Polyurethane foam, and adhesive tape substrate including the polyurethane foam

Abstract

To provide a technique for a polyurethane foam that can contribute to environmental conservation.SOLUTION: The present technique is directed to a polyurethane foam derived from a composition containing a polyol and an isocyanate, where the polyol contains a polyetherpolyol with a weight average molecular weight of 1200 or more and a polyol with a molecular weight of 300 or less. The polyurethane foam according to the present technique may have a silicone content of 0.25 ppm or less as measured in accordance with VDA278-based methods.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present technology relates to a polyurethane foam and a pressure-sensitive adhesive tape substrate using the polyurethane foam. [Background technology]

[0002] Polyurethane foam is used in furniture such as sofas and chairs, bedding such as mattresses and pillows, underwear, etc. They are widely used in a variety of fields, from clothing, daily necessities such as dish sponges and cleaning sponges, vehicle and aircraft interior products such as car seats, electronic devices such as mobile phones, cameras, and televisions, electrical appliances such as home appliances, toys, and miscellaneous goods. Various developments are being carried out to improve quality and add new functions according to each field and purpose.

[0003] For example, Patent Document 1 discloses a double-sided adhesive tape having a foam substrate and a first adhesive layer and a second adhesive layer on both sides of the foam substrate, wherein a first resin layer and a second resin layer having a tensile stress at break of 4 MPa or more are provided between the foam substrate and the first adhesive layer, and between the foam substrate and the second adhesive layer, respectively, and at least one of the first resin layer and the second resin layer has a tensile modulus of elasticity of 50 MPa or less. The double-sided adhesive tape also discloses that a polyurethane foam can be used as the foam substrate.

[0004] In addition, in recent years, in order to contribute to environmental consideration and the formation of a sustainable society, a technology for producing a foam using biomass resources has also been proposed. For example, Patent Document 2 discloses a polyurethane resin molded product comprising: a polyurethane resin (C) having a biological origin ratio of 36% by weight or more, which is obtained by reacting a polyol component (Z) for producing a polyurethane resin, which is at least one selected from the group consisting of an alkylene oxide adduct (a1) of biological glycerin, an alkylene oxide adduct (a2) of sucrose, and an alkylene oxide adduct (a3) ​​of sorbitol, and which contains a biological polyol (a) having a number average molecular weight of 200 to 1200, castor oil (k), and a biological carbonate (b), and which is obtained by reacting a polyol component (Z) for producing a polyurethane resin, which has a biological origin ratio of 50% by weight or more in its total weight, with a polyisocyanate component (Q).

[0005] Patent Document 3 discloses a technology for obtaining a flexible polyurethane foam having a plant-based content of more than 10% and having effects equivalent to those of conventional products, by using a polyether polyol obtained by dehydration condensation of 1,3-propanediol obtained by fermenting starch as 1,3-propanediol, which is one of the raw materials for polyether polyol, and an alcohol having a valence of three or more, in a ratio of 90 to 99.3 mol % of 1,3-propanediol relative to the total of 100 mol % of the above. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 059791 [Patent Document 2] JP 2013-189627 A [Patent Document 3] JP 2014-162813 A Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, various developments are being promoted to contribute to environmental consideration and the formation of a sustainable society, but there is still a lot of development to be done. For example, foam stabilizers are often required to produce suitable polyurethane foams, but some foam stabilizers contain volatile organic compounds (VOCs) such as silicone, making it difficult to produce polyurethane foams while being environmentally friendly.

[0008] Therefore, the main objective of this technology is to provide polyurethane foam technology that can contribute to environmental conservation. [Means for solving the problem]

[0009] In the present technology, first, a polyurethane foam obtained from a composition containing a polyol and an isocyanate, The polyol contains a polyether polyol having a weight average molecular weight of 1,200 or more and a polyol having a molecular weight of 300 or less, thereby providing a polyurethane foam. The polyurethane foam according to the present technology can have a silicone content of 0.25 ppm or less, as measured in accordance with a method based on VDA278. As the polyether polyol having a weight average molecular weight of 1,200 or more contained in the polyurethane foam according to the present technology, a biomass-derived polyether polyol can be used. The polyurethane foam related to this technology has a density of 100 kg / m 3 It can be more than that. The polyol having a molecular weight of 300 or less contained in the polyurethane foam according to the present technology may contain a polyol having two functional groups and a polyol having three functional groups.

[0010] Next, the present technology provides an adhesive tape substrate using the polyurethane foam according to the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A preferred embodiment for carrying out the present technology will be described below. The embodiments described below are examples of typical embodiments of the present technology, and any of the embodiments can be combined. In addition, the scope of the present technology is not narrowly interpreted by these.

