JP2015071754A - Method for manufacturing soft polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing soft polyurethane foam excellent in vibration characteristic and high in durability.SOLUTION: There is provided a method for manufacturing soft polyurethane foam including reacting a polyol component containing following polyol (A1) (A) and an organic polyisocyanate component (B) in a presence of a catalyst, a foaming agent and a foam stabilizer, and a resonance frequency value of a foam sample having 400 mm×400 mm×100 mm dimension of obtained foam is 3.4 Hz or less and a resonance transmission rate is 3.0 or less. Polyol (A1):polyether polyol having a number average functional group number of 3 to 4, percentage of primary hydroxyl group in the all terminal hydroxyl group of 80 mol% or more, a hydroxyl group value (mgKOH/g) of 25 to 40, terminal oxyethylene unit content of 8 to 12 wt.%, monool content of 0.04 meq/g or less and diol content of 8 to 20 wt.%.

Description

  The present invention relates to a method for producing a flexible polyurethane foam. More specifically, the present invention relates to a method for producing a flexible polyurethane foam suitable for uses such as a cushion material for seats installed in a vehicle such as an automobile; It relates to a flexible polyurethane foam.

  A flexible polyurethane foam is generally used for a cushion material for a vehicle seat of an automobile or the like. However, in recent years, in addition to the functions conventionally required as a cushioning material, a seat having good vibration characteristics has been demanded for the purpose of improving riding comfort. In order to improve the ride comfort of the seat, it is necessary to reduce the vibration transmission rate in the vibration region (4 to 10 Hz) that people feel uncomfortable with respect to the vibration transmission characteristics defined in JASCO B-407. For this purpose, it is effective to lower the resonance frequency and lower the vibration transmissibility (resonance magnification) at the resonance frequency. In order to improve vibration characteristics, there is known a method of using a specific polyol having a low degree of unsaturation and blending an organic filler with an inorganic treatment (see Patent Document 1).

JP 2008-127514 A

  However, if it is attempted to reduce the thickness from the viewpoint of weight reduction, there is a problem that the durability is lowered, and it is difficult to achieve both reduction in thickness and vibration absorption characteristics. Therefore, an object of the present invention is to provide a method for producing a flexible polyurethane foam having excellent vibration characteristics and high durability.

As a result of intensive studies to solve these problems, the present inventors have achieved excellent vibration characteristics and satisfactory durability when thinned by a polyurethane foam production method using a polyol having a specific structure. The present inventors have found that a flexible urethane foam can be obtained and have reached the present invention.
That is, the present invention comprises a polyol component (A) containing the following polyol (A1) and an organic polyisocyanate component (B) in the presence of a catalyst (C), a foaming agent (D) and a foam stabilizer (E). A method for producing a flexible polyurethane foam that reacts with the foam polyurethane, wherein the foam sample having a size of 400 mm × 400 mm × 100 mm has a resonance frequency value of 3.4 Hz or less and a resonance transmissibility of 3.0 or less. A foam production method; a flexible polyurethane foam obtained by the production method described above; and a vehicle seat cushion composed of the flexible polyurethane foam.
Polyol (A1): A polyether polyol that satisfies the following (1) to (6).
(1) The number average functional group number is 3-4.
(2) The proportion of primary hydroxyl groups in all terminal hydroxyl groups is 80 mol% or more.
(3) The hydroxyl value (mgKOH / g) is 25-40.
(4) The content of the terminal oxyethylene unit is 8 to 12% by weight based on the weight of (A1).
(5) The monool content is 0.04 meq / g or less.
(6) The diol content is 8 to 20% by weight.

  The flexible polyurethane foam of the present invention obtained by the production method of the present invention has the characteristics of good vibration characteristics and high durability.

  The polyol component (A) used in the present invention contains a polyol (A1) that satisfies the above (1) to (6). The polyol (A1) is a polyether polyol.

  As the polyol (A1), a trivalent or higher (preferably 3 to 4) active hydrogen-containing compound (for example, a polyhydric alcohol, an amine, a polyhydric phenol, and a mixture thereof) is added to an alkylene oxide (hereinafter referred to as “polyoxide”). Abbreviated as AO)).

  Examples of the polyhydric alcohol include trihydric alcohols having 3 to 20 carbon atoms (aliphatic triols such as alkanetriols such as glycerin, trimethylolpropane, trimethylolethane, and hexanetriol); 4 to 8 carbon atoms having 5 to 20 carbon atoms. And higher polyhydric alcohols (aliphatic polyols such as alkane polyols such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin and dipentaerythritol and intramolecular or intermolecular dehydrates of these or alkanetriols; Saccharides such as sugar, glucose, mannose, fructose and methylglucoside and derivatives thereof).

