JP2017200993A - Method for producing flexible urethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a flexible urethane foam which can obtain a molded product having a wide and hard width with one polyol formulation and one isocyanate, and has good formability.SOLUTION: There is provided a method for producing a flexible urethane foam by reacting an active hydrogen component (A) and organic isocyanate (B) in the presence of a foaming agent (C), a catalyst (D) and a foam adjusting agent (E), where the active hydrogen component (A) contains a specific amount of polyol having a specific composition, and satisfies the following (1) to (3) conditions: (1) a gel time (t1) of free foaming is more than 12 seconds and 30 seconds or less; (2) the maximum arrival time (rise time: t2) of rise height of free foaming is more than 18 seconds and 40 seconds or less; and (3) (t2)-(t1) is 6 seconds or more and 10 seconds or less.SELECTED DRAWING: None

Description

   The present invention relates to a method for producing a flexible urethane foam, and more particularly to a method for producing a flexible urethane foam suitable for molding.

   Conventionally, as a method for producing a urethane foam, it is known to produce a urethane foam by reacting a polyether polyol and an organic polyisocyanate in the presence of a foaming agent, a catalyst, a foam stabilizer, and the like (for example, Patent Document 1). ).

JP 2003-313262 A

   Conventionally, in a flexible urethane foam molded product, when trying to control the hardness with one kind of polyol formulation and one kind of isocyanate in order to unify raw materials, it is controlled by changing the isocyanate index. When the hardness is lowered, the isocyanate index is lowered, and when the hardness is raised, the isocyanate index is raised to control, but when the isocyanate index is lowered, the foaming property is lowered and air retention failure occurs or the molded product shrinks. Or On the other hand, if it is raised too much, the molded product will be deformed at the time of demolding due to poor curing. Therefore, it is difficult to obtain a molded product having a wide hardness width with one kind of polyol formulation and one kind of isocyanate.

   As a result of earnestly examining the method for solving the above problems, the present inventor uses a polyol having a specific composition, and changes the isocyanate index in order to keep the reactivity between the polyol and the isocyanate within a certain range. The present inventors have found that a flexible urethane foam having a wide hardness width, a good mold release property and liquid flowability, and a good appearance of the molded product can be obtained, and has reached the present invention.

That is, the present invention produces a flexible urethane foam by reacting an active hydrogen component (A) and an organic isocyanate (B) in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E). The active hydrogen component (A) contains the following active hydrogen components (A1) and (A2), and the content in (A) is 50 (A1) based on the weight of (A). It is a manufacturing method of the flexible urethane foam which is -99 weight%, (A2) is 1-50 weight%, and satisfy | fills the conditions of following (1)-(3).
(A1) a polyether polyol having a number average hydroxyl number of 3 to 10, a hydroxyl value of 20 to 50 (mgKOH / g), and a content of terminal ethylene oxide units of 12% by weight or more;
(A2) a polymer polyol obtained by polymerizing the vinyl monomer (b) in the presence of a radical polymerization initiator in (A1);
(1) Free foaming gel time (t1) is more than 12 seconds and not more than 30 seconds;
(2) Rise height maximum arrival time (rise time: t2) of free foaming is more than 18 seconds and not more than 40 seconds;
(3) (t2)-(t1) is 6 seconds or more and 10 seconds or less;

   In the method for producing a flexible urethane foam of the present invention, even if the isocyanate index is greatly changed, the appearance of defects such as air retention and deformation after demolding does not occur, and the moldability is stable and wide. A good flexible urethane foam can be obtained.

In the method for producing a flexible urethane foam of the present invention, the active hydrogen component (A) contains the following active hydrogen components (A1) and (A2), and (A1) and (A2) in the active hydrogen component (A) The contents are 50 to 99% by weight and (A2) 1 to 50% by weight, respectively, based on the weight of (A).
(A1) a polyether polyol having a number average hydroxyl number of 3 to 10, a hydroxyl value of 20 to 50 (mgKOH / g), and a content of terminal ethylene oxide units of 12% by weight or more;
(A2) a polymer polyol obtained by polymerizing the vinyl monomer (b) in the presence of a radical polymerization initiator in (A1);

