Flexible polyurethane foam

Abstract

To provide a flexible polyurethane foam capable of achieving both impact resilience and elongation, and capable of obtaining from a composition containing plant-derived polyols.SOLUTION: A flexible polyurethane foam is obtained from a composition containing polyols, including plant-derived polyols and petroleum-derived polyols, and isocyanates. The flexible polyurethane foam has an elongation of 180% or more in accordance with JIS K6400-5:2012, a resilience of 30% or more in accordance with JIS K6400-3:2011, and a tear strength of 4.0 N / cm or more according to Method B of JIS K6400-5:2012. The plant-derived polyol includes a first polyol having primary hydroxyl groups.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a flexible polyurethane foam obtained from a composition containing a plant-derived polyol.

Background Art

[0002] In order to reduce the environmental impact of flexible polyurethane foams, prior art using compositions containing plant-derived polyols is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to Patent Document 1, the flexible polyurethane foam according to Examples 1-19 obtained from a composition containing a plant-derived polyol has an average resilience of about 32% in accordance with JIS K6400-3, but since the average elongation in accordance with JIS K6400-5 is about 90%, there is room for improvement.

[0005] The present invention has been made to solve this problem, and an object thereof is to provide a flexible polyurethane foam obtained from a composition containing a plant-derived polyol that can achieve both resilience and elongation.

Means for Solving the Problems

[0006] To achieve this objective, a first aspect of the present invention provides a flexible polyurethane foam obtained from a composition comprising a polyol containing a plant-derived polyol and a petroleum-derived polyol, and an isocyanate, wherein the plant-derived polyol includes a first polyol having a primary hydroxyl group. For example, the polyol consists of a first polyol and a petroleum-derived polyol, with 40-80 parts by mass of the first polyol and 20-60 parts by mass of the petroleum-derived polyol in 100 parts by mass of the polyol.

[0007] The second embodiment is the first embodiment, wherein the hydroxyl value of the first polyol is less than 60 mgKOH / g.

[0008] In the third embodiment, the biomass content of the flexible polyurethane foam is 25% or more, as in the first or second embodiment.

[0009] The fourth aspect is that, in any of the first to third aspects, the plant-derived polyol includes a second polyol having a secondary hydroxyl group, and the proportion of the mass of the plant-derived polyol to the mass of the polyol is 40% or more.

[0010] The fifth aspect is that, in any of the first to fourth aspects, the polyol includes a petroleum-derived polyol, and the proportion of the mass of the plant-derived polyol to the total mass of the polyol is 40% or more.

[0011] The sixth aspect is that, in the first or second aspect, the plant-derived polyol consists of the first polyol, and the biomass content of the flexible polyurethane foam is 30% or more.

[0012] The seventh aspect is that, in any of the first to sixth aspects, the rebound elasticity of the flexible polyurethane foam in accordance with JIS K6400-3:2011 is 20% or more.

[0013] The eighth aspect is that in any of the first to seventh aspects, the elongation of the flexible polyurethane foam in accordance with JIS K6400-5:2012 is 100% or more.

[0014] The ninth aspect is that, in any of the first to eighth aspects, the tear strength of the flexible polyurethane foam, in accordance with Method B of JIS K6400-5:2012, is 4.0 N / cm or more. [Effects of the Invention]

[0015] According to the present invention, the first polyol, which is a plant-derived polyol, contains a hydroxyl group (primary hydroxyl group) in which one carbon atom is bonded to the carbon atom to which the hydroxyl group is bonded. Since the primary hydroxyl group has only one hydrocarbon group bonded to the carbon atom to which the hydroxyl group is bonded, it has low steric hindrance, and therefore the first polyol has high reactivity in resin formation with isocyanates. As a result, it is possible to achieve both rebound elasticity and elongation in a flexible polyurethane foam. [Modes for carrying out the invention]

[0016] Preferred embodiments of the present invention will be described below. The flexible polyurethane foam is obtained from a composition comprising a polyol containing a plant-derived polyol and an isocyanate. A polyol is a compound having two or more hydroxyl groups in one molecule. Examples of plant-derived polyols include polyols made from plant-derived oils and fats. Examples of plant-derived oils and fats include castor oil, sunflower oil, rapeseed oil, linseed oil, cottonseed oil, tuna oil, coconut oil, poppy oil, corn oil, and soybean oil.

[0017] Plant-derived polyols include a primary polyol having a primary hydroxyl group. This primary polyol has only one hydrocarbon group bonded to the carbon atom to which the hydroxyl group is attached, resulting in low steric hindrance and thus improving the reactivity of the polyol.

