JP2000273140A - Method for producing ester-based elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ester elastomer which is excellent in mechanical properties at high temperature, especially excellent in creep resistance and bending fatigue resistance at high temperature and capable of producing an ester elastomer having a high melt viscosity. Production method. SOLUTION: A polyester-based copolymer comprising a repeating short-chain and long-chain polyester component represented by a specific formula, wherein a short-chain component is 50 to 95% by weight and a long-chain component is 50 to 5% by weight ( a) 100 parts by weight, the general formula -R ₃ -O- (R ₃ is a polyether (B) 50 to 500 parts by weight of a repeating unit represented by the alkylene group) having 2 to 8 carbon atoms, and the general formula CON-R
An isocyanate component represented by _4- NCO (R ₄ is an alkylene group having 2 to 15 carbon atoms, a phenylene group, or a methylene group or a functional group in which an alkylene group and a phenylene group are bonded);
(C) A method for producing an ester elastomer in which 10 to 100 parts by weight are melt-mixed, and then a polyfunctional alcohol is added and melt-mixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ester-based elastomer having excellent mechanical properties at high temperatures, particularly excellent creep resistance and bending fatigue resistance at high temperatures, and having a high melt viscosity suitable for extrusion molding and blow molding. The present invention relates to a method for producing an ester-based elastomer that can be provided.

[0002]

2. Description of the Related Art In recent years, due to increasing awareness of environmental issues,
The replacement of recyclable materials in various industrial fields is accelerating. Thermoplastic elastomer (TP
E) has been attracting attention for a long time because it exhibits rubber elasticity at normal temperature but exhibits plasticity at high temperature and can be molded normally, and is used in various applications in the fields of automobiles, various industries, and the like. became. Among them, polyester-based elastomers (TPEE) have excellent mechanical strength, oil resistance, abrasion resistance, and flex fatigue resistance, and are therefore used in a wide range of industrial fields mainly in the automobile field. However, TPE
E has the disadvantages that it has higher hardness than ordinary rubber and lacks flexibility, and lacks creep resistance due to large compression set at the time of large deformation and high temperature, and its improvement has been desired.

[0003] On the other hand, when a thermoplastic resin is molded by an extrusion molding method or a blow molding method, a high melt viscosity is generally required. However, TPEE has a relatively low melt viscosity. There is a problem that molding failure such as uneven wall thickness occurs even if it is attempted to obtain. With respect to the improvement of the creep resistance of TPEE, attempts to improve the creep resistance by increasing the degree of polymerization have been known (see, for example, JP-A-52-121699). It was desired. Further, as a technique for increasing the melt viscosity of TPEE, a technique of melt-mixing a diepoxidized dough and a metal salt of a carboxylic acid with a polyetherester elastic material is disclosed in, for example, JP-A-57-36124.

[0004]

However, according to the study of the present inventors, the polyester elastomer obtained by the method described in the above-mentioned Japanese Patent Application Laid-Open No. Sho 57-36124,
It is presumed to be caused by the metal salt of the carboxylic acid used as the catalyst, but there was an adverse effect such as a decrease in durability, particularly hydrolysis resistance. The present invention has been made in view of the above-mentioned problems relating to the conventional method for producing an ester-based elastomer, and has excellent mechanical properties at high temperatures, in particular, excellent resistance to creep and bending fatigue at high temperatures, and high melt viscosity. It is an object of the present invention to provide a method for producing an ester-based elastomer, which is capable of producing an elastomer.

[0005]

In order to achieve the above object, a method for producing an ester-based elastomer according to the present invention comprises a short-chain polyester component represented by the general formula (1) and a compound represented by the general formula (2). 100 parts by weight of a polyester copolymer (A) comprising 50 to 95% by weight of the short-chain polyester component and 50 to 5% by weight of the long-chain polyester component. formula
After melt-mixing 50 to 500 parts by weight of a polyether (B) composed of a repeating unit represented by (3), and 10 to 100 parts by weight of an isocyanate component (C) represented by the general formula (4) Characterized in that a polyfunctional alcohol is added and melt-mixed.

[0006]

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[0007]

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[0008]

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[0009]

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The polyester copolymer (A) used in the present invention is composed of a repeating short-chain polyester component represented by the general formula (1) and a long-chain polyester component represented by the general formula (2). You. As the polyester copolymer (A), for example, a known polyester terelastomer obtained by reacting an aromatic dicarboxylic acid or an ester-forming derivative thereof with a low molecular weight diol and a polyether can be used. Examples of the aromatic dicarboxylic acid include, for example, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, and the like.The ester-forming derivatives thereof include dimethyl terephthalate, dimethyl isophthalate, Examples thereof include dimethyl orthophthalate, dimethyl naphthalenedicarboxylate, and dimethyl paraphenylenedicarboxylate.

