Polyurethane foam

Abstract

To reduce the temperature dependence of polyurethane foam.SOLUTION: A polyurethane foam is obtained from a composition containing a polyol and a polyisocyanate. The polyol includes a polycarbonate polyol modified with a cyclic ester. The content of the polycarbonate polyol is 7 pts.mass or more and 35 pts.mass or less when the total amount of the polyol is 100 pts.mass.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to polyurethane foams. [Background technology]

[0002] Patent Document 1 discloses a method for producing a flexible polyurethane foam using a combination of multiple polyols with specific functional groups and OH equivalents. Patent Document 2 discloses a flexible polyurethane foam obtained by using a specific polyester polyol and a polyether polyol in combination as polyols. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-300352 [Patent Document 2] Japanese Patent Application Publication No. 10-025327 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional polyurethane foams tend to become harder in winter and softer in summer depending on the outside temperature, leaving room for improvement in terms of temperature dependency.

[0005] The present disclosure has an object to provide a polyurethane foam having low temperature dependency. The present disclosure can be realized in the following aspects. [Means for solving the problem]

[0006] A polyurethane foam obtained from a composition comprising a polyol and a polyisocyanate, The polyol contains a polycarbonate polyol modified with a cyclic ester, The polyurethane foam has a content of the polycarbonate polyol of 7 parts by mass or more and 35 parts by mass or less, relative to 100 parts by mass of the total amount of the polyols. [Effects of the Invention]

[0007] According to the present disclosure, the temperature dependency of polyurethane foam can be reduced. DETAILED DESCRIPTION OF THE INVENTION

[0008] Here, a preferred example of the present disclosure will be described. A polyurethane foam, wherein the polycarbonate polyol has a functionality of 2. A polyurethane foam, wherein the polycarbonate polyol has a hydroxyl value of 35 mgKOH / g or more and 450 mgKOH / g or less. A polyurethane foam, wherein the polycarbonate polyol has a number average molecular weight of 1,100 or more and 3,500 or less. Polyurethane foam with an Asker C hardness of 28 or less at 0°C, measured in accordance with JIS K7312. Polyurethane foam with an absolute value of the difference between the Asker C hardness at 0°C and the Asker C hardness at 23°C, measured in accordance with JIS K7312, of 20 or less. Polyurethane foam with a resilience of 45% or less at 0°C, measured in accordance with JIS K6255. A polyurethane foam in which the absolute value of the difference between the resilience modulus at 0°C and the resilience modulus at 23°C, measured in accordance with JIS K6255, is 20% or less.

[0009] The present disclosure will be described in detail below. In this specification, when a numerical range is indicated using "-", it is intended to include both the lower limit and the upper limit unless otherwise specified. For example, the expression "10-20" includes both the lower limit "10" and the upper limit "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less".

[0010] 1. Polyurethane foam The polyurethane foam is obtained from a composition containing a polyol and a polyisocyanate. The polyol contains a polycarbonate polyol modified with a cyclic ester. The content of the polycarbonate polyol is 7 parts by mass or more and 35 parts by mass or less, based on 100 parts by mass of the total amount of the polyol.

[0011] (1) Composition The composition contains a polyol and a polyisocyanate. The composition may contain at least one optional component selected from a blowing agent, a catalyst, a foam stabilizer, and a crosslinking agent. Each component of the composition will be described below.

[0012] (1.1) Polyol The polyol contains a polycarbonate polyol modified with a cyclic ester (hereinafter also referred to as a modified polycarbonate polyol). As the modified polycarbonate polyol, a polycarbonate polyol containing a structure derived from a polyol having 2 to 12 carbon atoms and a structure derived from a cyclic ester can be used.

[0013] Examples of polyols having 2 to 12 carbon atoms include ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, and dodecanediol, with butanediol, pentanediol, and hexanediol being preferred. Multiple polyols having 2 to 12 carbon atoms may be used in combination. Furthermore, to the extent that the functions and properties of the target polyurethane foam are not impaired, a polyol having 2 to 12 carbon atoms containing a small amount of ether bonds in the molecule may be used in combination, or a polyol containing a small amount of branched aliphatic polyol may be used in combination.