[0018] The first polyol preferably has a functional group count of 2.0 or more and less than 3.5, and a hydroxyl value of less than 60 mgKOH / g. This is because it is possible to form a crosslinked structure with an appropriate crosslink density and number of crosslinking points, thereby improving the mechanical properties such as rebound elasticity of the flexible polyurethane foam obtained from the composition containing the first polyol.

[0019] The first polyol may be contained in a range of 10 wt% or more and 100 wt% or less based on the mass of the polyol in the composition. This is to ensure the reactivity of the plant-derived polyol.

[0020] Preferably, the plant-derived polyol consists of the first polyol (all of the plant-derived polyol is the first polyol), but it may also contain a second polyol. The second polyol contains a hydroxy group (secondary hydroxy group) to which two carbon atoms are bonded to the carbon atom to which the hydroxy group is bonded. Since the second polyol has two hydrocarbon groups bonded to the carbon atom to which the hydroxy group is bonded and has a large steric hindrance, the reactivity of the polyol decreases, but it can supplement the plant-derived material. The analysis of primary and secondary hydroxy groups can be performed by carbon-13 nuclear magnetic resonance spectrum.

[0021] When the plant-derived polyol contains the second polyol, the proportion of the mass of the plant-derived polyol in the mass of the polyol in the composition is preferably 40% or more. This is to ensure the biomass degree of the flexible polyurethane foam.

[0022] The biomass degree can be determined using the following formula (1). Biomass degree = mass of plant-derived polyol × biomass degree of each polyol / (total mass of all raw materials constituting the composition - mass reduction due to gasification) ··· Formula (1)

[0023] The "mass reduction due to gasification" in formula (1) is a value obtained by multiplying the value obtained by dividing the mass of water contained in the raw material by the molecular weight of water (18) by the molecular weight of carbon dioxide (44).

[0024] The biomass degree of the flexible polyurethane foam is preferably 25% or more. This is to reduce the environmental load of the flexible polyurethane foam.

[0025] When the plant-derived polyol consists of the first polyol, the biomass content of the flexible polyurethane foam is preferably 30% or more. This is to further reduce the environmental impact of the flexible polyurethane foam.

[0026] In addition to the plant-derived polyol, the polyol may contain a petroleum-derived polyol. Since the reactivity of the petroleum-derived polyol is intermediate between the reactivity of the first polyol and the reactivity of the second polyol, it has the effect of widening the appropriate range of the catalyst amount and contributes to the improvement of the moldability. When the polyol contains a petroleum-derived polyol, the proportion of the mass of the plant-derived polyol in the mass of the polyol in the composition is preferably 40% or more. This is to ensure the biomass content of the flexible polyurethane foam.

[0027] Examples of the petroleum-derived polyol include polyether polyol, polymer polyol, polyester polyol, etc. Examples of the polyether polyol include polyether polyols obtained by adding alkylene oxides such as ethylene oxide (EO) and propylene oxide (PO) to polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose.

[0028] The polyether polyol is preferably a polyether polyol having a weight average molecular weight of 500 - 12500 (preferably 800 - 6000, more preferably 1000 - 3000) and a functionality of 2 - 6 (preferably 2 or 3).

[0029] Polymer polyols include those obtained by graft copolymerizing vinyl monomers such as acrylonitrile and styrene in a polyether polyol having 2 or 3 functional groups as a base polyol. Examples of base polyols include polyether polyols containing PO units (propylene oxide units) and EO units (ethylene oxide units) as AO units (alkylene oxide units). The number-average molecular weight of the polymer polyol can be determined by the number-average molecular weight measured by gel permeation chromatography (GPC).

[0030] Examples of polyester polyols include polycaprolactone-based polyester polyols and adipate-based polyester polyols. Examples of polycaprolactone-based polyester polyols include those obtained by ring-opening addition polymerization of lactones such as ε-caprolactone. Examples of adipate-based polyester polyols include those obtained by polycondensation of a polyfunctional carboxylic acid and a polyfunctional hydroxy compound.

[0031] When low molecular weight polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol are used, these polyhydric alcohols are also included in the category of polyols.

[0032] Isocyanates are compounds having multiple isocyanate groups, and examples include aromatic isocyanates such as toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate, and xylylene diisocyanate (XDI); alicyclic isocyanates such as isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate (HDI); or modified isocyanates such as free isocyanate prepolymers obtained by reaction of these with polyols, and carbodiimide-modified isocyanates. One or more of these isocyanates are used.

