JP2001278942A - Polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a urethane foam excellent in preventing yellowish discoloration affected by ultraviolet ray and NOX, and having a uniform cell structure. SOLUTION: The polyurethane foam manufactured by reacting a polyol compound with a polyisocyanate compound by specifying the polyisocyanate compound to a aliphatic and/or alicylic polyisocyanate compound modified by the mixture 50-80 wt.% of polyol and/or polythiol having tree active hydrogen atoms at the terminals with average mol.wt. of <=1,000 (A) and 50-20 wt.% of polyol and/or polythiol having two active hydrogen atoms at the terminals with average mol.wt. of <=1,000 (B), and containing 15% or mire NCO, and is, also, characterized by use of a catalyst to trimerize a isocyanate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An object of the present invention is to provide a polyurethane foam having yellowing resistance to the action of ultraviolet rays and NOx, and having excellent cell uniformity.

[0002]

2. Description of the Related Art Polyurethane foam is used for materials such as cushioning materials due to its excellent performance such as light weight and elasticity.
It is widely used for industrial materials, clothing applications such as shoulder pads, and various other applications. In the production thereof, aromatic polyisocyanates such as toluene diisocyanate are usually used. However, polyurethane foams obtained using aromatic polyisocyanates tend to discolor (yellow) relatively easily by light such as sunlight. As means for preventing such yellowing, a polyurethane foam using an aliphatic polyisocyanate or an alicyclic polyisocyanate instead of the aromatic polyisocyanate has been proposed.

[0003] For example, Japanese Patent Publication No. 52-30437 discloses that an aliphatic or alicyclic polyisocyanate is protected from weathering and oxygen while maintaining the physical properties of a polyurethane foam by using a special catalyst. A technique for improving the quality is described in JP-B-54-1559.
No. 9 uses a polyisocyanate in which NCO is not directly bonded to an aromatic ring as an isocyanate,
It is disclosed that the use of a specific catalyst provides polyurethane color stability. JP-A-54-1
No. 62795 discloses that aliphatic and / or alicyclic polyisocyanates are selected from the group consisting of alkali metal hydroxides / alcoholates or phenolates / alkali metal salts of weak acids or hexahydrotriazine-S- derivatives. By using together at least one compound selected from the group consisting of organic compounds of tin, zinc or iron, the photostability is improved, that is, the yellowing by light is improved. Is described.

[0004] However, the above proposal still has some problems. That is, when an attempt is made to produce a polyurethane foam using an aliphatic or alicyclic polyisocyanate, it is difficult to adjust the balance of the reaction, that is, it is difficult to adjust the non-uniformity of the reaction depending on the site or the imbalance of polymerization and foaming. In some cases, cell turbulence may occur in some of the bubbles presumed to be caused by the above. Also, when a slab block is manufactured, large variations in density occur between the upper and lower portions of the block.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyurethane foam having a uniform cell structure, which has a yellowing resistance to ultraviolet rays and NOx, which are disadvantages of conventional polyurethane foams. I do.

[0006]

According to the present invention, there is provided a polyurethane foam obtained by reacting a polyol component and a polyisocyanate component, wherein the polyisocyanate component has (a) an average molecular weight of 1,000 or less and an activity of 3 or more at the terminal. Modified with a polyol and / or polythiol, comprising 50% by weight to 80% by weight of a compound having hydrogen and (b) 20% to 50% by weight of a compound having an average molecular weight of 1000 or less and having two active hydrogen terminals.
A polyurethane foam containing an aliphatic and / or alicyclic polyisocyanate having an NCO content of 15% or more. Specifically, the present invention relates to the above-mentioned modified polyisocyanate, wherein the above-mentioned polyol and / or
Or reacting an excess of an aliphatic and / or cycloaliphatic polyisocyanate in a mixture of the polythiols (a) and (b) in excess of the active hydrogen equivalents of (a) and (b) to obtain substantially all The present invention relates to a polyurethane foam characterized in that active hydrogen has been reacted with isocyanate groups. In particular, the present invention relates to the above polyurethane foam produced further comprising a catalyst for trimerizing isocyanate in addition to the polyisocyanate component and the polyol component.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyisocyanate component comprising: (a) a compound having an average molecular weight of 1,000 or less and having at least three active hydrogen atoms at the terminal; and (b) a compound having an average molecular weight of 1,000 or less and two at the terminal. It is characterized in that an aliphatic and / or alicyclic polyisocyanate modified with a polyol and / or a polythiol comprising a compound having active hydrogen is used.

As the aliphatic and alicyclic polyisocyanates used herein, any of those usually used for producing polyurethane foams can be used. Examples of the aliphatic polyisocyanate include diisocyanates such as hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, and octamethylene diisocyanate. Examples of polyisocyanates include isophorone diisocyanate (IPDI),
Hydrogenated diphenylmethane diisocyanate (hydrogenated MD
I), diisocyanates such as hydrogenated xylene diisocyanate (hydrogenated XDI) cyclohexane diisocyanate, methylcyclohexane diisocyanate, dicyclohexylmethane diisocyanate and the like.
Xylene diisocyanate (XD) having an aromatic ring but having an isocyanate group not directly bonded to the aromatic ring
I), tetramethyl xylene diisocyanate (TMX
DI) can also be used in the present invention as belonging to the aliphatic diisocyanate. Particularly preferred among these polyisocyanates are HDI and IPDI.

