Composition for soft materials, and soft material

Abstract

The present invention aims to provide a composition for soft materials, which enables production of a soft material excellent in transparency, a stress relaxation property, and strength and having an elongation property that is not so much lowered even at high temperatures. The present invention also aims to provide a soft material produced using the composition for soft materials of the present invention. The present invention relates to a composition for soft materials including polyrotaxane and a radical polymerizable monomer, the polyrotaxane including a cyclic molecule, a linear molecule threading through a cavity of the cyclic molecule in a skewered manner, and capping groups that cap both ends of the linear molecule, the polyrotaxane having at least one cyclic molecule with a radical polymerizable group, the polyrotaxane having at least two radical polymerizable groups.

Claims

1. A polyrotaxane-containing composition comprising: polyrotaxane; and a radical polymerizable monomer, wherein the polyrotaxane comprises: a cyclic molecule; a linear molecule threading through a cavity of the cyclic molecule in a skewered manner; and capping groups that cap both ends of the linear molecule, of the polyrotaxane has at least two radical polymerizable groups and comprises at least one cyclic molecule having the radical polymerizable group, the radical polymerizable group in the polyrotaxane is a (meth)acryloyl group, and the radical polymerizable monomer comprises a one-functional radical polymerizable monomer having a single radical polymerizable group in a molecule of the one-functional radical polymerizable monomer.

2. A polyrotaxane-containing material produced from the polyrotaxane-containing composition according to claim 1.

3. The polyrotaxane-containing composition according to claim 1, wherein an amount of the radical polymerizable monomer is in a range from 35 to 99.8% by mass relative to an amount of the composition.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 are each a schematic diagram illustrating an exemplary structure of a soft material produced using the composition for soft materials of the present invention.

DESCRIPTION OF EMBODIMENTS

(2) The present invention is specifically described in the following with reference to, but not limited to, examples. It is to be noted that polyrotaxane used in production examples were prepared in accordance with the method disclosed in Patent Literature 1.

Production Example 1

(3) Polyrotaxane (inclusion rate of cyclic molecule: 25%) prepared had polyethylene glycol (mass average molecular weight: 35000) as a linear molecule, -cyclodextrin (substitution degree of hydroxypropyl group: 49%, polymerization degree of polycaprolactone: 4.1) that was preliminary subjected to introduction of a hydroxypropyl group followed by graft polymerization of -caprolactone, as a cyclic molecule, and an adamantaneamine group as a capping group. The polyrotaxane was dissolved in xylene to prepare 300 g of a 35% by mass solution. To the solution, 60 mg of 4-methoxyphenol was added as a polymerization inhibitor. The mixture was stirred at room temperature until 4-methoxyphenol was completely dissolved therein. To the solution, 19.1 g of 2-methacryloyloxyethyl isocyanate was added. After stirring for 30 minutes, the mixture was warmed to 60 C. and allowed to react for 4 hours. The obtained reaction solution was cooled to room temperature and added to a large amount of methanol. The mixture was stirred and a resulting precipitate was taken out by centrifugation. The obtained precipitate was dissolved in a large amount of acetone and then added to a large amount of methanol. The mixture was stirred for reprecipitation, and the precipitate was taken out by centrifugation. The obtained precipitate was dried to give 117.9 g of polyrotaxane (PR-1) having a methacryloyloxy ethyl carbamoyl group as a (meth)acryloyl group that is a radical polymerizable group in a cyclic molecule and having two or more radical polymerizable groups. The introduction rate of the radical polymerizable groups in the obtained polyrotaxane (PR-1) was calculated by the calculation method described above. As a result, the introduction rate of the methacryloyloxy ethyl carbamoyl group (radical polymerizable group) in the polyrotaxane (PR-1) was 79%.

