JP7443696B2 - Polyol composition for molding flexible polyurethane foam - Google Patents

Description

The present invention relates to a polyol composition for molding flexible polyurethane foam and a flexible polyurethane foam using the composition.

Flexible polyurethane foam is used in a wide range of applications, including household goods, automobile materials, clothing, sports and leisure goods, medical materials, and civil engineering and construction materials. Among these application fields, in addition to the functions traditionally required for cushioning materials such as automobile seats and wheelchairs, there is also the need for stiffness during the initial compression when sitting, and for the lateral movement of the lower back and buttocks of occupants when driving around curves. There is a need to reduce the feeling of wobbling caused by tilting in one direction. In order to achieve these goals, it is necessary to maintain a more stable sitting posture by creating a hardness distribution that makes it difficult for soft polyurethane foam to develop hardness during initial compression, but is more likely to develop hardness during high compression. .

Various efforts have been made in the past as means to develop this hardness distribution. For example, a seat cushion structure with a laminated structure in which highly elastic polyurethane foam is arranged in the upper layer (seat side) and viscoelastic foam is arranged in the lower layer (bottom side) is disclosed (Patent Document 1). According to this, the lower layer side viscoelastic foam indirectly provides a soft fit feeling to the occupant via the upper layer side high elastic foam, and the upper layer high elastic foam directly provides a cushioned feeling to the occupant. Although these synergistic effects improve seating comfort, problems arise, such as an increase in the number of parts and an increase in the number of steps for integrating the foams by adhesion or the like. Further, a technique has been disclosed in which hardness distribution is expressed by changing the density of the sheet for each region (Patent Document 2). However, when the hardness is adjusted by changing the density, the density must be increased in order to increase the hardness, which leads to an increase in cost. Additionally, it is necessary to mold each part separately, which increases the number of man-hours. In addition, the main polymerizable group (reactive group) of the crosslinking agent component contained in the polyol composition is an ethylene oxide group, the inclusion of glycerin, and the control of the shape of the foam cells. A technique for developing hardness distribution even at the same density has been disclosed (Patent Document 3). However, these factors alone are insufficient to reduce the initial compression hardness felt when sitting and to develop a hardness distribution that suppresses the feeling of wobbling.

Utility Model Publication No. 6-19604 Japanese Patent Application Publication No. 2002-300936 International Publication No. 2017/022824

The present invention has been made in view of the above-mentioned background art, and provides a polyol composition for molding a flexible polyurethane foam that has a hardness distribution that provides good seating comfort when used as a cushioning material, and a flexible polyurethane foam using the composition. The purpose is to provide.

That is, the present invention includes the embodiments shown below.

(1) A polyol composition for molding flexible polyurethane foam containing a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a crosslinking agent (E). A soft material containing a carbohydrate (E-1) as E), characterized in that the amount of the carbohydrate (E-1) added is 0.1 to 5% by mass based on the polyol component (A). Polyol composition for molding polyurethane foam.

(2) The polyol composition for molding flexible polyurethane foam according to (1) above, wherein the carbohydrate (E-1) contains at least one selected from monosaccharides to decasaccharides.

(3) The polyol composition for molding flexible polyurethane foam according to (1) or (2) above, wherein the average number of sugar chains of the carbohydrate (E-1) is 1.0 or more and 9.0 or less.

(4) Polyol component (A) produced using at least one selected from a multimetal cyanide complex catalyst, a phosphazene catalyst, and an imino group-containing phosphazenium salt as a catalyst, with a total unsaturation degree of 0.001 to 0.04meq. /g of polyoxyalkylene polyol (A-1).

(5) A flexible polyurethane foam molding composition comprising the flexible polyurethane foam molding polyol composition according to any one of (1) to (4) above, and a polyisocyanate component (F), wherein the polyisocyanate component Component (F) contains diphenylmethane diisocyanate in a range of 50 to 85% by mass, and the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate contained in the diphenylmethane diisocyanate is the total amount of the diphenylmethane diisocyanate. A flexible polyurethane foam molding composition characterized in that the content is 10 to 50% by mass.

(6) A flexible polyurethane foam obtained by reaction foaming the flexible polyurethane foam molding composition described in (5) above.

(7) In a two-layer foam cut out from a flexible polyurethane foam molded so that the upper mold side is the lower surface and the lower mold side is the upper surface, every 45% of the thickness is cut from the upper end surface toward the lower surface. The flexible polyurethane foam according to (6) above, wherein the hardness ratio of the upper foam is 50 to 85% when the average value of the 25% compression hardness of the foam of each layer is 100.

(8) The apparent density is 30 to 70 kg/m ³ , the 25% compression hardness of the skinned foam test piece is 100 to 350 N/314 cm ² , and the elongation is 100% or more. The flexible polyurethane foam according to (6) or (7) above.

(9) The flexible polyurethane foam according to any one of (6) to (8) above, which has a rebound modulus of 45 to 75% and a wet heat compressive strain of less than 20%.

By using the polyol composition for molding flexible polyurethane foam of the present invention, it is possible to obtain a flexible polyurethane foam that has a hardness distribution that provides good seating comfort when used as a cushioning material.

The present invention will be explained in more detail.

The polyol composition for molding flexible polyurethane foam in the present invention contains a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a crosslinking agent (E) shown below.

