JP2012214778A - Method for producing soft polyurethane foam, and sheet - Google Patents

Abstract

【選択図】なしDisclosed is a method for producing a flexible polyurethane foam, which can suppress the deterioration of the mechanical properties of the foam due to the use of a stored polyol system liquid.
SOLUTION: The polyol has an average number of hydroxyl groups of 2 to 8 and a hydroxyl value of 5 to 45 mgKOH obtained through a step of ring-opening addition polymerization of alkylene oxide in the presence of a double metal cyanide complex catalyst as an initiator. / G polyether polyol (A1) is used. As the foam stabilizer (G), dimethylpolysiloxane represented by the following formula (I) is used.
[Chemical 1]

[Selection figure] None

Description

  The present invention relates to a method for producing a flexible polyurethane foam and a sheet using the flexible polyurethane foam produced by the method.

A flexible polyurethane foam (hereinafter also referred to as a flexible foam) is generally produced by reacting a polyol and a polyisocyanate compound in the presence of a urethanization catalyst and a foaming agent. Specifically, a flexible polyurethane foam is produced by preparing a polyol system liquid containing a polyol, a foaming agent, a foam stabilizer, a catalyst, and the like, and a polyisocyanate compound, and mixing and reacting them.
The flexible polyurethane foam is used as a material for a seat (a seat cushion or a seat backrest), for example. An example of the seat cushion is an automobile seat cushion.
In particular, in an automobile seat cushion, deterioration is likely to occur due to an external force caused by movement of a person during use. Therefore, improvement in mechanical properties such as tear strength, tensile strength, and elongation is desired.

In general, polyether polyol used as a raw material for polyurethane is obtained by ring-opening addition polymerization of alkylene oxide such as propylene oxide to an initiator such as polyhydric alcohol using an alkali catalyst such as sodium hydroxide or potassium hydroxide. Manufactured. In the production method, a monool having an unsaturated bond is produced as a by-product. When a flexible polyurethane foam is produced using a polyol containing the monool and having a high degree of unsaturation, the physical properties of the foam are likely to deteriorate.
On the other hand, in Patent Documents 1 and 2 below, a polyol with low unsaturation is produced by using a double metal cyanide complex catalyst instead of an alkali catalyst, and a flexible polyurethane foam is produced using the polyol. A method is described.

Japanese Patent No. 2616054 Japanese Patent No. 2616055

  According to the knowledge of the present inventors, in a flexible polyurethane foam produced using a polyether polyol obtained by using such a double metal cyanide complex catalyst, by using the stored polyol system liquid, May drop significantly. For example, in a flexible polyurethane foam produced using a polyol system solution stored for 6 days, the cell becomes coarser and mechanical properties (tear strength) are compared with a flexible polyurethane foam produced using a polyol system solution within 24 hours after preparation. It has been found that the tensile strength and elongation) may be significantly reduced. In other words, the longer the storage time after the preparation of the polyol system liquid, the lower the mechanical characteristics of the foam obtained using the system liquid immediately after the preparation may occur (hereinafter this phenomenon). May be referred to as degradation of mechanical properties).

  The present invention has been made in view of the above circumstances, and a method for producing a flexible polyurethane foam capable of suppressing the deterioration of the mechanical properties of the foam due to the use of a stored polyol system liquid, and a flexible polyurethane foam produced by the method. An object is to provide a used sheet.

The present invention is the following [1] to [10].
[1] A step of reacting the polyol (A) with the polyisocyanate compound (B) in the presence of the catalyst (C), the foaming agent (D), and the foam stabilizer (G),
The polyol (A) contains 2 to 100% by mass of the following polyol (A1) in the total amount of the polyol (A),
A method for producing a flexible polyurethane foam, wherein the foam stabilizer (G) is dimethylpolysiloxane represented by the following formula (I).
Polyol (A1): obtained by undergoing ring-opening addition polymerization of alkylene oxide in the presence of a double metal cyanide complex catalyst as an initiator, having an average number of hydroxyl groups of 2 to 8 and a hydroxyl value of 5 to 45 mgKOH / g Of polyether polyols.

[2] The method for producing a flexible polyurethane foam according to [1], wherein the polyol (A1) comprises a polyether polyol obtained by the method for producing the following polyol (A1).
Production method of polyol (A1): In a reaction liquid containing an initiator and a double metal cyanide complex catalyst, a part of the alkylene oxide is 5 to 20 masses per 100 mass parts of the initiator contained in the reaction liquid. The initial activation step (a) to be fed and reacted, and the additional polymerization step (b) to carry out the polymerization reaction by additionally supplying alkylene oxide after the initial activation step (a). The initial temperature of the reaction liquid immediately before the start of supplying a part of the alkylene oxide is 120 to 165 ° C., and the maximum temperature of the reaction liquid in the initial activation step (a) is 15 from the initial temperature. A manufacturing method which is a temperature higher by 50 ° C to 50 ° C.

[3] The method for producing a flexible polyurethane foam according to [1] or [2], wherein the composite metal cyanide complex catalyst has tert-butyl alcohol as an organic ligand.
[4] The method for producing a flexible polyurethane foam according to any one of [1] to [3], wherein 50 to 100% by mass of the polyether polyol (A1) is contained in the total amount of the polyol (A).
[5] The method for producing a flexible polyurethane foam according to any one of [1] to [4], wherein the foaming agent (D) comprises only water.
[6] The method for producing a flexible polyurethane foam according to any one of [1] to [5], wherein the polyol (A) contains the polymer fine particles (H) in a content of more than 0% by mass and 30% by mass or less.
[7] The method for producing a flexible polyurethane foam according to [6], wherein the polyol (A) includes the following polymer-dispersed polyol (A21).
Polymer-dispersed polyol (A21): A polymer-dispersed polyol in which the polymer fine particles (H) are dispersed in a polyol (A2) that is a polyol other than the polyol (A1).
[8] The amount of the foam stabilizer (G) used is 0.001 to 2 parts by mass with respect to the total (100 parts by mass) of the polyol (A) and other high molecular weight active hydrogen compounds. ] The manufacturing method of the flexible polyurethane foam in any one of [7].
[9] A sheet using a flexible polyurethane foam produced by any one of [1] to [8].
[10] The seat according to [9], which is for an automobile.

According to the method for producing a flexible polyurethane foam of the present invention, it is possible to suppress a decrease in foam physical properties due to the use of a stored polyol system liquid.
The obtained flexible polyurethane foam is suitable for a seat, and is particularly suitable as an automobile seat cushion or a furniture cushion.

The “seat” in the present invention is a seat cushion or a seat backrest made of flexible polyurethane foam.
In the present specification, the “polyol system liquid” is a liquid to be reacted with a polyisocyanate compound, and is a liquid containing a compounding agent as required, such as a foaming agent, a foam stabilizer, a catalyst, etc. in addition to a polyol. .
The “reactive mixture” in this specification is a liquid obtained by mixing a polyol system liquid, a polyisocyanate compound, and optionally the remaining components.
In the present specification, the “polyether chain” refers to a structure in which repeating units containing an ether bond are linked in a chain.
The number average molecular weight (Mn), mass average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the polyol in this specification were calculated by gel permeation chromatography using a polystyrene polymer as a reference, so-called polystyrene conversion Molecular weight.
Further, “unsaturation” in the present specification is a value measured in accordance with JIS K1557 (2007 edition).

<Polyol (A)>
The polyol (A) means all of the polyols used for the reaction with the polyisocyanate compound, and may be one kind of polyol, a mixture of two or more kinds of polyols, or polymer particles dispersed in the polyol. Good.
[Polyol (A1)]
The polyol (A) includes a polyol (A1). Polyol (A1) is an average hydroxyl group obtained by subjecting an alkylene oxide to ring-opening addition polymerization to an initiator in the presence of a double metal cyanide complex catalyst (also referred to as DMC catalyst in the present specification). It is a polyether polyol having a number of 2 to 8 and a hydroxyl value of 5 to 45 mgKOH / g. The polyol (A1) has two or more hydroxyl groups in one molecule.

When the polyol (A1) is produced, by using a DMC catalyst as a polymerization catalyst for ring-opening addition polymerization of alkylene oxide, the production of monools having unsaturated bonds as by-products can be suppressed, and the degree of unsaturation can be reduced. Lower. When a flexible foam is produced using a polyol having a low degree of unsaturation, the physical properties of the flexible foam are improved as compared with the case where a polyol having a high degree of unsaturation is used.
The degree of unsaturation of the polyol (A1) is preferably 0.030 meq / g or less, more preferably 0.02 meq / g or less, and particularly preferably 0.015 meq / g or less. When the degree of unsaturation is 0.030 meq / g or less, the mechanical properties of the flexible foam produced using the polyol (A1) are good. Further, when the degree of unsaturation is 0.015 meq / g or less, good compression residual strain and wet heat compression residual strain of the flexible foam produced using the polyol (A1) are easily obtained.

The average number of hydroxyl groups of the polyol (A1) is 2 to 8, preferably 2.5 to 6.5, particularly preferably 2.5 to 4.5. When the average number of hydroxyl groups is not less than the lower limit of the above range, good hardness of the flexible foam is easily obtained. When the amount is not more than the upper limit of the above range, good durability of the flexible foam is easily obtained.
The hydroxyl value of the polyol (A1) is 5-45 mgKOH / g, preferably 5-35 mgKOH / g, particularly preferably 5-25 mgKOH / g. When the hydroxyl value is within the above range, good mechanical properties of the flexible foam are easily obtained.
When the hydroxyl value is 45 mgKOH / g or less, the resonance frequency is easily suppressed low. Moreover, it is preferable that the hydroxyl value is 25 mgKOH / g or less, because the resonance frequency of the obtained flexible foam can be suppressed low, and the hysteresis loss and distortion characteristics are improved.

  When the polyol (A1) is 100% by mass, the total of oxyethylene groups contained in the polyol (A1) is preferably 5 to 30% by mass, more preferably 5 to 20% by mass, and 10 to 20% by mass. % Is particularly preferred. When the total of the oxyethylene groups is at least the lower limit of the above range, sufficient reactivity with the polyisocyanate compound (B) is easily obtained, and when it is at most the upper limit of the above range, the polyisocyanate compound (B) The reactivity of is not too high, and the moldability of the flexible polyurethane foam tends to be good.

