CN120303317A

CN120303317A - Polyurethane foam

Info

Publication number: CN120303317A
Application number: CN202380083088.5A
Authority: CN
Inventors: 小岛贯也
Original assignee: Inoac Corp
Current assignee: Inoac Corp
Priority date: 2022-12-05
Filing date: 2023-12-01
Publication date: 2025-07-11
Also published as: WO2024122477A1; JPWO2024122477A1

Abstract

Polyurethane foam is obtained by foaming and reacting a raw material mixture containing a compound having an active hydrogen atom and a polyisocyanate. The compound having an active hydrogen atom includes more than 40.0 mass% of polyol A, more than 0 mass% of polyol B, and more than 0 mass% and less than 15.0 mass% of monol C. Here, "polyol a" means a polyether polyol having a weight average molecular weight of 3000 or more and an EO content of less than 50.0 mass%, "polyol B" means a polyether polyol having an EO content of 50.0 mass% or more, and "monol C" means a monol having a weight average molecular weight of 2000 or more.

Description

Polyurethane foam

Technical Field

The present invention relates to a polyurethane foam, and in particular, to a polyurethane foam having a combination of low hardness, high resilience, and low compression set.

Background

Polyurethane refers to a high molecular compound having a urethane bond (-NH-C (O) O-). Polyurethanes are generally obtained by reacting hydroxyl groups (-OH) of a polyol with isocyanate groups (-NCO) of a polyisocyanate. By optimizing the type of polyol and/or polyisocyanate, it is known that polyurethanes exhibit a variety of properties. Therefore, polyurethane is applied to various automobile parts, synthetic leather, paint, adhesives, and the like. Further, polyurethane foam obtained by foaming polyurethane is used for heat insulating materials, cushioning materials, and the like.

Polyurethane foams with increased resilience are also referred to in particular as "high resilience polyurethane foams". The high resilience polyurethane foam is used for clothing, sports goods, toys, bedding, interior trim and the like because of its strong resilience and being not easy to collapse and deform.

Various proposals have been made in the past for such high resilience polyurethane foams.

For example, patent document 1 discloses a flexible polyurethane foam obtained by reacting a raw material mixture comprising:

(a) 70 parts by mass of Propylene Oxide (PO) -Ethylene Oxide (EO) adduct of glycerin (molecular weight: 3000);

(b) 25 parts by mass of a PO adduct of pentaerythritol (molecular weight 2000);

(c) PO-EO adduct of n-butanol (molecular weight: 600) 5 parts by mass, and

(D) Prescribed amounts of water, triethylenediamine 33% dipropylene glycol solution, dimethylsiloxane-based foam stabilizer, stannous octoate, and T-80 (80/20 mixture of 2,4-TDI and 2, 6-TDI).

This document describes that the following flexible polyurethane foams are obtained by this method:

(A) The 25% ILD was 11.4kg/314cm ²,

(B) The compression set was 7.3%,

(C) The modulus of elasticity in rebound was 42%.

Patent document 2 discloses a flexible polyurethane foam, the flexible polyurethane foam is obtained by reacting a raw material mixture comprising the following components:

(a) 100 parts of polyether polyol (hydroxyl number 56);

(b) 3 parts of a polyether monol obtained by adding 7mol of PO to 1mol of n-butanol, and

(C) Prescribed amounts of water, silicone foam stabilizer, stannous octoate, triethylenediamine, and T-80.

(A) The hardness is 9.7kg/314cm ²,

(B) The permanent set is 10.6%,

(C) The modulus of elasticity in rebound was 41%.

Patent document 3 discloses a low resilience flexible polyurethane foam, which is not a high resilience polyurethane foam, but is obtained by reacting a raw material mixture comprising:

(a) 21.6 parts by mass of a polyoxypropylene polyol (polyol A2) having an average hydroxyl number of 2 and a hydroxyl number of 14mgKOH/g and an EO content of 0%;

(b) 30.2 parts by mass of a polyoxypropylene polyol (polyol B1) having an average hydroxyl number of 2 and a hydroxyl number of 160mgKOH/g and an EO content of 0%;

(c) 31.5 parts by mass of a polyoxypropylene polyol (polyol B2) having an average hydroxyl number of 3 and a hydroxyl number of 168mgKOH/g and an EO content of 0%;

(d) 2.8 parts by mass of a polyoxypropylene oxyethylene polyol (polyol B3) having an average hydroxyl number of 3 and a hydroxyl number of 48mgKOH/g and an EO content of 80%;

(e) 13.9 parts by mass of a polyoxypropylene monol (monol D1) having an average hydroxyl number of 1 and a hydroxyl number of 16.7mgKOH/g, and

(F) The specified amounts of blowing agent, foam stabilizer, catalyst and polyisocyanate compound.

This document describes that the following low resilience flexible polyurethane foam is obtained by this method:

(A) The 25% ILD was 73N/314cm ²,

(B) The dry heat compression set was 2.3%,

(C) The core (core) modulus of elasticity was 13%.

