JP2006282854A - Method for producing flexible urethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a flexible urethane foam in which molding defect can be suppressed and further, lowering of compression recovery property can be suppressed when a flexible urethane foam is formed even when increasing the amount of non-halogen-based flame retardant added. <P>SOLUTION: In the method for producing a flexible urethane foam by reacting a polyol component with a polyisocyanate component, a foam stabilizer and a foaming agent in the presence of a non-halogen-based flame retardant, the polyol component comprises a polyfunctional polyether polyol obtained by adding ethylene oxide and propylene oxide to an organic compound having at least three active hydrogen and at least an aminoplast-based flame-retardant polymer graft polyol, and the non-halogen-based flame retardant contains at least an organophosphate-based flame retardant and a metal hydroxide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a flexible urethane foam.

Since flexible urethane foam has excellent elastic force and compression resilience, it is used for applications such as cushioning materials for furniture, bedding, automobile members, etc. and gaskets for electronic equipment parts in recent years. Yes. When used in these applications, flame retardancy is required.
As a method for making the flexible urethane foam flame-retardant, a method for imparting flame retardancy by adding a flame retardant has been conventionally used. As the flame retardant, a halogen having excellent flame retardancy is used. Series flame retardants are widely used.

However, incineration of the cushion material and the like to which the halogen flame retardant is added generates dioxins and the like, and its use is being restricted from the viewpoint of environmental problems.
Therefore, in place of the halogen flame retardant, a non-halogen flame retardant (for example, an organic phosphoric acid flame retardant) is being used.
Since the non-halogen flame retardant is inferior in flame retardancy compared to the halogen flame retardant, the amount of the non-halogen flame retardant needs to be increased.

  In the flexible urethane foam, when the amount of the non-halogen flame retardant added is increased in order to obtain the same flame retardance as the halogen flame retardant, a molding defect occurs when the flexible urethane foam is molded. There is a problem that the compressibility is reduced (Patent Document 1).

  Therefore, even when the amount of the non-halogen flame retardant added is increased, when molding a flexible urethane foam, there is a method suitable for the production of a flexible urethane foam that can suppress molding defects and further suppress a decrease in compression recovery property. It is requested.

JP 2002-198679 A

  In view of the above problems and demands, the present invention is a soft material that can suppress molding defects and can further suppress a decrease in compression recovery property when a flexible urethane foam is molded even if the amount of non-halogen flame retardant added is increased. It is an object to provide a method suitable for production of urethane foam.

  The inventors of the present invention have intensively studied to solve the above problems, and as a result, have found that the above problems can be solved by using a polyether component containing a polyfunctional polyether polyol, thereby completing the present invention. It came.

  That is, the present invention relates to a method for producing a flexible urethane foam in which a polyol component, a polyisocyanate component, a foam stabilizer, and a foaming agent are reacted in the presence of a non-halogen flame retardant, wherein the polyol component contains at least 3 active hydrogens. A polyfunctional polyether polyol obtained by adding ethylene oxide and propylene oxide to an organic compound having two or more and an aminoplast flame retardant polymer graft polyol, and the non-halogen flame retardant as an organic phosphate ester flame retardant; Provided is a method for producing a flexible urethane foam, comprising at least a metal hydroxide.

  Polyol component, polyisocyanate component, foam stabilizer and foam containing polyfunctional polyether polyol obtained by adding ethylene oxide and propylene oxide to an organic compound having at least three active hydrogens and aminoplast flame retardant polymer graft polyol By reacting the agent in the presence of a non-halogen flame retardant containing at least an organophosphate flame retardant and a metal hydroxide, molding defects of flexible urethane foam can be suppressed, and compression recovery is further reduced. Can be suppressed.

In the present invention, it is preferable that 20 to 80 parts by weight of the polyfunctional polyether polyol is contained in 100 parts by weight of the polyol component.
By using such a polyol component, the compression recovery property and flame retardancy of the resulting flexible urethane foam are improved.

Furthermore, in the present invention, the polyfunctional polyether polyol preferably has an average functional group number of 3 to 4, a hydroxyl value of 20 to 50 mgKOH / g, and an ethylene oxide content of 5 to 40% by weight.
By using such a polyfunctional polyether polyol, a flexible urethane foam having good moldability can be obtained.