The content of the polyol (A1) in the total amount of the polyol (A) is 2 to 100% by mass. When it is at least the lower limit of the above range, the effect of improving the mechanical properties of the flexible foam due to the use of the polyol (A1) can be sufficiently obtained.
According to the knowledge of the present inventors, when the flexible foam is produced using the polyol (A1), the deterioration of the mechanical properties due to the use of the stored polyol system liquid is that the polyol (A1) in the polyol (A) is It is more likely to occur when the ratio is large. Therefore, the present invention is particularly effective when the content of the polyol (A1) in the polyol (A) is 50% by mass or more. The more preferable content of the polyol (A1) in the polyol (A) is 50 to 100% by mass, and 60 to 100% by mass is particularly preferable.

[Double metal cyanide complex catalyst (DMC catalyst)]
A well-known thing can be used for the DMC catalyst in this invention. Typically, it is represented by the following formula (1).
M ¹ _a [M ² _b (CN) _c ] _de (M ³ _f X _g ) h (H ₂ O) i (L) (1)
(In formula (1), M ^{1 to} M ³ are metals, X is a halogen atom, L is an organic ligand, a, b, c, d, e, f, g, h, and i are metals. (The numbers that can vary depending on the valence and the coordination number of the organic ligand are shown.)
In the formula, M ¹ or M ³ represents Zn (II), Fe (II), Fe (III), Co (II), Ni (II), Mo (IV), Mo (VI), Al (III), A metal atom selected from V (V), Sr (II), W (IV), W (VI), Mn (II), Cr (III), Cu (II), Sn (II) and Pb (II) Yes, Zn (II) or Fe (II) is preferred. The Roman numeral in parentheses following the atomic symbol of the metal represents the valence, and so on. M ¹ and M ^{3 in} one molecule may be the same as or different from each other. Preferably they are the same as each other.
M ² is Fe (II), Fe (III), Co (II), Co (III), Cr (II), Cr (III), Mn (II), Mn (III), Ni (II), V A metal atom selected from (IV) and V (V), preferably Co (III) or Fe (III).
X is a halogen atom.

L represents an organic ligand. As the organic ligand, alcohol, ether, ketone, ester, amine, amide and the like can be used, and alcohol is preferable. Preferred organic ligands are water-soluble, and specific examples include tert-butyl alcohol, n-butyl alcohol, iso-butyl alcohol, tert-pentyl alcohol, iso-pentyl alcohol, N, N-dimethylacetamide, Selected from the group consisting of ethylene glycol dimethyl ether (also referred to as glyme), diethylene glycol dimethyl ether (also referred to as diglyme), triethylene glycol dimethyl ether (also referred to as triglyme), ethylene glycol mono-tert-butyl ether, iso-propyl alcohol, and dioxane. 1 type or 2 or more types of compounds are mentioned. Dioxane may be 1,4-dioxane or 1,3-dioxane, and 1,4-dioxane is preferred.
More preferred organic ligands are tert-butyl alcohol, tert-pentyl alcohol, ethylene glycol mono-tert-butyl ether, or a combination of tert-butyl alcohol and ethylene glycol mono-tert-butyl ether. Higher polymerization activity is obtained, which is preferable in terms of reducing the molecular weight distribution of the polyol (A1).

As the DMC catalyst in the present invention, in terms of catalytic activity, those in which the organic ligand L is tert-butyl alcohol or ethylene glycol mono-tert-butyl ether are preferred, and tert-butyl alcohol is particularly preferred.
In Formula (1), M ¹ and M ³ are the same as each other, Zn (II) or Fe (II), M ² is Co (III) or Fe (III), X is halogen, L Is preferably tert-butyl alcohol or ethylene glycol mono-tert-butyl ether, M ¹ and M ³ are Zn (II), M ² is Co (III), X is chlorine (Cl), and L is tert-butyl. Particularly preferred are alcohols.

  The manufacturing method of a DMC catalyst is not specifically limited, A well-known method can be used suitably. For example, (i) an organic ligand is coordinated to a reaction product obtained by reacting a metal halide salt with a cyanometalate acid and / or an alkali metal cyanometalate in an aqueous solution, and then generated. A method in which the solid component is separated and the separated solid component is further washed with an organic ligand aqueous solution, or (ii) a metal halide salt, a cyanometallate and / or an alkali metal cyano in the organic ligand aqueous solution The reaction product (solid component) obtained by reacting with metallate is separated, and the cake (solid component) obtained by the method of washing the separated solid component with an organic ligand aqueous solution is filtered and separated. Furthermore, the method of drying is mentioned.

The metal constituting the cyano metalate of the alkali metal cyano metalate corresponds to M ² in the above formula (1).
Examples of the cyanometalate or alkali metal cyanometalate used as the raw material for producing the DMC catalyst of the present invention include H ₃ [Co (CN) ₆ ], Na ₃ [Co (CN) ₆ ], or K ₃ [Co ( CN) ₆ ] is preferable, and Na ₃ [Co (CN) ₆ ] or K ₃ [Co (CN) ₆ ] is particularly preferable.

Before the cake is filtered and separated, the polyether polyol is mixed with the liquid in which the solid component is dispersed in the organic ligand aqueous solution, and water and excess organic ligand are distilled off from the obtained mixed liquid. Thus, a slurry-like DMC catalyst mixture in which the DMC catalyst is dispersed in the polyether polyol (hereinafter, also referred to as “slurry DMC catalyst”) can be prepared.
The polyether polyol used to prepare the slurry-like DMC catalyst is an anionic polymerization catalyst or a cationic polymerization catalyst, and an alkylene oxide is subjected to ring-opening addition polymerization to one or more initiators selected from the group consisting of polyhydric alcohols. Can be manufactured. The polyether polyol preferably has 2 to 8 hydroxyl groups and a number average molecular weight (Mn) of 300 to 5,000. It is preferable from the viewpoint that the polymerization activity of the DMC catalyst is high and the viscosity of the slurry-like DMC catalyst does not increase and is easy to handle.

The amount of the DMC catalyst used in the method for producing the polyol (A1) is set to be more than an amount necessary for obtaining the target molecular weight of the polyol (A1).
Moreover, it is preferable to make the usage-amount of a DMC catalyst as small as possible, and to reduce the DMC catalyst which remains in the obtained polyol (A1), and the metal compound derived from a DMC catalyst. Thereby, the influence of the residual DMC catalyst on the reaction rate of the polyol (A1) and the polyisocyanate compound and the physical properties of the flexible foam produced using the polyol (A1) as a raw material can be reduced.

Usually, after ring-opening addition polymerization of alkylene oxide with an initiator, an operation of removing the DMC catalyst from the obtained polyol (A1) is performed. However, if the amount of the DMC catalyst remaining in the polyol (A1) is small and does not adversely affect the subsequent reaction with the polyisocyanate compound and the properties of the final product, the polyol (A1) is used without removing the DMC catalyst. Therefore, the production efficiency of the polyol (A1) can be increased.
Specifically, the total amount of metals (for example, Zn and Co) derived from the DMC catalyst contained in the polyol (A1) at the end of the polymerization reaction is preferably 1 to 30 ppm, and preferably 10 ppm or less. Particularly preferred. When the total amount of metals derived from the DMC catalyst is 30 ppm or less, removal of the residual catalyst from the obtained polyol (A1) tends to be unnecessary.

  Moreover, the removal process of the DMC catalyst from the obtained polyol (A1) and / or the deactivation process of a DMC catalyst can also be performed as needed. Examples of the method include an adsorption method using an adsorbent selected from synthetic silicates (magnesium silicate, aluminum silicate, etc.), ion exchange resins and activated clay, amines, alkali metal hydroxides, organic acids, or minerals. An acid neutralization method, a method using a neutralization method and an adsorption method in combination, or the like can be used.

[Initiator]
The initiator used for the production of the polyol (A1) is a compound having two or more hydroxyl groups in one molecule. The preferable number of hydroxyl groups of the initiator is 2 to 12, more preferably 2 to 8, and particularly preferably 2 to 6. When an initiator having 12 or less hydroxyl groups is used, the molecular weight distribution of the resulting polyol (A1) tends to be small. Only 1 type of initiator may be used or it may use 2 or more types together. The average number of hydroxyl groups of the initiator is 2 to 8, preferably 2.5 to 6.5, particularly preferably 2.5 to 4.5.
Specific examples of the initiator include water; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-cyclohexanediol, 1,3-butanediol, 1,4-butanediol, Dihydric alcohols such as 1,6-hexanediol and 1,4-cyclohexanediol; trihydric or higher polyhydric alcohols such as glycerin, diglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol; Sugars such as glucose, sorbitol, dextrose, fructose, sucrose, methyl glucoside or derivatives thereof; phenols such as bisphenol A, bisphenol F, bisphenol S, novolac, resole, resorcin, etc. It is.

  As the initiator, a compound selected from the group consisting of polyether polyol and polyoxytetramethylene glycol obtained by polymerizing an alkylene oxide to these compounds by a known method can also be used as the initiator. The compound preferably has a number average molecular weight (Mn) of 300 to 20,000 and 2 to 12 hydroxyl groups per molecule. The hydroxyl value is preferably 187 mgKOH / g or less.

The number average molecular weight (Mn) of the initiator is preferably 18 to 20,000, more preferably 300 to 10,000, and particularly preferably 600 to 5,000. When an initiator having a number average molecular weight (Mn) of 300 or more is used, the time until the ring-opening addition polymerization reaction starts in the presence of a DMC catalyst can be shortened. When the number average molecular weight (Mn) is 20,000 or less, the viscosity of the initiator is not too high, and the ring-opening addition polymerization reaction tends to be uniform.
In addition, when it is comprised only from the molecule | numerator of the same molecular weight, such as a low molecular alcohol as an initiator, let the molecular weight calculated | required from chemical formula be the number average molecular weight (Mn) of an initiator.
The hydroxyl value of the initiator is preferably 6,300 mgKOH / g or less, more preferably 300 mgKOH / g or less, and particularly preferably 187 mgKOH / g or less.

[Alkylene oxide]
By reacting the alkylene oxide with the active hydrogen atom of the initiator, the alkylene oxide undergoes ring-opening addition to produce a polyol having an oxyalkylene group. Hydroxyalkyl group is formed by ring-opening addition of one molecule of alkylene oxide to active hydrogen atom, and alkylene oxide is ring-opening addition to the hydroxyl group, and this reaction is repeated to form a chain of oxyalkylene groups. To do. When the alkylene oxide is ethylene oxide, oxyethylene groups are chained. When the alkylene oxide is propylene oxide, oxypropylene groups are chained.

