber in high-humidity environments. As a result, swelling can cause a decrease in hardness, and the contact width with the wiping surface can increase, reducing the contact pressure and resulting in poor wiping performance.

[0006] Patent Document 2 discloses an electronic copier cleaning blade made of a urethane polymer containing an organopolysiloxane having a reactive group at one end. Unlike Patent Document 1, the siloxane is chemically bonded in the rubber, so the siloxane is introduced into part of the molecular structure, preventing the penetration of moisture near the molecular chain. However, according to the inventors' investigations, the wiper blade rubber disclosed in Patent Document 2 has a large distance between crosslinks in the molecular chains, large intramolecular spaces, and is therefore not sufficiently suppressed from swelling due to moisture. As a result, as in Patent Document 1, this can cause a decrease in hardness due to swelling, which in turn can increase the contact width with the surface to be wiped, reducing the contact pressure and resulting in a decrease in wiping performance.

[0007] In Patent Documents 1 and 2, the rubber hardness is increased, assuming a decrease in hardness due to swelling. However, a high hardness reduces the contact width with the wiping surface, which can allow foreign matter to get into the gap between the wiper blade and the wiping surface, causing the wiper itself to chip, making it difficult to use for a long time.

[0008] The present disclosure is directed to a blade rubber, wiper blade, and wiper device that suppress changes in hardness due to moisture absorption in response to changes in the humidity environment during use and have high wiping performance throughout durable use. [Means for solving the problem]

[0009] The present disclosure provides a blade rubber that is made of an elastic member containing a polyurethane elastomer and cleans the surface of a member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, In a 24°C environment, the vibration frequency of the blade rubber is 1 x 10 -3 The storage modulus E' at Hz is 12.0 to 18.0 MPa, In pulse NMR measurements of a sample taken from the blade rubber at 50°C, the spin-spin relaxation time (T2 L ) has a segment of 250-360 μs, The polyurethane elastomer has a polysiloxane segment having a structure represented by the following formula (1): the polysiloxane segment is bonded to a structure containing a polyurethane skeleton in the polyurethane elastomer, The blade rubber has a number I of structures represented by formula (1) per polysiloxane segment of 7 to 195. [ka]

[0010] The present disclosure provides a wiper blade, comprising: The wiper blade has a blade rubber and a support member that supports the blade rubber, and the blade rubber is the above-mentioned wiper blade.

[0011] The present disclosure relates to a wiper device, The wiper device includes a wiper arm and a wiper blade attached to the wiper arm, the wiper blade being the wiper blade described above. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a blade rubber, a wiper blade, and a wiper device that suppress changes in hardness due to moisture absorption in response to changes in the humidity environment during use and have high wiping performance throughout durable use. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a wiper device; [Figure 2] FIG. 2 is a schematic diagram of a cross section of a blade rubber. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the present disclosure, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ. Note that when XX is a group, multiple XXs may be selected, and the same applies to YY and ZZ.

[0015] <Wiper blade configuration> A wiper blade according to one embodiment of the present disclosure can be used in vehicles such as automobiles, transportation equipment such as airplanes and ships, and industrial machinery and equipment such as construction machinery. These transportation equipment and industrial machinery and equipment are collectively referred to as vehicles. The present disclosure relates to a blade rubber for a vehicle windshield and a wiper blade equipped with the blade rubber. The windshield is not limited to a front window, but also includes side windows and rear windows.

[0016] Furthermore, the blade rubber and wiper blade according to one aspect of the present disclosure can also be used as a blade rubber and wiper blade for wiping the surface of a protective glass of a lens device or an imaging device such as a network camera. Hereinafter, an embodiment of the wiper blade according to one aspect of the present disclosure will be described in detail, but the present disclosure is not limited thereto.

[0017] <Wiper device> For example, as shown in FIG. 1, a wiper device includes a wiper arm 300 and a wiper blade 110 attached to the wiper arm 300. The wiper arm 300 is connected to, for example, a drive motor (not shown). The wiper blade 110 has a blade rubber 100 and a support member that supports the blade rubber 100. An example of the support member is a tournament 200. The tournament 200 is generally provided with the blade rubber 100 and a vertebra 210 that supports the blade rubber 100.

[0018] 2, the blade rubber 100 comprises a base 1, which is an attachment portion of the blade rubber 100 to the tournament 200, and a lip portion 3 swingably connected to the base portion 1 via a neck portion 2. The wiper blade is formed with a substantially uniform cross-sectional shape in the longitudinal direction.

[0019] In a cross section perpendicular to the longitudinal direction of the blade rubber, the lip portion 3 has a shoulder portion 31 at the end of the lip portion 3 on the neck portion side that extends laterally beyond the neck portion. Furthermore, to stabilize the abutting posture of the blade rubber, it may have a tapered portion 4 whose width gradually decreases from the side closer to the base portion 1 in the direction away from the base portion 1. The degree of gradual decrease in the width of the tapered portion 4 may also change in stages. For example, the lip portion 3 may have a lip tip portion where the degree of gradual decrease in the width of the tapered portion becomes smaller on the side closer to the tip, away from the base portion 1 of the lip. The lip tip portion may have a portion whose width is constant or approximately constant from the side closer to the base portion 1 to the tip.

[0020] The lip tip portion can form the tip of the blade rubber. The blade rubber preferably has a plate shape at least on the tip side of the blade rubber, with a main surface facing the member to be cleaned and a tip surface 7 that forms a tip edge together with the main surface. The blade rubber has, for example, a first main surface 5 and a second main surface 6 opposite to the first main surface 5. The first main surface 5 and the tip surface 7 form a first tip edge 8. The second main surface 6 and the tip surface 7 forms a second tip edge 9.

[0021] The wiper device is not particularly limited, and any known configuration may be adopted, including various types of wiper devices such as a tandem type and an opposed wiping type. The wiper blade is not particularly limited in configuration, and any known configuration may be used. In addition to the tournament type as described above, various types of support members such as a flat type may be used.

[0022] <Analysis of contact state: vibration and contact width> The inventors of the present invention have conducted a detailed analysis of the behavior of the contact portion (tip of the blade rubber) of the blade rubber with the member to be cleaned when the blade rubber is in contact with a stationary member to be cleaned, and the behavior of the tip of the blade rubber when the blade rubber is in contact with the member to be cleaned while moving. As a result, it was found that the ability of the blade rubber to follow the member to be cleaned is 1×10 -3It was found that this is related to the storage modulus of the elastic material at vibration frequencies of 100 Hz.

[0023] The blade rubber remains in contact with the object to be cleaned even when not in operation, so the nip between the object to be cleaned and the blade rubber is formed in a state where the stress is fully relaxed. When the tip of the blade rubber is brought into contact with a transparent flat glass, the blade rubber is operated, and then microscopic observation of the tip of the blade rubber immediately after stopping is performed, it can be seen that the rubber of the blade rubber gradually forms a nip with the glass. The spread of this nip formation is 10 -3 It can be observed that the vibration frequency converges at about 100 Hz. From this, the inventors have determined that this vibration frequency is related to nip formation, i.e., the stability of the contact of the blade rubber with the glass and the ability to follow the glass in the longitudinal direction.

[0024] In a 24°C environment, the vibration frequency of the blade rubber is 1 x 10 -3 The storage modulus of the elastic member at Hz is defined as E'. E' is 12.0 to 18.0 MPa (requirement (1)). By setting E' within this range, the contact width of the blade rubber becomes appropriate, ensuring sufficient contact pressure on the surface to be wiped, ensuring wiping performance and preventing foreign matter from getting caught. The inventors believe that an E' of 18.0 MPa or less indicates that the blade rubber is sufficiently soft when it comes into contact with the member to be cleaned and forms a nip. If E' exceeds 18.0 MPa, the contact width becomes smaller, approaching the size of foreign matter on the surface to be wiped, making it more likely to become trapped in the contact area. This can cause the blade rubber to chip, reducing wiping performance in the chipped area.

