JP6214129B2 - Manufacturing method of different hardness mold foam - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for producing a different hardness mold foam used for railway vehicles, automobiles, and aircraft.

  Soft urethane foam is used for railway vehicles, automobiles, and the like because of its cushioning properties, and is required to be comfortable for the seated person. For example, in consideration of sitting for a long time, the seat cushion has a role of preventing the lateral movement of the body by forming both sides (both side portions) of the seat in a convex shape. Further, a different hardness mold foam is known in which a portion (center portion) where the body hits the inner side from both side portions is soft and both side portions are hard. This is to prevent the body from shaking and to prevent settling caused by a person's well grasping, for example, in a railcar seat.

  Conventionally, in order to prevent shaking and settling of the body, a method of applying a built-in metal frame or attaching a plate-like slab to a portion to be hardened is known. However, this requires a lot of work and a lot of work and time for repairs when the metal frame is displaced. In addition, as in Patent Document 1, two mixing heads, a soft injection head and a hard injection head, are used, and the tolylene diisocyanate (TDI) index, the number of water parts, and the number of parts of the catalyst are in different hardness parts. There is also known a method in which different foaming liquid mixtures are discharged and integrally foamed. However, in this case, the change width of the hardness is as narrow as 17 at the maximum, and a wide change width is desired.

  Patent Literature 2 and Patent Literature 3 disclose that different hardness molded foams are obtained using various raw materials. However, in the case of Patent Documents 2 and 3, the adjustment of the raw materials is complicated, and the flame retardancy also changes due to the change of the polyol, so that it is suitable for those requiring high flame retardancy such as a railway vehicle. Absent. For this reason, in order to guarantee the flame retardancy of the whole molded foam having different hardness, further measures such as adjustment of raw materials are required.

  Further, in recent years, the required physical properties of different hardness mold foams, mainly density, hardness, and impact resilience, are in a wide range. Therefore, foams obtained by the above method have a limit to cope with them.

JP-A-62-240091 JP 09-136940 A JP 2002-212254 A

  The present invention has been made in view of the above, and provides a method for producing a different hardness mold foam that enables a wide range of physical properties to be set and a different hardness mold foam that can maintain flame retardancy by a simple method. The purpose is to do.

The method for producing a different hardness mold foam of the present invention is a method for producing a different hardness mold foam used for a seat cushion for a railway vehicle, automobile or aircraft, wherein the hardness of both side portions is higher than the hardness of the central portion . at least one polyol component, and two types of a first foamed mixture obtained by one of the isocyanate component by mixing of the isocyanate component, wherein the at least one polyol component, and, two of the isocyanate component The second foaming mixture obtained by mixing the other isocyanate component of the two is separately injected into the mold from the same mixing head, and then integrally foamed. The two types of isocyanate components are: Both are mixtures of tolylene diisocyanate and diphenylmethane diisocyanate (MDI) Characterized by Rukoto different proportions of tolylene diisocyanate and diphenylmethane diisocyanate with each other.

  According to the present invention, it is possible to obtain a different hardness mold foam which can set a wider range of physical properties than before and can maintain flame retardancy by simply changing only the isocyanate component.

Explanatory drawing of the different hardness mold foam and molding die concerning this invention. Explanatory drawing which shows the example of supply of the polyol component and isocyanate component with respect to the mixing head which concerns on this invention.

Hereinafter, the manufacturing method of the different hardness mold foam which concerns on this invention is demonstrated.
In the present invention, the different hardness means that there are parts having different hardness in one foam. In the different hardness mold foam of the present invention, two types of foamed mixed liquid obtained by mixing at least one type of polyol component and two types of isocyanate component are separately discharged from the same mixing head into a molding die. , Obtained by integral foam molding.

In the present invention, the polyol component is already mixed with raw materials other than the first and second isocyanate components described later. As the polyol, polyols and polymer polyols used for HR molds can be used. Here, the first isocyanate component comprises 0-30% diphenylmethane diisocyanate (MDI) and 70-100% tolylene diisocyanate (TDI), and the second isocyanate component comprises 70-100% MDI and 0-30% TDI. It is preferable to include.

In the present invention, a chemical foaming agent is preferably used as the foaming agent, and water is preferably used. Water reacts with the isocyanate component and generates a reaction gas to foam the urethane resin.
In the present invention, a conventionally known catalyst can be used without particular limitation as the catalyst. For example, triethylenediamine, bis (dimethylaminoethyl) ether, dibutyltin laurate and the like can be used, and these may be used alone or in combination.

