JP6635711B2 - Flexible polyurethane foam with excellent compression set, vibration damping and compression creep - Google Patents

Description

  The present invention relates to a flexible polyurethane foam having excellent compression set, vibration damping properties and compression creep properties.

Conventionally, there have been known vibration-damping materials, vibration-damping materials, shock-absorbing materials and the like utilizing a soft polyurethane foam having a low rubber hardness and utilizing these vibration-damping and shock-absorbing properties (Patent Documents 1 and 2).
However, foams have the advantage of weight reduction, but on the other hand, when the rubber hardness is reduced, the compression set and compression creep characteristics are further reduced as compared with the case where the rubber hardness of the non-foamed material is lowered. there were.

  By the way, a flexible polyurethane foam having a rubber hardness of 50 or less and having excellent compression set, vibration damping properties and compression creep properties has not been proposed so far, and a highly functionalized elastomer has been proposed. The appearance of these flexible polyurethane foams has been strongly expected from various industrial fields as a material for replacing rubber, a new material for cushioning, and the like.

JP 2009-280658 A JP 2012-137609 A

Conventionally, it has been known that a polyurethane foam used as an anti-vibration member deforms when subjected to a load, and the amount of deformation increases with time.
Therefore, an object of the present invention is to find that it is extremely convenient as a buffer material if a flexible polyurethane foam having excellent compression set, vibration damping properties and compression creep properties is used in a place where it is used under a load for a long time. The object of the present invention is to provide a flexible polyurethane foam having excellent compression set, vibration damping properties and compression creep properties.
Further, another object of the present invention is to solve the conventional problems, have the same vibration damping properties as conventional products while having a rubber hardness of 50 or less, and have excellent compression set and compression creep properties. It is to provide a flexible polyurethane foam.

The present inventors have conducted intensive studies in view of the above points, and found that urethane foam obtained by reacting a specific polyol with diphenylmethane diisocyanate or a derivative thereof has a low rubber hardness of 50 or less and excellent vibration damping properties. The present invention was also found to be a flexible polyurethane foam excellent in compression set and compression creep. That is,
(1) The flexible polyurethane foam of the present invention comprises:
A compression set of 10% or less and a vibration damping property (tan δ measured by a dynamic bending test) produced from a composition obtained by reacting the following (A) polyol component, (B) polyisocyanate component, and (C) water. ) Is a flexible polyurethane foam having a compression creep property of not less than 0.2 and less than 20%,
(A) a polyol component,
(A-1) a polyol having a functional hydroxyl number of 2.0 to 3.0 and a hydroxyl value of 20 to 170 and having an active hydroxyl group at a terminal,
(A-2) 4 to 8 parts by mass of a hyperbranched polymer having 4 or more functional groups and a hydroxyl value of 380 or more and having an active hydroxyl group at a terminal;
(A-3) a mixture of 3 to 5 parts by mass of a low molecular polyol having a functional group number of 2.0 to 3.0 and a hydroxyl value of 900 to 2000,
(B) the polyisocyanate component is diphenylmethane diisocyanate or a derivative thereof,
(C) water,
(A) The equivalent ratio of the isocyanate group (NCO group) of the prepolymer to the hydroxyl group (OH) of the polyol component + (C) water (NCO / OH ratio) is 1.00 to 1.10.
(2) The flexible polyurethane foam of the present invention is characterized in that in the above (1),
(A-2) The hyperbranched polymer having an active hydroxyl group at a terminal,
It is a compound obtained by self-condensation of dimethylol fatty acid .
(3) The flexible polyurethane foam according to (1) or (2) above, wherein (A-2) the hyper-branched polymer having an active hydroxyl group at a terminal,
A compound obtained by reacting 1 mol of diisocyanate with 2 mol of triol .
(4) In the flexible polyurethane foam of the present invention, in any one of the above (1) to (3), the derivative of diphenyl-methane-diisocyanate (MDI) of the polyisocyanate component (B) is a polytetramethylene ether glycol . It is a prepolymer having an active isocyanate group at a terminal obtained from a reaction with a polyisocyanate compound.

The flexible polyurethane foam of the present invention is deformed according to the elastic modulus when subjected to a load, but has a small increase in the amount of deformation over time, and is excellent in compression set, vibration damping properties and compression creep properties.
When used in a place where a load is used for a long time and used, it is excellent as a cushioning member, and can be used as a shock absorbing member, a vibration isolating member, and the like.

  Further, for example, in a two-story or more house, if the flexible polyurethane foam of the present invention is placed as a cushioning material between above a beam supporting a floor and below the floor, floor vibration and impact to the floor can be suppressed, thereby reducing noise. Excellent effect as a suppressing member.

