JP4532161B2 - Polyurethane foam and headrest for headrest - Google Patents

Description

  The present invention relates to a headrest polyurethane foam and a headrest, for example, which are attached to an upper end portion of a seat in an automobile and are loaded inside a headrest for reducing an impact on an occupant's head.

Generally, a headrest attached to an upper end portion of a seat in an automobile is configured by including a polyurethane foam in a state where the headrest stay is inserted into a bag-like skin. The headrest stay used here is configured by applying a chrome plating after a round bar formed of a steel material is bent at a predetermined position and formed into an inverted U shape, for example. As a polyurethane foam included in the skin, a flexible polyurethane foam obtained by reacting an active hydrogen compound and an organic polyisocyanate and foaming with a foaming agent is known (for example, see Patent Document 1). Specifically, the active hydrogen compound is a polyether triol having a hydroxyl equivalent of 900 to 1500 and containing 5 to 30% by weight of ethylene oxide units at the terminal, and a hydroxyl equivalent of 1010 to 1500 and 5 to 30 ethylene oxide units at the terminal. What is blended in a predetermined ratio with polyether diol containing by weight is used.
JP-A-11-130833 (pages 2 and 3)

  By the way, in the case of an export headrest stay or the like, it is plated and exported in the state of a round bar that is not bent for the convenience of transportation, and is used after being bent locally. In such a case, since the bent part of the headrest stay is used after being plated, fine cracks enter the plating of the bent part, and such fine cracks corrode the headrest stay. It causes to cause. Furthermore, there is a problem that the adhesiveness of the polyurethane foam to the bent portion of the headrest stay is lowered.

The flexible polyurethane foam described in Patent Document 1 is intended to effectively absorb the impact and to fully exhibit the function as a headrest. In order to achieve such an object, the raw material composition of the polyurethane foam is set as described above so that the resilience modulus is 30% or less and the temperature dependence of the compression load is 0.030 kg / cm ² . However, since this raw material composition is not particularly associated with the catalyst, the polyurethane foam has insufficient adhesion to the headrest stay, and the reactivity between the polyol and the polyisocyanate is insufficient, and the polyurethane foam may be torn or sink. was there. In that case, a gap is generated between the headrest stay and the polyurethane foam, which leads to the cause of the headrest stay being exposed to the outside air and causing corrosion at the bent portion. Such a problem does not become a problem when plating is performed after the headrest stay is bent, but may be a problem when bending is performed after the headrest stay is plated.

  The present invention has been made paying attention to such problems existing in the prior art. The purpose is to improve the adhesion of polyurethane foam to the bent part when the headrest stay is bent after plating, and to suppress the corrosion of the bent part of the headrest stay. It is an object of the present invention to provide a polyurethane foam for a headrest and a headrest.

  In order to achieve the above object, the polyurethane foam for a headrest according to the first aspect of the present invention is a polyurethane foam for forming a headrest by being encapsulated in a state in which a headrest stay is inserted into a bag-like skin. The headrest stay is bent after the surface of the metal material is plated, and the bent portion is located in the headrest, and a polyurethane foam manufacturing raw material is used to prevent the occurrence of corrosion in the bent portion. At least a polyether polyol, a polyisocyanate, a catalyst for accelerating their reaction, and a blowing agent, wherein the polyether polyol is a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, Contains 20 mol% or more of ethylene oxide units Are those, the catalyst comprises a reaction of the catalyst and non-reactive catalyst and polyisocyanate, it is characterized in that the non-reactive catalyst is a compound having a volatility.

  A polyurethane foam for a headrest according to a second aspect of the present invention is a polyurethane foam for forming a headrest by being included in a state where the headrest stay is inserted into a bag-shaped skin, wherein the headrest stay is a surface of a metal material. In order to prevent the occurrence of corrosion in the bent portion, the polyurethane foam production raw material is polyether polyol, polyisocyanate, and their components. It contains at least a catalyst for promoting the reaction and a foaming agent, and the polyether polyol is a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, and contains 10 to 20 mol% of polyethylene oxide units. And the catalyst is poly It includes a cyanate-reactive catalyst and non-reactive catalyst, and in which non-reactive catalyst is characterized more becomes possible with a highly volatile compound having low volatile compounds.

  A headrest according to a third aspect of the present invention is characterized in that the headrest polyurethane foam according to the first or second aspect is contained in a state in which the headrest stay is inserted into a bag-shaped skin. It is.