Patent document 4 discloses a low resilience flexible polyurethane foam, which is not a high resilience polyurethane foam, but is obtained by reacting a raw material mixture comprising:

(a) 26.3 parts by mass of a polyoxypropylene polyol (polyol A1) having an average hydroxyl number of 2 and a hydroxyl number of 18mgKOH/g and an EO content of 0%;

(b) 36.8 parts by mass of a polyoxypropylene polyol (polyol B1) having an average hydroxyl number of 2 and a hydroxyl number of 160mgKOH/g and an EO content of 0%;

(c) 27.0 parts by mass of a polyoxypropylene polyol (polyol B2) having an average hydroxyl number of 3 and a hydroxyl number of 168mgKOH/g and an EO content of 0%;

(d) 5.4 parts by mass of a polyoxypropylene oxyethylene polyol (polyol C1) having an average hydroxyl group of 3 and a hydroxyl group of 48mgKOH/g and an EO content of 80%;

(e) 4.5 parts by mass of a polyoxypropylene monol (monol D1) having an average hydroxyl number of 1 and a hydroxyl number of 16.7mgKOH/g, and

(F) The specified amounts of blowing agent, catalyst, foam stabilizer and polyisocyanate compound.

(A) The 25% ILD was 48N/314cm ²,

(B) The dry heat compression set was 3.2%,

(C) The core rebound elastic modulus was 11%.

Patent document 5 discloses a low resilience flexible polyurethane foam, which is not a high resilience polyurethane foam, but is obtained by reacting a raw material composition comprising:

(a) 27.7 parts by mass of a polyoxypropylene polyol (polyol A1) having an average hydroxyl number of 2 and a hydroxyl number of 14mgKOH/g and an EO content of 0%;

(b) 38.8 parts by mass of a polyoxypropylene polyol (polyol B1) having an average hydroxyl number of 2 and a hydroxyl number of 160mgKOH/g and an EO content of 0%;

(c) 31 parts by mass of a polyoxypropylene polyol (polyol B2) having an average hydroxyl number of 3 and a hydroxyl number of 168mgKOH/g and an EO content of 0%;

(d) 6 parts by mass of a polyoxypropylene oxyethylene polyol (polyol C) having an average hydroxyl number of 3 and a hydroxyl number of 48mgKOH/g and an EO content of 80%;

(e) 7.5 parts by mass of a polyoxypropylene monol (monol D) having an average hydroxyl number of 1 and a hydroxyl number of 17mgKOH/g, and

(F) The prescribed amounts of catalyst, blowing agent, foam stabilizer, and polyisocyanate compound.

(A) The 25% ILD was 13N/314cm ²,

(B) The dry heat compression set was 42.1%,

(C) The modulus of elasticity in rebound was 1%.

Patent document 6 discloses a low resilience flexible polyurethane foam, which is not a high resilience polyurethane foam, but is obtained by reacting a raw material composition comprising:

(a) 21.2 parts by mass of a polyoxypropylene polyol (polyol A1) having an average hydroxyl number of 2 and a hydroxyl number of 11mgKOH/g and an EO content of 0%;

(b) 29.7 parts by mass of a polyoxypropylene polyol (polyol B1) having an average hydroxyl number of 2 and a hydroxyl number of 160mgKOH/g and an EO content of 0%;

(c) 36.9 parts by mass of a polyoxypropylene polyol (polyol B2) having an average hydroxyl number of 3 and a hydroxyl number of 168mgKOH/g and an EO content of 0%;

(d) 5.4 parts by mass of a polyoxypropylene oxyethylene polyol (polyol C1) having an average hydroxyl number of 3 and a hydroxyl number of 48mgKOH/g and an EO content of 80%;

(e) 6.8 parts by mass of a polyoxypropylene monol (monol D1) having an average hydroxyl number of 1 and a hydroxyl number of 16.7mgKOH/g, and

(F) The specified amounts of blowing agent, foam stabilizer, catalyst, and polyisocyanate compound.

(A) The 25% ILD was 53N/314cm ²,

(B) The 50% compressive residual strain was 20.7%,

(C) The core rebound elastic modulus was 11%.

Polyurethane foams for certain applications (e.g., apparel applications) are not only required to have high resilience, but also to be soft to the touch. As a method for softening a polyurethane foam, for example,

(A) A process using a high molecular weight polyol,

(B) A method of using a polyol having a high EO content,

(C) A method using a low molecular weight monoalcohol, and the like.

However, with the method of softening using only a high molecular weight polyol, since cells are easily formed into an independent bubble structure, the following problems may occur:

(a) The polyurethane foam itself, although having a reduced hardness, gives a "taut feel" leaving a hardness to the touch,

(B) The compression set of the polyurethane foam increases,

(C) The air permeability of the polyurethane foam decreases, etc.

In addition, in the method of softening using a large amount of polyol having a high EO content, there is a possibility that (a) the water resistance is lowered due to the increase of the hydrophilicity of the polyurethane foam,

(B) Polyurethane foams absorb moisture, cause adhesion (tackiness) between cell walls, decrease resilience,

(C) Bubble communication proceeds excessively, producing cell roughness, and the like.

In addition, in the method of softening using only a low molecular weight monoalcohol, since the monoalcohol moiety stops polymerization, the crosslinking density of the polymer decreases, and the strength of the resin decreases, the following problems may occur:

(a) The resilience of the polyurethane foam is reduced and,

(B) Compression set of polyurethane foam increases, etc.

Prior art literature

Patent literature

Japanese patent application laid-open No. 04-146916

Japanese patent application laid-open No. 05-287047

Patent document 3 International publication No. 2006/115169

Patent document 4 International publication No. 2008/050841

Patent document 5 International publication No. 2009/04535

Patent document 6 Japanese patent application laid-open No. 2013-127011

Disclosure of Invention

Problems to be solved by the invention

The present invention aims to provide a novel polyurethane foam having low hardness, high rebound resilience and low compression set.