Examples of (a) polyols and polythiols having an average molecular weight of 1,000 or less and having three or more active hydrogen atoms at the terminal used for preparing the modified aliphatic and / or alicyclic polyisocyanate include: Methylolpropane, glycerin, diglycerin, pentaerythritol, sorbitol and the like can be mentioned. Also,
(B) Examples of polyols and / or polythiols having an average molecular weight of 1000 or less and having two active hydrogens at the terminals include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol,
Butylene glycol, neopentyl glycol and the like.

The ratio of the active hydrogen-containing compounds (a) and (b) used for preparing the modified polyisocyanate is (a) :( b) in a weight ratio of 50-80: 50-2.
0, preferably 50-60: 50-40.

An aliphatic polyisocyanate and / or an alicyclic polyisocyanate is used as an active hydrogen-containing compound (a).
In the modified polyisocyanate obtained by modification according to (b), it is desirable that substantially all of the active hydrogen reacts with the isocyanate group, and the hydroxyl group and the thiol group do not substantially remain. The NCO content in the modified polyisocyanate is preferably at least 15%.

The polyurethane foam of the present invention comprises the modified polyisocyanate as a polyisocyanate component,
It is produced by reacting this with a polyol component. As the polyisocyanate component, an unmodified aliphatic polyisocyanate and / or an alicyclic polyisocyanate can be used in combination with the above-mentioned modified polyisocyanate. In this case, the proportion of the unmodified polyisocyanate used in combination is 80% by weight or less, preferably 20% by weight or less, based on the total polyisocyanate. As the unmodified polyisocyanate that can be used, one or more of the above-mentioned polyisocyanates modified with a hydroxyl group and / or a thiol group can be selected.

The polyol which can be used as a polyol component in the present invention has two or more hydroxyl groups in one molecule, and any polyol which has been conventionally used for producing a polyurethane foam can be used. Such polyols include, for example, polyether polyols.
, Polyester polyols, polycarbonate polyols, and polybutadiene polyols. The polyether polyol is produced by addition polymerization of an alkylene oxide (eg, ethylene oxide, propylene oxide, etc.) using one or more compounds having at least two active hydrogen atoms in one molecule as an initiator. You. Examples of the compound having at least two active hydrogen atoms used herein include ethylene glycol, propylene glycol, glycerin, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, and sucrose.

As the polyester polyol, a polycarboxylic acid and a compound which is used as an initiator of the polyether polyol and has two or more hydroxyl groups in one molecule, for example, ethylene glycol, propylene glycol, trimethylolpropane, etc. Esters of polyarbonic acid, adipic acid, maleic acid,
Using at least one compound having at least two carboxyl groups in one molecule such as succinic acid and malonic acid,
It can be manufactured by a known method. These polyols can be used alone or in combination of two or more.

The polyurethane foam of the present invention is preferably produced by adding a trimerization catalyst for isocyanate in addition to the polyisocyanate component and the polyol component. By adding a trimerization catalyst,
In the produced polyurethane foam, the balance between the resinification reaction and the foaming reaction is further improved. Examples of the trimerization catalyst that can be used for this purpose include potassium octylate, potassium acetate, and the like. These trimerization catalysts are generally used in an amount of about 0.5 to the polyol component.
To 5.0% by weight, preferably 1.0 to 3.0% by weight.

In producing the polyurethane foam of the present invention, a foaming agent, a foam stabilizer, and a catalyst are generally used in addition to the above-mentioned polyisocyanate and polyol components constituting the skeleton of the polyurethane, and further, the above-mentioned trimerization catalyst. Mix. As the foaming agent, water that can generate a gas such as carbon dioxide gas by reacting with an isocyanate group is generally used, but other gas such as pentane itself is a gas under the manufacturing conditions and forms bubbles as it is. Low boiling organic solvents that can be used can also be used. Although any of the above can be used in the present invention, water is particularly preferred. In the case of water, the compounding amount is about 1.0 to 7.0% by weight based on the polyol component.

As the foam stabilizer, a silicone-based foam stabilizer known to those skilled in the art can be used. Commercially available foam stabilizers can be used, and specific examples thereof include “SH-190” and “SH-19” manufactured by Toray Silicone Co., Ltd.
2, SF2904, Nippon Unicar's L-5
309 "," L-5305 "," L-520 "," S-7 "
26-10 ". The amount of the foam stabilizer used is 0.1 to 5 parts by weight per 100 parts by weight of the polyol component.

