JPS5893715A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain a low-odor, uniform, low-density polyurethane foam, by employing a catalyst represented by a specified alkydimethylamine, a specified compound having an active hydrogen and a polyisocyanate. CONSTITUTION:A polyurethane foam is obtained within a shortened molding time without forming burn marks even when a combination with a different catalyst is used, by reacting a compouns having at least two active hydrogens and a MW of 400-10,000, a polyisocyanate and water and/or a blowing agnet in the presence of a specified catalyst consisting of an alkyldimethylamine represented by the formula, wherein R is a 6-10C alkyl. In the above formula, the alkyl is preferred to be a straight alkyl but may be a branched alkyl or a mixture of the both. It is preferred to use a compound of the formula, as a catalyst, in combination with a tert. amine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyurethane foam, and more specifically, it has little odor, enables uniform low-density curing foaming, and does not cause discoloration even when used in combination with other catalysts. The present invention relates to a method for producing polyurethane foam using a specific catalyst that makes it possible to shorten the molding time.

Catalysts are widely used in the production of polyurethanes by reaction with polyisocyanates, polyols, and possibly other components; in this case, catalysts balance multiple simultaneous reactions during the production process. It is required to maintain and act competitively. One of the reactions that occur in the polyurethane manufacturing process is the reaction of polyisocyanates and polyols, which produces polyurethane, which results in chain extension and increased viscosity. Another reaction is the reaction of polyisocyanates with asane to form urea bonds and chain extension. Yet another reaction is the reaction of polyisocyanates with urethane or urea groups, which produces allophanate or biclet bonds and increases the crosslink density of the polymer.

Yet another reaction is the reaction of polyisocyanates with water, which generates foam with the evolution of carbon dioxide. This reaction of polyisocyanate 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 well-balanced; if the formation of the form is too fast compared to the chain elongation, the form will collapse; If chain elongation is too fast compared to form generation, form generation will be restricted. Control of these reactions depends on the selection of reaction conditions, but the selection of catalyst is most important.

Many catalysts have been known for use in producing polyurethane foam, and the catalysts are selected depending on the physical properties required to exhibit various physical properties. Due to its ease of molding, its uses have expanded to include automobile parts, furniture, eyelids, and more, and as a result, polycrethane is required to have harsh properties. In other words, ■ short molding time, ■ good fluidity during foaming, ■ low density of the resulting polyurethane foam, ■ good low-temperature dimensional stability, and ■ low brittleness. Performance requirements include (1) no discoloration or cracking of the polyurethane, and (2) low odor, but it has been 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 the foaming process will be lost, resulting in poor filling properties, and the resulting polyurethane foam will be prone to discoloration and cracks. It is difficult to simultaneously achieve these required performances using a catalyst. 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.

Therefore, the present inventors have made extensive research efforts to develop a catalyst that does not have such drawbacks and exhibits the above-mentioned performances at the same time.As a result, the present inventors have found that a specific 5th-class aquine exhibits satisfactory performance. They discovered something and completed the present invention.

That is, the present invention provides a method for producing polyurethane foam from a compound having at least two active hydrogen atoms and having a molecular weight of 400 to 1 O,000, a polyisocyanate, water and /l or a blowing agent, the following general formula: (In the formula, R is an alkyl group having 6 to 10 carbon atoms.) A method for producing polyurethane foam is provided, which is characterized by using a catalyst represented by the following formula.

The compounds of formula (1) according to the present invention can be produced in a number of ways using known synthetic techniques.

The compound of formula (1) according to the present invention is an alkyldimethylamine, and the alkyl group thereof has 6 to IO carbon atoms, and is preferably a linear one, but may be a branched one, or both A mixture of these may also be used. The reason why the number of carbon atoms is so narrowly limited is that if the number of carbon atoms in the alkyl group exceeds 10, the activity as a catalyst decreases, making it impossible to achieve the objective of shortening the molding time. Furthermore, if the number of carbon atoms in the alkyl group is less than 6, the odor will be significant. When the compound of formula [1] according to the present invention is used, the produced polyurethane foam has no amine odor, and it is possible to shorten the molding time. Furthermore, the polyurethane foam has excellent fluidity when made into a foam molded resin, and the resulting polyurethane foam has good dimensional stability, low brittleness, and no burning or cracking, making the polyurethane foam highly foamable (
It is slowed down by making it uniform (low density). In addition, when integrally molded, a polyurethane foam that exhibits good adhesion to adherends when molding sandwich panels, boxes, etc. can be obtained.

The symbol compound according to the present invention is triethylenediamine,
It can also be used in a catalyst in combination with a tertiary amine such as N, N, N', N'-tetramethylalkylene diamine or polyN-methylpolyalkylene polyamine. When used in combination, the ratio of the compound of formula (1) to these amines is from 100:1 to 1:100. In the production of high-density urethane, particularly hard high-density urethane, attempts to shorten the molding time by using triethylenediamine, tetramethylalkylenediamine, or polydomethylpolyalkylenebolyamine as a catalyst result in discoloration and cracking, but the present invention relates to the following. When the compound of formula (1) is used in combination,
Molding time can be shortened without causing burns or cracks.

Further, the compound of formula (1) according to the present invention can be used in combination with a tin-based catalyst. In order to shorten the molding time, if a tin-based catalyst is used to promote the resin-forming reaction, the curing speed will be increased, but the fluidity will be poor, making it difficult to fill the mold.