[0012] 1. Composition for producing polyurethane foam The polyurethane foam according to the present technology is produced using a composition containing a polyol and an isocyanate. The composition used for producing the polyurethane foam according to the present technology may also contain a filler, a catalyst, an antioxidant, a moisture absorbent, a foam stabilizer, a blowing agent, etc., as necessary.

[0013] The polyurethane foam according to the present technology is preferably produced by a mechanical flossing method, as described below. That is, the composition used for producing the polyurethane foam according to the present technology can be suitably used as a composition for mechanical flossing. Each component will be described in detail below.

[0014] (1) Polyol The present technology is characterized by using a polyether polyol having a weight average molecular weight of 1,200 or more and a polyol having a molecular weight of 300 or less as the polyol.

[0015] (1-1) Polyether polyol with a weight average molecular weight of 1,200 or more Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytrimethylene ether glycol, polytetramethylene ether glycol, etc., which are obtained by polymerizing cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran, respectively, and copolyethers thereof. Also, the above-mentioned cyclic ethers can be polymerized using polyhydric alcohols such as glycerin and trimethylolethane. In the present technology, polyether polyols having a weight average molecular weight of 1200 or more can be selected from these and used.

[0016] The lower limit of the weight average molecular weight of the polyether polyol used in the present technology is 1200 or more, so that the action and effect of the present technology can be exhibited, but is preferably 1500 or more, more preferably 2000 or more, and even more preferably 2200 or more. In addition, the upper limit of the weight average molecular weight of the polyether polyol having a weight average molecular weight of 1200 or more is not limited as long as the action and effect of the present technology is not impaired, but is preferably 12000 or less, more preferably 7000 or less, and even more preferably 5000 or less.

[0017] The amount of polyether polyol having a weight average molecular weight of 1200 or more used in the present technology can be freely set as long as it does not impair the action or effect of the present technology. In the present technology, the lower limit of the polyether polyol having a weight average molecular weight of 1200 or more in the composition is, for example, 50 parts by mass or more, preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more in 100 parts by mass of polyol. By setting the lower limit of the polyether polyol having a weight average molecular weight of 1200 or more in 100 parts by mass of polyol within this range, the properties of the soft segment part of the urethane resin skeleton are dominant, and flexibility can be maintained.

[0018] The upper limit of the polyether polyol having a weight average molecular weight of 1200 or more in the composition can be set to, for example, 99.9 parts by mass or less, 99.8 parts by mass or less, 99.7 parts by mass or less, or 99.6 parts by mass or less per 100 parts by mass of polyol.

[0019] (1-2) Polyol with molecular weight of 300 or less This technology makes it possible to produce high-quality polyurethane foam by using a polyol with a molecular weight of 300 or less. When using a polymer as a polyol with a molecular weight of 300 or less in this technology, the "molecular weight" is replaced with the "weight average molecular weight."

[0020] The lower limit of the molecular weight of the polyol having a molecular weight of 300 or less used in the present technology is not limited as long as it does not impair the action and effect of the present technology, but is preferably 48 or more, more preferably 60 or more, and even more preferably 70 or more. The upper limit of the molecular weight of the polyol is, for example, 300 or less, 250 or less, 200 or less, or 150 or less.

[0021] Examples of polyols having a molecular weight of 300 or less include diols such as ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol (trimethylene glycol), 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, and diethylene glycol; 1,2,3-propanetriol (glycerin), 1,2,4-butanetriol, 1,2,3-butanetriol, 1,2,3-pentanetriol, 1,2,5-pentanetriol, Examples of the polyhydric alcohol include triols such as 1,3,5-pentanetriol, 2,3,4-pentanetriol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,3,5-hexanetriol, 1,2,5-pentanetriol, 1,2,3-pentanetriol, 2,3,4-pentanetriol, 1,3,5-pentanetriol, 1,2,8-octanetriol, 1,2,3-octanetriol, 1,2,9-nonanetriol, and 1,2,3-nonanetriol; and tetraols such as 1,2,3,4-butanetetraol, 1,2,3,5-pentanetetraol, and 1,2,4,5-hexanetetraol.

[0022] Furthermore, so long as the weight average molecular weight is 300 or less, for example, polymers such as polyester polyol, polycarbonate polyol, polyether polyol, and polyester ether polyol can also be used.

[0023] In this technology, as the polyol having a molecular weight of 300 or less, it is preferable to use a polyol having a functionality of 2 such as the diol described above or a polyol having a functionality of 3 such as the triol described above, and it is preferable to use a polyol having a functionality of 2 and a polyol having a functionality of 3 in combination. Since a polyol having a functionality of 2 and a molecular weight of 300 or less has a small molecular weight and is easily reactive with isocyanate, it contributes to promoting the initial reaction and also contributes to promoting the subsequent reaction by the reaction heat. On the other hand, a polyol having a functionality of 3 and a molecular weight of 300 or less contributes to the construction of the three-dimensional structure of the polyurethane foam. Therefore, by using a polyol having a functionality of 2 and a polyol having a functionality of 3 in combination, it is possible to improve the reaction efficiency during production and to improve the quality of the polyurethane foam produced (such as reducing the compression set).