The catalyst is not particularly limited, and all amine-based catalysts, metal catalysts, diazabicycloalkenes or salts thereof which are usually used in the production of polyurethane foam in the present invention can be used. As amine catalysts, triethylenediamine, diethanolamine, bis- (2-
Aminoethyl) ether, N-ethylmorpholine, triethylamine, tetramethylhexamethylenediamine and the like. Examples of the metal catalyst include stannas octate, dibutyltin diacetate, dibutyltin dilaurate, and the like. As the diazabicycloalkanes, 1,8-diazabicyclo (5,4,0) undecene-
7 (hereinafter abbreviated as DBU) 1,5-diazabicyclo (4,3,0) nonene-5,6-dibutylamino-1,8-
Examples include diazabicyclo (5,4,0) undecene-7. In addition, alkali metal salts of weak acids and the like can also be used.

In the present invention, a surfactant, an antioxidant, an ultraviolet absorber, a flame retardant, a coloring agent, an antibacterial agent, a fragrance, etc. may be used as necessary if necessary. Can be.

The production of the polyurethane foam of the present invention using these raw materials does not require any special technique, and a conventional polyurethane foam production method such as a slab foaming method can be applied as it is. .
That is, generally, the polyisocyanate component, the polyol component, the catalyst and water, and the other additives stored or prepared in separate containers are charged into one reaction container, and the reaction is performed while thoroughly stirring and mixing. Let it start. Since the urethanization reaction and foaming start with the generation of heat, the mixture is poured onto a conveyor lined with a mold and a base paper, and the reaction, foaming, and curing are performed. The NCO content used in the above description and in the following examples is
It means the weight percentage of the total NCO contained in the polyisocyanate molecule.

[0021]

The present invention will be described more specifically with reference to the following examples. Example 1 (1) Preparation of modified polyisocyanate In a reaction vessel, 31 g of ethylene glycol, 44.7
g of trimethylolpropane (TMP) and 804 g
Of isophorone diisocyanate (IPDI)
While blowing in a nitrogen seal, the mixture was stirred and reacted for about 2 hours. After the reaction, the mixture was cooled to obtain a modified polyisocyanate having an NCO content of 25%.

(2) Production of Polyurethane Foam 100 parts by weight of FA703 (manufactured by Sanyo Chemical Industries, Ltd .; polyether polyol) as a polyol component and 110 parts by weight of the modified polyisocyanate prepared above as a polyisocyanate component were charged into a reaction vessel. . In the polyol component, 3 parts by weight of water as a blowing agent, 1 part by weight of DBU as a catalyst, 0.2 part by weight of dibutyltin dilaurate, and 1.0 part by weight of potassium octylate trimerization catalyst were used.
5 parts by weight of 1st stearyl phosphate as a buffer was added to 0.1 part.
1. 1 part by weight of a foam stabilizer "L-5305" was added. An exotherm occurred with mixing and foamed to form a polyurethane foam. After cooling, the foam was cut out and the properties of the polyurethane foam were evaluated. The evaluation results are shown in Table 1.

Comparative Example 1 A polyurethane foam was produced in the same manner as in the Example except that IPDI was used instead of the modified polyisocyanate.

Comparative Example 2 A polyurethane foam was produced in the same manner as in the Example except that 100 parts by weight of IPDI was used instead of the modified polyisocyanate.

[0025]

[Table 1]

[0026]

EFFECT OF THE INVENTION The polyurethane foam of the present invention has excellent yellowing resistance to ultraviolet rays and NOx, and also has excellent reaction uniformity. Can be expected.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4J034 CA04 CA05 CB04 CB05 CB07 CC02 CC03 CC08 DA01 DB03 DB07 DF16 DF20 DG02 DG03 DG04 HA01 HA07 HA18 HC03 HC09 HC12 HC22 HC46 HC52 HC61 HC64 HC67 HC71 HC73 JA42 KC12 KD04 KD02 KD04 KE02 NA01 NA05 NA08 QA03 QA05 QC01

Claims (4)

[Claims] 1. A polyurethane foam obtained by reacting a polyol component and a polyisocyanate component, wherein the polyisocyanate component has (a) an average molecular weight of 10
Compound 5 having not more than 00 and three or more active hydrogens at the terminal
NCO content modified with a polyol and / or polythiol consisting of 0% by weight to 80% by weight and (b) 20 to 50% by weight of a compound having an average molecular weight of 1000 or less and having two active hydrogen atoms at a terminal. A polyurethane foam, comprising at least 15% of an aliphatic and / or alicyclic polyisocyanate. 2. A modified polyisocyanate as claimed in claim 1, wherein said polyol and / or polythiol is present in a mixture of (a) and (b) in an amount equivalent to an excess of said active hydrogen equivalent of (a) and (b). The polyurethane foam according to claim 1, wherein substantially all active hydrogens obtained by reacting an alicyclic polyisocyanate are reacted with isocyanate groups. 3. The polyisocyanate component of 20 to 100.
The polyurethane foam according to claim 1 or 2, wherein the weight% is the modified polyisocyanate according to claim 1 or 2. 4. The polyurethane foam according to claim 1, which is produced further comprising a trimerization catalyst for isocyanate in addition to the polyisocyanate component and the polyol component.