When the polyol (A1) is produced, the alkylene oxide to be subjected to ring-opening addition polymerization to the initiator is preferably an alkylene oxide having 2 to 20 carbon atoms. Specific examples include ethylene oxide (hereinafter also referred to as EO), propylene oxide (hereinafter also referred to as PO), 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, oxetane, cyclopentane oxide, and cyclohexene. Examples thereof include oxides and α-olefin oxides having 5 to 20 carbon atoms. One type of alkylene oxide may be used, or two or more types may be used.
Of these, ethylene oxide, propylene oxide, 1,2-butylene oxide and 2,3-butylene oxide are preferred, and ethylene oxide and propylene oxide are particularly preferred. In particular, it is preferable to use propylene oxide alone or both propylene oxide and ethylene oxide, and it is particularly preferable to use propylene oxide alone. By using propylene oxide alone, wet heat compression set of the obtained flexible urethane foam becomes good. When two or more alkylene oxides are used, the ring-opening addition polymerization of alkylene oxide to the initiator may be random polymerization, block polymerization, or combination of random polymerization and block polymerization.

[Method for producing polyol (A1)]
In a preferred method for producing the polyol (A1), a part of the alkylene oxide (hereinafter sometimes referred to as an initial activation monomer) is contained in the reaction liquid in a reaction liquid containing an initiator and a DMC catalyst. After the initial activation step (a) in which 5 to 20 parts by mass are supplied and reacted with respect to 100 parts by mass of the initiator, and after the initial activation step (a), an alkylene oxide is additionally supplied and polymerization is performed. And an additional polymerization step (b) to be reacted.
In the addition polymerization step of ring-opening addition polymerization of the alkylene oxide, a solvent (addition polymerization solvent) that does not adversely affect the ring-opening addition polymerization reaction may be used as appropriate. Examples of such an addition polymerization solvent include hexane, cyclohexane, benzene, and ethyl methyl ketone. When the addition polymerization solvent is not used, the step of removing the solvent from the product is unnecessary, and the productivity can be increased. In addition, the catalytic activity of the DMC catalyst may be reduced due to the influence of moisture and antioxidants contained in the addition polymerization solvent, and such inconvenience can be prevented by not using the addition polymerization solvent.
This method is preferably carried out batchwise. Specifically, it can be carried out as follows.

Initial activation step (a)
First, the total amount of initiator and the total amount of DMC catalyst are placed in a pressure-resistant reaction vessel equipped with stirring means and temperature control means, and mixed to prepare a reaction solution. Usually, the initiator is a viscous liquid, and the DMC catalyst is in the form of particles or a slurry containing the particles. The reaction solution may contain an addition polymerization solvent as required. The reaction solution may also contain components added as necessary in the production process of the DMC catalyst.
“Mixing” of the initiator and the DMC catalyst means a state in which both are uniformly mixed as a whole. In the initial activation step (a) (hereinafter also referred to as step (a)), both of them are like this. It is necessary to be in a “mixed” state.
The mixing means in the step (a) is not particularly limited as long as it can sufficiently mix the DMC catalyst and the initiator (including components added as necessary). Usually, a stirring means is used as the mixing means.

Next, the inside of the pressure-resistant reaction vessel is preferably purged with nitrogen. Thereby, oxygen in the reaction solution is removed. The amount of oxygen in the reaction solution is preferably 1% by mass or less based on the amount of nitrogen.
Exhaust in the pressure-resistant reaction vessel is preferably performed when necessary in the process, such as when the initiator has too much water.

Next, the reaction solution is heated while being stirred, and then heated, and then the initial activation monomer is supplied and reacted in a state where the temperature of the reaction solution is at a predetermined initial temperature (initial activation). The initial temperature in this specification refers to the temperature of the reaction solution immediately before the start of the supply of the initial activation monomer.
The initial temperature of the reaction solution is 120 to 165 ° C. Preferably it is 125-150 degreeC, and 130-140 degreeC is especially preferable. When the initial temperature is not less than the lower limit of the above range, the catalytic activity is remarkably improved, and when it is not more than the upper limit of the above range, there is no fear that the components contained in the reaction solution are thermally decomposed.

  Specifically, it is preferable to raise the temperature to the initial temperature while stirring the reaction solution, and to start supplying the alkylene oxide in a state where the temperature of the reaction solution is maintained. For example, when the reaction solution reaches a predetermined initial temperature, the heating is stopped, and the supply of alkylene oxide is started before the temperature of the reaction solution starts to decrease. The time from when the heating is stopped to when the supply of alkylene oxide starts is not particularly limited, but is preferably within 1 hour from the viewpoint of efficiency.

The monomer for initial activation is a part of alkylene oxide that undergoes ring-opening addition polymerization to an initiator in the production of the polyol (A1).
The supply amount of the initial activation monomer is preferably 5 to 20 parts by mass, more preferably 8 to 15 parts by mass, and particularly preferably 10 to 12 parts by mass with respect to 100 parts by mass of the initiator contained in the reaction solution. If it is at least the lower limit of the above range, initial activation tends to occur, and if it is at most the upper limit, runaway reaction is likely to be prevented.

The initial activation monomer is supplied in a state where the pressure-resistant reaction vessel is sealed. When the initial activation monomer is supplied to the reaction solution, immediately after the unreacted initial activation monomer is vaporized, the internal pressure of the pressure resistant reactor rises. Next, when the DMC catalyst is initially activated, a reaction between the initial activation monomer and the initiator occurs, and the internal pressure of the pressure-resistant reaction vessel starts to decrease, and at the same time, the temperature of the reaction liquid rises due to reaction heat. When the total amount of the supplied initial activation monomer has been reacted, the internal pressure of the pressure-resistant reaction vessel is reduced to the same level as before the supply, and the temperature of the reaction solution is not increased by reaction heat.
In this specification, the initial activation step refers to a step from the start of supplying the initial activation monomer to the completion of the reaction of the initial activation monomer. The completion of the reaction of the initial activation monomer can be confirmed by a decrease in the internal pressure of the pressure resistant reactor. That is, the end of the initial activation process means a time when the internal pressure of the pressure resistant reactor has decreased to the same level as before the supply of the initial activation monomer.

In the step (a), the maximum temperature of the reaction solution is set to be 15 ° C. to 50 ° C. higher than the initial temperature of the reaction solution. The maximum temperature is more preferably 20 ° C or higher than the initial temperature, and particularly preferably 25 ° C or higher. Since the amount of heat generated by the reaction between the initial activation monomer and the initiator is large, the temperature of the reaction solution usually rises to a maximum temperature of 15 ° C. higher than the initial temperature without heating, and then cooled. Even without it, the temperature gradually decreases. The greater the amount of initial activation monomer, the greater the temperature rise of the reaction solution due to reaction heat. The reaction solution may be cooled as necessary, for example, when the temperature is too high. After reaching the maximum temperature, it is preferable to cool the reaction solution in order to shorten the time for the temperature to decrease.
Cooling can be performed, for example, by a method of exchanging heat by providing a cooling pipe through which a refrigerant flows in the reaction solution. The temperature of the reaction liquid can be controlled by the temperature of the refrigerant, the circulation speed of the refrigerant, and the circulation timing of the refrigerant.

When the difference between the maximum temperature and the initial temperature of the reaction solution is not less than the lower limit of the above range, a polyol (A1) having a small molecular weight distribution is easily obtained. If the difference between the maximum temperature of the reaction solution and the initial temperature exceeds 50 ° C., it is not preferable because of the pressure-resistant structure of the reaction vessel.
The maximum temperature value is preferably in the range of 135 to 180 ° C, more preferably in the range of 145 to 180 ° C, and particularly preferably in the range of 150 to 180 ° C.
The temperature of the reaction liquid in the step (a) is such that the reaction temperature of the initial activation monomer is increased after the temperature of the reaction liquid rises and reaches the maximum temperature in accordance with the reaction between the initial activation monomer and the initiator. Until completion, it is preferably kept in a temperature range above the initial temperature, and particularly preferably kept in a temperature range higher than the initial temperature by 15 ° C. or more.

Additional polymerization step (b)
After the initial activation step (a), the remainder of the alkylene oxide is additionally supplied, the temperature of the reaction solution is adjusted to a predetermined polymerization temperature, and the polymerization reaction is performed with stirring to obtain the target polyol (A1).
The additional polymerization step (b) (hereinafter also referred to as step (b)) may be a method in which step (a) is followed by one-stage ring-opening addition polymerization in the presence of a DMC catalyst. A method of performing two-stage ring-opening addition polymerization may be used.
When the step (b) is performed in one step, after the step (a), all of the remaining alkylene oxide is additionally supplied and subjected to ring-opening addition polymerization in the presence of a DMC catalyst to obtain the target polyol (A1).
When step (b) is performed in two steps, after step (a), a part of the remaining ethylene oxide is additionally supplied and subjected to ring-opening addition polymerization in the presence of a DMC catalyst to obtain an intermediate polyol ( Hereinafter, it is also referred to as step (b1)), and then, in the presence of a polymerization catalyst other than the DMC catalyst, the remaining alkylene oxide is additionally supplied and subjected to ring-opening addition polymerization to obtain the target polyol (A1) ( Hereinafter, the step (b2) is also performed.

In the step (b), a block chain is formed if one additional alkylene oxide is supplied, and a random copolymer chain is formed if it is a mixture of two or more alkylene oxides.
In step (b), a heat-resistant reaction vessel equipped with stirring means and temperature control means is used as the reaction vessel. As the heat-resistant reaction vessel, a pressure-resistant autoclave vessel is preferably used. However, when the boiling point of the additionally supplied alkylene oxide is high, it may not be pressure-resistant. The material is not particularly limited. As the reaction vessel, the vessel used in the above step (a) can be used as it is.
The ring-opening addition polymerization reaction in the step (b) is preferably a batch method, but the reaction solution (mixture containing the DMC catalyst and the initiator) and the alkylene oxide supplied after the step (a) is finished, and the product It is also possible to carry out the continuous method in which the polyol (A1) is simultaneously extracted. In particular, when the average molecular weight per hydroxyl group of the initiator is 300 or less, the continuous method is preferable.

