Soft polyurethane foam

Abstract

To provide a flexible polyurethane foam that can achieve both impact resilience and elongation and is obtained from a composition containing a plant-derived polyol. [Solution] The flexible polyurethane foam is obtained from a composition containing a polyol including a plant-derived polyol and an isocyanate, and the plant-derived polyol contains a first polyol having a primary hydroxyl group. The first polyol preferably has a hydroxyl group value of less than 60 mgKOH / g, and the flexible polyurethane foam preferably has a biomass degree of 25% or more. The plant-derived polyol may contain a second polyol having a secondary hydroxyl group, and in that case, the proportion of the mass of the plant-derived polyol in the mass of the polyol is 40% or more.

Description

[Technical field]

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

[0002] A prior art technique using a composition containing a plant-derived polyol to reduce the environmental impact of flexible polyurethane foam is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2024-2578 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to Patent Document 1, the flexible polyurethane foams of Examples 1-19 obtained from compositions containing plant-derived polyols have an average rebound resilience of about 32% in accordance with JIS K6400-3, but an average elongation of about 90% in accordance with JIS K6400-5, leaving room for improvement.

[0005] The present invention has been made to solve these problems, and has an object to provide a flexible polyurethane foam that is obtainable from a composition containing a plant-derived polyol and that is capable of achieving both rebound resilience and elongation. [Means for solving the problem]

[0006] To achieve this object, a first aspect of the present invention is a flexible polyurethane foam obtained from a composition comprising a polyol and an isocyanate, the polyol comprising a plant-derived polyol, the plant-derived polyol comprising a first polyol having a primary hydroxyl group.

[0007] In a second embodiment, in the first embodiment, the first polyol has a hydroxyl value of less than 60 mg KOH / g.

[0008] In a third aspect, in the first or second aspect, the flexible polyurethane foam has a biomass degree of 25% or more.

[0009] In a fourth aspect, in any one 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 in the mass of the polyol is 40% or more.

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

[0011] In a sixth aspect, in the first or second aspect, the plant-derived polyol comprises the first polyol, and the biomass degree of the flexible polyurethane foam is 30% or more.

[0012] In a seventh aspect, in any one of the first to sixth aspects, the flexible polyurethane foam has a rebound resilience of 20% or more in accordance with JIS K6400-3:2011.

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

[0014] In a ninth aspect, in any one of the first to eighth aspects, the flexible polyurethane foam has a tear strength of 4.0 N / cm or more in accordance with JIS K6400-5:2012, Method B. Effect 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 a carbon atom to which a hydroxyl group is bonded. The primary hydroxyl group has only one hydrocarbon group bonded to the carbon atom to which the hydroxyl group is bonded, and the steric hindrance is small, so the first polyol has high reactivity with isocyanate to form a resin. Therefore, the flexible polyurethane foam can have both high resilience and high elongation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A preferred embodiment of the present invention will be described below. A flexible polyurethane foam is obtained from a composition containing a polyol including 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, tung oil, coconut oil, poppy seed oil, corn oil, and soybean oil.

[0017] The plant-derived polyol includes a first polyol having a primary hydroxyl group. The first polyol has only one hydrocarbon group bonded to the carbon atom to which the hydroxyl group is bonded, and therefore has little steric hindrance, which can improve the reactivity of the polyol.

[0018] The first polyol preferably has a functionality of 2.0 or more and less than 3.5 and a hydroxyl value of less than 60 mgKOH / g, because it can form a crosslinked structure having an appropriate crosslink density and number of crosslinking branch points, and the mechanical properties such as impact resilience of a flexible polyurethane foam obtained from a composition containing the first polyol are improved.

[0019] The first polyol may be contained in the composition in an amount of 10 wt % or more and 100 wt % or less based on the mass of the polyol in the composition, in order to ensure the reactivity of the plant-derived polyol.