In order to achieve the above-mentioned object, the flexible polyurethane foam of the present invention comprises:
It is characterized by having excellent compression set, vibration damping properties and compression creep properties composed of a polyurethane foam obtained by reacting (A) a polyol component, (B) a polyisocyanate component and (C) water.
Here, the (A) polyol component is
(A-1) a polyol having a functional hydroxyl number of 2.0 to 3.0 and a hydroxyl value of 20 to 170 and having an active hydroxyl group at a terminal,
(A-2) a hyper-branched polymer having 4 or more functional groups, a hydroxyl value of 380 or more, and having an active hydroxyl group at a terminal;
(A-3) a mixture of a low-molecular polyol having a functional group number of 2.0 to 3.0 and a hydroxyl value of 900 to 2,000,
(B) the polyisocyanate component is diphenyl-methane-diisocyanate or a derivative thereof,
(C) water.

<(A-1) Polyol>
The polyol (A-1) of the polyol component (A-1) used in the present invention is responsible for the main component of the polyol component, and has a functional group number of 2.0 to 3.0 and a hydroxyl value of 20 to 170, It is necessary to have an active hydroxyl group at the terminal.
When the number of functional groups is less than 2, compression strain and compression creep tend to deteriorate, and when the number of functional groups is more than 3, rubber hardness is more than 50, which is not preferable.
When the hydroxyl value is less than 20, the compression set becomes large, which is not preferable. When the hydroxyl value is more than 170, the rubber hardness becomes more than 50, which is not preferable.
The kind of the terminal of the polyol is not particularly limited, but it is preferable that the polyol has at least partially a primary hydroxyl group or a primary hydroxyl group in order to surely form polyurethane.

  In order to achieve the above-mentioned object, specific examples of the polyol (A-1) used in the present embodiment include polytetramethylene from the viewpoint of liquid viscosity, price, ease of adjusting the hydroxyl value and the number of functional groups, and the like. Glycols and polyether polyols are preferred.

The polytetramethylene glycol is a known polyol obtained by ring-opening polymerization of tetrahydrofuran, and examples thereof include PTMG (manufactured by Mitsubishi Chemical) and PTG (manufactured by Hodogaya Chemical).
As the polyether polyol, a known compound obtained by ring-opening addition polymerization of an alkylene oxide using a low molecular weight active hydrogen compound as an initiator can be used.

  As a typical example of the polyether polyol, a polyol in which an acrylic polymer or a styrene polymer is blended can be preferably used in addition to the polyether polyol using the above initiator.

  Specific trade names of the above polyether polyols include, for example, trade names Exenol (manufactured by Asahi Glass Co., Ltd.) and Sunflex (Sanyo Chemical Industries). Also, a mixture of two or more of these can be used.

  As long as there is no problem, known castor oil-based polyols, ε-caprolactone-based polyols, β-methyl-δ-valerolactone-based polyols, carbonate-based polyols, and the like may be used, and two or more of these may be used in combination. Can also.

<(A-2) Hyper-branch polymer>
The (A-2) hyper-branched polymer (HBP) used in the present invention is a hyper-branched polymer (multi-branched polymer) having an active hydroxyl group at a terminal and having 4 or more functional groups and 380 or more hydroxyl value. It is necessary to have an active hydroxyl group at the terminal.
When the number of functional groups is less than 4, compression strain and compression creep tend to deteriorate, and when the hydroxyl value is less than 380, compression strain and compression creep tend to deteriorate.
The hyper-branched polymer (multi-branched polymer) of the present invention can be a compound obtained by self-condensation of dimethanol fatty acid as a polycondensation system of an AB _2- type monomer.
Examples of the polyaddition system of the A ₂ B ₃ type monomer include compounds obtained by polyaddition of diisocyanate and triol.
A polycondensation-type or polyaddition-type hyperbranched polymer (HBP) is synthesized in one step by selecting an appropriate monomer, and becomes a compound having a spherical-like molecular shape without intramolecular pores (see the following references). 1, 2).
(Reference 1: Yang, G; M. Macromolecules, 32, 2215 (1999))
(Reference 1: Yang, G; M. Macromolecules, 32, 2215 (1999)) (Reference 2: Jikei, M .; Chon, S .; Kakimoto, M .; Kawauchi, S .; Imase, T .; Watanabe, J .; Macromolecules, 32, 2061 (1999))

A hyperbranched polymer (HBP) of the AB type ₂ monomer having an active hydroxyl group at the terminal of the polycondensation system (expressed as AB ₂ HBP) is a dimethanol fatty acid such as dimethanolpropionic acid or dimethanolbutane. It is a compound obtained by self-condensation of acid or the like.
As a specific trade name of the hyperbranched polymer (HBP), for example, Boltorn H311, P500 (manufactured by Perstorp) can be mentioned.

