JP5464889B2 - Polycarbonate diol - Google Patents

Description

  The present invention relates to a polycarbonate diol suitable as a raw material for polyurethane, thermoplastic elastomer and the like, or as a constituent material for paint, adhesive and the like. More specifically, the present invention relates to a polycarbonate diol capable of obtaining a highly flexible polyurethane or thermoplastic elastomer.

  Polycarbonate diol is known as a material excellent in hydrolysis resistance, weather resistance, oxidation deterioration resistance, heat resistance and the like as a soft segment such as polyurethane and thermoplastic elastomer. However, polycarbonate diol using 1,6-hexanediol as a raw material has crystallinity, and polyurethane using this has a drawback of low flexibility and elastic recovery. In order to solve these problems, an aliphatic copolycarbonate diol is disclosed in which the regularity of the polycarbonate diol molecule is disturbed and the crystallinity is lowered by using a polyhydric alcohol having a side chain.

For example, a polycarbonate diol characterized by using a polyhydric alcohol having a side chain having 3 to 20 carbon atoms and 1,6-hexanediol as an aliphatic diol (see Patent Document 1). In the examples, neopentyl glycol, 3-methyl-1,5-pentanediol, and trimethyl-1,6-hexanediol are used as the polyhydric alcohol having a side chain.
Furthermore, as the polycarbonate diol using a polyhydric alcohol having one side chain, one using 2-methyl-1,3-propanediol as a main component (see Patent Document 2), 3-methyl-1,5- Those using pentanediol and 1,9-nonanediol (see Patent Document 3) and those using 2-methyl 1,8-octanediol and 1,9-nonanediol (see Patent Document 4) are disclosed. As polycarbonate diols using polyhydric alcohols substituted with two lower alkyl groups, those using 2,4-dialkyl-1,5-pentanediol (see Patent Document 5), 2,2-dialkyl- Those using 1,3-propanediol (see Patent Documents 6 and 7) are disclosed.

  When the polycarbonate diol obtained by the technique shown above is used, it has been difficult to improve the flexibility of the polyurethane and the thermoplastic elastomer to the target value. In addition, even when the flexibility was improved, new problems such as a decrease in strength occurred.

JP-A-2-49025 International Publication Number WO2006 / 088152 Japanese Patent No. 1719721 Japanese Patent No. 2506713 International Publication Number WO98 / 27133 JP 2008-533273 A JP 2000-336140 A

  An object of this invention is to provide the polycarbonate diol suitable as raw materials, such as a polyurethane and a thermoplastic elastomer, or as structural materials, such as a coating material and an adhesive agent. More specifically, an object of the present invention is to provide a polycarbonate diol capable of obtaining a highly flexible polyurethane or thermoplastic elastomer.

As a result of intensive studies to solve the above-mentioned problems, the present inventor efficiently reduces the regularity of the polycarbonate diol molecule by using a diol having a specific structure as a raw material, and reduces the mutual relationship between carbonate bonds. It has been found that flexible polyurethanes and thermoplastic elastomers can be obtained without suppressing the action and causing problems such as a decrease in strength, and the present invention has been made.
That is, the present invention relates to the following inventions (1) to (4).
(1) A polycarbonate diol comprising a repeating unit represented by the following formula (A) and a terminal hydroxyl group, wherein 70 to 100 mol% of the repeating unit represented by the formula (A) is represented by the following formula (B) or ( C) a repeating unit represented by
A polycarbonate diol, wherein the ratio of the above formulas (B) and (C) is 1:99 to 40:60 in terms of molar ratio, and the number average molecular weight is 300 to 10,000.
(2) The polycarbonate diol according to (1) above, wherein the repeating unit of the formula (C) is a repeating unit represented by the following formula (D).
(3) The polycarbonate diol as described in (1) or (2) above, wherein the initial flexibility index is from 0.10 to 0.85.
(4) The polycarbonate diol according to (3) above, wherein the strength index is 1.01 or more.

  The present invention provides a polycarbonate diol that is most suitable as a raw material for polyurethane, thermoplastic elastomer, and the like, or as a constituent material for paints, adhesives, and the like. More specifically, it has an effect of providing a polycarbonate diol capable of obtaining polyurethane and thermoplastic elastomer having high flexibility and strength.

Hereinafter, the present invention will be specifically described.
The polycarbonate diol of the present invention is obtained using 2,2-dialkyl-substituted-1,3-propanediol (hereinafter referred to as 2,2-substituted PDL) and an aliphatic diol having no side chain as raw materials.
In the present invention, the 2,2-substituted PDL is represented by the following formula (E): 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, -Pentyl-2-propyl-1,3-propanediol and the like.