Therefore, tin-based catalysts such as triethylenediamine and N, H, N
',I,N'-Pentamethyldiethylenetriamine has also been used in combination, but this may result in poor filling properties.
It is highly brittle and has disadvantages such as peeling off from the adherend when demolding. However, when the compound of formula [1] according to the present invention is used in combination with a tin-based catalyst, the resin formation reaction is promoted and the brittleness is low.
It has good adhesion and will not peel off from the adherend. Known tin compounds that can be used in combination are: - or an alkylaryl group. ) 17 alkyl group, or aryl group, or alkylaryl group or -(H=COOR4 and R4 is carbon W
It~18 alkyl group) 1B alkyl group. ), etc. Among these, preferred are dibutyltin diacetate, dipyltin dilaurate,
Dibutyltin bis(monolacryl malate), dibutyltin dimebeak captoraclate. These tin compounds are 0.01 to 100% by weight of the compound of general formula (1),
Preferably, 0.1 to 10 weight groups are used.

When producing polyurethane foam from superpositioned wAK, it is of course necessary to use a substance that forms bubbles, but as is well known, such a substance reacts with polyisocyanate to release carbon dioxide. A blowing agent is used that does not take part in the generated water or the polyurethane production reaction. As the necessary blowing agent, any known blowing agent can be used, preferably a low-boiling halogenated hydrocarbon that is liquid at room temperature and vaporizes during the polyurethane production reaction. This water and foaming agent can be used independently, but it is preferable to use both together.

In addition, in the present invention, if necessary, the molecular weight is 52 to 40.
It goes without saying that the polyfunctional compound of No. 0 may be used together with a conventional chain extender, and the properties of the polyurethane foam obtained by using this chain extender may be adjusted as appropriate.

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, silicon-based ones are mainly used, and fluorine-based and ionic-based ones are used in combination as appropriate.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts in each example are based on weight.

Implementation-1 Hydroxyl number 450, N%, viscosity at 1.4° and 25°C 80 obtained by addition reaction of polypropylene oxide with a mixture of sucrose, ethylamine and water
00 cm, Boy's polyether polyol + 00 parts, water +, 5I! S, 1.5 parts of a silicone surfactant [Toray Silicone SH195 #Toray Silicone ■], each part of the catalyst shown in Table 1, and 40 parts of monofluorotrichloromethane [Freon 11B1 Mitsui Fluorochemical Co., Ltd.] were mixed. This mixture and crude 4.4j diisocyanate diphenylmethane [su2 Joule 44V-20, NOO content 5o
ys, Sumitomo Bayer Urethane ■] in a rotor stirring type urethane foaming machine (mixer rotation speed 4,000
r, f', s) under the same conditions and poured into the following mold.

l) 15 cm + x + 5 aax soaa (high Inside KO, 05m1 ~ Paste polyethylene film,
The inner polyethylene acid is degreased on two sides in the overlapping direction.
+zoI was injected from the above foaming machine into an open top wooden mold set with a 5-thick stainless steel plate.

The mold temperature, aluminum plate temperature, stock solution temperature in the foaming machine, and air temperature were all 25°C.

40 units (width) x 601 (
2809 was injected from the foaming machine into a sealable aluminum mold with a 0.05-polyethylene film attached to the inside of the mold (height) x 5.5 clL (thickness).

Mold temperature, stock solution temperature inside the foaming machine, and air temperature are all 25℃.
Met. Table 1 shows the results of measuring the catalyst of the present invention and the known catalyst in reaction systems with the same addition amount and gel time, and in the same molar concentration of N,N-dimethylalkylamine.

In addition, in the catalyst name abbreviations in the table, TRI)A is triethylenediamine, DMCA is N,N-dimethylcyclohexylamine, DMKA is N,N-dimethylethanolamine, DMBA)t N,N-dimethylbenzylamine, ClCd# ca#c11”141C+d
is the general formula 1 formula % Example 2 Using the same raw materials as in Example 1, the blending ratio was 100 parts of polyether polyol, 0.4 part of water, and 1 part of silicone surfactant.
．． 0 parts, monofluorotrichloromethane 24 parts, catalyst table 2
Mix the parts shown below.

This mixture and crude 4,4'-diisocyanate diphenylmethane were placed in a 201 poly bucket at a ratio of 14 KI to give an incyanate index of 1.06, using a Kikusui automixer (MIC-120 type 1.10 Or, p, approximately 121 after one blade, Kikusui Chemical). Stir for +5 seconds using an electric press (manufactured by Hanako Seisakusho), then inject the +5.5Kp into a wooden mold measuring 90cm x 90α x 50m (height) with a 0.05cm polyethylene film pasted on the inside. Area 1
60 minutes and 90 minutes after the mold was clamped (m x 2 m), it was circulated.

Dimensions of the molded product after demolding and the center of the molded product are 90 scratches x 45α
It was cut into 50x scratches and the internal condition was observed.

In addition, a 0.0511!1 polyethylene film was pasted on the inside of the same mold, and a degreased stainless steel plate with a thickness of 0.5 mm was set on the polyether, and the above mixed solution +01 lJ was injected into the upper part of the mold, and cream time was applied. ,
Gel time, tack free time, rise time, free foam density, surface brittleness after foam hardening, and adhesion to a stainless steel plate were measured. The mold temperature, raw material liquid temperature, and air temperature were all 20°C.

Table 2 shows the results of measurements of the catalyst system of the present invention and the known catalyst system in reaction systems with the same tack-free time.

In addition, in the catalyst name abbreviations in the table, TED& is triethylenediamine, TMHD is y, y, d, N″-tetramethylhexamethylenediamine, C8 is N,N-dimethyloctylamine, and 8n is dibutyltin dimercabutolamine. Indicates rate.

Claims (1)

[Claims] t has at least two active hydrogen atoms, and. In a method for producing polyurethane foam from a compound having a molecular weight of 400 to IO,000, a polyisocyanate, water and a heptad or blowing agent, the following general formula (in the formula, R is an alkyl group having 6 to 10 carbon atoms) is used. A method for producing polyurethane foam, characterized by using a catalyst represented by: