JP2008094944A - Process for producing flexible polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a flexible polyurethane foam capable of exhibiting excellent breathability while maintaining mechanical properties. <P>SOLUTION: The flexible polyurethane is produced by reacting and foaming a raw material of a flexible polyurethane foam comprising polyols, polyisocyanates, a catalyst, a blowing agent, and auxiliary blowing agent. In this instance, a liquefied carbon dioxide gas is used as the auxiliary blowing agent in an amount of 2.0-5.0 pts.mass per 100 pts.mass polyols. A metal catalyst is used as the catalyst and its content is set at 0.05-0.15 pt.mass per 100 pts.mass polyols. Furthermore, the isocyanate index is set at 90-108. As the above catalyst, an amine catalyst of a foaming catalyst is preferred. The amine catalyst preferably has a ratio of the foaming catalyst constant to the gelling catalyst constant of 10×10<SP>-1</SP>to 40×10<SP>-1</SP>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a flexible polyurethane foam used as a material for forming an application requiring high air permeability, for example, a dust filter, an air conditioning sheet, or the like.

  In general, a flexible polyurethane foam produced by the slab foaming method has an open cell structure and exhibits better air permeability than a foam having a closed cell structure such as rubber sponge or polyethylene foam. Can do. However, when considering the use of various types of dust removal filters, air conditioning seats in which an air conditioner is incorporated in a seat cushion of an automobile, higher air permeability is required in order to reduce the load on the air conditioning equipment. Conventionally, there are mainly two methods for obtaining such a polyurethane foam having high air permeability.

  In the first method, post-treatment is performed after production of the polyurethane foam. Examples of the post-treatment include a method of performing heat treatment, ozone treatment, alkali treatment, and the like, a method of injecting oxygen and hydrogen into the foam, and removing the cell film by combustion energy. This first method can completely remove the cell membrane of the foam and obtain high air permeability, but may cause deterioration of the foam itself, resulting in poor durability of the foam, There is a problem that a large facility for post-processing is required and the production efficiency is low.

Therefore, the second method is a method that does not depend on such post-treatment, such as a method of mixing silica sol in a polyol, a method of mixing a polyether polyol and a polyester polyol, and a method of using a large amount of special diol (for example, patent documents). 1), and a method using liquefied carbon dioxide as an auxiliary foaming agent (see, for example, Patent Document 2). The method described in Patent Document 2 uses liquefied carbon dioxide as an auxiliary foaming agent and sets the isocyanate index to 110 to 120.
JP-A-7-2970 (pages 2 and 5) JP 2006-131755 A (page 2, page 6 and page 9)

  However, in the method that does not depend on the post-treatment as described in Patent Document 1, since a large amount of special diol is used, the foaming stability is hindered, and the foam is ruptured or collapsed to obtain a good foam. In some cases, especially in the case of foaming on a mass production scale, the foaming tends to vary and the cell membrane tends to remain, and the air permeability of the resulting foam is reduced. Moreover, in the method of patent document 2, since the isocyanate index is set high, the crosslinking density of a foam becomes high, a cell film becomes easy to be formed, and the air permeability of the obtained foam falls. In this case, if the isocyanate index is simply lowered, the crosslink density of the foam is lowered, and mechanical properties such as hardness and compression residual strain of the foam are deteriorated. Therefore, there is a need for a method for improving the air permeability while maintaining the mechanical properties of the foam.

  Accordingly, an object of the present invention is to provide a method for producing a flexible polyurethane foam capable of exhibiting excellent air permeability while maintaining mechanical properties.

  In order to achieve the above object, a method for producing a flexible polyurethane foam (hereinafter also simply referred to as a foam) according to claim 1 is a foam containing a polyol, a polyisocyanate, a catalyst, a foaming agent and an auxiliary foaming agent. This is a method for producing a flexible polyurethane foam by reacting and foaming body materials. In this case, 2.0 to 5.0 parts by mass of liquefied carbon dioxide is used as the auxiliary blowing agent per 100 parts by mass of polyols, and a metal catalyst is used as the catalyst, and the content is 0.05 per 100 parts by mass of polyols. The isocyanate index, which is expressed as a percentage of the equivalent ratio of the isocyanate group of the polyisocyanate to the active hydrogen group in the raw material, is set to 90 to 108.

