JPH0791356B2 - Manufacturing method of flexible polyurethane foam - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyol composition for a flexible polyurethane foam and a method for producing a flexible polyurethane foam. More specifically, it has good moldability in a wide range of mold temperature (hereinafter simply referred to as mold temperature) from 35 ° C to 60 ° C when injecting urethane foaming liquid, and it produces polyurethane foam with soft foam hardness. And a method for producing a flexible polyurethane foam, which is suitable for use in molded polyurethane foams.

[Prior Art] As a method of reducing the hardness of polyurethane foam, CFC 11 is used, the number of functional groups of the polyol is reduced, and polyether polyol having a large oxyethylene portion is used (for example, Japanese Patent Publication Nos. 46-28793 and 46-28793). 58-3488, JP-B-53-13700, JP-B-56-43247 and JP-B-54-17360
No. gazette), and a method of increasing the mold temperature.

[Problems to be Solved by the Invention] However, these methods have advantages and disadvantages. That is, the method using chlorofluorocarbon has an environmental problem that the chlorofluorocarbon destroys the ozone layer, and the method of lowering the number of functional groups of the polyol increases the curing time of the foam and significantly deteriorates the compression set, which is not practical. poor. A method of molding a molded polyurethane foam by a one-shot method using a polyether polyol having many oxyethylene moieties, and a method of increasing the mold temperature have poor foaming stability and cause molding defects such as cracks. A molded article of polyurethane foam cannot be obtained.

[Means for Solving the Problems] The present inventors have solved these problems and have achieved a mold temperature of 35 ° C.
The present invention has been achieved as a result of extensive studies on a polyol composition and a method for producing a polyurethane foam suitable for producing a soft polyurethane foam having good moldability in a wide range of -60 ° C and a foam hardness.

That is, the present invention is a method for producing a polyurethane foam by reacting an organic polyisocyanate and a polyol in the presence of a catalyst, a foaming agent and a foam stabilizer, wherein the polyol has (a) a functional group number of 2 or more. , A polyether polyol having a molecular weight of 800 to 1700 per hydroxyl group,
(B) The number of functional groups is 3 or more, and the molecular weight per hydroxyl group is
A flexible polyurethane foam comprising a polyol composition comprising a polyether polyol having a molecular weight of 300 to less than 800 and (c) a monool having a molecular weight of 100 to 2000 and a content of (b) of 40 to 5% by weight. Is a manufacturing method.

Examples of the polyether polyol (a) used in the present invention include compounds having a structure in which an alkylene oxide is added to a compound having two or more active hydrogen atoms (for example, alcohols and amines).

Examples of alcohols include dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol and neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sorbitol. Examples include trihydric or higher alcohols such as sugar.

As amines, ammonia; mono-, di-, and alkanolamines such as triethanolamine, isopropanolamine, and aminoethylethanolamine;
C _{1 to} C ₂₀ alkylamines; C _{2 to} C ₆ alkylenediamines such as ethylenediamine and hexamethylenediamine; polyalkylenepolyamines such as diethylenetriamine and triethylenetetramine; aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline , Aromatic amines such as diphenyl ether diamine; alicyclic amines such as isophorone diamine and cyclohexylene diamine; aminoethylpiperazine,
Heterocyclic amines described in JP-B-55-21044 can be used. Two or more kinds of these active hydrogen atom compounds may be used in combination. Of these, alcohols are preferable.

The alkylene oxide to be added to the active hydrogen atom compound, ethylene oxide (hereinafter abbreviated as EO),
Propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,3
-, 1,4-, 2,3-butylene oxide and the like and a combination of two or more kinds thereof are preferable, and a combination of EO and PO is preferable, and an addition form may be block addition or random addition.

The number of functional groups of the polyol (a) is usually 2 or more, preferably
It is 2.5 to 4.0. When the number of functional groups is less than 2, the compression set becomes poor and the curing time becomes long.

