JP2003335834A - Flexible polyurethane foam and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a flexible polyurethane foam without using an ozone-layer depleting substance, e.g. a CFC, as a blowing agent while reducing the amount of heat generated during foaming; and a low- density flexible polyurethane foam having a high hardness obtained by the method. <P>SOLUTION: In this method for producing a flexible polyurethane foam by using raw materials including a polyol, a polyisocyanate, and water, 5-50 pts.mass water is used based on 100 pts.mass polyol and the isocyanate index is 30 or higher but lower than 80. Assuming that all the polyol reacts with the polyisocyanate, the ratio of the stoichiometric amount of water reacted with the polyisocyanate to the balance obtained by subtracting the compounding amount of water by the stoichiometric amount of reacted water is preferably 0.10-6.0. The flexible polyurethane foam produced by the method has a density of 4-30 kg/m<SP>3</SP>and a hardness of 50-150 N. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flexible polyurethane foam and a method for producing the same. More specifically, it relates to a flexible polyurethane foam having a low density and a high hardness, which does not use an ozone depleting substance such as CFC (chlorofluorocarbon) as a foaming agent, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a flexible polyurethane foam has a density of 10 to 50 kg / m ³ , and particularly 14 to 25.
Those having a kg / m ³ and a JIS hardness of 50 to 130 N are generally manufactured. Such polyurethane foams are widely used in applications such as vehicles, electric / electronics, and civil engineering. Further, such a flexible polyurethane foam is obtained by reacting a polyol and a polyisocyanate in the presence of a foaming agent, but in recent years,
In order to save raw materials and reduce costs, further reduction in density of flexible polyurethane foam has been studied. However, when the density of the flexible polyurethane foam is lowered, the hardness tends to be lowered, and studies have been conducted to increase the density and hardness of the flexible polyurethane foam (JP-A-07-5).
8372 publication).

On the other hand, in the production of flexible polyurethane foam, CFC has been used as a foaming agent, but since this substance is an ozone depleting substance, it was abolished at the conclusion of the Montreal Convention in 1987 and the social climate thereafter. It was decided to be done. Therefore, today, alternative substances such as HCFC (hydrochlorofluorocarbon), which are less likely to destroy the ozone layer than CFCs, are used as blowing agents. However, this HCFC is also planned to be completely abolished in the near future, and further studies are being conducted (Japanese Patent Laid-Open No. 07-107,071).
-58373 publication). Further, it has been proposed to reduce the density by adding a large amount of water as a foaming agent, but intense internal heat is generated due to the reaction heat when foaming the foam raw material, and a scorch called a scorch occurs, There is a risk of fire.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and does not use an ozone depleting substance such as CFC as a foaming agent and produces a flexible polyurethane foam which generates less heat during foaming. An object of the present invention is to provide a method and a flexible polyurethane foam obtained by the method, which has a low density and a high hardness.

[0005]

Means for Solving the Problems In the production of polyurethane foam using water as a foaming agent, the present inventors have
Excessive addition of water to the polyol, and a specific isocyanate index, reduce heat generation due to reaction heat during foam production, lower density, and higher density than is generally used. The inventors have found that a flexible polyurethane foam having hardness can be produced, and completed the present invention.