Moreover, in this invention, the compounding quantity of the said organophosphate ester flame retardant is 5-30 weight part with respect to 100 weight part of said polyol components, and the compounding quantity of the said metal hydroxide is the said polyol. It is preferable that it is 5-30 weight part with respect to 100 weight part of components.
By using the organic phosphate ester flame retardant and the metal hydroxide in such a blending amount, the flame resistance of the obtained flexible urethane foam is improved.

According to the method for producing a flexible urethane foam of the present invention, even if the amount of non-halogen flame retardant added is increased in order to obtain the same flame retardance as that of a halogen flame retardant, molding defects can be suppressed, and further compression restoration can be achieved. It can suppress that property falls.
In addition, according to the method for producing a flexible urethane foam of the present invention, since no halogen-based flame retardant is used, generation of dioxins can be prevented even if the flexible urethane foam obtained by the production method is incinerated.

  In the method for producing a flexible urethane foam of the present invention, a polyol component, a polyisocyanate component, a foam stabilizer, and a foaming agent are reacted in the presence of a non-halogen flame retardant.

  The polyol component contains a polyfunctional polyether polyol obtained by adding ethylene oxide and propylene oxide to an organic compound having at least three active hydrogens and an aminoplast flame-retardant polymer graft polyol.

Content of the said polyfunctional polyether polyol in the said polyol component is 20-80 weight part in this polyol component 100 weight part, Preferably it is 40-60 weight part.
When the content of the polyfunctional polyether polyol is less than 20 parts by weight, the compression recovery property may be deteriorated.
Moreover, when content of this polyfunctional polyether polyol exceeds 80 weight part, there exists a possibility that sufficient flame retardance may not be obtained.

The polyfunctional polyether polyol has an average functional group number of 3 to 4, a hydroxyl value of 25 to 50 mgKOH / g, and an ethylene oxide content of 5 to 40% by weight, preferably an average functional group number of 3.5 to 4, The hydroxyl value is 30 to 45 mg KOH / g and the content of ethylene oxide is 10 to 30% by weight.
If the hydroxyl value is 25 to 50 mgKOH / g and the ethylene oxide content is in the range of 5 to 40% by weight, a flexible urethane foam having good moldability can be obtained.
The hydroxyl value and ethylene oxide content are measured by the methods described in the examples.

The polyfunctional polyether polyol can be obtained by a conventionally known method such as adding ethylene oxide and propylene oxide to an organic compound having at least three active hydrogens.
Examples of the organic compound having at least three active hydrogens include glycerin, trimethylolpropane, 1,2,6-hexatriol, pentaerythritol, dipentaerythritol, tetramethylolcyclohexane, methyl glucoside, 2,2,6,6. -Examples include polyhydric alcohols such as tetrakis (hydroxylmethyl) cyclohexanol, and amines such as triethanolamine, ethylenediamine, tolylenediamine, diphenylmethanediamine, and diethylenetriamine. These organic compounds may be used alone or as a mixture.

  The addition form of the organic compound having at least three active hydrogens and ethylene oxide and propylene oxide may be random addition, block addition, or combined addition thereof.

  As the polyfunctional polyether polyol, for example, a tetrafunctional polyether polyol obtained by adding ethylene oxide and propylene oxide to a tetrahydric alcohol such as pentaerythritol and dipentaerythritol is preferably used.

Examples of the aminoplast flame retardant polymer graft polyol include, for example, a melamine dispersed polymer graft polyol, or a fine particle dispersed polyol containing an aminoplast resin dispersion mainly using a urea compound, a melamine compound, a guanamine compound, or a guanidine compound. Etc.
The content of the aminoplast flame-retardant polymer graft polyol in the polyol component is 20 to 80 parts by weight, preferably 40 to 60 parts by weight, in 100 parts by weight of the polyol component.
If the content of the aminoplast flame retardant polymer graft polyol is less than 20 parts by weight, flame retardancy may not be obtained.
Further, when the content of the aminoplast flame retardant polymer graft polyol exceeds 80 parts by weight, the permanent set may be remarkably deteriorated.