The method for producing a flexible polyurethane foam according to claim 2 is the invention according to claim 1, wherein an amine catalyst is used as the catalyst, and the amine catalyst has a ratio of the foaming catalyst constant to the gelation catalyst constant of 10 × 10 ^−1. It is a foaming catalyst which is -40 * 10 < ^-1 >.

According to the present invention, the following effects can be exhibited.
In the method for producing a flexible polyurethane foam according to claim 1, since liquefied carbon dioxide gas is used as an auxiliary foaming agent, there is almost no solubility in the foam and there is no possibility of inhibiting the resinification reaction. Furthermore, since the vaporization of liquefied carbon dioxide gas already starts when mixing and discharging the foam material, the bubbles are more stable than those in the case of foaming from the liquid state, the cell film is difficult to form, and the metal catalyst for resinization Can be reduced. By using this liquefied carbon dioxide gas in an appropriate amount of 2.0 to 5.0 parts by mass per 100 parts by mass of polyols, foaming can be progressed in a stable state, and the air permeability of the resulting foam can be improved. Can do.

  Moreover, since a metal catalyst is used as a catalyst and the content thereof is 0.05 to 0.15 parts by mass per 100 parts by mass of polyols, the foam can be prevented from bursting and collapsing, and the formation of cell membranes can be suppressed. be able to. And by setting an isocyanate index to 90-108, while progressing foaming smoothly, resinification can be suppressed and a crosslinking density can be suppressed. Therefore, it is possible to produce a flexible polyurethane foam that can exhibit excellent air permeability while maintaining mechanical properties.

In the method for producing a flexible polyurethane foam according to claim 2, an amine catalyst having a ratio of the foaming catalyst constant to the gelation catalyst constant of 10 × 10 ⁻¹ to 40 × 10 ⁻¹ is used as a catalyst. The gelation catalyst constant is a constant that determines the speed of the resinification (gelation) reaction between polyols and polyisocyanates, and as the value increases, the crosslinkability of the foam increases and the cell connectivity decreases. The foaming catalyst constant represents a constant that determines the speed of the foaming reaction between the polyisocyanate and water as the foaming agent, and the larger the value, the higher the cell connectivity of the foam. Therefore, by using an amine catalyst whose ratio falls within the above range, in addition to the effect of the invention according to claim 1, the air permeability of the foam can be improved.

Hereinafter, embodiments of the present invention will be described in detail.
The method for producing a flexible polyurethane foam according to this embodiment is a method for producing a foam by reacting and foaming a foam raw material containing polyols, polyisocyanates, a catalyst, a foaming agent and an auxiliary foaming agent. In this case, liquefied carbon dioxide is used as an auxiliary foaming agent in an amount of 2.0 to 5.0 parts by mass per 100 parts by mass of polyols. Moreover, a metal catalyst is used as a catalyst, and the content is set to 0.05 to 0.15 parts by mass per 100 parts by mass of polyols. Furthermore, the isocyanate index is set to 90-108. A flexible polyurethane foam produced under such conditions can exhibit good breathability while maintaining required mechanical properties.

Next, the raw material of the foam will be described in order.
As the polyols, polyether polyols or polyester polyols are used. Examples of the polyether polyol include polypropylene glycol, polytetramethylene glycol, modified products thereof, and compounds obtained by adding alkylene oxide to glycerin. As polyester polyols, in addition to condensation polyester polyols obtained by reacting polycarboxylic acids such as adipic acid and phthalic acid with polyols such as ethylene glycol, diethylene glycol, propylene glycol and glycerin, lactone polyester polyols and polycarbonate systems A polyol is mentioned. These polyols can change the number of hydroxyl groups and the hydroxyl value by adjusting the kind of raw material components, the molecular weight, the degree of condensation, and the like.

  The hydroxyl value of the polyols is preferably 50 to 70 (mgKOH / g). By using a polyether polyol having such a hydroxyl value, it is possible to obtain a soft polyurethane foam that is excellent in reactivity with polyisocyanates and is appropriately crosslinked. When the hydroxyl value of polyols exceeds 70 (mgKOH / g), the crosslinking density becomes too high, the air permeability of the foam is lowered, and the hardness tends to be increased. On the other hand, when the hydroxyl value is less than 50 (mgKOH / g), the hydroxyl value becomes too small, and the crosslink density of the foam tends to be low, and the strength and hardness of the foam tend to decrease.

