JP2002194190A - Polyester block copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester composition capable of forming a molded article having superior mechanical strength and a suppressed stick-slip effect under whatever server conditions such as in an atmosphere of high temperatures, and further to provide a flexible boot for a universal coupling comprising the above polyester composition which does not generate abnormal sliding sound caused by stick-slip for an extensive period under whatever severe conditions such as in an atmosphere at high temperatures. SOLUTION: The polyester block copolymer is prepared by mixing a polyester block copolymer with a fatty acid amide compound and introducing a compound into the polyester block copolymer as a specific repeating unit. The flexible boot for a universal coupling is manufactured by using the above polyester block copolymer composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to rubber properties such as flexibility and elastic recovery, mechanical properties, durability such as bending fatigue resistance, moldability, as well as sliding properties, especially the effect of suppressing stick-slip. The present invention relates to a polyester block copolymer composition that lasts for a long period of time, and is preferably used for a flexible boot that is attached to a universal joint to prevent dust and that holds grease for lubricating the universal joint. It relates to a coalescing composition.

[0002]

2. Description of the Related Art Crystalline aromatic polyester units such as polybutylene terephthalate units are used as hard segments, and aliphatic polyether units such as poly (alkylene oxide) glycol and / or aliphatic polyester units such as polylactone are used as soft segments. Polyester block copolymers as segments are excellent in mechanical properties such as mechanical strength, impact resistance, elastic recovery, flexibility, etc. and low-temperature and high-temperature properties. Its applications are expanding to parts and electrical / electronic parts, fibers, films, etc.

[0003] However, in applications where the molded article of the polyester block copolymer rubs against other parts or itself in the use environment, slidability is important in addition to the above-mentioned properties. In other words, in applications where the polyester block copolymer molded article is used while receiving friction with other materials or its own material, especially when the load applied during sliding is large, parts made of the polyester block copolymer are worn out due to wear. May result in damage. In addition, even when the load during sliding is small and no significant wear occurs,
Poor working feel, poor operation, and squeaking noise when sliding molded products due to stick-slip. An application in which the abnormal sliding noise at the time of sliding is a problem is a flexible boot application mounted on a universal joint.

[0004] A flexible boot for the purpose of dust-proofing and grease holding of a universal joint such as a constant velocity joint of an automobile has a shape in which a large-diameter portion and a small-diameter portion are connected by a bellows portion. Mainly chloroprene rubber has been used. However, in the case of flexible boots for constant velocity joints in automobiles, chloroprene rubber lacks durability against repeated bending stress and durability against ozone in the atmosphere. As a result, cracks are generated in the valleys of the bellows, resulting in a problem of damage. Further, since it is inferior in cold resistance, it hardens when used in extremely cold regions and may be damaged. In addition, chloroprene rubber flexible boots with low mechanical strength can be damaged by stepping stones during running, or abnormally expanded during high-speed rotation such as high-speed running of automobiles, resulting in deformation or damage due to interference with other parts. Problems arise.

[0005] In order to overcome the problems of the chloroprene rubber flexible boot, the polyester block copolymer is excellent in bending fatigue resistance, ozone resistance, cold resistance and mechanical strength. Coalescing is widely used for flexible boot applications.

However, when a universal joint fitted with a flexible boot formed of a polyester block copolymer bends and rotates at a high angle, adjacent side surfaces of the peaks forming the bellows of the flexible boot come into contact. , An abnormal sliding noise may occur.

[0007] In order to reduce such sliding defects, the shape of a molded part is changed, a surface treatment is performed to cause fine irregularities on the sliding surface of the molded part, or a lubricant is applied. Or other measures are required. However, with these techniques, the shape of the molded product is limited, special processing and labor are required, and sufficient effects may not always be obtained. Therefore, the implementation of these methods has limitations.

Therefore, it has been proposed to provide a sliding property to the polyester block copolymer to solve the problem in the case where the molded article is used under friction. As a method of imparting slidability to the polyester block copolymer itself, it has been proposed to incorporate various slidability improvers. For example, JP-A-52-65552 discloses solid lubricants and A higher fatty acid derivative such as acid amide, a poly (alkylene oxide) monoalkyl ether in JP-A-3-139557, a silicone resin in JP-A-3-229755, and No. 279557 proposes adding a long-chain hydrocarbon group-substituted amide such as a saturated aliphatic hydrocarbon group-substituted amide as a slidability improving agent.

