JP3630646B2 - Production method of polyurethane foam - Google Patents

Description

【００６４】
表１に示された結果から、各実施例で得られたポリウレタンフォームには、特定の非イオン性化合物が用いられているので、いずれのポリウレタンフォームも、鋼球の反発が小さく、低反発性を有するものであることがわかる。更に、各実施例で得られたポリウレタンフォームは、セル形態が良好であり、しかもフォーム感触にも優れたものであることがわかる。
【００６５】
【発明の効果】
本発明のポリウレタンフォームの製造法によれば、ポリウレタンフォームの形成段階でセルが微細化するとともに、安定化するので、均質でセル径の小さいポリウレタンフォームを得ることができる。また、このポリウレタンフォームは、低反発特性を有し、セル形状の微細化、均質化による効果と相まってスライシング等の加工性にも優れたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polyurethane foam. More specifically, the present invention relates to a method for producing a flexible polyurethane foam that can be suitably used for automobile interior materials, bedding, furniture and the like.
[0002]
[Prior art]
Since flexible polyurethane foam has good elastic properties, it is used as a cushioning material for automobile interior materials, bedding, furniture and the like. In the production of this polyurethane foam, the polyol component and the isocyanate compound are mixed and reacted to improve the compatibility of the raw material compound of the polyurethane foam and to homogenize and stabilize the cells of the obtained polyurethane foam. It has been proposed to add a nonionic surfactant to the starting compound (Japanese Patent Laid-Open No. 48-18396). Among nonionic surfactants, for example, when an ethylene oxide adduct of nonylphenol is used, the compatibility between the polyol component and the isocyanate compound is improved, and the cells of the polyurethane foam are homogeneous and stabilized and have good characteristics. A polyurethane foam is obtained.
[0003]
However, since ethylene oxide adducts of nonylphenol may adversely affect the human body, there is a need to reduce the amount used.
[0004]
It is also known to use a nonionic surfactant or an anionic surfactant such as a polyalkylene glycol having a relatively low molecular weight or an ethylene oxide adduct of an alkyl alcohol described in the above publication in the production of polyurethane foam. However, there is a drawback that it is insufficient in terms of improving the reactivity and homogenizing the cell.
[0005]
In recent years, there has been an increasing demand for polyurethane foam interior cushioning materials that have low resilience characteristics in view of automobile crash safety. Polyurethane foam manufacturers have intensively studied the selection of raw materials used and various additives. However, those having sufficient low resilience characteristics have not been obtained. In particular, when an ether-based polyol is used, it has not been obtained that has sufficiently low rebound characteristics.
[0006]
[Problems to be solved by the invention]
The present invention improves the compatibility between the polyol component and the isocyanate compound without using a compound that may adversely affect the human body, achieves homogenization and stabilization of the cell, and has a low resilience characteristic It is an object of the present invention to provide a manufacturing method for the above.
[0007]
[Means for Solving the Problems]
That is, the gist of the present invention is as follows.
(1) A polyol component and an isocyanate compound are represented by the formula (I):
RO-[(EO) _x. (PO) _y ]-(EO) _z- H (I)
[Wherein, R represents a linear or branched alkyl group or alkenyl group having 8 to 20 carbon atoms, EO represents an oxyethylene group, and PO represents an oxypropylene group. x and z each represent an average addition mole number of oxyethylene groups of 1 or more, and the sum of x and z is 3 or more. y is 1 or more which shows the average addition mole number of an oxypropylene group. The addition form of [(EO) _x · (PO) _y ] is random addition, block addition, or a mixture addition thereof, and [(EO) _x · (PO) _y ] and (EO) _z are block combinations. doing〕
And a polyurethane foam having a nonionic compound represented by formula (I) as a structural unit, and a polyurethane foam having a nonionic compound represented by formula (I) as a structural unit. .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The polyol component is not particularly limited as long as it is conventionally used when producing a polyurethane foam. Examples of the polyol component include polyester polyols and polyether polyols having 2 to 8 functional groups.
