JP2013231152A - Thermoplastic elastomer composition, and electric wire and cable using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition capable of being produced through a simple process and excellent in recyclability, and to provide an electric wire and cable using the same.SOLUTION: A thermoplastic elastomer composition is configured to comprise: at least one elastomer selected from the group comprising a chloroprene rubber, a chlorosulfonated rubber, chlorinated polyethylene, an epichlorohydrin rubber, an acrylic rubber, a fluororubber, and vinyl chloride; and an ionic compound to be bonded to a main chain of the elastomer through an nitrogen atom and to be mutually crosslinked through a dipole-dipole interaction.

Description

  The present invention relates to a thermoplastic elastomer composition and an electric wire / cable using the same, and more specifically, for example, used as a resin composition coated as an electrical insulator on a conductor or conductor shielding layer of an electric wire / cable, The present invention relates to a thermoplastic elastomer composition into which a dipole-dipole interaction bridge of an ionic compound is introduced, and an electric wire / cable using the same.

  Recycling of used rubber materials is an important issue from the viewpoint of global environmental conservation and resource protection. The most difficult step in recycling the used rubber material is to break the crosslinks formed between the raw rubber molecules. Since the raw rubber molecular chain other than the crosslinked portion is also cut by the recycling treatment, the physical properties of the recycled rubber are generally inferior to those of the original raw rubber. Therefore, extensive research has been conducted on a crosslinking method capable of selectively cutting only the crosslinked portion.

  As one of methods for selectively cutting the crosslinks, a method using thermal dissociation of an ionic compound is known. A thermoplastic polymer having an ionic group is called an ionomer. The ionomer cross-linked portion of the ionomer has the property of repeating binding and dissociation due to temperature changes (see, for example, Non-Patent Document 1).

  Thermoplastic elastomers using these ionomers are not easily deteriorated in raw rubber characteristics even when the bonding and dissociation of crosslinking are repeated, and are excellent in recyclability. In a known example, a thermoplastic elastomer obtained by reacting a carboxylic acid-modified isoprene rubber with an aliphatic amine is known (for example, see Patent Document 1).

  In this elastomer, ammonium and carboxylate anion serve as thermoplastic crosslinking points. It has the characteristics of low cold flow and excellent recyclability.

  In the prior art, introduction of an ionic group into an elastomer is performed through a two-stage process. That is, (1) introduction of an acid group (carboxylic acid group, sulfonic acid group, sulfuric acid group, etc.), and (2) neutralization of an acid (addition of a metal or amine group).

Japanese Patent No. 3957395

Ionomer / ionic polymer materials (CMC Publishing)

  The first problem with the prior art is that the introduction of ionic groups requires two steps. From the viewpoint of industrial use, it is desired to produce a thermoplastic elastomer in a one-step process.

  The second problem with the prior art is that it is difficult to introduce ionic groups. There are technical problems in each of the introduction of the acid group in the first stage and the neutralization of the acid in the second stage.

  The problem with the introduction of acid groups in the first stage is that the acid groups cannot be grafted depending on the type of elastomer. In particular, when an acid group is introduced into an elastomer containing a halogen element such as chloroprene rubber or fluororubber, a cross-linking reaction between raw rubber molecules accompanying the elimination of the halogen element takes place preferentially. The graft reaction hardly proceeds.

  The problem with the neutralization of the acid in the second stage is that the neutralization reaction of the acid does not always proceed according to the stoichiometry. The following can be mentioned as the cause. A substance having a high melting point such as sodium hydroxide or zinc oxide added as an acid group is solid at a temperature (usually 200 ° C. or lower) at which it is kneaded with the elastomer, so that diffusion is slow and a neutralization reaction hardly occurs. Further, the neutralization reaction may be inhibited by reacting sodium hydroxide or zinc oxide with other additives of the elastomer.

  The present invention has been made in view of the above-described problems, and can provide a thermoplastic elastomer composition excellent in recyclability and an electric wire / cable using the thermoplastic elastomer composition which can be manufactured by a simple process. With the goal.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that an ionic compound having a predetermined structure is difficult to introduce an ionic group by a known method, that is, an chloroprene rubber, At least one kind of elastomer selected from the group consisting of chlorosulfonated rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, fluororubber and vinyl chloride is subjected to one step of a quantified and completely neutralized ionic group. A novel fact that it can be introduced (grafted) in the process was found, and the following present invention was completed.