The polyol component (A) is polyadded with the polyisocyanate component (F) to form polyurethane, and in the present invention, it is at least one selected from the group consisting of polyether polyols and polyester polyols. desirable. Further, it is more desirable to have a number average molecular weight of 1,000 to 10,000 and a nominal number of functional groups of 2 or more. When the number average molecular weight is less than the lower limit, the resulting foam tends to lack flexibility, and when it exceeds the upper limit, the hardness of the foam tends to decrease. Moreover, when the number of nominal functional groups is less than 2, there is a possibility that a problem such as deterioration of wet heat compression strain, which is an index of durability, may occur. In addition. The nominal number of functional groups refers to the theoretical average number of functional groups (the number of active hydrogen atoms per molecule) assuming that no side reactions occur during the polymerization reaction of the polyol.

As the polyether polyol, for example, polypropylene ether polyol, polyethylene polypropylene ether polyol (hereinafter referred to as PPG), polytetramethylene ether glycol (hereinafter referred to as PTG), etc. can be used, and as the polyester polyol, for example, polycondensation Polyester polyols consisting of adipic acid and diol, which are type polyester polyols, and polycaprolactone polyols, which are lactone type polyester polyols, can be used.

In the present invention, from the viewpoint of improving the durability of the foam, the polyol component (A) is produced using at least one selected from a multimetal cyanide complex catalyst, a phosphazene catalyst, and an imino group-containing phosphazenium salt as a catalyst. In addition, the total unsaturation degree is 0.001 to 0.04 meq. /g of polyoxyalkylene polyol (A-1). An increase in the total unsaturation degree of the polyol (A-1) means that the monool component having an unsaturated group at the terminal increases, and the total unsaturation degree is 0.04 meq. If it is larger than /g, there is a risk that the durability of the foam will decrease as the crosslinking density of the foam decreases. Also 0.001meq. If it is smaller than /g, it is not preferable because it requires a lot of manufacturing time.

In addition, in the present invention, a polyether polyol having a polyoxyalkylene chain consisting of a copolymer of oxyethylene and oxypropylene is added to the polyol component (A) for the purpose of promoting foam breaking of the flexible polyurethane foam. It is preferable to include. The number average molecular weight of the polyether polyol is preferably 4,000 to 8,000, more preferably 6,000 to 8,000. Further, it is preferable that the nominal number of functional groups is 2 to 4. Furthermore, the amount of oxyethylene units in the polyether polyol is preferably 60 to 90% by mass, more preferably 60 to 80% by mass. By setting the oxyethylene unit content to 60 to 90% by mass, the hardness distribution of the foam can be easily obtained, and the durability can be further improved. Further, from the viewpoint of storage stability at low temperatures, the copolymer consisting of oxyethylene and oxypropylene is preferably a random copolymer.

The amount of the polyether polyol added is preferably 0.5 to 5% by mass based on the polyol component (A). If it is less than the lower limit, the moldability of the foam may deteriorate, and if it exceeds the upper limit, the elongation rate of the foam may decrease.

For the purpose of hardness adjustment, it is preferable to use a polymer polyol obtained by polymerizing a vinyl monomer in a polyol by a conventional method as the polyol component (A) of the present invention. Examples of such polymer polyols include those obtained by polymerizing and stably dispersing a vinyl monomer in a polyalkylene polyol such as the above-mentioned PPG in the presence of a radical initiator. Examples of vinyl monomers include acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl methacrylate, and alkyl methacrylate, with acrylonitrile and styrene being preferred. Examples of such polymer polyols include EL-910 and EL-923 manufactured by AGC, and FA-728R manufactured by Sanyo Chemical Industries.

As the catalyst (B), various urethanization catalysts known in the art can be used, such as triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N ,N,N',N'-tetramethylhexamethylenediamine, N,N,N',N',N''-pentamethyldiethylenetriamine, bis-(2-dimethylaminoethyl)ether, triethylenediamine, 1,8 -Diaza-bicyclo[5.4.0]undecene-7,1,2-dimethylimidazole, dimethylethanolamine, N,N-dimethyl-N-hexanolamine, and organic acid salts thereof, stannous octoate, naphthene Also included are organometallic compounds such as zinc oxide. Also preferred are amine catalysts having active hydrogen such as N,N-dimethylethanolamine and N,N-diethylethanolamine.

The amount of catalyst added is preferably 0.01 to 10% by mass based on the polyol component (A). If it is less than the lower limit, curing tends to be insufficient, and if it exceeds the upper limit, moldability may deteriorate.

As the foam stabilizer (C), ordinary surfactants are used, and organic silicon-based surfactants are preferably used. For example, SZ-1327, SZ-1325, SZ-1336, SZ-3601 manufactured by Dow Corning Toray, Y-10366, L-5309 manufactured by Momentive, B-8724LF2, B-8715LF2 manufactured by Evonik, etc. Can be mentioned. The amount of these foam stabilizers added is preferably 0.1 to 3% by mass based on the polyol component (A).

Water is mainly used as the blowing agent (D). Water reacts with isocyanate groups to form highly hard urea groups and also generates carbon dioxide gas, which can cause foaming. Additionally, any blowing agent may be used in addition to water. For example, a small amount of a low boiling point organic compound such as cyclopentane or isopentane may be used in combination, or air, nitrogen gas, or liquefied carbon dioxide may be mixed and dissolved in the stock solution using a gas loading device to cause foaming. The amount of the blowing agent added is usually 0.5 to 10% by mass based on the polyol component (A), but when obtaining a low density flexible polyurethane foam with an apparent density of less than 40 kg/m ³ , the amount added is 3.0 to 6% by mass. It is preferably 0% by weight, more preferably 3.0 to 5.5% by weight. If the upper limit is exceeded, foaming may become difficult to stabilize, and if it is less than the lower limit, the density of the foam may not be sufficiently lowered.

