JP6498265B1 - Seat cushion and seat - Google Patents

Abstract

Provided is a cushioning material for a seat having excellent ride comfort.
A reaction-cured product formed by using an isocyanate component of a diphenylmethane diisocyanate-based compound, and having a foamed urethane containing a hard segment and a soft segment. The foamed urethane is hard in H ¹ solid-state pulse NMR measurement. The first region in which the segment spin-spin relaxation time (T2) is 30 μsec or more and 40 μsec or less and the hard segment volume existence ratio is 10% or more and 40% or less, and is disposed on the seating surface side. In the region 1 and the H ¹ solid-state pulse NMR measurement, the hard segment spin-spin relaxation time (T2) is 20 μsec or more and less than 30 μsec, and the volume existence ratio of the hard segment is 5% or more and 40% or less. A region adjacent to the first region and And a second region disposed on the side away from the seating surface.
[Selection] Figure 1

Description

  The present disclosure relates to a seat cushion material and a seat.

  For example, urethane foam is used as a cushioning material. Moreover, the cushion material which has the site | part from which hardness differs together is known for the cushion material (for example, refer patent documents 1-3).

For example, Patent Document 1 discloses a laminated cushion body. This laminated cushion body is manufactured by inserting one or more partition plates into the mold, injecting different foaming raw materials into the mold with the partition plate as a boundary, and then pulling out the partition plates in accordance with the foaming speed. .
Patent Document 2 discloses a foam cushion body having different hardness. In this foam foam body with different hardness, urethane foams having different hardnesses are connected at least directly through the apertures of a heat-meltable synthetic resin film in which many slits are opened by heating during foaming.
Patent Document 3 discloses a different hardness cushion body in which portions having different hardnesses are formed. This different hardness cushion body forms a cushion body by bonding fibers of a fiber aggregate on cotton in which fibers are three-dimensionally entangled with a urethane binder, and a fiber aggregate is formed on a part of the cushion body. Is packed and combined with the binder.

Japanese Patent No. 60-2119018 Japanese Patent Laid-Open No. 06-106627 Japanese Examined Patent Publication No. 04-034496

  An object of the present disclosure is to provide a seat cushion material excellent in ride comfort, a vehicle seat cushion material, a vehicle seat cushion material, and a seat.

  Means for solving the above problems include the following aspects.

<1> A reaction-cured product formed using an isocyanate component of a diphenylmethane diisocyanate compound, having a urethane foam containing a hard segment and a soft segment,
The urethane foam has a hard segment spin-spin relaxation time (T2) of 30 μsec or more and 40 μsec or less and a hard segment volume existence ratio of 10% or more and 40% or less in H ¹ solid-state pulse NMR measurement. Area,
In the H ¹ solid-state pulse NMR measurement, a second region in which the spin-spin relaxation time (T2) of the hard segment is 20 μsec or more and less than 30 μsec, and the volume ratio of the hard segment is 5% or more and 40% or less, A second region adjacent to the first region;
A cushioning material for seats.
<2> The seat cushion material according to <1>, wherein the Asker F hardness in the first region is 20 or more and less than 50, and the Asker F hardness in the second region is 50 or more and 70 or less.
<3> When the Asker F hardness in the first region is F1, and the Asker F hardness in the second region is F2, the absolute value of the difference between F1 and F2 is 10 or more and 50 or less <2 > Cushioning material for seat.
<4> In any one of <1> to <3>, the isocyanate component includes an isocyanate terminal-modified polyisocyanate reacted with a mixture of monomeric diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate and a part of the polyol component. Seat cushion material as described.
<5> The seat cushion material according to any one of <1> to <4>, wherein the seat cushion material is for a vehicle.
<6> The seat cushion material according to any one of <1> to <5>, wherein the seat cushion material is for a vehicle.
<7> A seat that supports the buttocks of the seated occupant,
A backrest that supports the back and waist of the seated occupant;
With
At least one of the seat portion and the backrest portion is a seat having the seat cushion material according to <1> to <6>.

  According to the cushion material of the present disclosure, a seat cushion material excellent in ride comfort, a vehicle seat cushion material, a vehicle seat cushion material, and a seat are provided.

It is sectional drawing which shows an example of the cushion material for seats of this indication. It is a perspective view showing an example of a seat of this indication. It is an exploded view showing an example of a seat of this indication. (A) is a perspective view which shows an example of a pressurizing plate, (B) is AA sectional drawing in (A). It is a graph which shows typically an example of a compression-deflection curve. It is a graph showing the relationship between the thickness from the surface of foamed urethane in Example 2 and Example 4 and the spin-spin relaxation time (T2), and the relationship between the thickness from the surface of foamed urethane and Asker F hardness.

  Hereinafter, an embodiment which is an example of the seat cushion material of the present disclosure will be described.

<Cushion material for seat>
The cushion material for seats of this indication is a reaction hardened material formed using the isocyanate ingredient of diphenylmethane diisocyanate type compound, and has foamed urethane containing a hard segment and a soft segment.
The urethane foam has a hard segment spin-spin relaxation time (T2) of 30 μsec or more and 40 μsec or less and a volume ratio of the hard segment of 10% or more and 40% or less in H ¹ solid-state pulse NMR measurement. It has the area of.
In the H ¹ solid-state pulse NMR measurement, the spin-spin relaxation time (T2) of the hard segment is 20 μsec or more and less than 30 μsec, and the volume existence ratio of the hard segment is 5% or more and 40% or less; It has 2nd area | region adjacent.
The seat cushion material of the present disclosure is used by being disposed on the occupant side on which the first region is seated and on the side away from the occupant side on which the second region is seated.

Here, an example of the seat cushion material of the present disclosure will be described with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating an example of the seat cushion material of the present disclosure. The seat cushion material 100 is formed of urethane foam. The foamed urethane is a reaction cured product formed by using an isocyanate component of a diphenylmethane diisocyanate compound, and includes a hard segment and a soft segment. In addition, the seat cushion material 100 includes a first region 102 and a second region 104 adjacent to the first region 102. In the seat cushion material 100, the boundary between the first region 102 and the second region 104 is not clearly formed. The first region is a region disposed on the seating surface side. The second region is a region disposed on the side away from the seating surface.
In this specification, the seating surface represents a surface on the side that supports the buttocks and a surface on the side that supports the back and the waist when the occupant sits on the seat.

The first region 102 and second region 104, the ^{H 1} solid pulsed NMR spectrometer, shows the following characteristics.
The first region has a hard segment spin-spin relaxation time (T2) of 30 μsec or more and 40 μsec or less and a hard segment volume existence ratio of 10% or more and 40% or less in H ¹ solid-state pulse NMR measurement.
In the second region, the spin-spin relaxation time (T2) of the hard segment is 20 μsec or more and less than 30 μsec, and the volume existence ratio of the hard segment is 5% or more and 40% or less.

  In the seat cushion material 100, the boundary between the first region 102 and the second region 104 is ambiguous, but is not limited to this. The boundary between the first region 102 and the second region 104 may be ambiguous or may be clearly formed. Further, the cross-sectional shape of the seat cushion material 100 is not limited to the shape shown in FIG. In the following description, reference numerals are omitted.

Conventionally, urethane foam is also applied to a cushion material for a seat for a vehicle such as a vehicle. Urethane foam used as a cushion material for seats for vehicles is required to improve riding comfort while maintaining a flexible cushioning property at an appropriate foaming ratio (about 60 kg / m ³ ). In order to meet this requirement, urethane foam is increasing the abundance ratio of hard segments in the urethane foam.
The hard segment has a high melting point or a high glass transition temperature. For this reason, the hard segment contributes to high modulus and high strength. The hard segment is a part that expresses the strength of the urethane foam in particular.