Amines include alkanolamines, polyamines, and monoamines.
Examples of the alkanolamine include mono-, di- and tri-alkanolamines having 2 to 20 carbon atoms (for example, monoethanolamine, diethanolamine, triethanolamine and isopropanolamine).
As a polyamine (the number of primary, secondary amino groups: 2 to 8 or more), as an aliphatic amine, an alkylenediamine having 2 to 6 carbon atoms (for example, ethylenediamine, propylenediamine and hexamethylenediamine), carbon number 4-20 polyalkylene polyamines (dialkylene triamines having 6 to 6 carbon atoms in the alkylene group, hexaalkylene heptamines such as diethylenetriamine and triethylenetetramine) and the like.
Also, aromatic polyamines having 6 to 20 carbon atoms (for example, phenylenediamine, tolylenediamine, xylylenediamine, diethyltoluenediamine, methylenedianiline and diphenyletherdiamine); alicyclic polyamines having 4 to 20 carbon atoms (for example, Isophoronediamine, cyclohexylenediamine, and dicyclohexylmethanediamine); heterocyclic polyamines having 4 to 20 carbon atoms (for example, piperazine and aminoethylpiperazine) and the like.
A monoamine includes ammonia.

Examples of the polyvalent (3 to 8 valent or higher) phenol include monocyclic polyphenols such as pyrogallol and phloroglucin; condensates of phenol and formaldehyde (novolac); for example, polyphenols described in US Pat. No. 3,265,641 Can be mentioned.
Two or more of these active hydrogen-containing compounds may be used in combination. Among these, a trihydric to tetravalent polyhydric alcohol is preferable.

As the AO added to the active hydrogen-containing compound, propylene oxide (hereinafter abbreviated as PO) and ethylene oxide (hereinafter abbreviated as EO) are preferable. AO preferably contains only these, but 10% by weight or less in AO (hereinafter, “%” means “% by weight unless otherwise specified”), and more preferably 5% or less. May be used in combination. Other AOs are preferably those having 4 to 8 carbon atoms, such as 1,2-, 1,3-, 1,4- and 2,3-butylene oxide and styrene oxide. Also good.
As an addition format of AO including PO and EO, a block addition in the order of PO and EO is preferable.

The hydroxyl value (mgKOH / g, the following hydroxyl values are the same) of the polyol (A1) used in the present invention is 25 to 40, preferably 28 to 35, from the viewpoint of vibration characteristics and durability. When the hydroxyl value is less than 25, the durability is lowered, and when it exceeds 40, the resonance frequency is lowered.
In the present invention, the hydroxyl value is measured according to JIS K1557-1.

The content of the terminal oxyethylene unit (hereinafter, oxyethylene unit is referred to as EO unit) of the polyol (A1) is 8 to 12% from the viewpoint of sufficiently curing and reducing closed cells, 8-10%.
The content of the internal EO unit in (A1) is preferably 3% or less, more preferably 0%, from the viewpoint of the compression set rate of the foam. Here, the internal EO unit refers to an EO unit other than the terminal EO unit among the EO units of the entire polyol.

The monool content in the polyol (A1) is 0.04 meq / g or less, preferably 0.03 to 0.01 meq / g, from the viewpoint of tensile strength. The monool content is determined according to JISK-1557.
Monool is generated as a by-product when AO is added to an active hydrogen-containing compound to produce a polyol (A1), and is contained in (A1).

  The diol content in the polyol (A1) is 8 to 20%, preferably 12 to 18%. When the diol content is less than 8%, the elongation decreases, and when it exceeds 20%, the compression residual strain ratio deteriorates.

The diol is generated as a by-product during the production of (A1), when AO is added to the active hydrogen-containing compound, or during the post-treatment step for removing the catalyst after the AO addition, and is contained in (A1). Those may be used as they are, but when the diol content is outside the above range, the amount is adjusted.
When the diol content exceeds the upper limit, the polyol (A1) can be distilled by distillation under reduced pressure to remove the low boiling point diol.
Moreover, when a diol content is less than a minimum, it can adjust by adding diol in a polyol (A1). Examples of the diol to be added include an AO adduct (hydroxyl value: 20 to 400) of a dihydric alcohol having 2 to 20 carbon atoms (ethylene glycol, propylene glycol, 1,4-butanediol, etc.).

In the present invention, the diol content is measured under the following conditions using gel permeation chromatography (GPC).
Device (example): HLC-8120 manufactured by Tosoh Corporation
Column (example): TSK GEL GMH6 2 [Tosoh Corp.]
Measurement temperature: 40 ° C
Sample solution: 0.25% THF (tetrahydrofuran) solution Injection amount: 100 μl
Detection apparatus: Refractive index detector Reference material: Standard polystyrene (TSK standard POLYSTYRENE) 12 points (molecular weight 500 1050 2800 5970 9100 18100 37900 96400 190000 355000 1890000 2890000) manufactured by Tosoh Corporation
Moreover, what melt | dissolved a sample in THF and separated the insoluble content with the glass filter is made into a sample solution.

