Polyurethane foam

Abstract

Polyurethane foam, which is obtained by foaming a mixture comprising a polyol and a polyisocyanate, wherein the polyol comprises: a polycarbonate diol having a polyester structure; and a polycarbonate diol obtained by developing a polymerization reaction using 1,5-pentanediol and 1,6-hexanediol, where the polyurethane foam has a density of 0.1 to 0.4 g / cm³ 3 exhibits wherein a mixing ratio between the polycarbonate diol having the polyester structure and the polycarbonate diol obtained by developing the polymerization reaction using 1,5-pentanediol and 1,6-hexanediol is from 10:90 to 90:10, and wherein the mixture further comprises water and contains 1 to 5 parts by mass of water, based on 100 parts by mass of polyol.

Description

Technical field

[0001] The present invention relates to a polyurethane foam obtained by foaming a mixture containing a polyol and a polyisocyanate. State of the art

[0002] A run-flat tire system is known as a technique for enabling a vehicle to continue driving in situations such as a puncture. In this system, a core (support body) separate from the tire is arranged in a cavity between the tire and the rim to support a section of the tire tread in the event of a puncture. For example, a support body made of polyurethane foam is known (Patent Document 1). Patent Document 2 relates to a polyurethane foam obtained by foaming a mixture comprising a polyol and an isocyanate. List of oppositions patent literature Patent Document 1: JP 2004-291725 A Patent document 1: DE 10 2015 014 864 A1 Brief description of the invention: Technical problem

[0003] In the aforementioned run-flat tire system, the supporting structure must possess sufficient mechanical strength to bear the vehicle's load. Conversely, it is also necessary for the supporting structure to be lightweight.

[0004] One object of the present invention is to provide a polyurethane foam that has excellent mechanical strength while being lightweight. Solution to the problem

[0005] One aspect of the present invention is a polyurethane foam obtained by foaming a mixture comprising a polyol and a polyisocyanate, wherein the polyol includes: a polycarbonate diol having a polyester structure; and a polycarbonate diol obtained by developing a polymerization reaction using 1,5-pentanediol and 1,6-hexanediol, where the polyurethane foam has a density of 0.1 to 0.4 g / cm³ 3 exhibits a mixing ratio between the polycarbonate diol having the polyester structure and the polycarbonate diol obtained by developing the polymerization reaction using the 1,5-pentanediol and the 1,6-hexanediol of 10:90 to 90:10, and wherein the mixture further comprises water and contains 1 to 5 parts by mass of water, based on 100 parts by mass of polyol.

[0006] The mixture of polycarbonate diol obtained by developing the polymerization reaction using 1,5-pentanediol and 1,6-hexanediol is preferably equal to or greater than the mixture of polycarbonate diol having the polyester structure.

[0007] The polyol preferably includes, in addition to the polycarbonate diol having the polyester structure and the polycarbonate diol obtained by developing the polymerization reaction using 1,5-pentanediol and 1,6-hexanediol, a further polyol.

[0008] The flexural strength at a stress of 5% according to JIS K7221-2 is preferably 50 N / cm². 2 or more and the bending force is preferably 400 N / cm 2 or more.

[0009] The compressive strength at a stress of 10% according to JIS K7220 is preferably 30 N / cm². 2 or more.

[0010] The compression set according to JIS K6767 is preferably 10% or less.

[0011] The mixture preferably further includes at least one arbitrarily selected from the group consisting of a filler, a fiber, an adhesion promoter, a surfactant and an anti-aging agent. Advantageous effects of the invention

[0012] From the above perspective, a polyurethane foam with excellent mechanical strength is obtained, which is also lightweight. Description of embodiments

[0013] A polyurethane foam according to the present embodiment is described below. Polyurethane foam

[0014] Polyurethane foam is obtained by foaming a mixture containing a polyol and a polyisocyanate.