Production Example 2

(4) Polyrotaxane (PR-2) (106.2 g) having a methacryloyloxy ethyl carbamoyl group as a (meth)acryloyl group that is a radical polymerizable group in a cyclic molecule and having two or more radical polymerizable groups was obtained in the same manner as in Production example 1, except that the amount of 2-methacryloyloxyethyl isocyanate was changed to 7.2 g. The introduction rate of the radical polymerizable groups in the obtained polyrotaxane (PR-2) was calculated in the same manner as in Production example 1. As a result, the introduction rate of the methacryloyloxy ethyl carbamoyl group (radical polymerizable group) in the polyrotaxane (PR-2) was 30%.

Production Example 3

(5) Polyrotaxane (PR-3) (101.8 g) having a methacryloyloxy ethyl carbamoyl group as a (meth)acryloyl group that is a radical polymerizable group in a cyclic molecule and having two or more radical polymerizable groups was obtained in the same manner as in Production example 1, except that the amount of 2-methacryloyloxyethyl isocyanate was changed to 2.4 g. The introduction rate of the radical polymerizable groups in the obtained polyrotaxane (PR-3) was calculated in the same manner as in Production example 1. As a result, the introduction rate of the methacryloyloxy ethyl carbamoyl group (radical polymerizable group) in the polyrotaxane (PR-3) was 11%.

Production Example 4

(6) Polyrotaxane (inclusion rate of cyclic molecule: 25%) prepared had polyethylene glycol (mass average molecular weight: 35000) as a linear molecule, -cyclodextrin (substitution degree of hydroxypropyl group: 49%, polymerization degree of polycaprolactone: 4.1) that was preliminary subjected to introduction of a hydroxypropyl group followed by graft polymerization of -caprolactone, as a cyclic molecule, and an adamantaneamine group as a capping group. The polyrotaxane was dissolved in xylene to prepare 300 g of a 35% by mass solution. The solution was added to a large amount of methanol. The mixture was stirred and a precipitate was taken out by centrifugation. The obtained precipitate was dissolved in a large amount of acetone, and the resulting solution was added to a large amount of methanol. The mixture was stirred for reprecipitation, and the precipitate was taken out by centrifugation. The obtained precipitate was dried to give 99.8 g of polyrotaxane (PR-4) not having a radical polymerizable group.

Examples 1 to 16, Comparative Examples 1 to 18

(7) A 30-mL sample bottle equipped with a stirrer was charged with materials in accordance with the formulation shown in Tables 1 and 2. The mixture was stirred at 25 C. for one hour to give a homogeneous solution. To the obtained solution, 2,2-azobisisobutylonitrile was added as a polymerization initiator. The mixture was stirred at 25 C. for 30 minutes and then subjected to ultrasonic treatment for 3 minutes to give a composition for soft materials. The obtained composition for soft materials was sufficiently deaerated and filled into a glass mold having a diameter of 80 mm and a thickness of 2 mm. The composition was heated at 60 C. for 10 hours to complete the polymerization reaction, and released from the mold. A soft material was thus obtained.

(8) In Tables 1 and 2, MMA means methyl methacrylate (produced by KANTO CHEMICAL CO., INC.), 2-EHA means 2-ethyl hexyl acrylate (produced by Tokyo Chemical Industry Co., Ltd.), BA means n-butyl acrylate (produced by Tokyo Chemical Industry Co., Ltd.), EA means ethyl acrylate (produced by Tokyo Chemical Industry Co., Ltd.), MEA means 2-methoxyethyl acrylate (produced by Tokyo Chemical Industry Co., Ltd.), TEGDMA means triethylene glycol dimethacrylate (produced by Tokyo Chemical Industry Co., Ltd.), TMPTA means trimethylolpropane triacrylate (produced by SHIN-NAKAMURA CHEMICAL CO., LTD.), MBAA means N,N-methylenebisacrylamide (produced by Tokyo Chemical Industry Co., Ltd.), ATBC means acetyl tributyl citrate (produced by Tokyo Chemical Industry Co., Ltd.), and AIBN means 2,2-azobisisobutylonitrile (produced by Wako Pure Chemical Industries, Ltd).