The number average functional group number per molecule of the polyol (A1) is 3 to 4 and preferably 4 from the viewpoint of the curing rate and compression set rate of the foam. Even if the number of functional groups is 5 or more, the number average functional groups may be 3 to 4 (the same applies to the average functional groups of other polyether polyols). In the present invention, the number of functional groups of the polyether polyol is considered to be the same as the number of functional groups of the active hydrogen-containing compound as a starting material. In the present invention, the average functional group number means the number average functional group number.
In addition, since a polyol (A1) contains the specific amount of diol mainly derived from a by-product, when using (A1) from which a substantial number average functional group number is less than 3, it is contained in this invention.
The ratio of the primary hydroxyl value to the total terminal hydroxyl groups of (A1) is 80 mol% or more, preferably 86 mol% or more, from the viewpoint of the vibration characteristics of the foam.

In the present invention, the proportion of primary hydroxyl groups in all terminal hydroxyl groups (primary hydroxylation rate of terminal hydroxyl groups) is determined by ¹ H-NMR method after pre-treatment of the sample in advance. Details of the ¹ H-NMR method will be specifically described below.
<Sample preparation method>
About 30 mg of a measurement sample is weighed into a sample tube for ¹ H-NMR having a diameter of 5 mm, and about 0.5 ml of deuterated solvent is added and dissolved. Thereafter, about 0.1 ml of trifluoroacetic anhydride is added and the mixture is allowed to stand at 25 ° C. for about 5 minutes to make the polyol a trifluoroacetic acid ester, which is used as a sample for analysis.
Here, the deuterated solvent is deuterated chloroform, deuterated toluene, deuterated dimethyl sulfoxide, deuterated dimethylformamide, or the like, and a solvent that can be dissolved in the sample is appropriately selected.

<NMR measurement>
¹ H-NMR measurement is performed under normal conditions.
<Calculation method of primary OH ratio of terminal hydroxyl group>
The signal derived from the methylene group to which the primary hydroxyl group is bonded is observed at around 4.3 ppm, and the signal derived from the methine group to which the secondary hydroxyl group is bonded is observed at around 5.2 ppm. Is calculated by the following formula (1).
Primary OH conversion rate (%) = [r / (r + 2s)] × 100 (1)
However,
r: integrated value of a signal derived from a methylene group to which a primary hydroxyl group is bonded in the vicinity of 4.3 ppm s: an integrated value of a signal derived from a methine group to which a secondary hydroxyl group is bonded in the vicinity of 5.2 ppm.

  The polyol (A1) is a polyether polyol in which the average addition mole number x of EO per active hydrogen and the primary OH conversion rate y (%) of the terminal hydroxyl group satisfy the relationship of the following formula (2). It is preferable from the viewpoint of reactivity.

y ≧ 42.0x ^0.47 (1-x / 41) (2)
When the relationship between x and y satisfies the above formula (2), both the hydrophobicity and the reactivity are good, and a polyurethane foam having high mechanical properties and excellent durability is obtained.
In general, the higher the amount of EO added, the higher the primary OH conversion rate of the terminal hydroxyl group of the polyether polyol. However, as the amount of EO added increases, the hydrophilicity of the polyether polyol increases, and the moisture resistance of the resulting polyurethane foam deteriorates. Accordingly, a polyether polyol having a relatively small EO addition mole number but a large primary OH conversion ratio is preferred in terms of both the reactivity and hydrophobicity of the polyether polyol. Equation (2) represents the preferred region.

  The primary OH conversion rate of the terminal hydroxyl group is 80% or more using a polyol obtained by PO addition using an acid catalyst (α) described later and then terminal EO addition, and a commonly used alkali catalyst such as potassium hydroxide. A distinction is made from polyols obtained in similar addition formats. That is, while (A1) obtained using (α) satisfies the primary OH conversion rate of 80% or more of the terminal hydroxyl group, a polyol obtained using an alkali catalyst usually does not satisfy.