The molecular weight per hydroxyl group of polyol (a) is usually 80.
It is 0 to 1700, preferably 900 to 1500. If the molecular weight per hydroxyl group is less than 800, foam collapses and the compression set deteriorates, and if it exceeds 1700, the compression set deteriorates and the curing time increases.

Examples of the polyether polyol (b) include a structure in which an alkylene oxide is added to a compound (for example, alcohols and amines) having 3 or more active hydrogen atoms.

Examples of alcohols include trihydric or higher alcohols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol and sucrose.

As amines, ammonia; mono-, di-, and alkanolamines such as triethanolamine, isopropanolamine, and aminoethylethanolamine;
C ₂ such as ethylenediamine and hexamethylenediamine
C ₆ alkylenediamine; polyalkylenepolyamines such as diethylenetriamine and triethylenetetramine; aromatic amines such as aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline and diphenyletherdiamine; oils such as isophoronediamine and cyclohexylenediamine Cyclic amines;
Examples thereof include aminoethylpiperazine and heterocyclic amines described in JP-B-55-21044. Two or more kinds of these active hydrogen atom compounds may be used in combination. Of these, alcohols are preferable.

Examples of the alkylene oxide to be added to the active hydrogen atom compound include EO, PO, 1,2-, 1,3-, 1,4-, 2,3-butylene oxide and the like, and combinations of two or more thereof. , EO and PO are preferably used in combination, and the addition format may be block addition or random addition.

The number of functional groups of the polyol (b) is usually 3 or more, preferably
It is 3.0 to 6.0. If the number of functional groups is less than 3, the compression set will be poor.

The molecular weight per hydroxyl group of polyol (b) is usually 30.
It is 0 to 800, preferably 400 to 700. If the molecular weight per hydroxyl group is less than 300, the foam will collapse, and if it exceeds 800, the compression set will be poor.

Examples of the monool (c) include compounds having a structure in which an alkylene oxide is added to a hydrocarbon alcohol or phenol having one active hydrogen atom. Of these, preferred are compounds having a structure in which alkylene oxide is added to hydrocarbon alcohol.

Hydrocarbon alcohols include monohydric alcohols having 1 to 18 or more carbon atoms (eg, aliphatics such as methanol, ethanol, n- and iso-propanol, butanol, 2-ethylhexyl alcohol, cyclohexanol and benzyl alcohol, alicyclic rings). Formula and aromatic alcohol)
Etc.

Examples of phenols include monohydric phenols (eg, alkylphenols such as phenol and nonylphenol).

Examples of the alkylene oxide to be added to the active hydrogen atom compound include EO, PO, 1,2-, 1,4-, 2,3-butylene oxide and the like, and a combination of two or more thereof.
EO and PO are preferable, and the addition format may be either block or random.

The molecular weight of the monool (c) is usually 100 to 200, preferably
400 to 1600. When the molecular weight is less than 100, the foam collapses, and when it exceeds 2000, the foam hardness, which is the object of the present invention, does not become soft, and when the mold temperature is raised (45 ° C to 60 ° C).
℃), loose skin and cracks occur in the molded foam.

The polyol composition of the present invention comprises the above (a), (b) and (c). Each amount is usually 40-95%, preferably 50-80% of (a) based on the total polyol composition weight.
%, (B) is usually 40 to 5%, preferably 35 to 10%,
(C) is usually 20 to 0.1%, preferably 15 to 3%.
If (a) is less than 40%, the impact resilience and compression set will be poor, and if it exceeds 95%, the moldability will be poor and the foam hardness will be less likely to be soft. If (b) is less than 5%, the compression set will be poor, and if it exceeds 40%, cracks will appear and the impact resilience will be poor. If the content of (c) is less than 0.1%, the foam hardness is less likely to be soft, cracks occur when the mold temperature is raised, and if it exceeds 20%, the compression set becomes poor and the curing property becomes poor.

A polymer polyol composition comprising the polyol composition of the present invention and a vinyl monomer polymer also belongs to the present invention.