  Examples of the aliphatic diol having no side chain include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1 , 8-octanediol, 1,9-nanodiol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol and the like. One or more diols can be selected and used from the 2,2-substituted PDL and the aliphatic diol having no side chain.

  Since 2,2-substituted PDL has a bulky structure in which two alkyl groups are bonded to one carbon, the regularity of the molecule is greatly reduced by introducing the structure into polycarbonate diol. Furthermore, since 2-butyl-2-ethyl-1,3-propanediol, 2-pentyl-2-propyl-1,3-propanediol, and the like have side chains with more carbon atoms than the main chain, Alternatively, the interaction between carbonate bonds in the molecule is likely to be inhibited. Due to the above effects, the polycarbonate diol using 2,2-substituted PDL as a raw material has high flexibility. Furthermore, the flexibility and strength of the resulting polyurethane or thermoplastic elastomer can be controlled by combining a 2,2-substituted PDL having a bulky structure with an aliphatic diol having no side chain. When 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol is used as the diol having no side chain, it is preferable because the balance between flexibility and strength is improved. Further, when 1,6-hexanediol is used, it is most preferable because it is possible to obtain a polyurethane and a thermoplastic elastomer that are flexible and have high breaking strength.

  Ratio of repeating units derived from 2,2-substituted PDL in the polycarbonate diol (the above formula (B)) and repeating units derived from a diol having no side chain (the above formula (C)) (hereinafter referred to as a copolymerization ratio). The above formula (B): represented by the above formula (C)) is 1:99 to 40:60 in a molar ratio. When the molar ratio of the repeating units derived from the 2,2-substituted PDL is 40 or less, the strength of the polyurethane or thermoplastic elastomer obtained by using the polycarbonate diol is preferably not insufficient. On the other hand, when the molar ratio of the repeating unit derived from the 2,2-substituted PDL is 1 or more, the flexibility is improved, which is preferable. When the copolymerization ratio is 3:97 to 25:75, it is preferable because a flexible polyurethane having high strength and a thermoplastic elastomer can be obtained. When it is 5:95 to 15:85, high flexibility and high are obtained. This is most preferable because a polyurethane and a thermoplastic elastomer having high strength can be obtained.

  Furthermore, 2-methyl-1,8-octanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4- Diols having side chains such as dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, 2 One or two or more diols can be selected and used as a raw material from cyclic diols such as -bis (4-hydroxycyclohexyl) -propane. The amount is 30 mol% or less based on the total amount of the 2,2-substituted PDL and the aliphatic diol having no side chain. If it exceeds 30%, the strength of the resulting polyurethane or thermoplastic elastomer is lowered, or the flexibility is lowered.

  A small amount of a compound having three or more hydroxyl groups per molecule, for example, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol and the like can be used. When too many compounds having three or more hydroxyl groups in one molecule are used, gelation occurs due to crosslinking during the polymerization reaction of the polycarbonate. Therefore, the compound having 3 or more hydroxyl groups in one molecule is preferably 0.1 to 5 mol% based on the total amount of 2,2-substituted PDL and aliphatic diol having no side chain. More preferably, it is 0.1-2 mol%, More preferably, it is 0.1-0.5 lu%.

  By using the polycarbonate diol of the present invention, flexible polyurethane or thermoplastic elastomer can be obtained. In the present invention, flexibility is expressed using an initial flexibility index. The initial flexibility index was determined by the following method. The polycarbonate diol was dried under reduced pressure at 100 ° C. for 1 hour at 50 kPa or less. 0.1 mol of polycarbonate diol and 0.15 mol of 1,4-butanediol are dissolved in 600 kg of dimethylformamide (DMF), 0.2 mol of 4,4′-diphenylmethane diisocyanate (MDI) is added, and the mixture is heated at 80 ° C. The reaction was performed for 6 hours to obtain a DMF solution of polyurethane. The obtained polyurethane DMF solution was cast on a glass plate and dried to obtain a film having a thickness of 0.07 to 0.10 mm. This film was cut into a 10 mm × 80 mm strip and cured in a thermostatic chamber at 23 ° C. and 50% RH for 5 days. In a temperature-controlled room at 23 ° C. and 50% RH, a tensile test of the specimen was performed using a Tensilon tensile tester (ORIENTEC, RTC-1250A) at a chuck distance of 50 mm and a tensile speed of 100 mm / min. The Young's modulus was determined from the initial slope in the quantity-tensile stress curve.