Means for solving the problems

In order to solve the above problems, a polyurethane foam according to a first embodiment of the present invention is obtained by foaming and reacting a raw material mixture comprising:

A compound having an active hydrogen atom, and

The presence of a polyisocyanate(s) is known,

The above-mentioned compound having an active hydrogen atom includes:

More than 40.0 mass% of polyol a;

More than 0 mass% of polyol B, and

More than 0 mass% and less than 15.0 mass% of monoalcohol C.

Wherein, the

The term "polyol A" means one or two or more polyether polyols having a weight average molecular weight of 3000 or more and an EO content of less than 50.0 mass%,

The term "polyol B" means one or two or more polyether polyols having an EO content of 50.0 mass% or more,

The term "monoalcohol C" as used herein means one or two or more monoalcohols having a weight average molecular weight of 2000 or more,

"Mass%" indicating the content of the polyol a, the polyol B, or the monol C means a ratio of the mass of the polyol a, the polyol B, or the monol C to the total mass of the compound having an active hydrogen atom, respectively.

Polyurethane foam according to the second embodiment of the present invention

Using a monoalcohol C having a weight average molecular weight of 2000 or more as a raw material,

The rebound elastic modulus is more than 35 percent,

Asker F hardness was 35 or less.

The "modulus of elasticity" refers to a value measured in accordance with JIS K6255.

Effects of the invention

In the production of polyurethane foam, a polyurethane foam having low hardness, high rebound resilience and low compression set can be obtained by adding a monoalcohol C (ether-based high molecular weight monoalcohol) as a raw material. The reason for this is considered to be that the use of the monoalcohol C causes a decrease in the crosslinking density and an increase in the intermolecular repulsion.

Detailed Description

An embodiment of the present invention will be described in detail below.

[ 1] Polyurethane foam (1)

The polyurethane foam according to the first embodiment of the present invention is obtained by foaming and reacting a raw material mixture comprising:

Compounds having active hydrogen atoms, and

And (3) a polyisocyanate.

[1.1. Ingredients ]

The raw material mixture contains at least a compound having an active hydrogen atom and a polyisocyanate. The raw material mixture generally contains a foaming agent, a catalyst, a foam stabilizer, and the like in addition to the above.

[1.1.1. Compounds having active Hydrogen atoms ]

"A compound having an active hydrogen atom (hereinafter also referred to as" active hydrogen compound ")" refers to a compound having one or more "functional groups having an active hydrogen atom" in a molecule. Examples of the functional group having an active hydrogen atom include a hydroxyl group, an amino group, an imino group, a carboxyl group, a urethane group and a urea group.

In the present invention, the active hydrogen compound contains at least polyol a, polyol B, and monol C described later. The active hydrogen compound may further comprise a polyhydric alcohol and/or a monohydric alcohol other than the above.

[ Polyol A ]

[ A.1. Definition ]

In the present invention, the term "polyol a" means a polyether polyol (ether-based high-molecular-weight polyol) having a weight average molecular weight of 3000 or more and an EO content of less than 50.0 mass%.

Polyol a is one of the main raw materials for manufacturing polyurethane foam. Polyol a may be composed of any one polyether polyol satisfying the above conditions, or may be a mixture of two or more polyether polyols.

[ A.2. weight average molecular weight ]

In the present invention, the "weight average molecular weight" refers to a value calculated based on the molecular weight of the standard polyethylene based on a chromatogram obtained by measurement by gel permeation chromatography (Gel Permeation Chromatography, GPC).

If the weight average molecular weight of the polyol a is too small, the proportion of soft segments present may decrease, and the hardness of the polyurethane foam may become too high. Therefore, the weight average molecular weight of polyol a needs to be 3000 or more. The weight average molecular weight is preferably 4500 or more, or 6000 or more.

On the other hand, if the weight average molecular weight of the polyol a is too large, the ratio of urethane bonds (the ratio of hard segments) may be too low to obtain a desired hardness. In addition, even if foaming is temporarily performed when the raw material mixture is reacted, bubbles may escape from the raw material mixture during curing, so that it is difficult to maintain the foam (not to form foam). In addition, since the viscosity of the raw material mixture becomes too high, there is a possibility that stirring failure of the raw material mixture occurs and unevenness is easily caused. Therefore, the weight average molecular weight of polyol a is preferably 12000 or less. The weight average molecular weight is preferably 11000 or less, 10000 or less, or 9000 or less.

[ A.3.EO content ]

"EO content (mass%) of the polyol A means a ratio of the mass of Ethylene Oxide (EO) units to the total mass of the alkylene oxide (alkylene oxide) units contained in the polyol A.

Polyol a contains alkylene oxide units other than EO units. In this case, the kind of alkylene oxide unit other than the EO unit is not particularly limited, but Propylene Oxide (PO) unit is preferable.

If the EO content of polyol A becomes too large, so-called "cell coarsening" may occur. That is, a part of cells may be combined with each other and form large cells, so that the cell size becomes uneven in size. In addition, a part of cells may become a state where the entire cell membrane is lost and only the cell skeleton remains. Therefore, the EO content of polyol A needs to be less than 50.0 mass%. The Eo content is preferably 25.0 mass% or less, 20.0 mass% or less, or 16.0 mass% or less.

On the other hand, if the EO content of the polyol a becomes too small, the bubbles are liable to become independent bubbles. As a result, the degassing effect may be insufficient, and the feel may become hard. In addition, during cooling after the reaction, the foam may neck (i.e., shrink). Therefore, the EO content of the polyol A is preferably 5.0% by mass or more. The EO content is more preferably 8.0 mass% or more, 10.0 mass% or more, or 12.0 mass% or more.

