JP2631237B2 - Method for producing wet heat resistant flexible polyurethane foam - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a flexible polyurethane foam, and more particularly, to a flexible polyurethane foam having a wet heat resistance and excellent feeling by using a special copolyester polyol. Things.

[Conventional technology]

Conventionally, a so-called sebacic acid-based polyester polyol obtained by reacting sebacic acid with an aliphatic glycol has been known to have excellent water resistance. On the other hand, poly (hexamethylene adipate) -based polyester polyols derived from adipic acid and 1,6-hexanediol are not only useful as raw materials for polyurethane, but also ordinary poly (ethylene adipate) -based and poly (propylene adipate). System, poly (diethylene adipate)
It is also well known that polyurethanes derived from polyester polyols such as poly (butylene adipate) and the like have better hydrolysis resistance.

However, sebacic acid-based polyester polyols and poly (hexamethylene adipate) -based polyester polyols have high crystallinity, and their use alone in flexible polyurethane foams was not practical. That is, in many cases, it does not have a liquid property at room temperature, and even if it is a liquid, when it is made of a polyurethane foam, shrinking or sinking is not realistic. Adipate to which neopentyl glycol is partially added has also been proposed,
Even if a slight improvement in physical properties was made, there was no effect of lowering the crystallinity.

[Problems to be solved by the invention]

The present inventors have obtained the advantages of the sebacic acid-based polyester polyol and the poly (hexamethylene adipate) -based polyester polyol, obtained a polyester polyol for a flexible polyurethane free from the above-mentioned disadvantages, and then formed a wet-heat-resistant flexible polyurethane foam therefrom. As a result of intensive research and study for manufacturing, the present invention has been achieved.

[Means for solving the problem]

That is, in the present invention, when obtaining a flexible polyurethane foam from an organic diisocyanate, a polyester polyol, a blowing agent, a catalyst and a surfactant, the polyester polyol comprises a dicarboxylic acid mixture containing 50 mol% or more sebacic acid as an acid component. (A) trimethylolpropane, (b) diethylene glycol and (c) 1,6-
Number average molecular weight 1 obtained by reacting hexanediol and / or 3-methyl-1,5-pentanediol with (b) and (c) at a molar ratio of 40 to 80 mol%: 60 to 20 mol%
It is a moisture and heat resistant flexible polyurethane foam having a number average functional group number of from 000 to 4000 and a number average functional group of from 2.2 to 4.0.

The copolyester polyol which is a raw material for obtaining the moist heat-resistant flexible polyurethane foam of the present invention has low crystallinity, is liquid at ordinary temperature, is easy to handle, and is easily processed into a flexible polyurethane foam. The moisture and heat resistance of the obtained flexible polyurethane foam is based on the moisture resistance of the flexible polyurethane foam obtained from the reaction of trimethylolpropane and diethylene glycol with adipic acid, which is mainly used as the raw material of the flexible polyurethane foam. It is much better than heat.

(A) trimethylolpropane, (b) diethylene glycol and (c) 1,6-hexanediol and / or 3-methyl-1,5-pentanediol. The reaction of (a), (b), and (c) necessary for obtaining a predetermined number average molecular weight is added to the dicarboxylic acid, preferably at 150 to 250 ° C., preferably 180 ° C. in the presence of a catalyst. Method carried out at a temperature of ~ 230 ° C.

(A) in excess of the theoretical amount with respect to the dicarboxylic acid,
(B) and (c), preferably in the presence of a catalyst,
The reaction product is formed at a temperature of from 150 to 250 ° C, preferably from 180 to 230 ° C, and then from 150 to 250 ° C, preferably from 180 to 230 ° C.
A method in which trimethylolpropane and / or 3-methyl-1,5-pentanediol and / or 1,6-hexane glycol and / or diethylene glycol are distilled off under reduced pressure at a temperature of 0 ° C. until a predetermined molecular weight is reached. The above method is advantageous, and thus a copolyester polyol having a desired molecular weight can be produced.

And / or 1,6-hexane glycol and / or 3-methylpropane
The amount of methyl-1,5-pentanediol and / or diethylene glycol used is preferably 1.1 to 20 times the theoretical amount, preferably 5 to 15 times the theoretical amount, and the degree of decompression during the reduced pressure reaction was 200 times.
At a reaction temperature in ° C. of 3 to 5 mmHg is suitable.

In either case, it is desirable to carry out the reaction in the presence of a catalyst from the viewpoint of promptly proceeding the reaction. As such a catalyst, a general transesterification catalyst such as titanium, zinc, tin, lead, In addition to compounds of metals such as iron, organic sulfonic acids such as paratoluenesulfonic acid can be applied. Of these, titanium-tetra-alkoxides such as titanium-tetra-isopropoxide are preferable, and the amount of these catalysts used is 5 to 5.
Concentrations as low as 50 ppm are suitable.