Examples of the polyether polyol (A1) include alkylene oxide adducts of active hydrogen compounds such as polyhydric alcohols, amines and ammonia.
As polyhydric alcohols, dihydric alcohols (ethylene glycol, propylene glycol, 1,6-hexanediol, etc.); trihydric alcohols (glycerin, trimethylolpropane, etc.); tetrahydric alcohols (pentaerythritol, methylglucoside, etc.); 5 Examples include monohydric alcohols (2, 2, 6, 6, -tetrakis (hydroxymethyl) cyclohexanol and the like); hexavalent alcohols (such as sorbitol); and octavalent alcohols (such as sucrose).
Examples of amines include monovalent amines (dimethylamine, diethylamine, etc.); divalent amines (methylamine, ethylamine, aniline, etc.); trivalent amines (monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, etc.); (Ethylenediamine, hexamethylenediamine, etc.); pentavalent amine (diethylenetriamine, etc.) and the like.
Examples of the alkylene oxide include ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,4- or 2,3-butylene oxide, and combinations of two or more thereof. Among these, preferred are PO and / or EO, and the addition format in the case of combined use may be either block or random.
(A1) is preferably a block co-adduct of polyhydric alcohol PO and EO.

The (A1) has a number average hydroxyl number of 3 to 10, preferably 4 to 8.
In the present invention, the number of hydroxyl groups of the polyol in the case of an alkylene oxide adduct of an active hydrogen compound is regarded as the number of functional groups of the active hydrogen compound as a starting material as the number of hydroxyl groups of the polyol.
The hydroxyl value (mgKOH / g) of (A1) is 20 to 50, preferably 23 to 40, more preferably 25 to 30.
The content of terminal ethylene oxide units (hereinafter referred to as EO units) is 12% by weight or more, preferably 13 to 25% by weight.
When the number of hydroxyl groups in (A1) is 3 or more, poor curing is unlikely to occur and the hardness is difficult to decrease. If the hydroxyl value of (A1) is 50 or less, the foam is not too hard, and if it is 20 or more, the foam is not too soft, and if the content of the terminal EO unit is 12% by weight or more, poor curing occurs. It becomes difficult to get up.
The hydroxyl value is determined according to JIS K1557-1.

   The method for producing the polyether polyol (A1) is not particularly limited, and examples thereof include a method of adding an alkylene oxide to a compound having active hydrogen such as a polyhydric alcohol under an alkali catalyst. Examples include addition polymerization at a temperature of 105 to 130 ° C. and 0.5 MPa or less.

The polymer polyol (A2) in the present invention can be produced by polymerizing the vinyl monomer (b) in the polyether polyol (A1) by a known method. For example, in the polyether polyol (A1), a vinyl monomer (b) is polymerized and stably dispersed in the presence of a radical polymerization initiator. Specific examples of the polymerization method include those described in US Pat. No. 3,383,351, Japanese Examined Patent Publication No. 39-25737, and the like.
The preferred polyether polyol (A1) as the raw material for the polymer polyol (A2) is the same as the preferred polyether polyol (A1).

   As the radical polymerization initiator, those which generate free radicals and initiate polymerization can be used. 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) Azo compounds such as 2,2′-azobis (2-methylbutyronitrile); organic peroxides such as dibenzoyl peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide and persuccinic acid; Examples thereof include inorganic peroxides such as salts and perborate. In addition, these can use 2 or more types together.

Examples of the vinyl monomer (b) include aromatic hydrocarbon monomers (b1), unsaturated nitriles (b2), (meth) acrylic acid esters (b3), other vinyl monomers (b4), and these The mixture of 2 or more types of these is mentioned.
Examples of (b1) include acrylonitrile and methacrylonitrile.
Examples of (b2) include styrene, α-methylstyrene, hydroxystyrene, chlorostyrene and the like.
As (b3), methyl (meth) acrylate, butyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate ( (Meth) acrylic acid alkyl esters (alkyl group having 1 to 24 carbon atoms); hydroxypolyoxyalkylene mono (meth) acrylates (for example, alkylene group having 2 to 4 carbon atoms, polyoxyalkylene chain number average molecular weight 200) ~ 1000).

   Other vinyl monomers (b4) include vinyl group-containing carboxylic acids and derivatives thereof (such as (meth) acrylic acid and (meth) acrylamide), aliphatic or alicyclic hydrocarbon monomers [ethylene, propylene, Norbornene, etc.), fluorine-containing vinyl monomers (perfluorooctylethyl methacrylate, perfluorooctylethyl acrylate, etc.), nitrogen-containing vinyl monomers other than the above (diaminoethyl methacrylate, morpholinoethyl methacrylate, etc.) and vinyl-modified silicon, etc. Can be mentioned.