The crosslinking agent (E) in the present invention contains a carbohydrate (E-1). The carbohydrate (E-1) preferably contains at least one selected from monosaccharides to decasaccharides, and more preferably at least one selected from monosaccharides to hexasaccharides. Note that monosaccharides are the smallest units of carbohydrates, and disaccharides to decasaccharides refer to 2 to 10 monosaccharides dehydrated and condensed to form glycosidic bonds to form one molecule.

Among these, examples of monosaccharides include triose, tetrose, pentose, hexose, heptose, octose, nonose, and decose. These compounds may be aldoses or ketoses, and dialdoses (compounds that are sugar derivatives and have aldehyde groups at both ends of the carbon chain, such as tetraacetylgalactohexodialdose, idohexodialdose, xylopentodo) aldose, etc.), monosaccharides with multiple carbonyl groups (aldoalkoketoses such as othone, onose, etc.), monosaccharides with methyl groups (methyl sugars such as altromethylose, etc.), acyl groups (especially C2 -C4 acyl group, etc.) (acetyl form of the above-mentioned aldose, for example, acetyl form such as aldehyde glucose pentaacetyl compound, etc.), carbohydrates into which a carboxyl group has been introduced (saccharide acid or uronic acid, etc.), liosaccharide , amino sugar, deoxy sugar, etc.

Examples of such monosaccharides include tetrose (erythrose, threolose, etc.), pentose (arabinose, ribose, lyxose, deoxyribose, xylose, etc.), hexose (allose, altrose, glucose, mannose, gulose, idose, galactose, Examples include fructose, sorbose, fucose, rhamnose, talose, galacturonic acid, glucuronic acid, mannuronic acid, glucosamine, etc.).

Further, the monosaccharide may be a cyclic isomer having a cyclic structure formed by a hemiacetal bond. The monosaccharide does not need to have optical rotation, and may be any of the D-type, L-type, and DL-type. Further, it may be in a crystalline state or a liquid state, and may be a hydrate or contain water. These monosaccharides can be used alone or in combination of two or more. In particular, isomerized liquid sugars that are liquid at room temperature, such as high fructose corn syrup, high fructose corn syrup, and high-fructose corn syrup, are useful for improving workability during the preparation of polyol compositions for molding flexible polyurethane foams. More preferred in terms of storage stability.

Disaccharides include trehalose (e.g. α,α-trehalose, β,β-trehalose, α,β-trehalose, etc.) cozybiose, nigerose, maltose, isomaltose, sophorose, laminaribiose, cellobiose, gentiobiose, lactose. , sucrose, palatinose, melibiose, rutinose, primeverose, turanose, and the like. These monosaccharides and disaccharides can be used alone or in combination of two or more, but as mentioned above, a room-temperature liquid mixture of carbohydrates that is liquid at room temperature, or a room-temperature liquid mixture with a hydrophilic polyol such as ethylene glycol, diethylene glycol, or glycerin. It is more preferable to use it as

Trisaccharides to decasaccharides are generally also called oligosaccharides (hereinafter, trisaccharides to decasaccharides may be referred to as oligosaccharides), and are homooligosaccharides in which 3 to 10 molecules of monosaccharides are dehydrated and condensed via glycosidic bonds. and hetero-oligosaccharides, in which at least two or more types of 3 to 10 molecules of monosaccharides and/or sugar alcohols are dehydrated and condensed via glycosidic bonds. The oligosaccharides that can be used in the present invention are preferably trisaccharides to decasaccharides, and more preferably trisaccharides to hexasaccharides. Note that these oligosaccharides may have a cyclic structure, and may be anhydrous or hydrated. Furthermore, in the oligosaccharide, a monosaccharide and a sugar alcohol may be bonded. These oligosaccharides can be used alone or in combination of two or more, and can also be used in combination with monosaccharides, disaccharides, and polysaccharides. Note that the oligosaccharide may be an oligosaccharide composition composed of a plurality of sugar components. Even such an oligosaccharide composition may be simply referred to as an oligosaccharide. Among oligosaccharides, those that are solid at room temperature are preferably used after being liquefied at room temperature by mixing with other carbohydrates or hydrophilic polyols such as glycerin.

Examples of trisaccharides include homo-oligosaccharides such as maltotriose, isomaltotriose, panose, and cellotriose; hetero-oligosaccharides such as manninotriose, solatriose, melezitose, planteose, gentianose, umbelliferose, lactosucrose, and raffinose. It will be done.

Examples of the tetrasaccharide include homo-oligosaccharides such as maltotetraose and isomaltotetraose; hetero-oligosaccharides such as stachyose, cellotetraose, scorodose, liquinose, and telolaose, in which a sugar or sugar alcohol is bound to the reducing end of panose.

Examples of pentasaccharides include homo-oligosaccharides such as maltopentaose and isomaltopentaose; hetero-oligosaccharides such as pentaose in which a disaccharide is bonded to the reducing end of panose.

Examples of hexasaccharides include homooligosaccharides such as maltohexaose and isomaltohexaose.

Examples of the cyclic oligosaccharide include α-cyclodextrin (hexasaccharide), β-cyclodextrin (heptasaccharide), and γ-cyclodextrin (octasaccharide).

The oligosaccharide may be a reduced type (maltose type) or a non-reduced type (trehalose type).

Examples of polysaccharides include amylose, amylopectin, glycogen, cellulose, agar, inulin, glucomannan, glycosaminoglycan (mucopolysaccharide), alginic acid, hyaluronic acid, chondroitic acid, heparin, and chitin.