The reaction is carried out at a reaction concentration of 150 to 250 ° C, preferably 180 to 230 ° C. At a low temperature such as 150 ° C. or lower, the reaction rate is remarkably reduced, and at a temperature higher than 250 ° C., a decomposition reaction of the copolyester polyol occurs, which is not preferable.

It is desirable to continuously remove the condensed water and / or monohydric alcohol generated by the reaction from the system through an inert gas stream such as nitrogen in order to promote the reaction and also to prevent coloration.

The time required to substantially complete such a reaction varies depending on the reaction conditions, but in this case, 5 to 25 hours, the reaction in the preceding stage of 3 to 20 hours, and the reaction under reduced pressure is 3 to 20 hours.
~ 15 hours.

In the production of the copolyester polyol, as the raw material dicarboxylic acid, other dicarboxylic acids such as adipic acid and azelaic acid can be used as long as the dicarboxylic acid mixture contains 50 mol% or more of sebacic acid.

Of the raw material polyols used in the present invention, trimethylolpropane is used for adjusting the number of functional groups. The number average functional group number of the copolyester polyol is 2.
2 to 4.0.

In this case, if it is less than 2.2, the wet heat resistance of the flexible polyurethane foam obtained from this copolyester polyol will be inferior, and if it exceeds 4.0, the copolyester polyol will have a high viscosity, and in the production of the flexible polyurethane foam, mixing will be difficult. The resulting foam tends to be inferior in physical properties.

3-Methyl-1,5-pentanediol or 1,6-hexane glycol improves wet heat resistance,
1,5-pentanediol is effective for room temperature liquefaction. Diethylene glycol contributes to liquefaction at room temperature and is effective in improving the feeling and physical properties of the obtained flexible polyurethane foam.

Further, the usage ratio of (b) diethylene glycol and (c) 1,6-hexanediol and / or 3-methyl-1,5-pentanediol is such that (b) :( c) is 40 to 80 mol%: 60 to 20 mol%.

In this case, the use ratio of (b) diethylene glycol is 40
When the amount is less than mol%, it tends to be difficult to maintain the resulting copolyester polyol at room temperature, and (c) 3-methyl-1,5-pentanediol and / or 1,6-hexanediol Is less than 20 mol%, the moisture and heat resistance of the obtained flexible polyurethane foam tends to decrease.

The flexible polyurethane foam having wet heat resistance of the present invention can be obtained by mixing the above-mentioned copolyester polyol, organic diisocyanate, foaming agent, catalyst and surfactant as required, and curing by heating.

In this case, the ratio R (NCO / OH) between the isocyanate equivalent and the active hydrogen equivalent in the organic diisocyanate is 0.9 to 1.2, preferably 0.95 to 1.05. When this ratio is 0.90 or less, the molecular weight does not increase so much, and the physical properties of the soft polyurethane,
Mechanical properties such as tensile strength, ultimate elongation, and tear resistance are inferior. When R is 1.2 or more, the degree of crosslinking of the flexible polyurethane is significantly increased structurally, and the ultimate elongation is generally significantly reduced.

As the organic diisocyanate used in the present invention,
Aliphatic diisocyanate such as hexamethylene diisocyanate, lysine diisocyanate, tolylene diisocyanate, phenylene diisocyanate, 4,4'-
Examples thereof include aromatic diisocyanates such as diphenylmethane diisocyanate, 3,3'-dimethyltrizine diisocyanate, and naphthylene diisocyanate, and aliphatic diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate, alone or in combination of two or more compounds thereof. Can be

A typical example of the reactive foaming agent used in the present invention is water. In addition, a foaming agent known in the art can be used as needed. These blowing agents can be used alone or in combination.

Examples of the catalyst include tertiary amines such as triethylamine, triethylenediamine, pentamethyldiethylenetriamine, dimethylethanolamine and ethylmorpholine, dibutyltin dilaurate, dioctyltin dilaurate, stannas octate, and octenoates of various metals. There are metal catalysts, and all of the above catalysts can be used as a mixture.

Surfactants that can be used in the present invention include:
All those effective for producing polyurethane foam can be used. Examples thereof include polyoxyalkylene-based ones such as polyoxyalkylene alkyl ether and polyoxyalkylene alkylamino ether, and dilicone-based ones such as organopolysiloxane and siloxaneoxyalkylene copolymer.

Additives that can be used as needed include
Antioxidants and antioxidants such as ultraviolet absorbers, fillers such as calcium carbonate and barium sulfate, flame retardants, plasticizers, coloring agents, antifungal agents and the like are known in the art.