  In the present invention, it is preferable to use a silicone-based foam stabilizer. Moreover, in this invention, you may use a crosslinking agent, an additive, etc. in the range which does not affect the objective of this invention. In particular, flame retardants such as melamine type and halogen type may be used in railcar and aircraft cushion bodies.

  Next, a case of producing a different hardness mold foam used for an automobile seat cushion in which the hardness of both side portions is higher than the hardness of the central portion will be described with reference to FIGS. Here, FIG. 1 is an explanatory view of a mold having a different hardness and a molding die, and FIG. 2 is an explanatory view showing an example of supplying a polyol component and an isocyanate component to a mixing head.

  Reference numeral 1 in FIG. 1 indicates a different hardness mold foam composed of a central portion 2 where a main body part hits and a convex side portion 3 having a higher hardness than the central portion 2. Moreover, the code | symbol 4 in a figure shows the shaping | molding die provided with the lower die 5 and the upper die 6 which were adjusted to appropriate temperature.

  Reference numeral 11 in FIG. 2 indicates a mixing head having six raw material supply ports 12a, 12b, 12c, 12d, 12e, and 12f. Here, the raw material supply ports 12a to 12d are for polyol components A to D, and the raw material supply ports 12e and 12f are for isocyanate components A and B described later. In the conventional two-liquid mixing type, a mixing head for each different foaming liquid is required, and a place and cost are required.

  First, a first foaming mixture obtained by mixing a predetermined polyol component (for example, polyol component A) and an isocyanate component (for example, isocyanate component A) in a state where the upper mold 6 is opened is used as a molding metal in FIG. It discharges to the center part 5a of the lower mold 5 of the mold 4. Next, the second foaming mixture obtained by mixing the polyol component A and the isocyanate component B is rapidly discharged into the recess 5 b of the lower mold 5 continuously. Subsequently, the upper mold 6 is closed and integrally foamed to produce the different hardness mold foam 1. In addition, the discharge order of the foaming liquid mixture with respect to the center part of a lower metal mold | die, a recessed part, and the operation | movement trajectory of a mixing head can be set suitably.

Next, specific examples and comparative examples of the present invention will be described.
(Example)
The different hardness mold foam of FIG. 1 is manufactured as follows using a molding die and the mixing head of FIG. However, the present embodiment is not limited to the following example. In this example, the case where the polyol component A and the isocyanate components A and B are reacted is described.

(Polyol component A)
Polyol: A polyether polyol having a hydroxyl value of 28 and a functional group number of 3.
Polymer polyol: a polyether polyol having a hydroxyl value of 28 and a functional group number of 3
Foaming agent: water
Catalyst 1: TEDA (triethylenediamine)
Catalyst 2: DMAEE (dimethylaminoethyl ether)
Foam stabilizer : silicone
Communicating agent: polyether polyol having a hydroxyl value of 51
Cross-linking agent: polyether polyol having a hydroxyl value of 840
(Isocyanate component A): polyisocyanate containing 20% MDI and 80% TDI
(Isocyanate component B): Polyisocyanate containing 73% MDI and 27% TDI.

  Next, the manufacturing method of a different hardness mold foam is demonstrated. In addition, two types of foaming liquid mixture, a mixed liquid of polyol component A and isocyanate component A (first foaming liquid mixture), and a mixed liquid of polyol component A and isocyanate component B (second foaming liquid mixture) are shown in the following table. Mix as in 1. Here, Table 1 also discloses Index, core density, hardness, impact resilience, and wet heat compression residual strain. Subsequently, the first foamed mixed liquid is discharged from the mixing head 11 to the central part 5 a of the lower mold 5 of the molding mold 4. Subsequently, the second foamed mixed liquid is rapidly discharged from the same mixing head 11 to the concave portion 5 b of the lower mold 5. Thereafter, the upper mold 6 is closed and integrally foamed to produce the different hardness mold foam 1.

(Comparative example)
Using the polyol component A blended as shown in Table 1 below, two types of a foaming stock solution with only the index changed are continuously discharged from the same mixing head into the lower mold of the mold, and the different hardness mold Formed a foam. At this time, the first foamed mixed liquid of Index 90 was discharged to the central part 5 a of the lower mold 5, and the second foamed mixed liquid of Index 100 was continuously discharged to the concave part 5 b of the lower mold 5.