[0009]
The polyester polyol can be produced by a condensation reaction of a dicarboxylic acid and a polyhydric alcohol.
[0010]
Examples of the dicarboxylic acid used in the polyester polyol include saturated aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid; saturated aliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; phthalic acid, Aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid; halogen-containing dicarboxylic acids such as tetrabromophthalic acid; these ester-forming derivatives, these acids An anhydride etc. are mentioned, These can be used individually or in mixture of 2 or more types. The dicarboxylic acid may optionally contain a tribasic or higher polybasic acid such as trimellitic acid or pyromellitic acid.
[0011]
Examples of the polyhydric alcohol constituting the polyester polyol include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexane. Examples include diol, trimethylolpropane, glycerin, pentaerythritol, diglycerin, dextrose, sorbitol, and the like. These can be used alone or in admixture of two or more.
[0012]
Representative examples of the polyether-based polyol include polyoxyalkylene polyol, polyoxytetramethylene glycol, and mixtures thereof.
[0013]
A polyoxyalkylene polyol is a compound having two or more active hydrogen-containing groups as a starting material compound, and is an alkylene oxide such as ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, and styrene oxide. It can be produced by a cycloaddition reaction.
[0014]
Examples of the compound having two or more active hydrogen-containing groups include divalent alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, and 1,6-hexanediol; Trihydric or higher polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, diglycerin, dextrose, sorbitol, sucrose; polyhydric phenols such as resorcinol, hydroquinone, bisphenol A; ethylenediamine, tolylenediamine, 1,3-propane Examples include polyamines such as diamine and isophoronediamine; alkanolamines such as diethanolamine and triethanolamine, and modified products thereof. These may be used alone or in combination of two or more. It can be used.
[0015]
Polyoxytetramethylene glycol can be produced by ring-opening polymerization of tetrahydrofuran.
[0016]
As a polyol component, the said polyester-type polyol and polyether-type polyol can be used individually or in mixture of 2 or more types.
[0017]
Since the number of functional groups and the hydroxyl value of the polyol component vary depending on the required physical properties of the polyurethane foam, it cannot be determined unconditionally. Representative examples of the polyol component include polyols having 2 to 4 functional groups and a hydroxyl value of 10 to 250.
[0018]
As isocyanate compounds, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate Aromatic polyisocyanates such as xylylene diisocyanate and naphthylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate and isophorone diisocyanate; urethane Bond, carbodiimide bond, uretimine bond, allophanate bond, urea bond, burette bond, The polyisocyanate modified product, and the like containing isocyanurate bond one or more, and these may be used alone or in admixture of two or more.
[0019]
The ratio of the polyol component and the isocyanate compound is usually preferably adjusted so that the isocyanate index is 80 to 160, preferably 90 to 120.
[0020]
The reaction between the polyol component and the isocyanate compound is performed in the presence of a nonionic compound represented by the formula (I), a foaming agent and a catalyst.
[0021]
In the nonionic compound represented by the formula (I), R represents a linear or branched alkyl group or alkenyl group having 8 to 20 carbon atoms, and these groups may be used alone or in combination of two or more. It can be used by mixing. Among R, an alkyl group having 8 to 18 carbon atoms is preferable from the viewpoints of the surface active effect, oxidation resistance stability, and economical efficiency (low cost and easy availability).
[0022]
EO represents an oxyethylene group. PO represents an oxypropylene group. x and z are each a number of 1 or more indicating the average number of moles added of the oxyethylene group, but x is a number from 1 to 10 and z is 1 from the viewpoint of the surface active effect, room temperature properties and handling viscosity. It is preferably a number of ˜20, more preferably x is a number of 1 to 5 and z is a number of 1 to 10. Although the sum of x and z is 3 or more, the number of 3-20 is preferable and the number of 3-10 is more preferable from the viewpoint of homogenization and stability of the cells of the polyurethane foam.
