JP5350315B2 - Polyurethane elastomers and molded products - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane elastomer which can secure excellent transparency, is excellent in heat resistance, can suppress tackiness, is excellent in yellowing resistance, and additionally, is excellent in the refractive index; and to provide a molding obtained by using the same. <P>SOLUTION: The polyurethane elastomer is obtained by reacting a polyisocyanate containing 1, 4-bis(isocyanatomethyl)cyclohexane, a high-molecular weight polyol, and a chain extender containing a branched low-molecular weight diol in a proportion of 5 to 45 mol% to the total molar number of the chain extender, wherein the equivalent weight ratio of the isocyanate group of the polyisocyanate to the hydroxide group of the high-molecular weight polyol is in the range of 2 to 6. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a polyurethane elastomer and a molded article in which the polyurethane elastomer is used.

  In various electronic devices, in order to improve operability, the movable contact body provided in the operation unit is illuminated with a light emitting element or the like, and covered and protected by a light guide sheet that can transmit the irradiated light. well known.

  Conventionally, such a light guide sheet is formed of polycarbonate or the like having excellent light transmission properties. However, polycarbonate is not sufficiently flexible, and the operability of the movable contact body (key operability such as click feeling) is improved. It may be damaged. Therefore, for example, it has been proposed to form the light guide sheet from a polyurethane elastomer having excellent flexibility.

  More specifically, for example, the pressure input type movable contact, the adhesive layer holding the movable contact, and the light incident from the light source provided at the side position is guided to illuminate the upper surface side of the movable contact. A movable contact body with a light guide function, comprising a base sheet made of an insulating film made of thermoplastic plastic polyurethane having excellent flexibility, and a film having a refractive index lower than that of the base sheet and interposed between the base sheet and the adhesive layer Has been proposed (see, for example, Patent Document 1).

JP 2009-164114 A

  However, in the movable contact body with a light guide function described in Patent Document 1, an insulating film made of a thermoplastic plastic polyurethane is used without any particular limitation, but a normal thermoplastic plastic polyurethane has insufficient heat resistance. In addition, since the tackiness is strong, there is a problem that workability and operability during processing are inferior.

  Moreover, as a light guide sheet | seat, in order to aim at the improvement of the designability, while ensuring transparency, it is further requested | required to ensure the outstanding yellowing resistance.

  An object of the present invention is to secure excellent transparency, excellent heat resistance, suppress tackiness, and also have excellent anti-yellowing property and high refractive index, and its polyurethane The object is to provide a molded article obtained by using an elastomer.

  In order to achieve the above object, the polyurethane elastomer of the present invention is a polyurethane elastomer obtained by reacting at least a polyisocyanate, a high molecular weight polyol, and a chain extender, wherein the polyisocyanate is 1,4. -Bis (isocyanatomethyl) cyclohexane, the chain extender contains a branched low molecular weight diol in a proportion of 5 to 45 mol% based on the total number of moles of the chain extender, and the high molecular weight The equivalent ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyol is 2 to 6.

  In the polyurethane elastomer of the present invention, the parallel light transmittance is preferably 90% or more.

  The polyurethane elastomer of the present invention preferably has a softening temperature of 130 ° C. or higher.

  In the polyurethane elastomer of the present invention, it is preferable that the branched low molecular weight diol has 1 to 5 total carbon atoms in the branched chain.

  In the polyurethane elastomer of the present invention, the branched low molecular weight diol is 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-methyl-1,5-pentanediol, It is preferably at least one selected from the group consisting of 3-methyl-1,5-pentanediol and 2,4-diethyl-1,5-pentanediol.

  The polyurethane elastomer of the present invention preferably contains an anthraquinone-based bluing agent in a proportion of 0.1 to 5 ppm.

  The molded article of the present invention is characterized by using the polyurethane elastomer described above.

  Moreover, it is suitable that the molded article of the present invention is molded as a light guide film.

  The molded product of the present invention is preferably molded as a light guide sheet.

  According to the polyurethane elastomer of the present invention, excellent heat resistance can be ensured and tackiness can be suppressed, so that excellent workability and operability can be ensured.

  In addition, the polyurethane elastomer of the present invention has a high refractive index and is excellent in transparency and yellowing resistance, so that it is excellent in design.

  Therefore, according to the polyurethane elastomer of the present invention, a molded product requiring optical characteristics and design properties can be formed with good workability and used.

  And since the polyurethane elastomer of the present invention is used, the molded product of the present invention can be formed and used with good workability, and can ensure excellent refractive index, transparency and design. it can.

  Therefore, the molded article of the present invention can be suitably used especially as an optical sheet such as a light guide film or a light guide sheet.

  The polyurethane elastomer of the present invention can be obtained, for example, as a thermoplastic polyurethane elastomer, a thermosetting polyurethane elastomer (cast polyurethane elastomer) or the like by reacting at least a polyisocyanate, a high molecular weight polyol, and a chain extender. It is done.

  In the present invention, the polyisocyanate is an organic compound having two or more isocyanate groups and contains 1,4-bis (isocyanatomethyl) cyclohexane. For example, for the total number of moles of isocyanate groups, The isocyanate group of 1,4-bis (isocyanatomethyl) cyclohexane is contained in a proportion of 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. doing. Most preferably, it contains 100 mol%.

  1,4-bis (isocyanatomethyl) cyclohexane includes cis-1,4-bis (isocyanatomethyl) cyclohexane (hereinafter referred to as cis 1,4 isomer) and trans-1,4-bis ( There are stereoisomers of isocyanatomethyl) cyclohexane (hereinafter referred to as trans 1,4), and in the present invention, 1,4-bis (isocyanatomethyl) cyclohexane is preferably trans 1,4, 80 mol% or more, more preferably 85 mol% or more.

  1,4-bis (isocyanatomethyl) cyclohexane is, for example, a two-stage method (direct method) or a salt formation method described in JP-A-7-309827, or Japanese Patent Application Laid-Open No. 2004-244349. It can be produced by the non-phosgene method described in Japanese Unexamined Patent Publication No. 2003-212835.

  In addition, 1,4-bis (isocyanatomethyl) cyclohexane can also be prepared as a modified product as long as the excellent effects of the present invention are not inhibited.

  Examples of the modified form of 1,4-bis (isocyanatomethyl) cyclohexane include, for example, a multimer of 1,4-bis (isocyanatomethyl) cyclohexane (such as a dimer (for example, uretidione modified form)) and a trimer (for example, isocyanurate). Modified body, iminooxadiazinedione modified body, etc.), biuret modified body (for example, biuret modified body produced by reaction of 1,4-bis (isocyanatomethyl) cyclohexane and water), allophanate modified body ( For example, 1,4-bis (isocyanatomethyl) cyclohexane and monool or a low molecular weight polyol (described later), an allophanate modified product, etc., a polyol modified product (for example, 1,4-bis (isocyanatomethyl) ) Cyclohexane and low molecular weight polyol (described below) or Modified polyols produced by reaction with molecular weight polyol (described later), modified oxadiazine trione (eg, oxadiazine trione produced by reaction of 1,4-bis (isocyanatomethyl) cyclohexane and carbon dioxide gas) Etc.), carbodiimide-modified products (carbodiimide-modified products produced by decarboxylation condensation reaction of 1,4-bis (isocyanatomethyl) cyclohexane), and the like.

