JPH09194704A - Resin composition for constant-velocity joint boot for automobile and constant-velocity joint boot for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant-velocity joint boot for automobiles, capable of carrying out assembling operation to a joint part in an automobile manufacturing process, etc., extremely readily in a short time, much higher in durability in practical use after assembly due to excellent wear resistance and to obtain a resin composition having both flexibility and wear resistance suitable for the joint boot. SOLUTION: This polyester elastomer resin composition is obtained by blending 100 pts.wt. of a polyester (A) with 0.05-7.0 pts.wt. of an organic polyisocyanate (B) and 0.1-5.0 pts.wt. of a silicone compound (C) in a melt state and has 34-44 surface hardness (shore hardness D). The composition is molded into a fixed shape by a blow molding to give the objective molding.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention uses a polyester elastomer (hereinafter abbreviated as TPEE) and has a resin composition for automobile constant velocity joint boots which is modified to have a higher melt viscosity and is excellent in wear resistance, mechanical properties and flexibility. The present invention relates to a molded article for an automobile constant velocity joint boot obtained by blow molding the composition and the composition.

[0002]

2. Description of the Related Art Automobile constant velocity joint boots are used for front and rear accelerators, and rotate while repeating crossing and sliding movements such as steering operation, bounding and the like. For this reason, the bellows portion repeats expansion and contraction and bending. The essential function of this automobile constant velocity joint boot is to protect the joint, which is to prevent the intrusion of water, dust and the like from the outside and to retain the grease inside. Properties required of the boot from the usage environment conditions include flexibility, bending fatigue resistance, abrasion resistance, water resistance, puncture resistance, cold resistance, weather resistance, and grease resistance.

Conventionally, rubber materials have been generally used to satisfy these characteristics. In particular, chloroprene rubber which is excellent in bending fatigue resistance and weather resistance and has other characteristics in a well-balanced manner is preferably used. But,
When chloroprene rubber is used for a long period of time, it often breaks due to stepping stones and ozone cracks, making it difficult to respond to recent vehicle needs such as improved reliability, longer life, higher speed, and lighter weight. ing.

[0004] For these reasons, TPE which is lightweight, has high rigidity, and is excellent in fatigue resistance and cold resistance as a material replacing rubber.
E has been considered. As a result, TP has been
EE automobile constant velocity joint boots have been employed.

[0005]

However, the conventional TPEE automobile constant velocity joint boot has a problem that it is difficult to assemble in a manufacturing process because it is harder than a rubber boot. These are considered to be countermeasures if the hardness of the TPEE automobile constant velocity joint boots is reduced. However, if the hardness is reduced, the durability (wear resistance) tends to be deteriorated. ) Is 45
The following TPEE automobile constant velocity joint boots having excellent durability have not been found.

[0006]

[Means for Solving the Problems] As a result of earnest research to achieve the above-mentioned object, TPEE (A), an organic polyisocyanate compound (B) and a silicone compound (C) were melt mixed at a specific weight ratio. The obtained thermoplastic resin composition has a high melt viscosity and a specific hardness, and is excellent in abrasion resistance and flexibility. In addition, it is obtained by blow molding it into a predetermined shape. We have found that the constant velocity joint boot molded product is flexible, easy to assemble in the manufacturing process, and excellent in durability, and completed the present invention.

That is, the present invention is based on 100 parts by weight of the polyester elastomer (A), 0.05 to 7.0 parts by weight of the organic polyisocyanate compound (B) and 0.1 to 5.0 parts by weight of the silicone compound (C). A surface hardness (Shore D) obtained by melt-mixing and is 34 to 44 and a resin composition for automobile constant velocity joint boots, and an automobile constant velocity joint boot molded product obtained by using the resin composition, Specific hardness TPE modified to high melt viscosity
It is intended to provide a resin composition for an automobile constant velocity joint boot, which contains E and is excellent in wear resistance and flexibility, and an automobile constant velocity joint boot molded product obtained by blow molding the same.

As the TPEE (A) in the present invention, known and commonly used polyester elastomers can be used. This TPE
As E (A), for example, those obtained by reacting low molecular weight diols, dicarboxylic acids, aliphatic polyethers and / or aliphatic polyesters, or their ester-forming derivatives as essential components can be used.

