JPWO2015064578A1 - Polyurethane composition for watch and watch using the same - Google Patents

Abstract

[Problem] To provide a polyurethane composition capable of producing a watch band which is not easily deteriorated and can be used for a long period of time. Also, an environment-friendly polyurethane composition is provided in which waste generated during injection molding can be reused in the manufacture of watch bands. [Solution] The polyurethane composition for watches of the present invention comprises a specific structural unit (a1) derived from diisocyanate, a specific structural unit (a2-1) derived from diol, and a specific structural unit (a2-2). ) And (a2-3) in a specific amount, a polyurethane component (A), an ultraviolet absorber (B1), a hindered phenol antioxidant (B2), a phosphorus stabilizer ( B3), an additive (B) comprising a hindered amine stabilizer (B4) and a carbodiimide rebinding agent (B5).

Description

  The present invention relates to a timepiece polyurethane composition and a timepiece using the same.

  Conventionally, polyurethane compositions have been used as materials for watches, particularly watch bands. This polyurethane composition is usually composed of a polyester polyurethane obtained by polymerizing polyester diol and diisocyanate, or a polyether polyurethane obtained by polymerizing polyether diol and diisocyanate.

  For example, Patent Document 1 discloses a thermoplastic polyurethane obtained from a high molecular diol (A) containing a specific polyester diol, a low molecular diol (B) and an organic diisocyanate (C), an antioxidant, and an ultraviolet ray if necessary. A watch band using a thermoplastic polyurethane resin composition containing an additive such as an absorbent is disclosed.

JP-A-6-172482

  However, in a watch band using polyester polyurethane, sweat or water adheres during use, and the polyurethane ester group may hydrolyze after a certain period of time, resulting in tearing or cracking. In addition, a watch band using a polyether-based polyurethane is weak against heat and easily changes to yellow. Thus, the conventional watch band may deteriorate in a relatively short time.

  Further, when a watch band is manufactured from a conventional polyurethane composition by injection molding, waste called a runner is generated. Since this waste is reduced in strength or yellowed due to heating during injection molding, it is difficult to mix it with a new material of the polyurethane composition and reuse it for manufacturing a watch band.

  Accordingly, an object of the present invention is to provide a timepiece polyurethane composition capable of producing a timepiece band which is not easily deteriorated and can be used for a long time. Another object of the present invention is to provide a polyurethane composition for a watch that can be reused in the production of a watch band from the waste produced during injection molding, and is excellent from the environmental viewpoint.

  The polyurethane composition for timepieces according to the present invention includes a structural unit (a1) represented by the following general formula (a1) derived from diisocyanate and a structural unit (a2) represented by the following general formula (a2-1) derived from diol. -1), a structural unit (a2-2) represented by the following general formula (a2-2) derived from the diol and a structural unit (a2-3) represented by the following general formula (a2-3) derived from the diol Polyurethane component (A) comprising at least one selected from the group consisting of UV absorber (B1), hindered phenol antioxidant (B2), neutral phosphate ester (B3-1) and neutral phosphite ester It comprises at least one phosphorus stabilizer (B3) selected from (B3-2), a hindered amine stabilizer (B4) and a carbodiimide rebinding agent (B5). The polyurethane component (A) contains 10 to 25 structural units (a1) with respect to a total of 100 mol% of the structural units (a1) and (a2-1) to (a2-3). It is characterized by containing the mol unit, the structural unit (a2-1) in an amount of 50 to 85 mol%, and the total of the structural units (a2-2) and (a2-3) in an amount of 3 to 35 mol%.

（式（ａ１）中、Ｒ^a1は、炭素原子数３〜８の２価の飽和脂肪族炭化水素基を表す。）

(In the formula (a1), R ^a1 represents a divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms.)

（式（ａ２−１）中、Ｒ^a21は、炭素原子数４〜１０の２価の飽和脂肪族炭化水素基を表す。）

(In formula (a2-1), R ^a21 represents a divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms.)

（式（ａ２−２）中、Ｒ^a22は、炭素原子数３〜６の２価の飽和脂肪族炭化水素基を表す。）

(In formula (a2-2), R ^a22 represents a divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms.)

（式（ａ２−３）中、Ｒ^a23は、炭素原子数２〜６の２価の飽和脂肪族炭化水素基を表す。）

(In formula (a2-3), R ^a23 represents a divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms.)

  According to the polyurethane composition for a watch according to the present invention, a watch band that is not easily deteriorated and can be used for a long time can be manufactured. Moreover, the polyurethane composition for timepieces according to the present invention can be reused for the production of a timepiece band from the waste produced at the time of injection molding, and is excellent from the viewpoint of environment.

Hereinafter, the present invention will be specifically described.
<Polyurethane composition for watches>
The polyurethane composition for a watch according to the present invention is characterized in that a polyurethane component (A) containing a specific structural unit in a specific amount and a specific additive (B) are combined. By this combination, it is possible to manufacture a watch band that can be used for a long period of time without being deteriorated by heat, light, water, or the like. In addition, waste such as runners generated during injection molding can be reused in the manufacture of watch bands. That is, as described above, the timepiece polyurethane composition according to the present invention is resistant to heat, and it is difficult to cause a decrease in strength or color change due to heating during injection molding. Can be mixed and reused for watchband manufacturing.

[Polyurethane component (A)]
The polyurethane component (A) used in the present invention is a structural unit represented by a specific general formula (a1) derived from a diisocyanate and a specific general formula (a2-1) derived from a diol. (A2-1), a structure represented by a specific general formula (a2-3) derived from a diol and a structural unit (a2-2) represented by a specific general formula (a2-2) derived from a diol A specific amount of at least one unit (a2-3) is included. Thereby, it becomes a polyurethane component which is excellent in balance of tensile strength, flexibility and resilience, and hardly deteriorates by heat, light and water. In the polyurethane component (A), the structural unit derived from diisocyanate is only the structural unit (a1), and the structural units derived from diol are only the structural units (a2-1) to (a2-3). Particularly preferred from the above viewpoint.

  Specifically, the structural unit (a1) derived from diisocyanate is represented by the following general formula (a1).

式（ａ１）中、Ｒ^a1は、炭素原子数３〜８の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン成分（Ａ）中に複数存在するＲ^a1は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ１）はＲ^a1が二重結合を含まないため、紫外線などの光によって劣化しがたい。

In the formula (a1), R ^a1 represents a divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms. A plurality of R ^a1 present in the polyurethane component (A) may all be the same or two or more may be mixed. The structural unit (a1) is unlikely to be deteriorated by light such as ultraviolet rays because R ^a1 does not contain a double bond.

The divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 3- Examples thereof include a methyl-1,5-pentylene group, a 2-ethyl-1,4-butylene group, and a 2-ethyl-3-methyl-1,4-butylene group. Among these, a straight chain saturated aliphatic hydrocarbon group is more preferable because a urethane bond formation reaction is likely to occur, and the polyurethane component (A) has an appropriate hardness, and thus a 1,6-hexylene group. Is more preferable.
The structural unit (a2-1) derived from diol is represented by the following general formula (a2-1).

式（ａ２−１）中、Ｒ^a21は、炭素原子数４〜１０の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン成分（Ａ）中に複数存在するＲ^a21は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−１）もＲ^a21が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−１）を含むことにより、熱、水によっても劣化しがたいポリウレタン成分となる。

In formula (a2-1), R ^a21 represents a divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms. Note that a plurality of R ^a21 present in the polyurethane component (A) may be the same or two or more types may be mixed. The structural unit (a2-1) is also unlikely to be deteriorated by light such as ultraviolet rays because R ^a21 does not contain a double bond. Further, by including the structural unit (a2-1), it becomes a polyurethane component that is hardly deteriorated by heat and water.

The divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 1,9-nonylene group, 1, Examples include 10-decylene group, 3-methyl-1,5-pentylene group, 2-ethyl-1,4-butylene group, and 2-ethyl-3-methyl-1,4-butylene group. Of these, a 3-methyl-1,5-pentylene group and a 1,6-hexylene group are more preferable because a urethane bond formation reaction is likely to occur. In the case of the structural unit (a2-1) derived from a diol, the urethane bond formation reaction is likely to occur regardless of whether the saturated aliphatic hydrocarbon group in the raw material compound is linear or branched. Will not change.
The structural unit (a2-2) derived from diol is represented by the following general formula (a2-2).

式（ａ２−２）中、Ｒ^a22は、炭素原子数３〜６の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン成分（Ａ）中に複数存在するＲ^a22は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−２）もＲ^a22が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−２）を含むことにより、柔軟性に優れたポリウレタン成分となる。

In formula (a2-2), R ^a22 represents a divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms. A plurality of R ^a22 present in the polyurethane component (A) may be the same or two or more types may be mixed. The structural unit (a2-2) is also unlikely to be deteriorated by light such as ultraviolet rays because R ^a22 does not contain a double bond. Moreover, it becomes a polyurethane component excellent in a softness | flexibility by including a structural unit (a2-2).

The divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 3-methyl-1,5-pentylene group, 2-ethyl-1 , 4-butylene group, 2-ethyl-3-methyl-1,4-butylene group. Of these, a straight chain saturated aliphatic hydrocarbon group is more preferable because a urethane bond formation reaction is likely to occur, and the polyurethane component (A) has an appropriate hardness, so that a 1,5-pentylene group is Further preferred.
The structural unit (a2-3) derived from diol is represented by the following general formula (a2-3).

式（ａ２−３）中、Ｒ^a23は、炭素原子数２〜６の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン成分（Ａ）中に複数存在するＲ^a23は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−３）もＲ^a23が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−３）を含むことにより、柔軟性に優れたポリウレタン成分となる。

In formula (a2-3), R ^a23 represents a divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms. A plurality of R ^a23 present in the polyurethane component (A) may all be the same or two or more may be mixed. Since the structural unit (a2-3) be R ^a23 is no double bond, hardly deteriorated by light such as ultraviolet light. Moreover, it becomes a polyurethane component excellent in a softness | flexibility by including a structural unit (a2-3).

