JPH05320304A - Production of polyurethane foam for seat cushioning improved in comfortableness to ride - Google Patents

Abstract

PURPOSE:To produce a polyurethane foam for seat cushionings improved in comfortableness to ride by reacting a polyol component containing a specific secondary aromatic amine blended therein with a polyisocyanate component. CONSTITUTION:The polyurethane foam is obtained by reacting (A) a polyol component prepared by blending (A1) 100 pts.wt. polyol such as a bi- to a trivalent polyoxypropylene polyol having preferably 20-65 hydroxyl value with (A2) 0.5-5 pts.wt., preferably 0.5-2.5 pts.wt. secondary aromatic amine of the formula (R and R' are 1-3C alkyl) [e.g. 4,4'-bis-(methylamino-diphenylmethane)], (A3) a catalyst and (A4) a foaming agent (preferably water or its mixture with a small amount of a substitute fluorocarbon added thereto) and, as necessary, other additives blended therein with (B) a polyisocyanate component (e.g. tolylene diisocyanate (TDI) or polymeric cyanate). This polyurethane foam has softness, degrees of sinking and bouncing and characteristics of vibration and comfortableness to ride suitable as seat cushionings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyurethane foam for a seat cushion having improved riding comfort.

[0002]

2. Description of the Related Art In recent years, along with the development of the automobile industry, not only the functionality of a vehicle has been improved, but also the interior of a vehicle has been upgraded and the comfortability has been improved / improved. In particular, from the viewpoint of improving the riding comfort, there is a strong demand for the development of a polyurethane foam for seats having more excellent cushioning properties.

The cushion characteristic of the seat is one of the factors for evaluating the riding comfort of the seat, and the following points are generally pointed out as the static and dynamic characteristics that are the indexes. The larger the amount of deflection obtained by the load test, the better. However, if the amount of deflection is too large, the hips and lumbar vertebrae are overly submerged, and a feeling of bottoming is likely to occur, which is not preferable. The smaller the static spring constant, the better. In particular, the slope of the pressure side curve at the time of deflection of 75% is an index for evaluating the feeling of bottoming, and the smaller this is, the better. It is better that the resonance vibration frequency and vibration transmissibility obtained in the vibration test are smaller. That is, 80% of the vibration riding comfort is vibration transmitted through the seat, and improvement of the transmission characteristics of these seats is considered to be an important factor for improving riding comfort.

From the above viewpoint, it can be said that in order to design a seat cushion that is totally comfortable to ride, it is necessary to combine the above factors in a well-balanced manner while maintaining the density and hardness required for the seat. ..

By the way, the conventional polyurethane foam for seat cushion is a hot mold foam (hereinafter, referred to as HOT).
Abbreviated as form. ) And cold mold foam (hereinafter abbreviated as HR foam). Regarding the amount of deflection and hysteresis loss, HOT foam is generally larger than HR foam and is superior in terms of sinking and bouncing, but there is a feeling of bottoming and HR foam is another index for resonance vibration frequency. It is larger and inferior in transfer characteristics. On the other hand, the HR foam is generally superior to the HOT foam at the resonance vibration frequency, but has a high vibration transmissibility at the resonance point, and is hard and easy to bounce.

As described above, none of the conventional foams satisfies the above-mentioned factors, which are said to be indicators of cushioning characteristics, in a well-balanced manner, and therefore, by itself, it is a polyurethane foam for a seat cushion that is totally comfortable to ride. Was desired to be developed.

[0007]

The present invention, by itself, has a cushioning property suitable as a polyurethane foam for a seat cushion, that is, a degree of sinking, a softness, and a degree of bounce, and a polyurethane foam having excellent dynamic vibration characteristics. It aims at providing the manufacturing method of.

[0008]

[Means for Solving the Problems] As a result of intensive research conducted by the present inventors, in order to achieve the above object, as a composition for forming polyurethane foam, a specific secondary aromatic compound is contained in its polyol component. It has been found that the above object can be achieved by using a product to which a small amount of amine has been added and blended, and the present invention has been completed.

That is, the present invention relates to a method for producing a polyurethane foam by reacting a polyol component composed of a polyol, a catalyst, a foaming agent, and other additives with a polyisocyanate component. 0.5 to 100 parts by weight of the polyether polyol in the above polyol component.
The present invention relates to a method for producing a polyurethane foam for a seat cushion having an improved riding comfort, which is characterized by using 5 parts by weight. It should be noted that this method can be particularly suitably used for producing a polyurethane foam for a seat cushion of this kind by a hot molding process.

As the polyol used in the present invention, all general-purpose polyether polyols, polymer polyols and the like can be used, but the hydroxyl value is preferably from 20 to 20.
The polyoxypropylene polyol or the polyoxyethylene propylene polyol having a valency of 65 in the range of 65 may be used alone or in combination. As the polyisocyanate component, all known at least bifunctional polyisocyanates can be used,
For example, TDI, TODI, NDI, XDI, PAPI,
Polymeric isocyanate or the like can be used alone or in combination. Further, a prepolymer or a semiprepolymer obtained by adding a polyol can also be used.

In the present invention, when a polyurethane foam is produced by reacting a polyol component and a polyisocyanate component, the isocyanate index is preferably adjusted within the range of 90 to 110 based on desired foam characteristics.

