JPS60235823A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain an odorless polyurethane foam by making uniform and low- density foaming possible, by reacting a compound having at least two active hydrogen atoms with a polyisocyanate and water or a blowing agent in the presence of specified catalyst compounds. CONSTITUTION:A polyurethane foam is produced by reacting a compound having at least two active hydrogens atoms and a MW of 400-10000 with a polyisocyanate and water and/or a blowing agent in the presence of a combination of a compound of formula I with a compound of formula II as a catalyst. Examples of the compounds of formula I include N,N,N',N'-tetramethylhexamethylenediamine. Examples of the compounds of formula II include 1-methyl-4'-(dimethylaminoethyl)piperazine. The amount of the catalyst used is preferably such that a combination of 0.1-5.0pts.wt. compound of formula I with 0.1-5.0pts.wt. compound of formula II is used per 100pts.wt. said compound having active hydrogen atoms.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing polyurethane foam, and more specifically, the present invention relates to a method for producing polyurethane foam, which has excellent fluidity, enables uniform low-density curing foam, and is cured in a short time. The present invention relates to a process for producing polyurethane foam that is complete, has excellent adhesive properties, and is substantially odorless.

[Conventional technology and problems]

Catalysts are widely used in the production of polyurethanes by reaction with polyisocyanates, polyols, and in some cases other components; catalysts are used to balance multiple simultaneous reactions during the production process. It is thought that they act competitively. One of the reactions that occur in the polyurethane manufacturing process is the reaction of polyincyanate and polyol, which forms polyurethane and results in chain extension and increased viscosity. Another reaction is the reaction of polyisocyanates with amines to form urea bonds.

Chain extension takes place. Still another reaction is the reaction of polyisocyanates with urethane groups or urea groups, which produces allophanate bonds or biuret bonds and increases the crosslink density of the polymer.

Yet another reaction is the reaction of polyisocyanates with water, which generates foam due to the evolution of carbon dioxide. This reaction of polyincyanate with water is not necessarily essential when other blowing agents are used. In order to obtain an excellent form structure through these reactions, each reaction must be balanced; if the formation of the form is too fast compared to the chain elongation, the form will collapse, and conversely, the chain will If the elongation is too fast compared to the generation of the foam, the generation of the foam will be restricted. Control of these reactions depends on the selection of reaction conditions, but
The choice of catalyst is most important.

Many catalysts have been known for use in producing polyurethane foam, and are selected depending on the physical properties required to achieve various physical properties.

Because polyurethane foam is easy to mold, its uses have expanded to include automobile parts, furniture, and footwear, and polyurethane is now expected to have harsh properties. In other words, ■The molding time is short, and ■The molding time is short. M i
, good fluidity during H fat formation, ■ low density of the resulting polyurethane foam, ■ absence of voids, ■ low brittleness, and ■ ability to adhere to adherend when integrally molded. The polyurethane is easy to use, (1) the resulting polyurethane does not burn or crack, (2) the odor is small, and the performance meets the required edges, but it was impossible to satisfy all of these requirements. For example, if a large amount of catalyst is added to shorten the molding time, the fluidity during foaming resin will be lost, resulting in poor filling properties, and the resulting polyurethane foam will be prone to discoloration and cracks. It is not possible to achieve these required performances at the same time. Furthermore, quinta-class amines, which are conventionally widely used catalysts, are indispensable in the production of polyurethane foams using water as a blowing agent. It has significantly reduced its value.

[Means for solving problems]

Therefore, as a result of intensive research to develop a catalyst that does not have such drawbacks and can simultaneously exhibit the above-mentioned properties, the present inventors have found that using a combination of two specific tertiary amines is more satisfactory than K. The present inventors have discovered that the present invention can exhibit excellent performance, and have completed the present invention.

That is, the present invention has at least two active hydrogens, and
With a compound having a molecular weight of 400 to 10,000.

A method for producing polyurethane foam from polyisocyanate, water and/or a blowing agent in the presence of a catalyst, characterized in that a compound represented by the following formula and a compound represented by the following formula are used in combination as a catalyst. The present invention provides a method for producing polyurethane foam.