  The divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,2-ethylene group, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 3-methyl-1,5-pentylene Group, 2-ethyl-1,4-butylene group, 2-ethyl-3-methyl-1,4-butylene group. Among these, a 1,4-butylene group is more preferable because a urethane bond formation reaction is likely to occur.

  The polyurethane component (A) is 10 to 25 mol%, preferably 15 to 18 mol, of the structural unit (a1) with respect to 100 mol% in total of the structural units (a1) and (a2-1) to (a2-3). %, The structural unit (a2-1) is 50 to 85 mol%, preferably 55 to 75 mol%, and the total of the structural units (a2-2) and (a2-3) is 3 to 35 mol%, preferably 8 In an amount of ˜28 mol%. When the structural unit (a1) is contained in the above amount, it becomes a polyurethane component that is not easily deteriorated by heat and is more difficult to discolor. When the structural unit (a2-1) is contained in the above amount, it becomes a polyurethane component that is more difficult to be deteriorated by heat and water, and the total of the structural units (a2-2) and (a2-3) is contained in the above amount. When it is, it becomes a polyurethane component excellent in flexibility. The total amount of the structural units (a2-2) and (a2-3) only needs to be in the above range, and the structural unit (a2-3) is not included in the polyurethane component (A). The amount of a2-2) may be in the range of 3 to 35 mol%, preferably 8 to 28 mol%, the polyurethane component (A) does not contain the structural unit (a2-2), and the structure The amount of the unit (a2-3) may be in the range of 3 to 35 mol%, preferably 8 to 28 mol%.

Here, the specific structures of the structural units (a1) and (a2-1) to (a2-3) and their contents are determined by pyrolysis GC / MS, ¹ H-NMR and ¹³ C for the polyurethane component (A). It can be determined by measuring NMR. A specific method will be described in Examples.

The hardness of the polyurethane component (A) measured according to JIS K-7311 is usually 83 to 92. In addition, the polyurethane component (A) has a tensile strength of usually 20 MPa or more measured as a dumbbell-shaped A5 type test piece in accordance with ISO527-2.
The polyurethane component (A) has a weight average molecular weight (Mw) measured by a gel permeation chromatography method (GPC method) and is usually from 2,000 to 1,050,000 in terms of standard polymethyl methacrylate, preferably 5,000. ˜500,000, more preferably in the range of 10,000 to 220,000. A specific method of GPC measurement will be described in Examples.

In addition, the polyurethane component (A) may be composed of one type of polyurethane or a mixture of two or more types of polyurethane.
Specifically, when the polyurethane component (A) is composed of one kind of polyurethane, an embodiment composed of the following polyurethane (A1) or an embodiment composed of the following polyurethane (A2) is suitable, and when it is a mixture, the following polyurethane An embodiment consisting of a mixture of (A1) and (A2) is preferred. When the polyurethane component (A) is composed of one of the following polyurethanes (A1), it is particularly preferable in terms of tensile strength, and when it is composed of one of the following polyurethanes (A2), it is particularly preferable in terms of flexibility and resilience. The polyurethanes (A1) and (A2) are particularly preferable because they are excellent in the balance of tensile strength, flexibility and restorability.

(Polyurethane (A1))
The polyurethane (A1) includes a structural unit (a1) represented by the following general formula (a1) derived from diisocyanate, a structural unit (a2-1) and a diol represented by the following general formula (a2-1) derived from diol. And a structural unit (a2-2) represented by the following general formula (a2-2). It is preferable that the structural unit (a2-3) represented by the above formula (a2-3) derived from diol is not included. In the polyurethane component (A1), the structural unit derived from diisocyanate is only the structural unit (a1), and the structural unit derived from diol is only the structural units (a2-1) and (a2-2). Particularly preferred.

式（ａ１）中、Ｒ^a1は、炭素原子数３〜８の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン（Ａ１）中に複数存在するＲ^a1は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ１）はＲ^a1が二重結合を含まないため、紫外線などの光によって劣化しがたい。

In the formula (a1), R ^a1 represents a divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms. A plurality of R ^a1 present in the polyurethane (A1) may be the same or two or more types may be mixed. The structural unit (a1) is unlikely to be deteriorated by light such as ultraviolet rays because R ^a1 does not contain a double bond.

  The divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 3- Examples thereof include a methyl-1,5-pentylene group, a 2-ethyl-1,4-butylene group, and a 2-ethyl-3-methyl-1,4-butylene group. Among these, a straight chain saturated aliphatic hydrocarbon group is more preferable because a urethane bond formation reaction easily occurs, and the polyurethane component (A1) has an appropriate hardness, so that a 1,6-hexylene group. Is more preferable.

式（ａ２−１）中、Ｒ^a21は、炭素原子数４〜１０の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン（Ａ１）中に複数存在するＲ^a21は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−１）もＲ^a21が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−１）を含むことにより、熱、水によっても劣化しがたいポリウレタン成分となる。

In formula (a2-1), R ^a21 represents a divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms. A plurality of R ^a21 present in the polyurethane (A1) may be the same or two or more types may be mixed. The structural unit (a2-1) is also unlikely to be deteriorated by light such as ultraviolet rays because R ^a21 does not contain a double bond. Further, by including the structural unit (a2-1), it becomes a polyurethane component that is hardly deteriorated by heat and water.

  The divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 1,9-nonylene group, 1, Examples include 10-decylene group, 3-methyl-1,5-pentylene group, 2-ethyl-1,4-butylene group, and 2-ethyl-3-methyl-1,4-butylene group. Of these, a 1,6-hexylene group is more preferable because a urethane bond formation reaction is likely to occur.

式（ａ２−２）中、Ｒ^a22は、炭素原子数３〜６の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン（Ａ１）中に複数存在するＲ^a22は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−２）もＲ^a22が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−２）を含むことにより、柔軟性に優れたポリウレタン成分となる。

In formula (a2-2), R ^a22 represents a divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms. A plurality of R ^a22 present in the polyurethane (A1) may be the same or two or more types may be mixed. The structural unit (a2-2) is also unlikely to be deteriorated by light such as ultraviolet rays because R ^a22 does not contain a double bond. Moreover, it becomes a polyurethane component excellent in a softness | flexibility by including a structural unit (a2-2).

  The divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 3-methyl-1,5-pentylene group, 2-ethyl-1 , 4-butylene group, 2-ethyl-3-methyl-1,4-butylene group. Of these, a straight chain saturated aliphatic hydrocarbon group is more preferable because a urethane bond formation reaction is likely to occur, and the polyurethane component (A1) has an appropriate hardness, so that a 1,5-pentylene group is Further preferred.

The polyurethane (A1) has a structural unit (a1) of 10 to 25 mol% and a structural unit (a2-1) based on a total of 100 mol% of the structural units (a1), (a2-1) and (a2-2). Are preferably contained in an amount of 50 to 85 mol% and the structural unit (a2-2) in an amount of 5 to 35 mol%. When the structural unit (a1) is contained in the above amount, it becomes a polyurethane component that is not easily deteriorated by heat and is more difficult to discolor. When the structural unit (a2-1) is contained in the above amount, it becomes a polyurethane component that is not easily deteriorated by heat and water, and when the structural unit (a2-2) is contained in the above amount, It becomes an excellent polyurethane component.
Here, the specific structure of the structural unit and the content thereof can be determined by the same method as described for the polyurethane component (A).

(Polyurethane (A2))
The polyurethane (A2) is composed of a structural unit (a1) represented by the following general formula (a1) derived from diisocyanate, a structural unit (a2-1) and a diol represented by the following general formula (a2-1) derived from diol. And a structural unit (a2-3) represented by the following general formula (a2-3). It is preferable that the structural unit (a2-2) represented by the formula (a2-2) derived from diol is not included. In the polyurethane component (A2), the structural unit derived from diisocyanate is only the structural unit (a1), and the structural units derived from diol are only the structural units (a2-1) and (a2-3). Particularly preferred.

式（ａ１）中、Ｒ^a1は、炭素原子数３〜８の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン（Ａ２）中に複数存在するＲ^a1は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ１）はＲ^a1が二重結合を含まないため、紫外線などの光によって劣化しがたい。

In the formula (a1), R ^a1 represents a divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms. A plurality of R ^a1 present in the polyurethane (A2) may be the same or two or more types may be mixed. The structural unit (a1) is unlikely to be deteriorated by light such as ultraviolet rays because R ^a1 does not contain a double bond.

  The divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 3- Examples thereof include a methyl-1,5-pentylene group, a 2-ethyl-1,4-butylene group, and a 2-ethyl-3-methyl-1,4-butylene group. Among these, a straight chain saturated aliphatic hydrocarbon group is more preferable because a urethane bond formation reaction easily occurs, and the polyurethane component (A2) has an appropriate hardness, and thus a 1,6-hexylene group. Is more preferable.

式（ａ２−１）中、Ｒ^a21は、炭素原子数４〜１０の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン（Ａ２）中に複数存在するＲ^a21は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−１）もＲ^a21が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−１）を含むことにより、熱、水によっても劣化しがたいポリウレタン成分となる。

In formula (a2-1), R ^a21 represents a divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms. Note that a plurality of R ^a21 present in the polyurethane (A2) may be the same or two or more types may be mixed. The structural unit (a2-1) is also unlikely to be deteriorated by light such as ultraviolet rays because R ^a21 does not contain a double bond. Further, by including the structural unit (a2-1), it becomes a polyurethane component that is hardly deteriorated by heat and water.

  The divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 1,9-nonylene group, 1, Examples include 10-decylene group, 3-methyl-1,5-pentylene group, 2-ethyl-1,4-butylene group, and 2-ethyl-3-methyl-1,4-butylene group. Of these, a 3-methyl-1,5-pentylene group is more preferable because a urethane bond formation reaction is likely to occur.

