JP6858537B2 - Thermoplastic polyurethane elastomer composition and molded article - Google Patents

Description

The present invention relates to a thermoplastic polyurethane elastomer composition.

Thermoplastic elastomer has rubber-like properties and is excellent in flexibility. Therefore, as an alternative to vulcanized rubber and vinyl chloride resin, molded parts materials such as automobile parts, electronic / electrical equipment parts, and film materials, communication cables, and electric wires It is widely used as a covering material for such materials. Abrasion resistance is required for these molded products, communication cables, electric wires, and the like. Further, for example, when a communication cable coated with a covering material is used for a device such as a robot arm, the communication cable also moves following the operation of this device. Therefore, slidability is also required especially for the outermost layer (sheath) of the communication cable.

As a resin having excellent wear resistance and slidability, for example, Patent Document 1 discloses an olefin-based thermoplastic elastomer composition in which an acrylic-modified organopolysiloxane is mixed with an olefin-based thermoplastic elastomer.

Japanese Patent No. 3437466

By the way, since a communication cable used for a device such as a robot arm is pulled following the operation of the device, elongation and tensile strength are also required.
However, the olefin-based thermoplastic elastomer composition described in Patent Document 1 does not always satisfy the extensibility and tensile strength. Further, although the olefin-based thermoplastic elastomer composition described in Patent Document 1 has a certain degree of slidability, it is not suitable for applications requiring high slidability (for example, for coating a communication cable).

Among the thermoplastic elastomers, the thermoplastic polyurethane elastomer is known to be superior in extensibility and tensile strength as compared with other thermoplastic resins. Instead of the olefin-based thermoplastic elastomer, it is conceivable to add acrylic-modified organopolysiloxane to the thermoplastic polyurethane elastomer to improve the slidability.
However, sufficient slidability could not be obtained by simply blending acrylic-modified organopolysiloxane with a low-hardness thermoplastic polyurethane elastomer.
Further, since the surface of the thermoplastic polyurethane elastomer is easily sticky, it is easy for dirt to adhere to it.
Therefore, there is a demand for a resin material having excellent slidability and antifouling property while maintaining the extensibility and tensile strength which are the characteristics of the thermoplastic polyurethane elastomer.

The present invention has been made in view of the above circumstances, and when it is made into a molded product or when a communication cable or an electric wire is coated, heat having excellent slidability and antifouling property while maintaining elongation and tensile strength. An object of the present invention is to provide a plastic polyurethane elastomer composition.

The present invention has the following aspects.
[1] A thermoplastic polyurethane elastomer, an acrylic-modified organopolysiloxane, and an acrylic gelation accelerator are contained, and the content of the acrylic-modified organopolysiloxane is based on 100 parts by mass of the thermoplastic polyurethane elastomer. A thermoplastic polyurethane elastomer composition having 1 to 100 parts by mass and a content of the acrylic gelation accelerator of 0.1 to 10 parts by mass.

The thermoplastic polyurethane elastomer composition of the present invention is excellent in slidability and antifouling property while maintaining extensibility and tensile strength when it is made into a molded product or when it is coated with a communication cable or an electric wire.

"Thermoplastic polyurethane elastomer composition"
The thermoplastic polyurethane elastomer composition of the present invention contains a thermoplastic polyurethane elastomer, an acrylic-modified organopolysiloxane, and an acrylic gelation accelerator.
Hereinafter, each component will be described.

<Thermoplastic polyurethane elastomer>
As the thermoplastic polyurethane elastomer (hereinafter, also referred to as “TPU”), a block copolymer having a hard segment block and a soft segment block as repeating units is preferable.

The hard segment block is preferably composed of at least diisocyanate and diols.
Examples of the diisocyanate include 1,6-hexamethylene diisocyanate (HDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), isophorone diisocyanate (IPDI), and xylene diisocyanate (XDI). Examples thereof include hydrogenated XDI, tolylene diisocyanate (TDI), triisocyanate, tetramethylxylene diisocyanate (TMXDI), and 1,3,6-hexamethylene triisocyanate.