Examples of a method for obtaining this polyol (A1) include a method of adding AO to the active hydrogen-containing compound in the order of PO and EO in the presence of a specific acid catalyst (α). When an alkali catalyst such as potassium hydroxide usually used for AO addition is used, a polyol having a terminal EO unit content of 8 to 12% and a terminal hydroxyl group primary OH conversion ratio of 80 mol% or more is obtained. It is very difficult.
(Α) is used at the time of PO addition, but it is not always necessary to use it at all stages of PO addition. After adding a part of PO in the presence of other commonly used catalysts described later, only (α) ) May be used to add the remaining PO.
Examples of (α) include those described in JP-A No. 2000-344881. Specifically, boron other than BF ₃ is bonded to a fluorine atom, a (substituted) phenyl group and / or a tertiary alkyl group. Or an aluminum compound such as triphenylborane, diphenyl-t-butylborane, tri (t-butyl) borane, triphenylaluminum, diphenyl-t-butylaluminum, tri (t-butyl) aluminum, tris (pentafluorophenyl) borane Bis (pentafluorophenyl) -t-butylborane, tris (pentafluorophenyl) aluminum and bis (pentafluorophenyl) -t-butylaluminum.
Among these, preferred are triphenylborane, triphenylaluminum, tris (pentafluorophenyl) borane and tris (pentafluorophenyl) aluminum, and more preferred are tris (pentafluorophenyl) borane and tris (pentafluoro). Phenyl) aluminum.
The addition conditions of AO may be the same as the method described in the above publication. For example, based on the weight of the ring-opening polymer to be formed, preferably 0.0001 to 10%, more preferably 0.001 to 1%. The above catalyst is used, and the reaction is preferably performed at 0 to 250 ° C, more preferably 20 to 180 ° C.

By adding EO to the above PO adduct, a polyol having a higher primary OH conversion rate can be obtained. When the catalyst (α) is used, the primary OH conversion ratio of the terminal hydroxyl group of the polyol before EO addition is usually as large as 40 mol% or more (preferably 60 mol% or more, more preferably 70 mol% or more). The primary OH conversion rate of the terminal hydroxyl group can be increased with a small amount of EO used. As the catalyst used for the EO addition, the acid catalyst (α) may be used as it is, or another catalyst that is usually used may be used instead.
Other catalysts include alkali catalysts such as sodium hydroxide, potassium hydroxide, cesium hydroxide, potassium carbonate and triethylenediamine; acid catalysts such as boron trifluoride, tin chloride, triethylaluminum and heteropolyacid; zinc hexacyanocobal Tate; phosphazene compounds and the like. Among these, an alkali catalyst is preferable. Although the usage-amount of a catalyst is not specifically limited, Based on the weight of the polymer to produce | generate, Preferably it is 0.0001-10%, More preferably, it is 0.001-1%.

The polyol component (A) used in the present invention may contain another polyol (A2) having a valence of 3 or more in addition to the polyol (A1).
The other polyol (A2) is a compound having a structure in which the AO is added to the trivalent or higher active hydrogen-containing compound (A21) or the trivalent or higher active hydrogen-containing compound, and the polyhydric acid does not fall under (A1). Examples include ether polyol (A22), polyester polyol (A23), and polyol (A24) other than these.

As the polyester polyol (A23), a polyhydric hydroxyl group-containing compound (including the polyhydric alcohol and the polyether polyol) and a polycarboxylic acid (aromatic polycarboxylic acid and aliphatic polycarboxylic acid) or an anhydride thereof and Condensation reaction product with ester-forming derivatives (such as phthalic anhydride and dimethyl terephthalate) such as lower alkyl (alkyl group having 1 to 4 carbon atoms) ester; addition of carboxylic anhydride of polyhydric alcohol and AO Reactants; these AO (EO, PO, etc.) addition reactants; polylactone polyols {for example, those obtained by ring-opening polymerization of lactones (ε-caprolactone, etc.) using the polyhydric alcohol as an initiator}; and polycarbonate Polyol (for example, the polyhydric alcohol and alkylene carbonate) Reaction), and the like.
Aromatic polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, 2,2'-bibenzyldicarboxylic acid, trimellitic acid, hemilic acid, trimesic acid, pyromellitic acid and naphthalene-1,4 dicarboxylic acid, naphthalene Examples include aromatic polycarboxylic acids having 8 to 18 carbon atoms such as -2,3,6 tricarboxylic acid, diphenic acid, 2,3-anthracene dicarboxylic acid, 2,3,6-anthracentricarboxylic acid and pyrene dicarboxylic acid.
Examples of the aliphatic polycarboxylic acid include succinic acid, fumaric acid, sebacic acid, and adipic acid.