[1] At least one elastomer selected from the group consisting of chloroprene rubber, chlorosulfonated rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, fluororubber and vinyl chloride, and the main chain of the elastomer via a nitrogen atom A thermoplastic elastomer composition comprising an ionic compound that is bonded and cross-linked together by dipole-dipole interaction.

[2] The ionic compound has a functional group containing a nitrogen atom that forms a covalent bond with the elastomer, and is bonded to the main chain of the elastomer through the nitrogen atom of the functional group, and the ionic compound. As ionic groups, carboxylic acid-metal group, sulfonic acid-metal group, sulfuric acid-metal group, carboxylic acid-ammonium group, sulfonic acid-ammonium group, sulfuric acid-ammonium group, carboxylic acid-hydradium group, sulfonic acid-hydradium The thermoplastic elastomer composition according to the above [1], which has at least one functional group selected from the group consisting of a group and a sulfate-hydradium group.

[3] The elastomer has a functional group containing a nitrogen atom covalently bonded to the ionic compound, and the ionic compound is bonded to the main chain of the elastomer through the nitrogen atom of the functional group of the elastomer. And the ionic compound has carboxylic acid-metal group, sulfonic acid-metal group, sulfuric acid-metal group, carboxylic acid-ammonium group, sulfonic acid-ammonium group, sulfuric acid-ammonium group, carboxylic acid- The thermoplastic elastomer composition according to the above [1], which has at least one functional group selected from the group consisting of a hydradium group, a sulfonic acid-hydradium group, and a sulfuric acid-hydradium group.

[4] The thermoplastic elastomer composition according to [2] or [3], wherein the functional group containing a nitrogen atom is an amino group.

[5] The thermoplastic elastomer composition according to any one of [1] to [4], wherein the dissociation temperature of the dipole-dipole interaction crosslinking of the ionic compound is in the range of 20 to 150 ° C.

[6] The thermoplastic elastomer composition according to any one of [1] to [5], wherein the ionic compound is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the elastomer.

[7] The thermoplastic elastomer composition according to any one of [1] to [6], wherein the ionic compound is a polyamine compound.

[8] An electric wire / cable having an insulator and / or sheath formed using the thermoplastic elastomer composition according to any one of [1] to [7].

  The present invention can be produced by a simple process, and can provide a thermoplastic elastomer composition excellent in recyclability and an electric wire / cable using the same.

3 is a graph showing the results of IR measurement in Example 1. It is a graph which shows the relationship (temperature dependence of storage elastic modulus) between the storage elastic modulus and temperature in Example 1 and Comparative Example 1.

[Summary of embodiment]
The thermoplastic elastomer composition of the present embodiment is an elastomer composition containing an elastomer and an ionic compound bonded to the main chain of the elastomer. Chloroprene rubber, chlorosulfonated rubber, chlorinated polyethylene, epichlorohydrin rubber, At least one elastomer selected from the group consisting of acrylic rubber, fluororubber, and vinyl chloride, and an ionic property that is bonded to the main chain of the elastomer through a nitrogen atom and is crosslinked to each other by dipole-dipole interaction And a compound.

  Moreover, the electric wire and cable of this Embodiment have an insulator and / or a sheath formed using the above-mentioned thermoplastic elastomer composition.

[Thermoplastic elastomer composition according to the embodiment]
As described above, the thermoplastic elastomer composition according to the embodiment of the present invention is at least selected from the group consisting of chloroprene rubber, chlorosulfonated rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, fluororubber and vinyl chloride. A thermoplastic elastomer composition comprising one type of elastomer and an ionic compound that is bonded to the main chain of the elastomer through a nitrogen atom and is crosslinked to each other by dipole-dipole interaction. Hereinafter, each component will be described.

(Elastomer)
The type of elastomer used in the present embodiment is not particularly limited as long as the main chain of the elastomer and an ionic compound described below can be bonded via a nitrogen atom. Specifically, chloroprene rubber, chlorosulfonated It may contain at least one selected from the group consisting of rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, fluororubber and vinyl chloride. In addition to these, a known polymer may be contained, and there is no particular limitation on the form of its inclusion. Moreover, there is no restriction | limiting in particular if the content rate is also in the range which shows thermoplasticity. The weight average molecular weight of the elastomer may be appropriately determined based on the viscosity of the elastomer in the dissociated state of the dipole-dipole interaction crosslinking. When the fluidity of the elastomer is required, the molecular weight is preferably about 1,000 to 100,000. When the strength of the elastomer is required, it is preferably 100,000 or more, more preferably about 200,000 to 1,000,000.