Examples of diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, and dipropylene glycol. Examples thereof include tripropylene glycol.

The soft segment block is preferably composed of at least a polyol and a diisocyanate.
Examples of the polyol include polyester polyol, polyether polyol, polycarbonate polyol and the like.

Examples of the polyester polyol include a polyester polyol obtained by condensation polymerization of diols and dicarboxylic acid; and a polylactone diol obtained by ring-opening polymerization of a lactone monomer such as ε-caprolactone.
Examples of the diols include the diols exemplified above in the description of the hard segment block.
Examples of the dicarboxylic acid include succinic acid, adipic acid, sebacic acid, phthalic acid, terephthalic acid, isophthalic acid and the like.

Examples of the polyether polyol include a polyether polyol obtained by condensation polymerization of a dicarboxylic acid and a glycol; polyethylene glycol; polypropylene glycol; and polytetramethylene glycol.
Examples of the dicarboxylic acid include the dicarboxylic acid exemplified above in the description of the polyester polyol.
Examples of the glycol include diethylene glycol and a propylene oxide adduct.

Examples of the polycarbonate polyol include a polycarbonate polyol obtained by reacting diols with carbonates; a copolymer of polycaprolactone polyol and polyhexamethylene carbonate, and the like.
Examples of the diols include the diols exemplified above in the description of the hard segment block.
Examples of carbonates include diethylene carbonate and diethyl carbonate.

The hardness of the TPU is not particularly limited, and excellent slidability and antifouling property can be exhibited regardless of whether a high hardness TPU or a low hardness TPU is used.
In the present invention, a shore A hardness of 75 A or less is defined as "low hardness".
The "shore A hardness" is a value measured in accordance with JIS K 6253-: 2012.

Commercially available products can be used as the TPU, for example, "T-8185N", "T-8180N", "T-8175N" manufactured by DIC Cobestropolymer Co., Ltd .; "ET-885" manufactured by BASF Japan Ltd. , "ET-880", "ET870-11V"; "58215", "58315", "2103-70A" manufactured by Lubrizol and the like.

<Acrylic modified organopolysiloxane>
Examples of the acrylic-modified organopolysiloxane include those obtained by copolymerizing an acrylic acid ester with an organopolysiloxane represented by the following general formula (1) by emulsifying graft copolymerization, and an organopolysiloxane represented by the following general formula (1). , Acrylic acid ester and a mixture of this and a copolymerizable monomer are preferably copolymerized with an emulsified graft.

In the above general formula (1), R ¹ , R ² and R ³ are the same or different hydrocarbon groups having 1 to 20 carbon atoms or halogenated hydrocarbon groups having 1 to 20 carbon atoms, respectively.
Examples of the hydrocarbon group having 1 to 20 carbon atoms include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group; and an aryl group such as a phenyl group, a tolyl group, a xsilyl group and a naphthyl group.
Examples of the halogenated hydrocarbon group having 1 to 20 carbon atoms include those in which at least one of the hydrogen atoms bonded to the carbon atom of the hydrocarbon group is replaced with a halogen atom.

In the above general formula (1), Y is an organic group having a radical reactive group, an SH group, or both.
Examples of the radically reactive group include a vinyl group, an allyl group, a γ-acryloxypropyl group, a γ-methacryloxypropyl group, a γ-mercaptopropyl group and the like.

In the above general formula (1), Z ¹ and Z ² are the same or different hydrogen atoms, lower alkyl groups or triorganosilyl groups, respectively.
Examples of the lower alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group and the like.
The triorganosilyl group is represented by the following general formula (2).