[0025] Furthermore, if E' is less than 12.0 MPa, the blade rubber will be too soft when forming the nip, resulting in an excessively large contact width. If the contact width is too large, the contact pressure applied to the contact area will be small, reducing wiping performance and making it difficult to obtain a stable wiping force. Furthermore, tracking performance is also likely to decrease. E' is preferably 12.8 to 18.0 MPa.

[0026] <Method for measuring storage modulus> E' can be obtained by using a dynamic viscoelasticity device to measure under conditions where the frequency and temperature are arbitrarily varied, and creating a master curve at a reference temperature of 24°C from the measurement data. The master curve is created based on the temperature-time conversion rule, with frequency on the horizontal axis and elastic modulus on the vertical axis. The frequency dispersion data measured at each temperature can be created by shifting it along the horizontal axis so that it overlaps with the data at the reference temperature.

[0027] From the obtained master curve, for example, by curve fitting based on the generalized Maxwell model and formulating it, 1 × 10 -3 The storage modulus E' at a vibration frequency of Hz can be calculated. The storage modulus measurement temperature was set at 24°C to simulate the usage environment of blade rubber. This is because it is statistically the environment with the highest usage rate.

[0028] <Moisture absorption control> The elastic material that makes up the blade rubber is prone to a decrease in hardness due to moisture absorption in a high-humidity environment. This decrease in hardness reduces the contact pressure of the blade rubber, causing a decrease in wiping performance. Therefore, in order to prevent a decrease in wiping performance, it is important to prevent a decrease in hardness by suppressing moisture absorption by the elastic material.

[0029] The inventors discovered that moisture absorption can be suppressed by incorporating a densely crosslinked structure in the blade rubber, along with a combination of polyurethane and silicone structures. In other words, the elastic member has a silicone structure within a densely crosslinked polyurethane structure. By giving the blade rubber a dense cross-linked structure, it is possible to reduce the space for moisture to penetrate. Furthermore, by bonding polyurethane with a silicone structure, it is possible to reduce compatibility with moisture, making it even more difficult for moisture to penetrate the polyurethane. In this case, the dense cross-linked structure narrows the space inside the urethane, and the silicone structure bonded to the polyurethane fills this narrow space, synergistically suppressing moisture penetration and effectively suppressing moisture absorption. For example, it is preferable to have a structure in which a dense cross-linked structure and a silicone side chain structure coexist within the polyurethane.

[0030] As mentioned above, in Patent Document 2, siloxane is chemically bonded in the rubber. However, because the distance between crosslinks in the molecular chain is large, moisture swelling is not sufficiently suppressed. In contrast, the blade rubber of the present disclosure has a high crosslink density of polyurethane (requirement (2)) and a structure in which polyurethane and a silicone structure are bonded (requirement (3)), which allows for a more effective moisture absorption suppression effect than a structure in which the siloxane component is simply fixed. As described above, in addition to the storage modulus E' (requirement (1)), the dense cross-linked structure of polyurethane and silicone structures suppresses changes in hardness due to moisture absorption in response to changes in the humidity environment during use, resulting in a blade rubber with high wiping performance throughout durable use. Requirements (2) and (3) will be discussed later.

[0031] <Requirement (2) Crosslink density> Regarding the dense crosslink structure (requirement (2)) mentioned above, the crosslink density of polyurethane is related to the spin-spin relaxation time (T2 L ) The spin-spin relaxation time is correlated with the molecular mobility of polyurethane, and the shorter the spin-spin relaxation time, the lower the molecular mobility. Low molecular mobility means a densely crosslinked structure. Therefore, the crosslink density of polyurethane can be indirectly measured by the spin-spin relaxation time.

[0032] <Spin-spin relaxation time and water swelling> The spin-spin relaxation time T2 is measured by the solid echo method using a pulsed NMR device. The pulsed NMR device is a device for evaluating the mobility of polymer molecules such as rubber from the mobility (relaxation time) of hydrogen atoms in the molecular chain, and in this embodiment, the solid echo method is used as the sequence.

[0033] By measuring the spin-spin relaxation time T2 (transverse relaxation time) of the blade rubber by pulsed NMR measurement, a T2 relaxation curve (free induction decay curve) can be obtained. In this disclosure, the spin-spin relaxation time (T2 L ) has a segment of 250 to 360 μs. That is, the blade rubber is formed of a polyurethane elastomer having a polyurethane segment with a spin-spin relaxation time of 250 to 360 μs.

[0034] Specifically, a T2 relaxation curve is obtained in pulsed NMR measurement. The obtained T2 relaxation curve is separated into two components according to the length of the relaxation time. More specifically, the T2 relaxation curve is separated into two components by curve fitting to the equation described below. Of the two separated components, the T2 L is the T2 relaxation time of the component with the long relaxation time, and T2 S is the T2 relaxation time of the component with a short relaxation time. The component with a long relaxation time is presumed to correspond to the soft segment of the polyurethane elastomer. The component with a short relaxation time is presumed to correspond to the hard segment. L A more specific measurement method will be described later.

[0035] T2 L When T2 is large, the mobility of the polymer molecules is high, which means that the cross-link density within and between the polymer molecules is low. This means that there is a lot of space in the blade rubber to capture water molecules. L Rubber with a large T2 has a high swelling rate due to water. LIf T2 exceeds 360 μs, the rate of reduction in hardness due to swelling becomes large, and it becomes difficult to guarantee the wiping performance of the wiper blade. L is 360 μs or less, preferably 320 μs or less, more preferably 300 μs or less, and even more preferably 290 μs or less.

[0036] T2 L If T2 is small, the mobility of the polymer molecules is small, and the storage modulus tends to be large. As mentioned above, if it becomes too hard, the contact width becomes small, which makes it more likely to get stuck on fine weather, leading to chipping of the blade rubber and a decrease in wiping performance. L is 250 μs or more. T2 L is preferably 260 μs or more, and more preferably 270 μs or more. The spin-spin relaxation time (T2 L ) preferably has a segment of 250 to 320 μs, more preferably has a segment of 260 to 300 μs, and further preferably has a segment of 270 to 290 μs.

[0037] Spin-spin relaxation time (T2 L ) can be controlled within the above range, for example, by increasing the concentration of the crosslinking agent in the raw material composition of the polyurethane. The elastic member contains polyurethane, which may include a polyurethane elastomer composed of a hard segment and a soft segment. In the present disclosure, the term "hard segment" refers to components with low molecular mobility at and near crosslinking points, such as aggregated crystalline components of urethane bonds, nurate bonds, polymeric MDI, trimethylolpropane, etc. The term "soft segment" refers to segments with high molecular mobility between crosslinking points, for example.

[0038] <Requirement (3) Introduction of polysiloxane segments> Regarding the above-mentioned requirement (3), the polyurethane elastomer has a polysiloxane segment having a structure represented by the following formula (1). The polysiloxane segment is bonded to a structure containing a polyurethane skeleton in the polyurethane elastomer.

[0039] [ka]

[0040] The number I of structures represented by formula (1) per polysiloxane segment is 7 to 195. I is preferably 40 to 160.

[0041] Polysiloxane segments are hydrophobic, so they are more effective at repelling water than polyurethane segments. As mentioned above, the spaces between crosslinks in the rubber exist as spaces that can absorb moisture. As shown in Patent Document 1, moisture swelling can also be suppressed by inserting siloxane itself into those spaces. However, because the siloxane is not bonded to the polymer molecules, it is not fixed in the spaces and flows out, making it impossible to maintain the swelling suppression effect for a long period of time.