[0015] The polyol is a component with two or more hydroxyl groups in one molecule. In the present embodiment, the polyol contains two different types of polycarbonate diols: (1) a polycarbonate diol having a polyester structure (hereinafter also referred to as polycarbonate diol 1); and (2) a polycarbonate diol obtained by developing a polymerization reaction using 1,5-pentanediol and 1,6-hexanediol (hereinafter also referred to as polycarbonate diol 2). The mixture containing such polyols is foamed to obtain a polyurethane foam that has a low density with excellent flexural strength, bending force, compressive strength, and excellent compression set.Note that in this patent specification, flexural strength refers to a bending force at a stress of 5%, measured according to JIS K7221-2, and the bending force refers to a bending force (maximum bending force) in the event of failure due to a further stress of more than 5%. Furthermore, in this patent specification, compressive strength refers to a compressive strength at a stress of 10% (10% deformation compressive strength), measured according to JIS K7220.

[0016] The compression set refers to a compression set measured according to JIS K6767.

[0017] If polycarbonate diol 2 of the two aforementioned types of polycarbonate diols is not included, at least one of the following properties of the polyurethane foam will be unsuitable: flexural strength, bending force, compressive strength, or compression set. In particular, the mechanical strength (hereinafter also referred to simply as "strength") of the polyurethane foam will be insufficient. Furthermore, if polycarbonate diol 1 of the two aforementioned types of polycarbonate diols is not included, the polyurethane foam will meet a predetermined flexural strength but will become brittle due to the low bending force. Additionally, the compressive strength of the polyurethane foam will be unsuitable.

[0018] Polycarbonate diol 1 is a polycarbonate diol exhibiting a polyester structure. A polyester structure generally refers to a structure obtained through a dehydrogenation-condensation reaction between a diol and a dicarboxylic acid. Polycarbonate diol 1 has a structure represented by the following general formula (1) and a terminal hydroxyl group. -[-RO(CO)O-]1- (1)

[0019] Among the repeating units of the structure of general formula (1) included in polycarbonate diol 1, each R represents an independent alkylene group having 1 to 12 carbon atoms, and the structure of general formula (1) partially includes the polyester structure. 1 is an integer from 1 to 20.

[0020] The number-averaged molecular weight of the polycarbonate diol 1 is preferably from 300 to 3000.

[0021] For the polycarbonate diol 1, for example, NIPPOLLAN 981, 980R, and 982R from Tosoh Corporation can be used individually, or two or more of them can be used in combination. NIPPOLLAN 981 has a number-average molecular weight of 1000 in the general formula (1). NIPPOLLAN 980R and 982R have a number-average molecular weight of 2000.

[0022] Polycarbonate diol 2 is a polycarbonate diol obtained by developing a polymerization reaction using 1,5-pentanediol and 1,6-hexanediol and a carbonate compound as raw materials. In particular, polycarbonate diol 2 has a structure represented by the following general formula (2) and a terminal hydroxyl group. -[-R 1 -O(CO)O-] m -[-R 2 -O(CO)O-] n - (2)

[0023] In the general formula (2) R 1 and R 2They are different from each other and are either (CH2)5 or (CH2)6. m and n are each an integer from 2 to 12.

[0024] The number-averaged molecular weight of the polycarbonate diol 2 is preferably from 300 to 3000.

[0025] For polycarbonate diol 2, for example, DURANOL T5650E, T5650J, T5651, and T5652 from Asahi Kasei Corp. can be used individually, or two or more of them can be used in combination. In DURANOL T5650E, in general formula (2), m and n each have approximately 2 and a number-average molecular weight of 500. In DURANOL T5650J, in general formula (2), m and n each have approximately 3 and a number-average molecular weight of 800. In DURANOL T5651, in general formula (2), m and n each have approximately 4 and a number-average molecular weight of 1000. In DURANOL T5652, in general formula (2), m and n each have approximately 8 and a number-average molecular weight of 2000.

[0026] From the perspective of improving the mechanical strength of the polyurethane foam, the amount (mass) of polycarbonate diol 2 is preferably equal to or greater than the amount (mass) of polycarbonate diol 1, and more preferably greater than the amount (mass) of polycarbonate diol 1. In this case, the mixing ratio between polycarbonate diol 1 and polycarbonate diol 2 is preferably 1:1.5 to 1:5, and more preferably 1:2 to 1:4, based on the mass ratio.