A polycarbonate diol obtained by polymerizing only 1,6-hexanediol as a diol raw material (hereinafter referred to as C6 homoPCD) was defined as an initial flexibility index as a ratio to Young's modulus obtained by the above method (the following mathematical formula) 1). Each sample was measured five times, and the initial flexibility index was calculated using the average value. The molecular weight of the C6 homo PCD used was selected so that the molecular weight of the polycarbonate diol to be evaluated was within ± 2% of the molecular weight of the C6 homo PCD.
Initial flexibility index = B / A (1)
A: Young's modulus obtained using C6 homo PCD B: Young's modulus obtained using polycarbonate diol other than C6 homo PCD

  The soft feel correlates with the initial stress of the polyurethane. A feeling that the smaller the initial stress is, the more flexible it is. In general, the lower the Young's modulus, that is, the smaller the initial flexibility index, the higher the flexibility of the polyurethane using C6 homo PCD, which is said to be insufficient in flexibility. Usually, if the initial flexibility index is 0.10 or more and 0.85 or less, a flexible polyurethane or thermoplastic elastomer can be obtained. If the initial flexibility index is 0.85 or less, the flexibility is sufficient, and if it is 0.10 or more, the initial stress is not too small, and it may not be practically used depending on the application. If the initial flexibility index is 0.20 or more and 0.80 or less, it is more preferable, and if it is 0.30 or more and 0.60 or less, it is most preferable because a highly flexible polyurethane or thermoplastic elastomer can be obtained. .

On the other hand, tough polyurethanes and thermoplastic elastomers are also required. In the present invention, the toughness of the obtained polyurethane or thermoplastic elastomer is represented by a strength index. The strength index of the present invention was expressed by the following mathematical formula (2) using the breaking strength in the tensile test conducted to obtain the initial flexibility index. In addition, the breaking strength used the average value measured 5 times.
Strength index = D / C (2)
C: Break strength obtained using C6 homo PCD D: Break strength obtained using polycarbonate diol other than C6 homo PCD When strength index is 0.75 or more, when used as polyurethane or thermoplastic elastomer Sufficient strength can be obtained. A strength index of 1.01 or more is preferable because a tough polyurethane or thermoplastic elastomer can be obtained, and a strength index of 1.10 or more is more preferable.
In the case of having both the initial flexibility index and the strength index of the present invention, it is possible to obtain polyurethane and thermoplastic elastomer having both toughness in addition to flexibility.

The method for producing the polycarbonate diol of the present invention is not particularly limited. For example, it can be produced by various methods described in Schnell, Polymer Reviews, Vol. 9, p9-20 (1994).
The polycarbonate diol of the present invention includes, as carbonates, dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate, diaryl carbonates such as diphenyl carbonate, ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1, Examples thereof include alkylene carbonates such as 2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. Among these, one or more carbonates can be used as a raw material. From the viewpoint of availability and ease of setting the polymerization reaction conditions, it is preferable to use dimethyl carbonate, diethyl carbonate, diphenyl carbonate, or dibutyl carbonate.

  In the production of the polycarbonate diol of the present invention, a catalyst may or may not be added. When adding a catalyst, it can select freely from a normal transesterification catalyst. For example, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium and other metals, salts, alkoxides, organic compounds Used. Particularly preferred are titanium, tin and lead compounds. Moreover, the usage-amount of a catalyst is 0.00001 to 0.1% of polycarbonate diol weight normally.

In the polycarbonate diol of the present invention, the molecular weight is 300 to 10,000 in terms of number average molecular weight. When the number average molecular weight is 300 or more, the thermoplastic polyurethane obtained has good flexibility and low-temperature characteristics, and when it is 10,000 or less, the molding processability of the obtained thermoplastic polyurethane is not lowered. The number average molecular weight is preferably in the range of 450 to 5000. More preferably, it is 500-3000.
The paint and thermoplastic polyurethane can be obtained using the polycarbonate diol and polyisocyanate of the present invention.

  Examples of the polyisocyanate used include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixtures thereof (TDI), crude TDI, diphenylmethane-4,4′-diisocyanate (MDI), crude MDI, Known aromatic diisocyanates such as naphthalene-1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-biphenylene diisocyanate, polymethylene polyphenyl isocyanate, xylylene diisocyanate (XDI), phenylene diisocyanate, 4 , 4'-methylenebiscyclohexyl diisocyanate (hydrogenated MDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), cyclohexane diisocyanate (hydrogenated XDI), etc. Aliphatic diisocyanates known, and these isocyanates isocyanurate-modified products, carbodiimide-modified products, a biuretization modified products. These organic polyisocyanates may be used alone or in combination of two or more. These organic polyisocyanates may be used by masking isocyanate groups with a blocking agent.

