JP2617282B2 - Thermoplastic elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition obtained by mixing a thermoplastic polyurethane elastomer and an aliphatic polyester.

[0002]

2. Description of the Related Art At present, thermoplastic elastomers (hereinafter TP)
E) is gaining attention as a new form of rubber. TPE exhibits rubber elasticity without the need for vulcanization operations required for conventional natural and synthetic rubbers, simplifying the production process, and being easy to mold because it is plasticized at high temperatures. It has the advantage that scrap can be reused, and has recently been used widely in automotive parts, hoses, tubes and the like.

[0003] The molecular structure of TPE is characterized by cross-linking that does not rely on strong chemical bonding, that is, a system in which some kind of intermolecular constraining is effective only at around room temperature, and is composed of a soft segment and a hard segment. Aggregation is a typical structure of TPE. The soft segment and the hard segment have different chemical structures from each other. In the hybrid composition of the two, the homogenous parts agglomerate, and the heterogeneous parts form a micro-unbalanced structure in which the phases are separated from each other. The agglutinated portion shows a binding effect between the molecules.

[0004] Typical TPEs include, for example, styrene, olefin, urethane, ester, and amide.

For example, in a urethane-based TPE, a polymer chain composed of a diisocyanate and a short-chain glycol is a hard segment, and a polymer chain composed of a diisocyanate and a long-chain polyol is a soft segment. These urethane-based TPEs have attracted attention as high-performance TPEs because of their excellent wear resistance, bending fatigue resistance, mechanical strength, and oil resistance. However, they are inferior in chemical resistance, weather resistance, thermal stability during molding and the like. Japanese Patent Application Laid-Open No. 50-79559 proposes an elastomer composition comprising a thermoplastic polyurethane elastomer mixed with a polyester block copolymer. In this mixed elastomer, water resistance and moldability were improved, but weather resistance and chemical resistance were not improved.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide wear resistance, flex fatigue resistance, mechanical strength, chemical resistance, weather resistance, and molding resistance. An object of the present invention is to provide a urethane-based thermoplastic elastomer composition having excellent properties.

[0007]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present invention has been reached. In other words, in the case of urethane-based thermoplastic elastomers, the performance of urethane-based TPE is not impaired by blending a specific aliphatic polyester elastomer with the urethane-based elastomer.
It has been found that chemical resistance, weather resistance, and moldability are improved.

That is, the present invention relates to (A) a thermoplastic polyurethane elastomer containing 20 to 80% by weight; (B) an aliphatic dicarboxylic acid, an aliphatic diol represented by the following formula [I], and a general formula: 80 to 20% by weight of an aliphatic polyester containing at least one of a dihydroxy compound represented by the following formula [II] and a monohydroxy compound represented by the following formula [III]: The above object is achieved.

HOOC- (CH ₂ ) n-COOH [I] (wherein, n represents an integer of 0-10)

[0010]

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(Wherein, R ¹ and R ^{2 each} independently represent an alkylene group, p is 3 or 4, and q and r each independently represent 0 or an integer of 1 or more.)

[0012]

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(Wherein, R ³ represents an alkylene group, l is 2 or 3, and m represents an integer of 0 or 1 or more.) [Aliphatic polyester] In the above aliphatic dicarboxylic acid, the number of carbon atoms is If the dicarboxylic acid is used in excess of 10, the physical properties of the molded article obtained from the aliphatic polyester will be reduced.
Examples of the dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid,
Sebacic acid is preferably used.

The aliphatic diols include glycols and polyalkylene oxides. Examples of the glycol include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, cyclopentane-1,2-diol, cyclohexane-1,2- Diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, etc., which may be used alone or in combination of two or more .

The polyalkylene oxide includes, for example, polyethylene oxide, polypropylene oxide, polytetramethylene oxide, polyhexamethylene oxide and the like. These may be used alone or in combination of two or more. Good. If the number average molecular weight of the polyalkylene oxide is too small, the ability to impart flexibility to the resulting aliphatic polyester is reduced, and if it is too large, physical properties such as thermal stability of the resulting aliphatic polyester are reduced. It is preferably 20,000, more preferably 500 to 5,000.

The dihydroxy compound represented by the above formula [II] is a low-molecular compound exhibiting liquid crystallinity, and the alkylene groups R ¹ and R ² are preferably an ethylene group or a propylene group.
And r are preferably 0 or 1, and represented by the following formula [A]:
4 ''-dihydroxy-p-terphenyl, 4,4 '''-dihydroxy-p-quarterphenyl represented by the following formula [B] and 4,4'''-represented by the following formula [C] Di (2-hydroxyethoxy) -p-quarterphenyl and the like are preferably used.

