JPS62172011A - Polyurethane elastic foam - Google Patents

Abstract

PURPOSE:The titled foam useful as cushion for automobiles, having improved production speed and touch, obtained by reacting a mixture of a polyol, a crosslinking agent, a foam stabilizer, a blowing agent, a catalyst and an auxiliary with a specific aromatic polyisocyanate in a specific ratio. CONSTITUTION:A mixture of a polyol (e.g., adduct of trimethylolpropane with propylene oxide, etc.,), a crosslinking agent (e.g., ethylene glycol, etc.,), a foam stabilizer (e.g., organic silicon foam stabilizer, etc.,), a blowing agent (e.g., trichloromonofluoromethane, etc.,), a catalyst [e.g., bis(dimethylaminoethyl)ether, etc.,] and other auxiliaries is reacted with a blend of a diphenylmethane diisocyanate containing a methylene crosslinked polyphenylpolyisocyanate having >=3 nuclei and toluene diisocyanate and/or its isocyanate group end prepolymer in a weight ratio of 80/20-99/1 to give the aimed elastic foam.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to flexible or semi-rigid polyurethane elastic foams, and more particularly to polyurethane elastic foams using diphenylmethane diisocyanate.

(Prior Art) Soft or semi-rigid polyurethane elastic foams are widely used as interior materials for automobiles, such as furniture, vehicle cushions, crash pads, and headrests, taking advantage of their particularly high elasticity.

In recent years, there has been a movement to save energy, increase production speed, and improve tactility, and with this trend, diphenylmethane diisocyanate has attracted attention in place of toluene diisocyanate, which has conventionally been commonly used as a polyisocyanate for elastic foams.

As a result, a mixture of 80 to 70 grams of toluene diisocyanate and 20 to 30 grams of crude diphenylmethane diisocyanate is used as a polyisocyanate for so-called cold-cure soft, highly elastic foams.

(Problems to be Solved by the Invention) In order to further improve production speed and texture, it is necessary to use diphenylmethane diisocyanate (hereinafter abbreviated as MDI) as the main component of polyisocyanate. This causes various problems in terms of the foaming characteristics and physical properties of the polyurethane elastic foam.

Examples include 4.4'-MDI, 2.4'-MDI, 2.2
'-MDI.

Polyurethane elastic foams using only crude MDI containing trinuclear or more methylene-crosslinked polyphenyl polyisocyanates have poor tensile strength and elongation. Also 4, 4'
These physical properties can be improved by adding pure MDI consisting of -MDI, 2.4'-MDI and 2.2'-MDI or liquid MDI which is a modified product thereof to crude MDI. However, since the polyurea generated during foaming reduces the stability of the foam, the mixing ratio of pure MDI and crude MDI is 501.
If the weight ratio exceeds 50, the foam will collapse before it hardens. By adding 2.4'-MDI to pure MDI and increasing its content, the mixing ratio to crude MDI can be increased, but even in that case, the maximum is 80/20, and if the amount of pure MDI exceeds this, the foam As the curing of the foam is delayed, the compression set increases significantly, making the foam difficult to use.

(Means for Solving the Problem) As a result of various studies to solve this problem, the present inventors discovered that it is effective to add a small amount of trilene iononeanate or its prepolymer to the MDI mixture. We have arrived at the present invention.

That is, the present invention uses a methylene cross-linked polyurethane foam having three or more nuclei as the polyisocyanate when producing polyurethane foam by reacting a polyisocyanate with a mixture consisting of a polyol, a crosslinking agent, a foam stabilizer, a blowing agent, a catalyst, and other auxiliary agents. diphenylmethane diisocyanate including phenyl polyisocyanate toluene diisocyanate and/or
or 80 with its isocyanate group-terminated prepolymer
This is a method for producing polyurethane foam, characterized by using a mixture having a weight ratio of /20 to 99/1.

