JP2919892B2 - Vibration damping polyester resin composition and molded article thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibration-damping resin composition having excellent vibration damping properties and a vibration-damping component obtained by molding the same.

[Conventional technology and its problems]

In recent years, attention has been paid to measures against vibration sources of various devices, and materials having vibration suppression (vibration suppression) performance have been required. In particular, it is often desired that mechanical parts for AV (audiovisual) such as CDs, parts for speakers, and body parts around an engine of an automobile do not sustain vibration and that vibration is difficult to propagate.

Conventionally, a composite metal plate for vibration damping has been frequently used as such a vibration damping means. This is to absorb and attenuate vibration by using an elastic polymer for an intermediate layer of a metal plate, and such a composite metal plate is used in a form surrounding a vibration source such as an engine or a motor. However,
Such a vibration-damping composite metal plate is complicated to process and very difficult to apply to parts having a complicated shape.

From this point of view, it is preferable to manufacture the above parts with a thermoplastic resin that can efficiently form parts with complicated shapes by injection molding, but in particular, it has a vibration suppression function and also has other general physical properties Resin has not been developed, and at present, some measures have been taken, such as simply using a resin having rigidity or specific gravity, and taking into account dimensions in order to compensate for defects in the materials used.

Under such circumstances, it is extremely useful in practice to impart a vibration damping function to a thermoplastic polyester resin having good general physical properties as an injection molded part. For example, polyalkylene terephthalate resin and the like are excellent in mechanical properties, electrical properties, and other physical and chemical properties.
Since the degree of improvement in mechanical properties due to the addition of carbon fiber is large, and the workability is good, it is used as a engineering plastic in a wide range of applications such as automobiles, electric and electronic parts. However, the polyalkylene terephthalate resin itself does not have sufficient vibration damping properties, and is only expected to have some effect due to the improvement in rigidity due to inorganic fillers such as reinforcing fibers. Is still not enough.

As described above, thermoplastic polyester resins such as polyalkylene terephthalate are excellent in various properties and also excellent in moldability. Therefore, development of a vibration damping material having excellent vibration damping properties using the same as a base resin is strongly expected. I have.

[Means for solving the problem]

In view of the present situation, the present inventors have made intensive studies on damping of polyester resin, and as a result, thermoplastic resin is mainly used, and a specific copolymer and further specific glass fiber are blended with this. As a result, they have found that a material having excellent vibration damping properties can be obtained, and have reached the present invention.

That is, the present invention provides (A) an olefin-based copolymer (a) comprising 60 to 97% by weight of a thermoplastic polyester resin and (B) a glycidyl ester of an α-olefin and an α, β-unsaturated acid. (C) With respect to 100 parts by weight of a resin component composed of 40 to 3% by weight of a graft or block copolymer containing (C) a major axis (longest linear distance of the section) perpendicular to the length direction and a minor axis (major axis and right angle) A vibration damping polyester resin composition comprising 5 to 200 parts by weight of glass fibers having a flat cross-sectional shape having a ratio of the longest linear distance in the direction of 1.5 to 5 and a molding thereof. It is intended to provide a molded product for a vibration damping member.

Hereinafter, the components of the vibration-damping polyester resin of the present invention will be described in detail.

First, the thermoplastic polyester resin (A) used in the present invention is a polyester obtained by polycondensation of a dicarboxylic acid compound and a dihydroxy compound, polycondensation of an oxycarboxylic acid compound, or polycondensation of a mixture of these three components. The effects of the present invention are obtained for both polyester and copolyester.

Illustrative examples of the dicarboxylic acid compound constituting the thermoplastic polyester resin used here include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid,
Known dicarboxylic acids such as adipic acid and sebacic acid and alkyl, alkoxy or halogen substituted products thereof. These dicarboxylic acid compounds can also be used for polymerization in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester. Two or more of these may be used.

Next, as examples of the dihydroxy compound constituting the polyester of the present invention, ethylene glycol, propylene glycol, butanediol, neopentyl glycol,
Hydroquinone, resorcin, dihydroxyphenyl,
Dihydroxy compounds such as naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, and diethoxylated bisphenol A; polyoxyalkylene glycols; and alkyl, alkoxy or halogen substituted products thereof. Alternatively, two or more kinds can be mixed and used.

Examples of the oxycarboxylic acid include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and substituted alkyl, alkoxy and halogen thereof. Further, derivatives of these compounds capable of forming an ester can also be used. In the present invention, one or more of these compounds are used.

In addition, a polyester having a branched or crosslinked structure using a small amount of a trifunctional monomer, that is, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, or the like may be used.

In the present invention, any of the thermoplastic polyesters produced by polycondensation using the above-mentioned compound as a monomer component can be used as the component (A) of the present invention, and can be used alone or as a mixture of two or more. However, preferably, polyalkylene terephthalate, more preferably polybutylene terephthalate and a copolymer mainly composed of polybutylene terephthalate are used.