[0024] Among polyols having a functionality of 2, it is preferable to use 1,3-propanediol (trimethylene glycol), and among polyols having a functionality of 3, it is preferable to use 1,2,3-propanetriol (glycerin).

[0025] The amount of the polyol having a molecular weight of 300 or less used in the present technology can be freely set as long as it does not impair the action or effect of the present technology. In the present technology, the lower limit of the polyol having a molecular weight of 300 or less in the composition is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 3.0 parts by mass or more in 100 parts by mass of polyol. By setting the lower limit of the polyol having a molecular weight of 300 or less in 100 parts by mass of polyol within this range, it is possible to produce a polyurethane foam of better quality.

[0026] The upper limit of the polyol having a molecular weight of 300 or less in the composition is, for example, 10.0 parts by mass or less, preferably 9.0 parts by mass or less, more preferably 8.0 parts by mass or less, and even more preferably 7.0 parts by mass or less, per 100 parts by mass of polyol. By setting the upper limit of the polyol having a molecular weight of 300 or less in 100 parts by mass of polyol within this range, it is possible to prevent the properties of the hard segment portion (the property of reducing flexibility and increasing hardness) from appearing predominantly.

[0027] (1-3) Other polyols In the present technology, it is also possible to use polyols other than polyether polyols having a weight average molecular weight of 1200 or more and polyols having a molecular weight of 300 or less, i.e., polyols having a weight average molecular weight of more than 300 and less than 1200, as long as the action and effect of the present technology are not impaired. As the polyol having a weight average molecular weight of more than 300 and less than 1200, one or more polyols having a weight average molecular weight of more than 300 and less than 1200 can be selected and used from among general polyols that can be used in the production of polyurethane foam, such as polyester polyols, polycarbonate polyols, polyether polyols, and polyester ether polyols.

[0028] In the present technology, it is preferable to use a biomass-derived polyol as the polyol described above. As will be demonstrated in the examples described later, in the present technology, even if a biomass-derived polyol is used as a polyether polyol having a weight average molecular weight of 1200 or more or a polyol having a molecular weight of 300 or less, a good quality polyurethane foam can be produced, so that the biomass ratio of the produced polyurethane foam can be improved, and it is possible to contribute to environmental conservation and the formation of a sustainable society.

[0029] Examples of biomass-derived polyether polyols having a weight-average molecular weight of 1200 or more include condensates of polyols derived from animals and plants, and in this technology, a condensate of 1,3-propanediol derived from plants such as corn can be suitably used. The condensate of 1,3-propanediol has a straight main chain structure without branching, so that it has little steric hindrance during the reaction in the production of polyurethane foam and is smoothly polymerized. It is therefore presumed that a good quality polyurethane foam can be produced even when the amount of foam stabilizer is reduced or no foam stabilizer is used.

[0030] Examples of biomass-derived polyols with a molecular weight of 300 or less include 1,3-propanediol derived from animals and plants such as corn, and 1,2,3-propanetriol (glycerin) derived from animals and plants. For example, when a condensate of 1,3-propanediol derived from animals and plants is used as a biomass-derived polyether polyol with a weight average molecular weight of 1200 or more, by using 1,3-propanediol derived from animals and plants as a biomass-derived polyol with a molecular weight of 300 or less, steric hindrance during the reaction can be reduced when 1,3-propanediol acts as a chain extender, and more efficient polymerization can be achieved. In addition, by using 1,2,3-propanetriol (glycerin) derived from plants in addition to 1,3-propanediol derived from animals and plants as a biomass-derived polyol with a molecular weight of 300 or less, the quality of the polyurethane foam can be further improved because 1,2,3-propanetriol (glycerin) with a functional group of 3 contributes to the construction of the three-dimensional structure of the polyurethane foam.

[0031] Other biomass-derived polyols (polyols having a weight-average molecular weight of more than 300 and less than 1200) include, for example, polyols derived from animals and plants. Examples of plant-derived polyols include natural fats and oils such as castor oil, soybean oil, palm oil, palm kernel oil, coconut oil, cashew nut shell oil (CNSL (Cashew Nuts Shell Liquid)), cashew nut oil, olive oil, cottonseed oil, safflower oil, sesame oil, sunflower oil, and linseed oil, or derivatives thereof (for example, modified natural fat and oil polyols, unmodified natural fat and oil polyols, etc.).