(9) TABLE-US-00001 TABLE 1 Polyrotaxane having Polymerization two or more radical Radical polymerizable monomer Plasticizer initiator polymerizable groups (g) (g) (mg) (g) MMA 2-EHA BA EA MEA ATBC AIBN Example 1 PR-1 0.0892 4.00 6.00 1.784 22.4 Example 2 PR-1 0.2050 4.00 6.01 1.784 22.5 Example 3 PR-1 0.4171 4.01 6.00 1.784 22.3 Example 4 PR-1 0.6183 4.00 6.00 1.784 22.6 Example 5 PR-2 0.0892 4.00 6.00 1.784 22.4 Example 6 PR-2 0.6181 4.00 6.00 1.784 22.2 Example 7 PR-3 0.6180 4.00 6.00 1.784 22.4 Example 8 PR-1 0.0891 4.00 6.00 22.4 Example 9 PR-1 0.2053 4.00 6.01 22.3 Example 10 PR-2 0.0892 4.00 6.00 22.4 Example 11 PR-3 0.6182 4.00 6.02 22.5 Example 12 PR-1 0.0891 2.00 8.00 1.784 19.8 Example 13 PR-1 0.2051 2.01 8.00 1.784 19.6 Example 14 PR-1 0.0892 4.00 6.00 1.784 26.5 Example 15 PR-1 0.2051 4.01 6.00 1.784 26.5 Example 16 PR-1 0.0892 4.02 6.00 1.784 26.6

(10) TABLE-US-00002 TABLE 2 Conventional Polymerization crosslinking Radical polymerizable monomer Plasticizer initiator agent (g) (g) (mg) (g) MMA 2-EHA BA EA MEA ATBC AIBN Comparative TEGDMA 0.0402 4.00 6.00 1.784 22.5 Example 1 Comparative TEGDMA 0.0893 4.00 6.00 1.784 22.4 Example 2 Comparative TEGDMA 0.2053 4.00 6.01 1.784 22.8 Example 3 Comparative TMPTA 0.0163 4.00 6.00 1.784 22.3 Example 4 Comparative TMPTA 0.0276 4.01 6.00 1.784 22.4 Example 5 Comparative TMPTA 0.0616 4.00 6.00 1.784 22.5 Example 6 Comparative TMPTA 0.1414 4.00 6.00 1.784 22.6 Example 7 Comparative MBAA 0.0321 4.01 6.00 1.784 22.5 Example 8 Comparative PR-4 0.0893 4.00 6.00 1.784 22.4 Example 9 Comparative TEGDMA 0.0403 4.00 6.00 22.4 Example 10 Comparative TEGDMA 0.0892 4.00 6.00 22.6 Example 11 Comparative TEGDMA 0.2050 4.01 6.01 22.8 Example 12 Comparative TEGDMA 0.0400 2.00 8.00 1.784 19.5 Example 13 Comparative TEGDMA 0.0892 2.02 8.01 1.784 19.7 Example 14 Comparative TEGDMA 0.2054 2.00 8.00 1.784 19.9 Example 15 Comparative TEGDMA 0.0402 4.00 6.00 1.784 26.6 Example 16 Comparative TEGDMA 0.0892 4.00 6.02 1.784 27.0 Example 17 Comparative TEGDMA 0.0402 4.00 6.02 1.784 26.6 Example 18

Comparative Example 19

(11) A urethane composition for soft materials was produced in the same manner as in Example 1 of Patent Literature 1. The production method is specifically described in the following.

(12) (Preparation of Polyrotaxane (A-1) not having a Radical Polymerizable Group)

(13) A compound (hereafter, also referred to as HAPR35) containing polyrotaxane (inclusion rate of cyclic molecule: 25%) was prepared in the same manner as in the method disclosed in WO 05/080469. The polyrotaxane had polyethylene glycol (mass average molecular weight: 35000) as a linear molecule and -cyclodextrin as a cyclic molecule, and an adamantaneamine group as a capping group, and part of hydroxy groups of the -cyclodextrin was further hydroxypropylated (-cyclodextrin inclusion rate: 25%, Substitution degree of hydroxypropyl group: 49%).