  In addition, said Index shows the equivalent ratio (isocyanate group / active hydroxyl group) of the isocyanate group in a polyisocyanate compound with respect to all the active hydroxyl groups in a polyol component. Here, when all polyols and water (active hydroxyl group) react with isocyanate (isocyanate group), Index = 100. Moreover, when Index is high, there are more isocyanate groups than active hydroxyl groups.

Each physical property of Table 1 was measured as follows.
Core density (kg / m ³ ): According to JIS K-6400-1: 2004.
Hardness (N / 314 cm ² ): According to JIS K-6400-2, Method D: 2004.
Rebound resilience (%): According to JIS K-6400-3: 2011.
Wet heat residual strain ratio (%): According to JIS K-6400-4: 2004.

Only partial and hardness 136.8N / 314cm ² parts hardness 117.5N / 314cm ² is obtained in the comparative example. In contrast, in the embodiment, 2 kinds of the foaming mixture with Index90, hardness 118.7N / 314cm ² parts and hardness 288.3N / 314cm ² parts is obtained. If the indexes of the two types of foaming mixture are different, a wider physical property range can be obtained. Moreover, the polyol component mix | blended so that the ranges other than the different hardness obtained from the polyol component A and the isocyanate components A and B can be respectively used for the raw material supply ports 12b-12d for the polyol component of a mixing head. From this, it can be seen that the range of physical properties that can be set in one form is wider in the example. Furthermore, the types of different hardness foams obtained can also be increased over conventional manufacturing methods.

Table 2 shows the core density, hardness, impact resilience, and wet heat compression residual strain of the foam obtained when isocyanate components A and B are used, respectively.

Each physical property range that can be set by the foamed mixed liquid obtained from each of the polyol component A and the isocyanate component A, and the polyol component A and the isocyanate component B is shown, and Index is adjusted from 90 to 105. For example, when obtaining a different hardness foam in which the hardness difference between the high hardness part and the low hardness part is maximized, a foam having a hardness of 115 N / 314 cm ² composed of polyol component A and isocyanate component A, and polyol component A and isocyanate component B are used. The foam having a hardness of 570 N / 314 cm ² can be integrally foamed.

In the above embodiment, the case where one kind of polyol component is used has been described. However, when four kinds of polyol components A to D are used, a wide range of physical properties of density 25 to 120 kg / m ³ and hardness 80 to 400 N are used. It was found that can be combined as appropriate.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

  The different hardness mold foam of the present invention can be used for an automotive seat cushion material having high hardness on both side portions and good supportability. In addition, since a molded foam having a different hardness can be obtained while maintaining flame retardancy, it is suitable for a cushion material for railway vehicles and aircraft in which flame retardancy is particularly important.

  DESCRIPTION OF SYMBOLS 1 ... Molding die, 2 ... Center part, 3 ... Side part, 4 ... Molding die, 5 ... Lower die, 6 ... Upper die, 11 ... Mixing head, 12a-12f ... Raw material supply port.

Claims (3)

In the method of manufacturing a different hardness mold foam used for a seat cushion for a railway vehicle, automobile or aircraft, the hardness of both side parts is higher than the hardness of the central part ,
At least one polyol component, and two types of a first foamed mixture obtained by one of the isocyanate component by mixing of the isocyanate component, wherein the at least one polyol component, and, two of the isocyanate component And the second foaming mixture obtained by mixing the other isocyanate component of the two, separately injected into the mold from the same mixing head, then integrally foamed,
The two kinds of the isocyanate component are both mixtures of tolylene diisocyanate and diphenylmethane diisocyanate (MDI), a manufacturing method of different hardness molded foam ratio of tolylene diisocyanate and diphenylmethane diisocyanate, wherein Rukoto different from each other. The ratio is such that the change in hardness between the parts of the mold foam obtained by molding the first foamed mixture and the mold foam obtained by molding the second foamed mixture is 17 N / 314 cm. ² The method for producing a different hardness mold foam according to claim 1, wherein the ratio is such that the ratio exceeds. The two kinds of isocyanate components include a first isocyanate component containing 0 to 30% by weight of diphenylmethane diisocyanate and 70 to 100% by weight of tolylene diisocyanate, 70 to 100% by weight of diphenylmethane diisocyanate and 0 to 30% by weight of tolylene diisocyanate. Comprising a second isocyanate component (provided that the first isocyanate component is 0% by weight diphenylmethane diisocyanate and 100% by weight tolylene diisocyanate, and the second isocyanate component is 100% by weight diphenylmethane diisocyanate and 3. Except for the case of 0% by weight of diisocyanate.) The process for producing a molded foam of different hardness according to claim 1 or 2.

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