Examples of the low molecular weight diol for obtaining the polyester copolymer (A) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 4 Butanediol, neopentyl glycol, 1,5-pentanediol, 1,6
-Hexanediol and the like, which may be used alone or in combination of two or more.

Examples of the polyether for obtaining the polyester copolymer (A) include, for example, polyethylene glycol, poly-1,3-propylene glycol, poly1,2 propylene glycol, polytetramethylene glycol,
And polyhexamethylene glycol. Among them, polytetramethylene glycol is preferable in terms of excellent mechanical properties and weather resistance. Examples of commercially available products include "PTHF" manufactured by BASF and "PTMG" manufactured by Mitsubishi Chemical Corporation.

The above polyether has a number average molecular weight of 50.
It is preferable to use one having 0 to 5,000, and more preferably one having 500 to 2,000. When the number average molecular weight is less than 500, the resulting polyester copolymer
The blockability of (A) is lowered and the melting point is lowered, and as a result,
The mechanical strength at a high temperature of the ester elastomer obtained by the present invention is reduced. Further, the number average molecular weight is 5,0
If it exceeds 00, the compatibility with the polyether (B) becomes low, so that the degree of polymerization of the ester elastomer does not increase, and an elastomer having sufficient strength cannot be obtained.

The above polyester copolymer (A) can be polymerized by a known method. In particular,
Aromatic dicarboxylic acid and its ester-forming derivative, together with polyether and excess low molecular weight diol, are heated to 200 ° C. in the presence of a catalyst to carry out transesterification,
Subsequently, the polyester-based copolymer (A) can be obtained by performing a polycondensation reaction at 240 ° C. under reduced pressure.

The proportion of the short-chain polyester component in the components of the polyester copolymer (A) is 50 to 95.
%, Preferably 70 to 90% by weight. When the content of the short-chain polyester component is less than 50% by weight, the melting point of the polyester copolymer (A) is low, which adversely affects the mechanical strength of the ester elastomer at high temperatures. If it exceeds 95% by weight, the degree of polymerization of the ester elastomer does not increase due to low compatibility with the polyether (B), and an elastomer having sufficient strength cannot be obtained.

The polyether (B) used in the present invention comprises a repeating unit represented by the general formula (3).
As such a polyether, for example, the same polyether as that used for obtaining the above-mentioned polyester-based copolymer (A) is suitably used.

The isocyanate component used in the present invention
(C) is represented by the above general formula (4), and its structure is not particularly limited as long as it is a compound having two isocyanate groups in the same molecule.

Examples of the isocyanate component (C) include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate,
Aromatic diisocyanates such as naphthalene diisocyanate; 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butane diisocyanate,
Examples thereof include aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, and hydrogenated 4,4′-diphenylmethane diisocyanate.

The polyfunctional alcohol used in the present invention is an alcohol having two or more hydroxyl groups in one molecule, and its structure is not particularly limited. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3 butanediol, 1,4 butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol And diols such as diols, triols such as trimethylolpropane and glycerin, and alcohols having four or more hydroxyl groups in the same molecule such as pentaerythritol. These may be used alone or in combination of two or more. Of these, the melt viscosity of the elastomer is relatively easy to control,
Alcohols having 3 or 4 hydroxyl groups are preferably used.

The ester elastomer of the present invention comprises 50 to 500 parts by weight of the polyether (B), 10 to 100 parts by weight of the isocyanate component (C), and 100 parts by weight of the polyester copolymer (A). It is usually obtained by melting and mixing 0.01 to 20 parts by weight of a polyfunctional alcohol. When the amount of the polyether (B) is less than 50 parts by weight with respect to 100 parts by weight of the polyester-based copolymer (A), the ester elastomer does not have sufficient flexibility and exceeds 500 parts by weight. And sufficient mechanical strength cannot be obtained. Preferably, it is 100 to 300 parts by weight.

When the amount of the isocyanate component (C) is less than 10 parts by weight based on 100 parts by weight of the polyester copolymer (A), the ester elastomer does not become a high molecular weight polymer and has low mechanical strength. It becomes something, 100
When the amount exceeds the weight part, the ester elastomer becomes inferior in flexibility. Preferably, 30 to 70
Parts by weight.

