JP2002105163A - Flexible polyurethane foam having resistance to moist heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible polyurethane foam excellent in touch feeling having resistance to moist heat. SOLUTION: This polyurethane foam having resistance to moist heat is obtained by using a polyester polyol composed of a polyhydric alcohol component in which 2-methyl-1,3-propanediol is used in an amount of >=20 mol% based on polyhydric alcohol and a dicarboxylic cid component and having 500-5,000 number-average molecular weight and 2.0-4.0 number-average functional groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible polyurethane foam, and more particularly to an inexpensive, highly moist and heat-resistant flexible polyurethane foam using a polyester polyol containing a specific polyhydric alcohol component. is there.

[0002]

2. Description of the Related Art It is known that a so-called sebacic acid-based polyester polyol obtained by reacting sebacic acid with an aliphatic glycol is excellent in hydrolysis resistance. A poly (hexamethylene adipate) -based polyester polyol derived from adipic acid and 1,6-hexanediol is poly (ethylene adipate).
It is also well known that polyester polyols are superior in hydrolysis resistance to polyester polyols such as poly (propylene adipate), poly (diethylene adipate), and poly (butylene adipate). However, sebacic acid-based polyester polyol and poly (hexamethylene adipate) -based polyester polyol have high crystallinity,
Use alone on flexible polyurethane foams was not practical. In other words, in many cases, the polyurethane foam does not have a liquid property at room temperature, and even if it is heated to be in a liquid state to form a polyurethane foam, shrinking and sinking are not realistic. Also, an adipic acid-based polyester polyol using neopentyl glycol in combination with 1,6-hexanediol has been proposed, but even if a slight improvement in physical properties is made, there is no effect of suppressing crystallinity.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have developed polyesters having excellent hydrolysis resistance and non-crystallinity, such as sebacic acid-based polyester polyols and poly (hexamethylene adipate) -based polyester polyols. As a result of earnestly searching for and examining polyols, they have found that the use of a specific polyester polyol can provide the desired moist heat-resistant flexible polyurethane foam, thereby completing the present invention.

[0004]

That is, the present invention relates to a flexible polyurethane foam formed from a diisocyanate compound, a polyester polyol, a blowing agent, a catalyst and a surfactant.
Containing -methyl-1,3-propanediol as a polyhydric alcohol component, having a number average molecular weight of 500 to 5,000,
The present invention relates to a moisture-and-heat-resistant flexible polyurethane foam having a number average functional group number of 2.0 to 4.0.

In the present invention, the polyhydric alcohol component constituting the polyester polyol is 2-methyl-1,3
-It must be based on propanediol.

[0006] The polyester polyol which is a raw material for obtaining the moist heat-resistant flexible polyurethane foam of the present invention comprises:
Low in crystallinity, liquid at room temperature, easy to handle,
Processing into flexible polyurethane foam is easy. The wet heat resistance of the obtained flexible polyurethane foam is higher than that of a flexible polyurethane foam made from polyester polyol obtained from the reaction of trimethylolpropane and diethylene glycol with adipic acid, which is currently mainly used as a raw material for flexible polyurethane foam. Is also much better.

The polyester polyol of the present invention can be prepared by subjecting a polyhydric alcohol and a polycarboxylic acid to an esterification reaction under normal pressure, a method of performing an esterification reaction under a vacuum, or a method in which an inert solvent such as toluene is used. After performing an esterification reaction, a condensed water and a solvent can be azeotropically removed to remove them from the reaction system.

In any case, it is desirable to carry out the reaction in the presence of a catalyst from the viewpoint of promptly proceeding the esterification reaction.
In addition to metal compounds such as titanium, zinc, tin, lead and iron, organic sulfonic acids such as paratoluenesulfonic acid can be applied. Of these, titanium-tetra-alkoxides such as titanium-tetra-isopropoxide are preferred, and the amount of these catalysts used is suitably as low as 5 to 50 ppm. The reaction temperature at this time is usually in the range of 100 to 250 ° C.