[0014] Examples of cyclic esters include propiolactone, butyrolactone, valerolactone, caprolactone, and laurolactone, with caprolactone being preferred. One or more cyclic esters may be used alone or in combination, and hydroxycarboxylic acids, which are hydrolyzates of cyclic esters, may also be used. The cyclic ester may contain a small amount of branched or cyclic structure or unsaturated bond, as long as the function or properties of the target polyurethane foam are not impaired.

[0015] In the modified polycarbonate polyol, the molar ratio of the structure derived from the polyol having 2 to 12 carbon atoms to the structure derived from the cyclic ester (polyol-derived structure / cyclic ester-derived structure) is preferably 10 / 90-90 / 10, more preferably 15 / 85-85 / 15, and even more preferably 20 / 80-80 / 20. The total amount of the structure derived from the polyol having 2 to 12 carbon atoms and the structure derived from the cyclic ester is preferably 95 mol % or more, more preferably 98 mol % or more, and even more preferably 99 mol % or more, based on the polycarbonate polyol.

[0016] As such a modified polycarbonate polyol, for example, a polycarbonate polyol containing repeating units of a structure derived from 1,6-hexanediol and a structure derived from caprolactone (ETERNACOLL (registered trademark) UHC, manufactured by Ube Industries, Ltd.) can be suitably used. In addition, as the modified polycarbonate polyol, carbonate polyols of the PLACCEL EC series (manufactured by Daicel Corporation) and the PLACCEL CD series (manufactured by Daicel Corporation) can also be used.

[0017] The number of functional groups, hydroxyl value, and number average molecular weight of the modified polycarbonate polyol are not particularly limited. The number of functional groups of the modified polycarbonate polyol is preferably 2. The hydroxyl value of the modified polycarbonate diol is preferably 35 mgKOH / g or more, and may be 40 mgKOH / g or more, 45 mgKOH / g or more, or 50 mgKOH / g or more. The hydroxyl value of the modified polycarbonate diol is preferably 450 mgKOH / g or less, and may be 200 mgKOH / g or less, 120 mgKOH / g or less, or 80 mgKOH / g or less. When the hydroxyl value is below the upper limit, a good foam can be obtained. When the hydroxyl value is above the lower limit, the polycarbonate diol can be easily mixed with other materials. From these viewpoints, the hydroxyl value of the modified polycarbonate diol is preferably in the range of 35 mgKOH / g or more and 450 mgKOH / g or less, and can be set to a range that appropriately combines the above upper and lower limits. The number average molecular weight of the modified polycarbonate polyol is preferably 900 or more and 4000 or less, more preferably 1100 or more and 3500 or less, and even more preferably 1500 or more and 2500 or less. The number average molecular weight of the modified polycarbonate polyol can be measured by gel permeation chromatography (GPC). When the modified polycarbonate polyol is a commercially available product, the catalog value may be used as the number average molecular weight of the modified polycarbonate polyol. In this specification, the number average molecular weight of polyols other than the modified polycarbonate polyol can be similarly defined.

[0018] The content of the modified polycarbonate polyol is 7 parts by mass or more and 35 parts by mass or less, when the total amount of polyols is 100 parts by mass. From the viewpoint of reducing temperature dependency, the content of the modified polycarbonate polyol is preferably 8 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more. From the viewpoint of moldability, the content of the modified polycarbonate polyol is preferably 33 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less. From these viewpoints, the content of the modified polycarbonate polyol is preferably 8 parts by mass or more and 33 parts by mass or less, more preferably 10 parts by mass or more and 30 parts by mass or less, and even more preferably 15 parts by mass or more and 25 parts by mass or less.

[0019] The polyol other than the modified polycarbonate polyol contained in the composition (hereinafter also referred to as "other polyol") is not particularly limited. As the other polyol, polyether polyol is preferable. Examples of polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene polypropylene glycol, etc. The other polyol can be used alone or in combination of two or more.