  A crosslinking agent can be mix | blended with a foam raw material. The crosslinking agent reacts with polyisocyanates and the like to form a crosslinked structure in the foam. For example, a polyol having a hydroxyl value of 250 to 650 (mg KOH / g) and a molecular weight of 150 to 500 is used. Specific examples of such polyols include polyethylene glycol, diethylene glycol, polypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like. Of these crosslinking agents, polyether diols such as polyethylene glycol, diethylene glycol, and polypropylene glycol are preferred. By using polyether diol, a structure in which the chain of the polymer forming the foam extends linearly is formed, and the flexibility of the foam can be improved.

  When the hydroxyl value of the crosslinking agent is less than 250 (mgKOH / g), the crosslinking reaction with the polyisocyanate is insufficient, and the crosslinking density of the foam is reduced. When it exceeds 650 (mgKOH / g), the crosslinking density of the foam increases due to excessive crosslinking reaction, and air permeability decreases. Further, when the molecular weight of the cross-linking agent is less than 150, the foam becomes too hard and the tactile feeling is impaired, and when it exceeds 500, the foam tends to be too soft. It is preferable that content of a crosslinking agent is 1-5 mass parts per 100 mass parts of polyols. When the content of the crosslinking agent is less than 1 part by mass, a sufficient crosslinked structure cannot be formed in the foam, and the mechanical strength of the foam tends to be insufficient. On the other hand, when it exceeds 5 parts by mass, the crosslinked structure of the foam becomes too dense and tends to lack air permeability.

  Next, polyisocyanates to be reacted with polyols are compounds having a plurality of isocyanate groups, specifically, tolylene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate ( NDI), triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI) and the like are used.

  The isocyanate index (isocyanate index) of polyisocyanates is set to 90-108. Here, the isocyanate index represents the equivalent ratio of the isocyanate group of the polyisocyanate to the active hydrogen group such as the hydroxyl group of the polyol, the hydroxyl group of the polyol as the crosslinking agent, and the foaming agent (water) in percentage. An isocyanate index exceeding 100 means that the isocyanate group is in excess of the active hydrogen group. When the isocyanate index is less than 90, the reaction of polyisocyanates with polyols and the like is insufficient, the foam tends to rupture and collapse, the crosslinking density of the resulting foam decreases, and the foam becomes soft Insufficient mechanical properties. On the other hand, if the isocyanate index exceeds 108, the cross-linking density of the foam is increased, the connectivity of the cells is deteriorated, and the soft touch as a flexible polyurethane foam cannot be obtained.

  The catalyst is for accelerating the resinification reaction (urethanization reaction) between polyols and polyisocyanates, and for promoting the foaming reaction between polyisocyanates and water as a blowing agent. In particular, a metal catalyst is used as the catalyst for selectively promoting the resinification reaction, and an amine catalyst is particularly used as a catalyst for promoting the foaming reaction. Specific examples of metal catalysts include organotin compounds such as tin octylate (tin octoate), dibutyltin dilaurate, tin dibutyldiacetate, tin di (2-ethylhexyl) dilaurate, and di (2-ethylhexanoate) tin. (2-ethylhexanoic acid) lead and the like. Of these, tin octylate is preferable in the one-shot method using a polyether polyol as the polyol. Specific examples of the amine catalyst include tertiary amines such as N, N ′, N′-trimethylaminoethylpiperazine, triethylenediamine, and dimethylethanolamine.

As the amine catalyst, in order to improve the air permeability of the foam, the ratio of the foaming catalyst constant to the gelation catalyst constant (hereinafter also referred to as catalyst constant ratio) is 10 × 10 ⁻¹ to 40 × 10 ^−1. It is preferable to use a catalyst. Here, the foaming catalyst means a catalyst having a strong tendency to generate carbon dioxide gas by promoting the reaction between polyisocyanates and water as a blowing agent. The resinification catalyst means a catalyst having a strong tendency to promote a resinification (gelation) reaction between a polyol and a polyisocyanate and generate a urethane bond.