  The ionic compound and the main chain of the elastomer are bonded via a nitrogen atom. Before the ionic compound and the main chain of the elastomer form a bond, the structure (functional group) containing a nitrogen atom may exist on the elastomer side or may exist on the ionic compound side.

  As a case where a structure containing a nitrogen atom is present on the elastomer side, for example, the elastomer has a functional group containing a nitrogen atom that forms a bond (for example, a covalent bond) with the ionic compound, The case where it couple | bonds with the principal chain of an elastomer through the nitrogen atom of the functional group of an elastomer can be mentioned. Specifically, when the elastomer has an amino group as a structure (functional group) containing a nitrogen atom in its chemical structure, the amine moiety and the ionic compound form some bond (for example, a covalent bond). As a result of the reaction, the elastomer and the ionic compound form a bond (for example, a covalent bond) through the nitrogen atom.

  On the other hand, the case where a structure containing a nitrogen atom exists on the ionic compound side will be described later.

  If an elastomer having a structure containing a nitrogen atom can be easily obtained, it may be utilized, but it is often not commercially available. In such a case, the coupling | bonding (for example, covalent bond) of an elastomer and an ionic compound can be achieved by selecting the ionic compound mentioned later suitably. The elastomer in the present invention, that is, chloroprene rubber, chlorosulfonated rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, fluororubber, and vinyl chloride can be easily subjected to addition reaction with an amino group.

(Ionic compounds)
The ionic compound used in the present embodiment only needs to be capable of bonding (for example, covalent bonding) to the main chain of the elastomer via a nitrogen atom. As described above, before the bond between the ionic compound and the main chain of the elastomer forms a bond, the structure containing a nitrogen atom may exist on the elastomer side or may exist on the ionic compound side.

  When a structure (functional group) containing a nitrogen atom exists on the ionic compound side, for example, when the ionic compound has an amino group as a structure (functional group) containing a nitrogen atom in its chemical structure Is a reaction in which the amino group and the elastomer form some bond (for example, a covalent bond), and the elastomer and the ionic compound form a bond (for example, a covalent bond) through a nitrogen atom. In particular, it preferably has an amino group having a primary amine structure or a secondary amine structure. The amino group of the primary amine structure or the secondary amine structure easily undergoes an addition reaction with the main chain of the elastomer of the present embodiment.

In addition to the functional group bonded to the elastomer, in the ionic compound, as an ionic group, a carboxylic acid-metal group, a sulfonic acid-metal group, a sulfuric acid-metal group, a carboxylic acid-ammonium group, a sulfonic acid-ammonium group, sulfuric acid It preferably has at least one functional group selected from the group consisting of an ammonium group, a carboxylic acid-hydradium group, a sulfonic acid-hydradium group, and a sulfuric acid-hydradium group. As shown in the following formula (1), a molecule containing these ionic groups includes a cation X (for example, metal cation, NH ₄ ^{+ and the} like) and an anion Y (for example, COO ⁻ , SO ₃ ²⁻ , SO ₄ ^2- etc.), an electrostatic interaction between charges, that is, an ionic bond is formed. In addition, since this molecule has polarity, the molecule exhibits dipole-dipole interaction (this is a cross-linking point of the elastomer).

  The binding energy of ionic bonds is 40 to 400 kJ / mol, and the dissociation temperature is much higher than room temperature. Therefore, the elastomer crosslinked by ionic bond does not show thermoplasticity. In contrast, the energy of the dipole-dipole interaction is 0.5-15 kJ / mol. Since the energy of the dipole-dipole interaction is slightly larger than the thermal energy of the molecule at room temperature, the elastomer is in a crosslinked state near room temperature due to the dipole-dipole interaction. As the temperature is raised, the thermal energy of the molecule exceeds the energy of the dipole-dipole interaction at a certain temperature, and the bridge dissociates. Near that temperature, the elastomer begins to flow. That is, the elastomer of the present invention exhibits thermoplasticity due to cross-linking of dipole-dipole interactions, and is excellent in mechanical properties when cross-linked in a low-temperature region, and in a state where cross-linking in a high-temperature region is dissociated. It has a secondary effect of showing fluidity.