  On the other hand, the soft segment has a glass transition temperature lower than room temperature (eg, 25 ° C.). For this reason, the soft segment contributes to high elongation and elastic recovery. The soft segment is a part that expresses the flexibility of the urethane foam.

Here, the conventional urethane foam is considered to have a high proportion of hard segments (for example, a form of a large aggregate structure in which urea bonds are dense) in the foamed resin (parts forming a skeleton and a film) of the urethane foam. It is done.
When the conventional urethane foam was subjected to H ¹ pulse NMR measurement in vacuum at 25 ± 1 ° C., the hard segment obtained by H ¹ pulse NMR (nuclear magnetic resonance) measurement in vacuum at 25 ± 1 ° C. The spin-spin relaxation time (T2) is less than 30 μsec throughout. Therefore, it is considered that the conventional urethane foam forms a large aggregate structure in which urea bonds are densely formed (for example, an aggregate structure of urea bonds having a diameter of 10 nm or more). In addition, as the volume ratio of the hard segment is increased, it is considered that the structure has a higher ratio of the urea bond aggregate structure. In other words, when the spin-spin relaxation time (T2) of the hard segment is less than 30 μsec and the volume existence ratio of the hard segment is large, a structure having a large number of large aggregate structures with dense urea bonds is formed. It is guessed.
Note that the measurement temperature of 25 ± 1 ° C. represents that an error is allowed up to a range of ± 1 ° C. with reference to 25 ° C. Hereinafter, the meaning of “±” represents the same meaning (that is, an error up to the numerical value described on the right side is allowed based on the numerical value described on the left side of ±).

  Moreover, in the cushion material for seats using the conventional foaming urethane, the hardness as the whole cushion material for seats is high. This is thought to be due to the presence of many large aggregate structures with dense urea bonds. Therefore, when the seat cushion material using urethane foam is applied as a seat cushion material for a vehicle, the load when the occupant is seated is difficult to disperse. As a result, this cushion material for seats has a low soft feel and low body pressure dispersibility (fit feeling), and also tends to cause a bottom sensation and a foreign body sensation. In addition, the seat cushion material is less likely to disperse vibration and has low vibration absorption. Therefore, the seat cushion material using the conventional urethane foam is inferior in riding comfort.

  Here, for example, the cushion materials disclosed in Patent Literature 1 to Patent Literature 3 are made of different hardness cushion materials having different hardness parts using different raw materials, thereby improving riding comfort. However, the different hardness cushion materials disclosed in Patent Documents 1 to 3 do not sufficiently satisfy the required riding comfort characteristics when applied as seat cushion materials for vehicles, and there is room for further improvement. It was. In addition, the different hardness cushion materials disclosed in Patent Documents 1 to 3 are manufactured using different raw materials, which is disadvantageous in terms of equipment and labor.

On the other hand, the cushion material for seats of this indication has specific foaming urethane. The urethane foam has a first region and a second region adjacent to the first region. Each region has the aforementioned characteristics in H ¹ solid-state pulse NMR measurement at 25 ± 1 ° C. in vacuum.

  Since the seat cushion material of the present disclosure has the above characteristics, the viscosity is considered to be dominant as a whole as compared with the conventional seat cushion material. Further, in the first region, since it has the above characteristics, it is difficult to form an aggregate structure in which urea bonds are dense, and it is considered that urea bonds exist alone. Therefore, it is considered that the viscosity is dominant in the first region. In addition, since the second region has the above characteristics, an aggregate structure in which urea bonds are denser is more easily formed than in the first region. On the other hand, urea-bound aggregates are considered to exist in a small state. Therefore, it is considered that the second region is more elastic than the first region.

The first area in the urethane foam is an area arranged on the seating surface side (side close to the occupant) when the occupant is seated. Moreover, the 2nd area | region in urethane foam becomes an area | region arrange | positioned on the opposite side (side away from a passenger | crew) to the seating surface side.
Therefore, in the first region, by having the above characteristics, the urethane foam is expanded by the load when the occupant is seated, and the pressure is dispersed. Further, in the second region, the above-described characteristics serve to maintain the posture of the seated occupant. Therefore, the seat cushion material of the present disclosure is excellent in a flexible feel, body pressure dispersibility, and vibration absorbability, and has a bottom sensation and a foreign object feeling suppressed. As a result, it is considered that an occupant seated on the seat cushion material of the present disclosure comes to feel that the ride comfort is excellent.
From the above, it is estimated that the seat cushion material of the present disclosure is excellent in ride comfort.

Here, when the central portion of the urethane foam including the first region and the second region is cut in the thickness direction, the ratio of the thickness of the first region and the second region of the urethane foam among the cut surfaces Is, for example, in the following range.
Ratio (h1 / h0) of the first region thickness (h1) to the total thickness (h0) of the urethane foam: 5% or more and 35% or less The thickness (h2) of the second region with respect to the total thickness (h0) of the urethane foam Ratio (h2 / h0): 65% or more and 95% or less

In the present disclosure, the first region and the second region are separated for convenience as follows.
A measurement sample is taken in the thickness direction from the central portion of the urethane foam including the first region and the second region. The collected specimen is measured for spin-spin relaxation time (T2) according to the following H ¹ solid-state pulse NMR measurement. Of the measurement samples collected in the thickness direction, a region where the spin-spin relaxation time (T2) is 30 μsec or longer is defined as a first region. A region where the spin-spin relaxation time (T2) is less than 30 μsec is set as a second region.

  Here, with reference to FIG. 6, the relationship between the spin-spin relaxation time (T2) of the hard segment at each position in the thickness direction of the urethane foam will be described. FIG. 6 is represented as a biaxial graph. FIG. 6 shows the relationship between the thickness from the surface of urethane foam and the spin-spin relaxation time (T2) in Example 2 and Example 4 described later, and the relationship between the thickness from the surface of urethane foam and Asker F hardness. It is a graph to represent. The first vertical axis (left vertical axis) shown in FIG. 6 is the spin-spin relaxation time (T2) of the hard segment, and the horizontal axis is the depth in the thickness direction of urethane foam ("thickness from the surface layer"). Is written). The second vertical axis (right vertical axis) is Asker F hardness (denoted as “F hardness”).

  In addition, as shown in FIG. 6, the total thickness of the urethane foam in Example 2 and Example 4 to be described later is 100 mm. The spin-spin relaxation time (T2) and Asker F hardness are measured by the methods described later. However, the graph shown in FIG. 6 shows the measured values of all the test pieces collected by slice cutting every 5 mm in the thickness direction.

From the graph shown in FIG. 6, the respective ranges of the region where the spin-spin relaxation time (T2) of the hard segment is 30 μsec or more and the region where the hard segment is less than 30 μsec are known. That is, the range of the first region and the second region is known. As shown in FIG. 6, it can be seen that the first region is in the range of about 10 mm or less for the foamed urethane of Example 2 and the range of about 25 mm or less for the foamed urethane of Example 4. Similarly, it can be seen that the second region is in the range of greater than about 10 mm for the foamed urethane of Example 2 and is greater than about 25 mm for the foamed urethane of Example 4.
Therefore, the thickness (h1) of the first region is in the range of 5% to 35% with respect to the total thickness (h0), and the thickness (h2) of the second region is with respect to the total thickness (h0). It can be seen that the range is 65% or more and 95% or less.
From FIG. 6, in both Example 2 and Example 4, in the first region, the spin-spin relaxation time (T2) of the hard segment gradually changes from the surface toward the thickness direction of the urethane foam. . On the other hand, in the second region, it can be seen that there is little change in the spin-spin relaxation time (T2) in the thickness direction of the urethane foam.
In the present disclosure, the spin-spin relaxation time of the hard segment is not limited to that shown in FIG.

