JPH08231677A - Preparation of high elasticity polyurethane foam - Google Patents

Abstract

PURPOSE: To improve impact resilience, durability and vibration property by allowing a specific polymer polyol to react with a polyisocyanate in the presence of a blowing agent, a foam regulator and a catalyst. CONSTITUTION: In polyoxyalkylene polyols having oxyethylene groups at the terminal and having 5-25wt.% total oxyethylene groups, (A) a polyol made, for instance, with a composite metal cyanide complex or a cesium catalyst and having a total unsaturation value of at most 0.060meg/g or a mixture of the component (A) and (B) a polyol made with a K or Na catalyst at a weight ratio of (A)/(B)=100/0-12/88 yields (C) a polyol having 3 functional groups and a hydroxyl value of 5-40 and (D) a polyol having 4-6 functional groups and a hydroxyl value of 5-45. A mixture of the (C) and the (D) mixed in the weight ratio of (C)/(D)=25/75-85/15 and having a total unsaturation value of at most 0.080meg/g is used as a polymer polyol and allowed to react with a polyisocyanate in the presence of a blowing agent, a foam regulator and a catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a highly elastic polyurethane foam, and more particularly to a method for producing a highly elastic polyurethane foam having excellent impact resilience, durability and vibration characteristics as a cushioning material.

[0002]

2. Description of the Related Art So far, flexible polyurethane foam,
In particular, high-elasticity polyurethane foam has been widely used as a cushioning material for automobiles, furniture, office equipment, etc. by taking advantage of its excellent cushioning property and high impact resilience. As its production method, polyisocyanate and a high-molecular-weight polyol having mainly 3 functional groups are reacted in the presence of a catalyst, a foaming agent, a foam stabilizer and, if necessary, a crosslinking agent, an additive, etc., and heat-cured in a mold. The method is known.

[0003]

However, in recent years, as a function of the cushioning material, a function which has been required in the past (cushioning property, mechanical strength, resistance to moist heat, etc.) is required to have a higher added value. For example, as automobiles become more sophisticated, it is required to improve the riding comfort and sitting comfort of seat cushions, and as a countermeasure against this, improvement in rebound resilience, durability performance, and vibration characteristics is desired.

Various frequency vibrations are generated in an automobile due to road irregularities, engine vibrations, etc. during traveling, and these vibrations are sometimes transmitted to the seat occupant's body by using the seat as a medium and sometimes expanding the amplitude to several times. As a result, the riding comfort and the sitting comfort are deteriorated and the seat occupant feels uncomfortable. Frequency that is said to be particularly sensitive to humans (4-8H
z, 10 to 15 Hz), the greater the amplitude of the human body of the seated person (in other words, the greater the amplitude transmissibility to the human body).
Discomfort is considered large. Therefore, lowering the vibration transmissibility of the cushion at a frequency sensitive to humans also provides excellent vibration characteristics.

Further, when the seat is seated for a long period of time, the seat gradually becomes tired, and as a result, a feeling of bottoming of the seat occurs, resulting in deterioration of riding comfort and sitting comfort, and therefore, sag resistance (durability). It is also an important issue to develop excellent seats.

However, it has been found that there is a limit to the improvement of these performances in the conventional production method using a polymer polyol mainly composed of a high-molecular-weight polyol having 3 functional groups.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the problem, the present inventors have shown that by using a specific high molecular weight polyol, excellent cushioning property, riding comfort and sitting comfort are exhibited. We have found a method for producing a highly elastic polyurethane foam with functions (high impact resilience, good vibration characteristics, and high durability). That is, the present invention is the following inventions.

In the method for producing a polyurethane foam by reacting a polyisocyanate and a polymer polyol in the presence of a foaming agent, a catalyst and a foam stabilizer, the polymer polyol has a functional group number of 3 and a hydroxyl value of 5 to 40, A polyoxyalkylene polyol (A) having an oxyethylene group at the terminal and a total oxyethylene group content of 5 to 25% by weight, and a functional group number of 4 to 6 and a hydroxyl value of 5 to 4
5, polyoxyalkylene polyol (B) having an oxyethylene group at the terminal and a total oxyethylene group content of 5 to 25% by weight (A) / (B) = 25
/ 75 to 85/15, and the polyol (A) was prepared by using a polyol (C) having a total degree of unsaturation of 0.060 meq / g or less and a polyol (C) and a sodium-based catalyst or a potassium-based catalyst. Polyol (E) which is a mixture of polyol (D) and has a total unsaturation of 0.060 meq / g or less, or polyol (E) and a polyol (F) produced with a sodium-based catalyst or a potassium-based catalyst. The method for producing a highly elastic polyurethane foam is characterized in that it is a mixture with

The contents of the present invention will be further described in detail.