  As a method for producing the aminoplast flame retardant polymer graft polyol, the following methods are known. For example, a method of precipitating fine particles by condensing a substance capable of forming an aminoplast resin in a polyol (Japanese Patent Publication No. 57-14708), or an aminoplast resin can be formed in a dispersion medium other than a polyol. There is a method in which fine particles are precipitated by condensing substances and then the dispersion medium is converted into a polyol (Japanese Patent Laid-Open No. 2-91116).

Examples of the polyisocyanate component include isocyanate compounds such as toluene diisocyanate, diphenyl diisocyanate, polymethylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, naphthalene diisocyanate, xylylene diisocyanate, tolylene diisocyanate, and triphenylmethane triisocyanate. be able to.
Further, as a modified product of the isocyanate compound, a prepolymer modified product modified with a polyhydric alcohol such as trimethylolpropane, a dimerized modified product, a trimerized modified product, a urea modified product, a carbodiimide modified product, or the like is used. Also good. Two or more kinds of these isocyanate compounds can be used in combination.

The compounding quantity of the said polyisocyanate component is 60-120 by an isocyanate index, Preferably it is 70-110.
The isocyanate index is the theoretical isocyanate amount calculated from the isocyanate group / active hydrogen compound used.

The non-halogen flame retardant contains at least an organic phosphate ester flame retardant and a metal hydroxide.
Examples of the organic phosphate ester flame retardant include triisobutyl phosphate, trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylenyl phosphate, tetraethylmethylene phosphate, and the like. Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and the like.
Further, the non-halogenated flame retardant may contain, for example, melamine resin, clay, antimony trioxide, zinc white, calcium carbonate and the like.
The non-halogenated flame retardant preferably contains at least triisobutyl phosphate and a metal hydroxide.
The triisobutyl phosphate is a liquid at room temperature, is less likely to increase in viscosity and has better dispersibility than other solid flame retardants, and does not settle when mixed with other raw materials.

The amount of the organic phosphate ester is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the polyol component.
When the compounding amount of the organic phosphate is less than 5 parts by weight with respect to 100 parts by weight of the polyol component, there is a possibility that the improvement of flame retardancy may not be sufficient.
Moreover, when it exceeds 30 weight part, there exists a possibility that foam physical properties, such as compression residual distortion, may deteriorate remarkably.
The compounding quantity of the said metal hydroxide is 5-30 weight part with respect to 100 weight part of said polyol components, Preferably it is 10-25 weight part.
In addition, the compounding quantity of non-halogen-type flame retardants other than an organic phosphate ester type flame retardant or a metal hydroxide can be suitably adjusted unless the property of the flexible urethane foam obtained is impaired.

As said foaming agent, water and a hydrogen atom containing halogen hydrocarbon, a methylene chloride, a low boiling point hydrocarbon, and liquefied carbon dioxide can be used individually or in combination.
Examples of the hydrogen atom-containing halogen hydrocarbon include HFC (hydrofluorocarbons) such as HFC-134a, HFC-152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc, and the like.
Moreover, as a low boiling point hydrocarbon, it is a hydrocarbon with a boiling point of -5-70 degreeC normally, For example, a butane, pentane, cyclopentane, and mixtures thereof are mentioned.
The blending amount of the foaming agent is 4 to 6 parts by weight, preferably 4.8 to 5.5 parts by weight, based on 100 parts by weight of the polyol component.
If the amount of the foaming agent is within the above range, the foam physical properties such as compression residual strain will be good. Incidentally, water is preferably used as the foaming agent.

Examples of the foam stabilizer include silicon-based foam stabilizers such as polyalkylsiloxane and polyalkylsiloxane-polyoxyalkylene block copolymer.
The blending amount of the foam stabilizer may be 0.1 to 3 parts by weight with respect to 100 parts by weight of the polyol component. The foam stabilizer is used to control the cell structure of urethane foam.

  Moreover, in this invention, additives, such as a crosslinking agent, a filler, a coloring agent, antioxidant, and a ultraviolet absorber, can also be used together as needed.