(H ¹ solid-state pulse NMR measurement)
Here, the spin-spin relaxation time (T2) and volume abundance ratio in the H ¹ solid-state pulse NMR (Nuclear Magnetic Resonance) measurement will be described.

First, the H ¹ solid pulse NMR measurement will be described. In the present specification, the H ¹ solid-state pulse NMR measurement was performed in a vacuum at 25 ± 1 ° C. using a seat cushion material to be measured, which was vacuum-dried at room temperature all day and night, and a vacuum sealed tube as a test piece. Is. Specific measurement conditions are shown below.

-Measurement conditions-
Measuring device: JNM-MU25 (resonance frequency 25 MHz) manufactured by JEOL
Measuring method: Solid echo method Measuring temperature: 25 ± 1 ° C
Pulse width: 90 ° pulse, 2.3 μs
Repeat time: 4 sec
Integration count: 32 times (foamed sample)
The analysis results (spin-spin relaxation time (T2) and volume existence ratio of the hard segment) are based on the assumption that the value of Variance dispersion is 25 or less. Variance variance indicates the degree of data dispersion, and is represented by the average of the squares of deviations.

In addition, the test piece for measuring the first region is sampled by cutting every 5 mm from a portion including the outer surface (for example, the mold bottom side surface) corresponding to the first region of the seat cushion material. . And the surface of the outer surface side of the cushion material for seats is measured among the collected test pieces.
Further, the test piece for measuring the second region is a 15 mm portion (for example, from the mold upper side to the mold bottom side) from the outer surface corresponding to the second region of the seat cushion material toward the first region. Cut out the slices every 5 mm toward the specimen, and take a specimen containing a 15 mm site). And the position of 15 mm is measured toward the 1st area | region from the outer surface corresponded to the 2nd area | region of the cushion material for seats in the extract | collected test piece.

In the H ¹ solid-state pulse NMR measurement, the amount of the component of the measurement object can be evaluated using the difference in relaxation time.
When H ¹ solid-state pulse NMR measurement is performed on the measurement object, an FID signal (free induction decay) is obtained as a response to the pulse. The initial value of the FID signal is proportional to the number of protons in the measurement sample. For example, when the measurement object has a plurality of components such as a hard segment and a soft segment, the FID signal is the sum of the response signals of the respective components. If there is a difference in mobility depending on the components, the spin-spin relaxation time (T2) is different. Therefore, by separating the spin-spin relaxation time (T2), the relaxation time of each component and the ratio (volume existence ratio) of each component can be obtained. As the component mobility decreases, the spin-spin relaxation time (T2) decreases. As the mobility increases, the spin-spin relaxation time (T2) increases. That is, the hard component has a shorter spin-spin relaxation time (T2), and the softer component has a longer spin-spin relaxation time (T2).

When foamed urethane having a hard segment and a soft segment is measured, in the H ¹ solid-state pulse NMR measurement, there is a difference in mobility between the hard segment and the soft segment, so the spin-spin relaxation time (T2) of the two is different. . The hard segment has a short spin-spin relaxation time (T2), and the soft segment has a long spin-spin relaxation time (T2). That is, the spin-spin relaxation time (T2) becomes shorter as the urea bond aggregate structure is formed, and the spin-spin relaxation time (T2) becomes longer as the urea bond aggregate structure is suppressed. Become.
In addition, the spin-spin relaxation time (T2) is shorter as the volume ratio of the hard segment is larger (that is, the urea bond aggregate structure is formed).

From the above, in the H ¹ solid-state pulse NMR measurement in vacuum at 25 ± 1 ° C., the spin-spin relaxation time (T2) of the hard segment in the first region and the second region is in the above range. This is considered to mean that there are few hydrogen bonds between urea bonds in the aggregate structure of urea bonds in the urethane foam (that is, there are few large aggregate structures with dense urea bonds).

  In particular, the fact that the spin-spin relaxation time (T2) is 30 μsec or more and 40 μsec or less in the first region is considered that urea bonds in a state close to monodispersion exist. Further, in the second region, the fact that the spin-spin relaxation time (T2) is 20 μsec or more and less than 30 μsec is considered that a small urea bond aggregate exists.

  The fact that the volume existence ratio of the hard segment in the first region is 10% or more and 40% or less and the volume existence ratio of the hard segment in the second region is in the range of 5% or more and 40% or less indicates that the aggregate of urea bonds It is considered that the structure is suppressed to a structure in which the existence ratio of hydrogen bonds between urea bonds in the structure is small (that is, the number of aggregate structures with dense urea bonds is small).

(Various physical properties)
The foamed urethane contained in the seat cushion material of the present disclosure preferably has the following physical properties in that the seat cushion material has excellent riding comfort.

-Asker F hardness-
In the urethane foam, when the Asker F hardness in the first region is F1, and the Asker F hardness in the second region is F2, the absolute value of the difference between F1 and F2 (| F1-F2 |) is 10 or more and 50 or less. It is good that it is. The absolute value of the difference between F1 and F2 may be 10 or more and 45 or less, or 10 or more and 40 or less.
Further, the Asker F hardness in the first region and the second region is not particularly limited. For example, the following range is preferable.
The Asker F hardness in the first region is preferably 20 or more and less than 50. The lower limit of Asker F hardness in the first region may be 25 or more. Further, the upper limit of Asker F hardness in the first region may be 45 or less, or 40 or less.
The Asker F hardness in the second region is preferably 50 or more and 70 or less. The upper limit of Asker F hardness in the second region may be 65 or less, or 60 or less.
When the absolute value of the difference in Asker F hardness in each region and the Asker F hardness in each region are in the above ranges, the ride comfort is excellent. The Asker F hardness in the first region and the second region is considered to be caused by, for example, the size of the urea bond aggregate and the amount of the urea bond aggregate.

The Asker hardness measurement method uses an ASKER hardness meter F type, and measures the surface hardness of the seat cushion material to be measured under a temperature condition of 21 ± 2 ° C.
The Asker F hardness is a value after 20 seconds have elapsed after installing an Asker hardness tester F type on the surface of the first and second regions of the seat cushion material to be measured on the surface at the following positions. Read and measure.
1st area | region: The outer surface equivalent to the 1st area | region of the cushioning material for seats is measured.
Second region: A position of 15 mm (for example, a surface obtained by slicing every 5 mm) is measured from the outer surface corresponding to the second region of the seat cushion material toward the first region.

  Reference is now made again to FIG. From FIG. 6, it can be seen that the foamed polyurethanes of Examples 2 and 4 have a smaller Asker hardness as the spin-spin relaxation time (T2) of the hard segment increases. It can be seen that the Asker F hardness in the first region is lower than the Asker F hardness in the second region. That is, it can be seen that the Asker F hardness correlates with the spin-spin relaxation time (T2) of the hard segment. Furthermore, both of the foamed polyurethanes of Example 2 and Example 4 have Asker F hardness (F1: F hardness at a position of 0 mm from the surface layer shown in FIG. 6) in the first region and Asker in the second region. It can be seen that the absolute value of the difference from the F hardness (F2: F hardness at a position near the thickness of 85 mm from the surface layer shown in FIG. 6) is in the range of 10 to 50. In the present disclosure, the Asker F hardness is not limited to that shown in FIG.