Polyol (A) used in the present invention
As the compound, a compound obtained by adding an alkylene oxide described below to an active hydrogen compound having three active hydrogen atoms in the presence of a catalyst and a mixture thereof are used. As the active hydrogen compound having three active hydrogens, conventionally used alcohols, amines and the like are used.

Alcohols include glycerin, trimethylolpropane, trimethylolethane, hexanetriol and the like, and amines include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine and isopropanolamine, N- ( Heterocyclic amines such as 2-aminoethyl) piperazine are used. Two or more of these active hydrogen compounds may be used in combination, but alcohols are preferred.

The polyol (B) used in the present invention is an active hydrogen compound having 4 or more active hydrogen atoms, a mixture of these compounds, or an active hydrogen compound having 4 or more active hydrogen atoms and an active hydrogen atom. A compound obtained by adding an alkylene oxide described below to a mixture of active hydrogen compounds having a number of 3 or less and an average number of functional groups of 4 to 6 in the presence of a catalyst, and a mixture thereof are used.

As the active hydrogen compound, ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, neopentyl glycol,
1,4-butanediol, 1,6-hexanediol,
Polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, diglycerin, meso-erythritol, methylglucoside, glucose, sorbitol, sucrose, ethylenediamine, diethylenetriamine, tolylenediamine, diaminodiphenylmethane, hexamethylenediamine, propylenediamine, etc. The condensation system of amine compounds, phenolic resins, novolac resins and the like are used. Two or more of these active hydrogen compounds may be used in combination, but polyhydric alcohols are preferred.

As the alkylene oxide to be added to the active hydrogen compound, there are ethylene oxide, propylene oxide, butylene oxide, styrene oxide and the like, and the combination of ethylene oxide and propylene oxide is the best. It is essential that the high molecular weight polyol of the present invention has a block structure of an oxyethylene group at the molecular end, but it is also possible to have a random addition structure of ethylene oxide in the molecular chain. This can be obtained by adding alkylene oxide having 3 or more carbon atoms and ethylene oxide to the active hydrogen compound sequentially or by mixing, and finally adding ethylene oxide.

The hydroxyl value of the polyol (A) used in the present invention is 5 to 40, preferably 10 to 38. The content of all oxyethylene groups in the polyol (A) is 5 to 25.
%, Preferably 8 to 20% by weight. When the content of total oxyethylene groups is less than 5% by weight, foam collapses and insufficient curing occurs during foam molding, and when it exceeds 25% by weight, the number of closed cells increases and the shrinkage of the foam becomes remarkable, and at the same time the wet heat compression is performed. The distortion gets worse.

Polyol (B) used in the present invention
Has a hydroxyl value of 5 to 45, preferably a hydroxyl value of 10 to 40. The content of all oxyethylene groups in the polyol (B) is 5 to 25% by weight, preferably 8 to 20% by weight.

When the total oxyethylene group content is 5% by weight, foam collapse and insufficient curing occur during foam molding, and when it exceeds 25% by weight, the number of closed cells increases and foam shrinkage becomes remarkable.

Further, the polyol (A) has a total unsaturation of 0.
A polyol (C) of 060 meq / g or less or a mixture of the polyol (C) and a polyol (D) produced with a sodium-based catalyst or a potassium-based catalyst, and the polyol (B) has a total degree of unsaturation of 0.060 meq / g. The present invention is characterized by being the following polyol (E) or a mixture of the polyol (E) and a polyol (F) produced with a sodium catalyst or a potassium catalyst. Due to this, the high-elasticity polyurethane foam of the present invention exhibits excellent impact resilience, durability and vibration characteristics.

The weight ratio of the polyol (C) to the polyol (D) is (C) / (D) = 100/0 to 12/8.
It is preferably 8.

The weight ratio of the polyol (E) to the polyol (F) is (E) / (F) = 100/0 to 12/8.
It is preferably 8.

When the polyol (A) is a mixture of the polyol (C) and the polyol (D), and / or the polyol (B) is the polyol (E) and the polyol (F).
In the case of a mixture of the above, the total degree of unsaturation of the high molecular weight polyol is preferably 0.080 meq / g or less.

The polyol (C) and the polyol (E) are
The polyol has a total unsaturation of 0.060 meq / g or less, and is preferably a high molecular weight polyol produced by using a complex metal cyanide complex catalyst or a cesium catalyst.

It is also preferable that the high molecular weight polyol in the present invention is a polymer-dispersed polyol containing a polymer obtained by polymerizing a vinyl monomer. Examples of vinyl monomers include the following.