[0017]

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The transition temperature from the crystalline state of 4,4 ''-dihydroxy-p-terphenyl [A] to the liquid crystal state is 260 ° C.
And 4,4 '''-dihydroxy-p-quarterphenyl [B]
At 336 ℃, 4,4 '''-di (2-hydroxyethoxy) -p
The temperature of -quarterphenyl [C] is 403 ° C. still,
The liquid crystal state refers to a state in which the compound is in a molten state and molecules are in an aligned state. Each of the above dihydroxy compounds [II] may be used alone or in combination.

Liquid crystal molecules generally have high crystallinity, and as described above, 4,4 "-dihydroxy-p-terphenyl [A] and 4,4 '"-dihydroxy-p-quarterphenyl [B]. And 4,4 '''-di (2-hydroxyethoxy) -p-quarterphenyl [C] have a high transition point from the crystal to the liquid crystal state, so that these dihydroxy compounds [II] are contained in the polymer chain. When incorporated, the polymer exhibits unique properties.

That is, since the dihydroxy compound [II] exhibits crystallinity and its transition point is high, even when the amount of the dihydroxy compound [II] is small, a strong and heat-resistant physical crosslink is formed. As a result, it is presumed that a thermoplastic elastomer having high heat resistance can be obtained without impairing the flexibility derived from the soft segment.

The monohydroxy compound represented by the above formula [III] is a rigid low-molecular compound having a paraphenylene skeleton, and the melting point of these compounds is extremely high, reflecting the characteristic molecular structure. Furthermore, the paraphenylene skeleton is known to be effective as a mesogen for low-molecular liquid crystal compounds, which means that the skeleton has a strong cohesive force not only in a solid state but also in a high temperature state (molten state). It shows. Therefore, when the above-mentioned monohydroxy compound [III] is incorporated into the terminal of the polymer, a very strong and highly heat-resistant physical crosslinking is produced, and a thermoplastic elastomer having excellent heat resistance is produced.

In the monohydroxy compound represented by the formula [III], R ³ is preferably an ethylene group or a propylene group, and m is preferably 0 or 1. Examples of the monohydroxy compound include 4-hydroxy-p-terphenyl, 4-hydroxy-p-quarterphenyl, and 4- (2
-Hydroxyethoxy) -p-terphenyl, 4- (2-hydroxyethoxy) -p-quarterphenyl and the like. The monohydroxy compound [III] may be used alone or in combination.

Polysilicon having two hydroxyl groups in an aliphatic polyester comprising at least one of the above-mentioned aliphatic dicarboxylic acid [I], aliphatic diol and dihydroxy compound [II] and monohydroxy compound [III] Alternatively, lactone or aromatic hydroxycarboxylic acid may be contained as a component.

The above-mentioned polysilicone has two hydroxyl groups, and is preferably a silicone having two hydroxyl groups at the molecular terminals. For example, dimethylpolysiloxane, diethylamine having two hydroxyl groups at both ends of the molecule is preferable. Polysiloxane, diphenyl polysiloxane and the like can be mentioned. As the number average molecular weight of the polysilicone decreases,
If the ability to impart flexibility to the resulting polyester is reduced and increased, it becomes difficult to produce the polyester. Therefore, 100 to 20,000 is preferable, and 500 to 5,000 is more preferable.
It is 0.

The lactone reacts with an acid and a hydroxyl group by ring opening to add an aliphatic chain, imparts flexibility to the polyester, and has four or more carbon atoms in the ring. Are preferred, more preferably a 5- to 8-membered ring, such as ε-caprolactone, δ-valerolactone, γ-butyrolactone and the like.

The aromatic hydroxycarboxylic acid imparts rigidity and liquid crystallinity to the polyester, and includes salicylic acid, metahydroxybenzoic acid, parahydroxybenzoic acid, 3-chloro-4-hydroxybenzoic acid, and 3-bromo-carboxylic acid. 4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3
-Methyl-4-hydroxybenzoic acid, 3-phenyl-4-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4'-carboxybiphenyl and the like, and preferably, parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4'-carboxybiphenyl.

Further, an aromatic diol other than the dihydroxy compound [II] or an aromatic dicarboxylic acid may be contained in the aliphatic polyester in order to improve the mechanical properties and the like of the polyester.