式（ａ２−３）中、Ｒ^a23は、炭素原子数２〜６の２価の飽和脂肪族炭化水素基を表す。なお、ポリウレタン（Ａ２）中に複数存在するＲ^a23は、全て同じであっても２種類以上が混在していてもよい。構造単位（ａ２−３）もＲ^a23が二重結合を含まないため、紫外線などの光によって劣化しがたい。また、構造単位（ａ２−３）を含むことにより、柔軟性に優れたポリウレタン成分となる。

In formula (a2-3), R ^a23 represents a divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms. A plurality of R ^a23 present in the polyurethane (A2) may be the same or two or more types may be mixed. Since the structural unit (a2-3) be R ^a23 is no double bond, hardly deteriorated by light such as ultraviolet light. Moreover, it becomes a polyurethane component excellent in a softness | flexibility by including a structural unit (a2-3).

  The divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms may be a linear or branched saturated aliphatic hydrocarbon group. Specifically, 1,2-ethylene group, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 3-methyl-1,5-pentylene Group, 2-ethyl-1,4-butylene group, 2-ethyl-3-methyl-1,4-butylene group. Among these, a 1,4-butylene group is more preferable because a urethane bond formation reaction is likely to occur.

  The polyurethane (A2) has a structural unit (a1) of 10 to 25 mol% and a structural unit (a2-1) based on a total of 100 mol% of the structural units (a1), (a2-1) and (a2-3). Is preferably contained in an amount of 50 to 85 mol%, and the structural unit (a2-3) in an amount of 3 to 25 mol%. When the structural unit (a1) is contained in the above amount, it becomes a polyurethane component that is not easily deteriorated by heat and is more difficult to discolor. When the structural unit (a2-1) is contained in the above amount, it becomes a polyurethane component that is not easily deteriorated by heat and water, and when the structural unit (a2-3) is contained in the above amount, It becomes an excellent polyurethane component.

Here, the specific structure of the structural unit and the content thereof can be determined by the same method as described for the polyurethane component (A).
When the polyurethane component (A) is composed of a mixture of the polyurethanes (A1) and (A2), the total amount of the polyurethanes (A1) and (A2) is 100 parts by mass, and the polyurethane (A1) is 10 to 90 parts by mass. The polyurethane (A2) is preferably mixed in an amount of 10 to 90 parts by mass.

  In an embodiment in which the polyurethane component (A) is made of one type of polyurethane, for example, an embodiment made of the polyurethane (A1) or an embodiment made of the polyurethane (A2), the polyurethane component (A) usually conforms to JIS K-7311 of the one type of polyurethane. Measured in accordance with ISO527-2, tensile strength measured as a dumbbell-shaped A5 test piece, and Mw and Mw / Mn measured by the GPC method are within the range described for the polyurethane component (A). is there. In the embodiment in which the polyurethane component (A) is made of a mixture of polyurethanes, for example, in the embodiment made of a mixture of the polyurethanes (A1) and (A2), the hardness measured in accordance with JIS K-7311 of the mixture is usually The tensile strength measured as a dumbbell-shaped A5 type test piece according to ISO 527-2 and Mw and Mw / Mn measured by the GPC method are in the range described for the polyurethane component (A). In the embodiment where the polyurethane component (A) is composed of a mixture of polyurethanes, the amount of the structural unit (a1), the amount of the structural unit (a2-1) and the structural units (a2-2) and (a2- The total amount of 3) is in the range described for the polyurethane component (A).

  The method for preparing the polyurethane component (A) is not particularly limited as long as the polyurethane component (A) having the above-described characteristics is obtained. That is, in an embodiment in which the polyurethane component (A) is made of one type of polyurethane, for example, an embodiment of the polyurethane (A1) or an embodiment of the polyurethane (A2), if the polyurethane is polymerized by a usual method, the polyurethane component ( A) can be prepared. In the embodiment in which the polyurethane component (A) is made of a mixture of polyurethanes, for example, in the embodiment made of a mixture of the above polyurethanes (A1) and (A2), the respective polyurethanes are polymerized by a usual method, and then these are treated by a usual method. If mixed, the polyurethane component (A) can be prepared.

  Specifically, the polyurethane that constitutes the polyurethane component (A) is a diisocyanate and a diol using a chain extender, if necessary, under reaction conditions such as raw materials, ratios, temperatures, and time. Obtained by reaction. For example, the diisocyanate is preferably used in an amount of 0.95 to 1.10 mol with respect to a total of 1 mol of diol, and the chain extender is 0 to 0.01 with respect to 100 parts by mass of the total of diisocyanate and diol. It is preferably used in an amount of parts by mass. Polyurethane is usually obtained as pellets. In the polyurethane component (A), diisocyanate forms a structural unit (a1) derived from diisocyanate, and diol forms structural units (a2-1) to (a2-3) derived from diol.

  As the diisocyanate that is a raw material for forming the structural unit (a1), for example, hexamethylene diisocyanate is preferably used. Further, as a diol which is a raw material for forming the structural unit (a2-1), polyhexamethylene carbonate diol and poly (3-methyl-1,5-pentylene carbonate) diol are structural units (a2-2). Polycaprolactone diol is suitably used as the diol that is the raw material for forming the structural unit, and polytetramethylene glycol is suitably used as the diol that is the raw material for forming the structural unit (a2-3).

  Examples of the chain extender include short chain diol, short chain diamine, short chain triol, and polyvalent amine. Specific examples of the short-chain diol include 1,3-butanediol, 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,6-hexanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3 -Propanediol, 2-methyl-1,5-pentanediol. Specific examples of the short-chain diamine include ethylene diamine, tetraethylene diamine, diphenyldiaminomethane, paraphenylene diamine, hexamethylene diamine, and isophorone diamine. Specific examples of the short chain triol include glycerin, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, diglycerin, trimethylolethane, and triethanolamine. Specific examples of the polyvalent amine include triethylenetetramine, tetraethylenepentamine, and pentamethylenehexamine. A chain extender may be used individually or may be used in combination of 2 or more type.

Since the chain extender is used in a normal amount, for example, 0.1 parts by mass or less with respect to 100 parts by mass in total of diisocyanate and diol, the structural units (a1) and (a2−) in the polypropylene component (A) are used. In the analysis for determining the specific structure and content of 1) to (a2-3), the structural unit derived from the chain extender is not detected, and the above-described specific structure and content thereof are determined. Is considered to have no effect.
Thus, the polyurethane component (A) which has the characteristics mentioned above can be manufactured by adjusting reaction conditions, such as the raw material to be used, the ratio, temperature, and time, suitably.

[Additive (B)]
The additive (B) used in the present invention comprises an ultraviolet absorber (B1), a hindered phenol antioxidant (B2), a neutral phosphate ester (B3-1), and a neutral phosphite ester (B3-2). At least one phosphorous stabilizer (B3), hindered amine stabilizer (B4) and carbodiimide rebinding agent (B5).

(Ultraviolet absorber (B1))
By using the ultraviolet absorber (B1), it becomes a polyurethane composition for a watch that is hardly deteriorated by ultraviolet rays.

  Examples of the ultraviolet absorber (B1) include benzotriazole-based, benzophenone-based, salicylic acid derivative-based, and cyanoacrylate-based ultraviolet absorbers. The ultraviolet absorber (B1) may be used alone or in combination of two or more.

  Specific examples of the benzotriazole ultraviolet absorber include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2′-hydroxy-5). '-Methylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'- Methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-4) '-N-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-amylphenyl) ) Zotriazol, 2- [2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol].

More specifically, Tinuvin P / FL, Tinuvin 234, Tinuvin 326 / FL, Tinuvin 329 / FL (trade name, manufactured by Ciba Specialty Chemicals) can be used.
Specific examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, and 2,2′-dihydroxy-4,4. '-Dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone Trihydrate, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-Hydroxy-4- (2-hydride Carboxymethyl-3-methacryloxy) propoxy benzophenone and bis (2-methoxy-4-hydroxy-5-benzoylphenyl) include methane.

Specific examples of salicylic acid derivative ultraviolet absorbers include phenyl salicylate, salicylic acid-P-octylphenyl, and salicylic acid-pt-butylphenyl.
Specific examples of the cyanoacrylate ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3′-diphenyl acrylate and ethyl-2-cyano-3,3′-diphenyl acrylate.
Of these, benzophenone-based ultraviolet absorbers are preferable because deterioration of the polyurethane component (A) due to ultraviolet rays can be further suppressed.

(Hindered phenolic antioxidant (B2))
Since the hindered phenol-based antioxidant (B2) can trap radicals generated when the polyurethane component (A) is decomposed, it is difficult to deteriorate by using the hindered phenol-based antioxidant (B2). A polyurethane composition for a watch is obtained.

  Examples of the hindered phenol antioxidant (B2) include monocyclic hindered phenols, bicyclic hindered phenols, and polycyclic (tricyclic or higher) hindered phenols. The hindered phenolic antioxidant (B2) may be used alone or in combination of two or more.

  Specific examples of the monocyclic hindered phenols include 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4-methoxyphenol, 2,6-di-tert-butyl- 2,4-methylphenol, 2,6-di-tert-butylphenol, 2-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-ethylphenol, n-octadecyl-3- ( 4'-hydroxy-3,5-di-tert-butylphenyl) propionate, dioctadecyl-4-hydroxy-3,5-di-tert-butylbenzylphosphonate, and 6- (4-oxy-3,5-di- -Tert-butylanilino) -2,4-bis- (n-octylthio) -1,3,5-triazine.

