JP2003026749A - Method for producing flexible polyurethane foam - Google Patents

Abstract

[PROBLEMS] To provide a method for producing a flexible polyurethane foam having low density, high elasticity, excellent durability, and good ride comfort. SOLUTION: MDI (A1), polymethylene polyphenylene polyisocyanate (A2), TDI (A3),
Using a polyisocyanate composition (A) obtained from a polyol (A4) and a compound having two or more active hydrogens as an initiator, an alkylene oxide having 3 or more carbon atoms is used as an initiator.
An alkylene oxide containing 0% by mass or more is added, and ethylene oxide is further added to the terminal at 10 to 30% by mass.
A polyol composition (B) containing 40% by mass or more of a polyether polyol (a) having a monool concentration of 30 mol% or less and a number average molecular weight of 2,000 to 10,000, which is obtained by addition, is used as a catalyst ( C), foaming agent (D),
Production of a flexible polyurethane foam which is reacted in the presence of a foam stabilizer (E).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD 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 having a low density, excellent vibration absorption and sitting comfort, and particularly suitable for molding a seat cushion for automobiles.

[0002]

2. Description of the Related Art Flexible polyurethane foams have been used in various fields such as cushioning materials for various vehicles, furniture, carpets, etc. due to their excellent cushioning properties. The flexible polyurethane foam is produced by reacting an organic polyisocyanate composition and a polyol composition in the presence of a foaming agent, a catalyst, a foam stabilizer, and optionally other auxiliary agents. This organic polyisocyanate composition,
Conventionally, tolylene diisocyanate (hereinafter abbreviated as TDI)
Was the main component, but recently diphenylmethane diisocyanate (hereinafter abbreviated as MDI) and MDI
A mixture containing polymethylene and polymethylene polyphenylene polyisocyanate (hereinafter abbreviated as “polymeric MDI”) as a main component is often used. Moreover, as the polyol, a polyether polyol obtained by addition-polymerizing an alkylene oxide such as ethylene oxide or propylene oxide to an active hydrogen-containing substance is generally used.

The flexible polyurethane foam used as a cushioning material for vehicles has an appropriate hardness, a good impact resilience and mechanical properties (strength, elongation, etc.), a small compression set, a low vibration transmissibility at a frequency of 6 Hz or more, etc. It is required to meet a wide range of items. The frequency is 6 Hz because it is known that the human internal organs (especially the stomach) resonate with the vibration around 6 Hz.

In recent years, in order to meet the demands for energy saving, high productivity, ensuring a safety and health environment at the production site, etc.,
A method for producing a flexible polyurethane foam using an organic polyisocyanate composition containing polymeric MDI as a main component has been proposed. This is the Polymeric MDI
This is because TDI is more reactive, less toxic, and has a lower vapor pressure than TDI, which is excellent in work safety, and the resulting flexible polyurethane foam has good physical properties.

For example, JP-A-7-330850 discloses an isocyanate group-terminated prepolymer obtained by reacting a polymeric MDI with a polyether polyol mainly composed of a trifunctional or higher functional C3 or higher oxyalkylene group. A method for producing a low-density, high-elasticity flexible polyurethane foam using an organic polyisocyanate composition comprising a polymer and TDI is shown.

[0006]

However, in the conventional method for producing a low-density flexible polyurethane foam, the vibration absorbing property, that is, the riding comfort is hardly considered. In order to suppress motion sickness, it is necessary to suppress the vibration transmissibility at a frequency near 6 Hz. Further, the deterioration of the durability of the foam due to the low density has not been discussed so far. An object of the present invention is to provide a method for producing a flexible polyurethane foam having low density and high elasticity, excellent durability, a vibration transmissibility at a frequency of about 6 Hz or less and a good riding comfort. is there. The vibration transmissibility of 1 time or less means that the output transmitted with respect to the input vibration is small, that is, the flexible polyurethane foam serves as a cushioning material.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made earnest studies and studies for the purpose of providing a method for producing a flexible polyurethane foam having low density and high elasticity, excellent durability and good riding comfort. As a result of repeating, it was found that a method for producing a flexible polyurethane foam using an organic polyisocyanate composition having a specific composition and a polyol composition having a specific composition solves these problems, and has completed the present invention.