  In addition, the polyisocyanate is a polyisocyanate other than the other polyisocyanates, for example, aliphatic polyisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane, and aromatic, as long as the excellent effects of the present invention are not impaired. Group polyisocyanate, araliphatic polyisocyanate, and the like.

  Examples of the aliphatic polyisocyanate include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), octamethylene diisocyanate, nonamethylene diisocyanate, and 2,2′-dimethylpentane diisocyanate. 2,2,4-trimethylhexane diisocyanate, decamethylene diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,6,11-undecamethylene Triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanatomethyl Kutan, 2,5,7-trimethyl-1,8-diisocyanate-5-isocyanatomethyloctane, bis (isocyanatoethyl) carbonate, bis (isocyanatoethyl) ether, 1,4-butylene glycol dipropyl ether-ω , Ω′-diisocyanate, lysine isocyanatomethyl ester, lysine triisocyanate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, 2-isocyanatopropyl-2,6-diisocyanatohexanoate, bis (4- Isocyanate-n-butylidene) pentaerythritol, 2,6-diisocyanatomethylcaproate and the like.

  Examples of alicyclic polyisocyanates (excluding 1,4-bis (isocyanatomethyl) cyclohexane) include, for example, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, trans, trans-, trans, cis- And cis, cis-dicyclohexylmethane diisocyanate and mixtures thereof (hydrogenated MDI), 1,3- or 1,4-cyclohexane diisocyanate and mixtures thereof, 1,3- or 1,4-bis (isocyanatoethyl) Cyclohexane, methylcyclohexane diisocyanate, 2,2'-dimethyldicyclohexylmethane diisocyanate, dimer acid diisocyanate, 2,5-diisocyanatomethylbicyclo [2,2,1] -heptane, its isomer 2,6-diiso Anatomethylbicyclo [2,2,1] -heptane (NBDI), 2-isocyanatomethyl 2- (3-isocyanatopropyl) -5-isocyanatomethylbicyclo- [2,2,1] -heptane, 2- Isocyanatomethyl-2- (3-isocyanatopropyl) -6-isocyanatomethylbicyclo- [2,2,1] -heptane, 2-isocyanatomethyl 3- (3-isocyanatopropyl) -5- (2 -Isocyanatoethyl) -bicyclo- [2,2,1] -heptane, 2-isocyanatomethyl 3- (3-isocyanatopropyl) -6- (2-isocyanatoethyl) -bicyclo- [2,2, 1] -heptane, 2-isocyanatomethyl 2- (3-isocyanatopropyl) -5- (2-isocyanatoethyl) -bicyclo- [2,2,1] -heptane, 2- Socia diisocyanate methyl 2- (3-isocyanatopropyl) -6- (2-isocyanatoethyl) - bicyclo - [2,2,1] - heptane, and the like.

  Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, and isomer mixtures of these tolylene diisocyanates (TDI), 4,4′-diphenylmethane diisocyanate, 2,4. Examples include '-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate, and any isomer mixture of these diphenylmethane diisocyanates (MDI), toluidine diisocyanate (TODI), paraphenylene diisocyanate, naphthalene diisocyanate (NDI), and the like.

  Examples of the araliphatic polyisocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof (XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate or a mixture thereof (TMXDI), etc. Is mentioned.

  In addition, other polyisocyanates can be prepared as a modified product as long as the excellent effects of the present invention are not impaired.

  Examples of other polyisocyanate modified products include other polyisocyanate multimers (dimers, trimers, etc.), biuret modified products, allophanate modified products, polyol modified products, oxadiazine trione modified products, carbodiimide modified products, and the like. Can be mentioned.

  Other polyisocyanates are preferably pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), trans, trans-, trans, cis-, and cis, cis-dicyclohexylmethane diisocyanate and mixtures thereof (hydrogenated MDI). 2,5-diisocyanatomethylbicyclo [2,2,1] -heptane, its isomer 2,6-diisocyanatomethylbicyclo [2,2,1] -heptane (NBDI), 2,4 -Tolylene diisocyanate and 2,6-tolylene diisocyanate and isomer mixtures of these tolylene diisocyanates (TDI), 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate and 2,2'-diphenylme Diisocyanates and any isomeric mixture of these diphenylmethane diisocyanates (MDI), toluidine diisocyanate (TODI), 1,3- or 1,4-xylylene diisocyanate or mixtures thereof (XDI), and other polyisocyanates The modified body is mentioned.

  In addition, 1,3-bis (isocyanatomethyl) cyclohexane includes cis-1,3-bis (isocyanatomethyl) cyclohexane (hereinafter referred to as cis 1,3 form), and trans-1,3- There is a stereoisomer of bis (isocyanatomethyl) cyclohexane (hereinafter referred to as trans 1,3), and 1,3-bis (isocyanatomethyl) cyclohexane and 1,4-bis (isocyanatomethyl) cyclohexane When used in combination, 1,3-bis (isocyanatomethyl) cyclohexane is trans 1,3, preferably 50 mol% or more, more preferably 70 mol% or more, particularly preferably 90 mol%. Contains above.

  Moreover, said polyisocyanate and monoisocyanate can be used together in the range which does not inhibit the outstanding effect of this invention.

  Monoisocyanate is an organic compound having one isocyanate group, and examples thereof include methyl isocyanate, ethyl isocyanate, n-hexyl isocyanate, cyclohexyl isocyanate, 2-ethylhexyl isocyanate, phenyl isocyanate, and benzyl isocyanate.

  In the present invention, the high molecular weight polyol is an organic compound having two or more hydroxyl groups and having a number average molecular weight of, for example, 400 to 8000, preferably 800 to 4000, and more preferably 800 to 3000.

  The number average molecular weight of the high molecular weight polyol can be calculated from the hydroxyl value of the high molecular weight polyol (determined from JIS K1557-1 (2007)) and the average number of functional groups.

  Examples of the high molecular weight polyol include polyether polyol, polyester polyol, polycarbonate polyol, and polyurethane polyol.

  Examples of the polyether polyol include polyoxyalkylene polyol and polytetramethylene ether glycol.

  The polyoxyalkylene polyol is, for example, an addition polymer of alkylene oxide using a low molecular weight polyol or a low molecular weight polyamine as an initiator.

  Examples of the alkylene oxide include propylene oxide, ethylene oxide, butylene oxide, styrene oxide, and the like. These alkylene oxides can be used alone or in combination of two or more. Of these, propylene oxide and ethylene oxide are preferable.

  Further, the polyoxyalkylene polyol has a primary hydroxylation rate at the molecular end of, for example, at least 50 mol%, and preferably 70 mol%. If the primary hydroxylation rate at the molecular end of the polyoxyalkylene polyol is the above value, the reaction completion rate with the polyisocyanate can be improved.

  Examples of the catalyst for preparing the polyoxyalkylene polyol include phosphazenium compounds described in Japanese Patent No. 3905638. If a polyoxyalkylene polyol is prepared using such a catalyst, a polyoxyalkylene polyol with a small amount of monool by-products can be obtained.