[0027] The polyol may contain other polyols besides the polycarbonate diols 1 and 2 mentioned above. For example, other polycarbonate polyols besides polycarbonate diols 1 and 2, polyether polyols, polyester polyols, and other polyols may be used individually, or two or more of them may be used in combination.

[0028] Polycarbonate polyols, different from the polycarbonate diols 1, 2, are prepared by reactions such as a methanol elimination condensation reaction between a polyol and a dimethyl carbonate, a phenol elimination condensation reaction between a polyol and a diphenyl carbonate, or an ethylene glycol elimination condensation reaction between a polyol and an ethylene carbonate. Examples of polyols used in these reactions include: various saturated or unsaturated glycols, such as 1,6-hexanediol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, octanediol, 1,4-butynediol, dipropylene glycol, tripropylene glycol, and polytetramethylene ether glycol; and alicyclic glycols, such as 1,4-cyclohexanediglycol and 1,4-cyclohexanedimethanol.

[0029] Examples of polyether polyols include: polyols obtained by adding at least one of any ethylene oxides, propylene oxides, butylene oxides, styrene oxide and the like to at least one type of polyhydric alcohol selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerol, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol, 1,3-butanediol, 1,4-butanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane and pentaerythritol; and polyoxytetramethylene oxides.

[0030] Examples of polyester polyols include: condensation polymers of one or two or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerol, 1,1,1-trimethylolpropane, and one or two or more of glutaric acid, adipic acid, pimelic acid, corkic acid, sebacic acid, terephthalic acid, isophthalic acid, dimeric acid and other low molecular weight carboxylic acids and oligomeric acids; and ring-opened polymers such as propiolactone and valerolactone.

[0031] Examples of other polyols include polymer polyols; polybutadiene polyols; hardened polybutadiene polyols; acrylic polyols; and low molecular weight polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, hexanediol, polyethylene glycol laurylamines (e.g. N,N-bis(2-hydroxyethyl)laurylamine), polypropylene glycol laurylamines (e.g. N,N-bis(2-methyl-2-hydroxyethyl)laurylamine), polyethylene glycoloctylamines (e.g. N,N-bis(2-hydroxyethyl)octylamine), polypropylene glycoloctylamines (e.g. N,N-bis(2-methyl-2-hydroxyethyl)octylamine), polyethylene glycol stearylamines (e.g. N,N-bis(2-hydroxyethyl) stearylamine), polypropylene glycol stearylamines (e.g. N,N-bis(2-methyl-2-hydroxyethyl) stearylamine) and Tris-(2-hydroxyethyl)isocyanurate.

[0032] The amount of other polyols that may be contained in the polyol besides the polycarbonate diols 1, 2, as mentioned above, is preferably 1 to 15 parts by mass based on 100 parts by mass of the total amount of polycarbonate diols 1, 2.

[0033] The polyisocyanate is not subject to any special restrictions as long as it has two or more isocyanate groups in one molecule and is a known polyisocyanate. Examples of known polyisocyanates include: diisocyanate compounds, e.g., aromatic polyisocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolide diisocyanate (TODI), and naphthalene diisocyanate (NDI); aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, and norbornane diisocyanate methyl (NBDI); and alicyclic polyisocyanates such as transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6XDI (hardened XDI), H12MDI (hardened MDI), and H6TDI (hardened TDI); and polyisocyanate compounds such as polymethylenepolyphenylene polyisocyanate. Carbodiimide-modified polyisocyanates of these isocyanate compounds;Isocyanurate-modified polyisocyanates of these isocyanate compounds; and urethane prepolymers obtained by reacting these isocyanate compounds with the polyol compounds mentioned above as examples, these compounds being usable alone or in combination with each other.

[0034] The polyisocyanate is preferably a polymer containing an isocyanate group in the repeating unit, in particular comprising one or more repeating units, each with an isocyanate group; and one end with an isocyanate group, i.e., preferably a polymer polyisocyanate. Among the known polyisocyanates mentioned above, polymethylene polyphenylene polyisocyanates are preferably used.