That is, the present invention provides the following (1) to (4):
Is shown in. (1) Using MDI (A1), polymethylene polyphenylene polyisocyanate (A2), TDI (A3), polyisocyanate composition (A) obtained from polyol (A4) and a compound having two or more active hydrogens as an initiator By adding an alkylene oxide containing 50% by mass or more of an alkylene oxide having 3 or more carbon atoms,
Furthermore, the monool concentration obtained by adding 10 to 30% by mass of ethylene oxide to the terminal is 30 mol% or less,
A polyol composition (B) containing 40 mass% or more of a polyether polyol (a) having a number average molecular weight of 2,000 to 10,000, a catalyst (C), a foaming agent (D), a foam stabilizer (E). ) In the presence of a flexible polyurethane foam, (A1) is 4,4'-MDI
Containing 2 to 60 mass% of isomers other than
The ratio (mass ratio) of (A1) and (A2) is (A1) /
(A2) = 30/70 to 95/5, the proportion of (A3) in the polyisocyanate composition (A) is 45% by mass or less, and the resulting flexible polyurethane foam has an apparent total density of 50 kg / m ³ or less. , Impact resilience is 60%
As described above, the method for producing a flexible polyurethane foam is characterized in that the vibration transmissibility at a frequency of 6 Hz or higher is 1 time or less and the repeated compression set is 2% or less.

(2) Production of the flexible polyurethane foam according to the above (1), characterized in that the proportion (mass ratio) of the polyol (A4) in the polyisocyanate composition (A) is 3 to 40% by mass. Method.

(3) The polyol (A4) is obtained by adding an alkylene oxide containing 50% by mass or more of an alkylene oxide having 3 or more carbon atoms, using a compound having two or more active hydrogens as an initiator, and further adding it to the terminal. Obtained by adding 10 to 30 mass% of ethylene oxide, the monool concentration is 30 mol% or less, and the number average molecular weight is 2,
000-10,000 polyether polyol (ii) and / or a compound having two or more active hydrogens as an initiator, an alkylene oxide having 50% by mass or more of ethylene oxide is added, and a number average molecular weight of 500- The method for producing a flexible polyurethane foam according to the above (1) or (2), which comprises 10,000 polyether polyol (b).

(4) The polyol composition (B) is characterized by containing 1 to 20 mass% of polymer fine particles,
The method for producing a flexible polyurethane foam according to any one of (1) to (4) above.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The present invention comprises a specific polyisocyanate composition (A),
A specific polyol composition (B) is 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 having specific physical properties.

First, the raw materials used in the present invention will be described. Isocyanate composition (A) in the present invention
Is obtained from MDI (A1), polymethylene polyphenylene polyisocyanate (A2), TDI (A3) and polyol (A4).

The MDI (A1) used in the present invention has two isocyanate groups and two benzene rings, and is called a binuclear body. The polymethylene polyphenylene polyisocyanate (A2) has an isocyanate group and three or more benzene rings each, and is called a polynuclear body. (A1) is supplied in the form of a single product or a mixture with (A2), and (A2) is supplied as (A
It is supplied in the form of a mixture with 1). Hereinafter, in the present invention, the mixture of (A1) and (A2) is referred to as polymeric MDI.

In (A1), 2, 2'-MDI, 2,
There are three types of isomers, 4'-MDI and 4,4'-MDI. The isomer composition ratio of (A1) is 4,4′-MDI.
Other than isomers, namely 2,2'-MDI and 2,4'-
The total content of MDI is preferably 2 to 60% by mass, more preferably 5 to 55% by mass. When the total content of 2,2′-MDI and 2,4′-MDI is less than the lower limit,
The low-temperature storage stability of the polyisocyanate (B) tends to decrease. If the upper limit is exceeded, the hardness of the resulting flexible polyurethane foam tends to decrease.

The ratio (mass ratio) of (A1) and (A2) is preferably (A1) / (A2) = 30/70 to 95/5, and (A1) / (A2) = 33/68 to 93/7. Is more preferable, and (A1) / (A2) = 35 / 65-91 / 9
Is particularly preferable. If the content of (A1) is too small, the flexibility of the foam is lost and the foam physical properties such as elongation are likely to deteriorate. If the amount of (A1) is too large, the cells become unstable and the moldability of the foam is likely to deteriorate.

(A3) is 2,4-TDI, 2,6-T
Any mixture of DI, preferably 2,4-TDI
/ 2,6-TDI = 90/10 to 70/30, more preferably 2,4-TDI / 2,6-TDI = 85/15 to
It is a mixture of 75/25 (both in mass ratio). In the present invention, the TDI in the polyisocyanate composition (A) is
The content is 45% by mass or less, and preferably 1 to 40% by mass, more preferably 5 to 3 in consideration of the working environment at the time of manufacturing the flexible polyurethane foam, foam physical properties and the like.
5% by mass, particularly preferably 10 to 30% by mass.

If desired, polyisocyanates other than the above isocyanates may be used in combination. For example,
Xylene diisocyanate, nitrodiphenyl diisocyanate, diphenyl propane diisocyanate, dimethyl diphenyl methane diisocyanate, phenylene diisocyanate, naphthylene diisocyanate, dimethoxy diphenyl diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, methyl pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated TDI, hydrogenation Xylene diisocyanate, hydrogenated MDI, tetramethyl xylene diisocyanate, polymeric products thereof, urethane modified products thereof, urea modified products, allophanate modified products, biuret modified products, carbodiimide modified products, uretonimine modified products, uretdione modified products, isocyanurates Sex body, and further mixtures of two or more thereof.