[0023]
y is 1 or more which shows the average addition mole number of an oxypropylene group, However, The number of 1-10 is preferable from a viewpoint of surface active effect and handling viscosity, and the number of 1-7 is more preferable.
[0024]
The above-mentioned “mixed addition” refers to an addition form in which random addition and block addition are added at an arbitrary ratio.
[0025]
In the nonionic compound represented by the formula (I), R is an alkyl group having 8 to 18 carbon atoms, x is a number of 1 to 10, y is a number of 1 to 10, and z is a number of 1 to 20. It is preferable from the viewpoint of the surface active effect on the polyol component and the isocyanate compound and the handling property of the nonionic compound.
[0026]
Representative examples of suitable nonionic compounds include those of formula (Ia):
RO- (EO) _x- (PO) _y- (EO) _z- H (Ia)
[Wherein, R, EO, PO, x, y and z are the same as above. (EO) _x , (PO) _y and (EO) _z are block-bonded according to this order.]
The nonionic compound represented by these is mentioned.
[0027]
The amount of the nonionic compound represented by the formula (I) is 5 to 20 parts by weight with respect to 100 parts by weight of the polyol component from the viewpoint of miniaturization of polyurethane foam cells, homogenization and expression of low resilience characteristics. The amount is preferably 8 to 15 parts by weight.
[0028]
The nonionic compound may be mixed with the polyol component in advance before the reaction between the polyol component and the isocyanate compound, or mixed with a catalyst and a foam stabilizer or other auxiliary agent that can be used as necessary. May be.
[0029]
Examples of the blowing agent include water, low-boiling hydrocarbons such as isopentane, normal pentane, and cyclopentane, gases such as nitrogen gas, air, and carbon dioxide, methylene chloride, HCFC-141b, HCFC-142b, HCFC-22, and HFC-134a. , HFC-152a, HFC-245fa, HFC-245ca, HFC-236ea, HFC-365mfc and the like, and these can be used alone or in admixture of two or more. Among these, water is preferable from the viewpoint of environmental protection.
[0030]
Since the amount of the foaming agent varies depending on the type and density of the target polyurethane foam, it cannot be determined unconditionally. Therefore, it is desirable to adjust appropriately according to these.
[0031]
Examples of the catalyst include 1,4-diazabicyclo [2.2.2] octane, 2-methyl-1,4-diazabicyclo [2.2.2] octane, N-methylmorpholine, N-ethylmorpholine, N- (dimethyl Aminoethyl) morpholine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N-dimethylpiperazine, N, N ′, N′-trimethylaminoethylpiperazine, tris (3-dimethylaminopropyl) amine, N, N-dimethylcyclohexylamine, N, N-dimethylbenzylamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, bis (2-dimethylaminoethyl) ether, 1,8-diazabicyclo [ .4.0] undecene -7, N, N ', N "- tris (3-dimethylaminopropyl) hexahydro -s- triazine,
[0032]
6-dimethylamino-1-hexanol, 5-dimethylamino-3-methyl-1-pentanol, N, N-dimethylethanolamine, N, N-dimethylaminoethoxyethanol, N, N-dimethylaminoethoxyethoxyethanol, N- (3-dimethylaminopropyl) -N-methylaminoethanol, N- (2-dimethylaminoethyl) -N-methylaminoethanol, 1-methylimidazole, 1-isobutyl-2-methylimidazole, 1,2- Tertiary amine catalysts such as dimethylimidazole and their derivatives, salts of these with acids such as carboxylic acid and carbonic acid; organic typified by organotin compounds such as tin dibutyldiacetate, tin dioctanoate, tin dibutyldilaurate A metal compound etc. are mentioned.
[0033]
The amount of the catalyst cannot be determined unconditionally because the reaction mechanism and reaction characteristics differ depending on the type of the catalyst, and therefore it is desirable to appropriately adjust the amount according to the type.
[0034]
When producing a polyurethane foam, a foam stabilizer can be used as necessary.