Next, the manufacturing method of the flexible urethane foam of this invention is demonstrated.
The flexible urethane foam of the present invention comprises the polyol component, the polyisocyanate component, the foam stabilizer and the foaming agent in the presence of the non-halogen flame retardant, a one-shot method, a quasi-prepolymer method, a prepolymer method, etc. It manufactures using the well-known method of these.

  When the polyol component and the polyisocyanate component are reacted, an amine catalyst or an organometallic compound catalyst is usually used.

Examples of the amine catalyst include triethylenediamine and bis [(2-dimethylamino) ethyl] ether. A reactive amine catalyst obtained by hydroxylating or aminating a part of the amine catalyst structure with an isocyanate can also be used.
Examples of the reactive amine catalyst include N, N-dimethylethanolamine: HOCH ₂ CH ₂ N (CH ₃ ) ₂ , N, N-dimethylethanolamine diethylene oxide adduct: H (OCH ₂ CH ₂ ) ₃ N ( CH _{3) 2,} trimethyl aminoethyl ethanol _{amine: HOCH 2 CH 2 N (CH} 3) CH 2 CH 2 N (CH 3) 2 and the like.
In addition, the usage-amount of this amine catalyst can be adjusted suitably.

  Examples of the organometallic compound-based catalyst include an organic tin compound, an organic bismuth compound, an organic lead compound, and an organic zinc compound. Specifically, for example, di-n-butyltin oxide, di-n-butyltin dilaurate, di-n-butyltin, di-n-butyltin diacetate, di-n-octyltin oxide, di-n-octyltin dilaurate , Monobutyltin trichloride, di-n-butyltin dialkyl mercaptan, di-n-octyltin dialkyl mercaptan, and the like. The amount of the organometallic compound catalyst used can be adjusted as appropriate.

The flexible urethane foam obtained by the production method of the present invention satisfies the following physical properties.
As the physical properties, the compression residual strain is less than 10%. If the compression residual strain exceeds 10%, the reliability in long-term use with compression may be significantly deteriorated.
The compressive residual strain is measured by the method described in the examples.

  The use of the flexible urethane foam obtained by the production method of the present invention is not particularly limited, but it can be particularly suitably used for electrical appliances that require flame retardancy, for example, high flame retardancy. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to this.

(Measurement method of hydroxyl value)
It measured based on JISK1557-1970.

(Density measurement method)
It measured based on JISK7222.

(Measurement method of compression residual strain)
The compressive residual strain was measured according to JIS K 6400-4 (2004 edition).

(Measurement method of 25% ID hardness)
In accordance with JIS K 6400-2, 5581 type manufactured by Instron Japan Company Limited was used.

(Combustion test (UL94) test method)
The combustion test was measured according to the evaluation method of the American Electrical Materials Combustion Test UL94.

(Synthesis of polyether polyol A)
A 50% aqueous solution of KOH containing 0.3 parts by weight of KOH is added to 100 parts by weight of pentaerythritol, dehydrated at 120 ° C. to convert the hydroxyl group of pentaerythritol to potassium alcoholate, and then 4020 parts by weight of propylene oxide. Was fed into the reactor to carry out an addition reaction, and then 1030 parts by weight of ethylene oxide was fed into the reactor to carry out the addition reaction to obtain polyol A.
Polyether polyol A had a hydroxyl value of 32 mgKOH / g and an ethylene oxide content of 20% by weight.

(Synthesis of polyether polyol B)
The reaction was performed in the same manner as in the synthesis of the polyol A using 100 parts by weight of pentaerythritol, 3690 parts by weight of propylene oxide and 560 parts by weight of ethylene oxide.
Polyether polyol B had a hydroxyl value of 44 mgKOH / g and an ethylene oxide content of 15% by weight.

(Create foam)
Polyurethane foam was foamed using the raw materials in parts by weight shown in Example 1 to Comparative Example 4 in Table 1 under the foaming conditions shown below, and allowed to stand at 20 ° C. for 1 day. After that, the foam physical properties (density, 25% I , LD hardness, compression residual strain) and flammability (UL94HF-1) were measured.
As foaming conditions, hand mixing is used as the mixing method, the raw material temperature is adjusted to 22 ± 1 ° C, the mold temperature is 55 ° C, the mold used is 325 × width 155 × height 50 mm, and the curing conditions Foaming was performed at 55 ° C. for 5 minutes.
The results are shown in Table 1.