(A4) is not particularly limited, but a compound having two or more active hydrogens is used as an initiator, an alkylene oxide containing 50% by mass or more of an alkylene oxide having 3 or more carbon atoms is added, and the terminal is further added. It is obtained by adding 10 to 30 mass% of ethylene oxide to (EO
Chip amount is 10 to 30% by mass), monool concentration is 30 mol% or less, and number average molecular weight is 2,000 to 1
A number average molecular weight of 500 to 500 is obtained by adding an alkylene oxide having 50% by mass or more of ethylene oxide to an initiator containing a compound containing 10,000 polyether polyols (a) or a compound having two or more active hydrogens as an initiator.
It is preferable that the polyether polyol (B) having a content of 10,000 is contained. Also, (a),
In both (b), the number of active hydrogen functional groups of the initiator is more preferably 2 to 6, and most preferably 3 to 5.

Examples of such initiators (a) and (b) are:
Ethylene glycol, 1,2-propanediol, 1,
3-propanediol, 1,2-butanediol, 1,
3-butanediol, 1,4-butanediol, 1,5
-Pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,
6-hexanediol, neopentyl glycol, 1,
8-octanediol, 1,9-nonanediol, 2,
2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,
2,4-trimethyl-1,3-pentanediol, 2-
Ethyl-1,3-hexanediol, 2-n-hexadecane-1,2-ethylene glycol, 2-n-eicosane-1,2-ethylene glycol, 2-n-octacosane-1,2-ethylene glycol, diethylene glycol, Dipropylene glycol, 1,4-cyclohexanedimethanol or ethylene oxide or propylene oxide adduct of bisphenol A, hydrogenated bisphenol A, 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-dimethylpro Low molecular weight polyols such as pionate, trimethylolpropane, glycerin and pentaerythritol, aniline, ethylenediamine, propylenediamine, tolylenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine. Low molecular amines such as down, monoethanolamine, diethanolamine, triethanolamine, and low molecular aminoalcohols such as N- methyl diethanolamine.

Examples of the alkylene oxide having 3 or more carbon atoms include propylene oxide and butylene oxide. In the present invention, propylene oxide is preferred.

(A) The ring-opening polymerization of an alkylene oxide having 3 or more carbon atoms with the above-mentioned initiator in the presence of a potassium-based catalyst, a complex metal cyanide complex, or a cesium-based catalyst, alone or in combination of 2 or more, Then add ethylene oxide to 10
It is obtained by adding -30 mass%, preferably 12-28 mass%. The number average molecular weight of (a) thus obtained is 2,000 to 10,000, preferably 3,000 to 9,500, and particularly preferably 3,500.
~ 9,000. The monool concentration is 30 mol% or less, preferably 28 mol% or less. The amount of (a) relative to the polyisocyanate composition (A) is 3 to.
40% by mass is preferable, and particularly preferably 5 to 35% by mass.
Is.

(B) can be obtained by adding alkylene oxide having 50% by mass or more of ethylene oxide to the above-mentioned initiator. Specifically, it can be obtained by adding a mixture of alkylene oxide having 3 or more carbon atoms and ethylene oxide, or by adding ethylene oxide only. The number average molecular weight of (b) thus obtained is 500 to 10,000,
Preferably 600 to 9,000, more preferably 100
It is 0-8,500. The content of the ethylene oxide unit is 50% by mass or more, and preferably 54% or more. Particularly preferably, it is 58 mass% or more. The amount of (b) relative to the polyisocyanate composition (A) is 3
-40 mass% is preferred, and especially preferred is 5-35 mass%.

When the number of functional groups of the initiator (a) is less than the lower limit, the resulting flexible polyurethane foam has a reduced crosslink density, resulting in a decrease in strength and hardness and a deterioration in dynamic durability. Further, when the number average molecular weight is less than the lower limit, the physical properties are lowered and the impact resilience is lowered, and when it exceeds the upper limit, the hardness tends to be insufficient. When the monool concentration exceeds the upper limit, elasticity and vibration absorption tend to decrease. If the amount of ethylene oxide added is too large, the hardness tends to decrease, and if it is too small, the impact resilience of the foam tends to decrease. Furthermore,
If the amount of (a) relative to the polyisocyanate composition (A) is too small, problems such as deterioration of the impact resilience performance of the foam, deterioration of cell stability during production and deterioration of formability of the foam occur. If the amount of (a) is too large with respect to the polyisocyanate composition (A), the liquid viscosity increases, and the handling convenience and the foam moldability deteriorate.