Examples of the aromatic diol include hydroquinone, resorcin, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, and 4,4′-.
Dihydroxybiphenyl, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1, Examples thereof include 1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy) ethane, 1,4-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene.

The aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, metal salts of 5-sulfoisophthalic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, and 4,4'-dicarboxylic acid. Carboxydiphenyl sulfide, 4,4'-dicarboxydiphenyl sulfone,
3,3'-dicarboxybenzophenone, 4,4'-dicarboxybenzophenone, 1,2-bis (4-carboxyphenoxy) ethane, 1,4-dicarboxynaphthalene, or 2,6-dicarboxynaphthalene Can be

In the aliphatic polyester comprising the dihydroxy compound [II], the aliphatic diol and the aliphatic dicarboxylic acid, the heat resistance decreases as the content of the dihydroxy compound [II] decreases, and the elastic modulus increases as the content of the dihydroxy compound [II] increases. Since the flexibility is lowered and it becomes unsuitable as a thermoplastic elastomer, the content of the dihydroxy compound [II] is preferably 0.1 to 30 mol%, more preferably 0.5 to 20 mol% of all the monomers constituting the polyester. Mol%, more preferably 1.0 to 10 mol%. When polyalkylene oxide or polysilicone is used as the diol other than the aromatic, its structural unit is counted as one monomer. That is, polyethylene oxide having a degree of polymerization of 10 is counted as 10 monomers.

The above monohydroxy compound [III]
In the case of aliphatic polyesters composed of carboxylic acids, aliphatic diols and aliphatic dicarboxylic acids, the heat resistance decreases when the content of the monohydroxy compound [III] decreases, and when the content increases, the molecular weight of the aliphatic polyester does not increase sufficiently. Therefore, the content is preferably 0.1 to 20 mol% based on the total monomers constituting the aliphatic polyester. Further, the dihydroxy compound [II] and the monohydroxy compound [II
I], aliphatic diols and aliphatic dicarboxylic acids in aliphatic polyesters have lower heat resistance when the content of the hydroxy compound, which is the combination of dihydroxy compound [II] and monohydroxy compound [III], decreases, and increases when the content increases. As the flexibility and the molecular weight cannot be sufficiently increased,
0.1 to 30 in all monomers constituting the aliphatic polyester
Preferably, it is mol%. In this case, the ratio of the dihydroxy compound [II] to the monohydroxy compound [III] is preferably in a range satisfying 0 <[III] / ([II] + [III]) <2/3.

The aliphatic polyester composed of the above-mentioned components can be produced by using any of the following generally known polycondensation methods.

(1) A method of directly reacting a dicarboxylic acid with a diol component (including an aliphatic diol, a dihydroxy compound, a monohydroxy compound, etc.).

(2) A method of reacting a lower ester of a dicarboxylic acid with a diol component by utilizing transesterification.

(3) A method in which a halide of a dicarboxylic acid and a diol component are reacted in a suitable solvent such as pyridine.

(4) A method of reacting a metal alcoholate of a diol component with a halide of a dicarboxylic acid.

(5) A method of reacting an acetylated diol component with a dicarboxylic acid by utilizing transesterification.

It is also possible to regulate the structure of the obtained polyester by changing the order of addition of the dihydroxy compound [II] during the polymerization. For example, when the dihydroxy compound [II] is charged together with the dicarboxylic acid and other diol components, a random copolymer is easily obtained, and when the dihydroxy compound [II] is charged late in the polymerization, the block copolymer is used. Merging becomes easier to obtain. Also,
It is also possible to knead the previously synthesized dihydroxy compound [II] or the acetyl compound of the dihydroxy compound into pre-synthesized polyester under heating under reduced pressure and introduce a segment based on the dihydroxy compound [II] into the molecular chain by ethylene glycol or transesterification. It is.

In the polycondensation, a catalyst generally used for producing a polyester may be used. The catalyst includes metals such as lithium, sodium, potassium, cesium, magnesium, calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, boron, cadmium, and manganese. The organic metal compounds, organic acid salts, metal alkoxides, metal oxides and the like can be mentioned.