  The energy of the dipole-dipole interaction depends on the chemical structure of the ionic compound and the number of bonds. In the above formula (1), the greater the polarization of X and Y, the greater the energy of the dipole-dipole interaction. Moreover, the sum of energy becomes larger when a plurality of bonds are formed than with one bond. Although rigorous discussion is difficult, in experiments in the present invention, strong crosslinks are formed in ionic compounds having either a carboxylic acid-metal group or a sulfonic acid-metal group and a high valence of metal ions. It was confirmed that the mechanical properties of the elastomer were improved.

A carboxylic acid-metal group means an ionic group represented by COO ⁻ —M ⁺ (M ⁺ is a metal cation). The valence of the metal cation is not particularly limited, and the number of COO ^- groups that are bonded varies depending on the valence. Examples of the compound having a carboxylic acid-metal group include sodium aspartate, magnesium aspartate, potassium aspartate, sodium N-methylglycine, sodium N-benzoylglycine, sodium glutamate, selenomethionine, and L-tyrosine disodium. Can do.

A sulfonic acid-metal group means SO ₃ ^2- -M ⁺ ₂ and a sulfuric acid-metal group means an ionic group represented by SO ₄ ^2- -M ⁺ ₂ . No particular limitation is imposed on the valence of the metal cation, also changes the number of SO ₃ ^2-group and SO ₄ ^2-group attached depending on the valence. Examples of the compound having a sulfonic acid-metal group or a sulfuric acid-metal group include 3-amino-1,5-naphthalenedisulfonic acid disodium salt, 3-amino-2,7-naphthalenedisulfonic acid-sodium salt, and diphenylamine-4-sulfonic acid. Barium, sodium 4-amino-1,5-naphthalenedisulfonate, sodium 2-amino-1-naphthalenesulfonate, sodium 7-amino-2-naphthalenesulfonate, sodium diphenylamine-4-sulfonate, N-cyclohexylsulfamic acid Sodium, magnesium 8-anilino-1-naphthalenesulfonate, dipotassium indigodisulfonate, tetrapotassium indigotetrasulfonate, potassium indigotrisulfonate, 7-amino-1, monopotassium 3-naphthalenedisulfonate object Diphenylamine-4-barium-sulfonic acid, and the like.

The carboxylic acid-ammonium group means an ionic group represented by COO ⁻ —NH ₄ ⁺ and the carboxylic acid-hydradium group means COO ⁻ —NH ₃ ⁺ NH ₂ . Examples of the compound having a carboxylic acid-ammonium group or a carboxylic acid-hydradium group include ammonium formate, ammonium acetate, ammonium adipate, ammonium benzoate, diammonium hydrogen citrate, ammonium succinate, diammonium oxalate-hydrate, Examples include ammonium sebacate, diammonium phthalate, diammonium 1,10-decanedicarboxylate, diammonium 2-hydroxy-1,2,3-propanetricarboxylic acid, hydradium acetate, dihydradium adipate, and the like.

The sulfonic acid-ammonium group is SO ₃ ²⁻ (NH ₄ ⁺ ) ₂ , the sulfonic acid-hydradium group is SO ₃ ²⁻ (NH ₃ ⁺ NH ₂ ) ₂ , and the sulfuric acid-ammonium group is SO 2 _{The 4} ² --(NH ₄ ⁺ ) ₂ and sulfate-hydradium groups mean an ionic group represented by SO ₄ ^2- (NH ₃ ⁺ NH ₂ ) ₂ . Examples of the compound having an ionic group include ammonium heptadecafluoro-1-octanesulfonate, ammonium 8-anilino-1-naphthalenesulfonate, and hydradium sulfate.

  Since the above compound group has an amine group in its structure, it can be easily added to the elastomer in the present invention by a one-step reaction. Further, the above compound group has a structure that is already neutralized 100%. Therefore, it is possible to avoid the problem of the prior art that the mechanical properties of the thermoplastic elastomer deteriorate due to insufficient neutralization.

  Among the above compound groups, it was confirmed that a compound containing a metal has a particularly large improvement in the mechanical properties of the elastomer. A compound containing a metal group has a higher degree of polarization in the molecule than a compound containing an ammonium group or a hydradium group. As a result, it is considered that the energy of the dipole-dipole interaction is increased, a strong crosslink is formed in the thermoplastic elastomer, and the mechanical properties are improved.

  The amount of the ionic compound introduced into the elastomer may be appropriately determined, but is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the elastomer. If it is less than 0.1 part by mass, the contribution of dipole-dipole interaction is too small, and sufficient mechanical strength may not be obtained. On the other hand, when it exceeds 50 parts by mass, the crosslink density is too high and rubber elasticity may be lost.