[0032] (2) Isocyanate The isocyanate that can be used in the present technology can be freely selected from one or more isocyanates that can be used in the production of polyurethane foam, as long as the purpose and effect of the present technology are not impaired. For example, aliphatic isocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexamethane diisocyanate; aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate, xylylene diisocyanate, and polymeric polyisocyanate; modified polyisocyanates obtained by modifying these, and the like can be mentioned. Among these, in the present technology, it is preferable to use diphenylmethane diisocyanate (MDI), and it is more preferable to use polymeric MDI (crude MDI), urethane-modified MDI, and carbodiimide-modified MDI.

[0033] In addition, in the present technology, it is preferable to use an isocyanate having an average functionality of 2.3 or less. By using an isocyanate having an average functionality of 2.3 or less, the elongation of the polyurethane foam produced can be further improved. Examples of isocyanates having an average functionality of 2.3 or less include urethane-modified MDI and carbodiimide-modified MDI.

[0034] In addition, the isocyanate index of the polyurethane foam is not particularly limited as long as it does not impair the action and effect of the present technology. In the present technology, the lower limit of the isocyanate index is, for example, 90 or more, preferably 95 or more, and more preferably 100 or more. By setting the lower limit of the isocyanate index within this range, the mechanical strength (tensile strength / elongation) and hardness of the polyurethane foam can be improved.

[0035] The upper limit of the isocyanate index is, for example, not more than 120, preferably not more than 110, and more preferably not more than 105. By setting the upper limit of the isocyanate index within this range, it is possible to prevent the mechanical strength (tensile strength / elongation) and hardness of the polyurethane foam from becoming too high, and to improve the flexibility.

[0036] In the present technology, the isocyanate index is a value calculated by [(isocyanate equivalent in the composition for producing polyurethane foam / active hydrogen equivalent in the composition for producing polyurethane foam)×100].

[0037] (3) Filler The filler that can be used in the present technology can be freely selected from one or more fillers that can be used in the production of polyurethane foam, as long as the purpose and effect of the present technology are not impaired. When polyurethane foam is produced by the mechanical froth method, the filler also functions as a nucleating agent (foaming base point). Examples of the filler include metal hydroxides such as calcium carbonate, aluminum hydroxide, and magnesium hydroxide, alumina trihydrate, silica, talc, calcium carbonate, clay, etc. Among these, metal hydroxides are preferred from the viewpoint of being able to impart flame retardancy to polyurethane foam, and among metal hydroxides, aluminum hydroxide is more preferred.

[0038] The amount of filler in the composition used to produce the polyurethane foam according to the present technology can be freely set as long as it does not impair the action or effect of the present technology. In the present technology, the lower limit of the content of the filler in the composition is, for example, 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, relative to 100 parts by mass of polyol. The upper limit of the content of the filler in the composition is, for example, 20 parts by mass or less, preferably 18 parts by mass or less, more preferably 15 parts by mass or less, relative to 100 parts by mass of polyol.

[0039] (4) Catalyst A catalyst can be used in the production of polyurethane foam according to the present technology. As the catalyst that can be used in the present technology, one or more catalysts that can be used in the production of polyurethane foam can be freely selected and used as long as the action and effect of the present technology are not impaired.

[0040] Examples of the catalyst include metal catalysts (organometallic catalysts) such as organic iron compounds (iron acetylacetonate, etc.), organic nickel compounds (nickel acetylacetonate, nickel octylate, nickel naphthenate, etc.), organic tin compounds (tin(II) octylate (tin 2-ethylhexanoate, stannous octoate, etc.), organic bismuth compounds (bismuth octylate, bismuth naphthenate, etc.), organic lead compounds (lead octanoate, lead naphthenate, etc.), organic cobalt compounds (cobalt acetylacetonate, cobalt octylate, cobalt naphthenate, etc.), organic zirconium compounds (zirconium acetylacetonate, etc.), and organic zinc compounds; triethylamine, triethylenediamine (TEDA), tetramethylguanidine, and diethanolamine. , bis(2-dimethylaminoethyl)ether, N,N,N',N",N"-pentamethyldiethylenetriamine, imidazole-based compounds, piperazine-based amines such as dimethylpiperazine, N-methyl-N'-(2-dimethylamino)ethylpiperazine, and N-methyl-N'-(2-hydroxyethyl)piperazine, morpholine-based amines such as N-methylmorpholine and N-ethylmorpholine, and amine catalysts such as amines called DBU homologues, such as 1,8-diazabicyclo-[5,4,0]-undecene-7 (DBU), 1,5-diazabicyclo-[4,3,0]-nonene-5 (DBN), 1,8-diazabicyclo-[5,3,0]-decene-7 (DBD), and 1,4-diazabicyclo-[3,3,0]octene-4 (DBO).