[0042] The polysiloxane segments are introduced into the polyurethane segments, i.e., the polysiloxane segments are bonded to the polyurethane backbone of the polyurethane elastomer. This bond prevents the polysiloxane segments from flowing out, allowing for a long-term swelling suppression effect. The authors also believe that the alkyl groups on the side chains of the polysiloxane segments can freely rotate around the Si atom, allowing for a swelling suppression effect in adjacent spaces as well.

[0043] For the reasons mentioned above, the alkyl chains on the side chains prevent moisture penetration, but when they are introduced into polyurethane segments as polysiloxane segments, the effect cannot be achieved if the spaces between crosslinks in the rubber are too large. The authors believe that the spaces in Patent Document 2 are too large, making the swelling prevention effect insufficient. Therefore, in this disclosure, the spin-spin relaxation time (T2 L ) (requirement (2))) to which a polysiloxane segment is bonded.

[0044] The polyurethane elastomer preferably contains the structure represented by formula (1) in an amount of 0.5 to 13.0% by mass, more preferably 0.5 to 10.0% by mass, and even more preferably 0.7 to 7.0% by mass. A content of the structure represented by formula (1) of 0.5% by mass or more is preferred because it provides a more sufficient moisture absorption suppression effect. When the content of the structure represented by formula (1) is 13.0% by mass or less, the proportion of the polyurethane elastomer is appropriate, making it easier for the elastomer to uniformly contact the curved surface to be wiped. When the content is 10.0% by mass or less, the followability and wiping performance are improved.

[0045] In the polysiloxane segment, the structures represented by formula (1) may be continuous, or other siloxane structures may be present between them. An example of the bond between the structure represented by formula (1) and the structure containing a polyurethane skeleton is the structure represented by the following formula (1A): In the following structure, R represents a hydrocarbon having 1 to 10 carbon atoms (preferably 1 to 5). The -O- on the left side is bonded to the structure represented by formula (1), and * represents the bond site with the polyurethane skeleton.

[0046] [ka]

[0047] The polysiloxane segment may have an end that is not bonded to the structure containing the polyurethane skeleton. That is, the polysiloxane segment may be a side chain to the polyurethane skeleton. An example of an end that is not bonded to the structure containing the polyurethane skeleton is the structure shown in the following formula (1B). The -O- on the left side is bonded to the structure shown in formula (1). [ka]

[0048] Furthermore, the terminal that is not bonded to the structure containing the polyurethane skeleton may have a structure containing a hydroxyl group and is represented by the following formula (1C): In the following structure, R represents a hydrocarbon having 1 to 10 carbon atoms (preferably 1 to 5). The following structure represents the state when, for example, a silicone oil modified at both ends with carbinol is used for the polysiloxane segment, and one terminal is not bonded to the polyurethane skeleton. [ka]

[0049] The polysiloxane segment may be bonded to the polyurethane skeleton via a structure represented by the following formula (2). [ka] In formula (2), n represents an integer of 1 to 5, and * represents a bonding site with the polyurethane skeleton. The number m of structures represented by formula (2) per polysiloxane segment is preferably 1-10.

[0050] This indicates that the structure of formula (2) exists between the structures of formula (1), and the polysiloxane segment is bonded to the polyurethane skeleton via the structure of formula (2). Furthermore, m = 1 to 10, and when multiple structures of formula (2) exist in the polysiloxane segment, the structures of formula (2) may exist in blocks or randomly. For example, the structure of formula (2) may be bonded to the left and right of the structure of formula (1), but the structures of formula (2) may also exist consecutively. The -O- on the left side of the structure represented by formula (2) can be bonded to Si in the structure represented by formula (1) or the structure represented by formula (2). Si in the structure represented by formula (2) can be bonded to -O- in the structure represented by formula (1) or the structure represented by formula (2). Repeating siloxane units may be bonded to both sides of the structure represented by formula (2).

[0051] The polysiloxane segments are bonded to a structure containing a polyurethane skeleton, such as the structure shown in formula (2). This bond structure allows the polydimethylsiloxane segments to be incorporated into the crosslinked structure of the polyurethane elastomer, more effectively preventing moisture from penetrating into the polyurethane.

[0052] In the above formula (2), m is preferably 2 to 10, and n is more preferably 1 to 3.

[0053] The following polysiloxane is preferably used as the material for the elastic member that constitutes the blade rubber, which makes it possible to obtain a polyurethane elastomer having polysiloxane segments with the structure shown in formula (1) above, in which the polysiloxane segments are bonded to the polyurethane skeleton. As the polysiloxane, various modified silicone oils can be used, among which carbinol-modified silicone oils having a primary hydroxyl group are preferred because they have high reactivity with isocyanates (described below) and can be easily immobilized in polyurethane elastomers.

[0054] The carbinol-modified silicone oil is not particularly limited, and any of a single-terminal modified type, a double-terminal modified type, and a side-chain modified type can be used. In addition, both the terminal and the side chain may be modified. For example, when a carbinol-modified silicone oil modified at both ends is used, the structure represented by formula (1) may have a structure containing a polyurethane skeleton bonded to both ends, or may have a structure containing a polyurethane skeleton bonded to only one end. An example of the bond between the structure represented by formula (1) and the structure containing a polyurethane skeleton is the structure represented by formula (1A) described above. When a side-chain modified carbinol-modified silicone oil is used, the structure represented by formula (1) can be bonded to the polyurethane skeleton via the structure represented by formula (2).

[0055] The polysiloxane segment preferably has a structure in which a polysiloxane having a structure represented by the following formula (3) is urethane-bonded to a structure containing a polyurethane skeleton. [ka] (In formula (3), I and m are the average number of moles added, I is 7 to 195, m is 1 to 10, and n is an integer of 1 to 5. The siloxane structure represented by (-O-Si(CH3)2-) and (-O-Si(CH3)((CH2) n The arrangement of the structure represented by (OH)-) may be a block copolymer or a random copolymer. When the polysiloxane segment has a structure in which polysiloxanes having the structure represented by the above formula (3) are urethane-bonded, the moisture absorption suppression effect is further enhanced. This is presumably because the siloxane is present in the vicinity of the urethane skeleton. In the above formula (3), I is preferably an integer of 40 to 160, m is preferably an integer of 2 to 10, and n is preferably an integer of 1 to 3.

[0056] <Means of achievement> As mentioned above, it is estimated that the components with long relaxation times in pulsed NMR measurements correspond to the soft segments of polyurethane elastomers, and the components with short relaxation times correspond to the hard segments. L Specific means for controlling the mobility of the soft segment and hard segment to set the mobility within the above-mentioned specific range will be described below. 1×10 -3 The elastic modulus in Hz reflects the overall molecular mobility and is affected by both the molecular mobility of the hard segments and the molecular mobility of the soft segments. In the low-frequency region, there is sufficient time for relaxation, so the soft segments, which are components with high molecular mobility, can move freely and contribute little to the elastic modulus. However, the hard segments, which are components with low molecular mobility, cannot move freely, and the magnitude of their molecular mobility contributes to the elastic modulus. In other words, the greater the molecular mobility of the hard segments, the smaller E' becomes, and the smaller the molecular mobility of the hard segments, the larger E' becomes. Therefore, for polyurethanes in blade rubbers according to one embodiment of the present disclosure, it is important to increase the molecular mobility of the hard segments. For example, increasing the molecular mobility of the hard segment makes it easier to control E' low within the above-mentioned specific range.

[0057] Therefore, in order to reduce E', it is preferable to avoid using polymeric MDI as much as possible as a polyurethane raw material, and it is particularly preferable to avoid using it at all. Furthermore, to prevent the formation of crystalline components due to the interaction of soft segment portions, it is preferable to use trimethylolpropane (TMP) as a crosslinking component. By introducing a TMP-derived crosslinking structure into polyurethane, the soft segment portions present between the crosslinking structures are less likely to interact with each other due to the steric hindrance of the TMP-derived crosslinking structure. As a result, the formation of a crystalline structure (crystalline component) due to the interaction of soft segments, i.e., the formation of hard segments, is inhibited.