Next, the copolymer used as the component (B) in the present invention refers to an olefin-based copolymer (a) comprising an α-olefin and a glycidyl ester of an α, β-unsaturated acid, or a graft containing such a polymer. Or it is a block copolymer.

Here, the α-olefin which is one of the monomers constituting the olefin copolymer (a) is ethylene,
Propylene, butene-1 and the like can be mentioned, but ethylene is preferably used. The glycidyl ester of α, β-unsaturated acid, which is another monomer constituting the component (a), is represented by the general formula (2) Wherein R ₁ represents a hydrogen atom or a lower alkyl group. Examples thereof include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate and the like, and particularly glycidyl methacrylate. Is preferably used. α
-The copolymer (a) can be obtained by copolymerizing an olefin (for example, ethylene) and an α, β-unsaturated glycidyl ester by a generally well-known radical polymerization reaction.

The olefin copolymer (a) is preferably composed of 70 to 99% by weight of α-olefin and 30 to 1% by weight of glycidyl unsaturated acid ester.

As the component (B), a graft or block copolymer having the copolymer (a) as a part in addition to the copolymer (a) is also suitable.

As the graft copolymer, the above-mentioned (a) and one or two or more kinds of a polymer or a copolymer (b) mainly composed of a repeating unit represented by the following general formula (1) are branched or crosslinked. Examples are structurally chemically bonded graft copolymers.

(Where R is hydrogen or a lower alkyl group, X is -COOH,
_{-COOCH 3, -COOC 2 H 5,} -COOC 4 H 9, -COOCH 2 CH (C 2 H 5) C 4 H
₉ , -Represents one or more groups selected from -CN. (B) As the segment, for example, polymethyl methacrylate, polyethyl acrylate, polybutyl acrylate, poly (2-ethylhexyl) acrylate, polystyrene, polyacrylonitrile, acrylonitrile-styrene copolymer, butyl acrylate and methyl methacrylate And a copolymer of butyl acrylate and styrene. These polymers or copolymers (b) are also prepared by radical polymerization of the corresponding vinyl monomers.

As the component (B) which is a feature of the present invention, the olefin copolymer (a) may be used alone,
Further, a graft copolymer having a branched or crosslinked structure in which a rigid body of (a) and a (co) polymer of (b) are chemically bonded at at least one point may be used. As described below, by containing such a polymer, an effect excellent in vibration damping property can be obtained.

The method for preparing the graft copolymer comprising the (a) segment and the (b) segment is not particularly limited, but can also be easily prepared by a radical reaction. For example, a graft radical (B) is prepared by generating free radicals in the polymer (b) with a peroxide or the like and melt-kneading the radicals with (a). Here, (a) for constituting the graft copolymer of the component (B) is used.
The ratio between (b) and (b) is suitably from 95: 5 to 40:60.

In the present invention, (A) a thermoplastic polyester resin and (B) an olefin-based copolymer of the resin component are each added in an amount of 60 to 97% by weight (A) and 40 to 3% by weight based on the total weight of the resin component. (B), preferably 70-90% by weight (A)
And 30 to 10% by weight (B).
If the amount of the component (B) is less than 3% by weight, the effect of improving the vibration damping property is not sufficiently exhibited, and if it exceeds 40% by weight, mechanical properties such as strength of the obtained resin are undesirably impaired.

In the present invention, a glass fiber (C) having a flatter cross-sectional shape is blended with the resin component.

The glass fiber (C) used in the present invention is characterized in that the cross section is not a circular shape as in the related art but a flat shape.

The composition containing the conventional circular glass has little effect on the improvement of the vibration damping property, which is the object of the present invention, whereas the glass fiber having a flat cross section as in the present invention is unexpectedly used. In this case, it was found that the damping property of the polyester resin was remarkably improved in combination with the effect of the component (B), and the rigidity, mechanical strength, and deformation resistance were also effective.

The glass fiber (C) having a flat cross-sectional shape used for this purpose is defined as a major axis (the longest linear distance of the section) and a minor axis (the longest in the direction perpendicular to the major axis) in a section perpendicular to the longitudinal direction. (Linear distance) is 1.5 to 5. As a specific shape, a cocoon, an oval, an ellipse, a semicircle or an arc, a rectangle or a similar shape thereof, and particularly those belonging to the cocoon, an oval and an ellipse are preferable.

Those having a ratio of the major axis to the minor axis smaller than 1.5 have little effect. However, if the ratio of the major axis to the minor axis exceeds 5, the production itself is difficult.