The coefficient of friction of the surface of a molded article made of the polyester block copolymer disclosed in these publications is reduced, wear due to sliding when the load applied during sliding is large, and damage to parts is prevented. it can. However, stick-slip when sliding, especially when using flexible boots for constant velocity joints in automobiles, etc.
With respect to sliding noise caused by slip, the effects disclosed in these inventions are insufficient in preventing effect for the following reasons.

There are various causes of stick-slip. One of the causes is that the friction coefficient of the sliding surface is not constant and the friction coefficient varies depending on the location. In this way, when the other material or its own material is slid against a surface having a different friction coefficient depending on the location, in a portion where the friction coefficient is small, the sliding resistance is small and the mating material moves smoothly. Go. However, in portions where the surface slips poorly, the sliding resistance suddenly increases. Moving further,
When approaching a portion having a small coefficient of friction, the sliding resistance rapidly decreases. It is considered that stick-slip is generated by this repetition.

[0011] In the polyester block copolymer composition disclosed in the above-mentioned invention, an additive added as a slidability improver is added to the surface of the molded article to prevent the occurrence of such stick-slip. The time required to uniformly exude is long, and in the stage of uniform exudation, a portion having a small friction coefficient and a relatively large portion coexist on the surface. In such a state, stick-slip easily occurs, and the sliding noise of the flexible boot cannot be suppressed.

For suppressing the sliding noise when sliding the flexible boot, for example, Japanese Patent Application Laid-Open No. HEI 6-117535 discloses a flexible boot using a polyester block copolymer containing a silicone resin as a friction and wear property improving agent. Boots have been proposed. Also, Japanese Patent Laid-Open No. 9-17 / 1997
No. 7971 proposes a flexible boot using a polyester block copolymer containing ethylene bisalkyleneamide which is a reaction product of a higher fatty acid and ethylenediamine. Furthermore, the present inventors have also proposed in JP-A-11-130952 a polyester block copolymer composition to which a poly (alkylene oxide) ether having hydroxyl groups at both ends is added.

[0013]

However, Japanese Patent Application Laid-Open No.
The polyester block copolymer to which a silicone resin is added as a friction and wear property improving agent disclosed in Japanese Patent No. 17535 can suppress stick-slip,
If the addition amount is small, the silicone resin that has oozed out on the surface is wiped off by friction, and the stick-slip suppressing effect is insufficiently persistent. Also, in order to improve the persistence of the stick-slip suppression effect, if the added amount of the silicone resin is increased, the compatibility between the polyester block copolymer and the silicone resin is poor, so that delamination occurs during molding of the flexible boot, The durability as a flexible boot is significantly impaired. Therefore, the polyester block copolymer composition to which the silicone resin has been added cannot suppress stick-slip on the surface of the flexible boot for a long period of time.

On the other hand, in the polyester block copolymer containing ethylenebisalkyleneamide disclosed in Japanese Patent Application Laid-Open No. Hei 9-177971, the polyester block copolymer of ethylenebisalkyleneamide added as a friction and wear property improving agent is used. Since it has almost no compatibility with the polymer, it exudes to the surface of the molded article in a very short time, and effectively suppresses stick-slip. However, since there is almost no affinity with the polyester block copolymer, the additive oozing out on the surface easily falls off due to friction and abrasion, and the duration of the stick-slip suppressing effect is insufficient. In addition, if the amount of ethylenebisalkyleneamide is increased to improve the durability of the stick-slip control effect, the coefficient of friction will be extremely reduced, and the adhesion of the portion in contact with the universal shaft will be reduced, and The problem that the grease to be held by the boot leaks occurs.
Therefore, the polyester block copolymer composition containing ethylenebisalkyleneamide cannot provide a flexible boot capable of suppressing stick and slip over a long period of time.