[0058] In addition, trimethylolpropane has a methylene skeleton adjacent to the hydroxyl group, and therefore a flexible crosslinked structure is formed in terms of molecular structure. As a result, the polyurethane according to one embodiment of the present disclosure has a higher flexibility than polyurethanes having a rigid crosslinked structure derived from polymeric MDI. The molecular mobility of the hard segments increases, making it possible to reduce E'.

[0059] The molecular mobility of hard segments is affected by rigid components. Rigid components are nurates and crystals, and reducing these can increase mobility. Therefore, it is desirable to minimize nurate bonds and make the composition urethane-rich. Specifically, as shown below. In the FT-IR measurement of blade rubber using diamond as the ATR crystal, -1 Peak intensity of 1538 cm -1 The ratio of the peak intensity to the peak intensity (1415cm -1 Peak intensity / 1538cm -1 The peak intensity is preferably 0.50 to 0.65.

[0060] 1415cm -1 The peak at 1538 cm corresponds to the isocyanurate ring. -1 The peak at 1415cm corresponds to the NH bending angle of the urethane bond. -1 Peak intensity / 1538cm -1 When the peak intensity (peak intensity ratio) is greater than 0.65, it indicates the presence of many nurate bonds. Therefore, the rigidity of the nurate reduces the molecular mobility of the hard segments, and E' tends to increase. On the other hand, when the peak intensity ratio is less than 0.50, E' tends to become too small, so a peak intensity ratio of 0.50 to 0.65 is preferred. The peak intensity ratio is more preferably 0.53 to 0.65. In order to make the peak intensity ratio fall within the above range, for example, methods can be used to reduce the nurate bonds and make the polymer urethane-rich by avoiding catalysts that promote nurate formation and using a urethanization catalyst, by bringing the compounding ratio of -NCO to -OH closer to 1, or by setting the reaction temperature to 100°C or less.

[0061] As long as E' is within the above-mentioned specific range, the polyurethane may have a rigid structure such as polymeric MDI as a constituent component. Specific examples are shown below. The blade rubber has a plate shape with a main surface facing the member to be cleaned at least at the tip end of the blade rubber, and a tip end surface 7 that forms a tip end edge (8, 9) together with the main surfaces (5, 6). It is assumed that a line segment is drawn on the tip end surface parallel to the tip end edge, with a distance of 0.5 mm from the tip end edge. The length of the line segment is L', The points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the line segment are designated as P0', P1', and P2', respectively. The samples sampled at P0', P1', and P2' are heated and vaporized in an ionization chamber, and heated to 1000°C at a heating rate of 10°C / s using a direct sample introduction mass spectrometer that ionizes the sample molecules. The resulting detected amount of all ions is designated as M1. The integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value range of 380.5 to 381.5 derived from the polymeric MDI is defined as M2, where M2 / M1 is preferably less than 0.0010.

[0062] It is preferable to use 4,4'-MDI as the isocyanate, which has high reactivity and two isocyanate groups with equal reactivity, while it is preferable to minimize the use of polymeric MDI, which is a trifunctional MDI. Specifically, it is preferable that the M2 / M1 ratio is less than 0.0010. This range makes it easier to satisfy a good E' range. M2 / M1 is more preferably 0.0008 or less. The smaller M2 / M1 is, the more preferable, and although there is no particular lower limit, it is preferably 0.0000 or more. If M2 / M1 is 0.0010 or more, E' tends to become large due to the rigidity of the polymeric MDI.

[0063] Furthermore, to increase the molecular mobility of the hard segments, it is preferable to minimize the amount of crystalline structure. Specifically, it is recommended to minimize the amount of materials that easily form crystalline structures, such as 1,4-butanediol, and to enrich the material with crosslinkers, such as trimethylolpropane. The use of a crosslinking agent such as trimethylolpropane makes it easier to create a distance between urethane bonds, making it difficult for a crystalline structure to form.

[0064] <Molecular mobility of soft segments> The molecular mobility of soft segments is easily affected by the distance between crosslinking points and the structure between crosslinking points. Therefore, for example, the mobility can be reduced by shortening the distance between crosslinking points and increasing the concentration of ester groups in the polyol. One method for shortening the distance between crosslinking points is to increase the concentration of a crosslinking agent such as trimethylolpropane. One method for shortening the distance between crosslinking points is to increase the concentration of the crosslinking agent in the raw material composition of the elastic member. The distance between crosslinking points is desirably about 6000 to 9000 g / mol, depending on the concentration of ester groups. Taking into account the molecular mobility of the hard segments, the concentration of the crosslinking agent in the raw material composition of the elastic member is preferably 0.30 to 0.70 mmol / g, more preferably 0.40 to 0.61 mmol / g, and even more preferably 0.50 to 0.60 mmol / g.

[0065] The method for calculating the crosslinker concentration is described below. For example, it can be quantified by pyrolysis GCMS. Polyhydric alcohols are detected by pyrolysis GC / MS under the following measurement conditions: Device: Pyrolysis equipment: Product name: EGA / PY-3030D, manufactured by Frontier Labs Gas chromatography equipment: TRACE1310 gas chromatograph, Thermo Fisher Scientific Mass spectrometer: ISQLT, manufactured by Thermo Fisher Scientific Pyrolysis temperature: 500℃ GC column: 0.25mm inner diameter x 30m stainless steel capillary column Stationary phase 5% phenylpolydimethylsiloxane Heating conditions: Hold at 50°C for 3 minutes, then heat to 300°C at 8°C / min MS conditions: Mass number range m / z10~650 Scan speed: 1 second / scan The type of polyhydric alcohol is identified by GC / MS. A calibration curve is created by GC analysis of known concentrations of the identified polyhydric alcohol species, and quantification is performed from the GC peak area ratio.

[0066] When the blade rubber is left for 24 hours or more in an environment of 24°C temperature and 50% relative humidity, the hardness is preferably 60.0 to 90.0, and more preferably 70.0 to 80.0. The hardness refers to the International Rubber Hardness Scale (IRHD), and indicates a value measured using a hardness tester according to the International Rubber Hardness Test M Method specified in JIS K 6253.

[0067] The hardness of the blade rubber after being left in an environment of 24°C and 50% relative humidity for 24 hours or more is defined as the initial hardness, and the hardness after being moved to an environment of 24°C and 95% relative humidity and being left there for 24 hours or more is defined as the hardness after being left. The hardness reduction rate calculated by the following formula is preferably 0.00 to 0.90%, and more preferably 0.20 to 0.85%. Hardness reduction rate (%) = (initial hardness at 50% relative humidity - hardness after leaving at 95% relative humidity) / hardness at 50% humidity x 100 The initial hardness and hardness after standing refer to the International Rubber Hardness Scale (IRHD), and indicate values ​​measured using a hardness tester according to the International Rubber Hardness Test M Method specified in JIS K 6253.

[0068] [Blade Rubber] The elastic member constituting the blade rubber contains a polyurethane elastomer, which may be a polyurethane elastomer composed of a hard segment and a soft segment. Polyurethane elastomers are obtained mainly from raw materials such as polyols, chain extenders, crosslinking agents, polyisocyanates, catalysts, and other additives. These raw materials are described in detail below. The polyurethane may include polyester urethane, which includes, for example, polyester polyol as a urethane raw material. Polyurethane elastomers, including the polyester urethane, will now be described.