In the above general formula (2), R ⁴ and R ⁵ are hydrocarbon groups having the same or different carbon atoms 1 to 20, or halogenated hydrocarbon groups having carbon atoms 1 to 20, respectively, and R ⁶ is a hydrocarbon group having 1 to 20 carbon atoms. It is an organic group having ~ 20 hydrocarbon groups, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a radical reactive group, an SH group, or both.
These organic groups having a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a radical reactive group, an SH group, or both are the above-mentioned R ¹ , R ² , R ³ and In the explanation of Y, the same ones as exemplified above can be mentioned.

Further, in the above general formula (1), m is a positive integer of 10,000 or less, preferably an integer in the range of 500 to 8,000, and n is an integer of 1 or more, preferably 1 to 1. It is an integer in the range of 500.

Examples of the acrylic acid ester emulsified and graft-copolymerized with the organopolysiloxane include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate. Acrylate acrylates such as stearyl acrylates; alkoxyalkyl acrylates such as methoxyethyl acrylates and butoxyethyl acrylates; cyclohexyl acrylates, phenyl acrylates, benzyl acrylates and the like can be mentioned. These are used alone or in combination of two or more.

Examples of the monomer copolymerizable with the acrylic acid ester include hydroxyl group-containing unsaturated monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. These are used alone or in combination of two or more.

The blending ratio ((a) / (b)) of the organopolysiloxane (a) and the acrylic acid ester or the mixture (b) of the acrylic acid ester and the copolymerizable monomer thereof is a mass ratio. 2/8 to 8/2 is preferable, and 4/6 to 7/3 is more preferable.
Further, when a mixture of an acrylic acid ester and a copolymerizable monomer thereof is used as (b), the content of the monomer copolymerizable with the acrylic acid ester is determined with respect to the total mass of the mixture. It is preferably less than 30% by mass.

The acrylic-modified organopolysiloxane is preferably a particulate copolymer forming a core-shell structure, the main component of the core portion is organopolysiloxane (a), and the main component of the shell portion is acrylic acid ester or acrylic acid. It is preferably a mixture (b) of the ester and a copolymerizable monomer thereof.
Here, the "main component" means that the ratio of the core portion or the shell portion to the total mass is 50% by mass or more.

Commercially available products can be used as the acrylic-modified organopolysiloxane having such a core-shell structure. For example, "Charine R-170", "Charine R-170S", and "Charine R-127E" manufactured by Nissin Chemical Industry Co., Ltd. "And so on.

The content of the acrylic-modified organopolysiloxane is 1 to 100 parts by mass, preferably 5 to 80 parts by mass, and more preferably 5 to 50 parts by mass with respect to 100 parts by mass of TPU. When the content of the acrylic-modified organopolysiloxane is 1 part by mass or more, the effect of improving slidability and antifouling property can be obtained. The effect of improving slidability and antifouling property tends to increase as the content of the acrylic-modified organopolysiloxane increases. However, if the content is too high, the acrylic-modified organopolysiloxane tends to aggregate in the TPU. When the acrylic-modified organopolysiloxane aggregates, cracks may occur at the aggregated portion as a base point. In addition, the extensibility and tensile strength are likely to decrease. Further, when a low hardness TPU is used, the strength tends to decrease. Therefore, if the content of the acrylic-modified organopolysiloxane is too high, the thermoplastic polyurethane elastomer composition of the present invention cannot withstand the stress at the time of pressure molding or mold release, and the molded product may be broken. It becomes difficult to obtain. When the content of the acrylic-modified organopolysiloxane is 100 parts by mass or less, it is possible to suppress the aggregation of the acrylic-modified organopolysiloxane in the TPU, so that cracks are unlikely to occur. In addition, good extensibility and tensile strength can be maintained. In addition, even if a TPU having a low hardness is used, the resistance to stress during pressure molding and mold release is enhanced, so that fracture is unlikely to occur, and a molded product can be easily manufactured.