The hyperbranched polymer (HBP) having an active hydroxyl group at the terminal of the polyaddition system of the A ₂ B ₃ type monomer (referred to as A ₂ B ₃ HBP) is a diisocyanate {({2 ⁿ ) -1} (where n = 1, 2, 3 ... the same applies hereinafter) and triol (Σ2 ⁿ ) (where n = 1, 2, 3 ... the same applies hereinafter) mole.
In this synthesis, 100 parts by mass of toluene or methyl ethyl ketone as a solvent was charged into 100 parts by mass of a total amount of diisocyanate {({2 ⁿ ) -1} mol and triol ({2 ⁿ ) mol), and the mixture was slowly refluxed at room temperature for 4 hours. The reaction was allowed to proceed, and then 0.0025 parts by mass of dibutyl-tin-laurate was charged to the reaction tank as a catalyst, and refluxed at 80 ° C for 4 hours. After that, the reaction solution was desolvated under vacuum at 80 ° C using an evaporator. It is obtained by doing.

[Synthesis of polyaddition type hyperbranched polymer (HBP) of A ₂ B ₃ type monomer]
Under a nitrogen gas atmosphere, 500 g of methyl ethyl ketone (MEK) was charged into a four-neck separable flask equipped with a heating device provided with a stirring blade, a reflux device, and a thermometer, and then 577 g (2.6 mol) of isophorone-diisocyanate was charged. .
Next, a solution of 423 g (5.2 mol) of glycerin and 500 g of MEK was dropped at room temperature with stirring and reacted for 4 hours while maintaining the temperature of the reaction solution at 40 ° C. or lower.
Next, 0.025 parts by mass of dibutyl-tin-laurate as a reaction catalyst was charged into the reaction tank, and refluxed at 80 ° C for 4 hours.
After completion of the reaction, the reaction solution was put into an eggplant-shaped flask, and then de-MEK was performed at 80 ° C. under vacuum using an evaporator. The obtained HBP has a viscosity of 56 Pa. The liquid was a viscous liquid having the number of functional groups of 4, and the hydroxyl value was 382.

<(A-3) Low molecular polyol>
The (A-3) low molecular polyol used in the present invention is a low molecular polyol having a functional group number of 2.0 to 3.0 and a hydroxyl value of 900 to 2,000. When the number of functional groups is less than 2, compression strain and compression creep tend to deteriorate, and when the number of functional groups is more than 3, rubber hardness is more than 50, which is not preferable. A low-molecular polyol having a compression creep that tends to deteriorate and a hydroxyl value of more than 2,000 is not preferable because it has no versatility and is expensive.

<Mixing ratio>
In the flexible polyurethane foam of the present invention,
(A) a polyol component constituting (A-1) a polyol having a functional group number of 2.0 to 3.0 and a hydroxyl value of 20 to 170, having an active hydroxyl group at a terminal;
(A-2) a hyperbranched polymer (HBP) having 4 or more functional groups and a hydroxyl value of 380 or more and having an active hydroxyl group at a terminal;
(A-3) a low molecular polyol having a functional group number of 2.0 to 3.0 and a hydroxyl value of 900 to 2,000,
Is preferably as follows.
That is,
When the total amount of (A-1) polyol, (A-2) hyperbranched polymer (HBP), and (A-3) low molecular polyol is 100 parts by mass,
The ratio of (A-1) polyol / (A-2) hyperbranched polymer (HBP) / (A-3) low molecular polyol is preferably 87/8/5 to 93/4/3.
More preferably, it is set to 89/7/4 to 92/5/3.
When the proportion of (A-2) hyper-branched polymer (HBP) exceeds 8 in this mixing ratio, the rubber hardness is higher than 50, and is not preferable. And no effect on compression creep deformation.
When the proportion of the low molecular polyol (A-3) exceeds 5 in the mixing ratio, the rubber hardness becomes higher than 50. When the proportion is less than 3, the compression set and the compression creep deformation are reduced. No effect on quantity.
Therefore, of the total amount of 100 parts by mass,
(A-2) The ratio of the hyperbranched polymer (HBP) is preferably between 4 and 8 parts by mass,
(A-3) The ratio of the low-molecular polyol is preferably between 3 and 5 parts by mass,
(A-1) The polyol is adjusted as the remaining amount.

<(B) polyisocyanate component>
Examples of the (B) polyisocyanate component include diphenyl-methane-diisocyanate (MDI), partially modified carbodiimide MDI (liquid MDI), and derivatives of MDI or liquid MDI.