Next, as the cross-sectional area of the glass fiber (C) increases, a sufficient vibration-damping effect cannot be obtained as the glass fiber (C) increases. If the cross-sectional area is too small, it becomes difficult to manufacture the glass fiber (C) itself, and a handling problem occurs. Therefore, the cross-sectional area of the glass fiber in the present invention is 2 × 10 ⁻⁵ to 8 × 10 ⁻³ mm ² , preferably 8 × 10 ^−5.
８8 × 10 ⁻³ mm ² .

The length of the glass fiber (C) is arbitrary, but from the viewpoint of the mechanical strength of the molded article, the average fiber length in the molded article is at least
It is preferable that the length is longer than 30 μm, and it is appropriately selected according to the required performance. Usually, 50 to 1000 μm is preferable.

It is desirable to use a sizing agent or a surface treatment agent if necessary for use of these glass fibers (C) from the viewpoint of handling and adhesion to the resin. For example,
Known surface treatment agents and sizing agents such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds can be used. Glass fiber is subjected to surface treatment or convergence treatment with these compounds,
Alternatively, they may be added at the same time when the resin material is prepared.

Glass fiber (C) of the present invention having such a flat cross section
Is prepared, for example, by spinning using a nozzle having an appropriate hole shape such as an ellipse, an ellipse, a rectangle, or a slit as a bushing used to discharge molten glass. It is also prepared by spinning molten glass from a plurality of nozzles provided in close proximity having various cross-sectional shapes (including circular cross-sections) and joining the spun molten glass together to form a single filament. it can.

The amount of the glass fiber (C) used in the present invention is 5 to 200 parts by weight, preferably 10 to 150 parts by weight, more preferably 10 to 100 parts by weight per 100 parts by weight of the resin component. If the amount is less than 5 parts by weight, the desired effect cannot be obtained, and if it exceeds 200 parts by weight, molding becomes difficult. The amount of the above-mentioned functional surface treatment used in combination with the glass fiber (C)
0 to 10% by weight, preferably 0.05 to 5% by weight.

The molded article obtained from the thermoplastic polyester resin composition comprising the components (A), (B), and (C) has high rigidity, which has been the main means of conventional vibration damping, and further has vibration damping (vibration absorption). ), And has extremely good vibration damping properties that cannot be obtained with conventional glass fiber reinforced polyester resins.

Although the resin composition of the present invention exhibits excellent performance even when used as it is, the thermoplastic resin other than the component (B) of the present invention and the thermoplastic resin other than the component (C) of the present invention as far as the purpose is not hindered. It is possible to use a small amount of a fibrous, powdery and / or plate-like inorganic filler in an auxiliary manner.

Further, the composition of the present invention, in order to further impart desired properties according to its purpose, generally known substances added to the thermoplastic resin and thermosetting resin, such as antioxidants and heat stabilizers, Stabilizers such as ultraviolet absorbers, antistatic agents, lubricants,
A release agent, a coloring agent such as a dye or a pigment, a lubricant, a plasticizer, a crystallization accelerator, a crystal nucleating agent, and the like can be blended.

Next, the resin composition of the present invention is easily prepared by a method generally used as a conventional method for preparing a resin containing a reinforcing filler. That is, as the glass fiber, any of chopped strands or rovings or filaments which are bundled and cut to an appropriate size can be used as usual. Also, for example, after mixing each component, the mixture is kneaded and extruded with an extruder to prepare pellets, and then molded, a pellet (master batch) having a different composition is prepared, and the pellets are mixed in a predetermined amount (dilution). ) And subjecting it to molding, a method of obtaining a molded article of the desired composition after molding, a method of directly charging each component in a molding machine, and the like can be used.

As the molding method, any method generally known as a molding method of a thermoplastic resin is possible according to the shape, structure, and the like of a target part, but injection molding is most preferable.

〔Example〕

Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto. The evaluation method is as follows.

Measurement of vibration damping rate: Form a test piece about 13 mm wide, about 130 mm long and about 3 mm thick, fix the test piece as shown in Fig. 1 and give a certain free vibration to one end, and use a digital oscilloscope Then, the change in time and output voltage (decay curve) was measured, and the logarithmic decay rate per unit time (second) was determined using the following equation.

T: cycle (sec) X _n ; amplitude at a certain time X _{n + 1} ; amplitude one cycle after X _n Flexural modulus: Flexural modulus was measured according to ASTM D790.

Examples 1 to 9 As component (A), polybutylene terephthalate was used.
(B) an olefin-based copolymer or graft copolymer described later as a component; and (C) a converged 3 mm long chopped strand glass fiber having a cocoon-shaped cross-sectional shape having a ratio of major axis to minor axis of about 2.3. Were added and mixed and melt-kneaded with an extruder to obtain pellets.

Next, a test piece was prepared from the pellet by injection molding and evaluated. Table 1 shows the results.