When the alkylene oxide is additionally supplied, immediately after the unreacted alkylene oxide is vaporized, the internal pressure of the reaction vessel increases. Next, a reaction between the alkylene oxide and the initiator occurs, and the internal pressure of the reaction vessel begins to decrease, and at the same time, reaction heat is generated. When the total amount of the additionally supplied alkylene oxide has been reacted, the internal pressure of the reaction vessel is reduced to the same level as before the additional supply.
The completion of the reaction of the additionally supplied alkylene oxide can be confirmed by a decrease in the internal pressure of the reaction vessel.

The temperature (polymerization temperature) of the reaction liquid when the additionally supplied alkylene oxide is reacted is preferably in the range of 125 to 180 ° C, particularly preferably in the range of 125 to 160 ° C. When the polymerization temperature is at least the lower limit of the above range, a good reaction rate can be easily obtained, and the remaining amount of unreacted product in the final product can be lowered. When the amount is below the upper limit of the above range, the high activity of the DMC catalyst is maintained well, and the molecular weight distribution tends to be small.
After completion of the reaction of the additionally supplied alkylene oxide, it is preferable to cool the reaction solution and purify the reaction product.

  In the step (b2) when the step (b) is performed in two steps, a ring-opening addition polymerization reaction of alkylene oxide is performed using a polymerization catalyst other than the DMC catalyst. As the polymerization catalyst, alkali metal hydroxides such as sodium hydroxide (NaOH), potassium hydroxide (KOH), cesium hydroxide (CsOH) are preferably used. As the alkylene oxide, those listed above can be used.

Specifically, it is preferable to carry out ring-opening addition polymerization by adding an alkali metal hydroxide as a polymerization catalyst to the reaction liquid after step (b1) and further adding EO. Thus, a polyether having a straight cap structure in which a block chain composed of an oxyethylene group (also referred to as a terminal oxyethylene group in the present specification) is added to the end of the polyol obtained in steps (a) and (b1). A polyol (hereinafter also referred to as “polyol (A1-EO)”) is obtained.
The amount of the polymerization catalyst (alkali metal hydroxide) used in the step (b2) is preferably as small as possible. The amount used is preferably, for example, about 3,000 ppm with respect to the finished amount of the polyol (A1-EO) to be obtained.
30-160 degreeC is preferable, as for the ring-opening addition polymerization temperature of EO in a process (b2), 50-150 degreeC is preferable, and 60-150 degreeC is especially preferable. The ring-opening addition polymerization reaction in the step (b2) is preferably performed with stirring. Moreover, you may use the said addition polymerization solvent.
The supply amount of EO in the step (b2) is the proportion of the block chain composed of terminal oxyethylene groups when the polyether polyol (A1-EO) finally obtained is 100% by mass (containing terminal oxyethylene groups) The amount is preferably in the range of 5 to 30% by mass, particularly preferably 10 to 20% by mass. When the content of the terminal oxyethylene group is not less than the lower limit of the above range, sufficient reactivity with the polyisocyanate compound (B) is easily obtained. It is easy to control reaction with a polyisocyanate compound (B) as it is below the upper limit of the said range.

  In addition, you may perform the removal process of a DMC catalyst, and the deactivation process of a DMC catalyst as needed from the polyol (A1) obtained by this method. As the method, for example, an adsorption method using an adsorbent selected from synthetic silicate (magnesium silicate, aluminum silicate, etc.), ion exchange resin, activated clay, etc., amine, alkali metal hydroxide, phosphoric acid, A neutralization method using an organic acid such as lactic acid, succinic acid, adipic acid, or acetic acid or a salt thereof, or an inorganic acid such as sulfuric acid, nitric acid, or hydrochloric acid, a method that uses a neutralization method and an adsorption method in combination, or the like can be used.

To the polyol (A1) thus obtained, a stabilizer may be added as necessary in order to prevent deterioration during long-term storage.
Examples of the stabilizer include hindered phenol antioxidants such as BHT (dibutylhydroxytoluene).

When the polyol (A1) is produced, the molecular weight distribution (Mw / Mn) of the obtained polyol (A1) can be further reduced by performing the step (a) at the specific temperature. This lowers the viscosity of the polyol (A1) and improves the handleability.
In particular, the high molecular weight polyol (A1) having a small hydroxyl value has a larger number average molecular weight (Mn) of 100,000 or more as the molecular weight distribution is wider, and the viscosity of the polyol becomes significantly higher. The effect of lowering viscosity by reducing the molecular weight distribution is great.

  The reason why such a polyol (A1) having a small molecular weight distribution can be obtained is not clear, but is presumed to be as follows. The DMC catalyst can be obtained only as an agglomerate having no catalytic activity when the catalyst is produced. Therefore, in the ring-opening addition polymerization using the DMC catalyst, by performing the initial activation step (a), the aggregate is crushed, the surface area of the DMC catalyst is increased, and the catalytic activity is exhibited. At this time, by using the initiator, the DMC catalyst, and a part of the alkylene oxide, the initial activation step (a) is performed under a condition that reaches a maximum temperature higher than the initial temperature, so that the DMC catalyst aggregate is more efficiently crushed. And the catalytic activity is further improved. And, until the ring-opening addition polymerization reaction of the alkylene oxide additionally supplied in the step (b) is completed, the high activity of the DMC catalyst is maintained well, and many polymers having a uniform molecular weight are produced. Conceivable.

  Of the hydroxyl groups present in the polyol (A1), the primary ratio (unit: mol%) represented by the ratio of primary hydroxyl groups is preferably 75 mol% or more, and more preferably 80 mol% or more. When it is 75 mol% or more, the reactivity with the polyisocyanate compound (B) is sufficient.

[Other polyol (A2)]
The polyol (A) may contain other polyols (A2) that do not fall under the polyol (A1) as long as the effects of the present invention are not impaired.
Examples of the other polyol (A2) include other polyether polyols, polyester polyols, and polycarbonate polyols that are not included in the category of the polyol (A1). However, what is contained in either the below-mentioned crosslinking agent (E) or foam breaker (F) shall not be contained in a polyol (A2).
These can be known ones. The polyol (A2) is, for example, a polyether polyol obtained by ring-opening addition polymerization of alkylene oxide as an initiator using an alkali metal hydroxide as a polymerization catalyst. The polyol (A2) may be used alone or in combination of two or more.

2-8 are preferable and, as for the average hydroxyl number of a polyol (A2), 2-6 are especially preferable. When the average number of hydroxyl groups is not less than the lower limit of the above range, good durability and riding comfort of the flexible foam can be easily obtained. When the amount is not more than the upper limit of the above range, good mechanical properties of the flexible foam can be easily obtained.
The hydroxyl value of the polyol (A2) is preferably 20 to 160 mgKOH / g, particularly preferably 22 to 60 mgKOH / g. When the hydroxyl value is not less than the lower limit of the above range, the viscosity becomes low, and good workability is easily obtained. When the amount is not more than the upper limit of the above range, good mechanical properties of the flexible foam can be easily obtained.
The number average molecular weight (Mn) of the polyol (A2) is preferably 700 to 22,000, more preferably 1,500 to 20,000, and particularly preferably 2,000 to 15,000.
The content of the polyol (A2) in the total amount of the polyol (A) is 98% by mass or less, preferably 90% by mass or less, and particularly preferably 80% by mass or less.

[Polymer-dispersed polyol]
The polyol (A) may contain polymer particles (H). By containing the polymer particles (H), the hardness, air permeability and other physical properties of the flexible foam can be improved.
For example, the polyol (A1) may be used as a base polyol, and a polymer-dispersed polyol in which polymer particles (H) are dispersed may be contained in the polyol (A), or another polyol (A2) may be used as a bale polyol. The polymer dispersed polyol (A21) in which the polymer particles (H) are dispersed may be contained in the polyol (A), or both of them may be used. It is preferable to use a polymer-dispersed polyol (A21) in which polymer particles (H) are dispersed in another polyol (A2), and the other polyol (A2) is an initiator in the presence of an alkali metal hydroxide catalyst. Particularly preferred is a polyether polyol obtained by ring-opening addition polymerization of alkylene oxide.
The polymer particles (H) are preferably particles obtained by polymerizing the vinyl monomer (M), and may be particles obtained by polymerizing the condensation monomer (N). In view of moldability and foam physical properties, particles obtained by polymerizing the vinyl monomer (M) are preferred.

[Vinyl monomer (M)]
Examples of the vinyl monomer (M) include acrylonitrile, styrene, methacrylic acid ester and acrylic acid ester. A vinyl-type monomer may be used individually by 1 type, and may use 2 or more types together. As the vinyl monomer, a combination of acrylonitrile and styrene is preferable.
[Condensation monomer (N)]
Examples of the condensation polymer (N) include polyester, polyurea, polyurethane, and melamine.

The polymer-dispersed polyol is obtained by polymerizing monomers in a base polyol to form polymer particles.
The hydroxyl value of the polymer-dispersed polyol is a value measured according to JIS K1557-1: 2007.
The hydroxyl value of the whole polymer-dispersed polyol is generally lower than the hydroxyl value of the base polyol.

When the polymer-dispersed polyol (A21) in which the polymer particles (H) are dispersed in another polyol (A2) is used, the hydroxyl value of the polymer-dispersed polyol (A21) is preferably 15 to 50 mgKOH / g, and 17 to 40 mgKOH / G is particularly preferred.
When the polymer-dispersed polyol (A21) is used, the content (including polymer particles) of the polymer-dispersed polyol (A21) in the polyol (A) is preferably more than 0 to 60% by mass, more preferably 10 to 60% by mass. 10 to 55% by mass is preferable.
Moreover, 30 mass% or less is preferable and, as for content of the polymer particle (H) in the whole polyol (A), 25 mass% or less is especially preferable. When the content of the polymer particles (H) is not more than the upper limit of the above range, the viscosity of the polyol (A) becomes appropriate, and good workability is easily obtained. Although the minimum of content of a polymer particle (H) is not specifically limited, 1 mass% or more is preferable and 3 mass% is especially preferable at the point from which the effect by containing a polymer particle is fully acquired easily.

<Other high molecular weight active hydrogen compounds>
As the compound to be reacted with the polyisocyanate compound (B), a compound having active hydrogen other than the polyol (A) may be used in combination with the polyol (A). However, what is contained in any of the below-mentioned crosslinking agent (E) and foam breaker (F) shall not be contained in the said other high molecular weight active hydrogen compound.
Other high molecular weight active hydrogen compounds include high molecular weight polyamines having two or more primary amino groups or secondary amino groups; one or more primary amino groups or secondary amino groups and one or more hydroxyl groups High molecular weight compounds; piperazine-based polyols and the like.