Among these, (b1) and (b2) are preferable, and acrylonitrile and / or styrene are more preferable.
These weight ratios can be changed according to the required physical properties of the urethane foam and are not particularly limited, but an example is as follows.
(B1): preferably 0 to 100% by weight, more preferably 0 to 80% by weight
(B2): Preferably 0 to 95% by weight, more preferably 20 to 100% by weight
(B3): Preferably 0 to 50% by weight, more preferably 0 to 20% by weight
(B4): Preferably 0 to 10% by weight, more preferably 0 to 5% by weight
In addition, a polyfunctional (preferably 2 to 8 functional) vinyl group-containing monomer [divinylbenzene, ethylene di (meth) acrylate, etc.] is used as at least a part (preferably 0.05 to 1% by weight) of (b). As a result, the strength of the polymer can be further improved.
The content of the polymer (b) in the polymer polyol (A12) is preferably 1 to 50% by weight, more preferably 5 to 45% by weight.

The active hydrogen component (A) may contain polyether alcohol (A3). (A3) has a number average hydroxyl number of 1 to 2.9, preferably 1.5 to 2.5. The content of (A3) is preferably 30% by weight or less based on the weight of (A).
(A3) is preferably a block of PO and / or EO of alcohol or a random co-adduct.
As said alcohol, monohydric alcohol (methanol, ethanol, 1-propanol etc.) can also be used other than the said polyhydric alcohol.
The hydroxyl value (mgKOH / g) of (A3) is 20-50, preferably 23-40, more preferably 25-30.
When the number of hydroxyl groups in (A3) is 1 or more, poor curing is unlikely to occur and hardness is unlikely to decrease.
Further, when the hydroxyl value of (A3) is 50 or less, the foam is not too hard, and when it is 20 or less, the foam is not too soft.

   The active hydrogen component (A3) preferably has a total (terminal and internal) content of EO units of 10% by weight or more and a content of terminal EO units of 5% by weight or more, more preferably EO units. The total content of EO units is 15 to 30% by weight, the content of terminal EO units is 8 to 20% by weight, and the total content of EO units is particularly preferably 20 to 25% by weight. The unit content is 10 to 15% by weight.

   In the active hydrogen component (A), in addition to the active hydrogen components (A1) to (A3), other polyols or active hydrogen components (A4) may be used in combination, and other than (A1) to (A3) Examples include polyether polyols, polyester polyols, modified polyols or monools, polyhydric alcohols, amines, and mixtures thereof.

   Examples of the polyester polyol include the above-mentioned polyhydric alcohols (in particular, dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol; Polyether polyols; or a mixture thereof with a trihydric or higher polyhydric alcohol such as glycerin or trimethylolpropane) and the polycarboxylic acid or anhydride thereof, lower alkyl (carbon number of alkyl group: 1 to 4). ) Ester-forming derivatives such as esters (adipic acid, sebacic acid, maleic anhydride, phthalic anhydride, dimethyl terephthalate, etc.), or condensation reaction products of the carboxylic anhydride and AO; alkyleonoxide (EO) , PO, etc.) addition reaction product; polylacto Polyols, those obtained by ring-opening polymerization of lactones (e.g., ε-caprolactone) using the above polyols as initiators; polycarbonate polyols, reaction products of the above polyols with carbonic acid diesters of lower alcohols (such as methanol), and the like. .

As modified polyols or monools, polymer polyols other than those using polyether polyols; polydiene polyols such as polybutadiene polyols and hydrogenated products thereof; acrylic polyols, JP-A 58-57413 and JP-A 58 Hydroxyl group-containing vinyl polymers described in JP-57414; natural oil-based polyols such as castor oil; modified products of natural oil-based polyols; terminal radical polymerizable functional group-containing activities described in International Publication WO98 / 44016 A hydrogen compound; and the like.
Examples of the polyhydric alcohol and amine include those described above.