-Hysteresis loss-
Hysteresis loss of foamed urethane is an indicator of body pressure dispersibility, bottom-up feeling, and foreign object feeling of the seat cushion material. The range of the hysteresis loss is not particularly limited, and is preferably 8% or more and 20% or less, for example.

The hysteresis loss is a value obtained by a compression deflection test. The hysteresis loss is calculated from a compression-deflection measurement curve by a constant load compression method in accordance with JIS K6400-2 (2012).
Specifically, a test piece of 380 mm long × 380 mm wide (thickness is the product thickness) is cut out from the seat cushion material to be measured and used as a measurement sample. Next, at room temperature (21 ± 2 ° C .; room temperature in the following measurement is 21 ± 2 ° C.), press plate (steel plate: see FIG. 4 (A) and FIG. 4 (B)) in the vertical direction. The thickness when a load is applied at 10 mm / min and a pressure is applied at 4.9 N is taken as the initial thickness. After determining the initial thickness, it is compressed and bent at a compression rate of 150 mm / min until the maximum load is 980 N. Next, the pressure plate is returned to the initial thickness at the same speed and allowed to stand for 1 minute for preliminary compression. After 1 minute, the pressure plate is again compressed and bent to a maximum load of 980 N at a compression speed of 150 mm / min. Thereafter, the pressure plate is returned to the initial thickness at the same speed, and the measurement history is shown in a graph (see FIG. 5).

FIG. 5 is a graph schematically showing an example of a compression-deflection curve. The hysteresis loss is surrounded by the origin 0-curve A-point B-curve C-point D with respect to the area 0ABE0 of the area surrounded by the origin 0-curve A-point B-point E-origin 0 in the graph shown in FIG. The area of each region is expressed as a percentage (percent (%)) of 0ABCD, and is obtained by the following formula.
(Formula) Hysteresis loss Af = ((Area 0ABCD / Area 0ABE0) × 100)
In FIG. 5, the horizontal axis DR (%) represents the deflection rate (%), and the vertical axis L (N) represents the load.

-Elastic repulsion-
The elastic rebound rate of urethane foam is an index of the fit of the seat cushion. The elastic repulsion is not particularly limited, and may be, for example, 35% or more and 50% or less.
The elastic repulsion rate is measured according to JIS K6400-3 (2011). Specifically, a test piece of 50 mm × 100 mm × 100 mm or more is cut out from the target seat cushion material, and a steel ball having a diameter of 16 mm and a mass of 16 g is dropped from a height of 500 mm from the upper surface of the test piece at room temperature. The maximum height bounced is expressed as a percentage (percent (%)) of the fall height (500 mm).

-Logarithmic decay rate-
The logarithmic attenuation factor of urethane foam is an index of vibration absorption of the seat cushion material. The logarithmic attenuation factor is originally a parameter for evaluating the attenuation of the material, and the larger this value, the higher the damping performance.
The logarithmic decay rate is measured in accordance with JIS K6394 (2007). Specifically, the logarithmic attenuation rate is obtained by dividing the logarithmic attenuation rate (Λ) by 2π in the damped vibration waveform on the response side obtained by the excitation test at room temperature. The logarithmic decay rate (Λ) is determined by taking the natural logarithm of the ratio (An / An + 1) of the adjacent amplitude heights An.
In general, the value of the attenuation factor has a value that is different for each natural vibration mode called the first natural mode, the second natural mode, or the like in order from the lowest frequency.
Therefore, the logarithmic decay rate is measured for the subject seat cushion material as follows. In the seat cushion material of the present disclosure, the attenuation rate average value is calculated from the average value of the attenuation rates of a plurality of eigenmodes appearing in the frequency range of 0 Hz to 500 Hz, and is used as a representative value indicating the vibration damping performance. The method for determining the attenuation rate is as follows. First, a transfer function (a ratio of an excitation force as an input to a response as an output) is obtained from the excitation test result. Then, the calculated function value is processed by a curve fitting method to calculate an attenuation rate for each mode. Through this calculation process, the natural frequency for each mode can also be calculated.

In addition, about the said hysteresis loss, an elastic repulsion rate, and a logarithmic attenuation factor, the measurement position of the cushion material for seats used as a measuring object is as follows.
The measurement of the first region includes the first region of the test piece (400 mm × 400 mm × 100 mm thickness), and the center of the thickness of the test piece (the first thickness from the outer surface of the first region toward the second region). The measurement sample is cut out so that the thickness of the outer surface of the region is 50 mm). Then, by applying a load (performing each test) on the outer surface of the first region, the hysteresis loss, the elastic restitution rate, and the logarithmic decay rate are measured.
The measurement of the second region is performed by measuring 25 mm toward the outer surface of the first region in the thickness direction with respect to the thickness center of the test piece (50 mm from the outer surface of the first region). A sample for measurement is cut out so that the total thickness is 50 mm at 25 mm toward the surface. This measurement sample is cut out so as to be in a range corresponding to the second region. Then, by applying a load to the cut surface on the first region side of the measurement sample (performing each test), the hysteresis loss, the elastic rebound rate, and the logarithmic decay rate are measured.

(Heat heat compression set)
Next, the wet heat compression set will be described. The wet heat compression set is a measurement of compression set after 50% compression for 22 hours under conditions of a temperature of 50 ° C. ± 2 ° C. and a relative humidity of 95%.
Specifically, the seat cushion material to be measured is cut into a thickness of 40 mm ± 1 mm and used as a test piece. The thickness (t0) of this test piece is measured, compressed and fixed to 50% of the thickness of the test piece, and left in a high-humidity thermostatic chamber at 50 ° C. ± 2 ° C. and a relative humidity of 95% for 22 hours. Thereafter, the fixed test piece is taken out, and the thickness (t1) of the test piece after 30 minutes is measured. Then, let the value calculated | required by the following formula be the value of wet heat compression set.
(Formula) Wet heat compression set (%) = {(t0−t1) / t0} × 100

  Humid heat compression set (compression set after 50% compression for 22 hours under conditions of temperature 50 ° C. ± 2 ° C. and relative humidity 95%) is, for example, a realistic use environment of a vehicle seat. Reflecting, it is known as a reliability test over time under the condition of applying compressive load and wet heat. By measuring the final thickness change (permanent strain) of the cushioning material for seats, the wet heat compression set can be expected to change in vibration absorption, rebound resilience, bottom sensation, and the like. That is, the wet heat compression set is an index that can be used to know the effect of the seat cushion material on the ride comfort over time when applied to a vehicle seat.

  As an index representing the ride comfort of the seat cushion material over time, it is desirable that the wet heat compression set is small.

The urethane foam included in the seat cushion material of the present disclosure may have a compression set of 1% or less after 50% compression for 22 hours under conditions of a temperature of 50 ° C. ± 2 ° C. and a relative humidity of 95%. Good. Preferably it is 0.8% or less, More preferably, it is 0.5% or less.
That the wet heat compression set is 1% or less means that the compression set over time under wet heat conditions is kept low. Therefore, when the seat cushion material of this indication is applied to the cushion material for seats for vehicles, for example, it has shown that the more stable and excellent ride comfort can be obtained with time.
In addition, since the lower the wet heat compression set, the better the riding comfort over time, the lower limit value of the wet heat compression set is preferably 0%, but the lower limit value is not particularly limited.