[0041] The amount of catalyst in the composition used for producing the polyurethane foam according to the present technology can be freely set as long as it does not impair the action and effect of the present technology. In the present technology, the lower limit of the catalyst content in the composition is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, relative to 100 parts by mass of polyol. By setting the lower limit of the catalyst content in the composition within this range, various reactions during production can be controlled, and as a result, a polyurethane foam with excellent mechanical properties and appearance can be obtained.

[0042] In the present technology, the upper limit of the catalyst content in the composition is, for example, 10 parts by mass or less, preferably 8 parts by mass or less, more preferably 6 parts by mass or less, relative to 100 parts by mass of polyol. By setting the upper limit of the catalyst content in the composition within this range, it is possible to prevent instability of various reactions during production. As a result, it is possible to obtain a polyurethane foam with excellent mechanical properties and appearance.

[0043] (5) Antioxidants An antioxidant can be used in the production of polyurethane foam according to the present technology. As the antioxidant that can be used in the present technology, one or more antioxidants that can be used in the production of polyurethane foam can be freely selected and used as long as the action and effect of the present technology are not impaired. For example, one or more of naphthylamine-based, diphenylamine-based, p-phenyldiamine-based, quinoline-based, hydroquinone derivatives, monophenol-based, thiobisphenol-based, hindered phenol-based, phosphite-based, etc. can be freely combined and used.

[0044] The amount of antioxidant in the composition used to produce the polyurethane foam according to the present technology can be freely set as long as it does not impair the action or effect of the present technology. In the present technology, the lower limit of the content of the antioxidant in the composition is, for example, 0.01 parts by mass or more, preferably 0.03 parts by mass or more, and more preferably 0.05 parts by mass or more, relative to 100 parts by mass of polyol. By setting the lower limit of the content of the antioxidant in the composition within this range, the effect of preventing discoloration due to scorch prevention can be improved.

[0045] In the present technology, the upper limit of the content of the antioxidant in the composition is, for example, 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 1 part by mass or less, relative to 100 parts by mass of the polyol. Setting the upper limit of the content of the antioxidant in the composition within this range can contribute to cost reduction.

[0046] (6) Moisture absorbent A moisture absorbent can be used in the production of polyurethane foam according to the present technology. By using a moisture absorbent, unintended foaming due to moisture contained in the reaction atmosphere or materials can be prevented. In particular, when polyurethane foam is produced by the mechanical froth method, it is preferable to use a moisture absorbent. As the moisture absorbent that can be used in the present technology, one or more moisture absorbents that can be used in polyurethane foam can be freely selected and used as long as they do not impair the action and effect of the present technology. Examples of moisture absorbents include zeolite, silica gel, calcium oxide, activated carbon, potassium hydroxide, sodium hydroxide, lithium hydroxide, etc.

[0047] The amount of the moisture absorbent in the composition used in the polyurethane foam production according to the present technology can be freely set as long as it does not impair the action or effect of the present technology. In the present technology, the lower limit of the content of the moisture absorbent in the composition is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, relative to 100 parts by mass of polyol. The upper limit of the content of the moisture absorbent in the composition is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 3 parts by mass or less, relative to 100 parts by mass of polyol.

[0048] (7) Foam stabilizer In the present technology, as demonstrated in the examples described below, a good quality polyurethane foam can be produced without using a foam stabilizer, but it is also possible to use a foam stabilizer. Even when a foam stabilizer is used, the present technology allows a good quality polyurethane foam to be produced with a smaller amount of foam stabilizer than in the past.

[0049] As the foam stabilizer that can be used in the present technology, one or more foam stabilizers that can be used in the production of polyurethane foam can be freely selected and used as long as the action and effect of the present technology are not impaired. For example, silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, surfactants, etc. can be mentioned. Silicone-based foam stabilizers include those mainly composed of siloxane chains, those in which the siloxane chain and polyether chain have a linear structure, those that are branched and branched, those in which the polyether chain is modified to be pendant to the siloxane chain, etc.

[0050] The amount of the foam stabilizer in the composition used to produce the polyurethane foam according to the present technology can be freely set as long as it does not impair the action or effect of the present technology. In the present technology, for example, the amount is 10 parts by mass or less, preferably 7 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and particularly preferably 0 parts by mass, relative to 100 parts by mass of polyol. Reducing the content of the foam stabilizer in the composition can contribute to environmental conservation.

[0051] (8) Foam-making gas A foam-forming gas can be used in the production of polyurethane foam according to the present technology. As the foam-forming gas that can be used in the present technology, one or more types of foam-forming gas that can be used in the production of polyurethane foam can be freely selected and used as long as the action and effect of the present technology are not impaired.