The gelation catalyst constant is a constant that determines the speed of the resinification reaction between polyols and polyisocyanates. When the value increases, the crosslink density of the foam increases and the mechanical properties of the foam improve. . Specifically, the reaction constant of the gelation reaction between tolylene diisocyanate and diethylene glycol is used. On the other hand, the foaming catalyst constant is a constant that determines the speed of the foaming reaction between the polyisocyanates and water, and the larger the value, the higher the cell connectivity of the foam. Specifically, the reaction constant of the foaming reaction between tolylene diisocyanate and water is used. Therefore, the catalyst constant ratio is intended to balance these two catalyst constants. When the catalyst constant ratio is less than 10 × 10 ⁻¹ , the foaming reaction is insufficient and the cell connectivity tends to be poor. On the other hand, when the catalyst constant ratio exceeds 40 × 10 ⁻¹ , the resinification reaction is insufficient, and the mechanical properties represented by the hardness of the foam are lowered.

Specific examples of amine catalysts having a catalyst constant ratio in the above range include bis (2-dimethylaminoethyl) ether (catalyst constant ratio = 39.0 × 10 ⁻¹ ), N, N, N ′, N ″, N "- pentamethyldiethylenetriamine (catalytic constant ratio ^{= 37.3 × 10 -1), N} , N, N'- trimethyl aminoethyl ethanolamine (blowing catalyst ratio = 15.0 × ^{10 -1),} dimethylaminoethoxyethanol (Bubbling catalyst ratio = 13.9 × 10 ⁻¹ ) and the like.

  Content of the said metal catalyst is 0.05-0.15 mass part per 100 mass parts of polyols. When the content of the metal catalyst is less than 0.05 parts by mass, the progress of the resinification reaction is insufficient, the foam tends to rupture and collapse, the crosslink density of the resulting foam decreases, and the mechanical properties are reduced. Damaged. On the other hand, when the amount is more than 0.15 parts by mass, the resinification reaction proceeds excessively, the foam has a high crosslink density, the cell membrane increases, the cell connectivity is inhibited, and the air permeability deteriorates. . Moreover, it is preferable that content of an amine catalyst is 0.2-0.5 mass part per 100 mass parts of polyols. When the content of the amine catalyst is less than 0.2 parts by mass, the foaming reaction is not sufficiently progressed, and the connectivity of the cells of the resulting foam is lowered and the air permeability tends to be impaired. On the other hand, if the amount is more than 0.5 parts by mass, the progress of the foaming reaction becomes excessive, and the mechanical properties of the foam deteriorate.

  The foaming agent is for foaming polyurethane into a polyurethane foam. As the foaming agent, water or an acid amide is used. Of these foaming agents, water that is excellent in the reactivity of the foaming reaction and has good handleability is most preferable. The content of the foaming agent is preferably 2.0 to 5.0 parts by mass per 100 parts by mass of polyols in order to reduce the foaming reaction (curing reaction) from being less than usual. When the content of the foaming agent is less than 2.0 parts by mass, the foaming reaction becomes insufficient, and a sufficient communication structure of cells cannot be formed in the foam. On the other hand, when the content of the foaming agent is more than 5.0 parts by mass, the foaming reaction becomes excessive, the crosslinking density of the foam is lowered, and the mechanical strength tends to be insufficient.

  The auxiliary foaming agent is a liquefied carbon dioxide gas that is non-reactive with polyols and polyisocyanates, and is used to improve the air permeability of the foam and reduce the hardness. Unlike organic solvents such as methylene chloride, liquefied carbon dioxide gas does not dissolve in the foam, and therefore does not inhibit reactions such as the resinification reaction and allows the reaction to proceed smoothly. And it is avoided that the strength fall of a foam and the deterioration of a compression residual distortion are caused. By using liquefied carbon dioxide, the liquefied carbon dioxide vaporizes in the foam material, and stable foam is finely dispersed to form a high-viscosity soft cream (floss effect). Therefore, it is considered that the cell film is difficult to be formed. Therefore, it is presumed that the cell expands from the state by the carbon dioxide gas generated by the foaming reaction, and the cell is connected. Further, the auxiliary foaming agent has the following effects on reactions such as resinification reaction and foaming reaction.