The method for producing a flexible polyurethane foam of the present invention is a method for producing a flexible polyurethane foam using a foam raw material containing a polyol, a polyisocyanate, and water, wherein the amount of the polyol is 100 parts by mass. The water is 5 to 50 parts by mass, and the isocyanate index is 30 or more and less than 80. The polyol has a number average molecular weight of 1200 to 8000 and an equivalent weight of 30.
The manufacturing method may be 0 to 4000. Further, the above-mentioned isocyanate index can be a production method of 30 to 75. Also, the water is 7 to 5
The production method can be 0 parts by mass. Furthermore, in the case where all of the above-mentioned polyols react with the above-mentioned polyisocyanate, the stoichiometric amount of water reacting with the polyisocyanate and the excess amount of water obtained by subtracting the reaction amount from the blending amount of water The ratio (excess / reaction) is 0.10-6.
The manufacturing method may be 0. The flexible polyurethane foam of the present invention is manufactured by the above method, and is characterized by having a foam density of 4 to 30 kg / m ³ and a foam hardness of 50 to 150 N.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
As the "polyol", a polyether polyol obtained by adding an alkylene oxide to an initiator is used. Further, a modified product (polymer polyol) obtained by reacting this polyether polyol with an ethylenically unsaturated monomer may be used. Examples of the initiator include ethylene glycol, propylene glycol, glycerin, trimethylolpropane, hexanetriol, pentaerythritol, erythritol, diglycerin, sorbitol, sucrose, monoethanolamine, diethanolamine and triethanolamine. These may be used alone or in combination of two or more. As the alkylene oxide, ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO) and the like are used. These may be used alone or in combination of two or more. In addition, this addition reaction is usually 5
It is carried out in the temperature range of 0 to 200 ° C., and the alkylene oxide is added in the form of random and / or block. The polymer polyol can be obtained by polymerizing an ethylenically unsaturated monomer in a polyether polyol according to a conventional method. As the ethylenically unsaturated monomer, acrylonitrile, acrylamide, acrylic acid ester, methacrylic acid ester, vinyl acetate, styrene and the like are used. These may be used alone or 2
You may mix and use 1 or more types.

The number average molecular weight of the polyol is not particularly limited as long as it can form a foam, but it is 1200 to 80.
It is preferably 00, more preferably 1500 to
7,000, and more preferably 1500 to 6000.
When the number average molecular weight is in the range of 1200 to 8000, it is possible to obtain a foam having good cushioning properties such as no cleavage. The equivalent weight of the polyol (molecular weight per hydroxyl group) is not particularly limited, but is preferably 300 to 4000, more preferably 400 to 3500, further preferably 500 to 30.
00. When the equivalent weight is in the range of 300 to 4000, a foam having good cushioning properties can be obtained. Further, in the present invention, the number average molecular weight is 1200 to 8000 and the equivalent weight is 300 to 4
000 polyol, especially 1500 in number average molecular weight
To 7,000 and the equivalent weight is 400 to 3500, and further the number average molecular weight is 1500 to 60.
The use of a polyol having a weight average molecular weight of 00 and an equivalent weight of 500 to 3,000 allows a foam having better cushioning properties to be obtained.

The above-mentioned "polyisocyanate" is not particularly limited and, for example, various aromatic, aliphatic and alicyclic polyisocyanates can be used. Examples of the aromatic polyisocyanate include tolylene diisocyanate (TDI), crude TDI, 4,4′-diphenylmethane diisocyanate (MDI), crude MDI, 1,5-naphthalene diisocyanate, paraphenylene diisocyanate, and m-xylene diisocyanate. To be As the aliphatic polyisocyanate, 1,6-hexamethylene diisocyanate (HDI), crude HDI,
2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc. are mentioned. Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated MD.
I etc. are mentioned. These may be used alone or 2
You may mix and use 1 or more types. When used together,
Any of aromatic series, aliphatic series, and alicyclic series may be combined.

The compounding amount of polyisocyanate is appropriately adjusted by a predetermined isocyanate index. This isocyanate index is 30 or more, 8
It is less than 0, more preferably 30 to 75, further preferably 30 to 70, and particularly preferably 30 to 60. If the isocyanate index is less than 30, foaming may not be performed normally, cracking may occur, or foam may collapse. On the other hand, when it is 80 or more, the heat generation temperature at the time of foaming becomes high, and the possibility of spontaneous ignition increases. Further, the amount of carbon dioxide generated by the reaction between water and polyisocyanate increases, and a foam having good cushioning properties cannot be obtained. The isocyanate index means the percentage of the actual blending amount with respect to the necessary amount calculated by the stoichiometry of polyisocyanate that reacts with all active hydrogen contained in the polyol or the like in the foam raw material. For example, the isocyanate index 30 is a polyisocyanate equivalent to 30% in mass percentage with respect to the stoichiometrically necessary amount necessary to react with all active hydrogen contained in the polyol or the like in the foam raw material. Means being done.