According to the present invention, the following effects can be exhibited.
The polyurethane foam for a headrest according to claim 1 is composed of a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol in a polyether polyol, and contains 20 mol% or more of polyethylene oxide units. . For this reason, the polyurethane foam contains more hydroxyl groups than ordinary polyurethane foam having 10 to 20 mol% of polyethylene oxide units, which increases the binding force to the headrest stay and increases the reactivity with the polyisocyanate. It is done. Therefore, when the headrest stay is bent after plating, the adhesion of the polyurethane foam to the bent portion of the headrest stay can be improved.

  Moreover, a catalyst reactive with polyisocyanate and a non-reactive and volatile catalyst with polyisocyanate are used as the catalyst. For this reason, it is thought that the reactivity of polyether polyol and polyisocyanate is improved. Accordingly, tearing or sinking of the polyurethane foam is suppressed, the headrest stay is not exposed to the outside air, moisture can be prevented from entering, and oxidation on the headrest stay surface is prevented. As a result, when the headrest stay is bent after plating, it is possible to suppress corrosion at the bent portion. Furthermore, the catalyst after the reaction between the polyether polyether and the polyisocyanate is either incorporated into the polyurethane foam or volatilizes and does not remain. Therefore, it is possible to suppress the occurrence of corrosion based on the catalyst at the bent portion of the headrest stay.

  As mentioned above, since polyurethane foam is closely attached to the headrest stay, the formation of a gap between them is suppressed and contact with the outside air is blocked, and at the same time, polyurethane foam is not torn or sinked. It is thought that the introduction of outside air to the stay will be avoided. As a result, when the headrest stay is bent after plating, it is possible to suppress corrosion at the bent portion.

  The polyurethane foam for a headrest according to claim 2 has a polyethylene oxide unit content of 10 to 20 mol% in the polyether polyol, but contains a highly volatile compound as a non-reactive catalyst. Yes. For this reason, the reactivity of polyether polyol and polyisocyanate can be improved, without leaving a catalyst in a polyurethane foam. Therefore, the same effect as that of the invention according to claim 1 can be exhibited.

  According to the invention described in claim 3, the action and effect of the invention of the polyurethane foam according to claim 1 or claim 2 can be exhibited in the headrest.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the skin 12 constituting the headrest 11 of the present embodiment is formed so as to form a bag as a whole, and a slit-like opening 13 is provided at the center of the bottom surface, and the opening Stay holes 14 are formed at both end positions of 13. Inside the skin 12, a base end portion of a headrest stay 15 made of a metal material such as steel is inserted, and both leg portions protrude outward from the stay hole 14. A polyurethane foam 16 is enclosed inside the skin 12 with a headrest stay 15 inserted. The headrest stay 15 includes a pair of first bent portions 15a bent at a right angle in the inner back portion of the skin 12 and a pair of second bent portions 15b bent at an obtuse angle on the stay hole 14 side. Have.

  The headrest stay 15 was formed by bending a pair of first bent portions 15a and a pair of second bent portions 15b when the headrest 11 was manufactured after the steel round bar surface was plated with chrome. Is. Therefore, in these first bent portion 15a and second bent portion 15b, microcracks are likely to enter the chromium plating film, and corrosion (rust) tends to occur from these portions.

  In the inserted state of the headrest stay 15, the raw material (liquid) of the polyurethane foam 16 injected from the opening 13 is reacted inside the skin 12, and foamed and expanded to form the entire headrest 11 into a pillow shape. Yes. Here, the headrest 11 is formed in a concavely curved shape as a whole so that the front portion contacting the occupant's head bulges in the left and right ends in a horizontal section.

  The outer skin 12 is made of, for example, a film laminating method comprising an outer leather skin 12a made of, for example, genuine leather or synthetic leather, an elastic slab 12b made of polyurethane foam joined and disposed on the entire inside, and a resin film 12c made of polyurethane or the like. It is constituted by being laminated.

  And when manufacturing this headrest 11, the following methods are taken. That is, after the laminated body for producing the skin 12 is formed into a bag shape by bending it into a three-dimensional shape and sewing it, the front and back are reversed from the opening 13 to produce the bag-like skin 12. Subsequently, the headrest stay 15 is inserted into the skin 12, and in this state, the skin 12 is turned upside down and set in a mold (not shown). The headrest stay 15 is obtained by applying a chromium plating to the surface of a steel round bar, bending it in an inverted U shape, and bending the upper both sides obliquely rearward.