  The high molecular weight polyamine or the high molecular weight compound includes a compound obtained by converting a part or all of hydroxyl groups of a polyether polyol into an amino group; an isocyanate at the terminal obtained by reacting a polyether polyol and an excess equivalent amount of a polyisocyanate compound. The compound which hydrolyzed the isocyanate group of the prepolymer which has a group, and was converted into the amino group is mentioned.

Piperazine-based polyols are polyether polyols obtained by ring-opening addition polymerization of alkylene oxides with piperazines.
Piperazine means piperazine or a substituted piperazine in which a hydrogen atom in piperazine is substituted with an organic group such as an alkyl group or an aminoalkyl group.
Piperazines have at least two active hydrogens.
In the piperazine-based polyol, two nitrogen atoms constituting the piperazine ring are tertiary amines.

As piperazines, piperazine, alkylpiperazines in which a hydrogen atom bonded to a carbon atom constituting a ring is substituted with a lower alkyl group (2-methylpiperazine, 2-ethylpiperazine, 2-butylpiperazine, 2-hexylpiperazine, 2 , 5-, 2,6-, 2,3- or 2,2-dimethylpiperazine, 2,3,5,6- or 2,2,5,5-tetramethylpiperazine, etc.), nitrogen constituting the ring Examples include N-aminoalkylpiperazines (N- (2-aminoethyl) piperazine etc.) in which a hydrogen atom bonded to an atom is substituted with an aminoalkyl group. Substituted piperazines are preferred, and hydrogen is substituted with an aminoalkyl group or the like. Particularly preferred are substituted piperazines having three or more nitrogen atoms in the molecule, such as piperazine.
Moreover, as substituted piperazine, N-substituted piperazine is preferable, N-aminoalkyl piperazine is more preferable, and N- (aminoethyl) piperazine is especially preferable.

  The alkylene oxide that undergoes ring-opening addition polymerization to piperazine is preferably an alkylene oxide having 2 or more carbon atoms, and examples thereof include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and styrene oxide.

The molecular weight per functional group of other high molecular weight active hydrogen compounds is preferably 400 or more, particularly preferably 800 or more. The upper limit of the molecular weight per functional group is preferably 5,000 or less.
The average number of functional groups of other high molecular weight active hydrogen compounds is preferably 2-8.

  The proportion of the other high molecular weight active hydrogen compound is preferably 20 parts by mass or less, particularly preferably 0 part by mass, of the total (100 parts by mass) of the polyol (A) and the other high molecular weight active hydrogen compound. If the ratio of another high molecular weight active hydrogen compound is 20 mass parts or less, the reactivity with a polyisocyanate compound (B) will not become large too much, and the moldability of a flexible foam will become favorable.

<Polyisocyanate compound (B)>
Examples of the polyisocyanate compound (B) include aromatic polyisocyanate compounds having two or more isocyanate groups, mixtures of two or more thereof, and modified polyisocyanates obtained by modifying them. Specifically, at least one selected from the group consisting of tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate (commonly known as polymeric MDI or crude MDI) and modified products thereof is preferable. Examples of the modified body include a prepolymer modified body, a nurate modified body, a urea modified body, and a carbodiimide modified body. The polyisocyanate compound (B) may be used alone or in combination of two or more.
Among these, it is preferable that TDI or MDI is included, and it is preferable that at least TDI is included from the viewpoint that the obtained flexible foam can be reduced in weight, and a mixture of TDI and MDI is preferable. The mixing ratio (mass ratio) of TDI and MDI is, for example, 100/0 to 0/100, preferably 100/0 to 10/90, and particularly preferably 90/10 to 50/50.

  The polyisocyanate compound (B) may be a prepolymer. Examples of the prepolymer include TDI, MDI or crude MDI (also referred to as polymeric MDI), a polyol derived from natural fats and oils, a polyether polyol obtained by ring-opening addition polymerization of an alkylene oxide to a polyol derived from natural fats and oils, or a petroleum-based polyether polyol. Of the prepolymer.

  The amount of the polyisocyanate compound (B) used is preferably 70 to 125 in terms of isocyanate index, more preferably 80 to 120, and particularly preferably 85 to 120. The isocyanate index is a numerical value represented by 100 times the number of isocyanate groups with respect to the total of all active hydrogens such as polyol (A), other high molecular weight active hydrogen compounds, crosslinking agent (E), and water.

<Catalyst (C)>
The catalyst (C) is a catalyst that accelerates the urethanization reaction.
Examples of the catalyst (C) include amine compounds, organometallic compounds, reactive amine compounds, and carboxylic acid metal salts. A catalyst (C) may be used individually by 1 type, and may combine 2 or more types.

Examples of the amine compound include a dipropylene glycol solution of triethylenediamine, a dipropylene glycol solution of bis- (2-dimethylaminoethyl) ether, aliphatic amines such as morpholines and piperazines, and alicyclic amines.
In order to suppress the initial thickening in the urethanization reaction and improve the moldability, it is preferable to use piperazines.
The reactive amine compound is a compound that is hydroxylated or aminated so that a part of the structure of the amine compound reacts with an isocyanate group.
Examples of the reactive amine compound include dimethylethanolamine, trimethylaminoethylethanolamine, and dimethylaminoethoxyethoxyethanol.
The amount of the amine compound catalyst and the reactive amine compound catalyst is preferably 2 parts by mass or less with respect to the total (100 parts by mass) of the polyol (A) and other high molecular weight active hydrogen compounds, and is 0.05 to 1.5. Part by mass is particularly preferred.

Examples of organometallic compounds include organotin compounds, organobismuth compounds, organolead compounds, and organozinc compounds. Specific examples include di-n-butyltin oxide, di-n-butyltin dilaurate, di-n-butyltin, di-n-butyltin diacetate, di-n-octyltin oxide, di-n-octyltin dilaurate, mono Examples thereof include butyltin trichloride, di-n-butyltin dialkyl mercaptan, and di-n-octyltin dialkyl mercaptan.
The amount of the organometallic compound is preferably 2 parts by mass or less, particularly preferably 0.005 to 1.5 parts by mass with respect to the total (100 parts by mass) of the polyol (A) and other high molecular weight active hydrogen compounds.

<Foaming agent (D)>
As the foaming agent (D), at least one selected from water and an inert gas is preferable. Only water is preferable from the viewpoint of easy handling and reduction of environmental burden.
Examples of the inert gas include air, nitrogen gas, and liquefied carbon dioxide gas.
What is necessary is just to adjust the quantity of a foaming agent (D) suitably according to requests | requirements, such as a foaming ratio.

According to the knowledge of the present inventors, when the flexible polyurethane foam is produced using the polyol (A1), the deterioration of the mechanical properties due to the use of the stored polyol system liquid occurs when water is used as the foaming agent. It's easy to do. Therefore, the present invention is more effective when the foaming agent contains water, and the effect is particularly great when the foaming agent consists only of water.
When the foaming agent (D) consists only of water, the amount of water is preferably 10 parts by mass or less with respect to the total of the polyol (A) and other high molecular weight active hydrogen compounds (100 parts by mass). ˜8 parts by mass is particularly preferred.

<Crosslinking agent (E)>
In the present invention, a crosslinking agent (E) may be used as necessary. By using the crosslinking agent (E), effects such as improvement in the hardness of the flexible foam can be obtained.
As the crosslinking agent (E), a compound having two or more groups having active hydrogen (referred to herein as active hydrogen groups) is used. Examples of the active hydrogen group include a hydroxyl group, a primary amino group, and a secondary amino group. A crosslinking agent (E) may be used individually by 1 type, and may use 2 or more types together. However, what is contained in the said polyol (A1) and the below-mentioned foam breaker (F) shall not be contained in a crosslinking agent (E).
As the crosslinking agent (E), it is preferable to use the following first crosslinking agent (E1) and / or second crosslinking agent (E2).

[First cross-linking agent (E1)]
The first cross-linking agent (E1) is a polyoxyalkylene polyol having two or more active hydrogen groups and obtained through a step of ring-opening addition polymerization of alkylene oxide in the presence of a catalyst or without using a catalyst. And it is preferable to consist of a compound whose hydroxyl value is 160-1,000 mgKOH / g.
Examples of the first crosslinking agent (E1) include a low molecular weight polyoxyalkylene polyol obtained by adding an alkylene oxide to a polyhydric alcohol.
Specific examples include bisphenol A-alkylene oxide adduct, glycerin-alkylene oxide adduct, trimethylolpropane-alkylene oxide adduct, pentaerythritol-alkylene oxide adduct, sorbitol-alkylene oxide adduct, sucrose-alkylene oxide adduct. Products, aliphatic amine-alkylene oxide adducts, alicyclic amine-alkylene oxide adducts, heterocyclic polyamine-alkylene oxide adducts, and aromatic amine-alkylene oxide adducts. Among these, a sorbitol-alkylene oxide adduct, a pentaerythritol-alkylene oxide adduct, and a trimethylolpropane-alkylene oxide adduct are preferable in terms of improving the hardness of the resulting flexible foam.
The number of active hydrogen groups in the first crosslinking agent (E1) is preferably 2 to 8, and particularly preferably 3 to 6.5. The hydroxyl value of the first crosslinking agent (E1) is preferably 160 to 1,000 mgKOH / g, particularly preferably 160 to 600 mgKOH / g.

[Second cross-linking agent (E2)]
The second cross-linking agent (E2) is preferably a compound having no polyether chain, having two or more active hydrogen groups, and having a hydroxyl value greater than 1,000 mgKOH / g.
Examples of the second crosslinking agent (E2) include polyhydric alcohols and amine crosslinking agents having a hydroxyl value greater than 1,000 mgKOH / g. The amine-based crosslinking agent is preferably an aromatic polyamine, an aliphatic polyamine, or an alicyclic polyamine.
Polyhydric alcohols include monoethanolamine, diethanolamine, ethanolamines of triethanolamine, ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol , Glycerin and N-alkyldiethanol. Ethanolamines may be produced by reacting ammonia or concentrated aqueous ammonia with ethylene oxide in the presence of a catalyst during the production thereof, but the ethanolamines finally obtained do not have a polyether chain. It is contained in the second cross-linking agent (E2).