[0035] Preferably, the equivalent ratio of isocyanate groups in the polyisocyanate to hydroxyl groups in the polyol is 0.8 to 1.2 in the aforementioned mixture. If the equivalent ratio is below 0.8, the mechanical strength of the polyurethane foam may be unsuitable. If the equivalent ratio exceeds 1.2, the polyurethane foam may become brittle.

[0036] The mixture also contains 1 to 5 parts water by mass per 100 parts by mass of polyol. The water content in the aforementioned range appropriately accelerates the foaming reaction between the water and the polyisocyanate, thus facilitating the adjustment of the polyurethane foam density to 0.1 to 0.4 g / cm³. 3 The amount of water mixed is preferably 2 to 4 parts by mass in relation to 100 parts by mass of the polyol.

[0037] The aforementioned mixture preferably includes, in addition to the polyol, the polyisocyanate, and water, at least one selected from the group consisting of fillers, fibers, adhesion promoters, surfactants, and antioxidants, to the extent that the objective of the present invention is not compromised. Furthermore, the mixture may also include a catalyst, a foam stabilizer, and the like.

[0038] The aforementioned mixture is produced, for example, as a main component consisting of the polyisocyanate and a hardener that includes all components except the polyisocyanate.

[0039] The density of the polyurethane foam according to the present embodiment is from 0.1 to 0.4 g / cm³. 3The density in this range is obtained by foaming the mixture described above to produce a polyurethane foam. The density in the aforementioned range is lower than that of known polyurethane foams, and the polyurethane foam according to the present embodiment is lightweight.

[0040] Since, in contrast, the polyurethane foam according to the present embodiment is produced using the aforementioned mixture, the flexural strength is preferably 50 N / cm². 2 or more and a bending force of 400 N / cm 2 or more. Since the polyurethane foam according to the present embodiment is produced using the aforementioned mixture, the compressive strength is also preferably 30 N / cm². 2or more. Since the polyurethane foam according to the present embodiment is produced using the aforementioned mixture, the compression set is also preferably no greater than 10%. In particular, the polyurethane foam according to the present embodiment exhibits excellent mechanical strength.

[0041] As described above, the polyurethane foam according to the present embodiment exhibits excellent mechanical strength while being lightweight and can be used in various applications. For example, if the polyurethane foam is used for a support body in a run-flat tire system, a lightweight support body with excellent run-flat durability can be obtained. "Run-flat durability" refers to a property that is evaluated by the number of run-flat kilometers driven.

[0042] The density of the polyurethane foam is preferably 0.15 to 0.3 g / cm³. 3 .

[0043] The flexural strength of the polyurethane foam is preferably 60 N / cm². 2 or more. The upper limit of the bending strength, on the other hand, is, for example, 90 N / cm². 2 .

[0044] The flexural strength of the polyurethane foam is preferably 500 N / cm². 2 or more. The upper limit of the bending force, however, is, for example, 700 N / cm. 2 .

[0045] The compressive strength of the polyurethane foam is preferably 35 N / cm². 2 or more. The upper limit of compressive strength, on the other hand, is, for example, 60 N / cm². 2 .

[0046] The compression set of the polyurethane foam is preferably 8% or less. The lower limit of the compression set, however, is, for example, 5%.

[0047] In the case where the polyurethane foam is used with a compression set of 10% or less than the aforementioned support body, the extent of deformation of the polyurethane mold, which is repeatedly subjected to a load at high speed during emergency running, is low and excellent emergency running durability is achieved.

[0048] The polyurethane foam according to the present embodiment can, as described above, be used in a suitable manner as a support body for a run-flat tire system. The support body is, in particular, divided into a plurality of segments in an annular shape or in a tire circumferential direction, which are arranged in a cavity between a tire and a rim. The support body is, for example, attached to the surface on the inside in a tire radial direction of the tread section of the tire (the inner surface of the tire in contact with the cavity). Alternatively, the support body is, for example, attached to the surface on the outside of the rim in the radial direction in contact with the cavity.The support body can be attached to the tire or rim using an adhesive, a pressure-sensitive adhesive, a cushioning material, a foam molded body, other mechanical fasteners, or the like.