Here, derivatives of MDI or liquid MDI (these are referred to as prepolymers in the present specification) can be obtained as a compound having a terminal isocyanate residue by a known method shown below.
This prepolymer is not an essential component in the present invention,
(A) It is preferably added to improve compatibility with the polyol component and facilitate mixing with other components.
The derivative (prepolymer) of MDI or liquid MDI used in the present invention is:
A polyether polyol having a functional group number of 2.0 to 3.0 less than the theoretical amount is reacted with a polyisocyanate compound using a known technique, and the remaining amount of active isocyanate groups (NCO groups) at the terminals is 10 to 23% by mass. , Preferably 15 to 18% by mass.
When the remaining amount of the active isocyanate group (NCO group) exceeds 23% by mass, there is no effect of using the prepolymer, and when the remaining amount of the active isocyanate group (NCO group) is less than 10% by mass, the prepolymer Has a high viscosity, which hinders the production of flexible polyurethane foam.

  As the polyisocyanate component (B), isophorone diisocyanate, tolylene diisocyanate, cyclohexyl diisocyanate, hexamethylene diisocyanate, xylidene diisocyanate, or the like may be used as long as there is no problem. You can also.

In the present invention, the reaction ratio when reacting (A) a polyol component, (B) a polyisocyanate component and (C) water is as follows:
(A) The equivalent ratio of the isocyanate group (NCO group) of the prepolymer to the hydroxyl group (OH) of the polyol component + (C) water, that is, the NCO / OH ratio (INDEX) is 1.00 to 1.10, preferably 1. 03 to 1.05.
When the equivalent ratio exceeds 1.10, the stability of the hardness of the flexible urethane foam with time is not preferable, and when it is less than 1.00, the compression set and the compression creep deformation increase. Not preferred.
The smaller the equivalent ratio, the lower the hardness of the obtained flexible polyurethane foam.

Here, in performing the urethanization reaction between the (B) polyisocyanate component, (A) polyol component, and (C) water, an appropriate urethanization catalyst can be used. As the urethanization catalyst, a known catalyst such as a tertiary amine compound or an organometallic compound can be used. For example, triethylenediamine, N, N-dimethylhexamethylenediamine, N, N-dimethylbutanediamine, diazabicyclo (5,4,0) undecene-7 (DBU) and DBU salt, bismuth tris (2-ethylhexanoate) , Diisopropoxybis (ethylacetoacetate) titanium, lead octylate, dibutyltin laurate and the like are preferred.
However, the use of this urethanization catalyst is not an essential requirement of the present invention.

Here, in reacting the (A) polyol component, (B) polyisocyanate component, and (C) water, an appropriate foam stabilizer can be used. For example, organopolysiloxane, alkyl carboxylate, alkyl benzene sulfonate and the like can be mentioned.
The compounding amount of the foam stabilizer is 0 to 5 parts by mass, preferably 1 to 2 parts by mass, based on 100 parts by mass of the total polyol.

  In addition, in order to improve the durability and stability of the flexible polyurethane foam member, heat stabilizers, antioxidants, ultraviolet absorbers, ultraviolet stabilizers, fillers, etc. are used as stabilizers as long as there is no problem. One type or a mixture of two or more types can be used. Further, in addition to those described above, pigments, dyes, flame retardants, plasticizers, dispersants, surface modifiers, and the like can be appropriately added.

The (A) polyol component, (B) polyisocyanate component, and (C) water used as the raw materials are mixed at room temperature or in a heated state, respectively. Here, (C) water may be previously mixed with the polyol, or added at the time of mixing the main component.
When the additives are mixed, they may be mixed in advance with the polyol component (A) or may be added when the main components are mixed.

After thoroughly mixing the above-mentioned components, 205 g to 210 g is poured into a 220 mm × 220 mm × 10 mm thick mold heated to room temperature to 100 ° C., and a lid is placed. The urethane reaction is performed at room temperature to 100 ° C. for 15 minutes. Wake up.
Thereafter, the flexible polyurethane foam member can be obtained by taking out of the mold and preliminarily reacting for 2 hours.

Hereinafter, in order to explain the present invention in more detail, Examples 1 to 16 and Comparative Examples 1 to 13 are shown in the table.
(A) The following materials were prepared as a polyol component.
(A-1) Polyol <Polyol 1>
Polyoxypolypropylene (terminal ethylene) triol (functional group number 3, hydroxyl value 17, average molecular weight 10,000)
<Polyol 2>
Mixture of polyoxypolypropylene (terminated ethylene) triol and acrylic resin (number of functional groups: 3, average hydroxyl value: 21, average molecular weight: 8,000)
<Polyol 3>
Polytetramethylene ether glycol (functional group number 2, hydroxyl value 110, average molecular weight 1,000)
<Polyol 4>
Polyoxypolypropylene (terminal ethylene) triol (functional group number 3, average hydroxyl value 160, average molecular weight 1,000)
<Polyol 5>
Polytetramethylene ether glycol (functional group number 2, hydroxyl value 173, average molecular weight 650)
<Polyol 6>
Mixture of polyoxypolypropylene (terminal ethylene) tetraol and acrylic resin (functional group number 4, average hydroxyl value 24, average molecular weight 8,000)