The content of (A1) and (A2) in the active hydrogen component (A) is 50 to 99% by weight of (A1) and (A2) based on the weight of (A) from the viewpoint of mechanical properties of the foam. 1 to 50% by weight, preferably (A1) is 50 to 90% by weight, (A2) is 10 to 45% by weight, more preferably (A1) is 55 to 75% by weight, and (A2) is 20%. -40% by weight.
Further, (A) preferably contains (A3) from the viewpoint of mechanical properties of the foam. When (A3) is included, the content of (A1), (A2) and (A3) is based on the weight of (A), (A1) is 50 wt% or more and less than 99 wt%, (A2) is 1 wt% or more Less than 50% by weight, (A3) is preferably 30% by weight or less, more preferably (A1) is 55 to 75% by weight, (A2) is 20 to 40% by weight, and (A3) is 1 to 20% by weight.

   In the present invention, the polymer content of the vinyl monomer (b) in the active hydrogen component (A) is preferably 0.5 to 35% by weight, more preferably 2 to 30% by weight. When it is 35% by weight or less, appearance defects such as cell roughness are less likely to occur in the foam.

As organic isocyanate (B) used for the manufacturing method of the flexible urethane foam of this invention, the well-known thing used for manufacture of urethane foam, for example, the fragrance of 6-20 carbon atoms (except the carbon number in NCO group) Polyisocyanate [2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′- or 4,4′-diphenylmethane diisocyanate (MDI), crude MDI, polyaryl polyisocyanate (PAPI) Etc.]; linear or branched aliphatic isocyanates having 2 to 18 carbon atoms (hexamethylene diisocyanate, lysine diisocyanate, etc.); alicyclic polyisocyanates having 4 to 15 carbon atoms (isophorone diisocyanate, dicyclohexyl diisocyanate, etc.); Isocyanate modified Tan group, carbodiimide group, allophanate group, urea group, uretdione group, biuret group, uretonimine groups, isocyanurate groups, oxazolidone group-containing modified products, etc.); and the combination and the like of two or more of these.
Among these (B), one or more selected from the group consisting of 2,4′-diphenylmethane diisocyanate, 4-4′-diphenylmethane diisocyanate, and polymethylene polyphenylene polyisocyanate is preferable.

   As the foaming agent (C), water, hydrogen atom-containing halogenated hydrocarbon, low boiling point hydrocarbon, liquefied carbon dioxide gas, or the like is used, and two or more kinds may be used in combination. Among these, water alone is particularly preferable from the viewpoint of environmental pollution.

   In the case of water, the amount of the blowing agent (C) based on the weight of the active hydrogen component (A) is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, particularly preferably 3 to 5% by weight. %. When the water content in (C) is 0.1% by weight or more, the liquid flowability of the foam is good, and cell roughening due to insufficient filling is unlikely to occur.

   As the catalyst (D) used in the present invention, any catalyst that promotes all urethanization reactions conventionally used in the art can be used, and triethylenediamine, triethylamine, triethanolamine, bis (N, N-dimethylamino). Ethyl) ether, N, N-dimethylaminopropyldipropanolamine, N, N, N ′, N′-tetramethylhexamethylenediamine and 1,8-diazabicyclo (5,4,0) undecene and / or a salt thereof And amine metal catalysts, organometallic compounds such as dibutyltin laurate, and carboxylic acid metal salts such as potassium acetate, potassium octylate and stannous octoate. By using the above catalyst, the condensation reaction in forming the polyurethane can be controlled to an appropriate state.

   The amount of the catalyst (D) used is preferably 0.1 to 15% by weight, more preferably 0.3 to 5% by weight, based on the weight of the active hydrogen component (A), from the viewpoint of moldability of the foam. Particularly preferred is 0.5 to 3% by weight.

   As the foam stabilizer (E) used in the present invention, all known foam stabilizers used in the production of urethane foam can be used. Polyether-modified dimethylsiloxane foam stabilizer [[Toray Dow Corning " SRX-274C "," SF-2962 ", etc.]," L-5309 "manufactured by Momentive Performance Materials, and the like. The amount of the foam stabilizer used is preferably 0.1 to 10.0% by weight based on the weight of the polyether polyol (A), more preferably from the viewpoint of moldability of the urethane foam and discoloration of the foam. It is 2 to 5.0% by weight, particularly preferably 0.3 to 3.0% by weight.

   In the present invention, an anti-aging agent such as a flame retardant (F) (such as phosphate ester), an antioxidant (such as hindered phenol and hindered amine) and an ultraviolet absorber (such as triazole and benzophenone); And fillers such as inorganic fibers (glass fibers and carbon fibers), whiskers (potassium titanate whiskers, etc.); adhesives (modified polycaprolactone polyols, etc.); plasticizers (phthalates, etc.); Conventionally known additives and auxiliaries such as colorants (dyes and pigments); antibacterial agents; antifungal agents; and the like can be used.