[0069] Examples of the polyol include polyester polyols such as polyethylene adipate polyol, polybutylene adipate polyol, polyhexylene adipate polyol, (polyethylene / polypropylene) adipate polyol, (polyethylene / polybutylene) adipate polyol, and (polyethylene / polyneopentylene) adipate polyol; polycaprolactone polyols obtained by ring-opening polymerization of caprolactone; polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; and polycarbonate diols. These may be used alone or in combination of two or more. Among the above polyols, polyester polyols using adipate (more preferably butylene adipate) are preferred because they give polyurethane elastomers with excellent mechanical properties.

[0070] As the chain extender, glycols and polyhydric alcohols capable of extending the polyurethane elastomer chain can also be used. Examples of glycols include ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BD), 1,6-hexanediol (1,6-HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol (terephthalyl alcohol), and triethylene glycol. Examples of trihydric or higher polyhydric alcohols include trimethylolpropane, glycerin, pentaerythritol, and sorbitol. These may be used alone or in combination of two or more. These trihydric or higher polyhydric alcohols are preferably used as crosslinking agents. Trimethylolpropane is more preferred.

[0071] Examples of the polyisocyanate include 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polymeric MDI, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), xylene diisocyanate (XDI), 1,5-naphthylene diisocyanate (1,5-NDI), p-phenylene diisocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene diisocyanate (TMXDI), and carbodiimide-modified MDI. Among these, 4,4'-MDI is preferred because it has high reactivity and the two isocyanate groups have equivalent reactivities.

[0072] The catalyst may be a commonly used catalyst for curing polyurethane elastomers, such as a tertiary amine catalyst, and specific examples include the following: amino alcohols such as dimethylethanolamine, N,N,N'-trimethylaminopropylethanolamine, and N,N'-dimethylhexanolamine; trialkylamines such as triethylamine; tetraalkyldiamines such as N,N,N'N'-tetramethyl-1,3-butanediamine; triethylenediamine, piperazine-based compounds, and triazine-based compounds. In addition, organic acid salts of metals such as potassium acetate and potassium alkali octylate can also be used. Furthermore, metal catalysts that are usually used in urethanization, such as dibutyltin dilaurate, can also be used. These can be used alone or in combination of two or more.

[0073] The catalyst is preferably N,N'-dimethylhexanolamine. A commercially available product is Kao Raiser No. 25 (trade name), manufactured by Kao Corporation. This catalyst is suitable for promoting urethanization over nurate formation. Furthermore, since the OH group at the end acts as a catalyst, it also reacts and is incorporated into the interior, reducing the possibility of chemical attack due to seepage. Furthermore, it has good reactivity. An ethylene glycol solution of potassium acetate is also preferred. A commercially available product is POLYCAT 46 (trade name), manufactured by Air Products Japan Co., Ltd.

[0074] For example, the polyurethane elastomer preferably contains, as polyurethane skeleton components, at least one polyol selected from the group consisting of polyester polyols, a trihydric or higher polyhydric alcohol, and 4,4'-MDI. The polyurethane elastomer also contains, as a structural component, a silicone oil having a functional group capable of reacting with an isocyanate group (or a hydroxyl group). The silicone oil can form polysiloxane segments bonded to the polyurethane skeleton.

[0075] For example, the polyurethane elastomer is preferably a reaction product of at least one polyol selected from the group consisting of polyester polyols, a polyisocyanate containing 4,4'-MDI, a trihydric or higher polyhydric alcohol, and a silicone oil having a functional group capable of reacting with an isocyanate group (or a hydroxyl group). Furthermore, the polyurethane elastomer is preferably a reaction product of a urethane prepolymer and a silicone oil having a functional group capable of reacting with an isocyanate group (or a hydroxyl group). The urethane prepolymer is a reaction product of a polyol and a polyisocyanate. The urethane prepolymer is preferably a reaction product of at least one polyol selected from the group consisting of polyester polyols, a polyisocyanate containing 4,4'-MDI, and a trihydric or higher polyhydric alcohol.

[0076] As the polysiloxane that forms the polysiloxane segment, various modified silicone oils having a reactive group among those having a dimethylsiloxane structure can be used. Carbinol-modified silicone oils are preferred. Examples include carbinol-modified silicone oils whose terminals are modified and carbinol-modified silicone oils whose side chains are modified. Among these, carbinol-modified silicone oils having a primary hydroxyl group at the terminal are more preferred, as they have high reactivity with isocyanates and are easily immobilized in polyurethane elastomers. For example, commercially available products include "KF-6001 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)" and "Silmer OH J10 (trade name, manufactured by Siltec Corporation) and X-22-4039 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

[0077] Of the constituent components of the polyurethane elastomer, the content of polyol is preferably 50 to 80 mass %, more preferably 55 to 70 mass %. Among the constituent components of the polyurethane elastomer, the content of polyisocyanate is preferably from 15 to 50 mass %, more preferably from 25 to 40 mass %. Among the constituent components of the polyurethane elastomer, the content of trihydric or higher polyhydric alcohol is preferably 3 to 15 mass %, more preferably 5 to 10 mass %. Among the constituent components of the polyurethane elastomer, the content of silicone oil having a functional group capable of reacting with an isocyanate group (or a hydroxyl group) is preferably 0.1 to 15 mass %, more preferably 0.5 to 10 mass %, and even more preferably 0.7 to 7 mass %.

[0078] The raw materials constituting the blade rubber may contain additives such as pigments, plasticizers, waterproofing agents, antioxidants, ultraviolet absorbers, and light stabilizers, as required.

[0079] <Blade rubber manufacturing method> The method for producing the blade rubber is not particularly limited and can be selected from known methods. For example, the blade rubber can be obtained by injecting a polyurethane elastomer raw material composition into a cavity in a mold for the blade rubber and heating it to harden it.

[0080] The polyurethane elastomer raw material composition contains, for example, at least one polyol selected from the group consisting of polyester polyols, a trihydric or higher polyhydric alcohol, 4,4'-MDI, and a silicone oil having a functional group capable of reacting with an isocyanate group (or a hydroxyl group).

[0081] The method for producing a blade rubber containing a polyurethane elastomer is not particularly limited, but preferably includes the following steps. The method for producing a blade rubber preferably first includes a step of reacting a polyol with a polyisocyanate to obtain a prepolymer. The NCO content in the prepolymer is not particularly limited, but is preferably 3.00 to 15.00 mass%, and more preferably 6.00 to 10.00 mass%.

[0082] Next, the resulting prepolymer is mixed with a mixture (curing agent) of polysiloxane, crosslinking agent, and catalyst that forms the polysiloxane segments to obtain a polyurethane elastomer composition. A polyol may be added to the curing agent. To ensure uniform distances between crosslinking points, it is preferable that the number-average molecular weight of the polyol added to the curing agent be the same as that of the polyol used in the prepolymer. For example, the difference in number-average molecular weight between the two is preferably 500 or less, 200 or less, or 100 or less.

[0083] The polyurethane elastomer composition is then introduced into the mold and cured to obtain a blade rubber. At this time, the mold may be pre-shaped to form a neck portion, a tapered portion, and a lip portion, thereby obtaining a blade rubber having these. A known mold release agent may be applied to the mold.

[0084] The tip of the lip portion of the molded product may be cut off to increase the smoothness of the edge. Alternatively, a blade rubber may be produced by preparing a pair of tandem molded bodies formed so that the lip portions face each other, and then cutting the lip portions in the middle in the longitudinal direction. [Example]

[0085] The present invention will be described below with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples. Raw materials other than those indicated in the Examples and Comparative Examples were reagents or industrial chemicals.

[0086] In the examples and comparative examples, wiper blades were manufactured and evaluated. The formulations and evaluation results for each example are shown in Table 1. Example 1 [Preparation of raw materials for manufacturing wiper blades] (prepolymer) 327.0 g of 4,4'-diphenylmethane diisocyanate (trade name: Millionate MT, manufactured by Tosoh Corporation) (hereafter referred to as MDI) as an isocyanate As a polyol, polybutylene adipate polyester polyol having a number average molecular weight of 2500 (trade name: Nipporan 3027, manufactured by Tosoh Corporation) (hereinafter referred to as PBA2500) was used. )673.0g The above materials were reacted at 80° C. for 3 hours to obtain a prepolymer with an NCO content of 8.80% by weight.