Further, the present inventors have disclosed in Japanese Patent Application Laid-Open No. 11-130.
In the polyester block copolymer composition containing a poly (alkylene oxide) ether having hydroxyl groups at both ends disclosed in JP-A-952, the additive uniformly covers the surface of the molded product, and the stick is effectively treated. -Slip is suppressed. However, since poly (alkylene oxide) ethers have a melting point of about 100 ° C. or lower, the ambient temperature may be higher than the melting point in applications such as flexible boots for constant velocity joints of automobiles. Poly (alkylene oxide) liquefied at ambient temperature above melting point
Additives such as ether are easily wiped off by the friction of the bellows of the flexible boot, and the persistence of stick-slip control under high temperature conditions is insufficient.

The present inventors have studied the improvement of the slidability of a polyester block copolymer molded article with the aim of suppressing the stick-slip, and in particular, the effect of suppressing the stick-slip over a long period of time. In the present invention, it was found that a molded article made of a polyester block copolymer to which a sound suppressant had been added was not only free from stick-slip, but also maintained a stick-slip inhibitory effect under any use conditions for a long period of time. Reached.

[0017]

That is, the present invention provides a high-melting crystalline polymer segment (a) mainly composed of a crystalline aromatic polyester unit and an aliphatic polyether unit and / or an aliphatic polyester unit. A mixture of one or more fatty acid amide compounds (B) represented by the following structural formula (I) is added to a polyester block copolymer (A) having a low melting polymer segment (b) as a main component. In a polyester block copolymer composition comprising one or more compounds (C) represented by the following structural formula (II), the compounding amount of the fatty acid amide compound (B) is For 100 parts by weight of the block copolymer (A),
0.005 to 5 parts by weight, the compounding amount of the compound (C) is 0.0
1 to 20 parts by weight of a polyester block copolymer composition.

[0018]

Embedded image (Wherein R 1 and R 2 represent a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, and R 1 and R 2 may be the same group. Good, R3, R4
Represents a hydrocarbon group obtained by further removing one primary hydrogen from those hydrocarbon groups, and R3 and R4 may be the same group. )

[0019]

Embedded image (In the above formula, R5 is a group obtained by removing 2 hydrogen atoms from a hydrocarbon compound having 1 to 6 carbon atoms. X represents an integer of 1 to 1000.)

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

High melting point crystalline polymer segment (a) of the polyester block copolymer (A) used in the present invention
Is a polyester formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol, and is preferably terephthalic acid and / or polybutylene terephthalate derived from dimethyl terephthalate and 1,4-butanediol, Isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-
A dicarboxylic acid component such as 4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or an ester-forming derivative thereof;
00 or less diols, for example, aliphatic diols such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol;
Alicyclic diols such as cyclohexane dimethanol and tricyclodecane dimethylol, xylylene glycol,
Bis (p-hydroxy) diphenyl, bis (p-hydroxyphenyl) propane, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4-
(2-hydroxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane, 4,4′-dihydroxy-p-tert-phenyl,
Polyesters derived from aromatic diols such as 4,4'-dihydroxy-p-quater-phenyl and the like, or copolymer polyesters using two or more of these dicarboxylic acid components and diol components in combination may be used.
It is also possible to copolymerize a trifunctional or higher polyfunctional carboxylic acid component, a polyfunctional oxyacid component, a polyfunctional hydroxy component and the like in a range of 5 mol% or less.

The low-melting polymer segment (b) of the polyester block copolymer (A) used in the present invention is an aliphatic polyether and / or an aliphatic polyester. Examples of the aliphatic polyether include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol,
Examples thereof include poly (hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, an ethylene oxide addition polymer of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Examples of the aliphatic polyester include poly (ε-caprolactone), polyenantholactone, polycaprylolactone, polybutylene adipate,
Examples include polyethylene adipate. From the elastic properties of the polyester block copolymer obtained from these aliphatic polyethers and / or aliphatic polyesters, poly (tetramethylene oxide) glycol, ethylene oxide adduct of poly (propylene oxide) glycol, poly (ε-caprolactone) ), Polybutylene adipate, polyethylene adipate and the like are preferred.
Further, the number average molecular weight of these low melting point polymer segments is preferably about 300 to 6000 in a copolymerized state.