When the number of functional groups of the initiator (b) is less than the lower limit, the resulting flexible polyurethane foam is liable to have reduced strength and hardness due to reduction of crosslink density, and the dynamic durability of the foam. . Further, when the number average molecular weight is less than the lower limit, the physical properties are lowered and the impact resilience is lowered, and when it exceeds the upper limit, the hardness tends to be insufficient. If the added amount of ethylene oxide is too small, the rebound resilience of the foam tends to decrease. Further, if the amount of (b) relative to the polyisocyanate composition (A) is too small, problems such as deterioration of the impact resilience performance of the foam and deterioration of cell stability during production and deterioration of formability of the foam may occur. Occurs.
If the amount of (ii) relative to the polyisocyanate composition (A) is too large, the liquid viscosity will increase, resulting in poor handling convenience and foam formability.

In the present invention, "monool concentration"
Is a value calculated based on the ¹³ C-NMR spectrum measured using heavy acetone as a solvent. For the measurement method and spectrum attribution, see Journal of App.
lied PolymerScience, Vol. 5
2, 1015-1022 (1994).
H. Follow Carr's report.

In the above-mentioned report, the amount of monool was quantified from the integrated value of the unsaturated bond (C = C) of the terminal allyl group, which appears at a specific chemical shift (110 to 140 ppm) in the ¹³ C-NMR spectrum. , A method for calculating the amount of unsaturated bonds present in the polyol, that is, the monool concentration is described.

In the present invention, if necessary, (A4)
As the above, polyols other than (a) and (b), such as polyester polyol and polycarbonate polyol, can be used in combination. In this case, the amount is preferably 50% by mass or less of (a) or (b).

The polyisocyanate composition (A) used in the present invention is obtained by using the above-mentioned (A1) to (A4), and it is essential that (A4) is an isocyanate group-terminated prepolymer. There is no particular limitation other than that. That is, the isocyanate component in the isocyanate group-terminated prepolymer is not particularly limited, but the preferred isocyanate component is (A
1) to (A3).

The urethanization reaction temperature for obtaining the isocyanate group-terminated prepolymer is preferably 20 to 120 ° C, and particularly preferably 40 to 100 ° C. In addition, during the urethanization reaction, an organic metal compound such as dibutyltin dilaurate or dioctyltin dilaurate, a known urethanization catalyst such as an organic amine such as triethylenediamine or triethylamine, or a salt thereof can be used, if necessary.

The isocyanate content of the polyisocyanate composition (A) is preferably 20 to 35% by mass, more preferably 23 to 33% by mass. The viscosity at 25 ° C. is preferably 1800 mPa · s or less, more preferably 1200 mPa · s or less, and particularly preferably 50.
It is 0 mPa · s or less. If the isocyanate content is less than the lower limit, the viscosity tends to increase, and if it exceeds the upper limit, scorch inside the foam tends to occur. On the other hand, when the viscosity exceeds the upper limit, the flowability of the foam is lowered and the filling property in the mold is likely to be deteriorated.

The polyol composition (B) used in the present invention contains the above-mentioned (a) in an amount of 40% by mass or more, preferably 50% by mass or more, and particularly preferably 65% by mass or more.

When the number of functional groups of the initiator of the polyol (a) is less than the lower limit, the resulting flexible polyurethane foam is apt to have reduced strength and hardness due to reduced crosslink density. Also,
When the number average molecular weight is less than the lower limit, the physical properties and the impact resilience are lowered, and when it exceeds the upper limit, the hardness tends to be insufficient. If the monool concentration exceeds the upper limit, the vibration absorption tends to decrease. If the amount of ethylene oxide added is too large, the hardness tends to decrease, and if it is too small, the elasticity of the foam tends to decrease.

In the polyol composition (B), fine polymer particles obtained by dispersing one or more vinyl monomers or by polymerizing a polyisocyanate with an active hydrogen group-containing compound having a molecular weight of 18 to 200 are dispersed. be able to. This may be one in which the polymerization is directly carried out in the polyol (a) to adjust the amount of polymer, or a type in which the polymer fine particle content is high and a type in which the polymer fine particle content is low and / or a type which does not include the polymer fine particles are mixed. The content of the polymer fine particles in (B) thus obtained is 1 to 20% by mass, preferably 2 to 18% by mass.

If the content of the polymer fine particles in (B) is less than the lower limit, the hardness of the resulting flexible polyurethane foam tends to decrease. On the other hand, when the amount exceeds the upper limit, the viscosity of the polyol composition (B) becomes high, and the workability is likely to deteriorate.

For the purpose of adjusting strength and hardness, the polyol composition (B) may be used in combination with polyether polyol, polyester polyol, polycarbonate polyol or the like other than (a).