As the aromatic polyamine, an aromatic diamine is preferable. As the aromatic diamine, an aromatic diamine having one or more substituents selected from an alkyl group, a cycloalkyl group, an alkoxy group, an alkylthio group, and an electron-withdrawing group in an aromatic nucleus to which an amino group is bonded is preferable. Diaminobenzene derivatives are particularly preferred.
The substituent other than the electron-withdrawing group is preferably bonded to 2 to 4 aromatic nuclei to which the amino group is bonded, and is bonded to one or more of the ortho positions with respect to the binding site of the amino group. It is more preferable that it is bonded to all.
It is preferable that one or two electron-withdrawing groups are bonded to the aromatic nucleus to which the amino group is bonded. An electron-withdrawing group and another substituent may be bonded to one aromatic nucleus.
The number of carbon atoms in the alkyl group, alkoxy group and alkylthio group is preferably 4 or less.
As the cycloalkyl group, a cyclohexyl group is preferable.
As the electron withdrawing group, a halogen atom, a trihalomethyl group, a nitro group, a cyano group, and an alkoxycarbonyl group are preferable, and a chlorine atom, a trifluoromethyl group, or a nitro group is particularly preferable.

Aliphatic polyamines can be obtained by converting some or all of the hydroxyl groups of diaminoalkanes having 6 or less carbon atoms, polyalkylene polyamines having a hydroxyl value greater than 1,000 mgKOH / g, and low molecular weight polyoxyalkylene polyols to amino groups. Examples thereof include polyamines having a hydroxyl value larger than 1,000 mgKOH / g and aromatic compounds having two or more aminoalkyl groups.
Examples of the alicyclic polyamine include cycloalkanes having two or more amino groups and / or aminoalkyl groups.

  Specific examples of the amine-based crosslinking agent include 3,5-diethyl-2,4 (or 2,6) -diaminotoluene (DETDA), 2-chloro-p-phenylenediamine (CPA), 3,5-dimethylthio- 2,4 (or 2,6) -diaminotoluene, 1-trifluoromethyl-3,5-diaminobenzene, 1-trifluoromethyl-4-chloro-3,5-diaminobenzene, 2,4-toluenediamine, 2,6-toluenediamine, bis (3,5-dimethyl-4-aminophenyl) methane, 4,4-diaminodiphenylmethane, ethylenediamine, m-xylenediamine, 1,4-diaminohexane, 1,3-bis (amino) Methyl) cyclohexane, isophoronediamine and the like, and diethyltoluenediamine [that is, 3,5-diethyl-2, (Or 2,6) - one or more mixture of diaminotoluene, dimethylthiotoluenediamine, monochlorodisilane aminobenzene, diaminobenzene derivative such as trifluoromethyl-diaminobenzene are preferred.

  The number of active hydrogen groups in the second crosslinking agent (E2) is preferably 2 to 8, and particularly preferably 2 to 6. The hydroxyl value of the second crosslinking agent (E2) is preferably more than 1,000 to 2,000 mgKOH / g, particularly preferably 1,100 to 1,900 mgKOH / g.

0.1-20 mass parts is preferable with respect to the sum total (100 mass parts) of a polyol (A) and another high molecular weight active hydrogen compound, and, as for the total usage-amount of a crosslinking agent (E), 0.2-15 Mass parts are more preferable, and 0.3 to 10 parts by mass are particularly preferable. When it is at least the lower limit of the above range, an appropriate hardness can be imparted to the flexible foam, and the foaming behavior is stabilized. If it is below the upper limit of the above range, flexibility can be imparted to the flexible foam, and mechanical properties such as tear strength, tensile strength and elongation will be good.
When using together the 1st crosslinking agent (E1) and the 2nd crosslinking agent (E2) as a crosslinking agent (E), the mass of the 1st crosslinking agent (E1) and the 2nd crosslinking agent (E2) The ratio (E1) / (E2) is preferably 90/10 to 10/90, particularly preferably 90/10 to 50/50.

<Foam breaker (F)>
In the present invention, a foam breaker (F) may be used as necessary. The foam breaker (F) is a component for lowering the closed cell ratio by rupturing some of the bubbles of the flexible foam. By using the foam breaker (F), the air permeability of the flexible foam can be adjusted according to the purpose.
The foam breaker (F) is a polyether polyol obtained by subjecting EO or a mixture of EO and PO to ring-opening addition polymerization in the presence of an alkali metal hydroxide catalyst as an initiator. A polyether polyol having an average number of hydroxyl groups of 2 to 8 and a hydroxyl value of 20 to 200 mgKOH / g is used.
When the polyether polyol as the foam breaker (F) is 100% by mass, the total of oxyethylene groups contained in the foam breaker (F) is 50 to 100% by mass, preferably 60 to 100% by mass. 65 to 95% by mass is particularly preferable. When the total of the oxyethylene groups is at least the lower limit of the above range, the closed cell ratio of the flexible foam can be reduced.
One type of foam breaker (F) may be used, or two or more types may be used in combination.

2-8 are preferable and, as for the average number of hydroxyl groups of a foam breaker (F), 2-6 are especially preferable. When the average number of hydroxyl groups is not less than the lower limit of the above range, a flexible foam having good hardness can be obtained. A flexible foam with favorable durability can be obtained as it is below an upper limit.
The hydroxyl value of the foam breaker (F) is preferably 20 to 200 mgKOH / g, more preferably 24 to 150 mgKOH / g, still more preferably 24 to 100 mgKOH / g, and particularly preferably 24 to 60 mgKOH / g. When the hydroxyl value is at least the lower limit of the above range, the polyol system liquid is difficult to increase in viscosity and easy to handle. A flexible foam with favorable durability can be obtained as it is below an upper limit.
0.1-10 mass parts is preferable with respect to the total (100 mass parts) of a polyol (A) and another high molecular weight active hydrogen compound, and the total usage-amount of a foam breaker (F) is 0.1-0.1 mass parts. 7 mass parts is more preferable, and 0.1-5 mass parts is especially preferable.

<Foam stabilizer (G)>
As the foam stabilizer (G) in the present invention, dimethylpolysiloxane represented by the above formula (I) (the average value of n in the formula is 1 to 10. Hereinafter, it may be referred to as dimethylpolysiloxane (I). Yes).
In addition, even if dimethylpolysiloxane (I) is a single compound produced under a certain production condition, since there is a molecule having a different n value in the single compound, n is an average value. It is represented by
When the average value of n in the formula (I) is 10 or less, deterioration of mechanical properties due to the use of the stored polyol system liquid can be suppressed without impairing the physical properties of the foam. In view of stabilization of foaming of the flexible foam, the lower limit of the average value of n is preferably 1 or more, more preferably 2 or more, and particularly preferably 3 or more.
Dimethylpolysiloxane (I) may be used alone or in combination of two or more different n average values. When using 2 or more types together, the average value of n of each dimethylpolysiloxane (I) should just be in said range.
Dimethylpolysiloxane (I) is commercially available.

The amount of the foam stabilizer (G) used is preferably 0.001 to 2 parts by mass, and 0.005 to 1 part by mass with respect to the total (100 parts by mass) of the polyol (A) and other high molecular weight active hydrogen compounds. Part is more preferable, and 0.01 to 0.8 part by mass is particularly preferable.
When the amount of the foam stabilizer (G) used is not more than the upper limit of the above range, a flexible foam having good durability can be obtained. If it is at least the lower limit of the above range, foaming can be carried out stably.

<Other ingredients>
In addition, as a compounding agent used arbitrarily, a filler, a stabilizer, a coloring agent, a flame retardant, etc. are mentioned. As these, known ones can be used as appropriate.

<Method for producing flexible polyurethane foam>
The method for producing a flexible polyurethane foam of the present invention comprises a polyol (A), a polyisocyanate compound (B), a catalyst (C), a foaming agent (D), a crosslinking agent (E), and other components blended as necessary. It has a foaming process to react.
The preferred combination of combinations is as follows.
Polyol (A1): 50 to 100% by mass in the polyol (A),
Polyol (A21): 1 to 50% by mass in the polyol (A),
Crosslinking agent (E): 1 to 15 parts by mass with respect to the total (100 parts by mass) of polyol (A) and other polymer active hydrogen compounds,
Catalyst (C): 0.1 to 1 part by mass with respect to the total (100 parts by mass) of polyol (A) and other polymer active hydrogen compounds,
Foam stabilizer (G): 0.001 to 5 parts by mass with respect to the total (100 parts by mass) of the polyol (A) and other polymer active hydrogen compounds,
Foaming agent (D): 0.1 to 5 parts by mass with respect to the total (100 parts by mass) of polyol (A) and other polymer active hydrogen compounds,
Polyisocyanate compound (B): 90 to 110 in terms of isocyanate index.

  As a method of the foaming step, the polyol (A), the polyisocyanate compound (B), the catalyst (C), the foaming agent (D), the cross-linking agent (E) and, if necessary, blended in a sealed mold. And a method (foaming method) of foaming a liquid (reactive mixture) containing other components, and a method (slab method) of foaming the reactive mixture in an open system.

[Mold method]
As the molding method, a method of directly injecting the reactive mixture into a sealed mold (reaction injection molding method) or a method of sealing after injecting the reactive mixture into an open mold is preferable. As the latter method, a method of injecting the reactive mixture into the mold using a low pressure foaming machine or a high pressure foaming machine is preferable.
As the high-pressure foaming machine, a type in which two liquids are mixed is preferable. Of the two liquids, one liquid is a polyisocyanate compound (B), and the other liquid is a mixture of all components other than the polyisocyanate compound (B). Depending on the case, it may be a type in which three liquids are mixed, each containing a catalyst (C) or a foam breaker (F) (usually dispersed or dissolved in another polyol).

As for the temperature of the reactive mixture used for a foaming process, 10-40 degreeC is preferable. If this temperature is 10 degreeC or more, the viscosity of a reactive mixture will not become high too much and the mixability of a liquid will become favorable. If this temperature is 40 degrees C or less, the reactivity will not become high too much and a moldability etc. will become favorable.
The mold temperature is preferably 10 ° C to 80 ° C, particularly preferably 30 ° C to 70 ° C.
The curing time is preferably 3 to 20 minutes, more preferably 3 to 10 minutes, and particularly preferably 1 to 7 minutes. If the curing time is 1 minute or longer, curing can be performed sufficiently. If the curing time is 20 minutes or less, the productivity will be good.