  Specific examples of the bicyclic hindered phenols include 4,4′-thiobis (6-tert-3-methylphenol), 4,4′-butylidenebis (6-tert-butylphenol), 4,4′- Methylenebis (6-tert-butylphenol), 4,4'-bis (2,6-di-tert-butylphenol), 4,4'-thiobis (6-tert-butyl-o-cresol), 4,4'- Methylene bis (6-tert-butyl-o-cresol), 2,2'-methylene bis (4-methyl-6-tert-butylphenol), 2,2'-thiobis (6-tert-butyl-4-methylphenol) and 1,6-bis (3,5-di-tert-butyl-4-hydroxy-2-methylphenyl) butane.

Polycyclic (tricyclic or higher) hindered phenols include 1,1,3-tris (3,5-di-tert-butyl-4-hydroxybenzyl) methylene, 1,3,5-tris (3,5 -Di-tert-butyl-4-hydroxybenzyl) isocyanurate, tetrakis [β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane.
More specifically, Irganox 1010, Irganox 1035, and Irganox 1520 (trade names, manufactured by Ciba Geigy Corporation) can be used.

(Phosphorus stabilizer (B3))
Since the phosphorus stabilizer (B3) can trap radicals generated when the polyurethane component (A) is decomposed, it is difficult to deteriorate by using the phosphorus stabilizer (B3). It becomes a thing.

  The phosphorus stabilizer (B3) is at least one selected from a neutral phosphate ester (B3-1) and a neutral phosphite ester (B3-2). The phosphorus stabilizer (B3) may be used alone or in combination of two or more. That is, the neutral phosphate ester (B3-1) may be used alone or in combination of two or more, or the neutral phosphite ester (B3-2) may be used alone. One or more neutral phosphates (B3-1) may be used in combination with one or more neutral phosphites (B3-2). May be.

  Specific examples of the neutral phosphate ester (B3-1) include tricresyl phosphate, trixylenyl phosphate, trioctyl phosphate, trimethylolpropane phosphate, triphenyl phosphate, tris (nonylphenyl) Phosphate, triethyl phosphate, tris (tridecyl) phosphate, tetraphenyldipropylene glycol diphosphate, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphate, tetra (tridecyl) -4,4'-isopropylidenediphenyl phosphate Bis (tridecyl) pentaerythritol diphosphate, bis (nonylphenyl) pentaerythritol diphosphate, tristearyl phosphate, distearyl Examples thereof include intererythritol diphosphate, tris (2,4-di-t-butylphenyl) phosphate, and hydrogenated bisphenol A / pentaerythritol phosphate polymer.

  As the neutral phosphate ester (B3-1), the above compound may be used, but a neutral phosphate ester represented by the following formula (b3-1) is particularly preferably used. Such a compound is superior in its ability to trap radicals generated when the polyurethane component (A) is decomposed.

式（ｂ３−１）中、Ｒ^b311〜Ｒ^b314は、それぞれ独立に、炭素原子数１０〜１６の脂肪族炭化水素基を表す。

In formula (b3-1), R ^{b311 to} R ^b314 each independently represent an aliphatic hydrocarbon group having 10 to 16 carbon atoms.

  The aliphatic hydrocarbon group having 10 to 16 carbon atoms may be a linear, branched, or cyclic aliphatic hydrocarbon group, or a saturated or unsaturated aliphatic hydrocarbon group. Specific examples of the aliphatic hydrocarbon group having 10 to 16 carbon atoms include linear alkyl groups such as a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group (cetyl group). Groups are preferably used.

R ^{b315 to} R ^b318 each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms.
Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, isopropyl group, sec- Examples include a butyl group, an isobutyl group, a t-butyl group, an isopentyl group, a t-pentyl group, a neopentyl group, and an isohexyl group.

Neutral phosphoric acid esters of the formula (b3-1), since it has a specific substituent in R ^B315 to R ^B318, compound is hardly crystallized, advantages distributed uniformly across during watch polyurethane composition There is.

In particular, R ^b315 and R ^b317 are linear alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, and R ^b316 and R ^b318 are components having 3 to 6 carbon atoms, preferably 3 to 4 carbon atoms. A branched alkyl group is more preferable from the viewpoint of the advantages described above.

R ^b3191 and R ^b3192 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.
Examples of the linear or branched alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, isopropyl group, sec-butyl group, and isobutyl group. , T-butyl group, isopentyl group, t-pentyl group, and neopentyl group.

However, the total number of carbon atoms of R ^b3191 and R ^b3192 is 1 to 5. Thus, for example, when R ^b3191 is a hydrogen atom, R ^b3192 is a linear or branched alkyl group having 1 to 5 carbon atoms, and when R ^b3191 is a methyl group, R ^b3192 is 1 carbon atom. When R ^b3191 is an ethyl group, R ^b3192 is a linear or branched alkyl group having 2 to 3 carbon atoms.

In particular, since the compound is difficult to crystallize and spreads uniformly in the timepiece polyurethane composition, R ^b3191 is a hydrogen atom, and R ^b3192 is a linear or branched alkyl group having 1 to 5 carbon atoms. It is more preferable that

  Specific examples of the neutral phosphite (B3-2) include trioleyl phosphite, trioctyl phosphite, trimethylolpropane phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, and triethyl phosphite. , Tris (tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,4'-isopropylidenediphenyl phosphite, bis (tridecyl) penta Erythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite And tris (2,4-di-t-butylphenyl) phosphite and hydrogenated bisphenol A-pentaerythritol phosphite polymer.

  As the neutral phosphite (B3-2), the above-mentioned compounds may be used, but the neutral phosphite represented by the following formula (b3-2) is particularly preferably used. Such a compound is superior in its ability to trap radicals generated when the polyurethane component (A) is decomposed.

式（ｂ３−２）中、Ｒ^b321〜Ｒ^b324は、それぞれ独立に、炭素原子数１０〜１６の脂肪族炭化水素基を表す。

In formula (b3-2), R ^{b321 to} R ^b324 each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms.

  The aliphatic hydrocarbon group having 10 to 16 carbon atoms may be a linear, branched, or cyclic aliphatic hydrocarbon group, or a saturated or unsaturated aliphatic hydrocarbon group. Specific examples of the aliphatic hydrocarbon group having 10 to 16 carbon atoms include linear alkyl groups such as a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group (cetyl group). Groups are preferably used.

R ^{b325 to} R ^b328 each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms.
Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, isopropyl group, sec- Examples include a butyl group, an isobutyl group, a t-butyl group, an isopentyl group, a t-pentyl group, a neopentyl group, and an isohexyl group.

Neutral phosphite represented by the formula (b3-2), since it has a specific substituent in R ^{B 325} to R ^{B 328,} compound is hardly crystallized, distributed uniformly across during watch polyurethane composition There are advantages.

In particular, R ^b325 and R ^b327 are linear alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, and R ^b326 and R ^b328 are components having 3 to 6 carbon atoms, preferably 3 to 4 carbon atoms. A branched alkyl group is more preferable from the viewpoint of the advantages described above.

R ^b3291 and R ^b3292 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.
Examples of the linear or branched alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, isopropyl group, sec-butyl group, and isobutyl group. , T-butyl group, isopentyl group, t-pentyl group, and neopentyl group.

However, the total number of carbon atoms of R ^b3291 and R ^b3292 is 1 to 5. Thus, for example, when R ^b3291 is a hydrogen atom, R ^b3292 is a linear or branched alkyl group having 1 to 5 carbon atoms, and when R ^b3291 is a methyl group, R ^b3292 is 1 carbon atom. When R ^b3291 is an ethyl group, R ^b3292 is a linear or branched alkyl group having 2 to 3 carbon atoms.

In particular, since the compound is difficult to crystallize and spreads uniformly in the timepiece polyurethane composition, R ^b3291 is a hydrogen atom and R ^b3292 is a linear or branched alkyl group having 1 to 5 carbon atoms. It is more preferable that

(Hindered amine stabilizer (B4))
Since the hindered amine stabilizer (B4) can trap radicals generated when the polyurethane component (A) is decomposed, the use of the hindered amine stabilizer (B4) makes it difficult to deteriorate the timepiece polyurethane composition. It becomes a thing. The hindered amine stabilizer (B4) may be used alone or in combination of two or more.

  As the hindered amine stabilizer (B4), specifically, 4-benzoyloxy-2,2 ', 6,6'-tetramethylpiperidine N- (2-ethylphenol) -N'-(2-ethoxy- 5-tert-butylphenol) oxalic acid diamine, N- (2-ethyl-phenol) -N- (2-ethoxy-5-tert-butylphenol) oxalic acid diamine, bis (2,2 ', 6,6' -Tetramethyl-4-piperidine) sebacate.

  As the hindered amine stabilizer (B4), the above compounds may be used, but a hindered amine stabilizer represented by the following formula (b4) is particularly preferably used. Such a compound is superior in its ability to trap radicals generated when the polyurethane component (A) is decomposed.

式（ｂ４）中、Ｒ^b41およびＲ^b42は、それぞれ独立に、炭素原子数１〜１０の脂肪族炭化水素基を表す。

In formula (b4), R ^b41 and R ^b42 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms.

The aliphatic hydrocarbon group having 1 to 10 carbon atoms may be a linear, branched or cyclic aliphatic hydrocarbon group, or a saturated or unsaturated aliphatic hydrocarbon group.
Specific examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, heptyl group, and octyl group. , Nonyl group, decyl group, isopropyl group, sec-butyl group, isobutyl group, t-butyl group, isopentyl group, t-pentyl group, neopentyl group, isohexyl group, 2-ethylhexyl group, etc. An alkyl group is preferably used. Of these, linear or branched alkyl groups having 5 to 10 carbon atoms are more preferable because the solubility of the compound in the timepiece polyurethane composition is increased and the entire composition becomes stable.

R ^b43 represents a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.
Examples of the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms include methylene group, 1,2-ethylene group, 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1 2,6-hexylene group, 1,7-heptylene group, 1,8-octylene group, 1,9-nonylene group, 1,10-decylene group, 3-methyl-1,5-pentylene group, etc. A chain or branched alkylene group is preferably used. Among these, a divalent linear or branched alkylene group having 5 to 10 carbon atoms is more preferable because the solubility of the compound in the polyurethane composition for a watch is increased and the entire composition is stabilized. .