  When there are two or more nitrogen atoms bonded to the elastomer in the structure of the ionic compound, for example, in the case of a polyamine compound having a plurality of amino groups, the elastomers may be covalently crosslinked (amino crosslinked). . That is, in addition to the dipole-dipole interaction bridge, a covalent bond bridge is also formed. This covalent cross-linking is much stronger than the dipole-dipole interaction cross-linking and greatly improves the mechanical properties of the thermoplastic elastomer. However, since covalent crosslinking is not dissociated by heat, if the amount introduced is too large, thermoplasticity may be impaired. The amount of covalent bond introduced may be determined in consideration of the balance between the desired mechanical properties and thermoplasticity.

  The production apparatus for reacting the thermoplastic elastomer composition of the present invention is not particularly limited, and can be produced by mixing with a pressure kneader, a Banbury mixer, a Brabender, a single screw extruder, a twin screw extruder, or the like. . The temperature at which the elastomer reacts with the ionic compound may be appropriately selected, and can be, for example, 70 to 200 ° C. If it is less than 70 ° C., the graft reaction may not proceed. When the temperature exceeds 200 ° C., particularly in the case of an elastomer containing a halogen, the dehalogenation reaction becomes remarkable, and the elastomer may be deteriorated. Further, at the reaction temperature, it is preferable that the ionic compound is in a molten state in order for the elastomer and the ionic compound to react efficiently. In consideration of the above, it is more preferable to carry out between 80-160 degreeC.

  The thermoplastic elastomer composition of the present invention can contain substances other than those described above as long as the object of the present invention is not impaired. For example, polymers other than thermoplastics, reinforcing agents, anti-aging agents, antioxidants, pigments, plasticizers, ultraviolet absorbers, cross-linking agents, cross-linking aids and the like can be appropriately contained.

  In the thermoplastic elastomer composition of the present invention, other crosslinks may be appropriately introduced in addition to dipole-dipole interaction crosslinks. For example, a crosslinking agent that forms a permanent crosslink (covalent bond or ionic bond) that does not have thermoplasticity can be mixed in the elastomer composition. In that case, since the dipole-dipole interaction crosslinks are formed first, and no permanent crosslinks are formed, the elastomer exhibits thermoplasticity. Thereafter, if a permanent crosslink is formed by some treatment, the elastomer loses thermoplasticity and at the same time the mechanical properties are greatly improved.

  The electric wire / cable of the present invention has an insulator and / or a sheath formed by using the above-mentioned thermoplastic elastomer composition. There is no restriction | limiting in particular as a formation method of an insulator and / or a sheath, The method currently used widely, such as extrusion, can be used. Since the electric wire / cable of the present invention is formed using the above-mentioned thermoplastic elastomer composition, it is inexpensive and has excellent insulating properties and recyclability.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these specific examples. In addition, the measurement of the chemical structure and each physical property in each Example was implemented as follows.

(1) Chemical structure The introduction of the ionic compound into the elastomer was confirmed by IR measurement. The obtained thermoplastic elastomer was subjected to acetone extraction (reflux temperature: 70 ° C., 24 hours) to remove unreacted ionic compounds and additives remaining in the thermoplastic elastomer. The extracted thermoplastic elastomer was used as a measurement sample. For the IR measurement, an FT-IR apparatus (manufactured by JASCO, trade name: FT / IR-615) was used.

(2) Dissociation temperature of the dipole-dipole interaction crosslink The dissociation temperature of the dipole-dipole interaction crosslink was evaluated from the decrease in the storage elastic modulus of the thermoplastic elastomer. For the measurement of storage elastic modulus (dynamic viscoelasticity measurement), a measuring device (product name: DVA-200, manufactured by IT Measurement Control Co., Ltd.) was used. The thermoplastic elastomer was press-molded at 100 ° C. for 5 minutes to produce a 2 mm thick sheet. This sheet was cut into a test piece having a length of 30 mm and a width of 5 mm to obtain a measurement sample. Measurement was carried out from room temperature to 200 ° C. at a rate of temperature increase of 10 ° C./min and a frequency of 10 Hz.