  If desired, a chain extender can be used as a copolymerization component. As the chain extender, a chain extender commonly used in the polyurethane industry, that is, water, a low molecular polyol, a polyamine and the like can be used. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,10-decanediol, 1,1-cyclohexanedi Low molecular polyols such as methanol, 1,4-cyclohexanedimethanol, xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxyphenyl) propane, ethylenediamine, hexamethylenediamine, isophoronediamine, xylylenediamine, diphenyl Polyamines such as diamine and diaminodiphenylmethane. These chain extenders may be used alone or in combination of two or more.

As a method for producing a paint, a production method known in the industry is used. For example, a two-component solvent-based coating composition in which a main component composed of polycarbonate diol and a curing agent composed of organic polyisocyanate are mixed immediately before coating, and urethane having isocyanate end groups obtained by reacting polycarbonate diol and organic polyisocyanate. One-component solvent-based coating composition comprising a prepolymer, one-component solvent-based coating composition comprising a polyurethane resin obtained by reacting a polycarbonate diol, an organic polyisocyanate and a chain extender, or a one-component aqueous coating composition Can be manufactured.
Curing accelerators (catalysts), fillers, dispersants, flame retardants, dyes, organic or inorganic pigments, mold release agents, fluidity modifiers, plasticizers, antioxidants, UV absorbers, light stability depending on various applications An agent, an antifoaming agent, a leveling agent, a colorant, a solvent and the like can be added.

  Solvents include dimethylformamide, diethylformamide, dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, acetone, methyl ethyl ketone, methyl isobutyl ketone, dioxane, cyclohexanone, benzene, toluene, xylene, ethyl cellosolve, ethyl acetate, butyl acetate, ethanol, isopropanol, n -One kind selected from butanol, water, or a mixture of a plurality of solvents.

As a method for producing the thermoplastic polyurethane, a technique of polyurethane reaction known in the polyurethane industry is used. For example, a thermoplastic polyurethane can be produced by reacting the polycarbonate diol of the present invention with an organic polyisocyanate under atmospheric pressure from room temperature to 200 ° C. When a chain extender is used, it may be added from the beginning of the reaction or may be added from the middle of the reaction. For the method for producing thermoplastic polyurethane, reference can be made, for example, to US Pat. No. 5,070,173.
In the polyurethane reaction, a known polymerization catalyst or solvent may be used.
It is desirable to add a stabilizer such as a heat stabilizer (for example, an antioxidant) or a light stabilizer to the thermoplastic polyurethane. Further, a plasticizer, an inorganic filler, a lubricant, a colorant, silicon oil, a foaming agent, a flame retardant, and the like may be added.

The number average molecular weight of the present invention is determined by determining the hydroxyl value by the “neutralization titration method (JIS K 0070-1992)” in which acetic anhydride and pyridine are used and titrated with an ethanol solution of potassium hydroxide. Used to calculate.
Number average molecular weight = 2 / (OH value × 10 ⁻³ /56.1) (3)

  The copolymerization ratio in the present invention was determined by the following method. 1 g of a sample is taken into a 100 ml eggplant flask, 30 g of ethanol and 4 g of potassium hydroxide are added, and reacted at 100 ° C. for 1 hour. After cooling to room temperature, add 2-3 drops of phenolphthalein to the indicator and neutralize with hydrochloric acid. After cooling in the refrigerator for 1 hour, the precipitated salt was removed by filtration, and using GC, 2,2-substituted PDL derived from the repeating unit (B) below and diol derived from the following formula (C) were quantified. GC analysis was performed using gas chromatography GC-14B (manufactured by Shimadzu Corporation, Japan) with DB-WAX (manufactured by J & W, USA) as a column, diethylene glycol diethyl ester as an internal standard, and a detector as FID. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min. The copolymerization ratio was determined by using the result obtained by the above method, and the molar ratio of 2,2-substituted PDL and aliphatic diol having no side chain (number of moles of 2,2-substituted PDL: having side chain) The total number of moles of aliphatic diols).

The ratio of the repeating unit represented by the above formula (B) or (C) in the repeating unit represented by the above formula (A) (hereinafter referred to as the main component ratio) is a method for obtaining a copolymerization ratio. Was obtained by the following mathematical formula (4) based on the obtained GC analysis result.
Main component ratio (mol%) = (E + F) / G × 100 (4)
E: Number of moles of 2,2-substituted PDL derived from the repeating unit of formula (B) F: Total number of moles of diol derived from the repeating unit of formula (C) G: Total number of moles of diol The invention is illustrated by examples and comparative examples.