The resinification reaction (urethane bond formation reaction) by the reaction of polyisocyanates and polyols proceeds based on the following reaction formula (1).
-R-NCO + R'OH--R-NH-CO-O-R '(1)
Moreover, the foaming reaction by reaction of polyisocyanates and water proceeds according to the following reaction formula (2).

_{-R-NCO + H 2 O →} -R-NH 2 + CO 2 ··· (2)
Furthermore, the reaction in which the amine compound (—R—NH ₂ ) produced in the reaction formula (2) reacts with polyisocyanates to form a urea (urea) bond proceeds according to the following reaction formula (3).

_{-R-NCO + -R-NH 2} → -R-NH-CO-NH-R ··· (3)
The urea bond reacts with the isocyanate group, or the urethane bond reacts with the isocyanate group, so that crosslinking (curing) proceeds.

With liquefied carbon dioxide as an auxiliary blowing agent, since the concentration of carbon dioxide (CO ₂₎ increases in the reaction formula (2), the progress of the reaction is suppressed, suppressing the generation of the amine compound (-R-NH ₂₎ It is done. Therefore, in the reaction formula (3), the reaction raw material on the left side is reduced and the progress of the reaction is restricted. The urea bond has a stronger cohesive force due to hydrogen bonds than the urethane bond, and the presence thereof increases the hardness of the foam. However, the formation of urea bonds is restricted, so that the hardness of the foam can be lowered.

  The content of the auxiliary foaming agent is 2.0 to 5.0 parts by mass per 100 parts by mass of polyols. When the content of the auxiliary foaming agent is less than 2.0 parts by mass, the effect of the auxiliary foaming agent is not sufficiently exhibited, and it becomes impossible to communicate the foam cells. On the other hand, when it exceeds 5.0 parts by mass, excessive foaming results in insufficient strength of the resin skeleton, resulting in insufficient mechanical strength of the foam. When supplying the liquefied carbon dioxide gas to the foam raw material, it is supplied after being dissolved in, for example, polyols. In that case, it is performed on the conditions which a carbon dioxide gas can hold | maintain a liquefied state at the pressure of 5-7 Mpa, and the temperature of -12-20 degreeC.

  The foam stabilizer is used as necessary in order to smoothly advance foaming performed by the foaming agent. As such a foam stabilizer, what is normally used when manufacturing a flexible polyurethane foam can be used. Specific examples of the foam stabilizer include silicone compounds, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate, polyether siloxane, and phenolic compounds. The content of the foam stabilizer is preferably 0.5 to 3.0 parts by mass per 100 parts by mass of polyols. When the content is less than 0.5 parts by mass, the foam regulating action at the time of foaming of the foam material is not sufficiently exhibited, and it becomes difficult to obtain a good foam. On the other hand, when the amount is more than 3.0 parts by mass, the foam regulating action works strongly, and the cell connectivity tends to decrease.

  In addition to the above-mentioned raw materials, flame retardants, antioxidants, ultraviolet absorbers, colorants, foam breakers (fillers) and the like can be blended in the foam raw material according to a conventional method. As the flame retardant, a halogenated phosphate ester, a condensed phosphate ester, or the like is used. As the foam breaker, diatomaceous earth, zirconium silicate, silica and the like are used.

  Next, the reaction between the polyols and the polyisocyanates is performed according to a conventional method, and a one-shot method or a prepolymer method is employed. The one-shot method is a method in which polyols and polyisocyanates are directly reacted. The prepolymer method is a method in which a part of a polyol and a polyisocyanate are reacted in advance to obtain a prepolymer having an isocyanate group or a hydroxyl group at a terminal, and the polyol or the polyisocyanate is reacted therewith. The one-shot method is a preferable method because the manufacturing process is one step compared to the prepolymer method, and there are few restrictions on the manufacturing conditions, and the manufacturing cost can be reduced.

  As the soft polyurethane foam, a soft slab polyurethane foam obtained by a slab foaming method is preferable. In the slab foaming method, the reaction raw material (reaction mixture) mixed and stirred by the one-shot method is discharged onto a belt conveyor, and while the belt conveyor moves, the reaction raw material naturally foams at room temperature and atmospheric pressure. Obtained by curing. Thereafter, it is cured (cured) in a drying furnace and cut into a predetermined shape. In addition, a flexible polyurethane foam can also be obtained by a molding method, an on-site spray molding method, or the like.