  Various polyols (A24) other than these include polymer polyols; polydiene polyols such as polybutadiene polyols and hydrogenated products thereof; acrylic polyols, JP-A 58-57413 and JP-A 58-57414. Hydroxyl group-containing vinyl polymers described in the above; natural oil-based polyols such as castor oil; modified products of natural oil-based polyols;

The polymer polyol described above is a polymer polyol in which polymer particles are dispersed in a polyol.
The polymer polyol can be produced by polymerizing a vinyl monomer in a polyol by a known method. For example, a polyol in which a vinyl monomer is polymerized in the presence of a radical polymerization initiator and a polymer of the obtained vinyl monomer is stably dispersed. Specific examples of the polymerization method include those described in US Pat. No. 3,383,351 and Japanese Examined Patent Publication No. 39-25737.
As the vinyl monomer, styrene and / or acrylonitrile is preferable.

  Of these trivalent or higher polyols (A2), polymer polyols are preferred among the active hydrogen-containing compounds (A21), polyether polyols (A22), and (A24).

  The content of the polyol (A1) based on the weight of the polyol component (A) is preferably 50 to 100%, more preferably 50 to 90%, particularly preferably 60 to 80% from the viewpoint of reducing the resonance frequency. It is. In the present invention, when the polyol (A1) is contained in the polymer polyol to be used, the polyol component (A) is treated as containing the polyol (A1).

  In the method for producing a flexible polyurethane foam of the present invention, a polyol component (A) and an organic polyisocyanate component (B) are sealed in the presence of a catalyst (C), a foaming agent (D) and a foam stabilizer (E). React in a frame to form polyurethane foam.

As the organic polyisocyanate component (B), all organic polyisocyanates used in polyurethane foams can be used. Aromatic polyisocyanates, linear or branched aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic aliphatic polyisocyanates. Examples thereof include isocyanates, modified products thereof (urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, isocyanurate groups and oxazolidone group-containing modified products), and mixtures of two or more thereof.
Aromatic polyisocyanates include aromatic diisocyanates having 6 to 16 C (excluding carbon in the NCO group; the following polyisocyanates are the same), aromatic triisocyanates having 6 to 20 C, and crude products of these isocyanates. Can be mentioned. Specific examples include 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′- and 4,4′-diphenylmethane diisocyanate ( MDI), polymethylene polyphenylene polyisocyanate (crude MDI), naphthylene-1,5-diisocyanate, and triphenylmethane-4,4 ′, 4 ″ -triisocyanate.

Examples of the linear or branched aliphatic polyisocyanate include C6-10 aliphatic diisocyanate. Specific examples include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and the like.
Examples of the alicyclic polyisocyanate include C6-16 alicyclic diisocyanate. Specific examples include isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate.

Examples of the araliphatic isocyanate include C8-12 araliphatic diisocyanate. Specific examples include xylylene diisocyanate and α, α, α ′, α′-tetramethylxylylene diisocyanate.
Specific examples of the modified polyisocyanate include carbodiimide-modified MDI.

  Among these, an aromatic polyisocyanate is preferable, and more preferable is one or more selected from TDI, crude TDI, MDI, crude MDI, and modified products of these isocyanates, and particularly preferable is productivity. For reasons such as improvement, the total content (%) of MDI, crude MDI, and / or modified products thereof is 10 or more (especially 15 to 80), and the content (%) of other polyisocyanates (especially TDI) Is 90 or less (particularly 20 to 85). The isocyanate group content (NCO%) of the organic polyisocyanate component (B) as a whole is preferably 25 to 45.

  As the catalyst (C), any catalyst that accelerates the urethanization reaction can be used, and tertiary amines (triethylenediamine, bis (N, N-dimethylamino-2-ethyl) ether and N, N, N ′, N ′ -Tetramethylhexamethylenediamine, etc.), carboxylic acid metal salts (potassium acetate, potassium octylate, stannous octylate, dibutylstannic dilaurate, lead octylate, etc.). From the viewpoint of tensile strength, the amount of catalyst used is preferably 0.01 to 5.0%, more preferably 0.2 to 3.0%, based on the weight of the polyol component (A).

  Examples of the foaming agent (D) include water and low-boiling compounds having a boiling point of 0 to 50 ° C.

Low boiling point compounds include hydrogen atom-containing halogenated hydrocarbons and low boiling point hydrocarbons. Specific examples of the hydrogen atom-containing halogenated hydrocarbon and low boiling point hydrocarbon include methylene chloride, HCFC (hydrochlorofluorocarbon) (HCFC-123, HCFC-141b, HCFC-142b, etc.); HFC (hydrofluorocarbon) (HFC- 152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa and HFC-365mfc), pentane and cyclopentane.
Among these, methylene chloride, HCFC-141b, HFC-134a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc and a mixture of two or more of these are preferable from the viewpoint of moldability. .