When the amount of the polyfunctional alcohol is less than 0.01 part by weight based on 100 parts by weight of the polyester copolymer (A), the ester elastomer may not have a sufficient melt viscosity in some cases. If the amount exceeds the weight part, gelation may progress depending on the type of polyfunctional alcohol, and the melt fluidity may be lost. Preferably, 0.1
To 10 parts by weight.

An extruder is usually used to melt-mix the polyester copolymer (A), polyether (B), isocyanate component (C) and polyfunctional alcohol. The type of the extruder is not particularly limited, and a single-screw extruder or a twin-screw extruder is used. A screw extruder is used, and more preferably, a co-rotating meshing twin screw extruder is used.

The extrusion temperature is preferably from 180 to 260 ° C. 1
If the temperature is lower than 80 ° C, the reaction is difficult because the polyester copolymer (A) does not melt, and it is difficult to obtain an ester elastomer as a high molecular weight polymer. (A) and isocyanate are decomposed, and it is difficult to obtain an ester elastomer having sufficient strength. A more preferable range of the melt mixing temperature is 200 to 24.
0 ° C.

In the production method of the present invention, the polyester-based copolymer (A), the polyether (B) and the isocyanate component (C) are melt-mixed, and the polyfunctional alcohol is supplied after the initiation of the elastomer formation reaction. is important. A method of supplying a polyfunctional alcohol before the start of the elastomer formation reaction, for example, a polyester-based copolymer
In the method of simultaneously supplying and melt-mixing (A), polyether (B), isocyanate component (C) and polyfunctional alcohol, polyester-based copolymer (A), polyether
Due to the difference in reactivity between (B) and each of the polyfunctional alcohols and the isocyanate component (C), a non-uniform reaction occurs and an elastomer having sufficient mechanical strength cannot be obtained.

In the present invention, a catalyst may be used at the time of melting and mixing the above components. Examples of the catalyst include stannous diacyl, stannous tetraacyl, dibutyltin oxide,
Dibutyltin dilaurate, 2-ethylhexanetin, dimethyltin malate, tin dioctanoate, tin tetraacetate, triethyleneamine, diethyleneamine, triethylamine, metal salts of naphthenate, metal octylate, triisobutylaluminum, tetrabutyltitanate, calcium acetate , Germanium dioxide, antimony trioxide and the like are preferred. Two or more of the above catalysts may be used in combination.

Stabilizers may be used in the ester elastomer obtained according to the present invention, for example, 1,3,5-
Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-
(Hydroxybenzyl) benzene, 3,9-bis {2- [3- (3
-Tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl {-2,4,8,10-
Hindered phenolic antioxidants such as tetraoxaspiro [5,5] undecane; tris (2,4-di-t-butylphenyl) phosphite, trilauryl phosphite, 2-
t-butyl-α- (3-t-butyl-4-hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite, dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thio Examples thereof include heat stabilizers such as dipropionate, pentaerythryltetrakis (3-laurylthiopropionate), and ditridecyl 3,3'-thiodipropionate.

The ester-based elastomer obtained by the present invention includes fibers, flame retardants, ultraviolet absorbers, antistatic agents, inorganic fillers, inorganic substances, higher fatty acid salts, etc. within a range that does not impair the utility during or after the production. May be added. Examples of the fibers include inorganic fibers such as glass fibers, carbon fibers, boron fibers, silicon carbide fibers, alumina fibers, amorphous fibers, and silicon / titanium / carbon fibers; and organic fibers such as aramid fibers. Examples of the flame retardant include hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate,
Pentabromophenyl allyl ether and the like, as the ultraviolet absorber, for example, P-tert-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone and the like.

Examples of the antistatic agent include N, N-
Bis (hydroxyethyl) alkylamine, alkyl allyl sulfonate, alkyl sulfanate and the like can be mentioned. Examples of the inorganic filler include calcium carbonate, titanium oxide, mica, and talc, and examples of the inorganic substance include barium sulfate, alumina, and silicon oxide. As the higher fatty acid salt, for example, sodium stearate, barium stearate,
And sodium palmitate.

The ester-based elastomer of the present invention may be used after mixing thermoplastic resins and rubber components other than those described above to modify the properties thereof.

Examples of the thermoplastic resin include polyolefin, modified polyolefin, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulfone, polyester and the like. As the rubber component, for example, natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPDM), polychloroprene, butyl rubber, acrylic Examples include rubber, silicone rubber, urethane rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, PVC-based thermoplastic elastomer, ester-based thermoplastic elastomer, and amide-based thermoplastic elastomer.