(A-2) Hyper-branched polymer <Polyol 7>
Triethanolamine-based (terminal propylene) triol (functional group number 3, average hydroxyl value 360, average molecular weight 468)
<Polyol 8>
Sorbitol-based (terminal propylene) hexaol (functional group number 6, average hydroxyl value 550, average molecular weight 612)
<Polyol 9 (AB ₂ HBP)>
Hyperbranched polymer which is a self-condensate of dimethanol-propionic acid having an active hydrogen group at the terminal (number of functional groups: 16, hydroxyl value: 600, average molecular weight: 1,500)
<Polyol 10 (A ₂ B ₃ HBP)>
Hyperbranched polymer which is a polyadduct of isophorone diisocyanate having an active hydrogen group at the end and glycerin (functional number: 4, hydroxyl value: 382, average molecular weight: 580)
<Polyol 11>
Polyoxypolypropylene (terminal ethylene) triol (functional group number 3, hydroxyl value 400, average molecular weight 420)

(A-3) Low molecular polyol <Polyol 12>
Dipropylene glycol (functional group 2, hydroxyl value 837, average molecular weight 134)
<Polyol 13>
Methylpentanediol (functional group number 2, hydroxyl value 951, average molecular weight 118)
<Polyol 14>
1,4-butanediol (functional group 2, hydroxyl value 1,245, average molecular weight 90)
<Polyol 15>
Ethylene glycol (functional group 2, hydroxyl value 1,808, average molecular weight 62)

The isocyanates 1 to 4 used as the polyisocyanate component (B) are described below.
<Isocyanate 1>
Urethane-modified MDI (NCO mass%: 22.5 to 23.5)
<Isocyanate 2>
Prepolymer obtained by reacting monomeric MDI (NCO mass%: 33.1) having 2 functional groups with polytetramethylene ether glycol (hydroxyl value 110) (terminal active isocyanate group remaining amount 18 mass%)
<Isocyanate 3>
Prepolymer obtained by reacting monomeric MDI (NCO mass%: 33.1) having 2 functional groups with polytetramethylene ether glycol (hydroxyl value 110) (remaining amount of terminally active isocyanate group: 10 mass%)
<Isocyanate 4>
Prepolymer obtained by reacting monomeric MDI (NCO mass%: 33.1) having 2 functional groups with polytetramethylene ether glycol (hydroxyl value: 110) (remaining amount of terminally active isocyanate group: 23 mass%)

<C> Pure water was used as water.
The following materials were added as other materials.
<Antioxidant>
Pentaerythrityl-tetrakis <3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate <ultraviolet absorber>
2- (2'-hydroxy-3 ', 5'-ditert-amylphenylbenzotriazole <catalyst>
Triethyldiamine <foam stabilizer>
Block copolymer of dimethylpolysiloxane and polyether

[Example 1]
(A-1) As a polyol component, a polyol 2 having a functional group number of 3, a hydroxyl value of 21, and having an active hydroxyl group at a terminal was used.
The hydroxyl value of the polyol 2 was set to a value 21 close to the lower limit 20.
[Example 2]
(A-1) As the polyol component, a polyol 3 having 2 functional groups and a hydroxyl value of 110 and having an active hydroxyl group at a terminal was used.
The hydroxyl value of the polyol 3 was set to a value 110 close to the intermediate value.
[Example 3]
(A-1) As the polyol component, a polyol 4 having a functional group number of 3 and a hydroxyl value of 160 and having an active hydroxyl group at a terminal was used.
The hydroxyl value of the polyol 4 was set to a value 160 close to the upper limit value 170.

[Comparative Example 1]
(A-1) As the polyol component, polyol 1 having a functional group number of 3 and a hydroxyl value of 17 and having an active hydroxyl group at a terminal was used.
The hydroxyl value of the polyol 1 was set to 17, which was lower than the lower limit value of 20.
[Comparative Example 2]
(A-1) As a polyol component, a polyol 5 having 2 functional groups and a hydroxyl value of 173 and having an active hydroxyl group at a terminal was used.
The hydroxyl value of polyol 5 was 173, which exceeded the upper limit of 170.
[Comparative Example 3]
(A-1) As the polyol component, a polyol 6 having 4 functional groups and a hydroxyl value of 24 and having an active hydroxyl group at the terminal was used.
The number of functional groups of the polyol 6 was set to 4, which exceeded the upper limit of 3.
In Examples 1 to 3 and Comparative Examples 1 to 3 shown in Table 1,
(A-2) Polyols 8, 9 as hyper-branched polymers,
(A-3) polyols 13 and 14 as low molecular polyols,
(B) Although it is possible to use isocyanate 1 as a polyisocyanate component, in Examples and Comparative Examples, (A-2) polyol 10 is used as a hyperbranched polymer.
(A-3) Polyol 15 as a low-molecular polyol,
(B) Isocyanate 2 was used as a polyisocyanate component.