(14) An amount of 20 g of HAPR35 was charged into a three-neck flask and 90 g of -caprolactone was introduced thereinto under a gentle stream of nitrogen. The contents were homogeneously stirred with a mechanical stirrer at 100 C. for 60 minutes, and 6 g of tin 2-ethylhexanoate (50% by mass solution) preliminary diluted in toluene was added thereto. The resulting product was reacted for 5 hours, and the solvent was removed therefrom. Thus, polyrotaxane (A-1) not having a radical polymerizable group was prepared.

(15) (Preparation of Crosslinking Agent B-1)

(16) An amount of 28.0 g of 1,3-bis(isocyanatomethyl)cyclohexane (produced by Mitsui Chemicals, Inc., Takenate 600) was charged into a 200-mL reaction vessel and heated to 80 C. with stirring under a stream of nitrogen. An amount of 49.8 g of polycarbonate diol (produced by Asahi Kasei Chemicals Corporation, DURANOL T-5650J) was warmed to 70 C. and then slowly added dropwise to the reaction vessel over 4 hours. The mixture was further stirred for 3 hours to give polycarbonate having isocyanate groups at both ends.

(17) An amount of 77.78 g of the obtained polycarbonate having isocyanate groups at both ends was charged into a 200-mL reaction vessel, and then heated to 100 C. with stirring under a stream of nitrogen. An amount of 20.38 g of -caprolactam was added thereto, and the mixture was stirred for 6 hours to give a crosslinking agent B-1 in which isocyanate groups at both ends of polycarbonate were protected by -caprolactam. The measurement with an FT-IR clarified that the peak derived from an isocyanate group at around 2250 cm.sup.1 disappeared, thereby confirming the protection of the isocyanate groups.

(18) (Preparation of Composition for Soft Materials)

(19) A reaction vessel was charged with 32.2 g of polyrotaxane (A-1) not having a radical polymerizable group, 46.0 g of the crosslinking agent B-1, 29.4 g of polycarbonate diol (produced by Asahi Kasei Chemicals Corporation, DURANOL T-5650)), 11.0 mg of dibutyl tin dilaurate as a deprotection catalyst, and 2.11 g of 2,4-bis(dodecylthiomethyl)-6-methyl phenol (produced by BASF SE, Irganox1726) as a stabilizer. The contents were heated to 80 C. and stirred to give a homogeneous solution. The solution was defoamed under reduced pressure to give a urethane composition for soft materials.

(20) (Preparation of Soft Material)

(21) The obtained composition for soft materials were sufficiently deaerated and filled into a glass mold having a diameter of 80 mm and a thickness of 2 mm. The composition was heated at 150 C. for 5 hours to complete the polymerization reaction, and released from the mold. A soft material was thus obtained.

Comparative Example 20

(22) A urethane composition for soft materials was prepared in the same manner as in Example 2 of Patent Literature 1. The production method is specifically described in the following.

(23) (Preparation of Crosslinking Agent B-2)

(24) An amount of 30.0 g of 1,3-bis(isocyanatomethyl)cyclohexane (produced by Mitsui Chemicals, Inc., Takenate 600) was charged into a 200-mL reaction vessel and heated to 80 C. with stirring under a stream of nitrogen.

(25) An amount of 33.2 g of polycarbonate diol (produced by Asahi Kasei Chemicals Corporation, DURANOL T-5650E) was warmed to 70 C. and then slowly added dropwise to the reaction vessel over 2 hours. The mixture was further stirred for 3 hours to give polycarbonate having isocyanate groups at both ends.

(26) An amount of 63.2 g of the obtained polycarbonate having isocyanate groups at both ends was charged into a 200-mL reaction vessel, and then heated to 100 C. with stirring under a stream of nitrogen. An amount of 19.9 g of -caprolactam was added thereto, and the mixture was stirred for 6 hours to give a crosslinking agent B-2 in which isocyanate groups at both ends of polycarbonate were protected by -caprolactam. The measurement with a FT-IR clarified that the peak derived from an isocyanate group at around 2250 cm.sup.1 disappeared, thereby confirming the protection of the isocyanate groups.