[0049] Furthermore, the polyurethane foam according to the present embodiment exhibits excellent mechanical strength while being lightweight as described above; it can be used in various fields, such as, in addition to the support body of the run-flat tire system, in ships, vehicles, factories, thermal insulation devices, buildings and structures, household appliances and furniture, and can be used in these fields as reinforcement material, heat-insulating material, core material, buoyancy material, heat-storing element, cover, lid, vibration damper, packaging material, molding material and the like.

[0050] The shape of polyurethane foam is not subject to any special restrictions and can take on various forms, such as a ring shape, a block shape, a rod shape, a plate shape and a sheet shape.

[0051] Polyurethane foam can be used, for example, in conjunction with a structure made of rubber, plastic, metal, or similar materials. Specifically, polyurethane foam is used inside a structure such as a hollow, tubular, or box-shaped structure; between multiple structures such as plate-like structures; or attached to the surface of a structure. The material and shape of the structure are selected according to the application, with the aim of achieving both weight reduction and mechanical strength. Method for producing polyurethane foam

[0052] The polyurethane foam according to the present embodiment is produced using a mixture containing a polyol and a polyisocyanate. The mixture described herein is composed in the same manner as the mixture mentioned above. In particular, the main agent, the hardener, and water forming the mixture are combined to react and polymerize the polyisocyanate and the polyol, react the polyisocyanate and the water, and then generate carbon dioxide gas (foaming) in the polymer, thus producing a polyurethane foam.

[0053] The polyurethane foam can be pre-shaped into a predetermined form using a mold inside the structure. Alternatively, the polyurethane foam can be produced by foaming the mixture inside the structure, using the structure itself as a mold. Attempt

[0054] To investigate the effects of embodiments of the present invention, polyurethane foams are produced and their density, flexural strength, bending force, compressive strength and compression set are measured.

[0055] The mixtures used to produce the polyurethane foams are manufactured by mixing raw materials according to the mixing quantities specified in Table 1. [Table 1] Examples Comparative example 1 2 3 4 1 2 3 4 5 Polycarbonate diol 1 80 50 20 45 50 100 Polycarbonate diol 2 20 50 80 45 50 100 Polycarbonate diol 3 100 Polytetramethylene ether glycol 10 100 Amine compound 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 Foam stabilizer 1,2 1,2 1,2 1,2 1,2 1,2 1,2 1,2 1,2 Polymer isocyanate compound 1 100 100 100 100 100 100 100 100 40 Polymer isocyanate compound 2 40 Water 4 3 2 3 10 3 3 3 10 Density (g / cm³) 3 ) 0,18 0,21 0,25 0,20 0,08 0,15 0,22 0,23 0,15 Flexural strength (N / cm) 2 ) 68 75 81 71 21 33 45 51 83 Bending force (N / cm) 2 ) 582 613 677 591 177 258 390 315 681 Compressive strength (N / cm²) 2 ) 34 51 56 42 13 21 24 38 51 Compression set (%) 8 6 8 9 29 21 11 13 14

[0056] The raw materials shown in Table 1 are supplied by the following materials. The quantities of raw materials are given in parts by mass. • Polycarbonate diol 1: NIPPOLLAN 982R, from Tosoh Corporation • Polycarbonate diol 2: DURANOL T5650J, from Asahi Kasei Corp. • Polycarbonate diol 3: DURANOL T5651, from Asahi Kasei Corp. • Polytetramethylene ether glycol: PTMG1000, from Mitsubishi Chemical Corporation • Amine compound: 1,4-Azabicyclo[2.2.2]octane, from Tokyo Chemical Industry Co., Ltd. • Foam stabilizer: FZ3703 (silicone oil), manufactured by Dow Corning Toray Co., Ltd. • Polymer isocyanate compound 1: SUMIDULE 44V20 (Polymethylenepolyphenylpolyisocyanate), from Sumika Bayer Urethane Co., Ltd., NCO group content = 31% • Polymer isocyanate compound 2: SUMIDULE 44V10 (polymethylenepolyphenylpolyisocyanate), from Sumika Bayer Urethane Co., Ltd., NCO group content = 31%. Although not shown in the table, in comparative example 5, 0.5 parts by mass of tin octylate (NEOSTANN U-28, available from Nitto Kasei Co., Ltd.) are added as a catalyst.