Of the foaming agent (D), the amount of water used alone is 0. 0 based on the weight of the polyol component (A) from the viewpoint of suppressing foam density at the time of foam formation and scorch generation. 1-30% is preferable, More preferably, it is 0.5-20%, Most preferably, it is 1.5-6%. The amount of water used in combination with other blowing agents is preferably 0.1 to 10.0%, more preferably 2.0 to 5.0%, based on the weight of the polyol component (A). .
The amount of the low boiling point compound used is preferably 40% or less, more preferably 5 to 30%, based on the weight of the polyol component (A), from the viewpoint of poor molding.

  As the foam stabilizer (E), any of those used in the production of ordinary polyurethane foams can be used. Dimethylsiloxane foam stabilizers [“SRX-253”, “PRX-607” manufactured by Toray Dow Corning Silicone Co., Ltd. ”And EVONIK's“ TEGOSTAB B8737 ”and the like, and polyether-modified dimethylsiloxane foam stabilizers (“ L-540 ”,“ SZ-1142 ”,“ L-3601 ”,“ L-3601 ”manufactured by Toray Dow Corning Silicone Co., Ltd.) SRX-294A ”and“ B-4900 ”manufactured by Degussa Japan Co., Ltd.]. The amount of the foam stabilizer used is preferably 0.2 to 3.0%, more preferably 0.5 to 2.5% based on the weight of the polyol component (A) from the viewpoint of tensile strength.

In the production method of the present invention, if necessary, other additives described below may be used and reacted in the presence thereof.
Other additives include colorants (dyes and pigments), flame retardants (such as phosphate esters and halogenated phosphate esters), anti-aging agents (such as triazole and benzophenone), and antioxidants (such as hindered phenols and hindered amines). ) And the like.

  In the production method of the present invention, the isocyanate index (index) [(NCO group / active hydrogen atom-containing group) equivalent ratio × 100] in production of the polyurethane foam is preferably 70 to 135 from the viewpoint of moldability. Preferably it is 75-130, Most preferably, it is 80-125.

  An example of a method for producing a flexible polyurethane foam according to the method of the present invention is as follows. First, a predetermined amount of a polyol component (A), a catalyst (C), a foaming agent (D), a foam stabilizer (E) and other additives as necessary are mixed. Subsequently, this mixture (polyol premix) and organic polyisocyanate component (B) are rapidly mixed using a flexible polyurethane foam foaming machine or a stirrer. The obtained mixed solution (foaming stock solution) is poured into a sealed mold (made of metal or resin, mold temperature 20 to 80 ° C.) heated as necessary to cause urethanization reaction, and after curing for a predetermined time, it is removed. Molded to obtain a flexible polyurethane foam. The mold foam packing ratio is preferably 100 to 300%.

The flexible polyurethane foam obtained by the present invention preferably has a core density (kg / m ³ ) of 40 to 60, and more preferably 42 to 58. When it is 40 or more, the wet heat compression residual strain ratio is good, and when it is 60 or less, the weight is light and the productivity is good.
The rebound resilience (%) is preferably 50 to 70, more preferably 55 to 68. When the impact resilience (%) is 50 to 70, the cushion feeling when the vehicle seat cushion material is used is good.

  According to the method of the present invention, a flexible polyurethane foam having a resonance frequency of 3.4 Hz or less and a vibration transfer rate (resonance transfer rate) at a resonance frequency of 3.0 or less, which is defined by the vibration transfer characteristics of JASCO B-407. Can be obtained. Since such a foam has a sufficiently low vibration transmissibility in a vibration region (4 to 10 Hz) in which a person feels uncomfortable, the riding comfort when a cushion material for a vehicle seat is good.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. Hereinafter, unless otherwise specified, parts are parts by weight.