(27) (Preparation of Composition for Soft Materials)

(28) A reaction vessel was charged with 30.0 g of polyrotaxane (A-1) not having a radical polymerizable group prepared in the same manner as in Comparative Example 19, 83.1 g of the crosslinking agent B-2, 66.9 g of polycarbonate diol (produced by Asahi Kasei Chemicals Corporation, DURANOLT-5650J), 52 mg of dibutyl tin dilaurate as a deprotection catalyst, and 1.80 g of 2,4-bis(dodecylthiomethyl)-6-methylphenol (produced by BASF SE, Irganox1726). The contents were heated to 80 C. and stirred to give a homogeneous solution. The solution was defoamed under reduced pressure to give a urethane composition for soft materials.

(29) (Preparation of Soft Material)

(30) The obtained composition for soft materials were sufficiently deaerated and filled into a glass mold having a diameter of 80 mm and a thickness of 2 mm. The composition was heated at 150 C. for 5 hours to complete the polymerization reaction, and released from the mold. A soft material was thus obtained.

(31) <Evaluation>

(32) The soft materials obtained in the examples and comparative examples were evaluated for the following items. Tables 3 and 4 show the results.

(33) (Transparency)

(34) The soft materials obtained in the examples and comparative examples were visually checked. The transparency was evaluated based on the following criteria. (good) . . . . The soft material was transparent without coloring or cloudiness (poor) . . . . Coloring or cloudiness was found in the soft material.
(Tensile Test (Breaking Strength, Elongation at Break, and Lowering Rate of Elongation at Break))

(35) From each of the soft materials obtained in the examples and comparative examples, a dumbbell specimen (dumbbell No. 7 as defined in JIS K 6251) was punched. Using the specimen, the tensile test was carried out under the following conditions, thereby obtaining the breaking strength and elongation at break. Device: AUTO GRAPH AG-1000D type (produced by Shimadzu Corporation) Load cell: 50N Measurement temperature: 25 C., 80 C. Intermarker distance: 20 mm Tensile speed: 10 mm/min

(36) The lowering rate of elongation at break was calculated using the following formula wherein the elongation at break at 25 C. was represented by B1 and the elongation at break at 80 C. was represented by B2.
Lowering rate of elongation at break (%)={(B1B2)/B1}100
(Tensile Stress Relaxation Test)

(37) From each of the soft materials obtained in the examples and comparative examples, a dumbbell specimen (dumbbell No. 7 as defined in JIS K 6251) was punched. The tensile stress relaxation test was carried out using the same device as that used in the tensile test. Each specimen was distorted in an amount as shown in Tables 3 and 4 and held for 40 minutes while the distortion was kept. The stress relaxation rate was calculated using the following formula in which the maximum stress value during 40 minutes was represented by B3 and the stress value after a lapse of 40 minutes was represented by B4.
Stress relaxation rate (%)={(B3B4)/B3}100.

(38) TABLE-US-00003 TABLE 3 Tensile test (25 C.) Tensile test (80 C.) Lowering Tensile stress relaxation test Breaking Elongation Breaking Elongation rate of Stress strength at break strength at break elongation Distor- relaxation Transparency (Mpa) (%) (Mpa) (%) at break (%) tion (%) rate (%) Note Example 1 0.45 705 0.45 812 15 400 58.9 MMA:2-EHA = 4:6 Example 2 0.85 471 0.48 437 7 With plasticizer Example 3 1.30 382 0.50 344 10 Example 4 0.82 221 0.56 194 12 75 17.1 Example 5 0.85 890 0.35 928 4 400 56.1 Example 6 1.00 305 0.41 263 14 75 22.2 Example 7 1.30 510 0.29 434 15 Example 8 2.52 501 0.49 812 62 300 27.5 MMA:2-EHA = 4:6 Example 9 3.22 482 0.62 411 15 Without plasticizer Example 10 3.24 453 0.64 942 107 Example 11 3.51 487 0.35 448 8 Example 12 0.22 745 0.17 634 15 400 63.8 MMA:2-EHA = 2:8 Example 13 0.33 425 0.25 418 2 With plasticizer Example 14 0.58 905 0.30 799 12 400 59.7 MMA:BA = 4:6 Example 15 1.12 521 0.45 469 10 With plasticizer Example 16 0.92 770 0.31 641 17 400 53.1 EA:MEA = 4:6 With plasticizer