Diphenylmethane diisocyanate containing methylene-crosslinked polyphenyl polyisocyanate having three or more nuclear bodies used in the present invention is obtained by adding pure MDI or liquid MDI which is a modified product thereof to crude MDI, and further adding 2.4' as necessary.
- MDI is added and mixed. Crude MDI is 4.
4'-MD I 40-500-50% by weight'-MD
IO ~ 10% by weight, 2.2'-MDIO ~ 2% by weight,
It is a polyisocyanate consisting of 60 to 50% methylene crosslinked polyphenyl polyisocyanate having 6 or more nuclear bodies. In addition, pure MDI is 4.4'-MDI 80-100% by weight, 2.4'-MDI 0-20% by weight, 2.2'-
A composition consisting of ~1% by weight of MDIO, liquid MDI
is a polyisocyanate made by modifying pure MDI by trimerization, trimerization, carbodiimidation, etc., and making it liquid at room temperature.

Toluene diisocyanate (hereinafter abbreviated as TDI) is 2.4-TDI, 2.6-TDI and 80/2 of these.
0 or a 65/35 weight ratio mixture.

The isocyanate group-terminated prepolymer is a prepolymer obtained by reacting TDI with the following polyol, and the terminal isocyanate group content is suitably 5 to 45% by weight, particularly 20 to 350 to 35% by weight. %be.

The total amount of crude MDI, pure MDI, and 2.4'-MDI, that is, the mixing ratio of diphenylmethane diisocyanate containing trinuclear or more methylene-crosslinked polyphenyl polyisocyanate and toluene diisocyanate and/or its isocyanate group-terminated prepolymer is 80/ 20-99/1
The weight ratio is appropriate, especially 90/10 to 9.
A weight ratio of 515 is preferred. If the ratio of toluene diisocyanate is less than 1, the stability of the foam will be insufficient during foaming, resulting in phenomena such as cracking and collapse. Moreover, when it exceeds 20, the production speed of the foam decreases and the tactile sensation is not much different from that of normal soft foam. It is quite surprising that polyurethane elastic foams using MDI can be prevented from collapsing upon foaming by the addition of such a small amount of TDI component.

Further, in the diphenylmethane diisocyanate containing the methylene-crosslinked polyphenyl polyisocyanate having 3 or more nuclei, the content of the methylene-crosslinked polyphenyl polyisocyanate having 3 or more nuclei is preferably 10 to 30% by weight. If the amount of the methylene-crosslinked polyphenyl polyisocyanate having six or more nuclei is less than this range, the compression set of the elastic foam will increase, and if it exceeds this range, the tear strength and elongation of the foam will be insufficient.

Therefore, various M in the polyisocyanate of the present invention
A preferable mixing ratio of the D and TDI components is as follows.

44'-MDI 30-700-70
Weight% 2MDI 0-14 Weight%2.2
' -MDI O~ 1wt% TDI
By using polyisocyanate with such a composition in an amount of 1 to 20% by weight, the curing speed of the elastic foam is improved and hardness development is promoted.
High-speed molding becomes possible. That is, in the conventional method for producing soft, highly elastic foam using the cold key method, which uses polyisocyanate containing TDI as the main component and mixed with crude MDI, demolding takes 6 to 8 minutes, but in the method of the present invention, demolding takes 2 to 8 minutes.
Since demolding can be done in ~3 minutes, production can be greatly increased using the same equipment.

Furthermore, the tactile feel of the elastic foam is further improved, improving the ride comfort of the car. Furthermore, in the present invention, since the amount of fleas used in TDI is smaller than that in MDI, TDID dissolves in MDI, and as a result, the amount of volatilization is drastically reduced during formation of TDI.
It can solve the problem of poisoning due to steam ζ. Also M
Since DI is the main component, an elastic foam with low density and high hardness can be produced.