[0020] The number of functional groups, hydroxyl value, and number average molecular weight of the polyether polyol are not particularly limited. As the polyether polyol, a combination of a plurality of polyether polyols A and B having different numbers of functional groups, hydroxyl values, etc. may be used. The number of functional groups of polyether polyol A is preferably 3. The hydroxyl value of polyether polyol A is preferably 20 mgKOH / g or more and 100 mgKOH / g or less, more preferably 25 mgKOH / g or more and 60 mgKOH / g or less. The number average molecular weight of polyether polyol A is, for example, 4000 or more and 6000 or less. The content of polyether polyol A is, for example, 45 parts by mass or more and 93 parts by mass or less, when the total amount of polyols is 100 parts by mass. The number of functional groups of polyether polyol B is preferably 3. The hydroxyl value of polyether polyol B is preferably more than 150 mgKOH / g and 300 mgKOH / g or less, more preferably 200 mgKOH / g or more and 250 mgKOH / g or less. The number average molecular weight of polyether polyol B is, for example, 500 or more and 1000 or less. The content of polyether polyol B is, for example, 5 parts by mass or more and 25 parts by mass or less, when the total amount of polyols is 100 parts by mass.

[0021] Furthermore, polyether polyol C having two functional groups may be used in combination as the polyether polyol. The hydroxyl value of polyether polyol C is preferably 35 mgKOH / g or more and 450 mgKOH / g or less, more preferably 50 mgKOH / g or more and 80 mgKOH / g or less. The number average molecular weight of polyether polyol C is, for example, 1100 or more and 3500 or less. The content of polyether polyol C is, for example, 0 parts by mass or more and 20 parts by mass or less, when the total amount of polyols is 100 parts by mass.

[0022] (1.2) Foaming agent The blowing agent can be water, a chlorofluorocarbon substitute, or a hydrocarbon such as pentane, and can be used alone or in combination. Water is particularly preferred as the blowing agent. When water is used, carbon dioxide gas is generated during the reaction between the polyol and the polyisocyanate, and the carbon dioxide gas causes foaming. The amount of water used as the blowing agent is preferably 0.5 to 4.0 parts by mass per 100 parts by mass of the polyol.

[0023] (1.3) Catalyst The catalyst may be a single or a mixture of two or more known catalysts for polyurethane foams. Examples of the catalyst include amine catalysts such as aromatic amine catalysts and metal catalysts such as tin octoate. The total amount of catalyst is preferably 0.3 to 5.0 parts by mass per 100 parts by mass of polyol.

[0024] (1.4) Foam stabilizer The foam stabilizer may be any foam stabilizer that is commonly used as a raw material for urethane foam, such as a silicone compound, a nonionic surfactant, etc. The amount of foam stabilizer is preferably 0.2 parts by mass or more and 3.0 parts by mass or less per 100 parts by mass of polyol.

[0025] (1.5) Crosslinking agent A crosslinking agent may be blended to improve the hardness of the polyurethane foam. Examples of the crosslinking agent include amines such as diethanolamine and polyethylene polyamines, and polyhydric alcohols such as trimethylolpropane, glycerin, 1,4-butanediol, and diethylene glycol. Two or more crosslinking agents may be used. The amount of the crosslinking agent is preferably 0.3 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the polyol.

[0026] (1.6) Other ingredients Other components that may be appropriately blended into the composition include, for example, a networking agent, a flame retardant, and an antioxidant. Examples of the networking agent include polyether polyols with a high EO addition ratio, polyethylene glycol, and silicone foam stabilizers that improve breathability (have cell-breaking properties). The amount of the networking agent is preferably 0.5 parts by mass or more and 15.0 parts by mass or less per 100 parts by mass of the polyol. Examples of polyether polyols with a high EO addition ratio include polyether polyols with an EO ratio of 60 mol % or more, 70 mol % or more, and 100 mol % or less.