  Examples of the low molecular weight polyol include ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 2-methyl-1,3-propanediol, 1, 5-pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 2,6-dimethyl-1-octene- 3,8-diol, alkane (carbon number 7-22) diol, cyclohexanedimethanol, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, bishydroxyethoxybenzene, xylene glycol, bishydroxyethylene terephthalate, bisphenol A , Diethylene glycol, Dihydric alcohols such as reoxyethylene glycol, tetraoxyethylene glycol, pentaoxyethylene glycol, hexaoxyethylene glycol, dipropylene glycol, trioxypropylene glycol, tetraoxypropylene glycol, pentaoxypropylene glycol, hexaoxypropylene glycol, for example Glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolpropane, 2,2-bis ( Trihydric alcohols such as hydroxymethyl) -3-butanol and other aliphatic triols (8 to 24 carbon atoms), for example, tetramethylolmethane (pentaerythritol), Tetravalent alcohols such as glycerin, for example, pentavalent alcohols such as xylitol, for example, hexavalent alcohols such as sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol, dipentaerythritol, for example, 7-valent alcohols such as perseitol Examples thereof include octahydric alcohols such as sucrose. Moreover, as a low molecular weight polyol, the addition polymer which added alkylene oxides, such as a propylene oxide and ethylene oxide, for example to said 1-8 octahydric alcohol is also contained.

  Examples of the low molecular weight polyamine include aliphatic diamines such as ethylenediamine, and aromatic diamines such as tolylenediamine.

  In addition, the number average molecular weight of the polyoxyalkylene polyol is preferably 800 to 4000, and more preferably 800 to 3000.

  Examples of the polytetramethylene ether glycol include a ring-opening polymer obtained by cationic polymerization of tetrahydrofuran, and an amorphous (room temperature liquid) polytetramethylene ether glycol obtained by copolymerizing the above-described dihydric alcohol with a polymerization unit of tetrahydrofuran. Is mentioned.

  In addition, the number average molecular weight of polytetramethylene ether glycol is preferably 800 to 8000, more preferably 800 to 4000, and particularly preferably 800 to 3000.

  Examples of the polyester polyol include polycondensates obtained by reacting the above-described low molecular weight polyol and polybasic acid under known conditions.

  Examples of the polybasic acid include oxalic acid, malonic acid, succinic acid, methyl succinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, and 3-methyl-3-ethylglutaric acid. , Azelaic acid, sebacic acid, other aliphatic dicarboxylic acids (carbon number 11-13), suberic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, octadecanedioic acid, nonadecanedioic acid Carboxylic acids such as acid, eicosane diacid, methylhexane diacid, citraconic acid, hydrogenated dimer acid, maleic acid, fumaric acid, itaconic acid, orthophthalic acid, isophthalic acid, terephthalic acid, toluene dicarboxylic acid, dimer acid and het acid And acid anhydrides, acid halides, ricinoleic acid derived from these carboxylic acids, 1 - such as hydroxy stearic acid.

  Specific examples of the polycondensation product of the low molecular weight polyol and the polybasic acid include poly (ethylene butylene adipate) polyol, poly (ethylene adipate) polyol, poly (ethylene propylene adipate) polyol, and poly (propylene adipate) polyol. And adipic acid-based polyester polyols such as poly (butylene hexane adipate) polyol and poly (butylene adipate) polyol.

  Examples of the polyester polyol include castor oil polyol, or a modified castor oil polyol obtained by reacting castor oil polyol and polypropylene glycol.

  Further, as the polyester polyol, for example, polycaprolactone polyol, polyvalerolactone polyol obtained by ring-opening polymerization of lactones such as ε-caprolactone and γ-valerolactone, using the above-described low molecular weight polyol as an initiator, Furthermore, the lactone type | system | group polyol which copolymerized said dihydric alcohol to them etc. are mentioned.

  In addition, the number average molecular weight of the polyester polyol is preferably 800 to 4000, and more preferably 800 to 3000.

  Moreover, when the high molecular weight polyol is a polyester polyol, it is preferable to add a carbodiimide group-containing compound having a carbodiimide group to the polyester polyol. By adding a carbodiimide group-containing compound, the hydrolysis resistance of the polyurethane elastomer can be improved.

  Examples of the carbodiimide group-containing compound include carbodiimides described in JP-A-9-208649. More specific commercial products include, for example, Carbodilite (manufactured by Nisshinbo Industries, Inc.), Starvacol I-LF (manufactured by Rhein Chemie), stabilizer 7000 (manufactured by RASCHIG GmbH), and the like.

  Moreover, it is preferable to add 0.01-2 mass parts of carbodiimide group containing compounds with respect to 100 mass parts of polyester polyols, for example.

  Examples of the polycarbonate polyol include a ring-opening polymer of ethylene carbonate using the above dihydric alcohol as an initiator, and examples thereof include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1 Polycarbonate diols obtained by condensation reaction of dihydric alcohols such as 1,6-hexanediol and carbonates such as dimethyl carbonate, diethyl carbonate and diphenyl carbonate, and amorphous (room temperature liquid) polycarbonate polyols.

  The number average molecular weight of the polycarbonate polyol is preferably 800 to 4000, and more preferably 800 to 3000.

  Polyurethane polyol reacts with the above polyisocyanate at a ratio in which the equivalent ratio of hydroxyl group to isocyanate group (OH / NCO) exceeds 1 with the above high molecular weight polyol (eg, polyether polyol, polyester polyol, polycarbonate polyol, etc.). By making it, it can be obtained as a polyether polyurethane polyol, a polyester polyurethane polyol, a polycarbonate polyurethane polyol, or a polyester polyether polyurethane polyol.

  These high molecular weight polyols can be used alone or in combination of two or more. Of these, adipic acid polyester polyol, polytetramethylene ether glycol, polycarbonate polyol, amorphous polytetramethylene ether glycol, and amorphous polycarbonate polyol are preferable. Moreover, as for these number average molecular weights, 800-3000 are suitable.

  As will be described in detail later, in the reaction of polyisocyanate, high molecular weight polyol and chain extender, the equivalent ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of these high molecular weight polyols is 2 to 6, preferably 2 .2 to 5.5, and more preferably 2.5 to 5.

  In the present invention, examples of the chain extender include a low molecular weight diol.

  The low molecular weight diol is an organic compound having two hydroxyl groups and a number average molecular weight of, for example, 40 to 600, preferably less than 400, such as a linear low molecular weight diol or a branched low molecular weight diol. Etc.

  The linear low molecular weight diol is a low molecular weight diol containing no branched chain, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,4-dihydroxy-2-butene, diethylene glycol, trioxyethylene glycol, tetraoxyethylene glycol, pentaoxyethylene glycol, hexaoxyethylene glycol, dipropylene glycol, trioxypropylene glycol, tetraoxypropylene glycol, penta Examples thereof include linear dihydric alcohols such as oxypropylene glycol and hexaoxypropylene glycol.

  These linear low molecular weight diols can be used alone or in combination of two or more.

  Preferred examples of the linear low molecular weight diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and diethylene glycol, more preferably 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and more preferably 1,4-butanediol.

  When such a linear low molecular weight diol is used, the softening temperature, tackiness and impact resilience can be improved.

  The branched low molecular weight diol is a low molecular weight diol containing a branched chain, for example, propylene glycol (total number of carbons of the branched chain: 1), 1,3-butanediol (total number of carbons of the branched chain: 1). 1,2-butanediol (total number of branched carbons: 2), 2-methyl-1,3-propanediol (total number of branched carbons: 1), neopentyl glycol (total number of branched carbons: 2), 2-methyl-1,5-pentanediol (total carbon number of branched chain: 1), 3-methyl-1,5-pentanediol (total number of carbon atoms of branched chain: 1), 2,4-diethyl 1,5-pentanediol (total number of branched carbons: 4), 2,6-dimethyl-1-octene-3,8-diol (total number of branched carbons: 4), 2-ethyl-3- Propyl-1,3-propanediol (total number of carbons in the branched chain: 5 1-phenyl-1,2-ethanediol (total number of carbon atoms in the branched: 6), and the like branched dihydric alcohol such.

  These branched low molecular weight diols can be used alone or in combination of two or more.

  The branched low molecular weight diol is preferably a branched low molecular weight diol having 1 to 5 carbon atoms in the branched chain.

  If a branched low molecular weight diol having 1 to 5 carbon atoms in the branched chain is used, transparency (total light transmittance, parallel light transmittance, diffuse light transmittance and haze) and refractive index may be improved. it can.

  Further, as such a branched low molecular weight diol, 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-methyl-1,5-pentanediol, 3- And methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and more preferably 1,3-butanediol, 2-methyl-1,3-propanediol, and neopentyl glycol. 2,4-diethyl-1,5-pentanediol.

  If such a branched low molecular weight diol is used, in addition to transparency, the refractive index can be remarkably improved.

  These chain extenders can be used alone or in combination of two or more. In the present invention, the chain extender contains the above-described branched low molecular weight diol.

  The content of the branched low molecular weight diol is 5 to 45 mol%, preferably 10 to 40 mol%, more preferably 20 to 35 mol%, based on the total number of moles of the chain extender.

  If the content ratio of the branched low molecular weight diol is less than the above lower limit, the transparency and the refractive index are lowered.

  On the other hand, when the content ratio of the branched low molecular weight diol exceeds the above upper limit, the softening temperature, tackiness and impact resilience are lowered.

  The chain extender contains, for example, the above-described linear low molecular weight diol as the remainder of the branched low molecular weight diol.

  The content ratio of the linear low molecular weight diol is, for example, 55 to 95 mol%, preferably 60 to 90 mol%, more preferably 65 to 80 mol% with respect to the total number of moles of the chain extender. .

  When the content ratio of the linear low molecular weight diol is within the above range, transparency, softening temperature, tackiness, refractive index and rebound resilience can be improved.

  In the chain extender, for example, a carbon ring-containing low molecular weight diol can be used instead of the above-described linear low molecular weight diol.

  Examples of the carbocycle-containing low molecular weight diol include an aromatic ring-containing low molecular weight diol containing an aromatic ring and an alicyclic ring-containing low molecular weight diol containing an alicyclic ring.

  Examples of the aromatic ring-containing low molecular weight diol include aromatic ring-containing dihydric alcohols such as bishydroxyethoxybenzene, xylene glycol, bishydroxyethylene terephthalate, and bisphenol A.

  Examples of the alicyclic low molecular weight diol include alicyclic dihydric alcohols such as cyclohexanedimethanol and hydrogenated bisphenol A.

  These carbocycle-containing low molecular weight polyols can be used alone or in combination of two or more.

  In the present invention, a crosslinking agent can be used together with the polyisocyanate, the high molecular weight polyol and the chain extender.

  The crosslinking agent is an organic compound having a number average molecular weight of 40 to 800 having three or more active hydrogens, for example, a low molecular weight polyol having three or more hydroxyl groups, an aromatic polyamine, an araliphatic polyamine, an alicyclic polyamine, Examples include aliphatic polyamines.

  Examples of the low molecular weight polyol having three or more hydroxyl groups include the above-described 3 to 8 valent alcohols.

  Examples of the aromatic polyamine include 4,4′-diphenylmethanediamine, 3,3′-dichloro-4,4′-diphenylmethanediamine, Etacure 300 (trade name: manufactured by Albemarle), and TCCAM (trade name: Ihara Chemical Co., Ltd.). Manufactured).

  Examples of the araliphatic polyamine include 1,3- or 1,4-xylylenediamine or a mixture thereof.

  Examples of the alicyclic polyamine include 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis- (4-aminocyclohexyl) methane, diaminocyclohexane, and 3,9-bis (3-aminopropyl). ) -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3- and 1,4-bis (aminomethyl) cyclohexane and mixtures thereof, 1,3- and 1,4-bis (Aminoethyl) cyclohexane and mixtures thereof.

  Examples of the aliphatic polyamine include ethylenediamine, propylenediamine, pentamethylenediamine, hexamethylenediamine, hydrazine, 1,2-diaminoethane, 1,2-diaminopropane, 1,3-diaminopentane, and the like.

  These crosslinking agents can be used alone or in combination of two or more.

  The blending ratio of the cross-linking agent is appropriately set according to the purpose and application within a range not inhibiting the excellent effect of the present invention.

  The polyurethane elastomer of the present invention comprises the above-described components (ie, polyisocyanate, high molecular weight polyol and chain extender as essential components, monoisocyanate and / or crosslinker as optional components), for example, one-shot method or It can be obtained by reacting by a known method such as a prepolymer method.

  In any of the above methods, it is preferable that the high molecular weight polyol be subjected to a heat-reduced pressure dehydration treatment in advance to reduce its water content. The water content of the high molecular weight polyol after the treatment is, for example, 0.05% by mass or less, and preferably 0.03% by mass or less. More preferably, it is 0.02 mass% or less.

  In the one-shot method, polyisocyanate (further, if necessary, monoisocyanate), high molecular weight polyol and chain extender (further, if necessary, crosslinker), high molecular weight polyol and chain extender (and, if necessary, crosslinker) The equivalent ratio (isocyanate group / active hydrogen group (and amino group)) of the isocyanate group of polyisocyanate (and optionally monoisocyanate) to the active hydrogen group is, for example, 0.9 to 1.2, They are simultaneously blended and stirred and mixed at a ratio of 0.95 to 1.1, more preferably 0.98 to 1.08.

  In this reaction, the equivalent ratio of the isocyanate group of the polyisocyanate to the active hydrogen group of the high molecular weight polyol is 2 to 6, preferably 2.2 to 5.5, and more preferably 2.5 to 5.

  In addition, this stirring and mixing is performed, for example, in an inert gas (for example, nitrogen) atmosphere at a reaction temperature of 40 to 280 ° C., preferably 100 to 260 ° C., for a reaction time of about 30 seconds to 1 hour.