<Examples 1 to 10, Comparative Examples 1 to 4>
Of the polyurethane foam raw materials in Examples and Comparative Examples, the polyol component (A) is as follows.
(1) Polyol (A1-1): obtained by adding PO to pentaerythritol using tris (pentafluorophenyl) borane as a catalyst and then adding EO, having a functional group number of 4.0, a hydroxyl value of 30, Polyoxyethylene polyoxypropylene polyol having a content of terminal EO units of 10.0%, a terminal hydroxyl group primary OH conversion ratio of 90%, a monool content of 0.03 meq / g, and a diol content of 16%.
(2) Polyol (A1-2): pentaerythritol obtained by adding PO using tris (pentafluorophenyl) borane as a catalyst and then adding EO, having a functional group number of 4.0, a hydroxyl value of 25, A polyoxyethylene polyoxypropylene polyol having a terminal EO unit content of 10.0%, a terminal hydroxyl group primary OH conversion ratio of 90%, a monool content of 0.03 meq / g, and a diol content of 18%.
(3) Polyol (A1-3): Polypentaerythritol obtained by adding PO using tris (pentafluorophenyl) borane as a catalyst and then adding EO, having a functional group number of 4.0, a hydroxyl value of 30, Polyoxyethylene polyoxypropylene polyol having a content of terminal EO units of 10.0%, a terminal hydroxyl group primary OH conversion of 80%, a monool content of 0.04 meq / g, and a diol content of 13%.
(4) Polyol (A1-4): After adding PO to pentaerythritol using tris (pentafluorophenyl) borane as a catalyst, and then adding EO, low-boiling diol is removed by distillation under reduced pressure to reduce the diol content. The number of functional groups was 4.0, the hydroxyl value was 40, the content of the terminal EO unit was 10.0%, the primary hydroxylation rate of the terminal hydroxyl group was 90%, the monool content was 0.02 meq / g, and the diol content was adjusted. 18% polyoxyethylene polyoxypropylene polyol.
(5) Polyol (A1-5): Pentoerythritol obtained by adding PO using tris (pentafluorophenyl) borane as a catalyst and then adding EO, having a functional group number of 4.0, a hydroxyl value of 30, A polyoxyethylene polyoxypropylene polyol having a terminal EO unit content of 12.0%, a terminal hydroxyl group primary OH conversion ratio of 93%, a monool content of 0.03 meq / g, and a diol content of 16%.
(6) Polyol (A1-6): PO is added to pentaerythritol using tris (pentafluorophenyl) borane as a catalyst, then EO is added, and then low-boiling diol is removed by distillation under reduced pressure to reduce the diol content. The number of functional groups was 4.0, the hydroxyl value was 30, the content of the terminal EO unit was 8.0%, the primary hydroxylation rate of the terminal hydroxyl group was 86%, the monool content was 0.03 meq / g, and the diol content. 18% polyoxyethylene polyoxypropylene polyol.
(7) Polyol (A1-7): obtained by adding PO to glycerin using tris (pentafluorophenyl) borane as a catalyst and then adding EO, having a functional group number of 3.0, a hydroxyl value of 30, and a terminal A polyoxyethylene polyoxypropylene polyol having an EO unit content of 10.0%, a terminal hydroxyl group primary OH conversion ratio of 90%, a monool content of 0.03 meq / g, and a diol content of 10%.

(8) Polyol (A2-1): POTA is added to pentaerythritol using potassium hydroxide as a catalyst, and then EO is added, resulting in a hydroxyl value of 30 and a content of terminal EO unit of 10.0% Polyoxyethylene polyoxypropylene polyol having a primary hydroxyl group conversion of 70%, a monool content of 0.07 meq / g, and a diol content of 0.0%.
(9) Polyol (A2-2): obtained by adding PO to pentaerythritol using potassium hydroxide as a catalyst, and then adding EO, having a functional group number of 4.0, a hydroxyl value of 30, and a terminal EO unit. A polyoxyethylene polyoxypropylene polyol having a content of 14.0%, a primary OH conversion rate of terminal hydroxyl groups of 82%, a monool content of 0.07 meq / g, and a diol content of 0.0%.
(10) Polyol (A2-3): obtained by adding PO to pentaerythritol using tris (pentafluorophenyl) borane as a catalyst and then adding EO, having a functional group number of 4.0, a hydroxyl value of 30, A polyoxyethylene polyoxypropylene polyol having a terminal EO unit content of 5.0%, a terminal hydroxyl group primary OH conversion ratio of 76%, a monool content of 0.06 meq / g, and a diol content of 3%.
(11) Polyol (A2-4): Average functional group number 4.0 obtained by block addition of PO and EO to pentaerythritol using potassium hydroxide as a catalyst, hydroxyl value 28, content of terminal EO unit 12 0.0%, terminal hydroxyl group primary OH conversion rate 80%, monool content 0.07 meq / g, diol content 0.0% polyoxyethylene polyoxypropylene polyol, and glycerin using potassium hydroxide as catalyst The average number of functional groups obtained by block addition of PO and EO is 3.0, the hydroxyl value is 34, the content of terminal EO units is 14.0%, the primary hydroxylation rate of terminal hydroxyl groups is 82%, the monool content is 0.06 meq. / G, in a mixture of polyoxyethylene polyoxypropylene polyols having a diol content of 0.0% (weight ratio: 20:80) Polymer polyol (polymer content: 33.0%) obtained by copolymerization of rilonitrile (weight ratio: 30/70), hydroxyl value 22.
(12) Polyol (A2-5): average functional group number 3.0, hydroxyl value 28.0, terminal EO unit content obtained by block addition of PO and EO to glycerin using potassium hydroxide as a catalyst In a polyoxyethylene polyoxypropylene polyol having an amount of 13.5%, a primary OH conversion rate of terminal hydroxyl group of 83%, a monool content of 0.08 meq / g, and a diol content of 0.0%, acrylonitrile and styrene are combined with acrylonitrile / Polymer polyol copolymerized with styrene = 67/33 (polymer content 30.0%), hydroxyl value 20.
(13) Polyol (A2-6): PO adduct of sorbitol. Hydroxyl value 490.
(14) Polyol (A2-7): Triethanolamine. Hydroxyl value 1120.