As the catalyst (C), various urethanization catalysts known in the art can be used. For example, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N, N, N ', N'-tetramethylhexamethylenediamine, N, N, N', N '. ,
N ″ -pentamethyldiethylenetriamine, bis- (2
-Dimethylaminoethyl) ether, triethylenediamine, 1,8-diaza-bicyclo (5,4,0) undecene-7,1,2-dimethylimidazole, tertiary amines such as 1-butyl-2-methylimidazole, dimethyl Reactive amines such as ethanolamine, N-trioxyethylene-N, N-dimethylamine, N, N-dimethyl-N-hexanolamine, or their organic acid salts, stannas octoate, dibutyltin dilaurate, naphthenes Examples thereof include organic metal compounds such as zinc acid. The preferable addition amount of the catalyst (C) is 0.01 to 10 mass% with respect to the polyol composition (B).

In the present invention, carbon dioxide gas generated by the reaction of an isocyanate group and water can be mainly used as the foaming agent (D), but a small amount of cyclopentane, isopentane, normal pentane, HFC-245 is additionally used.
A low boiling point organic compound such as fa may be used in combination, or air, nitrogen gas, liquefied carbon dioxide or the like may be mixed and dissolved in the undiluted solution using a gas loading device for molding. The preferred blowing agent in the present invention is water. The preferable amount of the foaming agent (D) added depends on the set density of the product to be obtained, but
1.5 to 10% by mass based on the polyol composition (B)
Is.

As the foam stabilizer (E), an organic silicon type surfactant known in the art can be used. For example, L-520, L-540 and L-5 manufactured by Nippon Unicar Co., Ltd. can be used.
309, L-5366, SZ-1306, Toray Dow Corning SRX-274C, SF-2962, SF
-2964, DC-5169, D manufactured by Air Products
C-193, Shin-Etsu Chemical F-122, F-22
0, F-341 and the like. The preferable amount of the foam stabilizer (E) added is 0.1 with respect to the polyol composition (B).
10 to 10% by mass.

In the present invention, a crosslinking agent may be used for the purpose of improving physical properties and adjusting hardness. The molecular weight of the cross-linking agent is preferably 61 to 500, more preferably 61 to 200. The preferred active hydrogen group of the cross-linking agent is a hydroxyl group or an amino group.

Particularly preferred cross-linking agents are low molecular weight polyamines such as ethylenediamine, hexamethylenediamine, diethylenetridiamine, tolylenediamine, diethyltolylenediamine, diaminodiphenylmethane and isophoronediamine, monoethanolamine, diethanolamine and triamine. Low molecular weight amino alcohols such as ethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, N-methyl-diethanolamine, N-phenyl-dipropanolamine and the like, and alkylene oxide to the aforementioned low molecular weight polyamine and low molecular weight amino alcohol. Examples thereof include added compounds.

Further, in the present invention, a flame retardant, a plasticizer, an antioxidant, an ultraviolet absorber, a colorant, various fillers, an internal release agent, and other processing aids may be added and used, if necessary. it can. Among these auxiliaries, those which do not have active hydrogen capable of reacting with isocyanate can be used by premixing with polyisocyanate.

Next, a concrete manufacturing procedure and the like will be described. Usually, as a method for producing a flexible polyurethane foam, preferably, other than the polyisocyanate composition (A),
A polyol premix prepared by previously mixing a polyol (B), a catalyst (C), a foaming agent (D), a foam stabilizer (E), an optional cross-linking agent, an additive, etc. is prepared, and this is mixed with a polyisocyanate composition. This is a method of mixing and foaming the two components of (A). The mixing method of the two components is an injector equipped with a known mechanical stirrer or a high pressure collision mixing method. Then, the mixed solution is poured into a predetermined mold to manufacture a flexible polyurethane foam. At that time, it is desirable that the mold is adjusted in the range of 30 to 80 ° C. in order to uniformly cure and obtain a sufficient expansion ratio.
A shorter demolding time is preferable from the viewpoint of production efficiency, and in the present invention, demolding can be performed within 3 to 8 minutes after injection, but a demolding time suitable for the conditions of the production equipment is arbitrarily set to reduce the defective rate. You can also Although the product after demolding can be used as it is, it is also possible to stabilize the appearance and dimensions of the product by compressing or decompressing the cells obtained by a conventionally known method to break the cells.

The isocyanate group / active hydrogen group equivalent ratio at this time is 0.5 to 1.5, preferably 0.7 to 1.3.
Is the range.

The flexible polyurethane foam thus obtained has an apparent total density of 50 kg / m ³ or less (preferably 47 kg / m ^3).
m ³ or less) and a low density of rebound resilience of 60% or higher, 1-fold vibration transmissibility at the frequency 6Hz more or less, repeated compression permanent set of 2% or less, excellent ride quality, dynamic durability Achieved sexual improvement.