  The method for stirring and mixing is not particularly limited, but for example, a mixing tank such as a disper, a dissolver, a turbine blade, a circulating low-pressure or high-pressure collision mixing device, a high-speed stirring mixer, a static mixer, a kneader, a single screw or a twin screw Examples thereof include a method of stirring and mixing using a known mixing apparatus such as a rotary extruder and a belt conveyor type. Preferably, polyisocyanate (and optionally monoisocyanate), high molecular weight polyol and chain extender (and optionally crosslinker) are thoroughly mixed in a high speed stirring mixer, then static mixer, single screw extrusion A reaction mixture in which polyisocyanate (and monoisocyanate, if necessary), high molecular weight polyol and chain extender (and, if necessary, crosslinking agent) are sufficiently mixed using a high-speed stirring mixer. Is continuously flowed on a belt conveyor and allowed to react. If each component is stirred and mixed by such a method, generation | occurrence | production of the external appearance defect (for example, blister etc.) and gelation of the polyurethane elastomer obtained can be reduced.

  Further, at the time of stirring and mixing, a catalyst such as amines and metal compounds and a solvent can be added as necessary.

  The catalyst is preferably an organometallic compound. Examples of such an organometallic compound include a tin-based catalyst (for example, tin acetate, tin octylate (stannous octylate), tin oleate, lauric acid). Tin, dibutyltin diacetate, dimethyltin dilaurate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dichloride, etc.), lead-based catalysts (eg, lead octoate, lead naphthenate, etc.), eg, nickel naphthenate, cobalt naphthenate , Copper octenoate, bismuth-based catalysts, and the like.

  These catalysts can be used alone or in combination of two or more. For example, for a total amount of 1000 parts by mass of the high molecular weight polyol and the chain extender (and, if necessary, the crosslinking agent), for example, 0.001 to 0.00. 5 parts by mass, preferably 0.01 to 0.3 parts by mass are added.

  Examples of the solvent include aliphatic hydrocarbons such as n-hexane and octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. For example, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene, for example, alkyl esters such as methyl acetate, ethyl acetate, butyl acetate, and isobutyl acetate, such as ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, Glycol ether esters such as 3-methyl-3-methoxybutyl acetate and ethyl-3-ethoxypropionate, for example, ethers such as diethyl ether, tetrahydrofuran and dioxane Halogenated aliphatic hydrocarbons such as, for example, methyl chloride, methylene chloride, chloroform, carbon tetrachloride, methyl bromide, methylene iodide, dichloroethane, such as N-methylpyrrolidone, dimethylformamide, N, N′-dimethyl Examples include polar aprotic compounds such as acetamide, dimethyl sulfoxide, hexamethylphosphonilamide and the like.

  These solvents can be used alone or in combination of two or more, and are blended at an appropriate ratio depending on the viscosity of the reaction system.

  In the prepolymer method, first, an isocyanate group-terminated prepolymer is synthesized with a polyisocyanate (and, if necessary, a monoisocyanate) and a high molecular weight polyol to synthesize an isocyanate group-terminated prepolymer, and then a chain extender ( Further, a cross-linking agent) is reacted if necessary.

  In the synthesis of the prepolymer, the equivalent ratio of the isocyanate group of the polyisocyanate to the active hydrogen group of the high molecular weight polyol is 2 to 6, preferably 2.2 to 5.5, more preferably 2.5 to 5. is there.

  In addition, the above prepolymerization reaction is performed, for example, in an inert gas (eg, nitrogen) atmosphere at a reaction temperature of 40 to 150 ° C., for a reaction time of about 30 seconds to 8 hours, and for polyisocyanate (and, if necessary, monoisocyanate) And high molecular weight polyol are mixed with stirring. In addition, the above-described catalyst and solvent can be added to this reaction as necessary.

  Next, the isocyanate group-terminated prepolymer and the chain extender (and optionally a cross-linking agent) are combined with an equivalent ratio of the isocyanate group of the isocyanate group-terminated prepolymer to the active hydrogen group of the chain extender (and optionally the cross-linking agent) ( Isocyanate group / active hydrogen group (and amino group)) is, for example, 0.9 to 1.2, preferably 0.95 to 1.1, and more preferably 0.98 to 1.08. For example, the mixture is stirred and mixed by the stirring and mixing method described in the one-shot method.

  In this stirring and mixing, for example, the reaction temperature is 40 to 280 ° C., preferably 50 to 270 ° C., more preferably 60 to 260 ° C. If necessary, the above catalyst and solvent are added, and the reaction time is 0.5 minutes. Perform for about 30 minutes.

  Next, the stirred reaction mixture is exposed to, for example, 80 to 180 ° C. for 10 to 30 hours under a nitrogen stream and annealed.

  Thereby, the reaction completion degree can be improved, and as a result, a polyurethane elastomer having excellent mechanical properties can be obtained.

  As a method for synthesizing such a polyurethane elastomer, a prepolymer method is preferable from the viewpoint of improving mechanical properties.

  Moreover, such a polyurethane elastomer can further contain a bluing agent.

  The bluing agent is an additive (dye, pigment) that adjusts the hue by absorbing light in the wavelength range of, for example, orange to yellow in the visible light region. For example, ultramarine, bitumen, cobalt blue, etc. Inorganic dyes and pigments such as organic dyes and pigments such as phthalocyanine-based bluing agents and condensed polycyclic bluing agents (for example, indigo bluing agents and anthraquinone bluing agents). .

  The bluing agent is preferably a condensed polycyclic bluing agent, more preferably an anthraquinone bluing agent.

  An anthraquinone-based bluing agent is a bluing agent containing an anthraquinone ring represented by the following formula (1) and is not particularly limited, and examples thereof include a compound represented by the following formula (2).

  Such anthraquinone-based bluing agents are also available as commercial products. Examples of such commercially available products include Plast Blue 8510, Plast Blue 8514, Plast Blue 8516, Plast Blue 8520, and Plast Blue 8540. , Plast Blue 8580, Plast Blue 8590 (all of which are manufactured by Arimoto Chemical Industry Co., Ltd.), for example, Macrolex Violet B, Macrolex Violet 3R, Macrolex Blue RR (all of which are manufactured by Bayer) Dialresin Blue B, Dialresin Violet D, Dialresin Blue J, Dialresin Blue N (all of which are manufactured by Mitsubishi Chemical Corporation), for example, Sumiplast Violet B (Manufactured by Sumitomo Chemical Co., Ltd.).

  Preferred examples of these bluing agents include Plast Blue 8510, Plast Blue 8514, Plast Blue 8516, Plast Blue 8520, Plast Blue 8540, Plast Blue 8580, and Plast Blue 8590, and more preferred are Plu Blue 8590. .

  In the case where the polyurethane elastomer contains a bluing agent, the content of the bluing agent is, for example, 0.1 to 5 ppm, preferably 0 with respect to the total amount of the polyurethane elastomer (including the bluing agent). .2 to 3 ppm.

  For polyurethane elastomers, other known additives, for example, antioxidants, heat stabilizers, ultraviolet absorbers, light stabilizers, and plasticizers, antiblocking agents, mold release agents, as necessary. Pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, fillers, and the like can be added. These additives may be added at the time of synthesizing each component, or may be added at the time of mixing each component.

  The antioxidant is not particularly limited, and examples thereof include known antioxidants (for example, described in the catalog made by BASF Japan). More specifically, for example, hindered phenol compounds, phosphite compounds, Examples include thioether compounds.