[0057] The prepared mixtures are stirred for 1 minute at room temperature (25 °C), immediately poured into a mold of a predetermined shape, and foamed. Foaming ceases approximately 30 seconds after it begins. The reactants are then left to stand for 24 hours to complete the foaming and polymerization reactions, thus obtaining the samples according to Examples 1 to 4 and Comparative Examples 1 to 5. The properties of the prepared samples are measured as follows. The results are shown in Table 1. density

[0058] The measurement is performed according to JIS K7222. This covers the range from 0.1 to 0.4 g / cm³. 3 Rated as successful weight loss. Flexural strength, bending force

[0059] According to JIS K7221-2, bending tests are performed under the following temperature conditions: 23 °C, humidity: 50%, and wedge movement speed: 20 mm / min. The bending force of the specimen is measured at a stress of 5%. Subsequently, the specimen is subjected to a stress greater than 5%, and the flexural tensile strength of the specimen is measured. compressive strength

[0060] According to JIS K7220, compressive strength tests are carried out under the following temperature conditions: 23 °C, humidity: 50 % and movement speed of the moving plate: 20 mm / min, and the compressive strength of the specimen is measured at a stress of 10 %. Compression deformation residue

[0061] The compression set is measured according to JIS K6767. The measurement is carried out for 22 hours at 23 °C. From the above results, a value of 50 N / cm is determined. 2 or more flexural strength, 400 N / cm 2or more bending force, 30 N / cm 2 or higher compressive strength and 10% or less compression set in terms of mechanical strength are rated as excellent.

[0062] By comparing Examples 1 to 4 with Comparative Examples 1 to 5, it is determined that the polyurethane foams produced using the mixtures containing both polycarbonate diols 1, 2 as polyol exhibit excellent mechanical strength while being lightweight.

Claims

[1] Polyurethane foam obtained by foaming a mixture comprising a polyol and a polyisocyanate, wherein the polyol comprises: a polycarbonate diol having a polyester structure; and a polycarbonate diol obtained by developing a polymerization reaction using 1,5-pentanediol and 1,6-hexanediol, where the polyurethane foam has a density of 0.1 to 0.4 g / cm³ 3 exhibits wherein a mixing ratio between the polycarbonate diol having the polyester structure and the polycarbonate diol obtained by developing the polymerization reaction using 1,5-pentanediol and 1,6-hexanediol is from 10:90 to 90:10, and wherein the mixture further comprises water and contains 1 to 5 parts by mass of water, based on 100 parts by mass of polyol. [2] Polyurethane foam according to claim 1, wherein a mixture of the polycarbonate diol obtained by developing the polymerization reaction using the 1,5-pentanediol and the 1,6-hexanediol is equal to or greater than a mixture of the polycarbonate diol having the polyester structure. [3] Polyurethane foam according to claim 1 or 2, wherein the polyol, in addition to the polycarbonate diol having the polyester structure and the polycarbonate diol obtained by developing the polymerization reaction using the 1,5-pentanediol and the 1,6-hexanediol, further comprises another polyol. [4] Polyurethane foam according to any one of claims 1 to 3, wherein the flexural strength at a stress of 5 % according to JIS K7221-2 is 50 N / cm 2 or more and the bending force is 400 N / cm 2 or more. [5] Polyurethane foam according to any one of claims 1 to 4, wherein the compressive strength at a stress of 10 % according to JIS K7220 is 30 N / cm². 2 or more. [6] Polyurethane foam according to any one of claims 1 to 5, wherein the compression set according to JIS K6767 is 10% or less. [7] Polyurethane foam according to any one of claims 1 to 6, wherein the mixture further comprises at least one selected from the group consisting of a filler, a fiber, an adhesion promoter, a surfactant and an anti-aging agent.