The number average molecular weight of the polyester polyol of the present invention is from 500 to 5,000. When the number average molecular weight of the polyester polyol is less than 500, the foaming stability during foam production becomes poor, and the mechanical properties of the foam become poor. On the other hand, when the molecular weight of the polyester polyol is 5
When it is larger than 000, the viscosity becomes high, and in the production of a flexible polyurethane foam, the mixing becomes insufficient, and the physical properties of the obtained foam tend to deteriorate.

As the polyhydric alcohol component used in the present invention, 2-methyl-1,3-propanediol is an essential component, but diethylene glycol, ethylene glycol, propylene glycol, 1,4-butanediol, 6-hexanediol, 3-methyl-1,5-
Pentanediol, 2-butyl-2-ethyl-propanediol, 1,4-cyclohexanedimethanol, 1,
Aliphatic polyhydric alcohols such as 9-nonanediol, trimethylolpropane and pentaerythritol and alicyclic polyhydric alcohols may be used in combination.

2-Methyl-1,3-propanediol improves moisture-heat resistance and is effective for liquefaction at room temperature.
It is desirable to use 100 mol%. If it is less than 20 mol%, the wet heat resistance will not be sufficiently improved, or it will tend to be solid at room temperature.

The number average functional group number of the polyester polyol of the present invention is from 2.0 to 4.0. Polyhydric alcohols such as trimethylolpropane and pentaerythritol can be used for adjusting the number of functional groups.

When the number average functional group number is less than 2.0, the flexible polyurethane foam obtained from this polyester polyol has poor moisture and heat resistance, and when it exceeds 4.0, the polyester polyol has a high viscosity,
In the production of a flexible polyurethane foam, the mixing becomes insufficient, and the physical properties of the obtained foam tend to deteriorate.

The polybasic acid used in the present invention is not particularly limited, but may be aliphatic, alicyclic polybasic acids such as adipic acid, sebacic acid, dimer acid, 1,4-cyclohexanedicarboxylic acid, and terephthalic acid. Acids and aromatic polybasic acids such as isophthalic acid can be used. These polybasic acids may be used alone or in combination of two or more.

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

In this case, the ratio R (NCO / O) of the isocyanate equivalent to the active hydrogen equivalent in the diisocyanate compound is used.
H) is from 0.90 to 1.20, preferably from 0.95 to 1.
05. When this ratio is 0.90 or less, the molecular weight does not increase so much, and the tensile strength,
Inferior mechanical properties such as ultimate elongation and tear resistance,
When R is 1.2 or more, the degree of crosslinking of the flexible polyurethane structurally increases significantly, and the ultimate elongation rate generally decreases significantly.

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

A typical example of the 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, pentamethylenediethylenetriamine, dimethylethanolamine and ethylmorpholine, dibutyltin dilaurate, dioctyltin laurate, stannas octate, and octenes of various metals. There are metal catalysts such as acid salts, and all of the above catalysts can be used as a mixture.

As the surfactant which can be used in the present invention, any surfactant which is effective for producing a polyurethane foam can be used. Examples include polyoxyalkylene-based ones such as polyoxyalkylene alkyl ether and polyoxyalkylene alkylamino ether, and silicone-based ones such as organopolysiloxane and siloxane oxyalkylene copolymer.

Examples of the additives that can be used as needed include antioxidants and antioxidants such as ultraviolet absorbers, fillers such as calcium carbonate and barium sulfate,
Known in the art, such as a flame retardant, a plasticizer, a colorant, and an antifungal agent.

The reaction conditions for the formation of the flexible polyurethane are as follows: the above-mentioned R is kept constant, and a one-shot method in which predetermined raw materials are simultaneously charged, and the remaining raw materials are added to a prepolymer obtained by reacting a polyester polyol and a diisocyanate compound and reacted. 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 machine.

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 thus produced can be used as a foamed foam for general use such as clothing and footwear, and for industrial and industrial use.

[0026]

According to the present invention, when the specific polyester polyol described in the present invention is used, the obtained flexible polyurethane foam has an excellent texture and a good wet heat resistance.