The low melting point polymer segment (b) in the polyester block copolymer (A) used in the present invention
Is preferably 10 to 80% by weight, more preferably 15 to 75% by weight.

The polyester block copolymer (A) used in the present invention can be produced by a known method.
For example, a method of subjecting a lower alcohol diester of a dicarboxylic acid, an excessive amount of a low-molecular-weight glycol, and a low-melting polymer segment component to a transesterification reaction in the presence of a catalyst, and polycondensing the obtained reaction product. Alternatively, a dicarboxylic acid, an excess amount of glycol and a low melting polymer segment component are subjected to an esterification reaction in the presence of a catalyst, and the resulting reaction product is polycondensed. A method in which a high-melting-point crystalline segment is prepared in advance, and a low-melting-point segment component is added thereto to randomize the ester by a transesterification reaction. A method of connecting a high melting crystalline segment and a low melting polymer segment with a chain linking agent. Further, when poly (ε-caprolactone) is used for the low-melting polymer segment, any method may be employed, such as adding ε-caprolactone monomer to the high-melting crystalline segment.

The fatty acid amide compound (B), which is one of the components used in the polyester block copolymer composition of the present invention, is selected from the group of compounds represented by the following structural formula (I).

[0026]

Embedded image (Wherein R 1 and R 2 represent a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, and R 1 and R 2 may be the same group. Good, R3, R4
Represents a hydrocarbon group obtained by further removing one primary hydrogen from those hydrocarbon groups, and R3 and R4 may be the same group. The groups R1 and R2 in the structural formula (I) include a methyl group,
Saturation of ethyl, propyl, butyl, pentyl, hexyl, hepsyl, octyl, capryl, lauryl, undecanyl, myristyl, palmityl, heptadecanyl, stearyl, arachidyl, behenyl, etc. Aliphatic hydrocarbon group, palmitoleyl group,
Heptadecenyl group, oleyl group, eicosenyl group, ersyl group, linole group, linolenic group, unsaturated aliphatic hydrocarbon group such as cyclopentyl group, cyclopentenyl group,
Examples include alicyclic hydrocarbon groups such as cyclohexyl groups, and aromatic hydrocarbon groups such as phenyl groups, phenylpropane groups, phenylsulfone groups, benzyl groups, toluyl groups, xylyl groups, and naphthyl groups. R1 and R2 may be the same group. Examples of the groups R3 and R4 in the structural formula (I) include groups in which one terminal hydrogen is further removed from the above-described hydrocarbon groups exemplified as the groups R1 and R2. Of these, the groups R1 and R2 are a palmityl group, a stearyl group,
Those composed of a combination of a heptadecyl group, a palmitoleyl group, a heptadecyl group, an oleyl group, an eicosenyl group and the like are preferable. Further, the group R3 is a group in which one hydrogen is further removed from the terminal of the ethyl group, and the group R4 is n-
A group in which one primary hydrogen is further removed from the terminal of a butyl group or an n-octyl group is preferable.

In the polyester block copolymer composition of the present invention, these fatty acid amide compounds (B)
One kind or two or more kinds of compounds are combined, and 0.005 to 5 parts by weight, preferably 0.01 to 5 parts by weight are blended with respect to 100 parts by weight of the polyester block copolymer (A). If the amount of the fatty acid amide compound (B) is less than 0.005 parts by weight, the stick-slip inhibiting effect is not sufficiently maintained, and if it exceeds 5 parts by weight, poor compatibility with the polyester block copolymer during melting is caused. It becomes severe, and peeling or the like occurs on the surface of the molded product, thereby impairing mechanical properties and the like.

The compound (C), which is one of the components used in the polyester block copolymer composition of the present invention, comprises:
It is selected from compounds represented by the following structural formula (II).

[0029]

Embedded image (In the above formula, R5 is a group obtained by removing 2 hydrogen atoms from a hydrocarbon compound having 1 to 6 carbon atoms. X represents an integer of 1 to 1000.) As the compound represented by the above structural formula, poly (ethylene oxide) ) Glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (pentamethylene oxide) glycol, poly (hexamethylene oxide) glycol, and the like. Specific examples thereof include poly (tetramethylene oxide). Glycols are preferred.