   The isocyanate index (index) [equivalent ratio of (NCO group / active hydrogen atom-containing group) × 100] in the method for producing a flexible urethane foam of the present invention is 5 to 300 from the viewpoint of the curing property of the foam and the moldability of the foam. Is more preferable, 10 to 200 is more preferable, and 30 to 150 is particularly preferable.

   A specific example of the method for producing the flexible urethane foam of the present invention is as follows. First, the active hydrogen component (A), the foaming agent (C), the catalyst (D) and the foam stabilizer (E), and if necessary, other additives and auxiliaries are mixed in a predetermined amount in a 2 L plastic container to obtain a polyol mixture. Prepare and adjust temperature to 25 ± 5 ° C. Next, a predetermined amount of organic isocyanate (B) whose temperature is adjusted to 25 ± 5 ° C. is added, and stirred and mixed with a stirrer (Homodisper: manufactured by Primix Co., Ltd.) at 8000 rpm × 2 seconds, foamed and cured to obtain a flexible urethane foam. . Additives, auxiliaries and the like can also be used by mixing with organic isocyanate (B).

In the method for producing a flexible urethane foam of the present invention, the raw material reaction conditions and the like are adjusted so as to satisfy the following (1) to (3).
(1) Free foaming gel time (t1) is more than 12 seconds and not more than 30 seconds;
(2) Rise height maximum arrival time (rise time: t2) of free foaming is more than 18 seconds and not more than 40 seconds;
(3) (t2)-(t1) is 6 seconds or more and 10 seconds or less;

In the present invention, cream time, gel time, rise height, and rise time mean the following.
Cream time is when the active hydrogen component (A) and the organic isocyanate (B) are mixed together with the foaming agent (C), the catalyst (D) and the foam stabilizer (E) for free foaming. It means the time until the liquid level starts to rise.

The gel time (t1) is a mixture of the active hydrogen component (A) and the organic isocyanate (B) when the foaming agent (C), the catalyst (D) and the foam stabilizer (E) are all mixed and free-foamed. It means the time from the start to the time when thickening occurs and the gel strength starts to appear (resinization). The gel time in the production method of the present invention is more than 12 seconds and not more than 30 seconds, preferably not less than 13 seconds and not more than 25 seconds, particularly Preferably it is 13 seconds or more and 20 seconds or less. If the gel time is 12 seconds or less, insufficient liquid flow is likely to occur, and if it exceeds 30 seconds, poor curing tends to occur.
Examples of the technique for setting the gel time to more than 12 seconds include increasing the ratio of the primary hydroxyl group of the active hydrogen component (A) and increasing the amount of the catalyst (D) used. Examples thereof include reducing the ratio of primary hydroxyl groups of the active hydrogen component (A) and reducing the amount of catalyst (D) used.

The rise time (t2) in the present invention means free foaming by mixing the active hydrogen component (A) and the organic isocyanate (B) with the foaming agent (C), the catalyst (D) and the foam stabilizer (E). Means the time from the start of mixing until the height of the raised foam is maximized.
The rise time (t2) in the production method of the present invention is preferably more than 18 seconds and 40 seconds or less, more preferably 19 seconds to 35 seconds, and particularly preferably 19 seconds to 30 seconds. If the rise time is 18 seconds or less, liquid flowability is likely to be insufficient, and if it exceeds 40 seconds, poor curing tends to occur.
Examples of the method for setting the rise time (t2) to more than 18 seconds include increasing the ratio of the primary hydroxyl group of the active hydrogen component (A) and increasing the amount of the catalyst (D) used. Examples of the technique include reducing the ratio of the primary hydroxyl group of the active hydrogen component (A) and reducing the amount of the catalyst (D) used.

Moreover, (t2)-(t1) is 6 seconds or more and 10 seconds or less, preferably 6 seconds or more and 9 seconds or less, and more preferably 7 seconds or more and 8 seconds or less. When (t2)-(t1) exceeds 10 seconds, the liquid flowability is likely to be insufficient, and an air accumulation defect or the like may occur.
Examples of the method of setting (t2)-(t1) to 6 seconds or more include increasing the amount of water or catalyst (D) used.