In particular, since the solubility of the compound in the polyurethane composition for watches is increased and the whole composition is stabilized, the sum of the carbon atoms of R ^b41 , R ^b42 and R ^b43 is 16 to 30 in the above. Is more preferable. If the sum of the carbon atoms is too small, the compound may bleed on the surface of the polyurethane composition for a watch. If the sum of the carbon atoms is too large, the solubility of the compound in the watch polyurethane composition may be reduced. May fall.

(Carbodiimide rebinding agent (B5))
The carbodiimide-based rebinding agent (B5) is a compound having a —N═C═N— group, and can recombine the hydrolyzed polyurethane. Therefore, by using the carbodiimide-based rebinding agent (B5). It becomes a polyurethane composition for a watch that is difficult to deteriorate.

  Examples of the carbodiimide rebinding agent (B5) include a monocarbodiimide compound and a polycarbodiimide compound. The carbodiimide-based rebinding agent (B5) may be used alone or in combination of two or more.

Specific examples of the monocarbodiimide compound include N, N′-di-2,6-diisopropylphenylcarbodiimide.
Specific examples of the polycarbodiimide compound include poly (4,4′-diphenylmethanecarbodiimide), poly (4,4′-dicyclohexylmethanecarbodiimide), poly (1,3,5-triisopropylbenzene) polycarbodiimide, poly ( 1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene) polycarbodiimide.

  In the timepiece polyurethane composition according to the present invention, deterioration such as discoloration in the initial stage can be suppressed by including the ultraviolet absorber (B1) and the hindered phenol antioxidant (B2). In addition, by containing a phosphorus stabilizer (B3), a hindered amine stabilizer (B4) and a carbodiimide rebinding agent (B5), it is possible to suppress deterioration due to heat, water, etc. over a long period of time and decrease in tensile strength. It is done. Further, the hindered phenol antioxidant (B2) and the phosphorus stabilizer (B3) (in particular, the neutral phosphate ester represented by the formula (3b-1) and / or the formula (3b-2) When used in combination with (phosphorous phosphite ester), it is considered that the ability of the phosphorus stabilizer (B3) to trap radicals is further enhanced. Thus, a polyurethane composition for a watch having excellent durability can be obtained by combining the above-described polyurethane component (A) and five specific additives.

[Other additives (B ')]
In the polyurethane composition for timepieces according to the present invention, other additives (B ′) may be used as necessary within the range not impairing the effects of the present invention. Other additives (B ′) may be used alone or in combination of two or more.

Examples of other additives (B ′) include pigments, dyes, silicon dioxide, and softeners.
Specific examples of pigments and dyes include inorganic pigments such as carbon black and titanium oxide with good weather resistance, organic pigments and dyes such as phthalocyanine blue, phthalocyanine green, quinacridone red, indanthrene orange, and isoindolinone yellow Is mentioned.

Silicon dioxide can be added mainly for adjusting the hardness of the polyurethane composition for watches. Specifically, silicon dioxide having a particle size of 50 μm or less such as fumed silica or glass beads is preferably used.
The softening agent can be added mainly for adjusting the hardness of the timepiece polyurethane composition. Specifically, polyurethane other than the polyurethane component (A); nitrile rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber and Rubbers such as natural rubber; oils and the like.

[Polyurethane composition for watches]
In the polyurethane composition for timepieces according to the present invention, an ultraviolet absorber (B1), a hindered phenol antioxidant (B2), a phosphorus stabilizer (B3), a hindered amine stabilizer (B4), and a carbodiimide The rebinding agent (B5) is preferably contained in an amount of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the polyurethane component (A). In addition, the ultraviolet absorber (B1), the hindered phenol-based antioxidant (B2), the phosphorus-based stabilizer (B3), and the hindered amine-based stabilizer (B4) are contained in 100 parts by mass of the polyurethane component (A). , Each contained in an amount of 0.01 to 0.1 parts by mass, and the carbodiimide rebinding agent (B5) is 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the polyurethane component (A). More preferably, it is contained in an amount of. When the additive is contained in the above amount, deterioration of the polyurethane composition for a watch can be further suppressed.

  In addition, what is necessary is just to use another additive (B ') in the quantity of the range which does not impair the effect of this invention, For example, an additive (B') is 0 with respect to 100 mass parts of polyurethane components (A). It is used in an amount exceeding 10 parts by mass and exceeding 10 parts by mass. For example, when a softener is used as the additive (B ′) in order to obtain a composition having low hardness, the softener exceeds 0 part by weight and is 20 parts by weight with respect to 100 parts by weight of the polyurethane component (A). It can also be used in an amount of less than parts.

  The polyurethane composition for timepieces according to the present invention has a hardness measured according to JIS K-7311 of usually 83 to 92. Moreover, the polyurethane composition for timepieces according to the present invention may have a hardness of 60 or more and less than 83. A composition having low hardness can be prepared, for example, by blending a softener as the other additive (B ′). In addition, the timepiece polyurethane composition according to the present invention has a tensile strength of usually 20 MPa or more, measured as a dumbbell-shaped A5-type test piece in accordance with ISO527-2.

  Furthermore, the polyurethane composition for watches according to the present invention has a tensile strength reduction rate in the range of usually 0 to 3% in the water resistance test (20 days in 95 ° C. water) described in the examples. Moreover, in the heat resistance test (1000 degreeC water 1000 hours) demonstrated in an Example, the fall rate of tensile strength exists in the range of 0 to 3% normally.

The timepiece polyurethane composition according to the present invention is obtained by appropriately mixing the polyurethane component (A), the additive (B), and other additives (B ′) as necessary.
In addition, in the obtained polyurethane composition for timepieces, the polyurethane component (A) and the additive (B) are present unchanged from the state before mixing. Moreover, in the obtained polyurethane composition for timepieces, the contents of the structural units (a1) and (a2-1) to (a2-3) of the polyurethane component (A) are also contained in the polyurethane component (A). It is the same as the amount.

<Watch bands and watches>
The watch band according to the present invention is obtained from the above-described polyurethane composition for a watch, and the watch (specifically, a wrist watch) according to the present invention includes the watch band.

  Since the timepiece band or timepiece according to the present invention uses the polyurethane composition, it is difficult to deteriorate and can be used for a long time. Specifically, such a watch band or watch can be used for a long period of time even when used in sports such as swimming, which is in direct contact with sweat from the skin and exposed to water or sunlight. Further, the watch band or the watch according to the present invention is excellent from the viewpoint of the environment because the waste generated during the injection molding of the polyurethane composition can be reused for the manufacture of the watch band.

  The watch band according to the present invention is produced by injection molding of the above-mentioned watch polyurethane composition containing the polyurethane component (A) and the additive (B) which are usually pelletized. The timepiece according to the present invention is manufactured using the timepiece band by a normal method.

  In the obtained watch band, the polyurethane component (A) and the additive (B) are present in the same manner as in the watch polyurethane composition, and the content thereof is also in the watch polyurethane composition. It is the same as the content in In the obtained watch band, the contents of the structural units (a1) and (a2-1) to (a2-3) of the polyurethane component (A) are also the same as the contents in the polyurethane composition for watches. It is.

As described above, the present invention relates to the following.
[1] Structural unit (a1) represented by the following general formula (a1) derived from diisocyanate, Structural unit (a2-1) represented by the following general formula (a2-1) derived from diol, and derived from diol At least one selected from the structural unit (a2-2) represented by the following general formula (a2-2) and the structural unit (a2-3) represented by the following general formula (a2-3) derived from diol Containing polyurethane component (A);
At least one phosphorus-based stabilization selected from an ultraviolet absorber (B1), a hindered phenol-based antioxidant (B2), a neutral phosphate ester (B3-1), and a neutral phosphite ester (B3-2) An additive (B) consisting of an agent (B3), a hindered amine stabilizer (B4) and a carbodiimide rebinding agent (B5),
The polyurethane component (A) is 10 to 25 mol% of the structural unit (a1) and the structural unit (a2-1) with respect to the total of 100 mol% of the structural units (a1) and (a2-1) to (a2-3). ), And a total of the structural units (a2-2) and (a2-3) in an amount of 3 to 35 mol%.

（式（ａ１）中、Ｒ^a1は、炭素原子数３〜８の２価の飽和脂肪族炭化水素基を表す。）

(In the formula (a1), R ^a1 represents a divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms.)

（式（ａ２−１）中、Ｒ^a21は、炭素原子数４〜１０の２価の飽和脂肪族炭化水素基を表す。）

(In formula (a2-1), R ^a21 represents a divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms.)

（式（ａ２−２）中、Ｒ^a22は、炭素原子数３〜６の２価の飽和脂肪族炭化水素基を表す。）

(In formula (a2-2), R ^a22 represents a divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms.)

（式（ａ２−３）中、Ｒ^a23は、炭素原子数２〜６の２価の飽和脂肪族炭化水素基を表す。）

(In formula (a2-3), R ^a23 represents a divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms.)

  According to the polyurethane composition, it is possible to manufacture a watch band that is not easily deteriorated and can be used for a long time. In addition, the polyurethane composition is excellent in terms of environment because waste generated during injection molding can be reused in the manufacture of watch bands.