The soft polyurethane foam obtained in this way has a high air permeability of, for example, 150 to 200 L / min. Moreover, for example, the foam has a hardness of 40 to 70 N and a compressive residual strain of 1 to 2.5%, and has good mechanical properties. The apparent density of the foam is 15 to ³⁰ kg / m ³ .

  Now, the operation of the present embodiment will be described. When a flexible polyurethane foam is produced, polyols and polyisocyanates are mixed in the presence of water as a catalyst and a blowing agent, and liquefied carbon dioxide gas as an auxiliary blowing agent. It is carried out by reacting with, foaming and curing. At this time, since liquefied carbon dioxide is used as the auxiliary foaming agent, there is almost no solubility in the foam and there is no possibility of inhibiting the resinification reaction. Furthermore, when the foam raw material is mixed and discharged, the liquefied carbon dioxide gas already starts to be vaporized, so that the bubbles are stabilized and the cell film is not easily formed compared to the case of foaming from the liquid state. The amount of catalyst used can be reduced. By using this liquefied carbon dioxide gas in an appropriate amount of 2.0 to 5.0 parts by mass per 100 parts by mass of polyols, foaming can be progressed in a stable state, and the air permeability of the resulting foam is improved. be able to.

  Moreover, by using a metal catalyst for resinization as a catalyst and setting its content to a small amount of 0.05 to 0.15 parts by mass per 100 parts by mass of polyols, it is possible to suppress rupture and collapse of the foam. At the same time, the formation of the cell film can be suppressed. Furthermore, by setting the isocyanate index to 90 to 108, the foaming can proceed smoothly, and the cross-linking density can be suppressed by suppressing resinification. Combined with these actions, the air permeability and mechanical properties of the foam are expressed in a well-balanced manner.

The effects exhibited by the above embodiment will be described collectively below.
-In the manufacturing method of the flexible polyurethane foam of this embodiment, since a small amount of liquefied carbon dioxide gas is used as an auxiliary foaming agent, foaming can be advanced in a stable state, and the air permeability of the foam can be improved. In addition, since a small amount of a metal catalyst is used as the catalyst, a foam can be formed satisfactorily and the formation of a cell film can be suppressed. And by setting an isocyanate index to 90-108, foaming can be advanced smoothly, resinification can be suppressed, and a crosslinking density can be suppressed. Therefore, a foam capable of exhibiting excellent air permeability while maintaining mechanical properties can be easily produced by adjusting the raw material composition. Therefore, such a flexible polyurethane foam can be suitably used as a dust filter, an air conditioning sheet or the like that requires high air permeability.

- In addition, the catalytic constant ratio as a catalyst by using an amine catalyst is a ^{10 × 10 -1 ~40 × 10 -1} , it is possible to improve the breathability of the resulting foam.

Hereinafter, the embodiment will be described in more detail with reference to examples and comparative examples, but the invention is not limited to these examples.
(Examples 1-4 and Comparative Examples 1-8)
The raw materials of the flexible polyurethane foam containing polyols, polyisocyanates, foaming agent, auxiliary foaming agent, foam stabilizer and catalyst were prepared with the compositions shown in Tables 1 and 2. And the raw material of the flexible polyurethane foam was mixed at normal temperature, and the flexible polyurethane foam was manufactured by making it react and foam (slab foaming) according to a conventional method. The liquefied carbon dioxide gas was kept in a liquefied state at a pressure of 6 MPa and a temperature of −12 ° C. or less, and was dissolved in a polyether polyol and supplied.

  Here, Comparative Examples 1 to 3 show examples in which the liquefied carbon dioxide gas as the auxiliary foaming agent is not used and the content of the metal catalyst is excessive. Comparative Example 4 shows an example in which the isocyanate index is excessive and the content of the metal catalyst is excessive. Comparative Example 5 shows an example in which the content of the metal catalyst is excessive, and Comparative Example 6 shows an example in which the content of the metal catalyst is excessive. Comparative Example 7 shows an example in which the isocyanate index is too small and the content of the metal catalyst is excessive. Comparative Example 8 shows an example in which liquefied carbon dioxide gas as an auxiliary foaming agent is used excessively.