[ Number of functional groups A.4 ]

The number of functional groups of the polyol A is not particularly limited, and an optimum value may be selected according to the purpose. In general, if the number of functional groups of the polyol a is too small, formation of a steric network may be insufficient, and thus heat curing may be difficult. Therefore, the number of functional groups of the polyol A is preferably 2.5 or more. The number of functional groups is more preferably 2.6 or more, or 2.7 or more.

On the other hand, if the number of functional groups of the polyol a is too large, the hardness of the polyurethane foam may become too high. Therefore, the number of functional groups of the polyol A is preferably 4.0 or less. The number of functional groups is more preferably 3.5 or less, or 3.3 or less.

[ Polyol B ]

[ B.1. Definition ]

In the present invention, "polyol B" means a polyether polyol (ether-based high EO polyol) having an EO content of 50.0 mass% or more.

Polyol B is an auxiliary raw material for controlling the hardness and air permeability of the polyurethane foam. Polyol B may be composed of any one polyether polyol satisfying the above conditions, or may be a mixture of two or more polyether polyols.

[ B.2.EO content ]

The "EO content (mass%) of the polyol B means a ratio of the mass of Ethylene Oxide (EO) units contained in the polyol B to the total mass of the alkylene oxide units.

Polyol B may contain alkylene oxide units other than EO units. In this case, the kind of alkylene oxide unit other than the EO unit is not particularly limited, but Propylene Oxide (PO) unit is preferable.

If the EO content of the polyol B is too small, the function as an exhaust agent (function of communicating bubbles) may be impaired. Therefore, the EO content of the polyol B is required to be 50.0 mass% or more. The EO content is preferably 60.0% by mass or more, or 70.0% by mass or more. The EO content of the polyol B may be 100.0% by mass.

[ B.3. weight average molecular weight ]

The weight average molecular weight of the polyol B is not particularly limited, and an optimum value may be selected according to purposes. In general, if the weight average molecular weight of the polyol B is too small, the hardness of the polyurethane foam may become too high. Therefore, the weight average molecular weight of the polyol B is preferably 2500 or more. The weight average molecular weight is more preferably 2700 or more, or 3000 or more.

On the other hand, if the weight average molecular weight of the polyol B is too large, the ratio of urethane bonds (the ratio of hard segments) may be too low to obtain a desired hardness. In addition, even if foaming is temporarily performed when the raw material mixture is reacted, bubbles may escape from the raw material mixture during curing, so that it is difficult to maintain the foam (not to form foam). In addition, since the viscosity of the raw material mixture becomes too high, there is a possibility that stirring failure of the raw material mixture occurs and unevenness is easily caused. Therefore, the weight average molecular weight of the polyol B is preferably 12000 or less. The weight average molecular weight is more preferably 10000 or less, 8000 or less, 6000 or less, or 4000 or less.

[ Number of functional groups B.4 ]

The number of functional groups of the polyol B is not particularly limited, and an optimum value may be selected according to the purpose. In general, if the number of functional groups of the polyol B is too small, formation of a steric network may be insufficient, and thus heat curing may be difficult. Therefore, the number of functional groups of the polyol B is preferably 2.5 or more. The number of functional groups is more preferably 2.6 or more, or 2.7 or more.

On the other hand, if the number of functional groups of the polyol B is too large, the hardness of the polyurethane foam may become too high. Therefore, the number of functional groups of the polyol B is preferably 3.5 or less. The number of functional groups is more preferably 3.4 or less, or 3.3 or less.

[ C. MonoC ]

[ C.1. Definition ]

In the present invention, "monoalcohol C" means a monoalcohol (ether-based high molecular weight monoalcohol) having a weight average molecular weight of 2000 or more.

Monol C is an auxiliary material for controlling the hardness, resilience and compression set of polyurethane foam. The monoalcohol C may be composed of any one monoalcohol satisfying the above conditions, or may be a mixture of two or more monoalcohols.

[ C.2. weight average molecular weight ]

If the weight average molecular weight of the monool C is too small, compression set of the polyurethane foam may be increased. Therefore, the weight average molecular weight of the monol C needs to be 2000 or more. The weight average molecular weight is preferably 2300 or more, 2600 or more, 2900 or more, or 3000 or more.

On the other hand, if the weight average molecular weight of the monool C is too large, there is a possibility that the cells become independent cells, and the polyurethane foam shrinks during cooling after the reaction. Therefore, the weight average molecular weight of the monoalcohol C is preferably 12000 or less. The weight average molecular weight is preferably 10000 or less, 8000 or less, or 6000 or less.

[ C.3.EO content ]

The "EO content" of the monol C means a ratio of the mass of Ethylene Oxide (EO) units contained in the monol C to the total mass of the alkylene oxide units.

In the present invention, the EO content of the monol C is not particularly limited, and an optimum value may be selected according to the purpose. The EO content of the monol C is usually 0% by mass, but may be any value between 0 and 100% by mass.

In the case where the monol C contains an alkylene oxide unit other than an EO unit, the kind of the alkylene oxide unit other than an EO unit is not particularly limited, but a Propylene Oxide (PO) unit is preferable.

[ Number of functional groups of C.4 ]

Theoretically, the number of functional groups of the monoalcohol C is 1. However, the impurity (polyol) is inevitably mixed into the monool C, and the apparent functional group number of the monool C may sometimes exceed 1. In the present invention, the number of functional groups of the monoalcohol C may also exceed 1.