[0035]
Any foam stabilizer may be used as long as it is generally used when producing a polyurethane foam. Examples of the foam stabilizer include silicone surfactants such as dimethylpolysiloxane and polyoxyalkylene-modified dimethylpolysiloxane, and anionic surfactants such as fatty acid salts, sulfate ester salts, phosphate ester salts, and sulfonate salts. It is done.
[0036]
Since the amount of the foam stabilizer varies depending on the type and characteristics of the target polyurethane foam and cannot be determined unconditionally, it is desirable to adjust appropriately according to these.
[0037]
In addition to the above components, other auxiliary agents can be used as necessary.
Examples of other auxiliaries include cross-linking agents, stabilizers, pigments, flame retardants, fillers, and the like, and these can be used within a range that does not impair the object of the present invention.
[0038]
Examples of the crosslinking agent include a low molecular weight compound having two or more active hydrogen-containing groups capable of reacting with a hydroxyl group, a first amino group, a second amino group, and other isocyanate groups. Examples include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolpropane, triethanolamine, alkylene oxide of bisphenol A. Examples include polyhydric alcohols such as adducts, polyamines such as diethyltoluenediamine, chlorodiaminobenzene, ethylenediamine, and 1,6-hexanediamine. These can be used alone or in admixture of two or more.
[0039]
Examples of the stabilizer include dibutylhydroxytoluene, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], isooctyl-3- (3,5-di-t-butyl). -4-hydroxyphenyl) propionate and other hindered phenol radical scavengers; antioxidants such as phosphorous compounds such as phosphorous acid, triphenyl phosphite, triethyl phosphite, triphenyl phosphine; 2- (5 -Methyl-2-hydroxyphenyl) benzotriazole, methyl-3- [3-t-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] condensate of propionate and polyethylene glycol, etc. UV absorbers and the like, and these may be used alone or in combination of two or more. It can be used by mixing. Among these stabilizers, phosphite compounds, especially triphenyl phosphite and pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] are foam strengths. From the viewpoint of improvement, it can be preferably used. Particularly when triphenyl phosphite and pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] are used in combination, the foam strength is further increased. There is an advantage that can be.
[0040]
Examples of the pigment include inorganic pigments typified by transition metal salts, organic pigments typified by azo compounds, carbon powder, and the like. These pigments can be used alone or in admixture of two or more.
[0041]
Examples of the flame retardant include halogen-based flame retardants such as tris (chloropropyl) phosphate, tris (dichloropropyl) phosphate, and tris (chloroethyl) phosphate.
[0042]
Examples of the filler include inorganic compounds such as silica-based fine particles and alumina-based fine particles, and organic compounds such as melamine-based resins and phenol-based resins.
[0043]
The polyurethane foam can be produced by reacting a polyol component and an isocyanate compound in the presence of a nonionic compound, a foaming agent and a catalyst, if necessary, a foam stabilizer, and other auxiliary agents.
[0044]
The polyurethane foam, for example, a polyol component, a nonionic compound, a foaming agent, a catalyst and, if necessary, a foam stabilizer and other auxiliary agents are mixed, and the resulting polyol mixture and an isocyanate compound are mixed with a molding machine or the like. It can be molded by mixing, stirring, pouring into a mold and foaming. More specifically, for example, after the temperature of the polyol mixture is adjusted to about 20 ° C. using a tank or the like, the isocyanate component is mixed with an isocyanate component using a foaming machine such as an automatic mixing injection type foaming machine or an automatic mixing injection type foaming machine. By reacting, a polyurethane foam can be produced.
[0045]
As described above, according to the production method of the present invention, since a specific nonionic compound is used, the compatibility between the polyol component and the isocyanate compound is improved, and the cell is fine in the polyurethane foam formation stage. Therefore, it is possible to obtain a polyurethane foam that is homogeneous and has a small cell diameter.
