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 a polyol, including a plant-derived polyol, and an isocyanate, wherein the plant-derived polyol includes a first polyol having primary hydroxyl groups. It is preferable that the hydroxyl value of the first polyol is less than 60 mg KOH / g, and it is also preferable that the biomass content of the flexible polyurethane foam is 25% or more. The plant-derived polyol may also include a second polyol having secondary hydroxyl groups, in which case the mass ratio of the plant-derived polyol to the total polyol mass is 40% or more.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 technology]

[0002] Patent Document 1 discloses a prior art technique that uses a composition containing a plant-derived polyol to reduce the environmental impact of flexible polyurethane foams. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-2578 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 approximately 32% in accordance with JIS K6400-3, but an average elongation of approximately 90% in accordance with JIS K6400-5, leaving room for improvement.

[0005] The present invention has been made to solve this problem, and an object of the present invention is to provide a flexible polyurethane foam that can achieve both high impact resilience and high elongation, and that is obtained from a composition containing a plant-derived polyol. [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, wherein the polyol comprises a plant-derived polyol, and the plant-derived polyol comprises a first polyol having a primary hydroxyl group.

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

[0008] In a third aspect, in the first or second aspect, the biomass degree of the flexible polyurethane foam is 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 mass ratio of the plant-derived polyol to 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 mass ratio of the plant-derived polyol to 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 a 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 Method B of JIS K6400-5:2012. [Effects of the Invention]

[0015] According to the present invention, the first polyol, which is a plant-derived polyol, contains a hydroxy group (primary hydroxyl group) with one carbon atom bonded to a carbon atom already bonded to a hydroxy group. The primary hydroxyl group has only one hydrocarbon group bonded to the carbon atom to which the hydroxy group is bonded, resulting in little steric hindrance. Therefore, the first polyol has high reactivity with isocyanates for resinification. This allows the flexible polyurethane foam to achieve both high impact resilience and elongation. DETAILED DESCRIPTION OF THE INVENTION

[0016] A preferred embodiment of the present invention will be described below. Flexible polyurethane foams are 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, which reduces steric hindrance and improves 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 this allows a crosslinked structure with an appropriate crosslink density and number of crosslinking branching points to be formed, and improves the mechanical properties such as impact resilience of a flexible polyurethane foam obtained from a composition containing the first polyol.

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

[0020] Plant-derived polyols are preferably composed of a first polyol (i.e., all plant-derived polyols are the first polyol), but they may also contain a second polyol. The second polyol contains a hydroxyl group (secondary hydroxyl group) with two carbon atoms bonded to the carbon atom to which the hydroxyl group is bonded. The second polyol has two hydrocarbon groups bonded to the carbon atom to which the hydroxyl group is bonded, which creates significant steric hindrance, reducing the reactivity of the polyol, but can complement plant-derived materials. Primary and secondary hydroxyl groups can be analyzed using carbon-13 nuclear magnetic resonance spectroscopy.

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

[0022] The biomass degree can be calculated 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 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 content of flexible polyurethane foam is preferably 25% or more, in order to reduce the environmental impact of flexible polyurethane foam.

[0025] When the plant-derived polyol is the first polyol, the biomass content 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 a 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, which has the effect of widening the range of the appropriate catalyst amount and contributing to improved 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 content of the flexible polyurethane foam.

[0027] Examples of petroleum-derived polyols include polyether polyols, polymer polyols, polyester polyols, etc. Examples of polyether polyols 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 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] Examples of polymer polyols include polymer polyols obtained by graft copolymerizing vinyl monomers such as acrylonitrile and styrene with a polyether polyol having two or three functional groups as the 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 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 multiple 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), as well as 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 isocyanate groups of the isocyanate to functional groups such as hydroxyl groups 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 blowing agent. The catalyst primarily 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 stannous octoate and stannous octoate, acetates, and alkali metal alcoholates. There are no particular restrictions on the proportion of catalyst in the composition, but it is preferably 0.1 to 5.0 parts by mass per 100 parts by mass of the polyol. This is to promote the resinification reaction and reduce non-uniformity in the cell structure.

[0035] Examples of foam stabilizers include silicone compounds such as organopolysiloxanes, organopolysiloxane-polyoxyalkylene copolymers, polyalkenylsiloxanes having polyoxyalkylene side chains, and silicone-grease copolymers, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate, polyether siloxanes, and phenolic compounds. There are no particular restrictions on the proportion of the foam stabilizer 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 the polyol.

[0036] Examples of the blowing agent include water, carbon dioxide gas, and hydrohaloolefin. When the blowing agent is water, the proportion 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 known foaming methods in which the composition is stirred and mixed to react 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 conveyor 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 flexible polyurethane foams 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, comforters, mattress pads, and pillows.