X which is the number of repeating units in the above structural formula
Is an integer of 1 to 1000, but is preferably 10 to 500 in terms of availability from the market.

In the polyester block copolymer composition of the present invention, the compound (C) selected from these compounds may be used alone or in combination of two or more kinds thereof, based on 100 parts by weight of the polyester block copolymer. , 0.01 to 20 parts by weight, preferably 0.2 to 10 parts by weight
Mix by weight. If the amount is less than this, stick-slip cannot be effectively suppressed. On the other hand, if the amount is larger than the above range, the strength of the polyester block copolymer composition decreases, and molded products such as flexible boots formed from the composition are easily damaged, which is not preferable.

The method for producing the polyester block copolymer composition of the present invention is not particularly limited. For example, a polyester block copolymer, a fatty acid amide compound (B), a compound (C), if necessary, A method in which a raw material in which other additives such as carbon black are compounded together is supplied to a screw type extruder and melt-kneaded.

The polyester block copolymer composition of the present invention may contain a known antioxidant such as a hindered phenol, phosphite, thioether or aromatic amine as long as the object of the present invention is not impaired. , Benzophenone-based, benzotriazole-based, hindered amine-based light stabilizers, reinforcing agents such as glass fibers, flame retardants, and the like.

The polyester block copolymer composition of the present invention is formed into a molded product by injection molding, blow molding, extrusion molding, compression molding, etc., and is particularly excellent as a material for a flexible boot for a flexible joint formed by blow molding. ing.

These molded articles not only effectively suppress the surface stick and slip, but also can maintain their effects for a long time under any use conditions such as high temperature conditions. In addition, the inherent rubber elasticity, durability, and mechanical strength of the polyester block copolymer are not impaired.

[0036]

The polyester block copolymer composition of the present invention contains a compound (C) and a fatty acid amide compound (B) as a slidability improving agent.

The compound (C) is of the same type as the compound disclosed by the present inventors in Japanese Patent Application Laid-Open No. H11-130952, and uniformly oozes out on the surface of a molded article to effectively suppress stick-slip. I do. However, this compound (C)
Since the melting point of the molded article is generally 100 ° C. or less, when the molded article is subjected to friction in a high-temperature atmosphere, the molded article becomes the melting point or more and liquefies, so that it is easily wiped off.

However, in the polyester block copolymer composition of the present invention to which the fatty acid amide compound (B) is added together with the compound (C), the fatty acid amide compound (B)
And the compound (C) exudes to the surface of the molded article made of the polyester block copolymer. Surprisingly, the mixed precipitate of the compounds (B) and (C) is hardly wiped off from the surface by friction even in a state where the compound (C) is melted in a high-temperature atmosphere, and inhibits stick-slip for a long time. Lasting effect.

As described above, the polyester block copolymer composition of the present invention not only effectively suppresses stick-slip on the surface of a molded article made of the same, but also under any use conditions such as high temperature conditions. The effect can be maintained for a long time. Therefore, the composition is suitable for a flexible boot of a constant velocity joint for an automobile and the like.

[0040]

EXAMPLES The effects of the present invention will be described below with reference to examples. All percentages and parts in the examples are on a weight basis unless otherwise specified. The physical properties shown in the examples were measured as follows. Melting point: Using a differential scanning calorimeter (DSC-910, manufactured by Du Pont), the top temperature of the melting peak when heated at a rate of 10 ° C./min in a nitrogen gas atmosphere was measured. -Melt viscosity index (MFR value): ASTM D-1238
Was measured with a load of 2160 g.・ Hardness (Durometer D scale): ASTM D-
Measured according to 2240. Reference Example Production of polyester block copolymer (A-1) 302 parts of terephthalic acid, 327 of 1,4-butanediol
Parts and 216 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400 were charged into a reaction vessel equipped with a helical ribbon type stirring blade together with 0.15 part of titanium tetrabutoxide, and heated at 190 to 225 ° C. for 3 hours. The esterification reaction was performed while distilling the reaction water out of the system. Add "Irganox" 1010 (a hindered antioxidant manufactured by Ciba Geigy) to the reaction mixture.
After adding 75 parts, the temperature was raised to 245 ° C., and the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out for 2 hours and 45 minutes under the conditions. The obtained polymer was discharged into water in the form of a strand, and cut into pellets.