  [2] The neutral phosphate ester (B3-1) is represented by the following formula (b3-1), and the neutral phosphite ester (B3-2) is represented by the following formula (b3-2). The timepiece polyurethane composition according to [1] above, wherein

（式（ｂ３−１）中、Ｒ^b311〜Ｒ^b314は、それぞれ独立に、炭素原子数１０〜１６の脂肪族炭化水素基を表し、Ｒ^b315〜Ｒ^b318は、それぞれ独立に、炭素原子数１〜６の直鎖もしくは分枝状のアルキル基を表し、Ｒ^b3191およびＲ^b3192は、それぞれ独立に、水素原子または炭素原子数１〜５の直鎖もしくは分枝状のアルキル基を表し、Ｒ^b3191およびＲ^b3192の炭素原子数の合計は、１〜５である。）

(In formula (b3-1), R ^{b311 to} R ^b314 each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, and R ^{b315 to} R ^b318 each independently represents 1 carbon atom. ^Represents a linear or branched alkyl group of ^˜6 , R ^b3191 and R ^b3192 each independently represents a hydrogen atom or a linear or branched alkyl group of 1 to 5 carbon atoms, and R ^{b3191 And} the total number of carbon atoms of R ^b3192 is 1 to 5.)

（式（ｂ３−２）中、Ｒ^b321〜Ｒ^b324は、それぞれ独立に、炭素原子数１０〜１６の脂肪族炭化水素基を表し、Ｒ^b325〜Ｒ^b328は、それぞれ独立に、炭素原子数１〜６の直鎖もしくは分枝状のアルキル基を表し、Ｒ^b3291およびＲ^b3292は、それぞれ独立に、水素原子または炭素原子数１〜５の直鎖もしくは分枝状のアルキル基を表し、Ｒ^b3291およびＲ^b3292の炭素原子数の合計は、１〜５である。）
［３］ ヒンダードアミン系安定化剤（Ｂ４）が、下記式（ｂ４）で表わされることを特徴とする上記［１］または［２］に記載の時計用ポリウレタン組成物。

(In formula (b3-2), R ^{b321 to} R ^b324 each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, and R ^{b325 to} R ^b328 each independently represents 1 carbon atom. ^Represents a linear or branched alkyl group of ^˜6 , R ^b3291 and R ^b3292 each independently represent a hydrogen atom or a linear or branched alkyl group of 1 to 5 carbon atoms, and R ^{b3291 And} the total number of carbon atoms of R ^b3292 is 1 to 5.)
[3] The polyurethane composition for timepieces according to the above [1] or [2], wherein the hindered amine stabilizer (B4) is represented by the following formula (b4).

（式（ｂ４）中、Ｒ^b41およびＲ^b42は、それぞれ独立に、炭素原子数１〜１０の脂肪族炭化水素基を表し、Ｒ^b43は、炭素原子数１〜１０の２価の脂肪族炭化水素基を表す。）

(In formula (b4), R ^b41 and R ^b42 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and R ^b43 represents a divalent aliphatic carbon atom having 1 to 10 carbon atoms. Represents a hydrogen group.)

  The phosphorus stabilizer (B3) or hindered amine stabilizer (B4) having a specific structure as represented by the above formula has the ability to trap radicals generated when the polyurethane component (A) is decomposed. Since it is excellent, when these stabilizers are used, decomposition of the polyurethane component (A) can be further suppressed.

[4] The timepiece polyurethane composition according to any one of the above [1] to [3], wherein the ultraviolet absorber (B1) is a benzotriazole-based ultraviolet absorber.
When a benzotriazole ultraviolet absorber is used, deterioration of the polyurethane component (A) due to ultraviolet rays can be further suppressed.

[5] An ultraviolet absorber (B1), a hindered phenol antioxidant (B2), a phosphorus stabilizer (B3), a hindered amine stabilizer (B4), and a carbodiimide rebinding agent (B5) are polyurethane. The polyurethane for a watch according to any one of the above [1] to [4], which is contained in an amount of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A). Composition.
When the additive is contained in the above amount, deterioration of the polyurethane composition for a watch can be further suppressed.

  [6] A timepiece band obtained from the polyurethane composition for timepieces according to any one of [1] to [5] above.

[7] A timepiece including the timepiece band according to [6] above.
When the polyurethane composition is used, a watch band or a watch that is not easily deteriorated and can be used for a long time is obtained. Moreover, since the waste generated at the time of injection molding can be reused for the production of a watch band, the above-mentioned polyurethane composition can provide a watch band or a watch that is excellent in terms of environment.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

<Measurement method>
(Confirmation of structural units (a1) and (a2-1) to (a2-3) and their contents)
The structural unit was confirmed by measuring pyrolysis GC / MS under the following measurement conditions (1) and (2) and confirming from the obtained fragment.
・ Measurement conditions (1)
Thermal decomposition temperature: 500 ° C
GC column: 0.25 mm inner diameter x 30 m
Stainless capillary column
Stationary phase 5% phenylpolydimethylsiloxane Temperature rising condition: The temperature was raised from 50 ° C. to 320 ° C. at 8 ° C./min.
Flow rate: 1.5mL / min
MS condition: mass range m / z 10-800
Scanning speed 1 second / scan ・ Measurement condition (2)
Thermal decomposition temperature: 400 ° C
GC column: 0.25 mm inner diameter x 30 m
Stainless capillary column
Stationary phase 5% phenylpolydimethylsiloxane Temperature rising condition: The temperature was raised from 50 ° C. (3 minutes hold) to 320 ° C. at 8 ° C./min.
Flow rate: 1.5mL / min
MS condition: mass number range m / z 20-800
Scan rate 1 second / scan Reaction reagent: Tetramethylammonium hydroxide The content of the structural unit was determined by measuring ¹ H-NMR and ¹³ C-NMR and determining from the peak area ratio of the spectrum. ^{In 1} H-NMR and ¹³ C-NMR measurements, heavy HFIP was used as a solvent.
(hardness)
The sample was measured according to JIS K-7311.
(Tensile strength)
The sample was made into a dumbbell-shaped A5 type test piece by injection molding and measured according to ISO 527-2.

<Evaluation method>
(Water resistance test)
A polyurethane composition for a watch was injection molded to obtain a dumbbell-shaped A5 test piece. Moreover, only the polyurethane (A1) (Preparation Example 1 described later) was injection molded to obtain a dumbbell-shaped A5 type test piece. The obtained test piece was immersed in water at 95 ° C. About the test piece after 5 days, 10 days, 15 days, and 20 days after being immersed in water, the difference with the test piece before being immersed in water was evaluated. Specifically, the evaluation was made from the change in the maximum value of tensile strength (decrease rate (%)) and the change in color by visual observation. In addition, the tensile strength was measured based on ISO527-2 as mentioned above. Moreover, the test piece obtained from any composition and the test piece obtained only from the polyurethane (A1) were white before the water resistance test (before being immersed in water).

(Heat resistance test)
A polyurethane composition for a watch was injection molded to obtain a dumbbell-shaped A5 test piece. Moreover, only the polyurethane (A1) (Preparation Example 1 described later) was injection molded to obtain a dumbbell-shaped A5 type test piece. The obtained test piece was placed in an 80 ° C. furnace. About the test piece after 500 hours and 1000 hours after putting into a furnace, the difference with the test piece before putting into a furnace was evaluated. Specifically, the evaluation was made from the change in the maximum value of tensile strength (decrease rate (%)) and the change in color by visual observation. In addition, the tensile strength was measured based on ISO527-2 as mentioned above. Moreover, the test piece obtained from any composition and the test piece obtained from polyurethane (A1) were white before the heat resistance test (before being put into the furnace).

(Light resistance test)
A watch band was produced by injection molding the polyurethane composition for a watch. Moreover, only polyurethane (A1) (Preparation Example 1 described later) was injection molded to produce a watch band. The produced watch band was set on a sunshine weather meter. For the watch bands 24 hours, 48 hours and 72 hours after setting, the difference between the watch bands before setting on the sunshine weather meter was evaluated. Specifically, the color change was visually evaluated. The watch band obtained from any of the compositions and the watch band obtained from the polyurethane (A1) were white before the light resistance test (before being set in the sunshine weather meter).

(Watch band wearing test)
A polyurethane composition for a watch was injection molded into a watch band, and a watch was produced from the watch band. Ten panelists were allowed to attach and detach the watch 10 times, and evaluated the hardness of the watch band when the watch was put on and the trace of the watch band 10 times after being attached and detached.

  A case where six or more panelists evaluate that “the hardness of the watch band when being worn is moderate and cannot be seen after the watch band is removed after being removed” is regarded as acceptable. Otherwise, it will be rejected.

(Watch band production test)
A watch band was manufactured by injection molding a polyurethane composition for a watch. At this time, 24 parts by mass of 100 parts by mass of the timepiece polyurethane composition becomes a waste material, and a composition obtained by adding 76 parts by mass of a new material of the timepiece polyurethane composition to 24 parts by mass of this waste material. Was used to produce a watch band by injection molding (recycled product (1)). Furthermore, in the production of the recycled product (1), 24 parts by mass of 100 parts by mass of the polyurethane composition for watches is a waste material, and 76 parts by mass of a new material for the polyurethane composition for watches with respect to 24 parts by mass of this waste material. A watch band was produced by injection molding using the composition obtained by adding (recycled product (2)). The same procedure was repeated, and further, from recycled product (3) to recycled product (7). The above-mentioned water resistance test (after 20 days) was performed on the recycled products (1) to (7).

For all the recycled products (1) to (7), a case where the decrease rate of the maximum value of the tensile strength in the water resistance test (after 20 days) is 5% or less is regarded as acceptable. Otherwise, it will be rejected.
In the production of an actual industrial watch band, the waste material is continuously mixed with the new material and injection molding is performed. In the 4th cycle after mixing the waste material, the ratio of the waste material generated in the first cycle in the composition is usually 3% or less, and in the seventh cycle, the waste material generated in the first cycle in the composition. The ratio is usually at the impurity level. For this reason, if it is a composition that satisfies the above acceptance criteria (that is, a composition in which the reduction rate of the maximum value of the tensile strength in the water resistance test (after 20 days) is 5% or less in the recycled product (7)). In the production of an industrial watch band, it is considered that the quality of the watch band is not deteriorated even when the waste material is continuously mixed with the new material and injection molding is performed.