[0046]
Furthermore, the polyurethane foam containing the specific nonionic compound of the present invention is characterized in that the foam feel is good because the skin layer is thin and has low resilience. Further, due to these cell shape and foam physical property factors, the polyurethane foam also exhibits a secondary effect that it is excellent in processability to various shapes such as slicing.
[0047]
【Example】
Examples 1-6 and Comparative Examples 1-3
A polyol component, a nonionic compound, a foaming agent, a catalyst, and a foam stabilizer were mixed at a ratio shown in Table 1 with a lab mixer to obtain a polyol mixture.
[0048]
Next, the obtained polyol mixture and an isocyanate compound [a mixture of 80% by weight of 2,4-tolylenediamine and 20% by weight of 2,6-tolylenediamine; manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Sumijoule T-80, NCO 48%] was mixed and stirred with a lab mixer at 23 ° C. so that the isocyanate index was 105, and 250 g of the resulting mixture was molded into a mold [inner dimensions: 150 mm × 150 mm × 300 mm (height)] The polyurethane foam free form was molded.
[0049]
In addition, each used raw material compound is as follows.
[Polyol component]
Product name: Polyol MN-3050ONE, trifunctional polyol, molecular weight: 3000, hydroxyl value: 56 KOHmg / g, manufactured by Mitsui Chemicals, Inc.
[0050]
[Nonionic compounds]
REPE-1: Compound in formula (I), wherein R is an alkyl group having 12 carbon atoms, X is 2.0, Y is 2.0, and Z is 3.0. REPE-2: In formula (I), R Is an alkyl group having 14 carbon atoms, X is 2.0, Y is 2.0, and Z is 3.0. Compound REPE-3: In the formula (I), R is an alkyl group having 8 carbon atoms, and X is 3 Compound REPE-4 in which 0.0, Y is 1.0, and Z is 5.0: In the formula (I), R is an alkyl group having 16 carbon atoms, X is 6.0, Y is 5.0, and Z is Compound which is 6.0
Emulgen 908: Polyoxyethylene (8) nonylphenyl ether, manufactured by Kao Corporation, trade name: Emulgen 908
Diol400: Polypropylene glycol, manufactured by Mitsui Chemicals, Inc., trade name: Diol400, bifunctional polyol, molecular weight: 400, hydroxyl value: 280 KOHmg / g
[0052]
[Foaming agent]
Water [0053]
〔catalyst〕
Tin catalyst [tin dioctoate, manufactured by Sankyo Air Products Co., Ltd., trade name: DABCOT-9]
[0054]
Amine catalyst, KL-31: 1,4-diazabicyclo [2.2.2] octane 33.3% by weight dipropylene glycol solution, manufactured by Kao Corporation, trade name: Kao Raiser No. 31
KL-12: Dipropylene glycol solution containing 70% by weight of bis (2-dimethylaminoethyl) ether, manufactured by Kao Corporation, trade name: Kao Riser No. 12
[0055]
[Foam stabilizer]
Silicone foam stabilizer [made by Nippon Unicar Co., Ltd., trade name: L-580]
[0056]
Next, the physical properties of the obtained polyurethane foam were examined according to the following method. The results are shown in Table 1.
[0057]
1. A free form of steel ball rebound polyurethane foam was manufactured and allowed to stand for 1 day. Then, the polyurethane foam was cut into a central portion (core surface) of 150 mm × 150 mm × 50 mm (thickness) perpendicular to the foaming direction. The rebound height (mm) of the steel ball when a steel ball having a diameter of 20 mm was dropped from a position having a height of 300 mm was measured.
[0058]
2. Cell morphology (cell homogeneity and cell size)
A scanning electron micrograph (magnification: 20 times) of the cell of the polyurethane foam was observed, and the polyurethane foam (polyurethane foam containing no nonionic compound) obtained in Comparative Example 1 was used as a reference foam (Evaluation: Δ ), And the cell form (cell homogeneity and cell size) was evaluated based on the following evaluation criteria.