  And the manufacturing raw material which makes the liquid form of the polyurethane foam 16 from the opening part 13 is inject | poured into the inside of the skin 12, and a foam, expansion is carried out simultaneously with making a polyol, polyisocyanate, etc. react. Thereby, the skin 12 and the headrest stay 15 are integrated with the molding layer of the polyurethane foam 16, and the headrest 11 is manufactured.

  The raw material for producing the polyurethane foam is composed of polyol, polyisocyanate, catalyst, foaming agent, foam stabilizer and the like. And a polyurethane foam is obtained by making a polyol and polyisocyanate react with presence of a catalyst, a foaming agent, etc., and making it foam. As the polyol, polyether polyol is used because it is excellent in reactivity with polyisocyanate and does not hydrolyze like polyester polyol.

  As the polyether polyol, a polyether polyol composed of a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, a modified product thereof, and the like are used. Examples of the modified product include those obtained by adding acrylonitrile or styrene to the polyether polyol, or those obtained by adding both acrylonitrile and styrene. Here, the polyhydric alcohol is a compound having a plurality of hydroxyl groups in one molecule. Examples of the polyhydric alcohol include glycerin and dipropylene glycol.

  Specific examples of polyether polyols include triols obtained by addition polymerization of propylene oxide to glycerin and addition polymerization of ethylene oxide, and diols obtained by addition polymerization of propylene oxide to dipropylene glycol and addition polymerization of ethylene oxide. . Since these polyether polyols have a primary hydroxyl group at the terminal, the reactivity with the polyisocyanate is high. The average molecular weight of the polyether polyol is preferably 2000 to 6000. When the average molecular weight is less than 2000, the foam molding stability of the obtained polyurethane is remarkably lowered, and when it exceeds 6000, the resilience of the polyurethane foam is remarkably increased and the cushioning property, that is, the energy absorption rate is lowered.

  The polyethylene oxide unit in the polyether polyol is 20 mol% or more. In this case, the polyether polyol contains more hydroxyl groups than a normal polyurethane foam having 10 to 20 mol% of polyethylene oxide units, increasing the binding force to the headrest stay 15 and high reactivity with the polyisocyanate. Become. Therefore, in the case where the headrest stay 15 is bent after plating, the adhesion of the polyurethane foam 16 to the bent portion of the headrest stay 15, that is, the first bent portion 15a and the second bent portion 15b can be improved. At the same time, the occurrence of corrosion in the bent portions can be suppressed. This polyol can change the number of functional groups and the hydroxyl value of the hydroxyl group by adjusting the type, molecular weight, condensation degree, and the like of the raw material components.

  Next, the polyisocyanate to be reacted with the polyether polyol is a compound having a plurality of isocyanate groups, specifically, tolylene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate ( NDI), triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), and modified products thereof.

  The isocyanate index of the polyisocyanate may be 100 or less or more than 100, but is usually in the range of about 70 to 140. Here, the isocyanate index represents the ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyol and water as a blowing agent in percentage.

  The catalyst is for accelerating the urethanization reaction between polyether polyol and polyisocyanate. Such catalysts include dimethylethanolamine (DMEA), triethylenediamine (TEDA), 1- (dimethylaminoethyl) -4-methylpiperazine, bis (2-dimethylaminoethyl) ether, N, N-dimethylamino-ethylmorpholine. And amine compounds such as N-methylmorpholine and N-ethylmorpholine.

  Dimethylethanolamine (boiling point 134 ° C.) is a catalyst that reacts with polyisocyanate and is incorporated into the polyurethane foam 16. Therefore, it is considered that such a catalyst can improve adhesion to a metal by its hydroxyl group without affecting the corrosion of the headrest stay 15.

  Triethylenediamine (boiling point 174 ° C., vapor pressure 2 mmHg / 20 ° C.), 1- (dimethylaminoethyl) -4-methylpiperazine (vapor pressure 0.1 mmHg / 20 ° C.), bis (2-dimethylaminoethyl) ether, etc. A catalyst that does not react with the polyisocyanate and is not incorporated into the polyurethane foam 16. Therefore, there is a possibility of affecting the corrosion of the headrest stay 15, but since it has volatility, it volatilizes and does not remain after fulfilling its function as a catalyst.