  Hereinafter, urethane foam which is a material of the seat cushion material of the present disclosure will be described. The urethane foam is a urethane foam having open cells.

The cushion material for seats of this indication has foaming urethane formed using the isocyanate ingredient of diphenylmethane diisocyanate type compound. Specifically, the urethane foam is a reaction cured product obtained by reaction curing of a mixed raw material of an isocyanate component of a diphenylmethane diisocyanate compound, a polyol component, a catalyst, and a foaming agent.
In particular, urethane foam uses a polyisocyanate component obtained by reacting a mixture of monomeric diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate with a part of the polyol in advance in order to improve the riding comfort of the seat cushion material. It is preferable that the reaction cured product is formed.

  Hereinafter, each component for forming foaming urethane is demonstrated.

(Isocyanate component)
First, the isocyanate component of the diphenylmethane diisocyanate compound will be described. Hereinafter, diphenylmethane diisocyanate may be referred to as “MDI”.
The MDI compound is not particularly limited. For example, pure (pure) diphenylmethane diisocyanate (monomeric MDI), polymeric MDI, a mixture comprising monomeric MDI and polymeric MDI, an isocyanate-terminated polyisocyanate of polymeric MDI, and an isocyanate terminal comprising monomeric MDI and polymeric MDI Examples include modified polyisocyanates.

  Specifically, for example, 2,2′-diphenylmethane diisocyanate (2,2′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 4,4′-diphenylmethane diisocyanate (4,4 '-MDI), and monomeric MDI of these mixtures; polymeric MDI of polymethylene polyphenylene polyisocyanate; mixture of monomeric MDI and polymeric MDI; isocyanate-terminated modified poly-reacted monomeric MDI with a portion of the polyol component Isocyanate; isocyanate-terminated polyisocyanate obtained by reacting polymeric MDI with a part of polyol component; isocyanate-terminated polyisocyanate obtained by reacting a mixture of monomeric MDI and polymeric MDI with part of polyol component A mixture of an isocyanate-terminated polyisocyanate obtained by reacting a monomeric MDI with a part of a polyol component and an isocyanate-terminated polyisocyanate obtained by reacting a polymeric MDI with a part of a polyol component; and a monomeric MDI and a polymeric MDI And a mixture containing at least one of a monomeric MDI and a polymeric MDI in an isocyanate-terminated polyisocyanate obtained by reacting a mixture of the above with a part of a polyol component. These diphenylmethane diisocyanate compounds may be used alone or in combination of two or more.

  Among these, the MDI compound is an isocyanate-terminated polyisocyanate obtained by reacting a mixture of a monomeric MDI and a polymeric MDI with a part of the polyol component in order to improve the riding comfort of the seat cushion material. (That is, a prepolymer obtained by reacting a mixture of monomeric MDI and polymeric MDI with a part of the polyol component). More preferably, it is an isocyanate-terminated polyisocyanate obtained by reacting a mixture of monomeric MDI and polymeric MDI with a part of the polyol component. When this isocyanate terminal-modified polyisocyanate is used, formation of a urea bond aggregate structure is easily suppressed.

  In an isocyanate-terminated polyisocyanate obtained by reacting a mixture of a monomeric MDI and a polymeric MDI with a part of a polyol component, the mixing ratio (mass ratio) of the monomeric MDI and the polymeric MDI is the molar ratio of the polymeric MDI to the polymeric MDI. The mass ratio (monomeric MDI / polymeric MDI) is preferably in the range of 30/70 to 90/10. More preferably, it is the range of 32/68 or more and 80/20 or less. When the MDI mixing ratio (mass ratio) of the monomeric MDI and the polymeric MDI is in the range of 30/70 or more and 90/10 or less, it is possible to suppress the foam from deviating from the characteristics as the cushion material for the seat. Furthermore, a decrease in moldability is suppressed.

  The isocyanate-terminated polyisocyanate obtained by reacting a mixture of monomeric MDI and polymeric MDI with a part of the polyol component should be adjusted so that the NCO content (mass%) is finally 10 or more and 30 or less. Is preferred.

(Polyol component)
The polyol component is not particularly limited. Since the seat cushion material of the present disclosure may be applied to a vehicle seat (particularly a vehicle seat), it is difficult to cause hydrolysis (excellent hydrolysis resistance) as an polyol component. Polyols are preferred. Specific examples of ether polyols include PPG (polyoxypropylene polyol, polyoxyethylene polyol, polyoxyethylene polyoxypropylene polyol), PTMG (polytetramethylene ether glycol), and PEG (polyethylene glycol). Those having —O— bonds (ether bonds) such as

  The average molecular weight of the polyol component is preferably in the range of 200 to 10,000 (preferably 600 to 9000) in terms of weight average molecular weight. The weight average molecular weight per number of functional groups of the active hydrogen group (OH group) may be in the range of 200 to 4000 (preferably 300 to 3000).

(catalyst)
The catalyst is not particularly limited, and various urethanization catalysts known in the field of urethane foam used as a seat cushion material can be used. For example, triethylamine, triethyldiamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N, N ′, N ′, N ″ -pentamethyldiethylenetriamine, bis- (2-dimethylaminoethyl) ether, triethylenediamine, 1,8-diaza-bicyclo (5,4,0) undecene-7,1,2- Amine-based catalysts of amine compounds such as dimethylimidazole, dimethylethanolamine, N, N-dimethyl-N-hexanolamine; organic acid salts of these amine compounds; stannous octoate; organometallic compounds such as zinc naphthenate . Further, amine-based catalysts having active hydrogen such as N, N-dimethylethanolamine and N, N-diethylethanolamine are also included. These catalysts may be used alone or in combination of two or more.

  The addition amount of the catalyst is preferably 0.01% by mass or more and 10% by mass or less with respect to the polyol component. When it is 0.01% by mass or more, curing shortage is easily suppressed, and when it is 10% by mass or less, a decrease in moldability is suppressed.

(Foaming agent)
The foaming agent is preferably a foaming agent containing water, and is preferably water alone.
What is necessary is just to set as the quantity of the water used as a foaming agent by the target foaming ratio with respect to 100 mass parts of polyol components.
When the foaming agent is used in combination with water, examples of the foaming agent other than water include methylene chloride, hydrochlorofluorocarbons (HCFC-123, etc.), hydrofluorocarbons (HFC-245fa, etc.), butane, pentane (cyclopentane). , Isopentane, normal pentane) and the like; organic acids such as formic acid; and the like.
Further, as a foaming agent, in addition to a foaming agent containing water, air, nitrogen gas, liquefied carbon dioxide or the like may be mixed and dissolved in a mixed raw material for obtaining foamed urethane. What is necessary is just to set the quantity of foaming agents other than water by the target foaming ratio.

(Other ingredients)
The other components are components (additives) added as necessary. Examples of other components include a crosslinking agent, a colorant, a filler, a flame retardant, an antioxidant, an ultraviolet absorber, an antistatic agent, and a foam stabilizer. When other components are used, these may be used alone or in combination of two or more as required.