However, if the number of functional groups of the monool C is too large, the hardness of the polyurethane foam may become too high. Therefore, the number of functional groups of the monoalcohol C is preferably 1.1 or less. The number of functional groups is more preferably 1.05 or less, 1.03 or less, or 1.01 or less.

[ D. other polyols and monoalcohols ]

The active hydrogen compound may contain only polyol a, polyol B and monol C, or may also contain other polyols and/or monols.

Examples of the other polyols and monoalcohols include:

(a) Polyether polyols other than polyol a and polyol B;

(b) A monoalcohol other than monoalcohol C;

(c) A polyester polyol;

(d) A polymer polyol;

(e) A polycarbonate diol;

(f) A polyolefin-based polyol;

(g) A plant-derived polyol.

[1.1.2. Polyisocyanates ]

"Polyisocyanate" is another main raw material for producing polyurethane foam, and refers to a compound having two or more isocyanate groups in one molecule.

In the present invention, the kind of polyisocyanate is not particularly limited. In addition, one kind of polyisocyanate may be contained in the raw material mixture, or two or more kinds may be contained.

As the polyisocyanate, there are:

(a) An aromatic isocyanate compound, an aliphatic isocyanate compound or a cycloaliphatic isocyanate compound, and

(B) Modifications of the above compounds, and the like.

Examples of the aromatic isocyanate compound include,

Diphenylmethane diisocyanate (MDI),

Crude diphenylmethane diisocyanate, toluene Diisocyanate (TDI),

Naphthalene Diisocyanate (NDI),

Para-phenylene diisocyanate (PPDI), meta-xylylene isocyanate (XDI),

Tetramethyl m-xylylene diisocyanate (TMXDI),

Dimethylbiphenyl diisocyanate (TODI), and the like.

Among them, MDI is suitable as a polyisocyanate for manufacturing polyurethane foam. MDI has three isomers, namely, 2 '-diphenylmethane diisocyanate (2, 2' -MDI),

2,4 '-Diphenylmethane diisocyanate (2, 4' -MDI), and

4,4 '-Diphenylmethane diisocyanate (4, 4' -MDI).

The polyisocyanate may contain an isomer of any of these, or may contain two or more kinds.

Examples of the aliphatic isocyanate compound include,

Hexamethylene Diisocyanate (HDI), lysine Diisocyanate (LDI),

Lysine Triisocyanate (LTI), and the like.

Examples of the alicyclic isocyanate compound include,

Isophorone diisocyanate (IPDI),

Cyclohexane diisocyanate (CHDI), hydrogenated XDI (H ₆ XDI),

Hydrogenated MDI (H ₁₂ MDI), and the like.

Examples of the modified isocyanate compound include urethane (urethane) modified products, dimers, trimers, carbodiimide modified products, allophanate modified products, biuret modified products, urea modified products, isocyanurate modified products, oxazolidone modified products, and isocyanate group-terminated prepolymers of isocyanate compounds.

[1.1.3. Foaming agent ]

"Blowing agent" refers to an additive that is used to create bubbles in a raw material mixture during the resinification of the liquid raw material mixture.

In the present invention, the foaming agent may be any of the following:

(a) Physical blowing agents, or by gas generation by pressure drop or heating

(B) Chemical blowing agents that produce gases by thermal decomposition or chemical reactions.

Examples of the physical foaming agent include:

(a-1) hydrocarbons such as cyclopentane, isopentane, n-pentane, etc., and

And (a-2) halogen compounds such as methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, pentafluoroethyl methyl ether and heptafluoroisopropyl methyl ether (Perfluoroisopropyl METHYL ETHER).

Examples of the chemical foaming agent include:

(b-1) water which reacts with isocyanate groups to form CO ₂, and

(B-2) azodicarbonamide producing nitrogen, carbon monoxide, carbon dioxide or ammonia by thermal decomposition, and the like.

Any one of these blowing agents may be contained in the raw material mixture, or two or more kinds may be contained.

Among them, the foaming agent is preferably water. When water is used as the blowing agent, the CO ₂ gas generated by the reaction of water with isocyanate groups promotes the foaming. In addition, the heat of reaction between water and isocyanate groups promotes curing of the resin.

[1.1.4. Catalyst ]

The "catalyst" refers to a catalyst that promotes a resinification reaction, a catalyst that promotes a foaming reaction, or a catalyst that promotes both a resinification reaction and a foaming reaction.

Examples of the catalyst include amine-based catalysts and metal catalysts. The amine-based catalyst is a catalyst that promotes both the resinification reaction and the foaming reaction. The metal catalyst is a catalyst that promotes the resinification reaction. The raw material mixture may contain any one of these catalysts, or may contain two or more kinds thereof.

Examples of the amine-based catalyst include,

N, N-dimethylcyclohexylamine, N-dimethylbenzylamine,

N, N-dimethylaminoethanol,

N, N' -trimethylaminoethylpiperazine, triethylenediamine, and the like.

Examples of the metal catalyst include:

(a) Tin catalysts such as stannous octoate (Stannous Octoate) and dibutyltin dilaurate;

(b) Mercury catalyst such as phenylmercuric propionate (phenylmercuric propionate), and

(C) Lead catalysts such as lead octoate.

[1.1.5. Foam stabilizer ]

"Foam stabilizer" refers to an additive that has the effect of homogenizing the size and distribution of bubbles.

If a foam stabilizer is added to the raw material mixture, a polyurethane foam having a uniform cell size and distribution can be obtained. Examples of the foam stabilizer include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, and known surfactants.