[0087] (hardening agent) 84.3 g of trimethylolpropane (Tokyo Chemical Industry Co., Ltd.) (hereafter referred to as TMP) 0.25 g of N,N'-dimethylhexanolamine (Kao Raiser No. 25, Kao Corporation) (hereafter referred to as No. 25) 8.7g of carbinol-modified silicone oil (product name: KF-6001, manufactured by Shin-Etsu Chemical Co., Ltd.) (hereafter referred to as KF-6001) The above materials were mixed to make a curing agent.

[0088] The resulting prepolymer was mixed with a curing agent to obtain a polyurethane elastomer composition. The polyurethane elastomer composition was then poured into a mold for forming a wiper blade, cured at 130° C. for 5 minutes, and then demolded to obtain a polyurethane molded body.

[0089] Before injecting the polyurethane elastomer composition into the mold, the mold was coated with release agent A. Release agent A was prepared by mixing 5.06 g of ELEMENT14 PDMS 1000-JC (trade name, manufactured by Momentive Performance Materials), 6.19 g of ELEMENT14 PDMS 10K-JC (trade name, manufactured by Momentive Performance Materials), 3.75 g of SR1000 (trade name, manufactured by Momentive Performance Materials), and 85 g of EXXSOL DSP145 / 160. The lip tip of this molded product was appropriately cut to obtain a blade rubber according to this example. The blade rubber had a longitudinal length of 650 mm. The neck thickness was 0.22 mm, and the lip thickness was 0.7 mm. The obtained blade rubber was evaluated by the following methods.

[0090] [Method for measuring dynamic viscoelasticity] The storage modulus E' was measured by temperature frequency dispersion using a dynamic viscoelasticity device, and a master curve was created based on the temperature-time conversion rule and calculated. The conditions are as follows: Apparatus: Dynamic viscoelasticity measuring apparatus (trade name: DMA EXPLEXOR 500N, manufactured by NETZSCH) Measurement mode: tension Static strain: 2% Dynamic strain: 0.5% Measurement temperature: -30℃ to 80℃ (56 points in 2℃ increments) Measurement frequency: 0.1~100Hz (5 points) A master curve was created using the in-device software at a reference temperature of 24°C.

[0091] From the obtained master curve, a mathematical approximation was performed based on the generalized Maxwell model. The generalized Maxwell model is as follows:

number

[0092]

number

[0093] The number of terms in the generalized Maxwell model is the elastic term (E e )1+viscoelastic term (E i )20(i=1~20). τ i is 10 -8 ~10 5 They scored 20 points between them. The difference between E' and E' of the Maxwell model and E' of the master curve is minimized by the GRG nonlinear (generalized reduced gradient method). e , E i Specifically, we used the solver function in Excel. From the obtained master curve approximation formula, the vibration frequency of the blade rubber is 1 × 10 -3 The storage modulus E' at Hz was obtained.

[0094] The measurement samples were prepared as follows. The specimen was prepared so as to include the corner (e.g., the leading edge) of the blade rubber where it contacts the object to be cleaned. It was cut into a strip measuring 50 mm in length, 1 mm in width, and 0.7 mm in thickness (the 50 mm length is part of the blade rubber in the longitudinal direction).

[0095] [T2 L Measurement of T2 relaxation time The spin-spin relaxation time (T2) was measured using the solid echo method in pulsed NMR analysis. The sample was prepared by cutting a piece from the tip of a blade rubber and breaking it into 1 mm x 1 mm pieces, and placing 1 g of the piece in a test tube. The measurement conditions are as follows: Equipment: JNM-MU25 (manufactured by JEOL) Condition: Solid echo method Measurement environment: 50°C Number of measurements: 128 The measurement results were separated into two components by the least squares method using the in-apparatus software, and the spin-spin relaxation time T2 of each was obtained.

[0096] In this example, the T2 relaxation curve is separated into two components according to the length of the relaxation time. Specifically, the T2 relaxation curve is separated into two components by curve fitting to the following equation, and the spin-spin relaxation time (T2 L ), the spin-spin relaxation time of the short-relaxation component (T2 S ) was calculated.

[0097]

number

[0098] M(t): Macroscopic magnetization A L : Intensity of the component with long relaxation time at t=0 T2 L : T2 relaxation time of components with long relaxation times A S : Intensity of the component with short relaxation time at t=0 T2 S : T2 relaxation time of the component with short relaxation time mi: Weibull modulus Measurement position: The length of the tip edge of the blade rubber is L, and samples were taken from the positions of 1 / 8L, 1 / 2L, and 7 / 8L from one end of the edge as described above and measured. The mean surgical value was used.

[0099] [1415cm -1 Peak intensity / 1538cm -1 Measurement method of peak intensity] Measurement was performed using FT-IR. The sample was cut from the tip of the blade rubber. The measurement conditions are as follows: Equipment: FT / IR-4700 (JASCO) Measurement mode: ATR method (crystal: diamond) Accumulation count: 64 times Measurement position: The length of the tip edge of the blade rubber was taken as L, and samples were taken as described above from positions 1 / 8L, 1 / 2L, and 7 / 8L from one end of the edge and measured, and the arithmetic average value was used.

[0100] [Method for measuring M2 / M1] The M2 / M1 ratio was measured by the direct sample introduction method (DI method), in which the sample was directly introduced into the ion source without passing through a gas chromatograph (GC). The apparatus used was POLARIS Q manufactured by Thermo Fisher Scientific Inc., and a Direct Exposure Probe (DEP) was used. Assuming that a line segment was drawn parallel to the leading edge of the blade rubber at a distance of 0.5 mm from the leading edge, the length of the line segment was L', and polyurethane was scraped off with a biocutter from points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the line segment (referred to as P0', P1', and P2', respectively). That is, three samples were taken from one leading edge of the blade rubber.

[0101] 0.1 μg of sample to be sampled at each of P0′, P1′, and P2′ was fixed to a filament at the tip of the probe and directly inserted into the ionization chamber, which was then rapidly heated from room temperature to 1000°C at a constant temperature increase rate (10°C / s), and the vaporized gas was detected by a mass spectrometer. The amount of detected ions, M1, was determined as the sum of the integrated intensities of all peaks in the obtained total ion current thermogram. Furthermore, the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value range of 380.5 to 381.5 derived from the polymeric MDI was defined as M2, and M2 / M1 was calculated. The arithmetic mean of the values ​​obtained for P0', P1', and P2' was defined as the value of M2 / M1 in the present disclosure.

[0102] <Measurement of siloxane components> Siloxane components can be analyzed using the following method. For example, a method using trimethyl orthoformate as a methoxy derivatizing agent is known. Trimethyl orthoformate, methanol, sulfuric acid, and an elastic material are mixed and reacted at reflux temperature for several hours to decompose the siloxane segments into siloxane units. This can then be analyzed by GCMS to analyze and quantify the structure.

[0103] More specifically, the analysis can be carried out as follows. The structure represented by formula (1) can be quantified by the following method. A standard sample was prepared by mixing 524 mg of silicone oil (product name "KF-96A-100cs", manufactured by Shin-Etsu Chemical Co., Ltd.), 272 mg of sulfuric acid, 28.4 g of trimethyl orthoformate, and 8.75 g of methanol, and reacting the mixture at reflux temperature for 5 hours. The solution after the reaction was diluted with a solvent to create four levels of different concentrations. The four samples were analyzed by GCMS, and a calibration curve was created using the peak intensity and concentration of the Si-O component.