Further, as the catalyst and the foaming agent, all the known ones for mold foams can be used. Especially, the latter is foamed by adding water or a small amount of CFC substitute to water from the viewpoint of global environment protection. Agent systems are preferred.

Other known foam stabilizers for mold foams, flame retardants, fillers, pigments and the like may be used as required.

In the present invention, the secondary aromatic amine represented by the above general formula is added in an amount of 0.5 to 5 parts by weight, preferably 0.5 to 2.5 parts by weight, per 100 parts by weight of the polyol. To use. These secondary aromatic amines exert a remarkable effect in improving the cushioning characteristics of the foam as described later.

Specific examples of the secondary aromatic amines include 4,4'-bis- (methylamino) -diphenylmethane, 4,4'-bis- (ethylamino) -diphenylmethane and 4-methylamino-. 4'-ethylamino-diphenylmethane, 4-methylamino-4'-n-propylamino-diphenylmethane and the like can be mentioned.

When the carbon number of R and R'is 4 or more, the reaction rate becomes slow due to steric hindrance of the alkyl group, which is not preferable. These cross-linking agents can be used alone or in combination. If the addition amount is less than 0.5 parts by weight, the effect of addition is significantly reduced, and if it is 5 parts by weight or more, the balance of foam characteristics is lost, and for example, vibration characteristics are improved while maintaining other characteristic levels required for a seat cushion. The initial goal of doing is not achieved.

[0017]

The present invention has the second characteristic of the raw material polyol component.
Since a high-grade aromatic amine is added and used, both cushioning properties and dynamic vibration characteristics, which could not be achieved with conventional HOT foams and HR foams, can be provided in a well-balanced manner, and this polyurethane foam is used alone. Also in the case of doing, a seat cushion with improved riding comfort can be obtained. Further, the conventional molding process, especially the hot molding process can be applied as it is, which is economically advantageous.

[0018]

EXAMPLES The present invention will be specifically described below based on examples. Using the raw material components (unit: parts by weight) shown in Table 1, a seat cushion pad for an operator and a test piece for characteristic evaluation were produced. Particularly in the former case, the polyol component A and the polyisocyanate component B are supplied to the mixing head according to the hot molding process, injected from the discharge nozzle into the lower mold of the foaming mold set at about 35 ° C., and the upper mold is closed. After passing through a heating oven at about 100 ° C. for 10 minutes, the mold temperature was then cooled to about 45 ° C. and the mold was removed to obtain an automobile seat cushion pad. Next, in order to evaluate the properties of this polyuren foam for seat cushion, a test piece was molded using a 400x400x100t fixed-length mold, and this test piece was manufactured by JAS.
Each property was measured according to OB-407 and 408. The results are shown in Table 1 and FIG. 1 together with the comparative example (HOT foam).
3 shows. In addition, the measurement result regarding a typical HR foam is additionally shown in FIGS.

As is clear from Table 1, the polyurethane foam obtained by the method of the present invention has a larger hysteresis loss than the HOT foam shown as a comparative example (it is hard to bounce) and has high energy absorption. Be done. This is also clear from the free vibration curve (FIG. 2), and the free restitution rate of the foam of the present invention obtained from this curve diagram is 3.1%, which is the free restitution rate of the conventional foam (HOT foam 14). 0.5%, HR foam 59.6%), which shows extremely low resilience performance.

FIG. 1 is a load-deflection curve diagram of each foam, in which 1 is the foam of the present invention and 2 is a conventional type H
OT foam and 3 relate to HR foam.
In this figure, the slopes (θ ₁ and θ ₂ ) of the pressurizing side curve when Form 1 and Form 2 are deflected by 75% are θ ₁ <
The size of θ ₂ and foam 1 are smaller, and in the present invention, the one having an improved feeling of bottoming is obtained as compared with the conventional hot mold foam. The hysteresis loss in Table 1 is a value obtained by the usual method from FIG.

Further, as shown in FIG. 3, the foam of the present invention is characterized in that the vibration transmissibility is suppressed to be lower than that of the conventional foam in the frequency range of 3 to 5 Hz, and the peak due to resonance does not appear. It can be said that the foam has remarkably improved comfort characteristics.

[0022]

[Table 1]

[0023]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, compared with the conventional HOT foam (hot mold foam), although it has almost the same density and deflection amount, it has less feeling of bottoming and low resilience. The present invention provides a method for easily manufacturing a polyurethane foam for a seat cushion, which exhibits excellent properties and has significantly improved vibration riding comfort characteristics, by a conventional molding process, particularly a hot molding process.

[Brief description of drawings]

FIG. 1 Foams of the invention and conventional H shown in the examples.
The load-deflection curve figure of OT foam and HR foam.

[Fig. 2] Free vibration curve (free repulsion rate) of each form above
Fig.

FIG. 3 is a vibration characteristic diagram of each foam.

[Explanation of symbols]

θ ₁ , θ ₂ ...... Inclination of the tangent line drawn by the pressure side curve when the load-deflection curve is deflected by 75%

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Claims (1)

[Claims] 1. A method for producing a polyurethane foam by reacting a polyol component comprising a polyol, a catalyst, a foaming agent, and other additives with a polyisocyanate component, wherein A polyurethane foam for a seat cushion with improved riding comfort, characterized in that 0.5 to 5 parts by weight of a secondary aromatic amine represented by the above is blended per 100 parts by weight of the polyol in the polyol component. Production method.