[0027] (1.7) Polyisocyanates The polyisocyanate is not particularly limited. As the polyisocyanate, MDI-based polyisocyanate (diphenylmethane diisocyanate-based isocyanate) is preferred. When MDI-based polyisocyanate is used, the surface of the polyurethane foam can be made softer to the touch than when, for example, TDI (toluene diisocyanate)-based polyisocyanate is used. Specific examples of MDI-based polyisocyanates include monomeric MDIs such as 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polymeric MDIs which are mixtures of diphenylmethane diisocyanate and polymethylene polyphenylene polyisocyanate, and urethane-, carbodiimide-, urea-, allophanate-, biuret-, and isocyanurate-modified versions of these polyisocyanates, as well as MDI prepolymers obtained by reacting these polyisocyanates with polyols. Multiple types of MDI-based polyisocyanates may be used in combination. Among these, the polyisocyanate preferably contains urethane-modified MDI.

[0028] The isocyanate index (INDEX) is preferably 80 or more and 120 or less, and more preferably 90 or more and 110 or less. The isocyanate index is the value obtained by dividing the number of moles of isocyanate groups in an isocyanate by the total number of moles of active hydrogen groups such as hydroxyl groups in a polyol and water used as a blowing agent, and multiplying the result by 100, and is calculated as [NCO equivalent of isocyanate / active hydrogen equivalent x 100].

[0029] (2) Physical properties of polyurethane foam The physical properties of the polyurethane foam can be appropriately set depending on the application, etc. The polyurethane foam is preferably a flexible polyurethane foam. The polyurethane foam preferably has the following physical properties:

[0030] (2.1) Asker C hardness The Asker C hardness at 0°C measured in accordance with JIS K7312 is preferably 28 or less, more preferably 25 or less, and even more preferably 23 or less, from the viewpoint of flexibility in a low-temperature environment. From the viewpoint of reducing bottoming out, the Asker C hardness at 0°C is preferably 3 or more, and more preferably 5 or more. From these viewpoints, the Asker C hardness at 0°C is preferably 3 or more and 28 or less, and more preferably 5 or more and 25 or less. The Asker C hardness at 23° C. measured in accordance with JIS K7312 is preferably 3 or more and 28 or less, and more preferably 5 or more and 25 or less. The Asker C hardness at 40° C. measured in accordance with JIS K7312 is preferably 3 or more and 28 or less, and more preferably 5 or more and 25 or less. The absolute value of the difference between the Asker C hardness at 0°C and the Asker C hardness at 23°C, measured in accordance with JIS K7312, is preferably 20 or less, and more preferably 15 or less. The absolute value of the difference between the Asker C hardness at 0°C and the Asker C hardness at 23°C is 0 or more.

[0031] (2.2) Rebound elasticity The rebound resilience at 0°C, measured in accordance with JIS K6255, is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less, from the viewpoint of low rebound properties in low-temperature environments. There are no particular restrictions on the lower limit of the rebound resilience at 0°C, but from the viewpoint of ensuring a moderate rebound force, it is preferably 20% or more, and more preferably 25% or more. From these viewpoints, the rebound resilience at 0°C is preferably 20% or more and 50% or less, and more preferably 25% or more and 45% or less. The rebound resilience at 23° C. measured in accordance with JIS K6255 is preferably 20% or more and 50% or less, and more preferably 25% or more and 45% or less. The rebound resilience at 40° C. measured in accordance with JIS K6255 is preferably 20% or more and 50% or less, and more preferably 25% or more and 45% or less. The absolute value of the difference between the rebound resilience at 0°C and the rebound resilience at 23°C, measured in accordance with JIS K6255, is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less. The absolute value of the difference between the rebound resilience at 0°C and the rebound resilience at 23°C is 0% or more.

[0032] (2.3) Apparent core density, tensile strength, elongation, tear strength Apparent core density (JIS K7222) is 80 kg / m 3 More than 300kg / m 3 The following is preferred: The tensile strength (JIS K6400-55) is preferably 80 kPa or more, more preferably 150 kPa or more, and even more preferably 300 kPa or more. The upper limit of the tensile strength is not particularly limited, but may be, for example, 500 kPa or less. The elongation (JIS K6400-5 5) is preferably 50% or more and 500% or less, and more preferably 100% or more and 200% or less. The tear strength (JIS K6400-5 6 B method) is more preferably 10 N / cm or more. The upper limit of the tear strength is not particularly limited, but may be, for example, 25 N / cm or less.