[0052] Examples of the foam-forming gas include inert gases such as dry air and nitrogen. The mixing ratio of the foam-forming gas to other raw materials can be freely set according to the application of the polyurethane foam to be produced, as long as it does not impair the purpose and effect of the present technology. In the present technology, the mixing ratio of the foam-forming gas to other raw materials can be set to, for example, 10% by volume or more, preferably 15% by volume or more, and more preferably 20% by volume or more, based on 100% by volume of the foam-forming gas and other raw materials combined.

[0053] In this technology, the upper limit of the mixing ratio of the foam-forming gas with other raw materials can be set to, for example, 100 volume % or less, 95 volume % or less, or 90 volume % or less out of 100 volume % of the foam-forming gas and other raw materials combined.

[0054] (9) Foaming agent The polyurethane foam according to the present technology can be produced by a mechanical froth method as described below, and in that case, the polyurethane foam according to the present technology can be produced without a blowing agent, but the present technology also allows the use of a blowing agent. As the blowing agent that can be used in the present technology, one or more blowing agents that can be used in the production of polyurethane foam can be freely selected and used as long as they do not impair the purpose and effect of the present technology.

[0055] The foaming agent that can be used in the present technology may be either a chemical foaming agent or a physical foaming agent. Examples of chemical foaming agents include reactive foaming agents that react with the above-mentioned isocyanates, such as water, carboxylic acids such as formic acid and acetic acid, to generate carbon dioxide gas and foam, physical foaming agents such as volatile hydrocarbons, and organic or inorganic thermal decomposition type chemical foaming agents. Examples of inorganic foaming agents include sodium hydrogen carbonate, ammonium carbonate, sodium carbonate, ammonium hydrogen carbonate, ammonium nitrite, sodium borohydride, and anhydrous monosodium citrate.

[0056] Examples of physical blowing agents include fluorocarbons such as hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), hydrocarbons such as heptane, hexane, pentane, and cyclopentane, and carbon dioxide.

[0057] The amount of the blowing agent in the composition used to produce the polyurethane foam according to the present technology can be freely set as long as it does not impair the action and effect of the present technology. In the present technology, the content of the blowing agent in the composition is, for example, 10 parts by mass or less, preferably 7 parts by mass or less, and more preferably 5 parts by mass or less, relative to 100 parts by mass of polyol. By setting the upper limit of the content of the blowing agent in the composition within this range, it is possible to suppress formation defects due to excessive foaming, and also to contribute to cost reduction.

[0058] (10)Other In the production of the polyurethane foam according to the present technology, one or more of various components that can be used in the production of polyurethane foam can be freely selected and used as other components depending on the purpose, as long as the action and effect of the present technology are not impaired.

[0059] Examples of components that can be used in the production of polyurethane foams according to the present technology include flame retardants, pigments, stabilizers, plasticizers, colorants, crosslinking agents, antibacterial agents, dispersants, and ultraviolet absorbers.

[0060] 2.Polyurethane foam The polyurethane foam according to the present technology is obtained from a composition containing a polyol containing a polyether polyol having a weight average molecular weight of 1200 or more and a polyol having a molecular weight of 300 or less, and an isocyanate. It may also contain a foaming gas. That is, the polyurethane foam according to the present technology is produced using the above-mentioned composition. Representative physical properties of the polyurethane foam according to the present technology will be described below.

[0061] (1) Density The polyurethane foam according to the present technology uses as its raw material a polyol containing a polyether polyol having a weight average molecular weight of 1200 or more and a polyol having a molecular weight of 300 or less, and the density can be adjusted according to the purpose without using a foam stabilizer. The density of the polyurethane foam according to the present technology can be freely set according to the purpose and application. The lower limit of the density is, for example, 80 kg / m3 More than 100kg / m 3 More than 150kg / m 3 More preferably, 200 kg / m 3 By setting the lower limit of the density within this range, the composition can be suitably used as a cushioning material for absorbing vibrations and shocks in electronic devices such as mobile phones, cameras, and televisions, and electric devices such as home appliances, as a sealing material for various batteries, and as a sealing material for the periphery of batteries and electronic control units of electric vehicles.

[0062] The upper limit of the density of the polyurethane foam according to the present invention can be freely set as long as it does not impair the function and effect of the present invention. For example, it is set to 800 kg / m 3 Below 700kg / m 3 Below 600kg / m 3 By setting the density of the polyurethane foam within this range, it is possible to impart cushioning properties without impairing the flexibility of the polyurethane foam (preventing it from becoming hard).

[0063] In this technology, the density is a value measured by a method conforming to JIS K6401:2011.

[0064] (2) Silicone content In order to contribute to environmental conservation, it is preferable that the silicone content of polyurethane foam is low. By using this technology, the amount of foam stabilizer such as silicone-based foam stabilizer can be reduced, or as shown in the examples described below, good quality polyurethane foam can be produced without using foam stabilizer such as silicone-based foam stabilizer, so that the silicone content of the produced polyurethane foam can be reduced. Specifically, it is preferable to use this technology so that the silicone content measured in accordance with the method based on VDA (Verband der Automobilindustrie) 278 is, for example, 1 ppm or less, preferably 0.5 ppm or less, and more preferably 0.25 ppm or less.