The polymer polyol composition is the polymer polyol composition in at least one of the above (a), (b) and (c) in the presence of a radical initiator,
Acrylonitrile, a vinyl monomer such as styrene is polymerized and stably dispersed, and the content of the vinyl polymer in the polymer polyol is based on the total weight of the polymer polyol.
It is usually 45% or less, preferably 30% or less.

The present invention also includes a method for producing a flexible polyurethane foam by reacting an organic polyisocyanate with the above polyol composition and / or polymer polyol composition in the presence of a catalyst, a foaming agent and a foam stabilizer. That is,
The polyol composition of the present invention and the polymer polyol composition may be used alone or in combination.

As the organic polyisocyanate used in the present invention, those generally used for polyurethane are used. For example, aromatic polyisocyanate having 6 to 20 carbon atoms (excluding carbon atoms in NCO group) [2,4-, 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'-, 4,4 ′ -Diphenylmethane diisocyanate (MDI), crude MDI [crude diaminophenylmethane {condensation product of formaldehyde and aromatic amine (aniline) or a mixture thereof; diaminodiphenylmethane and a small amount (for example, 5 to 20% by weight) of trifunctional or more. A polyisocyanate obtained by phosgenation of a mixture with a polyamine of (1); polyaryl polyisocyanate (PAPI)] and the like; aliphatic isocyanate having 2 to 18 carbon atoms [hexamethylene diisocyanate, lysine diisocyanate, etc.]; Alicyclic polyisocyanates (isophorone diisocyanate, dicyclohexyl diisocyanate, etc. Aroaliphatic polyisocyanates having 8 to 15 carbon atoms [such as xylylene diisocyanate]; modified products of these polyisocyanates (urethane group, carbodiimi group, allophanate group, urea group, buret group, uretdione group, uretonimine group, isocyanurate) Group, oxazolidone group-containing modified product, etc.); polyisocyanates other than the above described in Japanese Patent Application No. 59-199160; and mixtures of two or more thereof. and
2,6-TDI and mixtures of these isomers.

As the foam stabilizer, those for soft urethane foam are usually used. Examples thereof include dimethyl siloxane-based foam stabilizers, and specifically, L-54 manufactured by Nippon Unicar Co., Ltd.
0, SH-190 and SRX-194A manufactured by Toray Silicon Co., Ltd.

Known catalysts can be used. Specifically, as a trimerization catalyst, a metal salt of carboxylic acid (such as sodium acetate);
Alkali and alcal earth metal alkoxides and phenoxides (eg sodium methoxide, sodium phenoxide etc.); tertiary amines (eg triethylamine, dimethylaminomethylphenol); quaternary ammonium salts (eg tetraethylammonium hydroxide etc.) and the like. As a urethane-forming catalyst, a metal salt of a carboxylic acid (eg, lead octylate, zinc octylate, cobalt naphthenate, etc.); a tertiary amine (eg, triethylenediamine, N-methylmorpholine, pyridine, etc.); imidazoles (eg, imidazole, 2-ethyl-4-methylimidazole);
Examples thereof include organic metal compounds such as tin and antimony (eg, tetraphenyl tin, tributyl antimony oxide, stanna octoate, etc.). Of these, preferred are organometallic compounds such as tin and antimony, and tertiary amines.

As the foaming agent, those usually used for polyurethane foams can be used, and water alone or a combination of water and methylene chloride is preferable, and water alone is preferable, and according to the present invention, the foam hardness is soft without using CFCs. If a product that can be obtained but is softer in hardness is required, CFC can be used together.

In the production method of the present invention, when the polyol composition and the polymer polyol composition are used in combination, when the total amount of both is 100 parts by weight, the amount of the polymer polyol composition used is usually 50.
It is not more than 20 parts, preferably not more than 20 parts.

In the present invention, the amount of each additive (foaming agent, foam stabilizer and catalyst) used is as follows based on 100 parts by weight of the polyol.