[0033] 2. Polyurethane foam manufacturing method The polyurethane foam can be produced by a known foaming method in which the composition is stirred and mixed to react the polyol and polyisocyanate. The foaming method includes slab foaming and mold foaming, and either molding method may be used. Mold foaming is a method in which a mixed polyurethane resin composition is filled into a mold (forming tool) and foamed within the mold. Mold foaming is suitable for molding products with complex three-dimensional shapes.

[0034] 3. Uses of polyurethane foam According to the present disclosure, a low-resilience polyurethane foam with reduced temperature dependence can be realized. The reason for the reduced temperature dependence is presumably because the incorporation of a specified proportion of modified polycarbonate polyol lowers the glass transition temperature of the polyurethane foam compared to a polyurethane foam without the incorporation of modified polycarbonate polyol. Such polyurethane foam is suitable for use in components that support at least part of the human body, where changes in hardness and rebound resilience are likely to affect performance and usability.

[0035] There is no limitation on the articles in which the polyurethane foam of the present disclosure can be used, but the polyurethane foam is suitable for supports for joints such as elbows and knees, cushions, automobile headrests, armrests, motorcycle saddles, etc. [Example]

[0036] The present invention will be specifically described below with reference to examples. In Tables 1 and 2, when an "*" is added, such as "Experimental Example 1*," it indicates that the example is a comparative example. Experimental Examples 6-8 are examples, and Experimental Examples 1-5 and 9-11 are comparative examples. 1. Polyurethane foam manufacturing Compositions were prepared according to the proportions shown in Tables 1 and 2, and polyurethane foams of the examples and comparative examples were produced by mold foaming.

[0037] The details of each raw material are as follows: Polyether polyol A: Polyether polyol, polypropylene oxide (VORANOL 4701, manufactured by Dow Chemical Japan Co., Ltd.) having ethylene oxide at the end, hydroxyl value 35 mg KOH / g, functionality 3, number average molecular weight 5000 Polyether polyol B: Polyether polyol, polypropylene glycol (GP750NS, manufactured by Sanyo Chemical Industries, Ltd.), hydroxyl value 225 mg KOH / g, number of functional groups 3, number average molecular weight 750, EO ratio 0 mol% Polyether polyol C: Polyether polyol (D2000, manufactured by Asahi Glass Co., Ltd.), hydroxyl value 56 mg KOH / g, number of functional groups 2, number average molecular weight 2000, EO ratio 0 mol% Modified polycarbonate polyol: Polycarbonate diol containing repeating units derived from 1,6-hexanediol and caprolactone (ETERNACOLL UHC50-200, manufactured by Ube Industries, Ltd.), 56 mg KOH / g, functionality 2, number average molecular weight 2000 Polycarbonate polyol: Polycarbonate diol containing repeating units derived from 1,6-hexanediol and 1,5-pentanediol (ETERNACOLL PH-200, manufactured by Ube Industries, Ltd.), 56 mg KOH / g, functionality 2, number average molecular weight 2000 - Opening agent: Polyether polyol with a high EO addition ratio (VORANOL CP1421, manufactured by Dow Chemical Japan Co., Ltd.), functionality 3, hydroxyl value 35 mg KOH / g, molecular weight 5000, EO ratio 70 mol% Crosslinker: Diethanolamine Catalyst 1: Amine catalyst (terminal amine reactive resinification catalyst) Catalyst 2: Aromatic amine catalyst Foam stabilizer: Silicone foam stabilizer Foaming agent: Water Polyisocyanate: Urethane-modified MDI (Lupranate MP-102, manufactured by BASF INOAC)