The meanings of the abbreviations in Table 1 and Table 2 are shown below. Moreover, content of each component represents the mass part with respect to 100 mass parts of polyols.
Polyether polyol: Polyether polyol having 3 functional groups, hydroxyl value 56.1 mgKOH / g, molecular weight 3000
Tolylene diisocyanate: A mixture of 80% by mass of 2,4-tolylene diisocyanate and 20% by mass of 2,6-tolylene diisocyanate, manufactured by Nippon Polyurethane Industry Co., Ltd., T-80
Foam stabilizer: dimethyl silicone, manufactured by Degussa, B8050
Amine catalyst 1: bis (2-dimethylaminoethyl) ether, foaming catalyst constant / gelation catalyst constant = 39.0 × 10 ⁻¹ , manufactured by GE Toshiba Silicone Co., Niax A-1
Amine catalyst 2: N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, foaming catalyst constant / gelation catalyst constant = 37.3 × 10 ⁻¹ , manufactured by Kao Corporation, KAO-3
Amine catalyst 3: N, N, N′-trimethylaminoethylethanolamine, foaming catalyst constant / gelation catalyst constant = 15.0 × 10 ⁻¹ , manufactured by Tosoh Corporation, RX5
Amine catalyst 4: Triethylenediamine, foaming catalyst constant / gelation catalyst constant = 3.8 × 10 ⁻¹ , manufactured by Kao Corporation, KAO-10
Amine catalyst 5: Mixture of triethylenediamine and propylene glycol in a mass ratio of 1: 2, manufactured by Chukyo Yushi Co., Ltd., LV33
Metal catalyst: stannous octylate, manufactured by Johoku Chemical Co., Ltd., MRH110
With respect to the obtained flexible polyurethane foam, the apparent density, hardness, compression residual strain, air flow rate and foaming behavior were measured by the following methods, and the results are also shown in Tables 1 and 2.

Apparent density (kg / m ³ ): Measured according to JIS K 7222: 1999.
Hardness (N): Measured according to JIS K 6400-2: 2004.
Compression residual strain (%): Measured according to JIS K 6400-4: 2004.

Aeration rate (L / min): Measured according to ASTM D3574.
Foaming behavior: The state of the foam raw material during foaming was visually observed, and the case where there was no puncture or collapse and foaming was performed smoothly was considered good.

表１に示したように、実施例１〜４の軟質ポリウレタン発泡体においては、補助発泡剤として液化炭酸ガス及び金属触媒を所定量用いると共に、イソシアネート指数を所定範囲に設定したことから、発泡状態は良好で、得られた発泡体は十分な通気量を示し、かつ機械的物性も良好であった。

As shown in Table 1, in the flexible polyurethane foams of Examples 1 to 4, a predetermined amount of liquefied carbon dioxide and a metal catalyst were used as auxiliary foaming agents, and the isocyanate index was set within a predetermined range, so that the foamed state The obtained foam had a sufficient air permeability and good mechanical properties.

これに対して、表２に示したように、比較例１〜３では補助発泡剤としての液化炭酸ガスを使用せず、かつ金属触媒の含有量が過剰であったため、発泡体が破裂するか、或いは発泡体の通気量が少ない結果であった。比較例４ではイソシアネート指数が過大で、かつ金属触媒の含有量が過剰であったため、架橋密度が上がって連続気泡構造が形成され難くなったものと考えられ、発泡体の通気量が少ない結果であった。比較例５では金属触媒の含有量が過剰であったため、発泡体の通気量が少ないものであった。比較例６では金属触媒の含有量が過少であり、比較例７ではイソシアネート指数が過小で、かつ金属触媒の含有量が過剰であったため、発泡のバランスが崩れて発泡体が破裂する結果であった。比較例８では、補助発泡剤としての液化炭酸ガスを過剰に使用したため、発泡体が崩壊する結果を招いた。

On the other hand, as shown in Table 2, in Comparative Examples 1 to 3, the liquefied carbon dioxide gas as the auxiliary foaming agent was not used, and the content of the metal catalyst was excessive. Or, the result was that the air permeability of the foam was small. In Comparative Example 4, since the isocyanate index was excessive and the content of the metal catalyst was excessive, it was considered that the crosslink density was increased and it was difficult to form an open cell structure. there were. In Comparative Example 5, since the content of the metal catalyst was excessive, the air permeability of the foam was small. In Comparative Example 6, the content of the metal catalyst was too low, and in Comparative Example 7, the isocyanate index was too low and the content of the metal catalyst was too high. It was. In Comparative Example 8, since the liquefied carbon dioxide gas as the auxiliary foaming agent was excessively used, the foam collapsed.