The amount of foaming agent used is not particularly limited, but in the case of water, it is usually 2
-8 parts, preferably 3-7 parts. The amount of the foam stabilizer used is usually 0.5 to 5 parts, preferably 1 to 3 parts. The amount of the catalyst used is usually 0.01 to 3 parts, preferably 0.05 to 2 parts.

The amount of isocyanate used is usually 70 to 120 as NCO index,
It is preferably 80 to 110.

The flexible polyurethane foam of the present invention can be produced by a so-called slab, hot cure or cold cure method. Among them, the slab and hot cure methods are preferable, and the hot cure method is particularly preferable.

In the hot cure method, it has good moldability in a wide range of mold temperature of 35 to 60 ° C, and the mold temperature can be selected according to the desired density and manufacturing conditions.

[Examples] The present invention is further described below with reference to examples, but the present invention is not limited thereto.

Examples 1 to 6 and Comparative Examples 1 to 2 With the foaming formulation shown in Tables 1 and 2 (the numbers in the table indicate parts by weight), urethane foam was foamed in a mold, and then the urethane foam was molded into a metal mold. The flexible polyurethane foam was taken out from the mold and its physical properties were measured.

(Foaming condition) Mold shape: 300mm × 300mm × 100mm Material: Aluminum Mold temperature: 35-60 ℃ Mixing method: Low pressure machine mixing Raw material temperature: 25 ± 2 ℃ Cure condition: 150 ℃ × 10 minutes (raw material) Polyol (A) -1: PO-EO adduct of glycerin, molecular weight 3000.

Polyol (b): PO adduct of pentaerythritol,
Molecular weight 2000.

PO-EO adduct of monool (c) -1: n-butanol, molecular weight 600.

Monool (c) -2: n-butanol PO-EO adduct, molecular weight 1200.

T-80: Nippon Polyurethane Co., 2-4 / 2-6 Tolylene diisocyanate 80/20 mixture Polymer polyol composition 1 (abbreviated as P-1): Azo in 80 parts of the above polyol (a) -1 Polymerized by dispersing 16 parts of acrylonitrile and 4 parts of styrene in the presence of 1 part of bisisobutyronitrile.

The abbreviations in the table are as follows.

DABCO33LV: Triethylenediamine 33% dipropylene glycol solution SRX-294A: Toray Silicone Co., Ltd. dimethylsiloxane foam stabilizer Foam measurement method is JIS K6401, the unit is core density …… kg / m ³ 25% ILD… … Kg / 314cm ² Compression set …… (%) Rebound resilience …… (%).

The moldability was visually observed for the presence of loose skin and cracks.

[Effects of the Invention] By using the polyol composition for a flexible polyurethane foam of the present invention, only water is used without using a low-boiling halogenated hydrocarbon blowing agent such as Freon 11 which is indispensable in conventional polyether polyols. It can be used as a foaming agent to obtain a soft polyurethane foam having the same foam hardness as conventional ones, and can also solve the problem of environmental damage to the earth. Also, even at a mold temperature of 45 ° C or higher,
It is possible to produce a soft polyurethane foam having good moldability, low density and foam hardness.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 75:08 (56) Reference JP-A-2-163112 (JP, A) JP-A-56- 67330 (JP, A) JP 60-219220 (JP, A) Keiji Iwata, "Polyurethane Resin Handbook," September 25, 1987, published by Nikkan Kogyo Shimbun, pp. 156-159.

Claims (1)

[Claims] 1. An organic polyisocyanate and a polyol are reacted in the presence of a catalyst, a foaming agent and a foam stabilizer,
In the method for producing a polyurethane foam, the polyol is (a) a polyether polyol having 2 or more functional groups and a molecular weight per hydroxyl group of 800 to 1700,
(B) The number of functional groups is 3 or more, and the molecular weight per hydroxyl group is
A flexible polyurethane foam comprising a polyol composition comprising a polyether polyol having a molecular weight of 300 to less than 800 and (c) a monool having a molecular weight of 100 to 2000 and a content of (b) of 40 to 5% by weight. Manufacturing method.