JPH08245746A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE: To obtain a polyurethane foam which is useful as a cushion for furniture without cracking of the molded products on crushing and without shrinkage or adverse effect on resilience caused by insufficient crushing. CONSTITUTION: This foam is obtained by using (A) a diphenylmethane polyisocyanate such as tolylene diisocyanate as a polyisocyanate, (B) a polyoxyethylene-polyoxypropylene-polyol having 2 or more functional groups as those of a long-chain polyol and a molecular weight of 3,500-10,000 and containing 5-30 mole % of terminal oxyethylene, (C) 0.5-10wt.%, based on the polyol component (B), of a polyoxyethylene-polypropylene-polyol having 2-6 functional groups on the average as those of a foam breaker, and 800-5,000 OH equivalent and containing 3-20 mole % of terminal oxyethylene, and 65-90 mole % of randomly polymerized oxyethylene, and water as a foaming agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyurethane foam, and particularly to increasing the open cell ratio of a cold cure mold molded product, facilitating the crushing work of the molded product or eliminating the need for the crushing work. The present invention relates to a method for producing flexible polyurethane foam and semi-rigid polyurethane foam having open cells having flexibility and elasticity.

[0002]

2. Description of the Related Art Conventionally, flexible polyurethane foam has been widely used for furniture, bedding, vehicles, etc., particularly cushioning materials for automobiles, by taking advantage of its excellent cushioning property. As a method for producing the cushion material made of this flexible polyurethane foam, a method is known in which water and a low-boiling fluorine compound such as Freon 11 or Freon 123 are used in combination as a foaming agent. Further, in the production of foam, a seat cushion for automobiles or the like is mainly formed by a molding method.

[0003]

Generally, a molded product obtained by the cold cure molding method has a low open cell rate, and if left as it is, it shrinks and the cushioning performance also deteriorates. In order to eliminate these problems,
Crushing is performed to forcibly destroy the cell membrane and increase the open cell rate. Crushing methods include a roller crushing method and a vacuum crushing method.However, if the open cell ratio is low, the cell membrane may not be sufficiently destroyed. At the time of lashing, the cell skeleton was cracked and the molded product was sometimes broken. In addition, when foaming with water alone without using a low boiling point fluorine compound, physical properties such as impact resilience and compression set of the obtained flexible polyurethane foam are deteriorated, cushioning property and durability are impaired, and practicability It was difficult to obtain a foam with

[0004]

Means for Solving the Problems As a result of intensive research and study to solve these problems, the present inventors have made it possible to facilitate a crushing operation by combining a specific polyol and an isocyanate, and As a result, the inventors have found a method for producing a flexible or semi-rigid polyurethane foam having good foam physical properties such as impact resilience and compression set even when used alone as water, and completed the present invention.

That is, in the method for producing a polyurethane foam according to the present invention, tolylene diisocyanate and diphenylmethane type polyisocyanate are used together as (A) polyisocyanate, and (B) long-chain polyol having 2 or more functional groups and molecular weight. Using polyoxyethylene polyoxypropylene polyol with 3 to 30 mol% of terminal oxyethylene added at 3500 to 10,000, (C)
As a foam breaking agent, the average number of functional groups is 2 to 6, the hydroxyl equivalent is 800 to 5000, and oxyethylene is 60 to 95.
0.5% to 10% by weight of polyoxyethylene polyoxypropylene polyol having 3 to 20% by mole of terminal oxyethylene, which has been subjected to random addition polymerization by mol%, is contained in the polyol component in an amount of (D) polymer polyol, (E) A method for producing a polyurethane foam is characterized in that water is used as a crosslinking agent and a foaming agent, and a catalyst, a foam stabilizer and, if necessary, an additive are used.

The polyisocyanate (A) used in the present invention is a mixture of tolylene diisocyanate (TDI) and diphenylmethane type polyisocyanate. As TDI, 2,4-TDI, 2,6-TDI
The isomers may be used alone or in a mixture at any ratio, or crude TDI and the like. Examples of the diphenylmethane-based polyisocyanate include diphenylmethane diisocyanate (MDI), 2,2′-MDI, 2,4′-MDI,
4,4'-MDI, polymethylene polyphenyl polyisocyanate (polymeric MDI) and the like can be mentioned, and these can be used alone or as a mixture in an arbitrary ratio. Further, as the (A) polyisocyanate, a urethane-modified polyisocyanate partially reacted with a polyol, and further these isocyanates are biuret, allophanate, carbodiimide, oxalidone,
Also included are polyisocyanates modified with amides, imides, uretoimines, isocyanurates and the like. Preferred polyisocyanates include 2,4-TDI and 2,6
80:20 parts by weight of TDI mixture and Polymeric M
It is a mixture with DI.