[0040] The impact resilience of flexible polyurethane foams conforming to JIS K6400-3:2011 is preferably 20% or more, and particularly 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, and is usually 10 N / cm or less. [Example]

[0043] The present invention will be explained 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 the flexible polyurethane foams in Examples 1-16. Table 2 shows the blends of raw materials for the 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 content 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 content 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 content 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 content 93%, hydroxyl value 153 mg KOH / g, average molecular weight 990, functionality 2.7, all hydroxyl groups are secondary hydroxyl groups Second polyol 2: derived from castor oil, biomass content 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 mg KOH / g, average molecular weight 3300, number of functional groups 3 Petroleum-derived polyol 2: hydroxyl value 56 mg KOH / g, average molecular weight 3000, number of functional groups 3 Petroleum-derived polyol 3: hydroxyl value 45 mg KOH / g, average molecular weight 3740, number of functional groups 3 Petroleum-derived polyol 4: hydroxyl value 112 mg KOH / g, average molecular weight 1000, number of functional groups 2 Petroleum-derived polyol 5: hydroxyl value 56 mg KOH / g, average molecular weight 2000, number of functional groups 2 Isocyanate: Toluene diisocyanate (TDI), 2,4-toluene diisocyanate 75-85%, 2,6-toluene diisocyanate 15-25% Catalyst 1: Amine catalyst, DABCO® 33LX Catalyst 2: Amine catalyst, TEDA® L33 Catalyst 3: Amine catalyst, DABCO® BL-22 Catalyst 4: Amine 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 Foaming 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 quotient 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, but because it was used as a connecting agent, it is not included in the polyol category.

[0050] Compositions containing the raw materials listed in Tables 1 and 2 were prepared, and flexible polyurethane foams in Examples 1-25 and Comparative Examples 1-5 were produced by slab foaming. The biomass content of the flexible polyurethane foams was calculated using the above formula (1). The density was determined according to the method specified in JIS K7222:2005. The 40% hardness was determined according to the method specified in JIS K6400-2:2012, Method A. The air permeability was determined according to the method specified in JIS K6400-7:2012, Method B. The rebound resilience was determined according to the method specified in JIS K6400-3:2011. The tensile strength and elongation were determined according to the method specified in JIS K6400-5:2012 (test specimens were size 2). The tear strength was determined according to the method specified in 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 contained 40 parts by mass of the first polyol and 60 parts by mass of the petroleum-based polyol, based on 100 parts by mass of polyol. The biomass content 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 contained 100 parts by mass of polyol, 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. The biomass content was 25% or more and less than 30%, the rebound resilience 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 set was less than 5% (especially less than 3.5%).

[0053] Examples 10-14 contained 45-80 parts by mass of a first polyol and 20-55 parts by mass of a petroleum-based polyol, based on 100 parts by mass of polyol. The biomass content was 30% or more and less than 60%, the rebound resilience 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 set was less than 5% (especially 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 polyol, and had a biomass content of 60% or more and less than 70%, a rebound resilience of 20% or more (particularly 30% or more), an elongation of 100% or more (particularly 140% or more), a tear strength of 4.0 N / cm or more (particularly 5.0 N / cm or more), and a 75% compression set of less than 5% (particularly 4.0% or less).

[0055] Examples 17 and 18 each contained 50-60 parts by mass of a first polyol, 20% by mass of a second polyol, and 20-30 parts by mass of a petroleum-based polyol, based on 100 parts by mass of polyol. The biomass content was 40% or more and less than 60%, the rebound resilience 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 set 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, based on 100 parts by mass of polyol. The biomass content 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 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, based on 100 parts by mass of polyol. The biomass content 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 contained 100 parts by mass of petroleum-based polyol out of 100 parts by mass of polyol. The biomass content was 0%, the rebound resilience was 46%, the elongation was 148%, the tear strength was 4.7 N / cm, and the 75% compression set was 1.6%. Comparative Examples 2-5 contained 30-100% by mass of a second polyol and 0-70 parts by mass of a petroleum-based polyol out of 100 parts by mass of polyol in order to increase the biomass content.

[0059] In Comparative Examples 2-5, as the comparative example number increases, the proportion of the second polyol in the polyols increases and the proportion of the petroleum-based polyol decreases. As the proportion of the second polyol increases, the biomass content increases, but the rebound resilience, elongation, and tear strength decrease. However, when the proportion of the second polyol reached 100% (Comparative Example 5), the elongation and tear strength were comparable to those of Comparative Example 1, where the proportion of the petroleum-based polyol was 100%. However, the rebound resilience continued to decrease as the proportion of the second polyol increased, with the rebound resilience of Comparative Example 4 being less than 30% and that of Comparative Example 5 being 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. The examples reveal 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, the rebound resilience of 20% or more, the elongation was 100% or more, and the tear strength was 4.0 N / cm or more.

[0061] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily inferred that various improvements and modifications are possible within the scope 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 plant-derived polyol is a flexible polyurethane foam containing a first polyol having a primary hydroxyl group.

2. 2. The flexible polyurethane foam according to claim 1, wherein the first polyol has a hydroxyl value of less than 60 mg KOH / g.

3. 3. The flexible polyurethane foam according to claim 1, wherein the biomass content is 25% or more.

4. the plant-derived polyol includes a second polyol having a secondary hydroxyl group, 3. The flexible polyurethane foam according to claim 1, wherein the mass ratio of the plant-derived polyol to the mass of the polyol is 40% or more.

5. the polyol comprises a petroleum-derived polyol; 3. The flexible polyurethane foam according to claim 1, wherein the mass ratio of the plant-derived polyol to the mass of the polyol is 40% or more.

6. the plant-derived polyol is the first polyol, 3. The flexible polyurethane foam according to claim 1, wherein the biomass content is 30% or more.

7. The flexible polyurethane foam according to claim 1 or 2, having a rebound resilience in accordance with JIS K6400-3:2011 of 20% or more.

8. The flexible polyurethane foam according to claim 1 or 2, having an elongation in accordance with JIS K6400-5:2012 of 100% or more.

9. The flexible polyurethane foam according to claim 1 or 2, having a tear strength of 4.0 N / cm or more according to Method B of JIS K6400-5:2012.

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