The ester-based elastomer of the present invention can be formed into a molded article by a commonly used molding method such as press molding, extrusion molding and blow molding. The molding temperature varies depending on the melting point of the ester-based elastomer and the molding method, but 160 to 280 ° C is suitable. If the temperature is lower than 160 ° C, a uniform molded article cannot be obtained because the fluidity of the ester elastomer is low. If the temperature exceeds 280 ° C, the ester elastomer is decomposed, and it is difficult to obtain an ester elastomer having sufficient strength. Becomes

The molded article obtained by using the ester-based elastomer of the present invention is suitably used for, for example, automobile parts, electric and electronic parts, industrial parts, sports goods, medical goods and the like. Examples of automobile parts include boots such as constant velocity joint boots and rack and opinion boots; ball joint seals; safety belt parts;
Bumper fascia; emblem; mall, and the like. Examples of the electric and electronic components include a wire covering material, gears, a rubber switch, a membrane switch, a tact switch, an O-ring, and the like.

Examples of the sporting goods include shoe soles and balls for ball contact. Examples of the medical supplies include a medical tube, a blood transfusion pack,
Catheters and the like. In addition to the above applications, elastic fibers,
It can be suitably used as an elastic sheet, a composite sheet, a hot melt adhesive, a material for alloying with other resins, and the like.

(Function) In the method for producing an ester-based elastomer of the present invention, since the polyfunctional alcohol is added during the elastomer-forming reaction, the isocyanate component (C) can be used without adding a metal salt of carboxylic acid as a catalyst. According to the present invention, it is possible to obtain an ester-based elastomer which has a high melt viscosity and does not impair the hydrolysis resistance and the like, since it easily reacts to increase the molecular weight or generate a branch.
Further, as a raw material, a polyester-based copolymer (A) composed of a repeating unit represented by the above specific general formula, a polyether (B) represented by a specific general formula, and a specific general formula Isocyanate component (C)
The ester-based elastomer obtained by the present invention has high blockability of the hard segment component and the soft segment component, and it is considered that the crystal formed by the short-chain polyester component constitutes a cross-linking point and exhibits properties as an elastomer. Can be

In particular, the polyester-based copolymer (A) as an ester-based elastomer contains, in the molecule, a portion having a high proportion of a short-chain polyester component represented by the general formula (1), which is a hard segment, and a soft segment. Is a general formula
(2) is composed of a portion having a high proportion of the long-chain polyether polyester component, so that the short-chain polyester component is easier to crystallize than the conventional ester-based elastomer having the same degree of flexibility, As a result, a strong crosslinking point is formed, and excellent mechanical properties at high temperatures, particularly creep resistance, can be exhibited.

[0037]

[Glass transition temperature Tg, melting point]

The measurement was performed at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC). [Surface hardness] The surface hardness was measured at 23 ° C according to JIS K7215.

[Tensile Properties] Tensile strength and tensile elongation at room temperature (23 ° C.) were evaluated according to JIS K6301. [Compression Permanent Strain] According to JIS K6301, creep resistance was evaluated by measuring at 100 ° C. with a compression strain amount of 25%.

[Melting temperature] Using a Capillograph 1B manufactured by Toyo Seiki, 220 ° C, 128
It was measured under the condition of sec- ¹ . [Hydrolysis resistance] Using a pressure cooker tester, a test piece immersed at 120 ° C for 72 hours in accordance with JIS K6301 at room temperature (23 ° C)
Was measured, and evaluated by the retention of the tensile strength before immersion.

Synthesis of polyester copolymer (A) 100 parts by weight of dimethyl terephthalate, 1,4-butanediol
102 parts by weight, 48 parts by weight of polytetramethylene glycol having a number average molecular weight of about 1000 (PTF1000 manufactured by BASF) (b), 0.3 parts by weight of tetrabutyl titanate as a catalyst, and 1,3,5-trimethyl-2,4 as a stabilizer , 6-Tris (3,5-di-
0.3 parts by weight of t-butyl-4-hydroxybenzyl) benzene, tris (2,4-di-t-butylphenyl) phosphite
0.3 part by weight was added, and the reaction system was kept at 200 ° C. for 3 hours under nitrogen to carry out a transesterification reaction. The progress of the transesterification reaction was confirmed by measuring the amount of methanol distilled out. After the transesterification proceeded, the temperature was raised to 240 ° C. in 20 minutes, and the pressure was reduced. The polymerization system reached a reduced pressure of 2 mmHg or less in 20 minutes. As a result of a polycondensation reaction for 20 minutes in this state, 160 parts by weight of a white polyester copolymer (a) was obtained.