  The storage elastic modulus of an elastomer that does not form crosslinks decreases monotonically with increasing temperature. On the other hand, the storage elastic modulus of the thermoplastic elastomer cross-linked by the dipole-dipole interaction shows a substantially constant value before the dissociation temperature of the cross-linking, and rapidly decreases when the cross-linking dissociation temperature is exceeded. Therefore, the following two items were confirmed in the measurement of dynamic viscoelasticity. The first is that the storage elastic modulus shows a constant value before the crosslinking dissociation temperature. The second point is that the storage elastic modulus lowering point (that is, the dissociation temperature of the dipole-dipole interaction bridge of the ionic compound) is between 20 ° C and 150 ° C. The result of the dynamic viscoelastic behavior was combined with the result of (7) recyclability described later, and used as a criterion for determining whether or not it was a thermoplastic elastomer.

(3) Mooney viscosity The Mooney viscosity of the thermoplastic elastomer was measured according to JISK6300-1 using a Mooney viscometer (trade name: VR-1130, manufactured by Ueshima Seisakusho Co., Ltd.). Preheating was performed at a temperature of 100 ° C. for 1 minute, and the Mooney viscosity after 4 minutes of heating was used as a measured value.

(4) Tensile properties A thermoplastic elastomer was press-molded at 100 DC for 5 minutes to produce a 2 mm thick sheet. This sheet was punched with a No. 3 dumbbell and used as a test sample. A tensile test was performed according to JISK6251. The tensile speed was 500 mm / min, and the test temperature was 25 ° C. (room temperature). 100% modulus (100% M) [MPa], 300% modulus (300% M) [MPa], breaking strength (Tb) [MPa], and breaking elongation (Eb) [%] were measured.

(5) JIS-A hardness A thermoplastic elastomer was press-molded at 100 ° C. for 5 minutes to produce a sheet sample having a thickness of 2 cm × length 15 cm × width 15 cm. According to JISK6253, JIS-A hardness was measured using a durometer (manufactured by Shimadzu Corporation).

(6) Compression set A thermoplastic elastomer was molded into a cylindrical shape (diameter 29 mm, thickness 12.5 mm) to obtain a test piece. According to JISK6262, the test piece was compressed by 25% and left at 40 ° C. for 24 hours. The compression set after standing was measured.

(7) Recyclability The thermoplastic elastomer was hot-pressed at 100 ° C. for 5 minutes to produce a 2 mm thick sheet. This sheet was finely cut and press-molded again, and the recyclability was evaluated by the number of times that a seamless sheet could be produced. What was produced 10 times or more was made into (circle), and less than 10 times was made into x.

Example 1
As an elastomer, 100 g of chloroprene rubber (manufactured by Showa Denko KK, trade name: Shoprene W) and L-sodium aspartate-hydrate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 173.10 g / mol) as an ionic compound. 2.2 g and 1 g of MgO (Kyowa Chemical Industry Co., Ltd., Kyowa Mag) as an additive were added and stirred with heating at 120 ° C. for 15 minutes in a kneader to prepare a thermoplastic elastomer.

The resulting thermoplastic elastomer was extracted with acetone to remove unreacted sodium L-aspartate-hydrate. Was subjected to IR measurement of a sample of the remaining thermoplastic elastomer after extraction, as shown in FIG. 1, a weak peak secondary amine structure in the vicinity of 1600 cm ^-1, a peak of carbonyl group near 1700 cm ^-1 was confirmed . This result shows that sodium L-aspartate-hydrate is grafted to chloroprene. Crosslinking of the dipole-dipole interaction of the resulting thermoplastic elastomer is shown below.

  When the dynamic viscoelasticity of the thermoplastic elastomer was measured, as shown in FIG. 2, the storage elastic modulus showed a constant value from room temperature to around 50 ° C., and the decrease became remarkable from around 50 ° C. It is considered that the bridge of dipole-dipole interaction is dissociated around this temperature. The other evaluation results are shown in Table 1.

(Example 2)
A thermoplastic elastomer was produced in the same manner as in Example 1 except that the ionic compound was changed to magnesium aspartate tetrahydrate (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 360.56 g / mol). Was subjected to IR measurement of a sample of a thermoplastic elastomer remaining after acetone extraction, weak peaks of secondary amine structure in the vicinity of 1600 cm ^-1, a peak of carbonyl group near 1700 cm ^-1 was confirmed. This result indicates that magnesium aspartate tetrahydrate is grafted to chloroprene. Crosslinking of the dipole-dipole interaction of the resulting thermoplastic elastomer is shown below.

  When the dynamic viscoelasticity of the thermoplastic elastomer was measured, the storage elastic modulus showed a constant value from room temperature to around 50 ° C., and the decrease became remarkable from around 50 ° C. It is considered that the bridge of dipole-dipole interaction is dissociated around this temperature. The other evaluation results are shown in Table 1.