<Acrylic gelling accelerator>
The acrylic gelation accelerator forms a pseudo-crosslinked state by being entangled with the molecular chain of TPU to develop melt elasticity.
The thermoplastic polyurethane elastomer composition can be obtained by kneading TPU, an acrylic-modified organopolysiloxane, and an acrylic gelation accelerator using a kneader or the like. At this time, if the melt elasticity of the TPU is increased, a shearing force is likely to be applied to the kneaded product at the time of kneading. As a result, an external force is applied to the acrylic-modified organopolysiloxane, and the organopolysiloxane exudes from the acrylic-modified organopolysiloxane and bleeds out to the surface of the thermoplastic polyurethane elastomer composition or its molded product. In particular, in the case of a particulate copolymer in which the acrylic-modified organopolysiloxane forms a core-shell structure, the particles are cracked and the organopolysiloxane which is the main component of the core portion easily exudes. By exuding the organopolysiloxane and bleeding out to the surface of the thermoplastic polyurethane elastomer composition or its molded product, excellent slidability and antifouling property can be exhibited.

Examples of the acrylic gelation accelerator include an acrylic polymer obtained by homopolymerizing or copolymerizing an acrylic monomer.
Examples of the acrylic monomer include acrylic acid ester, methacrylic acid ester, acrylic acid, and methacrylic acid.
Examples of the acrylic acid ester include the acrylic acid ester exemplified above in the description of the acrylic-modified organopolysiloxane.
Examples of the methacrylic acid ester include methacrylic acrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and stearyl methacrylate; Alkoxyalkyl methacrylates such as butoxyethyl methacrylate; cyclohexyl methacrylates, phenyl methacrylates, benzyl methacrylates and the like can be mentioned. These are used alone or in combination of two or more.

The weight average molecular weight of the acrylic gelling accelerator is preferably ^{5.0 × 10 5 ~1.0 × 10 7} , more preferably ^{1.5 × 10 6 ~1.0 × 10 7} .
When the mass average molecular weight and the degree of polymerization of the acrylic gelation accelerator are within the above ranges, melt elasticity is more likely to be exhibited. As a result, an external force is more likely to be applied to the acrylic-modified organopolysiloxane, so that the organopolysiloxane is more likely to exude from the acrylic-modified organopolysiloxane, and the slidability and antifouling property are further improved.
In the present invention, the "mass average molecular weight" is a value measured by gel permeation chromatography and determined as polystyrene as a standard substance.

Commercially available products can be used as the acrylic gelation accelerator, for example, "Metabrene P-551A", "Metabren P-531A", "Metabren A-3000" manufactured by Mitsubishi Rayon Corporation; manufactured by Kaneka Corporation. "KANEACE PA-33", "KANEACE PA-40", "KANEACE PA-60"; "K400P", "K175" manufactured by Dow Chemical, etc. can be mentioned.

The content of the acrylic gelation accelerator is 0.1 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of TPU. When the content of the acrylic gelation accelerator is 0.1 parts by mass or more, melt elasticity is more likely to be exhibited. As a result, an external force is more likely to be applied to the acrylic-modified organopolysiloxane, so that the organopolysiloxane is more likely to exude from the acrylic-modified organopolysiloxane, and the slidability and antifouling property are further improved. On the other hand, when the content of the acrylic gelation accelerator is 10 parts by mass or less, good moldability can be maintained.

<Arbitrary ingredient>
The thermoplastic polyurethane elastomer composition may contain components (optional components) other than TPU, acrylic-modified organopolysiloxane, and acrylic gelation accelerator, if necessary.
Optional components include softeners such as process oils, fillers such as talc, carbon black and calcium carbonate, and various additives such as UV absorbers, antioxidants, processing stabilizers and colorants.