[0065] (3) Biomass rate As will be demonstrated in the examples described below, this technology can produce high-quality polyurethane foams even when using biomass-derived polyols, thereby improving the biomass ratio of the produced polyurethane foam and contributing to environmental conservation and the creation of a sustainable society. The biomass ratio of the polyurethane foam according to this technology can be, for example, 40% or more, preferably 50% or more, and more preferably 60% or more.

[0066] In this technology, the biomass ratio is a value calculated using the following formula. Biomass rate (%) = (weight of biomass material / weight of total raw materials) x 100

[0067] (4) Tensile strength The tensile strength of the polyurethane foam according to the present technology can be freely set as long as it does not impair the function and effect of the present technology. The lower limit of the tensile strength of the polyurethane foam according to the present technology is, for example, 0.4 MPa or more, preferably 0.7 MPa or more, and more preferably 1.0 MPa or more. The upper limit of the tensile strength of the polyurethane foam according to the present technology is, for example, 5.0 MPa or less, 4.0 MPa or less, or 3.0 MPa or less.

[0068] In this technology, the tensile strength is a value measured by a method conforming to JIS K6251:2010.

[0069] (5) Elongation The elongation of the polyurethane foam according to the present technology can be freely set as long as it does not impair the action and effect of the present technology. The lower limit of the elongation of the polyurethane foam according to the present technology is, for example, 150% or more, preferably 180% or more, more preferably 200% or more, even more preferably 250% or more, and particularly preferably 300% or more. The upper limit of the elongation of the polyurethane foam according to the present technology is, for example, 1000% or less, 900% or less, or 800% or less.

[0070] In this technology, the elongation is a value measured by a method conforming to JIS K6251:2010.

[0071] (6) Compressive set The compression set of the polyurethane foam according to the present technology can be freely set as long as it does not impair the function and effect of the present technology. The lower limit of the compression set of the polyurethane foam according to the present technology is, for example, 0.1% or more, 0.3% or more, or 0.5% or more. The upper limit of the compression set of the polyurethane foam according to the present technology is, for example, 10% or less, preferably 8% or less, and more preferably 5% or less.

[0072] In this technology, the compression set is a value measured by a method conforming to JIS K6401:2011.

[0073] (7)Applications The polyurethane foam according to the present technology can be used for various purposes in various fields by utilizing its high quality. For example, it can be suitably used for furniture such as sofas and chairs, bedding such as mattresses and pillows, clothing such as underwear, daily necessities such as dish sponges and cleaning sponges, products for vehicle and aircraft interiors such as car seats, architectural joint materials, architectural cushioning materials, architectural sealing materials, sealing materials for home appliances, cushioning materials for electrical devices, cushioning materials for electronic devices, sealing materials for electrical devices, sealing materials for electronic devices, sealing materials for various batteries, soundproofing materials, packaging materials, insulation materials for vehicles, sealing materials for vehicle batteries, sealing materials for vehicle electronic control units, dew prevention materials, interior materials, insulation materials for home appliances, insulation materials for pipes, various covers, cushioning materials, toys, miscellaneous goods, etc.

[0074] The polyurethane foam according to the present technology can be particularly suitably used as a substrate for adhesive tapes in various fields. In particular, the polyurethane foam produced by utilizing the present technology with reduced or no foam stabilizer has a very low silicon content, and can therefore be particularly suitably used for adhesive tapes in electronic devices, precision instruments, and the like.

[0075] 3. Manufacturing method of polyurethane foam The polyurethane foam according to the present technology can be produced by mixing the above-mentioned components of the composition to prepare a composition, and foaming the prepared composition by a known method. As the methods of the resinification reaction and the foaming reaction, any general method can be freely combined and used as long as it does not impair the action and effect of the present technology.

[0076] In the method for producing polyurethane foam according to the present disclosure, it is particularly preferable to employ a mechanical froth method, which makes it easier to adjust the density and allows the production of high density polyurethane foam compared to chemical foaming methods.

[0077] As a specific method of the mechanical flossing method, a general mechanical flossing method can be adopted as long as it does not impair the action and effect of the present technology. For example, the raw materials other than the isocyanate and the foaming gas of the above-mentioned composition are charged and mixed into a mixing head at a timing according to the type and purpose of each raw material to prepare an intermediate composition. The isocyanate is charged and mixed into the prepared intermediate composition, and the foaming gas is mixed therein while stirring and mixing to make it homogeneous, and then the mixture is heated and cured on a release paper or in a mold to produce a polyurethane foam.