As TPEE (A), alkylene glycol, terephthalic acid and / or its ester-forming derivative alkyl ester, and poly (oxyalkylene)
Alkylene terephthalate-based TPEE obtained by reacting glycol or their ester-forming derivatives is preferred, and tetramethylene terephthalate-based TPEE is particularly preferred because of its excellent flexibility and elastic recovery.

As the TPEE (A), for example, a polyester elastomer having a rebound resilience of 55 to 85% according to the measurement method JIS K-6301 is preferable.

Further, as TPEE (A), those having a surface hardness (Shore D) of 30 to 50 are usually used, and those having a hardness of 33 to 46 are particularly preferable in terms of flexibility.

TPEE (A) is generally composed of a hard segment and a soft segment when viewed from the molecular structure. The hard segment is a unit composed of a low molecular weight diol, a dicarboxylic acid and / or an alkyl ester thereof, and the soft segment is a unit composed of an aliphatic polyether and / or an aliphatic polyester and a dicarboxylic acid and / or an alkyl ester thereof. Consists of

As the TPEE (A) of the present invention, those in which the ratio of the soft segment to the hard segment in the molecular structure is the former / the latter (weight ratio) = 40/60 to 75/25 are preferable.

Examples of the low molecular weight diol for obtaining TPEE (A) of the present invention include ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-dimethyl-trimethylene glycol, hexamethylene glycol, decamethylene. Examples include alkylene glycols such as glycol, p-xylylene glycol, and cyclohexanedimethanol.

Examples of the dicarboxylic acid and / or alkyl ester include terephthalic acid, isophthalic acid,
Aromatic dicarboxylic acids such as 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, bis (p-carboxyphenyl) methane, and 4,4-sulfonyldibenzoic acid; Examples thereof include aliphatic dicarboxylic acids and dialkyl esters thereof.

Examples of the aliphatic polyether and / or aliphatic polyester include poly (oxyalkylene) glycols such as poly (oxyethylene) glycol, poly (oxypropylene) glycol and poly (oxytetramethylene) glycol; A mixture or copolymer of alkylene ether) glycols, poly-ε caprolactone, a polyester obtained from an aliphatic dicarboxylic acid having 2 to 12 carbon atoms and an aliphatic glycol having 2 to 10 carbon atoms, for example, polyethylene adipate, polytetramethylene adipate, Polyethylene sebacate, polyneopentyl sebacate, polytetramethylene dodecane, polytetramethylene acetate, polyhexamethylene acetate, etc .; Polyester polyether copolymer which is a combination of ether and the like.

In obtaining the TPEE (A) of the present invention, if necessary, p-oxybenzoic acid,
A small amount of p- (β-hydroxyethoxy) benzoic acid or the like may be used in combination as a raw material component.

TPEE (A) in the present invention can be obtained by a known and commonly used polycondensation reaction.
Is, for example, terephthalic acid or dimethyl terephthalate, 1,
It can be produced by reacting 4-butanediol and poly (oxytetramethylene) glycol as essential components.

The molar ratio is from 0.7 to 1.5 mol of dicarboxylic acid or its ester-forming derivative per 1 mol of the total of the diol and glycol. The molar ratio of the diol to the glycol is the diol / the glycol = 98/3 to 55/45 (mol%), preferably 95/5 to 60/40 (mol%).

At this time, these may be reacted simultaneously, or terephthalic acid or dimethyl terephthalate is reacted with 1,4-butanediol to obtain a prepolymer, which is then poly (oxytetramethylene). ) Glycol may be reacted.

As TPEE (A), a pre-polymer having a hard segment formed by reacting terephthalic acid or an alkyl ester prepared in advance with 1,4-butanediol, terephthalic acid or an alkyl ester thereof and poly (oxytetramethylene) A) a modified polyetherester block copolymer or a modified polyesterester block copolymer obtained by reacting a soft segment-forming prepolymer obtained by reacting a glycol and / or an aliphatic polyester with an organic polyisocyanate compound (B) described below. TPEE can also be used.

It is preferable that TPEE (A) is reacted with an organic polyisocyanate compound (B) described later to have a higher molecular weight. For this purpose, TPEE having an active hydrogen atom capable of reacting with an isocyanate group is preferably used. . Examples of the active hydrogen atom that can react with an isocyanate group include a hydroxyl group and a carboxyl group.