[0104] Next, a measurement sample is cut out from the center of the blade rubber. The measurement sample was 524 mg, sulfuric acid 272 mg, trimethyl orthoformate 28.4 g, methano The mixture is mixed with 8.75 g of alcohol and reacted at reflux temperature for 5 hours. After the reaction, the supernatant is sampled and analyzed by GCMS. The mass percentage of the structure represented by formula (1) in the polyurethane elastomer is calculated from the peak intensity of the Si-O component and the calibration curve.

[0105] Regarding the structure shown in formula (2), the sample after the above reaction is 1 The structure can be estimated by H-NMR analysis. When it has the structure shown in formula (2), that is, when a side-chain modified silicone oil is used, the structure is one in which two methoxy groups and one methyl group are bonded to the Si at the end of the polyurethane elastomer. On the other hand, when a terminally modified silicone oil is used, the bond between the polysiloxane segment and the polyurethane backbone can be detected as a structure in which one methoxy group and two methyl groups are bonded to the Si at the end of the polyurethane elastomer. The structure can be inferred from the peak intensity ratio of the two bonds.

[0106] <Evaluation of moisture absorption rate> A piece is cut from the center of the blade rubber into a strip 50 mm long, 1 mm wide, and 0.7 mm thick, and left in an environment at 24°C and 50% relative humidity for at least 24 hours before measuring the initial mass.The sample is then moved to an environment at 24°C and 95% relative humidity and left there for at least 24 hours, after which the mass is measured and the moisture absorption rate is calculated using the following formula. Moisture absorption rate (%) = (mass after standing at 95% relative humidity - initial mass at 50% relative humidity) / initial mass at 50% relative humidity × 100 The 50 mm length is part of the longitudinal direction of the blade rubber.

[0107] <Evaluation of hardness reduction rate> A piece of the blade rubber was cut from the center into a strip measuring 50 mm in length, 1 mm in width, and 0.7 mm in thickness, and left in an environment with a temperature of 24°C and a relative humidity of 50% for at least 24 hours before measuring its initial hardness. The 50 mm length was a portion of the blade rubber in the longitudinal direction. The hardness measurement was performed as follows: Equipment: Wallace hardness tester (manufactured by Wallace) Conditions: International rubber hardness test M method specified in JIS K 6253 Hardness: International Rubber Hardness (IRHD) Next, the sample is transferred to an environment with a temperature of 24°C and a relative humidity of 95% and left for 24 hours or more, and then the hardness after leaving is measured, and the hardness reduction rate is calculated using the following formula. Hardness reduction rate (%) = (initial hardness at 50% relative humidity - hardness after storage at 95% relative humidity) / initial hardness at 50% relative humidity × 100

[0108] <Follow-up evaluation> The uniformity of contact of the blade rubber was evaluated using a testing device for wiping performance testing as specified in Japanese Industrial Standards (JIS) D5710:1998 (Automotive parts - Wiper arms and wiper blades). Water droplets were sprayed onto the entire glass surface, which was the member to be cleaned, using a spray bottle, and the wiper was operated to and fro under the following conditions. After this, the glass surface was visually inspected and evaluated. The evaluation was carried out by attaching the device to the driver's seat side of a Toyota Wish (model number: ZNE10G). [Wiping conditions] Wiping environment: Temperature 20±5℃, relative humidity 70% or more Wiper blade length: 650mm Wiper blade load: 18N / m Wiper blade reciprocating speed: 55 times / min Water application: Water droplets are sprayed onto the entire glass surface in a mist <Evaluation criteria> Rank A: Almost the entire surface can be wiped. Rank B: Five or fewer very fine streaks less than 0.5 mm wide remain. Rank C: Two or fewer fine streaks less than 1.0 mm wide remain. Rank D: Fine streaks remain over the entire surface (6 or more very fine streaks less than 0.5 mm wide, 3 or more fine streaks less than 1.0 mm wide, or 1 or more streaks 1.0 mm wide or wider).

[0109] <Evaluation of wiping performance in rainy weather> The wiping performance of the blade rubber was evaluated using a testing device for the wiping performance test described in Japanese Industrial Standards (JIS) D5710:1998 (Automotive parts - Wiper arms and wiper blades). Water droplets were sprayed onto the entire glass surface, which was the member to be cleaned, using a spray bottle, and the wiper was operated back and forth once under the conditions described below. After this, the glass surface was visually inspected and evaluated. The evaluation was carried out after the device was attached to the driver's side of a Toyota Wish (model number: ZNE10G). [Blade rubber pre-treatment] Assuming use in rainy weather, the product was left in an environment of 25°C and 80% relative humidity for more than 24 hours, and performance evaluation was carried out. [Wipe-off conditions] Wiping environment: Temperature 20±5℃, relative humidity 70% or more Wiper blade length: 650mm Wiper blade load: 18N / m Wiper blade reciprocating speed: 55 times / min Water application: Water droplets are sprayed onto the entire glass surface in a mist <Evaluation criteria> Rank A: Almost the entire surface can be wiped. Rank B: Five or fewer very fine streaks less than 0.5 mm wide remain. Rank C: Two or fewer fine streaks less than 1.0 mm wide remain. Rank D: Fine streaks remain over the entire surface (6 or more very fine streaks less than 0.5 mm wide, 3 or more fine streaks less than 1.0 mm wide, or 1 or more streaks 1.0 mm wide or wider).

[0110] <Durability evaluation assuming use of washer fluid on sunny days> Using the testing equipment for wiping performance tests specified in Japanese Industrial Standards (JIS) D5710:1998 (Automotive parts - Wiper arms and wiper blades), the blade rubber was moved back and forth under the following conditions. The test below simulates the use of washer fluid on sunny days. After the blade rubber was moved back and forth 100,000 times, the wiping performance was evaluated under the above-mentioned rainy weather conditions to evaluate durability. [Blade rubber pre-treatment] The blade rubber was left in an environment of 25°C and 50% relative humidity for more than 24 hours. [Test conditions] Wiping environment: Temperature 20±5℃ Wiper blade length: 650mm Wiper blade load: 15N / m Wiper blade reciprocating speed: 45 times / minute or more Spray water evenly over the entire surface of the glass. 800mL / min or more The water used for spraying was a mixture of JIS test powder 1, type 11 (manufactured by the Japan Powder Industry and Engineering Association) at 3 mass %.

[0111] <Examples 2 to 15 and Comparative Examples 1 to 5> A prepolymer and a curing agent were prepared in the same manner as in Example 1, except that the ingredients and amounts were changed as shown in Tables 1 and 2, to obtain a polyurethane elastomer composition. A blade rubber was produced using the obtained polyurethane elastomer composition. The results were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2. Details of the materials used other than those shown in Example 1 are shown below.

[0112] Polybutylene adipate polyester polyol having a number average molecular weight of 2000 (trade name: Nipporan 4010, manufactured by Tosoh Corporation) (hereinafter referred to as PBA2000) Polyhexylene adipate polyester polyol having a number average molecular weight of 1,000 (trade name: Nipporan 164, manufactured by Tosoh Corporation) (hereinafter referred to as PHA1000) Polymeric MDI (trade name: Millionate MR-400, manufactured by Tosoh Corporation) (hereinafter referred to as pMDI) 1,4-Butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as 1,4-BD) POLYCAT46 (manufactured by Air Products Japan) (hereinafter referred to as PC46) Silmer OH J10 (manufactured by Siltec Corporation) X-22-4039 (Shin-Etsu Chemical Co., Ltd.) KF-96A-100cs (Shin-Etsu Chemical Co., Ltd.)

[0113] [Table 1]

[0114] [Table 2]

[0115] In Tables 1 and 2, formula (2)m indicates the number m of structures represented by formula (2) per polysiloxane segment. Note that a value of m of 0 indicates that the polyurethane elastomer does not have a structure represented by formula (2). Furthermore, % in formula (1) indicates the content (mass %) of the structure represented by formula (1) in the polyurethane elastomer. IRHD indicates the hardness (initial hardness) after the blade rubber is left in an environment of 24°C and 50% relative humidity for 24 hours or more.