[Example 1]
In a 2 L glass flask equipped with a rectification column packed with a regular packing and a stirrer, 660 g (7.5 mol) of ethylene carbonate, 65 g of 2-butyl-2-ethyl-1,3-propanediol (0. 4 mol) and 850 g (7.2 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, and the mixture was stirred and heated at normal pressure. The reaction was carried out at a reaction temperature of 140 ° C. to 150 ° C. and a pressure of 3.0 to 5.0 kPa for 20 hours while distilling off the resulting mixture of ethylene glycol and ethylene carbonate. Thereafter, the pressure was reduced to 0.5 kPa, and the reaction was further carried out at 150 to 160 ° C. for 10 hours while distilling off ethylene carbonate and diol. When the obtained copolymer polycarbonate diol was analyzed, the number average molecular weight was 1987 and the copolymerization ratio was 4:96.

[Example 2]
In Example 1, the same apparatus was used except that the amount of 2-butyl-2-ethyl-1,3-propanediol was 175 g (1.1 mol) and 1,6-hexanediol was 790 g (6.8 mol). The reaction was carried out under the same conditions. When the obtained copolymer polycarbonate diol was analyzed, the number average molecular weight was 2016, and the copolymerization ratio was 11:89.

[Example 3]
In Example 1, the same apparatus was used except that the amount of 2-butyl-2-ethyl-1,3-propanediol was 330 g (2.1 mol) and 1,6-hexanediol was 700 g (5.9 mol). The reaction was carried out under the same conditions. When the obtained copolymer polycarbonate diol was analyzed, the number average molecular weight was 1978, and the copolymerization ratio was 21:79.

[Example 4]
In Example 1, the same apparatus was used except that the amount of 2-butyl-2-ethyl-1,3-propanediol was 445 g (2.8 mol) and 1,6-hexanediol was 650 g (5.5 mol). The reaction was carried out under the same conditions. When the obtained copolymer polycarbonate diol was analyzed, the number average molecular weight was 1992 and the copolymerization ratio was 27:73.

[Comparative Example 1]
660 g (7.5 mol) of ethylene carbonate, 660 g (7.3 mol) of 1,4-butanediol, 1,6-hexane in a 2 L glass flask equipped with a rectification column packed with a regular packing and a stirrer 130 g (1.1 mol) of diol was charged. As a catalyst, 0.120 g of titanium tetrabutoxide was added and stirred and heated at normal pressure. While gradually increasing the reaction temperature from 150 ° C. to 160 ° C., the reaction was carried out for 17 hours while distilling off the resulting mixture of ethylene glycol and ethylene carbonate. Thereafter, the pressure was reduced to 0.5 kPa, and the reaction was further carried out at 170 ° C. for 10 hours while distilling off the diol and ethylene carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 2005.

[Comparative Example 2]
In Comparative Example 1, 660 g (7.5 mol) of ethylene carbonate, 350 g (3.4 mol) of 1,5-pentanediol, and 490 g (4.2 mol) of 1,6-hexanediol were used as raw materials. The reaction was performed under the same conditions using the same apparatus. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1971.

[Comparative Example 3]
In Comparative Example 1, the reaction was performed under the same conditions using the same apparatus except that 660 g (7.5 mol) of ethylene carbonate and 775 g (8.6 mol) of 1,4-butanediol were used as raw materials. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1982.
Table 1 below shows the results of obtaining the initial flexibility index and the strength index for the polycarbonate diols of the above Examples and Comparative Examples. The molecular weight of C6 homo PCD used for evaluation was 1983.

  It can be used as a raw material such as polyurethane or thermoplastic elastomer having high flexibility, or as a constituent material such as paint or adhesive.

Claims (4)

A polycarbonate diol comprising a repeating unit represented by the following formula (A) and a terminal hydroxyl group, wherein 70 to 100 mol% of the repeating unit represented by the formula (A) is represented by the following formula (B) or (C): A repeating unit represented, and
A polycarbonate diol, wherein the ratio of the above formulas (B) and (C) is 1:99 to 40:60 in terms of molar ratio, and the number average molecular weight is 300 to 10,000. The polycarbonate diol according to claim 1, wherein the repeating unit of the formula (C) is a repeating unit represented by the following formula (D).
  The polycarbonate diol according to claim 1 or 2, wherein an initial flexibility index is 0.10 or more and 0.85 or less.   The polycarbonate diol according to claim 3, wherein the strength index is 1.01 or more.