The above "water" is not particularly limited, and for example, ion exchanged water, tap water, distilled water and the like are used. The blending amount of water is 5 to 50 parts by mass, more preferably 7 to 5 parts by mass, when the polyol is 100 parts by mass.
The amount is 0 parts by mass, more preferably 10 to 50 parts by mass, and particularly preferably 15 to 35 parts by mass. In the present invention, the amount of water to be added is 5 to 50 parts by mass, which is larger than the amount of water generally used as a foaming agent. Therefore, the internal heat generated at the time of foaming is removed by excessive water vaporization. It can be sufficiently reduced by heat. Further, if the amount of water blended is less than 5 parts by mass, heat generation during foaming cannot be sufficiently suppressed. In addition, it may not be possible to sufficiently reduce the density. On the other hand, when it exceeds 50 parts by mass, the amount of carbon dioxide generated by the reaction between water and polyisocyanate increases, and a predetermined foam cannot be formed.

Further, in the present invention, the polyol is 1
When the amount of water is 00 parts by mass, the amount of water is 5 to 50 parts by mass, and the isocyanate index is 30 or more, 8
It can be less than zero. Further, the blending amount of water is 7 to 50 parts by mass, the isocyanate index is 30 to 75, particularly the blending amount of water is 10 to 50, and the isocyanate index is 30 to 70, and further, the blending amount of water is The isocyanate index may be 15 to 35 and the isocyanate index may be 30 to 60. With such a range, a foam having a lower density and a higher hardness can be obtained.

The stoichiometric amount of water reacting with the polyisocyanate calculated assuming that all of the polyols react with the polyisocyanate, and the water amount obtained by subtracting the reaction amount from the actual blending amount of water. The ratio (excess amount / reaction amount) with respect to the excess amount is preferably 0.10 to 7.0, more preferably 0.20 to 6.5, and further preferably 0.50 to 6.0. . When this value is less than 0.10, the proportion of water involved in cooling is small, and heat generation during foaming may not be suppressed in some cases. On the other hand, if this value exceeds 7.0, the amount of carbon dioxide generated by the reaction between water and polyisocyanate becomes too large, and it may not be possible to form a predetermined foam.

Further, the foam raw material may contain, in addition to polyol, polyisocyanate and water, a catalyst, a foam stabilizer such as a silicon foam stabilizer, a foaming aid such as methylene chloride and the like. Further, other auxiliary agents and the like can be contained as necessary. Examples of the auxiliaries include flame retardants, antioxidants, ultraviolet absorbers, coloring agents, and various diluents for lowering the viscosity of foam raw materials and facilitating stirring and mixing. These can be contained in appropriate amounts within a range that does not impair the effects of the present invention.

Further, in the method for producing a polyurethane foam of the present invention, the exothermic temperature during foaming is 160
The temperature can be set to not more than 0 ° C, particularly not more than 150 ° C, and further not more than 140 ° C. Therefore, the occurrence of scorch can be suppressed and the risk of fire can be reduced.

The flexible polyurethane foam of the present invention is produced by the above method and has a foam density of 4 to 30 k.
g / ^{m 3,} and the hardness of the foam can be assumed to be 50～150N. Also, the foam density is 5
25 kg / m ³ and foam hardness of 60 to 150 N
Can be Further, the foam has a density of 5 to 20 kg / m ³ and a foam hardness of 70 to 1
It can be 50N.

[0017]

The present invention will be described in more detail with reference to the following examples. (1) Raw material used (A) Polyol Sanyo Kasei Co., Ltd., trade name "GP3000",
Number average molecular weight: 3000, equivalent weight: 1000, manufactured by Sanyo Chemical Industries, Ltd., trade name "GP1500",
Number average molecular weight: 1,500, equivalent weight: 500 manufactured by Asahi Denka Kogyo Co., Ltd., trade name "G700", number average molecular weight: 700, equivalent weight: 234 manufactured by Asahi Glass Co., Ltd., trade name "Preminol 700"
5 ", number average molecular weight: 7,000, equivalent weight: 2330 (B) Polyisocyanate TDI; Nippon Polyurethane Co., Ltd., trade name" T- "
80 "MDI; manufactured by Nippon Polyurethane Co., Ltd., product name" MR
200 "(C) Foaming agent water (ion exchanged water) (D) Catalyst Sankyo Air Products Co., Ltd., trade name" 33LV "Johoku Chemical Co., Ltd., trade name" MRH110 "(E) Surfactant (foam stabilizer) ) Toray Dow Corning Silicone Co., Ltd., trade name "SF2961" Gold Schmidt, trade name "B8110"