  The heat stabilizer is not particularly limited, and may be a known heat stabilizer (for example, described in the catalog made by BASF Japan). More specifically, for example, phosphorus processing heat stabilizer, lactone processing heat. Stabilizers, sulfur processing heat stabilizers and the like.

  The ultraviolet absorber is not particularly limited and includes known ultraviolet absorbers (for example, described in the catalog made by BASF Japan), and more specifically, for example, benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers. Agents, benzophenone ultraviolet absorbers and the like.

  The light-resistant stabilizer is not particularly limited, and examples thereof include known light-resistant stabilizers (for example, described in a catalog manufactured by ADEKA). More specifically, for example, benzoate-based light stabilizers, hindered amine-based light stabilizers, and the like. Is mentioned.

  These additives (antioxidants, heat stabilizers, ultraviolet absorbers, light stabilizers) are each, for example, 0.01 to 1.2% by mass, preferably 0.1 to 1% by mass with respect to the polyurethane elastomer. It is added at a rate of%.

  And the parallel light transmittance of the polyurethane elastomer (thickness 200 μm) thus obtained is, for example, 90% or more, preferably 90.5% or more from the viewpoint of ensuring sufficient transparency.

  From the same viewpoint, the total light transmittance of the polyurethane elastomer (thickness: 200 μm) is, for example, 91% or more, preferably, 91.5% or more, and the diffused light transmittance is, for example, 2% or less, preferably Is 1.5% or less, and haze (turbidity) is, for example, 3 or less, preferably 2 or less.

Incidentally, the parallel light transmittance (JIS K7105 _(source: compliant _{D 65)),} the total light transmittance (JIS K7361-1 _(source: compliant _{D 65)),} diffuse light transmittance (JIS K7105 (light _{source: D 65} )) And haze (based on JIS K7136 (light source: D ₆₅ )) can be measured by a turbidity / cloudiness meter (for example, Haze Meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.)).

  The softening temperature of the polyurethane elastomer is, for example, 130 ° C. or higher, preferably 135 ° C. or higher, more preferably 140 ° C. or higher, and usually 200 ° C. or lower, from the viewpoint of improving processability.

In addition, the initial yellowness (b ^* ) of the polyurethane elastomer is, for example, 0.2 or less, preferably 0.15 or less, from the viewpoint of ensuring the transparency of the molded product (described later) and design.

  Further, the color difference (ΔE) of the polyurethane elastomer of the present invention before and after the heat resistance test (exposure conditions: 120 ° C., 100 hours) or the heat and humidity resistance test (exposure conditions: 70 ° C., 95% RH, 100 hours) is For example, it is 0.2 or less, preferably 0.15 or less.

  When the color difference (ΔE) is in the above range, yellowing of the polyurethane elastomer and the molded product (described later) can be reduced, and excellent transparency and design can be ensured over a long period of time.

The initial yellowness (b ^* ) of the polyurethane elastomer and the color difference (ΔE) before and after the heat resistance test or the heat resistance test are measured by a color measuring device (for example, SM color computer SM-T (manufactured by Suga Test Instruments Co., Ltd.)) ).

  The refractive index of the polyurethane elastomer is, for example, 1.500 or more, preferably 1.510 or more, and more preferably 1.530 or more.

  If the refractive index is in the above range, for example, a molded article having a high refractive index can be obtained. Therefore, it is useful as a component of an electronic / electrical material that requires optical characteristics. Furthermore, since the curvature of the molded product can be reduced, the thickness of the molded product can be reduced.

The refractive index of polyurethane elastomer (conforming to JIS K7105 (light source: incandescent lamp)) is determined by, for example, measuring the molded product with a refractometer (for example, Abbe refractometer 1 _T (manufactured by ATAGO)). Can be sought.

  In addition, the rebound resilience of the polyurethane elastomer is, as will be described later, in the case where the polyurethane elastomer is molded as a light guide film or a light guide sheet, from the viewpoint of favorably maintaining the key operability such as the click feeling, for example, 50% or more, preferably 52% or more, and more preferably 55% or more.

  The impact resilience can be measured according to a test method for JIS K-7311 polyurethane-based thermoplastic elastomer.

  And according to such a polyurethane elastomer of this invention, while being able to ensure the outstanding heat resistance, since tack property can be suppressed, the outstanding workability | operativity and operativity can be ensured.

  Moreover, since the polyurethane elastomer of the present invention is excellent in transparency and yellowing resistance, it is also excellent in design.

  Therefore, according to the polyurethane elastomer of the present invention, a molded product requiring optical characteristics and design properties can be formed with good workability and used.

  The present invention includes a molded article in which the above-described polyurethane elastomer of the present invention is used.

  For example, the above-mentioned polyurethane elastomer may be molded by a known molding method, for example, a thermoforming method such as heat compression molding and injection molding using a specific mold, or extrusion molding using a sheet winding device. For example, it can be obtained by molding into various shapes such as pellets, plates, fibers, strands, films, sheets, pipes, hollows, boxes, and the like.

  In thermoforming, other resins can be used together with the polyurethane elastomer as long as the effects of the present invention are not impaired.

  Examples of other resins include ionomer resins, transparent resins, and diene block copolymers.

  As an ionomer resin, for example, a polymer obtained by neutralizing at least a part of a carboxyl group in a copolymer of ethylene and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms with a metal ion, for example, ethylene Polymers in which at least a part of carboxyl groups in a ternary copolymer of an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α, β-unsaturated carboxylic acid ester are neutralized with a metal ion, etc. Can be mentioned.

  The α, β-unsaturated carboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and crotonic acid.

  These α, β-unsaturated carboxylic acids can be used alone or in combination of two or more.

  Preferred examples of the α, β-unsaturated carboxylic acid include acrylic acid and methacrylic acid.

  Examples of the α, β-unsaturated carboxylic acid ester include acrylic acid ester, methacrylic acid ester, fumaric acid ester, maleic acid ester, and more specifically, for example, acrylic acid, methacrylic acid, Examples thereof include fumaric acid and maleic acid, such as methyl ester, ethyl ester, propyl ester, n-butyl ester and isobutyl ester.

  These α, β-unsaturated carboxylic acid esters can be used alone or in combination of two or more.

  Preferred examples of the α, β-unsaturated carboxylic acid ester include acrylic acid esters and methacrylic acid esters.

  Further, a copolymer of ethylene and an α, β-unsaturated carboxylic acid or a carboxyl in a terpolymer of ethylene, an α, β-unsaturated carboxylic acid and an α, β-unsaturated carboxylic acid ester. Examples of the metal ion that neutralizes at least a part of the group include alkali metal ions such as sodium ion, potassium ion and lithium ion, for example, divalent ions such as magnesium ion, calcium ion, zinc ion, barium ion and cadmium ion. Metal ions, for example, trivalent metal ions such as aluminum ions, and other ions such as tin ions and zirconium ions.

  These metal ions can be used alone or in combination of two or more.

  As the metal ions, sodium ions, zinc ions, and magnesium ions are preferably used from the viewpoint of improving the impact resilience.

  These ionomer resins can be used alone or in combination of two or more.

  The ionomer resin is also available as a commercial product, and more specifically, for example, Himiran (trade name, Mitsui DuPont Polychemical Co.), Surlyn (trade name, DuPont), and the like.