The TPEE having an active hydrogen atom capable of reacting with the isocyanate group is used to adjust the functional group equivalent ratio (molar ratio) of the carboxylic acid and the hydroxyl group-containing compound in consideration of the reaction rate in the reaction for obtaining the TPEE. Can be obtained.

Theoretically, under the reaction conditions in which the carboxyl group is excessive, a TPEE having only a carboxyl group as an active hydrogen atom is obtained. On the other hand, in the reaction condition in which the hydroxyl group is excessive, a TPEE having only a hydroxyl group as the active hydrogen atom is obtained.
Which, under equivalent reaction conditions, have a TPE having both carboxyl and hydroxyl groups as active hydrogen atoms.
E is obtained. The presence of a carboxyl group and a hydroxyl group can be determined by, for example, an acid value and a hydroxyl value in this order.

The composition of the present invention is obtained by melt-mixing TPEE (A), an organic polyisocyanate compound (B) and a silicone compound (C) as essential components.

TPEE (A), substantially the organic polyisocyanate compound (B), and the silicone compound (C)
Only these may be melt mixed, or if necessary, other components may be used together and melt mixed.

In the present invention, TPEE (A) is preferably selected so that it reacts by melt mixing. still,
As TPEE (A), it is preferable to use TPEE having an active hydrogen atom capable of reacting with an isocyanate group.

In the present invention, TPEE (A) is TPEE having at least a hydroxyl group, and among them, a hydroxyl value of 0.
It is preferable to use one having an amount of 5 to 4.0 mg (KOH) / g.

The organic polyisocyanate compound (B) used in the present invention is a compound having at least two or more isocyanate groups in an aliphatic or aromatic compound, and any known and commonly used one can be used. Further, a masked organic polyisocyanate compound can also be used.

As the organic polyisocyanate compound (B), any of known and commonly used compounds can be used. For example, toluene-2,4-diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1, 3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate-diphenyl ether, methylene diisocyanate, polymethylene polyphenylene polyisocyanate, 4,4-methylene bis ( (Phenylisocyanate), 2,4-tolylene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, 1,4-tetramethylene diisocyanate, 1,6
-Hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, 4,4
-Methylenebis (cyclohexyl isocyanate) and the like. The masked organic polyisocyanate compound is obtained by reacting the organic polyisocyanate compound with a masking agent in a solvent or in a molten state by heating. Examples of the masking agent include alcohols, phenols, alkylphenols, ε-caprolactam, methyl ethyl ketoxime and the like.

As the organic polyisocyanate compound (B) used at the time of melt mixing, 4,4-methylenebis (phenylisocyanate) is preferable because of its high thickening effect.

The larger the amount of the organic polyisocyanate compound (B) used within the range specified in the present invention, the higher the melt viscosity.

The silicone compound (C) used in the present invention is a silicone oil having a siloxane bond as a skeleton, various polymerization degrees, and optionally various organic groups in the side chain. Examples of the silicone compound (C) include those represented by the molecular structural formula (1).

[0034]

Embedded image

[In the formula, R may be the same or different, a methyl group, a phenyl group or a hydrogen atom, and n is an integer]

Specifically, in the above-mentioned molecular structural formula (1), dimethyl silicone oil in which R is all a methyl group compound, phenylmethyl silicone oil in which a part of the methyl group is changed to a phenyl group, and R is 1 One example is a methyl hydrogen silicone oil in which one is a methyl group and the other one is a compound having a hydrogen atom.

In the present invention, a silicone oil having an arbitrary viscosity in which the degree of polymerization n is adjusted can be used, but among them, a dimethyl silicone oil having a viscosity of 1000 to 100,000 centistokes (CS) at a measurement temperature of 23 ° C. is preferable.

The larger the amount of the silicone compound (C) used within the range specified in the present invention, the better the abrasion resistance.

The resin composition for automobile constant velocity joint boots of the present invention contains the above-mentioned TPEE (A), organic polyisocyanate compound (B) and silicone compound (C) as essential components for obtaining better moldability. In order to achieve high melt viscosity (higher molecular weight), they are melt mixed at a predetermined weight ratio.

In order to obtain a molded article for an automobile uniform velocity boot, a resin composition is prepared so that the impact resilience after melt mixing is 60 to 80%.