[0078] In addition, the present technology can have the following configuration. [1] A polyurethane foam obtained from a composition containing a polyol and an isocyanate, The polyol contains a polyether polyol having a weight average molecular weight of 1,200 or more and a polyol having a molecular weight of 300 or less. Polyurethane foam. [2] The polyurethane foam according to [1], having a silicone content of 0.25 ppm or less as measured in accordance with a method based on VDA278. [3] The polyurethane foam according to [1] or [2], wherein the polyether polyol having a weight average molecular weight of 1,200 or more is a biomass-derived polyether polyol. [4] Density is 100kg / m 3 The polyurethane foam according to any one of [1] to [3] above. [5] The polyurethane foam according to any one of [1] to [4], wherein the polyol having a molecular weight of 300 or less contains a polyol having a functionality of two and a polyol having a functionality of three. [6] An adhesive tape substrate using the polyurethane foam according to any one of [1] to [5]. EXAMPLES

[0079] The present technology will be described in more detail below based on examples. Note that the examples described below are representative examples of the present technology, and the scope of the present technology is not to be interpreted narrowly by these examples.

[0080] (1) Manufacture of polyurethane foam A polyurethane foam-producing composition was prepared using the raw materials shown in Table 1 below. The prepared polyurethane foam-producing composition was then charged into a mixing head and mixed by stirring to homogenize while mixing in a foam-forming gas (inert gas: nitrogen). The mixed raw materials were then fed onto a continuously fed film of a given thickness and heat-cured at 120 to 200°C to produce a polyurethane foam.

[0081] (2) Evaluation The density, tensile strength, elongation, compression set and silicone content of the produced polyurethane foams were measured by the methods described below.

[0082] [density] The density was measured according to the method in accordance with JIS K6401:2011.

[0083] [Tensile strength] [Elongation] The tensile strength was measured according to a method in accordance with JIS K6251:2010.

[0084] [Compression set] The compression set was measured using a method in accordance with JIS K6401:2011.

[0085] [Silicone content] The silicone content was measured using a method in accordance with VDA278.

[0086] (3) Results The results are shown in Table 1 below. [Table 1]

[0087] (4) Discussion As shown in Table 1, in Comparative Example 1, which did not use a polyol having a molecular weight of 300 or less, foaming and dispersion by stirring were insufficient, and the foam coalesced and broke during thermoforming, resulting in unevenly scattered foam, making it difficult to prepare test pieces, and therefore it was impossible to measure tensile strength, elongation, and compression set. In Comparative Example 2, which used biomass-derived polyether polyol 3 having a weight average molecular weight of 1200 or more, the biomass ratio was high, and since no silicone-based foam stabilizer was used, the amount of silicone components was below the detection limit. However, since no polyol having a molecular weight of 300 or less was used, the reactivity was low, and the product cured poorly and became gel-like, making it impossible to mold.

[0088] On the other hand, in Examples 1 to 6, which used a condensate of corn-derived 1,3-propanediol as a polyether polyol having a weight average molecular weight of 1200 or more, and corn-derived 1,3-propanediol and glycerin as a polyol having a molecular weight of 300 or less, polyurethane foams having physical properties equal to or better than those of Reference Example 1 could be produced without using a foam stabilizer. Furthermore, since Examples 1 to 6 used biomass-derived polyether polyol 3, the biomass ratio was high, and since no silicone-based foam stabilizer was used, the amount of silicone components was below the detection limit.

[0089] Comparing the Examples, Examples 3 to 6, which used a polyol with a functionality of 2 and a polyol with a functionality of 3 in combination, showed reduced compression set results compared to Examples 1 and 2, which used a polyol with a functionality of 2 or 3 alone as a polyol with a molecular weight of 300 or less. Also, Examples 1, 2, and 4 to 6, which used an isocyanate with a functionality of 2.3 or less, showed improved elongation results compared to Example 3, which used an isocyanate with a functionality of more than 2.3.

Claims

1. A polyurethane foam obtained from a composition containing a polyol and an isocyanate, The polyol contains a polyether polyol having a weight average molecular weight of 1,200 or more and a polyol having a molecular weight of 300 or less. Polyurethane foam.

2. 2. The polyurethane foam according to claim 1, having a silicone content of 0.25 ppm or less, as measured in accordance with a method based on VDA 278.

3. 3. The polyurethane foam according to claim 1, wherein the polyether polyol having a weight average molecular weight of 1,200 or more is a biomass-derived polyether polyol.

4. Density is 100 kg / m ３ The polyurethane foam according to claim 1 or 2.

5. 3. The polyurethane foam according to claim 1, wherein the polyol having a molecular weight of 300 or less contains a polyol having a functionality of 2 and a polyol having a functionality of 3.

6. 3. An adhesive tape substrate comprising the polyurethane foam according to claim 1 or 2.

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