(Molar ratio of isocyanate group to active hydrogen group in mixed raw material)
In the mixed raw material for obtaining foamed urethane, the isocyanate index (NCO INDEX) represented by the molar ratio of isocyanate group to active hydrogen group (NCO group / active hydrogen group) is not particularly limited. The isocyanate index is preferably 90 or more and 120 or less, for example, in order to obtain excellent riding comfort. The lower limit of the isocyanate index may be 95 or more, or 100 or more. The upper limit of the isocyanate index may be 115 or less, or 110 or less. Here, the isocyanate index is a percentage of a value obtained by dividing the number of moles of isocyanate groups in the isocyanate component by the total number of moles of active hydrogen groups capable of reacting with the isocyanate groups (hydroxyl of the polyol component, water as a blowing agent, etc.). Desired.
In addition, in this specification, an isocyanate index represents the value in the case of carrying out reaction hardening of the mixed raw material for obtaining foaming urethane containing the component which can react with an isocyanate component and an isocyanate component. Therefore, it does not represent the isocyanate index for obtaining the isocyanate component of the isocyanate-terminated polyisocyanate.

  Below, the manufacturing method of the urethane foam used for the cushion material for seats of this indication is demonstrated.

(Method for producing urethane foam)
It does not specifically limit as a manufacturing method of foaming urethane, The well-known method in the molding method formed in a slabstock method and a type | mold is applicable.
As an example of a preferable method for producing foamed urethane, for example, a first step of preparing an isocyanate component of a diphenylmethane diisocyanate compound, and a second step of molding a raw material obtained by mixing the isocyanate component, the polyol component and the foaming agent are used. The method which has a process is mentioned.

  As the first step, for example, a polyisocyanate component prepared by mixing a mixture of monomeric MDI and polymeric MDI with a part of a polyol in advance (that is, a mixture of monomeric MDI and polymeric MDI is one of the polyol components). It is preferable to prepare an isocyanate-terminated polyisocyanate) reacted with a part. The mixture of the monomeric MDI and the polymeric MDI is preferably 30/70 or more and 90/10 or less (mass ratio) as the mixing ratio of the monomeric MDI / polymeric MDI. Moreover, it is preferable to adjust so that an isocyanate group (NCO group) may finally become 10-30 by NCO content (mass%). The isocyanate component-modified polyisocyanate obtained by reacting a mixture of monomeric MDI and polymeric MDI with a part of the polyol component is not limited, and an isocyanate component similar to the aforementioned isocyanate component may be used.

As a 2nd process, it is the process of shape | molding the mixed raw material containing the isocyanate component prepared by the 1st process, a polyol component, and a foaming agent.
Hereinafter, as an isocyanate component of the diphenylmethane diisocyanate compound in the first step, a case where an isocyanate terminal-modified polyisocyanate prepared by reacting a mixture of monomeric MDI and polymeric MDI with a part of the polyol component will be described. Moreover, the case where it shape | molds by the mold method shape | molded in a type | mold as a 2nd process is demonstrated.

In the second step, the above-mentioned mixed raw material is poured into a mold, and foamed at a predetermined temperature in the mold, thereby obtaining a reaction cured product of urethane foam.
Generally, from the injection of the raw material into the mold until just before the reaction starts, the relatively large molecular weight is easier to move toward the mold bottom, the smaller the molecular weight, the more active the molecular motion, There is a tendency that the reaction easily proceeds while moving to the upper surface side of the separated mold.
When a mixed raw material using the above-mentioned isocyanate terminal-modified polyisocyanate is injected into the mold, a region having a high content of isocyanate-terminated polyisocyanate mainly containing polymeric MDI is formed in the region on the mold bottom side. Conceivable. On the other hand, in the area | region of the type | mold upper surface side, it is thought that the area | region where the existence ratio of the isocyanate terminal modified polyisocyanate mainly containing monomeric MDI is high is formed.

Isocyanate-end-modified polyisocyanate mainly containing polymeric MDI has poor molecular movement and short movement distance, and therefore has poor reactivity. As a result, it is considered that small urea bond aggregates are not easily formed in the region on the mold bottom side, and urea bonds are likely to exist alone.
On the other hand, an isocyanate terminal-modified polyisocyanate mainly containing monomeric MDI has high molecular reactivity and high reactivity because of its long movement distance. As a result, it is considered that small urea-bonded aggregates are more easily formed in the region on the mold upper surface side than in the region on the mold bottom side.

The temperature of the mold when foaming is preferably in the range of 30 ° C. or higher and 50 ° C. or lower (preferably lower limit is 35 ° C. or higher, and preferable upper limit is 45 ° C. or lower). When the temperature of the mold is within this range, the molecular motion is slow and the reactivity with water is poor in the region on the bottom side of the mold. Therefore, the production rate of urea bonds is slow. Moreover, even if a urea bond is generated, a urea bond aggregate is hardly formed. The urea bond tends to be monodispersed.
On the other hand, in the upper region of the mold, it reacts with an exothermic reaction with water. Therefore, compared with the area | region of the type | mold bottom side, reactivity becomes active and a small urea bond aggregate is easy to be formed.

As a result, in the obtained urethane foam reaction cured product, the hard segment spin-spin relaxation time (T2) was 30 μsec or more and 40 μsec in the region on the mold bottom side in H ¹ solid-state pulse NMR measurement at 25 ± 1 ° C. In the following, it becomes easy to control the volume existence ratio of the hard segment within a range of 10% to 40%. Further, in the region on the upper surface side of the mold, the hard segment spin-spin relaxation time (T2) in the H ¹ solid-state pulse NMR measurement at 25 ± 1 ° C. is 20 μsec or more and less than 30 μsec, and the hard segment volume existence ratio is 5 It becomes easy to control in the range of not less than 40% and not more than 40%. That is, the region on the mold bottom side is the first region, and the region on the mold upper surface side adjacent to the first region is the second region.
Thus, according to the preferable manufacturing method, a urethane foam having regions exhibiting different characteristics can be obtained from a single raw material, and thus a cushion material for a seat excellent in riding comfort can be obtained. Furthermore, cost improvements are expected.

  When the temperature of the mold during foam molding exceeds 50 ° C. (for example, 60 ° C. or higher), the skin contains a urea-bonded aggregate structure on the surface of the urethane foam in contact with the mold in the mold. A layer is easily formed. As a result, the ride comfort is likely to decrease. In addition, if it is less than 30 degreeC, manufacture of foaming urethane will become difficult.

  In the second step, the order of preparing the mixed raw material is that the polyol component is previously mixed with the catalyst and the blowing agent (premix), and then mixed with the isocyanate component prepared in the first step. Also good. Moreover, you may mix the isocyanate component prepared by the 1st process, a catalyst, a foaming agent, and a polyol component, respectively.

  Further, in the method for producing foamed urethane, in all the steps of the first step and the second step, if moisture is present in the production environment of the foamed urethane, the isocyanate component of the diphenylmethane diisocyanate compound reacts with the moisture. Urea bonds are likely to occur. Therefore, it is preferable to manufacture in a nitrogen purge atmosphere in all steps of the manufacturing process of urethane foam. In a nitrogen purge atmosphere, the formation of urea bond aggregate structures is likely to be suppressed.

  In this specification, the term “process” is not limited to an independent process, and may be used as long as the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. include.

(Use)
Since the cushion material for seats of this indication is excellent in riding comfort, it is suitable as a cushion material for vehicles (boats, airplanes, vehicles, virtual reality devices, etc.). Among these, it is more preferable to be applied to a vehicle seat cushion material. As an example of the seat for vehicles, the seat of each vehicle is mentioned, For example, the seat of a car and a railroad is mentioned. In addition, there are seats for vehicles such as cultivators, tractors, power shovels, hydraulic cranes, excavators, bicycles and the like. In particular, it is suitable to be applied to an automobile seat. In addition, the present invention may be applied to a cushion material for a seat used in facilities such as a theater and a movie theater.