The reaction conditions for soft polyurethane formation are as follows: the above-mentioned R is kept constant, the one-shot method in which predetermined raw materials are simultaneously charged, the total amount of copolyester polyol and diisocyanate and / or the copolyester polyol and diisocyanate are reacted at once, and then the remaining raw materials are mixed. A prepolymer method or a combination thereof is used, and the catalyst is preferably added from the beginning of the reaction.

These components are mixed and reacted using a known mixing device such as a low-pressure foaming machine, a high-pressure foaming machine, or a spray foaming agent.

For foaming, any of known methods such as a mold method, a slab method, and a spray method can be adopted.

The flexible polyurethane foam produced in this manner can be mainly used as a resin for foaming elasticity for general use such as clothing and footwear, and for industrial and industrial use.

〔The invention's effect〕

By using the polyester polyol of the present invention, the obtained flexible polyurethane foam has an excellent feeling and a favorable effect of wet heat resistance.

〔Example〕

The present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, the number of functional groups and the molecular weight of the polyester polyol are shown by a number average value.

Example 1 Production of Copolyester Polyol 1264 g (50 mol%) of adipic acid and 1748 g of sebacic acid were placed in a reaction vessel equipped with a partial condenser, a stirrer, a heating / cooling jacket, a nitrogen gas introducing pipe, and a pressure reducing line.
(50 mol%) of a mixed dicarboxylic acid was charged in a total of 3012 g. Next, 1334 g (75 mol%) of diethylene glycol
After charging a total of 2110 g of a mixed glycol of 496 g (25 mol%) of 1,6-hexanediol and 280 g of trimethylolpropane, 45 mg of tetra-n-butyltitanium is charged as an esterification catalyst, and the mixture is heated to 130 ° C. with stirring. The water generated by the dehydration reaction is distilled off slowly through nitrogen through a partial condenser. The temperature is raised to 210 ° C. while taking care not to distill the polyol component out of the reaction system. Thereafter, the temperature is maintained at 210 ° C. until no more water distills.
Next, the pressure is reduced to 20 mmHg while maintaining the temperature at 210 ° C., it is confirmed by sampling that the acid value has become 1.0 or less, and the reaction content is cooled to room temperature. Thus, a viscous copolyester polyol 1 was obtained. Copolyester polyol 1 has a hydroxyl value (OHV) of 60, an acid value (AV) of 0.4 and a functional group of 2.
7 had a molecular weight of 2500.

● Manufacture of flexible polyurethane foam <Formulation> Copolyester polyol 1 100 parts by weight Water 4.0 parts by weight Silicone L532 (Nihon Unicar Co., Ltd.) 1.5 parts by weight Kaolyzer No.21 (Kao Corporation) 1.0 parts by weight Stanas Octoate 0.01 parts by weight Coronate T-80 (Tolylene diisocyanate manufactured by Nippon Polyurethane) R = 1.05 Keep the temperature of each liquid used in the above formulation at 20 ° C., put each liquid in one polyethylene cup, and stirrer (TK homogenizer). (Disperser SL specialty machine company) at 4000 rpm, and quickly transferred to a 250 x 250 x 250 mm open top box for free foaming. The mold temperature is 20 ° C.

The heat resistance evaluation of the obtained flexible polyurethane foam was JI
The test was performed by measuring the tensile strength after 6 hours, 9 hours, 12 hours, and 24 hours by the method of wet heat aging test (reference) of SK-6401-1980, and comparing with the tensile strength of the foam before the test. .

Separately, regarding compression set, JISK-6401-1980
Was measured by a compression set test method, and compared with a comparative example.

Table 1 shows the measurement results of the physical properties of the flexible polyurethane foam.

Comparative Example 1 Adipic acid (2328 g), 1,6-hexanediol (2368 g) and tetra-n-butyltitanium (40 mg) were charged as an esterification catalyst, and a reaction was carried out in the same manner as in the production of the copolyester polyol of Example 1 to obtain a number average molecular weight of 1,000. Average number of functional groups 2.
0 polyester polyol was obtained. This polyester polyol was solid at room temperature, and a flexible polyurethane foam could not be produced.

Comparative Example 2 Same as Example 1 except that copolyester polyol (number average molecular weight: 2520, average number of functional groups: 2.65) mainly made of adipic acid, trimethylolpropane and diethylene glycol, which is mainly used for the production of flexible polyurethane foam, was used as a raw material. A flexible polyurethane foam was produced by free foaming. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Example 2 1270 g (50 mol%) of adipic acid and 1756 g (50 mol%) of sebacic acid
Mol%) of mixed dicarboxylic acid (3026 g) and diethylene glycol (1347 g (75 mol%)) and 3-methyl-1,5-pentanediol (500 g (25 mol%)) mixed diglycol and trimethylolpropane (2100 g). Number average molecular weight 2970, average number of functional groups 3.2, O
Copolyester polyol 2 of HV60.5 and AV0.4 was synthesized.