Particularly preferred catalysts are calcium acetate, stannous diacyl, stannous tetraacyl, dibutyltin oxide, dibutyltin dilaurate, dimethyltin malate,
Tin dioctanoate, tin tetraacetate, triisobutylaluminum, tetrabutyltitanate, germanium dioxide, and antimony trioxide. Two or more of these catalysts may be used in combination. In order to efficiently distill out water, alcohol, glycol, and the like produced as a by-product of the polymerization and obtain a high-molecular-weight polymer, it is preferable to reduce the pressure of the reaction system to 1 mmHg or less at the latter stage of the polymerization. The reaction temperature is generally between 150 and 350 ° C.

[Thermoplastic Polyurethane Elastomer] The thermoplastic polyurethane elastomer used in the present invention is obtained by reacting a diisocyanate and a polyol, and polyurethane is used as a hard segment and polyether or polyester is used as a soft segment. In order to introduce a hard segment into a molecule, for example, a diisocyanate such as 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and a short-chain such as ethylene glycol, propylene glycol, 1,4-butanediol, and bisphenol A are used. A chain glycol may be used, and a polyurethane chain formed by the polycondensation reaction acts as a hard segment. To introduce a soft segment, a long-chain polyol such as polyalkylene glycol, polyalkylene adipate, or polycaprolactone may be used.
The number average molecular weight of the long-chain polyol is preferably from 100 to 1,000, particularly preferably from 500 to 3,000. Polyol content in polyurethane elastomer is 40-95% by weight
Is preferred. If the amount is less than 40% by weight, the elasticity is insufficient. If the amount is more than 95% by weight, the mechanical strength of the polyurethane decreases.

Commercially available thermoplastic polyurethane elastomers include Pelecene (MD Chemicals), Milactone (Nippon Milactran), Parabrene (Nippon Polyurethane), Pandex (Dainippon Ink and Chemical), Takelac (Takeda Badesh), and Elastolane. (Urethane), iron rubber (Nippon Oil Seal), rezzamine (Dainichi Seika Kogyo), vibrene (Mitsui Nisso Urethane) and the like.

The thermoplastic elastomer composition of the present invention comprises:
It is obtained by mixing the aliphatic polyester (B) synthesized as described above with the thermoplastic polyurethane elastomer (A). The aliphatic polyester (B) is contained in an amount of 20 to 80% by weight, and the thermoplastic polyurethane elastomer ( A) is contained in an amount of 80 to 20% by weight.

In the elastomer composition containing the thermoplastic polyurethane elastomer (A), if the content of the elastomer (A) is less than 20% by weight, abrasion resistance and bending fatigue resistance are reduced, and 80% by weight. Chemical resistance,
Insufficient improvement in weather resistance and moldability.

The mixing method of the thermoplastic polyurethane elastomer (A) and the aliphatic polyester (B) is preferably melt mixing, and specifically includes a single-screw or twin-screw extruder, a kneader, a Banbury mixer, a heated roll, a plastograph, and the like. Can be used.

The following additives may be added to the thermoplastic elastomer composition of the present invention as long as practicality is not impaired. That is, glass fiber, carbon fiber, boron fiber, silicon carbide fiber, alumina fiber, amorphous fiber, inorganic fiber such as silicon / titanium / carbon fiber, organic fiber such as aramid fiber, calcium carbonate, titanium oxide, mica, talc. And inorganic fillers such as triphenyl phosphite, trilauryl phosphite, trisnonyl phenyl phosphite, 2-tert-butyl-α- (3-tert-
Butyl-4-hydroxyphenyl) -p-cumenylbis (p-
Heat stabilizers such as nonylphenyl) phosphite, flame retardants such as hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, and pentabromophenyl allyl ether; p-tert-butylphenyl salicylate;
2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5
UV absorbers such as trihydroxybutyrophenone; antioxidants such as butylhydroxyanisole, butylhydroxytoluene, distearylthiodipropionate, dilaurylthiodipropionate, and hindered phenol antioxidants; N, N- Antistatic agents such as bis (hydroxyethyl) alkylamine, alkylallyl sulfonate and alkyl sulfanate; inorganic substances such as barium sulfate, alumina and silicon oxide; sodium stearate;
Higher fatty acid salts such as barium stearate and sodium palmitate; organic compounds such as benzyl alcohol and benzophenone; and crystallization promoters such as highly crystallized polyethylene terephthalate and polytrans-cyclohexanedimethanol terephthalate.