   In the production method of the present invention, in the case of a molded foam, the time from when the active hydrogen component (A) and the organic isocyanate (B) start to react (start mixing of raw materials containing them) until the molded product is taken out Is preferably 120 seconds or less. According to the manufacturing method of the present invention, there is no possibility of appearance defects occurring in the molded product even if the mold is removed in a short time.

If the flexible urethane foam molded product obtained by the method for producing a flexible urethane foam of the present invention has an air permeability of less than 0.10 ft ³ / min, defects such as shrinkage of the molded product may occur.

The air permeability indicates a numerical value measured by a Dow type air flow meter (ASTM-3574), the unit is expressed in ft ³ / min, and preferably 0.10 ft ³ / min or more. As a method for setting the air permeability to 0.10 ft ³ / min or more, for example, the amount of active hydrogen component water or a catalyst is decreased.

The method of manufacturing a flexible polyurethane foam of the present invention, the core density of the resulting flexible polyurethane foam molded article is preferably 25~70kg / m ^3, more preferably 28~65kg / m ^3, particularly preferably 30~60kg / m ³ .
The free density in the present invention is measured according to JIS K6400.

   EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by this. In the following, “%” means “% by weight” unless otherwise specified.

[Examples 1-7, Comparative Examples 1-6]
The soft urethane foam raw materials in the examples and comparative examples are as follows.
(1) Polyol (A1-1): PO / EO block adduct of sucrose (hydroxyl value = 28, content of terminal EO unit = 20%).
(2) Polyol (A1-2): PO / EO block adduct of glycerin (hydroxyl value = 34, content of terminal EO unit = 20%).
(3) Polyol (A2-1): Polymer polyol obtained by polymerizing acrylonitrile in a polyol of PO / EO block adduct of glycerin (hydroxyl value = 34, content of terminal EO unit = 20%) ( Polymer content 20%).
(4) Polyol (A2-2): a polymer obtained by polymerizing acrylonitrile and styrene in a PO / EO block adduct of pentaerythritol (hydroxyl value = 28, content of terminal EO unit = 14%) Polyol (polymer content 30%, acrylonitrile / styrene = 67/33 weight ratio).
(5) Polyol (A3): PO / EO / PO / EO block adduct of propylene glycol (hydroxyl value = 28, total content of EO units = 20%, content of terminal EO units = 10%).
(6) Polyol (A4-1): Triethanolamine (7) Polyol (A4-2): PO / EO random adduct of glycerin (hydroxyl value = 24, EO unit content = 72%)
(8) Foaming agent (C-1): Water (9) Catalyst (D-1): Dipropylene glycol solution of triethylenediamine [TEDA-L33 manufactured by Tosoh Corporation]
(10) Catalyst (D-2): 70% dipropylene glycol solution of bis (dimethylaminoethyl) ether [TOYOCAT ET manufactured by Tosoh Corporation]
(11) Catalyst (D-3): Bis (dimethylaminoethyl) ether [DABCO-BL19 manufactured by Airpro]
(12) Catalyst (D-4): Amine-based reactive catalyst [Kao Riser No. manufactured by Kao Corporation. 25]
(13) Catalyst (D-5): Amine-based reactive catalyst [TOYOCAT HX-70 manufactured by Tosoh Corporation]
(14) Foam stabilizer (E-1): “SF-2962” manufactured by Toray Dow Corning Silicone Co., Ltd.
(15) Organic isocyanate (B-1): Crude MDI [Nippon Polyurethane Industry Co., Ltd. MR-200] NCO% = 31
(16) Organic isocyanate (B-2): polyether-modified MDI [manufactured by Nippon Polyurethane Industry Co., Ltd.] NCO% = 28

<Molding conditions>
-Foaming machine: MINI-RIM, L-type head manufactured by Polymer Engineering Co., Ltd.-Discharge pressure: 14-16 MPa
・ Discharge rate: 200 g / sec ・ Liquid temperature: 30-35 ° C.
-Demolding time: 60 seconds Table 1 shows the measurement results of moldability and physical property values of the obtained foams.
In Table 1, the amount of materials used is shown in parts by weight. The amount of organic isocyanate (B) charged is indicated by an index (isocyanate index).