Comparative Examples 1 to 10 Polybutylene terephthalate (A) to which no component (B) was added, and that only a chopped glass fiber of 3 mm in length having a circular cross section not belonging to the requirements of the present invention was added, and further glass fiber And the component (B) were added and mixed as shown in Table 2, and pellets were prepared in the same manner as in the examples, and the above evaluation was performed. Table 2 shows the results.

Example 10 and Comparative Example 11 Pellets were prepared in the same manner as in Example 3 except that a mixed polymer of polybutylene terephthalate and modified polyethylene terephthalate was used instead of the polybutylene terephthalate used in Example 3 as the component (A). The above evaluation was performed. In addition, for comparison, evaluation was performed on a glass fiber having a circular cross section. The results are shown in Tables 1 and 2, respectively.

Example 11 Example 3 was repeated except that the glass fiber used in Example 3 was replaced by a 3 mm chopped strand glass fiber having an elliptical cross-sectional shape with a ratio of major axis / minor axis of about 1.8 instead of the glass fiber used in Example 3. Similarly, pellets were prepared and evaluated as described above. Table 1 shows the results.

(Note) * 1; Isophthalic acid-modified polyethylene terephthalate obtained by polymerizing terephthalic acid, isophthalic acid and ethylene glycol * 2; (B) The olefin-based copolymer and the graft copolymer used in the examples are as follows: The abbreviations are shown in Tables 1-2.

(Abbreviation) (Specific substances and their composition) E / GMA: Ethylene-glycidyl methacrylate (8
5:15) Copolymer E / GMA-g-AN / S: Graft copolymer of E / GMA (70) and acrylonitrile-styrene copolymer (30) E / GMA-g-PS: E / GMA Graft copolymer of (70) and polystyrene (30) E / GMA-g-PMMA: Graft copolymer of E / GMA (70) and polymethyl methacrylate (30) E / GMA-g-MMA / BA: E / GMA (70) and graft copolymer of methyl methacrylate-butyl acrylate copolymer (30) * 3; long diameter / short diameter ratio Examples 1 to 10 and Comparative Example 1 were about 2.3, and Example 11 is about 1.8 [Effect of the Invention] As is clear from the above description and Examples, a specific olefin-based copolymer and a polyester resin composition of the present invention comprising a glass fiber having a specific cross-sectional shape are blended. Can greatly improve the vibration damping of molded products,
Moreover, compared to conventional glass fiber reinforced polyester resin,
There is no inferiority in mechanical properties of strength and rigidity, and it has an excellent vibration damping effect.

Therefore, the composition of the present invention is extremely useful as an audio equipment part or an automobile part having an oscillation source such as an engine or a motor, for example, a structural part such as a room mirror or a fender mirror, or a direct structural part such as an OA equipment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a measurement situation of a vibration damping rate in the embodiment.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-229065 (JP, A) JP-A-62-283853 (JP, A) JP-A-62-202837 (JP, A) JP-A-62-202837 187136 (JP, A) JP-A-61-219731 (JP, A)

Claims (6)

(57) [Claims] 1. An olefin copolymer (a) or (a) comprising (A) 60 to 97% by weight of a thermoplastic polyester resin and (B) a glycidyl ester of an α-olefin and an α, β-unsaturated acid. (C) With respect to 100 parts by weight of the resin component comprising 40 to 3% by weight of the graft or block copolymer, (C) the major axis (longest linear distance of the section) and the minor axis (longest direction perpendicular to the major axis) (A longest linear distance) is 1.5 to 5; and 5 to 200 parts by weight of a glass fiber having a flat cross-sectional shape is blended. 2. The vibration-damping polyester resin composition according to claim 1, wherein (A) the thermoplastic polyester resin is a polyester mainly comprising polybutylene terephthalate. 3. The vibration damping property according to claim 1, wherein the olefin copolymer (a) constituting the component (B) is a copolymer comprising ethylene and a glycidyl ester of α, β-unsaturated acid. Polyester resin composition. (4) The component (B) comprises (a) and one or more kinds of a polymer or copolymer (b) mainly composed of a repeating unit represented by the following general formula (1): The vibration-damping polyester resin composition according to claim 1, which is a graft copolymer chemically bonded in a branched or cross-linked structure. (Where R is hydrogen or a lower alkyl group, X is -COOH, -C
_{OOCH 3, COOC 2 H 5,} -COOC 4 H 9, -COOCH 2 CH (C 4 H 5) C 4 H 9, -Represents one or more groups selected from -CN. ) 5. The glass fiber of component (C) is mainly composed of a cross-sectional shape selected from a cocoon, an oval, an ellipse, a semicircle or an arc, a rectangle or a similar shape. Item 5. The vibration damping polyester resin composition according to any one of Items 1 to 4. 6. A vibration-damping part obtained by molding the vibration-damping polyester resin composition according to any one of claims 1 to 5.