Polyester block copolymer (A-2)
Preparation of 245 parts of dimethyl terephthalate, 171 parts of 1,4-butanediol and 239 parts of poly (tetramethylene oxide) glycol (number average molecular weight: about 1400), together with 0.15 part of titanium tetrabutoxide in a helical ribbon form The reaction vessel was equipped with a stirring blade and heated at 210 ° C. for 2 hours to distill 95% of the theoretical methanol amount out of the system. Add "Irganox" 101 to the reaction mixture.
After adding 0.75 parts of 0, the temperature was raised to 245 ° C., and the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out for 2 hours and 20 minutes under the conditions. The obtained polymer was discharged into water in the form of a strand, and cut into pellets.

Table 1 shows the composition and physical properties of A-1 and A-2. In the table, the type of the low-melting polymer segment is P
TMG stands for poly (tetramethylene oxide) glycol, and the numbers indicate the number average molecular weight.

[0043]

[Table 1] Table 2 shows the fatty acid amide compounds (B) constituting the compositions of Examples and Comparative Examples, and Table 3 shows the compounds (C).

[0044]

[Table 2]

[0045]

[Table 3] Examples 1-4 Polyester block copolymers (A-1), (A-2)
To 100 parts by weight of each, a fatty acid amide compound (B) shown in Table 2 and a compound (C) shown in Table 3 were combined and mixed at a ratio shown in Table 4 with a V-blender to obtain 45 m
The mixture was melt-kneaded at a temperature shown in Table 4 using a twin-screw extruder having an m screw and pelletized.

[0046]

[Table 4] With respect to the physical properties of the obtained polyester block copolymer composition, the following evaluation was performed using an injection molded piece. -Tensile properties: Measured on the No. 2 test piece according to JIS K7113. Further, these polyester block copolymer compositions were prepared using an injection molding machine to obtain a diameter of 100 m.
A disk test piece having a thickness of 3 mm and a thickness of 3 mm was molded, and the following stick-slip test was performed. Table 5 shows the results. Stick-slip test: A single small-diameter disk having a diameter of 50 mm is punched out from a set of disk test pieces which are allowed to stand at 20 ° C. for 3 days after injection molding. A disc test piece having a diameter of 100 mm is set on a Taber abrasion tester, and a disc test piece having a diameter of 50 mm is set on a wear wheel rotating shaft of the tester. A 2631 g load was applied to the rotating shaft of the abrasion wheel, and a Taber abrasion test was performed with the surface of a disk test piece having a diameter of 100 mm wet with water. The tester measured the noise after 100, 500, and 1000 rotations. I do. It is determined that stick-slip occurs when the noise increases with respect to the background noise (about 60 dB). The measurement is performed at an ambient temperature of 25 ° C. and 100 ° C. During the test, water is dropped at any time so that the surface of the disc test piece having a diameter of 100 mm is wet.

[0047]

[Table 5] Comparative Examples 1-4 Polyester block copolymer (A-1), (A-2)
100 parts by weight of the fatty acid amide compound (B) shown in Table 2 and / or the compound (C) shown in Table 3 were mixed at a ratio shown in Table 4 with a V-blender, and a twin screw extruder having a 45 mm screw was used. Was melt-kneaded at the temperature shown in Table 4 and pelletized. The same evaluation as in the example was performed using these pellets. Table 5 shows the results.

Examples 1 to 4 in Table 5 and Reference Examples 1 and 2
As shown in the comparison, the polyester block copolymer composition of the present invention has no extreme decrease in tensile properties, and is also capable of suppressing stick-slip for a long time regardless of the ambient temperature in the stick-slip test. I have.