<Seat>
Next, an embodiment as an example of a seat to which the seat cushion material of the present disclosure is applied will be described.

  The seat of this indication is provided with the seat part which supports the seated crew member's buttocks, and the backrest part which supports the seated crew member's back and waist. And at least one of a seat part and a backrest part has the cushion material for seats of this indication. In the seat cushion material of the present disclosure, the first region of urethane foam is disposed on the seating surface (that is, the seated occupant side).

  Here, the seat cushion material of the present disclosure may be applied to both the seat portion and the backrest portion, or may be applied to either the seat portion or the backrest portion. The seat cushion material of the present disclosure is preferably applied to at least the seat portion. And the cushion material for seats of this indication may be applied to some seat parts.

Hereinafter, an example of the seat of the present disclosure will be described with reference to the drawings.
FIG. 2 is a perspective view illustrating an example of the seat of the present disclosure. The seat 200 shown in FIG. 2 is shown as an example of a car seat. As shown in FIG. 2, the seat 200 is a seat used in the front row of the vehicle. The seat 200 includes a seat portion 202 that supports the buttocks of the seated occupant and a backrest portion 204 that supports the back and waist of the seated occupant. The surface of the seat portion 202 has the cushion skin 18, and the surface of the backrest portion 204 has the back skin 20. The seat 200 (hereinafter referred to as “seat 200”) includes a headrest 22 that supports the head of the passenger.

  FIG. 3 is an exploded view illustrating an example of the seat of the present disclosure. FIG. 3 shows an exploded view of the sheet 200 shown in FIG. As shown in FIG. 3, the seat 200 includes a frame 12 as a support, a seat cushion 14 attached to the frame 12, a seat back 16 attached to the frame 12, and a headrest 22 attached to the frame 12. I have. Further, the seat 200 includes a cushion skin 18 as an example of the skin covering the seat cushion 14 and a back skin 20 as an example of the skin covering the seat back 16.

  The frame 12 includes a cushion frame 30 that supports the seat cushion 14, a back frame 32 that supports the seat back 16, and a pair of head brackets 34 that support the headrest 22.

  Further, the rear end side of the cushion frame 30 in the front-rear direction of the seat and the lower end side of the back frame 32 in the vertical direction are connected via a shaft member 36 extending in the seat width direction. The back frame 32 swings around the shaft member 36 as the center of rotation.

  The head bracket 34 is attached to the upper end side of the back frame 32, and two head brackets 34 are provided at intervals in the seat width direction. The head bracket 34 has a cylindrical shape extending in the vertical direction, and a pair of support bars 22 </ b> A provided in the headrest 22 are inserted therein. Thereby, the headrest 22 is supported by the frame 12 (head bracket 34).

  The seat cushion 14 is formed of a seat cushion material formed of urethane foam. The seat cushion 14 according to the present disclosure is applied to the seat cushion 14. The 1st field in foamed urethane which the cushion material for seats of this indication has is arranged so that it may become the seated crew member side. The seat cushion 14 includes a pair of side support portions 40 that suppress a seated occupant from sliding in the seat width direction. The side support portions 40 are formed at both ends of the seat cushion 14 in the seat width direction, extend in the front-rear direction of the seat, and protrude upward as compared with other portions.

  The seat cushion 14 has a main portion 42 disposed between the pair of side support portions 40, a main front portion 44 disposed in front of the main portion 42 in the seat front-rear direction, and the main portion 42. And a main rear portion 46 disposed behind the seat in the front-rear direction. The main part 42 supports the seated occupant's buttocks, and the main front part 44 supports the seated occupant's thigh.

  A groove portion 48 extending in the front-rear direction of the seat is formed between the main front portion 44, the main portion 42, the main rear portion 46, and the pair of side support portions 40, and the cushion skin 18 is fixed inside the groove portion 48. Wires (not shown) used in the above are disposed.

  Further, a groove 50 extending in the seat width direction is formed between the main front portion 44 and the main portion 42 and between the main portion 42 and the main rear portion 46. Inside the groove 50, a wire (not shown) used for fixing the cushion skin 18 is arranged.

  The seat back 16 is formed of a seat cushion material formed of urethane foam. And the seat cushion 16 of this indication is applied to the seat back 16, and it arrange | positions so that a 1st area | region may become a passenger | crew side. The seat back 16 includes a pair of side support portions 56 that prevent the seated occupant's upper body from sliding in the seat width direction. The side support portions 56 are formed at both ends of the seat back 16 in the seat width direction, extend vertically, and protrude forward relative to other portions.

  Further, the seatback 16 is disposed between the pair of side support portions 56, a main upper portion 60 disposed above the main portion 58, and a lower portion relative to the main portion 58. A main lower part 62. And the main part 58 supports the passenger | crew's waist | hip | lumbar part which seated. Further, the main upper portion 60 supports the back of the seated passenger.

  Between the main upper portion 60, the main portion 58, the main lower portion 62, and the pair of side support portions 56, a groove portion 64 extending in the vertical direction is formed. A wire (not shown) used to fix the back skin 20 is disposed inside the groove portion 64.

  Further, a groove 66 extending in the sheet width direction is formed between the main upper portion 60 and the main portion 58 and between the main portion 58 and the main lower portion 62. Inside the groove 66, a wire (not shown) used for fixing the back skin 20 is disposed.

  As shown in FIG. 3, the cushion skin 18 includes a pair of side skin members 70, a front skin member 72, a main skin member 74, and a rear skin member 76. The side skin member 70 is a pair of skin members that cover the side support portion 40. The front skin member 72 is a skin member that covers the main front portion 44. The main skin member 74 is a skin member that covers the main portion 42. The rear skin member 76 is a skin member that covers the main rear portion 46.

  As shown in FIG. 3, the back skin 20 includes a pair of side skin members 80, an upper skin member 82, a main skin member 84, and a lower skin member 86. The pair of side skin members 80 that cover the side support portions 56 are a pair of skin members that cover the side support portions 56. The upper skin member 82 is a skin member that covers the main upper portion 60. The main skin member 84 is a skin member that covers the main portion 58. The lower skin member 86 is a skin member that covers the main lower portion 62. In addition, the skin member used for the cushion skin 18 and the back skin 20 is not specifically limited, What is necessary is just to use the raw material according to the objective.

  In addition, about the cushion skin 18 and the back skin 20, each skin member is connected by the surface being mutually match | combined by the end side and performing sewing etc.

  The seat of the present disclosure has been described above with reference to FIGS. 2 and 3, but the seat of the present disclosure is used not only in the front row of the vehicle but also in the second or third row of the vehicle. May be applied to the sheet.

  The seat cushion material and the seat of the present disclosure have been described in detail above, but the seat cushion material and the seat of the present disclosure are not limited to these. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present disclosure. It is understood.

  Examples will be described below, but the seat cushion material of the present disclosure is not limited to these examples. In the following description, “part” and “%” are all based on mass unless otherwise specified.

<Examples 1-5, Comparative Examples 1-5>
The materials shown in Table 1 were blended at the ratios shown in Table 1 so that the molar ratio (NCO INDEX) of (NCO groups / active hydrogen groups) was the values shown in Table 1 to prepare mixed raw materials. Thereafter, the mixed raw material was poured into a mold and molded at the mold temperature shown in Table 1 to obtain a reaction cured product of urethane foam. In addition, in the preparation process of each raw material, it carried out in nitrogen purge atmosphere.