(1) Acrylic acid, methacrylic acid and derivatives thereof: acrylonitrile, methacrylonitrile,
Acrylic acid, methacrylic acid and salts thereof, methyl methacrylate, acrylic acid amide, methacrylic acid amide, etc. (2) Aromatic vinyl monomers: styrene, α-methylstyrene, α-ethylstyrene, etc. (3) Olefin hydrocarbon monomer: ethylene, propylene, butadiene, isobutylene, etc. (4) Vinyl ester monomer: vinyl acetate, etc. (5) Vinyl halide monomer: vinyl chloride, vinylidene chloride, etc. (6) Vinyl ether monomer: Vinyl methyl ether etc.

Of these, preferred vinyl monomers are acrylonitrile, methyl methacrylate, styrene, and butadiene, and particularly preferred are acrylonitrile, styrene, and a combination system of acrylonitrile and styrene.

The vinyl-based monomer used for the modification can be used in various proportions, but is generally used in an amount of 2 with respect to the polyol (A) or (B) or the mixture of (A) and (B).
˜75 wt%, preferably 2-50 wt%. In the present invention, the polymer-dispersed polyol can be produced by a known method, for example, a method of polymerizing a vinyl-based monomer in the presence of a polymerization catalyst in a high-molecular weight polyol, or mixing separately produced polymer fine particles with the high-molecular weight polyol. And a method of polymerizing a macromonomer having a vinyl unsaturated group and a vinyl monomer in a high molecular weight polyol.

Polyisocyanate used in the present invention
The compound used heretofore can be used. As such a polyisocyanate, various compounds having two or more isocyanate groups can be used,
Aromatic polyisocyanates are particularly suitable. As the aromatic polyisocyanate, a mononuclear or polynuclear compound having an isocyanate group bonded to an aromatic nucleus or a modified product thereof is suitable. Specific examples include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, and prepolymer type, carbodiimide type, urea type and other modified products thereof. Two or more of these polyisocyanate compounds can be used in combination.

The amount of polyisocyanate used is expressed as 100 times the number of isocyanate groups with respect to the number of active hydrogens of all active hydrogen-containing compounds (usually the value expressed by 100 times is called the isocyanate index) 80-120.
It is preferably 85 to 110.

As the catalyst used in the present invention, a catalyst generally used in a polyurethane reaction can be used. They are amine catalysts, organometallic catalysts, a combination system of both catalysts, and the like. Examples of amine-based catalysts include triethylenediamine, N-methylmorpholine, N-ethylmorpholine, triethylamine, tetramethylhexamethylenediamine, bis- (dimethylaminoethyl) ether, and examples of organometallic catalysts include tin-based stannas. Examples include octoate, stanaus laurate, dibutyltin laurate, and lead-based octylic acid. The amount of the catalyst used should vary depending on the desired reactivity, but it is usually 0.005 to 4% by weight based on the reaction mixture.

As the foaming agent, molding with water alone is sufficient, but 1,1-dichloro-2,2,2-trifluoroethane and 1,1-dichloro-2,2,2-trifluoro are available. It is also possible to use ethane, methylene chloride and the like together.

The foam stabilizer is a siloxane-based foam stabilizer, and examples thereof include polydialkyl siloxane and polydialkyl siloxane-polyoxyalkylene brog copolymer.

[0032]

EXAMPLES The present invention will be described below with reference to Examples (Examples 1 to 12 and 22).
~ 33) and comparative examples (Examples 13 to 21, Examples 34 to 42).
However, the present invention is not limited thereto.

The high molecular weight polyols used are shown in Table 1 and other raw materials are shown below. In the table, 1EO group indicates an oxyethylene group. Parts indicate parts by weight.

Polymer-dispersed polyol (represented by POP in the table) (I): 100 parts of high molecular weight polyol (1), 13 parts of acrylonitrile and 16 parts of styrene were added to initiate azobisisobutyronitrile at a temperature of 120 ° C. Polymer-dispersed polyol having a hydroxyl value of 23 (mgKOH / g) reacted as an eater.

Polymer-dispersed polyol (II): 100 parts of high molecular weight polyol (7), 13 parts of acrylonitrile and 16 parts of styrene were reacted at a temperature of 120 ° C. with azobisisobutyronitrile as an initiator to give a hydroxyl value of 23. (MgKOH / g) polymer-dispersed polyol.

Polymer-dispersed polyol (III): 100 parts of high molecular weight polyol (5) and acrylonitrile 13
Parts and 16 parts of styrene were reacted at a temperature of 120 ° C. with azobisisobutynitrile as an initiator to obtain a polymer-dispersed polyol having a hydroxyl value of 16.4 (mgKOH / g).

The additives are shown in Table 2.

[Foaming Conditions] Table 3 shows the foaming conditions.