  Morpholines such as N, N-dimethylamino-ethylmorpholine (vapor pressure 3 mmHg / 20 ° C.), N-ethylmorpholine (vapor pressure 6 mmHg / 20 ° C.), N-methylmorpholine (vapor pressure 17 mmHg / 20 ° C.) A catalyst that does not react with isocyanate and is not incorporated into the polyurethane foam 16. Therefore, although there is a possibility of affecting the corrosion of the headrest stay 15, the volatility is high, so that it volatilizes and does not remain at all after performing the function as a catalyst.

  In the present embodiment, the polyether polyol is a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol. And when it contains 20 mol% or more of a polyethylene oxide unit, a catalyst contains a polyisocyanate and a reactive catalyst and a non-reactive catalyst, and a non-reactive catalyst is comprised with the compound which has volatility. When the polyether polyol is a copolymer of ethylene oxide and propylene oxide and contains 10 to 20 mol% of polyethylene oxide units, the catalyst is a catalyst reactive with polyisocyanate and a non-reactive catalyst. The contained and non-reactive catalyst is composed of a low volatility compound and a high volatility compound.

  Here, the standard for volatility is a boiling point of about 180 ° C. or lower. In addition, in the case of a highly volatile catalyst and a low volatile catalyst, it means that a highly volatile catalyst has a vapor pressure of 3 mmHg / 20 ° C or higher, and a low volatile catalyst has a vapor pressure of less than 3 mmHg / 20 ° C. To do.

  The foaming agent is for foaming polyurethane to form polyurethane foam 16. As the foaming agent, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide, etc. are used in addition to water. Other raw materials for producing polyurethane foam 16 include foam stabilizers such as silicone and surfactant, cell openers such as polyalkylene oxide polyols, flame retardants such as condensed phosphate esters, antioxidants, plasticizers, UV absorbers, Coloring agents and the like can be added.

  When the urethanization reaction between the polyol and the polyisocyanate is performed, a one-shot method or a prepolymer method is employed. The one-shot method is a method in which a polyol and polyisocyanate are directly reacted. The prepolymer method is a method in which a part of a polyol and a polyisocyanate is reacted in advance to obtain a prepolymer having an isocyanate group or a hydroxyl group at a terminal, and the polyol or polyisocyanate is reacted therewith. The one-shot method is a preferable method because the manufacturing process is one step compared to the prepolymer method, and there are few restrictions on the manufacturing conditions, and the manufacturing cost can be reduced.

  When manufacturing polyurethane foam 16 for a headrest, first, a laminated body for producing the skin 12 is formed by sewing into a bag shape, and then inverted from the opening 13 to form a bag-like skin. 12 is produced. Next, the headrest stay 15 is inserted into the inside of the skin 12 and set in the mold.

  And the raw material of the polyurethane foam 16 is inject | poured into the inside of the skin 12 from the opening part 13, a polyol, polyisocyanate, etc. are made to react, and it is foamed and expanded simultaneously. Thereby, the skin 12 and the headrest stay 15 are integrated with the molding layer of the polyurethane foam 16, and the headrest 11 is manufactured.

  In this case, since the polyether polyol contains 20 mol% or more of polyethylene oxide units, in other words, contains many hydroxyl groups, it is considered that the bonding force of the polyurethane foam 16 to the headrest stay 15 is enhanced. It is done. Furthermore, the reactivity with the polyisocyanate is enhanced by the hydroxyl group of the polyether polyol, and the polyurethane foam 16 is prevented from being broken or sinked. Moreover, since a non-reactive catalyst is a volatile compound as a catalyst, it volatilizes after the catalyst performs its function.

  Further, when the content of the polyethylene oxide unit in the polyether polyol is 10 to 20 mol%, a highly volatile compound is contained as a non-reactive catalyst. For this reason, the reactivity of polyether polyol and polyisocyanate can be improved without leaving a catalyst in the polyurethane foam 16.