Monosaccharides, disaccharides, oligosaccharides, and mixtures thereof may be modified with ethers or esters to partially modify their hydroxyl groups for the purpose of improving the miscibility of carbohydrates and other components constituting the polyol molding composition. It's okay. However, since the effect of the present invention decreases due to a decrease in the concentration of hydroxyl groups due to modification, it is preferable that the amount of hydroxyl groups that can be modified is 30 mol % or less of the total hydroxyl groups.

The number average molecular weight of the carbohydrate (E-1) is preferably 180 to 2,500, more preferably 180 to 1,800. If the upper limit is exceeded, the moldability of the foam and the elongation rate of the foam may deteriorate.

The average number of sugar chains of the carbohydrate (E-1) is preferably 1.0 or more and 9.0 or less, more preferably more than 1.0 and 9.0 or less, and most preferably 1.5 or more. It is 9.0 or less. Here, the number of sugar chains is the number of linked monosaccharides, and the average number of sugar chains is the average number of sugar chains of each component contained in the carbohydrate (E-1). If it is less than the lower limit, it is difficult to obtain a sufficient elongation rate, and if it exceeds the upper limit, the moldability of the foam and the elongation rate of the foam may deteriorate.

Furthermore, the average number of hydroxyl groups in the carbohydrate (E-1) is preferably 0.5 times or more the average number of carbon atoms. Here, the average number of hydroxyl groups is the average number of hydroxyl groups of each component in the carbohydrate (E-1), and the average number of carbon atoms is the average number of carbon atoms of each component in the carbohydrate (E-1). It is the average number of atoms.

The amount of carbohydrate (E-1) added is 0.1 to 5% by mass, preferably 0.1 to 4% by mass, more preferably 0.3 to 4% by mass based on polyol component (A). Mass%. If it is less than the lower limit, it is difficult to obtain the effect of developing hardness distribution, and if it exceeds the upper limit, the moldability of the foam and the elongation rate of the foam may deteriorate.

In addition, in the present invention, from the viewpoint of improving physical properties such as foam elongation and wet heat compression strain, alicyclic glycol is added as a crosslinking agent component other than carbohydrate (E-1) in the polyol composition for molding flexible polyurethane foam. and aromatic glycols (hereinafter also simply referred to as "cyclic glycol"). Cyclic glycols are compounds that have a ring structure, such as cyclohexanediol, cyclohexanedimethanol, hydroquinone bis(2-hydroxyethyl) ether, dihydroxydiphenylmethane, bisphenol A hydride, polyoxyethylene bisphenol ether, and Oxypropylene bisphenol ether and the like can be mentioned. Among these, 1,4-cyclohexanedimethanol and polyoxyethylene bisphenol A ether are preferred from the viewpoint of having a high effect of improving the moist heat compression strain of the resulting flexible polyurethane foam. The content of cyclic glycol is preferably 1.5 to 8% by mass, more preferably 1.5 to 6% by mass, based on the polyol component (A).

By using a polyol composition containing the above polyol component (A), catalyst (B), foam stabilizer (C), foaming agent (D), and crosslinking agent (E), it is possible to improve the seating resistance when used as a cushioning material. It becomes possible to obtain a soft polyurethane foam that is comfortable and has a hardness distribution in the vertical direction.

The polyisocyanate component (F) used in the production of the flexible polyurethane foam of the present invention is 4,4'-diphenylmethane diisocyanate (hereinafter referred to as 4,4'-MDI), 2,4'-diphenylmethane diisocyanate (hereinafter referred to as 2,4 '-MDI), 2,2'-diphenylmethane diisocyanate (hereinafter referred to as 2,2'-MDI), diphenylmethane diisocyanate (hereinafter referred to as MDI), polyphenylene polymethylene polyisocyanate (hereinafter referred to as P-MDI) are used as the isocyanate source. It is preferable. In the present invention, various modified products such as the above-described MDI, a mixture of MDI and P-MDI, a urethane modified product, a urea modified product, an allophanate modified product, a nurate modified product, a biuret modified product, etc. can also be used.

The MDI content of the polyisocyanate component (F) according to the present invention is preferably in the range of 50 to 85% by mass. If the MDI content exceeds 85% by mass, there is a risk that the storage stability of the polyisocyanate component at low temperatures and the durability of the resulting flexible polyurethane foam will decrease, while if it is less than 50% by mass, the crosslinking density will increase. The elongation of the flexible polyurethane foam may decrease, making it difficult to obtain sufficient foam strength.

Further, the total content of 2,2'-MDI and 2,4'-MDI (hereinafter referred to as isomer content) relative to the total amount of MDI is preferably 10 to 50% by mass.

If the content of 2,2'-MDI and 2,4'-MDI with respect to the total amount of MDI according to the present invention is less than 10% by mass, the storage stability at low temperatures of the polyisocyanate component may be impaired, and the isocyanate storage location may be It may be necessary to constantly heat the pipes, pipes, and inside of the foam molding machine. Furthermore, the molding stability of the flexible polyurethane foam may be impaired, and the foam may collapse during foaming. On the other hand, if it exceeds 50% by mass, the reactivity decreases, which may cause problems such as lengthening of the molding cycle, high cell foam ratio, and shrinkage after molding.

In the production of the flexible polyurethane foam of the present invention, various known additives and auxiliaries such as fillers such as calcium carbonate and barium sulfate, flame retardants, plasticizers, colorants, and antifungal agents are added as necessary. can be used.