By this melt mixing, the TPEE used
(A) is made to have a high molecular weight by the organic polyisocyanate compound (B) and thickens. The amounts of TPEE (A), organic polyisocyanate compound (B) and silicone compound (C) used are adjusted so that the finally obtained polyester elastomer resin composition has a surface hardness of 34 to 44.

The amount of the organic polyisocyanate compound (B) used is 0.05 to 7.0 parts by weight, preferably 0.10 to 100 parts by weight, based on 100 parts by weight of TPEE (A).
5.0 parts by weight. Similarly, the silicone compound (C) is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of TPEE (A).
Parts by weight, preferably 0.3 to 4.0 parts by weight. The composition is prepared so that the rebound resilience falls within the above range.

The mixing method is not particularly limited, but granular,
The above-mentioned (A) to (C) in the form of powder, flakes, liquid or the like is melt-mixed as an essential component. For example, there are the following methods. A masterbatch of (B) and / or (C) prepared in advance, in which (A) to (C) are melt mixed at the same time;
Melt mix with TPEE (A). When these are melt-mixed, the viscosity sharply increases. Therefore, a melt extrusion kneader such as an extruder is usually used.

The temperature and the mixing time during melt mixing are not particularly limited, and are adjusted according to the melt mixing method and the desired physical properties. Usually, it may be performed at a temperature equal to or higher than the melting temperature of TPEE (A).
The range up to 0 ° C is preferred. The mixing time may be performed until the viscosity is saturated and constant, but is usually about 10 seconds to 120 minutes.

The resin composition for automobile constant velocity joint boots of the present invention has sufficiently excellent characteristics even if it comprises only the above (A) to (C), but if necessary, it is inorganic and / or organic. Fillers and additives can be added. In this case, for example, release agents, coupling agents, colorants, lubricants, heat resistance stabilizers, weather resistance stabilizers, foaming agents, rust inhibitors, flame retardants, hydrolysis inhibitors, lubricants, colorants, fillers. ,
Reinforcing materials and the like may be added.

Furthermore, if necessary, other polyester elastomers or other thermoplastic resins such as thermoplastic polyurethane resins, olefin elastomers, styrene elastomers, polyamide elastomers are added within a range that does not impair the effects of the present invention. You can also do it.

The surface hardness thus obtained is 34 to 44.
The polyester elastomer resin composition of (1) is molded into a desired shape and used as an automobile constant velocity joint boot molded article.

The automobile constant velocity joint boot molded article of the present invention may be composed of the resin composition for a constant velocity joint boot of the present invention alone, or a composite of reinforcing materials such as plastic and metal. But good. The shape is not particularly limited, but a shape that can flexibly respond to deformation such as a bellows shape or a bell shape in order to follow swinging, sliding, reciprocating motion, and the like is preferable.

The resin composition for automobile constant velocity joint boots of the present invention is preferably formed by blow molding according to its shape. Examples of the blow molding method include a method in which a sufficiently dried resin composition of the present invention having a hardness of 34 to 44 is plasticized in a heating cylinder of a blow molding machine and cooled and solidified in a mold to obtain a predetermined molded product. To be

Usually, in carrying out molding, each condition such as cylinder temperature, extrusion speed, parison wall thickness, blowing time, mold temperature, etc. is appropriately selected, and molding is carried out under good conditions.

[0051]

Next, preferred embodiments of the present invention will be specifically described. The soft segment / the hard segment (weight ratio) = 40/60 to 75/2
5, poly (oxytetramethylene) glycol having a surface hardness (Shore D) of 33 to 46 and an average molecular weight of 800 to 3000, having both a carboxyl group and a hydroxyl group, and a hydroxyl value of 0.5 to 4. 0mg (KOH) /
100 g by weight of tetramethylene terephthalate-based TPEE (A) having an acid value of 0.5 to 3.0 mg (KOH) / g and a rebound resilience of 55 to 80%, and adding 4,4-methylenebis (phenylisocyanate) to 0.1 part by weight. 10-5 parts by weight, 50
0.3 to 4.0 parts by weight of dimethyl silicone oil having a viscosity of 100 to 60,000 centistokes is uniformly mixed in advance,
Melt mix at 190-250 ° C.