The polyols used in the present invention are water, ethylene glycol, propylene gelyl, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylene glycol, 1,3- and 1,4-butanediol, and 1,5-pentanediol. , 1,2-hexylene glycol, 1,10-tecanediol, 1,2-cyclohexanediol, 2-butene-1,4-diol, 3
-Cyclohexane-1,1-dimetatool, 4-methyl-3-cyclohexane-1,1-dimetatool, 3-methylene-1,5-bentanediol, (2-hydroxyethoxy)-1-propanol-4-(2 -hydroxyethoxy)-1-butanol, 5-(2-hydroxypropoxy)-1-pentatool, 1-(2-hydroxypropoxy)-2-octatool, 3-allyloxy-1,
5-bentanediol, 2-allyloxymethyl-2-methyl-1,3-bentanediol [(4,4-pentyloxy)-methyl]-i, s-7'lopanediol, 3-(o-7'lopenyl phenoxy) -1,2-
Propanediol, 2,2'-diisopropylidenehis(p-phenyleneoxy)getanol, Chrycerin,
1,2.6-hexanetriol, 1,1.1-1-limethylolethane, 1,1゜1-trimethylolpropane, 3-(2-hydroxyethoxy)-1,2-propanediol, 3-( 2-hydroxypropyl) -1
, 2-propanediol, 2,4-dimethyl-2-(2
-Hydroxyethoxy)-methylpencundiol-1
,5,1,1゜1-tris[(2-hydroxy)methyl]ethane, 1,1.1-tris[(2-hydroxypropoxy)-methyl]propane, pentaerythritol,
sorbitol, sucrose, lactose, α-methylglucoside, α
-Hydroxyalkyl glucosides, novolac resins, phosphoric acid, benzene phosphoric acid, polyphosphoric acids (e.g. tripolyphosphoric acid and tetrapolyphosphoric acid) and other polyhydric hydroxy compounds, ethylenediamine, diethylenetriamine, triethylenetetramine, methylene orthochloroaniline, 4 .Polyamines such as 4'-diphenylmethanediamine, 2,4-tolylenediamine, and 2,6-tolylenediamine, alkanolamines such as triethanolamine and jetanolamine, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, These are polyether polyols obtained by adding one or more types of styrene oxide, etc., or polytetramethylene ether glycol. Also, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol,
At least two of trimethylene glycol, 1,5- and 1,4-butanediol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, etc. one or more compounds having a hydroxyl group, and malonic acid, maleic acid, succinic acid, adipic acid, tartaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, trimellitic acid, hemimellitic acid at least 2 of
Also used are polyester polyols obtained from one or more compounds having carboxyl groups, or ring-opened polymers of cyclic esters such as polycaprolactone.

In addition, Special Publication No. 39-24737, Special Publication No. 41-3473,
Special Publication No. 43-22108, Special Publication No. 44-8230, No. 47-47597, No. 47-47999, No. 48-34991. JP-A-51-50398, JP-A-Sho 5
1-70286. JP-A-52-11249, JP-A-53
-4 [192, JP-A-53-4092, JP-A-53-1
5700. JP-A-54-64264, JP-A-53-78
297, JP-A-54-133599, JP-A-55-5
A so-called polymer polyol composition obtained by graft polymerizing an ethylenically unsaturated compound in a polyether polyol and/or a polyester polyol described in Japanese Patent No. 988 or the like is used. Ethylenically unsaturated compounds suitable for preparing such compositions include acrylonitrile, styrene, and the like.

Furthermore, 1,2-polybutadiene polyol and 1,4-polybutadiene polyol are also used.

The preferred range of the hydroxyl number of the various polyols mentioned above is 20 to 150 +lI KOH/I,
These polyols may be used alone or in combination.

The crosslinking agent used in the present invention is a monomer such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylene glycol, 1,3- and 1,4-butanediol. Polyols, alkanolamines such as triethanolamine and jetanolamine, aliphatic polyamines such as ethylenediamine, diethylenetriamine and triethylenetetramine, methyleneol-nochloroaniline, 4,4'-diphenylmethanediamine, aniline, 2,4-tolylene diamine Hydroxyl value 2 obtained by adding ethylene oxide, propylene oxide, etc. to amines, aromatic polyamines such as 2,6-tolylene diamine, and their active hydrogen compounds () OmgKo
) 1/9 or more of the compound. - Other compounds having a hydroxyl value of 200 mgKOH/7 or higher obtained by adding ethylene oxide and/or propylene oxide to hydroquinone, resorcinol, aniline, etc. can also be used.

The equivalent ratio (NCO/H) between the NCO group in the polyisocyanate and the active hydrogen in the polyol and crosslinking agent is 70~
One portion of polyisocyanate, polyol, and crosslinking agent are used so that the total weight is 140.