Table 1 shows the measurement results of cream time, gel time (t1), rise time (t2), (t2)-(t1), core density, and air permeability measured by the above-described method in each example and comparative example. .
Table 1 shows the evaluation results of presence / absence of deformation after removal from the mold 60 seconds after the start of mixing (none: ◯, present: ×) and presence of air retention in the foam molded product (none: ◯, present: ×). Show.
Furthermore, Push-Pull hardness was measured. The measurement method is as described below.
Using a Push-Pull hardness tester, the stress was measured when the tip of a 20 mm cylinder was pushed 15 mm vertically into the foam using a spherical jig.

The flexible urethane foam obtained by the production method of the present invention can be suitably used for all uses of flexible urethane foam such as headrests and armrests for automobile interiors.
In particular, it is suitable for a flexible urethane foam in which a headrest or armrest for an automobile interior material is integrally formed with a skin material (such as a thermoplastic resin molded product).

Claims (9)

A method for producing a flexible urethane foam by reacting an active hydrogen component (A) and an organic isocyanate (B) in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E), The active hydrogen component (A) contains the following active hydrogen components (A1) and (A2), and the content in (A) is 50 to 99% by weight of (A1) based on the weight of (A), (A2) is 1 to 50 weight%, and the manufacturing method of the flexible urethane foam which satisfy | fills the conditions of following (1)-(3).
(A1) a polyether polyol having a number average hydroxyl number of 3 to 10, a hydroxyl value of 20 to 50 (mgKOH / g), and a content of terminal ethylene oxide units of 12% by weight or more;
(A2) a polymer polyol obtained by polymerizing the vinyl monomer (b) in the presence of a radical polymerization initiator in (A1);
(1) Free foaming gel time (t1) is more than 12 seconds and not more than 30 seconds;
(2) Rise height maximum arrival time (rise time: t2) of free foaming is more than 18 seconds and not more than 40 seconds;
(3) (t2)-(t1) is 6 seconds or more and 10 seconds or less; A method for producing a flexible urethane foam by reacting an active hydrogen component (A) and an organic isocyanate (B) in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E), The active hydrogen component (A) contains the following active hydrogen components (A1), (A2), and (A3), and the content in (A) is 50% by weight based on the weight of (A) (A1). % To less than 99% by weight, (A2) from 1% to less than 50% by weight, (A3) from 30% by weight or less, and the production of flexible urethane foam that satisfies the following conditions (1) to (3) Method.
(A1) a polyether polyol having a number average hydroxyl number of 3 to 10, a hydroxyl value of 20 to 50 (mgKOH / g), and a content of terminal ethylene oxide units of 12% by weight or more;
(A2) a polymer polyol obtained by polymerizing the vinyl monomer (b) in the presence of a radical polymerization initiator in (A1);
(A3) a polyether alcohol having a number average hydroxyl number of 1 to 2.9 and a hydroxyl value of 20 to 50 (mgKOH / g);
(1) Free foaming gel time (t1) is more than 12 seconds and not more than 30 seconds;
(2) Rise height maximum arrival time (rise time: t2) of free foaming is more than 18 seconds and not more than 40 seconds;
(3) (t2)-(t1) is 6 seconds or more and 10 seconds or less;    The soft urethane according to claim 1 or 2, wherein the organic isocyanate (B) contains one or more selected from the group consisting of 2,4'-diphenylmethane diisocyanate, 4-4'-diphenylmethane diisocyanate, and polymethylene polyphenylene polyisocyanate. Form manufacturing method.    The method for producing a flexible urethane foam according to any one of claims 1 to 3, wherein the foaming agent (C) is water.    The foam obtained is a molded foam, and the time from when the reaction between the active hydrogen component (A) and the organic isocyanate (B) starts to take out the molded foam is 120 seconds or less. The manufacturing method of the flexible urethane foam of Claim 1.    The method for producing a flexible urethane foam according to any one of claims 1 to 5, wherein a shape of the obtained foam is a headrest or an armrest for an automobile interior material and is integrally formed with a skin material. The core density of the foam obtained is 25-70 kg / m < ³ >, The manufacturing method of the flexible urethane foam of any one of Claims 1-6. The method for producing a flexible urethane foam according to any one of claims 1 to 7, wherein the air permeability of the obtained foam is 0.10 ft ³ / min or more. The active hydrogen component (A3) is a polyether alcohol having a total content of ethylene oxide units of 10% by weight or more and a content of terminal ethylene oxide units of 5% by weight or more. The manufacturing method of the flexible urethane foam as described in any one of.