The long-chain polyol (B) used in the present invention is a polyoxyethylene polyoxypropylene polyol having a molecular weight of 3500 to 10000 and oxyethylene of 5 to 35 mol% added to the terminal having 2 or more functional groups. These polyols are, for example, ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl-1,5. -Pentanediol,
Glycerin, trimethylolpropane, pentaerythritol, sorbitol, sugar alcohols such as sucrose, glucose, bisphenol A, ethylenediamine, propylenediamine, diethylenetriamine, toluenediamine, metaphenylenediamine,
Using one or more compounds having two or more active hydrogens such as diphenylmethanediamine and xylylenediamine as an initiator, ethylene oxide (EO), prepylene oxide (PO), butylene oxide, amylene oxide, glycidyl ether. , Methyl glycidyl ether, t-butyl glycidyl ether, phenyl glycidyl ether, and the like, which are produced by addition-polymerizing one or more monomers by a known method. Preferably, it is obtained by addition polymerization of EO, PO, etc., and has a molecular weight of 4000 to 6000, a functional group number of 2 to 4, more preferably 2.5 to 3.5, and an EO terminal content of 5 to 30 mol%. , And more preferably 10 to 25 mol%.

The defoaming agent (C) used in the present invention has an average number of functional groups of 2 to 6 and a hydroxyl equivalent of 800 to 5
000, the molecular weight is 4500 to 10,000, and oxyethylene is random addition polymerized at 60 to 95 mol%. For example, 60 to 95 mol% of oxyethylene, preferably 65 to 90 mol% of random addition polymerization is carried out using as an initiator a single compound or an arbitrary mixture of compounds having two or more active hydrogen groups used for obtaining a long-chain polyol. It was made. Such a polyol contains 3 to 20 mol% of terminal oxyethylene, preferably 5 to 15 mol%. Preferably, the number of functional groups is 2.5 to 4.0.
0.5 to 15% by weight of this foam breaking agent in the polyol component,
Preferably, by using 0.5 to 10% by weight, the cells of the polyurethane foam are made into continuous cells to facilitate crushing, and at the same time, impact resilience and compression set are improved.

Examples of the polymer polyol (D) used in the present invention include those obtained by reacting the long chain polyol (B) with acrylonitrile in an amount of 5 to 40% by weight, and the acrylonitrile and styrene (30 to 80 /
70 to 20 weight mixture).
By adjusting the amount of such polyol used,
Polyurethane foam can improve appropriate hardness and mechanical properties. A preferred polymer polyol has an average number of functional groups of 3, a molecular weight of 5000, and an EO terminal content of 17
% Polyoxyethylene polyoxypropylene polyol to 20% acrylonitrile solid content.

Examples of the (E) crosslinking agent used in the present invention include ethylene glycol, propanediol, butanediol, pentanediol, hexanediol,
Diethylene glycol, dipropylene glycol, 2,
2-bis (4-hydroxyphenyl) propane, 1,4
-Low molecular weight diols such as cyclohexanedimethanol, low molecular weight trifunctional or higher functional polyols such as glycerin, trimethylolpropane and pentaerythritol, hydroxyl groups obtained by addition polymerization of alkylene oxides using an active hydrogen compound as an initiator Terminated polyethers and hydroxyl terminated polyesters can be used.

Water is used as the foaming agent used in the present invention. Others, for example n- and iso-pentane, especially industrial mixtures thereof, liquid hydrocarbons such as n- and iso-butane, propane, ethers such as furan, dimethyl ether and diethyl ether, ketones such as acetone and methyl ethyl ketone. It is also possible to use carboxylic acid alkyl esters such as compounds, methyl formate, dimethyl oxalate, ethyl acetate, etc.

The catalyst used in the present invention is a known catalyst and is not particularly limited. For example, as the amine catalyst, triethylamine, tripropylamine, tributylamine, hexadecyldimethylamine, N-methylmorpholine, N -Ethylmorpholine, N-octadecylmorpholine, diethylenetriamine, N, N, N ', N'
-Tetramethylethylenediamine, N, N, N ', N'
-Tetramethylpropylenediamine, N, N, N ',
N'-tetramethylbutanediamine, N, N, N ',
N'-tetramethyl-1,3-butanamine, N, N,
N ', N'-tetramethylhexamethylenediamine, bis [2- (NN-dimethylamino) ethyl] ether, N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N, N' , N ′, N ″,
N ″ -pentamethyldiethylenetriamine, triethylenediamine, salts of triethylenediamine, oxyalkylene adducts of amino groups of primary and secondary amines, N, N
An azacyclo compound, such as a dialkylpiperazine,
There are various N, N ′, N ″ -trialkylaminoalkylhexahydrotriamines and the like, and as the organometallic urethane-forming catalyst, tin acetate, tin octetanoate, tin oleate, tin laurate, dibutyltin dichloride, There are lead naphthenate, nickel naphthenate, cobalt naphthenate, etc. These catalysts may be used alone or in a mixture, and the amount of the catalyst used may be 0.
001 to 10 are suitable.