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 Polyester Polyol 1460 g of adipic acid, 2-methyl-1,3-propanediol were placed in a 3 L reaction vessel equipped with a partial condenser, a stirrer, a heating / cooling jacket, a nitrogen gas introducing pipe, and a pressure reducing line. 922 g, trimethylolpropane 78
After charging a total amount of 2,460 g, 50 mg of tetra-n-butyltitanium is charged as an esterification reaction catalyst and the temperature is raised to 130 ° C. while 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 that the polyhydric alcohol component does not distill out of the reaction system. Thereafter, the temperature is maintained at 210 ° C. until no more water distills. Then 210
The pressure was reduced to 20 mmHg while maintaining the temperature at 0 ° C, and it was confirmed by sampling that the acid value had become 1.0 or less, and the reaction contents were cooled to room temperature. Thus, a viscous polyester polyol 1 at room temperature was obtained. Polyester polyol 1 has a hydroxyl value (OHV) of 60 and an acid value (AV)
0.4, the number of functional groups was 2.7, and the molecular weight was 2500.

Production of Flexible Polyurethane Foam <Blending Formula> 100 parts by weight of polyester polyol 1 4.0 parts by weight of water 1.5 parts by weight of silicone L532 (Nippon Unicar Co., Ltd.) 21 (Kao Corporation) 1.0 part by weight Stanas octoate 0.01 part by weight Coronate T-80 (Tolylene diisocyanate manufactured by Nippon Polyurethane Co.) R (NCO / OH) = 1.05

The temperature of each liquid used in the above formulation is adjusted to 20.
℃, put each liquid in one polyethylene cup, stirrer (TK homodisper SL type manufactured by Tokushu Kika Kogyo Co., Ltd.)
The mixture was mixed at a rotation speed of 4000 rpm, and was quickly transferred to a box type having an opening at the top of 250 × 250 × 250 mm, and free-foamed. The mold temperature is 20 ° C.

The wet heat resistance of the obtained flexible polyurethane foam was evaluated by the method of the wet heat aging test (reference) of JIS K-6401-1980, and the tensile strength after 6 hours, 12 hours and 24 hours was measured. The comparison was made with the tensile strength of

The compression set is also determined by JISK-
It was measured by a compression set test method of No. 6401-1980, and was performed by comparing with a comparative example.

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

Example 2 1775 g of a mixed dicarboxylic acid of 745 g (50 mol%) of adipic acid and 1030 g (50 mol%) of sebacic acid, 920 g of 2-methyl-1,3-propanediol, and 117 of trimethylolpropane
g of 2850, the number of functional groups of 3.0, and the OHV of 60.g in the same manner as in Example 1 except that a total amount of 2812 g was used.
5. A viscous polyester polyol 2 was synthesized at room temperature of AV 0.4.

Using this polyester 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 1460 g of adipic acid and 2
-Butyl-2-ethyl-propanediol 800 g (5
0 mol%) and 2-methyl-1,3-propanediol 4
Normal temperature of 2780 molecular weight, 3.0 functional groups, 59.4 OHV, 0.4 AV in the same manner as in Example 1 except that the total charged amount of 50 g (50 mol%) of the mixed glycol and 118 g of trimethylolpropane was 2828 g. To synthesize a viscous polyester polyol 3.

Using this polyester 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 1460 g of adipic acid, 2-
A mixed diol of 1120 g (76 mol%) of methyl-1,3-propanediol and 354 g (24 mol%) of 1,6-hexanediol and 129 g of trimethylolpropane
The molecular weight was 2780, the number of functional groups was 3.0, and the OHV5 was the same as in Example 1 except that the total charge amount of 3063 g was used.
9.4, a viscous polyester polyol 4 was synthesized at room temperature of AV 0.4.