[0020] The plant-derived polyol is preferably composed of a first polyol (all plant-derived polyols are the first polyol), but may also contain a second polyol. The second polyol contains a hydroxyl group (secondary hydroxyl group) with two carbon atoms bonded to a carbon atom to which a hydroxyl group is bonded. The second polyol has two hydrocarbon groups bonded to the carbon atom to which a hydroxyl group is bonded, and the reactivity of the polyol is reduced due to the large steric hindrance, but it can supplement the plant-derived material. Primary and secondary hydroxyl groups can be analyzed by carbon-13 nuclear magnetic resonance spectroscopy.

[0021] When the plant-derived polyol contains a 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, in order to ensure the biomass degree of the flexible polyurethane foam.

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

[0023] The “mass loss due to gasification” in equation (1) is the mass of water contained in the raw material divided by the molecular weight of water (18) multiplied by the molecular weight of carbon dioxide (44).

[0024] The biomass ratio of flexible polyurethane foam is preferably 25% or more in order to reduce the environmental impact of flexible polyurethane foam.

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

[0026] The polyol may contain a petroleum-derived polyol in addition to the plant-derived polyol. The reactivity of the petroleum-derived polyol is intermediate between the reactivity of the first polyol and the reactivity of the second polyol, and therefore has the effect of widening the range of the appropriate amount of catalyst, which contributes to improving moldability. When the polyol contains a petroleum-derived polyol, the mass ratio of the plant-derived polyol to 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.

[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 an alkylene oxide such as ethylene oxide (EO) or propylene oxide (PO) to a polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, or sucrose.

[0028] The polyether polyol is preferably a polyether polyol having a weight average molecular weight of 500 to 12,500 (preferably 800 to 6,000, more preferably 1,000 to 3,000) and a functionality of 2 to 6 (preferably 2 or 3).

[0029] The polymer polyol is exemplified by a polymer polyol obtained by graft copolymerization of vinyl monomers such as acrylonitrile and styrene in a polyether polyol having a functionality of 2 or 3 as a base polyol. The base polyol is exemplified by a polyether polyol 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 a 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 polyester polyols obtained by ring-opening addition polymerization of lactones such as ε-caprolactone. Examples of adipate-based polyester polyols include polyester polyols obtained by polycondensation of polyfunctional carboxylic acids and polyfunctional hydroxy compounds.

[0031] When a low molecular weight polyhydric alcohol such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, glycerin, trimethylolpropane, pentaerythritol, or sorbitol is used, the polyhydric alcohol is also included in the polyol.

[0032] The isocyanate is a compound having a plurality of isocyanate groups, and examples thereof 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, and aliphatic isocyanates such as hexamethylene diisocyanate (HDI), or free isocyanate prepolymers obtained by reacting these with polyols, and modified isocyanates such as carbodiimide-modified isocyanates. At least one of these isocyanates is used.

[0033] The index is the equivalent ratio of the isocyanate group of the isocyanate to the functional group such as the hydroxyl group of the polyol that can react with the isocyanate. From the viewpoint of reaction stability, the index is 91 or more, preferably 93 or more, and more preferably 95 or more, and from the viewpoint of reducing heat generation during foaming, the index is 125 or less, preferably 115 or less, and more preferably 110 or less.

[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 the catalyst include tertiary amines such as triethylenediamine, N,N-dimethylaminoethanol, 6-dimethylamino-1-hexanol, and N,N',N'-trimethylaminoethylpiperazine, organometallic compounds such as stannous octoate and stannous octoate, acetates, and alkali metal alcoholates. There is no particular restriction on the ratio of the catalyst in the composition, but it is preferably 0.1 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the polyol. This is for the purpose of promoting the resinification reaction and reducing the non-uniformity of the cell structure.

[0035] Examples of the foam stabilizer include silicone compounds such as organopolysiloxane, organopolysiloxane-polyoxyalkylene copolymer, polyalkenylsiloxane having a polyoxyalkylene side chain, silicone-grease copolymer, etc., anionic surfactants such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, etc., polyether siloxane, and phenolic compounds. The proportion of the foam stabilizer in the composition is not particularly limited, but 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 the blowing agent include water, carbon dioxide gas, and hydrohaloolefin. When the blowing agent is water, the ratio of the blowing agent in the composition is preferably 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the polyol.