On the other hand, in the polyester block copolymer composition containing only the fatty acid amide compound (B) as in Comparative Example 1, stick-slip in a high-temperature atmosphere cannot be suppressed for a long time. When the amounts of the fatty acid amide compound (B) and the compound (C) are small as in Comparative Example 2, stick-slip cannot be suppressed for a long time in a room temperature atmosphere, and stick-slip cannot be suppressed in a high temperature atmosphere.

On the other hand, when the addition amount of the compound (C) is too large as in Comparative Example 3, stick-slip can be suppressed for a long time, but a mechanical strength such as tensile strength is apparent as compared with Reference Example 2. Remarkable decrease in mechanical strength. When the amount of the fatty acid amide compound (B) added is too large as in Comparative Example 4, delamination occurs on the surface of the molded product, which poses a practical problem. Example 5 and Comparative Example 5 Polyester Block Copolymer 10 of Reference Example (A-2)
For 0 parts, 0.5 part of "Irganox" 1010 (a hindered phenolic antioxidant manufactured by Ciba-Geigy),
0.3 parts of diphenylmethane diisocyanate, 1.0 part of carbon black, and the fatty acid amide compound (B
After mixing 1.0 part and 1.5 parts of the compound (C) shown in Table 3 in a Henschel mixer, the mixture was melt-kneaded at 240 ° C. using a twin-screw extruder having a screw of 45 mm, and discharged. The polymer thus obtained was pelletized to obtain a polyester block copolymer composition of Example 5.

As in Example 5, 0.5 parts of "Irganox" 1010 (a hindered phenolic antioxidant manufactured by Ciba-Geigy) and 100 parts by weight of diphenylmethane were added to 100 parts by weight of the polyester block copolymer (A-2). After mixing 0.3 part of diisocyanate, 1.0 part of carbon black and 1.0 part of the fatty acid amide compound (B) shown in Table 2 in a Henschel mixer, using a twin screw extruder having a screw of 45 mm, Melt kneading was performed at 240 ° C. to obtain a polyester block copolymer composition of Comparative Example 5.

After the obtained polyester block copolymer composition was dried with hot air at 80 ° C. for 5 hours, the cylinder temperature was 230 ° C. and the nozzle temperature was 230 ° C. using a press blow molding machine (SBE50 / 140, manufactured by Osberger). A flexible boot for a constant velocity joint was molded at a molding temperature of 30 ° C. and a mold temperature of 30 ° C.

After the flexible boot was allowed to stand at 20 ° C. for 24 hours or more after molding, the flexible boot was mounted on a constant velocity joint, and the operating noise at the time of driving the joint was measured using a sound level meter. Measurements were taken immediately after the flexible boot was attached and at an ambient temperature of 10
0 ° C, joint rotation speed 100rpm, operating angle 10 °
３８ → 38 ° was oscillated in one cycle of 10 seconds and rotated for 48 hours. As the test conditions, the following operating noise test conditions were employed in a state where water was present on the surface of the flexible boot.

Operating noise test conditions: Test temperature: 23 ° C. Test rotation speed: 200 rpm Operating angle: 40 ° Distance to sound level meter: 20 cm When the operating angle of the joint is 0 ° and the bellows of the flexible boots do not contact each other, the joint The operating noise during driving is about 60 dB.

Table 6 shows the physical properties of the polyester block copolymer compositions of Example 5 and Comparative Example 5, and the results of the operation noise test of the flexible boot molded using the same.

[0056]

[Table 6] The flexible boot molded using the polyester block copolymer composition of the present invention in Example 5 did not generate abnormal sliding noise in the test immediately after the constant velocity joint was mounted and after the rotation in a high-temperature atmosphere. .

On the other hand, the flexible boot molded using the polyester block copolymer composition of Comparative Example 5
In the test immediately after mounting on the constant velocity joint, no abnormal sliding noise was generated. However, in the test after rotating for 48 hours in a high temperature atmosphere, abnormal sliding noise was generated. Therefore, the polyester block copolymer composition of the present invention,
Even when used in a high temperature atmosphere,
Sliding noise due to slip can be suppressed.

[0058]

According to the present invention, a polyester block copolymer composition having good sliding properties can be obtained by melt-mixing a specific compound with the polyester block copolymer. In particular, the polyester block copolymer composition of the present invention can provide a molded article which does not cause stick-slip for a long time under any use conditions such as a high temperature atmosphere.