The effects exhibited by the above embodiment will be described below.
The polyurethane foam 16 for headrest in the embodiment is composed of a polymer in which polyether polyol is obtained by addition polymerization of propylene oxide and ethylene oxide to polyhydric alcohol, and includes 20 mol% or more of polyethylene oxide units. For this reason, it is estimated that the polyurethane foam 16 contains more hydroxyl groups than the normal polyurethane foam 16 having a polyethylene oxide unit of 10 to 20 mol%, and the binding force to the headrest stay 15 is enhanced. Therefore, the adhesiveness of the polyurethane foam 16 to the bent portion of the headrest stay 15, that is, the first bent portion 15 a and the second bent portion 15 b can be improved.

  Moreover, it is estimated that the reactivity with polyisocyanate is improved with the hydroxyl group of polyether polyol. For this reason, tearing and sink marks of the polyurethane foam 16 are suppressed, the headrest stay 15 is prevented from being exposed to the outside air, moisture can be prevented from entering, and oxidation on the surface of the headrest stay 15 can be avoided. Therefore, when the headrest stay 15 is bent after plating, it is possible to suppress corrosion at the bent portion.

  Furthermore, since the non-reactive catalyst is a volatile compound as a catalyst, it is avoided that the catalyst volatilizes after it performs its function and remains in the polyurethane foam 16. For this reason, it is possible to prevent the remaining catalyst from corroding the headrest stay 15.

  -Moreover, when content of the polyethylene oxide unit in polyether polyol is 10-20 mol%, the highly volatile compound is contained as a non-reactive catalyst. For this reason, the reactivity of polyether polyol and polyisocyanate can be improved without leaving a catalyst in the polyurethane foam 16. Therefore, also in this case, the same effect as in the above case where the polyethylene polyol unit is contained in the polyether polyol by 20 mol% or more can be exhibited.

  The headrest obtained by encapsulating the polyurethane foam 16 as described above in the skin can maintain the performance as a headrest for a long period of time without causing corrosion at the bent portion of the headrest stay 15.

Hereinafter, the embodiment will be described more specifically with reference to examples and comparative examples.
Example 1
As a raw material for producing polyurethane foam 16 for headrest, 50 parts by mass of polyether polyol, 50 parts by mass of modified polyether polyol, and a mixture of MDI and modified MDI as polyisocyanate (methylene groups of MDI combined in a straight chain) 70 parts by mass, 2.5 parts by mass of dimethylethanolamine (2-dimethylaminoethanol, DMEA) as a reactive catalyst, 1.0 part by mass of triethylenediamine (TEDA) as a non-reactive catalyst, and water as a blowing agent 5 parts by mass and 1 part by mass of silicone oil were mixed as a foam stabilizer. The polyether polyol is obtained by addition polymerization of propylene oxide to glycerin and addition polymerization of ethylene oxide. The polyether polyol is a polymer having an average molecular weight of 3000 and having 20 mol% of polyethylene oxide units. The modified polyether polyol is obtained by adding 20% by mass of a 1: 1 (molar ratio) mixture of acrylonitrile (AN) and styrene (St) to the polyether polyol.

On the other hand, a mold mold composed of a lower mold and an upper mold was heated to 40 to 65 ° C., and a headrest stay 15 having a chrome-plated steel surface was disposed on the lower mold. Thereafter, the raw material for production was poured into the molding recess of the lower mold. Next, the upper mold was clamped to the lower mold, and the molding was performed by raising the temperature, and the headrest 11 in which the headrest stay 15 was embedded in the polyurethane foam 16 was manufactured. About the obtained headrest 11, the adhesiveness of the headrest stay 15 and the polyurethane foam 16, the tear of the polyurethane foam 16, and the sink of the polyurethane foam 16 were observed, and evaluation was performed according to the following criteria. The results are shown in Table 1.
(Adhesiveness between headrest stay 15 and polyurethane foam 16)
○: Adhesiveness was good. Δ: Adhesiveness was insufficient. X: Adhesiveness was poor.
(Polyurethane foam 16 is torn)
○: No tearing and good. Δ: Some tears were observed. X: Many tears were bad.
(Polish of polyurethane foam 16)
○: No sink marks and good. Δ: Sink was seen in part. X: Many sink marks were bad.
(Example 2)
In Example 1, a polyether polyol having a polyethylene oxide content of 15% by mass was used, and N, N-dimethylamino-ethylmorpholine having a higher volatility than triethylenediamine was used as a non-reactive catalyst in an amount of 0.5% by mass. % Was further added. The rest was manufactured in the same manner as in Example 1.