[Slab method]
Examples of the slab method include known methods such as a one-shot method, a semi-prepolymer method, and a prepolymer method. A known production apparatus can be used for producing the flexible polyurethane foam.

  According to the production method of the present invention, by using the polyol (A1) using a DMC catalyst at the time of polymerization, it is possible to obtain a flexible foam excellent in mechanical properties and having good tear strength, tensile strength and elongation of the flexible foam. . Therefore, when used as a seat cushion for automobiles or a cushion for furniture, deterioration of the flexible foam due to human movement is well suppressed.

Further, according to the knowledge of the present inventors, when a flexible polyurethane foam is produced using the polyol (A1), if a conventional silicone-based foam stabilizer is used, the machine of the foam by using the stored polyol system liquid is used. Degradation of characteristics may occur.
On the other hand, according to the present invention, among the dimethylpolysiloxanes represented by the formula (I), the use of a specific foam stabilizer (G) having a particularly small average value of n makes it possible to improve the flexibility of the flexible foam. The physical properties can be obtained, and the deterioration of mechanical properties due to the use of the stored polyol system liquid can be effectively suppressed.
The reason why such an effect is obtained is not clear, but when mechanical properties deteriorate due to the use of a stored polyol system liquid using a conventional silicone foam stabilizer, the cells become coarse. The molecular structure of the foam stabilizer (G) in the present invention is the foam stabilizer (G) and the foaming agent (D) in the polyol system liquid in the presence of the polyol (A1) using the DMC catalyst during polymerization. It is considered that the dispersion state of the cell changes, and as a result, cell coarsening is suppressed.

The flexible foam manufactured by the manufacturing method of the present invention includes automotive interior materials (seat cushions, seat backrests, headrests, armrests, etc.), railway vehicle interior materials, bedding and furniture cushions (mattresses, sofas, chairs). For cushions).
In particular, since it is excellent in hardness and mechanical properties, it is suitable as an automobile seat cushion or furniture cushion.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
The measurement was performed by the following method.
[Hydroxyl value]
The hydroxyl value of the polyol was measured according to JIS K1557 (2007 edition) (titration method).

[Number average molecular weight and mass average molecular weight]
The number average molecular weight (Mn) and the mass average molecular weight (Mw) were measured by the following methods.
GPC of several types of monodispersed polystyrene polymers with different degrees of polymerization that are commercially available as standard samples for molecular weight measurement were measured using a commercially available GPC measuring device (HLC-8220 GPC, manufactured by Tosoh Corporation). A calibration curve was prepared based on the relationship between molecular weight and retention time (retention time).
The sample was diluted to 0.5 mass% with tetrahydrofuran and passed through a 0.5 μm filter, and then GPC of the sample was measured using the GPC measurement apparatus.
The number average molecular weight (Mn) and the mass average molecular weight (Mw) of the sample were determined by computer analysis of the GPC spectrum of the sample using the calibration curve.
[Classification rate]
The ratio of primary hydroxyl groups (primaryization rate) of hydroxyl groups at the molecular ends of polyols was measured using an α-600 (600 MHz) superconducting nuclear magnetic resonance (NMR) apparatus manufactured by JEOL Ltd., using deuterated chloroform as a solvent. did. The ¹³ C-NMR spectrum of the polyol was taken, and the ratio of primary hydroxyl groups (primary ratio, unit: mol%) was determined from the signal ratio between the methyl group bonded to the primary hydroxyl group and the methyl group bonded to the secondary hydroxyl group.

Each component described in Table 1 will be described.
[Preparation Example 1: Preparation of TBA-DMC catalyst]
A zinc hexacyanocobaltate complex (DMC catalyst) coordinated with tert-butyl alcohol (hereinafter referred to as TBA) was prepared as follows.
An aqueous solution consisting of 10.2 g of zinc chloride and 10 g of water was placed in a 500 mL flask. While stirring the aqueous zinc chloride solution at a rotational speed of 300 revolutions per minute, an aqueous solution consisting of 4.2 g of potassium hexacyanocobaltate (K ₃ Co (CN) ₆ ) and 75 g of water was added over 30 minutes. It was dripped in. During this time, the mixed solution in the flask was kept at 40 ° C. After the dropwise addition of the aqueous potassium hexacyanocobaltate solution was completed, the mixture in the flask was stirred for another 30 minutes, and then a mixture consisting of 80 g of tert-butyl alcohol, 80 g of water, and 0.6 g of polyol P was added. Stir at 30 ° C. for 30 minutes and then at 60 ° C. for 60 minutes.
Polyol P was obtained by subjecting PO to ring-opening addition polymerization to propylene glycol in the presence of a KOH catalyst, and obtained by dealkal purification and having an average number of hydroxyl groups of 2 and a number average molecular weight (Mn) of 2 per molecule. 000 polyoxypropylene diol.

The obtained mixture was filtered under pressure (0.25 MPa) using a circular filter plate having a diameter of 125 mm and a quantitative filter paper for fine particles (ADVANTEC, No. 5C), and a solid containing a composite metal cyanide complex (Cake) was obtained.
The cake was transferred to a flask, and a mixed solution consisting of 36 g of TBA and 84 g of water was added and stirred for 30 minutes, followed by pressure filtration under the same conditions as above to obtain a cake.
The cake was transferred to a flask, and a mixed solution composed of 108 g of TBA and 12 g of water was further added and stirred for 30 minutes to obtain a slurry in which the composite metal cyanide complex catalyst was dispersed in the TBA-water mixture. After adding 120 g of polyol P to the slurry, volatile components were distilled off under reduced pressure at 80 ° C. for 3 hours and further at 115 ° C. for 3 hours to obtain a slurry-like DMC catalyst (TBA-DMC catalyst). It was. The concentration (active component concentration) of the DMC catalyst (solid catalyst component) contained in the slurry was 5.33% by mass.

[Production Example 1: Production of polyol (A1-1)]
The initiator (a1) used in this example was subjected to ring-opening addition polymerization of PO to glycerin using a KOH catalyst, and further purified using Kyowad 600S (product name, synthetic adsorbent, manufactured by Kyowa Chemical Industry Co., Ltd.). Manufactured. This is a polyoxypropylene triol having a number average molecular weight (Mn) of 1,500 and a hydroxyl value of 112 mgKOH / g.
The pressure-resistant reaction vessel is made of stainless steel provided with a stirrer to which one set of anchor blades and two sets of 45 ° inclined two-blade paddle blades are attached, and a cooling pipe through which cooling water flows is provided inside the vessel ( A pressure resistant reactor (capacity 10 L, diameter 200 mm, height 320 mm) of JIS-SUS-316) was used.
The temperature of the reaction solution was measured with a thermometer installed at the lower part inside the pressure-resistant reaction vessel.

First, 1,000 g of the initiator (a1) and the TBA-DMC catalyst slurry produced in Preparation Example 1 were charged into a pressure resistant reaction vessel to obtain a reaction solution. The amount of TBA-DMC catalyst slurry charged was such that the metal concentration of the TBA-DMC catalyst in the reaction solution (hereinafter referred to as initial catalyst metal concentration) was 46 ppm.
Next, after replacing the inside of the pressure-resistant reaction vessel with nitrogen, the reaction solution was heated with stirring, and when reaching 135 ° C. (initial temperature), the heating was stopped, and stirring was continued while 120 g of PO was added to 100 parts by mass of the initiator. In contrast, 12 parts by mass) was supplied into the pressure-resistant reaction vessel and reacted.
When PO was supplied into the pressure-resistant reaction vessel (start of the initial activation process), the internal pressure of the pressure-resistant reaction vessel once increased and then gradually decreased to be the same as the pressure inside the pressure-resistant reaction vessel immediately before supplying PO. This was confirmed (end of the initial activation process). During this time, when the internal pressure began to decrease, the temperature of the reaction solution once increased, and then gradually decreased. The maximum temperature of the reaction solution was 165 ° C. In this example, cooling was performed after the temperature rise of the reaction solution stopped. Further, the time required for this initial activation process was 30 minutes.

Thereafter, PO was supplied for reaction, and then EO was added to the end using a KOH catalyst (addition polymerization step). That is, while stirring the reaction solution, it was confirmed that the reaction solution had been cooled to 135 ° C., and 4,728 g of PO was supplied into the pressure-resistant reaction vessel while maintaining 135 ° C. After confirming that the internal pressure did not change and the reaction was completed, 20g of KOH catalyst (active ingredient concentration 0.3% with respect to the final product) was added, and alcoholate was formed by dehydration at 120 ° C for 2 hours. It was. Subsequently, 950 g of EO (31.8 mol per mol of initiator) was additionally supplied into the pressure-resistant reaction vessel while keeping the reaction solution at 120 ° C. After confirming that the internal pressure did not change and the reaction was completed, the catalyst was neutralized and removed using Kyowad 600S (product name, synthetic adsorbent, manufactured by Kyowa Chemical Industry Co., Ltd.).
The polyol (A1-1) thus obtained had an average number of hydroxyl groups of 3, a hydroxyl value of 16.8 mgKOH / g, a number average molecular weight (Mn) of 13,228, an unsaturation of 0.007 meq / g, and a molecular weight distribution ( Mw / Mn) was 1.045, the oxyethylene group content was 14% by mass, and the primary rate was 93 mol%.

[Polymer-dispersed polyol (A21-1)]
In a base polyol having an average number of hydroxyl groups of 3, a hydroxyl value of 34 mg KOH / g, and containing 14.5% by mass of oxyethylene groups at the ends, 77.5% by mass and 22.5% of acrylonitrile and styrene, respectively. A polymer-dispersed polyol (A21-1) having a hydroxyl value of 24 mgKOH / g, obtained by polymerization at a mass%, was used. The polymer particle content in the polymer-dispersed polyol (A21-1) was 35% by mass.
The base polyol is obtained by subjecting an initiator to ring-opening addition polymerization of PO in the presence of a KOH catalyst and then ring-opening addition polymerization of EO. The initiator is a polyether polyol having a number average molecular weight (Mn) of 1,300 obtained by ring-opening addition polymerization of PO to glycerin using a KOH catalyst.
That is, 1,767 g of the initiator, 20 g of the KOH catalyst (active ingredient concentration of 0.3% with respect to the final product), and 4,641 g of PO are charged into the same reaction vessel as in Production Example 1 at 120 ° C. The mixture was stirred for 8 hours for ring-opening addition polymerization. Thereafter, 1,141 g of EO was further added, and the mixture was stirred at 110 ° C. for 1.5 hours for ring-opening addition polymerization, and the resulting polyoxypropyleneoxyethylene polyol was used as a base polyol.