That is, the multiple reactions that proceed simultaneously in the polyurethane production process described above are generally divided into two: (a) chain extension reaction and crosslinking reaction called resinization reaction, and (b) foaming reaction. The former (a) reaction is given priority, whereas the latter (b) reaction is given priority to the compound (I[]).

Typical catalysts for foaming reactions are N, N, N', N", N"
-pentamethyldiethylenetriamine, N, N, N',
N'-tetramethyl-2,2'diaminodiethyl ether, but these give too much priority to the foaming reaction, which delays the late reaction (curing reaction after foaming stops in urethane foam curing) and prevents complete curing. It takes a long time. In addition, if the amount added is increased, foaming in the initial reaction (up to 50% of the final volume in urethane foam curing) will give too much priority to foaming, and foams with low viscosity will be used for injection into complex shapes with small gaps and many obstacles. During molding, bubbles break and voids are generated, which causes a decrease in strength and insulation properties.

However, in the case of compound [II], foaming does not give much priority in the initial reaction, and like compound CI), the resin formation reaction takes priority, and the reaction in the middle stage (reaction after 50% foaming of the final foam volume in urethane foam curing) ), it was found that the foaming reaction takes precedence. However, with compound [■] alone, the late reaction is delayed and it takes a long time for complete curing, but by combining this compound Cl0) with compound [0], it is possible to form low-density urethane foam into complex shapes in a short time. Can be molded into

[Effect]

In the present invention, the proportion of the catalyst used is 0.1 to 5 parts by weight of a compound of formula CI) per 100 parts by weight of a compound that destroys at least two active hydrogen atoms and has a molecular weight of 400 to 10,000.
．． 0 parts by weight, preferably 0.5 to 3.0 parts by weight, and the formula [
π] compound 0.1 to 5.0 parts by weight, preferably 0.5
It is preferable to use a combination with 3.0 parts by weight.

The resin formation reaction rate and the foaming reaction rate can be variously adjusted by appropriately selecting the combination of catalysts according to the present invention.

Furthermore, the combination of the catalyst of the present invention is a compound of the formula [E] and [■]
It is also possible to use the compound in combination with a known urethanization catalyst.

The compound of formula CD, the compound of [II] according to the present invention can be produced by many methods using known synthetic techniques.

When producing polyurethane foam according to the present invention, it is of course necessary to use a substance that forms bubbles, and such substances include, as is well known,
Water, which reacts with the polyisocyanate to generate carbon dioxide, or a blowing agent, which does not participate in the polyurethane production reaction, is used. Any known blowing agent can be used, and preferably low-boiling halogenated hydrocarbons that are liquid at room temperature and vaporize during the polytalecne production reaction are used. Although the water and the blowing agent may be used alone, it is preferable to use both in combination.

In addition, in the present invention, if necessary, the molecular weight is 32 to 400.
Of course, the polyfunctional compound may be used as a normal chain extender, and the properties of the polyurethane foam obtained can be adjusted as appropriate by using this chain extender.

In the present invention, it is preferable to use a surfactant during the production of polyurethane foam to improve cell uniformity and cell retention.As such surfactants, silicone-based ones are mainly used, and fluorine-based ones, A general surfactant containing no silicone or fluorine is used in combination as appropriate.

[Examples and effects]

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts in the same example are based on weight.

Example Hydroxyl number 450 obtained by addition reaction of polypropylene oxide with a mixture of sucrose, ethanolamine and water. N% 1.7. Viscosity at 25°C 7000
100 parts of centiboise polyether polyol, 1 part of water
．． 5 parts, silicone surfactant [Toray Silicone 8H-
193,)-Resilicon Co., Ltd.:] 11.5 parts of catalyst Each part shown in Table 1 and 40 parts of monofluorotrichloromethane [Freon 11B1 Mitsui Fluorochemical Co., Ltd.] were mixed. This mixture and crude 4,4'-diincyanate diphene:=L)lp7[X Mishu-A/Is 4 V-20
, NCO content 30.7%, Sumitomo Bayer urethane (a
)] is the isocyanate index (incyanate equivalent/active hydrogen equivalent that can react with isocyanate) =
1. Rotor stirring type urethane foaming machine (
The mixture was mixed under the same conditions at a mixer rotation speed of 4,000 r, p, m) and poured into the following mold.

i) Cream time, gel time, free foam density, surface brittleness after foam curing 1 1501 to evaluate foam odor and adhesion to adherends! X 15cII
&X s ocn (height) inside 0.03iIi1
Attach polyethylene film.