The foam stabilizer used in the present invention is preferably an organosilicon surfactant, for example, L-520, L-532, L-540, L-544 and L manufactured by Nippon Unicar.
-550, L-3500, L-3600, L-3600
1, L-5305, L-5307, L-5309, L-
5710, L-5720, L-5740M, L-620
2. SH-190, SH-19 made by Toray Silicone
2, SH-194, SH-200, SRX-253, S
RX-274C, SF-2961, SF-2962, S
RX-280A, SRX-294A, Shin-Etsu Silicone's F-114, F-121, F-122, F-22
0, F-230, F-258, F-260B, F-31
7, F-341, F-601, F-606, X-20-
200, X-20-201, Toshiba Silicone, TF
A-4200, TFA-4202, Gold Schmidt B-4113 and the like. The amount of the foam stabilizer used is 0.1 to 3.0% by weight based on the total amount of the compound having active hydrogen and the polyisocyanate.

Additives used as necessary in the present invention include flame retardants, pigments, stabilizers, antifungal agents, etc.
Flame retardants such as trischloroethyl phosphate, trisdichloropropyl phosphate and chlorinated paraffin, pigments such as carbon black and titanium oxide, stabilizers such as di-t-butylphenol and α-methylstyrene can be used.

In the production of the flexible polyurethane foam of the present invention, for example, the mold is kept warm at 40 to 80 ° C., the polyisocyanate solution and the polyol solution are mixed and injected, and then post-cured at the same temperature. It can be manufactured.

The flexible polyurethane foam obtained by the present invention can be used for, for example, furniture cushions, automobile seat cushions, seat backs, saddles, headrests and the like.

[0017]

EFFECTS OF THE INVENTION According to the production of the flexible polyurethane foam of the present invention, the use of a specific defoaming agent causes cracking of a molded product during crushing, shrinkage of the molded product due to insufficient crushing, and deterioration of cushioning performance. You can escape.

[0018]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto. In Examples and Comparative Examples, parts and% represent parts by weight and% by weight, respectively, unless otherwise specified.

Examples 1 and 2 and Comparative Example 1 After the flexible polyurethane foam was foamed in the mold at the compounding ratio (parts) shown in Table 1, it was taken out of the mold and immediately subjected to roller crushing to crack the molded product. The presence or absence of was observed. In addition, after leaving the molded product after crushing for a whole day and night, J
The foam physical properties were measured according to IS K 6401.

(Foaming conditions) Mold shape: 400 × 400 × 50 mm Material: Aluminum Mold temperature: 55 ± 2 ° C. Mixing method: High pressure machine mixing Raw material temperature: 25 ± 2 ° C. Cure condition: 55 ± 2 ° C. × 5 minutes Crushing conditions: 5-stage roller, 90% compression

(Raw materials used) Polyol component Polyol A: Average number of functional groups: 3, hydroxyl value: 34 (mgK
OH / g), a polyoxyethylene polyoxypropylene polyol having an EO terminal content of 17 mol%. Polyol B: polymer polyol, average functional group number 3,
A reaction product of polyoxyethylene polyoxypropylene polyol having a molecular weight of 5000 and an EO terminal content of 17 mol% and acrylonitrile solid content of 20%. Polyol C: Average number of functional groups 3.3, hydroxyl value 28 (m
gKOH / g), EO terminal content 15 mol%, total EO
Random addition polyoxyethylene polyoxypropylene polyol having a content of 80 mol%. Isocyanate component TM-70: A mixture of 30 parts of Coronate T-80 (manufactured by Nippon Polyurethane Industry Co., Ltd., TDI) and 70 parts of Millionate MR200 (manufactured by Nippon Polyurethane Industry Co., Ltd., Polymeric MDI, NCO content 31.0%). Catalyst: Toyocat MR manufactured by Tosoh Foam stabilizer: SF-2962, manufactured by Toray Silicone

[0022]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location (C08G 18/66 101: 00) C08L 75:04

Claims (1)

[Claims] 1. Toluene diisocyanate and diphenylmethane polyisocyanate are used as (A) polyisocyanate, and (B) long-chain polyol has 2 or more functional groups, molecular weight of 3500 to 10000, and terminal oxyethylene of 5 to 3;
Polyoxyethylene polyoxypropylene polyol added with 0 mol% was used, and (C) as a defoaming agent, the average number of functional groups was 2 to 6, the hydroxyl equivalent was 800 to 5000, and oxyethylene was 60
.About.95 mol% random addition-polymerized polyoxyethylene polyoxypropylene polyol having 3 to 20 mol% of terminal oxyethylene in the polyol component
10% by weight of (D) polymer polyol, (E) cross-linking agent, water as a foaming agent, a catalyst, a foam stabilizer, and if necessary additives are used. .