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

[0038] Flexible polyurethane foams can be produced by a known foaming method in which the composition is stirred and mixed to react with the polyol and isocyanate. Foaming methods include slab foaming and mold foaming. Slab foaming is a method in which the mixed composition is discharged onto a belt conveyer and foamed at atmospheric pressure and room temperature. Mold foaming is a method in which the mixed composition is filled into a mold (forming die) and foamed within the mold.

[0039] Examples of applications of the flexible polyurethane foam include bedding, chair cushions and backrests, sofas, cushioning materials, sound absorbing materials, building materials, cleaning sponges, and hydroponic culture media. Examples of bedding include mattresses, quilts, mattresses, and pillows.

[0040] The impact resilience of a flexible polyurethane foam conforming to JIS K6400-3:2011 is preferably 20% or more, and more preferably 30% or more. The impact resilience is usually 90% or less.

[0041] The elongation of the flexible polyurethane foam according to JIS K6400-5:2012 (test piece is No. 2) is preferably 100% or more, particularly 130% or more. The elongation is usually 500% or less.

[0042] The tear strength of a flexible polyurethane foam according to JIS K6400-5:2012, Method B is preferably 4.0 N / cm or more. The tear strength is usually 10 N / cm or less. EXAMPLES

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

[0044] [Table 1]

[0045] [Table 2]

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

[0047] First polyol 1: derived from castor oil, biomass ratio 95.7%, hydroxyl value 56 mg KOH / g, average molecular weight 3000, functionality 3.0, all hydroxyl groups are primary hydroxyl groups First polyol 2: derived from corn, biomass ratio 100%, hydroxyl value 56 mg KOH / g, average molecular weight 2000, functionality 2.0, all hydroxyl groups are primary hydroxyl groups First polyol 3: derived from corn, biomass ratio 100%, hydroxyl value 187 mg KOH / g, average molecular weight 600, functionality 2.0, all hydroxyl groups are primary hydroxyl groups Second polyol 1: derived from castor oil, biomass ratio 93%, hydroxyl value 153 mgKOH / g, average molecular weight 990, functionality 2.7, all hydroxyl groups are secondary hydroxyl groups Second polyol 2: derived from castor oil, biomass ratio 100%, hydroxyl value 90 mg KOH / g, average molecular weight 2182, functionality 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 mg KOH / g, average molecular weight 3000, functionality 3 Petroleum-derived polyol 3: hydroxyl value 45 mg KOH / g, average molecular weight 3740, functionality 3 Petroleum-derived polyol 4: hydroxyl value 112 mg KOH / g, average molecular weight 1000, functionality 2 Petroleum-derived polyol 5: hydroxyl value 56 mg KOH / g, average molecular weight 2000, functionality 2 Isocyanate: Toluene diisocyanate (TDI), 2,4-toluene diisocyanate 75-85%, 2,6-toluene diisocyanate 15-25% Catalyst 1: Amine-based catalyst, DABCO® 33LX Catalyst 2: Amine catalyst, TEDA® L33 Catalyst 3: Amine-based catalyst, DABCO® BL-22 Catalyst 4: Amine-based catalyst, DABCO® NE300 Catalyst 5: Metal catalyst, KOSMOS® T9 Catalyst 6: Metal catalyst, Neostan® U-28 Foam stabilizer 1: VORASURF (registered trademark) SF2904 Foam stabilizer 2: TEGOSTAB (registered trademark) B8244 Foam stabilizer 3: TEGOSTAB (registered trademark) B8228 Opening agent: Actocol (registered trademark) EP-505S Blowing agent: Water

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

[0049] Actocol (registered trademark) 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, since it is used as a connecting agent, it is not included in the polyols.