(2) Experimental Examples 1 to 8 for Production of Flexible Polyurethane Foam According to the formulations shown in Table 1, each component except polyisocyanate was first agitated in a predetermined amount ratio using a hand mixer. Then, polyisocyanate [and its mixture (ratio; 50/50), NCO%; 39.45%] was blended according to a predetermined isocyanate index, and 540 g of this mixture was foamed in a foam box (length 300 mm, width 400 mm, height 400 mm). Then, it was foamed and cured to produce a flexible polyurethane foam. Further, when the raw material was foamed and the height of the foam became stable, a sheath-type K thermocouple connected to a recorder (Yokogawa Electric Co., Ltd., model number “4176”) was inserted, and The temperature was measured at a position 150 mm from the bottom at the center, and the peak value was used as the internal temperature, and the results are shown in Table 2.

The "excess amount / reacted amount" in the "Water" column shown in Table 1 is the stoichiometric amount of water with the polyisocyanate calculated assuming that all of the polyols react with the polyisocyanate. The ratio (excess amount / reaction amount) of the reaction amount of 1 to the excess amount of water obtained by subtracting the reaction amount from the actual blending amount of water is shown. For example, in Experimental Example 1, this ratio (excess amount /
The reaction amount) can be calculated as follows. First, since the NCO% of the polyisocyanate used is 39.45%, the isocyanate equivalent weight is 106.46 [42
(Molecular weight of NCO group) × 100 / 39.45 = 106.
46]. Next, polyol (equivalent weight 500)
The amount of polyisocyanate required stoichiometrically with respect to 100 parts by mass is 21.29 parts by mass [(106.46 / 50
0) × 100 = 21.29]. In addition, used water 7
The amount of polyisocyanate required stoichiometrically with respect to parts by mass is 82.80 parts by mass [7 × 106.46 / 9 (water equivalent) = 82.80]. Therefore, when the isocyanate index is 100, the polyisocyanate is 104.09 parts by mass (21.29 + 82.80 = 10).
4.09) Required. Then, in Experimental Example 1,
Since this isocyanate index is set to 32, the required amount of polyisocyanate is 33.31 parts by mass (104.09 × 0.32 = 33.31). Here, assuming that all of the polyol reacts with the polyisocyanate, the water is the rest of the polyisocyanate 12.
02 parts by mass (33.31-21.29 = 12.02). Therefore, out of 7 parts by mass of water,
1.02 parts by mass (12.02 × 9 / 106.46 = 1.
02) becomes the reaction amount, and the remaining 5.98 parts by mass (7-
1.02 = 5.98) is an excess amount. Therefore, the value of excess amount / reaction amount is 5.9 (5.98 / 1.02 = 5.9)
Is calculated.

(3) Evaluation of Foams The physical properties (density and hardness) of each of the obtained foams are determined by JIS.
The results are also shown in Table 2 as measured according to K 6400.

[0021]

[Table 1]

[0022]

[Table 2]

(4) Effects of the embodiment According to Table 1 and Table 2, the blending amount of water is 48 parts by mass, and
The isocyanate index is 87, which is within the range of the present invention.
In Experimental Example 3, which is outside the environment, the density of the foam is 4.1 kg.
/ M^ThreeAnd the hardness was 147 N, but when foaming
The internal temperature was as high as 182 ° C. In addition, the amount of water
7.0 parts by mass and isocyanate index of 85
In Experimental Example 4, which is outside the scope of the present invention,
Has a density of 11.3 kg / m ^ThreeAnd the hardness is 118
However, the internal temperature during foaming was as high as 165 ° C.
It was

Further, in Experimental Example 8 in which the blending amount of water was 60 parts by mass and the isocyanate index was 60, which was outside the range of the present invention, the density of the foam was 10.5 kg /
Although it was m ³ , the hardness could not be measured because the polyurethane foam was extremely brittle, and the hardness was not sufficient. The exothermic temperature during foaming was 120 ° C. Further, in Experimental Example 7 (outside the range of the present invention) in which the compounding amount of water is 5 parts by mass and the isocyanate index is 100, which is a conventional general compounding ratio, the foam density is 20.3 kg / m ³ , and The hardness was 70 N, and the polyurethane foam had low density and high hardness. But,
The internal temperature during foaming was as high as 163 ° C.