The thermoplastic elastomer composition of the present invention comprises:
The molded body is formed by press molding, extrusion molding, injection molding, blow molding, or the like. The physical properties of the molded article can be arbitrarily changed depending on its constituent components, its compounding ratio and the like. When polyester is prepared as a thermoplastic elastomer, the molded article is suitably used for flexible molded articles such as automobile parts, hoses, belts, packings, paints, adhesives and the like.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

(Examples 1 and 2, Comparative Examples 1 and 2) Synthesis of Aliphatic Polyester Elastomer (B) A 2 liter glass flask equipped with a stirrer, thermometer, gas inlet and distillation port was used. , Dimethyl adipate 26
A monomer mixture of 8.2 g, 313.6 g of ethylene glycol and 60.9 g of 4,4 '''-dihydroxy-p-quarterphenyl (hereinafter referred to as DHQ) and 0.4 g of calcium acetate and 0.13 g of germanium oxide as a catalyst were added. After the atmosphere in the flask was replaced with nitrogen, the temperature was raised to 180 ° C to carry out a transesterification reaction. With the reaction, methanol was distilled off. It took about 2 hours for the transesterification reaction to complete, during which time stirring was continued. Next, 30
When the temperature was raised to 0 ° C and the mixture was stirred for 30 minutes, ethylene glycol was distilled out and the reaction mixture became homogeneous. The polycondensation reaction was carried out for 2 hours while the pressure in the flask was reduced to 1 mmHg or less. An extremely viscous white resin was obtained. The intrinsic viscosity of this resin was 1.0.

The aliphatic polyester elastomer (B) obtained above was mixed with a thermoplastic urethane elastomer (Cylactolan E 790 (C), manufactured by Nippon Milactran Co., Ltd.) in the ratio shown in Table 1, and the mixture was mixed with a plastograph. 17
The mixture was melt-kneaded at 0 ° C. for 30 minutes. In addition, Milactran E790
Has an adipate ester type polyether chain and a specific gravity of 1.21. The obtained elastomer composition was observed for coloring and for the presence of off-flavor, and then the following evaluation test was performed. Table 1 shows the results.

(A) Weather resistance test: The condition is set to 63 ° C. using a weather meter. One day and 14 days later, the sample was taken out and its elongation preservation rate (%) was measured. Table 1 shows the results.

(B) Chemical resistance test: No. 3 dumbbell (injection thickness 1500 kgf / cm ² , mold temperature 70 ° C., cylinder temperature 21
0 ° C.) according to JIS K 6301.
After the elastomer composition was immersed in a 40% NaOH solution and ethanol solvent at 23 ° C. for 5 days, the elastomer composition was taken out and its surface condition was observed. The chemical resistance was graded from A to D from the surface state. Table 1 shows the results.

[0053]

[Table 1]

* However, A: no change, B: almost no change, C: slightly swells the surface, D: swells and becomes brittle.

[0055]

The elastomer composition of the present invention has a temperature of 300.degree.
Above, an aliphatic polyester containing a soluble hydroxy compound as a constituent component is blended. In this aliphatic polyester, a segment based on a dihydroxy compound or a monohydroxy compound having a high crystallinity and a high melting point is introduced into an aliphatic polyester mainly composed of an aliphatic dicarboxylic acid and an aliphatic diol. The elastomer composition of the present invention obtained by mixing the above has not only the performance as a thermoplastic elastomer but also excellent weather resistance, chemical resistance, mechanical strength, moldability and the like.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akihiro Niki 2-2, Hyakuyama, Shimamoto-cho, Mishima-gun, Osaka (72) Inventor Toranosuke Saito 5-17-21 Yamatedai, Ibaraki-shi, Osaka (72) Inventor Hiroki Kadomachi 1-13-1 Minami Kasugaoka, Ibaraki-shi, Osaka (72) Inventor Daishiro Kishimoto 2-11-20 Mishimaoka, Ibaraki-shi, Osaka Ume Yama Mansion 102

Claims (1)

(57) [Claims] 1. A thermoplastic polyurethane elastomer (A)
(B) an aliphatic dicarboxylic acid and an aliphatic diol represented by the following formula [I], and a dihydroxy compound represented by the following formula [II] and (III): And 80 to 20% by weight of an aliphatic polyester containing at least one of the monohydroxy compounds represented by the following formulas: HOOC- (CH ₂ ) n-COOH [I] (wherein, n represents an integer of 0 to 10.) (Wherein R ¹ and R ^{2 each} independently represent an alkylene group;
Or 4, and q and r independently represent 0 or an integer of 1 or more. ) (In the formula, R ³ represents an alkylene group, 1 is 2 or 3, and m represents 0 or an integer of 1 or more.)