[0033] The index is the equivalent ratio of the isocyanate groups of the isocyanate to the functional groups, such as hydroxyl groups, of the polyol that can react with the isocyanate. From the viewpoint of reaction stability, the index should be 91 or higher, preferably 93 or higher, more preferably 95 or higher, and from the viewpoint of reducing exothermic reaction during foaming, it should be 125 or lower, preferably 115 or lower, and more preferably 110 or lower.

[0034] The composition preferably contains a catalyst, a foam stabilizer, and a foaming agent. The catalyst mainly promotes the resinification reaction between the polyol and the isocyanate. Examples of catalysts include tertiary amines such as triethylenediamine, N,N-dimethylaminoethanol, 6-dimethylamino-1-hexanol, and N,N',N'-trimethylaminoethylpiperazine, organometallic compounds such as stanus octoate and stannous octoate, acetates, and alkali metal alcohols. There are no particular restrictions on the proportion of catalyst in the composition, but it is preferably 0.1 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of polyol. This is to promote the resinification reaction and reduce the non-uniformity of the cell structure.

[0035] Examples of foam stabilizers include organopolysiloxanes, organopolysiloxane-polyoxyalkylene copolymers, polyalkenylsiloxanes having polyoxyalkylene side chains, silicone compounds such as silicone-grease copolymers, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate, polyethersiloxanes, and phenolic compounds. There are no particular restrictions on the proportion of foam stabilizers in the composition, but it is preferably 0.03 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of polyol.

[0036] Examples of blowing agents include water, carbon dioxide, and hydrohaloolefins. When water is used as the blowing agent, the proportion of the blowing agent in the composition is preferably 1 to 10 parts by mass per 100 parts by mass of polyol.

[0037] The composition may contain additives. Examples of additives include antioxidants, UV absorbers, thickeners, plasticizers, flame retardants, antibacterial agents, and colorants. Examples of antioxidants include dibutylhydroxytoluene and hindered phenol antioxidants. Examples of thickeners include calcium carbonate, aluminum hydroxide, and magnesium hydroxide.

[0038] Flexible polyurethane foam can be produced by known foaming methods that involve stirring and mixing a composition to react a polyol with an isocyanate. These foaming methods include slab foaming and mold foaming. Slab foaming involves extruding the mixed composition onto a belt conveyor and foaming it at atmospheric pressure and room temperature. Mold foaming involves filling a mold with the mixed composition and foaming it within the mold.

[0039] Applications of flexible polyurethane foam include bedding, chair cushions and backrests, sofas, cushioning materials, sound-absorbing materials, building materials, cleaning sponges, and hydroponic growing media. Examples of bedding applications include mattresses, comforters, futons, and pillows.

[0040] The rebound elasticity of flexible polyurethane foam conforming to JIS K6400-3:2011 should be 20% or more, preferably 30% or more. The rebound elasticity is typically 90% or less.

[0041] The elongation of the flexible polyurethane foam conforming to JIS K6400-5:2012 (test specimen type 2) should be 100% or more, preferably 130% or more. The elongation is typically 500% or less.

[0042] The tear strength of flexible polyurethane foam conforming to Method B of JIS K6400-5:2012 is preferably 4.0 N / cm or higher. The tear strength is usually 10 N / cm or less. [Examples]

[0043] The present invention will be described in more detail by reference to examples, but the present invention is not limited to these examples. Table 1 shows the raw material formulations for flexible polyurethane foam in Examples 1-16. Table 2 shows the raw material formulations for flexible polyurethane foam in Examples 17-25 and Comparative Examples 1-5. The values ​​shown in Tables 1 and 2 (excluding the index) are the unit mass when the polyol (first polyol, second polyol, and petroleum-derived polyol) is 100 parts by weight.

[0044] [Table 1]

[0045] [Table 2]

[0046] The raw materials shown in Tables 1 and 2 are as follows:

[0047] Polyol 1 (first type): Derived from castor oil, biomass content 95.7%, hydroxyl value 56 mgKOH / g, average molecular weight 3000, number of functional groups 3.0, all hydroxyl groups are primary hydroxyl groups. Polyol 1 2: Corn-derived, 100% biomass content, hydroxyl value 56 mgKOH / g, average molecular weight 2000, number of functional groups 2.0, all hydroxyl groups are primary hydroxyl groups Polyol 3 (1st generation): Corn-derived, 100% biomass content, hydroxyl value 187 mgKOH / g, average molecular weight 600, number of functional groups 2.0, all hydroxyl groups are primary hydroxyl groups. Second polyol 1: Derived from castor oil, biomass content 93%, hydroxyl value 153 mgKOH / g, average molecular weight 990, number of functional groups 2.7, all hydroxyl groups are secondary hydroxyl groups. Second polyol 2: Derived from castor oil, 100% biomass content, hydroxyl value 90 mgKOH / g, average molecular weight 2182, number of functional groups 3.5, all hydroxyl groups are secondary hydroxyl groups. Petroleum-derived polyol 1: Hydroxyl value 51 mgKOH / g, average molecular weight 3300, number of functional groups 3 Petroleum-derived polyol 2: Hydroxyl value 56 mgKOH / g, average molecular weight 3000, number of functional groups 3 Petroleum-derived polyol 3: Hydroxyl value 45 mgKOH / g, average molecular weight 3740, number of functional groups 3 Petroleum-derived polyol 4: Hydroxyl value 112 mgKOH / g, average molecular weight 1000, number of functional groups 2 Petroleum-derived polyol 5: Hydroxyl value 56 mgKOH / g, average molecular weight 2000, number of functional groups 2 Isocyanates: Toluene diisocyanate (TDI), 2,4-toluene diisocyanate 75-85%, 2,6-toluene diisocyanate 15-25% Catalyst 1: Amine-based catalyst, DABCO(registered trademark) 33LX Catalyst 2: Amine-based catalyst, TEDA(registered trademark) L33 Catalyst 3: Amine-based catalyst, DABCO(registered trademark) BL-22 Catalyst 4: Amine-based catalyst, DABCO(registered trademark) NE300 Catalyst 5: Metal catalyst, KOSMOS® T9 Catalyst 6: Metal catalyst, Neostan (registered trademark) U-28 Foam stabilizer 1: VORASURF (registered trademark) SF2904 Foam stabilizer 2: TEGOSTAB (registered trademark) B8244 Foam stabilizer 3: TEGOSTAB (registered trademark) B8228 Connecting agent: Actcall (registered trademark) EP-505S Foaming agent: Water

[0048] The average molecular weight of the first polyol 1-3, the second polyol 1,2, and petroleum-derived polyol 1-5 is calculated by multiplying the molecular weight of KOH by the number of functional groups in the polyol, multiplying that value by 1000, dividing that value by the hydroxyl value of the polyol, and rounding the quotient to the first decimal place.

[0049] Actcol® EP-505S is a polyether polyol (a random copolymer of propylene oxide and ethylene oxide containing 70-75 wt% ethylene oxide), and therefore can be considered a type of petroleum-derived polyol. However, because it was used as a bonding agent, it is not included in the category of polyols.

[0050] Compositions were prepared by blending the raw materials as shown in Tables 1 and 2, and flexible polyurethane foams for Examples 1-25 and Comparative Examples 1-5 were produced by slab foaming. The biomass content of the flexible polyurethane foam was calculated using formula (1) above. Density was determined by the method in accordance with JIS K7222:2005. 40% hardness was determined by the method in accordance with JIS K6400-2:2012 Method A. Air permeability was determined by the method in accordance with JIS K6400-7:2012 Method B. Rebound elasticity was determined by the method in accordance with JIS K6400-3:2011. Tensile strength and elongation were determined by the method in accordance with JIS K6400-5:2012 (test specimen type 2). Tear strength was determined by the method in accordance with JIS K6400-5:2012 Method B. The 75% compressive residual strain was determined by a method compliant with JIS K6400-4:2004 Method A.

[0051] As shown in Tables 1 and 2, Examples 1-6 contained 40 parts by mass of the first polyol and 60 parts by mass of petroleum-based polyol out of 100 parts by mass of polyol. The biomass content was 25% or more and less than 30%, the rebound elasticity was 20% or more (especially 30% or more), the elongation was 100% or more (especially 170% or more), the tear strength was 4.0 N / cm or more (especially 5.0 N / cm or more), and the 75% compression residual strain was less than 5% (especially less than 3.0%).

[0052] Examples 7-9 contain 10-30 parts by mass of a first polyol, 10-30 parts by mass of a second polyol, and 60 parts by mass of a petroleum-based polyol, out of 100 parts by mass of polyol. The biomass content was 25% or more and less than 30%, the rebound elasticity was 20% or more (especially 30% or more), the elongation was 100% or more (especially 150% or more), the tear strength was 4.0 N / cm or more, and the 75% compression residual strain was less than 5% (especially less than 3.5%).