[Example 4]
(A-2) As the hyperbranched polymer, a polyol 8 having a functional group number of 6 and a hydroxyl value of 545 and having an active hydroxyl group at a terminal was used.
[Example 5]
(A-2) As the hyperbranched polymer, polyol 9 having a functional group number of 16 and a hydroxyl value of 500 and having an active hydroxyl group at a terminal was used.
[Example 6]
(A-2) As the hyperbranched polymer, a polyol 10 having 4 functional groups and a hydroxyl value of 382 and having an active hydroxyl group at a terminal and having a mixing ratio of 4 parts by mass (lower limit) was used.
Polyol 10 had a lower limit of 4 among the mixing ratios of 4 to 8 of (A-2) hyperbranched polymer in the (A) polyol component.
[Example 7]
(A-2) As the hyper-branched polymer, a polyol 10 having 4 functional groups and a hydroxyl value of 382 and having an active hydroxyl group at a terminal and having a mixing ratio of 8 parts by mass (upper limit) was used.
The upper limit of the polyol 10 was 8 among the mixing ratios 4 to 8 of the hyperbranched polymer (A-2) in the polyol component (A).

[Comparative Example 4]
(A-2) As the hyper-branched polymer, polyol 7 having 4 functional groups and a hydroxyl value of 300 and having an active hydroxyl group at a terminal was used.
The polyol 7 was set to 300, which was lower than the lower limit of the hydroxyl value of 380.
[Comparative Example 5]
(A-2) As the hyperbranched polymer, a polyol 11 having 3 functional groups and a hydroxyl value of 400 and having an active hydroxyl group at a terminal was used.
The polyol 11 was set to 3, which was lower than the lower limit value 4 of the number of functional groups.
[Comparative Example 6]
(A-2) As the hyperbranched polymer, a polyol 10 having a functional group number of 4 and a hydroxyl value of 382 and having an active hydroxyl group at a terminal was used.
The mixing ratio of the polyol 10 was set to a ratio 3 which was lower than the lower limit value among the mixing ratios 4 to 8 of the (A-2) hyperbranched polymer in the (A) polyol component.
[Comparative Example 7]
(A-2) As the hyperbranched polymer, a polyol 10 having a functional group number of 4 and a hydroxyl value of 382 and having an active hydroxyl group at a terminal was used.
The mixing ratio of the polyol 10 was set to a ratio 9 exceeding the upper limit of the mixing ratios 4 to 8 of the hyperbranched polymer (A-2) in the polyol component (A).
In Examples 4 to 7 and Comparative Examples 4 to 7,
(A-1) The polyol component uses polyol 3,
(A-3) The polyol component uses polyol 15,
(B) Isocyanate 2 was used as the polyisocyanate component.

Example 8
(A-3) As a low molecular weight polyol component, 3.5 parts by mass of a polyol 13 having 2 functional groups and a hydroxyl value of 951 was used.
[Example 9]
(A-3) As a low molecular weight polyol component, 3.5 parts by mass of a polyol 14 having 2 functional groups and a hydroxyl value of 1245 was used.
[Example 10]
(A-3) As a low molecular weight polyol component, 3 parts by mass of a polyol 15 having 2 functional groups and a hydroxyl value of 1808 was used.
[Example 11]
(A-3) As a low molecular polyol component, 5 parts by mass of a polyol 15 having 2 functional groups and a hydroxyl value of 1808 was used.

[Comparative Example 8]
(A-3) As a low molecular polyol component, 3.5 parts by mass of a polyol 12 having 2 functional groups and a hydroxyl value of 837 was used.
The polyol 12 was set to 837 which was lower than the lower limit of the hydroxyl value of 900.
[Comparative Example 9]
(A-3) As a low molecular weight polyol component, 2.0 parts by mass of a polyol 15 having 2 functional groups and a hydroxyl value of 1808 was used.
The mixing ratio of the polyol 15 was set to 2 which was lower than the lower limit of the mixing ratios 3 to 5 of the (A-3) low molecular weight polyol component in the (A) polyol component.
[Comparative Example 10]
(A-3) As a low molecular weight polyol component, 6.0 parts by mass of a polyol 15 having 2 functional groups and a hydroxyl value of 1808 was used.
The mixing ratio of the polyol 15 was set to a ratio 6 exceeding the upper limit value among the mixing ratios 3 to 5 of the (A-3) low molecular weight polyol component in the (A) polyol component.
In Examples 8 to 11 and Comparative Examples 8 to 10,
(A-1) The polyol component uses polyol 3,
(A-2) Hyper-branch polymer uses polyol 10,
(B) Isocyanate 2 was used as the polyisocyanate component.