The vibration transmissibility is 400 mm in length and 400 m in width.
It is a value when a 50 kg iron polishing board was placed on a test piece having a thickness of m and a thickness of 100 mm, and the vibration table was vibrated up to 1 to 20 Hz with a total amplitude of 5 mm. The test conditions are JASO-B4.
According to 07 regulations. JASO is an automobile standard established by the Society of Automotive Engineers of Japan.

The apparent total density, impact resilience, 50% compression set, tensile strength, breaking elongation and tear strength are JIS-
It is a value measured according to the K6400 standard.

The "dynamic durability" in the present invention means
This is a factor obtained by continuously and repeatedly compressing a foam and measuring the change in the thickness of the foam after a specified time. In contrast to the widely used (50%) compression set, a dynamic load can be applied to the foam to determine its durability according to the actual usage of the foam such as a vehicle seat.

This "dynamic durability" is defined by JIS-K640.
In accordance with 0, a foam having a thickness of 100 mm × 100 mm × 50 mm is compressed to 25 mm at a rate of 60 times / minute under an atmospheric condition of 30 ° C. × 80% RH, and a rate of change in thickness after 80,000 times compression (repeated compression) Permanent strain) was used as an index of dynamic durability.

[0050]

As described above, the flexible polyurethane foam according to the present invention is lightweight and excellent in impact resilience, and
It has excellent vibration absorption. The flexible polyurethane foam obtained by the present invention is a cushioning material for furniture such as sofas, clothes, mattresses, bedding such as mattresses, pillows, sound absorbing materials, sound insulating materials, household electrical appliances, electronic parts, industrial seals. It is useful as a material, packing material, daily sundries, etc., especially for automobiles, motorcycles, cushioning materials for railway vehicles,
It is useful as an interior material for automobiles.

[0051]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples and comparative examples, "%" means "mass%".
And “ratio (ratio)” indicates “mass ratio (ratio)”.

[Synthesis of Organic Polyisocyanate Composition] Synthesis Example 1 Capacity equipped with stirrer, cooling tube, nitrogen introducing tube, thermometer: 1
In a reactor of 00L, 5 kg of MDI (1), MDI
(2) 15kg, MDI (3) 20kg, P-MD
25 kg of I (2) was charged and heated to 40 ° C. with stirring. Next, 10 kg of polyol (3), 10 kg of polyol (5) and 10 kg of polyol (6) were charged, and reacted at 80 ° C. for 4 hours while stirring. Then, 5 kg of TDI (1) was charged to obtain a polyisocyanate composition NCO-1. The isocyanate content of NCO-1 was 22.5%, and the viscosity at 25 ° C was 600 mPa · s.

Synthesis Example 2 Using the same device as in Synthesis Example 1, MDI (3) was 40 k
g, 13 kg of TDI (1) was charged, and while stirring, 50
Warmed to ° C. Next, 7 kg of polyol (1) was charged and reacted at 90 ° C. for 3 hours while stirring. Then, 20 kg of P-MDI (2) and 20 kg of P-MDI (3) were charged to prepare a polyisocyanate composition NCO-2.
Got The isocyanate content of NCO-2 is 31.1
%, The viscosity at 25 ° C. was 150 mPa · s.

Synthesis Example 3 Using the same apparatus as in Synthesis Example 1, P-MDI (2) was added to 21
Charge 10 kg of TDI (1) and 4 while stirring.
Warmed to 0 ° C. Next, 5 kg of polyol (2),
Charge 12 kg of polyol (5) and stir it with stirring 60
The reaction was carried out at 0 ° C for 5 hours. After that, MDI (1) 24
28 kg of MDI (2) was charged to obtain a polyisocyanate composition NCO-3. NCO-3 has an isocyanate content of 28.1% and a viscosity at 25 ° C of 250 mPa · s.
It was s.

Using the same apparatus as in Synthesis Example 1, MDI
15 kg of (1) and 20 kg of MDI (3) were charged and heated to 60 ° C. with stirring. Next, 5 kg of polyol (1), 5 kg of polyol (4) and 10 kg of polyol (6) were charged, and the mixture was stirred at 65 ° C. for 7 hours.
Reacted for hours. After that, P-MDI (1) 10k
35 g of TDI (1) was charged to obtain a polyisocyanate composition NCO-4. NCO-4 has an isocyanate content of 30.5% and a viscosity at 25 ° C of 180 mPa · s.
Met.

Using an apparatus similar to Synthesis Example 1, MDI
(2) 20 kg, P-MDI (2) 40 kg, TD
20 kg of I (1) was charged and heated to 55 ° C. with stirring. Then, 20 kg of polyol (5) was charged and reacted at 65 ° C. for 7 hours while stirring. After that, P-
10 kg of MDI (1) and 35 kg of TDI (1) were charged to obtain a polyisocyanate composition NCO-5. NC
The isocyanate content of O-5 was 28.2%, and the viscosity at 25 ° C was 280 mPa · s.