  The transparent resin is not particularly limited, and examples thereof include a transparent polyamide elastomer, a transparent polyester elastomer, and a transparent polystyrene elastomer.

  These transparent resins can be used alone or in combination of two or more.

  Further, the transparent resin is also available as a commercial product. More specifically, for example, Pebax (transparent polyamide elastomer, trade name, Arkema), Hytrel (transparent polyester elastomer, trade name, Toray DuPont) and Lavalon (transparent polystyrene elastomer, trade name, Mitsubishi Chemical Corporation).

  Moreover, it does not restrict | limit especially as a diene type block copolymer, A well-known diene type block copolymer is mentioned.

  These other resins can be used alone or in combination of two or more.

  In the thermoforming, when the polyurethane elastomer and other resin are used in combination, the content ratio of the polyurethane elastomer is, for example, 50% by mass or more, preferably 60% by mass with respect to the total amount of the polyurethane elastomer and the other resin. % Or more, more preferably 70% by mass or more.

  In addition, as molding conditions of such a resin (the above-mentioned polyurethane elastomer as an essential component and other resins as an optional component), the molding temperature is, for example, 150 to 250 ° C., preferably 170 to 240 ° C. The molding pressure is, for example, 0.5 to 15 MPa, preferably 1 to 10 MPa.

  When the molding temperature and the molding pressure are in the above ranges, a molded product having excellent transparency can be obtained.

  The molded product thus obtained includes, for example, a light guide film, a light guide sheet, a key sheet for portable devices, a light guide plate for backlights of liquid crystal televisions and notebook computers, an in-vehicle lighting panel, a headlamp lens, and a taillight. Lamp covers, optical lenses for household appliances, optical disks, signboards, painting substitute films for building materials, optical fibers, sundries and packaging films, interlayer films for laminated glass, windshields for aircraft, furniture, system kitchens It is suitably used in various fields where optical properties are required, such as protective films for automobiles, chipping films for automobiles, crime prevention glass films, large tank walls, transparent roofing materials, contact lenses, and the like.

  In particular, the molded article is preferably molded and used as a light guide film or a light guide sheet.

  When the molded product is molded as a light guide film or a light guide sheet, the thickness thereof is, for example, 0.5 mm or less, preferably 0.4 mm or less, and more preferably 0.3 mm or less. In addition, although the minimum of thickness is not specifically limited, For example, it is 0.05 mm.

  And since the polyurethane elastomer of this invention is used for the molded article of this invention, it can be formed and used with sufficient workability | operativity, and the outstanding transparency and designability can be ensured.

  Therefore, the molded article of the present invention can be suitably used especially as an optical sheet such as a light guide film or a light guide sheet.

Next, although this invention is demonstrated based on a manufacture example, an Example, and a comparative example, this invention is not limited by the following Example. In the following description, “part” and “%” are based on mass unless otherwise specified. Moreover, the measuring method used for an Example etc. is shown below.
(Isocyanate group content / unit: mass% contained in the isocyanate group-terminated prepolymer solution)
The isocyanate group content of the isocyanate group-terminated prepolymer solution was measured by an n-dibutylamine method according to JIS K-1556 using a potentiometric titrator.

Production Example 1 (Production Method of 1,4-Bis (isocyanatomethyl) cyclohexane (hereinafter 1,4-BIC))
^A cold two-stage phosgenation method was carried out under pressure using 1,4-bis (aminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Inc.) having a trans / cis ratio of 85/15 as determined by ¹³ C-NMR measurement.

  2500 parts of orthodichlorobenzene was charged into a jacketed pressure reactor equipped with an electromagnetic induction stirrer, automatic pressure control valve, thermometer, nitrogen introduction line, phosgene introduction line, condenser and raw material feed pump. Next, 1425 parts of phosgene was added from the phosgene introduction line, and stirring was started. Cold water was passed through the reactor jacket to maintain the internal temperature at about 10 ° C. A solution prepared by dissolving 400 parts of 1,4-bis (aminomethyl) cyclohexane in 2500 parts of orthodichlorobenzene was fed with a feed pump over 60 minutes, and cold phosgenation was performed at 30 ° C. or lower and normal pressure. did. After the feed was completed, the inside of the flask became a pale brown white slurry.

  Next, the temperature in the reactor was increased to 140 ° C. over 60 minutes, the pressure was increased to 0.25 MPa, and thermal phosgenation was further performed at a reaction temperature of 140 ° C. for 2 hours. Further, 480 parts of phosgene were added during the thermal phosgenation. During the thermal phosgenation, the liquid in the flask became a light brown clear solution. After completion of the thermal phosgenation, nitrogen gas was aerated at 100 to 140 ° C. at 100 L / hour to degas.

  Next, after distilling off the solvent orthodichlorobenzene under reduced pressure, a glass flask was packed with 4 elements of packing (Sumitomo Heavy Industries, Ltd., trade name: Sumitomo / Sulzer Lab Packing EX type). Using a rectifying apparatus equipped with a tube, a distillation column equipped with a reflux ratio adjusting timer (manufactured by Shibata Kagaku Co., Ltd., trade name: distillation head K type) and a cooler, 138 to 143 ° C., 0.7 to 1 KPa Under the conditions, rectification was further performed while refluxing to obtain 382 parts of 1,4-BIC.

The purity of the obtained 1,4-BIC as measured by gas chromatography was 99.9%, the hue as measured by APHA was 5, and the trans / cis ratio as determined by ¹³ C-NMR was 85/15.

Example 1 (Preparation of polyurethane elastomer (A))
In a four-necked flask equipped with a stirrer, thermometer, reflux tube and nitrogen introduction tube, 348 parts of 1,4-BIC of Production Example 1 and polytetramethylene ether glycol having a number average molecular weight of 2000 (trade name: PTG2000SN, Hodogaya) 262 parts of Chemical Industry Co., Ltd. (hereinafter abbreviated as PTG2000SN) and 258 parts of polytetramethylene ether glycol (trade name: PTG1000, manufactured by Hodogaya Chemical Co., Ltd., hereinafter abbreviated as PTG1000) having a number average molecular weight of 1000 are charged. did. The mixture was heated to 80 ° C. with stirring, and reacted for 1 hour at the same temperature. Then, a tin-based catalyst solution (stannic octylate (trade name: Stanocto, manufactured by API Corporation)) was added to diisononyl adipate (trade name: DINA, Jay Plus). 5 ppm based on stannous octoate was added. Thereafter, the reaction was continued at the same temperature until the isocyanate group content reached 13.5% by mass to obtain an isocyanate group-terminated polyurethane prepolymer A (hereinafter abbreviated as prepolymer A). In this reaction, the equivalent ratio of the isocyanate groups of 1,4-BIC to the hydroxyl groups of PTG2000SN and PTG1000 was about 4.6.