[0059]
[Evaluation criteria for cell homogeneity]
○: The cells of the polyurethane foam are more homogeneous than the reference foam.
(Triangle | delta): The cell of a polyurethane foam is equivalent to a reference | standard foam.
X: The cell of polyurethane foam is more heterogeneous than the reference foam.
[0060]
[Evaluation criteria for cell size]
○: The cell size of the polyurethane foam is finer than that of the reference foam.
(Triangle | delta): The cell size of a polyurethane foam is equivalent to a reference | standard foam.
X: The cell size of the polyurethane foam is larger than that of the reference foam.
[0061]
3. Foam feel The feel when the polyurethane foam was pushed by hand was evaluated based on the following criteria.
[0062]
〔Evaluation criteria〕
○: The resilience of the polyurethane foam is small (the foam is difficult to return to its original shape even if the hand is released)
X: The resilience of the polyurethane foam is large (the foam returns to its original shape when the hand is released)
[0063]
[Table 1]

[0064]
From the results shown in Table 1, since the specific nonionic compound is used for the polyurethane foam obtained in each example, each polyurethane foam has low repulsion of steel balls and low resilience. It turns out that it is what has. Furthermore, it can be seen that the polyurethane foam obtained in each example has a good cell shape and excellent foam feel.
[0065]
【The invention's effect】
According to the method for producing a polyurethane foam of the present invention, the cells are refined and stabilized in the formation stage of the polyurethane foam, so that a polyurethane foam having a uniform and small cell diameter can be obtained. Further, this polyurethane foam has low resilience characteristics and is excellent in workability such as slicing in combination with the effect of finer and homogenized cell shape.

Claims (5)

A polyol component and an isocyanate compound are represented by the formula (I):
RO-[(EO) _x. (PO) _y ]-(EO) _z- H (I)
[Wherein, R represents a linear or branched alkyl group or alkenyl group having 8 to 20 carbon atoms, EO represents an oxyethylene group, and PO represents an oxypropylene group. x and z each represent an average addition mole number of oxyethylene groups of 1 or more, and the sum of x and z is 3 or more. y is 1 or more which shows the average addition mole number of an oxypropylene group. The addition form of [(EO) _x · (PO) _y ] is random addition, block addition, or a mixture addition thereof, and [(EO) _x · (PO) _y ] and (EO) _z are combined in blocks. doing〕
A process for producing a polyurethane foam in which the reaction is carried out in the presence of a nonionic compound, a foaming agent and a catalyst. In the nonionic compound represented by the formula (I), R is an alkyl group having 8 to 18 carbon atoms, x is a number of 1 to 10, y is a number of 1 to 10, and z is a number of 1 to 20. A process for producing the polyurethane foam according to claim 1. The process according to claim 1 or 2, wherein the amount of the nonionic compound represented by the formula (I) is 5 to 20 parts by weight with respect to 100 parts by weight of the polyol component. The nonionic compound represented by the formula (I) is represented by the formula (Ia):
RO- (EO) _x- (PO) _y- (EO) _z- H (Ia)
[Wherein, R, EO, PO, x, y and z are the same as above. (EO) _x , (PO) _y and (EO) _z are block-bonded according to this order.]
The production method according to any one of claims 1 to 3, which is a nonionic compound represented by the formula: Formula (I):
RO-[(EO) _x. (PO) _y ]-(EO) _z- H (I)
[Wherein, R represents a linear or branched alkyl group or alkenyl group having 8 to 20 carbon atoms, EO represents an oxyethylene group, and PO represents an oxypropylene group. x and z each represent an average addition mole number of oxyethylene groups of 1 or more, and the sum of x and z is 3 or more. y is 1 or more which shows the average addition mole number of an oxypropylene group. The addition form of [(EO) _x · (PO) _y ] is random addition, block addition, or a mixture addition thereof, and [(EO) _x · (PO) _y ] and (EO) _z are combined in blocks. doing〕
The polyurethane foam which uses the nonionic compound represented by these as a structural unit.