(Example 3)
A thermoplastic elastomer was produced in the same manner as in Example 1 except that the ionic compound was changed to sodium 3-amino-2,7-naphthalenedisulfonate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 325.29 g / mol). did. Was subjected to IR measurement of a sample of a thermoplastic elastomer remaining after acetone extraction, weak peaks of secondary amine structure in the vicinity of 1600 cm ^-1, a peak of sulfone groups in the vicinity of 1151cm ^-1 was confirmed. This result indicates that sodium 3-amino-2,7-naphthalenedisulfonate is grafted to chloroprene. Crosslinking of the dipole-dipole interaction of the resulting thermoplastic elastomer is shown below.

  When the dynamic viscoelasticity of the thermoplastic elastomer was measured, the storage elastic modulus showed a constant value from room temperature to around 50 ° C., and the decrease became remarkable from around 50 ° C. It is considered that the bridge of dipole-dipole interaction is dissociated around this temperature. The other evaluation results are shown in Table 1.

Example 4
A thermoplastic elastomer was produced in the same manner as in Example 1 except that the ionic compound was changed to 3-cyclohexylamino-2-hydroxypropanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 259.3 g / mol). . Was subjected to IR measurement of a sample of a thermoplastic elastomer remaining after acetone extraction, weak peaks of secondary amine structure in the vicinity of 1600 cm ^-1, a peak of sulfone groups in the vicinity of 1151cm ^-1 was confirmed. This result indicates that 3-cyclohexylamino-2-hydroxypropanesulfonic acid is grafted to chloroprene. Crosslinking of the dipole-dipole interaction of the resulting thermoplastic elastomer is shown below.

  When the dynamic viscoelasticity of the thermoplastic elastomer was measured, the storage elastic modulus showed a constant value from room temperature to around 55 ° C., and the decrease became remarkable from around 55 ° C. It is considered that the bridge of dipole-dipole interaction is dissociated around this temperature. The other evaluation results are shown in Table 1.

(Examples 5 to 8)
A thermoplastic elastomer was produced in the same manner as in Examples 1 to 4 except that the elastomer was changed to fluororubber (manufactured by DuPont Elastomer Co., Ltd., trade name: Viton B). In each Example, it was confirmed by IR measurement that the ionic compound was grafted on the fluororubber. The evaluation results are shown in Table 1.

Example 9
In Example 2, Example 2 except that the compounding amount of magnesium aspartate tetrahydrate (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 360.56 g / mol) as an ionic compound was changed to 40 parts by mass. Similarly, a thermoplastic elastomer was produced. The evaluation results are shown in Table 1.

(Comparative Example 1)
A thermoplastic elastomer was produced in the same manner as in Example 1 except that no ionic compound was added. In the IR measurement, only the peak derived from chloroprene was confirmed. When the dynamic viscoelasticity was measured, as shown in FIG. 2, the storage elastic modulus tended to monotonously decrease with increasing temperature. The evaluation results are shown in Table 2.

(Comparative Example 2)
Japanese Patent No. 3807907 describes the addition of maleic anhydride to isoprene rubber. Furthermore, Japanese Patent No. 3957395 (Patent Document 1) describes a method for obtaining a thermoplastic elastomer having a carboxylic acid-ammonium group as a crosslinking point by adding stearylamine to a carboxylic acid-modified liquid isoprene rubber. According to these known examples, Comparative Example 2 attempted to modify chloroprene rubber with carboxylic acid. 100 g of chloroprene rubber (manufactured by Showa Denko KK, trade name: Showprene W), 1.3 g of maleic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 98.06 g / mol), MgO (Kyowa Chemical Industry Co., Ltd.) as an additive (Product name: Kyowa Mug) was added, and the mixture was stirred with heating at 150 ° C. for 30 minutes in a kneader to graft maleic anhydride. Unreacted maleic anhydride was removed by extracting the chloroprene rubber after the reaction with acetone. When IR measurement was performed on a sample of chloroprene rubber remaining after extraction, no peak derived from maleic anhydride was confirmed. This result indicates that maleic anhydride is not grafted onto chloroprene. It can be seen that the chloroprene rubber cannot be modified with carboxylic acid by the method of Comparative Example 2.