[Method for measuring physical properties of polyurethane foam] The methods for measuring physical properties are JIS-K-6401 and JIS-K.
-Total density (unit: kg / m based on 6301 method)
³ ), 25% hardness (kg / 314 cm ² ), compression set (unit:%), wet heat compression set (unit:%), impact resilience (unit:%), and tensile elongation (unit:%) Was measured.

[Measurement Method of Durability] Polyurethane foam molded with the above mold is 300 × mm × 300 mm × 1
After cutting to 00 mm and measuring 25% hardness,
This foam was subjected to 100,000 repeated compression of 50% over the entire surface, and then allowed to stand for 30 minutes with no load, and the 25% hardness was measured again. Decrease rate of 25% hardness (hardness reduction rate, unit:
%) Was taken as the durability evaluation item.

[Evaluation of Vibration Characteristics] A 400 kg × 100 T test piece was loaded with a 50 kg load Tekken plate, and the oscillating table was oscillated with an amplitude of ± 2.5 m / m from 1 Hz to 10 Hz. The amplitude of the plate is measured and the resonance frequency (unit:
%), And a transmissibility of 6 Hz was obtained.

Examples 1 to 21 Polyol (C) constituting polyol (A), polyol (D) and polyol (E) constituting polyol (B), polyol (F) and polymer dispersed polyol are shown in Table 4. The catalyst (I) is added in an amount of 0.38 with respect to 100 parts of the mixture mixed at a ratio of 6
Parts, catalyst (II) 0.06 parts, foam stabilizer (I) 1.0
Parts, 2.5 parts of diethanolamine as a cross-linking agent, and 3.0 parts of water as a foaming agent were mixed. Isocyanate (I) was added to this mixture so that the isocyanate index was 105, and hand foaming was carried out according to the method of [foaming conditions] to evaluate the performance of the resulting foam (Tables 4 to 6).

Examples 22 to 42 Polyol (C) constituting polyol (A), polyol (D) and polyol (E) constituting polyol (B), polyol (F) and polymer-dispersed polyol are shown in Table 6. Catalyst (I) 0.38 per 100 parts of the mixture at a ratio of
Parts, 0.06 parts of catalyst (II), 1.0 of foam stabilizer (II)
Parts and water as a foaming agent were mixed in a ratio of 3.3 parts. Isocyanate (II) was added to this mixture so that the isocyanate index was 97, and hand foaming was carried out according to the method of [foaming conditions] to evaluate the performance of the resulting foam (Tables 6 to 8).

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

[Table 6]

[0050]

[Table 7]

[0051]

[Table 8]

[0052]

INDUSTRIAL APPLICABILITY The present invention exhibits excellent effects on impact resilience, durability and vibration characteristics.

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Claims (7)

[Claims] 1. A method for producing a polyurethane foam by reacting a polyisocyanate and a polymer polyol in the presence of a foaming agent, a catalyst and a foam stabilizer, wherein the polymer polyol has a functional group number of 3 and a hydroxyl value of 5 to 5. 40, a polyoxyalkylene polyol (A) having an oxyethylene group at the terminal and a total oxyethylene group content of 5 to 25% by weight, and a functional group number of 4 to 6 and a hydroxyl value of 5 to 4
5, polyoxyalkylene polyol (B) having an oxyethylene group at the terminal and a total oxyethylene group content of 5 to 25% by weight (A) / (B) = 25
/ 75 to 85/15, and the polyol (A) has a total degree of unsaturation of 0.060 meq / g.
The following polyol (C) or a mixture of the polyol (C) and a polyol (D) produced with a sodium-based catalyst or a potassium-based catalyst, and the polyol (B) has a total unsaturation of 0.060 meq / g or less. (E)
Alternatively, it is a mixture of the polyol (E) and the polyol (F) produced with a sodium-based catalyst or a potassium-based catalyst, and a method for producing a highly elastic polyurethane foam. 2. The weight ratio of the polyol (C) to the polyol (D) is (C) / (D) = 100/0 to 12/8.
The manufacturing method according to claim 1, which is 8. 3. The weight ratio of the polyol (E) to the polyol (F) is (E) / (F) = 100/0 to 12/8.
The manufacturing method according to claim 1, which is 8. 4. The total unsaturation of the polymer polyol is 0.0
The production method according to claim 1, which is 80 meq / g or less. 5. The polyol (C) and the polyol (E) are
The production method according to claim 1, which is a high-molecular-weight polyol produced by using a complex metal cyanide complex catalyst or a cesium-based catalyst. 6. The method according to claim 1, wherein the high molecular weight polyol is a polymer-dispersed polyol containing a polymer obtained by polymerizing a vinyl monomer. 7. The method according to claim 1, wherein the foaming agent is at least one foaming agent selected from water and an inert gas.