The materials shown in Table 1 are as shown below.
PPG (A): a polyether polyol having a trifunctional number of active hydrogen groups (OH groups) and a weight average molecular weight of 6000.
Catalyst (a): Triethylenediamine.
Catalyst (b): bis (dimethylaminoethyl) ether.
MDI (E): A modified MDI-based isocyanate composed of monomeric MDI alone and a part of PPG (A).
MDI (B): A modified MDI-based isocyanate in which monomeric MDI and polymeric MDI are previously reacted with a part of PPG (A). The mixing ratio of monomeric MDI and polymeric MDI is 80/20 (monomeric MDI / polymeric MDI: mass ratio).
MDI (F): A modified MDI-based isocyanate in which monomeric MDI and polymeric MDI are previously reacted with a part of PPG (A). The mixing ratio of monomeric MDI and polymeric MDI is 40/60 (monomeric MDI / polymeric MDI: mass ratio).
MDI (G): A modified MDI-based isocyanate obtained by reacting a monomeric MDI and a polymeric MDI with a part of PPG (A) in advance. The mixing ratio of monomeric MDI and polymeric MDI is 35/65 (monomeric MDI / polymeric MDI: mass ratio).
MDI (C): MDI-based polyisocyanate prepared by blending monomeric MDI and polymeric MDI in advance at a mixing ratio of 60/40 (monomeric MDI / polymeric MDI: mass ratio).
・ TDI (D): Tolylene diisocyanate (TDI)

(Evaluation)
-Pulse NMR measurement-
The foamed urethane obtained in each example was vacuum-dried at room temperature all day and night, and a vacuum sealed tube was used as a test piece. These test pieces were measured in vacuum at 25 ± 1 ° C. according to the method described above, and the spin-spin relaxation time (T2) of the hard segment and the volume existence ratio of the hard segment were determined. In Table 1, T2 represents a spin-spin relaxation time (T2).

-Density-
The density of the urethane foam obtained in each example was measured according to JIS K 7222 (2005).

-Asker F hardness-
The surface hardness of the urethane foam obtained in each example was measured by the method described above using an ASKER hardness meter F type.

-Rebound resilience-
A 50 mm × 100 mm × 100 mm test piece was cut out from the urethane foam obtained in each example. And it measured by the method as stated above based on JISK6400-3 (2011).

-Hysteresis loss-
The hysteresis loss of the foamed urethane obtained in each example was measured by the method described above and calculated according to JIS K6400-2 (2012). For the measurement, a steel plate as shown in FIGS. 4A and 4B (dimensions; W1: 300 mm, W2: 250 mm, R1: 125 mm, R2: 30 mm, H: 50 mm) was used. .

-Logarithmic decay rate-
The logarithmic decay rate of the urethane foam obtained in each example was measured by the method described above in accordance with JIS K6900 (1994).

-Permanent compression strain-
Regarding the permanent compression set of the urethane foam obtained in each example, the wet heat compression set is the compression set after 50% compression for 22 hours under the conditions of a temperature of 50 ° C. ± 2 ° C. and a relative humidity of 95%. Measured and calculated permanent compression strain according to the method described above.

In the urethane foams obtained in Comparative Examples 1 to 5, the hard segment spin-spin relaxation time (T2) by H ¹ pulse NMR measurement under vacuum is less than 30 μsec in the first region, and the second region Then, it is less than 20 μsec. In addition, the volume existence ratios of the hard segments are all 27% or more in the first region, and all exceed 25% in the second region, which is relatively large.
Therefore, the foamed urethane obtained in Comparative Examples 1 to 5 is predicted to be a dense structure in which the urea bond aggregate structure is greatly developed. As a result, the urethane foams obtained in Comparative Examples 1 to 5 are considered to have high Asker F hardness in both the first region and the second region. Further, it is considered that the resilience is high, and hysteresis loss and compression set are high. Furthermore, the logarithmic decay rate is considered to be low.
Therefore, when the urethane foam obtained in Comparative Examples 1 to 5 is used as a vehicle seat cushion material (particularly a vehicle seat cushion material), it has a soft feel, body pressure dispersibility (fit feeling), And vibration absorption is inferior. Further, a bottom sensation and a foreign object sensation are likely to occur.
For this reason, the cushion material for seats using the urethane foam obtained by each comparative example is inferior to riding comfort.

On the other hand, the urethane foams obtained in Examples 1 to 5 have a hard segment spin-spin relaxation time (T2) measured by H ¹ pulse NMR measurement at 25 ± 1 ° C. under vacuum in the first region. 30 μsec or more and 40 μsec or less, and in the second region, the range is 20 μsec or more and less than 30 μsec. Moreover, the volume existence ratio of the hard segment in the first region and the second region is 40% or less.
Therefore, it is estimated that the urethane foam obtained in Examples 1 to 5 has a structure in which the aggregate structure of urea bonds is suppressed to a small amount. As a result, the urethane foams obtained in Examples 1 to 5 have particularly low Asker F hardness in the first region arranged on the passenger side, and Asker F hardness in the first region and the second region. The absolute value of the difference is considered to be large. Further, it is considered that the rebound resilience is lower than each comparative example, and the hysteresis loss and compression set are lower. Furthermore, the logarithmic decay rate is considered to be higher than in each comparative example.
Therefore, when the urethane foam obtained in each example is used as a cushion material for a seat for a vehicle (especially a cushion material for a seat for a vehicle), it has a soft feel, a body pressure dispersibility (fit feeling), and vibration. Excellent absorbency. In addition, bottom sensation and foreign object sensation are suppressed.
As described above, the seat cushion material using the urethane foam obtained in each example is superior in ride comfort than the conventional seat cushion material.

100 seat cushion material, 102 1st area, 104 2nd area, 200 seats, 202 seat part, 204 backrest part

Claims (7)

It is a reaction cured product formed using the isocyanate component of diphenylmethane diisocyanate compound, and has a urethane foam containing a hard segment and a soft segment,
The urethane foam has a hard segment spin-spin relaxation time (T2) of 30 μsec or more and 40 μsec or less and a hard segment volume existence ratio of 10% or more and 40% or less in H ¹ solid-state pulse NMR measurement. Area,
In the H ¹ solid-state pulse NMR measurement, a second region in which the spin-spin relaxation time (T2) of the hard segment is 20 μsec or more and less than 30 μsec, and the volume ratio of the hard segment is 5% or more and 40% or less, A second region adjacent to the first region;
A cushioning material for seats.   The seat cushion material according to claim 1, wherein the Asker F hardness in the first region is 20 or more and less than 50, and the Asker F hardness in the second region is 50 or more and 70 or less.   The absolute value of the difference between the F1 and the F2 is 10 or more and 50 or less, where the Asker F hardness in the first region is F1 and the Asker F hardness in the second region is F2. Cushion material for seats.   The seat according to any one of claims 1 to 3, wherein the isocyanate component includes an isocyanate-terminated polyisocyanate reacted with a mixture of monomeric diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate and a part of the polyol component. Cushion material.   The seat cushion material according to any one of claims 1 to 4, wherein the seat cushion material is used for a vehicle.   The seat cushion material according to any one of claims 1 to 5, wherein the seat cushion material is used for a vehicle. A seat that supports the buttocks of the seated occupant;
A backrest that supports the back and waist of the seated occupant;
With
At least one of the seat part and the backrest part is a seat having the seat cushion material according to claim 1.