[0053] Examples 10-14 contained 45-80 parts by mass of the first polyol and 20-55 parts by mass of petroleum-based polyol out of 100 parts by mass of polyol. The biomass content was 30% or more and less than 60%, the rebound elasticity was 20% or more (especially 30% or more), the elongation was 100% or more (especially 180% or more), the tear strength was 4.0 N / cm or more (especially 6.0 N / cm or more), and the 75% compression residual strain was less than 5% (especially less than 3.5%).

[0054] Examples 15 and 16 contain 100 parts by mass of the first polyol out of 100 parts by mass of polyol. The biomass content was 60% or more and less than 70%, the rebound elasticity was 20% or more (especially 30% or more), the elongation was 100% or more (especially 140% or more), the tear strength was 4.0 N / cm or more (especially 5.0 N / cm or more), and the 75% compression residual strain was less than 5% (especially 4.0% or less).

[0055] Examples 17 and 18 contained 50-60 parts by mass of the first polyol, 20% by mass of the second polyol, and 20-30 parts by mass of petroleum-based polyol out of 100 parts by mass of polyol. The biomass content was 40% or more and less than 60%, the rebound elasticity was 20% or more (especially 30% or more), the elongation was 100% or more (especially 160% or more), the tear strength was 4.0 N / cm or more (especially 5.0 N / cm or more), and the 75% compression residual strain was less than 6%.

[0056] Examples 19 and 20 contained 60-80 parts by mass of the first polyol and 20-40% by mass of the second polyol out of 100 parts by mass of polyol. The biomass content was 60% or more and less than 70%, the rebound elasticity was 20% or more and less than 30%, the elongation was 100% or more, the tear strength was 4.0 N / cm or more and 5.0 N / cm or less, and the 75% compression residual strain was less than 5%.

[0057] Examples 21-25 contained 70-80 parts by mass of a first polyol, 10-30% by mass of a second polyol, and 0-10 parts by mass of a petroleum-based polyol, out of 100 parts by mass of polyol. The biomass content was 60% or more and less than 75%, the rebound elasticity was 20% or more (especially 25% or more), the elongation was 125% or more, the tear strength was 4.0 N / cm or more, and the 75% compression residual strain was less than 5%.

[0058] Comparative Example 1 contains 100 parts by mass of petroleum-based polyol out of 100 parts by mass of polyol. Its biomass content was 0%, its rebound elasticity was 46%, its elongation was 148%, its tear strength was 4.7 N / cm, and its 75% compression residual strain was 1.6%. Comparative Examples 2-5 contain 30-100% by mass of a second polyol and 0-70 parts by mass of petroleum-based polyol out of 100 parts by mass of polyol in order to increase the biomass content.

[0059] In Comparative Examples 2-5, the proportion of the second polyol and the proportion of the petroleum-based polyol increased as the comparative example number increased. As the proportion of the second polyol increased, the biomass content increased, but the rebound elasticity, elongation, and tear strength decreased. However, when the proportion of the second polyol reached 100% (Comparative Example 5), the elongation and tear strength were comparable to Comparative Example 1, where the proportion of petroleum-based polyol was 100%. However, the rebound elasticity continued to decrease as the proportion of the second polyol increased, with the rebound elasticity of Comparative Example 4 being less than 30% and the rebound elasticity of Comparative Example 5 being less than 20%.

[0060] In contrast, Examples 1-25 had a biomass content of 25% or more, rebound elasticity of 20% or more, elongation of 100% or more, and tear strength of 4.0 N / cm or more. According to the examples, it was revealed that a flexible polyurethane foam with a biomass content of 25% or more, rebound elasticity of 20% or more, elongation of 100% or more, and tear strength of 4.0 N / cm or more can be obtained from a composition containing a plant-derived polyol having a primary hydroxyl group (first polyol).

[0061] Although the present invention has been described above based on embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention.

Claims

1. A flexible polyurethane foam obtained from a composition containing a polyol and an isocyanate, including plant-derived polyols and petroleum-derived polyols, The plant-derived polyol comprises a first polyol having a primary hydroxyl group, The first polyol mentioned above includes a polyol derived from castor oil in which all hydroxyl groups are primary hydroxyl groups. The elongation according to JIS K6400-5:2012 is 180% or more. The rebound elasticity in accordance with JIS K6400-3:2011 is 30% or more. A flexible polyurethane foam with a tear strength of 4.0 N / cm or higher, in accordance with Method B of JIS K6400-5:2012.

2. The flexible polyurethane foam according to claim 1, wherein the polyol comprises the first polyol and the petroleum-derived polyol.

3. The flexible polyurethane foam according to claim 2, comprising 40-80 parts by mass of the first polyol and 20-60 parts by mass of the petroleum-derived polyol out of 100 parts by mass of the polyol.

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