In the present invention, a flexible polyurethane foam can be obtained from the polyol composition for molding flexible polyurethane foam and a polyisocyanate component, and has an apparent density of 30 kg/m ³ to 70 kg/m ³ and a skinned foam test piece of 25 Suitable is a flexible polyurethane foam having a hardness distribution in the foaming direction, with a % compression hardness of 100 to 350 N/314 cm ² , an elongation rate of 100% or more, a rebound modulus of 45 to 75%, and a moist heat compression strain of less than 20%. can be obtained.

Next, the method for manufacturing the flexible polyurethane foam of the present invention will be explained.

The flexible polyurethane foam of the present invention is produced by reacting a mixed solution of a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), a crosslinking agent (E), and a polyisocyanate component (F). Manufactured by foaming.

The molar ratio (NCO/active hydrogen) of all the isocyanate groups in the polyisocyanate composition of the present invention and all the active hydrogen groups in the active hydrogen group-containing compound containing water at the time of mixing and foaming is 0.7 to 1. .4 (isocyanate index (NCO INDEX) = 70 to 140) is preferable, and 0.7 to 1.2 (NCO INDEX = 70 to 120) is more preferable as a good range for foam durability and molding cycle. .

If the NCO INDEX is less than 70, the durability will decrease and the closed cell property will increase excessively, and if it is higher than 120, the molding cycle will be extended due to unreacted isocyanate remaining for a long time, and the foam foaming will be delayed during foaming due to the delay in polymerization. There is a risk of foam collapse, etc.

The method for producing flexible polyurethane foam includes a mixed solution of the polyol component (A), catalyst (B), foam stabilizer (C), blowing agent (D), crosslinking agent (E), and polyisocyanate component (F). A method for producing flexible polyurethane molded foam (hereinafter referred to as "flexible molded foam") can be used, which is characterized by injecting a foaming stock solution into a mold and then foaming and hardening.

The temperature of the mold when injecting the foaming stock solution into the mold is usually 30 to 80°C, preferably 45 to 65°C. If the mold temperature when injecting the foaming stock solution into the mold is less than 30°C, the reaction rate will decrease and the production cycle will be extended, while if it is higher than 80°C, the reaction between polyol and isocyanate will be delayed. If the reaction between water and isocyanate is excessively accelerated, the foam may collapse during foaming.

The curing time when foaming and curing the above-mentioned foaming stock solution is preferably 10 minutes or less, more preferably 7 minutes or less, considering the production cycle of general flexible molded foams.

When producing a flexible molded foam, the above-mentioned components can be mixed using a high-pressure foaming machine, a low-pressure foaming machine, etc., as in the case of ordinary flexible molded foams.

It is preferable that the isocyanate component and the polyol component are mixed immediately before foaming. Other components can be mixed in advance with the isocyanate component or polyol component to the extent that they do not affect the storage stability of the raw materials or changes in reactivity over time. These mixtures may be used immediately after mixing, or may be stored and then used in the required amount as appropriate. In the case of a foaming device that can simultaneously introduce more than two components into the mixing section, polyols, blowing agents, isocyanates, catalysts, foam stabilizers, additives, etc. can also be introduced individually into the mixing section.

Further, the mixing method may be either dynamic mixing in which mixing is performed in the mixing chamber of the machine head of the foaming machine, or static mixing in which mixing is performed within the liquid feeding pipe, or both may be used in combination. Mixing of a gaseous component such as a physical foaming agent and a liquid component is often performed by static mixing, and mixing of components that can be stably stored as a liquid is often performed by dynamic mixing. The foaming device used in the present invention is preferably a high-pressure foaming device that does not require solvent cleaning of the mixing section.

The liquid mixture obtained by such mixing is discharged into a mold, foamed and hardened, and then demolded. In order to perform the above-mentioned demolding smoothly, it is also suitable to apply a mold release agent to the mold in advance. As the mold release agent to be used, a mold release agent commonly used in the field of molding processing may be used.

Although the product after demolding can be used as is, it is preferable to destroy the cell membrane of the foam under compression or reduced pressure by a conventionally known method to stabilize the appearance and dimensions of the product thereafter.

By the above-described manufacturing method of flexible polyurethane foam, the apparent density is 30 kg/m ³ to 70 kg/m ³ , the 25% compression hardness of the skinned foam test piece is 100 to 350 N/314 cm ² , and the rebound modulus is 45 to 75%. , it is possible to obtain a flexible polyurethane foam with a wet heat compressive strain of less than 20%. Moreover, the flexible polyurethane foam has a hardness distribution in the foaming direction.

[Mechanism by which flexible polyurethane foam exhibits hardness distribution]
The mechanism by which the flexible polyurethane foam according to the present invention exhibits a hardness distribution will be explained. For example, a soft polyurethane foam used as a cushioning material is molded in a mold so that the lower mold side is the upper surface and the upper mold side is the lower surface. For this reason, the upper surface of the flexible polyurethane foam is formed first in the mold, and after volume expansion due to foaming, the lower surface is finally formed. When foam is formed on the upper surface side, carbohydrates associate with water, which delays the reaction between water and isocyanate and suppresses the formation of highly hard urea bonds. On the other hand, on the lower surface side from the core layer formed by high-temperature reaction, urea bonds are concentrated and generated, resulting in high hardness and a hardness distribution.

The flexible polyurethane foam manufactured as described above not only has excellent physical properties such as hardness and rebound modulus, but also has a hardness distribution in which the hardness increases from the top side to the bottom side, so it has excellent ride comfort. It becomes possible to provide it as a cushioning material.