<Preparation of polyurethane component (A)>
[Preparation Example 1]
Polymerization was carried out using hexamethylene diisocyanate as the diisocyanate component and polyhexamethylene carbonate diol and polycaprolactone diol as the diol component to synthesize polyurethane (A1). The obtained pellet-shaped polyurethane (A1) is composed of 16 mol% of the structural unit (a1) derived from hexamethylene diisocyanate, 56 mol% of the structural unit (a2-1) derived from polyhexamethylene carbonate diol, The structural unit (a2-2) derived from caprolactone diol was contained in an amount of 28 mol%. The hardness was 91 and the tensile strength was 20 MPa or more.

[Preparation Example 2]
Polymerization was performed using hexamethylene diisocyanate as the diisocyanate component, and poly (3-methyl-1,5-pentylene carbonate) diol and polytetramethylene glycol as the diol component to synthesize polyurethane (A2). The obtained pellet-like polyurethane (A2) has 17 mol% of the structural unit (a1) derived from hexamethylene diisocyanate and the structural unit (a2) derived from poly (3-methyl-1,5-pentylene carbonate) diol. -1) was contained in an amount of 75 mol% and structural units derived from polytetramethylene glycol (a2-3) in an amount of 8 mol%. The hardness was 85 and the tensile strength was 20 MPa or more.

[Preparation Example 3-1]
90 parts by mass of the polyurethane (A1) obtained in Preparation Example 1 and 10 parts by mass of the polyurethane (A2) obtained in Preparation Example 2 were mixed to obtain a polyurethane component (A3-1). The obtained pellet-shaped polyurethane component (A3-1) is derived from 16 mol% of the structural unit (a1) derived from diisocyanate, 58 mol% of the structural unit (a2-1) derived from diol, and from the diol. The total of structural units (a2-2) and (a2-3) was included in an amount of 26 mol%. The hardness was 90, and the tensile strength was 20 MPa or more.

[Preparation Example 3-2]
80 parts by mass of the polyurethane (A1) obtained in Preparation Example 1 and 20 parts by mass of the polyurethane (A2) obtained in Preparation Example 2 were mixed to obtain a polyurethane component (A3-2). The obtained pellet-shaped polyurethane component (A3-2) is derived from 16 mol% of the structural unit (a1) derived from diisocyanate, 60 mol% of the structural unit (a2-1) derived from diol, and from the diol. The total of structural units (a2-2) and (a2-3) was included in an amount of 24 mol%. The hardness was 90, and the tensile strength was 20 MPa or more.

[Preparation Example 3-3]
50 parts by mass of the polyurethane (A1) obtained in Preparation Example 1 and 50 parts by mass of the polyurethane (A2) obtained in Preparation Example 2 were mixed to obtain a polyurethane component (A3-3). The obtained pellet-shaped polyurethane component (A3-3) is derived from 17 mol% of the structural unit (a1) derived from diisocyanate, 65 mol% of the structural unit (a2-1) derived from diol, and derived from the diol. The total of structural units (a2-2) and (a2-3) was included in an amount of 18 mol%. The hardness was 88 and the tensile strength was 20 MPa or more.

[Preparation Example 3-4]
30 parts by mass of the polyurethane (A1) obtained in Preparation Example 1 and 70 parts by mass of the polyurethane (A2) obtained in Preparation Example 2 were mixed to obtain a polyurethane component (A3-4). The obtained pellet-shaped polyurethane component (A3-4) is derived from 17 mol% of the structural unit (a1) derived from diisocyanate, 69 mol% of the structural unit (a2-1) derived from diol, and derived from the diol. The total of structural units (a2-2) and (a2-3) was included in an amount of 14 mol%. The hardness was 87 and the tensile strength was 20 MPa or more.

[Preparation Example 3-5]
10 parts by mass of the polyurethane (A1) obtained in Preparation Example 1 and 90 parts by mass of the polyurethane (A2) obtained in Preparation Example 2 were mixed to obtain a polyurethane component (A3-5). The obtained pellet-shaped polyurethane component (A3-5) is derived from 17 mol% of the structural unit (a1) derived from diisocyanate, 73 mol% of the structural unit (a2-1) derived from diol, and derived from the diol. The sum of structural units (a2-2) and (a2-3) was included in an amount of 10 mol%. The hardness was 86 and the tensile strength was 20 MPa or more.
(GPC measurement)
The polyurethane component (A3-2) obtained in Preparation Example 3-2 was used as the polyurethane component (A), and for the additive (B), tinuvin 234 (trade name, Ciba Specialty) was used as the ultraviolet absorber (B1). Chemicals), Irganox 1010 (trade name, manufactured by Ciba Geigy) as hindered phenol antioxidant (B2), 44'-butylidenebis (3-methyl-6-t-butylphenyl) as phosphorus stabilizer (B3) ^Ditridecyl phosphite) (R ^{b321 to} R ^b324 = tridecyl group, R ^b325 , R ^b327 = methyl group, R ^b326 , R ^b328 = t-butyl group, R ^b3291 = hydrogen atom, R ^b3292 = n-propyl group), Bis (2,2,6,6-tetramethyl-1- (octyloxy) piperidine-4-decanedioic acid as a hindered amine stabilizer (B4) Yl) (R ^b41 , R ^b42 = n-octyl group, R ^b43 = 1,8-octylene group), and ^carbodilite LA-1 (trade name, manufactured by Nisshinbo Chemical Co., Ltd.) was used as the carbodiimide-based ^rebinding agent (B5). . With respect to 100 parts by mass of this polyurethane (A3-2), the ultraviolet absorber (B1), the hindered phenol antioxidant (B2), the phosphorus stabilizer (B3), and the hindered amine stabilizer. Using (B4) 0.1 parts by mass and a mixture obtained by adding 0.5 parts by mass of the carbodiimide rebinding agent (B5), the gel permeation chromatography method (GPC method), The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polyurethane component (A3-2) were determined under the following conditions.
-Measuring device: Pump: LC-20AD manufactured by Shimadzu Corporation
Column oven: CO-8020 manufactured by Tosoh Corporation
Autosampler: AS-802 manufactured by Tosoh Corporation
-GPC column structure: Showa Denko Co., Ltd. Shodex (registered trademark) HFIP-G (1), HFIP-606M (2) connected-Injection amount: 0.02 mL
・ Flow rate: 0.2mL / min
Column temperature: 40.0 ° C
・ Sample concentration: 5mg / 5mL
-Mobile phase solvent: hexafluoroisopropanol
(5 mM sodium trifluoroacetate)
Detector: RI (differential refractive index detector), Showa Denko Co., Ltd. RI-104 type, sensitivity 32
Standard sample: Monodispersed polymethyl methacrylate manufactured by Showa Denko KK As a result, the polyurethane component (A3-2) had an Mw of 62,300 and a molecular weight distribution (Mw / Mn) of 2.61.

<Preparation of timepiece polyurethane composition>
[Example 1]
Only the polyurethane (A1) obtained in Preparation Example 1 was used as the polyurethane component (A), and the additive (B) was Tinuvin 234 (trade name, manufactured by Ciba Specialty Chemicals Co., Ltd.) as the ultraviolet absorber (B1). ), Irganox 1010 (trade name, manufactured by Ciba Geigy) as hindered phenol antioxidant (B2), and 44′-butylidenebis (3-methyl-6-tert-butylphenyl ditridecylphosphine as phosphorus stabilizer (B3) Phyto) (R ^{b321 to} R ^b324 = tridecyl group, R ^b325 , R ^b327 = methyl group, R ^b326 , R ^b328 = t-butyl group, R ^b3291 = hydrogen atom, R ^b3292 = n-propyl group), hindered amine-based stability Bis (2,2,6,6-tetramethyl-1- (octyloxy) piperidin-4-yl decanodioate as the agent (B4) ) (R ^b41 , R ^b42 = n-octyl group, R ^b43 = 1,8-octylene group), and ^carbodilite LA-1 (trade name, manufactured by Nisshinbo Chemical Co., Ltd.) was used as the carbodiimide-based ^rebinding agent (B5). With respect to 100 parts by mass of the polyurethane (A1), the ultraviolet absorber (B1), the hindered phenol antioxidant (B2), the phosphorus stabilizer (B3), and the hindered amine stabilizer (B4). ) And 0.1 part by mass of the above carbodiimide rebinding agent (B5) were added and mixed to obtain a polyurethane composition for watch (1). The timepiece polyurethane composition (1) had a hardness of 91 and a tensile strength of 20 MPa or more.

[Example 2]
Polyurethane for watches in the same manner as in Example 1 except that only the polyurethane (A2) obtained in Preparation Example 2 was used instead of only the polyurethane (A1) obtained in Preparation Example 1 as the polyurethane component (A). A composition (2) was obtained. The timepiece polyurethane composition (2) had a hardness of 85 and a tensile strength of 20 MPa or more.

[Example 3-1]
Similar to Example 1 except that instead of only the polyurethane component (A1) obtained in Preparation Example 1 as the polyurethane component (A), the polyurethane component (A3-1) obtained in Preparation Example 3-1 was used. Thus, a timepiece polyurethane composition (3-1) was obtained. The timepiece polyurethane composition (3-1) had a hardness of 90 and a tensile strength of 20 MPa or more.

[Example 3-2]
Similar to Example 1 except that instead of only the polyurethane component (A1) obtained in Preparation Example 1 as the polyurethane component (A), the polyurethane component (A3-2) obtained in Preparation Example 3-2 was used. Thus, a timepiece polyurethane composition (3-2) was obtained. The polyurethane composition for watch (3-2) had a hardness of 90 and a tensile strength of 20 MPa or more.

[Example 3-3]
Similar to Example 1 except that instead of only the polyurethane component (A1) obtained in Preparation Example 1 as the polyurethane component (A), the polyurethane component (A3-3) obtained in Preparation Example 3-3 was used. Thus, a timepiece polyurethane composition (3-3) was obtained. The timepiece polyurethane composition (3-3) had a hardness of 88 and a tensile strength of 20 MPa or more.