[0038] 2. Evaluation Method Test pieces were cut out from the polyurethane foams produced using the above raw materials, and the Asker C hardness, rebound resilience, etc. were measured by the following methods. Experimental Examples 10 and 11 were not evaluated for physical properties due to poor molding. (1) Asker C hardness The Asker C hardness was measured in accordance with JIS K7312. The test temperatures were 0°C, 23°C, and 40°C. The test pieces were left to stand at the test temperature conditions for 24 hours or more before measurement. (2) Rebound elasticity The rebound resilience (%) was measured in accordance with JIS K6255. The test temperatures were 0° C., 23° C., and 40° C. The test pieces were left to stand at the test temperature conditions for 24 hours or more before measurement. (3) Apparent core density, tensile strength, elongation, tear strength The apparent core density was measured in accordance with JIS K7222. The tensile strength (kPa) was measured in accordance with JIS K6400-55. The elongation (%) was measured in accordance with JIS K6400-55. The tear strength (N / cm) was measured in accordance with JIS K6400-5 6 B method.

[0039] [Table 1]

[0040] [Table 2]

[0041] 3.Results The results are shown in Tables 1 and 2. In Tables 1 and 2, "-" indicates that no measurement was performed. The column "Asker C hardness, 0°C: H1" shows the Asker C hardness at 0°C. The column "Asker C hardness, 23°C: H2" shows the Asker C hardness at 23°C. The column "Asker C hardness, 40°C" shows the Asker C hardness at 40°C. The column "Difference between Asker C hardness at 0°C and 23°C: |H1-H2|" shows the absolute value of the difference between the Asker C hardness at 0°C and the Asker C hardness at 23°C. The column "Rebound resilience (%), 0°C: R1" shows the rebound resilience at 0°C. The column "Rebound resilience (%), 23°C: R2" shows the rebound resilience at 23°C. The column "Rebound resilience (%), 40°C" shows the rebound resilience at 40°C. The column "Rebound resilience (%), difference between 0°C and 23°C: |R1-R2|" shows the absolute value of the difference between the rebound resilience at 0°C and the rebound resilience at 23°C.

[0042] In Experimental Examples 6-8, the Asker C hardness measured under conditions of 0°C, 23°C, and 40°C was 5 or more and 28 or less. Experimental Examples 6-8 had practical Asker C hardness. Furthermore, in Experimental Examples 6-8, the difference between the Asker C hardness at 0°C and the Asker C hardness at 23°C was 20 or less. It was confirmed that Experimental Examples 6-8 had little temperature dependency.

[0043] In Experimental Examples 6-8, the rebound resilience measured at 0°C, 23°C, and 40°C was 40% or less. Experimental Examples 6-8 had a practically acceptable rebound resilience. Furthermore, in Experimental Examples 6-8, the difference between the rebound resilience at 0°C and the rebound resilience at 23°C was 20% or less. It was confirmed that Experimental Examples 6-8 had little temperature dependency.

[0044] 4. Effects of the Example According to the above examples, the temperature dependency of polyurethane foam can be reduced.

[0045] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the present disclosure.

Claims

1. A polyurethane foam obtained from a composition comprising a polyol and a polyisocyanate, The polyol contains a polycarbonate polyol modified with a cyclic ester, the content of the polycarbonate polyol is 7 parts by mass or more and 35 parts by mass or less, when the total amount of the polyol is 100 parts by mass, A polyurethane foam that satisfies the following (1) and / or (2): (1) Tensile strength (JIS K6400-5 5) is 500 kPa or less (2) Tear strength (JIS K6400-5 6 B method) is 25 N / cm or less

2. The polyurethane foam according to claim 1, having an apparent core density (JIS K7222) of 80 kg / m 3 or more and 300 kg / m 3 or less.

3. A polyurethane foam as described in claim 1 or claim 2, having an Asker C hardness of 28 or less at 0°C measured in accordance with JIS K7312.

4. A polyurethane foam obtained from a composition comprising a polyol and a polyisocyanate, the polyol contains a polycarbonate polyol modified with a cyclic ester and a polyether polyol having a hydroxyl value of 20 mgKOH / g or more and 100 mgKOH / g or less, the content of the polycarbonate polyol is 7 parts by mass or more and 35 parts by mass or less, when the total amount of the polyol is 100 parts by mass, The polyurethane foam has a content of the polyether polyol of 45 parts by mass or more and 93 parts by mass or less, relative to 100 parts by mass of the total amount of the polyols.

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