EXAMPLES Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, unless otherwise specified, "part" and "%" in the text are based on mass.

[Preparation of polyol composition]
(Examples 1 to 15, Comparative Examples 1 to 6)
After purging the reactor equipped with a stirrer, cooling tube, nitrogen inlet tube, and thermometer with nitrogen, add 700 g of polyol 1, 300 g of polyol 3, 15 g of polyol 4, 15 g of crosslinking agent 1, 20 g of crosslinking agent 11, and catalyst. A polyol composition (P-1) was obtained by charging 8.0 g of Catalyst 1, 2.0 g of Catalyst 2, 10 g of Foam Stabilizer 1, and 36 g of water and stirring at 23° C. for 0.5 hour. Other polyol compositions (P-2 to P-21) were also prepared in the same manner as P-1.

Among the raw materials shown in Tables 1 to 4, the liquid temperature of the mixture (polyol composition) of all raw materials other than the polyisocyanate component was adjusted to 24°C to 26°C, and the liquid temperature of the polyisocyanate component was adjusted to 24°C to 26°C. did. A predetermined amount of the polyisocyanate component was added to the polyol composition, mixed for 7 seconds using a mixer (7000 revolutions per minute), and then poured into a mold to foam a flexible polyurethane foam. Thereafter, it was taken out from the mold and the physical properties of the obtained flexible polyurethane foam were measured. Note that the NCO Index in Tables 1 to 4 is the ratio of NCO groups to the number of active hydrogen atoms present in the formulation.

[Foaming conditions]
Mold temperature: 60-70℃
Mold shape: 300mm x 300mm x 100mm
Mold material: Aluminum Cure time: 5 minutes

[Raw materials used]
- Polyol 1: average number of functional groups = 3.0, hydroxyl value = 24 (mgKOH/g), terminal primaryization rate = 84%, oxyethylene unit = 14.6% by mass, total unsaturation degree 0.03 meq. /g of polyoxyethylene polyoxypropylene polyol, manufactured by Tosoh Corporation NEF-693
- Polyol 2: average number of functional groups = 3.0, hydroxyl value = 24 (mgKOH/g), terminal primaryization rate = 79%, oxyethylene unit = 14.0% by mass, total degree of unsaturation 0.19 meq. /g of polyoxyethylene polyoxypropylene polyol, NEF-728 manufactured by Tosoh Corporation
・Polyol 3: Polymer polyol with average functional group number = 3.0 and hydroxyl value = 24 (mgKOH/g), Excenol EL-923 manufactured by AGC
・Polyol 4: average number of functional groups = 3.0, hydroxyl value = 24 (mgKOH/g), polyether polyol with 70% by mass of oxyethylene units, NEF-729 manufactured by Tosoh Corporation
・Polyol 5: average number of functional groups = 4.0, hydroxyl value = 28 (mgKOH/g), polyoxyethylene polyoxypropylene polyol with oxyethylene units of 80% by mass, NEF-024 manufactured by Tosoh Corporation
・Polyol 6: average number of functional groups = 4.0, hydroxyl value = 28 (mgKOH/g), polyoxyethylene polyoxypropylene polyol with oxyethylene units of 90% by mass, NEF-730 manufactured by Tosoh Corporation
・Crosslinking agent 1: D-(+)-glucose (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., monosaccharide)
・Crosslinking agent 2: D-(-)-fructose (manufactured by Tokyo Kasei Kogyo Co., Ltd., monosaccharide)
・Crosslinking agent 3: D-(+)-sucrose (manufactured by Tokyo Kasei Kogyo Co., Ltd., disaccharide)
・Crosslinking agent 4: D-(+)-raffinose (manufactured by Tokyo Kasei Kogyo Co., Ltd., trisaccharide)
・Crosslinking agent 5: Glucose fructose liquid sugar (manufactured by Nippon Shokuhin Kogyo Co., Ltd., a mixture of monosaccharides and decasaccharides)
・Crosslinking agent 6: γ-cyclodextrin (manufactured by Tokyo Kasei Kogyo Co., Ltd., octasaccharide)
・Crosslinking agent 7: Maltose syrup (manufactured by Nihon Shokuhin Kogyo Co., Ltd., a mixture of monosaccharides and decasaccharides)
・Crosslinking agent 8: Purified glycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd.)
・Crosslinking agent 9: Trimethylolpropane (manufactured by Mitsubishi Gas Chemical Co., Ltd.)
・Crosslinking agent 10: Diethanolamine (manufactured by Mitsui Chemicals)
・Crosslinking agent 11: PEG200 (manufactured by Sanyo Chemical Industries, polyethylene glycol, number average molecular weight 200)
・Crosslinking agent 12: CHDM-D (1,4-cyclohexanedimethanol, manufactured by EASTMAN CHEMICAL, alicyclic glycol)
・Catalyst 1: 2-hydroxymethyltriethylenediamine (manufactured by Tosoh Corporation, product name: R-ZETA HD)
・Catalyst 2: N,N,N'-trimethyl-N'-hydroxyethyl-bisaminoethyl ether (manufactured by Tosoh Corporation, product name: TOYOCAT RX-10)
・Foam stabilizer 1: Silicone foam stabilizer (manufactured by Evonik, product name: B-8715LF2)
- Isocyanate 1: Polyphenylene polymethylene polyisocyanate with an MDI content of 85% by mass and an isomer content of 38% by mass (manufactured by Tosoh Corporation, trade name: CEF-550).