Using this copolyester polyol 2 as a raw material, a flexible polyurethane foam was produced in the same manner as in Example 1. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Example 3 3155 g of sebacic acid and 1206 g of diethylene glycol (75
Mol%) and 448 g (25 mol%) of 1.6-hexanediol in the same manner as in Example 1 except that the total charged amount of glycol and trimethylolpropane was 1907 g, and the average number of functional groups was 3.3 with a number average molecular weight of 3120 and OHV59. .4, a viscous copolyester polyol 3 was synthesized at room temperature of AV 0.4.

Using this copolyester polyol 3 as a raw material, a flexible polyurethane foam was produced in the same manner as in Example 1. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Example 4 3156 g of sebacic acid and 1205 g of diethylene glycol (75
Mol%) and 447 g of 3-methyl-1,5-pentanediol (2
(5 mol%), the total charge of the mixed diol and trimethylolpropane was 1905 g, and the number-average molecular weight was 3120, the average number of functional groups was 3.3, OHV was 59.4, and AV0.
No. 4 viscous copolyester polyol 4 at room temperature was synthesized.

Using this copolyester polyol 4 as a raw material, a flexible polyurethane foam was produced in the same manner as in Example 1. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Example 5 3127 g of sebacic acid and 794 g of diethylene glycol (5
0 mol%) and 884 g of 3-methyl-1,5-pentanediol
(50 mol%) A mixed liquid of triglycol propane and trimethylolpropane was used in the same manner as in Example 1 except that the total charged amount was 1930 g.
2. Copolyester polyol 5 of OHV 60.6 and AV 0.3 was produced.

Using this copolyester polyol 5 as a raw material, a flexible polyurethane foam was produced in the same manner as in Example 1. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Example 6 1564 g (50 mol%) of sebacic acid and 1456 g of azelaic acid
3050 g of a mixture (50 mol%) of diethylene glycol 796
g (50 mol%) and 3-methyl-1,5-pentanediol 88
6 g (50 mol%) of a mixed glycol and trimethylolpropane were mixed in the same manner as in Example 1 except that 1935 g was used.
A copolyester polyol 6 of 3.2, OHV 60.3 and AV 0.5 was produced.

Using this copolyester polyol 6 as a raw material, a flexible polyurethane foam was produced in the same manner as in Example 1. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Example 7 1758 g (50 mol%) of sebacic acid and 1271 g (50 mol%) of adipic acid
Mol%) mixture of 2929 g of diethylene glycol 1317 g
(75 mol%) and 3-methyl-1.5-pentanediol 489
g (25 mol%) in the same manner as in Example 1 except that the total amount of the mixed glycol and trimethylolpropane was 2071 g, and was a viscous liquid at ordinary temperature, with a number average molecular weight of 3540 and an average number of functional groups of 3.
8, Copolyester polyol 7 of OHV 60.2 and AV 0.4 was produced.

Using this copolyester polyol 7 as a raw material, a flexible polyurethane foam was produced in the same manner as in Example 1. The physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

Notes in Table 1 Measurement atmosphere: 20 ° C, 50% RH 1) 25% ILD: According to the hardness test method of JISK6401-1980.
The test piece is 250 × 250 × 50 mm.

2) 50% compression set: According to the compression set test method of JISK6401-1980. The test piece is 55 × 55 × 50 mm.

3) 80% compression set: According to the compression set test method of JISK6401-1980. The test piece is 55 × 55 × 50 mm.

4) T _B (tensile strength): The test piece was tested under the conditions of 20 × 120 × 10 mm and a pulling speed of 300 ^mn / min. Measuring equipment is AUTO GRA
PH IS-5000 (manufactured by Shimadzu Corporation).

Wet heat test: According to the JISK6401-1980 “reference” wet heat aging test method. And measured the T _B at that time.

5) Appearance 6) Feeling when foam was pressed with a finger In the table, ◎: good, ：: good, Δ: acceptable, ×: unacceptable.

Claims (1)

(57) [Claims] When a flexible polyurethane foam is obtained from an organic diisocyanate, a polyester polyol, a blowing agent, a catalyst and a surfactant, the polyester polyol comprises: a dicarboxylic acid mixture containing at least 50 mol% of sebacic acid as an acid component; As polyhydric alcohol components, (a) trimethylolpropane, (b) diethylene glycol, (c) 1,6-hexanediol and / or 3-methyl-1,5-pentanediol are combined with (b) and (c). Molar ratio of 40-80 mol%: 60
Number average molecular weight obtained by reaction at ~ 20 mol% 1000 ~
A method for producing a moisture-and-heat-resistant flexible polyurethane foam, which has a molecular weight of 4000 and an average number of functional groups of 2.2 to 4.0.