[1.2. Content ]

[1.2.1. Polyol A content ]

"Content of polyol A (mass%)" refers to the ratio of the mass of polyol A to the total mass of active hydrogen compounds.

If the content of polyol A is too low, the hardness may be increased, the rebound resilience may be decreased, or the compression set may be increased. Therefore, the content of polyol A needs to exceed 40 mass%. The content is preferably 50.0 mass% or more, 60.0 mass% or more, 70.0 mass% or more, or 80.0 mass% or more.

On the other hand, if the content of polyol a is excessive, compression set may increase instead. If the content of polyol a is excessive, independent bubbles are easily formed. Therefore, the polyurethane foam may shrink and the rebound resilience may be lowered during cooling after the reaction. Therefore, the content of polyol A needs to be less than 100.0 mass%. The content is preferably 95.0 mass% or less, or 90.0 mass% or less.

[1.2.2. Polyol B content ]

"Content of polyol B (mass%)" refers to the ratio of the mass of polyol B to the total mass of active hydrogen compounds.

If the content of polyol B is too low, the degassing effect may be insufficient and the polyurethane foam may become hard. In addition, the polyurethane foam may shrink during cooling after the reaction. Therefore, the content of polyol B needs to exceed 0.0 mass%. The content is preferably 0.5 mass% or more, 1.0 mass% or more, or 2.0 mass% or more.

On the other hand, if the content of polyol B is excessive, cell coarsening may occur. In addition, a part of cells may become a state where the entire cell membrane is lost and only the cell skeleton remains. Therefore, the content of polyol B is preferably 25.0 mass% or less. The content is preferably 20.0 mass% or less, 15.0 mass% or less, 12.0 mass% or less, or 10.0 mass% or less.

[1.2.3. Content of monoalcohol C ]

"Content of the monoalcohol C (mass%)" means a ratio of the mass of the monoalcohol C to the total mass of the active hydrogen compound.

If the content of the monoalcohol C is too low, the hardness may be increased, the rebound resilience may be decreased, or the compression set may be increased. Therefore, the content of the monoalcohol C needs to exceed 0.0 mass%. The content is preferably 1.0 mass% or more, 2.0 mass% or more, 3.0 mass% or more, or 4.0 mass% or more.

On the other hand, if the content of the monoalcohol C is excessive, the ratio of urethane bonds (the ratio of hard segments) may be too low to obtain the desired hardness. In addition, even if foaming is temporarily performed when the raw material mixture is reacted, bubbles may escape from the raw material mixture during curing, so that it is difficult to maintain the foam (not to form foam). Therefore, the content of the monoalcohol C needs to be less than 15.0 mass%. The content is preferably 14.0 mass% or less, or 13.0 mass% or less.

[1.2.4. Content of other polyol and monoalcohol ]

"Content of other polyol and mono-alcohol (mass%)" refers to the ratio of the total mass of other polyol and mono-alcohol to the total mass of active hydrogen compound.

The active hydrogen compound may also contain polyols and/or monoalcohols other than the above-described polyol a, polyol B, and monoalcohol C. However, if the content of the other polyol and the monoalcohol is excessive, there is a possibility that the hardness increases, the rebound resilience decreases, or the compression set increases. Therefore, the content of the other polyol and the monoalcohol is preferably 50.0 mass% or less. The content is more preferably 25.0 mass% or less, 10.0 mass% or less, or 5.0 mass% or less.

[1.2.5. Isocyanate index ]

"Isocyanate index" refers to the value obtained by multiplying the ratio of the equivalents of isocyanate groups of the polyisocyanate in the raw material mixture to the equivalents of active hydrogen groups in the raw material mixture by 100.

In the present invention, the isocyanate index is not particularly limited, and an optimum value may be selected according to purposes. In general, the greater the isocyanate index, the greater the number of crosslinking points and therefore the better the strength and toughness of the polyurethane foam. Therefore, the isocyanate index is preferably 80 or more. The isocyanate index is more preferably 85 or more, or 90 or more.

On the other hand, if the isocyanate index is too large, the hardness of the polyurethane foam may become too high. Therefore, the isocyanate index is preferably 110 or less. The isocyanate index is more preferably 105 or less, or 100 or less.

[1.2.6. Content of blowing agent ]

"Content of the foaming agent" means the mass of the foaming agent based on 100 total mass of the active hydrogen compound.

The content of the foaming agent is preferably selected to be optimal according to the kind of the foaming agent.

For example, when the foaming agent is water, generally, the more the water content, the lower the hardness of the polyurethane foam. In order to obtain such an effect, the water content is preferably 1.0 part by mass or more. The content is more preferably 1.5 parts by mass or more, or 2.0 parts by mass or more.

On the other hand, if the water content is excessive, the polyurethane foam may suffer from coarse cells or poor touch. Therefore, the water content is preferably 8.0 parts by mass or less. The content is more preferably 5.0 parts by mass or less, or 3.0 parts by mass or less.

[1.2.7. Catalyst content ]

"Catalyst content" means the mass of the catalyst based on 100 total mass of active hydrogen compounds.

In general, the higher the catalyst content, the shorter the reaction time. In order to obtain such an effect, the content of the catalyst is preferably 0.5 parts by mass or more. The content is more preferably 0.6 parts by mass or more, or 0.7 parts by mass or more.

On the other hand, if the catalyst content is excessive, the polyurethane foam may become excessively hard. Therefore, the content of the catalyst is preferably 1.5 parts by mass or less. The content is more preferably 1.4 parts by mass or less, or 1.3 parts by mass or less.