  Subsequently, 0.3 parts of antioxidant (trade name: IRGANOX245, manufactured by BASF Japan) and phosphorus-based processing heat stabilizer (trade names: IRGAFOS38, BASF Japan) are added to 868 parts of prepolymer A adjusted to 80 ° C. in advance. 0.3 parts), 0.1 part UV absorber (trade name: Tinuvin 234, manufactured by BASF Japan), 0.1 part light stabilizer (trade name: ADK STAB LA-72, manufactured by ADEKA) and An anthraquinone-based bluing agent solution (a blueing agent (trade name: Plast Blue 8514, manufactured by Arimoto Chemical Industry Co., Ltd.) diluted to 0.1% by mass with DINA) Place in a stainless steel container temperature-controlled at ℃ and use a high-speed disperser to stir at 1000 rpm. If and mixed with stirring for approximately 3 minutes. Next, as a chain extender, neopentyl glycol (Tokyo Chemical Industry Co., Ltd., abbreviated as NPG) is added in advance to 88.5 parts of 1,4-butanediol (Mitsubishi Chemical Co., Ltd., abbreviated as 1,4-BD). A solution obtained by dissolving 43.9 parts at 80 ° C. was added, and the mixture was further stirred for about 10 minutes until the whole became uniform while adjusting the temperature to 80 ° C. to prepare a reaction mixture. The polyurethane elastomer A was synthesized by pouring the reaction mixture into a SUS vat whose temperature was adjusted to 150 ° C. in advance and reacting in an oven at 150 ° C. for 2 hours and then in an oven at 100 ° C. for 22 hours. Thereafter, the polyurethane elastomer A was removed from the vat and cured for one day under a constant temperature and humidity condition of a room temperature of 23 ° C. and a relative humidity of 50%.

The obtained polyurethane elastomer A was cut with a bale cutter and formed into pulverized pellets with a pulverizer. The pulverized pellets were dried overnight in an oven at 80 ° C. under a nitrogen stream. Subsequently, using a single-screw extruder (model: SZW20-25MG, manufactured by Technobel), strand molding was performed at a screw rotation speed of 30 rpm and a cylinder temperature of 150 to 250 ° C. to obtain polyurethane A pellets. The obtained pellets were dried overnight at 80 ° C. under a nitrogen stream, and then using a single screw extruder equipped with a T die, the screw rotation speed was 20 rpm, the cylinder temperature was 150 to 250 ° C., and the thickness was 200 μm. The film was formed as follows.

  The obtained film (thickness: 200 μm) was cured for 7 days under constant temperature and humidity conditions of room temperature 23 ° C. and relative humidity 50%.

Examples 2-8 and Comparative Examples 1-6
In the compounding formulations shown in Table 1 and Table 2, polyurethane elastomers B to N were synthesized by the same method as in Example 1.

  Moreover, the film (thickness 200 micrometers) was obtained by the method similar to Example 1 using obtained polyurethane elastomer BN.

  The polyurethane elastomers C, G, I, J, and N obtained in Examples 3 and 7 and Comparative Examples 1, 2, and 6 were dried in an oven at 80 ° C. under a nitrogen stream for 24 hours, and then injection molded. Machine (model: NEX-140, manufactured by Nissei Plastic Industrial Co., Ltd.), screw rotation speed 80 rpm, barrel temperature 150-250 ° C., mold temperature 30 ° C., injection time 10 seconds, injection speed 40-120 mm / second and Injection molding was performed under the condition of a cooling time of 45 seconds. Then, it was cured for 7 days under constant temperature and humidity conditions of room temperature 23 ° C. and relative humidity 50% to obtain a polyurethane sheet (thickness 2 mm).

  In Comparative Example 6, dicyclohexylmethane diisocyanate was used as the polyisocyanate. Dicyclohexylmethane diisocyanate is abbreviated as hydrogenated MDI.

  Further, 1,3-butanediol (manufactured by Wako Pure Chemical Industries), 2-methyl-1,3-propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2,4-diethyl-1,5 used as chain extenders -Pentanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) is abbreviated as 1,3-BD, 2-MPD and 2,4-DEPD, respectively.

Physical property evaluation 1
The parallel light transmittance, softening temperature, yellowness and tackiness of the polyurethane elastomers obtained in each Example and each Comparative Example were measured by the following methods. The results are shown in Tables 1 and 2.
<Parallel light transmittance (unit:%)>
Using a Haze Meter (manufactured by Nippon Denshoku Industries Co., Ltd., model: NDH 2000), the parallel light transmittance (based on JIS K7105 (light source: D ₆₅ )) of a 200 μm-thick polyurethane elastomer film was measured.
<Softening temperature (unit: ° C)>
Using a thermomechanical analyzer (Seiko Instruments, model: TMA / 6600), the softening temperature of the 200 μm-thick polyurethane elastomer film was measured by the method described in JIS K7196.
<Yellowness (b ^* )>
The initial yellowness (b ^* ) of the polyurethane elastomer film having a thickness of 200 μm was measured using an SM color computer (manufactured by Suga Test Instruments, model: SM-T).
<Tackiness>
After film formation, the film was allowed to stand for 24 hours at a room temperature of 23 ° C. and a relative humidity of 50%, and then the films were overlapped and allowed to stand for 1 minute. The state at the time of peeling was observed and evaluated as tackiness.

  In addition, the thing which can be peeled easily was set as (circle), the thing which adheres but can peel is (triangle | delta), and the thing which cannot adhere and cannot peel was set as x.

Physical property evaluation 2
The refractive index and Abbe number of the polyurethane sheets (thickness 2 mm) obtained in Examples 3 and 7 and Comparative Examples 1, 2 and 6 were measured by the following methods. The results are shown in Table 3.
<Refractive index and Abbe number>
Using a refractometer (manufactured by ATAGO, model: Abbe refractometer 1 _T ), a test piece of a polyurethane sheet of 10 mm × 20 mm × 2 mm manufactured by injection molding is used for the refractive index and Abbe number (JIS K7105 (light source: Incandescent lamp)).

Claims (9)

A polyurethane elastomer obtained by reacting at least a polyisocyanate, a high molecular weight polyol, and a chain extender,
The polyisocyanate contains 1,4-bis (isocyanatomethyl) cyclohexane;
The high molecular weight polyol is polytetramethylene ether glycol;
The chain extender contains a branched low molecular weight diol having 1 to 6 carbon atoms in the branched chain in a proportion of 5 to 45 mol% with respect to the total number of moles of the chain extender,
The polyurethane elastomer, wherein an equivalent ratio of an isocyanate group of the polyisocyanate to a hydroxyl group of the high molecular weight polyol is 2 to 6.   2. The polyurethane elastomer according to claim 1, wherein the parallel light transmittance is 90% or more.   The polyurethane elastomer according to claim 1 or 2, wherein the softening temperature is 130 ° C or higher.   The polyurethane elastomer according to any one of claims 1 to 3, wherein the branched low molecular weight diol has 1 to 5 carbon atoms in the branched chain.   The branched low molecular weight diol is 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentane. The polyurethane elastomer according to any one of claims 1 to 4, wherein the polyurethane elastomer is at least one selected from the group consisting of diol and 2,4-diethyl-1,5-pentanediol.   The polyurethane elastomer according to any one of claims 1 to 5, comprising an anthraquinone-based bluing agent in a proportion of 0.1 to 5 ppm.   A molded article, wherein the polyurethane elastomer according to claim 1 is used.   The molded article according to claim 7, which is molded as a light guide film.   The molded article according to claim 7, wherein the molded article is molded as a light guide sheet.