In this way, the impact resilience of 60-80%,
Surface hardness (Shore D) in the range of 34-44,
A resin composition for automotive constant velocity joint boots having a melt viscosity at 30 ° C. of 7,500 to 25,000 poise and a tensile strength of 18 to 30 Mpa is obtained.

A cylinder temperature of 210 is applied to the resin composition.
~ 250 ° C, extrusion speed 5-15 mm / sec, parison wall thickness 2-5 mm, blowing time 1-10 sec, mold temperature 2
An automobile constant velocity joint boot molded article can be obtained by molding with a blow molding machine under the condition of 0 to 40 ° C.

The preferred molded article thus obtained is not only excellent in flexibility and abrasion resistance as the effects of the present invention, but also has secondary effects such as bending fatigue resistance, water resistance, and It is also extremely useful in practical use because it is excellent in puncture resistance, cold resistance, weather resistance, grease resistance, ozone resistance and mechanical properties.

[0055]

The present invention will be further described with reference to the following examples. The melt viscosity, abrasion resistance, hardness, tensile strength and tensile elongation in the examples were measured according to the following procedures. Parts in Examples are parts by weight.

(1) Melt viscosity A pellet obtained by melt mixing was measured using a capillary rheometer. Temperature: 230 ° C. Die: 0.5 mm × 5.0 mm

(2) Hardness Shore D was measured according to ASTM D-2240. The measurement temperature was 23 ° C. (3) Tensile strength, tensile elongation Measured according to JIS K-6301. Measurement temperature is 23
° C. (4) Rebound resilience Measured according to JIS K-6301. Measurement temperature is 23
° C.

(5) Abrasion resistance of automobile constant velocity joint boot molded product A molded product obtained by using a blow molding machine was subjected to a temperature of 25 ± 3.
After standing in an atmosphere at 40 ° C. and a humidity of 40 to 50% for 24 hours or more, a function evaluation test as an automobile constant velocity joint boot is performed under the following conditions, and the wear depth of the product surface (contact portion) after 300 hours is measured. did.

Measurement conditions Rotational speed: 600 rpm Swing angle: 25-40 ° Swing cycle: 30 cycles / minute Atmosphere temperature: 23 ° C.

[Production Example of TPEE (A ₁ )] 22.1 kg of dimethyl terephthalate and 1,4-butanediol 1
0.8 kg and a polyoxytetramethylene glycol having a molecular weight of about 1000 (PTMG-1000) 27.5 k
g and subjected to transesterification to remove methanol, and then heated to a temperature of 2 in the presence of tetrabutyl titanate (catalyst).
A polycondensation reaction was performed at 45 ° C. for 3 hours to obtain TPEE.
This TPEE has a soft group / hard segment (weight ratio) = 62/38 and has both a carboxyl group and a hydroxyl group, and a hydroxyl value of 1.97 mg (KO).
H) / g and an acid value of 1.19 mg (KOH) / g.

Intrinsic viscosity and melt viscosity of the obtained TPEE pellet and a molded sheet (2 mm thickness) molded by injection molding
Table 1 shows the surface hardness (Shore D) and the rebound resilience of the sample. Hardness is one measure of flexibility.

[0062]

[Table 1]

Examples 1 to 6 The above-obtained TPEE-A ₁ is uniformly mixed in advance with the compounding composition shown in Table 2. 40m set at 240 ° C
After melt-kneading with an mφ single screw extruder, the mixture was drawn out as a strand, cooled, and cut with a pelletizer to obtain a pellet.

These pellets were molded by an in-line screw type injection molding machine at a cylinder temperature of 250 ° C., a mold temperature of 40 ° C., and an injection speed of medium speed to obtain a molded product for evaluation. The intrinsic viscosity, melt viscosity, and surface hardness (Shore D), rebound resilience, tensile strength, and tensile elongation of a molded sheet (2 mm thick) formed by injection molding were measured in the same manner as described above. Table 2 shows the results. These molded articles had good appearance gloss.

Further, using each of the compounded compositions shown in Table 2, an automobile constant velocity joint boot molded article was formed by blow molding under the following conditions, and the abrasion resistance was evaluated. Table 2 shows the results. The shape of the molded product was as shown in FIG.

Blow molding conditions Extrusion speed: 220 ° C. Extrusion speed: 10 mm / sec Parison wall thickness: 2-5 mm Blowing time: 1-10 sec Mold temperature: 20-40 ° C.