[1.2.8 Content of foam stabilizer ]

"Content of foam stabilizer" means the mass of the foam stabilizer based on 100 total mass of active hydrogen compounds.

If the foam stabilizer content is too low, it may be difficult to form foam. Therefore, the content of the foam stabilizer is preferably 0.5 parts by mass or more. The content is more preferably 0.6 parts by mass or more, or 0.7 parts by mass or more.

On the other hand, if the content of the foam stabilizer is excessive, there is a possibility that the foam stabilizer becomes independent bubbles, the air permeability is impaired, or the foam stabilizer contracts after foaming, and the touch feeling becomes hard. Therefore, the content of the foam stabilizer is preferably 1.5 parts by mass or less. The content is more preferably 0.9 parts by mass or less, or 0.8 parts by mass or less.

[1.3. Reaction ]

Polyisocyanate (liquid B) is added to and mixed with a raw material mixture (liquid a) containing an active hydrogen compound and other additives, and the mixture is maintained at a predetermined temperature. Thus, a foaming reaction and a resinification reaction occur, thereby obtaining the polyurethane foam according to the present invention.

[1.4. Characteristics ]

[1.4.1. Elastic modulus of rebound ]

The "rebound elastic modulus" means a value measured in accordance with JIS K6255.

The polyurethane foam of the present invention exhibits high resilience because of using a monoalcohol C satisfying predetermined conditions as a raw material. When the production conditions are optimized, the rebound elastic modulus is 35% or more. When the production conditions are further optimized, the rebound elastic modulus is 40% or more, or 45% or more.

[1.4.2.Asker F hardness ]

"Asker F hardness" refers to a value determined using an Asker rubber durometer type F.

The polyurethane foam of the present invention has low hardness because of using the monoalcohol C satisfying the predetermined conditions as the raw material. When the production conditions are optimized, the Asker F hardness is 35 or less. When the production conditions are further optimized, the Asker F hardness is 33 or less, or 30 or less.

[1.4.3 Compression set ]

"Compression set" means a value measured in accordance with JIS K6400-3 (50% compression).

The polyurethane foam of the present invention exhibits low compression set because of using a monoalcohol C satisfying predetermined conditions as a raw material. When the production conditions are optimized, the compression set is 20% or less. When the production conditions are further optimized, the compression set is 17% or less, or 16% or less.

[2 ] Polyurethane foam (2) ]

Polyurethane foam according to the second embodiment of the present invention

The rebound elastic modulus is more than 35 percent,

Asker F hardness was 35 or less.

[2.1. Monoalcohol C ]

The term "monoalcohol C" refers to a monoalcohol (ether-based high molecular weight monoalcohol) having a weight average molecular weight of 2000 or more. The details of the monoalcohol C are as described above, and therefore, the description thereof is omitted.

[2.2. Modulus of elasticity in rebound ]

The polyurethane foam according to the present embodiment has a rebound elastic modulus of 35% or more. Other aspects regarding the rebound elastic modulus are the same as those of the first embodiment, and therefore, the description thereof is omitted.

[2.3.Asker F hardness ]

The polyurethane foam according to the present embodiment has an Asker F hardness of 35 or less. Other aspects regarding Asker F hardness are the same as the first embodiment, and therefore a description thereof is omitted.

[3 ] Process for producing polyurethane foam ]

The polyurethane foam according to the present invention can be produced by mixing the above-described components as a raw material mixture, and subjecting the mixture to a resinification reaction and a foaming reaction. The method of the resinification reaction and the foaming reaction may be freely combined with a general method as long as the object and effect of the present invention are not impaired.

The foaming in the method for producing a polyurethane foam according to the present invention may be either plate-type (sleb) foaming or die (mould) foaming. Plate foaming is a method of mixing and discharging raw materials for producing polyurethane foam onto a belt conveyor and foaming the mixture at normal temperature under atmospheric pressure.

On the other hand, the mold foaming is a method of mixing and injecting raw materials for manufacturing polyurethane foam into a cavity of a mold (mould) and foaming into a shape of a molding cavity

[4. Effect ]

In the production of polyurethane foam, a polyurethane foam having low hardness, high rebound resilience and low compression set can be obtained by adding a monoalcohol C (ether-based high molecular weight monoalcohol) as a raw material.

The decrease in hardness is thought to be due to the fact that the proportion of the hard segment (urethane bond) in the polymer chain is moderately decreased by adding an appropriate amount of the monoalcohol C.

The improvement in rebound resilience or the reduction in compression set is thought to be due to the fact that the addition of a suitable amount of the monoalcohol C lengthens the terminal alkyl group, and the free long-chain alkyl group enhances intermolecular repulsion.

Examples

(Example 1 to 7, comparative example 1 to 9)

[1. Preparation of sample ]

[1.1. Raw materials ]

The following polyols were used:

(1) Polyol A, polyether polyol, weight average molecular weight 7000, number of functional groups 3, EO content 15.5% by mass, product name KC-737, sanyo chemical industry Co., ltd;

(2) Polyol B, polyether polyol, weight average molecular weight 3400, number of functional groups 3, EO content of 72% by mass, product name EP-505S, manufactured by Mitsui chemical Co., ltd;

(3) Polyol D, polyether polyol, weight average molecular weight 2000, number of functional groups 2, EO content 0% by mass, product name D-2000, manufactured by Sanjing chemical Co., ltd;

(4) Polyol E, polyether polyol, weight average molecular weight 750, number of functional groups 3, EO content 0% by mass, product name GP750NS, sanyo chemical industry Co., ltd.