Polyisocyanates NCO-6 to 8 were obtained using the raw materials shown in Table 1 in the same procedure and apparatus as in Synthesis Example 1.

[0058]

[Table 1]

[Synthesis of Polyol Composition] Blend Examples 1 to 7 Polyol premixes OH-1 to OH-7 were prepared by blending a polyol, a catalyst, water, a foam stabilizer and a crosslinking agent in the proportions shown in Table 2.

[0060]

[Table 2]

In Synthesis Examples 1 to 8 and Tables 1 and 2, MDI (1): MDI                       Content of isomers = 0% MDI (2): MDI                       Content of isomers = 30% MDI (3): MDI                       Content of isomers = 55% P-MDI (1): Polymeric MDI                       Dinuclear content = 40%                       Content of isomers in binuclear body = 1% P-MDI (2): Polymeric MDI                       Dinuclear content = 35%                       Content of isomers in binuclear body = 12% P-MDI (3): Polymeric MDI                       Dinuclear content = 50%                       Content of isomers in binuclear body = 15% * Isomer → Indicates an isomer other than 4,4'-MDI.         (2,2'-MDI and 2,4'-MDI) TDI (1): TDI                       2,4-TDI / 2,6-TDI = 80/20 TDI (2): TDI                       2,4-TDI / 2,6-TDI = 99/1 Polyol (1): Polyether polyol                       Initiator = ethylene glycol                       EO / PO = 100/0                       Number average molecular weight = 600 Polyol (2): Polyether polyol                       Initiator = Glycerin                       EO / PO = 70/30                       Number average molecular weight = 2,000 Polyol (3): Polyether polyol                       Initiator = Sorbitol                       EO / PO = 85/15                       Number average molecular weight = 6,000 Polyol (4): Polyether polyol                       Initiator = Glycerin                       Number average molecular weight = 3,000                       Monool concentration = 22 mol%                       EO chip amount = 12% Polyol (5): Polyether polyol                       Initiator = pentaerythritol                       Number average molecular weight = 8,000                       Monool concentration = 19 mol%                       EO chip amount = 19% Polyol (6): Polyether polyol                       Initiator = trimethylolpropane                       Number average molecular weight = 4,000                       Monool concentration = 27 mol%                       EO chip amount = 28% Polyol (7): Polyether polyol                       Initiator = Glycerin                       Number average molecular weight = 7,000                       Monool concentration = 15 mol%                       EO chip amount = 20% Polyol (8): Polyether polyol                       Initiator = pentaerythritol                       Number average molecular weight = 8,500                       Monool concentration = 22 mol%                       EO chip amount = 17% Polyol (9): Polyether polyol                       Initiator = Propylene glycol                       Number average molecular weight = 5,000                       Monool concentration = 28 mol%                       EO chip amount = 24% Polyol (10): Polyether polyol                       Initiator = Glycerin                       Number average molecular weight = 6,000                       Monool concentration = 40 mol%                       EO chip amount = 15% * EO: oxyethylene group, PO: oxypropylene group. Polyol (11): Acrylonitrile and styrene are used together in polyol (8)                       Polymerized polymer polyol                       Polymer fine particle content = 20% Polyol (12): Acrylonitrile and styrene are used together in the polyol (7).                       Polymerized polymer polyol                       Polymer fine particle content = 38% DETDA: diethyl tolylenediamine (molecular weight 178) TELA: triethanolamine (molecular weight 105) DC-5169: Silicone foam stabilizer (manufactured by Air Products) L-5309: Silicone foam stabilizer (manufactured by Nippon Unicar) B-4113: Silicone foam stabilizer (made by Gold Schmidt) TEDA L-33: amine catalyst (manufactured by Tosoh Corporation) Toyocat ET: amine catalyst (manufactured by Tosoh Corporation)

[Production and Evaluation of Flexible Polyurethane Foam] Example 1 Using NCO-2 and OH-1, a flexible polyurethane foam was foamed in a mold, then taken out from the mold and immediately subjected to roller crushing. Then, the molded product after crushing was allowed to stand for a whole day and night, and various physical properties of the foam were measured according to JIS-K6400. The results are shown in Table 3.

[0063] [Bubbling conditions] Mold shape: 400mm × 400mm × 100mm Mold material: Aluminum Mold temperature: 60 ± 2 ℃ Mixing method: High pressure machine mixing Raw material temperature: 25 ± 2 ℃ Cure conditions: 60 ± 2 ℃, 6 minutes Crushing conditions: 5-stage roller 80% compression

Examples 2 to 5 and Comparative Examples 1 to 5 In the same manner as in Example 1, flexible polyurethane foams were produced with the combinations shown in Tables 3 and 4, and the physical properties of various foams were measured. Tables 3 and 4 show the results of measuring the physical properties of the foam.