In addition, this embodiment can also be changed and embodied as follows.
-As the catalyst, a plurality of amine catalysts having different catalyst constant ratios may be used in combination to adjust the foaming reaction.

As the catalyst, a catalyst having a catalyst constant ratio outside the range of 10 × 10 ⁻¹ to 40 × 10 ⁻¹ , for example, triethylamine can be used in combination.
-In Examples 1-4, it can also comprise so that a crosslinking agent, such as polyethyleneglycol, may be mix | blended with foam raw materials and the crosslinking density of the flexible polyurethane foam obtained is adjusted.

-A soft polyurethane foam can also be used as a sound-absorbing material, a damping material, a cushioning material, etc., for example.
Further, the technical idea that can be grasped from the embodiment will be described below.

The soft polyurethane foam has an apparent density of 15 to 30 (kg / m ³ ) measured according to JIS K 7222, and an air flow rate of 150 to 200 L / min measured according to ASTM D3574. The method for producing a flexible polyurethane foam according to claim 1 or 2, wherein: In this case, in addition to the effect of the invention according to claim 1 or claim 2, the foam has a low density and can exhibit high air permeability.

  The method for producing a flexible polyurethane foam according to claim 1 or 2, wherein the flexible polyurethane foam is obtained by a slab foaming method. In this case, in addition to the effect of the invention according to claim 1 or 2, a soft polyurethane foam having an open cell structure with high air permeability can be easily obtained.

  The said polyols are polyether polyols, The manufacturing method of the flexible polyurethane foam of Claim 1 or Claim 2 characterized by the above-mentioned. In this case, in addition to the effect of the invention according to claim 1 or 2, a foam having good air permeability can be easily produced.

  The method for producing a flexible polyurethane foam according to claim 1 or 2, wherein the foaming agent is water. In this case, in addition to the effect of the invention according to claim 1 or claim 2, the handling property of the foaming agent is good, and the foaming reaction can be rapidly advanced.

  -The raw material of the said flexible polyurethane foam contains a foam stabilizer, The manufacturing method of the flexible polyurethane foam of Claim 1 or Claim 2 characterized by the above-mentioned. In this case, in addition to the effect of the invention according to claim 1 or claim 2, foaming can be smoothly advanced, and a good foam can be obtained.

  A soft polyurethane foam obtained by reacting and foaming a raw material of a flexible polyurethane foam containing a polyol, a polyisocyanate, a catalyst, a foaming agent and an auxiliary foaming agent, and liquefied carbon dioxide is used as the auxiliary foaming agent in the polyol 2.0 to 5.0 parts by mass per 100 parts by mass of a compound, a metal catalyst as a catalyst, and the content thereof is 0.05 to 0.15 parts by mass per 100 parts by mass of polyols, and A flexible polyurethane foam characterized by having an isocyanate index, expressed as a percentage, of an equivalent ratio of an isocyanate group of a polyisocyanate to an active hydrogen group of 90 to 108. In this case, the flexible polyurethane foam can exhibit excellent breathability while maintaining mechanical properties.

Claims (2)

A method for producing a flexible polyurethane foam by reacting and foaming a raw material of a flexible polyurethane foam containing a polyol, a polyisocyanate, a catalyst, a foaming agent and an auxiliary foaming agent,
As the auxiliary blowing agent, liquefied carbon dioxide is used in an amount of 2.0 to 5.0 parts by mass per 100 parts by mass of polyols, and a metal catalyst is used as a catalyst. A method for producing a flexible polyurethane foam, characterized in that the isocyanate index, which is 15 parts by mass and the equivalent ratio of the isocyanate group of the polyisocyanate to the active hydrogen group in the raw material as a percentage, is 90 to 108. 2. An amine catalyst is used as the catalyst, and the amine catalyst is a foaming catalyst having a ratio of the foaming catalyst constant to the gelation catalyst constant of 10 × 10 ⁻¹ to 40 × 10 ^−1. The manufacturing method of the flexible polyurethane foam as described in any one of.