The following monoalcohols were used:

(1) The monol C1 is polyether monol, the weight average molecular weight is 3000, the functional group number is 1, the EO content is 0 mass percent, the product name is ML-3000, manufactured by Mitsui chemical Co., ltd;

(2) The monol C2 is polyether monol, the weight average molecular weight is 5000, the functional group number is 1, the EO content is 0 mass percent, the product name is ML-5000, manufactured by Mitsui chemical Co., ltd;

(3) The monol F was polyether monol, the weight average molecular weight was 470, the number of functional groups was 1, the EO content was 0% by mass, and the product name was CA-120, manufactured by Mitsui chemical Co., ltd.

The following resinification catalysts, foam stabilizers, blowing agents and polyisocyanates were used.

(1) A resinification catalyst, which is 33% of triethylenediamine, and a product name, DABCO 33LSI, manufactured by Evonik Japan Co., ltd;

(2) Foam stabilizer, organosilicon foam stabilizer, product name B8742FL2, manufactured by Yingzhuang Japan Co., ltd;

(3) Foaming agent water

(4) Polyisocyanate, monomeric MDI (diphenylmethane diisocyanate), NCO content of 6%, product name: LUPRANATE (registered trademark) MI, manufactured by BASF Inoac polyurethane Co., ltd

Table 1 shows a list of raw materials used.

TABLE 1

[1.2 Foam formation ]

The above raw materials are mixed according to a prescribed proportion to obtain a raw material mixture. The raw material mixture was injected into a mold maintained at 65 ℃ and the raw material mixture was foamed in the mold. The mold was then placed in an oven set at 70 ℃ and the foam was cured.

[2. Test method ]

[2.1. Hardness ]

Asker F hardness was determined using Asker rubber durometer type F.

[2.2. Modulus of elasticity in rebound ]

The rebound elastic modulus was measured in accordance with JIS K6255.

[2.3 Compression set ]

Compression set was measured in accordance with JIS K6400-3. Wherein the compression ratio is set to 50% or 25% of the original thickness.

[2.4 Foam State ]

The presence or absence of bubbles Kong Cucao was evaluated by visual observation.

[3. Results ]

The results are shown in tables 2 and 3. Table 2 and table 3 show the raw material compositions of the respective samples together. The numerical value of the raw material composition represents parts by mass. The following can be seen from tables 2 and 3.

(1) The hardness of comparative examples 1 to 2 increases. The reason for this is considered to be that the existence ratio of the hard segment increases because the monoalcohols C1, C2 are not contained.

(2) The compression set of comparative example 3 increases. The reason for this is considered to be that since the low molecular weight of the monoalcohol F is used, the terminal alkyl chain becomes short and the cells become easily bonded.

(3) The hardness of comparative examples 4 and 5 increased, the rebound elastic modulus decreased, and the compression set increased. This is thought to be due to the low content of polyol A.

(4) The hardness of comparative example 6 was increased, and the compression set was also increased. The reason for this is considered to be that the air permeability is reduced by the absence of the polyol B.

(5) None of comparative examples 7-9 formed foam. The reason for this is considered to be that the content of the monoalcohol C2 is excessive, and thus the polymerization is insufficient, the raw material mixture is insufficiently thickened, and bubbles escape from the raw material mixture.

(6) Examples 1 to 7 each had a hardness of 35 or less, a rebound elastic modulus of 35% or more, and a compression set (50% compression) of 20% or less. Wherein cell roughening occurred in example 1. The reason for this is considered to be that the foam formation is unstable because the amount of polyol B added is slightly large, which has a high EO content.

(7) Example 6 has lower hardness, higher modulus of elasticity in rebound, and lower compression set than example 2. The reason for this is considered to be that by increasing the amount of polyol B, the air permeability is improved and the flexibility of the molecular skeleton is improved.

TABLE 2

TABLE 3

The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the present invention.

Industrial applicability

The polyurethane foam of the present invention can be used for clothing, sports goods, toys, bedding, interior trim, etc.

Claims

1. A polyurethane foam, wherein the polyurethane foam is obtained by foaming and reacting a raw material mixture comprising the following components:

Compounds having active hydrogen atoms; and

Polyisocyanates,

The compounds having active hydrogen atoms include:

More than 40.0% by mass of polyol A;

More than 0 mass % of polyol B; and

The monol C content is more than 0% by mass and less than 15.0% by mass.

in,

The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 3000 or more and an EO content of less than 50.0% by mass.

The "polyol B" is one or more polyether polyols having an EO content of 50.0% by mass or more.

The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more.

The “mass %” indicating the content of the polyol A, the polyol B or the monool C refers to the ratio of the mass of the polyol A, the polyol B or the monool C to the total mass of the compound having an active hydrogen atom.

2 . The polyurethane foam according to claim 1 , wherein the rebound elastic modulus is 35% or more.

Here, the “rebound elastic modulus” refers to a value measured in accordance with JIS K6255.

The polyurethane foam according to claim 1 , wherein the Asker F hardness is 35 or less.

The polyurethane foam according to claim 1 , wherein the compression set is 20% or less.

Here, the "compression set" refers to a value measured in accordance with JIS K6400-3 (50% compression).

5. A polyurethane foam, wherein:

Using monool C having a weight average molecular weight of 2000 or more as a raw material,

The rebound elastic modulus is more than 35%,

Asker F hardness is 35 or less.