Using this polyester 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 A total charge of 1738 g of adipic acid, 1036 g of 2-methyl-1,3-propanediol and 154 g of trimethylolpropane was 2928.
g of 324 in the same manner as in Example 1 except that g was used.
A viscous polyester polyol 5 was synthesized at room temperature with 0, 3.5 functional groups, OHV 60.6 and AV 0.3.

Using this polyester 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.

Comparative Example 1 1412 g of adipic acid, 1,
The total charge of 1435 g of 6-hexanediol is 28
A molecular weight of 10 was obtained in the same manner as in Example 1 except that 47 g was used.
00, a polyester polyol having 2.0 functional groups was obtained. This polyester polyol is solid at room temperature,
Flexible polyurethane foam could not be produced.

Comparative Example 2 1553 g of adipic acid, 1,
A mixture of 878 g (70 mol%) of 6-hexanediol and 332 g (30 mol%) of neopentyl glycol and 120 g of trimethylolpropane was used in the same manner as in Example 1 except that a total charge of 2883 g was used, and the molecular weight was 2800, and Radix 3.0, OHV60.2, AV
A polyester polyol of 0.5 was obtained. This polyester polyol was solid at room temperature, and a flexible polyurethane foam could not be produced.

[Comparative Example 3] Polyester polyol (molecular weight: 2520, functional group: 2.6) mainly composed of adipic acid, trimethylolpropane and diethylene glycol, which is mainly used for the production of a flexible polyurethane foam
5, OHV 60.5, AV 0.8) as raw materials, and a flexible polyurethane foam was produced by free foaming 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.

COMPARATIVE EXAMPLE 4 A mixed diol of 1610 g of adipic acid, 840 g (70 mol%) of diethylene glycol and 353 g (30 mol%) of neopentyl glycol and a total charge of 93 g of trimethylolpropane were 28.
Except that 96 g was used, the number average molecular weight was 2500, the average number of functional groups was 2.7, OHV was 60.6, and A was the same as in Example 1.
A viscous polyester polyol 6 was obtained at room temperature of V0.4.

Using this polyester 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.

[0047]

[Table 1]

From the results shown in Table 1, it can be seen that the flexible polyurethane foams of the present invention of Examples 1 to 5 are excellent in texture and wet heat resistance. On the other hand, the flexible polyurethane foams of Comparative Examples 3 and 4, which are different from the flexible polyurethane foams of the present invention, are inferior in texture and have the same initial physical properties, but the change in tensile strength after the wet heat aging test is significantly poor. The result was seen.
Further, the polyester polyols of Comparative Examples 1 and 2 were solid at room temperature, and a flexible polyurethane foam could not be produced.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koichi Akiyama 3-8-40 Kitadamiya, Tokushima City, Tokushima Prefecture Inside the Tokushima Plant, Hitachi Chemical Polymer Co., Ltd. (72) Inventor Hiroshi Hashimoto 3-8 Kitadamiya, Tokushima City, Tokushima Prefecture No. 40 Hitachi Chemical Polymer Co., Ltd. Tokushima Plant F-term (reference) 4J034 BA03 CE01 DA01 DB03 DF01 DF14 DF15 DF16 DM01 DM09 HA01 HA06 HA07 HC01 HC02 HC03 HC12 HC13 HC22 HC46 HC52 HC61 HC63 HC64 HC66 HC67 HC71 HC73 KA01 KC08 KC16 KC KC35 KD04 KD12 KD22 LA08 MA12 NA01 NA03 QA02 QA05 QB12 QB15 QC01 RA03 RA09

Claims (2)

[Claims] 1. A flexible polyurethane foam formed from a polyester polyol, a diisocyanate compound, a blowing agent, a catalyst and a surfactant, wherein the polyester polyol contains 2-methyl-1,3-propanediol as a polyhydric alcohol component. Number average molecular weight 500-
5000, a moisture-heat-resistant flexible polyurethane foam having a number average functional group number of 2.0 to 4.0. 2. The moisture and heat resistant polyurethane foam according to claim 1, wherein 2-methyl-1,3-propanediol is contained in an amount of 20 to 100 mol% of the entire polyhydric alcohol component.