＊１）ポリマーポリオールＡ：メラミン分散ポリマーグラフトポリオール、水酸基価２５ｍｇＫＯＨ／ｇ。
＊２）ポリエーテルポリオールＡ：ペンタエリスリトールにプロピレンオキシドを付加させ、次いでエチレンオキシドを付加させた水酸基価３２ｍｇＫＯＨ／ｇのポリエーテルポリオール（エチレンオキサイド含有量２０重量％）。
＊３）ポリエーテルポリオールＢ：ペンタエリスリトールにプロピレンオキシドを付加させ、次いでエチレンオキシドを付加させた水酸基価４４ｍｇＫＯＨ／ｇのポリエーテルポリオール（エチレンオキサイド含有量１５重量％）。
＊４）イソシアネート：ポリメリックＭＤＩ変性物（ＮＣＯ含量２８．８％）尚、イソシアネートインデックスは９５にした。
＊５）難燃剤Ａ：トリイソブチルホスフェート
＊６）難燃剤Ｂ：水酸化アルミニウム。ハイジライトＨ−３２（昭和電工製）
＊７）発泡剤：蒸留水。
＊８）整泡剤：シリコーン系界面活性剤Ｌ−５３０９（東レダウコーニング社製）
＊９）アミン系触媒：トリエチレンジアミン。
＊１０）アミン系触媒：ビス（ジメチルアミノエチル）エーテル。

* 1) Polymer polyol A: Melamine-dispersed polymer graft polyol, hydroxyl value 25 mgKOH / g.
* 2) Polyether polyol A: Polyether polyol having a hydroxyl value of 32 mgKOH / g obtained by adding propylene oxide to pentaerythritol and then adding ethylene oxide (ethylene oxide content 20% by weight).
* 3) Polyether polyol B: Polyether polyol having a hydroxyl value of 44 mgKOH / g obtained by adding propylene oxide to pentaerythritol and then adding ethylene oxide (ethylene oxide content 15% by weight).
* 4) Isocyanate: Polymeric MDI modified product (NCO content 28.8%) The isocyanate index was 95.
* 5) Flame retardant A: Triisobutyl phosphate * 6) Flame retardant B: Aluminum hydroxide. Heidilite H-32 (made by Showa Denko)
* 7) Foaming agent: distilled water.
* 8) Foam stabilizer: silicone surfactant L-5309 (manufactured by Toray Dow Corning)
* 9) Amine-based catalyst: triethylenediamine.
* 10) Amine-based catalyst: bis (dimethylaminoethyl) ether.

  In Examples 1 to 5, it was possible to prevent molding defects and deterioration in compression / restoration properties.

Claims (4)

In the method for producing a flexible urethane foam in which a polyol component, a polyisocyanate component, a foam stabilizer and a foaming agent are reacted in the presence of a non-halogen flame retardant,
The polyol component contains a polyfunctional polyether polyol obtained by adding ethylene oxide and propylene oxide to an organic compound having at least three active hydrogens and an aminoplast-based flame retardant polymer graft polyol,
A method for producing a flexible urethane foam, comprising at least an organophosphate flame retardant and a metal hydroxide as the non-halogen flame retardant.   The method for producing a flexible urethane foam according to claim 1, wherein 20 to 80 parts by weight of the polyfunctional polyether polyol is contained in 100 parts by weight of the polyol component.   The polyfunctional polyether polyol has an average functional group number of 3 to 4, a hydroxyl value of 20 to 50 mgKOH / g, and an ethylene oxide content of 5 to 40% by weight. Method for producing flexible polyurethane foam. The compounding amount of the organic phosphate ester flame retardant is 5 to 30 parts by weight with respect to 100 parts by weight of the polyol component, and the compounding amount of the metal hydroxide is based on 100 parts by weight of the polyol component. It is 5-30 weight part, The manufacturing method of the flexible urethane foam as described in any one of Claims 1-3 characterized by the above-mentioned.