[0065]

[Table 3]

[0066]

[Table 4]

Physical property measuring method Apparent total density: Measured according to JIS-K6400 25% Compressive strength: Measured according to JIS-K6400 Sample size: 400 mm × 400 mm × 100 mm Rebound resilience (ball rebound): JIS-K6400
50% compression set (thickness change rate): JIS-K64
Sample size: 50 mm × 50 mm × 30 mm Measurement atmosphere: 70 ° C. and 50 ° C. × 95% RH ・ Tensile strength: Measured according to JIS-K6400 ・ Tear strength: Measured according to JIS-K6400 ・ At break Elongation: Measured according to JIS-K6400 ・ Vibration test: Measured according to JASO-B407 Sample size: 400 mm × 400 mm × 100 mm Grinding plate: made of iron, 50 kg Amplitude: 5 mm Frequency: 1 to 20 Hz ・ Repeated compression set (thickness) Change rate): JIS-K6
Measured according to 400 Sample size: 100 mm x 100 mm x 50 mm Compressed atmosphere: 30 ° C x 80% RH Compression repetition rate: 80,000 times Compression rate: 60 times / min Riding comfort: Soft polyurethane foam molded on a sensory test sheet Is actually installed in a passenger car, and a person sits down to check the riding comfort while driving.

As shown in Table 3, the polyisocyanate composition and the polyol composition of the present invention were mixed with a catalyst,
As a result of foaming in the presence of a foaming agent and a foam stabilizer, the apparent total density was as low as 50 kg / m ³ or less, the impact resilience was as high as 60% or more, and the vibration absorption performance and dynamic durability at 6 Hz were excellent. A flexible polyurethane foam could be obtained. On the other hand, as shown in Table 4, with a combination of a polyisocyanate composition and a polyol composition other than the present invention, a low density can be achieved, but a reduction in impact resilience, vibration absorption performance, and dynamic durability are achieved. The problems such as the deterioration of were exposed.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takao Fukami             4-20-20 Kugenuma Beach, Fujisawa City, Kanagawa Prefecture F-term (reference) 4J034 BA06 CA02 CA03 CA04 CA05                       CB02 CB04 CB05 CB07 CC03                       HA06 HA07 HA09 HA14 HC12                       HC64 HC71 KA01 KA04 KB05                       NA01 QB01 QB14 QB15 QB19                       QC01 RA03 RA12

Claims (4)

[Claims] 1. Diphenylmethane diisocyanate (A
1), polymethylene polyphenylene polyisocyanate (A2), tolylene diisocyanate (A3), polyisocyanate composition (A) obtained from polyol (A4), and a compound having two or more active hydrogens as an initiator, the number of carbon atoms By adding an alkylene oxide containing 50% by mass or more of an alkylene oxide of 3 or more,
Furthermore, the monool concentration obtained by adding 10 to 30% by mass of ethylene oxide to the terminal is 30 mol% or less,
A polyol composition (B) containing 40 mass% or more of a polyether polyol (a) having a number average molecular weight of 2,000 to 10,000, a catalyst (C), a foaming agent (D), a foam stabilizer (E). (A1) contains 2 to 60 mass% of isomers other than 4,4'-diphenylmethane diisocyanate, and (A1) and (A1) The ratio (mass ratio) of A2) is (A1) /
(A2) = 30/70 to 95/5, the proportion of (A3) in the polyisocyanate composition (A) is 45% by mass or less, and the apparent total density of the resulting flexible polyurethane foam is 5
0 kg / m ³ or less, impact resilience 60% or more, frequency 6
A method for producing a flexible polyurethane foam, characterized in that a vibration transmissibility at 1 Hz or higher is 1 time or less and a repeated compression set is 2% or less. 2. The proportion (mass ratio) of the polyol (A4) in the polyisocyanate composition (A) is 3 to 40 mass%.
The method for producing a flexible polyurethane foam according to claim 1, wherein 3. The polyol (A4) is obtained by adding an alkylene oxide containing 50% by mass or more of an alkylene oxide having 3 or more carbon atoms, using a compound having two or more active hydrogens as an initiator, and further adding ethylene to the terminal. Obtained by adding 10 to 30% by mass of oxide, the monool concentration is 30 mol% or less, and the number average molecular weight is 2,000.
To polyether polyol (a) and / or a compound having two or more active hydrogens as an initiator, an alkylene oxide having 50% by mass or more of ethylene oxide is added to give a number average molecular weight of 500 to 1
The method for producing a flexible polyurethane foam according to claim 1 or 2, which comprises a polyether polyol (II) having a content of 10,000. 4. The method for producing a flexible polyurethane foam according to claim 1, 2, 3 or 4, wherein the polyol composition (B) contains 1 to 20 mass% of polymer fine particles.