[Example 3-4]
As polyurethane component (A), instead of only polyurethane component (A1) obtained in Preparation Example 1, polyurethane component (A3-4) obtained in Preparation Example 3-4 was used. Thus, a timepiece polyurethane composition (3-4) was obtained. The timepiece polyurethane composition (3-4) had a hardness of 87 and a tensile strength of 20 MPa or more.

[Example 3-5]
Similar to Example 1 except that instead of the polyurethane component (A1) obtained in Preparation Example 1 as the polyurethane component (A), the polyurethane component (A3-5) obtained in Preparation Example 3-5 was used. Thus, a timepiece polyurethane composition (3-5) was obtained. The timepiece polyurethane composition (3-5) had a hardness of 86 and a tensile strength of 20 MPa or more.

[Comparative Example 1]
Desmopan (trade name, manufactured by Bayer) was used as a conventional polyurethane composition for watches including an ether-based polyurethane and an additive.

<Evaluation results>
The polyurethane (A1) obtained in Preparation Example 1, the timepiece polyurethane composition obtained in Examples 1, 2, and 3-1 to 3-5 and the timepiece polyurethane composition of Comparative Example 1 are described above. The results of the evaluation method are shown below.

  (Water resistance test)

ポリウレタン（Ａ１）のみから得られた試験片は、引張強度の最大値が水に浸けた時間に対して直線的に低下しており、経時的に劣化していくことが分かった。なお、ポリウレタン（Ａ２）（上述した調製例２）のみから得られた試験片についても、ポリウレタン（Ａ１）のみから得られた試験片と同じ結果となると考える。

It was found that the test piece obtained from only the polyurethane (A1) had a maximum tensile strength that decreased linearly with respect to the time of immersion in water and deteriorated with time. In addition, it is considered that the test piece obtained only from the polyurethane (A2) (Preparation Example 2 described above) has the same result as the test piece obtained from the polyurethane (A1) alone.

  On the other hand, since the test pieces of Examples 1, 2, 3-1 to 3-5 are a combination of a specific polyurethane component (A) and a specific additive (B), they are tensile even if a water resistance test is performed. It was found that the maximum value of strength did not decrease and was excellent in durability.

  In addition, the test piece of Comparative Example 1 was cracked after 10 days, and was shabby after 15 days and 20 days. For this reason, the tensile strength could not be measured for the test pieces after 10, 15, and 20 days.

  (Heat resistance test)

ポリウレタン（Ａ１）のみから得られた試験片は、引張強度の最大値が炉に入れた時間に対して直線的に低下しており、経時的に劣化していくことが分かった。なお、ポリウレタン（Ａ２）（上述した調製例２）のみから得られた試験片についても、ポリウレタン（Ａ１）のみから得られた試験片と同じ結果となると考える。

It was found that the test piece obtained from only the polyurethane (A1) had a maximum tensile strength that decreased linearly with respect to the time when it was placed in the furnace, and deteriorated with time. In addition, it is considered that the test piece obtained only from the polyurethane (A2) (Preparation Example 2 described above) has the same result as the test piece obtained from the polyurethane (A1) alone.

  On the other hand, the test pieces of Examples 1, 2 and 3-1 to 3-5 are a polyurethane component (A) containing a specific structural unit (particularly the structural unit (a2-1)) and a specific additive. Since (B) was combined, it was found that even when a heat resistance test was performed, the maximum value of tensile strength did not decrease and the durability was excellent.

  (Light resistance test)

実施例１、２、３−１〜３−５の試験片は、特定の構造単位を特定の割合で含むポリウレタン成分（Ａ）と特定の添加剤（Ｂ）とを組み合わせているため、耐光性試験を行っても色は変化せず、耐久性に優れることが分かった。

Since the test pieces of Examples 1, 2, 3-1 to 3-5 combine the polyurethane component (A) containing a specific structural unit at a specific ratio and the specific additive (B), the light resistance It was found that the color did not change even when the test was performed and the durability was excellent.

(Watch band wearing test)
For Example 1, 7 out of 10 panelists evaluated that the watchband was moderately hard and that no marks were seen after the watchband was removed. On the other hand, 3 out of 10 panelists evaluated that the watch band was too hard and that no trace was seen after removing the watch band.

  For Example 2, 7 out of 10 panelists evaluated that the watchband was moderately hard and that no marks were seen after the watchband was removed. On the other hand, 3 out of 10 panelists evaluated that the watch band was too soft and that there was no trace after removing the watch band.

Regarding Examples 3-1 to 3-5, all 10 panelists evaluated that the watch band had an appropriate hardness and no marks were observed after removal.
For Comparative Example 1, all 10 panelists evaluated that the watch band was moderately hard and that no marks were seen after the watch band was removed.
Thus, all of Examples 1, 2, 3-1 to 3-5, and Comparative Example 1 passed the results of the watch band wearing test.

(Watch band production test)
For the recycled products (1) of Examples 1, 2, 3-1 to 3-5, the decrease rate (%) of the maximum value of the tensile strength in the test piece after 20 days of the water resistance test is 0%. The color change in the test piece after 20 days of the water resistance test was not observed, and it remained white. The same results as the recycled product (1) were obtained for the recycled products (2) to (7).

  For the recycled product (1) of Comparative Example 1, the test piece after 20 days of the water resistance test was shabby, and the reduction rate (%) of the maximum value of the tensile strength could not be measured. After 20 days of the water resistance test The color of the test piece changed to brown.

Thus, in all of Examples 1, 2, and 3-1 to 3-5, the results of the watch band mounting test were acceptable, but in Comparative Example 1, the results of the watch band wearing test were unacceptable. It was.
In addition, about the comparative example 1, the watch band using the composition obtained by adding 95 mass parts of new materials of the polyurethane composition for timepieces with respect to 5 mass parts of waste materials was also produced (recycled product (1 ')). ). Even for recycled products (1 ') with reduced use of waste materials, the specimens after 10 days of water resistance test are shabby, and the reduction rate (%) of the maximum value of tensile strength cannot be measured. The color of the test piece after 10 days of the water resistance test was changed to brown.

Claims (7)

The structural unit (a1) represented by the following general formula (a1) derived from diisocyanate, the structural unit (a2-1) represented by the following general formula (a2-1) derived from diol, and the following general derived from diol A polyurethane component comprising at least one selected from the structural unit (a2-2) represented by the formula (a2-2) and the structural unit (a2-3) represented by the following general formula (a2-3) derived from a diol ( A) and
At least one phosphorus-based stabilization selected from an ultraviolet absorber (B1), a hindered phenol-based antioxidant (B2), a neutral phosphate ester (B3-1), and a neutral phosphite ester (B3-2) An additive (B) consisting of an agent (B3), a hindered amine stabilizer (B4) and a carbodiimide rebinding agent (B5),
The polyurethane component (A) is 10 to 25 mol% of the structural unit (a1) and the structural unit (a2-1) with respect to the total of 100 mol% of the structural units (a1) and (a2-1) to (a2-3). ), And a total of the structural units (a2-2) and (a2-3) in an amount of 3 to 35 mol%.

(In the formula (a1), R ^a1 represents a divalent saturated aliphatic hydrocarbon group having 3 to 8 carbon atoms.)

(In formula (a2-1), R ^a21 represents a divalent saturated aliphatic hydrocarbon group having 4 to 10 carbon atoms.)

(In formula (a2-2), R ^a22 represents a divalent saturated aliphatic hydrocarbon group having 3 to 6 carbon atoms.)

(In formula (a2-3), R ^a23 represents a divalent saturated aliphatic hydrocarbon group having 2 to 6 carbon atoms.) The neutral phosphate ester (B3-1) is represented by the following formula (b3-1), and the neutral phosphite ester (B3-2) is represented by the following formula (b3-2). The timepiece polyurethane composition according to claim 1.

(In formula (b3-1), R ^{b311 to} R ^b314 each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, and R ^{b315 to} R ^b318 each independently represents 1 carbon atom. ^Represents a linear or branched alkyl group of ^˜6 , R ^b3191 and R ^b3192 each independently represents a hydrogen atom or a linear or branched alkyl group of 1 to 5 carbon atoms, and R ^{b3191 And} the total number of carbon atoms of R ^b3192 is 1 to 5.)

(In formula (b3-2), R ^{b321 to} R ^b324 each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, and R ^{b325 to} R ^b328 each independently represents 1 carbon atom. ^Represents a linear or branched alkyl group of ^˜6 , R ^b3291 and R ^b3292 each independently represent a hydrogen atom or a linear or branched alkyl group of 1 to 5 carbon atoms, and R ^{b3291 And} the total number of carbon atoms of R ^b3292 is 1 to 5.) The watch polyurethane composition according to claim 1 or 2, wherein the hindered amine stabilizer (B4) is represented by the following formula (b4).

(In formula (b4), R ^b41 and R ^b42 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and R ^b43 represents a divalent aliphatic carbon atom having 1 to 10 carbon atoms. Represents a hydrogen group.)   The timepiece polyurethane composition according to any one of claims 1 to 3, wherein the ultraviolet absorber (B1) is a benzotriazole ultraviolet absorber.   The ultraviolet absorber (B1), the hindered phenol antioxidant (B2), the phosphorus stabilizer (B3), the hindered amine stabilizer (B4) and the carbodiimide rebinding agent (B5) are added to the polyurethane component (A 5) The polyurethane composition for a timepiece according to any one of claims 1 to 4, wherein the polyurethane composition is contained in an amount of 0.01 to 5.0 parts by mass with respect to 100 parts by mass.   A timepiece band obtained from the polyurethane composition for timepieces according to any one of claims 1 to 5.   A timepiece comprising the timepiece band according to claim 6.