[0050] Compositions were prepared by blending the raw materials as shown in Tables 1 and 2, and flexible polyurethane foams in Examples 1-25 and Comparative Examples 1-5 were produced by slab foaming. The biomass degree of the flexible polyurethane foam was calculated using the above formula (1). The density was determined by a method conforming to JIS K7222:2005. The 40% hardness was determined by a method conforming to JIS K6400-2:2012 Method A. The air permeability was determined by a method conforming to JIS K6400-7:2012 Method B. The rebound resilience was determined by a method conforming to JIS K6400-3:2011. The tensile strength and elongation were determined by a method conforming to JIS K6400-5:2012 (test pieces were No. 2 type). The tear strength was determined by a method conforming to JIS K6400-5:2012 Method B. The 75% compressive residual strain was determined by a method conforming to JIS K6400-4:2004 Method A.

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

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

[0053] Examples 10-14 each contain 45-80 parts by mass of the first polyol and 20-55 parts by mass of the petroleum-based polyol out of 100 parts by mass of the polyol. The biomass degree is 30% or more and less than 60%, the rebound resilience is 20% or more (particularly 30% or more), the elongation is 100% or more (particularly 180% or more), the tear strength is 4.0 N / cm or more (particularly 6.0 N / cm or more), and the 75% compression set is less than 5% (particularly less than 3.5%).

[0054] Examples 15 and 16 each contained 100 parts by mass of the first polyol out of 100 parts by mass of the polyol. The biomass degree was 60% or more and less than 70%, the rebound resilience was 20% or more (particularly 30% or more), the elongation was 100% or more (particularly 140% or more), the tear strength was 4.0 N / cm or more (particularly 5.0 N / cm or more), and the 75% compression set was less than 5% (particularly 4.0% or less).

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

[0056] Examples 19 and 20 each contain 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 degree was 60% or more and less than 70%, the rebound resilience 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 set was less than 5%.

[0057] Examples 21-25 each contain 70-80 parts by mass of the first polyol, 10-30% by mass of the second polyol, and 0-10 parts by mass of the petroleum-based polyol, out of 100 parts by mass of polyol. The biomass degree was 60% or more and less than 75%, the rebound resilience was 20% or more (particularly 25% or more), the elongation was 125% or more, the tear strength was 4.0 N / cm or more, and the 75% compression set 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. The biomass degree is 0%, the rebound resilience is 46%, the elongation is 148%, the tear strength is 4.7 N / cm, and the 75% compression set is 1.6%. Comparative Example 2-5 contains 30-100% by mass of a second polyol out of 100 parts by mass of polyol and 0-70 parts by mass of a petroleum-based polyol in order to increase the biomass degree.

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

[0060] In contrast, in Examples 1-25, the biomass degree was 25% or more, the rebound resilience was 20% or more, the elongation was 100% or more, and the tear strength was 4.0 N / cm or more. According to the Examples, it was revealed that a composition containing a plant-derived polyol (first polyol) having a primary hydroxyl group can produce a flexible polyurethane foam having a biomass degree of 25% or more, a rebound resilience of 20% or more, an elongation of 100% or more, and a tear strength of 4.0 N / cm or more.

[0061] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and it can be easily imagined that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

Claims

1. A flexible polyurethane foam obtained from a composition containing a polyol including a plant-derived polyol and an isocyanate, The biomass ratio is 25% or more, The elongation according to JIS K6400-5:2012 is 100% or more, The resilience according to JIS K6400-3:2011 is 30% or more, The tear strength according to JIS K6400-5:2012 B method is 4.0 N / cm or more, The plant-derived polyol includes a first polyol having a primary hydroxyl group, The first polyol is a polyol made from castor oil as a raw material, and has a functionality of 2.0 or more and less than 3.5 and a hydroxyl value of less than 60 mgKOH / g.

2. The plant-derived polyol includes a second polyol having a secondary hydroxyl group, 2. The flexible polyurethane foam according to claim 1, wherein the proportion of the mass of the plant-derived polyol in the mass of the polyol is 40% or more.

3. the plant-derived polyol is the first polyol, 2. The flexible polyurethane foam according to claim 1, having a biomass ratio of 30% or more.

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