Catalysts that can be used in the present invention are conventionally known catalysts and are not particularly limited. , hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N-oftatecylmorpholine, monoethanolamine, jetanolamine, triethanolamine, N-methyljetanolamine, N
, N-dimethylethanolamine, diethylenetriamine, N, N, N', N'-tetramethylethylenediamine, N, N, N', N'-tetramethylpropylenediamine, N.

N, N', N'-tetramethylbutanediamine,
N, N, N'.

N'-tetramethyl-1,'5-butanediamine, N,
N.

N/, N/-tetramethylhexamethylenediamine, bis[2-(N,N-dimethylamino)ethyl]ether, N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, N,N,N ', N? N“
- azacyclic compounds such as pentamethyldiethylenetriamine, triethylenediamine, formates and other salts of triethylenediamine, oxyalkylene adducts of amino groups of primary and secondary amines, N,N-dialkylpiperazines, various N , N', N"-Trialkylaminoalkylhexahydrotriazines, Japanese Patent Publication No. 1982-43
517 β-aminocarbonyl catalyst, Japanese Patent Publication No. 53-14
279 β-amino nitrile catalyst, etc.), organometallic urethanation catalysts (tin acetate, tin octylate, silver oleate, silver laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octoate, naphthenic acid) lead, nickel naphthenate, cobalt naphthenate, etc.). These catalysts are used alone or in combination, and the amount used is [1
, 1:] 001~+o, o part.

The blowing agent in the present invention is one or a mixture of two or more of water, trichloromonofluoromethane, dichlorodifluoromethane, methylene chloride, trichlorotrifluoroethane, difuromotetrafluoroethane, trichloroethane, pentane, n-hexane, etc. be.

The foam stabilizer in the present invention is a conventionally known organosilicon surfactant, such as L-520 manufactured by Nippon Unicar Co., Ltd.
L-532, L-540, L-544,, L-550,
L-3550, r, -! 3305, L-3600, L-
3601, L-5305, L-5307, L-5309
, L-5710, L-5720, L-5740M, L
-6202, etc., and 5H of Toray Silicone company regulations.
-190,5H-192,5H-194,5H-200
,5RX-251゜5RX-274C,5F-2961
, 5F-2962, sp, x-28OA, 5RX-29
4A etc., F-114, F manufactured by Shin-Etsu Silicone Co., Ltd.
-121, F-122, F-220, F-230, F-
258, F-260B, F-317, F-341, F-
601, F-606, X-20-200, X-20-2
01, etc., and TFA-42 manufactured by Toshiba Silicone Co., Ltd.
00, TFA-4202, and B-4113 manufactured by Cold Schmidt.

The amount of these foam stabilizers used is 0.1 parts by weight per 100 parts by weight of the compound having active hydrogen and the organic polyisocyanate.
~5 parts.

In the present invention, in addition to the above, stabilizers, fillers, colorants, etc. can be used as necessary.

To carry out the present invention, a resin component is prepared by mixing a polyol, a crosslinking agent, a foam stabilizer, a catalyst, a foaming agent, and other auxiliary agents in predetermined amounts. Meanwhile, crude MD I, pure MDI, 2.4′-MD
Predetermined amounts of I, TD and/or its prepolymer are mixed to form a polyisocyanate component. Using a urethane foaming machine, the mixing ratio of both components is NCO/H = 0.70 to 140.
30. in advance while mixing so that Pour into a mold heated to ~50°C. Immediately close the lid and leave it at room temperature for 2 to 3 minutes, then remove the molded polyurethane elastic foam from the mold.

(Functions and Effects) According to the present invention, the curing speed of soft or semi-rigid polyurethane elastic foams is improved, and the production volume can be greatly increased using the same equipment. In addition, the tactile feel of the foam is improved, making it possible to improve the ride comfort of a car, and it is also possible to create a low-density, strong foam. Furthermore, it becomes possible to solve the problem of TDI poisoning during foam manufacturing work.

(Example) Next, examples of the present invention will be described.

The following raw materials were used in the examples.

Polyol A...Hydroxyl value 34.5ml obtained by addition polymerizing propylene oxide to trimethylolpropane, and then addition polymerizing ethylene oxide!
KOH/g triol.

Polyol B: A triol with a hydroxyl value of 27.8 m and 9 KOH/g obtained by addition polymerizing propylene oxide and ethylene oxide to glycerin.