Among the raw materials of the flexible polyurethane foam in the examples and comparative examples, those other than the polyol component (A) are as follows.
1. Catalyst (C)
Catalyst (C-1): “DABCO-33LV” (33% dipropylene glycol solution of triethylenediamine) manufactured by Air Products Japan Co., Ltd.
Catalyst (C-2): “TOYOCAT ET” manufactured by Tosoh Corporation (70% dipropylene glycol solution of bis (dimethylaminoethyl) ether)
2. Foaming agent (D)
2. Foaming agent (D-1): water Foam stabilizer (E)
Foam stabilizer (E-1): “TEGOSTAB B8737” (polysiloxane foam stabilizer) manufactured by EVONIK

4). Organic polyisocyanate component (B)
Organic polyisocyanate (B-1): TDI-80 (2,4- and 2,6-TDI, ratio of 2,4-isomer is 80%) / crude MDI (average functional group number: 2.9) = 80 / 20 (weight ratio)

  Form a foam by foaming a flexible polyurethane foam in a mold under the following foaming conditions with the number of parts of the polyol premix shown in Table 1 and the amount of the organic polyisocyanate component (B) that gives the NCO index shown in Table 1. Thereafter, the physical properties of the flexible polyurethane foam after taking out from the mold and leaving it for a whole day and night were measured. The measured values of physical properties are also shown in Table 1, respectively.

(Foaming conditions)
Mold size: 400mm x 400mm x 100mm (height)
Mold temperature: 65 ° C
Mold material: Aluminum Mixing method: High pressure urethane foaming machine (manufactured by PEC) Polyol premix and organic polyisocyanate are mixed at 15 MPa.

-The measurement method and unit of foam physical properties are shown below.
Core density: Based on JIS K6400, the unit is kg / m ³ .
Foam hardness (25% -ILD): Conforms to JISK6400, unit is N / 314 cm ² .
Rebound resilience: Conforms to JIS K6400, unit is%.
Compression residual strain rate: Conforms to JIS K6400, unit is%.
Humid heat compression residual strain rate: Conforms to JIS K6400, temperature 50 ° C., humidity 95%. Units%.

・ Methods and units for testing vibration characteristics of foam properties are shown below.
Based on the test method of JASO B407, the resonance frequency (Hz) and the resonance transmissibility at this time were evaluated.

  In Table 1, the polyurethane foams of Examples 1 to 10 of the present invention have improved foam physical properties, particularly the resonance frequency of vibration characteristics and durability, compared with the polyurethane foams of Comparative Examples 1 to 4.

  The flexible polyurethane foam of the present invention obtained by the method for producing a flexible polyurethane foam of the present invention has better ride comfort and superior durability than conventional ones. Therefore, it is useful as a high vibration absorbing cushion material for a vehicle seat. In addition, the flexible polyurethane foam obtained by the production method of the present invention can be widely used for other uses in which a flexible polyurethane foam is usually used. For details of the use, for example, “Nikkan Kogyo Shimbun,” "Polyurethane resin handbook", pages 191 to 195 (1987).

Claims (4)

A flexible polyurethane foam in which a polyol component (A) containing the following polyol (A1) and an organic polyisocyanate component (B) are reacted in the presence of a catalyst (C), a foaming agent (D) and a foam stabilizer (E). A method for producing a flexible polyurethane foam, wherein a foam sample having a size of 400 mm × 400 mm × 100 mm of the obtained foam has a resonance frequency value of 3.4 Hz or less and a resonance transmissibility of 3.0 or less.
Polyol (A1): A polyether polyol that satisfies the following (1) to (6).
(1) The number average functional group number is 3-4.
(2) The proportion of primary hydroxyl groups in all terminal hydroxyl groups is 80 mol% or more.
(3) The hydroxyl value (mgKOH / g) is 25-40.
(4) The content of the terminal oxyethylene unit is 8 to 12% by weight based on the weight of (A1).
(5) The monool content is 0.04 meq / g or less.
(6) The diol content is 8 to 20% by weight.   The method for producing a flexible polyurethane foam according to claim 1, wherein the content of the polyol (A1) is 50 to 100% by weight based on the weight of the polyol component (A).   The flexible polyurethane foam obtained by the manufacturing method of Claim 1 or 2.   A vehicle seat cushion comprising the flexible polyurethane foam according to claim 3.