[Example 12]
(B) 58 parts by mass of isocyanate 1 was used as a polyisocyanate component.
Example 13
(B) As a polyisocyanate component,
(B) NCO / OH ratio (INDEX) indicating the reaction ratio of the polyisocyanate component and the polyol component (INDEX) = 1.0 to 1.1, and the lower limit of 1.0 is 86.4 parts by mass of isocyanate 2. used.
[Example 14]
(B) As a polyisocyanate component,
95.1 parts by mass of isocyanate 2 with an upper limit of 1.1 out of NCO / OH ratio (INDEX) = 1.0 to 1.1 indicating a reaction ratio between (B) polyisocyanate component and (A) polyol component. used.

[Example 15]
(B) As a polyisocyanate component, the NCO mass% of isocyanate 3, which is a prepolymer, was 10.0. In the present invention, the remaining amount of the active isocyanate group (NCO group) at the terminal is 10 to 23% by mass, but the lower limit is 10.
[Example 16]
(B) As a polyisocyanate component, the NCO mass% of isocyanate 3 as a prepolymer was set to 23.0. In the present invention, the remaining amount of the active isocyanate group (NCO group) at the terminal is 10 to 23% by mass, but the upper limit is 23.
In addition, when the NCO mass% is out of this range with respect to 10 to 23%, it is omitted because the effect of using the prepolymer is lost or the viscosity is increased to hinder foaming.

[Comparative Example 11]
Among the NCO / OH ratios (INDEX) = 1.0 to 1.1 indicating the reaction ratio between the (B) polyisocyanate component and the (A) polyol component, INDEX = 0.9, which is lower than the lower limit 1.0, was set. .
In addition, those exceeding the INDEX maximum value 1.1 were omitted as comparative examples because of lack of stability over time of the hardness of the urethane foam.
In Examples 12 to 16 and Comparative Example 11,
The polyol component (A-1) uses a polyol 3,
The polyol component (A-2) uses the polyol 10,
Polyol 15 was used as the polyol component (A-3).

<Soft polyurethane foam>
Using the above materials, the reaction was started by mixing with a homogenizer (3000 rpm / min) for 15 seconds in accordance with the prescription shown in Tables 1 to 4, and the mixture was put into a 220 × 220 mm, 10 mm thick mold from 205. After casting 210 g, the flask was covered, the reaction was continued at a temperature of 80 ° C. for 15 minutes, then demolded, and then cured at 100 ° C. for 2 hours. As a result, a sheet-shaped flexible polyurethane foam having a size of 220 × 220 mm, a thickness of 10 mm, and an apparent density of 0.42 to 0.43 g / cm ³ was obtained.

  The following experiments were performed on the obtained sheet-like flexible polyurethane foam, and the results are shown in Tables 5 to 8.

In the table, the hardness is 50 or less.
Compression set is
A: 5% or less B: More than 5 and 10% or less X: More than 10 and 20% or less XX: Vibration isolation of more than 20%
A: 0.3 or more B: 0.2 or more and less than 0.3 x: 0.1 or more and less than 0.2 xx: less than 0.1
Compression creep is
A: Change rate less than 10% B: Change rate 10 or more and less than 20% X: Change rate 20 or more and less than 30% XX: Change rate 30% or more.

  In Tables 1 to 4, the unit of the numerical value in the column of the formulation indicates parts by mass, and INDEX (NCO / OH ratio) is (A) polyol component + (C) the prepolymer to the hydroxyl group (OH) of water. It shows the equivalent ratio of isocyanate groups (NCO groups).

  "Rubber hardness" in Tables 5 to 8 is a numerical value obtained as a result of measurement using a spring-type rubber hardness meter (A type) according to JIS K6301.

The “compression set” as an evaluation is measured according to JIS K6301 (compression rate 50%, 70 ° C., 24 hours), and is expressed as a permanent set amount (%) with respect to the compression deformation length.
Here, the meaning of A, B, xx, and xx shown as the evaluation of “compression set” is A when the permanent set is 5% or less, and B when it is more than 5% and 10% or less. , Those in the range of more than 10% and 20% or less were evaluated as x, and those exceeding 20% were evaluated as xx.
The natural rubber conventionally used as a vibration-proof material had a permanent set of 30 to 50% (evaluation xx).

The “15% compressive strength” as an evaluation was obtained by performing a compression test in accordance with JIS K6911 and expressing the stress (unit: kg / cm ² ) at 15% strain (so-called compression at 15% strain). Strength).