Further, the flexible boot for a universal joint made of the polyester block copolymer composition of the present invention does not generate sliding noise due to stick-slip for a long time under any use conditions such as a high temperature atmosphere.

Continuation of the front page (72) Inventor Yoko Furuta 19804, Kita-ku, Minato-ku, Nagoya-shi, Aichi Prefecture No. 1919 Toray Dupont Co., Ltd. Nagoya Office F-term (reference) 4J002 CF031 CF101 CF171 CH022 CH032 EC047 EP036 FD010 FD040 FD070 GN00

Claims (12)

[Claims] 1. A high melting crystalline polymer segment (a) mainly composed of a crystalline aromatic polyester unit, and a low melting polymer segment (b) mainly composed of an aliphatic polyether unit and / or an aliphatic polyester unit. In a polyester block copolymer (A) having (A) as a main constituent, one or more kinds of fatty acid amide compounds (B) represented by the following structural formula (I), and further represented by the following structural formula (II) In the polyester block copolymer composition obtained by mixing one or more kinds of the compound (C) to be obtained, the compounding amount of the fatty acid amide compound (B) is based on 100 parts by weight of the polyester block copolymer (A). A polyester block copolymer composition comprising 0.005 to 5 parts by weight and a compounding amount of the compound (C) of 0.01 to 20 parts by weight. Embedded image (Wherein R 1 and R 2 represent a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, and R 1 and R 2 may be the same group. Good, R3, R4
Represents a hydrocarbon group obtained by further removing one primary hydrogen from those hydrocarbon groups, and R3 and R4 may be the same group. ) (In the above formula, R5 is a group obtained by removing 2 hydrogen atoms from a hydrocarbon compound having 1 to 6 carbon atoms. X represents an integer of 1 to 1000.) 2. The group R3 in the structural formula (I) of the fatty acid amide compound (B) is a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 1 to 4 carbon atoms. The polyester block copolymer composition according to claim 1. 3. The fatty acid amide compound (B) wherein the groups R1, R2 and R4 in the structural formula (I) have a saturated aliphatic hydrocarbon group having 2 or more carbon atoms, an unsaturated aliphatic hydrocarbon group, an alicyclic hydrocarbon group. 3. The polyester block copolymer composition according to claim 1, which is a hydrogen group or an aromatic hydrocarbon group. 4. The polyester block copolymer composition according to claim 1, wherein the group R3 in the structural formula (I) of the fatty acid amide compound (B) is a group obtained by removing one hydrogen from ethylene. 5. The fatty acid amide compound (B), wherein the groups R1 and R2 in the structural formula (I) are at least one group selected from a stearyl group, a palmityl group and an oleyl group. Polyester block copolymer composition. 6. The polyester block according to claim 1, wherein the group R4 in the structural formula (I) of the fatty acid amide compound (B) is a group obtained by removing one primary hydrogen from the terminal of an n-octyl group. Polymer composition. 7. The compound C represented by the structural formula (II) is poly (tetramethylene oxide) glycol or a mixture of poly (alkylene oxide) glycols including poly (tetramethylene oxide) glycol.
7. The polyester block copolymer composition according to any one of claims 6 to 6. 8. A high melting crystalline polymer segment (a)
The polyester block copolymer composition according to any one of claims 1 to 7, wherein the polyester block copolymer mainly comprises polybutylene terephthalate units. 9. The polyester block copolymer composition according to claim 1, wherein the low melting point polymer segment (b) is composed of poly (tetramethylene oxide) glycol units. 10. A polyester block copolymer (A)
The copolymerization amount of the low melting polymer segment (b) is 1
The polyester block copolymer composition according to any one of claims 1 to 9, which is 0 to 80% by weight. 11. The method according to claim 1, which is used for blow molding.
10. The polyester block copolymer composition according to any one of 10. 12. The polyester block copolymer composition according to claim 1, which is used for forming a flexible boot for a universal joint having a shape in which a large diameter portion and a small diameter portion are connected by a bellows portion.