(39) TABLE-US-00004 TABLE 4 Tensile test (25 C.) Tensile test (80 C.) Lowering Tensile stress relaxation test Breaking Elongation Breaking Elongation rate of Stress strength at break strength at break elongation Distor- relaxation Transparency (Mpa) (%) (Mpa) (%) at break (%) tion (%) rate (%) Note Comparative 0.45 649 0.18 367 43 400 34 MMA:2-EHA = 4:6 Example 1 With plasticizer Comparative 0.59 419 0.35 173 59 Example 2 Comparative 0.47 205 0.21 69 66 75 5.41 Example 3 Comparative 0.12 563 0.10 163 71 Example 4 Comparative 0.45 569 0.21 235 59 400 28.5 Example 5 Comparative 0.63 467 0.31 215 54 Example 6 Comparative 0.5 184 0.19 67 64 Example 7 Comparative 0.27 456 0.11 222 51 Example 8 Comparative X: White 0.13 950 400 75.3 Example 9 turbidness Comparative 2.48 472 0.31 211 55 300 21.1 MMA:2-EHA = 4:6 Example 10 Without plasticizer Comparative 2.51 452 0.35 184 59 300 18.2 Example 11 Comparative 1.71 309 0.30 78 75 Example 12 Comparative 0.11 508 0.07 218 57 400 44.2 MMA:2-EHA = 2:8 Example 13 With plasticizer Comparative 0.14 269 0.08 90 62 Example 14 Comparative 0.12 80 0.08 39 51 Example 15 Comparative 0.58 800 0.33 301 62 400 38.9 MMA:BA = 4:6 Example 16 With plasticizer Comparative 0.61 478 0.34 213 55 Example 17 Comparative 0.9 697 0.30 204 71 400 24.6 EA:MEA = 4:6 Example 18 With plasticizer Comparative X: Yellow 0.9 142 75 2.8 Urethane elastomer Example 19 discoloration Comparative X: Yellow 0.2 245 75 5.1 Example 20 discoloration

(40) In comparison of Examples 1 to 7 and Comparative Examples 1 to 8 wherein similar radical polymerizable monomers and similar plasticizers were used, the soft materials of Examples 1 to 7 in which polyrotaxane including a cyclic molecule that has a radical polymerizable group was used as a crosslinking agent had higher elongation at break and/or higher breaking strength than the soft materials of Comparative Examples 1 to 8 in which a common crosslinking agent was used. The similar results were obtained in comparison of Examples 8 to 11 and Comparative Example 10 to 12, comparison of Examples 12 to 13 and Comparative Examples 13 to 15, and comparison of Examples 14 to 15 and Comparative Examples 16 to 17.

(41) Moreover, the soft materials of Comparative Examples 19 and 20 obtained using urethane compositions for soft materials obviously had lower elongation at break than the soft materials of Examples 16 and 12 which had the similar breaking strength respectively.

(42) In comparison of the stress relaxation rate when the same distortion was given, the soft material of the present invention exhibited a higher stress relaxation rate than the soft material prepared using a common crosslinking agent or the soft material prepared using a urethane composition for soft materials.

(43) In other words, the present invention enables production of the soft material having stress-elongation properties that are hardly achieved by the use of a common crosslinking agent and having both properties of high strength and a high stress relaxation property that are hardly balanced.

INDUSTRIAL APPLICABILITY

(44) The present invention can provide a composition for soft materials, which enables production of a soft material excellent in transparency, a stress relaxation property, and strength and having an elongation property that is not so much lowered even at high temperatures. The present invention can also provide a soft material produced using the composition for soft materials.

REFERENCE SIGNS LIST

(45) 1. Polymer segment derived from radical polymerizable monomer 2. Segment derived from polyrotaxane 3. Linear molecule 4. Cyclic molecule 5. Capping group 6. Crosslinking point