The headrest 11 was evaluated by observing and evaluating the adhesion between the headrest stay 15 and the polyurethane foam 16, tearing of the polyurethane foam 16, and sink marks of the polyurethane foam 16 in the same manner as in Example 1. Table 1 shows the results. It was.
(Comparative Example 1)
In Example 2, a headrest was produced in the same manner as in Example 1 except that morpholine as a catalyst was not added.

  This headrest was evaluated by observing and evaluating the adhesion between the headrest stay 15 and the polyurethane foam 16, tearing of the polyurethane foam 16, and sink marks of the polyurethane foam 16 in the same manner as in Example 1. The results are shown in Table 1. .

表１に示したように、実施例１及び実施例２ではヘッドレストステー１５とポリウレタンフォーム１６との接着性、ポリウレタンフォーム１６の破れ、及びポリウレタンフォーム１６のひけのいずれも良好な結果であったのに対し、比較例１ではいずれの性能も不充分であった。

As shown in Table 1, in Examples 1 and 2, all of the adhesion between the headrest stay 15 and the polyurethane foam 16, the tearing of the polyurethane foam 16, and the sink of the polyurethane foam 16 were good results. On the other hand, in Comparative Example 1, any performance was insufficient.

In addition, this embodiment can also be changed and embodied as follows.
When the polyethylene polyol unit is contained in an amount of 20 mol% or more as the polyether polyol, highly volatile morpholines can be used as the catalyst.

  When the polyethylene polyol unit is contained in an amount of 20 mol% or more as the polyether polyol, it is also possible to use a combination of a highly volatile catalyst and a low volatile catalyst.

  It is also possible to use an iron alloy or the like that may cause rust as the metal material forming the headrest stay 15 or to use nickel or zinc as a plating material.

Furthermore, the technical idea which can be grasped from the embodiment or another example will be described below.
The non-reactive catalyst and low volatility compound is an amine compound having a vapor pressure of less than 3 mmHg / 20 ° C., and the non-reactive catalyst and highly volatile compound has a vapor pressure of 3 mmHg / 20 ° C. or higher. The polyurethane foam for headrest according to claim 2, which is an amine compound. In such a configuration, it is possible to avoid the remaining of the catalyst after the formation of the polyurethane foam and to suppress the corrosion of the headrest stay.

  The polyurethane foam for headrest according to claim 2, wherein the non-reactive catalyst and the highly volatile compound are morpholines. When configured in this way, it is possible to reliably avoid the catalyst remaining after the formation of the polyurethane foam and suppress corrosion of the headrest stay.

FIG. 2 is a partially cutaway perspective view showing the headrest according to the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Headrest, 12 ... Epidermis, 15 ... Headrest stay, 15a ... The 1st bending part as a bending part, 15b ... The 2nd bending part as a bending part, 16 ... Polyurethane foam.

Claims (3)

A polyurethane foam for forming a headrest by including the headrest stay inserted in a bag-like skin, wherein the headrest stay is bent after the surface of the metal material is plated. The polyurethane foam raw material contains at least a polyether polyol, a polyisocyanate, a catalyst for accelerating their reaction, and a foaming agent so that the portion is located in the headrest and the occurrence of corrosion in the bent portion is prevented. The polyether polyol is a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, and contains 20 mol% or more of polyethylene oxide units, and the catalyst is a catalyst reactive with polyisocyanate and non-polymer. Contains reactive catalyst and non-reactive Headrest for polyurethane foam, wherein the medium is a compound having a volatility. A polyurethane foam for forming a headrest by including the headrest stay inserted in a bag-like skin, wherein the headrest stay is bent after the surface of the metal material is plated. The polyurethane foam raw material contains at least a polyether polyol, a polyisocyanate, a catalyst for accelerating their reaction, and a foaming agent so that the portion is located in the headrest and the occurrence of corrosion in the bent portion is prevented. The polyether polyol is a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, and contains 10 to 20 mol% of a polyethylene oxide unit, and the catalyst is a catalyst reactive with polyisocyanate and Contains non-reactive catalyst and is non-reactive Headrest for polyurethane foam, wherein the sex of the catalyst becomes more compounds with low volatility and high volatility compounds. A headrest characterized in that the polyurethane foam for a headrest according to claim 1 or 2 is contained in a state in which the headrest stay is inserted into a bag-shaped skin.

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