[0116] The present disclosure relates to the following configurations. (Configuration 1) A blade rubber made of an elastic member containing a polyurethane elastomer, which cleans the surface of a member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, In a 24°C environment, the vibration frequency of the blade rubber is 1 x 10 -3 The storage modulus E' at Hz is 12.0 to 18.0 MPa, In pulse NMR measurements of a sample taken from the blade rubber at 50°C, the spin-spin relaxation time (T2 L ) has a segment of 250-360 μs, The polyurethane elastomer has a polysiloxane segment having a structure represented by the following formula (1): the polysiloxane segment is bonded to a structure containing a polyurethane skeleton in the polyurethane elastomer, the number I of structures represented by formula (1) per polysiloxane segment is 7 to 195; A blade rubber characterized by: TIFF2025177805000014.tif40153 (Configuration 2) The polysiloxane segment is bonded to the polyurethane skeleton via a structure represented by the following formula (2): 2. The blade rubber according to claim 1, wherein the number m of structures represented by the following formula (2) per one polysiloxane segment is 1 to 10: TIFF2025177805000015.tif45153 (In formula (2), n represents an integer of 1 to 5, and * represents a bonding site with the polyurethane skeleton.) (Configuration 3) 3. The blade rubber according to claim 2, wherein m is 2 to 10. (Configuration 4) In the pulsed NMR measurement, the spin-spin relaxation time (T L 4. The blade rubber according to any one of configurations 1 to 3, wherein a segment of 250 to 320 μs is present. (Configuration 5) 5. The blade rubber according to any one of configurations 1 to 4, wherein the polyurethane elastomer contains 0.5 to 10.0 mass % of the structure represented by formula (1). (Configuration 6) 6. The blade rubber according to any one of configurations 1 to 5, wherein the polysiloxane segment has a structure in which a polysiloxane having a structure represented by the following formula (3) is urethane-bonded to the polyurethane skeleton. TIFF2025177805000016.tif43153 In formula (3), I and m are the average number of moles added, I is 7 to 195, m is 1 to 10, and n is an integer of 1 to 5. In formula (3), The siloxane structure and (-O-Si(CH3)((CH2) n The arrangement of the structure represented by (OH)-) may be a block copolymer or a random copolymer. (Configuration 7) In the FT-IR measurement of the blade rubber using diamond as the ATR crystal, 1415cm -1 Peak intensity of 1538 cm -1 7. The blade rubber according to any one of configurations 1 to 6, wherein the ratio of the peak intensity to the peak intensity is 0.50 to 0.65. (Configuration 8) the blade rubber has a plate shape at least at a tip end side of the blade rubber, the plate shape having a main surface facing the member to be cleaned and a tip end surface forming a tip end edge together with the main surface, Assuming that a line segment is drawn on the tip surface parallel to the tip edge at a distance of 0.5 mm from the tip edge, The length of the line segment is L', The points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the line segment are designated as P0', P1', and P2', respectively. The sample sampled at each of P0', P1', and P2' is heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction mass spectrometer. The sample is heated to 1000°C at a heating rate of 10°C / s. The detected amount of all ions is M1. When the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value in the range of 380.5 to 381.5 derived from polymeric MDI is defined as M2, M2 / M1 is less than 0.0010 The blade rubber according to any one of configurations 1 to 7. (Configuration 9) A wiper blade, The wiper blade has a blade rubber and a support member that supports the blade rubber, A wiper blade, characterized in that the blade rubber is the blade rubber according to any one of configurations 1 to 8. (Configuration 10) A wiper device, The wiper device includes a wiper arm and a wiper blade attached to the wiper arm, A wiper device, wherein the wiper blade is the wiper blade described in configuration 9. [Explanation of symbols]

[0117] 1: blade support portion, 2: neck, 3: lip portion, 4: tapered portion, 5: first tapered surface, 6: second tapered surface, 7: tip surface, 8: first edge, 9: second edge 100: Wiper blade, 200: Tournament, 210: Vertebra, 300: Wiper arm

Claims

1. A blade rubber made of an elastic member containing a polyurethane elastomer, which cleans the surface of a member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, In a 24°C environment, the vibration frequency of the blade rubber is 1 x 10 －３ The storage modulus E' at Hz is 12.0 to 18.0 MPa, In pulse NMR measurement of a sample sampled from the blade rubber in a 50°C environment, the spin-spin relaxation time (T2 Ｌ ) has a segment of 250-360 μs, The polyurethane elastomer has a polysiloxane segment having a structure represented by the following formula (1): the polysiloxane segment is bonded to a structure containing a polyurethane skeleton in the polyurethane elastomer, the number I of the structure represented by formula (1) per polysiloxane segment is 7 to 195; A blade rubber characterized by:

2. The polysiloxane segment is bonded to the polyurethane skeleton via a structure represented by the following formula (2):

2. The blade rubber according to claim 1, wherein the number m of structures represented by the following formula (2) per one polysiloxane segment is 1 to 10: (In formula (2), n represents an integer of 1 to 5, and * represents a bonding site with the polyurethane skeleton.)

3. The blade rubber according to claim 2, wherein m is 2 to 10.

4. In the pulsed NMR measurement, the spin-spin relaxation time (T Ｌ 2. The blade rubber according to claim 1, wherein there is a segment in which the average length of the tensile strength is 250 to 320 μs.

5. 2. The blade rubber according to claim 1, wherein the polyurethane elastomer contains 0.5 to 10.0 mass % of the structure represented by formula (1).

6. The polysiloxane segment is a polysiloxane having a structure represented by the following formula (3):

2. The blade rubber according to claim 1, wherein the polyurethane has a structure in which the amine is urethane-bonded to the polyurethane skeleton. (In formula (3), I and m are the average number of moles added, I is 7 to 195, m is 1 to 10, and n is an integer of 1 to 5. In formula (3), (—O—Si(CH ３ ) ２ -) and a siloxane structure represented by (—O—Si(CH ３ ) ((CH ２ ) ｎ The arrangement of the structure represented by (OH)-) may be a block copolymer or a random copolymer.

7. In the FT-IR measurement of the blade rubber using diamond as an ATR crystal, 1415 cm －１ The peak intensity of 1538 cm －１ 2. The blade rubber according to claim 1, wherein the ratio of the peak intensity to the peak intensity is 0.50 to 0.

65.

8. the blade rubber has a plate shape at least at a tip end side of the blade rubber, the plate shape having a main surface facing the member to be cleaned and a tip end surface forming a tip end edge together with the main surface, Assuming that a line segment is drawn on the tip surface parallel to the tip edge at a distance of 0.5 mm from the tip edge, The length of the line segment is L', The points 1 / 8L', 1 / 2L', and 7 / 8L' from one end of the line segment are designated as P0', P1', and P2', respectively. The sample sampled at each of P0', P1', and P2' is heated and vaporized in an ionization chamber, and the sample molecules are ionized using a direct sample introduction type mass spectrometer. The sample is heated to 1000°C at a heating rate of 10°C / s. The detected amount of all ions is M1, When the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value in the range of 380.5 to 381.5 derived from the polymeric MDI is defined as M2, M2 / M1 is less than 0.0010 The blade rubber according to claim 1.

9. A wiper blade, The wiper blade has a blade rubber and a support member that supports the blade rubber, A wiper blade, characterized in that the blade rubber is the blade rubber according to any one of claims 1 to 8.

10. A wiper device, The wiper device includes a wiper arm and a wiper blade attached to the wiper arm, A wiper device, wherein the wiper blade is the wiper blade according to claim 9.

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