[0067]

[Table 2]

In the table, MDI represents 4,4-methylene bis (phenylisocyanate), and TDI represents 2,4-tolylenediisocyanate.

Comparative Example 1 In the same manner as shown in Examples 1 to 6, the compounding compositions shown in Table 3 were evaluated. Table 3 shows the results.

[0070]

[Table 3]

As can be seen from the comparison between Example 2 and Comparative Examples 1 and 2, the wear resistance of the joint boots obtained from the compositions of Examples was determined by using the conventional TPEE as the silicone compound alone or the organic polyisocyanate compound. It is exceptionally unpredictable from each joint boot obtained from each composition melt-blended using only.

As can be seen from the comparison between Example 2 and Comparative Examples 1 and 2, the automobile constant velocity joint boot obtained by melt mixing the organic polyisocyanate compound and the silicone compound has good flexibility and wear resistance. In addition, it is extremely easy to assemble during the manufacturing process, and also has excellent durability during actual use after assembly.

[0073]

INDUSTRIAL APPLICABILITY The resin composition for automobile constant velocity joint boots of the present invention comprises modifying TPEE (A) with a specific amount of an organic polyisocyanate compound (B) and using a specific amount of a silicone compound (C) in combination. Since it is contained therein to form a resin composition having a specific hardness range, a particularly remarkable effect of obtaining a composition having both flexibility and abrasion resistance is exhibited.

Moreover, an automobile constant velocity joint boot molded article obtained by blow molding of the above composition has good flexibility, so that workability is poor when it is hard, so that assembly work to a joint portion in an automobile manufacturing process is difficult. It is extremely easy and can be done in a shorter time, and due to its good wear resistance, it has a particularly remarkable effect that it can have higher durability during actual use after assembly.

[Brief description of the drawings]

FIG. 1 is a half sectional view of an automotive constant velocity joint boot made of a thermoplastic polyester elastomer resin composition obtained in an example of the present invention.

[Explanation of symbols]

 1 Constant velocity joint boot 2 Small diameter ring part 3 Bellows part 4 Large diameter ring part 5 Shaft 6 Universal joint 7 Small diameter band 8 Large diameter band

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Taguchi 866-193 Natural Field, Hannan-shi, Osaka (72) Inventor Kaoru Mori 2-34-34, Nishirodai, Sakai-shi, Osaka 3-3-31 Higashisukematsu-cho, Izumiotsu-shi Kimatsu Ryo 403

Claims (9)

[Claims] An organic polyisocyanate compound (B) based on 100 parts by weight of a polyester elastomer (A)
0.05 to 7.0 parts by weight of silicone compound (C) 0.
A resin composition for automobile constant velocity joint boots, which has a surface hardness (Shore D) of 34 to 44 obtained by melt mixing 1 to 5.0 parts by weight. 2. The resin composition for an automobile constant velocity joint boot according to claim 1, wherein the polyester elastomer (A) is a polyester elastomer containing an active hydrogen atom capable of reacting with an isocyanate group. 3. The resin composition according to claim 1, wherein the polyester elastomer (A) is a polyester elastomer having a rebound resilience of 55 to 85%. 4. The polyester elastomer (A) is a polyester elastomer obtained by reacting terephthalic acid or an ester-forming derivative thereof, 1,4-butanediol and poly (oxytetramethylene) glycol as essential components. A resin composition for an automobile constant velocity joint boot as described above. 5. The resin composition for automobile constant velocity joint boots according to claim 1, wherein the rebound resilience after melt mixing is 60 to 80%. 6. The resin composition according to claim 1, wherein the polyester elastomer (A) has a surface hardness (Shore D) of 30 to 50. 7. The resin composition according to claim 1, wherein the organic polyisocyanate compound (B) is 4,4-methylenebis (phenylisocyanate). 8. The resin composition according to claim 1, wherein the silicone compound (C) is dimethyl silicone oil. 9. An organic polyisocyanate compound (B) based on 100 parts by weight of a polyester elastomer (A).
0.05 to 7.0 parts by weight of silicone compound (C) 0.
An automotive constant velocity joint boot molded article obtained by blow molding a resin composition having a surface hardness (Shore D) of 34 to 44 obtained by melt mixing 1 to 5.0 parts by weight.