0, which was degreased on two vertical sides to its inner polyethylene wall;
12Of was injected from the foaming machine into a wooden mold with an open top set with a stainless steel plate 5 mm thick. Mold temperature, aluminum plate temperature F'i50℃, stock solution temperature in the foaming machine,
The temperature was 20°C in both cases.

11) 15 @ (width) x 1 for measuring foam fluidity (fillability), foam density distribution, and presence or absence of voids
0.03 inside of 60η (length) x 3.5ae (thickness)
The mixture was injected from the foaming machine into one end of a wooden mold to which a polyethylene film was attached. At the other end, the temperature of the 50-pot open mold was 35°C, and the temperature of the stock solution inside the foaming machine.

The temperature was 20°C in both cases.

111) 30 width (width) x to measure swelling during demolding
0 inside so@(height) x s an (thickness),
It was poured from the foamer into a sealable aluminum mold covered with O5m polyethylene film. The mold temperature was 35°C, and the temperature of the stock solution in the foaming machine and the air temperature were both 20°C.

Evaluations of free foam core density, surface fragility, odor, adhesion, fluidity (fillability), foam density distribution, voids, and swelling during demolding are based on the following symbols.

Free foam core degree: 10 sides of foam center x 10
Cut into CnX10@, weight 11 constant t, Te x output (Kf
/rn') Surface fragility: ◎: Surface is not brittle immediately after curing 02 Surface is brittle only for 10 minutes ○: Slightly weak. ×: Strong.

XX=Very strong.

Adhesion: When the urethane foam and stainless steel plate were peeled off 10 minutes after injection foaming.

◎: Strong adhesion, complete form destruction.

○: Slightly strong adhesive strength, more than 80% of the adhesive surface Above is form destruction.

×: Weak adhesive force, 20 to 80 on the adhesive surface % is interfacial peeling.

XX: Adhesive strength is weak, and 80% or more of the adhesive surface peels off at the interface.

Fluidity (fillability): Length of the foam when injected at 300F (longer foam has better filling properties) Foam density distribution: When injected at 3oor, the density of the foam divided into 10 equal parts from the injection point to the tip of the foam Distribution (Ky/m').

(The smaller the density distribution, the better the molded product quality. stomach) Voids: Voids larger than φ5 throughout the foam. ◎: Not at all.

○: 1 to 5 pieces.

×: 6 to 10 cases.

XX: 11 or more.

Bulging during demolding: 250 When removed from the mold 5 minutes after injecting it, the thickness was 5G) Amount of bulging in the direction ( 朋 ) (With less blistering, the molding time can be shortened) Abbreviation of the catalyst used: A: Compound [x] N, N, N',)r'-tetramethylhexamethylenediamine B: Compound [■] 1-methyl-4'-(dimethylaminoethyl)piperazine c: IJ, N-dimethylcyclohexylamine D
Nitriethylenediamine v: N, N, N', N", N"-pentamethyldiethylenetriamine p; N, N, N', N'-tetramethyl-2,2'
- Diaminodiethyl ether The evaluation results of the properties of polyurethane foam depending on the type and combination of catalysts are summarized in Table 1.

Claims (1)

[Claims] 1. has at least two active hydrogens, and has a molecular weight of 4
00 to 10,000, a polyincyanate, water and/or a blowing agent in the presence of a catalyst, a compound represented by the following formula as a catalyst, and a compound represented by the formula A method for producing polyurethane foam, characterized in that it is used in combination with.