<Effect>
The above-mentioned TPU is a component that mainly contributes to extensibility and tensile strength, and acrylic-modified organopolysiloxane is a component that mainly contributes to slidability and antifouling property.
The thermoplastic polyurethane elastomer composition of the present invention also contains a specific amount of an acrylic gelation accelerator in combination with a TPU and a specific amount of acrylic-modified organopolysiloxane. Since melt elasticity is imparted by the action of an acrylic gelation accelerator, shearing force is likely to be applied to the kneaded product when each component is kneaded. As a result, the organopolysiloxane is exuded from the acrylic-modified organopolysiloxane, so that excellent slidability and antifouling property can be exhibited.
Therefore, when the thermoplastic polyurethane elastomer composition of the present invention is made into a molded product, or when a communication cable or an electric wire is coated, the slidability and antifouling property are maintained while maintaining the extensibility and tensile strength which are the characteristics of TPU. Excellent in sex.

By the way, as described above, it is difficult to exhibit the slidability and antifouling property which are the characteristics of the acrylic-modified organopolysiloxane by simply blending the acrylic-modified organopolysiloxane with the low-hardness TPU. This is because if the hardness of the TPU is low, it is difficult to apply a shearing force to the kneaded product during kneading, and it is difficult to apply an external force to the acrylic-modified organopolysiloxane, so that the organopolysiloxane does not sufficiently exude from the acrylic-modified organopolysiloxane. It is thought to be the cause.
However, in the thermoplastic polyurethane elastomer composition of the present invention, since the acrylic gelation accelerator is contained, the TPU is imparted with melt elasticity. Therefore, not only the high hardness TPU but also the low hardness TPU is sufficiently applied to the kneaded product at the time of kneading. As a result, the organopolysiloxane is sufficiently exuded from the acrylic-modified organopolysiloxane, and excellent slidability and antifouling property can be exhibited.

"Flexible material"
The flexible material obtained by the present invention comprises the above-mentioned thermoplastic polyurethane elastomer composition of the present invention. Therefore, the molded product obtained by molding the flexible material obtained by the present invention, or the communication cable or electric wire whose surface is coated with the flexible material obtained by the present invention has the extensibility and tensile strength which are the characteristics of TPU. While maintaining, it also has excellent slidability and antifouling properties.
The flexible materials obtained by the present invention include automobile parts, electronic / electrical equipment parts such as copiers (for example, toner seal materials, cleaning blades, etc.), film materials such as raincoats, water discharge hose materials, and molding of watch bands. Suitable for product materials, coating materials for communication cables and electric wires. The flexible material obtained by the present invention is particularly suitable as a coating material for a communication cable because it is excellent in slidability, antifouling property, extensibility and tensile strength.

"communication cable"
The surface of the communication cable obtained by the present invention is coated with the flexible material obtained by the present invention described above.
The configuration of the communication cable is not particularly limited as long as the outermost layer (sheath layer) is formed of the flexible material of the present invention. Examples thereof include a configuration coated with the flexible material of the present invention.

Since the surface of the communication cable obtained by the present invention is coated with the flexible material obtained by the present invention, the slidability and antifouling property are also maintained while maintaining the stretchability and tensile strength which are the characteristics of TPU. Excellent.
The communication cable obtained by the present invention is suitable as a communication cable used for devices such as robot arms, automatic assembly machines, and cranes of game machines, and is slidable even if the communication cable moves following the operation of these devices. The surface is not easily worn because it is excellent in. Moreover, since the communication cable of the present invention is excellent in elongation and tensile strength, it is difficult to cut even if the communication cable is pulled following the operation of these devices.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the description of these examples.
Example 9 is a reference example.