The “vibration resistance” as an evaluation was measured by a dynamic bending test (viscoelasticity analyzer RSA-II, Rheometric, Inc.) using the obtained flexible polyurethane foam as a test piece having a thickness of 50 mm × 50 mm × 10 mm. It is a numerical value (so-called tan δ) of the measurement result at 23 ° C.
The meanings of A, B, X, and XX shown in the evaluation of vibration isolation (tan δ) are as follows: A when the measured value is 0.3 or more; And those having a range of less than 0.2 and 0.1 or more were evaluated as x, and those less than 0.1 were evaluated as xx.
In addition, it was about 0.1 (evaluation x below) about the natural rubber for vibration damping materials.

The “compression creep property” as an evaluation is such that a load is applied to the obtained flexible polyurethane foam member under the conditions of an ambient temperature of 70 ° C. and a compressive stress of 0.8 to 1.2 kg / cm ² , The stress was such that the polyurethane foam member) deformed about 10% in the initial stage of load (instantaneous elastic deformation).
(JIS K6767 expanded plastic-polyethylene-test method, or JIS K6385 anti-vibration rubber-test method)

  The meanings of A, B, XX, and XX shown in the evaluation of compression creep are as follows. A stress equivalent to about 10% deformation is applied at the initial stage of load (instantaneous elastic deformation), and the thickness is reduced to 0 hour (the value before the test). )), Those having a thickness change rate of less than 10% after 1000 hours are designated as A, those having a thickness change rate of 10% or more and less than 20% as B, and those having a thickness change rate of 20% or more and less than 30%. , And those with a thickness change rate of 30% or more were XX.

From the results shown in Tables 5 to 8, the flexible polyurethane foams molded by the formulations of the examples according to the present invention are excellent in hardness, compression set, 15% compressive strength, and also excellent in vibration isolation (tan δ). (2 to 3 times of rubber for vibration isolation).
On the other hand, it can be seen that the flexible polyurethane foams molded by the formulations of Comparative Examples 1 to 11 are inferior in compression set and compression creep.

The flexible polyurethane foam of the present invention has excellent vibration damping properties, compression set and compression creep properties, and can be used as a vibration damping member, a vibration damping member, a shock absorbing member, and the like. For example, it can be suitably used as an anti-vibration member or the like, which does not like to increase the deformation amount with the passage of time under load.
Furthermore, the flexible polyurethane foam of the present invention has excellent compression set and compression creep even under a load over a long period of time, and thus can be suitably used as a cushioning member.
Further, as another application, for example, in a two-story house or more, if the flexible polyurethane foam of the present invention is placed as a cushioning material between above the beam supporting the floor and below the floor, floor vibration and impact on the floor can be suppressed. Therefore, it can be suitably used as a noise suppression member, and has extremely high industrial applicability.

Claims (4)

A compression set of 10% or less and a vibration damping property (tan δ measured by a dynamic bending test) produced from a composition obtained by reacting the following (A) polyol component, (B) polyisocyanate component, and (C) water. ) Is 0.2 or more, and the compression creep property is less than 20%.
(A) a polyol component,
(A-1) a polyol having a functional hydroxyl number of 2.0 to 3.0 and a hydroxyl value of 20 to 170 and having an active hydroxyl group at a terminal,
(A-2) 4 to 8 parts by mass of a hyperbranched polymer having 4 or more functional groups and a hydroxyl value of 380 or more and having an active hydroxyl group at a terminal;
(A-3) a mixture of 3 to 5 parts by mass of a low molecular polyol having a functional group number of 2.0 to 3.0 and a hydroxyl value of 900 to 2000,
(B) the polyisocyanate component is diphenyl-methane-diisocyanate (MDI) or a derivative thereof,
(C) water,
The equivalent ratio (NCO / OH ratio) of the isocyanate group (NCO group) of the prepolymer to the (A) polyol component + (C) water hydroxyl group (OH) is 1.00 to 1.10.
(A-2) The hyperbranched polymer having an active hydroxyl group at a terminal,
The flexible polyurethane foam according to claim 1, which is a compound obtained by self-condensation of dimethylol fatty acid .
(A-2) The hyperbranched polymer having an active hydroxyl group at a terminal,
The flexible polyurethane foam according to claim 1 or 2, wherein the compound is a compound obtained by reacting 1 mol of diisocyanate with 2 mol of triol .
The derivative (B) of diphenyl-methane-diisocyanate (MDI) as the polyisocyanate component is a prepolymer having an active isocyanate group at a terminal obtained from a reaction between polytetramethylene ether glycol and a polyisocyanate compound. The flexible polyurethane foam according to any one of claims 1 to 3.