Polyol C: A polymer polyol with a hydroxyl value of 27.8 + ngKOH/9 obtained by radical polymerization of acrylonitrile and styrene in polyol A.

Isocyanate D...Terminal NC○ made by reacting a triol with a molecular weight of 700 obtained by addition polymerizing propylene oxide to glycerin and toluene diisocyanate.
A prepolymer with a base weight of 30.5%.

B-4113: Organosilicon foam stabilizer manufactured by Cold Schmidt.

r, -5309...Organosilicon foam stabilizer manufactured by Nippon Unicar Co., Ltd.

L-1020... % diethylene glycol solution of triethylenediamine catalyst.

A-1...Bis(dimethylaminoethyl) dimonthyl catalyst.

F-11... Trichloromonofluoromethane blowing agent.

In the following examples, parts indicate parts by weight. The physical properties of the obtained polyurethane elastic foam were measured according to JISK-6501 and JISK-6401.

Example 1 200 parts of polyol A, 2 parts of jetanolamine, 62 parts of water, 20 parts of B-4113 foam stabilizer, 1.2 parts of L-1020 catalyst, 3 parts of A-1 catalyst, F-11 blowing agent 10.
0 parts were sufficiently mixed to form a resin liquid, and the temperature was adjusted to 25°C.

6 pure MD, crude MD I and 80/20 TDI
They were mixed at a weight ratio of 5:30:5 to form a polyisocyanate. The NCO group-containing base of this polyisocyanate is 33,6
%.

After stirring and mixing 84.4 parts of this polyisocyanate with the total amount of the resin solution (N CO / H = 0.9) for 6 seconds, a 400×40
Poured into 0x100ml aluminum molds. Immediately after injection, the lid was tightened and the mold was allowed to stand at room temperature. As a result, the mold could be removed within 5 minutes, and a perfectly shaped mold form could be created. This foam exhibited good physical properties as shown in Table 1, and had an extremely excellent feel to the touch.

Example 2 A polyurethane elastic foam was obtained in the same manner as in Example 1 except that polyol B was used instead of polyol A in Example 1. This foam exhibited good physical properties as shown in Table 1, and had an extremely excellent feel to the touch.

Example 3 A polyurethane elastic foam was obtained in the same manner as in Example 1 except that 40 parts of polyol A and 160 parts of polyol C were used instead of 200 parts of polyol A in Example 1. This foam exhibited good physical properties as shown in Table 1, and had an extremely excellent feel to the touch.

Table 1 Examples 4 to 8 Pure MD I, crude MDI, 80/20'rDI, and isocyanate D were mixed at the weight ratios shown in Table 2 to form polyisocyanates. These polyisocyanates were mixed with a resin solution having the composition shown in Table 2 and treated in the same manner as in Example 1. All of the resulting polyurethane elastic foams could be demolded in a short time, exhibited good physical properties as shown in Table 2, and had an extremely excellent feel to the touch.

Comparative Example 1 In Example 14, MDI was used as the polyisocyanate.
The process was carried out in exactly the same manner as in Example 1, except that 867 g of a mixture of 65:35 weight ratio of M.D. and crude g.MDr was used. After pouring into the mold, the foam collapsed during foaming.

Comparative Example 2 Pure MD I as the polyisocyanate in Example 1
, crude MDI and 80/20TD 45-Otsu 0:25
The process was carried out in exactly the same manner as in Example 1, except that a mixture of different weight ratios was used. When the mold was removed after being left for 3 minutes after injection, a portion of the foam was insufficiently hardened and became soft, causing deformation upon removal from the mold. There was also a toluene diisocyanate odor during demolding.

Claims (1)

[Claims] (1) When producing polyurethane foam by reacting a polyisocyanate with a mixture consisting of a polyol, a crosslinking agent, a foam stabilizer, a blowing agent, a catalyst, and other auxiliaries, the polyisocyanate is methylene-crosslinked polyphenyl having 3 or more nuclei. 80/20 of diphenylmethane diisocyanate containing polyisocyanate and toluene diisocyanate and/or its isocyanate group-terminated prepolymer
A polyurethane elastic foam characterized by using a mixture having a weight ratio of ~99/1.