"Example 1"
100 parts by mass of thermoplastic polyurethane elastomer (manufactured by DIC Covestropolymer Co., Ltd., "T-8175N", Shore A hardness: 75A) and acrylic-modified organopolysiloxane (manufactured by Nissin Chemical Industry Co., Ltd., "Charine R-170S" , (A) / (b) = 7/3) 1 part by mass and 5 parts by mass of an acrylic gelling accelerator (“Metabrene P-551A” manufactured by Mitsubishi Rayon Co., Ltd.) are kneaded to make them thermoplastic. A polyurethane elastomer composition was obtained.
The obtained thermoplastic polyurethane elastomer composition was kneaded with 3.5 inch test rolls (2 rolls) at 170 ° C. for 7 minutes to obtain a roll sheet molded product. This was held by a mirror plate and preheated at 170 ° C. for 4 ^{minutes, and then pressurized at a pressure of 150 kg / cm 2} for 4 minutes to prepare a sheet-shaped test piece (120 mm × 120 mm) having a thickness of 1.0 mm. ..
The obtained test pieces were measured and evaluated by the methods shown below. The results are shown in Table 1.

<Measurement / evaluation>
(Measurement of hardness)
The Shore A hardness of the thermoplastic polyurethane elastomer was measured according to JIS K 6253-3: 2012.

(Evaluation of antifouling property)
A drop of water was dropped on the surface of the test piece, and the contact angle between the test piece and water was measured with a contact angle meter (“CA-X” manufactured by Kyowa Interface Science Co., Ltd.). The larger the value of the contact angle, the smaller the adhesive force and the better the antifouling property.

(Evaluation of slidability)
Using a friction tester (“Haydon 14D-ANL” manufactured by Shinto Kagaku Co., Ltd.), the dynamic friction coefficient of the test piece was measured under the conditions of a SUS steel ball having a diameter of 10 mm, a load of 50 g, and a tensile speed of 100 mm / min. The lower the coefficient of dynamic friction, the better the slidability.

(Tensile test)
In advance, the test piece was punched out with JIS K 6251 dumbbell No. 5 type, and a 25 mm marked line was marked.
Using a shopper type tensile tester, the test piece was pulled at a tensile speed of 200 mm / min and a temperature of 23 ° C., and 100% modulus was measured. Further, the maximum load required for the test piece to break was defined as the tensile strength (breaking strength). In addition, the distance between the marked lines when the test piece broke was measured, and the elongation rate was determined.

"Examples 2-9, Comparative Examples 1-5"
A thermoplastic polyurethane elastomer composition was prepared in the same manner as in Example 1 except that the composition was changed to the composition shown in Tables 1 and 2, test pieces were prepared, and various measurements and evaluations were performed. The results are shown in Tables 1 and 2.

As is clear from Table 1, from the thermoplastic polyurethane elastomer compositions obtained in each example, molded products having excellent antifouling property, slidability, extensibility and tensile strength were obtained.
On the other hand, in the case of Comparative Example 1 in which the acrylic-modified organopolysiloxane and the acrylic gelation accelerator were not used, a test piece could be prepared because a low hardness TPU was used, but antifouling property and slidability. Was inferior to.
In the case of Comparative Example 2 in which the acrylic gelation accelerator was not used, the antifouling property and the slidability were inferior.
In the case of Comparative Example 3 in which the acrylic-modified organopolysiloxane was not used, the antifouling property and the slidability were inferior.
In the case of Comparative Example 4 in which 150 parts by mass of acrylic-modified organopolysiloxane was used, the test piece could not be prepared because it could not withstand the stress during pressurization and mold release of the roll sheet molded product.
In the case of Comparative Example 5 in which 15 parts by mass of an acrylic gelation accelerator was used, the moldability was lowered and the test piece could not be prepared.

Claims (3)

It contains a thermoplastic polyurethane elastomer, an acrylic-modified organopolysiloxane, and an acrylic gelation accelerator.
The content of the acrylic-modified organopolysiloxane is 1 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic polyurethane elastomer, and the content of the acrylic gelation accelerator is 0.1 to 5 parts by mass. Oh it is,
The acrylic-modified organopolysiloxane, Ru particulate copolymer der forming a core-shell structure, the thermoplastic polyurethane elastomer composition. A molded product obtained by molding the thermoplastic polyurethane elastomer composition according to claim 1. The molded product according to claim 2, wherein the dynamic friction coefficient is 1.139 or less.