[Moldability evaluation]
In each table, the evaluation of formability "○" means that the urethane foam does not collapse after reaching its maximum height, or the generated urethane foam shrinks immediately after foaming or after curing, and is soft. It means that the polyurethane foam was molded, and an evaluation of "x" means that phenomena such as collapse and shrinkage occurred in the urethane foam.

[Apparent density]
It was determined by the method described in JIS K6400.

[25% compression hardness (25% ILD) of skinned specimen foam]
It was determined by method B described in JIS K6400.

[Repulsion modulus]
It was measured by the method described in JIS K6400.

[Moist heat compression strain]
It was measured by the method described in JIS K6400.

[Growth rate]
It was measured by the method described in JIS K6400.

[About hardness distribution in the foaming height direction of flexible polyurethane foam]
The samples for hardness distribution measurement in the present invention are made by cutting a flexible polyurethane foam with a thickness of 100 mm, which is molded so that the upper mold side is the lower surface and the lower mold side is the upper surface, every 45 mm from the end surface of the upper surface side toward the lower surface side. The foam has two layers: "Top side: 0 mm (top edge) to 45.0 mm, bottom side: 45.0 mm to 90.0 mm".
For each of the two layers of evaluation samples described above, first compress the evaluation sample until the stress applied to the pressure plate becomes 0.98N, and this position is set as the initial position of the pressure plate where the thickness of the evaluation sample is 100%. shall be. The pressure plate is a disk with a diameter of 200 mm. Next, the pressure plate is directed toward the evaluation sample and compressed to 25% of the thickness of the evaluation sample at a speed of 50 mm/min. Thereafter, the pressure plate is returned to the initial position at a speed of 50 mm/min. In the above process, when the evaluation sample was compressively deformed by 25%, the stress value applied to the evaluation sample was measured, and this value was defined as the 25% compression hardness.

Then, the hardness ratio of each evaluation sample was calculated when the average value of the 25% compression hardness of the evaluation samples of each of the two layers was set as 100. In other words, this hardness ratio means the hardness ratio of each evaluation sample to the average hardness in the foaming height direction.
If the hardness ratio of the upper foam is 50 to 85% when the average value of the 25% compression hardness of the evaluation samples of the two layers is 100, it can be said that the foam has a hardness distribution.

[Calculation method of urea bond ratio]
Perform FT-IR measurement on the evaluation sample of the above two layers, and divide the peak height derived from urea bond observed around wave number 1660 cm ^-1 by the peak height derived from urethane bond observed around wave number 1710 cm ^-1 . The urea bond ratio was calculated. In other words, the smaller the urea bond ratio is, the more suppressed the formation of urea bonds is, and the harder it is to develop hardness.

[Cell anisotropy (shape) of flexible polyurethane foam]
The sample for measuring cell anisotropy in the present invention was a flexible polyurethane foam molded with a thickness of 100 mm, and four layers of foam were cut out every 22.5 mm from the upper end surface toward the lower surface. : 0 mm (top edge) to 22.5 mm, 2nd layer: 22.5 mm to 45 mm, 3rd layer: 45 mm to 67.5 mm, 4th layer: 67.5 mm to 90 mm. It was divided into four layers from the first layer to the fourth layer. Each of the obtained layers was vertically divided into two equal parts, and an enlarged image of the central portion of the cross section (field of view: 3.2 mm x 3.2 mm) was obtained using a microscope. When the acquired image is viewed from bottom to top in the foaming direction, 30 foamed cells are randomly selected from the image and the cell length in the foaming direction and the cell length perpendicular to the foaming direction are calculated. It was measured. A value obtained by dividing the cell length in the foaming direction by the cell length perpendicular to the foaming direction was determined for each cell, and the average value of 30 cells was used as the evaluation value of cell anisotropy. The closer the anisotropy value is to 1, the more spherical the cell shape, the smaller the value, the more horizontally elongated with respect to the foaming direction, and the larger the value, the more vertically elongated with respect to the foaming direction. In this example, measurements were made using Example 1 and Comparative Example 3 as representative examples.

As shown in Comparative Examples 1 to 5 in Table 4, when carbohydrate (E-1) is not used as a crosslinking agent, the hardness distribution is extremely small or does not appear. In these cases, the urea bonding ratio on the upper surface side is higher and the urea bonding ratio on the lower surface side is lower than in the example. Furthermore, since there is no correlation between cell anisotropy and hardness distribution ratio, it cannot be said that hardness distribution is expressed by controlling cell anisotropy. As shown in Comparative Example 6, even when carbohydrate (E-1) is used as a crosslinking agent, if the amount used is too large compared to the specified amount, the molding stability of the foam decreases significantly, making it difficult to mold the foam. Can not do it. By comparing the above Examples and Comparative Examples, it is clear that in the present invention, a molded article having a hardness distribution that provides good sitting comfort when used as a cushioning material, and has favorable physical properties can be obtained. Therefore, the significance and remarkable excellence of the structure of the present invention can be understood.