Example 1 The above polyester copolymer
(a) 100 parts by weight, the above polytetramethylene glycol (b)
110 parts by weight, 4,4'-diphenylmethane diisocyanate
36 parts by weight, and 1 part by weight of 1,4-butanediol as a polyfunctional alcohol were further fed to a twin-screw extruder (L / D manufactured by Berstorf)
= 40 mm) and melt kneading at 220 ° C (residence time 23
0 second) to obtain an ester-based elastomer pellet.
The extrusion temperature was 220 ° C.

The raw material was supplied from a polyester copolymer.
(a) and polytetramethylene glycol (b) were fed through the feed port of the extruder, and 4,4-diphenylmethane diisocyanate was fed through the injection port provided in the fourth cylinder. The injection was performed from an inlet provided in 6 cylinders. Using the obtained pellets, a 2 mm-thick ester-based elastomer sheet was prepared by press molding (press temperature: 230 ° C.), and various physical properties were measured. The results are shown in Table 1.

Example 2 Ester elastomer pellets were obtained in exactly the same manner as in Example 1 except that 1 part by weight of pentaerythritol was used as the polyfunctional alcohol. Using the obtained pellets, a sheet having a thickness of 2 mm was prepared by press molding (press temperature: 230 ° C.), and various physical properties were measured. The results are shown in Table 1.

Comparative Example 1 Ester elastomer pellets were obtained in exactly the same manner as in Example 1, except that the polyfunctional alcohol was not added. Using the obtained pellets, a sheet having a thickness of 2 mm was prepared by press molding (press temperature: 230 ° C.), and various physical properties were measured. The results are shown in Table 1.

(Comparative Example 2) "Denacol EX811" manufactured by Nagase Kasei Co., Ltd. as an epoxy compound was added to pellets of an ester elastomer obtained by the same method as in Example 1 except that no polyfunctional alcohol was added.
(Polyethylene glycol diglycidyl ether) 3 parts by weight, and potassium laurate 0.3 part by weight,
Using a twin-screw extruder (L / D = 40 mm, manufactured by Berstorf Co.), the mixture was melt-kneaded at 200 ° C. (residence time 230 seconds) to obtain pellets of the ester elastomer again. All of the raw materials were supplied from the extruder raw material supply port. Using the obtained pellets, a 2 mm-thick ester-based elastomer sheet was prepared by press molding (press temperature: 230 ° C.), and various physical properties were measured. The results are shown in Table 1.

Comparative Example 3 Polyester Copolymer (a)
And polytetramethylene glycol (b) and polyfunctional alcohol (1,4-butanediol) were supplied from the raw material supply port of the extruder, and 4,4'-diphenylmethane diisocyanate was supplied from the injection port provided in the fourth cylinder. Except for this, melt kneading was carried out in exactly the same manner as in Example 1, but no elastomer was obtained.

[0047]

[Table 1]

[0048]

According to the present invention, the method for producing the ester-based elastomer of the present invention and the constitution as described above are provided. According to the present invention, both the flexibility and the mechanical properties at high temperatures, particularly the creep resistance, are obtained, and the melt viscosity is further improved. An ester elastomer which is high and can be suitably used for extrusion molding and blow molding is obtained.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akihiko Fujiwara 2-1 Hyakuyama, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sekisui Chemical Co., Ltd. F term (reference) 4J034 BA08 CA03 CA04 CA05 CB03 CB04 CB05 CC01 DB04 DC02 DC03 DF01 DF16 DF21 DF22 DG02 DH02 DH06 HA01 HA07 HC03 HC12 HC13 QB15 RA02 RA03 RA08 RA11 RA12 RA14 SA02

Claims (1)

[Claims] 1. A short-chain polyester component represented by the following general formula (1) and a long-chain polyester component represented by the following general formula (2):
0 to 95% by weight, and the long-chain polyester component is 50 to 5%.
100% by weight of a polyester copolymer (A), 50 to 500 parts by weight of a polyether (B) composed of a repeating unit represented by the general formula (3), and a compound represented by the general formula (4). A method for producing an ester-based elastomer, wherein 10 to 100 parts by weight of the isocyanate component (C) is melt-mixed, and then a polyfunctional alcohol is added and melt-mixed. Embedded image Embedded image Embedded image Embedded image