(Comparative Example 3)
In Comparative Example 2, stearylamine (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 269.51 g / mol) was added to chloroprene rubber (including MgO and maleic anhydride) heated and stirred at 150 ° C. for 60 minutes in a kneader. In addition, the mixture was heated and stirred at 150 ° C. for 30 minutes with a kneader to add stearylamine to maleic anhydride. The resulting chloroprene rubber was extracted with acetone to remove unreacted maleic anhydride and stearylamine. When the IR measurement was performed on the sample of the thermoplastic elastomer remaining after the extraction, no peak derived from maleic anhydride was confirmed, and a weak peak of a secondary amine structure was confirmed in the vicinity of 1610 cm ⁻¹ . This result shows that stearylamine is grafted on chloroprene and does not react with maleic anhydride.

  When the dynamic viscoelasticity was measured, the storage elastic modulus tended to monotonously decrease with increasing temperature. The other evaluation results are shown in Table 2. The mechanical properties (tensile properties, compression set, A hardness) and recyclability were the same as in Comparative Example 1. From the results of Comparative Example 2 and Comparative Example 3, it can be seen that in the known method, introduction of acid groups into the chloroprene rubber does not proceed, so that a thermoplastic elastomer cannot be produced.

(Comparative Example 4)
Example 1 except that the ionic compound was changed to dodecylamine having a primary amine structure (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight: 185.3 g / mol), which is a compound that does not show dipole-dipole interaction. Similarly, a thermoplastic elastomer was produced. When the IR measurement was performed on the sample of the thermoplastic elastomer remaining after the extraction with acetone, a weak peak of a secondary amine structure was confirmed in the vicinity of 1610 cm ⁻¹ . This result indicates that dodecylamine is grafted onto chloroprene. When the dynamic viscoelasticity was measured, the storage elastic modulus tended to monotonously decrease with increasing temperature. The other evaluation results are shown in Table 2. The mechanical properties (tensile properties, compression set, A hardness) and recyclability are the same results as in Comparative Example 1, and it can be seen that the method of Comparative Example 4 cannot produce a thermoplastic elastomer.

(Comparative Examples 5 to 8)
A thermoplastic elastomer was produced in the same manner as in Comparative Examples 1 to 4, except that the elastomer was changed to fluororubber (manufactured by DuPont Elastomer Co., Ltd., trade name: Viton B). The evaluation results are shown in Table 2. It turns out that a thermoplastic elastomer cannot be manufactured by the method of Comparative Examples 5-8 for the same reason as Comparative Examples 1-4.

Claims (8)

At least one elastomer selected from the group consisting of chloroprene rubber, chlorosulfonated rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, fluororubber and vinyl chloride;
A thermoplastic elastomer composition comprising: an ionic compound bonded to a main chain of the elastomer through a nitrogen atom and crosslinked to each other by dipole-dipole interaction.   The ionic compound has a functional group containing a nitrogen atom that forms a covalent bond with the elastomer, and is bonded to the main chain of the elastomer through the nitrogen atom of the functional group, and the ionic compound is an ion As groups, carboxylic acid-metal group, sulfonic acid-metal group, sulfuric acid-metal group, carboxylic acid-ammonium group, sulfonic acid-ammonium group, sulfuric acid-ammonium group, carboxylic acid-hydradium group, sulfonic acid-hydradium group, and The thermoplastic elastomer composition according to claim 1, which has at least one functional group selected from the group consisting of sulfuric acid-hydradium groups.   The elastomer has a functional group containing a nitrogen atom covalently bonded to the ionic compound, the ionic compound is bonded to the main chain of the elastomer through the nitrogen atom of the functional group of the elastomer; and The ionic compound has, as an ionic group, a carboxylic acid-metal group, a sulfonic acid-metal group, a sulfuric acid-metal group, a carboxylic acid-ammonium group, a sulfonic acid-ammonium group, a sulfuric acid-ammonium group, a carboxylic acid-hydradium group, The thermoplastic elastomer composition according to claim 1, which has at least one functional group selected from the group consisting of a sulfonic acid-hydradium group and a sulfuric acid-hydradium group.   The thermoplastic elastomer composition according to claim 2 or 3, wherein the functional group containing a nitrogen atom is an amino group.   The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein a dissociation temperature of crosslinking of dipole-dipole interaction of the ionic compound is in a range of 20 to 150 ° C.   The thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the ionic compound is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the elastomer.   The thermoplastic elastomer composition according to any one of claims 1 to 6, wherein the ionic compound is a polyamine compound.   The electric wire and cable which have an insulator and / or a sheath formed using the thermoplastic-elastomer composition in any one of Claims 1-7.

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