Claims (18)

A polyol composition for molding flexible polyurethane foam, comprising a polyol component (A), a catalyst (B), a foam stabilizer (C), water (D), and a crosslinking agent (E),
A carbohydrate (E-1) is contained as the crosslinking agent (E), and the amount of the carbohydrate (E-1) added is 0.1 to 5% by mass relative to the polyol component (A),
The average number of sugar chains of the carbohydrate (E-1) is 1.0 or more and 9.0 or less,
A polyol composition for molding flexible polyurethane foam, characterized in that the amount of water (D) added is 3.0 to 10% by mass based on the polyol component (A). The polyol composition for molding flexible polyurethane foam according to claim 1, which is used for a cushion having a seating surface. A polyol composition for molding flexible polyurethane foam, comprising a polyol component (A), a catalyst (B), a foam stabilizer (C), water (D), and a crosslinking agent (E),
A carbohydrate (E-1) is contained as the crosslinking agent (E), and the amount of the carbohydrate (E-1) added is 0.1 to 5% by mass based on the polyol component (A),
The amount of water (D) added is 3.0 to 10% by mass based on the polyol component (A),
A polyol composition for molding a flexible polyurethane foam, which is used for a cushion having a seating surface. The polyol composition for molding flexible polyurethane foam according to claim 3, wherein the carbohydrate (E-1) has an average number of sugar chains of 1.0 or more and 9.0 or less. The polyol composition for molding flexible polyurethane foam according to any one of claims 1 to 4 , wherein the catalyst (B) contains two types of amine catalysts. The polyol composition for molding flexible polyurethane foam according to claim 5 , wherein at least one of the two types of amine catalysts is an amine catalyst having active hydrogen. The polyol component (A) contains a polyether polyol having a polyoxyalkylene chain consisting of a copolymer of oxyethylene and oxypropylene and having an oxyethylene unit of 60 to 90% by mass,
The number average molecular weight of the polyether polyol is 4,000 to 8,000,
The polyol for molding flexible polyurethane foam according to any one of claims 1 to 6 , wherein the amount of the polyether polyol added is 0.5 to 5% by mass based on the polyol component (A). Composition. The flexible polyurethane according to any one of claims 1 to 7 , wherein the crosslinking agent (E) further contains at least one cyclic glycol selected from the group consisting of alicyclic glycols and aromatic glycols. Polyol composition for foam molding. The polyol composition for molding flexible polyurethane foam according to any one of claims 1 to 8 , wherein the carbohydrate (E-1) contains at least one selected from monosaccharides to decasaccharides. A total unsaturation degree of 0.001 to 0.04 meq produced using at least one selected from a multimetal cyanide complex catalyst, a phosphazene catalyst, and an imino group-containing phosphazenium salt as a catalyst in the polyol component (A). ．． The polyol composition for molding flexible polyurethane foam according to any one of claims 1 to 9 , characterized in that it contains polyoxyalkylene polyol (A-1) of /g. A flexible polyurethane foam molding composition comprising the flexible polyurethane foam molding polyol composition according to any one of claims 1 to 10 and a polyisocyanate component (F), wherein the polyisocyanate component (F) is Contains diphenylmethane diisocyanate in a range of 50 to 85% by mass, and the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate contained in the diphenylmethane diisocyanate is 10 to 50% by mass with respect to the total amount of diphenylmethane diisocyanate. A flexible polyurethane foam molding composition characterized by: A flexible polyurethane foam obtained by reaction foaming the flexible polyurethane foam molding composition according to claim 11 . Two layers of soft polyurethane foam were cut out at 45% thickness intervals from the upper end to the lower end, which were molded so that the upper mold side was the lower surface and the lower mold side was the upper surface. The flexible polyurethane foam according to claim 12 , wherein the hardness ratio of the upper foam is 50 to 85% when the average value of the 25% compression hardness of the foam is 100. A flexible polyurethane foam obtained by reaction-foaming a flexible polyurethane foam-molding composition containing a flexible polyurethane foam-molding polyol composition and a polyisocyanate component (F),
The polyol composition for molding flexible polyurethane foam includes a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a crosslinking agent (E),
A carbohydrate (E-1) is contained as the crosslinking agent (E), and the amount of the carbohydrate (E-1) added is 0.1 to 5% by mass relative to the polyol component (A),
The average number of sugar chains of the carbohydrate (E-1) is 1.0 or more and 9.0 or less,
Two layers of soft polyurethane foam were cut out at 45% thickness intervals from the upper end to the lower end, which were molded so that the upper mold side was the lower surface and the lower mold side was the upper surface. The hardness ratio of the upper foam is 50 to 85% when the average value of the 25% compression hardness of the foam is 100,
A flexible polyurethane foam characterized by a rebound modulus of 45 to 75%. A flexible polyurethane foam obtained by reaction-foaming a flexible polyurethane foam-molding composition containing a flexible polyurethane foam-molding polyol composition and a polyisocyanate component (F),
The polyol composition for molding flexible polyurethane foam includes a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a crosslinking agent (E),
A carbohydrate (E-1) is contained as the crosslinking agent (E), and the amount of the carbohydrate (E-1) added is 0.1 to 5% by mass relative to the polyol component (A),
Two layers of soft polyurethane foam were cut out at 45% thickness intervals from the upper end to the lower end, which were molded so that the upper mold side was the lower surface and the lower mold side was the upper surface. The hardness ratio of the upper foam is 50 to 85% when the average value of the 25% compression hardness of the foam is 100,
The rebound modulus is 45 to 75%,
Apparent density is 30-70kg/m ³ A flexible polyurethane foam characterized by: A claim characterized in that the apparent density is 30 to 70 kg/m ³ , the 25% compression hardness of the skinned foam test piece is 100 to 350 N/314 cm ² , and the elongation is 100% or more The flexible polyurethane foam according to any one of Items 12 to 15 . The flexible polyurethane foam according to any one of claims 12 to 16 , having a rebound modulus of 45 to 75% and a wet heat compressive strain of less than 20%. The flexible polyurethane foam according to any one of claims 12 to 17 , which is a cushion having a seating surface.