[Crosslinking agent (E1-1)]
Polyether having a hydroxyl value of 450 mgKOH / g and an oxyethylene group content of 28% by mass obtained by subjecting sorbitol to ring-opening addition polymerization of PO in the presence of a KOH catalyst and subsequently ring-opening addition polymerization of EO Polyol.
[Crosslinking agent (E2-1)]
Diethanolamine.
[Foaming agent (F-1)]
A polyether polyol having a hydroxyl value of 48 mgKOH / g and an oxyethylene group content of 80% by mass obtained by ring-opening addition polymerization of a mixture of PO and EO with glycerin in the presence of a KOH catalyst.
[Catalyst (C-1)]
A dipropylene glycol (DPG) solution containing 33% by mass of triethylenediamine (manufactured by Tosoh Corporation, trade name: TEDA L33).
[Catalyst (C-2)]
A DPG solution containing 70% by mass of bis- (2-dimethylaminoethyl) ether (manufactured by Tosoh Corporation, trade name: TOYOCAT ET).

[Foam stabilizer (G-1)]
Product name: KF-96A-6cs, manufactured by Shin-Etsu Chemical Co., Ltd. Dimethylpolysiloxane represented by the above formula (I) and having an average value of n of 7.3. The kinematic viscosity at 25 ° C. is 6 mm / s.
[Foam stabilizer (G-2)]
Product name: KF-96A-5cs, manufactured by Shin-Etsu Chemical Co., Ltd. Dimethylpolysiloxane represented by the above formula (I) and having an average value of n of 7.0. The kinematic viscosity at 25 ° C. is 5 mm / s.
[Foam stabilizer (Comparison 1)]
Product name: KF-96A-100cs, manufactured by Shin-Etsu Chemical Co., Ltd. Dimethylpolysiloxane represented by the above formula (I) and having an average value of n of 83. The kinematic viscosity at 25 ° C. is 100 mm / s.
[Foam stabilizer (Comparison 2)]
Product name: SZ-1325, manufactured by Toray Dow Corning.
[Foaming agent (D-1)]
water.
[Polyisocyanate compound (B-1)]
A mixture of 80% by mass of TDI-80 (isomer ratio of 80% by mass of 2,4-TDI and 20% by mass of 2,6-TDI) and 20% by mass of polymethylene polyphenyl polyisocyanate (commonly called polymeric MDI). Product name: Coronate 1021 (manufactured by Nippon Polyurethane Industry Co., Ltd.).

<Manufacture of flexible polyurethane foam>
[Examples 1-4, Examples 11-12]
A flexible polyurethane foam was produced with the formulation shown in Table 1. Examples 1 to 4 are examples, and examples 11 to 12 are comparative examples.
The unit of the blending amount in Table 1 is represented by an isocyanate index (indicated in the table as [INDEX]) for the polyisocyanate compound (B). The others are parts by mass.

First, among the formulations shown in the table, a predetermined amount of each component excluding the polyisocyanate compound (B) is weighed into a 2 L capacity plastic container and rotated at 3,000 revolutions per minute using a mixer with stirring blades. The mixture was stirred and mixed for 30 seconds to prepare a polyol system solution.
Next, a predetermined amount of the polyisocyanate compound (B) was weighed into a plastic container having a capacity of 500 cc.
(Before storage)
The polyol system solution prepared immediately above was adjusted to a liquid temperature of 30 ° C. and the polyisocyanate compound (B) was adjusted to a liquid temperature of 25 ° C., and then the polyisocyanate compound (B) was added to the polyol system solution, and the mixer was used. A reactive mixture was prepared by stirring and mixing for 5 seconds at a rotational speed of 3,000 revolutions per minute. The reactive mixture immediately after preparation was poured into an aluminum mold in which the upper mold was adjusted to a mold temperature of 60 ° C., 400 mm in length, 100 mm in thickness or 70 mm in thickness, and the upper mold was quickly closed and sealed. Foaming and molding were performed at After 6 minutes from the start of molding, the upper mold was opened to obtain a flexible polyurethane foam. In addition, a shaping | molding start shows the time of starting stirring and mixing a polyol system liquid and a polyisocyanate compound (B).

(After 6 days storage)
The polyol system solution prepared above was stored for 6 days (144 hours) in a state of standing in an atmosphere at 50 ° C., and then a flexible polyurethane foam was produced using the polyol system solution under the same conditions as described above.

[Evaluation method]
About the flexible polyurethane foam obtained using the polyol system liquid before storage, total density, core density, 25% ILD hardness, 50% ILD hardness, 65% ILD hardness, air permeability of the core part, overall rebound resilience, The core resilience, tear strength, tensile strength, elongation, compression set, wet heat compression set (durability) and hysteresis loss rate (200 mm diameter press panel) conform to JIS K6400 (1997 edition). Measured.
For the stress relaxation rate, the stress relaxation rate (%) after 5 minutes of 196 N pressurization in a 314 cm ² disk was measured.
The core density and the rebound resilience of the core portion were evaluated using a sample cut out from the center of the obtained foam with dimensions of 100 mm in length and width and 50 mm in height.
In the measurement of ILD hardness, the initial thickness, which is the foam thickness when a 5N load is applied, was measured.
SAG-FACTOR, which is the ratio of 65% ILD hardness to 25% ILD hardness, was determined. The smaller this value is, the less likely the bottom feeling of the obtained flexible polyurethane foam is.
As vibration characteristics, resonance frequency, resonance magnification (absolute displacement measurement), 6 Hz resonance transmission rate, and 10 Hz resonance transmission rate were measured by a method based on JASO B8407-82. As a measurement condition of the vibration characteristics, a Tekken type (490N) was used as a pressure plate, and the total amplitude of vibration was 5 mm.
The compression set and the wet heat compression set indicate that the smaller the value, the better the durability.
If the value of the resonance frequency is 5 Hz or less, when used as a seat cushion foam for automobiles, vibrations in a frequency range sensitive to humans are efficiently attenuated, and a good riding comfort can be obtained. The smaller the resonance transmissibility, the transmissibility of 6 Hz or 10 Hz, the better the ride comfort.

The initial thickness, 25% ILD hardness, and mechanical properties (tear strength, tensile strength, and elongation) in IDL hardness were measured in the same manner as described above for a flexible polyurethane foam produced using a polyol system solution stored for 6 days. .
For each measured value of mechanical properties, a ratio (unit:%) based on the value before storage was determined based on the following formula.
Mechanical property ratio (%) = {(measured value after storage for 6 days) / (measured value before storage)} × 100

As shown in the results of Table 2, Examples 1-4 using the foam stabilizer (G) represented by the above formula (I) and having an average value of n of 9.5 or 9.0 are represented by the formula ( Compared to Example 12 using the silicone-based foam stabilizer containing no dimethylpolysiloxane represented by I) (Comparative 2), the decrease in mechanical properties due to the use of the stored polyol system liquid is small.
Moreover, the physical properties of the flexible polyurethane foam obtained in Examples 1 to 4 were good.
Even in the compound represented by the above formula (I), collapse (collapse) occurred in Example 11 using the foam stabilizer (Comparative 1) having a large average value of n of 85. The reason can be considered that the communication rate of the flexible foam has become very high.

Claims (10)

A step of reacting the polyol (A) with the polyisocyanate compound (B) in the presence of the catalyst (C), the foaming agent (D), and the foam stabilizer (G),
The polyol (A) contains 2 to 100% by mass of the following polyol (A1) in the total amount of the polyol (A),
A method for producing a flexible polyurethane foam, wherein the foam stabilizer (G) is dimethylpolysiloxane represented by the following formula (I).
Polyol (A1): obtained by undergoing ring-opening addition polymerization of alkylene oxide in the presence of a double metal cyanide complex catalyst as an initiator, having an average number of hydroxyl groups of 2 to 8 and a hydroxyl value of 5 to 45 mgKOH / g Polyether polyol.

The manufacturing method of the flexible polyurethane foam of Claim 1 which the said polyol (A1) consists of a polyether polyol obtained with the manufacturing method of the following polyol (A1).
Production method of polyol (A1): A part of the alkylene oxide is added to a reaction solution containing an initiator and a double metal cyanide complex catalyst in an amount of 5 to 20 parts per 100 parts by mass of the initiator contained in the reaction solution. There are an initial activation step (a) for supplying and reacting so as to be part by mass, and an additional polymerization step (b) for additionally supplying an alkylene oxide and performing a polymerization reaction after the initial activation step (a). The initial temperature of the reaction liquid immediately before the start of supplying a part of the alkylene oxide is 120 to 165 ° C., and the maximum temperature of the reaction liquid in the initial activation step (a) is 15 from the initial temperature. A manufacturing method which is a temperature higher by 50 ° C to 50 ° C.   The method for producing a flexible polyurethane foam according to claim 1 or 2, wherein the composite metal cyanide complex catalyst has tert-butyl alcohol as an organic ligand.   The manufacturing method of the flexible polyurethane foam as described in any one of Claims 1-3 which contains 50-100 mass% of said polyether polyols (A1) in the whole quantity of the said polyol (A).   The manufacturing method of the flexible polyurethane foam as described in any one of Claims 1-4 with which the said foaming agent (D) consists only of water.   The manufacturing method of the flexible polyurethane foam as described in any one of Claims 1-5 in which the said polyol (A) contains polymer fine particle (H) by content of more than 0 mass% and 30 mass% or less. The manufacturing method of the flexible polyurethane foam of Claim 6 which contains the following polymer dispersion | distribution polyol (A21) in the said polyol (A).
Polymer-dispersed polyol (A21): A polymer-dispersed polyol in which the polymer fine particles (H) are dispersed in a polyol (A2) that is a polyol other than the polyol (A1).   The usage-amount of the said foam stabilizer (G) is 0.001-2 mass parts with respect to the sum total (100 mass parts) of a polyol (A) and another high molecular weight active hydrogen compound. The manufacturing method of the flexible polyurethane foam as described in any one of these.   The sheet | seat using the flexible polyurethane foam manufactured by the method as described in any one of Claims 1-8.   The seat according to claim 9, which is used for an automobile.