On the other hand, in Experimental Examples 1, 2, 5 and 6 in which the blending amount of water is 7 to 48 parts by mass and the isocyanate index is 32 to 50, the foam density is 6.2.
~28.5kg / ^{m 3,} and the hardness is 53～101N, was a low-density, high hardness polyurethane foam.
Particularly, in Experimental Examples 2, 5 and 6, the foam has a density of 6.2 to 8.7 kg / m ³ and a hardness of 53 to 81 N.
The hardness was equal to or higher than that of Experimental Example 7 in spite of the low density. In addition, Experimental Example 1,
The internal temperature during foaming in 2, 5 and 6 was 1
It was 03-144 degreeC. Among them, in Experimental Examples 1, 2, 5 and 6 in which the ratio of the excess amount of water to the reaction amount (excess amount / reaction amount) was 1.0 or more, the internal temperature during foaming was 10
It was 3 to 144 ° C, which was sufficiently lower than that of Experimental Example 7 (163 ° C).

[0026]

According to the production method of the present invention, a flexible polyurethane foam having a low density and a high hardness can be obtained without using an ozone depleting substance such as CFC as a foaming agent, and heat generated during foaming. Is also suppressed. Further, when the number average molecular weight and the equivalent weight of the polyol are set to specific values, it is possible to obtain a flexible polyurethane foam having low density, high hardness and excellent cushioning properties. Furthermore, when the isocyanate index is set to a specific value, the internal temperature during foaming can be further lowered, and a flexible polyurethane foam having excellent cushioning properties can be obtained. Further, when the water content is set to a specific value, the internal temperature due to the reaction heat during foaming can be further lowered, and a flexible polyurethane foam having a lower density can be obtained. Furthermore, when the ratio of the stoichiometric amount of water that reacts with polyisocyanate and the excess amount of water that is obtained by subtracting this reaction amount from the actual amount of water is set to a specific value, It is possible to further suppress heat generation. Since the polyurethane foam of the present invention is produced by the above method, the foam density can be 4 to 30 kg / m ³ , and the foam hardness can be 50 to 150 N.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kimihiko Abe             Aichi Prefecture Anjo City Imaike Town 3 1-336 Stock             Inoac Corporation Anjo Business             In-house F-term (reference) 4J034 BA03 CE01 DA01 DB04 DC50                       DG03 DG04 DG05 DQ02 HA01                       HA07 HC03 HC12 HC13 HC17                       HC22 HC46 HC52 HC61 HC64                       HC67 HC71 HC73 NA03 NA08                       QA03 QA05 QB01 QB15 QC01                       QC08

Claims (6)

[Claims] 1. A polyol and a polyisocyanate,
A method for producing a flexible polyurethane foam using a foam raw material containing water, wherein the polyol is 100
The above water is 5 to 50 parts by mass when defined as parts by mass,
And the isocyanate index is 30 or more and less than 80, The manufacturing method of flexible polyurethane foam characterized by the above-mentioned. 2. The number average molecular weight of the polyol is 12
0 to 8000 and an equivalent weight of 300 to 400
The method for producing a flexible polyurethane foam according to claim 1, which is 0. 3. The isocyanate index is 30.
The method for producing a flexible polyurethane foam according to claim 1 or 2, wherein 4. The water is 7 to 50 parts by mass.
4. The method for producing a flexible polyurethane foam according to any one of items 1 to 3. 5. When all of the above-mentioned polyols react with the above-mentioned polyisocyanate, stoichiometric reaction amount of water with the above-mentioned polyisocyanate and excess amount of water obtained by subtracting the reaction amount from the blending amount of water. Ratio with amount (excess amount / reaction amount)
Is 0.10-6.0, The manufacturing method of the flexible polyurethane foam according to any one of claims 1 to 4. 6. A foam produced by the method according to any one of claims 1 to 5 having a density of 4 to 30.
kg / ^{m 3,} a flexible polyurethane foam and the hardness of the foam characterized in that it is a 50～150N.